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A polyploid complex , also called a diploid-polyploid complex , is a group of interrelated and interbreeding species that also have differing levels of ploidy that can allow interbreeding .
A polyploid complex was described by E. B. Babcock and G. Ledyard Stebbins in their 1938 monograph The American Species of Crepis... | https://en.wikipedia.org/wiki/Polyploid_complex |
Polyprenols are natural long-chain isoprenoid alcohols of the general formula H-(C 5 H 8 )n-OH, where n is the number of isoprene units. Any prenol with more than 4 isoprene units is a polyprenol. Polyprenols play an important function, acting as natural bioregulators and are found in small quantities in various plant ... | https://en.wikipedia.org/wiki/Polyprenol |
The polypyrimidine tract is a region of pre-messenger RNA (mRNA) that promotes the assembly of the spliceosome , the protein complex specialized for carrying out RNA splicing during the process of post-transcriptional modification . The region is rich with pyrimidine nucleotides , especially uracil , and is usually 15–... | https://en.wikipedia.org/wiki/Polypyrimidine_tract |
Polypyrrole ( PPy ) is an organic polymer obtained by oxidative polymerization of pyrrole . It is a solid with the formula H(C 4 H 2 NH) n H. It is an intrinsically conducting polymer , used in electronics, optical, biological and medical fields. [ 2 ] [ 3 ]
Some of the first examples of PPy were reported in 1919 by ... | https://en.wikipedia.org/wiki/Polypyrrole |
Polyquaternium is the International Nomenclature for Cosmetic Ingredients designation for several polycationic polymers that are used in the personal care industry. Polyquaternium is a neologism used to emphasize the presence of quaternary ammonium centers in the polymer. INCI has approved at least 40 different polymer... | https://en.wikipedia.org/wiki/Polyquaternium |
Polyrotaxane is a type of mechanically interlocked molecule consisting of strings and rings, in which multiple rings are threaded onto a molecular axle and prevented from dethreading by two bulky end groups. As oligomeric or polymeric species of rotaxanes , polyrotaxanes are also capable of converting energy input to m... | https://en.wikipedia.org/wiki/Polyrotaxane |
Polysaccharides ( / ˌ p ɒ l i ˈ s æ k ə r aɪ d / ), or polycarbohydrates , are the most abundant carbohydrates found in food . They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages . This carbohydrate can react with water ( hydrolysis ) using amylase enzymes ... | https://en.wikipedia.org/wiki/Polysaccharide |
Polysialic acid is an unusual posttranslational modification that occurs on neural cell adhesion molecules (NCAM). Polysialic acid is considerably anionic . This strong negative charge gives this modification the ability to change the protein's surface charge and binding ability. In the synapse , polysialation of NCAM ... | https://en.wikipedia.org/wiki/Polysialic_acid |
Polysiphonous describes an algal branch with axial cells each surrounded by cells of the same length as the axial cells. [ 1 ]
This alga -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Polysiphonous |
In crystallography , the term polysome is used to describe overall mineral structures which have structurally and compositionally different framework structures.
A general example is amphiboles , in which cutting along the {010} plane yields alternating layers of pyroxene and trioctahedral mica . [ 1 ]
This crystallo... | https://en.wikipedia.org/wiki/Polysome_(crystallography) |
Polysome profiling is a technique in molecular biology that is used to study the association of mRNAs with ribosomes . It is different from ribosome profiling . Both techniques have been reviewed [ 1 ] and both are used in analysis of the translatome , but the data they generate are at very different levels of specific... | https://en.wikipedia.org/wiki/Polysome_profiling |
Polysorbates are a class of emulsifiers used in some pharmaceuticals and food preparation. They are commonly used in oral and topical pharmaceutical dosage forms. They are also often used in cosmetics to solubilize essential oils into water-based products. Polysorbates are oily liquids derived from ethoxylated sorbitan... | https://en.wikipedia.org/wiki/Polysorbate |
In biology, polyspermy describes the fertilization of an egg by more than one sperm . Diploid organisms normally contain two copies of each chromosome , one from each parent. The cell resulting from polyspermy, on the other hand, contains three or more copies of each chromosome—one from the egg and one each from multip... | https://en.wikipedia.org/wiki/Polyspermy |
Polysporangiophytes , also called polysporangiates or formally Polysporangiophyta , are plants in which the spore-bearing generation ( sporophyte ) has branching stems (axes) that bear sporangia . The name literally means 'many sporangia plant'. The clade includes all land plants ( embryophytes ) except for the bryophy... | https://en.wikipedia.org/wiki/Polysporangiophyte |
Polystannanes are organotin compounds with the formula (R 2 Sn) n . These polymers have been of intermittent academic interest; they are unusual because heavy elements comprise the backbone. Structurally related but better characterized (and more useful) are the polysilanes (R 2 Si) n .
