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HT-7, or Hefei Tokamak-7, is an experimental superconducting tokamak nuclear fusion reactor built in Hefei, China, to investigate the process of developing fusion power. The HT-7 was developed with the assistance of Russia, and was based on the earlier T-7 tokamak reactor. The reactor was built by the Hefei-based Insti... | {
"page_id": 3811299,
"title": "HT-7"
} |
In chemistry, the bicapped trigonal prismatic molecular geometry describes the shape of compounds where eight atoms or groups of atoms or ligands are arranged around a central atom defining the vertices of a biaugmented triangular prism. This shape has C2v symmetry and is one of the three common shapes for octacoordina... | {
"page_id": 58468325,
"title": "Bicapped trigonal prismatic molecular geometry"
} |
This is a list of notable Slovenian physicists. == A == Miroslav Adlešič == B == Robert Blinc (1933 - 2011) Silvo Breskvar (1902 - 1969) == C == Andrej Čadež - astrophysicist. Lavo Čermelj (1889 - 1980) == G == Peter Gosar (1923 - ) == K == Ignacij Klemenčič (1853 - 1901) Alojz Kodre (1944 - ) == P == Matjaž Perc (1979... | {
"page_id": 796647,
"title": "List of Slovenian physicists"
} |
Evo: The Last Gasp of the Dinosaurs is a German-style board game for three to five players, designed by Philippe Keyaerts and published by Eurogames. The game won the GAMES Magazine award for Game of the year 2002. It was nominated for the Origins Award for Best Graphic Presentation of a Board Game 2000. In 2004 it was... | {
"page_id": 1452008,
"title": "Evo (board game)"
} |
a six-sided die. Climate – a six-sided die is rolled to determine how the climate changes. Normally it proceeds in a cycle from hot to cold and back again, but on a 2 it stays the same, and on a 1 it moves in the opposite direction to the expected one. Movement and Combat – players can move their dinos. The more leg mu... | {
"page_id": 1452008,
"title": "Evo (board game)"
} |
a few turns later, so unlike many games where a winning player can come to dominate the game, the balance of power shifts frequently. Unlike most German-style board games, in the first edition it is possible for a player to be eliminated if all his dino tokens are removed from the board. But this is very rare in practi... | {
"page_id": 1452008,
"title": "Evo (board game)"
} |
kept most of the game intact it completely reworked the art away from the previous cartoonish style. Also some rule changes were introduced. For example players can now always bid on a new card. The designer said that these differences made for "different species from the start", the "new combat system makes Horns more... | {
"page_id": 1452008,
"title": "Evo (board game)"
} |
Endo agar (also called Endo's medium) is a microbiological growth medium with a faint pink colour. Originally developed for the isolation of Salmonella typhi, it is now used mostly as a coliform medium. Most gram-negative organisms grow well in this medium, while growth of gram-positive organisms is inhibited. Coliform... | {
"page_id": 22554602,
"title": "Endo agar"
} |
In the physical sciences, a partition coefficient (P) or distribution coefficient (D) is the ratio of concentrations of a compound in a mixture of two immiscible solvents at equilibrium. This ratio is therefore a comparison of the solubilities of the solute in these two liquids. The partition coefficient generally refe... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
each species is assigned its own Kow value. A related value, D, does not distinguish between different species, only indicating the concentration ratio of the substance between the two phases. == Nomenclature == Despite formal recommendation to the contrary, the term partition coefficient remains the predominantly used... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
the solute, which is electrically neutral, though this may not be true for the aqueous phase. To measure the partition coefficient of ionizable solutes, the pH of the aqueous phase is adjusted such that the predominant form of the compound in solution is the un-ionized, or its measurement at another pH of interest requ... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
on the pH of the aqueous phase, and log D = log P for non-ionizable compounds at any pH. For measurements of distribution coefficients, the pH of the aqueous phase is buffered to a specific value such that the pH is not significantly perturbed by the introduction of the compound. The value of each log D is then determi... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
