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Chemical warfare Moving large numbers of heavy gas cylinders to the front-line positions from where the gas would be released was a lengthy and difficult logistical task. Stockpiles of cylinders had to be stored at the front line, posing a great risk if hit by artillery shells. Gas delivery depended greatly on wind spe... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Second, gas shells could be delivered without warning, especially the clear, nearly odorless phosgenethere are numerous accounts of gas shells, landing with a "plop" rather than exploding, being initially dismissed as dud high explosive or shrapnel shells, giving the gas time to work before the soldier... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Most thermal dissemination devices consist of a bomb or projectile shell that contains a chemical agent and a central "burster" charge; when the burster detonates, the agent is expelled laterally. Thermal dissemination devices, though common, are not particularly efficient. First, a percentage of the a... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare This technique eliminates many of the limitations of thermal dissemination by eliminating the flashing effect and theoretically allowing precise control of particle size. In actuality, the altitude of dissemination, wind direction and velocity, and the direction and velocity of the aircraft greatly inf... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare These include a wide range of intelligence disciplines, such as economic analysis of exports of dual-use chemicals and equipment, human intelligence (HUMINT) such as diplomatic, refugee, and agent reports; photography from satellites, aircraft and drones (IMINT); examination of captured equipment (TECH... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare If, for example, the captain of a US Navy ship believes there is a serious threat of chemical, biological, or radiological attack, the crew may be ordered to set Circle William, which means closing all openings to outside air, running breathing air through filters, and possibly starting a system that c... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Some "nonpersistent" agents, including most pulmonary agents (chlorine, phosgene, and so on), blood gases, and nonpersistent nerve gases (e.g., GB), will dissipate from open areas, although powerful exhaust fans may be needed to clear out buildings where they have accumulated. In some cases, it might b... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare For decontaminating equipment and buildings exposed to persistent agents, such as blister agents, VX or other agents made persistent by mixing with a thickener, special equipment and materials might be needed. Some type of neutralizing agent will be needed; e.g. in the form of a spraying device with ne... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Before 1915 the use of poisonous chemicals in battle was typically the result of local initiative, and not the result of an active government chemical weapons program. There are many reports of the isolated use of chemical agents in individual battles or sieges, but there was no true tradition of their... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare In a letter dated April 8, 1997, then Halliburton-CEO Cheney told Sen. Jesse Helms, the chairman of the Senate Foreign Relations Committee, that it would be a mistake for America to join the Convention. "Those nations most likely to comply with the Chemical Weapons Convention are not likely to ever con... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare By 2005, from among six nations that had declared their possession of chemical weapons, India was the only country to meet its deadline for chemical weapons destruction and for inspection of its facilities by the Organisation for the Prohibition of Chemical Weapons. By 2006, India had destroyed more th... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare The weapons are classified as abandoned chemical weapons under the Chemical Weapons Convention and from September 2010 Japan has started their destruction in Nanjing using mobile destruction facilities in order to do so. Russia signed into the Chemical Weapons Convention on January 13, 1993 and ratifie... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare As of July 2011, Russia has destroyed 48 percent (18,241 tons) of its stockpile at destruction facilities located in Gorny (Saratov Oblast) and Kambarka (Udmurt Republic) - where operations have finished - and Schuch'ye (Kurgan Oblast), Maradykovsky (Kirov Oblast), Leonidovka (Penza Oblast) whilst inst... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare ratified the Geneva Protocol which banned the use of chemical and biological weapons on January 22, 1975. In 1989 and 1990, the U.S. and the Soviet Union entered an agreement to both end their chemical weapons programs, including binary weapons. In April 1997, the United States ratified the Chemical We... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Bush committed the United States to destroying all of its chemical weapons and renounced the right to chemical weapon retaliation. In 1993, the United States signed the Chemical Weapons Treaty, which required the destruction of all chemical weapon agents, dispersal systems, and production facilities by... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Although herbicidal warfare use chemical substances, its main purpose is to disrupt agricultural food production and/or to destroy plants which provide cover or concealment to the enemy. The use of herbicides as a chemical weapon by the U.S. military during the Vietnam War has left tangible, long-term ... | https://en.wikipedia.org/wiki?curid=50073 |
