who discovered that air is made up of several gases
Priestley
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Joseph Priestley Joseph Priestley (; – 6 February 1804) was an 18th-century English Separatist theologian, natural philosopher, chemist, innovative grammarian, multi-subject educator, and liberal political theorist who published over 150 works. He has historically been credited with the discovery of oxygen, having isolated it in its gaseous state, although Carl Wilhelm Scheele and Antoine Lavoisier also have strong claims to the discovery. During his lifetime, Priestley's considerable scientific reputation rested on his invention of soda water, his writings on electricity, and his discovery of several "airs" (gases), the most famous being what Priestley dubbed "dephlogisticated air" (oxygen). However, Priestley's determination
Joseph Priestley
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day. Before his work, though, many important discoveries had been made, specifically relating to the nature of 'air' which was discovered to be composed of many different gases. The Scottish chemist Joseph Black (the first experimental chemist) and the Dutchman J.B. van Helmont discovered carbon dioxide, or what Black called 'fixed air' in 1754; Henry Cavendish discovered hydrogen and elucidated its properties and Joseph Priestley and, independently, Carl Wilhelm Scheele isolated pure oxygen. English scientist John Dalton proposed the modern theory of atoms; that all substances are composed of indivisible 'atoms' of matter and that different atoms have varying atomic
Chemistry
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paper on the production of water by burning inflammable air (that is, hydrogen) in dephlogisticated air (now known to be oxygen), the latter a constituent of atmospheric air (phlogiston theory). In 1773, Swedish chemist Carl Wilhelm Scheele discovered oxygen, which he called "fire air", but did not immediately publish his achievement. In 1774, English chemist Joseph Priestley independently isolated oxygen in its gaseous state, calling it "dephlogisticated air", and published his work before Scheele. During his lifetime, Priestley's considerable scientific reputation rested on his invention of soda water, his writings on electricity, and his discovery of several "airs" (gases), the
History of chemistry
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gases that were usually soluble in water. From these experiments Priestley is credited with discovering many new gases such as oxygen, hydrogen chloride, and ammonia. He also discovered a way to find the purity or “goodness” of air using “nitrous air test”. This test was conducted by mixing nitrous gas with a test sample of another gas and trapping it in the pneumatic trough, essentially the greater the decrease in volume, the more pure the sample of gas was (key principle in eudiometry). Henry Cavendish later used a similar device to determine the fraction of oxygen in the Earth's atmosphere.
Eudiometer
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laid the foundations for his discovery, Lavoisier claimed he had discovered oxygen; Priestley, after all, had failed to recognise it as a new element. Lavoisier went on to give science its first definition of an element: a substance that cannot be decomposed by existing chemical means. He also set about drawing up a list of all the elements – now 33 elements replaced the ancient four. His list was grouped into four categories: gases, non-metals, metals and earths. On top of this, Lavoisier created a classification system for the ever-increasing array of chemicals being discovered. As mentioned, ‘dephlogisticated air’ became
Chemistry: A Volatile History
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discovered "vitriolic acid air" (sulphur dioxide, SO). In March he wrote to several people regarding the new "air" that he had discovered in August. One of these letters was read aloud to the Royal Society, and a paper outlining the discovery, titled "An Account of further Discoveries in Air", was published in the Society's journal "Philosophical Transactions". Priestley called the new substance "dephlogisticated air", which he made in the famous experiment by focusing the sun’s rays on a sample of mercuric oxide. He first tested it on mice, who surprised him by surviving quite a while entrapped with the air,
Joseph Priestley
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The resulting product was termed "calx", which was considered a 'dephlogisticated' substance in its 'true' form. The first strong evidence against phlogiston theory came from pneumatic chemists in Britain during the later half of the 18th century. Joseph Black, Joseph Priestley and Henry Cavendish all identified different gases that composed air; however, it was not until Antoine Lavoisier discovered in the fall of 1772 that, when burned, sulphur and phosphorus “gain[ed] in weight” that the phlogiston theory began to unravel. Lavoisier subsequently discovered and named oxygen, described its role in animal respiration and the calcination of metals exposed to air
Science in the Age of Enlightenment
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works at Tipton, near Dudley, for the manufacture of alkali from the sulfates of potash and soda, to which he afterwards added a soap manufactory. The method of extraction proceeded on a discovery of Keir's. A nearby road was called Soap Factory Road, though it is now called Factory Road. When Joseph Priestley came to Birmingham in 1780, he found an able assistant in Keir, who had discovered the distinction between carbon dioxide gas and atmospheric air. Keir worked closely with Priestley to investigate the properties of gases. On 3 May 1787 Keir communicated to the Royal Society some "Experiments
James Keir
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law", as Gay-Lussac gave credit to Jacques Charles, who had arrived at nearly the same conclusion in the 1780s but had not published it. The law was independently discovered by British natural philosopher John Dalton by 1801, although Dalton's description was less thorough than Gay-Lussac's. In 1804 Gay-Lussac made several daring ascents of over 7,000 meters above sea level in hydrogen-filled balloons—a feat not equaled for another 50 years—that allowed him to investigate other aspects of gases. Not only did he gather magnetic measurements at various altitudes, but he also took pressure, temperature, and humidity measurements and samples of air,
History of chemistry
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Mond gas Mond gas is a cheap coal gas that was used for industrial heating purposes. Coal gases are made by decomposing coal through heating it to a high temperature. Coal gases were the primary source of gas fuel during the 1940s and 1950s until the adoption of natural gas. They were used for lighting, heating, and cooking, typically being supplied to households through pipe distribution systems. The gas was named after its founder, Ludwig Mond. In 1889, Ludwig Mond discovered that the combustion of coal with air and steam produced ammonia along with an extra gas, which was named
Mond gas
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and fuel technology, including the gasification of coal. In 1927 he went back to Bristol as Honorary Professor in Applied Chemistry. Travers continued his researches in cryogenics and made the first accurate temperature measurements of liquid gases. He also helped to build several experimental liquid air plants in Europe. He died in Stroud, Gloucestershire. The following is a partial list of publications: Morris Travers Morris William Travers (24 January 1872 – 25 August 1961) was an English chemist who worked with Sir William Ramsay in the discovery of xenon, neon and krypton. His work on several of the rare gases
Morris Travers
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Crankcase ventilation system A crankcase ventilation system (CVS) is a one way passage for the blow-by gases to escape in a controlled manner from the crankcase of an internal combustion engine. The blow-by gases are generated when a small but continual amount of gases (air, unburned fuel, combustion gases) leak from the combustion chamber past the piston rings, that is, "blow by" them, and the piston ring gaps to end up inside the crankcase, causing pressure to build up in there. Additional sources of blow-by that contribute to this effect are gases leaking past the turbocharger shaft, the air compressors
Crankcase ventilation system