solute) in the aqueous phase, and other variables are defined as previously. == Example partition coefficient data == The values for the octanol-water system in the following table are from the Dortmund Data Bank. They are sorted by the partition coefficient, smallest to largest (acetamide being hydrophilic, and 2,2',4... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
transcellular transport). For efficient transport, the drug must be hydrophobic enough to partition into the lipid bilayer, but not so hydrophobic, that once it is in the bilayer, it will not partition out again. Likewise, hydrophobicity plays a major role in determining where drugs are distributed within the body afte... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
tend to be more active. Hydrophobic agrochemicals in general have longer half-lives and therefore display increased risk of adverse environmental impact. === Metallurgy === In metallurgy, the partition coefficient is an important factor in determining how different impurities are distributed between molten and solidifi... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
chemical class to another—applying a regression equation derived from one chemical class to a second one—may not be reliable, since each chemical classes will have its characteristic regression parameters. === pH-metric === The pH-metric set of techniques determine lipophilicity pH profiles directly from a single acid-... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
the remainder for testing. QSAR equations, which in turn are based on calculated partition coefficients, can be used to provide toxicity estimates. Calculated partition coefficients are also widely used in drug discovery to optimize screening libraries and to predict druglikeness of designed drug candidates before they... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
its non-overlapping molecular fragments (defined as one or more atoms covalently bound to each other within the molecule). Fragmentary log P values have been determined in a statistical method analogous to the atomic methods (least-squares fitting to a training set). In addition, Hammett-type corrections are included t... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
K a ] , log D bases ≅ log P + log [ 1 1 + 10 p K a − p H ] . {\displaystyle {\begin{aligned}\log D_{\text{acids}}&\cong \log P+\log \left[{\frac {1}{1+10^{\mathrm {p} H-\mathrm {p} K_{a}}}}\right],\\\log D_{\text{bases}}&\cong \log P+\log \left[{\frac {1}{1+10^{\mathrm {p} K_{a}-\mathrm {pH} }}}\right].\end{align... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
than one if a substance is more soluble in fat-like solvents such as n-octanol, and less than one if it is more soluble in water. === Example values === Values for log Kow typically range between -3 (very hydrophilic) and +10 (extremely lipophilic/hydrophobic). The values listed here are sorted by the partition coeffic... | {
"page_id": 796652,
"title": "Partition coefficient"
} |
Tropospheric ozone depletion events are phenomena that reduce the concentration of ozone in the Earth's lower atmosphere. Ozone (O3) is a trace gas which has been of concern because of its unique dual role in different layers of the atmosphere. Apart from absorbing UV-B radiation and converting solar energy into heat i... | {
"page_id": 13248494,
"title": "Tropospheric ozone depletion events"
} |
enhance the speed of autocatalytic bromine release by confining the released bromine to a smaller space. Under these conditions, and with sufficient acidity, gaseous hypobromous acid (HOBr) can react with condensed sea salt bromide and produce bromine that is then released to the atmosphere. Subsequent photolysis of th... | {
"page_id": 13248494,
"title": "Tropospheric ozone depletion events"
} |
nitrogen oxide emissions. Increment in background levels of nitrogen oxide apparently strengthens the consumption of ozone and the enhancement of halogens. == See also == Arctic haze Free radical halogenation Tropospheric ozone Frost flower (sea ice) == References == | {
"page_id": 13248494,
"title": "Tropospheric ozone depletion events"
} |
Foster's rule, also known as the island rule or the island effect, is an ecogeographical rule in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment. For example, it is known that pygmy mammoths evolved from normal mammoths on small island... | {
"page_id": 1124336,
"title": "Foster's rule"
} |
