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Overuse in some journals
Starting in the 2010s, some journals began questioning whether significance testing, and particularly using a threshold of =5%, was being relied on too heavily as the primary measure of validity of a hypothesis. Some journals encouraged authors to do more detailed analysis than just a statisti... | Statistical significance | Wikipedia | 479 | 160995 | https://en.wikipedia.org/wiki/Statistical%20significance | Mathematics | Statistics | null |
In logic, negation, also called the logical not or logical complement, is an operation that takes a proposition to another proposition "not ", written , , or . It is interpreted intuitively as being true when is false, and false when is true. For example, if is "Spot runs", then "not " is "Spot does not run". An o... | Negation | Wikipedia | 493 | 161019 | https://en.wikipedia.org/wiki/Negation | Mathematics | Specific functions | null |
Notation
The negation of a proposition is notated in different ways, in various contexts of discussion and fields of application. The following table documents some of these variants:
The notation is Polish notation.
In set theory, is also used to indicate 'not in the set of': is the set of all members of that a... | Negation | Wikipedia | 466 | 161019 | https://en.wikipedia.org/wiki/Negation | Mathematics | Specific functions | null |
Negations of quantifiers
In first-order logic, there are two quantifiers, one is the universal quantifier (means "for all") and the other is the existential quantifier (means "there exists"). The negation of one quantifier is the other quantifier ( and ). For example, with the predicate P as "x is mortal" and the do... | Negation | Wikipedia | 497 | 161019 | https://en.wikipedia.org/wiki/Negation | Mathematics | Specific functions | null |
The exclamation mark "!" signifies logical NOT in B, C, and languages with a C-inspired syntax such as C++, Java, JavaScript, Perl, and PHP. "NOT" is the operator used in ALGOL 60, BASIC, and languages with an ALGOL- or BASIC-inspired syntax such as Pascal, Ada, Eiffel and Seed7. Some languages (C++, Perl, etc.) provid... | Negation | Wikipedia | 404 | 161019 | https://en.wikipedia.org/wiki/Negation | Mathematics | Specific functions | null |
In C (and some other languages descended from C), double negation (!!x) is used as an idiom to convert x to a canonical Boolean, ie. an integer with a value of either 0 or 1 and no other. Although any integer other than 0 is logically true in C and 1 is not special in this regard, it is sometimes important to ensure th... | Negation | Wikipedia | 209 | 161019 | https://en.wikipedia.org/wiki/Negation | Mathematics | Specific functions | null |
A document is a written, drawn, presented, or memorialized representation of thought, often the manifestation of non-fictional, as well as fictional, content. The word originates from the Latin , which denotes a "teaching" or "lesson": the verb denotes "to teach". In the past, the word was usually used to denote writ... | Document | Wikipedia | 453 | 161228 | https://en.wikipedia.org/wiki/Document | Technology | Media and communication: Basics | null |
"Document" is defined in library and information science and documentation science as a fundamental, abstract idea: the word denotes everything that may be represented or memorialized to serve as evidence. The classic example provided by Briet is an antelope: "An antelope running wild on the plains of Africa should not... | Document | Wikipedia | 409 | 161228 | https://en.wikipedia.org/wiki/Document | Technology | Media and communication: Basics | null |
Drafting
The page layout of a document is how information is graphically arranged in the space of the document, e.g., on a page. If the appearance of the document is of concern, the page layout is generally the responsibility of a graphic designer. Typography concerns the design of letter and symbol forms and their phy... | Document | Wikipedia | 459 | 161228 | https://en.wikipedia.org/wiki/Document | Technology | Media and communication: Basics | null |
In quantum physics, a quantum fluctuation (also known as a vacuum state fluctuation or vacuum fluctuation) is the temporary random change in the amount of energy in a point in space, as prescribed by Werner Heisenberg's uncertainty principle. They are minute random fluctuations in the values of the fields which represe... | Quantum fluctuation | Wikipedia | 432 | 161253 | https://en.wikipedia.org/wiki/Quantum%20fluctuation | Physical sciences | Quantum mechanics | Physics |
These probability distributions illustrate that every possible configuration of the field is possible, with the amplitude of quantum fluctuations controlled by the Planck constant , just as the amplitude of thermal fluctuations is controlled by , where is the Boltzmann constant. Note that the following three points ar... | Quantum fluctuation | Wikipedia | 238 | 161253 | https://en.wikipedia.org/wiki/Quantum%20fluctuation | Physical sciences | Quantum mechanics | Physics |
A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical be... | Period 5 element | Wikipedia | 275 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Elements and their properties
{| class="wikitable sortable"
! colspan="3" | Chemical element
! Block
! Electron configuration
|-
!
!
!
!
