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Gelation According to the Carothers equation number-average degree of polymerization formula_1 is given by formula_2 where formula_3 is the extent of the reaction and formula_4 is the average functionality of reaction mixture. For the gel formula_1 can be considered to be infinite, thus the critical extent of the react... | https://en.wikipedia.org/wiki?curid=21301778 |
Gelation This relation yields to an expression for the extent of reaction of A functional groups at the gel point formula_21 where r is the ratio of all A groups to all B groups. If more than one type of multifunctional branch unit is present and average formula_13 value is used for all monomer molecules with functiona... | https://en.wikipedia.org/wiki?curid=21301778 |
UV pinning is the process of applying a dose of low intensity ultraviolet (UV) light to a UV curable ink (UV ink). The light's wavelengths must be correctly matched to the ink’s photochemical properties. As a result, the ink droplets move to a higher viscosity state, but stop short of full cure. This is also referred t... | https://en.wikipedia.org/wiki?curid=21319825 |
Tetrafluoropropene may refer to: | https://en.wikipedia.org/wiki?curid=21321296 |
Leiv Kristen Sydnes (born 9 July 1948) is a Norwegian chemist, specializing in organic chemistry. He was born in Haugesund, and took his education at the University of Oslo. He has the dr.philos. degree from 1978. He was hired as an associate professor at the University of Tromsø in 1978, and was later promoted to prof... | https://en.wikipedia.org/wiki?curid=21323011 |
Graphane is a two-dimensional polymer of carbon and hydrogen with the formula unit (CH) where "n" is large. should not be confused with graphene, a two-dimensional form of carbon alone. is a form of hydrogenated graphene. Graphane's carbon bonds are in "sp" configuration, as opposed to graphene's "sp" bond configuratio... | https://en.wikipedia.org/wiki?curid=21330156 |
Graphane Hydrogenation of graphene on substrate affects only one side, preserving hexagonal symmetry. One-sided hydrogenation of graphene is possible due to the existence of ripplings. Because the latter are distributed randomly, the obtained material is disordered in contrast to two-sided graphane. Annealing allows th... | https://en.wikipedia.org/wiki?curid=21330156 |
Pre-B-cell leukemia homeobox (PBX) refers to a family of transcription factors. Types include: | https://en.wikipedia.org/wiki?curid=21332803 |
Journal of AOAC International The is a peer-reviewed scientific journal covering analytical chemistry. | https://en.wikipedia.org/wiki?curid=21339267 |
Physical properties of greenhouse gases Physical properties of greenhouse gases | https://en.wikipedia.org/wiki?curid=21340910 |
Tetrafluoropropylene may refer to: This is a Gaseous phase effluent from the decomposition of Teflon when laser cutting it. | https://en.wikipedia.org/wiki?curid=21341062 |
Kurt Peters Kurt Gustav Karl Peters (17 August 1897 – 23 May 1978) was an Austrian chemist. His work focused on the area of fuel technology, physical chemistry and catalytic reactions as well as the separation of rare gases and hydrocarbons. After serving in the Austrian army during World War I, he studied chemistry at... | https://en.wikipedia.org/wiki?curid=21344722 |
Materials Science and Engineering R: Reports is a monthly peer-reviewed scientific journal. It is the review section of "Materials Science and Engineering" and is published by Elsevier. It was established in 1993, when the journal "Materials Science Reports" was split into "Materials Science and Engineering C" and "Mat... | https://en.wikipedia.org/wiki?curid=21346408 |
Anomalous scattering In X-ray crystallography, anomalous scattering refers to a change in a diffracting X-ray’s phase that is unique from the rest of the atoms in a crystal due to strong X-ray absorbance. The amount of energy that individual atoms absorb depends on their atomic number. The relatively light atoms found ... | https://en.wikipedia.org/wiki?curid=21346659 |
Surface Science Reports is a peer-reviewed scientific journal published by North-Holland that covers the physics and chemistry of surfaces. It was established in 1981. It is the review journal corresponding to the journals "Surface Science" and "Surface Science Letters". This journal is abstracted and indexed by: Accor... | https://en.wikipedia.org/wiki?curid=21347279 |
Chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds. Two atoms of the same element bonded in a molecule do not form a chemical compound, since this would require two differ... | https://en.wikipedia.org/wiki?curid=21347411 |
Chemical compound It follows from their being composed of fixed proportions of two or more types of atoms that chemical compounds can be converted, via chemical reaction, into compounds or substances each having fewer atoms. The ratio of each element in the compound is expressed in a ratio in its chemical formula. A ch... | https://en.wikipedia.org/wiki?curid=21347411 |
