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Minengeschoss
A mine shell (from , "mine shot") or high-explosive, high-capacity (HEHC) in British military nomenclature, is a military explosive shell type characterized by thin (usually steel) shell walls which allow a much higher explosive content than standard high-explosive shells of the same caliber, trading a higher pressure wave effect against high-explosive shells' larger fragmentation effect and better penetration of armoured targets. Mine shells were originally developed during the mid- to late 1800s against fortresses before the introduction of rebar; reinforced fortresses had made the original use of the type obsolete around World War I, but they were given a new role against aircraft during World War II. Effect, construction and use The mine shell is a more explosive version of the common high-explosive and high-explosive fragmentation shells, relying on inflicting damage primarily through the blast (pressure wave) alone rather than the higher fragmentation but less blast pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reinforced Concrete
Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low 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 reinforcing bars (known as rebar) and is usually embedded passively in the concrete before the concrete sets. However, 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 tensile stresses in particular regions of the concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Mine
A naval mine is a self-contained explosive weapon placed in water to damage or destroy surface ships or submarines. Similar to anti-personnel mine, anti-personnel and other land mines, and unlike purpose launched naval depth charges, they are deposited and left to wait until, depending on their fuzing, they are triggered by the approach of or contact with any vessel. Naval mines can be used offensively, to hamper enemy shipping movements or lock vessels into a harbour; or defensively, to create "safe" zones protecting friendly sea lanes, harbours, and naval assets. Mines allow the minelaying force commander to concentrate warships or defensive assets in mine-free areas giving the adversary three choices: undertake a resource-intensive and time-consuming minesweeping effort, accept the casualties of challenging the minefield, or use the unmined waters where the greatest concentration of enemy firepower will be encountered. Although international law requires signatory nations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Mine
A land mine, or landmine, is an explosive weapon often concealed under or camouflaged on the ground, and designed to destroy or disable enemy targets as they pass over or near it. Land mines are divided into two types: anti-tank mines, which are designed to disable tanks or other vehicles; and anti-personnel mines, designed to injure or kill people. Land mines are typically pressure activated, exploding automatically when stepped on by a person or driven over by a vehicle, though alternative detonation mechanisms are sometimes used. A land mine may cause damage by direct blast effect, by fragments that are thrown by the blast, or by both. Land mines are typically laid throughout an area, creating a ''minefield'' which is dangerous to cross. The use of land mines is controversial because of their indiscriminate nature and their potential to remain dangerous many years after a conflict has ended, harming civilians and the economy. With pressure from a number of campaign gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fougasse (weapon)
A fougasse (, ) is an improvised mortar constructed by making a hollow in the ground or rock and filling it with explosives (originally, black powder) and projectiles. The fougasse was used by Samuel Zimmermann at AugsburgThe Origins of Military Mines', Major William C. Schneck, Engineer Bulletin July 1998 in the sixteenth century, referred to by Vauban in the seventeenth century, and well known to military engineers by the mid-eighteenth century. This technique was used in several European wars, the American Revolution, and the American Civil War. The term is still used to describe such devices. Firing The normal method of firing was to use a burning torch or slow match to ignite a ''saucisson'' (French for "sausage", a cloth or leather tube waterproofed with pitch and filled with black powder) leading to the main charge. This had numerous disadvantages; the firer was obvious to the attacking enemy, and had to run to get clear after lighting the fuse. The black powder was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battle Of The Crater
The Battle of the Crater took place during the American Civil War, part of the Siege of Petersburg. It occurred on Saturday, July 30, 1864, between the Confederate Army of Northern Virginia, commanded by General Robert E. Lee, and the Union Army of the Potomac, commanded by Major General George G. Meade (under the direct supervision of the general-in-chief, Lieutenant General Ulysses S. Grant). After weeks of preparation, on July 30 Union forces exploded a mine across from Union Major General Ambrose E. Burnside's IX Corps sector, blowing a gap in the Confederate defenses of Petersburg, Virginia. Instead of being a decisive advantage to the Union, this precipitated a rapid deterioration in the Union position. Unit after unit charged into and around the crater, where most of the soldiers milled in confusion in the bottom of the crater. Grant considered this failed assault as "the saddest affair I have witnessed in this war." The Confederates quickly recovered, and launche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Warfare