!
|- bgcolor=""
|| 37 || Rb || Rubidium || s-block || [Kr] 5s1
|- bgcolor=""
|| 38 || Sr || Strontium || s-block || [Kr] 5s2
|- bgcolor=""
|| 39 || Y || Yttrium || d-block || [Kr]... | Period 5 element | Wikipedia | 502 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
|| 49 || In || Indium || p-block || [Kr] 4d10 5s2 5p1
|- bgcolor=""
|| 50 || Sn || Tin || p-block || [Kr] 4d10 5s2 5p2
|- bgcolor=""
|| 51 || Sb || Antimony || p-block || [Kr] 4d10 5s2 5p3
|- bgcolor=""
|| 52 || Te || Tellurium || p-block || [Kr] 4d10 5s2 5p4
|- bgcolor=""
|| 53 || I || Iodine || p-block || [Kr] 4d10 5... | Period 5 element | Wikipedia | 230 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
(*) Exception to the Madelung rule
s-block elements
Rubidium
Rubidium is the first element placed in period 5. It is an alkali metal, the most reactive group in the periodic table, having properties and similarities with both other alkali metals and other period 5 elements. For example, rubidium has 5 electron shel... | Period 5 element | Wikipedia | 465 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
In 1787, Carl Axel Arrhenius found a new mineral near Ytterby in Sweden and named it ytterbite, after the village. Johan Gadolin discovered yttrium's oxide in Arrhenius' sample in 1789, and Anders Gustaf Ekeberg named the new oxide yttria. Elemental yttrium was first isolated in 1828 by Friedrich Wöhler.
The most impo... | Period 5 element | Wikipedia | 443 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Niobium has physical and chemical properties similar to those of the element tantalum, and the two are therefore difficult to distinguish. The English chemist Charles Hatchett reported a new element similar to tantalum in 1801, and named it columbium. In 1809, the English chemist William Hyde Wollaston wrongly conclude... | Period 5 element | Wikipedia | 373 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Molybdenum is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores. The free element, which is a silvery metal,... | Period 5 element | Wikipedia | 468 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Its short-lived gamma ray-emitting nuclear isomer—technetium-99m—is used in nuclear medicine for a wide variety of diagnostic tests. Technetium-99 is used as a gamma ray-free source of beta particles. Long-lived technetium isotopes produced commercially are by-products of fission of uranium-235 in nuclear reactors and ... | Period 5 element | Wikipedia | 466 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
The element's major use (about 80% of world rhodium production) is as one of the catalysts in the three-way catalytic converters of automobiles. Because rhodium metal is inert against corrosion and most aggressive chemicals, and because of its rarity, rhodium is usually alloyed with platinum or palladium and applied in... | Period 5 element | Wikipedia | 422 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Ore deposits of palladium and other PGMs are rare, and the most extensive deposits have been found in the norite belt of the Bushveld Igneous Complex covering the Transvaal Basin in South Africa, the Stillwater Complex in Montana, United States, the Thunder Bay District of Ontario, Canada, and the Norilsk Complex in Ru... | Period 5 element | Wikipedia | 358 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition ... | Period 5 element | Wikipedia | 505 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Indium is not known to be used by any organism. In a similar way to aluminium salts, indium(III) ions can be toxic to the kidney when given by injection, but oral indium compounds do not have the chronic toxicity of salts of heavy metals, probably due to poor absorption in basic conditions. Radioactive indium-111 (in v... | Period 5 element | Wikipedia | 474 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
For some time China has been the largest producer of antimony and its compounds, with most production coming from the Xikuangshan Mine in Hunan. Antimony compounds are prominent additives for chlorine and bromine containing fire retardants found in many commercial and domestic products. The largest application for meta... | Period 5 element | Wikipedia | 443 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers. Iodine's relatively high atomic number, low toxicity, and ease of attachment to organic compounds have made it a part of many X-ray contrast materials in modern medicine. Iodine has only one... | Period 5 element | Wikipedia | 485 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
Molybdenum-containing enzymes are used as catalysts by some bacteria to break the chemical bond in atmospheric molecular nitrogen, allowing biological nitrogen fixation. At least 50 molybdenum-containing enzymes are now known in bacteria and animals, though only the bacterial and cyanobacterial enzymes are involved in ... | Period 5 element | Wikipedia | 495 | 161278 | https://en.wikipedia.org/wiki/Period%205%20element | Physical sciences | Periods | Chemistry |
A noble metal is ordinarily regarded as a metallic element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals (ruthenium, rhodium, palladium, osmium, iridium) are most often so classified. Silver, copper, and mercury are sometimes... | Noble metal | Wikipedia | 468 | 161291 | https://en.wikipedia.org/wiki/Noble%20metal | Physical sciences | d-Block | Chemistry |
Prior to Mendeleev's publication in 1869 of the first (eventually) widely accepted periodic table, Odling published a table in 1864, in which the "noble metals" rhodium, ruthenium, palladium; and platinum, iridium, and osmium were grouped together, and adjacent to silver and gold.
