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Brake Lining
Brake linings are the consumable surfaces in brake systems, such as drum brakes and disc brakes used in transport vehicles. History Brake linings were invented by Bertha Benz (the wife of Karl Benz, who invented the first patented automobile) during her long-distance car trip, the first in the world, in August 1888, when she told a shoemaker to nail leather onto the brake blocks. The first asbestos brake linings were developed in 1908 by Herbert Frood. Although Frood was the first to implement the use of asbestos brake linings, the heat dissipation properties of the fibres were tested by various scientists, including materials chemist Gwilym Price, who did most of his research and testing at Cambridge, United Kingdom, and various Cambridge-funded institutions. Structure and function Brake linings are composed of a relatively soft but tough and heat-resistant material with a high coefficient of dynamic friction (and ideally an identical coefficient of static friction) typically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brake Shoes
A railway brake is a type of brake used on the cars of railway trains to enable deceleration, control acceleration (downhill) or to keep them immobile when parked. While the basic principle is similar to that on road vehicle usage, operational features are more complex because of the need to control multiple linked carriages and to be effective on vehicles left without a prime mover. Clasp brakes are one type of brakes historically used on trains. Early developments In the earliest days of railways, braking technology was primitive. The first trains had brakes operative on the locomotive tender and on vehicles in the train, where "porters" or, in the United States brakemen, travelling for the purpose on those vehicles operated the brakes. Some railways fitted a special deep-noted brake whistle to locomotives to indicate to the porters the necessity to apply the brakes. All the brakes at this stage of development were applied by operation of a screw and linkage to brake blo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disc Brake
A disc brake is a type of brake that uses the #Calipers, calipers to squeeze pairs of #Brake pads, pads against a disc (sometimes called a [brake] rotor) to create friction. There are two basic types of brake pad friction mechanisms: abrasive friction and adherent friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into heat, which must be dissipated to the environment. Hydraulic brakes, Hydraulically Actuator, actuated disc brakes are the most commonly used mechanical device for slowing motor vehicles. The principles of a disc brake apply to almost any rotating shaft. The components include the disc, master cylinder, and caliper, which contain at least one cylinder and two Brake pad, brake pads on both sides of the rotating disc. Design The development of disc-type brakes began in England in the 1890s. In 1902, the Lanchester Motor Company designed bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WVA Number
WVA numbers (German: ''Waren-Vertriebs-Artikel-Nummern'') are a reference and assignment system for brake linings, clutch facings, brake shoes and other friction materials which will especially be used in road vehicles but also in mechanical engineering. The WVA numbering system has been developed by the "VRI-Verband der Reibbelagindustrie" (Federation of Friction Industry), Cologne / Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu .... The VRI is the German Federation of Friction Industry and a member of FEMFM - Federation of European Manufacturers of Friction Materials. Taking the dimensionally determined parameters of the friction materials into account the system assigns the differently dimensioned linings to the respective areas of application and use and accordingly off ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spindle (tool)
In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer to the entire rotary unit, including not only the shaft itself, but its bearings and anything attached to it ( chuck, etc.). Spindles are electrically or pneumatically powered and come in various sizes. They are versatile in terms of material it can work with. Materials that spindles work with include embroidery, foam, glass, wood, etc. A machine tool may have several spindles, such as the headstock and tailstock spindles on a bench lathe. The main spindle is usually the biggest one. References to "the spindle" without further qualification imply the main spindle. Some machine tools that specialize in high-volume mass production have a group of 4, 6, or even more main spindles. These are called multispindle machines. For example, gang drills and many screw m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elevator
An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems such as a hoist, although some pump hydraulic fluid to raise a cylindrical piston like a jack. Elevators are used in agriculture and manufacturing to lift materials. There are various types, like chain and bucket elevators, grain augers, and hay elevators. Modern buildings often have elevators to ensure accessibility, especially where ramps aren't feasible. High-speed elevators are common in skyscrapers. Some elevators can even move horizontally. History Pre-industrial era The earliest known reference to an elevator is in the works of the Roman architect Vitruvius, who reported that Archimedes ( – ) built his first elevator probably in 236 BC. Sources from later periods mention elevators as cabs on a hemp rope, powered by people o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aramid
Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated bulletproof vest, body armor cloth, fabric and ballistic composites, in marine cordage, marine hull reinforcement, as an asbestos substitute, and in various lightweight consumer items ranging from phone cases to tennis rackets. The chain molecules in the fibers are highly oriented along the fiber axis. As a result, a higher proportion of the chemical bond contributes more to fiber strength than in many other synthetic fibres in the world. Aramids have a very high melting point (>). Common aramid brand names include Kevlar, Nomex, and Twaron. Terminology and chemical structure The term ''aramid'' is shortened from ''aromatic polyamide''. It was introduced in 1972, accepted in 1974 by the Federal Trade Commission of the USA as the name of a generic category of fiber distinct from nylon, and adopted by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peritoneal Mesothelioma