Tunnel warfare refers to aspects of warfare relating to tunnels and other underground cavities. It includes the construction of underground facilities in order to attack or defend, and the use of existing natural caves and artificial underground facilities for military purposes. Tunnels can be used to undermine fortifications and slip into enemy territory for a surprise attack, while it can strengthen a defense by creating the possibility of ambush, counterattack and the ability to transfer troops from one portion of the battleground to another unseen and protected. Tunnels can serve as shelter from enemy attack. Since antiquity, sappers have used mining against walled cites, fortresses, castles or other strongly held and fortified military positions. Defenders have dug counter-mines to attack miners or destroy a mine threatening their fortifications. Since tunnels are commonplace in urban areas, tunnel warfare is often a feature, though usually a minor one, of urban warfare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Civil War
The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of America, Confederacy ("the South"), which was formed in 1861 by U.S. state, states that had Secession in the United States, seceded from the Union. The Origins of the American Civil War, central conflict leading to war was a dispute over whether Slavery in the United States, slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction. Timeline of events leading to the American Civil War, Decades of controversy over slavery came to a head when Abraham Lincoln, who opposed slavery's expansion, won the 1860 presidential election. Seven Southern slave states responded to Lincoln's victory by seceding f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blowback (firearms)
Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gas created by the ignition of the propellant charge. Several blowback systems exist within this broad principle of operation, each distinguished by the methods used to control bolt movement. In most actions that use blowback operation, the breech is not locked mechanically at the time of firing: the inertia of the bolt and recoil , relative to the weight of the bullet, delay opening of the breech until the bullet has left the barrel. A few locked breech designs use a form of blowback (example: primer actuation) to perform the unlocking function. The blowback principle may be considered a simplified form of gas operation, since the cartridge case behaves like a piston driven by the powder gases. Other operating principles for self-loading firearms include delayed blowback, blow forward, gas operation, and recoil op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recoil Operated
Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, for according to Newton's third law the force required to accelerate something will evoke an equal but opposite reactional force, which means the forward momentum gained by the projectile and exhaust gases (ejectae) will be mathematically balanced out by an equal and opposite momentum exerted back upon the gun. Basics Any launching system (weapon or not) generates recoil. However recoil only constitutes a problem in the field of artillery and firearms due to the magnitude of the forces at play. Gun chamber pressures and projectile acceleration forces are tremendous, on the order of tens to hundreds mega pascalAs a perspective, the atmospheric pressure is roughly 0.1 megapascal. and tens of thousands of times the acceleration of gravity (g's), both necessary to launch the projectile at u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nordisk Familjebok
(, 'Nordic Family Book') is a Swedish language, Swedish encyclopedia that was published in print from between 1876 and 1993, and that is now fully available in digital form via Project Runeberg at Linköping University. The public domain editions of the encyclopedia remain important reference works in Finland, especially on Finnish Wikipedia. History First edition began when Halmstad publisher hired an editor, linguist , in 1874 to publish a six-volume encyclopedia. Linder drew up a plan for the work, designed the editorial team and created a large circle of experts and literary figures, who submitted article proposals and wrote and reviewed them. Under Linder's direction, the articles were then edited to make them as formal, consistent and accurate as possible. Much attention was paid to Nordic subjects, mainly Swedish and Finnish, where sources and models were often lacking, so extensive and time-consuming pioneering work had to be done. As a result, the earlier plan f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Skin
The skin of an aircraft is the outer surface which covers much of its wings and fuselage. The most commonly used materials are aluminum and aluminium alloys with other metals, including zinc, magnesium and copper. See also *Index of aviation articles Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Articles related to aviation include: A Aviation accidents and incidents – Above Mean Sea Level (AMSL) – ADF – Acces ... References Aircraft components {{component-aircraft-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
