AcetyleneNitrogenase: An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 1.18.6.1.EthaneNitrogen Fixation: The process in certain BACTERIA; FUNGI; and CYANOBACTERIA converting free atmospheric NITROGEN to biologically usable forms of nitrogen, such as AMMONIA; NITRATES; and amino compounds.Alkynes: Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.Tungsten: Tungsten. A metallic element with the atomic symbol W, atomic number 74, and atomic weight 183.85. It is used in many manufacturing applications, including increasing the hardness, toughness, and tensile strength of steel; manufacture of filaments for incandescent light bulbs; and in contact points for automotive and electrical apparatus.Azotobacter: A genus of gram-negative, aerobic bacteria found in soil and water. Its organisms occur singly, in pairs or irregular clumps, and sometimes in chains of varying lengths.Nitrosomonas: A genus of gram-negative, ellipsoidal or rod-shaped bacteria whose major source of energy and reducing power is from the oxidation of ammonia to nitrite. Its species occur in soils, oceans, lakes, rivers, and sewage disposal systems.Hydrocarbons, Acyclic: Organic compounds composed exclusively of carbon and hydrogen where no carbon atoms join to form a ring structure.Ethylenes: Derivatives of ethylene, a simple organic gas of biological origin with many industrial and biological use.Molybdoferredoxin: A non-heme iron-sulfur protein isolated from Clostridium pasteurianum and other bacteria. It is a component of NITROGENASE, which is active in nitrogen fixation, and consists of two subunits with molecular weights of 59.5 kDa and 50.7 kDa, respectively.Nitrous Oxide: Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.Hydrogen: The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.Deltaproteobacteria: A group of PROTEOBACTERIA represented by morphologically diverse, anaerobic sulfidogens. Some members of this group are considered bacterial predators, having bacteriolytic properties.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Azotobacter vinelandii: A species of gram-negative, aerobic bacteria first isolated from soil in Vineland, New Jersey. Ammonium and nitrate are used as nitrogen sources by this bacterium. It is distinguished from other members of its genus by the ability to use rhamnose as a carbon source. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Methane: The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)Molybdenum: A metallic element with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. (From Dorland, 27th ed)Spirillum: A genus of gram-negative, curved and spiral-shaped bacteria found in stagnant, freshwater environments. These organisms are motile by bipolar tufts of flagella having a long wavelength and about one helical turn. Some species of Spirillum cause a form of RAT-BITE FEVER.PropaneAmmonia: A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Biofuels: Hydrocarbon-rich byproducts from the non-fossilized BIOMASS that are combusted to generate energy as opposed to fossilized hydrocarbon deposits (FOSSIL FUELS).Investments: Use for articles on the investing of funds for income or profit.Coal: A natural fuel formed by partial decomposition of vegetable matter under certain environmental conditions.Fossil Fuels: Any combustible hydrocarbon deposit formed from the remains of prehistoric organisms. Examples are petroleum, coal, and natural gas.FiresIncineration: High temperature destruction of waste by burning with subsequent reduction to ashes or conversion to an inert mass.Wood: A product of hard secondary xylem composed of CELLULOSE, hemicellulose, and LIGNANS, that is under the bark of trees and shrubs. It is used in construction and as a source of CHARCOAL and many other products.Heating: The application of heat to raise the temperature of the environment, ambient or local, or the systems for accomplishing this effect. It is distinguished from HEAT, the physical property and principle of physics.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Nitrification: A process facilitated by specialized bacteria involving the oxidation of ammonium to nitrite and nitrate.Ventriculography, First-Pass: Radionuclide ventriculography where a bolus of radionuclide is injected and data are recorded from one pass through the heart ventricle. Left and right ventricular function can be analyzed independently during this technique. First-pass ventriculography is preferred over GATED BLOOD-POOL IMAGING for assessing right ventricular function.Denitrification: Nitrate reduction process generally mediated by anaerobic bacteria by which nitrogen available to plants is converted to a gaseous form and lost from the soil or water column. It is a part of the nitrogen cycle.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.PubMed: A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.Steam: Water in its gaseous state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Silicon Dioxide: Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.Polyethylene Glycols: Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Silicosis: A form of pneumoconiosis resulting from inhalation of dust containing crystalline form of SILICON DIOXIDE, usually in the form of quartz. Amorphous silica is relatively nontoxic.Chemistry, Pharmaceutical: Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.Cold Temperature: An absence of warmth or heat or a temperature notably below an accustomed norm.Cyperus: A plant genus of the family CYPERACEAE. SESQUITERPENES are found in some of the species.Chemical Hazard Release: Uncontrolled release of a chemical from its containment that either threatens to, or does, cause exposure to a chemical hazard. Such an incident may occur accidentally or deliberately.Yellow Fever: An acute infectious disease primarily of the tropics, caused by a virus and transmitted to man by mosquitoes of the genera Aedes and Haemagogus. The severe form is characterized by fever, HEMOLYTIC JAUNDICE, and renal damage.Polyesters: Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.Hazardous Substances: Elements, compounds, mixtures, or solutions that are considered severely harmful to human health and the environment. They include substances that are toxic, corrosive, flammable, or explosive.Oxygenases: Oxidases that specifically introduce DIOXYGEN-derived oxygen atoms into a variety of organic molecules.Cytochrome P-450 Enzyme System: A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.Mixed Function Oxygenases: Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.7-Alkoxycoumarin O-Dealkylase: A drug-metabolizing enzyme found in the hepatic, placental and intestinal microsomes that metabolizes 7-alkoxycoumarin to 7-hydroxycoumarin. The enzyme is cytochrome P-450- dependent.

Comparative phylogeny of rrs and nifH genes in the Bacillaceae. (1/323)

The rrs (16S rDNA) gene sequences of nitrogen-fixing endospore-forming bacilli isolated from the rhizosphere of wheat and maize were determined in order to infer their phylogenetic position in the Bacillaceae. These rhizosphere strains form a monophyletic cluster with Paenibacillus azotofixans, Paenibacillus polymyxa and Paenibacillus macerans. Two of them (RSA19 and TOD45) had previously been identified as Bacillus circulans (group 2) by phenotypic characterization (API 50CH). Evidence for nitrogen fixation by P. azotofixans, P. polymyxa, P. macerans and putative B. circulans strains RSA19 and TOD45 was provided by acetylene-reduction activity, and confirmed by amplifying and sequencing a nifH fragment (370 nt). The phylogenetic tree of nifH-derived amino acid sequences was compared to the phylogenetic tree of rrs sequences. All Paenibacillus nifH sequences formed a coherent cluster distinct from that of related nitrogen-fixing anaerobic clostridia and Gram-positive high-G+C-content frankiae. The nifH gene was neither detected in the B. circulans type strain (ATCC 4513T) nor in the type strains of Bacillus subtilis, Bacillus cereus, Bacillus alcalophilus, Bacillus simplex, Brevibacillus brevis and Paenibacillus validus. Accordingly, nitrogen fixation among aerobic endospore-forming Firmicutes seems to be restricted to a subset of species in the genus Paenibacillus.  (+info)

Evidence for involvement of gut-associated denitrifying bacteria in emission of nitrous oxide (N(2)O) by earthworms obtained from garden and forest soils. (2/323)

Earthworms (Aporrectodea caliginosa, Lumbricus rubellus, and Octolasion lacteum) obtained from nitrous oxide (N(2)O)-emitting garden soils emitted 0.14 to 0.87 nmol of N(2)O h(-1) g (fresh weight)(-1) under in vivo conditions. L. rubellus obtained from N(2)O-emitting forest soil also emitted N(2)O, which confirmed previous observations (G. R. Karsten and H. L. Drake, Appl. Environ. Microbiol. 63:1878-1882, 1997). In contrast, commercially obtained Lumbricus terrestris did not emit N(2)O; however, such worms emitted N(2)O when they were fed (i.e., preincubated in) garden soils. A. caliginosa, L. rubellus, and O. lacteum substantially increased the rates of N(2)O emission of garden soil columns and microcosms. Extrapolation of the data to in situ conditions indicated that N(2)O emission by earthworms accounted for approximately 33% of the N(2)O emitted by garden soils. In vivo emission of N(2)O by earthworms obtained from both garden and forest soils was greatly stimulated when worms were moistened with sterile solutions of nitrate or nitrite; in contrast, ammonium did not stimulate in vivo emission of N(2)O. In the presence of nitrate, acetylene increased the N(2)O emission rates of earthworms; in contrast, in the presence of nitrite, acetylene had little or no effect on emission of N(2)O. In vivo emission of N(2)O decreased by 80% when earthworms were preincubated in soil supplemented with streptomycin and tetracycline. On a fresh weight basis, the rates of N(2)O emission of dissected earthworm gut sections were substantially higher than the rates of N(2)O emission of dissected worms lacking gut sections, indicating that N(2)O production occurred in the gut rather than on the worm surface. In contrast to living earthworms and gut sections that produced N(2)O under oxic conditions (i.e., in the presence of air), fresh casts (feces) from N(2)O-emitting earthworms produced N(2)O only under anoxic conditions. Collectively, these results indicate that gut-associated denitrifying bacteria are responsible for the in vivo emission of N(2)O by earthworms and contribute to the N(2)O that is emitted from certain terrestrial ecosystems.  (+info)