could also cause the body mass differences between mainland and island populations. == References == == External links == "Why Do Islands Breed Giants (And Sometimes Dwarfs)?", episode of PBS's Nova | {
"page_id": 1124336,
"title": "Foster's rule"
} |
The Biomolecule Stretching Database contains information about the mechanostability of proteins based on their resistance to stretching. == References == == External links == Official website | {
"page_id": 30353393,
"title": "Biomolecule Stretching Database"
} |
Teresa Kowalska (July 19, 1946 – 2023) was a Polish chemist, specialized in the theory and application of chromatography. She was a professor emeritus of University of Silesia in Katowice. == Education == Kowalska received a master's degree in chemistry in 1968 and a PhD in physical chemistry in 1972, both from Higher ... | {
"page_id": 75638769,
"title": "Teresa Kowalska"
} |
The exome is composed of all of the exons within the genome, the sequences which, when transcribed, remain within the mature RNA after introns are removed by RNA splicing. This includes untranslated regions of messenger RNA (mRNA), and coding regions. Exome sequencing has proven to be an efficient method of determining... | {
"page_id": 22095859,
"title": "Exome"
} |
months. Next-gen sequencing includes both whole-exome sequencing and whole-genome sequencing. === Whole-exome sequencing === Sequencing an individual's exome instead of their entire genome has been proposed to be a more cost-effective and efficient way to diagnose rare genetic disorders. It has also been found to be mo... | {
"page_id": 22095859,
"title": "Exome"
} |
creating the potential for stigmas or negative attitudes towards that group as a result. == Diseases and diagnoses == Rare mutations that affect the function of essential proteins constitute the majority of Mendelian diseases. In addition, the overwhelming majority of disease-causing mutations in Mendelian loci can be ... | {
"page_id": 22095859,
"title": "Exome"
} |
of exome sequencing in the context of disease diagnosis has been on protein coding "loss of function" alleles. Research has shown, however, that future advances that allow the study of non-coding regions, within and without the exome, may lead to additional abilities in the diagnoses of rare Mendelian disorders. The ex... | {
"page_id": 22095859,
"title": "Exome"
} |
In scattering theory, a scattering channel is a quantum state of the colliding system before or after the collision ( t → ± ∞ {\displaystyle t\to \pm \infty } ). The Hilbert space spanned by the states before collision (in states) is equal to the space spanned by the states after collision (out states) which are both F... | {
"page_id": 2172915,
"title": "Scattering channel"
} |
A Miyake event is an observed sharp enhancement of the production of cosmogenic isotopes by cosmic rays. It can be marked by a spike in the concentration of radioactive carbon isotope 14C in tree rings, as well as 10Be and 36Cl in ice cores, which are all independently dated. At present, five significant events are kno... | {
"page_id": 72230901,
"title": "Miyake event"
} |
% higher, because of the combined effect of the lower atmospheric CO2 level and weaker geomagnetic field However, the event has not yet been independently confirmed in wood from other regions, nor it is reliably supported by a clear corresponding spike in other isotopes, such as beryllium-10, that are needed to reconst... | {
"page_id": 72230901,
"title": "Miyake event"
} |
performed on the tree-rings of wooden building remains from the Neolithic waterlogged site of Dispilio in north-western Greece, identified the Miyake event of 5259 BC, thus for a first time absolutely dating a Neolithic site in Europe from the 6th millennium BC to a single calendar year. == See also == Carrington Event... | {
"page_id": 72230901,
"title": "Miyake event"
} |
Flow focusing in fluid dynamics is a technology whose aim is the production of drops or bubbles by straightforward hydrodynamic means. The output is a dispersed liquid or gas, frequently in the form of a fine aerosol or an emulsion. No other driving force is required, apart from traditional pumping, a key difference wi... | {
"page_id": 28321786,
"title": "Flow focusing"
} |
much smaller than the exit orifice, thus precluding any contact (which may lead to unwanted deposition or reaction). Capillary instability breaks up the steady jet into homogeneous droplets or bubbles. The feed tube may be composed of two or more concentric needles and different immiscible liquids or gases to be inject... | {
