WorldWideScience

Sample records for atmospheric reaction products

  1. Studies of the Atmospheric Chemsitry of Energy-Related Volatile Organic Compounds and of their Atmospheric Reaction Products

    Energy Technology Data Exchange (ETDEWEB)

    Roger Atkinson; Janet Arey

    2007-04-14

    The focus of this contract was to investigate selected aspects of the atmospheric chemistry of volatile organic compounds (VOCs) emitted into the atmosphere from energy-related sources as well as from biogenic sources. The classes of VOCs studied were polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs, the biogenic VOCs isoprene, 2-methyl-3-buten-2-ol and cis-3-hexen-1-ol, alkenes (including alkenes emitted from vegetation) and their oxygenated atmospheric reaction products, and a series of oxygenated carbonyl and hydroxycarbonyl compounds formed as atmospheric reaction products of aromatic hydrocarbons and other VOCs. Large volume reaction chambers were used to investigate the kinetics and/or products of photolysis and of the gas-phase reactions of these organic compounds with hydroxyl (OH) radicals, nitrate (NO3) radicals, and ozone (O3), using an array of analytical instrumentation to analyze the reactants and products (including gas chromatography, in situ Fourier transform infrared spectroscopy, and direct air sampling atmospheric pressure ionization tandem mass spectrometry). The following studies were carried out. The photolysis rates of 1- and 2-nitronaphthalene and of eleven isomeric methylnitronaphthalenes were measured indoors using blacklamp irradiation and outdoors using natural sunlight. Rate constants were measured for the gas-phase reactions of OH radicals, Cl atoms and NO3 radicals with naphthalene, 1- and 2-methylnaphthalene, 1- and 2-ethylnaphthalene and the ten dimethylnaphthalene isomers. Rate constants were measured for the gas-phase reactions of OH radicals with four unsaturated carbonyls and with a series of hydroxyaldehydes formed as atmospheric reaction products of other VOCs, and for the gas-phase reactions of O3 with a series of cycloalkenes. Products of the gas-phase reactions of OH radicals and O3 with a series of biogenically emitted VOCs were identified and quantified. Ambient atmospheric measurements of the concentrations of a

  2. Pressure Effects on Product Channels of Hydrocarbon Radical-Radical Reactions; Implications for Modelling of Planetary Atmospheres

    Science.gov (United States)

    Fahr, A.; Halpern, J.; N'doumi, M.

    2011-10-01

    Previously we had studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modelling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2 and allyl, H2CCCH3) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. We have experimentally determined pressuredependent product yields for self- and cross-radical reactions performed at 298 K and at selected pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final products were determined by gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the observations and provided valuable information on complex reaction mechanisms. These studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report a compilation of our earlier results relevant to planetary atmospheres in addition to recent ones for allyl radical (H2CCCH3) reactions.

  3. Reaction products and mechanisms for the reaction of n-butyl vinyl ether with the oxidants OH and Cl: Atmospheric implications

    Science.gov (United States)

    Colmenar, Inmaculada; Martín, Pilar; Cabañas, Beatriz; Salgado, Sagrario; Tapia, Araceli; Martínez, Ernesto

    2015-12-01

    A reaction product study for the degradation of butyl vinyl ether (CH3(CH2)3OCHdbnd CH2) by reaction with chlorine atoms (Cl) and hydroxyl radicals (OH) has been carried out using Fourier Transform Infrared absorption spectroscopy (FTIR) and/or Gas Chromatography-Mass Spectrometry with a Time of Flight analyzer (GC-TOFMS). The rate coefficient for the reaction of butyl vinyl ether (BVE) with chlorine atoms has also been evaluated for the first time at room temperature (298 ± 2) K and atmospheric pressure (708 ± 8) Torr. The rate coefficient obtained was (9.9 ± 1.5) × 10-10 cm3 molecule-1 s-1 and this indicates the high reactivity of butyl vinyl ether with Cl atoms. However, this value may be affected by the dark reaction of BVE with Cl2. The results of a qualitative study of the Cl reaction show that the main oxidation products are butyl formate (CH3(CH2)3OC(O)H), butyl chloroacetate (CH3(CH2)3OC(O)CH2Cl and formyl chloride (HCOCl). Individual yields in the ranges ∼16-40% and 30-70% in the absence and presence of NOx, respectively, have been estimated for these products. In the OH reaction, butyl formate and formic acid were identified as the main products, with yields of around 50 and 20%, respectively. Based on the results of this work and a literature survey, the addition of OH radicals and Cl atoms at the terminal C atom of the double bond in CH3(CH2)3OCHdbnd CH2 has been proposed as the first step in the reaction mechanism for both of the studied oxidants. The tropospheric lifetime of butyl vinyl ether is very short and, as a consequence, it will be rapidly degraded and will only be involved in tropospheric chemistry at a local level. The degradation products of these reactions should be considered when evaluating the atmospheric impact.

  4. The molecular dynamics of atmospheric reaction

    Science.gov (United States)

    Polanyi, J. C.

    1971-01-01

    Detailed information about the chemistry of the upper atmosphere took the form of quantitative data concerning the rate of reaction into specified states of product vibration, rotation and translation for exothermic reaction, as well as concerning the rate of reaction from specified states of reagent vibration, rotation and translation for endothermic reaction. The techniques used were variants on the infrared chemiluminescence method. Emphasis was placed on reactions that formed, and that removed, vibrationally-excited hydroxyl radicals. Fundamental studies were also performed on exothermic reactions involving hydrogen halides.

  5. The oleic acid-ozone heterogeneous reaction system: products, kinetics, secondary chemistry, and atmospheric implications of a model system – a review

    Directory of Open Access Journals (Sweden)

    J. Zahardis

    2006-11-01

    Full Text Available The heterogeneous processing of organic aerosols by trace oxidants has many implications to atmospheric chemistry and climate regulation. This review covers a model heterogeneous reaction system (HRS: the oleic acid-ozone HRS and other reaction systems featuring fatty acids, and their derivatives. The analysis of the primary products of ozonolysis (azelaic acid, nonanoic acid, 9-oxononanoic acid, nonanal is described. Anomalies in the relative product yields are noted and explained by the observation of secondary chemical reactions. The secondary reaction products arising from reactive Criegee intermediates are mainly peroxidic, notably secondary ozonides and α-acyloxyalkyl hydroperoxide polymers. These highly oxygenated products are of low volatility and hydrophilic which may enhance the ability of particles to act as cloud condensation nuclei. The kinetic description of this HRS is critically reviewed. Most kinetic studies suggest this oxidative processing is either a near surface reaction that is limited by the diffusion of ozone or a surface based reaction. Internally mixed particles and coatings represent the next stage in the progression towards more realistic proxies of tropospheric organic aerosols and a description of the products and the kinetics resulting from the ozonolysis of these proxies, which are based on fatty acids or their derivatives, is presented. Finally, a series of atmospheric implications of oxidative processing of particulate containing fatty acids is presented. These implications include the extended lifetime of unsaturated species in the troposphere facilitated by the presence of solids, semisolids or viscous phases, and an enhanced rate of ozone uptake by particulate unsaturates compared to corresponding gas phase organics. Ozonolysis of oleic acid enhances its CCN activity, which implies that oxidatively processed particulate may contribute to indirect forcing of radiation. Other effects, including the potential

  6. Meson production in + reactions

    Indian Academy of Sciences (India)

    H Machner; M Betigeri; J Bojowald; A Budzanowski; A Chatterjee; J Ernst; L Freindl; D Frekers; W Garske; K Grewer; A Hamacher; J Ilieva; L Jarczyk; K Kilian; S Kliczewski; W Klimala; D Kolev; T Kutsarova; J Lieb; H Machner; A Magiera; H Nann; L Pentchev; H S Plendl; D Protić; B Razen; P Von Rossen; B J Roy; R Siudak; J Smyrski; R V Srikantiah; A Strzałkowski; R Tsenov; K Zwoll

    2001-08-01

    Total and differential cross sections for the reactions $p+d → 3He + 0 with = ; and + → 3H + + were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward–backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied.

  7. LSM-YSZ Reactions in Different Atmospheres

    DEFF Research Database (Denmark)

    Chen, Ming; Liu, Yi-Lin; Hagen, Anke;

    2009-01-01

    The influences of the oxygen partial pressure and the LSM/YSZ ratio on the LSM-YSZ interface reactions at 1,000 °C were investigated. Both pellets and diffusion couples were employed in the study. The equilibrium thermodynamics of the LSM-YSZ reactions was clarified based on the pellet study......-powder reaction. LSM reacts differently with YSZ in different atmospheres. In air, m-ZrO2 (monoclinic) is formed; while in N2, SrZrO3 and/or La2Zr2O7 are formed depending on the initial LSM/YSZ ratio. The reactions are reversible with varying P(O2) i.e. treating the sample in air after the heat treatment in N2...... results in a decomposition of the formed La- and Sr-zirconates. The de-stabilisation of the LSM-YSZ interface under long-term annealing at 1,000 °C originates mainly from the inter-diffusion across the interface. Under reduced P(O2), the Mn diffusion from LSM into YSZ is enhanced. High P(O2) (0.21 atm...

  8. Reaction product imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, D.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  9. Atmospheric chemistry of CF3CHCH2 and C4F9CHCH2: Products of the gas-phase reactions with Cl atoms and OH radicals

    DEFF Research Database (Denmark)

    Nakayama, T.; Takahashi, K.; Matsumi, Y.;

    2007-01-01

    +/- 5% and 6.2 +/- 0.5 respectively. Reaction with Cl atoms proceeds via addition to the > CC Reaction with O-2 and decomposition via C-C bond scission...... presence of NOx gives CxF2x+1CHO in a yield of 88 +/- 9 Reaction with OH radicals proceeds via addition to the > CC atmospheric fate of CF3CHClCH2O radicals is reaction with O-2 to give CF3CHClCHO. The OH radical initiated oxidation of CxF2x+1CHCH2 (x = 1 and 4) in 700 Torr of air in the...

  10. Crossed molecular beam studies of atmospheric chemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingsong

    1993-04-01

    The dynamics of several elementary chemical reactions that are important in atmospheric chemistry are investigated. The reactive scattering of ground state chlorine or bromine atoms with ozone molecules and ground state chlorine atoms with nitrogen dioxide molecules is studied using a crossed molecular beams apparatus with a rotatable mass spectrometer detector. The Cl + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at four collision energies ranging from 6 kcal/mole to 32 kcal/mole. The derived product center-of-mass angular and translational energy distributions show that the reaction has a direct reaction mechanism and that there is a strong repulsion on the exit channel. The ClO product is sideways and forward scattered with respect to the Cl atom, and the translational energy release is large. The Cl atom is most likely to attack the terminal oxygen atom of the ozone molecule. The Br + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at five collision energies ranging from 5 kcal/mole to 26 kcal/mole. The derived product center-of-mass angular and translational energy distributions are quite similar to those in the Cl + O{sub 3} reaction. The Br + O{sub 3} reaction has a direct reaction mechanism similar to that of the Cl + O{sub 3} reaction. The electronic structure of the ozone molecule seems to play the central role in determining the reaction mechanism in atomic radical reactions with the ozone molecule. The Cl + NO{sub 2} {yields} ClO + NO reaction has been studied at three collision energies ranging from 10.6 kcal/mole to 22.4 kcal/mole. The center-of-mass angular distribution has some forward-backward symmetry, and the product translational energy release is quite large. The reaction proceeds through a short-lived complex whose lifetime is less than one rotational period. The experimental results seem to show that the Cl atom mainly attacks the oxygen atom instead of the nitrogen atom of the NO{sub 2} molecule.

  11. Atmospheric science and power production

    Energy Technology Data Exchange (ETDEWEB)

    Randerson, D. (ed.)

    1984-07-01

    This is the third in a series of scientific publications sponsored by the US Atomic Energy Commission and the two later organizations, the US Energy Research and Development Adminstration, and the US Department of Energy. The first book, Meteorology and Atomic Energy, was published in 1955; the second, in 1968. The present volume is designed to update and to expand upon many of the important concepts presented previously. However, the present edition draws heavily on recent contributions made by atmospheric science to the analysis of air quality and on results originating from research conducted and completed in the 1970s. Special emphasis is placed on how atmospheric science can contribute to solving problems relating to the fate of combustion products released into the atmosphere. The framework of this book is built around the concept of air-quality modeling. Fundamentals are addressed first to equip the reader with basic background information and to focus on available meteorological instrumentation and to emphasize the importance of data management procedures. Atmospheric physics and field experiments are described in detail to provide an overview of atmospheric boundary layer processes, of how air flows around obstacles, and of the mechanism of plume rise. Atmospheric chemistry and removal processes are also detailed to provide fundamental knowledge on how gases and particulate matter can be transformed while in the atmosphere and how they can be removed from the atmosphere. The book closes with a review of how air-quality models are being applied to solve a wide variety of problems. Separate analytics have been prepared for each chapter.