Oligo- or polystannanes were f... | https://en.wikipedia.org/wiki/Polystannane |
Polysuccinimide (PSI), also known as polyanhydroaspartic acid or polyaspartimide , is formed during the thermal polycondensation of aspartic acid and is the simplest polyimide . [ 5 ] Polysuccinimide is insoluble in water, but soluble in some aprotic dipolar solvents . Its reactive nature makes polysuccinimide a versat... | https://en.wikipedia.org/wiki/Polysuccinimide |
Polysulfides are a class of chemical compounds derived from anionic chains of sulfur atoms. [ 1 ] There are two main classes of polysulfides: inorganic and organic. The inorganic polysulfides have the general formula S 2− n . These anions are the conjugate bases of polysulfanes H 2 S n . Organic polysulfides generally ... | https://en.wikipedia.org/wiki/Polysulfide |
Polysulfobetaines are zwitterionic polymers that contain a positively charged quaternary ammonium and a negatively charged sulfonate group within one constitutional repeat unit . [ 1 ] [ 2 ] In recent years, polysulfobetaines have received increasing attention owing to their good biotolerance and ultralow-fouling behav... | https://en.wikipedia.org/wiki/Polysulfobetaine |
Polysulfones are a family of high performance thermoplastics . These polymers are known for their toughness and stability at high temperatures. Technically used polysulfones contain an aryl - SO 2 -aryl subunit. Due to the high cost of raw materials and processing, polysulfones are used in specialty applications and of... | https://en.wikipedia.org/wiki/Polysulfone |
A polysyllogism is a complex argument (also known as chain arguments of which there are four kinds: polysyllogisms , sorites , epicheirema , and dilemmas ) [ 1 ] that strings together any number of propositions forming together a sequence of syllogisms such that the conclusion of each syllogism, together with the next ... | https://en.wikipedia.org/wiki/Polysyllogism |
Polytetrahedron is a term used for three distinct types of objects, all based
on the tetrahedron :
This 4-polytope article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Polytetrahedron |
Polythiazyl ( polymeric sulfur nitride ), (SN) x , is an electrically conductive , gold- or bronze-colored polymer with metallic luster . It was the first conductive inorganic polymer discovered [ 1 ] [ 2 ] and was also found to be a superconductor at very low temperatures (below 0.26 K). [ 3 ] [ 4 ] It is a fibrous so... | https://en.wikipedia.org/wiki/Polythiazyl |
Polythiophenes (PTs) are polymerized thiophenes , a sulfur heterocycle . The parent PT is an insoluble colored solid with the formula (C 4 H 2 S) n . [ notes 1 ] [ 2 ] [ 3 ] The rings are linked through the 2- and 5-positions. Poly(alkylthiophene)s have alkyl substituents at the 3- or 4-position(s). They are also col... | https://en.wikipedia.org/wiki/Polythiophene |
An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. [ 1 ] [ 2 ] A tree that contains any multifurcations can be described as a multifur... | https://en.wikipedia.org/wiki/Polytomy |
In general topology , a polytopological space consists of a set X {\displaystyle X} together with a family { τ i } i ∈ I {\displaystyle \{\tau _{i}\}_{i\in I}} of topologies on X {\displaystyle X} that is linearly ordered by the inclusion relation where I {\displaystyle I} is an arbitrary index set . It is usually assu... | https://en.wikipedia.org/wiki/Polytopological_space |
In astrophysics , a polytrope refers to a solution of the Lane–Emden equation in which the pressure depends upon the density in the form P = K ρ ( n + 1 ) / n = K ρ 1 + 1 / n , {\displaystyle P=K\rho ^{(n+1)/n}=K\rho ^{1+1/n},} where P is pressure, ρ is density and K is a constant of proportionality . [ 1 ] The constan... | https://en.wikipedia.org/wiki/Polytrope |
