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https://www.answers.com/Q/Jake_and_Brenda_drove_at_a_speed_of_30_mph_for_1_hour_Then_they_turned_around_and_drove_45_mph_until_they_were_back_where_they_started_What_is_true_about_their_average_speed_and_average_velocity | 0
# Jake and Brenda drove at a speed of 30 mph for 1 hour Then they turned around and drove 45 mph until they were back where they started What is true about their average speed and average velocity?
Wiki User
2009-10-20 16:28:49
Best Answer
their average speed is greater than their average velocity.
Evan Carter
Lvl 4
2021-08-19 15:16:35
This answer is:
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Cecile Heidenreich
Lvl 1
2021-08-21 08:05:59
awesome, thanks
Danika Abbott
Lvl 1
2021-08-22 01:06:08
I think this is the right answer.
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Wiki User
2009-10-20 16:28:49
Their average speed is greater than their average velocity
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Q: Jake and Brenda drove at a speed of 30 mph for 1 hour Then they turned around and drove 45 mph until they were back where they started What is true about their average speed and average velocity?
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View results | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.827568531036377, "perplexity": 7895.267367014627}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320305420.54/warc/CC-MAIN-20220128043801-20220128073801-00532.warc.gz"} |
https://www.gradesaver.com/textbooks/math/algebra/intermediate-algebra-6th-edition/chapter-4-section-4-1-solving-systems-of-linear-equations-in-two-variables-exercise-set-page-213/88 | ## Intermediate Algebra (6th Edition)
$x\lt1875$
When the revenue graph is lower than the cost graph, the company loses money. In the given graph, this occurs when $x\lt1875 .$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.31974637508392334, "perplexity": 1598.4691064925037}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376823442.17/warc/CC-MAIN-20181210191406-20181210212906-00200.warc.gz"} |
https://math.stackexchange.com/questions/3624664/distance-of-point-from-a-particular-line | # Distance of point from a particular line
The number of points on the line $$3x + 4y = 5$$, which are at a distance of $$sec^2\theta+2cosec^2\theta$$ ,$$\theta \in \mathbb{R}$$ from the point $$(1, 3)$$, is
(1) 1
(2) 2
(3) 3
(4) infinite
My approach is as follow the least distance of $$3x+4y=5$$ from the point $$(1,3)$$ is $$2$$ which is perpendicular distance. The point from $$3x+4y=5$$ from the point $$(1,3)$$ may not be perpendicular. The distance $$sec^2\theta+2cosec^2\theta$$ is always greater than $$2$$ so we need to find the number of points valid for $$sec^2\theta+2cosec^2\theta$$ which I am not able to find.
• Is the answer supposed to depend on $\theta$? – Parcly Taxel Apr 14 at 7:16
The function $$\sec^2\theta+2\csc^2\theta$$ is unbounded in the positives, so there are infinitely many points that can satisfy the condition.
By C-S $$\frac{1}{\cos^2\theta}+\frac{2}{\sin^2\theta}=(\cos^2\theta+\sin^2\theta)\left(\frac{1}{\cos^2\theta}+\frac{2}{\sin^2\theta}\right)\geq(1+\sqrt2)^2,$$ which gives a range of $$\frac{1}{\cos^2\theta}+\frac{2}{\sin^2\theta}$$: $$\left[(1+\sqrt2)^2,+\infty\right)$$ and there are infinitely many such points.
• if the minimum is $(1+\sqrt{2})^2$, the range starts with it, does not it? – farruhota Apr 14 at 9:49
• should not the range be: $[(1+\sqrt{2})^2,+\infty)$? – farruhota Apr 14 at 10:26 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 16, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9089899063110352, "perplexity": 170.05794387264234}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400188841.7/warc/CC-MAIN-20200918190514-20200918220514-00001.warc.gz"} |
http://mathoverflow.net/questions/59633/maximum-flow-with-negative-capacities/59785 | # Maximum flow with negative capacities?
I'm trying to compute an (s-t) maximum flow through a network which includes a number of arc pairs ((u,v), (v,u)) that have equal, negative capacities (weights). I'm not aware of any efficient algorithms that solve this problem directly, so I am trying to think of a way to transform the problem so that it can be passed to standard max-flow algorithms that assume all arc capacities are non-negative.
The only hint I could find online was a question in a 1999 homework assignment which asks students to "Show how to reduce the problem of maximum flow with possibly negative capacities to two maximum flow problems both with nonnegative capacities." (The original can be seen here: http://www.cs.cmu.edu/afs/cs/academic/class/15750-s99/www/homeworks/hw4.ps )
How can this be done?
Edit #1: I should explain the origin of these ((u,v),(v,u)) pairs. What I am really trying to do is solve an s-t maximum flow in a graph that is essentially undirected. By "essentially undirected" I mean a graph that is undirected except for arcs with source s and target in the undirected graph, and arcs with source in the undirected graph and target t. Of course, this kind of "partially directed" graph must be translated into a normal directed graph for any s-t max flow algorithm. To do this, I am applying the standard transformation of replacing every undirected edge (u<->v) (with weight c) with a pair of directed arcs (u->v) and (v->u) with weight c. Since the original graph sometimes has negative edge weights, these ((u,v),(v,u)) pairs with equal negative weights arise.
-
Can you clarify the problem? I assume that an arc with capacity -7 needs to have a flow of -7 or less, right? But can an arc with positive capacity get a negative flow? – Stefan Geschke Mar 26 '11 at 8:17
Ok, I have just read the problem in the link. Still not so clear. If you have an arc pair $\{(u,v),(v,u)\}$, both with the same negative capacity, what would be an admissible flow on these arcs? Or is one capacity positive and the other negative, of the same absolute value, so that you essentially specify your flow at this arc? – Stefan Geschke Mar 26 '11 at 8:21
If arcs ${(u,v),(v,u)}$ both have capacities of -7, isn't this the same as saying that both arcs must have positive flows of at least 7 units? – Brian Borchers Mar 26 '11 at 14:20
The correspondence between max flow with lower capacities and max flow with negative capacities as described in the linked homework problem is based on the convention that $f(u,v)=-f(v,u)$ for all arc pairs $\{(u,v),(v,u)\}$. http://computingscience.nl/docs/vakken/an/an-maxflow.ppt contains a reduction of max flow with lower capacities to the solution of two standard max flow problems, thus solving the homework question. If I understand your problem correctly, it is a bit more complicated: A weight of $-7$ on an (undirected) edge $\{u,v\}$ means that you want to send at least 7 units of flow either from $u$ to $v$ or from $v$ to $u$. As far as I can see, for this problem the standard transformation of replacing the edge by an arc pair does not work. In the standard case only one of the arcs $(u,v)$ and $(v,u)$ is used in an optimal solution, and its flow value can be used as the value for the undirected edge. But how would you transfer $f(u,v)=-9$, $f(v,u)=-12$ back to the undirected model?
Practically, the first thing I would try is to write the original problem as a mixed integer program (I guess you have to model the choices for the arc directions with binary variables) and throw it into a general purpose solver (Cplex, Gurobi, http://zibopt.zib.de, http://www.coin-or.org/ ).
-
Thanks everyone for your comments. Unfortunately, I now realize that I was trying to do the impossible. As Brian's comment suggests, I can't have a net flow of +7 in both directions between a pair of nodes. As Kali points out, a choice must be made at every such arc-pair that leads to a combinatorial explosion.
I came to the realization yesterday: by the duality of max-flow and min-cut, if I could solve a max-flow problem with negative edge weights then I could solve a min-cut problem with negative edge weights. However, since I can translate any (NP-complete) max-cut problem into a min-cut problem by negating all the edge weights, I can't expect to solve such problems in P-time.
I see now (thanks to Kali) that the homework question makes the (standard) assumption of what I think is called "skew symmetry". The problem I have is incompatible with this and therefore isn't merely a network flow problem with negative edge weights.
-
If you are just interested in the solution to your problem (and not in obtaining it by a provably polynomial algorithm) I still recommend to simply try solving the MIP. – Thomas Kalinowski Mar 28 '11 at 1:33
Yes, I will probably do this. Since the negative capacity edge pairs are static and reasonably limited in number, an MIP solver is probably going to do a reasonable job. I can also make use of suboptimal solutions, so I agree it is a good way forward. – Fumiyo Eda Mar 28 '11 at 6:26
@Fumiyo, What did you end up doing? I have been working on this problem to come to the same conclusion you did regarding the incompatibility of negative undirected weights with the standard "skew symmetry" assumption. I suspected from the beginning this problem would be NP-hard. Did you find a good approximation? – SchighSchagh May 3 '14 at 6:21
The problem you describe sounds like an energy minimization on a Markov Random Field (MRF).
Min E = sum[D(p)] + sum[V(p,q)]
where p, q is a binary labelling = {sink=0, source=1}.
The first term of E sums over all the nodes in the undirected graph. D(p=0) is the weight on the source-to-node edge and D(p=1) the weight on the node-to-sink edge.
The second term of E sums over all edges in the undirected graph, where p is the label on one end of the edge and q the label on the other end.
The standard min-cut with positive weights correponds to: V(0,0)=V(1,1)=0 and V(0,1)=V(1,0)=weight. More general, if V(p,q) satisfies the submodular condition on all edges, then minimizing E is the same as an s-t max-flow\min-cut.
Submodular: V(0,1) + V(1,0) >= V(0,0) + V(1,1)
If there are (some) negative weighted edges, these do not satisfy submodularity. Instead they are supermodular.
Supermodular: V(0,1) + V(1,0) <= V(0,0) + V(1,1)
If all edges are supermodular, I guess there is an equivalence with max-cut.
However, the problem you describe coontains a mixture of submodular (positive weighted) and supermodular (negative weighted) edges. This is indeed NP-hard. But how to solve it? You might consider looking into Quadratic Pseudo Boolean Optimization (QPBO): Wikipedia
- | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8422703742980957, "perplexity": 373.9414170146415}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246661733.69/warc/CC-MAIN-20150417045741-00303-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://de.maplesoft.com/support/help/view.aspx?path=Database/Result/GetType&L=G | GetType - Maple Help
Result
GetType
get the SQL type of a column
Calling Sequence result:-GetType( index )
Parameters
result - Result module index - integer or string; the column for which the type is returned
Description
• GetType returns the SQL type of the column indicated by index.
• If index is an integer, it is used to index into the current Result module's table. If index is a string, it is the name of the column.
• The type returned by GetType can be used in an explicit cast to make Maple perform a particular type conversion. For more information, see conversions.
Examples
Create a Result.
> $\mathrm{driver}≔\mathrm{Database}\left[\mathrm{LoadDriver}\right]\left(\right):$
> $\mathrm{conn}≔\mathrm{driver}:-\mathrm{OpenConnection}\left(\mathrm{url},\mathrm{name},\mathrm{pass}\right):$$\mathrm{res}≔\mathrm{conn}:-\mathrm{ExecuteQuery}\left("SELECT name FROM animals"\right):$$\mathrm{res}:-\mathrm{GetType}\left(1\right)$
${\mathrm{INTEGER}}$ (1)
> $\mathrm{res}:-\mathrm{GetType}\left(2\right)$
${\mathrm{VARCHAR}}$ (2)
> $\mathrm{res}:-\mathrm{GetType}\left(3\right)$
${\mathrm{INTEGER}}$ (3)
> $\mathrm{res}:-\mathrm{GetType}\left(4\right)$
${\mathrm{DOUBLE}}$ (4)
> $\mathrm{res}:-\mathrm{GetType}\left("id"\right)$
${\mathrm{INTEGER}}$ (5)
> $\mathrm{res}:-\mathrm{GetType}\left("name"\right)$
${\mathrm{VARCHAR}}$ (6)
> $\mathrm{res}:-\mathrm{GetType}\left("number"\right)$
${\mathrm{INTEGER}}$ (7)
> $\mathrm{res}:-\mathrm{GetType}\left("mass"\right)$
${\mathrm{DOUBLE}}$ (8) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 19, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8232582211494446, "perplexity": 2721.3020079771663}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500154.33/warc/CC-MAIN-20230204205328-20230204235328-00698.warc.gz"} |
http://www.dotnetspark.com/links/4957-http-400-bad-request-error-when-uploading.aspx | Welcome :Guest
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Hi I have a task which uses a custom form which is part of a custom workflow. The form incorporates an asp fileUpload control to allow a user to browse for a local file which they can then select and it will be upload a file to a folder in a document library. The first time this action is performed the folder in the document library will not exist so the code creates a folder and then uploads the file to it. The problem I have is, the first time users try and upload a file the directory is created in the document library as expected, but then the user gets redirected to the standard SharePoint Access Denied page. If the user goes back to the task list, then loads the task web page again, selects the same file and hits upload, then the file is uploaded fine. All subsequent file uploads work fine after that for all users. Users have Contribute permissions on the document library. The code to do the upload is as follows. The task has a "CR Number" associated with it, which the directory in the doc library should be called. It uploads the file to a stream. Then gets the url of the web and works out the file url and uploads it. The creation and checking of the folder in the doc library happens in the getDirUrl method. /// <summary> /// Processes an uploaded file. /// </summary> /// <param name="
RE: ASP:Upload control . Uploading into a SharePoint Document Library Subfolder and FILE NOT FOUND error Two Issues, apparently unrelated. I have subfolders like this /ApplicantDocuments/20 and /ApplicantDocuments/21 (where 20 and 21 are my subfolders and ApplicantDocuments is my library. 1. The below function is erroring with file not found, but I confirmed I'm sending the fully qualify path (i.e c:\test.txt) to System.IO.FileStream content = System.IO.File.Open(documentFileName, System.IO.FileMode.Open); 2. Even if it worked, looking at the code, I'm not using argument foldername. I'm passing 20 to the argument. How can I make sure it uploads into subfolder 20 of ApplicantDocuments? Thank you. Just testing in test environment. Will tighten code once it works. public void UploadDocumentToSite(string foldername, string documentFileName) { SPSite siteCollection = new SPSite("https://xxxxxx"); SPWeb web = siteCollection.OpenWeb(); //SPSite.AllowUnsafeUpdates = true; //Web.AllowUnsafeUpdates = true; string Lib = "ApplicantDocuments"; SPFolder destFolder = web.GetFolder(Lib); sendmail(documentFileName+" "+foldername);
Hi,
We have a set of documents in a document library, which we are trying to download. if i click on the document and try to download, it takes a lot of time and then reports a error message.
Exception from HRESULT: 0x80041050
Now when we also try to upload documents, it does not allow us to upload the documents and reports a exception.
We tried to research through through the error, it gaves us while downloading the document, it is somewhat related to the Antivirus issues and looks like a document that is infected. This is only related to some documents and not all documents.
http://support.microsoft.com/?id=928169
Let us know if there is any where to work around this issue and allow users to upload and download documents or how to tackle the antivirus issue.
It looks like the SharePoint antivirus has flagged off some of the so-called infected documents with some non-zero values, the resolution to this as suggested by microsoft is to re-run the anti-virus, so that the document value can be set to zero again and have the file downloaded.
Your help will be highly appreciated in this regards.
Regards
Ram
&n
### Uploading Large files via Web Service | HTTP Error 413 - Request Entity Too Large.
Hello all -
I am trying to implement a Web Service, which accepts a binary file as a byte array for one of its parameters. It's workings are based on this article:
Anyhow, the size of the file can be significant as the types of files being uploaded through the service are MP4 Video files. The service works on my WinXP SP2 localhost, but when I implement it onto a 2003 Server and try to consume the service, I get the following error back from the web service:
The request failed with HTTP status 413: Request Entity Too Large.
I do a little searching around and find a few articles indicating that I need to adjust my "MaxReadAheadLength" property in IIS. A good example of one of those articles is here:
The suggestion from the article is to execute the following command on the web server:
FYI, the adsutil.vbs is in your IIS's AdminScripts directory. I'm guessing that the /1/ part of the command is th
### Error adding a document library to a site
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Hi all, I want to upload the doc file into SharePoint document library using the FileUpload control. For that I am created a new document library in my SharePoint site. But I am not getting the path of Document library where I want to upload the file. Waiting for your valuable response. Regards,-Kaustubh
### ASP.NET 4.0 FormsAuthentication Transition (HTTP Error 400 - Bad Request.)
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### Programmatically Uploading a Documents into a Document Library using web part ?
Hii, Can anyone can help me how to upload the documents to the document library in sharepoint foundation using customization for what our deafult upload.aspx will do !!!!! Thanks in advance !!!! Rgrds//Praveen
### WCF HTTP POST - The remote server returned an error: (400) Bad Request. - URGENT
client & sever code below-------------------------------------------- [ServiceContract(Namespace = "http://test.mydomain.com")] public interface IMyService{[WebInvoke(UriTemplate = "", BodyStyle = WebMessageBodyStyle.Bare, Method = "POST")] Stream SaveXML(Stream input); } ----------------------[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior(Namespace = "http://test.mydomain.com")] public class MyService : IMyService{ ÃÂ public Stream SaveXML(Stream input)ÃÂ ÃÂ { ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ StreamReader streamReader = new StreamReader(input);ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ string rawString = streamReader.ReadToEnd();ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ streamReader.Dispose(); ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ // here need to save the input stream to xml format fileÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ //ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ Encoding encoding = Encoding.GetEncoding("ISO-8859-1");ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml";ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ byte[] returnBytes = encoding.GetBytes(rawString);ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ return new MemoryStream(returnBytes);ÃÂ ÃÂ } } --------------------------------------------------Client Code ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ string postData = GetXmlString("d:\\text.xml"); // user functionÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ WebRequest request = WebRequest.Create("http://test.mydomain.com/myservice.svc");ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ request.Method = "POST";ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ byte[] byteArray = Encoding.UTF8.GetBytes(p
Hi i am writing a event receiver to get the file creation date after the document is uploaded to the document library.
When a document library is uploaded to a document library the created date is overwriten by the uploaded date.
issues 1) i am not getting the folder path to get the filecreation date for system.io.file.getcreation() method
public override void ItemAdded(SPItemEventProperties properties)
{
try
{
properties.ListItem["Created"] =CreationTime(date);
properties.ListItem["Title"] = itemurl;
properties.ListItem.Update();
}
catch (Exception ex)
{
}
}
public CreationTime(SPItemEventProperties properties) {
try
{
using (SPSite site = new SPSite("http://test"))
{
SPWeb oWebsiteSrc = site.OpenWeb();
SPFileCollection fileCollection = oWebsiteSrc.Files ;
//get the filelocation of the current document library
string filepath = fileCollection.Web.Lists["test"].Folders.ToString();
SPList oList = site.AllWebs["jtest"].Lists["test"];
SPFolder folder=oWebsiteSrc.Files.Folder;
SPListItem fileitems =oWebsiteSrc.Lists["test"].Items[0] ;
### Currency and number column error with office 2007 document formats in SharePoint 2010 library
Hi there,
The following error occurred within a SharePoint 2010 document library:
As I tried to test out the new SharePoint 2010 environment I changed the metadata from a few documents within a document library. I noticed that the data from the currency und number field was incorrect from a few documents. The numbers looked like that the decimal separator were ignored. For an example: 123.456,78 was saved as 12.345.678.
At first I thought it could be a language incompabilty but if that would be the case: Why would there be other documents which show the correct number?
I created another document library to recreate this error. And there I noticed the real reason: Every time I changed these fields from a document which was saved in the office 2007 format the error occurred. The metadata from the documents in the office 2003 format were correct.
Has anyone a similar problem or got an idea how to solve this problem?
System Specs:
Frontend: Windows Server 2008 SP2 ent
### Getting error msg while trying to upload a document inot the document library using the form which i
I have designed an upload form with the columns that have to be filled in while uploading a document into the document library.The form is designed in .net.
I get "Error Access Denied" message when i try to upload the document using that upload form.When i go back to site,the document is uploaded in that particular document library.But this problem doesnot exist when i upload the document as admin.There is no " Error Access Denied" message.I have checked the document library permissions.The problem is not with the permission to that particular document library.
Can someone help me out in this issue?
### Restore a previous version of a document in a document library - error
When I try to restore a previous version of a document in a document library, I get this error message:
"Updates are currently disallowed on GET requests. To allow updates on a GET, set the AllowUnsafeUpdates' property on SPWeb"
I am NOT running any custom code anywhere on my SharePoint site
### Delete document library throws "Exception from HRESULT: 0x80040E14" error
I am running WSS 3.0 SP2 running the Feb 2010 cumulative update. I have a particular document library I am attempting to delete. When I click on delete in the GUI, I get a page that says "Exception from HRESULT: 0x80040E14". Everything I've found so far on the web says this is caused by a SQL server that is out of space. That is not the problem in my case.
Additionally, I have looked at the logs in Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\LOGS and found the root cause. When I try to delete this document library, two errors are added to the log. They are
• 06/16/2010 09:45:55.72 w3wp.exe (0x1798) 0x0D44 Windows SharePoint Services Database 6f8g Unexpected Unexpected query execution failure, error code 8144. Additional error information from SQL Server is included below. "Procedure or function proc_SecGetI
Categories:
ASP.Net Windows Application .NET Framework C# VB.Net ADO.Net Sql Server SharePoint Silverlight Others All | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.34958910942077637, "perplexity": 3284.294767167972}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988725470.56/warc/CC-MAIN-20161020183845-00171-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://math.stackexchange.com/users/45776/fff?tab=summary | fff
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Mathematics 126 rep 111 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6424375176429749, "perplexity": 11332.52966005874}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461860111455.18/warc/CC-MAIN-20160428161511-00190-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://trilinos.sandia.gov/packages/docs/r10.4/packages/nox/doc/html/classNOX_1_1StatusTest_1_1NormF.html | # NOX::StatusTest::NormF Class Reference
Various convergence tests based on the norm of the residual. More...
#include <NOX_StatusTest_NormF.H>
Inheritance diagram for NOX::StatusTest::NormF:
[legend]
Collaboration diagram for NOX::StatusTest::NormF:
[legend]
List of all members.
## Public Types
enum ScaleType { Unscaled, Scaled }
Type that determines whether to scale the norm by the problem size.
More...
enum ToleranceType { Relative, Absolute }
Type that determines whether the norm is absolute or relative to the intial guess.
More...
## Public Member Functions
NormF (double tolerance, NOX::Abstract::Vector::NormType ntype, ScaleType stype=Scaled, const NOX::Utils *u=NULL)
Constructor for absolute norm.
NormF (double tolerance, ScaleType stype=Scaled, const NOX::Utils *u=NULL)
Constructor for absolute norm.
NormF (NOX::Abstract::Group &initialGuess, double tolerance, NOX::Abstract::Vector::NormType ntype, ScaleType stype=Scaled, const NOX::Utils *u=NULL)
Constructor with initial guess (for relative norms).
NormF (NOX::Abstract::Group &initialGuess, double tolerance, ScaleType stype=Scaled, const NOX::Utils *u=NULL)
Constructor with initial guess (for relative norms).
virtual ~NormF ()
Destructor.
virtual NOX::StatusTest::StatusType checkStatus (const NOX::Solver::Generic &problem, NOX::StatusTest::CheckType checkType)
Test the stopping criterion
virtual NOX::StatusTest::StatusType getStatus () const
Return the result of the most recent checkStatus call.
virtual ostream & print (ostream &stream, int indent=0) const
Output formatted description of stopping test to output stream.
virtual void reset (double tolerance)
Resets the user specified absolute or relative tolerance.
virtual void reset (NOX::Abstract::Group &initialGuess, double tolerance)
Resets the user specified relative tolerance.
virtual double getNormF () const
Returns the value of the F-norm computed in the last call to checkStatus.
virtual double getTrueTolerance () const
Returns the true tolerance.
virtual double getSpecifiedTolerance () const
Returns the specified tolerance set in the constructor.
virtual double getInitialTolerance () const
Returns the initial tolerance.
## Detailed Description
Various convergence tests based on the norm of the residual.
Use the constructor to define the test based on the type of scaling (see ScaleType) and the type of Tolerance (see Tolerance).
If checkStatus is called with the type set to NOX::StatusTest::None, then the status is set to NOX::StatusTest::Unevaluated and returned. (Also normF is set to 0.0.)
If checkStatus is called on a problem where the solution group does not have F evaluated (i.e., problem.getSolutionGroup().isF() is false), then the status is set to NOX::StatusTest::Unconverged and returned. (Also normF is set to -1.0.)
Finally, we return NOX::StatusTest::Converged if , and NOX::StatusTest::Unconverged otherwise. Here represents the norm of and represents the tolerance, as described below.
Let denote an optional scale factor defined as
• if sType in the constructor is NOX::NormF::Scaled, and
Then is defined as follows:
• If nType in the constructor is Abstract::Vector::TWO, then
• If nType in the constructor is Abstract::Vector::ONE, then
• If nType in the constructor is Abstract::Vector::INF, then
We set as follows, based on the value of tolerance in the constructor.
• If an initial guess is provided, we use a relative tolerance defined by
Here is the (as defined above) associated with the initial guess.
• Otherwise, we use an absolute tolerance defined by
## Member Enumeration Documentation
Type that determines whether to scale the norm by the problem size.
Enumerator:
Unscaled No norm scaling. Scaled Scale the norm by the length of the vector.
Type that determines whether the norm is absolute or relative to the intial guess.
Enumerator:
Relative Relative to starting guess. Absolute Absolute.
## Constructor & Destructor Documentation
NOX::StatusTest::NormF::NormF ( double tolerance, NOX::Abstract::Vector::NormType ntype, ScaleType stype = Scaled, const NOX::Utils * u = NULL )
Constructor for absolute norm.
This constructor defaults to the Absolute tolerance type.
References NOX::StatusTest::Unevaluated.
NOX::StatusTest::NormF::NormF ( double tolerance, ScaleType stype = Scaled, const NOX::Utils * u = NULL )
Constructor for absolute norm.
This constructor defaults to the Absolute ToleranceType and TWO NormType.
NOX::StatusTest::NormF::NormF ( NOX::Abstract::Group & initialGuess, double tolerance, NOX::Abstract::Vector::NormType ntype, ScaleType stype = Scaled, const NOX::Utils * u = NULL )
Constructor with initial guess (for relative norms).
This constructor defaults to the Relative tolerance type.
NOX::StatusTest::NormF::NormF ( NOX::Abstract::Group & initialGuess, double tolerance, ScaleType stype = Scaled, const NOX::Utils * u = NULL )
Constructor with initial guess (for relative norms).
This constructor defaults to the Relative ToleranceType and TWO NormType.
## Member Function Documentation
NOX::StatusTest::StatusType NOX::StatusTest::NormF::checkStatus ( const NOX::Solver::Generic & problem, NOX::StatusTest::CheckType checkType ) [virtual]
Test the stopping criterion
The test can (and should, if possible) be skipped if checkType is NOX::StatusType::None. If the test is skipped, then the status should be set to NOX::StatusTest::Unevaluated.
Implements NOX::StatusTest::Generic.
The documentation for this class was generated from the following files:
• NOX_StatusTest_NormF.H
• NOX_StatusTest_NormF.C
Generated on Wed Apr 13 09:59:46 2011 for NOX by 1.6.3 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7778778076171875, "perplexity": 16461.418184085294}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1406510273012.22/warc/CC-MAIN-20140728011753-00373-ip-10-146-231-18.ec2.internal.warc.gz"} |
https://tug.org/pipermail/texhax/2007-August/008869.html | # [texhax] How to suppress subfloat label
Brandon Kuczenski brandon at 301south.net
Thu Aug 9 20:07:13 CEST 2007
Hello all,
I am using the subfig package to insert subfigures in a document. I would
like one of my figures to contain both a long caption and a short caption,
so that the long caption appears beneath the figure but the short caption
appears in the List of Figures. My code looks like this:
\begin{figure}
\centering
\subfloat[ ... very long caption ... ]{\includegraphics...}
\caption{A short, manageable caption.}
\label{foo}
\end{figure}
This renders as follows:
-----------------
graphics
-----------------
(a) ... very long
caption .......
Figure 1: A short, manageable caption.
My question: is there any way to suppress the "(a)" subfigure label at the
beginning of the subfloat caption? I would like to do this just for one
subfigure, not globally.
Thanks in advance!
-Brandon
More information about the texhax mailing list | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9499085545539856, "perplexity": 7509.956053031529}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-35/segments/1566027313617.6/warc/CC-MAIN-20190818042813-20190818064813-00354.warc.gz"} |
http://math.stackexchange.com/questions/323833/what-are-piecewise-ck-functions?answertab=oldest | # What are piecewise-$C^k$ functions
What are piecewise-$C^k$ functions? How can I know if a function is piecewise-$C^k$ or not?
-
A piecewise-$C^{k}$ is a function whose domain can be broken into intervals, upon which the restriction to each individual interval is $C^k$ (but that might fail at endpoints). – Isaac Solomon Mar 7 '13 at 18:06
@IsaacSolomon What's a $C^k$ interval? – saadtaame Mar 7 '13 at 18:11
I think it's not $C^k$ interval but in that interval the function is $k$ times continuously differentiable. – user45099 Mar 7 '13 at 18:25
Any function with k continuous derivatives is called a $C^k$ function. And look here as to what piecewise means-http://en.wikipedia.org/wiki/Piecewise.
- | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7750453948974609, "perplexity": 1411.832426656483}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-42/segments/1413507446525.24/warc/CC-MAIN-20141017005726-00318-ip-10-16-133-185.ec2.internal.warc.gz"} |
http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002473?imageURI=info:doi/10.1371/journal.pcbi.1002473.g005 | Research Article
# Ligand-Dependent Conformations and Dynamics of the Serotonin 5-HT2A Receptor Determine Its Activation and Membrane-Driven Oligomerization Properties
• Affiliation: Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York, United States of America
X
• Affiliation: Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York, United States of America
X
• Affiliation: Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York, United States of America
X
• Affiliation: Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York, United States of America
X
• [email protected]
Affiliations: Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York, United States of America, The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, New York, United States of America
X
• Published: April 19, 2012
• DOI: 10.1371/journal.pcbi.1002473
## Abstract
From computational simulations of a serotonin 2A receptor (5-HT2AR) model complexed with pharmacologically and structurally diverse ligands we identify different conformational states and dynamics adopted by the receptor bound to the full agonist 5-HT, the partial agonist LSD, and the inverse agonist Ketanserin. The results from the unbiased all-atom molecular dynamics (MD) simulations show that the three ligands affect differently the known GPCR activation elements including the toggle switch at W6.48, the changes in the ionic lock between E6.30 and R3.50 of the DRY motif in TM3, and the dynamics of the NPxxY motif in TM7. The computational results uncover a sequence of steps connecting these experimentally-identified elements of GPCR activation. The differences among the properties of the receptor molecule interacting with the ligands correlate with their distinct pharmacological properties. Combining these results with quantitative analysis of membrane deformation obtained with our new method (Mondal et al, Biophysical Journal 2011), we show that distinct conformational rearrangements produced by the three ligands also elicit different responses in the surrounding membrane. The differential reorganization of the receptor environment is reflected in (i)-the involvement of cholesterol in the activation of the 5-HT2AR, and (ii)-different extents and patterns of membrane deformations. These findings are discussed in the context of their likely functional consequences and a predicted mechanism of ligand-specific GPCR oligomerization.
## Author Summary
The 5-HT2A receptor for the neurotransmitter serotonin (5-HT) belongs to family A (rhodopsin-like) G-protein coupled receptors (GPCRs), one of the most important classes of membrane proteins that are targeted by an extensive and diverse collection of external stimuli. Recently we learned that different ligands targeting the same GPCR can elicit different biological responses, but the mechanisms remain unknown. We address this fundamental question for the serotonin 5-HT2A receptor, because it is known to respond to the binding of structurally diverse ligands by producing similar stimuli in the cell, and to the binding of quite similar ligands with dramatically different responses. Molecular dynamics simulations of molecular models of the serotonin 5-HT2A receptor in complex with pharmacologically distinct ligands show the dynamic rearrangements of the receptor molecule to be different for these ligands, and the nature and extents of the rearrangements reflect the known pharmacological properties of the ligands as full, partial or inverse activators of the receptor. The different rearrangements of the receptor molecule are shown to produce different rearrangements of the surrounding membrane, a remodeling of the environment that can have differential ligand-determined effects on receptor function and association in the cell's membrane.
### Introduction
Serotonin 2A receptors (5-HT2AR) are a very well characterized family of G-protein coupled receptors (GPCRs) in the amine sub-class of rhodopsin-like class A GPCRs [1], [2]. The 5-HT2ARs are targeted by chemically and pharmacologically distinct classes of ligands which include antidepressants, anxiolytics, antiemetics, antipsychotics and anti-migraine agents. Notably, some agonists exhibit hallucinogenic properties [2], [3] that have been attributed to specific manners of activation of these receptors [4], [5]. Even when they share key structural features, such as the indole moiety of the non-hallucinogen 5-HT and the hallucinogen LSD, the 5-HT2AR ligands have been shown to be able to bind differently to the receptor molecule, and to exhibit different pharmacological properties [2], [6], [7], [8]. Understanding the relation between the different modes of binding of structurally diverse compounds in the 5-HT2AR binding site, and the pharmacological responses they elicit, has therefore been of great interest in the quest for understanding the function of the 5-HT2AR and especially its role in hallucinogenesis [5]. Important clues came from in vivo studies demonstrating that behavioral responses to different 5-HT2AR ligands correlate with distinct transcriptome fingerprints for the ligands [4]. However, while it remains unclear how ligand binding induces distinct conformational states of the 5-HT2AR, and how this can result in different pharmacological outcomes [5], the significant variability in receptor conformations that can be induced by different ligands has recently been demonstrated for the cognate β2-adrenergic receptor [9].
Structural evidence for differential effects of the GPCR ligands in relation to receptor function should be reflected in the variability of rearrangements in the key structural elements involved in the various activation states of the receptors, e.g., the structural motifs/functional microdomains (SM/FMs) [10] (see Figure 1A) that characterize GPCR activation [5], [11], [12], [13]. Specific SM/FMs have been reported from studies of a large variety of GPCRs [10], [14], [15], [16], [17], and their dynamic signatures include (i)-the flipping of the toggle switch W6.48 (Trp336, identified here by the Ballesteros-Weinstein generic numbering [18]) in the cluster of conserved aromatic residues in TM5 and TM6, (ii)-the opening/closing of the ionic lock between the DRY motif (D3.49–R3.50–Y3.51) and E6.30, involved in the movement of the intracellular (IC) end of TM6 away from TM3, and (iii)-the dynamics of the conserved NPxxY motif at the IC end of TM7 that connects as well to H8. These are elements of activation common to many GPCRs (see [5], [10], [11], [13], [14], [15], [16], [17], [19]), and their status in the X-ray structures of various GPCRs has been evaluated [12], [20], [21], [22], [23], [24], [25]. It is still unclear, however, how the binding of different ligands affects these elements of GPCR activation and how they connect to the mechanisms of the ligand-driven receptor oligomerization that has been shown to be critical for GPCR function [26], [27], [28], [29], [30], [31].
To shed new light on these central mechanistic questions from the perspective of ligand-dependent conformational states involved in the activation and oligomerization of GPCRs in their membrane environment, we performed large-scale molecular dynamics (MD) simulations of 5-HT2AR in complex with ligands exhibiting different pharmacological properties: the full agonist 5-HT, the partial agonist LSD, and the inverse agonist Ketanserin (KET) (Figure 2A). The simulation results show that the three ligands affect differently the dynamics of SM/FMs monitored in the simulations (Figure 1B), which achieve distinct conformations that are consistent with the pharmacological classification of these ligands. Moreover, the simulations show that the ligand-bound GPCRs produce differential responses in the lipid membrane surrounding the receptor, as reflected in the spatial pattern of the remodeling of membrane thickness. These trajectories reveal as well the modes and effects of direct receptor-cholesterol interaction. Recently we have described the development and implementation of a new method, CTMD (Combined conTinuum and Molecular Dynamics), for quantitative analysis of the membrane remodeling pattern based on MD trajectories [32]. With this method we account for both the membrane remodeling energy and the energy cost of any partial (incomplete) alleviation of the hydrophobic mismatch by this remodeling of the membrane. From the quantitative analysis with CTMD of the simulation results for the monomeric 5-HT2AR we identified ligand-specific local membrane perturbations that can produce different patterns of 5-HT2AR oligomerization driven by hydrophobic mismatch [32]. Our results lead to the prediction that the dimerization interfaces for 5-HT2AR oligomers will be different when the receptor binds ligands with different pharmacological properties (inverse agonist, partial agonist, or agonist), as suggested earlier [27]. Notably, the extent of membrane-driven oligomerization of a 5-HT2AR in the inverse agonist-bound state is predicted to be larger than in the agonist-bound state. These predictions are consistent with previous experimental findings on cognate GPCRs [27], [28], [31], supporting the link we identify here between ligand-dependent conformational changes in GPCRs and differences in local membrane perturbations.
### Results
#### Agonist-determined dynamics are expressed as an ordered sequence of changes in the SM/FMs of ligand-bound 5-HT2AR
The main dynamic rearrangements observed in the simulations of the 5-HT2AR when it binds each of the ligands, are described below with reference to the SM/FMs (Figure 1A) identified in this family of GPCRs [5]. The sequential order of the description is determined by the order in which these changes appear in the simulation trajectories of the 5-HT2AR bound to the full agonist 5-HT (Figure 1B).
##### TM6 and the ionic lock.
Figure 1 illustrates the known structural characteristics of GPCR activation and the time-ordered sequence of their occurrence in the simulation of the 5-HT-bound 5-HT2AR. The time-dependent changes in these SM/FMs are detailed in Figure 3. During the initial stages of the simulation, the changes in the orientation of the TM6 segments (before and after the Proline-kink) cause the bend to straighten out (Figure 3A) and the extracellular (EC) end of TM6 to move toward TM3 (Figure 3B and G). This is consistent with a conformational change observed in the crystal structure of β2AR [25] as well as in experiments [33] associated with β2AR activation. It is interesting to note that the change in bend angle around P6.50, from 33.2 in the inactive β2AR (2RH1_chain A) to 25.9 in the active β2AR (3SN6_chain R), is consistent with the first changes observed in the simulation of 5-HT-bound 5-HT2AR (Figure 3). In addition, the ionic lock (between the DRY motif on the IC end of TM3 and E6.30) changes as shown in Figure 3E: it equilibrates first into a closed form, but in later stages of the trajectory switches back to an open form compatible with the expected agonist-activated conformation; the IC end of TM6 moves away from TM3 (Figure 3D, I). This is remarkable because of the opening of the ionic lock between the DRY motif and E6.30 is a landmark of GPCR activation [10], [34], [35], [36], [37], and the broken ionic lock is evident in an active β2AR structure stabilized by nanobody [23] as well as an agonist-bound β2AR in complex with the nucleotide free Gs heterotrimer [25].
##### The aromatic cluster.
From the trajectory, the opening of the ionic lock (Figure 3E) and the movement of the IC end of TM6 (Figure 3D) appear to relate to the rotamer flip of W6.48 from its orientation near-perpendicular to the membrane plane, to a near-parallel one (Figure 3C, J). Such a conformational switch in W6.48 upon GPCR activation has been reported from a variety of experimental studies [36], [38], and is observed near the 140 ns time point in the trajectory when the χ1 angle of W6.48 changes from g- to trans (Figures 1B,3C,3J). When the ring of W6.48 remains parallel to the bilayer for ~1 ns it forms a double pi-pi interaction with both F6.44 and F6.51 (see Figure S1 in Text S1). This may facilitate the change in TM6 kink around P6.50 as suggested earlier [39] which would thus support the opening of the ionic lock by increasing the distance between the IC ends of TM6 and TM3 (Figure 3D).
##### The NPxxY motif and helix 8.
During the first 50 ns of the agonist-bound 5-HT2AR simulation, the conserved NPxxY motif at the IC end of TM7 changes its conformation and spatial relation to H8 (Figure 3F). The dynamics in this SM/FM have been related to GPCR activation [19], [22]. In particular, the interdependence of residues at positions 7.53 and 7.60 in the NPxxY sequence has been suggested to modulate the transition to the active state in the serotonin 2C receptor (5-HT2CR) [24], and structural data show that the pi-pi interaction between 7.53 and 7.60 (Figure 1A) seen in inactive structures, is disrupted in active structures of β2AR stabilized by nanobody [23], or complexed with the Gs heterotrimer [25]. In addition, the Cα distances between 7.53 and 7.60 in these active structures are larger (9.6 ???) than those in inactive ones (6.3 ???). The opening of the TM7-H8 angle is consistent with the transition to activated states of other GPCRs [22], and here we find that, in the 5-HT-bound 5-HT2AR, H8 moves away from TM7 and the distance between the Cα atoms of Y7.53 and Y7.60 increases from ~6.2 ??? during the first 50 ns, to a value of 8 Å that remains stable for the remainder of the trajectory (Figure 3F).
Taken together, this sequence of steps observed in our simulations of 5-HT2AR in complex with 5-HT ( Figure 1B ) not only captures structural effects of agonist binding on the status of the SM/FMs, but also provides a mechanistically understandable hypothesis for this ordered sequence of apparently interrelated conformational changes that bring the 5-HT-bound 5-HT2AR in line with known features of the activated state.
#### Significant differences are evident in the dynamics of the same SM/FMs in 5-HT2AR bound to either the partial agonist LSD or the inverse agonist KET
Comparison of results in Figure 4 with Figure 3 brings to light the differences among the dynamic mechanisms connected with the binding of the three different ligands to the 5-HT2AR, as detailed below.
##### KET bound to the 5-HT2AR.
In the KET simulation, the initially open ionic lock closes around 200 ns, and remains closed for the remainder of the trajectory, as the Cα distance between R3.50 and E6.30 residues stabilizes below 9 Å (Figure 4D, right panel), i.e., at a value consistent with inactive conformations of cognate GPCRs [40]. Similarly consistent with a preference for this SM/FM in an inactive form of the receptor, is the observation in KET-bound 5-HT2AR that neither the bend angle in TM6 (Figure 4A, right panel), nor the rotamer status of W6.48 (Figure 4C, right panel), change as they were seen to do in the trajectory of the 5-HT-bound receptor (Figure 3A, 3C). Thus, TM6 is more kinked with KET in the binding site than with 5-HT bound in the 5-HT2AR, but no movement of the EC end of TM6 is observed relative to TM3 (Figure 4B, right panel). This is in sharp contrast to the behavior of 5-HT-bound receptor (Figure 3B), where significant changes in these activation elements were observed. Further, the dynamics of the NPxxY motif is also different in the KET-bound receptor, with the TM7-H8 pair maintaining a tighter conformation, and the Y7.53-Y7.60 Cα distance stabilized at ~6 Å for the later part of the trajectory (Figure 4E), i.e., 2 Å shorter than that in 5-HT2AR complexed with 5-HT (Figure 3F). Note that such close proximity of the Y7.53 and Y7.60 residues has been suggested as a characteristic of an inactive state in GPCRs [41].
To validate the inferences from the KET simulation, and verify the distinctions between the agonist-bound and inverse-agonist bound forms of the 5-HT2AR, we tested whether the binding of the inverse agonist KET would reverse the effect of the full agonist 5-HT on the conformational state of the serotonin receptor. To this end, we used the 5-HT-bound 5-HT2AR structure (from the average over the 300–350 ns trajectory interval of the simulation) as a starting structure for a new 500 ns simulation in which KET was substituted for the 5-HT (termed, KET-substituted, see Methods). As illustrated in Figure 5A, at ~240 ns into this new trajectory, the ionic lock that had opened in the agonist-bound simulation started to close when KET replaced it (the E6.30–R3.50 Cα distance decreased below 9 Å), and D3.49 and R3.50 formed a salt-bridged H-bond. Furthermore, from the same time point onwards, the structure of the TM bundle gradually became more similar to that stabilized by KET (the backbone TM RMSD relative to the KET-stabilized structure decreased by ~0.5 Å; Figure 5A).
These results show that the SM/FMs in the 5-HT2AR bound to KET adopt characteristics observed in inactive GPCR states, which differ significantly from the ones observed with 5-HT in the binding site. This observation is in line with the opposite pharmacological properties of these two ligands.
##### LSD bound to the 5-HT2AR.
As shown in Figure 4 (left panel), the dynamic behavior of the LSD-bound receptor is in line with the pharmacological efficacy of LSD as a partial agonist, i.e., intermediate between those observed for the 5-HT- and KET-bound 5-HT2AR constructs. Thus, in the LSD-bound receptor the ionic lock transitions between open and closed conformations (Figure 4D, left panel), as the R3.50–E6.30 distance fluctuates in the range of values proposed [40] for open (>9 Å) and closed (<9 Å) ionic lock states. In the NPxxY motif region, the Y7.53–Y7.60 distance in the LSD-bound receptor remains in the range associated with an open conformation throughout the trajectory, similar to that in the 5-HT bound receptor (cf. Figures 3F and 4E). The bend angle around P6.50 in the LSD-bound receptor decreases from 35° to 15° (Figure 4A, left panel) with the EC end of TM6 bending towards the center of the protein bundle. However, the extracellular segment of TM6 does not come as close to TM3 as it does in the 5-HT simulation (cf. D3.32-F6.52 and D3.32-N6.55 in Figure 3B and Figure 4B, left panel).
Consistent with the incomplete opening of the ionic lock, the time-trace of the tilt angle of the W6.48 aromatic ring in LSD trajectory (Figure 4C, left panel) indicates as well that the dynamics of the toggle switch is intermediate: the complete flipping of W6.48, observed in the 5-HT simulation (Figures 3C, 3J), is replaced here by significant fluctuations in W6.48 orientation compared to the KET-bound 5-HT2AR (Figure 4C, right panel). Thus, in monitoring the steps in the dynamic sequence we find for the partial agonist LSD a series of intermediate dynamic modes that turn on the SM/FM forms associated with an active conformation, but not necessarily all of them together (e.g., the TM7-H8 angle is wider, and the ionic lock is broken, but with a fluctuating, not flipped W6.48). Like the other two ligand types, the pattern generated by LSD is entirely consistent with its known pharmacological property.
#### The 5-HT2AR in complex with either 5-HT, LSD, or KET visits distinct conformational spaces
The nature of similarities and differences observed in the dynamics of the 5-HT2AR when it binds each of the three ligands was further evaluated with Combined Essential Dynamics (Comb-ED, see Methods) [42] performed on concatenated trajectories for 5-HT&LSD, 5-HT&KET, and LSD&KET, each combining the last 100 ns of the individual trajectories for the pair. The comparison of such combined trajectories by their projection along their first and second eigenvectors is shown in Figure 6A, which illustrates the differences in the conformational spaces sampled by the 5-HT2AR bound to different ligands. Clearly, along the first eigenvector, the conformational spaces sampled by the 5-HT-bound and LSD-bound receptor are seen to be more similar to each other than either one is to the space sampled by KET-bound 5-HT2AR (note that the first and second eigenvectors are different in each plot because the concatenated trajectories differ, so that the sampled spaces shown in the plots for any one ligand-bound receptor appear at different positions).
The comparison in Figure 6B–C shows the differences in a structural context by indicating where the largest differences occur, as monitored by the magnitudes of the projections on the first eigenvectors (color coded from red, green to blue representing magnitudes from large, median to small, respectively). Also evident in this figure is the greater similarity between the dynamics of the 5-HT and LSD-bound receptors (Figure 6B–C, top panel). Comb-ED analysis identifies only insignificant differences between the agonist- vs. partial agonist-bound states of the receptor, with some variations in the positioning of the juxta-membrane H8 and in TM4 (Figure 6B–C, top panel). However, the structure of 5-HT2AR in complex with either 5-HT or LSD is clearly distinct from that with KET bound, as seen in Figure 6B–C where the Comb-ED detects differences in TM5–6 (linked by IL3) and TM4 in the 5-HT vs. KET comparison (middle panel), and LSD vs. KET (bottom panel).
Differences between 5-HT2AR complexes with the inverse agonist, and those with the agonists 5-HT or LSD, are apparent as well for TM1, TM3 and H8 (Figure 6B–C, middle and bottom panels). Thus, in the KET-bound receptor, Comb-ED identifies the movement of TM5 and TM6 toward TM3 at the IC end, consistent with the observed closing of the ionic lock in the inverse agonist state (Figure 4D,F, right panel). Furthermore, differences are evident at the EC end of TM6 between KET- and 5-HT-induced conformations, in agreement with the different level of kink in TM6 around the P6.50 in the two systems (compare Figures 3A and 4A). In addition, in line with the observed differences in the dynamics of NPxxY motif (Figures 3F and 4E), the Comb-ED analysis in the KET-bound receptor detects the motion of H8 toward TM7 to close the angle between them, consistent with earlier studies of cognate GPCRs [22], [37], [43].
Based on the Comb-ED results suggesting structural differences as well in TM1 and TM4 between the states of 5-HT2AR stabilized by the three ligands (Figure 6B–C), we found different levels of tilt in TM1 and TM4 in the three states of the receptor. Thus, in 5-HT, LSD, and KET trajectories TM4 forms angles of 12°, 16° and 22°, respectively, with the membrane normal z axis; TM1 tilts so that in KET-bound compared to 5-HT-bound receptors its EC end is 3 Å closer to TM7 and its IC side is 1.5 Å farther from TM7. The differences in conformational changes of TM1 are consistent with the available X-ray structures of the activated GPCR, where a repositioning of the IC end of TM7 towards TM1 is reported in active β2AR [23] and opsin structures [20], [21]. As discussed below, these tilt differences in TM1 and TM4 are reflected in the response of the membrane to the interaction with the protein, and thereby can affect the ligand-regulated oligomerization of the 5-HT2AR.
The nature of the changes occurring in the transition from the “activated” 5-HT-bound state of the receptor, to the KET-bound “inactivated” state, is evidenced by the application of Comb-ED analysis to combined trajectories involving the KET-substituted simulation (started from an equilibrated 5-HT-bound receptor) (Figure 5B). Separately, two Comb-ED analysis were performed: One comparing the last 100 ns from the KET-substituted and the original KET-bound simulations, and the other comparing the KET-substituted and the 5-HT-bound simulation. The projections along the first eigenvector of these combined trajectories (Figure 5B) reveal the internal consistency of the results and show that, upon KET substitution, the 5-HT2AR structure deviated from the 5-HT-stabilized conformation and became similar to that stabilized by KET in our earlier simulation, with TM4 and TM6 helices changing the most. Consistent with the results in Figure 6, in the KET-substituted simulation the IC end of TM6 moved towards TM3, and TM4 became tilted.
In addition to Comb-ED analysis of pair-wise concatenated trajectories, we applied Comb-ED as well to all four trajectories (5-HT, LSD, KET, KET-substituted) concatenated together. The results (Figure S3 in Text S1) clearly show that KET-substitution transitions the receptor from the conformational states visited by 5-HT to those most visited when KET is bound in the receptor.
#### Ligand-dependent conformational changes in the receptor elicit corresponding structural re-arrangements in the surrounding lipid membrane
From the results of the comparative simulations we have identified two mechanisms of membrane re-organization in response to the conformational changes associated with the dynamics of the ligand-bound receptor: (i)-the direct interactions of the receptor with the Cholesterol (Chol) constituent of the membrane, and (ii)-the deformation of the membrane around the GPCR, which modulates the local thickness of the bilayer and the hydrophobic mismatch that can drive oligomerization of the 5-HT2AR [32].
##### Cholesterol interacts with the structural elements of GPCR activation.
Cholesterol has been implicated in GPCR function and activation [44] and shown to bind to preferred sites of rhodopsin in extended simulations of this GPCR in lipid membranes [43]. Here we found that the regions ranked highest in Chol population during the simulation of the 5-HT2AR were the IC end of a TM bundle including TMs 1, 2 and 4; the EC ends of TMs 2 and 3; and the EC and IC ends of TMs 6 and 7 (see Table S1 in Text S1). Notably, these sites were also found to be the areas of high Chol-density in earlier studies on rhodopsin [43], [45], [46], as well as in a 250 ns simulation of rhodopsin in a membrane with the same lipid composition as used here (SDPC/POPC/Chol - see [32]). We hypothesized, therefore, that Chol binding at these preferred locations may have some functional importance observable through effects on the monitored SM/FMs. Given the prominent structural changes in TM6 observed in our simulations of the 5-HT-bound 5-HT2AR, this hypothesis was investigated for Chol at the IC and EC ends of TMs 6 and 7.
Figure 7 summarizes Chol dynamics around the EC and IC ends of TMs 6 and 7, and its relation to the activation elements in 5-HT-bound receptor. The Chol at the EC end of TM6 is seen to be in direct contact with residues M6.57, I6.60, and C6.61 at the initial stages of the simulation (Figure 7A, upper panel), and to move away from these residues within the first 40 ns (Figure 7B). Interestingly, during the same time interval, we observe changes in one of the identified SM/FMs, as TM6 straightens out at the EC end, and starts moving towards TM3 (cf. Figures 23). Near the 140 ns time-point, another Chol, initially in contact with the IC end of TM7, moves towards TM6 and establishes interactions with residues K6.35, I6.39, F6.42 and V6.46 (Figure 7A, middle and lower panels, and Figure 7C). Remarkably, this shift of Chol away from TM7 and toward TM6 coincides with the time when the toggle switch W6.48 flips (Figures 23), and TM6 starts to bend away from TM3 at the IC end (Figures 23). Thus, the time dependence of Chol dynamics at the IC and EC ends of TM6 suggests its participation in the development of the activated conformation in the agonist-bound 5-HT2AR.
To quantify the apparent correlation between the Chol dynamics and the structural changes in the 5-HT/5-HT2AR simulation we calculated the Pearson correlation coefficients between the dynamic quantities presented in Figures 3 and 7, and constructed the matrix of the corresponding Pearson R2 scores following a protocol described earlier [43]. The strong correlation between Chol-TM6 distances and agonist-induced changes in 5-HT2AR is evident from the high values of the correlation coefficients (Figure 7D) calculated for the MD trajectory.
Notably, the pattern of Chol-GPCR interactions around TM6 in the 5-HT/5-HT2AR trajectory is different from those observed in either the LSD-bound or the KET-bound receptor. For example, analysis of the KET simulation shows a single Chol around the IC ends of TM5 and TM6 (Table S1 and Figure S4 in Text S1). This Chol molecule is engaged in interactions with F6.42 and V6.46, the same two residues of TM6 that we found to interact as well with Chol in the 5-HT trajectory (see Figure 7). But in contrast to the 5-HT simulation, the cholesterol positioned near the IC end of TM6 in the KET trajectory is also in contact with residues from TM5: F5.59 and I5.62. The specificity of these interactions is suggested by the observation that in the KET-substitution simulation (initiated from the 5-HT-induced conformation of the receptor), Chol interactions rearrange to the pattern observed in the regular KET simulation. Thus, in the KET-substitution simulation Chol still interacts initially with F6.42, V6.46, and I6.39, but when the ionic lock starts to form, F6.42 flips (without loosing contact with the cholesterol) towards TM5 and establishes stable interactions with F5.59 that brings TM5 and TM6 helices together from the IC side. Similarly, in the KET simulation, cholesterol near TM5 and TM6 appears as well to bring these two helices together by forming a bridge between F6.42 and F5.59.
When considered together with the ionic lock data ( Figure 4 ), these results suggest an active involvement of cholesterol near the IC end of TM6 in establishing differential ligand-induced conformational dynamics of the receptor.
#### Membrane shape exhibits distinct patterns in response to the 5-HT2AR conformations attained by pharmacologically different ligands
The distinct conformational changes in the receptor produced by the binding of the different ligands (see above) produce different patterns of bilayer deformations around the receptor protein in complex with the different ligands (Figure 8). This difference is a result of the tendency of the lipids to minimize the hydrophobic mismatch at various TMs, i.e., the difference in the hydrophobic lengths presented to the membrane by the corresponding TMs in the different receptor complexes (see detailed discussion in [32]). Therefore, hydrophobic thickness profiles of membranes around 5-HT2AR in the simulated complexes with 5-HT, LSD, and KET, shown in Figure 8, reveal remarkable differences in the membrane organization around individual TMs in the three systems. For example, the membrane appears thinner around TM4 and TM6 in 5-HT (left panel) than in the KET simulation (right panel), whereas at TM1 the bilayer is thicker in the LSD (middle panel) than in the complexes with 5-HT or the KET.
We have developed a quantitative method (CTMD), for the analysis of such membrane deformations and the significant residual exposure to unfavorable hydrophobic-hydrophilic interactions at specific TMs that results from an incomplete alleviation of the hydrophobic mismatch [32]. When applied to the 5-HT2AR complexes discussed here, residual exposure [32] was found at TM4 for all three complexes, although the values were different possibly because the TM4 tilt is different in the KET, LSD and 5-HT trajectories (see above). Because the extent of the hydrophobic mismatch around the TM helices is considered to be a driving force for oligomerization [32], , we had compared the residual exposure energies at all TMs in the simulation results for the three complexes. At TM1 it was found to be substantial only in the KET simulation, consistent with the conformational changes we observed for TM1 in different systems (see above), and at TM5 it appeared to be relatively similar in all three complexes, but somewhat more pronounced in the 5-HT-bound structure; lastly, the residual exposure at TM6 is largest as well in the 5-HT trajectory, possibly due to the relatively straighter configuration of this helix in the 5-HT simulation (Figures 34). One possible mechanism to reduce the energy penalty for this residual exposure in the membrane-embedded receptor conformation produced by the binding of a particular ligand, is to bring together the TM domains where the residual exposure is largest. Therefore, we proposed [32] that this represents a membrane-determined energy drive for the association of the proteins in the membrane.
Consequently, our data in Table 2 of [32] suggests that if the hydrophobic mismatch is the driving force for receptor oligomerization, then the contact interfaces for oligomerization of the 5-HT2AR will be different in the complexes with 5-HT, LSD, or KET. According to this mechanism, ligands will not only regulate the extent of GPCR oligomerization, but will also influence which TM domains constitute the oligomerization interface. Thus, a comparison of residual surface area values at different TMs in 5-HT, LSD, and KET simulations implicates TM1, TM4 and TM5 as likely participants in the oligomerization interface of 5-HT2AR in complex with KET, TM4 and TM5 in the oligomerization interface of LSD-bound receptors, and TM5 (and possibly TM6, TM4 and TM2 as well) as the most likely participants in the oligomerization of 5-HT-bound serotonin receptor.
In addition, the results in Table 2 of [32] for the 5-HT and KET simulations imply that overall the inverse agonist KET will promote more extensive hydrophobic mismatch-driven oligomerization, since the residual surface area value summed over all TMs is about 90 Å2 higher for KET-bound 5-HT2AR than it is for 5-HT-bound receptor. This prediction is in excellent agreement with the experimental data on ligand-regulated oligomerization on β2AR [31], where in comparison to the agonist isoproterenol, the binding of an inverse agonist was suggested to promote tighter packing on β2AR protomers and/or to result in formation of higher-order oligomeric structures.
With regard to the validation of the ligand-dependent dynamic properties, it is important to note that similar residual exposure is observed in the two KET-bound simulations starting from very different initial conformations. Thus, the trend of large residual exposures at TM1, TM4, and TM5 of the KET system is also observed in the KET-substituted system (Table S3 in Text S1). Moreover, near the TMs where the hydrophobic mismatch is alleviated by the membrane remodeling (e.g., TM6), the membrane has similar thickness in both the KET and KET-substituted system (Figure S6 in Text S1).
### Discussion
The MD simulations of the 5-HT-, LSD- and KET-bound 5-HT2AR reported here provide the first molecular representation of the different effects that pharmacologically distinct ligands can have on the 5-HT2AR. The concepts of “functional selectivity” [49], [50] and “receptor bias” [51] are frequently being used to explain the increasingly common observation of differential responses elicited by different ligands from the same receptor (e.g., for 5-HT2AR see [4], [52]). However, no structural context had been identified for the distinct effects on the dynamics produced in the same GPCR by the binding of pharmacologically different ligands. Here we simulated the dynamics of the 5-HT2AR binding of such pharmacologically distinct ligands, and identified different effects on the SM/FMs of the receptor. These effects were shown to lead to different rearrangements that correspond to the different levels of activation known to be produced by these ligands. Notably, the differential effects were shown to be consonant with the pharmacological characterization of the three ligands as a full, partial and inverse agonist, respectively. To our knowledge, such inferences were obtained for the first time here from unbiased atomic MD simulations, but they are in line with the increasingly detailed experimental evidence about ligand-related functional selectivity [49], [50], [51], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], with the proposals of ligand-selective conformations in the 5-HT2AR [67] and the D2R [68], and with structural data indicating that GPCRs such as β2AR are stabilized in distinct conformational states by inverse, partial, or full agonists - respectively [12], [13].
In the current simulations, structural changes associated with SM/FM characteristics of an “activated state” of the 5-HT2AR appear in sub-microsecond trajectories. In contrast, experimentally determined GPCR activation timescales generally vary from microseconds (photoactivation of rhodopsin [69]) to seconds (β2AR in living cells [70]). We emphasize that the conclusions reached here do not require the simulations to have converged to an “active state structure” of the kind claimed for the constructs determined crystallographically. Indeed, a number of modes of activation proposed from experiment share this characteristic and can also be significantly faster [71], [72], [73]. But in general, there are many reasons for the time scale differences between our results and functional measurements. In particular, the simulated system is an idealized construct in that all interaction components are placed in optimal positions to be at or near their targets. Titratable groups are also assigned their final charge states, e.g., when the D3.49 and E6.30 are in the protonated form in some of the constructs. Interestingly, the specific protonation form does not determine whether the ionic lock is formed or not (see Figures 34, and Figure S5 in Text S1); rather, the determinant factor is seen from our results to be the nature of the dynamics induced by the binding of a specific ligand. But considering that inactive GPCR (β2AR) may be pre-coupled to G-protein Gs [31] and the protonation of E3.49 in rhodopsin (an activation step) depends on transducin [74], the degree of precoupling will likely play a role in the activation time. Moreover, the simulation conditions (such as pH, salt, lipid composition, and crowding) certainly do not mimic completely those surrounding the receptor in living cells (e.g., it is known that the highly flexible DHA chain of SDPC, included in the lipid mixture used here, facilitates GPCR activation [75]), and similar time-scale differences have been observed between computer simulations and experiments for other GPCRs [76], [77].
The response of the membrane environment to the different ligand-induced structural re-arrangements produces a reorganization of the membrane around the receptor. This is reflected in (i)-the involvement of Chol in direct interactions with the protein [43], [78], that was shown here to affect the dynamics of the SM/FMs, and (ii)-the membrane deformations around the TM bundle of a GPCR [48], [79], described here with the use of the CTMD method [32]. Because the different ligand-determined conformational changes in 5-HT2AR establish different patterns of local perturbations in membrane structure around the receptor complex, they were suggested to promote different ligand-dependent receptor oligomerization patterns through the hydrophobic mismatch between the TMs and the surrounding membrane [32]. This is supported by observations in the literature that: (i)- oligomeric associations of the dopamine D2R [27], 5-HT2CR [28], and the β2AR [31] is ligand-sensitive; and (ii)- GPCR self-assembly is regulated by the mismatch between the hydrophobic length of the TM segments of GPCRs and the hydrophobic thickness of the lipid bilayer, as suggested by both experimental results [80] and computational studies for rhodopsin [32], [48], [79]. Along these lines, the results presented here suggest that the dimerization interfaces of 5-HT2AR oligomers will be different for inverse agonist-, partial agonist-, or agonist-bound complexes, and moreover that the inverse agonist KET would promote more extensive 5-HT2AR oligomerization than the full agonist (5-HT). We note that these experimentally testable predictions regarding possible oligomerization interfaces were obtained by analyzing monomeric GPCRs in complex with different ligands, without the need to simulate the dimers or higher oligomers.
### Methods
#### Construction of the simulated systems
Several model systems of the serotonin 5-HT2AR receptor were studied with all-atom MD simulations in explicit models of the hydrated lipid membrane environment. The 5-HT2AR was simulated in complex with three ligands known to exhibit different pharmacological efficacies: the full agonist 5-HT, the partial agonist LSD, and the inverse agonist KET (Figure 2A).
##### 5-HT2AR constructs.
For the simulation of 5-HT bound 5-HT2AR, the protein was modified twice, very slightly, in regions distal to the binding site and the SM/FMs. The original receptor construct had a specific truncation of IL3 so that it consisted of 296 residues, from H1.28 to D5.57 and from R6.21 to K7.73, with an Ala–Ala linker between them (H1.28–D5.75–AA–R6.21–K7.73, where “–” denotes truncation). To match observations in crystallographic structures of several GPCRs [20], [25], [81], we thus added, at 112.5 ns, four residues to the IL3 (H1.28–L5.79–AA–S6.17–K7.73) in order to extend helical parts of TM5 and TM6, respectively, by two turns. The extension was done as follows: an average structure of the protein (including the ligand and palmitoyl derivative) was obtained from the trajectory between from 83.5 to 112.5 ns. The averaged structure was minimized first with constrained protein backbone and ligand heteroatoms followed by minimization without constraints. To enhance the flexibility of the truncated IL3, we extended the intracellular ends of TM5 and TM6 by 2 turns of helix each using Modeller [82], and selected the representative model by clustering the 100 models using either the extended TM5 or TM6. The loop between the extended TM5 and TM6 was refined using Modeller. The protein with extended TM5 and TM6 together with the ligand and palmitoyl chain was minimized first with protein backbone and 5-HT heteroatoms constrained, followed by complete minimization. The minimized complex was inserted in the lipid/water/ion environment from the snapshot at 112.5 ns to conserve interactions, after which the entire system was minimized and equilibrated with constraints on the protein backbone (velocities were reassigned in a random distribution based on the temperature). For the second extension, at 174.2 ns (i.e., 61.7 ns after extending TM5 and TM6), we added three more residues at the N-terminus (S1.25–L5.79–AA–S6.17–K7.73) to allow TM1 to reach beyond the lipid phosphate group region of the model membrane so as to avoid artificial interactions between the positive N-terminus and negative phosphate groups in membrane lipids. In addition, the N-terminus was acetylated and the C-terminus was N-Methylamidated to further avoid charge-charge interactions between termini and lipids. The simulations were then continued and the results reported here are from the 350 ns trajectory. Note that the initial homology model of 5-HT2AR includes an artificially open “ionic lock” between residues R3.50 and E6.30 due to the use of the β2 adrenergic receptor (β2AR) template in the homology modeling [83]. In the β2AR X-ray structure [45] the ionic lock is broken due to the co-crystallized lysozyme, but has been shown to consistently reform in MD simulations of inactive β2AR without the lysozyme [40].
The simulations of LSD-bound and KET-bound 5-HT2AR, started from the same conformation as for the 5-HT bound 5-HT2AR except that they included the extensions from the very beginning. In addition, to test whether KET, as an inverse agonist, is capable of reversing the conformation induced by the bound agonist 5-HT, we substituted 5-HT with KET in the activated 5-HT2AR structure obtained at the end of the 5-HT simulation, and restarted that simulation with KET for an additional 500 ns (termed “KET-substituted simulation”). The protocol for this switch of ligand was as follows: (i)-An average structure (protein+5HT+palmitoyl chain) was generated using the last 50 ns of 5-HT simulations, and then minimized; (ii) 5HT was substituted by KET so that the docking pose of KET (Figure 2D, left panel) is aligned with the minimized average structure using backbone atoms of binding site residues: D3.32, S3.36, S5.42 and S5.46. The complex (protein+KET+palmityol chain) was minimized by fixing the heteroatoms of KET and constraining backbone atoms of the protein; (iii)-The minimized complex was combined with the lipid/water/ion environment from a snapshot at 350 ns of the 5-HT simulation, to conserve the interaction between the protein and the environment. Lipid/water/ion was minimized and then equilibrated. Finally the whole system was equilibrated by reducing constraints on protein backbone atoms and KET heteroatoms. Velocities were reassigned based on the temperature.
Residues D3.49 and E6.30 were protonated in the 5-HT and LSD simulations (see also Discussion section, above), and deprotonated in the KET simulations (including KET-substituted simulation). We note that the protonation state of the E6.30 residue does not affect the state of the ionic lock, as we show in the separate simulation of KET-bound 5-HT2AR where E6.30 residue is protonated (see Figure S5 in Text S1).
In all simulations, C7.70 was palmitoylated by moving the coordinates of the palmitoyl chain (PALM) from PDB 2RH1 [45] onto the C7.70 of 5-HT2AR.
##### Loop structures determined from ab inito loop prediction.
To enable full-scale 5-HT2AR simulations, we refined the loops in 5-HT2AR homology model described recently [83] using the Monte Carlo-Scaled Collective Variables ab initio method [84], [85]. For details see Methods and Table S2 in Text S1.
##### Initial placement of the ligands.
Protonated 5-HT, LSD and KET were docked into 5-HT2AR using several docking protocols, including Autodock 4 [86], Simulated Annealing-Docking [87], Glide (Schrödinger Inc.), and IFD (Schrödinger Inc.). In Autodock, the GA-LS algorithm and a maximum number of 2.5×107 evaluations were used. Simulated Annealing-Docking was carried out following a protocol previously established in our lab [87], [88] starting from a binding pose of 5-HT predicted by Autodock and consistent with experimental data. Glide [89] was carried out with and without H-bond constraints on D3.32 and/or S5.46. Applying H-bond constraints on S5.46 generated more docking poses that were consistent with the experimental data. IFD [90] was carried out starting either from scratch or from Glide docking poses that were consistent with experimental data. Other docking parameters were set to default values.
These procedures generated docking poses consistent with experimental data in the literature [2], [6], [7], [91], [92] (Figure 1A–D). In particular, for KET, IFD produced a cluster of docking poses in which the amines of the ligands interacted with D3.32 and S5.46, and its quinazoline ring immersed deep into the binding pocket close to W6.48. The binding site remained almost unchanged except that F6.52 rotated to avoid steric clashes with KET (Figure 1D). In this docking pose, which was used in the simulations, KET was in direct contact with the aromatic cluster (F5.47, F6.44, W6.48, F6.51 and F6.52) by forming an edge-to-face interaction with W6.48.
##### Internal waters.
X-ray structures of several GPCRs show water networks around the toggle switch W6.48 and the NPxxY motif [45], [93], [94], [95], and these are hypothesized to be important for receptor activation [96]. Internal waters were therefore introduced by solvating the 5-HT2AR with Grand-Canonical Ensemble simulations using the Monte Carlo program MMC [97]. The procedure placed waters around W6.48 and the NPxxY motif consistent with the X-ray structures of cognate GPCRs.
##### Lipid membrane composition and protein-membrane complex preparation.
The 5-HT2AR-ligand complexes were embedded in identical mixed and hydrated 7:7:6 1-stearoyl-2-docosa-hexaenoyl-sn-Glycero-3-phosphocholine(SDPC)/phosphatidylcholine (POPC)/Chol membranes. The choice of the lipid mixture was dictated by several factors: (i)-Chol is known to be important for modulating ligand binding, G-protein binding and activation of serotonin receptors [44], and has even been found in complex with the X-ray structures of amine GPCRs elucidated recently; (ii)-POPC represents a typical phospholipid component of the bilayer membrane, with one saturated and one mono-unsaturated acyl chain; and (iii)-SDPC lipid has been implicated specifically in the function of various GPCRs [98] and is abundant in neuronal tissues. In addition, the use of this lipid composition enables a comparison of Chol dynamics around 5-HT2AR with observations from earlier MD studies of rhodopsin in somewhat different Chol-containing mixed membranes [43].
The lipid bilayer model was generated using VMD [99] to construct first a 120 Å×120 Å (in the x-y plane) hydrated POPC membrane patch consisting of 406 lipids; then, half of the POPC lipids were transformed to SDPC by translating corresponding atoms, i.e., from the POPC headgroups to PCGL, from the 16:0 sn-1 chain to STEA, and from the 18:1 sn-2 tail to DHA (missing atoms were built using internal coordinates in the all-atom CHARMM27 force field [100] with CHARMM31b1 [101]). To reduce steric clashes between POPC and SDPC molecules, we made use of the relatively straight DHA chains from the equilibrated SDPC membrane bilayer (http://www.lipid.wabash.edu/), and replaced all the DHA chains in the current membrane patch with the straight DHAs. The 5-HT-, LSD-, or KET-bound 5-HT2AR were inserted into the lipid matrix by aligning the backbone of its seven most conserved residues (one in each TM, see [18]) with those of rhodopsin immersed in a POPC membrane [22]. Lipids within 0.8 Å of the protein and PALM were then removed leaving 354 lipids in total. 26 SDPC and 26 POPC in each leaflet were randomly replaced with Chol (PDB 3D4S [46]), by fitting Chol's C4, C5 and C6 atoms to STEA's C5, C6 and C7 or POPC's C35, C36 and C37. Chol positions were then refined by lateral translation to avoid clashes with other Chol, SDPC or POPC lipids. Finally, the systems were solvated with TIP3 water and 0.15 M NaCl salt. The final simulated systems consisted of 125 SDPC, 125 POPC, 104 Chol and 20–22K water molecules resulting in a total of 106–114K atoms.
#### Force-fields and MD simulations
The parameters for 5-HT were taken from an earlier study [7]. For LSD and KET, the results of geometry optimization and electrostatic potentials obtained from quantum mechanical calculations with the Gaussian program (Gaussian, Inc., Wallingford, CT) were used as input to the Restrained-ElectroStatic-Potential fit method [102] implemented in Antechamber [103] to derive charges. CHARMM topology and parameter files were then prepared with Antechamber using Restrained-ElectroStatic-Potential charges and GAFF force field. Force field parameter files for 5-HT, LSD and KET are included in Text S1. For protein, PALM, lipids etc., the all-atom CHARMM27 force field with CMAP corrections [100] was utilized (this approach is similar to a procedure used successfully in previous studies [104], [105]).
All MD simulations were performed with the NAnoscale Molecular Dynamics (NAMD) suite [106]. As established in similar studies in the lab (e.g., see [107]), the simulations were conducted under constant temperature and pressure conditions with anisotropic pressure coupling, and utilized PME for long-range electrostatics [108]. The Nose-Hoover Langevin piston method [106] was used to control the target pressure with the LangevinPistonPeriod set to 100 fs and LangevinPistonDecay set to 50 fs. All MD simulations were performed with rigidBonds allowing 2 fs time step.
All the simulated systems were equilibrated following a procedure described recently [109]. According to this protocol, the 5-HT2AR backbones and the heavy atoms of the ligands were initially fixed and then harmonically constrained, and water was prevented from penetrating the protein-lipid interface. Constraints were released gradually in four 300 ps-step MD simulations with decreasing force constants of 1, 0.5, 0.1 and 0.01 kcal/(mol·Å2), respectively. Following this equilibration phase, all three GPCR-membrane complexes were simulated for 350 ns.
The stability of the simulated complexes was monitored from the backbone RMSDs of the TMs in 5-HT2AR using the following definitions for TMs: L1.29–L1.59, A2.38–Y2.67, L3.24–N3.56, S4.38–V4.62, D5.35–K5.67, N6.29–I6.60, G7.32–F7.56 and K7.58–I7.68. As illustrated in Figure 1E, after initial equilibration, the RMSDs in all the three systems were stable and fluctuated around or below 2 Å. In all three simulations the ligands maintained key interactions with the receptor (Figure 1B–E), consistent with previous experimental data [2], [6], [7], [91], [92].
#### Analysis of MD trajectories
To quantify the changes in protein structure produced by the simulations we used various analysis tools. Analysis of protein structural data was carried out with Ptraj in AMBER 9 [110] and other tools discussed below. To quantify helix distortion parameters in the simulations, we used the Prokink package [111] implemented in Simulaid [112]. The correlation analysis on the time-dependent data of different variables, such as helix bend angles, face-shifts, as well as Chol-protein distances, was conducted following the procedure described in [43]. Briefly, the correlation analysis was carried out on two separate sets of dynamic variables. In the first, we followed the time-sequence of m = 8 selected variables that included proline kink and face-shift angles in TM6 and TM7, the minimum distances between the Chol at the EC end of TM6 and the residues on TM6 (I6.53, M6.57, I6.60, C6.61). In the second set, m = 12 dynamic variables were selected that included proline kink and face-shift angles in TM6 and TM7, the minimum distances between the Chol at the IC end of TM6–7 and the residues on TM6 and TM7 (K6.35, I6.39, F6.42, V6.46, L7.44, V7.48, V7.52, L7.55, F7.56).
For each set, we first studied pair-wise correlations between different variables, and constructed the matrix of coefficients of determination, R2 (Figure 7D of the main text) using Spearman's rank correlation test (see for instance Ref. [113]). In this method, given Nframes pairs of observations, (xi, yi), first the xi and yi values separately are assigned a rank, and then the corresponding difference, di between the xi and yi ranks is found for each pair. The R2 is then defined as:(1)
Because it uses rankings, Spearman's method eliminates the sensitivity of the correlation test to the function linking the pairs of values and thus is preferred over parametric tests when no a priori knowledge exists on the functional relationship between xi and yi pairs.
#### Combined Essential Dynamics (Comb-ED) analysis
To compare the conformational spaces of 5-HT2AR stabilized by the different ligands (i.e., 5-HT, LSD and KET), a Combined Essential Dynamics analysis [42], [114] was performed on Cα atoms of the protein using Gromacs 3.3 [115]. Essential dynamics analysis separates the configurational space into an essential subspace with a few degrees of freedom which describe overall motions of the protein that are likely to be relevant to its function, and a physically constrained subspace describing local fluctuations. The method is based on the diagonalization of the covariance matrix of atomic fluctuations defined by:(2)
where xi are the three Cartesian coordinates of the carbon atoms Cα of the molecule under study, and the angular brackets denote averages over an ensemble of configurations and over the simulation time. The diagonalization of Eq. (3) yields eigenvectors that describe the directions of correlated positional changes in the molecule, whereas the eigenvalues indicate the total mean square fluctuation along these directions.
In the Comb-ED, the covariance matrix is calculated for two or more concatenated trajectories, which are fitted on the same reference structure. Given this construct, the eigenvectors resulting from Comb-ED do not represent the essential degrees of motion of the molecules, but rather reveal differences and/or similarities in the dynamical and structural characteristics of the compared simulated structures. To identify structural differences between 5-HT2AR stabilized by the three ligands, Comb-ED analysis was performed on 3 concatenated trajectories obtained by combining the trajectories for the pairs 5-HT-LSD, 5-HT-KET, and LSD-KET, each for the last 100 ns, respectively.
##### Analysis of membrane deformations and the residual mismatch.
The properties of the membranes were analyzed from the simulation trajectories using the recently described CTMD method [32]. Briefly, to quantify membrane deformations in the simulations and the hydrophobic mismatch energies, we calculated the time-averaged hydrophobic thickness profile of the membrane surrounding 5-HT2AR in all trajectories and used solvent accessible surface area calculations to calculate the energy of the residual mismatch which exposes TM residues participating in unfavorable interfacial hydrophobic/hydrophilic interactions. To identify these residues, we determined if the TM is thicker or thinner than the surrounding membrane by comparing the hydrophobic thicknesses of the TM domains (using the following TM definitions (given in the Ballesteros-Weinstein generic numbering [18]): 1.29–1.59 (TM1), 2.38–2.67 (TM2), 3.24–3.53 (TM3), 4.39–4.63 (TM4), 5.38–5.63 (TM5), 6.33–6.59 (TM6), 7.30–7.56 (TM7)) to the local membrane thickness dmemb calculated from the membrane sectors corresponding to each TM, as described in [32].
### Supporting Information
Text S1.
Including supplemental methods, Figures S1, S2, S3, S4, S5, S6, Tables S1, S2, S3, Topology and parameter files for 5HT, LSD and KET.
doi:10.1371/journal.pcbi.1002473.s001
(DOC)
### Acknowledgments
We thank Dr. Junmei Wang for his assistance with the use of Antechamber.
### Author Contributions
Conceived and designed the experiments: JS GK SM HW. Performed the experiments: JS SM. Analyzed the data: JS GK SM ELM HW. Contributed reagents/materials/analysis tools: SM ELM. Wrote the paper: JS GK SM ELM HW.
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Ambra 2.10.6 Managed Colocation provided
by Internet Systems Consortium. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8554224371910095, "perplexity": 10431.021267399385}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1412037662910.19/warc/CC-MAIN-20140930004102-00081-ip-10-234-18-248.ec2.internal.warc.gz"} |
https://math.meta.stackexchange.com/questions/32950/strange-vertical-alignment-error-in-math-mode-text-in-the-related-questions-li | # Strange vertical alignment error in math mode text in the “Related Questions” list
This concerns the "Related Questions" list I can see tied to this question. A picture of the relevant link is below:
Notice how, in the $$(4,4)$$ ordered pair, the left $$4$$ is one pixel below the right $$4$$.
I originally thought this might be -- somehow -- tied to a custom command I used on the page to help make my answer, which was simply having \p render \propto. However, the error persisted, in a sense. Before removing my command, I instead had this issue, where every ordered pair except $$(4,4)$$ had the issue; removing the command made it affect only $$(4,4)$$ on my viewing:
Perhaps adding some lines will make the misalignment particularly clear:
Some other notes:
• This error does not seem to exist for me on Firefox. (The above pictures are tied to the newest version of Google Chrome; for what it's worth, I'm using Windows 10.)
• This error does apear on Microsoft Edge:
• This error does not seem to appear on other questions, e.g. this one.
• This error, I imagine, does not depend on browser extensions (I don't even use Edge).
• I bugged my girlfriend about it, and it does appear for her on Chrome (the variant affecting $$(4,4)$$ only), and appear for her on Edge, in the variant below. She uses Windows 10 as well for what it's worth. (Lines added by me because this variant was new.)
It's a minor error since, as far as I know, it's purely visual and hard to notice unless pointed out or if you're used to seeing such errors. Still, I figured it worth bringing up -- any idea what could be causing this? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 6, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7700093388557434, "perplexity": 1199.7494602773147}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038461619.53/warc/CC-MAIN-20210417162353-20210417192353-00219.warc.gz"} |
http://mathhelpforum.com/algebra/47434-integer-help.html | # Math Help - Integer help!
1. ## Integer help!
Thank you taking the time.
I need to write the expression in words that described the interval of numbers below.
(4,21/2)
3. Given that A = {x|x > 3} and B = {x|-3< x < 2}, express the following in interval notation. (The < has a line under it so it means equal to. I can't make it equal to.)
A U B interval ____________
A n B interval ____________
2. Originally Posted by Pangu
Thank you taking the time.
I need to write the expression in words that described the interval of numbers below.
(4,21/2)
3. Given that A = {x|x > 3} and B = {x|-3< x < 2}, express the following in interval notation. (The < has a line under it so it means equal to. I can't make it equal to.)
A U B interval ____________
A n B interval ____________
i can try this 3 u mentioned
A = {3,4,5,6....} - u mentioned > 3
B = {-3,-2,-1,1,2.3}
A u B ={-3,-2,-1,0,1,2,3,,4,5,6....}
A n B ={3} | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9510456323623657, "perplexity": 2079.0343973909344}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657129229.10/warc/CC-MAIN-20140914011209-00273-ip-10-196-40-205.us-west-1.compute.internal.warc.gz"} |
http://miind.sourceforge.net/page_installation.html | Miind
Installation
# Third Party Dependencies
It is recommended, but no longer necessary, to install ROOT. ROOT is a powerful analysis platform that has similar capabilities as MATLAB, but is optimized for high end performance. Under Unix systems, this is straightforward. For almost all UNIX-like distributions there is a binary. This can be installed in a directory of your choice. If you have sudo or root permission, you can opt to have ROOT installed under /usr/local, thereby making the framework available to all users. It is also possible to install the package locally. Regardless of whether you install the package locally or under /usr/local, the top of the ROOT directory structure is always a directory called 'root'.
Alternatively, you can compile the package from source, using the configure script} in the top directory of the download. There is a comprehensive description on how to do this: https://root.cern.ch/building-root. Make sure you have all the prerequisites installed that are listed at https://root.cern.ch/build-prerequisites.
Make sure that the version you use is configured with
--enable-python, --enable-table, --enable-mathmore
. You can use Python to inspect the simulation results, and convert them to numpy objects if you feel the need.
Whether you install ROOT locally or system-wide, make sure that the script root/bin/thisroot.sh is sourced, i.e. issue the command:
source ~/root/bin/thisroot.sh
if you have installed the package in your home directory. You have to do this every time before you use ROOT, so it is worth to include in a .bashrc file or equivalent.
If ROOT is not installed, it will produce ASCII files containing the firing rate.
You will also need:
• The GNU Scientific Library, GSL for short
• A recent (> 1.48) version of BOOST.
• FFTW3, the developer files.
section sec_procedure Procedure Whether you down load the tar file or checkout the code from the repository, you will have a top directory called 'miind-git'. This is the MIIND_ROOT. Where you place this is immaterial. Perform the following steps:
• Directly below 'code', create a directory called 'build'. This 'build' directory will be at the same level as 'apps' and 'libs'.
• 'cd build'
• 'ccmake ..'
• Indicate whether you want a Release or a Debug version, by setting the CMAKE_BUILD_TYPE field.
• You may have to indicate where ROOT is. CMake is intelligent enough to work out where, once you have provided the location of the root excutable.
• Configure ('c')
• Generate the Make file ('g')
• Quit ('q')
• Type 'make'
The libraries will built in build/libs, the excetuables in buid/apps. In general, you want set your PATH and PYTHONPATH such that they include the path to MIIND_ROOT/python.
CMake can be used directly from the command line, e.g.:
cmake path_to_miind_src -DENABLE_MPI=TRUE -DCMAKE_BUILD_TYPE=Debug -DMPIEXEC=/opt/local/bin/openmpirun
To compile the project type:
make
To build the documentation type:
make doc
# A Clean Ubuntu Install
We start with a clean Ubuntu 16-04 machine. Install the following packages with sudo apt-get install:
g++ (this should be at least g++ 5.4.0, which you should get by default.)
python-scipy
cmake-curses-gui
libboost-all-dev
libgsl-dev
libfftw3-dev
git
If you don't use ROOT, this is all you need.
Do not use a Ubuntu package for ROOT! It does exist, but misses a few libraries that MIIND depends on. Go to the ROOT web site: http://root.cern.ch, go to Download and click on the most recent version. Download the Ubuntu binary and unpack it in a directory of your choice. Issue the command
source cwd/root/bin/thisroot.sh
, where 'cwd' should be replaced by the name of the directory where you unpacked. If you now type 'root' anywhere in a shell, ROOT's CINT interpreter should start and a splash screen should appear. Exit CINT by typing ' .q'. Start a Python shell, and type 'import ROOT'. This module should now load without any comment. You may want to incorporate the 'source' command described above in a .bashrc file or equivalent. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.33437269926071167, "perplexity": 3536.184473342353}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-17/segments/1524125944848.33/warc/CC-MAIN-20180420233255-20180421013255-00351.warc.gz"} |
https://www.unige.ch/math/tggroup/doku.php?id=workshop | workshop
# Workshop "Real geometry in the footsteps of Gabriel Cramer"
Geneva, 2019 , October 28th - November 1st, Villa Battelle
Monday, October 28, 16:30, Battelle, Ilia Itenberg, “Planes in four-dimensional cubics”.
Tuesday, October 29, 11:45, Battelle, Nikita Kalinin, “Symplectic packing problem”.
Tuesday, October 29, 14:45, Battelle, Kristin Shaw, “Poincaré duality for tropical manifolds”.
Wednesday, October 30, 10:30, Battelle, Kristin Shaw, “Poincaré duality for tropical manifolds”.
Thursday, October 31, 14:30,Battelle, Kristin Shaw, “Poincaré duality for tropical manifolds”.
Thursday, October 31, 16:00, Battelle, Nikita Kalinin,“Symplectic packing problem and Nagata's conjecture”.
Friday, November 1, 15:00, Battelle, Nikita Kalinin, “Symplectic packing problem and Nagata's conjecture”.
Abstracts:
Ilia Itenberg (Sorbonne University)
Planes in four-dimensional cubics
We discuss possible numbers of 2-planes in a smooth cubic hypersurface in the 5-dimensional projective space. We show that, in the complex case, the maximal number of planes is 405, the maximum being realized by the Fermat cubic. In the real case, the maximal number of planes is 357.
The proofs deal with the period spaces of cubic hypersurfaces in the 5-dimensional complex projective space and are based on the global Torelli theorem and the surjectivity of the period map for these hypersurfaces, as well as on Nikulin's theory of discriminant forms.
Joint work with Alex Degtyarev and John Christian Ottem.
Kristin Shaw (University of Oslo)
Minicourse: Poincaré duality for tropical manifolds
The series of lectures will focus on the different formulations and approaches to Poincaré duality for the tropical homology group of tropical manifolds. Tropical homology is the homology of certain sheaves on polyhedral spaces and was introduced by Itenberg, Katzarkov, Mikhalkin, and Zharkov. The first formulation of tropical Poincaré duality was in terms of a non-degenerate pairing between compactly supported and usual tropical cohomology by Jell, Shaw, and Smacka. This pairing was formulated via the integration of superforms in the sense of Lagerberg. Tropical manifolds also satisfy a version of Poincaré duality for tropical (co)homology with integral coefficients by Jell, Rau, and Shaw. This version is formulated in terms of the cap product with the fundamental class. Another recent approach by Gross and Shokreih is via Verdier duality in the derived category and removes the assumption on the existence of a suitable covering of the tropical manifolds required in the two formulations above.
The proof of these duality statements in all three cases boils down to a local version of Poincaré duality for the tropical (co)homology of matroidal fans which is proved by using the deletion and contraction operations. The matroid property of a fan is sufficient but not necessary for tropical Poincaré duality. I will point out some partial results of Edvard Aksnes on necessary and sufficient conditions for tropical Poincaré duality for fans, and also highlight some consequences of Poincaré duality in the global case.
Nikita Kalinin (HSE University)
Talk 1: Symplectic packing problem. This will be an introductory talk. I will mention several instances of symplectic packing problems and present simple geometric methods for tackling them. Based on (unpublished) survey of Felix Schlink.
Talk 2: Symplectic packing problem and Nagata’s conjecture. Curiously, the question of what is the maximal R such that we can embed k<10 symplectic balls of radius R in CP^2 is related to the question of what is the minimal degree d of an algebraic curve in CP^2 passing through given generic points with given multiplicities. Nagata’s conjecture (still open for all n>10 except squares) states that d>m\sqrt n if we draw a curve through n points of multiplicity m. I will highlight the connections between symplectic packing and Nagata’s conjecture (based on works of McDuff, Polterovich, Biran, among others).
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https://www.nextgurukul.in/wiki/concept/cbse/class-6/english-grammar/conjunctions/conjunctions-of-contrast/3962872 | Conjunctions of Contrast
Contrastive conjunctions link two ideas that are considered to be different. Examples of contrastive conjunctions include: but, though, on the other hans, however, in contrast, on the contrary, instead, nevertheless, yet, still, even so, neither … nor. Example 1.The new city hall is amazing but it’s going to cost a lot. 2. He’s quite short, whereas his sister is tall. 3. Although I studied hard, I couldn't pass my English Exam. 4. Even though the government has taken up many literacy programs, literacy levels among 12-15 year olds do not appear to be improving. 5. No doubt, the use of elcetronic equipment has increased our standard of living. On the other hand, people has become very dependent.
#### Summary
Contrastive conjunctions link two ideas that are considered to be different. Examples of contrastive conjunctions include: but, though, on the other hans, however, in contrast, on the contrary, instead, nevertheless, yet, still, even so, neither … nor. Example 1.The new city hall is amazing but it’s going to cost a lot. 2. He’s quite short, whereas his sister is tall. 3. Although I studied hard, I couldn't pass my English Exam. 4. Even though the government has taken up many literacy programs, literacy levels among 12-15 year olds do not appear to be improving. 5. No doubt, the use of elcetronic equipment has increased our standard of living. On the other hand, people has become very dependent.
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https://icfp20.sigplan.org/details/icfp-2020-papers/24/Recovering-Purity-with-Comonads-and-Capabilities | ICFP 2020
Thu 20 - Fri 28 August 2020
Wed 26 Aug 2020 12:00 - 12:15 at ICFP NY 5 - New York 5 Chair(s): Richard A. Eisenberg
Wed 26 Aug 2020 23:00 - 23:15 at ICFP Asia 5 - Asia 5 Chair(s): Richard A. Eisenberg
In this paper, we take a pervasively effectful (in the style of ML) typed lambda calculus, and show how to extend it to permit capturing pure expressions with types. Our key observation is that, just as the pure simply-typed lambda calculus can be extended to support effects with a monadic type discipline, an impure typed lambda calculus can be extended to support purity with a comonadic type discipline.
We establish the correctness of our type system via a simple denotational model, which we call the capability space model. Our model formalises the intuition common to systems programmers that the ability to perform effects should be controlled via access to a permission or capability, and that a program is capability-safe if it performs no effects that it does not have a runtime capability for. We then identify the axiomatic categorical structure that the capability space model validates, and use these axioms to give a categorical semantics for our comonadic type system. We then give an equational theory (substitution and the call-by-value $\beta$ and $\eta$ laws) for the imperative lambda calculus, and show its soundness relative to this semantics.
Finally, we give a translation of the pure simply-typed lambda calculus into our comonadic imperative calculus, and show that any two terms which are $\beta\eta$-equal in the STLC are equal in the equational theory of the comonadic calculus, establishing that pure programs can be mapped in an equation-preserving way into our imperative calculus.
Wed 26 AugDisplayed time zone: Eastern Time (US & Canada) change
11:00 - 13:00 New York 5ICFP Program at ICFP NY 5 Chair(s): Richard A. Eisenberg Tweag I/OPublic livestreams: YouTube, Bilibili (China) 11:0015mTalk Denotational Recurrence Extraction for Amortized AnalysisICFP ProgramJoseph W. Cutler Wesleyan University, Dan Licata Wesleyan University, Norman Danner Wesleyan University DOI Media Attached 11:1515mTalk Separation Logic for Sequential Programs (Functional Pearl)ICFP ProgramArthur Charguéraud Inria DOI Media Attached 11:3015mTalk Strong Functional Pearl: Harper's Regular-Expression Matcher in CedilleICFP ProgramAaron Stump The University of Iowa, USA, Chris Jenkins The University of Iowa, Stephan Spahn The University of Iowa, Colin McDonald University of Notre Dame DOI Media Attached 11:4515mTalk Duplo: A Framework for OCaml Post-Link OptimisationICFP ProgramNandor Licker University of Cambridge, Timothy M. Jones University of Cambridge, UK DOI Media Attached 12:0015mTalk Recovering Purity with Comonads and CapabilitiesICFP ProgramVikraman Choudhury Indiana University & University of Cambridge, Neel Krishnaswami Computer Laboratory, University of Cambridge DOI Media Attached 12:1515mTalk A General Approach to Define Binders Using Matching LogicICFP ProgramXiaohong Chen University of Illinois at Urbana-Champaign, Grigore Roşu University of Illinois at Urbana-Champaign DOI Media Attached 12:3015mTalk Parsing with Zippers (Functional Pearl)ICFP ProgramPierce Darragh University of Utah, Michael D. Adams University of Michigan DOI Media Attached 12:4515mTalk Regular Language Type Inference with Term RewritingICFP ProgramTimothée Haudebourg Univ Rennes, Inria, CNRS, IRISA, Thomas Genet IRISA, Univ Rennes, Thomas P. Jensen INRIA Rennes DOI Media Attached
22:30 - 00:00 Asia 5ICFP Program at ICFP Asia 5 Chair(s): Richard A. Eisenberg Tweag I/OPublic livestreams: YouTube, Bilibili (China) 22:0030mTalk Denotational Recurrence Extraction for Amortized AnalysisICFP ProgramJoseph W. Cutler Wesleyan University, Dan Licata Wesleyan University, Norman Danner Wesleyan University DOI Media Attached 22:1515mTalk Separation Logic for Sequential Programs (Functional Pearl)ICFP ProgramArthur Charguéraud Inria DOI Media Attached 22:3015mTalk Strong Functional Pearl: Harper's Regular-Expression Matcher in CedilleICFP ProgramAaron Stump The University of Iowa, USA, Chris Jenkins The University of Iowa, Stephan Spahn The University of Iowa, Colin McDonald University of Notre Dame DOI Media Attached 22:4515mTalk Duplo: A Framework for OCaml Post-Link OptimisationICFP ProgramNandor Licker University of Cambridge, Timothy M. Jones University of Cambridge, UK DOI Media Attached 23:0015mTalk Recovering Purity with Comonads and CapabilitiesICFP ProgramVikraman Choudhury Indiana University & University of Cambridge, Neel Krishnaswami Computer Laboratory, University of Cambridge DOI Media Attached 23:1515mTalk A General Approach to Define Binders Using Matching LogicICFP ProgramXiaohong Chen University of Illinois at Urbana-Champaign, Grigore Roşu University of Illinois at Urbana-Champaign DOI Media Attached 23:3015mTalk Parsing with Zippers (Functional Pearl)ICFP ProgramPierce Darragh University of Utah, Michael D. Adams University of Michigan DOI Media Attached 23:4515mTalk Regular Language Type Inference with Term RewritingICFP ProgramTimothée Haudebourg Univ Rennes, Inria, CNRS, IRISA, Thomas Genet IRISA, Univ Rennes, Thomas P. Jensen INRIA Rennes DOI Media Attached | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.23394326865673065, "perplexity": 14704.998293656263}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662543797.61/warc/CC-MAIN-20220522032543-20220522062543-00404.warc.gz"} |
https://www.dspe.nl/knowledge/thermomechanics/chapter-2-in-depth/2-4-thermal-radiation/2-4-3-gebhard-method/near-black-surfaces/ | Chapter 2 - In depth
# 2.4.3.1 Near black surfaces
The Gebhart method describes the radiative heat transfer in terms of heat coming from one surface and absorbed by another, including all reflections. The Gebhart matrix traces exactly the radiative transfer contribution of each surface to the others.
For two surfaces with high emissivities (close to 1) the Gebhart factor can be simplified by:
Reflections are then not taken into account, but because of the low reflectivity its fraction is relatively small and therefore also the error you make. In that case the relation becomes:
Our sponsors | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8574055433273315, "perplexity": 1355.6764142423913}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030334596.27/warc/CC-MAIN-20220925193816-20220925223816-00649.warc.gz"} |
http://math.stackexchange.com/questions/67773/how-do-i-integrate-e-sqrtx-using-the-substitution-rule | # ¿How do I integrate $e^\sqrt{x}$, using the substitution rule?
I've been trying to integrate that function, but it looks like I'm missing something, so can any one please show me how to integrate $e^\sqrt{x}$, in order to correct my procedure. Thanks
-
If $x=u^2$, then $\mathrm dx=\dots$ – Guess who it is. Sep 26 '11 at 21:53
Hint: substitute $u = \sqrt{x}$. – Robert Israel Sep 26 '11 at 21:54
No is not a homework I'd tried to do the same substitution that is shown down in the first answer, but then I don't know what to do then, since there is a product in the integrand. – Davynch0 Sep 26 '11 at 22:13
You're going to want to start with a $u$-substitution $u=\sqrt{x}$. Notice then that $u^2=x$, so $2udu=dx$. Then $$\int e^\sqrt{x}dx=2\int e^u u\ du.$$
You can then proceed by integration by parts.
To get started, you can set $w=u$ and $dv=e^u\ du$, and use the fact that $\int w\ dv= wv-\int v\ dw$. Lastly, don't forget to substitute back to get the integral in terms of $x$.
Continuing, $dw=du$ and $v=e^u$. Then $$\int w\ dv= wv-\int v\ dw = e^u u-\int e^u\ du=e^u u-e^u.$$ So $$\int e^\sqrt{x}dx=2\int e^u u\ du=2e^uu-2e^u+C=2e^\sqrt{x}(\sqrt{x}-1)+C$$ after back substituting $u=\sqrt{x}$ and adding a possible constant term.
-
I don't know how to integrate by parts, can't it be solved by the substitution rule at all? – Davynch0 Sep 26 '11 at 22:07
@Dav Since you say it is not homework, I've tried to add a more complete solution. Hopefully it's clearer. – yunone Sep 26 '11 at 22:20
thanks a lot @yunone – Davynch0 Sep 26 '11 at 22:21
Not homework, and you don't know integration by parts? Maybe that is why it is not (yet) homework. Maybe it WILL be homework later, after you do learn integration by parts! – GEdgar Sep 27 '11 at 0:12
@Davyncho: It really is (after the natural substitution) a standard integration by parts. But if we insist on substitution alone, we can (I am joking, but it is true) use $u=(\sqrt{x}-1)e^\sqrt{x}$. – André Nicolas Sep 27 '11 at 1:37 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9552062749862671, "perplexity": 403.76888809223664}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042987127.36/warc/CC-MAIN-20150728002307-00162-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://stats.stackexchange.com/questions/396352/how-to-validate-models-beyond-checking-for-overfitting | # How to validate models beyond checking for overfitting
I have an unusual problem, which is that my model is performing too well and I am struggling to trust it.
The data is a table of "snapshots" about moments in games of chess. For example, a game that lasted 20 minutes might have 4 observations in the data, corresponding to the state of play at 1, 6, 11 and 16 minutes into the game. Features are things like how many moves my player has made, how many pawns he's lost, whether he's lost his queen and so on. The target feature on each observation is whether or not this player eventually won the game, and that's what I want to predict.
I trained a model (a RandomForestClassfier) on a bunch of data. The outcome was a 0.929 Accuracy and 0.983 AUC score; that score is so high that I struggle to trust it, so i want to validate it as securely as possible.
Strangely, the model doesn't seem to be significantly overfitted:
rfc = RandomForestClassifier(n_jobs=6, max_depth=15)
x_train, x_test, y_train, y_test = train_test_split(
df_full.drop(
'Status',
axis=1
),
df_full.Status
)
rfc.fit(x_train, y_train)
print('Train Score: ',
rfc.score(x_train, y_train),
'Test Score: ',
rfc.score(x_test, y_test),
'Test AUC Score: ',
roc_auc_score(y_test, rfc.predict_proba(x_test)[:,1])
)
Train Score: 0.9350048879188833 Test Score: 0.929179472533281 Test AUC Score: 0.9832906048250383
It's performing slightly better on the training set (750k observations) compared to the testing set (250k), but only by about 0.005 accuracy score. I've also performed cross validation using StratifiedKFold(shuffle=True, n_splits=5) and gotten similar scores. Now the character of some features in the dataset are changing over time. For example for newer observations the "GameLength" feature is trending firmly downwards and the player is getting better and better, winning more often:
So I decided to test the possibility that I'm overfitting to the earlier observations some how by splitting a random sample out of the dataframe, then scoring the model against observations from the sample with CreatedDate < 2018-01-01 and against observations from the sample with CreatedDate >= 2018-01-01. This does seem to bear out that hypothesis:
df_s = df.sample(frac=0.25)
df = df.drop(df_s.index)
df_s_1 = df_s.loc[df_s.CreatedDate < '2018-01-01']
df_s_2 = df_s.loc[df_s.CreatedDate >= '2018-01-01']
rfc = RandomForestClassifier(n_jobs=6, max_depth=15)
x_train, x_test, y_train, y_test = train_test_split(
df.drop(
'Status',
axis=1
),
df.Status
)
rfc.fit(x_train, y_train)
print('Full Train Score: ',
rfc.score(x_train, y_train),
'Full Test Score: ',
rfc.score(x_test, y_test),
'Holdout Pre 2018 Score: ',
rfc.score(df_s_1.drop('Status', axis=1), df_s_1.Status),
'Holdout Post 2018 Score: ',
rfc.score(df_s_2.drop('Status', axis=1), df_s_2.Status)
)
Full Train Score: 0.9285909152912291
Full Test Score: 0.9207593281991532
Holdout Pre 2018 Score: 0.9304484856471416
Holdout Post 2018 Score: 0.889780437600061
We can see that the Post-2018 Score is significantly lower than the Pre-2018 score. This problem is not specific to the holdout data however. If I compare the prediction accuracy against the main set, they follow broadly equivalent patterns:
Which would seem to imply the model is reasonably well fit and that it simply predicts new observations less well; presumably because they're drowned out by the much larger number of earlier observations and their different characteristics. With that being the case, I retrained the model on just those observations later than 2018-01-01 to the following results:
df3 = df.loc[df.CreatedDate >= '2018-01-01'].drop(['score', 'Correct_Prediction'], axis=1)
x3_train, x3_test, y3_train, y3_test = train_test_split(df3.drop(['CreatedDate', 'Status', 'LifeBin'], axis=1), df3.Status)
rfc3 = RandomForestClassifier(max_depth=15, n_jobs=6)
rfc3.fit(x3_train, y3_train)
print('Train Score: ',
rfc3.score(x3_train, y3_train),
'Test Score: ',
rfc3.score(x3_test, y3_test)
)
Train Score: 0.9588592284513856 Test Test Score: 0.9382511713179874
There's now much less of a trend, and the model is back to its previous good level of performance. I'm out of ideas to poke holes in that score now, so my question is is there anything else I can do to test the validity of that score?
• I think you lead me down the right path here. Your comment about the independence of the observations reminded me I should be using GroupKFold() to take the slices for cross_validation, which I wasn't doing. When I do that the score drops significantly. – Dan Scally Mar 8 '19 at 15:27 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.43774643540382385, "perplexity": 3585.0720162298426}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250613416.54/warc/CC-MAIN-20200123191130-20200123220130-00542.warc.gz"} |
https://www.zora.uzh.ch/id/eprint/48254/ | # Implications of high-resolution simulations on indirect dark matter searches
Pieri, L; Lavalle, J; Bertone, G; Branchini, E (2011). Implications of high-resolution simulations on indirect dark matter searches. Physical Review D, 83(2):023518.
## Abstract
We study the prospects for detecting the annihilation products of dark matter (DM) in the framework of the two highest-resolution numerical simulations currently available, i.e., Via Lactea II and Aquarius. We propose a strategy to determine the shape and size of the region around the Galactic center that maximizes the probability of observing a DM signal, and we show that, although the predicted flux can differ by a factor of 10 for a given DM candidate in the two simulation setups, the search strategy remains actually unchanged, since it relies on the angular profile of the annihilation flux, not on its normalization. We present mock γ-ray maps that keep into account the diffuse emissions produced by unresolved halos in the Galaxy, and we show that, in an optimistic DM scenario, a few individual clumps can be resolved above the background with the Fermi-LAT. Finally, we calculate the energy-dependent boost factors for positrons and antiprotons and show that they are always of O(1), and, therefore, they cannot lead to the large enhancements of the antimatter fluxes required to explain the recent PAMELA, ATIC, Fermi, and HESS data. Still, we show that the annihilation of 100 GeV weakly interacting massive particles into charged lepton pairs may contribute significantly to the positron budget.
## Abstract
We study the prospects for detecting the annihilation products of dark matter (DM) in the framework of the two highest-resolution numerical simulations currently available, i.e., Via Lactea II and Aquarius. We propose a strategy to determine the shape and size of the region around the Galactic center that maximizes the probability of observing a DM signal, and we show that, although the predicted flux can differ by a factor of 10 for a given DM candidate in the two simulation setups, the search strategy remains actually unchanged, since it relies on the angular profile of the annihilation flux, not on its normalization. We present mock γ-ray maps that keep into account the diffuse emissions produced by unresolved halos in the Galaxy, and we show that, in an optimistic DM scenario, a few individual clumps can be resolved above the background with the Fermi-LAT. Finally, we calculate the energy-dependent boost factors for positrons and antiprotons and show that they are always of O(1), and, therefore, they cannot lead to the large enhancements of the antimatter fluxes required to explain the recent PAMELA, ATIC, Fermi, and HESS data. Still, we show that the annihilation of 100 GeV weakly interacting massive particles into charged lepton pairs may contribute significantly to the positron budget.
## Statistics
### Citations
Dimensions.ai Metrics
115 citations in Web of Science®
123 citations in Scopus®
### Altmetrics
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http://mathhelpforum.com/calculus/70250-volumes-solids-revolutions.html | # Math Help - Volumes of solids of revolutions
1. ## Volumes of solids of revolutions
Find the volume of the solid obtained by rotating the region bounded by the graphs of y=x^(2) and x=y^(2) around the line x=-1.
Thanks for the help.
2. using cylindrical shells w/r to x ...
$V = 2\pi \int_0^1 (x+1)(\sqrt{x} - x^2) \, dx
$
using washers w/r to y ...
$V = \pi \int_0^1 (\sqrt{y} + 1)^2 - (y^2 + 1)^2 \, dy$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7161146998405457, "perplexity": 1282.8659943335683}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-27/segments/1435375093974.67/warc/CC-MAIN-20150627031813-00035-ip-10-179-60-89.ec2.internal.warc.gz"} |
http://www.math.colostate.edu/graduate.shtml | Education is not the filling of a pail, it is the lighting of a fire. - W. B. Yeats
### NEWS in the Department of Mathematics Graduate Announcements
Eric Hanson - PhD defense
Date: Tuesday, June 23, 2015
Time: 10:00 a.m.
Place: Weber 201
Title: Algorithms in Numerical Algebraic Geometry and Applications
Committee:
Dr. Chris Peterson
Dr. Renzo Cavalieri
Dr. Anthony Maciejewski
Abstract: The topics in this talk, while independent, are unified under the field of numerical algebraic geometry. With ties to some of the oldest areas in mathematics, numerical algebraic geometry is relatively young as a field of study in its own right. The field is concerned with the numerical approximation of the solution sets to systems of polynomial equations and the manipulation of the these sets. Given a system of polynomial equations, the methods of numerical algebraic geometry produce numerical approximations of the isolated solutions, as well as points on any positive-dimensional components of the solution set. In a short time, the work done in numerical algebraic geometry has significantly pushed the boundary of what is computable. This talk will provide an introduction to numerical algebraic geometry and then discuss three algorithms/applications: perturbed homotopies, exceptional sets and fiber products, and a numerical approach to finding unit distance embeddings of finite simple graphs. A short description of each topic appears below:
One of the most recent advances in numerical algebraic geometry is regeneration, an equation-by-equation homotopy method that is often more efficient then other approaches. However, the basic form of regeneration will not necessarily find all isolated singular solutions of a polynomial system without the additional cost of using deflation. We present an alternative to deflation in the form of perturbed homotopies for solving polynomial systems. In particular, we propose first solving a perturbed version of the polynomial system, followed by a parameter homotopy to remove the perturbation. The aim of this is two-fold. First, such perturbed homotopies are sometimes more efficient than regular homotopies, though they can also be less efficient. Second, a useful consequence is that the application of this perturbation to regeneration will yield all isolated solutions, including all singular isolated solutions. This version of regeneration -- {\em perturbed regeneration} -- can decrease the efficiency of regeneration but increases its applicability.
The second topic of this talk considers families of polynomial systems which depend on parameters. There is a typical dimension for the variety defined by a system in the family; however, this dimension may jump for parameters in algebraic subsets of the parameter space. Sommese and Wampler exploited fiber products to give a numerical method for identifying these special parameter values. We propose a refined numerical approach to fiber products, which uses recent advancements in numerical algebraic geometry, such as regeneration extension. We show that this method is sometimes more efficient then known techniques. In part, this gain in efficiency is due to the fact that regeneration extension allows the construction of the fiber product to be restricted to specified irreducible components. This work is motivated by applications in Kinematics - the study of mechanisms. As such we use an algebraic model of a two link arm to illustrate the algorithms we develop.
The final topic is the identification of unit distance embeddings of finite simple graphs. Given a graph $G(V,E)$, a unit distance embedding is a map $\phi$ from the vertex set $V$ into a metric space $M$ such that if $\{v_i,v_j\}\in E$ then the distance between $\phi(v_i)$ and $\phi(v_j)$ in $M$ is one. Given $G$ we cast the question of the existence of a unit distance embedding in $\mathbb{R}^n$ as the question of the existence of a real solution to a system of polynomial equations. As a consequence, we are able to develop theoretic algorithms for determining the existence of a unit distance embedding and for determining the smallest dimension of $\mathbb{R}^n$ for which a unit distance embedding of $G$ exists (that is, we determine the minimal embedding dimension of $G$). We put these algorithms into practice using the methods of numerical algebraic geometry. In particular, we consider unit distance embeddings of the Heawood Graph. This is the smallest example of a point-line incidence graph of a finite projective plan. In 1972, Chv\'{a}tal conjectured that point-line incidence graphs of finite projective planes do not have unit-distance embeddings into $\mathbb{R}^2$. In other words, Chv\'{a}tal conjectured that the minimal embedding dimension of any point-line incidence graph of a finite projective plane is at least $3$. We disprove this conjecture, adding hundreds of counterexamples to the $11$ known counterexamples found by Gerbracht.
Steve Ihde - PhD defense
Date: Wednesday, June 24, 2015
Time: 2:00 p.m.
Place: Weber 201
Title: Preconditioning Polynomial Systems Using Macaulay Dual Spaces
Committee
Dr. Chris Peterson
Dr. Alexander Hulpke
Dr. Peter Young
Abstract:
Numerical Algebraic Geometry is concerned with using numerical methods to solve polynomial systems. The main tool from this area is the method of Homotopy Continuation. Sometimes, this method is not efficient due to a number of factors. This project concerns the preconditioning of polynomial systems in order to be better suited for homotopy continuation.
In 2010, Hauenstein showed that computations could be done on the basis of a polynomial ideal by working in the Macaulay dual space. We will show that these computations can be used to find an H-basis, first introduced in 1916 by Macaulay. This H-basis will create a preconditioned set of homogeneous polynomials from a zero-dimensional system. We then improve upon these methods using the Closedness Subspace, first introduced by Zeng in 2009.
Background on homotopy continuation, h-bases, and the closedness subspace will be presented. This will lead to algorithms and examples of preconditioning for homotopy continuation.
Sofya Chepushtanova - PhD defense
Date: Thursday, June 25, 2015
Place: Weber, 201
Time: 10:00 a.m.
Title: Algorithms for Feature Selection and Pattern Recognition on Grassmann Manifolds
Committee:
Dr. Chris Peterson
Dr. Dan Bates
Dr. Asa Ben-Hur
Abstact: Three distinct application-driven research projects, inspired by ideas and topics from geometric data analysis, machine learning, and computational topology, are presented. We first consider feature selection based on sparse support vector machines (SSVMs) applied to hyperspectral band selection problem. A supervised embedded approach is proposed using the property of SSVMs to exhibit a model structure that includes a clearly identifiable gap between zero and non-zero feature vector weights that permits important spectral bands to be definitively selected in conjunction with the classification problem. Second, we describe an approach for performing set-to-set pattern recognition, via classification of data on embedded Grassmannians. A set of points from a given class characterizes the variability of the class information, so we propose organizing sets of data as subspaces on a Grassmann manifold. Multidimensional scaling finds Euclidean embeddings of the manifold, preserving or approximating the Grassmannian geometry based on a chosen distance measure. SSVMs are trained in the Euclidean space for classification and identification of optimal dimensions of embedded subspaces. Lastly, we consider an application of persistent homology to hyperspectral data analysis on the Grassmann manifolds. Persistent homology (PH) is a method of topological data analysis (TDA) that can be applied to a data set to capture the persistence of topological structure. Using the Grassmannian framework affords a form of data compression while retaining pertinent data structure. In this setting it becomes feasible to analyze large volumes of hyperspectral data as the high computational cost of PH applied to the original data space is greatly reduced.
Mike Mikucki - PhD Defense
Date: Friday, June 26, 2015
Time: 1:00 p.m.
Place: Weber 201
Title: Electromechanical and curvature driven molecular flows for lipid membranes | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8581714630126953, "perplexity": 777.1517836601398}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-27/segments/1435375097475.46/warc/CC-MAIN-20150627031817-00208-ip-10-179-60-89.ec2.internal.warc.gz"} |
http://scholarship.rice.edu/handle/1911/19319?show=full | # Hydrodynamic and molecular dependence of neutrophil-neutrophil adhesion
### Files in this item
Files Size Format View
9827452.PDF 5.481Mb application/pdf
dc.creator Taylor, Andrew David 2007-08-21T01:55:41Z 2007-08-21T01:55:41Z 1998 http://hdl.handle.net/1911/19319 Homotypic adhesion of neutrophils stimulated with chemoattractant is analogous to capture on vascular endothelium in that both processes depend on L-selectin and $\beta\sb2$-integrin adhesion receptors. Under hydrodynamic shear, cell adhesion requires that receptors bind sufficient ligand over the duration of intercellular contact to withstand hydrodynamic stresses. A detailed examination of the effect of shear rate and shear stress on neutrophil-neutrophil adhesion was performed using cone plate viscometry. A collisional analysis based on Smoluchowski's theory was employed to fit the kinetics of aggregation with an adhesion efficiency. Adhesion efficiency increased with shear rate from $\sim$20% at 100 s$\sp{-1}$ to $\sim$80% at 400 s$\sp{-1}.$ The increase in adhesion efficiency with shear was dependent on L-selectin and peak efficiency was maintained over a relatively narrow range of shear rates (400-800 s$\sp{-1})$ and shear stresses (4-7 dyn/cm$\sp2).$ When L-selectin was blocked with antibody, $\beta\sb2$-integrin supported adhesion at low shear rates which decreased with increasing shear $\ge$100 s$\sp{-1}.$ At low shear, neutrophil-neutrophil adhesion was dependent on LFA-1 (CD11a/CD18) binding to ICAM-3 (CD50) and Mac-1 (CD11b/CD18) binding an unknown ligand. Adhesion became more dependent on Mac-1 with time after chemotactic stimulation and as shear rate was increased. The binding kinetics of selectin and integrin appear to be optimized to function within discrete ranges of shear rate and stress, providing an intrinsic mechanism for the transition from neutrophil tethering to stable adhesion. application/pdf eng Biology, CellEngineering, BiomedicalEngineering, Chemical Hydrodynamic and molecular dependence of neutrophil-neutrophil adhesion Thesis Text Biology Rice University Doctoral Taylor, Andrew David. (1998) "Hydrodynamic and molecular dependence of neutrophil-neutrophil adhesion." Doctoral Thesis, Rice University. http://hdl.handle.net/1911/19319. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7210273146629333, "perplexity": 17290.68945689892}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-15/segments/1397609523265.25/warc/CC-MAIN-20140416005203-00658-ip-10-147-4-33.ec2.internal.warc.gz"} |
https://www.mail-archive.com/[email protected]&q=subject:%22%5C%5BNTG%5C-context%5C%5D+Hyphentation%5C%2FLinebreak+after+x+characters+inside+%5C%5CWORD%5C%3F%22&o=newest | ### Re: [NTG-context] Hyphentation/Linebreak after x characters inside \WORD?
On 4/23/2020 15:01, Benjamin Buchmuller wrote: Sorry, I have just realized that the problem might not be \WORD{} actually, so this one hyphenates: \define[2]\mycommand{ \startxrow \startxcell o#1 \stopxcell \startxcell \tt\WORD #2 \stopxcell \stopxrow }
### Re: [NTG-context] Hyphentation/Linebreak after x characters inside \WORD?
Sorry, I have just realized that the problem might not be \WORD{} actually, so this one hyphenates: \define[2]\mycommand{ \startxrow \startxcell o#1 \stopxcell \startxcell \tt\WORD #2 \stopxcell \stopxrow } Whereas these ones don’t:
### [NTG-context] Hyphentation/Linebreak after x characters inside \WORD?
Hi again, I am reading a CSV file into ConTeXt which contains long DNA sequences (>> 40 characters) to place in xtables. So far, this works fine. However, I need to uppercase the entries and need to \tt them. When I do this inside \WORD however, they don’t hyphenate any more. I’m using: | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9293782711029053, "perplexity": 17937.9514643415}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178364932.30/warc/CC-MAIN-20210302221633-20210303011633-00056.warc.gz"} |
https://vulners.com/openvas/OPENVAS:855618 | # Solaris Update for cu 111072-01
2009-06-03T00:00:00
ID OPENVAS:855618
Type openvas
Reporter Copyright (C) 2009 Greenbone Networks GmbH
Modified 2017-02-20T00:00:00
## Check for the Version of cu
``` ```
###############################################################################
# OpenVAS Vulnerability Test
#
# Solaris Update for cu 111072-01
#
# Authors:
# System Generated Check
#
# Copyright (c) 2009 Greenbone Networks GmbH, http://www.greenbone.net
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2
# (or any later version), as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
###############################################################################
tag_affected = "cu on solaris_5.8_x86";
tag_insight = "The remote host is missing a patch containing a security fix,
which affects the following component(s):
cu
tag_solution = "Please Install the Updated Packages.";
if(description)
{
script_id(855618);
script_version("\$Revision: 5359 \$");
script_tag(name:"last_modification", value:"\$Date: 2017-02-20 12:20:19 +0100 (Mon, 20 Feb 2017) \$");
script_tag(name:"creation_date", value:"2009-06-03 12:19:17 +0200 (Wed, 03 Jun 2009)");
script_tag(name:"cvss_base", value:"4.4");
script_tag(name:"cvss_base_vector", value:"AV:L/AC:M/Au:N/C:P/I:P/A:P");
script_xref(name: "SUNSolve", value: "111072-01");
script_name( "Solaris Update for cu 111072-01");
script_xref(name : "URL" , value : "http://sunsolve.sun.com/search/document.do?assetkey=1-21-111072-01-1");
script_summary("Check for the Version of cu");
script_category(ACT_GATHER_INFO);
script_family("Solaris Local Security Checks");
script_dependencies("gather-package-list.nasl");
script_tag(name : "affected" , value : tag_affected);
script_tag(name : "insight" , value : tag_insight);
script_tag(name : "solution" , value : tag_solution);
script_tag(name:"qod_type", value:"package");
script_tag(name:"solution_type", value:"VendorFix");
exit(0);
}
include("solaris.inc"); | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8173284530639648, "perplexity": 16502.664711828194}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267867055.95/warc/CC-MAIN-20180624195735-20180624215735-00505.warc.gz"} |
https://www.physicsforums.com/threads/dark-energy-is-space.34743/ | # Dark energy is space
1. Jul 12, 2004
### kurious
If I double the size of a classical,non-quantum mechanical vacuum,
I double the volume of space and its density stays constant at zero
kg/ m ^3.As the amount of dark energy in the universe increases the volume of space increases and the density stays constant.Is dark energy space?
2. Jul 16, 2004
### force5
Hi kurious;
I don't think all space is dark energy. But, I think all dark energy is space.
Just my thoughts.
Similar Discussions: Dark energy is space | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9774526357650757, "perplexity": 2703.4215796585113}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917121216.64/warc/CC-MAIN-20170423031201-00484-ip-10-145-167-34.ec2.internal.warc.gz"} |
https://www.nag.com/numeric/nl/nagdoc_latest/clhtml/e04/e04rec.html | # NAG CL Interfacee04rec (handle_set_linobj)
Settings help
CL Name Style:
## 1Purpose
e04rec is a part of the NAG optimization modelling suite and defines or redefines the objective function of the problem to be linear.
## 2Specification
#include
void e04rec (void *handle, Integer nvar, const double cvec[], NagError *fail)
The function may be called by the names: e04rec or nag_opt_handle_set_linobj.
## 3Description
After the handle has been initialized (e.g., e04rac has been called), e04rec may be used to define the objective function of the problem as a linear function ${c}^{\mathrm{T}}x$ using a dense vector $c$. If the objective function has already been defined, it will be overwritten. If $c=0$, any existing objective function is removed, no new one is added and the problem will be solved as a feasible point problem. It is recommended to use e04rfc if the vector $c$ is sparse. e04tec may be used to set individual elements ${c}_{i}$ of the linear objective.
This will typically be used for Linear Programming (LP)
$minimize x∈ℝn cTx (a) subject to lB≤Bx≤uB, (b) lx≤x≤ux , (c)$ (1)
Second-order Cone Programming (SOCP)
$minimize x∈ℝn cTx (a) subject to lB≤Bx≤uB, (b) lx≤x≤ux , (c) xGi∈Kmi,i=1,…,r, (d)$ (2)
linear Semidefinite Programming problems (SDP)
$minimize x∈ℝn cTx (a) subject to ∑ i=1 n xi Aik - A0k ⪰ 0 , k=1,…,mA , (b) lB≤Bx≤uB , (c) lx≤x≤ux , (d)$ (3)
or SDP with bilinear matrix inequalities (BMI-SDP) where the objective function has only linear terms. See Section 4.1 in the E04 Chapter Introduction for more details about the NAG optimization modelling suite.
None.
## 5Arguments
1: $\mathbf{handle}$void * Input
On entry: the handle to the problem. It needs to be initialized (e.g., by e04rac) and must not be changed between calls to the NAG optimization modelling suite.
2: $\mathbf{nvar}$Integer Input
On entry: $n$, the current number of decision variables $x$ in the model.
3: $\mathbf{cvec}\left[{\mathbf{nvar}}\right]$const double Input
On entry: the dense vector $c$ of the objective function.
4: $\mathbf{fail}$NagError * Input/Output
The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).
## 6Error Indicators and Warnings
NE_ALLOC_FAIL
Dynamic memory allocation failed.
See Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
On entry, argument $⟨\mathit{\text{value}}⟩$ had an illegal value.
NE_HANDLE
The supplied handle does not define a valid handle to the data structure for the NAG optimization modelling suite. It has not been properly initialized or it has been corrupted.
NE_INTERNAL_ERROR
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.
See Section 7.5 in the Introduction to the NAG Library CL Interface for further information.
NE_NO_LICENCE
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library CL Interface for further information.
NE_PHASE
The problem cannot be modified right now, the solver is running.
NE_REF_MATCH
On entry, ${\mathbf{nvar}}=⟨\mathit{\text{value}}⟩$, expected $\mathrm{value}=⟨\mathit{\text{value}}⟩$.
Constraint: nvar must match the current number of variables of the model in the handle.
Not applicable.
## 8Parallelism and Performance
e04rec is not threaded in any implementation. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 18, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.71497642993927, "perplexity": 1893.5063073395359}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178365454.63/warc/CC-MAIN-20210303042832-20210303072832-00606.warc.gz"} |
http://rasmodel.org/components/ras/ras_gaps.html | # Ras regulation by RasGAPs¶
GTP hydrolysis by Ras is slow but is accelerated by RasGAPs.
[PMID9247124]: The GTP-binding proteins return to the inactive state by virtue of the GTPase reaction, which is usually very slow but can be accelerated by the action of GAPs, in the case of the Ras/Ras-GAPs and Ran/Ran-GAP interactions by several orders of magnitude [PMID1569940] [PMID8262937] [PMID7548002].
## RasGAPs for the Ras subfamily¶
There are several GAPs for the Ras subfamily.
[PMID9247124]: Five mammalian GAPs for Ras have been described. The first, p120GAP, is the prototype of this class of proteins and was the first one to be isolated (20, 21 and 22). Apart from being a regulator of Ras, its N-terminal domain contains a number of signalling modules such as SH2, SH3, PH, Calb domains and is believed to be a signal transduction molecule that may act independently of Ras (23 and 24).
### RASA1¶
The domain information for RASA1 was taken from Uniprot (ID: P20936).
def rasgap_monomers():
# p120GAP = RASA1.
# CaLB (calcium lipid binding domain) is also known as a C2 domain.
Monomer('RASA1', ['SH2_1', 'SH3', 'SH2_2', 'PH', 'C2', 'rasgap'])
### NF1¶
[PMID9247124]: The second Ras-specific GAP is neurofibromin (NF1), which is the product of the neurofibromatosis gene [PMID25] and has also been shown to stimulate the GTPase of Ras 26, 27 and 28. This gene has been found to be frequently mutated in patients with the disease neurofibromatosis type I 29, 30 and 31 but also, albeit less frequently, in solid tumors [PMID32].
Monomer('NF1', ['rasgap', 'CRALTRIO'])
### RASA2¶
[PMID9247124]: GAP1m, a mammalian homologue of the Drosophila GAP1 gene [PMID33], has been described, and a close homologue GAPIII [PMID34], both of which contain, in addition to the GRD (GAP-related domain), C2 domains and a PH domain.
# GAP1m = RASA2
Monomer('RASA2', ['C2_1', 'C2_2', 'rasgap', 'PH', 'BTK'])
### RASA3¶
NOTE: As it turned out GAPIII and GAP1IP4BP are the same protein.
[PMID9247124]: Recently an inositol-4-phosphate (IP4) binding protein GAP1IP4BP has been purified, cloned, and found to contain a Ras-GAP catalytic domain. In contrast to the other GAP mentioned, which are specific for Ras, GAP1IP4BP stimulates the GTPase of both Ras and Rap [PMID35].
