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Halogen Free
Low smoke zero halogen or low smoke free of halogen (LSZH or LSOH or LS0H or LSFH or OHLS or ZHFR) is a material classification typically used for cable jacketing in the wire and cable industry. LSZH cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat. Description The first commercial thermoplastic LSZH material for cable jacketing was invented by Richard Skipper in 1979 and patented by Raychem Corporation. This invention resolved the challenge of incorporating sufficient inorganic filler, aluminium trihydrate (ALTH), into an appropriate thermoplastic matrix to suppress the fire and allow a char to be formed, which reduced emission of poisonous carbon gases and also smoke and carbon particles, whilst maintaining electrical insulation properties and physical properties required by the end application. The preferred inorganic filler to achieve flame retardation continues to be aluminium tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Cable
An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current. One or more electrical cables and their corresponding connectors may be formed into a ''cable assembly'', which is not necessarily suitable for connecting two devices but can be a partial product (e.g. to be soldered onto a printed circuit board with a connector mounted to the housing). Cable assemblies can also take the form of a cable tree or cable harness, used to connect many terminals together. Etymology The original meaning of ''cable'' in the electrical wiring sense was for submarine telegraph cables that were armoured with iron or steel wires. Early attempts to lay submarine cables without armouring failed because they were too easily damaged. The armouring in these early days (mid-19th century) was implemented in separate factories to the factories making the cable cores. These companies were specialists in manufacturing wire rope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventilation (architecture)
Ventilation is the intentional introduction of outdoor air into a space. Ventilation is mainly used to control indoor air quality by diluting and displacing indoor pollutants; it can also be used to control indoor temperature, humidity, and air motion to benefit thermal comfort, satisfaction with other aspects of indoor environment, or other objectives. The intentional introduction of outdoor air is usually categorized as either mechanical ventilation, natural ventilation, or mixed-mode ventilation (hybrid ventilation). * Mechanical ventilation is the intentional fan driven flow of outdoor air into a building. Mechanical ventilation systems may include supply fans (which push outdoor air into a building), exhaust fans (which draw air out of building and thereby cause equal ventilation flow into a building), or a combination of both. Mechanical ventilation is often provided by equipment that is also used to heat and cool a space. * Natural ventilation is the intentional passive fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASTM
ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. Some 12,575 ASTM voluntary consensus standards operate globally. The organization's headquarters is in West Conshohocken, Pennsylvania, about northwest of Philadelphia. It is founded in 1902 as the American Section of the International Association for Testing Materials (see also International Organization for Standardization). History A group of scientists and engineers, led by Charles Dudley, formed ASTM in 1898 to address the frequent rail breaks affecting the fast-growing railroad industry. The group developed a standard for the steel used to fabricate rails. Originally called the "American Society for Testing Materials" in 1902, it became the "American Society for Testing And Materials" in 1961. In 2001, ASTM official ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
King's Cross Fire
The King's Cross fire was a 1987 fire in a London Underground station with 31 fatalities, after a fire under a wooden escalator suddenly spread into the underground ticket hall in a flashover. The fire began at approximately 19:30 on 18 November 1987 at King's Cross St Pancras tube station, a major interchange on the London Underground. As well as the mainline railway stations above ground and subsurface platforms for the Metropolitan, Circle and Hammersmith & City lines, there were platforms deeper underground for the Northern, Piccadilly, and Victoria lines. The fire started under a wooden escalator serving the Piccadilly line and, at 19:45, erupted in a flashover into the underground ticket hall, killing 31 people and injuring 100. A public inquiry was conducted from February to June 1988. Investigators reproduced the fire twice, once to determine whether grease under the escalator was ignitable, and the other to determine whether a computer simulation of the fire—which w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Falklands War
The Falklands War ( es, link=no, Guerra de las Malvinas) was a ten-week undeclared war between Argentina and the United Kingdom in 1982 over two British dependent territories in the South Atlantic: the Falkland Islands and its territorial dependency, South Georgia and the South Sandwich Islands. The conflict began on 2 April, when Argentina invaded and occupied the Falkland Islands, followed by the invasion of South Georgia the next day. On 5 April, the British government dispatched a naval task force to engage the Argentine Navy and Air Force before making an amphibious assault on the islands. The conflict lasted 74 days and ended with an Argentine surrender on 14 June, returning the islands to British control. In total, 649 Argentine military personnel, 255 British military personnel, and three Falkland Islanders were killed during the hostilities. The conflict was a major episode in the protracted dispute over the territories' sovereignt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exocet