Diversity in butane monooxygenases among butane-grown bacteria. (3/323)

Butane monooxygenases of butane-grown Pseudomonas butanovora, Mycobacterium vaccae JOB5, and an environmental isolate, CF8, were compared at the physiological level. The presence of butane monooxygenases in these bacteria was indicated by the following results. (i) O(2) was required for butane degradation. (ii) 1-Butanol was produced during butane degradation. (iii) Acetylene inhibited both butane oxidation and 1-butanol production. The responses to the known monooxygenase inactivator, ethylene, and inhibitor, allyl thiourea (ATU), discriminated butane degradation among the three bacteria. Ethylene irreversibly inactivated butane oxidation by P. butanovora but not by M. vaccae or CF8. In contrast, butane oxidation by only CF8 was strongly inhibited by ATU. In all three strains of butane-grown bacteria, specific polypeptides were labeled in the presence of [(14)C]acetylene. The [(14)C]acetylene labeling patterns were different among the three bacteria. Exposure of lactate-grown CF8 and P. butanovora and glucose-grown M. vaccae to butane induced butane oxidation activity as well as the specific acetylene-binding polypeptides. Ammonia was oxidized by all three bacteria. P. butanovora oxidized ammonia to hydroxylamine, while CF8 and M. vaccae produced nitrite. All three bacteria oxidized ethylene to ethylene oxide. Methane oxidation was not detected by any of the bacteria. The results indicate the presence of three distinct butane monooxygenases in butane-grown P. butanovora, M. vaccae, and CF8.  (+info)

Measurement of cardiac output during exercise by open-circuit acetylene uptake. (4/323)

Noninvasive measurement of cardiac output (QT) is problematic during heavy exercise. We report a new approach that avoids unpleasant rebreathing and resultant changes in alveolar PO(2) or PCO(2) by measuring short-term acetylene (C(2)H(2)) uptake by an open-circuit technique, with application of mass balance for the calculation of QT. The method assumes that alveolar and arterial C(2)H(2) pressures are the same, and we account for C(2)H(2) recirculation by extrapolating end-tidal C(2)H(2) back to breath 1 of the maneuver. We correct for incomplete gas mixing by using He in the inspired mixture. The maneuver involves switching the subject to air containing trace amounts of C(2)H(2) and He; ventilation and pressures of He, C(2)H(2), and CO(2) are measured continuously (the latter by mass spectrometer) for 20-25 breaths. Data from three subjects for whom multiple Fick O(2) measurements of QT were available showed that measurement of QT by the Fick method and by the C(2)H(2) technique was statistically similar from rest to 90% of maximal O(2) consumption (VO(2 max)). Data from 12 active women and 12 elite male athletes at rest and 90% of VO(2 max) fell on a single linear relationship, with O(2) consumption (VO(2)) predicting QT values of 9.13, 15.9, 22.6, and 29.4 l/min at VO(2) of 1, 2, 3, and 4 l/min. Mixed venous PO(2) predicted from C(2)H(2)-determined QT, measured VO(2), and arterial O(2) concentration was approximately 20-25 Torr at 90% of VO(2 max) during air breathing and 10-15 Torr during 13% O(2) breathing. This modification of previous gas uptake methods, to avoid rebreathing, produces reasonable data from rest to heavy exercise in normal subjects.  (+info)

Attributes of atmospheric carbon monoxide oxidation by Maine forest soils. (5/323)

CO, one of the most important trace gases, regulates tropospheric methane, hydroxyl radical, and ozone contents. Ten to 25% of the estimated global CO flux may be consumed by soils annually. Depth profiles for (14)CO oxidation and CO concentration indicated that CO oxidation occurred primarily in surface soils and that photooxidation of soil organic matter did not necessarily contribute significantly to CO fluxes. Kinetic analyses revealed that the apparent K(m) was about 18 nM (17 ppm) and the V(max) was 6.9 micromol g (fresh weight)(-1) h(-1); the apparent K(m) was similar to the apparent K(m) for atmospheric methane consumption, but the V(max) was more than 100 times higher. Atmospheric CO oxidation responded sensitively to soil water regimes; decreases in water content in initially saturated soils resulted in increased uptake, and optimum uptake occurred at water contents of 30 to 60%. However, extended drying led to decreased uptake and net CO production. Rewetting could restore CO uptake, albeit with a pronounced hysteresis. The responses to changing temperatures indicated that the optimum temperature for net uptake was between 20 and 25 degrees C and that there was a transition to net production at temperatures above 30 degrees C. The responses to methyl fluoride and acetylene indicated that populations other than ammonia oxidizers and methanotrophs must be involved in forest soils. The response to acetylene was notable, since the strong initial inhibition was reversed after 12 h of incubation; in contrast, methyl fluoride did not have an inhibitory effect. Ammonium did not inhibit CO uptake; the level of nitrite inhibition was initially substantial, but nitrite inhibition was reversible over time. Nitrite inhibition appeared to occur through indirect effects based on abiological formation of NO.  (+info)

Noninvasive cardiac output measurement in orthostasis: pulse contour analysis compared with acetylene rebreathing. (6/323)

We tested the reliability of noninvasive cardiac output (CO) measurement in different body positions by pulse contour analysis (CO(pc)) by using a transmission line model (K. H. Wesseling, B. De Wit, J. A. P. Weber, and N. T. Smith. Adv. Cardiol. Phys. 5, Suppl. II: 16-52, 1983). Acetylene rebreathing (CO(rebr)) was used as a reference method. Twelve subjects (age 21-34 yr) were studied: 1) six in whom CO(rebr) and CO(pc) were measured in the standing and 6 degrees head-down tilt (HDT) postures and 2) six in whom CO was measured in the 30 degrees HDT, supine, 30 degrees head up-tilt (HUT), and 70 degrees HUT postures on a tilt table. The CO(rebr)-to-CO(pc) ratio in (near) the supine position during rebreathing was used as the calibration factor for CO(pc) measurements. Calibrated CO(pc) (CO(cal sup)) consistently overestimated CO in the upright posture. The drop in CO with upright posture was underestimated by approximately 50%. CO(cal sup) and CO(rebr) values did not differ in the 30 degrees HDT position. Changes in the CO(rebr)-to-CO(pc) ratio are highly variable among subjects in response to a change in posture. Therefore, CO(pc) must be recalibrated for each subject in each posture.  (+info)

Two forms of nitrogenase from the photosynthetic bacterium Rhodospirillum rubrum. (7/323)

Acetylene reduction by nitrogenase from Rhodospirillum rubrum, unlike that by other nitrogenases, was recently found by other investigators to require an activation of the iron protein of nitrogenase by an activating system comprising a chromatophore membrane component, adenosine 5'-triphosphate (ATP), and divalent metal ions. In an extension of this work, we observed that the same activating system was also required for nitrogenase-linked H(2) evolution. However, we found that, depending on their nitrogen nutrition regime, R. rubrum cells produced two forms of nitrogenase that differed in their Fe protein components. Cells whose nitrogen supply was totally exhausted before harvest yielded predominantly a form of nitrogenase (A) whose enzymatic activity was not governed by the activating system, whereas cells supplied up to harvest time with N(2) or glutamate yielded predominantly a form of nitrogenase (R) whose enzymatic activity was regulated by the activating system. An unexpected finding was the rapid (less than 10 min in some cases) intracellular conversion of nitrogenase A to nitrogenase R brought about by the addition to nitrogen-starved cells of glutamine, asparagine, or, particularly, ammonia. This finding suggests that mechanisms other than de novo protein synthesis were involved in the conversion of nitrogenase A to the R form. The molecular weights of the Fe protein and Mo-Fe protein components from nitrogenases A and R were the same. However, nitrogenase A appeared to be larger in size, because it had more Fe protein units per Mo-Fe protein than did nitrogenase R. A distinguishing property of the Fe protein from nitrogenase R was its ATP requirement. When combined with the Mo-Fe protein (from either nitrogenase A or nitrogenase R), the R form of Fe protein required a lower ATP concentration but bound or utilized more ATP molecules during acetylene reduction than did the A form of Fe protein. No differences between the Fe proteins from the two forms of nitrogenase were found in the electron paramagnetic resonance spectrum, midpoint oxidation-reduction potential, or sensitivity to iron chelators.  (+info)

Measurement in vivo of hydrogenase-catalysed hydrogen evolution in the presence of nitrogenase enzyme in cyanobacteria. (8/323)

A method was devised that allows measurement in vivo of hydrogenase-catalysed H2 evolution from the cyanobacterium Anabaena cylindrica, independent of nitrogenase activity, which is also present. Addition of low concentrations of reduced Methyl Viologen (1-10mM) to intact heterocystous filaments of the organism resulted in H2 evolution, but produced conditions giving total inhibition of nitrogenase (acetylene-reducing and H2-evolving) activity. That the H2 formed under these conditions was not contributed to by nitrogenase was also supported by the observation that its rate of formation was similar in the dark or with Ar replaced by N2 in the gas phase, and also in view of the pattern of H2 evolution at very low Methyl Viologen concentrations. Conclusive evidence that the H2 formed in the presence of Methyl Viologen was solely hydrogenase-mediated was its evolution even from nitrogenase-free (non-heterocystous) cultures; by contrast 'uptake' hydrogenase activity in such cultures was greatly decreased. The hydrogenase activity was inhibited by CO and little affected by acetylene. Finally the hydrogenase activity was shown to be relatively constant at different stages during the batch growth of the organism, as opposed to nitrogenase activity, which varied.  (+info)

