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Compounds of fluorine However, if a molecule was synthesized, it would have to go through a high-energy transitional state, from which it could decay into two molecules. But since the transitional state is higher in energy than the hexatomic molecule, the energy difference would need to be added to reach the transition... | https://en.wikipedia.org/wiki?curid=39292926 |
Compounds of fluorine Direct fluorination becomes even less important when it comes to organohalogens or unsaturated compounds reactions, or when a prefluorocarbon is desired (then HF-based electrolysis is typically used). In contrast, the fluoropolymers are formed by polymerizing free radicals; other techniques used f... | https://en.wikipedia.org/wiki?curid=39292926 |
Compounds of fluorine In general, the boiling points are even more elevated by combination of halogen atoms because the varying size and charge of different halogens allows more intermolecular attractions. As with fluorocarbons, chlorofluorocarbons and bromofluorocarbons are not flammable: they do not have carbon–hydro... | https://en.wikipedia.org/wiki?curid=39292926 |
Compounds of fluorine They share most of perfluorocarbon properties (inertness, stability, non-wettingness and insolubility in water and oils, slipperiness, etc.), but may differ because of the functional group properties, although the perfluorocarbon tail differ the group-specific properties as compared to those of hy... | https://en.wikipedia.org/wiki?curid=39292926 |
Compounds of fluorine Each fluoropolymer has own characteristic properties, though. The simplest fluoroplastic is polytetrafluoroethylene (PTFE, DuPont brand Teflon), which is a simple linear chain polymer with the repeating structural unit:–CF–. PTFE has a backbone of carbons single bonded in a long chain, with all si... | https://en.wikipedia.org/wiki?curid=39292926 |
Compounds of fluorine It differs from PTFE by having a quarter of fluorine replaced with chlorines, yet this difference brings even greater hardness, creep resistance, and moisture persistence. Mild fluorination of polyethylene gives does not make all of the plastic lose its hydrogens for fluorine; only a thin layer (0... | https://en.wikipedia.org/wiki?curid=39292926 |
Compounds of fluorine There are three main families of fluoroelasters. VDF/HFP is a copolymer system of vinylidene fluoride and (at least 20%) hexafluoropropylene. TFE/propylene is another copylymer system with better chemical resistance to some solvents. TFE/PMVE (perfluoromethylvinyl ether) is a copolymer system whic... | https://en.wikipedia.org/wiki?curid=39292926 |
Lely method The or Lely process is a crystal growth technology used for producing silicon carbide crystals for the semi-conductor industry. The patent for this process was filed in the Netherlands in 1954 and in the United States in 1955 by Jan Anthony Lely of Philips Electronics. The patent was subsequently granted on... | https://en.wikipedia.org/wiki?curid=39295868 |
Edwards equation The in organic chemistry is a two-parameter equation for correlating nucleophilic reactivity, as defined by relative rate constants, with the basicity of the nucleophile (relative to protons) and its polarizability. This equation was first developed by John O. Edwards in 1954 and later revised based on... | https://en.wikipedia.org/wiki?curid=39302352 |
Edwards equation Swain and Scott later tried to define a more specific and quantitative relationship by correlating nucleophilic data with a single-parameter equation derived in 1953: This equation relates the rate constant "k", of a reaction, normalized to that of a standard reaction with water as the nucleophile ("k"... | https://en.wikipedia.org/wiki?curid=39302352 |
Edwards equation It is related to the oxidation potential (E) of the reaction formula_5 (oxidative dimerization of the nucleophile) by the equation: where 2.60 is the correction for the oxidative dimerization of water, obtained from a least-squares correlation of data in Edwards’ first paper on the subject. α and β are... | https://en.wikipedia.org/wiki?curid=39302352 |
Edwards equation A later paper by Edwards and Pearson, following research done by Jencks and Carriuolo in 1960 led to the discovery of an additional factor in nucleophilic reactivity, which Edwards and Pearson called the alpha effect, where nucleophiles with a lone pair of electrons on an atom adjacent to the nucleophi... | https://en.wikipedia.org/wiki?curid=39302352 |
Nanofluids in solar collectors Nanofluid-based direct solar collectors are solar thermal collectors where nanoparticles in a liquid medium can scatter and absorb solar radiation. They have recently received interest to efficiently distribute solar energy. Nanofluid-based solar collector have the potential to harness so... | https://en.wikipedia.org/wiki?curid=39313159 |
