An experimental study of adsorption interference in binary mixtures flowing through activated carbon

NASA Technical Reports Server (NTRS)

Madey, R.; Photinos, P. J.

1983-01-01

The isothermal transmission through activated carbon adsorber beds at 25 C of acetaldehyde-propane and acetylene-ethane mixtures in a helium carrier gas was measured. The inlet concentration of each component was in the range between 10 ppm and 500 ppm. The constant inlet volumetric flow rate was controlled at 200 cc (STP)/min in the acetaldehyde-propane experiments and at 50 cc (STP)/min in the acetaldehyde-ethane experiments. Comparison of experimental results with the corresponding single-component experiments under similar conditions reveals interference phenomena between the components of the mixtures as evidenced by changes in both the adsorption capacity and the dispersion number. Propane was found to displace acetaldehyde from the adsorbed state. The outlet concentration profiles of propane in the binary mixtures tend to become more diffuse than the corresponding concentration profiles of the one-component experiments. Similar features were observed with mixtures of acetylene and ethane; however, the displacement of acetylene by ethane is less pronounced.

First total syntheses of (Z)-15-methyl-10-hexadecenoic acid and the (Z)-13-methyl-8-tetradecenoic acid

PubMed Central

Carballeira, Néstor M.; Montano, Nashbly; Padilla, Luis F.

2006-01-01

The first total syntheses for the (Z)-15-methyl-10-hexadecenoic acid and the (Z)-13-methyl-8-tetradecenoic acid were accomplished in seven steps and in 31–32% overall yields. The (trimethylsilyl)acetylene was the key reagent in both syntheses. It is proposed that the best synthetic strategy towards monounsaturated iso methyl-branched fatty acids with double bonds close to the ω end of the acyl chain is first acetylide coupling of (trimethylsilyl)acetylene to a long-chain bifunctional bromoalkane followed by a second acetylide coupling to a short-chain iso bromoalkane, since higher yields are thus obtained. Spectral data is also presented for the first time for these two unusual fatty acids with potential as biomarkers and as topoisomerase I inhibitors. PMID:17125759

Laboratory IR Studies and Astrophysical Implications of C2H2-Containing Binary Ices

NASA Technical Reports Server (NTRS)

Knez, C.; Moore, M.; Ferrante, R.; Hudson, R.

2012-01-01

Studies of molecular hot cores and protostellar environments have shown that the observed abundance of gas-phase acetylene (C2H2) cannot be matched by chemical models without the inclusion of C2H2 molecules subliming from icy grain mantles. Searches for infrared (IR) spectral features of solid-phase acetylene are under way, but few laboratory reference spectra of C2H2 in icy mixtures, which are needed for spectral fits to observational data, have been published. Here, we report a systematic study of the IR spectra of condensed-phase pure acetylene and acetylene in ices dominated by carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water (H2O). We present new spectral data for these ices, including band positions and intrinsic band strengths. For each ice mixture and concentration, we also explore the dependence of acetylene's nu5-band position (743 cm-1, 13.46 micrometers) and FWHM on temperature. Our results show that the nu5 feature is much more cleanly resolved in ices dominated by non-polar and low-polarity molecules, specifically CO, CO2, and CH4, than in mixtures dominated by H2O-ice. We compare our laboratory ice spectra with observations of a quiescent region in Serpens.

Carbon particles

DOEpatents

Hunt, Arlon J.

1984-01-01

A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

Carbon-particle generator

DOEpatents

Hunt, A.J.

1982-09-29

A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Detering, B.A.; Kong, P.C.; Thomas, C.P.

This paper describes the experimental demonstration of a process for direct conversion of methane to acetylene in a thermal plasma. The process utilizes a thermal plasma to dissociate methane and form an equilibrium mixture of acetylene followed by a supersonic expansion of the hot gas to preserve the produced acetylene in high yield. The high translational velocities and rapid cooling result in an overpopulation of atomic hydrogen which persists throughout the expansion process. The presence of atomic hydrogen shifts the equilibrium composition by inhibiting complete pyrolysis of methane and acetylene to solid carbon. This process has the potential to reducemore » the cost of producing acetylene from natural gas. Acetylene and hydrogen produced by this process could be used directly as industrial gases, building blocks for synthesis of industrial chemicals, or oligomerized to long chain liquid hydrocarbons for use as fuels. This process produces hydrogen and ultrafine carbon black in addition to acetylene.« less

Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

NASA Astrophysics Data System (ADS)

Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

2017-03-01

A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

Development of Nanoporous Carbide-Derived Carbon Electrodes for High-Performance Lithium-Ion Batteries

DTIC Science & Technology

2011-09-01

carbon produced from TiC (From [10]). .................................... 27 Figure 9. LiFePO4 , acetylene black, and PVDF powders in weighing boat...dispenser, and the ball milled powder mixture x containing LiFePO4 , acetylene black, and PVDF binder; and b) Prepared slurry after adding NMP solvent to...the powder mixture. ..... 39 Figure 12. Sample vial containing a LiFePO4 slurry inside the ultrasonic bath. Each vial was sonicated for 30 minutes

Fuel-air munition and device

DOEpatents

Carlson, Gary A.

1976-01-01

An aerially delivered fuel-air munition consisting of an impermeable tank filled with a pressurized liquid fuel and joined at its two opposite ends with a nose section and a tail assembly respectively to complete an aerodynamic shape. On impact the tank is explosively ruptured to permit dispersal of the fuel in the form of a fuel-air cloud which is detonated after a preselected time delay by means of high explosive initiators ejected from the tail assembly. The primary component in the fuel is methylacetylene, propadiene, or mixtures thereof to which is added a small mole fraction of a relatively high vapor pressure liquid diluent or a dissolved gas diluent having a low solubility in the primary component.

OZONE PRODUCTION FROM IRRADIATION OF ACETYLENE/CHLORINE MIXTURES IN AIR

EPA Science Inventory

The reaction of chlorine radicals with acetylene in air in the absence of oxides of nitrogen result In the formation of ozone. o ozone is observed when chlorine radicals react with methylacetylene or ethylacetylene under similar conditions. ormyl chloride is observed in all syste...

Synthesis and Reactivity of 1-Methyl-e-Ethynylpyridinium Triflate

DTIC Science & Technology

1992-05-15

Approved for public release, distribution unlimited 13. ABSTRACT (Maximum 200 words) 1- Methyl -4-ethynylpyridiniurn triflate has been prepared by treatment of... treatment of 4-ethynylpyrdine with methyl tinflase in methylene chloride. I his new native acetylenic monomer timerized to tris. 1.3.5-( I...described their conversion to polymers with regular structure.8.9 Using the analogy to vinylpyridine, we examined reactions of 1 with triflic acid and methyl

Detonation engine fed by acetylene-oxygen mixture

NASA Astrophysics Data System (ADS)

Smirnov, N. N.; Betelin, V. B.; Nikitin, V. F.; Phylippov, Yu. G.; Koo, Jaye

2014-11-01

The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman-Jouguet detonation parameters.

Photochemical processes on Titan: Irradiation of mixtures of gases that simulate Titan's atmosphere

NASA Astrophysics Data System (ADS)

Tran, Buu N.; Joseph, Jeffrey C.; Force, Michael; Briggs, Robert G.; Vuitton, Veronique; Ferris, James P.

2005-09-01

Photochemical reaction pathways in Titan's atmosphere were investigated by irradiation of the individual components and the mixture containing nitrogen, methane, hydrogen, acetylene, ethylene, and cyanoacetylene. The quantum yields for the loss of the reactants and the formation of products were determined. Photolysis of ethylene yields mainly saturated compounds (ethane, propane, and butane) while photolysis of acetylene yields the same saturated compounds as well as ethylene and diacetylene. Irradiation of cyanoacetylene yields mainly hydrogen cyanide and small amounts of acetonitrile. When an amount of methane corresponding to its mixing ratio on Titan was added to these mixtures the quantum yields for the loss of reactants decreased and the quantum yields for hydrocarbon formation increased indicative of a hydrogen atom abstraction from methane by the photochemically generated radicals. GC/MS analysis of the products formed by irradiation of mixtures of all these gases generated over 120 compounds which were mainly aliphatic hydrocarbons containing double and triple bonds along with much smaller amounts of aromatic compounds like benzene, toluene and phenylacetylene. The reaction pathways were investigated by the use of 13C acetylene in these gas mixtures. No polycyclic aromatic compounds were detected. Vapor pressures of these compounds under conditions present in Titan's atmosphere were calculated. The low molecular weight compounds likely to be present in the atmosphere and aerosols of Titan as a result of photochemical processes are proposed.

Siloxane containing addition polyimides. II - Acetylene terminated polyimides

NASA Technical Reports Server (NTRS)

Maudgal, S.; St. Clair, T. L.

1984-01-01

Acetylene terminated polyimide oligomers having a range of molecular weights have been synthesized by reacting bis (gamma-aminopropyl) tetramethyldisiloxane, aminophenylacetylene and 3, 3', 4, 4' benzophenonetetracarboxylic dianhydride in different molar ratios. The prepolymers were isolated and characterized for melt flow and cure properties. They show promise as adhesives for bonding titanium to titanium and as matrix resins for graphite cloth reinforced composites. The most promising system has been blended in varying proportions with Thermid 600, a commercially available acetylene terminated polyimide oligomer, and the mixtures have been tested for application as composite matrix resins.

A novel metal-organic framework for high storage and separation of acetylene at room temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Xing, E-mail: star1987@hdu.edu.cn; Wang, Huizhen; Ji, Zhenguo

2016-09-15

A novel 3D microporous metal-organic framework with NbO topology, [Cu{sub 2}(L)(H{sub 2}O){sub 2}]∙(DMF){sub 6}·(H{sub 2}O){sub 2} (ZJU-10, ZJU = Zhejiang University; H{sub 4}L =2′-hydroxy-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid; DMF =N,N-dimethylformamide), has been synthesized and structurally characterized. With suitable pore sizes and open Cu{sup 2+} sites, ZJU-10a exhibits high BET surface area of 2392 m{sup 2}/g, as well as moderately high C{sub 2}H{sub 2} volumetric uptake capacity of 132 cm{sup 3}/cm{sup 3}. Meanwhile, ZJU-10a is a promising porous material for separation of acetylene from methane and carbon dioxide gas mixtures at room temperature. - Graphical abstract: A new NbO-type microporous metal-organic framework ZJU-10 withmore » suitable pore size and open Cu{sup 2+} sites was synthesized to realize the strong interaction with acetylene molecules, which can separate the acetylene from methane and carbon dioxane gas mixtures at room temperature. Display Omitted - Highlights: • A novel 3D NbO-type microporous metal-organic framework ZJU-10 was solvothermally synthesized and structurally characterized. • ZJU-10a exhibits high BET surface area of 2392 m{sup 2}/g. • ZJU-10a shows a moderately high C{sub 2}H{sub 2} gravimetric (volumetric) uptake capacity of 174 (132) cm{sup 3}/g at 298 K and 1 bar. • ZJU-10a can separate acetylene from methane and carbon dioxide gas mixtures at room temperature.« less

Sonolysis of hydrocarbons in aqueous solution

NASA Astrophysics Data System (ADS)

Hart, Edwin J.; Fischer, Christian-Herbert; Henglein, Arnim

Water was irradiated with 300 kHz ultrasound under an argon atmosphere containing various amounts of methane and ethane. Limited studies were also made on ethylene, acetylene, propane and butane. The methane and ethane irradiations were carried out over the hydrocarbon-argon range of 2-100%. Maximum decomposition occurs at 15% for methane and 10% for ethane. While hydrogen is a dominant product in both cases, acetylene, ethylene and ethane are prominent products, too. Propane, propene and propin form in lesser quantities. 2-methyl-propane, n-butane, l-butene, 2-methyl-butene, butadiene and n-butin have also been identified. These hydrocarbons are similar to those found in pyrolysis and in fuel rich combustion experiments. Carbon monoxide is an important product at hydrocarbon concentrations less than 40% establishing water was an oxygen delivering reactant under these conditions. In the case of methane, the ratio of ethylene plus acetylene to ethane is used to estimate the effective temperature in the cavitation bubble. A temperature of about 2800 K is obtained for bubbles containing argon (plus water vapor and 20% CH 4) and T = 2000 K for pure methane. The rate of decomposition for unsaturated hydrocarbons is substantially greater than for the saturated ones. Low molecular weight products are mainly formed from saturated hydrocarbons whereas polymerization products are mainly formed from the unsaturated hydrocarbons. The decomposition of acetylene in argon bubbles is one of the fastest sonolytic processes.

Detection of diazotrophy in the acetylene-fermenting anaerobe Pelobacter sp. strain SFB93

USGS Publications Warehouse

Akob, Denise M.; Baesman, Shaun; Sutton, John M.; Fierst, Janna L.; Mumford, Adam; Shrestha, Yesha; Poret-Peterson, Amisha T.; Bennett, Stacy; Dunlap, Darren S.; Haase, Karl B.; Oremland, Ronald S.

2017-01-01

Acetylene (C2H2) is a trace constituent of the present Earth's oxidizing atmosphere, reflecting a mixture of terrestrial and marine emissions from anthropogenic, biomass-burning, and unidentified biogenic sources. Fermentation of acetylene was serendipitously discovered during C2H2 block assays of N2O reductase, and Pelobacter acetylenicus was shown to grow on C2H2 via acetylene hydratase (AH). AH is a W-containing, catabolic, low-redox-potential enzyme that, unlike nitrogenase (N2ase), is specific for acetylene. Acetylene fermentation is a rare metabolic process that is well characterized only in P. acetylenicus DSM3246 and DSM3247 and Pelobacter sp. strain SFB93. To better understand the genetic controls for AH activity, we sequenced the genomes of the three acetylene-fermenting Pelobacter strains. Genome assembly and annotation produced three novel genomes containing gene sequences for AH, with two copies being present in SFB93. In addition, gene sequences for all five compulsory genes for iron-molybdenum N2ase were also present in the three genomes, indicating the cooccurrence of two acetylene transformation pathways. Nitrogen fixation growth assays showed that DSM3426 could ferment acetylene in the absence of ammonium, but no ethylene was produced. However, SFB93 degraded acetylene and, in the absence of ammonium, produced ethylene, indicating an active N2ase. Diazotrophic growth was observed under N2 but not in experimental controls incubated under argon. SFB93 exhibits acetylene fermentation and nitrogen fixation, the only known biochemical mechanisms for acetylene transformation. Our results indicate complex interactions between N2ase and AH and suggest novel evolutionary pathways for these relic enzymes from early Earth to modern days.

Supramolecular binding and separation of hydrocarbons within a functionalized porous metal–organic framework

DOE PAGES

Yang, Sihai; Ramirez-Cuesta, Anibal J.; Newby, Ruth; ...

2014-12-01

Supramolecular interactions are fundamental to host–guest binding in many chemical and biological processes. Direct visualization of such supramolecular interactions within host–guest systems is extremely challenging, but crucial to understanding their function. Within this paper, we report a comprehensive study that combines neutron scattering, synchrotron X-ray and neutron diffraction, and computational modelling to define the detailed binding at a molecular level of acetylene, ethylene and ethane within the porous host NOTT-300. This study reveals simultaneous and cooperative hydrogen-bonding, π···π stacking interactions and intermolecular dipole interactions in the binding of acetylene and ethylene to give up to 12 individual weak supramolecular interactionsmore » aligned within the host to form an optimal geometry for the selective binding of hydrocarbons. In addition, we also report the cooperative binding of a mixture of acetylene and ethylene within the porous host, together with the corresponding breakthrough experiments and analysis of adsorption isotherms of gas mixtures.« less

The kinetics of the reduction of isocyanides, acetylenes and the cyanide ion by nitrogenase preparation from Azotobacter chroococcum and the effects of inhibitors

PubMed Central

Kelly, M.

1968-01-01

1. Nitrogen-fixing preparations from Azotobacter chroococcum reduced substrates with the following Km values: methyl isocyanide, 1·8×10−4m; ethyl isocyanide, 2·5×10−2m; cyanide ion, 1·4×10−3m; acetylene, 1·2×10−4m. 2. Nitrogen, carbon monoxide or hydrogen competitively inhibited isocyanide reduction with the following Ki values: hydrogen, 1·3×10−3m; carbon monoxide, 6·8×10−6m; nitrogen, 4·3×10−4m. 3. Living nitrogen-fixing bacteria, and isolated clover nodules, formed methane from methyl isocyanide. 4. These results are discussed in relation to other work and possible mechanisms of nitrogen fixation. PMID:5642620

Experimental Study of Propulsion Performance by Single-Pulse Rotating Detonation with Gaseous Fuels-Oxygen Mixtures

NASA Astrophysics Data System (ADS)

Toshimitsu, Kazuhiko; Hara, Kosei; Mikajiri, Shuuto; Takiguchi, Naoki

2016-12-01

A rotating detonation engine (RDE) is one of candidates of aerospace engines for supersonic cruse, which is better for propulsion system than a pulse detonation engine (PDE) from the view of continuous thrust and simple structure. The propulsion performance of a proto-type RDE and a PDE by single pulse explosion with methane-oxygen is investigated. Furthermore, the performance of the RDE with acetylene-oxygen gas mixtures is investigated. Its impulse is estimated through ballistic pendulum method with maximum displacement and damping ratio. The comparison of specific impulses of the mixture gases at atmospheric pressure is shown. The specific impulses of the RDE and the PDE are almost same with methane-oxygen gas. Furthermore, the fuel-base specific impulse of the RDE with acetylene-oxygen gas is about over twice as large as one of methane-oxygen, and its maximum specific impulse is 1100 seconds.

Photochemical reactions of cyanoacetylene and dicyanoacetylene: Possible processes in Titan's atmosphere

NASA Technical Reports Server (NTRS)

Ferris, J. P.; Guillemin, J. C.

1991-01-01

Titan has an atmosphere which is subject to dramatic chemical evolution due mainly to the dramatic effect of the UV flux from the Sun. The energetic solar photons and other particles are converting the methane-nitrogen atmosphere into the unsaturated carbon compounds observed by the Voyager probes. These same solar photons are also converting some of these unsaturated reaction products into the aerosols observed in the atmosphere which obscure the view of the surface of Titan. In particular, the photochemical reactions of cyanoacetylene, dicyanoacetylene, acetylene and ethylene may result in the formation of the higher hydrocarbons and polymers which result in the aerosols observed in Titan's atmosphere. Polymers are the principal reaction products formed by irradiation of cyanoacetylene and dicyanoacetylene. Irradiation of cyanoacetylene with 185 nm of light also yields 1,3,5-tricyanobenzene while irradiation at 254 nm yields 1,2,4-tricyanobenzene and tetracyano cyclooctatetraenes. Photolyses of mixtures of cyanoacetylene and acetylene yields mono- and di- cyanobenzenes. The 1-Cyanocyclobutene is formed from the photochemical addition of cyanoacetylene with ethylene. The photolysis of dicyanoacetylene with acetylene yields 2,3-dicyano-1,3-butadiene and 1,2-dicyanobenzene. Tetracyano cyclooctatetraene products were also observed in the photolysis of mixtures of dicyanoacetylene and acetylene with 254 nm light. The 1,2-Dicyano cyclobutene is obtained from the photolysis dicyanoacetylene and ethylene. Reaction mechanisms will be proposed to explain the observed photoproducts.

Mechanism-based inactivation of benzo(a)pyrene hydroxylase by aryl acetylenes and aryl olefins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo(a)pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo(a)pyrene hydroxylase. The mechanism-based loss of benzo(a)pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenesmore » therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, /sup 3/H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo(a)pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne.« less

HCN and chromophore formation on Jupiter

NASA Technical Reports Server (NTRS)

Ferris, James P.; Ishikawa, Yoji

1987-01-01

Reaction paths for the formation of HCN and chromophores on Jupiter are suggested. The reactions involve photolysis of ammonia/acetylene mixtures. Experimental data supporting these pathways are reported.

49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

Code of Federal Regulations, 2010 CFR

2010-10-01

... methyl bromide or methyl chloride mixtures, etc. 173.193 Section 173.193 Transportation Other Regulations... bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. (a) Bromoacetone must be...) Bromoacetone, methyl bromide, chloropicrin and methyl bromide mixtures, chloropicrin and methyl chloride...

Shock tube study of the fuel structure effects on the chemical kinetic mechanisms responsible for soot formation, part 2

NASA Technical Reports Server (NTRS)

Frenklach, M.; Clary, D. W.; Ramachandra, M. K.

1985-01-01

Soot formation in oxidation of allene, 1,3-butadiene, vinylacetylene and chlorobenzene and in pyrolysis of ethylene, vinylacetylene, 1-butene, chlorobenzene, acetylen-hydrogen, benzene-acetylene, benzene-butadiene and chlorobenzene-acetylene argon-diluted mixtures was studied behind reflected shock waves. The results are rationalized within the framework of the conceptual models. It is shown that vinylacetylene is much less sooty than allene, which indicates that conjugation by itself is not a sufficient factor for determining the sooting tendency of a molecule. Structural reactivity in the context of the chemical kinetics is the dominant factor in soot formation. Detailed chemical kinetic modeling of soot formation in pyrolysis of acetylene is reported. The main mass growth was found to proceed through a single dominant route composed of conventional radical reactions. The practically irreversible formation reactions of the fused polycyclic aromatics and the overshoot by hydrogen atom over its equilibrium concentration are the g-driving kinetic forces for soot formation.

[Bibliographical study of Minamata disease].

PubMed

Ishihara, Nobuo

2002-01-01

In 1958, Minamata Disease was suggested to be organic mercury compounds intoxication. This suggestion was based on Hunter and Russel's report on occupational exposure to methylmercury. This report is known to have established the typical symptoms of methyl mercury intoxication. However, it has been widely believed since the official recognition of Minamata Disease (1956) that, at the moment of outbreak, no reports were available on organic mercury formation from inorganic mercury in acetaldehyde production from acetylene, or on organic mercury intoxication among workers in acetaldehyde production from acetylene. However, this was not the case. The formation of organic mercury from inorganic mercury used as a catalyst was reported by Vogt and Nieuwland in 1921. In 1930, Zangger reported several cases of organic mercury intoxication among workers in acetaldehyde production from acetylene. Soon after, Koelsch reported that the cases were methyl- and/or ethylmercury intoxication, and that such cases had been common since 1916. These reports were already available at the time of the Minamata Disease outbreak. However, Zangger's report, the most important of these three was not referred to until 1987, notwithstanding its listing in the references of Kurland et al.. Zangger's report was not referred to not by investigators, but by a lawyer. If these reports had been referred to at the outbreak of Minamata Disease, the number of victims in Minamata would have been minimized, and Minamata Disease in Niigata would have been prevented.

In Situ Analyses of Methane Oxidation Associated with the Roots and Rhizomes of a Bur Reed, Sparganium Eurycarpum, in a Maine Wetland

NASA Technical Reports Server (NTRS)

King, Gary M.

1996-01-01

Methane oxidation associated with the belowground tissues of a common aquatic macrophyte, the burweed Sparganium euryearpum, was assayed in situ by a chamber technique with acetylene or methyl fluoride as a methanotrophic inhibitor at a headspace concentration of 3 to 4%. Acetylene and methyl fluoride inhibited both methane oxidation and peat methanogenesis. However, inhibition of methanogenesis resulted in no obvious short-term effect on methane fluxes. Since neither inhibitor adversely affected plant metabolism and both inhibited methanotrophy equally well, acetylene was employed for routine assays because of its low cost and ease of use. Root-associated methanotrophy consumed a variable but significant fraction of the total potential methane flux; values varied between 1 and 58% (mean +/- standard deviation, 27.0% +/- 6.0%), with no consistent temporal or spatial pattern during late summer. The absolute amount of methane oxidized was not correlated with the total potential methane flux; this suggested that parameters other than methane availability (e.g., oxygen availability) controlled the rates of methane oxidation. Estimates of diffusive methane flux and oxidation at the peat surface indicated that methane emission occurred primarily through aboveground plant tissues; the absolute magnitude of methane oxidation was also greater in association with roots than at the peat surface. However, the relative extent of oxidation was greater at the latter locus.

Heat of Combustion of the Product Formed by the Reaction of Acetylene, Ethylene, and Diborane

NASA Technical Reports Server (NTRS)

Tannenbaum, Stanley

1957-01-01

The net heat of combustion of the product formed by the reaction of diborane with a mixture of acetylene and ethylene was found to be 20,440 +/- 150 Btu per pound for the reaction of liquid fuel to gaseous carbon dioxide, gaseous water, and solid boric oxide. The measurements were made in a Parr oxygen-bomb calorimeter, and the combustion was believed to be 98 percent complete. The estimated net-heat of combustion for complete combustion would therefore be 20,850 +/- 150 Btu per pound.

Difluoromethane, a new and improved inhibitor of methanotrophy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, L.G.; Sasson, C.; Oremland, R.S.

1998-11-01

Difluoromethane (HFC-32; DFM) is compared to acetylene and methyl fluoride as an inhibitor of methanotrophy in cultures and soils. DFM was found to be a reversible inhibitor of CH{sub 4} oxidation by Methylococcus capsulatus (Bath). Consumption of CH{sub 4} in soil was blocked by additions of low levels of DFM (0.03 kPa), and this inhibition was reversed by DFM removal. Although a small quantity of DFM was consumed during these incubations, its remaining concentration was sufficiently elevated to sustain inhibition. Methanogenesis in anaerobic soil slurries, including acetoclastic methanogenesis, was unaffected by levels of DFM which inhibit methanotrophy. Low levels ofmore » DFM (0.03 kPa) also inhibited nitrification and N{sub 2}O production by soils. DFM is proposed as an improved inhibitor of CH{sub 4} oxidation over acetylene and/or methyl fluoride on the basis of its reversibility, its efficacy at low concentrations, its lack of inhibition of methanogenesis, and its low cost.« less

Jupiter's atmospheric composition from the Cassini thermal infrared spectroscopy experiment

NASA Technical Reports Server (NTRS)

Kunde, V. G.; Flasar, F. M.; Jennings, D. E.; Bezard, B.; Strobel, D. F.; Conrath, B. J.; Nixon, C. A.; Bjoraker, G. L.; Romani, P. N.; Achterberg, R. K.;

Fundamental studies of desulfurization processes: reaction of methanethiol on ZnO and Cs/ZnO

NASA Astrophysics Data System (ADS)

Dvorak, Joseph; Jirsak, Tomas; Rodriguez, José A.

2001-05-01

The reaction of methanethiol on ZnO and Cs promoted ZnO surfaces has been studied with synchrotron based photoemission and thermal desorption spectroscopy. On ZnO, methanethiol undergoes selective reaction to produce carbon monoxide (37-58%), methane (23-38%), formaldehyde (12-15%), ethane (1-11%), and a mixture of ethylene and acetylene (3-13%). At low temperatures (<100 K), methanethiol reacts to yield thiolate intermediate bound to Zn 2+ cations. The thiolate is stable to 500 K. Above this temperature, C-S bond cleavage occurs to yield methyl intermediate and atomic S. Carbon is removed from the surface as gaseous products above 500 K, and atomic sulfur remains bound to the zinc sites of the surface. Submonolayer amounts of cesium do not have a significant promotional effect on C-S bond cleavage, whereas Cs multilayers are found to significantly lower the activation barrier for C-S bond cleavage. This study illustrates the chemistry associated with the desulfurization of thiols on a catalytically relevant oxide surface.

Hydrogen atom initiated chemistry. [chemical evolution in planetary atmospheres

NASA Technical Reports Server (NTRS)

Hong, J. H.; Becker, R. S.

1979-01-01

H Atoms have been created by the photolysis of H2S. These then initiated reactions in mixtures involving acetylene-ammonia-water and ethylene-ammonia-water. In the case of the acetylene system, the products consisted of two amino acids, ethylene and a group of primarily cyclic thio-compounds, but no free sulfur. In the case of the ethylene systems, seven amino acids, including an aromatic one, ethane, free sulfur, and a group of solely linear thio-compounds were produced. Total quantum yields for the production of amino acids were about 3 x 10 to the -5th and about 2 x 10 to the -4th with ethylene and acetylene respectively as carbon substrates. Consideration is given of the mechanism for the formation of some of the products and implications regarding planetary atmosphere chemistry, particularly that of Jupiter, are explored.

Study of the dc and 100kHz glow discharges in acetylene-nitrogen mixture by means of optical emission spectroscopy

NASA Astrophysics Data System (ADS)

Jamroz, P.; Zyrnicki, W.

2002-09-01

The dc and 100 kHz low pressure discharges in acetylene-nitrogen mixture have been studied here. Optical emission spectroscopy was used for identification of active plasma components and to determine plasma temperature. Relative concentrations of H, CH and CN were investigated versus experimental conditions by optical actinometry techniques. Emission intensities of N2 and N2^+ normalized to intensity of argon line were also monitored as a function of experimental parameters. The rotational temperatures from the N2^+ B^2Σ_u^+-X^2Σ_g^+ (0-0) and CN B^2Σ^+-X^2Σ^+ (0-0) bands and vibrational temperatures from the CN (B^2Σ^+-X^2Σ^+) and N2 (C^3Pi_u-B^3Pi_g) spectra were determined. Plasma processes and plasma equilibrium state were discussed.

Acetylene Fermentation: Relevance to Primordial Biogeochemistry and the Search for Life in the Outer Solar System

NASA Astrophysics Data System (ADS)

Oremland, R. S.; Baesman, S. M.; Miller, L. G.

2013-12-01

Acetylene is a highly reactive component of planet(oid)s with anoxic, methane-rich atmospheres, such as Jupiter, Saturn, Titan, and perhaps the primordial Earth. Included in this group is Enceladus, although it is not clear if the acetylene detected within its jets by Cassini was formed by photolysis of methane, from thermo-catalysis of organic matter in the orb's interior, or a fragmentation artifact of the mass spectrum of a larger hydrocarbon. Acetylene inhibits many microbial processes (e.g., methanogenesis, methane oxidation, hydrogen metabolism, denitrification) yet a number of anaerobes can use it as a carbon and energy source to support growth. The best studied is Pelobacter acetylenicus, which carries out a two-step reaction involving the enzymes acetylene hydratase and acetaldehyde dismutase. The former, a low potential W-containing enzyme, forms acetaldehyde while the latter produces ethanol and acetate. Metabolism of acetylene by mixed microbial communities (sediments and/or enrichment cultures) produces these intermediates, and when coupled with sulfate-reduction or methanogenesis respectively forms CO2 or an equal mixtures of CO2 plus CH4. It is not inconceivable that such an anaerobic, microbial food chain could exist in the waters beneath the ice cap of Enceladus, Titan, or even in the mesothermal atmospheric regions of the gas giants. Detection of the identified intermediate products of acetylene fermentation, namely acetaldehyde, ethanol, acetate and formate in the atmospheres of these planet(oid)s would constitute evidence for a microbial life signature. This evidence would be strongly reinforced if a stable carbon isotope fractionation was identified as well, whereby the products of acetylene fermentation were enriched in 12C relative to 13C (i.e., had a lighter δ13C signal) when compared to that of the starting acetylene. The most practical target to test this hypothesis would be Enceladus (if the detected acetylene is shown to be a real presence in the jet vapors) owing to the relative ease of sample collection and analysis either in future flybys or lander/collector missions.

CO2-broadening and shift coefficients in the ν3 and ν2 + (ν4 +ν5)+0 bands of acetylene

NASA Astrophysics Data System (ADS)

Lyulin, O. M.; Petrova, T. M.; Solodov, A. M.; Solodov, A. A.; Perevalov, V. I.

2018-03-01

The absorption spectra of the mixture of C2H2 and CO2 at different partial pressures of both gases have been recorded at room temperature in the 3 μm region using the Bruker IFS 125 HR FTIR spectrometer. The multispectrum fitting procedure has been applied to these spectra to recover the broadening and shift parameters of the acetylene spectral lines. The CO2 broadening and pressure induced shift coefficients for 119 lines of the ν3 and ν2 + (ν4 +ν5)+0 bands of acetylene have been derived. The rotational dependence of the values of these coefficients is discussed. The comparison of the obtained coefficients to those published by other authors for the ν1 + ν3 and (ν4 +ν5)+0 bands is performed.

Anthropogenic emissions of nonmethane hydrocarbons in the northeastern United States: Measured seasonal variations from 1992-1996 and 1999-2001

NASA Astrophysics Data System (ADS)

Lee, Ben H.; Munger, J. William; Wofsy, Steven C.; Goldstein, Allen H.

2006-10-01

Harvard Forest, a rural site located in central Massachusetts downwind of major urban-industrial centers, provides an excellent location to observe a typical regional mixture of anthropogenic trace gases. Air that arrives at Harvard Forest from the southwest is affected by emissions from the U.S. east coast urban corridor and may have residual influence from emissions in the upper Ohio Valley and Great Lakes region farther to the west. Because of its relatively long distance from large individual emission sources, pollution plumes reaching the site are a homogenized mixture of regional anthropogenic emissions. Concentrations of C2-C6 hydrocarbons along with CO and NOy were measured nearly continuously from August 1992 through July 1996 and from June 1999 through November 2001. By correlating observed concentrations to acetylene, which is almost solely produced during combustion, we are able to detect seasonal trends in relative emissions for this series of trace gases. Seasonal changes in n-butane and i-butane emissions may largely be influenced by different gasoline formulations in late spring and summer. Shifts in evaporation rates due to the annual temperature cycle could induce a seasonal pattern for n-pentane, i-pentane and n-hexane emissions. Emissions of ethane and propane lack clear seasonality relative to acetylene emissions and also correlate less with acetylene than other gases, indicating that emissions of these two gases are strongly influenced by sources not associated with fuel combustion. Changes in the observed correlations of CO2 and CO relative to acetylene are consistent with published changes in the estimated emissions of CO2 and CO over the past decade, though variability in the observations makes it difficult to precisely quantify these changes.

RAILCAR4 Toxic Industrial Chemical Source Characterization Program (Software User’s Manual)

DTIC Science & Technology

2011-08-01

hydroxide (29%) boron trifluoride sulfur trioxide hydrogen chloride methyl bromide phosphine hydrochloric acid (39%) phosphoryl trichloride arsine...Data for Chlorine Trial 05-RC ...............................20 10 Nitric Acid Thermodynamic Properties...Table 1. TICs Available for RAILCAR Simulations chlorine hydrobromic acid (48%) acetylene tetrabromide ammonia OMPA o-anisidine ammonium

A Conversion of Methyl Ketones into Acetylenes: A Project for a Problem-Oriented or Microscale Organic Chemistry Course.

ERIC Educational Resources Information Center

Silveira, Augustine, Jr.; Orlando, Steven C.

1988-01-01

Describes a process for producing terminal or internal alkynes from ketones. Recommends using the experiment to aid in understanding acid-base strength, enolate anion chemistry, reaction at carbon versus oxygen, use of polar aprotic solvents, and elimination and nucleophilic substitution reactions. (ML)

Demonstration of the Feasibility of High Temperature Bearing Lubrication From Carbonaceous Gases

NASA Technical Reports Server (NTRS)

Blanchet, Thierry A.; Sawyer, W. Gregory

1996-01-01

Research has been conducted on silicon nitride pin-on-disk sliding contacts at temperatures of up to 520 C, and four-ball rolling contacts with silicon nitride balls and 52100 steel or silicon nitride races at 590 C. These tests were conducted in a variety of gaseous environments in order to determine the effects of simulated engine exhaust gas on the carbonaceous gas decomposition lubrication scheme. In rolling tests with steel races and exhaust gas the wear track depth was roughly half that of tests run in nitrogen gas alone. The deposition of lubricous microcrystalline graphitic carbon on the rolling surfaces, generated from the carbon monoxide within the exhaust gas mixture, was verified by microfocused Raman spectroscopy. Ten-fold reductions in rolling wear could be achieved by the exhaust gas atmosphere in cases where water vapor was removed or not present. The exhaust gas mixture alone was not found to provide any lubricating effect on silicon nitride sliding contacts, where the rate of wear greatly exceeds the rate of carbon deposition. Directed admixture of acetylene (as low as 5% of the exhaust gas flow rates), has provided reductions in both wear volume and coefficient of friction by factors of 60X and 20X respectively for sliding contacts during the initial 80 m of sliding distance. Exhaust gas atmosphere with the acetylene admixture provided 65OX reductions in steady state wear rate compared to that measured for sliding contacts in dry N2. Such acetylene admixture also augments the ability of the exhaust gas atmosphere to lubricate high-temperature rolling contacts, with up to 25-fold reductions in wear track depth compared to those measured in the presence of N2 alone. In addition to providing some lubricating benefit itself, an important potential role of the exhaust gas from rich mixtures would be to shield bearings from 02. Such shielding enables surface deposition of lubricous pyrolytic carbon from the acetylene admixture, instead of combustion, rendering feasible the continuously replenished solid lubrication of high-temperature bearing surfaces.

A DOSE-RESPONSE STUDY OF THE TOXICITY OF A MIXTURE OF 7N-METHYL CARBAMATE PESTICIDES IN ADULT, MALE RATS.

EPA Science Inventory

There is scarce knowledge regarding the toxicity of pesticide mixtures, especially mixtures of the anticholinesterase N-methyl carbamates. A mixture study was conducted using 7 N-methyl carbamates (carbaryl, carbofuran, formetanate HCl, methiocarb, methomyl, oxamyl, and propoxur...

Experimental investigation and computational modeling of hot filament diamond chemical vapor deposition

NASA Astrophysics Data System (ADS)

Zumbach, Volker; Schäfer, Jörg; Tobai, Jens; Ridder, Michael; Dreier, Thomas; Schaich, Thomas; Wolfrum, Jürgen; Ruf, Bernhard; Behrendt, Frank; Deutschman, Olaf; Warnatz, Jürgen

1997-10-01

A joint investigation has been undertaken of the gas-phase chemistry taking place in a hot-filament chemical vapor-deposition (HFCVD) process for diamond synthesis on silica surfaces by a detailed comparison of numerical modeling and experimental results. Molecular beam sampling using quadrupole mass spectroscopy and resonance-enhanced multiphoton ionization time of flight mass spectroscopy (REMPI-TOF-MS) has been used to determine absolute concentrations of stable hydrocarbons and radicals. Resulting species of a CH4/H2, a CH4/D2 (both 0.5%/99.5%) and a C2H2/H2 (0.25%/99.75%) feedgas mixture were investigated for varying filament and substrate temperatures. Spatially resolved temperature profiles at various substrate temperatures, obtained from coherent anti-Stokes Raman spectroscopy (CARS) of hydrogen, are used as input parameters for the numerical code to reproduce hydrogen atom, methyl radical, methane, acetylene, and ethylene concentration profiles in the boundary layer of the substrate. In addition, the concentration of vibrationally excited hydrogen is determined by CARS. Results reveal only qualitative agreement between measured data and simulations, concerning concentrations of stable species and radicals probed near the surface, on filament and substrate temperature dependence, respectively. Hydrogen and deuterium experiments show similar behaviour for all species. In the case of CH4 as feedgas the model describes measured concentration profiles of CH3, CH4, and C2H2 qualitatively well. Large differences between model and experiment occur for hydrogen atoms (factor of 2) and C2H4 (factor of 3). For acetylene as feedgas the model is not able to give any predictions because no conversion of C2H2 is seen in the model in contrast to the experiment.

Organic synthesis in experimental impact shocks

NASA Technical Reports Server (NTRS)

McKay, C. P.; Borucki, W. J.

1997-01-01

Laboratory simulations of shocks created with a high-energy laser demonstrate that the efficacy of organic production depends on the molecular, not just the elemental composition of the shocked gas. In a methane-rich mixture that simulates a low-temperature equilibrium mixture of cometary material, hydrogen cyanide and acetylene were produced with yields of 5 x 10(17) molecules per joule. Repeated shocking of the methane-rich mixture produced amine groups, suggesting the possible synthesis of amino acids. No organic molecules were produced in a carbon dioxide-rich mixture, which is at odds with thermodynamic equilibrium approaches to shock chemistry and has implications for the modeling of shock-produced organic molecules on early Earth.

Total synthesis of Ivorenolide A following a base-induced elimination protocol.

PubMed

Mohapatra, Debendra K; Umamaheshwar, Gonela; Rao, R Nageshwar; Rao, T Srinivasa; R, Sudheer Kumar; Yadav, Jhillu S

2015-02-20

A concise and stereocontrolled first total synthesis of Ivorenolide A (1) is reported in 16 longest linear steps with a 13.4% overall yield starting from (+)-diethyl tartrate (DET). Key features are base-induced elimination protocol for the construction of chiral propargyl alcohols in both fragments, Pd-catalyzed cross-coupling of terminal acetylenes, and Shiina's 2-methyl-6-nitrobezoic anhydride (MNBA) mediated macrolactonization.

Optical absorption of carbon and hydrocarbon species from shock heated acetylene and methane in the 135-220 nm wavelength range

NASA Technical Reports Server (NTRS)

Shinn, J. L.

1981-01-01

Absorption spectroscopy of carbon and hydrocarbon species has been performed in a shock tube at an incident shock condition for a wavelength range of 135-220 nm, in order to obtain information needed for calculating radiation blockage ahead of a planetary probe. Instrumentation consisted of high frequency response pressure transducers, thin-film heat transfer gages, or photomultipliers coupled by light pipes. Two test-gas mixtures, one with acetylene and the other with methane, both diluted with argon, were used to provide a reliable variation of C3 and C2H concentration ratio. Comparison of tests results of the two mixtures, in the temperature range of 3750 + or - 100 K, showed the main absorbing species to be C3. The wavelength for maximum absorption agrees well with the theoretical values of 7.68 eV and 8.03 eV for the vertical excitation energy, and a value of 0.90 for the electronic oscillator strength, obtained from the measured absorption band, is also in good agreement with the predicted value of 0.92.

Analysis of Effluent Gases During the CCVD Growth of Multi Wall Carbon Nanotubes from Acetylene

NASA Technical Reports Server (NTRS)

Schmitt, T. C.; Biris, A. S.; Miller, D. W.; Biris, A. R.; Lupu, D.; Trigwell, S.; Rahman, Z. U.

2005-01-01

Catalytic chemical vapor deposition was used to grow multi-walled carbon nanotubes on a Fe:Co:CaCO3 catalyst from acetylene. The influent and effluent gases were analyzed by gas chromatography and mass spectrometry at different time intervals during the nanotubes growth process in order to better understand and optimize the overall reaction. A large number of byproducts were identified and it was found that the number and the level for some of the carbon byproducts significantly increased over time. The CaCO3 catalytic support thermally decomposed into CaO and CO2 resulting in a mixture of two catalysts for growing the nanotubes, which were found to have outer diameters belonging to two main groups 8 to 35 nm and 40 to 60 nm, respectively.

An improved synthesis for the (Z)-14-methyl-9-pentadecenoic acid and its topoisomerase I inhibitory activity

PubMed Central

Carballeira, Néstor M.; Sanabria, David; Oyola, Delise

2006-01-01

An improved synthesis for the (Z)-14-methyl-9-pentadecenoic acid was developed based on the appropriate use of (trimethylsilyl)acetylene as the key reagent in the synthesis. The reported synthesis started with commercially available 8-bromo-1-octanol and furnished the desired acid in seven steps and in a 16% overall yield, a significant improvement over the previous reported synthesis for this fatty acid. The synthesis reported herein afforded sufficient amounts to study the acid topoisomerase I inhibitory potential and it was found that the title acid inhibits the human placenta DNA topoisomerase I enzyme at concentrations of 500 μM. PMID:17680032

A rapid method for determining tin and molybdenum in geological samples by flame atomic-absorption spectroscopy

USGS Publications Warehouse

Welsch, E.P.

1985-01-01

The proposed method uses a lithium metaborate fusion, dissolution of the fusion bead in 15% v v hydrochloric acid, extraction into a 4% solution of trioctylphosphine oxide in methyl isobutyl ketone, and aspiration into a nitrous oxide-acetylene flame. The limits of detection for tin and molybdenum are 1.0 and 0.5 ppm, respectively. Approximately 50 samples can be analysed per day. ?? 1985.

Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s.

PubMed

Miller, Laurence G; Baesman, Shaun M; Oremland, Ronald S

2015-11-01

We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. Acetylene-Fermentation-Isotope fractionation-Enceladus-Life detection.

Modeling internal ballistics of gas combustion guns.

PubMed

Schorge, Volker; Grossjohann, Rico; Schönekess, Holger C; Herbst, Jörg; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias

2016-05-01

Potato guns are popular homemade guns which work on the principle of gas combustion. They are usually constructed for recreational rather than criminal purposes. Yet some serious injuries and fatalities due to these guns are reported. As information on the internal ballistics of homemade gas combustion-powered guns is scarce, it is the aim of this work to provide an experimental model of the internal ballistics of these devices and to investigate their basic physical parameters. A gas combustion gun was constructed with a steel tube as the main component. Gas/air mixtures of acetylene, hydrogen, and ethylene were used as propellants for discharging a 46-mm caliber test projectile. Gas pressure in the combustion chamber was captured with a piezoelectric pressure sensor. Projectile velocity was measured with a ballistic speed measurement system. The maximum gas pressure, the maximum rate of pressure rise, the time parameters of the pressure curve, and the velocity and path of the projectile through the barrel as a function of time were determined according to the pressure-time curve. The maximum gas pressure was measured to be between 1.4 bar (ethylene) and 4.5 bar (acetylene). The highest maximum rate of pressure rise was determined for hydrogen at (dp/dt)max = 607 bar/s. The muzzle energy was calculated to be between 67 J (ethylene) and 204 J (acetylene). To conclude, this work provides basic information on the internal ballistics of homemade gas combustion guns. The risk of injury to the operator or bystanders is high, because accidental explosions of the gun due to the high-pressure rise during combustion of the gas/air mixture may occur.

The Synthesis of Phenyl Acetylene Phenols for Development of New Explosives

NASA Astrophysics Data System (ADS)

Chikhradze, Nikoloz; Nadirashvili, Merab; Khomeriki, Sergo; Varshanidze, Iasha

2017-12-01

The purpose of this research is to produce derivatives of simple phenols as “raw material” for the synthesis of new phenolic explosives. A big number of valuable products is synthesized from phenol and its homologues including well-known explosives - picric acid, methyl picrate, cresolite, etc. In general, a structural modification of well-known explosives’ molecules is the most important among the methods for the synthesis of new explosives. This method can be used in certain modifications. For example, the synthesis of methyl picrate is possible not only to replace picric acid’s hydroxyl with metoxyl, but with nitration of anisole as well, i. e, by the reciprocating synthesis. Thus, to produce the new analogues of well-known phenolic explosives, the preliminary modification of simple phenols’ molecules and further nitration, presumably by a formation of dinitro derivatives may be performed. The alkylation of phenol, anisole and m - cresol by the secondary phenyl acetylene alcohols in the presence of concentrated phosphoric acid was carried out. Para-substituted alkynyl phenols with high yields were developed. The chemical transformations were carried out by a participation of their molecules’ active centres. The corresponding ethers, esters and saturated isologues have been synthesized. The article describes the conditions of a synthesis of 14 new phenyl acetylenes’ substances that may be used as substrates in a nitration reaction.

Correlating the cold flow and melting properties of fatty acid methyl ester (FAME) mixtures

USDA-ARS?s Scientific Manuscript database

Fatty acid methyl ester (FAME) mixtures derived from plant oils or animal fats are used to make biodiesel, lubricants, surfactants, plasticizers, ink solvents, paint strippers and other products. Processing requires a precise knowledge of the physico-chemical properties of mixtures with diverse and ...

Knock-limited performance of several internal coolants

NASA Technical Reports Server (NTRS)

Bellman, Donald R; Evvard, John C

1945-01-01

The effect of internal cooling on the knock-limited performance of an-f-28 fuel was investigated in a CFR engine, and the following internal coolants were used: (1) water, (2), methyl alcohol-water mixture, (3) ammonia-methyl alcohol-water mixture, (4) monomethylamine-water mixture, (5) dimethylamine-water mixture, and (6) trimethylamine-water mixture. Tests were run at inlet-air temperatures of 150 degrees and 250 degrees F. to indicate the temperature sensitivity of the internal-coolant solutions.

Modification of the amorphous carbon films by the ns-laser irradiation

NASA Astrophysics Data System (ADS)

Grigonis, Alfonsas; Marcinauskas, Liutauras; Vinciunaite, Vinga; Raciukaitis, Gediminas

2011-10-01

The effect of a nanosecond laser irradiation of thin (60 and 145 nm) amorphous, diamond-like carbon films deposited on Si substrate by an ion beam deposition (IBD) from pure acetylene and acetylene/hydrogen (1:2) gas mixture was analyzed in this work. The films were irradiated with the infrared (IR) and ultraviolet (UV) radiation of the nanosecond Nd:YAG lasers working at the first (1.16 eV) and the third (3.48 eV) harmonics, using a multi-shot regime. The IR laser irradiation stimulated a minor increase in the fraction of sp2 bonds, causing a slight decrease in the hardness of the films and initiated SiC formation. Irradiation with the UV laser caused the formation of carbides and increased hydrogenization of the Si substrate and the fraction of sp2 sites. Spalliation and ablation were observed at a higher energy density and with a large number of laser pulses per spot.

Aqueous Peroxyoxalate Chemiluminescence.

DTIC Science & Technology

1982-01-01

fluorescence. It should be noted that the chloromethylstyrene, 45, was actually a mixture of the meta and para isomers as received from the supplier...the pentaetWyleneoxy acetylenic derivative, 65. By the conventional scheme, bis-pentaethyleneoxy-BPEA, 66, was obtained as an oil, even after HPLC ...phenylacetylide or lithium amide. The attempted hydrolysis of 56 using NaOH/DMF at reflux gave a semi-solid product, which was not totally pure even after HPLC

Growth of vertically aligned multiwalled carbon nanotubes forests on metal alloy Ni-Nb-N with low content of catalyst

NASA Astrophysics Data System (ADS)

Dubkov, S.; Trifonov, A.; Shaman, Yu; Pavlov, A.; Shulyat'ev, A.; Skorik, S.; Kirilenko, E. P.; Rygalin, B.

2016-08-01

This research shows the possibility of carbon nanotubes (CNTs) formation on the surface of low nickel (∼ 10 at.%) Ni-Nb-N amorphous metal alloy film by CVD method at 550 °C of the gas mixture based on acetylene. The structure of CNT were studied by transmission and scanning-electron microscopy, energy-dispersive X-ray and the Raman spectroscopy.

Two Dimensional Polyamides Prepared From Unsaturated Carboxylic Acids And Amines.

DOEpatents

McDonald, William F.; Huang, Zhi Heng; Wright, Stacy C.; Danzig, Morris; Taylor, Andrew C.

2002-07-17

A polyamide and a process for preparing the polyamide are disclosed. The process comprises reacting in a reaction mixture a monomer selected from unsaturated carboxylic acids, esters of unsaturated carboxylic acids, anhydrides of unsaturated carboxylic acids, and mixtures thereof, and a first amine to form an intermediate reaction product in the reaction mixture, wherein the first amine is selected from RR.sub.1 NH, RNH.sub.2, RR.sub.1 NH.sub.2.sup.+, RNH.sub.3.sup.+ and mixtures thereof, wherein R and R.sub.1 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, and reacting the intermediate reaction product and a second amine to form a polyamide, wherein the second amine is selected from R.sub.2 R.sub.3 NH, R.sub.2 NH.sub.2, R.sub.2 R.sub.3 NH.sub.2.sup.+, R.sub.2 NH.sub.3.sup.+ and mixtures thereof wherein R.sub.2 and R.sub.3 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, wherein multiple of the R, R.sub.1, R.sub.2, and R.sub.3 are in vertically aligned spaced relationship along a backbone formed by the polyamide. In one version of the invention, the monomer is selected from maleic anhydride, maleic acid esters, and mixtures thereof. In another version of the invention, the first amine is an alkylamine, such as tetradecylamine, and the second amine is a polyalkylene polyamine, such as pentaethylenehexamine. In yet another version of the invention, the first amine and the second amine are olefinic or acetylenic amines, such as the reaction products of an alkyldiamine and an acetylenic carboxylic acid. The first amine and the second amine may be the same or different depending on the desired polyamide polymer structure.

Comparative Methylation of 1,8-Dihydroxy-9,10-Anthraquinone: Chemoselectivity in the Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Sereda, Grigori A.

2005-01-01

A study has shown that methylation of 1,8-dihydroxy-9,10-anthraquinone (1) with methyl tosylate is highly dependent upon reaction conditions. When the reaction is carried out by a simple heating of the reaction mixture without solvent it yields dimethyl product in a nearly quantitative yield and refluxing the same mixture of reactants in…

Fabrication and Optimization of Carbon Nanomaterial-Based Lithium-Ion Battery Anodes

DTIC Science & Technology

2012-03-01

preparation setup under the fume hood with NMP solvent, glass pipette with dispenser, and the ball milled powder mixture containing LiFePO4 , acetylene...minutes. ............................................................................. 18 Figure 12. (a) LiFePO4 slurry applied on foil current collector...and (b) LiFePO4 slurry casted with applicator and (c) LiFePO4 casted (From [15])....... 18 Figure 13. MTI disc cutter used to cut individual

Post-Shock Sampling of Shock-Heated Hydrocarbon Fuels

DTIC Science & Technology

2016-07-07

on the ability to measure key hydrocarbon fragments (e.g. ethylene , methane, and acetylene) over a wide range of temperatures and pressures. The...series of experiments was conducted to validate the sampling system results and explore the thermal decomposition of ethylene and methane. Initially, a...1% ethylene /0.1% methane/balance argon fuel mixture was shock-heated to ~960 K – a temperature low enough that no reaction would occur. GC analysis

New synthesis of a stereoisomeric mixture of methyl 12-trishomofarnesoate, a juvenile hormone mimic useful in sericulture by increasing silk production

PubMed Central

MORI, Kenji

2017-01-01

A mixture of (E,Z)-isomers of methyl 12-trishomofarnesoate (methyl 3,7,11-trimethyl-2,6,10-pentadecatrienoate), a juvenile hormone mimic, was synthesized in nine steps (32.6% overall yield) by starting from only four commercially available materials: 2-hexanone, vinylmagnesium bromide, methyl acetoacetate and trimethyl phosphonoacetate. The mimic is useful in increasing the yield of silk by elongating the larval period of the silkworm, Bombyx mori (L.). PMID:29021513

New synthesis of a stereoisomeric mixture of methyl 12-trishomofarnesoate, a juvenile hormone mimic useful in sericulture by increasing silk production.

PubMed

Mori, Kenji

2017-01-01

A mixture of (E,Z)-isomers of methyl 12-trishomofarnesoate (methyl 3,7,11-trimethyl-2,6,10-pentadecatrienoate), a juvenile hormone mimic, was synthesized in nine steps (32.6% overall yield) by starting from only four commercially available materials: 2-hexanone, vinylmagnesium bromide, methyl acetoacetate and trimethyl phosphonoacetate. The mimic is useful in increasing the yield of silk by elongating the larval period of the silkworm, Bombyx mori (L.).

49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

Code of Federal Regulations, 2012 CFR

2012-10-01

... packaged as follows in wooden boxes (4C1, 4C2, 4D or 4F) with inner glass receptacles or tubes in... material. Total amount of liquid in the outer box must not exceed 11 kg (24 pounds). Packagings must... bromide mixtures containing up to 2% chloropicrin must be packaged in 4G fiberboard boxes with inside...

49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

Code of Federal Regulations, 2011 CFR

2011-10-01

... packaged as follows in wooden boxes (4C1, 4C2, 4D or 4F) with inner glass receptacles or tubes in... material. Total amount of liquid in the outer box must not exceed 11 kg (24 pounds). Packagings must... bromide mixtures containing up to 2% chloropicrin must be packaged in 4G fiberboard boxes with inside...

Spontaneous ignition delay characteristics of hydrocarbon fuel-air mixtures

NASA Technical Reports Server (NTRS)

Lefebvre, A. H.; Freeman, W. G.; Cowell, L. H.

1986-01-01

The influence of pressure on the autoignition characteristics of homogeneous mixtures of hydrocarbon fuels in air is examined. Autoignition delay times are measured for propane, ethylene, methane, and acetylene in a continuous flow apparatus featuring a multi-point fuel injector. Results are presented for mixture temperatures from 670K to 1020K, pressures from 1 to 10 atmospheres, equivalence ratios from 0.2 to 0.7, and velocities from 5 to 30 m/s. Delay time is related to pressure, temperature, and fuel concentration by global reaction theory. The results show variations in global activation energy from 25 to 38 kcal/kg-mol, pressure exponents from 0.66 to 1.21, and fuel concentration exponents from 0.19 to 0.75 for the fuels studied. These results are generally in good agreement with previous studies carried out under similar conditions.

Chemistry of the outer planets: Investigations of the chemical nature of the atmosphere of Titan

NASA Technical Reports Server (NTRS)

Scattergood, Thomas W.

1985-01-01

It is clear from the experiments that a variety of complex organic models can be produced by lightning in a Titan-like gas mixture. The dominant products were found to be acetylene and hydrogen cyanide, with smaller amounts of many other species. Any aerosol produced by lightning inititated process will consist of a complex mixture of organic compounds, many of which should easily be identified by pyrolytic gas chromatography. Work will continue to expand the data base of molecules produced by lightning and other processes in order to assist in the design of appropriate analytical instruments for the upcoming Saturn/Titan mission and any other planetary probes.

Experimental study on a comparison of typical premixed combustible gas-air flame propagation in a horizontal rectangular closed duct.

PubMed

Jin, Kaiqiang; Duan, Qiangling; Liew, K M; Peng, Zhongjing; Gong, Liang; Sun, Jinhua

2017-04-05

Research surrounding premixed flame propagation in ducts has a history of more than one hundred years. Most previous studies focus on the tulip flame formation and flame acceleration in pure gas fuel-air flame. However, the premixed natural gas-air flame may show different behaviors and pressure dynamics due to its unique composition. Natural gas, methane and acetylene are chosen here to conduct a comparison study on different flame behaviors and pressure dynamics, and to explore the influence of different compositions on premixed flame dynamics. The characteristics of flame front and pressure dynamics are recorded using high-speed schlieren photography and a pressure transducer, respectively. The results indicate that the compositions of the gas mixture greatly influence flame behaviors and pressure. Acetylene has the fastest flame tip speed and the highest pressure, while natural gas has a faster flame tip speed and higher pressure than methane. The Bychkov theory for predicting the flame skirt motion is verified, and the results indicate that the experimental data coincide well with theory in the case of equivalence ratios close to 1.00. Moreover, the Bychkov theory is able to predict flame skirt motion for acetylene, even outside of the best suitable expansion ratio range of 6

Bacterial oxidation of methyl bromide in Mono Lake, California

USGS Publications Warehouse

Connell, T.L.; Joye, S.B.; Miller, L.G.; Oremland, R.S.

1997-01-01

The oxidation of methyl bromide (MeBr) in the water column of Mono Lake, CA, was studied by measuring the formation of H14CO3 from [14C]MeBr. Potential oxidation was detected throughout the water column, with highest rates occurring in the epilimnion (5-12 m depth). The oxidation of MeBr was eliminated by filter-sterilization, thereby demonstrating the involvement of bacteria. Vertical profiles of MeBr activity differed from those obtained for nitrification and methane oxidation, indicating that MeBr oxidation is not simply a co-oxidation process by either nitrifiers or methanotrophs. Furthermore, specific inhibitors of methane oxidation and/or nitrification (e.g., methyl fluoride, acetylene, allyl sulfide) had no effect upon the rate of MeBr oxidation in live samples. Of a variety of potential electron donors added to Mono Lake water, only trimethylamine resulted in the stimulation of MeBr oxidation. Cumulatively, these results suggest that the oxidation of MeBr in Mono Lake waters is attributable to trimethylamine-degrading methylotrophs. Neither methyl chloride nor methanol inhibited the oxidation of [14C]MeBr in live samples, indicating that these bacteria directly oxidized MeBr rather than the products of MeBr nucleophilic substitution reactions.

Low-temperature phase behavior of fatty acid methyl esters by differential scanning calorimetry (DSC)

USDA-ARS?s Scientific Manuscript database

Fatty acid methyl ester (FAME) mixtures have many uses including biodiesel, lubricants, metal-working fluids, surfactants, polymers, coatings, green solvents and phase-change materials. The physical properties of a FAME mixture depends on the fatty acid concentration (FAC) profile. Some products hav...

