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Void
Void may refer to: Science, engineering, and technology * Void (astronomy), the spaces between galaxy filaments that contain no galaxies * Void (composites), a pore that remains unoccupied in a composite material * Void, synonym for vacuum, a space containing no matter * Void, a bubble within a mechanical part that causes cavitation when it collapses * Void, an unwanted air pocket formed during injection moulding * VoID or Vocabulary of Interlinked Datasets, an RDF vocabulary to enable the discovery and use of linked data sets * Void coefficient, the change in the reactivity of a nuclear reactor when voids form in moderator or coolant fluids * Void Linux, a Linux distribution * Void ratio, the volume of void-space to solid space in a material * Void safety, in object-oriented programming, a guarantee that no object references will have null values * Void type, in programming languages, a keyword indicating the absence of data * Void set or empty set, the mathematical set ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void (astronomy)
Cosmic voids (also known as dark space) are vast spaces between filaments (the largest-scale structures in the universe), which contain very few or no galaxies. The cosmological evolution of the void regions differs drastically from the evolution of the Universe as a whole: there is a long stage when the curvature term dominates, which prevents the formation of galaxy clusters and massive galaxies. Hence, although even the emptiest regions of voids contain more than ~15% of the average matter density of the Universe, the voids look almost empty for an observer. Voids typically have a diameter of 10 to 100 megaparsecs (30 to 300 million light-years); particularly large voids, defined by the absence of rich superclusters, are sometimes called supervoids. They were first discovered in 1978 in a pioneering study by Stephen Gregory and Laird A. Thompson at the Kitt Peak National Observatory. Voids are believed to have been formed by baryon acoustic oscillations in the Big Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void Coefficient
In nuclear engineering, the void coefficient (more properly called void coefficient of reactivity) is a number that can be used to estimate how much the reactivity of a nuclear reactor changes as voids (typically steam bubbles) form in the reactor moderator or coolant. Net reactivity in a reactor is the sum total of all these contributions, of which the void coefficient is but one. Reactors in which either the moderator or the coolant is a liquid typically will have a void coefficient value that is either negative (if the reactor is under-moderated) or positive (if the reactor is over-moderated). Reactors in which neither the moderator nor the coolant is a liquid (e.g., a graphite-moderated, gas-cooled reactor) will have a void coefficient value equal to zero. It is unclear how the definition of 'void' coefficient applies to reactors in which the moderator/coolant is neither liquid nor gas ( supercritical water reactor). Explanation Nuclear fission reactors run on nuclear chai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void (composites)
A void is a pore that remains unfilled with polymer and fibers in a composite material. Voids are typically the result of poor manufacturing of the material and are generally deemed undesirable. Voids can affect the mechanical properties and lifespan of the composite. They degrade mainly the matrix-dominated properties such as interlaminar shear strength, longitudinal compressive strength, and transverse tensile strength. Voids can act as crack initiation sites as well as allow moisture to penetrate the composite and contribute to the anisotropy of the composite. For aerospace applications, a void content of approximately 1% is still acceptable, while for less sensitive applications, the allowance limit is 3-5%. Although a small increase in void content may not seem to cause significant issues, a 1-3% increase in void content of carbon fiber reinforced composite can reduce the mechanical properties by up to 20% Void content in composites is represented as a ratio, also calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void Type
The void type, in several programming languages derived from C and Algol68, is the return type of a function that returns normally, but does not provide a result value to its caller. Usually such functions are called for their side effects, such as performing some task or writing to their output parameters. The usage of the void type in such context is comparable to procedures in Pascal and syntactic constructs which define subroutines in Visual Basic. It is also similar to the unit type used in functional programming languages and type theory. See Unit type#In programming languages for a comparison. C and C++ also support the pointer to void type (specified as void *), but this is an unrelated notion. Variables of this type are pointers to data of an ''unspecified'' type, so in this context (but not the others) void * acts roughly like a universal or top type. A program can probably convert a pointer to any type of data (except a function pointer) to a pointer to void ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void Linux