Polyunsaturated aldehydes ( PUAs ) are a group of allelopathic chemicals typically associated with predator–prey interactions between diatoms (a type of single-celled alga ) and small crustaceans known as copepods . [ 1 ] These compounds are classified by an aldehyde group covalently bound to long carbon chains contain... | https://en.wikipedia.org/wiki/Polyunsaturated_aldehyde |
Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and an amine component. The isocyanate can be aromatic or aliphatic in nature. It can be monomer , polymer , or any variant reaction of isocyanates, quasi-prepolymer or a prepolymer . The prepolymer, or quasi-prepolymer... | https://en.wikipedia.org/wiki/Polyurea |
Polyurethane ( / ˌ p ɒ l i ˈ jʊər ə ˌ θ eɪ n , - j ʊəˈr ɛ θ eɪ n / ; [ 1 ] often abbreviated PUR and PU ) is a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene , polyurethane term does not refer to the single type... | https://en.wikipedia.org/wiki/Polyurethane |
Polyurethane dispersion , or PUD , is understood to be a polyurethane polymer resin dispersed in water , rather than a solvent , although some cosolvent may be used. Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG ( polyethylene glycol ) inco... | https://en.wikipedia.org/wiki/Polyurethane_dispersion |
Polyurethane foam is a solid polymeric foam based on polyurethane chemistry. As a specialist synthetic material with highly diverse applications, polyurethane foams are primarily used for thermal insulation and as a cushioning material in mattresses, upholstered furniture or as seating in vehicles. Its low density and ... | https://en.wikipedia.org/wiki/Polyurethane_foam |
In chemistry , polyvalency (or polyvalence , multivalency ) is the property of molecules and larger species, such as antibodies , medical drugs, and even nanoparticles surface-functionalized with ligands, like spherical nucleic acids , that exhibit more than one supramolecular interaction . [ 1 ] [ 2 ] [ 3 ] For the nu... | https://en.wikipedia.org/wiki/Polyvalency_(chemistry) |
Polyvinyl alcohol ( PVOH , PVA , or PVAl ) is a water - soluble synthetic polymer . It has the idealized formula [CH 2 CH(OH)] n . It is used in papermaking , textile warp sizing , as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) adhesive formulations, in a variety of coatings, and 3D printing . It is... | https://en.wikipedia.org/wiki/Polyvinyl_alcohol |
Polyvinyl nitrate (abbreviated: PVN) is a high-energy polymer with the idealized formula of [CH 2 CH(ONO 2 )]. Polyvinyl nitrate is a long carbon chain (polymer) with nitrate groups ( − O − NO 2 ) {\displaystyle {\ce {(-O-NO2)}}} bonded randomly along the chain. PVN is a white, fibrous solid, and is soluble in polar or... | https://en.wikipedia.org/wiki/Polyvinyl_nitrate |
Polyvinyl siloxane ( PVS ), also called poly-vinyl siloxane , vinyl polysiloxane ( VPS ), or vinylpolysiloxane , is an addition-reaction silicone elastomer (an addition silicone). It is a viscous liquid that cures (solidifies) quickly into a rubber-like solid, taking the shape of whatever surface it was lying against w... | https://en.wikipedia.org/wiki/Polyvinyl_siloxane |
Polyvinylcarbazole ( PVK ) is a temperature-resistant [ 2 ] thermoplastic polymer produced by radical polymerization from the monomer N -vinylcarbazole . It is a photoconductive polymer and thus the basis for photorefractive polymers and organic light-emitting diodes . [ 3 ]
Polyvinylcarbazole was discovered by the ch... | https://en.wikipedia.org/wiki/Polyvinylcarbazole |
Polywater was a hypothesized polymerized form of water that was the subject of much scientific controversy during the late 1960s, first described by Soviet scientist Nikolai Fedyakin. By 1969 the popular press had taken notice of Western attempts to recreate the substance and sparked fears of a "polywater gap" between ... | https://en.wikipedia.org/wiki/Polywater |
Polyworld is a cross-platform ( Linux , Mac OS X ) program written by Larry Yaeger to evolve Artificial Intelligence through natural selection and evolutionary algorithms .