  12. CRITICAL REVIEW OF N, N{sup +}, N{sup +} {sub 2}, N{sup ++}, And N{sup ++} {sub 2} MAIN PRODUCTION PROCESSES AND REACTIONS OF RELEVANCE TO TITAN'S ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Dutuit, Odile; Thissen, Roland; Vuitton, Veronique [Institut de Planetologie et d' Astrophysique de Grenoble, UJF-Grenoble 1/CNRS-INSU, UMR 5274, F-38041 Grenoble (France); Carrasco, Nathalie [Laboratoire Atmospheres, Milieux, Observations Spatiales, CNRS, UVSQ/UPMC, F-78280 Guyancourt (France); Alcaraz, Christian; Pernot, Pascal [Laboratoire de Chimie Physique, CNRS/UPS UMR 8000, Bat.349, F-91405 Orsay Cedex (France); Balucani, Nadia; Casavecchia, Piergiorgio [Dipartimento di Chimica, Universita degli Studi di Perugia, Via Elce di Sotto, 8, I-06123 Perugia (Italy); Canosa, Andre; Picard, Sebastien Le [Departement de Physique Moleculaire, Universite de Rennes 1, Institut de Physique de Rennes, UMR 6251 CNRS Universite, Campus de Beaulieu-Bat 11C, F-35042 Rennes Cedex (France); Loison, Jean-Christophe [Institut des Sciences Moleculaires, Universite Bordeaux 1/CNRS, UMR 5255, 351 cours de la Liberation, F-33405 Talence Cedex (France); Herman, Zdenek; Zabka, Jan [J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3 CZ-182 23 Prague 8 (Czech Republic); Ascenzi, Daniela; Tosi, Paolo [Dipartimento di Fisica, Universita di Trento, Via Sommarive 14, I-38123 Trento (Italy); Franceschi, Pietro [Biostatistics and Data Management, IASMA Research and Innovation Centre, Fondazione E. Mach, Via E. Mach, 1 I-38010 S. Michele all' Adige (Italy); Price, Stephen D. [Department of Chemistry, UCL, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Lavvas, Panayotis, E-mail: roland.thissen@obs.ujf-grenoble.fr [Groupe de Spectrometrie Moleculaire et Atmospherique, CNRS, UMR 6089, Campus Moulin de la Housse-BP 1039, Universite Reims Champagne-Ardenne, F-51687 Reims (France)

    2013-02-15

    This paper is a detailed critical review of the production processes and reactions of N, N{sup +}, N{sup +} {sub 2}, N{sup ++}, and N{sup ++} {sub 2} of relevance to Titan's atmosphere. The review includes neutral, ion-molecule, and recombination reactions. The review covers all possible active nitrogen species under Titan's atmospheric conditions, specifically N{sub 2} (A {sup 3}{Sigma}{sup +} {sub u}), N ({sup 4} S), N ({sup 2} D), N ({sup 2} P), N{sup +} {sub 2}, N{sup +} ({sup 3} P), N{sup +} ({sup 1} D), N{sup ++} {sub 2}, and N{sup ++} species, and includes a critical survey of the reactions of N, N{sup +}, N{sup +} {sub 2}, N{sup ++}, and N{sup ++} {sub 2} with N{sub 2}, H{sub 2}, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8} and the deuterated hydrocarbon analogs, as well as the recombination reactions of N{sup +} {sub 2}, N{sup +}, N{sup ++} {sub 2}, and N{sup ++}. Production processes, lifetimes, and quenching by collisions with N{sub 2} of all reactant species are reviewed. The N ({sup 4} S) state is reactive with radicals and its reactions with CH{sub 2}, CH{sub 3}, C{sub 2}H{sub 3}, and C{sub 2}H{sub 5} are reviewed. Metastable states N{sub 2} (A {sup 3}{Sigma}{sup +} {sub u}), N ({sup 2} D), and N ({sup 2} P) are either reactive or quenched by collisions with the target molecules reviewed. The reactions of N{sup +} ({sup 1} D) have similar rate constants as N{sup +} ({sup 3} P), but the product branching ratios differ significantly. Temperature effects and the role of the kinetic energy content of reactants are investigated. In all cases, experimental uncertainties of laboratory data are reported or estimated. Recommended values with uncertainties, or estimated values when no data are available, are given for rate constants and product branching ratios at 300 K and at the atmospheric temperature range of Titan (150-200 K for neutral reactions and 150 K for ion reactions).

  13. Positron production within our atmosphere

    Science.gov (United States)

    Dwyer, Joseph

    2016-04-01

    Positrons are commonly produced within our atmosphere by cosmic rays and the decay radioactive isotopes. Energetic positrons are also produced by pair production from the gamma rays generated by relativistic runaway electrons. Indeed, such positrons have been detected in Terrestrial Electron Beams (TEBs) in the inner magnetosphere by Fermi/GBM. In addition, positrons play an important role in relativistic feedback discharges (also known as dark lightning). Relativistic feedback models suggest that these discharges may be responsible for Terrestrial Gamma-ray Flashes (TGFs) and some gamma-ray glows. When producing TGFs, relativistic feedback discharges may generate large, lightning-like currents with current moments reaching hundreds of kA-km. In addition, relativistic feedback discharges also may limit the electric field that is possible in our atmosphere, affecting other mechanisms for generating runaway electrons. It is interesting that positrons, often thought of as exotic particles, may play an important role in thunderstorm processes. In this presentation, the role of positrons in high-energy atmospheric physics will be discussed. The unusual observation of positron clouds inside a thunderstorm by the ADELE instrument on an NCAR/NSF Gulfstream V aircraft will also be described. These observations illustrate that we still have much to learn about positron production within our atmosphere.

  14. Possible atmospheric lifetimes and chemical reaction mechanisms for selected HCFCs, HFCs, CH3CCl3, and their degradation products against dissolution and/or degradation in seawater and cloudwater

    Science.gov (United States)

    Wine, P. H.; Chameides, W. L.

    1990-01-01

    For a wide variety of atmospheric species including CO2, HNO3, and SO2, dissolution in seawater or cloudwater followed by hydrolysis or chemical reaction represents a primary pathway for removal from the atmosphere. In order to determine if this mechanism can also remove significant amounts of atmospheric chlorofluorocarbons (HCFC's), fluorocarbons (HFC's), and their degradation products, an investigation was undertaken as part of the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS). In this investigation, the rates at which CHCl2CF3 (HCFC-123), CCl2FCH3 (HCFC-141b), CClF2CH3 (HCFC-142b), CHClF2 (HCFC-22), CHClFCF3 (HCFC-124) CH2FCF3 (HFC-134a) CHF2CH3 (HFC-152a), CHF2CF3 (HFC-125), and CH3CCl3 can be dissolved in the oceans and in cloudwater were estimated from the species' thermodynamic and chemical properties using simple mathematical formulations to simulate the transfer of gases from the atmosphere to the ocean or cloudwater. The ability of cloudwater and rainwater to remove gas phase degradation products of these compounds was also considered as was the aqueous phase chemistry of the degradation products. The results of this investigation are described.

  15. A Computational Study of Acid Catalyzed Aerosol Reactions of Atmospherically Relevant Epoxides

    Science.gov (United States)

    Epoxides are important intermediates of atmospheric isoprene oxidation. Their subsequent reactions in the particle phase lead to the production of organic compounds detected in ambient aerosols. We apply density functional theory to determine the important kinetic factors that ...

  16. Pion production reaction near threshold

    International Nuclear Information System (INIS)

    The differential cross section of the 40Ca(p,π+)41Ca reaction has been measured. The energy dependence of pion production near threshold has been studied at constant transferred momentum. The cross-section decreases by a factor 7, for proton energies varying from 154 to 149MeV (E(π) varies from 17.4 to 12.4MeV). The results are analyzed in the framework of the one nucleon mechanism

  17. Atmospheric Pressure Microwave Assisted Heterogeneous Catalytic Reactions

    Directory of Open Access Journals (Sweden)

    Farid Chemat

    2007-07-01

    Full Text Available The purpose of the study was to investigate microwave selective heatingphenomena and their impact on heterogeneous chemical reactions. We also present a toolwhich will help microwave chemists to answer to such questions as “My reaction yields90% after 7 days at reflux; is it possible to obtain the same yield after a few minutes undermicrowaves?” and to have an approximation of their reactions when conducted undermicrowaves with different heterogeneous procedures. This model predicting reactionkinetics and yields under microwave heating is based on the Arrhenius equation, inagreement with experimental data and procedures.

  18. Atmospheric oxidation of 1,3-butadiene: characterization of gas and aerosol reaction products and implications for PM2.5

    Science.gov (United States)

    Jaoui, M.; Lewandowski, M.; Docherty, K.; Offenberg, J. H.; Kleindienst, T. E.

    2014-12-01

    Secondary organic aerosol (SOA) was generated by irradiating 1,3-butadiene (13BD) in the presence of H2O2 or NOx. Experiments were conducted in a smog chamber operated in either flow or batch mode. A filter/denuder sampling system was used for simultaneously collecting gas- and particle-phase products. The chemical composition of the gas phase and SOA was analyzed using derivative-based methods (BSTFA, BSTFA + PFBHA, or DNPH) followed by gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography (HPLC) analysis of the derivative compounds. The analysis showed the occurrence of more than 60 oxygenated organic compounds in the gas and particle phases, of which 31 organic monomers were tentatively identified. The major identified products include glyceric acid, d-threitol, erythritol, d-threonic acid, meso-threonic acid, erythrose, malic acid, tartaric acid, and carbonyls including glycolaldehyde, glyoxal, acrolein, malonaldehyde, glyceraldehyde, and peroxyacryloyl nitrate (APAN). Some of these were detected in ambient PM2.5 samples, and could potentially serve as organic markers of 13BD. Furthermore, a series of oligoesters were detected and found to be produced through chemical reactions occurring in the aerosol phase between compounds bearing alcoholic groups and compounds bearing acidic groups. SOA was analyzed for organic mass to organic carbon (OM /OC) ratio, effective enthalpy of vaporization (Δ Hvapeff), and aerosol yield. The average OM /OC ratio and SOA density were 2.7 ± 0.09 and 1.2 ± 0.05, respectively. The average Δ Hvapeff was -26.08 ± 1.46 kJ mol-1, a value lower than that of isoprene SOA. The average laboratory SOA yield measured in this study at aerosol mass concentrations between 22.5 and 140.2 μg m-3 was 0.025 ± 0.011, a value consistent with the literature (0.021-0.178). While the focus of this study has been examination of the particle-phase measurements, the gas-phase photooxidation products have also been

  19. Heterogeneous reactions of volatile organic compounds in the atmosphere

    Science.gov (United States)

    Shen, Xiaoli; Zhao, Yue; Chen, Zhongming; Huang, Dao

    2013-04-01

    Volatile organic compounds (VOCs) are of central importance in the atmosphere because of their close relation to air quality and climate change. As a significant sink for VOCs, the fate of VOCs via heterogeneous reactions may explain the big gap between field and model studies. These reactions play as yet unclear but potentially crucial role in atmospheric processes. In order to better evaluate this reaction pathway, we present the first specific review for the progress of heterogeneous reaction studies on VOCs, including carbonyl compounds, organic acids, alcohols, and so on. Our review focuses on the processes for heterogeneous reactions of VOCs under varying experimental conditions, as well as their implications for trace gas and HOx budget, secondary organic aerosol (SOA) formation, physicochemical properties of aerosols, and human health. Finally, we propose the future direction for laboratory studies of heterogeneous chemistry of VOCs that should be carried out under more atmospherically relevant conditions, with a special emphasis on the effects of relative humidity and illumination, the multicomponent reaction systems, and reactivity of aged and authentic particles. In particular, more reliable uptake coefficients, based on the abundant elaborate laboratory studies, appropriate calibration, and logical choice criterion, are urgently required in atmospheric models.

  20. 10Be production calculations in the atmosphere

    International Nuclear Information System (INIS)

    Cosmic rays (CRs) interacting with the Earth's atmosphere produce a cascade of secondary particles and cosmogenic nuclides. Cosmogenic nuclides itself are stored in natural archives such as ice cores and can therefore be measured by e.g. accelerator mass spectrometry (AMS). Here we present our calculations of the cosmogenic radionuclide 10Be, which is produced by spallation reactions between secondary neutrons and protons and the atmospheric gases nitrogen and oxygen, using PLANETOCOSMICS, a GEANT4 based computer code (Desorgher[2006]).

