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Judicial Watch came to public attention after filing eighteen lawsuits against the administration of Democratic U.S. President Bill Clinton and other figures in the Clinton administration. An early lawsuit was filed by Judicial Watch on behalf of the Western Center for Journalism (WCJ) in 1998. The lawsuit alleged a retaliatory audit by the Internal Revenue Service (IRS). The WCJ was investigating the death of Clinton deputy White House counsel Vince Foster at the time. The organization received considerable financial support from prominent Clinton critics, including $7.74 million from conservative billionaire Richard Mellon Scaife. This led Clinton administration officials to accuse Judicial Watch of "abusing the judicial system for partisan ends". Bush administration
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In July 2003 Judicial Watch joined the environmental organization Sierra Club in suing the George W. Bush administration for access to minutes of Vice President Dick Cheney's Energy Task Force. Judicial Watch was involved in a similar legal dispute with Vice President Dick Cheney in 2002 when the group filed a shareholder lawsuit against Halliburton. The lawsuit, which accused Halliburton of accounting fraud, alleged that "when Mr. Cheney was chief executive of Halliburton, he and other directors inflated revenue reports, boosting Halliburton's share price." As reported by the Wall Street Journal the court filing claims the oil-field-services concern overstated revenue by a total of $445 million from 1999 through the end of 2001. Obama administration Judicial Watch filed over twenty FOIA lawsuits involving the Secretary of State Hillary Clinton's emails.
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A federal judge ruled on February 23, 2016, that top aides to Hillary Clinton could be questioned under oath by Judicial Watch about her use of a private email server as secretary of state. District Court Judge Emmet G. Sullivan granted Judicial Watch's motion for discovery into whether the State Department and former Secretary of State Hillary Clinton deliberately thwarted the Freedom of Information Act by using a private email server to obscure her communications from public records requests. In March 2020, federal district court judge Royce Lamberth ruled that Clinton must provide a deposition. A three-judge panel of the DC Circuit Court of Appeals unanimously overturned Lamberth's ruling the following August. The full DC Circuit Court unanimously declined to hear an appeal in October, allowing the panel decision to stand. In March 2021, the United States Supreme Court declined to consider an appeal by Judicial Watch. Trump administration
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In 2020 Judicial Watch pursued emails related to the Steele Dossier, obtaining copies through a FOIA lawsuit. In the months prior to the 2020 election, Judicial Watch filed or threatened lawsuits against several states related to alleged inaccuracy of their voter rolls, demanding that nearly two million names be purged. Also in 2020, the group sued the state of California, claiming a law requiring corporations doing business in the state to have directors from sexual or racial minorities is unconstitutional, asserting "The legislation's requirement that certain corporations appoint a specific number of directors based upon race, ethnicity, sexual preference, and transgender status is immediately suspect and presumptively invalid and triggers strict scrutiny review by the court," Activities and controversies Judicial Watch's main targets have been Democrats, particularly Bill and Hillary Clinton and the Obama administration. Commerce Department trade mission scandal
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In 1995, Judicial Watch, Inc. filed an action in the District Court under the FOIA, seeking information from the Department of Commerce (DOC) regarding DOC's selection of participants for foreign trade missions. In May 1995, following a search in response to Judicial Watch's FOIA requests, DOC produced approximately 28,000 pages of nonexempt information and withheld about 1,000 documents as exempt. Disputes arose between the parties over the adequacy of DOC's search, and Judicial Watch charged that some DOC officials had destroyed or removed responsive documents. In December 1998, following discovery, the District Court granted partial summary judgment to Judicial Watch and ordered DOC to perform a new search. During the investigation, Nolanda B. Hill, a business partner of Commerce Secretary Ron Brown testified that Brown had told her that first lady Hillary Clinton was the driving force behind the efforts to raise as much money as possible for President Clinton's reelection and the
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DNC. And further that, "...companies were being solicited to donate large sums of money in exchange for their selection to participate on trade missions of the Commerce Department."
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Vince Foster conspiracy Judicial Watch helped promote the conspiracy theory that Vince Foster was murdered by the Clintons. White House visitor logs August 10, 2009 Judicial Watch sent a FOIA request to the US Secret Service asking that official White House visitor logs be made public. In August 2011, U.S. District Judge Beryl Howell ordered the agency to process the group's data request. The Court of Appeals for the District of Columbia partially affirmed the decision, holding that the Secret Service did not have to produce records of visitors to the president's office. False Nancy Pelosi claims In 2010, Judicial Watch made inaccurate claims about air travel spending by Nancy Pelosi's congressional delegation; Judicial Watch's claims were picked up by the conservative conspiracy site WorldNetDaily. Judicial Watch also made false claims about Pelosi's air travel in 2008. Operation Neptune Spear
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Osama bin Laden, leader of the terror group al-Qaeda, was killed in Pakistan on May 1, 2011, in a joint operation by the United States Navy SEALs and the Central Intelligence Agency (CIA). This operation was code-named Operation Neptune Spear. On May 2, 2011, Judicial Watch filed a FOIA request with the Department of Defense and the CIA for photographs and videos of bin Laden taken during or after the operation. The government failed to produce any records within the required twenty days. In order to force compliance, Judicial Watch filed a FOIA lawsuit against the DOD and CIA on June 8, 2011. On January 31, 2014, after legal wrangling, the Pentagon released Operation Neptune Spear documents to Judicial Watch. One email had the subject line OPSEC Guidance / Neptune Spear and is proof that days after the original FOIA request U.S. Special Operations Commander, Admiral William McRaven ordered his subordinates to immediately destroy any Osama bin Laden photos they may have had.
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Kennedy assassination records Judicial Watch filed a FOIA lawsuit against the National Archives and Records Administration (NARA) to obtain the records from Robert F. Kennedy's time as the Attorney General. The records covered sensitive intelligence operations conducted during the John F. Kennedy and Lyndon B. Johnson administrations. Hillary Clinton email lawsuits Judicial Watch has currently filed twenty FOIA lawsuits involving the Secretary of State Hillary Clinton's emails. On February 8, 2016, the FBI confirmed it was investigating Hillary Clinton's use of a private email server during her time as Secretary of State. The Bureau was forced to formally acknowledge the investigation due to an ongoing FOIA lawsuit brought by Judicial Watch. FBI director James Comey had previously referenced the investigation, although the FBI had declined to confirm or deny it in court filings.
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A federal judge ruled on February 23, 2016, that top aides to Hillary Clinton could be questioned under oath by Judicial Watch about her use of a private email server as secretary of state. District Court Judge Emmet G. Sullivan granted Judicial Watch's motion for discovery into whether the State Department and former Secretary of State Hillary Clinton deliberately thwarted the Freedom of Information Act by using a private email server to obscure her communications from public records requests.
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In May 2016 U.S. District Court Judge Emmet G. Sullivan granted "discovery" to Judicial Watch into former Secretary of State Hillary Clinton's email system. This ruling allowed Judicial Watch to question two close Clinton aides, Huma Abedin and Cheryl Mills, under oath. In a separate FOIA lawsuit concerning Hillary Clinton and the Benghazi terrorist attack, U.S. District Court Judge Royce Lamberth ruled Judicial Watch can conduct discovery into the email practices of Clinton and her top aides. In a separate case, on March 29, 2016, U.S. District Court Judge Royce Lamberth granted Judicial Watch limited discovery, citing potential bad faith by the government in responding to requests for documents related to talking points provided to Susan Rice in response to the Benghazi attack.