TY - JOUR. T1 - Coordination and adsorption of acetylene in the poly[(vinylcyclopentadienyl)manganese] membrane. AU - Kawakami, Hiroyoshi. AU - Tsuda, Kenji. AU - Nishide, Hiroyuki. AU - Tsuchida, Eishun. PY - 1991/1/1. Y1 - 1991/1/1. N2 - A copolymer of (vinylcyclopentadienyl)dicarbonylmanganese (CpMn) and octyl methacrylate forms its acetylene-coordinated complex reversibly and stably in the solvent-free membrane state. Kinetic and equilibrium constants of the acetylene coordination to the CpMn residue in the copolymer membrane are determined spectroscopically in situ. The acetylene coordination parameters are much smaller than those of the corresponding nitrogen coordination. Acetylene transport for the membrane is expected to be selectively augmented due to the coordination of acetylene to the fixed CpMn. However, acetylene transport behavior is in accordance with total immobilization of acetylene on the CpMn residue in the acetylene permeation through the membrane.. AB - A copolymer of ...
TY - JOUR. T1 - Coordination and adsorption of acetylene in the poly[(vinylcyclopentadienyl)manganese] membrane. AU - Kawakami, Hiroyoshi. AU - Tsuda, Kenji. AU - Nishide, Hiroyuki. AU - Tsuchida, Eishun. PY - 1991/1/1. Y1 - 1991/1/1. N2 - A copolymer of (vinylcyclopentadienyl)dicarbonylmanganese (CpMn) and octyl methacrylate forms its acetylene-coordinated complex reversibly and stably in the solvent-free membrane state. Kinetic and equilibrium constants of the acetylene coordination to the CpMn residue in the copolymer membrane are determined spectroscopically in situ. The acetylene coordination parameters are much smaller than those of the corresponding nitrogen coordination. Acetylene transport for the membrane is expected to be selectively augmented due to the coordination of acetylene to the fixed CpMn. However, acetylene transport behavior is in accordance with total immobilization of acetylene on the CpMn residue in the acetylene permeation through the membrane.. AB - A copolymer of ...
Shifts in the electronic transitions for the complexes of phenylacetylene with ammonia, methylamine, and triethylamine clearly indicate the variation in the intermolecular structures of the three complexes. The infrared spectrum of phenylacetylene in the, acetylenic C-H stretching region shows Fermi resonance bands, which act as a sensitive tool to probe the intermolecular structures. The IR-UV double resonance spectra of the three complexes are disparate and signify the formation of distinct structures. The formation of C-H center dot center dot center dot N hydrogen-bonded complex with ammonia and two distinct types of c complexes with methylamine and triethylamine can be inferred from the analysis of electronic and vibrational spectra in combination with ab initio calculations. These complexes clearly point out the fact that marginal changes in the interacting partner can significantly alter the intermolecular structure ...
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Looking for acetylenes? Find out information about acetylenes. or , HC≡CH, a colorless gas. It melts at −80.8°C; and boils at −84.0°C;. Offensive odors often noted in commercial acetylene are due to impurities.... Explanation of acetylenes
Fingerprint Dive into the research topics of Palladium-Catalyzed Addition and Carbonylative Addition of Diaryl Disulfides and Diselenides to Terminal Acetylenes. Together they form a unique fingerprint. ...
TY - JOUR. T1 - Measurement of cardiac output during exercise by open-circuit acetylene uptake. AU - Barker, Rebecca C.. AU - Hopkins, Susan R.. AU - Kellogg, Nancy. AU - Olfert, I. Mark. AU - Brutsaert, Tom D. AU - Gavin, Timothy P.. AU - Entin, Pauline L.. AU - Rice, Anthony J.. AU - Wagner, Peter D.. PY - 1999/10. Y1 - 1999/10. N2 - Noninvasive measurement of cardiac output (Q̇T) is problematic during heavy exercise. We report a new approach that avoids unpleasant rebreathing and resultant changes in alveolar PO2 or PCO2 by measuring short-term acetylene (C2H2) uptake by an open-circuit technique, with application of mass balance for the calculation of Q̇T. The method assumes that alveolar and arterial C2H2 pressures are the same, and we account for C2H2 recirculation by extrapolating end-tidal C2H2 back to breath 1 of the maneuver. We correct for incomplete gas mixing by using He in the inspired mixture. The maneuver involves switching the subject to air containing trace amounts of C2H2 ...
The increasing threats of global warming, rapid depletion of fossil fuels, and increasing energy demands are driving an enormous amount of research into clean renewable sources of energy, flue gas capture technologies, and environmentally friendly energy storage devices, to name a few. Activated carbons present a multipurpose material commonly used in many of these increasingly popular green technologies. A wide range of cross-linked acetylenic polymers of phenylacetylene and 1,3- diethynylbenzene were synthesized and investigated in this thesis to generate materials for electrochemical double layer capacitors, CO2 capture, and hydrogen storage. Chemical activation of the copolymers in the presence of KOH was shown to produce highly microporous carbons with various textural properties. The specific cross-linking densities of the polymer precursors prior to carbonization were shown to greatly affect the carbon yield, surface area, pore volumes and pore sizes of the carbons produced. ...
Acetylene is not especially toxic, but when generated from calcium carbide, it can contain toxic impurities such as traces of phosphine and arsine, which give it a distinct garlic-like smell. It is also highly flammable, as are most light hydrocarbons, hence its use in welding. Its most singular hazard is associated with its intrinsic instability, especially when it is pressurized: under certain conditions acetylene can react in an exothermic addition-type reaction to form a number of products, typically benzene and/or vinylacetylene, possibly in addition to carbon and hydrogen.[citation needed] Consequently, acetylene, if initiated by intense heat or a shockwave, can decompose explosively if the absolute pressure of the gas exceeds about 200 kilopascals (29 psi). Most regulators and pressure gauges on equipment report gauge pressure, and the safe limit for acetylene therefore is 101 kPagage, or 15 psig.[42][43] It is therefore supplied and stored dissolved in acetone or dimethylformamide ...
TY - JOUR. T1 - Synthesis of new vinylsilanes containing an asymmetric silicon via platinum catalyzed hydrosilylation of acetylene and monosubstituted alkynes. AU - Gevorgyan, Vladimir. AU - Borisova, Larisa. AU - Popelis, Juris. AU - Lukevics, Edmunds. AU - Foltynowicz, Zenon. AU - Gulinski, Jacek. AU - Marciniec, Bogdan. PY - 1992/2/4. Y1 - 1992/2/4. N2 - A series of new racemic vinylsilanes has been obtained by hydrosilylation reaction of acetylene and monosubstituted alkynes with (±)-α-NpPhMeSiH and (±)-N(CH2CH2O)3SiCH2PhMeSiH in the presence of platinum-containing catalysts.. AB - A series of new racemic vinylsilanes has been obtained by hydrosilylation reaction of acetylene and monosubstituted alkynes with (±)-α-NpPhMeSiH and (±)-N(CH2CH2O)3SiCH2PhMeSiH in the presence of platinum-containing catalysts.. UR - http://www.scopus.com/inward/record.url?scp=0002291907&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=0002291907&partnerID=8YFLogxK. U2 - ...
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This paper demonstrates an acetylene gas sensor based on an Ag-decorated tin dioxide/reduced graphene oxide (Ag-SnO2/rGO) nanocomposite film, prepared by layer-by-layer (LbL) self-assembly technology. The as-prepared Ag-SnO2/rGO nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrum. The acetylene sensing properties were investigated using different working temperatures and gas concentrations. An optimal temperature of 90 °C was determined, and the Ag-SnO2/rGO nanocomposite sensor exhibited excellent sensing behaviors towards acetylene, in terms of response, repeatability, stability and response/recovery characteristics, which were superior to the pure SnO2 and SnO2/rGO film sensors. The sensing mechanism of the Ag-SnO2/rGO sensor was attributed to the synergistic effect of the ternary nanomaterials, and the heterojunctions created at the interfaces between SnO2 and rGO. This work indicates that the Ag
A nitrogen-fixing bacterium, designated strain 6H33bT, was isolated from a compost pile in Japan. The nitrogenase activity of this strain was detected based on its acetylene-reducing activity under low oxygen concentrations (2-4 %). An analysis of the genes responsible for nitrogen fixation in this strain, nifH and nifD, indicated a close relationship to those of Pseudomonas stutzeri A15 (A1501). Sequence similarity searches based on the 16S rRNA gene sequences showed that strain 6H33bT belongs within the genus Pseudomonas sensu stricto; closest similarity was with Pseudomonas indica (97·3 %). A comparison of several taxonomic characteristics of 6H33bT with those of P. indica and some type strains of the genus Pseudomonas sensu stricto indicated that 6H33bT could be distinguished from P. indica based on the presence of nitrogen fixation ability, the absence of nitrate reduction and denitrification abilities and the utilization of some sugars and organic acids. Phylogenetic analyses and the results of