# GAPIII = GAP1IP4BP = RASA3
Monomer('RASA3', ['C2_1', 'C2_2', 'rasgap', 'PH', 'BTK'])
## Mechanism of accelerating hydrolysis¶
[9247124]_: Under saturating conditions of pl20GAP, the $$k_{cat}$$ of the GTPase reaction of Ras is 19 $$s^{-1}$$, which means that the reaction is stimulated more than $$10^5$$-fold, with a KD of 9.7 uM for the GAP/Ras-GTP interaction [1569940]_.
Because the co-crystal structure of Ras with RasGAP shows the occlusion of the GTP binding pocket by RasGAP, we model this by asserting that the RasGAP binds at the Switch 1/Switch 2 region on Ras. This has the effect of preventing the binding of downstream effectors such as Raf.
Further, for the time being we assume that RasGAPs bind only to the GTP-bound state, in which s1s2 are ‘closed’, i.e., once the nucleotide is in the tightly bound state; and that a RasGAP and a RasGEF cannot simultaneously be bound to the same Ras molecule.
These assumptions yield the following mechanism:
def rasgap_mediated_hydrolysis(model, ras, rasgap, kf, kr, kcat):
GTP = model.monomers['GTP']
GDP = model.monomers['GDP']
Pi = model.monomers['Pi']
# RasGAP, with an unbound RasGAP domain, binds to GTP-bound Ras with
# its Switch 1/Switch 2 region in the 'closed' state, with no RasGEF
# bound:
ras_gtp = ras(s1s2='closed', gef=None, gtp=2) % GTP(p=2)
ras_gdp = ras(s1s2='closed', gef=None, gtp=2) % GDP(p=2)
bind(rasgap, 'rasgap', ras_gtp, 'gap', [kf, kr])
# Because a GDP is being created on the right-hand side of this rule,
# it must be fully specified. This means that we need to handle
# the case when the GTP/GDP is either labeled or unlabeled.
for label in ['y', 'n']:
_macro_rule('catalyze',
rasgap(rasgap=1) % ras_gtp(gap=1, label=label) >>
rasgap(rasgap=None) +
ras_gdp(gap=None, label=label) + Pi(),
[kcat], ['kcat'])
For the time being, we include only the hydrolysis reaction for KRAS, mediated by RASA1 (P120GAP):
def kras_rasgaps(model):
KRAS = model.monomers['KRAS']
RASA1 = model.monomers['RASA1']
# Diffusion-limited KRAS/RasGAP association:
kf = 1e-2
# Calculate dissociation rate based on roughly 10 uM KD reported above
kr = 100. # KD = 100 / 0.01 = 10,000 nM = 10 uM
hydrolysis_rates = {'WT': 4300e-5,
'G12A': 32e-5,
'G12C': 20e-5,
'G12D': 89e-5,
'G12R': 20e-5,
'G12V': 24e-5,
'G13D': 20e-5,
'Q61L': 12e-5,
'Q61H': 5e-5}
# Iterate over all of the mutants that we're considering
for mutant in KRAS.site_states['mutant']:
kras = KRAS(mutant=mutant)
if mutant in hydrolysis_rates:
mutant_kcat = hydrolysis_rates[mutant]
else:
mutant_kcat = hydrolysis_rates['WT']
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http://www.jora.jp/biodz/member.html | ̃z[y[W͊]҂̂݃NĂ܂B
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| ̃y[W̃gbv | | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9981544017791748, "perplexity": 28.26564531334152}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818696677.93/warc/CC-MAIN-20170926175208-20170926195208-00215.warc.gz"} |
https://socialsci.libretexts.org/Bookshelves/Economics/Book%3A_Macroeconomics_(OpenStax)/04%3A_Labor_and_Financial_Markets/0Introduction_to_Labor_and_Financial_Markets | According to the Bureau of Labor Statistics, registered nursing jobs are expected to increase by 19% between 2012 and 2022. The median annual wage of $67,930 (in 2012) is also expected to increase. The BLS forecasts that 526,000 new nurses will be needed by 2022. One concern is the low rate of enrollment in nursing programs to help meet the growing demand. According to the American Association of Colleges of Nursing (AACN), enrollment in 2011 increased by only 5.1% due to a shortage of nursing educators and teaching facilities. These data tell us, as economists, that the market for healthcare professionals, and nurses in particular, will face several challenges. Our study of supply and demand will help us to analyze what might happen in the labor market for nursing and other healthcare professionals, as discussed in the second half of this case at the end of the chapter. Note: Introduction to Labor and Financial Market In this chapter, you will learn about: • Demand and Supply at Work in Labor Markets • Demand and Supply in Financial Markets • The Market System as an Efficient Mechanism for Information The theories of supply and demand do not apply just to markets for goods. They apply to any market, even markets for labor and financial services. Labor markets are markets for employees or jobs. Financial services markets are markets for saving or borrowing. When we think about demand and supply curves in goods and services markets, it is easy to picture who the demanders and suppliers are: businesses produce the products and households buy them. Who are the demanders and suppliers in labor and financial service markets? In labor markets job seekers (individuals) are the suppliers of labor, while firms and other employers who hire labor are the demanders for labor. In financial markets, any individual or firm who saves contributes to the supply of money, and any who borrows (person, firm, or government) contributes to the demand for money. As a college student, you most likely participate in both labor and financial markets. Employment is a fact of life for most college students: In 2011, says the BLS, 52% of undergraduates worked part time and another 20% worked full time. Most college students are also heavily involved in financial markets, primarily as borrowers. Among full-time students, about half take out a loan to help finance their education each year, and those loans average about$6,000 per year. Many students also borrow for other expenses, like purchasing a car. As this chapter will illustrate, we can analyze labor markets and financial markets with the same tools we use to analyze demand and supply in the goods markets. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.21368326246738434, "perplexity": 1475.1408528909892}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-09/segments/1550247518497.90/warc/CC-MAIN-20190222155556-20190222181556-00066.warc.gz"} |
http://www.ni.com/documentation/en/vision-development-module/19.0/ni-vision-algorithms-node-ref/convert-roi-to-rectangle/ | # Convert from ROI (Convert ROI to Rectangle) (G Dataflow)
Converts an ROI descriptor to a rectangle or rotated rectangle.
The contour of the ROI Descriptor is always of the type rotated rectangle.
## ROI descriptor
Descriptor that defines the rectangle.
### global rectangle
Minimum rectangle required to contain all of the contours in the ROI.
### Contours
Individual shapes that define an ROI.
#### ID
Object specifying if contour is the external or internal edge of an ROI.
#### Type
Shape type of the contour.
#### Coordinates
Relative position of the contour.
## error in
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Standard Error Behavior
Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.
error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.
If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.
If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.
Default: No error
## rectangle
Rectangular region.
The left, top, right, and bottom coordinates describe a non-rotated rectangle. The rotation parameter specifies the rotation angle of the rectangle around its center.
### left
X-coordinate of the upper left corner of the rectangle.
### top
Y-coordinate of the upper left corner of the rectangle.
### right
X-coordinate of the bottom right corner of the rectangle.
### bottom
Y-coordinate of the bottom right corner of the rectangle.
### rotation
Rotation angle in degrees of the rectangle with its center as point of rotation.
If the rotation angle does not equal zero, the left, top, right, and bottom coordinates are not the actual coordinates of the upper left and bottom right corner of the rectangle, but their position if the rotation angle equals zero.
## error out
Error information.
The node produces this output according to standard error behavior.
Standard Error Behavior
Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.
error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.
If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.
If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported
Web Server: Not supported in VIs that run in a web application | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8140066862106323, "perplexity": 2176.8621321337714}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496670987.78/warc/CC-MAIN-20191121204227-20191121232227-00085.warc.gz"} |
http://www.ck12.org/geometry/Midsegment-Theorem/lesson/Midsegment-Theorem/r11/ | <meta http-equiv="refresh" content="1; url=/nojavascript/">
You are viewing an older version of this Concept. Go to the latest version.
# Midsegment Theorem
## Midsegment of a triangle joins the midpoints of two sides and is half the length of the side it is parallel to.
%
Progress
Practice Midsegment Theorem
Progress
%
Midsegment Theorem
What if you were given $\triangle FGH$ and told that $\overline{JK}$ was its midsegment? How could you find the length of $JK$ given the length of the triangle's third side, $FH$ ? After completing this Concept, you'll be able to use the Midsegment Theorem to solve problems like this one.
### Watch This
First watch this video.
Now watch this video.
### Guidance
A line segment that connects two midpoints of the sides of a triangle is called a midsegment . $\overline{DF}$ is the midsegment between $\overline{AB}$ and $\overline{BC}$ .
The tic marks show that $D$ and $F$ are midpoints. $\overline{AD} \cong \overline{DB}$ and $\overline{BF} \cong \overline{FC}$ . For every triangle there are three midsegments.
There are two important properties of midsegments that combine to make the Midsegment Theorem . The Midsegment Theorem states that the midsegment connecting the midpoints of two sides of a triangle is parallel to the third side of the triangle, and the length of this midsegment is half the length of the third side. So, if $\overline{DF}$ is a midsegment of $\triangle ABC$ , then $DF = \frac{1}{2} AC = AE = EC$ and $\overline{DF} \| \overline{AC}$ .
Note that there are two important ideas here. One is that the midsegment is parallel to a side of the triangle. The other is that the midsegment is always half the length of this side. To play with the properties of midsegments, go to http://www.mathopenref.com/trianglemidsegment.html .
#### Example A
The vertices of $\triangle LMN$ are $L(4, 5), \ M(-2, -7)$ and $N(-8, 3)$ . Find the midpoints of all three sides, label them $O, \ P$ and $Q.$ Then, graph the triangle, plot the midpoints and draw the midsegments.
To solve this problem, use the midpoint formula 3 times to find all the midpoints. Recall that the midpoint formula is $\left ( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right )$ .
$L$ and $M = \left ( \frac{4 + (-2)}{2}, \frac{5 + (-7)}{2} \right ) = (1, -1)$ point $O$
$M$ and $N = \left ( \frac{-2 + (-8)}{2}, \frac{-7 + 3}{2} \right ) = (-5, -2)$ , point $P$
$L$ and $N = \left ( \frac{4 + (-8)}{2}, \frac{5 + 3}{2} \right ) = (-2, 4)$ , point $Q$
The graph is to the right.
#### Example B
Mark all the congruent segments on $\triangle ABC$ with midpoints $D, \ E$ , and $F$ .
Drawing in all three midsegments, we have:
Also, this means the four smaller triangles are congruent by SSS.
Now, mark all the parallel lines on $\triangle ABC$ , with midpoints $D, \ E$ , and $F$ .
#### Example C
$M, \ N$ , and $O$ are the midpoints of the sides of $\triangle XYZ$ .
Find
a) $MN$
b) $XY$
c) The perimeter of $\triangle XYZ$
To solve, use the Midsegment Theorem.
a) $MN = OZ = 5$
b) $XY = 2(ON) = 2 \cdot 4 = 8$
c) Add up the three sides of $\triangle XYZ$ to find the perimeter.
$XY + YZ + XZ = 2 \cdot 4 + 2 \cdot 3 + 2 \cdot 5 = 8 + 6 + 10 = 24$
Remember: No line segment over $MN$ means length or distance.
### Guided Practice
1. Find the value of $x$ and $AB$ . $A$ and $B$ are midpoints.
2. True or false: If a line passes through two sides of a triangle and is parallel to the third side, then it is a midsegment.
3. Find $y$ . You may assume that the line segment within the triangle is a midsegment.
Answers:
1. $AB = 34 \div 2 = 17$ . To find $x$ , set $3x - 1$ equal to 17.
$3x - 1 & = 17\\3x & = 18\\x & =6$
2. This statement is false. A line that passes through two sides of a triangle is only a midsegment if it passes through the midpoints of the two sides of the triangle.
3. Because a midsegment is always half the length of the side it is parallel to, we know that $y=\frac{1}{2}(36)=18$ .
### Practice
Determine whether each statement is true or false.
1. The endpoints of a midsegment are midpoints.
2. A midsegment is parallel to the side of the triangle that it does not intersect.
3. There are three congruent triangles formed by the midsegments and sides of a triangle.
4. There are three midsegments in every triangle.
$R, \ S, \ T$ , and $U$ are midpoints of the sides of $\triangle XPO$ and $\triangle YPO$ .
1. If $OP = 12$ , find $RS$ and $TU$ .
2. If $RS = 8$ , find $TU$ .
3. If $RS = 2x$ , and $OP = 20$ , find $x$ and $TU$ .
4. If $OP = 4x$ and $RS = 6x - 8$ , find $x$ .
For questions 9-15, find the indicated variable(s). You may assume that all line segments within a triangle are midsegments.
1. The sides of $\triangle XYZ$ are 26, 38, and 42. $\triangle ABC$ is formed by joining the midpoints of $\triangle XYZ$ .
1. What are the lengths of the sides of $\triangle ABC$ ?
2. Find the perimeter of $\triangle ABC$ .
3. Find the perimeter of $\triangle XYZ$ .
4. What is the relationship between the perimeter of a triangle and the perimeter of the triangle formed by connecting its midpoints?
Coordinate Geometry Given the vertices of $\triangle ABC$ below find the midpoints of each side.
1. $A(5, -2), \ B(9, 4)$ and $C(-3, 8)$
2. $A(-10, 1), \ B(4, 11)$ and $C(0, -7)$
3. $A(-1, 3), \ B(5, 7)$ and $C(9, -5)$
4. $A(-4, -15), \ B(2, -1)$ and $C(-20, 11)$
### Vocabulary Language: English Spanish
midsegment
midsegment
A midsegment connects the midpoints of two sides of a triangle or the non-parallel sides of a trapezoid.
Congruent
Congruent
Congruent figures are identical in size, shape and measure.
Midpoint Formula
Midpoint Formula
The midpoint formula says that for endpoints $(x_1, y_1)$ and $(x_2, y_2)$, the midpoint is $@\left( \frac{x_1+x_2}{2}, \frac{y_1+y_2}{2} \right)@$.
### Explore More
Sign in to explore more, including practice questions and solutions for Midsegment Theorem.
Please wait...
Please wait... | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 91, "texerror": 0, "math_score": 0.728731632232666, "perplexity": 357.25740699903645}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1433195035877.3/warc/CC-MAIN-20150601214355-00075-ip-10-180-206-219.ec2.internal.warc.gz"} |
http://gafferongames.com/virtualgo/collision-response-and-coulomb-friction/ | # Collision Response And Coulomb Friction
February 9, 2013
Hello, I’m Glenn Fiedler and welcome to Virtual Go, my project to simulate a Go board and stones.
In previous articles we mathematically defined the go stone, rendered it, determined how it moves and rotates, accelerated it by gravity and detected when it collides with the go board. We also discussed the inertia tensor and how it affects the movement of the go stone.
In this article we reach our first milestone: a go stone bouncing and coming to rest on the go board.
We do this using a technique called impulse-based collision response.
The concept is simple: apply an impulse at the point of collision to make the go stone bounce.
Exactly how to calculate and apply this impulse is rather complicated and interesting. So read on!
## Linear Collision Response
We now pick up where we left off at the end of the collision detection article.
We have a contact point and a contact normal for the collision.
Lets start by calculating a collision response impulse without rotation.
First, take the dot product of the linear momentum of the go stone with the contact normal. If this value is less than zero, continue; otherwise, the stone is moving away from the board and you should not apply a collision impulse.
To calculate the impulse we need the concept of ‘elasticity’.
If the collision is perfectly elastic the go stone bounces off the board without losing any energy:
If the collision is perfectly inelastic, the go stone loses all its vertical motion post-collision and slides along the surface of the board:
What we want is something in between:
To support this we introduce a new concept called the ‘coefficient of restitution’. When this value is 1 the collision is perfectly elastic, when it is 0 the collision is inelastic. At 0.5, it’s halfway between.
This gives the following formula: $j = -( 1 + e ) \boldsymbol{p} \cdot \boldsymbol{n}$
Where:
• j is the magnitude of the collision impulse
• e is the coefficient of restitution [0,1]
• p is the linear momentum of the go stone
• n in the contact normal for the collision
Note that the direction of the collision impulse is always along the contact normal so to apply the impulse just multiply the contact normal by j and add it to the linear momentum vector.
Here is the code:
void ApplyLinearCollisionImpulse( StaticContact & contact, float e )
{
const float mass = contact.rigidBody->mass;
const float j = max( - ( 1 + e ) * dot( contact.rigidBody->linearMomentum, contact.normal ), 0 );
contact.rigidBody->linearMomentum += j * contact.normal;
}
And here is the result:
## Collision Response With Rotation
Now lets calculate collision response with rotation.
To do this we will now calculate the velocity of the stone at the contact point, then take the dot product of this vs. the contact normal to check if the stone is moving towards the board. This is necessary because the stone is rotating so different points on the stone have different velocities.
Next we use the same basic strategy of applying an impulse along the contact normal with magnitude j except this impulse is now applied to the go stone at the contact point.
It’s actually quite tricky now to calculate the magnitude of this impulse such that the post-collision behavior matches the coefficient of restitution because the impulse at the contact point has both linear and angular effects, and the balance between them depends on the following factors:
• The point of application of the impulse
• The direction of the impulse relative to the center of the stone
• The inertia tensor of the go stone
Here is the general equation for calculating j of the collision response between two moving objects:
You can find an excellent derivation of this result on wikipedia.
Understandably this is quite complex, but in our case, the go board never moves, so we can simplify the equation by assigning zero velocity and infinite mass to the second body. This leads to the following, simpler, but still pretty complex equation:
$j = \dfrac{ -( 1 + e ) \boldsymbol{v} \cdot \boldsymbol{n} } { m^{-1} + ( \boldsymbol{I^{-1}} ( \boldsymbol{r} \times \boldsymbol{n} ) \times \boldsymbol{r} ) \cdot \boldsymbol{n} }$
Where:
• j is the magnitude of the collision impulse
• e is the coefficient of restitution [0,1]
• n in the contact normal for the collision
• v is the the go stone velocity at the contact point
• r is the contact point minus the center of the go stone
• I is the inertia tensor of the go stone
• m is the mass of the go stone
Which turns into the following code:
vec3f GetVelocityAtWorldPoint( const RigidBody & rigidBody, vec3f point ) const
{
vec3f angularVelocity = transformVector( rigidBody.inverseInertiaTensor,
rigidBody.angularMomentum );
return linearVelocity + cross( angularVelocity, point - rigidBody.position );
}
void ApplyCollisionImpulse( StaticContact & contact, float e )
{
RigidBody & rigidBody = *contact.rigidBody;
vec3f velocityAtPoint = GetVelocityAtWorldPoint( rigidBody, contact.point );
const float vn = min( 0, dot( velocityAtPoint, contact.normal ) );
// calculate inverse inertia tensor in world space
mat4f rotation;
rigidBody.orientation.toMatrix( rotation );
mat4f transposeRotation = transpose( rotation );
mat4f i = rotation * rigidBody.inverseInertiaTensor * transposeRotation;
// apply collision impulse
const vec3f r = contact.point - rigidBody.position;
const float k = rigidBody.inverseMass + dot( cross( r, contact.normal ), transformVector( i, cross( r, contact.normal ) ) );
const float j = - ( 1 + e ) * vn / k;
rigidBody.linearMomentum += j * contact.normal;
rigidBody.angularMomentum += j * cross( r, contact.normal );
}
And here is the result:
## Coulomb Friction
We don’t often get to see frictionless collisions in the real world so the previous result looks a bit strange.
In order to get realistic behavior out of the go stone, we need to add friction.
We’ll model sliding friction between the go stone and the board using the Coulomb friction model.
In this model the friction impulse is proportional the magnitude of the normal impulse ‘j’ and limited by a friction cone defined by the coefficient of friction ‘u’:
Lower friction coefficient values mean less friction, higher values mean more friction. Typical values for the coefficient of friction are in the range [0,1].
Calculation of the Coulomb friction impulse is performed much like the calculation of the normal impulse except this time the impulse is in the tangent direction against the direction of sliding.
Here is the formula for calculating the magnitude of the friction impulse:
$j_t = \dfrac{ - \boldsymbol{v} \cdot \boldsymbol{t} } { m^{-1} + ( \boldsymbol{I^{-1}} ( \boldsymbol{r} \times \boldsymbol{t} ) \times \boldsymbol{r} ) \cdot \boldsymbol{t} }$
Where:
• jt is the magnitude of the friction impulse (pre-cone limit)
• u is the coefficient of friction [0,1]
• t in the tangent vector in the direction of sliding
• v is the the go stone velocity at the contact point
• r is the contact point minus the center of the go stone
• I is the inertia tensor of the go stone
• m is the mass of the go stone
Which turns into this code:
void ApplyCollisionImpulseWithFriction( StaticContact & contact, float e, float u )
{
RigidBody & rigidBody = *contact.rigidBody;
vec3f velocityAtPoint = GetVelocityAtWorldPoint( rigidBody, contact.point );
const float vn = min( 0, velocityAtPoint, contact.normal );
// calculate inverse inertia tensor in world space
mat4f rotation;
rigidBody.orientation.toMatrix( rotation );
mat4f transposeRotation = transpose( rotation );
mat4f i = rotation * rigidBody.inverseInertiaTensor * transposeRotation;
// apply collision impulse
const vec3f r = contact.point - rigidBody.position;
const float k = rigidBody.inverseMass + dot( cross( r, contact.normal ), transformVector( i, cross( r, contact.normal ) ) );
const float j = - ( 1 + e ) * vn / k;
rigidBody.linearMomentum += j * contact.normal;
rigidBody.angularMomentum += j * cross( r, contact.normal );
// apply friction impulse
velocityAtPoint = rigidBody.GetVelocityAtWorldPoint( contact.point );
vec3f tangentVelocity = velocityAtPoint - contact.normal * dot( velocityAtPoint, contact.normal );
if ( length_squared( tangentVelocity ) > 0.001f * 0.001f )
{
vec3f tangent = normalize( tangentVelocity );
const float vt = dot( velocityAtPoint, tangent );
const float kt = rigidBody.inverseMass + dot( cross( r, tangent ), transformVector( i, cross( r, tangent ) ) );
const float jt = clamp( -vt / kt, -u * j, u * j );
rigidBody.linearMomentum += jt * tangent;
rigidBody.angularMomentum += jt * cross( r, tangent );
}
}
And gives the following result:
## Rolling Friction
This looks really good but there is one small problem remaining.
Due to its shape, the go stone really prefers to rotate about axes on the xz plane. This means that if you you attempt to spin up around the y axis it stands up and spins on its side like a coin:
This is kinda cool. The problem is that it spins like this forever.
Why? Shouldn’t coulomb friction handle this for us?
No. Coulomb friction only handles friction when the two surfaces are sliding relative to each other.
Sliding friction is just one type of friction and there are many others.
What we have here specifically is combination of rolling and spinning friction.
At this point I have very little patience so I came up with my own hack approximation of spinning and rolling friction that gives me the result that I want: vibrant motion at high energies but slightly damped so the stone slows down, collapses from spinning, wobbles a bit and come to rest.
Here is my horrible code that does this:
// this is a *massive* hack to approximate rolling/spinning
// friction and it is completely made up and not accurate at all!
if ( collided )
{
float momentum = length( stone.rigidBody.angularMomentum );
const float factor_a = DecayFactor( 0.9925f, dt );
const float factor_b = DecayFactor( 0.9995f, dt );
const float a = 0.0f;
const float b = 1.0f;
if ( momentum >= b || appliedSpin )
{
stone.rigidBody.angularMomentum *= factor_b;
}
else if ( momentum <= a )
{
stone.rigidBody.angularMomentum *= factor_a;
}
else
{
const float alpha = ( momentum - a ) / ( b - a );
const float factor = factor_a * ( 1 - alpha ) + factor_b * alpha;
stone.rigidBody.angularMomentum *= factor;
}
}
// apply damping
const float factor = DecayFactor( 0.99999f, dt );
stone.rigidBody.linearMomentum *= factor;
stone.rigidBody.angularMomentum *= factor;
And here is the end result:
# Coming Soon: Digitizing The Go Stone
Donations offset hosting costs and encourage me to write more articles!
Jason March 25, 2013 at 11:18 pm
Great to see such good progress with this project. The stone bounce looks a bit too elastic – the first bounce at 1:10 seems high.
Glenn Fiedler March 25, 2013 at 11:45 pm
Thanks! Yeah I have tuned the elasticity up pretty high. I want really dynamic stone motion so when they drop they do a lot of tumbling.
Obviously, the elasticity really doesn’t come into play much when placing a stone on the board so I’m taking a bit of creative licence with this one
Also, the amount of bounce depends heavily on the angle of hit. Sometimes you get extra high bounces!
Irlan April 10, 2013 at 7:08 pm
Nice article.
float clamp(float x, float min, float max)
{
if(x > max)
return max;
else if(x < min)
return min;
else
return x;
}
correct?
Glenn Fiedler April 10, 2013 at 9:00 pm
I sure hope so
Irlan April 10, 2013 at 9:13 pm
Thanks! I’ve already sent you another question but i’m going to delete and ask here… If we do not apply damping in a rolling ball in the plane, it will be moving forever?
Glenn Fiedler April 10, 2013 at 11:11 pm
Yes without damping or rolling friction it will roll forever
Glenn Fiedler April 11, 2013 at 2:21 am
(Of course some damping/error will accumulate over time — if your integrator loses energy rather than add it may come to rest very slowly on its own)
Irlan April 10, 2013 at 9:10 pm
If we do not apply damping in a rolling ball in the plane, it will be moving forever?
Glenn Fiedler April 10, 2013 at 11:11 pm
Yes if you don’t apply damping or rolling friction it will roll forever | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 3, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.568306028842926, "perplexity": 2908.7058214687368}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368702849682/warc/CC-MAIN-20130516111409-00068-ip-10-60-113-184.ec2.internal.warc.gz"} |
http://nrich.maths.org/5680/solution | ### All in the Mind
Imagine you are suspending a cube from one vertex (corner) and allowing it to hang freely. Now imagine you are lowering it into water until it is exactly half submerged. What shape does the surface of the water make around the cube?
### Just Rolling Round
P is a point on the circumference of a circle radius r which rolls, without slipping, inside a circle of radius 2r. What is the locus of P?
### Coke Machine
The coke machine in college takes 50 pence pieces. It also takes a certain foreign coin of traditional design. Coins inserted into the machine slide down a chute into the machine and a drink is duly released. How many more revolutions does the foreign coin make over the 50 pence piece going down the chute? N.B. A 50 pence piece is a 7 sided polygon ABCDEFG with rounded edges, obtained by replacing AB with arc centred at E and radius EA; replacing BC with arc centred at F radius FB ...etc..
# Weekly Problem 28 - 2007
##### Stage: 3 and 4 Challenge Level:
The two shaded squares are those on which the block began. After the first move, it occupies the squares labelled $1$ (or $1/5$). After the second move, it occupies the squares labelled $2$ and so on. After the fifth and final move, it occupies the squares labelled $5$ (or $1/5$). As can be seen, $19$ squares have been occupied altogether.
This problem is taken from the UKMT Mathematical Challenges.
View the previous week's solution
View the current weekly problem | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7213051915168762, "perplexity": 1548.428600434455}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-42/segments/1414119649807.55/warc/CC-MAIN-20141024030049-00218-ip-10-16-133-185.ec2.internal.warc.gz"} |
http://www.jphellemons.nl/?tag=/HTML | # Macbook air 13” 4mot/4/40000002: exhaust-0
Well the title is clear right? I ran the Apple Hardware Test (AHT) because our model was from 2012.
• Switched off the macbook
• power on macbook
• press and hold ‘D’
I ran the extended and more advance test which takes a bit longer. But it gave me the message:
## 4mot/4/40000002: exhaust-0
it said that the fan was broken. It was exactly what I expected due to the noise of the fan.
Our model was an A1466 and the fan replacement would cost me 145 euro at an Apple care center, so I bought the part online for 26 euro.
Here is the step by step ifixit guide. Please note that you need a P5 pentalobe screwdriver which is Apple specific. I bought it online for 5 euro.
I have spend 38 euro inc shippingcosts. You can get the screwdriver really cheap from aliexpress, but the shipping takes a long time and I cannot live that long without my macbook. Same for the fan it seems. You can get both for 9 dollar without shipping costs but it will take a while to arrive.
On the left is the new one, right side is the old one.
The hardest part was opening the zif connector to reattach the data kabel for the new fan.
The zif connector is so small that it is hard to open.
Running the hardware diagnostics tool can confirm that replacing the fan is a succes. You will not get the 4mot/4/40000002 exhaust error again.
Good luck with the fan replacement!
# Manage users for webform auth missing option in Visual Studio
and then there was this stacktrace and error… I have not had this issue before. It was since the 4.6 frameworkwas installed.
Thankfully I found this stackoverflow answer which resolves it:
in notepad++ and ctrl+g (go to) line 989 and give the string appId the value of “1” instead of the stringutil.blabla
No more error on:
StringUtil.GetNonRandomizedHashCode(String.Concat(appPath, appPhysPath)).ToString("x", CultureInfo.InvariantCulture);
Good luck!
# Calculate km distance between two latitude longitude points from two floats
Having a store locator on my to do list, I started months back with storing the latitude and longitude for the stores in a database. I forked this repository in 2012 https://github.com/bjorn2404/jQuery-Store-Locator-Plugin in order to have something like a store locator on our website. The downside to that store locator is that it is all client side and puts a copy of all your customer data on the internet. It is great data for your competition. So to disclose as little as possible and still serve your valued customers, I decided to do the calculation on the backend. Closest to the data. So that would be on the SQL server.
SQL Server has datatypes like points and geometry since 2008. With this SQL statement you can get the distance between my location
##### lat 51.69917 lng 5.30417 and the locations in the stores table.
SELECT top 10 StoreID
,StoreName
,StoreLatitude
,StoreLongitude
,StoreCity
,round((geography::Point(StoreLatitude, StoreLongitude, 4326).STDistance(geography::Point(51.69917, 5.30417, 4326))) / 1000, 1) as km
FROM STORES
where StoreLongitude < 150 and StoreLongitude > -150 and StoreLatitude < 90 and StoreLatitude > -90
order by (geography::Point(StoreLatitude, StoreLongitude, 4326).STDistance(geography::Point(51.69917, 5.30417, 4326)))
The third parameter for the point data type is 4326 which is an enumeration:
And about 4326 SRID. It also called WSG84(http://en.wikipedia.org/wiki/World_Geodetic_System) system. It's the most common system to represent point on spherical(not flat) earth. It uses degree,minute,second notation and it's x and y coordinates are usually called latitude and longitude.
SRID (Spatial Reference System Identifier) : https://en.wikipedia.org/wiki/SRID
This post is more of a reference for me to lookup how to calculate distances on the Microsoft SQL server in SQL. But maybe it helps others too.
Good luck!
Yesterday 9 September 2015 a three year old comic became reality:
Jun 19, 2012 source http://hijinksensue.com/comic/surface-tension/
Apple released the Ipad Pro. It is a larger screen similar to the surface dimensions and a keyboard in the cover like the surface and has pen input like the surface.
26 oktober 2012 Microsoft released the Surface RT. A tablet with pen input, keyboard cover etc. The OS is not the full Windows version (just like the iPad pro now)
The pro edition of the surface did have a full version.
This is not the first time that apple claims to have a new product. Back in 2000 Bill Gates had a Lenovo tablet with monochrome screen:
two years later he had a Fujitsu tablet with a color screen and Windows XP (2002)
Besides tablets, there were mobile devices. PDA’s running Windows Mobile The predecessor of Windows Phone as we know it today.
Pocket pc started around 2000 and became Windows Mobile in 2002. I have had devices with applications to send mail and browse the web. run games etc. before the launch of the first generation of iPhones.
Steve Jobs said back in 2007 when they released the very first iPhone:
“Who wants a stylus? You have to get em', put em' away. You lose them. Yuck.”
But back on topic: the iPad pro is less than I expected. I expected it to run full mac OS X el captain. But the OS is not optimized for touch input. So it seems that Apple will run iOs and OS X side by side for a few more years. Microsoft made the step when moved from Windows Phone 7 to 8 to run everything on the same kernel. It is a hard step. A lot of people fell over it. But it was necessary and really inevitable. But today all (or almost all) Windows Phone 8.x devices will have the Windows 10 update and will run the same apps on their phone as on their laptop/desktop as on their Xbox. This whole concept will be copied by Apple in a year or two maybe three and will be sold like they invented it.
Please do not get me wrong, I like Apple and like their design, usability and the way that the hardware is sold together with the software. The way they update their mobile devices. I like that more then Androids by the way. But the thing that I dislike is that their marketing is so good that less tech aware people believe that Apple invented the wheel and those people share their view with even more tech aware people who assume they are right. But when the Apple fans encounter someone with more technical knowledge they often avoid a discussion.
# When you forget to set a column to auto increment in SQL Server
If you add a new table and mark the ID column as primary key, but you forgot to set the int or bigint to auto increment, you can not fix this in the SQL Management Studio.
There are several ways to do this, I ended up removing the primary key, dropping the column and re-creating it.
Dropping the column also gave me the error about dropping the whole table and re-creating it. So I had to do this with some SQL, so no GUI today but just these two small SQL statements. I hope it helps, otherwise it is just an online backup for when I forget how I fixed this.
alter table YOURTABLENAME add YOURCOLUMNNAME bigint IDENTITY(1,1) primary key
alter table YOURTABLENAME drop column YOURCOLUMNNAME
Good luck!
ps. when you use select @@version you get to see what version of SQL server you are using. I had
Microsoft SQL Server 2008 (SP3) - 10.0.5520.0 (X64)
Jul 11 2014 16:11:50 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16182443499565125, "perplexity": 2487.32721213159}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-07/segments/1454701161775.86/warc/CC-MAIN-20160205193921-00149-ip-10-236-182-209.ec2.internal.warc.gz"} |
http://dgtal.org/doc/nightly/moduleNumber.html | DGtal 0.9.4beta
Number and Integer Concepts
# Overview
When implementing digital geometry algorithms, the choice of integer type to implement or approximate $$Z$$ is crucial in many situations. In DGtal, objects, datastructure and algorithms are orthogonal to this choice in the sense that the user can specify the best Integer type for his own pruposes.
First of all, approximation with built-in integer types with bounded ranges can be considered. For example, DGtal::int32_t defines OS independent 32 bits signed integers.
If more precision is required and if GMP (Gnu multiprecision library) is available, DGtal::BigInteger defines arbitrary precision integers. In this case, performances can be impacted.
As detailed in the Digital Spaces, Points, Vectors and Domains documentation, the integer type choice is specified as template parameter of templated classes (e.g. SpaceND). The main constraint on the type is that it induces a commutative ring with identity for the classical addition, and multiplication operators.
# Number and Integer Concepts
In many DGtal classes, we control user specified template type thanks to concept checking mechanisms. In many situations, when using a template type associating with numbers, following basic concepts are involved:
Concept name Short description Model examples
concepts::CSignedNumber Signed numbers DGtal::int32_t, double, ....
concepts::CUnsignedNumber<td>Unsigned numbers DGtal::uint32_t,...
concepts::CBoundedNumber Numbers with bounded capacity DGtal::int64_t, ... (but not BigInteger)
concepts::CIntegralNumber Integral numbers DGtal::int64_t, BigInteger,...
When we want to perform some computations on these numbers, we may use the following concepts:
Concept name Short description Model examples
concepts::CCommutativeRing the model can be associated to a commutative ring (operators +,-,*, ....) DGtal::int32_t, double, ....
concepts::CEuclideanRing Refinement of concepts::CCommutativeRing with a "/" operator DGtal::int32_t, double, .....
concepts::CInteger Refinement of both concepts::CEuclideanRing and concepts::CIntegralNumber DGtal::int32_t, .....
# Basic integer types and NumberTraits
First of all, BasicTypes refines in DGtal classical built-in integer types such as DGtal::uint64_t or DGtal::int32_t. However, not all these types are models of the concept concepts::CCommutativeRing. Indeed, DGtal::uint64_t has no inverse for the addition operator.
Hence, if we have a templated class SpaceND with two arguments: a static dimension and a type of integer. And if we add a constraint that the integer type must be a model of concepts::CCommutativeRing, the following code:
will produce a compiler error.
In DGtal algorithms, we sometimes need information or associated types attached to a integer type. NumberTraits structure is used to decorate integer types with tags (e.g. NumberTraits<T>::IsSigned), associated types (e.g. NumberTraits<T>::UnsignedVersion), constant values (e.g. NumberTraits<T>::ONE and NumberTraits<T>::ZERO), or conversion functions (e.g. NumberTraits<T>::castToDouble()). | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.42353877425193787, "perplexity": 4537.1726520821385}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-51/segments/1512948563629.48/warc/CC-MAIN-20171215040629-20171215060629-00213.warc.gz"} |
http://astronomy.stackexchange.com/users/1050/stevenvh?tab=summary | # stevenvh
less info
reputation
8
bio website stevenvh.net/steven.php location Flanders, Belgium age 54 member for 7 months seen yesterday profile views 3
That's "Steven" (with the "n" at the end)
"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." — Bertrand Russell
Product designer, consumer electronics: audio (with Philips), home automation.
Done computer science in a previous life too.
Belbin team roles: Plant and Resource Investigator
Personal values: respect, honesty, pride, modesty, fairness
I yell because I care
favorite candy
7 Did atoms in human body indeed come from stars? 4 Do black holes die? 3 Why do objects burn when they enter earth's atmosphere? 3 if the big bang only expanded the universe when and how did it originate? 2 Is the light we see from stars extremely old?
# 368 Reputation
+10 How certain are we about the universe's flatness? +10 Is there matter forming in the inflationary space? +10 Did cosmological inflation occur at speeds greater than $c$? +10 Did atoms in human body indeed come from stars?
# 3 Questions
2 How certain are we about the universe's flatness? 2 Did cosmological inflation occur at speeds greater than $c$? 0 Free neutrons and stellar nucleosynthesis
# 14 Tags
9 star × 2 2 light 4 black-hole 2 distances 3 big-bang-theory 1 cosmological-inflation × 2 3 atmosphere 1 dark-matter 2 speed 1 star-formation
# 32 Accounts
Electrical Engineering 106,870 rep 8326545 Mathematica 2,905 rep 11141 Stack Overflow 1,301 rep 21737 Mathematics 775 rep 1722 German Language 642 rep 215 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2975003123283386, "perplexity": 10851.396839591356}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657134620.5/warc/CC-MAIN-20140914011214-00031-ip-10-234-18-248.ec2.internal.warc.gz"} |
https://mathoverflow.net/questions/118505/are-maximal-connected-semisimple-subgroups-automatically-closed | # Are maximal connected semisimple subgroups automatically closed?
(Yet another question in a series demonstrating my rather embarrassing ignorance of standard Lie theory... I hope this is not too basic for MO!)
To be a little more precise: let $G$ be a real connected Lie group, not necessarily simply connected, and let $R$ be its solvable radical. Then (see the EOM entry, for instance) $G$ can be written as $R\cdot S$ for some maximal semisimple, connected Lie subgroup $S$. Having looked online, I get the impression that $S$ need not be closed. Is this impression correct?
(As mentioned in the link above, if $G$ is simply connected then a Levi--Malcev decomposition of its Lie algebra exponentiates to give $G=R\rtimes S$ and $S$ is closed.)
The motivation is in some joint work, where we have a property of locally compact groups that is known to pass to closed subgroups, and which we have shown is not satisfied by any connected semisimple Lie group. It would be nice if we could deduce from this that a connected Lie group with this property has to be solvable...
• If by a Lie subgroup you mean that $S$ has the induced topology, then every Lie subgroup is closed, since the complement of $S$ in its closure is a union of orbits, and all orbits are submanifolds of the same dimension. Jan 10, 2013 at 8:52
• @Angelo: perhaps my terminology is incorrect or ambiguous. I meant that $S$ is an immersed submanifold of $G$ (as in Alain Valette's answer). Jan 10, 2013 at 22:56
Your impression is correct. Let $H$ be the universal cover of $SL_2(\mathbb{R})$, it has infinite cyclic center, let $z$ be a generator of the center. Consider the product $H\times U(1)$ (where $U(1)$ is the group of complex numbers of modulus 1), and mod out by the (discrete, central) subgroup generated by $(z,e^{2\pi i\theta})$, where $\theta$ is irrational. You get a reductive group with radical $S^1$, in which the Levi factor $H$ is dense. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.928867757320404, "perplexity": 105.53399702817549}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103619185.32/warc/CC-MAIN-20220628233925-20220629023925-00288.warc.gz"} |
https://www.tutorialspoint.com/how-to-draw-different-shapes-using-the-python-turtle-library | # How to draw different shapes using the Python Turtle library?
PythonNumpyServer Side ProgrammingProgramming
In this program, we will draw different shapes using the Turtle library in Python. Turtle is a python feature like a drawing board, which lets you command a turtle to draw all over it. The different shapes that we are going to draw are square, rectangle, circle and a hexagon.
## Algorithm
Step 1: Take lengths of side for different shapes as input.
Step 2: Use different turtle methods like forward() and left() for drawing different shapes.
## Example Code
import turtle
t = turtle.Turtle()
#SQUARE
side = int(input("Length of side: "))
for i in range(4):
t.forward(side)
t.left(90)
#RECTANGLE
side_a = int(input("Length of side a: "))
side_b = int(input("Length of side b: "))
t.forward(side_a)
t.left(90)
t.forward(side_b)
t.left(90)
t.forward(side_a)
t.left(90)
t.forward(side_b)
t.left(90)
#CIRCLE
#HEXAGON
for i in range(6):
t.forward(side)
t.left(300)
## Output
SQUARE:
Length of side: 100
RECTANGLE:
Length of side a: 100
Length of side b: 20
CIRCLE: | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2203393578529358, "perplexity": 9249.076286877615}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046152168.38/warc/CC-MAIN-20210727010203-20210727040203-00269.warc.gz"} |
https://schneide.blog/author/fwellen/ | # Inductive types on the rise
One thing I really got used to when using Agda for academic projects are inductive types. And inductive types are probably what I currently miss most when using mainstream languages to solve practical problems.
This Post is aimed at software developers that do not know inductive types (Agda, Coq, Idris), variants (OCaml, F#) or GADTs (Haskell). Other software developers might still be interested in the last section about higher inductive types.
### What are inductive types?
I will use Agda’s syntax for the most part. Here is a simple example of an inductive type named ‘Bool’:
The colons are to be read as ‘is of type’ and ‘Set’ is the type of types. The code defines an inductive type named ‘Bool’ with the constructors ‘True’ and ‘False’. I use ‘constructor’ with a broader meaning than it has in object oriented programming.
The type ‘Bool’ will behave somewhat like the following enum in Java:
The analogy with ‘enum’ works as long as the constructors have zero arguments. Here is an inductive type where one constructor has one argument:
For any type ‘A’, ‘Optional A’ will be a type that behaves like an immutable version of ‘Optional<A>’ in Java. So for example, ‘Some True’ would be a value of type ‘Optional Bool’ (Note that function application is written without parenthesis). It is also possible, to have constructors with arguments of the type to be defined:
The natural numbers defined in this way will be great for verification and very bad for actual calculations since this representation is unary. For example, the number three can be defined with three constructor calls:
The really interesting thing to note is, that this quite short inductive definition of the natural numbers actually behaves like the natural numbers from mathematics. And you can prove things about those naturals using the same induction based proofs you learn mathematics courses. In Agda, those proofs can be done using pattern matching, the topic of the next section.
In Agda, inductive definitions are also supported for dependent types. There are lots of interesting things that can be done using this combination of concepts. One is an inductive definition of equality for all types. This won’t give you a reasonable ‘Equals’-method for all your types, but it provides you with a consistent notion what such a method should return.
### Patterns
The great thing about inductive types is, that functions may be defined by pattern matching. A simple case is the negation function on the type ‘Bool’ defined above:
The first line declares the type of the new function ‘negation’ to be ‘Bool -> Bool’ and the lines below are a definition by pattern matching. Agda checks if the pattern covers all cases. If you want the same compile time check in Java (prior to version 12) you would have to use a trick.
Here is an example using the types defined above, with a more complicated pattern:
Note that ‘IsEven’ is recursively used in the last line. The termination checker of Agda makes sure that the recursion doesn’t loop forever and this definition passes this check, since ‘n’ is of a lower ‘height’ than the argument ‘Successor (Successor n)’. So progress will be made on each recursion and the computation will stop eventually.
Those checks are important when pattern matching is used to prove things, which can be done for example in the style of the following pseudo code:
### Higher inductive types
In mathematics new sets are often created by identifying elements of some easy to understand set. For example, the rational numbers can be constructed as pairs of integers ‘(a,b)’, where b is not zero, by identification of pairs ‘(a,b)’ and ‘(c,d)’ if ‘c*b = a*d’.
It is now possible in some systems to construct such quotients as inductive types. Agda has a special mode called ‘cubical’ which allows inductive types to have constructors that ‘produce’ equalities in the inductive type. Here is an excerpt from the standard library for Agda’s cubical mode, that defines the rational numbers inductively:
The first constructor ‘con’ tells us, that we can produce a rational number from a pair of integers ‘u’ and ‘a’ provided ‘a’ is not zero. The constructor ‘path’ makes the identification explained above. The third constructor ‘trunc’ has to do with some curious weirdness that comes with having ‘inductive equalities’ – some elements of a type might be equal in different ways. ‘trunc’ uses inductive equalities again, to ‘truncate’ the possibilites how rational numbers can be equal back to the expected ‘yes’ and ‘no’.
This appearance of extra equalities between things is by no means a pathology, but a connection to a topic in pure mathematics called homotopy theory. But so far there are not much suggestions how the homotopy theory we have at our fingertips in Agda can help us with pratical programming. If we ‘trunc’ our quotient however, we have a pretty usable way of mimicking the mathematical style described above when defining data types.
As more and more concepts from academic languages pour into the mainstream, I have hopes that I can use at least some inductive techniques some day, saving me from some annoying bugs and hard to read constructions.
# Compiling and using Agda through the Windows Linux Subsystem
The Windows Subsystem for Linux (WSL) more or less runs a linux kernel on Windows 10. In this post, I will describe how to use WSL to compile and run Agda, a dependently typed functional programming language. Compiling agda yourself makes sense if you want to use the latest features, of which there are quite nice ones. The approach presented here is just my preferred way of compiling and using Agda on a Linux system with some minor adjustments.
## Prerequisits for compiling
First, you need the “ubuntu app”, you can install it following this guide. Essentially, you just have to activate WSL and install the app through the Microsoft Store, but following the guide step by step allowed me to do it without creating a Microsoft account.
After installing your ubuntu app will ask you to create a new account and it will probably need some updating, which you can do by running:
sudo apt-get update
A usability hint: You can copy-paste to the ubuntu app by copying with CTRL-C and right-clicking into the ubuntu-window. You have to make the ubuntu-window active before the right-click. You can copy stuff in the ubuntu-window by marking and pressing CTRL-C.
There are two tools that can get the dependencies and compile Agda for you, “cabal” and “stack”. I prefer to use stack:
https://docs.haskellstack.org/en/stable/README/
After installing, stack asked me to append something to my PATH, which I did only for the session:
export PATH=$PATH:/home/USER/.local/bin ## Getting the sources and compiling Git is preinstalled, so you can just get the agda sources with: git clone https://github.com/agda/agda.git Go into the agda folder. It will contain a couple of files with names like stack-8.8.1.yaml These are configuration files for stack. The numbers indicate the version of ghc (the haskell compiler) that will be used. I take always the newest version (if everything works with it…) and make a copy cp stack-8.8.1.yaml stack.yaml – since stack will just use the “stack.yaml” for configuration when run in a folder. Now: stack setup will download ghc binaries and install them somewhere below “HOME/.stack/”. Before building, we have to install a dependency (otherwise there will be a linker error with the current ubuntu app): sudo apt install libtinfo-dev Then tell stack to build and hope for the best (that took around 5.2GB of RAM and half an hour on my system…): stack build On success, it should look like this: If you are not confident with finding the locations from the last lines again, you should secure the path from the last lines. We will need “agda” and “agda-mode”, which are in the same folder. ## Using Agda Of course, you can use agda from the command line, but it is a lot more fun to use from emacs (or, possibly atom, which I have not checked out). Since the ubuntu app does not come with a window system and on the other hand our freshly built agda cannot be invoked easily from windows programs, I found it most convenient to run emacs in the ubuntu app, but use an x-server in windows. For the latter, you can install Xming and start it. Then install emacs in the ubuntu app: sudo apt install emacs Before starting emacs, we should install the “agda-mode” for emacs. This can be done by ./stack/install/[LONG PATH FROM ABOVE]/bin/agda-mode setup Now run emacs with the variables “DISPLAY” set to something which connects it to Xming and “PATH” appended by the long thing from above, so emacs can find agda (and agda-mode): PATH=$PATH:~/agda/.stack-work/[LONG PATH FROM ABOVE]/bin/ DISPLAY=:0 emacs
Then everything should work and you can test the agda-mode, for example with a new file containing the following:
CTRL-C, CTRL-L tells agda-mode to check and highlight the contents of the file. Here is more on using the agda-mode. Have fun!
Sources:
# A new star in software verification?
F* (pronounced F star) is a functional programming language with a dependent type system that supports verification. What follows is a story about my experiences with F* and a concluding opinion why languages like F* could be useful for the working software developer.
There is a big project using F* and related tools for the ambitious goal to build a verified implementation of TLS.
So far, judging from the website, there is a verified efficient implementation of the relevant cryptographic primitives but their implementation of the protocol is not yet verified. That is certainly already a great achievement and got me interested F*.
## Setting it up
There is a F*-Tutorial which comes with an online editor, which is great if you just want to play a bit with the language. You don’t have to install anything, provided you have a recent mainstream browser. The tutorial is fun to do, but after I spent some time on it, I wanted to know what it is like to use F* not on a prescribed path.
Sooner or later, you probably want to install it on your machine, which is not a problem at all, if you are on linux system and an emacs user. There is a binary and an emacs mode which is also easy to install on windows but the combination was somehow forbiddingly slow on my (fast) machine. In the following, pictures will show excerpts from the emacs-mode.
## Programming in F*
Let me first show you, what programming in F* looks like. Here is a definition of the commonly known (higher order) function “filter” which takes a predicate (function to bool in this case) and a list and returns the “sublist” of all things on the list matching the predicate:
The arrows and strange dots are just “->” and “::” rendered by the emacs mode. Otherwise, it is exactly the pattern matching definition that would also work in OCaml or F# (where you can write exactly the same thing):
The second argument “l” is matched against the two things a list might be, either the empty list “[]” or a list with consisting of some first element “x” and a list “xs”. In the first case, we are done and in the second case we decide if “x” should be in the result list and recursively call “filter” to deal with the “xs”.
The type of “filter” can be inferred by F*, but we could have declared it before the definition like this:
The alpha is really fancy emacs-mode rendering for ” ‘a ” and stands for an arbitrary type. This is also the type F* would infer, since what we did does not require anything special from the element type of the lists.
So the declaration says that our function takes some predicate “p” a list of things p may be applied to and returns a list of the same type just with “Tot” written in front of it. The latter tells us, that filter is a total function, i.e. it terminates and will not throw an exception (I guess there is a bit more to it, but so far that explanation worked well for me). There is also a modifier “ML” which would tell us, that the function behaves like a function in OCaml – so it could throw runtime exceptions or loop forever. After introducing you to some verification features, I will tell you why this distinction is important here.
Let us first rewrite our declaration a bit:
I replaced the alpha with a fixed type, the natural numbers (that will simplify things…) and introduced variables “p” and “l” that we can use now to construct types. What kind of types? Well, in this case, I want to construct a replacement for “(list N)” which tells us a bit more about the result of filtering a list. One reason to have types is to make sure, that the result of some construction meets a specification. Usually these kinds of specifications are quite coarse and might just tell you, that the result is an integer. So far, the specification of the filter function only tells us, that the result will be a list of natural numbers. In F*, we can do a lot more. The following specifies the result of filter to be the sublist of all elements of “l” that satisfy “p”:
Between the curly braces, I put a formula in predicate logic, which describes this specification. The ” ” is a logical “and”, the “∀” is the “forall” from math and ” element x l’ ” is some function which evaluates to true if x is an element of l’ and false if this is not the case.
Now, one of the things that make me happy when playing with F* is that the definition of filter I gave in the beginning checks against this new declaration as is. This is due to F* using a problem solver to prove that our specification is satisfied and the not-so-random coincidence that to prove the formula, you can use the same structural induction on the list as we used to recursively define “filter”.
For completeness, here is my definition of “element”:
The “#a:eqtype” means, that “a” is some type such that comes with a total equality function for terms of type “a”. The natural numbers used above are such an “a”. Btw: Those natural numbers are not limited in size, like e.g. “unsigned int”. They behave a lot like “BigInteger” in some languages and are certainly not fast, but they are good for proving things.
And now, I should tell you, that the declaration of “filter” which nicely specified what filter does, is probably not what you should do. In fact, it is usually better to split things into definitions and “Lemma”s. So here is again the original definition of filter (with inferred type) and a Lemma about it:
The “Lemma” is again like “Tot” above – it modifies the type. Technically, “filter_specification” is a function, but the only thing important here, is if its definition (“let rec filter_specification = […]”) type checks with the declaration (“val filter_specification […]”) given – because that means that the definition is a proof of the proposition encoded in the declaration. In particular, it is not important what this function returns. In fact, “Lemma” produces a type all of whose terms are equal.
## Verifying Project Euler exercises
First thing I usually do when checking out a new programming language is to solve a couple of Project Euler exercises to get fluent in the basic constructions. So, I thought, why shouldn’t I try the same with F* and prove something about my solution code?
Problem 1 asks us to add all multiples of 3 and 5 below 1000. Usually, my mind drops the “below” and I get a wrong result. But not so this time! Here is my definition of the natural numbers below 1000, which produces the correct list of numbers, since specifying precisely what it is made me read the problem text very carefully:
Now, “naturals_below_1000” is specified by its type, which turned out to work well in this case, since it is not a general purpose function I will reuse.
Now for the task at hand, we need to filter numbers that are multiples of 3 or 5. I took the liberty to equivalently say, numbers divisible by 3 or 5:
I used modulo arithmetic “%” defined in some library to have an easy definition of “divides”. Also note, that I use definitions in proving that I defined the correct list. Both are a bit fishy if I were to claim that I proved some term in my program meets some mathematical definition commonly used for the concepts in the problem text. So you could call that lazy or efficient according to taste.
Now, the number which the exercise asks for can be defined:
F* can not just check if everything is correct but also evaluate expression. In particular the expression “ex1” which turns out to be the correct answer to the problem.
## Is it of use for the working software developer?
I used Scala some years ago to develop a large prototype and, while there were some pains, it worked about as well as expected and I’m quite sure it would have been less fun and less efficient to use Java for the same project. One important point in the decision to use Scala was the possibility to use Java libraries.
F# has the same kind of advantage and I learned to love its type system from OCaml, which apparently was the basis for F#. So for the same reasons that made Scala work for me when constructing prototypes, I could decide to use F# in similar situations. I don’t know, how realistic my hope is, that F* can be used on top of F# one day, but that would be a great improvement over just having F# which is already something I look forward to. So far, it as possible to extract F# code from an F* program.
Usually, tools like F* are thought of and presented as tools to effectively prevent bugs, i.e. catching all of them no matter the effort. I think, what we need for our daily programming tasks are tools for preventing bugs efficiently. My guess is, that dependent types in a practical language like F# are such a tool. This is of course a heavily biased view, since I have a background involving some dependent type theory, which makes me blind to the effort of learning how dependent types work.
One problem with dependently typed languages is, that small changes can break lots of proofs that took effort to prove. This is particularly bad, if you spell out the proofs in all detail and it means refactoring can become quite expensive.
From what I have seen, the use of a problem solver when type checking reduces this problem quite a bit, so this might not be a real issue here and with other dependently typed languages that do something similar. And of, substitute technologies that achieve similar goals, like unit tests or comments, also increase refactoring work.
So ultimately, apart from the fun, I also look forward at using F* as tool. As I mentioned before, I already knew about dependent types and could translate what I see when learning F*, so I can’t tell you how much effort it takes, if you don’t already know those things. But what I can tell you is, that learning dependent type theory was certainly among the most rewarding scientific experiences in my life, so maybe you want to do that anyway.
# There are more exact numbers than you might know
There are lots of annoying problems a programmer can run into, when working with the inexact floating point numbers supported by common cpus. So the idea of using rational numbers
$\frac{n}{d}$
with arbitrary size integers $n,d$ for floating point computation can be quite appealing. However, if you really try this in practice, you are likely to end up with unacceptable performance (for an example, see the post The Great Rational Explosion on this blog).
Another problem with the rationals is, that they don’t support lots of mathematical operations. For example, any prime will not have a rational square root and numbers like $\pi$ and $e$ are not rational.
This post is about the problem of the missing square roots. I will sketch how the rationals can be extended by some specific real numbers. The focus is on what can be done and not how it can be done.
The point of the following example is that we can extend the rational numbers by some new numbers such that we have the square root of 2 and are still able to perform the basic arithmetic operations, i.e. addition, subtraction, multiplication and division by non-zero numbers. And of course, we still want to have the absolute exactness of the rationals.
To achieve this goal, our new numbers can be represented as tuples $(a,b)$ of rational numbers $a,b$. The idea is, that $(a,b)$ stands for the real number
$a+b\sqrt{2}$
And now, a small miracle happens: If you have two of those new numbers then all of the basic arithmetic operations are again given as one of our new numbers! You can believe me or just check this for yourself now. So in total, we have extended the realm of exact calculation to real numbers which are of the form
$a+b\sqrt{2}$.
This is admittedly a bit lame, since we are still far away from calculating general square roots. But the miracle mentioned above is actually not so small and happens in way more generality: The real number $\sqrt{2}$ that we added to the rationals is the solution of the polynomial equation
$X^2=2$ or equivalently $X^2-2=0$
and we can do the same thing with any irrational real number that is the solution of some polynomial equation
$a_n X^n + a_{n-1} X^{n-1} + \dots + a_1 X^1 + a_0 = 0$ or $P(X)=0$
(where $a_n,\dots,a_0$ are rational numbers).
For this general construction, the polynomial above has to be chosen such that $n$ is as small as possible. Then the new numbers can be represented as tuples of length $n$. For the basic arithmetic operations, we think of a tuples $(b_n,\dots,b_0)$ as the polynomial
$b_n X^n+\dots b_1 X^1 + b_0$
and define addition to be addition of those polynomials. To multiply two tuples, take the product of the polynomials and its remainder on division by $P$. You can check out how this recipie does the right thing in the example with $P=X^2-2$. To avoid confusion, let us put the polynomial defining in which extension of the rationals we are into the number. So know, a number is a tuple
$(P,b_n,\dots,b_0)$.
In particular, there are extensions that contain a square root of an arbitrary rational. But if we look at, say, $\sqrt{2}$ and $\sqrt{3}$ we will get two extensions. So we have $\sqrt{2}$ and $\sqrt{3}$ but we can’t do anything that involves both of them. Or in other words, if we have two numbers, $(P,b_n,\dots,b_0)$ and $(Q,c_m,\dots,c_0)$ we don’t know how to perform basic arithmetic unless $n=m$ and $P=Q$.
Here is an easy way to fix this: If we take a step back, we can realize that everything we did above doesn’t need specific features of the rational numbers. The basic arithmetic operations are enough. So we can apply the construction of new numbers including some root to an extension of the rationals. For the problem mentioned above, that would give us tuples of the form
$(X^2-3, (X^2-2, a, b), (X^2-2, c, d))$
– now with four rational numbers $a,b,c,d$.
The corresponding general pattern for an extension (of some extension …) is:
$(P, a_0,\dots, a_n)$
Where the numbers $a_i$ are from some fixed extension and $P$ is a polynomial with coefficients from this fixed extension. We also have to make sure, that $P$ has a property called irreducible. It means that $P$ has at least degree 1 and there is no pair of polynomials $Q,R$ with lesser degree (and coefficients in the extension) such that their product $P\cdot R$ is equal to $P$. If this is not the case, weird things will happen.
Note that if we keep extending our numbers on demand, we can now get square roots of everything, in fact, this even works for square roots of negative numbers. But there are some unmentioned problems, if we want to mix numbers from different towers of extensions. On the other hand, there are also lots of unmentioned possibilites: These construction are pretty general and they can also be applied to finite fields or some extension of the rationals which contains a trancendent element like $\pi$. But I will stop here since my goal of showing some exact representations of numbers that surprised myself once, is reached.
If you want to learn more about the mathematical background, this pdf might help. There is also a way to join two extensions to one of the form we discussed here, the key is this nice theorem: Primitive Element Theorem. There are lots of nice mathematical facts in this area. My former Algebra working group in Karlsruhe, in particular Fabian Ruoff, kindly reminded me of some of them over lunch, when I was discussing the topics of this post.
Then, there are of course implementations. Here is a class in the cgal library for square roots. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 41, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6851435899734497, "perplexity": 554.8138798146286}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250591763.20/warc/CC-MAIN-20200118023429-20200118051429-00508.warc.gz"} |
https://2022.help.altair.com/2022.1/activate/business/en_us/topics/reference/oml_language/ElementaryMath/gcd.htm | # gcd
Returns the greatest common deviser of the set x.
## Syntax
g = gcd(x1,x2,...)
[g,v1,...] = gcd(x1,x2,...)
## Inputs
x1,x2,...
The elements to find the greatest common divisor of.
Type: double | integer
Dimension: scalar | vector
## Outputs
g
The greatest common divisor of the set.
Resulting scalar | vector
v1,...
Vectors containing integers that, when multiplied by the corresponding x elements and summed up, are equal to the greatest common divisor g.
Resulting scalar | vector
## Example
Simple gcd example:
gcd([20 44], [8 11])
ans = [Matrix] 1 x 2
4 11
Simple gcd example:
[g,v1]=gcd([20 44], [8 11])
g = [Matrix] 1 x 2
4 11
v1 = [Matrix] 1 x 2
1 0 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5349422693252563, "perplexity": 11187.759842296597}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296944606.5/warc/CC-MAIN-20230323003026-20230323033026-00037.warc.gz"} |
https://www.statstutor.net/downloads/question-2000009-descriptive-statistics/ | # Question #2000009: Descriptive Statistics
Question: A sample of 36 eggs is taken by the owner of chicken farm. He measures a mean weight of 30 grams with a standard deviation of 3 grams. The standard deviation of the mean weight is…??
Solution: The solution consists of 72 words (1 page)
Deliverables: Word Document
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http://physics.stackexchange.com/questions/13259/evidence-on-the-equation-of-state-for-dark-energy | # evidence on the equation of state for dark energy?
If dark energy contributes mass-energy density $\rho$ and pressure $p$ to the stress-energy tensor, then you can define $w=p/\rho$, where $w=-1$ gives a cosmological constant, $w<-1$ gives a big rip, and $w<-1/3$ if we want to use dark energy to explain cosmological acceleration. The WP "Big Rip" article cites a paper that dates back to 2003 http://arxiv.org/abs/astro-ph/0302506 , which states that the empirical evidence was at that time only good enough to give $-2 \lesssim w \lesssim -.5$.
Have observations constrained $w$ any more tightly since 2003?
I've heard many people express the opinion that $w<-1$ is silly or poorly motivated, or that "no one believes it." What are the reasons for this? Other than mathematical simplicity, I don't know of any reason to prefer $w=-1$ over $w\ne -1$. Considering that attempts to calculate $\Lambda$ using QFT are off by 120 orders of magnitude, is it reasonable to depend on theory to give any input into what values of $w$ are believable?
-
Combining with previous measurements of the acoustic scale, we obtain a value of $w_0$ = -1.03 +/- 0.16 for the equation of state parameter of the dark energy
cited here : Cosmology today–A brief review (25 pages on Theory and data, 2007/Jul)
You can find a new model of the Universe without Dark Energy here:
A self-similar model of the Universe unveils the nature of dark energy (21 pages Jul/2011, not peer-reviewed, it uses only Newton and Coulomb laws). I do not know how this novel viewpoint can be discarded.
Argument:
From $$F=m\cdot a,\, F=G\cdot\frac{m_{1}\cdot m_{2}}{d^{2}},\, F=\frac{1}{4\pi\varepsilon_{0}}\cdot\frac{q_{1}\cdot q_{2}}{d^{2}},\, c=\frac{1}{\sqrt{\varepsilon_{0}\mu_{0}}}.$$ obtain the dimensional equations $$\left[G\right]=M^{-1}L^{3}T^{-2},\left[\varepsilon\right]=M^{-1}Q^{2}L^{-3}T^{2},\left[c\right]=LT^{-1}$$ because the the sum of the exponents is zero, a cute coincidence ;), we know that $[M],[Q],[L],[T]$ can scale in the same way and $[c],[G],[\varepsilon]$ are constants. If the universe can scale thru time, keeping always the same basic physical laws, it will scale.
The scaling law $\alpha(t_{S})=e^{-H_{0}\cdot t_{S}}$ is derived from the observational data, where $t_S$ is considered from the viewpoint of a comoving invariant referential, and Dark Energy is absent from it.
The accelerated expansion is an artifact of the standard model
The statement that space expansion is accelerating is not the result of some direct measurement more or less independent of the cosmological model but, on the contrary, it is a consequence of the theoretical framework of the standard model. The deceleration parameter at the present moment, $q_{0}$, in the $\Lambda$CDM model, for flat space and $\Omega_{R}=0$ , is given by $q_{0}=\frac{1}{2}\left(\Omega_{M}-2\Omega_{\Lambda}\right)$ therefore, for $\Omega_{M}+\Omega_{\Lambda}=1$ , the value of $q_{0}$ is negative for $\Omega_{\Lambda}>1/3$ ; a value of $\Omega_{\Lambda}$ lower than 1/3 leads to a comoving distance largely in disagreement with observations, hence, in the framework of $\Lambda$CDM model it has to be $\Omega_{\Lambda}>1/3$ and, so, $q_{0}<0$ .
(Needless to say: this is my preferred viewpoint because it has no free lunches: growing space, growing dark energy, and apply to all scales, even to Solar system)
-
Thanks for the reference to the Carnero paper -- that's exactly what I was looking for! If your answer had stopped there, I would have accepted and upvoted. But the Oliveira paper is pure crackpottery. – Ben Crowell Aug 8 '11 at 16:09
I would still be interested in posts as to why Big Rip scenarios seem not to be taken seriously by so many people. – Ben Crowell Aug 8 '11 at 16:29
@Ben Crowell I used a few lines to present the 'argument' that a scaling model is inscribed in the gravitation and electrostatic laws. Somewhere you argued that $M_e/M_p$ is constant. D'accord it is as constant as the ratio of the mass of my hand versus the one of my body. But my hand is not invariant. There is no evidence that the mass of the proton is an 'absolut' invariant (irt itself). From you I expect more that nasty word : Be the first to present evidence of the invariance or to advance a physical counter-argument to the scaling model. To you it should be a piece of cake. – Helder Velez Aug 8 '11 at 18:05 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8145462274551392, "perplexity": 438.4582622470277}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461861831994.45/warc/CC-MAIN-20160428164351-00066-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://blekko.com/wiki/Integration_by_parts?source=672620ff | # Integration by parts
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In calculus, and more generally in mathematical analysis, integration by parts is a theorem that relates the integral of a product of functions to the integral of their derivative and antiderivative. It is frequently used to transform the antiderivative of a product of functions into an antiderivative for which a solution can be more easily found. The rule can be derived in one line simply by integrating the product rule of differentiation.
If u = u(x), v = v(x), and the differentials du = u '(xdx and dv = v'(xdx, then integration by parts states that
$\int u(x) v'(x) \, dx = u(x) v(x) - \int u'(x) v(x) \, dx$
or more compactly:
$\int u \, dv=uv-\int v \, du.\!$
More general formulations of integration by parts exist for the Riemann–Stieltjes integral and Lebesgue–Stieltjes integral. The discrete analogue for sequences is called summation by parts.
## Theorem
### Product of two functions
The theorem can be derived as follows. Suppose u(x) and v(x) are two continuously differentiable functions. The product rule states (in Leibniz’ notation):
$\frac{d}{dx}\left(u(x)v(x)\right) = v(x) \frac{d}{dx}\left(u(x)\right) + u(x) \frac{d}{dx}\left(v(x)\right).\!$
Integrating both sides with respect to x, over an interval axb:
$\int_a^b \frac{d}{dx}\left(u(x)v(x)\right)\,dx = \int_a^b u'(x)v(x)\,dx + \int_a^b u(x)v'(x)\,dx$
then applying the fundamental theorem of calculus,
$\int_a^b \frac{d}{dx}\left(u(x)v(x)\right)\,dx = \left[u(x)v(x)\right]_a^b$
gives the formula for integration by parts:
$\left[u(x)v(x)\right]_a^b = \int_a^b u'(x)v(x)\,dx + \int_a^b u(x)v'(x)\,dx.$
Since du and dv are differentials of a function of one variable x,
$du=u'(x)dx, \quad dv=v'(x)dx.$
The original integral ∫uv′ dx contains v′ (derivative of v); in order to apply the theorem, v (antiderivative of v′) must be found, and then the resulting integral ∫vu′ dx must be evaluated.
### Product of many functions
Integrating the product rule for three multiplied functions, u(x), v(x), w(x), gives a similar result:
$\int_a^b u v \, dw = [u v w]^{b}_{a} - \int_a^b u w \, dv - \int_a^b v w \, du.$
In general for n factors
$\frac{d}{dx} \left(\prod_{i=1}^n u_i(x) \right)= \sum_{j=1}^n \prod_{i\neq j}^n u_i(x) \frac{du_j(x)}{dx},$
which leads to
$\Bigl[ \prod_{i=1}^n u_i(x) \Bigr]_a^b = \sum_{j=1}^n \int_a^b \prod_{i\neq j}^n u_i(x) \, du_j(x),$
where the product is of all functions except for the one differentiated in the same term.
## Visualization
Graphical interpretation of the theorem. The pictured curve is parametrized by the variable t.
Define a parametric curve by (x, y) = (f(t), g(t)). Assuming that the curve is locally one-to-one, we can define
$x(y) = f(g^{-1}(y))$
$y(x) = g(f^{-1}(x))$
The area of the blue region is
$A_1=\int_{y_1}^{y_2}x(y)dy$
Similarly, the area of the red region is
$A_2=\int_{x_1}^{x_2}y(x)dx$
The total area A1 + A2 is equal to the area of the bigger rectangle, x2y2, minus the area of the smaller one, x1y1:
$\overbrace{\int_{y_1}^{y_2}x(y)dy}^{A_1}+\overbrace{\int_{x_1}^{x_2}y(x)dx}^{A_2}=\biggl.x_iy_i\biggl|_{i=1}^{i=2}$
Assuming the curve is smooth within a neighborhood, this generalizes to indefinite integrals:
$\int xdy + \int y dx = xy$
Rearranging:
$\int xdy = xy - \int y dx$
Thus integration by parts may be thought of as deriving the area of the blue region from the total area and that of the red region.
This visualisation also explains why integration by parts may help find the integral of an inverse function f−1(x) when the integral of the function f(xv) is known. Indeed, the functions x(y) and y(x) are inverses, and the integral ∫x dy may be calculated as above from knowing the integral ∫y dx.
## Application to find antiderivatives
### Strategy
Integration by parts is a heuristic rather than a purely mechanical process for solving integrals; given a single function to integrate, the typical strategy is to carefully separate it into a product of two functions u(x)v(x) such that the integral produced by the integration by parts formula is easier to evaluate than the original one. The following form is useful in illustrating the best strategy to take:
$\int uv \,dx = u \int v \,dx - \int \left ( u' \int v \,dx \right )\,dx.\!$
Note that on the right-hand side, u is differentiated and v is integrated; consequently it is useful to choose u as a function that simplifies when differentiated, and/or to choose v as a function that simplifies when integrated. As a simple example, consider:
$\int \frac{\ln x}{x^2}\,dx.\!$
Since the derivative of ln x is 1/x, we make (ln x) part of u; since the antiderivative of 1/x2 is −1/x, we make (1/x2) part of v. The formula now yields:
$\int \frac{\ln x}{x^2}\,dx = -\frac{\ln x}{x} - \int \biggl( \frac{1}{x} \biggr) \biggl( -\frac{1}{x} \biggr) \, dx.\!$
The antiderivative of −1/x2 can be found with the power rule and is 1/x.
Alternatively, we may choose u and v such that the product u' (∫v dx) simplifies due to cancellation. For example, suppose we wish to integrate:
$\int\sec^2x\ln|\sin x|dx.$
If we choose u(x) = ln |sin x| and v(x) = sec2x, then u differentiates to 1/ tan x using the chain rule and v integrates to tan x; so the formula gives:
$\int\sec^2x\ln|\sin x|dx=\tan x\ln|\sin x|-\int\tan x\frac{1}{\tan x}dx.$
The integrand simplifies to 1, so the antiderivative is x. Finding a simplifying combination frequently involves experimentation.
In some applications, it may not be necessary to ensure that the integral produced by integration by parts has a simple form; for example, in numerical analysis, it may suffice that it has small magnitude and so contributes only a small error term. Some other special techniques are demonstrated in the examples below.
Polynomials and trigonometric functions
In order to calculate
$I=\int x\cos (x) \,dx\,,$
let:
$u = x \Rightarrow d u = dx$
$dv = \cos(x)\,dx \Rightarrow v = \int\cos(x)\,dx = \sin(x)$
then:
\begin{align} \int x\cos (x) \,dx & = \int u \, dv \\ & = uv - \int v \, du \\ & = x\sin (x) - \int \sin (x) \,dx \\ & = x\sin (x) + \cos (x) + C, \end{align} \!
where C is an arbitrary constant of integration.
For higher powers of x in the form
$\int x^n e^x \,dx,\,\int x^n\sin (x) \,dx,\,\int x^n\cos (x) \,dx\,,$
repeatedly using integration by parts can evaluate integrals such as these; each application of the theorem lowers the power of x by one.
Exponentials and trigonometric functions
An example commonly used to examine the workings of integration by parts is
$I=\int e^{x} \cos (x) \,dx.$
Here, integration by parts is performed twice. First let
$u = \cos(x) \Rightarrow du = -\sin(x)\,dx$
$dv = e^x \, dx \Rightarrow v = \int e^x \,dx = e^x$
then:
$\int e^{x} \cos (x) \,dx = e^{x} \cos (x) + \int e^{x} \sin (x) \,dx.\!$
Now, to evaluate the remaining integral, we use integration by parts again, with:
$u = \sin(x) \Rightarrow du = \cos(x)\, dx$
$dv = e^x \,dx \Rightarrow v = \int e^x \,dx = e^x.$
Then:
$\int e^x \sin (x) \,dx = e^x \sin (x) - \int e^x \cos (x) \,dx.$
Putting these together,
$\int e^x \cos (x) \,dx = e^x \cos (x) + e^x \sin (x) - \int e^x \cos (x) \,dx.$
The same integral shows up on both sides of this equation. The integral can simply be added to both sides to get
$2 \int e^{x} \cos (x) \,dx = e^{x} ( \sin (x) + \cos (x) ) + C\!$
which rearranges to:
$\int e^x \cos (x) \,dx = {e^x ( \sin (x) + \cos (x) ) \over 2} + C'\!$
where again C (and C' = C/2) is an arbitrary constant of integration.
A similar method is used to find the integral of secant cubed.
Functions multiplied by unity
Two other well-known examples are when integration by parts is applied to a function expressed as a product of 1 and itself. This works if the derivative of the function is known, and the integral of this derivative times x is also known.
The first example is ∫ ln(x) dx. We write this as:
$I=\int \ln (x) \cdot 1 \,dx.\!$
Let:
$u = \ln(x) \Rightarrow du = \frac{dx}{x}$
$dv = dx \Rightarrow v = x\,$
then:
\begin{align} \int \ln (x) \,dx & = x \ln (x) - \int \frac{x}{x} \,dx \\ & = x \ln (x) - \int 1 \,dx \\ & = x \ln (x) - x + C \end{align}
where C is the constant of integration.
The second example is the inverse tangent function arctan(x):
$I=\int \arctan (x) \cdot 1 \,dx.$
Rewrite this as
$\int \arctan (x) \cdot 1 \,dx.$
Now let:
$u = \arctan(x) \Rightarrow du = \frac{dx}{1 + x^2}$
$dv =dx \Rightarrow v = x$
then
\begin{align} \int \arctan (x) \,dx & = x \arctan (x) - \int \frac{x}{1 + x^2} \,dx \\[8pt] & = x \arctan (x) - {1 \over 2} \ln \left( 1 + x^2 \right) + C \end{align}
using a combination of the inverse chain rule method and the natural logarithm integral condition.
### LIATE rule
A rule of thumb proposed by Herbert Kasube of Bradley University advises that whichever function comes first in the following list should be u:[1]
L - Logarithmic functions: ln x, logb x, etc.
I - Inverse trigonometric functions: arctan x, arcsec x, etc.
A - Algebraic functions: x2, 3x50, etc.
T - Trigonometric functions: sin x, tan x, etc.
E - Exponential functions: ex, 19x, etc.
The function which is to be dv is whichever comes last in the list: functions lower on the list have easier antiderivatives than the functions above them. The rule is sometimes written as "DETAIL" where D stands for dv.
To demonstrate the LIATE rule, consider the integral
$\int x\cos x \, dx.\!$
Following the LIATE rule, u = x and dv = cos x dx, hence du = dx and v = sin x, which makes the integral become
$x\sin x - \int 1\sin x \, dx\!$
which equals
$x\sin x + \cos x+C.\!$
In general, one tries to choose u and dv such that du is simpler than u and dv is easy to integrate. If instead cos x was chosen as u and x as dv, we would have the integral
$\frac{x^2}2\cos x + \int \frac{x^2}2\sin x\, dx,$
which, after recursive application of the integration by parts formula, would clearly result in an infinite recursion and lead nowhere.
Although a useful rule of thumb, there are exceptions to the LIATE rule. A common alternative is to consider the rules in the "ILATE" order instead. Also, in some cases, polynomial terms need to be split in non-trivial ways. For example, to integrate
$\int x^3e^{x^2}\, dx,$
one would set
$u=x^2, \quad dv=xe^{x^2}\, dx,$
so that
$du = 2x\,dx, \quad v = \frac12 e^{x^2}.$
Then
$\int x^3e^{x^2}\, dx = \int \left(x^2\right) \left( xe^{x^2} \right) \, dx = \int u \, dv = uv - \int v\,du = \frac12 x^2 e^{x^2} - \int xe^{x^2}\,dx.$
Finally, this results in
$\int x^3e^{x^2}\, dx=\frac{1}{2}e^{x^2}(x^2-1)+C.$
## Applications in pure mathematics
Integration by parts is often used as a tool to prove theorems in mathematical analysis. This section gives a few of examples.
### Use in special functions
The gamma function is an example of a special function, defined as an improper integral. Integration by parts illustrates it to be an extension of the factorial:
\begin{align} \Gamma(z) & = \int_0^\infty d\lambda e^{-\lambda} \lambda^{z-1} \\ & = - \int_0^\infty d\left(e^{-\lambda}\right) \lambda^{z-1} \\ & = - \left[e^{-\lambda}\lambda^{z-1}\right]_0^\infty + \int_0^\infty d\left(\lambda^{z-1}\right) e^{-\lambda} \\ & = 0 + \int_0^\infty d\lambda\left(z-1\right) \lambda^{z-2} e^{-\lambda} \\ & = (z-1)\Gamma(z-1) \\ \end{align}
yielding the famous identity
$\Gamma(z) = (z-1)\Gamma(z-1)\,.$
For integer z, applying this formula repeatedly gives the factorial (denoted by the !):
$\Gamma(z+1) = z!$
### Use in harmonic analysis
Integration by parts is often used in harmonic analysis, particularly Fourier analysis, to show that quickly oscillating integrals with sufficiently smooth integrands decay quickly. The most common example of this is its use in showing that the decay of function's Fourier transform depends on the smoothness of that function, as described below.
Fourier transform of derivative
If f is a k-times continuously differentiable function and all derivatives up to the kth one decay to zero at infinity, then its Fourier transform satisfies
$(\mathcal{F}f^{(k)})(\xi) = (2\pi i\xi)^k \mathcal{F}f(\xi),$
where f(k) is the kth derivative of f. (The exact constant on the right depends on the convention of the Fourier transform used.) This is proved by noting that
$\frac{d}{dy} e^{-2\pi iy\xi} = -2\pi i\xi e^{-2\pi iy\xi},$
so using integration by parts on the Fourier transform of the derivative we get
\begin{align} (\mathcal{F}f')(\xi) &= \int_{-\infty}^\infty e^{-2\pi iy\xi} f'(y)\,dy \\ &=\left[e^{-2\pi iy\xi} f(y)\right]_{-\infty}^\infty - \int_{-\infty}^\infty (-2\pi i\xi e^{-2\pi iy\xi}) f(y)\,dy \\ &=2\pi i\xi \int_{-\infty}^\infty e^{-2\pi iy\xi} f(y)\,dy \\ &=2\pi i\xi \mathcal{F}f(\xi). \end{align}
Applying this inductively gives the result for general k. A similar method can be used to find the Laplace transform of a derivative of a function.
Decay of Fourier transform
The above result tells us about the decay of the Fourier transform, since it follows that if f and f(k) are integrable then
$\vert\mathcal{F}f(\xi)\vert \leq \frac{I(f)}{1+\vert 2\pi\xi\vert^k}$, where $I(f)=\int_{-\infty}^\infty\Bigl(\vert f(y)\vert + \vert f^{(k)}(y)\vert\Bigr) dy$.
In other words, if f satisfies these conditions then its Fourier transform decays at infinity at least as quickly as 1/|ξ|k. In particular, if k ≥ 2 then the Fourier transform is integrable.
The proof uses the fact, which is immediate from the definition of the Fourier transform, that
$\vert\mathcal{F}f(\xi)\vert \leq \int_{-\infty}^\infty \vert f(y) \vert \,dy.$
Using the same idea on the equality stated at the start of this subsection gives
$\vert(2\pi i\xi)^k \mathcal{F}f(\xi)\vert \leq \int_{-\infty}^\infty \vert f^{(k)}(y) \vert \,dy.$
Summing these two inequalities and then dividing by 1 + |2πξk| gives the stated inequality.
### Use in operator theory
One use of integration by parts in operator theory is that it shows that the -∆ (where ∆ is the Laplace operator) is a positive operator on L2 (see Lp space). If f is smooth and compactly supported then, using integration by parts, we have
\begin{align} \langle -\Delta f, f \rangle_{L^2} &= -\int_{-\infty}^\infty f''(x)\overline{f(x)}\,dx \\ &=-\left[f'(x)\overline{f(x)}\right]_{-\infty}^\infty + \int_{-\infty}^\infty f'(x)\overline{f'(x)}\,dx \\ &=\int_{-\infty}^\infty \vert f'(x)\vert^2\,dx \geq 0. \end{align}
## Recursive integration by parts
Integration by parts can often be applied recursively on the ∫ v du term to provide the following formula
$\int uv = u v_1 - u' v_2 + u'' v_3 - \cdots + (-1)^{n-1}\ u^{(n-1)} \ v_{n} + (-1)^n \int{u^{(n)}v_{n}}.\!$
Here, u′ is the first derivative of u and u′′ is the second derivative. Further, u(n) is a notation to describe its nth derivative with respect to the independent variable. Another notation approved in the calculus theory has been adopted:
$v_{n+1}(x)=\int\! \int\ \cdots \int v \ (dx)^{n+1}.\!$
There are n + 1 integrals.
Note that the integrand above (uv) differs from the previous equation. The dv factor has been written as v purely for convenience.
The above mentioned form is convenient because it can be evaluated by differentiating the first term and integrating the second (with a sign reversal each time), starting out with uv1. It is very useful especially in cases when u(k + 1) becomes zero for some k + 1. Hence, the integral evaluation can stop once the u(k) term has been reached.
### Tabular integration by parts
While the aforementioned recursive definition is correct, it is often tedious to remember and implement. A much easier visual representation of this process is often taught to students and is dubbed either "the tabular method",[2] "the Stand and Deliver method",[3] "rapid repeated integration" or "the tic-tac-toe method". This method works best when one of the two functions in the product is a polynomial, that is, after differentiating it several times one obtains zero. It may also be extended to work for functions that will repeat themselves.
For example, consider the integral
$\int x^3 \cos x \, dx.\!$
Let u = x3. Begin with this function and list in a column all the subsequent derivatives until zero is reached. Secondly, begin with the function v (in this case cos(x)) and list each integral of v until the size of the column is the same as that of u. The result should appear as follows.
Derivatives of u (Column A)Integrals of v (Column B)
$x^3 \,$$\cos x \,$
$3x^2 \,$$\sin x \,$
$6x \,$$-\cos x \,$
$6 \,$$-\sin x \,$
$0 \,$$\cos x \,$
Now simply pair the 1st entry of column A with the 2nd entry of column B, the 2nd entry of column A with the 3rd entry of column B, etc... with alternating signs (beginning with the positive sign). Do so until further pairing leads to sums of zeros. The result is the following (notice the alternating signs in each term):
$(+)(x^3)(\sin x) - (3x^2)(-\cos x) + (6x)(-\sin x) - (6)(\cos x) + C \,.$
Which, with simplification, leads to the result
$x^3\sin x + 3x^2\cos x - 6x\sin x - 6\cos x + C. \,$
With proper understanding of the tabular method, it can be extended. Consider
$\int e^x \cos x \,dx.$
Derivatives of u (Column A)Integrals of v (Column B)
$e^x \,$$\cos x \,$
$e^x \,$$\sin x \,$
$e^x \,$$-\cos x \,$
In this case in the last step it is necessary to integrate the product of the two bottom cells obtaining:
$\int e^x \cos x \,dx = e^x\sin x + e^x\cos x - \int e^x \cos x \,dx,$
which leads to
$2 \, \int e^x \cos x \,dx = e^x\sin x + e^x\cos x,$
and yields the result:
$\int e^x \cos x \,dx = {e^x ( \sin x + \cos x ) \over 2} + C.\!$
## Higher dimensions
The formula for integration by parts can be extended to functions of several variables. Instead of an interval one needs to integrate over an n-dimensional set. Also, one replaces the derivative with a partial derivative.
More specifically, suppose Ω is an open bounded subset of ℝn with a piecewise smooth boundary Γ. If u and v are two continuously differentiable functions on the closure of Ω, then the formula for integration by parts is
$\int_{\Omega} \frac{\partial u}{\partial x_i} v \,d\Omega = \int_{\Gamma} u v \, \nu_i \,d\Gamma - \int_{\Omega} u \frac{\partial v}{\partial x_i} \, d\Omega,$
where $\hat{\mathbf{\nu}}$ is the outward unit surface normal to Γ, νi is its i-th component, and i ranges from 1 to n.
By replacing v in the above formula with vi and summing over i gives the vector formula
$\int_{\Omega} \nabla u \cdot \mathbf{v}\, d\Omega = \int_{\Gamma} u (\mathbf{v}\cdot \hat{\nu})\, d\Gamma - \int_\Omega u\, \nabla\cdot\mathbf{v}\, d\Omega,$
where v is a vector-valued function with components v1, ..., vn.
Setting u equal to the constant function 1 in the above formula gives the divergence theorem
$\int_{\Gamma} \mathbf{v} \cdot \hat{\nu}\, d\Gamma = \int_\Omega \nabla\cdot\mathbf{v}\, d\Omega.$
For $\mathbf{v}=\nabla v$ where $v\in C^2(\bar{\Omega})$, one gets
$\int_{\Omega} \nabla u \cdot \nabla v\, d\Omega = \int_{\Gamma} u\, \nabla v\cdot\hat{\nu}\, d\Gamma - \int_\Omega u\, \nabla^2 v\, d\Omega,$
which is the first Green's identity.
The regularity requirements of the theorem can be relaxed. For instance, the boundary Γ need only be Lipschitz continuous. In the first formula above, only u, vH1(Ω) is necessary (where H1 is a Sobolev space); the other formulas have similarly relaxed requirements.
## Notes
1. ^ Kasube, Herbert E. (1983). "A Technique for Integration by Parts". The American Mathematical Monthly 90 (3): 210–211. doi:10.2307/2975556. JSTOR 2975556.
2. ^ Khattri, Sanjay K. (2008). "FOURIER SERIES AND LAPLACE TRANSFORM THROUGH TABULAR INTEGRATION". The Teaching of Mathematics XI (2): 97–103.
3. ^ Horowitz, David (1990). "Tabular Integration by Parts". The College Mathematics Journal 21 (4): 307–311. doi:10.2307/2686368. JSTOR 2686368. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 98, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9976322054862976, "perplexity": 714.9712813938104}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-49/segments/1416400376197.4/warc/CC-MAIN-20141119123256-00225-ip-10-235-23-156.ec2.internal.warc.gz"} |
https://pos.sissa.it/326/002/ | Volume 326 - The International Conference on B-Physics at Frontier Machines (BEAUTY2018) - Session: CP violation
Theory of CP violation in B decays
K. Vos
Full text: pdf
Pre-published on: 2018 August 02
Published on: 2018 October 30
Abstract
The study of CP violation in $B$-meson decays has already reached a high level of precision, which will be pushed even higher in the future era of Belle-II and the LHCb upgrade. Here, the theoretical challenge is to control the uncertainties from strong interactions to distinguish between the Standard Model and possible New Physics effects. In this talk, I will present a selected overview of recent theoretical developments in this field. This includes, in particular, the semileptonic asymmetry $a_{\text{sl}}^s$ and extractions of the CKM angle $\gamma$ and the $B_d^0$ and $B_s^0$ mixing phases. I focus on recently proposed strategies in which the theory uncertainties can be controlled through data using flavour symmetries of the strong interaction. A newly found puzzle in the $B \to \pi K$ system is highlighted and a theoretically clean way to determine the underlying electroweak penguin parameters is discussed. Finally, the recent progress to describe three-body $B$ decays in QCD factorization is discussed.
DOI: https://doi.org/10.22323/1.326.0002
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7855072021484375, "perplexity": 1523.808813900198}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-24/segments/1590347436828.65/warc/CC-MAIN-20200604001115-20200604031115-00004.warc.gz"} |
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# If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru
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If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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25 May 2020, 04:18
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If $$0.7^{(2x^2 - 3x + 4)} < 0.343$$, then which of the following must be true?
A. x < -1/2
B. -1/2 < x < 1/2
C. 1/2 < x < 1
D. x > 1
E. x < 1/2 or x > 1
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If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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Updated on: 29 Jun 2020, 18:49
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Bunuel wrote:
If $$0.7^{(2x^2 - 3x + 4)} < 0.343$$, then which of the following must be true?
A. x < -1/2
B. -1/2 < x < 1/2
C. 1/2 < x < 1
D. x > 1
E. x < 1/2
RULE:
If $$0 < a < 1$$, then $$a^x < a^y$$ if $$x > y$$
i.e. $$0.7^{(2x^2 - 3x + 4)} < 0.343$$
i.e. $$0.7^{(2x^2 - 3x + 4)} < (0.7)^3$$
i.e. $$(2x^2 - 3x + 4) > 3$$
i.e. $$(2x^2 - 3x + 1) > 0$$
i.e. $$(2x^2 - 2x - x + 1) > 0$$
i.e. $$(2x - 1)*(x - 1) > 0$$
i.e. either both (2x - 1)*(x - 1) should be positive or both should be Negative
For both positive, x>1
For both negative, x<1/2
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Originally posted by GMATinsight on 25 May 2020, 04:34.
Last edited by GMATinsight on 29 Jun 2020, 18:49, edited 2 times in total.
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If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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Updated on: 25 May 2020, 05:32
1
Bunuel wrote:
If $$0.7^{(2x^2 - 3x + 4)} < 0.343$$, then which of the following must be true?
A. x < -1/2
B. -1/2 < x < 1/2
C. 1/2 < x < 1
D. x > 1
E. x < 1/2
Solution
• $$0.7^{(2x^2 – 3x + 4)} < 0.342$$
$$⟹0.7^{(2x^2 – 3x + 4)} < 0.7^3$$
• Since, 0.7 < 1 , so higher power of 0.7 will result in lower value.
o Therefore, $$2x^2 – 3x + 4 > 3$$
$$⟹ 2x^2 – 3x + 1 > 0$$
$$⟹ 2x^2 – 2x -x + 1> 0$$
$$⟹ 2x(x – 1) – 1(x – 1)> 0$$
$$⟹ (x – 1)(2x – 1) > 0$$
o Thus, $$x < \frac{1}{2}$$ or $$x > 1$$
Thus, the correct answer is Option E.
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Originally posted by GMATWhizTeam on 25 May 2020, 04:48.
Last edited by GMATWhizTeam on 25 May 2020, 05:32, edited 1 time in total.
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Re: If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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25 May 2020, 05:00
GMATinsight wrote:
Bunuel wrote:
If $$0.7^{(2x^2 - 3x + 4)} < 0.343$$, then which of the following must be true?
A. x < -1/2
B. -1/2 < x < 1/2
C. 1/2 < x < 1
D. x > 1
E. x < 1/2
RULE:
If $$0 < a < 1$$, then $$a^x < a^y$$ if $$y > x$$
i.e. $$0.7^{(2x^2 - 3x + 4)} < 0.343$$
i.e. $$0.7^{(2x^2 - 3x + 4)} < (0.7)^3$$
i.e. $$(2x^2 - 3x + 4) > 3$$
i.e. $$(2x^2 - 3x + 1) > 0$$
i.e. $$(2x^2 - 2x - x + 1) > 0$$
i.e. $$(2x - 1)*(x - 1) > 0$$
i.e. either both (2x - 1)*(x - 1) should be positive or both should be Negative
For both positive, x>1
For both negative, x<1/2
No match of answer... Let me check again
Bunuel I think the inequation sign should be reversed in this question. Please check.
____________________
Edited option E. Thank you.
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Re: If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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25 May 2020, 05:01
D and/or E
0.343 = 0.7^3
Also we know that :
If 0<a<1 , then for x>y a^x < a^y
==> 2x^2 -3x +4 >3
or 2x^2 - 3x +1 >0
or (2x-1)(x-1)> 0
==> X< 1/2 (Option E) or x>1 (Option D)
Am I wrong somewhere?
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If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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25 May 2020, 08:53
GMATinsight wrote:
Bunuel wrote:
If $$0.7^{(2x^2 - 3x + 4)} < 0.343$$, then which of the following must be true?
A. x < -1/2
B. -1/2 < x < 1/2
C. 1/2 < x < 1
D. x > 1
E. x < 1/2
RULE:
If $$0 < a < 1$$, then $$a^x < a^y$$ if $$y > x$$
i.e. $$0.7^{(2x^2 - 3x + 4)} < 0.343$$
i.e. $$0.7^{(2x^2 - 3x + 4)} < (0.7)^3$$
i.e. $$(2x^2 - 3x + 4) > 3$$
i.e. $$(2x^2 - 3x + 1) > 0$$
i.e. $$(2x^2 - 2x - x + 1) > 0$$
i.e. $$(2x - 1)*(x - 1) > 0$$
i.e. either both (2x - 1)*(x - 1) should be positive or both should be Negative
For both positive, x>1
For both negative, x<1/2
GMATinsight Please correct my understanding --> If $$0 < a < 1$$, then $$a^x < a^y$$ if $$y > x$$
In the above rule, Shouldn't be y>x as x>y ???
Also guide me how did the sign (<) of the original equation $$0.7^{(2x^2 - 3x + 4)} < 0.343$$ changed to (>) in the new equation $$(2x^2 - 3x + 4) > 3$$.
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Re: If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink]
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25 May 2020, 19:22
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Re: If 0.7^(2x2 - 3x + 4) < 0.343, then which of the following must be tru [#permalink] 25 May 2020, 19:22 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7968733906745911, "perplexity": 6894.799449334782}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593657147917.99/warc/CC-MAIN-20200714020904-20200714050904-00382.warc.gz"} |
https://www.hackmath.net/en/math-problem/467 | # Midpoints
Triangle whose sides are midpoints of sides of triangle ABC has a perimeter 45. How long is perimeter of triangle ABC?
Correct result:
p = 90
#### Solution:
$p=2\cdot 45=90$
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Vili ate three pieces of pie. If it pieces is 1/8 how much pie did he eat?
• Pie
Vili ate three pieces of pie . If it piece is 1/8 how much pie did he eat?
• One third 2
One third of all students in class live in a house. If here are 42 students in a class, how many of them live in house?
• A library
A library has 12,500 fiction books and 19,000 non fiction books. Currently 2/5 of the fiction books are checked out. Currently 2/5 of the non fiction books are checked out. Of the books checked out, only 1/10 are due back this week. How many books are due
• Simplify
Simplify powers multiplication: (3+22)(5-42)
• Calculate
Calculate the area of the ABE triangle AB = 38mm and height E = 42mm ps: please try a quick calculation
• The triangles
The triangles ABC and A'B'C 'are similar with a similarity coefficient of 2. The angles of the triangle ABC are alpha = 35°, beta = 48°. Determine the magnitudes of all angles of triangle A'B'C '.
• QuizQ
An isosceles triangle has two sides of length 7 km and 39 km. How long is a third side? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 1, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.575707197189331, "perplexity": 2288.1189565056584}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107878921.41/warc/CC-MAIN-20201022053410-20201022083410-00166.warc.gz"} |
https://www.physicsforums.com/threads/potentials-and-de-broglie-wavelength.150543/ | # Homework Help: Potentials and de Broglie wavelength
1. Jan 8, 2007
### Brewer
1. The problem statement, all variables and given/known data
2. Relevant equations
E=hc/λ?
and the Time Independent Schrodinger Equation.
3. The attempt at a solution
Now, would I be right in thinking for the first section that the energy for the E=hc/λ bit is just the energy of the particle given in the question (10eV).
Then for the other sections is the relevant energy just 10eV minus the potential?
As the last section will give a negative KE of the particle does that mean that it doesn't have a de Broglie wavelength? Its just a negatively decaying exponential (i.e. tending to 0)?
Does that sound like I'm on the right lines?
2. Jan 9, 2007
### Brewer
Anyone have any hints about this one? The way that I described it above is the way that I attempted it, and after using the wrong values from my data sheet (first I used k(why I picked this I don't know - maybe I just can't read!) and then $$\hbar$$ before reading the sheet properly for the value of h!) I think I have values that give decent answers.
3. Jan 9, 2007
### Dick
It sounds fine to me. Decaying exponential in the last region, yes. Is there still a question?
4. Jan 9, 2007
### Gokul43201
Staff Emeritus
Are we talking about photons or electrons? What is the general de Broglie relation for any particle? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9111815690994263, "perplexity": 1004.9098164329657}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-34/segments/1534221212910.25/warc/CC-MAIN-20180817202237-20180817222237-00371.warc.gz"} |
http://math.stackexchange.com/questions/41821/upper-bound-on-probability-of-not-choosing-certain-subsets | # Upper bound on probability of not choosing certain subsets
Given $m \geq 2$ subsets of $\{1,...,n\}$, say $A_1,...,A_m$, each of size $r$, we pick $B \subset \{1,...,n\}$ such that for any $i \in [n]$, $\displaystyle Pr\left[i \in B\right] = m^{-\frac{1}{r+1}}$, independently of the other choices. I want to show that there is a constant $\gamma_r$ (dependent only on $r$) such that
$$Pr\left[A_1\not\subseteq B \wedge ... \wedge A_m \not\subseteq B\right] \leq \gamma_r \left(1-m^{-\frac{r}{r+1}}\right)^m$$
It seems that Janson's inequality should be used here, however I can't get that to give me a constant which depends only on r. I'd appreciate any idea, and if this is at all correct.
Thanks.
Edit: I had mistakenly written that I used Azuma's inequality, however I meant Janson's.
-
You seem to ask for the probability of the event $C=[A\not\subseteq B]$, where $A$ is the union of $m$ given sets $A_k$, and $B$ is random. This is the union of the events $[i\notin B]$ for every $i\in A$. These are independent and $P(i\in B)=p$ does not depend on $i$ hence $P(C)=1-p^a$ where $a$ is the size of $A$.
In your context, $p=m^{-1/(r+1)}$ and, unless some hypothesis is missing, $a$ can be anything between $r$ and $rm$, hence the only upper bound available for every family $(A_k)$ like in your post is $$P(C)\le1-m^{-mr/(r+1)}.$$ When $m\to\infty$, the RHS converges to $1$ and the RHS of the inequality to prove converges to $0$ hence the former cannot be bounded by the latter, for any value of $\gamma_r$.
Or maybe you are asking for the probability of the event that, for every $k$, $A_k\not\subseteq B$...
Didier: Sorry, indeed the way I wrote it was misleading. I'm looking to bound $Pr\left[A_1 \not\subseteq B \wedge A_2 \not\subseteq B \wedge ... \wedge A_m \not\subseteq B\right]$. I'll fix my post. – shay May 28 '11 at 16:07 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9899120330810547, "perplexity": 88.537930966954}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-40/segments/1443737913039.71/warc/CC-MAIN-20151001221833-00002-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://cstheory.stackexchange.com/questions/42506/is-there-a-universal-gate-set-for-classical-probabilistic-computing | Is there a universal gate set for classical probabilistic computing?
We know that NAND gates are universal for deterministic classical circuits, Toffoli gates are universal for reversible deterministic classical circuits, and Clifford+T is universal for quantum circuits. However, what about classical probabilistic circuits?
It seems like if you had a "coin-flip" gate (takes no input/any input and produces 0 or 1, each with probability 1/2) and NAND, you could build any probabilistic circuit you want (up to some level of precision) with a rejection sampling procedure. The desired probabilistic circuit can be seen as a set of deterministic circuits, chosen according to some distribution; use rejection sampling to simulate that distribution and then apply the required deterministic circuit.
(by the same argument, any gate that produces a fixed, non-trivial probability distribution, plus NAND, would be universal).
Is this a question that has been looked into? Any results that I can cite?
• Not sure what you mean by a "coin-flip gate ". Could you give us the truth table for such a gate ? – William Hird Mar 11 at 15:16
• I don't know how to represent a probabilistic gate with a truth table. A "coin-flip gate" would be a 1/2 probability of an identity gate, and a 1/2 probability of a NOT gate – Sam Jaques Mar 11 at 16:15
• Well Sam, here is your chance to become famous, invent a whole new form of truth table for the gate, it will be named the " Jaques Gate" LOL – William Hird Mar 17 at 19:28 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9255308508872986, "perplexity": 1020.8330670148338}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232256980.46/warc/CC-MAIN-20190522223411-20190523005411-00333.warc.gz"} |
http://www.math.unipd.it/it/news/?id=558 | # Finite p-groups
ARGOMENTI: Seminari Dottorato
Wednesday 17 June 2009 h. 15:00, room 2AB/40
Eleonora CRESTANI (Ph.D. in Pure Math., Dip. Mat.)
"Finite p-groups"
-Abstract
A $p$-group is a group in which every element has order a power of $p$ (where $p$ is a prime). The first part of the seminar is an introduction to this area, and I will give same examples that, in particular, show why $p$-groups play such an important role in the theory of finite groups. In the second part of the seminar, some typical problems that arise in finite $p$-groups theory are presented, with a particular attention to the ones that I studied during my Ph.D.
Rif. int. C. Marastoni, T. Vargiolu, M. Dalla Riva | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7571849226951599, "perplexity": 711.6360209383384}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886106984.52/warc/CC-MAIN-20170820185216-20170820205216-00017.warc.gz"} |
http://aas.org/archives/BAAS/v31n4/dps99/259.htm | 31st Annual Meeting of the DPS, October 1999
Session 23. Edgeworth-Kuiper Belt I
Contributed Oral Parallel Session, Tuesday, October 12, 1999, 9:10-10:00am, Sala Pietro d'Abano