Effect of structure and deposition technology on tribological properties of DLC coatings alloyed with VIA group metals

NASA Astrophysics Data System (ADS)

Khrushchov, M.; Levin, I.; Marchenko, E.; Avdyukhina, V.; Petrzhik, M.

2016-07-01

The results of a comprehensive research on atomic structure, phase composition, micromechanical and tribological characteristics of alloyed DLC coatings have been presented. The coatings have been deposited by reactive magnetron sputtering in acetylene-nitrogen gas mixtures of different compositions (a-C:H:Cr), by plasma-assisted chemical vapor deposition in atmospheres of silicone-organic precursor gases (a-C:H:Mo:Si), and by nonreactive magnetron sputtering of a composite target (a-C:H:W).

United States Air Force Summer Research Program 1991. Graduate Student Research Program (GSRP) Reports. Volume 7. Phillips Laboratory, Civil Engineering Laboratory

DTIC Science & Technology

1992-01-09

community and should form an impetus for future work in this rapidly developing field. SUMMARY A powerful experimental technique, that of X-ray...appropriate solar radiation absorption properties must be mixed with the hydrogen. Studies have been made which show the alkali metals to be powerful ...deposition of carbon. The treated substrates were placed in a tube furnace through which an acetylene-hydrogen or propane-hydrogen mixture flowed

Potential Jupiter astmospheric constituents: candidates for the mass spectrometer in the Galileo atmospheric probe

NASA Technical Reports Server (NTRS)

Keane, T. C.; Yuan, F.; Ferris, J. P.

1996-01-01

An array of carbon-hydrogen-nitrogen (CHN) compounds are formed when mixtures of ammonia and acetylene are photolyzed with ultraviolet (UV) light. Some of these compounds, formed in our investigation of pathways for HCN synthesis on Jupiter, have not been encountered previously in observational, theoretical or laboratory photochemical studies. Knowledge of these structures may facilitate the interpretation of the mass spectral data obtained by the Galileo probe as it passed through the atmosphere of Jupiter.

Acetylene as fast food: implications for development of life on anoxic primordial Earth and in the outer solar system.

PubMed

Oremland, Ronald S; Voytek, Mary A

2008-02-01

Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is a potent inhibitor of many key anaerobic microbial processes, including methanogenesis, anaerobic methane oxidation, nitrogen fixation, and hydrogen oxidation. Fermentation of acetylene was discovered approximately 25 years ago, and Pelobacter acetylenicus was shown to grow on acetylene by virtue of acetylene hydratase, which results in the formation of acetaldehyde. Acetaldehyde subsequently dismutates to ethanol and acetate (plus some hydrogen). However, acetylene hydratase is specific for acetylene and does not react with any analogous compounds. We hypothesize that microbes with acetylene hydratase played a key role in the evolution of Earth's early biosphere by exploiting an available source of carbon from the atmosphere and in so doing formed protective niches that allowed for other microbial processes to flourish. Furthermore, the presence of acetylene in the atmosphere of a planet or planetoid could possibly represent evidence for an extraterrestrial anaerobic ecosystem.

Impact of operating conditions on the acetylene contamination in the cathode of proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Zhai, Yunfeng; St-Pierre, Jean

2017-12-01

Realistically, proton exchange membrane fuel cells (PEMFCs) are operated under varying operating conditions that potentially impact the acetylene contamination reactions. In this paper, the effects of the cell operating conditions on the acetylene contamination in PEMFCs are investigated under different current densities and temperatures with different acetylene concentrations in the cathode. Electrochemical impedance spectroscopy is applied during the constant-current operation to analyze the impacts of the operating conditions on the acetylene electrochemical reactions. The experimental results indicate that higher acetylene concentrations, higher current densities and lower cell temperatures decrease the cell performance more. In particular, cathode poisoning becomes more severe at medium cell current densities. The cell cathode potentials at such current densities are not sufficient to completely oxidize the intermediate or sufficiently low to completely reduce the adsorbed acetylene. Based on these investigations, the possible condition-dependent limitations of the acetylene concentration and cell operating voltage are proposed for insight into the acetylene contamination mitigation stratagem. Regarding the barrier conditions, the acetylene reactions change abruptly, and adjusting the cell operation parameters to change the acetylene adsorbate and intermediate accumulation conditions to induce complete oxidation or reduction conditions may mitigate the severe acetylene contamination effects on PEMFCs.

Acetylene as fast food: Implications for development of life on anoxic primordial earth and in the outer solar system

USGS Publications Warehouse

Oremland, R.S.; Voytek, M.A.

2008-01-01

Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is a potent inhibitor of many key anaerobic microbial processes, including methanogenesis, anaerobic methane oxidation, nitrogen fixation, and hydrogen oxidation. Fermentation of acetylene was discovered 25 years ago, and Pelobacter acetylenicus was shown to grow on acetylene by virtue of acetylene hydratase, which results in the formation of acetaldehyde. Acetaldehyde subsequently dismutates to ethanol and acetate (plus some hydrogen). However, acetylene hydratase is specific for acetylene and does not react with any analogous compounds. We hypothesize that microbes with acetylene hydratase played a key role in the evolution of Earth's early biosphere by exploiting an available source of carbon from the atmosphere and in so doing formed protective niches that allowed for other microbial processes to flourish. Furthermore, the presence of acetylene in the atmosphere of a planet or planetoid could possibly represent evidence for an extraterrestrial anaerobic ecosystem. ?? Mary Ann Liebert, Inc.

Solubility of pioglitazone hydrochloride in binary mixtures of polyethylene glycol 400 with ethanol, propylene glycol, N-methyl-2-pyrrolidone, and water at 25 degrees C.

PubMed

Jouyban, Abolghasem; Soltanpour, Shahla

2010-09-01

The solubility of pioglitazone hydrochloride in binary mixtures of polyethylene glycol 400 with ethanol, N-methyl-2-pyrrolidone, propylene glycol, and water at 25 degrees C are reported. The generated data are fitted to the Jouyban-Acree model and the mean relative deviations are 2.6%, 1.5%, 5.8%, and 7.4%, respectively for ethanol, N-methyl-2-pyrrolidone, propylene glycol, and water.

A comparison of two nitrification inhibitors used to measure nitrification rates in estuarine sediments

USGS Publications Warehouse

Caffrey, J.M.; Miller, L.G.

1995-01-01

Nitrification rates were measured using intact sediment cores from South San Francisco Bay and two different nitrification inhibitors: acetylene and methyl fluoride. Sediment oxygen consumption and ammonium and nitrate fluxes were also measured in these cores. Four experiments were conducted in the spring, and one in the fall of 1993. There was no significant difference in nitrification rates measured using the two inhibitors, which suggests that methyl fluoride can be used as an effective inhibitor of nitrification. Nitrification was positively correlated with sediment oxygen consumption and numbers of macrofauna. This suggests that bioturbation by macrofauna is an important control of nitrification rates. Irrigation by the tube-dwelling polychaete, Asychis elongata, which dominates the benthic biomass at this location, appears particularly important. Ammonium fluxes out of the sediment were greatest about one week after the spring bloom, while nitrification peaked about one month later.

Isolation and characterization of fatty acid methyl ester (FAME)-producing Streptomyces sp. S161 from sheep (Ovis aries) faeces.

PubMed

Lu, Y; Wang, J; Deng, Z; Wu, H; Deng, Q; Tan, H; Cao, L

2013-09-01

An actinomycete producing oil-like mixtures was isolated and characterized. The strain was isolated from sheep faeces and identified as Streptomyces sp. S161 based on 16S rRNA gene sequence analysis. The strain showed cellulase and xylanase activities. The (1) H nuclear magnetic resonance (NMR) spectra of the mixtures showed that the mixtures were composed of fatty acid methyl esters (52·5), triglycerides (13·7) and monoglycerides (9·1) (mol.%). Based on the gas chromatography-mass spectrometry (GC-MS) analysis, the fatty acid methyl esters were mainly composed of C14-C16 long-chain fatty acids. The results indicated that Streptomyces sp. S161 could produce fatty acid methyl esters (FAME) directly from starch. To our knowledge, this is the first isolated strain that can produce biodiesel (FAME) directly from starch. © 2013 The Society for Applied Microbiology.

41 CFR 50-204.66 - Acetylene.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (b) The piped systems for the in-plant transfer and distribution of acetylene shall be designed..., Vapors, Fumes, Dusts, and Mists § 50-204.66 Acetylene. (a) The in-plant transfer, handling, storage, and...) Plants for the generation of acetylene and the charging (filling) of acetylene cylinders shall be...

Properties of acetylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavlovcak, J.T.

1994-12-31

Acetylene continues to be the most widely used fuel in the oxyfuel cutting and welding industry. It displays properties that enhance its benefits to the industry, but at the same time, present potential hazards that have to be addressed. The presentation explores the main properties or characteristics of acetylene -- odor, toxicity, flammability, composition, and manufacture. it expands on those properties that are unique to acetylene and which account for its main value to the user or which constitute the chief concern for safe use of acetylene. The presentation explains characteristics such as anosmia, flammable or explosive range, ignition energy,more » autoignition temperature, and flame temperature, comparing these values for acetylene to other common gaseous fuels. it explains the unique property of acetylene to decompose explosively in the absence of air or oxygen. The toxicological aspects of acetylene is discussed, including anesthetic effect and simple asphyxiant, showing the increasing severity of symptoms to increasing levels of oxygen deficiency. The main value of this basic review of the properties of acetylene is to remind people of the benefits of acetylene due to its unique properties, and to realert them to the potential hazards that also have to be addressed to control the properties of acetylene.« less

Flammability Characteristics of Fiber-Reinforced Composite Materials for the Composite Infantry Fighting Vehicle

DTIC Science & Technology

1990-09-01

Comments MTL-1 SZIPolyester 70/30 E-701 Baseline MTL-2 S2IPdyester’ 70130 Owens - Corning MTL-3 S2/Polyester* 70/30 American-Cyanamide MTL-5 S2IPhenolic...80120 Owens - Corning *Resin formulation is ro rietary t ~ e s i n is 50150 phenofc-FvB. ’ Organic polymers a re one of the major constituents of...SPECTROMETRY OF MTL-2, OWENS - CORNING ; 900°C IN HELIUM Peak No. Identification Carbon Monoxide and Carbon Dioxide Formaldehyde Propene 1.2-Propadiene 1

Synthesis of Anomeric Methyl Fructofuranosides and Their Separation on an Ion-Exchange Resin

ERIC Educational Resources Information Center

Nurminen, Erkki; Poijarvi, Paivi; Koskua, Katja; Hovinen, Jari

2007-01-01

Treatment of d-fructose with methanol in the presence of acid as a catalyst gives a mixture of methyl-[beta]-d-fructopyranoside, methyl-[alpha]-D-fructofuranoside, and methyl-[beta]-d-fructofuranoside, which were separated on an ion exchange column and characterized polarimetrically.

Surface tension of binary mixtures of water + N-methyldiethanolamine and ternary mixtures of this amine and water with monoethanolamine, diethanolamine, and 2-amino-2-methyl-1-propanol from 25 to 50 C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alvarez, E.; Rendo, R.; Sanjurjo, B.

1998-11-01

The surface tension of aqueous solutions of N-methyldiethanolamine and diethanolamine + N-methyldiethanolamine, monoethanolamine + N-methyldiethanolamine and 2-amino-2-methyl-1-propanol + N-methyldiethanolamine was measured at temperatures from 25 C to 50 C. For binary mixtures the concentration range was 0--50 mass % N-methyldiethanolamine, and for the tertiary mixtures the concentration range for each amine was 0--50 mass %. The experimental values were correlated with temperature and mole fraction. The maximum deviation in both cases was always less than 0.5%.

Viscosity of nonelectrolyte liquid mixtures. III Binary mixtures of methyl methacrylate with hydrocarbons, haloalkanes, and alkylamines

NASA Astrophysics Data System (ADS)

Oswal, S. L.; Patel, B. M.; Shah, H. R.; Oswal, P.

1994-07-01

Measurements of the viscosity η and the density ϱ are reported for 14 binary mixtures of methyl methacrylate (MMA) with hydrocarbons, haloalkanes, and alkylamines at 303.15 K. The viscosity data have been correlated with equations of Grunberg and Nissan, of McAllister, and of Auslaender. Furthermore, excess viscosity Δ In η and excess Gibbs energy of activation ΔG* E of viscous flow have been calculated and have been used to predict molecular interactions occurring in present binary mixtures. The results show the existence of specific interactions in MMA + aromatic hydrocarbons, MMA + haloalkanes, and MMA + primary amines.

An optimized library for reference-based deconvolution of whole-blood biospecimens assayed using the Illumina HumanMethylationEPIC BeadArray.

PubMed

Salas, Lucas A; Koestler, Devin C; Butler, Rondi A; Hansen, Helen M; Wiencke, John K; Kelsey, Karl T; Christensen, Brock C

2018-05-29

Genome-wide methylation arrays are powerful tools for assessing cell composition of complex mixtures. We compare three approaches to select reference libraries for deconvoluting neutrophil, monocyte, B-lymphocyte, natural killer, and CD4+ and CD8+ T-cell fractions based on blood-derived DNA methylation signatures assayed using the Illumina HumanMethylationEPIC array. The IDOL algorithm identifies a library of 450 CpGs, resulting in an average R 2  = 99.2 across cell types when applied to EPIC methylation data collected on artificial mixtures constructed from the above cell types. Of the 450 CpGs, 69% are unique to EPIC. This library has the potential to reduce unintended technical differences across array platforms.

Highly selective condensation of biomass-derived methyl ketones as a source of aviation fuel.

PubMed

Sacia, Eric R; Balakrishnan, Madhesan; Deaner, Matthew H; Goulas, Konstantinos A; Toste, F Dean; Bell, Alexis T

2015-05-22

Aviation fuel (i.e., jet fuel) requires a mixture of C9 -C16 hydrocarbons having both a high energy density and a low freezing point. While jet fuel is currently produced from petroleum, increasing concern with the release of CO2 into the atmosphere from the combustion of petroleum-based fuels has led to policy changes mandating the inclusion of biomass-based fuels into the fuel pool. Here we report a novel way to produce a mixture of branched cyclohexane derivatives in very high yield (>94 %) that match or exceed many required properties of jet fuel. As starting materials, we use a mixture of n-alkyl methyl ketones and their derivatives obtained from biomass. These synthons are condensed into trimers via base-catalyzed aldol condensation and Michael addition. Hydrodeoxygenation of these products yields mixtures of C12 -C21 branched, cyclic alkanes. Using models for predicting the carbon number distribution obtained from a mixture of n-alkyl methyl ketones and for predicting the boiling point distribution of the final mixture of cyclic alkanes, we show that it is possible to define the mixture of synthons that will closely reproduce the distillation curve of traditional jet fuel. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermodynamic equilibrium calculations of dimethyl ether steam reforming and dimethyl ether hydrolysis

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.

The production of a hydrogen-rich fuel-cell feed by dimethyl ether (DME) steam reforming was investigated using calculations of thermodynamic equilibrium as a function of steam-to-carbon ratio (0.00-4.00), temperature (100-600 °C), pressure (1-5 atm), and product species. Species considered were acetone, acetylene, carbon dioxide, carbon monoxide, dimethyl ether, ethane, ethanol, ethylene, formaldehyde, formic acid, hydrogen, isopropanol, methane, methanol, methyl-ethyl ether, n-propanol and water. Thermodynamic equilibrium calculations of DME steam reforming indicate complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide at temperatures greater than 200 °C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure ( P = 1 atm). Increasing the operating pressure shifts the equilibrium toward the reactants; increasing the pressure from 1 to 5 atm decreases the conversion of dimethyl ether from 99.5 to 76.2%. The trend of thermodynamically stable products in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol-formaldehyde, formic acid, and acetylene were not observed. Based on the equilibrium calculations, the optimal processing conditions for dimethyl ether steam reforming occur at a steam-to-carbon ratio of 1.50, a pressure of 1 atm, and a temperature of 200 °C. These thermodynamic equilibrium calculations show dimethyl ether processed with steam will produce hydrogen-rich fuel-cell feeds—with hydrogen concentrations exceeding 70%. The conversion of dimethyl ether via hydrolysis (considering methanol as the only product) is limited by thermodynamic equilibrium. Equilibrium conversion increases with temperature and steam-to-carbon ratio. A maximum dimethyl ether conversion of 62% is achieved at a steam-to-carbon ratio of 5.00 and a processing temperature of 600 °C.

Measurements of acetylene in air extracted from polar ice cores

NASA Astrophysics Data System (ADS)

Nicewonger, M. R.; Aydin, M.; Montzka, S. A.; Saltzman, E. S.

2016-12-01

Acetylene (ethyne) is a non-methane hydrocarbon emitted during combustion of fossil fuels, biofuels, and biomass. The major atmospheric loss pathway of acetylene is oxidation by hydroxyl radical with a lifetime estimated at roughly two weeks. The mean annual acetylene levels over Greenland and Antarctica are 250 ppt and 20 ppt, respectively. Firn air measurements suggest atmospheric acetylene is preserved unaltered in polar snow and firn. Atmospheric reconstructions based on firn air measurements indicate acetylene levels rose significantly during the twentieth century, peaked near 1980, then declined to modern day levels. This historical trend is similar to that of other fossil fuel-derived non-methane hydrocarbons. In the preindustrial atmosphere, acetylene levels should primarily reflect emissions from biomass burning. In this study, we present the first measurements of acetylene in preindustrial air extracted from polar ice cores. Air from fluid and dry-drilled ice cores from Summit, Greenland and WAIS-Divide Antarctica is extracted using a wet-extraction technique. The ice core air is analyzed using gas chromatography and high-resolution mass spectrometry. Between 1400 to 1800 C.E., acetylene levels over Greenland and Antarctica varied between roughly 70-120 ppt and 10-30 ppt, respectively. The preindustrial Greenland acetylene levels are significantly lower than modern levels, reflecting the importance of northern hemisphere fossil fuel sources today. The preindustrial Antarctic acetylene levels are comparable to modern day levels, indicating similar emissions in the preindustrial atmosphere, likely from biomass burning. The implications of the preindustrial atmospheric acetylene records from both hemispheres will be discussed.

PLEMT: A NOVEL PSEUDOLIKELIHOOD BASED EM TEST FOR HOMOGENEITY IN GENERALIZED EXPONENTIAL TILT MIXTURE MODELS.

PubMed

Hong, Chuan; Chen, Yong; Ning, Yang; Wang, Shuang; Wu, Hao; Carroll, Raymond J

2017-01-01

Motivated by analyses of DNA methylation data, we propose a semiparametric mixture model, namely the generalized exponential tilt mixture model, to account for heterogeneity between differentially methylated and non-differentially methylated subjects in the cancer group, and capture the differences in higher order moments (e.g. mean and variance) between subjects in cancer and normal groups. A pairwise pseudolikelihood is constructed to eliminate the unknown nuisance function. To circumvent boundary and non-identifiability problems as in parametric mixture models, we modify the pseudolikelihood by adding a penalty function. In addition, the test with simple asymptotic distribution has computational advantages compared with permutation-based test for high-dimensional genetic or epigenetic data. We propose a pseudolikelihood based expectation-maximization test, and show the proposed test follows a simple chi-squared limiting distribution. Simulation studies show that the proposed test controls Type I errors well and has better power compared to several current tests. In particular, the proposed test outperforms the commonly used tests under all simulation settings considered, especially when there are variance differences between two groups. The proposed test is applied to a real data set to identify differentially methylated sites between ovarian cancer subjects and normal subjects.

Acetylenotrophy: A hidden but ubiquitous microbial metabolism?

USGS Publications Warehouse

Akob, Denise M.; Sutton, John M.; Fierst, Janna L.; Haase, Karl B.; Baesman, Shaun; Luther, George; Miller, Laurence G.; Oremland, Ronald S.

2018-01-01

Acetylene (IUPAC name: ethyne) is a colorless, gaseous hydrocarbon, composed of two triple bonded carbon atoms attached to hydrogens (C2H2). When microbiologists and biogeochemists think of acetylene, they immediately think of its use as an inhibitory compound of certain microbial processes and a tracer for nitrogen fixation. However, what is less widely known is that anaerobic and aerobic microorganisms can degrade acetylene, using it as a sole carbon and energy source and providing the basis of a microbial food web. Here, we review what is known about acetylene degrading organisms and introduce the term 'acetylenotrophs' to refer to the microorganisms that carry out this metabolic pathway. In addition, we review the known environmental sources of acetylene and postulate the presence of an hidden acetylene cycle. The abundance of bacteria capable of using acetylene and other alkynes as an energy and carbon source suggests that there are energy cycles present in the environment that are driven by acetylene and alkyne production and consumption that are isolated from atmospheric exchange. Acetylenotrophs may have developed to leverage the relatively high concentrations of acetylene in the pre-Cambrian atmosphere, evolving later to survive in specialized niches where acetylene and other alkynes were produced.

Laser-Induced Incandescence Measurements in Low Gravity

NASA Technical Reports Server (NTRS)

VanderWal, R. L.

1997-01-01

A low-gravity environment offers advantages to investigations concerned with soot growth or flame radiation by eliminating of buoyancy-induced convection. Basic to each type of study is knowledge of spatially resolved soot volume fraction, (f(sub v). Laser-induced incandescence (LII) has emerged as a diagnostic for soot volume fraction determination because it possesses high temporal and spatial resolution, geometric versatility and high sensitivity. Implementation and system characterization of LII in a drop tower that provides 2.2 sec of low-gravity (micro)g) at the NASA Lewis Research Center are described here. Validation of LII for soot volume fraction determination in (micro)g is performed by comparison between soot volume fraction measurements obtained by light extinction [20] and LII in low-gravity for a 50/50 mixture (by volume) of 0 acetylene/nitrogen issuing into quiescent air. Quantitative soot volume fraction measurements within other laminar flames of ethane and propane and a turbulent diffusion flame in (micro)g via LII are also demonstrated. An analysis of LII images of a turbulent acetylene diffusion flame in 1-g and (micro)g is presented.

Morphology and phase identification of synthesized precipitated calcium carbonate from acetylene gas industry waste

NASA Astrophysics Data System (ADS)

Sabri, Siti Noorzidah Mohd; Othman, Rohaya; Othman, Anuar

2017-12-01

Precipitated calcium carbonate (PCC) is also known as synthetic calcium carbonate. In this paper, PCC was synthesized from carbide lime, which is the by-product from acetylene gas industry. The method used to produce PCC from carbide lime waste was ionic sucrose precipitation technique. The experiments were performed by varying the stirring rate. In this technique, carbide lime was first dissolved in ionic sucrose solution and then chilled at 10 °C for 24 hours before carbon dioxide gasses was introduced into the solution. The carbonation and precipitation process was took place and PCC was formed. The PCC was further filtered to obtain the solid PCC. The sample was then further characterised by using FESEM and XRD to determine the morphology and to identify the phase that exists in the synthesized compound respectively. The XRD and FESEM results clearly shown that the PCC obtained has mixed phases of calcite and vaterite, with mixtures of spherical and irregular shape morphologies formed. The irregular shapes corresponded to vaterite formation, meanwhile spherical shapes corresponded to calcite formation.

Electrical properties of binary mixtures of amino silicone oil and methyl iso butyl ketone

NASA Astrophysics Data System (ADS)

Shah, K. N.; Rana, V. A.; Vankar, H. P.

2018-05-01

The real and imaginary parts of the dielectric function of the binary mixtures of the methyl iso butyl ketone and amino silicone oil in the frequency range 100 Hz to 2 MHz were measured using precision LCR meter at 305.15 K. The electrical properties such as electrical modulus M*(ω), electrical conductivity σ*(ω) and complex impedance Z*(ω) were calculated using the dielectric function ɛ*(ω). The ionic polarization relaxation time (Τσ) and D.C. conductivity (σdc) were also calculated using electrical properties. The ionic behavior of methyl iso butyl ketone and non-ionic behavior of amino silicone oil are also explained. The electrical parameters are used to gain information about the effect of concentration variation of components of the mixtures on the electrical properties.

Siloxane containing addition polyimides

NASA Technical Reports Server (NTRS)

Maudgal, S.; St. Clair, T. L.

1984-01-01

Addition polyimide oligomers have been synthesized from bis(gamma-aminopropyl) tetramethyldisiloxane and 3, 3', 4, 4'-benzophenonetetracarboxylic dianhydride using a variety of latent crosslinking groups as endcappers. The prepolymers were isolated and characterized for solubility (in amide, chlorinated and ether solvents), melt flow and cure properties. The most promising systems, maleimide and acetylene terminated prepolymers, were selected for detailed study. Graphite cloth reinforced composites were prepared and properties compared with those of graphite/Kerimid 601, a commercially available bismaleimide. Mixtures of the maleimide terminated system with Kerimid 601, in varying proportions, were also studied.

Reducing of internal resistance lithium ion battery using glucose addition

NASA Astrophysics Data System (ADS)

Salim, Andri Pratama; Hafidlullah, Noor; Purwanto, Agus

2016-02-01

There are two indicators of battery performance, i.e : capacity and the internal resistance of battery. In this research, the affect of glucose addition to decrease the internal resistance of lithium battery was investigated. The ratio of glucose addition were varied at weight ratio 1%, 3%, and 5% and one mixtures without glucose addition. Lithium ferri phosphate (LiFePO4), polyvinylidene fluoride (PVDF), acetylene black (AB) and glucose were materials that used in this study. Both of mixtures were mixed in the vacuum mixer until became homogeneous. The slurry was coated on an aluminium foil sheet and the coated thickness was 200 µm. The performance of battery lithium was examined by Eight Channel Battery Analyzer and the Internal resistance was examined by Internal Resistance of Battery Meter. The result from all analyzer were showed that the internal resistance reduced as well as the battery capacity. The best internal resistance value is owned by mixtures with 3wt% ratio glucose addition. It has an internal resistance value about 64 miliohm.

Improving cell mixture deconvolution by identifying optimal DNA methylation libraries (IDOL).

PubMed

Koestler, Devin C; Jones, Meaghan J; Usset, Joseph; Christensen, Brock C; Butler, Rondi A; Kobor, Michael S; Wiencke, John K; Kelsey, Karl T

2016-03-08

Confounding due to cellular heterogeneity represents one of the foremost challenges currently facing Epigenome-Wide Association Studies (EWAS). Statistical methods leveraging the tissue-specificity of DNA methylation for deconvoluting the cellular mixture of heterogenous biospecimens offer a promising solution, however the performance of such methods depends entirely on the library of methylation markers being used for deconvolution. Here, we introduce a novel algorithm for Identifying Optimal Libraries (IDOL) that dynamically scans a candidate set of cell-specific methylation markers to find libraries that optimize the accuracy of cell fraction estimates obtained from cell mixture deconvolution. Application of IDOL to training set consisting of samples with both whole-blood DNA methylation data (Illumina HumanMethylation450 BeadArray (HM450)) and flow cytometry measurements of cell composition revealed an optimized library comprised of 300 CpG sites. When compared existing libraries, the library identified by IDOL demonstrated significantly better overall discrimination of the entire immune cell landscape (p = 0.038), and resulted in improved discrimination of 14 out of the 15 pairs of leukocyte subtypes. Estimates of cell composition across the samples in the training set using the IDOL library were highly correlated with their respective flow cytometry measurements, with all cell-specific R (2)>0.99 and root mean square errors (RMSEs) ranging from [0.97 % to 1.33 %] across leukocyte subtypes. Independent validation of the optimized IDOL library using two additional HM450 data sets showed similarly strong prediction performance, with all cell-specific R (2)>0.90 and R M S E<4.00 %. In simulation studies, adjustments for cell composition using the IDOL library resulted in uniformly lower false positive rates compared to competing libraries, while also demonstrating an improved capacity to explain epigenome-wide variation in DNA methylation within two large publicly available HM450 data sets. Despite consisting of half as many CpGs compared to existing libraries for whole blood mixture deconvolution, the optimized IDOL library identified herein resulted in outstanding prediction performance across all considered data sets and demonstrated potential to improve the operating characteristics of EWAS involving adjustments for cell distribution. In addition to providing the EWAS community with an optimized library for whole blood mixture deconvolution, our work establishes a systematic and generalizable framework for the assembly of libraries that improve the accuracy of cell mixture deconvolution.

Effects of gasoline components on MTBE and TBA cometabolism by Mycobacterium austroafricanum JOB5.

PubMed

House, Alan J; Hyman, Michael R

2010-07-01

In this study we have examined the effects of individual gasoline hydrocarbons (C(5-10,12,14) n-alkanes, C(5-8) isoalkanes, alicyclics [cyclopentane and methylcyclopentane] and BTEX compounds [benzene, toluene, ethylbenzene, m-, o-, and p-xylene]) on cometabolism of methyl tertiary butyl ether (MTBE) and tertiary butyl alcohol (TBA) by Mycobacterium austroafricanum JOB5. All of the alkanes tested supported growth and both MTBE and TBA oxidation. Growth on C(5-8) n-alkanes and isoalkanes was inhibited by acetylene whereas growth on longer chain n-alkanes was largely unaffected by this gas. However, oxidation of both MTBE and TBA by resting cells was consistently inhibited by acetylene, irrespective of the alkane used as growth-supporting substrate. A model involving two separate but co-expressed alkane-oxidizing enzyme systems is proposed to account for these observations. Cyclopentane, methylcyclopentane, benzene and ethylbenzene did not support growth but these compounds all inhibited MTBE and TBA oxidation by alkane-grown cells. In the case of benzene, the inhibition was shown to be due to competitive interactions with both MTBE and TBA. Several aromatic compounds (p-xylene > toluene > m-xylene) did support growth and cells previously grown on these substrates also oxidized MTBE and TBA. Low concentrations of toluene (<10 microM) stimulated MTBE and TBA oxidation by alkane-grown cells whereas higher concentrations were inhibitory. The effects of acetylene suggest strain JOB5 also has two distinct toluene-oxidizing activities. These results have been discussed in terms of their impact on our understanding of MTBE and TBA cometabolism and the enzymes involved in these processes in mycobacteria and other bacteria.

Improved Graphite Fiber/Acetylene Terminated Matrix Resin Prepreg Products

DTIC Science & Technology

1988-03-01

AFWAL-TR-80-4151, "The Synthesis of Polymer Precursor and Exploratory Research Based on Acetylene Displacement Reaction," E.T. Sabourin , Gulf...Acetylene Terminated Quinoxalines," E.T. Sabourin , Gulf Research and Development Co., July 1982. ACETYLENE TERMINATED TECHNOLOGY BIBLIOGRAPHY SYNTHESIS AND

Densities and viscosities of solutions of monoethanolamine + N-Methyldiethanolamine + water and monoethanolamine + 2-amino-2-methyl-1-propanol + water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, M.H.; Lie, Y.C.

1994-07-01

The densities and viscosities of aqueous mixtures of monoethanolamine (MEA) with N-methyldiethanolamine (MDEA) and MEA with 2-amino-2-methyl-1-propanol (AMP) have been studied at temperatures from 30 to 80 C. For density measurements, four MEA + MDEA (a total of 20 mass %) + H[sub 2]O mixtures and eight MEA + AMP (20 and 30 mass %) + H[sub 2]O mixtures were studied. For viscosity measurements, ten MEA + MDEA + H[sub 2]O mixtures and eight MEA + AMP + H[sub 2]O mixtures were measured. A Redlich-Kister equation of the excess volume was applied to represent the density of the liquid mixtures.more » The equation of Grunberg and Nissan of liquid viscosity was used to correlate the viscosity data. Both density and viscosity calculations show satisfactory results.« less

Pd-mediated rapid cross-couplings using [(11) C]methyl iodide: groundbreaking labeling methods in (11) C radiochemistry.

PubMed

Doi, Hisashi

2015-03-01

Prof. Bengt Långström is a pioneer in the field of chemistry-driven positron emission tomography (PET) imaging. He has developed a variety of excellent radiolabeling methodologies using the methods of organic chemistry, with the aim of widening the potential of PET in the study of life. Among his groundbreaking achievements in (11) C radiochemistry, there is the discovery of the Pd-mediated rapid cross-coupling reaction using [(11) C]methyl iodide. It was first reported by his Uppsala group in 1994-1995 and was further investigated by his and other groups with a view of enhancing its generality and practicability. This reaction is currently considered one of the basic methods for (11) C-labeling of low-weight organic compounds. This paper presents a short summary of the background and the development of Pd-mediated rapid cross-couplings of [(11) C]methyl iodide, with a focus not only on organostannanes, but also on organoboranes, organozincs, and terminal acetylene compounds. All these reactions have proven to be dependable (11) C-labeling methodologies that use chemically reliable carbon-carbon bond formation reactions. Copyright © 2015 John Wiley & Sons, Ltd.

Design and experimental investigations on six-stroke SI engine using acetylene with water injection.

PubMed

Gupta, Keshav; Suthar, Kishanlal; Jain, Sheetal Kumar; Agarwal, Ghanshyam Das; Nayyar, Ashish

2018-06-02

In the present study, a four-stroke cycle gasoline engine is redesigned and converted into a six-stroke cycle engine and experimental study has been conducted using gasoline and acetylene as fuel with water injection at the end of the recompression stroke. Acetylene has been used as an alternative fuel along with gasoline and performance of the six-stroke spark ignition (SI) engine with these two fuels has been studied separately and compared. Brake power and thermal efficiency are found to be 5.18 and 1.55% higher with acetylene as compared to gasoline in the six-stroke engine. However, thermal efficiency is found to be 45% higher with acetylene in the six-stroke engine as compared to four-stroke SI engine. The CO and HC emissions were found to be reduced by 13.33 and 0.67% respectively with acetylene as compared to gasoline due to better combustion of acetylene. The NO x emission was reduced by 5.65% with acetylene due to lower peak temperature by water injection. The experimental results showed better engine performance and emissions with acetylene as fuel in the six-stroke engine.

Production of low molecular weight hydrocarbons by volcanic eruptions on early Mars.

PubMed

Segura, Antígona; Navarro-González, Rafael

2005-10-01

Methane and other larger hydrocarbons have been proposed as possible greenhouse gases on early Mars. In this work we explore if volcanic processes may have been a source for such molecules based on theoretical and experimental considerations. Geologic evidence and numerical simulations indicate that explosive volcanism was widely distributed throughout Mars. Volcanic lightning is typically produced in such explosive volcanism. Therefore this geologic setting was studied to determine if lightning could be a source for hydrocarbons in volcanic plumes. Volcanic lightning was simulated by focusing a high-energy infrared laser beam inside of a Pyrex reactor that contained the proposed volcanic gas mixture composed of 64% CH(4), 24% H(2), 10% H(2)O and 2% N(2), according to an accretion model and the nitrogen content measured in Martian meteorites. The analysis of products was performed by gas chromatography coupled to infrared and mass spectroscopy. Eleven hydrocarbons were identified among the products, of which acetylene (C(2)H(2)) was the most abundant. A thermochemical model was used to determine which hydrocarbons could arise only from volcanic heat. In this case, acetylene and ethylene are formed at magmatic temperatures. Our results indicate that explosive volcanism may have injected into the atmosphere of early Mars approximately 6 x 10(12) g yr(-1) of acetylene, and approximately 2 x 10(12) g yr(-1) of 1,3-butadiyne, both produced by volcanic lightning, approximately 5 x 10(11) g yr(-1) of ethylene produced by volcanic heat, and 10(13) g yr(-1) of methane.

Partial oxidation of methane by pulsed corona discharges

NASA Astrophysics Data System (ADS)

Hoeben, W. F. L. M.; Boekhoven, W.; Beckers, F. J. C. M.; van Heesch, E. J. M.; Pemen, A. J. M.

2014-09-01

Pulsed corona-induced partial oxidation of methane in humid oxygen or carbon dioxide atmospheres has been investigated for future fuel synthesis applications. The obtained product spectrum is wide, i.e. saturated, unsaturated and oxygen-functional hydrocarbons. The generally observed methane conversion levels are 6-20% at a conversion efficiency of about 100-250 nmol J-1. The main products are ethane, ethylene and acetylene. Higher saturated hydrocarbons up to C6 have been detected. The observed oxygen-functional hydrocarbons are methanol, ethanol and lower concentrations of aldehydes, ketones, dimethylether and methylformate. Methanol seems to be exclusively produced with CH4/O2 mixtures at a maximum production efficiency of 0.35 nmol J-1. CH4/CO2 mixtures appear to yield higher hydrocarbons. Carboxylic acids appear to be mainly present in the aqueous reactor phase, possibly together with higher molecular weight species.

Aviator’s Breathing Oxygen Purity

DTIC Science & Technology

1976-06-01

cocrystallize with acetylene. While solid acetylene will float on UI 1, cocrystals with over 50% nitrous oxide can form a suspension in 7(TZ, and cocrystals with...over 60% nitrous oxide will sink. Cocrystals wR,. over 251" acetylene can detonate (11). Thus, the simultaneous presence of acetylene and nitrous

46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping shall...

46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping shall...

46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping shall...

46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping shall...

46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping shall...

Effect of substrate interaction on the degradation of methyl tert-butyl ether, benzene, toluene, ethylbenzene, and xylene by Rhodococcus sp.

PubMed

Lee, Eun-Hee; Cho, Kyung-Suk

2009-08-15

It was examined the substrate interactions of benzene (B), tolulene (T), ethylbenzene (E), xylene (X), and methyl tert-butyl ether (M) in binary, ternary, quaternary, and quinary mixtures by Rhodococcus sp. EH831 that could aerobically degrade all of five single components. The specific degradation rates (SDRs) of B, T, E, X, and M were 234, 913, 131, 184 and 139 micromol g-dry cell weight (DCW)(-1)h(-1), respectively. In binary, ternary, quaternary, and quinary mixtures of them, ethylbenzene was the strongest inhibitor for the other substrates, and methyl tert-butyl ether was the weakest inhibitor. Interestingly, no degradation of benzene and methyl tert-butyl ether was found in the coexistence of ethylbenzene. The degradation of benzene followed only after toluene became exhausted when both was present. Ethylbenzene was least inhibited by methyl tert-butyl ether and most inhibited by toluene.

Acetylene terminated aspartimides and resins therefrom

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Havens, Stephen J. (Inventor)

1989-01-01

Acetylene terminated aspartimides are prepared using two methods. In the first, an amino-substituted aromatic acetylene is reacted with an aromatic bismaleimide in a solvent of glacial acetic acid and/or m-cresol. In the second method, an aromatic diamine is reacted with an ethynyl containing maleimide, such an N-(3-ethynyl phenyl) maleimide, in a solvent of glacial acetic acid and/or m-cresol. In addition, acetylene terminated aspartimides are blended with various acetylene terminated oligomers and polymers to yield composite materials exhibiting improved mechanical properties.

Dielectric properties of binary mixtures of methyl iso butyl ketone and amino silicone oil

NASA Astrophysics Data System (ADS)

Shah, K. N.; Rana, V. A.; Trivedi, C. M.; Vankar, H. P.

2017-05-01

Dielectric permittivity ɛ*(ω) = ɛ' - jɛ″ of the binary mixtures of the methyl iso butyl ketone and amino silicone oil in the frequency range 100 Hz to 2 MHz were measured using precision LCR meter at 305.15 K. Relative complex permittivity spectra in the frequency range 100 Hz to 2 MHz, of the mixture solutions of varying concentrations is reported. Determined values of the permittivity at optical frequency of all the samples are also reported. The dielectric parameters are used to gain information about the effect of concentration variation of components of the mixtures on the dielectric properties. It also provides the information about electrode polarization phenomena taking place under the low frequency A.C. electric field.

Mixtures For Weed Control in Newly Planted Loblolly Pine (Pinus taeda L.)

Treesearch

J.L. Michael

1987-01-01

Imazapyr, metsulfuron methyl, imazapyr plus metsulfuron methyl, and hexazinone plus metsulfuron methyl were aerially applied over newly planted and 1-year-old loblolly pine seedlings for the control of blackberry (Rubus species), composites (Compositae), sumac (Rhus copallina L.), and trumpet vine [Campsis radicans...

The Stingless Bee Melipona solani Deposits a Signature Mixture and Methyl Oleate to Mark Valuable Food Sources.

PubMed

Alavez-Rosas, David; Malo, Edi A; Guzmán, Miguel A; Sánchez-Guillén, Daniel; Villanueva-Gutiérrez, Rogel; Cruz-López, Leopoldo

2017-10-01

Stingless bees foraging for food improve recruitment by depositing chemical cues on valuable food sites or pheromone marks on vegetation. Using gas chromatography/mass spectrometry and bioassays, we showed that Melipona solani foragers leave a mixture composed mostly of long chain hydrocarbons from their abdominal cuticle plus methyl oleate from the labial gland as a scent mark on rich food sites. The composition of hydrocarbons was highly variable among individuals and varied in proportions, depending on the body part. A wide ratio of compounds present in different body parts of the bees elicited electroantennogram responses from foragers and these responses were dose dependent. Generally, in bioassays, these bees prefer to visit previously visited feeders and feeders marked with extracts from any body part of conspecifics. The mean number of visits to a feeder was enhanced when synthetic methyl oleate was added. We propose that this could be a case of multi-source odor marking, in which hydrocarbons, found in large abundance, act as a signature mixture with attraction enhanced through deposition of methyl oleate, which may indicate a rich food source.

Assessing the long-term variability of acetylene and ethane in the stratosphere of Jupiter

NASA Astrophysics Data System (ADS)

Melin, Henrik; Fletcher, L. N.; Donnelly, P. T.; Greathouse, T. K.; Lacy, J. H.; Orton, G. S.; Giles, R. S.; Sinclair, J. A.; Irwin, P. G. J.

2018-05-01

Acetylene (C2H2) and ethane (C2H6) are both produced in the stratosphere of Jupiter via photolysis of methane (CH4). Despite this common source, the latitudinal distribution of the two species is radically different, with acetylene decreasing in abundance towards the pole, and ethane increasing towards the pole. We present six years of NASA IRTF TEXES mid-infrared observations of the zonally-averaged emission of methane, acetylene and ethane. We confirm that the latitudinal distributions of ethane and acetylene are decoupled, and that this is a persistent feature over multiple years. The acetylene distribution falls off towards the pole, peaking at ∼ 30°N with a volume mixing ratio (VMR) of ∼ 0.8 parts per million (ppm) at 1 mbar and still falling off at ± 70° with a VMR of ∼ 0.3 ppm. The acetylene distributions are asymmetric on average, but as we move from 2013 to 2017, the zonally-averaged abundance becomes more symmetric about the equator. We suggest that both the short term changes in acetylene and its latitudinal asymmetry is driven by changes to the vertical stratospheric mixing, potentially related to propagating wave phenomena. Unlike acetylene, ethane has a symmetric distribution about the equator that increases toward the pole, with a peak mole fraction of ∼ 18 ppm at about ± 50° latitude, with a minimum at the equator of ∼ 10 ppm at 1 mbar. The ethane distribution does not appear to respond to mid-latitude stratospheric mixing in the same way as acetylene, potentially as a result of the vertical gradient of ethane being much shallower than that of acetylene. The equator-to-pole distributions of acetylene and ethane are consistent with acetylene having a shorter lifetime than ethane that is not sensitive to longer advective timescales, but is augmented by short-term dynamics, such as vertical mixing. Conversely, the long lifetime of ethane allows it to be transported to higher latitudes faster than it can be chemically depleted.

How different is the borazine-acetylene dimer from the benzene-acetylene dimer? A matrix isolation infrared and ab initio quantum chemical study

NASA Astrophysics Data System (ADS)

Verma, Kanupriya; Viswanathan, K. S.; Majumder, Moumita; Sathyamurthy, N.

2017-11-01

The 1:1 dimer of borazine-acetylene has been studied for the first time, both experimentally and computationally. The borazine-acetylene dimer was trapped in Ar and N2 matrices, and studied using infrared spectroscopy. Our experiments clearly revealed two isomers of the borazine-acetylene complex, one in which the N-H of borazine interacted with the carbon of acetylene, and another in which the C-H of acetylene formed a hydrogen bond with a nitrogen atom of borazine. The formation of both isomers in the matrix was evidenced by shifts in the vibrational frequencies of the appropriate modes. Reassuringly, the experimental observations were corroborated by our computations using the second-order Møller-Plesset perturbation theoretic method and coupled-cluster singles, doubles and perturbative triples method in conjunction with different Dunning basis sets, which indicated both these isomers to be stable minima, with the N-HṡṡṡC complex being the global minimum. Atoms-in-molecules and energy decomposition analysis were also carried out for the different isomers of the dimer. These studies reveal that replacing the three C-C linkages in benzene with three B-N linkages in borazine modifies the interaction in the dimer sufficiently, to result in a different potential energy landscape for the borazine-acetylene system when compared with the benzene-acetylene system.

Porous anionic indium-organic framework with enhanced gas and vapor adsorption and separation ability.

PubMed

Huang, Yuanbiao; Lin, Zujin; Fu, Hongru; Wang, Fei; Shen, Min; Wang, Xusheng; Cao, Rong

2014-09-01

A three-dimensional microporous anionic metal-organic framework (MOF) (Et4N)3[In3(TATB)4] (FJI-C1, H3TATB=4,4',4''-s-triazine-2,4,6-triyltribenzoic acid) with large unit cell volume has been synthesized. Assisted by the organic cation group Et4N in the pores of the compound, FJI-C1 not only shows high adsorption uptakes of C2 and C3 hydrocarbons, but also exhibits highly selective separation of propane, acetylene, ethane, and ethylene from methane at room temperature. Furthermore, it also exhibits high separation selectivity for propane over C2 hydrocarbons and acetylene can be readily separated from their C2 hydrocarbons mixtures at low pressure due to the high selectivity for C2H2 in comparison to C2H4 and C2H6. In addition, FJI-C1 with hydrophilic internal pores surfaces shows highly efficient adsorption separation of polar molecules from nonpolar molecules. Notably, it exhibits high separation selectivity for benzene over cyclohexane due to the π-π interactions between benzene molecules and s-triazine rings of the porous MOF. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemistry of acetylene on platinum (111) and (100) surfaces

PubMed Central

Muetterties, E. L.; Tasi, M.-C.; Kelemen, S. R.

1981-01-01

An ultra-high vacuum experimental study of acetylene chemisorption on Pt(111) and Pt(100) and of the reaction of hydrogen with the acetylene adsorbate has established distinguishing features of carbon-hydrogen bond breaking and making processes as a function of pressure, temperature, and surface crystallography. The rates for both processes are substantially higher on the Pt(100) surface. Net acetylene-hydrogen processes, in the temperature range of 20°C to ≈130°C, are distinctly different on the two surfaces: on Pt(100) the net reaction is hydrogen exchange (1H-2H exchange) and on Pt(111) the only detectable reaction is hydrogenation. Stereochemical differences in the acetylene adsorbate structure are considered to be a contributing factor to the differences in acetylene chemistry on these two surfaces. Images PMID:16593110

Pathways to Oxygen-Bearing Molecules in the Interstellar Medium and in Planetary Atmospheres: Cyclopropenone (c-C3H2O) and Propynal (HCCCHO)

NASA Astrophysics Data System (ADS)

Zhou, Li; Kaiser, Ralf I.; Gao, Li Gyun; Chang, Agnes H. H.; Liang, Mao-Chang; Yung, Yuk L.

2008-10-01

We investigated the formation of two C3H2O isomers, i.e., cyclopropenone (c-C3H2O) and propynal (HCCCHO), in binary ice mixtures of carbon monoxide (CO) and acetylene (C2H2) at 10 K in an ultrahigh vacuum machine on high-energy electron irradiation. The chemical evolution of the ice samples was followed online and in situ via a Fourier transform infrared spectrometer and a quadrupole mass spectrometer. The temporal profiles of the cyclopropenone and propynal isomers suggest (pseudo-) first-order kinetics. The cyclic structure (c-C3H2O) is formed via an addition of triplet carbon monoxide to ground-state acetylene (or vice versa); propynal (HCCCHO) can be synthesized from a carbon monoxide-acetylene complex via a [HCO...CCH] radical pair inside the matrix cage. These laboratory studies showed for the first time that both C3H2O isomers can be formed in low-temperature ices via nonequilibrium chemistry initiated by energetic electrons as formed in the track of Galactic cosmic ray particles penetrating interstellar icy grains in cold molecular clouds. Our results can explain the hitherto unresolved gas phase abundances of cyclopropenone in star-forming regions via sublimation of c-C3H2O as formed on icy grains in the cold molecular cloud stage. Implications for the heterogeneous oxygen chemistry of Titan and icy terrestrial planets and satellites suggest that the production of oxygen-bearing molecules such as C3H2O may dominate on aerosol particles compared to pure gas phase chemistry.

Computational Screening of MOFs for Acetylene Separation

NASA Astrophysics Data System (ADS)

Nemati Vesali Azar, Ayda; Keskin, Seda

2018-02-01

Efficient separation of acetylene (C2H2) from CO2 and CH4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs) are great candidates for adsorption-based C2H2/CO2 and C2H2/CH4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C2H2/CO2 and C2H2/CH4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C2H2/CO2 and C2H2/CH4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C2H2/CO2 selectivities of 49, 47, 24 and C2H2/CH4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C2H2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4-11 Å, surface areas in the range of 600-1,200 m2/g and porosities between 0.4-0.6 for selective separation of C2H2 from CO2 and CH4. These results will guide the future studies for the design of new MOFs with high C2H2 separation potentials.

A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

EPA Science Inventory

Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

Reducing of internal resistance lithium ion battery using glucose addition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salim, Andri Pratama; Hafidlullah, Noor; Purwanto, Agus, E-mail: aguspurw@gmail.com

There are two indicators of battery performance, i.e : capacity and the internal resistance of battery. In this research, the affect of glucose addition to decrease the internal resistance of lithium battery was investigated. The ratio of glucose addition were varied at weight ratio 1%, 3%, and 5% and one mixtures without glucose addition. Lithium ferri phosphate (LiFePO{sub 4}), polyvinylidene fluoride (PVDF), acetylene black (AB) and glucose were materials that used in this study. Both of mixtures were mixed in the vacuum mixer until became homogeneous. The slurry was coated on an aluminium foil sheet and the coated thickness wasmore » 200 µm. The performance of battery lithium was examined by Eight Channel Battery Analyzer and the Internal resistance was examined by Internal Resistance of Battery Meter. The result from all analyzer were showed that the internal resistance reduced as well as the battery capacity. The best internal resistance value is owned by mixtures with 3wt% ratio glucose addition. It has an internal resistance value about 64 miliohm.« less

Factors that affect molecular weight distribution of Suwannee river fulvic acid as determined by electrospray ionization/mass spectrometry

USGS Publications Warehouse

Rostad, Colleen E.; Leenheer, Jerry A.

2004-01-01

Effects of methylation, molar response, multiple charging, solvents, and positive and negative ionization on molecular weight distributions of aquatic fulvic acid were investigated by electrospray ionization/mass spectrometry. After preliminary analysis by positive and negative modes, samples and mixtures of standards were derivatized by methylation to minimize ionization sites and reanalyzed.Positive ionization was less effective and produced more complex spectra than negative ionization. Ionization in methanol/water produced greater response than in acetonitrile/water. Molar response varied widely for the selected free acid standards when analyzed individually and in a mixture, but after methylation this range decreased. After methylation, the number average molecular weight of the Suwannee River fulvic acid remained the same while the weight average molecular weight decreased. These differences are probably indicative of disaggregation of large aggregated ions during methylation. Since the weight average molecular weight decreased, it is likely that aggregate formation in the fulvic acid was present prior to derivatization, rather than multiple charging in the mass spectra.

Formation of artificial pores in nano-TiO2 photo-electrode films using acetylene-black for high-efficiency, dye-sensitized solar cells

PubMed Central

Cho, Tae-Yeon; Han, Chi-Whan; Jun, Yongseok; Yoon, Soon-Gil

2013-01-01

Acetylene-black paste without a light scattering layer was applied to meso-porous TiO2 photo-electrode films with a crystalline framework, a low residual carbon, and a tunable morphological pore size. The thermal-treated TiO2 photo-electrode films had an increased acetylene-black concentration with an increase in artificial pores and a decrease in residual carbon. The performance of dye-sensitized solar cells (DSSCs) was enhanced by the use of the TiO2 photo-anode pastes at various acetylene-black concentrations. The photo-conversion efficiency of the DSSCs using TiO2 photo-electrode films with 1.5 wt% acetylene-black was enhanced from 7.98 (no acetylene-black) to 9.75% without the integration of a light- scattering layer. PMID:23511122

Titan's atmospheric chemistry: Photolysis of gas mixtures containing hydrogen cyanide and carbon monoxide at 185 and 254 nm

NASA Astrophysics Data System (ADS)

Tran, Buu N.; Force, Michael; Briggs, Robert G.; Ferris, James P.; Persans, Peter; Chera, John J.

2008-01-01

The formation of organic compounds in the atmosphere of Titan is an ongoing process of the generation of complex organics from the simplest hydrocarbon, methane. Solar radiation and magnetosphere electrons are the main energy sources that drive the reactions in Titan's atmosphere. Since energy from solar radiation is 200 times greater than that from magnetosphere electrons, we have investigated the products formed by the action of UV radiation (185 and 254 nm) on a mixture of gases containing nitrogen, methane, hydrogen, acetylene, ethylene, and cyanoacetylene, the basic gas mixture (BGM) that simulates aspects of Titan's atmosphere using a flow reactor [Tran, B.N., Ferris, J.P., Chera, J.J., 2003a. Icarus 162, 114-124; Tran, B.N., Joseph, J.C., Force, M., Briggs, R.G., Vuitton, V., Ferris, J.P., 2005. Icarus 177, 106-115]. The present research extends these studies by the addition of carbon monoxide and hydrogen cyanide to the BGM. Quantum yields for the loss of reactants and the formation of volatile products were determined and compared with those measured in the absence of the hydrogen cyanide and carbon monoxide. The GCMS analyses of the volatile photolysis products from the BGM, with added hydrogen cyanide, had a composition similar to that of the BGM while the photolysis products of the BGM with added carbon monoxide contained many oxygenated compounds. The infrared spectrum of the corresponding solid product revealed the absorption band of a ketone group, which was probably formed from the reaction of carbon monoxide with the free radicals generated by photolysis of acetylene and ethylene. Of particular interest was the observation that the addition of HCN to the gas mixture only resulted in a very small change in the C/N ratio and in the intensity of the C tbnd N frequency at 2210 cm -1 in the infrared spectrum suggesting that little HCN is incorporated into the haze analog. The C/N ratio of the haze analogs was found to be in the 10-12 range. The UV spectra of the solid products formed when HCN or CO added to the BGM is similar to the UV absorption formed from the BGM alone. This result is consistent with absence of additional UV chromophores to the solid product when these mixtures are photolyzed. The following photoproducts, which were not starting materials in our photochemical studies, have been observed on Titan: acetonitrile, benzene, diacetylene, ethane, propene, propane, and propyne.

Dielectric and conformational studies of hydrogen bonded 2-ethoxyethanol and ethyl methyl ketone system

NASA Astrophysics Data System (ADS)

Pattebahadur, Kanchan. L.; Deshmukh, S. D.; Mohod, A. G.; Undre, P. B.; Patil, S. S.; Khirade, P. W.

2018-05-01

The Dielectric constant, density and refractive index of binary mixture of 2-ethoxy ethanol (2-EE) with ethyl methyl ketone (EMK) including those of the pure liquids were measured for 11 concentrations at 25°C temperature. The experimental data is used to calculate the Excess molar volume, Excess dielectric constant, Kirkwood correlation factor and Bruggemann factor. The excess parameters results were fitted to the Redlich-Kister type polynomial equation to derive its fitting coefficient. The Kirkwood correlation factor of the mixture has been discussed to yield information about solute solvent interaction. The Bruggeman plot shows a deviation from linearity. The FT-IR spectra of pure and their binary mixtures are also studied.

Effects of high-melting methyl esters on crystallization properties of fatty acid methyl ester mixtures

USDA-ARS?s Scientific Manuscript database

Biodiesel is a renewable alternative diesel fuel made from vegetable oils and animal fats. The most common form of biodiesel in the United States are fatty acid methyl esters (FAME) from soybean, canola, and used cooking oils, waste greases, and tallow. Cold flow properties of biodiesel depend on th...

Controlled release of sulfasalazine release from "smart" pectin gel microspheres under physiological simulated fluids.

PubMed

Costas, Luciana; Pera, Licia M; López, Azucena Gómez; Mechetti, Magdalena; Castro, Guillermo R

2012-07-01

Sulfasalazine (SLZ) is a synthetic nonsteroidal anti-inflammatory drug used mainly for the treatment of an inflammatory bowel and other diseases. Two pectins with different methylation degrees were blended to synthesized gel microspheres by ionotropic gelation for SLZ encapsulation. The encapsulation efficiency was found to be around of 99% in all formulations tested. However, different SLZ release profiles related to the methylation degrees of pectin were observed. Mixture of low methylated (LM) and high methylated (HM) pectins in the presence of calcium(II) displayed the best microsphere morphologies among the formulations tested determined by optical and electronic microscopies. The percentage of drug release using a mixture of LM and HM pectins after 255 min in simulated gastric fluid (pH = 1.2), simulated intestinal fluid (pH = 6.8), and phosphate buffer (pH = 7.4) were 15.0%, 47.0%, and 52.2%, respectively.

Effect of Temperature on Viscosity of S-Substituted Triazinothiocarbamides in 60% Dioxane Water Mixture

NASA Astrophysics Data System (ADS)

Kshirsagar, A. M.; Tayade, D. T.

2012-10-01

S-triazine and thiocarbamide group containing drug create their own identity in the drug, pharmaceutical and medicinal sciences in last four decades. Hence, the viscometric measurements of recently synthesized drugs viz. 1-(4-hydroxy-6-methyl)-S-triazino-3-phenylthiocarbamide (L1) and 1-(4-hydroxy-6-methyl)-S-triazino-3-methylthiocarbamide (L2), were carried out at 60% various percentage of solvent to investigate effect of structure, on group of S-triazinothiocarbamides. The result obtained during this investigation directly through light on the dipole association of compound, intermolecular attraction between solute and solvent, dielectric constant of medium, polarizability and mutual compensation of dipoles and useful for drug absorption, transmission, stability, activity and effect of drug. %K 1-(4-hydroxy-6-methyl)-S-triazino-3-phenylthiocarbamide (L1) and 1-(4-hydroxy-6-methyl)-S-triazino-3-methylthiocarbamide (L2), dioxane-water mixture, viscometric measurements.

Leukotriene B4 omega-hydroxylase in human polymorphonuclear leukocytes. Suicidal inactivation by acetylenic fatty acids.

PubMed

Shak, S; Reich, N O; Goldstein, I M; Ortiz de Montellano, P R

1985-10-25

Human polymorphonuclear leukocytes (PMN) not only generate and respond to leukotriene B4 (LTB4), but also catabolize this mediator of inflammation rapidly and specifically by omega-oxidation (probably due to the action of a cytochrome P-450 enzyme). To develop pharmacologically useful inhibitors of the LTB4 omega-hydroxylase in human PMN, we devised a general scheme for synthesizing terminal acetylenic fatty acids based on the "acetylenic zipper" reaction. We found that the LTB4 omega-hydroxylase in intact PMN and in PMN sonicates is inactivated in a concentration-dependent fashion by terminal acetylenic analogues of lauric, palmitic, and stearic acids (i.e. 11-dodecynoic, 15-hexadecynoic, and 17-octadecynoic acids). Consistent with a suicidal process, inactivation of the LTB4 omega-hydroxylase requires molecular oxygen and NADPH, is time-dependent, and follows pseudo-first-order kinetics. Inactivation of the omega-hydroxylase by acetylenic fatty acids also is dependent on the terminal acetylenic moiety and the carbon chain length. Saturated fatty acids lacking a terminal acetylenic moiety do not inactivate the omega-hydroxylase. In addition, the two long-chain (C16, C18) acetylenic fatty acids inactivate the omega-hydroxylase at much lower concentrations (less than 5.0 microM) than those required for inactivation by the short-chain (C12) terminal acetylenic fatty acid (100 microM). Potent suicidal inhibitors of the LTB4 omega-hydroxylase in human PMN will help elucidate the roles played by LTB4 and its omega-oxidation products in regulating PMN function and in mediating inflammation.

