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Czech Hedgehog
The Czech hedgehog ( cs, rozsocháč or ') is a static anti-tank obstacle defense made of metal angle beams or I-beams (that is, lengths with an L- or Ɪ-shaped cross section). The hedgehog is very effective in keeping light to medium tanks and vehicles from penetrating a line of defense; it maintains its function even when tipped over by a nearby explosion. Although Czech hedgehogs may provide some scant cover for attacking infantry, infantry forces are generally much less effective against fortified defensive positions than mechanized units. History World War II The Czech hedgehog's name refers to its origin in Czechoslovakia. The hedgehogs were originally used on the Czech–German border by the Czechoslovak border fortifications – a massive but never-completed fortification system that was turned over to Germany in 1938 after the occupation of the Sudetenland as a consequence of the Munich Agreement. The first hedgehogs were built of reinforced concrete, with a shape s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bundesarchiv Bild 101I-719-0240-26, Pas De Calais, Atlantikwall, Panzersperren
, type = Archive , seal = , seal_size = , seal_caption = , seal_alt = , logo = Bundesarchiv-Logo.svg , logo_size = , logo_caption = , logo_alt = , image = Bundesarchiv Koblenz.jpg , image_caption = The Federal Archives in Koblenz , image_alt = , formed = , preceding1 = , preceding2 = , dissolved = , superseding1 = , superseding2 = , agency_type = , jurisdiction = , status = Active , headquarters = PotsdamerStraße156075Koblenz , coordinates = , motto = , employees = , budget = million () , chief1_name = Michael Hollmann , chief1_position = President of the Federal Archives , chief2_name = Dr. Andrea Hänger , chief2_position ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reinforced Concrete
Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low ultimate tensile strength, tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel bars (rebar) and is usually embedded passively in the concrete before the concrete sets. However, Prestressed_concrete#Post-tensioned_concrete, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion. Description Reinforcing schemes are generally designed to resist Tension (physics), tensile Stress (mechanics), stresses in particular regions of the concrete that might cause unacceptable frac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hedgerow
A hedge or hedgerow is a line of closely spaced shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate a road from adjoining fields or one field from another, and are of sufficient age to incorporate larger trees, are known as hedgerows. Often they serve as windbreaks to improve conditions for the adjacent crops, as in bocage country. When clipped and maintained, hedges are also a simple form of topiary. A hedge often operates as, and sometimes is called, a "live fence". This may either consist of individual fence posts connected with wire or other fencing material, or it may be in the form of densely planted hedges without interconnecting wire. This is common in tropical areas where low-income farmers can demarcate properties and reduce maintenance of fence posts that otherwise deteriorate rapidly. Many other benefits can be obtained depending on the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhino Tank
"Rhino tank" (initially called "Rhinoceros") was the American nickname for Allied tanks fitted with "tusks", or bocage cutting devices, during World War II. The British designation for the modifications was Prongs. In the summer of 1944, during the Battle of Normandy, Allied forces—particularly the Americans—had become bogged down fighting the Germans in the Normandy bocage. This landscape of thick, banked dirt and rock walls covered with trees and hedges proved difficult for tanks to breach. In an effort to restore battlefield mobility, various devices were invented to allow tanks to navigate the terrain. Initially the devices were manufactured in Normandy, largely from German steel-beam beach defensive devices on an ad hoc basis. Manufacture was then shifted to the United Kingdom, and vehicles were modified before being shipped to France. The devices have been credited with restoring battlefield mobility in the difficult terrain, a claim which some historians question. Bac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M5 Stuart Tank
The M3 Stuart/Light Tank M3, was an American light tank of World War II. An improved version of the tank entered service as the M5 in 1942 to be supplied to British and other Commonwealth forces under lend-lease prior to the entry of the U.S. into the war. Afterwards, it was used by U.S. and Allied forces until the end of the war. The British service name "Stuart" came from the American Civil War Confederate general J. E. B. Stuart and was used for both the M3 and the derivative M5 Light Tank. Unofficially, were also often called "Honeys" by the British, because of their smooth ride. In U.S. use, the tanks were officially known as "Light Tank M3" and "Light Tank M5". Stuarts were first used in combat in the North African campaign; about 170 were used by the British forces in Operation Crusader (18 November – 30 December 1941). Stuarts were the first American-crewed tanks in World War II to engage the enemy in tank versus tank combat when used in the Philippines in December ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M4 Sherman