## [23.02] Stability of Volatiles in the Kuiper Belt and in Extra-Solar Dust Disks.
J. Stansberry, R.H. Brown, J. Lunine, D. Trilling, W. Grundy (U of Arizona)
Recent observations of a near-IR absorption feature near 2.3\mum suggest the presence of methane or higher hydrocarbons on grains (~10\mum diameter) in the circumstellar disk of 55 Cancri (Trilling and Brown (1998) Nature 395, 775). Other observations (Brown et al. (1998) Science 276, 937) suggest the presence of methane or higher hydrocarbons on the surface of the large Kuiper Belt Object 1993SC. Several processes set timescales for the persistence of volatiles in the outer reaches of a dust disk or in the Kuiper Belt: Jeans escape, energy limited escape, ballistic escape, photolysis/radiolysis, and cold-trapping. Likewise there are processes which set lifetimes for dust and surface processing under relevant conditions: radiation pressure, impacts, and fragmentation. We examine the timescales for the above processes in the context of our Kuiper Belt and the circumstellar environment of 55 Cancri and in the presence of methane and/or more carbon-rich molecules derived from it. We also examine the optical properties of grains composed of H2O, CH4, and a neutral absorber to place constraints on the abundance of methane (if that is in fact the absorber responsible for the 2.3\mum feature) in the 55 Cancri disk. Devolatilization of grains smaller than 1mm is very efficient even in the cold environment of the 55 Cancri disk. The presence of methane or its photolytic products may require sequestration in grain interiors. Conversely, on large bodies such as 1993SC cold trapping of volatiles offers ample opportunity for photolytic/radiolytic processing of methane, and probably can even stabilize methane itself over timescales comparable to the age of the Solar System. We discuss implications of these processes for nitrogen as well, although there is very little hope of detecting it in such environments on human timescales unless the Pluto--Kuiper Express mission becomes a reality. The potential for addressing issues such as these via observations with SIRTF will also be addressed. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8111760020256042, "perplexity": 4917.331402191045}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-40/segments/1443737896527.58/warc/CC-MAIN-20151001221816-00127-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://authorea.com/users/299657/articles/429144-multi-dimensional-legendre-wavelet-matrix-approach-for-hyperbolic-telegraph-equation-with-dirichlet-boundary-condition | Multi-dimensional Legendre wavelet matrix approach for hyperbolic telegraph equation with dirichlet boundary condition
• Vijay Patel,
• Dhirendra Bahuguna
Vijay Patel
Indian Institute of Technology Kanpur
Author Profile
Dhirendra Bahuguna
Indian Institute of Technology Kanpur
Author Profile
## Abstract
The present article is devoted to developing the Legendre wavelet operational matrix method (LWOMM) to find the numerical solution of two-dimensional hyperbolic telegraph equations (HTE) with appropriate initial time boundary space conditions. The Legendre wavelets series with unknown coefficients has used for approximating the solution in both of the spatial and temporal variables. The basic idea for discretizing two-dimensional HTE is based on differentiation and integration of operational matrices. By implementing LWOMM on HTE, HTE is transformed into algebraic generalized Sylvester equation. Numerical experiments are provided to illustrate the accuracy and efficiency of the presented numerical scheme. Comparisons of numerical results associated with the proposed method with some of the existing numerical methods confirm that the method is easy, accurate and fast experimentally. Moreover, we have investigated the convergence analysis of multidimensional Legendre wavelet approximation. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9065399169921875, "perplexity": 1036.9669963132733}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141191511.46/warc/CC-MAIN-20201127073750-20201127103750-00119.warc.gz"} |
https://infoscience.epfl.ch/record/219911 | Infoscience
Conference paper
# Optimal Computational Split-state Non-malleable Codes
Non-malleable codes are a generalization of classical error-correcting codes where the act of "corrupting" a codeword is replaced by a "tampering" adversary. Non-malleable codes guarantee that the message contained in the tampered codeword is either the original message m, or a completely unrelated one. In the common split-state model, the codeword consists of multiple blocks (or states) and each block is tampered with independently. The central goal in the split-state model is to construct high rate non-malleable codes against all functions with only two states (which are necessary). Following a series of long and impressive line of work, constant rate, two-state, non-malleable codes against all functions were recently achieved by Aggarwal et al. [2]. Though constant, the rate of all known constructions in the split state model is very far from optimal (even with more than two states). In this work, we consider the question of improving the rate of splitstate non-malleable codes. In the "information theoretic" setting, it is not possible to go beyond rate 1/2. We therefore focus on the standard computational setting. In this setting, each tampering function is required to be efficiently computable, and the message in the tampered codeword is required to be either the original message m or a "computationally" independent one. In this setting, assuming only the existence of one-way functions, we present a compiler which converts any poor rate, two-state, (sufficiently strong) non-malleable code into a rate-1, two-state, computational non-malleable code. These parameters are asymptotically optimal. Furthermore, for the qualitative optimality of our result, we generalize the result of Cheraghchi and Guruswami [10] to show that the existence of one-way functions is necessary to achieve rate > 1/2 for such codes. Our compiler requires a stronger form of non-malleability, called augmented non-malleability. This notion requires a stronger simulation guarantee for non-malleable codes and simplifies their modular usage in cryptographic settings where composition occurs. Unfortunately, this form of non-malleability is neither straightforward nor generally guaranteed by known results. Nevertheless, we prove this stronger form of non-malleability for the two-state construction of Aggarwal et al. [3]. This result is of independent interest. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9442670941352844, "perplexity": 842.4537639549754}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084890947.53/warc/CC-MAIN-20180122014544-20180122034544-00008.warc.gz"} |
http://fyzr.chiavette-usb-personalizzate.it/numpy-matmul-vs-dot.html | including product: dot, matmul, etc including decomposition: cholesky, svd, etc Reduction along axes sum, max, argmax, etc Sort operations implemented by Thrust sort, argsort, and lexsort Sparse matrix accelerated by cuSPARSE. , should follow standard NumPy conventions regarding shape and dtype. Inverse of an identity [I] matrix is an identity matrix [I]. The dot product gives us a very nice method for determining if two vectors are perpendicular and it will give another method for determining when two vectors are parallel. matmul(a, b) array([16, 6, 8]) numpy. Do NumPy and SciPy support Python 3. In this post, I will try to code a simple neural network problem on three different programming languages/libraries, namely TensorFlow (Python)1, Numpy (Python)2 and Wolfram Language. • tools for integrating C/C++ code. Matrix Multiplication: Inner Product, Outer Product & Systolic Array June 14, 2018 There are multiple ways to implement matrix multiplication in software and hardware. Qual é a melhor forma de fazer isso? Curto demais; Não entendeu Olhando para theano. We even saw that we can perform matrix multiplication on them. For 2D, it is equivalent to matrix multiplication. solve(a, b): Solving system of linear equations ax = b. getLocalToSceneTransform(); System. multiply(a, b) or a * b is preferred. 5 Python has a binary operator to be used for matrix multiplication: @, see PEP 465 -- A dedicated infix operator for matrix multiplication. Two-Dimensional Arrays. Matrix Multiplication Calculator Here you can perform matrix multiplication with complex numbers online for free. matrix-multiplication的标签_酷徒编程知识库 matrix-multiplication; dot-product +145 投票. sort(x) - returns a new array of x sorted in ascending order. On python 2. So Pandas is not an alternative to Numpy. After I made this change, the naïve for-loop and NumPy were about a factor of 2 apart, not enough to write a blog post about. 3 Printing Arrays When you print an array, NumPy displays it in a similar way to nested lists, but with the following layout: the last axis is printed from left to right, the second-to-last is printed from top to bottom, the rest are also printed from top to bottom, with each. In this tutorial, you will discover how to manipulate and access your data correctly in NumPy arrays. tensordot, numpy. Source Code: Github Repositories Coding simple cases on complicated frameworks often offers important insights on the prototyping abilities of our tools. 如果你想要运行教程中的示例，你至少需要在你的电脑上安装了以下一些软件:PythonNumPy这些是可能对你有帮助的:…. Therefore, the dot product of two vectors in an n-dimensional real space is the sum of the product of the vectors’ components. The number in are roughly the fluctuation of running time. sctypeNA have been. By selecting different configuration options, the tool in the PyTorch site shows you the required and the latest wheel for your host platform. Math and Architectures of Deep Learning bridges the gap between theory and practice, laying out the math of deep learning side by side with practical implementations in Python and PyTorch. Program for Dot Matrix: import numpy as np newArr = np. NumPy for Matlab Users - Page 4 of 17. cross, numpy. So, for example, C(1) = 54 is the dot product of A(:,1) with B(:,1). Python Numpy Matrix Multiplication. So Pandas is not an alternative to Numpy. matlab2python Uncategorized Leave a comment May 24, 2019 May 24, np. 先决条件 在阅读这个教程之前，你多少需要知道点Python。如果你想从新回忆下，请看看Python Tutorial. I hope you don't take this as trolling, but: What's the deal with matrix multiplication in numpy? I wanted to dot-product two vectors yesterday, and I got it right only on the third try: x. 2) Dimensions > 2, the product is treated as a stack of matrix. multiply(a, b) or a * b is preferred. In the image below, taken from Khan Academy’s excellent linear algebra course, each entry in Matrix C is the dot product of a row in matrix A and a column in matrix B [3]. Here are the running time in seconds. a @ b where a and b are 1-D or 2-D arrays). For the GPU result, Tesla K80 is a dual GPU, and this is only using one of them, which is equivalent to Tasla K40. Do NumPy and SciPy support Python 3. Users expecting this will be disappointed. Note: For dot matrix multiplication, number of column in the first matrix should be the same as the number of rows in the second matrix. inner - alternative to np. rand(N,N) M2…. python - Numpy ValueError: operands could not be broadcast together with shape python - ValueError: operands could not be broadcast together when attempting to plot a univariate distribution from a DataFrame column using Seaborn; python - ValueError: could not broadcast input array when assigning values to numpy array. The calculation. So Pandas is not an alternative to Numpy. Data Science Stack Exchange is a question and answer site for Data science professionals, Machine Learning specialists, and those interested in learning more about the field. Python Training Overview. The cipher is basically based on matrix multiplication for both encryption and decryption. array ( [np. logical_not. Ask Question Asked 2 years, 5 months ago. matmul() both are giving same results. dot function. • The numpy. Protect Your Online Data With This Highly Rated VPN for $39. sum() It will sum of all the elements in given array. import numpy as np from tinyflow. Matrix multiplication relies on dot product to multiply various combinations of rows and columns. Ecrire le code en utilisant numpy. Protect Your Online Data With This Highly Rated VPN for$39. savetxt • Data in regular column layout • Can deal with comments and different column delimiters. It provides a high-performance multidimensional array. NumPy is, just like SciPy, Scikit-Learn, Pandas, etc. Numpy code uses built-in libraries, written in Fortran over the last few decades and optimized by the authors, your CPU vendor, and you OS distributor (as well as the Numpy people) for maximal performance. sgemm() for float32 matrix-matrix multiplication and scipy. set_printoptions (precision=None, threshold=None, edgeitems=None, linewidth=None, profile=None, sci_mode=None) [source] ¶ Set options for printing. einsum() puede reducir al elemento simple más simple tf. NET Iridium, replacing both. If the second argument is 1-D, it is promoted to a matrix by appending a 1 to its dimensions. Varun December 5, 2018 Python Numpy : Select rows / columns by index from a 2D Numpy Array | Multi Dimension 2018-12-08T17:18:52+05:30 Numpy, Python No Comment In this article we will discuss how to select elements from a 2D Numpy Array. Parameters other Series. Specifically, If both a and b are 1-D arrays, it is inner product of vectors (without complex conjugation). Magnetic flux is the dot product of the magnetic field and the area vectors. mm operation to do a dot product between our first matrix and our second matrix. dot: For 2-D arrays it is equivalent to matrix multiplication, and for 1-D arrays to inner product of vectors (without complex conjugation). einsumとまあ結構たくさんあります 。 特にnumpyについてまとめますが、chainerやtensorflowで同名の API が存在する場合、numpyと同じ インターフェイス で設計されていますので. De ning an np. com Is matrix multiplication just a special case of the dot product of two sets of vectors when the sets of Stack Exchange Network Stack Exchange network consists of 176 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. dot(a1, a2): compute the dot product. dot() method. Their length corresponds to either the number of rows or the number of columns of $$\mathbf{B}$$. First, we need to install Numpy, we do this by simply running the command. eig(m): compute the eigenvalues and right eigenvectors of square matrix m. pinv , resulting in w_0 = 2. On line 38 the matrix is transposed. Rather, copy=True ensure that a copy is made, even if not strictly necessary. NumPy is also very convenient with Matrix multiplication and data reshaping. , with top). uniform(low=0. Numpy code uses built-in libraries, written in Fortran over the last few decades and optimized by the authors, your CPU vendor, and you OS distributor (as well as the Numpy people) for maximal performance. { "cells": [ { "cell_type": "markdown", "metadata": { "slideshow": { "slide_type": "slide" } }, "source": [ "# Applied Linear Algebra ", " ", "**Prerequisites**. Consider matrices A1 and A2 below. The calculation. On the other hand, cryptoanalysis is still partially hard. dot() function. With an hidden Layer that takes x as input and that use a sigmoid activation function (with parameters W and b) and an output that use a softmax function (with parameters V and c), we have :…. >>> import numpy as np. You can vote up the examples you like or vote down the ones you don't like. These are a special kind of data structure. Linear Algebra. Specifically, If both a and b are 1-D arrays, it is inner product of vectors (without complex conjugation). linalg , as detailed in section Linear algebra operations: scipy. For 2D, it is equivalent to matrix multiplication. shape[0] and col < C. So Pandas is not an alternative to Numpy. Numpy seems to be able to multiply a 1,000,000×23 matrix by its transpose in under a second, while the equivalent clojure code takes over six minutes. If both a and b are 2-D arrays, it is matrix multiplication, but using. Working with Numpy. dot() react to C- or F-contiguous arrays? The first two optimization approaches would end in different situations regarding the matrix multiplication. Suppose you have two groups of vectors: $\{a_1, \dots, a_m\}$ and \{b_1, \dots. ndarray which returns the dot product of two matrices. dot(H, V), H. dot product is the dot product of a and b. Note as well that often we will use the term orthogonal in place of perpendicular. constant([[2,1,1],[2,1,1. Numpy uses BLAS for matrix multiplication, and it is unbelievably fast. In parallel with the mathematics of vector and matrix multiplication, you will also learn fundamental programming concepts such as variables, lists, loops, functions, and libraries (NumPy). Stands for Numerical Python. Then only we can multiply matrices. Python's NumPy library also has a dedicated "matrix" type with a syntax that is a little bit closer to the MATLAB matrix: For example, the " * " operator would perform a matrix-matrix multiplication of NumPy matrices - same operator performs element-wise multiplication on NumPy arrays. MATLAB/Octave Python Description; Vector dot product: cross(a,b) Cross product: Find; conditional indexing. matrix), a vector is a 2-dimensional object-it's either a column vector (e. PEP 465 - A dedicated infix operator for matrix multiplication¶. array([2,4]) y = np. *See below for details on broadcasting in numpy. T, Y)) print(X. Each square bracket represents a row. NumPy Matrix and Linear Algebra Pandas with NumPy and Matplotlib Celluar Automata Batch gradient descent algorithm Longest Common Substring Algorithm Python Unit Test - TDD using unittest. Use of a NVIDIA GPU significantly outperformed NumPy. The cross product (written \vec{a} \times \vec{b}) has to measure a half-dozen “cross interactions”. import numpy as np import matplotlib. ones((1, 3)) B = numpy. compute >> new_points = np. mm operation to do a dot product between our first matrix and our second matrix. The mathematical paradigms that underlie deep learning typically start out as hard-to-read academic papers, often leaving engineers in the dark about how their models actually function. randomize_weights Use the numpy random class to create new starting weights, self. Question Related Numpy. Dot product/matrix multiplication: np. C++, calling the BLAS functionalities through a shared object. tensordot, não estou vendo uma maneira fácil de fazer uma multiplicação direta de matrizes em lotes. dot function. Parameters other Series. dot の挙動で直感通りの動きとならない場合がありました。よくよく調べると、与える配列の次元数ごとに異なる挙動をする仕様になっていたので、ケースごとにどうなるか調べてみました。 なお、公式ドキュメントにケースごとにどのよ. The dot product gives us a very nice method for determining if two vectors are perpendicular and it will give another method for determining when two vectors are parallel. $$\mathbf{B}$$ is a rank-2 array. 3 version of numpy (don't know about previous versions) uses >> the optimized Atlas BLAS routines for numpy. dot(a1, a2): compute the dot product. This post is a continuation of the previous post on using Python and NumPy package for linear algebra. 1) 2-D arrays, it returns normal product. A*B is matrix multiplication, so more = convenient for=20 linear algebra. Numpy dot vs matmul speed. (The @ symbol denotes matrix multiplication, which is supported by both NumPy and native Python as of PEP 465 and Python 3. norm(x) matrix or vector norm linalg. In previous articles we have looked at LU Decomposition in Python and Cholesky Decomposition in Python as two alternative matrix decomposition methods. Numpy, inserting one matrix in another matrix efficiently? 0 I am trying to make an outer product of two vectors more efficient by removing zero elements, doing the outer product and then enlarging the resulting matrix with rows of zeros or inserting into a zero matrix. Q2:torch vs numpy Numpy：NumPy系统是Python的一种开源的数值计算扩展。 这种工具可用来存储和处理大型矩阵，比Python自身的嵌套列表（nested list structure)结构要高 效的多（该结构也可以用来表示矩阵（matrix））。. Numpy code uses built-in libraries, written in Fortran over the last few decades and optimized by the authors, your CPU vendor, and you OS distributor (as well as the Numpy people) for maximal performance. mplot3d import Axes3D import matplotlib. Dot Product, Matrix Multiplication, and Hadamard Product. In parallel with the mathematics of vector and matrix multiplication, you will also learn fundamental programming concepts such as variables, lists, loops, functions, and libraries (NumPy). So Pandas is not an alternative to Numpy. An inner product is a generalization of the dot product. outer(data[key], pat_mRNA[key]). I know of cases where people didn't get multithreading in numpy w/ atlas to work. This morning I did a little test on the time difference between the two modes, direct matrix multiplication and doing the same thing with vector import time import numpy as np N=1000 M1 = np. Two-Dimensional Arrays. dot treats the columns of A and B as vectors and calculates the dot product of corresponding columns. dot product is the dot product of a and b. I would like to compute the following using numpy or scipy: Y = A ** T * Q * A. This is how the structure of the array is flattened. dot¶ DataFrame. 5 conda create -n tensorflow python=3. org - the Pandas data analysis library; matplotlib. NET Numerics is part of the Math. MKL vs OpenBlas. 2017 will forever be etched in our memories as the year Python overtook R to become the leading language for Data Science. If either a or b is 0-D (scalar), it is equivalent to multiply and using numpy. dot(y) # Yields 285 However, your problem is likely that one's a vector and one's a 2D array. 不像许多矩阵语言，NumPy中的乘法运算符=*=指示按元素计算，矩阵乘法可以使用=dot=函数或创建矩阵对象实现(参见教程中的矩阵章节) >>> A = array( [[1,1],. If V is an inner product space then it is possible to define the outer product as a linear map V → W. Currently, no builtin Python types implement the new operator, however, it can be implemented by defining __matmul__(), __rmatmul__(), and __imatmul__() for regular, reflected, and in-place matrix multiplication. ) when possible. linalg , as detailed in section Linear algebra operations: scipy. De ning an np. NumPy manual contents¶. tensordot, não estou vendo uma maneira fácil de fazer uma multiplicação direta de matrizes em lotes. For example, matrix-matrix multiplication can be time intensive for big matrices. We instead use the dot function to compute inner products of vectors, to multiply a vector by a matrix, and to multiply matrices. NumPy is a python package that can be used for Linear Algebra calculations. On line 38 the matrix is transposed. T @ Y) Notice triple loop, naively cubic complexity However, special linear algebra algorithms can do it Takeaway - Use numpy np. ix_(x, y)] - this returns data indexed by x in the first axis and by y in the second axis. Numpy code uses built-in libraries, written in Fortran over the last few decades and optimized by the authors, your CPU vendor, and you OS distributor (as well as the Numpy people) for maximal performance. dot()" method is used for. You can vote up the examples you like or vote down the ones you don't like. dot() or the built-in Python operator @ do this. Re: performance matrix multiplication vs. Create a matrix. Having only one dimension means that the vector has a length, but not an orientation (row vector vs. matmul differs from dot in two important ways: Multiplication by scalars is not allowed, use * instead. Each element of the product matrix is a dot product of a row in first matrix and a column in the second matrix. Currently I can think of two ways of how to calculate Y:. Other than the matrix multiplication discussed earlier, vectors could be multiplied by two more methods : Dot product and Hadamard Product. pi taken from open source projects. • The numpy. outer(data[key], pat_mRNA[key]). For example, a single n × n large matrix-matrix multiplication performs n 3 operations for n 2 input size, while 1024 n 3 2 × n 3 2 small matrix-matrix multiplications perform 1 0 2 4 (n 3 2) 3 = n 3 3 2 operations for the same input size. dot product is the dot product of a and b. linspace (-3, 3, N) Y = np. Fancy indexing along single axes with lists or NumPy arrays: x[:, [10, 1, 5]] Array protocols like __array__ and __array_ufunc__ Some linear algebra: svd, qr, solve, solve_triangular, lstsq … However, Dask Array does not implement the entire NumPy interface. Numpy has some gotcha features for linear algebra purists. 3 Million Jobs by 2020. To creat a vector simply surround a python list ([1,2,3]) with the np. Linear Algebra is a branch of mathematics that seeks to describe lines and planes using structures like vectors and matrices. Решение: Matmul был самым быстрым на моей машине: def get_pf_returns(weights, asset_returns): return np. matmul Matrix 타입일 경우 곱셈은 dot 연산과 동일한 결과를 생성함 188 189. dot: For 2-D arrays it is equivalent to matrix multiplication, and for 1-D arrays to inner product of vectors (without complex conjugation). Similarities. To logically negate Numpy boolean ndarrays, use np. A pertinent quote from PEP 465 - A dedicated infix operator for matrix multiplication, as mentioned by @petr-viktorin, clarifies the problem the OP was getting at: [] numpy provides two different types with different __mul__ methods. dot(X_mat)). matmul(x, y, out=None) Here,. dot - generic dot product of two arrays, np. 3) 1-D array is first promoted to a matrix, and then the product is calculated numpy. The dtype to pass to numpy. The syntax of numpy random normal. We can now do the PyTorch matrix multiplication using PyTorch’s torch. Given that most of the optimization seemed to be focused on a single matrix multiplication, let’s focus on speed in matrix multiplication. stackexchange. dot (self, other) [source] ¶ Compute the matrix multiplication between the DataFrame and other. dot(vector_a, vector_b, out = None) returns the dot product of vectors a and b. ndarray, * effectue la multiplication élémentaire, et la multiplication matricielle doit utiliser un appel de fonction ( numpy. sum() It will sum of all the elements in given array. 7 # Python 3. 先决条件 在阅读这个教程之前，你多少需要知道点Python。如果你想从新回忆下，请看看Python Tutorial. typeNA and numpy. com NumPy DataCamp Learn Python for Data Science Interactively The NumPy library is the core library for scientific computing in Python. For example, the vector v = (x, y, z) denotes a point in the 3-dimensional space where x, y, and z are all Real numbers. For 2D, it is equivalent to matrix multiplication. PEP 465 adds the @ infix operator for matrix multiplication. Sorting: np. 3) 1-D array is first promoted to a matrix, and then the product is calculated numpy. Qual é a melhor forma de fazer isso? Curto demais; Não entendeu Olhando para theano. NumPy provides a convenient and efficient way to handle the vast amount of data. Numpy Bridge¶ Converting a torch Tensor to a numpy array and vice versa is a breeze. Pre-trained models and datasets built by Google and the community. import numpy as np import matplotlib. logical_not. jit functions matmul, fast_matmul and guvectorize function matmul_gu3. Having to use the dot() function for matrix-multiply is messy -- dot(dot(A,B),C) vs. 따라서 복잡한 수학연산 등에 적합하지 않은데, Numpy는 이러한 단점을 보완하여 비교적 빠른 연산을 제공한다. matmul differs from dot in two important ways:. Check that you’re using OpenBLAS or Intel MKL. Specifically, If both a and b are 1-D arrays, it is inner product of vectors (without complex conjugation). dot() function. You may have noticed that, in some instances, array elements are displayed with a trailing dot (e. Python packaging has been a thorn. matmul, numpy. Note that copy=False does not ensure that to_numpy() is no-copy. axis may be negative, in which case it counts from the last to the first axis. The main Python package for linear algebra is the SciPy subpackage scipy. dot() with different dimensional arrays. An inner product is a generalization of the dot product. Implementing a Softmax classifier is almost similar to SVM one, except using a different loss function. As illustrated here on mathisfun Note the highlighted part is actually a dot product. Vectors in geometry are 1-dimensional arrays of numbers or functions used to operate on points on a line or plane. NumPy User Guide. The numpy docs recommend using array instead of matrix for working with matrices. on a CPU Define the Computational Graph. Items shamelessly taken from NumPy. We instead use the dot function to multiply matrices. Can someone help me ASAP?. I am trying to multiply a sparse matrix with itself using numpy and scipy. If either a or b is 0-D (scalar), it is equivalent to multiply and using numpy. 1) 2-D arrays, it returns normal product. It can also be called using self @ other in Python >= 3. For matmul: If either argument is N-D, N > 2, it is treated as a stack of matrices residing in the last two indexes and broadcast accordingly. The result is the same as the matmul () function for one-dimensional and two-dimensional arrays. Math and Architectures of Deep Learning bridges the gap between theory and practice, laying out the math of deep learning side by side with practical implementations in Python and PyTorch. Let us cover all 4 possible combinations by some test:. The era of Deep Learning and Machine Learning is at its peak. =20 Element-wise multiplication requires calling a function, multipy(A,B). GPUで、Numpy互換のAPIで行列計算ができるCupyは活発に更新されています。 sortやinv、最近はsparseまで、numpy(とscipy)の機能の多くをカバーするようになってきて、numpyの代用になりえるものになってきたと思います。 そこでどれだけの機能がサポートされているのか、そして、GPUで計算することに. Axis or axes along which a product is performed. NumPy Matrix and Linear Algebra Pandas with NumPy and Matplotlib Celluar Automata Batch gradient descent algorithm Longest Common Substring Algorithm Python Unit Test - TDD using unittest. In NumPy 1. (called numpyio actually). one of the packages that you just can’t miss when you’re learning data science, mainly because this library provides you with an array data structure that holds some benefits over Python lists, such as: being more compact, faster access in reading and writing items, being more convenient and more efficient. pinv , resulting in w_0 = 2. There are three multiplications in numpy, they are np. Kalman Filter 0 matlab 0 vscode 3 hexo 3 hexo-next 3 nodejs 3 node 3 npm 3 ros 2 caffe 16 sklearn 1 qt 5 vtk 3 pcl 4 qtcreator 1 qt5 1 network 1 mysqlcppconn 3 mysql 6 gtest 2 boost 9 datetime 3 cmake 2 singleton 1 longblob 1 poco 3 serialize 2 deserialize 2 libjpeg-turbo 2 libjpeg 2 gflags 2 glog 2 std::move 1 veloview 1 velodyne 1 vlp16 1. Consider the following example that creates and displays identical 4x3x2 arrays in R and Python:. Python, calling the BLAS functionalities through a shared object. 이 A = numpy. MKL vs OpenBlas. matmul - treating all arrays’ elements as matrices, np. dot() work differently on them. including product: dot, matmul, etc including decomposition: cholesky, svd, etc Reduction along axes sum, max, argmax, etc Sort operations implemented by Thrust sort, argsort, and lexsort Sparse matrix accelerated by cuSPARSE. Actually, most of the tiny differences comes from putting the matrix into a fitting order. outer, numpy. py') or run foo. 18) If A =[aij]is an m ×n matrix and B =[bij]is an n ×p matrix then the product of A and B is the m ×p matrix C =[cij. If both a and b are 2-D arrays, it is matrix multiplication, but using matmul or a @ b is preferred. For matmul: If either argument is N-D, N > 2, it is treated as a stack of matrices residing in the last two indexes and broadcast accordingly. Parameters other Series. It's important to know especially when you are dealing with data science or competitive programming problem. Finding the first eigenvalue can be approximated via matrix multiplication, and for sparse matrices with good spectral gap this extends to all of them. Whether to ensure that the returned value is a not a view on another array. By using NumPy, you can speed up your workflow, and interface with other packages in the Python ecosystem, like scikit-learn, that use NumPy under the hood. If the second argument is 1-D, it is promoted to a matrix by appending a 1 to its dimensions. This is something Numpy. A dense matrix stored in a NumPy array can be converted into a sparse matrix using the CSR representation by calling the csr_matrix() function. linalg implements basic linear algebra, such as solving linear systems, singular value decomposition, etc. ) Using this approach, we can estimate w_m using w_opt = Xplus @ d , where Xplus is given by the pseudo-inverse of X , which can be calculated using numpy. Linux on Android Phone The software and hardware information for Linux on Android phone is as follows: Android phone (Sony Xperia V LT25i. The advent of multicore CPUs and manycore GPUs means that mainstream processor chips are now parallel systems. Note that unlike MATLAB, * is elementwise multiplication, not matrix multiplication. 19 on conda so I decided to compile from source numpy using OpenBlas 0. Dot product of two arrays. It also works fine for getting the matrix product of a 2-D array and a 1-D array, in either direction, or two 1-D arrays. dot treats the columns of A and B as vectors and calculates the dot product of corresponding columns. , int, float, etc. dot() method Create two 200 \times 200 matrices in Python and fill them with random values using np. sum(x, axis= return x # get the mnist dataset mnist. (The @ symbol denotes matrix multiplication, which is supported by both NumPy and native Python as of PEP 465 and Python 3. array as da from multiprocessing import cpu_count n = 10**8 a = np. tensordot, numpy. The matrix multiplication of A and B is calculated as follows: The matrix operation is performed by using the built-in dot function available in NumPy as follows: Initialize the arrays: x=np. Your comments Summary. By the way, it is useless to combine Psyco and NumPy. We can think of a 1D NumPy array as a list of numbers. NumPy for Matlab Users - Page 4 of 17. Specifically, If both a and b are 1-D arrays, it is inner product of vectors (without complex conjugation). Re: performance matrix multiplication vs. numpy矢量法计算行积积积矩阵. Indexing: data[np. All of the NumPy array methods for operating on arrays Some very basic linear algebra support (determinant, matrix hat operator, inverse, least squares, SVD, matrix power, and multi-dot product). It's not surprise, really, that performance differs. Similarities. matlab2python Uncategorized Leave a comment May 24, 2019 May 24, np. The @ sign can now be used on types implementing the __matmul__ special/magic/dunder method. 如果两个参数a,ba,ba,b都是222维的，该运算做矩阵乘法，但是使用matmul或者[email protected]更好np. Since then, I've written and personally released. 就像 Tensorflow 当中的 tensor 一样. matmul() function returns the matrix product of two arrays. Matrix multiplication is where two matrices are multiplied directly. print("A * B = ", np. That means you can take the dot product of $$a$$ with itself, without transposing the second argument. numpy arrays are not matrices, and the standard operations *, +, -, / work element-wise on arrays. This morning I did a little test on the time difference between the two modes, direct matrix multiplication and doing the same thing with vector import time import numpy as np N=1000 M1 = np. A vector in NumPy is basically just a 1-dimensional array. GPUで、Numpy互換のAPIで行列計算ができるCupyは活発に更新されています。 sortやinv、最近はsparseまで、numpy(とscipy)の機能の多くをカバーするようになってきて、numpyの代用になりえるものになってきたと思います。 そこでどれだけの機能がサポートされているのか、そして、GPUで計算することに. 5 and above, the matrix multiplication operator from PEP 465 (i. The calculation. Matrix Multiplication: Inner Product, Outer Product & Systolic Array June 14, 2018 There are multiple ways to implement matrix multiplication in software and hardware. This lesson is a very good starting point if you are getting started into Data Science and need some introductory mathematical overview of these components and how we can play with them using NumPy in code. It provides a high-performance multidimensional array. dot can be used to multiply a list of vectors by a matrix but the orientation of the vectors must be vertical so that a list of eight two component vectors appears like two eight components vectors:. 이 A = numpy. 5 Python has a binary operator to be used for matrix multiplication: @, see PEP 465 -- A dedicated infix operator for matrix multiplication. compute >> new_points = np. In other words, any value within the given interval is equally likely to be drawn by uniform. After I made this change, the naïve for-loop and NumPy were about a factor of 2 apart, not enough to write a blog post about. dot(H, V), H. The syntax of numpy random normal. ones((2,4)) print a*b. It can handle 2D arrays but considering them as matrix and will perform matrix multiplication. However, it is not guaranteed to be compiled using efficient routines, and thus we recommend the use of scipy. Syntax numpy. Takeaway - Use numpy np. matmul (vector1, matrix1) np. In this tutorial, we will use some examples to disucss the differences among them for python beginners, you can learn how to use them correctly by this tutorial. Taking pandas aside for now, numpy already offers a bunch of functions that can do quite the same. The challenge is to develop application software that transparently scales its parallelism to leverage the increasing number of processor cores, much as 3D graphics applications transparently scale their parallelism to manycore GPUs with widely varying numbers of cores. Magnetic flux is the dot product of the magnetic field and the area vectors. dot (A, B). matrix, and * will be treated like matrix multiplication. As you saw in the last section, MATLAB insists that the dimensions of arrays align when performing matrix multiplication, while NumPy is a little bit more flexible. Nel capitolo precedente abbiamo visto come fare le moltiplicazioni tra matrici utilizzando il pacchetto numpy per python. inner, numpy. The dot product is also a scalar in this sense, given by the formula, independent of the coordinate system. 5 Python has a binary operator to be used for matrix multiplication: @, see PEP 465 -- A dedicated infix operator for matrix multiplication. The size of matrix is 128x256. Fancy indexing along single axes with lists or NumPy arrays: x[:, [10, 1, 5]] Array protocols like __array__ and __array_ufunc__ Some linear algebra: svd, qr, solve, solve_triangular, lstsq … However, Dask Array does not implement the entire NumPy interface. matrix objets, * effectue la multiplication matricielle, et la multiplication élémentaire nécessite la syntaxe de la fonction. Matrix Multiplication. According to my experiment, even after compiling optimization (-O2 with loop unrolling), the generic C code is still ~30 times slower than numpy for a. 4 conda create -n tensorflow python=3. It is important to note that whilst this feature shipped in 3. NumPy manual contents¶. dot taken from open source projects. matmul (True) or for-loop with numpy. A*B is matrix multiplication, so more = convenient for=20 linear algebra. assert_warns can now be used as a context manager ¶. However, unlike octave (which I was using till recently), * doesn't perform matrix multiplication, you need to use the function matrixmultipy(). The examples here can be easily accessed from Python using the Numpy_Example_Fetcher. A mxn x B pxq then n should be equal to p. 4: matmul() It is used to calculate the matrix multiplication of two arrays. 그러나 in Python 3. array([[10, 10], [20, 20]]) Perform the matrix multiplication using the dot function in the numpy package:. Some key differences. If both a and b are 2-D arrays, it is matrix multiplication, but using matmul or a @ b is preferred. dot is available both as a function in the numpy module and as an instance method of array objects:. matmul(vector1, matrix1) np. dot: For 2-D arrays it is equivalent to matrix multiplication, and for 1-D arrays to inner product of vectors (without complex conjugation). einsum() puede reducir al elemento simple más simple tf. The cipher is basically based on matrix multiplication for both encryption and decryption. astype(int. dot() with different dimensional arrays. The matrix multiplication of A and B is calculated as follows: The matrix operation is performed by using the built-in dot function available in NumPy as follows: Initialize the arrays: x=np. 765 s CUDA with shared memory : 0. rand() # Compare 200x200 matrix-matrix multiplication speed import numpy as np # Set up the variables A = None B = None. Then we are going to see the computation between two arrays. Here is how it works. Similarities. dot(batch xs, def softmax(x) : np. Numpy Few people make this comparison, but TensorFlow and Numpy are quite similar. dot(b) for matrix multiplication here is the code:. 03175853, 1. dot の挙動で直感通りの動きとならない場合がありました。よくよく調べると、与える配列の次元数ごとに異なる挙動をする仕様になっていたので、ケースごとにどうなるか調べてみました。 なお、公式ドキュメントにケースごとにどのよ. vdot, numpy. Pre-trained models and datasets built by Google and the community. matmul张量矩阵乘法（形状必须是2级，但是等级3的错误） python numpy tensorflow matrix-multiplication tensor 110. dot - generic dot product of two arrays, np. NumPy Datatypes. It has Native Windows Support. You don’t need any special packages to create Scalar, since it’s just a number. Nel capitolo precedente abbiamo visto come fare le moltiplicazioni tra matrici utilizzando il pacchetto numpy per python. In addition, the Cooley-Tukey algorithm can be extended to use splits of size other than 2 (what we've implemented here is known as the radix-2 Cooley-Tukey FFT). This is due to a difference in the data-type used: This is due to a difference in the data-type used:. Python has been one of the premier, flexible, and powerful open-source language that is easy to learn, easy to use, and has powerful libraries for data manipulation and analysis. , [5 x 1]) or a row vector (e. For 1-D arrays, it is the inner product of the vectors. Dot Product and Matrix Multiplication DEF(→p. matmul differs from dot in two important ways: Multiplication by scalars is not allowed, use * instead. assert_warns can now be used as a context manager ¶. The era of Deep Learning and Machine Learning is at its peak. constant([[1,2,3],[1,2,3],[1,2,3]]) y=tf. multiply(a, b) or a * b. For 2D, it is equivalent to matrix multiplication. In this Python tutorial, we will learn how to perform multiplication of two matrices in Python using NumPy. Matrix multiplication for 2D arrays. Python execution times for matrix multiplication. The implementation of matmul function has also been changed and uses the same BLAS routines as numpy. dot function. Learn Python - Python tutorial - python matrix - Python examples - Python programs Transpose of a matrix is a task we all can perform very easily in python (Using a nested loop). dot(X_mat)). dot is deprecated, as are all the other numpy names that had been copied to the scipy namespace. We even saw that we can perform matrix multiplication on them. Fancy indexing along single axes with lists or NumPy arrays: x[:, [10, 1, 5]] Array protocols like __array__ and __array_ufunc__ Some linear algebra: svd, qr, solve, solve_triangular, lstsq … However, Dask Array does not implement the entire NumPy interface. What is NumPy? Installing NumPy; Quickstart tutorial. Почему numpy не делает это умножение? Когда я пытаюсь выполнить следующий код, я получаю сообщение об ошибке: ValueError: operands could not be broadcast together with shapes (3,2) (2,4) a = np. shape[1]: tmp = 0. Ask Question Asked 2 years, 5 months ago. For 2-D vectors, it is the equivalent to matrix multiplication. mplot3d import Axes3D # Our 2-dimensional distribution will be over variables X and Y N = 60 X = np. NumPy for Matlab Users - Page 4 of 17. If either a or b is 0-D (scalar), it is equivalent to multiply and using numpy. in a single step. The operator module also defines a few predicates to test the type of objects; however, these are not all reliable. Fredholm1 operator. We instead use the dot function to compute inner products of vectors, to multiply a vector by a matrix, and to multiply matrices. NET initiative and is the result of merging dnAnalytics with Math. Numpy dot() Matrix Multiplication: As NumPy is famous for the support of Mathematic tools, so to perform matrix multiplication we do not need to write an algorithm NumPy provides users with an inbuilt dot() method which can multiply two matrices. matmul() both are giving same results. NET Iridium, replacing both. So, sometimes it is not easy to vectorize everything, especially when I have to maintain a high dimension matrix. Numpy dot() Matrix Multiplication: As NumPy is famous for the support of Mathematic tools, so to perform matrix multiplication we do not need to write an algorithm NumPy provides users with an inbuilt dot() method which can multiply two matrices. compute >> new_points = np. Each value is a Python objects with extra memory overhead. 5 Only the CPU version of TensorFlow is available at the moment and can be installed in the conda environment for Python 2 or Python 3. Numpy allows two ways for matrix multiplication: the matmul function and the @ operator. more personal to me than you might think. A Softmax classifier optimizes a cross-entropy loss that has the form: where. However, for speed, numeric types are automatically converted to native hardware types (i. typeNA and numpy. one of the packages that you just can’t miss when you’re learning data science, mainly because this library provides you with an array data structure that holds some benefits over Python lists, such as: being more compact, faster access in reading and writing items, being more convenient and more efficient. If V is an inner product space then it is possible to define the outer product as a linear map V → W. The constant we add at the end is called a bias value, and an alternative way to notate it is to add an input node for it that always has a value of 1 for the input and -18 for the edge. Torch 自称为神经网络界的 Numpy, 因为他能将 torch 产生的 tensor 放在 GPU 中加速运算 (前提是你有合适的 GPU), 就像 Numpy 会把 array 放在 CPU 中加速运算. Numpy Few people make this comparison, but TensorFlow and Numpy are quite similar. inv(m): compute the inverse of matrix m; numpy. Q So how do we create a vector in Python? A We use the ndarray class in the numpy package. linalg , as detailed in section Linear algebra operations: scipy. multiply(),np. dot: For 2-D arrays it is equivalent to matrix multiplication, and for 1-D arrays to inner product of vectors (without complex conjugation). jit def matmul(A, B, C): """Perform matrix multiplication of C = A * B """ row, col = cuda. Classification Algorithms¶. matmul(a, b) array([16, 6, 8]) numpy. Deprecated: Function create_function() is deprecated in /home/chesap19/public_html/hendersonillustration. 2017 will forever be etched in our memories as the year Python overtook R to become the leading language for Data Science. 5+ matrix multiplication @ (2) I recently moved to Python 3. dot_prod_total = sum(np. TensorFlow vs. , the complex conjugate of 5+3j is 5-3j and similarly, the complex conjugate of 2-5j is 2+5j. savetxt • Data in regular column layout • Can deal with comments and different column delimiters. inner fonctionne de la même manière que numpy. dot(vector_a, vector_b, out = None) returns the dot product of vectors a and b. opencv and numpy matrix multiplication vs element-wise multiplication Guide opencv. tensordot - the most generic (generialized to tensors) dot product. multiply(a, b) or a * b. After matrix multiplication the prepended 1 is removed. ブロードキャストしたNumpy配列に代入するときにハマった話; tf. Ecrire le code en utilisant numpy. Contents of the Numpy Array : [[0 0 0 0 0 0] [0 0 0 0 0 0] [0 0 0 0 0 0] [0 0 0 0 0 0] [0 0 0 0 0 0]] It will create a 2D numpy array of ints filled with zeros. matmul(vector1, matrix1) np. Using NumPy is by far the easiest and fastest option. linalg module has many matrix/vector manipulation algorithms (a subset of these is in the table) 10 Numpy: Linear Algebra name explanation dot(a,b) dot product of two arrays kron(a,b) Kronecker product linalg. matrix_power matrix_power는 정방행렬에 대해 dot 연산을 제곱승만큼 계산하는 것 190 191. Samples are uniformly distributed over the half-open interval [low, high) (includes low, but excludes high). multiply (a, b) or a * b is preferred. Vectors in geometry are 1-dimensional arrays of numbers or functions used to operate on points on a line or plane. As illustrated here on mathisfun Note the highlighted part is actually a dot product. Then only we can multiply matrices. NumPy is a commonly used Python data analysis package. For the GPU result, Tesla K80 is a dual GPU, and this is only using one of them, which is equivalent to Tasla K40. multiply(a, b) or a * b. Comparing two equal-sized numpy arrays results in a new array with boolean values. Built-In Data Structures. To creat a vector simply surround a python list ([1,2,3]) with the np. Matrix Multiplication: Inner Product, Outer Product & Systolic Array June 14, 2018 There are multiple ways to implement matrix multiplication in software and hardware. dot() function. In this post, I will try to code a simple neural network problem on three different programming languages/libraries, namely TensorFlow (Python)1, Numpy (Python)2 and Wolfram Language. T) for shape (-1, 4) row vectors (“array of points”). Topics of Today •linear algebra concepts, such as vectors, or dot products •Python library numpy, most important functions •differential calculus concepts, such as. opencv and numpy matrix multiplication vs element-wise multiplication. Use the “inv” method of numpy’s linalg module to calculate inverse of a Matrix. Linear Algebra. tensordot - the most generic (generialized to tensors) dot product. The '*' operator and numpy. NumPy manual contents¶. This is principially all right, because they behave in most aspects like our mathematical idea of a matrix. Setting up. For matmul: If either argument is N-D, N > 2, it is treated as a stack of matrices residing in the last two indexes and broadcast accordingly. Learn Python - Python tutorial - python matrix - Python examples - Python programs Transpose of a matrix is a task we all can perform very easily in python (Using a nested loop). Examples include: Mechanical work is the dot product of force and displacement vectors, Power is the dot product of force and velocity. Pandas is built on top of NumPy. Matrix multiplication is not commutative. dot(a, b, out=None)两个numpy数组的点乘(1). Python 2 vs Python 3¶. In [14]: # Numpy matrix multiplication print(np. com NumPy DataCamp Learn Python for Data Science Interactively The NumPy library is the core library for scientific computing in Python. Net Standard 2. dot() react to C- or F-contiguous arrays? The first two optimization approaches would end in different situations regarding the matrix multiplication. If both a and b are 2-D arrays, it is matrix multiplication, but using matmul or a @ b is preferred. 如果两个参数a,ba,ba,b都是222维的，该运算做矩阵乘法，但是使用matmul或者[email protected]更好np. 3 Million Jobs by 2020. array([[1, 1], [2, 2]]) y=np. (Both are N-d array libraries!) Numpy has Ndarray support, but doesn't offer methods to create tensor functions and automatically compute derivatives (+ no GPU support). Parameters. A vector in NumPy is basically just a 1-dimensional array. logical_not. (The @ symbol denotes matrix multiplication, which is supported by both NumPy and native Python as of PEP 465 and Python 3. Note that copy=False does not ensure that to_numpy() is no-copy. 5 and noticed the new matrix multiplication operator (@) sometimes behaves differently from the numpy dot operator. jit def matmul(A, B, C): """Perform matrix multiplication of C = A * B """ row, col = cuda. To use Numpy in our project we need to import it. The product C of two matrices A and B is defined as c_(ik)=a_(ij)b_(jk), (1) where j is summed over for all possible values of i and k and the notation above uses the Einstein summation convention. Numpy arrays are a very good substitute for python lists. This is an introductory guide to ndarray for people with experience using NumPy, although it may also be useful to others. Available for free under the MIT/X11 License. Replace numpy. • NumPyの速度にどこまで近づけるか？. Python is a general-purpose interpreted, interactive, object-oriented, and high-level programming language. For the GPU result, Tesla K80 is a dual GPU, and this is only using one of them, which is equivalent to Tasla K40. matmul(x,y). You can use these arithmetic operations to perform numeric computations, for example, adding two numbers, raising the elements of an array to a given power, or multiplying two matrices. For 1D, it is the inner product. Notably, Dask Array lacks the following. The code is based on system Embedded systems used in real-time applications require low power, less area and high computation speed. dot(a, b, out=None)两个numpy数组的点乘(1). from __future__ import division from numba import cuda import numpy import math # CUDA kernel @cuda. matmul(C, np. 3 Million Jobs by 2020. If either a or b is 0-D (scalar), it is equivalent to multiply and using numpy. Let's find the dot product without using the NumPy library. Using NumPy is by far the easiest and fastest option. dot (A, B). Ask Question Asked 1 year, 8 months ago. Pour les objets numpy. sgemm() for float32 matrix-matrix multiplication and scipy. Suppose you have two groups of vectors: [math]\{a_1, \dots, a_m\} and [math]\{b_1, \dots. 9978 and w_1 = 2. In this article, we will be learning how we can perform basic mathematical operations using Numpy. While Python is a robust general-purpose programming language, its libraries targeted towards numerical computation will win out any day when it comes to large batch operations on arrays. NET initiative and is the result of merging dnAnalytics with Math. Torch 自称为神经网络界的 Numpy, 因为他能将 torch 产生的 tensor 放在 GPU 中加速运算 (前提是你有合适的 GPU), 就像 Numpy 会把 array 放在 CPU 中加速运算. Speed increases can be obtained relatively easily with faster CPUs and more memory. uniform numpy. We even saw that we can perform matrix multiplication on them. (Both are N-d array libraries!) Numpy has Ndarray support, but doesn't offer methods to create tensor functions and automatically compute derivatives (+ no GPU support).
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https://worldwidescience.org/topicpages/m/modeling+gypsum+plaster.html | #### Sample records for modeling gypsum plaster
1. PPF-reinforced, ESP-lightened gypsum plaster
Directory of Open Access Journals (Sweden)
García Santos, A.
2009-03-01
2. Estimates of the radiation dose from phospho-gypsum plaster-board if used in domestic buildings
International Nuclear Information System (INIS)
O'Brien, R.S.; Peggie, J.R.; Leith, I.S.
1991-02-01
This report presents the results of a study carried out to estimate the annual effective dose equivalent contribution from phospho-gypsum plaster-board if it were used as an internal lining in buildings. The study considered four sources of radiation exposure that would arise in such use, such as inhalation of 222 Rn and its daughters, inhalation of phospho-gypsum dust and exposure to beta and gamma radiation. Measurements of the 22 6Ra content and 222 Rn exhalation rate were made for a number of samples of phospho-gypsum plaster-board, and the behaviour of 222 Rn and its daughters in a typical building was modelled. The results of the study suggest that, for building ventilation rates greater than approximately 0.5 air changes per hour, the contribution to the total annual effective dose equivalent from inhalation of radon ( 222 Rn) and its daughters ( 218 Po, 214 Pb, 214 Po) exhaled from the phospho-gypsum plaster-board should be well below the recommended limit of 1 milli-Sievert for members of the public. The total annual effective dose equivalent from all these sources should be less than 0.6 milli-Sieverts, provided reasonable work practices are observed during installation of the phospho-gypsum plaster-board and the ventilation rate is kept above approximately 0.5 air changes per hour. 31 refs., 12 tabs., 5 figs
3. Luminescence rigidochromism as a probe for the setting of gypsum plaster
International Nuclear Information System (INIS)
Kunkely, Horst; Vogler, Arnd
2008-01-01
The setting of gypsum plaster can be monitored by luminescence rigidochromism. The progress of the setting process which is accompanied by hardening is indicated by a blue shift of the phosphorescence of a suitable water soluble rhenium complex. This rigidity increase of the plaster/water mixture takes place in two phases. In the beginning the rigidity increase is rather large while in the second much longer phase it is relatively small. The addition of a plasticizer (or retarder) keeps the rigidity smaller in the beginning, but only slightly affects the final rigidity of the set plaster
4. Populations of some molds in water-damaged homes may differ if the home was constructed with gypsum drywall compared to plaster
Science.gov (United States)
Starting in the 1940s, gypsum drywall began replacing plaster and lathe in the U.S. home construction industry. Our goal was to evaluate whether some mold populations differ in water- damaged homes primarily constructed with gypsum drywall compared to plaster. The dust samples fr...
5. Suitability of Gypsum for the Production of Gypsum Plaster an Example from the Abu-Ruweis Evaporites (Upper Triassic), as Subayhi Area, Northwest Jordan
International Nuclear Information System (INIS)
Saqqa, W.; Arikat, M.
2003-01-01
The gypsum of Abu Ruweis Formation (Upper Triassic) of the northwestern Jordan was chemically, physically and mechanically assessed for likely industrial uses. Chemical results indicate that the investigated gypsum (calcium sulfate dihydrate) is highly pure. This is confirmed by the high ratios of CaO (32-33%) andSO 3 (41-43%) and the very low content of other elements such as Mg, Al and Si. Trace elements are also negligible. The CaSO 4 % (86-88%), purity ratio (CaO/SO 3 ) (0.85) , and combined water (≅5%) for β-hemihydrate gypsum agree well with the jordanian standards for gypsum plaster. Thermal analyses indicate that the temperature required to obtain hemihydrate gypsum falls between 175deg-200deg. A significant mass variation or maximum loss on weight (-20%) was achieved after initial dehydration by heating to 200deg. Heating to 225deg is far enough to evolve all combined water molecules. The results of fineness, consistency, setting time, compressive strength and flexural strength for β-hemilhydrate agree, in most of the case, with the local and international standards intended for gypsum building components. The study showed that the absorption and consistency ratios for final gypsum product are proportional to porosity, whilst the consistency itself decreases with the increase of applied stresses. (author)
6. Effect of different forms of silica on the physical and mechanical properties of gypsum plaster composites
Directory of Open Access Journals (Sweden)
Khalil, A. A.
2013-12-01
7. Dimensional changes in plaster cast models due to the position of the impression tray during setting
Directory of Open Access Journals (Sweden)
Betina Grehs Porto
2014-01-01
Full Text Available Introduction: The objective of this study was to assess whether the positioning of the impression tray could cause distortion to plaster casts during gypsum setting time.Materials and Methods: Fifteen pairs of master models were cast with alginate impression material and immediately filled with gypsum. Impressions were allowed to set with the tray in the noninverted position (Group A or in the inverted position (Group B. The plaster models were digitized using a laser scanner (3Shape R-700, 3Shape A/S, Copenhagen, Denmark. Measurements of tooth size and distance were obtained using O3d software (Widialabs, Brazil measurement tools. Data were analyzed by paired t-test and linear regression with 5% significance.Results and Conclusion: Most of the measurements from both groups were similar, except forthe lower intermolar distance. It was not possible to corroborate the presence of distortions due to the position of the impression tray during gypsum setting time.
8. The Potential Ability of Plaster to Cause Breast Cancer as Indicated by CA15-3 and CEA Antigens in Women Working in Gypsum Factory
Directory of Open Access Journals (Sweden)
Ali Abdul Hussein S. AL-Janabi
2017-07-01
Full Text Available Plaster is an important form of gypsum that mainly used in building construction. Breast cancer was investigated among women exposure to the dust of such material. The levels of CA15-3 and carcinoembryonic antigens (CEA as indicators for breast cancer were measured in the serum of 120 women working in a plaster factory. All of involved women showed a normal level of CEA, while 12.5% of them had moderately elevated levels of CA15-3. In conclusion; plaster dust has no significant effect to cause breast cancer in working women. Moderately high levels of CA15-3 in some of exposed women may relate to liver diseases. Key words: Breast Cancer, Plaster, CA15-3, CEA
9. Development of materials that cover the deposits of gypsum exploited in the polo plasterer in Pernambuco
International Nuclear Information System (INIS)
Rego, S.A.B.C.; Moraes, A.S. de; Anjos, I.F. dos; Lira, B.B.
2012-01-01
The mineral clay found on the surface of gypsum deposits in the region of Recife - PE are considered mining tailings and job search reference in new industrial applications for these minerals, ores. In this context, we performed the characterization of these materials with the purpose of its use as inorganic pigments in the ceramic coating. These minerals present 'in locus' different colors ranging from beige to reddish. After heat treatment at 1000° C their colors have varied tones that can be used as natural pigments in the ceramic industry. The techniques of fluorescence X-ray diffraction X-ray, infrared and colorimetry were applied in the characterization of mineral-ore in question. Using mineral processing techniques we obtain a physical separation of clay minerals associated. The use of concentrated after processing showed that the material has the potential to replace traditional pigments used in ceramic industry, and thus represent a new alternative on the market of natural pigments. Another potential comprehensive analysis of the material is its use associated with polymers in order to develop new materials. (author)
10. Comparison of the surface roughness of gypsum models constructed using various impression materials and gypsum products
Directory of Open Access Journals (Sweden)
Yi-Chih Chang
2016-03-01
Conclusion: The surface roughness of stone models was mainly determined by the type of alginate impression material, and was less affected by the type of silicone rubber impression material or gypsum product, or the storage time before repouring.
11. [The effect of disinfectant soaking on dental gypsum model size].
Science.gov (United States)
Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan
2012-12-01
To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.
12. Comparison of linear measurements and analyses taken from plaster models and three-dimensional images.
Science.gov (United States)
Porto, Betina Grehs; Porto, Thiago Soares; Silva, Monica Barros; Grehs, Renésio Armindo; Pinto, Ary dos Santos; Bhandi, Shilpa H; Tonetto, Mateus Rodrigues; Bandéca, Matheus Coelho; dos Santos-Pinto, Lourdes Aparecida Martins
2014-11-01
Digital models are an alternative for carrying out analyses and devising treatment plans in orthodontics. The objective of this study was to evaluate the accuracy and the reproducibility of measurements of tooth sizes, interdental distances and analyses of occlusion using plaster models and their digital images. Thirty pairs of plaster models were chosen at random, and the digital images of each plaster model were obtained using a laser scanner (3Shape R-700, 3Shape A/S). With the plaster models, the measurements were taken using a caliper (Mitutoyo Digimatic(®), Mitutoyo (UK) Ltd) and the MicroScribe (MS) 3DX (Immersion, San Jose, Calif). For the digital images, the measurement tools used were those from the O3d software (Widialabs, Brazil). The data obtained were compared statistically using the Dahlberg formula, analysis of variance and the Tukey test (p < 0.05). The majority of the measurements, obtained using the caliper and O3d were identical, and both were significantly different from those obtained using the MS. Intra-examiner agreement was lowest when using the MS. The results demonstrated that the accuracy and reproducibility of the tooth measurements and analyses from the plaster models using the caliper and from the digital models using O3d software were identical.
13. Gypsum Formation during the Messinian Salinity Crisis: an Alternative Model
Science.gov (United States)
Grothe, A.; Krijgsman, W.; Sangiorgi, F.; Vasiliev, I.; Baak, C. V.; Wolthers, M.; Stoica, M.; Reichart, G. J.; Davies, G.
2016-12-01
During the Messinian Salinity Crisis (MSC; 5.97 - 5.33 Myr ago), thick packages of evaporites (gypsum and halite) were deposited in the Mediterranean Basin. Traditionally, the occurrence of these evaporites is explained by the so-called "desiccation-model", in which evaporites are considered to result from a (partly) desiccated basin. In the last decade, it was thought that changes in the Mediterranean-Atlantic connectivity could explain the formation of gypsum. Stable isotope studies, however, show that the gypsum formed under influence of large freshwater input. Here we present new strontium isotope data from two well-dated Messinian sections in the Black and Caspian Seas. Our Sr isotope records suggest a persistent Mediterranean-Black Sea connection throughout the salinity crisis, which implies a large additional freshwater source to the Mediterranean. We claim that low saline waters from the Black Sea region are a prerequisite for gypsum formation in the Mediterranean and speculate about the mechanisms explaining this apparent paradox.
14. Housing: plastered versus un-plastered brooder walls in poultry ...
African Journals Online (AJOL)
An investigation was carried out to study the health impact of inadequate brooder house with poor make-up on chicks. Two brooder houses were constructed with a mixture of sand and cementitious materials consisting of lime and/or gypsum to form concrete blocks. Brooder 1 was plastered with cement (cemented) and ...
15. Delamination of plasters applied to historical masonry walls: analysis by acoustic emission technique and numerical model
Science.gov (United States)
Grazzini, A.; Lacidogna, G.; Valente, S.; Accornero, F.
2018-06-01
Masonry walls of historical buildings are subject to rising damp effects due to capillary or rain infiltrations, which in the time produce decay and delamination of historical plasters. In the restoration of masonry buildings, the plaster detachment frequently occurs because of mechanical incompatibility in repair mortar. An innovative laboratory procedure is described for test mechanical adhesion of new repair mortars. Compression static tests were carried out on composite specimens stone block-repair mortar, which specific geometry can test the de-bonding process of mortar in adherence with a stone masonry structure. The acoustic emission (AE) technique was employed for estimating the amount of energy released from fracture propagation in adherence surface between mortar and stone. A numerical simulation was elaborated based on the cohesive crack model. The evolution of detachment process of mortar in a coupled stone brick-mortar system was analysed by triangulation of AE signals, which can improve the numerical model and predict the type of failure in the adhesion surface of repair plaster. Through the cohesive crack model, it was possible to interpret theoretically the de-bonding phenomena occurring at the interface between stone block and mortar. Therefore, the mechanical behaviour of the interface is characterized.
16. Technical economical study of plaster production in a continuous rotate kiln using natural gas; Estudo tecnico-economico do processo de producao de gesso em forno rotativo continuo com uso de gas natural
Energy Technology Data Exchange (ETDEWEB)
Benachour, M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Santos, Valdemir A. dos [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil); Peres, Luciano dos S. [Instituto de Tecnologia de Pernambuco (ITEP), Recife, PE (Brazil); Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Zimmerle, Sergio R.T.S. [Companhia Pernambucana de Gas - COPERGAS, Recife, PE (Brazil)
2004-07-01
At Araripe Gypsum Site, Pernambuco State, gypsum is dehydrated to produce plaster using wood and BPF oil as major fuels, which generate serious environmental impacts. Natural gas provides important advantages over conventional fuels. Using this gas improves the thermal efficiency of direct contact process, producing no contamination in final product, also reducing considerably environmental pollution levels. In this scope, a rotate kiln was designed in pilot scale, where was carried out gypsum dehydration tests to produce beta plaster using natural gas. In this work are presented mathematical models to simulate the axial profiles of the gypsum conversion and the gas and solid temperatures on the axial length of the kiln. The mathematical models are used as restrictions to obtention of the operational optimized conditions to a minimum gypsum conversion of the 85%. The simulation results were compared to experimental ones and were obtained a good agreement between both the values. (author)
17. Antihyperalgesic efficacy of 5% lidocaine medicated plaster in capsaicin and sunburn pain models--two randomized, double-blinded, placebo-controlled crossover trials in healthy volunteers.
Science.gov (United States)
Gustorff, Burkhard; Hauer, David; Thaler, Johannes; Seis, Astrid; Draxler, Julia
2011-12-01
The aim of this research is to analyze analgesic efficacy of the 5% lidocaine medicated plaster in two randomized, double-blinded, placebo-controlled, crossover studies in 16 healthy volunteers using capsaicin and sunburn pain models. Lidocaine and placebo plasters were simultaneously applied to forearms and thighs at contralateral body sites for three alternating 12-h plaster-on/plaster-off periods. Between the second and third plaster-on period, 4.2-cm circular spots on both pretreated thighs were irradiated with three times the individual minimal erythema dose of UVB light. After the last plaster-on period, 20 μl of 0.1% capsaicin was injected intradermally into both forearms. The study was repeated using a single 12-h plaster application. The area of pinprick hyperalgesia was diminished by 53% (p sunburn model; the intensity of mechanical hyperalgesia to rigid filaments (8 - 512 mN) was reduced in both models. Cold pain perception threshold was reduced (19.7°C ± 8.0 vs 21.8°C ± 6.8 for placebo, p sunburn). Similar effects were observed in the 12-h exposure study. No effect was seen on capsaicin-induced spontaneous pain and flare size, or blood flow in the sunburn area, and heat hyperalgesia in either study. Lidocaine plaster effectively treats mechanical hyperalgesia and cold pain.
18. Agreement in the determination of preformed wire shape templates on plaster models and customized digital arch form diagrams on digital models.
Science.gov (United States)
Camardella, Leonardo Tavares; Sá, Maiara da Silva Bezerra; Guimarães, Luciana Campos; Vilella, Beatriz de Souza; Vilella, Oswaldo de Vasconcellos
2018-03-01
The aim of this study was to verify the accuracy of preformed wire shape templates on plaster models and those of customized digital arch form diagrams on digital models. Twenty pairs of dental plaster models were randomly selected from the archives of the Department of Orthodontics of Federal Fluminense University, Niterói, Rio de Janeiro, Brazil. All plaster model samples were scanned in a plaster model scanner to create the respective digital models. Three examiners defined the arch form on the mandibular arch of these models by selecting the ideal preformed wire shape template on each plaster model or by making a customized digital arch form on the digital models using a digital arch form customization tool. These 2 arch forms were superimposed by the best-fit method. The greatest differences in the 6 regions on the superimposed arches were evaluated. Each examiner presented a descriptive analysis with the means, standard deviation, and minimum and maximum intervals of the differences on the superimpositions. Intraclass correlation coefficient and paired t tests were used to evaluate the accuracy of the superimpositions. Among the 6 regions analyzed in the superimpositions, the largest differences in the anterior and premolar regions were considered clinically insignificant, whereas the largest differences in the right molar region, especially the second molar area, were considered clinically significant by all 3 examiners. The intraclass correlation coefficients showed a weak correlation in the premolar region and moderate correlations in the anterior and molar regions. The paired t test showed statistically significant differences in the left anterior and premolar regions. The superimpositions between the arch forms on plaster and digital models were considered accurate, and the differences were not clinically significant, with the exception of the second molar area. Despite the favorable results, the requirement of correcting some software problems may
19. Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis.
Directory of Open Access Journals (Sweden)
Fan Zhang
Full Text Available Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models.Two types of dental models (intraoral scan and plaster model of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model.There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm.The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models.
20. Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis
Science.gov (United States)
2016-01-01
Purpose Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models. Materials and Methods Two types of dental models (intraoral scan and plaster model) of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model. Results There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm. Conclusions The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models. PMID:27304976
1. Computational modeling of latent-heat-storage in PCM modified interior plaster
Energy Technology Data Exchange (ETDEWEB)
Fořt, Jan; Maděra, Jiří; Trník, Anton; Pavlíková, Milena; Pavlík, Zbyšek [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)
2016-06-08
The latent heat storage systems represent a promising way for decrease of buildings energy consumption with respect to the sustainable development principles of building industry. The presented paper is focused on the evaluation of the effect of PCM incorporation on thermal performance of cement-lime plasters. For basic characterization of the developed materials, matrix density, bulk density, and total open porosity are measured. Thermal conductivity is accessed by transient impulse method. DSC analysis is used for the identification of phase change temperature during the heating and cooling process. Using DSC data, the temperature dependent specific heat capacity is calculated. On the basis of the experiments performed, the supposed improvement of the energy efficiency of characteristic building envelope system where the designed plasters are likely to be used is evaluated by a computational analysis. Obtained experimental and computational results show a potential of PCM modified plasters for improvement of thermal stability of buildings and moderation of interior climate.
2. Rapid prototyping of a complex model for the manufacture of plaster molds for slip casting ceramic
Directory of Open Access Journals (Sweden)
D. P. C. Velazco
2014-12-01
3. Synthesis of Plaster for moulers's elaboration of imprint denture
International Nuclear Information System (INIS)
Hamiane, M; Rabahi, N; Saidi, M; Salhi, M
2012-01-01
Our goal was the synthesis of plaster from local raw materials to be used in denture mouler's. The plaster type α and β was synthesis by hydrothermal and dry method from gypsum (CaSO4. 2H2O) of the west Algerian. After crushing and mineralogical analysis, gypsum has undergone through cooking in an oven at a temperature (T = 200 ° C), for a time t = 4 hours. The synthesis and characterization of the product has involved several ways investigated as diffraction RX, X-ray fluorescence, time taken, electron microscope (MEB), hardness, SSB, compressive and bending strength and Ph. A digester horizontal type Toni - technical laboratory was used for the synthesis of plasterα. The results are conformable with the standard and plaster synthesized can be a basic material in the manufacture of moulers imprint denture.
4. Synthesis of Plaster for moulers's elaboration of imprint denture
Science.gov (United States)
Hamiane, M.; Rabahi, N.; Saidi, M.; Salhi, M.
2012-02-01
Our goal was the synthesis of plaster from local raw materials to be used in denture mouler's. The plaster type α and β was synthesis by hydrothermal and dry method from gypsum (CaSO4. 2H2O) of the west Algerian. After crushing and mineralogical analysis, gypsum has undergone through cooking in an oven at a temperature (T = 200 ° C), for a time t = 4 hours. The synthesis and characterization of the product has involved several ways investigated as diffraction RX, X-ray fluorescence, time taken, electron microscope (MEB), hardness, SSB, compressive and bending strength and Ph. A digester horizontal type Toni - technical laboratory was used for the synthesis of plasterα. The results are conformable with the standard and plaster synthesized can be a basic material in the manufacture of moulers imprint denture.
5. Impacts of a clay plaster on indoor air quality assessed using chemical and sensory measurements
DEFF Research Database (Denmark)
Darling, Erin K.; Cros, Clement J.; Wargocki, Pawel
2012-01-01
plaster as a PRM for improving air quality by controlling ozone, perceived air quality (PAQ) was determined in the presence of eight combinations of an emitting and reactive pollutant source (new carpet), clay plaster applied to gypsum wallboard, and chamber air with and without ozone. A panel of 24 human....... Perceived air quality was most acceptable and concentrations of aldehydes were lowest when only clay plaster or both clay plaster and carpet were present in the chambers without ozone. The least acceptable PAQ and the highest concentrations of aldehydes were observed when carpet and ozone were present...... together; addition of clay plaster for this condition improved PAQ and considerably decreased aldehyde concentrations....
6. Does the contact time of alginate with plaster cast influence its properties?
Directory of Open Access Journals (Sweden)
Mariana Marquezan
Full Text Available The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1 - with time of contact of 1 hour; and Group 2 (G2 - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan, respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05 between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.
7. Does the contact time of alginate with plaster cast influence its properties?
Directory of Open Access Journals (Sweden)
Mariana Marquezan
2012-06-01
Full Text Available The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1 - with time of contact of 1 hour; and Group 2 (G2 - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan, respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05 between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.
8. Linear dimensional changes in plaster die models using different elastomeric materials
Directory of Open Access Journals (Sweden)
Jefferson Ricardo Pereira
2010-09-01
Full Text Available Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05 and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD=15.0 µm, EF = 14.6 µm, GH=15.2 µm, mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm, polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm. All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.
9. Visible and Mid-Infrared Gypsum Optical Constants for Modeling of Martian Deposits
Science.gov (United States)
Roush, Ted L.; Esposito, Francesca; Rossmann, George R.; Colangeli, Luigi
2007-08-01
Introduction: Recent and on-going remote and in situ observations indicate that sulfates are present in significant abundances at various locations on Mars [1-7]. The Mars Reconnaissance Orbiter (MRO) imaging spectrometer (CRISM) is returning hyperspectral data at higher spatial resolution [8] than the OMEGA instrument on the Mars Express Mission [3]. Data from both OMEGA and CRISM have provided spectral evidence for the presence of gypsum and various hydrated sulfates on the Martian surface [e.g. 3-7] Thus, the optical properties of sulfates, in general, are of interest to quantitative interpretation of this increasing volume of remotely sensed data. This is because optical constants describe how a material interacts with electromagnetic radiation and represent the fundamental values used in radiative transfer calculations describing a variety of physical environments. Such environments include atmospheres where aerosols are present, planetary and satellite regoliths, and circumstellar dust clouds. Here we focus upon gypsum because of its applicability due to its identification on Mars. Also, gypsum is a mineral that is readily available in samples sizes that are suitable for study using a variety of spectral measurements. In the infrared (>5 μm) several studies reporting the optical constants of gypsum can be used in evaluating the approach used here. Most importantly, there is a general lack of data regarding the optical constants for gypsum at visible and mid-infrared wavelengths (0.4-5 μm) that are being observed by OMEGA and CRISM. Background: In the infrared, there have been several studies focused at determining the optical constants of gypsum using classical dispersion models [9-11]. These have used a variety of samples including; crystals, compressed pellets of pure materials, and grains suspended in a KBr matrix. Spectral measurements of gypsum, and other sulfates, have existed for about 100 years at visible and mid-infrared wavelengths (0.4-5 μm) [e
10. Virtualizing ancient Rome: 3D acquisition and modeling of a large plaster-of-Paris model of imperial Rome
Science.gov (United States)
Guidi, Gabriele; Frischer, Bernard; De Simone, Monica; Cioci, Andrea; Spinetti, Alessandro; Carosso, Luca; Micoli, Laura L.; Russo, Michele; Grasso, Tommaso
2005-01-01
Computer modeling through digital range images has been used for many applications, including 3D modeling of objects belonging to our cultural heritage. The scales involved range from small objects (e.g. pottery), to middle-sized works of art (statues, architectural decorations), up to very large structures (architectural and archaeological monuments). For any of these applications, suitable sensors and methodologies have been explored by different authors. The object to be modeled within this project is the "Plastico di Roma antica," a large plaster-of-Paris model of imperial Rome (16x17 meters) created in the last century. Its overall size therefore demands an acquisition approach typical of large structures, but it also is characterized extremely tiny details typical of small objects (houses are a few centimeters high; their doors, windows, etc. are smaller than 1 centimeter). This paper gives an account of the procedures followed for solving this "contradiction" and describes how a huge 3D model was acquired and generated by using a special metrology Laser Radar. The procedures for reorienting in a single reference system the huge point clouds obtained after each acquisition phase, thanks to the measurement of fixed redundant references, are described. The data set was split in smaller sub-areas 2 x 2 meters each for purposes of mesh editing. This subdivision was necessary owing to the huge number of points in each individual scan (50-60 millions). The final merge of the edited parts made it possible to create a single mesh. All these processes were made with software specifically designed for this project since no commercial package could be found that was suitable for managing such a large number of points. Preliminary models are presented. Finally, the significance of the project is discussed in terms of the overall project known as "Rome Reborn," of which the present acquisition is an important component.
11. Development of materials that cover the deposits of gypsum exploited in the polo plasterer in Pernambuco; Aproveitamento dos materiais que recobrem as jazidas de gipsita explotadas no polo gesseiro de Pernambuco
Energy Technology Data Exchange (ETDEWEB)
Rego, S.A.B.C.; Moraes, A.S. de; Anjos, I.F. dos, E-mail: [email protected] [Universidade Federal de Pernambuco (UFPE), PE (Brazil); Lira, B.B. [Universidade Federal da Paraiba (UFPB), PB (Brazil)
2012-07-01
The mineral clay found on the surface of gypsum deposits in the region of Recife - PE are considered mining tailings and job search reference in new industrial applications for these minerals, ores. In this context, we performed the characterization of these materials with the purpose of its use as inorganic pigments in the ceramic coating. These minerals present 'in locus' different colors ranging from beige to reddish. After heat treatment at 1000° C their colors have varied tones that can be used as natural pigments in the ceramic industry. The techniques of fluorescence X-ray diffraction X-ray, infrared and colorimetry were applied in the characterization of mineral-ore in question. Using mineral processing techniques we obtain a physical separation of clay minerals associated. The use of concentrated after processing showed that the material has the potential to replace traditional pigments used in ceramic industry, and thus represent a new alternative on the market of natural pigments. Another potential comprehensive analysis of the material is its use associated with polymers in order to develop new materials. (author)
12. Accuracy of three-dimensional cone beam computed tomography digital model measurements compared with plaster study casts
Directory of Open Access Journals (Sweden)
Shuaib Al Ali
2017-01-01
Full Text Available Purpose: The purpose of this study was to assess the accuracy of three-dimensional (3D cone beam computed tomography (CBCT study casts by comparing with direct measurements taken from plaster study casts. Materials and Methods: The dental arches of 30 patient subjects were imaged with a Kodak 9300 3D CBCT devise; Anatomodels were created and in vivo 5 imaging software was used to measure 10 dental arch variables which were compared to measurements of plaster study casts. Results: Three of the 10 variables, i.e., overbite, maxillary intermolar width, and arch length, were found significantly smaller (P < 0.05 using the Anatomodels following nonparametric Wilcoxon signed-rank testing. None of the differences found in the study averaged <0.5 mm. Conclusions: 3D CBCT imaging provided clinically acceptable accuracy for dental arch analysis. 3D CBCT imaging tended to underestimate the actual measurement compared to plaster study casts.
13. Plaster-Wrap Dragons
Science.gov (United States)
Vance, Shelly
2012-01-01
In this article, the author describes how her students constructed a three-dimensional sculpture of a dragon using plaster wrap and other materials. The dragons were formed from modest means--using only a toilet-paper tube, newsprint, tape and wire.
14. Analysis of gypsum ore conversion with aid of gamma-ray transmission and CCRD
International Nuclear Information System (INIS)
Vasconcelos, W.E.; Dantas, C.C.; Lira, C.A.B.O.; Narain, R.; Santos, V.A.
2009-01-01
Nowadays, except for very few kettles imported, the monitoring of the conversion of the produced plaster at the Pole Plaster of Araripe is not done with aid of on-line techniques. It shows a simulation of operational conditions with an online meter of chemically combined water in plaster, by means of Central Composite Rotatable Designs (CCRD) and nuclear technique of gamma-ray transmission. In the family of central composite rotatable designs, the CCRD is more efficient than the others, regarding uniformity of variances of the points at the same distance from the center of the design. It is a simulation of operational conditions with an online meter of chemically combined water in plaster, by means of nuclear technique of gamma radiation transmission. Such determination can be achieved by the effect caused by the variation of the mass attenuation coefficient of the dehydrated partially material. An Americium-241 gamma source (60 keV) was simulated in the implementation of the Beer-Lambert equation. The nuclear data required for simulation were obtained from XMuDat software, available from site of the International Atomic Energy Agency. A program in Matlab programming language has demonstrated the possibility of monitoring at all stages of the dehydration process with measures of the specific mass of the sample having an estimated error of the order of 1%. To verify the operating conditions suitable for the process, experiments were simulated using a CCRD. The independent variables were the thickness sample and chemically combined water in plaster. Optimal conditions of the process were determined (STATISTICA software, Release 7.0), which allowed the derivation of a model represented by response surface of the gypsum conversion. (author)
15. Automatic gender determination from 3D digital maxillary tooth plaster models based on the random forest algorithm and discrete cosine transform.
Science.gov (United States)
Akkoç, Betül; Arslan, Ahmet; Kök, Hatice
2017-05-01
One of the first stages in the identification of an individual is gender determination. Through gender determination, the search spectrum can be reduced. In disasters such as accidents or fires, which can render identification somewhat difficult, durable teeth are an important source for identification. This study proposes a smart system that can automatically determine gender using 3D digital maxillary tooth plaster models. The study group was composed of 40 Turkish individuals (20 female, 20 male) between the ages of 21 and 24. Using the iterative closest point (ICP) algorithm, tooth models were aligned, and after the segmentation process, models were transformed into depth images. The local discrete cosine transform (DCT) was used in the process of feature extraction, and the random forest (RF) algorithm was used for the process of classification. Classification was performed using 30 different seeds for random generator values and 10-fold cross-validation. A value of 85.166% was obtained for average classification accuracy (CA) and a value of 91.75% for the area under the ROC curve (AUC). A multi-disciplinary study is performed here that includes computer sciences, medicine and dentistry. A smart system is proposed for the determination of gender from 3D digital models of maxillary tooth plaster models. This study has the capacity to extend the field of gender determination from teeth. Copyright © 2017 Elsevier B.V. All rights reserved.
16. Collapse susceptibility mapping in karstified gypsum terrain (Sivas basin - Turkey) by conditional probability, logistic regression, artificial neural network models
Science.gov (United States)
Yilmaz, Isik; Keskin, Inan; Marschalko, Marian; Bednarik, Martin
2010-05-01
This study compares the GIS based collapse susceptibility mapping methods such as; conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) applied in gypsum rock masses in Sivas basin (Turkey). Digital Elevation Model (DEM) was first constructed using GIS software. Collapse-related factors, directly or indirectly related to the causes of collapse occurrence, such as distance from faults, slope angle and aspect, topographical elevation, distance from drainage, topographic wetness index- TWI, stream power index- SPI, Normalized Difference Vegetation Index (NDVI) by means of vegetation cover, distance from roads and settlements were used in the collapse susceptibility analyses. In the last stage of the analyses, collapse susceptibility maps were produced from CP, LR and ANN models, and they were then compared by means of their validations. Area Under Curve (AUC) values obtained from all three methodologies showed that the map obtained from ANN model looks like more accurate than the other models, and the results also showed that the artificial neural networks is a usefull tool in preparation of collapse susceptibility map and highly compatible with GIS operating features. Key words: Collapse; doline; susceptibility map; gypsum; GIS; conditional probability; logistic regression; artificial neural networks.
17. Hydrogeology of Gypsum formations
Directory of Open Access Journals (Sweden)
Klimchouk A.
1996-01-01
Full Text Available Detailed explanation of hydrogeological characteristics of gypsum aquifers is given in various situations: deep-seated karst-confined conditions, subjacent, entrenched and denuded karst types-semi-confined, phreatic and vadose conditions. The hydrogeological evolution of barren exposed gypsum karst and flow velocities in gypsum karst aquifers is also discussed.
18. Gypsum crystals observed in experimental and natural sea ice
Science.gov (United States)
Geilfus, N.-X.; Galley, R. J.; Cooper, M.; Halden, N.; Hare, A.; Wang, F.; Søgaard, D. H.; Rysgaard, S.
2013-12-01
gypsum has been predicted to precipitate in sea ice, it has never been observed. Here we provide the first report on gypsum precipitation in both experimental and natural sea ice. Crystals were identified by X-ray diffraction analysis. Based on their apparent distinguishing characteristics, the gypsum crystals were identified as being authigenic. The FREeZing CHEMistry (FREZCHEM) model results support our observations of both gypsum and ikaite precipitation at typical in situ sea ice temperatures and confirms the "Gitterman pathway" where gypsum is predicted to precipitate. The occurrence of authigenic gypsum in sea ice during its formation represents a new observation of precipitate formation and potential marine deposition in polar seas.
19. Gypsum crystals observed in experimental and natural sea ice
DEFF Research Database (Denmark)
Geilfus, Nicolas-Xavier; Galley, Ryan; Cooper, Marc
2013-01-01
, the gypsum crystals were identified as being authigenic. The FREeZing CHEMistry (FREZCHEM) model results support our observations of both gypsum and ikaite precipitation at typical in situ sea ice temperatures and confirms the “Gitterman pathway” where gypsum is predicted to precipitate. The occurrence...
20. MODIFIED GYPSUM BINDER
Directory of Open Access Journals (Sweden)
KONDRATEVA N. V.
2017-02-01
Full Text Available Summary. Statement of the problem. A disadvantage of the gypsum binder is the limited water resistance of products that historically led to the use of gypsum products mostly for internal construction and finishing works. To regulate the process of hydration and structure formation of the use of chemical additives that are introduced with the mixing water or in the production of the binder. As a rule, substances that increase the solubility of the gypsum binder referred to as the hardening accelerator, and substances which retard the solubility of the inhibitors of hardening of the mixture. Most accelerators and retarders hardening affect adversely on the final strength of the mixture. More effective impact on gypsum binder additives have plasticizers. The purpose of the article. Getting gypsum binder modified with the aim of improving its water resistance and improvement of some technological factors (the time of hardening, water gypsum ratio, etc. would reduce its shortcomings and expand the scope of application of the binder. Conclusion. The result of the research reviewed changes in the basic properties of the gypsum binder with the introduction of additives, plasticizers, and selected the most effective supplements to significantly reduce water gypsum ratio, to improve strength properties and to obtain gypsum binder more dense structure.
1. Topical Anti-Inflammatory and Analgesic Effects of Multiple Applications of S(+)-Flurbiprofen Plaster (SFPP) in a Rat Adjuvant-Induced Arthritis Model.
Science.gov (United States)
Sugimoto, Masanori; Toda, Yoshihisa; Hori, Miyuki; Mitani, Akiko; Ichihara, Takahiro; Sekine, Shingo; Kaku, Shinsuke; Otsuka, Noboru; Matsumoto, Hideo
2016-06-01
Preclinical Research The aim of this study was to evaluate the efficacy of multiple applications of S(+)-flurbiprofen plaster (SFPP), a novel Nonsteroidal anti-inflammatory drug (NSAID) patch, for the alleviation of inflammatory pain and edema in rat adjuvant-induced arthritis (AIA) model as compared to other NSAID patches. The AIA model was induced by the injection of Mycobacterium butyricum and rats were treated with a patch (1.0 cm × 0.88 cm) containing each NSAID (SFP, ketoprofen, loxoprofen, diclofenac, felbinac, flurbiprofen, or indomethacin) applied to the paw for 6 h per day for 5 days. The pain threshold was evaluated using a flexion test of the ankle joint, and the inflamed paw edema was evaluated using a plethysmometer. cyclooxygenase (COX)-1 and COX-2 inhibition was evaluated using human recombinant proteins. Multiple applications of SFPP exerted a significant analgesic effect from the first day of application as compared to the other NSAID patches. In terms of paw edema, SFPP decreased edema from the second day after application, Multiple applications of SFPP were superior to those of other NSAID patches, in terms of the analgesic effect with multiple applications. These results suggest that SFPP may be a beneficial patch for providing analgesic and anti-inflammatory effects clinically. Drug Dev Res 77 : 206-211, 2016. © 2016 The Authors Drug Development Research Published by Wiley Periodicals, Inc. © 2016 The Authors Drug Development Research Published by Wiley Periodicals, Inc.
2. Topical Anti‐Inflammatory and Analgesic Effects of Multiple Applications of S(+)‐Flurbiprofen Plaster (SFPP) in a Rat Adjuvant‐Induced Arthritis Model
Science.gov (United States)
Toda, Yoshihisa; Hori, Miyuki; Mitani, Akiko; Ichihara, Takahiro; Sekine, Shingo; Kaku, Shinsuke; Otsuka, Noboru; Matsumoto, Hideo
2016-01-01
Abstract Preclinical Research The aim of this study was to evaluate the efficacy of multiple applications of S(+)‐flurbiprofen plaster (SFPP), a novel Nonsteroidal anti‐inflammatory drug (NSAID) patch, for the alleviation of inflammatory pain and edema in rat adjuvant‐induced arthritis (AIA) model as compared to other NSAID patches. The AIA model was induced by the injection of Mycobacterium butyricum and rats were treated with a patch (1.0 cm × 0.88 cm) containing each NSAID (SFP, ketoprofen, loxoprofen, diclofenac, felbinac, flurbiprofen, or indomethacin) applied to the paw for 6 h per day for 5 days. The pain threshold was evaluated using a flexion test of the ankle joint, and the inflamed paw edema was evaluated using a plethysmometer. cyclooxygenase (COX)−1 and COX‐2 inhibition was evaluated using human recombinant proteins. Multiple applications of SFPP exerted a significant analgesic effect from the first day of application as compared to the other NSAID patches. In terms of paw edema, SFPP decreased edema from the second day after application, Multiple applications of SFPP were superior to those of other NSAID patches, in terms of the analgesic effect with multiple applications. These results suggest that SFPP may be a beneficial patch for providing analgesic and anti‐inflammatory effects clinically. Drug Dev Res 77 : 206–211, 2016. © 2016 The Authors Drug Development Research Published by Wiley Periodicals, Inc. PMID:27241582
3. Thermophysical properties of hydrophobised lime plasters - The influence of ageing
Science.gov (United States)
Pavlíková, Milena; Zemanová, Lucie; Pavlík, Zbyšek
2017-07-01
The building envelope is a principal responsible for buildings energy loses. Lime plasters as the most popular finishing materials of historical buildings and culture monuments influence the thermal behaviour as well as construction material of masonry. On this account, the effect of ageing on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime plaster is tested. The ageing is accelerated with controlled carbonation process to simulate the final plasters properties. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity are experimentally assessed using a transient impulse method. The obtained data revealed the significant changes of the both studied thermal parameters in the dependence on plasters composition and age. The assessed material parameters will be stored in a material database, where will find use as an input data for computational modelling of heat transport in this type of porous building materials and evaluation of energy-savings and sustainability issues.
4. Consolidation of renders and plasters
Czech Academy of Sciences Publication Activity Database
van Hees, R.; Veiga, R.; Slížková, Zuzana
2017-01-01
Roč. 50, č. 1 (2017), s. 50-65 ISSN 1359-5997 R&D Projects: GA MŠk(CZ) LO1219 Keywords : consolidants * plasters * requirements * selection * assessment Subject RIV: AL - Art, Architecture, Cultural Heritage OBOR OECD: Materials engineering Impact factor: 2.607, year: 2016 http://link.springer.com/article/10.1617/s11527-016-0894-5
5. Analgesic Effect of the Newly Developed S(+)-Flurbiprofen Plaster on Inflammatory Pain in a Rat Adjuvant-Induced Arthritis Model.
Science.gov (United States)
Sugimoto, Masanori; Toda, Yoshihisa; Hori, Miyuki; Mitani, Akiko; Ichihara, Takahiro; Sekine, Shingo; Hirose, Takuya; Endo, Hiromi; Futaki, Nobuko; Kaku, Shinsuke; Otsuka, Noboru; Matsumoto, Hideo
2016-02-01
Preclinical Research This article describes the properties of a novel topical NSAID (Nonsteroidal anti-inflammatory drug) patch, SFPP (S(+)-flurbiprofen plaster), containing the potent cyclooxygenase (COX) inhibitor, S(+)-flurbiprofen (SFP). The present studies were conducted to confirm human COX inhibition and absorption of SFP and to evaluate the analgesic efficacy of SFPP in a rat adjuvant-induced arthritis (AIA) model. COX inhibition by SFP, ketoprofen and loxoprofen was evaluated using human recombinant COX proteins. Absorption of SFPP, ketoprofen and loxoprofen from patches through rat skin was assessed 24 h after application. The AIA model was induced by injecting Mycobacterium tuberculosis followed 20 days later by the evaluation of the prostaglandin PGE2 content of the inflamed paw and the pain threshold. SFP exhibited more potent inhibitory activity against COX-1 (IC50 = 8.97 nM) and COX-2 (IC50 = 2.94 nM) than the other NSAIDs evaluated. Absorption of SFP was 92.9%, greater than that of ketoprofen and loxoprofen from their respective patches. Application of SFPP decreased PGE2 content from 15 min to 6 h and reduced paw hyperalgesia compared with the control, ketoprofen and loxoprofen patches. SFPP showed analgesic efficacy, and was superior to the ketoprofen and loxoprofen patches, which could be through the potent COX inhibitory activity of SFP and greater skin absorption. The results suggested SFPP can be expected to exert analgesic effect clinically. © 2016 The Authors Drug Development Research Published by Wiley Periodicals, Inc.
6. Analgesic Effect of the Newly Developed S(+)‐Flurbiprofen Plaster on Inflammatory Pain in a Rat Adjuvant‐Induced Arthritis Model
Science.gov (United States)
Toda, Yoshihisa; Hori, Miyuki; Mitani, Akiko; Ichihara, Takahiro; Sekine, Shingo; Hirose, Takuya; Endo, Hiromi; Futaki, Nobuko; Kaku, Shinsuke; Otsuka, Noboru; Matsumoto, Hideo
2016-01-01
ABSTRACT Preclinical Research This article describes the properties of a novel topical NSAID (Nonsteroidal anti‐inflammatory drug) patch, SFPP (S(+)‐flurbiprofen plaster), containing the potent cyclooxygenase (COX) inhibitor, S(+)‐flurbiprofen (SFP). The present studies were conducted to confirm human COX inhibition and absorption of SFP and to evaluate the analgesic efficacy of SFPP in a rat adjuvant‐induced arthritis (AIA) model. COX inhibition by SFP, ketoprofen and loxoprofen was evaluated using human recombinant COX proteins. Absorption of SFPP, ketoprofen and loxoprofen from patches through rat skin was assessed 24 h after application. The AIA model was induced by injecting Mycobacterium tuberculosis followed 20 days later by the evaluation of the prostaglandin PGE2 content of the inflamed paw and the pain threshold. SFP exhibited more potent inhibitory activity against COX‐1 (IC50 = 8.97 nM) and COX‐2 (IC50 = 2.94 nM) than the other NSAIDs evaluated. Absorption of SFP was 92.9%, greater than that of ketoprofen and loxoprofen from their respective patches. Application of SFPP decreased PGE2 content from 15 min to 6 h and reduced paw hyperalgesia compared with the control, ketoprofen and loxoprofen patches. SFPP showed analgesic efficacy, and was superior to the ketoprofen and loxoprofen patches, which could be through the potent COX inhibitory activity of SFP and greater skin absorption. The results suggested SFPP can be expected to exert analgesic effect clinically. Drug Dev Res 76 : 20–28, 2016. © 2016 Wiley Periodicals, Inc. PMID:26763139
7. Compaction of FGD-gypsum
NARCIS (Netherlands)
Stoop, B.T.J.; Larbi, J.A.; Heijnen, W.M.M.
1996-01-01
It is shown that it is possible to produce compacted gypsum with a low porosity and a high strength on a laboratory scale by uniaxial compaction of flue gas desulphurization (FGD-) gypsum powder. Compacted FGD-gypsum cylinders were produced at a compaction pres-sure between 50 and 500 MPa yielding
8. Gypsum accumulation on carbonate stone
Science.gov (United States)
McGee, E.S.; Mossotti, V.G.
1992-01-01
The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.
9. Gypsum karst in Great Britain
Directory of Open Access Journals (Sweden)
Cooper A.H.
1996-01-01
Full Text Available In Great Britain the most spectacular gypsum karst development is in the Zechstein gypsum (late Permian mainly in north-eastern England. The Midlands of England also has some karst developed in the Triassic gypsum in the vicinity of Nottingham. Along the north-east coast, south of Sunderland, well-developed palaeokarst, with magnificent breccia pipes, was produced by dissolution of Permian gypsum. In north-west England a small gypsum cave system of phreatic origin has been surveyed and recorded. A large actively evolving phreatic gypsum cave system has been postulated beneath the Ripon area on the basis of studies of subsidence and boreholes. The rate of gypsum dissolution here, and the associated collapse lead to difficult civil engineering and construction conditions, which can also be aggravated by water abstraction.
10. The hydrophobic modification of gypsum binder by peat products: physico-chemical and technological basis
Directory of Open Access Journals (Sweden)
O. Misnikov
2018-04-01
Full Text Available Gypsum binder is a quick-setting and fast-hardening material that is used widely in the construction industry for plastering and as an ingredient of concrete, other binding materials, etc. The issue addressed here is its short shelf life (around three months which arises because it is hygroscopic, i.e. it readily absorbs moisture and begins to set during transport and storage. The main methods that are currently available for protecting gypsum binder against unwanted exposure to moisture and water vapour are considered, and hydrophobic modification with the bitumen released during peat thermolysis (a method previously considered for cement is proposed as a promising alternative. Because there is overlap in the temperature ranges used in the manufacture of gypsum binder and those required for the initial stages of thermal decomposition of the organic matter in peat, it is expected that hydrophobisation could be achieved during the established manufacturing process without any changes to plant or procedures. The optimum concentration of organic (peat additive for gypsum rock mined from the Shushokskoye deposit in Russia is derived experimentally. With 0.5–1 % of peat additive, the strength grading of the gypsum plaster is preserved and its storage time without caking and hydration increases, even under adverse conditions (100 % relative humidity. The proposed method is compatible with current gypsum production technology, it does not require any changes in equipment, and the prices of mineral raw materials and semi-finished peat products are approximately the same. Thus, the incorporation of hydrophobic modification using peat into the manufacturing process for gypsum binder is unlikely to increase the cost of the product.
11. Mechanism of gypsum hydration
Directory of Open Access Journals (Sweden)
Pacheco, G.
1991-06-01
Full Text Available There is an hypothesis that the mechanism o f gypsum hydration and dehydration is performed through two simultaneous phenomena. In this study we try to clear up this phenomenon using chlorides as accelerators or a mixture of ethanol-methanol as retarders to carry out the gypsum setting. Natural Mexican gypsum samples and a hemihydrate prepared in the laboratory are used. The following analytical techniques are used: MO, DRX, DTA, TG and DTG. In agreement with the obtained results, it can be concluded: that colloid formation depends on the action of accelerators or retarders and the crystals are a consequence of the quantity of hemihydrate formed.
En el mecanismo de hidratación y deshidratación del yeso existe la hipótesis de que éste se efectúa por dos fenómenos simultáneos. Este estudio intenta esclarecer estos fenómenos, empleando: cloruros como aceleradores o mezcla etanol-metanol como retardadores para efectuar el fraguado del yeso. Se emplean muestras de yeso de origen natural mexicano y hemihydrate preparado en laboratorio; se utilizan técnicas analíticas: MO, DRX, DTA, TG y DTG. De acuerdo a los resultados obtenidos se puede deducir: que la formación del coloide depende de la acción de los agentes aceleradores o retardadores y que los cristales son consecuencia de la cantidad de hemihidrato formado.
12. Unravelling the mechanisms for plant survival on gypsum soils: an analysis of the chemical composition of gypsum plants from Turkey.
Science.gov (United States)
Bolukbasi, A; Kurt, L; Palacio, S
2016-03-01
Depending on their specificity to gypsum, plants can be classified as gypsophiles (gypsum exclusive) and gypsovags (non-exclusive). The former may further be segregated into wide and narrow gypsophiles, depending on the breadth of their distribution area. Narrow gypsum endemics have a putative similar chemical composition to plants non-exclusive to gypsum (i.e. gypsovags), which may indicate their similar ecological strategy as stress-tolerant plant refugees on gypsum. However, this hypothesis awaits testing in different regions of the world. We compared the chemical composition of four narrow gypsum endemics, one widely distributed gypsophile and six gypsovags from Turkey. Further, we explored the plasticity in chemical composition of Turkish gypsovags growing on high- and low-gypsum content soils. Differences were explored with multivariate analyses (RDA) and mixed models (REML). Narrow gypsum endemics segregated from gypsovags in their chemical composition according to RDAs (mainly due to higher K and ash content in the former). Nevertheless, differences were small and disappeared when different nutrients were analysed individually. All the gypsovags studied accumulated more S and ash when growing on high-gypsum than on low-gypsum soils. Similar to narrow gypsum endemics from other regions of the world, most local gypsum endemics from Turkey show a similar chemical composition to gypsovags. This may indicate a shared ecological strategy as stress-tolerant plants not specifically adapted to gypsum. Nevertheless, the narrow gypsum endemic Gypsophila parva showed a chemical composition typical of gypsum specialists, indicating that various strategies are feasible within narrowly distributed gypsophiles. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.
13. Palatal Surface Area of Maxillary Plaster Casts
DEFF Research Database (Denmark)
Darvann, Tron Andre; Hermann, Nuno V.; Ersbøll, Bjarne Kjær
2007-01-01
Objective: To investigate the relationship between corresponding two-dimensional and three-dimensional measurements on maxillary plaster casts taken from photographs and three-dimensional surface scans, respectively. Materials and Methods: Corresponding two-dimensional and three-dimensional measu...
14. Mineral of the month: gypsum
Science.gov (United States)
Founie, Alan
2004-01-01
The earliest known use of gypsum as a building material was in Anatolia (in what is now Turkey) around 6000 B.C. It has been found on the interiors of the great pyramids in Egypt, which were erected in about 3700 B.C. Now an average new American home contains more than 7 metric tons of gypsum in the form of more than 6,000 square feet of wallboard.
15. Salt damage of stone, plaster and painted layers at a medieval church, South-Hungary
Science.gov (United States)
Török, Ákos; Galambos, Éva
2016-04-01
The Chapel of Pécsvárad is one of the best preserved and oldest medieval stone monument in South Hungary. It dates back to the 11th century. The interior of the chapel is decorated with wall paintings, which are later and probably originating from the late 12th century. The wall painting is partly preserved and it is located on an interior stone wall of the chapel facing to the East. The wall painting shows various forms of damage from salt efflorescence to chipping. The current research provides information on the in situ and laboratory analyses of salts, plasters, pigments and stone material suggesting mechanisms of decay that lead to partial loss of the painting. Both on site techniques and laboratory analyses were performed. Imaging techniques such as UV luminescence and IR thermography were used to identify the moist and salt covered zones on the wall surface. Portable moisture meter were also applied to map the wet zones in the interior and also at the external part of the chapel. Schmidt hammer and Duroscop were used for testing the surface strength of stone. Laboratory tests were focused on mineralogical and chemical compositional analyses. Small samples of stone, mortar, plaster and pigments were tested by optical microscopy, SEM-EDX, XRD and Thermogravimetric analyses. According to our tests the chapel was predominantly made of porous limestone and sandstone. Laboratory analyses proved that the major salt responsible for the damage of external walls are gypsum and halite, while in the interior part higher amount of halite and significant amount of sodium-nitrate were found besides gypsum. The painted layers are on Byzantine-type of plaster with organic compounds (plant fragments) and with a substrate layer rich in calcium carbonate. The identified pigments are dominantly earth pigments such as iron-oxide containing red and yellow (ochre) and green earth. A unique preservation of ultramarine blue in Hungary was found on the wall painting. The partial
16. Model of gypsum, calcite and silica solubilities for application to geothermal waters over a wide range of temperature, P/sub CO/sub 2// and ionic strength. Final technical report, October 1, 1983-September 30, 1984
Energy Technology Data Exchange (ETDEWEB)
1984-01-01
This report describes the construction of a high temperature (25 to 250/sup 0/C), variable P/sub CO/sub 2// (1 to 40 atm), chemical model of mineral (including gypsum, calcite and amorphous silica) solubilities in the system: Na-K-Ca-H-Cl-SO/sub 4/-HCO/sub 3/-CO/sub 3/-CO/sub 2/-SiO/sub 2/-H/sub 2/O. This model was designed to support geothermal energy production needs.
17. Economics of Gypsum Production in Iran
Science.gov (United States)
Esmaeili, Abdoulkarim
The purpose of this research is to analyze the economics of gypsum production in Iran. The trend in production cost, selling price and profit are used to investigate economics of gypsum production. In addition, the multivariate time series method is used to determine factors affecting gypsum price in domestic market. The results indicated that due to increase in production and inflation, profitability of gypsum production has decreased during recent years. It is concluded that tariff and non-tariff barriers on mines machinery are among reasons for increasing production cost in Iranian gypsum mines. Decreasing such barriers could increase profitability of gypsum production in Iran.
18. The Jettencave, Southern Harz Mountains, Germany: Geophysical observations and a structural model of a shallow cave in gypsum/anhydrite-bearing rocks
Science.gov (United States)
Kaufmann, Georg; Romanov, Douchko
2017-12-01
Gypsum and anhydrite are soluble rocks, where fissures and bedding partings can be enlarged with time by the dissolution of the mineral species through water. The selective enlargement results in sub-surface voids acting as preferential flow path for the drainage of the rock. With time, larger cavities develop, and a network of cave passages can evolve. If the enlarged cave voids are not too deep under the surface, geophysical measurements can be used to detect, identify and trace these structures. We have used gravity measurements (GRAV), electrical resistivity imaging (ERI), self-potential measurements (SP), electrical conductivity measurements (EC), and ground-penetrating radar (GPR) above the cave Jettenhöhle, a cave located in the southern Harz Mountains in Germany. The Jettencave is developed in the Hauptanhydrit formation of the Permian Zechstein sequence, characterised by large breakdown rooms and an exposed water table. The overburden of the cave is only around 10-15 m, and dolomitic rocks are located in close vicinity. We present results from our geophysical surveys in vicinity of the cave. We are able to identify the cave geometry from GRAV, ERI, and GPR measurements, which distinguish the local lithology of the Permian Zechstein rocks in the area. From the ERI and EC measurements, we derive information on the void volume in the soluble rocks. We finally present a three-dimensional structural model of the Jettencave and its surroundings, based on our geophysical results and the hydrological interpretation.
19. Study of plaster finishes on San Pedro de los Francos church at Calatayud
Directory of Open Access Journals (Sweden)
Sánchez de Rojas, Mª I
2007-06-01
Full Text Available This study of the plaster finishes on San Pedro de los Francos Church at Calatayud revealed, firstly, the stratigraphic sequence based on the interpretation of the bonding interfaces; and secondly, the evolution of placement techniques from mudéjar style textured and painted false stonework (15th century to the smooth plastering and paint typical of later phases. Finally, scanning electron microscope (SEM, energy dispersive X-ray microanalysis (EDX and X-ray diffraction (XRD studies showed that gypsum and anhydrite are the main components of both binder and aggregate in these mortars. In other words, they constitute traditional multiphase plasters whose coarser particles or aggregate were a byproduct of the artisanal manufacturing process.El estudio de los enlucidos de la iglesia de San Pedro de los Francos de Calatayud ha permitido demostrar, en primer lugar, la secuencia estratigráfica mediante la lectura de la interfase de adherencia; en segundo lugar, la evolución de las técnicas de aplicación, desde el enlucido mudéjar, un fingido de piedra agramilado y pintado (siglo XV, hasta los enlucidos lisos y pinturas aplicados posteriormente. Y, finalmente, a través de los estudios de microscopía electrónica de barrido (SEM, microanálisis por energía dispersiva de rayos X (EDX y de difracción de rayos X (DRX, se ha determinado que son morteros en los que tanto el conglomerante como el árido son yeso y anhidrita, que correspondería a un yeso tradicional multifase, cuyos granos más gruesos analizados como áridos proceden del producto obtenido artesanalmente.
20. Cutaneous irritancy of an ibuprofen medicated plaster in healthy volunteers.
Science.gov (United States)
Maganji, Manisha; Connolly, Mark P; Bhatt, Aomesh
2018-04-01
To assess the irritation and contact sensitization potential of a 200 mg ibuprofen medicated plaster. This double-blind, phase-1 placebo controlled study had two phases; the induction phase to evaluate the irritant potential of continuous application of the plaster, and the challenge phase to assess contact sensitivity (allergy). The cumulative irritancy potential was evaluated using an adaptation of the Shelanski method. Healthy adults (≥18 years of age) (N = 210) were treated simultaneously with one ibuprofen medicated and one placebo plaster applied in a randomized fashion to either the left or right side of the lower back. During the induction phase, plasters were applied on Days 1, 3, 5, 8, 10, 12, 15, 17, and 19 and the final plaster removed on Day 22. At each scheduled visit plasters and applications sites were assessed for degree of adhesion and skin irritation (score of 1 = no irritation to 7 = strong reaction spreading beyond test sites), respectively. The challenge phase followed a two-week washout period. A plaster was applied on Day 36 for 48 h and assessment occurred on Days 38, 39, and 40. The mean cumulative irritation score during the induction phase was lower for the ibuprofen medicated plaster than the placebo plaster (0.32 vs. 1.23, respectively). Three (1.4%) subjects experience a dermal reaction of grade ≥3 for the ibuprofen medicated plaster compared with 27 (12.7%) for the placebo plaster. Following challenge with ibuprofen or placebo plasters, 12 subjects (6.2%) with the ibuprofen medicated plaster and four (2.2%) with the placebo plaster had skin reaction of assessment grade higher than the induction phase. One subject for the ibuprofen and two for the placebo plaster had reactions with grade >2. No subjects showed an increase in sensitization on Day 39 or 40 compared with Day 38. The findings indicate that the both the irritancy and contact sensitization of the ibuprofen medicated plaster is acceptable.
1. Growth of indoor fungi on gypsum
NARCIS (Netherlands)
Segers, Frank J J; van Laarhoven, Karel A; Wosten, Han; Dijksterhuis, Jan
2017-01-01
AIMS: To have a better understanding of fungal growth on gypsum building materials to prevent indoor fungal growth. METHODS AND RESULTS: Gypsum is acquired by mining or as a by-product of flue-gas desulfurization or treatment of phosphate ore for the production of fertilizer. Natural gypsum,
2. Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings
International Nuclear Information System (INIS)
2016-01-01
This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM. - Highlights: • New concept of incorporation of more than 1 type of PCM in plastering mortars (hybrid PCM). • Assessment of thermal performance of hybrid PCM plastering mortar. • Thermo-physical properties of plastering mortars modified with PCMs incorporation. • Experimental and numerical simulations of thermal behaviour on laboratory scale prototype.
3. Investigation of field temperature in moulds of foamed plaster
Directory of Open Access Journals (Sweden)
M. Pawlak
2007-12-01
Full Text Available Plaster moulds used in precision foundry are characterized by a very low permeability which, in the case of classic plaster moulds, equals to about 0,01÷0,02 m2/(MPa·s. One of the most effective methods for increasing the permeability is a foaming treatment. Another characteristic feature of plaster is its very good insulating power which has influence on the process of solidification and cooling of a cast and also on a knock-out property. This insulating power is a function of thermophysical properties of plaster which, in turn, depend mainly on the mineralogical composition of the mould material, its bulk density as well as on the temperature of the pouring alloy. In the case of a foamed plaster mould an increase of the degree of foaming increases its porosity which causes a change in its thermophysical properties, thereby increasing susceptibility of the mass to overheating. The susceptibility of the plaster layer surrounding the cast to overheating is favorable because it makes it easier to knock-out of the cast by immersing the hot mould in cold water. Thermal and phase tensions that are created during this process cause fast destruction of plaster. This paper describes our investigations aimed at the determination of the dependence of the mould temperature field on the time of the cast stay in the mould, as recorded in a process of an unsteady heat flow. The determined data were planned to be used for estimation of the technological properties of the plaster mould. The tests were carried out using the plaster α-Supraduro and Alkanol XC (foaming agent. The test mould had a diameter of Ø 120 mm with centrally situated mould cavity of Ø 30 mm. Plaster moulds with a degree of foaming 20; 32,5 and 45% and comparatively from non-foaming plaster were tested and their temperatures were measured at the distance x=2; 9; 21; 25;27; 30 mm from the mould cavity within 25 min. Analysis of the results leads to the conclusion, that the highest
4. Development of Latent Heat Storage Phase Change Material Containing Plaster
Directory of Open Access Journals (Sweden)
Diana BAJARE
2016-05-01
Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.
5. Dilatometric examination of moulds with plaster binder
Directory of Open Access Journals (Sweden)
2011-01-01
Full Text Available Investigations concerning thermal expansion of moulding materials with plaster binder have been performed for two mixture compositionsof Authors’ own design, as well as for the material used in jewellery industry under the Prima-Cast trade name, and for ThermoMold 1200moulding material. The results of dilatometric examinations of these materials, carried out within the temperature range from about 20°Cto 650°C by means of the DA-3 automatic dilatometer, have been compared. An analysis of this comparison has revealed that it is thematrix composition which is decisive for the magnitude of dimensional changes of moulds, and that applying components which do notexhibit polymorphic transformations reduces dimensional changes of a mould during its thermal treatment.
6. Effect of preparation variables of plaster molds for slip casting of sanitary ware
Directory of Open Access Journals (Sweden)
Rafael E. Ochoa
2017-11-01
Full Text Available A full factorial design was used to evaluate the effect of various preparation conditions for making plaster molds for slip casting of sanitary ware. We investigated the relationships between the processing conditions, microstructure, and final properties of the plaster molds. The results showed that the rheological behavior, and hence, the time during which the plaster suspension is pourable for making the plaster molds (before an important increase in viscosity due to the precipitation of gypsum crystals were dependent on the preparation conditions. Variations in the chemical composition, pore size distribution, and microstructure explained the statistically significant effect of preparation variables (including the mixing time, water temperature, and water quality. Preparation conditions that promoted high initial viscosity of the plaster suspension (accelerative effect of the setting time developed less porous structure in the mold that principally increased the compressive strength (16%, deionized water instead of tap water and the casting rate (9%, water at 25 °C instead of 38 °C. According to the results are proposed optimum conditions to make the molds while avoiding unnecessary energy use. Resumen: Mediante un diseño factorial completo se evaluaron diferentes condiciones de preparación de moldes de yeso para colado tradicional de muebles sanitarios. Se investigó la relación entre procesamiento, microestructura y propiedades del molde. Los resultados mostraron que el comportamiento reológico y por lo tanto el tiempo durante el cual la suspensión de yeso se puede verter para conformar los moldes (antes de un incremento importante de viscosidad debido a la formación de cristales de yeso fueron dependientes de las condiciones de preparación. Variaciones en composición química, distribución de tamaño de poro y microestructura explicaron el efecto estadísticamente significativo de las variables de preparación (que incluyeron
7. Investigation and dating of gypsum crystals from Sivrihisar region in Eskisehir by ESR and TL techniques
International Nuclear Information System (INIS)
2011-01-01
Gypsum crystals taken from Sivrihisar-Eskisehir district were investigated and dated by Electron Spin Resonance (ESR) and Thermoluminescence (TL) techniques. The natural ESR spectra of gypsum samples had also the signals of Mn 2 + in addition to the signal at g=2.009. It was observed that the intensity of ESR signal at g=2.009 increased with gamma irradiation dose. This ESR signal (g=2.009) was used as a dating signal in dating of gypsum samples. The only one TL peak at about 278 degree Celsius was observed in TL glow curves of nonirradiated gypsum sample. In the case of irradiated sample, TL peak at 157 degree Celsius was observed in addition of TL peak at 278 degree Celsius. Gypsum samples were irradiated with a 6 0Co gamma source. The ESR spectra and TL glow curve of gypsum samples were recorded by X-band ESR spectrometer and Risφ TL/OSL reader, respectively. For samples, ESR/TL dose-response curves was constructed. Dose-response curves were fitted with an exponential saturation function. Based on this model, accumulated dose (AD) values for dating are determined. 2 38U, 2 32Th and 4 0K analysis was carried out for gypsum crystals and dolomite which enveloped these gypsum crystals. The internal dose rate was calculated from 2 38U, 2 32Th and 4 0K analysis results of gypsum sample. The external dose rate was calculated by using 2 38U, 2 32Th and 4 0K analysis results of dolomite and cosmic dose rate. Internal and external gamma dose-rate was used for dating calculations. Because of successive recrystallization of gypsum sample after formation, calculated age values of gypsum is smaller than expected formation age.
8. Health economic evidence of 5% lidocaine medicated plaster in post-herpetic neuralgia
Directory of Open Access Journals (Sweden)
Liedgens H
2013-11-01
Full Text Available Hiltrud Liedgens,1 Marko Obradovic,1 Mark Nuijten2 1Grunenthal GmbH, Aachen, Germany; 2Ars Accessus Medica, Amsterdam, the Netherlands Background: Post-herpetic neuralgia (PHN is the most common and most debilitating complication of herpes zoster, and involves considerable associated costs. Objective: This paper presents results from nine health economic studies undertaken in eight European countries that compared lidocaine medicated plaster with gabapentin and/or pregabalin in PHN. It aims to support the increasing need for published cost-effectiveness data for health care decision-making processes in Europe. Methods: All studies were based on a similar core Markov model with data derived from clinical trials, local Delphi panels, and official national price and tariff lists. The main outcome measure was cost per quality-adjusted life year gained; time without pain or intolerable adverse events was also included as a secondary outcome measure. All studies focused on an elderly population of patients with PHN who had insufficient pain relief with standard analgesics and could not tolerate or had contraindications to tricyclic antidepressants. Results: Despite considerable differences in many of the variables used, the results showed remarkable similarity and suggested that use of lidocaine medicated plaster offered cost-savings in many of the countries studied, where it proved a highly cost-effective alternative to both gabapentin and pregabalin. Conclusion: Lidocaine medicated plaster is a cost-effective alternative to gabapentin and pregabalin in the treatment of PHN. These savings are largely the result of the superior safety profile of the lidocaine medicated plaster. Keywords: post-herpetic neuralgia, zoster, cost-effectiveness, lidocaine, plaster
9. Mineral potential of clays that cover the gypsum deposits in Araripina-PE region
International Nuclear Information System (INIS)
Lira, B.B.; Anjos, I.F. dos; Rego, S.A.B.C.
2011-01-01
In the present work the applicability of the clays that cover the deposits of Gypsum Plaster in the region of Araripina - PE for use as the ceramic pigments and for bricks production in the red ceramic industry was analyzed. The clay minerals contained the illite, kaolinite and smectite, with high proportion of the last one. The possibility of industrial application of this mineral clay is considerable; however, the mining industries that mine and process the gypsum in the region do not take the clays into account as the potential mineral. In general, industries use the clay minerals in manufacturing processes or as key raw materials, or as the alternatives for some kinds of the chemical processing industries. This paper aims to highlight the potential of materials that cover the deposits of gypsum in reference. The material sampled from different deposit layers was characterized and the physical treatment of ore was applied. The results showed that the material analyzed can be used in various kinds of industry, such as the production of natural ceramic pigments. (author)
10. Growth of indoor fungi on gypsum.
Science.gov (United States)
Segers, F J J; van Laarhoven, K A; Wösten, H A B; Dijksterhuis, J
2017-08-01
To have a better understanding of fungal growth on gypsum building materials to prevent indoor fungal growth. Gypsum is acquired by mining or as a by-product of flue-gas desulphurization or treatment of phosphate ore for the production of fertilizer. Natural gypsum, flue-gas gypsum and phosphogypsum therefore have different mineral compositions. Here, growth of fungi on these types of gypsum was assessed. Conidia of the indoor fungi Aspergillus niger, Cladosporium halotolerans and Penicillium rubens were inoculated and observed using microscopic techniques including low-temperature scanning electron microscopy. Elemental analysis of gypsum was done using inductively coupled plasma atomic emission spectroscopy and segmented flow analysis. Moisture content of the gypsum was determined using a dynamic vapour sorption apparatus. Aspergillus niger, C. halotolerans and P. rubens hardly germinated on natural gypsum and flue-gas gypsum. The latter two fungi did show germination, outgrowth, and conidiation on phosphogypsum, while A. niger hardly germinated on this substrate. Other experiments show that C. halotolerans and P. rubens can develop in pure water, but A. niger does not. The observations show that the lack of germination of three indoor fungi is explained by the low amount of phosphor in natural, flue-gas and laboratory-grade gypsum. Additionally, C. halotolerans and P. rubens can develop in pure water, while conidia of A. niger do not show any germination, which is explained by the need for organic molecules of this species to induce germination. Indoor fungal growth is a potential threat to human health and causes damage to building materials. This study possibly helps in the application of the right type of gypsum in buildings. © 2017 The Society for Applied Microbiology.
11. Effect of an admixture from Agave americana on the physical and mechanical properties of plaster
Directory of Open Access Journals (Sweden)
Ochoa, J. C.
2013-03-01
Full Text Available Physical and mechanical properties of a plaster paste added with an organic admixture, of the leaves of Agave americana, were studied. Plastic consistency behavior was evaluated and the water/gypsum(w/g ratio was determined for each dosage of the admixture. Admixtur eeffect on setting was evaluated too. The chemical transformation of the hemihydrated form to gypsum (dihydrated form was studied using a novel technique based on a moisture analyzer by halogen light. Flexural and compressive strengths were measured. The results show that ,for the same consistency, accordingly mechanical strengths were improved too. The setting times were increased which would enhance the application time of plaster and would reduce plastic shrinkage, common problems in this type of material. The changes in these physical properties not substantially affect the final mechanical strengths.
12. Attenuation characteristics of gypsum wallboard
International Nuclear Information System (INIS)
Christensen, Ralph C.; Sayeg, Joseph
1978-01-01
Increased cost of lead is promoting enhanced usage of common building materials for shielding in diagnostic medical and dental facilities where only a few half value layers (HVLs) are needed. We have measured attenuation of x-rays in gypsum wallboard as a function of kVp, filtration, and wallboard thickness. Our findings, obtained using a Victoreen 555 with an 0.1 DAS probe in poor geometry, are in agreement with the sparse data in the literature (Gross and McCullough (1977), Radiology 122: 825. Moos et al. (1961), Oral Surgery, Oral Medicine, and Oral Pathology 14: 569) but extend to thicker wall configurations and different kVp and filtration parameters. We conclude that gypsum wallboard as sole shielding material should be used with great caution. These findings are of value in maximizing the benefit/cost ratio for diagnostic shielding, and strengthen the conviction that, where used for shielding purposes, common building materials must be installed carefully and HVL-depth dependence considered thoroughly. (author)
13. Phases, periphases, and interphases equilibrium by molecular modeling. I. Mass equilibrium by the semianalytical stochastic perturbations method and application to a solution between (120) gypsum faces
Science.gov (United States)
Pedesseau, Laurent; Jouanna, Paul
2004-12-01
The SASP (semianalytical stochastic perturbations) method is an original mixed macro-nano-approach dedicated to the mass equilibrium of multispecies phases, periphases, and interphases. This general method, applied here to the reflexive relation Ck⇔μk between the concentrations Ck and the chemical potentials μk of k species within a fluid in equilibrium, leads to the distribution of the particles at the atomic scale. The macroaspects of the method, based on analytical Taylor's developments of chemical potentials, are intimately mixed with the nanoaspects of molecular mechanics computations on stochastically perturbed states. This numerical approach, directly linked to definitions, is universal by comparison with current approaches, DLVO Derjaguin-Landau-Verwey-Overbeek, grand canonical Monte Carlo, etc., without any restriction on the number of species, concentrations, or boundary conditions. The determination of the relation Ck⇔μk implies in fact two problems: a direct problem Ck⇒μk and an inverse problem μk⇒Ck. Validation of the method is demonstrated in case studies A and B which treat, respectively, a direct problem and an inverse problem within a free saturated gypsum solution. The flexibility of the method is illustrated in case study C dealing with an inverse problem within a solution interphase, confined between two (120) gypsum faces, remaining in connection with a reference solution. This last inverse problem leads to the mass equilibrium of ions and water molecules within a 3 Å thick gypsum interface. The major unexpected observation is the repulsion of SO42- ions towards the reference solution and the attraction of Ca2+ ions from the reference solution, the concentration being 50 times higher within the interphase as compared to the free solution. The SASP method is today the unique approach able to tackle the simulation of the number and distribution of ions plus water molecules in such extreme confined conditions. This result is of prime
14. Plasters and mortars with extremely high concentrations of radium in Joachimsthal
International Nuclear Information System (INIS)
Thomas, J.; Moucka, L.
1993-01-01
In 1898 Mme Curie used wastes from the uranium factory in Joachimsthal for separation of the new element, radium. This waste was unfortunately also used in plasters and mortars for restoration of houses after frequent fires and conflagrations in the past century. Concentrations of 100 kBq.kg -1 and gamma dose rates of 40 μGy.h -1 in contact with the wall are not rare events in these houses; but the wastes are usually not the worst sources of radon there. Results of measurements obtained in a house investigated in detail are evaluated and intercompared, using relations and models (dose rates, exhalation rates, radium and radon concentrations, air exchange rates). Basic remedy measure (knock off of plasters, removal of a vault and of filling under floors) are proposed, and a new measurement is required before providing definitive measures. (author). 2 refs, 4 figs, 3 tabs
15. Measurement of soil moisture using gypsum blocks
DEFF Research Database (Denmark)
Friis Dela, B.
the building. Consequently, measuring the moisture of the surrounding soil is of great importance for detecting the source of moisture in a building. Up till now, information has been needed to carry out individual calibrations for the different types of gypsum blocks available on the market and to account......For the past 50 years, gypsum blocks have been used to determine soil moisture content. This report describes a method for calibrating gypsum blocks for soil moisture measurements. Moisture conditions inside a building are strongly influenced by the moisture conditions in the soil surrounding...
16. Effects of gypsum on trace metals in soils and earthworms
Science.gov (United States)
Mined gypsum has been beneficially used for many years as an agricultural amendment. Currently a large amount of flue gas desulfurization (FGD) gypsum is produced by removal of SO2 from flue gas streams when fuels with high S content are burned. The FGD gypsum, similar to mined gypsum, can enhance c...
17. Corrosion of bare and galvanized steel in gypsum
Directory of Open Access Journals (Sweden)
Gómez, Mercedes
1988-12-01
Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.
18. Gypsum and hydrohalite dynamics in sea ice brines
Science.gov (United States)
Butler, Benjamin M.; Papadimitriou, Stathys; Day, Sarah J.; Kennedy, Hilary
2017-09-01
Mineral authigenesis from their dissolved sea salt matrix is an emergent feature of sea ice brines, fuelled by dramatic equilibrium solubility changes in the large sub-zero temperature range of this cryospheric system on the surface of high latitude oceans. The multi-electrolyte composition of seawater results in the potential for several minerals to precipitate in sea ice, each affecting the in-situ geochemical properties of the sea ice brine system, the habitat of sympagic biota. The solubility of two of these minerals, gypsum (CaSO4 ·2H2O) and hydrohalite (NaCl · 2H2O), was investigated in high ionic strength multi-electrolyte solutions at below-zero temperatures to examine their dissolution-precipitation dynamics in the sea ice brine system. The gypsum dynamics in sea ice were found to be highly dependent on the solubilities of mirabilite and hydrohalite between 0.2 and - 25.0 ° C. The hydrohalite solubility between - 14.3 and - 25.0 ° C exhibits a sharp change between undersaturated and supersaturated conditions, and, thus, distinct temperature fields of precipitation and dissolution in sea ice, with saturation occurring at - 22.9 ° C. The sharp changes in hydrohalite solubility at temperatures ⩽-22.9 °C result from the formation of an ice-hydrohalite aggregate, which alters the structural properties of brine inclusions in cold sea ice. Favourable conditions for gypsum precipitation in sea ice were determined to occur in the region of hydrohalite precipitation below - 22.9 ° C and in conditions of metastable mirabilite supersaturation above - 22.9 ° C (investigated at - 7.1 and - 8.2 ° C here) but gypsum is unlikely to persist once mirabilite forms at these warmer (>-22.9 °C) temperatures. The dynamics of hydrohalite in sea ice brines based on its experimental solubility were consistent with that derived from thermodynamic modelling (FREZCHEM code) but the gypsum dynamics derived from the code were inconsistent with that indicated by its
19. Gypsum ground: a new occurrence of gypsum sediment in playas of central Australia
Science.gov (United States)
Xiang Yang Chen; Bowler, James M.; Magee, John W.
1991-06-01
There are many playas (dry salt lakes) in arid central Australia (regional rainfall about 250 mm/y and pan evaporation around 3000 mm/y). Highly soluble salts, such as halite, only appear as a thin (several centimetres thick), white, ephemeral efflorescent crust on the dry surface. Gypsum is the major evaporite precipitating both at present and preserved in sediment sequences. One type of gypsum deposit forms a distinctive surface feature, which is here termed "gypsum ground". It consists of a thick (up to 80 cm) gypsum zone which rises from the surrounding smooth white playa surface and is overlain by a heaved brown crust. The gypsum zone, with an average gypsum content above 60%, consists of pure gypsum sublayers and interlayered clastic bands of sandy clay. The gypsum crystals are highly corroded, especially in the direction parallel to the c-axis and on the upper sides where illuviated clay has accumulated in corrosion hollows. Overgrowth parallel to the a- and b-axes is very common, forming highly discoidal habits. These secondary changes (corrosion and overgrowth) are well-developed in the vadose zone and absent from crystals below the long-term watertable (depth around 40 cm). These crystal characteristics indicate a rainwater leaching process. At Lake Amadeus, one of the largest playas (800 km 2) of central Australia, such gypsum ground occupies 16% of the total area. The gypsum ground is interpreted as an alteration of a pre-existing gypsum deposit which probably extended across the whole playa before breaking down, leaving a playa marginal terrace and several terrace islands within the gypsum ground. This pre-existing gypsum deposit, preserved in the residual islands, consists of pure, pale, sand-sized lenticular crystals. It is believed to have been deposited during an episode of high regional watertable, causing active groundwater seepage and more frequent surface brine in the playa. A later fall in watertable, probably resulting from climatic change
20. Production of polymer-plaster composite by gamma irradiation
International Nuclear Information System (INIS)
Gazineu, Maria Helena Paranhos; Santos, Valdemir Alexandre dos; Dantas, Carlos Costa
2009-01-01
The estimated amount of plaster wastes in the construction industry is 45%. The reduction of this waste is of concern, because the cost of lost material and the waste management can affect the competitiveness of the company. The mixture of plaster with a particular resin generates a composite, which gives the pre-molded obtained from this mixture, special properties. In this case, the plasticity of the plaster generates pre-molded products with wealth of details. Additionally, the use of nuclear techniques for the initiation of polymerization reaction for obtaining this type of composite can eliminate the need for a heat source which is the conventional way to obtain polymerization, considerably reducing the costs of the process. As a function of the availability and the cost of styrene monomer, in the initial phase of the research test samples were prepared from plaster composites with this type of material. The test samples, composed of plaster and styrene, were irradiated in the presence of a Cs-137 (662 keV) gamma source for a period of time of two days in an air pressurized chamber. Tests of resistance to compression, tensile strength in bending and water absorption, were based on a type of experimental design, CCRD (Central Composite Rotatable Design). The percent average weight of polymer by weight of the test sample was 14.0%. The presence of a polymerized resin gives the sample qualities such as being highly impervious to water and high mechanical strength, allowing its use in the manufacture of different types of materials. (author)
1. Design of Cold-Formed Steel Screw Connections with Gypsum Sheathing at Ambient and Elevated Temperatures
Directory of Open Access Journals (Sweden)
Wei Chen
2016-09-01
Full Text Available Load-bearing cold-formed steel (CFS walls sheathed with double layers of gypsum plasterboard on both sides have demonstrated good fire resistance and attracted increasing interest for use in mid-rise CFS structures. As the main connection method, screw connections between CFS and gypsum sheathing play an important role in both the structural design and fire resistance of this wall system. However, studies on the mechanical behavior of screw connections with double-layer gypsum sheathing are still limited. In this study, 200 monotonic tests of screw connections with single- or double-layer gypsum sheathing at both ambient and elevated temperatures were conducted. The failure of screw connections with double-layer gypsum sheathing in shear was different from that of single-layer gypsum sheathing connections at ambient temperature, and it could be described as the breaking of the loaded sheathing edge combined with significant screw tilting and the loaded sheathing edge flexing fracture. However, the screw tilting and flexing fracture of the loaded sheathing edge gradually disappear at elevated temperatures. In addition, the influence of the loaded edge distance, double-layer sheathing and elevated temperatures is discussed in detail with clear conclusions. A unified design formula for the shear strength of screw connections with gypsum sheathing is proposed for ambient and elevated temperatures with adequate accuracy. A simplified load–displacement model with the post-peak branch is developed to evaluate the load–displacement response of screw connections with gypsum sheathing at ambient and elevated temperatures.
2. GYPSUM DEPOSITS IN THE REPUBLIC OF CROATIA
Directory of Open Access Journals (Sweden)
Anto Gabrić
2002-12-01
Full Text Available The occurences and deposits of gypsum can be found in big karst poljes (Sinjsko, Vrličko, Petrovo, Kosovo and Kninsko as well as in tectonnically predestined river valleys of Zrmanja, Butišnica and Una. There also appear spatially localized occurences on the island of Vis and in the vicinity of Samobor. Evaporites (gypsum and anhydrite with adjoining overlying clastic rocks (red sandstones, siltites and pelites, carbonate rocks (dolomites and limestones and porous carbonate breccias (Rauhwackes were deposited during the period of Upper Permian. The recent position of the Upper Permian beds is a result of complex tectonic, particularly neotectonic, movements and diapiric displacements. Evaporites were deposited in marginal areas of the epicontinental marine basin, in a period of favourable conditions for the sabkha and playa sedimentation due to the continuous shoreline progradation. The Upper Permian age of these sediments in Dalmatio is proved by the characteristic mineral paragenesis and palinological determinations in elastics rocks, as well as by isotope analyses of sulphure in gypsum. Gypsum is a significant ore mineral resource in building, cement production, as well as in a number of tehnological processes used in chemical industry and elsewhere. According to the recent investigations gypsum is predestined to serve as an ore mineral resource of significant perspectives (the paper is published in Croatian.
3. Gypsum karst in Italy: a review
Science.gov (United States)
De Waele, Jo; Chiarini, Veronica; Columbu, Andrea; D'Angeli, Ilenia M.; Madonia, Giuliana; Parise, Mario; Piccini, Leonardo; Vattano, Marco; Vigna, Bartolomeo; Zini, Luca; Forti, Paolo
2016-04-01
Although outcropping only rarely in Italy, gypsum karst has been described in detail since the early XXth century (Marinelli, 1917). Gypsum caves are now known from almost all Italian regions (Madonia & Forti, 2003), but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche regions), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum quarries in Piedmont (Vigna et al., 2010). During the late 80s and 90s several multidisciplinary studies have been carried out in many gypsum areas. All this work converged into a comprehensive overview in 2003 (Madonia & Forti, 2003). Further detailed studies focused on the gypsum areas of Emilia Romagna (Chiesi et al., 2010; Forti & Lucci, 2010; Demaria et al., 2012; De Waele & Pasini, 2013; Ercolani et al., 2013; Columbu et al., 2015; Lucci & Piastra, 2015; Tedeschi et al., 2015) and of Sicily (Madonia & Vattano, 2011). Sinkholes related to Permo-Triassic gypsum have been studied in Friuli Venezia Giulia (Zini et al., 2015). This presentation will review the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results. References Chiesi M., et al. (2010) - Origin and evolution of a salty gypsum/anhydrite karst spring: the case of Poiano (Northern Apennines, Italy). Hydrogeology Journal, 18, pp. 1111-1124. Columbu A. et al. (2015) - Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region. Geology, 43(6), 539-542. Demaria D. et al. (Eds.) (2012), Le Grotte Bolognesi, GSB-USB, 431 p. De Waele J., Pasini G. (2013) - Intra-messinian gypsum palaeokarst in the northern Apennines and its palaeogeographic implications. Terra Nova 25, pp. 199-205. Ercolani M., et al. (Eds.) (2013), I Gessi e la Cave i Monte Tondo. Studio multidisciplinare di un'area carsica nella Vena del Gesso Romagnola. Memorie Ist. It. Spel. II(26), 559 p
4. Mechanical properties of gypsum board at elevated temperatures
Science.gov (United States)
S.M. Cramer; O.M. Friday; R.H. White; G. Sriprutkiat
2003-01-01
Gypsum board is a common fire barrier used in house and general building construction. Recently, evaluation of the collapses of the World Trade Center Towers highlighted the potential role and failure of gypsum board in containing the fires and resisting damage. The use of gypsum board as primary fire protection of light-flame wood or steel construction is ubiquitous....
5. [Conservative treatment of cervical radiculopathy with 5% lidocaine medicated plaster].
Science.gov (United States)
Mattozzi, I
2015-02-01
Cervical radiculopathy is a mixed pain syndrome characterized by neuropathic, skeletal and myofascial pain. This condition is frequently found in developed countries and is a significant source of disability and a reason for frequent medical consultation. In our Pain Therapy Centre, cervical radiculopathy is initially treated with bi-weekly cycles of mesotherapy coupled, at least 15 days later, with physiotherapy to reach the complete mobilization of cervical spine. Cervical radiculopathy is a localized neuro-pathic pain and in agreement with international guidelines, we checked if patients treated topically with 5% lidocaine medicated plaster may benefit in improving pain management and in reducing the time necessary to start physiotherapy. A retrospective study was carried out on 60 patients, of which 30 were treated with mesotherapy and 30 were treated with 5% lidocaine medicated plaster. Data for a total of 30 days observation were collected from the patient medical records. In particular, besides medical history, intensity of pain, intensity of allodynia and pain were considered. For all analyzed parameters, both treatments were effective, but patients treated with 5% lidocaine medicated plaster showed faster control of the painful symptoms, an essential condition for an earlier rehabilitative treatment.
6. CFD analysis of a rotary kiln using for plaster production and discussion of the effects of flue gas recirculation application
Science.gov (United States)
Gürtürk, Mert; Oztop, Hakan F.; Pambudi, Nugroho Agung
2018-04-01
In this study, the CFD analysis of the rotary kiln is carried out for examining effects of various parameters on energy consumption and efficiency of the rotary kiln. The flue gas recirculation using in many applications is a useful method for combusting of fuel unburned in the flue gas. Also, effects of flue gas recirculation on the combusting of fuel, operating temperature and efficiency of the rotary kiln are discussed in this study. The rotary kiln, which is considered in this study, is used in plaster plant. Two different CFD models were created and these models are compared according to many parameters such as temperature distribution, mixture fraction, the mass fraction of O2, CO, CO and CH4 in the combustion chamber. It is found that the plaster plant has a great potential for an increase in energy efficiency. Results obtained for producers of rotary kiln and burner will be useful for determining better design parameters.
7. Physical and mechanical characterization of gypsum boards containing phase change materials for latent heat storage
Directory of Open Access Journals (Sweden)
Oliver-Ramírez, A.
2011-09-01
Full Text Available This article describes the design and manufacture of a gypsum board which, despite its 45 % wt content of phase change materials, meets the minimum physical and mechanical requirements laid down in the legislation on gypsum plasters (Spanish and European standard UNE EN 13279 and Spanish specifications for gypsum acceptance, RY 85. Under this design, a one-metre square, 1.5-cm thick board contains 4.75 kg of PCM, much more than in any prior drylining (the maximum attained to date is 3 kg per m2. The mechanical and physical characteristics of this new composite were previously improved with two joint-action additives: polypropylene fibres and melamine formaldehyde as a dispersing agent. In the 20-30 ºC temperature range, a gypsum board 1.5 cm thick containing this percentage of PCMs can store five times more thermal energy than conventional plasterboard of the same thickness, and the same amount of energy as half-foot hollow brick masonry.
En esta investigación se ha diseñado y fabricado un panel de escayola que incorpora un 45% en peso de material de cambio de fase, manteniendo las propiedades físicas y mecánicas exigidas en la normativa de aplicación para yesos de construcción (UNE EN 13279 y referencias a la RY 85. Así, un panel de 1,0 m2 y 1,5 cm de espesor, contiene 4,75 kg de PCM, cantidad muy superior a la conseguida hasta la fecha (3 kg/m2. Para ello se ha mejorado previamente sus prestaciones mecánicas y físicas mediante adiciones binarias: fibras de polipropileno y dispersión de melanina formaldehído. Este porcentaje es capaz de almacenar en 1,5 cm de espesor cinco veces la energía térmica de un panel de cartón yeso con el mismo espesor y la misma cantidad que una fábrica de 1/2 pie de ladrillo hueco, en el rango de temperaturas próximas a la de confort (20-30 ºC.
8. Plaster: its influence on the behaviour of mould surface in the gluing process
International Nuclear Information System (INIS)
Jordao, M.A.P.; Goulart, E.P.; Souza, D.D.D. de; Kiyohara, P.K.
1989-01-01
Plaster is an important auxiliary raw material in ceramics, but the industry in Brazil use to give litle importance to its properties. The IPT Ceramic Department initiated studies to upgrade local knowledge on this material. In this paper, the following already studied topics are presented. Characterization of α and β plaster powder, by X-ray diffraction, optical and scanning electron microscopy, specific gravity and surface are (BET). Influence of the plaster/water ratio on the mould characteristics by X-ray diffraction, scanning electron microscopy, porosity and permeability. Behavior of the plaster mould surface against the moulded surface after several aluminum oxide splip castings by scanning electron microscopy [pt
9. PCM-enhanced lime plasters for vernacular and contemporary architecture
Science.gov (United States)
Theodoridou, Magdalini; Kyriakou, Loucas; Ioannou, Ioannis
2016-04-01
In 1997, the European Union (EU) pledged to reduce the amount of greenhouse gas emissions by 20% below the levels of 1990 by the end of 2020. In recent years it has become evident that, in order to reach that goal, EU Member States must take measures to encourage sustainability in the building industry, which is a major energy consumer. Such measures should involve the use of innovative, environmentally friendly materials and methods in new constructions, as well as the renovation of existing properties by upgrading their current state of energy efficiency. Phase Change Materials (PCMs) have the ability to absorb and release thermal energy, in the form of latent heat, during the melting or solidifying processes respectively. Thus, they may be used as additives in the production of thermally efficient composite building materials. A PCM-enhanced plaster is a heat storage medium combining an appropriate PCM with a cementitious or non-cementitious matrix to produce a low-cost thermal storage material with structural and thermostatic properties. Although innovative technologies, such as PCMs, have certainly contributed to the boost in the evolution of the building materials industry in recent years, a significant proportion of these technologies and practices have not yet been fully exploited in materials based on traditional principles. This paper focuses on the design and production of novel cementless PCM-enhanced lime plasters, in line with the traditional production technology of lime composites. The new plasters are produced using either hydrated or natural hydraulic lime binder, crushed calcarenite sand (0-2 mm) and commercial microencapsulated PCM in powder form (5% w/w of solids). Results from comparative tests between reference mixtures and mixtures with the addition of PCM, carried out 28, 56 and 90 days after laboratory production, prove the potential of PCMs in enhancing the thermal performance of traditional lime-based composites. The modified composites
10. Effect of paint on vapour resistivity in plaster
Directory of Open Access Journals (Sweden)
de Villanueva, L.
2008-12-01
11. Tunisian gypsums: Characteristics and use in cement
Science.gov (United States)
Mahmoudi, Salah; Bennour, Ali; Chalwati, Youssef; Souidi, Khouloud; Thabet, Manel; Srasra, Ezzedine; Zargouni, Fouad
2016-09-01
Gypsum materials of hundred meters thickness and interbedded with marine claystones and limestones from different paleogeographic sectors in the Tunisian territory are studied to assess their suitability for cement production. For this reason, thirty representative samples are analysed by chemical, physical and geotechnical tests. The obtained results for the studied gypsum materials are compared to Tunisian and European norms and with the local cements, currently marketed and which obey international norms. Indeed, for all samples hydraulic modulus HM, silica modulus SM and alumina modulus AM vary from (2.37-2.44), (2.48-2.68) and (1.45-2.5), respectively; whereas the required values for these modulus are (1.5-2.5), (2-3) and (1.5-2.5). The same behavior is observed for mineralogical analyses of C3S, C2S, C3A and C4AF and compressive strength at different ages. Briefly, Tunisia contains important reserves of gypsum scattered and spread over the Tunisian territory and can be used for cement production.
12. Lightened plaster: alternative solutions to cellular solids addition
Directory of Open Access Journals (Sweden)
Del Río, M.
2004-09-01
Full Text Available The following paper pretends to analyze different processes in order to lightweighters gypsum as an alternative way at the cellular fillers addition, in order to establish the most suitable ones for the manufacture of plasterboard. Outstanding the process which uses foamings addition to lighten gypsum uses nowdays only to manufacture cellular concrete.
En este artículo se presenta el análisis de diferentes procedimientos para aligerar la escayola, como alternativas a la adición de sólidos celulares, determinando los más adecuados para la realización de prefabricados. Dentro de estos procedimientos cabe destacar la adición de espumantes, hasta ahora sólo utilizados para la fabricación de hormigones celulares.
13. Effect of shelf life on compressive strength of type iv gypsum
Science.gov (United States)
Kusumastuti, K. S.; Irawan, B.; Damiyanti, M.
2017-08-01
Type IV gypsum, as a dental material for an indirect restoration’s working model, should have strength and abrasive-resistant properties. These properties depend on the product’s shelf life and its proper storage, which sometimes are easily missed by sellers. The aim of this research was to observe the effect of shelf life on the compressive strength of type IV gypsum with different production dates. Twenty cylindrical specimens were separated into two groups with different production dates and tested with a universal testing with the crosshead speed of 1 mm per minute and a load of 2,500 kgf. The data were analyzed with independent t-tests. There was a significant difference (p<0.05) in the compressive strength between the two groups with an increase in compressive strength seen in the gypsum that was stored longer.
14. Competition between reaction-induced expansion and creep compaction during gypsum formation: Experimental and numerical investigation
Science.gov (United States)
Skarbek, R. M.; Savage, H. M.; Spiegelman, M. W.; Kelemen, P. B.; Yancopoulos, D.
2017-12-01
Deformation and cracking caused by reaction-driven volume increase is an important process in many geological settings, however the conditions controlling these processes are poorly understood. The interaction of rocks with reactive fluids can change permeability and reactive surface area, leading to a large variety of feedbacks. Gypsum is an ideal material to study these processes. It forms rapidly at room temperature via bassanite hydration, and is commonly used as an analogue for rocks in high-temperature, high-pressure conditions. We conducted uniaxial strain experiments to study the effects of applied axial load on deformation and fluid flow during the formation of gypsum from bassanite. While hydration of bassanite to gypsum involves a solid volume increase, gypsum exhibits significant creep compaction when in contact with water. These two volume changing processes occur simultaneously during fluid flow through bassanite. We cold-pressed bassanite powder to form cylinders 2.5 cm in height and 1.2 cm in diameter. Samples were compressed with a static axial load of 0.01 to 4 MPa. Water infiltrated initially unsaturated samples through the bottom face and the height of the samples was recorded as a measure of the total volume change. We also performed experiments on pure gypsum samples to constrain the amount of creep observed in tests on bassanite hydration. At axial loads 1 MPa, creep in the gypsum dominates and samples exhibit monotonic compaction. At intermediate loads, samples exhibit alternating phases of compaction and expansion due to the interplay of the two volume changing processes. We observed a change from net compaction to net expansion at an axial load of 0.250 MPa. We explain this behavior with a simple model that predicts the strain evolution, but does not take fluid flow into account. We also implement a 1D poro-visco-elastic model of the imbibition process that includes the reaction and gypsum creep. We use the results of these models, with
15. Reaction mechanism of reductive decomposition of FGD gypsum with anthracite
International Nuclear Information System (INIS)
Zheng, Da; Lu, Hailin; Sun, Xiuyun; Liu, Xiaodong; Han, Weiqing; Wang, Lianjun
2013-01-01
Highlights: • The reaction mechanism was different if the molar ratio of C/CaSO 4 was different. • The yield of CaO rises with an increase in temperature. • The optimal ratio of C/CaSO 4 = 1.2:1. • The decomposition process is mainly apparent solid–solid reaction with liquid-phase involved. - Abstract: The process of decomposition reaction between flue gas desulfurization (FGD) gypsum and anthracite is complex, which depends on the reaction conditions and atmosphere. In this study, thermogravimetric analysis with Fourier transform infrared spectroscopy (TGA-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and the experiment in a tubular reactor were used to characterize the decomposition reaction in a nitrogen atmosphere under different conditions. The reaction mechanism analysis showed that the decomposition reaction process and mechanism were different when the molar proportion of C/CaSO 4 was changed. The experiment results showed that appropriate increase in the C/CaSO 4 proportion and higher temperatures were suitable for the formation of the main production of CaO, which can help us to understand the solid state reaction mechanism better. Via kinetic analysis of the reaction between anthracite and FGD gypsum under the optimal molar ratio of C/CaSO 4 , the mechanism model of the reaction was confirmed and the decomposition process was a two-step reaction which was in accordance with apparent solid–solid reaction
16. Venous thromboembolism during hip plaster cast immobilisation: review of the literature
NARCIS (Netherlands)
Struijk-Mulder, M. C.; Ettema, H. B.; Heyne, R. A. J.; Rondhuis, J. J.; Büller, H. R.; Verheyen, C. C. P. M.
2014-01-01
There is a paucity of data regarding the risk of deep vein thrombosis during hip plaster cast immobilisation. The purpose of this article was to review the available evidence regarding the incidence of symptomatic venous thromboembolism (VTE) during hip plaster cast immobilisation. All papers
Science.gov (United States)
Wolfe, George
Papier-mache, plaster, and foam are inexpensive and versatile media for 3-dimensional classroom and studio art experiences. They can be used equally well by elementary, high school, or college students. Each medium has its own characteristic. Papier-mache is pliable but dries into a hard, firm surface that can be waterproofed. Plaster can be…
18. Simulating the structure of gypsum composites using pulverized basalt waste
Directory of Open Access Journals (Sweden)
Buryanov Аleksandr
2017-01-01
Full Text Available This paper examines the possibility of simulating the structure of gypsum composite modified with basalt dust waste to make materials and products based on it. Structural simulating of the topological space in gypsum modified composite by optimizing its grain-size composition highly improves its physical and mechanical properties. Strength and density tests have confirmed the results of the simulation. The properties of modified gypsum materials are improved by obtaining of denser particle packing in the presence of hemihydrate of finely dispersed basalt and plasticizer particles in the system, and by engaging basalt waste in the structuring process of modified gypsum stone.
19. Seepage Analysis of Upper Gotvand Dam Concerning Gypsum Karstification (2D and 3D Approaches)
DEFF Research Database (Denmark)
Sadrekarimi, Jamshid; Kiyani, Majid; Fakhri, Behnam
2011-01-01
Upper Gotvand Dam is constructed on the Karun River at the south west of Iran. In this paper, 2D and 3D models of the dam together with the foundation and abutments were established, and several seepage analyses were carried out. Then, the gypsum veins that are scattered throughout the foundation...
20. Efficiency of sulfuric acid, mined gypsum, and two gypsum by-products in soil crusting prevention and sodic soil reclamation
Energy Technology Data Exchange (ETDEWEB)
Amezketa, E.; Aragues, R.; Gazol, R. [Gobierno Navarra, Pamplona (Spain). Agricultural Resources Evaluation Center
2005-06-01
We evaluated the efficiency of four amendments (sulfuric acid, mined-gypsum, and the by-products coal-gypsum and lacto-gypsum) in crusting prevention of two calcareous nonsodic and sodic soils and in sodic soil reclamation. Treatments for crust prevention consisted of surface-applied amendments at equivalent rates of 5 Mg pure-gypsum ha{sup -1}. Treatments for sodic soil reclamation consisted of surface-applied acid and soil-incorporated gypsums at rates of 1 pure-gypsum requirement. The efficiency of these amendments was evaluated by comparing the final infiltration rates (FIR) of the amended vs. the nonamended soils measured in disturbed-soil columns pounded with low-salinity irrigation water. Electrical conductivity (EC) and Na in the leachates of the sodic soil were measured. In the crusting prevention experiment, FIRs (mm h{sup -1) of the nonsodic soil were 21 (nonamended), 33 to 35 (gypsum materials), and 53 (sulfuric acid), whereas those for the sodic soil were 0 (nonamended), 9 (lacto-gypsum), 15 to 17 (coal- and mined-gypsum), and 21 (sulfuric acid). In the sodic-soil reclamation experiment, FIRs were 0 (nonamended), 8 to 9 (gypsum-materials), and 17 (sulfuric acid) mm h{sup -1}. All amendments were effective in crusting prevention and soil reclamation, but sulfuric acid was the most efficient due to the fastest EC and Na reductions in the leachates. The three gypsum-materials were equally effective in the reclamation process and in the nonsodic soil crusting-prevention, whereas lacto-gypsum was less efficient in the sodic-soil crusting-prevention.
1. The influence of the pore structure on the moisture transport in lime plaster-brick systems as studied by NMR
NARCIS (Netherlands)
Nunes, C.; Pel, L.; Kunecký, J.; Slížková, Z.
2017-01-01
This paper presents an experimental analysis of the porous structure and drying kinetics of lime-based plasters and plaster-brick systems using different methods. The effect of adding a water-repellent admixture (linseed oil) to the plasters was also evaluated. Nuclear Magnetic Resonance (NMR) was
2. Flue gas desulfurization gypsum and fly ash
International Nuclear Information System (INIS)
1992-05-01
The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority's newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned for all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective
3. Soil management and application of agricultural gypsum in a Planosol for soybean cultivation
OpenAIRE
Marchesan, Enio; Tonetto, Felipe; Teló, Gustavo Mack; Coelho, Lucas Lopes; Aramburu, Bruno Behenck; Trivisiol, Vinicius Severo
2017-01-01
ABSTRACT: This study investigated the effects of soil management systems, tillage, and application of gypsum agricultural to soil, on soybean development in lowland areas. The experiment was carried out on an Alfisol in a randomized complete block design in a factorial arrangement. The two soil tillage practices were without deep tillage and with deep tillage. Gypsum treatments were no gypsum application, 500kg of gypsum ha-1, 1000kg of gypsum ha-1, and 1500kg of gypsum ha-1. Deep tillage res...
4. MARKETING OF BYPRODUCT GYPSUM FROM FLUE GAS DESULFURIZATION
Science.gov (United States)
The report gives results of an evaluation of the 1985 marketing potential of byproduct gypsum from utility flue gas desulfurization (FGD), for the area east of the Rocky Mountains, using the calculated gypsum production rates of 14 selected power plants. The 114 cement plants and...
5. Mechanical, Hygric and Thermal Properties of Flue Gas Desulfurization Gypsum
Directory of Open Access Journals (Sweden)
P. Tesárek
2004-01-01
Full Text Available The reference measurements of basic mechanical, thermal and hygric parameters of hardened flue gas desulfurization gypsum are carried out. Moisture diffusivity, water vapor diffusion coefficient, thermal conductivity, volumetric heat capacity and linear thermal expansion coefficient are determined with the primary aim of comparison with data obtained for various types of modified gypsum in the future.
6. Occurrence and geochemistry of Nafada Gypsum, north-eastern ...
African Journals Online (AJOL)
Gypsum deposits occur in numerous locations within the Senonian Fika Shale at Nafada, northeastern Nigeria. Geologic investigations at Baro Winde and Wuro Dabo mines indicate the occurrence of three varieties of gypsum namely, Balatino laminated, Alabaster and Satin Spar. These are interlayered within shale and ...