Selective hydrogenation of acetylene in the presence of ethylene on palladium nanocluster surfaces: A DFT study

NASA Astrophysics Data System (ADS)

Abdollahi, Tahereh; Farmanzadeh, Davood

2018-03-01

In this work, by density functional theory, the palladium nanoclusters were investigated in order to design new catalysts for the selective hydrogenation of acetylene present in olefin feeds. At first, the palladium nanoclusters were studied using PBE-G functional with DNP-ECP basis set. According to the performed calculations, among all the Pdn (n = 2-15) nanoclusters, two Pd12 and Pd2 nanoclusters can be used as catalysts in the reactions of hydrogenation of acetylene and ethylene. The adsorption energy of hydrogen on the Pd12 nanocluster is higher than that of acetylene and ethylene, and therefore, the Pd12 nanocluster is more appropriate for the hydrogenation of acetylene and ethylene. However, the calculated activation energy barriers for the reactions of hydrogenation of acetylene and ethylene showed that the Pd2 nanocluster has more selectivity in comparison to the Pd12 nanocluster. According to our results, the activation energy of the hydrogenation of acetylene to vinyl on the Pd2 nanocluster is 23.96 kJ/mol lower than that on the Pd12 nanocluster. Also, the activation energy of the hydrogenation of ethylene to ethyl on the Pd2 nanocluster is higher than that on the Pd12 nanocluster Therefore, it seems that the Pd2 surface can be used as a catalyst for the selective hydrogenation of acetylene.

Shock tube measurements of the optical absorption of triatomic carbon, C3

NASA Technical Reports Server (NTRS)

Jones, J. J.

1977-01-01

The spectral absorption of C3 has been measured in a shock tube using a test gas mixture of acetylene diluted with argon. The absorption of a pulsed xenon light source was measured by means of eight photomultiplier channels to a spectrograph and an accompanying drum camera. The postshock test gas temperature and pressure were varied over the range 3300-4300 K and 0.36 to 2.13 atmospheres, respectively. The results showed appreciable absorption from C3 for the wavelength range 300 to 540 nanometers. The computed electronic oscillator strength varied from 0.12 to 0.06 as a function of temperature.

29 CFR 1910.102 - Acetylene.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 5 2012-07-01 2012-07-01 false Acetylene. 1910.102 Section 1910.102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Hazardous Materials § 1910.102 Acetylene. (a) Cylinders. Employers...

An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarathy, S M; Thomson, M J; Pitz, W J

2009-12-04

Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents opposed-flow diffusion flame data for one large fatty acid methyl ester, methyl decanoate, and uses the experiments to validate an improved skeletal mechanism consisting of 648 species and 2998 reactions. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.

N-(3-ethynylphenyl)maleimide

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Havens, Stephen J. (Inventor)

1990-01-01

Acetylene terminated aspartimides are prepared using two methods. In the first, an amino-substituted aromatic acetylene is reacted with an aromatic bismaleimide in a solvent of glacial acetic acid and/or m-cresol. In the second method, an aromatic diamine is reacted with an ethynyl containing maleimide, such as N-(3-ethynylphenyl) maleimide, in a solvent of glacial acetic acid and/or m-cresol. In addition, acetylene terminated aspartimides are blended with various acetylene terminated oligomers and polymers to yield composite materials exhibiting improved mechanical properties.

Acetylene as a substrate in the development of primordial bacterial communities

USGS Publications Warehouse

Culbertson, C.W.; Strohmaier, F.E.; Oremland, R.S.

1988-01-01

The fermentation of atmospheric acetylene by anaerobic bacteria is proposed as the basis of a primordial heterotrophic food chain. The accumulation of fermentation products (acetaldehyde, ethanol, acetate and hydrogen) would create niches for sulfate-respiring bacteria as well as methanogens. Formation of acetylene-free environments in soils and sediments would also alter the function of nitrogenase from detoxification to nitrogen-fixation. The possibility of an acetylene-based anaerobic food chain in Jovian-type atmospheres is discussed. ?? 1988 Kluwer Academic Publishers.

Santalbic acid from quandong kernels and oil fed to rats affects kidney and liver P450.

PubMed

Jones, G P; Watson, T G; Sinclair, A J; Birkett, A; Dunt, N; Nair, S S; Tonkin, S Y

1999-09-01

Kernels of the plant Santalum acuminatum (quandong) are eaten as Australian 'bush foods'. They are rich in oil and contain relatively large amounts of the acetylenic fatty acid, santalbic acid (trans-11-octadecen-9-ynoic acid), whose chemical structure is unlike that of normal dietary fatty acids. When rats were fed high fat diets in which oil from quandong kernels supplied 50% of dietary energy, the proportion of santalbic acid absorbed was more than 90%. Feeding quandong oil elevated not only total hepatic cytochrome P450 but also the cytochrome P450 4A subgroup of enzymes as shown by a specific immunoblotting technique. A purified methyl santalbate preparation isolated from quandong oil was fed to rats at 9% of dietary energy for 4 days and this also elevated cytochrome P450 4A in both kidney and liver microsomes in comparison with methyl esters from canola oil. Santalbic acid appears to be metabolized differently from the usual dietary fatty acids and the consumption of oil from quandong kernels may cause perturbations in normal fatty acid biochemistry.

Preparation of reminiscent aroma mixture of Japanese soy sauce.

PubMed

Bonkohara, Kaori; Fuji, Maiko; Nakao, Akito; Igura, Noriyuki; Shimoda, Mitsuya

2016-01-01

To prepare an aroma mixture of Japanese soy sauce by fewest components, the aroma concentrate of good sensory attributes was prepared by polyethylene membrane extraction, which could extract only the volatiles with diethyl ether. GC-MS-Olfactometry was done with the aroma concentrate, and 28 odor-active compounds were detected. Application of aroma extract dilution analysis to the separated fraction revealed high flavor dilution factors with respect to acetic acid, 4-hydroxy-2(or5)-ethyl-5(or2)-methyl-3(2H)-furanone (HEMF), 3-methyl-1-butanol (isoamyl alcohol), and 3-(methylsulfanyl)propanal (methional). A model aroma mixture containing above four odorants showed a good similarity with the aroma of the soy sauce itself. Consequently, the reminiscent aroma mixture of soy sauce was prepared in water. The ratio of acetic acid, HEMF, isoamyl alcohol, and methional was 2500:300:100:1.

Exposure to pesticide mixtures and DNA damage among rice field workers.

PubMed

Varona-Uribe, Marcela Eugenia; Torres-Rey, Carlos H; Díaz-Criollo, Sonia; Palma-Parra, Ruth Marien; Narváez, Diana María; Carmona, Sandra Patricia; Briceño, Leonardo; Idrovo, Alvaro J

2016-01-01

This study describes the use of pesticides mixtures and their potential association with comet assay results in 223 rice field workers in Colombia. Thirty-one pesticides were quantified in blood, serum, and urine (15 organochlorines, 10 organophosphorus, 5 carbamates, and ethylenethiourea), and the comet assay was performed. Twenty-four (77.42%) pesticides were present in the workers. The use of the maximum-likelihood factor analysis identified 8 different mixtures. Afterwards, robust regressions were used to explore associations between the factors identified and the comet assay. Two groups of mixtures--α-benzene hexachloride (α-BHC), hexachlorobenzene (HCB), and β-BHC (β: 1.21, 95% confidence interval [CI]: 0.33-2.10) and pirimiphos-methyl, malathion, bromophos-methyl, and bromophos-ethyl (β: 11.97, 95% CI: 2.34-21.60)--were associated with a higher percentage of DNA damage and comet tail length, respectively. The findings suggest that exposure to pesticides varies greatly among rice field workers.

Use of Water-Fuel Mixture in Diesel Engines at Fishing Vessels

NASA Astrophysics Data System (ADS)

Klyus, Oleg; Bezyukov, O.

2017-06-01

The paper presents the laboratory test results determining physical parameters of fuel mixture made up of petroleum diesel oil, rapeseed oil methyl esters (up to 20%) and water (up to 2.5%). The obtained parameters prove that adding bio-components (rapeseed oil methyl esters) and water to fuel does not result in deterioration of their physical and chemical properties and are comparable to base fuel parameters, namely petroleum diesel oil. The mixture was a subject of bench testing with the use of a self-ignition engine by means of pre-catalytic fuel treatment. The treatment process consisted in fuel - catalytically active material direct contact on the atomizer body. At the comparable operational parameters for the engine, the obtained exhaust gases opacity was lower up to 60% due to the preliminary fuel mixture treatment in relation to the factory-made fuel injection system using petroleum diesel oil.

Flame and flameless atomic-absorption determination of tellurium in geological materials

USGS Publications Warehouse

Chao, T.T.; Sanzolone, R.F.; Hubert, A.E.

1978-01-01

The sample is digested with a solution of hydrobromic acid and bromine and the excess of bromine is expelled. After dilution of the solution to approximately 3 M in hydrobromic acid, ascorbic acid is added to reduce iron(III) before extraction of tellurium into methyl isobutyl ketone (MIBK). An oxidizing air-acetylene flame is used to determine tellurium in the 0.1-20 ppm range. For samples containing 4-200 ppb of tellurium, a carbon-rod atomizer is used after the MIBK extract has been washed with 0.5 M hydrobromic acid to remove the residual iron. The flame procedure is useful for rapid preliminary monitoring, and the flameless procedure can determine tellurium at very low concentrations. ?? 1978.

INTERACTIONS OF CHLORPYRIFOS AND METHYL MERCURY: A MECHANISTIC APPROACH TO ASSESS CHEMICAL MIXTURES

EPA Science Inventory

The mechanism of interaction between chlorpyrifos, an organophosphate insecticide, and methyl mercury was assessed utilizing the amphipod, Hyalella azteca. Previous studies have demonstrated that chlorpyrifos and methl mercury interact additively with survival as the endpoint. I...

Characterization of the Minimum Energy Paths and Energetics for the Reaction of Vinylidene with Acetylene

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Taylor, Peter R.

1995-01-01

The reaction of vinylidene (CH2C) with acetylene may be an initiating reaction in soot formation. We report minimum energy paths and accurate energetics for a pathway leading to vinyl-acetylene and for a number of isomers of C4H4. The calculations use complete active space self-consistent field (CASSCF) derivative methods to characterize the stationary points and internally contacted configuration interaction (ICCI) and/or coupled cluster singles and doubles with a perturbational estimate of triple excitations (CCSD(T)) to determine the energetics. We find an entrance channel barrier of about 5 kcal/mol for the addition of vinylidene to acetylene, but no barriers above reactants for the reaction pathway leading to vinyl-acetylene.

46 CFR 147.70 - Acetylene.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.70 Acetylene. (a) Seventeen cubic meters (600 standard...

46 CFR 147.70 - Acetylene.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.70 Acetylene. (a) Seventeen cubic meters (600 standard...

46 CFR 147.70 - Acetylene.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.70 Acetylene. (a) Seventeen cubic meters (600 standard...

46 CFR 147.70 - Acetylene.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.70 Acetylene. (a) Seventeen cubic meters (600 standard...

46 CFR 147.70 - Acetylene.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.70 Acetylene. (a) Seventeen cubic meters (600 standard...

Complete genome sequence of the acetylene-fermenting Pelobacter sp. strain SFB93

USGS Publications Warehouse

Sutton, John M.; Baesman, Shaun; Fierst, Janna L.; Poret-Peterson, Amisha T.; Oremland, Ronald S.; Dunlap, Darren S.; Akob, Denise M.

2017-01-01

Acetylene fermentation is a rare metabolism that was previously reported as being unique to Pelobacter acetylenicus. Here, we report the genome sequence of Pelobacter sp. strain SFB93, an acetylene-fermenting bacterium isolated from sediments collected in San Francisco Bay, CA.

Factors that affect molecular weight distribution of Suwannee river fulvic acid as determined by electrospray ionization/mass spectrometry

USGS Publications Warehouse

Rostad, C.E.; Leenheer, J.A.

2004-01-01

Effects of methylation, molar response, multiple charging, solvents, and positive and negative ionization on molecular weight distributions of aquatic fulvic acid were investigated by electrospray ionization/mass spectrometry. After preliminary analysis by positive and negative modes, samples and mixtures of standards were derivatized by methylation to minimize ionization sites and reanalyzed.Positive ionization was less effective and produced more complex spectra than negative ionization. Ionization in methanol/water produced greater response than in acetonitrile/water. Molar response varied widely for the selected free acid standards when analyzed individually and in a mixture, but after methylation this range decreased. After methylation, the number average molecular weight of the Suwannee River fulvic acid remained the same while the weight average molecular weight decreased. These differences are probably indicative of disaggregation of large aggregated ions during methylation. Since the weight average molecular weight decreased, it is likely that aggregate formation in the fulvic acid was present prior to derivatization, rather than multiple charging in the mass spectra. ?? 2004 Elsevier B.V. All rights reserved.

Stable carbon isotope fractionation during bacterial acetylene fermentation: Potential for life detection in hydrocarbon-rich volatiles of icy planet(oid)s

USGS Publications Warehouse

Miller, Laurence; Baesman, Shaun; Oremland, Ron

2015-01-01

We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus.

Soot Formation in Hydrocarbon/Air Laminar Jet Diffusion Flames

NASA Technical Reports Server (NTRS)

Sunderland, P. B.; Faeth, G. M.

1994-01-01

Soot processes within hydrocarbon/air diffusion flames are important because they affect the durability and performance of propulsion systems, the hazards of unwanted fires, the pollutant and particulate emissions from combustion processes, and the potential for developing computational combustion. Motivated by these observations, this investigation involved an experimental study of the structure and soot properties of round laminar jet diffusion flames, seeking an improved understanding of soot formation (growth and nucleation) within diffusion flames. The present study extends earlier work in this laboratory concerning laminar smoke points (l) and soot formation in acetylene/air laminar jet diffusion flames (2), emphasizing soot formation in hydrocarbon/air laminar jet diffusion flames for fuels other than acetylene. In the flame system, acetylene is the dominant gas species in the soot formation region and both nucleation and growth were successfully attributed to first-order reactions of acetylene, with nucleation exhibiting an activation energy of 32 kcal/gmol while growth involved negligible activation energy and a collision efficiency of O.53%. In addition, soot growth in the acetylene diffusion flames was comparable to new soot in premixed flame (which also has been attributed to first-order acetylene reactions). In view of this status, a major issue is the nature of soot formation processes in diffusion flame involving hydrocarbon fuels other than acetylene. In particular, information is needed about th dominant gas species in the soot formation region and the impact of gas species other than acetylene on soot nucleation and growth.

Acetylene Fermentation: Relevance to Primordial Biogeochemistry and the Search for Life in the Outer Solar System

NASA Astrophysics Data System (ADS)

Oremland, R. S.; Baesman, S. M.; Miller, L. G.

2014-02-01

Acetylene supports the growth of some terrestrial anaerobes. The reaction is highly exothermic. The abundance of acetylene in the methane-rich planet(oid)s of the outer solar system could represent a means of nourishment for resident alien microbes.

Identification of crystalline structures in jet-cooled acetylene large clusters studied by two-dimensional correlation infrared spectroscopy

NASA Astrophysics Data System (ADS)

Matsumoto, Yoshiteru; Yoshiura, Ryuto; Honma, Kenji

2017-07-01

We investigated the crystalline structures of jet-cooled acetylene (C2H2) large clusters by laser spectroscopy and chemometrics. The CH stretching vibrations of the C2H2 large clusters were observed by infrared (IR) cavity ringdown spectroscopy. The IR spectra of C2H2 clusters were measured under the conditions of various concentrations of C2H2/He mixture gas for supersonic jets. Upon increasing the gas concentration from 1% to 10%, we observed a rapid intensity enhancement for a band in the IR spectra. The strong dependence of the intensity on the gas concentration indicates that the band was assigned to CH stretching vibrations of the large clusters. An analysis of the IR spectra by two-dimensional correlation spectroscopy revealed that the IR absorption due to the C2H2 large cluster is decomposed into two CH stretching vibrations. The vibrational frequencies of the two bands are almost equivalent to the IR absorption of the pure- and poly-crystalline orthorhombic structures in the aerosol particles. The characteristic temperature behavior of the IR spectra implies the existence of the other large cluster, which is discussed in terms of the phase transition of a bulk crystal.

Functionalized Nano and Micro Structured Composite Coatings

DTIC Science & Technology

2011-06-01

created. Contact angles for water, hexadecane and warfare simulants (tributyl phosphate (TBP), methyl salicylate (MS) and 2-chloroethyl ethyl sulfide... methyl salicylate PAA-POEGMA polyacrylic acid-co-poly(oligoethylene glycol methacrylate) PBMA poly(butyl methacrylate) PD-TDES commercial mixture of...polymerized radically (according to a procedure published elsewhere1) to give PGMA, Mn = 300,000 kDa, PDI = 2. The polymerization was carried out in methyl

40 CFR 716.120 - Substances and listed mixtures to which this subpart applies.

Code of Federal Regulations, 2011 CFR

2011-07-01

.../04/82 10/04/92 78-88-6 1-Propene, 2,3-dichloro- 6/1/87 12/19/95 78-93-3 Methyl ethyl ketone—2... Methyl isobutyl ketone—2-Pentanone, 4-methyl- 10/04/82 10/04/92 108-31-6 Maleic anhydride—2,5-Furandione... sunset date. Category CAS No. Special Exemptions Effective Date Sunset Date Aldehydes: Acetaldehyde 75-07...

40 CFR 716.120 - Substances and listed mixtures to which this subpart applies.

Code of Federal Regulations, 2010 CFR

2010-07-01

.../04/82 10/04/92 78-88-6 1-Propene, 2,3-dichloro- 6/1/87 12/19/95 78-93-3 Methyl ethyl ketone—2... Methyl isobutyl ketone—2-Pentanone, 4-methyl- 10/04/82 10/04/92 108-31-6 Maleic anhydride—2,5-Furandione... until the sunset date. Category CAS No. Special Exemptions Effective Date Sunset Date Aldehydes...

40 CFR 716.120 - Substances and listed mixtures to which this subpart applies.

Code of Federal Regulations, 2012 CFR

2012-07-01

.../04/82 10/04/92 78-88-6 1-Propene, 2,3-dichloro- 6/1/87 12/19/95 78-93-3 Methyl ethyl ketone—2... Methyl isobutyl ketone—2-Pentanone, 4-methyl- 10/04/82 10/04/92 108-31-6 Maleic anhydride—2,5-Furandione... sunset date. Category CAS No. Special Exemptions Effective Date Sunset Date Aldehydes: Acetaldehyde 75-07...

40 CFR 716.120 - Substances and listed mixtures to which this subpart applies.

Code of Federal Regulations, 2013 CFR

2013-07-01

.../04/82 10/04/92 78-88-6 1-Propene, 2,3-dichloro- 6/1/87 12/19/95 78-93-3 Methyl ethyl ketone—2... Methyl isobutyl ketone—2-Pentanone, 4-methyl- 10/04/82 10/04/92 108-31-6 Maleic anhydride—2,5-Furandione... sunset date. Category CAS No. Special Exemptions Effective Date Sunset Date Aldehydes: Acetaldehyde 75-07...

40 CFR 716.120 - Substances and listed mixtures to which this subpart applies.

Code of Federal Regulations, 2014 CFR

2014-07-01

.../04/82 10/04/92 78-88-6 1-Propene, 2,3-dichloro- 6/1/87 12/19/95 78-93-3 Methyl ethyl ketone—2... Methyl isobutyl ketone—2-Pentanone, 4-methyl- 10/04/82 10/04/92 108-31-6 Maleic anhydride—2,5-Furandione... until the sunset date. Category CAS No. Special Exemptions Effective Date Sunset Date Aldehydes...

Inhibition of Methanogenesis in Marine Sediments by Acetylene and Ethylene: Validity of the Acetylene Reduction Assay for Anaerobic Microcosms

PubMed Central

Oremland, Ronald S.; Taylor, Barrie F.

1975-01-01

Methanogenesis was irreversibly inhibited in sediments by concentrations of acetylene employed in nitrogen fixation assays (1 to 20%, vol/vol). Ethylene, but not ethane, also stopped methane production, and the inhibition was reversed by gassing with hydrogen. PMID:1190767

Complete genome sequences of two acetylene-fermenting Pelobacter acetylenicus strains

USGS Publications Warehouse

Sutton, John M.; Baesman, Shaun; Fierst, Janna L.; Poret-Peterson, Amisha T.; Oremland, Ronald S.; Dunlap, Darren S.; Akob, Denise M.

2017-01-01

Acetylene fermentation is a rare metabolism that was serendipitously discovered during C2H2-block assays of N2O reductase. Here, we report the genome sequences of two type strains of acetylene-fermenting Pelobacter acetylenicus, the freshwater bacterium DSM 3246 and the estuarine bacterium DSM 3247.

The abundances of ethane and acetylene in the atmospheres of Jupiter and Saturn

NASA Technical Reports Server (NTRS)

Noll, K. S.; Knacke, R. F.; Tokunaga, A. T.; Lacy, J. H.; Beck, S.

1986-01-01

The present determination of the stratospheric abundances of ethane and acetylene on Jupiter and Saturn on the basis of IR spectra near 780/cm uses atmospheric models whose thermal and density profiles have constant mixing ratios. The ratio of ethane to acetylene is noted to be insensitive to model atmosphere assumptions; it is 55 + or - 31 for Jupiter and 23 + or - 12 where model mixing ratios are uniform. Atmospheric model density profiles adapted from theoretical photochemical models are noted to also yield a higher ethane/acetylene ratios for Jupiter.

The abundances of ethane to acetylene in the atmospheres of Jupiter and Saturn

NASA Technical Reports Server (NTRS)

Noll, K. S.; Knacke, R. F.; Tokunaga, A. T.; Lacy, J. H.; Beck, S.; Serabyn, E.

1986-01-01

The present determination of the stratospheric abundances of ethane and acetylene on Jupiter and Saturn on the basis of IR spectra near 780/cm uses atmospheric models whose thermal and density profiles have constant mixing ratios. The ratio of ethane to acetylene is noted to be insensitive to model atmosphere assumptions; it is 55 + or - 31 for Jupiter and 23 + or - 12 where model mixing ratios are uniform. Atmospheric model density profiles adapted from theoretical photochemical models are noted to also yield a higher ethane/acetylene ratios for Jupiter.

KISS: Kinetics and Structure of Superagglomerates Produced by Silane and Acetylene

NASA Technical Reports Server (NTRS)

Mulholland, G. W.; Yang, J. C.; Scott, J. H.; Sivithanu, Y.

2001-01-01

The objective of this study is to understand the process of gas phase agglomeration leading to superagglomerates and a gel-like structure for microgravity (0-g) silane and acetylene flames. Ultimately one would apply this understanding to predicting flame conditions that could lead to the gas phase production of an aero-gel. The approach is to burn acetylene and silane and to analyze the evolution of the soot and silica agglomerates. Acetylene is chosen because it has one of the highest soot volume fractions and there is evidence of super agglomerates being formed in laminar acetylene flames. Silane has the advantage that silica particles are the major combustion product resulting in a particle volume fraction a factor of ten greater than that for a carbonaceous smoke.

Acetylene fermentation: An Earth-based analog of biological carbon cycling on Titan

NASA Astrophysics Data System (ADS)

Miller, L. G.; Baesman, S. M.; Hoeft, S. E.; Kirshtein, J.; Wolf, K.; Voytek, M. A.; Oremland, R. S.

2009-12-01

Acetylene (C2H2) is present in part per million quantities in the atmosphere of Titan; conceivably as an intermediate product of methane photolysis. Currently, Earth’s atmosphere contains only trace amounts of C2H2 (~40 pptv), however higher concentrations likely prevailed during the Hadean and early Archean eons (4.5 - 3.5 Ga). We isolated C2H2-fermenting microbes from various aquatic and sedimentary environments. Acetylene fermentation proceeds via acetylene hydratase (AH) through acetaldehyde, which dismutates to ethanol and acetate, and if oxidants are present (e.g., sulfate) eventually to CO2. Thus, the remnants of a C2H2 cycle exists today on Earth but may also occur on Titan and/or Enceladus, both being planetary bodies hypothesized to have liquid water underlying their frozen surfaces. We developed a molecular method for AH by designing PCR primers to target the functional gene in Pelobacter acetylenicus. We used this method to scan new environments for the presence of AH and we employed DNA sequencing of the 16S rRNA gene in order to positively identify pelobacters in environmental samples. Acetylene fermentation was documented in five diverse salt-, fresh-, and ground-water sites. Pelobacter was identified as the genus responsible for acetylene fermentation in some, but not all, of these sites. Successful probing for AH preceded the discovery of acetylene consumption in a contaminated groundwater site, demonstrating the utility of functional gene probing. A pure culture of a C2H2-fermenting pelobacter was obtained from an intertidal mudflat. We also obtained an enrichment culture (co-cultured with a sulfate reducer) from freshwater lake sediments, but neither was pelobacter nor AH detected in this sample, suggesting that an alternative pathway may be involved here. Slurry experiments using these lake sediments either with or without added C2H2 or sulfate showed that sulfate reduction and acetylene fermentation were independent processes. In general, the ubiquity of acetylene fermentation as well as the presence of AH (an enzyme specific to acetylene) begs the questions; 1) why has this ability persisted on Earth for so long in the absence of significant atmospheric acetylene? 2) does C2H2-fermentation represent a possible means of sustaining growth in the anoxic, aqueous subsurface regions of Titan (and Enceladus)?

Separation of organic azeotropic mixtures by pervaporation. Final technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.W.

1991-12-01

Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simplemore » distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center_dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.« less

Separation of organic azeotropic mixtures by pervaporation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.W.

1991-12-01

Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simplemore » distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.« less

Recognition of the Component Odors in Mixtures

PubMed Central

Fletcher, Dane B; Hettinger, Thomas P

2017-01-01

Abstract Natural olfactory stimuli are volatile-chemical mixtures in which relative perceptual saliencies determine which odor-components are identified. Odor identification also depends on rapid selective adaptation, as shown for 4 odor stimuli in an earlier experimental simulation of natural conditions. Adapt-test pairs of mixtures of water-soluble, distinct odor stimuli with chemical features in common were studied. Identification decreased for adapted components but increased for unadapted mixture-suppressed components, showing compound identities were retained, not degraded to individual molecular features. Four additional odor stimuli, 1 with 2 perceptible odor notes, and an added “water-adapted” control tested whether this finding would generalize to other 4-compound sets. Selective adaptation of mixtures of the compounds (odors): 3 mM benzaldehyde (cherry), 5 mM maltol (caramel), 1 mM guaiacol (smoke), and 4 mM methyl anthranilate (grape-smoke) again reciprocally unmasked odors of mixture-suppressed components in 2-, 3-, and 4-component mixtures with 2 exceptions. The cherry note of “benzaldehyde” (itself) and the shared note of “methyl anthranilate and guaiacol” (together) were more readily identified. The pervasive mixture-component dominance and dynamic perceptual salience may be mediated through peripheral adaptation and central mutual inhibition of neural responses. Originating in individual olfactory receptor variants, it limits odor identification and provides analytic properties for momentary recognition of a few remaining mixture-components. PMID:28641388

Acetylenic carbon allotrope

DOEpatents

Lagow, Richard J.

1998-01-01

A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein.

Acetylenic carbon allotrope

DOEpatents

Lagow, Richard J.

1999-01-01

A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein.

S-alkynyl esters of phosphorus thioacids as inhibitors of cholinesterases and as promising physiologically active compounds

NASA Astrophysics Data System (ADS)

Brestkin, A. P.; Vikhreva, L. A.; Godovikov, Nikolai N.; Zhukovskii, Yu G.; Kabachnik, Martin I.; Moralev, S. N.; Rosengart, V. I.; Sherstobitov, O. E.

1991-08-01

Data are given in the review on the anticholinesterase activity of 58 specially synthesised esters of phosphorus thioacids containing an acetylenic bond in the thioester group. It was established that compounds containing an acetylenic group in the β and especially in the α position of the thioester residue display an inhibitory action many times greater than that of their saturated analogues. A phosphorylated enzyme is formed by the reaction of the acetylenic organophosphorus inhibitors (OPIs) with the enzymes as in the case of reaction with the saturated analogues. It was shown that the acetylenic organophosphorus inhibitors possess high biological activity both for mammals and for arthropods. On replacing the phosphoryl oxygen (P=O) by sulphur (P=S) the toxicity of the acetylenic organophosphorus inhibitors for mammals was sharply reduced but was little changed for arthropods. This raises the possibility of obtaining highly selective insecto-acaricides. The mechanism of the antienzymic action of the acetylenic OPIs and the mechanism of detoxication of diethyl S-hexynyl dithiophosphate are considered. The bibliography includes 44 references.

Molecular Dynamics Simulation Study of the Capacitive Performance of a Binary Mixture of Ionic Liquids near an Onion-like Carbon Electrode.

PubMed

Li, Song; Feng, Guang; Fulvio, Pasquale F; Hillesheim, Patrick C; Liao, Chen; Dai, Sheng; Cummings, Peter T

2012-09-06

An equimolar mixture of 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C3mpy][Tf2N]), 1-methyl-1-butylpiperidinium bis(trifluoromethylsulfonyl)imide ([C4mpip][Tf2N]) was investigated by classic molecular dynamics (MD) simulation. Differential scanning calorimetry (DSC) measurements verified that the binary mixture exhibited lower glass transition temperature than either of the pure room-temperature ionic liquids (RTILs). Moreover, the binary mixture gave rise to higher conductivity than the neat RTILs at lower temperature range. In order to study its capacitive performance in supercapacitors, simulations were performed of the mixture, and the neat RTILs used as electrolytes near an onion-like carbon (OLC) electrode at varying temperatures. The differential capacitance exhibited independence of the electrical potential applied for three electrolytes, which is in agreement with previous work on OLC electrodes in a different RTILs. Positive temperature dependence of the differential capacitance was observed, and it was dominated by the electrical double layer (EDL) thickness, which is for the first time substantiated in MD simulation.

Recent New Methodologies for Acetylenic Polymers with Advanced Functionalities.

PubMed

Qiu, Zijie; Han, Ting; Lam, Jacky W Y; Tang, Ben Zhong

2017-08-01

Polymers synthesized from acetylenic monomers often possess electronically unsaturated fused rings and thus show versatile optoelectronic properties and advanced functionalities. To expand the family of acetylenic polymers, development of new catalyst systems and synthetic routes is critically important. We summarize herein recent research progress on development of new methodologies towards functional polymers using alkyne building blocks since 2014. The polymerizations are categorized by the number of monomer components, namely homopolymerizations, two-component polymerizations, and multicomponent polymerizations. The properties and applications of acetylenic polymers, such as aggregation-induced emission, fluorescent photopatterning, light refraction, chemosensing, mechanochromism, chain helicity, etc., are also discussed.

Combined Experimental and Computational Study on the Unimolecular Decomposition of JP-8 Jet Fuel Surrogates. I. n-Decane (n-C10H22).

PubMed

Zhao, Long; Yang, Tao; Kaiser, Ralf I; Troy, Tyler P; Ahmed, Musahid; Belisario-Lara, Daniel; Ribeiro, Joao Marcelo; Mebel, Alexander M

2017-02-16

Exploiting a high temperature chemical reactor, we explored the pyrolysis of helium-seeded n-decane as a surrogate of the n-alkane fraction of Jet Propellant-8 (JP-8) over a temperature range of 1100-1600 K at a pressure of 600 Torr. The nascent products were identified in situ in a supersonic molecular beam via single photon vacuum ultraviolet (VUV) photoionization coupled with a mass spectroscopic analysis of the ions in a reflectron time-of-flight mass spectrometer (ReTOF). Our studies probe, for the first time, the initial reaction products formed in the decomposition of n-decane-including radicals and thermally labile closed-shell species effectively excluding mass growth processes. The present study identified 18 products: molecular hydrogen (H 2 ), C2 to C7 1-alkenes [ethylene (C 2 H 4 ) to 1-heptene (C 7 H 14 )], C1-C3 radicals [methyl (CH 3 ), vinyl (C 2 H 3 ), ethyl (C 2 H 5 ), propargyl (C 3 H 3 ), allyl (C 3 H 5 )], small C1-C3 hydrocarbons [methane (CH 4 ), acetylene (C 2 H 2 ), allene (C 3 H 4 ), methylacetylene (C 3 H 4 )], along with higher-order reaction products [1,3-butadiene (C 4 H 6 ), 2-butene (C 4 H 8 )]. On the basis of electronic structure calculations, n-decane decomposes initially by C-C bond cleavage (excluding the terminal C-C bonds) producing a mixture of alkyl radicals from ethyl to octyl. These alkyl radicals are unstable under the experimental conditions and rapidly dissociate by C-C bond β-scission to split ethylene (C 2 H 4 ) plus a 1-alkyl radical with the number of carbon atoms reduced by two and 1,4-, 1,5-, 1,6-, or 1,7-H shifts followed by C-C β-scission producing alkenes from propene to 1-octene in combination with smaller 1-alkyl radicals. The higher alkenes become increasingly unstable with rising temperature. When the C-C β-scission continues all the way to the propyl radical (C 3 H 7 ), it dissociates producing methyl (CH 3 ) plus ethylene (C 2 H 4 ). Also, at higher temperatures, hydrogen atoms can abstract hydrogen from C 10 H 22 to yield n-decyl radicals, while methyl (CH 3 ) can also abstract hydrogen or recombine with hydrogen to form methane. These n-decyl radicals can decompose via C-C-bond β-scission to C3 to C9 alkenes.

Description of toluene inhibition of methyl bromide biodegradation in seawater and isolation of a marine toluene oxidizer that degrades methyl bromide.

PubMed

Goodwin, Kelly D; Tokarczyk, Ryszard; Stephens, F Carol; Saltzman, Eric S

2005-07-01

Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are important precursors for destruction of stratospheric ozone, and oceanic uptake is an important component of the biogeochemical cycle of these methyl halides. In an effort to identify and characterize the organisms mediating halocarbon biodegradation, we surveyed the effect of potential cometabolic substrates on CH3Br biodegradation using a 13CH3Br incubation technique. Toluene (160 to 200 nM) clearly inhibited CH3Br and CH3Cl degradation in seawater samples from the North Atlantic, North Pacific, and Southern Oceans. Furthermore, a marine bacterium able to co-oxidize CH3Br while growing on toluene was isolated from subtropical Western Atlantic seawater. The bacterium, Oxy6, was also able to oxidize o-xylene and the xylene monooxygenase (XMO) pathway intermediate 3-methylcatechol. Patterns of substrate oxidation, lack of acetylene inhibition, and the inability of the toluene 4-monooxygenase (T4MO)-containing bacterium Pseudomonas mendocina KR1 to degrade CH3Br ruled out participation of the T4MO pathway in Oxy6. Oxy6 also oxidized a variety of toluene (TOL) pathway intermediates such as benzyl alcohol, benzylaldehyde, benzoate, and catechol, but the inability of Pseudomonas putida mt-2 to degrade CH3Br suggested that the TOL pathway might not be responsible for CH3Br biodegradation. Molecular phylogenetic analysis identified Oxy6 to be a member of the family Sphingomonadaceae related to species within the Porphyrobacter genus. Although some Sphingomonadaceae can degrade a variety of xenobiotic compounds, this appears to be the first report of CH3Br degradation for this class of organism. The widespread inhibitory effect of toluene on natural seawater samples and the metabolic capabilities of Oxy6 indicate a possible link between aromatic hydrocarbon utilization and the biogeochemical cycle of methyl halides.

Supramolecule-to-supramolecule transformations of coordination-driven self-assembled polygons.

PubMed

Zhao, Liang; Northrop, Brian H; Stang, Peter J

2008-09-10

Two types of supramolecular transformations, wherein a self-assembled Pt(II)-pyridyl metal-organic polygon is controllably converted into an alternative polygon, have been achieved through the reaction between cobalt carbonyl and the acetylene moiety of a dipyridyl donor ligand. A [6 + 6] hexagon is transformed into two [3 + 3] hexagons, and a triangle-square mixture is converted into [2 + 2] rhomboids. 1H and 31P NMR spectra are used to track the transformation process and evaluate the yield of new self-assembled polygons. Such transformed species are identified by electrospray ionization (ESI) mass spectrometry. This new kind of supramolecule-to-supramolecule transformations provides a viable means for constructing, and then converting, new self-assembled polygons.

Determination of trace amounts of tin in geological materials by atomic absorption spectrometry

USGS Publications Warehouse

Welsch, E.P.; Chao, T.T.

1976-01-01

An atomic absorption method is described for the determination of traces of tin in rocks, soils, and stream sediments. A dried mixture of the sample and ammonium iodide is heated to volatilize tin tetraiodide -which is then dissolved in 5 % hydrochloric acid, extracted into TOPO-MIBK, and aspirated into a nitrous oxide-acetylene flame. The limit of determination is 2 p.p.m. tin and the relative standard deviation ranges from 2 to 14 %. Up to 20 % iron and 1000 p.p.m. Cu, Pb, Zn, Mn, Hg, Mo, V, or W in the sample do not interfere. As many as 50 samples can be easily analyzed per man-day. ?? 1976.

Interstellar molecules - Origin by catalytic reactions on grain surfaces. [compound distribution analysis

NASA Technical Reports Server (NTRS)

Anders, E.; Hayatsu, R.; Studier, M. H.

1974-01-01

To determine the compound distribution formed by surface catalysis, mixtures of CO, D2, and ND2 were heated with nickel-iron or montmorillonite clay catalysts for 49-214 hours at 250 to 300 C. Compounds identified include most of the known polyatomic interstellar molecules, as well as homologous series of acetylenes, dienes, alcohols, aldehydes, ketones, ethers, esters, nitriles, amines, etc., and cyclic compounds such as furans and pyrroles. These homologous series are uniquely characteristic of surface catalysis. A search for the heavier members of these series, predicted to occur at 1/10th to 1/1,000th the abundance of the lightest members, thus comprises a crucial test of this mechanism.

Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kjeldsen, Lisbeth Stigaard; Ghisari, Mandana; Bonefeld-Jørgensen, Eva Cecilie, E-mail: ebj@mil.au.dk

The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferasemore » reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [{sup 3}H]{sub 2}O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks. - Highlights: • Currently used pesticides possess endocrine-disrupting (ED) potential in vitro. • ED effects can be mediated via sex hormone receptors and/or the aromatase enzyme. • Additive mixture effects on androgen receptor transactivity were observed.« less

Acetylenic carbon allotrope

DOEpatents

Lagow, R.J.

1998-02-10

A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein. 17 figs.

Methyl fluoride-13C in nematic liquid crystals: Anisotropy of the indirect 13C-19F spin-spin coupling and of the 1H, 13C, and 19F chemical shieldings

NASA Astrophysics Data System (ADS)

Jokisaari, J.; Hiltunen, Y.; Lounila, J.

1986-09-01

The anisotropy of the indirect 13C-19F spin-spin coupling tensor of methyl fluoride-13C in the liquid crystals ZLI 1167, EBBA, their mixtures, phase IV, and phase 1221 was studied by applying 1H and 19F NMR spectroscopy. The relative anisotropy ΔJCF/JCF gets values between -4.3 (in ZLI 1167) and +30.7 (in EBBA) when determined in the conventional way from the experimental dipolar coupling constants taking into account only harmonic vibrational corrections. The inclusion of the deformational corrections in both the direct and indirect C-F coupling tensors leads to a constant, solvent independent relative anisotropy of -2.5±0.2. This result is also obtained when a mixture of the liquid crystals ZLI 1167 and EBBA is used which mixture gives an undistorted geometry for methyl fluoride. The chemical shielding anisotropies ΔσH, ΔσC, and ΔσF for methyl fluoride were determined by applying the method of mixing two thermotropic nematogens (ZLI 1167 and EBBA) with opposite anisotropies of diamagnetic susceptibility. The results ΔσH =+5.2±0.2 ppm, ΔσC =+87±4 ppm, and ΔσF =-90±4 ppm are in fair agreement with theoretical calculations.

[Effects of organic and inorganic fertilizers on emission and sources of N2O in vegetable soils.

PubMed

Lin, Wei; Ding, Jun Jun; Li, Yu Zhong; Xu, Chun Ying; Li, Qiao Zhen; Zheng, Qian; Zhuang, Shan

2018-05-01

To clarify the microbial pathway of the N 2 O production and consumption under different fertilizers and provide theoretical basis for the reduction of N 2 O emission and rational management of fertilization in vegetable soils, we examined dynamics of N 2 O flux and isotope signatures under different fertilizer treatments in the vegetable soils of Beijing, by setting up four treatments (organic-acetylene, organic-nonacetylene, inorganic-acetylene, inorganic-nonacetylene) and using the stable isotope technique of natural N 2 O abundance. The results showed that the cumulative N 2 O emission from organic-acetylene group, organic-nonacetylene group, inorganic-acetylene group and inorganic-nonacetylene group was (374±37), (283±34), (458±36), (355±41) g·m -2 in cabbage growing season, respectively. N 2 O fluxes were significantly lower in treatments with organic fertilizer than those with inorganic fertilizer and significantly higher in acetylene group than nonacetylene group. The degree of N 2 O reduction were similar in both fertilizer treatments, and higher nitrification was found in inorganic fertilizer than organic fertilizer treatments. Acetylene only inhibited partial nitrification and partial N 2 O reduction at the peak of N 2 O emission. When the emission was reduced, N 2 O reduction could be completely suppressed. Therefore, the inorganic fertilizer might trigger nitrification and promote higher N 2 O emission. The high concentration of N 2 O could withstand that acetylene to inhibite N 2 O reduction. Hence, using organic fertilizers instead of some inorganic ones could effectively reduce N 2 O emission in vegetable soils of Beijing. The N 2 O concentration threshold should be considered when we identify N 2 O source by acetylene inhibition method.

Tropospheric and lower stratospheric vertical profiles of ethane and acetylene

NASA Technical Reports Server (NTRS)

Cronn, D.; Robinson, E.

1979-01-01

The first known vertical distributions of ethane and acetylene which extend into the lower stratosphere are reported. The average upper tropospheric concentrations, between 20,000 ft and 35,000 ft, near 37 deg N-123 deg W were 1.2 micrograms/cu m (1.0 ppb) for ethane and 0.24 micrograms /cu m (0.23 ppb) for acetylene while the values near 9 N-80 W were 0.95 micrograms/cu m (0.77 ppb) and 0.09 micrograms/cu m (0.09 ppb), respectively. Detectable quantities of both ethane and acetylene are present in the lower stratosphere. There is a sharp decrease in the levels of these two compounds as one crosses the tropopause and ascends into the lower stratosphere. The observed levels of ethane and acetylene may allow some impact on the background chemistry of the troposphere and stratosphere.

Structure of the non-redox-active tungsten/[4Fe:4S] enzyme acetylene hydratase.

PubMed

Seiffert, Grazyna B; Ullmann, G Matthias; Messerschmidt, Albrecht; Schink, Bernhard; Kroneck, Peter M H; Einsle, Oliver

2007-02-27

The tungsten-iron-sulfur enzyme acetylene hydratase stands out from its class because it catalyzes a nonredox reaction, the hydration of acetylene to acetaldehyde. Sequence comparisons group the protein into the dimethyl sulfoxide reductase family, and it contains a bis-molybdopterin guanine dinucleotide-ligated tungsten atom and a cubane-type [4Fe:4S] cluster. The crystal structure of acetylene hydratase at 1.26 A now shows that the tungsten center binds a water molecule that is activated by an adjacent aspartate residue, enabling it to attack acetylene bound in a distinct, hydrophobic pocket. This mechanism requires a strong shift of pK(a) of the aspartate, caused by a nearby low-potential [4Fe:4S] cluster. To access this previously unrecognized W-Asp active site, the protein evolved a new substrate channel distant from where it is found in other molybdenum and tungsten enzymes.

The determination of vanadium in brines by atomic absorption spectroscopy

USGS Publications Warehouse

Crump-Wiesner, Hans J.; Feltz, H.R.; Purdy, W.C.

1971-01-01

A standard addition method is described for the determination of vanadium in brines by atomic absorption spectroscopy with a nitrous oxide-acetylene flame. Sample pH is adjusted to 1.0 with concentrated hydrochloric acid and the vanadium is directly extracted with 5% cupferron in methyl isobutyl ketone (MIBK). The ketone layer is then aspirated into the flame and the recorded absorption values are plotted as a function of the concentration of the added metal. As little as 2.5 ??g l-1 of vanadium can be detected under the conditions of the procedure. Tungsten and tin interfere when present in excess of 5 and 10 ??g ml-1, respectively. The concentrations of the two interfering ions normally found in brines are well below interference levels. ?? 1971.

Design, synthesis and antitubercular evaluation of novel 2-substituted-3H-benzofuro benzofurans via palladium-copper catalysed Sonagashira coupling reaction.

PubMed

Yempala, Thirumal; Sridevi, Jonnalagadda Padma; Yogeeswari, Perumal; Sriram, Darmarajan; Kantevari, Srinivas

2013-10-01

A series of novel natural product like 2-substiuted-3H-benzofurobenzofurans designed by molecular hybridization were synthesized in very good yields. The key reactions involved in the synthesis are iodination of 2-dibenzofuranol using iodine monochloride followed by palladium-copper catalyzed Sonagashira-coupling of 1-iododibenzofuran-2-ol with various alkyl and aryl acetylenes. Among the all 10 new compounds screened for in vitro anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv, 2-(4-methoxy-2-methyl phenyl)-3H-benzofuro[3,2-e]benzofuran (7c) was found to be most active with MIC 3.12 μg/mL and has shown lower cytotoxicity with good therapeutic index. Copyright © 2013 Elsevier Ltd. All rights reserved.

Computational Screening of MOFs for Acetylene Separation

PubMed Central

Nemati Vesali Azar, Ayda; Keskin, Seda

2018-01-01

Efficient separation of acetylene (C2H2) from CO2 and CH4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs) are great candidates for adsorption-based C2H2/CO2 and C2H2/CH4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C2H2/CO2 and C2H2/CH4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C2H2/CO2 and C2H2/CH4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C2H2/CO2 selectivities of 49, 47, 24 and C2H2/CH4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C2H2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4 and 11 Å, surface areas in the range of 600–1,200 m2/g and porosities between 0.4 and 0.6 for selective separation of C2H2 from CO2 and CH4. These results will guide the future studies for the design of new MOFs with high C2H2 separation potentials. PMID:29536004

Ester-Based Electrolytes for Low-Temperature Li-Ion Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall; Bugga, Ratnakumar

2005-01-01

Electrolytes comprising LiPF6 dissolved at a concentration of 1.0 M in five different solvent mixtures of alkyl carbonates have been found to afford improved performance in rechargeable lithium-ion electrochemical cells at temperatures as low as -70 C. These and other electrolytes have been investigated in continuing research directed toward extending the lower limit of practical operating temperatures of Li-ion cells. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles, the most recent being Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells (NPO-30226), NASA Tech Briefs, Vol. 27, No. 1 (January 2003), page 46. The ingredients of the present solvent mixtures are ethylene carbonate (EC), ethyl methyl carbonate (EMC), methyl butyrate (MB), methyl propionate (MP), ethyl propionate (EP), ethyl butyrate (EB), and ethyl valerate (EV). In terms of volume proportions of these ingredients, the present solvent mixtures are 1EC + 1EMC + 8MB, 1EC + 1EMC + 8EB, 1EC + 1EMC + 8MP, 1EC + 1EMC + 8EV, and 1EC + 9EMC. These electrolytes were placed in Liion cells containing carbon anodes and LiNi0.8Co0.2O2 cathodes, and the low-temperature electrical performances of the cells were measured. The cells containing the MB and MP mixtures performed best.

A study on flammability limits of fuel mixtures.

PubMed

Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki; Sekiya, Akira

2008-07-15

Flammability limit measurements were made for various binary and ternary mixtures prepared from nine different compounds. The compounds treated are methane, propane, ethylene, propylene, methyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. The observed values of lower flammability limits of mixtures were found to be in good agreement to the calculated values by Le Chatelier's formula. As for the upper limits, however, some are close to the calculated values but some are not. It has been found that the deviations of the observed values of upper flammability limits from the calculated ones are mostly to lower concentrations. Modification of Le Chatelier's formula was made to better fit to the observed values of upper flammability limits. This procedure reduced the average difference between the observed and calculated values of upper flammability limits to one-third of the initial value.

Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures

USGS Publications Warehouse

Culbertson, Charles W.; Zehnder, Alexander J. B.; Oremland, Ronald S.

1981-01-01

Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C2H2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C2H2.

Detection of acetylene in the Saturnian atmosphere, using the IUE satellite

NASA Technical Reports Server (NTRS)

Moos, H. W.; Clarke, J. T.

1979-01-01

Direct evidence for the presence of acetylene in the upper part of the Saturnian atmosphere is reported. This evidence consists of two spectra of Saturn obtained by using the low-dispersion mode of the short-wavelength spectrograph on the IUE satellite. A series of distinct absorption bands in the reflected solar radiation at 1750 A is attributed to acetylene. The reciprocal of the acetylene cross section at 1750 A is shown to imply 7 x 10 to the 17th molecules/sq cm in the reflecting layer. It is concluded that the radiation at 1750 A originates from less than 2.3 km-amagat within the atmosphere.

Nanocomposite vacuum-Arc TiC/a-C:H coatings prepared using an additional ionization of acetylene

NASA Astrophysics Data System (ADS)

Trakhtenberg, I. Sh.; Gavrilov, N. V.; Emlin, D. R.; Plotnikov, S. A.; Vladimirov, A. B.; Volkova, E. G.; Rubshtein, A. P.

2014-07-01

The composition, structure, and properties of TiC/a-C:H coatings obtained by simultaneous vacuum-arc deposition of titanium and carbon in a low-pressure argon-acetylene medium additionally activated by a low-energy (a few hundreds of electron-volts) electron beam. The creation of conditions under which the decomposition of acetylene is provided by the ionization and dissociation of molecules due to electron impacts and by the recharging of molecules through titanium and argon ions with subsequent dissociation should favor the most complete decomposition of acetylene in a wide range of pressures. With increasing acetylene pressure, the structure of the nanocomposite coating changes: the size of TiC crystallites decreases, and the fraction of interfaces (or the fraction of regions with a disordered (amorphous) structure) increases. The application of a bias voltage leads to an increase in the sizes of TiC nanocrystallites. The coatings with a maximum microhardness (˜40 GPa) have been obtained without the action of an electron beam under an acetylene pressure of ˜0.05-0.08 Pa and the atomic ratio Ti: C ˜ 0.9: 1.1 in the coating.

Method of absorbing UF.sub.6 from gaseous mixtures in alkamine absorbents

DOEpatents

Lafferty, Robert H.; Smiley, Seymour H.; Radimer, Kenneth J.

1976-04-06

A method of recovering uranium hexafluoride from gaseous mixtures employing as an absorbent a liquid composition at least one of the components of which is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2.

GRAPHITE PRODUCTION UTILIZING URANYL NITRATE HEXAHYDRATE CATALYST

DOEpatents

Sheinberg, H.; Armstrong, J.R.; Schell, D.H.

1964-03-10

ABS>The graphitizing of a mixture composed of furfuryl alcohol binder and uranyl nitrate hexahydrate hardener and the subsequent curing, baking, and graphitizing with pressure being initially applied prior to curing are described. The pressure step may be carried out by extrusion, methyl cellulose being added to the mixture before the completion of extrusion. Uranium oxide may be added to the graphitizable mixture prior to the heating and pressure steps. The graphitizable mixture may consist of discrete layers of different compositions. (AEC)

Viscosity of nonelectrolyte liquid mixtures. IV. Binary mixtures containing p-Dioxane

NASA Astrophysics Data System (ADS)

Oswal, S. L.; Oswal, P.; Phalak, R. P.

1996-11-01

Measurements of the viscosity η and density p are reported for eight binary mixtures of p-dioxane with methylcyclohexane, l-chlorohexane, l-bromohexane, p-xylene, propylbenzene, methyl acetate, butyl acetate. anyl acetate at 303.15 K. The viscosity data haw been correlated with the equations of Grunbeng Nissan. of McAllister, and of Auslaendcr. The relation among the excess viscosity Δ In η, excess Gibbs energy of activation ΔG* E of viscous flow. and intermolecular interaction in these mixtures is discussed.

Measuring ethane and acetylene in Antarctic ice cores to quantify long-term hydrocarbon emissions from tropical fires

NASA Astrophysics Data System (ADS)

Nicewonger, M. R.; Aydin, M.; Prather, M. J.; Saltzman, E. S.

2017-12-01

This study examines ethane (C2H6) and acetylene (C2H2) in polar ice cores in order to reconstruct variations in the atmospheric levels of these trace gases over the past 2,000 years. Both of these non-methane hydrocarbons are released from fossil fuel, biofuel, and biomass burning. Ethane, but not acetylene, is also emitted from natural geologic outgassing of hydrocarbons. In an earlier study, we reported ethane levels in Greenland and Antarctic ice cores showing roughly equal contributions from biomass burning and geologic emissions to preindustrial atmospheric ethane levels (Nicewonger et al., 2016). Here we introduce acetylene as an additional constraint to better quantify preindustrial variations in the emissions from these natural hydrocarbon sources. Here we present 30 new measurements of ethane and acetylene from the WDC-06A ice core from WAIS Divide and the newly drilled South Pole ice core (SPICECORE). Ethane results display a gradual decline from peak levels of 110 ppt at 1400 CE to a minimum of 60-80 ppt during 1700-1875 CE. Acetylene correlates with ethane (r2 > 0.4), dropping from peak levels of 35 ppt at 1400 CE to 15-20 ppt at 1875 CE. The covariance between the two trace gases implies that the observed changes are likely caused by decreasing emissions from low latitude biomass burning. We will discuss results from chemical transport modeling and sensitivity tests and the implications for the preindustrial ethane and acetylene budgets.

Preparation of olanzapine and methyl-β-cyclodextrin complexes using a single-step, organic solvent-free supercritical fluid process: An approach to enhance the solubility and dissolution properties.

PubMed

Rudrangi, Shashi Ravi Suman; Trivedi, Vivek; Mitchell, John C; Wicks, Stephen Richard; Alexander, Bruce David

2015-10-15

The purpose of this study was to evaluate a single-step, organic solvent-free supercritical fluid process for the preparation of olanzapine-methyl-β-cyclodextrin complexes with an express goal to enhance the dissolution properties of olanzapine. The complexes were prepared by supercritical carbon dioxide processing, co-evaporation, freeze drying and physical mixing. The prepared complexes were then analysed by differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, solubility and dissolution studies. Computational molecular docking studies were performed to study the formation of molecular inclusion complexation of olanzapine with methyl-β-cyclodextrin. All the binary mixtures of olanzapine with methyl-β-cyclodextrin, except physical mixture, exhibited a faster and greater extent of drug dissolution than the drug alone. Products obtained by the supercritical carbon dioxide processing method exhibited the highest apparent drug dissolution. The characterisation by different analytical techniques suggests complete complexation or amorphisation of olanzapine and methyl-β-cyclodextrin complexes prepared by supercritical carbon dioxide processing method. Therefore, organic solvent-free supercritical carbon dioxide processing method proved to be novel and efficient for the preparation of solid inclusion complexes of olanzapine with methyl-β-cyclodextrin. The preliminary data also suggests that the complexes of olanzapine with methyl-β-cyclodextrin will lead to better therapeutic efficacy due to better solubility and dissolution properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s

PubMed Central

Baesman, Shaun M.; Oremland, Ronald S.

2015-01-01

Abstract We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. Key Words: Acetylene—Fermentation—Isotope fractionation—Enceladus—Life detection. Astrobiology 15, 977–986. PMID:26539733

Phase equilibrium measurements on nine binary mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilding, W.V.; Giles, N.F.; Wilson, L.C.

1996-11-01

Phase equilibrium measurements have been performed on nine binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following systems at two temperatures each: (aminoethyl)piperazine + diethylenetriamine; 2-butoxyethyl acetate + 2-butoxyethanol; 2-methyl-2-propanol + 2-methylbutane; 2-methyl-2-propanol + 2-methyl-2-butene; methacrylonitrile + methanol; 1-chloro-1,1-difluoroethane + hydrogen chloride; 2-(hexyloxy)ethanol + ethylene glycol; butane + ammonia; propionaldehyde + butane. Equilibrium vapor and liquid phase compositions were derived form the PTx data using the Soave equation of state to represent the vapor phase and the Wilson or the NRTL activity coefficient model to represent the liquid phase. A large immiscibility region existsmore » in the butane + ammonia system at 0 C. Therefore, separate vapor-liquid-liquid equilibrium measurements were performed on this system to more precisely determine the miscibility limits and the composition of the vapor phase in equilibrium with the two liquid phases.« less

Secondary metabolites of the grapevine pathogen Eutypa lata inhibit mitochondrial respiration, based on a model bioassay using the yeast Saccharomyces cerevisiae.

PubMed

Kim, Jong H; Mahoney, Noreen; Chan, Kathleen L; Molyneux, Russell J; Campbell, Bruce C

2004-10-01

Acetylenic phenols and a chromene isolated from the grapevine fungal pathogen Eutypa lata were examined for mode of toxicity. The compounds included eutypine (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl aldehyde), eutypinol (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl alcohol), eulatachromene, 2- isoprenyl-5-formyl-benzofuran, siccayne, and eulatinol. A bioassay using the yeast Saccharomyces cerevisiae showed that all compounds were either lethal or inhibited growth. A respiratory assay using 2,3,5-triphenyltetrazolium (TTC) indicated that eutypinol and eulatachromene inhibited mitochondrial respiration in wild-type yeast. Bioassays also showed that 2- isoprenyl-5-formyl-benzofuran and siccayne inhibited mitochondrial respiration in the S. cerevisiae deletion mutant vph2Delta, lacking a vacuolar type H (+) ATPase (V-ATPase) assembly protein. Cell growth of tsa1Delta, a deletion mutant of S. cerevisiae lacking a thioredoxin peroxidase (cTPx I), was greatly reduced when grown on media containing eutypinol or eulatachromene and exposed to hydrogen peroxide (H(2)O(2)) as an oxidative stress. This reduction in growth establishes the toxic mode of action of these compounds through inhibition of mitochondrial respiration.

Investigation of Unexpected Reaction Intermediates in the Alkaline Hydrolysis of Methyl 3,5-Dinitrobenzoate

ERIC Educational Resources Information Center

Silva, Clesia C.; Silva, Ricardo O.; Navarro, Daniela M. A. F.; Navarro, Marcelo

2009-01-01

An experimental project aimed at identifying stable reaction intermediates is described. Initially, the studied reaction appears to involve the simple hydrolysis, by aqueous sodium hydroxide, of methyl 3,5-dinitrobenzoate dissolved in dimethyl sulfoxide. On mixing the substrates, however, the reaction mixture unexpectedly turns an intense red in…

Analysis of residual monomers in dendritic methacrylate copolymers and composites by HPLC and headspace-GC/MS.

PubMed

Viljanen, Eeva K; Langer, Sarka; Skrifvars, Mikael; Vallittu, Pekka K

2006-09-01

The aim of this study was to analyze the residual monomer content of photopolymerized dendritic methacrylate copolymers and particulate filler composites. Headspace-gas chromatography/mass spectrometry (HS-GC/MS) was compared with high performance liquid chromatography (HPLC). The resin mixtures consisted of a dendritic methacrylate monomer, methyl methacrylate and acetoacetoxyethyl methacrylate in varied proportions. In addition, one of the composites contained 1,4-butanediol dimethacrylate. Camphorquinone and 2-(N,N-dimethylamino)ethyl methacrylate were used as the light-activated initiator system. The content of residual methyl methacrylate and acetoacetoxyethyl methacrylate after 40 s photopolymerization were analyzed with HPLC and HS-GC/MS. The content of residual methyl methacrylate decreased and residual acetoacetoxyethyl methacrylate increased with increasing concentration of acetoacetoxyethyl methacrylate in the resin mixture. The results with both methods had the same trend. The addition of acetoacetoxyethyl methacrylate enhanced the copolymerization of methyl methacrylate, but did not decrease the total residual monomer content. The HS-GC/MS method was found to be a feasible method in the analysis of low-boiling residuals in dental polymers.

Phase equilibrium measurements on twelve binary mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giles, N.F.; Wilson, H.L.; Wilding, W.V.