Robert Boyle (; 25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, and inventor. Boyle is largely regarded today as the first modern chemist (a title some give to 8th century Islamic scholar Jabir ibn Hayyan), and therefore one of the founders of modern chemistry, and one of... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle Boyle received private tutoring in Latin, Greek, and French and when he was eight years old, following the death of his mother, he was sent to Eton College in England. His father's friend, Sir Henry Wotton, was then the provost of the college. During this time, his father hired a private tutor, Robert Care... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle They met frequently in London, often at Gresham College, and some of the members also had meetings at Oxford. Having made several visits to his Irish estates beginning in 1647, Robert moved to Ireland in 1652 but became frustrated at his inability to make progress in his chemical work. In one letter, he de... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle Among the critics of the views put forward in this book was a Jesuit, Francis Line (1595–1675), and it was while answering his objections that Boyle made his first mention of the law that the volume of a gas varies inversely to the pressure of the gas, which among English-speaking people is usually called ... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle It was during his time at Oxford that Boyle was a "Chevalier". The Chevaliers are thought to have been established by royal order a few years before Boyle's time at Oxford. The early part of Boyle's residence was marked by the actions of the victorious parliamentarian forces, consequently this period marke... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle In the leisure thus gained he wished to "recruit his spirits, range his papers", and prepare some important chemical investigations which he proposed to leave "as a kind of Hermetic legacy to the studious disciples of that art", but of which he did not make known the nature. His health became still worse i... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle He regarded the acquisition of knowledge as an end in itself, and in consequence he gained a wider outlook on the aims of scientific inquiry than had been enjoyed by his predecessors for many centuries. This, however, did not mean that he paid no attention to the practical application of science nor that h... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle He made considerable progress in the technique of detecting their ingredients, a process which he designated by the term "analysis". He further supposed that the elements were ultimately composed of particles of various sorts and sizes, into which, however, they were not to be resolved in any known way. He... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle Instead, Boyle argued that natural philosophers could use the design apparently on display in some parts of nature to demonstrate God's involvement with the world. He also attempted to tackle complex theological questions using methods derived from his scientific practices. In "Some Physico-Theological Con... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle He was a pioneer studying races, and he believed that all human beings, no matter how diverse their physical differences, came from the same source: Adam and Eve. He studied reported stories of parents' giving birth to different coloured albinos, so he concluded that Adam and Eve were originally white and ... | https://en.wikipedia.org/wiki?curid=50237 |
Robert Boyle As a founder of the Royal Society, he was elected a Fellow of the Royal Society (FRS) in 1663. Boyle's law is named in his honour. The Royal Society of Chemistry issues a Prize for Analytical Science, named in his honour. The Boyle Medal for Scientific Excellence in Ireland, inaugurated in 1899, is awarded... | https://en.wikipedia.org/wiki?curid=50237 |
Quantum Hall effect The quantum Hall effect (or integer quantum Hall effect) is a quantum-mechanical version of the Hall effect, observed in two-dimensional electron systems subjected to low temperatures and strong magnetic fields, in which the Hall conductance undergoes quantum Hall transitions to take on the quantize... | https://en.wikipedia.org/wiki?curid=50425 |
Quantum Hall effect This quantum Hall effect is referred to as the quantum anomalous Hall (QAH) effect. There is also a new concept of the quantum spin Hall effect which is an analogue of the quantum Hall effect, where spin currents flow instead of charge currents. The quantization of the Hall conductance has the impor... | https://en.wikipedia.org/wiki?curid=50425 |
Quantum Hall effect The MOSFET (metal-oxide-semiconductor field-effect transistor), invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959, enabled physicists to study electron behavior in a nearly ideal two-dimensional gas. In a MOSFET, conduction electrons travel in a thin surface layer, and a "gate" voltage... | https://en.wikipedia.org/wiki?curid=50425 |
Quantum Hall effect Most integer quantum Hall experiments are now performed on gallium arsenide heterostructures, although many other semiconductor materials can be used. In 2007, the integer quantum Hall effect was reported in graphene at temperatures as high as room temperature, and in the magnesium zinc oxide ZnO–Mg... | https://en.wikipedia.org/wiki?curid=50425 |
Quantum Hall effect The Quantum Hall effect, in addition to being observed in two-dimensional electron systems, can be observed in photons. Photons do not possess inherent electric charge, but through the manipulation of discrete optical resonators and quantum mechanical phase, therein creates an artificial magnetic fi... | https://en.wikipedia.org/wiki?curid=50425 |
Quantum Hall effect In the presence of disorder, which is the source of the plateaus seen in the experiments, this diagram is very different and the fractal structure is mostly washed away. Concerning physical mechanisms, impurities and/or particular states (e.g., edge currents) are important for both the 'integer' and... | https://en.wikipedia.org/wiki?curid=50425 |