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A FOIA lawsuit by Judicial Watch led to the release of 2,800 e-mails from Clinton aide Huma Abedin that were found on the laptop computer of Anthony Weiner, Abedin's estranged husband. Five of the e-mails were classified. False claims about George Zimmermann protests In 2013, Judicial Watch claimed that the Department of Justice under the Obama administration organized protests against George Zimmermann after the Trayvon Martin shooting; PolitiFact said that this was "mostly false" and that while Justice Department employees were sent to Florida, they "were sent with the idea of keeping the situation peaceful and calm, not to instigate or condone protests or violence." ISIS in Mexico scares In 2014 and 2015, Judicial Watch falsely claimed that ISIS had set up camp in Mexico; Judicial Watch's claims were picked up by several right-wing news outlets. Collaboration with Steve Bannon and Breitbart News
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In 2013, Judicial Watch collaborated with Steve Bannon, executive chairman of the alt-right website Breitbart, on the film "District of Corruption", which critiqued the Obama administration. Judicial Watch paid Bannon's group Victory Film Project $382,143 for the film. Politico described the film as an "infomercial for the work of Judicial Watch". Judicial Watch has advertised on Breitbart for a number of years. Judicial Watch's president Tom Fitton said "Liberal activists want to destroy Breitbart, but we won't be cowed". Murder of Seth Rich conspiracy theory In 2017, Judicial Watch requested documents related to the death of DNC staffer Seth Rich; Seth Rich's death led to debunked rightwing conspiracy theories which alleged that Hillary Clinton or the Democratic Party had him killed. False voter fraud claims
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In August 2017, Judicial Watch falsely alleged that 11 California counties had more registered voters than their estimated populations of citizens eligible to vote; the claims were picked up by outlets such as Breitbart News and Russian propaganda network RT (Russia Today). Judicial Watch counted "inactive voters" in its tally, which is a list of people that California maintains of people who have been removed from active rolls after a mail ballot, voter guide or other official document was returned as undeliverable; California keeps such a list as a fail-safe in case eligible voters have been erroneously categorized as "inactive". California Secretary of State Alex Padilla said Judicial Watch's claims were "baseless", and "bad math and dubious methodology". When the Los Angeles Times asked Judicial Watch to share its analysis of voter registration in California, Judicial Watch declined. Judicial Watch's voter fraud claims came in the wake of President Donald Trump's false claims of
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extensive voter fraud in California during the 2016 presidential election. Trump has subsequently repeatedly promoted Judicial Watch's false claims about voter fraud.
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On February 3, 2020, the day of the Iowa caucuses in the Democratic presidential primary, JW president Tom Fitton suggested that voter fraud was afoot in Iowa by falsely claiming that "eight Iowa counties have more voter registrations than citizens old enough to register." The false assertion went viral on social media. Iowa's Secretary of State, Paul Pate, a member of the Republican Party, debunked Fitton's claim by linking to official voter registration data. Fitton has made alarmist claims about voter fraud, saying "We have all heard about voter fraud and the attempts by liberal media organs like the New York Times and Ivory Tower academics to dismiss it as a nonexistent problem. But is it real, widespread, and substantial to the point that it can decide elections." False claims about Trump Nazi billboard In 2017, Judicial Watch falsely claimed that taxpayer money went into a billboard which depicted President Donald Trump as a Nazi. Lawsuits against climate scientists
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Judicial Watch, which has claimed that climate science is "fraud science", has filed lawsuits seeking to force the National Oceanic and Atmospheric Administration (NOAA) to release the correspondence of climate scientists who published a 2015 study in the journal Science. The study had debunked one of the common claims made by those who reject the scientific consensus on climate change, namely that there existed global warming "hiatus" between 1998 and 2012. The Climate Science Legal Defense Fund (CSLDF), American Meteorological Society and Union of Concerned Scientists condemned Judicial Watch, saying that the disclosure of private communications between scientists "would harm (or halt altogether) government scientists' ability to collaborate with colleagues, damage the government's ability to recruit or retain top scientists, and deter critically important research into politically charged fields like climate change". The Judicial Watch lawsuit was inspired by Rep. Lamar Smith, a
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climate change denier who had accused the authors of the study of "alter[ing] data" to "get the politically correct results they want."
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Mueller and FBI investigations into Russian interference In 2017, Judicial Watch helped to stoke Republican attacks against Special Counsel Robert Mueller's investigation into Russian interference in the 2016 election. Judicial Watch President Tom Fitton has called for the Special Counsel investigation to be shut down, arguing that prosecutors in the probe were too biased against President Trump to conduct a credible investigation, a claim rejected by Republican Senators Tom Tillis and Bob Corker. Fitton furthermore called for shutting down the Federal Bureau of Investigation (FBI) based on the claim that the Obama administration had turned it into a "KGB-type operation."
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Accusations against the Clinton Foundation In January 2018, Judicial Watch president Tom Fitton repeated accusations against the Clinton Foundation that it had funneled money intended for charity work in Haiti to pay for Chelsea Clinton's wedding. The Washington Post fact-checked the claim a year earlier and found that it was "lacking any evidence". George Soros smears In October 2018, Chris Farrell of Judicial Watch stirred controversy when he appeared on Lou Dobbs' Fox Business show and used what many described as an anti-Semitic trope to suggest that the State Department was "Soros-occupied" territory. The remark echoed the anti-Semitic trope of a "Zionist-occupied government" to refer to Jewish control of the U.S. government. After widespread condemnation, Fox stated that Farrell would no longer be booked.
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Farrell promoted the unsubstantiated conspiracy theory that a migrant caravan traveling through Central America towards the United States was being directed or funded by the "Soros-occupied State Department". Judicial Watch had been engaged in what NPR described as a "full-throated campaign against Soros". Among other things, Judicial Watch raised money by running ads with a call to action: "Expose Soros!"
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Senator's letters to IRS According to Media Matters for America, in 2015, Judicial Watch claimed that three newly obtained letters sent by Democatic senator Carl Levin to the commissioner of the Internal Revenue Service "discuss how to target conservative groups the senator claimed were 'engaged in political activities'." Media Matters for America reported that Judicial Watch provided a link to the documents on its site, but said it failed to note that one Levin letter did not mention conservatives, while the other two mentioned an equal number of liberal/Democrat and conservative/Republican entities. The Judicial Watch claim was amplified by several conservative media outlets. Statue removal Judicial Watch has sought to remove a statue of Mexican revolutionary Pancho Villa from downtown Tucson. Judicial Watch said the statue "needs to go" because "Pancho Villa did great harm to people."
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2020 election voter suppression In 2020, Judicial Watch President Tom Fitton urged attendees of an event organized by the Council for National Policy to prevent mail-in ballots from being sent to voters, saying "We need to stop those ballots from going out, and I want the lawyers here to tell us what to do." Larry Klayman lawsuits In 2003, Judicial Watch founder Larry Klayman left the organization to run for the United States Senate from Florida. In 2006, Klayman sued Judicial Watch and its president, Tom Fitton. Judicial Watch asserted several claims against Klayman as well. In 2019, Judicial Watch obtained a $2.8 million verdict against Klayman on its claims of breaches of the severance agreement and trademark infringement.
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In 2012, a Judicial Watch employee falsely told Orly Taitz that Klayman had been convicted of not paying child support (Klayman had been indicted, but the charges were later dismissed). Taitz then published the employee's comment on her website. Klayman sued Judicial Watch for defamation, and in 2014, a federal jury awarded Klayman $156,000 in compensatory damages and $25,000 in punitive damages. In 2017, Freedom Watch (Klayman's successor organization to Judicial Watch) unsuccessfully sued Judicial Watch and the American Conservative Union (ACU), alleging they violated the Sherman Act by colluding to prevent Freedom Watch from participating at the ACU's Conservative Political Action Conference.