Nanofluids in solar collectors Dispersing trace amounts of nanoparticles into common base fluids has a significant impact on the optical as well as thermo physical properties of base fluid. This characteristic can be used to effectively capture and transport solar radiation. Enhancement of the solar irradiance absorpti... | https://en.wikipedia.org/wiki?curid=39313159 |
Nanofluids in solar collectors So, addition of solid particles in a fluid can increase the conductivity of liquids .But we cannot add large solid particles due to main problems: Due to these drawbacks, usage of solid particles have not become practically feasible. Recent improvements in nanotechnology made it possible ... | https://en.wikipedia.org/wiki?curid=39313159 |
Nanofluids in solar collectors Since, heat can be transferred rapidly within the such clusters, the volume fraction of the highly conductive phase is larger than the volume of solid, thus increasing its thermal conductivity In the last ten years, many experiments have been conducted numerically and analytically to vali... | https://en.wikipedia.org/wiki?curid=39313159 |
Gerhard Schmidt (crystallographer) Gerhard Martin Julius Schmidt (born, 21 August 1919 in Berlin – died July 12, 1971 in Zurich, buried in Rehovot), organic chemist and chemical crystallographer, director of the Weizmann Institute of Science in the late 1950s and again in the late 1960s. Schmidt was the founder of X-ra... | https://en.wikipedia.org/wiki?curid=39313294 |
Gerhard Schmidt (crystallographer) Being an emigrant from Germany, he was deported in July 1940, together with 200 other “enemy aliens,” to a detention camp in Australia. In August 1941, he was finally cleared and returned to England. Later in life, Schmidt liked to date some of his most original ideas in chemistry to ... | https://en.wikipedia.org/wiki?curid=39313294 |
Gerhard Schmidt (crystallographer) Schmidt devoted considerable time to applied science. From 1960 to 1964, he chaired the Board of Yeda Research & Development Co., the Weizmann Institute's technology transfer arm. Outside the Weizmann Institute, Schmidt was actively involved in Israel's scientific and technological de... | https://en.wikipedia.org/wiki?curid=39313294 |
Gerhard Schmidt (crystallographer) At the Weizmann Institute, the work of his group centered around the development of X-ray crystallographic methods for the determination of molecular structures in order to understand the properties and reactivity of organic solids. In the early 1950s, Schmidt investigated the structu... | https://en.wikipedia.org/wiki?curid=39313294 |
Gerhard Schmidt (crystallographer) Gerhard Schmidt (1919-1971) and the Road to Chemical Crystallography. In: "Solid State Photochemistry. A Collection of Papers by G. M. J. Schmidt and his Collaborators Describing a Symbiotic Relationship between X-Ray Crystallography and Synthetic Organic Photochemistry. Herausgegeben... | https://en.wikipedia.org/wiki?curid=39313294 |
Gold glass or gold sandwich glass is a luxury form of glass where a decorative design in gold leaf is fused between two layers of glass. First found in Hellenistic Greece, it is especially characteristic of the Roman glass of the Late Empire in the 3rd and 4th century AD, where the gold decorated roundels of cups and o... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass Both of these processes were also used in ancient times, and the German and French languages often use their native terms for what is called "gold glass" in English. Gold ruby glass or "cranberry glass" is actually red, coloured by the addition of gold oxide. Gold-band glass is another ancient technique cove... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass Some of the finer later medallions seem to have been made as such from the start, and some contain pigments other than the gold. These smoother-edged medallions exploited the medium of glass as a matrix for portrait miniatures, and it has proved to be a very effective one, outlasting all alternatives except ... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass In the 11th century the relatively new Christian centre of Kiev seems to have used gold tesserae made in Constantinople. Roman gold glass beads were made by using an inner tube or rod to which the gold leaf was stuck. A larger tube was slid over that and the beads crimped off. Easily transported and very att... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass A mosaic in the North African ruins of Dougga shows two hefty slaves pouring wine from "amphorae" into two shallow bowls held by slaves waiting on the banquet. The two "amphorae" are inscribed with "ΠΙΕ" and "ΣΗϹΗϹ" the Greek originals of the toasting formulae "pie zeses" ("Drink, may you live", discussed be... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass The very untidy trimming of many examples may be explained by this; an example in the Metropolitan Museum of Art is still attached to a chunk of mortar round much of its edge, showing that the mortar overlapped the edge of the glass. Rough edges would mostly have been hidden by the mortar and also provided a... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass 4 cm high, one of two from a tomb in Canosa in Apulia dating to around 270–160 BC. It has most of the interior very finely decorated with lotus and acanthus motifs, which are more typical of gold glass in this period than designs with human figures. There are a handful of other near complete examples, and ra... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass The decorated late Roman pieces are usually assumed to have been made in and around Rome, especially in the case of portraits of residents there, but also in the Rhineland around Cologne and Augusta Treverorum, modern Trier, which was a centre for other luxury glass products like cage cups. Alexandria is sti... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass One of the most famous Alexandrian-style portrait medallions, with an inscription in Egyptian Greek, was later mounted in an Early Medieval crux gemmata in Brescia, in the mistaken belief that it showed the pious empress and Gothic queen Galla Placida (died 450) and her children; in fact the knot in the cent... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass An "Alexander plate with hunting scene" in the Cleveland Museum of Art is, if genuine, a very rare example of a complete vessel decorated with gold glass, and comes from the upper elite of Roman society. It is a shallow bowl or plate 25.7 cm (10 1/8 inches) in diameter and 4.5 cm (1 3/4 inches) high. The dec... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass Such secular "blessings" are typical, and on roundels made from cups they often urge the owner to drink, even when the iconography is religious. One Jewish example has the usual array of symbols and the inscription "Drink, [so] you may live, Elares". The Wedding at Cana is a popular Christian subject, with o... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass The portraits of the sons of Constantine I allow an unusually precise probable dating to 326, his "vicennalia", or the 25th anniversary of his reign. Another complete piece is a paten from the Basilica of St. Severin, Cologne, founded in the 4th century. This is decorated with roundels containing Old Testame... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass Most glasses feature a single image occupying most of the round space within the border, but some have a number of small scenes, usually arranged in small circular frames around a central image. Most portraits are between bust and half-length. The small number of glasses with Jewish iconography are covered s... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass Christ is shown in a number of examples, usually as clean-shaven and youthful, as well as figures such as the Good Shepherd which may symbolize him, or in some cases Orpheus or general bucolic imagery. A small Christ may stand between the heads of a married couple, blessing them. Orants perhaps representing ... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass Two identical glasses featuring two boxers with a trainer, all named, suggest that the glasses may sometimes have been ordered in sets; one may speculate that this may have been common. Single examples show Athena presiding over shipbuilders, a pair of personifications of Rome and Constantinople, and female ... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass One glass in the British Museum is unusual in a number of respects: between a named couple is a smaller figure of Hercules, and the inscription: "ORFITVS ET CONSTANTIA IN NOMINE HERCVLlS ACERENTINO FELICES BIBATIS" or "Orfitus and Constantia, may you live/drink in happiness in the name of Hercules of Acerent... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass The most common arrangement is on two levels, with two Lions of Judah flanking a Torah ark above, and below two menarot, a shofar (rams horn), etrog, lulav and perhaps others of the four Species, scrolls and vases. Not all the tiny symbols can be confidently identified. Alternatively, the objects are all in ... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass They would seem to have been given as gifts on the same sort of occasions, and there is evidence that Roman Jews shared the general Roman custom of New Year present-giving. The technique continued to be used for mosaic tesserae, and at times for pieces that remained relatively large, for example in a small t... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass The first significant publication on them was by Filippo Buonarroti in 1716, "Osservazioni sopra alcuni frammenti di vasi antichi di vetro ornate di figure trovati nei cimiteri di Roma" ("Observations on some fragments of antique glass vases decorated with figures, found in the cemeteries of Rome"), in which... | https://en.wikipedia.org/wiki?curid=39320626 |
Gold glass The most recent of many catalogues since the 18th century are by C.R. Morey in 1959, with 460 Roman vessel bases, against 426 in S. Smith's thesis of 2000. The corpus continues to be expanded by occasional new finds. | https://en.wikipedia.org/wiki?curid=39320626 |