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Inert gas An inert gas/noble gas is a gas which does not undergo chemical reactions under a set of given conditions. The noble gases often do not react with many substances, and were historically referred to as the inert gases. Inert gases are used generally to avoid unwanted chemical reactions degrading a sample. These undesirable chemical reactions are often oxidation and hydrolysis reactions with the oxygen and moisture in air. The term "inert gas" is context-dependent because several of the noble gases can be made to react under certain conditions. Purified argon and nitrogen gases are most commonly used as
Inert gas
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Compressed Gas Association (CGA) pamphlet P-1. The specific guidelines for prevention of asphyxiation due to displacement of oxygen by asphyxiant gases is covered under CGA's pamphlet SB-2, "Oxygen-Deficient Atmospheres." Specific guidelines for use of gases other than air in back-up respirators is covered in pamphlet SB-28, "Safety of Instrument Air Systems Backed Up by Gases Other Than Air." To decrease the risk of asphyxiation, there have been proposals to add warning odors to some commonly used gases such as nitrogen and argon. However, CGA has argued against this practice. They are concerned that odorizing may decrease worker vigilance, not everyone
Asphyxiant gas
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atmosphere. In 1738, Daniel Bernoulli published "Hydrodynamics", initiating the Kinetic theory of gases and established the basic laws for the theory of gases. In 1761, Joseph Black discovered that ice absorbs heat without changing its temperature when melting. In 1772, Black's student Daniel Rutherford discovered nitrogen, which he called "phlogisticated air", and together they developed the phlogiston theory. In 1777, Antoine Lavoisier discovered oxygen and developed an explanation for combustion. In 1783, in Lavoisier's essay "Reflexions sur le phlogistique", he deprecates the phlogiston theory and proposes a caloric theory. In 1804, Sir John Leslie observed that a matte black surface
Meteorology
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William Ramsay Sir William Ramsay, (; 2 October 1852 – 23 July 1916) was a Scottish chemist who discovered the noble gases and received the Nobel Prize in Chemistry in 1904 "in recognition of his services in the discovery of the inert gaseous elements in air" (along with his collaborator, John William Strutt, 3rd Baron Rayleigh, who received the Nobel Prize in Physics that same year for their discovery of argon). After the two men identified argon, Ramsay investigated other atmospheric gases. His work in isolating argon, helium, neon, krypton and xenon led to the development of a new section
William Ramsay
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William Ramsay Sir William Ramsay, (; 2 October 1852 – 23 July 1916) was a Scottish chemist who discovered the noble gases and received the Nobel Prize in Chemistry in 1904 "in recognition of his services in the discovery of the inert gaseous elements in air" (along with his collaborator, John William Strutt, 3rd Baron Rayleigh, who received the Nobel Prize in Physics that same year for their discovery of argon). After the two men identified argon, Ramsay investigated other atmospheric gases. His work in isolating argon, helium, neon, krypton and xenon led to the development of a new section
William Ramsay
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a mineral. In 1902, having accepted the evidence for the elements helium and argon, Dmitri Mendeleev included these noble gases as group 0 in his arrangement of the elements, which would later become the periodic table. Ramsay continued his search for these gases using the method of fractional distillation to separate liquid air into several components. In 1898, he discovered the elements krypton, neon, and xenon, and named them after the Greek words (, "hidden"), (, "new"), and (, "stranger"), respectively. Radon was first identified in 1898 by Friedrich Ernst Dorn, and was named "radium emanation", but was not considered
Noble gas
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that founded the British Mineralogical Society. The membership of the BMS was made up of middle-class chemists, physicians, and owners of businesses such as iron-making and instrument manufacturers which were increasingly subject to technological change. The BMS was a forerunner of the Geological Society of London. In his own research, Pepys worked on soda-water apparatus in 1798 and also researched into using mercury contacts for electrical apparatus and tubes coated in India rubber to convey gases, inventing the mercury gasometer as a result. In the field of experimental physics, he investigated several aspects of the recently discovered Voltaic electricity: his
William Haseldine Pepys
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Penzance at 23:50. It was coupled up to the Plymouth sleeping cars (which included W2437) and the ETH was turned on at 00:15. The train departed on time at 00:30 and made scheduled stops at Newton Abbot and Exeter. Nobody who saw the train noticed anything amiss, but the bags of linen were now heating up. As they smouldered they began to give off toxic gases, including carbon monoxide. Unfortunately the ventilation system drew fresh air from the vestibule, and the gases were sucked into the system and into each berth. A major fire developed and the train was stopped
Taunton sleeping car fire
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prove their presolar origin. In the 1960s, the noble gases neon and xenon were discovered to have unusual isotopic ratios in primitive meteorites. Their origin and the type of matter that contained them was a mystery. These discoveries were made by vaporizing a bulk sample of a meteorite within a mass spectrometer, an instrument that is able to count the relative abundances of the isotopes of noble gases that are trapped in the meteorite sample. During the 1970s similar mass spectrometers discovered more components of trapped xenon isotopes. Competing speculations about the origins of the xenon isotopic components were advanced,
Presolar grains
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as the lowest initial temperature of reaction. The N and CO gases evolved made up 99% of all gases evolved. Nearly all the starting materials won’t decompose until reaching temperatures of 500 °C or higher so this could be a viable option as an air bag gas generator. In a patent containing another plausible alternative to NaN driven airbags, the gas generating materials involved the use of guanidine nitrate, 5-aminotetrazole, bitetrazole dihydrate, nitroimidazole, and basic copper nitrate. It was found that these non-azide reagents allowed for a less toxic, lower combustion temperature reaction and more easily disposable air bag inflation
Airbag
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glasses on a table; there is also a trail of glass leading up to the bedroom where she discovered what would bring out this feeling of rage within her. The setting of the video is dark and features harsh coloured gases passing through the air whilst Jazmine is singing – adding the sense of anger and depression that the video is meant to bring out in the song. Other scenes feature her boyfriend's guilty conscience of what he's done – namely when he hesitantly looks himself in the mirror. US 12" vinyl<br> Australia CD single Bust Your Windows "Bust Your
Bust Your Windows
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found that the atmospheric electrification under clear weather conditions had an annual variation, and that it also varied with height. In 1785, Coulomb discovered the electrical conductivity of air. His discovery was contrary to the prevailing thought at the time, that the atmospheric gases were insulators (which they are to some extent, or at least not very good conductors when not ionized). Erman (1804) theorized that the Earth was negatively charged, and Peltier (1842) tested and confirmed Erman's idea. Several researchers contributed to the growing body of knowledge about atmospheric electrical phenomena. Francis Ronalds began observing the potential gradient and
Atmospheric electricity
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a pressure of 1/10,000 of an atmosphere. James Dewar, the scientist after whom the Dewar (vacuum flask) is named, spent much time studying activated carbon and published a paper regarding its adsorption capacity with regard to gases. In this paper, he discovered that cooling the carbon to liquid nitrogen temperatures allowed it to adsorb significant quantities of numerous air gases, among others, that could then be recollected by simply allowing the carbon to warm again and that coconut based carbon was superior for the effect. He uses oxygen as an example, wherein the activated carbon would typically adsorb the atmospheric
