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Stings usually cause severe pain to humans, lasting one to three hours. Red, whip-like welts appear on the skin that last two or three days after the sting. In some cases, the venom may travel to the lymph nodes and may cause symptoms that mimic an allergic reaction, including swelling of the larynx, airway blockage, c... | Portuguese man o' war | Wikipedia | 357 | 152952 | https://en.wikipedia.org/wiki/Portuguese%20man%20o%27%20war | Biology and health sciences | Cnidarians | Animals |
Habitat
P. physalis is a member of the neuston (the floating community of organisms that live at the interface between water and air). This community is exposed to a unique set of environmental conditions including prolonged exposure to intense ultraviolet light, risk of desiccation, and rough sea conditions. The gas-f... | Portuguese man o' war | Wikipedia | 332 | 152952 | https://en.wikipedia.org/wiki/Portuguese%20man%20o%27%20war | Biology and health sciences | Cnidarians | Animals |
The Portuguese man o' war is asymmetrically shaped: the zooids hang down from either the right or left side of the midline of the pneumatophore or bladder. The pneumatophore can be oriented towards the left or the right. This phenomenon may be an adaptation that prevents an entire population from being washed on shore ... | Portuguese man o' war | Wikipedia | 301 | 152952 | https://en.wikipedia.org/wiki/Portuguese%20man%20o%27%20war | Biology and health sciences | Cnidarians | Animals |
Mathematical modelling
Since they have no propulsion system, the movement of the man o' war can be modelled mathematically by calculating the forces acting on it, or by advecting virtual particles in ocean and atmospheric circulation models. Earlier studies modelled the movement of the man o' war with Lagrangian partic... | Portuguese man o' war | Wikipedia | 375 | 152952 | https://en.wikipedia.org/wiki/Portuguese%20man%20o%27%20war | Biology and health sciences | Cnidarians | Animals |
A eutectic system or eutectic mixture ( ) is a type of a homogeneous mixture that has a melting point lower than those of the constituents. The lowest possible melting point over all of the mixing ratios of the constituents is called the eutectic temperature. On a phase diagram, the eutectic temperature is seen as the ... | Eutectic system | Wikipedia | 505 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Non-eutectic compositions
Compositions of eutectic systems that are not at the eutectic point can be classified as hypoeutectic or hypereutectic:
Hypoeutectic compositions are those with a greater composition of species α and a smaller percent composition of species β than the eutectic composition (E)
Hypereutect... | Eutectic system | Wikipedia | 275 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Some uses for eutectic alloys include:
NEMA eutectic alloy overload relays for electrical protection of three-phase motors for pumps, fans, conveyors, and other factory process equipment.
Eutectic alloys for soldering, both traditional alloys composed of lead (Pb) and tin (Sn), sometimes with additional silver (Ag) or ... | Eutectic system | Wikipedia | 292 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Sodium chloride and water form a eutectic mixture whose eutectic point is −21.2 °C and 23.3% salt by mass. The eutectic nature of salt and water is exploited when salt is spread on roads to aid snow removal, or mixed with ice to produce low temperatures (for example, in traditional ice cream making).
Ethanol–water has... | Eutectic system | Wikipedia | 401 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Alloys
The primary strengthening mechanism of the eutectic structure in metals is composite strengthening (See strengthening mechanisms of materials). This deformation mechanism works through load transfer between the two constituent phases where the more compliant phase transfers stress to the stiffer phase. By takin... | Eutectic system | Wikipedia | 424 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Strengthening metallic eutectic phases to resist deformation at high temperatures (see creep deformation) is more convoluted as the primary deformation mechanism changes depending on the level of stress applied. At high temperatures where deformation is dominated by dislocation movement, the strengthening from load tra... | Eutectic system | Wikipedia | 461 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
At the peritectic decomposition temperature the compound, rather than melting, decomposes into another solid compound and a liquid. The proportion of each is determined by the lever rule. In the Al-Au phase diagram, for example, it can be seen that only two of the phases melt congruently, AuAl2 and Au2Al, while the res... | Eutectic system | Wikipedia | 81 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
"Bad solid solution"
Not all minimum melting point systems are "eutectic". The alternative of "poor solid solution" can be illustrated by comparing the common precious metal systems Cu-Ag and Cu-Au.