B.4.3.3.5 Physisorption and Desorption of Nonsolvent Molecules. Since there is one acetylene molecule for every ~59 n-octane molecules in the hydrocarbon feedstock solution, the possible physisorption of solvated acetylene molecules from the external solvent bath to the piston cavity passivated diamond walls must also be evaluated. Experiments [3189] on the physisorption of acetylene on the diamond C(111)-H(1x1) surface from gas phase show that the C2H2 molecule adsorbs nearly flat on terraces but is slightly tilted on defect sites, covering four surface hydrogens. This in-plane orientation of the acetylene monolayer is not unexpected because C2H2 has high p electron density around the C=C triple bond, the most energetically favorable position to be attacked by hydrogen-containing species to form a hydrogen bond, and because electrostatic interactions also favor the horizontal orientation of C2H2 on the diamond surface.. Will n-octane or acetylene be preferentially adsorbed on the passivated ...
Acetylene is a weak acid, but not nearly as weak as alkanes or alkenes. CompoundpK a HF3.2 H 2 O16 NH CH 4 60 H2CH2CH2CH2C CH 2 HCCH 26 Acetylene
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The report generally describes 1-phenyl-2-(trimethylsilyl)-acetylene, examines its uses, production methods, patents. 1-Phenyl-2-(trimethylsilyl)-acetylene
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Team WashU_StLouis The production of a bio-fertilizer could benefit the agricultural industry by decreasing the need for energy intensive nitrogen fixation processes. The nif cluster of Cyanothece 51142 consists of 29 genes that construct and regulate a nitrogenase protein complex, which catalyzes the fixation of atmospheric nitrogen. This year, our iGEM team aims to harness the power of nif to produce ammonia in Escherichia coli. After synthesizing a nif- containing plasmid (34 kbp) using the DNA assembler method (Shao et al 2009) and transforming that plasmid into E. coli, our team tested for nitrogenase activity using the acetylene reduction assay. The transformed E. coli were then compared to wild-type under limited nitrogen conditions to check for a competitive advantage. Future tests will evaluate the expression of various nitrogenase subunits, such as nifD and nifK. Our team also aims to further characterize the promoter sequences of the Cyanothece 51142 nif cluster. Between the cysE and ...
Sampling days in the field have been long yet extremely productive. We have collected nitrogen fixation data on primary producers found in four streams with varying temperatures. We can calculate the rate that primary producers are fixing nitrogen using a technique called Acetylene Reduction Assay or ARA. This is one method of measuring fixation which allows us to compare how rates of fixation change across a temperature gradient. You may be thinking "Whoa! Back up. What is this girl talking about?" Let me explain. Some primary producers, for example, one of my favorites, Nostoc Pink, can take nitrogen gas (N2), which is abundant in the air, and utilize the nitrogen for growth and other critical cellular processes. But for the organism to use the nitrogen from N2 gas, it must be converted into a usable form of nitrogen. One particular enzyme known as nitrogenase allows for some organisms to be able to do just that! This enzyme breaks the bonds in N2 gas, or as we call it, "fixes N2 gas", and ...
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An aqueous slurry composition which is curable at saturated steam pressure and temperature of 360.degree. to 400.degree. F to form a hard porous mass suitable for containing dissolved acetylene gas solutions, comprising lime, crystalline silica, and a thickening agent selected from the group consisting of (a) polyethylene oxide, (b) amorphous glassy silica, (c) a soluble salt of phosphate and a soluble salt of calcium and (d) a soluble salt of phosphate and a neutralizing acid.
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The balanced equation for the combustion of acetylene is 2 H2C2 + 5 O2 ? 4 CO2 + 2 H2O. A combustion reaction occurs when a compound merges with oxygen to release heat in an exothermic...
Page contains details about sodium carboxymethylcellulose-bound urchin-like CoSe2/acetylene black . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Reports emphasize significant developments in process technology for Acetylene that have potential implications for the chemical and energy industries
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GEL COLLOIDAL .........................252/315.1+ MISC CHEMICAL MANUFACTURE ........156/DIG.108 RADIOACTIVE .......................252/634 SILICA ............................423/334+ GEL ROUTE TO GLASS MAKING ........... 501/12 GELATINE ............................ 530/354 JELLIES ...........................426/576 GEMS ................................ 63/32 ARTIFICIAL ........................501/86 CHANGING COLOR BY RADIATION .......378/38 DESIGN ............................D11/89+ SETTING METHODS AND APPARATUS .....29/10 SETTINGS ..........................63/26+ GENEALOGICAL CHARTS TEACHING ..........................434/154+ GENERATOR MOTOR ..................... 310/113 GENERATORS (SEE STEAM, GENERATORS) .. D13/112 ACETYLENE .........................48/1 ACETYLENE .........................48/2 ACETYLENE .........................48/3.R ACETYLENE .........................48/4+ CHEMICAL ..........................422/198+ CHEMICAL PRESSURE IN FIRE EXTINGUISHER ...................169/6+ COMBUSTIBLE ...
Calcium carbide (CaC2) reacts with water to form acetylene (C2H2) gas and calcium hydroxide (Ca(OH)2). If the ΔH for: CaC2(s) + 2H2O(l) = Ca(OH)2(s) + C2H2(g) is -127 kJ, then what is the enthalpy of formation for calcium carbide ...
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Follow these practical tips and guidelines to mitigate or eliminate the risk of injury to themselves or others when transporting and handling acetylene.
A common use of ethyne, also called acetylene, is as a fuel in welding. An acetylene flame can reach temperatures of close to 6,000 degrees Fahrenheit. Acetylene is also used for making carbon...
Marcelo Godoi, Eduardo W. Ricardo, Tiago E. Frizon, Manuela S.T. Rocha, Devender Singh, Márcio W. Paixão, Antonio Luiz Braga, An efficient synthesis of alkynyl selenides and tellurides from terminal acetylenes and diorganyl diselenides or ditellurides catalyzed by recyclable copper oxide nanopowder, Tetrahedron, 2012, 68, 51, ...
The catalytic performance of triazolyl-based molecular gels was investigated in the Huisgen 1,3-dipolar cycloaddition of alkynes and azides. Low-molecular-weight gelators derived from l-valine were synthesized and functionalized with a triazole fragment. The resultant compounds formed gels either with or without copper, in a variety of solvents of different polarity. The gelators coordinated CuI and exhibited a high catalytic activity in the gel phase for the model reaction between phenylacetylene and benzylazide. Additionally, the gels were able to participate in autocatalytic synthesis and the influence of small structural changes on their performance was observed. [-] ...
Two distinct isomers for the binary complex between phenylacetylene and methylamine were observed. The first complex is characterized by the presence of a C-H center dot center dot center dot N hydrogen bond between the acetylenic C-H group and the N atom of methylamine. In the second complex the N-H group of methylamine interacts with the pi electron density of the benzene ring accompanied by a peripheral interaction between the methyl C-H group and the pi electron density of the C C bond. Stabilization energies and Gibbs free energies at the complete basis set (CBS) limit of the coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)] suggest that while the C-H center dot center dot center dot N hydrogen bonded complex is the global minimum, the N-H center dot center dot center dot pi hydrogen bonded complex is a high energy local minimum. The formation of the N-H center dot center dot center dot pi complex could be related to kinetic trapping or higher ...
IspH owes its flexibility to the structure and location of its active site. The enzyme is composed of three structural units that harbor a cubic iron-sulfur cluster at their center. This unusual structure enables the enzyme to accomplish a challenging reaction: converting an allyl alcohol to a mixture of the two isoprene components. While iron-sulfur proteins normally act as electron transmitters (deoxidation and oxidation respectively), the IspH enzyme binds the substrate directly to the iron-sulfur cluster. Basis for industrial applications Apart from acetylene hydratase and nitrogenase, IspH is just the third enzyme known to convert acetylene compounds. In addition, until now there were no known iron-containing catalysts that could carry out this reaction. Thus the newly discovered property of IspH could enable the development of new active pharmaceutical ingredients, particularly for the battle against malaria and tuberculosis ...
An organic compound with the formula C2H2 or HCCH. The first member of the alkynes, acetylene is a gas with a narrow liquid range; the triple point is −81°C (−114°F). The heat of formation (ΔH°f ) is +227 kilojoules/mole, and acetylene is the most ...
