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Frangible Bullet
Frangible bullets are intended to disintegrate into tiny particles upon target impact to minimize their penetration of other objects. Small particles are slowed more rapidly by air resistance, and are less likely to cause injury or damage to persons and objects distant from the point of bullet impact. Most frangible bullets are subject to brittle failure upon striking a hard target. This mechanism has been used to minimize the tendency of malleable lead and copper bullets to ricochet from hard targets as large, cohesive particles. Brittle failure may occur at subsonic velocity. Attempting to crimp a brittle frangible bullet into the cartridge case may break the bullet. Brittle frangible bullets may break during the self-loading cycle of semi-automatic firearms; and those fired from revolvers often break as the bullet encounters the barrel forcing cone after leaving the cylinder. Manufacturing Powder metallurgy techniques fabricate bullets from mixtures of powdered metals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frangible Bullet Stress Test
A material is said to be frangible if through deformation (engineering), deformation it tends to break up into fragments, rather than deforming elastically and retaining its cohesion as a single object. Common cracker (food), crackers are examples of frangible materials, while fresh bread, which deforms plastically, is ''not'' frangible. A structure is frangible if it breaks, distorts, or yields on impact so as to present a minimum hazard. A frangible structure is usually designed to be of minimum mass. Light poles A frangible light pole base is designed to break away when a vehicle strikes it. This lessens the risk of injury to occupants of the vehicle. Airport structures Following a Pan Am Flight 845, serious incident where an aircraft hit a donut lighting structure at San Francisco International airport, the Federal Aviation Administration, Federal Aviation Administration (FAA) instigated frangible design rules for such structures. A frangible object was defined as "an obje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swage
Swaging () is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked. The term swage may apply to the process (verb) or to a die or tool (noun) used in that process. Origin The term "swage" comes from the Old French term , meaning "decorative groove" or "ornamental moulding". Swages were originally tools used by blacksmiths to form metal into various shapes too intricate to make with a hammer alone. These have handles for holding or pegs for attaching to an anvil, and often a flat head for striking with a hammer. Swage blocks are anvil-like dies with various shapes forged into them, which are also used for forming metal. Swages called " fullers" are specific to making grooves in swords and knives. ''Swage'' is most often pronounced ( AHD format: swāj). Another (less common) pronunciation sometimes heard in the metalworking industries is (AHD forma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institute Of Standards And Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into Outline of physical science, physical science laboratory programs that include Nanotechnology, nanoscale science and technology, engineering, information technology, neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency was named the National Bureau of Standards. History Background The Articles of Confederation, ratified by the colonies in 1781, provided: The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States. Article 1, section 8, of the Constitution of the United States, ratified i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of Law Enforcement Standards
An office is a space where the employees of an organization perform administrative work in order to support and realize the various goals of the organization. The word "office" may also denote a position within an organization with specific duties attached to it (see officer or official); the latter is an earlier usage, as "office" originally referred to the location of one's duty. In its adjective form, the term "office" may refer to business-related tasks. In law, a company or organization has offices in any place where it has an official presence, even if that presence consists of a storage silo. For example, instead of a more traditional establishment with a desk and chair, an office is also an architectural and design phenomenon, including small offices, such as a bench in the corner of a small business or a room in someone's home (see small office/home office), entire floors of buildings, and massive buildings dedicated entirely to one company. In modern terms, an office i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institute Of Justice
The National Institute of Justice (NIJ) is the research, development, and evaluation agency of the United States Department of Justice (DOJ). NIJ, along with the Bureau of Justice Statistics (BJS), Bureau of Justice Assistance (BJA), Office of Juvenile Justice and Delinquency Prevention (OJJDP), Office for Victims of Crime (OVC), and other program offices, comprise the DOJ's Office of Justice Programs (OJP). History The National Institute of Law Enforcement and Criminal Justice was established on October 21, 1968, under the Omnibus Crime Control and Safe Streets Act of 1968, as a component of the Law Enforcement Assistance Administration (LEAA). In 1978, it was renamed as the National Institute of Justice. Some functions of the LEAA were absorbed by NIJ on December 27, 1979, with passage of the Justice System Improvement Act of 1979. The act, which amended the Omnibus Crime Control and Safe Streets Act of 1968, also led to creation of the Bureau of Justice Statistics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Armour