Cu-Ag, source for example https://himikatus.ru/art/phase-diagr1/Ag-Cu.php, is a true eutectic system. The eutectic meltin... | Eutectic system | Wikipedia | 439 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Unlike silver with fineness other than 719 (which melts partly at exactly 780 °C through a wide fineness range), gold with fineness other than 800 will reach solidus and start partial melting at a temperature different from and higher than 910 °C, depending on the alloy fineness. The partial melting does cause some com... | Eutectic system | Wikipedia | 383 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Eutectic calculation
The composition and temperature of a eutectic can be calculated from enthalpy and entropy of fusion of each components.
The Gibbs free energy G depends on its own differential:
Thus, the G/T derivative at constant pressure is calculated by the following equation:
The chemical potential is c... | Eutectic system | Wikipedia | 144 | 152969 | https://en.wikipedia.org/wiki/Eutectic%20system | Physical sciences | Phase separations | Chemistry |
Euglenids or euglenoids are one of the best-known groups of eukaryotic flagellates: single-celled organisms with flagella, or whip-like tails. They are classified in the phylum Euglenophyta, class Euglenida or Euglenoidea. Euglenids are commonly found in fresh water, especially when it is rich in organic materials, but... | Euglenid | Wikipedia | 353 | 152970 | https://en.wikipedia.org/wiki/Euglenid | Biology and health sciences | Excavata | Plants |
The first attempt at classifying euglenids was done by Ehrenberg in 1830, when he described the genus Euglena and placed it in the Polygastrica of family Astasiae, containing other creatures of variable body shape and lacking pseudopods or lorica. Later, various biologists described additional characteristics for Eugle... | Euglenid | Wikipedia | 385 | 152970 | https://en.wikipedia.org/wiki/Euglenid | Biology and health sciences | Excavata | Plants |
In addition, euglenids can be divided into inflexible or rigid euglenids, and flexible or metabolic euglenids which are capable of 'metaboly' or 'euglenid motion'. Only those with more than 18 protein strips in their pellicle gain this flexibility. Phylogenetic studies show that various clades of rigid phagotrophic eug... | Euglenid | Wikipedia | 482 | 152970 | https://en.wikipedia.org/wiki/Euglenid | Biology and health sciences | Excavata | Plants |
Nutrition
The classification of euglenids is still variable, as groups are being revised to conform with their molecular phylogeny. Classifications have fallen in line with the traditional groups based on differences in nutrition and number of flagella; these provide a starting point for considering euglenid diversity... | Euglenid | Wikipedia | 454 | 152970 | https://en.wikipedia.org/wiki/Euglenid | Biology and health sciences | Excavata | Plants |
For euglenids to reproduce, asexual reproduction takes place in the form of binary fission, and the cells replicate and divide during mitosis and cytokinesis. This process occurs in a very distinct order. First, the basal bodies and flagella replicate, then the cytostome and microtubules (the feeding apparatus), and fi... | Euglenid | Wikipedia | 214 | 152970 | https://en.wikipedia.org/wiki/Euglenid | Biology and health sciences | Excavata | Plants |
In topology, knot theory is the study of mathematical knots. While inspired by knots which appear in daily life, such as those in shoelaces and rope, a mathematical knot differs in that the ends are joined so it cannot be undone, the simplest knot being a ring (or "unknot"). In mathematical language, a knot is an embed... | Knot theory | Wikipedia | 495 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
A mathematical theory of knots was first developed in 1771 by Alexandre-Théophile Vandermonde who explicitly noted the importance of topological features when discussing the properties of knots related to the geometry of position. Mathematical studies of knots began in the 19th century with Carl Friedrich Gauss, who de... | Knot theory | Wikipedia | 440 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
A knot is created by beginning with a one-dimensional line segment, wrapping it around itself arbitrarily, and then fusing its two free ends together to form a closed loop . Simply, we can say a knot is a "simple closed curve" (see Curve) — that is: a "nearly" injective and continuous function , with the only "non-in... | Knot theory | Wikipedia | 512 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
A useful way to visualise and manipulate knots is to project the knot onto a plane—think of the knot casting a shadow on the wall. A small change in the direction of projection will ensure that it is one-to-one except at the double points, called crossings, where the "shadow" of the knot crosses itself once transversel... | Knot theory | Wikipedia | 496 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
A knot invariant is a "quantity" that is the same for equivalent knots . For example, if the invariant is computed from a knot diagram, it should give the same value for two knot diagrams representing equivalent knots. An invariant may take the same value on two different knots, so by itself may be incapable of dis... | Knot theory | Wikipedia | 504 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
C() = C() + z C()
gives a link deformable to one with 0 crossings (it is actually the unlink of two components) and an unknot. The unlink takes a bit of sneakiness:
C() = C() + z C()
which implies that C(unlink of two components) = 0, since the first two polynomials are of the unknot and thus equal.