"page_id": 28321786,
"title": "Flow focusing"
} |
as Gas Dynamic Virtual Nozzle (GDVN) since its adoption in the development of SFX. Flow focusing may be also applied in the food, medicine, pharmaceutical, cosmetic, photographic and environmental industry, among other potential uses. The production of compound particles and microcapsules is an important field: drug en... | {
"page_id": 28321786,
"title": "Flow focusing"
} |
Poly-γ-glutamate is a metabolite of Bacillus subtilis. Poly-γ-glutamate inhibits tyrosinase and melanogenesis in vitro. == References == | {
"page_id": 41101311,
"title": "Poly-γ-glutamate"
} |
Henry A. Bent (December 21, 1926 – January 3, 2015) was a professor of physical chemistry who studied molecular orbitals to develop atomic hybridization and valence bond theories. Bent's rule, which predicts the orbital hybridization of a central atom as a function of the electronegativities of the substituents attache... | {
"page_id": 63514630,
"title": "Henry A. Bent"
} |
Teijin Limited (帝人株式会社, Teijin Kabushiki-gaisha) is a Japanese chemical, pharmaceutical and information technology company. Its main fields of operation are high-performance fibers such as aramid, carbon fibers & composites, healthcare, films, resin & plastic processing, polyester fibers, products converting and IT pro... | {
"page_id": 2369543,
"title": "Teijin"
} |
The British Crystallographic Association (BCA) is an association for crystallographers, based in the United Kingdom. It is one of the largest crystallographic societies in the world. The Association administers a Dorothy Hodgkin Prize and an Arnold Beevers Bursary Fund. == See also == American Crystallographic Associat... | {
"page_id": 42346503,
"title": "British Crystallographic Association"
} |
The root alk- is used in organic chemistry to form classification names for classes of organic compounds which contain a carbon skeleton but no aromatic rings. It was extracted from the word alcohol by removing the -ol suffix. See e.g. alkyl, alkane. The International Union of Pure and Applied Chemistry (IUPAC) nomencl... | {
"page_id": 3680262,
"title": "Alk-"
} |
to indicate that the carbon chain is cyclic (ring-shaped). Other infixes: There are a few other infixes used in IUPAC nomenclature to indicate more complex structures, such as "spiro-" and "bicyclo-". == References == | {
"page_id": 3680262,
"title": "Alk-"
} |
Nutrient agar is a general-purpose solid medium supporting growth of a wide range of non-fastidious organisms. It typically contains (mass/volume): 0.5% peptone – this provides organic nitrogen 0.3% beef extract/yeast extract – the water-soluble content of these contribute vitamins, carbohydrates, nitrogen, and salts 1... | {
"page_id": 19146762,
"title": "Nutrient agar"
} |
Artur Lind (6 April 1927, Vändra – 30 November 1989, Tartu) was an Estonian biologist and is considered to be the founder of molecular biology in Estonia. Lind studied to be a surgeon at the University of Tartu. Due to an allergic reaction to analgesics used at the time, he was unable to continue working as a surgeon a... | {
"page_id": 61024270,
"title": "Artur Lind"
} |
The molecular formula C24H36O3 may refer to: Anagestone acetate Nabilone Nandrolone caproate Testosterone isovalerate Testosterone valerate | {
"page_id": 40183822,
"title": "C24H36O3"
} |
Mitochondria-associated membranes (MAMs) represent regions of the endoplasmic reticulum (ER) which are reversibly tethered to mitochondria. These membranes are involved in import of certain lipids from the ER to mitochondria and in regulation of calcium homeostasis, mitochondrial function, autophagy and apoptosis. They... | {
"page_id": 52832272,
"title": "Mitochondria associated membranes"
} |
to form auto-phagosomes. These closed membranes are double membrane-bond, with lysosomes inside it. The main function of these membrane is degradation, as role in cellular homeostasis. However, the origin of them has remained unclear. Maybe it is the plasma membrane, the endoplasmic reticulum (ER) and the mitochondria.... | {
"page_id": 52832272,
"title": "Mitochondria associated membranes"
} |
disease have been reported to have an up-regulation of lipids synthesized in the MAMs juxtaposition and an up regulation of protein complexes present in the contact region between the ER and mitochondria. Research has suggested that the sites of MAM are the primary sites of activity for γ-secretase activity and amyloid... | {
"page_id": 52832272,
"title": "Mitochondria associated membranes"