Chemical compound Pure chemical elements are generally not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms (such as in the diatomic molecule H, or the polyatomic molecule S, etc.). Many chemical compounds have a unique numerical ... | https://en.wikipedia.org/wiki?curid=21347411 |
Chemical compound Other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Compounds are held together through a variety of different types of bonding and forces. The differences in the types o... | https://en.wikipedia.org/wiki?curid=21347411 |
Chemical compound Ionic bonding occurs when valence electrons are completely transferred between elements. Opposite to covalent bonding, this chemical bond creates two oppositely charged ions. The metals in ionic bonding usually lose their valence electrons, becoming a positively charged cation. The nonmetal will gain ... | https://en.wikipedia.org/wiki?curid=21347411 |
Greenhouse gas A greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect on planets. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane (), nitrous oxide (), a... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas 6°F), which the United Nations' Intergovernmental Panel on Climate Change (IPCC) designated as the upper limit to avoid "dangerous" levels, by 2036. The major constituents of Earth's atmosphere, nitrogen ()(78%), oxygen ()(21%), and argon (Ar)(0.9%), are not greenhouse gases because molecules containing ... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas In order, the most abundant greenhouse gases in Earth's atmosphere are: Atmospheric concentrations are determined by the balance between sources (emissions of the gas from human activities and natural systems) and sinks (the removal of the gas from the atmosphere by conversion to a different chemical com... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas 7 microns, or 2145 cm), where the emission of radiant energy from Earth's surface is at least a factor of ten lower. Oxidation of methane to , which requires reactions with the OH radical, produces an instantaneous reduction in radiative absorption and emission since is a weaker greenhouse gas than metha... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas The same process that converts NMVOCs to carbon dioxide can also lead to the formation of tropospheric ozone. Halocarbons have an indirect effect because they destroy stratospheric ozone. Finally, hydrogen can lead to ozone production and increases as well as producing stratospheric water vapor. The majo... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas When ranked by their direct contribution to the greenhouse effect, the most important are: In addition to the main greenhouse gases listed above, other greenhouse gases include sulfur hexafluoride, hydrofluorocarbons and perfluorocarbons (see IPCC list of greenhouse gases). Some greenhouse gases are not ... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Mathematically formula_1 can be defined as the ratio of the mass formula_3 (in kg) of X in the box to its removal rate, which is the sum of the flow of X out of the box (formula_4), chemical loss of X (formula_5), and deposition of X (all in kg/s): formula_7. If output of this gas into the box ceased, th... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Earth absorbs some of the radiant energy received from the sun, reflects some of it as light and reflects or radiates the rest back to space as heat. Earth's surface temperature depends on this balance between incoming and outgoing energy. If this energy balance is shifted, Earth's surface becomes warmer... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Conversely, if a molecule has a longer atmospheric lifetime than its GWP will increase when the timescale is considered. Carbon dioxide is defined to have a GWP of 1 over all time periods. Methane has an atmospheric lifetime of 12 ± 3 years. The 2007 IPCC report lists the GWP as 72 over a time scale of 2... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas The 2007 Fourth Assessment Report compiled by the IPCC (AR4) noted that "changes in atmospheric concentrations of greenhouse gases and aerosols, land cover and solar radiation alter the energy balance of the climate system", and concluded that "increases in anthropogenic greenhouse gas concentrations is ... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Indeed, higher concentrations are thought to have prevailed throughout most of the Phanerozoic eon, with concentrations four to six times current concentrations during the Mesozoic era, and ten to fifteen times current concentrations during the early Palaeozoic era until the middle of the Devonian period... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Measurements from Antarctic ice cores show that before industrial emissions started atmospheric mole fractions were about 280 parts per million (ppm), and stayed between 260 and 280 during the preceding ten thousand years. Carbon dioxide mole fractions in the atmosphere have gone up by approximately 35 p... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Recent data also shows that the concentration is increasing at a higher rate. In the 1960s, the average annual increase was only 37% of what it was in 2000 through 2007. Total cumulative emissions from 1870 to 2017 were 425±20 GtC (1539 GtCO) from fossil fuels and industry, and 180±60 GtC (660 GtCO) from... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas The atmospheric concentration of vapor is highly variable and depends largely on temperature, from less than 0.01% in extremely cold regions up to 3% by mass in saturated air at about 32 °C. (See Relative humidity#other important facts.) The average residence time of a water molecule in the atmosphere is... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Natural sources of carbon dioxide are more than 20 times greater than sources due to human activity, but over periods longer than a few years natural sources are closely balanced by natural sinks, mainly photosynthesis of carbon compounds by plants and marine plankton. As a result of this balance, the at... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas The Cancún agreement, agreed on in 2010, includes voluntary pledges made by 76 countries to control emissions. At the time of the agreement, these 76 countries were collectively responsible for 85% of annual global emissions. Although CFCs are greenhouse gases, they are regulated by the Montreal Protocol... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Thus emissions arising from energy production may be categorised according to where they are emitted, or where the resulting energy is consumed. If emissions are attributed at the point of production, then electricity generators contribute about 25% of global greenhouse gas emissions. If these emissions ... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas The number of international travelers is expected to increase from 594 million in 1996 to 1.6 billion by 2020, adding greatly to the problem unless steps are taken to reduce emissions. The trucking and haulage industry plays a part in production of , contributing around 20% of the UK's total carbon emiss... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas According to the report plastic will contribute greenhouse gases in the equivalent of 850 million tonnes of carbon dioxide (CO) to the atmosphere in 2019. In current trend, annual emissions will grow to 1.34 billion tonnes by 2030. By 2050 plastic could emit 56 billion tonnes of emissions, as much as 14 ... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas There are arguments for the adoption of a common measurement tool, or at least the development of communication between different tools. Emissions may be measured over long time periods. This measurement type is called historical or cumulative emissions. Cumulative emissions give some indication of who i... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Another measurement is of per capita emissions. This divides a country's total annual emissions by its mid-year population. Per capita emissions may be based on historical or annual emissions (Banuri "et al.", 1996, pp. 106–07). While cities are sometimes considered to be disproportionate contributors to... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Emission intensities may be calculated using market exchange rates (MER) or purchasing power parity (PPP) (Banuri "et al.", 1996, p. 96). Calculations based on MER show large differences in intensities between developed and developing countries, whereas calculations based on PPP show smaller differences.... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas Over this time period, the US accounted for 28% of emissions; the EU, 23%; Russia, 11%; China, 9%; other OECD countries, 5%; Japan, 4%; India, 3%; and the rest of the world, 18%. Between 1970 and 2004, global growth in annual emissions was driven by North America, Asia, and the Middle East. The sharp acc... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas These countries have a long history of emissions (see the section on Cumulative and historical emissions). Annual per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries. Due to China's fast economic development, its annual per capita em... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas In 2009, the annual top ten emitting countries accounted for about two-thirds of the world's annual energy-related emissions. One way of attributing greenhouse gas emissions is to measure the embedded emissions (also referred to as "embodied emissions") of goods that are being consumed. Emissions are usu... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas , are imported or exported) from one country to another. Major developed economies were found to be typically net importers of embodied carbon emissions—with UK consumption emissions 34% higher than production emissions, and Germany (29%), Japan (19%) and the US (13%) also significant net importers of em... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas 5 thousand Tg -eq is measured against a hypothetical "baseline" of Annex I emissions, i.e., projected Annex I emissions in the absence of policies and measures. The total projected Annex I saving of 1.5 thousand -eq does not include emissions savings in seven of the Annex I Parties. A wide range of proje... | https://en.wikipedia.org/wiki?curid=21350772 |
