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Sorbothane
Sorbothane is the brand name of a synthetic viscoelastic urethane polymer used as a shock absorber and vibration damper. It is manufactured by Sorbothane, Inc., based in Kent, Ohio. History Sorbothane was invented and patented in 1982 by Dr. Maurice Hiles, a British inventor. It was prepared by mixing polyol and isocyanate. His research into the energy dissipation properties of human soft tissue disclosed a structure very similar to an interpenetrating polymer network. This led to his synthesis of the first commercial simultaneous interpenetrating network, now called Sorbothane. Dr. Hiles wrote in his patent "The resulting solid polymer behaves like a quasi-liquid, being readily deformed by an applied force and slow to recover, although in the absence of such a force it takes up a defined shape and volume". In 1976, he contacted the National Research Development Corporation (NRDC) about his invention; the NRDC spent almost £10,000 in helping him to improve and patent the poly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quiet PC
A quiet, silent or fanless PC is a personal computer that makes very little or no noise. Common uses for quiet PCs include video editing, sound mixing and home theater PCs, but noise reduction techniques can also be used to greatly reduce the noise from servers. There is currently no standard definition for a "quiet PC", and the term is generally not used in a business context, but by individuals and the businesses catering to them. A proposed general definition is that the sound emitted by such PCs should not exceed 30 dBA, but in addition to the average sound pressure level, the frequency spectrum and dynamics of the sound are important in determining if the sound of the computer is noticed. Sounds with a smooth frequency spectrum (lacking audible tonal peaks), and little temporal variation are less likely to be noticed. The character and amount of other noise in the environment also affects how much sound will be noticed or masked, so a computer may be quiet with relation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Foam
Memory foam consists mainly of polyurethane with additional chemicals that increase its viscosity and density. It is often referred to as " viscoelastic" polyurethane foam, or low-resilience polyurethane foam ( LRPu). The foam bubbles or ‘cells’ are open, effectively creating a matrix through which air can move. Higher-density memory foam softens in reaction to body heat, allowing it to mold to a warm body in a few minutes. Newer foams may recover their original shape more quickly. Mechanics Memory foam derives its viscoelastic properties from several effects, due to the material's internal structure. The network effect is the force working to restore the foam's structure when it is deformed. This effect is generated by the deformed porous material pushing outwards to restore its structure against an applied pressure. Three effects work against the network effect, slowing the regeneration of the foam's original structure: * The pneumatic effect, caused by the time it takes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibration Isolation
Vibration isolation is the process of isolating an object, such as a piece of equipment, from the source of vibrations. Vibration is undesirable in many domains, primarily engineered systems and habitable spaces, and methods have been developed to prevent the transfer of vibration to such systems. Vibrations propagate via mechanical waves and certain mechanical linkages conduct vibrations more efficiently than others. Passive vibration isolation makes use of materials and mechanical linkages that absorb and damp these mechanical waves. Active vibration isolation involves sensors and actuators that produce disruptive interference that cancels-out incoming vibration. Passive isolation "Passive vibration isolation" refers to vibration isolation or mitigation of vibrations by passive techniques such as rubber pads or mechanical springs, as opposed to "active vibration isolation" or "electronic force cancellation" employing electric power, sensors, actuators, and control systems. Passive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Foam
Acoustic foam is an open celled foam used for acoustic treatment. It attenuates airbone sound waves, reducing their amplitude, for the purposes of noise reduction or noise control. The energy is dissipated as heat. Acoustic foam can be made in several different colors, sizes and thickness. Acoustic foam can be attached to walls, ceilings, doors, and other features of a room to control noise levels, vibration, and echoes. Many acoustic foam products are treated with dyes and/or fire retardants. Uses The objective of acoustic foam is to improve or change a room’s sound qualities by controlling residual sound through absorption. This purpose requires strategic placement of acoustic foam panels on walls, ceilings, floors and other surfaces. Proper placement can help effectively manage resonance within the room and help give the room the desired sonic qualities. Acoustic enhancement The objective of acoustic foam is to enhance the sonic properties of a room by effectively ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscoelasticity
In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly with time when a stress is applied. Elastic materials strain when stretched and immediately return to their original state once the stress is removed. Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain. Whereas elasticity is usually the result of bond stretching along crystallographic planes in an ordered solid, viscosity is the result of the diffusion of atoms or molecules inside an amorphous material.Meyers and Chawla (1999): "Mechanical Behavior of Materials", 98-103. Background In the nineteenth century, physicists such as Maxwell, Boltzmann, and Kelvin researched and experimented with creep and recovery of glasses, metals, and rubbers. Viscoelasticity was further examined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program, aeronautics research, and outer space, space research. NASA was National Aeronautics and Space Act, established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo program, Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion (spacecraft), Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew Program, Commercial Crew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anechoic Chamber