Properties
Geochemical
The noble met... | Noble metal | Wikipedia | 506 | 161291 | https://en.wikipedia.org/wiki/Noble%20metal | Physical sciences | d-Block | Chemistry |
Cs + Au -> CsAu
(Caesium Auride, a yellow crystalline salt with the ion). Platinum also exhibits similar properties with
BaPt, BaPt2, Cs2Pt (Barium and Caesium Platinides, which are reddish salts).
Electronic
The expression noble metal is sometimes confined to copper, silver, and gold since their full d-subshells ca... | Noble metal | Wikipedia | 512 | 161291 | https://en.wikipedia.org/wiki/Noble%20metal | Physical sciences | d-Block | Chemistry |
2 Ag + H2S + O2 → Ag2S + H2O.
Rayner-Canham contends that, "silver is so much more chemically-reactive and has such a different chemistry, that it should not be considered as a 'noble metal'." In dentistry, silver is not regarded as a noble metal due to its tendency to corrode in the oral environment.
The relevance o... | Noble metal | Wikipedia | 511 | 161291 | https://en.wikipedia.org/wiki/Noble%20metal | Physical sciences | d-Block | Chemistry |
"It follows from this that noble metals...have little attraction for oxygen and are consequently not oxidised or discoloured at moderate temperatures."
Such nobility is mainly associated with the relatively high electronegativity values of the noble metals, resulting in only weakly polar covalent bonding with oxygen. T... | Noble metal | Wikipedia | 169 | 161291 | https://en.wikipedia.org/wiki/Noble%20metal | Physical sciences | d-Block | Chemistry |
In chemistry, an amphoteric compound () is a molecule or ion that can react both as an acid and as a base. What exactly this can mean depends on which definitions of acids and bases are being used.
Etymology and terminology
Amphoteric is derived from the Greek word () meaning "both". Related words in acid-base chemi... | Amphoterism | Wikipedia | 489 | 161293 | https://en.wikipedia.org/wiki/Amphoterism | Physical sciences | Concepts | Chemistry |
Amphiprotic molecules
According to the Brønsted-Lowry theory of acids and bases, acids are proton donors and bases are proton acceptors. An amphiprotic molecule (or ion) can either donate or accept a proton, thus acting either as an acid or a base. Water, amino acids, hydrogencarbonate ion (or bicarbonate ion) , dihydr... | Amphoterism | Wikipedia | 464 | 161293 | https://en.wikipedia.org/wiki/Amphoterism | Physical sciences | Concepts | Chemistry |
Oxides
Zinc oxide (ZnO) reacts both with acids and with bases:
ZnO + \overset{acid}{H2SO4} -> ZnSO4 + H2O
ZnO + \overset{base}{2 NaOH} + H2O -> Na2[Zn(OH)4]
This reactivity can be used to separate different cations, for instance zinc(II), which dissolves in base, from manganese(II), which does not dissolve in base.
Le... | Amphoterism | Wikipedia | 493 | 161293 | https://en.wikipedia.org/wiki/Amphoterism | Physical sciences | Concepts | Chemistry |
Some other elements which form amphoteric oxides are gallium, indium, scandium, titanium, zirconium, chromium, iron, cobalt, copper, silver, gold, germanium, antimony, bismuth, beryllium, and tellurium.
Hydroxides
Aluminium hydroxide is also amphoteric:
Al(OH)3 + \overset{acid}{3 HCl} -> AlCl3 + 3 H2O
Al(OH)3 + \overs... | Amphoterism | Wikipedia | 245 | 161293 | https://en.wikipedia.org/wiki/Amphoterism | Physical sciences | Concepts | Chemistry |
In biology, a colony is composed of two or more conspecific individuals living in close association with, or connected to, one another. This association is usually for mutual benefit such as stronger defense or the ability to attack bigger prey.
Colonies can form in various shapes and ways depending on the organism in... | Colony (biology) | Wikipedia | 503 | 161296 | https://en.wikipedia.org/wiki/Colony%20%28biology%29 | Biology and health sciences | Ecology | Biology |
Modular organisms are those in which a genet (or genetic individual formed from a sexually-produced zygote) asexually reproduces to form genetically identical clones called ramets.