} The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. It was also the basis of several other armored fighting vehicles including self-propelled artillery, tank destroyers, and armored recovery vehicles. Tens of thousands were distributed through the Lend-Lease program to the British Commonwealth and Soviet Union. The tank was named by the British after the American Civil War General William Tecumseh Sherman. The M4 Sherman evolved from the M3 Medium Tank, which for speed of development had its main armament in a side sponson mount. The M4 retained much of the previous mechanical design, but moved the main 75 mm gun into a fully traversing central turret. One feature, a one-axis gyrostabilizer, was not precise enough to allow firing when moving but did help keep the gun aimed in rou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invasion Of Normandy
Operation Overlord was the codename for the Battle of Normandy, the Allied operation that launched the successful invasion of German-occupied Western Europe during World War II. The operation was launched on 6 June 1944 (D-Day) with the Normandy landings. A 1,200-plane airborne assault preceded an amphibious assault involving more than 5,000 vessels. Nearly 160,000 troops crossed the English Channel on 6 June, and more than two million Allied troops were in France by the end of August. The decision to undertake a cross-channel invasion in 1944 was taken at the Trident Conference in Washington in May 1943. General Dwight D. Eisenhower was appointed commander of Supreme Headquarters Allied Expeditionary Force, and General Bernard Montgomery was named commander of the 21st Army Group, which comprised all the land forces involved in the invasion. The coast of Normandy of northwestern France was chosen as the site of the invasion, with the Americans assigned to land at sectors c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Wall
The Atlantic Wall (german: link=no, Atlantikwall) was an extensive system of coastal defences and fortifications built by Nazi Germany between 1942 and 1944 along the coast of continental Europe and Scandinavia as a defence against an anticipated Allied invasion of Nazi-occupied Europe from the United Kingdom, during World War II. The manning and operation of the Atlantic Wall was administratively overseen by the German Army, with some support from ''Luftwaffe'' ground forces. The ''Kriegsmarine'' (German Navy) maintained a separate coastal defence network, organised into a number of sea defence zones. Hitler ordered the construction of the fortifications in 1942 through his Führer Directive No. 40. More than half a million French workers were drafted to build it. The wall was frequently mentioned in Nazi propaganda, where its size and strength were usually exaggerated. The fortifications included colossal coastal guns, batteries, mortars, and artillery, and thousands o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M10 Highway (Russia)
The M10 "Russia" (russian: "Россия") is a federal highway in Russia connecting the country's two largest cities, Moscow and Saint Petersburg. Other than in the vicinity of Moscow and Saint Petersburg, the M10 is basically a two-lane highway (one lane for each direction), with an occasional third centre lane to allow overtaking or for left-turning traffic at intersections. History The highway Moscow - Tver - Novgorod existed even before the founding of Saint Petersburg. Along the way there were special checkpoints ( Yam) in particular Yedrovo, Valday, Yazhelbitsy, Krestsy, and Bronnitsa. The first road, long, in this area was built by order of Peter the Great from 1712 to 1746. The construction of this road was run by an office that formed for this purpose. After the completion of the road in 1755, it was transformed into the Office of the structure of public roads. It was later known as the Commission on the Roads in the State. Route Moscow to Saint Petersburg The di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urban Combat
Urban warfare is combat conducted in urban areas such as towns and cities. Urban combat differs from combat in the open at both the operational and the tactical levels. Complicating factors in urban warfare include the presence of civilians and the complexity of the urban terrain. Urban combat operations may be conducted to capitalize on strategic or tactical advantages associated with the possession or the control of a particular urban area or to deny these advantages to the enemy. Fighting in urban areas negates the advantages that one side may have over the other in armor, heavy artillery, or air support. Ambushes laid down by small groups of soldiers with handheld anti-tank weapons can destroy entire columns of modern armor (as in the First Battle of Grozny), while artillery and air support can be severely reduced if the "superior" party wants to limit civilian casualties as much as possible, but the defending party does not (or even uses civilians as human shields). Some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railroad Tie
A railroad tie, crosstie (American English), railway tie ( Canadian English) or railway sleeper ( Australian and British English) is a rectangular support for the rails in railroad tracks. Generally laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge. Railroad ties are traditionally made of wood, but prestressed concrete is now also widely used, especially in Europe and Asia. Steel ties are common on secondary lines in the UK; plastic composite ties are also employed, although far less than wood or concrete. As of January 2008, the approximate market share in North America for traditional and wood ties was 91.5%, the remainder being concrete, steel, azobé (red ironwood) and plastic composite. Tie spacing may depend on the type of tie, traffic loads and other requirements, for example 2640 concrete ties per mile on North American mainline railroads to 2112 timber ties per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