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Klayman had represented three individuals who sued Judicial Watch, his former employer and client, but he failed to obtain Judicial Watch's consent to waive his conflict of interest. Klayman maintained that the D.C. Bar had "recognized there was no evidence of dishonesty or personal gain". In 2020, however, the D.C. Court of Appeals suspended Klayman's license for 90 days and ordered him to complete a class on legal ethics. Peter Paul lawsuit In 2007 former donor Peter F. Paul sued Judicial Watch, accusing it of using his name to raise more than $15 million to support his lawsuit against Bill Clinton and Hillary Clinton while doing little to advance his case. All of Paul's claims were dismissed. Funding
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As of 2016, Judicial Watch has an annual budget of about $35 million. Between 1997 and 2002 Judicial Watch received $7,069,500 in 19 grants from a handful of foundations. The bulk of this funding came from three foundations: the Sarah Scaife Foundation, a funder of politically conservative causes; The Carthage Foundation, which merged into the Sarah Scaife Foundation in 2014; and the John M. Olin Foundation, Inc. As of 2010, the Sarah Scaife Foundation was the group's largest contributor. Notes Further reading Fitton, Tom The Corruption Chronicles: Obama's Big Secrecy, Big Corruption, and Big Government (New York: Simon & Schuster, 2012). Fitton, Tom Clean House: Exposing Our Government's Secrets and Lies (New York: Threshold Editions, 2016). External links Organizational Profile(archived) – National Center for Charitable Statistics (Urban Institute)
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Government watchdog groups in the United States Political organizations based in the United States 1994 establishments in the United States Organizations established in 1994 Conservative organizations in the United States Non-profit organizations based in Washington, D.C. Climate change denial Russian interference in the 2016 United States elections Conspiracy theories regarding Barack Obama Conspiracy theories promoted by Donald Trump
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A traction engine is a steam-powered tractor used to move heavy loads on roads, plough ground or to provide power at a chosen location. The name derives from the Latin tractus, meaning 'drawn', since the prime function of any traction engine is to draw a load behind it. They are sometimes called road locomotives to distinguish them from railway locomotives – that is, steam engines that run on rails. Traction engines tend to be large, robust and powerful, but also heavy, slow, and difficult to manoeuvre. Nevertheless, they revolutionized agriculture and road haulage at a time when the only alternative prime mover was the draught horse.
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They became popular in industrialised countries from around 1850, when the first self-propelled portable steam engines for agricultural use were developed. Production continued well into the early part of the 20th century, when competition from internal combustion engine-powered tractors saw them fall out of favour, although some continued in commercial use in the United Kingdom well into the 1950s and later. All types of traction engines have now been superseded in commercial use. However, several thousand examples have been preserved worldwide, many in working order. Steam fairs are held throughout the year in the United Kingdom, and in other countries, where visitors can experience working traction engines at close hand.
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Traction engines were cumbersome and ill-suited to crossing soft or heavy ground, so their agricultural use was usually either "on the belt" – powering farm machinery by means of a continuous leather belt driven by the flywheel, a form of power take-off – or in pairs, dragging an implement on a cable from one side of a field to another. However, where soil conditions permitted, direct hauling of implements ("off the drawbar") was preferred – in America, this led to the divergent development of the steam tractor. History Limits of technical knowledge and manufacturing technology meant that practicable road vehicles powered by steam did not start to appear until the early years of the 19th century.
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The traction engine, in the form recognisable today, was developed from an experiment in 1859 when Thomas Aveling modified a Clayton & Shuttleworth portable engine, which had to be hauled from job to job by horses, into a self-propelled one. This alteration was made by fitting a long driving chain between the crankshaft and the rear axle. Thomas Aveling is regarded as "the father of the traction engine". Other influences were existing vehicles which were the first to be referred to as traction engines such as the Boydell engines manufactured by various companies and those developed for road haulage by Bray. The first half of the 1860s was a period of great experimentation, but by the end of the decade the standard form of the traction engine had evolved and would change little over the next sixty years. Until the quality of roads improved there was little demand for faster vehicles, and engines were geared accordingly to cope with their use on rough roads and farm tracks.
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Right through to the first decades of the twentieth century, manufacturers continued to seek a solution to realise the economic benefits of direct-pull ploughing and, particularly in North America, this led to the American development of the steam tractor. British companies such as Mann's and Garrett developed potentially viable direct ploughing engines; however, market conditions were against them and they failed to gain widespread popularity. These market conditions arose in the wake of the First World War when there was a glut of surplus equipment available as a result of British Government policy. Large numbers of Fowler ploughing engines had been constructed in order to increase the land under tillage during the war and many new light Fordson F tractors had been imported from 1917 onwards. Decline
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Road steam disappeared through restrictions and charges that drove up their operating costs. Through 1921, steam tractors had demonstrated clear economic advantages over horse power for heavy hauling and short journeys. However, petrol lorries were starting to show better efficiency and could be purchased cheaply as war surplus; on a busy route a 3-ton petrol lorry could save about £100 per month compared to its steam equivalent, in spite of restrictive speed limits and relatively high fuel prices and maintenance costs.
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Throughout the 1920s and 1930s there were tighter restrictions on road steam haulage, including speed, smoke and vapour limits and a 'wetted tax', where the tax due was proportional to the size of the wetted area of the boiler; this made steam engines less competitive against domestically produced internal combustion engined units (although imports were subject to taxes of up to 33%). As a result of the Salter Report on road funding, an 'axle weight tax' was introduced in 1933 in order to charge commercial motor vehicles more for the costs of maintaining the road system and to do away with the perception that the free use of roads was subsidising the competitors of rail freight. The tax was payable by all road hauliers in proportion to the axle load and was particularly restrictive on steam propulsion, which was heavier than its petrol equivalent.
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Initially, imported oil was taxed much more than British-produced coal, but in 1934 Oliver Stanley, the Minister for Transport, reduced taxes on fuel oils while raising the Road Fund charge on road locomotives to £100 per year, provoking protests by engine manufacturers, hauliers, showmen and the coal industry. This was at a time of high unemployment in the mining industry, when the steam haulage business represented a market of 950,000 tons of coal annually. The tax was devastating to the businesses of heavy hauliers and showmen and precipitated the scrapping of many engines. The last new UK-built traction engines were constructed during the 1930s, although many continued in commercial use for many years while there remained experienced enginemen available to drive them.
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Preservation From the 1950s, the 'preservation movement' started to build as enthusiasts realised that traction engines were in danger of dying out. Many of the remaining engines were bought by enthusiasts, and restored to working order. Traction engine rallies began, initially as races between engine owners and their charges, later developing into the significant tourist attractions that take place in many locations each year.
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The Traction Engine Register records the details of traction engines, steam road rollers, steam wagons, steam fire engines and portable engines that are known to survive in the United Kingdom and Irish Republic. It recorded 2851 self moving engines and wagons, 687 portable engines (non-self moving), 160 steam fire engines existing in 2016. A new edition of the Register is planned in 2020. It was previously estimated in May 2011 by an unknown source that over 2,000 traction engines have been preserved. This figure may include engines preserved elsewhere in the world, particularly the US, Canada, Australia and New Zealand, but if so, is an underestimate. Comprehensive information on past UK manufacturers and their production is recorded by the Road Locomotive Society based in the UK. Operation See: steam engine for a description of how the actual engine worked.
