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RHA (armour)
Rolled homogeneous armour (RHA) is a type of vehicle armour made of a single steel composition hot-rolled to improve its material characteristics, as opposed to layered or cemented armour. Its first common application was in tanks. After World War II, it began to fall out of use on main battle tanks and other armoured fighting vehicles intended to see front-line combat as new anti-tank weapon technologies were developed which were capable of relatively easily penetrating rolled homogeneous armour plating even of significant thickness. Today, the term is primarily used as a unit of measurement of the protection offered by armour on a vehicle (often composed of materials that may not actually contain steel, or even contain any metals) in equivalent ''millimetres of RHA'', referring to the thickness of RHA that would provide the same protection. Typically, modern composite armour can provide the same amount of protection with much thinner and lighter construction than its protect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vehicle Armour
Military vehicles are commonly armoured (or armored; see spelling differences) to withstand the impact of shrapnel, bullets, shells, rockets, and missiles, protecting the personnel inside from enemy fire. Such vehicles include armoured fighting vehicles like tanks, aircraft, and ships. Civilian vehicles may also be armoured. These vehicles include cars used by officials (e.g., presidential limousines), reporters and others in conflict zones or where violent crime is common. Civilian armoured cars are also routinely used by security firms to carry money or valuables to reduce the risk of highway robbery or the hijacking of the cargo. Armour may also be used in vehicles to protect from threats other than a deliberate attack. Some spacecraft are equipped with specialised armour to protect them against impacts from micrometeoroids or fragments of space debris. Modern aircraft powered by jet engines usually have them fitted with a sort of armour in the form of an aramid composite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projectile
A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found in warfare and sports (for example, a thrown baseball, kicked football, fired bullet, shot arrow, stone released from catapult). In ballistics mathematical equations of motion are used to analyze projectile trajectories through launch, flight, and impact. Motive force Blowguns and pneumatic rifles use compressed gases, while most other guns and cannons utilize expanding gases liberated by sudden chemical reactions by propellants like smokeless powder. Light-gas guns use a combination of these mechanisms. Railguns utilize electromagnetic fields to provide a constant acceleration along the entire length of the device, greatly increasing the muzzle velocity. Some projectiles provide propulsion during flight by means of a rocket engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wayback Machine
The Wayback Machine is a digital archive of the World Wide Web founded by the Internet Archive, a nonprofit based in San Francisco, California. Created in 1996 and launched to the public in 2001, it allows the user to go "back in time" and see how websites looked in the past. Its founders, Brewster Kahle and Bruce Gilliat, developed the Wayback Machine to provide "universal access to all knowledge" by preserving archived copies of defunct web pages. Launched on May 10, 1996, the Wayback Machine had more than 38.2 million records at the end of 2009. , the Wayback Machine had saved more than 760 billion web pages. More than 350 million web pages are added daily. History The Wayback Machine began archiving cached web pages in 1996. One of the earliest known pages was saved on May 10, 1996, at 2:08p.m. Internet Archive founders Brewster Kahle and Bruce Gilliat launched the Wayback Machine in San Francisco, California, in October 2001, primarily to address the problem of web co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Archive
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, movies/videos, moving images, and millions of books. In addition to its archiving function, the Archive is an activist organization, advocating a free and open Internet. , the Internet Archive holds over 35 million books and texts, 8.5 million movies, videos and TV shows, 894 thousand software programs, 14 million audio files, 4.4 million images, 2.4 million TV clips, 241 thousand concerts, and over 734 billion web pages in the Wayback Machine. The Internet Archive allows the public to upload and download digital material to its data cluster, but the bulk of its data is collected automatically by its web crawlers, which work to preserve as much of the public web as possible. Its web archiving, web archive, the Wayback Machine, contains hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Steel Group
International Steel Group (ISG) was an American steel company, headquartered in Cleveland, Ohio, which was established by the New York investment firm WL Ross & Co LLC to acquire the assets of bankrupt steel companies and combine them together in a new company. In 2004 it was ranked #426 on the Fortune 500 list. History International Steel Group was created in 2002, after the turn-around investment fund WL Ross & Co. LLC, purchased the LTV Steel (Ling-Temco-Vought) and Acme Steel corporations. The next year, it acquired what was left of the remaining assets of the dissolved Bethlehem Steel, formerly America's second-largest steel producer, without merging. In 2005, ISG was acquired by Mittal Steel, which merged with Arcelor to become ArcelorMittal in 2006. The Luxembourg based ArcelorMittal is an integrated steel and mining multinational corporation, and is the world's largest steel producer . Timeline * 2002: ISG purchased the assets of Acme Steel, and the integrated ste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spaced Armour
