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In number theory , Hurwitz's theorem , named after Adolf Hurwitz , gives a bound on a Diophantine approximation . The theorem states that for every irrational number ξ there are infinitely many relatively prime integers m , n such that | ξ − m n | < 1 5 n 2 . {\displaystyle \left|\xi -{\frac {m}{n}}\right|<{\frac {1}{{... | https://en.wikipedia.org/wiki/Hurwitz's_theorem_(number_theory) |
In mathematics, the Hurwitz class number H ( N ), introduced by Adolf Hurwitz , is a modification of the class number of positive definite binary quadratic forms of discriminant – N , where forms are weighted by 2/ g for g the order of their automorphism group, and where H (0) = –1/12 .
Zagier (1975) showed that the ... | https://en.wikipedia.org/wiki/Hurwitz_class_number |
In mathematics, Hurwitz determinants were introduced by Adolf Hurwitz ( 1895 ), who used them to give a criterion for all roots of a polynomial to have negative real part.
Consider a characteristic polynomial P in the variable λ of the form:
where a i {\displaystyle a_{i}} , i = 0 , 1 , … , n {\displaystyle i=0,1,\ld... | https://en.wikipedia.org/wiki/Hurwitz_determinant |
In mathematics , a Hurwitz polynomial (named after German mathematician Adolf Hurwitz ) is a polynomial whose roots (zeros) are located in the left half-plane of the complex plane or on the imaginary axis , that is, the real part of every root is zero or negative. [ 1 ] Such a polynomial must have coefficients that are... | https://en.wikipedia.org/wiki/Hurwitz_polynomial |
In mathematics, the Hurwitz problem (named after Adolf Hurwitz ) is the problem of finding multiplicative relations between quadratic forms which generalise those known to exist between sums of squares in certain numbers of variables.
There are well-known multiplicative relationships between sums of squares in two var... | https://en.wikipedia.org/wiki/Hurwitz_problem |
In ecological theory, the Hutchinson's ratio is the ratio of the size differences between similar species when they are living together as compared to when they are isolated. It is named after G. Evelyn Hutchinson who concluded that various key attributes in species varied according to the ratio of 1:1.1 to 1:1.4. [ 1 ... | https://en.wikipedia.org/wiki/Hutchinson's_ratio |
In ecological theory, the Hutchinson's ratio is the ratio of the size differences between similar species when they are living together as compared to when they are isolated. It is named after G. Evelyn Hutchinson who concluded that various key attributes in species varied according to the ratio of 1:1.1 to 1:1.4. The ... | https://en.wikipedia.org/wiki/Hutchinson's_rule |
In mathematics , the Hutchinson metric otherwise known as Kantorovich metric is a function which measures "the discrepancy between two images for use in fractal image processing " and "can also be applied to describe the similarity between DNA sequences expressed as real or complex genomic signals". [ 1 ] [ 2 ]
Consid... | https://en.wikipedia.org/wiki/Hutchinson_metric |
Hutchison Asia Telecom Group or HAT , is a division of Hong Kong-based multinational conglomerate CK Hutchison Holdings . [ 1 ] The division provides telecommunications services to several Asian countries. The division was formerly incorporated as Hutchison Telecommunications International Limited , known as Hutchison ... | https://en.wikipedia.org/wiki/Hutchison_Asia_Telecom |
The Hutter Prize is a cash prize funded by Marcus Hutter which rewards data compression improvements on a specific 1 GB English text file, with the goal of encouraging research in artificial intelligence (AI).
Launched in 2006, the prize awards 5000 euros for each one percent improvement (with 500,000 euros total fund... | https://en.wikipedia.org/wiki/Hutter_Prize |
The Huwood Power Loader was mechanical device of roughly 6 ft by 2 ft by 1 ft dimensions and powered by a 10 hp engine, used to move cut coal from the coal face on to the conveyor. The machine was equipped with winches which used haulage ropes to drag the machine along the coal face and used both horizontal and rotary... | https://en.wikipedia.org/wiki/Huwood_power_loader |
The Huzita–Justin axioms or Huzita–Hatori axioms are a set of rules related to the mathematical principles of origami , describing the operations that can be made when folding a piece of paper. The axioms assume that the operations are completed on a plane (i.e. a perfect piece of paper), and that all folds are linear.... | https://en.wikipedia.org/wiki/Huzita–Hatori_axioms |
Chemical
Neurological
The Hwang affair , [ 1 ] or Hwang scandal , [ 2 ] or Hwanggate , [ 3 ] is a case of scientific misconduct and ethical issues surrounding a South Korean biologist, Hwang Woo-suk , who claimed to have created the first human embryonic stem cells by cloning in 2004. [ 4 ] [ 5 ] Hwang and his resear... | https://en.wikipedia.org/wiki/Hwang_affair |
HWiNFO (also known as HWiNFO64 [ 1 ] ) is a system monitoring , system profiling and system diagnostics program for Windows and DOS -based systems. [ 2 ] It is developed by Martin Malik and REALiX.