Body armour, personal armour (also spelled ''armor''), armoured suit (''armored'') or coat of armour, among others, is armour for a person's body: protective clothing or close-fitting hands-free shields designed to absorb or deflect physical attacks. Historically used to protect military personnel, today it is also used by various types of police (riot police in particular), private security guards, or bodyguards, and occasionally ordinary citizens. Today there are two main types: regular non-plated body armor for moderate to substantial protection, and hard-plate reinforced body armor for maximum protection, such as used by combatants. History Many factors have affected the development of personal armor throughout human history. Significant factors in the development of armor include the economic and technological necessities of armor production. For instance full plate armor first appeared in medieval Europe when water-powered trip hammers made the formation of plates fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialised connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralisation of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Metal Jacket Bullet
A full metal jacket (FMJ) bullet is a small-arms projectile consisting of a soft core (often lead) encased in an outer shell ("jacket") of harder metal, such as gilding metal, cupronickel, or, less commonly, a steel alloy. A bullet jacket usually allows higher muzzle velocity, muzzle velocities than bare lead without depositing significant amounts of metal in the Gun barrel, bore. It also prevents damage to bores from hard steel or armour-piercing ammunition, armor-piercing core materials. History Despite a widespread belief that the full metal jacket bullet was invented ca. 1882 by Swiss Colonel Eduard Rubin while he was working for the Swiss Federal Ammunition Factory and Research Center, in fact it was known already in the 1880s that the actual inventor was Prussian Major (later Lt.-Col.) (1835-1885), who came up with the idea either in 1875 or 1876. The use of full metal jacketing in military ammunition came about in part because of the need for improved feeding charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rimfire Ammunition
Rimfire ammunition (also rim-fire) is a type of metallic cartridge used in firearms where the primer is located within a hollow circumferential rim protruding from the base of its casing. When fired, the gun's firing pin strikes and crushes the rim against the edge of the barrel breech, sparking the primer compound within the rim and igniting the propellant within the case. Invented in 1845 by Louis-Nicolas Flobert, the first rimfire metallic cartridge was the (also known as the 6mm Flobert) cartridge, which consisted of a percussion cap with a bullet attached to the top. While many other different cartridge priming methods have been tried since the early 19th century, such as teat-fire and pinfire, only small caliber rimfire ( .22caliber (5.6mm) or less) cartridges have survived to the present day with regular use. The .22Long Rifle rimfire cartridge, introduced in 1887, is by far the most common ammunition found in the world today in terms of units manufactured and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass
Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass are named after the material, e.g., a Tumbler (glass), "glass" for drinking, "glasses" for vision correction, and a "magnifying glass". Glass is most often formed by rapid cooling (quenching) of the Melting, molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia, Ancient Egypt, Egypt, or Syria. The earliest known glass objects were beads, perhaps created accidentally during metalworking or the production of faience, which is a form of pottery using lead glazes. Due to its ease of formability int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drywall
Drywall (also called plasterboard, dry lining, wallboard, sheet rock, gib board, gypsum board, buster board, turtles board, slap board, custard board, gypsum panel and gyprock) is a panel made of calcium sulfate dihydrate (gypsum), with or without additives, typically extruded between thick sheets of facer and backer paper, used in the construction of interior walls and ceilings. The plaster is mixed with fiber (typically paper, glass wool, or a combination of these materials); plasticizer, foaming agent; and additives that can reduce mildew, flammability, and water absorption. In the mid-20th century, drywall construction became prevalent in North America as a time- and labor-saving alternative to lath and plaster. History Sackett Board was invented in 1890 by New York Coal Tar Chemical Company employees Augustine Sackett and Fred L. Kane, graduates of Rensselaer Polytechnic Institute. It was made by layering plaster within four plies of wool felt paper. Sheets were thick w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hollow-point Bullet
A hollow-point bullet is a type of expanding bullet which expands on impact with a soft target, transferring more or all of the projectile's energy into the target over a shorter distance. Hollow-point bullets are used for controlled penetration, where overpenetration could cause collateral damage (such as aboard an aircraft). In target shooting, they are used for greater accuracy due to the larger meplat. They are more accurate and predictable compared to pointed bullets which, despite having a higher ballistic coefficient (BC), are more sensitive to bullet harmonic characteristics and wind deflection. Plastic-tipped bullets are a type of (rifle) bullet meant to confer the aerodynamic advantage of the Spitzer bullet (for example, see very-low-drag bullet) and the stopping power of hollow-point bullets. Gunshot wounds from hollow-point bullets can be very painful; due to this, they have been banned from use in wartime. They may leave fragments difficult to remove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