Quantum Hall effect Defining the single atom Hall current as a rate a single electron charge formula_4 is making Kepler revolutions with angular frequency formula_5 and the induced Hall voltage as a difference between the hydrogen nucleus Coulomb potential at the electron orbital point and at infinity: One obtains the ... | https://en.wikipedia.org/wiki?curid=50425 |
Environmental engineering is a professional engineering discipline that takes from broad scientific topics like chemistry, biology, ecology, geology, hydraulics, hydrology, microbiology, and mathematics to create solutions that will protect and also improve the health of living organisms and improve the quality of the ... | https://en.wikipedia.org/wiki?curid=50702 |
Environmental engineering is a name for work that has been done since early civilizations, as people learned to modify and control the environmental conditions to meet needs. As people recognized that their health was related to the quality of their environment, they built systems to improve it. The ancient Indus Valle... | https://en.wikipedia.org/wiki?curid=50702 |
Environmental engineering Modern environmental engineering began in London in the mid-19th century when Joseph Bazalgette designed the first major sewerage system following the Great Stink. The city's sewer system conveyed raw sewage to the River Thames, which also supplied the majority of the city's drinking water, le... | https://en.wikipedia.org/wiki?curid=50702 |
Environmental engineering " Many universities offer environmental engineering programs through either the department of civil engineering or chemical engineering and also including electronic projects to develop and balance the environmental conditions. Environmental engineers in a civil engineering program often focus... | https://en.wikipedia.org/wiki?curid=50702 |
Environmental engineering Water distribution systems are designed and built to provide adequate water pressure and flow rates to meet various end-user needs such as domestic use, fire suppression, and irrigation. There are numerous wastewater treatment technologies. A wastewater treatment train can consist of a primary... | https://en.wikipedia.org/wiki?curid=50702 |
Environmental engineering Environmental engineers apply scientific and engineering principles to evaluate if there are likely to be any adverse impacts to water quality, air quality, habitat quality, flora and fauna, agricultural capacity, traffic, ecology, and noise. If impacts are expected, they then develop mitigati... | https://en.wikipedia.org/wiki?curid=50702 |
Jaroslav Heyrovský () (December 20, 1890 – March 27, 1967) was a Czech chemist and inventor. Heyrovský was the inventor of the polarographic method, father of the electroanalytical method, and recipient of the Nobel Prize in 1959 for his discovery and development of the polarographic methods of analysis. His main field... | https://en.wikipedia.org/wiki?curid=143705 |
Jaroslav Heyrovský Heyrovský's invention of the polarographic method dates from 1922 and he concentrated his whole further scientific activity on the development of this new branch of electrochemistry. He formed a school of Czech polarographers in the University, and was himself in the forefront of polarographic resear... | https://en.wikipedia.org/wiki?curid=143705 |
Jaroslav Heyrovský He was granted honorary membership in the American Academy of Arts and Sciences in 1933; in the Hungarian Academy of Sciences in 1955; the Indian Academy of Sciences, Bangalore, in 1955; the Polish Academy of Sciences, Warsaw, in 1962; was elected Corresponding Member of the German Academy of Science... | https://en.wikipedia.org/wiki?curid=143705 |
Fluorescent lamp A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp One of the first to explain it was the Irish scientist Sir George Stokes from the University of Cambridge in 1852, who named the phenomenon "fluorescence" after fluorite, a mineral many of whose samples glow strongly because of impurities. The explanation relied on the nature of electricity and light p... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp He went on to apply thin coatings of luminescent materials to the surfaces of these tubes. Fluorescence occurred, but the tubes were very inefficient and had a short operating life. Inquiries that began with the Geissler tube continued as even better vacuums were produced. The most famous was the evacu... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Nikola Tesla made similar experiments in the 1890s, devising high-frequency powered fluorescent bulbs that gave a bright greenish light, but as with Edison's devices, no commercial success was achieved. One of Edison's former employees created a gas-discharge lamp that achieved a measure of commercial ... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp These patents and the inventive efforts that supported them were to be of considerable value when the firm took up fluorescent lighting more than two decades later. At about the same time that Moore was developing his lighting system, Peter Cooper Hewitt invented the mercury-vapor lamp, patented in 190... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Although its light output relative to electrical consumption was better than that of other sources of light, the light it produced was similar to that of the Cooper-Hewitt lamp in that it lacked the red portion of the spectrum, making it unsuitable for ordinary lighting. The next step in gas-based ligh... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp The development of the neon light also was significant for the last key element of the fluorescent lamp, its fluorescent coating. In 1926 Jacques Risler received a French patent for the application of fluorescent coatings to neon light tubes. The main use of these lamps, which can be considered the fir... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp In 1934, Arthur Compton, a renowned physicist and GE consultant, reported to the GE lamp department on successful experiments with fluorescent lighting at General Electric Co., Ltd. in Great Britain (unrelated to General Electric in the United States). Stimulated by this report, and with all of the key... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp General Electric used its control of the patents to prevent competition with its incandescent lights and probably delayed the introduction of fluorescent lighting by 20 years. Eventually, war production required 24-hour factories with economical lighting and fluorescent lights became available. While t... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp They therefore dropped the Buttolph claim and paid $180,000 to acquire the Meyer, et al. application, which at that point was owned by a firm known as Electrons, Inc. The patent was duly awarded in December 1939. This patent, along with the Hull patent, put GE on what seemed to be firm legal ground, al... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp In the first years zinc orthosilicate with varying content of beryllium was used as greenish phosphor. Small additions of magnesium tungstate improved the blue part of the spectrum yielding acceptable white. After it was discovered that beryllium was toxic, halophosphate based phosphors took over. The ... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Electrons collide with and ionize noble gas atoms inside the bulb surrounding the filament to form a plasma by the process of impact ionization. As a result of avalanche ionization, the conductivity of the ionized gas rapidly rises, allowing higher currents to flow through the lamp. The fill gas helps ... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Some lamps have the tube bent into a circle, used for table lamps or other places where a more compact light source is desired. Larger U-shaped lamps are used to provide the same amount of light in a more compact area, and are used for special architectural purposes. Compact fluorescent lamps have seve... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Fluorescent lamps are negative differential resistance devices, so as more current flows through them, the electrical resistance of the fluorescent lamp drops, allowing for even more current to flow. Connected directly to a constant-voltage power supply, a fluorescent lamp would rapidly self-destruct b... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Fluorescent lamps can run directly from a direct current (DC) supply of sufficient voltage to strike an arc. The ballast must be resistive, and would consume about as much power as the lamp. When operated from DC, the starting switch is often arranged to reverse the polarity of the supply to the lamp e... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp The ballast dissipates some heat; electronic ballasts may be around 90% efficient. A fixed voltage drop occurs at the electrodes, which also produces heat. Some of the energy in the mercury vapor column is also dissipated, but about 85% is turned into visible and ultraviolet light. Not all the UV radia... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Cold cathode lamps are generally less efficient than thermionic emission lamps because the cathode fall voltage is much higher. Power dissipated due to cathode fall voltage does not contribute to light output. However, this is less significant with longer tubes. The increased power dissipation at tube ... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp These systems are standard equipment in 200–240 V countries (and for 100–120 V lamps up to about 30 watts). Before the 1960s, four-pin thermal starters and manual switches were used. A glow switch starter automatically preheats the lamp cathodes. It consists of a normally open bi-metallic switch in a s... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp In North America, low-cost lighting fixtures with an integrated electronic ballast use instant start on lamps originally designed for preheating, although it shortens lamp life. This ballast technology isn't common outside North America. "Rapid start" ballast designs provide windings within the ballast... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Nonetheless, Quick-start ballasts are also used in domestic (residential) installations because of the desirable feature that a Quick-start ballast light turns on nearly immediately after power is applied (when a switch is turned on). Quick-start ballasts are used only on 240 V circuits and are designe... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Additionally, the circuit power factor is almost 1.0, and no additional power factor correction is needed in the lighting installation. As the design requires that twice the supply voltage must be lower than the cold-cathode striking voltage (or the tubes would erroneously instant-start), this design c... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp 3 seconds), or for most reliable starting even at low temperatures and with low supply voltages, with a startup time of 2–4 seconds. The faster-start units may produce audible noise during start-up. Electronic starters only attempt to start a lamp for a short time when power is initially applied, and d... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp After a short time the voltage across the lamp reaches about 1 kV and the lamp instant-starts in cold cathode mode. The cathode filaments are still used for protection of the ballast from overheating if the lamp does not ignite. A few manufacturers use positive temperature coefficient (PTC) thermistors... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp These ballasts convert the incoming power to an output frequency in excess of . This increases lamp efficiency. These ballasts operate with voltages that can be almost 600 volts, requiring some consideration in housing design, and can cause a minor limitation in the length of the wire leads from the ba... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp The localized depletion of mercury vapor pressure manifests as pink luminescence of the base gas in the vicinity of one of the electrodes, and the operating lifetime of the lamp may be dramatically shortened. This can be an issue with some poorly designed inverters. The phosphors lining the lamp degrad... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Correlated color temperature (CCT) is a measure of the "shade" of whiteness of a light source compared with a blackbody. Typical incandescent lighting is 2700 K, which is yellowish-white. Halogen lighting is 3000 K. Fluorescent lamps are manufactured to a chosen CCT by altering the mixture of phosphors... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Colored objects appear muted. For example, a low CRI 6800 K halophosphate tube (an extreme example) will make reds appear dull red or even brown. Since the eye is relatively less efficient at detecting red light, an improvement in color rendering index, with increased energy in the red part of the spec... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Many compact fluorescent lamps integrate the auxiliary electronics into the base of the lamp, allowing them to fit into a regular light bulb socket. In US residences, fluorescent lamps are mostly found in kitchens, basements, or garages, but schools and businesses find the cost savings of fluorescent l... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp A typical 100 watt tungsten filament incandescent lamp may convert only 5% of its power input to visible white light (400–700 nm wavelength), whereas typical fluorescent lamps convert about 22% of the power input to visible white light. The efficacy of fluorescent tubes ranges from about 16 lumens per ... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp In suitably designed lamps, light can be more evenly distributed without point source of glare such as seen from an undiffused incandescent filament; the lamp is large compared to the typical distance between lamp and illuminated surfaces. Fluorescent lamps give off about one-fifth the heat of equivale... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp For large users of fluorescent lamps, recycling services are available in some areas, and may be required by regulation. In some areas, recycling is also available to consumers. Fluorescent lamps emit a small amount of ultraviolet (UV) light. A 1993 study in the US found that ultraviolet exposure from ... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Fluorescent lamps are a non-linear load and generate harmonic currents in the electrical power supply. The arc within the lamp may generate radio frequency noise, which can be conducted through power wiring. Suppression of radio interference is possible. Very good suppression is possible, but adds to t... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Fluorescent lamps with magnetic ballasts flicker at a normally unnoticeable frequency of 100 or 120 Hz and this flickering can cause problems for some individuals with light sensitivity; they are listed as problematic for some individuals with autism, epilepsy, lupus, chronic fatigue syndrome, Lyme dis... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp New fluorescent lamps may show a twisting spiral pattern of light in a part of the lamp. This effect is due to loose cathode material and usually disappears after a few hours of operation. Electromagnetic ballasts may also cause problems for video recording as there can be a so-called "beat effect" bet... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Overdriving a fluorescent lamp is a method of getting more light from each tube than is obtained under rated conditions. ODNO (Overdriven Normal Output) fluorescent tubes are generally used when there isn't enough room to put in more bulbs to increase the light. The method is effective, but generates s... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp This allows UV-induced fluorescence to be seen more easily (thereby allowing blacklight posters to seem much more dramatic). The blacklight lamps used in bug zappers do not require this refinement so it is usually omitted in the interest of cost; they are called simply "blacklite" (and not blacklite bl... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp The broadband is better for increasing Vitamin D3 in the body. Grow lamps contain phosphor blends that encourage photosynthesis, growth, or flowering in plants, algae, photosynthetic bacteria, and other light-dependent organisms. These often emit light primarily in the red and blue color range, which i... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Germicidal lamps have designations beginning with G, for example G30T8 for a 30-watt, diameter, long germicidal lamp (as opposed to an F30T8, which would be the fluorescent lamp of the same size and rating). Electrodeless induction lamps are fluorescent lamps without internal electrodes. They have been... | https://en.wikipedia.org/wiki?curid=144056 |
Fluorescent lamp Capacitive coupling with high-voltage power lines can light a lamp continuously at low intensity, depending on the intensity of the electric field, as shown in the image on the right. | https://en.wikipedia.org/wiki?curid=144056 |
Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic. It is a III-V direct band gap semiconductor with a zinc blende crystal structure. is used in the manufacture of devices such as microwave frequency integrated circuits, monolithic microwave integrated circuits, infrared light-emitting diodes, la... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide These crystals are called "semi-insulating", reflecting their high resistivity of 10–10 Ω·cm (which is quite high for a semiconductor, but still much lower than a true insulator like glass). Wet etching of GaAs industrially uses an oxidizing agent such as hydrogen peroxide or bromine water, and the sam... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide It is also used in the manufacture of Gunn diodes for the generation of microwaves. Another advantage of GaAs is that it has a direct band gap, which means that it can be used to absorb and emit light efficiently. Silicon has an indirect band gap and so is relatively poor at emitting light. As a wide d... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide Cray eventually built one GaAs-based machine in the early 1990s, the Cray-3, but the effort was not adequately capitalized, and the company filed for bankruptcy in 1995. Complex layered structures of gallium arsenide in combination with aluminium arsenide (AlAs) or the alloy AlGaAs can be grown using m... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide Such good mechanical characteristics also make it a suitable material for the rapidly developing field of nanoelectronics. Naturally, a GaAs surface cannot withstand the high temperatures needed for diffusion; however a viable and actively pursued alternative as of the 1980s was ion implantation. The s... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide For manufacturing solar cells, silicon has relatively low absorptivity for sunlight, meaning about 100 micrometers of Si is needed to absorb most sunlight. Such a layer is relatively robust and easy to handle. In contrast, the absorptivity of GaAs is so high that only a few micrometers of thickness are... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide In the early 1980s, the efficiency of the best GaAs solar cells surpassed that of conventional, crystalline silicon-based solar cells. In the 1990s, GaAs solar cells took over from silicon as the cell type most commonly used for photovoltaic arrays for satellite applications. Later, dual- and triple-ju... | https://en.wikipedia.org/wiki?curid=144143 |
Gallium arsenide Since the spectral position of the band gap is temperature dependent, it shifts about 0.4 nm/K. The measurement device contains a light source and a device for the spectral detection of the band gap. With the changing of the band gap, (0.4 nm/K) an algorithm calculates the temperature (all 250 ms). GaA... | https://en.wikipedia.org/wiki?curid=144143 |
Degenerate matter is a highly dense state of fermionic matter in which particles must occupy high states of kinetic energy to satisfy the Pauli exclusion principle. The description applies to matter composed of electrons, protons, neutrons or other fermions. The term is mainly used in astrophysics to refer to dense ste... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter Degeneracy pressure keeps dense stars in equilibrium, independent of the thermal structure of the star. A degenerate mass whose fermions have velocities close to the speed of light (particle energy larger than its rest mass energy) is called relativistic degenerate matter. The concept of degenerate st... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter Therefore, even though the plasma is cold, such particles must on average be moving very fast. Large kinetic energies lead to the conclusion that, in order to compress an object into a very small space, tremendous force is required to control its particles' momentum. Unlike a classical ideal gas, whos... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter While degeneracy pressure usually dominates at extremely high densities, it is the ratio of the two which determines degeneracy. Given a sufficiently drastic increase in temperature (such as during a red giant star's helium flash), matter can become non-degenerate without reducing its density. Degener... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter Most stars are supported against their own gravitation by normal thermal gas pressure, while in white dwarf stars the supporting force comes from the degeneracy pressure of the electron gas in their interior. In neutron stars, the degenerate particles are neutrons. A fermion gas in which all quantum s... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter In the core of a star, once hydrogen burning in nuclear fusion reactions stops, it becomes a collection of positively charged ions, largely helium and carbon nuclei, floating in a sea of electrons, which have been stripped from the nuclei. Degenerate gas is an almost perfect conductor of heat and does... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter Therefore, the phenomenon is the opposite of that normally found in matter where if the mass of the matter is increased, the object becomes bigger. In degenerate gas, when the mass is increased, the pressure is increased, and the particles become spaced closer together, so the object becomes smaller. ... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter During this shrinking, an electron-degenerate gas forms in the core, providing sufficient degeneracy pressure as it is compressed to resist further collapse. Above this mass limit, a neutron star (partially supported by neutron degeneracy pressure) or a black hole may be formed instead. Neutron degene... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter Typical separations are comparable with the size of the neutron and the range of the strong nuclear force, and it is actually the repulsive nature of the latter at small separations that primarily supports neutron stars more massive than 0.7 solar masses (which includes all measured neutron stars). In... | https://en.wikipedia.org/wiki?curid=144428 |
Degenerate matter Sufficiently dense matter containing protons experiences proton degeneracy pressure, in a manner similar to the electron degeneracy pressure in electron-degenerate matter: protons confined to a sufficiently small volume have a large uncertainty in their momentum due to the Heisenberg uncertainty princ... | https://en.wikipedia.org/wiki?curid=144428 |
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