  1. Fission product transport in the atmosphere

    International Nuclear Information System (INIS)

    In the present thesis,a theoretical treatment has been developed for investigating the fission product transport in the atmosphere, and expressing its underlying dynamics. Some basic material has been critically reviewed for the purpose of establishing the mathematical equations that govern the motion of a general pollutant - whether it is radioactive or not - in the atmosphere. Such review included the study of particulate matter motion in the atmosphere and radioactive cloud motion, together with the analysis of available mathematical models for atmospheric dispersion

  2. Atmospheric degradation of 3-methylfuran: kinetic and products study

    Directory of Open Access Journals (Sweden)

    A. Tapia

    2010-10-01

    Full Text Available A study of the kinetics and products obtained from the reactions of 3-methylfuran with the main atmospheric oxidants has been performed. The rate coefficients for the gas-phase reaction of 3-methylfuran with OH and NO3 radicals have been determined at room temperature and atmospheric pressure (air and N2 as bath gases, using a relative method with different experimental techniques. The absolute rate coefficients obtained for these reactions were (in units cm3 molecule−1 s−1: kOH=(1.13±0.22×10−10 and kNO3=(1.26±0.18×10−11. These rate coefficients have been compared with those available in the literature. The products from the reaction of 3-methylfuran with OH, NO3 and Cl atoms in the absence and in the presence of NOx species have also been determined. The main reaction products obtained were chlorinated methylfuranones and hydroxy-methylfuranones for the reaction of 3-methylfuran with Cl atoms, 2-methylbutenedial, 3-methyl-2,5-furanodione and hydroxy-methylfuranones for the reaction of 3-methylfuran with OH and NO3 radicals and also nitrated compounds for the reaction with NO3 radicals. The results indicate that in all cases the main reaction path is the addition to the double bond of the aromatic ring followed by ring opening in the case of OH and NO3 radicals. The formation of 3-furaldehyde and hydroxy-methylfuranones (in the reactions of 3-methylfuran with Cl atoms and NO3 radicals confirmed the H-atom abstraction from the methyl group and from the aromatic ring, respectively. This study represents the first product determination for both Cl atoms and the NO3 radical in reactions with 3-methylfuran. The reaction mechanisms and atmospheric implications of the reactions under consideration are also discussed.

  3. Reaction Kinetics of Meteoric Sodium Reservoirs in the Upper Atmosphere.

    Science.gov (United States)

    Gómez Martín, J C; Garraway, S A; Plane, J M C

    2016-03-10

    The gas-phase reactions of a selection of sodium-containing species with atmospheric constituents, relevant to the chemistry of meteor-ablated Na in the upper atmosphere, were studied in a fast flow tube using multiphoton ionization time-of-flight mass spectrometry. For the first time, unambiguous observations of NaO and NaOH in the gas phase under atmospheric conditions have been achieved. This enabled the direct measurement of the rate constants for the reactions of NaO with H2, H2O, and CO, and of NaOH with CO2, which at 300-310 K were found to be (at 2σ confidence level): k(NaO + H2O) = (2.4 ± 0.6) × 10(-10) cm(3) molecule (-1) s(-1), k(NaO + H2) = (4.9 ± 1.2) × 10(-12) cm(3) molecule (-1) s(-1), k(NaO + CO) = (9 ± 4) × 10(-11) cm(3) molecule (-1) s(-1), and k(NaOH + CO2 + M) = (7.6 ± 1.6) × 10(-29) cm(6) molecule (-2) s(-1) (P = 1-4 Torr). The NaO + H2 reaction was found to make NaOH with a branching ratio ≥ 99%. A combination of quantum chemistry and statistical rate theory calculations are used to interpret the reaction kinetics and extrapolate the atmospherically relevant experimental results to mesospheric temperatures and pressures. The NaO + H2O and NaOH + CO2 reactions act sequentially to provide the major atmospheric sink of meteoric Na and therefore have a significant impact on the underside of the Na layer in the terrestrial mesosphere: the newly determined rate constants shift the modeled peak to about 93 km, i.e., 2 km higher than observed by ground-based lidars. This highlights further uncertainties in the Na chemistry cycle such as the unknown rate constant of the NaOH + H reaction. The fast Na-recycling reaction between NaO and CO and a re-evaluated rate constant of the NaO + CO2 sink should be now considered in chemical models of the Martian Na layer. PMID:25723735

  4. Atmospheric production rate of {sup 36}Cl

    Energy Technology Data Exchange (ETDEWEB)

    Parrat, Y.; Hajdas, W.; Baltensperger, U.; Synal, H.A.; Kubik, P.W.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Using experimental cross sections, a new calculation of the atmospheric production rate of {sup 36}Cl was carried out. A mean production rate of 20 atoms m{sup -2}s{sup -1} was obtained, which is lower than mean {sup 36}Cl deposition rates. (author) 2 figs., 7 refs.

  5. Carbon compounds in the atmosphere and their chemical reactions

    OpenAIRE

    Martišová, Petra

    2013-01-01

    The essay dissert on compounds of carbon in the atmosphere and its reaction. The most important are carbon dioxide, carbon monoxide and methane. Included among important compounds of carbon are volatile organic substances, polycyclic aromatic hydrocarbon and dioxin. Carbon dioxide and methane representing greenhouse gases have also indispensable meaning. As they, together with water vapour, nitrogen monoxide and other gases are causing the major part of greenhouse effect. Primarily because of...

  6. Insights into secondary reactions occurring during atmospheric ablation of micrometeoroids

    Science.gov (United States)

    Court, Richard W.; Tan, Jonathan

    2016-05-01

    Ablation of micrometeoroids during atmospheric entry yields volatile gases such as water, carbon dioxide, and sulfur dioxide, capable of altering atmospheric chemistry and hence the climate and habitability of the planetary surface. While laboratory experiments have revealed the yields of these gases during laboratory simulations of ablation, the reactions responsible for the generation of these gases have remained unclear, with a typical assumption being that species simply undergo thermal decomposition without engaging in more complex chemistry. Here, pyrolysis-Fourier transform infrared spectroscopy reveals that mixtures of meteorite-relevant materials undergo secondary reactions during simulated ablation, with organic matter capable of taking part in carbothermic reduction of iron oxides and sulfates, resulting in yields of volatile gases that differ from those predicted by simple thermal decomposition. Sulfates are most susceptible to carbothermic reduction, producing greater yields of sulfur dioxide and carbon dioxide at lower temperatures than would be expected from simple thermal decomposition, even when mixed with meteoritically relevant abundances of low-reactivity Type IV kerogen. Iron oxides were less susceptible, with elevated yields of water, carbon dioxide, and carbon monoxide only occurring when mixed with high abundances of more reactive Type III kerogen. We use these insights to reinterpret previous ablation simulation experiments and to predict the reactions capable of occurring during ablation of carbonaceous micrometeoroids in atmospheres of different compositions.

  7. Novel Haloperoxidase Reaction: Synthesis of Dihalogenated Products

    OpenAIRE

    Geigert, John; Neidleman, Saul L.; Dalietos, Demetrios J.; DeWitt, Susanne K.

    1983-01-01

    The enzymatic synthesis of vicinal, dihalogenated products from alkenes and alkynes is described. The enzymatic reaction required an alkene or alkyne, dilute hydrogen peroxide, a haloperoxidase, and molar amounts of halide ions. Vicinal dichloro, dibromo, and diiodo products could be formed. A hydroxyl group on the carbon adjacent to the carbon-carbon double or triple bond lowered the halide ion concentration needed to produce the dihalo product. This reaction offers one explanation for the o...

  8. Atmospheric Production of Perchlorate on Earth and Mars

    Science.gov (United States)

    Claire, M.; Catling, D. C.; Zahnle, K. J.

    2009-12-01

    Natural production and preservation of perchlorate on Earth occurs only in arid environments. Isotopic evidence suggests a strong role for atmospheric oxidation of chlorine species via pathways including ozone or its photochemical derivatives. As the Martian atmosphere is both oxidizing and drier than the driest places on Earth, we propose an atmospheric origin for the Martian perchlorates measured by NASA's Phoenix Lander. A variety of hypothetical formation pathways can be proposed including atmospheric photochemical reactions, electrostatic discharge, and gas-solid reactions. Here, we investigate gas phase formation pathways using a 1-D photochemical model (Catling et al. 2009, accepted by JGR). Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we start with a study of the means to produce Atacama perchlorate. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. These results are sensitive to estimated reaction rates for ClO3 species. The feasibility of gas phase production for the Atacama provides justification for further investigations of gas phase photochemistry as a possible source for Martian perchlorate. In addition to the Atacama results, we will present a preliminary study incorporating chlorine chemistry into an existing Martian photochemical model (Zahnle et al. JGR 2008).

  9. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxi...

  10. Snake antivenoms: adverse reactions and production technology

    Directory of Open Access Journals (Sweden)

    VM Morais

    2009-01-01

    Full Text Available Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animals. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism as: anaphylactic reactions mediated by IgE, anaphylactoid reactions caused by complement system activation, and pyrogenic reactions produced mainly by the presence of endotoxins in the final product. In the future, antivenoms may be replaced by humanized antibodies, specific neutralizing compounds or vaccination. Meanwhile, improvements in antivenom quality will be focused on the obtainment of a more purified and specific product in compliance with good manufacturing practices and at an affordable cost.

  11. Atmospheric Reactions of a Series of Hexenols with OH Radical and Ozone

    Science.gov (United States)

    Gai, Yanbo; Lin, Xiaoxiao; Ma, Qiao; Yang, Chengqiang; Zhao, Weixiong; Zhang, Weijun

    2016-04-01

    C6 hexenols are one of the most significant groups of biogenic volatile organic compounds (BVOCs). Because of their antibacterial properties, C6 hexenols can be emitted by a wide number of plants in response to changes in the ambient environment. The oxidation of these compounds in the atmosphere is involved in the formation of tropospheric ozone and secondary organic aerosols (SOA), thus causing significant effects on atmospheric chemistry and the climate. The lack of corresponding kinetic parameters and product information of their oxidation reactions will result in incomplete atmospheric chemical mechanisms and models. In this paper, we will overview our recent research progress on the study of the atmospheric reactions of a series of C6 hexenols with OH radicals and ozone. A series of studies were conducted using both experimental and theoretical methods. Corresponding rate constants were obtained, and reaction mechanisms were also analyzed. It could be concluded that both the nature of the substituent and its position play a fundamental role in the reactivity of the C6 hexenols toward OH radicals and O3. An activating effect of the -OH group in OH radical reactions was found, thus making the H-abstraction channel non-negligible in reactions of these unsaturated alcohols with OH radicals. The removal of these C6 hexenols by ozone also showed great importance and could be competitive with the major recognized sinks by OH radicals. These studies are of great significance for understanding the mechanism of atmospheric chemical reactions of hexenols and improving the atmospheric chemistry model. Experimental detail and corresponding results will be presented. Acknowledgements. This work was supported by the National Natural Science Foundation of China (21307137, 41575125 and 91544228), and the Natural Science Foundation of Anhui Province (1508085J03).

  12. Secondary aerosol formation from atmospheric reactions of aliphatic amines

    Directory of Open Access Journals (Sweden)

    S. M. Murphy

    2007-01-01

    Full Text Available Although aliphatic amines have been detected in both urban and rural atmospheric aerosols, little is known about the chemistry leading to particle formation or the potential aerosol yields from reactions of gas-phase amines. We present here the first systematic study of aerosol formation from the atmospheric reactions of amines. Based on laboratory chamber experiments and theoretical calculations, we evaluate aerosol formation from reaction of OH, ozone, and nitric acid with trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and ethanolamine. Entropies of formation for alkylammonium nitrate salts are estimated by molecular dynamics calculations enabling us to estimate equilibrium constants for the reactions of amines with nitric acid. Though subject to significant uncertainty, the calculated dissociation equilibrium constant for diethylammonium nitrate is found to be sufficiently small to allow for its atmospheric formation, even in the presence of ammonia which competes for available nitric acid. Experimental chamber studies indicate that the dissociation equilibrium constant for triethylammonium nitrate is of the same order of magnitude as that for ammonium nitrate. All amines studied form aerosol when photooxidized in the presence of NOx with the majority of the aerosol mass present at the peak of aerosol growth consisting of aminium (R3NH+ nitrate salts, which repartition back to the gas phase as the parent amine is consumed. Only the two tertiary amines studied, trimethylamine and triethylamine, are found to form significant non-salt organic aerosol when oxidized by OH or ozone; calculated organic mass yields for the experiments conducted are similar for ozonolysis (15% and 5% respectively and photooxidation (23% and 8% respectively. The non-salt organic aerosol formed appears to be more stable than the nitrate salts and does not quickly repartition back to the gas phase.