It uses the Qt graphics toolkit and OpenGL to display a graphical environment in which a population of trapezoid agents search for food, mate, hav... | https://en.wikipedia.org/wiki/Polyworld |
A polyyne is any organic compound with alternating single and triple bonds ; that is, a series of consecutive alkynes , (−C≡C−) n with n greater than 1. These compounds are also called polyacetylenes , especially in the natural products and chemical ecology literature, [ 1 ] even though this nomenclature more properly ... | https://en.wikipedia.org/wiki/Polyyne |
In the theory of dynamical systems (or turbulent flow ), the Pomeau –Manneville scenario is the transition to chaos (turbulence) due to intermittency . [ 1 ] [ 2 ] Named after Yves Pomeau and Paul Manneville . The aforementioned scenario is realized using the Pomeau–Manneville map. The Pomeau–Manneville map is a polyno... | https://en.wikipedia.org/wiki/Pomeau–Manneville_scenario |
The Pomeranz–Fritsch reaction , also named Pomeranz–Fritsch cyclization , is a named reaction in organic chemistry. It is named after Paul Fritsch (1859–1913) and Cäsar Pomeranz (1860–1926). [ 1 ] [ 2 ] In general it is a synthesis of isoquinoline . [ 2 ] [ 3 ] [ 4 ]
The reaction below shows the acid-promoted synthes... | https://en.wikipedia.org/wiki/Pomeranz–Fritsch_reaction |
Pomology (from Latin pomum , " fruit ", + -logy , "study") is a branch of botany that studies fruits and their cultivation . Someone who researches and practices the science of pomology is called a pomologist . The term fruticulture (from Latin fructus , "fruit", + cultura , "care") is also used to describe the agricul... | https://en.wikipedia.org/wiki/Pomology |
Pompeiu's theorem is a result of plane geometry , discovered by the Romanian mathematician Dimitrie Pompeiu . The theorem is simple, but not classical. It states the following:
The proof is quick. Consider a rotation of 60° about the point B . Assume A maps to C , and P maps to P '. Then P B = P ′ B {\displaystyle ... | https://en.wikipedia.org/wiki/Pompeiu's_theorem |
In mathematics , the Pompeiu problem is a conjecture in integral geometry , named for Dimitrie Pompeiu , who posed the problem in 1929,
as follows. Suppose f is a nonzero continuous function defined on a Euclidean space, and K is a simply connected Lipschitz domain , so that the integral of f vanishes on every congru... | https://en.wikipedia.org/wiki/Pompeiu_problem |
Ponceau S , Acid Red 112 , or C.I. 27195 ( systematic name : 3-hydroxy-4-(2-sulfo-4-[4-sulfophenylazo]phenylazo)-2,7-naphthalenedisulfonic acid sodium salt [ 1 ] ) is a sodium salt of a diazo dye of a light red color, that may be used to prepare a stain for rapid reversible detection of protein bands on nitrocellulose ... | https://en.wikipedia.org/wiki/Ponceau_S |
In civil engineering , ponding is the (typically) unwanted pooling of water, typically on a flat roof or roadway. Ponding water accelerates the deterioration of many materials, including seam adhesives in single-ply roof systems, steel equipment supports, and particularly roofing asphalt . On low-slope asphalt roofs, p... | https://en.wikipedia.org/wiki/Ponding |
Ponsse Plc ( Finnish : Ponsse Oyj ) [ 2 ] is a company domiciled in Finland that manufactures and markets a range of forestry vehicles and machinery such as forwarders and harvesters . The Ponsse company was established by the forest machine entrepreneur Einari Vidgrén [ fi ] in 1970. As of 2019 [update] , Ponsse's mac... | https://en.wikipedia.org/wiki/Ponsse |
In mathematics, Pontryagin duality is a duality between locally compact abelian groups that allows generalizing Fourier transform to all such groups, which include the circle group (the multiplicative group of complex numbers of modulus one), the finite abelian groups (with the discrete topology ), and the additive gro... | https://en.wikipedia.org/wiki/Pontryagin_duality |
A pony wall is a short wall.