A clonal colony is when the ramets of a genet live in close proximity or are physically connected. Ramets may have all of the functions ne... | Colony (biology) | Wikipedia | 463 | 161296 | https://en.wikipedia.org/wiki/Colony%20%28biology%29 | Biology and health sciences | Ecology | Biology |
Colony ontogeny for eusocial insects
Colony ontogeny refers to the developmental process and progression of a colony. It describes the various stages and changes that occur within a colony from its initial formation to its mature state. The exact duration and dynamics of colony ontogeny can vary greatly depending on th... | Colony (biology) | Wikipedia | 435 | 161296 | https://en.wikipedia.org/wiki/Colony%20%28biology%29 | Biology and health sciences | Ecology | Biology |
Colony death
Over time, colonies may go through a senescence phase where the reproductive output declines, and the colony's overall vitality diminishes. Eventually, the colony may die off or be replaced by a new generation of reproductives. After the death of the queen in a monogyne colony, possible fates other than co... | Colony (biology) | Wikipedia | 271 | 161296 | https://en.wikipedia.org/wiki/Colony%20%28biology%29 | Biology and health sciences | Ecology | Biology |
Stripping is a physical separation process where one or more components are removed from a liquid stream by a vapor stream. In industrial applications the liquid and vapor streams can have co-current or countercurrent flows. Stripping is usually carried out in either a packed or trayed column.
Theory
Stripping works... | Stripping (chemistry) | Wikipedia | 508 | 15988913 | https://en.wikipedia.org/wiki/Stripping%20%28chemistry%29 | Physical sciences | Other separations | Chemistry |
The size of the equipment, and particularly the height and diameter, is important in determining the possibility of flow channeling that would reduce the contact area between the liquid and vapor streams. If flow channeling is suspected to be occurring, a redistribution plate is often necessary to, as the name indicate... | Stripping (chemistry) | Wikipedia | 461 | 15988913 | https://en.wikipedia.org/wiki/Stripping%20%28chemistry%29 | Physical sciences | Other separations | Chemistry |
Stripping is commonly used in industrial applications to remove harmful contaminants from waste streams. One example would be the removal of TBT and PAH contaminants from harbor soils. The soils are dredged from the bottom of contaminated harbors, mixed with water to make a slurry and then stripped with steam. The clea... | Stripping (chemistry) | Wikipedia | 150 | 15988913 | https://en.wikipedia.org/wiki/Stripping%20%28chemistry%29 | Physical sciences | Other separations | Chemistry |
Pelletizing is the process of compressing or molding a material into the shape of a pellet. A wide range of different materials are pelletized including chemicals, iron ore, animal compound feed, plastics, waste materials, and more. The process is considered an excellent option for the storage and transport of said mat... | Pelletizing | Wikipedia | 415 | 7167911 | https://en.wikipedia.org/wiki/Pelletizing | Technology | Industry: General | null |
Preparation of raw materials
Additional materials are added to the iron ore (pellet feed) to meet the requirements of the final pellets. This is done by placing the mixture in the pelletizer, which can hold different types of ores and additives, and mixing to adjust the chemical composition and the metallurgic properti... | Pelletizing | Wikipedia | 510 | 7167911 | https://en.wikipedia.org/wiki/Pelletizing | Technology | Industry: General | null |
Preparation of raw ingredients
Feed ingredients are normally first hammered to reduce the particle size of the ingredients. Ingredients are then batched, and then combined and mixed thoroughly by a feed mixer. Once the feed has been prepared to this stage the feed is ready to be pelletized.
Formation of the feed pelle... | Pelletizing | Wikipedia | 388 | 7167911 | https://en.wikipedia.org/wiki/Pelletizing | Technology | Industry: General | null |
Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2).
Occurrence
Portlandite occurs in a variety of environments. At the type location in Northern Ireland it occurs as an... | Portlandite | Wikipedia | 306 | 9320833 | https://en.wikipedia.org/wiki/Portlandite | Physical sciences | Minerals | Earth science |
A shingle beach, also known as either a cobble beach or gravel beach, is a commonly narrow beach that is composed of coarse, loose, well-rounded, and waterworn gravel, called shingle. The gravel (shingle) typically consists of smooth, spheroidal to flattened, pebbles, cobbles, and sometimes small boulders, generally in... | Shingle beach | Wikipedia | 353 | 11811193 | https://en.wikipedia.org/wiki/Shingle%20beach | Physical sciences | Oceanic and coastal landforms | Earth science |
Working set is a concept in computer science which defines the amount of memory that a process requires in a given time interval.
Definition
Peter Denning (1968) defines "the working set of information of a process at time to be the collection of information referenced by the process during the process time interval... | Working set | Wikipedia | 488 | 3007794 | https://en.wikipedia.org/wiki/Working%20set | Technology | Operating systems | null |
Implementation
The main hurdle in implementing the working set model is keeping track of the working set. The working set window is a moving window. At each memory reference a new reference appears at one end and the oldest reference drops off the other end. A page is in the working set if it is referenced in the worki... | Working set | Wikipedia | 435 | 3007794 | https://en.wikipedia.org/wiki/Working%20set | Technology | Operating systems | null |
Other resources include file handles or network sockets – for example, copying one file to another is most simply done with two file handles: one for input, one for output, and thus has a "file handle working set" size of two. If only one file handle is available, copying can still be done, but requires acquiring a fil... | Working set | Wikipedia | 161 | 3007794 | https://en.wikipedia.org/wiki/Working%20set | Technology | Operating systems | null |
A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions, but is still visible to Earth through electromagnetic radiation at other parts of the spectrum, particularly X-rays and gamma rays.