Dihydroxyflavone may refer to: | https://en.wikipedia.org/wiki?curid=39335837 |
Dualin is an explosive material based on nitroglycerin and nitrogenized cellulose using sawdust or wood pulp. is inferior to dynamite and more liable to explosion. was invented by the Prussian chemist Lieutenant Dittmar in April 1869. In December 1909, Dougherty, and A. Rioux were killed by an explosion of Dualin, and ... | https://en.wikipedia.org/wiki?curid=39336973 |
Cylindrocyclophanes are a class of cyclophane, a group of aromatic hydrocarbons composed of two benzene rings attached in a unique structure. were the first cyclophanes found in nature, isolated from a species of cyanobacteria, and have proven to be an interesting group of compounds to study due to their unusual molecu... | https://en.wikipedia.org/wiki?curid=39339970 |
Cylindrocyclophanes A - A, C - C, F, and A also have functional groups on C-29 (R) and C-33 (R) and differ from cylindrocyclophanes A-F mainly in their halogenated functional groups. See the following table for a complete list of functional groups for the known cylindrocyclophanes: When cylindrocyclophane A was discove... | https://en.wikipedia.org/wiki?curid=39339970 |
Cylindrocyclophanes The team at University of Illinois-Chicago determined that cylindrocyclophanes A, A, and A displayed the greatest inhibition of the proteasome, which they attributed to the dichloromethyl functional group present at R. When the cytotoxicity of cylindrocyclophanes A, C, F were examined, A was twice a... | https://en.wikipedia.org/wiki?curid=39339970 |
Cylindrocyclophanes For synthesis of cylindrocyclophane F, this reduced the number of steps to 11 and increased the yield to 22%. This process was also able to be applied to the synthesis of cylindrocyclophane A in a 16-step reaction with an 8.1% yield. Significant increase in yield was accomplished when a head-to-tail... | https://en.wikipedia.org/wiki?curid=39339970 |
Silver overlay is an electroplated coating of silver on a non-conductive surface such as porcelain or glass. Most techniques used to create silver overlay involve the use of special flux which contains silver and turpentine oil. This is then painted on the glass ornament as a design. After the painting is complete, the... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay The most well known patent holders are Frederick Shirley from the United States of America, whose patent dates to 1879, Erard and Round who were under the auspices of Stevens & Williams Ltd. whose patent is from 1889, John Sharling also of the USA, whose patent is from 1893 and Friedrich Deusch, the Germ... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay Parallel to the development of German silver overlay, silver overlay production was also initiated in the United States. The specific feature of German silver overlay is the degree of purity – 925 for Sterling silver or 999 for fine silver. The quality of silver used for German overlay can be seen by ide... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay The next step was to galvanize the item with the purest silver (1000). It was very important to monitor items being overlaid with silver – waiting too long resulted in visible dark spots and slight roughness where the cathode or anode were fixed. The cathode and anode were used to charge the item electro... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay Alfred, and later his son Manfred Veyhl, were the only ones who used a varnish to avoid silver oxidation. Alfred used more softer and rounder lines in his designs, whereas Manfred had a more angular, expressive style. A specialty for this company was that clients could choose from a certain range of porc... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay Printed designs were used more often on items produced later, especially those of Manfred Vehyl. These can be recognized by studying the design: if the color is flat and full of small dots, this strongly indicates a printed design. Also, the silver work on printed color designs appears not to cover the d... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay In addition, to these marks, the following marks may also be found: "1000 / 1000 Silber" or "1000 / 1000 Feinsilber". Later items may have the additional mark "Made in Western Germany". Alfred and Manfred Veyhl used many different marks, stamps and labels (always placed on the bottom of the item). Vehyl'... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay The Rockwell Silver Company established in Meriden, CT around 1905 created a number designs which featured silver overlay, however they were merged with Silver City Glass Company in 1978, so even though they have done extensive work, there are no unique marks associated with the company. The Gorham Manuf... | https://en.wikipedia.org/wiki?curid=39348113 |
