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Pit
Pit or PIT may refer to: Structure * Ball pit, a recreation structure * Casino pit, the part of a casino which holds gaming tables * Trapping pit, pits used for hunting * Pit (motor racing), an area of a racetrack where pit stops are conducted * Trading pit, a part of a trading floor where open outcry takes place * Pit cave, a natural cave containing a vertical shaft * Mine (mining) ** Open-pit mine, surface extraction of rock or minerals ** Coal mine or pit Science and technology * Pit, an excavation on metallic surface caused by pitting corrosion * Pit, one of many indentations used to store data on a compact disc * Pit, a seed inside a fruit; for example a cherry pit * Pit (nuclear weapon), the core of an implosion weapon * Powered industrial truck, a US legal term * Programmable interval timer, a computing device * Pulsed inductive thruster, a device used in spacecraft propulsion * Pit (botany), a part of plant cell walls which allows the exchange of fluids * Pyrena, the hard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit (motor Racing)
In motorsports, a pit stop is a pause for refuelling, new tyres, repairs, mechanical adjustments, a driver change, as a penalty, or any combination of the above. These stops occur in an area called the pits, most commonly accessed via a pit lane which runs parallel to the start/finish straightaway of the track and is connected to it at each end. Along this lane is a row of garages (typically one per team or car) outside which the work is done in a ''pit box''. Pit stop work is carried out by the pit crew of up to twenty mechanics, depending on the series regulations, while the driver often waits in the vehicle (except where a driver change is involved or in motorbike racing). The term is also used generically to describe a short break in a journey. Location and terminology Depending on the circuit, the garage may be located on pit lane or in a separate area. In most series, the order of the teams' pit boxes is assigned by points standings, race results, or previous qualifyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit (nuclear Weapon)
The pit, named after the hard core found in fruits such as peaches and apricots, is the core of an implosion nuclear weapon – the fissile material and any neutron reflector or tamper bonded to it. Some weapons tested during the 1950s used pits made with U-235 alone, or in composite with plutonium, but all-plutonium pits are the smallest in diameter and have been the standard since the early 1960s. Pit designs Christy pits The pits of the first nuclear weapons were solid, with an ''urchin'' neutron initiator in their center. The Gadget and Fat Man used pits made of 6.2 kg of solid hot pressed plutonium-gallium alloy (at 400 °C and 200 MPa in steel dies – and ) half-spheres of diameter, with a internal cavity for the initiator. The Gadget's pit was electroplated with 0.13 mm of silver; the layer, however, developed blistering and the blisters had to be ground and plated with gold leaf before the test. The Fat Man pit, and those of subsequent models, were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pittsburgh
Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the List of municipalities in Pennsylvania#Municipalities, second-most populous city in Pennsylvania behind Philadelphia, and the List of United States cities by population, 68th-largest city in the U.S. with a population of 302,971 as of the 2020 United States census, 2020 census. The city anchors the Pittsburgh metropolitan area of Western Pennsylvania; its population of 2.37 million is the largest in both the Ohio Valley and Appalachia, the Pennsylvania metropolitan areas, second-largest in Pennsylvania, and the List of metropolitan statistical areas, 27th-largest in the U.S. It is the principal city of the greater Pittsburgh–New Castle–Weirton combined statistical area that extends into Ohio and West Virginia. Pitts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit Bull
Pit bull is a term used in the United States for a type of dog descended from bulldogs and terriers, while in other countries such as the United Kingdom the term is used as an abbreviation of the American Pit Bull Terrier breed. The term was first used in 1927. Within the United States the pit bull is usually considered a heterogeneous grouping that includes the breeds American Pit Bull Terrier, American Staffordshire Terrier, American Bully, Staffordshire Bull Terrier and occasionally the American Bulldog, along with any crossbred dog that shares certain physical characteristics with these breeds. In other countries including Britain, the Staffordshire Bull Terrier is not considered a pit bull. Most pit bull-type dogs descend from the British Bull and terrier, a 19th-century dog-fighting type developed from crosses between the Old English Bulldog and the Old English Terrier. Pit bull-type dogs have a controversial reputation as pets both in the United States and internationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitting Corrosion
Pitting corrosion, or pitting, is a form of extremely localized corrosion that leads to the random creation of small holes in metal. The driving power for pitting corrosion is the depassivation of a small area, which becomes anodic (oxidation reaction) while an unknown but potentially vast area becomes cathodic (reduction reaction), leading to very localized galvanic corrosion. The corrosion penetrates the mass of the metal, with a limited diffusion of ions. Another term arises, pitting factor, which is defined as the ratio of the depth of the deepest pit (resulting due to corrosion) to the average penetration, which can be calculated based on the weight loss. Development and kinetics of pitting According to Frankel (1998) who performed a review on pitting corrosion, it develops in three successive steps: (or nucleation) by breakdown of the passive film protecting the metal surface from oxidation, (2) growth of metastable pits (growing up to the micron scale and then repassiva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit (botany)