  13. Charged lepton production from iron induced by atmospheric neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Sajjad Athar, M.; Ahmad, S.; Singh, S.K. [Aligarh Muslim University, Department of Physics, Aligarh (India)

    2005-06-01

    The charged current lepton production induced by neutrinos in {sup 56}Fe nuclei has been studied. The calculations have been done for the quasielastic as well as the inelastic reactions assuming {delta}-dominance and take into account the effect of Pauli blocking, Fermi motion and the renormalization of weak transition strengths in the nuclear medium. The quasielastic production cross-sections for lepton production are found to be strongly reduced due to nuclear effects, while there is about 10% reduction in the inelastic cross-sections in the absence of the final-state interactions of the pions. The numerical results for the momentum and angular distributions of the leptons averaged over the various atmospheric-neutrino spectra at the Soudan and Gran Sasso sites have been presented. The effect of nuclear-model dependence and the atmospheric-flux dependence on the relative yield of {mu} to ehas been studied and discussed. (orig.)

  14. Chemical Characterization and Reactivity of Fuel-Oxidizer Reaction Product

    Science.gov (United States)

    David, Dennis D.; Dee, Louis A.; Beeson, Harold D.

    1997-01-01

    Fuel-oxidizer reaction product (FORP), the product of incomplete reaction of monomethylhydrazine and nitrogen tetroxide propellants prepared under laboratory conditions and from firings of Shuttle Reaction Control System thrusters, has been characterized by chemical and thermal analysis. The composition of FORP is variable but falls within a limited range of compositions that depend on three factors: the fuel-oxidizer ratio at the time of formation; whether the composition of the post-formation atmosphere is reducing or oxidizing; and the reaction or post-reaction temperature. A typical composition contains methylhydrazinium nitrate, ammonium nitrate, methylammonium nitrate, and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. Thermal decomposition reactions of the FORP compositions used in this study were unremarkable. Neither the various compositions of FORP, the pure major components of FORP, nor mixtures of FORP with propellant system corrosion products showed any unusual thermal activity when decomposed under laboratory conditions. Off-limit thruster operations were simulated by rapid mixing of liquid monomethylhydrazine and liquid nitrogen tetroxide in a confined space. These tests demonstrated that monomethylhydrazine, methylhydrazinium nitrate, ammonium nitrate, or Inconel corrosion products can induce a mixture of monomethylhydrazine and nitrogen tetroxide to produce component-damaging energies. Damaging events required FORP or metal salts to be present at the initial mixing of monomethylhydrazine and nitrogen tetroxide.

  15. Metal catalyzed atmospheric oxidation reactions. A challenge to coordination chemists

    Energy Technology Data Exchange (ETDEWEB)

    Coichev, N. (Sao Paulo Univ., SP (Brazil). Inst. de Quimica); Van Eldik, R. (Universitaet Witten/Herdecke (Germany))

    1994-01-01

    Oxidation reactions of SO[sub x] and NO[sub y] species in the aqueous phase can play an important role in atmospheric chemistry and are of major environmental concern. The auto-oxidation processes are known to be catalyzed by trace metal ions and complexes. An overview of the most important reactions in metal catalyzed autoxidation processes is presented. Attention is given to the oxidation of the SO[sub x] and NO[sub y] species separately, as well as to the combined chemistry that results from the interaction of SO[sub x] and NO[sub y] species in the absence and presence of metal ions. Our work has revealed a fascinating redox cycling of the metal ions and complexes during such autoxidation processes, which has turned out to present quite a challenge to coordination chemists. (authors). 118 refs., 4 figs., 1 tab.

  16. Kinetic and mechanistic study of the atmospheric reaction of MBO331 with Cl atoms

    Science.gov (United States)

    Rodríguez, Diana; Rodríguez, Ana; Garzón, Andrés; Granadino-Roldán, José M.; Soto, Amparo; Aranda, Alfonso; Notario, Alberto

    2012-12-01

    The present work deals with the reaction of 3-methyl-3-buten-1-ol (MBO331) with Cl atoms, which has been investigated by gas chromatography with flame ionization detection (GC-FID) at atmospheric pressure in N2 or air, using the relative rate technique. The rate constant reaction at 298 ± 1 K was found to be (5.01 ± 0.70) × 10-10 cm3 molecule-1 s-1, using cyclohexane, octane and 1-butene as a reference compounds. The temperature dependence for the reaction was studied within the 298-333 K range. Additionally, a product identification under atmospheric conditions has been performed for the first time by GC-MS, with 3-methyl-3-butenal, methacrolein and chloroacetone being observed as degradation products. A theoretical study on the reaction at the QCISD(T)/6-311G**//MP2/6-311G** level was also carried out to obtain more information on the mechanism. From the theoretical study it can be predicted that Cl addition to the double bond proceeds through lower energy barriers than H-abstraction pathways and therefore is energetically favoured. Finally, atmospheric implications of the results obtained are discussed.

  17. Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

    Science.gov (United States)

    Garland, Rebecca M.; Elrod, Matthew J.; Kincaid, Kristi; Beaver, Melinda R.; Jimenez, Jose L.; Tolbert, Margaret A.

    While it is well established that organics compose a large fraction of the atmospheric aerosol mass, the mechanisms through which organics are incorporated into atmospheric aerosols are not well understood. Acid-catalyzed reactions of compounds with carbonyl groups have recently been suggested as important pathways for transfer of volatile organics into acidic aerosols. In the present study, we use the aerodyne aerosol mass spectrometer (AMS) to probe the uptake of gas-phase hexanal into ammonium sulfate and sulfuric acid aerosols. While both deliquesced and dry non-acidic ammonium sulfate aerosols showed no organic uptake, the acidic aerosols took up substantial amounts of organic material when exposed to hexanal vapor. Further, we used 1H-NMR, Fourier transform infrared (FTIR) spectroscopy and GC-MS to identify the products of the acid-catalyzed reaction of hexanal in acidic aerosols. Both aldol condensation and hemiacetal products were identified, with the dominant reaction products dependent upon the initial acid concentration of the aerosol. The aldol condensation product was formed only at initial concentrations of 75-96 wt% sulfuric acid in water. The hemiacetal was produced at all sulfuric acid concentrations studied, 30-96 wt% sulfuric acid in water. Aerosols up to 88.4 wt% organic/11.1 wt% H 2SO 4/0.5 wt% water were produced via these two dimerization reaction pathways. The UV-VIS spectrum of the isolated aldol condensation product, 2-butyl 2-octenal, extends into the visible region, suggesting these reactions may impact aerosol optical properties as well as aerosol composition. In contrast to previous suggestions, no polymerization of hexanal or its products was observed at any sulfuric acid concentration studied, from 30 to 96 wt% in water.

  18. Snake antivenoms: adverse reactions and production technology

    OpenAIRE

    VM Morais; H Massaldi

    2009-01-01

    Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animals. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism ...

  19. Reactions analysis of di-pions production

    International Nuclear Information System (INIS)

    After a discussion of ambiguities in the methods used to obtain informations on the ππ diffusion from the reaction π-p→π+π-n with unpolarized targets, a model-independent method is proposed to determine experimentally the cross section for the S-wave production in the reaction π+p→π+π-Δ++. Comparing the S-wave di-pion production in the ζ-mass region from the recent experimental results on the reactions π+p→π=π-Δ++ and π-p→π-π+n on a polarized target, it is found that the amount of S-wave production is generally consistent with the lower bound obtained from the di-pion decay moments

  20. High energy photons production in nuclear reactions

    International Nuclear Information System (INIS)

    Hard photon production, in nucleus-nucleus collisions, were studied at beam energies between 10 and 125 MeV. The main characteristics of the photon emission are deduced. They suggest that the neutron-proton collisions in the early stage of the reaction are the main source of high energy gamma-rays. An overview of the theoretical approaches is given and compared with experimental results. Theoretical attempts to include the contribution of charged pion exchange currents to photon production, in calculations of proton-nucleus-gamma and nucleus-nucleus-gamma reactions, showed suitable fitting with experimental data

  1. Fractionation of Stable Isotopes in Atmospheric Aerosol Reactions

    DEFF Research Database (Denmark)

    Meusinger, Carl

    Aerosols - particles suspended in air - are the single largest uncertainty in our current understanding of Earth's climate. They also affect human health, infrastructure and ecosystems. Aerosols are emitted either directly into the atmosphere or are formed there for instance in response to chemical...... reactions and undergo complex chemical and physical changes during their lifetimes. In order to assess processes that form and alter aerosols, information provided by stable isotopes can be used to help constrain estimates on the strength of aerosol sources and sinks. This thesis studies (mass......-independent) fractionation processes of stable isotopes of C, N, O and S in order to investigate three different systems related to aerosols: 1. Post-depositional processes of nitrate in snow that obscure nitrate ice core records 2. Formation and aging of secondary organic aerosol generated by ozonolysis of X...

  2. Fusion reaction product diagnostics in ASDEX

    International Nuclear Information System (INIS)

    A diagnostic method was developed to look for the charged fusion products from the D(D,p)T-reactions in the divertor tokamak ASDEX. With a semi-conductor detector it was possible to evaluate the ion temperature in thermal plasmas from the proton energy spectra as well as from the triton spectra. In lower-hybrid wave heated plasmas non-thermal (fast) ions were observed. These ions create fusion products with a characteristically different energy spectrum. (orig.)

  3. The O+ + CO2 reaction: New results and atmospheric implications

    International Nuclear Information System (INIS)

    The vibrational distribution of the O2+ product ion in the reaction of O+ with CO2 has been measured in a selected ion flow tube using the monitor ion technique. At 300 K the measured vibrational distribution is 45% of the ions in v = 1, 32% in v ≥ 2 and 23% in v = 0. However, it is possible that vibrational quenching by the monitor gas may affect the distribution, and the nascent population may be entirely in v > O. The branching ratio between the O2+ + CO and the CO2+ + O product channels has been measured as a function of ion drift velocity. The implications of these experiments for terrestrial releases of CO2 into the ionosphere and for the ionospheres of Mars and Venus are considered

  4. Ion-ion reactions for charge reduction of biopolymer at atmospheric pressure ambient

    Institute of Scientific and Technical Information of China (English)

    Yue Ming Zhou; Jian Hua Ding; Xie Zhang; Huan Wen Chen

    2007-01-01

    Extractive electrospray ionization source (EESI) was adapted for ion-ion reaction, which was demonstrated by using a linear quadrupole ion trap mass spectrometer for the first ion-ion reaction of biopolymers in the atmospheric pressure ambient.

  5. Neutrinos from charm production in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Enberg, Rikard [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden)

    2014-11-18

    Atmospheric neutrinos are produced in interactions of cosmic rays with Earth's atmosphere. At very high energy, the contribution from semi-leptonic decays of charmed hadrons, known as the prompt neutrino flux, dominates over the conventional flux from pion and kaon decays. This is due to the very short lifetime of the charmed hadrons, which therefore do not lose energy before they decay. The calculation of this process is difficult because the Bjorken-x at which the parton distribution functions are evaluated is very small. This is a region where QCD is not well understood, and large logarithms must be resummed. Available parton distribution functions are not known at such small x and extrapolations must be made. Theoretically, the fast rise of the structure functions for small x ultimately leads to parton saturation. This contribution describes the 'ERS' [1] calculation of the prompt neutrino flux, which includes parton saturation effects in the QCD production cross section of charm quarks. The ERS flux calculation is used by e.g. the IceCube collaboration as a standard benchmark background. We are now updating this calculation to take into account the recent LHC data on the charm cross section, as well as recent theoretical developments in QCD. Some of the issues involved in this calculation are described.

  6. Charge Exchange Reaction in Dopant-Assisted Atmospheric Pressure Chemical Ionization and Atmospheric Pressure Photoionization

    Science.gov (United States)

    Vaikkinen, Anu; Kauppila, Tiina J.; Kostiainen, Risto

    2016-04-01

    The efficiencies of charge exchange reaction in dopant-assisted atmospheric pressure chemical ionization (DA-APCI) and dopant-assisted atmospheric pressure photoionization (DA-APPI) mass spectrometry (MS) were compared by flow injection analysis. Fourteen individual compounds and a commercial mixture of 16 polycyclic aromatic hydrocarbons were chosen as model analytes to cover a wide range of polarities, gas-phase ionization energies, and proton affinities. Chlorobenzene was used as the dopant, and methanol/water (80/20) as the solvent. In both techniques, analytes formed the same ions (radical cations, protonated molecules, and/or fragments). However, in DA-APCI, the relative efficiency of charge exchange versus proton transfer was lower than in DA-APPI. This is suggested to be because in DA-APCI both dopant and solvent clusters can be ionized, and the formed reagent ions can react with the analytes via competing charge exchange and proton transfer reactions. In DA-APPI, on the other hand, the main reagents are dopant-derived radical cations, which favor ionization of analytes via charge exchange. The efficiency of charge exchange in both DA-APPI and DA-APCI was shown to depend heavily on the solvent flow rate, with best efficiency seen at lowest flow rates studied (0.05 and 0.1 mL/min). Both DA-APCI and DA-APPI showed the radical cation of chlorobenzene at 0.05-0.1 mL/min flow rate, but at increasing flow rate, the abundance of chlorobenzene M+. decreased and reagent ion populations deriving from different gas-phase chemistry were recorded. The formation of these reagent ions explains the decreasing ionization efficiency and the differences in charge exchange between the techniques.