Greenhouse gas A 2011 IPCC report included a literature review of numerous energy sources' total life cycle emissions. Below are the emission values that fell at the 50th percentile of all studies surveyed. Greenhouse gases can be removed from the atmosphere by various processes, as a consequence of: A number of techno... | https://en.wikipedia.org/wiki?curid=21350772 |
Clinical Chemistry (journal) Clinical Chemistry is a peer-reviewed medical journal covering the field of clinical chemistry. It is the official journal of the American Association for Clinical Chemistry. The journal was first published in 1955 on a bi-monthly basis "to raise the level at which chemistry is practiced in... | https://en.wikipedia.org/wiki?curid=21355397 |
Ub-AMC Ubiquitin-AMC is a fluorogenic substrate for a wide range of deubiquitinating enzymes (DUBs), including ubiquitin C-terminal hydrolases (UCHs) and ubiquitin specific proteases (USPs). It is a particularly useful reagent for the study of deubiquitinating activity where detection sensitivity or continuous monitori... | https://en.wikipedia.org/wiki?curid=21359548 |
Nanoindenter A nanoindenter is the main component for indentation hardness tests used in nanoindentation. Since the mid-1970s nanoindentation has become the primary method for measuring and testing very small volumes of mechanical properties. Nanoindentation, also called "depth sensing indentation" or "instrumented ind... | https://en.wikipedia.org/wiki?curid=21370273 |
Nanoindenter The material for most nanoindenters is diamond and sapphire, although other hard materials can be used such as quartz, silicon, tungsten, steel, tungsten carbide and almost any other hard metal or ceramic material. Diamond is the most commonly used material for nanoindentation due to its properties of hard... | https://en.wikipedia.org/wiki?curid=21370273 |
List of instruments used in toxicology Instruments used specially in Toxicology are as follows: | https://en.wikipedia.org/wiki?curid=21370414 |
List of superconductors The table below shows some of the parameters of common superconductors. X:Y means material X doped with element Y, "T" is the highest reported transition temperature in kelvins and "H" is a critical magnetic field in tesla. "BCS" means whether or not the superconductivity is explained within the... | https://en.wikipedia.org/wiki?curid=21375423 |
Oxygen plant Oxygen plants are industrial systems designed to generate oxygen. They typically use air as a feedstock and separate it from other components of air using pressure swing adsorption or membrane separation techniques. Such plants are distinct from cryogenic separation plants which separate and capture all th... | https://en.wikipedia.org/wiki?curid=21376719 |
Oxygen plant In the oil and gas industry, oxygen finds application as a means for viscosity improvement and enhancement of oil-and-gas flow properties. Oxygen is also used for boosting production capacity of oil cracking plants, efficiency of high-octane components processing, as well as for the reduction of sulfuric d... | https://en.wikipedia.org/wiki?curid=21376719 |
Oxygen plant The oxygen plant flow process is arranged in such a way that highly absorbable gas mixture components are taken in by adsorbent, while low absorbable and non-absorbable components go through the plant. Today, there exist three methods of arranging the adsorption-based air separation process with the use of... | https://en.wikipedia.org/wiki?curid=21376719 |
Oxygen plant Where gaseous oxygen purity is required at the level of 90-95% with the capacity of up to 5,000 Nm per hour, adsorption oxygen plants are the optimal choice. This oxygen purity may also be obtained through the use of systems based on the cryogenic technology; however, cryogenic plants are more cumbersome a... | https://en.wikipedia.org/wiki?curid=21376719 |
Oxygen plant In the case of compressor technology, air is supplied into the fiber space under excess pressure, oxygen exits the membrane under slight excess pressure, and where necessary, is pressurized by booster compressor to the required pressure level. By the use of vacuum technology, a vacuum pump is used for the ... | https://en.wikipedia.org/wiki?curid=21376719 |