} |
rendered nonfunctional in a process known as mitophagy. However, mutations in the Parkin and pink1 genes have been associated with the cells becoming incapable of degrading faulty mitochondria. The proteins alpha-Synuclein (α-Syn) and DJ-1 have been shown to promote MAM function interaction between the ER and the mitoc... | {
"page_id": 52832272,
"title": "Mitochondria associated membranes"
} |
The molecular formula C24H40N5O8 (molar mass: 526.603 g/mol, exact mass: 526.2877 u) may refer to: Desmosine Isodesmosine | {
"page_id": 37693457,
"title": "C24H40N5O8"
} |
The Leuckart thiophenol reaction is the decomposition of a diazoxanthate, by gentle warming in a slightly acidic cuprous medium, to its corresponding aryl xanthates which give aryl thiols on alkaline hydrolysis and aryl thioethers on further warming. This reaction was first reported by Rudolf Leuckart in 1890. == Refer... | {
"page_id": 25896981,
"title": "Leuckart thiophenol reaction"
} |
Genetic Algorithm for Rule Set Production (GARP) is a computer program based on genetic algorithm that creates ecological niche models for species. The generated models describe environmental conditions (precipitation, temperatures, elevation, etc.) under which the species should be able to maintain populations. As inp... | {
"page_id": 12986391,
"title": "Genetic Algorithm for Rule Set Production"
} |
Ong Kok Hai (born 1945 in Penang) is a Malaysian microbiologist and Professor of Microbiology at the International Medical University. He was one of the founders of the International Medical University in 1992 and also played a major role in the establishment of the medical schools at the University of Science, Malaysi... | {
"page_id": 50145306,
"title": "Ong Kok Hai"
} |
The Rainbow Bridge is the theme of several works written first in 1959, then in the 1980s and 1990s, that speak of an other-worldly place where pets go upon death, eventually to be reunited with their owners. One is a short story by Edna Clyne-Rekhy. The other is a six-stanza poem of rhyming pentameter couplets, create... | {
"page_id": 1583130,
"title": "Rainbow Bridge (pets)"
} |
side by side, they cross the Rainbow Bridge together into Heaven, to play again and be together in love and happiness, never again to be separated. == Authorship == In February 2023, authorship of the original story was confirmed by National Geographic magazine as Edna Clyne-Rekhy, an 82-year-old artist from Scotland. ... | {
"page_id": 1583130,
"title": "Rainbow Bridge (pets)"
} |
exploding $69 billion pet care industry." == Background == The concept of a paradise where pets wait for their human owners appeared much earlier, in the little-known sequel to Beautiful Joe, Margaret Marshall Saunders' book Beautiful Joe's Paradise. In this green land, the animals do not simply await their owners, but... | {
"page_id": 1583130,
"title": "Rainbow Bridge (pets)"
} |
Artificial development, also known as artificial embryogeny or machine intelligence or computational development, is an area of computer science and engineering concerned with computational models motivated by genotype–phenotype mappings in biological systems. Artificial development is often considered a sub-field of e... | {
"page_id": 16132124,
"title": "Artificial development"
} |
multi-agent systems in dynamic environments. Parallel Problem Solving from Nature (PPSN) XI, Kraków, Poland. (https://www.researchgate.net/profile/James_Whitacre/publication/220701596_The_Role_of_Degenerate_Robustness_in_the_Evolvability_of_Multi-agent_Systems_in_Dynamic_Environments/links/0d2b2c6889b5121d730dd3be.pdf)... | {
"page_id": 16132124,
"title": "Artificial development"
} |
Embryo drawing is the illustration of embryos in their developmental sequence. In plants and animals, an embryo develops from a zygote, the single cell that results when an egg and sperm fuse during fertilization. In animals, the zygote divides repeatedly to form a ball of cells, which then forms a set of tissue layers... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
as evidence of von Baer's laws. The series of twenty-four embryos from the early editions of Haeckel's Anthropogenie remain the most famous. The different species are arranged in columns, and the different stages in rows. Similarities can be seen along the first two rows; the appearance of specialized characters in eac... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