Activated carbon
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sustainable supply can be made by compressing atmospheric air. The air usually has moisture removed, and a small quantity of oil is added at the compressor to prevent corrosion and lubricate mechanical components. Factory-plumbed pneumatic-power users need not worry about poisonous leakage, as the gas is usually just air. Smaller or stand-alone systems can use other compressed gases that present an asphyxiation hazard, such as nitrogen—often referred to as OFN (oxygen-free nitrogen) when supplied in cylinders. Any compressed gas other than air is an asphyxiation hazard—including nitrogen, which makes up 78% of air. Compressed oxygen (approx. 21% of air) would
Pneumatics
5197281
at high temperatures): For example, the terrestrial air is primarily made up of diatomic gases (around 78% nitrogen (N) and 21% oxygen (O)), and at standard conditions it can be considered to be an ideal gas. The above value of 1.4 is highly consistent with the measured adiabatic indices for dry air within a temperature range of 0–200 °C, exhibiting a deviation of only 0.2% (see tablation above). As temperature increases, higher-energy rotational and vibrational states become accessible to molecular gases, thus increasing the number of degrees of freedom and lowering . For a real gas, both and increase with
Heat capacity ratio
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lifelong research interest has been acid-base homeostasis. With his colleagues, he was the first to demonstrate cell-pH regulation, discovered and cloned several bicarbonate transporters, elucidated the sensing of molecular carbon dioxide and bicarbonate, and introduced several experimental paradigms for studying cellular acid-base physiology. More recently, following the initial descriptions of a membrane that is impermeable to gases and a channel that is permeable to gases, Boron's group has extended its interest to understanding mechanisms of gas movement through aquaporins and Rh proteins, and the physiological significance of this movement. Boron obtained his undergraduate degree in chemistry at Saint Louis University
Walter Boron
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the need to disperse combustion flue gases to comply with governmental air pollution control regulations. The combustion flue gases inside the flue gas stacks are much hotter than the ambient outside air and therefore less dense than the ambient air. That causes the bottom of the vertical column of hot flue gas to have a lower pressure than the pressure at the bottom of a corresponding column of outside air. That higher pressure outside the chimney is the driving force that moves the required combustion air into the combustion zone and also moves the flue gas up and out of
Flue-gas stack
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the air, the polluted air is dehumidified in the cartridge (for use of the catalyst). Due to the fact that the mass of water vapor in the polluted air is much greater than the mass of harmful gases, trapping moisture from the air leads to a significantly higher increase in the mass of cartridges than the trapping gases. This is a substantial difference, and it can be used to determine whether to continue to use gas cartridges further without replacement. The cartridge was weighed, and a decision can be made based on the magnitude of increase of its mass. For
Cartridge (respirator)
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cooking declined. Once gases had been discovered and produced in modest quantities, the process of industrialisation spurred on innovation and invention of technology to produce larger quantities of these gases. Notable developments in the industrial production of gases include the electrolysis of water to produce hydrogen (in 1869) and oxygen (from 1888), the Brin process for oxygen production which was invented in the 1884, the chloralkali process to produce chlorine in 1892 and the Haber Process to produce ammonia in 1908. The development of uses in refrigeration also enabled advances in air conditioning and the liquefaction of gases. Carbon dioxide
Industrial gas
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opening a gap through which gases could leak. This phenomenon, known as "joint rotation," caused a momentary drop in air pressure. This made it possible for combustion gases to erode the O-rings. In the event of widespread erosion, a flame path could develop, causing the joint to burst—which would have destroyed the booster and the shuttle. Engineers at the Marshall Space Flight Center wrote to the manager of the Solid Rocket Booster project, George Hardy, on several occasions suggesting that Thiokol's field joint design was unacceptable. For example, one engineer suggested that joint rotation would render the secondary O-ring useless,
Space Shuttle Challenger disaster
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that provides stability over a wide range of ambient conditions and is optimal for membrane permeation. The heated air enters the membrane, which is made up of thousands of miniature hollow fibers. The walls of these fibers are semi-permeable and designed for different gases to move through them (or permeate) at different speeds. The resulting gas mixture is known as the permeate. As air flows through the hollow fibers, both oxygen and nitrogen permeate through the fiber walls. The oxygen permeates faster than the nitrogen, which produces permeate with an oxygen content greater than air. The gas that reaches the
Membrane method of gas concentration
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the hillside above. The gases are estimated to have flowed up these shafts at . Air at this speed is capable of blowing around heavy items: hot projectiles made from tunnel lining (rather like lava bombs from a volcano) were cast out over the hillside. These set much of the vegetation on fire, and caused the closure of the A6033 road. In the cleanup operation afterwards, small globules of metal were found on the ground surrounding shaft 9; these had been melted from the tanker walls, swept up with the exhaust gases, and dropped out onto the grass around the
Summit Tunnel fire
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College, where he began to work with Sir William Ramsay. Travers helped Ramsay to determine the properties of the newly discovered gases argon and helium. They also heated minerals and meteorites in the search for further gases, but found none. Then in 1898 they obtained a large quantity of liquid air and subjected it to fractional distillation. Spectral analysis of the least volatile fraction revealed the presence of krypton. They examined the argon fraction for a constituent of lower boiling point, and discovered neon. Finally xenon, occurring as an even less volatile companion to krypton, was identified spectroscopically. He knew
Morris Travers
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much of the current knowledge of the properties of airs. Boerhaave is also credited with adding to the world of chemical thermometry through his work with Daniel Fahrenheit, also discussed in "Elementa Chimiae." Henry Cavendish, despite not being the first to replace water in the trough with mercury, he was among the first to observe that fixed air was insoluble over mercury and therefore could be collected more efficiently using the adapted instrument. He also characterized fixed air (CO) and inflammable air (H). Inflammable air was one of the first gases isolated and discovered using the pneumatic trough. However, he
Pneumatic chemistry
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be used to measure the amount of radiation exposure, so if the temperature at which the fulgurite was formed is known, one could determine the relative age of the mineral by examining the doses of radiation involved in the process. Fulgurite also contains air bubbles. Given that the formation of fulgurite generally takes only about one second, and that the process involved in the creation of fulgurite involves several chemical reactions, it is relatively easy to trap various gases, such as CO2, within the air bubbles of these minerals. These gases can be trapped for millions of years. Studies have
Paleolightning