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Although the first traction engines employed a chain drive, it is more typical for large gears to be used to transfer the drive from the crankshaft to the rear axle. The machines typically have two large powered wheels at the back and two smaller wheels for steering at the front. However, some traction engines used a four-wheel-drive variation, and some experimented with an early form of caterpillar track. Types and usage Traction engines saw commercial use in a variety of roles between the mid-nineteenth and mid-twentieth centuries. Each role required a machine with a different set of characteristics, and the traction engine evolved into a number of different types to suit these different roles. Agricultural (general purpose) engine
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The most common form in the countryside. They were used for hauling and as a stationary power source. Even when farmers did not own such a machine they would rely upon it from time to time. Many farms would use draught horses throughout the year, but during the harvest, threshing contractors would travel from farm to farm hauling the threshing machine which would be set up in the field and powered from the engine – a good example of the moveable stationary engine. US (agricultural) traction engine Favourable soil conditions meant that US traction engines usually pulled their ploughs behind them, thereby eliminating the complexities of providing a cable drum and extra gearing, hence simplifying maintenance. American traction engines were manufactured in a variety of sizes, with the 6 nhp Russell being the smallest commercially made, and the large engines made by Russell, Case, and Reeves being the largest. Ploughing engine
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A distinct form of traction engine, characterised by the provision of a large diameter winding drum driven by separate gearing from the steam engine. Onto the drum a long length of wire rope was wound, which was used to haul an implement, such as a plough, across a field, while the engine remained on the headland. This minimized the area of land subject to soil compaction. The winding drum was either mounted horizontally (below the boiler), vertically (to one side), or even concentrically, so that it encircled the boiler. The majority were underslung (horizontal), however, and necessitated the use of an extra-long boiler to allow enough space for the drum to fit between the front and back wheels. These designs were the largest and longest traction engines to be built.
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Mostly the ploughing engines worked in pairs, one on each side of the field, with the rope from each machine fastened to the implement to be hauled. The two drivers communicated by signals using the engine whistles. A variety of implements were constructed for use with ploughing engines. The most common were the balance plough and the cultivator - ploughing and cultivating being the most physically demanding jobs to do on an arable farm. Other implements could include a mole drainer, used to create an underground drainage channel or pipe, or a dredger bucket for dredging rivers or moats. The engines were frequently provided with a 'spud tray' on the front axle, to store the 'spuds' which would be fitted to the wheels when travelling across claggy ground.
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The man credited with the invention of the ploughing engine, in the mid-nineteenth century, was John Fowler, an English agricultural engineer and inventor. Though steam ploughing had been used as early as 1837, when John Heathcoat M.P. demonstrated a steam powered vehicle he designed for ploughing very soft ground. This used a very early form of continuous tracks, and its twin-cylinder steam engine could be either used for the ploughing winch or for propulsion. Another ploughing engine, devised by Peter, Lord Willoughby de Eresby and his bailiff George Gordon Scott, and constructed at Swindon Works, was exhibited at the Great Exhibition of 1851 in London, some years before Fowler's system appeared. Lord Willoughby had indicated that his design could be copied freely, and Fowler had visited Grimsthorpe Castle, the estate where the ploughing engines were deployed. Ploughing engines were rare in the US; ploughs were usually hauled directly by an agricultural engine or steam tractor.
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Steam tractor (US) In North America, the term steam tractor usually refers to a type of agricultural tractor powered by a steam engine, used extensively in the late 19th and early 20th centuries. Steam tractor (UK) In Great Britain, the term steam tractor is more usually applied to the smallest models of traction engine – typically those weighing below five tons for the engine to be single manned (anything above had to be manned by at least two people; a driver and steersman); used for hauling small loads on public roads. Although known as light steam tractors, these engines are generally just smaller versions of the road locomotive. They were popular in the timber trade in the UK, although variations were also designed for general light road haulage and showman's use. The most popular of these designs was probably the Garrett 4CD, meaning 4 nominal horse power Compound. Road locomotive
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Designed for haulage of heavy loads on public highways, it was common for two or even three to be coupled together to allow heavier loads to be handled. The characteristic features of these engines are very large rear driving wheels fitted with solid rubber tyres, three-speed gearing (most traction engine types have only two gears), rear suspension, and belly tanks to provide a greater range between the stops needed to replenish water. All these features are to improve the ride and performance of the engine, which were used for journeys of hundreds of miles. Most road locomotives are fitted with a winch drum on the back axle. This can be used by removing the driving pins from the rear wheels, allowing the drive train to power the winch drum instead of the wheels.
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James Boydell worked with the British steam traction engine manufacturer Charles Burrell & Sons to produce road haulage engines from 1856 that used his Dreadnaught Wheels which were particularly suited to bad roads or off-road use. A number of road locomotives are fitted with a crane boom on the front. The boom pivot is mounted on the front axle assembly and a small winch is mounted on an extension to the smokebox in front of the chimney, the cable passing over a sheave at the top of the boom arm. The winch is powered by bevel gears on a shaft driven directly from the engine, with some form of clutch providing raise/lower control. These road locomotives can be used to load a trailer as well as to haul it to a new location. They are often referred to as 'crane engines'.
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A particularly distinctive form of road locomotive was the showman's engine. These were operated by travelling showmen both to tow fairground equipment and to power it when set up, either directly or by running a generator. These could be highly decorated and formed part of the spectacle of the fair. Some were fitted with a small crane that could be used when assembling the ride. Steamroller Related to the steam traction engine, the steam roller was used for road building and flattening ground. Typically designed with a single heavy roller (in practice, usually a pair of adjacent rollers) replacing the front wheels and axle, and smooth rear wheels without strakes. Some traction engines were designed to be convertible: the same basic machine could be fitted with either standard () road wheels, or else smooth rolls – the changeover between the two being achieved in less than half a day. Relatives of the traction engine
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A number of other steam-powered vehicles share design features with the traction engine, usually because the same technology was re-used in a new application. Portable engine A portable engine is a type of self-contained steam engine and boiler combination that may be moved from site to site. Although bearing a strong family resemblance, in both appearance and (stationary) operation, the portable engine is not classed as a traction engine as it is not self-propelled. However, it is included in this list because the traction engine is a direct descendant. Steam wagon A steam wagon is a steam-powered road vehicle for carrying freight. It was the earliest form of lorry (truck) and came in two basic forms: overtype and undertype – the distinction being the position of the engine relative to the boiler. Among the firms that specialized in them in the 1900s was the short-lived Invicta Works of Maidstone, owned by Jesse Ellis.
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The overtype had a steam engine mounted on top of a fire-tube boiler, in a similar manner to a traction engine. The front of an overtype steam wagon bears a close family resemblance to traction engines, and manufacturers who made both may well have been able to use some common parts. The undertype had the steam engine mounted under the boiler, usually between the frames of the chassis. The boiler was usually mounted well forward and was often a vertical and/or water tube type. Steam wagons were the dominant form of powered road traction for commercial haulage in the early part of the twentieth century, although they were a largely British phenomenon, with few manufacturers outside Great Britain. Competition from internal-combustion-powered vehicles and adverse legislation meant that few remained in commercial use beyond the Second World War. Traction engines as railway locomotives
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Several traction engine builders (such as Aveling and Porter and Fowler) built light railway locomotives based on their traction engines. In their crudest form these simply had flanged steel wheels to enable them to run on rails. More sophisticated models had the boiler and engine mounted on a chassis which carried railway-wagon style axles. The rear axle was driven from the engine by gear or chain-drive. These unusual locomotives were sold to small industries for use in shunting and marshalling duties, although they also found favour with engineering firms engaged in the construction of mainline railways for hauling men, equipment and materials over the partly constructed line.