the result of certain adaptations to embryonic life due to environmental changes. In his drawings, Haeckel cites the notochord, pharyngeal arches and clefts, pronephros and neural tube as palingenetic features. However, the yolk sac, extra-embryonic membranes, egg membranes and endocardial tube are considered caenogene... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
animals, and there is never a complete morphological similarity between an embryo and a lower adult. Von Baer's embryo drawings display that individual development proceeds from general features of the developing embryo in early stages through differentiation into special features specific to the species, establishing ... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
embryological development strongly differs from Haeckel's depiction, for His argues that the phylogenetic explanation of ontogenetic events is unnecessary. His argues that all ontogenetic events are the "mechanical" result of differential cell growth. His' embryology is not explained in terms of ancestral history. The ... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
caused much controversy among Intelligent Design proponents recently and Haeckel's intellectual opponents in the past. Although the early embryos of different species exhibit similarities, Haeckel apparently exaggerated these similarities in support of his Recapitulation theory, sometimes known as the Biogenetic Law or... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
anti-materialist view of nature. Rutimeyer claimed that Haeckel "had taken to kinds of liberty with established truth". Rutimeyer claimed that Haeckel presented the same image three consecutive times as the embryo of the dog, the chicken, and the turtle. Theodor Bischoff (1807–1882), was a strong opponent of Darwinism.... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
in discussions of the history of embryology, with clarification that these are no longer considered valid. == Haeckel's proponents (past and present) == Although Charles Darwin accepted Haeckel's support for natural selection, he was tentative in using Haeckel's ideas in his writings; with regard to embryology, Darwin ... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
the systematic comparison of the folklore, beliefs and practices of different societies. Müller's work relies specifically on theoretical assumptions that are very similar to Haeckel's and reflects the German practice to maintain strong connections between empirical research and the philosophical framework of science. ... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
drawings should not be considered falsifications of any sort. Although modern defense of Haeckel's embryo drawings still considers the inaccuracy of his drawings, charges of fraud are considered unreasonable. As Erland Nordenskiöld argues, charges of fraud against Haeckel are unnecessary. R. Bender ultimately goes so f... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
of the History of Medicine. 74 (1): 29–71. doi:10.1353/bhm.2000.0020. PMID 10740908. S2CID 40294481. Judson, Horace Freeland (2004). The Great Betrayal: Fraud in Science. Orlando, Florida: Harcourt, Inc. ISBN 978-0-15-100877-3. Nordenskiold, Erik (1928). The History of Biology: A Survey. New York, New York: Tudor Publi... | {
"page_id": 10273,
"title": "Embryo drawing"
} |
Aminoethanol may refer to: 1-Aminoethanol Ethanolamine (2-aminoethanol, ETA, or MEA) | {
"page_id": 58009634,
"title": "Aminoethanol"
} |
An electrotroph is a microorganism which can receive electrons necessary for its growth from an electrode (power supply) terminal or other electron donors. The chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans, that lives in ocean thermal vents, has been shown to exhibit electrotrophic behavior in experime... | {
"page_id": 29173795,
"title": "Electrotroph"
} |
Enthalpy ( ) is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant external pressure, which is conveniently provided by the large ambient atmosphere... | {
"page_id": 10274,
"title": "Enthalpy"
} |
change equals the energy exchanged with the environment by heat. In chemistry, the standard enthalpy of reaction is the enthalpy change when reactants in their standard states (p = 1 bar; usually T = 298 K) change to products in their standard states. This quantity is the standard heat of reaction at constant pressure ... | {
"page_id": 10274,
"title": "Enthalpy"
} |
the size of the system (for homogeneous systems). As intensive properties, the specific enthalpy h = H/m is referenced to a unit of mass m of the system, and the molar enthalpy Hm = H/n, where n is the number of moles. For inhomogeneous systems the enthalpy is the sum of the enthalpies of the component subsystems: H = ... | {