In different circumstances, it may refer to:
This architectural element –related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Pony_wall |
In solid-state physics , the Poole–Frenkel effect (also known as Frenkel–Poole emission [ 1 ] ) is a model describing the mechanism of trap-assisted electron transport in an electrical insulator . It is named after Yakov Frenkel , who published on it in 1938, [ 2 ] extending the theory previously developed by H. H. Poo... | https://en.wikipedia.org/wiki/Poole–Frenkel_effect |
Pop-up satellite archival tags ( PSATs ) are used to track movements of (usually large, migratory) marine animals. A PSAT (also commonly referred to as a PAT tag) is an archival tag (or data logger ) that is equipped with a means to transmit the collected data via the Argos satellite system . Though the data are physi... | https://en.wikipedia.org/wiki/Pop-up_satellite_archival_tag |
A pop filter , pop shield or pop screen is a noise protection filter for microphones , typically used in a recording studio . It serves to reduce or eliminate popping sounds caused by the mechanical impact of fast-moving air on the microphone from plosives during recorded speech and singing. Pop filters can also keep s... | https://en.wikipedia.org/wiki/Pop_filter |
A Pople diagram or Pople's Diagram is a diagram which describes the relationship between various calculation methods in computational chemistry . It was initially introduced in January 1965 by Sir John Pople , KBE FRS , during the Symposium of Atomic and Molecular Quantum Theory in Florida . [ 1 ] The Pople Diagram can... | https://en.wikipedia.org/wiki/Pople_diagram |
The Pople notation is named after the Nobel laureate John Pople and is a simple method of presenting second-order spin coupling systems in NMR . [ 1 ]
The notation labels each (NMR active) nucleus with a letter of the alphabet. The difference in chemical shift , δ, relative to the J-coupling between nuclei mirrors the... | https://en.wikipedia.org/wiki/Pople_notation |
In convex analysis , Popoviciu's inequality is an inequality about convex functions . It is similar to Jensen's inequality and was found in 1965 by Tiberiu Popoviciu , [ 1 ] [ 2 ] a Romanian mathematician.
Let f be a function from an interval I ⊆ R {\displaystyle I\subseteq \mathbb {R} } to R {\displaystyle \mathbb {R... | https://en.wikipedia.org/wiki/Popoviciu's_inequality |
Structural Assessment
Seismic Retrofit Design
Geotechnical Design
Site Monitoring
Project Management
Popp & Asociații is a professional services company based in Bucharest , Romania . It provides structural design & assessment, consultancy, retrofitting design, and project management services for all aspects of th... | https://en.wikipedia.org/wiki/Popp_&_Asociații |
A poppy is a flowering plant in the subfamily Papaveroideae of the family Papaveraceae . Poppies are herbaceous plants , often grown for their colourful flowers. One species of poppy, Papaver somniferum , is the source of the narcotic drug mixture opium , which contains powerful medicinal alkaloids such as morphine and... | https://en.wikipedia.org/wiki/Poppy |
In physics , the poppy-seed bagel theorem concerns interacting particles (e.g., electrons ) confined to a bounded surface (or body) A {\displaystyle A} when the particles repel each other pairwise with a magnitude that is proportional to the inverse distance between them raised to some positive power s {\displaystyle s... | https://en.wikipedia.org/wiki/Poppy-seed_bagel_theorem |
Popular Astronomy is an American magazine published by John August Media, LLC and hosted at TechnicaCuriosa.com for amateur astronomers . Prior to its revival in 2009, the title was published between 1893 and 1951. [ 1 ] It was the successor to The Sidereal Messenger , which was published from March 1882 to 1892. [ 1 ]... | https://en.wikipedia.org/wiki/Popular_Astronomy_(US_magazine) |
1800s: Martineau · Tocqueville · Marx · Spencer · Le Bon · Ward · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Mannheim · Elias
In sociology , popularity is how much a person, idea, place, item or other concept is either liked or accorded status [ 1 ] [ 2 ] [ 3 ] by other people. L... | https://en.wikipedia.org/wiki/Popularity |
The term population biology has been used with different meanings.