Putting all th... | Knot theory | Wikipedia | 352 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
Geometry lets us visualize what the inside of a knot or link complement looks like by imagining light rays as traveling along the geodesics of the geometry. An example is provided by the picture of the complement of the Borromean rings. The inhabitant of this link complement is viewing the space from near the red compo... | Knot theory | Wikipedia | 455 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
Knotting spheres of higher dimension
Since a knot can be considered topologically a 1-dimensional sphere, the next generalization is to consider a two-dimensional sphere () embedded in 4-dimensional Euclidean space (). Such an embedding is knotted if there is no homeomorphism of onto itself taking the embedded 2-spher... | Knot theory | Wikipedia | 350 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
Two knots can be added by cutting both knots and joining the pairs of ends. The operation is called the knot sum, or sometimes the connected sum or composition of two knots. This can be formally defined as follows : consider a planar projection of each knot and suppose these projections are disjoint. Find a rectangle ... | Knot theory | Wikipedia | 395 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
Traditionally, knots have been catalogued in terms of crossing number. Knot tables generally include only prime knots, and only one entry for a knot and its mirror image (even if they are different) . The number of nontrivial knots of a given crossing number increases rapidly, making tabulation computationally difficu... | Knot theory | Wikipedia | 275 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
The first major verification of this work was done in the 1960s by John Horton Conway, who not only developed a new notation but also the Alexander–Conway polynomial . This verified the list of knots of at most 11 crossings and a new list of links up to 10 crossings. Conway found a number of omissions but only one dup... | Knot theory | Wikipedia | 316 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
Alexander–Briggs notation
This is the most traditional notation, due to the 1927 paper of James W. Alexander and Garland B. Briggs and later extended by Dale Rolfsen in his knot table (see image above and List of prime knots). The notation simply organizes knots by their crossing number. One writes the crossing number ... | Knot theory | Wikipedia | 459 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
The notation describes how to construct a particular link diagram of the link. Start with a basic polyhedron, a 4-valent connected planar graph with no digon regions. Such a polyhedron is denoted first by the number of vertices then a number of asterisks which determine the polyhedron's position on a list of basic poly... | Knot theory | Wikipedia | 501 | 153008 | https://en.wikipedia.org/wiki/Knot%20theory | Mathematics | Geometry | null |
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning,... | Heat exchanger | Wikipedia | 453 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Types
By maximum operating temperature, heat exchangers can be divided into low-temperature and high-temperature ones. The former work up to 500–650°C depending on the industry and generally don't require special design and material considerations. The latter work up to 1000 or even 1400°C.
Double pipe heat exchangers... | Heat exchanger | Wikipedia | 426 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Baffles are used to support the tubes, direct the fluid flow to the tubes in an approximately natural manner, and maximize the turbulence of the shell fluid. There are many various kinds of baffles, and the choice of baffle form, spacing, and geometry depends on the allowable flow rate of the drop in shell-side force, ... | Heat exchanger | Wikipedia | 112 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
In application to cool air with shell-and-tube technology (such as intercooler / charge air cooler for combustion engines), fins can be added on the tubes to increase heat transfer area on air side and create a tubes & fins configuration.
