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Manganin
Manganin is a trademarked name for an alloy of typically 84.2% copper, 12.1% manganese, and 3.7% nickel. It was first developed by Edward Weston in 1892, improving upon his Constantan (1887). Manganin foil and wire is used in the manufacture of resistors, particularly ammeter shunts, because of its virtually zero temperature coefficient of resistance value and long term stability. Several Manganin resistors served as the legal standard for the ohm in the United States from 1901 to 1990. Manganin wire is also used as an electrical conductor in cryogenic systems, minimizing heat transfer between points which need electrical connections. Manganin is also used in gauges for studies of high-pressure shock waves (such as those generated from the detonation of explosives) because it has low strain sensitivity but high hydrostatic pressure Hydrostatics is the branch of fluid mechanics that studies fluids at hydrostatic equilibrium and "the pressure in a fluid or exerted by a fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistor
A resistor is a passive two-terminal electronic component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of electrical power as heat may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity. Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resisto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shunt (electrical)
A shunt is a device that is designed to provide a low-resistance path for an electrical current in a Electrical network, circuit. It is typically used to divert current away from a system or Electronic component, component in order to prevent overcurrent. Electrical shunts are commonly used in a variety of applications including power distribution systems, electrical measurement systems, automotive and marine applications. Defective device bypass One example is in miniature Christmas lights (holiday decoration), Christmas lights which are series circuit, wired in series. When the Electrical filament, filament burns out in one of the incandescent light bulbs, the full line voltage appears across the burnt out bulb. A shunt resistor, which has been connected parallel circuits, in parallel across the filament before it burnt out, will then short out to bypass the burnt filament and allow the rest of the string to light. If too many lights burn out however, a shunt will also burn o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Named Alloys
This is a list of named alloys grouped alphabetically by the metal with the highest percentage. Within these headings, the alloys are also grouped alphabetically. Some of the main alloying elements are optionally listed after the alloy names. Alloys by base metal Aluminium * AA-8000: used for electrical building wire in the U.S. per the National Electrical Code, replacing AA-1350. * Al–Li (2.45% lithium): aerospace applications, including the Space Shuttle * Alnico (nickel, cobalt): used for permanent magnets * Aluminium–Scandium (scandium) * Birmabright (magnesium, manganese): used in car bodies, mainly used by Land Rover cars. * Devarda's alloy (45% Al, 50% Cu, 5% Zn): chemical reducing agent. * Duralumin (copper) * Hiduminium or R.R. alloys (2% copper, iron, nickel): used in aircraft pistons * Hydronalium (up to 12% magnesium, 1% manganese): used in shipbuilding, resists seawater corrosion * Italma (3.5% magnesium, 0.3% manganese): formerly used to make coinage of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese
Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent, as a rubber additive, and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide. Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes. Manganese is commonly found in labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Weston (chemist)
Edward Weston (May 9, 1850 – August 20, 1936) was an English-born American chemist and engineer noted for his achievements in electroplating and his development of the electrochemical cell, named the Weston cell, for the voltage standard.History of Weston Aerospace , Weston – the Man (1850-1936) Weston was a competitor of in the early days of electricity generation and distribution.Edward Weston (1850-1936) . Corrosion Doctors Biography Born in |
John Forrest Kelly
John Forrest Kelly (March 28, 1859, in the vicinity of Carrick-on-Suir, Ireland – 1922) was an American electrical engineer who made early advances in alternating current equipment. Early life Kelly was the son of two Fenian schoolteachers, Jeremiah and Kate Forrest Kelly, who had eleven other children; he emigrated to America in 1873. He was educated in Stevens Institute of Technology, Hoboken, New Jersey, received the degree of B. L. in 1878 and that of Ph.D. in 1881. His sister was the activist and surgeon Dr. Gertrude Kelly. Career His first occupation was as assistant to Thomas A. Edison, in the Menlo Park laboratory, his work then principally relating to the chemistry of rare earths. Late in 1879 Mr. Kelly became electrical engineer of the New York branch of the Western Electric Company. This was the time when the telephone was being generally introduced, and when dynamos were being first applied to telegraphic purposes. In 1882 he became laboratory assistant to Edwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferromanganese
Ferromanganese is an alloy of iron and manganese, with other elements such as silicon, carbon, sulfur, nitrogen and phosphorus. The primary use of ferromanganese is as a type of processed manganese source to add to different types of steel, such as stainless steel. Global production of low-carbon ferromanganese (i.e. alloys with less than 2% carbon content) reached 1.5 megatons in 2010. Physical and chemical properties The properties of ferromanganese vary considerably with the precise type and composition of the alloy. The melting point is generally between and . The density of the alloy depend slightly on the types of impurities present, but is generally around . Production Sources of manganese ore generally also contain iron oxides. As manganese has a more negative free energy of oxidation than iron, i.e. is chemically harder to reduce, during the reduction of manganese ore, iron is also reduced and mixed with the manganese in the melt. This is unlike other oxides such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluid Statics
In physics, a fluid is a liquid, gas, or other material that may continuously move and deform (''flow'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear force applied to them. Although the term ''fluid'' generally includes both the liquid and gas phases, its definition varies among branches of science. Definitions of '' solid'' vary as well, and depending on field, some substances can have both fluid and solid properties. Non-Newtonian fluids like Silly Putty appear to behave similar to a solid when a sudden force is applied. Substances with a very high viscosity such as pitch appear to behave like a solid (see pitch drop experiment) as well. In particle physics, the concept is extended to include fluidic matters other than liquids or gases. A fluid in medicine or biology refers to any liquid constituent of the body ( body fluid), whereas "liquid" is not used in this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strain (materials Science)
In mechanics, strain is defined as relative deformation, compared to a position configuration. Different equivalent choices may be made for the expression of a strain field depending on whether it is defined with respect to the initial or the final configuration of the body and on whether the metric tensor or its dual is considered. Strain has dimension of a length ratio, with SI base units of meter per meter (m/m). Hence strains are dimensionless and are usually expressed as a decimal fraction or a percentage. Parts-per notation is also used, e.g., parts per million or parts per billion (sometimes called "microstrains" and "nanostrains", respectively), corresponding to μm/m and nm/m. Strain can be formulated as the spatial derivative of displacement: \boldsymbol \doteq \cfrac\left(\mathbf - \mathbf\right) = \boldsymbol'- \boldsymbol, where is the identity tensor. The displacement of a body may be expressed in the form , where is the reference position of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive Material
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be: * chemical energy, such as nitroglycerin or grain dust * pressurized gas, such as a gas cylinder, aerosol can, or boiling liquid expanding vapor explosion * nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239 Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are sai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Waves
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium, but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Pressure
In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. ''High pressure'' usually means pressures of thousands (kilo bars) or millions (megabars) of times atmospheric pressure (about 1 bar or 100,000 Pa). History and overview Percy Williams Bridgman received a Nobel Prize in 1946 for advancing this area of physics by two magnitudes of pressure (400 MPa to 40 GPa). The list of founding fathers of this field includes also the names of Harry George Drickamer, Tracy Hall, Francis P. Bundy, , and . It was by applying high pressure as well as high temperature to carbon that synthetic diamonds were first produced alongside many other interesting discoveries. Almost any material when subjected to high pressure will compact itself into a denser form, for example, quartz (also called silica or silicon dioxide) will first adopt a denser form known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