An organic compound with the formula C2H2 or HCCH. The first member of the alkynes, acetylene is a gas with a narrow liquid range; the triple point is −81°C (−114°F). The heat of formation (ΔH°f ) is +227 kilojoules/mole, and acetylene is the most ...
Inorganic Hypothesis: There are two theories of origin: Organic (bionic) or Inorganic (abionic). Early theories postulated an inorganic origin when it became apparent that there were widespread deposits of petroleum throughout the world. Dmitri Mendeleev (1877), a Russian and the father of the periodic table of elements, reasoned that metallic carbides deep within Earth reacted with water at high temperatures to form acetylene (C2H2) which subsequently condensed to form heavier hydrocarbons. This reaction is readily reproduced in the laboratory. Other hypotheses (Berthelot, 1860, Mendeleev, 1902) were a modification of the acetylene theory. They theorized that the mantle contained iron carbide which would react with percolating water to form methane: FeC2 + 2H2O = CH4 + FeO2 The problem was and still is the lack of evidence for the existence of iron carbide in the mantle. These theories are referred to as the deep-seated terrestrial hypothesis. Another inorganic hypothesis was suggested by ...
45] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, V.G. Zakrzewski, J.A.Jr., Montgomery, R.E. Stratmann, J.C. Burant, S. Dapprich, J.M. Millam, A.D. Daniels, K.N. Kudin, M.C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski, G.A. Petersson, P.Y. Ayala, Q. Cui, K. Morokuma, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J. Cioslowski, J.V. Ortiz, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, J.L. Andres, M. Head-Gordon, E.S. Replogle and J.A. Pople: "Gaussian 98", In: Gaussian 98, Pittsburgh, PA, 1998 ...
Download summary (PDF). Professor Victor-Emanuel Sahini. Download Presentation and List of publications (PDF). 1. Adina RĂDUCAN, Dumitru OANCEA and Eugen SEGAL. Models for irreversible inactivation in the enzymatic decomposition of hydrogen peroxide and their kinetic treatment by means of graphs. Download Art 1 (PDF). Key words: catalase inactivation, kinetic modelling, graph theory. 2. Mihaela PUIU, Valentin MUNTEAN and Dumitru OANCEA. Modeling kinetic limitations of acetylene detonation. Download Art 2 (PDF). Key words: acetylene detonation, Chapman-Jouguet model, ZND model. 3. Mirela ENACHE, Daniela BULCU, Iuliana ŞERBĂNESCU and Elena VOLANSCHI. Interaction of actinomycin D with anionic surfactant, sodium dodecyl sulphate: spectral and electrochemical investigations. Download Art 3 (PDF). Key words: anticancer drugs, actinomycin D, surfactant, spectral and electrochemical methods. 4. Aurica VÂRLAN, Sorana IONESCU, Soong-Hyuck SUH and Mihaela HILLEBRAND. Modelling of the electrochemical ...
Download summary (PDF). Professor Victor-Emanuel Sahini. Download Presentation and List of publications (PDF). 1. Adina RĂDUCAN, Dumitru OANCEA and Eugen SEGAL. Models for irreversible inactivation in the enzymatic decomposition of hydrogen peroxide and their kinetic treatment by means of graphs. Download Art 1 (PDF). Key words: catalase inactivation, kinetic modelling, graph theory. 2. Mihaela PUIU, Valentin MUNTEAN and Dumitru OANCEA. Modeling kinetic limitations of acetylene detonation. Download Art 2 (PDF). Key words: acetylene detonation, Chapman-Jouguet model, ZND model. 3. Mirela ENACHE, Daniela BULCU, Iuliana ŞERBĂNESCU and Elena VOLANSCHI. Interaction of actinomycin D with anionic surfactant, sodium dodecyl sulphate: spectral and electrochemical investigations. Download Art 3 (PDF). Key words: anticancer drugs, actinomycin D, surfactant, spectral and electrochemical methods. 4. Aurica VÂRLAN, Sorana IONESCU, Soong-Hyuck SUH and Mihaela HILLEBRAND. Modelling of the electrochemical ...
NOTITLE__ =Examples of geometries using symmetry= Below are examples of the use of the SYMMETRY directive in the compound [[Release66:Geometry,GEOMETRY directive]]. The z axis is always the primary rotation axis. When in doubt about which axes and planes are used for the group elements, the keyword print may be added to the SYMMETRY directive to obtain this information. ==,math>C_{s},/math> methanol== The ,math>\sigma_h,/math> plane is the xy plane. geometry units angstroms C 0.11931097 -0.66334875 0.00000000 H 1.20599017 -0.87824237 0.00000000 H -0.32267592 -1.15740001 0.89812652 O -0.01716588 0.78143468 0.00000000 H -1.04379735 0.88169812 0.00000000 symmetry cs end ==,math>C_{2v},/math> water== The z axis is the ,math>C_2,/math> axis and the ,math>\sigma_v,/math> may be either the xz or the yz planes. geometry units au O 0.00000000 0.00000000 0.00000000 H 0.00000000 1.43042809 -1.10715266 symmetry group c2v end ==,math>D_{2h},/math> acetylene== Although acetylene has symmetry ,math>D_{\infty ...
... s are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ... In acetylene, the H-C≡C bond angles are 180°. By virtue of this bond angle, alkynes are rod-like. Correspondingly, cyclic ... This suffix arose as a collapsed form of the end of the word "acetylene". The final "-e" disappears if it is followed by ... Ethyne is commonly called by its trivial name acetylene. In chemistry, the suffix -yne is used to denote the presence of a ...
Grignard reagents of acetylene or alkynes can be used to perform alkynylations on compounds that are liable to polymerization ... When the acetylide is formed from acetylene, the reaction gives an α-ethynyl alcohol. This process is often referred to as ... The Favorskii reaction is an alternative set of reaction conditions, which involves prereaction of the acetylene with an alkali ... Chemist Walter Reppe pioneered catalytic, industrial-scale ethynylations using acetylene with alkali metal and copper(I) ...
Acetylene zipper. Exceptionally facile contrathermodynamic multipositional isomeriazation of alkynes with potassium 3- ...
Two different examples involve Argon gas and 1,3-butadiene in a mole ratio of 1500:1 Argon gas and acetylene in a mole ratio of ... The laboratory synthesis starts from acetylene C2H2. The reaction takes place within a DC discharge at reduced pressure in a ...
"Acetylene tetrabromide". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational ... acetylene tetrabromide) intoxication in man". American Industrial Hygiene Association. 30 (3): 251-256. doi:10.1080/ ...
"CYCLOPROPYL ACETYLENE". chemicalland21.com. Retrieved 31 May 2017. Hudson, C.E.; Bauld, N.L. (1972). "Quantitative analysis of ...
Acetylene zipper. Exceptionally facile contrathermodynamic multipositional isomeriazation of alkynes with potassium 3- ...
ten Brink, Felix (2014). "Chapter 2. Living on acetylene. A Primordial Energy Source". In Kroneck, Peter M. H.; Sosa Torres, ...
Sahoo, Manoj (2007). "Dimethyl Acetylene Dicarboxylate". Synlett. 2007: 2142. doi:10.1055/s-2007-984894. Bandrowski, E. (1877 ...
acétique) acetylene, (Fr. acétylène) achieve, (Old Fr. achever) achievement, (Fr. achèvement) acid, (Fr. acide) aconite, (Fr. ...
Lighting was originally acetylene. Most of the problems experienced with McKeen cars involved the powerplant and drivetrain. As ...
Reppe's synthesis of cyclooctatetraene, which involves treating acetylene at high pressure with a warm mixture of nickel ... I. Über Cyclooctatetraen" [Ring-forming polymerization of acetylene. I. Cyclooctatetraene]. Liebigs Ann. Chem. 560 (1): 1-92. ... Kunichika, Sango (1953). "Cyclopolyolefins Derived from Acetylene". Bulletin of the Institute for Chemical Research, Kyoto ... one-step synthesis of cyclooctatetraene from acetylene, providing material identical to that prepared by Willstätter. Any ...
Applications of calcium carbide include manufacture of acetylene gas, and for generation of acetylene in carbide lamps; ... Approximately 400,000 tonnes are produced this way annually (see Acetylene Preparation). In China, acetylene derived from ... Locally produced acetylene is more economical than using imported oil. Production of calcium carbide in China has been ... The CaC2 content of the product is assayed by measuring the amount of acetylene produced on hydrolysis. As an example, the ...
232 citations Greaves, E. O.; Lock, C. J. L.; Maitlis, P. M. (1968). "Metal-Acetylene Complexes II. Acetylene Complexes of ... 223 citations Maitlis, P. M. (1976). "The Palladium(II)-Induced Oligomerization of Acetylenes: An Organometallic Detective ...
The headlights used acetylene. A total of 6,575 Oldsmobile vehicles were manufactured in 1909, with 5,325 being the Model 20. ...
Kunichika, Sango (1953). "Cyclopolyolefins Derived from Acetylene". Bulletin of the Institute for Chemical Research, Kyoto ...
Bredig, G.; Usoff, A. (1896). "Ist Acetylen ein Elektrolyt?" [Is acetylene an electrolyte?]. Zeitschrift für Elektrochemie. 3: ... which also contains acetylene and propane. Contrary to the isomerization, initiation of the chain occurs mainly as follows: ( ...
It featured acetylene lighting. A top speed of above 30 mph (48 km/h) was claimed. The monocar was joined in November 1922 by a ...
In this process, acetylene is dimerized to give vinyl acetylene, which is then combined with hydrogen chloride to afford 4- ... Furthermore, the intermediate vinyl acetylene is unstable. This "acetylene process" has been replaced by a process which adds ... Until the 1960s, chloroprene production was dominated by the "acetylene process," which was modeled after the original ... "Acetylene Polymers and their Derivatives. II. A New Synthetic Rubber: Chloroprene and its Polymers". J. Am. Chem. Soc. 53 (11 ...