It was used by NASA during several tests of different microprocessors, including an AMD Ryzen 3 1200 and Intel i5-6600K .... | https://en.wikipedia.org/wiki/Hwinfo |
Hy's law is a rule of thumb that a patient is at high risk of a fatal drug-induced liver injury if given a medication that causes hepatocellular injury (not Hepatobiliary injury ) with jaundice . [ 1 ] The law is based on observations by Hy Zimmerman, a major scholar of drug-induced liver injury. [ 2 ] [ 3 ] [ 4 ] Some... | https://en.wikipedia.org/wiki/Hy's_law |
HyShot is a research project of The University of Queensland , Australia Centre for Hypersonics , to demonstrate the possibility of supersonic combustion under flight conditions using two scramjet engines, one designed by The University of Queensland and one designed by QinetiQ (formerly the MOD's Defence Evaluation & ... | https://en.wikipedia.org/wiki/HyShot |
Hybricon Corporation is a provider of systems packaging serving the military , aerospace , homeland security , medical and high-end Industrial markets and develops embedded computing systems using OpenVPX , VPX , VXS , VMEbus , VME64X, CompactPCI , rugged MicroTCA, and custom bus structures.
Charles Michael Hayward, w... | https://en.wikipedia.org/wiki/Hybricon_Corporation |
CORDIC ( coordinate rotation digital computer ), Volder's algorithm , Digit-by-digit method , Circular CORDIC ( Jack E. Volder ), [ 1 ] [ 2 ] Linear CORDIC , Hyperbolic CORDIC (John Stephen Walther), [ 3 ] [ 4 ] and Generalized Hyperbolic CORDIC ( GH CORDIC ) (Yuanyong Luo et al.), [ 5 ] [ 6 ] is a simple and efficient... | https://en.wikipedia.org/wiki/Hybrid_CORDIC |
Hybrid Insect Micro-Electro-Mechanical Systems (HI-MEMS) is a project of DARPA , a unit of the United States Department of Defense. Created in 2006, the unit's goal is the creation of tightly coupled machine - insect interfaces by placing micro-mechanical systems inside the insects during the early stages of metamorp... | https://en.wikipedia.org/wiki/Hybrid_Insect_Micro-Electro-Mechanical_Systems |
Hybrid automatic repeat request ( hybrid ARQ or HARQ ) is a combination of high-rate forward error correction (FEC) and automatic repeat request (ARQ) error-control. In standard ARQ, redundant bits are added to data to be transmitted using an error-detecting (ED) code such as a cyclic redundancy check (CRC). Receivers ... | https://en.wikipedia.org/wiki/Hybrid_automatic_repeat_request |
In automata theory , a hybrid automaton (plural: hybrid automata or hybrid automatons ) is a mathematical model for precisely describing hybrid systems , for instance systems in which digital computational processes interact with analog physical processes. A hybrid automaton is a finite-state machine with a finite set ... | https://en.wikipedia.org/wiki/Hybrid_automaton |
In telecommunications , a hybrid balance is an expression of the degree of electrical symmetry between two impedances connected to two conjugate sides of a hybrid coil or resistance hybrid . It is usually expressed in dB .