Pits are relatively thinner portions of the cell wall that adjacent cells can communicate or exchange fluid through. Pits are characteristic of cell walls with secondary layers. Generally each pit has a complementary pit opposite of it in the neighboring cell. These complementary pits are called "pit pairs". Pits are composed of three parts: the pit chamber, the pit aperture, and the pit membrane. The pit chamber is the hollow area where the secondary layers of the cell wall are absent. The pit aperture is the opening at either end of the pit chamber. The pit membrane is the primary cell wall and middle lamella, or the membrane between adjacent cell walls, at the middle of the pit chamber. The primary cell wall at the pit membrane may also have depressions similar to the pit depressions of the secondary layers. These depressions are primary pit-fields, or primary pits. In the primary pit, the primordial pit provides an interruption in the primary cell wall that the plasmodesmat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-pit Mine
Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mining differs from extractive methods that require tunnelling into the earth, such as long wall mining. Open-pit mines are used when deposits of commercially useful ore or rocks are found near the surface. It is applied to ore or rocks found at the surface because the overburden is relatively thin or the material of interest is structurally unsuitable for tunnelling (as would be the case for cinder, sand, and gravel). In contrast, minerals that have been found underground but are difficult to retrieve due to hard rock, can be reached using a form of underground mining. To create an open-pit mine, the miners must determine the information of the ore that is underground. This is done through drilling of probe holes in the ground, then plotting eac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosh Pit
Moshing (also known as slam dancing or simply slamming) is an extreme style of dancing in which participants push or slam into each other, typically performed to "aggressive" live music such as heavy metal and punk rock. Moshing usually happens in the center of the crowd, generally closer to the stage, in an area called the "mosh pit". It is intended to be energetic and full of body contact. The dance style originated in the hardcore punk scenes of California and Washington, D.C. around 1980. Through the 1980s it spread to other branches of punk rock as well as grunge and thrash metal, which exposed it to the mainstream. Since then, moshing has occasionally been performed to energetic music within a wide variety of genres, including alternative rock, EDM and hip hop, while remaining a staple in heavy metal shows. Variations of moshing exist, including "pogoing", "circle pits", and "wall of death". Dancing can be done alone as well as in groups. While moshing is seen as a fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Pit
A ball pit (originally called a ball crawl, also known as a ball pool or ball pond) is a padded box or pool filled with small colorful hollow plastic balls generally no larger than in diameter. They are typically marketed as recreation and exercise for children. They are often found at nurseries, carnivals, amusement parks, Family fun center, fun centers, fast-food restaurants, and large video arcades, frequently incorporated into larger play structures such as mazes, Playground slide, slides and jungle gyms. They may be rented for party, parties, and smaller versions are sold for home use. History Eric McMillan created the first ball pit in 1976 at SeaWorld San Diego, SeaWorld Captain Kids World in San Diego, as a result of his experience at Ontario Place. Urban legends Beginning in the late 1990s, a number of urban legends arose about children being severely injured or killed in ball pit encounters with vipers or hypodermic needles. There is no truth to these stories. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mine (mining)
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, and fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orchestra Pit
An orchestra pit is the area in a theater (usually located in a lowered area in front of the stage) in which musicians perform. Orchestral pits are utilized in forms of theatre that require music (such as opera and ballet) or in cases when incidental music is required. The conductor is typically positioned at the front of the orchestral pit facing the stage. Construction In the pit, the walls are specially designed to provide the best possible acoustics, ensuring that the sound of the orchestra flows through the entire venue without overwhelming the performance on stage. Many orchestra pits are also designed to have reasonably low decibel levels, allowing musicians to work without fears of damaging their hearing. Typically, a small platform in the pit accommodates the conductor, so that he or she can be seen by all of the musicians, who may sit in chairs or on bleachers, depending on the design of the pit. All sorts of musicians sit here, from the conductor to the bass player. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trapping Pit
Trapping pits are deep pits dug into the ground, or built from stone, in order to trap animals. European rock drawings and cave paintings reveal that red deer (''Cervus elaphus'') and elk/moose (''Alces alces'') were hunted since the Stone Age using trapping pits. Remains of trapping pits used for hunting elk, reindeer, wolves, and bears can still be found in Northern Scandinavia. These pits, which can measure up to in size and be up to several metres deep, were camouflaged with branches and leaves. They had steep sides lined with planks or masonry, making it impossible for the animal to escape once it had fallen in. When the animal had fallen into the pit, it was killed, either bled to death by sharpened sticks pointed upwards from the bottom of the pit, or in the case of pits without these sticks, dispatched by hunters waiting nearby. Some traps had a small rope enabling rodents and amphibians to escape. Pits for hunting elk, Alces alces Pits for hunting Eurasian elk (moo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