"page_id": 10274,
"title": "Enthalpy"
} |
to the system, δW is a small amount of work performed by the system. In a homogeneous system in which only reversible processes or pure heat transfer are considered, the second law of thermodynamics gives δQ = T dS, with T the absolute temperature and dS the infinitesimal change in entropy S of the system. Furthermore,... | {
"page_id": 10274,
"title": "Enthalpy"
} |
{1}{V}}\left({\frac {\partial V}{\partial T}}\right)_{p}.} With this expression one can, in principle, determine the enthalpy if Cp and V are known as functions of p and T. However the expression is more complicated than d H = T d S + V d p {\displaystyle \mathrm {d} H=T\,\mathrm {d} S+V\,\mathrm {d} p} because T is no... | {
"page_id": 10274,
"title": "Enthalpy"
} |
S[p], p, and {Ni} are said to be the natural state variables in this representation. They are suitable for describing processes in which they are determined by factors in the surroundings. For example, when a virtual parcel of atmospheric air moves to a different altitude, the pressure surrounding it changes, and the p... | {
"page_id": 10274,
"title": "Enthalpy"
} |
the internal properties of a constant-volume system and therefore the internal energy is used. In chemistry, experiments are often conducted at constant atmospheric pressure, and the pressure–volume work represents a small, well-defined energy exchange with the atmosphere, so that ΔH is the appropriate expression for t... | {
"page_id": 10274,
"title": "Enthalpy"
} |
H=\delta Q.} This is why the now-obsolete term heat content was used for enthalpy in the 19th century. == Applications == In thermodynamics, one can calculate enthalpy by determining the requirements for creating a system from "nothingness"; the mechanical work required, pV, differs based upon the conditions that obtai... | {
"page_id": 10274,
"title": "Enthalpy"
} |
and equals the heat released in the reaction if no electrical or mechanical work is done. In other words, the overall decrease in enthalpy is achieved by the generation of heat. Conversely, for a constant-pressure endothermic reaction, ΔH is positive and equal to the heat absorbed in the reaction. From the definition o... | {
"page_id": 10274,
"title": "Enthalpy"
} |
of that for the forward process. A common standard enthalpy change is the enthalpy of formation, which has been determined for a large number of substances. Enthalpy changes are routinely measured and compiled in chemical and physical reference works, such as the CRC Handbook of Chemistry and Physics. The following is ... | {
"page_id": 10274,
"title": "Enthalpy"
} |
as the enthalpy change required to separate one mole of a substance into its constituent atoms completely. Enthalpy of neutralization is defined as the enthalpy change observed in a constituent of a thermodynamic system when one mole of water is formed when an acid and a base react. Standard enthalpy of solution is def... | {
"page_id": 10274,
"title": "Enthalpy"
} |
to the system by mass flowing in and by heating, minus the amount lost by mass flowing out and in the form of work done by the system: d U = δ Q + d U in − d U out − δ W , {\displaystyle \mathrm {d} U=\delta Q+\mathrm {d} U_{\text{in}}-\mathrm {d} U_{\text{out}}-\delta W,} where Uin is the average internal energy enter... | {
"page_id": 10274,
"title": "Enthalpy"
} |
{d} U_{\text{cv}}=\delta Q+\mathrm {d} U_{\text{in}}+\mathrm {d} (p_{\text{in}}V_{\text{in}})-\mathrm {d} U_{\text{out}}-\mathrm {d} (p_{\text{out}}V_{\text{out}})-\delta W_{\text{shaft}}.} The definition of enthalpy H permits us to use this thermodynamic potential to account for both internal energy and pV work in flu... | {
"page_id": 10274,
"title": "Enthalpy"
} |
conserved between system inlet and outlet. Otherwise, it has to be included in the enthalpy balance. During steady-state operation of a device (see Turbine, Pump, and Engine), the average dU/dt may be set equal to zero. This yields a useful expression for the average power generation for these devices in the absence of... | {
"page_id": 10274,
"title": "Enthalpy"
} |
so-called throttling process, also known as Joule–Thomson expansion. It concerns a steady adiabatic flow of a fluid through a flow resistance (valve, porous plug, or any other type of flow resistance) as shown in the figure. This process is very important, since it is at the heart of domestic refrigerators, where it is... | {