If the respective impedances of the branches of the hybrid that are connected to the conjugate s... | https://en.wikipedia.org/wiki/Hybrid_balance |
A hybrid bond graph is a graphical description of a physical dynamic system with discontinuities (i.e., a hybrid dynamical system ). Similar to
a regular bond graph , it is an energy-based technique. However, it allows instantaneous switching of the junction structure, which may violate the principle of continuity of ... | https://en.wikipedia.org/wiki/Hybrid_bond_graph |
Hybrid computers are computers that exhibit features of analog computers and digital computers . The digital component normally serves as the controller and provides logical and numerical operations, while the analog component often serves as a solver of differential equations and other mathematically complex problems.... | https://en.wikipedia.org/wiki/Hybrid_computer |
The hybrid difference scheme [ 1 ] [ 2 ] is a method used in the numerical solution for convection–diffusion problems. It was introduced by Spalding (1970). It is a combination of central difference scheme and upwind difference scheme as it exploits the favorable properties of both of these schemes. [ 3 ] [ 4 ]
Source... | https://en.wikipedia.org/wiki/Hybrid_difference_scheme |
In bioinformatics , hybrid genome assembly refers to utilizing various sequencing technologies to achieve the task of assembling a genome from fragmented, sequenced DNA resulting from shotgun sequencing. Genome assembly presents one of the most challenging tasks in genome sequencing as most modern DNA sequencing techno... | https://en.wikipedia.org/wiki/Hybrid_genome_assembly |
Hybrid growth disorders refer to reduced growth or overgrowth in an organism that is a hybrid of two different species. [ 1 ] In some sense, it is a type of hybrid dysgenesis when the growth disorder proves deleterious, making it the opposite of heterosis or hybrid vigour . [ 2 ] [ 3 ]
Hybrid growth disorders may be r... | https://en.wikipedia.org/wiki/Hybrid_growth_disorders |
The hybrid iguana is a first-generation hybrid , the result of intergeneric breeding between a male marine iguana ( Amblyrhynchus cristatus ) and a female Galapagos land iguana ( Conolophus subcristatus ) on South Plaza Island in the Galápagos Islands , where the territories of the two species overlap.
Hybrid iguanas... | https://en.wikipedia.org/wiki/Hybrid_iguana |
Hybrid incompatibility is a phenomenon in plants and animals, wherein offspring produced by the mating of two different species or populations have reduced viability and/or are less able to reproduce. Examples of hybrids include mules and ligers from the animal world, and subspecies of the Asian rice crop Oryza sativa ... | https://en.wikipedia.org/wiki/Hybrid_incompatibility |
Hybrid inviability is a post-zygotic barrier , which reduces a hybrid 's capacity to mature into a healthy, fit adult. [ 1 ] The relatively low health of these hybrids relative to pure-breed individuals prevents gene flow between species. Thus, hybrid inviability acts as an isolating mechanism , limiting hybridization... | https://en.wikipedia.org/wiki/Hybrid_inviability |
Hybrid masonry is a new type of building system that uses engineered, reinforced masonry to brace frame structures. Typically, hybrid masonry is implemented with concrete masonry panels used to brace steel frame structures. The basic concept is to attach a reinforced concrete masonry panel to a structural steel frame s... | https://en.wikipedia.org/wiki/Hybrid_masonry |
Hybrid navigation is the simultaneous use of more than one navigation system for location data determination, needed for navigation . By using multiple systems at once, the accuracy as a whole is improved. It also allows for a more reliable navigation system, as if one system fails, the other can kick in and provide ac... | https://en.wikipedia.org/wiki/Hybrid_navigation |
Hybrid physical–chemical vapor deposition (HPCVD) is a thin-film deposition technique, that combines physical vapor deposition (PVD) with chemical vapor deposition (CVD).
For the instance of magnesium diboride (MgB 2 ) thin-film growth, HPCVD process uses diborane (B 2 H 6 ) as the boron precursor gas, but unlike conv... | https://en.wikipedia.org/wiki/Hybrid_physical–chemical_vapor_deposition |
Hybrid rail , also known as diesel light rail transit ( DLRT ), is a mode of passenger rail service unique to North America that uses lightweight multiple unit trains —typically diesel multiple units (DMUs)—operating on the national rail system . In the United States , these vehicles do not comply with Federal Railroad... | https://en.wikipedia.org/wiki/Hybrid_rail |
Hybrid speciation is a form of speciation where hybridization between two different species leads to a new species, reproductively isolated from the parent species. Previously, reproductive isolation between two species and their parents was thought to be particularly difficult to achieve, and thus hybrid species were ... | https://en.wikipedia.org/wiki/Hybrid_speciation |
The hybrid sulfur cycle (HyS) is a two-step water-splitting process intended to be used for hydrogen production . Based on sulfur oxidation and reduction , it is classified as a hybrid thermochemical cycle because it uses an electrochemical (instead of a thermochemical) reaction for one of the two steps. The remaining... | https://en.wikipedia.org/wiki/Hybrid_sulfur_cycle |
A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids .
Hybrid powertrains are designed to switch from one power source to another to maximize both ... | https://en.wikipedia.org/wiki/Hybrid_vehicle |
Hybrid vehicle drivetrains transmit power to the driving wheels for hybrid vehicles . A hybrid vehicle has multiple forms of motive power, and can come in many configurations. For example, a hybrid may receive its energy by burning gasoline, but switch between an electric motor and a combustion engine .
A typical powe... | https://en.wikipedia.org/wiki/Hybrid_vehicle_drivetrain |
A hybridization assay comprises any form of quantifiable hybridization i.e. the quantitative annealing of two complementary strands of nucleic acids , known as nucleic acid hybridization . [ 1 ]
In the context of biochemistry and drug development, a hybridization assay is a type of Ligand Binding Assay (LBA) used to ... | https://en.wikipedia.org/wiki/Hybridization_assay |
In molecular biology , a hybridization probe ( HP ) is a fragment of DNA or RNA , usually 15–10000 nucleotides long, which can be radioactively or fluorescently labeled . HPs can be used to detect the presence of nucleotide sequences in analyzed RNA or DNA that are complementary to the sequence in the probe. [ 1 ] The ... | https://en.wikipedia.org/wiki/Hybridization_probe |
Hybridoma technology is a method for producing large quantities of monoclonal antibodies by fusing antibody producing B cells with myeloma cells (cancerous B cells). This creates hybrid cells, hybridomas, that produce the antibody from their parent B cell whilst maintaining the properties of the parental myeloma cell l... | https://en.wikipedia.org/wiki/Hybridoma_technology |
Hybrizyme is a term coined to indicate novel or normally rare gene variants (or alleles ) that are associated with hybrid zones , geographic areas where two related taxa (e.g. species or subspecies ) meet, mate, and produce hybrid offspring. [ 1 ] The hybrizyme phenomenon is widespread and these alleles occur commonly,... | https://en.wikipedia.org/wiki/Hybrizyme |
A hyclate ( Latin : hyclas ) is a pharmaceutical term for hydrochloride hemiethanolate hemihydrate [ 1 ] [ 2 ] (· HCl · 1 / 2 EtOH · 1 / 2 H 2 O ), e.g. doxycycline hyclate. [ 3 ] [ 4 ]
This article about a salt (chemistry) is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Hyclate |
In mathematics, specifically in graph theory and number theory , a hydra game is a single-player iterative mathematical game played on a mathematical tree called a hydra where, usually, the goal is to cut off the hydra's "heads" while the hydra simultaneously expands itself. Hydra games can be used to generate large nu... | https://en.wikipedia.org/wiki/Hydra_game |
A hydrant is an outlet from a fluid main often consisting of an upright pipe with a valve attached, from which fluid (e.g. water or fuel ) can be tapped.
Depending on the fluid involved, the term may refer to: | https://en.wikipedia.org/wiki/Hydrant |
Hydrastine is an isoquinoline alkaloid which was discovered in 1851 by Alfred P. Durand . [ 1 ] Nitric acid induced hydrolysis of hydrastine yields hydrastinine , which was patented by Bayer as a haemostatic drug in the early 1900's. [ 2 ] It is present in Hydrastis canadensis (thus the name) and other plants of the fa... | https://en.wikipedia.org/wiki/Hydrastine |
In chemistry , a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understood.
Hydrates are not inorganic salts "containing water molecules combin... | https://en.wikipedia.org/wiki/Hydrate |
In chemistry , hydration energy (also hydration enthalpy ) is the amount of energy released when one mole of ions undergoes solvation . Hydration energy is one component in the quantitative analysis of solvation . It is a particular special case of water . [ 1 ] The value of hydration energies is one of the most chall... | https://en.wikipedia.org/wiki/Hydration_energy |
In coordination chemistry , hydration isomerism is a kind of isomerism that is observed in some solids. Hydration isomers have identical formula but differ with respect to the numbers of water ligands .