3. Plate Heat Exchanger
A plate heat exchanger contains an amount of thin sh... | Heat exchanger | Wikipedia | 500 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Furthermore, boilers are categorized as initial application of heat exchangers. The word steam generator was regularly used to describe a boiler unit where a hot liquid stream is the source of heat rather than the combustion products. Depending on the dimensions and configurations the boilers are manufactured. Several ... | Heat exchanger | Wikipedia | 74 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Shell and tube heat exchangers consist of a series of tubes which contain fluid that must be either heated or cooled. A second fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required. A set of tubes is called the tube bundle and can be made up of seve... | Heat exchanger | Wikipedia | 451 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Tube pitch: when designing the tubes, it is practical to ensure that the tube pitch (i.e., the centre-centre distance of adjoining tubes) is not less than 1.25 times the tubes' outside diameter. A larger tube pitch leads to a larger overall shell diameter, which leads to a more expensive heat exchanger.
Tube corrugati... | Heat exchanger | Wikipedia | 201 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Baffle Design: baffles are used in shell and tube heat exchangers to direct fluid across the tube bundle. They run perpendicularly to the shell and hold the bundle, preventing the tubes from sagging over a long length. They can also prevent the tubes from vibrating. The most common type of baffle is the segmental baffl... | Heat exchanger | Wikipedia | 406 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Fixed tube liquid-cooled heat exchangers especially suitable for marine and harsh applications can be assembled with brass shells, copper tubes, brass baffles, and forged brass integral end hubs. (See: Copper in heat exchangers).
Plate
Another type of heat exchanger is the plate heat exchanger. These exchangers are c... | Heat exchanger | Wikipedia | 509 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Adiabatic wheel
A fourth type of heat exchanger uses an intermediate fluid or solid store to hold heat, which is then moved to the other side of the heat exchanger to be released. Two examples of this are adiabatic wheels, which consist of a large wheel with fine threads rotating through the hot and cold fluids, and fl... | Heat exchanger | Wikipedia | 413 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
A stack of evenly-spaced metal plates act as the fins and the tubes are pressed through pre-cut holes in the fins, good thermal contact usually being achieved by deformation of the fins around the tube. This is typical construction for HVAC air coils and large refrigeration condensers.
Fins are spiral-wound onto indiv... | Heat exchanger | Wikipedia | 494 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Large systems with high volume and temperature gas streams, typical in industry, can benefit from steam Rankine cycle (SRC) in a waste heat recovery unit, but these cycles are too expensive for small systems. The recovery of heat from low temperature systems requires different working fluids than steam.
An organic Ran... | Heat exchanger | Wikipedia | 441 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
In the nuclear power plants called pressurized water reactors, special large heat exchangers pass heat from the primary (reactor plant) system to the secondary (steam plant) system, producing steam from water in the process. These are called steam generators. All fossil-fueled and nuclear power plants using steam-drive... | Heat exchanger | Wikipedia | 362 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Microchannel
Microchannel heat exchangers are multi-pass parallel flow heat exchangers consisting of three main elements: manifolds (inlet and outlet), multi-port tubes with the hydraulic diameters smaller than 1mm, and fins. All the elements usually brazed together using controllable atmosphere brazing process. Micro... | Heat exchanger | Wikipedia | 368 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
On the liquid side of these heat exchangers, the common fluids are water, a water-glycol solution, steam, or a refrigerant. For heating coils, hot water and steam are the most common, and this heated fluid is supplied by boilers, for example. For cooling coils, chilled water and refrigerant are most common. Chilled wat... | Heat exchanger | Wikipedia | 496 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Although double-pipe heat exchangers are the simplest to design, the better choice in the following cases would be the helical-coil heat exchanger (HCHE):
The main advantage of the HCHE, like that for the Spiral heat exchanger (SHE), is its highly efficient use of space, especially when it's limited and not enough str... | Heat exchanger | Wikipedia | 478 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
The main advantage of the SHE is its highly efficient use of space. This attribute is often leveraged and partially reallocated to gain other improvements in performance, according to well known tradeoffs in heat exchanger design. (A notable tradeoff is capital cost vs operating cost.) A compact SHE may be used to ha... | Heat exchanger | Wikipedia | 380 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
There are three main types of flows in a spiral heat exchanger:
Counter-current Flow: Fluids flow in opposite directions. These are used for liquid-liquid, condensing and gas cooling applications. Units are usually mounted vertically when condensing vapour and mounted horizontally when handling high concentrations of... | Heat exchanger | Wikipedia | 462 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Small-diameter coil technologies are becoming more popular in modern air conditioning and refrigeration systems because they have better rates of heat transfer than conventional sized condenser and evaporator coils with round copper tubes and aluminum or copper fin that have been the standard in the HVAC industry. Smal... | Heat exchanger | Wikipedia | 471 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Crude Oil Exchanger Fouling. In commercial crude oil refining, crude oil is heated from to prior to entering the distillation column. A series of shell and tube heat exchangers typically exchange heat between crude oil and other oil streams to heat the crude to prior to heating in a furnace. Fouling occurs on the cr... | Heat exchanger | Wikipedia | 480 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Design and manufacturing codes include: ASME Boiler and Pressure Vessel Code (US); PD 5500 (UK); BS 1566 (UK); EN 13445 (EU); CODAP (French); Pressure Equipment Safety Regulations 2016 (PER) (UK); Pressure Equipment Directive (EU); NORSOK (Norwegian); TEMA; API 12; and API 560.