"page_id": 10274,
"title": "Enthalpy"
} |
kJ /kg . It corresponds roughly with p = 13 bar and T = 108 K . Throttling from this point to a pressure of 1 bar ends in the two-phase region (point f). This means that a mixture of gas and liquid leaves the throttling valve. Since the enthalpy is an extensive parameter, the enthalpy in f ( hf ) is equal to the entha... | {
"page_id": 10274,
"title": "Enthalpy"
} |
m ˙ h 1 − m ˙ h 2 + P . {\displaystyle 0=-{\dot {Q}}+{\dot {m}}\,h_{1}-{\dot {m}}\,h_{2}+P~.} The minimal power needed for the compression is realized if the compression is reversible. In that case the second law of thermodynamics for open systems gives 0 = − Q ˙ T a + m ˙ s 1 − m ˙ s 2 . {\displaystyle 0=-{\frac {\,{\... | {
"page_id": 10274,
"title": "Enthalpy"
} |
idea of capacity to perform work. Entropy uses the Greek word τροπή (tropē) meaning transformation or turning. Enthalpy uses the root of the Greek word θάλπος (thalpos) "warmth, heat". The term expresses the obsolete concept of heat content, as dH refers to the amount of heat gained in a process at constant pressure on... | {
"page_id": 10274,
"title": "Enthalpy"
} |
In quantum optics, a superradiant phase transition is a phase transition that occurs in a collection of fluorescent emitters (such as atoms), between a state containing few electromagnetic excitations (as in the electromagnetic vacuum) and a superradiant state with many electromagnetic excitations trapped inside the em... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
potential, and will undergo ferroelectric-like phase transition. In this model, the system is mathematically equivalent for one mode of excitation to the Trojan wave packet, when the circularly polarized field intensity corresponds to the electromagnetic coupling constant. Above the critical value, it changes to the un... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
quantum mechanics including the electromagnetic field the generalized Bohr–van Leeuwen theorem does not work and the electromagnetic interactions cannot be eliminated while they only change the p ⋅ A {\displaystyle \mathbf {p} \cdot \mathbf {A} } vector potential coupling to the electric field x ⋅ E {\displaystyle \mat... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
( a ^ b ^ † + a ^ † b ^ + a ^ b ^ + a ^ † b ^ † ) , {\displaystyle {\hat {H}}_{\text{JC}}=\hbar \omega {\hat {a}}^{\dagger }{\hat {a}}+\hbar \omega {\hat {b}}^{\dagger }{\hat {b}}+{\frac {\hbar \Omega }{2}}\left({\hat {a}}{\hat {b}}^{\dagger }+{\hat {a}}^{\dagger }{\hat {b}}+{\hat {a}}{\hat {b}}+{\hat {a}}^{\dagger }{\... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
{\displaystyle {\hat {H}}_{\text{JC}}=\hbar \omega {\hat {a}}^{\dagger }{\hat {a}}+\hbar \omega {\frac {{\hat {\sigma }}_{z}}{2}}+{\frac {\hbar \Omega }{2}}\left({\hat {a}}{\hat {\sigma }}_{+}+{\hat {a}}^{\dagger }{\hat {\sigma }}_{-}\right),} and the energies for the case of zero detuning are E ± ( n ) = ℏ ω ( n + 1 2... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
field-atom coupling is significantly stronger than the energy difference between the atom levels. When the condition is fulfilled, the equation gives the solution for the order parameter n {\displaystyle n} depending on the inverse of the temperature 1 / β {\displaystyle 1/\beta } , which means non-vanishing ordered fi... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
a 3 < 0 {\displaystyle {\frac {m\omega ^{2}}{2}}-{\frac {1}{2}}\times 4\times {\frac {e^{2}}{4\pi \epsilon _{0}}}{\frac {1}{a^{3}}}<0} or e 2 π ϵ 0 m ω 2 1 a 3 > 1 {\displaystyle {\frac {e^{2}}{\pi \epsilon _{0}m\omega ^{2}}}{\frac {1}{a^{3}}}>1} Making it artificially quantum by multiplying the numerator and the denom... | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
so called electron gas plasma frequency. == References == == External links == Old Warsaw School of "No-Go" of the Superradiant Phase Transition, the talk by the 2022 Wigner Medal recipient Iwo Bialynicki-Birula's former PhD student K. Rzążewski | {
"page_id": 39462950,
"title": "Superradiant phase transition"
} |
Yaakov (Yasha) Rosenfeld (Hebrew: יעקב (יאשה) רוזנפלד; February 16, 1948 – July 21, 2002) was a condensed-matter theorist who made outstanding contributions to the statistical mechanics of liquids and dense plasmas. He was a leading figure in theories of liquids and his fundamental measure approach to classical density... | {
"page_id": 3614758,
"title": "Yasha Rosenfeld"
} |
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