Wallace H. Carothers, Ira Williams, Arnold M. Collins, and James E. Kirby (1937). "Acetylene Polymers and their Derivatives. II ...
... was produced via the intermediacy of vinyl acetylene. In this process, acetylene is dimerized to give vinyl acetylene, which is ... It also arises via the dimerization of acetylene or dehydrogenation of 1,3-butadiene. At one time, chloroprene (2-chloro-1,3- ... "Acetylene Polymers and their Derivatives. II. A New Synthetic Rubber: Chloroprene and its Polymers". J. Am. Chem. Soc. 53 (11 ...
Young, James K.; Moore, Jeffrey S. (1995). "Chapter 12: Acetylenes in nanostructures". In Stang, P.J.; Diederich, F. Modern ... acetylene chemistry. Weinheim: VCH. pp. 415-418. ISBN 9783527290840. Hill, David J.; Mio, Matthew J.; Prince, Ryan B.; Hughes, ...
Acetylene is a major product; however, it appears C2 will insert into carbon-hydrogen bonds. C2 is 2.5 times more likely to ... Mechanism of acetylene formation from reaction with acetone and acetaldehyde". Journal of the American Chemical Society. 92 (19 ... Diatomic carbon will react with acetone and acetaldehyde to produce acetylene by two different pathways. Triplet C2 molecules ...
Toma - Owns Equipment shop, Acetylene. He is voiced by Rie Kugimiya (Japanese) Richian - Accessory shopkeeper; brother of ...
The preparation of acetylene from calcium carbide. Proc. Chem. Soc. p. 15. 1894. Metallic derivatives of acetylene. I. Mercuric ...
It melts at -80.8°C and boils at -84.0°C. Offensive odors often noted in commercial acetylene are due to impurities. Acetylene ... acetylene (əsĕt´əlēn´) or ethyne (ĕth´īn), HC[triple bond]CH, a colorless gas. ... Acetylene How Products Are Made COPYRIGHT 1996 Gale Research Inc.. Acetylene. Background. Acetylene is a colorless, combustible ... Acetylene Chemical Compounds COPYRIGHT 2006 Thomson Gale. Acetylene. OVERVIEW. Acetylene (uh-SET-ill-ene) is the simplest ...
The substance may polymerize. Decomposes on heating and increasing pressure. This generates fire and explosion hazard. The substance is a strong reducing agent. It reacts violently with oxidants and fluorine or chlorine under influence of light. This generates fire and explosion hazard. Reacts with copper, silver, mercury and their salts. This produces shock-sensitive compounds (acetylides ...
The enzyme acetylene hydratase catalyzes the hydration of acetylene to give acetaldehyde. C2H2 + H2O → CH3CHO Acetylene is a ... Acetylene Production Plant and Detailed Process Acetylene at Chemistry Comes Alive! Acetylene, the Principles of Its Generation ... Pure acetylene is odorless, but commercial grades usually have a marked odor due to impurities. As an alkyne, acetylene is ... Since acetylene is a linear symmetrical molecule, it possesses the D∞h point group. At atmospheric pressure, acetylene cannot ...
The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database ...
I. Apparatus and initial observations on acetylene, acetylene-d2, benzene, and benzene-d6, J. Res. NBS, 1964, 68A, 409. [all ... Coats, F.H.; Anderson, R.C., Thermodynamic data from electron-impact measurements on acetylene and substituted acetylenes, J. ... Rosmus, P.; Botschwina, P.; Maier, J.P., On the ionic states of vinylidene and acetylene, Chem. Phys. Lett., 1981, 84, 71. [all ... Shiromaru, H.; Achiba, Y.; Kimura, K.; Lee, Y.T., Determination of the C-H bond dissociation energies of ethylene and acetylene ...
Although the oxy-acetylene processes have been superseded in great measure by modern techniques like M.I.G. welding and plasma- ... Although the oxy-acetylene processes have been superseded in great measure by modern techniques like M.I.G. welding and plasma- ... C. G. Bainbridge and F. Clarke, Oxy-acetylene Welding Repair Manual, B.O.C. Ltd, Waltham Cross, 1968Google Scholar ... BS 1821:1957 Class I oxy-acetylene welding for steel pipelines and pipe assemblies for carrying fluidsGoogle Scholar ...
In enzymology, an acetylene hydratase (EC 4.2.1.112) is a rare example of an enzyme containing tungsten. It catalyzes the ... ten Brink, Felix (2014). "Chapter 2. Living on acetylene. A Primordial Energy Source". In Peter M.H. Kroneck and Martha E. Sosa ... The mechanism is thought to involve attachment of acetylene to the metal followed by nucleophilic attack of water. This enzyme ... The systematic name of this enzyme class is acetaldehyde hydro-lyase (acetylene-forming). Other names in common use include AH ...
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... vinyl acetylene, divinyl acetylene, diacetylene, propadiene, hexadiene, butadienyl acetylene, and methyl acetylene. ... Special Hazards of Acetylene United States Department of Labor.. *Acetylene, the Principles of Its Generation and Use, ... Berthelot oxidized acetylene to yield acetic acid and oxalic acid. He found acetylene could be reduced to form ethylene and ... Acetylene is also used in the acetylene (carbide) lamp, once used by miners (not to be confused with the Davy lamp), on ...
This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on ... But Cassini detected no acetylene on the surface. In addition Cassinis spectrometer detected an absence of water ice on the ... One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen ... The absence of detectable acetylene on the Titan surface can very well have a non-biological explanation, said Mark Allen, ...
Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon... ... Acetylene is an important combustion intermediate and plays a critical role in soot formation. ... Mole Fraction Acetylene Shock Tube Absorption Cross Section Reflected Shock Wave This is a preview of subscription content, log ... Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace ...
Acetylene, dissolved. Chemical name:. Acetylene. Class:. 2.1. Packaging group:. -. EmS code:. _F-D_, _S-U_. Labels:. Extremely ... Acetylene, dissolved. Chemical name:. Acetylene. Language:. English. Class:. 2. Classification code:. F+ ; R12 ; R5 ;R6. ... Acetylene, dissolved. Chemical name:. Acetylene. Language:. English. Class:. 2. Classification code:. F+; R12. R5, R6. ... Acetylene , dissolved. Chemical name:. Acetylene. Class:. 2.1. Packaging group:. -. Labels:. Extremely flammable. Remarksopen ...
An oxy acetylene torch is an affordable and versatile tool used by many people to heat, weld, solder, and cut metal. It uses ... How to Set Up an Oxy Acetylene Torch. ... Connect the acetylene hose to the acetylene regulator and to ... Fasten oxygen and acetylene cylinders in an upright position. If you have a cylinder cart, place both the oxygen and acetylene ... Reduce the acetylene flow by adjusting the torch acetylene valve. The flame should start to produce black smoke around the ...
OSHA is confirming the effective date of its direct final rule that revises the Acetylene Standard for general industry by ... Therefore, OSHA considers acetylene plants in existence prior to the effective date of NFPA 51A-2001 (i.e., February 9, 2001) ... Revising Standards Referenced in the Acetylene Standard. A Rule by the Occupational Safety and Health Administration on 11/10/ ... Two commenters appeared to confuse the Acetylene Standard at 29 CFR 1910.102, which was the subject of this rulemaking, with ...
acetylenes synonyms, acetylenes pronunciation, acetylenes translation, English dictionary definition of acetylenes. n. A ... acetylene. [əˈsetɪliːn]. A. N → acetileno m. B. CPD acetylene burner N → soplete m oxiacetilénico. acetylene lamp N → lámpara f ... acetylene. [əˈsɛtɪliːn] n → acetilene m. acetylene burner → becco ad acetilene. acetylene welding → saldatura ad acetilene ... acetylene. (redirected from acetylenes). Also found in: Thesaurus, Medical, Encyclopedia.. Related to acetylenes: ethyne ...
The century-old challenge of transporting acetylene may have been solved in principle by a team of scientists working at the ... Exceptionally High Acetylene Uptake in a Microporous Metal - Organic Framework With Open Metal Sites. Journal of the American ... Acetylene, widely used in decades past for welding and illumination, is now also valuable as a starting point for synthesizing ... To safely store acetylene, storage cylinders have to be filled with both porous material and liquid solvents such as acetone. ...
https://wilhelmsen.com/product-catalogue/application-areas/container/engine-room/workshop/gases/oxygen-acetylene-cutting/ ...
Regulator: acetylene. • Tank type: B. • CGA tank connection: 520. • Dual or Single stage: single. • Number of gauges: two. • ...
Reports emphasize significant developments in process technology for Acetylene that have potential implications for the ... Also in this report, SRI evaluates the technology of recovering the acetylene that is by-produced in ethylene production and ... Acetylene vs Ethylene as a Chemical Raw Material - Chemical production and investment cost ... The thermal cracking process for producing acetylene, once widely used, has been abandoned. The submerged flame process was ...
Series Title: PPI: Other industrial gases (including fluorocarbon and acetylene); NSA For this series: Numerical Data , Source ... Series Title: PPI: Other industrial gases (including fluorocarbon and acetylene); NSA For this series: Numerical Data , ...