In nature
Humans
The human nasal passag... | Heat exchanger | Wikipedia | 489 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
In industry
Heat exchangers are widely used in industry both for cooling and heating large scale industrial processes. The type and size of heat exchanger used can be tailored to suit a process depending on the type of fluid, its phase, temperature, density, viscosity, pressures, chemical composition and various other ... | Heat exchanger | Wikipedia | 463 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
Temperature profiles for the pipes are and where x is the distance along the pipe. Assume a steady state, so that the temperature profiles are not functions of time. Assume also that the only transfer of heat from a small volume of fluid in one pipe is to the fluid element in the other pipe at the same position, i.e.... | Heat exchanger | Wikipedia | 507 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
By the conservation of energy, the sum of the two energies is zero. The quantity is known as the Log mean temperature difference, and is a measure of the effectiveness of the heat exchanger in transferring heat energy. | Heat exchanger | Wikipedia | 43 | 153221 | https://en.wikipedia.org/wiki/Heat%20exchanger | Technology | Heating and cooling | null |
In numerical analysis, a root-finding algorithm is an algorithm for finding zeros, also called "roots", of continuous functions. A zero of a function is a number such that . As, generally, the zeros of a function cannot be computed exactly nor expressed in closed form, root-finding algorithms provide approximations t... | Root-finding algorithm | Wikipedia | 341 | 153299 | https://en.wikipedia.org/wiki/Root-finding%20algorithm | Mathematics | Real analysis | null |
The behavior of general root-finding algorithms is studied in numerical analysis. However, for polynomials specifically, the study of root-finding algorithms belongs to computer algebra, since algebraic properties of polynomials are fundamental for the most efficient algorithms. The efficiency and applicability of an a... | Root-finding algorithm | Wikipedia | 481 | 153299 | https://en.wikipedia.org/wiki/Root-finding%20algorithm | Mathematics | Real analysis | null |
False position (regula falsi)
The false position method, also called the regula falsi method, is similar to the bisection method, but instead of using bisection search's middle of the interval it uses the -intercept of the line that connects the plotted function values at the endpoints of the interval, that is
False... | Root-finding algorithm | Wikipedia | 482 | 153299 | https://en.wikipedia.org/wiki/Root-finding%20algorithm | Mathematics | Real analysis | null |
Interpolating two values yields a line: a polynomial of degree one. This is the basis of the secant method. Regula falsi is also an interpolation method that interpolates two points at a time but it differs from the secant method by using two points that are not necessarily the last two computed points. Three values de... | Root-finding algorithm | Wikipedia | 470 | 153299 | https://en.wikipedia.org/wiki/Root-finding%20algorithm | Mathematics | Real analysis | null |
Fixed point iteration method
We can use the fixed-point iteration to find the root of a function. Given a function which we have set to zero to find the root (), we rewrite the equation in terms of so that becomes (note, there are often many functions for each function). Next, we relabel each side of the equatio... | Root-finding algorithm | Wikipedia | 476 | 153299 | https://en.wikipedia.org/wiki/Root-finding%20algorithm | Mathematics | Real analysis | null |
The Poincaré–Miranda theorem gives a criterion for the existence of a root in a rectangle, but it is hard to verify because it requires evaluating the function on the entire boundary of the rectangle.