1996-11-01

Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin; methanol + hydrogen cyanide. For these systems, equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson, NRTL, or Redlich-Kister activity coefficient model tomore » represent the liquid phase. The infinite dilution activity coefficient of methylamine in N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone-rich half of the binary. Liquid-liquid equilibrium studies were made on the triethylene glycol + 1-pentene system at two temperatures by directly analyzing samples taken from each liquid phase.« less

Impact of Chemical Proportions on the Acute Neurotoxicity of a Mixture of Seven Carbamates in Rats

EPA Science Inventory

Environmental exposures generally involve multiple chemicals and pathways, and statistical methodologies now exist to evaluate interactions among any number of chemicals in defined mixtures. N-methyl carbamate pesticides are presumed to act through a common mode of action, that i...

Fire Extinguishing Agents for Rocket Fuels

DTIC Science & Technology

1951-09-01

Fl&saable Are© for Mixtures of ’Hydrogen? Carbon Dioxid© and Air - - - - —*_-*.«. r. ----- . Flesnablo Area for Mixtures of...MÜxturesof Ammonia,~ Carbon "- Dioxide"" aad" 25 15 16 Flammable Afea for: Mixtures of Ammonia, Methyl. Bromide aad Air...at 6«,7°C. This compound was Obtained from Carbide and Carbon Chemicals Corporation end was purified by rectification. ^ . ’ ’Ethanol (G2HBOH

49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

Code of Federal Regulations, 2014 CFR

2014-10-01

... fiberboard boxes with inside metal cans containing not over one pound each, or inside metal cans with a... packaged as follows in metal boxes (4A, 4B or 4N) or wooden boxes (4C1, 4C2, 4D or 4F) with inner glass... mm (0.5 inch) of absorbent material. Total amount of liquid in the outer box must not exceed 11 kg...

49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

Code of Federal Regulations, 2013 CFR

2013-10-01

... fiberboard boxes with inside metal cans containing not over one pound each, or inside metal cans with a... packaged as follows in metal boxes (4A, 4B or 4N) or wooden boxes (4C1, 4C2, 4D or 4F) with inner glass... mm (0.5 inch) of absorbent material. Total amount of liquid in the outer box must not exceed 11 kg...

Optimization of gas chromatographic method for the enantioseparation of arylpropionic non-steroidal anti-inflammatory drug methyl esters.

PubMed

Petrović, Marinko; Debeljak, Zeljko; Blazević, Nikola

2005-09-15

The gas chromatography (GC) method for enantioseparation of well-known non-steroidal anti-inflammatory drugs ibuprofen, fenoprofen and ketoprofen methyl esters mixture was developed. Best enantioseparation was performed on capillary column with heptakis-(2,3-di-O-methyl-6-O-t-butyldimethyl-silyl)-beta-cyclodextrin stationary phase and hydrogen used as a carrier gas. Initial temperature, program rate and carrier pressure were optimized to obtain best resolution between enantiomers.

Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiter's Great Red Spot

NASA Astrophysics Data System (ADS)

Carlson, R. W.; Baines, K. H.; Anderson, M. S.; Filacchione, G.; Simon, A. A.

2016-08-01

The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.

Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiters Great Red Spot

NASA Technical Reports Server (NTRS)

Carlson, Robert W.; Baines, Kevin H.; Anderson, M. S.; Filacchione, G.; Simon, A. A.

2016-01-01

The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3 ) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2 ). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.

Acetylene terminated matrix resins

NASA Technical Reports Server (NTRS)

Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

1985-01-01

The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee A.; Barton, Katherine

2012-01-01

State-of-the-art carbon dioxide reduction technology uses a Sabatier reactor to recover water from metabolic carbon dioxide. In order to maximize oxygen loop closure, a byproduct of the system, methane, must be reduced to recover hydrogen. NASA is currently exploring a microwave plasma methane pyrolysis system for this purpose. The resulting product stream of this technology includes unreacted methane, product hydrogen, and acetylene. The hydrogen and the small amount of unreacted methane resulting from the pyrolysis process can be returned to the Sabatier reactor thereby substantially improving the overall efficiency of the system. However, the acetylene is a waste product that must be removed from the pyrolysis product. Two materials have been identified as potential sorbents for acetylene removal: zeolite 4A, a commonly available commercial sorbent, and HKUST-1, a newly developed microporous metal. This paper provides an explanation of the rationale behind acetylene removal and the results of separation testing with both materials

Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee A.; Barton, Katherine

2011-01-01

State-of-the-art carbon dioxide reduction technology uses a Sabatier reactor to recover water from metabolic carbon dioxide. In order to maximize oxygen loop closure, a byproduct of the system, methane, must be reduced to recover hydrogen. NASA is currently exploring a microwave plasma methane pyrolysis system for this purpose. The resulting product stream of this technology includes unreacted methane, product hydrogen, and acetylene. The hydrogen and the small amount of unreacted methane resulting from the pyrolysis process can be returned to the Sabatier reactor thereby substantially improving the overall efficiency of the system. However, the acetylene is a waste product that must be removed from the pyrolysis product. Two materials have been identified as potential sorbents for acetylene removal: zeolite 4A, a commonly available commercial sorbent, and HKUST-1, a newly developed microporous metal. This paper provides an explanation of the rationale behind acetylene removal and the results of separation testing with both materials.

Acetylene measurement in flames by chirp-based quantum cascade laser spectrometry.

PubMed

Quine, Zachary R; McNesby, Kevin L

2009-06-01

We have designed and characterized a mid-IR spectrometer built around a pulsed distributed-feedback quantum cascade laser using the characteristic frequency down-chirp to scan through the spectral region 6.5 cm(-1) spectral region. The behavior of this chirp is extensively measured. The accuracy and detection limits of the system as an absorption spectrometer are demonstrated first by measuring spectra of acetylene through a single pass 16 cm absorption cell in real time at low concentrations and atmospheric pressure. The smallest detectable peak is measured to be approximately 1.5 x 10(-4) absorbance units, yielding a minimum detectable concentration length product of 2.4 parts per million meter at standard temperature and pressure. This system is then used to detect acetylene within an ethylene-air opposed flow flame. Measurements of acetylene content as a function of height above the fuel source are presented, as well as measurements of acetylene produced in fuel breakdown as a function of preinjection fuel temperature.

Thermal Decomposition of Potential Ester Biofuels. Part I: Methyl Acetate and Methyl Butanoate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porterfield, Jessica P.; Bross, David H.; Ruscic, Branko

2017-06-09

Two methyl esters have been examined as models for the pyrolysis of biofuels. Dilute samples (0.06 - 0.13%) of methyl acetate (CH 3COOCH 3) and methyl butanoate (CH 3CH 2CH 2COOCH 3) were entrained in (He, Ar) carrier gas and decomposed in a set of flash-pyrolysis micro-reactors. The pyrolysis products resulting from the methyl esters were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by matrix infrared absorption spectroscopy. Pyrolysis pressures in the pulsed micro-reactor were roughly 20 Torr and residence times through the reactors were approximately 25 - 150 µs. Reactor temperatures ofmore » 300 – 1600 K were explored. Decomposition of CH 3COOCH 3 commences at 1000 K and the initial products are (CH 2=C=O and CH 3OH). As the micro-reactor is heated to 1300 K, a mixture of (CH 2=C=O and CH 3OH, CH 3, CH 2=O, H, CO, CO 2) appears. The thermal cracking of CH 3CH 2CH 2COOCH 3 begins at 800 K with the formation of (CH 3CH 2CH=C=O, CH 3OH). By 1300 K, the pyrolysis of methyl butanoate yields a complex mixture of (CH 3CH 2CH=C=O, CH 3OH, CH 3, CH 2=O, CO, CO 2, CH 3CH=CH 2, CH 2CHCH 2, CH 2=C=CH 2, HCCCH 2, CH 2=C=C=O, CH 2=CH 2, HCΞCH, CH 2=C=O). Based on the results from the thermal cracking of methyl acetate and methyl butanoate, we predict several important decomposition channels for the pyrolysis of fatty acid methyl esters, R CH 2-COOCH 3. The lowest energy fragmentation will be a 4-center elimination of methanol to form the ketene, RCH=C=O. At higher temperatures, concerted fragmentation to radicals will ensue to produce a mixture of species: (RCH 2 + CO 2 + CH 3) and (RCH 2 + CO + CH 2=O + H). Thermal cracking of the β C-C bond of the methyl ester will generate the radicals (R and H) as well as CH 2=C=O + CH 2=O. The thermochemistry of methyl acetate and its fragmentation products have been obtained via the Active Thermochemical Tables (ATcT) approach, resulting in Δ fH 298(CH 3COOCH 3) = -98.7 ± 0.2 kcal mol -1, Δ fH 298(CH 3CO 2) = -45.7 ± 0.3 kcal mol -1, and Δ fH 298(COOCH 3) = -38.3 ± 0.4 kcal mol -1.« less

Novel Concept of Frequency-Combs Interferometric Spectroscopy in the Mid-IR for Significantly Enhanced Detection of Explosives

DTIC Science & Technology

2015-12-01

frequency combs. Ultrasensitive detection of methane, isotopic carbon dioxide, carbon monoxide, formaldehyde, acetylene, and ethylene was performed in...rmaldehyde, acetylene, and ethylene was perfo rmed in the spectral range 2.5- 5 11111 using intracav ity spectroscopy in broadband optical parametric osc...trace point detection of methane, carbon dioxide, isotopic (13C02) carbon dioxide, carbon monoxide, ethylene , acetylene, and formaldehyde and

Vapor pressures of acetylene at low temperatures

NASA Technical Reports Server (NTRS)

Masterson, C. M.; Allen, John E., Jr.; Kraus, G. F.; Khanna, R. K.

1990-01-01

The atmospheres of many of the outer planets and their satellites contain a large number of hydrocarbon species. In particular, acetylene (C2H2) has been identified at Jupiter, Saturn and its satellite Titan, Uranus and Neptune. In the lower atmospheres of these planets, where colder temperatures prevail, the condensation and/or freezing of acetylene is probable. In order to obtain accurate models of the acetylene in these atmospheres, it is necessary to have a complete understanding of its vapor pressures at low temperatures. Vapor pressures at low temperatures for acetylene are being determined. The vapor pressures are measured with two different techniques in order to cover a wide range of temperatures and pressures. In the first, the acetylene is placed in a sample tube which is immersed in a low temperature solvent/liquid nitrogen slush bath whose temperature is measured with a thermocouple. The vapor pressure is then measured directly with a capacitance manometer. For lower pressures, a second technique which was called the thin-film infrared method (TFIR) was developed. It involves measuring the disappearance rate of a thin film of acetylene at a particular temperature. The spectra are then analyzed using previously determined extinction coefficient values, to determine the disappearance rate R (where R = delta n/delta t, the number of molecules that disappear per unit time). This can be related to the vapor pressure directly. This technique facilitates measurement of the lower temperatures and pressures. Both techniques have been calibrated using CO2, and have shown good agreement with the existing literature data.

Can Analysis of Acetylene and Its Biodegradation Products in Enceladus Plumes be Used to Detect the Presence of Sub-Surface Life?

NASA Astrophysics Data System (ADS)

Miller, L. G.; Baesman, S. M.; Oremland, R. S.

2014-12-01

The search for biosignatures of life on Earth includes measurement of the stable isotope fractionation of reactants and products attributed to enzymatic processes and comparison with the often smaller chemical (abiotic) fractionation. We propose that this approach might be applied to study the origin and fate of organic compounds contained in water vapor plumes emanating from Enceladus or other icy bodies, perhaps revealing information about the potential for biology occurring within a sub-surface "habitable" zone. Methanol and C2-hydrocarbons including ethylene, ethane and acetylene (C2H2) have been identified in the plumes of Enceladus. Biological degradation of acetylene proceeds by anaerobic fermentation via acetylene hydratase through acetaldehyde, with a second enzyme (acetaldehyde dismutase) forming acetate and ethanol. We found that incubation of cultures of acetylene-fermenting bacteria exhibit a kinetic isotope effect (KIE) associated with the net removal of C2H2. Consumption of acetylene by both growing and washed-cell cultures of bacteria closely related to Pelobacter acetylenicus (e.g, strain SFB93) was accompanied by a carbon isotopic fractionation of about 2 per mil (KIE = 1.8-2.7 ‰), a result we are examining with other cultures of acetylene fermenters. In addition, we are measuring the carbon isotopic composition of acetaldehyde, ethanol and acetate during fermentation to learn whether these products are fractionated sufficiently, relative to their substrate, to warrant measurement of their isotopic composition in Enceladus (or Europa) plumes to indicate enzymatic activity in liquid environments below the crust of these moons.

Characterization of the Minimum Energy Paths for the Ring Closure Reactions of C4H3 with Acetylene

NASA Technical Reports Server (NTRS)

Walch, Stephen P.

1995-01-01

The ring closure reaction of C4H3 with acetylene to give phenyl radical is one proposed mechanism for the formation of the first aromatic ring in hydrocarbon combustion. There are two low-lying isomers of C4H3; 1-dehydro-buta-l-ene-3-yne (n-C4H3) and 2-dehydro-buta-l-ene-3-yne (iso-C4H3). It has been proposed that only n-C4H3 reacts with acetylene to give phenyl radical, and since iso-C4H3 is more stable than n-C4H3, formation of phenyl radical by this mechanism is unlikely. We report restricted Hartree-Fock (RHF) plus singles and doubles configuration interaction calculations with a Davidson's correction (RHF+1+2+Q) using the Dunning correlation consistent polarized valence double zeta basis set (cc-pVDZ) for stationary point structures along the reaction pathway for the reactions of n-C4H3 and iso-C4H3 with acetylene. n-C4H3 plus acetylene (9.4) has a small entrance channel barrier (17.7) (all energetics in parentheses are in kcal/mol with respect to iso-C4H3 plus acetylene) and the subsequent closure steps leading to phenyl radical (-91.9) are downhill with respect to the entrance channel barrier. Iso-C4H3 Plus acetylene also has an entrance channel barrier (14.9) and there is a downhill pathway to 1-dehydro-fulvene (-55.0). 1-dehydro-fulvene can rearrange to 6-dehydro-fulvene (-60.3) by a 1,3-hydrogen shift over a barrier (4.0), which is still below the entrance channel barrier, from which rearrangement to phenyl radical can occur by a downhill pathway. Thus, both n-C4H3 and iso-C4H3 can react with acetylene to give phenyl radical with small barriers.

Intramolecular competition between n-pair and π-pair hydrogen bonding: Microwave spectrum and internal dynamics of the pyridine–acetylene hydrogen-bonded complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackenzie, Rebecca B.; Dewberry, Christopher T.; Leopold, Kenneth R., E-mail: A.C.Legon@bristol.ac.uk, E-mail: david.tew@bristol.ac.uk, E-mail: kleopold@umn.edu

2015-09-14

a-type rotational spectra of the hydrogen-bonded complex formed from pyridine and acetylene are reported. Rotational and {sup 14}N hyperfine constants indicate that the complex is planar with an acetylenic hydrogen directed toward the nitrogen. However, unlike the complexes of pyridine with HCl and HBr, the acetylene moiety in HCCH—NC{sub 5}H{sub 5} does not lie along the symmetry axis of the nitrogen lone pair, but rather, forms an average angle of 46° with the C{sub 2} axis of the pyridine. The a-type spectra of HCCH—NC{sub 5}H{sub 5} and DCCD—NC{sub 5}H{sub 5} are doubled, suggesting the existence of a low lying pairmore » of tunneling states. This doubling persists in the spectra of HCCD—NC{sub 5}H{sub 5}, DCCH—NC{sub 5}H{sub 5}, indicating that the underlying motion does not involve interchange of the two hydrogens of the acetylene. Single {sup 13}C substitution in either the ortho- or meta-position of the pyridine eliminates the doubling and gives rise to separate sets of spectra that are well predicted by a bent geometry with the {sup 13}C on either the same side (“inner”) or the opposite side (“outer”) as the acetylene. High level ab initio calculations are presented which indicate a binding energy of 1.2 kcal/mol and a potential energy barrier of 44 cm{sup −1} in the C{sub 2v} configuration. Taken together, these results reveal a complex with a bent hydrogen bond and large amplitude rocking of the acetylene moiety. It is likely that the bent equilibrium structure arises from a competition between a weak hydrogen bond to the nitrogen (an n-pair hydrogen bond) and a secondary interaction between the ortho-hydrogens of the pyridine and the π electron density of the acetylene.« less

Acetylene fuels reductive dechlorination of TCE by Dehalococcoides/Pelobacter-containing microbial consortia

NASA Astrophysics Data System (ADS)

Oremland, R. S.; Mao, X.; Mahandra, C.; Baesman, S. M.; Gushgari, S.; Alvarez-Cohen, L.; Liu, T.

2015-12-01

Groundwater contamination by trichloroethene (TCE) poses a threat to health and leads to the generation of vinyl chloride (VC), a carcinogen. Dehalococcoides mccartyi is the only bacterium that can completely dechlorinate TCE to ethene (C2H4). Acetylene (C2H2) occurs in TCE-contaminated sites as a consequence of chemical degradation of TCE. Yet acetylene inhibits a variety of microbial processes including methanogesis and reductive dechlorination. Pelobacter acetylenicus and related species can metabolize acetylene via acetylene hydratase and acetaldehyde dismutatse thereby generating acetate and H2 as endproducts, which could serve as electron donor and carbon source for growth of D. mccartyi. We found that 1mM acetylene (aqueous) inhibits growth of D. mccartyi strain 195 on 0.3 mM TCE, but that the inhibition was removed after 12 days with the addition of an acetylene-utilizing isolate from San Francisco Bay, Pelobacter strain SFB93. TCE did not inhibit the growth of this Pelobacter at the concentrations tested (0.1-0.5 mM) and TCE was not consumed by strain SFB93. Co-cultures of strain 195 with strain SFB93 at 5% inoculation were established in 120 mL serum bottles containing 40 mL defined medium. TCE was supplied at a liquid concentration of 0.1 mM, with 0.1 mM acetylene and N2/CO2 (90:10 v/v) headspace at 34 °C. Co-cultures were subsequently transferred (5% vol/vol inoculation) to generate subcultures after 20 μmol TCE was reduced to VC and 36 μmol acetylene was depleted. Aqueous H2 ranged from 114 to 217 nM during TCE-dechlorination, and the cell yield of strain 195 was 3.7 ±0.3 × 107 cells μmol-1 Cl- released. In a D. mccartyi-containing enrichment culture (ANAS) under the same conditions as above, it was found that inhibition of dechlorination by acetylene was reversed after 19 days by adding SFB93. Thus we showed that a co-culture of Pelobacter SFB93 and D. mccartyi 195 could be maintained with C2H2 as the electron donor and carbon source while TCE served as the electron acceptor. Inhibition by C2H2 of reductive dechlorination in both the D. mccartyi isolate and the enrichment culture ANAS were observed, but the inhibition was eliminated by adding Pelobacter SFB93 to the cultures. These results will help facilitate the optimization of TCE-bioremediation at contaminated sites containing both TCE and C2H2.

Scaling relation for high-temperature biodiesel surrogate ignition delay times

DOE PAGES

Campbell, Matthew F.; Davidson, David F.; Hanson, Ronald K.

2015-10-11

High-temperature Arrhenius ignition delay time correlations are useful for revealing the underlying parameter dependencies of combustion models, for simplifying and optimizing combustion mechanisms for use in engine simulations, for scaling experimental data to new conditions for comparison purposes, and for guiding in experimental design. Here, we have developed a scaling relationship for Fatty Acid Methyl Ester (FAME) ignition time data taken at high temperatures in 4%O 2/Ar mixtures behind reflected shocks using an aerosol shock tube: τ ign [ms] = 2.24 x 10 -6 [ms] (P [atm]) -.41 (more » $$\\phi$$) 0.30(C n) -.61 x exp $$ \\left(\\frac{37.1 [kcal/mol]}{\\hat{R}_u [kcal / mol K] T [K]}\\right) $$ In addition, we have combined our ignition delay time data for methyl decanoate, methyl palmitate, methyl oleate, and methyl linoleate with other experimental results in the literature in order to derive fuel-specific oxygen-mole-fraction scaling parameters for these surrogates. In conclusion, in this article, we discuss the significance of the parameter values, compare our correlation to others found in the literature for different classes of fuels, and contrast the above expression’s performance with correlations obtained using leading FAME kinetic models in 4%O 2/Ar mixtures.« less

Supramolecule-to-Supramolecule Transformations of Coordination-Driven Self-Assembled Polygons

PubMed Central

Zhao, Liang; Northrop, Brian H.; Stang, Peter J.

2009-01-01

Two types of supramolecular transformations, wherein a self-assembled Pt(II)-pyridyl metal-organic polygon is controllably converted into an alternative polygon, have been achieved through the reaction between cobalt carbonyl and the acetylene moiety of a dipyridyl donor ligand. A [6+6] hexagon is transformed into two [3+3] hexagons and a triangle-square mixture is converted into [2+2] rhomboids. 1H and 31P NMR spectra are used to track the transformation process and evaluate the yield of new self-assembled polygons. Such transformed species are identified by electrospray ionization (ESI) mass spectrometry. This new kind of supramolecule-to-supramolecule transformations provides a viable means for constructing, and then converting, new self-assembled polygons. PMID:18702485

Organic matter in the Saturn system

NASA Technical Reports Server (NTRS)

Sagan, C.; Khare, B. N.; Lewis, J. S.

1984-01-01

Theoretical and experimental predictions of the formation (and outgassing) of organic molecules in the outer solar system are compared with Voyager IRIS spectral data for the Titan atmosphere. The organic molecules of Titan are of interest because the species and processes within the atmosphere of that moon may have had analogs in the early earth atmosphere 4 Gyr ago. The spacecraft data confirmed the presence of alkanes, ethane, propane, ethylene, alkynes, acetylene, butadiene, methylacetylene, nitriles, hydrogen cyanide, cyanoacetylene, and cyanogen, all heavier than the dominant CH4. Experimental simulation of the effects of UV photolysis, alpha and gamma ray irradiation, electrical discharges and proton and electron bombardment of similar gas mixtures has shown the best promise for modeling the reactions producing the Titan atmosphere chemicals.

Pyrolysis and Matrix-Isolation FTIR of Acetoin

NASA Astrophysics Data System (ADS)

Cole, Sarah; Ellis, Martha; Sowards, John; McCunn, Laura R.

2017-06-01

Acetoin, CH_3C(O)CH(OH)CH_3, is an additive used in foods and cigarettes as well as a common component of biomass pyrolysate during the production of biofuels, yet little is known about its thermal decomposition mechanism. In order to identify thermal decomposition products of acetoin, a gas-phase mixture of approximately 0.3% acetoin in argon was subject to pyrolysis in a resistively heated SiC microtubular reactor at 1100-1500 K. Matrix-isolation FTIR spectroscopy was used to identify pyrolysis products. Many products were observed in analysis of the spectra, including acetylene, propyne, ethylene, and vinyl alcohol. These results provide clues to the overall mechanism of thermal decomposition and are important for predicting emissions from many industrial and residential processes.

DETERMINATION OF 2-METHYL TETROLS AND 2-METHYLGLYCERIC ACID IN SECONDARY ORGANIC AEROSOL FROM LABORATORY IRRADIATED ISOPRENE/NO X/SO 2/AIR MIXTURES

EPA Science Inventory

This presentation addresses recent work performed at EPA to evaluate the potential for the photooxidation of isoprene to produce secondary organic aerosol. Analysis of the samples for methyl tetrols and 2-methylglyceric acid were performed at EPA and the University of Antwerp. T...

A PHYSIOLOGICALLY BASED PHARMACOKINETIC/PHARMACODYNAMIC (PBPK/PD) MODEL FOR ESTIMATION OF CUMULATIVE RISK FROM EXPOSURE TO THREE N-METHYL CARBAMATES: CARBARYL, ALDICARB, AND CARBOFURAN

EPA Science Inventory

A physiologically-based pharmacokinetic (PBPK) model for a mixture of N-methyl carbamate pesticides was developed based on single chemical models. The model was used to compare urinary metabolite concentrations to levels from National Health and Nutrition Examination Survey (NHA...

Acetylenes and dichloroanisoles from Psathyrella scobinacea.

PubMed

Taha, A A

2000-12-01

The Et2O extract from Psathyrella scobinacea culture fluids contained three new acetylenic alcohols: deca-5,7,9-triynol, (-)hepta-4,6-diyne-2,3-diol, and (-)hept-cis 4-en-6-yne-2,3-diol; two known dichloroanisoles: 3,5-dichloro-4-methoxybenzaldehyde and 3,5-dichloro-4-methoxybenzyl alcohol; and three known acetylenic acids: octa-2,4,6-triynoic acid, dec-trans-2-ene-4,6,8-triynoic acid and its cis-isomer.

NON-ADDITIVE DNA-DAMAGING EFFECTS OF GENOTOXINS IN MIXTURE: 3. MUTAGENICITY OF METHYL-NITROSO-UREA/ACETYLAMINOFLUORENE MIXTURES AND DNA REPAIR IN SALMONELLA. (R825809)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Process for the separation of components from gas mixtures

DOEpatents

Merriman, J.R.; Pashley, J.H.; Stephenson, M.J.; Dunthorn, D.I.

1973-10-01

A process for the removal, from gaseous mixtures of a desired component selected from oxygen, iodine, methyl iodide, and lower oxides of carbon, nitrogen, and sulfur is described. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatmospheric pressure to preferentially absorb the desired component in the fluorocarbon. Unabsorbed constituents of the gaseous mixture are withdrawn from the absorption zone. Liquid fluorocarbon enriched in the desired component is withdrawn separately from the zone, following which the desired component is recovered from the fluorocarbon absorbent. (Official Gazette)

Steric control of the asymmetric synthesis of N-substituted 2-methyl-4-piperidones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grishina, G.V.; Potapov, V.M.; Abdulganeeva, S.A.

Transmission of the iodomethylate of 1,2-dimethyl-4-piperidone by (S)-sec-butylamine gives 1-(S-sec-butyl)-2S-methyl-4-piperidone in 33% optical yield while transamination by (S)-1-methyl-2-phenylethylamine gives a 1:1 diastereomeric mixture of 1-(1-methyl-2-phenylethyl)-2-methyl-4-piperidone. The decrease in the optical yield is related to the facile opening of the piperidone ring at the C-N bond with subsequent recyclization. The /sup 13/C NMR data indicate that all the diastereomers of the 4-piperidones obtained are in the chain conformation with predominantly equatorial orientation of the methyl group at C/sub (2)/. The chiral optical properties were studied and the absolution configurations of the 4-piperidones obtained were established.

RAIN REPELLENT

DTIC Science & Technology

COATINGS, *RAINDROPS, *SILANES, *ULTRASONIC RADIATION, ACIDS, AEROSOLS, ALKOXY RADICALS, ALKYL RADICALS, CHLORIDES, FILMS, FLUORIDES, GLASS, LIQUIDS...MATERIALS, METHYL RADICALS, MIXTURES, ORGANIC COMPOUNDS, SALTS, STABILITY, STORAGE, SURFACES

Intermediates in the Formation of Aromatics in Hydrocarbon Combustion

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

1994-01-01

The formation of the first benzene ring is believed to be the rate limiting step in soot formation. Two different mechanisms have been proposed for formation of cyclic C6 species. The first involves the reaction of two acetylenes to give CH2CHCCH (vinyl acetylene), the loss of a H to give CHCHCCH (n-C41-13) or CH2CCCH (iso-C4H3), and addition of another acetylene to n-C4H3, followed by ring closure to give phenyl radical. Miller and Melius argue that only n-C4H3 leads to phenyl radical and since iso-C4H3 is more stable than n-C4H3 this mechanism is unlikely. An alternative mechanism proposed by them is formation of benzene from the dimerization of two CH2CCH (propargyl) radicals (formed by the reaction of singlet methylene with C2H2). We report reaction pathways and accurate energetics (from CASSCF/internally contracted CI calculations) for the reactions of CH(pi-2) and CH2-1 with acetylene, the reaction of vinylidene with acetylene, and the reaction of n-C4H3 and iso-C4H3 with acetylene. These calculations identify two new reactive intermediates CHCHCH ( a A"-2 ground state in Cs symmetry; spin coupling is a doublet from three singly occupied orbitals) and CHCCH (B-3 ground state in C2 symmetry) from the reaction of CH with acetylene. These species dimerize with no barrier to form benzene and para-benzyne, respectively. CHCCH is proposed as a reactive intermediate which can add to benzene to give higher polynuclear aromatic hydrocarbons or fullerenes. The addition of a C3H2 unit releases two C-C bond energies and thus the resulting addition product contains sufficient energy to break several CH bonds leading to a reduction in the H to C ratio as the cluster size increases. It is found that iso-C4H3 adds to acetylene to initially give a fulvene radical but that this species rearranges to phenyl radical. Thus, the reaction of acetylene with iso-C4H3 does lead to phenyl radical and the cyclization pathway may also contribute to formation of the initial benzene ring.

Effects of Tetrafluoroborate and Bis(trifluoromethylsulfonyl)amide Anions on the Microscopic Structures of 1-Methyl-3-octylimidazolium-Based Ionic Liquids and Benzene Mixtures: A Multiple Approach by ATR-IR, NMR, and Femtosecond Raman-Induced Kerr Effect Spectroscopy.

PubMed

Shirota, Hideaki; Kakinuma, Shohei; Itoyama, Yu; Umecky, Tatsuya; Takamuku, Toshiyuki

2016-01-28

The microscopic aspects of the two series of mixtures of 1-methyl-3-octylimidazolium tetrafluoroborate ([MOIm][BF4])-benzene and 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)amide ([MOIm][NTf2])-benzene were investigated by several spectroscopic techniques such as attenuated total reflectance IR (ATR-IR), NMR, and fs-Raman-induced Kerr effect spectroscopy (fs-RIKES). All three different spectroscopic results indicate that the anions more strongly interact with the cations in the [MOIm][BF4]-benzene mixtures than in the [MOIm][NTf2]-benzene mixtures. This also explains the different miscibility features between the two mixture systems well. The xC6H6 dependences of the chemical shifts and the C-H out-of-plane bending mode of benzene are similar: the changes are large in the high benzene concentration (xC6H6 > ∼ 0.6) compared to the low benzene concentration. In contrast, the linear xC6H6 dependences of the first moments of the low-frequency spectra less than 200 cm(-1) were observed in both the [MOIm][BF4]-benzene and [MOIm][NTf2]-benzene systems. The difference in the xC6H6 dependent features between the chemical shifts and intramolecular vibrational mode and the intermolecular/interionic vibrational bands might come from the different probing space scales. The traces of the parallel aromatic ring structure and the T-shape structure were found in the ATR-IR and NMR experiments, but fs-RIKES did not observe a clear trace of the local structure. This might imply that the interactions between the imidazolium and benzene rings are not strong enough to librate the imidazolium and benzene rings together. The bulk properties, such as miscibility, density, viscosity, and surface tension, of the two ionic liquid-benzene mixture series were also compared to the microscopic aspects.

Synergistic and Antagonistic Mutation Responses of Human MCL-5 Cells to Mixtures of Benzo[a]pyrene and 2-Amino-1-Methyl-6-Phenylimidazo[4,5-b]pyridine: Dose-Related Variation in the Joint Effects of Common Dietary Carcinogens.

PubMed

David, Rhiannon; Ebbels, Timothy; Gooderham, Nigel

2016-01-01

Chemical carcinogens such as benzo[a]pyrene (BaP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) may contribute to the etiology of human diet-associated cancer. Individually, these compounds are genotoxic, but the consequences of exposure to mixtures of these chemicals have not been systematically examined. We determined the mutagenic response to mixtures of BaP and PhIP at concentrations relevant to human exposure (micromolar to subnanomolar). Human MCL-5 cells (metabolically competent) were exposed to BaP or PhIP individually or in mixtures. Mutagenicity was assessed at the thymidine kinase (TK) locus, CYP1A activity was determined by ethoxyresorufin-O-deethylase (EROD) activity and qRT-PCR, and cell cycle was measured by flow cytometry. Mixtures of BaP and PhIP produced dose responses different from those of the individual chemicals; we observed remarkably increased mutant frequency (MF) at lower concentrations of the mixtures (not mutagenic individually), and decreased MF at higher concentrations of the mixtures, than the calculated predicted additive MF of the individual chemicals. EROD activity and CYP1A1 mRNA levels were correlated with TK MF, supporting involvement of the CYP1A family in mutation. Moreover, a cell cycle G2/M phase block was observed at high-dose combinations, consistent with DNA damage sensing and repair. Mixtures of these genotoxic chemicals produced mutation responses that differed from those expected for the additive effects of the individual chemicals. The increase in MF for certain combinations of chemicals at low concentrations that were not genotoxic for the individual chemicals, as well as the nonmonotonic dose response, may be important for understanding the mutagenic potential of food and the etiology of diet-associated cancers. David R, Ebbels T, Gooderham N. 2016. Synergistic and antagonistic mutation responses of human MCL-5 cells to mixtures of benzo[a]pyrene and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine: dose-related variation in the joint effects of common dietary carcinogens. Environ Health Perspect 124:88-96; http://dx.doi.org/10.1289/ehp.1409557.

Synergistic and Antagonistic Mutation Responses of Human MCL-5 Cells to Mixtures of Benzo[a]pyrene and 2-Amino-1-Methyl-6-Phenylimidazo[4,5-b]pyridine: Dose-Related Variation in the Joint Effects of Common Dietary Carcinogens

PubMed Central

David, Rhiannon; Ebbels, Timothy; Gooderham, Nigel

2015-01-01

Background Chemical carcinogens such as benzo[a]pyrene (BaP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) may contribute to the etiology of human diet-associated cancer. Individually, these compounds are genotoxic, but the consequences of exposure to mixtures of these chemicals have not been systematically examined. Objectives We determined the mutagenic response to mixtures of BaP and PhIP at concentrations relevant to human exposure (micromolar to subnanomolar). Methods Human MCL-5 cells (metabolically competent) were exposed to BaP or PhIP individually or in mixtures. Mutagenicity was assessed at the thymidine kinase (TK) locus, CYP1A activity was determined by ethoxyresorufin-O-deethylase (EROD) activity and qRT-PCR, and cell cycle was measured by flow cytometry. Results Mixtures of BaP and PhIP produced dose responses different from those of the individual chemicals; we observed remarkably increased mutant frequency (MF) at lower concentrations of the mixtures (not mutagenic individually), and decreased MF at higher concentrations of the mixtures, than the calculated predicted additive MF of the individual chemicals. EROD activity and CYP1A1 mRNA levels were correlated with TK MF, supporting involvement of the CYP1A family in mutation. Moreover, a cell cycle G2/M phase block was observed at high-dose combinations, consistent with DNA damage sensing and repair. Conclusions Mixtures of these genotoxic chemicals produced mutation responses that differed from those expected for the additive effects of the individual chemicals. The increase in MF for certain combinations of chemicals at low concentrations that were not genotoxic for the individual chemicals, as well as the nonmonotonic dose response, may be important for understanding the mutagenic potential of food and the etiology of diet-associated cancers. Citation David R, Ebbels T, Gooderham N. 2016. Synergistic and antagonistic mutation responses of human MCL-5 cells to mixtures of benzo[a]pyrene and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine: dose-related variation in the joint effects of common dietary carcinogens. Environ Health Perspect 124:88–96; http://dx.doi.org/10.1289/ehp.1409557 PMID:26091049

Ab initio dynamics and photoionization mass spectrometry reveal ion-molecule pathways from ionized acetylene clusters to benzene cation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P.

The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion-molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (Cmore » 2H 2) n +, just like ionized acetylene clusters. The fragmentation products result from reactive ion- molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C 4H 4 + and C 6H 6 + structures solvated with one or more neutral acetylene molecules. Such species contain large amounts ( > 2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C 2H 2) n + isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C 6H 6 + isomers. Lastly, these results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM.« less

Ab initio dynamics and photoionization mass spectrometry reveal ion–molecule pathways from ionized acetylene clusters to benzene cation

PubMed Central

Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P.; Fang, Yigang; Kostko, Oleg

2017-01-01

The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion–molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (C2H2)n+, just like ionized acetylene clusters. The fragmentation products result from reactive ion–molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C4H4+ and C6H6+ structures solvated with one or more neutral acetylene molecules. Such species contain large amounts (>2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C2H2)n+ isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C6H6+ isomers. These results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM. PMID:28484019

Ab initio dynamics and photoionization mass spectrometry reveal ion-molecule pathways from ionized acetylene clusters to benzene cation.

PubMed

Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P; Fang, Yigang; Kostko, Oleg; Ahmed, Musahid; Head-Gordon, Martin

2017-05-23

The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion-molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (C 2 H 2 ) n + , just like ionized acetylene clusters. The fragmentation products result from reactive ion-molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C 4 H 4 + and C 6 H 6 + structures solvated with one or more neutral acetylene molecules. Such species contain large amounts (>2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C 2 H 2 ) n + isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C 6 H 6 + isomers. These results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM.

Ab initio dynamics and photoionization mass spectrometry reveal ion-molecule pathways from ionized acetylene clusters to benzene cation

DOE PAGES

Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P.; ...

2017-05-08

The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion-molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (Cmore » 2H 2) n +, just like ionized acetylene clusters. The fragmentation products result from reactive ion- molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C 4H 4 + and C 6H 6 + structures solvated with one or more neutral acetylene molecules. Such species contain large amounts ( > 2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C 2H 2) n + isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C 6H 6 + isomers. Lastly, these results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM.« less

A review of acetylene, ethylene and ethane molecular spectroscopy for planetary applications

NASA Technical Reports Server (NTRS)

Maguire, W. C.

1982-01-01

Spectroscopic work in acetylene, ethylene and ethane, are of particular interest since the Voyager IRIS observations of Jupiter. Acetylene and ethane but not ethylene were observed in the Jovian spectrum. Two fundamental bands of the observed gases are used to determine the spatial distribution of these hydrocarbons on Jupiter and to illuminate the photochemistry of these species. The 100 to 1000 cm region is discussed and selected examples of current laboratory work are given.

[Photodissociation of Acetylene and Acetone using Step-Scan Time-Resolved FTIR Emission Spectroscopy

NASA Technical Reports Server (NTRS)

McLaren, Ian A.; Wrobel, Jacek D.

1997-01-01

The photodissociation of acetylene and acetone was investigated as a function of added quenching gas pressures using step-scan time-resolved FTIR emission spectroscopy. Its main components consist of Bruker IFS88, step-scan Fourier Transform Infrared (FTIR) spectrometer coupled to a flow cell equipped with Welsh collection optics. Vibrationally excited C2H radicals were produced from the photodissociation of acetylene in the unfocused experiments. The infrared (IR) emission from these excited C2H radicals was investigated as a function of added argon pressure. Argon quenching rate constants for all C2H emission bands are of the order of 10(exp -13)cc/molecule.sec. Quenching of these radicals by acetylene is efficient, with a rate constant in the range of 10(exp -11) cc/molecule.sec. The relative intensity of the different C2H emission bands did not change with the increasing argon or acetylene pressure. However, the overall IR emission intensity decreased, for example, by more than 50% when the argon partial pressure was raised from 0.2 to 2 Torr at fixed precursor pressure of 160mTorr. These observations provide evidence for the formation of a metastable C2H2 species, which are collisionally quenched by argon or acetylene. Problems encountered in the course of the experimental work are also described.

Mixed, short rotation culture of red alder and black cottonwood: growth, coppicing, nitrogen fixation, and allelopathy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heilman, P.; Stettler, R.F.

1985-01-01

Alnus rubra seedlings were grown in a 1:1 mixture at a spacing of 1.2 x 1.2 m with 28 Populus clones (25 clones pf P. trichocarpa, 2 of P. deltoides x P. trichocarpa, and one P. deltoides x P. nigra) in a study established in W. Washington in March 1979. Trees were harvested at 4 yr old. At harvest, average heights were: pure Populus, 10.2 m; Populus in the mixed stand 11.0 m; and alder 8.4 m. Most Populus sprouted satisfactorily after harvest (6.6 shoots/plant when pure, 7.6 shoots/plant in the mixture), but alder sprouted poorly (3.6 shoots/plant). Above-ground biomassmore » at harvest was 15.9 t/ha p.a. for the mixture and 16.7 t/ha p.a. for pure Populus, although the mixture had been more productive at 2 yr. Nitrogenase activity (nitrogen fixation as measured by acetylene reduction) of alder declines in the 4th season; competition was the most important factor influencing this decline. Soil N content had no effect on fixation. A pot study showed that ground Populus leaf and litter material inhibited the growth of red alder seedlings, although soil collected from Populus plots had no effect. Results indicated that allelopathy is probably a minor factor under field conditions, at most, and that growing mixed stands may, on balance, be beneficial. 20 references.« less

High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8 μm

NASA Astrophysics Data System (ADS)

Sajid, M. B.; Javed, T.; Farooq, A.

2015-04-01

The mid-infrared wavelength region near 8 μm contains absorption bands of several molecules such as water vapor, hydrogen peroxide, nitrous oxide, methane and acetylene. A new laser absorption sensor based on the ν4 band of methane and the ν4+ν5 band of acetylene is reported for interference-free, time-resolved measurements under combustion-relevant conditions. A detailed line-selection procedure was used to identify optimum transitions. Methane and acetylene were measured at the line centers of Q12 (1303.5 cm-1) and P23 (1275.5 cm-1) transitions, respectively. High-temperature absorption cross sections of methane and acetylene were measured at peaks (on-line) and valleys (off-line) of the selected absorption transitions. The differential absorption strategy was employed to eliminate interference absorption from large hydrocarbons. Experiments were performed behind reflected shock waves over a temperature range of 1200-2200 K, between pressures of 1-4 atm. The diagnostics were then applied to measure the respective species time-history profiles during the shock-heated pyrolysis of n-pentane.

Mechanism of tungsten-dependent acetylene hydratase from quantum chemical calculations.

PubMed

Liao, Rong-Zhen; Yu, Jian-Guo; Himo, Fahmi

2010-12-28

Acetylene hydratase is a tungsten-dependent enzyme that catalyzes the nonredox hydration of acetylene to acetaldehyde. Density functional theory calculations are used to elucidate the reaction mechanism of this enzyme with a large model of the active site devised on the basis of the native X-ray crystal structure. Based on the calculations, we propose a new mechanism in which the acetylene substrate first displaces the W-coordinated water molecule, and then undergoes a nucleophilic attack by the water molecule assisted by an ionized Asp13 residue at the active site. This is followed by proton transfer from Asp13 to the newly formed vinyl anion intermediate. In the subsequent isomerization, Asp13 shuttles a proton from the hydroxyl group of the vinyl alcohol to the α-carbon. Asp13 is thus a key player in the mechanism, but also W is directly involved in the reaction by binding and activating acetylene and providing electrostatic stabilization to the transition states and intermediates. Several other mechanisms are also considered but the energetic barriers are found to be very high, ruling out these possibilities.

6-methyl-8-hexadecenoic acid: A novel fatty acid from the marine spongeDesmapsama anchorata.

PubMed

Carballeira, N M; Maldonado, M E

1988-07-01

The novel fatty acid 7-methyl-8-hexadecenoic (1) was identified in the marine spongeDesmapsama anchorata. Other interesting fatty acids identified were 14-methyl-8-hexadecenoic (2), better known through its methyl ester as one of the components of the sex attractant of the female dermestid beetle, and the saturated fatty acid 3-methylheptadecanoic (3), known to possess larvicidal activity. The main phospholipid fatty acids encountered inD. anchorata were palmitic (16∶0), behenic (22∶0) and 5,9-hexacosadienoic acid (26∶2), which together accounted for 50% of the total phospholipid fatty acid mixture.

Synthesis of novel E-2-chlorovinyltellurium compounds based on the stereospecific anti-addition of tellurium tetrachloride to acetylene.

PubMed

Musalova, Maria V; Potapov, Vladimir A; Amosova, Svetlana V

2012-05-15

The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyl)tellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl(3) under a pressure of acetylene of 10-15 atm, whereas the former product was formed in up to 72% yield in CCl(4) under a pressure of acetylene of 1-3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl) telluride, E,E-bis(2-chlorovinyl) ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl)-tellurium dibromide is described.

Research in acetylene containing monomers

NASA Technical Reports Server (NTRS)

Ogliaruso, M. A.

1976-01-01

The preparation of precursor bisbenzils with pendant acetylene linkages for use in the synthesis of new aromatic poly (phenyl quinoxalines) was investigated. Attempts to condense para, para prime-dibromo benzil and potassium acetylide in liquid ammonia and in toluene, to prepare 4-phenyl acetyl phenyl ether, 4-(paraacetylphenyl) acetyl phenyl ether, 4-phenyl acetyl-4 primeacetyl phenyl acetyl phenyl ether, the reaction of 4-phenyl acetyl phenyl ether with Villsmeier reagent to prepare 4-(beta-chloro cinnamaldehyde) phenyl ether, the reaction of 4-(para-acetyl phenyl) acetyl phenyl ether with Villsmeier reagent, and the oxidation of bibenzil to prepare benzil are described. The reactions of phenyl acetylene with oxidizing agent, of phenyl acetylene with bromine, of 1,1,2,2-tetrabromo ethyl benzene with zinc and with oxidizing agent are described.

40 CFR 799.5000 - Testing consent orders for substances and mixtures with Chemical Abstract Service Registry Numbers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Environmental Releases Report November 18, 1994. 112-35-6 Triethylene glycol monomethyl ether Health effects... Health effects November 23, 1993. 994-05-8 Tertiary-amyl methyl ether Health effects March 21, 1995. 1634-04-4 Methyl tert-butyl ether Health effects March 31, 1988. 2461-18-9 Lauryl glycidyl ether 1 Health...

In vitro study comparing the ability of mono-octanoin and mono-octanoin plus methyl tert-butyl ether to dissolve biliary stones.

PubMed

Tritapepe, R; Cesana, B

1996-01-01

This in vitro study compared the gallstone dissolution rates of mono-octanoin, mono-octanoin plus 10% distilled water, and mono-octanoin plus methyl tert-butyl ether 2:1. Sixteen stones were treated with each solvent at a slow perfusion rate of 3-4 ml/h and a rapid perfusion rate of 2.5 ml/30 min with 20-sec instillation/aspiration cycles, both with and without bile. The stones were weighed before, and 3, 6, 12 and 24 hrs after the start of treatment: the solvent was changed every 30 min. After 24 hrs of instillation/aspiration without bile, the mono-octanoin/methyl tert-butyl ether mixture reduced the weight of the stones by 93%, mono-octanoin plus water by 63%, and mono-octanoin alone by 52%; with bile, the figures were, respectively, 86%, 42% and 40%. The mono-octanoin/methyl tert-butyl ether mixture thus took approximately half the time needed by the other two preparations to dissolve the stones to the same extent, a finding which may be relevant for the clinical dissolution of bile duct stones.

Cholinesterase Inhibition and Depression of the Photic After Discharge of Flash Evoked Potentials Following Acute or Repeated Exposures to a Mixture of Carbaryl and Propoxur

EPA Science Inventory

While information exists regarding inhibition of cholinesterase (ChE) activity, little is known about neurophysiological changes produced by a mixture of N-methyl carbamate pesticides. Previously, we reported that acute treatment with propoxur or carbaryl decreased the duration o...

The photolysis of NH3 in the presence of substituted acetylenes - A possible source of oligomers and HCN on Jupiter

NASA Technical Reports Server (NTRS)

Ferris, James P.; Jacobson, Richard R.; Guillemin, Jean C.

1992-01-01

An NMR spectral study is presently conducted of NH3 photolysis in the presence of substituted acetylenes with NMR spectra and gas chromatography. Quantum yields and percentage conversions to products are reported. It is shown that acetylenic hydrocarbons generated during methane photolysis in Jupiter's stratosphere can react with radicals formed by NH3 photolysis to yield nonvolatile, yellow-brown polymers, alkylnitriles, and in due course, HCN, as observed on Jupiter.

Solvent effect on the synthesis of clarithromycin: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Duran, Dilek; Aviyente, Viktorya; Baysal, Canan

2004-02-01

Clarithromycin (6- O-methylerythromycin A) is a 14-membered macrolide antibiotic which is active in vitro against clinically important gram-positive and gram-negative bacteria. The selectivity of the methylation of the C-6 OH group is studied on erythromycin A derivatives. To understand the effect of the solvent on the methylation process, detailed molecular dynamics (MD) simulations are performed in pure DMSO, pure THF and DMSO:THF (1:1) mixture by using the anions at the C-6, C-11 and C-12 positions of 2',4''-[ O-bis(TMS)]erythromycin A 9-[ O-(dimethylthexylsilyl)oxime] under the assumption that the anions are stable on the sub-nanosecond time scale. The conformations of the anions are not affected by the presence of the solvent mixture. The radial distribution functions are computed for the distribution of different solvent molecules around the `O-' of the anions. At distances shorter than 5 Å, DMSO molecules are found to cluster around the C-11 anion, whereas the anion at the C-12 position is surrounded by the THF molecules. The anion at the C-6 position is not blocked by the solvent molecules. The results are consistent with the experimental finding that the methylation yield at the latter position is increased in the presence of a DMSO:THF (1:1) solvent mixture. Thus, the effect of the solvent in enhancing the yield during the synthesis is not by changing the conformational properties of the anions, but rather by creating a suitable environment for methylation at the C-6 position.

Simultaneous metabolism of chloro- and methyl-aromatic compounds by selected bacterial strains. Final report, 20 August 1991-19 August 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Focht, D.D.

Microorganisms are frequently able to degrade anthropogenic materials using pathways that evolved for the assimilation of related naturally-occurring compounds. Complications can arise, however, during the metabolism of mixtures when incompatible intermediates are formed from different components. The breakdown of chloro- and methyl-aromatics, for example, produces catechols which are oxidized differently: chlorocatechols are normally cleaved by ortho fission and methylcatechols by meta fission. If both systems act simultaneously, suicide substrates or dead-end metabolites are usually formed. Nevertheless, bacteria differ in their, ability to cope with such mixtures. A unique bacterium, Pseudomonas cepacia MB2 was isolated by selective enrichment on 2-methylbenzoate, yetmore » was also able to fortuitously utilize 3-chloro-2-methylbenzoate as a sole carbon source. This strain is unique in its ability to utilize an aromatic acid containing both a methyl and chloro substituent via the metafission pathway without the production of suicidal products.« less

Ion Conduction in Perfectly Aligned Block Copolymer-Ionic Liquid Mixtures

NASA Astrophysics Data System (ADS)

Choi, Jae-Hong; Elabd, Yossef A.; Winey, Karen I.

2011-03-01

Our earlier work to correlate the transport measurements in diblock copolymer-ionic liquid mixtures was limited by our bulk samples that have only partial alignment. Here, thin films with perfect alignment of lamellar microdomains from mixtures of a poly(methyl methacrylate- b -styrene) diblock copolymer and an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, have been studied. The morphologies will be characterized by cross-sectional transmission electron microscopy. Ion conduction will be presented within and through the thin film.

Acetylene around Jupiter Poles

NASA Image and Video Library

2010-12-29

This graphic shows the distribution of the organic molecule acetylene at the north and south poles of Jupiter, based on data obtained by NASA Cassini spacecraft in early January 2001. Movie is available at the Photojournal.

Sub-cycle steering of the deprotonation of acetylene by intense few-cycle mid-infrared laser fields.

PubMed

Li, H; Kling, Nora G; Gaumnitz, T; Burger, C; Siemering, R; Schötz, J; Liu, Q; Ban, L; Pertot, Y; Wu, J; Azzeer, A M; de Vivie-Riedle, R; Wörner, H J; Kling, M F

2017-06-26

Directional breaking of the C-H/C-D molecular bond is manipulated in acetylene (C 2 H 2 ) and deuterated acetylene (C 2 D 2 ) by waveform controlled few-cycle mid-infrared laser pulses with a central wavelength around 1.6 μm at an intensity of about 8 × 10 13 W/cm 2 . The directionality of the deprotonation of acetylene is controlled by changing the carrier-envelope phase (CEP). The CEP-control can be attributed to the laser-induced superposition of vibrational modes, which is sensitive to the sub-cycle evolution of the laser waveform. Our experiments and simulations indicate that near-resonant, intense mid-infrared pulses permit a higher degree of control of the directionality of the reaction compared to those obtained in near-infrared fields, in particular for the deuterated species.

Design and study on optic fiber sensor detection system

NASA Astrophysics Data System (ADS)

Jiang, Xuemei; Liu, Quan; Liang, Xiaoyu; Lin, Haiyan

2005-11-01

With the development of industry and agriculture, the environmental pollution becomes more and more serious. Various kinds of poisonous gas are the important pollution sources. Various kinds of poisonous gas, such as the carbon monoxide, sulfureted hydrogen, sulfur dioxide, methane, acetylene are threatening human normal life and production seriously especially today when industry and various kinds of manufacturing industries develop at full speed. The acetylene is a kind of gas with very lively chemical property, extremely apt to burn, resolve and explode, and it is great to destroy things among these poisonous gases. Comparing with other inflammable and explosive gas, the explosion range of the acetylene is heavier. Therefore carrying on monitoring acetylene pollution sources scene in real time, grasping the state of pollution taking place and development in time, have very important meanings. Aim at the above problems, a set of optical fiber detection system of acetylene gas based on the characteristic of spectrum absorption of acetylene is presented in this paper, which has reference channel and is for on-line and real-time detection. In order to eliminate the effect of other factors on measurement precision, the double light sources, double light paths and double cells are used in this system. Because of the use of double wavelength compensating method, this system can eliminate the disturbance in the optical paths, the problem of instability is solved and the measurement precision is greatly enhanced. Some experimental results are presented at the end of this paper.

Studying the internal ballistics of a combustion-driven potato cannon using high-speed video

NASA Astrophysics Data System (ADS)

Courtney, E. D. S.; Courtney, M. W.

2013-07-01

A potato cannon was designed to accommodate several different experimental propellants and have a transparent barrel so the movement of the projectile could be recorded on high-speed video (at 2000 frames per second). Five experimental propellants were tested: propane (C3H8), acetylene (C2H2), ethanol (C2H6O), methanol (CH4O) and butane (C4H10). The quantity of each experimental propellant was calculated to approximate a stoichometric mixture and considering the upper and lower flammability limits, which in turn were affected by the volume of the combustion chamber. Cylindrical projectiles were cut from raw potatoes so that there was an airtight fit, and each weighed 50 (± 0.5) g. For each trial, position as a function of time was determined via frame-by-frame analysis. Five trials were made for each experimental propellant and the results analyzed to compute velocity and acceleration as functions of time. Additional quantities, including force on the potato and the pressure applied to the potato, were also computed. For each experimental propellant average velocity versus barrel position curves were plotted. The most effective experimental propellant was defined as that which accelerated the potato to the highest muzzle velocity. The experimental propellant acetylene performed the best on average (138.1 m s-1), followed by methanol (48.2 m s-1), butane (34.6 m s-1), ethanol (33.3 m s-1) and propane (27.9 m s-1), respectively.

Diffusion of 4-methyl-pent-3-en-2-one (1); air (2)

NASA Astrophysics Data System (ADS)

Winkelmann, J.

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) 4-methyl-pent-3-en-2-one; (2) air

Weathering and chemical degradation of methyl eugenol and raspberry ketone solid dispensers for detection, monitoring and male annihilation of Bactrocera dorsalis and Bactrocera cucurbitae (Diptera: Tephritidae) in Hawaii

USDA-ARS?s Scientific Manuscript database

Solid male lure dispensers containing methyl eugenol (ME) and raspberry ketone (RK), or mixtures of the lures (ME + RK), and dimethyl dichloro-vinyl phosphate (DDVP) were evaluated in AWPM bucket or Jackson traps in commercial papaya (Carica papaya L.) orchards where both oriental fruit fly, Bactroc...

Method for producing fluorinated diamond-like carbon films

DOEpatents

Hakovirta, Marko J.; Nastasi, Michael A.; Lee, Deok-Hyung; He, Xiao-Ming

2003-06-03

Fluorinated, diamond-like carbon (F-DLC) films are produced by a pulsed, glow-discharge plasma immersion ion processing procedure. The pulsed, glow-discharge plasma was generated at a pressure of 1 Pa from an acetylene (C.sub.2 H.sub.2) and hexafluoroethane (C.sub.2 F.sub.6) gas mixture, and the fluorinated, diamond-like carbon films were deposited on silicon <100>substrates. The film hardness and wear resistance were found to be strongly dependent on the fluorine content incorporated into the coatings. The hardness of the F-DLC films was found to decrease considerably when the fluorine content in the coatings reached about 20%. The contact angle of water on the F-DLC coatings was found to increase with increasing film fluorine content and to saturate at a level characteristic of polytetrafluoroethylene.

A Computational Investigation of Sooting Limits of Spherical Diffusion Flames

NASA Technical Reports Server (NTRS)

Lecoustre, V. R.; Chao, B. H.; Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Axelbaum, R. L.

2007-01-01

Limiting conditions for soot particle inception in spherical diffusion flames were investigated numerically. The flames were modeled using a one-dimensional, time accurate diffusion flame code with detailed chemistry and transport and an optically thick radiation model. Seventeen normal and inverse flames were considered, covering a wide range of stoichiometric mixture fraction, adiabatic flame temperature, and residence time. These flames were previously observed to reach their sooting limits after 2 s of microgravity. Sooting-limit diffusion flames with residence times longer than 200 ms were found to have temperatures near 1190 K where C/O = 0.6, whereas flames with shorter residence times required increased temperatures. Acetylene was found to be a reasonable surrogate for soot precursor species in these flames, having peak mole fractions of about 0.01.

Initiation reactions in acetylene pyrolysis

DOE PAGES

Zador, Judit; Fellows, Madison D.; Miller, James A.

2017-05-10

In gas-phase combustion systems the interest in acetylene stems largely from its role in molecular weight growth processes. The consensus is that above 1500 K acetylene pyrolysis starts mainly with the homolytic fission of the C–H bond creating an ethynyl radical and an H atom. However, below ~1500 K this reaction is too slow to initiate the chain reaction. It has been hypothesized that instead of dissociation, self-reaction initiates this process. Nevertheless, rigorous theoretical or direct experimental evidence is lacking, to an extent that even the molecular mechanism is debated in the literature. In this work we use rigorous abmore » initio transition-state theory master equation methods to calculate pressure- and temperature-dependent rate coefficients for the association of two acetylene molecules and related reactions. We establish the role of vinylidene, the high-energy isomer of acetylene in this process, compare our results with available experimental data, and assess the competition between the first-order and second-order initiation steps. As a result, we also show the effect of the rapid isomerization among the participating wells and highlight the need for time-scale analysis when phenomenological rate coefficients are compared to observed time scales in certain experiments.« less

Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed (Lemnaceae) Mats

PubMed Central

Zuberer, D. A.

1982-01-01

Duckweed (Lemnaceae) mats in Texas and Florida were investigated, using the acetylene reduction assay, to determine whether nitrogen fixation occurred in these floating aquatic macrophyte communities. N2-fixing microorganisms were enumerated by plating or most-probable-number techniques, using appropriate N-free media. Results of the investigations indicated that substantial N2-fixation (C2H2) was associated with duckweed mats in Texas and Florida. Acetylene reduction values ranged from 1 to 18 μmol of C2H4 g (dry weight)−1 day−1 for samples incubated aerobically in light. Dark N2 fixation was always two- to fivefold lower. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (7 to 10 μM) reduced acetylene reduction to levels intermediate between light and dark incubation. Acetylene reduction was generally greatest for samples incubated anaerobically in the light. It was estimated that 15 to 20% of the N requirement of the duckweed could be supplied through biological nitrogen fixation. N2-fixing heterotrophic bacteria (105 cells g [wet weight]−1 and cyanobacteria (105 propagules g [wet weight]−1 were associated with the duckweed mats. Azotobacter sp. was not detected in these investigations. One diazotrophic isolate was classified as Klebsiella. PMID:16345992

Interstitial pneumonitis after acetylene welding: a case report.

PubMed

Brvar, Miran

2014-01-01

Acetylene is a colorless gas commonly used for welding. It acts mainly as a simple asphyxiant. In this paper, however, we present a patient who developed a severe interstitial pneumonitis after acetylene exposure during aluminum welding. A 44-year old man was welding with acetylene, argon and aluminum electrode sticks in a non-ventilated aluminum tank for 2 h. Four hours after welding dyspnea appeared and 22 h later he was admitted at the Emergency Department due to severe respiratory insufficiency with pO2 = 6.7 kPa. Chest X-ray showed diffuse interstitial infiltration. Pulmonary function and gas diffusion tests revealed a severe restriction (55% of predictive volume) and impaired diffusion capacity (47% of predicted capacity). Toxic interstitial pneumonitis was diagnosed and high-dose systemic corticosteroid methylprednisolone and inhalatory corticosteroid fluticasone therapy was started. Computed Tomography (CT) of the lungs showed a diffuse patchy ground-glass opacity with no signs of small airway disease associated with interstitial pneumonitis. Corticosteroid therapy was continued for the next 8 weeks gradually reducing the doses. The patient's follow-up did not show any deterioration of respiratory function. In conclusion, acetylene welding might result in severe toxic interstitial pneumonitis that improves after an early systemic and inhalatory corticosteroid therapy.

Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

PubMed Central

Jiang, Chuanxing; Yin, Nailiang; Yao, Yao; Shaymurat, Talgar; Zhou, Xiaoyan

2017-01-01

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–SnO2/rGO nanocomposite is a good candidate for constructing a low-temperature acetylene sensor. PMID:28927021

Synthesis and assignment of the absolute configuration of the anti-Helicobacter pylori agents CJ-12,954 and CJ-13,014.

PubMed

Brimble, Margaret A; Bryant, Christina J

2007-09-07

The synthesis of the spiroacetal-containing anti-Helicobacter pylori agents (3S,2''S,5''S,7''S)- (ent-CJ-12,954) and (3S,2''S,5''R,7''S)- (ent-CJ-13,014) has been carried out based on the convergent union of a 1:1 mixture of heterocycle-activated spiroacetal sulfones and with (3S)-phthalide aldehyde . The synthesis of the (3R)-diastereomers (3R,2''S,5''S,7''S)- and (3R,2''S,5''R,7''S)- was also undertaken in a similar manner by union of (3R)-phthalide aldehyde with a 1:1 mixture of spiroacetal sulfones and . Comparison of the (1)H and (13)C NMR data, optical rotations and HPLC retention times of the synthetic compounds (3S,2''S,5''S,7''S)- and (3S,2''S,5''R,7''S)- and the (3R)-diastereomers (3R,2''S,5''S,7''S)- and (3R,2''S,5''R,7''S)-, with the naturally occurring compounds, established that the synthetic isomers and were in fact enantiomeric to the natural products CJ-12,954 and CJ-13,014. The (2S,8S)-stereochemistry in protected dihydroxyketone , the precursor to the mixture of spiroacetal sulfones and was established via union of readily available (S)-acetylene with aldehyde in which the (4S)-stereochemistry was established via asymmetric allylation. Deprotection and cyclization of protected dihydroxyketone afforded an inseparable 1:1 mixture of spiroacetal alcohols and that were converted into a 1:1 inseparable mixture of spiroacetal sulfones and . Phthalide-aldehyde was prepared via intramolecular acylation of bromocarbamate in which the (3S)-stereochemistry was established via asymmetric CBS reduction of ketone .

Improved method for mutagenicity testing of gaseous compounds by using a gas sampling bag.

PubMed

Araki, A; Noguchi, T; Kato, F; Matsushima, T

1994-05-01

A simple and safety gas exposure method was developed using a gas sampling bag as an exposure vessel and a preparation vessel of diluted gas. The gas exposure conditions such as amount of S9 in the plate, volume of gas for the plate, amount of top agar, exposure period and exposure temperature were examined by mutagenicity testing of 1,3-butadiene using the gas sampling bag. Mutagenicity tests of 14 compounds and 1,3-butadiene on S. typhimurium TA98, TA100, TA1535 and TA1537, and E. coli WP2 uvrA were also examined by the developed gas exposure method. 1,3-Butadiene, propyne (methyl acetylene), monochlorodifluoromethane, ethylchloride, diborane and silane were mutagenic. 1-Butene, 2-butene, 2-methylpropene, methyl vinyl ether, trichlorofluoromethane, dichlorodifluoromethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, 1,1-difluoroethane and phosphine were not mutagenic on S. typhimurium TA98, TA100, TA1535 and TA1537, and E. coli WP2 uvrA with or without metabolic activation. These results were compatible with a previous report, and this developed method has the advantage that it can be tested easily and safely for combustible and self-combustible substances such as 1,3-butadiene and silane.

Fixation of tritium in a highly stable polymer form

DOEpatents

Steinberg, Meyer; Colombo, Peter; Pruzansky, Jacob

1977-01-01

A method for the fixation of tritium comprising reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix.

Effects of hydrolysis of milk glycerides on the antimutagenicity of a hexane extract of milk.

PubMed

Nadathur, S R; Zhou, L; Lowry, R R; Bakalinsky, A T

1998-03-01

Reconstituted nonfat dry milk was treated with different amounts of lipase from Pseudomonas fluorescens. Hexane extracts of treated milks were dissolved in dimethylsulfoxide and assayed for antimutagenicity using the Ames test (Salmonella typhimurium TA 100) against N-methyl, N'-nitro, N-nitrosoguanidine. Anti-N-methyl, N'-nitro, N-nitrosoguanidine activity increased significantly as the amount of added lipase increased. At the highest lipase concentration tested, activity increased 5-fold, suggesting that liberated fatty acids contributed to the increased antimutagenicity. The activities of mixtures of pure fatty acids on antimutagenesis were examined using the Ames test. At the lowest concentrations tested, mixtures of palmitic and stearic acids and mixtures of palmitic and isopalmitic acids exhibited greater activity than did the individual acids. At all doses tested, mixtures of the monoacylglycerides of palmitic and stearic acids exhibited the same activity as the individual components. Quantification of fatty acids in milk and yogurt by gas chromatography indicated a 2 to 20-fold greater content of free fatty acids in yogurt. The increase in free fatty acids may contribute to the increase in antimutagenicity of yogurt relative to that of milk.

Anti-Helicobacter pylori activity of derivatives of the phthalide-containing antibacterial agents spirolaxine methyl ether, CJ-12,954, CJ-13,013, CJ-13,102, CJ-13,104, CJ-13,108 and CJ-13,015.

PubMed

Radcliff, Fiona J; Fraser, John D; Wilson, Zoe E; Heapy, Amanda M; Robinson, James E; Bryant, Christina J; Flowers, Christopher L; Brimble, Margaret A

2008-06-01

The naturally occurring phthalide-containing antibiotics spirolaxine methyl ether, CJ-12,954, CJ-13,013, CJ-13,015, CJ-13,102, CJ-13,103, CJ-13,104 and CJ-13,108, have been reported to exhibit anti-H. pylori activity. However, the exact stereochemistry of spirolaxine methyl ether, CJ-12,954 or CJ-13,013, contributing to this observed activity has not been confirmed. The anti-H. pylori activity of several analogues of spirolaxine methyl ether, CJ-12,954 and CJ-13,013 of defined stereochemistry together with the anti-H. pylori activity of several indole analogues of the simpler phthalide-containing antibiotics CJ-13,102, CJ-13,104, CJ-13,108 and CJ-13,015 is reported herein. A 1:1 mixture of spiroacetals 5b and 6b in which the phthalide substituent exhibited (3R)-stereochemistry was sixty times more active than the corresponding 1:1 mixture of spiroacetals with (3S)-stereochemistry. Notably, the unnatural (2''S)-diastereomer of spirolaxine methyl ether exhibited more potent anti-H. pylori activity than the natural product spirolaxine methyl ether. The 4,6-dimethoxyindoles 9, 10, 11 and 13 were all found to be less active than their parent compounds 1, 2, 3 and 4, respectively. Chain-shortened 4,6-dimethoxyindole analogue 12 of CJ-13,108 3 and 4,6-dimethoxyindole-spiroacetal 13 exhibited weak anti-H. pylori activity thus providing future opportunity for drug discovery programs.

Zeolite/magnetite composites as catalysts on the Synthesis of Methyl Esters (MES) from cooking oil

NASA Astrophysics Data System (ADS)

Sriatun; Darmawan, Adi; Sriyanti; Cahyani, Wuri; Widyandari, Hendri

2018-05-01

The using of zeolite/magnetite composite as a catalyst for the synthesis of methyl esters (MES) of cooking oil has been performed. In this study the natural magnetite was extracted from the iron sand of Semarang marina beach and milled by high energy Milling (HEM) with ball: magnetite ratio: 1:1. The composites prepared from natural zeolite and natural magnetite with zeolite: magnetite ratio 1:1; 2:1; 3:1 and 4:1. Preparation of methyl ester was catalyzed by composite of zeolite/magnetite through transeserification reaction, it was studied on variation of catalyst concentration (w/v) 1%, 3%, 5% and 10% to feed volume. The reaction product are mixture of methyl Oleic (MES), methyl Palmitic (MES) and methyl Stearic (MES). Character product of this research include density, viscosity, acid number and iodine number has fulfilled to SNI standard 7182: 2015.

Ethane and acetylene abundances in the Jovian atmosphere

NASA Technical Reports Server (NTRS)

Tokunaga, A.; Knacke, R. F.; Owen, T.

1976-01-01

The paper reports spectra of Jupiter in the spectral region from 755 to 850 kaysers, which covers the nu-9 fundamental of ethane and contains lines from the R branch of the nu-5 fundamental of acetylene. The monochromatic absorption coefficient of the central Q branch of the nu-9 fundamental of ethane, which was determined in the laboratory, is applied in a radiative-transfer calculation to evaluate the ethane mixing ratio in the Jovian atmosphere; the present data are also used to place an upper limit on the acetylene mixing ratio. For the radiative-transfer calculation, emission intensity is computed for the region above the 0.02-atm level assuming both an isothermal inversion layer and a previously reported temperature profile. The resulting maximum mixing ratios consistent with the observations are 0.00003 for ethane and 7.5 by 10 to the -8th power for acetylene.

Rotation of a Single Acetylene Molecule on Cu(001) by Tunneling Electrons in STM

NASA Astrophysics Data System (ADS)

Shchadilova, Yulia E.; Tikhodeev, Sergei G.; Paulsson, Magnus; Ueba, Hiromu

2013-11-01

We study the elementary processes behind one of the pioneering works on scanning tunneling microscope controlled reactions of single molecules [Stipe et al., Phys. Rev. Lett. 81, 1263 (1998)]. Using the Keldysh-Green function approach for the vibrational generation rate in combination with density functional theory calculations to obtain realistic parameters we reproduce the experimental rotation rate of an acetylene molecule on a Cu(100) surface as a function of bias voltage and tunneling current. This combined approach allows us to identify the reaction coordinate mode of the acetylene rotation and its anharmonic coupling with the C-H stretch mode. We show that three different elementary processes, the excitation of C-H stretch, the overtone ladder climbing of the hindered rotational mode, and the combination band excitation together explain the rotation of the acetylene molecule on Cu(100).

Purification and characterization of acetylene hydratase of Pelobacter acetylenicus, a tungsten iron-sulfur protein.

PubMed

Rosner, B M; Schink, B

1995-10-01

Acetylene hydratase of the mesophilic fermenting bacterium Pelobacter acetylenicus catalyzes the hydration of acetylene to acetaldehyde. Growth of P. acetylenicus with acetylene and specific acetylene hydratase activity depended on tungstate or, to a lower degree, molybdate supply in the medium. The specific enzyme activity in cell extract was highest after growth in the presence of tungstate. Enzyme activity was stable even after prolonged storage of the cell extract or of the purified protein under air. However, enzyme activity could be measured only in the presence of a strong reducing agent such as titanium(III) citrate or dithionite. The enzyme was purified 240-fold by ammonium sulfate precipitation, anion-exchange chromatography, size exclusion chromatography, and a second anion-exchange chromatography step, with a yield of 36%. The protein was a monomer with an apparent molecular mass of 73 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was at pH 4.2. Per mol of enzyme, 4.8 mol of iron, 3.9 mol of acid-labile sulfur, and 0.4 mol of tungsten, but no molybdenum, were detected. The Km for acetylene as assayed in a coupled photometric test with yeast alcohol dehydrogenase and NADH was 14 microM, and the Vmax was 69 mumol.min-1.mg of protein-1. The optimum temperature for activity was 50 degrees C, and the apparent pH optimum was 6.0 to 6.5. The N-terminal amino acid sequence gave no indication of resemblance to any enzyme protein described so far.

Purification and characterization of acetylene hydratase of Pelobacter acetylenicus, a tungsten iron-sulfur protein.

PubMed Central

Rosner, B M; Schink, B

1995-01-01

Acetylene hydratase of the mesophilic fermenting bacterium Pelobacter acetylenicus catalyzes the hydration of acetylene to acetaldehyde. Growth of P. acetylenicus with acetylene and specific acetylene hydratase activity depended on tungstate or, to a lower degree, molybdate supply in the medium. The specific enzyme activity in cell extract was highest after growth in the presence of tungstate. Enzyme activity was stable even after prolonged storage of the cell extract or of the purified protein under air. However, enzyme activity could be measured only in the presence of a strong reducing agent such as titanium(III) citrate or dithionite. The enzyme was purified 240-fold by ammonium sulfate precipitation, anion-exchange chromatography, size exclusion chromatography, and a second anion-exchange chromatography step, with a yield of 36%. The protein was a monomer with an apparent molecular mass of 73 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was at pH 4.2. Per mol of enzyme, 4.8 mol of iron, 3.9 mol of acid-labile sulfur, and 0.4 mol of tungsten, but no molybdenum, were detected. The Km for acetylene as assayed in a coupled photometric test with yeast alcohol dehydrogenase and NADH was 14 microM, and the Vmax was 69 mumol.min-1.mg of protein-1. The optimum temperature for activity was 50 degrees C, and the apparent pH optimum was 6.0 to 6.5. The N-terminal amino acid sequence gave no indication of resemblance to any enzyme protein described so far. PMID:7592321

Solid-state flurbiprofen and methyl-β-cyclodextrin inclusion complexes prepared using a single-step, organic solvent-free supercritical fluid process.

PubMed

Rudrangi, Shashi Ravi Suman; Kaialy, Waseem; Ghori, Muhammad U; Trivedi, Vivek; Snowden, Martin J; Alexander, Bruce David

2016-07-01

The aim of this study was to enhance the apparent solubility and dissolution properties of flurbiprofen through inclusion complexation with cyclodextrins. Especially, the efficacy of supercritical fluid technology as a preparative technique for the preparation of flurbiprofen-methyl-β-cyclodextrin inclusion complexes was evaluated. The complexes were prepared by supercritical carbon dioxide processing and were evaluated by solubility, differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, practical yield, drug content estimation and in vitro dissolution studies. Computational molecular docking studies were conducted to study the possibility of molecular arrangement of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin. The studies support the formation of stable molecular inclusion complexes between the drug and cyclodextrin in a 1:1 stoichiometry. In vitro dissolution studies showed that the dissolution properties of flurbiprofen were significantly enhanced by the binary mixtures prepared by supercritical carbon dioxide processing. The amount of flurbiprofen dissolved into solution alone was very low with 1.11±0.09% dissolving at the end of 60min, while the binary mixtures processed by supercritical carbon dioxide at 45°C and 200bar released 99.39±2.34% of the drug at the end of 30min. All the binary mixtures processed by supercritical carbon dioxide at 45°C exhibited a drug release of more than 80% within the first 10min irrespective of the pressure employed. The study demonstrated the single step, organic solvent-free supercritical carbon dioxide process as a promising approach for the preparation of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin in solid-state. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of currently used pesticides and their mixtures on the function of thyroid hormone and aryl hydrocarbon receptor in cell culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghisari, Mandana; Long, Manhai; Tabbo, Agnese

Evidence suggest that exposure to pesticides can interfere with the endocrine system by multiple mechanisms. The endocrine disrupting potential of currently used pesticides in Denmark was analyzed as single compounds and in an equimolar mixture of 5 selected pesticides. The pesticides were previously analyzed for effects on the function of estrogen and androgen receptors, the aromatase enzyme and steroidogenesis in vitro. In this study, the effect on thyroid hormone (TH) function and aryl hydrocarbon receptor (AhR) transactivity was assessed using GH3 cell proliferation assay (T-screen) and AhR responsive luciferase reporter gene bioassay, respectively. Thirteen pesticides were analyzed as follows: 2-methyl-4-chlorophenoxyaceticmore » acid, terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb and its metabolite ethylene thiourea, cypermethrin, tau-fluvalinate, and malathion (currently banned in DK). In the T-screen, prothioconazole, malathion, tau-fluvalinate, cypermethrin, terbuthylazine and mancozeb significantly stimulated and bitertanol and propiconazole slightly reduced the GH3 cell proliferation. In the presence of triiodothyronine (T3), prothioconazole, tau-fluvalinate, propiconazole, cypermethrin and bitertanol significantly antagonized the T3-induced GH3 cell proliferation. Eleven of the tested pesticides agonized the AhR function, and bitertanol and prothioconazole inhibited the basal AhR activity. Bitertanol, propiconazole, prothioconazole and cypermethrin antagonized the TCDD-induced AhR transactivation at the highest tested concentration. The 5-component mixture had inducing effect but the combined effect could not be predicted due to the presence of bitertanol eliciting inhibitory effect. Upon removal of bitertanol from the mixture, the remaining four pesticides acted additively. In conclusion, our data suggest that pesticides currently used in Denmark can interfere with TH signaling and AhR function in vitro and might have the potential to cause endocrine disruption. - Highlights: • Endocrine disrupting (ED) potential of currently used pesticides were evaluated in cell culture. • Pesticides were analyzed for disruption of TH and aryl hydrocarbon receptor function. • 6 pesticides increased the GH3 cell proliferation, whereasfour antagonized the T3-induced cell growth. • 11 pesticides had agonistic effect on AhR and 4 antagonized the TCDD-induced AhR transactivation. • The five component mixture had inducing effect in both assays.« less

Iminopropadienones RN=C=C=C=O and bisiminopropadienes RN=C=C=C=NR: Matrix infrared spectra and anharmonic frequency calculations

NASA Astrophysics Data System (ADS)

Bégué, Didier; Baraille, Isabelle; Andersen, Heidi Gade; Wentrup, Curt

2013-10-01

Methyliminopropadienone MeN=C=C=C=O 1a was generated by flash vacuum thermolysis from four different precursors and isolated in solid argon. The matrix-isolation infrared spectrum is dominated by unusually strong anharmonic effects resulting in complex fine structure of the absorptions due to the NCCCO moiety in the 2200 cm-1 region. Doubling and tripling of the corresponding absorption bands are observed for phenyliminopropadienone PhN=C=C=C=O 1b and bis(phenylimino)propadiene PhN=C=C=C=NPh 9, respectively. Anharmonic vibrational frequency calculations allow the identification of a number of overtones and combination bands as the cause of the splittings for each molecule. This method constitutes an important tool for the characterization of reactive intermediates and unusual molecules by matrix-isolation infrared spectroscopy.

A Robust Unified Approach to Analyzing Methylation and Gene Expression Data

PubMed Central

Khalili, Abbas; Huang, Tim; Lin, Shili

2009-01-01

Microarray technology has made it possible to investigate expression levels, and more recently methylation signatures, of thousands of genes simultaneously, in a biological sample. Since more and more data from different biological systems or technological platforms are being generated at an incredible rate, there is an increasing need to develop statistical methods that are applicable to multiple data types and platforms. Motivated by such a need, a flexible finite mixture model that is applicable to methylation, gene expression, and potentially data from other biological systems, is proposed. Two major thrusts of this approach are to allow for a variable number of components in the mixture to capture non-biological variation and small biases, and to use a robust procedure for parameter estimation and probe classification. The method was applied to the analysis of methylation signatures of three breast cancer cell lines. It was also tested on three sets of expression microarray data to study its power and type I error rates. Comparison with a number of existing methods in the literature yielded very encouraging results; lower type I error rates and comparable/better power were achieved based on the limited study. Furthermore, the method also leads to more biologically interpretable results for the three breast cancer cell lines. PMID:20161265

Successive ratio subtraction coupled with constant multiplication spectrophotometric method for determination of hydroquinone in complex mixture with its degradation products, tretinoin and methyl paraben

NASA Astrophysics Data System (ADS)

Elghobashy, Mohamed R.; Bebawy, Lories I.; Shokry, Rafeek F.; Abbas, Samah S.

2016-03-01

A sensitive and selective stability-indicating successive ratio subtraction coupled with constant multiplication (SRS-CM) spectrophotometric method was studied and developed for the spectrum resolution of five component mixture without prior separation. The components were hydroquinone in combination with tretinoin, the polymer formed from hydroquinone alkali degradation, 1,4 benzoquinone and the preservative methyl paraben. The proposed method was used for their determination in their pure form and in pharmaceutical formulation. The zero order absorption spectra of hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben were determined at 293, 357.5, 245 and 255.2 nm, respectively. The calibration curves were linear over the concentration ranges of 4.00-46.00, 1.00-7.00, 0.60-5.20, and 1.00-7.00 μg mL- 1 for hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben, respectively. The pharmaceutical formulation was subjected to mild alkali condition and measured by this method resulting in the polymerization of hydroquinone and the formation of toxic 1,4 benzoquinone. The proposed method was validated according to ICH guidelines. The results obtained were statistically analyzed and compared with those obtained by applying the reported method.

Successive ratio subtraction coupled with constant multiplication spectrophotometric method for determination of hydroquinone in complex mixture with its degradation products, tretinoin and methyl paraben.

PubMed

Elghobashy, Mohamed R; Bebawy, Lories I; Shokry, Rafeek F; Abbas, Samah S

2016-03-15

A sensitive and selective stability-indicating successive ratio subtraction coupled with constant multiplication (SRS-CM) spectrophotometric method was studied and developed for the spectrum resolution of five component mixture without prior separation. The components were hydroquinone in combination with tretinoin, the polymer formed from hydroquinone alkali degradation, 1,4 benzoquinone and the preservative methyl paraben. The proposed method was used for their determination in their pure form and in pharmaceutical formulation. The zero order absorption spectra of hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben were determined at 293, 357.5, 245 and 255.2 nm, respectively. The calibration curves were linear over the concentration ranges of 4.00-46.00, 1.00-7.00, 0.60-5.20, and 1.00-7.00 μg mL(-1) for hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben, respectively. The pharmaceutical formulation was subjected to mild alkali condition and measured by this method resulting in the polymerization of hydroquinone and the formation of toxic 1,4 benzoquinone. The proposed method was validated according to ICH guidelines. The results obtained were statistically analyzed and compared with those obtained by applying the reported method. Copyright © 2015. Published by Elsevier B.V.

Inhibitory effect of betel quid on the volatility of methyl mercaptan.

PubMed

Wang, C K; Chen, S L; Wu, M G

2001-04-01

Betel quid, a popular natural masticatory in Taiwan, is mainly composed of fresh areca fruit, Piper betle (leaf or inflorescence), and slaked lime paste. People say that halitosis disappears during betel quid chewing. In this study, the removal of mouth odor during betel quid chewing was discussed by using a model system which measured its inhibition on the volatility of methyl mercaptan. Results showed that crude extracts of betel quid (the mixture of areca fruit, Piper betle, and slaked lime paste) and extracts of the mixture of areca fruit and slaked lime paste exhibited marked effects on the volatility of methyl mercaptan, and the inhibition function increased when increasing amounts of slaked lime paste were added. The same condition (increased inhibition) was also found by replacing the slaked lime paste with alkaline salts (calcium hydroxide, potassium hydroxide, or sodium hydroxide). Areca fruit, the major ingredient of betel quid, contained abundant phenolics. However, the crude phenolic extract of areca fruit did not show any inhibitory activity on the volatility of methyl mercaptan. Great inhibitory activity occurred only when the crude phenolic extract of areca fruit was treated with alkali. Further studies by using gel filtration determined that the effect probably came from the oxidative polymerization of phenolics of areca fruit after alkaline treatment.

Lithium Ion Electrolytes and Lithium Ion Cells With Good Low Temperature Performance

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V. (Inventor); Smart, Marshall C. (Inventor)

2014-01-01

There is provided in one embodiment of the invention an electrolyte for use in a lithium ion electrochemical cell. The electrolyte comprises a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), an ester cosolvent, and a lithium salt. The ester cosolvent comprises methyl propionate (MP), ethyl propionate (EP), methyl butyrate (MB), ethyl butyrate (EB), propyl butyrate (PB), or butyl butyrate (BB). The electrochemical cell operates in a temperature range of from about -60 C to about 60 C. In another embodiment there is provided a lithium ion electrochemical cell using the electrolyte of the invention.

Studies on mushroom flavours 2. Flavour compounds in coprinus comatus.

PubMed

Dijkstra, F Y; Wikén, T O

1976-01-01

In an aqueous extract of fruit bodies of Coprinus comatus 3-octanone, 3-octanol, 1-octen-3-ol, 1-octanol, 2-methyl-2-penten-4-olide, 1-dodecanol and caprylic acid were identified conclusively and n-butyric and isobutyric acids preliminarily. Amino-acids, nucleotides and sugars were also determined. A mixture of 37 compounds found in the extract had a stronger flavour than the natural extract. 3-Octanol, 1-octen-3-ol, 1-octanol and 2-methyl-2-penten-4-olide were the volatiles with the strongest flavour. Mass and IR spectra of 2-methyl-2-penten-4-olide are presented.

Lithium-Ion Electrolytes Containing Flame Retardant Additives for Increased Safety Characteristics

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V. (Inventor); Krause, Frederick Charles (Inventor); Smart, Marshall C. (Inventor); Prakash, Surya G. (Inventor); Smith, Kiah A. (Inventor)

2014-01-01

The invention discloses various embodiments of Li-ion electrolytes containing flame retardant additives that have delivered good performance over a wide temperature range, good cycle life characteristics, and improved safety characteristics, namely, reduced flammability. In one embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a fluorinated co-solvent, a flame retardant additive, and a lithium salt. In another embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a flame retardant additive, a solid electrolyte interface (SEI) film forming agent, and a lithium salt.

Composition of zeotropic mixtures having predefined temperature glide

DOEpatents

Mahmoud, Ahmad M.; Lee, Jaeseon; Luo, Dong

2015-05-26

A composition of a zeotropic mixture has a first chemical constituent and at least one second, different chemical constituent. The zeoptropic mixture has a temperature glide of 5.degree. C.-25.degree. C. with regard to its saturated vapor temperature and its saturated liquid temperature. The first chemical constituent is selected from 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane, methyl perfluoropropyl ether, 1,1,1,2,3,3-hexafluoropropane and 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone.

49 CFR 173.303 - Charging of cylinders with compressed gas in solution (acetylene).

Code of Federal Regulations, 2010 CFR

2010-10-01

... with acetylene must be successfully tested in accordance with CGA C-12. (b) Filling limits. For DOT... conform to ISO 3807-2 (IBR, see § 171.7 of this subchapter), have a homogeneous monolithic porous mass...

Matrix Isolation and ab initio study of the noncovalent complexes between formamide and acetylene.

PubMed

Mardyukov, Artur; Sánchez-García, Elsa; Sander, Wolfram

2009-02-12

Matrix isolation spectroscopy in combination with ab initio calculations is a powerful technique for the identification of weakly bound intermolecular complexes. Here, weak complexes between formamide and acetylene are studied, and three 1:1 complexes with binding energies of -2.96, -2.46, and -1.79 kcal/mol have been found at the MP2 level of theory (MP2/cc-pVTZ + ZPE + BSSE). The two most stable dimers A and B are identified in argon and nitrogen matrices by comparison between the experimental and calculated infrared frequencies. Both complexes are stabilized by the formamide C=O...HC acetylene and H...pi interactions. Large shifts have been observed experimentally for the C-H stretching vibrations of the acetylene molecule, in very good agreement with the calculated values. Eight 1:2 FMA-acetylene trimers (T-A to T-H) with binding energies between -5.44 and -2.62 kcal/mol (MP2/aug-cc-pVDZ + ZPE + BSSE) were calculated. The two most stable trimers T-A and T-B are very close in energy and have similar infrared spectra. Several weak bands that are in agreement with the calculated frequencies of the trimers T-A and T-B are observed under matrix isolation conditions. However, the differences are too small for a definitive assignment.

Association Mechanisms of Unsaturated C2 Hydrocarbons with Their Cations: Acetylene and Ethylene

NASA Technical Reports Server (NTRS)

Bera, Partha P.; Head-Gordon, Martin; Lee, Timothy J.

2013-01-01

The ion-molecule association mechanism of acetylene and ethylene with their cations is investigated by ab initio quantum chemical methods to understand the structures, association energies, and the vibrational and electronic spectra of the products. Stable puckered cyclic isomers are found as the result of first forming less stable linear and bridge isomers. The puckered cyclic complexes are calculated to be strongly bound, by 87, 35 and 56 kcal/mol for acetylene-acetylene cation, ethylene-ethylene cation and acetylene-ethylene cation, respectively. These stable complexes may be intermediates that participate in further association reactions. There are no association barriers, and no significant inter-conversion barriers, so the initial linear and bridge encounter complexes are unlikely to be observable. However, the energy gap between the bridged and cyclic puckered isomers greatly differs from complex to complex: it is 44 kcal/mol in C4H4 +, but only 6 kcal/mol in C4H8 +. The accurate CCSD(T) calculations summarized above are also compared against less computationally expensive MP2 and density functional theory (DFT) calculations for structures, relative energies, and vibrational spectra. Calculated vibrational spectra are compared against available experiments for cyclobutadiene cation. Electronic spectra are also calculated using time-dependent DFT.

Determination of Acylglycerols in Diesel Oils by GC

PubMed Central

Wawrzyniak, Rafał; Wasiak, Wiesław

2008-01-01

In many EU countries and outside the EU, besides the addition of pure methyl ester B-100 to diesel oil, mixtures of methyl esters are also added to fuel. To be used as fuel, methyl esters must meet certain requirements, one of which is a certain level of acylglycerols. The paper presents results of determination of acylglycerols in diesel oil dotted with fatty acid methyl esters. The compounds were determined by gas chromatography using a high-temperature capillary column DB-5HT, made by J&W, and 1,2,3-tricaproylglycerol as internal standard. The analytical method proposed permits not only determination of acylglycerols, but also differentiation if the FAME added originated from pure vegetation oil or used cooking oil. PMID:19696907

Field validation of sound mitigation models and air pollutant emission testing in support of missile motor disposal activities.

PubMed

McFarland, Michael J; Palmer, Glenn R; Kordich, Micheal M; Pollet, Dean A; Jensen, James A; Lindsay, Mitchell H

2005-08-01

The U.S. Department of Defense approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile motors as well as the destruction of obsolete or otherwise unusable intercontinental ballistic missile motors through open burn/open detonation (OB/ OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of hazardous air pollutants. Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 56,500 lbs without generating adverse noise levels within populated areas. These results suggest that, under appropriate conditions, missile motors of even larger NEW may be detonated without exceeding regulatory noise limits. In conjunction with collecting noise monitoring data, air quality data was collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion fixed gases, hazardous air pollutants, and chlorides were monitored during the 56,500-lb NEW detonation event. Comparison of field measurements to predictions generated from the U.S. Navy's energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fireball expanded from ground zero, organic compounds as well as carbon monoxide continued to oxidize as the hot gases reacted with ambient air. Hazardous air pollutant analysis of air samplers confirmed the presence of chloromethane, benzene, toluene, 1,2-propadiene, and 2-methyl-l-propene, whereas the absence of hydrogen chloride gas suggested that free chlorine is not generated during the combustion process.

A novel methylation derivatization method for δ(18)O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry.

PubMed

Lehmann, Marco M; Fischer, Maria; Blees, Jan; Zech, Michael; Siegwolf, Rolf T W; Saurer, Matthias

2016-01-15

The oxygen isotope ratio (δ(18)O) of carbohydrates derived from animals, plants, sediments, and soils provides important information about biochemical and physiological processes, past environmental conditions, and geographical origins, which are otherwise not available. Nowadays, δ(18)O analyses are often performed on carbohydrate bulk material, while compound-specific δ(18)O analyses remain challenging and methods for a wide range of individual carbohydrates are rare. To improve the δ(18)O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry (GC/Pyr-IRMS) we developed a new methylation derivatization method. Carbohydrates were fully methylated within 24 h in an easy-to-handle one-pot reaction in acetonitrile, using silver oxide as proton acceptor, methyl iodide as methyl group carrier, and dimethyl sulfide as catalyst. The precision of the method ranged between 0.12 and 1.09‰ for the δ(18)O values of various individual carbohydrates of different classes (mono-, di-, and trisaccharides, alditols), with an accuracy of a similar order of magnitude, despite high variation in peak areas. Based on the δ(18)O values of the main isomers, important monosaccharides such as glucose and fructose could also be precisely analyzed for the first time. We tested the method on standard mixtures, honey samples, and leaf carbohydrates extracted from Pinus sylvestris, showing that the method is also applicable to different carbohydrate mixtures. The new methylation method shows unrivalled accuracy and precision for δ(18)O analysis of various individual carbohydrates; it is fast and easy-to-handle, and may therefore find wide-spread application. Copyright © 2015 John Wiley & Sons, Ltd.

Direct Detection of C_2H_2 in Air and Human Breath by Cw-Crds

NASA Astrophysics Data System (ADS)

Schmidt, Florian M.; Vaittinen, Olavi; Metsälä, Markus; Halonen, Lauri

2010-06-01

Continuous wave cavity ring-down spectroscopy (cw-CRDS) is an established cavity-enhanced absorption technique that can provide the necessary sensitivity, selectivity and fast acquisition time for many applications involving the detection of trace species. We present a simple but highly sensitive cw-CRDS spectrometer based on an external cavity diode laser operating in the near-infrared region. This instrument allows us to directly detect acetylene (C_2H_2) mixing ratios in air with a detection limit of 120 parts per trillion by volume (pptv) measuring on a C_2H_2 absorption line at 6565.620 cm-1. Acetylene is a combustion product that is routinely used in environmental monitoring as a marker for anthropogenic emissions. In a recent work, the spectrometer was employed to measure the level of acetylene in indoor and outdoor air in Helsinki. Continuous flow measurements with high time resolution (one minute) revealed strong fluctuations in the acetylene mixing ratio in outdoor air during daytime. Due to its non-invasive nature and fast response time, the analysis of exhaled breath for medical diagnostics is an excellent and straightforward alternative to methods using urine or blood samples. In an ongoing study, the cw-CRDS instrument is used to establish the baseline level of acetylene in the breath of the healthy population. An elevated amount of acetylene in breath could indicate exposure to combustion exhausts or other volatile organic compound (VOC) rich sources. The latest results of this investigation will be presented. F. M. Schmidt, O. Vaittinen, M. Metsälä, P. Kraus and L. Halonen, submitted for publication in Appl. Phys. B.

Soot Surface Growth in Laminar Hydrocarbon/Air Diffusion Flames. Appendix J

NASA Technical Reports Server (NTRS)

El-Leathy, A. M.; Xu, F.; Kim, C. H.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

2003-01-01

The structure and soot surface growth properties of round laminar jet diffusion flames were studied experimentally. Measurements were made along the axes of ethylene-, propylene-propane- and acetylene-benzene-fueled flames burning in coflowing air at atmospheric pressure with the reactants at normal temperature. The measurements included soot structure, soot concentrations, soot temperatures, major gas species concentrations, some radial species (H, OH and 0) concentrations, and gas velocities. These measurements yielded the local flame properties that are thought to affect soot surface growth as well as local soot surface growth rates. When present results were combined with similar earlier observations of acetylene-fueled laminar jet diffusion flames, the results suggested that soot surface growth involved decomposition of the original fuel to form acetylene and H, which were the main reactants for soot surface growth, and that the main effect of the parent fuel on soot surface growth involved its yield of acetylene and H for present test conditions. Thus, as the distance increased along the axes of the flames, soot formation (which was dominated by soot surface growth) began near the cool core of the flow once acetylene and H appeared together and ended near the flame sheet when acetylene disappeared. Species mainly responsible for soot oxidation - OH and 02 were present throughout the soot formation region so that soot surface growth and oxidation proceeded at the same time. Present measurements of soot surface growth rates (corrected for soot surface oxidation) in laminar jet diffusion flames were consistent with earlier measurements of soot surface growth rates in laminar premixed flames and exhibited good agreement with existing Hydrogen-Abstraction/Carbon-Addition (HACA) soot surface growth mechanisms in the literature with steric factors in these mechanisms having values on the order of unity, as anticipated.

Soot Surface Growth in Laminar Hydrocarbon/Air Diffusion Flames. Appendix B

NASA Technical Reports Server (NTRS)

El-Leathy, A. M.; Xu, F.; Kim, C. H.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

2001-01-01

The structure and soot surface growth properties of round laminar jet diffusion flames were studied experimentally. Measurements were made along the axes of ethylene-, propylene-propane- and acetylene-benzene-fueled flames burning in coflowing air at atmospheric pressure with the reactants at normal temperature. The measurements included soot structure, soot concentrations, soot temperatures, major gas species concentrations, some radial species (H, OH and O) concentrations, and gas velocities. These measurements yielded the local flame properties that are thought to affect soot surface growth as well as local soot surface growth rates. When present results were combined with similar earlier observations of acetylene-fueled laminar jet diffusion flames, the results suggested that soot surface growth involved decomposition of the original fuel to form acetylene and H, which were the main reactants for soot surface growth, and that the main effect of the parent fuel on soot surface growth involved its yield of acetylene and H for present test conditions. Thus, as the distance increased along the axes of the flames, soot formation (which was dominated by soot surface growth) began near the cool core of the flow once acetylene and H appeared together and ended near the flame sheet when acetylene disappeared. Species mainly responsible for soot oxidation - OH and O2 were present throughout the soot formation region so that soot surface growth and oxidation proceeded at the same time. Present measurements of soot surface growth rates (corrected for soot surface oxidation) in laminar jet diffusion flames were consistent with earlier measurements of soot surface growth rates in laminar premixed flames and exhibited good agreement with existing Hydrogen-Abstraction/Carbon-Addition (HACA) soot surface growth mechanisms in the literature with steric factors in these mechanisms having values on the order of unity, as anticipated.

Acetylene adsorption on δ-MoC(001), TiC(001) and ZrC(001) surfaces: A comprehensive periodic DFT study

DOE PAGES

Jimenez-Orozco, Carlos; Florez, Elizabeth; Moreno, Andres; ...

2016-12-06

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. It was found that the bonding of acetylene was significantly affected by the electronic and structural properties of the carbide surfaces. The adsorbate interacted with metal and/or carbon sites of the carbide. 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). Adsorption energies, charge density difference plotsmore » and Mulliken charges suggested that the binding of the hydrocarbon to the surface had both ionic and covalent contributions. 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). The obtained results suggest that the δ-MoC(001) surface is expected to have the best performance in selective hydrogenation reactions to convert alkynes into alkenes. Another advantage of δ-MoC(001) is that, after C 2H 2 adsorption, surface carbon sites remain available, which are necessary for H 2 dissociation. Furthermore, these sites were occupied when C 2H 2 was adsorbed on TiC(001) and ZrC(001), limiting their application in the hydrogenation of alkynes.« less

Effects of specific inhibitors on anammox and denitrification in marine sediments.

PubMed

Jensen, Marlene Mark; Thamdrup, Bo; Dalsgaard, Tage

2007-05-01

The effects of three metabolic inhibitors (acetylene, methanol, and allylthiourea [ATU]) on the pathways of N2 production were investigated by using short anoxic incubations of marine sediment with a 15N isotope technique. Acetylene inhibited ammonium oxidation through the anammox pathway as the oxidation rate decreased exponentially with increasing acetylene concentration; the rate decay constant was 0.10+/-0.02 microM-1, and there was 95% inhibition at approximately 30 microM. Nitrous oxide reduction, the final step of denitrification, was not sensitive to acetylene concentrations below 10 microM. However, nitrous oxide reduction was inhibited by higher concentrations, and the sensitivity was approximately one-half the sensitivity of anammox (decay constant, 0.049+/-0.004 microM-1; 95% inhibition at approximately 70 microM). Methanol specifically inhibited anammox with a decay constant of 0.79+/-0.12 mM-1, and thus 3 to 4 mM methanol was required for nearly complete inhibition. This level of methanol stimulated denitrification by approximately 50%. ATU did not have marked effects on the rates of anammox and denitrification. The profile of inhibitor effects on anammox agreed with the results of studies of the process in wastewater bioreactors, which confirmed the similarity between the anammox bacteria in bioreactors and natural environments. Acetylene and methanol can be used to separate anammox and denitrification, but the effects of these compounds on nitrification limits their use in studies of these processes in systems where nitrification is an important source of nitrate. The observed differential effects of acetylene and methanol on anammox and denitrification support our current understanding of the two main pathways of N2 production in marine sediments and the use of 15N isotope methods for their quantification.

Diffusion of cis-3-methyl-2-pent-2-enyl-cyclopent-2-enone (1); carbon dioxide (2)

NASA Astrophysics Data System (ADS)

Winkelmann, J.

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) cis-3-methyl-2-pent-2-enyl-cyclopent-2-enone; (2) carbon dioxide

Organic inorganic hybrid coating (poly(methyl methacrylate)/monodisperse silica)

NASA Astrophysics Data System (ADS)

Rubio, E.; Almaral, J.; Ramírez-Bon, R.; Castaño, V.; Rodríguez, V.

2005-04-01

Polymethylmethacrylate-silica hybrid coatings were prepared from methyl methacrylate and monodisperse colloidal silica prepared by the Stöber method. The surfaces of the spheres were successfully modified by chemical reaction with 3-(trimethoxysilyl) propyl methacrylate (TMSPM) to compatibilise the organic and inorganic components of the precursor solution mixture. The coatings were deposited by dip-coating on glass substrates. They result with good properties of homogeneity, optical transparence, hardness and adhesion.

Molecular weight growth in Titan's atmosphere: Branching pathways for the reaction of 1-propynyl radical (H 3CC≡C˙) with small alkenes and alkynes

DOE PAGES

Kirk, Benjamin B.; Savee, John D.; Trevitt, Adam J.; ...

2015-07-16

The reaction of small hydrocarbon radicals (i.e. ˙CN, ˙C 2H) with trace alkenes and alkynes is believed to play an important role in molecular weight growth and ultimately the formation of Titan's characteristic haze. Current photochemical models of Titan's atmosphere largely assume hydrogen atom abstraction or unimolecular hydrogen elimination reactions dominate the mechanism, in contrast to recent experiments that reveal significant alkyl radical loss pathways during reaction of ethynyl radical (˙C 2H) with alkenes and alkynes. In this study, the trend is explored for the case of a larger ethynyl radical analogue, the 1-propynyl radical (H3CC≡C˙), a likely product frommore » the high-energy photolysis of propyne in Titan's atmosphere. Using synchrotron vacuum ultraviolet photoionization mass spectrometry, product branching ratios are measured for the reactions of 1-propynyl radical with a suite of small alkenes (ethylene and propene) and alkynes (acetylene and d 4-propyne) at 4 Torr and 300 K. Reactions of 1-propynyl radical with acetylene and ethylene form single products, identified as penta-1,3-diyne and pent-1-en-3-yne, respectively. These products form by hydrogen atom loss from the radical-adduct intermediates. The reactions of 1-propynyl radical with d4-propyne and propene form products from both hydrogen atom and methyl loss, (–H = 27%, –CH 3 = 73%) and (–H = 14%, –CH 3 = 86%), respectively. Altogether, these results indicate that reactions of ethynyl radical analogues with alkenes and alkynes form significant quantities of products by alkyl loss channels, suggesting that current photochemical models of Titan over predict both hydrogen atom production as well as the efficiency of molecular weight growth in these reactions.« less

Molecular weight growth in Titan's atmosphere: branching pathways for the reaction of 1-propynyl radical (H3CC≡C˙) with small alkenes and alkynes.

PubMed

Kirk, Benjamin B; Savee, John D; Trevitt, Adam J; Osborn, David L; Wilson, Kevin R

2015-08-28

The reaction of small hydrocarbon radicals (i.e.˙CN, ˙C2H) with trace alkenes and alkynes is believed to play an important role in molecular weight growth and ultimately the formation of Titan's characteristic haze. Current photochemical models of Titan's atmosphere largely assume hydrogen atom abstraction or unimolecular hydrogen elimination reactions dominate the mechanism, in contrast to recent experiments that reveal significant alkyl radical loss pathways during reaction of ethynyl radical (˙C2H) with alkenes and alkynes. In this study, the trend is explored for the case of a larger ethynyl radical analogue, the 1-propynyl radical (H3CC[triple bond, length as m-dash]C˙), a likely product from the high-energy photolysis of propyne in Titan's atmosphere. Using synchrotron vacuum ultraviolet photoionization mass spectrometry, product branching ratios are measured for the reactions of 1-propynyl radical with a suite of small alkenes (ethylene and propene) and alkynes (acetylene and d4-propyne) at 4 Torr and 300 K. Reactions of 1-propynyl radical with acetylene and ethylene form single products, identified as penta-1,3-diyne and pent-1-en-3-yne, respectively. These products form by hydrogen atom loss from the radical-adduct intermediates. The reactions of 1-propynyl radical with d4-propyne and propene form products from both hydrogen atom and methyl loss, (-H = 27%, -CH3 = 73%) and (-H = 14%, -CH3 = 86%), respectively. Together, these results indicate that reactions of ethynyl radical analogues with alkenes and alkynes form significant quantities of products by alkyl loss channels, suggesting that current photochemical models of Titan over predict both hydrogen atom production as well as the efficiency of molecular weight growth in these reactions.

Molecular weight growth in Titan's atmosphere: Branching pathways for the reaction of 1-propynyl radical (H 3CC≡C˙) with small alkenes and alkynes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirk, Benjamin B.; Savee, John D.; Trevitt, Adam J.

The reaction of small hydrocarbon radicals (i.e. ˙CN, ˙C 2H) with trace alkenes and alkynes is believed to play an important role in molecular weight growth and ultimately the formation of Titan's characteristic haze. Current photochemical models of Titan's atmosphere largely assume hydrogen atom abstraction or unimolecular hydrogen elimination reactions dominate the mechanism, in contrast to recent experiments that reveal significant alkyl radical loss pathways during reaction of ethynyl radical (˙C 2H) with alkenes and alkynes. In this study, the trend is explored for the case of a larger ethynyl radical analogue, the 1-propynyl radical (H3CC≡C˙), a likely product frommore » the high-energy photolysis of propyne in Titan's atmosphere. Using synchrotron vacuum ultraviolet photoionization mass spectrometry, product branching ratios are measured for the reactions of 1-propynyl radical with a suite of small alkenes (ethylene and propene) and alkynes (acetylene and d 4-propyne) at 4 Torr and 300 K. Reactions of 1-propynyl radical with acetylene and ethylene form single products, identified as penta-1,3-diyne and pent-1-en-3-yne, respectively. These products form by hydrogen atom loss from the radical-adduct intermediates. The reactions of 1-propynyl radical with d4-propyne and propene form products from both hydrogen atom and methyl loss, (–H = 27%, –CH 3 = 73%) and (–H = 14%, –CH 3 = 86%), respectively. Altogether, these results indicate that reactions of ethynyl radical analogues with alkenes and alkynes form significant quantities of products by alkyl loss channels, suggesting that current photochemical models of Titan over predict both hydrogen atom production as well as the efficiency of molecular weight growth in these reactions.« less

Photographic laboratory studies of explosions.

NASA Technical Reports Server (NTRS)

Kamel, M. M.; Oppenheim, A. K.

1973-01-01

Description of a series of cinematographic studies of explosions made with a high-speed rotating-mirror streak camera which uses a high-frequency stroboscopic ruby laser as the light source. The results obtained mainly concern explosions initiated by focused laser irradiation from a pulsed neodymium laser in a detonating gas consisting essentially of an equimolar mixture of acetylene and oxygen at an initial pressure of 100 torr at room temperature. Among the most significant observations were observations of a spherical blast wave preceded by a Chapman-Jouguet detonation which is stabilized immediately after initiation, the merging of a spherical flame with a shock front of the blast wave in which the flame is propagating, the division of a spherical detonation front into a shock wave and flame, and the generation of shock waves by a network of spherical flames.

Microwave-assisted direct synthesis of butene from high-selectivity methane

NASA Astrophysics Data System (ADS)

Lu, Yi-heng; Li, Kang; Lu, Yu-wei

2017-12-01

Methane was directly converted to butene liquid fuel by microwave-induced non-oxidative catalytic dehydrogenation under 0.1-0.2 MPa. The results show that, under microwave heating in a two-stage fixed-bed reactor, in which nickel powder and NiOx-MoOy/SiO2 are used as the catalyst, the methane-hydrogen mixture is used as the raw material, with no acetylene detected. The methane conversion is more than 73.2%, and the selectivity of methane to butene is 99.0%. Increasing the hydrogen/methane feed volume ratio increases methane conversion and selectivity. Gas chromatography/electron impact ionization/mass spectrometry chromatographic analysis showed that the liquid fuel produced by methane dehydrogenation oligomerization contained 89.44% of butene, and the rest was acetic acid, ethanol, butenol and butyric acid, and the content was 1.0-3.0 wt%.

Measurements of admittances and characteristic combustion times of reactive gaseous propellant coaxial injectors

NASA Technical Reports Server (NTRS)

Janardan, B. A.; Daniel, B. R.; Zinn, B. T.

1979-01-01

The results of an experimental investigation that was concerned with the quantitative determination of the capabilities of combustion processes associated with coaxial injectors to amplify and sustain combustor oscillations was described. The driving provided by the combustion process was determined by employing the modified standing-wave method utilizing coaxial injectors and air-acetylene mixtures. Analyses of the measured data indicate that the investigated injectors are capable of initiating and amplifying combustion instabilities under favorable conditions of injector-combustion coupling and over certain frequency ranges. These frequency ranges and the frequency at which an injector's driving capacity is maximum are observed to depend upon the equivalence ratio, the pressure drop across the injector orifices and the number of injector elements. The characteristic combustion times of coaxial injectors were determined from steady state temperature measurements.

Soot formation in shock-tube pyrolysis and oxidation of vinylacetylene

NASA Technical Reports Server (NTRS)

Frenklach, M.; Yuan, T.; Ramachandra, M. K.

1990-01-01

Soot formation in vinylacetylene, and vinylacetylene-oxygen argon-diluted mixtures was studied behind reflected shock waves by monitoring the attenuation of a 632.8-nm He-Ne laser beam. The experiments were performed at temperatures of 1600-2500 K, pressures of 2.08-3.09 bar, and total carbon atom concentrations of (1.99-2.05) x 10 to the 17th atoms/cu cm. The experimental results obtained in pyrolysis of vinylacetylene are similar to those of acetylene, both in the order of magnitude of the soot yield and the shape of its temperature dependence. The addition of oxygen to vinylacetylene shifts the soot bell to lower temperature and, distinct from all other hydrocarbons studied in this laboratory, accelerates the production of soot with reaction time. The experimental results are interpreted in terms of possible chemical reaction.

Separation of Acetylene from Carbon Dioxide and Ethylene by a Water-Stable Microporous Metal-Organic Framework with Aligned Imidazolium Groups inside the Channels.

PubMed

Lee, Jaechul; Chuah, Chong Yang; Kim, Jaheon; Kim, Youngsuk; Ko, Nakeun; Seo, Younggyu; Kim, Kimoon; Bae, Tae Hyun; Lee, Eunsung

2018-04-24

Separation of acetylene from carbon dioxide and ethylene is challenging in view of their similar sizes and physical properties. Metal-organic frameworks (MOFs) in general are strong candidates for these separations owing to the presence of functional pore surfaces that can selectively capture a specific target molecule. Here, we report a novel 3D microporous cationic framework named JCM-1. This structure possesses imidazolium functional groups on the pore surfaces and pyrazolate as a metal binding group, which is well known to form strong metal-to-ligand bonds. The selective sorption of acetylene over carbon dioxide and ethylene in JCM-1 was successfully demonstrated by equilibrium gas adsorption analysis as well as dynamic breakthrough measurement. Furthermore, its excellent hydrolytic stability makes the separation processes highly recyclable without a substantial loss in acetylene uptake capacity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The electronic structure and second-order nonlinear optical properties of donor-acceptor acetylenes - A detailed investigation of structure-property relationships

NASA Technical Reports Server (NTRS)

Stiegman, A. E.; Graham, Eva; Khundkar, Lutfur R.; Perry, Joseph W.; Cheng, L.-T.; Perry, Kelly J.

1991-01-01

A series of donor-acceptor acetylene compounds was synthesized in which systematic changes in both the conjugation length and the donor-acceptor strength were made. The effect of these structural changes on the spectroscopic and electronic properties of the molecules and, ultimately, on the measured second-order molecular hyperpolarizabilities (beta) was investigated. It was found that increases in the donor-acceptor strength resulted in increases in the magnitude of beta. For this class of molecules, the increase is dominated by the energy of the intramolecular charge-transfer transition, while factors such as the ground to excited-state dipole moment change and the transition-moment integral are much less important. Increasing the conjugation length from one to two acetylene linkers did not result in an increase in the value of beta; however, beta increased sharply in going from two acetylenes to three. This increase is attributed to the superposition of several nearly isoenergetic excited states.

Pesticide and insect repellent mixture (permethrin and DEET) induces epigenetic transgenerational inheritance of disease and sperm epimutations.

PubMed

Manikkam, Mohan; Tracey, Rebecca; Guerrero-Bosagna, Carlos; Skinner, Michael K

2012-12-01

Environmental compounds are known to promote epigenetic transgenerational inheritance of disease. The current study was designed to determine if a "pesticide mixture" (pesticide permethrin and insect repellent N,N-diethyl-meta-toluamide, DEET) promotes epigenetic transgenerational inheritance of disease and associated DNA methylation epimutations in sperm. Gestating F0 generation female rats were exposed during fetal gonadal sex determination and the incidence of disease evaluated in F1 and F3 generations. There were significant increases in the incidence of total diseases in animals from pesticide lineage F1 and F3 generation animals. Pubertal abnormalities, testis disease, and ovarian disease (primordial follicle loss and polycystic ovarian disease) were increased in F3 generation animals. Analysis of the pesticide lineage F3 generation sperm epigenome identified 363 differential DNA methylation regions (DMR) termed epimutations. Observations demonstrate that a pesticide mixture (permethrin and DEET) can promote epigenetic transgenerational inheritance of adult onset disease and potential sperm epigenetic biomarkers for ancestral environmental exposures. Copyright © 2012 Elsevier Inc. All rights reserved.

Acetylene-based pathways for prebiotic evolution on Titan

NASA Astrophysics Data System (ADS)

Abbas, O.; Schulze-Makuch, D.

2002-11-01

Due to Titan's reducing atmosphere and lack of an ozone shield, ionizing radiation penetrates the atmosphere creating ions, radicals and electrons that are highly reactive producing versatile chemical species on Titan's surface. We propose that the catalytic hydrogenation of photochemically produced acetylene may be used as simple metabolic pathway by organisms at or near Titan's surface. While the acetylene may undergo this reaction, it can also undertake several other multi-step synthetic schemes that eventually lead to the production of amino acids or other biologically important molecules. Four model synthetic schemes will be described, and their relevance in relation to prebiotic evolution on Earth is discussed.

Identification of non-heme diiron proteins that catalyze triple bond and epoxy group formation.

PubMed

Lee, M; Lenman, M; Banaś, A; Bafor, M; Singh, S; Schweizer, M; Nilsson, R; Liljenberg, C; Dahlqvist, A; Gummeson, P O; Sjödahl, S; Green, A; Stymne, S

1998-05-08

Acetylenic bonds are present in more than 600 naturally occurring compounds. Plant enzymes that catalyze the formation of the Delta12 acetylenic bond in 9-octadecen-12-ynoic acid and the Delta12 epoxy group in 12,13-epoxy-9-octadecenoic acid were characterized, and two genes, similar in sequence, were cloned. When these complementary DNAs were expressed in Arabidopsis thaliana, the content of acetylenic or epoxidated fatty acids in the seeds increased from 0 to 25 or 15 percent, respectively. Both enzymes have characteristics similar to the membrane proteins containing non-heme iron that have histidine-rich motifs.

High temperature concrete composites containing organosiloxane crosslinked copolymers

DOEpatents

Zeldin, A.; Carciello, N.; Kukacka, L.; Fontana, J.

High temperature polymer concrete composites comprising about 10 to 30% by weight of a liquid monomer mixture is described. It consists essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures thereof. About 70 to 90% by weight of an inert inorganic filler system containing silica sand and portland cement, Fe/sub 2/O/sub 3/, carbon black or mixtures thereof. Optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobyutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides are used to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

Fire extinguishing tests -80 with methyl alcohol gasoline

NASA Astrophysics Data System (ADS)

Holmstedt, G.; Ryderman, A.; Carlsson, B.; Lennmalm, B.

1980-10-01

Large scale tests and laboratory experiments were carried out for estimating the extinguishing effectiveness of three alcohol resistant aqueous film forming foams (AFFF), two alcohol resistant fluoroprotein foams and two detergent foams in various poolfires: gasoline, isopropyl alcohol, acetone, methyl-ethyl ketone, methyl alcohol and M15 (a gasoline, methyl alcohol, isobutene mixture). The scaling down of large scale tests for developing a reliable laboratory method was especially examined. The tests were performed with semidirect foam application, in pools of 50, 11, 4, 0.6, and 0.25 sq m. Burning time, temperature distribution in the liquid, and thermal radiation were determined. An M15 fire can be extinguished with a detergent foam, but it is impossible to extinguish fires in polar solvents, such as methyl alcohol, acetone, and isopropyl alcohol with detergent foams, AFFF give the best results; and performances with small pools can hardly be correlated with results from large scale fires.

Forensic discrimination of vaginal epithelia by DNA methylation analysis through pyrosequencing.

PubMed

Antunes, Joana; Silva, Deborah S B S; Balamurugan, Kuppareddi; Duncan, George; Alho, Clarice S; McCord, Bruce

2016-10-01

The accurate identification of body fluids from crime scenes can aid in the discrimination between criminal and innocent intent. This research aimed to determine if the levels of DNA methylation in the locus PFN3A could be used to discriminate vaginal epithelia from other body fluids. In this work we bisulfite-modified and amplified DNA samples from blood, saliva, semen, and vaginal epithelia using primers for PFN3A. Through pyrosequencing we were able to show that vaginal epithelia present distinct methylation levels when compared to other body fluids. Mixtures of different body fluids present methylation values that correlate with single-source body fluid samples and the primers for PFN3A are specific for primates. This report successfully demonstrated that the analysis of methylation in the PFN3A locus can be used for vaginal epithelia discrimination in forensic samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A potential plant-derived antifungal acetylenic acid mediates its activity by interfering with fatty acid homeostasis

USDA-ARS?s Scientific Manuscript database

6-Nonadecynoic acid (6-NDA), a plant-derived acetylenic acid, exhibits strong inhibitory activity against the human fungal pathogens Candida albicans, Aspergillus fumigatus, and Trichophyton mentagrophytes. In the present study, transcriptional profiling coupled with mutant and biochemical analyses...

Synthesis of Spiro Indole-2-Ones Using Three Component Reaction of N-Alkylisatins and Triphenylphosphonium Intermediates.

PubMed

Moradi, Ali Varasteh

2017-01-01

A simple and efficient procedure is achieved for the synthesis of indole-2-one derivatives via three-component reaction of N-alkylisatin, activated acetylenic compounds and alkyl bromide in the presence of triphenylphosphine in water under two conditions; room temperature and microwave irradiation. All chemicals used in this work were prepared from Fluka (Buchs, Switzerland) and were used without further purification. N-alkylisatin were synthesized in the laboratory in the procedure that is reported in the literature. Electrothermal 9100 apparatus is employed for measuring of melting points of products. Elemental analyses for C, H, and N were performed with Heraeus CHN-O-Rapid analyzer. Mass spectra were recorded on a FINNIGAN-MAT 8430 spectrometer operating at an ionization potential of 70 eV. Measurement of IR spectra was performed by Shimadzu IR-460 spectrometer. 1H, and 13C NMR spectra were evaluated with a BRUKER DRX- 500 AVANCE spectrometer at 500.1 and 125.8 MHz, respectively. The results were demonstrated that simple mixing of N-alkylisatin, dialkyl acetylenedicarboxylate and alkyl bromides in the presence of triphenylphosphine by using of microwave condition is the efficient method for preparation of indole derivatives in good yields. In the optimized reaction conditions, water is solvent and temperature of the mixture of reaction is 80 oC. In this study, the reaction of activated acetylenic compounds with N-alkylisatin and alkyl bromide in the presence of triphenylphosphine is investigated which is led to a facile synthesis of some functionalized indoles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

An Ideal Molecular Sieve for Acetylene Removal from Ethylene with Record Selectivity and Productivity.