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Terminology spud or lug – strip of angled metal that could be bolted to the driving wheels to provide greater traction on soft or heavy ground. Spuds were often required on ploughing engines when moving across farmland. strake – name for the diagonal strips cast into or rivetted onto the wheel rims to provide traction on unmade ground (similar to the tread on a pneumatic tyre).
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Nominal horse power– nhp is the typical way that traction engines are rated. However, it has long been accepted that nominal horse power greatly understates the actual power of the engine. There are many ways to estimate the actual horse power but none of them gives an accurate answer, for example, a 4 nhp engine is said to be approximately ; however a 4 nhp engine can easily pull a laden 8-wheeler lorry while a diesel engine of cannot. Thus, many have resigned themselves that this debate will never be settled and, while nominal horsepower gives a convenient way of rating traction engines, it may never be converted accurately into diesel HP.
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Modern use Although no longer used commercially, traction engines of all types continue to be maintained and preserved by enthusiastic individuals and are frequently exhibited at agricultural shows in Europe (particularly the UK), Canada and the United States. They are often a main attraction in a live steam festival (see List of steam fairs). Model traction engines, powered by steam, are manufactured by several companies, notably Mamod and Wilesco. Larger scale model engines are popular subjects for model engineers to construct, either as a supplied kit of parts, or machined from raw materials. Traction engines in popular culture In film
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The 1962 film The Iron Maiden featured a showman's engine as the film's star, along with many others, at the annual rally at Woburn Abbey. In the 2004 film Tremors 4: The Legend Begins, the people of Rejection, Nevada had a traction engine and were proud of it. During the final battle, two of the characters fired their guns from the traction engine, and the traction engine rammed and killed the last graboid. In literature
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Trevor the Traction Engine is one of the non-railway characters featured in The Railway Series of children's books by the Rev. W. Awdry. Appearing in several of the books, the traction engine was originally 'saved from scrap' by The Vicar of Wellsworth with the help of Edward the Blue Engine. Trevor has also appeared in a number of episodes in the TV spin-off Thomas & Friends. Another traction engine, Fergus the Railway Traction Engine, also appears in Thomas & Friends, but unlike Trevor, Fergus runs on rails instead of roads. Theo from Journey Beyond Sodor is based on a Brill Tramway No. 1.
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In the book Gumdrop and The Farmer's Friend, by Val Biro, the vintage motor-car Gumdrop is rescued from a snowy ditch by "The Farmer's Friend", a traction engine belonging to a local farmer. Some months later, the two vehicles are instrumental in thwarting a pair of car thieves. The end-papers of the book include a simplified cut-away drawing of the traction engine: a single-cylinder, 6 nhp Fowler light tractor built in 1903. Traction engines for road haulage feature prominently in Keith Roberts' alternate-history novel Pavane. In the 1960s, cutaway drawings of traction engines by Geoffrey Wheeler featured in Eagle comics and a Blue Peter annual.
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On television Fred Dibnah of Bolton, England, was known as a National Institution in Great Britain for the conservation of old traction engines and other steam engines. His television series Fred Dibnah's Made in Britain shows him touring the United Kingdom in his rebuilt 10-ton traction engine. In the television play Threads, depicting the consequences of nuclear war in the United Kingdom, traction engines come back into use as petrol becomes unavailable. Manufacturers See also Farm equipment History of steam road vehicles Hollycombe Steam Collection List of steam fairs – where preserved traction engines may be seen in action Live steam Museum of English Rural Life (MERL) – UK national collection of history of farming Steam car Steam roller Steam shovel Steam tractor Steam tricycle Steam wagon Steam locomotive Stationary steam engine References External links
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Research Database of historical agricultural engineering companies of the UK – (MERL) Steam Traction magazine – searchable article archive (1951-date)    Covers US traction engines and steam tractors, threshing machines and steam-powered agricultural machinery. Steam Scenes – extensive searchable photo library – preserved traction engines in the UK, Europe, Australia and New Zealand Steam-Up – photo library – UK-based preserved traction engines Traction Time – vast searchable photo library & discussion forums – Information about UK-based traction engines History
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Concise history of the traction engine – evolution, from earliest experiments to widespread manufacture, plus definitions of the six main types History of steam ploughing – particularly covers the very early years as different techniques were tried Transactions of the Highland and Agricultural Society of Scotland – (c.1871) report of trial of Fiskens Steam Cultivation Machinery (a windlass ploughing apparatus) -- including description and diagram History of Waterloo Gasoline Traction Engine Company (Iowa) – the first gasoline-powered traction engine, and forerunner of the John Deere tractor range "Steam Dinosaur" – world's oldest surviving traction engine (plus much history of early Aveling products) The Road Locomotive Society – charitable society founded in 1937 for education and research into history of traction engines and portable engines
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Preservation Hollycombe Steam Collection Aspects of restoring and owning a traction engine National Traction Engine Trust East Anglian Traction Engine Society Engine Resources UK Traction engine rallies Steam Traction Engine – episode of The Heartland Series Further information Interactive diagram of a traction engine showing major components. Glossary of traction engine terminology Definition of nominal horse power – also see Nominal Horse Power Vintage Spirit magazine Old Glory magazine Types of Steam Traction Engines The Traction Engine Register – The official website of The Traction Engine Register Steam engines Steam road vehicles Agricultural machinery Articles containing video clips
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Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses short-wavelength ultraviolet (ultraviolet C or UV-C) light to kill or inactivate microorganisms by destroying nucleic acids and disrupting their DNA, leaving them unable to perform vital cellular functions. UVGI is used in a variety of applications, such as food, air, and water purification. UV-C light is weak at the Earth's surface since the ozone layer of the atmosphere blocks it. UVGI devices can produce strong enough UV-C light in circulating air or water systems to make them inhospitable environments to microorganisms such as bacteria, viruses, molds, and other pathogens. UVGI can be coupled with a filtration system to sanitize air and water.
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The application of UVGI to disinfection has been an accepted practice since the mid-20th century. It has been used primarily in medical sanitation and sterile work facilities. Increasingly, it has been employed to sterilize drinking and wastewater since the holding facilities are enclosed and can be circulated to ensure a higher exposure to the UV. UVGI has found renewed application in air purifiers. History In 1878, Arthur Downes and Thomas P. Blunt published a paper describing the sterilization of bacteria exposed to short-wavelength light. UV has been a known mutagen at the cellular level for over 100 years. The 1903 Nobel Prize for Medicine was awarded to Niels Finsen for his use of UV against lupus vulgaris, tuberculosis of the skin.