7. Gypsum as a bedding source for broiler chickens
Science.gov (United States)
Three trials examined the feasibility of flue gas desulfurization gypsum as a bedding material for raising broilers. Gypsum was used alone, under or on top of pine shavings and pine bark. Test materials were placed as bedding in pens to simulate commercial broiler production through three growout cy...
8. Hydrogen sulfide release from dairy manure storages containing gypsum bedding
Science.gov (United States)
Recycled gypsum products can provide a cost-effective bedding alternative for dairy producers. Manufacturers report reduced odors, moisture and bacteria in the stall environment when compared to traditional bedding. Gypsum provides a sulfate source that can be converted to hydrogen sulfide under ana...
9. Gypsum-anhydrites in 2 Ga Vempalle Formation, Cuddapah basin ...
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In fact high solubility in water leads to removal of gypsum in suficial environment. ... with presence of evaporite gypsum in the upper as well as lower part of the ..... created with shallow inlet or a slightly permeable seal with main water body.
10. Gypsum plasterboards enhanced with phase change materials: A fire safety assessment using experimental and computational techniques
Directory of Open Access Journals (Sweden)
Kolaitis Dionysios I.
2013-11-01
Full Text Available Phase Change Materials (PCM can be used for thermal energy storage, aiming to enhance building energy efficiency. Recently, gypsum plasterboards with incorporated paraffin-based PCM blends have become commercially available. In the high temperature environment developed during a fire, the paraffins, which exhibit relatively low boiling points, may evaporate and, escaping through the gypsum plasterboard's porous structure, emerge to the fire region, where they may ignite, thus adversely affecting the fire resistance characteristics of the building. Aiming to assess the fire safety behaviour of such building materials, an extensive experimental and computational analysis is performed. The fire behaviour and the main thermo-physical physical properties of PCM-enhanced gypsum plasterboards are investigated, using a variety of standard tests and devices (Scanning Electron Microscopy, Thermo Gravimetric Analysis, Cone Calorimeter. The obtained results are used to develop a dedicated numerical model, which is implemented in a CFD code. CFD simulations are validated using measurements obtained in a cone calorimeter. In addition, the CFD code is used to simulate an ISO 9705 room exposed to fire conditions, demonstrating that PCM addition may indeed adversely affect the fire safety of a gypsum plasterboard clad building.
11. The Effect of Aloe, Gelfoam, Plaster on Bone Formation in applying to the bone defect
International Nuclear Information System (INIS)
Choi, Eui Hwan; Kim, Su Gwan
1999-01-01
This study was to evaluate the effects of Aloe, Gelfoam, and Plaster of Paris on bone healing. Four experimental defects were created for placement of the three materials in the right femur of dogs. One defect served as an empty control site. The evaluation was performed at 1-, 6-, and 12-weeks by light microscopy and NIH image program. Radiographic and Histologic examinations showed new bone formation in the presence of Aloe, Gelfoam, and Plaster of Paris and similar bone healing reactions. On the basis of these findings, it was concluded that Aloe, Gelfoam, and Plaster of Paris may be adequate agents for use in bone procurement.
12. Permeability of gypsum samples dehydrated in air
Science.gov (United States)
Milsch, Harald; Priegnitz, Mike; Blöcher, Guido
2011-09-01
We report on changes in rock permeability induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air (dry) for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the reaction kinetics, so induced changes in porosity, and the concurrent evolution of sample permeability were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate and complete dehydration to anhydrite regardless of temperature. Porosity showed to continuously increase with reaction progress from approximately 2% to 30%, whilst the initial bulk volume remained unchanged. Within these limits permeability significantly increased with porosity by almost three orders of magnitude from approximately 7 × 10-19 m2 to 3 × 10-16 m2. We show that - when mechanical and hydraulic feedbacks can be excluded - permeability, reaction progress, and porosity are related unequivocally.
13. Measuring the gypsum content of C&D debris fines.
Science.gov (United States)
Musson, Stephen E; Xu, Qiyong; Townsend, Timothy G
2008-11-01
Construction and demolition (C&D) debris recycling facilities often produce a screened material intended for use as alternative daily cover (ADC) at active landfills or for shaping and grading at closed landfills. This product contains soil and small pieces of wood, concrete, gypsum drywall, shingles and other components of C&D debris. Concerns have been raised over the contribution of gypsum drywall in C&D debris fines to odor problems at landfills where the product is used. To address such concerns, limitations may be placed on the percentage of gypsum (or sulfate) that can occur, and standardized testing procedures are required to permit valid compliance testing. A test procedure was developed for measuring the gypsum content in C&D debris fines. The concentration of sulfate leached in an aqueous solution was used to estimate the initial gypsum content of the sample. The impact of sample size and leaching time were evaluated. Precision and accuracy increased with increasing gypsum content. Results from replicate samples had an average relative standard deviation of 9%. The gypsum content of fines obtained from different facilities in the US varied widely from 1% to over 25%. These variations not only occurred between differing facilities, but within batches produced within a single facility.
14. Impact of welan gum on tricalcium aluminate–gypsum hydration
International Nuclear Information System (INIS)
Ma Lei; Zhao Qinglin; Yao Chukang; Zhou Mingkai
2012-01-01
The retarding effect of welan gum on tricalcium aluminate–gypsum hydration, as a partial system of ordinary Portland cement (OPC) hydration, was investigated with several methods. The tricalcium aluminate–gypsum hydration behavior in the presence or absence of welan gum was researched by field emission gun scanning electron microscopy, X-ray diffraction and zeta potential analysis. Meanwhile, we studied the surface electrochemical properties and adsorption characteristics of welan gum by utilizing a zeta potential analyzer and UV–VIS absorption spectrophotometer. By adding welan gum, the morphology change of ettringite and retardation of hydration stages in tricalcium aluminate–gypsum system was observed. Moreover, we detected the adsorption behavior and zeta potential inversion of tricalcium aluminate and ettringite, as well as a rapid decrease in the zeta potential of tricalcium aluminate–gypsum system. The reduction on nucleation rate of ettringite and hydration activity of C 3 A was also demonstrated. Thus, through the adsorption effect, welan gum induces a retarding behavior in tricalcium aluminate–gypsum hydration. Highlights: ► Adsorption characteristics of welan gum on C 3 A and ettringite have been studied. ► C 3 A–gypsum hydration behavior and the hydration products are examined in L/S = 3. ► Welan gum retards the process of C 3 A–gypsum hydration. ► The addition of welan gum changes the nucleation growth of ettringite.
15. Interaction of gypsum with lead in aqueous solutions
International Nuclear Information System (INIS)
Astilleros, J.M.; Godelitsas, A.; Rodriguez-Blanco, J.D.; Fernandez-Diaz, L.; Prieto, M.; Lagoyannis, A.; Harissopulos, S.
2010-01-01
Sorption processes on mineral surfaces are a critical factor in controlling the distribution and accumulation of potentially harmful metals in the environment. This work investigates the effectiveness of gypsum (CaSO 4 .2H 2 O) to sequester Pb. The interaction of gypsum fragments with Pb-bearing solutions (10, 100 and 1000 mg/L) was monitored by performing macroscopic batch-type experiments conducted at room temperature. The aqueous phase composition was periodically determined by Atomic Absorption Spectrometry (AAS), Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Regardless of the [Pb aq ] initial , a [Pb aq ] final aq ] initial ≥ 100 mg/L and significantly slower (t > 1 week) for [Pb aq ] initial = 10 mg/L. Speciation calculations revealed that after a long time of interaction (1 month), all the solutions reached equilibrium with respect to both gypsum and anglesite. For [Pb aq ] initial ≥ 100 mg/L, sorption takes place mainly via the rapid dissolution of gypsum and the simultaneous formation of anglesite both on the gypsum surface and in the bulk solution. In the case of [Pb aq ] initial = 10 mg/L, no anglesite precipitation was observed, but surface spectroscopy (proton Rutherford Backscattering Spectroscopy, p-RBS) confirmed the formation of Pb-bearing surface layers on the (0 1 0) gypsum surface in this case also. This study shows that the surface of gypsum can play an important role in the attenuation of Pb in contaminated waters.
16. Characterization of a lime-pozzolan plaster containing phase change material
International Nuclear Information System (INIS)
Pavlíková, Milena; Pavlík, Zbyšek; Trník, Anton; Pokorný, Jaroslav; Černý, Robert
2015-01-01
A PCM (Phase Change Material) modified lime-pozzolan plaster for improvement of thermal energy storage of building envelopes is studied in the paper. The investigated plaster is composed of lime hydrate, pozzolan admixture based on metakaolin and mudstone, silica sand, water and paraffin wax encapsulated in polymer capsule. The reference plaster without PCM application is studied as well. The analyzed materials are characterized by bulk density, matrix density, total open porosity, compressive strength and pore size distribution. The temperature of phase change, heat of fusion and crystallization are studied using DSC (Difference Scanning Calorimetry) analysis performed in air atmosphere. In order to get information on materials hygrothermal performance, determination of thermal and hygric properties is done in laboratory conditions. Experimental data reveal a substantial improvement of heat storage capacity of PCM-modified plaster as compared to the reference material without PCM
17. Treatment of unicameral bone cysts by curettage and packing with plaster-of-Paris pellets. 1978.
Science.gov (United States)
Peltier, Leonard F; Jones, Richard H
2004-05-01
Long-term follow-up of twenty-six patients with unicameral bone cysts treated by curettage and packing with plaster-of-Paris pellets showed a recurrence in only two cases and no serious complications.
18. Sustainable Uses of FGD Gypsum in Agricultural Systems: Introduction.
Science.gov (United States)
Watts, Dexter B; Dick, Warren A
2014-01-01
Interest in using gypsum as a management tool to improve crop yields and soil and water quality has recently increased. Abundant supply and availability of flue gas desulfurization (FGD) gypsum, a by-product of scrubbing sulfur from combustion gases at coal-fired power plants, in major agricultural producing regions within the last two decades has attributed to this interest. Currently, published data on the long-term sustainability of FGD gypsum use in agricultural systems is limited. This has led to organization of the American Society of Agronomy's Community "By-product Gypsum Uses in Agriculture" and a special collection of nine technical research articles on various issues related to FGD gypsum uses in agricultural systems. A brief review of FGD gypsum, rationale for the special collection, overviews of articles, knowledge gaps, and future research directions are presented in this introductory paper. The nine articles are focused in three general areas: (i) mercury and other trace element impacts, (ii) water quality impacts, and (iii) agronomic responses and soil physical changes. While this is not an exhaustive review of the topic, results indicate that FGD gypsum use in sustainable agricultural production systems is promising. The environmental impacts of FGD gypsum are mostly positive, with only a few negative results observed, even when applied at rates representing cumulative 80-year applications. Thus, FGD gypsum, if properly managed, seems to represent an important potential input into agricultural systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.
19. The topical 5% lidocaine medicated plaster in localized neuropathic pain: a reappraisal of the clinical evidence
Directory of Open Access Journals (Sweden)
de León-Casasola OA
2016-02-01
Full Text Available Oscar A de León-Casasola,1,2 Victor Mayoral3 1Department of Anesthesiology, Division of Pain Medicine, Roswell Park Cancer Institute, 2University at Buffalo, School of Medicine and Biomedical Sciences. NY, USA; 3Anesthesiology Department, Pain Management Unit, University Hospital of Bellvitge, L'Hospitalet de Llobregat, Spain Abstract: Topical 5% lidocaine medicated plasters represent a well-established first-line option for the treatment of peripheral localized neuropathic pain (LNP. This review provides an updated overview of the clinical evidence (randomized, controlled, and open-label clinical studies, real-life daily clinical practice, and case series. The 5% lidocaine medicated plaster effectively provides pain relief in postherpetic neuralgia, and data from a large open-label controlled study indicate that the 5% lidocaine medicated plaster is as effective as systemic pregabalin in postherpetic neuralgia and painful diabetic polyneuropathy but with an improved tolerability profile. Additionally, improved analgesia and fewer side effects were experienced by patients treated synchronously with the 5% lidocaine medicated plaster, further demonstrating the value of multimodal analgesia in LNP. The 5% lidocaine medicated plaster provides continued benefit after long-term (≤7 years use and is also effective in various other LNP conditions. Minor application-site reactions are the most common adverse events associated with the 5% lidocaine medicated plaster; there is minimal risk of systemic adverse events and drug–drug interactions. Although further well-controlled studies are warranted, the 5% lidocaine medicated plaster is efficacious and safe in LNP and may have particular clinical benefit in elderly and/or medically compromised patients because of the low incidence of adverse events. Keywords: 5% lidocaine medicated plaster, clinical evidence, localized neuropathic pain, postherpetic neuralgia, review
20. Process for reducing radioactive contamination in waste product gypsum
International Nuclear Information System (INIS)
Lange, P.H. Jr.
1979-01-01
A process is described for reducing the radioactive contamination in waste product gypsum in which waste product gypsum is reacted with a dilute sulfuric acid containing barium sulfate to form an acid slurry at an elevated temperature, the slurry is preferably cooled, the acid component is separated from the solid, and the resulting solid is separated into a fine fraction and a coarse fraction. The fine fraction predominates in barium sulfate and radioactive contamination. The coarse fraction predominates in a purified gypsum product of reduced radioactive contamination
1. Design and properties of plaster mortars manufactured with ladle furnace slag
International Nuclear Information System (INIS)
Rodríguez, A.; Gutiérrez-González, S.; Horgnies, M.; Calderón, V.
2013-01-01
Highlights: • This study analyses plaster with ladle furnace slag as a mineral aggregate. • Tests are completed by characterizing the influences of two admixtures. • Microstructure, physical and mechanical results confirm the feasibility of these materials. • These new materials are potentially useful as plaster mortars for use in masonry. - Abstract: This study deals with the properties of a series of plasters containing different proportions of ladle furnace slag used as mineral aggregate. The tests characterise the influences of two admixtures: a superfluidifier to reduce the water absorption (SikaMix®) of mortar plaster and an adhesive emulsion to improve the surface adherence (SikaLatex®). The physical and mechanical results confirm the feasibility of employing ladle furnace slag as a mineral aggregate, which induces an increase in density, in vapour permeability and in porosity. The results highlight also a decrease of adherence, durability and mechanical strength, proportionally to the amount of plaster substituted by slag. Scanning electron microscopy imaging and elemental mapping show good interaction between the various constituents. The thermal degradation of the mixtures reflects an improvement in strength resistance in relation to temperature, as further slag is incorporated. The economical study suggests that these recycled materials are cost-effectively viable and may be applied as plaster mortars for use in masonry
2. Preparation of Plaster Moulage (Cast in Plastic Surgery patients
Directory of Open Access Journals (Sweden)
Rana R
2003-01-01
Full Text Available The purpose of this paper is to describe the technique of making casts using alginate compound for negative and dental stone plaster for positive impressions. With certain modifications a cast could be made of any part of the body and one can make a museum of interesting cases. Casts serve as useful teaching material especially in cleft lip and palate patients to study the effect of surgery on growth and development of the cleft lip-palate-nose complex in relation to the remaining face. It also helps in planning reconstruction in cases of facial defects, recording serial changes in multistage surgery, pre-operative and post-operative comparison as in rhinoplasty, ear reconstruction, hand etc; for comparing results before and after treatment in keloid and hypertrophic scars, fabrication of implants and preparation of prosthesis. In spite of newer modalities like 3-D imaging and stereolithography, the usefulness of this old technique in certain interesting cases can not be denied.
3. Tratamentos superficiais visando à melhoria da aderência entre gesso e taliscas de bambu Surface treatments aimed at improving the adhesion between plaster and bamboo slivers
Directory of Open Access Journals (Sweden)
Cibelle G Silva
2012-02-01
4. Assessment of Natural Exposure From Some kinds of Egyptian Gypsum Using Low Background Spectrometer
International Nuclear Information System (INIS)
Sroor, A.
2006-01-01
Radioactivity of natural gypsum and gypsum derived products are examined investigated due to their importance as element of building materials and agricultural gypsum. the natural gypsum and its product may constitute an additional source of radiation exposure to workers and members of public from radiation produced by radioactive decaying. thirty natural gypsum samples from different quarries and 32 fabricated gypsum samples from commercial companies were analyzed using low background HPGe detector. the natural concentration of Ra-226, 232 Th and 40 K activities in all samples were determined in Bq/Kg dry weight. it was found that radioactivity of natural gypsum is less than the fabricated gypsum, so it can be used as agricultural gypsum. fabricated gypsum is suitable for use as an element of building material in egypt
5. Radium uptake by recrystallized gypsum: an incorporation study
International Nuclear Information System (INIS)
Lestini, Leslie; Beaucaire, Catherine; Vercouter, Thomas; Descostes, Michael
2013-01-01
Batch experiments of 226 Ra uptake by recrystallized gypsum CaSO 4 .2H 2 O(s), monitored over 200 days, have shown that the published value for the distribution coefficient of 226 Ra between gypsum and an aqueous phase, 0.03 (Gnanapragasam and Lewis, 1995), is an upper limit. This suggests that this value needs to be confirmed. A solid solution between gypsum and radium sulfate (Ca,Ra)SO 4 .2H 2 O(s) cannot be considered per se, which is not surprising considering gypsum's high solubility product (lg Ks = -4.58) and the ionic radius of VIII Ra (1.48 A), when compared to that of VIII Ca (1.12 A). (authors)
6. Uranium-series dating of gypsum speleothems: methodology and examples.
Directory of Open Access Journals (Sweden)
Sanna Laura
2010-01-01
Full Text Available The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gypsum speleothems are, in general, very low in U content, challenging the limits of detection methods. Various approaches to dissolving gypsum and isolation of actinides from the matrix include ion-pairing dissolution with magnesium salts and using nitric acid. The most precise dating technique is Thermal Ionization Mass Spectrometry (TIMS, combined with Fe(OH3 scavenging and anionic exchange chromatography. Less satisfactory, but much quicker, is direct retention of actinides from HNO3 by means of TRU resin and MC-ICP-MS detection. We have tested these methods on gypsum speleothems from the Sorbas karst in Spain and from the Naica caves in Mexico.
7. Gypsum crystals in the inner shelf sediments off Maharashtra, India
Digital Repository Service at National Institute of Oceanography (India)
Hashimi, N.H.; Ambre, N.V.
Gypsum crystals have been found in the inner shelf silty clay/clayey silt off the Maharashtra Coast between Vengurla and Bombay. Generally these occur as euhedral single or twinned crystals of selenite. Very often shells are found embedded within...
8. Preliminary Estimate of Gypsum Deposit Based on Wenner
African Journals Online (AJOL)
Dogara M. D. and Aloa J. O.
estimating the quantity of some possible deposits of gypsum. Just ... exploitation is an everyday activity that is currently going on, but, on a 'wild cat' ... important source of wealth for a nation, but before they are harnessed ..... REFERENCES.
9. Direct and indirect dating of gypsum occurrences in deserts using luminescence methods
International Nuclear Information System (INIS)
Nagar, Y.C.; Juyal, N.; Singhyi, A.K.; Kocurek, G.; Wadhawan, S.K.
2005-01-01
In the present study we have made an attempt to directly date gypsum or provide indirect age estimate for gypsum formation through dating the associated sediments (quartz) using the luminescence dating technique. In the direct dating of gypsum, we explored the Optically Stimulated Luminescence (OSL) and Thermally Stimulated Luminescence (TL) behaviour of gypsum. The associated sediments (indirect dating) were dated using the traces of quartz extract from gypsum (concentration 0.1% ) and the underlying and overlying quartz sand in playa
10. Crystallisation of Gypsum and Prevention of Foaming in Wet Flue Gas Desulphurisation (FGD) Plants
DEFF Research Database (Denmark)
Hansen, Brian Brun
The aim of this project is to investigate two operational problems, which have been experienced during wet flue gas desulphurisation (FGD) operation, i.e. poor gypsum dewatering properties and foaming. The results of this work can be used for the optimization of wet FGD-plants in terms of reliabi......The aim of this project is to investigate two operational problems, which have been experienced during wet flue gas desulphurisation (FGD) operation, i.e. poor gypsum dewatering properties and foaming. The results of this work can be used for the optimization of wet FGD-plants in terms....... Experiments in a falling film wet FGD pilot plant have shown a strong non-linear behaviour (in a ln(n(l)) vs. l plot) at the lower end of the particle size range, compared to the well-known linear “mixed suspension mixed product removal (MSMPR)” model. A transient population balance model, fitted...
11. Characterization mixtures of thick gypsum with addition of treated waste from laminated plasterboards
Directory of Open Access Journals (Sweden)
Rodríguez-Orejón, A.
2014-06-01
12. Interaction of gypsum with lead in aqueous solutions
Energy Technology Data Exchange (ETDEWEB)
Astilleros, J.M., E-mail: [email protected] [Dpto. Cristalografia y Mineralogia, Universidad Complutense de Madrid, Jose Antonio Novais, 2, E-28040 Madrid (Spain); Godelitsas, A. [Department of Mineralogy and Petrology, Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupoli Zographou, 15784 Athens (Greece); Rodriguez-Blanco, J.D. [School of Earth and Environments, Faculty of Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Fernandez-Diaz, L. [Dpto. Cristalografia y Mineralogia, Universidad Complutense de Madrid, Jose Antonio Novais, 2, E-28040 Madrid (Spain); Prieto, M. [Dpto. de Geologia, Universidad de Oviedo, E-30005 Oviedo (Spain); Lagoyannis, A.; Harissopulos, S. [Tandem Accelerator Laboratory, Institute of Nuclear Physics, NCSR ' Demokritos' , GR-15310 Attiki (Greece)
2010-07-15
Sorption processes on mineral surfaces are a critical factor in controlling the distribution and accumulation of potentially harmful metals in the environment. This work investigates the effectiveness of gypsum (CaSO{sub 4}.2H{sub 2}O) to sequester Pb. The interaction of gypsum fragments with Pb-bearing solutions (10, 100 and 1000 mg/L) was monitored by performing macroscopic batch-type experiments conducted at room temperature. The aqueous phase composition was periodically determined by Atomic Absorption Spectrometry (AAS), Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Regardless of the [Pb{sub aq}]{sub initial}, a [Pb{sub aq}]{sub final} < 4 mg/L was always reached. The uptake process was fast (t < 1 h) for [Pb{sub aq}]{sub initial} {>=} 100 mg/L and significantly slower (t > 1 week) for [Pb{sub aq}]{sub initial} = 10 mg/L. Speciation calculations revealed that after a long time of interaction (1 month), all the solutions reached equilibrium with respect to both gypsum and anglesite. For [Pb{sub aq}]{sub initial} {>=} 100 mg/L, sorption takes place mainly via the rapid dissolution of gypsum and the simultaneous formation of anglesite both on the gypsum surface and in the bulk solution. In the case of [Pb{sub aq}]{sub initial} = 10 mg/L, no anglesite precipitation was observed, but surface spectroscopy (proton Rutherford Backscattering Spectroscopy, p-RBS) confirmed the formation of Pb-bearing surface layers on the (0 1 0) gypsum surface in this case also. This study shows that the surface of gypsum can play an important role in the attenuation of Pb in contaminated waters.
13. A comparison of the accuracy of polyether, polyvinyl siloxane, and plaster impressions for long-span implant-supported prostheses.
Science.gov (United States)
Hoods-Moonsammy, Vyonne J; Owen, Peter; Howes, Dale G
2014-01-01
The purpose of this study was to compare the capacity of different impression materials to accurately reproduce the positions of five implant analogs on a master model by comparing the resulting cast with the stainless steel master model. The study was motivated by the knowledge that distortions can occur during impression making and the pouring of casts and that this distortion may produce inaccuracies of subsequent restorations, especially long-span castings for implant superstructures. The master model was a stainless steel model with five implant analogs. The impression materials used were impression plaster (Plastogum, Harry J Bosworth), a polyether (Impregum Penta, 3M ESPE), and two polyvinyl siloxane (PVS) materials (Aquasil Monophase and Aquasil putty with light-body wash, Dentsply). Five impressions were made with each impression material and cast in die stone under strictly controlled laboratory conditions. The positions of the implants on the master model, the impression copings, and the implant analogs in the subsequent casts were measured using a coordinate measuring machine that measures within 4 μm of accuracy. Statistical analyses indicated that distortion occurred in all of the impression materials, but inconsistently. The PVS monophase material reproduced the master model most accurately. Although there was no significant distortion between the impressions and the master model or between the impressions and their casts, there were distortions between the master model and the master casts, which highlighted the cumulative effects of the distortions. The polyether material proved to be the most reliable in terms of predictability. The impression plaster displayed cumulative distortion, and the PVS putty with light body showed the least reliability. Some of the distortions observed are of clinical significance and likely to contribute to a lack of passive fit of any superstructure. The inaccuracy of these analog materials and procedures suggested
14. Light Steel-Timber Frame with Composite and Plaster Bracing Panels
Directory of Open Access Journals (Sweden)
Roberto Scotta
2015-11-01
Full Text Available The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerical model was calibrated on experimental results and the dynamic non-linear behavior of a case-study building was assessed. Numerical results were then used to estimate the proper behavior factor value, according to European seismic codes. Obtained results demonstrate that this innovative system is suitable for the use in seismic-prone areas thanks to the high ductility and dissipative capacity achieved by the bracing system. This favorable behavior is mainly due to the fasteners and materials used and to the correct application of the capacity design approach.
15. Light Steel-Timber Frame with Composite and Plaster Bracing Panels.
Science.gov (United States)
Scotta, Roberto; Trutalli, Davide; Fiorin, Laura; Pozza, Luca; Marchi, Luca; De Stefani, Lorenzo
2015-11-03
The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB) sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerical model was calibrated on experimental results and the dynamic non-linear behavior of a case-study building was assessed. Numerical results were then used to estimate the proper behavior factor value, according to European seismic codes. Obtained results demonstrate that this innovative system is suitable for the use in seismic-prone areas thanks to the high ductility and dissipative capacity achieved by the bracing system. This favorable behavior is mainly due to the fasteners and materials used and to the correct application of the capacity design approach.
16. CLINICAL OBSERVATION ON TREATMENT OF 61 CASES OF INSOMNIA WITH AURICULAR PLASTER THERAPY
Institute of Scientific and Technical Information of China (English)
张家彤; 王月
2003-01-01
Objective: To observe the therapeutic effect of auricular plaster (otopoint-pressure) therapy in thetreatment of insomnia. Methods: In this paper, 61 cases of insomnia patients including 16 males and 45 females weretreated with Ershenmen (MA-TF 1), Zhen (MA-AT), Yuanzhong (MA-AT), Nao Dian and E (MA-AT), combined withother otopoints according to symptoms. The otopoint was stuck with a piece of plaster adhered with vaccaria seeds andpressured by the patient him- or her-self. The treatment was given twice a week, with 7 times being a therapeuticcourse. Results: After 1 - 2 courses of treatment, 19 (31.15%) cases were cured, 34 (55.74 % ) had improvementand 8 (13.11%) had no changes, with the total effective rate being 86.9%. Conclusion: Auricular plaster therapyworks well in the treatment of insomnia patient.
17. Hydration modeling of calcium sulphates
NARCIS (Netherlands)
de Korte, A.C.J.; Brouwers, H.J.H.; Al-Mattarneh, Hashem; Mustapha, Kamal N.; Nuruddin, Muhd Fadhil
2008-01-01
The CEMHYD3D model has been extended at the University of Twente in the last ten years [1,2]. At present the cement hydration model is extended for the use of gypsum. Although gypsum was present in the model already, the model was not suitable for high contents of gypsum and did not include the
18. Synthesis on research results of FGD gypsum briquetting
Directory of Open Access Journals (Sweden)
Kosturkiewicz Bogdan
2017-01-01
Full Text Available FGD gypsum products can be characterized by significant solubility in water and dusting in dry state. These characteristics can cause a considerable pollution of air, water and soil. Among many approaches of preparing utilization of this waste, the process of compaction using briquetting has proved to be very effective. Using FGD gypsum products a new material of fertilizers characteristics has been acquired and this material is resistant to the conditions of transportation. This paper presents results of experimental briquetting of flue gas desulphurisation products in a roll press. The experiments were conducted in a laboratory roll presses LPW 450 and LPW 1100 equipped with two interchangeable forming rings that form material into saddle-shaped briquettes with volume 6,5 cm3 and 85 cm3. The experiments were conducted with various percentage amounts of FGD gypsum moisture. The results provided information regarding influence of moisture and roll press configuration on quality of briquettes. On the basis of obtained results, technological process and a general outline of technological line for FGD gypsum were developed. Two roll presses of own construction with different outputs were identified as appropriate for this purpose. A range of necessary works related to their adaptation for the FGD gypsum briquetting were pointed out.
19. Converting SDAP into gypsum in a wet limestone scrubber
Energy Technology Data Exchange (ETDEWEB)
Fogh, F [Faelleskemikerne, Elsamprojekt A/S, Fredericia (Denmark)
1996-12-01
The ELSAM power pool has an installed electrical capacity of approx. 5 GW{sub e}, mainly firing import coal. The major base load units are equipped with desulphurization units and three different desulphurization technologies are used: the wet limestone gypsum process, the spray dry absorption process and a sulphuric acid process. Gypsum and sulphuric acid are commercialized, whereas it has been difficult to utilize the spray dry absorption product (SDAP). The main constituents of SDAP are calcium sulphide, calcium chloride, hydrated lime and impurities mainly originating from fly ash. Sulphide can be oxidized into sulphate in acidic solution - the reaction is utilized in the wet limestone gypsum process - and the possibility of using any spare capacity in the wet limestone gypsum units to oxidize the sulphide content of SDAP into sulphate and produce usable gypsum has been investigated in the laboratory and in a 400 MW{sub e} equivalent wet limestone unit. The limestone inhibition effect of the addition of SDAP is currently being studied in the laboratory in order to determine the effect of different SDAP types (plant/coal sources) on limestone reactivity before further long-term full-scale tests are performed and permanent use of the process planned. (EG)
20. Towards establishing a combined rate law of nucleation and crystal growth - The case study of gypsum precipitation
Science.gov (United States)
Rendel, Pedro M.; Gavrieli, Ittai; Wolff-Boenisch, Domenik; Ganor, Jiwchar
2018-03-01
The main obstacle in the formulation of a quantitative rate-model for mineral precipitation is the absence of a rigorous method for coupling nucleation and growth processes. In order to link both processes, we conducted a series of batch experiments in which gypsum nucleation was followed by crystal growth. Experiments were carried out using various stirring methods in several batch vessels made of different materials. In the experiments, the initial degree of supersaturation of the solution with respect to gypsum (Ωgyp) was set between 1.58 and 1.82. Under these conditions, heterogeneous nucleation is the dominant nucleation mode. Based on changes in SO42- concentration with time, the induction time of gypsum nucleation and the following rate of crystal growth were calculated for each experiment. The induction time (6-104 h) was found to be a function of the vessel material, while the rates of crystal growth, which varied over three orders of magnitude, were strongly affected by the stirring speed and its mode (i.e. rocking, shaking, magnetic stirrer, and magnetic impeller). The SO42- concentration data were then used to formulate a forward model that couples the simple rate laws for nucleation and crystal growth of gypsum into a single kinetic model. Accordingly, the obtained rate law is based on classical nucleation theory and heterogeneous crystal growth.
1. Effect of Time on Gypsum-Impression Material Compatibility
Science.gov (United States)
Won, John Boram
The purpose of this study was to evaluate the compatibility of dental gypsum with three recently introduced irreversible hydrocolloid (alginate) alternatives. The test materials were Alginot® (Kerr™), Position Penta Quick® (3M ESPE™) and Silgimix ® (Sultan Dental™). The irreversible hydrocolloid impression material, Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control. Materials and Methods: Testing of materials was conducted in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials. Statistical Analysis: The 3-Way ANOVA test was used to analyze measurements between different time points at a significance level of (p Outcome: It was found that there was greater compatibility between gypsum and the alternative materials over time than the traditional irreversible hydrocolloid material that was tested. A statistically significant amount of surface change/incompatibility was found over time with the combination of the dental gypsum products and the control impression material (Jeltrate Plus antimicrobial®).
2. Triple oxygen isotope systematics of structurally bonded water in gypsum
Science.gov (United States)
Herwartz, Daniel; Surma, Jakub; Voigt, Claudia; Assonov, Sergey; Staubwasser, Michael
2017-07-01
The triple oxygen isotopic composition of gypsum mother water (gmw) is recorded in structurally bonded water in gypsum (gsbw). Respective fractionation factors have been determined experimentally for 18O/16O and 17O/16O. By taking previous experiments into account we suggest using 18αgsbw-gmw = 1.0037; 17αgsbw-gmw = 1.00195 and θgsbw-gmw = 0.5285 as fractionation factors in triple oxygen isotope space. Recent gypsum was sampled from a series of 10 ponds located in the Salar de Llamara in the Atacama Desert, Chile. Total dissolved solids (TDS) in these ponds show a gradual increase from 23 g/l to 182 g/l that is accompanied by an increase in pond water 18O/16O. Gsbw falls on a parallel curve to the ambient water from the saline ponds. The offset is mainly due to the equilibrium fractionation between gsbw and gmw. However, gsbw represents a time integrated signal biased towards times of strong evaporation, hence the estimated gmw comprises elevated 18O/16O compositions when compared to pond water samples taken on site. Gypsum precipitation is associated with algae mats in the ponds with lower salinity. No evidence for respective vital effects on the triple oxygen isotopic composition of gypsum hydration water is observed, nor are such effects expected. In principle, the array of δ18Ogsbw vs. 17Oexcess can be used to: (1) provide information on the degree of evaporation during gypsum formation; (2) estimate pristine meteoric water compositions; and (3) estimate local relative humidity which is the controlling parameter of the slope of the array for simple hydrological situations. In our case study, local mining activities may have decreased deep groundwater recharge, causing a recent change of the local hydrology.
3. Chemical properties of an Oxisol after gypsum application
Directory of Open Access Journals (Sweden)
Victor Roncaratti de Moraes
2016-10-01
Full Text Available Gypsum utilization is a critical practice in agriculture because of the high solubility and consequent relative neutralization of subsurface toxic aluminum. However, it has been observed that in most cases, gypsum is being randomly utilized without scientifically established parameters or even the need to use it as a soil amendment at all. The objective of this study was to evaluate the chemical composition and electrical conductivity of an Oxisol’s saturation extract under different gypsum doses (0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1. This experiment was conducted in a greenhouse environment. Soil columns (V = 1.57 dm3 were filled with sifted (2 mm soil collected from the upper layer (0-20 cm. The experimental design adopted was completely randomized with five repetitions. The treatments consisted of a 5 × 2 factorial through five gypsum doses (0.0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1 of gypsum consisting of 224.1 g kg-1 S, 314.8 g kg-1 CaO, and 7 g kg-1 P2O5 and two depth evaluations (0-10 and 10-20 cm. After the treatments, soil from both 0-10 cm and 10-20 cm layers was removed from the columns, sifted once (2 mm, and subjected to vacuum extraction to assess the saturation extract. The data acquired was processed and submitted to variance analysis (when due and adjusted to regression equations when statistically relevant. Significant increases were observed for Ca, Mg, K, P, and S, although Al, Si, and pH presented no statistically significant difference. The electrical conductivity value of this soil in particular is directly related to the gypsum dose.
4. Characterization of quality recycled gypsum and plasterboard with maximized recycled content
International Nuclear Information System (INIS)
Jiménez-Rivero, J.; García-Navarro, J.
2017-01-01
The quality of secondary materials is imperative to promote a circular economy. In order to improve the way in which the quality of recycled gypsum is assessed, European guidelines on recycled gypsum (RG) quality criteria have been outlined in the framework of the Life+ Gypsum to Gypsum (GtoG) project. Such GtoG guidelines, along with the European Standard on gypsum plasterboard EN 520, provided the basis for this study. During the GtoG project, gypsum recycling and plasterboard manufacturing processes were monitored by testing the gypsum feedstock and the plasterboard produced. The aim of this paper is to discuss the results obtained on relevant parameters that characterize gypsum as a secondary raw material, as well as the resulting product. The minimum requirements were fulfilled by 56% of the RG samples and 86% of the plasterboard with increased RG. [es
5. Restorian of outdoor plaster pavement floors in a medieval Czech castle
Czech Academy of Sciences Publication Activity Database
Slížková, Zuzana; Drdácký, Miloš
2008-01-01
Roč. 14, č. 3 (2008), s. 81-98 ISSN 1355-6207 R&D Projects: GA ČR(CZ) GA103/06/1609 Institutional research plan: CEZ:AV0Z20710524 Keywords : floor plaster * metakaoline modified mortar * medieval castle rampart * non-standard testing Subject RIV: AL - Art, Architecture, Cultural Heritage
6. Fragmentation, Cost and Environmental Effects of Plaster Stemming Method for Blasting at A Basalt Quarry
Science.gov (United States)
Cevizci, Halim
2014-10-01
In this study, the plaster stemming application for blasting at a basalt quarry is studied. Drill cuttings are generally used in open pits and quarries as the most common stemming material since these are most readily available at blast sites. However, dry drill cuttings eject very easily from blastholes without offering much resistance to blast energy. The plaster stemming method has been found to be better than the drill cuttings stemming method due to increased confinement inside the hole and better utilization of blast explosive energy in the rock. The main advantage of the new stemming method is the reduction in the cost of blasting. At a basalt quarry, blasting costs per unit volume of rock were reduced to 15% by increasing burden and spacing distances. In addition, better fragmentation was obtained by using the plaster stemming method. Blast trials showed that plaster stemming produced finer material. In the same blast tests, +30 cm size fragments were reduced to 47.3% of the total, compared to 32.6% in the conventional method of drill cuttings stemming. With this method of stemming, vibration and air shock values increased slightly due to more blast energy being available for rock breakage but generally these increased values were small and stayed under the permitted limit for blast damage criteria unless measuring distance is too close.
7. Mineralogical and textural characterization of mortars and plasters from the archaeological site of Barsinia, northern Jordan
Directory of Open Access Journals (Sweden)
2014-12-01
Full Text Available Twelve mortar and plaster samples excavated in the archaeological site of Barsinia were mineralogically and petrographically examined by XRay Diffraction (XRD and Stereo and Polarized Light Microscopy, while the total carbonate content was measured using a DietrichFruhling Calcimeter. The physical properties of the samples, such as water uptake under atmospheric pressure and under vacuum, together with density and porosity, were measured. Only twelve samples were available for the purposes of this study: 8 plaster samples and 4 mortar samples. Eleven samples out of the total number of samples were mortars or plasters with lime binder and silica aggregate; calcite and quartz were identified in all of these samples. In most of the samples one or more pozzolanic components were detected; a hydraulic effect therefore exists in practically most of the studied mortars. Excluding the plasters taken from waterbearing constructions such as cisterns, and the mortar sample from the compact floor, the binder content is high; in general, the overall porosity of the studied samples is high. Porosity and petrographic investigation results suggest that the burning temperature of the limestone was low and/or the duration of the combustion was short; such preparation conditions produce a desirable quicklime. Owing to the significant compositional and textural differences between the samples that were reported, there is consequently no suitable general mortar that can be adopted for the restoration of the whole site.
8. No bulging of floor heating pipes to be expected in case of incomplete floor plastering
Energy Technology Data Exchange (ETDEWEB)
1983-02-01
According to advertising slogans floor heating pipes are said to be damaged prematurely by bulges if they are not completely surrounded by flooring plaster. The author has thoroughly dealt with this problem and made the respective measurements. He found out that there are so few bulges occurring that they cannot lead to damages.
9. Forty Cases of Insomnia Treated by Multi-output Electric Pulsation and Auricular Plaster Therapy
Institute of Scientific and Technical Information of China (English)
Liu Weizhe
2007-01-01
@@ The writer has treated 40 cases of insomnia by the method of multi-output electric pulsation in combination with auricular plaster therapy (with a seed of Vaccariae segetalis 王不留行 taped tightly to a particular ear point and pressed) and received satisfactory therapeutic effects. A report follows.
10. Reproducibility of the index of orthognathic functional treatment need scores derived from plaster study casts and their three-dimensional digital equivalents: a pilot study.
Science.gov (United States)
McCrory, Emma; McGuinness, Niall Jp; Ulhaq, Aman
2018-06-01
To determine the reproducibility of Index of Orthognathic Functional Treatment Need (IOFTN) scores derived from plaster casts and their three-dimensional (3D) digital equivalents. Pilot study, prospective analytical. UK hospital orthodontic department. Thirty casts and their digital equivalents, representing the pre-treatment malocclusions of patients requiring orthodontic-orthognathic surgical treatment, were scored by four clinicians using IOFTN. Casts were scanned using a 3Shape digital scanner and 3D models produced using OrthoAnalyzer TM (3Shape Ltd, Copenhagen, Denmark). Examiners independently determined the IOFTN scores for the casts and digital models, to test their inter- and intra-operator reliability using weighted Kappa scores. Intra-operator agreement with IOFTN major categories (1-5: treatment need) was very good for plaster casts (0.83-0.98) and good-very good for digital models (0.78-0.83). Inter-operator agreement was moderate-very good for casts (0.58-0.82) and good-very good for digital models (0.65-0.92). Intra-operator agreement with IOFTN sub-categories (1-14: feature of malocclusion) was good-very good for casts (0.70-0.97) and digital models (0.80-0.94). Inter-operator agreement was moderate-good for casts (0.53-0.77); and moderate-very good for the digital models (0.58-0.90). Digital models are an acceptable alternative to plaster casts for examining the malocclusion of patients requiring combined orthodontic-orthognathic surgical treatment and determining treatment need.
11. Development of gypsum alteration on marble and limestone
Science.gov (United States)
McGee, E.S.
1996-01-01
Blackened alteration crusts of gypsum plus particulates that form on sheltered areas on marble and limestone buildings pose a challenge for rehabilitation and cleaning. Fresh marble and limestone samples exposed at monitored exposure sites present conditions of simple geometry and well-documented exposures but have short exposure histories (one to five years). The gypsum alteration crusts that develop on these samples provide insight into the early stages and rate of alteration crust formation. Alteration crusts from buildings give a longer, but less well known exposure history and present much more complex surfaces for gypsum accumulation. Integrated observations and measurements of alteration crusts from exposure samples and from buildings identify four factors that are important in the formation and development of alteration crusts on marble and limestone: (1) pollution levels, (2) exposure to rain or washing, (3) geometry of exposure of the stone surface, and (4) permeability of the stone. The combination of these factors contributes to both the distribution and the physical characteristics of the gypsum crusts which may affect cleaning decisions.
12. Composite Gypsum Binders with Silica-containing Additives
Science.gov (United States)
Chernysheva, N. V.; Lesovik, V. S.; Drebezgova, M. Yu; Shatalova, S. V.; Alaskhanov, A. H.
2018-03-01
New types of fine mineral additives are proposed for designing water-resistant Composite Gypsum Binders (CGB); these additives significantly differ from traditional quartz feed: wastes from wet magnetic separation of Banded Iron Formation (BIF WMS waste), nanodispersed silica powder (NSP), chalk. Possibility of their combined use has been studied as well.
13. Preparation of gypsum/polymer composites using radiation
International Nuclear Information System (INIS)
Aji, Z.
2007-05-01
Gypsum composites have been prepared with different monomers using Gamma radiation: acrylamide, butyl acrylate, butyl methacrylate, methyl methacrylate, and methyl acrylate. The conversion of polymerization was determined as a function of absorbed dose. The data show that conversion of polymerization increases by increasing the dose.(author)
14. Influence of gypsum on efflorescence in ceramic tiles
International Nuclear Information System (INIS)
Monteiro, C.M.O.L.; Nascimento, R.M.; Martinelli, A.E.
2009-01-01
The red ceramic industry is recognized as of major importance in Piaui State. The State capital, Teresina, is the greatest producer of this material, which is used mainly for masonry sealing blocks. One of the most frequent problems in this kind of products is the efflorescence.This paper has the main objective of studying the influence of gypsum on tiles, using the local industry production standards. The raw materials were characterized by FRX, DRX, thermal analysis and sulfates. Extruded test specimens were made with the addition of 1%, 3% and 5% of gypsum in the ceramic paste, burned at 850 deg C, 950 deg C and 1050 deg C and submitted to further technological and analysis for MEV. The reference ceramic paste did not show tendency to efflorescence formation after burning for samples with 1% gypsum added to the paste. The reference ceramic paste showed tendency to efflorescence formation after drying and consolidated efflorescence after burning for samples with 5% gypsum added to the paste. (author)
15. Evaluation of gypsum rates on greenhouse crop production
Science.gov (United States)
This study was to determine the potential of an added value distribution channel for gypsum waste by evaluating various greenhouse crops with captious pH and calcium needs. Three studies consisting of: Zonal geranium (Pelargonium x hortorum) and petunia (Petunia x hybrida); tomato (Solanum lycoper...
16. Validation of plaster endocast morphology through 3D CT image analysis.
Science.gov (United States)
Schoenemann, P Thomas; Gee, James; Avants, Brian; Holloway, Ralph L; Monge, Janet; Lewis, Jason
2007-02-01
A crucial component of research on brain evolution has been the comparison of fossil endocranial surfaces with modern human and primate endocrania. The latter have generally been obtained by creating endocasts out of rubber latex shells filled with plaster. The extent to which the method of production introduces errors in endocast replicas is unknown. We demonstrate a powerful method of comparing complex shapes in 3-dimensions (3D) that is broadly applicable to a wide range of paleoanthropological questions. Pairs of virtual endocasts (VEs) created from high-resolution CT scans of corresponding latex/plaster endocasts and their associated crania were rigidly registered (aligned) in 3D space for two Homo sapiens and two Pan troglodytes specimens. Distances between each cranial VE and its corresponding latex/plaster VE were then mapped on a voxel-by-voxel basis. The results show that between 79.7% and 91.0% of the voxels in the four latex/plaster VEs are within 2 mm of their corresponding cranial VEs surfaces. The average error is relatively small, and variation in the pattern of error across the surfaces appears to be generally random overall. However, inferior areas around the cranial base and the temporal poles were somewhat overestimated in both human and chimpanzee specimens, and the area overlaying Broca's area in humans was somewhat underestimated. This study gives an idea of the size of possible error inherent in latex/plaster endocasts, indicating the level of confidence we can have with studies relying on comparisons between them and, e.g., hominid fossil endocasts. Copyright 2006 Wiley-Liss, Inc.
17. Multidisciplinary approach to improve the quality of below-knee plaster casting.
Science.gov (United States)
Williams, John Teudar; Kedrzycki, Marta; Shenava, Yathish
2018-01-01
In our trauma unit, we noted a high rate of incorrectly applied below-knee casts for ankle fractures, in some cases requiring reapplication. This caused significant discomfort and inconvenience for patients and additional burden on plaster-room services. Our aim was to improve the quality of plaster casts and reduce the proportion that needed to be reapplied. Our criteria for plaster cast quality were based on the British Orthopaedic Association Casting Standards (2015) and included neutral (plantargrade) ankle position, adequacy of fracture reduction and rate of cast reapplication. Baseline data collection was performed over a 2-month period by two independent reviewers. After distributing findings and presenting to relevant departments, practical casting sessions with orthopaedic technicians were arranged for the multidisciplinary team responsible for casting. This was later supplemented by new casting guidelines in clinical areas and available online. Postintervention data collection was performed over two separate cycles to assess the effect and permanence of intervention. Data from the preintervention period (n=29) showed median ankle position was 32° plantarflexion (PF), with nine (31%) inadequate reductions and six (20%) backslabs reapplied. Following Plan-Do-Study-Act (PDSA) 1, ankle position was significantly improved (median 25° PF), there were fewer inadequate reductions (12%; 2/17) and a lower rate of reapplication (0%; 0/17). After PDSA 2 (n=16), median ankle position was 21° PF, there was one (6%) inadequate reduction and two (12%) reapplications of casts. Following implementation of plaster training sessions for accident and emergency and junior orthopaedic staff, in addition to publishing guidance and new protocol, there has been a sustained improvement in the quality of below-knee backslabs and fewer cast reapplications. These findings justify continuation and expansion of the current programme to include other commonly applied plaster casts.
18. Theoretical and Numerical Investigation of the Cavity Evolution in Gypsum Rock
Science.gov (United States)
Li, Wei; Einstein, Herbert H.
2017-11-01
When water flows through a preexisting cylindrical tube in gypsum rock, the nonuniform dissolution alters the tube into an enlarged tapered tube. A 2-D analytical model is developed to study the transport-controlled dissolution in an enlarged tapered tube, with explicit consideration of the tapered geometry and induced radial flow. The analytical model shows that the Graetz solution can be extended to model dissolution in the tapered tube. An alternative form of the governing equations is proposed to take advantage of the invariant quantities in the Graetz solution to facilitate modeling cavity evolution in gypsum rock. A 2-D finite volume model was developed to validate the extended Graetz solution. The time evolution of the transport-controlled and the reaction-controlled dissolution models for a single tube with time-invariant flow rate are compared. This comparison shows that for time-invariant flow rate, the reaction-controlled dissolution model produces a positive feedback between the tube enlargement and dissolution, while the transport-controlled dissolution does not.
19. Physicochemical Properties and Cellular Responses of Strontium-Doped Gypsum Biomaterials
OpenAIRE
2012-01-01
This paper describes some physical, structural, and biological properties of gypsum bioceramics doped with various amounts of strontium ions (0.19–2.23 wt%) and compares these properties with those of a pure gypsum as control. Strontium-doped gypsum (gypsum:Sr) was obtained by mixing calcium sulfate hemihydrate powder and solutions of strontium nitrate followed by washing the specimens with distilled water to remove residual salts. Gypsum was the only phase found in the composition of both pu...
20. The Gypsum: White gold of Rajasthan, introduction, uses and future prospective
Science.gov (United States)
Sharma, Gayatri
2013-06-01
Rajasthan is mineral based state and Bikaner and its surrounding district have been gifted with Gypsum. Mt of Gypsum is available in these districts. Gypsum has multiple uses including basic raw material for POP industry, addition in cement and a natural fertilizer. This mineral has changes the economic scenario in the remote areas of Bikaner, Nagaur, Hanumangarh, Sanchore, Shriganganagar etc. Gypsum and selenite are mined about 3.0 million tons per year. There is huge demand from cement industry as Gypsum is added for improving setting time of cement. Gypsum is a natural fertilizer for alkaline land and it role is vital in state like India where alkaline land is major role. Its high use as fertilizer has potential to change millions of poor farmer families and improving in crop production. Cement Industry has started importing Gypsum from Thailand, Bankong, Pakistan, Iran etc. The mining of gypsum of purity of 70% CaSO4.2H2O is cooperative effort between the land owners and Rajasthan State Mines and Minerals Limited. Gypsum fulfills the demand of POP and Cement industry in Rajasthan and powder gypsum used in agriculture for recon dining of alkaline soil. This paper deals with multiple uses, availability, and future prospective of Gypsum, a white gold of Rajasthan.
1. Archaeomagnetic studies in central Mexico—dating of Mesoamerican lime-plasters
Science.gov (United States)
Hueda-Tanabe, Y.; Soler-Arechalde, A. M.; Urrutia-Fucugauchi, J.; Barba, L.; Manzanilla, L.; Rebolledo-Vieyra, M.; Goguitchaichvili, A.
2004-11-01
For the first time results of an archaeomagnetic study of unburned lime-plasters from Teotihuacan and Tenochtitlan in central Mesoamerica are presented. Plasters made of lime, lithic clasts and water, appear during the Formative Period and were used for a variety of purposes in floors, sculptures, ceramics and supporting media for mural paintings in the Oaxaca and Maya area. In Central Mexico, grinded volcanic scoria rich in iron minerals is incorporated into the lime-plasters mixture. Samples were selected from two archaeological excavation projects in the Teopancazco residential compound of Teotihuacan and the large multi-stage structure of Templo Mayor in Tenochtitlan, where chronological information is available. The intensity of remanent magnetization (natural remanent magnetization (NRM)) and low-field susceptibility are weak reflecting low relative content of magnetic minerals. NRM directions are well grouped and alternating field demagnetization shows single or two-component magnetizations. Rockmagnetic experiments point to fine-grained titanomagnetites with pseudo-single domain behavior. Anisotropy of magnetic susceptibility (AMS) measurements document a depositional fabric, with normal to free-surface minimum AMS axes. Characteristic mean site directions were correlated to the paleosecular variation curve for Mesoamerica. Data from Templo Mayor reflect recent tilting of the structures. Teopancazco mean site declinations show good correspondence with the reference curve, in agreement with the radiocarbon dating. Dates for four stages of Teotihuacan occupancy based on the study of lime-plasters range from AD 350 to 550. A date for a possible Mazapa occupation around AD 850 or 950 is also suggested based on the archaeomagnetic correlation. The archaeomagnetic record of a plaster floor in Teopancazco differed from the other nearby sites pointing to a thermoremanent magnetization; comparison with the reference curve suggests dates around AD 1375 or 1415. The
2. Predicting the durability of mineral external plaster using accelerated ageing tests; Prognose der Dauerhaftigkeit mineralischer Aussenputze mit Hilfe von beschleunigten Alterungstests
Energy Technology Data Exchange (ETDEWEB)
Bochen, Jerzy; Nowak, Henryk A. [Schlesische Technische Universitaet, Lehrstuhl Bauprozesse, Gliwice (Poland)
2004-08-01
This article presents a technique for accelerated ageing tests for different plasters. Two models were developed for describing the durability. The models describe changes in selected characteristics due to frost damage and leaching. The first model is based on changes in mass, the second on changes in strength. The models consider the main characteristics that influence durability, such as strength, porosity, permeability, adhesive tensil strength and aggressive environmental influences. Both models enable the durability of external plaster to be predicted. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Der Beitrag stellt eine Methode fuer beschleunigte Alterungstests von verschiedenen Putzen vor. Fuer die Beschreibung der Dauerhaftigkeit wurden zwei Modelle entwickelt. Die Modelle beschreiben Veraenderungen ausgewaehlter Eigenschaften, die infolge von Frostschaeden und Auslaugung auftreten. Das erste Modell basiert auf der Veraenderung der Masse und das zweite auf der Veraenderung der Festigkeit. In den Modellen werden die wesentlichen Eigenschaften beruecksichtigt, die die Dauerhaftigkeit beeinflussen, wie z. B. Festigkeit, Porositaet, Dichtigkeit, Haftzugfestigkeit und agressive Umwelteinwirkungen. Beide Modelle ermoeglichen die Prognose der Dauerhaftigkeit von Aussenputzen. (Abstract Copyright [2004], Wiley Periodicals, Inc.)
3. Moisture buffer capacity of cement-lime plasters with enhanced thermal storage capacity
Science.gov (United States)
Fořt, Jan; Pavlíková, Milena; Pavlík, Zbyšek
2017-07-01
Indoor air temperature and relative humidity represent important parameters for health and working efficiency of buildings occupants. Beside the moderation of temperature, investigation of hygric properties of building materials with connection to indoor relative humidity variation became recognized as a relevant factor for energy efficient building maintenance. The moisture buffer value introduced in the Nordtest protocol can be used for estimation of moisture buffer capacity of building materials or their multi-layered systems. In this paper, both the ideal and real moisture buffer values are examined on the basis of simulation of diurnal relative humidity fluctuations in plasters with incorporated PCM admixture. Retrieved data points to a complex effect of the tested plasters on possible moderation of buildings interior climate.
4. Possible Use of Diatomite and Pumice-Amended Mortar and Plaster in Agricultural Structures
Directory of Open Access Journals (Sweden)
Serkan Yazarel
2017-12-01
Full Text Available This study was conducted to investigate the potential use of diatomite (a natural pozzolana and pumice in plasters and mortars to be used in agricultural buildings. Compacted and loose unit weights, specific weight, water absorption, organic matter content, abrasion resistance of aggregate (sand and pumice and pozzolana were investigated and materials were found to comply with the relevant standards. Test results on fresh (unit weight and slum test and hardened (unit weight, capillary water absorption, total water absorption, bending and compressive strength, vapor diffusion test mortar samples revealed that pumice and diatomite could be used in agricultural structures. Diatomite and pumice should be heat-treated and grounded before to use in mortars. In plasters to be made with abundant pumice and diatomite sources, high water holding capacity of the materials should be taken into consideration and further researches should be carried out about their compliance with the other materials.
5. Basic Properties of Flue-Gas Desulfurization Gypsum
Directory of Open Access Journals (Sweden)
Kovacs Ferenc
2003-03-01
Full Text Available Several hundred thousand of FGD gypsum is produced annually at the Matra Power Plant (Hungary as a byproduct of generating electricity and protecting the environment. Chemical and mechanical characteristics of this material were studied of the Department of Mining and Geotechnical Engineering, University of Miskolc (Hungary. The material in question was found dead gypsum which can be calcined easily to obtain a relatively high-strength (15-25 MPa and clean binding material. Furthermore, grain composites were made of it by adding fly ash, which the power plant can provide the expected producers with, thus decreasing the energy consumption of calcining and utilizing a small part of coal combustion wastes.
6. Intermediate Temperature Fuel Cell Using Gypsum Based Electrolyte And Electrodes
International Nuclear Information System (INIS)
Suzuki, Satoshi; Nagai, Masayuki; Katagiri, Yuji
2011-01-01
The proton conductive electrolyte membrane and the electrodes for intermediate temperature fuel cell were made from the phosphoric acid treated gypsum as a proton conductor. The membrane and the electrodes were built into single cell and tested at intermediate temperature region. The power density of the fuel cell was 0.56 mW/cm -2 at 150 deg. C without any humidification and 1.38 mW/cm -2 at 150 deg. C, 5% relative humidity. The open circuit voltage of the cell was increased higher than 0.7 V when the electrodes were annealed at 150 deg. C, 5%R.H., however the reasons for this are still to be further investigated. The results show that the potential of the phosphoric acid treated gypsum for the intermediate temperature proton conductor.
7. Light Steel-Timber Frame with Composite and Plaster Bracing Panels
OpenAIRE
Scotta, Roberto; Trutalli, Davide; Fiorin, Laura; Pozza, Luca; Marchi, Luca; Stefani, Lorenzo De
2015-01-01
The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB) sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerica...
8. Biological sulfate removal from gypsum contaminated construction and demolition debris.
Science.gov (United States)
Kijjanapanich, Pimluck; Annachhatre, Ajit P; Esposito, Giovanni; van Hullebusch, Eric D; Lens, Piet N L
2013-12-15
9. Lime and gypsum application on the wheat crop
Directory of Open Access Journals (Sweden)
Caires Eduardo Fávero
2002-01-01
Full Text Available Root growth and crop yield can be affected by chemical modifications of the soil profile owing to lime and gypsum applications. A field trial was carried out on a dystrophic Clayey Rhodic Hapludox at Ponta Grossa, PR, Brazil, aiming to evaluate lime (without or with incorporation into the soil and gypsum effects on root growth, mineral nutrition and grain yield of wheat (cv. OR 1. A randomized complete block design was used, with three replications, in a split-plot experiment. Treatments with dolomitic limestone (without lime and 4.5 t ha-1 of lime applied on the surface, in total rate and 1/3 of the requirement per year during 3 years, or incorporated into the soil were applied in July 1998 (main plots and the rates of gypsum (0, 3, 6 and 9 t ha-1 in October 1998 (subplots. Wheat was evaluated in the 2000 winter season. In conditions of water deficit absence, there was no limitation in root growth in depth, for exchangeable Ca of 6 mmol c dm-3. Lime incorporation of lime increased the Mg concentration in the leaves, but wheat yield was not influenced by the correction of soil acidity through liming treatments. Gypsum increased the concentrations of Ca and S in wheat leaves, with significant effects on grain yield. The critical level of S-SO4(2- in the 0-20 cm soil layer, extracted by ammonium acetate 0.5 mol L-1 in acetic acid 0.25 mol L-1, was 25.8 mg dm-3.
10. occurrence and geochemistry of nafada gypsum, north-eastern nigeria
African Journals Online (AJOL)
DJFLEX
2010-03-18
Mar 18, 2010 ... The container was placed in a. “HERZOG” palletizing machine for 10 seconds after which a pellet was produced. The procedure was repeated for each gypsum sample. Each pellet was analyzed for SiO2, Al2O3, CaO, MgO, SO3, K2O, Na2O,. MgCO3, combine water and purity, using X-ray spectrometer.
11. Comparison of Energy Dissipation, Stiffness, and Damage of Structural Oriented Strand Board (OSB, Conventional Gypsum, and Viscoelastic Gypsum Shearwalls Subjected to Cyclic Loads
Directory of Open Access Journals (Sweden)
Andrew S. Blasetti
2012-06-01
Full Text Available A key element in the seismic load resisting system of a wood framed structure is the shear wall which is typically sheathed on one side with plywood or oriented strand board (OSB and gypsum on the other. The shear capacity of gypsum sheathed shear walls is typically neglected in high seismic areas due to the susceptibility of conventional drywall screw connections to damage caused by earthquakes. The earthquake resistance of an innovative viscoelastic (VE gypsum shearwall is evaluated and compared to conventional structural and non-structural walls. Ten 8 ft × 8 ft wood framed wall specimens of three configurations [nailed-OSB, screw-gypsum, and VE polymer-gypsum] were subjected to a cyclic test protocol. The energy dissipation, stiffness, and damage characteristics of all shearwalls are reported herein. Testing results indicate the VE-gypsum walls can dissipate more energy than the OSB structural panels and 500% more energy that the conventional gypsum sheathed walls and contains a constant source of energy dissipation not seen in the structural and non-structural walls. The wall stiffness of the OSB wall degrades at a far greater rate that the VE gypsum wall and at continued cycling degrades below the VE wall stiffness. Unlike both of the conventional wall types, the VE wall showed no visible or audible signs of damage when subjected to shear displacements up to 1.
12. Manufacturing of calcium phosphate scaffolds by pseudomorphic transformation of gypsum
Energy Technology Data Exchange (ETDEWEB)
Araujo Batista, H. de.; Batista Cardoso, M.; Sales Vasconcelos, A.; Vinicius Lia Fook, M.; Rodriguez Barbero, M. A.; Garcia Carrodeguas, R.
2016-08-01
Carbonated hydroxyapatite (CHAp) and β-tricalcium phosphate (β-TCP) have been employed for decades as constituents of scaffolds for bone regeneration because they chemically resemble bone mineral. In this study, the feasibility to manufacture CHAp/β-TCP scaffolds by pseudomorphic transformation of casted blocks of gypsum was investigated. The transformation was carried out by immersing the precursor gypsum block in 1 M (NH{sub 4}){sub 2}HPO{sub 4}/1.33 M NH{sub 4}OH solution with liquid/solid ratio of 10 mL/g and autoclaving at 120 degree centigrade and 203 kPa (2 atm) for 3 h at least. Neither shape nor dimensions significantly changed during transformation. The composition of scaffolds treated for 3 h was 70 wt.% CHAp and 30 wt.% β-TCP, and their compressive and diametral compressive strengths were 6.5 ± 0.7 and 5.3 ±0.7 MPa, respectively. By increasing the time of treatment to 6 h, the composition of the scaffold enriched in β-TCP (60 wt.% CHAp and 40 wt.% β-TCP) but its compressive and diametral compressive strengths were not significantly affected (6.7 ± 0.9 and 5.4 ± 0.6 MPa, respectively). On the basis of the results obtained, it was concluded that this route is a good approach to the manufacturing of biphasic (CHAp/β-TCP) scaffolds from previously shaped pieces of gypsum. (Author)
13. Sails: a new gypsum speleothem from Naica, Chihuahua, Mexico
Directory of Open Access Journals (Sweden)
Forti Paolo
2007-01-01
Full Text Available The caves of Naica (Chihuahua, Mexico are perhaps the most famous mine caves of the world due to the presence of giganticgypsum crystals. Nevertheless, very little research has been carried out on this karst area until now. A multidisciplinary investigationstarted in 2006 with the aim not only to define the genesis and the age of the Naica gypsum crystals, but also on other scientificaspects of these caves.This paper describes a completely new type of gypsum speleothem: the “sails”, observed only inside the Cueva de las Velas, one ofthe caves of the Naica system. This speleothem consists of extremely thin, elongated skeleton crystals that have grown epitaxiallyonly on the tips of the gypsum crystals pointing upward. The genesis of sails is strictly related to the environmental conditions setup inside the cave just after the artificial lowering of the groundwater by mine dewatering (less than 20 yr ago. In a few years sail speleothems will disappear entirely and therefore this study is fundamental to preserve at least the memory of them.
14. Crack Coalescence in Molded Gypsum and Carrara Marble
Science.gov (United States)
Wong, N.; Einstein, H. H.
2007-12-01
This research investigates the fracturing and coalescence behavior in prismatic laboratory-molded gypsum and Carrara marble specimens, which consist of either one or two pre-existing open flaws, under uniaxial compression. The tests are monitored by a high speed video system with a frame rate up to 24,000 frames/second. It allows one to precisely observe the cracking mechanisms, in particular if shear or tensile fracturing takes place. Seven crack types and nine crack coalescence categories are identified. The flaw inclination angle, the ligament length and the bridging angle between two flaws have different extents of influence on the coalescence patterns. For coplanar flaws, as the flaw inclination angle increases, there is a general trend of variation from shear coalescence to tensile coalescence. For stepped flaws, as the bridging angle changes from negative to small positive, and further up to large positive values, the coalescence generally progresses from categories of no coalescence, indirect coalescence to direct coalescence. For direct coalescence, it generally progresses from shear, mixed shear-tensile to tensile as the bridging angle increases. Some differences in fracturing and coalescence processes are observed in gypsum and marble, particularly the crack initiation in marble is preceded by the development of macroscopic white patches, but not in gypsum. Scanning Electron Microprobe (SEM) study reveals that the white patches consist of zones of microcracks (process zones).
15. The potential role of cattail-reinforced clay plaster in sustainable building
Directory of Open Access Journals (Sweden)
G. Georgiev
2014-06-01
Full Text Available Sustainable development is a key goal in town and country planning, as well as in the building industry. The main aims are to avoid inefficient land use, to improve the energy efficiency of buildings and, thus, to move towards meeting the challenges of climate change. In this article we consider how the use of a traditional low-energy building material, namely clay, might contribute. Recent research has identified a promising connection between the reinforcement of clay for internal wall plastering with fibres from the wetland plant Typha latifolia (cattail and the positive environmental effects of cultivating this species. If large quantities of Typha fibres were to be used in building, the need for cultivation of the plant would increase and create new possibilities for the renaturalisation of polluted or/and degraded peatlands. We explore the topic first on the basis of literature, considering the suitability of Typha for this application and possibilities for its sustainable cultivation, as well as implications for the life cycle analyses of buildings in which it is used. We then report (qualitatively the results of testing different combinations of clay with natural plant (straw and cattail fibres for their suitability as a universal plaster, which demonstrate clearly the superior properties of Typha fibres as a reinforcement material for clay plaster mortars.
16. Mud-plastered granary-baskets at a Celtic Oppidum near Čarnok (Vojvodina, Serbia
Directory of Open Access Journals (Sweden)
Medović Aleksandar
2011-01-01
Full Text Available In the Celtic Oppidum near Čarnok (Bačka, Vojvodina, Serbia remains of four mud-plastered granarybaskets were discovered. They are all dated to the period Gomolava VI-B (first half of the 1st century B.C.. Hulled barley and broomcorn millet were stored in the granary-baskets. The mesh of the granary-baskets was composed of young branches of oak tree (Quercus, common English elm tree (Ulmus cf. campestris L., poplar / willow (Populus / Salix, purgin buckthorn (Rhamnus cf. cathartica L., wayfaring tree (Viburnum cf. lantana L., spindle tree (Euonymus cf. europaeus L., barberry (Berberis vulgaris L. and a Pomoidae-tree. At least four different tree taxa were used for basket making. Construction of two-thousand-year old mud-plastered granary-baskets from the Pannonian plain is very similar to that of traditional granaries in some present-day villages in Africa. Additionally, one non-plastered basket was also discovered at Oppidum. It was build out of maple (Acer, barberry, buckthorn (Rhamnus and branches of a pomaceous fruits tree (Pomoidae. .
17. Objective assessment of plaster cast quality in pediatric distal forearm fractures: Is there an optimal index?
Science.gov (United States)
Labronici, Pedro José; Ferreira, Leonardo Termis; Dos Santos Filho, Fernando Claudino; Pires, Robinson Esteves Santos; Gomes, Davi Coutinho Fonseca Fernandes; da Silva, Luiz Henrique Penteado; Gameiro, Vinicius Schott
2017-02-01
Several so-called casting indices are available for objective evaluation of plaster cast quality. The present study sought to investigate four of these indices (gap index, padding index, Canterbury index, and three-point index) as compared to a reference standard (cast index) for evaluation of plaster cast quality after closed reduction of pediatric displaced distal forearm fractures. Forty-three radiographs from patients with displaced distal forearm fractures requiring manipulation were reviewed. Accuracy, sensitivity, specificity, false-positive probability, false-negative probability, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were calculated for each of the tested indices. Comparison among indices revealed diagnostic agreement in only 4.7% of cases. The strongest correlation with the cast index was found for the gap index, with a Spearman correlation coefficient of 0.94. The gap index also displayed the best agreement with the cast index, with both indices yielding the same result in 79.1% of assessments. When seeking to assess plaster cast quality, the cast index and gap index should be calculated; if both indices agree, a decision on quality can be made. If the cast and gap indices disagree, the padding index can be calculated as a tiebreaker, and the decision based on the most frequent of the three results. Calculation of the three-point index and Canterbury index appears unnecessary. Copyright © 2016 Elsevier Ltd. All rights reserved.
18. Influence of Curing Humidity on the Compressive Strength of Gypsum-Cemented Similar Materials
Directory of Open Access Journals (Sweden)
Weiming Guan
2016-01-01
Full Text Available The analogous simulation experiment is widely used in geotechnical and mining engineering. However, systematic errors derived from unified standard curing procedure have been underestimated to some extent. In this study, 140 gypsum-cemented similar material specimens were chosen to study their curing procedure with different relative humidity, which is 10%–15%, 40%, 60%, and 80%, respectively. SEM microstructures and XRD spectra were adopted to detect the correlation between microstructures and macroscopic mechanical strength during curing. Our results indicated that the needle-like phases of similar materials began to develop in the early stage of the hydration process through intersecting with each other and eventually transformed into mat-like phases. Increase of humidity may inhibit the development of needle-like phases; thus the compressive strength changes more smoothly, and the time required for the material strength to reach the peak value will be prolonged. The peak strength decreases along with the increase of humidity while the humidity is higher than 40%; however, the reverse tendency was observed if the humidity was lower than 40%. Finally, we noticed that the material strength usually reaches the peak value when the water content continuously reduces and tends towards stability. Based on the above observation, a curing method determination model and experimental strength predication method for gypsum-cemented similar materials were proposed.
19. Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples
Science.gov (United States)
Milsch, Harald; Priegnitz, Mike
2012-12-01
We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between 378 and 423 K. Dehydration did not proceed homogeneously but via a reaction front moving sample inwards separating an outer highly porous rim from the remaining gypsum which, above approximately 393 (±5) K, concurrently decomposed into hemihydrate. Overall porosity was observed to continuously increase with reaction progress from approximately 2% for fully hydrated samples to 30% for completely dehydrated ones. Concurrently, P and S-wave velocities linearly decreased with porosity from 5.2 and 2.7 km/s to 1.0 and 0.7 km/s, respectively. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.
20. Light in the darkening on Naica gypsum crystals
Energy Technology Data Exchange (ETDEWEB)
Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Esparza-Ponce, H. E.; Carreno-Márquez, J.; Montero-Cabrera, M. E., E-mail: [email protected] [Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua, Chih 31109, México (Mexico); Fuentes-Montero, M. E. [Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Campus Universitario#2, Circuito Universitario, C.P.31125, Chihuahua, Chih. México (Mexico); Reyes-Cortes, M. [Facultad de Ingeniería. Universidad Autónoma de Chihuahua, Campus Universitario#2, Circuito Universitario, C.P.31125, Chihuahua, Chih. México (Mexico)
2015-07-23
Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performed at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe{sub 2}O{sub 3}), β-MnO{sub 2}, Mn{sub 2}O{sub 3}, MnO and/or MnCO{sub 3}, PbS, PbCO{sub 3} and/or PbSO4, ZnO{sub 4}, ZnS and/or smithsonite (ZnCO{sub 3}), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases.
1. Light in the darkening on Naica gypsum crystals
International Nuclear Information System (INIS)
Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Esparza-Ponce, H. E.; Carreno-Márquez, J.; Montero-Cabrera, M. E.; Fuentes-Montero, M. E.; Reyes-Cortes, M.
2015-01-01
Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performed at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe 2 O 3 ), β-MnO 2 , Mn 2 O 3 , MnO and/or MnCO 3 , PbS, PbCO 3 and/or PbSO4, ZnO 4 , ZnS and/or smithsonite (ZnCO 3 ), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases
2. Nucleation and growth of the Naica giant gypsum crystals.
Science.gov (United States)
Otálora, Fermín; García-Ruiz, JuanMa
2014-04-07
The Cave of Giant Crystals in the Naica mine (Mexico) is one of the most amazing displays of mineral beauty ever created in nature. In addition to the colossal crystals of gypsum, which in some cases exceed eleven meters in length and one meter in thickness, the scenery fashioned by the crystalline beams that thrust through the darkness of the cave from floor to ceiling with a luster like moonlight is a unique example of harmony based on crystal symmetry. We review the crystallogenesis of this remarkable and challenging phenomenon of mineralization near equilibrium that can be used to teach the basics of nucleation and crystal growth.
3. POLYMER RESIDUE BASED HYDROPHOBIC-FUNGICIDAL ADDITIVE AND PLASTER DRY MIX BASED ON IT
Directory of Open Access Journals (Sweden)
Chikichev Artur Andreevich
2017-07-01
Full Text Available Subject of study is the effect of additives on the structure formation of cement. Improvement of the re-sistance to aggressive media of materials for wet rooms. Objective is to develop a scientifically grounded composition of a plaster dry construction mix with increased water resistance and funginertness, with the use of locally available materials and man-made waste.The study was carried out by standard methods of research using XRF and DTA. The hydrophobic fungicidal additive based on the polymer residue of turpentine production and fly ash with the ratio by weight ZU: PO = 1.15: 1 was developed. It has been established that while adding the de-veloped additive in an amount of 2.5 % of the mass of cement, the rate of hydration of cement minerals and resistibility of the sand-cement mortar decrease in early strength with medium workability concrete mix. This creates conditions for the formation of a dense structure with increased resistance to aggressive envi-ronments.Using new hydrophobic fungicidal additive, a dry plaster mortar for wet rooms has been developed. It has increased water resistance values corresponding to the W8 grade and funginertness especially with respect to A. Niger, the pathogen and widespread decomposer.The additive is effective; it is developed on the basis of industrial wastes and recycled materials. Its use in the composition of materials with increased requirements for watertightness and biostability makes it pos-sible to reduce their cost and environmental stress, to increase the efficiency of the use of natural re-sources. The use of the developed plaster mixture will increase the resistance of walls of wet rooms to aggressive environments.
4. Synthesis of partial stabilized cement-gypsum as new dental retrograde filling material
Energy Technology Data Exchange (ETDEWEB)
Sadhasivam, S. [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Division of Medical Engineering Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan (China); Chen, Jung-Chih [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Medical Device Innovation Center, National Cheng Kung University, Tainan,Taiwan (China); Savitha, S. [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Hsu, Ming-Xiang; Hsu, Chung-King [Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei, Taiwan (China); Lin, Chun-Pin [School of Dentistry and Graduate Institute of Clinical Dentistry, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei, Taiwan (China); Lin, Feng-Huei, E-mail: [email protected] [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Division of Medical Engineering Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan (China)
2012-10-01
The study describes the sol-gel synthesis of a new dental retrograde filling material partial stabilized cement (PSC)-gypsum by adding different weight percentage of gypsum (25% PSC + 75% gypsum, 50% PSC + 50% gypsum and 75% PSC + 25% gypsum) to the PSC. The crystalline phase and hydration products of PSC-gypsum were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The handling properties such as setting time, viscosity, tensile strength, porosity and pH, were also studied. The XRD and microstructure analysis demonstrated the formation of hydroxyapatite and removal of calcium dihydrate during its immersion in simulated body fluid (SBF) on day 10 for 75% PSC + 25% gypsum. The developed PSC-gypsum not only improved the setting time but also greatly reduced the viscosity, which is very essential for endodontic surgery. The cytotoxic and cell proliferation studies indicated that the synthesized material is highly biocompatible. The increased alkaline pH of the PSC-gypsum also had a remarkable antibacterial activity. - Highlights: Black-Right-Pointing-Pointer A new dental retrograde filling material PSC-gypsum was developed. Black-Right-Pointing-Pointer PSC-gypsum cement has shown excellent initial and final setting time as 15-35 min. Black-Right-Pointing-Pointer It not only improved the setting time but also retain the viscosity, 2 Pa{center_dot}s. Black-Right-Pointing-Pointer High alkaline pH of the cement had a remarkable antibacterial activity. Black-Right-Pointing-Pointer Cytotoxicity studies revealed that the synthesized material is highly biocompatible.
5. Compósitos à base de gesso com resíduos de EVA e vermiculita Gypsum-based composites with EVA waste and vermiculite
Directory of Open Access Journals (Sweden)
Marilia P. de Oliveira
2012-06-01
Full Text Available O gesso é um dos materiais de construção mais antigos de que se tem conhecimento. Algumas de suas propriedades lhes conferem vantagens, tais como resistência ao fogo e isolamentos térmico e acústico. Objetivou-se, com este trabalho, avaliar as propriedades físico-mecânicas de compósitos à base de gesso com a incorporação de resíduos da indústria de calçados, o etileno acetato de vinila (EVA e a vermiculita. O desenvolvimento desses compósitos tem como propósito a produção de elementos de revestimento para proteção térmica de alvenarias. Para determinar a influência dos teores de resíduo de EVA e vermiculita e da relação água/gesso nas propriedades massa específica aparente e nas resistências a flexão e a compressão, foram incorporados cinco diferentes percentuais desses materiais, combinados com três relações água/gesso. Os resultados foram analisados por meio da estatística multivariável e indicaram que a massa específica aparente de ambos os compósitos e a resistência à flexão do compósito com vermiculita, mostraram maior dependência da relação água/gesso; por sua vez, o percentual de agregado apresentou maior influência na resistência à flexão do compósito com EVA e na resistência a compressão de ambos os compósitos.Gypsum is one of the oldest known building materials. Some of its properties confer advantages such as fire resistance, thermal and acoustic insulation. This work aims to study the physical and mechanical properties of gypsum-based composite with the incorporation of residues from the footwear industry ethylene vinyl acetate (EVA and vermiculite. The aim to develop these composites is to produce components for thermal protection of masonry. To determine the influence of different residue levels of EVA and vermiculite, and the water/plaster ratio on the bulk density, flexural and compressive strength, five different percentages of these materials were incorporated combined with
6. A novel method for creating custom shaped ballistic gelatin trainers using plaster molds.
Science.gov (United States)
Doctor, Michael; Katz, Anne; McNamara, Shannon O; Leifer, Jessica H; Bambrick-Santoyo, Gabriela; Saul, Turandot; Rose, Keith M
2018-03-01
Simulation based procedural training is an effective and frequently used method for teaching vascular access techniques which often require commercial trainers. These can be prohibitively expensive, which allows for homemade trainers made of gelatin to be a more cost-effective and attractive option. Previously described trainers are often rectangular with a flat surface that is dissimilar to human anatomy. We describe a novel method to create a more anatomically realistic trainer using ballistic gelatin, household items, and supplies commonly found in an emergency department such as the plaster wrap typically used to make splints.
7. From alginate impressions to digital virtual models: accuracy and reproducibility.
Science.gov (United States)
Dalstra, Michel; Melsen, Birte
2009-03-01
To compare the accuracy and reproducibility of measurements performed on digital virtual models with those taken on plaster casts from models poured immediately after the impression was taken, the 'gold standard', and from plaster models poured following a 3-5 day shipping procedure of the alginate impression. Direct comparison of two measuring techniques. The study was conducted at the Department of Orthodontics, School of Dentistry, University of Aarhus, Denmark in 2006/2007. Twelve randomly selected orthodontic graduate students with informed consent. Three sets of alginate impressions were taken from the participants within 1 hour. Plaster models were poured immediately from two of the sets, while the third set was kept in transit in the mail for 3-5 days. Upon return a plaster model was poured as well. Finally digital models were made from the plaster models. A number of measurements were performed on the plaster casts with a digital calliper and on the corresponding digital models using the virtual measuring tool of the accompanying software. Afterwards these measurements were compared statistically. No statistical differences were found between the three sets of plaster models. The intra- and inter-observer variability are smaller for the measurements performed on the digital models. Sending alginate impressions by mail does not affect the quality and accuracy of plaster casts poured from them afterwards. Virtual measurements performed on digital models display less variability than the corresponding measurements performed with a calliper on the actual models.
8. Radiological properties of a wax-gypsum compensator material
International Nuclear Information System (INIS)
Plessis, F.C.P. du; Willemse, C.A.
2005-01-01
In this paper the radiological properties of a compensator material consisting of wax and gypsum is presented. Effective attenuation coefficients (EACs) have been determined from transmission measurements with an ion chamber in a Perspex phantom. Measurements were made at 80 and 100 cm source-to-skin distance (SSD) for beam energies of 6, 8, and 15 MV, for field sizes ranging from narrow beam geometries up to 40x40 cm 2 , and at measurement depths of maximum dose build-up, 5 and 10 cm. A parametrization equation could be constructed to predict the EAC values within 4% uncertainty as a function of field size and depth of measurement. The EAC dependence on off-axis position was also quantified at each beam energy and SSD. It was found that the compensator material reduced the required thickness for compensation by 26% at 8 MV when compared to pure paraffin wax for a 10x10 cm 2 field. Relative surface ionization (RSI) measurements have been made to quantify the effect of scattered electrons from the wax-gypsum compensator. Results indicated that for 80 cm SSD the RSI would exceed 50% for fields larger than 15x15 cm 2 . At 100 cm SSD the RSI values were below 50% for all field sizes used
9. Incorporation of arsenic into gypsum: Relevant to arsenic removal and immobilization process in hydrometallurgical industry
Energy Technology Data Exchange (ETDEWEB)
Zhang, Danni; Yuan, Zidan [Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Shaofeng, E-mail: [email protected] [Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Jia, Yongfeng, E-mail: [email protected] [Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Demopoulos, George P. [Department of Mining and Materials Engineering, McGill University, Montreal, QC H3A 2B2 (Canada)
2015-12-30
Highlights: • Quantitatively studied the incorporation of arsenic into the structure of gypsum. • Arsenic content in the solid increased with pH and initial arsenic concentration. • Calcium arsenate phase precipitated in addition to gypsum at higher pH values. • The structure of gypsum and its morphology was altered by the incorporated arsenate. • The incorporated arsenate formed sainfeldite-like local structure in gypsum. - Abstract: Gypsum precipitates as a major secondary mineral during the iron-arsenate coprecipitation process for the removal of arsenic from hydrometallurgical effluents. However, its role in the fixation of arsenic is still unknown. This work investigated the incorporation of arsenic into gypsum quantitatively during the crystallization process at various pHs and the initial arsenic concentrations. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray absorption near edge spectroscopy (XANES) and scanning electron microscopy (SEM) were employed to characterize the coprecipitated solids. The results showed that arsenate was measurably removed from solution during gypsum crystallization and the removal increased with increasing pH. At lower pH where the system was undersaturated with respect to calcium arsenate, arsenate ions were incorporated into gypsum structure, whereas at higher pH, calcium arsenate was formed and constituted the major arsenate bearing species in the precipitated solids. The findings may have important implications for arsenic speciation and stability of the hydrometallurgical solid wastes.
10. Authigenic gypsum in a deep sea core from Southeastern Arabian Sea
Digital Repository Service at National Institute of Oceanography (India)
Guptha, M.V.S.
Authigenic gypsum has been encountered in a deep sea core RC9-157 from the southeastern Arabian Sea at a depth of 4111 m which is a zone of lysocline. The formation of gypsum in the deep sea region is attributed to the prevailing sulphate rich...
11. Hydrology of marginal evaporitic basins during the Messinian Salinity Crisis: isotopic investigation of gypsum deposits
Science.gov (United States)
El Kilany, Aida; Caruso, Antonio; Dela Pierre, Francesco; Natalicchio, Marcello; Rouchy, Jean-Marie; Pierre, Catherine; Balter, Vincent; Aloisi, Giovanni
2016-04-01
The deposition of gypsum in Messinian Mediterranean marginal basins is controlled by basin restriction and the local hydrological cycle (evaporation/precipitation rates and relative importance of continental vs marine water inputs). We are using the stable isotopic composition of gypsum as a proxy of the hydrological cycle that dominated at the moment of gypsum precipitation. We studied the Messinian Caltanissetta (Sicily) and Tertiary Piedmont (north western Italy) basins where we carried out a high-resolution isotopic study of gypsum layers composing gypsum-marl cycles. These cycles are thought to be the sedimentary expression of astronomical precession cycles, lasting approximately 20 kyr, during which the marginal basins experienced a succession of arid and a wet conditions. We determined the isotopic composition of gypsum hydration water (18O and D), of the sulphate ion (34S, 18O) and of Strontium (87/86Sr), all of which are potentially affected by the hydrological cycle. In our samples, the mother water from which gypsum precipitated is considerably lighter (-4.0 micro-scale. This is an essential step in interpreting the isotopic signals of gypsum because we can expect the 18O and D composition of Messinian continental input to be not too dissimilar from that of modern meteoric waters involved in diagenetic processes.
12. The Growth of Gypsum in the Presence of Hexavalent Chromium: A Multiscale Study
Directory of Open Access Journals (Sweden)
Juan Morales
2016-03-01
Full Text Available The sorption of dissolved inorganic pollutants into the structure of minerals is an important process that controls the mobility and fate of these pollutants in the Earth’s crust. It also modifies the surface structure and composition of the host mineral, affecting its crystallization kinetics. Here, we investigate the effect of hexavalent chromium, Cr(VI, on the nucleation and growth of gypsum by conducting two types of experiments: (i in situ atomic force microscopy (AFM observations of the growth of gypsum {010} surfaces in the presence of Cr(VI and (ii gypsum precipitation experiments by mixing aqueous solutions containing variable amounts of Cr(VI. Gypsum precipitation is progressively delayed when occurring from solutions bearing increasing Cr(VI concentrations. Chemical analyses of gypsum precipitates show that gypsum incorporates small Cr(VI amounts that correlate with the content of this ion in the aqueous solution. Gypsum cell parameters variation reflects this incorporation. At the molecular scale, Cr(VI induces a slowdown of step advance rates on gypsum {010} surfaces accompanied by the roughening of nanostep edges and the so-called “template effect”. This effect involves the reproduction of the original nanotopography after the completion of individual advancing monolayers and appears as a general nanoscale phenomenon occurring during growth of solid solutions from aqueous solutions even in the case of compositionally-restricted solid solutions.
13. Pre-contamination of new gypsum wallboard with potentially harmful fungal species
DEFF Research Database (Denmark)
Andersen, Birgitte; Dosen, Ina; Lewinska, Anna Malgorzata
2017-01-01
Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine whether Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already...
14. Thermal conductivity of gypsum plasterboards : at ambient temperature and exposed to fire
NARCIS (Netherlands)
Korte, de A.C.J.; Brouwers, H.J.H.; Wald, F.; Kallerova, P.; Chlouba, J.
2009-01-01
One of the more complicated thermal properties to calculate for gypsum plasterboard is the thermal conductivity. The thermal conductivity is important because it plays an important role in the fire behaviour of gypsum plasterboards. Plasterboard often protects steel structures of buildings, because
15. Use of FGD gypsum on a bermudagrass pasture in the Appalachian Plateau Region
Science.gov (United States)
Addition of industrial by-products from coal fired power plants (FGD gypsum and FGD gypsum + fly ash) are thought to increase plant production. Thus, a study was conducted to evaluate the effects of industrial by-products as a soil amendment on bermudagrass (Cynodon dactylon L.) yield. The study was...
16. Natural radioactivity of the cement, lime and plaster in the Zacatecas State
International Nuclear Information System (INIS)
Mireles, F.; Davila, J. I.; Lopez, H.; Pinedo, J. L.; Rios, C.; Saucedo, S. A.; Cespedes, N.
2012-10-01
17. Plastering mortar with antibacterial and antifungal properties studied by 1H NMR relaxometry
Science.gov (United States)
Jumate, E.; Aciu, C.; Manea, D. L.; Moldovan, D.; Chelcea, R.; Fechete, R.
2017-12-01
The Plastering mortars, with good antibacterial (in particular Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa) and antifungal (Aspergillus niger and Penicillium chrysogenum) properties, were studied by 1D NMR relaxometry and internal humidity measurements. Three recipes based on plastering mortar with variable content (0, 5 and 10 %) of Ag/ZnO nanopowders and with adequate physical characteristics regarding the mechanical strengths (CS IV), good adhesion to the substrate and low water absorption by capillarity (W2) were considered. The distributions of transverse relaxation times T2 were measured at 2 h after preparation (for mortar pasta) and then for the same samples at 2, 7, and 28 days during the hydration of mineralogical components. The T2 distributions are characterized by four components associated with hydration water and water in three types of pores of different dimension. The dimension of pores formed during hydration process are strongly dependent on the Ag/ZnO nanopowders content but finally at 28 days the pores distributions, as resulted from the T2 distributions, looks similar. Finally, the transverse relaxation ratio was linearly correlated to the compressive strength and the hydration behaviour during 132 days measured with a dedicated humidity sensor embedded inside sampled was discussed.
18. ESR Studies and Dating of Egyptian Gypsum at Ras Mala'ab, Sinai, Egypt
International Nuclear Information System (INIS)
Abdel-Monem, A. A.; Abdei-Razek, Y. A.; Rasheed, N. M.; Hassan, G.M.; Eissa, H.M.; El-Morsy, M.
2007-01-01
A gypsum sample from the famous gypsum-anhydrite evaporitic deposit composing the Ras Mala'ab Formation, Upper Miocene, occurring at Ras Mala'ab, on the east coast of the Gulf of Suez, was subjected to (ESR) dosimetric studies. Also, (ESR) was used to date the formation or most recent recrystallization of that gypsum. The gypsum derivative (ESR) spectrum is characterized by the large broad Fe 2+ signal (g=2.50) and HF-sixtet Mn 2+ signals. Only the characteristic gypsum signal (G l, g=2.0040) was detected between the third and fourth lines of the HF-Mn 2+ which is attributed to the electron-center SO 3 - . This signal was sensitive to artificial γ-irradiation and showed significant enhancement using a γ-dose of 550 Gy. Also, the signal was very stable up to 400 o C. The gypsum sample with a total dose (TD) of 1500 Gy, determined graphically by extrapolating the linear relationship between defect concentration and the artificial γ-doses for (G l, g=2.0040) and an annual dose (D) due to cosmic rays (0.3 mGy), yielded an age of 5.00 Ma. This could mean the age of formation or latest recrystallization of this gypsum deposit. The geologic age assignment of the Ras Mala'ab Group including the evaporitic gypsum unit, is Middle to Late Miocene. It is directly overlain by the Pliocene elastics at the locality of Ras Mala'ab. This might suggest that these evaporitic gypsum facies represent the top of the Miocene in the Gulf of Suez area, since the Miocene-Pliocene boundary is now put at 5.00-5.50 Ma ago. Therefore, the ESR age of the Ras Mala'ab gypsum is consistent with the geologic age assignment
19. Hydrate Phase Assemblages in Blends of Ye'elimite and Gypsum with Alite and Belite
DEFF Research Database (Denmark)
Pedersen, Malene Thostrup; Skibsted, Jørgen
2016-01-01
Calcium sulpho-aluminate (CSA) cements all contain ye’elimite, either as the main phase or in intermediate amounts, while they differ in their content of accessory phases. Belite is the main phase in most CSA cements, however, alite - CSA cements have been produced. The hydrate phases formed during...... and hydration kinetics. The improved understanding of the hydrate phase assemblages as well as the hydration kinetics for the model systems will form the fundamental basis for further optimizations of blended systems including ye’elimite with the aim of maximizing the reaction degree of the main clinker phases...... hydration of CSA cements depend on the type of CSA cement and the amount of gypsum added. The hydration reactions of the main phases are by themselves well documented, whereas the simultaneous hydration of CSA cement components is not fully understood in terms of hydration products and kinetics. To further...
20. Experimental and theoretical determination of the absorption coefficients of X-rays through barium plaster from 100 to 400 keV
International Nuclear Information System (INIS)
Joksimovicj, V.
1976-01-01
The absorption coefficients of X-rays from 100 to 400 keV through barium plaster of equivalent atomic number of 26 have been determined experimentally and theoretically. Calculated values are compared with experimental data. Matrix components of barium plaster were determined chemically and by X-ray fluorescence
1. Towards understanding the influence of porosity on mechanical and fracture behaviour of quasi-brittle materials : Experiments and modelling
NARCIS (Netherlands)
Liu, D; Savija, B.; Smith, G.E.; Flewitt, P.E.J.; Lowe, T.; Schlangen, H.E.J.G.
2017-01-01
In this work, porosity-property relationships of quasi-brittle materials are explored through a combined experimental and numerical approach. In the experimental part, hemihyrate gypsum plaster powder (CaSO 4 ⋅1/2H 2 O CaSO4⋅1/2H2O) and expanded spherical polystyrene beads (1.5–2.0 mm dia.) have
2. Constructive applications of composite gypsum reinforced with Typha Latifolia fibres
Directory of Open Access Journals (Sweden)
Garcia Santos, A.
2004-03-01
Full Text Available The present research analyses the possibility to reinforce gypsum using enea fibres (Typha Latifolia creating a compound material in wich the fibres contribute to increase mechanical resistance, producing as well a reduction of the weight and a possible regulation of the set time.
La investigación presente analiza la posibilidad de reforzar los morteros de escayola mediante la utilización dé fibras de Typha Latifolia, creando un material compuesto en el que las fibras contribuyen al aumento de resistencia mecánica, a la vez que se produce una reducción del peso y una regulación de los tiempos de fraguado. Las propiedades de estos materiales hacen que, en determinadas aplicaciones, su utilización resulte ventajosa con respecto a materiales tradicionales.
3. Optically stimulated luminescence dosimetry with gypsum wallboard (drywall)
International Nuclear Information System (INIS)
Thompson, J. W.; Burdette, K. E.; Inrig, E. L.; Dewitt, R.; Mistry, R.; Rink, W. J.; Boreham, D. R.
2010-01-01
Gypsum wallboard (drywall) represents an attractive target for retrospective dosimetry by optically stimulated luminescence (OSL) in the event of a radiological accident or malicious use of nuclear material. In this study, wallboard is shown to display a radiation-induced luminescence signal (RIS) as well as a natural background signal (NS), which is comparable in intensity to the RIS. Excitation and emission spectra show that maximum luminescence intensity is obtained for stimulation with blue light-emitting diodes (470 nm) and for detection in the ultraviolet region (290-370 nm). It is necessary to decrease the optical stimulation power dramatically in order to adequately separate the RIS from the interfering background signal. The necessary protocols are developed for accurately measuring the absorbed dose as low as 500 mGy and demonstrate that the RIS decays logarithmically with storage time, with complete erasure expected within 1-4 d. (authors)
4. Efficacy and safety assessment of acute sports-related traumatic soft tissue injuries using a new ibuprofen medicated plaster: results from a randomized controlled clinical trial.
Science.gov (United States)
Predel, Hans-Georg; Connolly, Mark P; Bhatt, Aomesh; Giannetti, Bruno
2017-11-01
To investigate the efficacy and safety of a recently developed ibuprofen medicated plaster in the treatment of acute sports impact injuries/contusions. In this double-blind, multi-center, placebo-controlled, parallel group, phase 3 study (EudraCT Number: 2012-003257-2) patients (n = 132; ages 18 to 60 years) diagnosed with acute sports-related traumatic blunt soft tissue injury/contusion to the upper or lower limbs were randomized to receive either ibuprofen 200 mg plaster (n = 64) or placebo plaster (n = 68). Plasters were administered once daily for five consecutive days. The primary assessment was the area under the curve (AUC) of the visual analogue scale (VAS) of pain on movement (POM) over 0 to 72 h (VAS 0-72 ). The ibuprofen medicated plaster was associated with a reduction in pain on movement (POM) based on lower VAS AUC 0-72h (2399.4 mm*h) compared with placebo (4078.9 mm*h) (least squares mean difference: - 1679.5 mm*h; P ibuprofen medicated plaster compared with placebo at 12, 48, 24, and 120 h (P ibuprofen medicated plaster was associated with greater reduction in tenderness/pain than placebo at each timepoint (P values ibuprofen plaster, and n = 6 [8.8%] for placebo). All drug-related AEs were administration site reactions and were mild in intensity. The results of this study indicate that ibuprofen medicated plaster results in rapid and clinically relevant reduction of pain in patients suffering from blunt musculoskeletal injuries or recurrent pain. The ibuprofen medicated plaster was well tolerated.
5. Functional treatment versus plaster for simple elbow dislocations (FuncSiE: a randomized trial
Directory of Open Access Journals (Sweden)
Verleisdonk Egbert JMM
2010-11-01
Full Text Available Abstract Background Elbow dislocations can be classified as simple or complex. Simple dislocations are characterized by the absence of fractures, while complex dislocations are associated with fractures. After reduction of a simple dislocation, treatment options include immobilization in a static plaster for different periods of time or so-called functional treatment. Functional treatment is characterized by early active motion within the limits of pain with or without the use of a sling or hinged brace. Theoretically, functional treatment should prevent stiffness without introducing increased joint instability. The primary aim of this randomized controlled trial is to compare early functional treatment versus plaster immobilization following simple dislocations of the elbow. Methods/Design The design of the study will be a multicenter randomized controlled trial of 100 patients who have sustained a simple elbow dislocation. After reduction of the dislocation, patients are randomized between a pressure bandage for 5-7 days and early functional treatment or a plaster in 90 degrees flexion, neutral position for pro-supination for a period of three weeks. In the functional group, treatment is started with early active motion within the limits of pain. Function, pain, and radiographic recovery will be evaluated at regular intervals over the subsequent 12 months. The primary outcome measure is the Quick Disabilities of the Arm, Shoulder, and Hand score. The secondary outcome measures are the Mayo Elbow Performance Index, Oxford elbow score, pain level at both sides, range of motion of the elbow joint at both sides, rate of secondary interventions and complication rates in both groups (secondary dislocation, instability, relaxation, health-related quality of life (Short-Form 36 and EuroQol-5D, radiographic appearance of the elbow joint (degenerative changes and heterotopic ossifications, costs, and cost-effectiveness. Discussion The successful
6. Influence of gypsum amendment on methane emission from paddy rice soil affected by saline irrigation water
Directory of Open Access Journals (Sweden)
Ei Ei eTheint
2016-01-01
Full Text Available To investigate the influence of gypsum application on methane (CH4 emission from paddy rice soil affected by saline irrigation water, two pot experiments with the rice cultivation were conducted. In pot experiment (I, salinity levels 30 mMNaCl (S30 and 90 mMNaCl (S90, that showed maximum and minimum CH4 production in an incubation experiment, respectively, were selected and studied without and with application of 1 Mg gypsum ha-1(G1. In pot experiment (II, CH4 emission was investigated under different rates of gypsum application: 1 (G1, 2.5 (G2.5 and 5 (G5 Mg gypsum ha-1 under a non-saline and saline condition of 25 mMNaCl (S25. In experiment (I, the smallest CH4 emission was observed in S90. Methane emission in S30 was not significantly different with the non-saline control. The addition of gypsum showed significant lower CH4 emission in saline and non-saline treatments compared with non-saline control. In experiment (II, the CH4 emissions in the saline treatments were not significantly different to the non-saline treatments except S25-G5. However, our work has shown that gypsum can lower CH4 emissions under saline and non-saline conditions. Thus, gypsum can be used as a CH4 mitigation option in non-saline as well as in saline conditions.
7. Use of gypsum residues as a corrective for saline-sodic soil
Directory of Open Access Journals (Sweden)
Paulo Medeiros dos Santos
2014-03-01
Full Text Available One of the hugest problems faced by the civil construction sector is the final destination of residues, especially gypsum, which presents recycling restrictions. However, these residues present a high amount of calcium in their composition, and can be alternatively used for replacing mined gypsum as a saline-sodic soil corrective. This study aimed at evaluating the efficiency of gypsum residues from the civil construction, when compared to mined gypsum, for correcting a saline-sodic soil. A randomized blocks design was used, in a factorial arrangement consisting of two kinds of corrective (gypsum residue and mined gypsum and five leaching depths (0.5, 1.0, 1.5, 2.0 and 2.5 times the soil pores volume, with three replications. Electric conductivity, soluble cations and sodium adsorption ratio were evaluated in the soil saturation extract. The use of gypsum residue proved to be effective in leaching salts and soluble sodium in saline-sodic soil, and can be recommended as a calcium source for recovering from sodicity.
8. Initiation and growth of gypsum piercement structures in the Zechstein Basin
Science.gov (United States)
Williams-Stroud, S. C.; Paul, J.
1997-01-01
The importance of tectonic processes in initiating halite diapirs has become much better understood in recent years. Less well understood is the development of diapiric structures involving rocks composed predominantly of gypsum. Below about 1000 m, gypsum dehydrates to anhydrite, which often obscures primary sedimentary textures. If the strain associated with diapiric rise in the rock induces the transition to anhydrite, obliteration of primary features in the gypsum can be expected. In our study, we infer that the diapiric movement in the Werra Anhydrite member of cycle 1 of the Zechstein Formation of Europe occurred before the initial transition of gypsum to anhydrite based on the presence of pseudomorphs of bedded primary gypsum crystals, the overburden lithologies and depositional environment, and the mechanical properties of gypsum, anhydrite and carbonate rocks. Faulting and differential loading of a shallow overburden were the key components in initiating the gypsum diapirism. The transition to anhydrite occurred after burial and after cessation of diapirism. In comparison, the diapirism of calcium sulfate of the Leine Anhydrite into the Leine Halite members of cycle 3 of the Zechstein Formation probably occurred much later after burial and appears to have been triggered by halite diapirism, which in turn triggered the dehydration reaction, causing the calcium sulfate to become the incompetent phase relative to the halite. Published by Elsevier Science Ltd.
9. UTILIZATION OF MINERAL FIBER WASTE IN THE PRODUCTION OF GYPSUM PRODUCTS
Directory of Open Access Journals (Sweden)
Solov'ev Vitaliy Nikolaevich
2018-01-01
Full Text Available Subject: the effectiveness of using compositions with the use of basalt fibers is proven, but the composition must be selected depending on the binder and additives chosen. Research objectives: we examine the possibility of waste recycling of basalt fiber production during manufacturing of modified gypsum composite material with improved characteristics. Materials and methods: as a raw material, a gypsum binder of Samara production was used. As a reinforcement additive, a disperse waste of basalt fiber production of Tver region was used. Studying characteristics of the gypsum binder and modified mixture, and also comparative analysis of these characteristics by average density, total porosity, strength in compression and flexure of the gypsum composite were carried out using standard techniques. Results: dependence of physical and mechanical properties of the modified gypsum material on the content of the basalt fiber additive is established. It was found that an increase in concentration of the additive requires an increased water content or additional use of plasticizer. Conclusions: modification of gypsum stone with a mineral basalt additive will increase the strength, density and durability of thin-walled gypsum products, and, consequently, the demand for products due to ensuring their high quality in transportation and installation.
10. Early mobilisation versus plaster immobilisation of simple elbow dislocations: Results of the FuncSiE multicentre randomised clinical trial
NARCIS (Netherlands)
G.I.T. Iordens (Gijs); E.M.M. van Lieshout (Esther); N.W.L. Schep (Niels); J. de Haan (Jeroen); W.E. Tuinebreijer (Wim); D. Eygendaal (Denise); E.F. van Beeck (Ed); P. Patka (Peter); M.H.J. Verhofstad (Michiel); D. den Hartog (Dennis); R.S. Breederveld (Roelf S.); M.W.G.A. Bronkhorst (Maarten); M.R. de Vries (Mark); B.J. Dwars (Boudewijn); R. Haverlag (Robert); S.A.G. Meylaerts (Sven); J.W. Mulder (Jan-Willem); K.J. Ponsen (Kees-jan); W.H. Roerdink (Herbert); G.R. Roukema (Gert); I.B. Schipper (Inger); M.A. Schouten (Michel); J.B. Sintenie (Jan Bernard); S. Sivro (Senail); J.G.H. van den Brand (Johan); F.M. van der Linden (Frits); H.G.W.M. Meulen (Hub); E.J.M.M. Verleisdonk (Egbert); J.P.A.M. Vroemen (Jos); M. Waleboer (Marco); W.J. Willems (Jaap)
2017-01-01
textabstractBackground/aim To compare outcome of early mobilisation and plaster immobilisation in patients with a simple elbow dislocation. We hypothesised that early mobilisation would result in earlier functional recovery. Methods From August 2009 to September 2012, 100 adult patients with a
11. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils
Science.gov (United States)
Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe
2015-01-01
Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038
12. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils.
Science.gov (United States)
Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe
2015-06-01
Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline-alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation.
13. Lead Equivalent Thickness Measurement for Mixed Compositions of Barium Plaster Block
International Nuclear Information System (INIS)
Norriza Mohd Isa; Muhammad Jamal Muhammad Isa; Nur Shahriza Zainuddin; Mohd Khairusalih Md Zin; Shahrul Azlan Azizan
2016-01-01
Measurement of lead equivalent thickness for ionizing radiation exposure room wall shall be performed as stated in Malaysian Standard MS 838. A few numbers of sample blocks with different mixture of barium plaster compositions based and varies certain thickness as a shielding material for exposure room wall belong to a local company were tested by using Cs-137, Co-60 and Am-241 with different activities . Radiations passed through the samples were detected with calibrated survey meter. The distance between radiation source and the detector is about 40 cm. Lead uniformity test on the samples was also determined at three labeled points on the samples. Lead equivalent thicknesses for the samples were evaluated based on a calibration graph that was plotted with lead sheets and with the radiation sources. Results shown that lead equivalent thickness for the samples with same actual physical thickness represent different values for different sources. (author)
14. A Photodegradation Study of Three Common Paint and Plaster Biocides under monochromatic UV Light
DEFF Research Database (Denmark)
Minelgaite, Greta; Vollertsen, Jes; Nielsen, Asbjørn Haaning
2014-01-01
Photodegradation of the three common paint-and-plaster biocides (carbendazim, diuron and terbutryn) was investigated at controlled laboratory conditions. Samples prepared in two types of water (demineralized water and pond water) were subjected to 254 nm monochromatic UV light. Light intensity (W m......-2) in the experimental chamber was measured by a fiber optic spectrometer. The observed decline in biocide concentration was related with the light energy, accumulated during the time of degradation (kJ m-2), and 1st order photodegradation rate constants (m2 kJ-1) were determined. The obtained...... at selected laboratory conditions, as well as emphasize the importance of water type when investigating pollutant’s photo fate, as certain constituents might act as reaction enhancers or inhibitors....
15. Influence of shelf life on the setting time of type IV gypsum
Science.gov (United States)
Hapsari, M. L.; Irawan, B.; Damiyanti, M.
2017-08-01
Although expired materials can exhibit a deterioration in their properties, expired type IV gypsum can still be found on the market. In order to evaluate the influence of the shelf life on its setting time, two groups of type IV gypsum (GC Fuji rock EP) with different expiration dates were used in this research. The setting time tests were done in a mold using a Vicat Needle apparatus. The results of the statistical analysis showed a significant difference (pshelf life did influence the setting time of the type IV gypsum.
16. Investigation of the gypsum quality at three full-scale wet flue gas desulphurisation plants
DEFF Research Database (Denmark)
Hansen, Brian Brun; Kiil, Søren; Johnsson, Jan Erik
2011-01-01
In the present study the gypsum (CaSO4·2H2O) quality at three full-scale wet flue gas desulphurisation (FGD) plants and a pilot plant were examined and compared. Gypsum quality can be expressed in terms of moisture content (particle size and morphology dependent) and the concentration of residual......, low moisture content and low impurity content). An episode concerning a sudden deterioration in the gypsum dewatering properties was furthermore investigated, and a change in crystal morphology, as well as an increased impurity content (aluminium, iron and fluoride), was detected....
17. Determination of Radium 226 in mexican phosphate fertilizers and gypsum by gamma spectrometry
International Nuclear Information System (INIS)
Godinez A, M.C.
1995-01-01
The 226 Ra isotope was determined in 17, 20 and 46% m/m phosphate fertilizers and gypsum. The samples of the fertilizers were dissolved in 10% v/v nitric acid solutions. The barium sulphate method was used for the precipitation of 226 Ra. On the other hand, alkaline fusion method was used to separate the 226 Ra from gypsum. The results indicated that 226 Ra was present in the phosphate fertilizers and gypsum. The 226 Ra concentrations present in these materials were between 10 -4 - 10 -5 μg g -1 . (Author)
18. The effect of disinfection of alginate impressions with 35% beetle juice spray on stone model linear dimensional changes
Directory of Open Access Journals (Sweden)
2007-07-01
Full Text Available Dimensional stability of alginate impression is very important for treatment in dentistry. This study was to find the effect of the beetle juice spray procedure on alginate impression on gypsum model linear dimensional changes. This experimental study used 25 samples, divided into 5 groups. The first group, as control, were the alginate impressions filled with dental stone immediately after forming. The other four groups were the alginate impressions gel spray each 1,2,3, and 4 times with 35% beetle juice and then filled with dental stone. Dimensional changes were measured in the lower part of the plaster model from buccal-lingual and mesial-distal direction and also measured in the outer distance between the upper part of the stone model by using Mitutoyo digital micrometre and profile projector scaled 0,001 mm. The results of mesial-distal diameter average of the control group and group 2,3,4, and 5 were 9.909 mm, 9.852 mm, 9.845 mm, 9.824 mm, and 9.754 mm. Meanwhile, the results of buccal-lingual diameter average were 9.847 mm, 9.841 mm, 9.826 mm, 9.776 mm, and 9.729 mm. The results of the outer distance between the upper part of the stone model were 31.739 mm, 31.689 mm, 31.682 mm, 31.670 mm, and 31.670 mm. The data of this study was evaluated statistically based on the variant analysis. The conclusion of this study was statistically, there was no significant effect on gypsum model linear dimensional changes obtained from alginate impressions sprayed with 35% beetle juice.
19. Gypsum-induced decay in granite monuments in Northwestern Spain
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Silva Hermo, B.
2010-03-01
Full Text Available One of the most common forms of decay in granite monuments is the detachment of the superficial layer of the stone (plaques, plaquettes and scales. Previous studies of granite monuments in the northwest Iberian Peninsula revealed a direct relation between this type of weathering and the presence of calcium sulphate, and a mechanism whereby the salt causes this type of decay was suggested. In the present study, various hypotheses as regards the origin of the gypsum found in granite monuments are proposed. The study involved analysis of the contents of ions soluble in water, the results of X-ray diffraction analyses and the ratios of CaO/SO3 in samples of stone, mortar and deposits collected from different monuments. It was concluded that in most cases the gypsum originated from old paintworks or/and from the joint mortars, although inputs from other sources cannot be discounted, as discussed
Una de las formas de deterioro más frecuente en los monumentos graníticos es la separación de la capa superficial de la piedra (placas, plaquetas y escamas. En trabajos anteriores centrados en monumentos del noroeste de la Península Ibérica, se constató la relación directa entre esta forma de alteración y la presencia de sulfato de calcio y se propuso el mecanismo a través del cual esta sal provoca este tipo de deterioro. En este trabajo se plantean varias hipótesis acerca del origen del yeso encontrado en monumentos graníticos. Para ello se comparan los contenidos de iones solubilizados en agua, los resultados de difracción de rayos X y las relaciones OCa/SO3 de muestras de piedra, morteros y depósitos recogidas en diferentes monumentos. Se llega a la conclusión de que en la mayor parte de los casos el yeso procede de antiguas pinturas o de revestimientos superficiales y de los morteros de juntas entre sillares, pero no se puede descartar la contribución de otros aportes, los cuales se discuten también en este artículo.
20. Primary Evaporites for the Messinian Salinity Crisis: the shallow gypsum vs. deep dolomite formation paradox solved
Science.gov (United States)
De Lange, Gert J.; Krijgsman, Wout
2014-05-01
The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, and resulted in the deposition of 0.3-3 km thick evaporites at the Mediterranean seafloor. A considerable and long-lasting controversy existed on the modes of their formation. During the CIESM Almeria Workshop a consensus was reached on several aspects. In addition, remaining issues to be solved were identified, such as for the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions. Gypsum precipitation only occurred at marginal settings, while dolomite containing rocks have been reported from deeper settings. A range of potential explanations have been reported, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are poorly understood and commonly neglected. These may, however, explain that different deposits formed in shallow versus deep environments without needing exceptional physical boundary conditions for each. We present here a unifying mechanism in which gypsum formation occurs at all shallow water depths but its preservation is mostly limited to shallow sedimentary settings. In contrast, ongoing anoxic organic matter (OM) degradation processes in the deep basin result in the formation of dolomite. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always largely oversaturated relative to dolomite but its formation is thought to be inhibited by the presence of dissolved sulphate. Thus the conditions for formation of gypsum exclude those for the formation of dolomite and vice versa. Another process that links the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, oxygen is rapidly depleted through OM degradation, then sulphate becomes the main oxidant for OM
1. Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard
Science.gov (United States)
This page contains documents related to the evaluation of coal combustion residual beneficial use of fly ash concrete and FGD gypsum wallboard including the evaluation itself and the accompanying appendices
2. Oxidation of North Dakota scrubber sludge for soil amendment and production of gypsum. Final report
Energy Technology Data Exchange (ETDEWEB)
Hassett, D.J.; Moe, T.A.
1997-10-01
Cooperative Powers Coal Creek Station (CCS) the North Dakota Industrial Commission, and the US Department of Energy provided funds for a research project at the Energy and Environmental Research Center. The goals of the project were (1) to determine conditions for the conversion of scrubber sludge to gypsum simulating an ex situ process on the laboratory scale; (2) to determine the feasibility of scaleup of the process; (3) if warranted, to demonstrate the ex situ process for conversion on the pilot scale; and (4) to evaluate the quality and handling characteristics of the gypsum produced on the pilot scale. The process development and demonstration phases of this project were successfully completed focusing on ex situ oxidation using air at low pH. The potential to produce a high-purity gypsum on a commercial scale is excellent. The results of this project demonstrate the feasibility of converting CCS scrubber sludge to gypsum exhibiting characteristics appropriate for agricultural application as soil amendment as well as for use in gypsum wallboard production. Gypsum of a purity of over 98% containing acceptable levels of potentially problematic constituents was produced in the laboratory and in a pilot-scale demonstration.
3. NOx photocatalytic degradation on gypsum plates modified by TiO2-N,C photocatalysts
Directory of Open Access Journals (Sweden)
Janus Magdalena
2015-09-01
Full Text Available In presented studies the photocatalytic decomposition of NOx on gypsum plates modified by TiO2-N,Cphotocatalysts were presented. The gypsum plates were obtained by addition of 10 or 20 wt.% of different types of titanium dioxide, such as: pure TiO2 and carbon and nitrogen co-modified TiO2 (TiO2-N,C to gypsum. TiO2-N,C photocatalysts were obtained by heating up the starting TiO2 (Grupa Azoty Zakłady Chemiczne Police S.A in the atmosphere of ammonia and carbon at the temperature: 100, 300 i 600ºC. Photocatalyst were characterized by FTIR/DRS, UVVis/DR, BET and XRD methods. Moreover the compressive strength tests of modified gypsum were also done. Photocatalytic activity of gypsum plates was done during NOx decomposition. The highest photocatalytic activity has gypsum with 20 wt.% addition of TiO2-N,C obtained at 300ºC.
4. Field studies with radioactive sulphur-labelled gypsum fertiliser
International Nuclear Information System (INIS)
Goh, K.M.; Gregg, P.E.H.
1982-01-01
Quantitative estimates of the sizes of different sulphur (S) cycling pools in the soil-pasture system have been determined in soils belonging to the recent and yellow-brown earth soil groups. Several field trials were conducted, involving applications of 35 S-labelled gypsum fertiliser. An equilibrium was attained in the specific activity of the pasture herbage at about 240 days after fertiliser application. This was used to estimate pool sizes. At all sites, the amount of S involved in cycling ranged from 105 to 292 kg S/ha, which was sufficiently large to sustain active plant growth if cycled rapidly. However, most of the S was in the inert fraction (80-90% of total soil S) which appeared not to enter the active S cycling pool. At 3 of the sites studied, the major contributor to the cycling S pool was the residues pool of plant residues and soil organisms. No relationship was found between the size of the cycling S pool and topdressing responses of pastures. The significance of the results obtained is discussed in relation to the availability of S to pasture plants. (auth)
5. Gypsum amendment to soil can reduce selenium uptake by alfalfa grown in the presence of coal fly ash
International Nuclear Information System (INIS)
Arthur, M.A.; Rubin, G.; Woodbury, P.B.; Weinstein, L.H.
1993-01-01
Experiments in the field and greenhouse were conducted in the presence of coal fly ash to determine whether gypsum can reduce Se concentration in alfalfa (Medicago sativa L.). In the field experiment, conducted at a coal fly ash landfill, 11.2 t ha -1 gypsum was applied to soil as a top dressing to test the effect of gypsum in reducing selenium (Se) concentration in aboveground plant tissue. There were four treatment combinations of gypsum over a two year period, 1990, and 1991: (0, 0), (0, 11.2) (11.2, 0) and (11.2, 11.2). In 1991, the Se concentration was lower in alfalfa grown with gypsum, regardless of whether the gypsum was applied in both years or in only one year, indicating that the effect of gypsum application in the first year persisted into the second year. Since there was no increase in aboveground biomass with added gypsum, differences in Se concentration reflect a competitive interaction between S and Se. In the greenhouse experiment, 12 soil treatments were tested: three levels of fly ash (0, 10 and 20%) in combination with each of four levels of gypsum (0, 2.5, 5 and 7.5%). The Se concentration in alfalfa grown in 10% fly ash declined linearly with increasing gypsum dose, resulting in a reduction in Se concentration of 0.04 ± 0.02 μg g -1 for each 1% gypsum added for the first harvest and 0.06 ± 0.03 μg g -1 for each 1% gypsum added in the second harvest. Based on these results, gypsum may prove useful as a management tool to reduce the uptake of Se by plants growing on coal fly ash landfills
6. Study of heat and mass transfer of water evaporation in a gypsum board subjected to natural convection
Science.gov (United States)
Zannouni, K.; El Abrach, H.; Dhahri, H.; Mhimid, A.
2017-06-01
The present paper reports a numerical study to investigate the drying of rectangular gypsum sample based on a diffusive model. Both vertical and low sides of the porous media are treated as adiabatic and impermeable surfaces plate. The upper face of the plate represents the permeable interface. The energy equation model is based on the local thermal equilibrium assumption between the fluid and the solid phases. The lattice Boltzmann method (LBM) is used for solving the governing differential equations system. The obtained numerical results concerning the moisture content and the temperature within a gypsum sample were discussed. A comprehensive analysis of the influence of the mass transfer coefficient, the convective heat transfer coefficient, the external temperature, the relative humidity and the diffusion coefficient on macroscopic fields are also investigated. They all presented results in this paper and obtained in the stable regime correspond to time superior than 4000 s. Therefore the numerical error is inferior to 2%. The experimental data and the descriptive information of the approach indicate an excellent agreement between the results of our developed numerical code based on the LBM and the published ones.
7. CHEMICAL SOIL ATTRIBUTES AS AFFECTED BY LIME AND GYPSUM SURFACE APPLICATION
Directory of Open Access Journals (Sweden)
A. Mantovani
2017-10-01
Full Text Available The gypsum is a soil condition end it has to function contribute to the elimination or reduction of aluminum in the soil in depth. Still, it can contribute to the distribution of nutrients in the soil profile more uniformly and thus increasing the productivity of crops. This study aimed to evaluate the influence of gypsum application, with and without lime, on soil chemical properties and soybean yield, in a no-till system. The experiment was carried in Campos Novos, Santa Catarina State, Brazil, with a randomized block design and split plot design with four replications, the main portion was distributed gypsum doses (1000, 2000, 4000 and 6000 kg ha-1 without incorporation, and the split plot (with and without lime and the liming was 2,000 kg ha-1. We evaluated the performance of components and productivity of soybeans. It was also analyzed the soil pH and Ca, Mg, S and Al at 0-20 and 20-40 cm. The application of gypsum at the rates tested surface with and without lime did not affect the yield components and soybean productivity. At 0-20 cm soil depth lime application increased soil pH by 0.3 units on the average rates of gypsum, but in the 20-40 cm layer was not found effect of lime and gypsum in pH ground due to the short time between application and evaluation. In areas with and without lime contents of Ca and S in the two layers evaluated increased with increasing rates of gypsum, since Mg has difference with the lime application on a 0-20 cm to dose 4000 kg ha-1 and the lime in the gypsum rates and Al decreased with increasing dose gypsum average in the 20-40 cm layer depth. The application of gypsum and limestone softened the negative effects of soil acidity and the increase mainly of calcium and sulfur at 0-20 cm, with less efficient effects in the 20-40 cm layer due to the soil is clayey and the period between the implementation and evaluation be 120 days.
8. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder
International Nuclear Information System (INIS)
Zhong Shiyun; Ni Kun; Li Jinmei
2012-01-01
Highlights: ► The mortar with uncalcined FGD gypsum has suitable workability. ► The strength of mortar with uncalcined FGD gypsum is higher than that of mortar without uncalcined FGD gypsum. ► The dry shrinkage of mortar with uncalcined FGD gypsum is lower than that of mortar without uncalcined FGD gypsum. ► The leaching of sulfate ion of mortar is studied. - Abstract: A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C–S–H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563–938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO 4 2- from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO 4 2- releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO 4 2- from the mortar with 20% FGD gypsum is 9200 mg·m −2 , which is lower than that from the mortar with 95% cement clinker and 5% FGD gypsum.
9. New exergy criterion in the 'multi-criteria' context: a life cycle assessment of two plaster products
International Nuclear Information System (INIS)
Beccali, Giorgio; Cellura, Maurizio; Mistretta, Marina
2003-01-01
This paper deals with the exergy analysis (EXA) of plaster materials and ranks the environmental burdens due to the production of such materials. The calculation of the exergy loss during the whole examined process represents a relevant index, looking at the technology improvement of a process, as a suitable tool in aid of the trade-off of alternative materials in the decision making. A life cycle inventory is performed for building plaster products and the matrix method is used. The authors extend the application of EXA to life cycle assessment, conducting an exergetic life cycle assessment, and propose an exergetic index in the framework of multi-criteria decision making. An exergy balance, accounting for energy and material flows, is applied to calculate the exergy losses and efficiencies for each stage of the examined processes: resources extraction, materials processing, transport and product manufacturing. Furthermore, exergy values are calculated for the pollutants and wastes
10. Efficacy and tolerability of a new ibuprofen 200mg plaster in patients with acute sports-related traumatic blunt soft tissue injury/contusion.
Science.gov (United States)
Predel, Hans-Georg; Giannetti, Bruno; Connolly, Mark P; Lewis, Fraser; Bhatt, Aomesh
2018-01-01
Ibuprofen is used for the treatment of non-serious pain. This study assessed the efficacy and safety of a new ibuprofen plaster for the treatment of pain associated with acute sports impact injuries/contusions. In this randomised, double-blind, multi-centre, placebo controlled, parallel group study, adults (n = 130; 18-58 years of age) diagnosed with acute sports-related blunt soft tissue injury/contusion were randomized to receive either ibuprofen 200 mg plaster or placebo plaster. Plasters were administered once daily for five consecutive days. The primary assessment was area under the visual analogue scale (VAS) of pain on movement (POM) over 0 to three days (VAS AUC 0-3d ). Other endpoints included algometry AUC from 0 to three days (AUC 0-3d ) and 0 to five days (AUC 0-5d ), to evaluate improvement of sensitivity at the injured site, and patient and investigator global assessment of efficacy. Safety was monitored throughout the study. The ibuprofen plaster resulted in superior reduction in AUC 0-3d compared with placebo; the Least Squares (LS) mean difference was 662.82 mm*h in favour of the ibuprofen 200mg plaster (P = 0.0011). The greater improvement in VAS AUC of POM was also observed after 12 h, 24 h, and five days of therapy. Tenderness also significantly improved with the ibuprofen plaster compared with placebo; LS mean difference in algometry/tenderness AUC 0-3d was 1.87 N/cm 2 *d and AUC 0-5d was 1.87 N/cm 2 *d (P values ≤0.0004). At all study timepoints, a greater percentage of patients and investigators rated the effectiveness of the ibuprofen 200 mg plaster as good/excellent than the placebo plaster. Treatment-emergent adverse events for the ibuprofen plaster were few (≤1.5%) and were mild in severity. The results of this study indicate 200 mg plaster is effective and safe for the treatment of pain due to acute sports-related traumatic blunt soft tissue injury/contusion in adults.