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Neon Neon is a chemical element with symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypton and xenon) in 1898 as one of the three residual rare inert elements remaining in dry air, after nitrogen, oxygen, argon and carbon dioxide were removed. Neon was the second of these three rare gases to be discovered and was immediately recognized as a new element from its bright red emission spectrum. The name neon is derived from
Neon
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Russell Group, and is part of UCL Partners, the world's largest academic health science centre, and the "golden triangle" of research-intensive English universities. UCL alumni include the 'Father of the Nation' of each of India, Kenya and Mauritius, the founders of Ghana, modern Japan and Nigeria, the inventor of the telephone, and one of the co-discoverers of the structure of DNA. UCL academics discovered five of the naturally occurring noble gases, discovered hormones, invented the vacuum tube, and made several foundational advances in modern statistics. As of 2017, 33 Nobel Prize winners and 3 Fields medalists have been affiliated with
University College London
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in his honor. Chladni discovered Chladni's law, a simple algebraic relation for approximating the modal frequencies of the free oscillations of plates and other bodies. Chladni estimated sound velocities in different gases by placing those gases in an organ pipe and measuring the characteristics of the sounds that emerged when the pipe was played. This built on work on measuring the speed of sound in air that Pierre Gassendi began in 1635. Chladni died on April 3, 1827, in Breslau, Lower Silesia, then part of the Kingdom of Prussia and today the city of Wrocław in southwestern Poland. Ernst Chladni
Ernst Chladni
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the air pressure, with excess air escaping up the muck tube. The pressurized air flow must be constant to ensure regular air changes for the workers and prevent excessive inflow of mud or water at the base of the caisson. To install a caisson in place, it is brought down through soft mud until a suitable foundation material is encountered. While bedrock is preferred, a stable, hard mud is sometimes used when bedrock is too deep. Construction workers who leave the pressurized environment of the caisson must decompress at a rate that allows symptom-free release of inert gases dissolved in
Caisson (engineering)
5759192
Personal Egress Air Pack Personal Egress Air Packs, or PEAPs, were devices on board a Space Shuttle which provided crew members with approximately six minutes of breathable air in the case of a mishap while the vehicle was still located on the ground. PEAPs did not provide pressurized air, meaning that they were only intended to be used should the air inside the shuttle cabin become unbreathable by way of noxious gases. The devices gained notoriety due to the "Challenger" disaster. After the recovery of the vehicle cockpit, it was discovered that three of the crew PEAPs were activated: those
Personal Egress Air Pack
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gases oxygen, nitrogen and argon, all of which are manufactured in Linde's air separation plants. The product portfolio includes hydrogen, acetylene, carbon monoxide, carbon dioxide, shielding gases for welding applications, noble gases and specialty gases. In addition, Linde develops and distributes procedures and systems for gas applications in several technological application centres. Linde is the world's largest supplier of welding and safety products. Linde Healthcare provides pharmaceutical and medical gas products and services for healthcare professionals. Linde Healthcare is present in 70 countries. Pharmaceutical and medical gases are used in the diagnosis or treatment of a number of clinical conditions.
Linde plc
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Lighter than air Lighter than air refers to materials (usually gases) that are buoyant in air because they have average densities lower than that of air. Dry air has a density of about 1.29 g/L (gram per liter) at standard conditions for temperature and pressure (STP) and an average molecular mass of 28.97 g/mol. Some of these gases are used as lifting gases in lighter-than-air aircraft, which include free balloons, moored balloons, and airships. Heavier-than-air aircraft include airplanes, gliders and helicopters. Hot air is frequently used in recreational ballooning. Hot air is lighter than air at ambient temperature, to a
Lighter than air
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Lighter than air Lighter than air refers to materials (usually gases) that are buoyant in air because they have average densities lower than that of air. Dry air has a density of about 1.29 g/L (gram per liter) at standard conditions for temperature and pressure (STP) and an average molecular mass of 28.97 g/mol. Some of these gases are used as lifting gases in lighter-than-air aircraft, which include free balloons, moored balloons, and airships. Heavier-than-air aircraft include airplanes, gliders and helicopters. Hot air is frequently used in recreational ballooning. Hot air is lighter than air at ambient temperature, to a
Lighter than air
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in London. Neon was discovered when Ramsay chilled a sample of air until it became a liquid, then warmed the liquid and captured the gases as they boiled off. The gases nitrogen, oxygen, and argon had been identified, but the remaining gases were isolated in roughly their order of abundance, in a six-week period beginning at the end of May 1898. First to be identified was krypton. The next, after krypton had been removed, was a gas which gave a brilliant red light under spectroscopic discharge. This gas, identified in June, was named "neon", the Greek analogue of "novum" (new),
Neon
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Air Gases. BOC also acquired Praxair's operations in Poland. In November 2003, BOC Group announced that it would complete the sale of Afrox Healthcare - a hospital and managed health care group operating in South Africa - to a consortium led by Black Economic Empowerment investors. The BOC Group's total revenues in 2005, including its share of joint ventures and associate companies, were £4.6 billion and was then the second largest industrial gas supplier in the world. Industrial gases business made up for more than 80% of sales. The group was getting nearly one-third of its revenues from Asia Pacific;
The BOC Group
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certify cartridges intended for cleaning air of various gaseous contaminants. The codes are covered by EN14387, additionally particulate codes P1, P2 and P3 are used. For example, A1P2 is the code for commonly used filters in industry and agriculture that provide protection against A type gases and commonly occurring particulates. Cartridges AX, SX and NOP3 not distinguish on the sorption capacity (as in the US) when they are classified and certified. If the cartridge is designed to protect from several different types of harmful gases, in the designation contains the list of designations for specific types of perceived harmful gases,
Cartridge (respirator)
3771877
source of emissions of volatile organic compounds (VOCs), a group of chemicals that contribute to the formation of ground-level ozone (smog). The combustion of fossil fuels produces greenhouse gases and other air pollutants as by-products. Pollutants include nitrogen oxides, sulphur dioxide, volatile organic compounds and heavy metals. Researchers have discovered that the petrochemical industry can produce ground-level ozone pollution at higher amounts in winter than in summer.. The greenhouse gases due to fossil fuels drive global warming. Already in 1959, at a symposium organised by the American Petroleum Institute for the centennial of the American oil industry, the physicist Edward
Petroleum industry
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gas emissions can be done in many ways. Many industries that emit these gases can capture or recycle them. These same industries can also invest in more advanced technology that will not produce these gases. A reduction of leakage within power grids and motor vehicles will also decrease the emissions of fluorinated gases. There are also many air conditioning systems that emit fluorinated gases, thus an update in technology would decrease these emissions. There are many simple changes that can be made to the everyday lifestyle of a person that would reduce their GHG footprint. Reducing energy consumption within a
Greenhouse gas footprint