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Using UV light for disinfection of drinking water dates back to 1910 in Marseille, France. The prototype plant was shut down after a short time due to poor reliability. In 1955, UV water treatment systems were applied in Austria and Switzerland; by 1985 about 1,500 plants were employed in Europe. In 1998 it was discovered that protozoa such as cryptosporidium and giardia were more vulnerable to UV light than previously thought; this opened the way to wide-scale use of UV water treatment in North America. By 2001, over 6,000 UV water treatment plants were operating in Europe. Over time, UV costs have declined as researchers develop and use new UV methods to disinfect water and wastewater. Several countries have published regulations and guidance for the use of UV to disinfect drinking water supplies Examples include the US. and in the UK . Method of operation
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UV light is electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays. UV is categorised into several wavelength ranges, with short-wavelength UV (UV-C) considered "germicidal UV". Wavelengths between about 200 nm and 300 nm are strongly absorbed by nucleic acids. The absorbed energy can result in defects including pyrimidine dimers. These dimers can prevent replication or can prevent the expression of necessary proteins, resulting in the death or inactivation of the organism. Mercury-based lamps operating at low vapor pressure emit UV light at the 253.7 nm line. Ultraviolet light-emitting diode (UV-C LED) lamps emit UV light at selectable wavelengths between 255 and 280 nm. Pulsed-xenon lamps emit UV light across the entire UV spectrum with a peak emission near 230 nm.
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This process is similar to, but stronger than, the effect of longer wavelengths (UV-B) producing sunburn in humans. Microorganisms have less protection against UV and cannot survive prolonged exposure to it. A UVGI system is designed to expose environments such as water tanks, sealed rooms and forced air systems to germicidal UV. Exposure comes from germicidal lamps that emit germicidal UV at the correct wavelength, thus irradiating the environment. The forced flow of air or water through this environment ensures exposure. Effectiveness The effectiveness of germicidal UV depends on the duration a microorganism is exposed to UV, the intensity and wavelength of the UV radiation, the presence of particles that can protect the microorganisms from UV, and a microorganism's ability to withstand UV during its exposure.
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In many systems, redundancy in exposing microorganisms to UV is achieved by circulating the air or water repeatedly. This ensures multiple passes so that the UV is effective against the highest number of microorganisms and will irradiate resistant microorganisms more than once to break them down. "Sterilization" is often misquoted as being achievable. While it is theoretically possible in a controlled environment, it is very difficult to prove and the term "disinfection" is generally used by companies offering this service as to avoid legal reprimand. Specialist companies will often advertise a certain log reduction, e.g., 6-log reduction or 99.9999% effective, instead of sterilization. This takes into consideration a phenomenon known as light and dark repair (photoreactivation and base excision repair, respectively), in which a cell can repair DNA that has been damaged by UV light.
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The effectiveness of this form of disinfection depends on line-of-sight exposure of the microorganisms to the UV light. Environments where design creates obstacles that block the UV light are not as effective. In such an environment, the effectiveness is then reliant on the placement of the UVGI system so that line of sight is optimum for disinfection. Dust and films coating the bulb lower UV output. Therefore, bulbs require periodic cleaning and replacement to ensure effectiveness. The lifetime of germicidal UV bulbs varies depending on design. Also, the material that the bulb is made of can absorb some of the germicidal rays. Lamp cooling under airflow can also lower UV output. Increases in effectiveness and UV intensity can be achieved by using reflection. Aluminum has the highest reflectivity rate versus other metals and is recommended when using UV.
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One method for gauging UV effectiveness in water disinfection applications is to compute UV dose. EPA published UV dosage guidelines for water treatment applications in 1986. UV dose cannot be measured directly but can be inferred based on the known or estimated inputs to the process: Flow rate (contact time) Transmittance (light reaching the target) Turbidity (cloudiness) Lamp age or fouling or outages (reduction in UV intensity) In air and surface disinfection applications the UV effectiveness is estimated by calculating the UV dose which will be delivered to the microbial population. The UV dose is calculated as follows: UV dose (μW·s/cm2) = UV intensity (μW/cm2) × exposure time (seconds)
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The UV intensity is specified for each lamp at a distance of 1 meter. UV intensity is inversely proportional to the square of the distance so it decreases at longer distances. Alternatively, it rapidly increases at distances shorter than 1m. In the above formula, the UV intensity must always be adjusted for distance unless the UV dose is calculated at exactly from the lamp. Also, to ensure effectiveness, the UV dose must be calculated at the end of lamp life (EOL is specified in number of hours when the lamp is expected to reach 80% of its initial UV output) and at the furthest distance from the lamp on the periphery of the target area. Some shatter-proof lamps are coated with a fluorated ethylene polymer to contain glass shards and mercury in case of breakage; this coating reduces UV output by as much as 20%.
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To accurately predict what UV dose will be delivered to the target, the UV intensity, adjusted for distance, coating, and end of lamp life, will be multiplied by the exposure time. In static applications the exposure time can be as long as needed for an effective UV dose to be reached. In case of rapidly moving air, in AC air ducts, for example, the exposure time is short, so the UV intensity must be increased by introducing multiple UV lamps or even banks of lamps. Also, the UV installation must be located in a long straight duct section with the lamps perpendicular to the airflow to maximize the exposure time.
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These calculations actually predict the UV fluence and it is assumed that the UV fluence will be equal to the UV dose. The UV dose is the amount of germicidal UV energy absorbed by a microbial population over a period of time. If the microorganisms are planktonic (free floating) the UV fluence will be equal the UV dose. However, if the microorganisms are protected by mechanical particles, such as dust and dirt, or have formed biofilm a much higher UV fluence will be needed for an effective UV dose to be introduced to the microbial population.
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Inactivation of microorganisms The degree of inactivation by ultraviolet radiation is directly related to the UV dose applied to the water. The dosage, a product of UV light intensity and exposure time, is usually measured in microjoules per square centimeter, or equivalently as microwatt seconds per square centimeter (μW·s/cm2). Dosages for a 90% kill of most bacteria and viruses range between 2,000 and 8,000 μW·s/cm2. Larger parasites such as cryptosporidium require a lower dose for inactivation. As a result, US EPA has accepted UV disinfection as a method for drinking water plants to obtain cryptosporidium, giardia or virus inactivation credits. For example, for a 90% reduction of cryptosporidium, a minimum dose of 2,500 μW·s/cm2 is required based on EPA's 2006 guidance manual. Strengths and weaknesses Advantages
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UV water treatment devices can be used for well water and surface water disinfection. UV treatment compares favourably with other water disinfection systems in terms of cost, labour and the need for technically trained personnel for operation. Water chlorination treats larger organisms and offers residual disinfection, but these systems are expensive because they need special operator training and a steady supply of a potentially hazardous material. Finally, boiling of water is the most reliable treatment method but it demands labour and imposes a high economic cost. UV treatment is rapid and, in terms of primary energy use, approximately 20,000 times more efficient than boiling.
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Disadvantages UV disinfection is most effective for treating high-clarity, purified reverse osmosis distilled water. Suspended particles are a problem because microorganisms buried within particles are shielded from the UV light and pass through the unit unaffected. However, UV systems can be coupled with a pre-filter to remove those larger organisms that would otherwise pass through the UV system unaffected. The pre-filter also clarifies the water to improve light transmittance and therefore UV dose throughout the entire water column. Another key factor of UV water treatment is the flow rate—if the flow is too high, water will pass through without sufficient UV exposure. If the flow is too low, heat may build up and damage the UV lamp.
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A disadvantage of UVGI is that while water treated by chlorination is resistant to reinfection (until the chlorine off-gasses), UVGI water is not resistant to reinfection. UVGI water must be transported or delivered in such a way as to avoid reinfection. Safety To humans UV light is hazardous to most living things. Skin exposure to germicidal wavelengths of UV light can produce rapid sunburn and skin cancer. Exposure of the eyes to this UV radiation can produce extremely painful inflammation of the cornea and temporary or permanent vision impairment, up to and including blindness in some cases. Common precautions are:
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Warning labels warn humans about dangers of UV light. In home settings with children and pets, doors are additionally necessary. Interlock systems. Shielded systems where the light is blocked inside, such as a closed water tank or closed air circulation system, often has interlocks that automatically shut off the UV lamps if the system is opened for access by humans. Clear viewports that block UVC are available. Protective gear. Most protective eyewear (in particular, all ANSI Z87.1-compliant eyewear) block UVC. Clothing, plastics, and most types of glass (but not fused silica) are effective in blocking UVC.