11. Constraining the origin of the Messinian gypsum deposits using coupled measurement of δ^{18}O/δD in gypsum hydration water and salinity of fluid inclusions Science.gov (United States) Evans, Nicholas P.; Gázquez, Fernando; McKenzie, Judith A.; Chapman, Hazel J.; Hodell, David A. 2016-04-01 We used oxygen and hydrogen isotopes of gypsum hydration water (GHW) coupled with salinity deduced from ice melting temperatures of primary fluid inclusions in the same samples (in tandem with 87Sr/86Sr, δ34S and other isotopic measurements) to determine the composition of the mother fluids that formed the gypsum deposits of the Messinian Salinity Crisis from shallow and intermediate-depth basins. Using this method, we constrain the origin of the Messinian Primary Lower Gypsum (PLG) of the Sorbas basin (Betic foreland) and both the Upper Gypsum (UG) and the Lower Gypsum of the Sicilian basin. We then compare these results to measurements made on UG recovered from the deep Ionian and Balearic basins drilled during DSDP Leg 42A. The evolution of GHW δ18O/δD vs. salinity is controlled by mixing processes between fresh and seawater, coupled with the degree of evaporation. Evaporation and subsequent precipitation of gypsum from fluids dominated by freshwater will result in a depressed 87Sr/86Sr values and different trajectory in δ18O/δD vs. salinity space compared to fluids dominated by seawater. The slopes of these regression equations help to define the end-members from which the fluid originated. For example, salinity estimates from PLG cycle 6 in the Sorbas basin range from 18 to 51ppt, and after correction for fractionation factors, estimated δ18O and δD values of the mother water are low (-2.6 meteoric water during gypsum deposition, while 87Sr/86Sr (0.708942 fall below those expected from the evaporation of seawater alone, the slope of the regression equation is similar to that of seawater evaporation. This implies that there is a change up-section from a dominantly marine environment in cycle 2 to a greater influence of meteoric water in cycle 6. The UG from the Sicilian basin display greater δ18O/δD values (2.9 meteoric water that subsequently underwent intense evaporation. This observation concurs with the low values of 87Sr/86Sr from the same UG 12. The influence of the pore structure on the moisture transport in lime plaster-brick systems as studied by NMR Czech Academy of Sciences Publication Activity Database Nunes, Cristiana Lara; Pel, L.; Kunecký, Jiří; Slížková, Zuzana 2017-01-01 Roč. 142, July (2017), s. 395-409 ISSN 0950-0618 R&D Projects: GA MŠk(CZ) LO1219 Keywords : drying * moisture transport * NMR * pore water distribution * plaster * brick * lime * metakaolin * water-repellent * linseed oil Subject RIV: AL - Art, Architecture, Cultural Heritage OBOR OECD: Materials engineering Impact factor: 3.169, year: 2016 http://www.sciencedirect.com/science/article/pii/S0950061817304543 13. Experienced materials in wet limestone-gypsum FGD system Energy Technology Data Exchange (ETDEWEB) Hasegawa, S. [Mitsubishi Heavy Industry, Hiroshima (Japan). Hiroshima Research and Development Center; Iwashita, K.; Ochi, E.; Higuchi, T. [Mitsubishi heavy Industry, Yokohama (Japan) 1998-12-31 This study was made on the corrosion resistivity evaluation method used for material selection in the Wet Limestone-Gypsum FGD system with examples of various process configuration, their corrosion environment, and the materials used in them. The wet limestone-gypsum process FGD plant is broadly divided into two types-ash-separated (dual-loop) process, and ash-mixed (single-loop) process-depending on whether the flue gas is separated from ash before being led into the absorber or led as it is into the absorber mixed with ash. Presently, the single-loop process has become the mainstream process however. The dual -loop process comprises a dedusting tower (quencher) and an absorption tower (absorber). In the quencher ash is removed with sprayed water where most of the HCl, HF etc., and a part of SO{sub x} and NO{sub x} contained in the flue gas are also removed with absorption. On the contrary, in the single-loop process which is configured of only the absorber, the flue gas is introduced into it as it is contained with ash, SO{sub x}, NO{sub x}, HCl, HF etc. The corrosion environment in these plants largely differs depending on the process type and condition. The absorber recirculated liquid has various ion inclusions among which Cl{sup {minus}} promotes pitting corrosion and crevice corrosion while SO{sub 4}{sup 2{minus}} inhibits these corrosions. Both Cl{sup {minus}} and SO{sub 4}{sup 2{minus}} cover an extremely large range between 25 to 100,000 ppm and 564 to 73,600 ppm respectively, and their influence on the corrosion is related to their activity which is decided by Ca{sup 2+}, Mg{sup 2+}, Na{sup +}, NH{sub 4}{sup +}, H{sup +} and liquid temperature. The balance of these ions is decided by the gas composition, limestone composition, make-up water and wastewater mass balance etc., of individual plants. Accordingly, materials of FGD plant are selected on the basis of evaluated results of corrosion resistivity test made under such simulated process conditions of 14. Soil composition and nutritional status of apple as affected by long-term application of gypsum Directory of Open Access Journals (Sweden) Gilberto Nava 2012-02-01 Full Text Available Gypsum does not affect the soil negative charges and maintains sulfate in the soil solution, making it one of the cheapest products to increase Ca activity in soil solution, especially in the deeper soil layers. Higher Ca levels in the soil solution can increase the uptake of this nutrient by apple trees, reducing the risk of physiological disorders caused by Ca deficiency. This study assessed the effect of long-term gypsum application on some soil properties and on the chemical composition of leaves and fruits of an apple cultivar susceptible to fruit disorders associated with low Ca. The experiment was conducted in São Joaquim, in the South of Brazil, from 2001 to 2009. Gypsum rates of 0, 1.0, 2.0 and 3.0 t ha-1 were annually broadcast over the soil surface, without incorporation, in an apple orchard with cultivar ´Catarina´, planted in 1997. Gypsum application over eight consecutive years had no effect on soil exchangeable K and Al to a depth of 80 cm, but increased exchangeable Ca in the sampled layers (0-10, 10-20, 40-60 and 60-80 cm, while exchangeable Mg decreased only in the surface layer (0-20 cm. Gypsum did not affect the concentration of any nutrient in the fruits, including Ca. The same was verified in the leaves, except for Mg which decreased with increased gypsum rate. Despite increasing the availability of Ca in the soil profile to a depth of 80 cm, gypsum was not effective to increase the Ca content in leaves and fruits of an apple cultivar susceptible to Ca deficiency grown in an appropriately limed soil. 15. Surface Coating of Gypsum-Based Molds for Maxillofacial Prosthetic Silicone Elastomeric Material: The Surface Topography. Science.gov (United States) Khalaf, Salah; Ariffin, Zaihan; Husein, Adam; Reza, Fazal 2015-07-01 This study aimed to compare the surface roughness of maxillofacial silicone elastomers fabricated in noncoated and coated gypsum materials. This study was also conducted to characterize the silicone elastomer specimens after surfaces were modified. A gypsum mold was coated with clear acrylic spray. The coated mold was then used to produce modified silicone experimental specimens (n = 35). The surface roughness of the modified silicone elastomers was compared with that of the control specimens, which were prepared by conventional flasking methods (n = 35). An atomic force microscope (AFM) was used for surface roughness measurement of silicone elastomer (unmodified and modified), and a scanning electron microscope (SEM) was used to evaluate the topographic conditions of coated and noncoated gypsum and silicone elastomer specimens (unmodified and modified) groups. After the gypsum molds were characterized, the fabricated silicone elastomers molded on noncoated and coated gypsum materials were evaluated further. Energy-dispersive X-ray spectroscopy (EDX) analysis of gypsum materials (noncoated and coated) and silicone elastomer specimens (unmodified and modified) was performed to evaluate the elemental changes after coating was conducted. Independent t test was used to analyze the differences in the surface roughness of unmodified and modified silicone at a significance level of p SEM analysis results showed evident differences in surface smoothness. EDX data further revealed the presence of the desired chemical components on the surface layer of unmodified and modified silicone elastomers. Silicone elastomers with lower surface roughness of maxillofacial prostheses can be obtained simply by coating a gypsum mold. © 2014 by the American College of Prosthodontists. 16. Urea Hydrolysis and Calcium Carbonate Precipitation in Gypsum-Amended Broiler Litter. Science.gov (United States) Burt, Christopher D; Cabrera, Miguel L; Rothrock, Michael J; Kissel, D E 2018-01-01 Broiler () litter is subject to ammonia (NH) volatilization losses. Previous work has shown that the addition of gypsum to broiler litter can increase nitrogen mineralization and decrease NH losses due to a decrease in pH, but the mechanisms responsible for these effects are not well understood. Therefore, three laboratory studies were conducted to evaluate the effect of gypsum addition to broiler litter on (i) urease activity at three water contents, (ii) calcium carbonate precipitation, and (iii) pH. The addition of gypsum to broiler litter increased ammonium concentrations ( litter pH by 0.43 to 0.49 pH units after 5 d ( litter only increased on Day 0 for broiler litter with low (0.29 g HO g) and high (0.69 g HO g) water contents, and on Day 3 for litter with medium (0.40 g HO g) water content ( litter with gypsum also caused an immediate decrease in litter pH (0.22 pH units) due to the precipitation of calcium carbonate (CaCO) from gypsum-derived calcium and litter bicarbonate. Furthermore, as urea was hydrolyzed, more urea-derived carbon precipitated as CaCO in gypsum-treated litter than in untreated litter ( litter with gypsum favors the precipitation of CaCO, which buffers against increases in litter pH that are known to facilitate NH volatilization. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc. 17. A controlled clinical study on the new topical dosage form of DHEP plasters in patients suffering from localized inflammatory diseases. Science.gov (United States) Rosenthal, M; Bahous, I 1993-01-01 In this clinical study the efficacy and the tolerability of a new topical formulation, DHEP plaster, have been evaluated. The plaster consists of an auto-adhesive medicated gauze pad of standard dimensions (10 x 15 cm) containing 180 mg DHEP. The reference drug was a well-known topical drug, diclofenac diethylammonium (DDA) emulgel at 1.16%. Treatments were applied to the affected area for 14 days: DHEP plaster b.i.d. and DDA emulgel q.i.d. A total of 190 patients, affected by various inflammatory diseases, participated in this clinical study. In both treatment groups (DHEP n = 96 patients, DDA n = 94 patients) a clear improvement in the disease and a rapid reduction in pain were observed. The statistical comparison between the two treatments showed a significant difference in favour of DHEP. However a comparison of the results, according to the different diagnoses, did not reveal any statistical significance. Both treatments were well tolerated, although five (DHEP n = 2, DDA n = 3) out of the 190 patients (2.6%) showed transient side effects (pruritus or erythema, both of light intensity). 18. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder. Science.gov (United States) Zhong, Shiyun; Ni, Kun; Li, Jinmei 2012-07-01 A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO(4)(2-) from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO(4)(2-) releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO(4)(2-) from the mortar with 20% FGD gypsum is 9200 mg·m(-2), which is lower than that from the mortar with 95% cement clinker and 5% FGD gypsum. Copyright © 2012 Elsevier Ltd. All rights reserved. 19. Energy and exergy assessments of a perlite expansion furnace in a plaster plant International Nuclear Information System (INIS) Gürtürk, Mert; Oztop, Hakan F.; Hepbaslı, Arif 2013-01-01 Highlights: • Importance of energy efficiency on perlite process is discussed. • Effects of perlite production on 3E, namely, energy, environment and economics is presented. • The system must be replaced with the developed technology and the return of the investment would be less than 18 months. - Abstract: In this study, energy and exergy assessments of a perlite expansion furnace in a plaster factory are performed. Chemical properties of the perlite and its application areas are described. Energy and exergy relations according to the First and Second Law of Thermodynamics are derived. Energy and exergy efficiencies, losses and exergy destructions are calculated based on the measurements obtained from the system. Evaluations of environmental impact, energy management and economic are finally generalized according to the obtained results. Energy and exergy efficiencies of the furnace are determined to be 66% and 26%, respectively. Reference temperature effects on exergy efficiency, destruction and sustainability index are also presented. The results showed that the furnace has not been well designed in terms of thermal aspects due to high energy and exergy losses and the manufacturer producing the perlite expanded should establish an energy management structure 20. Plaster mortars with polymer fibers and additives investigated by 1H NMR relaxometry Science.gov (United States) Mustea, Andrei; Manea, Daniela L.; Jumate, Elena; Orbán, Yvette A.; Fechete, Radu 2017-12-01 Plaster mortars with polypropylene (pp) fibers and/or additives were investigated by 1H NMR relaxometry. Two recipes are proposed and are based on a commercially available mortar or are self-prepared and have different content of polypropylene fibers, which play the role of reinforcement agent, and/or Sika additive which is a waterproofing agent. The distributions of transverse relaxation times, T2 were obtained at 1, 3, 7 and 28 days after preparation. For the majority of T2-distributions four peaks are observed and, are associated with the hydration water (to the mineralogical components) and water in small, medium and large pores. The evolution in time, from 1 to 28 days, of the T2-distributions indicates the effects of pp fibers and Sika additive in the formation of pore microstructure. The degree of homogeneity of prepared receipts was evaluated from the relative peak-width and compared with mechanical measurements. Finally, we shown that the inverse of the transverse relaxation time values, T2-1, characteristic to the hydration water depends linearly on the resistance at compression measured for the 1÷28 days period, proving the important role of hydrations to the mechanical properties of the final product. 1. Trichobezoar, Rapunzel Syndrome, Tricho-Plaster Bezoar – A Report of Three Cases International Nuclear Information System (INIS) Czerwińska, Katarzyna; Bekiesińska-Figatowska, Monika; Brzewski, Michał; Gogolewski, Michał; Wolski, Marek 2015-01-01 Trichobezoar is an uncommon entity observed mostly in young women. Symptoms in presenting patients are usually due to the large mass of the bezoar or malabsorption of nutrients. Trichobezoar is almost always associated with trichotillomania and trichophagia. Three teenage girls, aged 13, 15, and 16, were diagnosed due to palpable epigastric masses. Additionally the oldest patient presented with symptoms of ileus while the other two patients had weight loss and anaemia. Besides the 15-year-old patient complained of paroxysmal abdominal pains. Patients were subjected to plain radiographic examinations of abdomen which revealed large epigastric tumours, with additional calcifications observed in the youngest girl. Subsequent gastroscopy (the 15-year-old patient) or ultrasonographic examination and computed tomography scans (13- and 16-year-old patients) allowed to establish the diagnosis of giant bezoars: trichobezoars in two older patients and tricho-plaster bezoar in the youngest one. All the tumours were surgically resected and psychiatric treatment was undertaken. 1. Trichobezoar should be taken into consideration in differential diagnosis of epigastric tumours in children, especially teenage girls. 2. The conventional ultrasonographic and radiographic examinations of the abdomen are insufficient for determination of the nature of the mass. A thorough medical history interview and clinical examination may give directions regarding the further diagnosis.3. Trichotillomania and trichophagia are obsessive-compulsive disorders, and therefore patients with trichobezoars should be under psychiatric care to prevent recurrence of the disease 2. Gypsum dissolution risk analysis in the Prealpine part of the Vaud County (Western Switzerland) Science.gov (United States) Nicolet, Pierrick; Choffet, Marc; Bohren, Delphine; Derron, Marc-Henri; Jaboyedoff, Michel; Lauraux, Bertrand; Lance, Jean-Marc; Champod, Eric 2013-04-01 Subsidence or collapse due to bedrock dissolution is a relatively common phenomenon in Vaud County (Western Switzerland). Indeed, soluble rocks are present in the Jura and Prealpine parts. Solubility is significantly higher in evaporitic rocks (such as gypsum) than in Limestones, resulting in possibly important dissolution during a building's lifetime. In Limestone, subsidence results mainly from cover collapse over existing voids. This study aims at evaluating the cost of this phenomenon for the building portfolio of the region in which gypsum occurs. Currently, 2.5% of the portfolio value is located over gypsum-bearing formations and is therefore potentially affected. Since this phenomenon is not covered by the public building insurance yet, no centralized event record exists. Therefore, a survey has been conducted with the affected communities to estimate the events frequency and damage severity. Some records from the archives of BERTAND LAURAUX SA have been added and allow to compare reparation costs with insured values. From these cases, a frequency and a buildings vulnerability distribution are established. The vulnerability distribution is considered to represent the reality, whereas the frequency is corrected to take into account the different amount of information gathered in the different municipalities and the incompleteness of the inventory, even in the communities with more information. Assuming that the distribution of collapse events occurs with a constant average frequency and is time-independent, insurance financial years are modeled with a number of cases assigned randomly following a Poisson distribution. A Monte Carlo simulation is performed, where the affected buildings value is chosen among the potentially affected portfolio and its corresponding damage rate is assigned following the distribution previously established. The maximum damage for each building is limited to CHF 1,000,000 (EUR 827,000), to ignore unrealistic values. Thus, a cost 3. Messinian Salinity Crisis' Primary Evaporites: the shallow gypsum vs. deep dolomite formation paradox solved Science.gov (United States) De Lange, G. J.; Krijgsman, W. 2015-12-01 The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, resulting in deposition of 1-3 km thick evaporites at the Mediterranean seafloor. A considerable, long-lasting controversy existed on the modes of their formation, including the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions at a precessional rhythm. Gypsum precipitation only occurred at marginal- and dolomite formation at deeper settings. A range of potential explanations was given, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are commonly neglected but may explain that different deposits formed in shallow vs deep environments without exceptional physical boundary conditions for each. A unifying mechanism is presented in which gypsum formation occurs at all shallow water depths but its preservation is limited to shallow sedimentary settings. In contrast, ongoing deep-basin anoxic organic matter (OM) degradation processes result in dolomite formation. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always oversaturated relative to dolomite but its formation is inhibited by the presence of dissolved sulphate. Thus conditions for formation of gypsum exclude those for formation of dolomite and vice versa. Another process linking the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, ongoing OM-degradation may result in reducing the sulphate and enhancing the dissolved carbonate content. Such low-sulphate / high carbonate conditions in MSC deepwater are. unfavorable for gypsum preservation and favorable for dolomite formation, and always coincide with anoxic, i.e. oxygen-free conditions. Including dynamic biogeochemical processes in the thusfar static 4. Effects of gypsum and bulk density on neutron probe calibration curves International Nuclear Information System (INIS) Arslan, Awadis; Razzouk, A.K. 1993-10-01 The effects of gypsum and bulk density on the neutron probe calibration curve were studied in the laboratory and in the field. The effect of bulk density was negligible for the soil studied in the laboratory, while it was significant for the field calibration. An increase in the slope of moisture content on a volume basis vs. count ratio with increasing gypsum content at the soil was observed in the laboratory calibration. A simple method for correction of the calibration curve for gypsum content was adopted to obtain a specific curve for each layer. The adapted method requires the gypsum fraction to be estimated for each layer and then incorporated in the calibration curve to improve the coefficient of determination. A field calibration showed an improvement of the determination coefficient by introducing bulk density and gypsum fraction, in addition to count ratio using moisture content on a volume basis as a dependent variable in multi linear regression analysis. The same procedure was successful with variable gravel fractions. (author). 18 refs., 3 figs., 2 tabs 5. Effect of alginate chemical disinfection on bacterial count over gypsum cast. Science.gov (United States) Haralur, Satheesh B; Al-Dowah, Omir S; Gana, Naif S; Al-Hytham, Abdullah 2012-05-01 To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 213). Gypsum cast (type III) were made from all the impression. Impressions and gypsum cast were swabbed in mid palatal region for bacterial culture. Bacterial colony counting done after 3 days of incubation at 37℃ in blood agar media. The data obtained was analyzed by one way ANOVA test at a significant difference level of 0.05. Group I and Group II showed significantly more bacteria compared to Group III and Group IV. Bacterial colonies on the alginate impression and gypsum cast in group disinfected with Sodium hypochlorite (1 : 10) were 0.18, 0.82 respectively compared to group treated with iodophor (1 : 213). There was an increase in bacterial count on dental cast compared to source alginate impressions. Sodium hypochlorite (1 : 10) was found to be better disinfectant for alginate impression. There was an indication of increase in number of bacteria from alginate impression to making of dental cast. Additional gypsum cast disinfectant procedures need to be encouraged to completely eliminate cross infection to dental laboratory. 6. Gypsum-permineralized microfossils and their relevance to the search for life on Mars. Science.gov (United States) Schopf, J William; Farmer, Jack D; Foster, Ian S; Kudryavtsev, Anatoliy B; Gallardo, Victor A; Espinoza, Carola 2012-07-01 Orbital and in situ analyses establish that aerially extensive deposits of evaporitic sulfates, including gypsum, are present on the surface of Mars. Although comparable gypsiferous sediments on Earth have been largely ignored by paleontologists, we here report the finding of diverse fossil microscopic organisms permineralized in bottom-nucleated gypsums of seven deposits: two from the Permian (∼260 Ma) of New Mexico, USA; one from the Miocene (∼6 Ma) of Italy; and four from Recent lacustrine and saltern deposits of Australia, Mexico, and Peru. In addition to presenting the first report of the widespread occurrence of microscopic fossils in bottom-nucleated primary gypsum, we show the striking morphological similarity of the majority of the benthic filamentous fossils of these units to the microorganisms of a modern sulfuretum biocoenose. Based on such similarity, in morphology as well as habitat, these findings suggest that anaerobic sulfur-metabolizing microbial assemblages have changed relatively little over hundreds of millions of years. Their discovery as fossilized components of the seven gypsiferous units reported suggests that primary bottom-nucleated gypsum represents a promising target in the search for evidence of past life on Mars. Key Words: Confocal laser scanning microscopy-Gypsum fossils-Mars sample return missions-Raman spectroscopy-Sample Analysis at Mars (SAM) instrument-Sulfuretum. 7. A DOC coagulant, gypsum treatment can simultaneously reduce As, Cd and Pb uptake by medicinal plants grown in contaminated soil. Science.gov (United States) Kim, Hyuck Soo; Seo, Byoung-Hwan; Kuppusamy, Saranya; Lee, Yong Bok; Lee, Jae-Hwang; Yang, Jae-E; Owens, Gary; Kim, Kwon-Rae 2018-02-01 The efficiency of gypsum, as a dissolved organic carbon (DOC) coagulator, for the simultaneous immobilization of two heavy metals (Cd and Pb) and one metalloid (As) in agricultural soils near an abandoned mining site was examined. The agricultural soil was defined as long-term contaminated as As (1540mgkg -1 ), Cd (55mgkg -1 ) and Pb (1283mgkg -1 ) concentrations exceeded the Korean guideline values for As (25mgkg -1 ), Cd (4mgkg -1 ), and Pb (200mgkg -1 ). Gypsum was incorporated into the contaminated soil at 3% (w/w). In comparison two commonly using immobilizing agents (lime and compost), together with a mixture (lime+gypsum) were also included in the pot trial for the cultivation of two medical plants (A. gigas and A. macrocephala) and to evaluate the effectiveness of gypsum on As, Cd and Pb immobilization. The results showed that even though pH change-induced immobilizing agents such as lime were more effective than gypsum at immobilizing Cd and Pb, addition of gypsum also effectively reduced heavy metal phytoavailability as indicated by decreases in the concentration of Cd and Pb in medicinal plants. Furthermore, gypsum and gypsum+ lime were also most effective in reducing As concentrations in both plants studied. This was mainly attributed to significant decreases in soil DOC (48-64%) when gypsum and gypsum+lime were applied to the soil. Consequently, it was concluded that enhanced DOC coagulation with gypsum, could be considered as a promising technique for the immobilization of both metals (Cd and Pb) and metalloids (As) in agricultural soils. Copyright © 2017 Elsevier Inc. All rights reserved. 8. Effect of EDTA and gypsum on self diffusion coefficient of zinc in alkali soil International Nuclear Information System (INIS) Gupta, G.N.; Deb, D.L. 1981-01-01 The effect of EDTA and gypsum application on the rate of zinc diffusion was studied in an alkali soil. Gypsum application at the rate of half gypsum requirement (GR) increased the apparent self diffusion coefficient of zinc (DaZn) and decreased the capacity factor (B) of soil. The higher rates (full GR and double GR) depressed the rate of zinc diffusion and increased the B value. Application of EDTA at the rate of 0.77 μeg -1 of soil produced 1600 and 24 fold increase in DaZn and DpZn values respectively and 100 times drop in B value. Addition of 55 ppm Zn to the soil significantly increased the DaZn and DpZn values. (author) 9. Dimensional accuracy and surface property of titanium casting using gypsum-bonded alumina investment. Science.gov (United States) Yan, Min; Takahashi, Hidekazu; Nishimura, Fumio 2004-12-01 The aim of the present study was to evaluate the dimensional accuracy and surface property of titanium casting obtained using a gypsum-bonded alumina investment. The experimental gypsum-bonded alumina investment with 20 mass% gypsum content mixed with 2 mass% potassium sulfate was used for five cp titanium castings and three Cu-Zn alloy castings. The accuracy, surface roughness (Ra), and reaction layer thickness of these castings were investigated. The accuracy of the castings obtained from the experimental investment ranged from -0.04 to 0.23%, while surface roughness (Ra) ranged from 7.6 to 10.3microm. A reaction layer of about 150 microm thickness under the titanium casting surface was observed. These results suggested that the titanium casting obtained using the experimental investment was acceptable. Although the reaction layer was thin, surface roughness should be improved. 10. STRUCTURE AND PROPERTIES OF COMPOSITE MATERIAL BASED ON GYPSUM BINDER AND CARBON NANOTUBES Directory of Open Access Journals (Sweden) CHUMAK Anastasia Gennadievna 2013-04-01 Full Text Available The aim of this work is to carry out a number of studies in the area of nanomodification of gypsum binder matrix and to investigate the influence of multilayer carbon nanotubes on the structure, physical and mechanical properties of obtained composites. The study of the gypsum binders structure formation mechanisms with the use of nanoadditives makes it possible to control the production processes of gypsum materials and articles with the given set of properties. The main tasks of the binder nanomodification are: even distribution of carbon nanostructures over the whole volume of material and provision of stability for the nanodimensional modifier during production process of the construction composite. 11. Application of gypsum as shielding against low-energy X-radiation in the radiodiagnosis area International Nuclear Information System (INIS) Lins, J.A.G.; Lima, F.R.A.; Santos, M.A.P. dos; Oliveira, D.N.S. de; Silva, V.H.F.F. da 2017-01-01 In recent years, materials such as lead, concrete and iron have been studied for use as shielding for ionizing radiations of different energies in radiative installations. In the radiodiagnosis area, lead and barite are the most used materials as shielding. However, for beams of low energy X-radiation, such as in mammography and dentistry, the gypsum material may be used. This study aims to verify the feasibility of the use of gypsum as shielding for low-energy X-ray using standardized dental X-ray beams in a metrology laboratory. The project will allow a better understanding in the study of gypsum used as shielding, certifying its use as a good attenuator for low-energy X-ray 12. Analysis of cubic and orthorhombic C3A hydration in presence of gypsum and lime KAUST Repository Kirchheim, A. P. 2009-02-26 Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to study the microstructural changes and phase development that take place during the hydration of cubic (pure) and orthorhombic (Na-doped) tricalcium aluminate (C3A) and gypsum in the absence and presence of lime. The results demonstrate that important differences occur in the hydration of each C3A polymorph and gypsum when no lime is added; orthorhombic C3A reacts faster with gypsum than the cubic phase, forming longer ettringite needles; however, the presence of lime slows down the formation of ettringite in the orthorhombic sample. Additional rheometric tests showed the possible effects on the setting time in these cementitious mixes. 13. Analysis of cubic and orthorhombic C3A hydration in presence of gypsum and lime KAUST Repository Kirchheim, A. P.; Fernà ndez-Altable, V.; Monteiro, P. J. M.; Dal Molin, D. C. C.; Casanova, I. 2009-01-01 Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to study the microstructural changes and phase development that take place during the hydration of cubic (pure) and orthorhombic (Na-doped) tricalcium aluminate (C3A) and gypsum in the absence and presence of lime. The results demonstrate that important differences occur in the hydration of each C3A polymorph and gypsum when no lime is added; orthorhombic C3A reacts faster with gypsum than the cubic phase, forming longer ettringite needles; however, the presence of lime slows down the formation of ettringite in the orthorhombic sample. Additional rheometric tests showed the possible effects on the setting time in these cementitious mixes. 14. Petroleum Sludge as gypsum replacement in cement plants: Its Impact on Cement Strength Science.gov (United States) Benlamoudi, Ali; Kadir, Aeslina Abdul; Khodja, Mohamed 2017-08-01 Due to high cost of cement manufacturing and the huge amount of resources exhaustion, companies are trying to incorporate alternative raw materials or by-products into cement production so as to produce alternative sustainable cement. Petroleum sludge is a dangerous waste that poses serious imparts on soil and groundwater. Given that this sludge contains a high percentage of anhydrite (CaSO4), which is the main component of gypsum (CaSO4.2H2O), it may play the same gypsum role in strength development. In this research, a total replacement of gypsum (100%) has been substituted by petroleum sludge in cement production and has led to an increase of 28.8% in UCS values after 28 curing days. Nevertheless, the burning of this waste has emitted a considerable amount of carbon monoxide (CO) gas that needs to be carefully considered prior to use petroleum sludge within cement plants. 15. The effect of magnesium on partial sulphate removal from mine water as gypsum. Science.gov (United States) Tolonen, Emma-Tuulia; Rämö, Jaakko; Lassi, Ulla 2015-08-15 The aim of this research was to investigate the effect of magnesium on the removal efficiency of sulphate as gypsum from mine water. The precipitation conditions were simulated with MINEQL + software and the simulation results were compared with the results from laboratory jar test experiments. Both the simulation and the laboratory results showed that magnesium in the mine water was maintaining sulphate in a soluble form as magnesium sulphate (MgSO4) at pH 9.6. Thus magnesium was preventing the removal of sulphate as gypsum (CaSO4·2H2O). However, change in the lime precipitation pH from 9.6 to 12.5 resulted in magnesium hydroxide (Mg(OH)2) precipitation and improved sulphate removal. Additionally, magnesium hydroxide could act as seed crystals for gypsum precipitation or co-precipitate sulphate further enhancing the removal of sulphate from mine water. Copyright © 2015 Elsevier Ltd. All rights reserved. 16. Achievement report for fiscal 2000 on development of technology to recycle disintegrated waste gypsum boards; 1999 nendo kaitai haisekko board no saishigenka gijutsu kaihatsu seika hokokusho Energy Technology Data Exchange (ETDEWEB) NONE 2001-03-01 Investigations and researches have been made on disintegrated waste gypsum boards generated in building demolishing sites, with a target of recycling them as a raw material for boards. In the investigations, the actual status of discarding the disintegrated gypsum boards was identified, whereas the harmful substance contents such as of heavy metals were verified to be below the environmental criteria. As a method to remove impurities and foreign materials from the disintegrated waste gypsum boards, the hydration crushing method was established, in which volumetric change when hemihydrate gypsum returns to gypsum dehydrate is utilized, and bond of gypsum particles with each other and with impurities is destructed to separate them into simple substances. Furthermore, discussions were given on the reforming conditions to reform in an energy saving manner the disintegrated waste gypsum boards into high-quality large-size hemihydrate gypsum by using the wet-type process that utilizes the reversible reaction between hemihydrate gypsum and gypsum dehydrate in the disintegrated waste gypsum boards. A manufacturing process to put the recycled gypsum into practical use was also discussed. Prototype board fabrication and tests were performed by using the reformed gypsum board materials, wherein good results were obtained from all of the practical, chemical, and physical tests. (NEDO) 17. Plasma pharmacokinetics and synovial concentrations of S-flurbiprofen plaster in humans. Science.gov (United States) Yataba, Ikuko; Otsuka, Noboru; Matsushita, Isao; Kamezawa, Miho; Yamada, Ichimaro; Sasaki, Sigeru; Uebaba, Kazuo; Matsumoto, Hideo; Hoshino, Yuichi 2016-01-01 The purpose of this study is to investigate the pharmacokinetics and deep tissue penetration capability of the newly developed S-flurbiprofen plaster (SFPP) in humans. Study 1: SFPP tape-type patch (2-60 mg) was applied to the lower back for 24 h in healthy adult volunteers. S-flurbiprofen (SFP) plasma concentration was measured over time to examine SFP pharmacokinetics. Study 2: SFPP (20 mg) was applied for 12 h to the affected knee of osteoarthritis (OA) patients who were scheduled for total knee arthroplasty. Deep tissues (synovial tissue and synovial fluid) were collected during surgery to compare SFP concentrations after application of SFPP or a commercially available flurbiprofen (FP) gel-type patch. Study 1: The plasma concentration of SFP was sustained during 24-h topical application of the SFPP, showing a high percutaneous absorption ratio of 51.4-72.2 %. Cmax and AUC0-∞ were dose-proportional. Study 2: After application of the SFPP for 12 h, SFP concentrations in the synovial tissue and synovial fluid were 14.8-fold (p = 0.002) and 32.7-fold (p < 0.001) higher, respectively, than those achieved by the FP patch. Sustained plasma concentration of SFP and high percutaneous absorption ratio was observed after 24-h topical application of the SFPP. Compared to the FP patch, the SFPP showed superior percutaneous absorption and greater tissue penetration of SFP into the synovial tissue. Greater tissue penetration of the SFPP seemed to be primarily due to its formulation. Thus, SFPP is expected to show higher efficacy for the treatment of knee OA. 18. Multi-technique investigation of Roman decorated plasters from Villa dei Quintili (Rome, Italy) International Nuclear Information System (INIS) Crupi, Vincenza; Galli, Giuliana; La Russa, Mauro Francesco; Longo, Francesca; Maisano, Giacomo; Majolino, Domenico; Malagodi, Marco; Pezzino, Antonino; Ricca, Michela; Rossi, Barbara; Ruffolo, Silvestro Antonio 2015-01-01 Highlights: • A multi-technique non-invasive approach using portable instrumentation is proposed. • Due to the use of different techniques, pigments of same color were distinguished. • The experimental results shed light on the used painting methodologies. • The experimental results provided useful information for restoration processes. • This work is the first study of coloring matter used in Villa dei Quintili. - Abstract: In the present study, we investigated by the joint use of portable instrumentations, namely a handheld X-ray fluorescence (XRF) analyser and a portable Raman spectrometer, the painted surface of plasters withdrawn from different areas of an important Roman monumental complex, known as Villa dei Quintili (Rome, Italy), dated back to the first half of the 2nd century a.C. XRF and Raman measurements contributed to the identification of the pigments through the elemental and molecular composition, respectively. In particular, the multi-technique non-invasive approach proved to be crucial for distinguishing two different reddish pigments. In order to confirm and integrate XRF and Raman results, two micro-destructive laboratory methods, namely optical microscopy (OM) and scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS), were also employed on the same samples. All the experimental results shed light on the material characterizing the painted surface layer and the painting methodologies, providing in principle useful information for proper restoration processes. It is worth underlining that this experimental investigation takes part of a recent multidisciplinary study performed on this impressive archaeological site, aimed to characterize for the first time the monumental complex from an archaeometric point of view 19. Multi-technique investigation of Roman decorated plasters from Villa dei Quintili (Rome, Italy) Energy Technology Data Exchange (ETDEWEB) Crupi, Vincenza, E-mail: [email protected] [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina (Italy); Galli, Giuliana [Soprintendenza Speciale per i Beni Archeologici di Roma, Villa dei Quintili, via Appia Nuova 1092, 00197 Roma (Italy); La Russa, Mauro Francesco [Dipartimento di Biologia, Ecologia e Scienze della Terra (DiBEST), Università degli Studi della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende (Cs) (Italy); Longo, Francesca; Maisano, Giacomo; Majolino, Domenico [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina (Italy); Malagodi, Marco [Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia (Italy); Pezzino, Antonino [Dipartimento di Scienze Biologiche, Geologiche e Ambientali—Sezione di Scienze della Terra, Università degli Studi di Catania, Corso Italia 57, 95129 Catania (Italy); Ricca, Michela [Dipartimento di Biologia, Ecologia e Scienze della Terra (DiBEST), Università degli Studi della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende (Cs) (Italy); Rossi, Barbara [Elettra – Sincrotrone Trieste, Strada Statale 14 km 163.5, Area Science 70 Park, 34149 Trieste (Italy); Dipartimento di Fisica, Università degli Studi di Trento, via Sommarive 14, 38123 Povo, Trento (Italy); Ruffolo, Silvestro Antonio [Dipartimento di Biologia, Ecologia e Scienze della Terra (DiBEST), Università degli Studi della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende (Cs) (Italy); and others 2015-09-15 Highlights: • A multi-technique non-invasive approach using portable instrumentation is proposed. • Due to the use of different techniques, pigments of same color were distinguished. • The experimental results shed light on the used painting methodologies. • The experimental results provided useful information for restoration processes. • This work is the first study of coloring matter used in Villa dei Quintili. - Abstract: In the present study, we investigated by the joint use of portable instrumentations, namely a handheld X-ray fluorescence (XRF) analyser and a portable Raman spectrometer, the painted surface of plasters withdrawn from different areas of an important Roman monumental complex, known as Villa dei Quintili (Rome, Italy), dated back to the first half of the 2nd century a.C. XRF and Raman measurements contributed to the identification of the pigments through the elemental and molecular composition, respectively. In particular, the multi-technique non-invasive approach proved to be crucial for distinguishing two different reddish pigments. In order to confirm and integrate XRF and Raman results, two micro-destructive laboratory methods, namely optical microscopy (OM) and scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS), were also employed on the same samples. All the experimental results shed light on the material characterizing the painted surface layer and the painting methodologies, providing in principle useful information for proper restoration processes. It is worth underlining that this experimental investigation takes part of a recent multidisciplinary study performed on this impressive archaeological site, aimed to characterize for the first time the monumental complex from an archaeometric point of view. 20. Testing CO2 Sequestration in an Alkaline Soil Treated with Flue Gas Desulfurization Gypsum (FGDG) Science.gov (United States) Han, Y.; Tokunaga, T. K. 2012-12-01 Identifying effective and economical methods for increasing carbon storage in soils is of interest for reducing soil CO2 fluxes to the atmosphere in order to partially offset anthropogenic CO2 contributions to climate change This study investigates an alternative strategy for increasing carbon retention in soils by accelerating calcite (CaCO3) precipitation and promoting soil organic carbon (SOC) complexation on mineral surfaces. The addition of calcium ion to soils with pH > 8, often found in arid and semi-arid regions, may accelerate the slow process of calcite precipitation. Increased ionic strength from addition of a soluble Ca source also suppresses microbial activity which oxidizes SOC to gaseous CO2. Through obtaining C mass balances in soil profiles, this study is quantifying the efficiency of gypsum amendments for mitigating C losses to the atmosphere. The objective of this study is to identify conditions in which inorganic and organic C sequestration is practical in semi-arid and arid soils by gypsum treatment. As an inexpensive calcium source, we proposed to use flue gas desulfurization gypsum (FGDG), a byproduct of fossil fuel burning electric power plants. To test the hypothesis, laboratory column experiments have been conducted in calcite-buffered soil with addition of gypsum and FGDG. The results of several months of column monitoring are demonstrating that gypsum-treated soil have lowered amounts of soil organic carbon loss and increased inorganic carbon (calcite) production. The excess generation of FGDG relative to industrial and agricultural needs, FGDG, is currently regarded as waste. Thus application of FGDG application in some soils may be an effective and economical means for fixing CO2 in soil organic and inorganic carbon forms.Soil carbon cycle, with proposed increased C retention by calcite precipitation and by SOC binding onto soil mineral surfaces, with both processes driven by calcium released from gypsum dissolution. 1. The solidification of low level radioactive organic fluids with Envirostone Gypsum Cement International Nuclear Information System (INIS) Rosenstiel, T.L.; Lange, R.G. 1984-01-01 The primary method for the management of low level radioactive waste (LLW) has been and continues to be the isolation of the waste in a solid mass. Of the four typical LLW streams, organic fluids pose the most significant waste isolation problem. The organic fluids comprised of lubrication oils, hydraulic fluids, sludges, scintillation fluids, etc., result from the operation and maintenance of nuclear power generating stations, research activities, tooling operations, and diagnostic analyses. The United States Gypsum Company developed the patented Envirostone Gypsum Cement system for the solidification of all types of low level radioactive wastes to facilitate handling and transportation to regulated LLW disposal sites. For the solidification of organic fluids, Envirostone Gypsum Cement is used in conjunction with Envirostone Emulsifier, selected for its ability to emulsify a broad range of organic fluids in aqueous solutions. In the solidification process it is theorized that as the crystalline matrix of the gypsum forms, the micelles of the emulsifier behave as a chemical bridge which draws the organic fluid into the crystalline structure via the hydration water. Initial testing of physical properties of solidified waste forms, including leachability, per the requirements and the procedures specified for 10 CFR Part 61 as outlined in the Branch Technical Position Report from the United States Nuclear Regulatory Commission were in progress as of the writing of this paper. Upon completion of this testing a Topical Report will be submitted to the USNRC for review and approval. The presentation reviews field experience in the use of Envirostone Gypsum Cement for the solidification of low level radioactive organic fluids from nuclear power generating stations and makes an economic comparison between Envirostone Gypsum Cement and portland cement systems 2. Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator Science.gov (United States) Bell, Mary S.; Zolensky, Michael E. 2011-01-01 The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8 3. Gypsum addition to soils contaminated by red mud: implications for aluminium, arsenic, molybdenum and vanadium solubility. Science.gov (United States) Lehoux, Alizée P; Lockwood, Cindy L; Mayes, William M; Stewart, Douglas I; Mortimer, Robert J G; Gruiz, Katalin; Burke, Ian T 2013-10-01 Red mud is highly alkaline (pH 13), saline and can contain elevated concentrations of several potentially toxic elements (e.g. Al, As, Mo and V). Release of up to 1 million m(3) of bauxite residue (red mud) suspension from the Ajka repository, western Hungary, caused large-scale contamination of downstream rivers and floodplains. There is now concern about the potential leaching of toxic metal(loid)s from the red mud as some have enhanced solubility at high pH. This study investigated the impact of red mud addition to three different Hungarian soils with respect to trace element solubility and soil geochemistry. The effectiveness of gypsum amendment for the rehabilitation of red mud-contaminated soils was also examined. Red mud addition to soils caused a pH increase, proportional to red mud addition, of up to 4 pH units (e.g. pH 7 → 11). Increasing red mud addition also led to significant increases in salinity, dissolved organic carbon and aqueous trace element concentrations. However, the response was highly soil specific and one of the soils tested buffered pH to around pH 8.5 even with the highest red mud loading tested (33 % w/w); experiments using this soil also had much lower aqueous Al, As and V concentrations. Gypsum addition to soil/red mud mixtures, even at relatively low concentrations (1 % w/w), was sufficient to buffer experimental pH to 7.5-8.5. This effect was attributed to the reaction of Ca(2+) supplied by the gypsum with OH(-) and carbonate from the red mud to precipitate calcite. The lowered pH enhanced trace element sorption and largely inhibited the release of Al, As and V. Mo concentrations, however, were largely unaffected by gypsum induced pH buffering due to the greater solubility of Mo (as molybdate) at circumneutral pH. Gypsum addition also leads to significantly higher porewater salinities, and column experiments demonstrated that this increase in total dissolved solids persisted even after 25 pore volume replacements. Gypsum 4. Process for fabrication of dry flue gas gypsum. Verfahren zur Herstellung von trockenem Rauchgasgips Energy Technology Data Exchange (ETDEWEB) Wirsching, F.; Hueller, R.; Limmer, B. 1984-06-20 According to the invention gypsum from flue gas wet desulfurization is dried without loss of crystallization water by a 1-4% sidestream of the flue gas in a suspended bed dryer and is subsequently separated in a cyclone. The sidestream is removed after the electrostatic precipitator, where the gas temperature is 100-130 degrees, and returned to the main gas stream prior to desulfurization, thus preventing the dehydration of the gypsum and eliminating the energy costs of reheating the gas stream to prevent acid condensation. 5. GEs worldwide experience with IFO based gypsum producing flue gas desulfurization systems Energy Technology Data Exchange (ETDEWEB) Saleem, A. [GE Environmental Systems, Lebanon, PA (United States) 1994-12-31 The In-Situ Forced Oxidation (IFO) process to produce gypsum in a commercial scale flue gas desulfurization (FGD) system was first demonstrated by GE Environmental Systems in 1980 at the Monticello Generating Station of Texas Utilities. Since then, the IFO technology developed and demonstrated by GE has become the industry standard and is used extensively on a world-wide basis to produce both commercial and disposable-grade gypsum. The paper gives an overview of the development, demonstration, commercial design and current status of the IFO technology. 6. Evaluation of Synthetic Gypsum Recovered via Wet Flue-Gas Desulfurization from Electric Power Plants for Use in Foundries Directory of Open Access Journals (Sweden) R. Biernacki 2012-09-01 Full Text Available This article investigates possible use of waste gypsum (synthetic, recovered via flue-gas desulfurization from coal-fired electric powerplants, in foundries. Energy sector, which in Eastern Europe is mostly composed from coal-fired electric power plants, is one of the largestproducers of sulfur dioxide (SO2.In order to protect the environment and reduce the amount of pollution flue-gas desulfurization (FGD is used to remove SO2 fromexhaust flue gases of fossil-fuel power plants. As a result of this process gypsum waste is produced that can be used in practicalapplications.Strength and permeability tests have been made and also in-depth analysis of energy consumption of production process to investigateways of preparing the synthetic gypsum for casting moulds application. This paper also assesses the chemical composition, strength andpermeability of moulds made with synthetic gypsum, in comparison with moulds made with traditional GoldStar XL gypsum and withceramic molds. Moreover examination of structure of synthetic gypsum, the investigations on derivatograph and calculations of energyconsumption during production process of synthetic gypsum in wet flue-gas desulfurization were made.After analysis of gathered data it’s possible to conclude that synthetic gypsum can be used as a material for casting mould. There is nosignificant decrease in key properties, and on the other hand there is many additional benefits including low energy consumption,decreased cost, and decreased environmental impact. 7. Gypsum and organic matter distribution in a mixed construction and demolition waste sorting process and their possible removal from outputs. Science.gov (United States) Montero, A; Tojo, Y; Matsuo, T; Matsuto, T; Yamada, M; Asakura, H; Ono, Y 2010-03-15 With insufficient source separation, construction and demolition (C&D) waste becomes a mixed material that is difficult to recycle. Treatment of mixed C&D waste generates residue that contains gypsum and organic matter and poses a risk of H(2)S formation in landfills. Therefore, removing gypsum and organic matter from the residue is vital. This study investigated the distribution of gypsum and organic matter in a sorting process. Heavy liquid separation was used to determine the density ranges in which gypsum and organic matter were most concentrated. The fine residue that was separated before shredding accounted for 27.9% of the waste mass and contained the greatest quantity of gypsum; therefore, most of the gypsum (52.4%) was distributed in this fraction. When this fine fraction was subjected to heavy liquid separation, 93% of the gypsum was concentrated in the density range of 1.59-2.28, which contained 24% of the total waste mass. Therefore, removing this density range after segregating fine particles should reduce the amount of gypsum sent to landfills. Organic matter tends to float as density increases; nevertheless, separation at 1.0 density could be more efficient. (c) 2009 Elsevier B.V. All rights reserved. 8. Measurement method for the angulation and tipping of dental crowns using plaster models OpenAIRE Zanelato, Adriano C. Trevisi; Maltagliati, Liliana Ávila; Scanavini, Marco Antônio; Mandetta, Savério 2006-01-01 Este presente estudo teve por finalidade apresentar o desenvolvimento de um dispositivo especialmente projetado para mensurar as angulações e inclinações das coroas dentárias. Tal dispositivo foi utilizado em uma amostra de 60 indivíduos, na faixa etária de 12 a 21 anos, de ambos os gêneros. Os indivíduos apresentavam oclusão normal e nunca haviam sido submetidos a qualquer tipo de intervenção ortodôntica. Sendo assim, a partir desta amostra, estabeleceram-se os valores médios das angulações ... 9. Assessment of groundwater contamination by gypsum dissolution in San Luis Potosí (México) using geoelectrical characterization Science.gov (United States) Arango-Galvan, C.; Ramos-Leal, J. A.; Yáñez-Rodríguez, M. A.; Corbo-Camargo, F. 2017-12-01 The Cerritos and Río Verde aquifers in San Luis Potosí (central México) make up a very complex aquifer system that is seriously affected by the overexploitation and the high concentration of sulphates. Currently, it is partially closed for extraction causing a substantial decrease in per capita drinking water availability affecting to more than 50,000 inhabitants in the region. Therefore, a very comprehensive study has been proposed in order to evaluate not only the groundwater contamination distribution but also to better know the aquifer configuration and its main hydrogeological characteristics as well. These studies include a detailed geological reconnaissance, hydrogeochemical analyses and a geoelectrical characterization. The main goal is to assess the aquifer geometry and to identify the gypsum horizons causing the presence of higher concentrations of sulphates in drinking water. A total of 26 audiomagnetotelluric soundings were measured and modelled along profiles following a perpendicular direction to the NW regional trending. Two-dimensional resistivity models suggest the presence of a shallow conductive layer (C1) with resistivity values ranging from 10 to 20 Ohm.m. It is related to the upper aquifer with a very low exploitation potential. A less conductive horizon (C2; 50 Ohm.m) underlying the shallow aquifer could be related to a very fractured limestone horizon forming a confined aquifer in the middle of the valley. A very resistive layer (R1) is observed underlying C1 and C2 units. This strata shows higher resistivity values (>100 Ohm.m) and could be associated with a reefal limestone identified as El Abra Formation. Finally, a conductive layer (<100 Ohm.m) observed beneath this horizon could be related to the oldest stratigraphic unit outcropping on the region, the Guaxcamá Formation, a gypsum-enriched unit, that contributes to the presence of sulphates in the upper aquifers by dissolution processes. 10. Investigation of Parameters Affecting Gypsum Dewatering Properties in a Wet Flue Gas Desulphurization Pilot Plant DEFF Research Database (Denmark) Hansen, Brian Brun; Kiil, Søren 2012-01-01 of impurities (0.002 M Al2F6; 50 g quartz/L; 0.02 M Al3+, and 0.040 M Mg2+) were investigated. In addition, slurry from a full-scale wet FGD plant, experiencing formation of flat shaped crystals and poor gypsum dewatering properties, was transferred to the pilot plant to test if the plant would now start...... to time. In this work, the particle size distribution, morphology, and filtration rate of wet FGD gypsum formed in a pilot-scale experimental setup, operated in forced oxidation mode, have been studied. The influence of holding tank residence time (10–408 h), solids content (30–169 g/L), and the presence...... to produce low quality gypsum. The crystals formed in the pilot plant, on the basis of the full-scale slurry did, however, show acceptable filtration rates and crystal morphologies closer to the prismatic crystals from after pilot plant experiments with demineralized water. The gypsum slurry filtration rates... 11. Use of Flue Gas Desulfurization (FGD) Gypsum as a Heavy Metal Stabilizer in Contaminated Soils Science.gov (United States) Flue Gas Desulfurization (FGD) gypsum is a synthetic by-product generated from the flue gas desulfurization process in coal power plants. It has several beneficial applications such as an ingredient in cement production, wallboard production and in agricultural practice as a soil... 12. Development of a self-compacting gypsum-based lightweight composite NARCIS (Netherlands) Yu, Q.; Brouwers, H.J.H. 2012-01-01 This article addresses experiments and theories of a self-compacting gypsum-based lightweight composite (SGLC). A ß-hemihydrate is used as binder and lightweight aggregate (LWA, 0–2 mm in different size ranges) is used as aggregate into this composite. The mix of the new composite is designed based 13. Composition of gypsum from the Koběřice quarry (Czech Republic) Czech Academy of Sciences Publication Activity Database Konečný, Pavel; Plevová, Eva; Vaculíková, Lenka; Kožušníková, Alena; Peterková, J.; Hundáková, M. 2011-01-01 Roč. 8, č. 2 (2011), s. 145-156 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30860518 Keywords : gypsum * Kobeřice quarry * spectroscopy Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/abstracts/AGG/02_11/5_Konecny.pdf 14. Morphology and stability of aggregates of an Oxisol according to tillage system and gypsum application Directory of Open Access Journals (Sweden) Fábio Régis de Souza 2012-12-01 Full Text Available Morphological characterization and aggregate stability is an important factor in evaluating management systems. The aim of this paper is to evaluate the stability and morphology of the aggregates of a dystrophic Oxisol managed with no-tillage and conventional tillage with and without the residual action of gypsum. The experimental design was randomized blocks arranged in split-split plot, where the treatments were two soil management systems (plots with 0 and 2000 kg ha-1 of gypsum (subplots and five depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20 and 0.20-0.30 m as the subsubplots, with four replications. The aggregate morphology was determined through images and later evaluated by the Quantporo software. Stability was determined by the wet method. The results showed that the no-tillage system, with or without gypsum residual effect, provided the aggregates with the largest geometric diameters. The combination of no-tillage system and the gypsum residual effect provided rougher aggregates. 15. Two distinctive new species of Commicarpus (Nyctaginaceae) from gypsum outcrops in eastern Ethiopia DEFF Research Database (Denmark) Friis, Ib; Gilbert, Michael G.; Weber, Odile 2016-01-01 During field trips in 2013 and 2014, two distinctive plants belonging to the genus Commicarpus were collected in the Lele Hills, Bale Zone, eastern Ethiopia, on outcrops of sedimentary rock belonging to the Gorrahei Formation with high contents of gypsum. The plants are here described as two new... 16. Microbial Volatile Organic Compound Emissions from Stachybotrys chartarum growing on Gypsum Wallboard and Ceiling tile Science.gov (United States) This study compared seven toxigenic strains of S. chartarum found in water-damaged buildings to characterize the microbial volatile organic compound (MVOC) emissions profile while growing on gypsum wallboard (W) and ceiling tile (C) coupons. The inoculated coupons with their sub... 17. Palaeoclimatic significance of gypsum pseudomorphs in the inner shelf sediments off Machalipatnam bay Digital Repository Service at National Institute of Oceanography (India) Rao, V.P. Pseudo-gypsum crystals have been found in the coarse fraction of the sediments from the inner continental shelf off Machilipatnam Bay. They range in size from 3 to 7 mm are elongate and lenticular in shape. Bassanite and calcite are pseudomorphs... 18. Results using flue gas desulfurization gypsum in soilless substrates for greenhouse crops Science.gov (United States) Recent availability of Flue Gas Desulfurization gypsum (FGDG) has led to interested in its possible use in horticulture greenhouse production. Three studies were conducted to determine the effects of increasing rates of FGDG on six greenhouse crops. In the first study, substrates (6:1 pine bark:san... 19. Assessment of Mercury in Soils, Crops, Earthworms, and Water when Soil is Treated with Gypsum Science.gov (United States) Flue gas desulfurization (FGD) gypsum from fossil fuel combustion has many potential uses in agriculture, but there is concern about the potential environmental effects of its elevated mercury (Hg) concentration. The wet limestone scrubbing process that removes sulfur from flue gas (and produces gyp... 20. Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss Science.gov (United States) Relative to fresh broiler litter, little is known about the dynamics of composted litter derived-nutrient in the ecosystem. In this study, the potential leaching losses of nutrients from compost relative to fresh broiler litter along with flue gas desulfurization (FGD gypsum), as a nutrient immobil... 1. Characterization of gypsum crystals exposed to a high CO2 concentration fog using x-ray International Nuclear Information System (INIS) Carreño-Márquez, I. J. A.; Castillo-Sandoval, I.; Esparza-Ponce, H. E.; Fuentes-Cobas, L.; Montero-Cabrera, M. E. 2015-01-01 In Chihuahua State, a little town called Naica has the largest gypsum single crystals in the world. The growth of these structures has been described as a long and stable process developed over thousands of years. Due to the change in the environmental conditions, these crystals could suffer alterations on their surface. In this project we study the cause of possible deterioration of the giant crystals and intend to suggest measures for their preservation. For this sake, our first experiment consists on several gypsum crystals that have been subjected in a climate chamber to a fog at high CO 2 concentration and 51 °C for a period of time of six months, extracting two crystals every 15 days. Then the crystals have been characterized through Grazing Incidence X-Ray Diffraction using a diffractometer PanAlytical X’PertPro with two different detectors; Xe-filled proportional detector and a Pixel 3D detector. The results were compared to determine which technique is the most suitable to study the degradation of gypsum single crystals. In the two cases, we have identified only the gypsum phase, but with different crystal plane orientations 2. Inflammatory potential of low doses of airborne fungi from fungal infested damp and dry gypsum boards DEFF Research Database (Denmark) Knudsen, Sofie Marie; Gunnarsen, Lars Bo; Madsen, Anne Mette 2017-01-01 chrysogenum. Bacillus infantis and Paenibacillus sp. were found on the gypsum boards, but not recovered in the aerosols. A significant correlation was found between the TIP of diluted and undiluted samples of fungal aerosols. However, diluted samples had a higher TIP than undiluted samples, and no significant... 3. Flue gas desulfurization gypsum: Its effectiveness as an alternative bedding material for broiler production Science.gov (United States) Flue gas desulfurization gypsum (FGDG) may be a viable low-cost alternative bedding material for broiler production. In order to evaluate FGD gypsum’s viability, three consecutive trials were conducted to determine its influence on live performance (body weight, feed consumption, feed efficiency, an... 4. Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure Science.gov (United States) Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu 2017-08-01 The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually 5. Effect of temperature and concentration principle on gypsum scaling in desalination units International Nuclear Information System (INIS) Ben Ahmed, Samia; Tlili, Mohamed; Ben Amor, Mohamed 2009-01-01 Tunisia (North Africa) is currently confronted to the crucial problem of the public, agricultural and industrial feed water supply, in particular in the center and south areas. Production of fresh water by seawater and brackish water desalination has proved to be an alternative for these regions. However, all the desalination processes are based on the concentration principle of waters already presented higher salinity. So, scale problem can occurs by the accumulation of minerals such as CaCO 3 and CaSO 4 . These salts form hard and strongly adhering deposits on the surfaces and their formation is favoured by the decrease of their solubility with increasing temperature. The main object of this investigation is the study and the control of calcium sulphate deposition causes and conditions in the thermal desalination plant. For this purpose, the effect of different water temperatures (30-90 degree) and saturation states (3-10), on homogeneous nucleation and growth of gypsum, variety usually met, was examined. Gypsum was precipitated by mixing aqueous CaCl 2 and Na 2 SO 4 solutions. It was found that, with increasing temperature or supersaturation, the induction time decreases and the growth rate increases. At the same saturation state, the effect of temperature on reducing induction time is more significant for T<50 degree whereas the growth rate of gypsum crystals is more influenced when the temperature exceeds 50 degree. This value can be considered as a critical temperature; once reached the gypsum scaling threat becomes serious. By using classical nucleation theory, the interfacial tension and the nucleation rate values were estimated. It was shown that the interfacial tension is, as well, temperature dependent. The calculation of nucleation rate showed that: i) by increasing temperature, the number of formed nuclei does not change. The effect of this parameter is limited at the kinetic of formation and growth of these nuclei, ii) the water concentration 6. IMPACT OF NANOMODIFIERS ON MECHANICAL AND PHYSICAL PROPERTIES OF GYPSUM BINDERS Directory of Open Access Journals (Sweden) DEREVIANKO V. N. 2017-02-01 Full Text Available Summary. Problem statement. In the next 10 years, more than 90% of materials will be replaced with new materials – nanocomposites [1]. The nanocomponents application will allow manufacture of high-strength materials with reduced production cost and will ensure demand for products [2]. Researches aimed to determination of carbon nanotube type nanomodifier concentration impact on the physical and mechanical properties of gypsum binders are important today and must result in creation of competitive strong nano-materials. Purpose. Research of carbon nanotube (CNT type nanomodifier concentration impact on the physical and mechanical properties of gypsum binders. Conclusion. Sample microstructure analysis revealed that the non-modified gypsum sample structure is dominated by prismatic and lamellar crystals randomly distributed throughout the matrix volume. In this case, loose structure with increased porosity is formed, which results in sample mechanical strength reduction. In the CNT-modified gypsum matrix, well-ordered and homogeneous structure is formed with larger needle-shaped crystals, which results in the phase-contacting area increase, porosity reduction and thus the physical and mechanical characteristics improvement. It is experimentally proved that at the identical nano-modifier content in the gypsum matrix (0.035 %, maximum compression strength gain is achieved with the use of CNT and makes 28- 30%. At the use of initial carbon nanotubes, increase in strength at the same nano-modifier content makes 13-15%. The Ca2+ ions interaction with the graphene-like carbon surface was investigated by the DFT method. Capability is demonstrated of the covalent calcium bonding with the hexagonal carbon surface cell as a result of overlap of Ca2+ valence 3p orbitals and carbon 2р orbitals. 7. Location of quarries of magnesian lime used as raw material of Roman plasters in western Lombardy (Italy Directory of Open Access Journals (Sweden) Roberto Bugini 2017-01-01 Full Text Available Lime as building material was widely diffused in Roman architecture of western Lombardy. The presence of magnesite (magnesium carbonate was detected in painted plasters coming from roman sites of Milano: magnesite indicates the use of dolomite to make the lime. Dolomite rocks widely outcrop in the Lombard Prealps: light grey dolomites and dolomitic limestones (Dolomia del Salvatore, Ladinian-Anisian; grey dolomites, sometimes with cyclothemes (Dolomia Principale, Norian. There is no evidence of Roman lime quarries or kilns in this area; the Romans probably exploited the same dolomite outcrops, located along the eastern shore of lake Maggiore, where lime was produced from the Middle Ages onwards. The glacio-fluvial deposits of the middle course of the river Adda (cobbles, pebbles of siliceous limestone together with limestone and dolomite outcropping in the river basin were another medieval and modern source of raw material, mainly to make a moderately hydraulic lime (called “calce forte”, but this kind of lime is lacking in Roman plasters. 8. Soil fertility, nutrition and yield of maize and barley with gypsum application on soil surface in no-till Directory of Open Access Journals (Sweden) Leandro Michalovicz 2014-10-01 Full Text Available Annual crop yield and nutrition have shown differentiated responses to modifications in soil chemical properties brought about by gypsum application. The aim of this study was to evaluate the effect of gypsum application rates on the chemical properties of a Latossolo Bruno (Clayey Oxisol, as well as on the nutrition and yield of a maize-barley succession under no-till. The experiment was set up in November 2009 in Guarapuava, Parana, Brazil, applying gypsum rates of 0.0, 1.5, 3.0, 4.5, and 6.0 Mg ha-1 to the soil surface upon sowing maize, with crop succession of barley. Gypsum application decreased the levels of Al3+ and Mg2+ in the 0.0-0.1 m layer and increased soil pH in the layers from 0.2-0.6 m depth. Gypsum application has increased the levels of Ca2+ in all soil layers up to 0.6 m, and the levels of S-SO4(2- up to 0.8 m. In both crops, the leaf concentrations of Ca and S were increased while Mg concentrations have decreased as a function of gypsum rates. There was also an effect of gypsum rates on grain yield, with a quadratic response of maize and a linear increase for barley. Yield increases were up to 11 and 12 % in relation to control for the maximum technical efficiency (MTE rates of 3.8 and 6.0 Mg ha-1 of gypsum, respectively. Gypsum application improved soil fertility in the profile, especially in the subsurface, as well as plant nutrition, increasing the yields of maize and barley. 9. Crop Response to Gypsum Application to Subtropical Soils Under No-Till in Brazil: a Systematic Review Directory of Open Access Journals (Sweden) Tales Tiecher 2018-02-01 Full Text Available ABSTRACT The use of gypsum to improve the root environment in tropical soils in the southeastern and central-western regions of Brazil is a widespread practice with well-established recommendation criteria. However, only recently gypsum began to be used on subtropical soils in South of Brazil, so available knowledge of its effect on crop yield is incipient and mainly for soils under no-till (NT systems. Avaiable studies span a wide range of responses, from a substantial increase to a slight reduction in crop yield. Also, the specific conditions leading to a favorable effect of gypsum application on crop yield are yet to be accurately identified. The primary objectives of this study were to examine previously reported results to assess the likelihood of a crop response to gypsum and to develop useful recommendation criteria for gypsum application to subtropical soils under NT in Brazil. For this purpose, we examined the results of a total of 73 growing seasons, reported in 20 different scientific publications that assessed grain yield as a function of gypsum rates. Four different scenarios were examined, by the occurrence or not of high subsurface acidity (viz., Al saturation >20 % and/or exchangeable Ca 3 cmolc dm-3 failed to increase crop yield, irrespective of the soil water status. Under these conditions, high gypsum rates (6-15 Mg ha−1 may even reduce grain yield, possibly by inducing K and Mg deficiency. On the other hand, applying gypsum to soils with high subsurface acidity increased yield by 16 % in corn (87 % of cases and by 19 % in winter cereals (83 % of cases, whether or not the soil was water-deficient. By contrast, soybean yield was only increased by gypsum applied in the simultaneous presence of high soil subsurface acidity and water deficiency (average increase 27 %, 100 % of cases. 10. Effect of amino acids on the precipitation kinetics and Ca isotopic composition of gypsum Science.gov (United States) Harouaka, Khadouja; Kubicki, James D.; Fantle, Matthew S. 2017-12-01 Stirred gypsum (CaSO4 · 2H2O) precipitation experiments (initial Ωgypsum = 2.4 ± 0.14, duration ≈ 1.0-1.5 h) were conducted in the presence of the amino acids glycine (190 μM), L-alanine (190 μM), D- and L-arginine (45 μM), and L-tyrosine (200 μM) to investigate the effect of simple organic compounds on both the precipitation kinetics and Ca isotopic composition of gypsum. Relative to abiotic controls, glycine, tyrosine, and alanine inhibited precipitation rates by ∼22%, 27%, and 29%, respectively, while L- and D-arginine accelerated crystal growth by ∼8% and 48%, respectively. With the exception of tyrosine, amino acid induced inhibition resulted in fractionation factors (αs-f) associated with precipitation that were no more than 0.3‰ lower than amino acid-free controls. In contrast, the tyrosine and D- and L-arginine experiments had αs-f values associated with precipitation that were similar to the controls. Our experimental results indicate that Ca isotopic fractionation associated with gypsum precipitation is impacted by growth inhibition in the presence of amino acids. Specifically, we propose that the surface-specific binding of amino acids to gypsum can change the equilibrium fractionation factor of the bulk mineral. We investigate the hypothesis that amino acids can influence the growth of gypsum at specific crystal faces via adsorption and that different faces have distinct fractionation factors (αface-fluid). Accordingly, preferential sorption of amino acids at particular faces changes the relative, face-specific mass fluxes of Ca during growth, which influences the bulk isotopic composition of the mineral. Density functional theory (DFT) calculations suggest that the energetic favorability of glycine sorption onto gypsum crystal faces occurs in the order: (1 1 0) > (0 1 0) > (1 2 0) > (0 1 1), while glycine sorption onto the (-1 1 1) face was found to be energetically unfavorable. Face-specific fractionation factors constrained by 11. In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature Institute of Scientific and Technical Information of China (English) LIU Chuan-Jiang; ZHENG Hai-Fei 2012-01-01 An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa.With increasing temperature,the anhydrite (CaSO4) phase precipitates at 250 320℃ in the pressure range of 1.0 1.5 GPa,indicating that under a saturated water condition,both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite.A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) =0.0068T - 0.7126 (250℃≤T≤320℃).Anhydrite remained stable during rapid cooling of the sample chamber,showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.%An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 Mpa. With increasing temperature, the anhydrite (CaSO4) phase precipitates at 250-320℃ in the pressure range of 1.0-1.5 Gpa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(Gpa) = 0.0068T - 0.7126 (250℃≤T≤320℃). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is 12. Gypsum (CaSO42H2O) scaling on polybenzimidazole and cellulose acetate hollow fiber membranes under forward osmosis KAUST Repository Chen, Si Cong; Su, Jincai; Fu, Feng-Jiang; Mi, Baoxia; Chung, Neal Tai-Shung 2013-01-01 We have examined the gypsum (CaSO42H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI 13. Study of the rheological properties of casting slips obtained from titanium oxide and bariun titanate in order to obtain pieces by means of casting in plaster moulds International Nuclear Information System (INIS) Amarante Junior, A. 1986-01-01 The behaviour of titanium-oxide (TiO 2 ) and barium titanate used in slip casting with plaster moulds is studied. Some data in several tests, as well as materials and methods applied are presented. (M.J.C.) [pt 14. Dehydration reactions of gypsum: A neutron and X-ray diffraction study Science.gov (United States) Abriel, W.; Reisdorf, K.; Pannetier, J. 1990-03-01 The kinetics of the dehydration of gypsum was investigated by powder diffraction methods. Using the incoherent scattering effect of H with the neutron beam, the background intensity as a measure of the water content was checked in the temperature range 295-623 K. The superposed Bragg peaks yielded four major phases: Gypsum, subhydratesCaSO 4(H 2O) x (1 > x > 0),AIII-CaSO 4, AII-CaSO 4. For the subhydrates a maximum water content of x > = 0.74was determined. A different kinetic was found using Guinier X-ray technique with the heated sample prepared on a thin foil. Only with high local H 2O steam pressure, produced in the comparable larger sample container of the neutron diffraction experiment, could this high H 2O occupation of the subhydrate tunnel structure be found. A topotactic mechanism can describe the phase transitions for this reaction. 15. Radioecology of and radiation dose from Dutch waste gypsum released into the environment International Nuclear Information System (INIS) Koster, H.W.; Weers, A.W. van; Netherlands Energy Research Foundation, Petten) 1985-11-01 The Dutch industries release 9 kinds of waste gypsum, 90% of the total quantity is phosphogypsum. Only waste gypsums from the phosphate industries show increased radioactivity, the strongest in phosphogypsum. All phosphogypsum, 2 Tg.a -1 , is disposed of into the Rhine at Rotterdam. This leads to an increase of radionuclides, from the U-238 chain, along the Dutch coast. The calculated increase of activity concentrations in sea food causes an increase of the individual radiation dose of maximal 150 μSv.a -1 and of the Dutch population dose of 170 manSv.a -1 . Stacking of the phosphogypsum would result in a dose increase of one order of magnitude lower. The need for environmental disposal or stacking of at least the fine and coarse fractions of the phosphogypsum, which are difficult to recycle, will remain. (Auth.) 16. Thermal Dehydration Kinetics of Gypsum and Borogypsum under Non-isothermal Conditions Institute of Scientific and Technical Information of China (English) I.Y.Elbeyli; S.Piskin 2004-01-01 Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides. 17. Influence of the gypsum dehydration temperature and alkali additives on the properties of anhydrite cement Directory of Open Access Journals (Sweden) Leskeviciene V. 2010-01-01 Full Text Available While dehydrating gypsum with additives at the temperatures of 800°C and 900°C the influence of alkali additives on both the crystalline structure of anhydrite and properties of anhydrite binder was investigated. The industrial and household wastes including other lowcost materials were used as additives. Having heated them with gypsum the anhydrite with alkali activation properties was obtained. The properties of such substances were evaluated using the methods of chemical, diffractive X-ray scanning and scanning electron microscopy (SEM analyses. Some additives, e.g. 5 % ground glass waste, were found to increase crystal agglomerate formation of anhydrite binder, accelerate the hydration process of anhydrite and double the compressive strength of hydrated samples compared to samples without additives. 18. Influence of Flue Gas Desulfurization Gypsum on Reducing Soluble Phosphorus in Successive Runoff Events from a Coastal Plain Bermudagrass Pasture. Science.gov (United States) Watts, Dexter B; Torbert, H Allen 2016-05-01 Controlling the threat that pastures intensively managed with poultry litter (PL) pose to accelerating eutrophication is a major issue in the southeastern United States. Gypsum (CaSO) has been identified as a promising management tool for ameliorating litter P losses to runoff. Thus, research was conducted to elucidate gypsum's residual effects on P losses from a bermudagrass ( L.) pasture. Runoff events (60 min) were created using rainfall simulations. Treatments consisted of applying four flue gas desulfurization (FGD) gypsum rates (0, 2.2, 4.4, and 8.9 Mg ha) to bermudagrass fertilized with 13.4 Mg ha PL plus a nonfertilized check (no litter or gypsum) and 8.9 Mg ha FGD gypsum only as controls. Rainfall simulations (∼ 85 mm h) were conducted immediately, 5 wk, and 6 mo (i.e., at the end of growing season) after PL application to determine gypsum's effectiveness at controlling P loss over successive runoff events. The greatest dissolved P (DP) in runoff occurred immediately after PL application. Gypsum effectively reduced cumulative DP concentration losses (54%) compared with PL alone in initial runoff events. Gypsum reduced DP concentrations in succeeding runoff events also regardless of timing, suggesting that its effect is persistent and will not diminish over a growing season. Generally, maximum DP reductions were achieved with 8.9 Mg ha. However, it was surmised from this study that optimal P reduction in a bermudagrass pasture can be achieved with 4.4 Mg ha. Information ascertained from this study may be useful in aiding land managers making prescriptions for management practices that reduce DP losses from agricultural fields. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc. 19. The effect of gypsum products and separating materials on the typography of denture base materials. Science.gov (United States) Firtell, D N; Walsh, J F; Elahi, J M 1980-09-01 The typography of polymethyl methacrylate processed against various gypsum products coated with various separating materials was studied under an SEM. Tinfoil and two commercial tin foil substitutes were used as separating material during processing, and the surfaces of the resulting acrylic resin forms were studied for topographical differences. Tinfoil and alpha 2 hemihydrates produced the smoothest surfaces. As a practical solution, a good quality tinfoil substitute and alpha 1 hemihydrate could be used when processing polymethyl methacrylate resin. 20. Elementary characterization of samples of Portland cement, natural gypsum and phosphogypsum mortars from Brazil Energy Technology Data Exchange (ETDEWEB) Narloch, Danielle Cristine; Paschuk, Sergei Anatolyevich; Corrêa, Janine Nicolosi; Torres, Catarina Alzira Peddis; Mazer, Wellington; Macioski, Gustavo [Universidade Tecnologica Federal do Parana (UTFPR), PR (Brazil); Lara, Alessandro [Universidade de Sao Paulo (USP), SP (Brazil). Departamento de Fisica; Casali, Juliana Machado, E-mail: [email protected], E-mail: [email protected], E-mail: [email protected] [Instituto Federal de Santa Catarina (IFSC), Florianópolis, SC (Brazil) 2017-07-01 Portland cement, the basic ingredient of concrete and is manufactured by crushing, milling and proportioning limestone, sand, clay, iron ore and secondary materials such as shells, chalk or marl combined with shale slate or blast furnace slag, fly ash, gypsum, phosphogypsum, and some others. Evaluating the physical and mineralogical characteristics of the cement and its chemical composition is essential to establish the quality of the product. Therefore, the objective of this work was to characterize and quantify the most common chemical elements in the samples of Brazilian Portland cement, natural gypsum, and phosphogypsum mortars by means of X-ray dispersive energy spectroscopy (EDXRF), as well as to evaluate the strength of these mortars. For analysis of the compressive strength, initially prepared samples were submitted to a destructive mechanical test. Subsequently samples were milled and compacted to form thin tablets, which were submitted to the EDXRF analysis. The qualitative and quantitative analyzes showed that for phosphogypsum mortar the largest mass fractions were found of 49.8±2.5% (Si), 24.66±0.96% (S) and 22.10±0.42% (Ca). For gypsum mortar those values were found of 43.41±0.45% (Ca), 33.8 ± 0.8% (S) and 18.9±1.2% (Si), respectively; and for Portland cement mortar, the predominant elements in those samples have the mass fractions of 64.20±0.52% (Ca) and 27.3±1.5% (Si). The results showed that obtained values of mass fraction of the elements Si, S, K, Ca, Ti, Fe are in rather good agreement with quantities indicated for manufacture. Besides, gypsum and phosphogypsum presented almost the same composition and compressive strength. (author) 1. Accuracy of Gypsum Casts after Different Impression Techniques and Double Pouring. Directory of Open Access Journals (Sweden) Stephania Caroline Rodolfo Silva Full Text Available This study evaluated the accuracy of gypsum casts after different impression techniques and double pouring. Ten patients were selected and for each one it was obtained 5 partial putty/wash impressions with vinyl polysiloxane (VPS material from teeth #13 to #16 with partial metal stock trays. The following techniques were performed: (1 one-step; two-step relief with: (2 PVC film; (3 slow-speed tungsten carbide bur and scalpel blade, (4 small movements of the tray and (5 without relief-negative control. The impressions were disinfected with 0.5% sodium hypochlorite for 10 minutes and stored during 110 and 230 minutes for the first and second pouring, respectively, with type IV gypsum. Three intra-oral lateral photographs of each patient were taken using a tripod and a customized radiographic positioner. The images were imported into ImageJ software and the total area of the buccal surface from teeth #13 to #16 was measured. A 4.0% coefficient of variance was criterion for using these measurements as Baseline values. The casts were photographed and analyzed using the same standardization for the clinical images. The area (mm2 obtained from the difference between the measurements of each gypsum cast and the Baseline value of the respective patient were calculated and analyzed by repeated-measures two way-ANOVA and Mauchly's Sphericity test (α = 0.05. No significant effect was observed for Impression technique (P = 0.23, Second pouring (P = 0.99 and their interaction (P = 0.25. The impression techniques and double pouring did not influence the accuracy of the gypsum casts. 2. Effect of alginate chemical disinfection on bacterial count over gypsum cast OpenAIRE Haralur, Satheesh B.; Al-Dowah, Omir S.; Gana, Naif S.; Al-Hytham, Abdullah 2012-01-01 PURPOSE To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. MATERIALS AND METHODS Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 21... 3. Elementary characterization of samples of Portland cement, natural gypsum and phosphogypsum mortars from Brazil International Nuclear Information System (INIS) Narloch, Danielle Cristine; Paschuk, Sergei Anatolyevich; Corrêa, Janine Nicolosi; Torres, Catarina Alzira Peddis; Mazer, Wellington; Macioski, Gustavo; Lara, Alessandro 2017-01-01 Portland cement, the basic ingredient of concrete and is manufactured by crushing, milling and proportioning limestone, sand, clay, iron ore and secondary materials such as shells, chalk or marl combined with shale slate or blast furnace slag, fly ash, gypsum, phosphogypsum, and some others. Evaluating the physical and mineralogical characteristics of the cement and its chemical composition is essential to establish the quality of the product. Therefore, the objective of this work was to characterize and quantify the most common chemical elements in the samples of Brazilian Portland cement, natural gypsum, and phosphogypsum mortars by means of X-ray dispersive energy spectroscopy (EDXRF), as well as to evaluate the strength of these mortars. For analysis of the compressive strength, initially prepared samples were submitted to a destructive mechanical test. Subsequently samples were milled and compacted to form thin tablets, which were submitted to the EDXRF analysis. The qualitative and quantitative analyzes showed that for phosphogypsum mortar the largest mass fractions were found of 49.8±2.5% (Si), 24.66±0.96% (S) and 22.10±0.42% (Ca). For gypsum mortar those values were found of 43.41±0.45% (Ca), 33.8 ± 0.8% (S) and 18.9±1.2% (Si), respectively; and for Portland cement mortar, the predominant elements in those samples have the mass fractions of 64.20±0.52% (Ca) and 27.3±1.5% (Si). The results showed that obtained values of mass fraction of the elements Si, S, K, Ca, Ti, Fe are in rather good agreement with quantities indicated for manufacture. Besides, gypsum and phosphogypsum presented almost the same composition and compressive strength. (author) 4. 18O and 34S in the Upper Bartonium gypsum deposits of the Paris basin International Nuclear Information System (INIS) Fontes, J.C.; Letolle, R. 1976-01-01 Isotopic analyses ( 18 O and 34 S) of the Eocene gypsum from the Paris basin show a range beyond the normal Tertiary marine values. The possibility of a reduction process during diagenesis is discussed. A hypothesis of continental origin by leaching of Permotriassic deposits is proposed for this formation on the basis of a comparison of the isotopic contents recorded from Germany and eastern France 5. Kinetics of oil saponification by lead salts in ancient preparations of pharmaceutical lead plasters and painting lead mediums. Science.gov (United States) Cotte, M; Checroun, E; Susini, J; Dumas, P; Tchoreloff, P; Besnard, M; Walter, Ph 2006-12-15 Lead soaps can be found in archaeological cosmetics as well as in oil paintings, as product of interactions of lead salts with oil. In this context, a better understanding of the formation of lead soaps allows a follow-up of the historical evolution of preparation recipes and provides new insights into conservation conditions. First, ancient recipes of both pharmaceutical lead plasters and painting lead mediums, mixtures of oil and lead salts, were reconstructed. The ester saponification by lead salts is determined by the preparation parameters which were quantified by FT-IR spectrometry. In particular, ATR/FT-IR spectrometer was calibrated by the standard addition method to quantitatively follow the kinetics of this reaction. The influence of different parameters such as temperature, presence of water and choice of lead salts was assessed: the saponification is clearly accelerated by water and heating. This analysis provides chemical explanations to the historical evolution of cosmetic and painting preparation recipes. 6. Mechanical properties of simulated Mars materials: gypsum-rich sandstones and lapilli tuff Science.gov (United States) Morrow, Carolyn; Lockner, David; Okubo, Chris 2013-01-01 Observations by the Mars Exploration Rover (MER) Opportunity, and other recent studies on diagenesis in the extensive equatorial layered deposits on Mars, suggest that the likely lithologies of these deposits are gypsum-rich sandstones and tuffaceous sediments (for example, Murchie and others, 2009; Squyres and others, 2012; Zimbelman and Scheidt, 2012). Of particular interest is how the diagenesis history of these sediments (degree of cementation and composition) influences the strength and brittle behavior of the material. For instance, fractures are more common in lower porosity materials under strain, whereas deformation bands, characterized by distributed strain throughout a broader discontinuity in a material, are common in higher porosity sedimentary materials. Such discontinuities can either enhance or restrict fluid flow; hence, failure mode plays an important role in determining the mechanics of fluid migration through sediments (Antonellini and Aydin, 1994; 1995; Taylor and Pollard, 2000; Ogilvie and Glover, 2001). As part of a larger study to characterize processes of fault-controlled fluid flow in volcaniclastic and gypsum-rich sediments on Mars, we have completed a series of laboratory experiments to focus on how gypsum clast content and degree of authigenic cementation affects the strength behavior of simulated Mars rocks. Both axial deformation and hydrostatic pressure tests were done at room temperature under dry conditions. 7. Clay stabilization by using gypsum and paddy husk ash with reference to UCT and CBR value Science.gov (United States) Roesyanto; Iskandar, R.; Hastuty, I. P.; Dianty, W. O. 2018-02-01 Clays that have low shear strength need to be stabilized in order to meet the technical requirements to serve as a subgrade material. One of the usual soil stabilization methods is by adding chemicals such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and paddy husk ash. The research goals were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% paddy husk ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT value of original soil was 1.41 kg/cm2. While the CBR soaked and unsoaked values of original soil were 4.41% and 6.23% respectively. The research results showed the addition of paddy husk ash decreased the value of unconfined compressive strength as well as CBR. The stabilized soil by 2% gypsum and 0% paddy husk ash gave maximum UCT value of 1.67 kg/cm2, while the maximum value of CBR were found 6.71% for CBR soaked and 8.00% for CBR unsoaked. The addition of paddy husk ash did not alter the soil classification according to AASHTO or USCS, even degrade the engineering properties of original soil. 8. Developing biodiversity indicators on a stakeholders' opinions basis: the gypsum industry Key Performance Indicators framework. Science.gov (United States) Pitz, Carline; Mahy, Grégory; Vermeulen, Cédric; Marlet, Christine; Séleck, Maxime 2016-07-01 This study aims to establish a common Key Performance Indicators (KPIs) framework for reporting about the gypsum industry biodiversity at the European level. In order to integrate different opinions and to reach a consensus framework, an original participatory process approach has been developed among different stakeholder groups: Eurogypsum, European and regional authorities, university scientists, consulting offices, European and regional associations for the conservation of nature, and the extractive industry. The strategy is developed around four main steps: (1) building of a maximum set of indicators to be submitted to stakeholders based on the literature (Focus Group method); (2) evaluating the consensus about indicators through a policy Delphi survey aiming at the prioritization of indicator classes using the Analytic Hierarchy Process method (AHP) and of individual indicators; (3) testing acceptability and feasibility through analysis of Environmental Impact Assessments (EIAs) and visits to three European quarries; (4) Eurogypsum final decision and communication. The resulting framework contains a set of 11 indicators considered the most suitable for all the stakeholders. Our KPIs respond to European legislation and strategies for biodiversity. The framework aims at improving sustainability in quarries and at helping to manage biodiversity as well as to allow the creation of coherent reporting systems. The final goal is to allow for the definition of the actual biodiversity status of gypsum quarries and allow for enhancing it. The framework is adaptable to the local context of each gypsum quarry. 9. Risk minimisation of FGD gypsum leachates by incorporation of aluminium sulphate Energy Technology Data Exchange (ETDEWEB) Alvarez-Ayuso, E. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain); Department of Environmental Geochemistry, IRNASA, CSIC, Apto. 257, 37071 Salamanca (Spain)], E-mail: [email protected]; Querol, X. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain); Ballesteros, J.C.; Gimenez, A. [Endesa Generacion, S.A., C/ Ribera de Loira, 60, 28042 Madrid (Spain) 2008-11-15 The incorporation of aluminium sulphate to (flue gas desulphurisation) FGD gypsum before its disposal was investigated as a way to minimise the risk supposed by the high fluoride content of its leachates. Using a bath method the kinetic and equilibrium processes of fluoride removal by aluminium sulphate were studied at fluoride/aluminium molar concentration (F/Al) ratios in the range 1.75 10{sup -2}-1.75 under the pH conditions (about 6.5) of FGD gypsum leachates. It was found that fluoride removal was a very fast process at any of the (F/Al) ratios subject of study, with equilibrium attained within the first 15 min of interaction. High decreases in solution fluoride concentrations (50-80%) were found at the equilibrium state. The use of aluminium sulphate in the stabilization of FGD gypsum proved to greatly decrease its fluoride leachable content (in the range 20-90% for aluminium sulphate doses of 0.1-5%, as determined by the European standard EN 12457-4). Such fluoride leaching minimisation assures the characterization of this by-product as a waste acceptable at landfills for non-hazardous wastes according to the Council Decision 2003/33/EC on waste disposal. Furthermore, as derived from column leaching studies, the proposed stabilization system showed to be highly effective in simulated conditions of disposal, displaying fluoride leaching reduction values about 55 and 80% for aluminium sulphate added amounts of 1 and 2%, respectively. 10. In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature International Nuclear Information System (INIS) Liu Chuan-Jiang; Zheng Hai-Fei 2012-01-01 An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa. With increasing temperature, the anhydrite (CaSO 4 ) phase precipitates at 250–320°C in the pressure range of 1.0–1.5GPa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO 4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) = 0.0068T−0.7126 (250°C≤T≤320°C). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature. (geophysics, astronomy, and astrophysics) 11. Implications of moisture content determination in the environmental characterisation of FGD gypsum for its disposal in landfills Energy Technology Data Exchange (ETDEWEB) Alvarez-Ayuso, E. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris s/n, 08028 Barcelona (Spain)], E-mail: [email protected]; Querol, X. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris s/n, 08028 Barcelona (Spain); Tomas, A. [Endesa Generacion, S.A., C/ Ribera de Loira 60, 28042 Madrid (Spain) 2008-05-01 The leachable contents of elements of environmental concern considered in the Council Decision 2003/33/EC on waste disposal were determined in flue gas desulphurisation (FGD) gypsum. To this end, leaching tests were performed following the standard EN-12457-4 which specifies the determination of the dry mass of the material at 105 deg. C and the use of a liquid to solid (L/S) ratio of 10 l kg{sup -1} dry matter. Additionally, leaching tests were also carried out taking into account the dry mass of the material at 60 deg. C and using different L/S ratios (2, 5, 8, 10, 15 and 20 l kg{sup -1} dry matter). It was found that the dry mass determination at 105 deg. C turns out to be inappropriate for FGD gypsum since at this temperature gypsum transforms into bassanite, and so, in addition to moisture content, crystalline water is removed. As a consequence the moisture content is overvalued (about 16%), what makes consider a lower L/S ratio than that specified by the standard EN-12457-4. As a result the leachable contents in FGD gypsum are, in general, overestimated, what could lead to more strict environmental requirements for FGD gypsum when considering its disposal in landfills, specially concerning those elements (e.g., F) risking the characterisation of FGD gypsum as a waste acceptable at landfills for non-hazardous wastes. 12. Experimental study of thermal properties of a new ecological building material based on peanut shells and plaster Directory of Open Access Journals (Sweden) M. Lamrani 2017-12-01 Full Text Available The aim of the present work was to investigate the thermal properties of a new building material consisting of a mixture of plaster and peanut shells for use as insulating materials in building. The properties are commonly measured by using the steady state asymmetric hot plate method, the asymmetrical transient hot plate method and the flash method. The experimental study that we have conducted, enabled us to determine the conductivity, the effusivity and the thermal diffusivity of our material. The influence of the size and the mass fraction of the peanut shell shards on thermophysical properties of tested material, was investigated. Our experimental data show a good efficiency and a significant decrease in the thermal conductivity of material with peanut shell shards compared to simple plaster material. The purpose is to obtain ecological composite materials with better thermal performance, which can contribute to improve the thermal comfort in constructions in Morocco. The results show that the density of the new material was not substantially influenced by the size of the peanut shell shards. However, the thermal conductivity and diffusivity decrease from 0.3 Wm−1 K−1 and 3.75 × 10−7 m2 s−1 to 0.14 Wm−1 K−1 and 2.11 × 10−7m2 s−1, respectively, according to the variation of the mass fraction of peanut from 0 to20%. 13. Classification of multi-layered plaster in St. Abbondio Cloister at Como, Italy: an analytical tool for architectural archaeology Directory of Open Access Journals (Sweden) Sansonetti, A. 2006-06-01 Full Text Available St. Abbondio, at Como, Italy, is one of the most outstandingRomanesque basilicas in Northern Italy. Theentire building, and particularly the cloister, has beenthe object of a number of restorations over the centuries,as well as a significant conservation endeavourconducted between 2000 and 2003. In the in-depthdiagnostic survey undertaken on that occasion, thecomposition and morphology of the plaster in bothinteriors and exteriors were determined to obtain furtherinsight into the history of the cloister and its conservation.Plaster representative of the various phasesof construction were characterized with techniquessuch as powder X-ray diffraction, mercury intrusionporosimetry, thin section optical microscopy and atomicspectrometry. As a result of these analyses, groupsof samples with similar characteristics could be identified,confirming historiographic hypotheses on thesequence of the restoration and conservation workdone on the building and establishing a possible toolfor architectural archaeology.S. Abbondio (Como, Italia es una de las mas extraordinariasbasilicas romanicas presentes en el norte de Italia.El edificio entero y en particular el claustro ha sido expuestoa varias intervenciones durante los ultimos siglos, enparticular los ultimos trabajos de conservacion ejecutadosentre los anos 2000 y 2003. En esta ocasion se ha efectuadouna vasta campana diagnostica sobre los revoquestanto internos como externos, destinada a clasificarlosdesde el punto de vista compositivo-morfologico y paradescubrir la historia sobre la conservacion del claustro.Revoques representativos de las diferentes fases constructivashan sido identificados con la utilizacion de metodoscomo el analisis de difraccion de rayos X en polvo,porosimetria por intrusion de mercurio, microscopia opticapara secciones finas y espectrometria atomica. Losresultados han permitido agrupar las muestras que presentabancaracteristicas similares, confirmando hipotesishistoricas sobre la 14. Groundwater flow and its effect on salt dissolution in Gypsum Canyon watershed, Paradox Basin, southeast Utah, USA Science.gov (United States) Reitman, Nadine G.; Ge, Shemin; Mueller, Karl 2014-09-01 Groundwater flow is an important control on subsurface evaporite (salt) dissolution. Salt dissolution can drive faulting and associated subsidence on the land surface and increase salinity in groundwater. This study aims to understand the groundwater flow system of Gypsum Canyon watershed in the Paradox Basin, Utah, USA, and whether or not groundwater-driven dissolution affects surface deformation. The work characterizes the groundwater flow and solute transport systems of the watershed using a three-dimensional (3D) finite element flow and transport model, SUTRA. Spring samples were analyzed for stable isotopes of water and total dissolved solids. Spring water and hydraulic conductivity data provide constraints for model parameters. Model results indicate that regional groundwater flow is to the northwest towards the Colorado River, and shallow flow systems are influenced by topography. The low permeability obtained from laboratory tests is inconsistent with field observed discharges, supporting the notion that fracture permeability plays a significant role in controlling groundwater flow. Model output implies that groundwater-driven dissolution is small on average, and cannot account for volume changes in the evaporite deposits that could cause surface deformation, but it is speculated that dissolution may be highly localized and/or weaken evaporite deposits, and could lead to surface deformation over time. 15. Fabrication and properties of microencapsulated-paraffin/gypsum-matrix building materials for thermal energy storage International Nuclear Information System (INIS) Su Junfeng; Wang Xinyu; Wang Shengbao; Zhao Yunhui; Huang Zhen 2012-01-01 Graphical abstract: DSC curves of microPCMs/gypsum composite samples before and after a thermal cycling treatment. Highlights: ► Microcapsules containing paraffin was fabricated by in-situ polymerization. ► Methanol-modified melamine–formaldehyde (MMF) was used as shell material. ► MicroPCMs/gypsum-matrix building materials were applied for solar energy storage. ► The structure and thermal conductivity of composites had been investigated. - Abstract: Microencapsulated phase change materials (microPCMs) have been widely applied in solid matrix as thermal-storage or temperature-controlling functional composites. The aim of this work was to prepare and investigate the properties of microPCMs/gypsum-matrix building materials for thermal energy storage. MicroPCMs contain paraffin was fabricated by in situ polymerization using methanol-modified melamine–formaldehyde (MMF) as shell material. A series of microPCMs samples were prepared under emulsion stirring rates in range of 1000–3000 r min −1 with core/shell weight ratios of 3/1, 2/1, 1/1, 1/2 and 1/3, respectively. The shell of microPCMs was smooth and compact with global shape, its thickness was not greatly affected by the core/shell ratio and emulsion stirring rate. DSC tests showed that the shell of microPCMs did not influence the phase change behavior of pure paraffin. It was found from TGA analysis that microPCMs samples containing paraffin lost their weight at the temperature of nearly 250 °C, which indicated that the PCM had been protected by shell. More shell material in microPCMs could enhance the thermal stability and provide higher compact condition for core material. After a 100-times thermal cycling treatment, the microPCMs contain paraffin also nearly did not change the phase change behaviors of PCM. With the increasing of weight contents of microPCMs in gypsum board, the thermal conductivity (λ) values of composites had decreased. The simulation of temperature tests proved that the 16. Surface controlled dissolution rates of gypsum in aqueous solutions exhibit nonlinear dissolution kinetics Science.gov (United States) Jeschke, Alexander A.; Vosbeck, Katrin; Dreybrodt, Wolfgang 2001-01-01 The effective dissolution rates of gypsum are determined by mixed kinetics, where the rate constants of dissolution at the surface and the transport constant of molecular diffusion of dissolved material are similar. To obtain the surface reaction rate law it is necessary to know the transport constant. We have determined the surface rate law for monocrystalline selenite by using a rotating disc set-up, where the transport coefficients are well known. As a result, up to a calcium concentration of 0.6 · ceq, we find a nearly linear rate law Rs = ksl (1- cs/ ceq) n1, where cs is the total calcium concentration at the surface and ceq the equilibrium concentration with respect to gypsum, n1 = 1.2 ± 0.2, and ksl = 1.1 · 10 -4 mmol cm -2 s -1 ± 15%. We also employed batch-experiments for selenite, alabaster and gypsum rock samples. The result of these experiments were interpreted by using a transport constant determined by NaCl dissolution experiments under similar physical conditions. The batch experiments reveal a dissolution rate law Rs = ksl (1- cs/ ceq) n1, ksl = 1.3 · 10 -4 mmol · cm -2 s -1, n1 = 1.2 ± 0.2 for c ≤ 0.94 · ceq. Close to equilibrium a nonlinear rate law, Rs = ks2 (1- cs/ ceq) n2, is observed, where ks2 is in the order of 10 mmol · cm -2 s -1 and n2 ≈ 4.5. The experimentally observed gypsum dissolution rates from the batch experiments could be accurately fitted, with only minor variations of the surface reaction constant obtained from the rotating disk experiment and the transport coefficient from the NaCl dissolution batch experiment. Batch experiments on pure synthetic gypsum, reveal a linear rate law up to equilibrium. This indicates inhibition of dissolution in natural samples close to equilibrium, as is known also for calcite minerals. 17. The next chapter in experimental petrology: Metamorphic dehydration of polycrystalline gypsum captured in 3D microtomographic time series datasets Science.gov (United States) Bedford, John; Fusseis, Florian; Leclere, Henry; Wheeler, John; Faulkner, Dan 2016-04-01 Nucleation and growth of new minerals in response to disequilibrium is the most fundamental metamorphic process. However, our current kinetic models of metamorphic reactions are largely based on inference from fossil mineral assemblages, rather than from direct observation. The experimental investigation of metamorphism has also been limited, typically to concealed vessels that restrict the possibility of direct microstructural monitoring. Here we present one of the first time series datasets that captures a metamorphic reaction, dehydration of polycrystalline gypsum to form hemihydrate, in a series of three dimensional x-ray microtomographic datasets. We achieved this by installing an x-ray transparent hydrothermal cell (Fusseis et al., 2014, J. Synchrotron Rad. 21, 251-253) in the microtomography beamline 2BM at the Advanced Photon Source (USA). In the cell, we heated a millimetre-sized sample of Volterra Alabaster to 388 K while applying an effective pressure of 5 MPa. Using hard x-rays that penetrate the pressure vessel, we imaged the specimen 40 times while it reacted for approximately 10 hours. Each microtomographic dataset was acquired in 300 seconds without interrupting the reaction. Our absorption microtomographic data have a voxel size of 1.3 μm, which suffices to analyse the reaction progress in 4D. Gypsum can clearly be distinguished from hemihydrate and pores, which form due to the large negative solid volume change. On the resolved scale, the first hemihydrate needles appear after about 2 hours. Our data allow tracking of individual needles throughout the entire experiment. We quantified their growth rates by measuring their circumference. While individual grains grow at different rates, they all start slowly during the initial nucleation stage, then accelerate and grow steadily between about 200 and 400 minutes before reaction rate decelerates again. Hemihydrate needles are surrounded by porous haloes, which grow with the needles, link up and 18. Reforestation and landscape reconstruction in gypsum mine area from the semiarid region of NE Brazil Science.gov (United States) Bittar, S. M. B.; Straaten, P. V.; de Araujo Vieura Santos, M. de Fatima; Agra Bezerra da Silva, Y. J.; da Silva, M.; Saraiva de Melo Pinheiro, T.; Gusmao Didier de Moraes, F.; de Aguiar Accioly, A. M.; Alves de Santana, S. R.; dos Santos, H. A.; de Carvalho, D. M.; de Lima Ferreira, G.; de Carvalho Santos, C. 2012-04-01 In the Araripe region, Northeast Brazil, exist the world's second largest reserve of gypsum, estimated at over than one billion tons, which accounts for 95% of the Brazilian production and constitutes an important segment of the regional economy. The gypsum deposit occurs in the Lower Cretaceous Santana Formation of the Araripe basin, which is constituted by siltstones, marls, limestones, shales and gypsum layers. The ore extraction is from an open pit, on simple benches with a height of about 15 meters. Activities in mining operations involve stripping, drilling, loading explosives, blast, fragmentation and block loading / transport. Currently, gypsum mining and processing results in major changes in the landscape (pits and wastes heaps sedimentary rocks and soil mixture), deforestation of the "caatinga" ecosystem for use as firewood in small calcinations, dust pollution and changes in hydrology. To promote environmental remediation of this area, a multidisciplinary research has being done with the aim to support reforestation at the wastes heaps. The study involved the following activities: collection and physical, chemical and mineralogical characterization of mine waste materials; a floristic survey around the mines (botanical identification and measuring physical parameters in 16 plots, in order to identify which species are best suited to the conditions of the substrate at the mine site); an experiment (randomized block design) developed in a greenhouse, where seedlings of various native tree species were grown in a "constructed soil" made up of gypsum waste combined with chicken, goat and cattle manure, aimed to select tree species and soil treatment to be used in a waste heap; and an assessment of water quality for irrigation of the reforestation areas. The waste materials consist of large clayey aggregates, which may present physical/chemical properties unfavorable for plant development. The mineralogy of the sand fraction (> 85% quartz, gypsum and 19. Polymeric-SiO2-PCMs for improving the thermal properties of gypsum applied in energy efficient buildings International Nuclear Information System (INIS) Borreguero, Ana M.; Serrano, Angel; Garrido, Ignacio; Rodríguez, Juan F.; Carmona, Manuel 2014-01-01 Highlights: • Inorganic–organic PCM microcapsules were incorporated into gypsum. • The physical and thermal properties of the gypsum composites were studied. • The gypsum composites presented better properties than some previously investigated. • 10.20 kW h/operating cycle could be saved in a room with 1 m 3 of this material. • 1.26 kg of CO 2 emissions could be reduced per one operating cycle. - Abstract: A new thermoregulating material containing the commercial paraffin Rubitherm®RT27 stabilized by SiO 2 with a polymeric shell from polystyrene–divinylbenzene (Polymeric-SiO 2 -PCMs) was incorporated into gypsum up to a 15 mass ratio respect to the initial hemihydrate in order to develop building materials with a high thermal energy store (TES) capacity. The effect of this material on the gypsum crystals and the main physical, thermal and mechanical properties were studied and compared to those caused by another three kinds of thermoregulating materials. Polymeric-SiO 2 -PCMs presented the lowest agglomeration and therefore, the best distribution into the gypsum pores. As expected, the thermoregulating effect of the PCM improved the thermal properties of the gypsum since, the higher the microcapsules content, the higher the equivalent heat capacity (c p ) and the accumulated heat power (q acc ). Considering a conversion of 100% of the accumulated heat into electricity savings, the addition of a 15% of microcapsules respect to the hemihydrate allowed to save 10.20 kW h/m 3 and, consequently, reduced the CO 2 emissions in a 1.26 kg of CO 2 per operating cycle. Besides, the addition of the Polymeric-SiO 2 -PCMs reduces the gypsum density, but it is always higher than 600 kg/m 3 , as required by the European regulation EN 13279-2. The thermal conductivity (k) is also reduced by the microcapsules addition but for the case of a content of 15%. On the other hand, the porosity is barely affected just varying always less than a 3.5%. Finally, despite of the 20. Evaluation of potential for mercury volatilization from natural and FGD gypsum products using flux-chamber tests. Science.gov (United States) Shock, Scott S; Noggle, Jessica J; Bloom, Nicholas; Yost, Lisa J 2009-04-01 Synthetic gypsum produced by flue-gas desulfurization (FGD) in coal-fired power plants (FGD gypsum) is put to productive use in manufacturing wallboard. FGD gypsum wallboard is widely used, accounting for nearly 30% of wallboard sold in the United States. Mercury is captured in flue gas and thus is one of the trace metals present in FGD gypsum; raising questions about the potential for mercury exposure from wallboard. Mercury is also one of the trace metals present in "natural" mined gypsum used to make wall board. Data available in the literature were not adequate to assess whether mercury in wallboard from either FGD or natural gypsum could volatilize into indoor air. In this study, mercury volatilization was evaluated using small-scale (5 L) glass and Teflon flux chambers, with samples collected using both iodated carbon and gold-coated sand traps. Mercury flux measurements made using iodated carbon traps (n=6) were below the detection limit of 11.5 ng/m2-day for all natural and synthetic gypsum wallboard samples. Mercury flux measurements made using gold-coated sand traps (n=6) were 0.92 +/- 0.11 ng/m2-day for natural gypsum wallboard and 5.9 +/- 2.4 ng/m2-day for synthetic gypsum wallboard. Room air mercury concentrations between 0.028 and 0.28 ng/m3 and between 0.13 and 2.2 ng/m3 were estimated based on the flux-rate data for natural and synthetic gypsum wallboard samples, respectively, and were calculated assuming a 3 m x 4 m x 5 m room, and 10th and 90th percentile air exchange rates of 0.18/hour and 1.26/hour. The resulting concentration estimates are well below the U.S. Environmental Protection Agency (EPA) reference concentration for indoor air elemental mercury of 300 ng/m3 and the Agency for Toxic Substances and Disease Registry minimal risk level (MRL) of 200 ng/m3. Further, these estimates are below background mercury concentrations in indoor air and within or below the range of typical background mercury concentrations in outdoor air. 1. Optimization of the level and range of working temperature of the PCM in the gypsum-microencapsulated PCM thermal energy storage unit for summer conditions in Central Poland Science.gov (United States) Łapka, P.; Jaworski, M. 2017-10-01 In this paper thermal energy storage (TES) unit in a form of a ceiling panel made of gypsum-microencapsulated PCM composite with internal U-shaped channels was considered and optimal characteristics of the microencapsulated PCM were determined. This panel may be easily incorporated into, e.g., an office or residential ventilation system in order to reduce daily variations of air temperature during the summer without additional costs related to the consumption of energy for preparing air parameters to the desired level. For the purpose of the analysis of heat transfer in the panel, a novel numerical simulator was developed. The numerical model consists of two coupled parts, i.e., the 1D which deals with the air flowing through the U-shaped channel and the 3D which deals with heat transfer in the body of the panel. The computational tool was validated based on the experimental study performed on the special set-up. Using this tool an optimization of parameters of the gypsum-microencapsulated PCM composite was performed in order to determine its most appropriate properties for the application under study. The analyses were performed for averaged local summer conditions in Warsaw, Poland. 2. Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany Directory of Open Access Journals (Sweden) M. Hallenberger 2018-01-01 Full Text Available The Zechstein-2-Carbonates represent one of the most prolific hydrocarbon systems of Central Europe. Carbonate reservoir quality is primarily controlled by mineralogy, with dolomite representing moderate-to-good porosities and calcite commonly representing low porosities. Current models suggest that this calcite is the result of a basin-wide phase of dedolomitization. The calcium (Ca source for the dedolomites is thought to be derived from the fluids liberated during gypsum-to-anhydrite conversion. We present an easy-to-use and generally applicable template to estimate the dedolomitization potential of these fluids. Depending on reaction stoichiometry, salinity, and temperature, we estimate that between 2.8⁎10−3 m3 and 6.2⁎10−3 m3 of calcite may replace dolomite for each m3 of anhydrite created. Within the constraints dictated by the environment of the late Permian Zechstein basin, we estimate that about 5⁎10−3 m3 of dedolomite is created for each m3 of anhydrite. Mass balance constraints indicate that fluids derived from gypsum-to-anhydrite conversion account for less than 1% of the observed dedolomite in most of the studied industry wells from northern Germany. 3. Why does carbon increase in highly weathered soil under no-till upon lime and gypsum use? Science.gov (United States) Inagaki, Thiago Massao; de Moraes Sá, João Carlos; Caires, Eduardo Fávero; Gonçalves, Daniel Ruiz Potma 2017-12-01 Field experiments have been used to explain how soil organic carbon (SOC) dynamics is affected by lime and gypsum applications, however, how SOC storage occurs is still debatable. We hypothesized that although many studies conclude that Ca-based soil amendments such as lime and gypsum may lead to SOC depletion due to the enhancement of microbial activity, the same does not occur under conservation agriculture conditions. Thus, the objective of this study was to elucidate the effects of lime and gypsum applications on soil microbial activity and SOC stocks in a no-till field and in a laboratory incubation study simulating no-till conditions. The field experiment was established in 1998 in a clayey Oxisol in southern Brazil following a completely randomized blocks design with a split-plot arrangement and three replications. Lime and gypsum were surface applied in 1998 and reapplied in 2013. Undisturbed soil samples were collected before the treatments reapplications, and one year after. The incubation experiment was carried out during 16months using these samples adding crop residues on the soil surface to simulate no-till field conditions. Lime and gypsum applications significantly increased the labile SOC stocks, microbial activity and soil fertility attributes in both field and laboratory experiments. Although the microbial activity was increased, no depletion of SOC stocks was observed in both experiments. Positive correlations were observed between microbial activity increase and SOC gains. Labile SOC and Ca 2+ content increase leads to forming complex with mineral soil fractions. Gypsum applications performed a higher influence on labile SOC pools in the field than in the laboratory experiment, which may be related to the presence of active root system in the soil profile. We conclude that incubation experiments using lime and gypsum in undisturbed samples confirm that soil microbial activity increase does not deplete SOC stocks under conservation agriculture 4. Reduction of painful area as new possible therapeutic target in post-herpetic neuropathic pain treated with 5% lidocaine medicated plaster: a case series Directory of Open Access Journals (Sweden) Casale R 2014-06-01 Full Text Available Roberto Casale,1,2 Maria Di Matteo,3,7 Cristina E Minella,4,7 Guido Fanelli,5,7 Massimo Allegri4,6,71Department of Clinical Neurophysiology and Pain Rehabilitation Unit, Foundation Salvatore Maugeri, IRCCS, Pavia, 2EFIC Montescano School, Montescano, 3Anesthesia and Intensive Care I, 4Pain Therapy Service, Fondazione IRCCS Policlinico San Matteo, Pavia, 5Department of Anesthesia, Intensive Care and Pain Therapy, Azienda Ospedaliera Universitaria Parma, University of Parma, Parma, 6Department of Clinical, Surgical, Diagnostic and Pediatric Science, University of Pavia, Pavia, 7Study In Multidisciplinary Pain Research Group, Parma, ItalyAbstract: Post-herpetic neuralgia (PHN is neuropathic pain persisting after an acute episode of herpes zoster, and is associated with severe pain and sensory abnormalities that adversely affect the patient's quality of life and increase health care costs. Up to 83% of patients with PHN describe localized neuropathic pain, defined as “a type of neuropathic pain characterized by consistent and circumscribed area(s of maximum pain”. Topical treatments have been suggested as a first-line treatment for localized neuropathic pain. Use of 5% lidocaine medicated plaster could reduce abnormal nervous peripheral discharge and via the plaster could have a “protective” function in the affected area. It has been suggested that use of this plaster could reduce pain as well as the size of the painful area. To evaluate this possible outcome, we retrospectively reviewed eight patients with PHN, treated using 5% lidocaine medicated plaster. During a follow-up period of 3 months, we observed good pain relief, which was associated with a 46% reduction in size of the painful area after one month (from 236.38±140.34 cm2 to 128.80±95.7 cm2 and a 66% reduction after 3 months (81.38±59.19 cm2. Our study cohort was composed mainly of elderly patients taking multiple drugs to treat comorbidities, who have a high risk of drug 5. Fate of gypsum-sulphur applied to soybean on Typic haplustepts International Nuclear Information System (INIS) Saharan, Neelam; Rattan, R.K. 2004-01-01 Field experiments were conducted on the sulphur-deficient Typic Haplustepts of the IARI farm for two consecutive, kharif seasons viz. 1996 and 1997 with soybean cultivar Pusa 22 as the crop. Varying rates of S as gypsum were basally applied in the main plots adjacent to the micro plots (1 m x 1 m) to quantify the partitioning of the fertilizer-sulphur taken up by soybean and its distribution in the soil profile. Soybean responded to the application of sulphur, with increase in yield being obtained up to rate of 40 kg S ha -1 . Data computed on distribution of the S derived from labelled gypsum and percent S utilization by the soybean crop increased from 13.23 and 4.15 to 23.41 and 6.39, respectively. During 1996, the per cent utilization of labelled S ranged from 5.6 to 8.8. Monitoring of added sulphur in the soil profile up to a depth of 1 m revealed maximum accumulation of the added S in 30-60 cm soil layer. With the help of 35 S around 11 to 18 per cent of the added S was traced in 60-100 cm soil layer. It can be concluded from the data for two years that during kharif season the application of S through water soluble sources like ammonium sulphate and ammonium phosphate sulphate should be avoided because even S from the sparingly soluble gypsum migrated to a depth of 1 m during the cropping season. (author) 6. High Levels of Antibiotic Resistance but No Antibiotic Production Detected Along a Gypsum Gradient in Great Onyx Cave, KY, USA Directory of Open Access Journals (Sweden) Kathleen Lavoie 2017-09-01 Full Text Available A preliminary study of antibiotic production and antibiotic resistance was conducted in Great Onyx Cave in Mammoth Cave National Park, KY, to determine if gypsum (CaSO4∙2H2O affects these bacterial activities. The cave crosses through the width of Flint Ridge, and passages under the sandstone caprock are dry with different amounts of gypsum. The Great Kentucky Desert hypothesis posits that gypsum limits the distribution of invertebrates in the central areas of Great Onyx Cave. Twenty-four bacterial isolates were cultivated from swabs and soils. Using three methods (soil crumb, soil crumb with indicator bacteria, and the cross-streak method using isolated bacteria we did not detect any production of antibiotics. Antibiotic resistance was widespread, with all 24 isolates resistant to a minimum of two antibiotics of seven tested, with three isolates resistant to all. Antibiotic resistance was high and not correlated with depth into the cave or the amount of gypsum. The Great Kentucky Desert hypothesis of the negative effects of gypsum seems to have no impact on bacterial activity. 7. The impact of gypsum mine water: A case study on morphology and DNA integrity in the freshwater invertebrate, Gammarus balcanicus International Nuclear Information System (INIS) Ternjej, Ivančica; Mihaljević, Zlatko; Ivković, Marija; Previšić, Ana; Stanković, Igor; Maldini, Krešimir; Želježić, Davor; Kopjar, Nevenka 2014-01-01 The aim of our study was to investigate how exposure to heavy metal-rich waters from gypsum mining affects the morphology and levels of primary DNA damage in Gammarus balcanicus. Chemical analysis revealed increased concentrations of metals in water and sediment collected at a site impacted by gypsum mine wastewaters. The specimens also showed elevated total tissue metal levels when compared with the organisms collected at the reference site. The most prominent increase was observed for strontium, followed by iron, nickel, vanadium, aluminium, and manganese. The major pathway of entry for these toxic substances was through the degraded exoskeleton as a consequence of excessive strontium input (unbalanced calcium/strontium ratio) and altered permeability. Disturbed exoskeleton integrity was observed only in individuals collected downstream of the gypsum mine, which was confirmed by electron microscopy. Levels of primary DNA damage were evaluated using the alkaline comet assay in the haemolymph of the specimens. - Highlights: • Our findings suggest toxic potential of gypsum mine wastewaters. • The Gammarus specimens showed elevated total tissue metal levels. • Strontium uptake disturbed exoskeleton integrity. • Corrupted cuticle altered permeability to other toxic substances. • Combined effects of all contaminants caused genotoxicity. - Gypsum mine wastewaters have genotoxic potential and affect the gammarid exoskeleton morphology and biochemistry associated with a high strontium uptake 8. Climatic control on the growth of gigantic gypsum crystals within hypogenic caves (Naica mine, Mexico)? Science.gov (United States) Garofalo, Paolo S.; Fricker, Mattias B.; Günther, Detlef; Forti, Paolo; Mercuri, Anna-Maria; Loreti, Mara; Capaccioni, Bruno 2010-01-01 Three hypogenic caves within the Naica mine of Mexico ( Cueva de los Cristales — CLC, Ojo de la Reina — OR, and Cueva de las Velas — CLV) host spectacular gypsum crystals up to 11 m in length. These caves are close to another shallow cave of the area ( Cueva de las Espadas — CLE), with which they cover a 160 m-deep vertical section of the local drainage basin. Similar to other hypogenic caves, all these caves lack a direct connection with the land surface and should be unrelated with climate. A record of multi-technique fluid inclusion data and pollen spectra from cave and mine gypsum indicates surprisingly that climatic changes occurring at Naica could have controlled fluid composition in these caves, and hence crystal growth. Microthermometry and LA-ICP-Mass Spectrometry of fluid inclusions indicate that the shallow, chemically peculiar, saline fluid (up to 7.7 eq. wt.%NaCl) of CLE could have formed from evaporation, during a dry and hot climatic period. The fluid of the deep caves was instead of low salinity (˜ 3.5 eq. wt.% NaCl) and chemically homogeneous, and was poorly affected by evaporation. We propose that mixing of these two fluids, generated at different depths of the Naica drainage basin, determined the stable supersaturation conditions for the gigantic gypsum crystals to grow. Fluid mixing was controlled by the hydraulic communication between CLE and the other deep caves, and must have taken place during cycles of warm-dry and fresh-wet climatic periods, which are known to have occurred in the region. Pollen grains from a 35 ka-old gypsum crystal of CLC corresponds to a fairly homogenous catchment basin made of a mixed broadleaf wet forest, which suggests precipitation during a fresh-wet climatic period and confirms our interpretation of the fluid inclusion data. The unusual combination of geological and geochemical factors of Naica suggests that other hypogenic caves found elsewhere may not host similar crystals. However, this work shows that 9. In situ characterization of ancient plaster and pigments on tomb walls in Egypt using energy dispersive X-ray diffraction and fluorescence International Nuclear Information System (INIS) Uda, M. 2004-01-01 A portable type of energy dispersive X-ray diffraction and fluorescence (ED-XRDF) spectrometer was developed, whose operation mode is completely different from that of an X-ray diffractometer commercially available. The former is operated in energy dispersive mode but the latter in angle dispersive mode. The performance of the ED-XRDF spectrometer was tested in the field, i.e. in the tomb of Amenhotep III, built in 1364 B.C. or earlier in Egypt. The crystal structure and chemical composition of ancient plaster and pigments were successfully determined in the field using the spectrometer. The same areas investigated by the ED-XRDF spectrometer were also examined with an optical microscope. The plaster is found to be composed of anhydrite, calcite and quartz. White and yellow pigments were identified as huntite and orpiment, respectively. Egyptian blue and goethite were found in the green colored parts 10. Reinforced plaster by means of the synergic action between concrete additives (superfluidifiers, fluidiflers and airing-plasticizers and E glass fibres Directory of Open Access Journals (Sweden) del Río Merino, M. 2000-12-01 Full Text Available Through the analysis of the different compounds (plaster + additives + E glass fibres we pretend to demostrate that a synergic action is present between certain concrete additives (superfluidifiers, fluidiflers, and airingplasticizers and E glass fibre, on the basis of the flection resistance of plaster matrix based compound materials. Mediante el análisis de diferentes compuestos (escayola + aditivos + fibras de vidrio E se pretende demostrar que existe una acción sinérgica entre ciertos aditivos del hormigón (superfluidificantes, fluidificantes y aireantes-plastificantes y los refuerzos a base de fibras de vidrio E, sobre la resistencia a flexión de los materiales compuestos de matriz principal escayola. 11. Lead, cadmium, and zinc concentrations in plaster and mortar from structures in Jasper and Newton Counties, Missouri (Tri-State Mining District) Energy Technology Data Exchange (ETDEWEB) Perry, Phyllis M [Chemistry Department, Southwest Missouri State University, 901 S. National Avenue, Springfield, MO 65804 (United States); Pavlik, Jeffrey W [Chemistry Department, Southwest Missouri State University, 901 S. National Avenue, Springfield, MO 65804 (United States); Sheets, Ralph W [Chemistry Department, Southwest Missouri State University, 901 S. National Avenue, Springfield, MO 65804 (United States); Biagioni, Richard N [Chemistry Department, Southwest Missouri State University, 901 S. National Avenue, Springfield, MO 65804 (United States) 2005-01-05 The primary goal of this study was to evaluate anecdotal evidence that within Jasper and Newton Counties, Missouri, two counties within the Tri-State Mining District, granular mine tailings were commonly used in place of river sands in wall plasters and mortar. Interior wall plaster and mortar samples from structures in this mining district were analyzed for lead, cadmium, and zinc, and compared to samples from Springfield, MO (comparison site). The Jasper and Newton County samples showed elevated concentrations of the three elements, consistent with the inclusion of mine tailings, with a number of samples containing lead and cadmium at concentrations greater than EPA remediation targets for yard soil. X-ray diffraction studies showed the presence of the zinc ore minerals, sphalerite and hemimorphite, in high level samples. Thin section optical studies identified the major component of the aggregate as chert, a mineral abundant within the tailing piles. Because dust from crumbling plaster and mortar could represent an avenue for significant heavy metal exposure to building occupants, we suggest that there may be associated health consequences that should be further evaluated. 12. Lead, cadmium, and zinc concentrations in plaster and mortar from structures in Jasper and Newton Counties, Missouri (Tri-State Mining District) International Nuclear Information System (INIS) Perry, Phyllis M.; Pavlik, Jeffrey W.; Sheets, Ralph W.; Biagioni, Richard N. 2005-01-01 The primary goal of this study was to evaluate anecdotal evidence that within Jasper and Newton Counties, Missouri, two counties within the Tri-State Mining District, granular mine tailings were commonly used in place of river sands in wall plasters and mortar. Interior wall plaster and mortar samples from structures in this mining district were analyzed for lead, cadmium, and zinc, and compared to samples from Springfield, MO (comparison site). The Jasper and Newton County samples showed elevated concentrations of the three elements, consistent with the inclusion of mine tailings, with a number of samples containing lead and cadmium at concentrations greater than EPA remediation targets for yard soil. X-ray diffraction studies showed the presence of the zinc ore minerals, sphalerite and hemimorphite, in high level samples. Thin section optical studies identified the major component of the aggregate as chert, a mineral abundant within the tailing piles. Because dust from crumbling plaster and mortar could represent an avenue for significant heavy metal exposure to building occupants, we suggest that there may be associated health consequences that should be further evaluated 13. Determination of Ra-226 and Th-232 in samples of natural phosphates, industrial gypsums and surface soils by gamma spectrometry International Nuclear Information System (INIS) Pessenda, L.C.R.; Nascimento Filho, V.F. do; Nadai, E.A. de; Barros Ferraz, E.S. de; Sao Paulo Univ., Piracicaba 1988-01-01 The natural radioactivity in Ra-226 and Th-232 in samples of natural phosphates, industrial gypsums (phosphogypsums) and surface soils of different regions was measured by γ-ray spectrometry. The majority of phosphates and gypsums examined showed significantly higher values than soils, mainly in relation to Ra-226 activity. The activity ranges found for phosphates, gypsums and soils were: 79.1 - 3180 Bq/kg, 56.3 - 986.6 Bq/kg, 8.8 - 54.3 Bq/kg for Ra-226 and 33.6 - 1450.3 Bq/kg; 17.4 - 130,1 Bq/kg, 9.8 - 108.9 Bq/kg for Th-232, respectively. (author) [pt 14. An analysis of the persistent presence of opportunistic pathogens on patient-derived dental impressions and gypsum casts. Science.gov (United States) Egusa, Hiroshi; Watamoto, Takao; Abe, Keike; Kobayashi, Munemasa; Kaneda, Yoshitoshi; Ashida, Shunji; Matsumoto, Takuya; Yatani, Hirofumi 2008-01-01 This study aimed to assess the persistent presence of microorganisms on patient-derived dental impressions and gypsum casts, while highlighting important human pathogens such as Candida, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. The practices and opinions regarding cross-infection control from 59 general dentists in Japan were obtained via a questionnaire. Alginate impressions were made from 56 patients. Using a brain heart infusion agar medium, impression and imprint cultures were carried out to visualize the microbial contamination on the surfaces of the impressions and gypsum casts, respectively. The colonies on the surfaces of the 30 impression cultures and 26 imprint cultures were collected by swabbing and then inoculated onto selective agar plates to detect streptococci, staphylococci, Candida, MRSA, and P aeruginosa. The questionnaire showed that only 54% of general dentists had a cross-infection policy in their dental clinics, and only 30% to 40% were aware of the possible persistence of MRSA or P aeruginosa on impressions and gypsum casts. The impression/imprint cultures grew a large number of visible bacterial colonies on all of impression/gypsum cast samples investigated. Selective agar cultures demonstrated the presence of streptococci (100, 100%), staphylococci (56.7, 65.4%), Candida (30, 46.2%), MRSA (26.7, 15.4%), and P aeruginosa (6.7, 7.7%) on the impressions and the gypsum casts, respectively. This investigation showed that patient-derived dental impressions and gypsum casts are contaminated with numerous microbes, including Candida, MRSA, and P aeruginosa, which are known pathogens responsible for nosocomial and/or life-threatening infection in the immunocompromised host. 15. Leaching characteristics of trace elements in desulfurization gypsum from a coal-fired power plant Energy Technology Data Exchange (ETDEWEB) Liu, Y.K.; Zhuo, Y.Q.; Zhu, Z.W.; Chen, C.H. [Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering 2013-07-01 The contents and leaching characteristics of Cr, Cd, As, Pb and Se in FGD gypsum from a 200 MW coal-fired power plant were investigated in this study. Experimental results revealed that: the leaching characteristics of As and Se were similar, both leaching rates were not obviously affected by pH but increased with increase of the liquid-solid ratio. Pb and Cr had similar leaching characteristics, their leaching rates were closely related with the pH of leaching solution and increased with the lowering of pH and both increased with the increasing of solid-liquid ratio. Along with the increase of the liquid-solid ratio, the leaching gradually achieved balance, and the balanced liquid-solid ratio was bigger when pH of leaching solution was lower. Cd content of leaching solution was below detect limit, and thus failed to get its leaching characteristics. The order of trace element content in leaching solution is Pb < Cr < As < Se, and the order of leaching rates is Cr < As < Pb < Se. BCR extraction procedure revealed that trace elements in FGD gypsum were mainly existed as available fraction and migration ability was stronger than that of trace elements in fly ash from coal-fired power plants. 16. The production of hydroxyapatite prototypes from solid bodies of Gypsum/Polyvinyl Alcohol composites Energy Technology Data Exchange (ETDEWEB) Barbosa, Amanda Alves; Ferraz, Andrea de Vasconcelos; Dantas, Alan Christie; Olivier, Nelson Cardenas, E-mail: [email protected] [Universidade Federal do Vale do Sao Francisco (UNIVASF), Juazeiro, BA (Brazil) 2014-08-15 Prototypes of porous hydroxyapatite (HAp) were produced from Gypsum/PVA composite, using a mass proportion of 15% polymer. The material was obtained by means of chemical conversion in (NH{sub 4}){sub 2}HPO{sub 4} 0.5 mol.L{sup -1} solution and NH{sub 4}OH 6.0 mol.L{sup -1} alkaline medium for pH control, maintained between 6.0 and 9.0. The reaction occurred at a temperature of 100°C at different test times. The obtained HAp was characterized by several techniques, such as FTIR, which identified the SO{sub 4}{sup 2-} groups characteristic for the Gypsum block, and the PO{sub 4}{sup 2-} groups that are attributed to the biomaterial HAp, besides XRD and SEM, which made it possible to confirm a successful conversion of the material. Tests for mechanical resistance to compression (σ{sub c}) were carried out for both materials as well. (author) 17. Potential Agricultural Uses of Flue Gas Desulfurization Gypsum in the Northern Great Plains Energy Technology Data Exchange (ETDEWEB) DeSutter, T.M.; Cihacek, L.J. [North Dakota State University, Fargo, ND (United States). Department of Soil Science 2009-07-15 Flue gas desulfurization gypsum (FGDG) is a byproduct from the combustion of coal for electrical energy production. Currently, FGDG is being produced by 15 electrical generating stations in Alabama, Florida, Indiana, Iowa, Kentucky, Ohio, North Carolina, South Carolina, Tennessee, Texas, and Wisconsin. Much of this byproduct is used in the manufacturing of wallboard. The National Network for Use of FGDG in Agriculture was initiated to explore alternative uses of this byproduct. In the northern Great Plains (North Dakota, South Dakota, and Montana), FGDG has the potential to be used as a Ca or S fertilizer, as an acid soil ameliorant, and for reclaiming or mitigating sodium-affected soils. Greater than 1.4 million Mg of FGDG could initially be used in these states for these purposes. Flue gas desulfurization gypsum can be an agriculturally important resource for helping to increase the usefulness of problem soils and to increase crop and rangeland production. Conducting beneficial use audits would increase the public awareness of this product and help identify to coal combustion electrical generating stations the agriculturally beneficial outlets for this byproduct. 18. Regional transport of a chemically distinctive dust: Gypsum from White Sands, New Mexico (USA) Science.gov (United States) White, Warren H.; Hyslop, Nicole P.; Trzepla, Krystyna; Yatkin, Sinan; Rarig, Randy S.; Gill, Thomas E.; Jin, Lixin 2015-03-01 The White Sands complex, a National Monument and adjoining Missile Range in southern New Mexico, occupies the dry bed of an ice-age lake where an active gypsum dunefield abuts erodible playa sediments. Aerosols entrained from White Sands are sometimes visible on satellite images as distinct, light-colored plumes crossing the Sacramento Mountains to the east and northeast. The IMPROVE network (Interagency Monitoring of PROtected Visual Environments) operates long-term aerosol samplers at two sites east of the Sacramento range. In recent years a spring pulse of sulfate aerosol has appeared at these sites, eclipsing the regional summer peak resulting from atmospheric reactions of sulfur dioxide emissions. A significant fraction of this spring sulfate is contributed by gypsum and other salts from White Sands, with much of the sulfur in coarse particles and concentrations of calcium and strontium above regional levels. The increase in these gypsiferous species coincides with a drought following a period of above-average precipitation. White Sands and the IMPROVE samplers together provide a natural laboratory: a climatically sensitive dust source that is both well characterized and chemically distinct from its surroundings, with a signature that remains identifiable at long-term observatories 100-200 km downwind. 19. Late-stage anhydrite-gypsum-siderite-dolomite-calcite assemblages record the transition from a deep to a shallow hydrothermal system in the Schwarzwald mining district, SW Germany Science.gov (United States) Burisch, Mathias; Walter, Benjamin F.; Gerdes, Axel; Lanz, Maximilian; Markl, Gregor 2018-02-01 The majority of hydrothermal vein systems of economic interest occur at relatively shallow crustal levels, although many of them formed at significantly greater depths. Their present position is a consequence of uplift and erosion. Although, many aspects of their formation are well constrained, the temporal chemical evolution of such systems during uplift and erosion is still poorly understood. These vein minerals comprise calcite, dolomite-ankerite, siderite-magnesite, anhydrite and gypsum forming the last gangue assemblages in Jurassic and Tertiary sulphide-fluorite-quartz-barite veins of the Schwarzwald mining district, SW Germany. Mineral textures of samples from nine localities reveal that in these sequences, mineral precipitation follows a recurring pattern: early calcite is followed by anhydrite or gypsum, siderite and/or dolomite. This succession may repeat up to three times. In-situ (LA-ICP-MS) U-Pb age dating of 15 carbonates from three subsequent generations of the late-stage vein assemblage yield robust ages between 20 and 0.6 Ma. Each mineral sequence forms in a distinctive period of about 2-5 Ma. These ages clearly relate these late-stage mineral phases to the youngest geological episode of the Schwarzwald, which is associated with the Cenozoic Rhine Graben rifting and basement uplift. Based on thermodynamic modelling, the formation of the observed mineral assemblages required an deeply sourced Mg-, Fe- and SO4-rich fluid (b), which was episodically mixed with a shallow crustal HCO3-rich fluid (a). As a consequence of fluid mixing, concentrations of Mg, Fe and SO4 temporarily increased and initiated the formation of the observed sulphate-carbonate mineral sequences. This discontinuous large-scale vertical fluid mixing was presumably directly related to episodes of active tectonics associated with the Cenozoic strike-slip regime of the Upper Rhine Graben. Analogously, episodic fluid mixing is a major key in the formation of older (Jurassic to early 20. Lipid and Phylogenetic Analysis of a Gypsum-hosted Endoevaporitic Microbial Community Science.gov (United States) Turk, K. A.; Jahnke, L. L.; Green, S. J.; Kubo, M. D.; Vogel, M. B.; Des Marais, D. J. 2007-12-01 Gypsum evaporites host diverse, productive and volumetrically significant microbial communities and are relevant modern-day analogs to both Precambrian sabkha deposits and, potentially, Martian evaporites. Extensive evaporites form in subaqueous environments of high salinity ponds (>150 permil) maintained by the Exportadora de Sal, S. A. (ESSA) in Guerrero Negro, B.C.S., Mexico. A gypsarenite (reworked clastic gypsum) crust found along the southeast margin of ESSA's Pond 9 was collected in February 2004 and each vibrantly colored layer in the top centimeter was sampled. Extant microbial communities from each layer were characterized using complementary culture-independent molecular techniques, lipid biomarker analysis, and compound specific isotopic analysis. Coupling molecular analysis with lipid biomarker analysis revealed that oxygenic photosynthetic organisms dominate the surface layers (top 3 mm). Polar lipids from the surface layers consisted predominantly of glycolipids, which are characteristic of algae, cyanobacteria and green anoxygenic photosynthetic bacteria. Consistent with prior analyses of gypsum evaporites, 16S rRNA gene clone libraries indicate that cyanobacterial populations belong primarily to the genus Cyanothece. The bacterial community below the surface layers is more diverse and dominated by anaerobic organisms. Phototrophic purple sulfur bacteria, sulfate-reducing bacteria (SRB), and Bacteroidetes were particularly abundant. The relative abundances of SRB increased with depth; Desulfobacteraceae clones were distributed throughout the crust, but not at the surface, while Desulfovibrionaceae clones were found predominantly in the deepest layers. These molecular results are consistent with fatty acid biomarker analysis. δ13C values of major lipid classes in the crust and sediment range from 14 to 36‰, which is considerably lower than corresponding values for benthic Microcoleus-dominated cyanobacterial mats found at lower salinities at ESSA 1. Solar distiller of pyramidal covering and isolation in composite material the Plaster base and EPS; Destilador solar de cobertura piramidal e isolamento em material composito a base de Gesso e EPS Energy Technology Data Exchange (ETDEWEB) Santos, R. D.; Ribeiro, F. A.; Mendes, J. U.; Lima, R. S.; Souza, L. G.; Abreu, R. F. 2008-07-01 To demonstrate then term viability calorific and economic of the material, compared to the others conventional distiller, here is presented a solar distiller os simple stage, with has as main differential characteristics the geometry of the covering and the material used to make its coating. the model built has an area of 0,25 m{sup 2} and pyramidal covering, witch allows the collection of the distillate water in the four faces, different of just two like is found in the conventional distiller, besides promote the absorption of the radiation because of its versatility about the positioning of the sun. Not despite, its built is favored for the low cost associated and the agility in the process because it is made with a mix of gypsum, EPS ground and water, witch also attributes to the distiller thermal properties more favorable to the process of distillation. (Author) 2. The Long-Term Safety of S-Flurbiprofen Plaster for Osteoarthritis Patients: An Open-Label, 52-Week Study. Science.gov (United States) Yataba, Ikuko; Otsuka, Noboru; Matsushita, Isao; Matsumoto, Hideo; Hoshino, Yuichi 2016-08-01 The newly developed S-flurbiprofen plaster (SFPP) is a tape-type patch that shows innovative percutaneous absorption. This study was designed to evaluate the safety of a long-term 52-week SFPP application to osteoarthritis (OA) patients. This was a multi-center, open-label, uncontrolled prospective study that included 201 OA patients. SFPP at 40 mg/day was applied to the site of pain in 101 patients and at 80 mg/day (2 patches) in 100 patients at a total of 301 sites for 52 weeks. The affected sites assessed included the knee (192), lumbar spine (66), cervical spine (26), and others (17). Drug safety was evaluated by medical examination, laboratory tests, and examination of vital signs. Efficacy was evaluated by the patient's and clinician's global assessments and clinical symptoms. Most patients (80.1 %) completed the 52-week SFPP application. The majority of drug-related adverse events (AEs) included mild dermatitis at the application sites and occurred in 46.8 % of the sites. No photosensitive dermatitis was observed. Systemic AEs occurred in 9.0 % of the patients; a serious AE (gastric ulcer hemorrhage) occurred in one patient. No clinically significant changes in the laboratory tests and vital signs were observed. The efficacy evaluation showed an improvement from 2 weeks after the SFPP application, which continued during the 52 weeks' treatment. No apparent safety concerns were observed, even during the long-term SFPP application. Therefore, SFPP could be an additional pharmacotherapy in OA treatment. 