  7. Atmospheric Processing Module for Mars Propellant Production

    Science.gov (United States)

    Muscatello, A.; Devor, R.; Captain, J.

    2014-01-01

    The multi-NASA center Mars Atmosphere and Regolith COllector/PrOcessor for Lander Operations (MARCO POLO) project was established to build and demonstrate a methaneoxygen propellant production system in a Mars analog environment. Work at the Kennedy Space Center (KSC) Applied Chemistry Laboratory is focused on the Atmospheric Processing Module (APM). The purpose of the APM is to freeze carbon dioxide from a simulated Martian atmosphere containing the minor components nitrogen, argon, carbon monoxide, and water vapor at Martian pressures (approx. 8 torr) by using dual cryocoolers with alternating cycles of freezing and sublimation. The resulting pressurized CO(sub 2) is fed to a methanation subsystem where it is catalytically combined with hydrogen in a Sabatier reactor supplied by the Johnson Space Center (JSC) to make methane and water vapor. We first used a simplified once-through setup and later employed a H(sub 2)CO(sub 2) recycling system to improve process efficiency. This presentation and paper will cover (1) the design and selection of major hardware items, such as the cryocoolers, pumps, tanks, chillers, and membrane separators, (2) the determination of the optimal cold head design and flow rates needed to meet the collection requirement of 88 g CO(sub 2) hr for 14 hr, (3) the testing of the CO(sub 2) freezer subsystem, and (4) the integration and testing of the two subsystems to verify the desired production rate of 31.7 g CH(sub 4) hr and 71.3 g H(sub 2)O hr along with verification of their purity. The resulting 2.22 kg of CH(sub 2)O(sub 2) propellant per 14 hr day (including O(sub 2) from electrolysis of water recovered from regolith, which also supplies the H(sub 2) for methanation) is of the scale needed for a Mars Sample Return mission. In addition, the significance of the project to NASAs new Mars exploration plans will be discussed.

  8. Aqueous Phase Photo-Oxidation of Succinic Acid: Changes in Hygroscopic Properties and Reaction Products

    Science.gov (United States)

    Hudson, P. K.; Ninokawa, A.; Hofstra, J.; de Lijser, P.

    2013-12-01

    Atmospheric aerosol particles have been identified as important factors in understanding climate change. The extent to which aerosols affect climate is determined, in part, by hygroscopic properties which can change as a result of atmospheric processing. Dicarboxylic acids, components of atmospheric aerosol, have a wide range of hygroscopic properties and can undergo oxidation and photolysis reactions in the atmosphere. In this study, the hygroscopic properties of succinic acid aerosol, a non-hygroscopic four carbon dicarboxylic acid, were measured with a humidified tandem differential mobility analyzer (HTDMA) and compared to reaction products resulting from the aqueous phase photo-oxidation reaction of hydrogen peroxide and succinic acid. Reaction products were determined and quantified using gas chromatography-flame ionization detection (GC-FID) and GC-mass spectrometry (GC-MS) as a function of hydrogen peroxide:succinic acid concentration ratio and photolysis time. Although reaction products include larger non-hygroscopic dicarboxylic acids (e.g. adipic acid) and smaller hygroscopic dicarboxylic acids (e.g. malonic and oxalic acids), comparison of hygroscopic growth curves to Zdanovskii-Stokes-Robinson (ZSR) predictions suggests that the hygroscopic properties of many of the product mixtures are largely independent of the hygroscopicity of the individual components. This study provides a framework for future investigations to fully understand and predict the role of chemical reactions in altering atmospheric conditions that affect climate.

  9. Atmospheric deuterium fractionation: HCHO and HCDO yields in the CH2DO + O2 reaction

    Directory of Open Access Journals (Sweden)

    M. D. Hurley

    2007-11-01

    Full Text Available The formation of formaldehyde via hydrogen atom transfer from the methoxy radical to molecular oxygen is a key step in the atmospheric photochemical oxidation of methane, and in the propagation of deuterium from methane to molecular hydrogen. We report the results of the first investigation of the branching ratio for HCHO and HCDO formation in the CH2DO + O2 reaction. Labeled methoxy radicals (CH2DO were generated in a photochemical reactor by photolysis of CH2DONO. HCHO and HCDO concentrations were measured using FTIR spectroscopy. Significant deuterium enrichment was seen in the formaldehyde product, from which we derive a branching ratio of 88.2±1.1% for HCDO and 11.8±1.1% for HCHO. The implications of this fractionation on the propagation of deuterium in the atmosphere are discussed.

  10. High temperature reactions of WC-Co nanopowders in various atmospheres

    International Nuclear Information System (INIS)

    The melting of 30 nanometer size WC-6 w% and -15 w% Co particles, heated in hot chamber microscope under N2 atmosphere, was observed between 1130 oC and 1280 oC, i.e. under the equilibrium melting point of the WC-Co eutectics, 1320 oC. Such a dependence of the melting temperature of ultrafine particles on the grain size can be explained by Allen's model, or in case of a thin layer by a modified version of the model. At cooling, molten phases were observed down till 1190 oC, which shows the probability of chemical reactions occurred at high temperature, and the formation of compounds with lower melting points. Further experiments were carried out by heating the above samples in N2-1 v%CO and in N2-3,5 v%H2 atmospheres, in the chamber of the microscope. The samples were cooled down rapidly to room temperature, and the products were analyzed by x-ray diffractometry and by x-ray microanalysis. Several phases were found, which may help to describe possible solid-liquid-gas phase reactions between the components to be present either in the samples or in the atmosphere. (author)

  11. Evaluation of the atmospheric significance of multiphase reactions in atmospheric secondary organic aerosol formation

    Directory of Open Access Journals (Sweden)

    Gelencsér

    2005-01-01

    Full Text Available In a simple conceptual cloud-aerosol model the mass of secondary organic aerosol (SOA that may be formed in multiphase reaction in an idealized scenario involving two cloud cycles separated with a cloud-free period is evaluated. The conditions are set to those typical of continental clouds, and each parameter used in the model calculations is selected as a mean of available observational data of individual species for which the multiphase SOA formation route has been established. In the idealized setting gas and aqueous-phase reactions are both considered, but only the latter is expected to yield products of sufficiently low volatility to be retained by aerosol particles after the cloud dissipates. The key variable of the model is the Henry-constant which primarily determines how important multiphase reactions are relative to gas-phase photooxidation processes. The precursor considered in the model is assumed to already have some affinity to water, i.e. it is a compound having oxygen-containing functional group(s. As a principal model output an aerosol yield parameter is calculated for the multiphase SOA formation route as a function of the Henry-constant, and has been found to be significant already above H~103 M atm-1. Among the potential precursors that may be eligible for this mechanism based on their Henry constants, there are a suite of oxygenated compounds such as primary oxidation products of biogenic and anthropogenic hydrocarbons, including, for example, pinonaldehyde. Finally, the analogy of multiphase SOA formation to in-cloud sulfate production is exploited.

  12. Feasibility Study of Venus Surface Cooling Using Chemical Reactions with the Atmosphere

    Science.gov (United States)

    Evans, Christopher

    2013-01-01

    A literature search and theoretical analysis were conducted to investigate the feasibility of cooling a craft on Venus through chemical reformation of materials from the atmosphere. The core concept was to take carbon dioxide (CO2) from the Venus atmosphere and chemically reform it into simpler compounds such as carbon, oxygen, and carbon monoxide. This process is endothermic, taking energy from the surroundings to produce a cooling effect. A literature search was performed to document possible routes for achieving the desired reactions. Analyses indicated that on Venus, this concept could theoretically be used to produce cooling, but would not perform as well as a conventional heat pump. For environments other than Venus, the low theoretical performance limits general applicability of this concept, however this approach to cooling may be useful in niche applications. Analysis indicated that environments with particular atmospheric compositions and temperatures could allow a similar cooling system to operate with very good performance. This approach to cooling may also be useful where the products of reaction are also desirable, or for missions where design simplicity is valued. Conceptual designs for Venus cooling systems were developed using a modified concept, in which an expendable reactant supply would be used to promote more energetically favorable reactions with the ambient CO2, providing cooling for a more limited duration. This approach does not have the same performance issues, but the use of expendable supplies increases the mass requirements and limits the operating lifetime. This paper summarizes the findings of the literature search and corresponding analyses of the various cooling options.

  13. Feasibility Study of Venus Surfuce Cooling Using Chemical Reactions with the Atmosphere

    Science.gov (United States)

    Evans, Christopher

    2013-01-01

    A literature search and theoretical analysis were conducted to investigate the feasibility of cooling a craft on Venus through chemical reformation of materials from the atmosphere. The core concept was to take carbon dioxide (CO2) from the Venus atmosphere and chemically reform it into simpler compounds such as carbon, oxygen, and carbon monoxide. This process is endothermic, taking energy from the surroundings to produce a cooling effect. A literature search was performed to document possible routes for achieving the desired reactions. Analyses indicated that on Venus, this concept could theoretically be used to produce cooling, but would not perform as well as a conventional heat pump. For environments other than Venus, the low theoretical performance limits general applicability of this concept, however this approach to cooling may be useful in niche applications. Analysis indicated that environments with particular atmospheric compositions and temperatures could allow a similar cooling system to operate with very good performance. This approach to cooling may also be useful where the products of reaction are also desirable, or for missions where design simplicity is valued. Conceptual designs for Venus cooling systems were developed using a modified concept, in which an expendable reactant supply would be used to promote more energetically favorable reactions with the ambient CO2, providing cooling for a more limited duration. This approach does not have the same performance issues, but the use of expendable supplies increases the mass requirements and limits the operating lifetime. This paper summarizes the findings of the literature search and corresponding analyses of the various cooling options

  14. Charm and its production in neutrino reactions

    International Nuclear Information System (INIS)

    The present thesis gives a survey about the status of the studies of charmed particles. First the quark model is explained. Then it is shown how the spectroscopy of hadrons is extended, if one goes on from the three-quark model to the four-quark model. In the third chapter it is explained how from the weak interaction on the existence of the charmed quark can be concluded. Thereafter the evidences of the existence of a fourth quark from the e+e- annihilation are descrbed. Here also the detection of the J/psi is discussed which could be interpreted as bound state of a new quark-antiquark system and therefore proved the existence of a new quark. In the fifth chapter the production of charmed particles in neutrino experiments is described. Lepton pair events are discussed which showed that the fourth quark is identical with the theoretically predicted charmed quark. The sixth chapter deals with the direct observation of charmed particles in neutrino reactions and finishes with a determination of the production rate of charmed particles in the framework of the quark-parton model. In the seventh chapter the production of charmed particles in electromagnetic and hadronic interactions is discussed. Thereafter follows in the eight chapter a discussion of the decays of charmed particles. (orig./HSI)

  15. Sodium-water reaction product flow system

    International Nuclear Information System (INIS)

    Purpose: To provide the subject equipments wherein thermal insulating layers which neither exfoliate nor react by the impact due to high temperature sodium and hydrogen gas and are used for mitigating the thermal impact are provided on the inner surfaces of the emission system equipments, thereby preventing the destruction of the emission system equipments. Constitution: Thermal insulating layers are formed on the inner surfaces of sodium-water reaction product emission system equipments, that is, the inner surface of the emission system pipeline, that of the accommodation vessel and the surface of the cyclone separator, by film treatment, coating or heat resisting coating, and these surfaces are covered with the layers. Each of the layers is made of a material which does not cause a rapid reaction with high temperature sodium or hydrogen gas nor exfoliates and is withstandable for several seconds in which the thermal impact of at least the emission system comes into question, and its thickness is more than one capable of securing the necessary thermal resistance computed by the thermal impact analysis of the emission system. (Yoshihara, H.)

  16. Measuring OH Reaction Rate Constants and Estimating the Atmospheric Lifetimes of Trace Gases.

    Science.gov (United States)

    Orkin, Vladimir; Kurylo, Michael

    2015-04-01

    Reactions with hydroxyl radicals and photolysis are the main processes dictating a compound's residence time in the atmosphere for a majority of trace gases. In case of very short-lived halocarbons their reaction with OH dictates both the atmospheric lifetime and active halogen release. Therefore, the accuracy of OH kinetic data is of primary importance for the comprehensive modeling of a compound's impact on the atmosphere, such as in ozone depletion (i.e., the Ozone Depletion Potential, ODP) and climate change (i.e., the Global Warming Potential, GWP), each of which are dependent on the atmospheric lifetime of the compound. We have demonstrated the ability to conduct very high accuracy determinations of OH reaction rate constants over the temperature range of atmospheric interest, thereby decreasing the uncertainty of kinetic data to 2-3%. The atmospheric lifetime of a well-mixed compound due to its reaction with tropospheric hydroxyl radicals can be estimated by using a simple scaling procedure that is based on the results of field observations of methyl chloroform concentrations and detailed modeling of the OH distribution in the atmosphere. The currently available modeling results of the atmospheric fate of various trace gases allow for an improved understanding of the ability and accuracy of simplified semi-empirical estimations of atmospheric lifetimes. These aspects will be illustrated in this presentation for a variety of atmospheric trace gases.