The Exocet () is a French-built anti-ship missile whose various versions can be launched from surface vessels, submarines, helicopters and fixed-wing aircraft. Etymology The missile's name was given by M. Guillot, then the technical director at Nord Aviation. It is the French word for flying fish, from the Latin ''exocoetus'', a transliteration of the Greek name for the fish that sometimes flew into a boat: (''exōkoitos''), literally "lying down outside (, ), sleeping outside". Description The Exocet is built by MBDA, a European missile company. Development began in 1967 by Nord as a ship-launched weapon named the MM38. A few years later, Aerospatiale and Nord merged. The basic body design was based on the Nord AS-30 air-to-ground tactical missile. The sea-launched MM38 entered service in 1975, whilst the air-launched AM39 Exocet began development in 1974 and entered service with the French Navy five years later in 1979. The relatively compact missile is designed for at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HMS Sheffield (D80)
HMS ''Sheffield'' was a Type 42 guided missile destroyer and the second Royal Navy ship to be named after the city of Sheffield in Yorkshire. Commissioned on 16 February 1975 the ''Sheffield'' was part of the Task Force 317 sent to the Falkland Islands during the Falklands War. She was struck and heavily damaged by an Exocet air-launched anti-ship missile from an Argentine Super Étendard aircraft on 4 May 1982 and foundered while under tow on 10 May 1982. Design The first of the Type 42 class, ''Sheffield'', was initially fitted with the odd-looking "Mickey Mouse" ears on her funnel tops which were in fact exhaust deflectors - "Loxton bends" - for the Rolls-Royce Olympus TM3B gas turbines, to guide the high-temperature exhaust efflux sidewards and minimise damage to overhead aerials. As this provided a prominent target for then-new infrared homing missiles, only ''Sheffield'' and the next two in the class, the Argentinian ''Hércules'' and ''Santísima Trinidad'', had the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit. The opposite of a short circuit is an "open circuit", which is an infinite resistance between two nodes. Definition A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors. In circuit analysis, a ''short circuit'' is defined as a connection between two nodes that forces them to be at the same voltage. In an 'ideal' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power Plant
A nuclear power plant (NPP) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a electric generator, generator that produces electricity. , the International Atomic Energy Agency reported there were 422 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction. Nuclear plants are very often used for base load since their operations, maintenance, and fuel costs are at the lower end of the spectrum of costs. However, building a nuclear power plant often spans five to ten years, which can accrue to significant financial costs, depending on how the initial investments are financed. Nuclear power plants have a carbon footprint comparable to that of renewable energy such as photovoltaic power station, solar farms and wind farms, and much lower than fossil fuels such as gas-fired ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, or people. Special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanks
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engine; usually their main armament is mounted in a turret. They are a mainstay of modern 20th and 21st century ground forces and a key part of combined arms combat. Modern tanks are versatile mobile land weapons platforms whose main armament is a large-caliber tank gun mounted in a rotating gun turret, supplemented by machine guns or other ranged weapons such as anti-tank guided missiles or rocket launchers. They have heavy vehicle armour which provides protection for the crew, the vehicle's munition storage, fuel tank and propulsion systems. The use of tracks rather than wheels provides improved operational mobility which allows the tank to overcome rugged terrain and adverse conditions such as mud and ice/snow better than wheeled vehicles, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rail Carriage
A railroad car, railcar ( American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and UIC), also called a train car, train wagon, train carriage or train truck, is a vehicle used for the carrying of cargo or passengers on a rail transport system (a railroad/railway). Such cars, when coupled together and hauled by one or more locomotives, form a train. Alternatively, some passenger cars are self-propelled in which case they may be either single railcars or make up multiple units. The term "car" is commonly used by itself in American English when a rail context is implicit. Indian English sometimes uses "bogie" in the same manner, though the term has other meanings in other variants of English. In American English, "railcar" is a generic term for a railway vehicle; in other countries "railcar" refers specifically to a self-propelled, powered, railway vehicle. Although some cars exist for the ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