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2015. Greenhouse gas<br> Montreal Protocol<br> Refrigerant Fluorinated gases Fluorinated gases (F-gases) are man-made gases that can stay in the atmosphere for centuries and contribute to a global greenhouse effect. There are four types: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF) and nitrogen trifluoride (NF). The most common F-gases are hydrofluorocarbons (HFCs), which contain hydrogen, fluorine, and carbon. They are used in a multitude of applications including commercial refrigeration, industrial refrigeration, air-conditioning systems, heat pump equipment, and as blowing agents for foams, fire extinguishants, aerosol propellants, and solvents. Perfluorocarbons (PFCs) are the compounds consisting of fluorine and carbon. They are widely
Fluorinated gases
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Fluorinated gases Fluorinated gases (F-gases) are man-made gases that can stay in the atmosphere for centuries and contribute to a global greenhouse effect. There are four types: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF) and nitrogen trifluoride (NF). The most common F-gases are hydrofluorocarbons (HFCs), which contain hydrogen, fluorine, and carbon. They are used in a multitude of applications including commercial refrigeration, industrial refrigeration, air-conditioning systems, heat pump equipment, and as blowing agents for foams, fire extinguishants, aerosol propellants, and solvents. Perfluorocarbons (PFCs) are the compounds consisting of fluorine and carbon. They are widely used in the electronics, cosmetics, and
Fluorinated gases
6189929
for beer kegs, welding gases and welding equipment, LPG and medical oxygen. Retail sales of small scale gas supply are not confined to just the industrial gas companies or their agents. A wide variety of hand-carried small gas containers, which may be called cylinders, bottles, cartridges, capsules or canisters are available to supply LPG, butane, propane, carbon dioxide or nitrous oxide. Examples are Whipped-cream chargers, powerlets, campingaz and sodastream. The first gas from the natural environment used by humans was almost certainly air when it was discovered that blowing on or fanning a fire made it burn brighter. Humans also
Industrial gas
15959737
an insecticide. This would make the classification of the compound as secret disadvantageous for commercial firms . Around the beginning of the Second World War, several independent studies were conducted by the military and pharmaceutical companies. It was discovered that TEPP is an inhibitor of cholinesterases. Schrader referred to the studies by Eberhard Gross, who was the first to recognize the mechanism of action for TEPP in 1939. More experiments were conducted by other pharmacologists such as Hans Gremels, who was able to confirm Gross’s work a year later. Gremels was also involved in the development of nerve gases at
Tetraethyl pyrophosphate
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than in liquids, and faster in liquids than in gases, because the solids are more difficult to compress than liquids, while liquids in turn are more difficult to compress than gases. Some textbooks mistakenly state that the speed of sound increases with density. This notion is illustrated by presenting data for three materials, such as air, water and steel, which also have vastly different compressibility, more which making up for the density differences. An illustrative example of the two effects is that sound travels only 4.3 times faster in water than air, despite enormous differences in compressibility of the two
Speed of sound
4250079
inserting bricks into the hearth to make the side walls angled, and they added a choke to the chimney to create a circulation of air inside the chimney. In the unmodified chimney, smoke rises up the chimney propelled only by buoyancy -- the heated gases from the fireplace being lighter than the surrounding air. This is especially ineffective when the fire is first lit and the temperature and density of the smoke are closer to the ambient air. Thanks to the discontinuity produced by Rumford's brick "smoke shelf", the flow of smoke gases up the chimney became detached from the
Rumford fireplace
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must come out" principle. Consider a closed system first. Imagine that we place a mouse into an air-tight container. The air sealed in the container initially contains the same composition and proportions of gases that were present in the room: 20.95% O, 0.04% CO, water vapor (the exact amount depends on air temperature, see dew point), 78% (approximately) N, 0.93% argon and a variety of trace gases making up the rest (see Earth's atmosphere). As time passes, the mouse in the chamber produces CO and water vapor, but extracts O from the air in proportion to its metabolic demands. Therefore,
Respirometry
6189937
gases were developed many more gases came to be sold in cylinders without the need for a gas generator. Air separation plants refine air in a separation process and so allow the bulk production of nitrogen and argon in addition to oxygen - these three are often also produced as cryogenic liquid. To achieve the required low distillation temperatures, an Air Separation Unit (ASU) uses a refrigeration cycle that operates by means of the Joule–Thomson effect. In addition to the main air gases, air separation is also the only practical source for production of the rare noble gases neon, krypton
Industrial gas
9716359
public health and welfare. 2) The 'Cause or Contribute Finding,' in which the Administrator found that the combined greenhouse gas emissions from new motor vehicles and motor vehicle engines contribute to the atmospheric concentrations of these key greenhouse gases and hence to the threat of climate change. The EPA issued these endangerment findings in response to the 2007 supreme court case Massachusetts v. EPA, when the court determined that greenhouse gases are air pollutants according to the Clean Air Act. The court made the decision that the EPA must determine whether greenhouse gas emissions from new motor vehicles "cause or
Criteria air pollutants
6189931
of sulfur inside empty wine vessels would keep them fresh and prevent them gaining a vinegar smell. Early understanding consisted of empirical evidence and the protoscience of alchemy; however with the advent of scientific method and the science of chemistry, these gases became positively identified and understood. The history of chemistry tells us that a number of gases were identified and either discovered or first made in relatively pure form during the Industrial Revolution of the 18th and 19th centuries by notable chemists in their laboratories. The timeline of attributed discovery for various gases are carbon dioxide (1754), hydrogen (1766),
Industrial gas
4550161
the relationship can be used to estimate tropospheric residence-times of gases. Trace gas The most abundant gases in the atmosphere are nitrogen (78.1%), oxygen (20.9%), and argon (0.934%). Combined, oxygen, argon, and nitrogen make up 99.934% of the gases in the atmosphere (not including water vapor). The other gases that are not part of the 99.934% of the atmosphere are called trace gases. The abundance of a trace gas can range from a few parts per trillion (ppt) by volume to several hundred parts per million by volume (ppmv). When a trace gas is added into the atmosphere, that process
Trace gas
5490533
this formed an ‘S’ shape so the gases made three passes through the water. This ‘S’ shaped tube was also tapered causing the gases to speed up as they cooled down. In practice this tube is almost impossible to clean. The resulting boiler was the shape of a hammer and was required to be fitted to the frame before the footplate, cylinders or blower could be added. The boiler used a ‘Forced Draught’ provided by a mechanical blower (the triangular structure on the right in the illustration). This forced air along a pipe and into the sealed ashpan (below the
Novelty (locomotive)
3439421
Danish mathematician and scientist Ludvig Lorenz, who published it in 1869, and the Dutch physicist Hendrik Lorentz, who discovered it independently in 1878. The most general form of the Lorentz–Lorenz equation is where formula_11 is the refractive index, formula_4 is the number of molecules per unit volume, and formula_13 is the mean polarizability. This equation is approximately valid for homogeneous solids as well as liquids and gases. When the square of the refractive index is formula_14, as it is for many gases, the equation reduces to: or simply This applies to gases at ordinary pressures. The refractive index formula_11 of
Clausius–Mossotti relation
4686987