In 1971, Edward O. Wilson et al . used the term in the sense of applying mathematical models to population genetics , community ecology , and population dynamics . [ 1 ] Alan Hastings used the term in 1997 as the title of his book on the mathematics us... | https://en.wikipedia.org/wiki/Population_biology |
Population equivalent (PE) or unit per capita loading , or equivalent person (EP) , is a parameter for characterizing industrial wastewaters . It essentially compares the polluting potential of an industry (in terms of biodegradable organic matter) with a population (or certain number of people), which would produce th... | https://en.wikipedia.org/wiki/Population_equivalent |
Population genetics is a subfield of genetics that deals with genetic differences within and among populations , and is a part of evolutionary biology . Studies in this branch of biology examine such phenomena as adaptation , speciation , and population structure . [ 1 ]
Population genetics was a vital ingredient in t... | https://en.wikipedia.org/wiki/Population_genetics |
The population index , or r-value, indicates the magnitude distribution of a meteor shower . Values below 2.5 correspond to distributions where bright meteors are more frequent than average, while values above 3.0 mean that the share of faint meteors is larger than usual. [ 1 ] Population indices are not solely associa... | https://en.wikipedia.org/wiki/Population_index |
The field of population informatics is the systematic study of populations via secondary analysis of massive data collections (termed " big data ") about people. Scientists in the field refer to this massive data collection as the social genome , denoting the collective digital footprint of our society. Population in... | https://en.wikipedia.org/wiki/Population_informatics |
In physics , specifically statistical mechanics , a population inversion occurs when a system (such as a group of atoms or molecules ) exists in a state in which more members of the system are in higher, excited states than in lower, unexcited energy states . It is called an "inversion" because in many familiar and com... | https://en.wikipedia.org/wiki/Population_inversion |
In statistics a population proportion , generally denoted by P {\displaystyle P} or the Greek letter π {\displaystyle \pi } , [ 1 ] is a parameter that describes a percentage value associated with a population . A census can be conducted to determine the actual value of a population parameter, but often a census is not... | https://en.wikipedia.org/wiki/Population_proportion |
Population viability analysis ( PVA ) is a species -specific method of risk assessment frequently used in conservation biology .
It is traditionally defined as the process that determines the probability that a population will go extinct within a given number of years.
More recently, PVA has been described as a marriag... | https://en.wikipedia.org/wiki/Population_viability_analysis |
Pore-C is a genomic technique [ 1 ] [ 2 ] [ 3 ] which utilizes chromatin conformation capture (3C) and Oxford Nanopore Technologies ' (ONT) long-read sequencing to characterize three-dimensional (3D) chromatin structure. To characterize concatemers , the originators of Pore-C developed an algorithm to identify alignmen... | https://en.wikipedia.org/wiki/Pore-C |
Pore pressure gradient is a dimensional petrophysical term used by drilling engineers and mud engineers during the design of drilling programs for drilling (constructing) oil and gas wells into the earth. It is the pressure gradient inside the pore space of the rock column from the surface of the ground down to the tot... | https://en.wikipedia.org/wiki/Pore_pressure_gradient |
The pore space of soil contains the liquid and gas phases of soil , i.e., everything but the solid phase that contains mainly minerals of varying sizes as well as organic compounds .
In order to understand porosity better a series of equations have been used to express the quantitative interactions between the three p... | https://en.wikipedia.org/wiki/Pore_space_in_soil |
Pore structure is a common term employed to characterize the porosity , pore size, pore size distribution, and pore morphology (such as pore shape, surface roughness, and tortuosity of pore channels) of a porous medium . [ 1 ] [ 2 ] Pores are the openings in the surfaces impermeable porous matrix which gases, liquids, ... | https://en.wikipedia.org/wiki/Pore_structure |
Poribacteria are a candidate phylum of bacteria originally discovered [ 1 ] in the microbiome of marine sponges ( Porifera ). Poribacteria are Gram-negative primarily aerobic mixotrophs with the ability for oxidative phosphorylation , glycolysis , and autotrophic carbon fixation via the Wood – Ljungdahl pathway . [ 2 ]... | https://en.wikipedia.org/wiki/Poribacteria |
A porism is a mathematical proposition or corollary . It has been used to refer to a direct consequence of a proof , analogous to how a corollary refers to a direct consequence of a theorem . In modern usage, it is a relationship that holds for an infinite range of values but only if a certain condition is assumed, suc... | https://en.wikipedia.org/wiki/Porism |
Poroelasticity is a field in materials science and mechanics that studies the interaction between fluid flow, pressure and bulk solid deformation within a linear porous medium and it is an extension of elasticity and porous medium flow (diffusion equation). [ 1 ] The deformation of the medium influences the flow of the... | https://en.wikipedia.org/wiki/Poroelasticity |
Poromechanics is a branch of physics and specifically continuum mechanics that studies the behavior of fluid-saturated porous media . [ 1 ] A porous medium or a porous material is a solid (referred to as matrix) permeated by an interconnected network of pores or voids filled with a fluid . In general, the fluid may be ... | https://en.wikipedia.org/wiki/Poromechanics |
Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter , total pore volume , surface area , and bulk and absolute densities .