Another criterion is given by a theorem of Kronecker. It says that, if the topological degree of a function f on a rec... | Root-finding algorithm | Wikipedia | 245 | 153299 | https://en.wikipedia.org/wiki/Root-finding%20algorithm | Mathematics | Real analysis | null |
Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy, and one of the 88 modern constellations. Located in the northern celestial hemisphere, it is named for Andromeda, daughter of Cassiopeia, in the Greek myth, who was chained to a rock to be eaten by the sea monster Cetus... | Andromeda (constellation) | Wikipedia | 451 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
The uranography of Andromeda has its roots most firmly in the Greek tradition, though a female figure in Andromeda's location had appeared earlier in Babylonian astronomy. The stars that make up Pisces and the middle portion of modern Andromeda formed a constellation representing a fertility goddess, sometimes named as... | Andromeda (constellation) | Wikipedia | 469 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
Andromeda was one of the original 48 constellations formulated by Ptolemy in his 2nd-century Almagest, in which it was defined as a specific pattern of stars. She is typically depicted with α Andromedae as her head, ο and λ Andromedae as her chains, and δ, π, μ, β, and γ her body and legs. However, there is no universa... | Andromeda (constellation) | Wikipedia | 351 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
In traditional Chinese astronomy, nine stars from Andromeda (including Beta Andromedae, Mu Andromedae, and Nu Andromedae), along with seven stars from Pisces, formed an elliptical constellation called "Legs" (奎宿). This constellation either represented the foot of a walking person or a wild boar. Gamma Andromedae and it... | Andromeda (constellation) | Wikipedia | 463 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
Andromeda is also associated with the Mesopotamian creation story of Tiamat, the goddess of Chaos. She bore many demons for her husband, Apsu, but eventually decided to destroy them in a war that ended when Marduk killed her. He used her body to create the constellations as markers of time for humans.
In the Marshall ... | Andromeda (constellation) | Wikipedia | 190 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
α And (Alpheratz, Sirrah) is the brightest star in this constellation. It is an A0p class binary star with an overall apparent visual magnitude of 2.1 and a luminosity of . It is 97 light-years from Earth. It represents Andromeda's head in Western mythology, however, the star's traditional Arabic names – Alpheratz and ... | Andromeda (constellation) | Wikipedia | 325 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
γ And (Almach) is an orange-hued bright giant star of type K3 found at the southern tip of the constellation with an overall magnitude of 2.14. Almach is a multiple star with a yellow primary of magnitude 2.3 and a blue-green secondary of magnitude 5, separated by 9.7 arcseconds. British astronomer William Herschel sai... | Andromeda (constellation) | Wikipedia | 440 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
υ And (Titawin) is a magnitude 4.1 binary system that consists of one F-type dwarf and an M-type dwarf. The primary star has a planetary system with 4 confirmed planets, 0.96 times, 14.57 times, 10.19 times and 1.06 the mass of Jupiter. The system is 44 light-years from Earth.
ξ And (Adhil) is a binary star 217 light-... | Andromeda (constellation) | Wikipedia | 450 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
14 And (Veritate) is a yellow-hued giant star of type G8 that is 251 light-years away. It has a mass of and a radius of . It has one planet, 14 Andromedae b, discovered in 2008. It orbits at a distance of 0.83 astronomical units from its parent star every 186 days and has a mass of . | Andromeda (constellation) | Wikipedia | 77 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
Of the stars brighter than 4th magnitude (and those with measured luminosity), Andromeda has a relatively even distribution of evolved and main-sequence stars.