One example is the pair [CrCl(H 2 O) 5 ]Cl 2 •H 2 O and [Cr(H 2 O) 6 ]Cl 3 . [ 1 ] The former has one water of crys... | https://en.wikipedia.org/wiki/Hydration_isomerism |
The hydration number of a compound is defined as the number of molecules of water bonded to a central ion, often a metal cation. The hydration number is related to the broader concept of solvation number , the number of solvent molecules bonded to a central atom. The hydration number varies with the atom or ion of in... | https://en.wikipedia.org/wiki/Hydration_number |
In chemistry , a hydration reaction is a chemical reaction in which a substance combines with water . In organic chemistry , water is added to an unsaturated substrate, which is usually an alkene or an alkyne . This type of reaction is employed industrially to produce ethanol , isopropanol , and butan-2-ol . [ 1 ]
Any... | https://en.wikipedia.org/wiki/Hydration_reaction |
Hydraulic Launch Assist ( HLA ) is the name of a hydraulic hybrid regenerative braking system for land vehicles produced by the Eaton Corporation . [ 1 ]
The HLA system recycles energy by converting kinetic energy into potential energy during deceleration via hydraulics , storing the energy at high pressure in an accu... | https://en.wikipedia.org/wiki/Hydraulic_Launch_Assist |
A hydraulic accumulator is a pressure storage reservoir in which an incompressible hydraulic fluid is held under pressure that is applied by an external source of mechanical energy . The external source can be an engine, a spring , a raised weight , or a compressed gas . [ note 1 ] An accumulator enables a hydraulic sy... | https://en.wikipedia.org/wiki/Hydraulic_accumulator |
Hydraulic action , most generally, is the ability of moving water (flowing or waves) to dislodge and transport rock particles. This includes a number of specific erosional processes, including abrasion , at facilitated erosion, such as static erosion where water leaches salts and floats off organic material from uncons... | https://en.wikipedia.org/wiki/Hydraulic_action |
Water transportation and distribution networks require hydraulic calculations to determination the flowrate and pressure characteristics at one or several consumption points and the water supply flowrate and pressures needed to meet the design requirements. [ 1 ]
In the context of fire safety , hydraulic calculations ... | https://en.wikipedia.org/wiki/Hydraulic_calculation |
A chainsaw (or chain saw [ 1 ] ) is a portable handheld power saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar.
Modern chainsaws are typically gasoline or electric and are used in activities such as tree felling , limbing , bucking , pruning , cutting firebreaks in wildland fire ... | https://en.wikipedia.org/wiki/Hydraulic_chainsaw |
Hydraulic clearance. Flow in narrow clearances are of vital importance in hydraulic system component design. The flow in a narrow circular clearance of a spool valve can be calculated according to the formula below if the height is negligible compared to the width of the clearance, such as most of the clearances in hyd... | https://en.wikipedia.org/wiki/Hydraulic_clearance |
In science and engineering , hydraulic conductivity ( K , in SI units of meters per second), is a property of porous materials , soils and rocks , that describes the ease with which a fluid (usually water) can move through the pore space , or fracture network. [ 1 ] It depends on the intrinsic permeability ( k , unit: ... | https://en.wikipedia.org/wiki/Hydraulic_conductivity |
A hydraulic cylinder (also called a linear hydraulic motor ) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. [ citation needed ] It has many applications, notably in construction equipment ( engineering vehicles ), manufacturing machinery , elevators , and civil eng... | https://en.wikipedia.org/wiki/Hydraulic_cylinder |
The hydraulic diameter , D H , is a commonly used term when handling flow in non-circular tubes and channels. Using this term, one can calculate many things in the same way as for a round tube. When the cross-section is uniform along the tube or channel length, it is defined as [ 1 ] [ 2 ]
where
More intuitively, the... | https://en.wikipedia.org/wiki/Hydraulic_diameter |
Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and becomes pressurized according to the resistance present. The fluid is controlled ... | https://en.wikipedia.org/wiki/Hydraulic_drive_system |
A hydraulic drop is a type of local phenomena found in open channel flow . It is a rapid change in the depth of flow from a high stage to a low stage that results in a steep depression in the water surface. It is often caused by an abrupt change in the channel slope.