  17. Reactions of uranium hexafluoride photolysis products

    Science.gov (United States)

    Lyman, John L.; Laguna, Glenn; Greiner, N. R.

    1985-01-01

    This paper confirms that the ultraviolet photolysis reactions of UF6 in the B band spectral region is simple bond cleavage to UF5 and F. The photolysis products may either recombine to UF6 or the UF5 may dimerize, and ultimately polymerize, to solid UF5 particles. We use four methods to set an upper limit for the rate constant for recombination of kr<2.0×10-12cm3 molecule-1 s-1. We measure the rate constant for UF5 dimerization to be kd=(1.0±0.2)×10-11 cm3 molecule-1 s-1. The principal method employed in these studies is the use of diode lasers to monitor, in real time, the changes in density of the species UF6 and UF5 after laser photolysis of the UF6 gas sample.

  18. First steps towards the reaction kinetics of HMDSO in an atmospheric pressure plasma jet in argon

    Science.gov (United States)

    Loffhagen, Detlef; Becker, Markus M.; Foest, Rüdiger; Schäfer, Jan; Sigeneger, Florian

    2014-10-01

    Hexamethyldisiloxane (HMDSO) is a silicon-organic compound which is often used as precursor for thin-film deposition by means of plasma polymerization because of its high deposition rate and low toxicity. To improve the physical understanding of the deposition processes, fundamental investigations have been performed to clarify the plasma-chemical reaction pathways of HMDSO and their effect on the composition and structure of the deposited film. The current contribution represents the main primary and secondary plasma-chemical processes and their reaction products in the effluent region of an argon plasma jet at atmospheric pressure. The importance of the different collision processes of electrons and heavy particles are discussed. Results of numerical modelling of the plasma jet and the Ar-HMDSO reaction kinetics indicate that the fragmentation of HMDSO is mainly initiated by collisions with molecular argon ions, while Penning ionization processes play a minor role for the reaction kinetics in the effluent region of the jet. The work has been supported by the German Research Foundation (DFG) under Grant LO 623/3-1.

  19. Assessment and Requirements of Nuclear Reaction Databases for GCR Transport in the Atmosphere and Structures

    Science.gov (United States)

    Cucinotta, F. A.; Wilson, J. W.; Shinn, J. L.; Tripathi, R. K.

    1998-01-01

    The transport properties of galactic cosmic rays (GCR) in the atmosphere, material structures, and human body (self-shielding) am of interest in risk assessment for supersonic and subsonic aircraft and for space travel in low-Earth orbit and on interplanetary missions. Nuclear reactions, such as knockout and fragmentation, present large modifications of particle type and energies of the galactic cosmic rays in penetrating materials. We make an assessment of the current nuclear reaction models and improvements in these model for developing required transport code data bases. A new fragmentation data base (QMSFRG) based on microscopic models is compared to the NUCFRG2 model and implications for shield assessment made using the HZETRN radiation transport code. For deep penetration problems, the build-up of light particles, such as nucleons, light clusters and mesons from nuclear reactions in conjunction with the absorption of the heavy ions, leads to the dominance of the charge Z = 0, 1, and 2 hadrons in the exposures at large penetration depths. Light particles are produced through nuclear or cluster knockout and in evaporation events with characteristically distinct spectra which play unique roles in the build-up of secondary radiation's in shielding. We describe models of light particle production in nucleon and heavy ion induced reactions and make an assessment of the importance of light particle multiplicity and spectral parameters in these exposures.

  20. Graphene Metal Adsorption as a Model Chemistry for Atmospheric Reactions

    OpenAIRE

    Ortiz, Y. P.; A. F. Jalbout

    2013-01-01

    We propose a mechanism by which chloromethane and dichloromethane decomposition reaction occurs on the surfaces of graphene. To this end we have performed calculations on the graphene surface with metal adsorption on the sheet on the opposite side of reactions to reduce the formation of free-radical intermediates.

  1. Electroweak meson production reaction in the nucleon resonance region

    International Nuclear Information System (INIS)

    We report on our recent study of the the neutrino-nucleon reaction in the nucleon resonance region. The dynamical reaction model of meson production reaction on the nucleon for the pion and photon induced reaction has been developed in order to investigate the spectrum of nucleon excited state. We have extended this model in order to describe the weak meson production reactions with the πN, ηN, KΛ, KΣ and ππN final states. We also studied the role of the final state interaction in the photon and the neutrino induced pion production reaction on the deuteron around the Δ(1232) resonance region

  2. A study of the atmospherically relevant reaction between molecular chlorine and dimethylsulfide (DMS): Establishing the reaction intermediate and measurement of absolute photoionization cross-sections

    International Nuclear Information System (INIS)

    In a study using UV photoelectron spectroscopy (PES) of the atmospherically relevant reactionCH3SCH3+Cl2->CH3SCH2Cl+HClbands associated with a reaction intermediate have been observed. These have been assigned to ionization of the covalently bound molecule (CH3)2SCl2 on the basis of the intensity of the observed bands as a function of reaction time, molecular orbital calculations of vertical ionization energies and evidence from infrared spectroscopy. A method has also been developed, with the flow-tube/PE spectrometer combination used, to measure photoionization cross-sections of the reagents and products at the photon energy utilized and this has allowed the photoionization cross-section of the intermediate to be estimated. This work augments an earlier study in which the rate constant of the reaction between CH3SCH3 (DMS) and Cl2 has been measured at room temperature

  3. Production and validation of nuclear reaction data

    International Nuclear Information System (INIS)

    Various research collaborations with foreign organizations such as IAEA, OECD, ORNL, BNL, etc. have been performed and strengthened. By actively participating in meetings that are sponsored by IAEA and OECD, we could make a decision on the research directions for nuclear data and offer our nuclear data to the international community without difficulty. Nuclear data uncertainty has been co-studied with ORNL, the calculation of evaluation module for the resonance areas and evaluation of nuclear data for reactor structural materials have completed in cooperation with BNL. Nuclear data that we produced were to be listed in ENDF/B-VII.1. With regard to evaluation techniques, a program to tune model parameters were developed. Covariance data production and a comparative analysis between nuclear data libraries for evaluating uncertainty was performed. Nuclear Data Evaluation module for resonance region and Uncertainty assessment techniques of the nuclear reactor analysis codes were developed. Evaluation was performed on the core material for nuclear fusion, advanced fuel cycle, and structural materials. Uncertainty calculations in the criticality are performed by using nuclear cross section uncertainty analysis system such as ERRORJ-ANISN-SUSD3D and NJOY-DANTSYS-SUSD3D. The number of nuclear materials for the fast reactor, radiation shielding, and actinide are processed and produced multigroup libraries were provided to the researchers. We adjusted the experiments using facilities that are distributed in the domestic research institutes. To build nuclear data measurement system using an electron accelerator in the Korea Atomic Energy Research Institute, conceptual design for fast neutron target and facility was completed. Neutron cross-section, photonuclear reaction was measured by using an electron accelerator in the Pohang neutron facility, The detector has been developed for more accurate measurements. Charged particle induced nuclear reaction cross sections were

  4. Transfer of atmospheric caesium to agricultural products

    International Nuclear Information System (INIS)

    A huge quantity of radioactive rubble was generated by the Great East Japan Earthquake. The Japanese government is considering incineration processing of such rubble in waste incinerators which have suitable equipment, and the government is urged to manage appropriately the radiation exposure of residents living in the vicinity of incinerators by inhalation and ingestion of food. In this study, we developed a model describing plant uptake of atmospheric caesium by direct deposition and root-absorption via soil. Analysis using our model has suggested that wet deposition contributes to transfer to a plant most, when caesium exists in the atmosphere. (author)

  5. Effect of Pozzolanic Reaction Products on Alkali-silica Reaction

    Institute of Scientific and Technical Information of China (English)

    WEI Fengyan; LAN Xianghui; LV Yinong; XU Zhongzi

    2006-01-01

    The effect of fly ash on controlling alkali-silica reaction (ASR) in simulated alkali solution was studied. The expansion of mortar bars and the content of Ca(OH)2 in cement paste cured at 80 ℃ for 91 d were measured. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were employed to study the microstructure of C-S-H. TEM/energy dispersive spectroscopy (EDS) was then used to determine the composition of C-S-H. The pore structure of the paste was analyzed by mercury intrusion porosimetry (MIP). The results show that the contents of fly ash of 30% and 45% can well inhibit ASR. And the content of Ca(OH)2 decreases with the increase of fly ash. That fly ash reacted with Ca(OH)2 to produce C-S-H with a low Ca/Si molar ratio could bind more Na+ and K+ ions, and produce a reduction in the amount of soluble alkali available for ASR. At the same time, the C-S-H produced by pozzolanic reaction converted large pores to smaller ones (gel pores smaller than 10 nm) to densify the pore structure. Perhaps that could inhibit alkali transport to aggregate for ASR.

  6. Inhibition of zinc-dependent peptidases by Maillard reaction products

    OpenAIRE

    Missagia de Marco, Leticia

    2015-01-01

    The Maillard reaction is a network of different non-enzymatic reactions between carbonyl groups of reducing sugars and amino groups from amino acids, peptides, or proteins, which progresses in three major stages and originates a very heterogeneous mixture of reaction products. It is also known as non-enzymatic browning, due to the brown macromolecular pigments formed in the final stage of the reaction. The chemistry underlying the Maillard reaction is complex. It encloses not only one reactio...

  7. Molecule-based approach for computing chemical-reaction rates in upper atmosphere hypersonic flows.

    Energy Technology Data Exchange (ETDEWEB)

    Gallis, Michail A.; Bond, Ryan Bomar; Torczynski, John Robert

    2009-08-01

    This report summarizes the work completed during FY2009 for the LDRD project 09-1332 'Molecule-Based Approach for Computing Chemical-Reaction Rates in Upper-Atmosphere Hypersonic Flows'. The goal of this project was to apply a recently proposed approach for the Direct Simulation Monte Carlo (DSMC) method to calculate chemical-reaction rates for high-temperature atmospheric species. The new DSMC model reproduces measured equilibrium reaction rates without using any macroscopic reaction-rate information. Since it uses only molecular properties, the new model is inherently able to predict reaction rates for arbitrary nonequilibrium conditions. DSMC non-equilibrium reaction rates are compared to Park's phenomenological non-equilibrium reaction-rate model, the predominant model for hypersonic-flow-field calculations. For near-equilibrium conditions, Park's model is in good agreement with the DSMC-calculated reaction rates. For far-from-equilibrium conditions, corresponding to a typical shock layer, the difference between the two models can exceed 10 orders of magnitude. The DSMC predictions are also found to be in very good agreement with measured and calculated non-equilibrium reaction rates. Extensions of the model to reactions typically found in combustion flows and ionizing reactions are also found to be in very good agreement with available measurements, offering strong evidence that this is a viable and reliable technique to predict chemical reaction rates.

  8. Dietary Maillard reaction products: implications for human health and disease

    OpenAIRE

    Ames, Jenny

    2009-01-01

    When foods are heat processed, the sugars and lipids react with the proteins they contain via the Maillard and related reactions to form a wide range of products. As a result, the sensory, safety, nutritional and health-promoting attributes of the foods are affected. Reaction products include advanced glycation/lipoxidation endproducts (AGE/ALEs), acrylamide and heterocyclic amines (HAA), all of which may impact on human health and disease. Furthermore, some Maillard reaction products affect ...

  9. Production, properties and application of steels resistant to atmospheric corrosion

    International Nuclear Information System (INIS)

    Steels, resistant to atmospheric corrosion, applied in the USSR and abroad, are reviewed. The influence of alloying elements (Cu, P, Cr, Si, Ni, Mo, Mn, As etc) upon resistance against atmospheric corrosion and mechanical properties of rolled steel is discussed. Technological properties, fields of the above steels application as well as the data on the range of product, are presented

  10. Middle atmosphere heating by exothermic chemical reactions involving odd-hydrogen species

    Science.gov (United States)

    Mlynczak, Martin G.; Solomon, Susan

    1991-01-01

    The rate of heating which occurs in the middle atmosphere due to four exothermic reactions involving members of the odd-hydrogen family is calculated. The following reactions are considered: O + OH yields O2 + H; H + O2 + M yields HO2 + M; H + O3 yields OH + O2; and O + HO2 yields OH + O2. It is shown that the heating rates due to these reactions rival the oxygen-related heating rates conventionally considered in middle-atmosphere models. The conversion of chemical potential energy into molecular translational energy (heat) by these odd-hydrogen reactions is shown to be a significant energy source in the middle atmosphere that has not been previously considered.