Silver overlay Friedrich Wilhelm Spahr created timeless designs which can be found today all over Europe and even in the United States. These are rare, desirable and mostly exquisite. was a very exclusive luxury ware from the beginning because of the very complicated and time-consuming steps of manufacturing. items wer... | https://en.wikipedia.org/wiki?curid=39348113 |
Singlet fission is a spin-allowed process, unique to molecular photophysics, whereby one singlet excited state is converted into two triplet states. The phenomenon has been observed in molecular crystals, aggregates, disordered thin films, and covalently-linked dimers, where the chromophores are oriented such that the ... | https://en.wikipedia.org/wiki?curid=39352563 |
Singlet fission Intramolecular singlet fission in covalently linked pentacene and tetracene dimers has also been reported. The detailed mechanism of the process is unknown. Particularly, the role of charge transfer states in the singlet fission process is still debated. Typically, the mechanisms for singlet fission are... | https://en.wikipedia.org/wiki?curid=39352563 |
Fluorenylidene 9-is an aryl carbene derived from the bridging methylene group of fluorene. has the unusual property that the triplet ground state is only 1.1 kcal/mol (4.6 kJ/mol) lower in energy than the singlet state. For this reason, fluorenylidene has been studied extensively in organic chemistry. is a reactive int... | https://en.wikipedia.org/wiki?curid=39355292 |
Fluorenylidene can be produced by photolysis of 9-diazofluorene (DAF). Ultra-fast (300 fs) time resolved laser-flash photolysis of DAF implicates a four-step process in the formation of fluorenylidene by irradiation of 9-diazofluorene. reacts with olefins as predicted by the Skell-Woodworth rules. The stereochemistry o... | https://en.wikipedia.org/wiki?curid=39355292 |
Melvin Mooney Distinguished Technology Award The is a professional award conferred by the American Chemical Society, Rubber Division. Established in 1983, the award is named after Melvin Mooney, developer of the Mooney viscometer and of the Mooney-Rivlin hyperelastic law. The award consists of an engraved plaque and pr... | https://en.wikipedia.org/wiki?curid=39355617 |
Tetrahydroxyflavone may refer to: | https://en.wikipedia.org/wiki?curid=39358105 |
Pentahydroxyflavone may refer to: | https://en.wikipedia.org/wiki?curid=39358124 |
Phase Transitions and Critical Phenomena is a 20-volume series of books, comprising review articles on phase transitions and critical phenomena, published during 1972-2001. It is "considered the most authoritative series on the topic". Volumes 1-6 were edited by Cyril Domb and Melville S. Green, and after Green's death... | https://en.wikipedia.org/wiki?curid=39359065 |
Biological aspects of fluorine Fluorine may interact with biological systems in the form of fluorine-containing compounds. Though elemental fluorine (F) is very rare in everyday life, hundreds of fluorine-containing compounds occur naturally as minerals, medicines, pesticides, and materials. Naturally occurring organof... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Organofluorine in the form of its radioisotope F is also at the heart of a modern medical imaging technique known as positron emission tomography (PET). A PET scan produces three-dimensional colored images of parts of the body that use a lot of sugar, particularly the brain or tumors. Sin... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Water fluoridation is the controlled addition of fluoride to a public water supply in an effort to reduce tooth decay in people who drink the water. Its use began in the 1940s, following studies of children in a region where water is naturally fluoridated. It is now used widely in public ... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Gels and foams are often advised for special patient groups, particularly those undergoing radiation therapy to the head (cancer patients). The patient receives a four-minute application of a high amount of fluoride. Varnishes, which can be more quickly applied, exist and perform a simila... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Adding fluorine to biologically active organic compounds increases their lipophilicity (ability to dissolve in fats), because the carbon–fluorine bond is even more hydrophobic than the carbon–hydrogen bond. This effect often increases a drug's bioavailability because of increased cell mem... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Prior to the 1980s, antidepressants altered not only serotonin uptake but also the uptake of altered norepinephrine; the latter caused most of the side effects of antidepressants. The first drug to alter only the serotonin uptake was Prozac; it gave birth to the extensive selective seroto... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Fluorine compounds are highly amenable to nuclear magnetic resonance (NMR), because fluorine-19 has a nuclear spin of , a high nuclear magnetic moment, and a high magnetogyric ratio. Fluorine compounds typically have a fast NMR relaxation, which enables the use of fast averaging to obtain... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Both partial and complete filling of the lungs have been considered, although only the former has undergone any significant tests in humans. Several animal tests have been performed and there have been some human partial liquid ventilation trials. One effort, by Alliance Pharmaceuticals, ... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Fluoroacetate is similar to acetate, which has a pivotal role in the Krebs cycle (a key part of cell metabolism). Fluoroacetate halts the cycle and causes cells to be deprived of energy. Several other insecticides contain sodium fluoride, which is much less toxic than fluoroacetate. Insec... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Fluoride is considered a semi-essential element for humans: not necessary to sustain life, but contributing (within narrow limits of daily intake) to dental health and bone strength. Daily requirements for fluorine in humans vary with age and sex, ranging from 0.01 mg in infants below 6 m... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Even though it is from a chemical perspective a relatively weak acid, it is far more dangerous than conventional strong mineral acids, such as nitric acid, sulfuric acid, or hydrochloric acid. Owing to its lesser chemical dissociation in water (remaining a neutral molecule), hydrogen fluo... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Skin burns can be treated with a water wash and 2.5 percent calcium gluconate gel or special rinsing solutions. Because HF is absorbed, further medical treatment is necessary. Calcium gluconate may be injected or administered intravenously. Use of calcium chloride is contraindicated and m... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine Malfunction of water fluoridation equipment has occurred several times, including an Alaskan incident that sickened nearly 300 people and killed one. Because of the strength of the carbon–fluorine bond, organofluorines endure in the environment. Perfluorinated compounds (PFCs) have attrac... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine the two chemicals have been found at different concentrations in different populations; for example, one study showed more PFOS than PFOA in Germans, while another study showed the reverse for Americans. PFCs may be starting to decrease in the biosphere: one study indicated that PFOS leve... | https://en.wikipedia.org/wiki?curid=39367145 |
Biological aspects of fluorine PPAR-alpha is a protein that interacts with PFAAs and is commonly implicated in contaminant-caused rodent cancers. Less fluorinated chemicals (i.e. not perfluorinated compounds) can also be detected in the environment. Because biological systems do not metabolize fluorinated molecules eas... | https://en.wikipedia.org/wiki?curid=39367145 |
Phases of fluorine Fluorine forms diatomic molecules () that are gaseous at room temperature with a density about 1.3 times that of air. Though sometimes cited as yellow-green, pure fluorine gas is actually a very pale yellow. The color can only be observed in concentrated fluorine gas when looking down the axis of lon... | https://en.wikipedia.org/wiki?curid=39368969 |
Phases of fluorine The solid state phase change requires more energy than the melting point transition and can be violent, shattering samples and blowing out sample holder windows. Solid fluorine received significant study in the 1920s and 30s, but relatively less until the 1960s. The crystal structure of alpha-fluorin... | https://en.wikipedia.org/wiki?curid=39368969 |
Residual sodium carbonate index The residual sodium carbonate (RSC) index of irrigation water or soil water is used to indicate the alkalinity hazard for soil. The RSC index is used to find the suitability of the water for irrigation in clay soils which have a high cation exchange capacity. When dissolved sodium in com... | https://en.wikipedia.org/wiki?curid=39374186 |
Residual sodium carbonate index Lime [Ca(OH)] can be present in natural water when rain water comes in contact with calcined minerals such as ash produced from the burning of calcareous coal or lignite in boilers. Anthropogenic use of soda ash also finally adds to the RSC of the river water. Where the river water and g... | https://en.wikipedia.org/wiki?curid=39374186 |
Residual sodium carbonate index The endorheic basin lakes are called soda or alkaline lakes when the water inflows contain high concentrations of NaCO. The pH of the soda lake water is generally above 9 and sometimes the salinity is close to brackish water due to depletion of pure water by solar evaporation. Soda lakes... | https://en.wikipedia.org/wiki?curid=39374186 |
C16H20N4O2 The molecular formula CHNO (molar mass: 300.36 g/mol) may refer to: | https://en.wikipedia.org/wiki?curid=39375353 |