Background
Most detected neutron stars are pulsars, and emit radio-frequency electromagnetic radi... | Radio-quiet neutron star | Wikipedia | 509 | 5501614 | https://en.wikipedia.org/wiki/Radio-quiet%20neutron%20star | Physical sciences | Stellar astronomy | Astronomy |
X-ray Dim Isolated Neutron Stars
Can be classified as XDINS (X-ray Dim Isolated Neutron Stars), XTINS (X-ray Thermal Isolated Neutron Stars), XINS (X-ray Isolated Neutron Stars), TEINS (Thermally Emitting Neutron Star), INS (Isolated Neutron Stars).
Defined as thermally emitting neutron stars of high magnetic fields, ... | Radio-quiet neutron star | Wikipedia | 471 | 5501614 | https://en.wikipedia.org/wiki/Radio-quiet%20neutron%20star | Physical sciences | Stellar astronomy | Astronomy |
The Antilocapridae are a family of ruminant artiodactyls endemic to North America. Their closest extant relatives are the giraffids. Only one species, the pronghorn (Antilocapra americana), is living today; all other members of the family are extinct. The living pronghorn is a small ruminant mammal resembling an antelo... | Antilocapridae | Wikipedia | 512 | 5504707 | https://en.wikipedia.org/wiki/Antilocapridae | Biology and health sciences | Other artiodactyla | Animals |
Species
Subfamily Antilocaprinae
Tribe Antilocaprini
Genus Antilocapra
Antilocapra americana - pronghorn
A. a. americana - Common pronghorn
A. a. mexicana - Mexican pronghorn
A. a. peninsularis - Baja California pronghorn
A. a. sonoriensis - Sonoran pronghorn
A. a. oregona - Oregon pronghorn
†Antilocapra pacifica
Genus... | Antilocapridae | Wikipedia | 511 | 5504707 | https://en.wikipedia.org/wiki/Antilocapridae | Biology and health sciences | Other artiodactyla | Animals |
Genus †CosoryxCosoryx cerroensisCosoryx furcatusCosoryx ilfonensisGenus †MerriamocerosMerriamoceros coronatusGenus †Merycodus (syn. Meryceros and Submeryceros)Merycodus crucensisMerycodus hookwayiMerycodus jorakiMerycodus majorMerycodus minimusMerycodus minorMerycodus necatusMerycodus nenzelensisMerycodus prodromusMery... | Antilocapridae | Wikipedia | 221 | 5504707 | https://en.wikipedia.org/wiki/Antilocapridae | Biology and health sciences | Other artiodactyla | Animals |
A substellar object, sometimes called a substar, is an astronomical object, the mass of which is smaller than the smallest mass at which hydrogen fusion can be sustained (approximately 0.08 solar masses). This definition includes brown dwarfs and former stars similar to EF Eridani B, and can also include objects of pla... | Substellar object | Wikipedia | 486 | 13313000 | https://en.wikipedia.org/wiki/Substellar%20object | Physical sciences | Astronomy basics | Astronomy |
Classification
William Duncan MacMillan proposed in 1918 the classification of substellar objects into three categories based on their density and phase state: solid, transitional and dark (non-stellar) gaseous. Solid objects include Earth, smaller terrestrial planets and moons; with Uranus and Neptune (as well as lat... | Substellar object | Wikipedia | 201 | 13313000 | https://en.wikipedia.org/wiki/Substellar%20object | Physical sciences | Astronomy basics | Astronomy |
In chemical engineering, a vapor–liquid separator is a device used to separate a vapor–liquid mixture into its constituent phases. It can be a vertical or horizontal vessel, and can act as a 2-phase or 3-phase separator.
A vapor–liquid separator may also be referred to as a flash drum, breakpot, knock-out drum or kno... | Vapor–liquid separator | Wikipedia | 444 | 13320206 | https://en.wikipedia.org/wiki/Vapor%E2%80%93liquid%20separator | Physical sciences | Phase separations | Chemistry |
Liquid level monitoring
The separator is only effective as long as there is a vapor space inside the chamber. The separator can fail if either the mixed inlet is overwhelmed with supply material, or the liquid drain is unable to handle the volume of liquid being collected. The separator may therefore be combined with ... | Vapor–liquid separator | Wikipedia | 464 | 13320206 | https://en.wikipedia.org/wiki/Vapor%E2%80%93liquid%20separator | Physical sciences | Phase separations | Chemistry |
Some compressor types such as the scroll compressor use a continuously shrinking compression volume. Once liquid completely fills this volume the pump may either stall and overload, or the pump chamber may be warped or otherwise damaged by the fluid that can not fit into a smaller space. | Vapor–liquid separator | Wikipedia | 52 | 13320206 | https://en.wikipedia.org/wiki/Vapor%E2%80%93liquid%20separator | Physical sciences | Phase separations | Chemistry |
Praya dubia, the giant siphonophore, lives in the mesopelagic zone to bathypelagic zone at to below sea level. It has been found off the coasts around the world, from Iceland in the North Atlantic to Chile in the South Pacific.