3. High-yield synthesis of vaterite microparticles in gypsum suspension system via ultrasonic probe vibration/magnetic stirring Science.gov (United States) Wang, Bo; Pan, Zihe; Cheng, Huaigang; Chen, Zuliang; Cheng, Fangqin 2018-06-01 Vaterite-type calcium carbonate particles have some unique properties such as high hydrophilicity, large surface areas, and hierarchical structures consisting of primary vaterite particles in comparison with calcite or aragonite-type polymorphs. In this paper, gypsum (CaSO4·2H2O) suspension is used to synthesize micro-sized vaterite CaCO3 through magnetic stirring (MS) and ultrasonic probe vibration (UPV) methods. The effects of ammonia concentration, CO2 flow rate, solid-liquid ratio on the gypsum carbonation process, mineral phase composition, morphology and particle size distribution of CaCO3 are investigated. The results show that the carbonation process is significantly influenced by ammonia concentration, CO2 flow rate and ultrasound. Comparing with magnetic stirring, ultrasonic probe vibration take less time to reach the complete carbonate reaction. Gypsum is transformed to vaterite with the conversion rate about ∼95% when the mole ratio of NH4+/Ca2+ is 2.4 otherwise the carbonation reaction was uncompleted with gypsum residues left. Comparing with MS method, the UPV method resulted in smaller size and narrower size distribution of as-prepared microparticles and approximately 80% reduction of the particle size was achieved. It is established that increasing the solid-liquid ratio resulted in larger particle size in MS system and smaller particle size in UPV system. Increasing CO2 flow rate caused the particle size decreased in MS system and increased in UPV system. 4. Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture Science.gov (United States) The interest in using Flue Gas Desulfurization Gypsum(FGDG) has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using rece... 5. Metals in soil and runoff from a piedmont hayfield amended with broiler litter and flue gas desulfurization gypsum Science.gov (United States) Flue gas desulfurization gypsum (FGDG) from coal-fired power plants is available for agricultural use in many US regions. Broiler litter (BL) provides plant available N, P, and K but may be a source of unwanted arsenic (As), copper (Cu), and zinc (Zn). FGDG provides Ca and S and can reduce runoff lo... 6. Influence of gypsum on efflorescence in ceramic tiles; Influence da gipsita no surgimento de eflorescencia em telhas ceramicas Energy Technology Data Exchange (ETDEWEB) Monteiro, C.M.O.L. [Servico Nacional de Aprendizagem Industrial (SENAI), Teresina, PI (Brazil); Nascimento, R.M.; Martinelli, A.E. [Universidade Federal do Rio Grande do Norte (PPgCEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais 2009-07-01 The red ceramic industry is recognized as of major importance in Piaui State. The State capital, Teresina, is the greatest producer of this material, which is used mainly for masonry sealing blocks. One of the most frequent problems in this kind of products is the efflorescence.This paper has the main objective of studying the influence of gypsum on tiles, using the local industry production standards. The raw materials were characterized by FRX, DRX, thermal analysis and sulfates. Extruded test specimens were made with the addition of 1%, 3% and 5% of gypsum in the ceramic paste, burned at 850 deg C, 950 deg C and 1050 deg C and submitted to further technological and analysis for MEV. The reference ceramic paste did not show tendency to efflorescence formation after burning for samples with 1% gypsum added to the paste. The reference ceramic paste showed tendency to efflorescence formation after drying and consolidated efflorescence after burning for samples with 5% gypsum added to the paste. (author) 7. Gypsum (CaSO42H2O) scaling on polybenzimidazole and cellulose acetate hollow fiber membranes under forward osmosis KAUST Repository Chen, Si Cong 2013-11-08 We have examined the gypsum (CaSO42H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42 14.85 after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. 2013 by the authors; licensee MDPI, Basel, Switzerland. 8. [The reliability of dento-maxillary models created by cone-beam CT and rapid prototyping:a comparative study]. Science.gov (United States) Lv, Yan; Yan, Bin; Wang, Lin; Lou, Dong-hua 2012-04-01 To analyze the reliability of the dento-maxillary models created by cone-beam CT and rapid prototyping (RP). Plaster models were obtained from 20 orthodontic patients who had been scanned by cone-beam CT and 3-D models were formed after the calculation and reconstruction of software. Then, computerized composite models (RP models) were produced by rapid prototyping technique. The crown widths, dental arch widths and dental arch lengths on each plaster model, 3-D model and RP model were measured, followed by statistical analysis with SPSS17.0 software package. For crown widths, dental arch lengths and crowding, there were significant differences(Pmodels, but the dental arch widths were on the contrary. Measurements on 3-D models were significantly smaller than those on other two models(Pmodels, RP models had more numbers which were not significantly different from those on plaster models(P>0.05). The regression coefficient among three models were significantly different(Pmodels was bigger than that between 3-D and plaster models. There is high consistency within 3 models, while some differences were accepted in clinic. Therefore, it is possible to substitute 3-D and RP models for plaster models in order to save storage space and improve efficiency. 9. Age and speleogenesis of epigenic gypsum caves in the northern Apennines (Italy) Science.gov (United States) Columbu, Andrea; Chiarini, Veronica; De Waele, Jo; Drysdale, Russell; Forti, Paolo; Hellstrom, John; Woodhead, Jon 2016-04-01 Triassic and Messinian gypsum beds host the majority of the caves in the eastern flank of the northern Apennines. To date, more than six hundreds voids have been mapped, including the longest known epigenic gypsum cave system in the world (Spipola-Acquafredda, ~11 km of tunnels) (De Waele et al., 2013). Superimposed caves are typically sub-horizontal (Klimchouk, 2000) and connected through vertical shafts, reflecting the palaeo base-level variations. When preserved, river terraces at the surface lie at the same palaeo altitude of the base level and horizontal cave passages. Notwithstanding the well-known geology of the area known (Vai and Martini, 2001), the age of these caves has been greatly underestimated in the past. Considering the rapid dissolution of the gypsum and uplifting of the area, the start of speleogenesis activity was considered to have occurred during the last glacial age. The age of karst voids can be only indirectly estimated by the dating of the infilling sediments. U-Th dating on carbonate speleothems provides high-precision and accurate ages (Hellstrom, 2003; Scholz and Hoffmann, 2008). We thus applied this methodology to 20 speleothems coming from 14 different caves belonging to the Monte Tondo, Spipola Acquafredda, Castelnuovo, Stella-Rio Basino and Brisighella systems. The results show that: i) caves were forming since at least ~300 ka; ii) the peak of speleogenesis was reached during relatively cold climate stages, when rivers formed terraces at the surface and aggradation caused paragenesis in the stable cave levels (Columbu et al., 2015). Besides the significant contribution to the understanding of the Apennines evaporite karst evolution, this study (and its further advancement) may also refine knowledge of the local vs regional uplifting rates and base-level variations since the late Pleistocene (Wegmann and Pazzaglia, 2009). References Columbu, A., De Waele, J., Forti, P., Montagna, P., Picotti, V., Pons-Branchu, E., Hellstrom, J 10. Application of reject of gypsum from Trindade/PE in ceramic masses formulations International Nuclear Information System (INIS) Lima, Thalles Confessor de; Souza, Marcondes Mendes de; Almeida, Ana Beatriz Dantas de; Farias, Debora Santos Umbelino de; Nobrega, Luiz Felipe Pereira de Medeiros; Mendes, Luciana Bezerra 2016-01-01 The mining industry is a major producer of waste is to be harmful to the environment besides not being made possible for use in producing means, since the product of economic interest has been extracted. In order to reduce this problem, this work shows the characterization of the waste generated by gypsum mining in Trindade/PE in the ceramic coating. The residue was collected, ground and sieved to #200, then was chemically characterized by XRF analysis process, to evaluate its potential to be incorporated into the formulation of ceramic material, the material studied can be used in porcelain tile formulation as a flux element for that were obtained in the laboratory ceramic bodies adding the residue then were performed physical testing of linear shrinkage, water absorption and flexural breaking strain technically order to evaluate the addition of this residue ceramic coating. (author) 11. Effect of disinfection on irreversible hydrocolloid and alternative impression materials and the resultant gypsum casts. Science.gov (United States) Suprono, Montry S; Kattadiyil, Mathew T; Goodacre, Charles J; Winer, Myron S 2012-10-01 Many new products have been introduced and marketed as alternatives to traditional irreversible hydrocolloid materials. These alternative materials have the same structural formula as addition reaction silicone, also known as vinyl polysiloxane (VPS), impression materials. Currently, there is limited in vitro and in vivo research on these products, including on the effects of chemical disinfectants on the materials. The purpose of this study was to compare the effects of a spray disinfecting technique on a traditional irreversible hydrocolloid and 3 new alternative impression materials in vitro. The tests were performed in accordance with the American National Standards Institute/American Dental Association (ANSI/ADA) Specification Nos. 18 and 19. Under standardized conditions, 100 impressions were made of a ruled test block with an irreversible hydrocolloid and 3 alternative impression materials. Nondisinfected irreversible hydrocolloid was used as the control. The impressions were examined for surface detail reproduction before and after disinfection with a chloramine-T product. Type III and Type V dental stone casts were evaluated for linear dimensional change and gypsum compatibility. Comparisons of linear dimensional change were analyzed with 2-way ANOVA of mean ranks with the Scheffé post hoc comparisons (α=.05). Data for surface detail reproduction were analyzed with the Wilcoxon Signed-Rank procedure and gypsum compatibility with the Kruskal-Wallis Rank procedure (α=.05). The alternative impression materials demonstrated significantly better outcomes with all 3 parameters tested. Disinfection with chloroamine-T did not have any effect on the 3 alternative impression materials. The irreversible hydrocolloid groups produced the most variability in the measurements of linear dimensional change. All of the tested materials were within the ADA's acceptable limit of 1.0% for linear dimensional change, except for the disinfected irreversible hydrocolloid 12. Effect Of Coir Fibres On The Compaction And Unconfined Compressive Strength Of Bentonite-Lime-Gypsum Mixture Directory of Open Access Journals (Sweden) Tilak B. Vidya 2015-06-01 Full Text Available This paper presents the effect of coir fibres on the compaction and unconfined compressive strength of a bentonite-lime-gypsum mixture. The coir fiber content varied from 0.5 to 2 %. The results indicated that the dry unit weight and the optimum moisture content of a bentonite – lime mix increased with the addition of gypsum. The unconfined compressive strength of the bentonite increased with the increase in the lime content up to 8 %. Beyond 8 %, the unconfined compressive strength decreased. The dry unit weight of the reference mix decreased, and the optimum moisture content increased with the addition of coir fibre. The unconfined compressive strength of the bentonite + 8 % lime mix increased up to 4 % with the gypsum. Beyond 4 %, the unconfined compressive strength decreased. The unconfined compressive strength of the reference mix increased with the addition of coir fibre up to a fibre content of 1.5 %. The unconfined compressive strength of the reference mix-coir fibre composite was less in comparison to the reference mix. The unconfined compressive strength of the bentonite increased with the addition of lime and gypsum and with the increase in the curing period. The improvement in the post-peak region was better for the reference mix with reinforced coir fibres as compared to the unreinforced reference mix. The improved post-peak behaviour of the bentonite-lime-gypsum-coir fibre mixture could boost the construction of temporary roads on such problematic soils. Further, its use will also provide an environmental motivation for providing a means of consuming large quantities of coir fibres. 13. Evaluation of digital model accuracy and time-dependent deformation of alginate impressions. Science.gov (United States) Cesur, M G; Omurlu, I K; Ozer, T 2017-09-01 The aim of this study was to evaluate the accuracy of digital models produced with the three-dimensional dental scanner, and to test the dimensional stability of alginate impressions for durations of immediately (T0), 1 day (T1), and 2 days (T2). A total of sixty impressions were taken from a master model with an alginate, and were poured into plaster models in three different storage periods. Twenty impressions were directly scanned (negative digital models), after which plaster models were poured and scanned (positive digital models) immediately. The remaining 40 impressions were poured after 1 and 2 days. In total, 9 points and 11 linear measurements were used to analyze the plaster models, and negative and positive digital models. Time-dependent deformation of the alginate impressions and the accuracy of the conventional plaster models and digital models were evaluated separately. Plaster models, negative and positive digital models showed significant differences in nearly all measurements at T (0), T (1), and T (2) times (P 0.05), but they demonstrated statistically significant differences at T (2) time (P impressions is practicable method for orthodontists. 14. Evaluation of point plaster therapy with ginger powder in preventing nausea and vomiting occurred after platinum-based interventional chemotherapy in patients with primary or metastatic liver cancer International Nuclear Information System (INIS) Lu Haiyan; Yang Yang; Meng Zhiqiang; Chen Leihua 2010-01-01 Objective: To evaluate the point plaster therapy with ginger powder combined with ondansetron hydrochloride in preventing nausea and vomiting usually occurred after platinum-based interventional chemotherapy in patients with primary or metastatic liver cancer, and to compared its effectiveness with that by using ondansetron hydrochloride only. Method: Sixty-two patients with primary or metastatic liver cancer, who were scheduled to receive platinum-based interventional chemotherapy, were randomly and equally divided into two groups with 31 cases in each group. The patients in the study group (n = 31) were given point plaster therapy, i.e. externally applying ginger powder (20 g) to the point of Shenque, for four days together with arterial infusion of ondansetron hydrochloride (8 mg) during interventional procedure,while the patients in the control group (n = 31) were given point plaster therapy with placebo (potato powder) together with arterial infusion of ondansetron hydrochloride (8 mg) during interventional procedure. The questionnaire of INVR (index form for evaluating nausea and vomiting) was used to assess the effectiveness, and the results were compared between two groups. Results: The incidence of nausea and vomiting in study group was significantly lower than that in control group at all observed points of time during the period of 0 -72 hours after the treatment (P 0.05). After the treatment the scores of nausea, vomiting and retching in the study group were 0.45, 0.25 and 0.19 respectively, while these in the control group were 2.77, 0.87 and 0.97 respectively, the differences between two groups were statistically significant (P < 0.05). Conclusion: The external application of ginger powder to points of Shenque can markedly decrease the incidence and severity of nausea and vomiting after platinum-based interventional chemotherapy in patients with primary or metastatic liver cancer. (authors) 15. Wall Painting Investigation by Means of Non-invasive Terahertz Time-Domain Imaging (THz-TDI): Inspection of Subsurface Structures Buried in Historical Plasters Science.gov (United States) Dandolo, Corinna Ludovica Koch; Jepsen, Peter Uhd 2016-02-01 Characterization of subsurface features of wall paintings is important in conservation and technical art history as well as in building archaeology and architecture fields. In this study, an area of the apsidal wall painting of Nebbelunde Church (Rødby, Denmark) has been investigated by means of terahertz time-domain imaging (THz-TDI). Subsurface structures have been detected at different depths inside the lime-based plaster of the wall painting until approximately 1 cm from the surface. The surface morphology of the buried structures has been 3D imaged in detail, providing a substantial contribution in their characterization. 16. NANOTECHNOLOGY IN THE CULTURAL HERITAGE - INFLUENCE OF NANOSPENSIONS ADOPTED BY NANOPARTICLES OF TiO2 FOR CLEANING THE SURFACE OF HISTORICAL PLASTERS Directory of Open Access Journals (Sweden) Klára Kroftová 2017-10-01 Full Text Available The continuous development of nanostructure and the study of physico - chemical processes in the nanometer range lead to new methods that can slow down the degradation processes of a work of art, or even restore damage caused, for example, by an inappropriate restoration process. The use of nanosuspensions based on calcium hydroxide is probably the most widespread application of nanomaterials in heritage care, especially in the field of hardening of lime building materials (plaster, limestone, etc.. In combination with titanium dioxide, it should be a successful suspension in the fight against biological agents, surface contamination or in the protection of UV-resistant building materials. 17. Determination of Radium 226 in mexican phosphate fertilizers and gypsum by gamma spectrometry.; Determinacion de Radio 226 en fertilizantes fosfatados y en yeso mediante espectrometria gamma. Energy Technology Data Exchange (ETDEWEB) Godinez A, M C 1996-12-31 The {sup 226} Ra isotope was determined in 17, 20 and 46% m/m phosphate fertilizers and gypsum. The samples of the fertilizers were dissolved in 10% v/v nitric acid solutions. The barium sulphate method was used for the precipitation of {sup 226} Ra. On the other hand, alkaline fusion method was used to separate the {sup 226} Ra from gypsum. The results indicated that {sup 226} Ra was present in the phosphate fertilizers and gypsum. The {sup 226} Ra concentrations present in these materials were between 10 {sup -4} - 10 {sup -5} {mu}g g{sup -1}. (Author). 18. Origin and diagenetic evolution of gypsum and microbialitic carbonates in the Late Sag of the Namibe Basin (SW Angola) Science.gov (United States) Laurent, Gindre-Chanu; Edoardo, Perri; Ian, Sharp R.; Peacock, D. C. P.; Roger, Swart; Ragnar, Poulsen; Hercinda, Ferreira; Vladimir, Machado 2016-08-01 Ephemeral evaporitic conditions developed within the uppermost part of the transgressive Late Sag sequence in the Namibe Basin (SW Angola), leading to the formation of extensive centimetre- to metre-thick sulphate-bearing deposits and correlative microbialitic carbonates rich in pseudomorphs after evaporite crystals. The onshore pre-salt beds examined in this study are located up to 25 m underneath the major mid-Aptian evaporitic succession, which is typified at the outcrop by gypsiferous Bambata Formation and in the subsurface by the halite-dominated Loeme Formation. Carbonate-evaporite cycles mostly occur at the top of metre-thick regressive parasequences, which progressively onlap and overstep landward the former faulted (rift) topography, or fill major pre-salt palaeo-valleys. The sulphate beds are made up of alabastrine gypsum associated with embedded botryoidal nodules, dissolution-related gypsum breccia, and are cross-cut by thin satin-spar gypsum veins. Nodular and fine-grained fabrics are interpreted as being diagenetic gypsum deposits resulting from the dissolution and recrystallisation of former depositional subaqueous sulphates, whereas gypsum veins and breccia result from telogenetic processes. The carbonates display a broader diversity of facies, characterised by rapid lateral variations along strike. Thin dolomitic and calcitic bacterial-mediated filamentous microbialitic boundstones enclose a broad variety of evaporite pseudomorphs and can pass laterally over a few metres into sulphate beds. Dissolution-related depositional breccias are also common and indicate early dissolution of former evaporite layers embedded within the microbialites. Sulphate and carbonate units are interpreted as being concomitantly deposited along a tide-dominated coastal supra- to intertidal- sabkha and constitute high-frequency hypersaline precursor events, prior to the accumulation of the giant saline mid-Aptian Bambata and Loeme Formations. Petrographic and geochemical 19. EVALUATION OF CEMENT THIXOTROPY FOR THE CEMENT OF OIL WELLS IN AREAS WITH LOSSES: EFFECT OF PLASTER AND DAIRY OF HIGH FURNACES Directory of Open Access Journals (Sweden) T. Bouziani 2010-12-01 Full Text Available Cementing of oil and gas wells can be a very delicate operation. Among the concerns of service companies, during this operation are the nature and conditions of the formations in well. This is the case of cementing operations in southern Algeria, specifically on the fields of In-Amen, where the formations in lost zones are naturally weak and highly permeable. In these areas, drilling fluids (muds and cements pumped will be, completely or partially lost, what we call "lost circulation". Thixotropic cements are useful to overcome lost circulation problems. They are characterized by a special rheological behavior, allowing it to plug lost zones when they are pumped. Our work aims to assess the thixotropy of cements perapred with two types of cement (class G Asland cement and CEM I 42.5 portland cement with the plaster, using a viscometer with coaxial cylinder (couette type. Moreover, the effect of blast furnace slag (LHF on the properties and thixotropic mixtures prepared was also studied. The results show that portland cement (available locally can produce mixes with higher and more stable thixotropy than the class G cement (from importation, which is a practical and economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster. 20. EVALUATION OF THE THIXOTROPY OF OIL-WELL CEMENTS USED FOR CEMENTING LOST CIRCULATION ZONES: EFFECT OF PLASTER AND BLAST FURNACE SLAG Directory of Open Access Journals (Sweden) T. Bouziani 2015-08-01 Full Text Available Cementing of oil and gas wells can be a very delicate operation. Among the concerns of service companies, during this operation are the nature and conditions of the formations in well. This is the case of cementing operations in southern Algeria, specifically on the fields of In-Amen, where the formations in lost zones are naturally weak and highly permeable. In these areas, drilling fluids (muds and cements pumped will be, completely or partially lost, what we call "lost circulation". Thixotropic cements are useful to overcome lost circulation problems. They are characterized by a special rheological behavior, allowing it to plug lost zones when they are pumped.Our work aims to assess the thixotropy of cements perapred with two types of cement (class G Asland cement and CEM I 42.5 portland cement with the plaster, using a viscometer with coaxial cylinder (couette type. Moreover, the effect of blast furnace slag (LHF on the properties and thixotropic mixtures prepared was also studied. The results show that portland cement (available locally can produce mixes with higher and more stable thixotropy than the class G cement (from importation, which is a practical and economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster. 1. Technical Note: Historic gypsum-kilns (Morata de Tajuña, Madrid Directory of Open Access Journals (Sweden) Llamas Borrajo, J. F. 2007-08-01 Full Text Available In the locality of Morata de Tajuña and surroundings there was an important settlement of gypsum pits and limekilns, together with other historical industries, now disappear. These activities were developed mainly during the 1960´s and 70´s, but its production decreased because of changes in the productive processes (substitution of discontinuous processes by continuous ones, higher kilns, etc. (1. Nevertheless, some of these furnaces still remain, as well as ancient workers who have provided important information. Within the research project funded by the Madrid´s Government, entitled: Industrial archaeology: Conservation of the mining and metallurgical heritage of Madrid (IV, ancient gypsum pits have been identified and inventoried. The ancient gypsiferous extraction history was recovered and the productive processes fluxes were reconstructed. The state of the heritage is evaluated and the conservation of some of the elements is recommended. Likewise, the intangible heritage was also investigated, being able to show a legend related with these kilns.En Morata de Tajuña y pueblos limítrofes hay una importante tradición yesera y calera, así como de otras industrias de materiales de la construcción ya desaparecidas, sobre todo en los años 60-70 del pasado siglo, debido a cambios en los sistemas productivos (paso de sistemas discontinuos a continuos, hornos mayores, etc. (1. Por eso aún se conservan algunos hornos y también viven antiguos productores, a los que hemos podido preguntar sobre los procesos productivos. En el marco de un proyecto de investigación de la Consejería de Educación de la Comunidad de Madrid titulado âArqueología Industrial: conservación del patrimonio minero-metalúrgico madrileño (IVâ se están identificando e inventariando viejas yeserías, recuperando la historia yesera local, reconstruyendo los flujos productivos y entrevistando a antiguos operarios. De esta manera, se pretende evaluar 2. Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast-An in vitro Study. Science.gov (United States) Madhavan, Ranjith; George, Navia; Thummala, Niharika R; Ravi, S V; Nagpal, Ajay 2017-11-01 For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with self-disinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness. Difference in surface hardness was statistically insignificant (p > 0.05). Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable. Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material. 3. A study of the effectiveness of the use of gypsum and volcanic ash against the stability of clay soil in terms of UCT and CBR values Science.gov (United States) Roesyanto; Iskandar, R.; Hastuty, IP; Lubis, AIU 2018-02-01 Soil stabilization is an effort to improve engineering properties of soil. The conventional soil stabilization is by adding additives to the soil such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and volcanic ash. The research purposes were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% volcanic ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT values of original soil and original soil plus 2% gypsum were 1.40 kg/cm2 and 1.66 kg/cm2 respectively. The CBR soaked and unsoaked values of original soil were 4.44% and 6.28% correspondingly. Meanwhile, CBR soaked and CBR unsoaked values of original soil plus 2% gypsum were 6.74% and 8.02% respectively. The research results showed that the additives materials of gypsum and volcanic ash improved the engineering properties of clay. The UCT result from the stabilized soil by 2% gypsum and 10% volcanic ash gave value of 2.79 kg/cm2 (increased 99.28% from original soil). For CBR test, the most effective mixture were in variation of 2% gypsum and 9% volcanic ash which gave value of 9.07% (104.27% increase from original soil) for CBR soaked and 10.29% (63.85% increase from original soil) for CBR unsoaked. The stabilized soil with 2% gypsum and 9% volcanic ash was classified as CL based on USCS and was classified as A-6 (4) based on AASHTO classification system. 4. Factors affecting the precipitation of pure calcium carbonate during the direct aqueous carbonation of flue gas desulfurization gypsum International Nuclear Information System (INIS) Song, Kyungsun; Jang, Young-Nam; Kim, Wonbaek; Lee, Myung Gyu; Shin, Dongbok; Bang, Jun-Hwan; Jeon, Chi Wan; Chae, Soo Chun 2014-01-01 The mineral carbonation of FGD (flue gas desulfurization) gypsum was carried out through CO 2 sorption into ammonia solution containing FGD gypsum. High-purity calcium carbonate was precipitated from DCC (dissolved calcium carbonate) solution which was extracted during the induction period. The factors affecting the preparation of pure calcium carbonate were examined under the following conditions: CO 2 flow rate (1–3 L/min), ammonia content (4–12%), and S/L (solid-to-liquid) ratio (5–300 g/L). X-Ray diffraction study revealed that the PCC (precipitated calcium carbonate) was round-shaped vaterite. The induction time for PCC decreased as the CO 2 flow rate increased. The maximum formation efficiency for pure PCC was seen to increase linearly with the ammonia content. The formation efficiency for pure PCC was the highest (90%) for S/L ratio of 5 g/L but it decreased as S/L ratio increased. On the other hand, S/L ratio didn't affect the maximum solubility limit of DCC. It is believed that the pure PCC would add an economic value to the FGD gypsum carbonation for industrial CO 2 sequestration. - Highlights: • Pure and white CaCO 3 was synthesized using induction period during direct carbonation of FGD gypsum. • Its formation efficiency was increased with ammonia content but decreased with solid-to-liquid ratio. • This method is expected to extend to other industrial CO 2 sequestration for the enhanced economic value of precipitated CaCO 3 5. Synthesis of Fluorite (CaF2 Crystal from Gypsum Waste of Phosphoric Acid Factory in Silica Gel Directory of Open Access Journals (Sweden) Mohammad Misbah Khunur 2012-06-01 Full Text Available This paper report the synthesis and characterization of fluorite single crystal prepared from gypsum waste of phosphoric acid production in silica gel. Instead of its high calcium, gypsum was used to recycle the waste which was massively produces in the phosphoric acid production. The gypsum waste, the raw material of CaCl2 supernatant, was dissolved in concentrated HCl and then precipitated as calcium oxalate (CaC2O4 by addition of ammonium oxalate. The CaCl2 was obtained by dissolving the CaC2O4 with HCl 3M. The crystals were grown at room temperature in silica gel and characterized by AAS, FTIR and powder XRD. The optimum crystal growth condition, which is pH of gel, CaCl2 concentration and growth time, were investigated. The result shows that at optimum condition of pH 5.80, CaCl2 concentrations of 1.2 M, and growth time of 144 hours, colorless crystals with the longest size of 3 mm, were obtained (72.57%. Characterization of the synthesized crystal by AAS indicates that the obtained crystal has high purity. Meanwhile, analysis by FTIR spectra shows a Ca–F peak at 775 cm-1, and powder-XRD analysis confirms that the obtained crystal was fluorite (CaF2. © 2012 BCREC UNDIP. All rights reservedReceived: 11st April 2012; Revised: 4th June 2012; Accepted: 13rd June 2012[How to Cite: M.M. Khunur, A. Risdianto, S. Mutrofin, Y.P. Prananto. (2012. Synthesis of Fluorite (CaF2 Crystal from Gypsum Waste of Phosphoric Acid Factory in Silica Gel. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 71-77. doi:10.9767/bcrec.7.1.3171.71-77 ][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.3171.71-77 ] | View in 6. Composting of waste paint sludge containing melamine resin as affected by nutrients and gypsum addition and microbial inoculation International Nuclear Information System (INIS) Tian Yongqiang; Chen Liming; Gao Lihong; Michel, Frederick C.; Wan Caixia; Li Yebo; Dick, Warren A. 2012-01-01 Melamine formaldehyde resins have hard and durable properties and are found in many products, including automobile paints. These resins contain high concentrations of nitrogen and, if properly composted, can yield valuable products. We evaluated the effects of starter compost, nutrients, gypsum and microbial inoculation on composting of paint sludge containing melamine resin. A bench-scale composting experiment was conducted at 55 °C for 91 days and then at 30 °C for an additional 56 days. After 91 days, the composts were inoculated with a mixed population of melamine-degrading microorganisms. Melamine resin degradation after the entire 147 days of composting varied between 73 and 95% for the treatments with inoculation of microorganisms compared to 55–74% for the treatments without inoculation. Degradation was also enhanced by nutrients and gypsum additions. Our results infer that large scale composting of melamine resins in paint sludge is possible. - Highlights: ► Melamine resin in waste paint sludges could be efficiently composted at bench scale. ► Melamine resin degradation after 147 days of composting was 73–95% complete. ► Nutrients, gypsum and melamine-degrading microorganisms increased composting rate. ► Melamine degradation products first increased and then decreased in the compost. ► Final compost was enriched in nitrogen and other essential plant nutrients. - Melamine resin in waste paint sludges was efficiently composted at bench scale, with finished composts having low levels of heavy metals and enriched in plant nutrients. 7. Remediation of saline-sodic soil with flue gas desulfurization gypsum in a reclaimed tidal flat of southeast China. Science.gov (United States) Mao, Yumei; Li, Xiaping; Dick, Warren A; Chen, Liming 2016-07-01 Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization (FGD)-gypsum applied at rates of 0, 15, 30, 45 and 60Mg/ha to remediate tidal flat soils of the Yangtze River estuary. Exchangeable sodium percentage (ESP), exchangeable sodium (ExNa), pH, soluble salt concentration, and composition of soluble salts were measured in 10cm increments from the surface to 30cm depth after 6 and 18months. The results indicated that the effect of FGD-gypsum is greatest in the 0-10cm mixing soil layer and 60Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil pH to neutral (7.0). The improvement effect was reached after 6months, and remained after 18months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na(+), HCO3(-)+CO3(2-) and Cl(-) to neutral salt ions mainly containing Ca(2+) and SO4(2-). Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising. Copyright © 2016. Published by Elsevier B.V. 8. Potential of Soil Amendments (Biochar and Gypsum in increasing Water Use Efficiency of Abelmoschus esculentus L. Moench Directory of Open Access Journals (Sweden) Aniqa eBatool 2015-09-01 Full Text Available Water being an essential component for plant growth and development, its scarcity poses serious threat to crops around the world. Climate changes and global warming are increasing the temperature of earth hence becoming an ultimate cause of water scarcity. It is need of the day to use potential soil amendments that could increase the plants’ resistance under such situations. Biochar and gypsum were used in the present study to improve the water use efficiency and growth of Abelmoschus esculentus L. Moench (Lady’s Finger. A six weeks experiment was conducted under greenhouse conditions. Stress treatments were applied after thirty days of sowing. Plant height, leaf area, photosynthesis, transpiration rate, stomatal conductance and water use efficiency were determined weekly under stressed (60% field capacity and non-stressed (100% field capacity conditions. Stomatal conductance and transpiration rate decreased and reached near to zero in stressed plants. Stressed plants also showed resistance to water stress upto five weeks and gradually perished at sixth week. On the other hand, water use efficiency improved in stressed plants containing biochar and gypsum as compared to untreated plants. Biochar alone is a better strategy to promote plant growth and WUE specifically of Abelmoschus esculentus, compared to its application in combination with gypsum. 9. Problems and possible remedies concerning NORM in by-Product gypsum produced by the phosphate industry International Nuclear Information System (INIS) Burnett, W.C.; Hull, C.D 1996-01-01 Large quantities (∼ 30 million tons/year) of phosphogypsum are produced as a by-product of fertilizer production in Florida. The sedimentary phosphate rock, used as the raw material for phosphoric acid production, is enriched in uranium and daughter products. Relatively high concentrations of some of these U-series daughters, particularly 226 Ra (av. = 910 Bq.Kg -1 ), prevent use of the by-product gypsum for construction or other purposes. The material is thus stockpiled on huge stacks which are unsightly and a potential threat to the surrounding air and especially groundwater resources. It is estimated that ∼ 10 9 tons of this material will be on Florida stacks by the turn of the century. We have been investigating the detailed radiochemistry of phosphogypsum in the hope that can understanding of how these radionuclides are fixed in the material may lead to cost-effective purification schemes. Our work has focused on the distribution of 226 Ra but has also included 210 Pb and 210 Po (av. = 860 Bq.Kg -1 ) which are also enriched in phosphogypsum. This paper summarizes the problems associated with this material and reviews its radiochemistry as elucidated by sequential extraction and other methodologies. We also present some possible alternatives to long-term storage as a solution to the phosphogypsum problem. (author) 10. Removal of Hg, As in FGD gypsum by different aqueous ammonia (amines) during CO2 sequestration. Science.gov (United States) Wenyi, Tan; Wenhui, Fan; Hongyi, Li; Zixin, Zhang; Yunkun, Zhu 2017-12-01 CO 2 sequestration by flue gas desulfurization gypsum (FGDG) has become a promising FGDG disposal technology due to simultaneous CO 2 emission reduction and FGDG conversion into calcium carbonate. In this paper, another merit of the novel technology, i.e., the removal of toxic elements (e.g., Hg and As) in FGDG, will be addressed for the first time. In three different aqueous ammonia (or amines) media, removal efficiencies of Hg and As in FGDG samples were evaluated during CO 2 sequestration. Higher than 90% and 20% removal efficiencies, respectively, for Hg and As are achieved at 40°C in aqueous ammonia media, but they decrease at elevated temperatures. Ammonia loss takes place at 80°C and pH varies greatly with temperatures in aqueous ammonia. This is disadvantageous for the formation of Hg-ammonia complexes and for the yield of carbonates, which are responsible for Hg or As re-adsorption. The sequential chemical extraction method suggests that the speciation changes of Hg are induced by FGDG carbonation, and that unstable Hg speciation in triethanolamine increases at elevated temperatures. 11. A comparative study of AMF diversity in annual and perennial plant species from semiarid gypsum soils. Science.gov (United States) Alguacil, M. M.; Torrecillas, E.; Roldán, A.; Díaz, G.; Torres, P. 2012-04-01 The arbuscular mycorrhizal fungi (AMF) communities composition regulate plant interactions and determine the structure of plant communities. In this study we analysed the diversity of AMF in the roots of two perennial gypsophyte plant species, Herniaria fruticosa and Senecio auricula, and an annual herbaceous species, Bromus rubens, growing in a gypsum soil from a semiarid area. The objective was to determine whether perennial and annual host plants support different AMF communities in their roots and whether there are AMF species that might be indicators of specific functional plant roles in these ecosystems. The roots were analysed by nested PCR, cloning, sequencing of the ribosomal DNA small subunit region and phylogenetic analysis. Twenty AMF sequence types, belonging to the Glomus group A, Glomus group B, Diversisporaceae, Acaulosporaceae, Archaeosporaceae and Paraglomeraceae, were identified. Both gypsophyte perennial species had differing compositions of the AMF community and higher diversity when compared with the annual species, showing preferential selection by specific AMF sequences types. B. rubens did not show host specificity, sharing the full composition of its AMF community with both perennial plant species. Seasonal variations in the competitiveness of AM fungi could explain the observed differences in AMF community composition, but this is still a working hypothesis that requires the analysis of further data obtained from a higher number of both annual and perennial plant species in order to be fully tested. 12. Indoor Pollution Emissions from Building Materials; Case of Study: Gypsum Boards Indoor Pollution Emissions from Building Materials; Case of Study: Gypsum Boards Directory of Open Access Journals (Sweden) Silverio Hernández Moreno 2012-02-01 Full Text Available Este reporte presenta una evaluación de las emisiones de materiales de construcción, al interior de los edificios que pueden causar daño a la salud de los usuarios durante la ocupación, pues emiten sustancias tóxicas al interior de los edificios. Este reporte presenta un caso de studio que evalúa a los tableros de yeso, frecuentemente usados en la construcción de muros divisorios y falsos plafones. La parte experimental se basa en un espacio tridimensional el cual simula un cuarto de cualquier tipo de edificación; por ejemplo: un salón de clases u oficina. Las condiciones ambientales al interior, tales como: ventilación, temperatura y humedad, afectan directamente las emisiones de sustancias químicas por los materiales de construcción. La metodología se basa en la comparación de materiales convencionales y materiales alternativos con distinta composición y similares características, en donde usamos métodos de prueba, condiciones ambientales, instrumentos y herramientas similares. Este es un estudio muy importante para entender los problemas relacionadoscon la contaminación ambiental, específicamente del aire y sus efectos en el interior de los edificios, y que se relaciona directamente con la salud pública e indirectamente con los sistemas constructivos y la selección de materiales en los edificios. Las pruebas concluyen que los materiales alternativos (de contenido reciclado son mejores que los tradicionales, porque reducen la contaminación del aire al interior de los edificios. This report presents an evaluation of emissions from indoor building materials that may cause health damage to the people who occupy the building, since these materials emit toxic chemicals into the air and indoor surfaces. This report presents a case study which evaluates Gypsum Boards, frequently used in the construction of dividing walls and ceilings. The experimental part of this report is based on a three-dimensional space that simulates a 13. A simple idea for reducing the cost and weight of plaster-cast orthoses Uma ideia simples para diminuir custo e peso das talas gessadas Directory of Open Access Journals (Sweden) André Esmanhotto 2013-01-01 Full Text Available OBJECTIVE: To reduce the cost and weight of plaster molded orthosis (increasing patient comfort, keeping the same resistance. METHODS: 22 plaster orthosis were analysed, 11 with conventional shape and 11 with pyramidal shape. It was compared, in theory (mathematcally and practice, the change of weight (and consequently cost and flexion resistance between conventional shape and pyramidal shape. RESULTS: Theorical analysis: weight and cost decrease of 26.7%-38.9%, according to the layers disposition of the cast. Laboratorial analysis: cast´s weight decrease of 34.5% (p = 0.000005 and resistance increase of 26.7% (p = 0.03. CONCLUSION: plaster molded orthosis made in a pyramidal shape, have a statistically significant decrease of weight (and consequently cost and statistically significant increase of resistance if compared with traditional shape. OBJETIVO: Diminuir o custo e o peso (aumentando o conforto para o paciente das talas gessadas, mantendo resistência semelhante. MÉTODOS: Foram analisadas 22 talas de gesso, 11 com formato convencional e 11 com formato piramidal. Foi feita comparação, teórica (matemática e prática, entre as talas convencionais e as piramidais quanto à mudança de peso (e consequentemente de custo e à resistência à flexão. RESULTADOS: Análise matemática – diminuição peso e custo entre 26,7% e 38,9%, variando conforme a disposição das camadas da tala. Análise prática – diminuição do peso em 34,5% (p = 0,000005 e resistência aumentada em 26,7% (p = 0,03. CONCLUSÃO: A tala gessada com formato piramidal apresenta diminuição estatisticamente significativa de peso (e consequentemente de custo, com aumento estatisticamente significativo da resistência, se comparada à tala de formato convencional. 14. Analyzing the rules of fracture and damage, and the characteristics of the acoustic emission signal of a gypsum specimen under uniaxial loading Science.gov (United States) Chen, Dong; Wang, En-yuan; Li, Nan 2017-08-01 In order to study the mechanism of rock bursts in a mined-out area of a gypsum mine, in this paper acoustic emission testing of the uniaxial compression of gypsum and sandstone samples is carried out. The case of rupture of the specimen is observed, and the load axial deformation curve and acoustic emission parameters are obtained for the whole process of specimen rupture. The similarities and differences between the gypsum and sandstone samples are determined in terms of their mechanical properties, their damage evolution laws and frequency band energy distributions, and the instantaneous energy characteristics of their acoustic emission. The results show that the main fracture morphology of gypsum is ‘eight’-type, and the macroscopic fracture morphology of sandstone is mainly of partial ‘Y’-type and inverted Y-type. The intensity and uniformity of the gypsum and sandstone of the medium are different; because the gypsum is more uniform, it does not show as much variation as sandstone, instead suddenly increasing and decreasing. The maximum value of the damage variable D of gypsum reached 1, but the maximum value of D of the sandstone only reached 0.9. The frequency band of the maximum energy of gypsum and sandstone gradually decreased across the the four stages of rupture, while the maximum energy percentage increased gradually. From the stage where damage gradually increases to the stage of integral fracture of the specimen, the instantaneous energy showed a certain degree of increase. With an increase in the strength of the sample, the maximum energy percentage of the two materials corresponding to each phase gradually increases, and from the stage where damage gradually increases to the stage of integral fracture of the specimen, the value of instantaneous energy obviously increases. The results indicate that gypsum mines will also experience rock bursts, as coal mines do, but the intensity will be different. Therefore, using the three indicators, the 15. Elastic wave velocity and acoustic emission monitoring during Gypsum dehydration under triaxial stress conditions Science.gov (United States) Brantut, N.; David, E. C.; Héripré, E.; Schubnel, A. J.; Zimmerman, R. W.; Gueguen, Y. 2010-12-01 Dehydration experiments were performed on natural Gypsum polycrystal samples coming from Volterra, Italy in order to study contemporaneously the evolution of P and S elastic wave velocities and acoustic emission (AE) triggering. During these experiments, temperature was slowly raised at 0.15 degrees C per minute under constant stress conditions. Two experiments were realized under quasi-hydrostatic stress (15 and 55 MPa respectively). The third experiment was realized under constant triaxial stress (σ3=45MPa, σ1=75MPa). All three were drained (10MPa constant pore pressure). In each experiments, both P and S wave velocities reduced drastically (as much as approx. 50% in the low confining pressure case) at the onset of dehydration. Importantly, the Vp/Vs ratio also decreased. Shortly after the onset of decrease in P and S wave velocities, the dehydration reaction was also accompanied by bursts of AEs. Time serie locations of the AEs show that they initiated from the pore pressure port, ie from where the pore fluid could easily be drained, and then slowly migrated within the sample. In each experiments, the AE rate could be positively correlated to the reaction rate, inferred from pore volumetry. In such a way, the AE rate reached a peak when the reaction was the fastest. Focal mechanism analysis of the largest AEs showed they had a large volumetric component in compaction, confirming that AEs were indeed related to pore closure and/or collapse. In addition, the AE rate also increased with confinement, ie when a larger amount of compaction was observed. Interestingly, when under differential stress conditions, AE focal mechanisms were mainly in shear. Additional dehydration experiments performed within an environmental scanning electron microscope under low vacuum highlight that, in drained conditions at least, the reaction seems to take place in two phases. First, cracks are being opened along cleavage planes within a single gypsum crystal, which allows for the 16. Natural and human-induced sinkholes in gypsum terrain and associated environmental problems in NE Spain Science.gov (United States) Benito, G.; Del Campo, P. Pérez; Gutiérrez-Elorza, M.; Sancho, C. 1995-04-01 The central Ebro Basin comprises thick evaporite materials whose high solubility produces typically karstic landforms. The sinkhole morphology developed in the overlying alluvium has been studied using gravimetry and ground-penetrating radar (GPR) on stream terraces, as well as analyzing the evolution of sinkhole morphologies observed in aerial photographs taken in 1928, 1957, and 1985. The sinkhole morphologies give some idea of possible subsurface processes as well as an indication of the final mechanisms involve in sinkhole development. On stream terraces and cover pediments the most commonly encountered dolines are bowl-shaped in their morphology with both diffuse and scarped edges. In contrast, dolines developed in the gypsiferous silt infilled valleys have a funnel and well-shaped morphology. The diffuse-edged bowl-shaped dolines are developed through the progressive subsidence of the alluvial cover, due to washing down of alluvial particles through small voids and cracks into deeper subsurface caves, resulting in a decrease alluvial density. Future compaction of the alluvial cover will produce surface subsidences. This type of dolines are associated with negative gravity anomalies. In contrast, the scarped-edge dolines are formed by the sudden collapse of a cavity roof. The cavities and cracks formed in the gypsum karst may migrate to the surface through the alluvial deposits by piping, and they may subsequently collapse. In this instance, the cavities can be detected by both gravity and GPR anomalies where the voids are not deeper than 4 5 m from the surface. These processes forming sinkholes can be enhanced by man-induced changes in the groundwater hydrologic regime by both inflows, due to irrigation, ditch losses, or pipe leakages, and by outflows from pumping activities. 17. Inhibition of hydrogen sulfide generation from disposed gypsum drywall using chemical inhibitors Energy Technology Data Exchange (ETDEWEB) Xu Qiyong [Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL 32611 (United States); School of Environment and Energy, Shenzhen Graduate School of Peking University, 518055, (China); Townsend, Timothy, E-mail: [email protected] [Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL 32611 (United States); Bitton, Gabriel [Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL 32611 (United States) 2011-07-15 Disposal of gypsum drywall in landfills has been demonstrated to elevate hydrogen sulfide (H{sub 2}S) concentrations in landfill gas, a problem with respect to odor, worker safety, and deleterious effect on gas-to-energy systems. Since H{sub 2}S production in landfills results from biological activity, the concept of inhibiting H{sub 2}S production through the application of chemical agents to drywall during disposal was studied. Three possible inhibition agents - sodium molybdate (Na{sub 2}MoO{sub 4}), ferric chloride (FeCl{sub 3}), and hydrated lime (Ca(OH){sub 2}) - were evaluated using flask and column experiments. All three agents inhibited H{sub 2}S generation, with Na{sub 2}MoO{sub 4} reducing H{sub 2}S generation by interrupting the biological sulfate reduction process and Ca(OH){sub 2} providing an unfavorable pH for biological growth. Although FeCl{sub 3} was intended to provide an electron acceptor for a competing group of bacteria, the mechanism found responsible for inhibiting H{sub 2}S production in the column experiment was a reduction in pH. Application of both Na{sub 2}MoO{sub 4} and FeCl{sub 3} inhibited H{sub 2}S generation over a long period (over 180 days), but the impact of Ca(OH){sub 2} decreased with time as the alkalinity it contributed was neutralized by the generated H{sub 2}S. Practical application and potential environmental implications need additional exploration. 18. An exploratory microdialysis study investigating the effect of repeated application of a diclofenac epolamine medicated plaster on prostaglandin concentrations in skeletal muscle after standardized physical exercise. Science.gov (United States) Burian, Angela; Frangione, Valeria; Rovati, Stefano; Mautone, Giuseppe; Leuratti, Chiara; Vaccani, Angelo; Crevenna, Richard; Keilani, Mohammad; Burian, Bernhard; Brunner, Martin; Zeitlinger, Markus 2013-12-01 Muscle injuries and extensive exercise are associated with cyclo-oxygenase dependent formation of inflammatory prostaglandins. Since the effect of topical administration of non-steroidal anti-inflammatory drugs (NSAIDs) on local cyclo-oxygenase is unknown, the present exploratory, open label, non-randomized study set out to measure exercise induced release of prostaglandins before and after epicutaneous administration of diclofenac. Microdialysis was used to determine the local interstitial concentration of PGE2 and 8-iso-PGF2α as well as diclofenac concentrations in the vastus lateralis under rest, dynamic exercise and during recovery in 12 healthy subjects at baseline and after a treatment phase applying a total of seven plasters medicated with 180 mg of diclofenac epolamine over 4 days. At baseline PGE2 concentrations were 1169 ± 780 pg ml(-1) at rest and 1287 ± 459 pg ml(-1) during dynamic exercise and increased to 2005 ± 1126 pg ml(-1) during recovery. After treatment average PGE2 concentrations were 997 ± 588 pg ml(-1) at rest and 1339 ± 892 pg ml(-1) during exercise. In contrast with the baseline phase no increase in PGE2 concentrations was recorded during the recovery period after treatment (PGE2 1134 ± 874 pg ml(-1)). 8-iso-PGF2α was neither affected by exercise nor by treatment with diclofenac. Local and systemic concentrations of diclofenac were highly variable but comparable with previous clinical pharmacokinetic studies. We can hypothesize an effect of topical diclofenac epolamine plaster on limiting the increase of local concentrations of the pro-inflammatory prostaglandin PGE2 induced in the muscle of healthy human subjects following standardized physical exercise. No effect of diclofenac treatment on 8-iso-PGF2α concentrations was observed, mainly since isoprostane is produced by a free radical-catalyzed lipid peroxidation mechanism independent of cyclo-oxygenases. © 2013 The Authors. British Journal of Clinical Pharmacology © 2013 The 19. Natural radioactivity of the cement, lime and plaster in the Zacatecas State; Radiactividad natural del cemento, cal y yeso en el Estado de Zacatecas Energy Technology Data Exchange (ETDEWEB) Mireles, F.; Davila, J. I.; Lopez, H.; Pinedo, J. L.; Rios, C.; Saucedo, S. A.; Cespedes, N., E-mail: [email protected] [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico) 2012-10-15 The construction materials are the main radiation gamma source inside the houses room and the buildings, followed by the terrestrial and cosmic radiation. The radioactivity levels of the construction materials were obtained to establish reference levels and of population exposure. In this work the study of 56 samples of construction materials is presented, 24 of cement, 20 of lime and 12 of plaster, of the marks more sold in the municipalities of Zacatecas and Guadalupe of the Zacatecas State, Mexico. The objective is the study of the concentration in activity of the radioisotopes {sup 238}U, {sup 232}Th, {sup 40}K and {sup 137}Cs, using a gamma rays spectrometry system based on a hyper pure germanium detector. The obtained results of activity concentration of the interest radioisotopes show similar values average to those published by UNSCEAR 1993. The population of the municipalities of Zacatecas and Guadalupe is exposed to the environmental gamma radiation coming from the contained radioisotopes in the construction materials; the annual equivalent effective dose by the cement is in the range of 116 at 562 {mu}Sv a{sup -1} with an average of 340 {mu}Sv a{sup -1}, of the lime is in the range of 36 at 212 {mu}Sv a{sup -1} with an average of 87 {mu}Sv a{sup -1}, and of the plaster is in the range of 16 at 27 {mu}Sv a{sup -1} with an average of 22 {mu}Sv a{sup -1}, this exposure does not represent any risk for the population's health. (Author) 20. Radon exhalation in some building construction materials and effect of plastering and paints on the radon exhalation rate using fired bricks International Nuclear Information System (INIS) Sharma, Anil; Mahur, A.K.; Rajendra Prasad; Sonkawade, R.G.; Sharma, A.C. 2013-01-01 The technological endeavors of human beings have modified the levels of radiation exposure slightly. The emanation of radon is primarily associated with radium and its ultimate precursor uranium. The radiation dose received by human beings from indoor radon and its progeny is the largest of all doses received either by natural or man-made sources. In order to investigate the effect of paints available in the market on the radon exhalation rate from building materials, several bricks were collected. These bricks were plastered with a mixture of cement and sand. Before measurements bricks were dried for 24 hours. These plastered bricks were then coated with white wash and again dried for 1- 2 hours. After drying the bricks were coated with different brands and colors of paints. Radon exhalation rates measurements were carried out for these painted bricks using 'Sealed can Technique' cylindrical plastic 'Can' of 7.5 cm height and 7.0 cm diameter was sealed to the individual samples by plastic can. In each 'Can' a LR-115 type II plastic detector (2 cm 2cm) was fixed at the top inside of the 'Can', such that the sensitive surface of the detector faces the material and is freely exposed to the emergent radon. Radon decays in the volume of the can record the alpha particles resulting from the 218 Po and 214 Po deposited on the inner wall of the 'Can'. Radon and its daughters will reach an equilibrium in concentration after one week or more. Hence the equilibrium activity of the emergent radon can be obtained from the geometry of the can and the time of exposure. The results will be discussed. (author) 1. In situ flash X-ray observation of projectile penetration processes and crater cavity growth in porous gypsum target analogous to low-density asteroids Science.gov (United States) Yasui, Minami; Arakawa, Masahiko; Hasegawa, Sunao; Fujita, Yukihiro; Kadono, Toshihiko 2012-11-01 projectile mass, was successfully fitted by a power law equation when another scaling parameter was used for the crater formation in strength regime, πY=Yt/ρtvi2, where Yt is the target material strength, as follows: πV=1.69×10-1πY-0.51. As a result, the crater formed on porous gypsum was revealed to be more than one order of magnitude smaller than that formed on basalt. Based on our experimental results, which visualize how crater cavities on porous cohesive materials grow with projectile penetration, we are able to discuss compression and excavation processes during crater formation quantitatively. This observation enables us to investigate and revise numerical models and crater scaling laws for high-velocity impacts into porous cohesive materials. 2. Pore formation during dehydration of a polycrystalline gypsum sample observed and quantified in a time-series synchrotron X-ray micro-tomography experiment Directory of Open Access Journals (Sweden) F. Fusseis 2012-03-01 Full Text Available We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm3 proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time. We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process. Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (20483 voxels in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway. Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the 3. Pore formation during dehydration of polycrystalline gypsum observed and quantified in a time-series synchrotron radiation based X-ray micro-tomography experiment Science.gov (United States) Fusseis, F.; Schrank, C.; Liu, J.; Karrech, A.; Llana-Fúnez, S.; Xiao, X.; Regenauer-Lieb, K. 2011-10-01 We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm3 proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time. We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process. Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (6.4 × 109 voxel each) in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway. Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the advance of the front are coupled in a feedback loop. We 4. Pore formation during dehydration of a polycrystalline gypsum sample observed and quantified in a time-series synchrotron X-ray micro-tomography experiment Science.gov (United States) Fusseis, F.; Schrank, C.; Liu, J.; Karrech, A.; Llana-Fúnez, S.; Xiao, X.; Regenauer-Lieb, K. 2012-03-01 We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm3 proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time. We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process. Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (20483 voxels) in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway. Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the advance of the front are coupled in a feedback loop. 5. Uptake and speciation of uranium in synthetic gypsum (CaSO4•2H2O): Applications to radioactive mine tailings. Science.gov (United States) Lin, Jinru; Sun, Wei; Desmarais, Jacques; Chen, Ning; Feng, Renfei; Zhang, Patrick; Li, Dien; Lieu, Arthur; Tse, John S; Pan, Yuanming 2018-01-01 Phosphogypsum formed from the production of phosphoric acid represents by far the biggest accumulation of gypsum-rich wastes in the world and commonly contains elevated radionuclides, including uranium, as well as other heavy metals and metalloids. Therefore, billions-of-tons of phosphogypsum stockpiled worldwide not only possess serious environmental problems but also represent a potential uranium resource. Gypsum is also a major solid constituent in many other types of radioactive mine tailings, which stems from the common usage of sulfuric acid in extraction processes. Therefore, management and remediation of radioactive mine tailings as well as future beneficiation of uranium from phosphogysum all require detailed knowledge about the nature and behavior of uranium in gypsum. However, little is known about the uptake mechanism or speciation of uranium in gypsum. In this study, synthesis experiments suggest an apparent pH control on the uptake of uranium in gypsum at ambient conditions: increase in U from 16 μg/g at pH = 6.5 to 339 μg/g at pH = 9.5. Uranium L 3 -edge synchrotron X-ray absorption spectroscopic analyses of synthetic gypsum show that uranyl (UO 2 ) 2+ at the Ca site is the dominant species. The EXAFS fitting results also indicate that uranyl in synthetic gypsum occurs most likely as carbonate complexes and yields an average U-O distance ∼0.25 Å shorter than the average Ca-O distance, signifying a marked local structural distortion. Applications to phosphogypsum from the New Wales phosphoric acid plant (Florida, USA) and uranium mine tailings from the Key Lake mill (Saskatchewan, Canada) show that gypsum is an important carrier of uranium over a wide range of pH and controls the fate of this radionuclide in mine tailings. Also, development of new technologies for recovering U from phosphogypsum in the future must consider lattice-bound uranyl in gypsum. Copyright © 2017 Elsevier Ltd. All rights reserved. 6. Growth of cowpea plants inoculated with Rhizobium in a saline-sodic soil after application of gypsum Directory of Open Access Journals (Sweden) Angela Jessyka Pereira Brito Fontenele Full Text Available Two experiments were carried out with the aim of evaluating the growth of cowpea cultivated in saline-sodic soils corrected with gypsum: one experiment in the laboratory, to identify the best level of gypsum for the correction of the saline-sodic soils of the state of Pernambuco, Brazil; and the other in a greenhouse, after correction of the soils. As the test plant, the cowpea cultivar pele de moça, inoculated with Rhizobium strain BR3267 was used. The experiments were arranged in a randomised block design in a 2 x 5 factorial arrangement, two soils and five levels of the gypsum requirement (GR, equivalent to 50, 100, 150, 200 and 250% of the GR of the soil, as determined by the Schoonover M-1 method, with five replications. The following were evaluated: electrical conductivity of the soil saturation extract (EC, soil exchangeable sodium and percentage of soil exchangeable sodium (ESP, number of nodules (NN, nodule dry weight (NDW, shoot dry weight (SDW, shoot height (PH and nitrogen concentration (N in the shoots. Application of 100% of the GR, followed by the enough water for leaching, was effective for the correction of soil sodicity. The application of increasing levels of soil GR resulted in an increase in the number of nodules, dry weight of the nodules and shoots, and the height and levels of N absorbed by the plants in soil S2. In soil S1, the use of levels of 200 and 250% of soil the GR caused a decrease in all the variables under study. 7. Determination of boron content and isotopic composition in gypsum by inductively coupled plasma optical emission spectroscopy and positive thermal ionization mass spectrometry using phase transformation. Science.gov (United States) Ma, Yun-Qi; Peng, Zhang-Kuang; Yang, Jian; Xiao, Ying-Kai; Zhang, Yan-Ling 2017-12-01 As a stable isotope, boron plays an important role in hydrogeology, environmental geochemistry, ore deposit geochemistry and marine paleoclimatology. However, there is no report of boron isotopic composition in gypsum. This is mainly confined to complete dissolution of Gypsum by water or acid. In this study, gypsum was converted to calcium carbonate (CaCO 3 ) with ammonium bicarbonate(NH 4 HCO 3 ) by two steps at 50°C. In every step, the mass ratio of NH 4 HCO 3 /CaSO 4 ·2H 2 O was twice, and conversion rate reached more than 98%. Converted CaCO 3 was totally dissolved with hydrochloric acid (the dissolution rate was over 99%). In order to overcome the difficulties of the matrix interference and the detection limit of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), we use Amberlite IRA 743 resin to purify and enrichment the boron at first, then eluting boron from the resin with 10mL 0.1mol/L hydrochloric acid at 75°C. The boron isotopic composition of natural gypsum samples was determined using positive thermal ionization mass spectrometry (P-TIMS). The boron isotopic composition of gypsum may be an excellent indicator for the formation environment. Copyright © 2017 Elsevier B.V. All rights reserved. 8. Bacterial communities and the nitrogen cycle in the gypsum soils of Cuatro Ciénegas Basin, coahuila: a Mars analogue. Science.gov (United States) López-Lozano, Nguyen E; Eguiarte, Luis E; Bonilla-Rosso, Germán; García-Oliva, Felipe; Martínez-Piedragil, Celeste; Rooks, Christine; Souza, Valeria 2012-07-01 The OMEGA/Mars Express hyperspectral imager identified gypsum at several sites on Mars in 2005. These minerals constitute a direct record of past aqueous activity and are important with regard to the search of extraterrestrial life. Gale Crater was chosen as Mars Science Laboratory Curiosity's landing site because it is rich in gypsum, as are some desert soils of the Cuatro Ciénegas Basin (CCB) (Chihuahuan Desert, Mexico). The gypsum of the CCB, which is overlain by minimal carbonate deposits, was the product of magmatic activity that occurred under the Tethys Sea. To examine this Mars analogue, we retrieved gypsum-rich soil samples from two contrasting sites with different humidity in the CCB. To characterize the site, we obtained nutrient data and analyzed the genes related to the N cycle (nifH, nirS, and nirK) and the bacterial community composition by using 16S rRNA clone libraries. As expected, the soil content for almost all measured forms of carbon, nitrogen, and phosphorus were higher at the more humid site than at the drier site. What was unexpected is the presence of a rich and divergent community at both sites, with higher taxonomic diversity at the humid site and almost no taxonomic overlap. Our results suggest that the gypsum-rich soils of the CCB host a unique microbial ecosystem that includes novel microbial assemblies. 9. The Effect of Kerqin Shangtong Plaster together with Adhesive Plaster Fixation in Treating Lateral Collateral Ligament Sprain of Ankle Joint%外敷科尔沁伤痛贴胶布固定治疗踝关节外侧副韧带扭伤 Institute of Scientific and Technical Information of China (English) 刘宝音; 吉日嘎拉 2012-01-01 Objective: To investigate the therapeutic method for lateral collateral ligament sprain of ankle joint. Methods: 49 patients with this sprain were treated with medicinal plaster, combined with adhesive plaster fixation. Results: The recovery of 43 cases was perfect and that of 6 cases was good. Conclusion: This method possesses the advantages of short course of disease and satisfactory curative effect.%目的：探讨踝关节外侧副韧带扭伤治疗方法.方法：对49例踝关节外侧副韧带扭伤采用患处外敷药贴胶布固定法的治疗.结果：49例中优43例,占88%;良6例,占12%.结论：患处外敷药贴胶布固定治疗踝关节外侧副韧带扭伤疗程短,疗效显著. 10. Reciclado de placas de yeso laminado aligeradas con residuos de poliuretano = Recycling of gypsum plasterboard lightened with polyurethane waste Directory of Open Access Journals (Sweden) Lourdes Alameda 2015-05-01 Full Text Available Este trabajo presenta los resultados de un proceso experimental de reutilización de residuos obtenidos de desechos de placas de yeso laminado elaboradas con residuos poliméricos de origen industrial (espuma de poliuretano y reforzadas con fibras de polipropileno, para la fabricación de nuevas placas de yeso laminado. Para ello, se expone la metodología de reciclado de placas prefabricadas buscando de esta forma aumentar el ciclo de vida del yeso y de los residuos de poliuretano empleados. Para ello se detalla el proceso de fabricación las nuevas placas así como su caracterización mediante ensayos físicos y mecánicos a través de ensayos normalizados para placas de yeso laminado (densidad aparente, resistencia a flexión, absorción total en agua y dureza superficial. Los resultados obtenidos indican que es posible reciclar este tipo de prefabricados de una manera sencilla. De la misma forma se ha demostrado que las nuevas placas fabricadas con el residuo recuperado, presentan un buen comportamiento mecánico, a la par que se reduce su capacidad de absorción de agua y se aumenta su dureza su superficial. Abstract This paper presents the results of an experimental process of reusing waste obtained from waste gypsum plasterboard made from polymeric industrial waste (polyurethane foam and polypropylene fibers whit the aim to manufacturer new gypsum plasterboards. Therefore, a methodology to recycle is presented to increase the life cycle of waste gypsum. The manufacturing process of the plates is detailed as well as their physical and mechanical characterization by means of standardized for gypsum plasterboard (bulk density, flexion strength, total water absorption and surface hardness. The results indicate that it is possible to recycle this type of prefabricated in a simple way. Likewise it has been demonstrated that new plates made with the residue reusing, have good mechanical strength, at the same time reduce the capacity of water 11. Relative Shock Effects in Mixed Powders of Calcite, Gypsum, and Quartz: A Calibration Scheme from Shock Experiments Science.gov (United States) Bell, Mary S. 2009-01-01 The shock behavior of calcite and gypsum is important in understanding the Cretaceous/Tertiary event and other terrestrial impacts that contain evaporite sediments in their targets. Most interest focuses on issues of devolatilization to quantify the production of CO2 or SO2 to better understand their role in generating a temporary atmosphere and its effects on climate and biota [e.g., papers in 1,2,3,4]. Devolatilization of carbonate is also important because the dispersion and fragmentation of ejecta is strongly controlled by the expansion of large volumes of gas during the impact process as well [5,6]. Shock recovery experiments for calcite yield seemingly conflicting results: early experimental devolatilization studies [7,8,9] suggested that calcite was substantially outgassed at 30 GPa (> 50%). However, the recent petrographic work of [10,11,12] presented evidence that essentially intact calcite is recovered from 60 GPa experiments. [13] reported results of shock experiments on anhydrite, gypsum, and mixtures of those phases with silica. Their observations indicate little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another (preliminary) report of shock experiments on calcite, anhydrite, and gypsum, [14] observe calcite recrystallization when shock loaded at 61 GPa, only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa. [15] shock loaded anhydrite and quartz to a peak pressure of 60 GPa. All of the quartz grains were trans-formed to glass and the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggest that recrystallization of anhydrite grains is the result of a solid state transformation. [16] reanalyzed the calcite and anhydrite shock 12. Use of the “red gypsum” industrial waste as substitute of natural gypsum for commercial cements manufacturing Directory of Open Access Journals (Sweden) Gázquez, M. J. 2012-06-01 Full Text Available The main objective of this research has been the valorisation of a waste from the TiO2 production process (sulphate method, called red gypsum, in the production of cements. This waste is mainly formed by di-hydrate calcium sulphate and iron hydroxides. To cover this objective it has been necessary to perform the physico-chemical characterisation of the red gypsum as well as the main components in the production of cements and of the new cements generated. Moreover, for the red gypsum, has been analyzed its radioactive content because it is generated in a NORM (Naturally Occurring Radioactive Materials industry. Finally, the most important properties of the obtained cements with different proportions of red gypsum in their composition have been studied by comparing them with the standard ones obtained in a Portland cement. Lastly, we have demonstrated that the new cements fulfil all the quality tests imposed by the European legislation. El objetivo de esta investigación ha sido analizar la valorización de un residuo generado en el proceso de producción de dióxido de titanio (vía sulfato, denominado yeso rojo, en la producción de cementos. Dicho residuo está compuesto fundamentalmente por sulfato de calcio di-hidratado e hidróxidos de hierro. Para ello, ha sido necesaria la caracterización físico-química del yeso rojo, así como la de los otros componentes fundamentales en la fabricación de cementos y de los cementos generados con el mencionado residuo. Además, en el caso del yeso rojo, se ha analizado su contenido radiactivo al generarse éste en una industria NORM (Natural Occurring Radioactive Materials. Posteriormente, se han estudiado las propiedades más importantes de los cementos producidos con diferentes porcentajes de yeso rojo añadido, comparando estas mezclas con las propiedades de un cemento Portland comercial, comprobándose que se cumplen todas las normas Europeas de calidad exigibles. 13. Moisture parameters and fungal communities associated with gypsum drywall in buildings. Science.gov (United States) Dedesko, Sandra; Siegel, Jeffrey A 2015-12-08 Uncontrolled excess moisture in buildings is a common problem that can lead to changes in fungal communities. In buildings, moisture parameters can be classified by location and include assessments of moisture in the air, at a surface, or within a material. These parameters are not equivalent in dynamic indoor environments, which makes moisture-induced fungal growth in buildings a complex occurrence. In order to determine the circumstances that lead to such growth, it is essential to have a thorough understanding of in situ moisture measurement, the influence of building factors on moisture parameters, and the levels of these moisture parameters that lead to indoor fungal growth. Currently, there are disagreements in the literature on this topic. A literature review was conducted specifically on moisture-induced fungal growth on gypsum drywall. This review revealed that there is no consistent measurement approach used to characterize moisture in laboratory and field studies, with relative humidity measurements being most common. Additionally, many studies identify a critical moisture value, below which fungal growth will not occur. The values defined by relative humidity encompassed the largest range, while those defined by moisture content exhibited the highest variation. Critical values defined by equilibrium relative humidity were most consistent, and this is likely due to equilibrium relative humidity being the most relevant moisture parameter to microbial growth, since it is a reasonable measure of moisture available at surfaces, where fungi often proliferate. Several sources concur that surface moisture, particularly liquid water, is the prominent factor influencing microbial changes and that moisture in the air and within a material are of lesser importance. However, even if surface moisture is assessed, a single critical moisture level to prevent fungal growth cannot be defined, due to a number of factors, including variations in fungal genera and 14. Removal of phosphorus, fluoride and metals from a gypsum mining leachate using steel slag filters. Science.gov (United States) Claveau-Mallet, Dominique; Wallace, Scott; Comeau, Yves 2013-03-15 The objective of this work was to evaluate the capacity of steel slag filters to treat a gypsum mining leachate containing 11-107 mg P/L ortho-phosphates, 9-37 mg/L fluoride, 0.24-0.83 mg/L manganese, 0.20-3.3 zinc and 1.7-8.2 mg/L aluminum. Column tests fed with reconstituted leachates were conducted for 145-222 days and sampled twice a week. Two types of electric arc furnace (EAF) slags and three filter sequences were tested. The voids hydraulic retention time (HRT(v)) of columns ranged between 4.3 and 19.2 h. Precipitates of contaminants present in columns were sampled and analyzed with X-ray diffraction at the end of tests. The best removal efficiencies over a period of 179 days were obtained with sequential filters that were composed of Fort Smith EAF slag operated at a total HRT(v) of 34 h which removed 99.9% of phosphorus, 85.3% of fluoride, 98.0% of manganese and 99.3% of zinc. Mean concentration at this system's effluent was 0.04 mg P/L ortho-phosphates, 4 mg/L fluoride, 0.02 mg/L manganese, 0.02 zinc and 0.5 mg/L aluminum. Thus, slag filters are promising passive and economical systems for the remediation of mining effluents. Phosphorus was removed by the formation of apatite (hydroxyapatite, Ca(5)(PO(4))(3)OH or fluoroapatite, Ca(5)(PO(4))(3)F) as confirmed by visual and X-ray diffraction analyses. The growth rate of apatite was favored by a high phosphorus concentration. Calcite crystals were present in columns and appeared to be competing for calcium and volume needed for apatite formation. The calcite crystal growth rate was higher than that of apatite crystals. Fluoride was removed by precipitation of fluoroapatite and its removal was favored by a high ratio of phosphorus to fluoride in the wastewater. Copyright © 2012 Elsevier Ltd. All rights reserved. 15. Influence of gypsum and farmyard manure on fertilizer zinc uptake by wheat and its residual effect on succeeding rice and wheat crops in a sodic soil International Nuclear Information System (INIS) Sachdev, P.; Deb, D.L. 1990-01-01 Greenhouse experiments were conducted to evaluate the effectiveness of gypsum and FYM on a sodic soil on fertilizer Zn uptake by wheat and residual effect on succeeding crops of rice and wheat. Application of FYM significantly increased the yield of first wheat crop as well as the yield of subsequent rice and wheat crops, but gypsum showed significant effect only on rice. FYM application also resulted in an increase in Zn content of all the three crops. Utilisation of the fertilizer Zn by the first crop of wheat ranged between 0.30 to 0.54 per cent while succeeding crop of rice utilised 1.00 to 1.25 per cent of the applied Zn. Application of gypsum to the first crop did not influence the fertilizer Zn uptake by wheat, rice and wheat, however, it significantly reduced the soil pH and increased the available Zn content in soil. (author). 15 refs., 6 tabs 16. Utilization of desulfurization gypsum to producing SO{sub 2} and CaO in multi-stage fluidized bed Energy Technology Data Exchange (ETDEWEB) Miao, Zhu; Wang, Tao; Yang, Hairui; Zhang, Hai; Zhang, Zuyi [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering 2013-07-01 With emission control becomes more and more stringent, flue gas desulphurization (FGD) is commonly employed for desulfurization. However, the product of FGD, gypsum, causes the unexpected environmental problems. How to utilize the byproduct of FGD effectively and economically is a challenging task. This paper proposed the new technical process to produce SO{sub 2} and CaO by reducing the gypsum in multi-stage fluidized bed reactor with different atmosphere. In addition, some preliminary experiments were carried out in PTGA. The results show that CO concentration has little effect on the initial decomposing temperature, but affect the decomposing rate of phosphogypsum obviously. The decomposing product composed of CaS and CaO simultaneously. The ratio of the two products was determined by CO concentration. Lower CO content benefits to produce more CO product and more SO{sub 2}. The decomposition reaction of phosphogypsum in reducing atmosphere is parallel competition reaction. Therefore, it is necessary to eliminate the effect of CaS and other byproduct efficiently by the new technology, which utilize multi-atmosphere in multistage fluidized bed reactors. 17. Simultaneous and continuous stabilization of As and Pb in contaminated solution and soil by a ferrihydrite-gypsum sorbent. Science.gov (United States) Kameda, Kentaro; Hashimoto, Yohey; Wang, Shan-Li; Hirai, Yasumasa; Miyahara, Hidetaka 2017-04-05 For the increasing need of stabilization both cationic and anionic metal(loid)s simultaneously, we newly developed a metal sorbent (FIXALL), consisting mainly of ferrihydrite and gypsum. The objectives of this study were to determine the molecular mechanisms of Pb and As stabilization in an aqueous system and to examine a simultaneous and long-term (up to 754days) effect on Pb and As stabilization in an anthropogenically contaminated soil using the FIXALL sorbent. When the solution contained a low concentration of Pb (5mgL -1 ), the mechanisms of Pb removal by FIXALL were based chiefly on the formation of inner-sphere surface complex with ferrihydrite. In the highly concentrated Pb solution (1200mgL -1 ), contrarily, the removal of Pb by FIXALL was the direct consequence of the dissolution of gypsum and subsequent precipitation of PbSO 4 , which strengthens the drawback of low capability of ferrihydrite for Pb removal. Regardless of initial concentrations, the primary mechanism of FIXALL for As stabilization is attributed to the formation of inner-sphere surface complex with ferrihydrite. A contaminated soil study demonstrated that FIXALL could decrease the concentration of water soluble As and Pb simultaneously and continuously for 754days without notable changes in their chemical species and soil pH. Copyright © 2016 Elsevier B.V. All rights reserved. 18. Successful lichen translocation on disturbed gypsum areas: A test with adhesives to promote the recovery of biological soil crusts Science.gov (United States) Ballesteros, M.; Ayerbe, J.; Casares, M.; Cañadas, E. M.; Lorite, J. 2017-04-01 The loss of biological soil crusts represents a challenge for the restoration of disturbed environments, specifically in particular substrates hosting unique lichen communities. However, the recovery of lichen species affected by mining is rarely addressed in restoration projects. Here, we evaluate the translocation of Diploschistes diacapsis, a representative species of gypsum lichen communities affected by quarrying. We tested how a selection of adhesives could improve thallus attachment to the substrate and affect lichen vitality (as CO2 exchange and fluorescence) in rainfall-simulation and field experiments. Treatments included: white glue, water, hydroseeding stabiliser, gum arabic, synthetic resin, and a control with no adhesive. Attachment differed only in the field, where white glue and water performed best. Adhesives altered CO2 exchange and fluorescence yield. Notably, wet spoils allowed thalli to bind to the substrate after drying, revealing as the most suitable option for translocation. The satisfactory results applying water on gypsum spoils are encouraging to test this methodology with other lichen species. Implementing these measures in restoration projects would be relatively easy and cost-effective. It would help not only to recover lichen species in the disturbed areas but also to take advantage of an extremely valuable biological material that otherwise would be lost. 19. Flue-gas desulfurization gypsum effects on urea-degrading bacteria and ammonia volatilization from broiler litter. Science.gov (United States) Burt, Christopher D; Cabrera, Miguel L; Rothrock, Michael J; Kissel, D E 2017-08-01 A major concern of the broiler industry is the volatilization of ammonia (NH3) from the mixture of bedding material and broiler excretion that covers the floor of broiler houses. Gypsum has been proposed as a litter amendment to reduce NH3 volatilization, but reports of NH3 abatement vary among studies and the mechanism responsible for decreasing NH3 volatilization is not well understood. The goal of this study was to evaluate the effect of adding 20 or 40% flue-gas desulfurization gypsum (FGDG) to broiler litter on pH, electrical conductivity (EC), water potential, urea-degrading bacteria abundance, NH3 and carbon dioxide (CO2) evolution, and nitrogen (N) mineralization in several 21-d experiments. The addition of FGDG to broiler litter increased EC by 24 to 33% (P mineralization by 10 to 11% (P = 0.0001) as compared to litters not amended with FGDG. Furthermore, the addition of FGDG to broiler litter decreased NH3 volatilization by 18 to 28% (P litter pH values compared to un-amended litter (P litter with 20% FGDG can decrease NH3 volatilization and increase the fertlizer value of broiler litter. © 2017 Poultry Science Association Inc. 20. Incorporation of gypsum waste in ceramic block production: Proposal for a minimal battery of tests to evaluate technical and environmental viability of this recycling process. Science.gov (United States) Godinho-Castro, Alcione P; Testolin, Renan C; Janke, Leandro; Corrêa, Albertina X R; Radetski, Claudemir M 2012-01-01 Civil engineering-related construction and demolition debris is an important source of waste disposed of in municipal solid waste landfills. After clay materials, gypsum waste is the second largest contributor to the residential construction waste stream. As demand for sustainable building practices grows, interest in recovering gypsum waste from construction and demolition debris is increasing, but there is a lack of standardized tests to evaluate the technical and environmental viability of this solid waste recycling process. By recycling gypsum waste, natural deposits of gypsum might be conserved and high amounts of the waste by-product could be reused in the civil construction industry. In this context, this paper investigates a physical property (i.e., resistance to axial compression), the chemical composition and the ecotoxicological potential of ceramic blocks constructed with different proportions of clay, cement and gypsum waste, and assesses the feasibility of using a minimal battery of tests to evaluate the viability of this recycling process. Consideration of the results for the resistance to axial compression tests together with production costs revealed that the best formulation was 35% of plastic clay, 35% of non-plastic clay, 10% of Portland cement and 20% of gypsum waste, which showed a mean resistance of 4.64MPa. Energy dispersive X-ray spectrometry showed calcium and sulfur to be the main elements, while quartz, gypsum, ettringite and nacrite were the main crystalline compounds found in this formulation. Ecotoxicity tests showed that leachate from this formulation is weakly toxic toward daphnids and bacteria (EC(20%)=69.0 and 75.0, respectively), while for algae and fish the leachate samples were not toxic at the EC(50%) level. Overall, these results show that the addition of 20% of gypsum waste to the ceramic blocks could provide a viable substitute for clay in the ceramics industry and the tests applied in this study proved to be a useful tool 1. Visualization of the structural changes in plywood and gypsum board during the growth of Chaetomium globosum and Stachybotrys chartarum DEFF Research Database (Denmark) Lewinska, Anna Malgorzata; Hoof, Jakob Blæsbjerg; Peuhkuri, Ruut H. 2016-01-01 of building materials such as plywood and gypsum wallboard. This study focuses on using micro-computed tomography (microCT) to investigate changes of the structure of plywood and gypsum wallboard during fungal degradation by S. chartarum and C. globosum. Changes in the materials as a result of dampness...... and fungal growth were determined by measuring porosity and pore shape via microCT. The results show that the composition of the building material influenced the level of penetration by fungi as shown by scanning electron microscopy (SEM). Plywood appeared to be the most affected, with the penetration... 2. Effect of gypsum, pressmud, fulvic acid and zinc sources on yield and zinc uptake by rice crop in a saline-sodic soil International Nuclear Information System (INIS) Chand, M. 1980-01-01 The application of fulvic acid to a saline-sodic soil augmented the solubility of zinc by thousands fold. Zinc fulvate when applied at levels equivalent to that of zinc sulphate was more effective in enhancing diffusion of zinc in the soil. Application of gypsum, zinc sulphate and fulvic acid significantly increased dry matter yield and uptake of zinc by rice crop in a saline-sodic soil. Application of gypsum with pressmud or with fulvic acid and zinc sulphate resulted in significantly higher yield and zinc uptake than in other treatments. (orig.) 3. Filler de grafito reciclado de EDM en pastas de yeso = EDM recycled graphite filler in gypsum pastes Directory of Open Access Journals (Sweden) Nelson Flores 2017-08-01 Full Text Available El grafito puede obtenerse de forma natural o sintética, pero este último se ha utilizado en carreteras debido a su dureza, así como en placas de cerámica fina. Se demuestran las posibilidades de la adición del polvo de grafito isostático procedente del fresado de moldes fabricados por Electroerosión de Penetración (EDM en compuestos a base de yeso. Para ello se prepararon mezclas de yeso industrial con adiciones en porcentajes diferentes de grafito EDM para evaluar las propiedades físicas y mecánicas, caracterizando previamente ambos materiales. El yeso fue sustituido por grafito en cinco fracciones diferentes, 5, 10, 15, 20 y 25%, en peso, en la preparación de las mezclas. En la designación Y-0.7G-0 y Y-0.6G-0 de las series de probetas prismáticas de 40x40x160mm, la letra Y se refiere al yeso y G significa grafito (G-0 probetas patrón sin grafito, con relaciones agua/yeso (a/y 0,7 y 0,6. Después del análisis de los resultados obtenidos, se realizó unas nuevas series con la adición de plastificante y también con mayor cantidad de grafito, 25 a 50% en peso y otras relaciones a/y basadas en su trabajabilidad, para verificar la incidencia en la resistencia a flexión y compresión. Abstract Graphite can be obtained naturally or synthetically, but the latter has been used on roads because of its hardness, as well as in thin ceramic plates. The possibilities of the addition of the isostatic graphite powder from the milling of molds made by EDM in gypsum-based compounds are demonstrated. For this purpose mixtures of industrial gypsum with additions in different percentages of EDM graphite were prepared to evaluate the physical and mechanical properties, previously characterizing both materials. The gypsum was replaced by graphite in five different fractions, 5, 10, 15, 20 and 25% by weight, in the preparation of the mixtures. In the designation Y-0.7G-0 and Y-0.6G-0 of the series of prismatic specimens of 40x40x160mm, the letter Y 4. Efficacy of S-flurbiprofen plaster in knee osteoarthritis treatment: Results from a phase III, randomized, active-controlled, adequate, and well-controlled trial. Science.gov (United States) Yataba, Ikuko; Otsuka, Noboru; Matsushita, Isao; Matsumoto, Hideo; Hoshino, Yuichi 2017-01-01 S-flurbiprofen plaster (SFPP) is a novel non-steroidal anti-inflammatory drug (NSAID) patch, intended for topical treatment for musculoskeletal diseases. This trial was conducted to examine the effectiveness of SFPP using active comparator, flurbiprofen (FP) patch, on knee osteoarthritis (OA) symptoms. This was a phase III, multi-center, randomized, adequate, and well-controlled trial, both investigators and patients were blinded to the assigned treatment. Enrolled 633 knee OA patients were treated with either SFPP or FP patch for two weeks. The primary endpoint was improvement in knee pain on rising from the chair as assessed by visual analogue scale (rVAS). Safety was evaluated through adverse events (AEs). The change in rVAS was 40.9 mm in SFPP group and 30.6 mm in FP patch group (p < 0.001). The incidence of drug-related AEs at the application site was 9.5% (32 AEs, 29 mild and 3 moderate) in SFPP and 1.6% in FP patch (p < 0.001). Withdrawals due to AE were five in SFPP and one in FP patch. The superiority of SFPP in efficacy was demonstrated. Most of AEs were mild and few AEs led to treatment discontinuation. Therefore, SFPP provides an additional option for knee OA therapy. 5. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine Science.gov (United States) Muirhead, Dean; Carrier, Christopher 2012-01-01 In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines 6. Geomorphological Evidence of Plausible Water Activity and Evaporatic Deposition in Interdune Areas of the Gypsum-rich Olympia Undae Dune Field Science.gov (United States) Szynkiewicz, A.; Ewing, R. C.; Fishbaugh, K. E.; Bourke, M. C.; Bustos, D.; Pratt, L. M. 2009-03-01 New morphological features (e.g., cross-bedding strata, bright patches), revealed by HiRISE for the gypsum-rich Olympia Undae Dune Field, appear to indicate the change(s) in paleoenvironmental conditions likely controlled by climate fluctuations in the North Pole of Mars. 7. Gypsum (CaSO4·2H2O) Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis Science.gov (United States) Chen, Si Cong; Su, Jincai; Fu, Feng-Jiang; Mi, Baoxia; Chung, Tai-Shung 2013-01-01 We have examined the gypsum (CaSO4·2H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. PMID:24957062 8. A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum Directory of Open Access Journals (Sweden) Vanessa Rheinheimer 2016-08-01 Full Text Available This paper shows the microstructural differences and phase characterization of pure phases and hydrated products of the cubic and orthorhombic (Na-doped polymorphs of tricalcium aluminate (C3A, which are commonly found in traditional Portland cements. Pure, anhydrous samples were characterized using scanning transmission X-ray microscopy (STXM, X-ray photoelectron spectroscopy (XPS and X-ray diffraction (XRD and demonstrated differences in the chemical and mineralogical composition as well as the morphology on a micro/nano-scale. C3A/gypsum blends with mass ratios of 0.2 and 1.9 were hydrated using a water/C3A ratio of 1.2, and the products obtained after three days were assessed using STXM. The hydration process and subsequent formation of calcium sulfate in the C3A/gypsum systems were identified through the changes in the LIII edge fine structure for Calcium. The results also show greater Ca LII binding energies between hydrated samples with different gypsum contents. Conversely, the hydrated samples from the cubic and orthorhombic C3A at the same amount of gypsum exhibited strong morphological differences but similar chemical environments. 9. Land subsidence and caprock dolines caused by subsurface gypsum dissolution and the effect of subsidence on the fluvial system in the Upper Tigris Basin (between Bismil Batman, Turkey) Science.gov (United States) Doğan, Uğur 2005-11-01 Karstification-based land subsidence was found in the Upper Tigris Basin with dimensions not seen anywhere else in Turkey. The area of land subsidence, where there are secondary and tertiary subsidence developments, reaches 140 km 2. Subsidence depth ranges between 40 and 70 m. The subsidence was formed as a result of subsurface gypsum dissolution in Lower Miocene formation. Although there are limestones together with gypsum and Eocene limestone below them in the area, a subsidence with such a large area is indicative of karstification in the gypsum. The stratigraphical cross-sections taken from the wells and the water analyses also verify this fact. The Lower Miocene gypsum, which shows confined aquifer features, was completely dissolved by the aggressive waters injected from the top and discharged through by Zellek Fault. This resulted in the development of subsidence and formation of caprock dolines on loosely textured Upper Miocene-Pliocene cover formations. The Tigris River runs through the subsidence area between Batman and Bismil. There are four terrace levels as T1 (40 m), T2 (30 m), T3 (10 m) and T4 (4-5 m) in the Tigris River valley. It was also found that there were some movements of the levels of the terraces in the valley by subsidence. The subsidence developed gradually throughout the Quaternary; however no terrace was formed purely because of subsidence. 10. Ultrasonically nebulised electrolysed oxidising water: a promising new infection control programme for impressions, metals and gypsum casts used in dental hospitals. Science.gov (United States) Wu, G; Yu, X; Gu, Z 2008-04-01 Controlling the transmission of infectious diseases by impressions, metals and dental casts in dental hospitals remains a challenge. Current disinfection methods have various drawbacks. This study introduced and provided a preliminary evaluation of the feasibility of using ultrasonically nebulised, electrolysed oxidising water (UNEOW) as a new infection control programme. UNEOW was produced from freshly generated electrolysed oxidising water (EOW). Samples of impressions, titanium and gypsum were subjected to the following treatments: (1) immersion in 1% sodium hypochlorite for 10min; (2) immersion in EOW for 10min; (3) exposure to UNEOW for 15, 30 and 45min; (4) no disinfection (control). Bactericidal efficacy was examined using Staphylococcus aureus and Bacillus subtilis var. niger spores as indicators. Dimensional accuracy, surface quality, and effect of corrosion were also evaluated for the different samples. Results showed that except for B. subtilis var. niger spores on gypsum casts, the bacterial reduction log(10) values after 30-45min treatment with UNEOW were all above 4. The impression dimensional changes showed no difference between control and UNEOW groups, but both were significantly lower than the EOW and sodium hypochlorite groups (Pimpressions and gypsum casts. No assessable corrosion was found on the titanium surface after a 45min treatment with UNEOW. The findings indicated that use of UNEOW is a feasible and promising approach for controlling the transmission of infectious diseases by impressions, gypsum casts and denture metals in dental facilities. 11. A low-temperature ductile shear zone: The gypsum-dominated western extension of the brittle Fella-Sava Fault, Southern Alps. Science.gov (United States) Bartel, Esther Maria; Neubauer, Franz; Heberer, Bianca; Genser, Johann 2014-12-01 Based on structural and fabric analyses at variable scales we investigate the evaporitic gypsum-dominated Comeglians-Paularo shear zone in the Southern Alps (Friuli). It represents the lateral western termination of the brittle Fella-Sava Fault. Missing dehydration products of gypsum and the lack of annealing indicate temperatures below 100 °C during development of the shear zone. Despite of such low temperatures the shear zone clearly exhibits mylonitic flow, thus evidencing laterally coeval activity of brittle and viscous deformation. The dominant structures within the gypsum rocks of the Lower Bellerophon Formation are a steeply to gently S-dipping foliation, a subhorizontal stretching lineation and pure shear-dominated porphyroclast systems. A subordinate simple shear component with dextral displacement is indicated by scattered σ-clasts. Both meso- and microscale structures are characteristic of a subsimple shear type of deformation with components of both coaxial and non-coaxial strain. Shortening in a transpressive regime was accommodated by right-lateral displacement and internal pure shear deformation within the Comeglians-Paularo shear zone. The shear zone shows evidence for a combination of two stretching faults, where stretching occurred in the rheologically weaker gypsum member and brittle behavior in enveloping lithologies. 12. Effect of Organic Matter and Gypsum Powder Some Traits of Maize in a Saline-Sodic Soil Directory of Open Access Journals (Sweden) M Khotabaee 2015-04-01 Full Text Available Saline-sodic soils have improper physical, chemical and biological condition and the crop productivity is low in these conditions. Application of conditioners often can be a proper solution for reclamation and improving the productivity of saline-sodic soils. In order to study the effect of some conditioners on soil chemical characteristics and yield of maize (SC260 cultivar in a saline-sodic soil, an experiment was carried out as a completely randomized design with 3 replications in a research greenhouse of Ferdowsi university of Mashhad. The studied treatments included control and 10 ton/ha of compost (MC, vermi-compost (VC, poultry manure (PM, and gypsum powder (G. The results showed that poultry manure and vemi-compost treatments increased significantly (p 13. The study of Influencing Maintenance Factors on Failures of Two gypsum Kilns by Failure Modes and Effects Analysis (FMEA Directory of Open Access Journals (Sweden) Iraj Alimohammadi 2014-06-01 Full Text Available Developing technology and using equipment in Iranian industries caused that maintenance system would be more important to use. Using proper management techniques not only increase the performance of production system but also reduce the failures and costs. The aim of this study was to determine the quality of maintenance system and the effects of its components on failures of kilns in two gypsum production companies using Failure Modes and Effects Analysis (FMEA. Furthermore the costs of failures were studied. After the study of gypsum production steps in the factories, FMEA was conducted by the determination of analysis insight, information gathering, making list of kilns’ component and filling up the FMEA’s tables. The effects of failures on production, how to fail, failure rate, failure severity, and control measures were studied. The evaluation of maintenance system was studied by a check list including questions related to system components. The costs of failures were determined by refer in accounting notebooks and interview with the head of accounting department. It was found the total qualities of maintenance system in NO.1 was more than NO.2 but because of lower quality of NO.1’s kiln design, number of failures and their costs were more. In addition it was determined that repair costs in NO.2’s kiln were about one third of NO.1’s. The low severity failures caused the most costs in comparison to the moderate and low ones. The technical characteristics of kilns were appeared to be the most important factors in reducing of failures and costs. 14. Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique. Science.gov (United States) Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Ji-Hwan; Kim, Hae-Young 2014-03-01 This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of inter-examiner and inter-method variability. The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models. 15. Evolution characteristic of gypsum-salt rocks of the upper member of Oligocene Lower Ganchaigou Fm in the Shizigou area, western Qaidam Basin Directory of Open Access Journals (Sweden) Dinghong Yi 2017-09-01 Full Text Available Over years of oil and gas exploration in the Qaidam Basin, reservoirs have been discovered in many layers. In the Shizigou area, western Qaidam Basin, the upper member of Oligocene Lower Ganchaigou Fm is an important target for oil and gas exploration, and gypsum-salt rocks are the high-quality caprocks for the preservation of oil and gas reservoirs in this area. For predicting oil and gas exploration direction and target in the western Qaidam Basin and providing guidance for its oil and gas exploration deployment, its depositional characteristics and environment of gypsum-salt rocks in this area were investigated based on the core observation, thin section identification, and analysis of grain size, sensitivity parameter ratios (Sr/Cu, Fe/Mn, (Fe + Al/(Ca + Mg, V/(V + Ni and Pr/Ph, pyrite content and inclusions. The following characteristics are identified. First, gypsum-salt rocks are mainly distributed in the depocenter of the lake basin and their thickness decreases towards the margin of the basin. They are laterally transformed into carbonate rocks or terrigenous clastic rocks. They are areally distributed in the shape of irregular ellipse. Second, gypsum-salt rocks are vertically developed mainly in the middle and upper parts of the upper member of Lower Ganchaigou Fm and they are interbedded with carbonate rocks or terrigenous clastic rocks. Their single layer thickness changes greatly, and there are many layers with good continuity. Third, Sand Group III to Group I in the upper member of Lower Ganchaigou Fm (inter-salt are of reductive water environment of semi-deep to deep lake facies due to their sedimentation in an arid and hot climate. It is concluded that gypsum-salt rocks of the upper member of Lower Ganchaigou Fm are distributed widely with great accumulative thickness in this area; and that they are originated from deep lake water by virtue of evaporation, concentration and crystallization in an arid and hot climate instead 16. Preliminary U-Th Dating of Endogenic Gypsum From Lake Petén-Itzá, Guatemala Science.gov (United States) Gamble, V. C.; Gallup, C. D.; Hodell, D.; Anselmetti, F.; Brenner, M.; Ariztegui, D. 2007-05-01 Uranium-thorium dating of lake sediments can provide accurate ages beyond the range of radiocarbon dating. Many lakes have endogenic precipitation of calcium bearing minerals that allow for substitution by uranium within their crystal structures. The water chemistry of Lake Petén-Itzá, located in northern Guatemala, is dominated by calcium, sulfate and carbonate ions (Deevey et al. 1980; Curtis et al. 1998). Changes in regional climate due to suspected shifts in the ITCZ over the past 85,000 years resulted in both calcite and gypsum deposition, especially during drier periods (Hodell et al. 2006). Both precipitates incorporate uranium from the lake water and can be used for U-Th dating. U-Th dating is problematic in lake systems for several reasons: the potential for 1) diagenetic alteration or dissolution while the endogenic precipitates are settling and after deposition and 2) contamination by detrital thorium. Contamination is a primary issue because of the difficulty of separating the precipitates from the sediment. Despite these concerns, U-Th dating of lake sediments has the potential to be successful with careful selection of precipitates and thorough analysis of the precipitate, the lake system, and the diagenetic environment. Preliminary samples of Lake Petén-Itzá gypsum contain euhedral crystals, indicating a lack of post-depositional alteration. However, the samples have high background thorium levels, indicating the necessity of using the U-Th total sample dissolution isochron dating method (as described by Ku, 2000) to quantify authigenic thorium. Curtis J.H., Brenner M., Hodell D.A., Balser R.A., Islebe G.A., Hooghiemstra H. 1998. A multi-proxy study of Holocene environmental change in the Maya lowlands of Petén, Guatemala. Journal of Paleolimnology 19, 139-159. Deevey E.S., Brenner M., Flannery M.S., Yezdani G.H. 1980. Lakes Yaxha and Scanab, Petén, Guatemala: Limnology and hydrology. Arch. Hydrobiol. 57, 419-460. Hodell D.A., Anselmetti F 17. Recovery of soil physical properties by green manure, liming, gypsum and pasture and spontaneous native species¹ Directory of Open Access Journals (Sweden) Carolina dos Santos Batista Bonini 2011-08-01 Full Text Available Inadequate usage can degrade natural resources, particularly soils. More attention has been paid to practices aiming at the recovery of degraded soils in the last years, e.g, the use of organic fertilizers, liming and introduction of species adapted to adverse conditions. The purpose of this study was therefore to investigate the recovery of physical properties of a Red Latosol (Oxisol degraded by the construction of a hydroelectric power station. In the study area, a soil layer about 8m thick had been withdrawn by heavy machines leading not only to soil compaction, but resulting in high-degree degradation. The experiment was arranged in a completely randomized design with nine treatments and four replications. The treatments consisted of: 1- soil mobilization by tilling (to ensure the effect of mechanical mobilization in all treatments without planting, but growth of spontaneous vegetation; 2- Black velvet bean (Stizolobium aterrimum Piper & Tracy; 3- Pigeonpea (Cajanus cajan (L. DC; 4- Liming + black velvet bean; 5-Liming + pigeonpea until 1994, when replaced by jack bean (Canavalia ensiformis; 6- Liming + gypsum + black velvet bean; 7- Liming + gypsum + pigeonpea until 1994, when replaced by jack bean; and two controls as reference: 8- Native Cerrado vegetation and 9- bare soil (no tilling and no planting, left under natural conditions and in this situation, without spontaneous vegetation. In treatments 1 through 7, the soil was tilled. Treatments were installed in 1992 and left unmanaged for seven years, until brachiaria (Brachiaria decumbens was planted in all plots in 1999. Seventeen years after implantation, the properties soil macroporosity, microporosity, total porosity, bulk density and aggregate stability were assessed in the previously described treatments in the soil layers 0.00-0.10; 0.10-0.20 and 0.20-0.40 m, and soil Penetration Resistance and soil moisture in 0.00-0.15 and 0.15-0.30 m. The plants were evaluated for: brachiaria 18. Characterization of mudejar mortars from St. Gil Abbot church (Zaragoza, Spain: Investigation of the manufacturing technology of ancient gypsum mortars Directory of Open Access Journals (Sweden) Igea, J. 2012-12-01 Full Text Available This work has been focused on the investigation of the technological procedure of Mudejar mortars applied to the characterization of a group of unaltered samples from an example church of Mudejar architecture of Aragon. The research was carried out using multi-analytical techniques including petrographic study, chemistry and mineralogical analysis. All mortars present a homogeneous composition. The binder is made up of a mixture of gypsum and a very low proportion of lime, while the main components of the aggregate are gypsum and carbonate rock fragments, both in a different thermal state of decomposition. The results have proved that both, binder and aggregates display the same composition in these mortars. These aggregates are the by-product of a grinding process of the previously burnt raw materials which have had a positive influence on the properties of the mortars in improving their quality. Este trabajo se ha centrado en la investigación de la tecnología de fabricación de morteros mudéjares mediante la caracterización de un conjunto de muestras inalteradas procedentes de una iglesia representativa de la arquitectura Mudéjar aragonesa. La investigación se llevó a cabo mediante el uso combinado de técnicas analíticas incluyendo el estudio petrográfico y el análisis químico y mineralógico. Todos los morteros presentan una composición constante formada por una mezcla de yeso y cal, en muy baja proporción, como ligante, mientras que el árido está formado por fragmentos de rocas yesíferas y carbonatadas en distinto estado de descomposición térmica. Los resultados confirman que en la fabricación de los morteros, ligante y áridos presentan la misma composición, siendo éstos últimos el subproducto de la misma materia prima calcinada, incorporados para elaborar el mortero, tras un proceso de molienda. Esta característica ha influido positivamente en las propiedades de los morteros, mejorando su calidad. 19. Evaluation of surface detail reproduction, dimensional stability and gypsum compatibility of monophase polyvinyl-siloxane and polyether elastomeric impression materials under dry and moist conditions. Science.gov (United States) Vadapalli, Sriharsha Babu; Atluri, Kaleswararao; Putcha, Madhu Sudhan; Kondreddi, Sirisha; Kumar, N Suman; Tadi, Durga Prasad 2016-01-01 This in vitro study was designed to compare polyvinyl-siloxane (PVS) monophase and polyether (PE) monophase materials under dry and moist conditions for properties such as surface detail reproduction, dimensional stability, and gypsum compatibility. Surface detail reproduction was evaluated using two criteria. Dimensional stability was evaluated according to American Dental Association (ADA) specification no. 19. Gypsum compatibility was assessed by two criteria. All the samples were evaluated, and the data obtained were analyzed by a two-way analysis of variance (ANOVA) and Pearson's Chi-square tests. When surface detail reproduction was evaluated with modification of ADA specification no. 19, both the groups under the two conditions showed no significant difference statistically. When evaluated macroscopically both the groups showed statistically significant difference. Results for dimensional stability showed that the deviation from standard was significant among the two groups, where Aquasil group showed significantly more deviation compared to Impregum group (P < 0.001). Two conditions also showed significant difference, with moist conditions showing significantly more deviation compared to dry condition (P < 0.001). The results of gypsum compatibility when evaluated with modification of ADA specification no. 19 and by giving grades to the casts for both the groups and under two conditions showed no significant difference statistically. Regarding dimensional stability, both impregum and aquasil performed better in dry condition than in moist; impregum performed better than aquasil in both the conditions. When tested for surface detail reproduction according to ADA specification, under dry and moist conditions both of them performed almost equally. When tested according to macroscopic evaluation, impregum and aquasil performed significantly better in dry condition compared to moist condition. In dry condition, both the materials performed almost equally. In 20. A cone-beam computed tomography triple scan procedure to obtain a three-dimensional augmented virtual skull model appropriate for orthognathic surgery planning. NARCIS (Netherlands) Swennen, G.R.J.; Mollemans, W.; Clercq, C. De; Abeloos, J.V.S.; Lamoral, P.; Lippens, F.R.C.; Neyt, N.; Casselman, J.W.; Schutyser, F.A.C. 2009-01-01 The aim of this study was to present a new approach to acquire a three-dimensional virtual skull model appropriate for orthognathic surgery planning without the use of plaster dental models and without deformation of the facial soft-tissue mask. A "triple" cone-beam computed tomography (CBCT) scan 1. Corrosion behaviour of metallic and non-metallic materials in various media in the Anhydrite and Gypsum Mine Felsenau/AG International Nuclear Information System (INIS) Laske, D.; Wiedemann, K.H. 1983-10-01 The final underground disposal of radioactive wastes necessitates container materials with a good long-term resistance against corrosion from both external agents and the solidification matrix inside. For low- and medium-level active waste, repositories in anhydrite sites, among others, are under consideration. Sheet and plate samples from 14 metallic and 8 non-metallic materials have been tested for 5 years in a tunnel in the Anhydrite and Gypsum Mine Felsenau/AG for their corrosion resistance in the tunnel atmosphere, anhydrite powder, gypsum powder, gypsum, and cement. From the metallic materials tested, only chromium-nickel steel is corrosion resistant to all the media present. Zinc plated and tin plated iron sheet as well as aluminium and aluminium alloys are corrosion resistant only in the atmosphere of the tunnel, and lead plated iron sheet is resistant also in cement. Aluminium is dissolved in cement. Uncovered iron sheet undergoes severe corrosion. The non-metallic coatings tested (lacquer, stove lacquer, or synthetic resins) partially flake off already after one year's testing and are therefore not appropriate for iron sheet corrosion protection. No influence of the different media has been observed after 5 years on the 8 plastic materials tested (6 without, and 2 with glass fiber reinforcement). (author) 2. Measurements of local mass transfer coefficient of Flow Accelerated Corrosion at feeder outlet pipes in CANDU using Plaster of Paris method International Nuclear Information System (INIS) Hyuk Kwon; Dong Un Seo; Goon-Cherl Park 2005-01-01 Full text of publication follows: Flow Accelerated Corrosion (FAC) is a corrosion mechanism that results in wall thinning in piping systems and components. FAC on carbon steels in pure water has occurred in a number of industry and power plant. A pipe wall thinning due to the FAC at nuclear power plant is just reported in confined to carbon steel pipe on the secondary system which does not equip a radioactive component. Recently, at Canadian Deuterium Uranium type reactor, it is reported that the feeder lines suffer the wall thinning on the primary system to equip 380 feeder pipes. Differently from the fast FAC rate of the secondary system on PWR, FAC rate of feeder pipes on CANDU is not more than the 0.2 mm/year. Although the FAC rate of feeder pipe is relatively slow, the narrow thickness margin of 2.6089 mm is endangered sufficiently by only the slow FAC rate. The FAC is governed by the mass transfer coefficient which is determined by the flow field. To well predict the FAC rate, mass transfer coefficient should be well measured or calculated. New measurement method of mass transfer coefficient is developed to obtain the coefficient for the complex shape like feeder pipe. The method evaluated the naphthalene sublimation method to apply it under the water flow. The naphthalene sublimation method can be used to study mass and heat transfer with confidence for a variety of applications, but with certain restrictions. At present, Plaster of paris method can modified the sublimation method to overcome the restrictions. This method is particularly useful in complex flows on geometries and for flows with large gradients in wall transport rate. The test specimen can be easily prepared by several methods, including dipping, machining, spraying, and casting. The local transfer coefficients can be determined with high accuracy and in detail by automated measurement systems that eliminate most human errors during the measurement process. To evaluate the method, the 3. Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis Science.gov (United States) Culka, Adam; Osterrothová, Kateřina; Hutchinson, Ian; Ingley, Richard; McHugh, Melissa; Oren, Aharon; Edwards, Howell G. M.; Jehlička, Jan 2014-01-01 A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved. PMID:25368354 4. Arsenic leaching and speciation in C&D debris landfills and the relationship with gypsum drywall content. Science.gov (United States) Zhang, Jianye; Kim, Hwidong; Dubey, Brajesh; Townsend, Timothy 2017-01-01 The effects of sulfide levels on arsenic leaching and speciation were investigated using leachate generated from laboratory-scale construction and demolition (C&D) debris landfills, which were simulated lysimeters containing various percentages of gypsum drywall. The drywall percentages in lysimeters were 0, 1, 6, and 12.4wt% (weight percent) respectively. With the exception of a control lysimeter that contained 12.4wt% of drywall, each lysimeter contained chromated copper arsenate (CCA) treated wood, which accounts for 10wt% of the C&D waste. During the period of study, lysimeters were mostly under anaerobic conditions. Leachate analysis results showed that sulfide levels increased as the percentage of drywall increased in landfills, but arsenic concentrations in leachate were not linearly correlated with sulfide levels. Instead, the arsenic concentrations decreased as sulfide increased up to approximately 1000μg/L, but had an increase with further increase in sulfide levels, forming a V-shape on the arsenic vs. sulfide plot. The analysis of arsenic speciation in leachate showed different species distribution as sulfide levels changed; the fraction of arsenite (As(III)) increased as the sulfide level increased, and thioarsenate anions (As(V)) were detected when the sulfide level further increased (>10 4 μg/L). The formation of insoluble arsenic sulfide minerals at a lower range of sulfide and soluble thioarsenic anionic species at a higher range of sulfide likely contributed to the decreasing and increasing trend of arsenic leaching. Copyright © 2016. Published by Elsevier Ltd. 5. Analytical results, geology, and sample locality map of mercury-sulfur-gypsum mineralization at Crater, Inyo County, California Science.gov (United States) Erickson, M.S.; Marsh, S.P.; Roemer, T.A. 1984-01-01 The Crater mercury-su l fur-gypsum ~ineral ized area is located in east-central California along the crest of the Last Chance Range, west of the north end of Death Valley (fig. 1). The area is in the northwest quarter of the Last Chance Range 15-minute quadrangle and occupies the area between 117 39 and 117 45 longitude and 37 10 and 37 15 latitudP.. The area studied lies between 5000 ( 1525 m) and 6000 ( 1830 m) feet above sea level. Relief isgenerally moderate but can be extreme in some places, as at Hanging Rock Canyon (plate 1). The climate is arid, and there are no active streams in the area. The range fronts east and west of the area are precipitous and incised by many steep canyons, whereas the range crest has relatively low relief. The old abandoned town and mine site of Crater 1 ie in this area of low relief. Access to the Crater area is by paved and dirt roads from Big Pine to the west or from the north end of the Death Valley National Monument to the southeast. 6. Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis. Science.gov (United States) Culka, Adam; Osterrothová, Kateřina; Hutchinson, Ian; Ingley, Richard; McHugh, Melissa; Oren, Aharon; Edwards, Howell G M; Jehlička, Jan 2014-12-13 A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved. © 2014 The Author(s) Published by the Royal Society. All rights reserved. 7. Fabrication of calcite blocks from gypsum blocks by compositional transformation based on dissolution-precipitation reactions in sodium carbonate solution. Science.gov (United States) Ishikawa, Kunio; Kawachi, Giichiro; Tsuru, Kanji; Yoshimoto, Ayami 2017-03-01 Calcium carbonate (CaCO 3 ) has been used as a bone substitute, and is a precursor for carbonate apatite, which is also a promising bone substitute. However, limited studies have been reported on the fabrication of artificial calcite blocks. In the present study, cylindrical calcite blocks (ϕ6×3mm) were fabricated by compositional transformation based on dissolution-precipitation reactions using different calcium sulfate blocks as a precursor. In the dissolution-precipitation reactions, both CaSO 4 ·2H 2 O and CaSO 4 transformed into calcite, a polymorph of CaCO 3 , while maintaining their macroscopic structure when immersed in 1mol/L Na 2 CO 3 solution at 80°C for 1week. The diametral tensile strengths of the calcite blocks formed using CaSO 4 ·2H 2 O and CaSO 4 were 1.0±0.3 and 2.3±0.7MPa, respectively. The fabrication of calcite blocks using CaSO 4 ·2H 2 O and CaSO 4 proposed in this investigation may be a useful method to produce calcite blocks because of the self-setting ability and high temperature stability of gypsum precursors. Copyright © 2016 Elsevier B.V. All rights reserved. 8. Richness, diversity and evenness of vegetation upon rehabilitation of gypsum mine spoiled lands in the Indian arid zone Science.gov (United States) Kumar, S.; Sharma, K.D.; Sharma, U.K.; Gough, L.P. 1998-01-01 Richness, diversity and evenness of vegetation, after rehabilitation of gypsum mine spoils at Barmer were investigated in plots protected and planted one year and four years ago. There were four water harvesting treatments, viz., half-moon terraces, micro-catchments with 5% slope, ridge and furrow and control, wherein, indigenous and exotic trees and shrubs were planted at 5 ?? 5 m spacing. Sampling of the planted and natural vegetation, using quadrats and transacts, revealed much less species richness in unplanted control as compared to all treatments and in all the years. The species richness that increased initially (within one year) gradually declined over time (during four year), though the extent varied in different treatments. The water harvesting treatment showing maximum initial increase in richness also showed maximum decline over time, though decline was more in annual species. Two perennial species increased in richness with time. This was further proved from the trends in diversity and evenness indices. It was concluded that natural successional process was accelerated by rehabilitation providing stability to the habitat. 9. Orthognathic model surgery with LEGO key-spacer. Science.gov (United States) Tsang, Alfred Chee-Ching; Lee, Alfred Siu Hong; Li, Wai Keung 2013-12-01 A new technique of model surgery using LEGO plates as key-spacers is described. This technique requires less time to set up compared with the conventional plaster model method. It also retains the preoperative setup with the same set of models. Movement of the segments can be measured and examined in detail with LEGO key-spacers. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved. 10. Manufacturing of mortars and concretes non-traditionals, by Portland cement, metakaoline and gypsum (15.05% Directory of Open Access Journals (Sweden) Talero, R. 1999-12-01 Full Text Available In a thorough previous research (1, it appeared that creation, evolution and development of the values of compressive mechanical strength (CS and flexural strength (FS, measured in specimens 1x1x6cm of mortar type ASTM C 452-68 (2, manufactured by ordinary Portland cement P-1 (14.11% C3A or PY-6 (0.00% C3A, metakaolin and gypsum (CaSO4∙2H2O -or ternary cements, CT-, were similar to the ones commonly developed in mortars and concretes of OPC. This paper sets up the experimental results obtained from non-traditional mortars and concretes prepared with such ternary cements -TC-, being the portland cement/metakaolin mass ratio, as follows: 80/20, 70/30 and 60/40. Finally, the behaviour of these cements against gypsum attack, has been also determined, using the following parameters: increase in length (ΔL%, compressive, CS, and flexural, FS, strengths, and ultrasound energy, UE. Experimental results obtained from these non-traditional mortars and concretes, show an increase in length (ΔL, in CS and FS, and in UE values, when there is addition of metakaolin. En una exhaustiva investigación anterior (1, se pudo comprobar que la creación, evolución y desarrollo de los valores de resistencias mecánicas a compresión, RMC, y flexotracción, RMF, proporcionados por probetas de 1x1x6 cm, de mortero 1:2,75, selenitoso tipo ASTM C 452-68 (2 -que habían sido preparadas con arena de Ottawa, cemento portland, P-1 (14,11% C3A o PY- 6 (0,00% C3A, metacaolín y yeso (CaSO4∙2H2O-, fue semejante a la que, comúnmente, desarrollan los morteros y hormigones tradicionales de cemento portland. En el presente trabajo se exponen los resultados experimentales obtenidos de morteros y hormigones no tradicionales, preparados con dichos cementos ternarios, CT, siendo las proporciones porcentuales en masa ensayadas, cemento portland/metacaolín, las siguientes: 80/20, 70 11. Microbial diversity in the deep-subsurface hydrothermal aquifer feeding the giant gypsum crystal-bearing Naica mine, Mexico Directory of Open Access Journals (Sweden) Marie eRagon 2013-03-01 Full Text Available The Naica mine in Northern Mexico is famous for its giant gypsum crystals, which may reach up to 11 m long and contain fluid inclusions that might have captured microorganisms during their formation. These crystals formed under particularly stable geochemical conditions in cavities filled by low salinity hydrothermal water at 54-58°C. We have explored the microbial diversity associated to these deep, saline hydrothermal waters collected in the deepest (ca. 700-760 m mineshafts by amplifying, cloning and sequencing small-subunit ribosomal RNA genes using primers specific for archaea, bacteria and eukaryotes. Eukaryotes were not detectable in the samples and the prokaryotic diversity identified was very low. Two archaeal operational taxonomic units (OTUs were detected in one sample. They clustered with, respectively, basal Thaumarchaeota lineages and with a large clade of environmental sequences branching at the base of the Thermoplasmatales within the Euryarchaeota. Bacterial sequences belonged to the Candidate Division OP3, Firmicutes and the Alpha- and Beta-Proteobacteria. Most of the lineages detected appear autochthonous to the Naica system, since they had as closest representatives environmental sequences retrieved from deep sediments or the deep subsurface. In addition, the high GC content of 16S rRNA gene sequences belonging to the archaea and to some OP3 OTUs suggests that at least these lineages are thermophilic. Attempts to amplify diagnostic functional genes for methanogenesis (mcrA and sulfate reduction (dsrAB were unsuccessful, suggesting that those activities, if present, are not important in the aquifer. By contrast, genes encoding archaeal ammonium monooxygenase (AamoA were amplified, suggesting that Naica Thaumarchaeota are involved in nitrification. These organisms are likely thermophilic chemolithoautotrophs adapted to thrive in an extremely energy-limited environment. 12. Seismic testing of a three-hour fire-rated steel-framed gypsum drywall partition for nuclear plants International Nuclear Information System (INIS) Thulin, F.A. Jr. 1983-01-01 The test specimen measured 1.22 by 3.05 m and consisted of three layers of 12.7 mm SHEETROCK Brand FIRECODE 'C' Gypsum Panels screw-attached to both sides of USG Steel 35SJ18 Studs 610 mm on centers. The specimen was first mounted in the earthquake simulator with the studs oriented horizontally and the runners vertically. Each runner was secured to a shaker support through which horizontal sinusoidal movement was induced normal to the surface of the wall. The damping ratio was found to be 9%. The average dynamic EI of the panel was 177000 GNxmm 2 . After the OBE scans, the specimen withstood the SSE scan for frequencies between 4 and 25 Hz. Resonance occured at 9 Hz. With a support acceleration of 3.0 gsub(e), the midspan acceleration reached 6.83 gsub(e). The same specimen was rotated 90 0 to a horizontal position with each runner attached to the corresponding shaker support which induced sinusoidal motion parallel to the runners. In the SSE shake at a frequency of 9 Hz and a support acceleration of 3.0 gsub(e), the midspan acceleration reached 4.66 gsub(e). To confirm the structural integrity of the specimen, it was then mounted in a vacuum chamber and tested in accordance with ASTM E 72. The rollers were spaced at 2.98 m. The panel yielded at a uniform load of 20.8 kN (equivalent to force at 8.8 gsub(e) acceleration) and failed at 26.3 kN (11.1 gsub(e)); both values greater than the 6.83 gsub(e) maximum dynamic midspan acceleration. The average static EI was 136000 GNxmm 2 - close to the 177000 GNxmm 2 dynamic EI. This transverse load test showed that the specimen was not structurally damaged by the shaker tests simulating earthquakes in nuclear plants. (orig./HP) 13. Metals in Soil and Runoff from a Piedmont Hay Field Amended with Broiler Litter and Flue Gas Desulfurization Gypsum. Science.gov (United States) Schomberg, Harry H; Endale, Dinku M; Jenkins, Michael B; Chaney, Rufus L; Franklin, Dorcas H 2018-03-01 Flue gas desulfurization gypsum (FGDG) from coal-fired power plants is readily available for agricultural use in many US regions. Broiler litter (BL) provides plant available N, P, and K but can be a source of unwanted As, Cu, and Zn. As a source of Ca and S, FGDG can reduce losses of P and other elements in runoff from BL-amended areas. Rainfall simulation plots (2.0 m) were established on a Piedmont Cecil soil growing 'Coastal' bermudagrass ( L.) for hay. Accumulation and transport of As, Cu, Cd, Cr, Hg, Pb, and Zn were evaluated after annual BL applications (13.5 Mg ha) with four FGDG rates (0, 2.2, 4.5, 9.0 Mg ha) and two FGDG treatments (0 and 9 Mg ha) without BL. Runoff As concentrations were sixfold greater with BL than without ( ≤ 0.01) and were similar to BL with FGDG at 2.2, 4.5 or 9.0 Mg ha ( ≤ 0.10). Runoff concentrations of target elements did not increase where FGDG was applied alone. After three annual applications of FGDG and BL, soil concentrations of As, Cr, Pb, Hg, and Cu were well below levels of environmental concern. Our findings indicate that runoff losses of As from BL application are not reduced with FGDG but support other research indicating no identifiable environmental risks from FGDG beneficial use in agricultural systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc. 14. Microbial diversity in the deep-subsurface hydrothermal aquifer feeding the giant gypsum crystal-bearing Naica Mine, Mexico Science.gov (United States) Ragon, Marie; Van Driessche, Alexander E. S.; García-Ruíz, Juan M.; Moreira, David; López-García, Purificación 2013-01-01 The Naica Mine in northern Mexico is famous for its giant gypsum crystals, which may reach up to 11 m long and contain fluid inclusions that might have captured microorganisms during their formation. These crystals formed under particularly stable geochemical conditions in cavities filled by low salinity hydrothermal water at 54–58°C. We have explored the microbial diversity associated to these deep, saline hydrothermal waters collected in the deepest (ca. 700–760 m) mineshafts by amplifying, cloning and sequencing small-subunit ribosomal RNA genes using primers specific for archaea, bacteria, and eukaryotes. Eukaryotes were not detectable in the samples and the prokaryotic diversity identified was very low. Two archaeal operational taxonomic units (OTUs) were detected in one sample. They clustered with, respectively, basal Thaumarchaeota lineages and with a large clade of environmental sequences branching at the base of the Thermoplasmatales within the Euryarchaeota. Bacterial sequences belonged to the Candidate Division OP3, Firmicutes and the Alpha- and Beta-proteobacteria. Most of the lineages detected appear autochthonous to the Naica system, since they had as closest representatives environmental sequences retrieved from deep sediments or the deep subsurface. In addition, the high GC content of 16S rRNA gene sequences belonging to the archaea and to some OP3 OTUs suggests that at least these lineages are thermophilic. Attempts to amplify diagnostic functional genes for methanogenesis (mcrA) and sulfate reduction (dsrAB) were unsuccessful, suggesting that those activities, if present, are not important in the aquifer. By contrast, genes encoding archaeal ammonium monooxygenase (AamoA) were amplified, suggesting that Naica Thaumarchaeota are involved in nitrification. These organisms are likely thermophilic chemolithoautotrophs adapted to thrive in an extremely energy-limited environment. PMID:23508882 15. Digital models: How can dental arch form be verified chairside? Directory of Open Access Journals (Sweden) Alana Tavares Full Text Available ABSTRACT Introduction: Plaster dental casts are routinely used during clinical practice to access maxillary dental arch form and assist on fabrication of individualized orthodontic archwires. Recently introduced, digital model technology may offer a limitation for the obtainment of a dental physical record. In this context, a tool for dental arch form assessment for chairside use is necessary when employing digital models. In this regard, paper print of the dental arch seems thus to be useful. Methods: In the present study, 37 lower arch models were used. Intercanine and intermolar widths and dental arch length measurements were performed and compared using plaster dental casts, digital models and paper print image of the models. Ortho Insight 3D scanner was employed for model digitalization. Results: No statistically significant differences were noted regarding the measurements performed on the plaster or digital models (p> 0.05. Paper print images, however, showed subestimated values for intercanine and intermolar widths and overestimated values for dental arch length. Despite being statistically significant (p< 0.001, the differences were considered clinically negligible. Conclusion: The present study suggests that paper print images obtained from digital models are clinically accurate and can be used as a tool for dental arch form assessment for fabrication of individualized orthodontic archwires. 16. Digital models: How can dental arch form be verified chairside? Science.gov (United States) Tavares, Alana; Braga, Emanuel; de Araújo, Telma Martins 2017-01-01 ABSTRACT Introduction: Plaster dental casts are routinely used during clinical practice to access maxillary dental arch form and assist on fabrication of individualized orthodontic archwires. Recently introduced, digital model technology may offer a limitation for the obtainment of a dental physical record. In this context, a tool for dental arch form assessment for chairside use is necessary when employing digital models. In this regard, paper print of the dental arch seems thus to be useful. Methods: In the present study, 37 lower arch models were used. Intercanine and intermolar widths and dental arch length measurements were performed and compared using plaster dental casts, digital models and paper print image of the models. Ortho Insight 3D scanner was employed for model digitalization. Results: No statistically significant differences were noted regarding the measurements performed on the plaster or digital models (p> 0.05). Paper print images, however, showed subestimated values for intercanine and intermolar widths and overestimated values for dental arch length. Despite being statistically significant (p< 0.001), the differences were considered clinically negligible. Conclusion: The present study suggests that paper print images obtained from digital models are clinically accurate and can be used as a tool for dental arch form assessment for fabrication of individualized orthodontic archwires. PMID:29364382 17. [Quantitative evaluation of printing accuracy and tissue surface adaptation of mandibular complete denture polylactic acid pattern fabricated by fused deposition modeling technology]. Science.gov (United States) Deng, K H; Wang, Y; Chen, H; Zhao, Y J; Zhou, Y S; Sun, Y C 2017-06-09 Objective: To quantitatively evaluate the adaptation of polylactic acid (PLA) pattern of mandibular complete denture fabricated by fused deposition modeling (FDM) technology. Methods: A mandibular complete denture digital model was designed through a complete denture design software based on a pair of standard maxillomandibular edentulous plaster model and their occlusion bases. Ten PLA mandibular complete dentures were printed with a FDM machine. The dentures were scanned with and without the plaster model using a three-dimensional (3D) scanner. In Geomagic software, the scanning data of printed dentures were registered to its computer aided design (CAD) data, and the printing error was analyzed using the multipoint registration command. For quantitatively evaluating the adaptation of the denture, the data of plaster model and PLA denture were registered to the whole data of denture located in the plaster model using the best-fit alignment command, the 3D deviation of the plaster model and tissue surface of the denture represent the space between them. The overall area was separated into three parts: primary stress-bearing area, secondary stress-bearing area and border seal area, and the average deviations of these three parts were measured. The values were analyzed using analysis of variance. Results: Compared with the CAD data, the printing error was (0.013±0.004) mm. The overall 3D deviation between PLA denture and plaster model was (0.164±0.033) mm, in which the primary stress-bearing area was (0.165± 0.045) mm, the secondary stress-bearing area was (0.153 ± 0.027) mm, the border seal area was (0.186 ± 0.043) mm. These showed a good fit in the majority parts of the FDM denture to the plaster model. No statistically significant difference was observed between the three areas ( F =1.857, P =0.175>0.05). Conclusions: Combined with the 3D scanning, CAD and FDM technology, a FDM 3D printing process of complete denture for injection moulding can be established 18. Simplified Model Surgery Technique for Segmental Maxillary Surgeries Directory of Open Access Journals (Sweden) Namit Nagar 2011-01-01 Full Text Available Model surgery is the dental cast version of cephalometric prediction of surgical results. Patients having vertical maxillary excess with prognathism invariably require Lefort I osteotomy with maxillary segmentation and maxillary first premolar extractions during surgery. Traditionally, model surgeries in these cases have been done by sawing the model through the first premolar interproximal area and removing that segment. This clinical innovation employed the use of X-ray film strips as separators in maxillary first premolar interproximal area. The method advocated is a time-saving procedure where no special clinical or laboratory tools, such as plaster saw (with accompanying plaster dust, were required and reusable separators were made from old and discarded X-ray films. 19. Late Glacial temperature and precipitation changes in the lowland Neotropics by tandem measurement of δ 18O in biogenic carbonate and gypsum hydration water Science.gov (United States) Hodell, David A.; Turchyn, Alexandra V.; Wiseman, Camilla J.; Escobar, Jaime; Curtis, Jason H.; Brenner, Mark; Gilli, Adrian; Mueller, Andreas D.; Anselmetti, Flavio; Ariztegui, Daniel; Brown, Erik T. 2012-01-01 We applied a new method to reconstruct paleotemperature in the tropics during the last deglaciation by measuring oxygen isotopes of co-occurring gypsum hydration water and biogenic carbonate in sediment cores from two lakes on the Yucatan Peninsula. Oxygen and hydrogen isotope values of interstitial and gypsum hydration water indicate that the crystallization water preserves the isotopic signal of the lake water, and has not undergone post-depositional isotopic exchange with sediment pore water. The estimated lake water δ18O is combined with carbonate δ18O to calculate paleotemperature. Three paired measurements of 1200-yr-old gypsum and gastropod aragonite from Lake Chichancanab, Mexico, yielded a mean temperature of 26 °C (range 23-29.5 °C), which is consistent with the mean and range of mean annual temperatures (MAT) in the region today. Paired measurements of ostracods, gastropods, and gypsum hydration water samples were measured in cores from Lake Petén Itzá, Guatemala, spanning the Late Glacial and early Holocene period (18.5-10.4 ka). The lowest recorded temperatures occurred at the start of Heinrich Stadial (HS) 1 at 18.5 ka. Inferred temperatures from benthic ostracods ranged from 16 to 20 °C during HS 1, which is 6-10 °C cooler than MAT in the region today, whereas temperatures derived from shallow-water gastropods were generally warmer (20-25 °C), reflecting epilimnetic temperatures. The derived temperatures support previous findings of greater tropical cooling on land in Central America during the Late Glacial than indicated by nearby marine records. Temperature increased in two steps during the last deglaciation. The first occurred during the Bolling-Allerod (B-A; from 14.7 to 13 ka) when temperature rose to 20-24 °C towards the end of this period. The second step occurred at 10.4 ka near the beginning of the Holocene when ostracod-inferred temperature rose to 26 °C, reflecting modern hypolimnetic temperature set during winter, whereas 20. Extension of the possibilities for disposal of the flue gas desulfurization (FGD) gypsum by the development of a process for the production of FGD gypsum. Final report. Erweiterung der Entsorgungsmoeglichkeiten von REA-Gips durch Entwicklung eines Verfahrens zur Herstellung von REA-Anhydrit aus REA-Gips. Schlussbericht Energy Technology Data Exchange (ETDEWEB) Limmer, B.; Hueller, R. 1990-01-01 In the course of this research project a completly new transformation of FGD-gypsum into FGD-anhydrite has been studied. The reaction is catalysed by small quantities of sulphuric acid resulting in a FGD-anhydrite without combined water and with an orthorhombic crystal lattice. The course of reaction was thoroughly investigated by laboratory test and hypothesis have been put forward. The process engineering has been developed from laboratory to pilot plant scale. The FGD-anhydrite is technologically a novel product. The idea was to create it for cement industry as well as to put it on the filler market as a raw product. In principle, FGD-anhdrite will be suitable for the use in the cement industry due to its characteristics. However, it is not interesting for this market in this moment. With respect to the filler industry, this application will enable a further-reaching usability of the FGD-gypsum than the traditional scope of the gypsum industry. First experiments show that the specific properties of processed FGD-anhydrite may qualify it as a high-grade filler. (orig.) With 18 refs., 21 tabs., 41 figs. 1. Phosphorus, nitrogen, and radionuclide retention and leaching from a Joel sand amended with red mud/gypsum International Nuclear Information System (INIS) McPharlin, L.R.; Jeffery, R.C.; Toussaint, L.F.; Cooper, M. 1994-01-01 The leaching of phosphorus (P), nitrogen (N), and radionuclides 232 Th, 226 Ra, 228 Ra, and 40 K from Joel sands amended with red mud/gypsum (RMG) at 9 rates (0, 2, 4, 8, 16, 32, 64, 128, and 256 t/ha) was measured using columns. Intense leaching conditions (34 mm/day for 12 days) and a high rate of applied P (320 kg/ha as superphosphate) and N (680 kg/ha as ammonium nitrate) were used to simulate extremes of irrigated vegetable production on the Swan Coastal Plain. Addition of the highest rate of RMG (256 t/ha) reduced leaching of fertiliser P and ammonium-nitrogen (NH4-N) by 85% and 50%, respectively, compared with 0 t/ha after 12 days. At 64 t RMG/ha P leaching was reduced 50% compared with 0 t/ha. Nitrate-nitrogen (NO3-N) leaching was not affected by addition of RMG. Reduced leaching of NH4-N was attributed to an increase in cation exchange capacity of the soil with the addition of RMG. Bicarbonate-extractable P in the soil increased with rate of RMG to >50 μg P/g soil at 256 t/ha. This indicates that soil testing of residual P could be used to reduce P inputs to vegetable crops after soils were amended with RMG. This would further reduce the impact of vegetable production on the water systems of the Swan Coastal Plain and extend the period of effectiveness of RMG amended soils. The increase in 232 Th specific activity in Joel sand amended with RMG was well below statutory limits even at the highest rate. Neither 40 K nor 226 Ra were detectable in RMG amended sands up to 256 t RMG/ha. There was no evidence of leaching of 226 Ra or 228 Ra at any rate of RMG. These results suggest that the use of RMG amendment on commercial horticultural properties on the Swan Coastal Plain could be feasible. 30 refs., 7 figs., 2 tabs 2. The Environmental Impact and Cost Analysis of Concrete Mixing Blast Furnace Slag Containing Titanium Gypsum and Sludge in South Korea Directory of Open Access Journals (Sweden) Tae Hyoung Kim 2016-05-01 Full Text Available This study assessed the environmental effects and cost of the Industrial Waste addictive Blast Furnace Slag (W-BFS using Life Cycle Assessment (LCA and compared it to general BFS. The environmental impacts of W-BFS were as follows: 1.12 × 10−1 kg-CO2 eq/kg, 3.18 × 10−5 kg-Ethylene eq/kg, 4.79 × 10−4 kg-SO2 eq/kg, 7.15 × 10−4 kg-PO43− eq/kg, 7.15 × 10−4 kg-CFC11 eq/kg and 3.94 × 10−3 kg-Antimony eq/kg. Among the environmental impact category, GWP and AP were 9.28 × 10−2 kg-CO2 eq/kg and 3.33 × 10−4 kg-SO2 eq/kg at a raw material stage, accounting for 80% and 70% of total environmental impact respectively. In EP, POCP and ADP, in addition, raw material stage accounted for a great portion in total environmental impact because of “W” among input materials. In ODP, however, compared to the environmental impact of raw materials, oil, which was used in transporting BFS to the W-BFS manufacturing factory, was more influential. In terms of GWP, POCP and ODP, W-BFS was higher than general BFS. In terms of AP, EP and ADP, in contrast, the former was lower than the latter. In terms of cost, W-BFS (41.7 US/ton was lower than general BFS by about 17% because of the use of waste additives comprised of industrial wastes instead of natural gypsum ,which has been commonly used in general BFS. In terms of GWP and POCP, the W-BFS mixed (30% concrete was lower than plain concrete by 25%. In terms of AP and EP, the former was lower than the latter by 30%. In terms of ADP, furthermore, W-BFS mixed (30% concrete was lower than plain concrete by 11%. In aggregate-related ODP, however, almost no change was found. In terms of cost, when W-BFS was added by 10% and 30%, it was able to reduce cost by 3% and 7% respectively, compared to plain concrete. Compared to BFS-mixed concrete as well, cost could be saved by 1% additionally because W-BFS (US$41.7/ton is lower than common cement (US$100.3/ton by about 60% in terms of production costs.