Another type of local phenomena found in an open ch... | https://en.wikipedia.org/wiki/Hydraulic_drop |
Hydraulic engineering as a sub-discipline of civil engineering is concerned with the flow and conveyance of fluids , principally water and sewage. One feature of these systems is the extensive use of gravity as the motive force to cause the movement of the fluids. This area of civil engineering is intimately related to... | https://en.wikipedia.org/wiki/Hydraulic_engineering |
A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery . Common hydraulic fluids are based on mineral oil or water. [ 1 ] Examples of equipment that might use hydraulic fluids are excavators and backhoes , hydraulic brakes , power steering systems, automatic transmissio... | https://en.wikipedia.org/wiki/Hydraulic_fluid |
Hydraulic head or piezometric head is a measurement related to liquid pressure (normalized by specific weight ) and the liquid elevation above a vertical datum . [ 1 ] [ 2 ] It is usually measured as an equivalent liquid surface elevation, expressed in units of length, at the entrance (or bottom) of a piezometer . In a... | https://en.wikipedia.org/wiki/Hydraulic_head |
A hydraulic jump is a phenomenon in the science of hydraulics which is frequently observed in open channel flow such as rivers and spillways . When liquid at high velocity discharges into a zone of lower velocity, a rather abrupt rise occurs in the liquid surface. The rapidly flowing liquid is abruptly slowed and incre... | https://en.wikipedia.org/wiki/Hydraulic_jump |
Hydraulic jump in a rectangular channel , also known as classical jump , is a natural phenomenon that occurs whenever flow changes from supercritical to subcritical flow. In this transition, the water surface rises abruptly, surface rollers are formed, intense mixing occurs, air is entrained, and often a large amount o... | https://en.wikipedia.org/wiki/Hydraulic_jumps_in_rectangular_channels |
Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and becomes pressurized according to the resistance present. The fluid is controlled ... | https://en.wikipedia.org/wiki/Hydraulic_machinery |
A hydraulic manifold is a component that regulates fluid flow between pumps and actuators and other components in a hydraulic system. It is like a switchboard in an electrical circuit because it lets the operator control how much fluid flows between which components of a hydraulic machinery. For example, in a backhoe l... | https://en.wikipedia.org/wiki/Hydraulic_manifold |
A hydraulic modular trailer (HMT) is a special platform trailer unit which feature swing axles , hydraulic suspension , independently steerable axles , two or more axle rows, compatible to join two or more units longitudinally and laterally and uses power pack unit (PPU) to steer and adjust height. [ 1 ] These trailer ... | https://en.wikipedia.org/wiki/Hydraulic_modular_trailer |
A hydraulic power network is a system of interconnected pipes carrying pressurized liquid used to transmit mechanical power from a power source, like a pump , to hydraulic equipment like lifts or motors . The system is analogous to an electrical grid transmitting power from a generating station to end-users. Only a few... | https://en.wikipedia.org/wiki/Hydraulic_power_network |
A hydraulic pump is a mechanical source of power that converts mechanical power into hydraulic energy ( hydrostatic energy i.e. flow, pressure). Hydraulic pumps are used in hydraulic drive systems and can be hydrostatic or hydrodynamic. They generate flow with enough power to overcome pressure induced by a load at the ... | https://en.wikipedia.org/wiki/Hydraulic_pump |
Hydraulic redistribution is a passive mechanism where water is transported from moist to dry soils via subterranean networks. [ 1 ] It occurs in vascular plants that commonly have roots in both wet and dry soils, especially plants with both taproots that grow vertically down to the water table , and lateral roots that ... | https://en.wikipedia.org/wiki/Hydraulic_redistribution |
Hydraulic roughness is the measure of the amount of frictional resistance water experiences when passing over land and channel features. [ 1 ] It quantifies the impact of surface irregularities and obstructions on the flow of water.