dust and mine gases such as methane, carbon dioxide, depending on the geology of the coal. Return air is extracted by ventilation fans mounted on the surface. Other ventilation methods can be used where intake air also passes the main gate and into a bleeder or back return road reducing gas emissions from the goaf on to the face, or intake air travels up the tail gate and across the face in the same direction as the face chain in a homotropal system. To avoid spontaneous combustion of coal in the goaf area, gases may be allowed to build up
Longwall mining
6135909
quantity of air admitted to the furnace and direct some of the air to the Primary Air (PA) Fans. There were also two large Induced Draft (ID) Fans on each unit. These drew the hot gases from the Boiler, through the Air Heater where the heat is transferred to the incoming combustion air. The gases were then exhausted up the chimney. The exhaust flow of these fans was also controlled by dampers in the ducting. Working in tandem the Draught plant ensured the boiler was always under a slight vacuum. This created a draw of combustion air into the boiler
Cockenzie power station
3231165
lifting gas from escaping. Common lifting gases have included hydrogen, coal gas and helium. When heated, air expands. This lowers its density and creates lift. Small hot air balloons or lanterns have been flown in China since ancient times. The first modern man-lifting aerostat, made by the Montgolfier brothers, was a hot air balloon. Most early balloons however were gas balloons. Interest in the sport of hot air ballooning reawoke in the second half of the twentieth century and even some hot-air airships have been flown. Hydrogen is the lightest of all gases and a manned hydrogen balloon was flown
Aerostat
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NGC 4889 NGC 4889 (also known as Coma B) is an E4 supergiant elliptical galaxy. It was discovered in 1785 by the British astronomer Frederick William Herschel I, who catalogued it as a bright, nebulous patch. The brightest galaxy within the northern Coma Cluster, it is located at a median distance of 94 million parsecs (308 million light years) from Earth. At the core of the galaxy is a supermassive black hole that heats the intracluster medium through the action of friction from infalling gases and dust. The gamma ray bursts from the galaxy extend out to several million light
NGC 4889
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Lifting gas Because of Archimedes' principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air (about 1.29 kg/m, 1.29 g/L). Only certain lighter than air gases are suitable as lifting gases. Heated atmospheric air is frequently used in recreational ballooning. According to the Ideal gas law, an amount of gas (and also a mixture of gases such as air) expands as it is heated. As a result, a certain volume of gas has a lower weight as the temperature is higher. The average temperature of air in a hot air balloon
Lifting gas
12187740
consumer items and only gradually spread in use. The stove is connected by ventilating stove pipe to a suitable flue, which will fill with hot combustion gases once the fuel is ignited. The chimney or flue gases must be hotter than the outside temperature to ensure combustion gases are drawn out of the fire chamber and up the chimney. Keeping the air flowing correctly through a wood-burning stove is essential for safe and efficient operation of the stove. Fresh air needs to enter the firebox to provide oxygen for the fire; as the fire burns, the smoke must be allowed
Wood-burning stove
4550155
Trace gas The most abundant gases in the atmosphere are nitrogen (78.1%), oxygen (20.9%), and argon (0.934%). Combined, oxygen, argon, and nitrogen make up 99.934% of the gases in the atmosphere (not including water vapor). The other gases that are not part of the 99.934% of the atmosphere are called trace gases. The abundance of a trace gas can range from a few parts per trillion (ppt) by volume to several hundred parts per million by volume (ppmv). When a trace gas is added into the atmosphere, that process is called a "source". There are two possible types of sources
Trace gas
2420032
smoldered for hours until it found fresh oxygen and burst into a fireball that burst into the casino, and was fed by other combustibles. Due to faulty smoke dampers within the ventilation duct network, the toxic fumes circulated throughout the hotel's air conditioning system, accelerating the spread of the poisonous gases. The elevator shafts were located above the restaurant and casino and aided the spreading of smoke, and guests who discovered fire doors in some stairwells automatically locked, propped them open allowing for more smoke to spread. The casino and restaurants were not protected by a fire sprinkler system because
MGM Grand fire
18317991
greenhouse gases, thereby reducing pollution. According to McCabe, there was power created from the gyroscopic precession and he explored how to channel that power. McCabe's theory was that a spinning wheel shaped like a disc put into gyroscopic motion by a certain amount of torque could, in turn, produce an exponential amount of torque. McCabe discovered that when he used an air compressor to put 1.2 pounds per square inch (PSI) of torque into his gyroscopic wheel, it created 1,200 PSI of torque out. He also discovered the in-to-out relationship grew in an exponential manner and that by adding a
Francis J. McCabe
585333
organic chemistry and on gases. In 1887 he succeeded Alexander Williamson as the chair of Chemistry at University College London (UCL). It was here at UCL that his most celebrated discoveries were made. As early as 1885–1890 he published several notable papers on the oxides of nitrogen, developing the skills that he needed for his subsequent work. On the evening of 19 April 1894 Ramsay attended a lecture given by Lord Rayleigh. Rayleigh had noticed a discrepancy between the density of nitrogen made by chemical synthesis and nitrogen isolated from the air by removal of the other known components. After
William Ramsay
15417861
Section 202(a)(1) of the CAA requires the Administrator of the EPA to establish standards "applicable to the emission of any "air pollutant" from…new motor vehicles or new motor vehicle engines, which in [her] judgment "cause, or contribute" to, air pollution which may reasonably be anticipated to "endanger" public health or welfare" (emphasis added). On October 20, 1999, the International Center for Technology Assessment (ICTA) and several other parties (petitioners) petitioned the EPA to regulate greenhouse gases from new motor vehicles under the Act. The petitioners argued that carbon dioxide (CO), methane (CH), nitrous oxide (NO), and hydrofluorocarbons meet the definition
Regulation of greenhouse gases under the Clean Air Act
4465526
made between potassium and sodium. Sodium was first isolated by Davy in the same year by passing an electric current through molten sodium hydroxide (NaOH). When Davy heard that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, he tried it himself. Davy was successful, and discovered calcium in 1808 by electrolyzing a mixture of lime and mercuric oxide. He worked with electrolysis throughout his life and, in 1808, he isolated magnesium, strontium and barium. Davy also experimented with gases by inhaling them. This experimental procedure nearly proved fatal on several occasions, but led to the discovery of
History of chemistry
2637261
prosecuted and sent to jail several people presenting themselves as medical doctors and selling ozone therapy products as a medical cure or operating medical clinics using ozone therapy for healing human illness. Arrests following similar activity have been made in other countries as well. At least 10 deaths have been related to ozone therapy or its lack of usefulness, in nine cases there had been investigation and in eight it was discovered that the practitioners had used false credentials. Ozone therapy consists of the introduction of ozone into the body via various methods, usually involving its mixture with various gases
Ozone therapy
3499854
the vicinity of the muzzle by the hot propellant gases and the chemical reactions that follow as the gases mix with the surrounding air. Before projectiles exit a slight pre-flash may occur from gases leaking past the projectiles. Following muzzle exit the heat of gases is usually sufficient to emit visible radiation – the primary flash. The gases expand but as they pass through the Mach disc they are re-compressed to produce an intermediate flash. Hot combustible gases (e.g. hydrogen and carbon-monoxide) may follow when they mix with oxygen in the surrounding air to produce the secondary flash, the brightest.