Fluorochemical industry The global market for chemicals from fluorine was about US$16 billion per year as of 2006. The industry was predicted to reach 2.6 million metric tons per year by 2015. The largest market is the United States. Western Europe is the second largest. Asia Pacific is the fastest growing region of pr... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry Fluorite of the acidspar grade is used directly as an additive to ceramics and enamels, glass fibers and clouded glass, and cement, as well as in the outer coating of welding rods. Acidspar is primarily used for making hydrofluoric acid, which is a chemical intermediate for most fluorine-contain... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry Other inorganic fluorides made in large quantities include cobalt difluoride (for organofluorine synthesis), nickel difluoride (electronics), lithium fluoride (a flux), sodium fluoride (water fluoridation), potassium fluoride (flux), and ammonium fluoride (various). Sodium and potassium bifluori... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry Production of CFCs grew strongly through the 1980s, primarily for refrigeration and air conditioning but also for propellants and solvents. Since the end use of these materials is banned in most countries, this industry has shrunk dramatically. By the early 21st century, production of CFCs was l... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry As of about 2006–2007, estimates of the global fluoropolymer production varied from over 100,000 to 180,000 metric tons per year. Yearly revenue estimates ranged from over $2.5 billion to over $3.5 billion. Polytetrafluoroethylene (PTFE) is 60–80% of the world's fluoropolymer production on a wei... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry ePTFE is used in rainwear, protective apparel and liquids and gas filters. PTFE can also be formed into fibers which are used in pump packing seals and bag house filters for industries with corrosive exhausts. Other fluoropolymers tend to have similar properties to PTFE—high chemical resistance ... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry Recently, the fuel cell application has reemerged; significant research is being conducted and investments made related to getting proton exchange membrane (PEM) fuel cells into vehicles. Fluoroelastomers are rubber-like substances that are composed of crosslinked mixtures of fluoropolymers. Vit... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry DWR is applied to fabrics by "dip-squeeze-dry" (immersion in DWR-water bath, pressing water out, and then drying). For countries with available data (free-market countries), about 17,000 metric tons of fluorine are produced per year by 11 companies, all G7-resident. Fluorine is relatively inexpe... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry As of 2013, 686,500 metric tons of UF6, containing about 470,000 metric tons of depleted uranium (the remainder being fluorine), were stored at the Paducah Gaseous Diffusion Plant, the USEC's Piketon site, Ohio and the East Tennessee Technology Park (formerly known as the K-25 Site). The second ... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry For making niche organofluorines and fluorine-containing pharmaceuticals, direct fluorination is usually too hard to control. Preparation of intermediate strength fluorinators from fluorine gas solves this problem. The halogen fluorides ClF, BrF, and IF provide gentler fluorination, with a serie... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry Potassium bifluoride increases the electrical conductivity of the solution and provides the bifluoride anion, which releases fluorine at the anode (negative part of the cell). If HF alone is electrolyzed, hydrogen forms at the cathode (positive part of the cell) and the fluoride ions remain in s... | https://en.wikipedia.org/wiki?curid=39379160 |
Fluorochemical industry In 1986, when preparing for a conference to celebrate the 100th anniversary of the discovery of fluorine, Karl O. Christe discovered a purely chemical preparation of fluorine gas; however, he stated in his work that the basics were known 50 years before the actual reaction. The main idea is that... | https://en.wikipedia.org/wiki?curid=39379160 |
George E. Davis Medal The is a medal of the IChemE given not more frequently than every three years, for achievements in chemical engineering. It is named after George E. Davis. Source: IChemE | https://en.wikipedia.org/wiki?curid=39387700 |
Modes of toxic action A mode of toxic action is a common set of physiological and behavioral signs that characterize a type of adverse biological response. A mode of action should not be confused with mechanism of action, which refer to the biochemical processes underlying a given mode of action. are important, widely ... | https://en.wikipedia.org/wiki?curid=39392026 |
Modes of toxic action Toxicants that at low concentrations modify or inhibit some biological process by binding at a specific site or molecule have a specific acting mode of toxic action. However, at high enough concentrations, toxicants with specific acting modes of toxic actions can produce narcosis that may or may n... | https://en.wikipedia.org/wiki?curid=39392026 |
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