The Global Acetylene Industry 2015 Market Research Report is a professional and in-depth study on the - Market Research Reports ... 1.2 Classification of Acetylene. 1.3 Applications of Acetylene. 1.4 Industry Chain Structure of Acetylene. 1.5 Industry ... Table Specifications of Acetylene. Table Classification of Acetylene. Figure Global Production Market Share of Acetylene by ... 1.5.1 Industry Overview of Acetylene. 1.5.2 Global Major Regions Status of Acetylene. 1.6 Industry Policy Analysis of Acetylene ...
Acetylene is colorless and extremely unstable in its pure form, which is why it is ... Acetylene is a hydrocarbon compound and is the simplest form of alkyne. ... What is an Acetylene Torch?. Acetylene is a hydrocarbon compound and is the simplest form of alkyne. Acetylene is colorless and ... What is an Acetylene Torch?. An acetylene torch is a hand-held torch with one or two hoses that connect to two separate gas ...
What do you think of Acetylene-Air torches? - Im thinking of branching out from silversmithery into building a couple of ... What do you think of Acetylene-Air torches? Im thinking of branching out from silversmithery into building a couple of frames ... and I was wondering if acetylene-air is adequate for brazing a frame. I have a Presto-lite with #2 (itsy)-#5 (1/4 inch) tips. ...
Find Acetylene Oxygen Co Inc located at 11446 Hempstead Rd, Houston, Texas, 77092. Contact 7136811782. Ratings, reviews, hours ... For maps and directions to Acetylene Oxygen Co Inc view the map to the right. For reviews of Acetylene Oxygen Co Inc see below. ... Acetylene Oxygen Co Inc is located at the address 11446 Hempstead Rd in Houston, Texas 77092. They can be contacted via phone ... Acetylene Oxygen Co Inc provides Repairs & Replacements, Fabrication, Demolition to its customers. ...
  • Acetylene-dicarboxylic acid (CAS 142-45-0) Market Research Report 2018 contents were prepared and placed on the website in January, 2018. (marketpublishers.com)
  • Please note that Acetylene-dicarboxylic acid (CAS 142-45-0) Market Research Report 2018 is a half ready publication and contents are subject to change. (marketpublishers.com)
  • 1-Phenyl-2-(trimethylsilyl)-acetylene (CAS 2170-06-1) Market Research Report 2018 contents were worked out and placed on the website in February, 2018. (marketpublishers.com)
  • Please note that 1-Phenyl-2-(trimethylsilyl)-acetylene (CAS 2170-06-1) Market Research Report 2018 is a half ready publication and contents are subject to change. (marketpublishers.com)
  • Albany, US, 2018-Mar-06 - /EPR Network/ - An up-to-date research report has been disclosed by Market Research Hub highlighting the title " Global Acetylene Black Market Report 2018 " which provides an outlook of current market growth as well as the expected forecast including Rate on Investment (ROI) together with growing CAGR near XX% during 2018-2025. (express-press-release.net)
  • The Global Acetylene Cylinder was valued at USD xx million in 2017 and is forecasted to reach USD xx million by 2025, with a CAGR of xx% during the forecast period (2018-2025). (stetsonreporter.com)
  • The competitive position of acetylene relative to ethylene in vinyl chloride and vinyl acetate production and relative to propylene in acrylic acid production is described. (ihs.com)
  • The mercuric chloride catalyst for acetylene hydrochlorination creates vinyl chloride, an important polymer feedstock. (sciencemag.org)
  • A Ru-based catalyst (Ru/N-AC) was prepared using N-doped carbon as the support and the catalytic performance of the one-step synthesis reaction of vinyl chloride monomer (VCM) from acetylene and 1,2-dichloroethane (EDC) was assessed. (rsc.org)
  • Acetylene is easily prepared commercially by the reaction of calcium carbide with water, but is prepared commercially by the pyrolysis of hydrocarbons. (encyclopedia.com)
  • The developed reaction conditions led to high yields of unprotected acetylenes with cyclic, nitro and linear keto esters as well as keto amides. (epfl.ch)
  • This allows a new direct access to chiral acetylene compound in high yields under operationally simple reaction conditions. (epfl.ch)
  • In many instances, the reaction sequence regiospecifically ligates azides and terminal acetylenes to give only 1,4-disubstituted [1,2,triazoles. (freepatentsonline.com)
  • We have performed an in situ x-ray absorption fine structure study of gold/carbon (Au/C) catalysts under acetylene hydrochlorination reaction conditions and show that highly active catalysts comprise single-site cationic Au entities whose activity correlates with the ratio of Au(I):Au(III) present. (sciencemag.org)
  • The making of acetylene gas from the reaction of water with calcium carbide has long been known. (voortrekker-history.co.za)
  • The physical and CO 2 permeation properties of its crosslinked membranes prepared by the cyclotrimerization reaction of the acetylene groups at the polymer chain end using tantalum (V) chloride (TaCl 5 ) as a catalyst under thermal treatment was investigated in terms of CO 2 -induced membrane plasticization. (wiley.com)
  • The cyclotrimerization reaction of the acetylene groups at the polymer chain ends using a transition metal catalyst under thermal treatment was found to be more effective than conventional thermal treatments for suppressing membrane plasticization without the membrane densification. (wiley.com)
  • Development on new intermolecular reductive cyclized reaction of acetylenes and its development to the material science. (worldwidescience.org)
  • Through BET, TG, XPS, ICP, TPR, TPD, TEM and XRD characterization, it is indicated that N-doped AC support can increase the amount of RuO 2 and RuO x species in the catalyst and enhance its adsorption ability for both EDC and acetylene, suggesting that the N dopant and Ru species generated a synergistic effect in the one-step synthesis reaction of VCM. (rsc.org)
  • Acetylene (C 2 H 2 ) can be produced from the reaction of calcium carbide (CaC 2 ) with water. (bartleby.com)
  • No. 3,845,018 and is a multi-step procedure involving the initial reaction of an aromatic tetracarboxylic acid dianhydride such as benzophenone tetracarboxylic acid dianhydride with an aromatic diamine to form an anhydride-capped polyamic acid, which is subsequently reacted with an aminoarylacetylene to produce an acetylene-terminated polyamic acid oligomer, which is then thermally converted to the desired acetylene-substituted polyimide oligomer. (google.com)
  • If the acetylene were burned to form water and carbon dioxide, how many kilojoules of energy would be produced from the complete reaction of 20 of calcium carbide? (jiskha.com)
  • Acetylene is easily prepared commercially by the reaction of calcium carbide carbide, any one of a group of compounds that contain carbon and one other element that is either a metal, boron, or silicon. (thefreedictionary.com)
  • Berthelot was able to prepare acetylene from methyl alcohol, ethyl alcohol, ethylene , or ether , when he passed any one of these as a gas or vapor through a red-hot tube. (newworldencyclopedia.org)
  • The polyamic acid oligomer is thereafter converted to the desired acetylene-terminated polyimide oligomer by heating in the continued presence of said N-methyl-2-pyrrolidone. (google.com)
  • The N-methyl-2-pyrrolidone can then be removed by any suitable means such as by precipitation of the acetylene-substituted polyimide oligomer in a non-solvent such as ethanol. (google.com)
  • citation needed] Since the 1950s, acetylene has mainly been manufactured by the partial combustion of methane or appears as a side product in the ethylene stream from cracking of hydrocarbons. (wikipedia.org)
  • He found acetylene could be reduced to form ethylene and ethane . (newworldencyclopedia.org)
  • In the late 1990s, because of the pressure exerted on the cost of ethylene by the increasing price of oil, interest in the long-dormant subject of acetylene production was renewed. (ihs.com)
  • Also in this report, SRI evaluates the technology of recovering the acetylene that is by-produced in ethylene production and compares the economics of recovery with that of hydrogenation. (ihs.com)
  • The usage of ethylene and acetylene are to be described. (bartleby.com)
  • According to the C-C bond lengths obtained, the adsorbed molecule was modified from acetylene-like into ethylene-like on the δ-MoC(001) surface (desired behavior for hydrogenation reactions) but into ethane-like on TiC(001) and ZrC(001). (osti.gov)
  • The rotational spectrum of the CH$\cdots\pi$ bonded complex between benzene and acetylene has been measured in the $6-20$ GHz range using chirped-pulse Fourier-transform microwave spectroscopy. (illinois.edu)
  • Various configurations of the system composed of benzene and acetylene are investigated in an effort to identify the most stable. (usu.edu)
  • At atmospheric pressure, acetylene cannot exist as a liquid and does not have a melting point. (wikipedia.org)
  • The sublimation point at atmospheric pressure is −84.0 °C. The adiabatic flame temperature in air at atmospheric pressure is 2534 °C.[citation needed] Acetylene gas can be dissolved in acetone or dimethylformamide in room temperature and 1 atm. (wikipedia.org)
  • In the United States alone, several hundred thousand tons of acetylene are produced every year, but its volatility renders it difficult to transport: It becomes dangerously explosive at about 30 psi (207 kilopascal), only about twice normal atmospheric pressure. (scienceblog.com)