One roughness coefficient is Manning's n-value . [ 2 ] Manning's n is used extensively ... | https://en.wikipedia.org/wiki/Hydraulic_roughness |
A hydraulic seal is a relatively soft, non-metallic ring , captured in a groove or fixed in a combination of rings, forming a seal assembly, to block or separate fluid in reciprocating motion applications. Hydraulic seals are vital in machinery . Their use is critical in providing a way for fluid power to be converted... | https://en.wikipedia.org/wiki/Hydraulic_seal |
Hydraulic shock ( colloquial : water hammer ; fluid hammer ) is a pressure surge or wave caused when a fluid in motion is forced to stop or change direction suddenly: a momentum change. It is usually observed in a liquid but gases can also be affected. This phenomenon commonly occurs when a valve closes suddenly at an ... | https://en.wikipedia.org/wiki/Hydraulic_shock |
Hydraulic tomography (HT) is a sequential cross-hole hydraulic test followed by inversion of all the data to map the spatial distribution of aquifer hydraulic properties. Specifically, HT involves installation of multiple wells in an aquifer, which are partitioned into several intervals along the depth using packers. A... | https://en.wikipedia.org/wiki/Hydraulic_tomography |
Hydraulics (from Ancient Greek ὕδωρ ( húdōr ) ' water ' and αὐλός ( aulós ) ' pipe ' ) [ 2 ] is a technology and applied science using engineering , chemistry , and other sciences involving the mechanical properties and use of liquids . At a very basic level, hydraulics is the liquid counterpart of pneumatics , which c... | https://en.wikipedia.org/wiki/Hydraulics |
Hydrazides in organic chemistry are a class of organic compounds with the formula R−NR 1 −NR 2 R 3 where R is acyl ( R'−C(=O)− ), sulfonyl ( R'−S(=O) 2 − ), phosphoryl ( (R'−) 2 P(=O)− ), phosphonyl ( (R'−O−) 2 P(=O)− ) and similar groups ( chalcogen analogs are included, for example sulfur analogs called thiohydrazide... | https://en.wikipedia.org/wiki/Hydrazide |
Hydrazine is an inorganic compound with the chemical formula N 2 H 4 . It is a simple pnictogen hydride , and is a colourless flammable liquid with an ammonia -like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate ( N 2 H 4 · x H 2 O ).
Hydrazine is mainly used as a fo... | https://en.wikipedia.org/wiki/Hydrazine |
Hydrazine nitrate is an inorganic compound with the chemical formula N 2 H 4 ·HN O 3 . It has usage in liquid explosives as an oxidizer . It exists in two crystalline forms, stable α-type and unstable β-type. The former is usually used in explosives. Its solubility is small in alcohols but
large in water and hydrazine ... | https://en.wikipedia.org/wiki/Hydrazine_nitrate |
Unsymmetrical dimethylhydrazine
Phenylhydrazine
2,4-Dinitrophenylhydrazine
1,2-Diphenylhydrazine
Tetraphenylhydrazine
Hydrazines (R 2 N−NR 2 ) are a class of chemical compounds with two nitrogen atoms linked via a covalent bond and which carry from one up to four alkyl or aryl substituents. Hydrazines can be consi... | https://en.wikipedia.org/wiki/Hydrazines |
Hydrazoic acid , also known as hydrogen azide , azic acid or azoimide , [ 2 ] is a compound with the chemical formula HN 3 . [ 3 ] It is a colorless, volatile, and explosive liquid at room temperature and pressure. It is a compound of nitrogen and hydrogen , and is therefore a pnictogen hydride . It was first isolated ... | https://en.wikipedia.org/wiki/Hydrazoic_acid |
Hydrazones are a class of organic compounds with the structure R 1 R 2 C=N−NH 2 . [ 1 ] They are related to ketones and aldehydes by the replacement of the oxygen =O with the = N−NH 2 functional group . They are formed usually by the action of hydrazine on ketones or aldehydes. [ 2 ] [ 3 ]
Hydrazine, organohydrazines,... | https://en.wikipedia.org/wiki/Hydrazone |
Hydric soil is soil which is permanently or seasonally saturated by water, resulting in anaerobic conditions, as found in wetlands .
Most soils are aerobic . This is important because plant roots respire (that is, they consume oxygen and carbohydrates while releasing carbon dioxide ) and there must be sufficient air—... | https://en.wikipedia.org/wiki/Hydric_soil |
In chemistry , a hydride is formally the anion of hydrogen (H − ), a hydrogen ion with two electrons. [ 1 ] In modern usage, this is typically only used for ionic bonds, but it is sometimes (and has been more frequently in the past) applied to all compounds containing covalently bound H atoms . In this broad and potent... | https://en.wikipedia.org/wiki/Hydride |
Hydride vapour-phase epitaxy ( HVPE ) is an epitaxial growth technique often employed to produce semiconductors such as GaN, GaAs, InP and their related compounds, in which hydrogen chloride is reacted at elevated temperature with the group-III metals to produce gaseous metal chlorides, which then react with ammonia to... | https://en.wikipedia.org/wiki/Hydride_vapour-phase_epitaxy |
Hydrindantin is an organic chemical thought to be involved with the ninhydrin test for amines . [ 2 ]
This article about a ketone is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Hydrindantin |
Hydrion is a trademarked name for a popular line of compound pH indicators , marketed by Micro Essential Laboratory Inc., exhibiting a series of color changes (typically producing a recognizably different color for each pH unit) over a range of pH values. Although solutions are available, the most common forms of Hydri... | https://en.wikipedia.org/wiki/Hydrion_paper |
HydroCAD is a computer-aided design (CAD) program used by civil engineers for modeling the hydrology and hydraulics (H&H) of stormwater runoff . [ 1 ] Its use as a tool has grown in the U.S. as rules for managing stormwater have become more stringent. Specifically, the National Pollutant Discharge Elimination System (N... | https://en.wikipedia.org/wiki/HydroCAD |
Hydroacylation is a type of organic reaction in which an electron-rich [ 1 ] unsaturated hydrocarbon inserts into a formyl C-H bond. With alkenes, the product is a ketone :
With an alkyne instead, the reaction produces an α,β-unsaturated ketone . [ 2 ]
The reaction requires a metal catalyst or a radical initiator . ... | https://en.wikipedia.org/wiki/Hydroacylation |
Hydroalkoxylation is a chemical reaction that combines alcohols with alkenes or alkynes . The process affords ethers .