Peritoneal mesothelioma is the name given to the cancer that attacks the lining of the abdomen. This type of cancer affects the lining that protects the contents of the abdomen and provides a lubricating fluid to enable the organs to move and work properly. The peritoneum is made of two parts, the visceral and parietal peritoneum. The visceral peritoneum covers the internal organs and makes up most of the outer layer of the intestinal tract. Covering the abdominal cavity is the parietal peritoneum. Symptoms and signs Symptoms of peritoneal mesothelioma include weight loss and abdominal pain and swelling due to a buildup of fluid in the abdomen. Other symptoms of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and fever. If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face. Causes As for other mesotheliomas, asbestos is a known caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleural
The pleural cavity, or pleural space (or sometimes intrapleural space), is the potential space between the pulmonary pleurae, pleurae of the pleural sac that surrounds each lung. A small amount of serous fluid, serous pleural fluid is maintained in the pleural cavity to enable lubrication between the pleurae, membranes, and also to create a pressure gradient. The serous membrane that covers the surface of the lung is the visceral pleura and is separated from the outer membrane, the parietal pleura, by just the film of pleural fluid in the pleural cavity. The visceral pleura follows the fissures of the lung and the root of the lung structures. The parietal pleura is attached to the mediastinum, the upper surface of the thoracic diaphragm, diaphragm, and to the inside of the ribcage. Structure In humans, the left and right lungs are completely separated by the mediastinum, and there is no communication between their pleural cavities. Therefore, in cases of a unilateral pneumothor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institutes Of Health
The National Institutes of Health (NIH) is the primary agency of the United States government responsible for biomedical and public health research. It was founded in 1887 and is part of the United States Department of Health and Human Services (HHS). Many NIH facilities are located in Bethesda, Maryland, and other nearby suburbs of the Washington metropolitan area, with other primary facilities in the Research Triangle Park in North Carolina and smaller satellite facilities located around the United States. The NIH conducts its scientific research through the NIH Intramural Research Program (IRP) and provides significant biomedical research funding to non-NIH research facilities through its Extramural Research Program. , the IRP had 1,200 principal investigators and more than 4,000 postdoctoral fellows in basic, translational, and clinical research, being the largest biomedical research institution in the world, while, as of 2003, the extramural arm provided 28% of biomedical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrysotile
Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United StatesOccupational Safety and Health Administration, U.S. Department of Labor (2007)29 C.F.R. 1910.1001 Appendix J. and a similar proportion in other countries.Institut national de recherche sur la sécurité (1997).Amiante." ''Fiches toxicologiques.'' n° 167. (in French) It is a soft, fibrous silicate mineral in the serpentine subgroup of phyllosilicates; as such, it is distinct from other asbestiform minerals in the amphibole group. Its idealized chemical formula is Mg( Si O)( OH). The material has physical properties which make it desirable for inclusion in building materials, but poses serious health risks when dispersed into air and inhaled. Polytypes Three polytypes of chrysotile are known. These are very difficult to distinguish in hand specimens, and polarized light microscopy must normally be used. Some older publ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brake Fade
Brake fade (or vehicle braking system fade) is the reduction in stopping power that can occur after repeated or sustained application of the brakes of a vehicle, especially in high load or high speed conditions. Brake fade can be a factor in any vehicle that uses a friction braking system including automobiles, trucks, motorcycles, airplanes, and bicycles. Brake fade is caused by a buildup of heat in the braking surfaces and the subsequent changes and reactions in the brake system components and can be experienced with both drum brakes and disc brakes. Loss of stopping power, or fade, can be caused by friction fade, mechanical fade, or fluid fade. Brake fade can be significantly reduced by appropriate equipment and materials design and selection, as well as good cooling. Brake fade occurs most often during high performance driving or when going down a long, steep hill. It is more prevalent in drum brakes due to their configuration. Disc brakes are much more resistant to brake fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outgassing
Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which are phase transitions of a substance into a gas), as well as desorption, seepage from cracks or internal volumes, and gaseous products of slow chemical reactions. Boiling is generally thought of as a separate phenomenon from outgassing because it consists of a phase transition of a liquid into a vapor of the same substance. In a vacuum Outgassing is a challenge to creating and maintaining clean high- vacuum environments. NASA and ESA maintain lists of materials with low-outgassing properties suitable for use in spacecraft, as outgassing products can condense onto optical elements, thermal radiators, or solar cells and obscure them. Materials not normally considered absorbent can release enough lightweight molecules to interfere wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