3. [Experimental evaluation of the spraying disinfection efficiency on dental models].
Science.gov (United States)
Zhang, Yi; Fu, Yuan-fei; Xu, Kan
2013-08-01
To evaluate the disinfect effect after spraying a new kind of disinfectant on the dental plaster models. The germ-free plaster samples, which were smeared with bacteria compound including Staphylococcus aureus, Escherichia coli, Saccharomyces albicans, Streptococcus mutans and Actinomyces viscosus were sprayed with disinfectants (CaviCide) and glutaraldehyde individually. In one group(5 minutes later) and another group(15 minutes later), the colonies were counted for statistical analysis after sampling, inoculating, and culturing which were used for evaluation of disinfecting efficiency. ANOVA was performed using SPSS12.0 software package. All sample bacteria were eradicated after spraying disinfectants(CaviCide) within 5 minutes and effective bacteria control was retained after 15 minutes. There was significant difference between the disinfecting efficiency of CaviCide and glutaraldehyde. The effect of disinfection with spraying disinfectants (CaviCide) on dental models is quick and effective.
4. 石氏针药结合治疗急性踝关节扭伤早期疗效研究%Clinical Observation on the Treatment of Acute Ankle Sprain by Shi's Acupuncture Therapy Combined with Compound Zijing Plaster
Institute of Scientific and Technical Information of China (English)
李涛; 郭海玲; 杨光月; 商海滨; 赵咏芳
2017-01-01
目的:研究石氏针刺结合复方紫荆消伤膏外用治疗急性踝关节扭伤早期症状改善特点,评价石氏针刺结合外用膏药治疗急性踝关节扭伤、弹力绷带固定治疗和功能锻炼治疗的优效性.方法:对上海市浦东新区6家医院2014年1月至2016年10月收治的300例急性踝关节扭伤患者随机分为针药结合治疗组、弹力绷带固定组和功能锻炼组,三组受试者分别予石氏针刺结合膏药外用治疗,弹力绷带固定结合膏药治疗和功能锻炼处方结合膏药治疗.在入组时(入组)、第7天(第1周、访视一)、第28天(第4周、访视二)和第42天(第6周、访视三)采用美国足踝外科学会AOFAS踝后足评分量表、VAS疼痛评分进行优效性评价.结果:三种治疗方法对急性踝关节扭伤均有疗效(P＜0.05).在第7天,针药结合组AOFAS评分与绷带固定组和功能锻炼组差异有统计学意义(P＜0.05),针药结合组AOFAS评分高于绷带固定组和功能锻炼组评分.在第7天、第28天针药结合组VAS疼痛评分变化与绷带固定组和功能锻炼组差异有统计学意义(P＜0.05),针药结合组VAS疼痛评分改善大于弹力绷带固定组和功能锻炼组.针药结合组AOFAS疗效评定痊愈率和VAS疼痛疗效评定痊愈率高于绷带固定组和功能锻炼组(P＜0.05).结论:石氏针药结合治疗急性踝关节扭伤临床疗效明确,对损伤早期的疼痛改善和功能恢复疗效优于弹力绷带固定治疗和功能锻炼治疗.%Objective:To study the improvement characteristics of early symptoms of acute ankle sprain treated with the Shi's acupuncture therapy combined with compound Zijing plaster,and to evaluate the superiority of the Shi's therapy combined with topical plaster,elastic bandage fixation and functional exercise therapy in the treatment of acute ankle sprain.Methods:All 300 cases of acute ankle sprain patients were randomly assigned to groups of Shi's therapy
5. The Accuracy and Reproducibility of Linear Measurements Made on CBCT-derived Digital Models.
Science.gov (United States)
2016-04-01
To evaluate the accuracy and reproducibility of linear measurements made on cone-beam computed tomography (CBCT)-derived digital models. A total of 25 patients (44% female, 18.7 ± 4 years) who had CBCT images for diagnostic purposes were included. Plaster models were obtained and digital models were extracted from CBCT scans. Seven linear measurements from predetermined landmarks were measured and analyzed on plaster models and the corresponding digital models. The measurements included arch length and width at different sites. Paired t test and Bland-Altman analysis were used to evaluate the accuracy of measurements on digital models compared to the plaster models. Also, intraclass correlation coefficients (ICCs) were used to evaluate the reproducibility of the measurements in order to assess the intraobserver reliability. The statistical analysis showed significant differences on 5 out of 14 variables, and the mean differences ranged from -0.48 to 0.51 mm. The Bland-Altman analysis revealed that the mean difference between variables was (0.14 ± 0.56) and (0.05 ± 0.96) mm and limits of agreement between the two methods ranged from -1.2 to 0.96 and from -1.8 to 1.9 mm in the maxilla and the mandible, respectively. The intraobserver reliability values were determined for all 14 variables of two types of models separately. The mean ICC value for the plaster models was 0.984 (0.924-0.999), while it was 0.946 for the CBCT models (range from 0.850 to 0.985). Linear measurements obtained from the CBCT-derived models appeared to have a high level of accuracy and reproducibility.
6. Gypsum effects on soil chemical properties under two management systemsEfeito do gesso nas propriedades químicas do solo sob dois sistemas de manejo
Directory of Open Access Journals (Sweden)
Yara Brito Chaim Jardim Rosa
2012-10-01
Full Text Available The combination of gypsum application and soil management may influence soil chemical properties. In this context, the aim of this paper was to evaluate soil chemical properties under two management systems and residual gypsum in soil after 55 months from treatment application. This experiment was developed in FCA/UFGD in Dourados-MS, Brazil under a randomized block design with subdivided plots and four replications. Main plots, subplots and subsubplots consisted of tillage systems (conventional and no tillage, gypsum application and soil depth (0-0,05, 0,05-0,10, 0,10-0,15, 0,15-0,20 and 0,20-0,30 m, respectively. There were no effects of residual gypsum on calcium levels. The combination of no tillage system and residual gypsum increased potassium and sulfur as well as reduced potential acidity. However, residual gypsum increased soil potential acidity in conventional system. No tillage system increased calcium levels in the depths 0-0.05 and 0.05-0.10 m, organic matter down to 0.05 m, sulfur accumulation in the depths 0.05-0.10 and 0.10-0.15 m, sum of bases and base saturation in the depth 0.05-0.10. Conversely, magnesium levels in the depth 0.10-0.15 m, phosphorus from 0.05 to 0.15 m, potential acidity from 0.05 to 0.10 m and ECC in the depth 0.10-0.15 m were decreased. Effects of residual gypsum increased sulfur and base saturation from 0.20 to 0.30 m, but decreased magnesium and phosphorus levels in the depth 0.05-0.10 m. Soil active acidity and potassium levels were decreased in deeper soil layers. A combinação de gessagem e manejo do solo podem influenciar as propriedades químicas do solo. Neste contexto, o objetivo deste trabalho foi avaliar as propriedades químicas do solo submetido a dois manejos do solo e ao efeito residual de gesso, após 55 meses de implantação dos tratamentos. Desenvolvido em uma área experimental da FCA/UFGD de Dourados, MS, o experimento foi disposto no delineamento de blocos casualizados com os fatores
7. [Reliability of three dimensional resin model by rapid prototyping manufacturing and digital modeling].
Science.gov (United States)
Zeng, Fei-huang; Xu, Yuan-zhi; Fang, Li; Tang, Xiao-shan
2012-02-01
To describe a new technique for fabricating an 3D resin model by 3D reconstruction and rapid prototyping, and to analyze the precision of this method. An optical grating scanner was used to acquire the data of silastic cavity block , digital dental cast was reconstructed with the data through Geomagic Studio image processing software. The final 3D reconstruction was saved in the pattern of Stl. The 3D resin model was fabricated by fuse deposition modeling, and was compared with the digital model and gypsum model. The data of three groups were statistically analyzed using SPSS 16.0 software package. No significant difference was found in gypsum model,digital dental cast and 3D resin model (P>0.05). Rapid prototyping manufacturing and digital modeling would be helpful for dental information acquisition, treatment design, appliance manufacturing, and can improve the communications between patients and doctors.
8. Adhesives in Building--Lamination of Structural Timber Beams, Bonding of Cementitious Materials, Bonding of Gypsum Drywall Construction. Proceedings of a Conference of the Building Research Institute, Division of Engineering and Industrial Research (Spring 1960).
Science.gov (United States)
National Academy of Sciences - National Research Council, Washington, DC.
The role of adhesives in building design is discussed. Three major areas are as follows--(1) lamination of structural timber beams, (2) bonding of cementitious materials, and (3) bonding of gypsum drywall construction. Topical coverage includes--(1) structural lamination today, (2) adhesives in use today, (3) new adhesives needed, (4) production…
9. Lime and gypsum to improve root depth of orange crop in an Ultisol of the Coastal Tablelands Calcário e gesso no aprofundamento radicular da laranjeira em um Argissolo dos Tabuleiros Costeiros
Directory of Open Access Journals (Sweden)
Lafayette F. Sobral
2009-12-01
10. Shujin Chubi Zhuanggu plaster and massage in the treatment of acute ankle sprain%舒筋除痹壮骨膏联合推拿治疗急性踝关节扭伤的临床观察
Institute of Scientific and Technical Information of China (English)
沈玉杰; 李玉久; 董焘
2016-01-01
目的：观察舒筋除痹壮骨膏联合推拿治疗急性踝关节扭伤的疗效及安全性。方法：选取本院收治的急性踝关节扭伤患者78例，随机分为膏摩组39例和推拿组39例，膏摩组给予舒筋除痹壮骨膏联合推拿治疗（称为膏摩疗法），推拿组给予单纯的传统推拿疗法，观察两组治疗前后症状改善情况及治疗效果。结果：膏摩组有效率为100．0％，推拿组有效率为97．4％；膏摩组治愈率89．7％，明显高于推拿组治愈率（64．1％），P ＜0．05；两组患者治疗前 AO-FAS 踝-后足评分比较，无差异，P＞0．05；治疗后第3d 、7d 、14d 、30d 时 AOFAS 踝-后足评分比较，差异显著，P＜0．05。结论：对于急性踝关节扭伤用舒筋除痹壮骨膏联合推拿治疗，临床效果较好，安全性高，患者容易接受。%Objective :To observe the efficacy and safety of Shujin Chubi Zhuanggu plaster combined with mas-sage treatment of ankle sprain .Methods :78 cases in our hospital of acute ankle sprain patients were randomly divided in-to Gaomo group of 39 cases and 39 cases of massage group ,ointment massage group received Shujin Chubi Zhuanggu plaster combined with massage therapy (called paste massage) ,the massage group received traditional massage therapy a-lone ,two groups were observed before and after treatment the improvement of symptoms and therapeutic effect .Results :The effective rate of Gaomo group was 100% ,the massage group was 97 .4% ;Gaomo group the cure rate was 89 .7% , significantly higher than the massage group cure the rate (64 .1% ) ,P 0 .05 ;after treatment ,3d ,7d ,14d ,30d AOFAS ankle hindfoot score comparison ,significant difference , P < 0 .05 .Conclusion :For acute ankle sprain with Shujin Chubi Zhuanggu plaster combined with massage therapy ,the clinical effect is good ,high safety ,easy to accept patients .
11. Application of reject of gypsum from Trindade/PE in ceramic masses formulations; Aplicacao de residuos de gipsita em formulacoes de massas ceramicas
Energy Technology Data Exchange (ETDEWEB)
Lima, Thalles Confessor de; Souza, Marcondes Mendes de; Almeida, Ana Beatriz Dantas de; Farias, Debora Santos Umbelino de; Nobrega, Luiz Felipe Pereira de Medeiros, E-mail: [email protected] [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio Grande do Norte (IFRN), Mossoro, RN (Brazil); Mendes, Luciana Bezerra [Fundacao de Apoio a Pesquisa do Rio Grande do Norte (FAPERN), Natal RN (Brazil)
2016-07-01
The mining industry is a major producer of waste is to be harmful to the environment besides not being made possible for use in producing means, since the product of economic interest has been extracted. In order to reduce this problem, this work shows the characterization of the waste generated by gypsum mining in Trindade/PE in the ceramic coating. The residue was collected, ground and sieved to #200, then was chemically characterized by XRF analysis process, to evaluate its potential to be incorporated into the formulation of ceramic material, the material studied can be used in porcelain tile formulation as a flux element for that were obtained in the laboratory ceramic bodies adding the residue then were performed physical testing of linear shrinkage, water absorption and flexural breaking strain technically order to evaluate the addition of this residue ceramic coating. (author)
12. Resposta da alfafa a fontes de fósforo associadas ao gesso e à calagem Alfalfa response to phosphorus sources associated to gypsum and liming
Directory of Open Access Journals (Sweden)
Patrícia Sarmento
2001-06-01
13. Production development and utilization of Zimmer Station wet FGD by-products. Final report. Volume 6, Field study conducted in fulfillment of Phase 3 titled. Use of FGD by-product gypsum enriched with magnesium hydroxide as a soil amendment
Energy Technology Data Exchange (ETDEWEB)
Bigham, J. M. [Ohio State Univ., Wooster, OH (United States). Ohio Agricultural Research Development Center; Soto, U. I. [Ohio State Univ., Wooster, OH (United States). Ohio Agricultural Research Development Center; Stehouwer, R. C. [Ohio State Univ., Wooster, OH (United States). Ohio Agricultural Research Development Center; Yibirin, H. [Ohio State Univ., Wooster, OH (United States). Ohio Agricultural Research Development Center
1999-04-30
A variety of flue gas desulfurization (FGD) technologies have been developed to meet environmental restrictions imposed by the federal Clean Air Act and its amendments. These technologies include wet scrubber systems that dramatically reduce sulfur dioxide (SO2) emissions. Although such systems are effective, they also produce large volumes of sludge that must be dewatered, stabilized, and disposed of in landfills. Disposal is an expensive and environmentally questionable process for which suitable alternatives are needed. Wet scrubbing of flue gases with magnesium (Mg)-enhanced lime has the potential to become a leading FGD technology. When combined with aforced oxidation system, the wet sludges resulting from this process can be modified and refined to produce gypsum (CaS04∙2H2O) and magnesium hydroxide [Mg(OH)2] of sufficient purity for beneficial re-use in the construction (wallboard) and pharmaceutical industries. The pilot plant at the CINERGY Zimmer Station near Cincinnati can also produce gypsum by-products formulated to contain varying amounts of Mg(OH)2- Such materials may have value to the agriculture, forestry, and lawn-care industries as soil "conditioners", liming agents, and nutritional supplements capable of supplying calcium (Ca), Mg, and sulfur (S) for plant growth. This report describes three field studies designed to evaluate by-product gypsum and Mg-gypsum from the Zimmer Station power plant as amendments for improving the quality of mine spoils and agricultural soils that were unproductive because of phytotoxic levels of dissolved aluminum (Al) and low pH. The technical literature suggests that gypsum may be more effective than agricultural limestone for ameliorating Al toxicity below the immediate zone of application. Such considerations are important for deep-rooted plant species that attempt to utilize water and nutrients occurring at depth in the spoil/soil.
14. Balances of radionuclides and trace in the valuation in the waste valuation of rich plaster using a CO{sub 2} capture process; Balances de radionucleidos y elementos traza en la valoracion de residuos ricos en yeso mediante un proceso de captura del CO{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Perez-Moreno, S. M.; Contreras, M.; Gazquez, M. J.; Bolivar, J. P.
2013-07-01
Waste covered by this study come from two industries NORM (Naturally Ocurring Radioactive Material) located in Huelva: a production of titanium dioxide and a phosphate fertilizer. These industries generate red drywall and phosphogypsum waste. The main objective of this study was to evaluate the distribution of radionuclides and trace elements in the process of using of red plaster and phosphogypsum as agents CO{sub 2} captors. (Author)
15. Relationship between pore structure and compressive strength of ...
J BU
compressive strength relationship in ... He applied this equation to experimental data on gypsum plasters and ... Popovics [15] observes that this is true even for different types of ... proportions and curing ages of concrete samples are listed in table 1.
16. Efeitos da adição de gesso agrícola à cama aviária sobre o desempenho de frangos de corte Effects of agricultural gypsum addition to broiler litter on broilers performance
Directory of Open Access Journals (Sweden)
Luís Daniel Giusti Bruno
1999-04-01
17. Simultaneous analysis of 17O/16O, 18O/16O and 2H/1H of gypsum hydration water by cavity ring‐down laser spectroscopy
Science.gov (United States)
Mather, Ian; Rolfe, James; Evans, Nicholas P.; Herwartz, Daniel; Staubwasser, Michael; Hodell, David A.
2015-01-01
Rationale The recent development of cavity ring‐down laser spectroscopy (CRDS) instruments capable of measuring 17O‐excess in water has created new opportunities for studying the hydrologic cycle. Here we apply this new method to studying the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of gypsum hydration water (GHW), which can provide information about the conditions under which the mineral formed and subsequent post‐depositional interaction with other fluids. Methods We developed a semi‐automated procedure for extracting GHW by slowly heating the sample to 400°C in vacuo and cryogenically trapping the evolved water. The isotopic composition (δ17O, δ18O and δ2H values) of the GHW is subsequently measured by CRDS. The extraction apparatus allows the dehydration of five samples and one standard simultaneously, thereby increasing the long‐term precision and sample throughput compared with previous methods. The apparatus is also useful for distilling brines prior to isotopic analysis. A direct comparison is made between results of 17O‐excess in GHW obtained by CRDS and fluorination followed by isotope ratio mass spectrometry (IRMS) of O2. Results The long‐term analytical precision of our method of extraction and isotopic analysis of GHW by CRDS is ±0.07‰ for δ17O values, ±0.13‰ for δ18O values and ±0.49‰ for δ2H values (all ±1SD), and ±1.1‰ and ±8 per meg for the deuterium‐excess and 17O‐excess, respectively. Accurate measurement of the 17O‐excess values of GHW, of both synthetic and natural samples, requires the use of a micro‐combustion module (MCM). This accessory removes contaminants (VOCs, H2S, etc.) from the water vapour stream that interfere with the wavelengths used for spectroscopic measurement of water isotopologues. CRDS/MCM and IRMS methods yield similar isotopic results for the analysis of both synthetic and natural gypsum samples within analytical error of the two methods. Conclusions We
18. Localization, Weakening and Fluid-rock Coupling Mechanisms in Gypsum: Development and Initial Data From a New, Combined, Rotary Shear and Acoustic Emission Apparatus.
Science.gov (United States)
Benson, P. M.; Pozzi, G.; Guerin-Marthe, S.; De Paola, N.; Nielsen, S. B.; Tomas, R.
2017-12-01
We present initial pilot data from a newly developed apparatus designed to measure Acoustic Emissions (AE) during the shear of fault gouges to 25 MPa normal stress and up to a maximum speed of 1 m/s, simulating dynamic earthquake processes. The sample assembly consists of a titanium-vanadium alloy (Ti-alloy, Ti90Al6V4) anvil fitted with 6 ports on the lower (stationary) section for AE sensors that record the activity of the shearing occurring in the gouge layer above. AE data are amplified from between 6 to 70 dB and recorded to disk continuously at a sampling rate of 10 MHz; calibration tests with Teflon shims confirm that the machine noise is negligible. Gouge thicknesses of approximately 2 mm are used, confined with a Teflon ring. Here we focus on Gypsum gouge from the Volterra region of Italy, sieved to give a constant gouge range of between 63 to 90 micrometers. Mechanical data show the onset of weakening after a slip of 1-3 cm for velocities of v = 100 to 1 cm s-1 respectively. Microstructural observations reveal a shear zone bounded by sharp mirror surfaces, and the development of a dehydration front, which is likely to have produced small pockets of water. We also record a characteristic `pulsing' AE signal generated after shearing is arrested, manifested as a series of energy spikes occurring at regular intervals. However, these signals are only generally seen for shear tests conducted on gypsum gouges (not in anhydrite) at 10cm per second or higher. Taken together, we interpret these observations as evidence that the initial shearing generated a thin slip zone that heats up rapidly, generating the dehydration front. Once motion ceases, pockets of trapped pressurized water combined with thermal stress generates distributed micro-fracturing detected as an initial swarm of high energy AE, and allows fluids to vent in pulses to the ambient atmosphere. An initial seismic -b value analysis of the continuous AE waveform also supports these initial findings.
19. Thermal Dehydration Kinetics of Gypsum and Borogypsum under Non-isothermal Conditions%在非等温条件下石膏和硼石膏的加热脱水动力学研究
Institute of Scientific and Technical Information of China (English)
ī.Y.Elbeyli; S.Piskin
2004-01-01
Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides.
20. Aplicação de gesso e calcário na recuperação de solos salino-sódicos do Estado de Pernambuco Application of gypsum and limestone in the reclamation of saline-sodic soils of the Pernambuco State
Directory of Open Access Journals (Sweden)
Maria de F. C. Barros
2005-09-01
Full Text Available Experimento em colunas de solo foi conduzido, objetivando-se avaliar o efeito da aplicação de gesso e gesso + calcário, na recuperação de solos salino-sódicos do Perímetro Irrigado de Custódia, PE. Os tratamentos foram dispostos em um delineamento em blocos casualizados, com arranjo fatorial de quatro solos, dois métodos de aplicação de gesso e gesso + calcário (aplicados na superfície e incorporados aos primeiros 5 cm da coluna de solo, duas combinações dos corretivos (100% de gesso + 0% de calcário e 80% de gesso + 20% de calcário, calculados com base na necessidade de gesso dos solos, e quatro faixas de granulometria de gesso (2,0-1,0, 1,0-0,5, 0,5-0,3 e An experiment was carried out in soil columns with the objective of evaluating the effect of application of gypsum and limestone on reclamation of the saline-sodic soils in the Irrigation district of Custódia, PE. The treatments were arranged in a randomized block design in a factorial scheme of four soils, two methods for applications of gypsum and gypsum plus limestone (applied on surface and incorporated into the first five cm of the soil column, two combinations of the chemical amendments (100% gypsum plus 0% limestone and 80% gypsum plus 20% limestone, calculated on the basis of gypsum requirement of soil and four granulometry gypsum strips (2.0-1.0; 1.0-0.5; 0.5-0.3 and < 0.3 mm with three replications. The gypsum amount determined by the method of Schoonover M-1, under laboratory conditions, shows to be adequate in the displacement of the exchangeable sodium of the soil exchange complex. The efficiency of the gypsum as well as the gypsum plus lime mixture in reclamation of the soils shows to be superior, when the amendments are incorporated into the first 5 cm of the soil columns. Among the gypsum granulometry, the finest fractions, (0.5-0.3 mm and < 0.3 mm, presented better performance in replacing the exchangeable sodium of the exchange complex.
1. Early age hydration of calcium sulfoaluminate (synthetic ye'elimite, ) in the presence of gypsum and varying amounts of calcium hydroxide
KAUST Repository
Hargis, Craig W.
2013-06-01
Suspensions of synthetic ye\\'elimite (C4A3S̄) in a saturated gypsum (CS̄H2) and calcium hydroxide (CH) solution were examined in-situ in a wet cell by soft X-ray transmission microscopy and ex-situ by scanning electron microscopy. The most voluminous hydration product observed was ettringite. Ettringite commonly displayed acicular, filiform, reticulated, and stellate crystal habits. Additionally, pastes with C 4A3S̄, 15% CS̄H2, and varying amounts of CH were prepared and examined with X-ray diffraction (XRD) and isothermal calorimetry. The XRD experiments showed that increasing CH content caused more solid solution (SO4 2 -/OH-) AFm phases to form at early ages (< 1 d) and more monosulfate to form at later ages (> 1 d). Calorimetry indicated that the increased production of solid solution AFm was accompanied with an increase in the initial (< 30 min) rate of heat evolution, and increasing CH generally reduced the time till the second maximum rate of heat evolution due to the formation of ettringite and monosulfate. © 2013 Elsevier Ltd.
2. Early age hydration of calcium sulfoaluminate (synthetic ye'elimite, ) in the presence of gypsum and varying amounts of calcium hydroxide
KAUST Repository
Hargis, Craig W.; Kirchheim, Ana Paula; Monteiro, Paulo J.M.; Gartner, Ellis M.
2013-01-01
Suspensions of synthetic ye'elimite (C4A3S̄) in a saturated gypsum (CS̄H2) and calcium hydroxide (CH) solution were examined in-situ in a wet cell by soft X-ray transmission microscopy and ex-situ by scanning electron microscopy. The most voluminous hydration product observed was ettringite. Ettringite commonly displayed acicular, filiform, reticulated, and stellate crystal habits. Additionally, pastes with C 4A3S̄, 15% CS̄H2, and varying amounts of CH were prepared and examined with X-ray diffraction (XRD) and isothermal calorimetry. The XRD experiments showed that increasing CH content caused more solid solution (SO4 2 -/OH-) AFm phases to form at early ages (< 1 d) and more monosulfate to form at later ages (> 1 d). Calorimetry indicated that the increased production of solid solution AFm was accompanied with an increase in the initial (< 30 min) rate of heat evolution, and increasing CH generally reduced the time till the second maximum rate of heat evolution due to the formation of ettringite and monosulfate. © 2013 Elsevier Ltd.
3. Potential use of gypsum and lime rich industrial by-products for induced reduction of Pb, Zn and Ni leachability in an acid soil
International Nuclear Information System (INIS)
Rodriguez-Jorda, M.P.; Garrido, F.; Garcia-Gonzalez, M.T.
2010-01-01
This study evaluates the potential use of four industrial by-products (phosphogypsum (PG), red gypsum (RG), sugar foam (SF), and ashes from biomass combustion (ACB)), applied at two rates in single and combined amendments to reduce the mobility and availability of Pb, Zn and Ni in a metal-spiked acid soil. Leaching experiments were done to estimate leachability indexes and assess their effectiveness. Most of the treatments significantly reduced the metal leachability although only a few were effective for all metals. Based on principal component and cluster analysis, sugar foam (SF) and a mixture of RG and ACB (RG+ACB), both applied at high rate, were selected as first choices to reduce mobility and availability of the three metals. Metal sorption mechanisms involved in the reduction of their leachability were identified using scanning electron microscopy. In the SF-treated samples, the metals were found associated to amorphous Al-hydroxy polymers deposited on phyllosilicates and organic matter particles. In the (RG+ACB)-treated samples, Pb, Zn, and traces of Ni were found associated to Fe/Ti oxide phases with a significant concentration of S, suggesting the formation of metal-sulfate ternary complexes.
4. On Nonlinear Inverse Problems of Heat Transfer with Radiation Boundary Conditions: Application to Dehydration of Gypsum Plasterboards Exposed to Fire
OpenAIRE
Belmiloudi, A.; Mahé, F.
2014-01-01
International audience; The paper investigates boundary optimal controls and parameter estimates to the well-posedness nonlinear model of dehydration of thermic problems. We summarize the general formulations for the boundary control for initial-boundary value problem for nonlinear partial differential equations modeling the heat transfer and derive necessary optimality conditions, including the adjoint equation, for the optimal set of parameters minimizing objective functions J. Numerical si...
5. Barium isotope fractionation during the experimental transformation of aragonite to witherite and of gypsum to barite, and the effect of ion (de)solvation.
Science.gov (United States)
Böttcher, Michael E; Neubert, Nadja; von Allmen, Katja; Samankassou, Elias; Nägler, Thomas F
2018-06-01
In this study, we present the experimental results for stable barium (Ba) isotope fractionation ( 137 Ba/ 134 Ba) during the transformation of aragonite (CaCO 3 ) and gypsum (CaSO 4 ·2H 2 O) in Ba-bearing aqueous solution to witherite (BaCO 3 ) and barite (BaSO 4 ), respectively. The process was studied at three temperatures between 4 and 60 °C. In all cases, the transformation leads to a relative enrichment of the lighter 134 Ba isotope in the solid compared to the aqueous solution, with 137/134 Ba enrichment factors between -0.11 and -0.17 ‰ for BaCO 3 , and -0.21 and -0.26 ‰ for BaSO 4 . The corresponding mass-dependent 138/134 Ba enrichment factors are -0.15 to -0.23 ‰ for BaCO 3 , and -0.28 to -0.35 ‰ for BaSO 4 . The magnitude of isotope fractionation is within the range of recent reports for witherite and barite formation, as well as trace Ba incorporation into orthorhombic aragonite, and no substantial impact of temperature can be found between 4 and 80 °C. In previous studies, ion (de)solvation has been suggested to impact both the crystallization process of Ba-bearing solids and associated Ba isotope fractionation. Precipitation experiments of BaSO 4 and BaCO 3 using an methanol-containing aqueous solution indicate only a minor effect of ion and crystal surface (de)solvation on the overall Ba isotope fractionation process.
6. The efficacy and safety of S-flurbiprofen plaster in the treatment of knee osteoarthritis: a phase II, randomized, double-blind, placebo-controlled, dose-finding study
Directory of Open Access Journals (Sweden)
Yataba I
2017-04-01
Full Text Available Ikuko Yataba,1 Noboru Otsuka,1 Isao Matsushita,1 Hideo Matsumoto,2 Yuichi Hoshino3 1Taisho Pharmaceutical Co, Ltd, 2Institute for Integrated Sports Medicine, School of Medicine, Keio University, Tokyo, 3Department of Orthopedics Surgery, School of Medicine, Jichi Medical University, Tochigi, Japan Background: Nonsteroidal anti-inflammatory drug (NSAID patches are convenient for use and show much less gastrointestinal side effects than oral NSAIDs, whereas its percutaneous absorption is not sufficient for the expression of clinical efficacy at satisfactory level. S-flurbiprofen plaster (SFPP has shown dramatic improvement in percutaneous absorption results from animal and clinical studies. In this study, the efficacy and safety of SFPP were compared with placebo in patients with knee osteoarthritis (OA to determine its optimal dose. This was a multicenter, randomized, double-blind, parallel-group comparative study. Patients and methods: Enrolled 509 knee OA patients were treated with placebo or SFPP at 10, 20, or 40 mg applied on the affected site once daily for 2 weeks. The primary endpoint for efficacy was improvement in knee pain on rising from the chair assessed by visual analog scale (VAS. The other endpoints were clinical symptoms, pain on walking, and global assessment by both investigator and patient. Safety was evaluated by observing adverse events (AEs. Results: VAS change in knee pain from baseline to trial end was dose-dependent, least squares mean was 29.5, 31.5, 32.0, and 35.6 mm in placebo and SFPP 10, 20, and 40 mg, respectively. A significant difference was observed between placebo and SFPP 40 mg (P=0.001. In contrast, the effect of SFPP at a dose ≤20 mg was not significantly different from that of placebo. The proportion of the patients who achieved 50% pain relief was 72.4% in 40 mg and 51.2% in placebo (P<0.001. In all other endpoints, SFPP 40 mg showed significant improvement compared with placebo. The incidence of AEs was
7. Bribes and plasters won't do.
Science.gov (United States)
Coram, Michael
2017-08-23
I disagree with Graham Scott's editorial (9 August). We should not be bribing men into nursing, we should be fighting to reinstate the bursary for all healthcare students and be looking at the issues around gender stereotyping and perceptions relating to occupations.
8. Zile Elbaşoğlu Camii’nin Sıvalar Altında Kalan Gizemi The Mystery Of The Zile-Elbaşoğlu Mosque Remains Under Plasters
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Ali Murat AKTEMUR
2013-09-01
Full Text Available Elbaşoğlu Mosque was built in 1801 by Ahmet Aga, clean-cutstone architecture, square, rectangular with remarkable inscriptionsElbaşoğlu Mosque is one of the local mosque, wood-backed and woodenceilings. Until 2007, the walls and the ceiling, and even the altar,wooden support, wood columns, wooden gallery, galleries, in short, allthe wooden elements of the mosque was covered with oil on sweet-limeplaster. In 2007, during the repair of the roof of a simple chance, withplaster falling due to the flowing water under the pen-and-repair workon the emergence of ornaments and wooden decorations samples, thenstopped cleaning and scraper operations in the administration of theGeneral Directorate of Foundations in the interior of the mosque penrichsamples of work, with examples of wooden decorative plaster underthe mystery was revealed.Cover at the top of the walls combined with Harim calligraphy ona black background with spots, including a concave border of the beltframed verse was written. Verse generation raised on the corners of theceiling moldings created crash of beads, triangle, octagon in the middleof a field, and thus created the split surfaces. Located in the middle ofthe octagon octagon-shaped belly, finished with carving technique,baroque decorated with floral motifs. the four corners of the triangularroof panels are decorated with reliefs excess plastic plant. Pen-workdecoration floral motifs on the walls, gallery, pulpits, pillars, such asthe carved wooden elements fall floral and geometric motifs are carvedin the mosque offers a wealth of eye-catching as almost free space left.Made in 1801, in the early years of the Republic, the region'sunique sweet-lime paint on plaster taken off this rich decoration, woodart and pen-work ornamentation Turkey offers one of the richest. Tokat Zile’de Elbaşoğlu Ahmet Ağa tarafından 1801 yılında inşa ettirilen, düzgün kesme taş mimarisi, kitabeleri ile dikkat çeken, kareye yakın dikd
9. Incorporação de gesso para correção da salinidade e sodicidade de solos salino-sódicos Incorporation of gypsum to correct the salinity and sodicity of saline-sodic soils
Directory of Open Access Journals (Sweden)
Antonio N. Tavares Filho
2012-01-01
10. [Reconstruction and measurement of a digital dental model using grating projection and reverse engineering].
Science.gov (United States)
Zhenzhen, Wang; Yi, Lu; Jun, Song; Jun, Chen; Qin, Zhou
2015-02-01
This work lays the foundation for establishing a digital model database with normal occlusion. A digital dental cast is acquired through grating projection, and model features are measured through reverse engineering. The grating projection system controlled by a computer was projected onto the surface of a normal dental model. Three-dimensional contour data were obtained through multi-angle shooting. A three-dimensional model was constructed, and the model features were analyzed by using reverse engineering. The digital model was compared with the plaster model to determine the accuracy of the measurement system. The structure of three-dimensional reconstruction model was clear. The digital models of two measurements exhibited no significant difference (P > 0.05). When digital and plaster models were measured, we found that the crown length and arch width were not statistically different (P > 0.05), whereas the difference between the crown width and arch length was statistically significant (P model by using the grating projection technique and reverse engineering can be used for dental model measurement in clinic al and scientific research and can provide a scientific method for establishing a digital model database with normal occlusion.
11. Application of gypsum as shielding against low-energy X-radiation in the radiodiagnosis area; Aplicação do material gesso como blindagem contra radiação X de baixas energias na área de radiodiagnóstico
Energy Technology Data Exchange (ETDEWEB)
Lins, J.A.G.; Lima, F.R.A.; Santos, M.A.P. dos; Oliveira, D.N.S. de, E-mail: [email protected] [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Silva, V.H.F.F. da [Instituto Federal de Educação Ciência e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil)
2017-07-01
In recent years, materials such as lead, concrete and iron have been studied for use as shielding for ionizing radiations of different energies in radiative installations. In the radiodiagnosis area, lead and barite are the most used materials as shielding. However, for beams of low energy X-radiation, such as in mammography and dentistry, the gypsum material may be used. This study aims to verify the feasibility of the use of gypsum as shielding for low-energy X-ray using standardized dental X-ray beams in a metrology laboratory. The project will allow a better understanding in the study of gypsum used as shielding, certifying its use as a good attenuator for low-energy X-ray.
12. Alterações químicas do solo e resposta do milho à calagem e aplicação de gesso Changes in soil chemical properties and corn response to lime and gypsum applications
Directory of Open Access Journals (Sweden)
E. F. Caires
2004-02-01
13. Production development and utilization of Zimmer Station wet FGD by-products. Final report. Volume 5, A laboratory greenhouse study conducted in fulfillment of Phase 2, Objective 2 titled. Use of FGD by-product gypsum enriched with magnesium hydroxide as a soil amendment
Energy Technology Data Exchange (ETDEWEB)
Yibirin, H. [Ohio State Univ., Wooster, OH (United States); Stehouwer, R. C. [Ohio State Univ., Wooster, OH (United States); Bigham, J. M. [Ohio State Univ., Wooster, OH (United States); Soto, U. I. [Ohio State Univ., Wooster, OH (United States)
1997-01-31
The Clean Air Act, as revised in 1992, has spurred the development of flue gas desulfurization (FGD) technologies that have resulted in large volumes of wet scrubber sludges. In general, these sludges must be dewatered, chemically treated, and disposed of in landfills. Disposal is an expensive and environmentally questionable process for which suitable alternatives must be found. Wet scrubbing with magnesium (Mg)-enhanced lime has emerged as an efficient, cost effective technology for SO2 removal. When combined with an appropriate oxidation system, the wet scrubber sludge can be used to produce gypsum (CaSO4-2H2O) and magnesium hydroxide [Mg(OH)2] of sufficient purity for beneficial re-use. Product value generally increases with purity of the by-product(s). The pilot plant at the CINERGY Zimmer Station near Cincinnati produces gypsum by products that can be formulated to contain varying amounts of Mg(OH)2. Such materials may have agricultural value as soil conditioners, liming agents and sources of plant nutrients (Ca, Mg, S). This report describes a greenhouse study designed to evaluate by-product gypsum and Mg gypsum from the Zimmer Station pilot plant as amendments for improving the quality of agricultural soils and mine spoils that are currently unproductive because of phytotoxic conditions related to acidity and high levels of toxic dissolved aluminum (Al). In particular, the technical literature contains evidence to suggest that gypsum may be more effective than agricultural limestone in modifying soil chemical conditions below the immediate zone of application. Representative samples of by-product gypsum and Mg(OH)2 from the Zimmer Station were initially characterized. The gypsum was of high chemical purity and consisted of well crystalline, lath-shaped particles of low specific surface area. By contrast, the by-product Mg(OH)2 was a high surface area material (50 m2 g
14. Production of 34S-labeled gypsum (Ca34SO4.2H2O Produção de gesso (Ca34SO4.2H2O, marcado com 34S
Directory of Open Access Journals (Sweden)
Alexssandra Luiza Rodrigues Molina Rossete
2006-08-01
Full Text Available Agricultural gypsum (CaSO4.2H2O stands out as an effective source of calcium and sulfur, and to control aluminum saturation in the soil. Labeled as 34S it can elucidate important aspects of the sulfur cycle. Ca34SO4.2H2O was obtained by chemical reaction between Ca(OH2 and H2(34SO4, performed under slow agitation. The acid was produced by ion exchange chromatography using the Dowex 50WX8 cation exchange resin and a Na2(34SO4 eluting solution. After precipitation, the precipitate was separated and dried in a ventilated oven at 60ºC. From 2.2 L H2SO4 0.2 mol L-1 and 33.6 g Ca(OH2, 73.7 ± 0.6 g Ca34SO4.2H2O were produced on average in the tests, representing a mean yield of 94.6 ± 0.8%, with 98% purity. The 34SO2 gas was obtained from Ca34SO4.2H2O in the presence of NaPO3 in a high vacuum line and was used for the isotopic determination of S in an ATLAS-MAT model CH-4 mass spectrometer.O gesso agrícola (CaSO4.2H2O destaca-se como fonte eficiente de cálcio e enxofre e na redução da saturação de alumínio no solo. O 34S como traçador isotópico pode elucidar aspectos importantes no ciclo do enxofre. Para tanto o Ca34SO4.2H2O foi obtido por reação química entre o Ca(OH2 e solução de H2(34SO4, realizada sob agitação lenta. O ácido foi produzido por cromatografia de troca iônica, utilizando resina catiônica Dowex 50WX8 e solução eluente de Na2(34SO4. Após a precipitação foi separado o precipitado e realizada a secagem em estufa ventilada à temperatura de 60ºC. Nos testes, a partir de 2,2 L de H2SO4 0,2 mol L-1 e 33,6 g de Ca(OH2, foram produzidos em média 73,7 ± 0,6 g de Ca34SO4.2H2O representando um rendimento médio de 94,6 ± 0,8%, com pureza de 98%. A partir do Ca34SO4.2H2O na presença de NaPO3, em linha de alto vácuo, obteve-se o gás 34SO2 utilizado para a determinação isotópica do S no espectrômetro de massas ATLAS-MAT modelo CH-4.
15. 凉性经筋通贴膏治疗急性踝关节外侧副韧带Ⅰ、Ⅱ度损伤的临床观察%Clinical Observation of Lateral Collateral Ligament Injury of Ⅰ and ⅡDegree in Acute Ankle Sprain Treated with Liangxing Jingjintong Plaster
Institute of Scientific and Technical Information of China (English)
郭雪霞; 黄明喜; 沈钊雄
2016-01-01
Objective To observe the effects on lateral collateral ligament(LCL)injury of Ⅰ andⅡ degree in acute acute sprain treated with liangxing jingjintong plaster. Methods Ninety - two patients of LCL injury of Ⅰ and Ⅱ degree in acute acute sprain were randomized into a treatment group and a control group,46 cases in each one. In the treatment group,the external application of liangxing jingjintong plaster was used. In the control group,voltaren ointment was used in the local area. The clinical efficacy was observed in 14 days of treatment. Besides,Kofoed scale was used to score the ankle function. Results After treat-ment,the clinical efficacy and Kofoed score in the treatment group were better than those in the control group,indicating the significant differences(P < 0. 05). Conclusion Liangxing jingjintong plaster achieves the better efficacy on LCL injury of Ⅰ and Ⅱ degree in acute acute sprain and ankle function at the early re-covery stage. This therapy deserves to be promoted in clinical practice.%目的：观察凉性经筋通贴膏治疗急性踝关节外侧副韧带Ⅰ、Ⅱ度损伤的临床疗效。方法将92例确诊为急性踝关节外侧副韧带Ⅰ、Ⅱ度损伤的患者随机分为治疗组和对照组，每组46例。治疗组采用凉性经筋通贴膏外敷治疗；对照组采用扶他林软膏局部涂擦治疗。两组患者治疗14 d 后观察临床疗效，同时采用 Kofoed 踝关节活动度评分对踝关节功能进行评分。结果两组患者治疗后治疗组临床疗效及踝关节功能评分均优于对照组，两组比较差异有统计学意义（ P <0.05）。结论凉性经筋通贴膏对早期恢复急性踝关节外侧副韧带Ⅰ、Ⅱ度损伤患者的踝关节功能有较好疗效，值得临床推广应用。
16. Intra-observer reliability and agreement of manual and digital orthodontic model analysis.
Science.gov (United States)
Koretsi, Vasiliki; Tingelhoff, Linda; Proff, Peter; Kirschneck, Christian
2018-01-23
Digital orthodontic model analysis is gaining acceptance in orthodontics, but its reliability is dependent on the digitalisation hardware and software used. We thus investigated intra-observer reliability and agreement / conformity of a particular digital model analysis work-flow in relation to traditional manual plaster model analysis. Forty-eight plaster casts of the upper/lower dentition were collected. Virtual models were obtained with orthoX®scan (Dentaurum) and analysed with ivoris®analyze3D (Computer konkret). Manual model analyses were done with a dial caliper (0.1 mm). Common parameters were measured on each plaster cast and its virtual counterpart five times each by an experienced observer. We assessed intra-observer reliability within method (ICC), agreement/conformity between methods (Bland-Altman analyses and Lin's concordance correlation), and changing bias (regression analyses). Intra-observer reliability was substantial within each method (ICC ≥ 0.7), except for five manual outcomes (12.8 per cent). Bias between methods was statistically significant, but less than 0.5 mm for 87.2 per cent of the outcomes. In general, larger tooth sizes were measured digitally. Total difference maxilla and mandible had wide limits of agreement (-3.25/6.15 and -2.31/4.57 mm), but bias between methods was mostly smaller than intra-observer variation within each method with substantial conformity of manual and digital measurements in general. No changing bias was detected. Although both work-flows were reliable, the investigated digital work-flow proved to be more reliable and yielded on average larger tooth sizes. Averaged differences between methods were within 0.5 mm for directly measured outcomes but wide ranges are expected for some computed space parameters due to cumulative error. © The Author 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: [email protected]
17. Gypsum as a source of sulfur for strawberry cropsGesso agricola como fonte de enxofre para a cultura do morango
Directory of Open Access Journals (Sweden)
2013-09-01
in a randomized block design with three replications, with six doses of S: 0, 10, 20, 30, 40 and 50 mg kg-1 in the form of gypsum, and two doses of P: 300 and 600 mg kg-1 of P2O5. The Albion variety of strawberry plants was transplanted to pots and grown for 170 days. The fruits were harvested and weighed throughout the experiment; a similar procedure was followed for the shoots at the end of the experiment. The shoots and fruits were dried, weighed, ground, and analyzed for the content of S, Ca, and P. The production of strawberry fruits was influenced by S rates, with the highest productivity obtained by using S rates of 60 and 37 mg kg-1 with the application of 300 and 600 mg kg-1 of P, respectively.
18. The University Münster Model Surgery System for Orthognathic Surgery. Part II -- KD-MMS.
Science.gov (United States)
Ehmer, Ulrike; Joos, Ulrich; Ziebura, Thomas; Flieger, Stefanie; Wiechmann, Dirk
2013-01-04
Model surgery is an integral part of the planning procedure in orthognathic surgery. Most concepts comprise cutting the dental cast off its socket. The standardized spacer plates of the KD-MMS provide for a non-destructive, reversible and reproducible means of maxillary and/or mandibular plaster cast separation. In the course of development of the system various articulator types were evaluated with regard to their capability to provide a means of realizing the concepts compris | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6410039663314819, "perplexity": 10580.923032111179}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-43/segments/1539583512499.22/warc/CC-MAIN-20181019232929-20181020014429-00116.warc.gz"} |
http://mathoverflow.net/questions/17959/effect-on-connectivity-when-partitioning-a-graph/17995 | Effect on connectivity when partitioning a graph
I have a connected graph $G=(V,E)$, $V$ being the vertex set and $E$ being the edge set. I partition the graph into components $C=\{C_1,\dots,C_n\}$ such that all $C_i$ are pairwise disjoint.
Take two vertices $s,t \in V$ such that $s,t$ are connected by a path. Is there an $O(|V|+|E|)$ algorithm to find out the list of all $C_i \in C$ such that if we remove the vertices in $C_i$ from the graph, then $s$ will become disconnected from $t$.
I know there is the $O(|C|(|V|+|E|))$ algorithm to do so by removing vertices in $C_i \in C$ from the graph for all $1\leq i\leq n$ and then checking if $s$ and $t$ are connected.
This can be somewhat improved if we take all edge weights as 1 and compute the shortest path and then consider only components whose vertices are present in the shortest path but this still has worst case complexity $O(|C|(|V|+|E|))$.
-
Here is a thought: consider the color-adjacency matrix A_i, where (u,v)=1 iff u and v have a path using vertices only from at most i different partition classes, i running from 1 to n. Perhaps s and t have a path involving log(n) colors, and then the worst case for your shortest path algorithm would involve log(n) instead of n. You may get lucky and find an algorithm to compute, say, A_(2^j) quickly. Gerhard "Ask Me About System Design" Paseman, 2010.03.12 – Gerhard Paseman Mar 12 '10 at 9:04
Would A_i take $O(n^2)$ time to setup though? – Opt Mar 12 '10 at 9:09
It might. Even computing the row for vertex s might take some time. However, computing A_i for all pairs s,t might be useful in other applications. Gerhard "Ask Me About System Design" Paseman, 2010.03.12 – Gerhard Paseman Mar 13 '10 at 7:55
I am not sure if I get the point. Are there any restrictions on the components C_i? If there isn't any, then why not take all neighbors of s? – Sangxia Huang Mar 22 '10 at 12:37
You want a list of all the C_i, that's why just taking the neighbors does not suffice. – Opt Mar 22 '10 at 16:30
Consider the problem in which every "component" is a single vertex. Then the problem is to find every $s$-$t$ cutvertex in $O(|E|)$ time, which is fairly easy (each lies on every $s$-$t$ path).
If your components are not necessarily connected, it might be more difficult. You would have to solve the case in which each $C_i$ is an independent set. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8206678628921509, "perplexity": 329.65123650157443}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657104131.95/warc/CC-MAIN-20140914011144-00118-ip-10-196-40-205.us-west-1.compute.internal.warc.gz"} |
https://www.jiskha.com/questions/13314/a-4-kg-block-is-pushed-along-the-ceiling-with-a-constant-applied-force-of-85-n-that-acts | # PHYSICS
A 4 kg block is pushed along the ceiling with a constant applied force of 85 N that acts at an angle of 55 degrees with the horizontal. The block accelerates to the right at 6 m/s^2. determine the coefficient of kinetic friction between the block and the ceiling.
The applied force in the direction of motion is 85 cos 55 = 48.75 N
The friction force that acts opposite to the direction of motion is
(F sin55 - M g)* (mu,k)
To solve for (mu,k), the coefficient of kinetic friction, solve the Newton's Second Law equation
Fnet = F cos55 -F sin55 + M g(mu,k]
= M a
You already know F, M, g and a.
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3. 4.00 kg block is pushed along
the ceiling with a constant
applied force of 85.0 N that acts
at an angle of 55.0° with the
horizontal, as in the figure. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between the block and the ceiling.
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4. 4.00 kg block is pushed along
the ceiling with a constant
applied force of 85.0 N that acts
at an angle of 55.0° with the
horizontal, as in the figure. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between the block and the ceiling.
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http://volokh.com/posts/1142373636.shtml | pageok
pageok
pageok [Puzzleblogger Kevan Choset, March 15, 2006 at 11:16am] Trackbacks The West Wing & Math: This dialogue is from the West Wing episode, "Evidence of Things Not Seen." C.J. There's a spot on the earth where the temperature is exactly the same as it would be if you drilled through the earth to the other side. WILL No, there isn't. How about six dollars if you do it with a face card? C.J. Yes, there is, and it's called the antipode. And if that's true, then why can't it be that you could stand an egg on end at the equinox? Now, the problem. Prove that at any given moment, what C.J. is saying is true: there are two points on the earth exactly opposite each other which have the exact same temperature. You can assume that temperature is continuous (i.e., there's no spot on the earth where the temperature just "jumps" from 0 degrees at one spot to 100 degrees at a spot infinitesimally close to it). (link) Aaron Bergman (mail): Ah, the joys of the intermediate value theorem. 3.15.2006 12:18pm (link) Very Anonymous Coward: Suppose not; then construct the obvious retraction; Brouwer fixed point theorem; contradiction. A related result is that there is at least one place on the Earth where there is no wind. 3.15.2006 12:44pm (link) Freder Frederson (mail): With what precision are you measuring the temperature. If you are measuring the temperature with sufficient precision, I would imagine the statement is never true. If you are measuring it within a degree or two then I would imagine it is often true if you are looking at the tropics over the oceans and in temperate zones during spring and fall. 3.15.2006 12:47pm (link) Anoymous Koward: There are probably serveral points on the equator where that's true. So what is her point? 3.15.2006 12:49pm (link) Anoymous Koward: Except that when it's daytime on one side, it's night on the other. So maybe not. 3.15.2006 12:52pm (link) Kevan Choset (mail): Very Anonymous Coward -- that all sounds fine, but would you care to explicate? Freder Frederson -- no matter how precisely you measure, it will always still be true. Anonymous Koward -- maybe it's true on the equator and maybe it's not. But unfortunately that doesn't a proof make... 3.15.2006 12:59pm (link) Kevan Choset (mail): (And for those of you turned off by the math, I promise you don't need anything complicated. As for the Intermediate Value Theorem, you don't need anything more sophisticated than the fact that if it's 0 degrees in NY and 10 degrees in Boston then it must be 5 degrees somewhere between them. (And 4 degrees somewhere between them, and 9.99 degrees somewhere between them, and pi degrees somewhere between them, and 0.[TheNumbersFromLost] degrees somewhere between them, etc., etc.) 3.15.2006 1:01pm (link) HeScreams (mail): I haven't wrapped my head around the proof yet, but I'm certian that this spot has never been in my kitchen. Koward: on the equator, it's always dusk somewhere, and it's dawn on the other side. At those spots it's at least possible that they have the same temp; but the problem is actually mathematical. Freder: actually, you have it backwards. A lack of precision would allow the statement to be false; with sufficient precision the statement is always true (assuming it's ever true). 3.15.2006 1:03pm (link) Robert Cote (mail) (www): Temperature is not a discrete number. All you need is two antipodes with daily highs and lows where one place has a higher high and lower low and sometime during that day their temeperatures passed each other. Duplicate except hold temperature is held constant and location is varied. Is this some kind of test? What did I win? 3.15.2006 1:12pm (link) A. Zarkov (mail): Very Anonymous has got it. The key assumption is continuity of the temperature field. But we need to prove it and my topology is rusty. 3.15.2006 1:20pm (link) JLR (mail) (www): This is technically not a "proof," but there aren't too many places where land-to-land antipodes are even possible. For example, I believe that anywhere in the lower 48 states, if you "drilled a hole through to the other side of the earth," you'd hit the Indian Ocean. About four-fifths or so of Earth's land is antipodal to water. However, I believe parts of Argentina and Chile are antipodal to China. Also, I believe parts of Norway are antipodal to Antarctica. Furthermore, if memory serves me, parts of Spain are antipodal to parts of New Zealand as well. 3.15.2006 1:22pm (link) Aaron Bergman (mail): I'm not sure what the Brouwer fixed point theorem has to do with this. Just pick a diameter of globe. Pick some plane through the center of the earth to rotate it around. Let f(theta) be the difference in the tempreatures between the two antipodes. Then it's clear that f(theta + pi) = -f(theta). So, the intermediate value theorem tells us that there's a value of theta between zero and pi such that f(theta) = 0. QED. 3.15.2006 1:26pm (link) Dan Levine (mail): Kevin, it has to be true around the Equator. Just as it has to be true that there is a place on the Arctic Circle where directly across the Arctic Circle (not going through the center of the Earth) the temperature is the same. 3.15.2006 1:27pm (link) James Grimmelmann (mail) (www): Consider just the equator. For each point on the equator, consider the difference in temperature between that point and the point directly opposite it (more precisely, the temperature at that point minus the temperature directly opposite). If this difference-function is zero for every point on the equator, then we're done -- any two opposite points have the same temperature. If the difference-function is nonzero at some point (call it A), then the difference-function is the negative of that nonzero value at the exact antipode of A. Consider the segment of the equator from A to A's antipode. The difference-function goes from some positive value to the negative of that value as you go along the segment. At some point along the segment, the difference-function must be zero. That point and the point directly opposite it have the same temperature. 3.15.2006 1:31pm (link) Dan Levine (mail): I like James's proof. Here's a graphic way to think about it. Let the x-axis refer to degrees around a circle. Let the y-axis refer to temperature. Draw any continuous graph that crosses the x-axis at (0,0) and (360,0)--the idea being that when you make it all the way around the circle and wind up at the same point the temperature is the same. Now draw the same-shaped graph shifted over 180 degrees to the right---i.e., the same shape, but crossing the x-axis at (180,0) and (540,0). At any point where the two graphs cross, there will be a point on the first graph, 180 "degrees" to the left, that has the same y-value (i.e., the same temperature). 3.15.2006 1:48pm (link) SLS 1L: This is slightly less obvious to me, because I don't remember the relevant bits of calculus very well, so I'm going to have a go at it by intuition. If it's true in the following one-dimensional case, then it's true on the earth as well: Consider two points A and B at opposite ends of the earth and any "equator" defined by them. Let t(theta) be the temperature at the point theta radians from A along that circle (so t(0) = t(2pi) = the temperature at A and t(pi) = the temperature at B). The claim in this one-dimensional case is that there is a point theta0 such that t(theta0) = t(theta0 +- pi). If t is constant, then the claim is true and we are done. If t is not constant, then it has at least one maximum or minimum. Let theta0 denote any such maximum or minimum; since t(0) = t(2pi), t(theta) must take on every value between t(0) and t(theta0) at least twice. Here's the non-rigorous graphical intuition element of the proof. Graph f(theta) on a standard cartesian graph (with theta on the "x-axis" and f(theta) on the "y-axis") from 0 to 2pi. Imagine a line segment of length pi parallel to the theta-axis "moving" along the function's curve starting at theta = 0 and and ending at theta = pi (i.e. the line segment runs from (theta, f(theta)) to (theta + pi, f(theta))). By graphical intuition, you can see that at some point theta' in this process both ends of the line segment must intersect the curve of f. Since the line segment is pi long, this means that f(theta') = f(theta' + pi). Since we have proved that the theorem holds along every equator of the earth, it is true on the earth itself. Q.E.D. 3.15.2006 1:53pm (link) FXKLM: I think CJ is wrong about the egg thing though. And even if s/he is right, is it in any way related to the antipode? 3.15.2006 1:54pm (link) SLS 1L: I see several people have posted the same intuitive idea in a less complicated way while I was writing mine. I like Dan's best. 3.15.2006 1:55pm (link) Gavin Peters (mail): Ok, so any great circle has two antipodal points at the same temperature on it. That's boring first year analysis stuff. Here's the real question: demonstrate that on the earth there are two antipodal points with the same temperature _and_ pressure! 3.15.2006 2:10pm (link) LTEC (mail) (www): Coward -- I think you are making this too difficult. As the above arguments show, this works on any circle, that is, in two dimensions. Your argument about (essentially) not being able to comb a hairy coconut only holds in three dimensions, since we can comb a hairy circle. 3.15.2006 2:14pm (link) Philip S: Consider just the equator. Let the temperature fcn. at time t be defined as f ranging from 0 to 2pi. If f is constant the result is trivial. If f is not constant define f over the whole real line periodically in intervals of 2pi. Now define g(x) = f(x) - f(x+pi). f is continuous by assumption, and since g is the difference of two continuous fcns. it too is continuous. Since f is continuous but not constant, therefore g must have both pos. and neg. values. Since g is also continuous, therefore there exists x s.t. g(x) = 0. QED 3.15.2006 2:16pm (link) Philip S: whoops. Instead of "Since f is continuous but not constant" I should have written "Since f is continuous, periodic, and not constant." I think that should do it. 3.15.2006 2:21pm (link) Siona Sthrunch (mail): In fact, there are antipodal points on the earth that have the same temperature and barometric pressure. Let T be a temperature distribution on the earth and let U(T) be the set of points whose temperature is the same as their antipodal points. We know from the comments above that U(T) intersects each great circle on the earth. Of course U(T) is symmetrical. In general, what properties are sufficient for a set S on the earth's surface to equal U(T) for some T? 3.15.2006 2:23pm (link) rbj: Perhaps the Arctic after 6 months of winter and the Antarctic after 6 months of summer? Or a spot on the equator during sunrise and sunset? I have absolutely no way of proving these. 3.15.2006 2:25pm (link) Jim T: I don't think that you are reading the quote correctly. Her first sentence is: "There's a spot on the earth where the temperature is exactly the same as it would be if you drilled through the earth to the other side." You could obviously say that she (or the writers) mis-spoke, but what she is claiming has absolutely nothing to do with two spots on either side of the Earth. She is saying there is some point on the Earth's surface, let's call it 'X', at which the temperature would be completely uneffected if a hole were to be drilled through the Earth all the way to the other side. It seems to me that such a hypothetical hole would have to have SOME effect, though I suppose that would depend on it's radius. I also don't see how such a thing could be proven or disproven. 3.15.2006 2:45pm (link) Kevan Choset (mail): Dan, Yes, it's definitely true on the Equator. (It's definitely true on any circle, in fact.) But I believe the earlier suggestion about the Equator was trying to rely on some sort of special temperature-related properties that are true on the Equator, which I was trying to discourage. 3.15.2006 2:49pm (link) Kevan Choset (mail): James's solution was the one I had in mind. You can actually view the whole earth instead of just the equator, but use his trick of looking at the difference between the temperature of every point on earth and the point completely opposite it. This is, of course, still a continuous function. It can't be positive everywhere (because if it's positive in NY then it's negative in the point directly opposite NY), and similarly can't be negative everywhere. So it's positive in some places and negative in others. This means that it must be 0 somewhere. Wherever it's 0, the temperature is the same at two opposite points. 3.15.2006 2:54pm (link) Aaron Bergman (mail): There might be an easier way to do the pressure/temperature thing, but I came up with this (which is essentially an obstruction theory argument). For p a point on the sphere and -p its antipode, define the function f(p) = (T(p) - T(-p), P(p) - P(-p)) This is a map from S^2 into R^2. Assume that it never hits the origin. Then we have a map into R^2 \ {0}. We also have that if (x,y) is in the image of f, then so is (-x,-y). Since the image of f is also connected, it contains a (non-contractible) circle that goes around the origin. Take the inverse image of this circle. This gives a region on S^2 that contains a circle which maps to the circle around the origin of R^2. However, any circle on the sphere can be "filled in" (ie, the sphere is simply connected). Apply f to this disc. It must map to a contractible region bounded by the unit circle in R^2 \ {0}. No such region exists, so we have a contradiction. Thus the image of f must include the origin. 3.15.2006 3:03pm (link) Tennessean (mail): Is there any sense to the assumption that temperature is continuous? Maybe there is; certainly, it makes sense to assume that there is no place where the temperature is 0 immediately next to a place where the temperature is 100. But if you assume, as I think we are, that the notion of place is not necessarily continuous (i.e., temperature is a measure of a discrete place or field), then why would temperature be continuous? 3.15.2006 3:07pm (link) Juan Notwithstanding the Volokh: You can assume that temperature is continuous (i.e., there's no spot on the earth where the temperature just "jumps" from 0 degrees at one spot to 100 degrees at a spot infinitesimally close to it). But this is not a safe assumption. Take, for instance, a lava flow or an iceberg. It is possible that the temperature may well jump or drop by 100 degrees from one point to the next. More mundanely, it depends on how you measure "on" the earth. A cliff may have a particular temperature at it's edge, while the next "spot on the earth", which is "infinitesimally close" for the purposes of determining an antipode could be the ocean below, with a significant rise or drop in temperature due solely to the change in altitude. Maybe you live on a perfect sphere, but my planet is more interesting. 3.15.2006 3:20pm (link) John (mail): There are an infinite number of such points. Connect any two points that are at the two ends of a diameter of the earth. Assume they are of different temperatures. Now rotate the diameter line until the ends are reversed. As each point was traversing the temperature range from what it started at to what the other end started at, the two temperatures must, at some point be the same. 3.15.2006 3:27pm (link) exfizz (mail): Let C be a great circle (e.g. the equator) on the sphere S. Let L=[0,360] be a parameter that functions as a generalized longitude on C. Let T(L) be the temperature (or any continuous scalar field) on S. Let d(L) = T(L)-T(180-L) be the difference between temperatures at L and its antipode L'. Since d(L)=-d(L'), the intermediate value theorem says there must exist at least one Lo for which d(Lo)=0, i.e. for which T(Lo)=T(Lo'). The choice of equator was arbitrary; the proof holds for any great circle, or indeed any circle or any closed loop on the surface of S. It's just that the tidy notion of "antipodes" becomes less tidy in that case. (For me, the fixed point theorem comes into play when I visualize the problem: a closed loop with a rising and falling line above it. Rotate the loop 180o, i.e. map it onto itself. There must be at least one spot where the two lines cross.) 3.15.2006 3:51pm (link) lpdbw: I have personally balanced an egg on end during an equinox. Being a scientist, I repeated the experiment every day for 10 days. It's a matter of eggs and steady hands, and the equinox is irrelevant. I don't watch that TV show, and the comment by "Will" makes no sense to me. There must be some context missing... 3.15.2006 3:52pm (link) exfizz: Juan Notwithstanding the Volokh: [it] is not a safe assumption [that temperature is continuous]. Take, for instance, a lava flow or an iceberg. It is possible that the temperature may well jump or drop by 100 degrees from one point to the next. Below the distance scale of the mean free path (~0.1 μm in room air), it is true that the continuity of the T field gets a little dicey, but (1) I think you can still define it using the KE of an individual molecule, and (2) outside of a physics lab you will not find a temperature measuring device capable of resolving at a distance scale and a time scale where this matters. Besides, even a lava/air system or ice/air system has a transition layer where temperatures match up. Maybe you live on a perfect sphere, but my planet is more interesting. I realize you're joking, but (I think) the result holds for any closed loop on any surface equivalent to a sphere, including our beloved lumpy home. And far from reducing reality to a bland abstraction, math and science IMHO reveal aspects of its richness in a way that other ways of seeing do not. 3.15.2006 4:18pm (link) eng: The trouble is the phrase "through the Earth" which can quite reasonably be taken as through the center of the Earth. If you make such a restriction that there must be a line passing through the center of the earth, then it is false that there must be a pair of points on the perimeter intersecting such a line that are of equal temperature. It is only once the statement is relaxed to mean "any straight tunnel" that we can be assured of finding a solution. 3.15.2006 4:19pm (link) SLS 1L: eng:It is only once the statement is relaxed to mean "any straight tunnel" that we can be assured of finding a solution.I don't quite follow. If you consider e.g. my "proof" above, I think it's clear that any great circle has two points of equal temperatuer separated by pi radians - i.e. on opposite sides of the earth. I am hardly 100% confident of my reasoning or anyone else's here, but can you explain? 3.15.2006 4:28pm (link) james tierney (mail): Eng-- CJ's quote doesn't require that it hold true for every (any?) point. Rather, she says that there is "a spot on the earth" for which this will be true, given that the line in question is through the center of the earth. If the spot is on the equator, runs through the center of the earth, and hits the equator on the other side, there is probably a solution (as other posters have pointed out). 3.15.2006 4:31pm (link) Siona Sthrunch (mail): For p a point on the sphere and -p its antipode, define the function Bergmann - The first error in your proof is that it is not the case that a symmetric connected set in R^2 not containing the origin necessarily contains a circle. Bergmann wrote: Since the image of f is also connected, it contains a (non-contractible) circle that goes around the origin. 3.15.2006 4:32pm (link) DK: The temperature _is_ continuous, although this gets into physics, not math, and you have to measure very precisely. In any medium allowing heat diffusion, diffusion instantly smooths any transient heat discontinuity into a continuous but initially steep shape. Thus, if you have a magic wand that can create a temporary temperature discontinuity, the discontinuity will vanish right way. Moving objects and the differences between materials complicate things, but to simplify, just replace "the earth" with "the atmosphere X meters above all buildings, ground, moving objects, and near-ground heat sources". The same argument applies to that layer of atmosphere. 3.15.2006 4:39pm (link) Jam (mail): http://en.wikipedia.org/wiki/Antipodes In geography, the antipodes (from Greek anti- "opposed" and pous "foot") of any place on Earth is its antipodal point; that is, the region on the Earth's surface which is diametrically opposite to it. Two points which are antipodal to one another are connected by a straight line through the centre of the Earth. At any given moment half of the Earth surface is absorbing energy (daytime) and the other half is releasing energy (nightime). The temperature will be the same at the point of equilibrium; where a spot has gained energy and it's antipode has released energy. Antipodal equilibrium will happen: 1) At noon when the rate of energy absorption and release are the same. 2) Towards sunset if the rate of energy absorption is faster than the rate of energy release. 3) Towards sunrise if the rate of energy absorption is slower than the rate of energy release. 3.15.2006 4:49pm (link) Tennessean (mail): As an uneducated remembrance, it was my impression that temperature and pressure were closely related, and that pressure was a sampled statistic of a point _oer time_ used to "represent" an area. Also, although there is diffusion, it is not clear that this is an instant process. In light of these three assertions, is temperature necessarily continuous? (Not that this in any impugns the solutions offered to the actual problem posed - just an aside that seems interesting from here.) 3.15.2006 4:59pm (link) Juan Notwithstanding the Volokh: exfizz: But how would you account for cliffs and the like where an altitude difference might result in a significant temperature difference between two points that are adjacent for purposes of determining their antipode? JNOV 3.15.2006 5:34pm (link) Philistine (mail): Maybe I'm just confused, but isn't it pretty trivial to find counterexamples to the contention that there would mathematically always be an antipode with equal temperatures? Take the equator example. Picture the equator as a clockface--from 12 to 2 on the clockface (i.e. for 60 degrees of a circle)it is 100 degrees fahrenheit. At 2, it changes to 105. At 6 (180 degrees) it changes to 115 and at 7 is 110, and remains there until 11 when it goes back down to 100, returning to 100 at 12. It makes more sense is you draw it on a piece of scrap paper. :) There do not seem to be two antipodal points with the same temperature. 3.15.2006 6:09pm (link) SenatorX (mail): I think John is right and there are an infinite number of points. Basically that if the condition to refute is " there are two points on the earth exactly opposite each other" it infers that there are two points that share a common midpoint. This midpoint defines two equal lines. Now the condition "on the Earth" is ambiguous. But it clearly infers that any place "on the Earth" is fair game to satisfy the condition. Since the Earth is "sphere like" and further no condition AGAINST rotating the lines around the common midpoint exist... We define the possible range of probabilities as the area of a perfect sphere. Further though is "on the Earth" which contrast to "under the earth" or "above the earth" infers an area as infinitely as close to being "on the Earth" as possible. Let us decide as a tightest possible condition this area. People think of the equator because the greatest chance of similar variables would occur to produce the same temperatures. Temperature is the final condition and so this is a valid source of points but not limited to as the asymmetrical nature of "the Earth" is a factor. We have now defined the area that the matching temperature points could exist by refuting the any possible area where they could not exist. We do this at an infinite level because the statement to prove allows this. The places where the points can occur have extreme conditions BUT they are infinite because the movement of two points around a common point allows for infinite possibilities of success when MEASURING is the judge of success. Measuring can be as accurate as necessary, infinitely. So measuring temperature can in finely succeed at refinement(or grossness). Basically because of "on the Earth", "two points exactly opposite", and a measurement(temperature) the condition to prove contains many infinites and so an infinite number of successful conditions can occur if only one condition of success can occur. 3.15.2006 6:21pm (link) Jadagul (mail) (www): Juan notwithstanding the Volokh: since no cliff will be perfectly verical, there will always be some slope and thus a smooth gradient. I guess you have to assume that the earth's surface is relatively smooth (sorry, I'm sure there's a technical term for this and I'm sure I'll know it by the end of the semester when I finish my topology course). Philistine: we assumed that the temperature was distributed continuously. You have four points of discontinuity there, which is why it doesn't work. But physically, you can't have a discontinuous temperature field for a non-infinitesimal duration. 3.15.2006 6:29pm (link) Kevan Choset (mail): Philistine- Nope, it's not pretty trivial to find a counterexample, since there are no counterexamples! In the case you describe, the antipodes will be between 2 and 6 and between 7 and 11. Between 2 and 6 the temperature changes from 100 to 115 and between 7 and 11 the temperature changes from 100 to 110. Somewhere in there, the points opposite will have the same temperature as each other. 3.15.2006 6:34pm (link) Philistine (mail): Kevan Choset In the case you describe, the antipodes will be between 2 and 6 and between 7 and 11. Between 2 and 6 the temperature changes from 100 to 115 and between 7 and 11 the temperature changes from 100 to 110. Somewhere in there, the points opposite will have the same temperature as each other. I still don't see it. In my hypothetical, there could be equivalent antipodal temperatures--but only coincidentally. The vast majority of situations would not have them. For instance--keep my hypothetical, but refine it. All temperature changes are not "instantaneous" but occur in the 1 minute (6 degrees of the circle) before they are given. (Thus from 100 to 105 occurs just before 2, 105 to 115 just before 6, 115 to 110 just before 7 and 110 to 105 just before 11. If this is the case, I don't see antipodal equivalents. Am I missing something? --Philistine 3.15.2006 7:05pm (link) Kevan Choset (mail): Philistine-- In your refined example, it is 105 degrees at both 11:00 and 5:00, which are antipodal. You can change your setup to avoid this problem, but it will create another problem. The beauty of a mathematical proof (like James's, above) is that we don't have to worry about trying lots of different examples, since his logic holds for all possible examples. 3.15.2006 7:28pm (link) Dr. T (mail): I do not believe that any of the given math proofs work. They make too many assumptions about the physics of temperature distributions that are not true. They assume that because one spot is temperature A and its antipode is temperature B, the difference A-B can be brought to zero by rotating around a plane that passes through the center of the earth. As others have noted, this assumes no temperature discontinuities. The only way that we can guarantee no temperature discontinuities is if we assume that the spots at which temperatures are measured are infinitely small, a physical impossibility (because temperature requires moving molecules, and molecules have size). Another false assumption is that the A-B difference as we rotate around the bisecting plane is linear. Why should it be? If the gradient is non-linear, then there may never be a place where the antipodal temperature difference is zero. 3.15.2006 7:58pm (link) SLS 1L: Dr. T - if I understand the physics correctly, temperature becomes undefined, not discontinuous, when you try to consider it on a small enough scale. But continuity is a reasonable physical approximation. As for your claim about the A-B difference, t(theta) (the temperature at angle theta along a given great circle as we rotate around the circle) is a continuous function. So is t(antipode(theta)). Since both are continuous, t(theta) - t(antipode(theta)) is also continuous. If t is nonconstant, then the difference is positive at some point and negative at some other point, and by the intermediate value theorem it must take on the value zero at some point. No assumptions about linearity are required. 3.15.2006 8:13pm (link) Tennessean (mail): SLS - Concedering arguendo that temperature becomes undefined when you try to consider it on a small enough scale (i.e., for a point as opposed to for a volume), why would you assume that "continuity is a reasonable physical approximation"? (Again, this is not to detract from the elegance of the proof adduced above by many.) 3.15.2006 8:21pm (link) The Real Bill (mail): I think uniformity is required as well, not just continuity. 3.15.2006 8:25pm (link) The Real Bill (mail): Nope, uniformity is not required. 3.15.2006 8:49pm (link) SLS 1L: Tennessean - few, if any, physical quantities that we treat as continuous without running into problems are actually continuous. Charge is quantized, but that doesn't mean "charge is continuous" is a bad physical approximation. Basically the same point holds for temperature. 3.15.2006 9:02pm (link) Tennessean (mail): SLS: The normative judgment "bad physical approximation" is appropriate or inappropriate depending on the context, obviously, and, for many purposes, the assumption of continuity renders feasible many calculations and understandings with few errors or other problems. Here, however, the proofs all depend on the fact of continuity. So, it is a reasonable to question to ask. Just saying that it is a good assumption does not make it so (especially where we've already discussed that temperature is a statistic, not an attribute, as far as the temperature of a particular point at a particular time). 3.15.2006 9:21pm (link) Dick King: Some cliffs are overhung [so when you climb them you are holding yourself on with your hands]. In that case, there is a particular latitude and longitude that has three or more points. -dk 3.15.2006 9:56pm (link) Aaron Bergman (mail): Siona: By connected, I meant path connected. Sorry. Let U be a path connected subset of R^2 \ {0} s.t. if p \in U, then -p \in U. Pick a point p. Then, by assumption, there exists a path q(t) in U s.t. q(0) = p and q(1) = -p. Define the following path r(x) = q(2x) for x \in [0,1/2] r(x) = -q(2x - 1) for x in [1/2,1] By assumption again, r(x) is in U. It's easy to see that r is continuous and that r(0) = r(1), so it is a circle. It can be seen to be noncontractible in R^2 \ {0} by looking at polar coordinates, for example. 3.15.2006 9:57pm (link) Siona Sthrunch (mail): Bergman writes: It's easy to see that r is continuous and that r(0) = r(1), so it is a circle It is not true that r must be a circle. For example, r could be an ellipse, correct? Or any closed antipodally symmetric loop. 3.15.2006 10:06pm (link) SenatorX (mail): From the "problem" :"You can assume that temperature is continuous (i.e., there's no spot on the earth where the temperature just "jumps" from 0 degrees at one spot to 100 degrees at a spot infinitesimally close to it)." So let’s leave out of it the "real" world for the sake of the conditions in the problem to solve. I don't have a problem with the mathematical proof given so far for opposite points from an equal midpoint. Dr.T adds some excellent points I think. The thing is (and I wish someone could put this in mathematical terminology for me) that proving that is not enough. The problem calls for equal temperatures as well as antipodes. The problem calls for a cross correlation of "same area" between the math proof given for the equidistant points AND the ranges where the temperatures are the same at any given instant. It is worth noting that it doesn’t say the antipodes(as far as space-time are concerned)must remain in any sort of continuity. They could exist in any of possible area that the conditions are able to be satisfied in at any given instant. I think the key to the problem is given in the final statement about the temperature being continuous. It then even defines continuous for us by saying you cannot find a place to measure temperature, "at no spot on the earth", where a "spot infinitesimally close to it" has a non-continuous jump of value. What does this mean if not that two points(or the range of area defined by the points in the surface of a sphere intersecting with the surface of the earth) are connected by a continuum of temperature? That you can not MEASURE any two spots "infinitesimally close", or more to the point, any two points NOT that close(range of min/max variable in earth topology) without finding a gradient of values between the two points. It doesn't just jump from 0 to 100, 25 to 75, or anything to any other thing without being able to MEASURE a gradient between the two points in space. I am sure there is a mathematical way to formulate this. To me it means since there are an infinite number of gradients between two points equidistant from each other then measuring for value in those gradients(temperature) can give infinite results. Somewhere in infinity will be a matching condition at any given instant? I also think you would never be able to prove this type of "problem" by observation of nature. It's mostly mental masturbation. 3.15.2006 10:07pm (link) Aaron Bergman (mail): Sorry. I was speaking loosely. Read "loop" where ever you see "circle". 3.15.2006 10:37pm (link) Lev: Antipodes, islands, New Zealand - rocky uninhabited islands, 24 sq mi (62 sq km), South Pacific, c.550 mi (885 km) SE of New Zealand, to which they belong. Explored by British seamen in 1800, the Antipodes are so named because they are diametrically opposite Greenwich, England. Prove to me that Greenwich and The Antipodes never have the same temperature. 3.15.2006 11:19pm (link) exfizz: Lev: "Prove to me that Greenwich and The Antipodes never have the same temperature." That's a fun example, Lev, and contra SenatorX, easy to investigate. Considering that air temperature is a roughly periodic function (strong components at 1d-1 and 1y-1) varying widely about the mean, and that antipodal points share the same solar warming (just 180o out of phase), I'd wager that TG(t)=TA(t) many times each year. (Of course, applied to the proxy data below the IVT guarantees at least twice/year.) It won't happen tomorrow. Using proxies for the Antipodes, tomorrow Auckland will range from 52-71 and Wellington from 54-68, vs. London only from 37-42; thus the ranges are disjoint. But April-June and again September-October the monthly average temperature ranges overlap significantly and we might expect to see TG(t)=TA(t) more often. A simple "bot" could scrape the weather pages repeatedly and compare temps during those months. Good project for a smart HS kid. Appendix: Monthly avg temp for Wellington, NZ / London, UK Jan 58-67 / 33-44 F Feb 57-67 / 33-45 Mar 56-65 / 35-50 Apr 53-61 / 38-55 May 49-56 / 43-61 Jun 46-53 / 49-67 Jul 45-51 / 52-71 Aug 45-52 / 52-71 Sep 47-55 / 48-66 Oct 49-57 / 44-59 Nov 51-60 / 37-50 Dec 55-64 / 34-46 3.16.2006 2:47am (link) Daryl Herbert (www): I agree with Kevan that James' explanation was best, and I think Kevan's illustration is best. "If the difference-function is nonzero at some point (call it A), then the difference-function is the negative of that nonzero value at the exact antipode of A." I missed that insight, which makes his solution much more elegant than mine. I proved it by showing that: 1 if your difference function ever returns 0, then the points match 2 if it's always negative, that means temp always decreases as you go around the circle, but that's no good because if you go around and around multiple times it keeps getting colder--but at 0* it must be the same temperature as at x* when x approaches 360. 3 if it's always positive, that means that means the temp always increases as you go around, with the same problem. 4 if it's both positive and negative at times, then it must pass through the origin (be equal to zero at some place), because it is continuous. (this is where the Mean Value Theorum actually comes into play) But my proof is better, because it can be expanded to show to show that for ANY continuous cyclical path with continuous temperatures, for ANY distance between the two points (not necessarily "halfway" but 10%, or 10 miles, etc.) you will be able to find some two points that satisfy the distance requirement AND are at equal temperature. So there :-) 3.16.2006 4:21am (link) BobGo: So much nonsense is inspired by asking for a mathematical proof. Only Philistine seemed to appreciate that day/night and winter/summer real-world variations make it improbable, though not impossible, for temperatures at antipodes to be equal. On the equator, early morning and early evening could have equal temperatures, but only if heating and cooling were exactly symmetrical and local weather didn't interfere. In the tropical and temperate zones it would be possible that a winter daytime temperature would equal a summer nighttime temperature, but given the scarcity of antipodal land areas, variations of elevation, and local weather conditions, a rare coincidence. Let's try the polar regions: thick icecaps provide good insulation, probably even from extreme seasonal variations, though no guarantee against geothermal variations. Jim T's interpretation of CJ's original assertion is the cleanest answer: the temperature at a spot on the Earth would be unaffected by drilling (figuratively) through to the other side. 3.16.2006 6:33am (link) AppSocRes (mail): By definition the "antipode" of a point on a sphere is the point defined by the intersection of a line through the original point and the center of the sphere and the surface of the sphere and that is not the original point. All arguments using the Intermediate Value Theorem, Mean Value Theorem, Rolle's Theorem or any variation just show that at least two points on a circumference of a sphere have the same value for any continuous function mapping the surface of the sphere to the real number line. None of these proofs demonstrates that these two points are antipodes except in very special cases. The property everyone is attempting to prove is a global property of the sphere and dependent on the sphere's topology. What everyone's trying to prove must be a corollary of the Brouwer Fixed Point Theorem: probably a proof by contradiction involving a constructed pull-back function. I don't have time to work out the details. By the way, there is an elementary introduction to category theory -- a mathematically inclined high school student could handle it -- that contains a proof of the fixed point theorem using only category theory. Very neat stuff. I didn't see a proof of Brouwer's theorem till my junior year at university. 3.16.2006 8:25am (link) Aaron Bergman (mail): None of these proofs demonstrates that these two points are antipodes except in very special cases. I'm too tired to check if all of the proofs demonstrate this, but the majority of them definitely show that the antipodal temperatures are equal. 3.16.2006 10:59am (link) AppSocRes (mail): I was wrong. Aaron Bergman has convinced me the Mean Value proofs work. 3.16.2006 2:03pm (link) Robert Ayers: Aaron Bergman et all have the fine proof that involves picking a pair of points A and A*, seeing that they do not satisfy T(A) == T(A*), then rotating the diameter until A goes to A* and A* goes to A. It is amusing that the same proof applies to this puzzle: Given a true chair and a warped floor (continuous and with some requirements on max error) show that you can positon the chair so it won't wobble. Bob Ayers 3.16.2006 2:33pm (link) Jam (mail): The Earth is tilted, so that the poles are in complete darkness or complete light at certain times of the year. The only times that the poles may have the same temperatures is when the Earth's tilt is tangental to the Sun -- this happens twice a year. 3.16.2006 9:24pm (link) Siona Sthrunch (mail): Bergmann wrote: Sorry. I was speaking loosely. Read "loop" where ever you see "circle". The current version of your proof (of Borsuk-Ulam) is still either malformed, substantively incorrect, or both. It's malformed because you wrote in an earlier draft "unit circle" and there is no "unit loop." Frankly, the logic of your proof is still not written clearly, although it does use many standard mathematical terms. It's substantively incorrect, to the extent that I can analyze its nonstandard terminology, because there is a continuous map from S^2 onto the unit circle in R^2, which sends an equator onto the unit cirle, and the unit circle is of course antipodally symmetric. I believe the point of your proof may have been that there is no such map, since your construction of the map f:S^2->R^2 from the vector field on S^2 has only the named properties, and yet is in fact existent, contradicting your analysis. 3.16.2006 11:13pm (link) Siona Sthrunch (mail): Also, Bergmann, I am only picking on you because you seem to be one of only about 5% of the posters on this thread who do not clearly have no idea whatsoever what mathematics or a mathematical proof even is; the remaining 95% of the posts cannot even be discussed. 3.16.2006 11:17pm (link) Siona Sthrunch (mail): AppSocRes wrote: By the way, there is an elementary introduction to category theory -- a mathematically inclined high school student could handle it -- that contains a proof of the fixed point theorem using only category theory. I would be curious to see this since the fixed point theorem depends on the topology of R^n. Brouwer does usually come from the homology or homotopy chain functors (assigning sequences of groups to embeddings of topological spaces); I don't see how this can be replicated at a high-school level using category theory. 3.16.2006 11:21pm (link) Oren (mail): I had no idea so many other math people read the VC! /feels a little better now 3.17.2006 4:13am (link) BobGo: Exfizz has nicely shown, with his temperature range comparisons for NZ and UK, that there are overlaps in late spring and early fall, with the likelihood of equal temperatures twice daily during those seasons. Not very likely during the rest of the year, however. And even during the overlap seasons, not at just any moment; you have to wait for the varying times when the temperature lines cross. There are a few other antipodal places on Earth where such seasonal temperature range overlaps could occur, but antipodal land areas are quite sparse. I am assuming we are limited to land areas because “antipodes” means “feet growing out of heads” (as necessary for walking down under), and feet are for walking on land, aren’t they? So you’d have to look pretty hard for antipodal equal temperatures during much of the year, except maybe in the polar regions. Is the proposed problem intended to apply to any pairs of opposite points on the globe, whether land, water, mountains, or icecaps? It would take a lot more investigation to look for daily temperature range overlaps between water/water opposite points and water/land opposites points. Opposite-point equal-temperature moments might be quite common in some seasons, But do they occur somewhere “at any given moment”? I can’t say for sure, and there is little in the comments that is even remotely relevant. It’s amazing to me how little the math discussion in these comments has to do with understanding of seasons and weather conditions on a real Earth. 3.17.2006 5:56am (link) Very Anonymous Coward: Siona Sthrunch: Perhaps it's just for the 2-dimensional case? There are a number of cute ways of proving it that don't require very much machinery at all: Sperner's lemma, the game of Hex, some easy covering space arguments to get the fundamental group of the circle, etc. 3.17.2006 6:51am (link) Very Anonymous Coward: AppSocRes: Yes, that was my first impression as well. But I agree now; the IVT is all you really need. 3.17.2006 6:53am (link) Some Guy: BobGo-- I believe it is correct that there are not only at least two such points, but there are an infintite number of points (in fact, I think that these points must form a continuous path, that crosses the equator at least twice--and so it also crosses any circumference--but I could be wrong about that. In fact, there may be more than one such path, but there is at least one.) The trick to thinking about it is, the points on this path need not all be the same temperature. We're only talking about equivalent temperatures--but any temperature can have an equivalent. We're also assuming that a temperature scale is smooth, so you can slice it up into infinitely fine degrees. This also means that it's not necessarily true for every single temperature on the scale--in other words, it might only be true at any given time for the range between 50F and 51F, for example. It's mathematically true, but in this case the mathematics can reflect the real world. 3.17.2006 2:31pm (link) PT (mail): What's "IVT" ? 3.17.2006 2:57pm (link) John Bouvier (mail): Since this does require continuity of both the temperature and the surface of the earth, wouldn't a discontinuity allow for the conjecture to fail? Continuity of temperature requires a careful definition. It's true that at the sub-molecular level temperature loses it meaning. So we can reasonbly say that the temperature of a point in space is defined as the average for a sphere centered on that point. (Pick any size sphere, as long as it contains enough vibrating molecules to make the concept of temperature meaningful.) But ... In the real world there are truly discontinuities in the surface. The obvious example is an OVERHANG, noted by Dick above. If your great circle passes over an overhang, you truly get a discontinuity in elevation. And therefore you truly get a discontinuity in temperature. Say the overhang is 10 feet high and in the sun. Say you step over the edge to the bottom, which is in the shade. The temperature change may be continuous over this 10-foot drop, but that 10-foot path is not part of the great circle. So does this allow the conjecture to possibly fail?? 3.17.2006 6:00pm (link) Oren (mail): PT - http://en.wikipedia.org/wiki/IVT (jeez, minimum of effort). Alright, here's another good one for you guys to flame over. Prove (minimally!) that given the existence of some wind somewhere, there must be a cyclone somewhere on earth. You may assume that the earth is a perfect sphere with a 2D (flat) atmosphere (ie: wind has no radial component). 3.18.2006 11:55am pageok pageok | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8256565928459167, "perplexity": 816.8753511895064}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131299054.80/warc/CC-MAIN-20150323172139-00118-ip-10-168-14-71.ec2.internal.warc.gz"} |
https://mathoverflow.net/questions/384909/showing-the-positivity-of-the-determinant-of-mathfrakspn-without-making-u | # Showing the positivity of the determinant of $\mathfrak{sp}(n)$ without making use of diagonalization
Let $$\mathfrak{sp}(n)$$ be the lie algebra of compact symplectic group $$\mathrm{SP}(n)$$, regarded as a compact form of $$\mathfrak{sp}(2n,\mathbb{C})$$, so we can talk about its (complex) determinant.
Let $$M\in \mathfrak{sp}(n)$$, then $$M$$ has purely imaginary eigenvalues $$(ix_1,ix_2,\dots,ix_n,-ix_1,-ix_2,\dots,-ix_n)$$, so $$\det(M)=(x_1x_2\cdots x_n)^2\geq 0.$$
My question is
Is there a coordinate independent way to show that every element of $$\mathfrak{sp}(n)$$ has nonnegative determinant?
I would want an argument without using eigenvalues, nor anything that cannot be expressed as a function of the matrix entries.
1. I will like to know if there is some geometric arguments.
I also want to understand the algebra behind. For $$n=2$$, I have tried expanding $$\det(M)$$, but I cannot find a way to express it as a sum of non-negative terms.
A useful way to show the positivity of an algebraic expression is to write it as a sum of terms, and each term is either a norm square, or can be shown to be non-negative by a direct application of the Cauchy-Schwartz inequality. For example, we know $$\mathrm{tr}(A^4)\geq 0$$ because $$\mathrm{tr}(A^4)=||A^2||^2$$.
Of course we have $$\det(M)=(x_1x_2\cdots x_n)^2$$, but the problem $$(x_1x_2\cdots x_n)$$ is not expressible by $$M$$.
1. Can $$\det(M)$$ be expressed a sum of such non-negative terms? If yes, what are they? If not, what are the extra ingredients we need to show the positivity apart from Cauchy Schwartz or completing squares?
• Because some now-deleted answers were confused about this, might be worth recording that the matrices $M \in \mathfrak{sp}(n)$ are those which satisfy $\Omega M = -M^T\Omega$ where $\Omega$ is some fixed non-singular skew-symmetric matrix, e.g. $\Omega = \begin{pmatrix} 0 & I \\ -I & 0 \end{pmatrix}$. Feb 25 at 17:05
Here is a proof of $$\det M\geq 0$$ for $$M\in \mathfrak{sp}(n)$$ based on the lemma that every complex matrix is consimilar to a real matrix.
Acknowledgment: In what follows I was helped by feedback I received at MSE.
By construction, the $$2n\times 2n$$ complex matrix $$M\in \mathfrak{sp}(n)$$ is skew-Hermitian and Hamiltonian, which means that it has the $$n\times n$$ block decomposition $$M=\begin{pmatrix} A&B\\ C&-A^T\end{pmatrix},\;\;\text{with}\;\;A=-A^\ast,\;\;B=B^T=-C^\ast=-\bar{C}.$$ Here $$M^T$$ denotes the transpose, $$\bar{M}$$ the complex conjugate, and $$M^\ast$$ the conjugate transpose.
By continuity of the determinant it is sufficient to consider $$\det A\neq 0$$. Then Schur's determinant identity gives
$$\det M=\det(-AA^T-ACA^{-1}B)=\det(A\bar{A}+A\bar{B}A^{-1}B)$$ $$\qquad=\det(A\bar{A})\det(1+\bar{A}^{-1}\bar{B}A^{-1}B)$$ $$\qquad=|\det A|^2\det(1+\bar{X}X),\;\;\text{with}\;\;X=A^{-1}B.$$
Now I apply the consimilarity lemma, to write $$X=SR\bar{S}^{-1}$$ with $$R$$ a real matrix. This gives $$\det M=|\det A|^2\det(1+\bar{S}R^2\bar{S}^{-1})=|\det A|^2\det(1+R^2)$$ $$\qquad=|\det A|^2\det(1+iR)\det(1-iR)$$ $$\quad=|\det A|^2|\det(1+iR)|^2\geq 0.$$
• Ultimately this seems to use eigenvalues in a way that's pretty similar to what the OP did. Feb 26 at 1:22
• For $X=\begin{pmatrix} a & b \\ c & d \end{pmatrix}$, $|b|^4\det(1+X\overline{X})=||b|^2-\overline{b}^2 \det(X)|^2+|b|^2|a\overline{b}+b\overline{d}|^2$. So it is possible to write the determinant as a sum of norm square in the case $n=2$. Feb 26 at 3:47
• @SamHopkins --- I worked a bit more on the proof, I think I have now removed any reliance on eigenvalues. Feb 26 at 12:43
• @CarloBeenakker Can $R$ be expressed using $X$? I think you proof is using the fact that $X\overline{X}$ is conjugate to the square of a real matrix, which is not so much different from a proof using eigenvalues Feb 27 at 1:05
• a proof along these lines using eigenvalues would rely on the fact that the negative eigenvalues of $X\bar{X}$ have multiplicity two, which is not what I am using here (although indeed this property can be derived from the consimilarity of $X$ with a real matrix). Feb 27 at 7:42 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 34, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9841428995132446, "perplexity": 118.84116489704134}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964362619.23/warc/CC-MAIN-20211203091120-20211203121120-00049.warc.gz"} |
https://community.freefem.org/t/which-mesh-coordinate-is-used-to-compute-dx-du-after-moving-mesh/788 | # Which mesh/coordinate is used to compute dx(du) after moving mesh
Hi,
I am a bit confused with the following dxd(u) – based upon which mesh the derivative is calculated?
Tho=Th;
fespace Vh(Th,P2);
fespace Vho(Tho,P2);
Vh u;
Vho uo;
Tho=Th;
uo=u;
Th=movemesh (Th, …);
dxd(u); //first
u=u; // Is this just an interpolation?
dxd(u); // second
u[ ] = uo[ ]; // is this a Larangian update?
dxd(u); //third
Can I say the first dxd(u) is computed using the old mesh, and the second dxd(u) uses the new mesh, but the derivatives are the same? both of which are different to the third dxd(u)?
Best,
Yongxing.
dx(u) is the derivative of Finite element function u def on mesh Th.
if u is almost == x then du(u) is almost == 1 and this do not depend of the mesh.
The problem is when you say u==x, this is still a Eulerian view, isn’t it? Once you define u=x, for example the density function, on a mesh, then you move (may twist or squeeze) the mesh and let the assiciated u follow the mesh, i.e. a Lagrangian movement, the u cannot be x on the new mesh anymore.
Anyway, can I confirm that in FreeFEM++, u[ ]=uold[ ] is just a Lagrangian update? | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8302003145217896, "perplexity": 2860.1603438764196}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103033925.2/warc/CC-MAIN-20220625004242-20220625034242-00369.warc.gz"} |
https://cstheory.stackexchange.com/questions/12399/is-there-a-name-for-this-property-in-set-valued-analysis-or-combinatorics | # Is there a name for this property in set-valued analysis or combinatorics?
I asked this question a few days ago on MO, but I haven't received an answer. So I thought I would ask here. I have also added a relaxed version of the question here.
Let $F$ be a set-valued, finite-valued map from a set $X$ to subsets of $X$. Consider the following property: $|F(x)| \geq |F(y)|$ for all $x,y$ such that $y \in F(x)$. I have defined this property myself in a specific context but I am not sure what name to give it. I would like to know if there is a standard name for this property or similar property in set-valued analysis, combinatorics or elsewhere. Any suggestions for names would also be appreciated.
As a relaxation, suppose $X$ is given by the disjoint union, $X = \bigcup_{i \in \mathbb{N}} X_i$ and assume that $F$ maps elements of $X_i$ to subsets of $X_{i+1}$ for any $i$. In this case one can think of elements of $X$ as nodes of a tree-like graph, where a parent node $x$ is joined to nodes $y \in F(x)$. There are no edges between nodes belonging to the same partition $X_i$. But a child could have multiple parents, so this graph is not necessarily a tree. The property $F$ here says that every child of a node has at most as many children as the node. Any suggestions for names here would also be helpful.
At first this property appears to be a kind of monotonicity, but I would like to resort to the name "monotone" only if I can't find something more suitable.
• I would consider F as a directed graph instead of a function, but I do not have any suggestion for the name of the property. – Tsuyoshi Ito Aug 25 '12 at 1:31
• Have you looked up the notions of tree-width and clique-width? Not sure if they are exactly what you want, but they may help. – Vijay D Aug 27 '12 at 3:12 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6838065385818481, "perplexity": 114.92270764556692}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-39/segments/1568514573988.33/warc/CC-MAIN-20190920092800-20190920114800-00077.warc.gz"} |
https://www.physicsforums.com/threads/maximum-acceleration-of-a-dot-on-a-slinky.365909/ | # Maximum acceleration of a dot on a slinky?
1. Dec 28, 2009
### uberifrit
A dot (representing vibration) on a slinky exhibits simple harmonic motion as the longitudinal wave passes. The wave has an amplitude of 5,4 * 10^-3 m and a frquency of 4,0 Hz. Find the maximum acceleration of the dot.
Please could you explain what equations to use and how to answer in detail. This would be much appreciated as I am just starting this subject
Last edited: Dec 28, 2009
2. Dec 28, 2009
### pgardn
Since you are studying simple harmonic motion, could you give the equation that describes the position of your dot along a straight line through time? The one that has sine in it?
Similar Discussions: Maximum acceleration of a dot on a slinky? | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9546424150466919, "perplexity": 1005.3781129715967}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891814249.56/warc/CC-MAIN-20180222180516-20180222200516-00065.warc.gz"} |
http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=2006ApJS..166..128Z | other querymodes : Identifierquery Coordinatequery Criteriaquery Referencequery Basicquery Scriptsubmission TAP Outputoptions Help
2006ApJS..166..128Z - Astrophys. J., Suppl. Ser., 166, 128-153 (2006/September-0)
A comprehensive study of 2000 narrow line Seyfert 1 galaxies from the Sloan Digital Sky Survey. I. The sample.
ZHOU H., WANG T., YUAN W., LU H., DONG X., WANG J. and LU Y.
Abstract (from CDS):
This is the first paper in a series dedicated to the study of the emission-line and continuum properties of narrow line Seyfert 1 galaxies (NLS1s). We carried out a systematic search for NLS1s from objects assigned as QSOs'' or galaxies'' in the spectroscopic sample of the Sloan Digital Sky Survey Data Release 3 (SDSS DR3) by a careful modeling of their emission lines and continua. The result is a uniform sample comprising ∼2000 NLS1s. This sample dramatically increases the number of known NLS1s by a factor of ∼10 over previous compilations. This paper presents the parameters of the prominent emission lines and continua, which were measured accurately with typical uncertainties <10%. Taking advantage of such an unprecedented large and uniform sample with accurately measured spectral parameters, we carried out various statistical analyses, some of which were only possible for the first time. The main results found are as follows. (1) Within the overall Seyfert 1 population, the incidence of NLS1s is strongly dependent on the optical, X-ray, and radio luminosities as well as the radio loudness. The fraction of NLS1s peaks around SDSS g-band absolute magnitude Mg~-22 mag in the optical and ∼1043.2 ergs/s in the soft X-ray band, and decreases quickly as the radio loudness increases. (2) On average the relative Fe II emission, R4570=Fe II λλ4434-4684/Hβ, in NLS1s is about twice that in normal active galactic nuclei (AGNs) and is anticorrelated with the broad component width of the Balmer emission lines. (3) The well-known anticorrelation between the width of broad low-ionization lines and the soft X-ray spectral slope for broad line AGNs extends down to FWHM∼1000 km/s in NLS1s, but the trend appears to reverse at still smaller line widths. (4) The equivalent width of Hβ and Fe II emission lines are strongly correlated with the Hβ and continuum luminosities. (5) We do not find any difference between NLS1s and normal AGNs in regard to the narrow line region. (6) We have examined the black hole mass versus stellar velocity dispersion (MBH*) relation for a subsample of 308 NLS1s for which σ*could be measured directly from fitting the starlight in the SDSS spectra with our stellar spectral templates. A significant correlation between MBHand σ*is found, but with the bulk of black hole masses falling below the values expected from the MBH* relation for normal galaxies and normal AGNs. This result indicates that NLS1s are underage AGNs, where the growth of the SMBH lags behind the formation of the galactic bulge. (7) We also find that the FWHM of [N II] line is well correlated with σ*in 206 NLS1s, for which both parameters could be derived with reasonable accuracy. The [N II] width can predict the stellar velocity dispersion to an accuracy of ∼30%. A similar MBH*relation could be found for a larger sample of 613 NLS1s on making use of the more reliable measurements of FWHM[N II].
Journal keyword(s): Galaxies: Active - Galaxies: Seyfert
VizieR on-line data: <Available at CDS (J/ApJS/166/128): table1.dat> | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9223390221595764, "perplexity": 3871.9567167379255}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337595.1/warc/CC-MAIN-20221005073953-20221005103953-00170.warc.gz"} |
https://github.com/qgis/QGIS/commit/519e91e626b2f71177cff3e67c7dfa2375358deb | Skip to content
missing parameter documentation
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@@ -1374,6 +1374,7 @@ this is a rekursive function to get all the child containers :param translationContext: where the objects will be registered :param parent: parent-container containing list of children :param layerId: to store under the correct context .. versionadded:: 3.4 %End
@@ -59,8 +59,8 @@ Sets the ``name`` of the TS file %Docstring Registers the ``string`` to be translated :param translationString: name and path of the object need to be translated :param layerName: the name of the layer :param context: layer name and sub category of object needed to be translated :param source: the name of the object needed to be translated %End void writeTsFile( const QString &locale );
@@ -1304,6 +1304,7 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera * * \param translationContext where the objects will be registered * \param parent parent-container containing list of children * \param layerId to store under the correct context * \since QGIS 3.4 */ void registerTranslatableContainers( QgsTranslationContext *translationContext, QgsAttributeEditorContainer *parent, const QString &layerId );
@@ -74,8 +74,8 @@ class CORE_EXPORT QgsTranslationContext /** * Registers the \a string to be translated * * \param translationString name and path of the object need to be translated * \param layerName the name of the layer * \param context layer name and sub category of object needed to be translated * \param source the name of the object needed to be translated */ void registerTranslation( const QString &context, const QString &source );
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https://calculla.com/fraction_inverse | Fraction inverse (reciprocal) calculator
Calculator finds multiplicative inverse of given fraction or number.
# Fraction, which you're going to invert#
Enter fraction (number)
# Result - fraction inverse step by step#
1 3 4
Step I: Remove whole parts (if exists)
1 · 4 + 3 4
=
7 4
Step II: Invert fraction
4 7
Step III: Convert improper fraction to mixed number (if needed)
4 7
# Some facts#
Remember:
• "Multiplicative inverse" and "reciprocal" is the same thing
• To invert a number X you have to divide 1 by that number. So, multiplicative inverse of X is 1/X.
• To invert fraction you simply need to swap its nominator with denominator. For example inverse of 3/4 is improper fraction 4/3.
• Inverse of number X is Y, when X × Y is equal to one:
$X \times Y = 1$
ⓘ Example: The inverse of number 2 is fraction 1/2 because:
$2 \times \dfrac{1}{2} = 1$
So, whatever number X times inverted X equals one !
• There is no inverse of zero. This also means: any fraction with zero in nominator has no inverse too - no matter what is denominator. Do not be fooled!
• When you invert number lower than one, you get number greater than one and vice versa.
• The inverse of number 1 is 1.
• If you invert some number twice, then you will get the same number. In other words, if you invert the number X and then invert the result again - you get X !
# How to use this tool#
Enter fraction (number), which you want to invert and calculla will present you the step-by-step inversion. To find fraction (number) inverse you need to do below steps:
• I. Remove wholes part. If you want to invert mixed number (or integer number), then you need conver it to improper fraction. For example: 2 1/2 should be converted to 5/2. In other case i.e. when there is no wholes part part, nothing to do in this step. After this step your number will be ready to invert.
• II. Invert fraction i.e. swap its numerator and denominator.
• III. Pull out wholes part. If inverted fraction is improper (numerator greater than denominator) convert it to mixed number.
# Tags and links to this website#
Tags:
Tags to Polish version: | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 2, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8141471743583679, "perplexity": 1971.8275062052082}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593655900335.76/warc/CC-MAIN-20200709131554-20200709161554-00262.warc.gz"} |
https://www.peertechz.com/articles/AOR-4-185.php | ISSN: 2455-1759
##### Archives of Otolaryngology and Rhinology
Surgical Techniques Open Access Peer-Reviewed
# Time of Postoperative Discharge Following Inpatient Tonsillectomy: A Comparison of Two Techniques
### Stephanie M Tominaga1, Rodrigo C Silva2,3, Carolyn Ojano-Dirain4 and William O Collins4*
1University of Florida College of Medicine, USA
2Baylor University Department of Otolaryngology, USA
3Texas Children’s Hospital, USA
4University of Florida College of Medicine, Department of Otolaryngology, USA
*Corresponding author:William O Collins, MD, University of Florida College of Medicine, Department of Otolaryngology, 1345 Center Drive, M2-228, PO Box 100264, Gainesville, FL 32610-0264, USA, Tel: (352) 273-5199; Fax: (352) 392-6781; E-mail: [email protected]
Received: 14 November, 2018 | Accepted: 20 December, 2018 | Published: 21 December, 2018
Cite this as
Tominaga SM, Silva RC, Ojano-Dirain C, Collins WO (2018) Time of Postoperative Discharge Following Inpatient Tonsillectomy: A Comparison of Two Techniques. Arch Otolaryngol Rhinol 4(4): 097-100. DOI: 10.17352/2455-1759.000085
There are many types of surgical instrumentation and techniques used to perform adenotonsillectomy. The choice of instrument depends on several factors and the benefits of clinical outcomes must outweigh the costs of newer technologies. Our study seeks to compare the discharge times following inpatient adenotonsillectomy using monopolar electrosurgery vs. radiofrequency ablation. Participants included thirty children aged 2 to 8 years old who underwent adenotonsillectomy via monopolar electrocautery or radiofrequency ablation and were admitted for inpatient observation. Eighteen patients underwent tonsillectomy with monopolar electrocautery and 10 patients underwent tonsillectomy with radiofrequency ablation. There was no intergroup difference in age, sex, weight, and indication for tonsillectomy. Total hospital length of stay and variance to a goal of discharge before 8 AM on postoperative day #1 was measured. Results demonstrated statistically significant difference in mean length of stay (19.6 vs. 22.4 hours, p = 0.037) and variance to discharge time (139.5 vs. 15.6 min, p = 0.032) in favor of the radiofrequency ablation group. In this small number of patients, there was significantly earlier discharge times in children undergoing adenotonsillectomy with radiofrequency ablation when compared to monopolar electrocautery. Further cost analysis in a larger sample could determine potential cost benefits to the institution.
### Introduction
Adenotonsillectomy is one of the most commonly performed surgical procedures in children worldwide. Epidemiological trends demonstrate a rise in incidence of adenotonsillectomy in recent years as well as a shift for surgical indication from infectious etiologies to sleep-disordered breathing [1,2]. Current clinical practice guidelines recommend overnight monitoring for children with obstructive sleep apnea following tonsillectomy if they are younger than 3 years of age or have severe obstructive sleep apnea [3].
Although various techniques and instruments have evolved to perform standard tonsillectomy, controversy exists over which method provides optimal results. Two commonly used techniques are monopolar electrosurgery (MES) dissection and radiofrequency ablation (RFA). Cost, operating time, blood loss, postoperative hemorrhage, pain, and return to normal activity are factors that must be taken into account when choosing surgical instrumentation.
MES dissection has been a standardized technique for tonsillectomy. Voltage is directly applied across tissue, creating localized heating and damage. The intense heat generated by electrical current causes tissue destruction by fulguration and dessication [4]. The direct heat applied to tissues raises local temperatures to 400 to 600 °C [5].
The RFA device, commercially known as the Coblator (ArthroCare Corporation, Sunnyvale, California), has been used as an alternative surgical tool for tonsillectomy. It operates using radiofrequency which energizes ions in a saline solution. An ionized plasma layer is generated with enough energy to dissociate molecular and chemical bonds. The ablated tissue is cooled by the surrounding saline solution and heat dissipates in the process. This technique allows local temperature of the tissues to remain at 45-85 °C [6].
Because tonsillectomy results in an open wound that heals by second intention, postoperative morbidity is most commonly associated with pain due to the disruption of the mucosa followed by inflammation [7]. RFA requires significantly less heat to ablate tissue when compared to MES, which is theorized to result in decreased postoperative pain. While several studies have reported decreased morbidity with RFA compared to MES dissection tonsillectomy, RFA is a more expensive equipment [5,8-20].
With an increasing emphasis on cost-effective care, the increased equipment cost with the RFA device must be offset by advantages elsewhere. Based on anecdotal patient experience, our hypothesis is that pediatric patients undergoing adenotonsillectomy with RFA were discharged earlier on postoperative day #1 when compared to patients undergoing conventional MES. Shorter hospital stays, even when measured in hours can result in operational advantages for hospitals, including improved patient throughput. The current study aims to measure the time to discharge on postoperative day #1 following adenotonsillectomy performed by MES or RFA, with specific analysis comparing to a goal discharge time of 0800.
### Materials and Methods
This study was a retrospective, non-randomized study enrolling pediatric patients undergoing adenotonsillectomy with planned overnight admission. Surgical technique (MES vs. RFA) and its relation to time to discharge on postoperative day #1 was compared. Protocol was approved by the University of Florida Institutional Review Board (IRB #268-2012). Inclusion criteria included patients 0-18 years of age undergoing elective adenotonsillectomy with a planned overnight admission. Exclusion criteria included patients with significant co-morbidities such as underlying neurological disease, Down syndrome, bleeding disorder, or an inability for the child to communicate pain.
Parents and patients of assenting age were consented and enrolled, and basic demographic data was collected preoperatively. Data included age on the day of surgery, sex, indication for adenotonsillectomy, surgical technique, length of stay (time from surgery completion to discharge), time of discharge, variance of discharge time compared to a goal of 0800, and perioperative complications. Choice of surgical instrument was decided upon by the attending surgeon on the case and was not randomized. All patients underwent standard extracapsular tonsillectomy in order to standardize analysis of the two groups. Postoperative pain management was standardized to weight dependent doses of ibuprofen elixir every 8 hours, and acetaminophen elixir every 4-6 hours as needed. Narcotic analgesics were used sparingly in older patients as needed for breakthrough pain. Decisions on postoperative disposition were made by the attending surgeon and followed previously published clinical practice guidelines [21].
Length of stay (LOS) was calculated in hours, using the time for completion of surgery until the time of discharge from the hospital. Variance to discharge time compared to a goal of 0800 was calculated to show what time patients were discharged from the hospital on postoperative day 1 in reference to 0800 hours. This number could range from negative (i.e. discharge earlier than 0800) or positive (i.e. discharge after 0800). The authors felt that this metric was most important as the goal of improving patient throughput is best achieved with early discharge from the hospital on the morning after surgery. All data, except sex, were analyzed by Student’s t-test (two-tailed) while sex was analyzed by Chi-square using JMPTM Pro 13.0 (SAS Institute Inc., Cary, NC). A statistical value of p<0.05 was considered significant.
### Results
Thirty patients were enrolled in the study; two were subsequently excluded from further analysis because their respective postoperative conditions allowed safe hospital discharge on the same day as surgery. Thus, 28 patients underwent formal data collection and analysis.
The study patients ranged in age from 2 to 8 years of age (mean = 3.3 years). Fourteen patients were female, and the other 14 were male (Table 1). The primary surgical indications included obstructive sleep apnea/sleep disordered breathing (OSA/SDB) in 27 patients, and recurrent pharyngotonsillitis with periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis (PFAPA) syndrome in 1 patient. The increased ratio of OSA or SDB patients reflects the need for postoperative monitoring in these patients, compared with children undergoing tonsillectomy primarily for recurrent tonsillitis.
Eighteen patients underwent MES adenotonsillectomy and 10 patients underwent RFA adenotonsillectomy. The mean age for the MES group was 3.2 years (range 2 to 8 years), and 2.7 years for the RFA group (range 2 to 4 years) (Table 1).
Data on exact time of surgery completion was unavailable in one patient who underwent MES adenotonsillectomy, and thus excluded from final calculation of mean LOS. The mean LOS was calculated based on 17 patients in the MES group, and the entire group of 10 RFA patients.
Mean LOS was 22.4 hours (range, 17.4 to 27.2 hours) for the MES group vs 19.6 hours (range, 17.1 to 23.5 hours) for the RFA group (2-tailed T-test p=0.037). Mean variance to discharge time was 139.5 minutes (range, 34 to 595 minutes) in the MES group compared to 15.6 minutes (range, 75 to 116 minutes) in the RFA group (2-tailed T-test p = 0.032) (Table 1).
One primary postoperative hemorrhage occurred in the RFA group and one clinically significant desaturation was recorded in the MES group. Neither complication resulted in a LOS extending beyond an additional midnight, nor was there any significant long-term sequelae.
### Discussion
There are several surgical instruments currently used to perform extracapsular tonsillectomy. While the majority of studies report that RFA technique is associated with a significant decrease in postoperative pain and faster return to normal activity and diet when compared to conventional MES [5,9-20], some studies report no clinical or statistical difference or benefit [7,22-25]. There is also an inconsistency of results showing benefit of either instrument when assessing intraoperative or postoperative hemorrhage [16,17,23,26]. This discrepancy demands consideration of additional factors that influence the choice of surgical device including ease of use, complication profile, surgeon preference, and cost.
In a hospital-based setting, surgical equipment costs are itemized. Thus, lower equipment costs lead to a more favorable profit margin for the institution. The estimated cost of the RFA hand piece depends on geographic region and individual contracts with vendors, but typically ranges between $180 to 200. In contrast, a typical MES hand piece costs about$15 to 20. In order to justify the increased equipment costs of using RFA over MES, benefit to a hospital’s balance sheet must be demonstrated beyond good clinical outcomes.
Our study shows significantly earlier discharge on postoperative day #1 in patients who underwent RFA tonsillectomy. According to the National (Nationwide) Inpatient Sample (NIS), the largest publicly available inpatient health care database in the United States, the mean daily cost for hospital stay for pediatric patients was $2300 in 2009 [27]. The calculated costs represent the expenses incurred for hospital services such as wages, supplies, and utility. MEC patients spent an average of 2.8 hours longer at the hospital which can be extrapolated to an additional$268.80 in hospital stay cost.
Although difficult to quantify, earlier postoperative discharge may result in other additional benefits. Postoperative patients that occupy a hospital bed longer lead to decreased bed space capacity for additional postoperative patients, emergency department admissions, and ICU-to-floor transfers. The inefficiencies created by longer hospital stays, even when measured in hours, have downstream effects that negatively impact the hospital’s bottom line, as well as patient and family satisfaction.
Limitations of the current study include the small study size and lack of standardization in determining choice of surgical instrument. Although the differences in the meantime of discharge variance were vastly different between the two groups, population size allowed achievement of statistical significance (p=0.032). Further study with greater patient numbers may enhance this finding. Attending surgeon preference was the primary determinant in instrument choice, and factors such as surgical indication, patient age, and level of training of the resident surgeon all factored into the decision. Although efforts were also made to standardize the postoperative pain management protocol, inconsistencies in pain control necessitated the ethical addition of narcotic analgesics in some patients.
Future avenues of study could include expanding the current study to enroll a greater number of patients, randomization of instrument choice, and also quantification of postoperative oral intake as a metric for safe discharge from the hospital. More precise management of postoperative pain according to a predetermined IRB-approved protocol would also help enhance the statistical analysis and validity of future results.
### Conclusion
In this pilot study of pediatric patients undergoing adenotonsillectomy, there were significantly earlier discharge times in children undergoing RFA tonsillectomy as compared to MES tonsillectomy. Further cost analysis in a larger sample would determine potential cost benefits to the institution.
This manuscript was presented as a poster at the spring meeting of the American Society of Pediatric Otolaryngology in Chicago, IL May 2016. The authors also wish to acknowledge the efforts of Kent Mathias, MD and Helen Zhang, MD for their work in data collection
##### Data availability
The data used to support the findings of this study are included within the article.
##### Funding statement
Research and publication of the article is funded by the University of Florida College of Medicine, Department of Otolaryngology.
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© 2018 Tominaga SM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.35629457235336304, "perplexity": 22888.796581616298}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583804001.73/warc/CC-MAIN-20190121172846-20190121194846-00357.warc.gz"} |
https://stats.stackexchange.com/questions/149900/choosing-right-test-to-compare-two-populations | # Choosing right test to compare two populations
I have two populations whose size is 36 and whose values I want to compare.
Example
pop1={-1.6,-1.55,-0.819,-4.86,-5.15,-21,...};
pop2={-3.5,-5.29,-2.11,-6.01,-2.91,-14,...};
I want to understand whether or not the two populations are statistically different and, if so, to know which one has larger values. Here's what I was thinking about doing:
1. I was thinking about simply using a MannWhitney test to compare the medians, but I'm not sure there is something else that I could use.
2. I was also thinking about doing a ranked comparison
Because the two populations' values are somewhat related, I was thinking about attributing an index to each comparison as follows
value index
val1=-1.6,-3.5 1
val2=-1.55,-5.29 1
val3=-0.819,-2.11 1
val4=-4.86,-6.01 1
val5=-5.15,-2.91 2
val6=-21,-14 2
...
The vector v_index would then be compared with another vector v_control only with 1s or 2. I would then determine whether the median of v_index-v_control is statistically different than 0.
What do you guys think?
• Use t-Test for paired two sample for means in the MS Excel tools. – Jskakfdf May 5 '15 at 19:23
• Please tell us what you mean by "statistically different". It's not quite the same thing to compare medians as it is to compare means, for instance, and neither is remotely the same as comparing the underlying distributions. – whuber May 5 '15 at 19:52
• Well, the issue here is that I'm testing the likelyhood of my original vector (with 1 and 2) is to have all 1s, or assessing whether all values in pop1 are larger than pop2. Whether they have similar distributions or not is not very relevant for this case, hence why I was testing whether the medians were different between the original vectors. – Sosi May 5 '15 at 22:45
• Note that without some additional assumption(s), the Wilcoxon-Mann-Whitney is not strictly a comparison of medians (on the other hand, if you make the relevant assumption(s) it as easily becomes a comparison of means) – Glen_b May 6 '15 at 2:19
• The test is actually of the population median of pairwise differences between random values from the two distributions is 0. There are some discussions of it on site. To make that the same as the difference of population means (when it exists) or the difference in medians, one way that's usually quite relevant is to assume the distributions are the same shape apart from a possible location shift. Then not only is it testing that the means or medians are equal under the null, but the two-sample Hodges-Lehmann estimate of the shift also estimates the difference of population means (/medians etc) – Glen_b May 6 '15 at 10:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.637382984161377, "perplexity": 714.5310391669782}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496670255.18/warc/CC-MAIN-20191119195450-20191119223450-00374.warc.gz"} |
https://www.physicsforums.com/threads/simple-rocket-problem.572502/ | # Homework Help: Simple Rocket Problem
1. Jan 30, 2012
### fisselt
I know I've done this problem a few times before but I'm just a fumbling idiot at the moment..