Praya dubia is a member of the order Siphonophorae within the class Hydrozoa. With a body... | Praya dubia | Wikipedia | 455 | 14485893 | https://en.wikipedia.org/wiki/Praya%20dubia | Biology and health sciences | Cnidarians | Animals |
Due to their hydrostatic skeleton being held together by water pressure above , these animals burst when brought to the surface. The remains of Praya dubia dredged up in fishing nets resemble a blob of gelatin, which prevented their identification as a unique creature until the 19th century. In 1987, Monterey Bay Aquar... | Praya dubia | Wikipedia | 234 | 14485893 | https://en.wikipedia.org/wiki/Praya%20dubia | Biology and health sciences | Cnidarians | Animals |
In chemistry, rotamers are chemical species that differ from one another primarily due to rotations about one or more single bonds. Various arrangements of atoms in a molecule that differ by rotation about single bonds can also be referred to as different conformations. Conformers/rotamers differ little in their energ... | Rotamer | Wikipedia | 414 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
For example, butane has three conformers relating to its two methyl (CH3) groups: two gauche conformers, which have the methyls ±60° apart and are enantiomeric, and an anti conformer, where the four carbon centres are coplanar and the substituents are 180° apart (refer to free energy diagram of butane). The energy diff... | Rotamer | Wikipedia | 408 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
Three isotherms are given in the diagram depicting the equilibrium distribution of two conformers at different temperatures. At a free energy difference of 0 kcal/mol, this gives an equilibrium constant of 1, meaning that two conformers exist in a 1:1 ratio. The two have equal free energy; neither is more stable, so ne... | Rotamer | Wikipedia | 417 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
Factors contributing to the free energy of conformers
The effects of electrostatic and steric interactions of the substituents as well as orbital interactions such as hyperconjugation are responsible for the relative stability of conformers and their transition states. The contributions of these factors vary depending ... | Rotamer | Wikipedia | 371 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
Spectroscopy
Conformational dynamics can be monitored by variable temperature NMR spectroscopy. The technique applies to barriers of 8–14 kcal/mol, and species exhibiting such dynamics are often called "fluxional". For example, in cyclohexane derivatives, the two chair conformers interconvert rapidly at room temperatur... | Rotamer | Wikipedia | 391 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
The mechanism requires that the departing atoms or groups follow antiparallel trajectories. For open chain substrates this geometric prerequisite is met by at least one of the three staggered conformers. For some cyclic substrates such as cyclohexane, however, an antiparallel arrangement may not be attainable depending... | Rotamer | Wikipedia | 423 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
Alkane conformers arise from rotation around sp3 hybridised carbon–carbon sigma bonds. The smallest alkane with such a chemical bond, ethane, exists as an infinite number of conformations with respect to rotation around the C–C bond. Two of these are recognised as energy minimum (staggered conformation) and energy maxi... | Rotamer | Wikipedia | 496 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
The textbook explanation for the existence of the energy maximum for an eclipsed conformation in ethane is steric hindrance, but, with a C-C bond length of 154 pm and a Van der Waals radius for hydrogen of 120 pm, the hydrogen atoms in ethane are never in each other's way. The question of whether steric hindrance is re... | Rotamer | Wikipedia | 295 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
a torsion angle between 0° and ±90° is called syn (s)
a torsion angle between ±90° and 180° is called anti (a)
a torsion angle between 30° and 150° or between −30° and −150° is called clinal (c)
a torsion angle between 0° and ±30° or ±150° and 180° is called periplanar (p)
a torsion angle between 0° and ±30° is ca... | Rotamer | Wikipedia | 335 | 1527574 | https://en.wikipedia.org/wiki/Rotamer | Physical sciences | Stereochemistry | Chemistry |
A trip hammer, also known as a tilt hammer or helve hammer, is a massive powered hammer. Traditional uses of trip hammers include pounding, decorticating and polishing of grain in agriculture. In mining, trip hammers were used for crushing metal ores into small pieces, although a stamp mill was more usual for this. In ... | Trip hammer | Wikipedia | 401 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
Although Chinese historians assert that its origins may span as far back as the Zhou dynasty (1050 BC–221 BC), the British sinologist Joseph Needham regards the earliest texts to describe the device are the Jijiupian dictionary of 40 BC, Yang Xiong's text known as the Fangyan of 15 BC, as well as the "best statement" t... | Trip hammer | Wikipedia | 354 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
With his description, it is seen that the out-of-date Chinese term for pestle and mortar (dui, tui) would soon be replaced with the Chinese term for the water-powered trip-hammer (. The Han dynasty scholar and poet Ma Rong (79–166 AD) mentioned in one of his poems of hammers 'pounding in the water-echoing caves'. As de... | Trip hammer | Wikipedia | 476 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
The Chinese use of the cam remained confined to the horizontal type and was limited to a "small variety of machines" that included only rice hulling and much later mica-pounders, paper mills and saw mills, while fulling stocks, ore stamps or forge hammers were unknown.