Void Linux is an independent Linux distribution that uses the X Binary Package System (XBPS) package manager, which was designed and implemented from scratch, and the runit init system. Excluding binary kernel blobs, a base install is composed entirely of free software (but users can access an official non-free repository to install proprietary software as well). History Void Linux was created in 2008 by Juan Romero Pardines, a former developer of NetBSD, to have a test-bed for the XBPS package manager. The ability to natively build packages from source using xbps-src is likely inspired by pkgsrc and other BSD ports collections. In May 2018, the project was moved to a new website and code repository by the core team after the project leader had not been heard from for several months. As of April 2022, Void is the third highest rated project on DistroWatch with a score of 9.09 out of 10. Features Void is a notable exception to the majority of Linux distributions because it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a ''perfect'' vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is considerably lower than atmospheric pressure. The Latin term ''in vacuo'' is used to describe an object that is surrounded by a vacuum. The ''quality'' of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. But h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void Ratio
The void ratio of a mixture is the ratio of the volume of voids to volume of solids. It is a dimensionless quantity in materials science, and is closely related to porosity as follows: :e = \frac = \frac = \frac and :\phi = \frac = \frac = \frac where e is void ratio, \phi is porosity, ''VV'' is the volume of void-space (such as fluids), ''VS'' is the volume of solids, and ''V''''T'' is the total or bulk volume. This figure is relevant in composites, in mining (particular with regard to the properties of tailings), and in soil science. In geotechnical engineering, it is considered one of the state variables of soils and represented by the symbol ''e''. Note that in geotechnical engineering, the symbol \phi usually represents the angle of shearing resistance, a shear strength (soil) parameter. Because of this, the equation is usually rewritten using n for porosity: :e = \frac = \frac = \frac and :n = \frac = \frac = \frac where e is void ratio, n is porosity, ''VV'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavitation
Cavitation is a phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock waves that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation and non-inertial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void (band)
Void was an American hardcore punk band formed in Columbia, Maryland, in 1980. The group was a pioneering force in the thriving D.C. Hardcore scene in Washington D.C. during the early 1980s, successfully combining elements of punk with heavy metal in a style that was accepted by the scene's otherwise exclusive community. Void's punk metal fusion sound was marked by guitarist Bubba Dupree's innovative guitar work and the "unhinged" vocals of John Weiffenbach, which resonated in the band's chaotic but popular live performances. Like many of their contemporaries, Void had a short-lived recording career, limited to the split album '' Faith/Void Split'' with the Faith on Dischord Records. However, they have enjoyed an enduring cult following among hardcore aficionados. History Inspired by punk rock bands the Teen Idles and Minor Threat, Void—a name which referred to Black Sabbath's song " Into the Void"—was formed in 1979, and consisted of an interracial lineup unique to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void Safety
Void safety (also known as null safety) is a guarantee within an object-oriented programming language that no object references will have ''null'' or ''void'' values. In object-oriented languages, access to objects is achieved through references (or, equivalently, pointers). A typical call is of the form: x.f(a, ...) where ''f'' denotes an operation and ''x'' denotes a reference to some object. At execution time, however, a reference can be ''void'' (or ''null''). In such cases, the call above will be a void call, leading to a run-time exception, often resulting in abnormal termination of the program. Void safety is a static (compile-time) guarantee that a void call will never arise. History In a 2009 talk, Tony Hoare traced the invention of the null pointer to his design of the ALGOL W language and called it a "mistake": Bertrand Meyer introduced the term "void safety". In programming languages An early attempt to guarantee void safety was the design of the Self progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ØØ Void
''ØØ Void'' (pronounced in interviews as "double-O void") is the first studio album by Sunn O))). The album was recorded on 24 track 2" tape at Grandmaster Studios in Hollywood, a large step forward in production values from the band's demo recording '' The Grimmrobe Demos''. The third track, "Rabbits' Revenge", is an interpretation of an obscure Melvins' song that was only played live during their early years. A sample of a live performance of the original song can be heard past the five minute mark. The album was originally released in 2000, by Hydra Head in the USA, and by Rise Above in Europe and the United Kingdom. In 2008, ''ØØ Void'' was reissued and released in Japan only, through the Japanese record label Daymare Recordings. The reissue was a two-disc set, with the first disc containing all of the original tracks from ''ØØ Void'' and the second disc containing a collaboration between Sunn O))) and the experimental/industrial group Nurse with Wound. The album wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Void Trilogy
The ''Void Trilogy'' is a space opera series by British author Peter F. Hamilton. The series is set in the same universe as The '' Commonwealth Saga'', 1,200 years after the end of '' Judas Unchained''. Peter F. Hamilton sold the American rights to the series to Random House. The series includes the following books: *''The Dreaming Void'' (2007) *''The Temporal Void'' (2008) *''The Evolutionary Void'' (2010) Synopsis ''The Dreaming Void'' What was formerly believed to be a supermassive black hole at the centre of the Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ... is revealed to be an artificial construct, known as the Void. Inside, there is a strange universe where the laws of physics are very different from those we know. It is slowly consuming the other stars o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