PubMed

Li, Bin; Cui, Xili; O'Nolan, Daniel; Wen, Hui-Min; Jiang, Mengdie; Krishna, Rajamani; Wu, Hui; Lin, Rui-Biao; Chen, Yu-Sheng; Yuan, Daqiang; Xing, Huabin; Zhou, Wei; Ren, Qilong; Qian, Guodong; Zaworotko, Michael J; Chen, Banglin

2017-12-01

Realization of ideal molecular sieves, in which the larger gas molecules are completely blocked without sacrificing high adsorption capacities of the preferred smaller gas molecules, can significantly reduce energy costs for gas separation and purification and thus facilitate a possible technological transformation from the traditional energy-intensive cryogenic distillation to the energy-efficient, adsorbent-based separation and purification in the future. Although extensive research endeavors are pursued to target ideal molecular sieves among diverse porous materials, over the past several decades, ideal molecular sieves for the separation and purification of light hydrocarbons are rarely realized. Herein, an ideal porous material, SIFSIX-14-Cu-i (also termed as UTSA-200), is reported with ultrafine tuning of pore size (3.4 Å) to effectively block ethylene (C 2 H 4 ) molecules but to take up a record-high amount of acetylene (C 2 H 2 , 58 cm 3 cm -3 under 0.01 bar and 298 K). The material therefore sets up new benchmarks for both the adsorption capacity and selectivity, and thus provides a record purification capacity for the removal of trace C 2 H 2 from C 2 H 4 with 1.18 mmol g -1 C 2 H 2 uptake capacity from a 1/99 C 2 H 2 /C 2 H 4 mixture to produce 99.9999% pure C 2 H 4 (much higher than the acceptable purity of 99.996% for polymer-grade C 2 H 4 ), as demonstrated by experimental breakthrough curves. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular Affinity Chromatography for Methylation-Targeted Proteomics.

PubMed

Garnett, Graham A E; Starke, Melissa J; Shaurya, Alok; Li, Janessa; Hof, Fraser

2016-04-05

Proteome-wide studies of post-translationally methylated species using mass spectrometry are complicated by high sample diversity, competition for ionization among peptides, and mass redundancies. Antibody-based enrichment has powered methylation proteomics until now, but the reliability, pan-specificity, polyclonal nature, and stability of the available pan-specific antibodies are problematic and do not provide a standard, reliable platform for investigators. We have invented an anionic supramolecular host that can form host-guest complexes selectively with methyllysine-containing peptides and used it to create a methylysine-affinity column. The column resolves peptides on the basis of methylation-a feat impossible with a comparable commercial cation-exchange column. A proteolyzed nuclear extract was separated on the methyl-affinity column prior to standard proteomics analysis. This experiment demonstrates that such chemical methyl-affinity columns are capable of enriching and improving the analysis of methyllysine residues from complex protein mixtures. We discuss the importance of this advance in the context of biomolecule-driven enrichment methods.

Effect of chronic oil pollution on salt-marsh nitrogen fixation (acetylene redution). [Spartina alterniflora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomson, A.D.; Webb, K.L.

1984-03-01

Annual acetylene reduction rates associated with intertidal communities in a chronically oil polluted Virgina salt marsh were compared to rates measured in an undisturbed marsh. Chronic oil treatment resulted in visible damage to the higher plants of the Spartina alterniflora zones; however, vegetation-associated acetylene reduction was not different from the untreated control. Sediment rates generally were affected little by oil application, except during the summer when rates in the median tidal elevation zones were considerably higher than those of the control. Acetylene reduction occurred in all transects, each of which extended from upper mudflat to the Spartina patens zone. Intertidalmore » sediment acetylene reduction was patchy, both spatially and seasonally. Estimated rates were greatest near the surface; free-living bacterial N/sub 2/ fixation activity averaged 2.23 mg N per m/sup 2/ per d (range = undetectable to 365 mg N per m/sup 2/ per d) in the untreated and 3.17 mg N per m/sup 2/ per d (range = undetectable to 564 mg N per m/sup 2/ per d) in the oil-treated marsh during the year. Vegetation-associated N/sub 2/ fixation activity yielded highest overall mean rates (156 mg N per M/sub 2/ per d). The seasonal pattern of sediment and vegetation-associated fixation may be controlled by temperature and availability of oxidizable substrates. 39 references, 2 figures, 5 tables.« less

Nitrogen Fixation (Acetylene Reduction) by Epiphytes of Freshwater Macrophytes

PubMed Central

Finke, Linda R.; Seeley, H. W.

1978-01-01

The involvement of epiphytic microorganisms in nitrogen fixation was investigated in a shallow freshwater pond near Ithaca, N.Y. The acetylene reduction technique was used to follow diel and seasonal cycles of nitrogen fixation by epiphytes of Myriophyllum spicatum. Acetylene-reducing activity was maximal between noon and 6 p.m., but substantial levels of activity relative to daytime rates continued through the night. Experiments with the seasonal course of activity showed a gradual decline during the autumn months and no activity in January or February. Activity commenced in May, with an abrupt increase to levels between 0.45 and 0.95 nmol of ethylene formed per mg (dry weight) of plant per h. Through most of the summer months, mean rates of acetylene reduction remained between 0.15 and 0.60 nmol/mg (dry weight) per h. It was calculated from diel and seasonal cycles that, in the pond areas studied, epiphytes were capable of adding from 7.5 to 12.5 μg of N per mg of plant per year to the pond. This amount is significant relative to the total amount of nitrogen incorporated into the plant. Blue-green algae (cyanobacteria), particularly Gloeotrichia, appeared to bear prime responsibility for nitrogen fixation, but photosynthetic bacteria of the genus Rhodopseudomonas were isolated from M. spicatum and shown to support high rates of acetylene reduction. PMID:16345301

Fluoroester Co-Solvents for Low-Temperature Li+ Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall; Bugga, Ratnakumar; Prakash, G. K. Surya; Smith, Kiah; Bhalla, Pooja

2009-01-01

Electrolytes comprising LiPF6 dissolved in alkyl carbonate/fluoroester mixtures have been found to afford improved low-temperature performance and greater high-temperature resilience in rechargeable lithium-ion electrochemical cells. These and other electrolytes comprising lithium salts dissolved mixtures of esters have been studied in continuing research directed toward extending the lower limit of operating temperatures of such cells. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles. The purpose of the present focus on high-temperature resilience in addition to low-temperature performance is to address issues posed by the flammability of the esters and, at temperatures near the upper end (about 55 C) of their intended operating temperature range, by their high chemical reactivity. As used here, high-temperature resilience signifies, loosely, a desired combination of low flammability of an electrolyte mixture and the ability of a cell that contains the mixture to sustain a relatively small loss of reversible charge/discharge capacity during storage in the fully charged condition at high temperature. The selection of fluoroesters for study as candidate electrolyte solvent components to increase high-temperature resilience was prompted in part by the observation that like other halogenated compounds, fluoroesters have low flammability. The fluoroesters investigated in this study include trifluoroethyl butyrate (TFEB), ethyl trifluoroacetate (ETFA), trifluoroethyl acetate (TFEA), and methyl pentafluoropropionate (MPFP). Solvent mixtures were prepared by mixing these fluoroesters with two other esters: ethylene carbonate (EC) and ethyl methyl carbonate (EMC).

Experimental investigations on a diesel engine operated with fuel blends derived from a mixture of Pakistani waste tyre oil and waste soybean oil biodiesel.

PubMed

Qasim, Muhammad; Ansari, Tariq Mahmood; Hussain, Mazhar

2017-10-18

The waste tyre and waste cooking oils have a great potential to be used as alternative fuels for diesel engines. The aim of this study was to convert light fractions of pyrolysis oil derived from Pakistani waste vehicle tyres and waste soybean oil methyl esters into valuable fuel and to reduce waste disposal-associated environmental problems. In this study, the waste tyre pyrolysis liquid (light fraction) was collected from commercial tyre pyrolysis plant and biodiesel was prepared from waste soybean oil. The fuel blends (FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50) were prepared from a 30:70 mixture of waste tyre pyrolysis liquid and waste soybean oil methyl esters with different proportions of mineral diesel. The mixture was named as the fuel mixture of waste oils (FMWO). FT-IR analysis of the fuel mixture was carried out using ALPHA FT-IR spectrometer. Experimental investigations on a diesel engine were carried out with various FMWO blends. It was observed that the engine fuel consumption was marginally increased and brake thermal efficiency was marginally decreased with FMWO fuel blends. FMWO10 has shown lowest NOx emissions among all the fuel blends tested. In addition, HC, CO and smoke emissions were noticeably decreased by 3.1-15.6%, 16.5-33.2%, and 1.8-4.5%, respectively, in comparison to diesel fuel, thereby qualifying the blends to be used as alternative fuel for diesel engines.

NIOSH Manual of Analytical Methods (third edition). Fourth supplement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-15

The NIOSH Manual of Analytical Methods, 3rd edition, was updated for the following chemicals: allyl-glycidyl-ether, 2-aminopyridine, aspartame, bromine, chlorine, n-butylamine, n-butyl-glycidyl-ether, carbon-dioxide, carbon-monoxide, chlorinated-camphene, chloroacetaldehyde, p-chlorophenol, crotonaldehyde, 1,1-dimethylhydrazine, dinitro-o-cresol, ethyl-acetate, ethyl-formate, ethylenimine, sodium-fluoride, hydrogen-fluoride, cryolite, sodium-hexafluoroaluminate, formic-acid, hexachlorobutadiene, hydrogen-cyanide, hydrogen-sulfide, isopropyl-acetate, isopropyl-ether, isopropyl-glycidyl-ether, lead, lead-oxide, maleic-anhydride, methyl-acetate, methyl-acrylate, methyl-tert-butyl ether, methyl-cellosolve-acetate, methylcyclohexanol, 4,4'-methylenedianiline, monomethylaniline, monomethylhydrazine, nitric-oxide, p-nitroaniline, phenyl-ether, phenyl-ether-biphenyl mixture, phenyl-glycidyl-ether, phenylhydrazine, phosphine, ronnel, sulfuryl-fluoride, talc, tributyl-phosphate, 1,1,2-trichloro-1,2,2-trifluoroethane, trimellitic-anhydride, triorthocresyl-phosphate, triphenyl-phosphate, and vinyl-acetate.

DNA methylation analysis from saliva samples for epidemiological studies.

PubMed

Nishitani, Shota; Parets, Sasha E; Haas, Brian W; Smith, Alicia K

2018-06-18

Saliva is a non-invasive, easily accessible tissue, which is regularly collected in large epidemiological studies to examine genetic questions. Recently, it is becoming more common to use saliva to assess DNA methylation. However, DNA extracted from saliva is a mixture of both bacterial and human DNA derived from epithelial and immune cells in the mouth. Thus, there are unique challenges to using salivary DNA in methylation studies that can influence data quality. This study assesses: (1) quantification of human DNA after extraction; (2) delineation of human and bacterial DNA; (3) bisulfite conversion (BSC); (4) quantification of BSC DNA; (5) PCR amplification of BSC DNA from saliva and; (6) quantitation of DNA methylation with a targeted assay. The framework proposed will allow saliva samples to be more widely used in targeted epigenetic studies.

Molecular Modulation of Inhibitors of Apoptosis as a Novel Approach for Radiosensitization of Human Prostate Cancer

DTIC Science & Technology

2008-11-01

was purified from natural racemic gossypol. Briefly, racemic gossypol was reacted with L - phenylalanine methyl ester hydrochloride overnight at room...solution of the resolved (F)-gossypol- phenylalanine methyl ester Schiff’s base was hydrolyzed by a mixture of tetrahydro- furan, glacial acetic acid...suppression of NF-kappaB-regulated antiapoptotic and metastatic gene products. Mol Pharmacol 2007; 71: 209-19. [136]Wang L , Du F, Wang X. TNF- alpha induces

A Practical Methylation Procedure for (1H)-1,2,4-Triazole (Preprint)

DTIC Science & Technology

2007-06-01

on alkylations with higher molecular weight electrophiles, rather than on synthesizing the methyl homologue, the simple reaction to obtain the...an equivalent of the 25% w/w methanolic sodium methoxide solution with heating to 65 °C for 5 minutes in a 5 mL sealed microwave reaction vessel ...requisite neat iodomethane, and recrimping the 5 mL reaction vessel , the reaction vessel was reinserted into the microwave apparatus . The reaction mixture

Fabrication of metallized nanoporous films from the self-assembly of a block copolymer and homopolymer mixture.

PubMed

Li, Xue; Zhao, Shuying; Zhang, Shuxiang; Kim, Dong Ha; Knoll, Wolfgang

2007-06-19

Inorganic compound HAuCl4, which can form a complex with pyridine, is introduced into a poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) block copolymer/poly(methyl methacrylate) (PMMA) homopolymer mixture. The orientation of the cylindrical microdomains formed by the P2VP block, PMMA, and HAuCl4 normal to the substrate surface can be generated via cooperative self-assembly of the mixture. Selective removal of the homopolymer can lead to porous nanostructures containing metal components in P2VP domains, which have a novel photoluminescence property.

Quercetin and fisetin enhanced the small intestine cellular uptake and plasma levels of epi-catechins in in vitro and in vivo models.

PubMed

Chung, Jin-Oh; Lee, Seon-Bong; Jeong, Kang-Hyun; Song, Ji-Hoon; Kim, Su-Kyung; Joo, Kyung-Mi; Jeong, Hyun-Woo; Choi, Jin-Kyu; Kim, Jeong-Kee; Kim, Wan-Gi; Shin, Song-Seok; Shim, Soon-Mi

2018-01-24

Quercetin and fisetin, known as catechol-containing flavonoids, could positively affect the absorption of catechins due to their strong affinity for catechol-O-methyl transferase (COMT), which can methylate and cause the excretion of catechins. The current study examined the effect of quercetin and fisetin on the absorption of epi-catechins (ECs) by using a Caco-2 cell line and an in vivo model. The intestinal transport of total catechins by Caco-2 cells was enhanced from 1.3- to 1.6-fold and 1.4- to 1.7-fold by adding quercetin and fisetin, respectively, compared to the control. It was even higher in the treatment with a mixture of quercetin and fisetin. While EC had the highest value of intestinal transport (169% of the control) in 10% quercetin treatment, EGC (235%), EGCG (244%), and ECG (242%) were significantly transported in the treatment with a 5% mixture of quercetin and fisetin (p < 0.05). In an in vivo pharmacokinetic study, the values of the area under the plasma concentration-time curve (AUC, ng h mL -1 ) were also higher in rats orally administered EGCG with 10% quercetin (365.5 ± 25.5) or 10% fisetin (825.3 ± 46.7) than in those administered EGCG only (111.3 ± 13.1). Methylated quercetin and methylated fisetin were determined to be m/z 317.24 and m/z 301.25 [M + H] + with their own product ions, respectively. The results indicate that quercetin or fisetin is superior to ECs for methylation by COMT.

Aviator’s Breathing Oxygen Specifications

DTIC Science & Technology

1976-12-01

Sheinson (2]), it can cocrystallize with acetylene. While solid acetylene will float on LOX, cocrystals with over 50% nitrous oxide can form a suspension...in LOX, and cocrystals wi’h over 70% nitrous oxide will sink and can detonate. Thus the simultatieous presence of icetylene and nitrous oxide above

77 FR 13969 - Revising Standards Referenced in the Acetylene Standard

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

.... OSHA-2011-0183] RIN 1218-AC64 Revising Standards Referenced in the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Department of Labor. ACTION: Final rule; confirmation of effective date. SUMMARY: OSHA is confirming the effective date of its direct final rule that revises the...

Methane emissions measured at two California landfills by OTM-10 and an acetylene tracer method

EPA Science Inventory

Methane emissions were measured at two municipal solid waste landfills in California using static flux chambers, an optical remote sensing approach known as vertical radial plume mapping (VRPM) using a tunable diode laser (TDL) and a novel acetylene tracer method. The tracer meth...

TOXICITY OF ACETYLENIC ALCOHOLS TO THE FATHEAD MINNOW, PIMEPHALES PROMELAS: NARCOSIS AND PROELECTROPHILE ACTIVATION

EPA Science Inventory

The 96-h LC50 values for 16 acetylenic alcohols in the fathead minnow (Pimephales promelas) were determined using continuous-flow diluters. The measured LC50 values for seven tertiary propargylic alcohols agreed closely with the QSAR predictions based upon data for other organic ...

Cu-catalyzed aerobic oxidative cyclizations of 3-N-hydroxyamino-1,2-propadienes with alcohols, thiols, and amines to form α-O-, S-, and N-substituted 4-methylquinoline derivatives.

PubMed

Sharma, Pankaj; Liu, Rai-Shung

2015-03-16

A one-pot, two-step synthesis of α-O-, S-, and N-substituted 4-methylquinoline derivatives through Cu-catalyzed aerobic oxidations of N-hydroxyaminoallenes with alcohols, thiols, and amines is described. This reaction sequence involves an initial oxidation of N-hydroxyaminoallenes with NuH (Nu = OH, OR, NHR, and SR) to form 3-substituted 2-en-1-ones, followed by Brønsted acid catalyzed intramolecular cyclizations of the resulting products. Our mechanistic analysis suggests that the reactions proceed through a radical-type mechanism rather than a typical nitrone-intermediate route. The utility of this new Cu-catalyzed reaction is shown by its applicability to the synthesis of several 2-amino-4-methylquinoline derivatives, which are known to be key precursors to several bioactive molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adsorption of methyl orange by synthesized and functionalized-CNTs with 3-aminopropyltriethoxysilane loaded TiO2 nanocomposites.

PubMed

Ahmad, Amirah; Razali, Mohd Hasmizam; Mamat, Mazidah; Mehamod, Faizatul Shimal Binti; Anuar Mat Amin, Khairul

2017-02-01

This study aims to develop a highly efficient adsorbent material. CNTs are prepared using a chemical vapor deposition method with acetylene and synthesized mesoporous Ni-MCM41 as the carbon source and catalyst, respectively, and are then functionalized using 3-aminopropyltriethoxysilane (APTES) through the co-condensation method and loaded with commercial TiO 2 . Results of X-ray powder diffraction (XRD), Raman spectra, and Fourier transform infrared spectroscopy (FTIR) confirm that the synthesized CNTs grown are multi-walled carbon nanotubes (MWNTs). Transmission electron microscopy shows good dispersion of TiO 2 nanoparticles onto functionalized-CNTs loaded TiO 2 , with the diameter of a hair-like structure measuring between 3 and 8 nm. The functionalized-CNTs loaded TiO 2 are tested as an adsorbent for removal of methyl orange (MO) in aqueous solution, and results show that 94% of MO is removed after 10 min of reaction, and 100% after 30 min. The adsorption kinetic model of functionalized-CNTs loaded TiO 2 follows a pseudo-second order with a maximum adsorption capacity of 42.85 mg/g. This study shows that functionalized-CNTs loaded TiO 2 has considerable potential as an adsorbent material due to the short adsorption time required to achieve equilibrium. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sorption characteristic of coal as regards of gas mixtures emitted in the process of the self-heating of coal

NASA Astrophysics Data System (ADS)

Wojtacha-Rychter, Karolina; Smoliński, Adam

2017-10-01

One of the most challenging tasks in the coal mining sector is the detection of endogenous fire risks. Under field conditions, the distance between the points where samples for the analyses are collected and the actual place where coal self-heating takes place may be quite remote. Coal is a natural sorbent with a diverse character of pore structures which are surrounded by fractures and cleavage planes constituting ideal spaces for the flow and adsorption of gases. The gases (methane, ethane, ethylene, propane, propylene, acetylene, carbon dioxide, carbon monoxide, hydrogen) released from the source of fire migrate through the seam and may be subject to adsorption, or they may cause the desorption of gases accumulated in coal. Therefore, the values of reference sample concentrations may be overstated or understated, respectively. The objective of this experimental study was to investigate the adsorption phenomena accompanying the flow of a multi-component gas mixture through a coal bed which may occur in situ. The research was conducted by means of a method based on a series of calorimetric/chromatographic measurements taken to determine the amount of gases released during coal heating at various temperatures under laboratory conditions. Based on the results obtained in the course of the experiments, it was concluded that the amount of gas adsorbed in the seam depends on the type of coal and the gas. Within the multi-component gas mixture, hydrocarbons demonstrated the largest sorption capacity, especially as concerns propylene.

Thermal insulation for high temperature microwave sintering operations and method thereof

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.; Morrow, Marvin S.

1995-01-01

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering.

Method of preparing thermal insulation for high temperature microwave sintering operations

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.; Morrow, Marvin S.

1996-01-01

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering.

Toward power scaling in an acetylene mid-infrared hollow-core optical fiber gas laser: effects of pressure, fiber length, and pump power

NASA Astrophysics Data System (ADS)

Weerasinghe, H. W. Kushan; Dadashzadeh, Neda; Thirugnanasambandam, Manasadevi P.; Debord, Benoît.; Chafer, Matthieu; Gérôme, Frédéric; Benabid, Fetah; Corwin, Kristan L.; Washburn, Brian R.

2018-02-01

The effect of gas pressure, fiber length, and optical pump power on an acetylene mid-infrared hollow-core optical fiber gas laser (HOFGLAS) is experimentally determined in order to scale the laser to higher powers. The absorbed optical power and threshold power are measured for different pressures providing an optimum pressure for a given fiber length. We observe a linear dependence of both absorbed pump energy and lasing threshold for the acetylene HOFGLAS, while maintaining a good mode quality with an M-squared of 1.15. The threshold and mode behavior are encouraging for scaling to higher pressures and pump powers.

Furfural from Pine Needle Extract Inhibits the Growth of a Plant Pathogenic Fungus, Alternaria mali

PubMed Central

Yoo, Sun Kyun; Moon, Sung-Kwon; Lee, Ung-Soo

2007-01-01

The antifungal effect of pine needle extract prepared by a distinguishable extraction method and the dry distillation method, was examined. The effect of this extract itself was insignificant. The chemical components of pine needle extract were then investigated by gas chromatographic analysis, and four chemical components, acetol, furfural, 5-methyl furfural, and terpine-4-ol, were identified. The antifungal effects of those four chemical components against Alternaria mali (A. mali), an agent of Alternaria blotch of apple, were then examined. It was observed that the minimum inhibitory concentrations (MICs) were 6.25, 0.78, 0.78, and 12.5 (mg/ml) of acetol, furfural, 5-methyl furfural, and terpine-4-ol, respectively. MICs of furfural and 5-methyl furfural had the same order of magnitude as that of an antifungal agrochemical, chlorothalonil. Although furfural itself can not be completely substituted for an antifungal agrochemical, a partial mixture of furfural and antifungal agrochemical may be used as a substitute. The use of agrochemicals for the prevention of plant disease caused by pathogenic fungus such as A. mali could be partially reduced by the application of this mixture. PMID:24015067

Flexural properties of ethyl or methyl methacrylate-UDMA blend polymers.

PubMed

Kanie, Takahito; Kadokawa, Akihiko; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

2010-10-01

Light-curing polyethyl methacrylate (PEMA)-urethane dimethacrylate (UDMA) resins and polymethyl methacrylate (PMMA)-UDMA resins were prepared by two processes. For first step, PEMA or PMMA powders were fully dissolved in ethyl methacrylate (EMA) or methyl methacrylate (MMA) and then the PEMA-EMA/PMMA-MMA mixtures were mixed with UDMA. The flexural properties of cured PEMA-UDMA and PMMA-UDMA polymers were measured using two PEMA (Mw: 300,000-400,000 and 650,000-1,000,000) and three PMMA (Mw: 30,000-60,000, 350,000 and 650,000-1,000,000) powders with different molecular weight, four mixing ratios of PMMA-MMA, and three mixing ratios of PMMA-MMA mixture and UDMA oligomer. Polymers with PMMA(Mw: 350,000) MMA=25/50, and with PMMA(Mw: 350,000)-MMA/UDMA=1/2 and =1/1, showed no-fracture in a flexural test at 1 mm/min and flexural strength and flexural modulus showed no significant difference compared with those of commercially available heat- and self-curing acrylic resins (p>0.01). Within limitation of this investigation, methyl methacrylate-UDMA blend polymer of this composition is available for denture base resin.

Hydration of Acetylene: A 125th Anniversary

ERIC Educational Resources Information Center

Ponomarev, Dmitry A.; Shevchenko, Sergey M.

2007-01-01

The year 2006 is the 125th anniversary of a chemical reaction, the discovery of which by Mikhail Kucherov had a profound effect on the development of industrial chemistry in the 19-20th centuries. This was the hydration of alkynes catalyzed by mercury ions that made possible industrial production of acetaldehyde from acetylene. Historical…

Alkyl substituent effects on gas-phase acidities - The influence of hybridization.

NASA Technical Reports Server (NTRS)

Brauman, J. I.; Blair, L. K.

1971-01-01

Exploration of the effect on acidity of alkyl groups bonded to trigonal and digonal carbon. Some results on the relative acidities of toluene and p-xylene, and acetylene and substitute acetylenes, as determined by ion cyclotron resonance (icr) spectroscopy, are described. Some limitations of the CNDO/2 calculation method are discussed.

The Formation of Ethane from Carbon Dioxide under Cold Plasma

NASA Astrophysics Data System (ADS)

Zhang, Xiu-ling; Zhang, Lin; Dai, Bin; Gong, Wei-min; Liu, Chang-hou

2001-04-01

Pulsed-corona plasma has been used as a new method for ethane dehydrogenation at low temperature and normal pressure using carbon dioxide as an oxidant in this paper. The effect of carbon dioxide content in the feed, power input, and flow rate of the reactants on the ethane dehydrogenation has been investigated. The experimental results show that the conversion of ethane increases with the increase in the amount of carbon dioxide in the feed. The yield of ethylene and acetylene decreases with the increase in the yield of carbon monoxide, indicating that the increased carbon dioxide leads to the part of ethylene and acetylene being oxidized to carbon monoxide. Power input is primarily an electrical parameter in pulsed-corona plasma, which plays an important role in reactant conversion and product formation. When the power input reaches 16 W, ethane conversion is 41.0% and carbon dioxide conversion is 26.3%. The total yield of ethylene and acetylene is 15.6%. The reduced flow rate of feed improves the conversion of ethane, carbon dioxide and the yield of acetylene, and induces carbon deposit as well.

Is the tungsten(IV) complex (NEt4)2[WO(mnt)2] a functional analogue of acetylene hydratase?

PubMed Central

Schreyer, Matthias

2017-01-01

The tungsten(IV) complex (Et4N)2[W(O)(mnt)2] (1; mnt = maleonitriledithiolate) was proposed (Sarkar et al., J. Am. Chem. Soc. 1997, 119, 4315) to be a functional analogue of the active center of the enzyme acetylene hydratase from Pelobacter acetylenicus, which hydrates acetylene (ethyne; 2) to acetaldehyde (ethanal; 3). In the absence of a satisfactory mechanistic proposal for the hydration reaction, we considered the possibility of a metal–vinylidene type activation mode, as it is well established for ruthenium-based alkyne hydration catalysts with anti-Markovnikov regioselectivity. To validate the hypothesis, the regioselectivity of tungsten-catalyzed alkyne hydration of a terminal, higher alkyne had to be determined. However, complex 1 was not a competent catalyst for the hydration of 1-octyne under the conditions tested. Furthermore, we could not observe the earlier reported hydration activity of complex 1 towards acetylene. A critical assessment of, and a possible explanation for the earlier reported results are offered. The title question is answered with "no". PMID:29181113

A Stable Fluorinated and Alkylated Lithium Malonatoborate Salt for Lithium Ion Battery Application

DOE PAGES

Wan, Shun; Jiang, Xueguang; Guo, Bingkun; ...

2015-04-27

A new fluorinated and alkylated lithium malonatoborate salt, lithium bis(2-methyl-2-fluoromalonato)borate (LiBMFMB), has been synthesized for lithium ion battery application. A 0.8 M LiBMFMB solution is obtained in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1:2 by wt.). The new LiBMFMB based electrolyte exhibits good cycling stability and rate capability in LiNi0.5Mn1.5O4 and graphite based half-cells.

A Puzzling Alcohol Dehydration Reaction Solved by GC-MS Analysis

NASA Astrophysics Data System (ADS)

Pelter, Michael W.; Macudzinski, Rebecca M.

1999-06-01

We have adapted the dehydration of 2-methyl-2-propanol to a "puzzle" approach for use in our second-semester chemistry major organic laboratory. The reaction of 2-methyl-2-propanol with ~50% sulfuric acid at 100 °C yields isobutylene, which reacts further by a "puzzling" reaction. By coupling the GC/MS analysis of the product mixture with their knowledge of the mechanism of alcohol dehydration and alkene reactivity, students are able to identify the major products of this reaction.

High temperature concrete composites containing organosiloxane crosslinked copolymers

DOEpatents

Zeldin, Arkady; Carciello, Neal; Kukacka, Lawrence; Fontana, Jack

1980-01-01

This invention relates to high temperature polymer concrete composites comprising about 10-30% by weight of a liquid monomer mixture consisting essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures theroef; and about 70-90% by weight of an inert inorganic filler system containing silica sand and preferably a member selected from the group consisting of portland cement, Fe.sub.2 O.sub.3, carbon black and mixtures thereof; and optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

Electro-Optically Active Monomers: Synthesis and Characterization of Thin Films of Liquid Crystalline Substituted Polyacetylenes

NASA Technical Reports Server (NTRS)

Duran, R. S.

1995-01-01

The overall objective of this study was the description of the behavior of mesogen substituted acetylene monomers and polymers in monolayer films at the air/water interface and as multilayer films including the formation of such films. Fundamental knowledge to be gained would include the effect of balancing hydrophilic and hydrophobic tendencies in a molecule more complex than the classical fatty acids or lipids. The effect of molecular shape on the packing and thus the ultimate stability of monolayers formed from these new molecules was explored. The work takes on the challenge of preorienting monomers in well-ordered arrays prior to attempting polymerization with the hope that order would be preserved in any resulting polymer. New knowledge gained with regard to the acetylenic monomers includes processing of the acetylene monomer into multi-layer films, followed by the design and synthesis of a second generation of improved monomer structure for superior LBK film transfer properties. A third generation of acetylenic monomer was synthesized which approaches more closely the goal of solid state polymerization of these materials. A parallel study took a different approach. The materials are pre-formed poly(phenylene-acetylene) polymers so questions about reactivity are mute. The materials are a variation on the well-known hairy-rod polymers with regard to their Langmuir film-forming properties. Overall, the goal was to demonstrate that these polymers could be processed into NLO materials with novel polar order.

Structure, Stabilities, Thermodynamic Properties, and IR Spectra of Acetylene Clusters (C2H2)n=2-5.

PubMed

Karthikeyan, S; Lee, Han Myoung; Kim, Kwang S

2010-10-12

There are no clear conclusions over the structures of the acetylene clusters. In this regard, we have carried out high-level calculations for acetylene clusters (C2H2)2-5 using dispersion-corrected density functional theory (DFT-D), Møller-Plesset second-order perturbation theory (MP2); and coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)] at the complete basis set limit. The lowest energy structure of the acetylene dimer has a T-shaped structure of C2v symmetry, but it is nearly isoenergetic to the displaced stacked structure of C2h symmetry. We find that the structure shows the quantum statistical distribution for configurations between the T-shaped and displaced stacked structures for which the average angle (|θ̃|) between two acetylene molecules would be 53-78°, close to the T-shaped structure. The trimer has a triangular structure of C3h symmetry. The tetramer has two lowest energy isomers of S4 and C2h symmetry in zero-point energy (ZPE)-uncorrected energy (ΔEe), but one lowest energy isomer of C2v symmetry in ZPE-corrected energy (ΔE0). For the pentamer, the global minimum structure is C1 symmetry with eight sets of T-type π-H interactions and a set of π-π interactions. Our high-level ab initio calculations are consistent with available experimental data.

Indole synthesis by conjugate addition of anilines to activated acetylenes and an unusual ligand-free copper(II)-mediated intramolecular cross-coupling.

PubMed

Gao, Detian; Back, Thomas G

2012-11-12

A versatile new synthesis of indoles was achieved by the conjugate addition of N-formyl-2-haloanilines to acetylenic sulfones, ketones, and esters followed by a copper-catalyzed intramolecular C-arylation. The conjugate addition step was conducted under exceptionally mild conditions at room temperature in basic, aqueous DMF. Surprisingly, the C-arylation was performed most effectively by employing copper(II) acetate as the catalyst in the absence of external ligands, without the need for protection from air or water. An unusual feature of this process, for the case of acetylenic ketones, is the ability of the initial conjugate-addition product to serve as a ligand for the catalyst, which enables it to participate in the catalysis of its further transformation to the final indole product. Mechanistic studies, including EPR experiments, indicated that copper(II) is reduced to the active copper(I) species by the formate ion that is produced by the base-catalyzed hydrolysis of DMF. This process also served to recycle any copper(II) that was produced by the adventitious oxidation of copper(I), thereby preventing deactivation of the catalyst. Several examples of reactions involving acetylenic sulfones attached to a modified Merrifield resin demonstrated the feasibility of solid-phase synthesis of indoles by using this protocol, and tricyclic products were obtained in one pot by employing acetylenic sulfones that contain chloroalkyl substituents. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acute aquatic toxicity of biodiesel fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, B.; Haws, R.; Little, D.

1995-12-31

This study develops data on the acute aquatic toxicity of selected biodiesel fuels which may become subject to environmental effects test regulations under the US Toxic Substances Control Act (TSCA). The test substances are Rape Methyl Ester (RME), Rape Ethyl Ester (REE), Methyl Soyate (MS), a biodiesel mixture of 20% REE and 80% Diesel, a biodiesel mixture of 50% REE and diesel, and a reference substance of Phillips D-2 Reference Diesel. The test procedure follows the Daphnid Acute Toxicity Test outlined in 40 CFR {section} 797.1300 of the TSCA regulations. Daphnia Magna are exposed to the test substance in amore » flow-through system consisting of a mixing chamber, a proportional diluter, and duplicate test chambers. Novel system modifications are described that accommodate the testing of oil-based test substances with Daphnia. The acute aquatic toxicity is estimated by an EC50, an effective concentration producing immobility in 50% of the test specimen.« less

Organic History and Ice-Rock Decoupling on Enceladus

NASA Astrophysics Data System (ADS)

Zolotov, M. Y.

2007-12-01

The Cassini detection of methane, propane and acetylene in the Enceladus plume, and condensed organic compounds (OC) on the south polar region imply an organic-bearing interior of the moon. At least a few wt. % of C is expected in rocks from which Enceladus accreted. By analogy with carbonaceous chondrites, the majority of accreted OC was in a polymer in which polyaromatic groups are linked by O-, N-, and S-bearing aliphatic units. If accreted, cometary-type materials also delivered CO2, CO(?), methanol, ethane, ethene, acetylene, and condensed OC. Subsequent water ice melting and hydrothermal processes driven by decay of short-lived radionuclides led to dissolution of CO, CO2 and methanol in water and transformations of the polymer and cometary OC. CO converted to formic acid, carbonate species, methanol and methane. Hydrous pyrolysis and oxidation of the polymer partially liberated aromatic molecules and led to the formation of O-bearing OC (carboxylic and amino acids, alcohols). Increase in temperature favored oxidation of OC to carbonate species and N2, and led to graphitization of the polymer. Despite net oxidation of OC driven by H2 escape, mineral- catalyzed Fisher-Tropsch like synthesis of hydrocarbons and methane occurred in H2-rich niches. As a result, an array of aromatic, aliphatic, and N-, O-, S-bearing OC, and methane was delivered into a primordial water ocean in hydrothermal fluids. Highly soluble OC (acids, alcohols) made multiple passes through hydrothermal systems causing further oxidation of OC in rocks and solutions. In contrast, hydrocarbons exolved from cold oceanic water and formed an organic layer below the ice shell. Subsequent cooling of ocean-entering fluids and ocean freezing from above led to further separation and accumulation of OC. Some OC was trapped in ice, and methane formed clathrates. After freezing of salt eutectic brines, the light oil (a solution/mixture of ethane, propane, butane, ethene, acetylene, methanol, toluene etc.) remained unfrozen and decoupled the ice shell from underlying salt deposits and rocks. Even after oil solidification, if it occurred, the organic layer had a lower viscosity than salts and ice. An uneven pressure and/or topography at the ice-salt boundary could have led to preferential oil (and salt?) accumulation below the south polar region. Throughout history (and today), the uneven oil-rich layer could have favored tidal motions and heat generation at the bottom of the ice shell.

DNA methylation analysis reveals distinct methylation signatures in pediatric germ cell tumors.

PubMed

Amatruda, James F; Ross, Julie A; Christensen, Brock; Fustino, Nicholas J; Chen, Kenneth S; Hooten, Anthony J; Nelson, Heather; Kuriger, Jacquelyn K; Rakheja, Dinesh; Frazier, A Lindsay; Poynter, Jenny N

2013-06-27

Aberrant DNA methylation is a prominent feature of many cancers, and may be especially relevant in germ cell tumors (GCTs) due to the extensive epigenetic reprogramming that occurs in the germ line during normal development. We used the Illumina GoldenGate Cancer Methylation Panel to compare DNA methylation in the three main histologic subtypes of pediatric GCTs (germinoma, teratoma and yolk sac tumor (YST); N = 51) and used recursively partitioned mixture models (RPMM) to test associations between methylation pattern and tumor and demographic characteristics. We identified genes and pathways that were differentially methylated using generalized linear models and Ingenuity Pathway Analysis. We also measured global DNA methylation at LINE1 elements and evaluated methylation at selected imprinted loci using pyrosequencing. Methylation patterns differed by tumor histology, with 18/19 YSTs forming a distinct methylation class. Four pathways showed significant enrichment for YSTs, including a human embryonic stem cell pluripotency pathway. We identified 190 CpG loci with significant methylation differences in mature and immature teratomas (q < 0.05), including a number of CpGs in stem cell and pluripotency-related pathways. Both YST and germinoma showed significantly lower methylation at LINE1 elements compared with normal adjacent tissue while there was no difference between teratoma (mature and immature) and normal tissue. DNA methylation at imprinted loci differed significantly by tumor histology and location. Understanding methylation patterns may identify the developmental stage at which the GCT arose and the at-risk period when environmental exposures could be most harmful. Further, identification of relevant genetic pathways could lead to the development of new targets for therapy.

In vitro activation of ammonia monooxygenase from Nitrosomonas europaea by copper.

PubMed Central

Ensign, S A; Hyman, M R; Arp, D J

1993-01-01

The effect of copper on the in vivo and in vitro activity of ammonia monooxygenase (AMO) from the nitrifying bacterium Nitrosomonas europaea was investigated. The addition of CuCl2 to cell extracts resulted in 5- to 15-fold stimulation of ammonia-dependent O2 consumption, ammonia-dependent nitrite production, and hydrazine-dependent ethane oxidation. AMO activity was further stimulated in vitro by the presence of stabilizing agents, including serum albumins, spermine, or MgCl2. In contrast, the addition of CuCl2 and stabilizing agents to whole-cell suspensions did not result in any stimulation of AMO activity. The use of the AMO-specific suicide substrate acetylene revealed two populations of AMO in cell extracts. The low, copper-independent (residual) AMO activity was completely inactivated by acetylene in the absence of exogenously added copper. In contrast, the copper-dependent (activable) AMO activity was protected against acetylene inactivation in the absence of copper. However, in the presence of copper both populations of AMO were inactivated by acetylene. [14C]acetylene labelling of the 27-kDa polypeptide of AMO revealed the same extent of label incorporation in both whole cells and optimally copper-stimulated cell extracts. In the absence of copper, the label incorporation in cell extracts was proportional to the level of residual AMO activity. Other metal ions tested, including Zn2+, Co2+, Ni2+, Fe2+, Fe3+, Ca2+, Mg2+, Mn2+, Cr3+, and Ag+, were ineffective at stimulating AMO activity or facilitating the incorporation of 14C label from [14C]acetylene into the 27-kDa polypeptide. On the basis of these results, we propose that loss of AMO activity upon lysis of N. europaea results from the loss of copper from AMO, generating a catalytically inactive, yet stable and activable, form of the enzyme. Images PMID:8458839

A DFT study and micro-kinetic analysis of acetylene selective hydrogenation on Pd-doped Cu(111) surfaces

NASA Astrophysics Data System (ADS)

Ma, Ling-Ling; Lv, Cun-Qin; Wang, Gui-Chang

2017-07-01

Semi-hydrogenation of acetylene in a hydrogen-rich stream is an industrially important process. Inspired by the recent experiments that Cu(111) surface doped by a small number of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H2 molecule as well as the high selective hydrogenation of acetylene as compared with pure Cu and Pd metal alone at low-temperature, here we performed systematic first-principles calculations to investigate the corresponding reaction mechanism related to the acetylene hydrogenation processes on single atom alloys (SAAs) and monolayer Pd/Cu(111) (i.e.,1.00 ML Pd/Cu(111)) model catalysts in detail, and to explore the possible factors controlling the high selectivity on SAAs. Our results clearly demonstrate that the SAA catalyst has higher selectivity for the ethylene formation than that of 1.00 ML Pd/Cu(111), and lower activity for the acetylene conversion compared with that of 1.00 ML Pd/Cu(111). The relatively high selectivity on SAA is mainly due to the facile desorption of ethylene and moderate activity in the dissociation of molecular H2. The main factor which lowers the selectivity towards the ethylene formation on 1.00 ML Pd/Cu(111) is that this system has a higher capacity to promote the breaking of Csbnd H/Csbnd C bonds, which leads to the formation of carbonaceous deposits and polymers such as benzene, and thus reduces the selectivity for the ethylene formation. Meanwhile, it was found that the desorption energy of ethylene on these two surfaces was smaller than the energy barrier of further hydrogenation, which results in the absence of ethane on these two systems. Micro-kinetic model analysis provides a further valuable insight into the evidence for the key factors controlling the catalytic activity and selectivity towards the selective hydrogenation of acetylene. Our findings may help people to design a highly selective hydrogenation catalyst by controlling the balance between the H2 dissociation and Csbnd H/Csbnd C bond broken processes, and a good catalyst should be the one with the modest catalytic activity in the activation of molecular H2. At the same time, the present work provides an extremely significant mechanism of acetylene trimerization to form benzene and carbon formation.

Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall; Bugga, Ratnakumar; Surampudi, Subbarao

2003-01-01

Electrolytes comprising LiPF6 dissolved at a concentration of 1.0 M in three different mixtures of alkyl carbonates have been found well suited for use in rechargeable lithium-ion electrochemical cells at low temperatures. These and other electrolytes have been investigated in continuing research directed toward extending the lower limit of practical operating temperatures of Li-ion cells down to -60 C. This research at earlier stages was reported in numerous previous NASA Tech Briefs articles, the three most recent being "Ethyl Methyl Carbonate as a Cosolvent for Lithium-Ion Cells" (NPO-20605), Vol. 25, Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells No. 6 (June 2001), page 53; "Alkyl Pyrocarbonate Electrolyte Additives for Li-Ion Cells" (NPO-20775), Vol. 26, No. 5 (May 2002), page 37; and "Fluorinated Alkyl Carbonates as Cosolvents in Li-Ion Cells (NPO-21076), Vol. 26, No. 5 (May 2002), page 38. The present solvent mixtures, in terms of volume proportions of their ingredients, are 1 ethylene carbonate (EC) + 1 diethyl carbonate (DEC) + 1 dimethyl carbonate (DMC) + 3 ethyl methyl carbonate (EMC); 3EC + 3DMC + 14EMC; and 1EC + 1DEC + 1DMC + 4EMC. Relative to similar mixtures reported previously, the present mixtures, which contain smaller proportions of EC, have been found to afford better performance in experimental Li-ion cells at temperatures < -20 C.

High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition

NASA Astrophysics Data System (ADS)

Cui, Linfan; Chen, Jiangtao; Yang, Bingjun; Jiao, Tifeng

2015-12-01

Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on CNT growth, and the field emission properties were optimized. The CNT emitters exhibited excellent field emission performance (the turn-on and threshold fields were 2.1 and 2.4 V/μm, respectively). The largest emission current could reach 70 mA/cm2. The emission current was stable, and no obvious deterioration was observed during the long-term stability test of 50 h. The results were relevant for practical applications based on CNTs.

The rapid growth of vertically aligned carbon nanotubes using laser heating.

PubMed

Park, J B; Jeong, S H; Jeong, M S; Lim, S C; Lee, I H; Lee, Y H

2009-05-06

Growth of densely packed vertically aligned carbon nanotubes (VA-CNTs) using laser-induced chemical vapor deposition with visible laser (lambda = 532 nm) irradiation at room temperature is reported. Using a multiple-catalyst layer (Fe/Al/Cr) on quartz as the substrate and an acetylene-hydrogen mixture as the precursor gas, VA-CNT pillars with 60 microm height and 4 microm diameter were grown at a high rate of around 1 microm s(-1) with good reproducibility. It is demonstrated that the fabrication of uniform pillar arrays of VA-CNTs can be achieved with a single irradiation for each pillar using LCVD with no annealing or preprocessing of the substrate. Here, laser fast heating is considered the primary mechanism facilitating the growth of VA-CNT pillars. Field emission characteristics of an array of VA-CNT pillars were then examined to investigate their potential application in vacuum electronic devices.

Microwave-assisted direct synthesis of butene from high-selectivity methane

PubMed Central

Li, Kang; Lu, Yu-wei

2017-01-01

Methane was directly converted to butene liquid fuel by microwave-induced non-oxidative catalytic dehydrogenation under 0.1–0.2 MPa. The results show that, under microwave heating in a two-stage fixed-bed reactor, in which nickel powder and NiOx–MoOy/SiO2 are used as the catalyst, the methane–hydrogen mixture is used as the raw material, with no acetylene detected. The methane conversion is more than 73.2%, and the selectivity of methane to butene is 99.0%. Increasing the hydrogen/methane feed volume ratio increases methane conversion and selectivity. Gas chromatography/electron impact ionization/mass spectrometry chromatographic analysis showed that the liquid fuel produced by methane dehydrogenation oligomerization contained 89.44% of butene, and the rest was acetic acid, ethanol, butenol and butyric acid, and the content was 1.0–3.0 wt%. PMID:29308261

Separation of C2 hydrocarbons from methane in a microporous metal-organic framework

NASA Astrophysics Data System (ADS)

Tang, Fu-Shun; Lin, Rui-Biao; Lin, Rong-Guang; Zhao, John Cong-Gui; Chen, Banglin

2018-02-01

The recovery of C2 hydrocarbons including acetylene, ethylene and ethane is challenging but important for natural gas upgrading. The separation of C2 hydrocarbons over methane was demonstrated here by using a microporous metal-organic framework [Zn3(OH)2(SDB)2] (H2SDB = 4,4'-sulfonyldibenzoic acid) consisting narrow one-dimensional pore channels. Gas sorption experiments revealed that this MOF material showed considerable uptake capacity for C2H2, C2H4 and C2H6 under ambient conditions, while its capacity for CH4 was very low. High selectivity from IAST calculations for C2H2/CH4, C2H4/CH4 and C2H6/CH4 binary mixtures demonstrated that this MOF material were promising for efficiently separating important separation of C2 hydrocarbons from methane in natural gas processing.

Shock tube study of the fuel structure effects on the chemical kinetic mechanisms responsible for soot formation

NASA Technical Reports Server (NTRS)

Frenklach, M.

1983-01-01

Soot formation in toluene-, benzene-, and acetylene-oxygen-argon mixtures was investigated to study soot formation in a combustion environment. High concentrations of oxygen completely suppress soot formation. The addition of oxygen at relatively low concentrations uniformly suppresses soot formation at high pressures, while at relatively lower pressures it suppresses soot formation at higher temperatures while promoting soot production at lower temperatures. The observed behavior indicates that oxidation reactions compete with ring fragmentation. The main conclusion to be drawn from the results is that the soot formation mechanism is probably the same for the pyrolysis and oxidation of hydrocarbons. That is, the addition of oxygen does not alter the soot route but rather promotes or inhibits this route by means of competitive reactions. An approach to empirical modeling of soot formation during pyrolysis of aromatic hydrocarbons is also presented.

Dangerous mixture of household detergents in an old-style toilet: a case report with simulation experiments of the working environment and warning of potential hazard relevant to the general environment.

PubMed

Minami, M; Katsumata, M; Miyake, K; Inagaki, H; Fan, X H; Kubota, H; Yamano, Y; Kimura, O

1992-01-01

A housewife cleaned toilet porcelain connected directly to a sewage storage tank with a mixture of cleaning agents; sodium hypochlorite (NaOCl) and hydrochloric acid (HCl) solutions. She complained of insomnia on the night after cleaning and suffered from severe metabolic acidosis with extremely low blood pH, PCO2 and bicarbonate values. She recovered from the acidosis after bicarbonate transfusion, plasmapheresis and plasma exchange. Permanent blindness ensued, however, from the third day after the event. These clinical symptoms suggested that the toxic substances responsible were chloramine and methyl chloride. Their generation was confirmed by in-vitro experiments, mixing NaOCl, HCl and pooled urine from normal people. In the simulation, the methyl chloride level far exceeded (100,000 ppm) the maximal allowable concentration recommended (ca 400 ppm) by the American Conference of Governmental Industrial Hygienists (ACGIH). Chloramine's toxic actions were confirmed using purified enzyme assay, and the inhibition of carbonic anhydrase and aldehyde dehydrogenase and the enhancement of superoxide dismutase activity were confirmed in neutral pH. The patient's clinical symptoms suggested that insomnia and permanent blindness seemed to be partly ascribable to chronic repetitive exposure to methyl chloride; catching a cold, drug intake and alcohol intake, in addition, precipitated the patient's visual loss. The possibility of this kind of intoxication with such a mixture of agents may lie latent in any situation where sewage or garbage are exposed to the open air.

Isolation and characterization of a hydrocarbonoclastic bacterial enrichment from total petroleum hydrocarbon contaminated sediments: potential candidates for bioaugmentation in bio-based processes.

PubMed

Di Gregorio, Simona; Siracusa, Giovanna; Becarelli, Simone; Mariotti, Lorenzo; Gentini, Alessandro; Lorenzi, Roberto

2016-06-01

Seven hydrocarbonoclastic new bacterial isolates were isolated from dredged sediments of a river estuary in Italy. The sediments were contaminated by shipyard activities since decades, mainly ascribable to the exploitation of diesel oil as the fuel for recreational and commercial navigation of watercrafts. The bacterial isolates were able to utilize diesel oil as sole carbon source. Their metabolic capacities were evaluated by GC-MS analysis, with reference to the depletion of both the normal and branched alkanes, the nC18 fatty acid methyl ester and the unresolved complex mixture of organic compounds. They were taxonomically identified as different species of Stenotrophomonas and Pseudomonas spp. by the combination of amplified ribosomal DNA restriction analysis (ARDRA) and repetitive sequence-based PCR (REP-PCR) analysis. The metabolic activities of interest were analyzed both in relation to the single bacterial strains and to the combination of the latter as a multibacterial species system. After 6 days of incubation in mineral medium with diesel oil as sole carbon source, the Stenotrophomonas sp. M1 strain depleted 43-46 % of Cn-alkane from C28 up to C30, 70 % of the nC18 fatty acid methyl ester and the 46 % of the unresolved complex mixture of organic compounds. On the other hand, the Pseudomonas sp. NM1 strain depleted the 76 % of the nC18 fatty acid methyl ester, the 50 % of the unresolved complex mixture of organic compounds. The bacterial multispecies system was able to completely deplete Cn-alkane from C28 up to C30 and to deplete the 95 % of the unresolved complex mixture of organic compounds. The isolates, either as single strains and as a bacterial multispecies system, were proposed as candidates for bioaugmentation in bio-based processes for the decontamination of dredged sediments.

Fatal carbon monoxide intoxication after acetylene gas welding of pipes.

PubMed

Antonsson, Ann-Beth; Christensson, Bengt; Berge, Johan; Sjögren, Bengt

2013-06-01

Acetylene gas welding of district heating pipes can result in exposure to high concentrations of carbon monoxide. A fatal case due to intoxication is described. Measurements of carbon monoxide revealed high levels when gas welding a pipe with closed ends. This fatality and these measurements highlight a new hazard, which must be promptly prevented.

7. Photocopy of photograph, U.S. Army, ca. 1943 (original print ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Photocopy of photograph, U.S. Army, ca. 1943 (original print located at Rocky Mountain Arsenal, Commerce City, Colorado). R.M.A. - 521 - ACETYLENE COMPRESSOR HOUSE TOP FL. LOOKING N.W. - Rocky Mountain Arsenal, Acetylene Compressor House, 700 feet South of December Seventh Avenue; 1100 feet East of D Street, Commerce City, Adams County, CO

6. Photocopy of photograph, U.S. Army, ca. 1943 (original print ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Photocopy of photograph, U.S. Army, ca. 1943 (original print located at Rocky Mountain Arsenal, Commerce City, Colorado). R.M.A. - 521 - ACETYLENE COMPRESSOR HOUSE LOOKING SO. EAST. - Rocky Mountain Arsenal, Acetylene Compressor House, 700 feet South of December Seventh Avenue; 1100 feet East of D Street, Commerce City, Adams County, CO

4. Photocopy of photograph, U.S. Army, ca. 1943 (original print ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Photocopy of photograph, U.S. Army, ca. 1943 (original print located at Rocky Mountain Arsenal, Commerce City, Colorado). R.M.A. - 522 - ACETYLENE GENERATOR. - Rocky Mountain Arsenal, White Phosphorous Filling-Acetylene Generation Building-Warehouse, 840 feet South of December Seventh Avenue; 1030 feet East of D Street, Commerce City, Adams County, CO

5. Photocopy of photograph, U.S. Army, ca. 1943 (original print ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Photocopy of photograph, U.S. Army, ca. 1943 (original print located at Rocky Mountain Arsenal, Commerce City, Colorado). R.M.A. - 522 - ACETYLENE GENERATOR LOOKING S.WEST. - Rocky Mountain Arsenal, White Phosphorous Filling-Acetylene Generation Building-Warehouse, 840 feet South of December Seventh Avenue; 1030 feet East of D Street, Commerce City, Adams County, CO

Characterization of the Minimum Energy Paths and Energetics for the reaction of Vinylidene with Acetylene

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Taylor, Peter R.

1995-01-01

The reaction of vinylidene (CH2C) with acetylene may be an initiating reaction in soot formation. We report minimum energy paths and accurate energetics for a pathway leading to vinylacetylene and for a number of isomers Of C4H4. The calculations use complete active space self-consistent field (CASSCF) derivative methods to characterize the stationary points and internally contacted configuration interaction (ICCI) and/or coupled cluster singles and doubles with a perturbational estimate of triple excitations (CCSD(T)) to determine the energetics. We find an entrance channel barrier of about 5 kcal/mol for the addition of vinylidene to acetylene, but no barriers above reactants for the reaction pathway leading to vinylacetylene.

Application of the photoacoustic method to the measurement of acetylene reduction by nitrogenase enzyme

NASA Astrophysics Data System (ADS)

Schramm, D. U.; Sthel, M. S.; Carneiro, L. O.; Franco, A. A.; Campos, A. C.; Vargas, H.

2005-06-01

Nitrogenase is an enzyme responsible for the reduction of the atmospheric N2 into NH4^+, which represents the key entry point of the molecular nitrogen into the biogeochemical cycle of nitrogen. This enzyme is present in the rhizobial bacteroids, which are symbionts in a Leguminosae plant (Acacia Holosericea), and also reduces acetylene into ethylene at the same rate as the nitrogen reduction. Therefore, a CO2 Laser Photoacoustic system was used for detecting and monitoring the ethylene emission by the nitrogenase activity, in the rhizobial symbionts in Acacia Holosericea, when they are confined in test tubes with acetylene at two different volumes (0.1 and 0.5 ml). Ethylene concentrations are also determined in the ppm range.

Synthesis of 3-iodoindoles by the Pd/Cu-catalyzed coupling of N,N-dialkyl-2-iodoanilines and terminal acetylenes, followed by electrophilic cyclization.

PubMed

Yue, Dawei; Yao, Tuanli; Larock, Richard C

2006-01-06

[reaction: see text] 3-Iodoindoles have been prepared in excellent yields by coupling terminal acetylenes with N,N-dialkyl-o-iodoanilines in the presence of a Pd/Cu catalyst, followed by an electrophilic cyclization of the resulting N,N-dialkyl-o-(1-alkynyl)anilines using I2 in CH2Cl2. Aryl-, vinylic-, alkyl-, and silyl-substituted terminal acetylenes undergo this process to produce excellent yields of 3-iodoindoles. The reactivity of the carbon-nitrogen bond cleavage during cyclization follows the following order: Me > n-Bu, Me > Ph, and cyclohexyl > Me. Subsequent palladium-catalyzed Sonogashira, Suzuki, and Heck reactions of the resulting 3-iodoindoles proceed smoothly in good yields.

Selective Methods for C-X Activation in Carbohydrates

DTIC Science & Technology

2013-01-01

system, the major products observed for the hydrosilylation of monosaccharides were n-hexane, 2- and 3-methylpentane. Glucose hydrosilylation could... polysaccharide cellulose reacting faster than unprotected glucose. Complete hydrosilylation of methyl cellulose yielded a similar mixture of alkane products

Monitoring a simple hydrolysis process in an organic solid by observing methyl group rotation.

PubMed

Beckmann, Peter A; Bohen, Joseph M; Ford, Jamie; Malachowski, William P; Mallory, Clelia W; Mallory, Frank B; McGhie, Andrew R; Rheingold, Arnold L; Sloan, Gilbert J; Szewczyk, Steven T; Wang, Xianlong; Wheeler, Kraig A

2017-09-01

We report a variety of experiments and calculations and their interpretations regarding methyl group (CH 3 ) rotation in samples of pure 3-methylglutaric anhydride (1), pure 3-methylglutaric acid (2), and samples where the anhydride is slowly absorbing water from the air and converting to the acid [C 6 H 8 O 3 (1) + H 2 O → C 6 H 10 O 4 (2)]. The techniques are solid state 1 H nuclear magnetic resonance (NMR) spin-lattice relaxation, single-crystal X-ray diffraction, electronic structure calculations in both isolated molecules and in clusters of molecules that mimic the crystal structure, field emission scanning electron microscopy, differential scanning calorimetry, and high resolution 1 H NMR spectroscopy. The solid state 1 H spin-lattice relaxation experiments allow us to observe the temperature dependence of the parameters that characterize methyl group rotation in both compounds and in mixtures of the two compounds. In the mixtures, both types of methyl groups (that is, molecules of 1 and 2) can be observed independently and simultaneously at low temperatures because the solid state 1 H spin-lattice relaxation is appropriately described by a double exponential. We have followed the conversion 1 → 2 over periods of two years. The solid state 1 H spin-lattice relaxation experiments in pure samples of 1 and 2 indicate that there is a distribution of NMR activation energies for methyl group rotation in 1 but not in 2 and we are able to explain this in terms of the particle sizes seen in the field emission scanning electron microscopy images. Copyright © 2017 Elsevier Inc. All rights reserved.

Antiprotozoal and antimicrobial compounds from the plant pathogen Septoria pistaciarum.

PubMed

Kumarihamy, Mallika; Khan, Shabana I; Jacob, Melissa; Tekwani, Babu L; Duke, Stephen O; Ferreira, Daneel; Nanayakkara, N P Dhammika

2012-05-25

Four new 1,4-dihydroxy-5-phenyl-2-pyridinone alkaloids, 17-hydroxy-N-(O-methyl)septoriamycin A (1), 17-acetoxy-N-(O-methyl)septoriamycin A (2), 13-(S)-hydroxy-N-(O-methyl)septoriamycin A (3), and 13-(R)-hydroxy-N-(O-methyl)septoriamycin A (4), together with the known compounds (+)-cercosporin (5), (+)-14-O-acetylcercosporin (6), (+)-di-O-acetylcercosporin (7), lumichrome, and brassicasterol, were isolated from an ethyl acetate extract of a culture medium of Septoria pistaciarum. Methylation of septoriamycin A (8) with diazomethane yielded three di-O-methyl analogues, two of which existed as mixtures of rotamers. We previously reported antimalarial activity of septoriamycin A. This compound also exhibited significant activity against Leishmania donovani promastigotes. Compounds 5-7 showed moderate in vitro activity against L. donovani promastigotes and chloroquine-sensitive (D6) and -resistant (W2) strains of Plasmodium falciparum, whereas compound 5 was fairly active against methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus. Compounds 5-7 also displayed moderate phytotoxic activity against both a dicot (lettuce, Lactuca sativa) and a monocot (bentgrass, Agrostis stolonifera) and cytotoxicity against a panel of cell lines.