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Another potential danger is the UV production of ozone, which can be harmful when inhaled. US EPA designated 0.05 parts per million (ppm) of ozone to be a safe level. Lamps designed to release UV and higher frequencies are doped so that any UV light below 254 nm wavelengths will not be released, to minimize ozone production. A full-spectrum lamp will release all UV wavelengths and produce ozone when UV-C hits oxygen (O2) molecules.
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The American Conference of Governmental Industrial Hygienists (ACGIH) Committee on Physical Agents has established a threshold limit value (TLV) for UV exposure to avoid such skin and eye injuries among those most susceptible. For 254 nm UV, this TLV is 6 mJ/cm2 over an eight-hour period. The TLV function differs by wavelengths because of variable energy and potential for cell damage. This TLV is supported by the International Commission on Non-Ionizing Radiation Protection and is used in setting lamp safety standards by the Illuminating Engineering Society of North America. When the Tuberculosis Ultraviolet Shelter Study was planned, this TLV was interpreted as if eye exposure in rooms was continuous over eight hours and at the highest eye-level irradiance found in the room. In those highly unlikely conditions, a 6.0 mJ/cm2 dose is reached under the ACGIH TLV after just eight hours of continuous exposure to an irradiance of 0.2 μW/cm2. Thus, 0.2 μW/cm2 was widely interpreted as the
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upper permissible limit of irradiance at eye height.
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According to the FDA, a germicidal excimer lamp that emits 222 nm light instead of the common 254 nm light is safer to mamallian skin. To items UVC radiation is able to break down chemical bonds. This leads to rapid aging of plastics, insulation, gaskets, and other materials. Note that plastics sold to be "UV-resistant" are tested only for the lower-energy UVB since UVC does not normally reach the surface of the Earth. When UV is used near plastic, rubber, or insulation, these materials may be protected by metal tape or aluminum foil. Uses Air disinfection UVGI can be used to disinfect air with prolonged exposure. In the 1930s and 40s, an experiment in public schools in Philadelphia showed that upper-room ultraviolet fixtures could significantly reduce the transmission of measles among students. In 2020, UVGI is again being researched as a possible countermeasure against the COVID-19 pandemic.
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UV and violet light are able to neutralize the infectivity of SARS-CoV-2. Viral titers usually found in the sputum of COVID-19 patients are completely inactivated by levels of UV-A and UV-B irradiation that are similar to those levels experienced from natural sun exposure. This finding suggests that the reduced incidence of SARS-COV-2 in the summer may be, in part, due to the neutralizing activity of solar UV irradiation. Various UV-emitting devices can be used for SARS-CoV-2 disinfection, and these devices may help in reducing the spread of infection. SARS-CoV-2 can be inactivated by a wide range of UVC wavelengths, and the wavelength of 222nm provides the most effective disinfection performance.
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Disinfection is a function of UV intensity and time. For this reason, it is in theory not as effective on moving air, or when the lamp is perpendicular to the flow, as exposure times are dramatically reduced. However, numerous professional and scientific publications have indicated that the overall effectiveness of UVGI actually increases when used in conjunction with fans and HVAC ventilation, which facilitate whole-room circulation that exposes more air to the UV source. Air purification UVGI systems can be free-standing units with shielded UV lamps that use a fan to force air past the UV light. Other systems are installed in forced air systems so that the circulation for the premises moves microorganisms past the lamps. Key to this form of sterilization is placement of the UV lamps and a good filtration system to remove the dead microorganisms. For example, forced air systems by design impede line-of-sight, thus creating areas of the environment that will be shaded from the UV
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light. However, a UV lamp placed at the coils and drain pans of cooling systems will keep microorganisms from forming in these naturally damp places.
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Water disinfection Ultraviolet disinfection of water is a purely physical, chemical-free process. Even parasites such as Cryptosporidium or Giardia, which are extremely resistant to chemical disinfectants, are efficiently reduced. UV can also be used to remove chlorine and chloramine species from water; this process is called photolysis, and requires a higher dose than normal disinfection. The dead microorganisms are not removed from the water. UV disinfection does not remove dissolved organics, inorganic compounds or particles in the water. The world's largest water disinfection plant treats drinking water for New York City. The Catskill-Delaware Water Ultraviolet Disinfection Facility, commissioned on 8 October 2013, incorporates a total of 56 energy-efficient UV reactors treating up to a day. Ultraviolet can also be combined with ozone or hydrogen peroxide to produce hydroxyl radicals to break down trace contaminants through an advanced oxidation process.
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It used to be thought that UV disinfection was more effective for bacteria and viruses, which have more-exposed genetic material, than for larger pathogens that have outer coatings or that form cyst states (e.g., Giardia) that shield their DNA from UV light. However, it was recently discovered that ultraviolet radiation can be somewhat effective for treating the microorganism Cryptosporidium. The findings resulted in the use of UV radiation as a viable method to treat drinking water. Giardia in turn has been shown to be very susceptible to UV-C when the tests were based on infectivity rather than excystation. It has been found that protists are able to survive high UV-C doses but are sterilized at low doses.
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Developing countries A 2006 project at University of California, Berkeley produced a design for inexpensive water disinfection in resource deprived settings. The project was designed to produce an open source design that could be adapted to meet local conditions. In a somewhat similar proposal in 2014, Australian students designed a system using potato chip (crisp) packet foil to reflect solar UV radiation into a glass tube that disinfects water without power.
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Wastewater treatment Ultraviolet in sewage treatment is commonly replacing chlorination. This is in large part because of concerns that reaction of the chlorine with organic compounds in the waste water stream could synthesize potentially toxic and long lasting chlorinated organics and also because of the environmental risks of storing chlorine gas or chlorine containing chemicals. Individual wastestreams to be treated by UVGI must be tested to ensure that the method will be effective due to potential interferences such as suspended solids, dyes, or other substances that may block or absorb the UV radiation. According to the World Health Organization, "UV units to treat small batches (1 to several liters) or low flows (1 to several liters per minute) of water at the community level are estimated to have costs of US$20 per megaliter, including the cost of electricity and consumables and the annualized capital cost of the unit."
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Large-scale urban UV wastewater treatment is performed in cities such as Edmonton, Alberta. The use of ultraviolet light has now become standard practice in most municipal wastewater treatment processes. Effluent is now starting to be recognized as a valuable resource, not a problem that needs to be dumped. Many wastewater facilities are being renamed as water reclamation facilities, whether the wastewater is discharged into a river, used to irrigate crops, or injected into an aquifer for later recovery. Ultraviolet light is now being used to ensure water is free from harmful organisms. Aquarium and pond Ultraviolet sterilizers are often used to help control unwanted microorganisms in aquaria and ponds. UV irradiation ensures that pathogens cannot reproduce, thus decreasing the likelihood of a disease outbreak in an aquarium.
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Aquarium and pond sterilizers are typically small, with fittings for tubing that allows the water to flow through the sterilizer on its way from a separate external filter or water pump. Within the sterilizer, water flows as close as possible to the ultraviolet light source. Water pre-filtration is critical as water turbidity lowers UV-C penetration. Many of the better UV sterilizers have long dwell times and limit the space between the UV-C source and the inside wall of the UV sterilizer device. Laboratory hygiene UVGI is often used to disinfect equipment such as safety goggles, instruments, pipettors, and other devices. Lab personnel also disinfect glassware and plasticware this way. Microbiology laboratories use UVGI to disinfect surfaces inside biological safety cabinets ("hoods") between uses.