  • In our work, stable carboxyl-rich plasma polymers (COOH PPs) were deposited using plasma co-polymerization of maleic anhydride and acetylene at atmospheric pressure using dielectric barrier discharge (DBD). (muni.cz)
  • Approximately 80 percent of the acetylene produced annually in the United States is used in chemical synthesis. (newworldencyclopedia.org)
  • This constitutes a serious limitation, in particular when considering that "classical" C-C bond formation is not adequate for the synthesis of quaternary centers containing an acetylene. (epfl.ch)
  • Some commercially useful acetylene compounds include acetylene black, which is used in certain dry-cell batteries, and acetylenic alcohols, which are used in the synthesis of vitamins. (voortrekker-history.co.za)
  • Trimethylsilyl)acetylene is used in the preparation of trimethylsilanyl-propiolic acid ethyl ester by reacting with carbonochloridic acid ethyl ester as well as in the synthesis of iodoalkenes by radical addition of perfluoroalkyl iodides. (alfa.com)
  • Synthesis routes of novel piperidine-containing acetylenes are presented. (diva-portal.org)
  • It is indicated that 1% Ru/N-AC exhibited good catalytic activity with an initial acetylene conversion of 95.2% at 250 °C, an EDC total liquid hourly space velocity (LHSV) of 0.2 h −1 and a molar ratio n (EDC)/ n (C 2 H 2 ) of 1, much better than that of 1% Ru/AC or N-AC. (rsc.org)
  • Until the 1950s, when oil supplanted coal as the chief source of reduced carbon, acetylene (and the aromatic fraction from coal tar) was the main source of organic chemicals in the chemical industry. (wikipedia.org)
  • Using acetylene, Berthelot was the first to show that an aliphatic compound could form an aromatic compound when he heated acetylene in a glass tube to produce benzene with some toluene . (newworldencyclopedia.org)
  • Acetylene is also used in the acetylene ('carbide') lamp, once used by miners (not to be confused with the Davy lamp), on vintage cars , and still sometimes used by cavers. (newworldencyclopedia.org)
  • In this context, the acetylene is generated by dripping water from the upper chamber of the lamp onto calcium carbide (CaC 2 ) pellets in the base of the lamp. (newworldencyclopedia.org)
  • It was found that the bonding of acetylene was significantly affected by the electronic and structural properties of the carbide surfaces. (osti.gov)
  • The synthetic potential of propargylic nitro compounds bearing free acetylenes was demonstrated by their transformation into propargylic triazoles, hydroxylamines and protected amines, as well as into allyl amines in good yield. (epfl.ch)
  • The chlorination of acetylene is the basis for obtaining trichloroethylene, tetrachloroethane, and other compounds containing chlorine. (thefreedictionary.com)
  • Our results indicate that the aerosols can act as activation centers to drive the photoreactivity of acetylene with the aerosols at the accretion interface at wavelengths where acetylene-ice alone does not show photoreactivity. (astrobiology.com)
  • Because acetylene is so flammable and has a 29 PSI, it cannot be used in underwater applications or other applications that involve high pressure. (tech-faq.com)
  • Removes particulate and acetone droplets from acetylene to 99.99% at 0.1 micron protecting your microcomputer gas controls and AA burner system from contamination and corrosion. (perkinelmer.com)
  • it is only slightly soluble in water and very soluble in acetone (at 15°C, 25 parts of acetylene to 1 part of acetone). (thefreedictionary.com)
  • Since acetylene is a linear symmetrical molecule, it possesses the D∞h point group. (wikipedia.org)
  • The consecutive ion-molecule reactions in acetylene within the pressure limits of 0.00001 and 0.01 torr have been investigated as a function of the energy transferred to the acetylene molecule during the initial ionization by charge exchange with incident positive ions of low kinetic energy. (dtic.mil)
  • Despite many interesting and useful reactions of acetylenes with superbases the most amazing is the "contrathermodynamic" multipositional isomerization of the internal triple bond to the terminal position under the influence of alkali metal amides of ethylenediamine or 1,3-propylenediamine. (thefreedictionary.com)
  • Reactions of acetylenes with noble-metal halides. (alfa.com)
  • In addition to the well-established nucleophilic alkynylation, the use of electrophilic alkynes can expand tremendously the scope of acetylene transfer reactions. (epfl.ch)
  • The report generally describes 1-phenyl-2-(trimethylsilyl)-acetylene, examines its uses, production methods, patents. (marketpublishers.com)
  • 1-phenyl-2-(trimethylsilyl)-acetylene manufacturers and suppliers with contacts and product range are mentioned in the study. (marketpublishers.com)
  • Furthermore, 1-phenyl-2-(trimethylsilyl)-acetylene prices in regional markets can be found in the report with regards to countries and companies. (marketpublishers.com)
  • The report also focuses on 1-phenyl-2-(trimethylsilyl)-acetylene consumers by providing data on companies that use it. (marketpublishers.com)
  • Ribet, J. and Drevon, J.-J. (1995) Phosphorus Deficiency Increases the Acetylene-Induced Decline in Nitrogenase Activity in Soybean (Glycine max (L.) Merr. (scirp.org)
  • Acetylene is an unsaturated organic compound because its four atoms are triple bonded through a covalent bond . (newworldencyclopedia.org)
  • The team has probed the atomic-level workings of a metal-organic framework (MOF), a lattice-like structure made of copper oxide and benzene, that soaks up acetylene like a sponge. (scienceblog.com)
  • The principal raw materials for acetylene manufacture are calcium carbonate ( limestone ) and coal . (newworldencyclopedia.org)
  • F to form a hard porous mass suitable for containing dissolved acetylene gas solutions, comprising lime, crystalline silica, and a thickening agent selected from the group consisting of (a) polyethylene oxide, (b) amorphous glassy silica, (c) a soluble salt of phosphate and a soluble salt of calcium and (d) a soluble salt of phosphate and a neutralizing acid. (patentgenius.com)
  • An apparatus was designed that permitted acetylene reduction (N 2 fixation) by root nodules to be measured in situ simultaneously with net photosynthesis, dark respiration, and transpiration of the shoot in soybean plants ( Glycine max [L.] Merr. (plantphysiol.org)
  • Among them, metal oxides have become important candidates for acetylene sensing due to their unique advantages-such as their small size and simplicity of integration-but they lack selectivity towards different gas species, and often require high operating temperatures and have high power consumption [ 16 , 17 , 18 , 19 , 20 ]. (mdpi.com)
  • At temperatures below the triple point, solid acetylene can change directly to the vapour (gas) by sublimation. (wikipedia.org)
  • Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm −1 over a wide range of temperatures (1000-2200 K) and pressures (1-5 bar). (springer.com)
  • The acetylene sensing properties were investigated using different working temperatures and gas concentrations. (mdpi.com)
  • Many of the acetylenes investigated produce pseudo-first-order time-dependent and NADPH-dependent losses of the dealkylation activities characteristic of mechanism-based irreversible inactivation (suicide inhibition). (nih.gov)
  • Consequently, it was concluded that photosynthesis, transpiration, or some direct effect on the nodules other than that caused by respiration were most likely to account for the inhibition of acetylene reduction at soil water potentials below −2 bars. (plantphysiol.org)
  • A novel fluorine-containing telechelic polyimide end-capped with acetylene group which derived from 4,4-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,4-diaminodiphenyl ether (DADE), and 4-(2-phenylethynyl) phthalic anhydride (PEPA) was synthesized using polycondensation. (wiley.com)
  • A method of homopolymerizing the acetylene-substituted polyimide oligomers described in the U.S. Pat. (google.com)
  • Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. (springer.com)
  • The anharmonic interaction coupling terms known to occur from a pure vibrational fit in this acetylene isotopologue are included in the model. (osu.edu)
  • entitled "POLYMERIC MATERIAL MADE FROM SILOXANE-ACETYLENE POLYMER CONTAINING METAL-ACETYLENE COMPLEX," designated as NC 97,123, and filed on the same day as the present application is incorporated by reference. (google.com)
  • Section 8: Exposure Controls/Personal Protection Exposure Guidelines ACETYLENE, DISSOVED: ACETYLENE: ACGIH (simple asphyxiant) 2500 ppm (2662 mg/m3) NIOSH recommended ceiling Engineering Controls Handle only in fully enclosed systems or with adequate ventilation. (voortrekker-history.co.za)
  • A comprehensive study of acetylene adsorption on δ-MoC(001), TiC(001) and ZrC(001) surfaces was carried out by means of calculations based on periodic density functional theory, using the Perdew-Burke-Ernzerhof exchange-correlation functional. (osti.gov)
  • The interaction of acetylene with the TiC(001) and ZrC(001) surfaces was strong (binding energies higher than $-$3.5 eV), while moderate acetylene adsorption energies were observed on δ-MoC(001) ($-$1.78 eV to -0.66 eV). (osti.gov)