Classical antiquity
The main components for wat... | Trip hammer | Wikipedia | 438 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
The widest application of trip hammers seems to have occurred in Roman mining, where ore from deep veins was first crushed into small pieces for further processing. Here, the regularity and spacing of large indentations on stone anvils indicate the use of cam-operated ore stamps, much like the devices of later medieval... | Trip hammer | Wikipedia | 361 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
Water-powered and mechanised trip hammers reappeared in medieval Europe by the 12th century. Their use was described in medieval written sources of Styria (in modern-day Austria), written in 1135 and another in 1175 AD. Medieval French sources of the years 1116 and 1249 both record the use of mechanised trip hammers us... | Trip hammer | Wikipedia | 359 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
The tilt hammer or tail helve hammer has a pivot at the centre of the helve on which it is mounted, and is lifted by pushing the opposite end to the head downwards. In practice, the head on such hammers seems to have been limited to one hundredweight (about 50 kg), but a very rapid stroke rate was possible. This made i... | Trip hammer | Wikipedia | 406 | 1527674 | https://en.wikipedia.org/wiki/Trip%20hammer | Technology | Industrial machinery | null |
Sheet metal is metal formed into thin, flat pieces, usually by an industrial process.
Thicknesses can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate, such as plate steel, a class of structural steel.
Sheet metal is available in flat p... | Sheet metal | Wikipedia | 494 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
History
Hand-hammered metal sheets have been used since ancient times for architectural purposes. Water-powered rolling mills replaced the manual process in the late 17th century. The process of flattening metal sheets required large rotating iron cylinders which pressed metal pieces into sheets. The metals suited for ... | Sheet metal | Wikipedia | 500 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
Grade 1100-H14 is commercially pure aluminium, highly chemical and weather resistant. It is ductile enough for deep drawing and weldable, but has low strength. It is commonly used in chemical processing equipment, light reflectors, and jewelry.
Grade 3003-H14 is stronger than 1100, while maintaining the same formabili... | Sheet metal | Wikipedia | 452 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
Manufacturers' Standard Gauge for Sheet Steel is based on an average density of 41.82 lb per square foot per inch thick, equivalent to . The older United States Standard Gauge is based upon 40 lb per square foot per inch thick. Gauge is defined differently for ferrous (iron-based) and non-ferrous metals (e.g. aluminiu... | Sheet metal | Wikipedia | 476 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
Drawing is a forming process in which the metal is stretched over a form or die. In deep drawing the depth of the part being made is more than half its diameter. Deep drawing is used for making automotive fuel tanks, kitchen sinks, two-piece aluminum cans, etc. Deep drawing is generally done in multiple steps called dr... | Sheet metal | Wikipedia | 494 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
Sheet metal can be cut in various ways, from hand tools called tin snips up to very large powered shears. With the advances in technology, sheet metal cutting has turned to computers for precise cutting. Many sheet metal cutting operations are based on computer numerically controlled (CNC) laser cutting or multi-tool C... | Sheet metal | Wikipedia | 332 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
This is a form of bending used to produce long, thin sheet metal parts. The machine that bends the metal is called a press brake. The lower part of the press contains a V-shaped groove called the die. The upper part of the press contains a punch that presses the sheet metal down into the v-shaped die, causing it to ben... | Sheet metal | Wikipedia | 366 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
Punching is performed by placing the sheet of metal stock between a punch and a die mounted in a press. The punch and die are made of hardened steel and are the same shape. The punch is sized to be a very close fit in the die. The press pushes the punch against and into the die with enough force to cut a hole in the st... | Sheet metal | Wikipedia | 495 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
Stamping includes a variety of operations such as punching, blanking, embossing, bending, flanging, and coining; simple or complex shapes can be formed at high production rates; tooling and equipment costs can be high, but labor costs are low.
Alternatively, the related techniques repoussé and chasing have low tooling... | Sheet metal | Wikipedia | 355 | 1528221 | https://en.wikipedia.org/wiki/Sheet%20metal | Technology | Metallurgy | null |
An aircraft fairing is a structure whose primary function is to produce a smooth outline and reduce drag.
These structures are covers for gaps and spaces between parts of an aircraft to reduce form drag and interference drag, and to improve appearance.