Armour with two or more plates spaced a distance apart falls under the category of spaced armour. Spaced armour can be sloped or unsloped. When sloped, it reduces the penetrating power of bullets and solid shot, as after penetrating each plate projectiles tend to tumble, deflect, deform, or disintegrate; spaced armour that is not sloped is generally designed to provide protection from explosive projectiles, which detonate before reaching the primary armour. Spaced armour is used on military vehicles such as tanks and combat bulldozers. In a less common application, it is used in some spacecraft that use Whipple shields. Against kinetic penetrators The first spaced armour was used on iron and steel Battleship, warships from the mid-19th century. Between the thin outer armour of various less important parts and the thick main armour (protecting turrets, ammunition depots, boilers and turbines) were constructed storage spaces, coal or oil bunkers, and so on (Lord Nelson-class batt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sloped Armour
Sloped armour is armour that is neither in a vertical nor a horizontal position. Such angled armour is typically mounted on tanks and other armoured fighting vehicles (AFVs), as well as naval vessels such as battleships and cruisers. Sloping an armour plate makes it more difficult to penetrate by anti-tank weapons, such as armour-piercing shells ( kinetic energy penetrators) and rockets, if they follow a more or less horizontal trajectory to their target, as is often the case. The improved protection is caused by three main effects. First, a projectile hitting a plate at an angle other than 90° has to move through a greater thickness of armour, compared to hitting the same plate at a right-angle. In the latter case only the plate thickness (the normal to the surface of the armour) must be pierced. Increasing the armour slope improves, for a given plate thickness, the level of protection at the point of impact by increasing the thickness measured in the horizontal plane, the angle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slat Armour
Slat armor (or slat armour in British English), also known as bar armor, cage armor, and standoff armor, is a type of vehicle armor designed to protect against high-explosive anti-tank (HEAT) attacks, as used by anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs). Operation Slat armor takes the form of a rigid slatted metal grid fitted around key sections of the vehicle, which disrupts the shaped charge of the warhead by either crushing it, preventing optimal detonation from occurring, or by damaging the fuzing mechanism, preventing detonation outright. Although slat armor is effective against incoming missiles, it does not offer complete protection – as many as 50% of missile impacts are unimpeded by the slat design. Slat armor is more likely to be effective if the cage spacing is less than the diameter of the incoming RPG round, which is commonly 85 mm. Combat history World War II The German Wehrmacht was the first employer of cage armor duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Military Standard
A United States defense standard, often called a military standard, "MIL-STD", "MIL-SPEC", or (informally) "MilSpecs", is used to help achieve standardization objectives by the U.S. Department of Defense. Standardization is beneficial in achieving interoperability, ensuring products meet certain requirements, commonality, reliability, total cost of ownership, compatibility with logistics systems, and similar defense-related objectives. Defense standards are also used by other non-defense government organizations, technical organizations, and industry. This article discusses definitions, history, and usage of defense standards. Related documents, such as defense handbooks and defense specifications, are also addressed. Definition of document types Although the official definitions differentiate between several types of documents, all of these documents go by the general rubric of "military standard", including defense specifications, handbooks, and standards. Strictly speaking, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army
The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, clause 1 of the United States Constitution (1789). See alsTitle 10, Subtitle B, Chapter 301, Section 3001 The oldest and most senior branch of the U.S. military in order of precedence, the modern U.S. Army has its roots in the Continental Army, which was formed 14 June 1775 to fight the American Revolutionary War (1775–1783)—before the United States was established as a country. After the Revolutionary War, the Congress of the Confederation created the United States Army on 3 June 1784 to replace the disbanded Continental Army.Library of CongressJournals of the Continental Congress, Volume 27/ref> The United States Army considers itself to be a continuation of the Continental Army, and thus considers its institutional inception to be th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive Armour
Reactive armour is a type of vehicle armour that reacts in some way to the impact of a weapon to reduce the damage done to the vehicle being protected. It is most effective in protecting against shaped charges and specially hardened kinetic energy penetrators. The most common type is ''explosive reactive armour'' (ERA), but variants include ''self-limiting explosive reactive armour'' (SLERA), ''non-energetic reactive armour'' (NERA), ''non-explosive reactive armour'' (NxRA), and electric armour. NERA and NxRA modules can withstand multiple hits, unlike ERA and SLERA. A second hit in exactly the same location may potentially penetrate any of those, as the armour in that spot is compromised. Reactive armour is intended to counteract anti-tank munitions that work by piercing the armour and then either kill the crew inside, disable vital mechanical systems, or create spalling that disables the crew — or all three. Reactive armour can be defeated with multiple hits in the same pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling (metalworking)
In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness, to make the thickness uniform, and/or to impart a desired mechanical property. The concept is similar to the rolling of dough. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is known as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is known as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes... Roll stands holding pairs of rolls are grouped together into rolling mills that can quickly process metal, typically steel, into products such as structural steel (I-beams, angle stock, channel stock), bar stock, and rails. Most steel mills ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