The technique involves the intrusion of a non-wetting liquid (often mercury ) at high pressure into a mate... | https://en.wikipedia.org/wiki/Porosimetry |
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material , and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from th... | https://en.wikipedia.org/wiki/Porosity |
Porous carbons (PCs) are versatile materials with a wide range of applications, including sensors, actuators , thermal insulation , and energy conversion and supercapacitors. [ 1 ] [ 2 ] Some examples of PCs are graphene and carbon nanotube -based aerogel . Physical properties that make PCs unique are their low density... | https://en.wikipedia.org/wiki/Porous_carbon |
Porous glass is glass that includes pores, usually in the nanometre - or micrometre -range, commonly prepared by one of the following processes: through metastable phase separation in borosilicate glasses (such as in their system SiO 2 -B 2 O 3 -Na 2 O), followed by liquid extraction of one of the formed phases; [ 1 ] ... | https://en.wikipedia.org/wiki/Porous_glass |
In materials science , a porous medium or a porous material is a material containing pores (voids). [ 1 ] The skeletal portion of the material is often called the "matrix" or "frame". The pores are typically filled with a fluid ( liquid or gas ). The skeletal material is usually a solid , but structures like foams are ... | https://en.wikipedia.org/wiki/Porous_medium |
The porous medium equation , also called the nonlinear heat equation , is a nonlinear partial differential equation taking the form: [ 1 ]
∂ u ∂ t = Δ ( u m ) , m > 1 {\displaystyle {\frac {\partial u}{\partial t}}=\Delta \left(u^{m}\right),\quad m>1}
where Δ {\displaystyle \Delta } is the Laplace operator . It may a... | https://en.wikipedia.org/wiki/Porous_medium_equation |
Porous polymers are a class of porous media materials in which monomers form 2D and 3D polymers containing angstrom- to nanometer-scale pores formed by the arrangement of the monomers. They may be either crystalline or amorphous. Subclasses include covalent organic frameworks (COFs), hydrogen-bonded organic frameworks ... | https://en.wikipedia.org/wiki/Porous_polymer |
Porphine or porphin is an organic compound of empirical formula C 20 H 14 N 4 . It is heterocyclic and aromatic . The molecule is a flat macrocycle , consisting of four pyrrole -like rings joined by four methine bridges, which makes it the simplest of the tetrapyrroles . [ 2 ]
The nonpolar tetrapyrrolic ring structure... | https://en.wikipedia.org/wiki/Porphine |
Porphobilinogen ( PBG ) is an organic compound that occurs in living organisms as an intermediate in the biosynthesis of porphyrins , which include critical substances like hemoglobin and chlorophyll . [ 1 ]
The structure of the molecule can be described as molecule of pyrrole with sidechains substituted for hydrogen ... | https://en.wikipedia.org/wiki/Porphobilinogen |
In philosophy (particularly the theory of categories ), the Porphyrian tree or Tree of Porphyry is a classic device for illustrating a "scale of being" ( Latin : scala praedicamentalis ), attributed to the 3rd-century CE Greek neoplatonist philosopher and logician Porphyry , and revived through the translations of Boet... | https://en.wikipedia.org/wiki/Porphyrian_tree |
Porphyrins ( / ˈ p ɔːr f ər ɪ n s / POR -fər-ins ) are a group of heterocyclic , macrocyclic , organic compounds , composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges ( =CH− ). In vertebrates , an essential member of the porphyrin group is heme , which is a component of... | https://en.wikipedia.org/wiki/Porphyrin |
Port-Royal Logic , or Logique de Port-Royal , is the common name of La logique, ou l'art de penser , an important textbook on logic first published anonymously in 1662 by Antoine Arnauld and Pierre Nicole , two prominent members of the Jansenist movement, centered on Port-Royal . Blaise Pascal likely contributed consid... | https://en.wikipedia.org/wiki/Port-Royal_Logic |
Port and starboard are nautical terms for watercraft and spacecraft , referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front).