  11. Elusive anion growth in Titan's atmosphere: Low temperature kinetics of the C3N- + HC3N reaction

    Science.gov (United States)

    Bourgalais, Jérémy; Jamal-Eddine, Nour; Joalland, Baptiste; Capron, Michael; Balaganesh, Muthiah; Guillemin, Jean-Claude; Le Picard, Sébastien D.; Faure, Alexandre; Carles, Sophie; Biennier, Ludovic

    2016-06-01

    Ion chemistry appears to be deeply involved in the formation of heavy molecules in the upper atmosphere of Titan. These large species form the seeds of the organic aerosols responsible for the opaque haze surrounding the biggest satellite of Saturn. The chemical pathways involving individual anions remain however mostly unknown. The determination of the rates of the elementary reactions with ions and the identification of the products are essential to the progress in our understanding of Titan's upper atmosphere. We have taken steps in that direction through the investigation of the low temperature reactivity of C3N- , which was tentatively identified in the spectra measured by the CAPS-ELS instrument of the Cassini spacecraft during its high altitude flybys. The reaction of this anion with HC3N, one of the most abundant trace organics in the atmosphere, has been studied over the 49-294 K temperature range in uniform supersonic flows using the CRESU technique. The proton transfer is found to be the main exit channel (>91%) of the C315N- + HC3N reaction. It remains however indistinguishable with the non-isotopically labeled C314N- reactant. The T - 1 / 2 temperature dependence of this proton transfer reaction and its global rate are reasonably well reproduced theoretically using an average dipole orientation model. A minor exit channel, reactive detachment (products has not been determined. It is concluded that the C314N- + HC3N reaction cannot contribute to the growth of molecular anions in the upper atmosphere of Titan. Due to the low branching into the neutral exit channel, it cannot contribute either to the growth of neutrals even assuming a complete mass transfer.

  12. Products of fission, fusion and deep inelastic reactions

    International Nuclear Information System (INIS)

    Factors which influence the yields in heavy ion reactions such as fusion, fission fragment production and deep inelastic reactions are considered in the context of the design of spectroscopic experiments. Factors examined include the suitability of a reaction for a particular application, the expected yield of the required nucleus, and parameters responsible for uncertainties in predicted yields. (U.K.)

  13. Maillard reaction products in pet foods

    OpenAIRE

    Rooijen, van, J.

    2015-01-01

    Pet dogs and cats around the world are commonly fed processed commercial foods throughout their lives. Often heat treatments are used during the processing of these foods to improve nutrient digestibility, shelf life, and food safety. Processing is known to induce the Maillard reaction, in which a reducing sugar binds to a free reactive amino group of an amino acid. In intact proteins, the ε-amino group of lysine is the most abundant free amino group. The reaction reduces the bioavail...

  14. Plant surface reactions: an ozone defence mechanism impacting atmospheric chemistry

    Directory of Open Access Journals (Sweden)

    W. Jud

    2015-07-01

    Full Text Available Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. Plant injuries have been linked to the uptake of ozone through stomatal pores and oxidative damage of the internal leaf tissue. But a striking question remains: how much ozone effectively enters the plant through open stomata and how much is lost by chemical reactions at the plant surface? In this laboratory study we could show that semi-volatile organic compounds exuded by the glandular trichomes of different Nicotiana tabacum varieties are an efficient ozone sink at the plant surface. In our experiments, different diterpenoid compounds were responsible for a strongly variety dependent ozone uptake of plants under dark conditions, when stomatal pores are almost closed. Surface reactions of ozone were accompanied by prompt release of oxygenated volatile organic compounds, which could be linked to the corresponding precursor compounds: ozonolysis of cis-abienol (C20H34O – a diterpenoid with two exocyclic double bonds – caused emissions of formaldehyde (HCHO and methyl vinyl ketone (C4H6O. The ring-structured cembratrien-diols (C20H34O2 with three endocyclic double bonds need at least two ozonolysis steps to form volatile carbonyls such as 4-oxopentanal (C5H8O2, which we could observe in the gas phase, too. Fluid dynamic calculations were used to model ozone distribution in the diffusion limited leaf boundary layer under daylight conditions. In the case of an ozone-reactive leaf surface, ozone gradients in the vicinity of stomatal pores are changed in such a way, that ozone flux through the open stomata is strongly reduced. Our results show that unsaturated semi-volatile compounds at the plant surface should be considered as a source of oxygenated volatile organic compounds, impacting gas phase chemistry, as well as efficient ozone sink improving the ozone

  15. Acid-Catalyzed Reaction of Epoxides on Atmospheric Nanoparticles

    Science.gov (United States)

    Xu, W.; Gomez-Hernandez, M.; Lal, V.; Qiu, C.; Khalizov, A. F.; Wang, L.; Zhang, R.

    2013-12-01

    Aerosol plays an important role in affecting the earth climate and harming human health. Atmospheric aerosols can be formed from either primary emissions or gas-to-particle conversion process. Numerous studies, including both experimental and theoretical, have been carried out to elucidate the mechanism of gas-to-particle conversion process (a.k.a. nucleation) and the later growth stage of newly formed nanoparticles. However, a complete list of species involving in the nucleation and growth processes of nanoparticles is still poorly understood. The growth of newly formed sulfuric acid - water nanoparticles has been suggested to involve several potential organic vapors, such as amines, glyoxal, 2-4 hexadienal, and epoxides. In the present study, new formed sulfuric acid -water nanoparticles were size selected by a differential mobility analyzer and exposed to epoxide vapors. The size-change after exposure was detected using the second differential mobility analyzer. The size-enlarged particles were then collected by an electrostatic precipitator, thermal vaporized, and analyzed by an ion drift chemical ionization mass spectrometer. Our results show that the sizes of nanoparticles are increased considerably and the magnitude of the increment in size is size-dependent. Mass spectrometry analysis of the nanoparticles after exposure demonstrates that low volatile organosulfate and oligomers are formed in nanoparticles upon their exposure to epoxide vapors.

  16. Step Towards Modeling the Atmosphere of Titan: State-Selected Reactions of O+ with Methane

    Science.gov (United States)

    Hrušák, J.; Paidarová, I.

    2016-04-01

    Methane conversion and in particular the formation of the C-O bond is one of fundamental entries to organic chemistry and it appears to be essential for understanding parts of atmospheric chemistry of Titan, but, in broader terms it might be also relevant for Earth-like exoplanets. Theoretical study of the reactions of methane with atomic oxygen ion in its excited electronic states requires treating simultaneously at least 19 electronic states. Development of a computational strategy that would allow chemically reasonable and computationally feasible treatment of the CH4 (X)/O+ (2D, 2P) system is by far not trivial and it requires careful examination of all the complex features of the corresponding 19 potential energy surfaces. Before entering the discussion of the rich (photo) chemistry, inspection of the long range behavior of the system with focus on electric dipole transition moments is required. Our calculations show nonzero probability for the reactants to decay before entering the multiple avoided crossings region of the [CH4 + O → products]+ reaction. For the CH4/O+ (2P) system non-zero transition moment probabilities occur over the entire range of considered C-O distances (up to 15 Å), while for the CH4/O+ (2D) system these probabilities are lower by one order of magnitude and were found only at C-O distances smaller than 6 Å.

  17. Maillard reaction products in pet foods

    NARCIS (Netherlands)

    Rooijen, van C.

    2015-01-01

    Pet dogs and cats around the world are commonly fed processed commercial foods throughout their lives. Often heat treatments are used during the processing of these foods to improve nutrient digestibility, shelf life, and food safety. Processing is known to induce the Maillard reaction, in which a r

  18. High energy gamma-ray production in nuclear reactions

    International Nuclear Information System (INIS)

    Experimental techniques used to study high energy gamma-ray production in nuclear reactions are reviewed. High energy photon production in nucleus-nucleus collisions is discussed. Semi-classical descriptions of the nucleus-nucleus gamma reactions are introduced. Nucleon-nucleon gamma cross sections are considered, including theoretical aspects and experimental data. High energy gamma ray production in proton-nucleus reactions is explained. Theoretical explanations of photon emission in nucleus-nucleus collisions are treated. The contribution of charged pion currents to photon production is mentioned

  19. Studies of Atmospheric Chemistry and Reaction Mechanisms Using Optical Spectroscopy and Mass Spectrometry

    OpenAIRE

    Liu, Yingdi

    2011-01-01

    This thesis mainly focuses on (1) development and applications of cavity ringdown spectroscopy (CRDS) to study atmospheric trace gases; (2) reactive intermediates in the alkene ozonolysis reactions using photoionization time-of-flight mass spectrometry (TOFMS); and (3) development of new methods using CRDS for thin film studies.Specifically, CRDS based instruments are developed to measure and characterize peroxy radicals in atmosphere. By combining the chemical amplification detection of pero...

  20. Atmospheric chemistry of perfluorinated carboxylic acids: Reaction with OH radicals and atmospheric lifetimes

    DEFF Research Database (Denmark)

    Hurley, MD; Andersen, Mads Peter Sulbæk; Wallington, TJ;

    2004-01-01

    Relative rate techniques were used to study the kinetics of the reactions of OH radicals with a homologous series of perfluorinated acids, F(CF2)(n)COOH (n = 1, 2, 3, 4), in 700 Torr of air at 296 +/- 2 K. For n > 1, the length of the F(CF2)(n) group had no discernible impact on the reactivity of...

  1. A review of the rates of reaction of unirradiated uranium in gaseous atmospheres

    International Nuclear Information System (INIS)

    The review collates available quantitative rate data for the reaction of unirradiated uranium in dry and moist air, steam and carbon dioxide based atmospheres at temperatures ranging from room temperature to above the melting point of uranium. Reactions in nitrogen and carbon monoxide are also considered. The aim of the review is to provide a compilation of base data for the hazard analysis of fault conditions relating to Magnox fuel. (author)

  2. Kinetic and photochemical data for atmospheric chemistry reactions of the nitrogen oxides

    Science.gov (United States)

    Hampson, R. F., Jr.

    1980-01-01

    Data sheets for thermal and photochemical reactions of importance in the atmospheric chemistry of the nitrogen oxides are presented. For each reaction the available experimental data are summarized and critically evaluated, and a preferred value of the rate coefficient is given. The selection of the preferred value is discussed and an estimate of its accuracy is given. For the photochemical process, the data are summarized, and preferred for the photoabsorption cross section and primary quantum yields are given.

  3. Production, modification, and consumption of atmospheric trace gases by microorganisms

    OpenAIRE

    Schlegel, Prof. Dr. H. G.

    2011-01-01

    Some trace gases are contained in the atmosphere in appreciable amounts: methane, carbon monoxide, hydrogen, nitrous oxide. The bulk of these gases is of biological origin. Hydrogen is a primary product of microbial metabolism under anaerobic conditions. However, before reaching the atmosphere, it is converted by methane bacteria to methane, by nitrate reducing bacteria to nitrogen and to nitrous oxide and by sulfate reducing bacteria to hydrogen sulfide. Carbon monoxide is produced from cert...

  4. Adsorption and reaction of trace gas-phase organic compounds on atmospheric water film surfaces: a critical review.

    Science.gov (United States)

    Donaldson, D J; Valsaraj, Kalliat T

    2010-02-01

    The air-water interface in atmospheric water films of aerosols and hydrometeors (fog, mist, ice, rain, and snow) presents an important surface for the adsorption and reaction of many organic trace gases and gaseous reactive oxidants (hydroxyl radical (OH(.)), ozone (O(3)), singlet oxygen (O(2)((1)Delta(g))), nitrate radicals (NO(3)(.)), and peroxy radicals (RO(2)(.)). Knowledge of the air-water interface partition constant of hydrophobic organic species is necessary for elucidating the significance of the interface in atmospheric fate and transport. Various methods of assessing both experimental and theoretical values of the thermodynamic partition constant and adsorption isotherm are described in this review. Further, the reactivity of trace gases with gas-phase oxidants (ozone and singlet oxygen) at the interface is summarized. Oxidation products are likely to be more water-soluble and precursors for secondary organic aerosols in hydrometeors. Estimation of characteristic times shows that heterogeneous photooxidation in water films can compete effectively with homogeneous gas-phase reactions for molecules in the atmosphere. This provides further support to the existing thesis that reactions of organic compounds at the air-water interface should be considered in gas-phase tropospheric chemistry. PMID:20058916

  5. Exclusive hadron production in two photon reactions

    International Nuclear Information System (INIS)

    This paper summarises experimental results on exclusive hadron production in two photon collisions at electron positron storage rings and attempts some interpretation. Experimental know how is described and new suggestions are made for future analyses. New model calculations on resonance form factors and pair production amplitudes are presented. The two photon vertex is decomposed such that experiments can be parameterised with the minimal number of free parameters. Selection rules for off shell photon collisions are given in addition to Yang's theorems. (orig.)