Types
On aircraft, fairings are commonly found on:
Belly fairing... | Aircraft fairing | Wikipedia | 421 | 1528883 | https://en.wikipedia.org/wiki/Aircraft%20fairing | Technology | Aircraft components | null |
Wing tips
Wing tips are often formed as complex shapes to reduce vortex generation and so also drag, especially at low speed.
Wheels on fixed gear aircraft
Wheel fairings are often called "wheel pants", "speed fairings" in North America or "wheel spats" or "trousers", in the United Kingdom, the latter enclosing both... | Aircraft fairing | Wikipedia | 167 | 1528883 | https://en.wikipedia.org/wiki/Aircraft%20fairing | Technology | Aircraft components | null |
Betula papyrifera (paper birch, also known as (American) white birch and canoe birch) is a short-lived species of birch native to northern North America. Paper birch is named after the tree's thin white bark, which often peels in paper-like layers from the trunk. Paper birch is often one of the first species to coloniz... | Betula papyrifera | Wikipedia | 282 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
In older trees, the bark is white, commonly brightly so, flaking in fine horizontal strips to reveal a pinkish or salmon-colored inner bark. It often has small black marks and scars. In individuals younger than five years, the bark appears a brown red color with white lenticels, making the tree much harder to distingui... | Betula papyrifera | Wikipedia | 495 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
Genetics and taxonomy
B. papyrifera hybridizes with other species within the genus Betula.
Several varieties are recognized:
B. p. var papyrifera the typical paper birch
B. p. var cordifolia the eastern paper birch (now a separate species); see Betula cordifolia
B. p. var kenaica Alaskan paper birch (also treated ... | Betula papyrifera | Wikipedia | 496 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
Betula papyrifera is a pioneer species, meaning it is often one of the first trees to grow in an area after other trees are removed by some sort of disturbance. Typical disturbances colonized by paper birch are wildfire, avalanche, or windthrow areas where the wind has blown down all trees. When it grows in these pione... | Betula papyrifera | Wikipedia | 414 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
Wildlife
Birch bark is a winter staple food for moose. The nutritional quality is poor because of the large quantities of lignin, which make digestion difficult, but is important to wintering moose because of its sheer abundance. Moose prefer paper birch over aspen, alder, and balsam poplar, but they prefer willow (Sa... | Betula papyrifera | Wikipedia | 476 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
The sap is boiled down to produce birch syrup. The raw sap contains 0.9% carbohydrates (glucose, fructose, sucrose) as compared to 2 percent to 3 percent within sugar maple sap. The sap flows later in the season than maples. Currently, only a few small-scale operations in Alaska and Yukon produce birch syrup from this ... | Betula papyrifera | Wikipedia | 432 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
Pests
Bronze birch borer is a major pest among birch species. Under repeated infestation or stress to the tree from other sources, bronze birch borers may kill the tree. The insect bores into the sapwood, beginning at the top of the tree and causing death of the tree crown. The insect has a D-shaped emergence hole whe... | Betula papyrifera | Wikipedia | 223 | 1529114 | https://en.wikipedia.org/wiki/Betula%20papyrifera | Biology and health sciences | Fagales | Plants |
In topology and related areas of mathematics, a neighbourhood (or neighborhood) is one of the basic concepts in a topological space. It is closely related to the concepts of open set and interior. Intuitively speaking, a neighbourhood of a point is a set of points containing that point where one can move some amount in... | Neighbourhood (mathematics) | Wikipedia | 499 | 1529485 | https://en.wikipedia.org/wiki/Neighbourhood%20%28mathematics%29 | Mathematics | Topology | null |
Given the set of real numbers with the usual Euclidean metric and a subset defined as
then is a neighbourhood for the set of natural numbers, but is a uniform neighbourhood of this set.
Topology from neighbourhoods
The above definition is useful if the notion of open set is already defined. There is an alternat... | Neighbourhood (mathematics) | Wikipedia | 290 | 1529485 | https://en.wikipedia.org/wiki/Neighbourhood%20%28mathematics%29 | Mathematics | Topology | null |
Aspergillus () is a genus consisting of several hundred mold species found in various climates worldwide.
Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Micheli was reminded of the shape of an aspergillum (holy water sprinkler), ... | Aspergillus | Wikipedia | 436 | 1529518 | https://en.wikipedia.org/wiki/Aspergillus | Biology and health sciences | Basics | Plants |
Aspergillus is defined as a group of conidial fungi—that is, fungi in an asexual state. Some of them, however, are known to have a teleomorph (sexual state) in the Ascomycota. With DNA evidence, all members of the genus Aspergillus are members of the phylum Ascomycota.
Members of the genus possess the ability to grow ... | Aspergillus | Wikipedia | 463 | 1529518 | https://en.wikipedia.org/wiki/Aspergillus | Biology and health sciences | Basics | Plants |
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