Oxygen plant Because of the plants high automation degree, no constant manned attendance is required during its operation. Membrane oxygen plants are finding increasingly broad application in various industries all over the world. With moderate requirements to oxygen purity in product - up to 30-45%, membrane systems g... | https://en.wikipedia.org/wiki?curid=21376719 |
Environmental engineering science (EES) is a multidisciplinary field of engineering science that combines the biological, chemical and physical sciences with the field of engineering. This major traditionally requires the student to take basic engineering classes in fields such as thermodynamics, advanced math, compute... | https://en.wikipedia.org/wiki?curid=21377293 |
Environmental engineering science Meanwhile, the environmental engineering science student will choose a direction for their career. From the range of electives they have to choose from, these students can move into a fields such as the design of nuclear storage facilities, bacterial bioreactors or environmental polici... | https://en.wikipedia.org/wiki?curid=21377293 |
Environmental engineering science Although an environmental engineering option exists within the civil engineering major, the engineering science curriculum provides a more broadly based foundation in the sciences than is possible in civil engineering At MIT, the major is described in their curriculum, including the fo... | https://en.wikipedia.org/wiki?curid=21377293 |
Environmental engineering science The program educational objectives of the EES program at the University of Florida are to produce engineering practitioners and graduate students who 3-5 years after graduation: Continue to learn, develop and apply their knowledge and skills to identify, prevent, and solve environmenta... | https://en.wikipedia.org/wiki?curid=21377293 |
Environmental engineering science This prepares the students for using their engineering and scientific knowledge to solve the interactions between plants, animals and the biosphere. This includes further education about microbial, molecular and cell biology. Classes can include cell biology, virology, microbial and pl... | https://en.wikipedia.org/wiki?curid=21377293 |
Limiting oxygen index The limiting oxygen index (LOI) is the minimum concentration of oxygen, expressed as a percentage, that will support combustion of a polymer. It is measured by passing a mixture of oxygen and nitrogen over a burning specimen, and reducing the oxygen level until a critical level is reached. LOI val... | https://en.wikipedia.org/wiki?curid=21391686 |
Microbiology (from Greek , "mīkros", "small"; , "bios", "life"; and , "-logia") is the study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology and ... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology The first recorded microscope observation was of the fruiting bodies of moulds, by Robert Hooke in 1666, but the Jesuit priest Athanasius Kircher was likely the first to see microbes, which he mentioned observing in milk and putrid material in 1658. Antonie van Leeuwenhoek is considered a father of microbi... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology " In the golden age of Islamic civilization, Iranian scientists hypothesized the existence of microorganisms, such as Avicenna in his book "The Canon of Medicine", Ibn Zuhr (also known as Avenzoar) who discovered scabies mites, and Al-Razi who gave the earliest known description of smallpox in his book "Th... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology " He also noted that putrid material is full of innumerable creeping animalcules. He published his "Scrutinium Pestis" (Examination of the Plague) in 1658, stating correctly that the disease was caused by microbes, though what he saw was most likely red or white blood cells rather than the plague agent its... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology Koch was one of the first scientists to focus on the isolation of bacteria in pure culture resulting in his description of several novel bacteria including "Mycobacterium tuberculosis", the causative agent of tuberculosis. While Pasteur and Koch are often considered the founders of microbiology, their work... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology The branches of microbiology can be classified into applied sciences, or divided according to taxonomy, as is the case with bacteriology, mycology, protozoology, virology and phycology. There is considerable overlap between the specific branches of microbiology with each other and with other disciplines, a... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology A variety of biopolymers, such as polysaccharides, polyesters, and polyamides, are produced by microorganisms. Microorganisms are used for the biotechnological production of biopolymers with tailored properties suitable for high-value medical application such as tissue engineering and drug delivery. Microo... | https://en.wikipedia.org/wiki?curid=21393077 |