An aziridinium ion intermediate in the nitrosation of a hexetidine model.

PubMed

Loeppky, R N; Bae, J Y

1994-01-01

The nitrosation chemistry of 1,3,5-trimethyl-5-aminohexahydropyrimidine (2) has been investigated as a model for the behavior of the antimicrobial agent hexetidine (1) under similar conditions. The reaction of 2 with sodium nitrite in glacial acetic acid gives 4-methyl-4-[(methylnitrosamino)methyl]-3-nitroso-1,3-oxazolidine (4) as the major nitrosamine. This compound arises from a molecular rearrangement which proceeds through the diazotization of the primary amino group followed by intramolecular displacement of nitrogen to generate an aziridinium ion. The N-nitrosooxazolidine 4 forms from the nitrosation of an imidazolidine produced from the aziridinium ring hydrolytic opening. The N-nitrosooxazolidine 4, an isomer, 5-methyl-5-[(methylnitrosamino)methyl]-3-nitroso-1,3-oxazolidine (14), which is not formed in the nitrosation of 2, and an analog 4-methyl-4-[[(2-ethylhexyl)nitrosamino]methyl]-3-nitroso-1,3-oxazolidine (22) have been independently synthesized. The N-nitrosooxazolidine 22 which would be formed from hexetidine is not present in its nitrosation mixture, suggesting the absence of reactive aziridinium ions in that case. The dissimilar nitrosation chemistry of 2 and 1 are discussed.

Synthesis of methyl (13(2)R/S)-alkyl-pyropheophorbide a and a non-epimerized chlorophyll a mimic.

PubMed

Ogasawara, Shin; Tamiaki, Hitoshi

2015-10-15

The (13(2)R/S)-methoxycarbonyl group of methyl pheophorbides a/a' (chlorophyll a/a' derivatives) was converted to methyl, ethyl, propyl, and isopropyl groups through the C13(2)-alkylation under basic conditions followed by pyrolysis in 2,4,6-collidine with lithium iodide. All the resulting products, methyl 13(2)-alkyl-pyropheophorbides a, predominantly gave the (13(2)R)-stereoisomers with about one tenth of the (13(2)S)-epimers. Their stereochemistry was determined by 1D/2D NMR and their optical properties were characterized by visible absorption and circular dichroism spectroscopy. Methyl (13(2)R)-propyl-pyropheophorbide a was converted to (13(2)R)-propyl-pyrochlorophyll a by ester exchanging and magnesium chelating reactions. The synthetic chlorophyll a analogue showed non-epimerization at the 13(2)-position in pyridine-d5 at 40°C, while naturally occurring chlorophyll a was easily epimerized under the same conditions to give its epimeric mixture. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fire extinguishing tests -80 with methyl alcohol gasoline (in MIXED)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmstedt, G.; Ryderman, A.; Carlsson, B.

1980-01-01

Large scale tests and laboratory experiments were carried out for estimating the extinguishing effectiveness of three alcohol resistant aqueous film forming foams (AFFF), two alcohol resistant fluoroprotein foams and two detergent foams in various poolfires: gasoline, isopropyl alcohol, acetone, methyl-ethyl ketone, methyl alcohol and M15 (a gasoline, methyl alcohol, isobutene mixture). The scaling down of large scale tests for developing a reliable laboratory method was especially examined. The tests were performed with semidirect foam application, in pools of 50, 11, 4, 0.6, and 0.25 sq m. Burning time, temperature distribution in the liquid, and thermal radiation were determined. An M15more » fire can be extinguished with a detergent foam, but it is impossible to extinguish fires in polar solvents, such as methyl alcohol, acetone, and isopropyl alcohol with detergent foams, AFFF give the best results, and performances with small pools can hardly be correlated with results from large scale fires.« less

Effect of Acetylene Black Content to Half Cells Li-ion Battery Performance Based on Li4Ti5O12 using Li2CO3 as Lithium Ion Source with Hydrothermal Mechanochemical Process

NASA Astrophysics Data System (ADS)

Priyono, B.; Faizah; Syahrial, A. Z.; Subhan, A.

2017-07-01

Lithium titanate (Li4Ti5O12)/LTO is a promising candidate to be used as anode electrode in Li-ion battery, to replace graphite in Li-ion battery application. Crystal structure of lithium titanate/LTO is more stable or undergoes less strain than graphite during intercalation and de-intercalation process Li+ ions. However, although lithium titanate has good stability, the material has low electrical conductivity and lithium ion diffusion. The purpose of this research is to synthesis the spinel LTO using combinated hydrothermal and mechanochemical processes from xerogel TiO2. Then, to increase the conductivity, in the half-cell battery assembly process it was added acetylene black conductive (AB) additive with various from 10%, to 15% in wt. The LTO obtained were characterized using scanning electron microscope (SEM), X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET). The XRD showed a rutile as minor phase, while SEM showed homogeneous distribution of particle with an average particle size of 0.35 μm. The BET showed that the surface area of LTO formed is 2.26 m2/g. The assembled coin half cells used this Li4Ti5O12 as a cathode and lithium metal foil as the anode were tested using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and charge discharge (CD). The conductivity value obtained from EIS corresponds to the contents of AB. Meanwhile, the CV and CD testing showed that higher percentage of AB causing the decrease of battery specific capacity. The highest specific capacity at the rate of 10C is obtained at the mixture of 10wt% AB with the value of 40.91 mAh/g.

Chromophores from Photolyzed Ammonia Reacting with Acetylene: Application to Jupiter’s Great Red Spot

NASA Astrophysics Data System (ADS)

Carlson, Robert W.; Baines, K. H.; Anderson, M. S.; Filacchione, G.

2012-10-01

The production mechanisms of chromophores at Jupiter, and notably at the Great Red Spot (GRS), have been long-standing puzzles. A clue to the formation of the GRS coloring agent may be the great height of this storm, which can upwell ammonia to pressure levels of a few hundred mbar where solar photons capable of dissociating NH3 penetrate. Acetylene formed at higher altitudes can diffuse down and react with the NH3 photodissociation products, forming a deposit that absorbs in the ultraviolet and visible region (Ferris and Ishikawa, J. Amer. Chem. Soc. 110, 4306-4312, 1988). We have investigated the system NH3 + C2H2 + CH4 using a Zn lamp emitting at 214 nm to produce NH2 + H and subsequent reaction products. The deposits produced in these reactions were analyzed by optical and infrared spectroscopy and soft-ionization (He*) time-of-flight mass spectroscopy. The combination of NH3 + CH4 produced no visibly absorbing material, but NH3 + C2H2 and NH3 + C2H2 + CH4 mixtures both produced a yellow-orange film whose transmission spectra are similar to that of the GRS obtained by Cassini VIMS. Infrared spectra show a strong band at 2056 wavenumbers which may arise from nitrile (-CN), isonitrile (-NC), or diazide (-CNN) functional groups. The high-resolution mass spectra are consistent with compounds of the form CnH2n+1Nm, similar to the products formed in NH3 + CH4 spark discharges (Molton and Ponnamperuma, Icarus 21, 166-174, 1974). We thank NASA's Planetary Atmospheres Program for support.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jimenez-Orozco, Carlos; Florez, Elizabeth; Moreno, Andres

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. It was found that the bonding of acetylene was significantly affected by the electronic and structural properties of the carbide surfaces. The adsorbate interacted with metal and/or carbon sites of the carbide. 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). Adsorption energies, charge density difference plotsmore » and Mulliken charges suggested that the binding of the hydrocarbon to the surface had both ionic and covalent contributions. 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). The obtained results suggest that the δ-MoC(001) surface is expected to have the best performance in selective hydrogenation reactions to convert alkynes into alkenes. Another advantage of δ-MoC(001) is that, after C 2H 2 adsorption, surface carbon sites remain available, which are necessary for H 2 dissociation. Furthermore, these sites were occupied when C 2H 2 was adsorbed on TiC(001) and ZrC(001), limiting their application in the hydrogenation of alkynes.« less

Boron-carbon-silicon polymers and ceramic and a process for the production thereof

NASA Technical Reports Server (NTRS)

Riccitiello, Salvatore (Inventor); Hsu, Ming-Ta (Inventor); Chen, Timothy S. (Inventor)

1992-01-01

The present invention relates to a process for the production of an organoborosilicon preceramic polymer. The polymer is prepared by the reaction of vinylsilane or vinlymethylsilanes (acetylene)silane or acetylene alkyl silanes and borane or borane derivatives. The prepolymer form is pyrolyzed to produce a ceramic article useful in high temperature (e.g., aerospace) or extreme environmental applications.

6. Photocopy of photograph, U.S. Army, ca. 1943 (original print ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Photocopy of photograph, U.S. Army, ca. 1943 (original print located at Rocky Mountain Arsenal, Commerce City, Colorado). R.M.A. - 522 - ACETYLENE GENERATOR LOOKING N.E. 2ND. FL. - Rocky Mountain Arsenal, White Phosphorous Filling-Acetylene Generation Building-Warehouse, 840 feet South of December Seventh Avenue; 1030 feet East of D Street, Commerce City, Adams County, CO

Tracing Acetylene Dissolved in Transformer Oil by Tunable Diode Laser Absorption Spectrum.

PubMed

Ma, Guo-Ming; Zhao, Shu-Jing; Jiang, Jun; Song, Hong-Tu; Li, Cheng-Rong; Luo, Ying-Ting; Wu, Hao

2017-11-02

Dissolved gas analysis (DGA) is widely used in monitoring and diagnosing of power transformer, since the insulation material in the power transformer decomposes gases under abnormal operation condition. Among the gases, acetylene, as a symbol of low energy spark discharge and high energy electrical faults (arc discharge) of power transformer, is an important monitoring parameter. The current gas detection method used by the online DGA equipment suffers from problems such as cross sensitivity, electromagnetic compatibility and reliability. In this paper, an optical gas detection system based on TDLAS technology is proposed to detect acetylene dissolved in transformer oil. We selected a 1530.370 nm laser in the near infrared wavelength range to correspond to the absorption peak of acetylene, while using the wavelength modulation strategy and Herriott cell to improve the detection precision. Results show that the limit of detection reaches 0.49 ppm. The detection system responds quickly to changes of gas concentration and is easily to maintenance while has no electromagnetic interference, cross-sensitivity, or carrier gas. In addition, a complete detection process of the system takes only 8 minutes, implying a practical prospect of online monitoring technology.

Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

NASA Astrophysics Data System (ADS)

Han, Huixian; Li, Anyang; Guo, Hua

2014-12-01

A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S0) electronic state has been constructed by fitting ˜37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm-1. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm-1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.

A density functional theory study on the acetylene cyclotrimerization on Pd-modified Au(111) surface

NASA Astrophysics Data System (ADS)

Ren, Bohua; Dong, Xiuqin; Yu, Yingzhe; Zhang, Minhua

2017-10-01

Calculations based on the first-principle density functional theory were carried out to study the possible acetylene cyclotrimerization reactions on Pd-Au(111) surface and to investigate the effect of Au atom alloying with Pd. The adsorption of C2H2, C4H4, C6H6 and the PDOS of 4d orbitals of surface Pd and Au atoms were studied. The comparison of d-band center of Pd and Au atom before and after C2H2 or C4H4 adsorption suggests that these molecules affect the activity of Pd-Au(111) surface to some degree due to the high binding energy of the adsorption. In our study, the second neighboring Pd ensembles on Pd-Au(111) surface can adsorb two acetylene molecules on parallel-bridge site of two Au atoms and one Pd atom, respectively. Csbnd C bonds are parallel to each other and two acetylenes are adsorbed face to face to produce four-membered ring C4H4 firstly. The geometric effect and electronic effect of Pd-Au(111) surface with the second neighboring Pd ensembles both help to reduce this activation barrier.

Photo- and heterotrophic nitrogenase activity by the cyano-bacterium Nostoc in symbiosis with the bryophyte Anthoceros

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinberg, N.A.; Meeks, J.C.

1987-04-01

In symbiosis with Anthoceros, Nostoc is thought to do little or no photosynthesis. However, light-dependent /sup 14/CO/sub 2/ fixation by symbiotic Nostoc, freshly isolated from pure cultures of the reconstituted Anthoceros-Nostoc association, was 16% of that by free-living Nostoc. A DCMU-resistant mutant of Nostoc was isolated that fixed CO/sub 2/ at rates comparable to wild-type in both symbiotic and free-living growth states. To determine if symbiotic Nostoc can use its photosynthate directly to fix nitrogen, acetylene reduction by Anthoceros associations reconstituted with wild-type Nostoc was compared to associations with the DCMU-resistant mutant. In wild-type Anthoceros-Nostoc acetylene reduction was inhibited 97%more » by 5 ..mu..M DCMU, while inhibition of the DCMU-resistant Nostoc association was only 63%. Additions of glucose, fructose, maltose or sucrose to wild-type associations completely restored DCMU-inhibited acetylene reduction in the light. Acetylene reduction in the dark was stimulated by glucose, attaining 84% of the uninhibited light-dependent value. The authors conclude that symbiotic Nostoc maintains a pool of photosynthate which supports nitrogenase activity. The pool can also be supplemented from plant sources.« less

Groundwater remediation engineering sparging using acetylene--study on the flow distribution of air.

PubMed

Zheng, Yan-Mei; Zhang, Ying; Huang, Guo-Qiang; Jiang, Bin; Li, Xin-Gang

2005-01-01

Air sparging (AS) is an emerging method to remove VOCs from saturated soils and groundwater. Air sparging performance highly depends on the air distribution resulting in the aquifer. In order to study gas flow characterization, a two-dimensional experimental chamber was designed and installed. In addition, the method by using acetylene as the tracer to directly image the gas distribution results of AS process has been put forward. Experiments were performed with different injected gas flow rates. The gas flow patterns were found to depend significantly on the injected gas flow rate, and the characterization of gas flow distributions in porous media was very different from the acetylene tracing study. Lower and higher gas flow rates generally yield more irregular in shape and less effective gas distributions.

Method of preparing thermal insulation for high temperature microwave sintering operations

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Morrow, M.S.

1996-07-16

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering. 1 fig.

Thermal insulation for high temperature microwave sintering operations and method thereof

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Morrow, M.S.

1995-09-12

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering. 1 fig.

Structural studies of the O-specific polysaccharide(s) from the lipopolysaccharide of Azospirillum brasilense type strain Sp7.

PubMed

Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

2013-10-18

Lipopolysaccharide was obtained by phenol-water extraction from dried bacterial cells of Azospirillum brasilense type strain Sp7. Mild acid hydrolysis of the lipopolysaccharide followed by GPC on Sephadex G-50 resulted in a polysaccharide mixture, which was studied by composition and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy. The following polysaccharide structures were established, where italics indicate a non-stoichiometric (∼40%) 2-O-methylation of l-rhamnose. Copyright © 2013 Elsevier Ltd. All rights reserved.

Improved Performance of an Optically Pumped Mid-Infrared Acetylene-Filled Hollow-Core Fiber Laser

NASA Astrophysics Data System (ADS)

Dadashzadeh, Neda

The focus of this research is improving the pulse output energy of a mid-IR pulsed acetylene-filled Hollow-core Optical Fiber Gas LASer (HOFGLAS) system. Pump pulses and acetylene molecules interact with each other inside hollow-core photonic crystal fiber that effectively confines light and allows for strong gain. This results in lasing at 3.11 mum and 3.17 mum lines based on population inversion of acetylene molecules, which are optically pumped at rotational-vibrational overtones near 1.5 mum using 1 ns pulse duration from an optical parametric amplifier (OPA). This acetylene laser operates with no cavity mirrors because of a high gain in a single pass configuration. There are few laser sources in the mid-IR region while there are many applications for having a laser source in this range such as remote sensing, hazardous chemical detection, and breath analysis. This adds to the importance of the acetylene-filled HOFGLAS system. Some of the applications like remote sensing require high power. So, we moved toward power scaling this laser system by optimizing the laser operation through maximizing the OPA alignment to improve its modal content using longer length of fiber to increase the interaction length and improving the beam quality of the mid-IR emissions. The highest pulse energy ever obtained in the 3 microm mid-IR region from the acetylene-filled HOFGLAS after applying the improvements is reported here (1.4 muJ). Higher mid-IR pulse energies can be achieved by improving the pulse energy achievable from the OPA pump source and working with longer pulse duration to decrease the bandwidth of the OPA. This operation demonstrates many novel properties of acetylene-filled pulsed mid-IR hollow-core fiber lasers. The excellent spatial beam quality at highest power and phenomenological scaling of saturation power and efficiency with pressure that we observe point to the promise of power scaling and motivate further development of numerical models of the laser for deeper insight into these effects. M2 measurement method was used to examine spatial beam quality and it was found to be fiber-dependent. For the improved setup, M2 was investigated at several input pump powers in addition to the reproducibility checks. M 2 of 1.14 at the maximum output power motivates for beam combining to scale to higher power. The independence of efficiency on pressure is an evidence for reaching higher mid-IR power at a pressure where saturation behavior does not exist. achieving the highest mid-IR power to date, 1.4 muJ, encourages for building higher power OPA to produce high power mid-IR emissions. Taken as a whole, this laser exhibits novel behavior that motivates both numerical/theoretical investigation and further efforts to scale to higher powers.

Separation of methane-nitrogen mixtures using synthesis vertically aligned carbon nanotube membranes

NASA Astrophysics Data System (ADS)

Gilani, Neda; Daryan, Jafar Towfighi; Rashidi, Alimorad; Omidkhah, Mohammad Reza

2012-03-01

In this paper, capabilities of carbon nanotube (CNT) membranes fabricated in cylindrical pores of anodic aluminum oxide (AAO) substrate to separate the binary mixtures of CH4/N2 are studied experimentally. For this purpose, the permeability and selectivity of three CNT/AAO membranes with different growth time as 6 h, 12 h and 18 h are investigated. CNTs are grown vertically through holes of AAO with average pore diameter of 45 nm by chemical vapor deposition (CVD) of acetylene gas. CNT/AAO membranes with the same CNTs' outer diameters and different inner diameters are synthesized. The AAO are characterized by SEM analysis. In addition, SEM, TEM, BET N2 adsorption analysis and Raman spectroscopy are employed to characterize aligned CNTs. Study on permeability and selectivity of membranes for three binary mixtures of CH4/N2 showed that when the CNT inner diameters are 34 nm and 24 nm, viscous flow is the governing mechanism and insignificant selectivities of 1.2-1.24 are achieved. However, the membrane with CNT inner diameter and wall thickness of 8 nm and 16 nm respectively is considerably selective for CH4 over N2. It was also found that CH4 mole fraction in the feed and upstream feed pressure have major effect on permeability and selectivity. The membrane with 18 h synthesis time showed the selectivity is in the range of 1.8-3.85. The enhancement factor for N2 single gas diffusivity was also found to be about three times larger than that predicted by Knudsen diffusion model.

Agrochemical synergism imposes higher risk to Neotropical bees than to honeybees

PubMed Central

Tomé, Hudson V. V.; Ramos, Gabryele S.; Araújo, Micaele F.; Santana, Weyder C.; Santos, Gil R.; Guedes, Raul Narciso C.; Maciel, Carlos D.; Newland, Philip L.

2017-01-01

Bees are key pollinators whose population numbers are declining, in part, owing to the effects of different stressors such as insecticides and fungicides. We have analysed the susceptibility of the Africanized honeybee, Apis mellifera, and the stingless bee, Partamona helleri, to commercial formulations of the insecticides deltamethrin and imidacloprid. The toxicity of fungicides based on thiophanate-methyl and chlorothalonil were investigated individually and in combination, and with the insecticides. Results showed that stingless bees were more susceptible to insecticides than honeybees. The commercial fungicides thiophanate-methyl or chlorothalonil caused low mortality, regardless of concentration; however, their combination was as toxic as imidacloprid to both species, and over 400-fold more toxic than deltamethrin for A. mellifera. There were highly synergistic effects on mortality caused by interactions in the mixture of imidacloprid and the fungicides thiophanate-methyl, chlorothalonil and the combined fungicide formulation in A. mellifera, and also to a lesser extent in P. helleri. By contrast, mixtures of the deltamethrin and the combined fungicide formulation induced high synergy in P. helleri, but had little effect on the mortality of A. mellifera. Differences in physiology and modes of action of agrochemicals are discussed as key factors underlying the differences in susceptibility to agrochemicals. PMID:28280585

New constituents from noni (Morinda citrifolia) fruit juice.

PubMed

Samoylenko, Volodymyr; Zhao, Jianping; Dunbar, D Chuck; Khan, Ikhlas A; Rushing, James W; Muhammad, Ilias

2006-08-23

Morinda citrifolia L. (Rubiaceae), known as noni, has a long history of traditional use in the Hawaiian and Tahitian islands. More recently, an array of commercial noni fruit juice products are gaining popularity as dietary supplements, with claims of anticancer and immunostimulant activities. The biologically active principles of noni are not fully known. In continuation of work on the isolation of markers from dietary supplements, this paper reports the isolation of three new markers, namely, 1-O-(3'-methylbut-3'-enyl)-beta-D-glucopyranose (1), 1-n-butyl-4-(5'-formyl-2'-furanyl)methyl succinate (2), and 4-epi-borreriagenin (3), together with the known iridoid glycosides asperulosidic acid (4) and deacetylasperulosidic acid (5) and a mixture of 1-n-butyl-4-methyl-2-hydroxysuccinate (6a) and 1-n-butyl-4-methyl-3-hydroxysuccinate (6b), as well as a mixture of alpha- and beta-glucopyranose from noni fruit juice obtained from Puerto Rico. The structures of compounds were based on 1H and 13C NMR, mainly 2D NMR COSY, HMQC, HMBC, and NOESY experiments, and HRMS. Furthermore, samples from fresh-squeezed noni fruit juice from Japan revealed the presence of scopoletin (7), in addition to compounds 1-6, indicating no significant differences in the marker constituents of noni collected from Atlantic and Pacific regions.

Proton conducting gel polyelectrolytes based on 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) copolymers with polyfunctional monomers. Part I. Anhydrous systems

NASA Astrophysics Data System (ADS)

Zygadło-Monikowska, Ewa; Florjańczyk, Zbigniew; Wielgus-Barry, Edyta; Paśniewski, Jarosław

The synthesis of crosslinked gel polyelectrolytes in polar aprotic solvents such as dimethylformamide (DMF) and a DMF and propylene carbonate (PC) mixture has been carried out in the copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) and polyfunctional monomers. N, N‧-Methylene-bis-acrylamide, trioxyethylene dimethacrylate (M n ∼ 330) and trimethylolpropane ethoxylate (14/3 EO/OH) triacrylate were used as crosslinking monomers. The reactions were initiated thermally or by UV irradiation in the presence of Irgacure 184 or methyl benzoin ether. The crosslinking monomer was used in an amount of 0.5-13 wt.%. The effect of the type and concentration of the polyfunctional comonomer and type of solvent on the optical (color, transparency) and mechanical properties as well as the ability to conduct electrical charges have been studied. The application of a DMF and PC mixture enables to obtain transparent systems of good mechanical properties and high ambient temperature ionic conductivity of the order of 10 -3 to 10 -4 S cm -1, slightly lowered as compared with that of gels comprising DMF alone. The conducting properties of crosslinked gels have been compared with that of the AMPSA homopolymer solutions in analogous solvents.

21 CFR 73.30 - Annatto extract.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.30 Annatto extract. (a) Identity. (1) The color additive..., methyl alcohol, methylene chloride, trichloroethylene. (2) Color additive mixtures for food use made with...

21 CFR 73.30 - Annatto extract.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.30 Annatto extract. (a) Identity. (1) The color additive..., methyl alcohol, methylene chloride, trichloroethylene. (2) Color additive mixtures for food use made with...

21 CFR 73.30 - Annatto extract.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.30 Annatto extract. (a) Identity. (1) The color additive..., methyl alcohol, methylene chloride, trichloroethylene. (2) Color additive mixtures for food use made with...

21 CFR 73.30 - Annatto extract.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.30 Annatto extract. (a) Identity. (1) The color additive..., methyl alcohol, methylene chloride, trichloroethylene. (2) Color additive mixtures for food use made with...

21 CFR 73.30 - Annatto extract.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.30 Annatto extract. (a) Identity. (1) The color additive..., methyl alcohol, methylene chloride, trichloroethylene. (2) Color additive mixtures for food use made with...

Transgenerational Actions of Environmental Compounds on Reproductive Disease and Identification of Epigenetic Biomarkers of Ancestral Exposures

PubMed Central

Tracey, Rebecca; Haque, Md. M.; Skinner, Michael K.

2012-01-01

Environmental factors during fetal development can induce a permanent epigenetic change in the germ line (sperm) that then transmits epigenetic transgenerational inheritance of adult-onset disease in the absence of any subsequent exposure. The epigenetic transgenerational actions of various environmental compounds and relevant mixtures were investigated with the use of a pesticide mixture (permethrin and insect repellant DEET), a plastic mixture (bisphenol A and phthalates), dioxin (TCDD) and a hydrocarbon mixture (jet fuel, JP8). After transient exposure of F0 gestating female rats during the period of embryonic gonadal sex determination, the subsequent F1–F3 generations were obtained in the absence of any environmental exposure. The effects on the F1, F2 and F3 generations pubertal onset and gonadal function were assessed. The plastics, dioxin and jet fuel were found to promote early-onset female puberty transgenerationally (F3 generation). Spermatogenic cell apoptosis was affected transgenerationally. Ovarian primordial follicle pool size was significantly decreased with all treatments transgenerationally. Differential DNA methylation of the F3 generation sperm promoter epigenome was examined. Differential DNA methylation regions (DMR) were identified in the sperm of all exposure lineage males and found to be consistent within a specific exposure lineage, but different between the exposures. Several genomic features of the DMR, such as low density CpG content, were identified. Exposure-specific epigenetic biomarkers were identified that may allow for the assessment of ancestral environmental exposures associated with adult onset disease. PMID:22389676

Just Click It: Undergraduate Procedures for the Copper(I)-Catalyzed Formation of 1,2,3-Triazoles from Azides and Terminal Acetylenes

ERIC Educational Resources Information Center

Sharpless, William D.; Peng Wu; Hansen, Trond Vidar; Lindberg, James G.

2005-01-01

The click chemistry uses only the most reliable reactions to build complex molecules from olefins, electrophiles and heteroatom linkers. A variation on Huisgen's azide-alkyne 1,2,3-triazole synthesis, the addition of the copper (I), the premium example of the click reaction, catalyst strongly activates terminal acetylenes towards the 1,3-dipole in…

New Nitration Concepts

DTIC Science & Technology

1987-09-01

CIECLASSiPCAflON DOWNGRAAING SCHEDULE d is trib ut ion unlimited N/A _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 4 PERFORM!NG ORGANIZATION REPORT NUMBER(S) s. moio OGNZTON...substitute nitroso for silicon by reaction of the silylated compound with nitrosonium fluoroborate but time and funding did not permit completion of...acetylenes, 10.8,9 The synthesis is achieved by treating a bis-substituted trialkylsilyl- acetylene with a nitronium ion 3ource (i.e., nitronium tetrafluoro

The Synthesis and Isothermal Aging Behavior of Oxygen-Free Acetylene Terminated Quinoxalines

DTIC Science & Technology

1981-05-01

Sabourin (Reference 10), to the acetylene-terminated quinoxalines which were purified by chromatog- raphy on silica gel. Overall yields, Tg values, onset and...10. E. J. Sabourin , ACS Petroleum Chem. Prep., 24 (1), 233 (1979). 8 AFWAL-TR-81-4004 KEY TO FIGURES 1, 2 AND 3 HCrCC 0 0= 0 W r0 CECH 0 0 N ý IN HCC-N

Kinetics and Structure of Superagglomerates Produced by Silane and Acetylene

NASA Technical Reports Server (NTRS)

Mulholland, G. W.; Hamins, A.; Sivathanu, Y.

1999-01-01

The evolution of smoke in a laminar diffusion flame involves several steps. The first step is particle inception/nucleation in the high-temperature fuel-rich region of the flame followed by surface growth and coagulation/coalescence of the small particles. As the primary spheres grow in size and lose hydrogen, the colliding particles no longer coalesce but retain their identity as a cluster of primary spheres, termed an agglomerate. Finally, in the upper portion of the flame, the particles enter an oxidizing environment which may lead to partial or complete burnout of the agglomerates. Currently there is no quantitative model for describing the growth of smoke agglomerates up to superagglomerates with an overall dimension of 10 microns and greater. Such particles are produced during the burning of acetylene and fuels containing benzene rings such as toluene and polystyrene. In the case of polystyrene, smoke agglomerates in excess of 1 mm have been observed "raining" out from large fires. Evidence of the formation of superagglomerates in a laminar acetylene/air diffusion flame has been recently reported. Acetylene was chosen as the fuel since the particulate loading in acetylene/air diffusion flames is very high. Photographs were obtained by Sorensen using a microsecond xenon lamp of the "stream" of soot just above the flame. For low flow rates of acetylene, only submicrometer soot clusters are produced and they give rise to the homogeneous appearance of the soot stream. When the flow rate is increased to 1.7 cu cm/s, soot clusters up to 10 microns are formed and they are responsible for the graininess and at a flow rate of 3.4 cu cm/s, a web of interconnected clusters as large as the width of the flame is seen. This interconnecting web of superagglomerates is described as a gel state by Sorensen et al (1998). This is the first observation of a gel for a gas phase system. It was observed that this gel state immediately breaks up into agglomerates due to buoyancy induced turbulence and gravitational sedimentation.

The importance of transport property studies for battery electrolytes: revisiting the transport properties of lithium-N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide mixtures.

PubMed

Rüther, Thomas; Kanakubo, Mitsuhiro; Best, Adam S; Harris, Kenneth R

2017-04-19

Transport properties are examined in some detail for samples of the low temperature molten salt N-propyl-N-methyl pyrrolidinium bis(fluorosulfonyl)imide [Pyr 13 ][FSI] from two different commercial suppliers. A similar set of data is presented for two different concentrations of binary lithium-[Pyr 13 ][FSI] salt mixtures from one supplier. A new and significantly different production process is used for the synthesis of Li[FSI] as well as the [Pyr 13 ] + salt used in the mixtures. Results for the viscosity, conductivity, and self-diffusion coefficients, together with the density and expansivity and apparent molar volume, are reported over the temperature range of (0 to 80) °C. The data for neat [Pyr 13 ][FSI] are discussed in the context of velocity cross correlation (VCC or f ij ) and Laity resistance (r ij ) coefficients. Unusually, f +- ∼ f ++ < f -- . The three resistance coefficients are of similar magnitude indicating all three ion-ion interactions contribute to the transport properties, not just the cation-anion interaction. The composition dependence of the transport properties is compared to previously reported data for the same and related compounds: in contrast to high-temperature molten salt mixtures, this is an exponential dependence. The Nernst-Einstein parameter Δ, which contains information on the correlations of the ionic velocities and is determined by differences in the VCC for the various ion-ion combinations, was calculated for both the neat ionic liquid and its binary mixture. It increases with increasing lithium concentration. The new data set also allows some conclusions with regards to the lithium-[FSI] - coordination environment.

Atmospheric Chemistry of Six Methyl-perfluoroheptene-ethers Used as Heat Transfer Fluid Replacement Compounds: Measured OH Radical Reaction Rate Coefficients, Atmospheric Lifetimes, and Global Warming Potentials

NASA Astrophysics Data System (ADS)

Jubb, A. M.; Gierczak, T.; Baasandorj, M.; Waterland, R. L.; Burkholder, J. B.

2013-12-01

Mixtures of methyl-perfluoroheptene-ethers (C7F13OCH3, MPHEs) are currently in use as a replacement for perfluorinated alkane (PFC) and polyether mixtures (both persistent greenhouse gases with atmospheric lifetimes >1000 years) used as heat transfer fluids. Currently, the atmospheric fate of the MPHE isomers are not well characterized, however, reaction with the OH radical is expected to be a dominant tropospheric loss process for these compounds. In order to assess the atmospheric lifetimes and environmental implications of MPHE use, rate coefficients for MPHE isomers' reaction with OH radicals are desired. In the work presented here, rate coefficients, k, for the gas-phase reaction of the OH radical with six MPHEs commonly used in commercial mixtures (isomers and stereoisomers) and their deuterated analogs (d3-MPHE) were determined at 296 K using a relative rate method with combined gas-chromatography/IR spectroscopy detection. A range of OH rate coefficient values was observed, up to a factor of 20× different, between the MPHE isomers with the (E)-stereoisomers exhibiting the greatest reactivity. The measured OH reaction rate coefficients for the d3-MPHE isomers were lower than the observed MPHE values although a large range of k values between isomers was still observed. The reduction in reactivity with deuteration signifies that the MPHE + OH reaction proceeds via both addition to the olefinic C=C bond and H-abstraction from the methyl ester group. OH addition to the C=C bond was determined to be the primary reaction channel. Atmospheric lifetimes with respect to the OH reaction for the six MPHE isomers were found to be in the range of days to months. The short lifetimes indicate that MPHE use will primarily impact tropospheric local and regional air quality. A MPHE atmospheric degradation mechanism will be presented. As part of this work, radiative efficiencies and global warming potentials (GWPs) for the MPHE isomers were estimated based on measured infrared absorption spectra of MPHE mixture samples and infrared spectra calculated theoretically. Here the calculated GWPs for the MPHE isomers are considered to be estimates, as the actual GWPs for short-lived gases will depend greatly on the season and location of their emission. The results presented highlight the importance of quantifying the individual component atmospheric fate for all mixture components when assessing the atmospheric behavior of mixtures.

Propargyl + O 2 Reaction in Helium Droplets: Entrance Channel Barrier or Not?

DOE PAGES

Moradi, Christopher P.; Morrison, Alexander M.; Klippenstein, Stephen J.; ...

2013-09-09

A combination of liquid He droplet experiments and multireference electronic structure calculations is used to probe the potential energy surface for the reaction between the propargyl radical and O 2. Infrared laser spectroscopy is used to probe the outcome of the low temperature, liquid He-mediated reaction. Bands in the spectrum are assigned to the acetylenic CH stretch (ν 1), the symmetric CH 2 stretch (ν 2), and the antisymmetric CH 2 stretch (ν 13) of the trans-acetylenic propargyl peroxy radical (•OO—CH 2—C≡CH). The observed band origins are in excellent agreement with previously reported anharmonic frequency computations for this species. Themore » Stark spectrum of the ν 1 band provides further evidence that the reaction leads only to the trans-acetylenic species. There are no other bands in the CH 2 stretching region that can be attributed to any of the other three propargyl peroxy isomers/conformers that are predicted to be minimum energy structures ( gauche-acetylenic, cis-allenic, and trans-allenic). There is also no evidence for the kinetic stabilization of a van der Waals complex between propargyl and O 2. A combination of multireference and coupled-cluster electronic structure calculations is used to probe the potential energy surface in the neighborhood of the transition state connecting reactants with the acetylenic adduct. The multireference based evaluation of the doublet-quartet splitting added to the coupled-cluster calculated quartet state energies yields what are likely the most accurate predictions for the doublet potential curve. As a result, this calculation suggests that there is no saddle point for the addition process, in agreement with the experimental observations. Other calculations suggest the possible presence of a small submerged barrier.« less

Product toxicity and cometabolic competitive inhibition modeling of chloroform and trichloroethylene transformation by methanotrophic resting cells.

PubMed Central

Alvarez-Cohen, L; McCarty, P L

1991-01-01

The rate and capacity for chloroform (CF) and trichloroethylene (TCE) transformation by a mixed methanotrophic culture of resting cells (no exogenous energy source) and formate-fed cells were measured. As reported previously for TCE, formate addition resulted in an increased CF transformation rate (0.35 day-1 for resting cells and 1.5 day-1 for formate-fed cells) and transformation capacity (0.0065 mg of CF per mg of cells for resting cells and 0.015 mg of CF per mg of cells for formate-fed cells), suggesting that depletion of energy stores affects transformation behavior. The observed finite transformation capacity, even with an exogenous energy source, suggests that toxicity was also a factor. CF transformation capacity was significantly lower than that for TCE, suggesting a greater toxicity from CF transformation. The toxicity of CF, TCE, and their transformation products to whole cells was evaluated by comparing the formate oxidation activity of acetylene-treated cells to that of non-acetylene-treated cells with and without prior exposure to CF or TCE. Acetylene arrests the activity of methane monooxygenase in CF and TCE oxidation without halting cell activity toward formate. Significantly diminished formate oxidation by cells exposed to either CR or TCE without acetylene compared with that with acetylene suggests that the solvents themselves were not toxic under the experimental conditions but their transformation products were. The concurrent transformation of CF and TCE by resting cells was measured, and results were compared with predictions from a competitive-inhibition cometabolic transformation model. The reasonable fit between model predictions and experimental observations was supportive of model assumptions. PMID:1905516

ENHANCED FORMATION OF CHLORINATED PICS BY THE ADDITION OF BROMINE

EPA Science Inventory

A systematic series of experiments were performed on a pilot-scale rotary kiln incinerator simulator in which liquid surrogate wastes containing varied levels of chlorine and bromine were burned. The surrogate wastes used were a series of mixtures of methylene chloride and methyl...

Cloud forming potential of oligomers relevant to secondary organic aerosols

NASA Astrophysics Data System (ADS)

Xu, Wen; Guo, Song; Gomez-Hernandez, Mario; Zamora, Misti L.; Secrest, Jeremiah; Marrero-Ortiz, Wilmarie; Zhang, Annie L.; Collins, Don R.; Zhang, Renyi

2014-09-01

The hygroscopic growth factor (HGF) and cloud condensation nuclei (CCN) activity are measured for surrogates that mimic atmospherically relevant oligomers, including glyoxal trimer dihydrate, methyl glyoxal trimer dihydrate, sucrose, methyl glyoxal mixtures with sulfuric acid and glycolic acid, and 2,4-hexandienal mixtures with sulfuric acid and glycolic acid. For the single-component aerosols, the measured HGF ranges from 1.3 to 1.4 at a relative humidity of 90%, and the hygroscopicity parameter (κ) is in the range of 0.06 to 0.19 on the basis of the measured CCN activity and 0.13 to 0.22 on the basis of the measured HGF, compared to the calculated values of 0.08 to 0.16. Large differences exist in the κ values derived using the measured HGF and CCN data for the multi-component aerosols. Our results reveal that, in contrast to the oxidation process, oligomerization decreases particle hygroscopicity and CCN activity and provides guidance for analyzing the organic species in ambient aerosols.

Cryosolution infrared study of hydrogen bonded halothane acetylene complex

NASA Astrophysics Data System (ADS)

Melikova, S. M.; Rutkowski, K. S.; Rospenk, M.

2018-05-01

The interactions between halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) and acetylene (C2H2) are studied by FTIR spectroscopy. Results obtained in liquid cryosolutions in Kr suggest weak complex formation stabilized by H - bond. The complexation enthalpy (∼11 kJ/mol) is evaluated in a series of temperature measurements (T ∼ 120-160 K) of integrated intensity of selected bands performed in liquefied Kr. The quantum chemical MP2/6-311++G(2d,2p) calculations predict four different structures of the complex. The most stable and populated (94% at T∼120 K) structure corresponds to the H - bond between H atom of halothane and pi-electron of triple bond between C atoms of acetylene. Wave numbers of vibrational bands of the most stable structure are calculated in anharmonic approximation implemented in Gaussian program.

An Approach for Hydrogen Recycling in a Closed-loop Life Support Architecture to Increase Oxygen Recovery Beyond State-of-the-Art

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee; Greenwood, Zachary; Alvarez, Giraldo

2014-01-01

State-of-the-art atmosphere revitalization life support technology on the International Space Station is theoretically capable of recovering 50% of the oxygen from metabolic carbon dioxide via the Carbon Dioxide Reduction Assembly (CRA). When coupled with a Plasma Pyrolysis Assembly (PPA), oxygen recovery increases dramatically, thus drastically reducing the logistical challenges associated with oxygen resupply. The PPA decomposes methane to predominantly form hydrogen and acetylene. Because of the unstable nature of acetylene, a down-stream separation system is required to remove acetylene from the hydrogen stream before it is recycled to the CRA. A new closed-loop architecture that includes a PPA and downstream Hydrogen Purification Assembly (HyPA) is proposed and discussed. Additionally, initial results of separation material testing are reported.

Denitrification in sediments from the hyporheic zone adjacent to a small forested stream

USGS Publications Warehouse

Duff, J.H.; Triska, F.J.

1990-01-01

Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both nitrate and dissolved organic carbon decreased over summer in wells at the base of the alder-forested slope. A 48-h injection of nitrate-amended stream water into hyporheic water 8.4 m inland stimulated nitrous oxide production in the presence of acetylene. Nitrous oxide was generated as nitrate and acetylene were co-transported to a well 13 m down-gradient. Acetylene-block experiments coupled with the chemistry data suggest that denitrification can modify the chemistry of water during passage through the hyporheic zone. -from Authors

Protonation-dissociation reactions of imazamethabenz-methyl and imazamethabenz-Acid in relation to their soil sorption and abiotic degradation.

PubMed

Pintado, Sara; Montoya, Mercedes Ruiz; Mellado, José Miguel Rodríguez

2009-12-09

This paper present ultraviolet-visible absorption spectra of imazamethabenz-methyl (IMBM) (mixture of the isomers methyl 6-[(RS)-4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl]-m-toluate, m-imazamethabenz, and methyl 2-[(RS)-4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl]-p-toluate, p-imazamethabenz) and the corresponding carboxylic acid, imazamethabenz-acid (IMBA). The spectral characteristics are determined as functions of the pH. The appreciable absorbance in the visible (or near-ultraviolet) region of the spectra indicates that the natural photolytic degradation is possible. From variations of the maximum absorbances of the bands, the pK values of 3.4 +/- 0.2 and 9.4 +/- 0.2 were obtained for protonation of the imidazol (=N-) nitrogen and dissociation of the NH imidazol nitrogen of IMBM, respectively. For IMBA, the dissociation pK of the carboxylic group is very close to that of the imidazol (=N-) nitrogen, both being close to 3.3. The dissociation pK of the NH imidazol nitrogen for IMBA is 9.6 +/- 0.2. The role of the acid-base reactions on the sorption on soils of these herbicides is discussed.

Modeling Study of the Low-Temperature Oxidation of Large Methyl Esters from C11 to C19

PubMed Central

Herbinet, Olivier; Biet, Joffrey; Hakka, Mohammed Hichem; Warth, Valérie; Glaude, Pierre Alexandre; Nicolle, André; Battin-Leclerc, Frédérique

2013-01-01

The modeling of the low temperature oxidation of large saturated methyl esters really representative of those found in biodiesel fuels has been investigated. Models have been developed for these species and then detailed kinetic mechanisms have been automatically generated using a new extended version of software EXGAS, which includes reactions specific to the chemistry of esters. A model generated for a binary mixture of n-decane and methyl palmitate was used to simulate experimental results obtained in a jet-stirred reactor for this fuel. This model predicts very well the reactivity of the fuel and the mole fraction profiles of most reaction products. This work also shows that a model for a middle size methyl ester such as methyl decanoate predicts fairly well the reactivity and the mole fractions of most species with a substantial decrease in computational time. Large n-alkanes such as n-hexadecane are also good surrogates for reproducing the reactivity of methyl esters, with an important gain in computational time, but they cannot account for the formation of specific products such as unsaturated esters or cyclic ethers with an ester function. PMID:23814504

Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry.

PubMed

Dron, Julien; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri

2007-12-12

The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF3/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L(-1). Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

Conducting polymer networks synthesized by photopolymerization-induced phase separation

NASA Astrophysics Data System (ADS)

Yamashita, Yuki; Komori, Kana; Murata, Tasuku; Nakanishi, Hideyuki; Norisuye, Tomohisa; Yamao, Takeshi; Tran-Cong-Miyata, Qui

2018-03-01

Polymer mixtures composed of double networks of a polystyrene derivative (PSAF) and poly(methyl methacrylate) (PMMA) were alternatively synthesized by using ultraviolet (UV) and visible (Vis) light. The PSAF networks were generated by UV irradiation to photodimerize the anthracene (A) moieties labeled on the PSAF chains, whereas PMMA networks were produced by photopolymerization of methyl methacrylate (MMA) monomer and the cross-link reaction using ethylene glycol dimethacrylate (EGDMA) under Vis light irradiation. It was found that phase separation process of these networks can be independently induced and promptly controlled by using UV and Vis light. The characteristic length scale distribution of the resulting co-continuous morphology can be well regulated by the UV and Vis light intensity. In order to confirm and utilize the connectivity of the bicontinuous morphology observed by confocal microscopy, a very small amount, 0.1 wt%, of multi-walled carbon nanotubes (MWCNTs) was introduced into the mixture and the current-voltage (I-V) relationship was subsequently examined. Preliminary data show that MWCNTs are preferentially dispersed in the PSAF-rich continuous domains and the whole mixture became electrically conducting, confirming the connectivity of the observed bi-continuous morphology. The experimental data obtained in this study reveal a promising method to design various scaffolds for conducting soft matter taking advantages of photopolymerization-induced phase separation.

A Mixture Modeling Framework for Differential Analysis of High-Throughput Data

PubMed Central

Taslim, Cenny; Lin, Shili

2014-01-01

The inventions of microarray and next generation sequencing technologies have revolutionized research in genomics; platforms have led to massive amount of data in gene expression, methylation, and protein-DNA interactions. A common theme among a number of biological problems using high-throughput technologies is differential analysis. Despite the common theme, different data types have their own unique features, creating a “moving target” scenario. As such, methods specifically designed for one data type may not lead to satisfactory results when applied to another data type. To meet this challenge so that not only currently existing data types but also data from future problems, platforms, or experiments can be analyzed, we propose a mixture modeling framework that is flexible enough to automatically adapt to any moving target. More specifically, the approach considers several classes of mixture models and essentially provides a model-based procedure whose model is adaptive to the particular data being analyzed. We demonstrate the utility of the methodology by applying it to three types of real data: gene expression, methylation, and ChIP-seq. We also carried out simulations to gauge the performance and showed that the approach can be more efficient than any individual model without inflating type I error. PMID:25057284

AB INITIO AND DENSITY FUNCTION ANALYSIS OF THE ACETYLENE + O2(3S) REACTION SYSTEM AND CHEMEMICAL KINETIC EVALUATION OF ACETYLENE + O2(3S), O2(1D) AND VINYLIDENE + O2(3S). (R824970)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Mechanism-based inactivation of cytochrome P-450 dependent benzo(a)pyrene hydroxylase activity by acetylenic and olefinic polycyclic arylhydrocarbons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, L.S.

A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxygenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene (EP), 3-ethynylperylene (EPL), cis- and trans-1-(2-bromo-vinyl)pyrene (c-BVP and t-BVP), and 1-allylpyrene (AP) serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo(a)pyrene (BP) hydroxylase, while 1-vinyl-pyrene (VP) and phenyl 1-pyrenyl acetylene (PPA) do not cause a detectable suicide inhibition of the BP hydroxylase. The mechanism-based loss of BP hydroxylase activity caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes. In themore » presence of NADPH, /sup 3/H-labeled EP covalently attached to P-450 isozymes with a measured stoichiometry of one mole of EP per mole of the P-450 heme. The results of the effects of these aryl derivatives in the mammalian cell-mediated mutagenesis assay and toxicity assay show that none of the compounds examined nor any of the their metabolites produced in the incubation system are cytotoxic to V79 cells.« less

Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Huixian; School of Physics, Northwest University, Xi’an, Shaanxi 710069; Li, Anyang

2014-12-28

A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S{sub 0}) electronic state has been constructed by fitting ∼37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm{sup −1}. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies upmore » to 12 700 cm{sup −1} above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.« less

Effect of injection pressure on performance, emission, and combustion characteristics of diesel-acetylene-fuelled single cylinder stationary CI engine.

PubMed

Srivastava, Anmesh Kumar; Soni, Shyam Lal; Sharma, Dilip; Jain, Narayan Lal

2018-03-01

In this paper, the effect of injection pressure on the performance, emission, and combustion characteristics of a diesel-acetylene fuelled single cylinder, four-stroke, direct injection (DI) diesel engine with a rated power of 3.5 kW at a rated speed of 1500 rpm was studied. Experiments were performed in dual-fuel mode at four different injection pressures of 180, 190, 200, and 210 bar with a flow rate of 120 LPH of acetylene and results were compared with that of baseline diesel operation. Experimental results showed that highest brake thermal efficiency of 27.57% was achieved at injection pressure of 200 bar for diesel-acetylene dual-fuel mode which was much higher than 23.32% obtained for baseline diesel. Carbon monoxide, hydrocarbon, and smoke emissions were also measured and found to be lower, while the NO x emissions were higher at 200 bar in dual fuel mode as compared to those in other injection pressures in dual fuel mode and also for baseline diesel mode. Peak cylinder pressure, net heat release rate, and rate of pressure rise were also calculated and were higher at 200 bar injection pressure in dual fuel mode.

Fabrication and evaluation of polymeric early-warning fire-alarm devices. [combustion products

NASA Technical Reports Server (NTRS)

Senturia, S. D.

1975-01-01

The electrical resistivities were investigated of some polymers known to be enhanced by the presence of certain gases. This was done to make a device capable of providing early warning to fire through its response with the gases produced in the early phases of combustion. Eight polymers were investigated: poly(phenyl acetylene), poly(p-aminophenyl acetylene), poly(p-nitrophenyl acetylene), poly(p-formamidophenyl acetylene), poly(ethynyl ferrocene), poly(ethynyl carborane), poly(ethynyl pyridine), and the polymer made from 1,2,3,6 tetramethyl pyridazine. A total of 40 usable thin-film sandwich devices and a total of 70 usable interdigitated-electrode lock-and-key devices were fabricated. The sandwich devices were used for measurements of contact linearity, polymer conductivity, and polymer dielectric constant. The lock-and-key devices were used to determine the response of the polymers to a spectrum of gases that included ammonia, carbon nonoxide, carbon dioxide, sulfur dioxide, ethylene, acrolein, water vapor, and normal laboratory air. Strongest responses were to water vapor, ammonia, and acrolein, and depending on the polymer, weaker responses to carbon dioxide, sulfur dioxide, and carbon monoxide were observed. A quantitative theory of device operation, capable of accounting for observed device leakage current and sensitivity, was developed. A prototype detection/alarm system was designed and built for use in demonstrating sensor performance.

Promising SiC support for Pd catalyst in selective hydrogenation of acetylene to ethylene

NASA Astrophysics Data System (ADS)

Guo, Zhanglong; Liu, Yuefeng; Liu, Yan; Chu, Wei

2018-06-01

In this study, SiC supported Pd nanoparticles were found to be an efficient catalyst in acetylene selective hydrogenation reaction. The ethylene selectivity can be about 20% higher than that on Pd/TiO2 catalyst at the same acetylene conversion at 90%. Moreover, Pd/SiC catalyst showed a stable catalytic life at 65 °C with 80% ethylene selectivity. With the detailed characterization using temperature-programmed reduction (H2-TPR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption analysis, CO-chemisorption and thermo-gravimetric analysis (TGA), it was found that SiC owns a lower surface area (22.9 m2/g) and a broad distribution of meso-/macro-porosity (from 5 to 65 nm), which enhanced the mass transfer during the chemical process at high reaction rate and decreased the residence time of ethylene on catalyst surface. Importantly, SiC support has the high thermal conductivity, which favored the rapid temperature homogenization through the catalyst bed and inhabited the over-hydrogenation of acetylene. The surface electronic density of Pd on Pd/SiC catalyst was higher than that on Pd/TiO2, which could promote desorption of ethylene from surface of the catalyst. TGA results confirmed a much less coke deposition on Pd/SiC catalyst.

Gelation of Oil Slicks by Amine Carbamates as an Adjunct to U.S. Navy Oil Spill Recovery Operations

DTIC Science & Technology

1977-01-14

plan for a field test in Boston Harbor was to be developed and submitted to the EPA, Coast Guard, state and municipal water control authorities. Di ...Residual Special Fuel Oil #6, and similar oils) was found to be a mixture of 40 g. dodecylamine, 25 R. tetradecylamine, and 4.5 g. hexadecylamine In...solution with 100 g. methyl alcohol. By far the best system, however, was a mixture of 70% dehydroabletylamine ("Amine D", as manufactured by Hercules Corp

Pulmonary granulomas of guinea pigs induced by inhalation exposure of heat-treated BCG Pasteur, purified trehalose dimycolate and methyl ketomycolate.

PubMed

Sugawara, I; Udagawa, T; Hua, S C; Reza-Gholizadeh, M; Otomo, K; Saito, Y; Yamada, H

2002-02-01

This study was designed to determine the identity of granulomatogenic substances in Mycobacterium bovis BCG Pasteur. When heat-treated BCG Pasteur bacilli were introduced into the lungs of guinea-pigs by an inhalation exposure apparatus, pulmonary granulomas without necrosis developed. Furthermore, when four kinds of mycolates derived from M. tuberculosis Aoyama B strain were introduced into the lungs by the same method, only trehalose 6,6'-dimycolate (TDM) and methyl ketomycolate induced pulmonary granulomas without central necrosis. The pulmonary granulomas consisted of epithelioid macrophages and lymphocytes. When a mixture of TDM and anti-TDM antibody was introduced into the lungs, development of granulomatous lesions was reduced. These data indicate that TDM and methyl ketomycolate are potent granulomatogenic reagents.

Synthesis and tribological investigation of lipoyl glycerides

USDA-ARS?s Scientific Manuscript database

Lipoyl glycerides (LG) were synthesized by enzymatic transesterification of lipoic acid (LA) with high oleic sunflower oil (HOSuO) in 2-methyl-2-butanol solvent. The synthesis gave a crude product mixture (LGc) comprising unreacted LA, free fatty acids (FFA), and various LG structures with varying d...

Lithium insertion in graphite from ternary ionic liquid-lithium salt electrolytes. I. Electrochemical characterization of the electrolytes

NASA Astrophysics Data System (ADS)

Appetecchi, Giovanni B.; Montanino, Maria; Balducci, Andrea; Lux, Simon F.; Winterb, Martin; Passerini, Stefano

In this paper we report the results of chemical-physical investigation performed on ternary room temperature ionic liquid-lithium salt mixtures as electrolytes for lithium-ion battery systems. The ternary electrolytes were made by mixing N-methyl- N-propyl pyrrolidinium bis(fluorosulfonyl) imide (PYR 13FSI) and N-butyl- N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR 14TFSI) ionic liquids with lithium hexafluorophosphate (LiPF 6) or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The mixtures were developed based on preliminary results on the cyclability of graphite electrodes in the IL-LiX binary electrolytes. The results clearly show the beneficial synergic effect of the two ionic liquids on the electrochemical properties of the mixtures.

In Situ Treatment of Chlorinated Ethene-Contaminated Groundwater Using horizontal Flow Treatment Wells.

DTIC Science & Technology

2000-03-01

groundwater, Environmental Science and Technology, 30 (12): 536A-539A, 1996. Arnold, W. A. and A. L. Roberts, Pathways of chlorinated ethylene and...chlorinated acetylene reaction with Zn(0), Environmental Science and Technology, 32 (19): 3017-3025, 1998. Arnold, W. A. and A. L. Roberts, Pathways and...kinetics of chlorinated ethylene and chlorinated acetylene reaction with Fe(0) particles, Environmental Science and Technology, in press, 2000

Sequential allylic substitution/Pauson-Khand reaction: a strategy to bicyclic fused cyclopentenones from MBH-acetates of acetylenic aldehydes.

PubMed

Raji Reddy, Chada; Kumaraswamy, Paridala; Singarapu, Kiran K

2014-09-05

An efficient approach for the construction of novel bicyclic fused cyclopentenones starting from Morita-Baylis-Hillman (MBH) acetates of acetylenic aldehydes with flexible scaffold diversity has been achieved using a two-step reaction sequence involving allylic substitution and the Pauson-Khand reaction. This strategy provided a facile access to various bicyclic cyclopentenones fused with either a carbocyclic or a heterocyclic ring system in good yield.

Low Cost Aromatic Acetylene and Oligomeric Benzils and Their Conversion to Acetylene Terminated Quinoxalines

DTIC Science & Technology

1982-07-01

palladium acetate and the appropriate phosphine . This procedure is known to be effective for bromoarenes. In the early screen- ing runs, 4...Delaware), he indicated that he also had screened many phosphines , and the likelihood of success was very small. Dr. Heck reported that the palladium...any simple modification of the palla- dium phosphine catalyst system will effect the desired reaction. 5 III. PREPARATION OF OLIGOMERIC BENZILS AND

The ozone acetylene reaction: concerted or non-concerted reaction mechanism? A quantum chemical investigation

NASA Astrophysics Data System (ADS)

Cremer, Dieter; Kraka, Elfi; Crehuet, Ramon; Anglada, Josep; Gräfenstein, Jürgen

2001-10-01

The ozone-acetylene reaction is found to proceed via an intermediate van der Waals complex (rather than a biradical), which is the precursor for a concerted symmetry-allowed [4+2] cycloaddition reaction leading to 1,2,3-trioxolene. CCSD(T)/6-311G+(2d, 2p) and CCSD(T)/CBS (complete basis set) calculations predict the ozone-acetylene van der Waals complex to be stable by 2.2 kcal mol -1, the calculated activation enthalpy for the cycloaddition reaction is 9.6 kcal mol -1 and the reaction enthalpy -55.5 kcal mol -1. Calculated kinetic data for the overall reaction ( k=0.8 l mol -1 s-1, A=1.71×10 6 l mol -1 s-1, E a=8.6 kcal mol -1) suggest that there is a need for refined kinetic measurements.

Isotope effect in normal-to-local transition of acetylene bending modes

DOE PAGES

Ma, Jianyi; Xu, Dingguo; Guo, Hua; ...

2012-01-01

The normal-to-local transition for the bending modes of acetylene is considered a prelude to its isomerization to vinylidene. Here, such a transition in fully deuterated acetylene is investigated using a full-dimensional quantum model. It is found that the local benders emerge at much lower energies and bending quantum numbers than in the hydrogen isotopomer HCCH. This is accompanied by a transition to a second kind of bending mode called counter-rotator, again at lower energies and quantum numbers than in HCCH. These transitions are also investigated using bifurcation analysis of two empirical spectroscopic fitting Hamiltonians for pure bending modes, which helpsmore » to understand the origin of the transitions semiclassically as branchings or bifurcations out of the trans and normal bend modes when the latter become dynamically unstable. The results of the quantum model and the empirical bifurcation analysis are in very good agreement.« less

Development of a spectrofluorimetry-based device for determining the acetylene content in the oils of power transformers.

PubMed

Quintella, Cristina M; Meira, Marilena; Silva, Weidson Leal; Filho, Rogério G D; Araújo, André L C; Júnior, Elias T S; Sales, Lindolfo J O

2013-12-15

Power transformers are essential for a functioning electrical system and therefore require special attention by maintenance programs because a fault can harm both the company and society. The temperature inside a power transformer and the dissolved gases, which are primarily composed of acetylene, are the two main parameters monitored when detecting faults. This paper describes the development of a device for analyzing the acetylene content in insulating oil using spectrofluorimetry. Using this device introduces a new methodology for the maintaining and operating power transformers. The prototype is currently operating in a substation. The results presented by this system were satisfactory; when compared to chromatographic data, the errors did not exceed 15%. This prototype may be used to confirm the quality of an insulating oil sample to detect faults in power transformers. © 2013 Elsevier B.V. All rights reserved.

Method to grow carbon thin films consisting entirely of diamond grains 3-5 nm in size and high-energy grain boundaries

DOEpatents

Carlisle, John A.; Auciello, Orlando; Birrell, James

2006-10-31

An ultrananocrystalline diamond (UNCD) having an average grain size between 3 and 5 nanometers (nm) with not more than about 8% by volume diamond having an average grain size larger than 10 nm. A method of manufacturing UNCD film is also disclosed in which a vapor of acetylene and hydrogen in an inert gas other than He wherein the volume ratio of acetylene to hydrogen is greater than 0.35 and less than 0.85, with the balance being an inert gas, is subjected to a suitable amount of energy to fragment at least some of the acetylene to form a UNCD film having an average grain size of 3 to 5 nm with not more than about 8% by volume diamond having an average grain size larger than 10 nm.