An anechoic chamber (''an-echoic'' meaning "non-reflective") is a room designed to stop reflections of either sound or electromagnetic waves. They are also often isolated from energy entering from their surroundings. This combination means that a person or detector exclusively hears direct sounds (no reflected sounds), in effect simulating being outside in a free field. Anechoic chambers, a term coined by American acoustics expert Leo Beranek, were initially exclusively used to refer to acoustic anechoic chambers. Recently, the term has been extended to other RF and Sonar anechoic chambers, which eliminate reflection and external noise caused by electromagnetic waves. Anechoic chambers range from small compartments the size of household microwave ovens to ones as large as aircraft hangars. The size of the chamber depends on the size of the objects and frequency ranges being tested. Acoustic anechoic chambers The requirement for what was subsequently called an anechoic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bushing (isolator)
A bushing or rubber bushing is a type of vibration isolator. It provides an interface between two parts, damping the energy transmitted through the bushing. A common application is in vehicle suspension systems, where a bushing made of rubber (or, more often, synthetic rubber or polyurethane) separates the faces of two metal objects while allowing a certain amount of movement. This movement allows the suspension parts to move freely, for example, when traveling over a large bump, while minimizing transmission of noise and small vibrations through to the chassis of the vehicle. A rubber bushing may also be described as a flexible mounting or antivibration mounting. These bushings often take the form of an annular cylinder of flexible material inside a metallic casing or outer tube. They might also feature an internal ''crush tube'' which protects the bushing from being crushed by the fixings which hold it onto a threaded spigot. Many different types of bushing designs exist. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoprene
Neoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion Rubbers" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. Neoprene is sold either as solid rubber or in latex form and is used in a wide variety of commercial applications, such as laptop sleeves, orthopaedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet-applied elastomeric membranes or flashings, and automotive fan belts. Production Neoprene is produced by free-radical polymerization of chloroprene. In commercial production, this polymer is prepared by free radical emulsion polymerization. Polymerization is initiated using potassium persulfate. Bifunctional nucleophiles, metal oxides ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recoil Pad
A recoil pad is a piece of rubber, foam, leather, or other soft material usually attached to the buttstock of a rifle or shotgun. Recoil pads may also be worn around the shoulder with straps, placing the soft material between the buttstock and the shoulder of the person firing the gun. The purpose of this device is to provide additional padding between the typically hard buttstock surface and the user's shoulder, to reduce the amount of felt recoil of the firearm, and to prevent slippage on the shooter's clothing while aiming. Image:Recoil_Pad_Remington_870.jpg, Remington 870 The Remington Model 870 is a pump-action shotgun manufactured by Remington Arms Company, LLC. It is widely used by the public for shooting sports, hunting and self-defense, as well as by law enforcement and military organizations worldwide. ... shotgun equipped with a recoil pad. {{Firearms Firearm components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rugby Football
Rugby football is the collective name for the team sports of rugby union and rugby league. Canadian football and, to a lesser extent, American football were once considered forms of rugby football, but are seldom now referred to as such. The governing body of Canadian football, Football Canada, was known as the Canadian Rugby Union as late as 1967, more than fifty years after the sport parted ways with rugby rules. Rugby football started about 1845 at Rugby School in Rugby, Warwickshire, England, although forms of football in which the ball was carried and tossed date to the Middle Ages (see medieval football). Rugby football spread to other English public schools in the 19th century and across the British Empire as former pupils continued to play it. Rugby football split into two codes in 1895, when twenty-one clubs from the North of England left the Rugby Football Union to form the Northern Rugby Football Union (renamed the Rugby Football League in 1922) at the Georg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cricket
Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by striking the ball bowled at one of the wickets with the bat and then running between the wickets, while the bowling and fielding side tries to prevent this (by preventing the ball from leaving the field, and getting the ball to either wicket) and dismiss each batter (so they are "out"). Means of dismissal include being bowled, when the ball hits the stumps and dislodges the bails, and by the fielding side either catching the ball after it is hit by the bat, but before it hits the ground, or hitting a wicket with the ball before a batter can cross the crease in front of the wicket. When ten batters have been dismissed, the innings ends and the teams swap roles. The game is adjudicated by two umpires, aided by a third umpire and match ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