Deep-sky objects
Andromeda's borders contain many visible distant galaxies. The most famous deep-sky object in Andromeda is the spiral galaxy cataloged as Me... | Andromeda (constellation) | Wikipedia | 503 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
The Andromeda Galaxy's two main companions, M32 and M110 (also known as NGC 221 and NGC 205, respectively) are faint elliptical galaxies that lie near it. M32, visible with a far smaller size of 8.7 by 6.4 arcminutes, compared to M110, appears superimposed on the larger galaxy in a telescopic view as a hazy smudge, M11... | Andromeda (constellation) | Wikipedia | 464 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
Andromeda's most celebrated open cluster is NGC 752 (Caldwell 28) at an overall magnitude of 5.7. It is a loosely scattered cluster in the Milky Way that measures 49 arcminutes across and features approximately twelve bright stars, although more than 60 stars of approximately 9th magnitude become visible at low magnifi... | Andromeda (constellation) | Wikipedia | 291 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
Meteor showers
Each November, the Andromedids meteor shower appears to radiate from Andromeda. The shower peaks in mid-to-late November every year, but has a low peak rate of fewer than 2 meteors per hour. Astronomers have often associated the Andromedids with Biela's Comet, which was destroyed in the 19th century, bu... | Andromeda (constellation) | Wikipedia | 297 | 153353 | https://en.wikipedia.org/wiki/Andromeda%20%28constellation%29 | Physical sciences | Other | Astronomy |
Fish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or ps... | Fish farming | Wikipedia | 504 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Extensive aquaculture is the other form of fish farming. Extensive aquaculture is more basic than intensive aquaculture in that less effort is put into the husbandry of the fish. Extensive aquaculture is done in the ocean, natural and man-made lakes, bays, rivers, and Fiords. Fish are contained within these habitats by... | Fish farming | Wikipedia | 475 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
In these kinds of systems fish production per unit of surface can be increased at will, as long as sufficient oxygen, fresh water and food are provided. Because of the requirement of sufficient fresh water, a massive water purification system must be integrated in the fish farm. One way to achieve this is to combine hy... | Fish farming | Wikipedia | 396 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
The risk of infections by parasites such as fish lice, fungi (Saprolegnia spp.), intestinal worms (such as nematodes or trematodes), bacteria (e.g., Yersinia spp., Pseudomonas spp.), and protozoa (such as dinoflagellates) is similar to that in animal husbandry, especially at high population densities. However, animal h... | Fish farming | Wikipedia | 508 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Fish cages are placed in lakes, bayous, ponds, rivers, or oceans to contain and protect fish until they can be harvested. The method is also called "off-shore cultivation" when the cages are placed in the sea. They can be constructed of a wide variety of components. Fish are stocked in cages, artificially fed, and harv... | Fish farming | Wikipedia | 461 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Recently, copper alloys have become important netting materials in aquaculture. Copper alloys are antimicrobial, that is, they destroy bacteria, viruses, fungi, algae, and other microbes. In the marine environment, the antimicrobial/algaecidal properties of copper alloys prevent biofouling, which can briefly be describ... | Fish farming | Wikipedia | 431 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
A good interchange of water and also a high replacement of bottom water.
At all depths should be a good current condition. This is necessary because the organic particles should be able to be carried away using the current.
A gravel and sand bottom are qualified for fish farming, although bottoms with silt and mud ar... | Fish farming | Wikipedia | 465 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Composite fish culture
The composite fish culture system is a technology developed in India by the Indian Council of Agricultural Research in the 1970s. In this system, of both local and imported fish, a combination of five or six fish species is used in a single fish pond. These species are selected so that they do n... | Fish farming | Wikipedia | 485 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
This system, properly tuned, produces more edible protein per unit area than any other. A wide variety of plants can grow well in the hydroponic beds. Most growers concentrate on herbs (e.g. parsley and basil), which command premium prices in small quantities all year long. The most common customers are restaurant whol... | Fish farming | Wikipedia | 464 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Farmed fish are usually raised in overcrowded environments, making them susceptible to stress, injuries, aggression and diseases. These conditions prevent them from engaging in natural behaviors such as nesting or migration. Overcrowding often leads to poor water quality due to fish waste and antibiotics use. Sea lice ... | Fish farming | Wikipedia | 438 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
In 2014, Martinez-Rubio et al. conducted a study in which cardiomyopathy syndrome (CMS), a severe cardiac disease in Atlantic salmon (Salmo salar), was investigated pertaining the effects of functional feeds with reduced lipid content and increased eicosapentaenoic acid levels in controlling CMS in salmon after infecti... | Fish farming | Wikipedia | 427 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Parasites and disease
Sea lice, particularly Lepeophtheirus salmonis and various Caligus species, including C. clemensi and C. rogercresseyi, can cause deadly infestations of both farm-grown and wild salmon. Sea lice are ectoparasites which feed on mucus, blood, and skin, and migrate and latch onto the skin of wild sa... | Fish farming | Wikipedia | 494 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Because of parasite problems, some aquaculture operators frequently use strong antibiotic drugs to keep the fish alive, but many fish still die prematurely at rates up to 30%. Additionally, other common drugs used in salmonid fish farms in North America and Europe include anesthetic, chemotherapeutic, and anthelmintic ... | Fish farming | Wikipedia | 414 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Siting
If aquaculture farms are placed in an area with strong current, pollutants can be flushed out of the area fairly quickly. This helps manage the pollution problem and also aids in overall fish growth.