Smokeless powder
97994
apart. Due to the air space between the hulls, there is also a potential problem with volatile gases seeping out through worn areas of the internal hull, increasing the risk of an explosion. Although several international conventions against pollution are in place, as of 2003 there was still no formal body setting international mandatory standards, although the International Safety Guide for Oil Tankers and Terminals (ISGOTT) does provide guidelines giving advice on optimum use and safety, such as recommending that ballast tanks are not entered while loaded with cargo, and that weekly samples are made of the atmosphere inside for
Double-hulled tanker
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mass flow meter (also called thermal dispersion or thermal displacement flowmeter) technology is used for compressed air, nitrogen, helium, argon, oxygen, and natural gas. In fact, most gases can be measured as long as they are fairly clean and non-corrosive. For more aggressive gases, the meter may be made out of special alloys (e.g. Hastelloy), and pre-drying the gas also helps to minimize corrosion. Today, thermal mass flow meters are used to measure the flow of gases in a growing range of applications, such as chemical reactions or thermal transfer applications that are difficult for other flow metering technologies. This
Flow measurement
280089
in 1895, Lord Rayleigh discovered that samples of nitrogen from the air were of a different density than nitrogen resulting from chemical reactions. Along with Scottish scientist William Ramsay at University College, London, Lord Rayleigh theorized that the nitrogen extracted from air was mixed with another gas, leading to an experiment that successfully isolated a new element, argon, from the Greek word (, "idle" or "lazy"). With this discovery, they realized an entire class of gases was missing from the periodic table. During his search for argon, Ramsay also managed to isolate helium for the first time while heating cleveite,
Noble gas
19187308
star, gases condense into raindrop like particles made up of sand and iron which fall onto the interior. Researchers also determined that the object's temperature ranges from 1,100 to 1,300 degrees Fahrenheit (600 to 700 degrees Celsius). 2MASS J22282889-4310262 2MASS J22282889-4310262 is a brown dwarf discovered by The Hubble Space Telescope and The Spitzer Space Telescope in 2013. Through the uses of the Hubble and Spitzer, NASA astronomers were able to develop the most detailed 'weather map' for the brown dwarf utilizing different wavelengths of infrared light to show changing light patterns and different layers of material in the windstorms
2MASS J22282889-4310262
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to improve the perception of objects by 79.5%. Safety lamp A safety lamp is any of several types of lamp that provides illumination in coal mines and is designed to operate in air that may contain coal dust or gases both of which are potentially flammable or explosive. Until the development of effective electric lamps in the early 1900s miners used flame lamps to provide illumination. Open flame lamps could ignite flammable gases which collected in mines, causing explosions and so safety lamps were developed to enclose the flame and prevent it from igniting the surrounding atmosphere. Flame safety lamps
Safety lamp
5721738
Safety lamp A safety lamp is any of several types of lamp that provides illumination in coal mines and is designed to operate in air that may contain coal dust or gases both of which are potentially flammable or explosive. Until the development of effective electric lamps in the early 1900s miners used flame lamps to provide illumination. Open flame lamps could ignite flammable gases which collected in mines, causing explosions and so safety lamps were developed to enclose the flame and prevent it from igniting the surrounding atmosphere. Flame safety lamps have been replaced in mining with sealed explosion-proof
Safety lamp
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of an "air pollutant" under section 302(g) of the Act, and that statements made by the EPA, other federal agencies, and the United Nations Intergovernmental Panel on Climate Change (IPCC) amounted to a finding that these pollutants are reasonably anticipated to endanger public health and welfare. Based on these factors, the petitioners asserted that EPA had a mandatory duty to regulate greenhouse gases under section 202 of the Act, and asked the agency to carry out that duty. On September 8, 2003, EPA denied the ICTA petition on the ground that it did not have authority under the CAA to
Regulation of greenhouse gases under the Clean Air Act
1608042
around the blast pipe orifice, containing several small steam nozzles directed up the chimney. These nozzles are fed with steam directly from the boiler, controlled by the blower valve. When the regulator is open, the blower valve is closed; when the driver intends to close the regulator, he will first open the blower valve. It is important that the blower be opened before the regulator is closed, since without draught on the fire, there may be backdraught – where atmospheric air blows down the chimney, causing the flow of hot gases through the boiler tubes to be reversed, with the
Steam locomotive
7691063
other living organisms such as food crops, or damage the natural environment or built environment. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems. Pollution of breathable air is a central problem in the management of the global commons. Pollutants can be in the form of solid particles, liquid droplets, or gases and may be natural or man-made. Although controversial and limited in scope by methods of enforcement, in several parts of the world the polluter pays principle, which makes the party responsible for producing
Global commons
18858487
may exceed the Permissible Exposure Limit PEL. Therefore, the service life of the cartridges is limited. The bond strength between the captured molecule and sorbent has a small, and the molecule is able to separate from the sorbent and get into the air again. The ability of the sorbent to capture the gases depends on: the properties of the gases and their concentrations, the air temperature, the air relative humidity, the rate of air consumed by the employee, and many other factors. Activated carbon can be saturated with chemicals that make more stronger ties with molecules of trapped gases -
Cartridge (respirator)
20150255
capacity (27 000 m3/h) insures a residual pressure ranged between 1 and 100 Pa. Different working gases can be used like Argon, nitrogen, CO2, CH4 Air, allowing the simulation of several planetary entry conditions like earth (80%N2-20%O2), Mars (97%CO2-3%N2) or Titan (99% N2-1% CH4). The advantages of the home-made designed plasma source can be found in the stability of the plasma flow, the high specific enthalpy, up to 50 MJ/kg due to the low mass flow rate and the low rate of contamination which could provides from the erosion of the cathode. Various types of diagnostics are associated to the
PHEDRA (Arc-jet) high enthalpy wind tunnel
1846835
inert gases due to their high natural abundance (78.2% N, 1% Ar in air) and low relative cost. Unlike noble gases, an inert gas is not necessarily elemental and is often a compound gas. Like the noble gases the tendency for non-reactivity is due to the valence, the outermost electron shell, being complete in all the inert gases. This is a tendency, not a rule, as noble gases and other "inert" gases can react to form compounds. The inert gases are obtained by fractional distillation of air, with the exception of helium which is separated from a few natural gas
Inert gas
13528556
recycled gases, which cause decomposition of the rock. Recycled gases enter the retort from the bottom. Gases are heated on the lower part of retort by descended spent shale. On their way up, gases move through the combustion zone, where air and dilution gases are injected causing combustion of gases and carbonaceous residue of spent shale (char). The heat from combustion brings the temperature in the retorting zone above of the burning zone to the necessary level for retorting. The incoming raw oil shale cool oil vapors and gases, which then leave the top of the retort as a mist.