The reaction converts alkenes to dialkyl or aryl-alkyl ethers:
Similarly, alkynes are converted to vinyl ethers:
As shown, the reaction follows the Markovnikov rule . The process exhibits good atom-... | https://en.wikipedia.org/wiki/Hydroalkoxylation |
In organic chemistry , hydroamination is the addition of an N−H bond of an amine across a carbon-carbon multiple bond of an alkene , alkyne , diene , or allene . [ 1 ] In the ideal case, hydroamination is atom economical and green . [ 2 ] Amines are common in fine-chemical, pharmaceutical, and agricultural industries. ... | https://en.wikipedia.org/wiki/Hydroamination |
Hydrobiology is the science of life and life processes in water. Much of modern hydrobiology can be viewed as a sub-discipline of ecology but the sphere of hydrobiology includes taxonomy , economic and industrial biology, morphology , and physiology. The one distinguishing aspect is that all fields relate to aquatic or... | https://en.wikipedia.org/wiki/Hydrobiology |
In organic chemistry , hydroboration refers to the addition of a hydrogen - boron bond to certain double and triple bonds involving carbon ( C=C , C=N , C=O , and C≡C ). This chemical reaction is useful in the organic synthesis of organic compounds . [ 1 ]
Hydroboration produces organoborane compounds that react with ... | https://en.wikipedia.org/wiki/Hydroboration |
In chemistry, a hydrobromide is an acid salt resulting, or regarded as resulting, from the reaction of hydrobromic acid with an organic base (e.g. an amine ). The compounds are similar to hydrochlorides .
Some drugs are formulated as hydrobromides, e.g. dextromethorphan hydrobromide.
This article about a salt (chemis... | https://en.wikipedia.org/wiki/Hydrobromide |
Hydrocarbon mixtures are a group of various volatile , highly flammable , mixtures used chiefly as nonpolar solvents .
Hydrocarbon mixtures are composed of petroleum ethers and other hydrocarbons . [ 1 ] Petroleum ether should not be confused with the class of organic compounds called ethers ; and equally, going unde... | https://en.wikipedia.org/wiki/Hydrocarbon_mixtures |
Hydrocarbon plants are plants that follow certain metabolic pathways that produce hydrocarbon products similar to petroleum. These
hydrocarbon products are called terpenoids . [ 1 ] The plants that produce terpenoids in large enough quantities
to be harvested can be as big as trees or as small as single-cell algae. The... | https://en.wikipedia.org/wiki/Hydrocarbon_plant |
Hydrocarbon poisoning is either the swallowing or breathing in of hydrocarbons . [ 1 ] Swallowing hydrocarbons may result in symptoms include coughing or vomiting. [ 1 ] Breathing in hydrocarbons may result in low blood oxygen and shortness of breath . [ 1 ] Complications may include confusion or seizures . [ 1 ]
Hydr... | https://en.wikipedia.org/wiki/Hydrocarbon_poisoning |
Hydrocarbonoclastic bacteria (also known as hydrocarbon degrading bacteria , oil degrading bacteria or HCB ) are a heterogeneous group of prokaryotes which can degrade and utilize hydrocarbon compounds as source of carbon and energy. Despite being present in most of environments around the world, several of these speci... | https://en.wikipedia.org/wiki/Hydrocarbonoclastic_bacteria |
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