Concern remains that resultant bacterial growth fertilised by fish faeces strips the water of oxygen, reducing o... | Fish farming | Wikipedia | 446 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
In 2008, the US National Organic Standards Board allowed farmed fish to be labeled as organic provided less than 25% of their feed came from wild fish. This decision was criticized by the advocacy group Food & Water Watch as "bending the rules" about organic labeling. In the European Union, fish labeling as to species,... | Fish farming | Wikipedia | 404 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
From 2011, a team from the University of Waterloo led by Tahbit Chowdhury and Gordon Graff examined vertical RAS aquaculture designs aimed at producing protein-rich fish species. However, because of its high capital and operating costs, RAS has generally been restricted to practices such as broodstock maturation, larva... | Fish farming | Wikipedia | 262 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
Inhumane methods
According to T. Håstein of the National Veterinary Institute (Oslo, Norway), "Different methods for slaughter of fish are in place and it is no doubt that many of them may be considered as appalling from an animal welfare point of view." A 2004 report by the EFSA Scientific Panel on Animal Health and ... | Fish farming | Wikipedia | 331 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
More humane methods
Proper stunning renders the fish unconscious immediately and for a sufficient period of time such that the fish is killed in the slaughter process (e.g. through exsanguination) without regaining consciousness.
Percussive stunning involves rendering the fish unconscious with a blow on the head.
El... | Fish farming | Wikipedia | 197 | 153520 | https://en.wikipedia.org/wiki/Fish%20farming | Technology | Aquaculture | null |
A plastid is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids are considered to be intracellular endosymbiotic cyanobacteria.
Examples of plastids include chloroplasts (used for photosynthesis); chromoplasts (used for synthesis and storage of pigments); leuc... | Plastid | Wikipedia | 466 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
Chloroplasts, proplastids, and differentiation
In land plants, the plastids that contain chlorophyll can perform photosynthesis, thereby creating internal chemical energy from external sunlight energy while capturing carbon from Earth's atmosphere and furnishing the atmosphere with life-giving oxygen. These are the chl... | Plastid | Wikipedia | 508 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
Plastomes and Chloroplast DNA/ RNA; plastid DNA and plastid nucleoids
Each plastid creates multiple copies of its own unique genome, or plastome, (from 'plastid genome')which for a chlorophyll plastid (or chloroplast) is equivalent to a 'chloroplast genome', or a 'chloroplast DNA'. The number of genome copies produced... | Plastid | Wikipedia | 377 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
Where the proplastid (undifferentiated plastid) contains a single nucleoid region located near the centre of the proplastid, the developing (or differentiating) plastid has many nucleoids localized at the periphery of the plastid and bound to the inner envelope membrane. During the development/ differentiation of propl... | Plastid | Wikipedia | 417 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
Chloroplasts: found in green algae (plants) and other organisms that derived their genomes from green algae.
Muroplasts: also known as cyanoplasts or cyanelles, the plastids of glaucophyte algae are similar to plant chloroplasts, excepting they have a peptidoglycan cell wall that is similar to that of bacteria.
Rhodo... | Plastid | Wikipedia | 479 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
In normal intraspecific crossingsresulting in normal hybrids of one speciesthe inheriting of plastid DNA appears to be strictly uniparental; i.e., from the female. In interspecific hybridisations, however, the inheriting is apparently more erratic. Although plastids are inherited mainly from the female in interspecific... | Plastid | Wikipedia | 303 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
Origin
Plastids are thought to be descended from endosymbiotic cyanobacteria. The primary endosymbiotic event of the Archaeplastida is hypothesized to have occurred around 1.5 billion years ago and enabled eukaryotes to carry out oxygenic photosynthesis. Three evolutionary lineages in the Archaeplastida have since emer... | Plastid | Wikipedia | 386 | 153522 | https://en.wikipedia.org/wiki/Plastid | Biology and health sciences | Plant cells | null |
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