Gas combustion retort process
9394256
paste made of oil and ground up fish scales or mother-of-pearl for their iridescence. The coated nuclei are then dried and polished by hand to remove imperfections such as bumps and blemishes. This coating process is repeated (around 30 times) until a multitude of fine layers is formed over the nuclei, building up the density and color uniformity. To assure durability, the formed, blended multiple layers are subjected to various gases and solutions that make them impervious to discoloration, chipping and peeling. Majorica pearls are different from oyster pearls in several respects. Majorica pearls are man-made in a factory under
Majorica pearl
4145866
Kites were the first form of man-made flying objects, and early records suggest that kites were around before 200 BC in China. Leonardo da Vinci's dream of flight found expression in several designs, but he did not attempt to demonstrate flight by literally constructing them. During the 17th and 18th century, when scientists began analysing the Earth's atmosphere, gases such as hydrogen were discovered which in turn led to the invention of hydrogen balloons. Various theories in mechanics by physicists during the same period of time—notably fluid dynamics and Newton's laws of motion—led to the foundation of modern aerodynamics. Tethered
History of transport
61393
elements, which was then developed into the modern periodic table of elements in the 1860s by Dmitri Mendeleev and independently by several other scientists including Julius Lothar Meyer. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table. At the turn of the twentieth century the theoretical underpinnings of chemistry were finally understood due to a series of remarkable discoveries that succeeded in probing and discovering the very nature of the internal structure of atoms. In 1897,
Chemistry
3443369
but is only 60 percent that of diesel and 70 percent that of gasoline. Experiments on the properties of gases started early in the seventeenth century. By the middle of the seventeenth century Robert Boyle had derived the inverse relationship between the pressure and the volume of gases. About the same time, Guillaume Amontons started looking into temperature effects on gas. Various gas experiments continued for the next 200 years. During that time there were efforts to liquefy gases. Many new facts on the nature of gases had been discovered. For example, early in the nineteenth century Cagniard de la
Liquefied natural gas
5926826
twice in two chambers. While expanding, the gas has to do work as it is led through an expansion turbine. The gas is not yet liquid, since that would destroy the turbine. Commercial air liquefication plants bypass this problem by expanding the air at supercritical pressures. Final liquefaction takes place by isenthalpic expansion in a thermal expansion valve. Liquefaction of gases Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple
Liquefaction of gases
17707527
gases from leaking into the crankcase or the oil into the combustion chamber. A ventilation system drives the small amount of gas that escape past the pistons during normal operation (the blow-by gases) out of the crankcase so that it does not accumulate contaminating the oil and creating corrosion. In two-stroke gasoline engines the crankcase is part of the air–fuel path and due to the continuous flow of it they do not need a separate crankcase ventilation system. The cylinder head is attached to the engine block by numerous bolts or studs. It has several functions. The cylinder head seals
Internal combustion engine
18124211
about global warming, Milkey initiated the case Massachusetts v. Environmental Protection Agency, joining with eleven other states to argue that the George W. Bush Administration should regulate carbon emissions under the Clean Air Act. The case made its way to the Supreme Court, with Milkey himself arguing before the court that carbon dioxide and other greenhouse gases should be regulated by the EPA as air pollutants. Massachusetts prevailed in a 5-4 decision. The EPA would ultimately begin regulating greenhouse gases under the Obama Administration. Milkey was appointed to the Massachusetts Appeals Court by Governor Deval Patrick, joining the court in
James Milkey
10137534
be taken to distinguish between several forms of relevant diseases. According to the World Health Organization (WHO), these may defined as; asbestosis, "lung cancer", and "Peritoneal Mesothelioma" (generally a very rare form of cancer, when more widespread it is almost always associated with prolonged exposure to asbestos). Biological sources of air pollution are also found indoors, as gases and airborne particulates. Pets produce dander, people produce dust from minute skin flakes and decomposed hair, dust mites in bedding, carpeting and furniture produce enzymes and micrometre-sized fecal droppings, inhabitants emit methane, mold forms on walls and generates mycotoxins and spores, air
Air pollution
11753173
while some of the mechanical properties of gases were understood, as typified by Robert Boyle's experiments and the development of the air pump, their chemical properties were not. Gases were regarded in keeping the Aristotelean tradition of four elements as being air, one of the four fundamental elements. The different sorts of airs, such as putrid airs or inflammable air, were looked upon as atmospheric air with some impurities, much like muddied water. After Joseph Black realized that carbon dioxide was in fact a different sort of gas altogether from atmospheric air, other gases were identified, including hydrogen by Henry
History of manufactured fuel gases
13129759
in hydraulic applications and alternative compressed gas applications (Oxy-acetylene welding and cutting, fuel gases, NSF C-2 food-contact, etc...), though perhaps not as frequently. In many instances the name is the manufacturer who originated or popularized a particular design. Summary table of cross-compatible "meta" fitting designs, specifications, or profiles, alpha-sorted by common fitting name. "Table 3 should be incorporated into the other tables above" Air-line fitting This article is a compendium of hand-operable air-line fittings, typically of quick-disconnect type, used for pneumatics and other compressed air purposes including breathable air (a subset of breathing gases). For breathable air applications such as
Air-line fitting
2973019
Mortars). Le Chatelier in 1901 attempted the direct combination of the two gases nitrogen and hydrogen at a pressure of 200 atm and 600 °C in presence of metallic iron. The mixture of gases was forced by an air compressor into a steel Berthelot bomb, where they and the reduced iron catalyst were heated by a platinum spiral. A terrific explosion occurred which nearly killed an assistant. Le Chatelier found that the explosion was due to the presence of air in the apparatus used. And thus it was left for Haber to succeed where several noted French chemists, including Thenard,
Henry Louis Le Chatelier