Microbiology The ways the microbiome influences human and animal health, as well as methods to influence the microbiome are active areas of research. Research has suggested that microorganisms could be useful in the treatment of cancer. Various strains of non-pathogenic clostridia can infiltrate and replicate within so... | https://en.wikipedia.org/wiki?curid=21393077 |
Co-carcinogen A co-carcinogen is a chemical that promotes the effects of a carcinogen in the production of cancer. Usually, the term is used to refer to chemicals that are not carcinogenic on their own, such that an equivalent amount of the chemical is insufficient to initiate carcinogenesis. A chemical can be co-carci... | https://en.wikipedia.org/wiki?curid=21397857 |
Co-carcinogen Evidence points to beta carotene being one example of such a compound, which has led researchers to caution against the emphasis on isolated dietary supplements and instead recommend a focus on promoting a diverse diet rich in fruits and vegetables. The International Agency for Research on Cancer (IARC), ... | https://en.wikipedia.org/wiki?curid=21397857 |
Co-carcinogen Some myths even state beta carotene as elixir in developing countries (the Third World). With rising health consciousness, people rely on food supplements like vitamins A, B, C, D, E etc. these vitamins act as anti-oxidants chemical in the human body. Antioxidants is a good chemical in the appropriate con... | https://en.wikipedia.org/wiki?curid=21397857 |
Jennite is a calcium silicate hydrate mineral of general chemical formula: CaSiO(OH)·8HO. occurs as an alteration mineral in metamorphosed limestone and skarn. It typically occurs as vein and open space fillings as a late mineral phase. It also occurs in hydrated cement paste. A first specimen of jennite found in 1966 ... | https://en.wikipedia.org/wiki?curid=21399318 |
Nanobama is the name of microminiature portraits of United States President Barack Obama. They were created by Professor John Hart of University of Michigan's Mechanical Engineering department to celebrate the election of Obama. The portrait, which considered the world's smallest presidential portrait, measures 500 μm ... | https://en.wikipedia.org/wiki?curid=21399554 |
Platinum sterling Platinum Sterling is a registered trademark name of ABI Precious Metals, Inc. The trademark covers a range of alloys whose primary constituents are platinum and silver, primarily used in jewellery. The range of Platinum Sterling alloys was developed in 2003 by Marc Robinson, and its solder was created... | https://en.wikipedia.org/wiki?curid=21405254 |
Abelian sandpile model The Abelian sandpile model, also known as the Bak–Tang–Wiesenfeld model, was the first discovered example of a dynamical system displaying self-organized criticality. It was introduced by Per Bak, Chao Tang and Kurt Wiesenfeld in a 1987 paper. The model is a cellular automaton. In its original fo... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model The dynamics of the automaton at iteration formula_7 are then defined as follows: The toppling of several vertices during one iteration is referred to as an "avalanche". Every avalanche is guaranteed to eventually stop, i.e. after a finite number of topplings some stable configuration is reached ... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model The definition of the sandpile model given above for finite rectangular grids formula_2 of the standard square lattice formula_3 can then be seen as a special case of this definition: consider the graph formula_23 which is obtained from formula_35 by adding an additional vertex, the sink, and by ... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model It is easy to see that the "minimally stable configuration" formula_46, where every vertex carries formula_47 grains of sand, is reachable from any other stable configuration (add formula_48 grains to every vertex). Thus, equivalently, the recurrent configurations are exactly those configurations... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model Given a configuration formula_49, formula_50 for all formula_45, toppling unstable non-sink vertices on a finite connected graph until no unstable non-sink vertex remains leads to a unique "stable" configuration formula_52, which is called the "stabilization" of formula_49. Given two stable confi... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model Under the operation formula_72, the set of recurrent configurations forms an abelian group isomorphic to the cokernel of the reduced graph Laplacian formula_61, i.e. to formula_74, whereby formula_75 denotes the number of vertices (including the sink). More generally, the set of stable configurat... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model The original interest behind the model stemmed from the fact that in simulations on lattices, it is attracted to its critical state, at which point the correlation length of the system and the correlation time of the system go to infinity, without any fine tuning of a system parameter. This contr... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model The stabilization of chip configurations obeys a form of "least action principle": each vertex topples no more than necessary in the course of the stabilization. This can be formalized as follows. Call a sequence of topples "legal" if it only topples unstable vertices, and "stabilizing" if it res... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model The animation shows the recurrent configuration corresponding to the identity of the sandpile group on different formula_91 square grids of increasing sizes formula_92, whereby the configurations are rescaled to always have the same physical dimension. Visually, the identities on larger grids see... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model A rather popular model on the (infinite) square lattice with sites formula_93 is defined as follows: Begin with some nonnegative configuration of values formula_94 which is finite, meaning Any site formula_96 with is "unstable" and can "topple" (or "fire"), sending one of its chips to each of its... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model The order of the sandpile group is again the determinant of formula_61, which by the general version of the matrix tree theorem is the number of oriented spanning trees rooted at the sink. To better understand the structure of the sandpile group for different finite convex grids formula_2 of the ... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model Of specific interest is the question how the recurrent configurations dynamically change along the continuous geodesics of this torus passing through the identity. This question leads to the definition of the sandpile dynamics respectively induced by the integer-valued harmonic function formula_1... | https://en.wikipedia.org/wiki?curid=21409717 |
Abelian sandpile model A strongly related model is the so called divisible sandpile model, introduced by Levine and Peres in 2008, in which, instead of a discrete number of particles in each site formula_128, there is a real number formula_129 representing the amount of mass on the site. In case such mass is negative, ... | https://en.wikipedia.org/wiki?curid=21409717 |
Experiments in Fluids is a scientific, peer-reviewed scientific journal published monthly by Springer Science+Business Media. The journal presents contributions that employ existing experimental techniques to gain an understanding of the underlying flow physics in specific areas. These areas include turbulence, aerodyn... | https://en.wikipedia.org/wiki?curid=21420090 |
The Unscrambler X is a commercial software product for multivariate data analysis, used for calibration of multivariate data which is often in the application of analytical data such as near infrared spectroscopy and Raman spectroscopy, and development of predictive models for use in real-time spectroscopic analysis of... | https://en.wikipedia.org/wiki?curid=21420666 |
Association of Applied Geochemists The (AAG) is an international society that seeks to advance the study and application of geochemistry and represents scientists working in that field. The society was founded in 1970 as the Association of Exploration Geochemists. Members of the society are required to have worked in g... | https://en.wikipedia.org/wiki?curid=21421387 |
Association of Applied Geochemists The Society awards the AAG Gold Medal to recognize a lifetime's achievement in or outstanding contribution to applied geochemistry. It also offers an annual student paper prize to reward student contributors of outstanding papers on geochemistry. | https://en.wikipedia.org/wiki?curid=21421387 |
Limiting oxygen concentration The limiting oxygen concentration (LOC), also known as the minimum oxygen concentration (MOC), is defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. It is expressed in units of volume percent of oxygen. The LOC ... | https://en.wikipedia.org/wiki?curid=21421435 |
Bicarbonate indicator A hydrogencarbonate indicator (hydrogencarbonate indicator) is a type of pH indicator that is sensitive enough to show a color change as the concentration of carbon dioxide gas in an aqueous solution increases. The indicator is used in photosynthesis and respiration experiments to find out whether... | https://en.wikipedia.org/wiki?curid=21421469 |
John Krige () is an historian of science and technology and the Kranzberg Professor at the School of History, Technology and Society, Georgia Institute of Technology, Atlanta. Krige is originally a physical chemist by training, earning a PhD from the University of Pretoria in the subject. After earning a PhD in philoso... | https://en.wikipedia.org/wiki?curid=21422193 |
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