Vessels with bilateral symmetry have left and right halves which are mirror images of each other. One asymmetric feature is where access to a b... | https://en.wikipedia.org/wiki/Port_and_starboard |
PortableApps.com is a website that distributes free applications for Windows that have been packaged for portability. These portable applications are intended to be used from removable storage devices such as USB flash drives .
The site was founded by John T. Haller and includes contributions from over 100 people, inc... | https://en.wikipedia.org/wiki/PortableApps.com |
The Portable Aqua Unit for Lifesaving (short PAUL ), also known as Water Backpack is a portable membrane water filter developed at the University of Kassel for humanitarian aid. It allows the decentralized supply of clean water in emergency and disaster situations.
The filter only needs water (e.g. from wells or rive... | https://en.wikipedia.org/wiki/Portable_Aqua_Unit_for_Lifesaving |
Portable Compiled Format (PCF) is a bitmap font format used by X Window System in its core font system, and has been used for decades. PCF fonts are usually installed, by default, on most Unix -based operating systems, and are used in terminals such as xterm . PCF fonts replaced Bitmap Distribution Format due to a slig... | https://en.wikipedia.org/wiki/Portable_Compiled_Format |
In electrical safety testing , portable appliance testing ( PAT inspection or PAT testing ) is a process by which electrical appliances are routinely checked for safety, commonly used in the United Kingdom , Ireland , New Zealand and Australia . In Australia and New Zealand it is commonly known as Test and Tag . The fo... | https://en.wikipedia.org/wiki/Portable_appliance_testing |
A portable collision avoidance system ( PCAS ) is a proprietary aircraft collision avoidance system similar in function to traffic collision avoidance system (TCAS). TCAS is the industry standard for commercial collision avoidance systems but PCAS is gaining recognition as an effective means of collision avoidance for ... | https://en.wikipedia.org/wiki/Portable_collision_avoidance_system |
A portable emissions measurement system ( PEMS ) is a vehicle emissions testing device that is small and light enough to be carried inside or moved with a motor vehicle that is being driven during testing, rather than on the stationary rollers of a dynamometer that only simulates real-world driving.
Early examples of ... | https://en.wikipedia.org/wiki/Portable_emissions_measurement_system |
Portable water purification devices are self-contained, easily transported units used to purify water from untreated sources (such as rivers, lakes, and wells ) for drinking purposes. Their main function is to eliminate pathogens , and often also suspended solids and some unpalatable or toxic compounds .
These units p... | https://en.wikipedia.org/wiki/Portable_water_purification |
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Algae ( UK : / ˈ æ l ɡ iː / AL -ghee , US : / ˈ æ l dʒ iː / ⓘ AL -jee ; sg. : alga / ˈ æ l ɡ ə / ⓘ AL -gə ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants , and includes species from multiple distinct clades . Such or... | https://en.wikipedia.org/wiki/Portal:Algae |
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Animals are multicellular , eukaryotic organisms in the biological kingdom Animalia ( / ˌ æ n ɪ ˈ m eɪ l i ə / ). With few exceptions, animals consume organic material , breathe oxygen , have myocytes and are able to move , can reproduce sexually , and grow from a hollow sphere of cel... | https://en.wikipedia.org/wiki/Portal:Animals |
Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning , designing , and constructing buildings or other structures . The term comes from Latin architectura ; from Ancient G... | https://en.wikipedia.org/wiki/Portal:Architecture |
Arithmetic is an elementary branch of mathematics that deals with numerical operations like addition , subtraction , multiplication , and division . In a wider sense, it also includes exponentiation , extraction of roots , and taking logarithms . ( Full article... )
The Egyptians and Babylonians used all the elementar... | https://en.wikipedia.org/wiki/Portal:Arithmetic |
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