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Food and beverage protection Since the U.S. Food and Drug Administration issued a rule in 2001 requiring that virtually all fruit and vegetable juice producers follow HACCP controls, and mandating a 5-log reduction in pathogens, UVGI has seen some use in sterilization of juices such as fresh-pressed. Technology Lamps Germicidal UV for disinfection is most typically generated by a mercury-vapor lamp. Low-pressure mercury vapor has a strong emission line at 254 nm, which is within the range of wavelengths that demonstrate strong disinfection effect. The optimal wavelengths for disinfection are close to 260 nm.
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Mercury vapor lamps may be categorized as either low-pressure (including amalgam) or medium-pressure lamps. Low-pressure UV lamps offer high efficiencies (approx. 35% UV-C) but lower power, typically 1 W/cm power density (power per unit of arc length). Amalgam UV lamps utilize an amalgam to control mercury pressure to allow operation at a somewhat higher temperature and power density. They operate at higher temperatures and have a lifetime of up to 16,000 hours. Their efficiency is slightly lower than that of traditional low-pressure lamps (approx. 33% UV-C output), and power density is approximately 2–3 W/cm3. Medium-pressure UV lamps operate at much higher temperatures, up to about 800 degrees Celsius, and have a polychromatic output spectrum and a high radiation output but lower UV-C efficiency of 10% or less. Typical power density is 30 W/cm3 or greater.
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Depending on the quartz glass used for the lamp body, low-pressure and amalgam UV emit radiation at 254 nm and also at 185 nm, which has chemical effects. UV radiation at 185 nm is used to generate ozone. The UV lamps for water treatment consist of specialized low-pressure mercury-vapor lamps that produce ultraviolet radiation at 254 nm, or medium-pressure UV lamps that produce a polychromatic output from 200 nm to visible and infrared energy. The UV lamp never contacts the water; it is either housed in a quartz glass sleeve inside the water chamber or mounted externally to the water, which flows through the transparent UV tube. Water passing through the flow chamber is exposed to UV rays, which are absorbed by suspended solids, such as microorganisms and dirt, in the stream. Light emitting diodes (LEDs)
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Recent developments in LED technology have led to commercially available UV-C LEDs. UV-C LEDs use semiconductors to emit light between 255 nm and 280 nm. The wavelength emission is tuneable by adjusting the material of the semiconductor. , the electrical-to-UV-C conversion efficiency of LEDs was lower than that of mercury lamps. The reduced size of LEDs opens up options for small reactor systems allowing for point-of-use applications and integration into medical devices. Low power consumption of semiconductors introduce UV disinfection systems that utilized small solar cells in remote or Third World applications.
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UV-C LEDs don't necessarily last longer than traditional germicidal lamps in terms of hours used, instead having more-variable engineering characteristics and better tolerance for short-term operation. A UV-C LED can achieve a longer installed time than a traditional germicidal lamp in intermittent use. Likewise, LED degradation increases with heat, while filament and HID lamp output wavelength is dependent on temperature, so engineers can design LEDs of a particular size and cost to have a higher output and faster degradation or a lower output and slower decline over time.
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Water treatment systems Sizing of a UV system is affected by three variables: flow rate, lamp power, and UV transmittance in the water. Manufacturers typically developed sophisticated computational fluid dynamics (CFD) models validated with bioassay testing. This involves testing the UV reactor's disinfection performance with either MS2 or T1 bacteriophages at various flow rates, UV transmittance, and power levels in order to develop a regression model for system sizing. For example, this is a requirement for all public water systems in the United States per the EPA UV manual.
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The flow profile is produced from the chamber geometry, flow rate, and particular turbulence model selected. The radiation profile is developed from inputs such as water quality, lamp type (power, germicidal efficiency, spectral output, arc length), and the transmittance and dimension of the quartz sleeve. Proprietary CFD software simulates both the flow and radiation profiles. Once the 3D model of the chamber is built, it is populated with a grid or mesh that comprises thousands of small cubes.
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Points of interest—such as at a bend, on the quartz sleeve surface, or around the wiper mechanism—use a higher resolution mesh, whilst other areas within the reactor use a coarse mesh. Once the mesh is produced, hundreds of thousands of virtual particles are "fired" through the chamber. Each particle has several variables of interest associated with it, and the particles are "harvested" after the reactor. Discrete phase modeling produces delivered dose, head loss, and other chamber-specific parameters. When the modeling phase is complete, selected systems are validated using a professional third party to provide oversight and to determine how closely the model is able to predict the reality of system performance. System validation uses non-pathogenic surrogates such as MS 2 phage or Bacillus subtilis to determine the Reduction Equivalent Dose (RED) ability of the reactors. Most systems are validated to deliver 40 mJ/cm2 within an envelope of flow and transmittance.
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To validate effectiveness in drinking water systems, the method described in the EPA UV guidance manual is typically used by US water utilities, whilst Europe has adopted Germany's DVGW 294 standard. For wastewater systems, the NWRI/AwwaRF Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse protocols are typically used, especially in wastewater reuse applications. See also HEPA filter Portable water purification Sanitation Sanitation Standard Operating Procedures Solar water disinfection References External links International Ultraviolet Association Radiobiology Ultraviolet radiation Hygiene Waste treatment technology Sterilization (microbiology)
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Bungie, Inc. is an American video game developer based in Bellevue, Washington. The company was established in May 1991 by Alex Seropian, who later brought in programmer Jason Jones after publishing Jones' game Minotaur: The Labyrinths of Crete. Originally based in Chicago, Illinois, the company concentrated on Macintosh games during its early years and created two successful video game franchises called Marathon and Myth. An offshoot studio, Bungie West, produced Oni, published in 2001 and owned by Take-Two Interactive, which held a 19.9% ownership stake at the time.
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Microsoft acquired Bungie in 2000, and its project Halo: Combat Evolved was repurposed as a launch title for Microsoft's Xbox console. Halo became the Xbox's "killer app", selling millions of copies and spawning the Halo franchise. On October 5, 2007, Bungie announced that it had split from Microsoft and become a privately held independent company, Bungie LLC, while Microsoft retained ownership of the Halo franchise intellectual property. It signed a ten-year publishing deal with Activision in April 2010. Their first project was the 2014 first-person shooter, Destiny, which was followed by Destiny 2 in 2017. In January 2019, Bungie announced it was ending this partnership, and would take over publishing for Destiny. In January 2022, Sony Interactive Entertainment announced their intent to acquire Bungie as part of their family of studios, though Bungie would remain an independent and multi-platform studio and publisher.
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Among Bungie's side projects is Bungie.net, the company's website, which includes company information, forums, and statistics-tracking and integration with many of its games. Bungie.net serves as the platform from which Bungie sells company-related merchandise out of the Bungie Store and runs other projects, including Bungie Aerospace, charitable organization the Bungie Foundation, a podcast, and online publications about game topics. The company is known for its informal and dedicated workplace culture. History Background and founding (1990–1993) In the early 1990s, Alex Seropian was pursuing a mathematics degree at the University of Chicago, as the university did not offer undergraduate degrees in computer science. Living at home shortly before graduation, his father's wishes for him to get a job convinced Seropian to start his own game company instead.