1. The problem statement, all variables and given/known data
Rocket has an acceleration of 12m/s^2 and at an altitude of 1km the motor shuts off. What is the maximum height?
2. Relevant equations
V^2=V_i+2a(x_f-X_i)
x_f=x_i+V_i(t)+1/2at^2
3. The attempt at a solution
V^2=0+2(12)(1000)=154.92m/s
0=154.92t-9.8t^2, t=17.213s
x_f=1000+154.95(17.213)-1/2(9.8)(17.213)^2=2214.82meters
I feel like I'm doing it wrong. 12m/s^2 is the acceleration of the motor, shouldnt their be some force from gravity on the rocket while going towards 1000m?
Thanks for the help.
2. Jan 30, 2012
### PeterO
The acceleration of the motor/rocket combination is the change noticed under the combined influence of the force of gravity, and the thrust force of the rocket motor, and presumably any frictional forces from the air. You are probably supposed to ignore the air resistance - a common approximation used with this sort of problem.
3. Jan 30, 2012
### fisselt
thanks for the help | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8036049008369446, "perplexity": 1343.9867402336515}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376830479.82/warc/CC-MAIN-20181219025453-20181219051453-00331.warc.gz"} |
http://pldml.icm.edu.pl/pldml/element/bwmeta1.element.bwnjournal-article-doi-10_4064-cm105-2-9 | Pełnotekstowe zasoby PLDML oraz innych baz dziedzinowych są już dostępne w nowej Bibliotece Nauki.
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• # Artykuł - szczegóły
## Colloquium Mathematicum
2006 | 105 | 2 | 283-295
## On tame dynamical systems
EN
### Abstrakty
EN
A dynamical version of the Bourgain-Fremlin-Talagrand dichotomy shows that the enveloping semigroup of a dynamical system is either very large and contains a topological copy of β𝓝, or it is a "tame" topological space whose topology is determined by the convergence of sequences. In the latter case we say that the dynamical system is tame. We show that (i) a metric distal minimal system is tame iff it is equicontinuous, (ii) for an abelian acting group a tame metric minimal system is PI (hence a weakly mixing minimal system is never tame), and (iii) a tame minimal cascade has zero topological entropy. We also show that for minimal distal-but-not-equicontinuous systems the canonical map from the enveloping operator semigroup onto the Ellis semigroup is never an isomorphism. This answers a long standing open question. We give a complete characterization of minimal systems whose enveloping semigroup is metrizable. In particular it follows that for an abelian acting group such a system is equicontinuous.
283-295
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2006
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autor
• Department of Mathematics, Tel Aviv University, Tel Aviv, Israel | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9455052018165588, "perplexity": 1421.5963623298476}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662619221.81/warc/CC-MAIN-20220526162749-20220526192749-00673.warc.gz"} |
https://forum.allaboutcircuits.com/threads/calculate-moment-of-inertia-j-and-magnetic-field-b-of-a-permanent-magnet-dc-motor-pmdc-motor.167898/ | # Calculate Moment of Inertia(J) and Magnetic Field B of a permanent magnet DC motor (PMDC) motor
#### charlie_89
Joined Mar 13, 2020
4
hello,
can anyone tell me how to find the moment of inertia(J) and magnetic field(B) value of a PMDC motor? I am currently working on closed loop DC motor control for my control systems project. And I am supposed to find the constants( i.e, J, B, L, R and other parameters.)
Below, I attach motor design and other specification details for your reference.
Thankyou.
#### Attachments
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#### MrAl
Joined Jun 17, 2014
8,249
Hello,
Do you have an example using the data you have provided?
I ask because usually to calculate J you have to have detailed mechanical drawings and specifications or you have to be able to do detailed tests on the actual motor itself.
#### drc_567
Joined Dec 29, 2008
1,110
A possib!e method to obtain an estimate for the moment of inertia would be to first measure the locked rotor torque. This measurement is obtained using the rated motor amps and sufficient weight placed radially on the motor shaft ... A small pulley may be utilized. The second step is to measure the no-load, or free running speed of the motor at the rated amps. Plot the two points and draw a straight line. Using the formula:
$$T=Jdω/dt$$
Find an estimate for the moment of inertia J.
edit: The stall torque is given in the data sheet. Measure the no-load speed. Plot the two points and draw a line. Maybe the calculated number will be approximately correct. See if the motor manufacturer will provide a value.
Last edited:
#### charlie_89
Joined Mar 13, 2020
4
A possib!e method to obtain an estimate for the moment of inertia would be to first measure the locked rotor torque. This measurement is obtained using the rated motor amps and sufficient weight placed radially on the motor shaft ... A small pulley may be utilized. The second step is to measure the no-load, or free running speed of the motor at the rated amps. Plot the two points and draw a straight line. Using the formula:
$$T=Jdω/dt$$
Find an estimate for J, the moment of inertia J.
edit: The stall torque is given in the data sheet. Measure the no-load speed. Plot the two points and draw a line. Maybe the calculated number will be approximately correct. See if the motor manufacturer will provide a value.
#### charlie_89
Joined Mar 13, 2020
4
Thank you! Will follow the procedure which you mentioned to calculate and will get back to you.
#### drc_567
Joined Dec 29, 2008
1,110
... Still trying to close in on a practical solution.
It seems that in an approximate sense, the slope of the line as plotted above should be:
$$m=ΔT/Δω$$
The question then is m equal to J?
This implies that
$$ΔT=JΔω$$
If this is reasonably correct, then appropriate numbers, over a small interval, could be obtained from the plotted line.
Last edited:
#### cake4all
Joined Oct 19, 2018
8
Sorry if I am a bit too late. But maybe somebody else will still profit from this post.
In general, you need a (differential equation) model in order to perform process identification. For a simple dc motor, often the following model is used:
$$L_A \cdot \dfrac{d i_A(t)}{dt} = - R_A \cdot i_A(t) - U_{ind} + U_{A}(t)$$
$$J \cdot \dfrac{d \omega}{dt} = c_A \cdot \phi_E \cdot i_A(t) - m_L$$
(From the german wikipedia.)
$$m_L$$ is the load torque, $$c_A \cdot \phi_E$$ is for most dc motors roughly a constant. $$R_A$$ is the resistance of the armature, and $$L_A$$ is its inductance. Approximately $$U_{ind} = c_A \cdot \phi_E \cdot \omega$$ holds. $$i_A(t)$$ is the current through the armature and $$U_A(t)$$ is its voltage (this is in most cases the system input).
There are also more complicated models (mostly nonlinear), that include much more behaviour (e.g. different types of friction). See here for an example.
As soon as you have a differential equation model, you can use system identification methods for finding the parameters. I am too lazy to write about its aspects. Just a grab a suitable textbook about control theory/system identification or just use the very popular matlab system identification toolbox.
Summarized, you need to perform the following steps:
1. Find a suitable differential equation model.
2. Find a suitable system identification method.
3. Perform experiments and capture the data.
4. Apply system identification methods to your data.
Kind Regards | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7689658403396606, "perplexity": 1242.1578507556028}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-25/segments/1623487635920.39/warc/CC-MAIN-20210618073932-20210618103932-00232.warc.gz"} |
https://www.quantamagazine.org/mathematician-solves-computer-science-conjecture-in-two-pages-20190725/?fbclid=IwAR3tS-yhN7TwnGgcRpF5RYgfHD3nEC9CUobmXyj278qSkRtGe7kMTxKLxQE | # Decades-Old Computer Science Conjecture Solved in Two Pages
The “sensitivity” conjecture stumped many top computer scientists, yet the new proof is so simple that one researcher summed it up in a single tweet.
A paper posted online this month has settled a nearly 30-year-old conjecture about the structure of the fundamental building blocks of computer circuits. This “sensitivity” conjecture has stumped many of the most prominent computer scientists over the years, yet the new proof is so simple that one researcher summed it up in a single tweet.
“This conjecture has stood as one of the most frustrating and embarrassing open problems in all of combinatorics and theoretical computer science,” wrote Scott Aaronson of the University of Texas, Austin, in a blog post. “The list of people who tried to solve it and failed is like a who’s who of discrete math and theoretical computer science,” he added in an email.
The conjecture concerns Boolean functions, rules for transforming a string of input bits (0s and 1s) into a single output bit. One such rule is to output a 1 provided any of the input bits is 1, and a 0 otherwise; another rule is to output a 0 if the string has an even number of 1s, and a 1 otherwise. Every computer circuit is some combination of Boolean functions, making them “the bricks and mortar of whatever you’re doing in computer science,” said Rocco Servedio of Columbia University.
Over the years, computer scientists have developed many ways to measure the complexity of a given Boolean function. Each measure captures a different aspect of how the information in the input string determines the output bit. For instance, the “sensitivity” of a Boolean function tracks, roughly speaking, the likelihood that flipping a single input bit will alter the output bit. And “query complexity” calculates how many input bits you have to ask about before you can be sure of the output.
Each measure provides a unique window into the structure of the Boolean function. Yet computer scientists have found that nearly all these measures fit into a unified framework, so that the value of any one of them is a rough gauge for the value of the others. Only one complexity measure didn’t seem to fit in: sensitivity.
In 1992, Noam Nisan of the Hebrew University of Jerusalem and Mario Szegedy, now of Rutgers University, conjectured that sensitivity does indeed fit into this framework. But no one could prove it. “This, I would say, probably was the outstanding open question in the study of Boolean functions,” Servedio said.
“People wrote long, complicated papers trying to make the tiniest progress,” said Ryan O’Donnell of Carnegie Mellon University.
Now Hao Huang, a mathematician at Emory University, has proved the sensitivity conjecture with an ingenious but elementary two-page argument about the combinatorics of points on cubes. “It is just beautiful, like a precious pearl,” wrote Claire Mathieu, of the French National Center for Scientific Research, during a Skype interview.
Aaronson and O’Donnell both called Huang’s paper the “book” proof of the sensitivity conjecture, referring to Paul Erdős’ notion of a celestial book in which God writes the perfect proof of every theorem. “I find it hard to imagine that even God knows how to prove the Sensitivity Conjecture in any simpler way than this,” Aaronson wrote.
## A Sensitive Matter
Imagine, Mathieu said, that you are filling out a series of yes/no questions on a bank loan application. When you’re done, the banker will score your results and tell you whether you qualify for a loan. This process is a Boolean function: Your answers are the input bits, and the banker’s decision is the output bit.
If your application gets denied, you might wonder whether you could have changed the outcome by lying on a single question — perhaps, by claiming that you earn more than $50,000 when you really don’t. If that lie would have flipped the outcome, computer scientists say that the Boolean function is “sensitive” to the value of that particular bit. If, say, there are seven different lies you could have told that would have each separately flipped the outcome, then for your loan profile, the sensitivity of the Boolean function is seven. Computer scientists define the overall sensitivity of the Boolean function as the biggest sensitivity value when looking at all the different possible loan profiles. In some sense, this measure calculates how many of the questions are truly important in the most borderline cases — the applications that could most easily have swung the other way if they’d been ever so slightly different. Sensitivity is usually one of the easiest complexity measures to compute, but it’s far from the only illuminating measure. For instance, instead of handing you a paper application, the banker could have interviewed you, starting with a single question and then using your answer to determine what question to ask next. The largest number of questions the banker would ever need to ask before reaching a decision is the Boolean function’s query complexity. This measure arises in a host of settings — for instance, a doctor might want to send a patient for as few tests as possible before reaching a diagnosis, or a machine learning expert might want an algorithm to examine as few features of an object as possible before classifying it. “In a lot of situations — diagnostic situations or learning situations — you’re really happy if the underlying rule … has low query complexity,” O’Donnell said. Other measures involve looking for the simplest way to write the Boolean function as a mathematical expression, or calculating how many answers the banker would have to show a boss to prove they had made the right loan decision. There’s even a quantum physics version of query complexity in which the banker can ask a “superposition” of several questions at the same time. Figuring out how this measure relates to other complexity measures has helped researchers understand the limitations of quantum algorithms. With the single exception of sensitivity, computer scientists proved that all these measures are closely linked. Specifically, they have a polynomial relationship to each other — for example, one measure might be roughly the square or cube or square root of another. Only sensitivity stubbornly refused to fit into this neat characterization. Many researchers suspected that it did indeed belong, but they couldn’t prove that there were no strange Boolean functions out there whose sensitivity had an exponential rather than polynomial relationship to the other measures, which in this setting would mean that the sensitivity measure is vastly smaller than the other measures. “This question was a thorn in people’s sides for 30 years,” Aaronson said. ## Cornering the Solution Huang heard about the sensitivity conjecture in late 2012, over lunch with the mathematician Michael Saks at the Institute for Advanced Study, where Huang was a postdoctoral fellow. He was immediately taken with the conjecture’s simplicity and elegance. “Starting from that moment, I became really obsessed with thinking about it,” he said. Huang added the sensitivity conjecture to a “secret list” of problems he was interested in, and whenever he learned about a new mathematical tool, he considered whether it might help. “Every time after I’d publish a new paper, I would always go back to this problem,” he said. “Of course, I would give up after a certain amount of time and work on some more realistic problem.” Huang knew, as did the broader research community, that the sensitivity conjecture could be settled if mathematicians could prove an easily stated conjecture about collections of points on cubes of different dimensions. There’s a natural way to go from a string of n 0s and 1s to a point on an n-dimensional cube: Simply use the n bits as the coordinates of the point. For instance, the four two-bit strings — 00, 01, 10 and 11 — correspond to the four corners of a square in the two-dimensional plane: (0,0), (0,1), (1,0) and (1,1). Likewise, the eight three-bit strings correspond to the eight corners of a three-dimensional cube, and so on in higher dimensions. A Boolean function, in turn, can be thought of as a rule for coloring these corners with two different colors (say, red for 0 and blue for 1). In 1992, Craig Gotsman, now of the New Jersey Institute of Technology, and Nati Linial of Hebrew University figured out that proving the sensitivity conjecture can be reduced to answering a simple question about cubes of different dimensions: If you choose any collection of more than half the corners of a cube and color them red, is there always some red point that is connected to many other red points? (Here, by “connected,” we mean that the two points share one of the outer edges of the cube, as opposed to being across a diagonal.) If your collection contains exactly half the corners of the cube, it’s possible that none of them will be connected. For example, among the eight corners of the three-dimensional cube, the four points (0,0,0), (1,1,0), (1,0,1) and (0,1,1) all sit across diagonals from one another. But as soon as more than half the points in a cube of any dimension are colored red, some connections between red points must pop up. The question is: How are these connections distributed? Will there be at least one highly connected point? In 2013, Huang started thinking that the best route to understanding this question might be through the standard method of representing a network with a matrix that tracks which points are connected and then examining a set of numbers called the matrix’s eigenvalues. For five years he kept revisiting this idea, without success. “But at least thinking about it [helped] me quickly fall asleep many nights,” he commented on Aaronson’s blog post. Then in 2018, it occurred to Huang to use a 200-year-old piece of mathematics called the Cauchy interlace theorem, which relates a matrix’s eigenvalues to those of a submatrix, making it potentially the perfect tool to study the relationship between a cube and a subset of its corners. Huang decided to request a grant from the National Science Foundation to explore this idea further. Then last month, as he sat in a Madrid hotel writing his grant proposal, he suddenly realized that he could push this approach all the way to fruition simply by switching the signs of some of the numbers in his matrix. In this way, he was able to prove that in any collection of more than half the points in an n-dimensional cube, there will be some point that is connected to at least$latex \sqrt{n}\$ of the other points — and the sensitivity conjecture instantly followed from this result.
When Huang’s paper landed in Mathieu’s inbox, her first reaction was “uh-oh,” she said. “When a problem has been around 30 years and everybody has heard about it, probably the proof is either very long and tedious and complicated, or it’s very deep.” She opened the paper expecting to understand nothing.
But the proof was simple enough for Mathieu and many other researchers to digest in one sitting. “I expect that this fall it will be taught — in a single lecture — in every master’s-level combinatorics course,” she messaged over Skype.
Huang’s result is even stronger than necessary to prove the sensitivity conjecture, and this power should yield new insights about complexity measures. “It adds to our toolkit for maybe trying to answer other questions in the analysis of Boolean functions,” Servedio said.
Most importantly, though, Huang’s result lays to rest nagging worries about whether sensitivity might be some strange outlier in the world of complexity measures, Servedio said. “I think a lot of people slept easier that night, after hearing about this.” | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.45901569724082947, "perplexity": 1114.7536570644916}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540569332.20/warc/CC-MAIN-20191213230200-20191214014200-00148.warc.gz"} |
https://www.stata.com/features/generalized-estimating-equations/ | » Home » Products » Features » Panel data » Generalized estimating equations
## Generalized estimating equations: xtgee
The use of panel-data models has exploded in the past ten years as analysts more often need to analyze richer data structures. Some examples of panel data are nested datasets that contain observations of smaller units nested within larger units. An example might be counties (the replication) in various states (the panel identifier). Other examples of panel data are longitudinal, having multiple observations (the replication) on the same experimental unit (the panel identifier) over time. xtgee allows either type of panel data.
Stata estimates extensions to generalized linear models in which you can model the structure of the within-panel correlation. This extension allows users to fit GLM-type models to panel data.
xtgee offers a rich collection of models for analysts. These models correspond to population-averaged (or marginal) models in the panel-data literature.
What makes xtgee useful is the number of statistical models that it generalizes for use with panel data, the richer correlation structure with models available in other commands, and the availability of robust standard errors, which do not always exist in the equivalent command.
In this example, we consider a probit model in which we wish to model whether a worker belongs to the union based on the person's age and whether they are living outside of an SMSA. The people in the study appear multiple times in the dataset (this type of panel dataset is commonly referred to as a longitudinal dataset), and we assume that the observations on a given person are more correlated than those between different persons.
. webuse nlswork
(National Longitudinal Survey. Young Women 14-26 years of age in 1968)
. xtset idcode
panel variable: idcode (unbalanced)
. xtgee union age not_smsa, family(binomial) link(probit) corr(exchangeable)
Iteration 1: tolerance = .05859927
Iteration 2: tolerance = .00346479
Iteration 3: tolerance = .0001277
Iteration 4: tolerance = 4.486e-06
Iteration 5: tolerance = 1.548e-07
GEE population-averaged model Number of obs = 19,226
Group variable: idcode Number of groups = 4,150
Family: binomial min = 1
Correlation: exchangeable avg = 4.6
max = 12
Wald chi2(2) = 30.23
Scale parameter: 1 Prob > chi2 = 0.0000
union Coef. Std. Err. z P>|z| [95% Conf. Interval]
age .0045624 .0013959 3.27 0.001 .0018264 .0072984
not_smsa -.1440246 .0318838 -4.52 0.000 -.2065156 -.0815336
_cons -.8770284 .0479603 -18.29 0.000 -.9710288 -.7830279
### xtgee options
xtgee allows these options:
Families Bernoulli/binomial gamma Gaussian inverse Gaussian negative binomial Poisson Links cloglog identity log logit negative binomial odds power power probit reciprocal Correlation structures independent exchangeable autoregressive stationary nonstationary unstructured user-specified
Assume an independent correlation structure that ignores the panel structure of the data. Under this assumption, xtgee will produce answers already provided by Stata’s nonpanel estimation commands. Examples of situations when xtgee provides the same answers are given in the table shown below.
Family Link Correlation Equivalent Stata gaussian identity independent regress gaussian identity exchangeable xtreg, re gaussian identity exchangeable xtreg, pa binomial cloglog independent cloglog (see note 1) binomial cloglog exchangeable xtcloglog, pa binomial logit independent logit or logistic binomial logit exchangeable xtlogit, pa binomial probit independent probit (see note 2) binomial probit exchangeable xtprobit, pa nbinomial nbinomial independent nbreg (see note 3) poisson log independent poisson poisson log exchangeable xtpoisson, pa gamma log independent streg, dist(exp) nohr (see note 4) family link independent glm, irls (see note 5)
Note 1 For cloglog estimation, xtgee with corr(independent) and cloglog will produce the same coefficients, but the standard errors will be only asymptotically equivalent because cloglog is not the canonical link for the binomial family. Note 2 For probit estimation, xtgee with corr(independent) and probit will produce the same coefficients, but the standard errors will be only asymptotically equivalent because probit is not the canonical link for the binomial family. If the binomial denominator is not 1, the equivalent maximum-likelihood command is bprobit. Note 3 Fitting a negative binomial model using xtgee (or glm) will yield results conditional on the specified value of alpha. nbreg, however, estimates that parameter and provides unconditional estimates. Note 4 xtgee with corr(independent) can be used to fit exponential regressions, but this requires specifying scale(1). As with probit, the xtgee-reported standard errors will be only asymptotically equivalent to those produced by streg, dist(exp) nohr because log is not the canonical link for the gamma family. xtgee cannot be used to fit exponential regressions on censored data. Using the independent correlation structure, xtgee will fit the same model as the glm, irls command if the family–link combination is the same. Note 5 If xtgee is equivalent to another command, using corr(independent) and the vce(robust) option with xtgee corresponds to using vce(cluster clustvar) option in the equivalent command, where clustvar corresponds to the panel variable.
If you choose to model the intracluster correlation as an identity matrix (by specifying the name of an existing identity matrix in the option corr), GEE estimation reduces to a generalized linear model, and the results will be identical to estimation by glm.
. glm union age not_smsa, family(gauss) link(identity)
Iteration 0: log likelihood = -10713.086
Generalized linear models No. of obs = 19,226
Optimization : ML Residual df = 19,223
Scale parameter = .1784791
Deviance = 3430.904127 (1/df) Deviance = .1784791
Pearson = 3430.904127 (1/df) Pearson = .1784791
Variance function: V(u) = 1 [Gaussian]
Link function : g(u) = u [Identity]
AIC = 1.114749
Log likelihood = -10713.08631 BIC = -186185.1
OIM
union Coef. Std. Err. z P>|z| [95% Conf. Interval]
age .0018369 .0004926 3.73 0.000 .0008714 .0028024
not_smsa -.0648492 .0067672 -9.58 0.000 -.0781126 -.0515858
_cons .1950571 .0158061 12.34 0.000 .1640777 .2260365
. xtgee union age not_smsa, family(gauss) link(identity) corr(indep)
Iteration 1: tolerance = 6.777e-16
GEE population-averaged model Number of obs = 19,226
Group variable: idcode Number of groups = 4,150
Family: Gaussian min = 1
Correlation: independent avg = 4.6
max = 12
Wald chi2(2) = 103.63
Scale parameter: .1784513 Prob > chi2 = 0.0000
Pearson chi2(19226): 3430.90 Deviance = 3430.90
Dispersion (Pearson): .1784513 Dispersion = .1784513
union Coef. Std. Err. z P>|z| [95% Conf. Interval]
age .0018369 .0004926 3.73 0.000 .0008715 .0028023
not_smsa -.0648492 .0067666 -9.58 0.000 -.0781116 -.0515869
_cons .1950571 .0158049 12.34 0.000 .1640801 .2260341
We could fill up lots of space demonstrating other ways that xtgee is equivalent to other features of Stata, but the real power is in using it for its intended use and modeling the correlation that exists in the panels. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7122139930725098, "perplexity": 10653.977207848151}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-30/segments/1563195528013.81/warc/CC-MAIN-20190722113215-20190722135215-00031.warc.gz"} |
https://iccl.inf.tu-dresden.de/web/LATPub588/en | # The Fuzzy Description Logic G-FL_0 with Greatest Fixed-Point Semantics
##### Stefan BorgwardtStefan Borgwardt, José A. Leyva GalanoJosé A. Leyva Galano, Rafael PeñalozaRafael Peñaloza
Stefan Borgwardt, José A. Leyva Galano, Rafael Peñaloza
The Fuzzy Description Logic G-FL_0 with Greatest Fixed-Point Semantics
In Eduardo Fermé and João Leite, eds., Proceedings of the 14th European Conference on Logics in Artificial Intelligence (JELIA'14), volume 8761 of Lecture Notes in Artificial Intelligence, 62-76, 2014. Springer
• KurzfassungAbstract
We study the fuzzy extension of the Description Logic FL_0 with semantics based on the Gödel t-norm. We show that subsumption w.r.t. a finite set of primitive definitions, using greatest fixed-point semantics, can be characterized by a relation on weighted automata. We use this result to provide tight complexity bounds for reasoning in this logic, showing that it is PSpace-complete. If the definitions do not contain cycles, subsumption becomes co-NP-complete.
• Forschungsgruppe:Research Group: Automatentheorie
The final publication is available at Springer.
@inproceedings{ BoLP-JELIA14,
title = {The Fuzzy Description Logic {\textsf{G}-$\mathcal{FL}_0$} with Greatest Fixed-Point Semantics}, | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9481954574584961, "perplexity": 5714.597011016258}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439738351.71/warc/CC-MAIN-20200808194923-20200808224923-00097.warc.gz"} |
https://math.stackexchange.com/questions/1802813/prove-upper-bound-for-recurrence | # Prove upper bound for recurrence
I am working on problem set 8 problem 3 from MIT's Fall 2010 OCW class 6.042J. This is covered in chapter 10 which is about recurrences.
Here is the problem:
$$A_0 = 2$$ $$A_{n+1} = A_n/2 + 1/A_n, \forall n \ge 1$$
Prove
$$A_n \le \sqrt2 + 1/2^n, \forall n \ge 0$$
I have graphed the recurrence and the upper bound and they seem to both converge on $\sqrt2$.
Also, if you ignore the boundary condition $A_0 = 2$ then you find that $\sqrt2$ is a solution to the main part of the recurrence. i.e. $\sqrt2 = \sqrt2/2 + 1/\sqrt2$.
The chapter and videos on recurrences have a lot to say about a kind of cookbook solution to divide and conquer recurrences which they call the Akra-Bazzi Theorem. But this recurrence does not seem to be in the right form for that theorem. If it were in the form $A_{n+1} = A_n/2 + g(n)$ then the theorem would give you an asymptotic bound. But $1/A_n$ is not a simple function of $n$ like a polynomial. Instead it is part of the recurrence.
Also, the chapter has a variety of things to say about how to guess the right solution and plug it into an inductive proof, but I haven't had much success. I have tried possible solutions of various forms like $a_n = \sqrt2+a/b^n$ and tried solving for the constants $a$ and $b$ but to no avail.
So, if someone can point me in the right direction that would be great. I always assume that the problem sets are based on something taught in the videos and in the text of the book but I am having trouble tracking this one down.
Bobby
We show by induction that $$\sqrt{2}\lt A_n\le \sqrt{2}+\frac{1}{2^n}.\tag{1}$$ Suppose the result holds at $n=k$. We show the result holds at $n=k+1$.
For the inequality on the right of (1), we need to show that $$\frac{A_k}{2}+\frac{1}{A_k}\le \sqrt{2}+\frac{1}{2^{k+1}}.$$ By the induction hypothesis, we have $$\frac{A_k}{2}+\frac{1}{A_k}\le \frac{\sqrt{2}}{2}+\frac{1}{2^{k+1}}+\frac{1}{\sqrt{2}}=\sqrt{2}+\frac{1}{2^{k+1}},$$ which takes care of the induction step for the inequality on the right of (1).
We still need to show that $\sqrt{2}\lt A_{k+1}$. Let $A_k=\sqrt{2}+\epsilon$, where $\epsilon$ is positive. Then $$A_{k+1}=\frac{\sqrt{2}+\epsilon}{2}+\frac{1}{\sqrt{2}+\epsilon}=\frac{4+2\sqrt{2}\epsilon+\epsilon^2}{2(\sqrt{2}+\epsilon)}\gt \frac{4+2\sqrt{2}\epsilon}{2(\sqrt{2}+\epsilon)}=\sqrt{2}.$$ This completes the induction step for the inequality on the left of (1).
Remark: The inequality (1) and squeezing show that $A_n$ indeed has limit $\sqrt{2}$.
• It didn't occur to me to prove that $A_n \ge \sqrt2$ and then substitute $\sqrt2$ in the $1/A_n$ term. Much easier that way. Thanks. – Bobby Durrett May 28 '16 at 2:36
• @BobbyDurrett: You are welcome. The inequality $A_n\gt \sqrt{2}$ is not mentioned explicitly in what you are asked to show, but when one tries to push the induction through, it becomes clear that it is necessary for the proof. – André Nicolas May 28 '16 at 2:40
• Nice induction for the $>\sqrt{2}$ part. I didn't manage it immediately, that's why I showed it studying the map $x\mapsto \frac{x}2+\frac{1}{x}$. – Daniel Robert-Nicoud May 28 '16 at 11:09
Let $$B_k = \frac{A_k}{\sqrt{2}}$$ Then $B_0 = \sqrt{2}$ and $$B_{n+1} = \frac12\left(B_n+\frac{1}{B_n} \right)$$ Thus $b_n$ is the $n$-th guess if you perform Newton's algorithm to try to find $\sqrt{1}$ starting with a guess of $\sqrt{2}$.
This recursion can be solved in closed form using the formula for the hyperbolic tangent of $2x$ in terms of $\tanh x$: $$\tanh(2x) = \frac{2 \tanh x}{1+\tanh^2{x}}$$ . The result looks something like $$B_n = \tanh\left( 2^n \theta\right)$$ where $\theta = \tanh^{-1} B_0$; the answer I have given is off in that every other term needs to be the reciprocal of what I wrote, but the general idea will work.
Once you have that, you can know exactly what $B_n$ is and prove the relation; or better yet, use the error analysis for Newton's method to get an estimate of how close to 1 you would be.
We want to apply induction, but we need also a lower bound on $A_n$ for the $\frac{1}{n}$ term. We can show that $A_n\ge\sqrt{2}$ as follows:
Let $f(x) = \frac{x}{2} + \frac{1}{x}$. Then $f'(x) = \frac{1}{2} - \frac{1}{x^2}$ which has a zero at $x = \sqrt{2}$ where $f(\sqrt{2}) = \sqrt{2}$, and is positive for $x>\sqrt{2}$. This shows that $f(x)\ge\sqrt{2}$ whenever $x\ge\sqrt{2}$, and as $A_{n+1} = f(A_n)$, we have that $A_n\ge\sqrt{2}$ for all $n\ge0$.
Then to conclude:
The case $n=0$ is trivially true.
For $n\ge0$ we have that $$A_{n+1} = \frac{A_n}{2} + \frac{1}{A_n}.$$ By induction hypothesis and what we have shown above, this has as upper bound $$A_{n+1}\le \frac{\sqrt{2} + 2^{-n-1}}{2} + \frac{1}{\sqrt{2}} = \sqrt{2} + 2^{-n-1}.$$
Three steps: Use the definition of $A_n$ and algebra to establish that $$A_{n+1}-\sqrt 2 = {(A_n-\sqrt 2)^2\over 2A_n}.\tag1$$ Next, use (1) to prove by induction that $$A_n\ge\sqrt 2\ \text{for every n.}\tag2$$ Finally, use (1) and (2) to prove by induction that $$A_n-\sqrt2 \le \frac1{2^{n}}\ \text{for every n.}\tag2$$
Your sequence is $$A_{n+1} = \frac{1}{2} A_n + \frac{1}{A_n}$$ where the last term features a division which reminds of the Newton-Raphson iteration.
Newton Raphson iteration takes the root of the tangent as next step for estimating a root of $f$: $$0 = T'(x_{n+1}) = f(x_n) + f'(x_n) (x_{n+1} - x_n) \iff \\ x_{n+1} = x_n - \frac{f(x_n)}{f'(x_n)}$$ by comparison we have $$-\frac{1}{2}A_n + \frac{1}{A_n} = - \frac{A_n^2-2}{2A_n} = - \frac{f(A_n)}{f'(A_n)}$$ and see $f(x) = x^2 - 2$, the function used to iterate against the root $\sqrt{2}$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9608221650123596, "perplexity": 119.9180937019314}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560628000367.74/warc/CC-MAIN-20190626154459-20190626180459-00518.warc.gz"} |
https://www.physicsforums.com/threads/area-under-the-curve-problem-but-theres-a-twist.41402/ | # Area under the curve problem, but there's a twist
1. Sep 1, 2004
### relativitydude
I have a unique area under a curve problem. Say we have a function y = x^2. Ok, so, the area under that curve is just the integral of x^2 from 0 to some value of x. That's easy. Lets call this area A.
Now normally if we wanted to find the area under a height, we would simply mulitply height by the value of x and subtract the integrated form to find the are above the curve to that height. Lets call this area B.
I cant use this method. I cant simply say h*x minus the integral of whatever to find area B. Is there another way to find area B while knowing the function but not involving area A in any way?
2. Sep 1, 2004
### mathwonk
try making this confusing question a little more precise. an example could help.
3. Sep 1, 2004
### relativitydude
I included a diagram. I need to find area A and area B separately. I cant find area B by subtracting A out of it and conversely I cant find area A by subtracting B out of it.
File size:
5.5 KB
Views:
118
4. Sep 1, 2004
### Hurkyl
Staff Emeritus
Why can't you?
5. Sep 1, 2004
I just cant.
6. Sep 1, 2004
### Ethereal
Why not? Try it for some value of x and h. What's the problem? On the other hand, maybe you could try expressing the f(x) in terms of y and integrating wrt y instead to find B directly.
PS. What did you use to create the picture? It looks rather neat.
7. Sep 1, 2004
### relativitydude
I cant do it the normal way because my problem that this assists boils down to 1=1, a true yet uninspiring finding. I will try it with your suggestions, Ethereal.
That chart? Eh, that's nothing. I made it in Adobe Illustrator. You can draw ANYTHING in that program.
8. Sep 1, 2004
### Hurkyl
Staff Emeritus
If you found one of them via the integral, couldn't you find the other by subtracting?
9. Sep 1, 2004
### relativitydude
I said I cant use the subtraction method.
10. Sep 2, 2004
### Galileo
Do you mean you don't know how? Or aren't you allowed to use it for solving the problem?
If you're looking for another way to find area B, here's a hint:
11. Sep 2, 2004
### relativitydude
I am not allowed.
Thanks Gilleo, will do.
12. Sep 2, 2004
### JonF
wouldn't the inverse function of x^2 have the same area if you integrated along the x-axis and used the height as the upper bound limit?
13. Sep 3, 2004
### SpatialVacancy
Here's how
Find $f^{-1}(x)$. In this case, you are using $f(x) = x^2 [/tex]. The inverse of this function is [itex] f(x) = \sqrt{x}$. You can now integrate, but make sure to adjust your limits of integration. If you wanted from 0 to 3 of the original function, that would translate to 0 to 9 of the inverse. Just plug in the original limits to the inverse (y) to obtain your new limits.
Hope this helps!
14. Sep 3, 2004
### Galileo
I don't know if inversion will help. Inversion mirrors the function in (through?) the line y=x.
My idea was to mirror the function in the x-axis, then add the height h to the function and then integrate. (or alternatively subtract the height from the function and then mirror it).
But the calculation would be exactly the same if you were calculating the area of the rectangle and subtract area A. So it seems silly not to use this method and do use the above method.
Subtract height: f(x)-h
Mirror: h-f(x)
Integrate: $h\Delta x - \int f(x)dx$
It's the same :)
Last edited: Sep 3, 2004
15. Sep 3, 2004
### JonF
Well basically it is the same exact thing as what you planed on doing. The area between the function and the y-axis is the same as its inverse function and the x-axis.
16. Sep 8, 2004
### Hessam
ok i'm not sure if anyone mentioned htis but....
lets say the equation was y = x^2.... you wanted to find area B
could you not find the integral from 0 -> x by changing the equation ... by flipping it upside down (reflect upon x-axis) and shift it up h units?
thus you get
y = -x^2 + h
and find integral from 0-->x now?
correct me if i'm wrong | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8810521960258484, "perplexity": 1208.3940466733015}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698543316.16/warc/CC-MAIN-20161202170903-00046-ip-10-31-129-80.ec2.internal.warc.gz"} |
http://cdsweb.cern.ch/collection/ATLAS%20Conference%20Slides?ln=pl&as=1 | # CERN Accelerating science
The ATLAS Conference Slides collection contains transparencies on ATLAS that have been presented at conferences. More information about conferences can be found on the external ATLAS Talks at International Physics Conferences webpage.
SUBMIT ATLAS SLIDE
# ATLAS Conference Slides
Ostatnio dodane:
2019-11-15
18:29
Electroweak boson and forward jet probes of the initial state in Pb+Pb and p+Pb collisions with ATLAS / Sickles, Anne Marie (University of Illinois at Urbana-Champaign) /ATLAS Collaboration Measurements of electroweak bosons produced in Pb+Pb collisions as well as photon and jet production in p+Pb collisions are of great interest to understanding initial state effects. These channels are sensitive to a broad set of physics effects such as high-precision test of the binary collision scaling expected in Pb+Pb, the modification of the parton densities in nuclei, the onset of non-linear QCD or saturation effects at low-$x$, and the energy loss of partons in the nucleus before the hard scattering. [...] ATL-PHYS-SLIDE-2019-851.- Geneva : CERN, 2019 - 1 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : The 28th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions, Wuhan, China, 3 - 9 Nov 2019
2019-11-15
16:01
Implementation of the ATLAS trigger within the multi-threaded AthenaMT framework / Khoo, Teng Jian (Departement de Physique Nucleaire et Corpusculaire, Universite de Geneve) ; ATLAS Collaboration /ATLAS Collaboration Athena is the software framework used in the ATLAS experiment throughout the data processing path, from the software trigger system through offline event reconstruction to physics analysis. The shift from high-power single-core CPUs to multi-core systems in the computing market means that the throughput capabilities of the framework have become limited by the available memory per process. [...] ATL-DAQ-SLIDE-2019-850.- Geneva : CERN, 2019 - 25 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : 24th International Conference on Computing in High Energy and Nuclear Physics, Adelaide, Australia, 4 - 8 Nov 2019
2019-11-15
13:19
FELIX: the new detector interface for ATLAS / Panduro Vazquez, Jose Guillermo (Department of Physics, Royal Holloway and Bedford New College) ; ATLAS TDAQ Collaboration /ATLAS Collaboration After the current LHC shutdown (2019-2021), the ATLAS experiment will be required to operate in an increasingly harsh collision environment. To maintain physics performance, the ATLAS experiment will undergo a series of upgrades during the shutdown. [...] ATL-DAQ-SLIDE-2019-849.- Geneva : CERN, 2019 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : 24th International Conference on Computing in High Energy and Nuclear Physics, Adelaide, Australia, 4 - 8 Nov 2019
2019-11-15
13:17
Event-driven RDMA network communication in the ATLAS DAQ system with NetIO / Schumacher, Jorn (European Laboratory for Particle Physics, CERN) /ATLAS Collaboration Event-driven RDMA network communication in the ATLAS DAQ system with NetIO NetIO is a network communication library that enables distributed applications to exchange messages using high-level communication patterns such as publish/subscribe. NetIO is based on libfabric and supports various types of RDMA networks, for example Infiniband, RoCE, or OmniPath. [...] ATL-DAQ-SLIDE-2019-848.- Geneva : CERN, 2019 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : 24th International Conference on Computing in High Energy and Nuclear Physics, Adelaide, Australia, 4 - 8 Nov 2019
2019-11-15
11:18
The Performance of the Muon, Electron and Photon Trigger at ATLAS / Safarzadeh Samani, Batool (University of Sussex) /ATLAS Collaboration Events containing muons, electrons or photons in the final state are an important signature for many analyses being carried out at the Large Hadron Collider (LHC), including both standard model measurements and searches for new physics. To be able to study such events, it is required to have an efficient and well-understood trigger system. [...] ATL-DAQ-SLIDE-2019-847.- Geneva : CERN, 2019 - 14 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : 24th International Conference on Computing in High Energy and Nuclear Physics, Adelaide, Australia, 4 - 8 Nov 2019
2019-11-15
11:15
ATLAS Operational Monitoring Data Archival and Visualization / Soloviev, Igor (University of California, Irvine) ; Avolio, Giuseppe (European Laboratory for Particle Physics, CERN) ; Kazymov, Andrei (Joint Institute for Nuclear Research) ; Vasile, Matei Eugen (Horia Hulubei National Institute of Physics and Nuclear Engineering) /ATLAS Collaboration The Information Service (IS) is an integral part of the Trigger and Data Acquisition (TDAQ) system of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN. The IS allows online publication of operational monitoring data, and it is used by all sub-systems and sub-detectors of the experiment to constantly monitor their hardware and software components including more than 25000 applications running on more than 3000 computers. [...] ATL-DAQ-SLIDE-2019-846.- Geneva : CERN, 2019 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : 24th International Conference on Computing in High Energy and Nuclear Physics, Adelaide, Australia, 4 - 8 Nov 2019
2019-11-15
06:29
Disappearing track searches at LHC and future colliders / Sawada, Ryu (International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo) /ATLAS Collaboration Disappearing track searches at colliders, LHC (ATLAS/CMS), HL-LHC and FCC will be discussed. This talk will focus on the wino and higgsino dark matter.. ATL-PHYS-SLIDE-2019-845.- Geneva : CERN, 2019 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : Dark Matter searches in the 2020s At the crossroads of the WIMP, Kashiwa, Chiba, Japan, 11 - 13 Nov 2019
2019-11-14
02:01
Flow decorrelations in 5.44 TeV Xe+Xe collisions in ATLAS / Behera, Arabinda (Stony Brook University) /ATLAS Collaboration Longitudinal decorrelations of harmonic flow $v_n$ is measured for Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV using the ATLAS detector at the LHC. The decorrelation signal for $v_3$ and $v_4$ is found to be nearly independent of centrality percentiles and transverse momentum ($p_{\mathrm{T}}$), but has strong centrality and $p_{\mathrm{T}}$ dependence for $v_2$. [...] ATL-PHYS-SLIDE-2019-844.- Geneva : CERN, 2019 - 1 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2019-11-14
01:46
ATLAS measurements of collective flow of heavy-flavor hadrons in small collision systems / Lim, Sanghoon (University of Colorado Boulder) /ATLAS Collaboration ATLAS measurements of azimuthal anisotropy of heavy flavor mesons in the small systems is presented. A template fit method is used to subtract non-flow contributions using simultaneous fit to low and high charged particle multiplicity samples. [...] ATL-PHYS-SLIDE-2019-843.- Geneva : CERN, 2019 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : The 28th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions, Wuhan, China, 3 - 9 Nov 2019
2019-11-13
09:25
Measurements of electroweak boson tagged jet energy loss and modification by ATLAS / Perepelitsa, Dennis (University of Colorado Boulder) /ATLAS Collaboration Measurements of reconstructed jets produced in conjunction with a high- ATL-PHYS-SLIDE-2019-842.- Geneva : CERN, 2019 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : The 28th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions, Wuhan, China, 3 - 9 Nov 2019 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9380947351455688, "perplexity": 8720.770878706193}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668765.35/warc/CC-MAIN-20191116204950-20191116232950-00431.warc.gz"} |
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[1] Do Duc Thai and Tran Ngoc Giao. The convergence-extension theorem of Noguchi in infinite dimensions. Proc. Amer. Math. Soc. 130 (2002) 477-482. MR 1862128. Abstract, references, and article information View Article: PDF This article is available free of charge [2] Shulim Kaliman and Mikhail Zaidenberg. Non-hyperbolic complex space with a hyperbolic normalization. Proc. Amer. Math. Soc. 129 (2001) 1391-1393. MR 1814164. Abstract, references, and article information View Article: PDF This article is available free of charge [3] James E. Joseph and Myung H. Kwack. A generalization of a theorem of Heins . Proc. Amer. Math. Soc. 128 (2000) 1697-1701. MR 1641112. Abstract, references, and article information View Article: PDF This article is available free of charge [4] Wlodzimierz Zwonek. On Carathéodory completeness of pseudoconvex Reinhardt domains. Proc. Amer. Math. Soc. 128 (2000) 857-864. MR 1646214. 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Abstract, references, and article information View Article: PDF This article is available free of charge [24] Kyong T. Hahn. Equivalence of the classical theorems of Schottky, Landau, Picard and hyperbolicity . Proc. Amer. Math. Soc. 89 (1983) 628-632. MR 718986. Abstract, references, and article information View Article: PDF This article is available free of charge [25] Morris Kalka. Measures associated to Chern, Levine and Nirenberg norms . Proc. Amer. Math. Soc. 88 (1983) 404-406. MR 699403. Abstract, references, and article information View Article: PDF This article is available free of charge [26] Theodore J. Barth. The Kobayashi indicatrix at the center of a circular domain . Proc. Amer. Math. Soc. 88 (1983) 527-530. MR 699426. Abstract, references, and article information View Article: PDF This article is available free of charge [27] Scott Wolpert. A generalization of the Ahlfors-Schwarz lemma . Proc. Amer. Math. Soc. 84 (1982) 377-378. MR 640235. Abstract, references, and article information View Article: PDF This article is available free of charge [28] Kyong T. Hahn. Inequality between the Bergman metric and Carath\'eodory differential metric . Proc. Amer. Math. Soc. 68 (1978) 193-194. MR 0477166. Abstract, references, and article information View Article: PDF This article is available free of charge [29] Jacob Burbea. Inequalities between intrinsic metrics . Proc. Amer. Math. Soc. 67 (1977) 50-54. MR 0481121. Abstract, references, and article information View Article: PDF This article is available free of charge [30] T. Duchamp and M. Kalka. Holomorphic foliations and the Kobayashi metric . Proc. Amer. Math. Soc. 67 (1977) 117-122. MR 0464258. Abstract, references, and article information View Article: PDF This article is available free of charge
Results: 1 to 30 of 40 found Go to page: 1 2 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9504256844520569, "perplexity": 1728.127652430574}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-35/segments/1408500834663.62/warc/CC-MAIN-20140820021354-00069-ip-10-180-136-8.ec2.internal.warc.gz"} |
http://tex.stackexchange.com/questions/46602/footnote-in-the-column-name-of-a-table/47413 | # footnote in the column name of a table [duplicate]
Possible Duplicate:
Footnotes in tables?
I tried inserting \footnote in the column name of a table. The footnote did not appear at the bottom of the page as expected. Can someone help me?
A sample code is provided below:
\begin{table}[htbp]
\centering
\scriptsize
\begin{tabular}{|c|c|c|c|c|}
\hline
\textbf{Queries} & \textbf{NUR}\footnote{No of unigram models satisfying user
preference} & \textbf{NBR}\footnote{No of bigram models satisfying user
preference} & \textbf{UCHR}\footnote{class hit rate for unigram models} &
\textbf{BCHR}\footnote{class hit rate for bigram models} \\
-
## marked as duplicate by egreg, Werner, lockstep, Stefan Kottwitz♦Apr 24 '12 at 16:38
Tables are usually furnished with table notes. If you show some code in form of a minimal example, specific help will be much easier. – Thorsten Donig Mar 3 '12 at 10:57
I have uploaded sample code – user12275 Mar 3 '12 at 11:12
read the FAQ: tex.ac.uk/cgi-bin/texfaq2html?label=footintab – Herbert Mar 3 '12 at 11:16
A full example as requested would be much more helpful. – Thorsten Donig Mar 3 '12 at 13:34
Some related/duplicate questions Footnotes in Tables and Footnotes in tabulars. – Alan Munn Mar 3 '12 at 14:41
You can use the tablefootnote package with \tablefootnotes inside the table instead of ordinary \footnotes:
\documentclass{article}
%\usepackage{hyperref}% if you use hyperref, load it before tablefootnote
\usepackage{tablefootnote}
\begin{document}
\begin{table}[htbp]
\centering
\scriptsize
\begin{tabular}{|c|c|c|c|c|}
\hline
\textbf{Queries} & \textbf{NUR}\tablefootnote{No of unigram models satisfying user
preference} & \textbf{NBR}\tablefootnote{No of bigram models satisfying user
preference} & \textbf{UCHR}\tablefootnote{class hit rate for unigram models} &
\textbf{BCHR}\tablefootnote{class hit rate for bigram models} \\
\hline
\end{tabular}
\end{table}
% \newpage
% for making easier the testing of the hyperlinks
\end{document}
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http://stfi.ru/en/issues/2020/02/STFI_2020_02_MorozovEA.html | 2020, no. 2
### ON THE USE OF BIVECTOR FORMALIZM IN HAMILTONIAN MECHANICS
#### Morozov E. A., Morozova A.R., Morozova L.E
A bivector formalism of Hamiltonian mechanics is constructed. The extended affine space of impulses, coordinates, and time is determined based on the determinism principle. The space attached to it is considered as a direct sum of the covariant space of pulses and the contravariant space of coordinates and time, after which the bivector space of pulses, coordinates and time is determined. The resulting point-bivector correspondence allows us to determine the corresponding extended phase space and flow. It turns out that the bivector analog of the dynamic Hamilton equations has the form of the dynamic Newton equation for the potential field. We consider a bivector variant of canonical transformations that define the geometry of a bivector phase space. The use of covariant and contravariant vector spaces, as well as basic tensor operations, makes it possible to significantly simplify the transformation algebra in proofs.
Keywords: Hamilton mechanics, Hamilton equations, phase space, canonical transformations.
UDC: 531.011
PACS: 04.50.Kd
DOI: 10.17238/issn2226-8812.2020.2.64-70 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9584131836891174, "perplexity": 920.7491154502652}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030335365.63/warc/CC-MAIN-20220929194230-20220929224230-00468.warc.gz"} |
http://mathoverflow.net/questions/4125/if-spec-z-is-like-a-riemann-surface-whats-the-analogue-of-integration-along-a-c/4141 | ## If Spec Z is like a Riemann surface, what’s the analogue of integration along a contour?
Rings of functions on a nonsingular algebraic curve (which, over C, are holomorphic functions on a compact Riemann surface) and rings of integers in number fields are both examples of Dedekind domains, and I've been trying to understand the classical analogy between the two. As I understand it, should be thought of as the curve / Riemann surface itself. Is there a good notion of integration in this setting? Is there any hope of recovering an analogue of the Cauchy integral formula?
(If I am misunderstanding the point of the analogy or stretching it too far, please let me know.)
-
For a variety $X$ over a finite field, I guess one can take $\ell$-adic sheaves to replace differential forms. Then the local integral around a closed point $x$ (like integral over a little loop around that point) is the trace of the local Frobenius $Frob_x$ on the stalk of sheaf, the so-called naive local term. Note that $Frob_x$ can be regarded as an element (or conjugacy class) in $\pi_1(X)$, "a loop around $x$". The global integral would be the global trace map $$H^{2d}_c(X,\mathbf{Q}_{\ell})\to\mathbf{Q}_{\ell}(-d),$$ and the Tate twist is responsible for the Hodge structure in Betti cohomology (or the $(2\pi i)^d$ one has to divide by). The Lefschetz trace formula might be the analog of the residue theorem in complex analysis on Riemann surfaces.
For the case of number fields, each closed point $v$ in $Spec\ O_k$ still defines a "loop" $Frob_v$ in $\pi_1(Spec\ k)$ (let's allow ramified covers. One can take the image of $Frob_v$ under $\pi_1(Spec\ k)\to\pi_1(Spec\ O_k)$, but the target group doesn't seem to be big enough). For global integral, there's the Artin-Verdier trace map $H^3(Spec\ O_k,\mathbb G_m)\to\mathbb{Q/Z}$ and a "Poincar\'e duality" in this setting, but I don't know if there is a trace formula. The fact that 3 is odd always makes me excited and confused.
So basically I think of trace maps (both local and global) as counterpart of integrals. Correct me if I was wrong.
-
This is interesting, but a little over my head. If you don't mind, could you explain how one thinks about the contour integral in this abstract setting, i.e. in terms of the fundamental group? – Qiaochu Yuan Nov 4 2009 at 19:58
A loop in this setting is a map from a scheme with a "cyclic" fundamental group. Finite fields have this property, so their spectra can be viewed as circles. For Spec Z, the only interesting loops we see are the canonical maps from spectra of finite fields. One has an analogy between integration of differentials and parallel transport along connections, so we are determining how a vector bundle (our l-adic sheaf) is transformed as we follow flat sections around a "circle". – S. Carnahan Nov 5 2009 at 2:37
"The fact that 3 is odd always makes me excited and confused." Fantastic. – Cam McLeman May 8 2011 at 18:56
I think that you have understood the analogy correctly, and you have pinpointed one of its weaknesses. Although number fields are like one dimensional functional fields in many ways, one of the differences is that the vector space of Kahler differentials for a number field has dimension 0, not 1. Here Kahler differentials are the vector space generated by symbols dx, subject to the relations d(x+y) = dx + dy and d(xy) = x dy + y dx.
Therefore, there is nothing like differentials, and nothing we can integrate.
But it is possible that there is some more sophisticated way to solve this problem. (Maybe using Arakelov geometry?) I'm looking forward to reading the other answers.
-
This certainly does have a bit of the Arakelov smell about it. Maybe if you include the infinite places there's some different notion of Kahler differential? – Ben Webster Nov 4 2009 at 18:40
That makes sense; it's related to the fact that the abc conjecture is much harder than the Mason-Stothers theorem. I think a lot of people would want to see a notion of differential in the number field setting for this reason. – Qiaochu Yuan Nov 4 2009 at 18:45
I think David's module of differentials on R should include the rule that dc = 0 when c is a constant: here the ring of constants is some specified subring R_0 of R. (So e.g. when R = C[t] one takes R_0 = C; otherwise, the differentials are way bigger than you want.) So we see the problem: David's module is Omega_{Z/Z}, and the relative dimension is 0, while for Omega_{C[t]/C} the relative dimension is 1. In order to have a good notion of differentials you'd need a "field of constants" "inside" Spec Z, which would have... oh, I dunno.... one element? – JSE Nov 5 2009 at 1:31
Yup! JSE's comment is exactly right, and gives a great way of seeing why we want a field with one element. – David Speyer Nov 5 2009 at 1:38
Lichtenbaum talked about that and interesting applications last December: institut.math.jussieu.fr/projets/tn/STN/11/… – Thomas Riepe May 8 2011 at 15:05
For a number f the local-global formula written as
where is the inverse power of p that is equal to f in the local field of p-adic numbers and is f should provide a reasonable analogue (in other words, integration over all holes gives 0 on a closed surface).
(An example for f = 75: 1 * 1/3 * 1/25 * 1 * ...* 75 = 1)
A better formulation would involve adeles: the adele ring is a semi-restricted product of p-adic rationals and rationals themselves. There is a map and every element in the image has the property that the product over all places gives 1.
-
I think we have to be careful about the two senses of the word "residue" here. Either way my hope was that one could recover the residue as part of a more general computation. – Qiaochu Yuan Nov 4 2009 at 18:43
I'm rewriting the answer and making it better. I remember things one by one, but there should definitely be a good answer! – Ilya Nikokoshev Nov 4 2009 at 18:54
I take the product formula as an analog of the fact that a principal divisor on a curve has degree 0, so it is a (at least special case of the) residue theorem: the local integral at all points add up to the integral over the boundary, and there's no boundary if we also include \infty! – shenghao Nov 4 2009 at 19:59
That's absolutely what I mean, yes. – Ilya Nikokoshev Nov 4 2009 at 20:56 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9362817406654358, "perplexity": 393.2906895211812}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368706082529/warc/CC-MAIN-20130516120802-00029-ip-10-60-113-184.ec2.internal.warc.gz"} |
https://forum.bebac.at/forum_entry.php?id=17962 | ## critical values [Nonparametrics]
Hi Václav and GM,
see also this rather old post with tables of the positions of the lower critical values and exact probabilities for m=n=3–32. Generally the normal approximation should not be used if m <8 or n <8.
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9327317476272583, "perplexity": 3393.9426409945886}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296949107.48/warc/CC-MAIN-20230330070451-20230330100451-00512.warc.gz"} |
http://math.stackexchange.com/questions/238659/continuous-function-proof-help | Continuous function proof help
Let $f : [a, b]\to R$ be a continuous function such that $[a,b] \subset [f(a), f(b)]$. Prove that there exists $x\in [a,b]$ such that $f(x) = x$.
My attempt: I said let there be a $\delta > 0$and defined $c$ and $d$ to be $x + \delta$ and $x-\delta$ respectively. From here since $f$ is continuous $[f(c), f(d)]\subset [f(a), f(b)]$. Then I assumed by definition $[c,d]$ is also a subset of $[f(c), f(d)]$. Then I claimed $\delta$ can be arbitrarily small so that $f(c) = f(d) = f(x)$.
Is this correct or is there a better approach?
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If $[a,b]\cap [f(a),f(b)]=\emptyset$ then for any function $f:[a,b]\to \mathbb{R}$ (with this property) there is no such $x^*$. – vesszabo Nov 16 '12 at 13:23
It's not necessarily true that $[f(c),f(d)]$ is a subset of $[f(a),f(b)]$. Consider a function where $f(0) = 0$, $f(1) = (1)$ where $f(x)$ starts decreasing at $0$. – Jason DeVito Nov 16 '12 at 13:28
Your approach is not correct, since you are assuming what you are supposed to show. You cannot define $c$ and $d$ to be something which depends on $x^*$ before you have shown that there is such a number as $x^*$.
A better approach would be to consider the function $g(x)=f(x)-x$. Argue that $g$ is continuous, that $g(a)\leq 0$, and that $g(b)\geq 0$. Then there should be a result available that you can use.
-
I see. I'm trying to show $g(a)\leq 0$ but I'm having a hard time seeing how knowing $[a,b] \subset [f(a), f(b)]$ will help. I only know it is a subset and can't say much about their values. – Vincent Nov 16 '12 at 13:56
Try to draw the two intervals along a real line. What must the order of the four points be? What does that tell you about the size of $a$ and $f(a)$? – Per Manne Nov 16 '12 at 14:00
I know that $a < b$ and that $f(a) < f(b)$. But isn't it still possible for either $a$ to be greater than $f(a)$ or vice versa? – Vincent Nov 16 '12 at 14:08
Did you draw the two intervals with one being contained in the other? Try to find a numerical example where $[a,b]\subset [f(a),f(b)]$ and $a<f(a)$. (Hint: It can't be done.) – Per Manne Nov 16 '12 at 14:32
In $\mathbb R^2$ draw the straight line $y=x$ and consider any interval at the positive part of $x$-axis, you'll get some intuition. Your problem is saying that under some conditions the graph of your function is going to intersept the straight line $y=x$ in some point. Think about the conditions for it to happen..
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https://www.biostars.org/p/471438/ | Detection P-value in illumina data
1
0
Entering edit mode
9 months ago
parinv ▴ 30
hello,
I have started to work with an Illumina dataset [platform:-GPL10558-Illumina HumanHT-12 V4.0 expression beadchip]. I don't have any prior knowledge of Illumina data analysis. I imported my file to R-studio using lumiR function of the Lumi package but the data has some sample replicate and Detection P-value.
Can anyone suggest how I remove these replicate samples and analyze the Illumina data with P-values in it? Do I need to remove the detection P-value or use them in the analysis?
Thank you
Parin
R illumina microarray data • 545 views
1
Entering edit mode
9 months ago
Based on voting patterns, it seems that you found some other posts on this topic. Is this correct?
0
Entering edit mode
yes, I found some questions related to illumina data but that did not clear my confusion regarding the detection P value.
1
Entering edit mode
You can use the detection p-value to filter out probes that failed. This is reported in the limma manual, I think.
0
Entering edit mode
After filtering the probes, should we remove the detection p-value columns or keep them for further analysis?
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Entering edit mode
You will not need them for anything that is downstream of the probe filtering
0
Entering edit mode
Thankyou Kevin, I just have one last question. I Came across some papers, in which they filtered probes before background correction. Can you please explain if it is the correct way to filter probes and why should we background correct the data and then filter probes?
1
Entering edit mode
Please elaborate on which specific filtering was performed in the papers that you mention.
The detection p-values are used during normalisation to determine precisely those probes that provide reliable signal. Please see the entire pipeline (advanced) which I posted recently: A: GPL6883_HumanRef-8_V3_0_R0_11282963_A (illumina expression beadchip)
Background correction and normalisation is performed via the neqc() function, which takes into account the detection p-values if the input object is setup correctly - it will issue a message to terminal stating just this.
1
Entering edit mode
thank you so much Kevin for your help. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.23653432726860046, "perplexity": 3540.42293944862}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046155322.12/warc/CC-MAIN-20210805032134-20210805062134-00716.warc.gz"} |
http://333.tunehenge.com/frog-got-a-lizard/ | # Frog Got A Lizard
Frog got a lizard and won’t let go
Sit right down l got a story to tell
Back in the bayou under a half moon sky
Some old jazz sliding from a nearby shack
and frog eye’n a lizard who was walking by
Chorus
Frog got a lizard and he won’t let go
Frog got a lizard and he won’t let go
Swinging her till the cows come home
Dancing em all ‘n stealing the show
Frog got a lizard and he won’t let go
Ohh Frog got a lizard and he won’t let go
Is not every day you see a thing like that
He’s got the moves look at him what a sight
Swinging her around on the big dance floor
A frog and a lizard staying up all night
Chorus
Frog got a lizard and he won’t let go
Ohh Frog got a lizard and he won’t let go
Swinging her till the cows come home
Dancing em all ‘n stealing the show
Frog got a lizard and he won’t let go
Ohh Frog got a lizard and he won’t let go
Frog got a lizard and he won’t let go
Ohh Frog got a lizard and he won’t let go
Swinging her till the cows come home
Dancing em all ‘n stealing the show
Frog got a lizard and he won’t let go
## One thought on “Frog Got A Lizard”
1. Joel D Canfield says:
We already know this is a brilliant song. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9548529982566833, "perplexity": 15292.993587424284}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-13/segments/1552912202572.29/warc/CC-MAIN-20190321193403-20190321215403-00292.warc.gz"} |
http://mathoverflow.net/questions/102453/map-with-prescribed-jacobian | # Map with prescribed Jacobian
Recently I came up with the following problem.
Suppose $U$ is an open subset of $\mathbb{R}^n$ and we are given a continuous map $M:U\to GL(n;\mathbb{R})$. Does anybody know if there are conditions for the existence of a $C^1$ map $f:U\to \mathbb{R}^n$ such that $$Jf(x)=M(x)\quad \forall x \in U$$ (here $Jf(x)$ is the Jacobian matrix of $f$ at $x$)?
I know this question is somehow a little bit general; I will really appreciate even a reference for something related to this problem. :)
-
Suppose we can find such an $f$. If $f$ is continuously differentiable, then the i'th row and j'th column of the Jacobian (in the standard basis) is the j'th partial derivative of the the i'th component of $f$. Indeed, the components of $f$ are continuously differentiable if and only if $f$ is. So it suffices to consider each of the components of $f$ along with its corresponding row in M(x) seperately - i.e. we want $\nabla f_{i}=M_{i}$ where $M_{i}$ is the i'th row of $M$. So the ith row of $M$ is given by a scalar potential - e.g. if $M$ is (continuously) differentiable $\omega_{i}=\sum_{j}m_{i,j}dx^{j}$ is exact, where $M(x)=(m_{i,j}(x))$. A neccesary condition for this to be true is $\partial_{k}m_{i,j}=\partial_{j}m_{i,k}$ for all $i,j,k\in\{1,..n\}$. The sufficiency of this condition depends on the topology of $U$. See http://en.wikipedia.org/wiki/Closed_and_exact_differential_forms.
This is a nice answer, though somehow tautological. Also notice that we are not allowed to take derivatives of the matrix $M$ since it is assumed to depend only continuously on $x.$ – A. Lerario Jul 17 '12 at 15:52
Why is this "somehow tautological"? Also, the derivatives of $M$ do exist in the weak or distributional sense and the answer remains valid using that. – Deane Yang Jul 17 '12 at 16:07
Maybe another thing to notice (maybe its obvious) is that $M$ is invertible on all of $U$. So if such an f exists, the inverse function theorem guarantees that it is a local $C^{1}$ diffeomorphism. – Brian Trundy Jul 17 '12 at 16:07
So if such an $f$ exists, there is (at least locally) a $C^{1}$ map $g$ satifying $Dg(x)=M^{-1}(f(x))$. This suggests that there should be a further restriction on the components of $M$ (Using Cramer's Rule to get the components of $M^{-1}$ in terms of the components of $M$) in terms of weak/distributional derivatives. – Brian Trundy Jul 17 '12 at 16:56 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9542188048362732, "perplexity": 103.95599218122273}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-35/segments/1408500834663.62/warc/CC-MAIN-20140820021354-00088-ip-10-180-136-8.ec2.internal.warc.gz"} |
https://projecteuclid.org/euclid.imsc/1379942050 | ## Institute of Mathematical Statistics Collections
### Sampling from a Manifold
#### Abstract
We develop algorithms for sampling from a probability distribution on a submanifold embedded in $\mathbb{R}^{n}$. Applications are given to the evaluation of algorithms in ‘Topological Statistics’; to goodness of fit tests in exponential families and to Neyman’s smooth test. This article is partially expository, giving an introduction to the tools of geometric measure theory.
#### Chapter information
Source
Galin Jones and Xiaotong Shen, eds., Advances in Modern Statistical Theory and Applications: A Festschrift in honor of Morris L. Eaton, (Beachwood, Ohio, USA: Institute of Mathematical Statistics, 2013) , 102-125
Dates
First available in Project Euclid: 23 September 2013
https://projecteuclid.org/euclid.imsc/1379942050
Digital Object Identifier
doi:10.1214/12-IMSCOLL1006
Zentralblatt MATH identifier
1356.62015
Rights
#### Citation
Diaconis, Persi; Holmes, Susan; Shahshahani, Mehrdad. Sampling from a Manifold. Advances in Modern Statistical Theory and Applications: A Festschrift in honor of Morris L. Eaton, 102--125, Institute of Mathematical Statistics, Beachwood, Ohio, USA, 2013. doi:10.1214/12-IMSCOLL1006. https://projecteuclid.org/euclid.imsc/1379942050
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• Yang, Z. (2006). Computational Molecular Evolution. Oxford University Press, Oxford. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5193598866462708, "perplexity": 3907.5477041058884}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986649841.6/warc/CC-MAIN-20191014074313-20191014101313-00341.warc.gz"} |
https://socialsci.libretexts.org/Bookshelves/Anthropology/Linguistics/Book%3A_Essentials_of_Linguistics_(Anderson)/02%3A_Producing_Speech_Sounds/2.07%3A_Articulators | # 2.7: Articulators
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Speaking involves controlling parts of the mouth and nose to shape the air that comes from the lungs. This unit introduces the names and locations of the articulators that are used to produce the sounds of English: the tongue, lips and teeth, the alveolar ridge, the palate, the velum, and the nasal cavity.
A YouTube element has been excluded from this version of the text. You can view it online here: ecampusontario.pressbooks.pu...guistics/?p=40
## Check Yourself
1. Which articulators are responsible for the first sound in the word minor?
• Lips.
• Lips and teeth.
• Tongue and teeth.
• Tongue and alveolar ridge.
• Tongue and palate.
• Tongue and velum.
2. Which articulators are responsible for the final sound in the word wit?
• Lips.
• Lips and teeth.
• Tongue and teeth.
• Tongue and alveolar ridge.
• Tongue and palate.
• Tongue and velum.
3. Which articulators are responsible for the first sound in the word photography?
• Lips.
• Lips and teeth.
• Tongue and teeth.
• Tongue and alveolar ridge.
• Tongue and palate.
• Tongue and velum. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.236881822347641, "perplexity": 5318.664288982933}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882573876.92/warc/CC-MAIN-20220820012448-20220820042448-00521.warc.gz"} |
https://export.arxiv.org/abs/2110.11627 | cs.IT
(what is this?)
# Title: On the largest singular values of certain large random matrices with application to the estimation of the minimal dimension of the state-space representations of high-dimensional time series
Authors: Daria Tieplova (LIGM), Philippe Loubaton (LIGM)
Abstract: This paper is devoted to the estimation of the minimal dimension P of the state-space realizations of a high-dimensional time series y, defined as a noisy version (the noise is white and Gaussian) of a useful signal with low rank rational spectral density, in the high-dimensional asymptotic regime where the number of available samples N and the dimension of the time series M converge towards infinity at the same rate. In the classical low-dimensional regime, P is estimated as the number of significant singular values of the empirical autocovariance matrix between the past and the future of y, or as the number of significant estimated canonical correlation coefficients between the past and the future of y. Generalizing large random matrix methods developed in the past to analyze classical spiked models, the behaviour of the above singular values and canonical correlation coefficients is studied in the high-dimensional regime. It is proved that they are smaller than certain thresholds depending on the statistics of the noise, except a finite number of outliers that are due to the useful signal. The number of singular values of the sample autocovariance matrix above the threshold is evaluated, is shown to be almost independent from P in general, and cannot therefore be used to estimate P accurately. In contrast, the number s of canonical correlation coefficients larger than the corresponding threshold is shown to be less than or equal to P, and explicit conditions under which it is equal to P are provided. Under the corresponding assumptions, s is thus a consistent estimate of P in the high-dimensional regime. The core of the paper is the development of the necessary large random matrix tools.
Subjects: Information Theory (cs.IT); Probability (math.PR) Cite as: arXiv:2110.11627 [cs.IT] (or arXiv:2110.11627v1 [cs.IT] for this version)
## Submission history
From: Philippe Loubaton [view email]
[v1] Fri, 22 Oct 2021 07:21:34 GMT (151kb,D)
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http://mathhelpforum.com/advanced-statistics/175589-queueing-query-maple-print.html | # Queueing Query with Maple
• March 23rd 2011, 04:09 PM
MathSucker
Queueing Query with Maple
I have a queue with 1000 time intervals.
The average length over 1000 intervals was 2.718
I'm looking for the probabilities that a given state will jump up, $p_1$, or down, $p_2$
I ran the following through maple to count the number of times the queue moved up or down (qdata is the list of 1000 queue values):
nup:=0;
ndown:=0;
for i from 1 to 999 do
if qdata[i+1]>qdata[i] then
nup:=nup+1;
elif qdata[i+1]<qdata[i] then
ndown:=ndown+1;
end if;
end do:
p1:=evalf(nup/1000);
p2:=evalf(ndown/1000);
I ended up with $p_1 = 417$ and $p_2 =421$
I'm wondering if there is a problem here. Am I not taking into account when the queue length is zero and it has no probability of moving down?
Would it make sense to add this into the do loop:
elif qdata[i]=0 then
ndown:=ndown-1;
Or does the original code give the proper values? Am I missing something?
• March 23rd 2011, 05:05 PM
MathSucker | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 4, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.40715092420578003, "perplexity": 1614.766586458972}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246656168.61/warc/CC-MAIN-20150417045736-00146-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://www.gradesaver.com/textbooks/math/algebra/introductory-algebra-for-college-students-7th-edition/chapter-5-section-5-1-adding-and-subtracting-polynomials-exercise-set-page-348/33 | # Chapter 5 - Section 5.1 - Adding and Subtracting Polynomials - Exercise Set: 33
$10x^{3}$ + 1
#### Work Step by Step
(9$x^{3} - x^{2}- x - \frac{1}{3}$) + ($x^{3} + x^{2} + x + \frac{4}{3}$) The like terms are 9$x^{3}$ and $x^{3}$(both containing $x^{3}$) , -$x^{2}$ and $x^{2}$ (both containing $x^{2}$) , -x and x (both containing r) , -$\frac{1}{3}$ and $\frac{4}{3}$ both are constants We begin by grouping these pairs of like terms = (9$x^{3}$ + $x^{3}$) + (-$x^{2}$ + $x^{2}$) + (-x + x)+ (-$\frac{1}{3}$ + $\frac{4}{3}$) =$10x^{3}$ + 1
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5772258043289185, "perplexity": 1858.8828832699196}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-30/segments/1531676592420.72/warc/CC-MAIN-20180721071046-20180721091046-00264.warc.gz"} |
https://www.physicsforums.com/threads/increment-or-decrement-a-parameter-in-latex.354839/ | # Increment (or decrement) a parameter in LaTeX
1. Nov 14, 2009
### robbins
How can I increment or decrement a parameter in LaTeX?
For example, suppose I create an environment foo as follows:
\newenvironment{foo}[2]{\begin{tabular}{*{#1}c*{#2}r}}{\end{tabular}}
I can write
\begin{foo}{4}{3}
<tabular data in seven columns>
\end{foo}
But in my application, if the first parameter is n, then second is always n-1. Is there a way to write this that passes only one parameter (in this case n), but which will produce the table with n + (n - 1) columns as in the environment foo?
Decrementing the parameter #1 inside the newenvironment -- if it is possible -- would surely work, but I don't know how to do it.
Note: The snippet
\let\temp#1
\advance\temp by -1
doesn't work because if I pass the parameter 4, \temp takes the value 'the character 4', which can't follow the \advance command.
I'm stuck. Any help?
2. Nov 16, 2009
### robbins
This solution was posted by Joseph Wright on LaTeX Community:
"You don't want \let, you want to do things with numbers proper. The thing is that they then [need] to be assigned to TeX counters. You seem to want something like
\newcount\mycount
\newenvironment{foo}[1]
{%
\mycount #1\relax
\advance\mycount -1\relax
\begin{tabular}{*{#1}c*{\the\mycount}r}%
}
{\end{tabular}}
Here, I'm using a TeX count register to do the maths. You can do the same with a LaTeX counter, but I find this route a bit easier for going downward. TeX assigns count registers locally, so the above should work in most cases."
Thanks, Joseph.
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https://www.physicsforums.com/threads/discrete-metric-and-continuity-equivalence.710512/ | # Discrete metric and continuity equivalence
• Start date
• #1
mahler1
222
0
Homework Statement .
Prove that a metric space X is discrete if and only if every function from X to an arbitrary metric space is continuous.
The attempt at a solution.
I didn't have problems to prove the implication discrete metric implies continuity. Let f:(X,δ)→(Y,d) where (Y,d) is an arbitrary metric space. Let V be an open set in (Y,d). Every set in X is open so, in particular, f^-1(V) is an open set. This proves f is continuous.
I don't know how to prove the other statement: if every function from the metric space X to some arbitrary metric space Y is a continuous function, then X is discrete.
• #2
Homework Helper
2,273
877
Homework Statement .
Prove that a metric space X is discrete if and only if every function from X to an arbitrary metric space is continuous.
The attempt at a solution.
I didn't have problems to prove the implication discrete metric implies continuity. Let f:(X,δ)→(Y,d) where (Y,d) is an arbitrary metric space. Let V be an open set in (Y,d). Every set in X is open so, in particular, f^-1(V) is an open set. This proves f is continuous.
I don't know how to prove the other statement: if every function from the metric space X to some arbitrary metric space Y is a continuous function, then X is discrete.
Proof by contrapositive: Suppose X is not discrete. Then there exists a function from X to {0,1} which is not continuous.
Likes 1 person
• #3
mahler1
222
0
Proof by contrapositive: Suppose X is not discrete. Then there exists a function from X to {0,1} which is not continuous.
Thanks for the advice. I've come up with this idea but I want to check if it is ok:
Suppose X is not discrete. Take (Y,d') to be the Y={0,1} and d'=δ distance. By definition of discrete space, if X is not discrete then there exists some x for which for all ε>0, the ball B(x,ε) contains other point y different from x. Define f to be f(x)=0 and f(y)=1 for all y in X with y≠x. If f is continuous, in particular, is continuous at the point x. Take ε'=1/2. Then, for all ε, there is some y such that d(x,y)<ε but δ(f(x),f(y))=δ(1,0)=1>1/2=ε'. But this is absurd since f was continuous. Then X must be discrete.
I have a question regarding the concept of discrete space. If the derived set of some metric space is empty, is this equivalent to say that X is discrete? I think it is but I'm not 100% sure. If this equivalence holds, I have a similar proof to the original problem:
Suppose X is not discrete, then there exists x in X'. Take (Y,d')=({0,1},δ) and define f(x)=0 and f(y)=1 for all y in X-{x}. By definition of derived set, there exists a sequence {x_n} in X such that x_n→x when n→∞. The function f is continuous, so f(x_n)→f(x) when n→∞. But f(x_n)=1≠0=f(x), which is absurd. It follows that X must be discrete.
• #4
Homework Helper
26,263
619
Thanks for the advice. I've come up with this idea but I want to check if it is ok:
Suppose X is not discrete. Take (Y,d') to be the Y={0,1} and d'=δ distance. By definition of discrete space, if X is not discrete then there exists some x for which for all ε>0, the ball B(x,ε) contains other point y different from x. Define f to be f(x)=0 and f(y)=1 for all y in X with y≠x. If f is continuous, in particular, is continuous at the point x. Take ε'=1/2. Then, for all ε, there is some y such that d(x,y)<ε but δ(f(x),f(y))=δ(1,0)=1>1/2=ε'. But this is absurd since f was continuous. Then X must be discrete.
I have a question regarding the concept of discrete space. If the derived set of some metric space is empty, is this equivalent to say that X is discrete? I think it is but I'm not 100% sure. If this equivalence holds, I have a similar proof to the original problem:
Suppose X is not discrete, then there exists x in X'. Take (Y,d')=({0,1},δ) and define f(x)=0 and f(y)=1 for all y in X-{x}. By definition of derived set, there exists a sequence {x_n} in X such that x_n→x when n→∞. The function f is continuous, so f(x_n)→f(x) when n→∞. But f(x_n)=1≠0=f(x), which is absurd. It follows that X must be discrete.
That sounds fine. Both of those proofs are really the same. Why are you not 100% sure that the set of all limit points of a metric space is empty if and only if the space is discrete? You should be able to prove that. And for your first proof, since you have 'if and only if' you still have to prove any function on a discrete space is continuous. But that should be pretty easy. Actually, I see you've already gotten that part. Nevermind.
Last edited:
Likes 1 person
• #5
Homework Helper
2,273
877
Thanks for the advice. I've come up with this idea but I want to check if it is ok:
Suppose X is not discrete. Take (Y,d') to be the Y={0,1} and d'=δ distance. By definition of discrete space, if X is not discrete then there exists some x for which for all ε>0, the ball B(x,ε) contains other point y different from x. Define f to be f(x)=0 and f(y)=1 for all y in X with y≠x. If f is continuous
You don't need to derive a contradiction; you can show directly that f as defined is not continuous at x:
If $\epsilon < d'(0,1)$ then for every $\delta > 0$ there exists $y \in B(x,\delta)$ with $d'(f(x),d(y)) > \epsilon$ and thus $f$ is not continuous at $x$.
That's sufficient to complete the proof: the object is to show that if X is not discrete then there exists a metric space Y such that there exists a function from X to Y which is not continuous, which is equivalent to showing that if every function from X to an arbitrary metric space is continuous then X is discrete.
A direct proof would probably start with the observations that if every function from X to an arbitrary metric space is continuous then every function from X to {0,1} is continuous, and that every such function can be written as
$$f : x \mapsto \left\{\begin{array}{rc} 0 & \mbox{ if } x \in U \\ 1 & \mbox{ otherwise} \end{array} \right.$$
for some $U \subset X$.
• #6
mahler1
222
0
You're right. I've messed up with logic. We've shown that the contrapositive is true, so the statement is true.
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989 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9774895310401917, "perplexity": 339.6053596601184}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882573399.40/warc/CC-MAIN-20220818185216-20220818215216-00255.warc.gz"} |
https://idoc.ias.u-psud.fr/MEDOC/Publications?page=7 | # List of Articles using MEDOC resources
Non-Lte Modelling of the EUV Filament Based on Soho/sumer Observations of the Hydrogen Lyman Lines, , The Dynamic Sun: Challenges for Theory and Observations, Dec, Volume 600, (2005) Effect of the H I Lyα Chromospheric Flux Anisotropy on the Total Intensity of the Resonantly Scattered Coronal Radiation, Auchère, F. , Astrophysical Journal, Mar, Volume 622, p.737-743, (2005) Solar Hydrogen Lyman Contimuum Observations with Soho/sumer, , The Dynamic Sun: Challenges for Theory and Observations, Dec, Volume 600, (2005) Non-LTE diagnostics of velocity fields during the gradual phase of a solar flare, , Astronomy and Astrophysics, Feb, Volume 430, p.679-689, (2005) Solar-like Oscillations in α Centauri B, , Astrophysical Journal, Dec, Volume 635, p.1281-1290, (2005) Streamers and adjacent regions observed by UVCS/SOHO: A comparison between different phases of solar activity, , Astronomy and Astrophysics, Feb, Volume 430, p.701-712, (2005) Main Results of the SPIRIT Experiment Onboard the CORONAS-F Satellite, , Solar System Research, Nov, Volume 39, p.442-452, (2005) Helium Line Formation and Abundance in a Solar Active Region, , Astrophysical Journal, Jan, Volume 619, p.604-612, (2005) The Structure of the Lower Transition Region as Inferred from the Hydrogen LYMAN-α Line Radiance, , Chromospheric and Coronal Magnetic Fields, Nov, Volume 596, (2005) The search for complex molecules in comets, , ESA Special Publication, Jan, Volume 577, p.467-468, (2005) Observations of the Sun at Vacuum- Ultraviolet Wavelengths from Space. Part I: Concepts and Instrumentation, , Space Sciences Review, Apr, Volume 111, p.415-480, (2004) Spectroscopic measurement of the plasma electron density and outflow velocity in a polar coronal hole, , Astronomy and Astrophysics, Mar, Volume 416, p.749-758, (2004) Prominence atlas in the SUMER range 800 1250 Å: I. Observations, data reduction and preliminary results, , Solar Physics, Mar, Volume 220, p.61-80, (2004) EIT Observations of the 15 November 1999 Mercury Transit, , Solar Physics, Feb, Volume 219, p.217-230, (2004) Statistical Study of SOHO/SUMER Full-Sun Images, , SOHO 13 Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE, Jan, Volume 547, p.337, (2004) Remote Sensing of Plasma Diagnostics Relating to Coronal Heating, , SOHO 15 Coronal Heating, Dec, Volume 575, p.312, (2004) A Search for Signatures of Preferential Heating by Ion Cyclotron Waves in the Low Corona, , SOHO 13 Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE, Jan, Volume 547, p.391, (2004) Non-LTE Radiative Transfer in Model Prominences. I. Integrated Intensities of He I Triplet Lines, , Astrophysical Journal, Dec, Volume 617, p.614-622, (2004) SUMER, UVCS and LASCO Observations of Small-Scale Ejecta, , SOHO 13 Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE, Jan, Volume 547, p.291, (2004) On the nature of EIT waves, EUV dimmings and their link to CMEs, , Astronomy and Astrophysics, Nov, Volume 427, p.705-716, (2004) | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9311410784721375, "perplexity": 13710.826359391385}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540531917.10/warc/CC-MAIN-20191211131640-20191211155640-00049.warc.gz"} |
http://mathhelpforum.com/algebra/46872-average.html | # Math Help - Average
1. ## Average
The average of 5 results is 46 and that of first 4 is 45.The fifth result is
(a)1
(b)10
(c)12.5
(d)50
2. Hello,
Originally Posted by devi
The average of 5 results is 46 and that of first 4 is 45.The fifth result is
(a)1
(b)10
(c)12.5
(d)50
The average of 5 results is given this way :
$A=\frac{a+b+c+d+e}{5}$, where a,b,c,d,e are the results. In general, you divide the sum of the results by the number of results.
We know that the sum of the first 4 is 45, let's say a+b+c+d=45 and that the average is 46.
$46=\frac{45+e}{5}$
Solve for e...
e+45=46
46-45=e
e=1 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9259002208709717, "perplexity": 1404.6241130245521}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-22/segments/1464053379198.78/warc/CC-MAIN-20160524012939-00089-ip-10-185-217-139.ec2.internal.warc.gz"} |
http://www.cfd-online.com/Forums/main/16437-pressure-enigma-print.html | CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
- Main CFD Forum (http://www.cfd-online.com/Forums/main/)
- - Pressure enigma. (http://www.cfd-online.com/Forums/main/16437-pressure-enigma.html)
Sara March 6, 2009 05:57
Pressure enigma.
Hey,
1. What is the physical interpretation of the pressure in an incompressible fluid?
2. It seems to me that if we are solving the momentum equations explicitly in an incompressible fluid, then we use the pressure-velocity coupling to ensure that we actually are solving the problem implicitly (which sounds correct). Do we actually need the pressure to make this implicit coupling of the velocities in the domain?
otd March 6, 2009 14:18
Re: Pressure enigma.
There's always the option of using the sream function / vorticity formulation (for 1 or 2-d problems with constant viscosity). An extension of that with further manipulation gives a biharmonic equation for the stream function alone (with the same restrictions).
In either case the pressure is eliminated from the calculation - although a pressure field can be retrieved from the stream function solution.
kenn k.q. zhang March 6, 2009 16:30
Re: Pressure enigma.
the disavantages of stream function vorticity include, but not limited to:
6 components in 3d, while 4 components in 3d for velocity-pressure;
vorticty is the derivative of velocity, so it demands more smoothness
kenn k.q. zhang March 6, 2009 17:11
Re: Pressure enigma.
physical interpretation of the pressure in incompressible flows?
pressure is just the pressure, the normal-direction force per area acting on the surfaces you are interested in. nothing fancy for the pressure in incompressible flows, in terms of concept.
however, the propagation of the pressure in the incompressible flows is at an infinite speed. when you want to consider the hydroacoutsics, this is not the case (the speed of sound in water is more than 1000m/s, i don't remember exactly), but otherwise it is. in air, the propagation of pressure is the speed of the sound in air.
that "the pressure progagate at infinite speed" equates a tiny chnage in the density can have a consequence of big change in pressure field. this is called stiffness.
i don't understand your second question, so her i just say something i know.
the role of pressure in incompressible flows is a lagrangian multiplier, which means the pressure demands the velocity field you obtained (with the moving the pressure to the right-hand-side of momentum equations) satify the conservation of mass.
with pressure on the right hand side, where the pressure can be obtained by the approximation from the previous time step, you can get a velocity field. but you can a lot of, as a matter of fact infinite number of, velocity fields. however, such a field must satisfy the continuity equation.
in penalty formulation, you can incorporate the continuity equation into the momentum equation & kind of limintate the pressure. so, you can work out the velocity field alone. penalty formulation reflects the epcicenter of "lagrangian multiplier" literatelly, but it is a bad approach and i surely suggest you not go for it.
in compressible flows, the navier-stokes flows are solved in a mixed formulation, which simply means the most natural approach. unfornulately, at low sonic speed, the stiffness issue occurs and the mixed approaches does very poorly. you may use artificail compressibility or pressure stabilization methods, to try to extend the "mixed formulation"-which is excellent for compressibel flows & compressible elasticity to the incompressible limit. unfortunately, the extension is not successful, either due to implemental complexibity or performance/speed or both.
so, the best category of handling incompressible flows is the splitting. and there are 3 categories for this business:
1. continuous splitting:
you can derive a pressure poisson equation from the momentum and continuity, in a continuous sense; and impose boundary a neumann boundary condition for the pressure poisson; the boundary condition can be derived from application of momentum equation on the normal direction of the boundary. this approach is a little pain at the beginning, due to the boundary condtion; but once you have then ready, it's easy to proceed;
2. discrete splitting:
you can continue the "mixed formulation" or the natural formulation, and get all matrices; then you do some manipulations to get a sub systems for the velocity and a pressure-poisson-like subsystem for the pressure. this apporach share a lot with the mixed formulation, so that it's easy to communicate with traditional compressible slovers. unfortunately, you still need add additonal boundary conditions onto matrices you just got. the reason, after you convert the matrices you just got into subsytems for the velocity and pressure, some information may get inactive, even the conversion is a one-on-one conversion.
there are other types of discrete splitting, such as the one presented in the famous paper published in 1965 on "physics of fluids", in which this technqiue, finite volume method, staggered grid, and MAC free-surface capturing technique can be found (in one single paper -- can we find this kind of highly original papers now?)
3. semi-discrete approach
this is simply the famous "fractional step" or "projection" by Chorin.
I don't the "velocity correction" approach implemented in "Fluent" belongs to which category, such as SIMPLE, SIMPLER, and so on. but the procedures being used by commercial software must be good, which is not necessary a case for those published on journa papers.
kenn k.q. zhang March 6, 2009 17:20
Re: Pressure enigma.
a little calrification:
suppose we onvert system A to system B, in a one-on-one manner.
we might think: since these two systems are equivalent to each other, solving B is the same as soliving A.
unfortunately, this is a wrong idea.
system B indeed equates system A, they contain the same information; however, some information may hide inside the system and simply can't be utilized. in other words, some information stored in system A may become intrinsic in B. as a consequence, we can't solve B and get the correct results.
Sara March 6, 2009 19:31
Re: Pressure enigma.
"pressure is just the pressure, the normal-direction force per area acting on the surfaces you are interested in. nothing fancy for the pressure in incompressible flows, in terms of concept. "
I'm a bit confused here, let me reformulate my first question:
Do we have some pressure acting in the incompressible system other than the dynamic pressure?
ag March 6, 2009 19:46
Re: Pressure enigma.
You have the static pressure, but in terms of the solution of the equations all that is important is the pressure gradient. You can add or subtract a gauge pressure from the flo field and get the same velocity field.
Sara March 6, 2009 19:56
Re: Pressure enigma.
Is it possible to eliminate the pressure term (by say assuming p = 0.5*rho*u²) and do a least-squares fit to the resulting two equations (x-momentum and continuity) in a 1d problem?
Sara March 6, 2009 20:06
Re: Pressure enigma.
Yes. So what is the pressure gradient in an incompressible fluid? I understand that it resolves from the solution of the equations but is there a physical meaning behind it?
Tom March 6, 2009 20:13
Re: Pressure enigma.
In the incompressible equations the pressure (usually referred to as the dynamic pressure to distinguish it from the thermodynamic one) is the internal force required maintain mass conservation (which also prevents cavitation). Basically it describes the coupling between the momentum equation and the continuity equation;i.e. it's the force required to ensure that the velocity evolves in a manner that conserves mass (strictly speaking it's volume in the incompressible equations). If you know about classical mechanics (Lagrange & Hamilton) then in an inviscid fluid the pressure (p) is the "Lagrange multiply" that multiplies the mass-conservation constraint when added to the Lagrangian -variations with respect to p gives the mass conservation equation while variation of the other parameters yields the momentum equations.
Jonas Holdeman March 7, 2009 11:32
Re: Pressure enigma.
The interpretation of the pressure in incompressible flow as a Lagrange multiplier is the result of a particular mathematical analysis of NSE. If the equations are rewritten in the stream function-vorticity form or the stream function form, there is no pressure in the problem. The incompressible velocity field exists and can be computed without regard to the pressure. The incompressibility/mass conservation is being maintained without reference to a pressure. Where is a Lagrange multiplier in this case? If one expands the velocity field in terms of a divergence-free basis, the expansion will always be divergence-free no matter what expansion coefficients are chosen. If the expansion coefficients are chosen to best approximate the solution to the NSE, this solution will be divergence-free without regard to the pressure. The incompressibility condition acts like a conservation law. The "pressure" derived from the velocity field (say by the pressure Poisson equation) is that pressure-like quantity consistent with the flow field. How can we say that the pressure drives incompressible flow if there is no pressure appearing in the governing equation? Incompressibility drives the flow and pressure responds!
Tom March 7, 2009 12:16
Re: Pressure enigma.
"The interpretation of the pressure in incompressible flow as a Lagrange multiplier is the result of a particular mathematical analysis of NSE."
No - it follows from the derivation of the inviscid equations using a Lagrangian. This is also true for compressible flows!
The streamfunction is the mathematical device. It's just a way of hiding the pressure, just like using the vorticity form in the 3D problem.
"The incompressibility condition acts like a conservation law."
No - it behaves as a constraint on the flow. The pressure is gradient is the force required to enforce the constraint. The constraint actually corresponds to the conservation of volume not mass (unless density is constant).
Sara, If you're OK with the (thermodynamics) pressure in the compressible equations then one way of understanding the corresponding term in the incompressible equations is to nondimensionalize the compressible equations and perform a low Mach number asymptotic expansion of the equations. There are many examples of this procedure in papers within the Journal of Fluid mechanics.
Sara March 7, 2009 18:46
Re: Pressure enigma.
Excellent answer Jonas, thank you, this was the essence of my confusion.
Ahmed March 10, 2009 17:03
Re: Pressure enigma.
No No No The confusion,if there is any, is the result of the definition of pressure in the mechanical sense, i.e., the normal component of force ..etc. The Kinetic theory of Gases gives the definition of pressure as the momentum exchange between the molecules or between the molecules and solid boundaries. in other words, it is another thermodynamic property of matter. If you adopt this definition then there will be a pressure whether we treat the flow as incompressible or compressible or whatever. It is a property of matter. Good Luck.
otd March 10, 2009 19:51
Re: Pressure enigma.
But the original question was about INCOMPRESSIBLE flow.
kenn k.q. zhang March 11, 2009 21:22
Re: Pressure enigma.
i suggest you not to try these kinds of approaches.
in fundamenatal and long-standing things, it's better to use something popular; once you reach to the front of the research field, try hard something unconventional
jwm March 16, 2009 09:29
The original question was about the PHYSICAL interpretation of pressure, so forget Lagrange multipliers.
Suppose you have a fluid completely at rest. The molecules are moving at high speed with random thermal motion. The molecules collide either with a real surface, or with the molecules on the other side of an imaginary surface. The average of these forces of collision give a normal force (the tangential forces cancel statistically) called the pressure.
Now, if there is a velocity gradient the tangential forces do not quite cancel and a normal and a shear force are exerted on the surface. The normal force is called pressure and the tangential force is called viscosity.
Incompressible or compressible - same thing
Jonas Holdeman March 16, 2009 17:13
No, John M, the question was
"1. What is the physical interpretation of the pressure in an incompressible fluid?"
The key word here is "incompressible." We must distinguish between "incompressible flow" (a property of real fluids) and an "incompressible fluid" (which is an idealized concept). The incompressible fluid provides a model for incompressible flow. Being a concept, we do not have access to an incompressible fluid to experiment with and experimentally infer its properties. The closest thing in nature to an incompressible fluid might be the core of a neutron star, but we don't have access to that. So we must be careful of applying intuition, and examine the fluid from its mathematical description.
There are (at least) two time (and spacial) scales associated with a real fluid, one associated with the speed of the fluid and one associated with the speed of sound c(pressure variations) in the fluid. We may charactize the relation between these two by the Mach number . For very small Mach number the nonstationary equations become stiff and computations become difficult. Taking the limit as eliminates one of these scales giving the incompressible NSE and better-conditioned computations, but at a price.
If we expand the density , pressure and velocity in powers of and collect terms with the same power, we find that to lowest order, the pressure appearing in the momentum equation (which is now the incompressible NSE) is the coefficient of , two orders higher than the density or velocity. Thus an important part of what was the physical pressure is missing in the INSE momentum equation. So we should not be surprised that the pressure in the momentum equation does not behave quite like the physical pressure. Since leading pieces (which lead via energy conservation to the continuity equation) are missing, this cannot be a thermodynamic pressure.
So what is the interpretation of this pressure? I can say a lot about it, but I am not entirely comfortable saying what it is in physical terms.
Ford Prefect March 17, 2009 06:11
Quote:
Originally Posted by Jonas Holdeman (Post 209664) No, John M, the question was "1. What is the physical interpretation of the pressure in an incompressible fluid?" The key word here is "incompressible." We must distinguish between "incompressible flow" (a property of real fluids) and an "incompressible fluid" (which is an idealized concept). The incompressible fluid provides a model for incompressible flow. Being a concept, we do not have access to an incompressible fluid to experiment with and experimentally infer its properties. The closest thing in nature to an incompressible fluid might be the core of a neutron star, but we don't have access to that. So we must be careful of applying intuition, and examine the fluid from its mathematical description. There are (at least) two time (and spacial) scales associated with a real fluid, one associated with the speed of the fluid and one associated with the speed of sound c(pressure variations) in the fluid. We may charactize the relation between these two by the Mach number . For very small Mach number the nonstationary equations become stiff and computations become difficult. Taking the limit as eliminates one of these scales giving the incompressible NSE and better-conditioned computations, but at a price. If we expand the density , pressure and velocity in powers of and collect terms with the same power, we find that to lowest order, the pressure appearing in the momentum equation (which is now the incompressible NSE) is the coefficient of , two orders higher than the density or velocity. Thus an important part of what was the physical pressure is missing in the INSE momentum equation. So we should not be surprised that the pressure in the momentum equation does not behave quite like the physical pressure. Since leading pieces (which lead via energy conservation to the continuity equation) are missing, this cannot be a thermodynamic pressure. So what is the interpretation of this pressure? I can say a lot about it, but I am not entirely comfortable saying what it is in physical terms.
Interesting discussion. So where does this put compressible flows, seeing that we use the thermodynamic pressure in the cNSE, which magnitude depends on effects we do not model? Is it one part "physical reasoning" and one part numerical?
Ahmed March 17, 2009 22:49
Quote:
Originally Posted by Jonas Holdeman (Post 209664) No, John M, the question was "1. What is the physical interpretation of the pressure in an incompressible fluid?" The key word here is "incompressible." We must distinguish between "incompressible flow" (a property of real fluids) and an "incompressible fluid" (which is an idealized concept). The incompressible fluid provides a model for incompressible flow. Being a concept, we do not have access to an incompressible fluid to experiment with and experimentally infer its properties. The closest thing in nature to an incompressible fluid might be the core of a neutron star, but we don't have access to that. So we must be careful of applying intuition, and examine the fluid from its mathematical description. There are (at least) two time (and spacial) scales associated with a real fluid, one associated with the speed of the fluid and one associated with the speed of sound c(pressure variations) in the fluid. We may charactize the relation between these two by the Mach number . For very small Mach number the nonstationary equations become stiff and computations become difficult. Taking the limit as eliminates one of these scales giving the incompressible NSE and better-conditioned computations, but at a price. If we expand the density , pressure and velocity in powers of and collect terms with the same power, we find that to lowest order, the pressure appearing in the momentum equation (which is now the incompressible NSE) is the coefficient of , two orders higher than the density or velocity. Thus an important part of what was the physical pressure is missing in the INSE momentum equation. So we should not be surprised that the pressure in the momentum equation does not behave quite like the physical pressure. Since leading pieces (which lead via energy conservation to the continuity equation) are missing, this cannot be a thermodynamic pressure. So what is the interpretation of this pressure? I can say a lot about it, but I am not entirely comfortable saying what it is in physical terms.
This is a very old discussion that dates back to the 19th centuray and when the Navier Stokes equation was written.
But it would be of benfit if we recall the origin of the incompressible flow definition, so here it is, Engineers have found that in a process where changes in the density of a fluid are less than 3% can be neglected and hence we can treat the flow as a constant density fluid/flow. The result of this engineering criterion is that the divergence is Zero and hence the simplified Navier Stokes equation.
In short, when that criterion is adopted, we say that density changes are neglected and nothing more than that. (bear in mind that density changes may be the result of pressure or temperature changes or both) but for engineering design purposes we neglect that change in the magnitude of the density but not in the causes of that change.
Hope that will help
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https://byjus.com/jee/jee-main-2019-question-paper-physics-april/ | # JEE Main 2019 April Physics Paper with Solutions
JEE is an examination conducted for admission into various institutions across the country. The questions asked in the examination are based on Class 11 and Class 12 syllabus. The JEE aspirants can refer to this page to find the answers for all the questions asked in JEE 2019 April Physics paper. These answers are provided by the subject experts at BYJU’S.
### April Paper - Physics
1. A capacitor of capacitance C = 15 pF is charged with voltage V = 500 V. The electric field inside the capacitor with dielectric is 106 V/m and the area of the plate is 10– 4 m2, then the dielectric constant of the medium is: (
$${{\varepsilon }_{0}}=8.85\times {{10}^{-12}}$$
in SI units)
1. a.12.47
2. b.8.47
3. c.10.85
4. d.14.85
Solution:
1. C = 15PF
V = 500V
E = 106 V/m
A = 10– 4 m2
$$C=\frac{k{{\varepsilon }_{0}}A}{d}$$
$$d=\frac{k{{\varepsilon }_{0}}A}{C}$$
E = V/d
$$E= \frac{500 C}{k{{\varepsilon }_{0}}A}$$
$$K=\frac{Vc}{A{{\varepsilon }_{0}}E}=\frac{500\times 15\times {{10}^{-12}}}{{{10}^{-4}}\times {{10}^{6}}\times 8.85\times {{10}^{-12}}}$$
= 8.47
2. The electric field of EM wave is 6 volt/m. The magnetic field associated with the wave if the wave is propagating in the +x direction and electric field along y-axis is:
1. a.
$${{10}^{-8}}T\hat{K}$$
2. b.
$$2\times {{10}^{-8}}T\hat{K}$$
3. c.
$$3\times {{10}^{-8}}T\hat{K}$$
4. d.
$$4\times {{10}^{-8}}T\hat{K}$$
Solution:
1. E = BC
$$B =\frac{E}{C}=\frac{6}{3\times {{10}^{8}}}=2\times {{10}^{-8}}T(along\,z-axis)$$
3. An electron of H-atom de-exits from energy level m1 = 2 to h2 = 1 and the emitted photon is incident on He+ ion in ground state and first ox cited states which of following transition is possible.
1. a. n = 1 to n = 4
2. b. n = 2 to n = 4
3. c. n = 2 to n = 3
4. d. n = 1 to n = 4
Solution:
1. $${{E}_{H}}=13.6\left\{ \frac{1}{{{1}^{2}}}-\frac{1}{{{2}^{2}}} \right\}=10.2\,ev$$
$${{E}_{H}}=13.6{{(2)}^{2}}\left\{ \frac{1}{{{2}^{2}}}-\frac{1}{{{n}^{2}}} \right\}$$
substituting options n = 4
4. The switch is closed at t = 0. The time after which the rate of dissipation of energy in the resistor is equal to rate at which energy is being store in the inductor is:
1. a.
$$\ell n2$$
2. b.
$${}^{1}/{}_{2}\ell n2$$
3. c.
$${}^{1}/{}_{4}\ell n2$$
4. d.
$$2\ell n2$$
Solution:
1. $$i=\frac{E}{R}(1-e^{-\frac{Rt}{L}})$$
$$\frac{di}{dt}=\frac{E}{L}e^{-\frac{t}{\tau }}$$
,where
$$\tau =\frac{L}{R}$$
$$i^{2}R=(L\frac{di}{dt})$$
$$\frac{E}{R}R(1-e^{-\frac{t}{\tau }})=L \frac{E}{L}e^-{\frac{t}{\tau }}$$
1 = 2e-e/ τ
ln2 = t/ τ
t = τ ln2
5. Two identical containers of same emissivity containing liquids A & B at same temperature of 60°c initially and densities PA and PB respectively. Where, PA< PB. Which plot best represents the temperature variation of both with time? Given
$$\left( \begin{matrix} {{S}_{A}}=100\frac{J}{kg-{{k}^{1}}} \\ {{S}_{B}}=2000\frac{J}{kg-k} \\ \end{matrix} \right)$$
.
Solution:
1. $$\frac{d\theta }{dt}=\frac{\theta eA\left( T_{0}^{m}-T_{0}^{A} \right)}{ms}$$
$$\frac{d\theta }{dt}\alpha \frac{1}{ms}$$
6. The system of 2 rods shown in fig is vibrating at the same frequency and forming a standing wave. The ratio of the number of antinodes in the two rods if radius of rod B is twice the radius of A is:
1. a.1
2. b.2
3. c.3
4. d.4
Solution:
1. $$f_{1} = \frac{n}{2l}\sqrt{\frac{T}{\rho A}}f_{2} = \frac{m}{2l}\sqrt{\frac{T}{\rho 4A}}$$
Given f1 = f2
$$\frac{f_{1}}{f_{2}} = \frac{n}{m}\times 2$$
$$\frac{n}{m}\times 2$$
7. At the given instant the four particles having masses and acceleration as shown in the fig lie at vertices of a square. Acceleration of the mass of the system is:
1. a.
$$\frac{1}{5}\left( \hat{i}+\hat{j} \right)$$
2. b.
$$\frac{1}{5}\left( \hat{j}-\hat{i} \right)$$
3. c.
$$\frac{1}{5}\left( \hat{i}-\hat{j} \right)$$
4. d.
$$\frac{1}{5}\left( \hat{i}+\hat{j} \right)$$
Solution:
1. $${{a}_{am}}=\frac{{{m}_{1}}{{a}_{1}}+{{m}_{2}}{{a}_{2}}+{{m}_{3}}{{a}_{3}}+{{m}_{4}}{{a}_{4}}}{{{m}_{1}}+{{m}_{2}}+{{m}_{3}}+{{m}_{4}}}$$
$$=\frac{m\left( -a\hat{i} \right)+2m\left( a\hat{j} \right)+3m\left( a\hat{i} \right)+4m\left( -a\hat{j} \right)}{m+2m+3m+4m}$$
=
$$\frac{2i-2\hat{j}}{10}=\left( \frac{{\hat{i}}}{5}-\frac{{\hat{j}}}{5} \right)$$
8. In YDSE ratio of Amplitude of wave is 1: 3. The ratio of I max: I min is:
1. a. 1: 4
2. b. 4: 1
3. c. 1: 1
4. d. 1: 9
Solution:
1. $$\frac{{{I}_{max}}}{{{I}_{min}}}={{\left( \frac{{{A}_{1}}+3{{A}_{1}}}{{{A}_{1}}-3{{A}_{1}}} \right)}^{2}}=\frac{4}{1}$$
9. Two particles are moving perpendicular to each other with de-Broglie wave length λ1 and λ2 if they collide and stick then the de-Broglie wave length of system after collision is:
1. a.
$$\lambda =\frac{{{\lambda }_{1}}{{\lambda }_{2}}}{\sqrt{\lambda _{1}^{2}+\lambda _{2}^{2}}}$$
2. b.
$$\lambda =\frac{{{\lambda }_{1}}}{\sqrt{\lambda _{1}^{2}+\lambda _{2}^{2}}}$$
3. c.
$$\frac{\sqrt{\lambda _{1}^{2}+\lambda _{2}^{2}}}{{{\lambda }_{2}}}$$
4. d.
$$\lambda =\frac{{{\lambda }_{1}}{{\lambda }_{2}}}{\sqrt{{{\lambda }_{1}}+{{\lambda }_{2}}}}$$
Solution:
1. Pi + Pj = P
$$\frac{h}{{{\lambda }_{1}}}\hat{1}+\frac{h}{{{\lambda }_{2}}}\hat{j}=\frac{h}{\lambda }$$
$$\frac{1}{\lambda }=\sqrt{\frac{1}{{{\lambda }_{1}}}+\frac{1}{{{\lambda }_{2}}}}$$
$$\lambda =\frac{{{\lambda }_{1}}{{\lambda }_{2}}}{\sqrt{\lambda _{1}^{2}+\lambda _{2}^{2}}}$$
10. Ship moving with velocity
$${{\vec{V}}_{1}}=30\hat{i}+50\hat{j}$$
from position (0, 0) and ship B moving with velocity
$$\overrightarrow{{{V}_{2}}}=-10\hat{i}$$
from position (80, 150). The time for minimum separation is
1. a. 2.6
2. b. 2.2
3. c. 2.4
4. d. None
Solution:
1. $${{V}_{1}}=30\hat{i}+50\hat{j}$$
$$r=-80\hat{i}-150\hat{j}$$
$${{V}_{2}}=-10\hat{i}$$
$$\vec{v} = 40i + 50j$$
Component of V1 along r is
$$\frac{V.r}{{{V}^{2}}}=2.6$$
11. A carbon resistance with color bard is 200 Ω. If red bard is replaced by green bard then the new resistance is
1. a. 500 Ω
2. b. 300 Ω
3. c. 400 Ω
4. d. 100 Ω
Solution:
1. Red 2
Green 5
New resistance 500 Ω
12. Dimension of
$$\sqrt{\frac{{{\varepsilon }_{0}}}{{{\mu }_{0}}}}$$
are
1. a.
$$\left[ M{{L}^{2}}{{T}^{-3}}{{A}^{-2}} \right]$$
2. b.
$$\left[ {{M}^{-1}}{{L}^{-2}}{{T}^{3}}{{A}^{2}} \right]$$
3. c.
$$\left[ {{M}^{2}}{{L}^{2}}{{T}^{-3}}{{A}^{-2}} \right]$$
4. d.
$$\left[ {{M}^{-1}}{{L}^{2}}{{T}^{3}}{{A}^{2}} \right]$$
Solution:
1. $$\sqrt{\frac{\varepsilon {}_{0}}{{{\mu }_{0}}}}=\sqrt{\frac{{{\varepsilon }_{0}}{{\varepsilon }_{0}}}{{{\mu }_{0}}{{\varepsilon }_{0}}}}\Rightarrow {{\varepsilon }_{0}}.C$$
$$\frac{Co{{l}^{2}}}{N{{m}^{2}}}(m/s)=\frac{{{I}^{2}}{{T}^{2}}\not{L}{{T}^{-1}}}{M\not{L}{{T}^{-2}}{{L}^{2}}}$$
$$=\left[ {{M}^{-1}}{{L}^{-2}}{{T}^{3}}{{A}^{2}} \right]$$
13. A electric circuit is shown in figure. The potential different between the points A & B is:
1. a.
$$\frac{10}{3}$$
2. b.
$$\frac{20}{3}$$
3. c.
$$\frac{5}{3}$$
4. d.
$$\frac{7}{3}$$
Solution:
1. Using nodal method
$$\frac{{{V}_{A}}-2}{2\Omega }+\frac{{{V}_{A}}-4}{2}+\frac{{{V}_{A}}-4}{2}=0$$
$$\frac{V^{A}}{2}-1+\frac{V^{A}}{2}-2+\frac{V^{A}}{2}-2=0$$
$$V^{A}\left( {}^{1}/{}_{2}+{}^{1}/{}_{2}+{}^{1}/{}_{2} \right)=5$$
$${{V}_{A}}=\left( \frac{3}{2} \right)=5$$
$${{V}_{A}}\frac{10}{3}$$
14. 10 particles each of mass 10-26 kg are striking perpendicularly on a wall of area 1 m2 with speed 104 m/s in 1 sec. The pressure on the wall if collision are perfectly elastic is:
1. a. 2 N/m2
2. b. 4 N/m2
3. c. 6 N/m2
4. d. 8 N/m2
Solution:
1. Collision Frequency = 1022
ΔP per particle = mV2
$$F=\frac{\Delta P}{1\sec }={{10}^{22}}\times mv$$
=
$${{10}^{22}}\times {{10}^{-26}}\times 2\times {{10}^{4}}=2$$
$$P={}^{F}/{}_{A}={}^{2}/{}_{1}=2$$
N/m2
15. An elastic string of Length 42 cm and cross section area 10–4 m2 is attached between two pegs at distance 6mm as shown in the figure. A particle of mass m is kept at mid point of string stretched as shown in figure by 20 cm and released. As the string attains natural Length, the particle attains a speed of 20 m/s. Then young modulus Y of string is of order.
1. a. 108
2. b. 1012
3. c. 106
4. d. 104
Solution:
1. Elastic stream energy × volume = kinetic energy
$$Vol\times \frac{1}{2}stress\,\times strain={}^{1}/{}_{2}m{{v}^{2}}$$
$$Vol\times \frac{1}{2}\frac{stress}{strain}.strai{{n}^{2}}={}^{1}/{}_{2}m{{v}^{2}}$$
$$=\,{}^{1}/{}_{2}y{{(strain)}^{2}}vol={}^{1}/{}_{2}m{{v}^{2}}$$
$$Y=\frac{m\times {{v}^{2}}}{AL{{\left( \frac{\Delta \ell }{\ell } \right)}^{2}}}$$
Y = [(0.05 x400 x0.42)/(0.2)2 x 10-4]
Y = 2.1 x 106 N/m2
16. The density of a circular disc is given as σ =
$${{p}_{0}}X$$
where ‘X’ is the distance from the centre. Its moment of interia about an axis perpendicular to interia about an axis perpendicular to its plane and passing through its edge is:
1. a.
$$\frac{15}{16}{{P}_{0}}\pi {{R}^{5}}$$
2. b.
$$\frac{16}{15}{{P}_{0}}\pi {{R}^{5}}$$
3. c.
$$\frac{6}{5}{{P}_{0}}\pi {{R}^{5}}$$
4. d.
$$\frac{5}{6}{{P}_{0}}\pi {{R}^{5}}$$
Solution:
1. Using parallel axis
dI = dmx2 + d MR2
$$dI=\int{{{P}_{0}}2\pi {{x}^{2}}dx.{{x}^{2}}+}\int{{{P}_{0}}}2\pi {{x}^{2}}dx{{R}^{2}}$$
$$=\frac{{{P}_{0}}2\pi R^{5}}{5}+\frac{{{P}_{0}}2\pi {{R}^{5}}}{3}=\frac{16{{P}_{0}}\pi {{R}^{5}}}{15}$$
17. The circuit shown in the figure. Determine the current through Zener diode. (Given: Zener diode break down. Voltage V2 = 5.6 V)
1. a. 7 mA
2. b. 17 mA
3. c. 10 mA
4. d. 15 mA
Solution:
1. I1 = I2 + Iz
$$\frac{3.4}{200}={{I}_{2}}+\frac{5.6}{800}$$
I2 = 10 mA.
18. A small sphere of mass m = 2gm having charge Q = 5 mc is suspended using an insulated string as shown in figure. The angle Ɵ made by the sphere with vertical if it is placed in an electric field of magnitude 2000 y/m towards right is
1. a. tan–1 (5)
2. b. tan–1 (0.5)
3. c. tan–1 (2)
4. d. tan–1 (0.2)
Solution:
1. F = mg tan Ɵ
$$\tan \theta =\frac{F}{mg}$$
$$\(\theta = \tan ^{-1}\left( \frac{QE}{mg} \right)$$
$$={{\tan }^{-1}}\left( \frac{5\times {{10}^{-6}}\times 2000}{7\times {{10}^{-3}}\times 10} \right)$$
$$={{\tan }^{-1}}\left( \frac{1}{2} \right)={{\tan }^{-1}}(0.5)$$
19. A circular loop of radius r having N number of turns carries current I is placed in a uniform magnetic field
$$\overrightarrow{B}$$
parallel to the plane of the loop. The torque on the loop is
1. a.
$$N\ell \pi {{r}^{2}}B$$
2. b.
$${{N}^{2}}\ell \pi {{r}^{2}}B$$
3. c.
$$N{{\ell }^{2}}\pi {{r}^{2}}B$$
4. d.
$$N\ell \pi {{r}^{2}}{{B}^{2}}$$
Solution:
1. τ = M × B
= MB sin Ɵ
= NI πr2 ×B(1)
= NI πr2B
20. A conducting sphere is enclosed by a hollow conducting shell. Initially the inner sphere has a charge Q. While the outer one is un charged. The potential difference between the two spherical surface is found to be V. Later on the outer shell is given a charge – 4Q. The new potential difference between the two surface.
1. a. 1V
2. b. – IV
3. c. – 2V
4. d. 2V
Solution:
1. $${{V}_{A}}=\frac{KQ}{a}+\frac{K(-Q+Q)}{b}$$
$${{V}_{B}}=\frac{KQ}{b}+\frac{K(-Q+Q)}{b}$$
$$\Delta V=KQ\left( {}^{1}/{}_{a}-{}^{1}/{}_{b} \right)$$
$${{V}_{A}}=\frac{KQ}{a}-\frac{K4Q}{b}$$
$${{V}_{B}}=\frac{KQ}{b}-\frac{K4Q}{b}$$
ΔV = V
21. Four particle each of mass m are undergoing circular motion under the influence of action of their mutual gravitational interaction while being at the vertices of a square of side a. Their speeds are
1. a.
$$\sqrt{\frac{2GM}{a}}$$
2. b.
$$1.16\sqrt{\frac{GM}{a}}$$
3. c.
$$1.5\sqrt{\frac{2M}{a}}$$
4. d.
$$\sqrt{\frac{GM}{a}}$$
Solution:
1. Gravitation Force = mv2/r
r =
$$\sqrt{a^{2}-(\frac{a}{\sqrt{2}})^{2}}=\frac{a}{\sqrt{2}}$$
$$\frac{G{{m}^{2}}}{a^{2}}cos45^{0}+\frac{G{{m}^{2}}}{(\sqrt{2}a)^{2}}+\frac{G{{m}^{2}}}{a^{2}}cos45^{0}=mv^{2}/(a/\sqrt{2})$$
$$\frac{G{{m}^{2}}}{a^{2}}[\frac{1}{\sqrt{2}}+\frac{1}{2}+\frac{1}{\sqrt{2}}]=(mv^{2}\sqrt{2})/a$$
$$v^{2}=1.35(\frac{GM}{a})$$
$$1.16\sqrt{\frac{GM}{a}}$$
22. A converging lens of focal length 20 cm is placed between an object & a concave mirror of focal mirror of focal length 10 cm as shown in figure. The final image is
1. a. Coinciding with object, enlarged, Inverted real
2. b. Coinciding with object, same size, erect, real
3. c. Coinciding with object, same size, Inverted, Vertical
4. d. Coinciding with object, same size, Inverted, real
Solution:
1. Coinciding with object, same size, Inverted, real
23. A conducting slider of resistance R (10 Ω) mass 50 g & length 10 cm is kept on a U – shaped frame as shown in figure. There is uniform magnetic field (B = 0.1T) perpendicular to plane of frame. These slider is attached to a spring (K = 0.5 N/m). It is displaced by AƟ& released time is which amplitude become A /e is
1. a. 9000 s
2. b. 10000 s
3. c. 12000 s
4. d. 15000 s
Solution:
1. $$-Kx-i\ell B=m\frac{{{d}^{2}}x}{d{{\ell }^{2}}}$$
$$-Kx-\frac{{{B}^{2}}{{\ell }^{2}}}{R}\frac{dx}{d\ell }-m\frac{{{d}^{2}}x}{d{{\ell }^{2}}}=0$$
Comparing with
$$-Kx-b\frac{dx}{dt}-m\frac{{{d}^{2}}x}{d{{\ell }^{2}}}=0$$
&
A = A0e(-b/2m)t
$$\frac{{{B}^{2}}{{\ell }^{2}}}{R.2m}t=1$$
$$t=\frac{2mR}{{{B}^{2}}{{\ell }^{2}}}=10,000s$$
24. An A.C source of voltage V = 220 sin (100 πt) volts is connected with R = 50 Ω. The time interval in which the current goes from its peak value to half of the peak value is
1. a.
$$\frac{1}{400}\sec$$
2. b.
$$\frac{1}{50}\sec$$
3. c.
$$\frac{1}{300}\sec$$
4. d.
$$\frac{1}{200}\sec$$
Solution:
1. For oscillation to go from max to half is T / 6
$$=\frac{1}{50\times 6}=\frac{1}{300}\sec$$
25. Force displacement graph of a particle starting from rest is given in the figure shown. The kinetic energy of particle at x = 3m is
1. a. 6.5 J
2. b. 7.5 J
3. c. 6 J
4. d. 5 J
Solution:
1. Area under graph is work done
$$w=2\times 2+\frac{1}{2}\times (2+3)\times 1$$
= 6.5J
26. Find out the no of reflection after which light ray will exit from (Given sin 40° = 0.64)
1. a. 130000
2. b. 57803
3. c. 140000
4. d. 150000
Solution:
1. $$x=\frac{20mm}{\tan r}=20\sqrt{3}m$$
For one reflection
$$nx=20\sqrt{3}m=2m$$
∴
$$n=\frac{2}{20\sqrt{3}\times {{10}^{-6}}m}$$
= 57803
27. A block of mass 4 kg is suspended from the ceiling with the help of a steel wire off radius 2 mm and negligible mass. Find the stress in the wire (g = π2)
1. a. 4 × 106
2. b. 3 × 105
3. c. 3.14 × 106
4. d. 2 × 106
Solution:
1. $$stress=\frac{F}{A}=\frac{mg}{\pi {{r}^{2}}}$$
$$\frac{m{{\pi }^{\not{2}}}}{\not{\Pi}{{r}^{^{2}}}}=\frac{4\pi }{{{r}^{2}}}$$
= 3.14 × 106 N/m2
28. A liquid of coefficient of viscosity
$$\eta =1$$
poise is flowing in a pipe of radius 3 cm on such that the rate of volume flow is 1000 / min. determine the Reynolds numbers.
1. a. 3536
2. b. 3500
3. c. 3400
4. d. 3600
Solution:
1. $$\eta$$
= 1 poise
r = 3 cm
$$\frac{dv}{dt}=1000\,{}^{\ell }/{}_{\min }$$
$$Reynolds Number {R}_{e}=\frac{\rho vD}{\eta }$$
$$=\frac{1000}{0.1}\times \frac{1}{60\pi {{r}^{2}}}2r$$
= 3536 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7288681268692017, "perplexity": 2622.4215773797055}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710953.78/warc/CC-MAIN-20221204004054-20221204034054-00097.warc.gz"} |
http://perimeterinstitute.ca/video-library?title=&page=701&qt-videos=0 | # Video Library
Since 2002 Perimeter Institute has been recording seminars, conference talks, public outreach events such as talks from top scientists using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities.
Recordings of events in these areas are all available and On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA)PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
Accessibly by anyone with internet, Perimeter aims to share the power and wonder of science with this free library.
## Physics Education Research: Helping Students Become Better Scientists
Thursday Jul 21, 2011
Speaker(s):
Physics Education Research (PER) is a blossoming subfield of physics that is changing the way students become physicists. Our research involves the transformation of the lab portion of a first-year enriched physics course through the implementation of “invention activities:” discovery-learning activities that ask students to “invent” a solution to a problem before being taught the expert solution.
## Exploring the Viscoelastic Properties of PAA Phantoms
Thursday Jul 21, 2011
Speaker(s):
A gel that has similar thermodynamic properties to human tissue is necessary for determining the safety of implanted medical devices during magnetic resonance imaging (MRI). One particular gel recommended by the ASTM standard (F218209) is the polyacrylic acid (PAA) phantom. In this work, PAA mixtures were characterized by measuring viscosity (as a function of shear rate), electrical conductivity, thermal conductivity, and elastic and viscous moduli (as a function of frequency).
## Crystallinity, Magnetic and Electrical Properties of Doped Perovskite-Oxid
Thursday Jul 21, 2011
Speaker(s):
Sepiedeh Pirasteh
## QCD Confinement at Finite Chemical Potential and the Gravity Dual
Thursday Jul 21, 2011
Speaker(s):
## Testing the Nature of Black Hole Candidates
Thursday Jul 21, 2011
Speaker(s):
Today there is robust observational evidence of dark and compact objects in X-ray binary systems with a mass of 5-20 $M_\odot$ and in galactic nuclei with a mass of $10^5 - 10^9$ $M_\odot$. The conjecture is that all these objects are the Kerr black holes predicted by General Relativity, as they cannot be explained otherwise without introducing new physics. However, there are no directs observational evidences. In this talk, I discuss how the Kerr black hole hypothesis can be tested with present and future X-ray data and the current constraints on the nature of this objects.
Collection/Series:
Scientific Areas:
## Spectroscopic Study of Atmospheric Trace Gases
Thursday Jul 21, 2011
Speaker(s):
Molecular spectroscopy offers the tools and instrumentation needed to unveil the structure and characteristics of molecules that are found within planetary atmospheres. In order to do this we examine the frequencies of light that these molecules either absorb or emit. It is the fine structure of these absorption or emission features that give us information about their physical state.. In our lab we use a near-infrared source to probe various molecules and examine absorption features and their dependency on both temperature and pressure.
## Using Antimatter to Aid in the Design of Safer more Efficient Nuclear Power Plants
Thursday Jul 21, 2011
Speaker(s):
We are doing research on the chemical reaction of the hydrogen atom with water under sub- and supercritical conditions. Supercritical water is water above the critical point (373.9 C and 220.6 bar). This reaction is one of the most important reactions in the next generation of nuclear reactors called Gen IV, where supercritical water will be used as a coolant. We have been studying this reaction by the SR experimental technique.
## Measurement of the Radiopurity of Acrylic for the DEAP-3600 Dark Matter Experiment
Thursday Jul 21, 2011
Speaker(s):
The DEAP-3600 single-phase liquid argon detector at SNOLAB will increase the sensitivity to spin-independent WIMP-nucleon scatters by two orders of magnitude, allowing for the possibility of dark matter particle detection. The spherical detector will contain 3600 kg of liquid argon in an 85 cm radius acrylic vessel surrounded by 255 photomultiplier tubes (PMTs). After a collision between a WIMP and an Ar-40 nucleus, the scintillation light from the recoiling nucleus will be collected by PMTs. The separation of background events from WIMP events is critical.
## Measurement of the Pion Branching Ratio at TRIUMF : A Sensitive Probe in the Search for New Physics
Thursday Jul 21, 2011
Speaker(s):
Study of rare decays is an important approach for exploring physics beyond the Standard Model (SM). The branching ratio of the helicity suppressed p ? e? decay, is one of the most accurately calculated decay process involving hadrons and has so far provided the most stringent test of the hypothesis of electron-muon universality in weak interactions.
## Scattering Kernel for Aperture Modulated Total Body Irradiation
Thursday Jul 21, 2011
Speaker(s):
The goal of Total Body Irradiation (TBI) is to deliver a uniform dose of radiation to the entire body, to destroy cancerous cells. Since the human body is not uniform in either density or thickness, it is difficult to deliver a uniform dose. A novel, Aperture Modulated, Total Body Irradiation (AMTBI) technique was introduced by researchers at the Tom Baker Cancer Centre to address this problem. The AMTBI technique reduces the dose deviation along the midline in the longitudinal direction to less than 5%, as compared to 15% with conventional TBI.
## Next Public Lecture
### CLIFFORD JOHNSON: UNIVERSITY OF SOUTHERN CALIFORNIA
Wednesday Feb 06, 2019
## LECTURES ON-DEMAND
### Jocelyn Bell Burnell: University of Oxford
Speaker: Jocelyn Bell Burnell | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5995410084724426, "perplexity": 2504.2695913707207}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583792338.50/warc/CC-MAIN-20190121111139-20190121133139-00472.warc.gz"} |
https://www.mathportal.org/math-tests/algebra2-tests/tests-in-complex-numbers.php?testNo=2 | Math Calculators, Lessons and Formulas
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• Complex Numbers
• Tests in Complex Numbers
• Adding and subtracting complex numbers
# Adding and subtracting complex numbers
ans:
syntax error
C
DEL
ANS
±
(
)
÷
×
7
8
9
4
5
6
+
1
2
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=
0
.
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• Question 1: 1 pts Add: $(2 + 3i) + (3-4i)$
$5+7i$ $5-7i$ $5+i$ $5-i$
• Question 2: 1 pts Add: $(-5-11i) + (4-6i)$
$1-5i$ $1-17i$ $-1-17i$ $-1-5i$
• Question 3: 1 pts Subtract: $(5-3i) - (3-2i)$
$2-i$ $2+i$ $2-5i$ $2+5i$
• Question 4: 1 pts Subtract: $(-1-i) - (3-5i)$
$4-4i$ $-4+4i$ $-2+4i$ $2-4i$
• Question 5: 2 pts Simplify expression $2(1-i) - 3(3-5i)$
$-11+17i$ $-7-13i$ $-7+13i$ $11-17i$
• Question 6: 2 pts Simplify expression $-3(5-2i) - 4(2-i)$
$-23+10i$ $-23-10i$ $17+10i$ $17-10i$
• Question 7: 2 pts Which point represents the sum of complex numbers $z1$ and $z2$.
A B C D
• Question 8: 2 pts Which point represents the sum of complex numbers $z1$ and $z2$.
A B C D
• Question 9: 2 pts Which point represents the difference of complex numbers $z1$ and $z2$.
A B C D
• Question 10: 2 pts Which point represents the difference of complex numbers $z1$ and $z2$.
A B C D | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6818166375160217, "perplexity": 1329.579434651061}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296948673.1/warc/CC-MAIN-20230327154814-20230327184814-00496.warc.gz"} |
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