Nitrogen-doped Carbon Derived from ZIF-8 as a High-performance Metal-free Catalyst for Acetylene Hydrochlorination

NASA Astrophysics Data System (ADS)

Chao, Songlin; Zou, Fang; Wan, Fanfan; Dong, Xiaobin; Wang, Yanlin; Wang, Yuxuan; Guan, Qingxin; Wang, Guichang; Li, Wei

2017-01-01

Acetylene hydrochlorination is a major industrial technology for manufacturing vinyl chloride monomer in regions with abundant coal resources; however, it is plagued by the use of mercury(II) chloride catalyst. The development of a nonmercury catalyst has been extensively explored. Herein, we report a N-doped carbon catalyst derived from ZIF-8 with both high activity and quite good stability. The acetylene conversion reached 92% and decreased slightly during a 200 h test at 220 °C and atmospheric pressure. Experimental studies and theoretical calculations indicate that C atoms adjacent to the pyridinic N are the active sites, and coke deposition covering pyridinic N is the main reason for catalyst deactivation. The performance of those N-doped carbons makes it possible for practical applications with further effort. Furthermore, the result also provides guidance for designing metal-free catalysts for similar reactions.

Characterization of the Minimum Energy Paths for the Reactions of CH(X(sup 2 Pi) and (1)CH2 with C2H2

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

1994-01-01

The reactions of CH(sup 2 Pi) and singlet methylene (1)CH2 with acetylene lead to intermediates which may be important in soot formation. CH(sup 2 Pi) + acetylene leads to CHCHCH (C3H3), CHCCH (C3H2), and propargyl (CH2CCH). (1)CH2 + acetylene leads to cyclopropene and propargyl. All of these reaction products are formed with no barrier. Miller and Melius have previously discussed the dimerization of propargyl to give benzene. C3H3 and C3H2 can dimerize with no barrier to give benzene and para-benzyne, respectively. C3H3 and C3H2 can also add to smaller polynuclear aromatic hydrocarbons (PAH), and may be important species in forming larger PAH or fullerenes.

Selective enhancement of fentanyl-induced antinociception by the delta agonist SNC162 but not by ketamine in rhesus monkeys: Further evidence supportive of delta agonists as candidate adjuncts to mu opioid analgesics.

PubMed

Banks, Matthew L; Folk, John E; Rice, Kenner C; Negus, S Stevens

2010-12-01

Mu-opioid receptor agonists such as fentanyl are effective analgesics, but their clinical use is limited by untoward effects. Adjunct medications may improve the effectiveness and/or safety of opioid analgesics. This study compared interactions between fentanyl and either the noncompetitive N-methyl-D-aspartate (NMDA) glutamate receptor antagonist ketamine or the delta-opioid receptor agonist SNC162 [(+)-4-[(alphaR)-alpha-[(2S,5R)-2,5-dimethyl-4-(2-propenyl)-1-piperazinyl]-(3-phenyl)methyl]-N,N-diethylbenzamide] in two behavioral assays in rhesus monkeys. An assay of thermal nociception evaluated tail-withdrawal latencies from water heated to 50 and 54°C. An assay of schedule-controlled responding evaluated response rates maintained under a fixed-ratio 30 schedule of food presentation. Effects of each drug alone and of three mixtures of ketamine+fentanyl (22:1, 65:1, 195:1 ketamine/fentanyl) or SNC162+fentanyl (59:1, 176:1, 528:1 SNC162/fentanyl) were evaluated in each assay. All drugs and mixtures dose-dependently decreased rates of food-maintained responding, and drug proportions in the mixtures were based on relative potencies in this assay. Ketamine and SNC162 were inactive in the assay of thermal antinociception, but fentanyl and all mixtures produced dose-dependent antinociception. Drug interactions were evaluated using dose-addition and dose-ratio analysis. Dose-addition analysis revealed that interactions for all ketamine/fentanyl mixtures were additive in both assays. SNC162/fentanyl interactions were usually additive, but one mixture (176:1) produced synergistic antinociception at 50°C. Dose-ratio analysis indicated that ketamine failed to improve the relative potency of fentanyl to produce antinociception vs. rate suppression, whereas two SNC162/fentanyl mixtures (59:1 and 176:1) increased the relative potency of fentanyl to produce antinociception. These results suggest that delta agonists may produce more selective enhancement than ketamine of mu agonist-induced antinociception. Copyright © 2010 Elsevier Inc. All rights reserved.

C-C bond formation and related reactions at the CNC backbone in (smif)FeX (smif = 1,3-di-(2-pyridyl)-2-azaallyl): dimerizations, 3 + 2 cyclization, and nucleophilic attack; transfer hydrogenations and alkyne trimerization (X = N(TMS)2, dpma = (di-(2-pyridyl-methyl)-amide)).

PubMed

Frazier, Brenda A; Williams, Valerie A; Wolczanski, Peter T; Bart, Suzanne C; Meyer, Karsten; Cundari, Thomas R; Lobkovsky, Emil B

2013-03-18

Molecular orbital analysis depicts the CNC(nb) backbone of the smif (1,3-di-(2-pyridyl)-2-azaallyl) ligand as having singlet diradical and/or ionic character where electrophilic or nucleophilic attack is plausible. Reversible dimerization of (smif)Fe{N(SiMe3)2} (1) to [{(Me3Si)2N}Fe]2(μ-κ(3),κ(3)-N,py2-smif,smif) (2) may be construed as diradical coupling. A proton transfer within the backbone-methylated, and o-pyridine-methylated smif of putative ((b)Me2(o)Me2smif)FeN(SiMe3)2 (8) provides a route to [{(Me3Si)2N}Fe]2(μ-κ(4),κ(4)-N,py2,C-((b)Me,(b)CH2,(o)Me2(smif)H))2 (9). A 3 + 2 cyclization of ditolyl-acetylene occurs with 1, leading to the dimer [{2,5-di(pyridin-2-yl)-3,4-di-(p-tolyl-2,5-dihydropyrrol-1-ide)}FeN(SiMe3)2]2 (11), and the collateral discovery of alkyne cyclotrimerization led to a brief study that identified Fe(N(SiMe3)2(THF) as an effective catalyst. Nucleophilic attack by (smif)2Fe (13) on (t)BuNCO and (2,6-(i)Pr2C6H3)NCO afforded (RNHCO-smif)2Fe (14a, R = (t)Bu; 14b, 2,6-(i)PrC6H3). Calculations suggested that (dpma)2Fe (15) would favorably lose dihydrogen to afford (smif)2Fe (13). H2-transfer to alkynes, olefins, imines, PhN═NPh, and ketones was explored, but only stoichiometric reactions were affected. Some physical properties of the compounds were examined, and X-ray structural studies on several dinuclear species were conducted.

Investigating Titan's Atmospheric Chemistry at Low Temperature in Support of the NASA Cassini Mission

NASA Technical Reports Server (NTRS)

Sciamma-O'Brien, Ella; Salama, Farid

2013-01-01

Titan's atmosphere, composed mainly of N2 and CH4, is the siege of a complex chemistry induced by solar UV radiation and electron bombardment from Saturn's magnetosphere. This organic chemistry occurs at temperatures lower than 200 K and leads to the production of heavy molecules and subsequently solid aerosols that form the orange haze surrounding Titan. The Titan Haze Simulation (THS) experiment has been developed on the COSMIC simulation chamber at NASA Ames in order to study the different steps of Titan's atmospheric chemistry at low temperature and to provide laboratory data in support for Cassini data analysis. The chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas mixture is adiabatically cooled to Titan-like temperature (approx. 150 K) before inducing the chemistry by plasma discharge. Different gas mixtures containing N2, CH4, and the first products of the N2,-CH4 chemistry (C2H2, C2H4, C6H6...) but also heavier molecules such as PAHs or nitrogen containing PAHs can be injected. Both the gas phase and solid phase products resulting from the plasma-induced chemistry can be monitored and analyzed. Here we present the results of recent gas phase and solid phase studies that highlight the chemical growth evolution when injecting heavier hydrocarbon trace elements in the initial N2-CH4 mixture. Due to the short residence time of the gas in the plasma discharge, only the first steps of the chemistry have time to occur in a N2-CH4 discharge. However by adding acetylene and benzene to the initial N2-CH4 mixture, we can study the intermediate steps of Titan's atmospheric chemistry as well as specific chemical pathways. These results show the uniqueness of the THS experiment to help understand the first and intermediate steps of Titan fs atmospheric chemistry as well as specific chemical pathways leading to Titan fs haze formation.

Low-void polyimide resins for autoclave processing

NASA Technical Reports Server (NTRS)

Jones, R. J.; Vaughan, R. W.

1972-01-01

Development of an advanced A-type polyimide, which can be used to produce autoclave molded, low-void content composites suitable for use at temperatures up to 316 C is reported. It consists of a mixture of methyl nadic anhydride, an 80:20 molar ratio of methylene dianaline and thiodianilene, and pyromellitic dianhydride.

Persulfate Oxidation of MTBE- and Chloroform-Spent Granular Activated Carbon

EPA Science Inventory

Activated persulfate (Na2S2O8) regeneration of methyl tert-butyl ether (MTBE) and chloroform-spent GAC was evaluated in this study. Thermal-activation of persulfate was effective and resulted in greater MTBE removal than either alkaline-activation or H2O2–persulfate binary mixtur...

Biodegradation and environmental behavior of biodiesel mixtures in the sea: An initial study.

PubMed

DeMello, Jared A; Carmichael, Catherine A; Peacock, Emily E; Nelson, Robert K; Samuel Arey, J; Reddy, Christopher M

2007-07-01

Biodiesel, a mixture of fatty acid methyl esters (FAMEs) derived from animal fats or vegetable oils, is rapidly moving towards the mainstream as an alternative source of energy. However, the behavior of biodiesel, or blends of biodiesel with fossil diesel, in the marine environment have yet to be fully understood. Hence, we performed a series of initial laboratory experiments and simple calculations to evaluate the microbial and environmental fate of FAMEs. Aerobic seawater microcosms spiked with biodiesel or mixtures of biodiesel and fossil diesel revealed that the FAMEs were degraded at roughly the same rate as n-alkanes, and more rapidly than other hydrocarbon components. The residues extracted from these different microcosms became indistinguishable within weeks. Preliminary results from physical-chemical calculations suggest that FAMEs in biodiesel mixtures will not affect the evaporation rates of spilled petroleum hydrocarbons but may stabilize oil droplets in the water column and thereby facilitate transport.

Environmentally Induced Epigenetic Transgenerational Inheritance of Ovarian Disease

PubMed Central

Nilsson, Eric; Larsen, Ginger; Manikkam, Mohan; Guerrero-Bosagna, Carlos; Savenkova, Marina I.; Skinner, Michael K.

2012-01-01

The actions of environmental toxicants and relevant mixtures in promoting the epigenetic transgenerational inheritance of ovarian disease was investigated with the use of a fungicide, a pesticide mixture, a plastic mixture, dioxin and a hydrocarbon mixture. After transient exposure of an F0 gestating female rat during embryonic gonadal sex determination, the F1 and F3 generation progeny adult onset ovarian disease was assessed. Transgenerational disease phenotypes observed included an increase in cysts resembling human polycystic ovarian disease (PCO) and a decrease in the ovarian primordial follicle pool size resembling primary ovarian insufficiency (POI). The F3 generation granulosa cells were isolated and found to have a transgenerational effect on the transcriptome and epigenome (differential DNA methylation). Epigenetic biomarkers for environmental exposure and associated gene networks were identified. Epigenetic transgenerational inheritance of ovarian disease states was induced by all the different classes of environmental compounds, suggesting a role of environmental epigenetics in ovarian disease etiology. PMID:22570695

Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

PubMed

Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

2002-10-01

The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.

Renewable Gasoline, Solvents, and Fuel Additives from 2,3-Butanediol.

PubMed

Harvey, Benjamin G; Merriman, Walter W; Quintana, Roxanne L

2016-07-21

2,3-Butanediol (2,3-BD) is a renewable alcohol that can be prepared in high yield from biomass sugars. 2,3-BD was selectively dehydrated in a solvent-free process to a complex mixture of 2-ethyl-2,4,5-trimethyl-1,3-dioxolanes and 4,5-dimethyl-2isopropyl dioxolanes with the heterogeneous acid catalyst Amberlyst-15. The purified dioxolane mixture exhibited an anti-knock index of 90.5, comparable to high octane gasoline, and a volumetric net heat of combustion 34 % higher than ethanol. The solubility of the dioxolane mixture in water was only 0.8 g per 100 mL, nearly an order of magnitude lower than the common gasoline oxygenate methyl tert-butyl ether. The dioxolane mixture has potential applications as a sustainable gasoline blending component, diesel oxygenate, and industrial solvent. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of methyl mercury in combination with polychlorinated biphenyls and brominated flame retardants on the uptake of glutamate in rat brain synaptosomes: a mathematical approach for the study of mixtures.

PubMed

Stavenes Andersen, Ingrid; Voie, Oyvind Albert; Fonnum, Frode; Mariussen, Espen

2009-11-01

Regulatory limit values for toxicants are in general determined by the toxicology of the single compounds. However, little is known about their combined effects. Methyl mercury (MeHg), polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs) are dominant contaminants in the environment and food. MeHg is a well known neurotoxicant, especially affecting the developing brain. There is increasing evidence that PCB and BFRs also have neurotoxic effects. An enhanced effect of these toxicants, due to either synergistic or additive effects, would be considered as a risk for the fetal development. Here we studied the combinatorial effects of MeHg in combination with PCB or BFR on the reuptake of glutamate in synaptosomes. To provide the optimal conclusion regarding type of interaction, we have analyzed the data using two mathematical models, the Löewe model of additivity and Bliss' model of independent action. Binary and ternary mixtures in different proportions were made. The toxicants had primarily additive effects, as shown with both models, although tendencies towards synergism were observed. MeHg was by far the most potent inhibitor of uptake with an EC(50) value of 0.33 microM. A reconstituted mixture from a relevant fish sample was made in order to elucidate which chemical was responsible for the observed effect. Some interaction was experienced between PCB and MeHg, but in general MeHg seemed to explain the observed effect. We also show that mixture effects should not be assessed by effect addition.

A 5-mC Dot Blot Assay Quantifying the DNA Methylation Level of Chondrocyte Dedifferentiation In Vitro.

PubMed

Jia, Zhaofeng; Liang, Yujie; Ma, Bin; Xu, Xiao; Xiong, Jianyi; Duan, Li; Wang, Daping

2017-05-17

The dedifferentiation of hyaline chondrocytes into fibroblastic chondrocytes often accompanies monolayer expansion of chondrocytes in vitro. The global DNA methylation level of chondrocytes is considered to be a suitable biomarker for the loss of the chondrocyte phenotype. However, results based on different experimental methods can be inconsistent. Therefore, it is important to establish a precise, simple, and rapid method to quantify global DNA methylation levels during chondrocyte dedifferentiation. Current genome-wide methylation analysis techniques largely rely on bisulfite genomic sequencing. Due to DNA degradation during bisulfite conversion, these methods typically require a large sample volume. Other methods used to quantify global DNA methylation levels include high-performance liquid chromatography (HPLC). However, HPLC requires complete digestion of genomic DNA. Additionally, the prohibitively high cost of HPLC instruments limits HPLC's wider application. In this study, genomic DNA (gDNA) was extracted from human chondrocytes cultured with varying number of passages. The gDNA methylation level was detected using a methylation-specific dot blot assay. In this dot blot approach, a gDNA mixture containing the methylated DNA to be detected was spotted directly onto an N + membrane as a dot inside a previously drawn circular template pattern. Compared with other gel electrophoresis-based blotting approaches and other complex blotting procedures, the dot blot method saves significant time. In addition, dot blots can detect overall DNA methylation level using a commercially available 5-mC antibody. We found that the DNA methylation level differed between the monolayer subcultures, and therefore could play a key role in chondrocyte dedifferentiation. The 5-mC dot blot is a reliable, simple, and rapid method to detect the general DNA methylation level to evaluate chondrocyte phenotype.

Exploiting basic principles to control the selectivity of the vapor phase catalytic oxidative cross-coupling of primary alcohols over nanoporous gold catalysts

DOE PAGES

Wang, Lu-Cun; Stowers, Kara J.; Zugic, Branko; ...

2015-05-20

It is important to achieve high selectivity for high volume chemical synthesis in order to lower energy consumption through reduction in waste. Here, we report the selective synthesis of methyl esters—methyl acetate and methyl butyrate—through catalytic O 2-assisted cross-coupling of methanol with ethanol or 1-butanol using activated, support-free nanoporous gold (npAu). Both well-controlled studies on ingots in UHV and experiments under ambient pressure catalytic conditions on both ingots and microspherical hollow shell catalysts reveal guiding principles for controlling selectivity. Under UHV conditions, the ester products of the cross-coupling of methanol with both ethanol and 1-butanol evolve near room temperature inmore » temperature-programmed reaction studies, indicating that the reactions occur facilely. Furthermore, under steady-state catalytic operation, high stable activity was observed for cross-coupling in flowing gaseous reactant mixtures at atmospheric pressure and 423 K with negligible combustion. Optimum selectivity for cross-coupling is obtained in methanol-rich mixtures due to a combination of two factors: (1) the relative coverage of the respective alkoxys and (2) the relative facility of their β-H elimination. The relative coverage of the alkoxys is governed by van der Waal’s interactions between the alkyl groups and the surface; here, we demonstrate the importance of these weak interactions in a steady-state catalytic process.« less

Microwave Spectroscopic Investigations of the C-H\\cdotsπ Containing Complexes CH_2F_2\\cdotsPROPYNE and CH_2ClF\\cdotsPROPYNE

NASA Astrophysics Data System (ADS)

Peebles, Rebecca A.; Peebles, Sean A.; Christenholz, Cori L.; Ernst, Anthony A.; Dhahir, Yasser J.

2013-06-01

The spectra of the CH_2F_2\\cdotspropyne and CH_2ClF\\cdotspropyne complexes have been studied by chirped-pulse and resonant cavity Fourier-transform microwave spectroscopy and by ab initio calculations at the MP2/6-311++G(2d,2p) level. Both complexes contain C-H\\cdotsπ contacts, with the halogen atoms angled towards the methyl group end of the propyne. While CH_2F_2\\cdotspropyne has C_s symmetry, CH_2ClF\\cdotspropyne has C_1 symmetry, with the fluorine and chlorine atoms straddling the propyne. Investigation of four single ^{13}C and the DC≡CCH_3 isotopologues in CH_2F_2\\cdotspropyne has allowed a detailed structural determination, while only the ^{35}Cl and ^{37}Cl isotopologues have so far been assigned for CH_2ClF\\cdotspropyne. Experimental data will be compared with ab initio results and with the analogous acetylene complexes, both of which have C_s symmetry structures, with double C-H\\cdotsπ interactions.

Structural changes of a-CNx thin films induced by thermal annealing

NASA Astrophysics Data System (ADS)

Aziz, Siti Aisyah Abd; Awang, Rozidawati

2018-04-01

In this work, amorphous carbon nitride (a-CNx) thin films were deposited by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique at different RF powers of 60, 70, 80, 90 and 100 W for 30 min. These films were prepared using a mixture of acetylene (C2H2) at 20 sccm and nitrogen (N2) gases at 50 sccm. The films were then annealed at 400 °C in a quartz tube furnace in argon (Ar) gas. The chemical bondings of the film were analyzed by Fourier Transform Infra-red Spectroscopy (FTIR) while surface morphology and film roughness were determined by Atomic Force Microscopy (AFM). The FTIR analysis reveals that annealing resulted in the loss of C-H and C-N bonds and formation of graphitic sp2C cluster with the dissociation of N and C in the films. AFM indicates that the film surface becomes less rough which effectually enhances structural modifications and the rearrangement of the microstructure of the films after annealing.

Capillary Columns with a Sorbent Based on Functionalized Poly(1-Trimethylsilyl-1-Propyne) for the Elution Analysis of Natural Gas

NASA Astrophysics Data System (ADS)

Yakovleva, E. Yu.; Patrushev, Yu. V.; Pai, Z. P.

2018-05-01

The chromatographic properties of capillary columns prepared using functionalized poly(1- trimethylsilyl-1-propyne) (PTMSP) are evaluated and compared with the performance of a commercial column with divinylbenzene polymer sorbent. The loading capacity of a PTMSP column with dimensions of 30 m × 0.53 mm × 0.8 μm is shown to be about 2.5 times higher than that of a divinylbenzene polymer column with a diameter of 0.32 mm and a film thickness of 10 μm. The increased value of the background current for PTMSP columns at 220°C is explained by the presence of non-polar bulky substituents in the polymer chain. Differences in the order of elution are found for the following pairs of compounds: acetylene-ethylene; ethane-water; butene-1-isobutane; and sulfur dioxide-carbonyl sulfide. On a column with the functionalized PTMC, analysis of a mixture composition close to natural gas is found to be complete within 27 min.

Spray-loading: A cryogenic deposition method for diamond anvil cell

NASA Astrophysics Data System (ADS)

Scelta, Demetrio; Ceppatelli, Matteo; Ballerini, Riccardo; Hajeb, Ahmed; Peruzzini, Maurizio; Bini, Roberto

2018-05-01

An efficient loading technique has been developed for flammable, toxic, or explosive gases which can be condensed at liquid nitrogen temperature and ambient pressure in membrane diamond anvil cells (DACs). This cryogenic technique consists in a deposition of small quantities of the desired gas directly into the sample chamber. The deposition is performed using a capillary that reaches the space between the diamond anvils. The DAC is kept under inert gas overpressure during the whole process, in order to avoid contamination from atmospheric O2, CO2, and H2O. This technique provides significant advantages over standard cryo-loading and gas-loading when the condensation of dangerous samples at liquid nitrogen temperature raises safety concerns because it allows dealing with minimum quantities of condensed gases. The whole procedure is particularly fast and efficient. The "spray-loading" has been successfully used in our laboratory to load several samples including acetylene, ammonia, ethylene, and carbon dioxide/water or red phosphorus/NH3 mixtures.

A comprehensive experimental and detailed chemical kinetic modelling study of 2,5-dimethylfuran pyrolysis and oxidation

PubMed Central

Somers, Kieran P.; Simmie, John M.; Gillespie, Fiona; Conroy, Christine; Black, Gráinne; Metcalfe, Wayne K.; Battin-Leclerc, Frédérique; Dirrenberger, Patricia; Herbinet, Olivier; Glaude, Pierre-Alexandre; Dagaut, Philippe; Togbé, Casimir; Yasunaga, Kenji; Fernandes, Ravi X.; Lee, Changyoul; Tripathi, Rupali; Curran, Henry J.

2013-01-01

The pyrolytic and oxidative behaviour of the biofuel 2,5-dimethylfuran (25DMF) has been studied in a range of experimental facilities in order to investigate the relatively unexplored combustion chemistry of the title species and to provide combustor relevant experimental data. The pyrolysis of 25DMF has been re-investigated in a shock tube using the single-pulse method for mixtures of 3% 25DMF in argon, at temperatures from 1200–1350 K, pressures from 2–2.5 atm and residence times of approximately 2 ms. Ignition delay times for mixtures of 0.75% 25DMF in argon have been measured at atmospheric pressure, temperatures of 1350–1800 K at equivalence ratios (ϕ) of 0.5, 1.0 and 2.0 along with auto-ignition measurements for stoichiometric fuel in air mixtures of 25DMF at 20 and 80 bar, from 820–1210 K. This is supplemented with an oxidative speciation study of 25DMF in a jet-stirred reactor (JSR) from 770–1220 K, at 10.0 atm, residence times of 0.7 s and at ϕ = 0.5, 1.0 and 2.0. Laminar burning velocities for 25DMF-air mixtures have been measured using the heat-flux method at unburnt gas temperatures of 298 and 358 K, at atmospheric pressure from ϕ = 0.6–1.6. These laminar burning velocity measurements highlight inconsistencies in the current literature data and provide a validation target for kinetic mechanisms. A detailed chemical kinetic mechanism containing 2768 reactions and 545 species has been simultaneously developed to describe the combustion of 25DMF under the experimental conditions described above. Numerical modelling results based on the mechanism can accurately reproduce the majority of experimental data. At high temperatures, a hydrogen atom transfer reaction is found to be the dominant unimolecular decomposition pathway of 25DMF. The reactions of hydrogen atom with the fuel are also found to be important in predicting pyrolysis and ignition delay time experiments. Numerous proposals are made on the mechanism and kinetics of the previously unexplored intermediate temperature combustion pathways of 25DMF. Hydroxyl radical addition to the furan ring is highlighted as an important fuel consuming reaction, leading to the formation of methyl vinyl ketone and acetyl radical. The chemically activated recombination of HȮ2 or CH3Ȯ2 with the 5-methyl-2-furanylmethyl radical, forming a 5-methyl-2-furylmethanoxy radical and ȮH or CH3Ȯ radical is also found to exhibit significant control over ignition delay times, as well as being important reactions in the prediction of species profiles in a JSR. Kinetics for the abstraction of a hydrogen atom from the alkyl side-chain of the fuel by molecular oxygen and HȮ2 radical are found to be sensitive in the estimation of ignition delay times for fuel-air mixtures from temperatures of 820–1200 K. At intermediate temperatures, the resonantly stabilised 5-methyl-2-furanylmethyl radical is found to predominantly undergo bimolecular reactions, and as a result sub-mechanisms for 5-methyl-2-formylfuran and 5-methyl-2-ethylfuran, and their derivatives, have also been developed with consumption pathways proposed. This study is the first to attempt to simulate the combustion of these species in any detail, although future refinements are likely necessary. The current study illustrates both quantitatively and qualitatively the complex chemical behavior of what is a high potential biofuel. Whilst the current work is the most comprehensive study on the oxidation of 25DMF in the literature to date, the mechanism cannot accurately reproduce laminar burning velocity measurements over a suitable range of unburnt gas temperatures, pressures and equivalence ratios, although discrepancies in the experimental literature data are highlighted. Resolving this issue should remain a focus of future work. PMID:24273333

The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

NASA Astrophysics Data System (ADS)

Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

2017-10-01

Here, we present the latest results on the gas- and solid phase analyses in the Titan Haze Simulation (THS) experiment, developed at the NASA Ames COSmIC simulation chamber. The THS is a unique experimental platform that allows us to simulate Titan’s complex atmospheric chemistry at Titan-like temperature (200 K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma. Because of the accelerated gas flow in the expansion, the residence time of the gas in the active plasma region is less than 3 µs. This results in a truncated chemistry that enables us to control how far in the chain of chemical reactions chemistry processes[1], by adding, in the initial gas mixture, heavier molecules that have been detected as trace elements on Titan.We discuss the results of recent Mid-infrared (MIR) spectroscopy[2] and X-ray Absorption Near Edge Structure spectroscopy studies of THS Titan tholins produced in different gas mixtures (with and without acetylene and benzene). Both studies have shown the presence of nitrogen chemistry, and differences in the level and nature of the nitrogen incorporation depending on the initial gas mixture. A comparison of THS MIR spectra to VIMS data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols.In addition, a new model has been developed to simulate the plasma chemistry in the THS. Electron impact and chemical kinetics equations for more than 120 species are followed. The calculated mass spectra[3] are in good agreement with the experimental THS mass spectra[1], confirming that the short residence time in the plasma cavity limits the growth of larger species and results in a truncated chemistry, a main feature of the THS.References:[1] Sciamma-O'Brien E. et al., Icarus, 243, 325 (2014)[2] Sciamma-O'Brien E. et al., Icarus, 289, 214 (2017)[3] Raymond, A. et al., submitted

Instrument intercomparison of glyoxal, methyl glyoxal and NO2 under simulated atmospheric conditions

NASA Astrophysics Data System (ADS)

Thalman, R.; Baeza-Romero, M. T.; Ball, S. M.; Borrás, E.; Daniels, M. J. S.; Goodall, I. C. A.; Henry, S. B.; Karl, T.; Keutsch, F. N.; Kim, S.; Mak, J.; Monks, P. S.; Muñoz, A.; Orlando, J.; Peppe, S.; Rickard, A. R.; Ródenas, M.; Sánchez, P.; Seco, R.; Su, L.; Tyndall, G.; Vázquez, M.; Vera, T.; Waxman, E.; Volkamer, R.

2015-04-01

The α-dicarbonyl compounds glyoxal (CHOCHO) and methyl glyoxal (CH3C(O)CHO) are produced in the atmosphere by the oxidation of hydrocarbons and emitted directly from pyrogenic sources. Measurements of ambient concentrations inform about the rate of hydrocarbon oxidation, oxidative capacity, and secondary organic aerosol (SOA) formation. We present results from a comprehensive instrument comparison effort at two simulation chamber facilities in the US and Europe that included nine instruments, and seven different measurement techniques: broadband cavity enhanced absorption spectroscopy (BBCEAS), cavity-enhanced differential optical absorption spectroscopy (CE-DOAS), white-cell DOAS, Fourier transform infrared spectroscopy (FTIR, two separate instruments), laser-induced phosphorescence (LIP), solid-phase micro extraction (SPME), and proton transfer reaction mass spectrometry (PTR-ToF-MS, two separate instruments; for methyl glyoxal only because no significant response was observed for glyoxal). Experiments at the National Center for Atmospheric Research (NCAR) compare three independent sources of calibration as a function of temperature (293-330 K). Calibrations from absorption cross-section spectra at UV-visible and IR wavelengths are found to agree within 2% for glyoxal, and 4% for methyl glyoxal at all temperatures; further calibrations based on ion-molecule rate constant calculations agreed within 5% for methyl glyoxal at all temperatures. At the European Photoreactor (EUPHORE) all measurements are calibrated from the same UV-visible spectra (either directly or indirectly), thus minimizing potential systematic bias. We find excellent linearity under idealized conditions (pure glyoxal or methyl glyoxal, R2 > 0.96), and in complex gas mixtures characteristic of dry photochemical smog systems (o-xylene/NOx and isoprene/NOx, R2 > 0.95; R2 ∼ 0.65 for offline SPME measurements of methyl glyoxal). The correlations are more variable in humid ambient air mixtures (RH > 45%) for methyl glyoxal (0.58 < R2 < 0.68) than for glyoxal (0.79 < R2 < 0.99). The intercepts of correlations were insignificant for the most part (below the instruments' experimentally determined detection limits); slopes further varied by less than 5% for instruments that could also simultaneously measure NO2. For glyoxal and methyl glyoxal the slopes varied by less than 12 and 17% (both 3-σ) between direct absorption techniques (i.e., calibration from knowledge of the absorption cross section). We find a larger variability among in situ techniques that employ external calibration sources (75-90%, 3-σ), and/or techniques that employ offline analysis. Our intercomparison reveals existing differences in reports about precision and detection limits in the literature, and enables comparison on a common basis by observing a common air mass. Finally, we evaluate the influence of interfering species (e.g., NO2, O3 and H2O) of relevance in field and laboratory applications. Techniques now exist to conduct fast and accurate measurements of glyoxal at ambient concentrations, and methyl glyoxal under simulated conditions. However, techniques to measure methyl glyoxal at ambient concentrations remain a challenge, and would be desirable.

Instrument inter-comparison of glyoxal, methyl glyoxal and NO2 under simulated atmospheric conditions

NASA Astrophysics Data System (ADS)

Thalman, R.; Baeza-Romero, M. T.; Ball, S. M.; Borrás, E.; Daniels, M. J. S.; Goodall, I. C. A.; Henry, S. B.; Karl, T.; Keutsch, F. N.; Kim, S.; Mak, J.; Monks, P. S.; Muñoz, A.; Orlando, J.; Peppe, S.; Rickard, A. R.; Ródenas, M.; Sánchez, P.; Seco, R.; Su, L.; Tyndall, G.; Vázquez, M.; Vera, T.; Waxman, E.; Volkamer, R.

2014-08-01

The α-dicarbonyl compounds glyoxal (CHOCHO) and methyl glyoxal (CH3C(O)CHO) are produced in the atmosphere by the oxidation of hydrocarbons, and emitted directly from pyrogenic sources. Measurements of ambient concentrations inform about the rate of hydrocarbon oxidation, oxidative capacity, and secondary organic aerosol (SOA) formation. We present results from a comprehensive instrument comparison effort at 2 simulation chamber facilities in the US and Europe that included 9 instruments, and 7 different measurement techniques: Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS), Cavity Enhanced Differential Optical Absorption Spectroscopy (CE-DOAS), White-cell DOAS, Fourier Transform Infra-Red Spectroscopy (FTIR, two separate instruments), Laser Induced Phosphoresence (LIP), Solid Phase Micro Extraction (SPME), and Proton Transfer Reaction Mass Spectrometry (PTR-ToF-MS, two separate instruments; only methyl glyoxal as no significant response was observed for glyoxal). Experiments at the National Center for Atmospheric Research (NCAR) compare 3 independent sources of calibration as a function of temperature (293 K to 330 K). Calibrations from absorption cross-section spectra at UV-visible and IR wavelengths are found to agree within 2% for glyoxal, and 4% for methyl glyoxal at all temperatures; further calibrations based on ion-molecule rate constant calculations agreed within 5% for methyl glyoxal at all temperatures. At the EUropean PHOtoREactor (EUPHORE) all measurements are calibrated from the same UV-visible spectra (either directly or indirectly), thus minimizing potential systematic bias. We find excellent linearity under idealized conditions (pure glyoxal or methyl glyoxal, R2 > 0.96), and in complex gas mixtures characteristic of dry photochemical smog systems (o-xylene/NOx and isoprene/NOx, R2 > 0.95; R2 ~ 0.65 for offline SPME measurements of methyl glyoxal). The correlations are more variable in humid ambient air mixtures (RH > 45%) for methyl glyoxal (0.58 < R2 < 0.68) than for glyoxal (0.79 < R2 < 0.99). The intercepts of correlations were insignificant for the most part; slopes varied by less than 5% for instruments that also measure NO2. For glyoxal and methyl glyoxal the slopes varied by less than 12% and 17% (both 3-sigma) between inherently calibrated instruments (i.e., calibration from knowledge of the absorption cross-section). We find a larger variability among in situ techniques that employ external calibration sources (75% to 90%, 3-sigma), and/or techniques that employ offline analysis. Our inter-comparison reveal existing differences in reports about precision and detection limits in the literature, and enables comparison on a common basis by observing a common airmass. Finally, we evaluate the influence of interfering species (e.g., NO2, O3 and H2O) of relevance in field and laboratory applications. Techniques now exist to conduct fast and accurate measurements of glyoxal at ambient concentrations, and methyl glyoxal under simulated conditions. However, techniques to measure methyl glyoxal at ambient concentrations remain a challenge, and would be desirable.

Spectroscopic studies of organometallic compounds on single crystal metal surfaces: Surface acetylides of silver (110)

NASA Astrophysics Data System (ADS)

Madix, Robert J.

The nature of compounds formed by the reaction of organic molecules with metal surfaces can be studied with a battery of analytical methods based on both physicals and chemical understanding. In this paper the application of UPS, XPS, LEED and EELS as well as temperature programmed reaction spectroscopy (TPRS) and chemical titration methods to the characterization of surface complexes is discussed. Particular emphasis is given to the reaction of acetylene with a single crystal surface of silver, Ag(110). Previous work has shown that this surface, when clean, is unreactive to hydrocarbons, alcohols and carboxylic acids under ultra high vacuum conditions. Preadsorption of oxygen, however, renders the surface reactive, and a wide variety of organometallic surface compounds can be formed. As expected then, no stable adsorption state and no reaction was observed with clean Ag(110) following room temperature exposure to acetylene. Following exposure at 150 K, however, a weekly bound chemisorption state was observed to desorb at 195 K, indicating a binding energy to the surface of approximately 12 kcal/gmole. Reaction with preadsorbed oxygen gave water formulation upon dosing and produced surface intermediates which yeilded two acetylene desorption states at 195 and 175 K. Heating above 300 K to completely desorb the higher temperature state produced new, well-defined LEED Features due to residual surface carbon which disappeared when the surface was heated above 550 K. Clearly, there were distinc changes in the nature of the absorbed layer at 195, 300 and 550 K. These changes were reflected in XPS. For the weakly chemisorbed acetylene a large C(ls) peak at 285.6 eV with a small, broad, indistinc shoulder at higher binding energy (288.2) was observed. The spectrum of the species following acetylene desorption at 275 K, however, showed the formulation of a large C(ls) peak at 283.6 eV in addition to peaks characteristics of the weakly chemisorbed state. This result indicated that the carbon atoms in the surface acetylide became inequivalent. Heating to 300 K produced a single peak at 282.8 eV which reverted to 283.4 when heated above 550 K; the carbon atoms became chemically equivalent. This latter state could be removed completely by O 2 to form CO 2(3). The XPS results showed quantitative conversion of all surface carbon from each state observed. Conclusive evidence regarding the identity of these states was obtained with titration experiments with deuterated acetic acid. CH 3COOD was adsorbed on top of the acetylenic residues at 150 K and heated to note the isotopes of acetylene that desorbed. The 275 K acetylene desorption peak, which showed inequivalent carbon atoms, was titrated by CH 3COOD to form C 2HD, indicating C 2H as the stable surface species. The species formed above 300 K, which showed equivalent carbon atoms in XPS, titrated to form C 2D 2, indicating a C 2 surface species. In each case the formulation of surface acetate was quantitative. The structure of these species was probed further with high resolution electron energy loss spectroscopy. The weakly chemisorbed molecular state exhibited vibrational losses at 300, 700 and 3270 cm -1, characteristics of an acetylene-surface stretching motion, a C-C-H bend and the C-H stretch respectively. No C-C stretch was observed, indicating that the molecule lay parallel to the plane of the surface. For adsorbed C 2H, bands were observed at 300, 690 and 3250cm -1. The high C-H stretching frequency indicated that the C-C bound order was near three. The absence of a C-C stretch in the spectrum was somewhat surprising, but was explained by a σ-π bonded complex in which the -C=CH species was flattened toward the surface by an interaction of an Ag atom with the π system of the acetylide.

Vapor-liquid equilibria for 1,1-difluoroethane + acetylene and 1,1-difluoroethane + 1,1-dichloroethane at 303.2 K and 323.2 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, J.S.; Lee, Y.W.; Kim, J.D.

1996-09-01

Isothermal vapor-liquid equilibria for 1,1-difluoroethane (HFC-152a) + acetylene and 1,1-difluoroethane + 1,1-dichloroethane (HCC-150a) were measured in a circulation type apparatus at 303.2 K and 323.2 K. The experimental data were correlated with the Peng-Robinson equation of state using the Wong and Sandler mixing rule, and the relevant parameters are presented.

Method for the preparation of novel polyacetylene-type polymers

DOEpatents

Zeigler, John M.

1989-01-01

Polymerization of acetylenic monomers is achieved by using a catalyst which is the reaction product of a tungsten compound and a reducing agent effective to reduce W(VI) to W(III) and/or IV), e.g., WCl.sub.6.(organo-Li, organo-Mg or polysilane). The resultant silylated polymers are of heretofore unachievable high molecular weight and can be used as precursors to a wide variety of new acetylenic polymers by application of substitution reactions.

Excited-state dynamics of acetylene excited to individual rotational level of the V04K01 subband

NASA Astrophysics Data System (ADS)

Makarov, Vladimir I.; Kochubei, Sergei A.; Khmelinskii, Igor V.

2006-01-01

Dynamics of the IR emission induced by excitation of the acetylene molecule using the (32Ka0,1,2,ÃAu1←41la1,X˜Σg+1) transition was investigated. The observed IR emission was assigned to transitions between the ground-state vibrational levels. Acetylene fluorescence quenching induced by external electric and magnetic fields acting upon the system prepared using the (34Ka1,ÃAu1←00la0,X˜Σg+1) excitation was also studied. External electric field creates an additional radiationless pathway to the ground-state levels, coupling levels of the ÃAu1 excited state to the quasiresonant levels of the X˜Σg+1 ground state. The level density of the ground state in the vicinity of the excited state is very high, thus the electric-field-induced transition is irreversible, with the rate constant described by the Fermi rule. Magnetic field alters the decay profile without changing the fluorescence quantum yield in collisionless conditions. IR emission from the CCH transient was detected, and was also affected by the external electric and magnetic fields. Acetylene predissociation was demonstrated to proceed by the direct S1→S0 mechanism. The results were explained using the previously developed theoretical approach, yielding values of the relevant model parameters.

Structure and Function of the Unusual Tungsten Enzymes Acetylene Hydratase and Class II Benzoyl-Coenzyme A Reductase.

PubMed

Boll, Matthias; Einsle, Oliver; Ermler, Ulrich; Kroneck, Peter M H; Ullmann, G Matthias

2016-01-01

In biology, tungsten (W) is exclusively found in microbial enzymes bound to a bis-pyranopterin cofactor (bis-WPT). Previously known W enzymes catalyze redox oxo/hydroxyl transfer reactions by directly coordinating their substrates or products to the metal. They comprise the W-containing formate/formylmethanofuran dehydrogenases belonging to the dimethyl sulfoxide reductase (DMSOR) family and the aldehyde:ferredoxin oxidoreductase (AOR) families, which form a separate enzyme family within the Mo/W enzymes. In the last decade, initial insights into the structure and function of two unprecedented W enzymes were obtained: the acetaldehyde forming acetylene hydratase (ACH) belongs to the DMSOR and the class II benzoyl-coenzyme A (CoA) reductase (BCR) to the AOR family. The latter catalyzes the reductive dearomatization of benzoyl-CoA to a cyclic diene. Both are key enzymes in the degradation of acetylene (ACH) or aromatic compounds (BCR) in strictly anaerobic bacteria. They are unusual in either catalyzing a nonredox reaction (ACH) or a redox reaction without coordinating the substrate or product to the metal (BCR). In organic chemical synthesis, analogous reactions require totally nonphysiological conditions depending on Hg2+ (acetylene hydration) or alkali metals (benzene ring reduction). The structural insights obtained pave the way for biological or biomimetic approaches to basic reactions in organic chemistry. © 2016 S. Karger AG, Basel.

Carboxymethyl chitosan/conducting polymer as water-soluble composite binder for LiFePO4 cathode in lithium ion batteries

NASA Astrophysics Data System (ADS)

Zhong, Haoxiang; He, Aiqin; Lu, Jidian; Sun, Minghao; He, Jiarong; Zhang, Lingzhi

2016-12-01

A water-soluble conductive composite binder consisting of carboxymethyl chitosan (CCTS) as a binder and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a conduction-promoting agent is reported for the LiFePO4 (LFP) cathode in Li-ion batteries. The introduction of conductive PEDOT:PSS as a conductive composite binder facilitates the formation of homogeneous and continuous conducting bridges throughout the electrode and raises the compaction density of the electrode sheet by decreasing the amounts of the commonly used conducting agent of acetylene black. The optimized replacement ratios of acetylene black with PEDOT:PSS (acetylene black/PEDOT:PSS = 1:1, by weight) are obtained by measuring electrical conductivity, peel strength and compaction density of the electrode sheets. The LFP half-cell with the optimized conductive binder exhibits better cycling and rate performance and more favorable electrochemical kinetics than that using only acetylene black conducting agent. The pilot application of PEDOT:PSS/CCTS binder in 10 Ah CCTS-LFP prismatic cell exhibits a comparable cycling performance, retaining 89.7% of capacity at 1 C/2 C (charge/discharge) rate as compared with 90% for commercial PVDF-LFP over 1000 cycles, and better rate capability than that of commercial PVDF-LFP, retaining 98% capacity of 1 C at 7 C rate as compared with 95.4% for PVDF-LFP.

Pulsed-induced electromagnetically induced transparency in the acetylene-filled hollow-core fibers

NASA Astrophysics Data System (ADS)

Rodríguez, Nayeli Casillas; Stepanov, Serguei; Miramontes, Manuel Ocegueda; Hernández, Eliseo Hernández

2017-06-01

Experimental results on pulsed excitation of electromagnetically induced transparency (EIT) in the acetylene-filled hollow-core photonic crystal fiber (HC-PCF) at pressures 0.1-0.4 Torr are reported. The EIT was observed both in Λ and V interaction configurations with the continuous probe wave tuned to R9 (1520.08 nm) acetylene absorption line and with the control pulses tuned to P11 (1531.58 nm) and P9 (1530.37 nm) lines, respectively. The utilized control pulses were of up to 40 ns duration with <2.5 ns fronts and with maximum input power 1 W. The maximum modulation depth of the initial probe wave absorption via EIT was up to 40 and 15% for the co- and counter-propagation of the probe and control waves, respectively, and importance of the waves polarization matching was demonstrated. For a qualitative explanation of reduction in the counter-propagation EIT efficiency a simple model of the accelerated mismatch of the two-frequency EIT resonance with deviation of the molecule thermal velocity from the resonance value was utilized. It was shown experimentally that the EIT efficiencies in both configurations do not depend on the longitudinal velocity of the molecules. The characteristic relaxation time of the of the EIT response was found to be about 9 ns, i.e., is close to the relaxation times T 1,2 of the acetylene molecules under the utilized experimental conditions.

Growth of ammonia-oxidizing archaea in soil microcosms is inhibited by acetylene.

PubMed

Offre, Pierre; Prosser, James I; Nicol, Graeme W

2009-10-01

Autotrophic ammonia-oxidizing bacteria were considered to be responsible for the majority of ammonia oxidation in soil until the recent discovery of the autotrophic ammonia-oxidizing archaea. To assess the relative contributions of bacterial and archaeal ammonia oxidizers to soil ammonia oxidation, their growth was analysed during active nitrification in soil microcosms incubated for 30 days at 30 degrees C, and the effect of an inhibitor of ammonia oxidation (acetylene) on their growth and soil nitrification kinetics was determined. Denaturing gradient gel electrophoresis (DGGE) analysis of bacterial ammonia oxidizer 16S rRNA genes did not detect any change in their community composition during incubation, and quantitative PCR (qPCR) analysis of bacterial amoA genes indicated a small decrease in abundance in control and acetylene-containing microcosms. DGGE fingerprints of archaeal amoA and 16S rRNA genes demonstrated changes in the relative abundance of specific crenarchaeal phylotypes during active nitrification. Growth was also indicated by increases in crenarchaeal amoA gene copy number, determined by qPCR. In microcosms containing acetylene, nitrification and growth of the crenarchaeal phylotypes were suppressed, suggesting that these crenarchaea are ammonia oxidizers. Growth of only archaeal but not bacterial ammonia oxidizers occurred in microcosms with active nitrification, indicating that ammonia oxidation was mostly due to archaea in the conditions of the present study.

Glass fibers and vapor phase components of cigarette smoke as cofactors in experimental respiratory tract carcinogenesis.

PubMed

Feron, V J; Kuper, C F; Spit, B J; Reuzel, P G; Woutersen, R A

1985-01-01

Syrian golden hamsters were given intratracheal instillations of glass fibers with or without BP suspended in saline, once a fortnight for 52 weeks; the experiment was terminated at week 85. No tumors of the respiratory tract were observed in hamsters treated with glass fibers alone. There was no indication that glass fibers enhanced the development of respiratory tract tumors induced by BP. In another study Syrian golden hamsters were exposed to fresh air or to a mixture of 4 major vapor phase components of cigarette smoke, viz. isoprene (800----700 ppm), methyl chloride (1000----900 ppm), methyl nitrite (200----190 ppm) and acetaldehyde (1400----1200 ppm) for a period of at most 23 months. Some of the animals were also given repeated intratracheal instillations of BP or norharman in saline. Laryngeal tumors were found in 7/31 male and 6/32 female hamsters exposed only to the vapor mixture, whereas no laryngeal tumors occurred in controls. The tumor response of the larynx most probably has to be ascribed entirely to the action of acetaldehyde. Simultaneous treatment with norharman or BP did not affect the tumor response of the larynx. Acetaldehyde may occur in the vapor phase of cigarette smoke at levels up to 2000 ppm. Chronic inhalation exposure of rats to acetaldehyde at levels of 0 (controls), 750, 1500 or 3000----1000 ppm resulted in a high incidence of nasal carcinomas, both squamous cell carcinomas of the respiratory epithelium and adenocarcinomas of the olfactory epithelium. It was discussed that acetaldehyde may significantly contribute to the induction of bronchogenic cancer by cigarette smoke in man. No evidence was obtained for a role of isoprene, methyl chloride or methyl nitrite in the induction of lung cancer by cigarette smoke.

H3K4me1 marks DNA regions hypomethylated during aging in human stem and differentiated cells

PubMed Central

Fernández, Agustín F.; Bayón, Gustavo F.; Urdinguio, Rocío G.; Toraño, Estela G.; García, María G.; Carella, Antonella; Petrus-Reurer, Sandra; Ferrero, Cecilia; Martinez-Camblor, Pablo; Cubillo, Isabel; García-Castro, Javier; Delgado-Calle, Jesús; Pérez-Campo, Flor M.; Riancho, José A.; Bueno, Clara; Menéndez, Pablo; Mentink, Anouk; Mareschi, Katia; Claire, Fabian; Fagnani, Corrado; Medda, Emanuela; Toccaceli, Virgilia; Brescianini, Sonia; Moran, Sebastián; Esteller, Manel; Stolzing, Alexandra; de Boer, Jan; Nisticò, Lorenza; Stazi, Maria A.

2015-01-01

In differentiated cells, aging is associated with hypermethylation of DNA regions enriched in repressive histone post-translational modifications. However, the chromatin marks associated with changes in DNA methylation in adult stem cells during lifetime are still largely unknown. Here, DNA methylation profiling of mesenchymal stem cells (MSCs) obtained from individuals aged 2 to 92 yr identified 18,735 hypermethylated and 45,407 hypomethylated CpG sites associated with aging. As in differentiated cells, hypermethylated sequences were enriched in chromatin repressive marks. Most importantly, hypomethylated CpG sites were strongly enriched in the active chromatin mark H3K4me1 in stem and differentiated cells, suggesting this is a cell type–independent chromatin signature of DNA hypomethylation during aging. Analysis of scedasticity showed that interindividual variability of DNA methylation increased during aging in MSCs and differentiated cells, providing a new avenue for the identification of DNA methylation changes over time. DNA methylation profiling of genetically identical individuals showed that both the tendency of DNA methylation changes and scedasticity depended on nongenetic as well as genetic factors. Our results indicate that the dynamics of DNA methylation during aging depend on a complex mixture of factors that include the DNA sequence, cell type, and chromatin context involved and that, depending on the locus, the changes can be modulated by genetic and/or external factors. PMID:25271306

Liquid-liquid equilibria for 2,3-butanediol + water + organic solvents at 303. 15 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, S.; Pandya, G.; Chakrabarti, T.

1994-10-01

2, 3-Butanediol, an important industrial chemical, is of interest because of its application as a solvent and liquid fuel additive. Liquid-liquid equilibria at 303.15 [+-] 0.5 K were measured for water + 2, 3-butanediol + butan-1-ol, + 3-methyl-1-butanol, + 4-methyl-2-pentanone, + tributyl phosphate, and + butyl acetate. Complete phase diagrams were obtained by evaluating the solubility and tie-line results for each ternary mixture. The consistency of the tie-line results was ascertained using an Othmer-Tobias plot. The distribution coefficient and separation factors were evaluated over the immiscibility region. Among the solvents studied, butan-1-ol is the most effective one though tributyl phosphatemore » and 3-methyl-1-butanol may be preferred because of their low solubility and high selectivity.« less

Synthesis of β-Peptide Standards for Use in Model Prebiotic Reactions

NASA Astrophysics Data System (ADS)

Forsythe, Jay G.; English, Sloane L.; Simoneaux, Rachel E.; Weber, Arthur L.

2018-05-01

A one-pot method was developed for the preparation of a series of β-alanine standards of moderate size (2 to ≥12 residues) for studies concerning the prebiotic origins of peptides. The one-pot synthesis involved two sequential reactions: (1) dry-down self-condensation of β-alanine methyl ester, yielding β-alanine peptide methyl ester oligomers, and (2) subsequent hydrolysis of β-alanine peptide methyl ester oligomers, producing a series of β-alanine peptide standards. These standards were then spiked into a model prebiotic product mixture to confirm by HPLC the formation of β-alanine peptides under plausible reaction conditions. The simplicity of this approach suggests it can be used to prepare a variety of β-peptide standards for investigating differences between α- and β-peptides in the context of prebiotic chemistry.

CpG island methylation profile in non-invasive oral rinse samples is predictive of oral and pharyngeal carcinoma.

PubMed

Langevin, Scott M; Eliot, Melissa; Butler, Rondi A; Cheong, Agnes; Zhang, Xiang; McClean, Michael D; Koestler, Devin C; Kelsey, Karl T

2015-01-01

There are currently no screening tests in routine use for oral and pharyngeal cancer beyond visual inspection and palpation, which are provided on an opportunistic basis, indicating a need for development of novel methods for early detection, particularly in high-risk populations. We sought to address this need through comprehensive interrogation of CpG island methylation in oral rinse samples. We used the Infinium HumanMethylation450 BeadArray to interrogate DNA methylation in oral rinse samples collected from 154 patients with incident oral or pharyngeal carcinoma prior to treatment and 72 cancer-free control subjects. Subjects were randomly allocated to either a training or a testing set. For each subject, average methylation was calculated for each CpG island represented on the array. We applied a semi-supervised recursively partitioned mixture model to the CpG island methylation data to identify a classifier for prediction of case status in the training set. We then applied the resultant classifier to the testing set for validation and to assess the predictive accuracy. We identified a methylation classifier comprised of 22 CpG islands, which predicted oral and pharyngeal carcinoma with a high degree of accuracy (AUC = 0.92, 95 % CI 0.86, 0.98). This novel methylation panel is a strong predictor of oral and pharyngeal carcinoma case status in oral rinse samples and may have utility in early detection and post-treatment follow-up.

Methylation of arsenic by recombinant human wild-type arsenic (+ 3 oxidation state) methyltransferase and its methionine 287 threonine (M287T) polymorph: Role of glutathione

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Lan; Saunders, R. Jesse; Drobná, Zuzana

2012-10-01

Arsenic (+ 3 oxidation state) methyltransferase (AS3MT) is the key enzyme in the pathway for methylation of arsenicals. A common polymorphism in the AS3MT gene that replaces a threonyl residue in position 287 with a methionyl residue (AS3MT/M287T) occurs at a frequency of about 10% among populations worldwide. Here, we compared catalytic properties of recombinant human wild-type (wt) AS3MT and AS3MT/M287T in reaction mixtures containing S-adenosylmethionine, arsenite (iAs{sup III}) or methylarsonous acid (MAs{sup III}) as substrates and endogenous or synthetic reductants, including glutathione (GSH), a thioredoxin reductase (TR)/thioredoxin (Trx)/NADPH reducing system, or tris (2-carboxyethyl) phosphine hydrochloride (TCEP). With either TR/Trx/NADPHmore » or TCEP, wtAS3MT or AS3MT/M287T catalyzed conversion of iAs{sup III} to MAs{sup III}, methylarsonic acid (MAs{sup V}), dimethylarsinous acid (DMAs{sup III}), and dimethylarsinic acid (DMAs{sup V}); MAs{sup III} was converted to DMAs{sup III} and DMAs{sup V}. Although neither enzyme required GSH to support methylation of iAs{sup III} or MAs{sup III}, addition of 1 mM GSH decreased K{sub m} and increased V{sub max} estimates for either substrate in reaction mixtures containing TR/Trx/NADPH. Without GSH, V{sub max} and K{sub m} values were significantly lower for AS3MT/M287T than for wtAS3MT. In the presence of 1 mM GSH, significantly more DMAs{sup III} was produced from iAs{sup III} in reactions catalyzed by the M287T variant than in wtAS3MT-catalyzed reactions. Thus, 1 mM GSH modulates AS3MT activity, increasing both methylation rates and yield of DMAs{sup III}. AS3MT genotype exemplified by differences in regulation of wtAS3MT and AS3MT/M287T-catalyzed reactions by GSH may contribute to differences in the phenotype for arsenic methylation and, ultimately, to differences in the disease susceptibility in individuals chronically exposed to inorganic arsenic. -- Highlights: ► Human AS3MT and AS3MT(M287T) require a dithiol reductant for optimal activity. ► Both enzymes methylate arsenite to tri- and pentavalent methylated metabolites. ► Neither enzyme requires glutathione (GSH) to methylate arsenite or methylarsonite. ► However, in presence of a dithiol addition of 1 mM GSH increases methylation rates. ► In presence of 1 mM GSH, AS3MT(M287T) produces more dimethylarsinite than AS3MT.« less

Phase-transition oscillations induced by a strongly focused laser beam

NASA Astrophysics Data System (ADS)

Devailly, Clémence; Crauste-Thibierge, Caroline; Petrosyan, Artyom; Ciliberto, Sergio

2015-11-01

We report the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture when this is enlightened by a strongly focused infrared laser beam. The mixture is poly-methyl-meth-acrylate (PMMA)-3-octanone, which has an upper critical solution temperature at Tc=306.6 K and volume fraction ϕc=12.8 % [Crauste et al., arXiv:1310.6720, 2013]. We describe the dynamical properties of the oscillations, which are produced by a competition between various effects: the local accumulation of PMMA produced by the laser beam, thermophoresis, and nonlinear diffusion. We show that the main properties of this kind of oscillations can be reproduced in the Landau theory for a binary mixture in which a local driving mechanism, simulating the laser beam, is introduced.

Transient quantum coherent effects in the acetylene-filled hollow-core photonic crystal fiber

NASA Astrophysics Data System (ADS)

Stepanov, S.; Rodríguez Casillas, N.; Ocegueda Miramontes, M.; Hernández Hernández, E.

2017-02-01

Low-pressure acetylene in the hollow-core photonic crystal structure fibers is an excellent medium for the room-temperature investigation of the coherent quantum effects in communication wavelength region. Pulsed excitation enables observation of new coherent phenomena like optical nutation or photon echo and evaluation of important temporal characteristics of the light-molecule interactions. We also report original experimental results on the pulsed excitation of the electromagnetically induced transparency in co- and counter-propagation configurations.

Navy-ASEE (American Society for Engineering Education) Summer Faculty Research Program for 1983 with a Summary of Statistics and a Cumulative Compilation of Data on Later Research Fallouts from the First Five Years of the Program, 1979-1983.

DTIC Science & Technology

1983-01-01

POLYMER FORMATION VIA NUCLEOPHILIC ADDITION TO ACETYLENES Carl L. Bumgardner Department of Chemistry North Carolina...State University Raleigh, North Carolina ABSTRACT Utilizing the ability of acetylenes to add nucleophiles, two new polymer - forming reactions were...examined. The first involved hydroquinone and 1, 4-diethynylbenzene, which, under base calatysis, gave a new semiconducting polymer having the

Design and Processing of Structural Composite Batteries

DTIC Science & Technology

2007-09-01

The woven fabric, e is 72wt% LiFePO4 , 8wt% acetylene lack, and 20wt% poly(ethylene oxide) 200k as a binder. Acetylene black ensures electrical will...2.1.3 Cathode The composite cathode material utilizes LiFePO4 chemistry. The composition of the cathode material film deposited onto the metal substrat... LiFePO4 chemistry (over a 2.8-4.0V range (8)) including stainless steel and titanium. Stainless steel was evaluated in this udy due to its high

Soluble silylated polyacetylene derivatives and their use as percursors to novel polyacetylene-type polymers

DOEpatents

Zeigler, John M.

1989-01-01

Polymerization of acetylenic monomers is achieved by using a catalyst which is the reaction product of a tungsten compound and a reducing agent effective to reduce W(VI) to W(III and/or IV), e.g., WCl.sub.6.(organo-Li, organo-Mg or polysilane). The resultant silylated polymers are of heretofore unachievable high molecular weight and can be used as precursors to a wide variety of new acetylenic polymers by application of substitution reactions.

Method for the preparation of novel polyacetylene-type polymers

DOEpatents

Zeigler, J.M.

1987-11-09

Polymerization of acetylenic monomers is achieved by using a catalyst which is the reaction product of a tungsten compound and a reducing agent effective to reduce W(VI) to W(III and/or IV), e.g., WCl/sub 6//center dot/(organo-Li, organo-Mg or polysilane). The resultant silylated polymers are of heretofore unachievable high molecular weight and can be used as precursors to a wide variety of new acetylenic polymers by application of substitution reactions. 1 tab.