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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 (typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frangible Bullet Stress Test
A material is said to be frangible if through deformation it tends to break up into fragments, rather than deforming elastically and retaining its cohesion as a single object. Common 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 frangible and 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. Frangible supports are also used for airport approach structures. Bullets A frangible bullet is one that is designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the danger behind the intended target. Examples are the Glaser Safety Slug and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sintering
Clinker nodules produced by sintering Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms in the materials diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece. Because the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points such as tungsten and molybdenum. The study of sintering in metallurgical powder-related processes is known as powder metallurgy. An example of sintering can be observed when ice cubes in a glass of water adhere to each other, which is driven by the temperature difference between the water and the ice. Examples of pressure-driven sintering are the compact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel Target
Steel targets are shooting targets made out of hardened (martensitic) steel, and are used in firearm and airgun sports such as silhouette shooting, cowboy action shooting, practical/dynamic shooting, long range shooting and field target, as well as recreational plinking. They are popular in both training and competitions because the shooter gets instant acoustic feedback on a successful impact, and can often also visually confirm hits by seeing the bullet getting pulverized, leaving a mark on the surface paint, or moving/knocking down the target. Hanging steel plates (colloquially called "gongs") or self-resetting steel targets also have the advantage that the shooter does not need to go forward downrange to tape the targets, making it a good option for shooting ranges that otherwise have electronic targets. Steel targets also are weatherproof, contrary to paper targets, which do not hold up in rain and wind gusts. Precautions regarding ricochets If correct precautions are ... [...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 physical science laboratory programs that include 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 in 1789, granted these powers to the new Congr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of Law Enforcement Standards
An office is a space where an organization's employees perform administrative work in order to support and realize objects and goals of the organization. The word "office" may also denote a position within an organization with specific duties attached to it (see officer, office-holder, official); the latter is in fact an earlier usage, office as place originally referring to the location of one's duty. When used as an adjective, 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 (for example) a storage silo rather than an establishment with desk-and- chair. An office is also an architectural and design phenomenon: ranging from a small office such as a bench in the corner of a small business of extremely small size (see small office/home office), through entire floors of buildings, up to and including massive buildings dedicated entirely ... [...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. 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 Office of Justice Programs (OJP) branch of the Department of Justice. 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 Justi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Armor
Body armor, also known as body armour, personal armor or armour, or a suit or coat of armor, is protective clothing 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 civilians. 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 combat soldiers. 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 faster and cheaper. At times the development of armor has run parallel to the develop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provide structure and support for the body, and enable animal locomotion, 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 Function (biology), functions. Bone tissue (osseous tissue), which is also called bone in the mass noun, uncountable sense of that word, is hard tissue, a type of specialized connective tissue. It has a honeycomb-like matrix (biology), 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 mineralization (biology), mineralization of bone; osteoclasts are involved in the bone resorption, resor ... [...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 velocities than bare lead without depositing significant amounts of metal in the bore. It also prevents damage to bores from hard steel or armor-piercing core materials. History The bullet was invented in 1882 by Swiss Colonel Eduard Rubin while he was working for the Swiss Federal Ammunition Factory and Research Center, which developed ammunition for the Swiss military. The use of full metal jacketing in military ammunition came about in part because of the need for improved feeding characteristics in small arms that used internal mechanical manipulation of the cartridge in order to chamber rounds as opposed to externally hand-reloading single-shot firearms. The harder metal used in bullet jackets was less pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rimfire Ammunition
Rimfire ammunition is a type of firearm metallic cartridge whose primer is located within a hollow circumferential rim protruding from the base of its casing. When fired, the gun's firing pin will strike and crush the rim against the edge of the barrel breech, sparking the primer compound within the rim, and in turn ignite the propellant within the case. Invented in 1845, by Louis-Nicolas Flobert, the first rimfire metallic cartridge was the .22 BB Cap (a.k.a. 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 19th century, only rimfire and the later centerfire cartridges survive to the present day with regular usages. The .22 Long Rifle rimfire cartridge, introduced in 1887, is by far the most common ammunition in the world today in terms of units sold. Characteristics Rimfire ammunition is so named because the firing pin strikes and crushes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of the molten form; some glasses such as volcanic glass are naturally occurring. The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound silica (silicon dioxide, or quartz), the primary constituent of sand. Soda–lime glass, containing around 70% silica, accounts for around 90% of manufactured glass. The term ''glass'', in popular usage, is often used to refer only to this type of material, although silica-free glasses often have desirable properties for applications in modern communications technology. Some objects, such as drinking glasses and eyeglasses, are so commonly made of silicate-based glass that they are simply called by the name of the material. Despite bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drywall
Drywall (also called plasterboard, dry lining, wallboard, sheet rock, gypsum board, buster board, custard board, and gypsum panel) 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 middle of the 20th century, drywall construction became prevalent in North America as a time- and labor-saving alternative to lath and plaster. History The first plasterboard plant in the UK was opened in 1888 in Rochester, Kent. Sackett Board was invented in 1894 by Augustine Sackett and Fred Kane, graduates of Rensselaer Polytechnic Institute. It was made by layering plaster within four plies of wool felt paper. Sheets were thick with o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