  6. Aqueous-Phase Reactions of Isoprene with Sulfoxy Radical Anions as a way of Wet Aerosol Formation in the Atmosphere

    Science.gov (United States)

    Kuznietsova, I.; Rudzinski, K. J.; Szmigielski, R.; Laboratory of the Environmental Chemistry

    2011-12-01

    Atmospheric aerosols exhibit an important role in the environment. They have implications on human health and life, and - in the larger scale - on climate, the Earth's radiative balance and the cloud's formation. Organic matter makes up a significant fraction of atmospheric aerosols (~35% to ~90%) and may originate from direct emissions (primary organic aerosol, POA) or result from complex physico-chemical processes of volatile organic compounds (secondary organic aerosol, SOA). Isoprene (2-methyl-buta-1,3-diene) is one of the relevant volatile precursor of ambient SOA in the atmosphere. It is the most abundant non-methane hydrocarbon emitted to the atmosphere as a result of living vegetation. According to the recent data, the isoprene emission rate is estimated to be at the level of 500 TgC per year. While heterogeneous transformations of isoprene have been well documented, aqueous-phase reactions of this hydrocarbon with radical species that lead to the production of new class of wet SOA components such as polyols and their sulfate esters (organosulfates), are still poorly recognized. The chain reactions of isoprene with sulfoxy radical-anions (SRA) are one of the recently researched route leading to the formation of organosulfates in the aqueous phase. The letter radical species originate from the auto-oxidation of sulfur dioxide in the aqueous phase and are behind the phenomenon of atmospheric acid rain formation. This is a complicated chain reaction that is catalyzed by transition metal ions, such as manganese(II), iron(III) and propagated by sulfoxy radical anions . The presented work addresses the chemical interaction of isoprene with sulfoxy radical-anions in the water solution in the presence of nitrite ions and nitrous acid, which are important trace components of the atmosphere. We showed that nitrite ions and nitrous acid significantly altered the kinetics of the auto-oxidation of SO2 in the presence of isoprene at different solution acidity from 2 to 8

  7. Preparation and Reaction Mechanism of LaB6 Powder by Solid―state Reaction at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    XU Xiu-Hua,XIAO Han-Ning,GUO Wen-Ming,GAO Peng-Zhao,PENG Su-Hua

    2011-04-01

    Full Text Available The lanthanum hexaboride (LaB6) powders were synthesized under atmospheric pressure using B4C and La2O3 powder as the precursors. The thermodynamic conditions for preparing LaB6 at atmospheric pressure were calculated. The effects of temperature and holding time on the phase composition, morphology, particle size and distribution of LaB6 powders were characterized by X―ray diffraction (XRD), scanning electron microscope(SEM) and laser particle size anslyzer. The reaction mechanism was investigated. The results show that LaB6 powders obtained under atmospheric pressure at 1650 ¡䟦or 2h have cube structure with 99.22% purity after washed by hydrochloric acid. When the particle size of La2O3 powder is much smaller than that of B4C particle, the synthesis of LaB6 starts on the surface of B4C particle, then the residual La2O3 and LaBO3 will diffuse through LaB6 shell onto B4C core until the reaction is completely with the temperature rising and holding time prolonged. The initial shape and particle size of LaB6 powders are depending on that of B4C particles.

  8. Mutagenicity in Salmonella of a Simulated Urban-Smog Atmosphere Generated Using a Mobile Reaction Chamber

    Science.gov (United States)

    The EPA Mobile Reaction Chamber (MRC) is a 24-foot trailer containing a 14.3-m3 Teflon lined photochemical chamber used to generate simulated urban atmospheres. Photochemistry in the MRC is catalyzed by 120 fluorescent bulbs evenly mixed with black light bulbs and UV bulbs (300 &...

  9. A new transitory product in the ozonolysis of trans-2-butene at atmospheric pressure

    Science.gov (United States)

    Horie, O.; Moortgat, G. K.

    1989-03-01

    A previously unidentified transitory species, tentatively assigned as hydroxyethyl formate, CH 3CH (OH)-O-CHO, was formed as a major product in the ozonolysis of trans-2-butene at atmospheric pressure. A continuous stirred-tank reactor was used to analyze reaction products via molecular-beam sampling and matrix isolation FTIR spectroscopy. CH 3CHO, HCHO, CO 2, CO, CH 3OH, CH 4 and H 2O were the main, HCOOH and CH 2CO the minor, products. CH 3COOH and propene ozonide were detected as trace components.

  10. Resonance production in γγ reactions

    International Nuclear Information System (INIS)

    Experimental results on the exclusive production of resonances in γγ collisions are reviewed. These include new measurements of the radiative widths of the pseudoscalar (eta,eta') and the tensor mesons (f, A2, f'). A comparison of these results with SU(3) is made. Upper limits for other states than f in γγ -> ππ are given. The searches for γγ production of the states iota and theta as well as etasub(c) are presented and upper limits are given. Finally a limit is given for the rare decay f -> π+π-2π0. (orig.)

  11. A product study of the isoprene+NO3 reaction

    Directory of Open Access Journals (Sweden)

    A. Hansel

    2009-02-01

    Full Text Available Oxidation of isoprene through reaction with NO3 is a significant sink for isoprene that persists after dark. The products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene+NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF. The organic nitrate yield is found to be 62±6% and the combined yield of MACR+MVK is found to be ~10%. Additional hydrocarbon products, thought to be primarily C4 and C5 carbonyl compounds, were observed by the PTR-MS at various m/z ratios and their yields quantified. These other oxidation products are used as additional constraints on the reaction mechanism.

  12. A product study of the isoprene+NO3 reaction

    Directory of Open Access Journals (Sweden)

    R. C. Cohen

    2009-07-01

    Full Text Available Oxidation of isoprene through reaction with NO3 radicals is a significant sink for isoprene that persists after dark. The main products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene + NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF. The organic nitrate yield is found to be 65±12% of which the majority was nitrooxy carbonyls and the combined yield of methacrolein and methyl vinyl ketone (MACR+MVK is found to be ∼10%. PTR-MS measurements of nitrooxy carbonyls and TD-LIF measurements of total organic nitrates agreed well. The PTR-MS also observed a series of minor oxidation products which were tentatively identified and their yields quantified These other oxidation products are used as additional constraints on the reaction mechanism.

  13. Products of the Benzene + O(3P) Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Meloni, Giovanni; Trevitt, Adam J.; Epifanovsky, Evgeny; Krylov, Anna I.; Sirjean, Baptiste; Dames, Enoch; Wang, Hai

    2009-12-21

    The gas-phase reaction of benzene with O(3P) is of considerable interest for modeling of aromatic oxidation, and also because there exist fundamental questions concerning the prominence of intersystem crossing in the reaction. While its overall rate constant has been studied extensively, there are still significant uncertainties in the product distribution. The reaction proceeds mainly through the addition of the O atom to benzene, forming an initial triplet diradical adduct, which can either dissociate to form the phenoxy radical and H atom, or undergo intersystem crossing onto a singlet surface, followed by a multiplicity of internal isomerizations, leading to several possible reaction products. In this work, we examined the product branching ratios of the reaction between benzene and O(3P) over the temperature range of 300 to 1000 K and pressure range of 1 to 10 Torr. The reactions were initiated by pulsed-laser photolysis of NO2 in the presence of benzene and helium buffer in a slow-flow reactor, and reaction products were identified by using the multiplexed chemical kinetics photoionization mass spectrometer operating at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory. Phenol and phenoxy radical were detected and quantified. Cyclopentadiene and cyclopentadienyl radical were directly identified for the first time. Finally, ab initio calculations and master equation/RRKM modeling were used to reproduce the experimental branching ratios, yielding pressure-dependent rate expressions for the reaction channels, including phenoxy + H, phenol, cyclopentadiene + CO, which are proposed for kinetic modeling of benzene oxidation.

  14. EPR and NMR detection of transient radicals and reaction products

    International Nuclear Information System (INIS)

    Magnetic resonance methods in radiation chemistry are illustrated. The most recent developments in pulsed EPR and NMR studies in pulse radiolysis are outlined with emphasis on the study of transient radicals and their reaction products. 12 figures

  15. The Influence of CO2 Admixtures on the Product Composition in a Nitrogen-Methane Atmospheric Glow Discharge Used as a Prebiotic Atmosphere Mimic

    Science.gov (United States)

    Mazankova, V.; Torokova, L.; Krcma, F.; Mason, N. J.; Matejcik, S.

    2016-04-01

    This work extends our previous experimental studies of the chemistry of Titan's atmosphere by atmospheric glow discharge. The Titan's atmosphere seems to be similarly to early Earth atmospheric composition. The exploration of Titan atmosphere was initiated by the exciting results of the Cassini-Huygens mission and obtained results increased the interest about prebiotic atmospheres. Present work is devoted to the role of CO2 in the prebiotic atmosphere chemistry. Most of the laboratory studies of such atmosphere were focused on the chemistry of N2 + CH4 mixtures. The present work is devoted to the study of the oxygenated volatile species in prebiotic atmosphere, specifically CO2 reactivity. CO2 was introduced to the standard N2 + CH4 mixture at different mixing ratio up to 5 % CH4 and 3 % CO2. The reaction products were characterized by FTIR spectroscopy. This work shows that CO2 modifies the composition of the gas phase with the detection of oxygenated compounds: CO and others oxides. There is a strong influence of CO2 on increasing concentration other products as cyanide (HCN) and ammonia (NH3).

  16. Pion Production in High-Energy Neutrino Reactions with Nuclei

    CERN Document Server

    Mosel, Ulrich

    2015-01-01

    [Background] A quantitative understanding of neutrino interactions with nuclei is needed for precision era neutrino long baseline experiments (MINOS, NOvA, LBNE) which all use nuclear targets. Pion production is the dominant reaction channel at the energies of these experiments. [Purpose] Investigate the influence of nuclear effects on neutrino-induced pion production cross sections and compare predictions for pion-production with available data. [Method] The Giessen Boltzmann--Uehling--Uhlenbeck (GiBUU) model is used for the description of all incohrent channels in neutrino-nucleus reactions. [Results] Differential cross sections for charged and neutral pion production for the MINER$\

  17. The Heck reaction in the production of fine chemicals

    OpenAIRE

    Vries, Johannes G. de

    2001-01-01

    An overview is given of the use of the Heck reaction for the production of fine chemicals. Five commercial products have been identified that are produced on a scale in excess of 1 ton/year. The herbicide Prosulfuron™ is produced via a Matsuda reaction of 2-sulfonatobenzenediazonium on 3,3,3-trifluoropropene. The sunscreen agent 2-ethylhexyl p-methoxy-cinnamate has been produced on pilot scale using Pd/C as catalyst. Naproxen™ is produced via the Heck reaction of 2-bromo-6-methoxy-naphthalene...

  18. Atmospheric degradation of alkylfurans with chlorine atoms: Product and mechanistic study

    Science.gov (United States)

    Villanueva, F.; Cabañas, B.; Monedero, E.; Salgado, S.; Bejan, I.; Martin, P.

    As part of a study on the oxidation mechanism of heterocyclic aromatic compounds, some aspects of the atmospheric chemistry of several alkyl derivatives of furan have been investigated. The aim of this work was to identify the products of the reactions of chlorine atoms with 2-methylfuran, 2-ethylfuran and 2,5-dimethylfuran. Experiments were performed in two different smog chambers at 296 ± 2 K and 1000 ± 20 mbar of synthetic air. The experimental investigation was carried out using in situ long-path FTIR absorption spectroscopy and both SPME-GC/FID-ECD and SPME-GC/MS as sampling and detection techniques. The major primary products from the addition reaction channel were 4-oxo-2-pentenoyl chloride and formaldehyde for the reactions of 2-methylfuran and 2,5-dimethylfuran; 4-oxo-2-hexenoyl chloride and acetaldehyde for the reaction of 2-ethylfuran and 5-chloro-2(5H)-furanone for the reactions of both 2-methylfuran and 2-ethylfuran. Other minor products were 4-oxo-2-pentenal, 4-oxo-2-hexenal and 3-hexene-2,5-dione for the 2-methylfuran, 2-ethylfuran and 2,5-dimethylfuran reactions, respectively. From the abstraction pathway, HCl, furfural, 2-acetylfuran, 5-methylfurfural, maleic anhydride and 5-hydroxy-2(5H)-furanone were detected. The formation of furfural, 2-acetylfuran and 5-methylfurfural confirmed the H-atom abstraction from the alkyl group of 2-methylfuran, 2-ethylfuran and 2,5-dimethylfuran, respectively. This mechanism was not observed in previous studies with OH and NO 3 radicals. A mechanism is proposed to explain the main reaction products observed. The observed products confirm that addition of Cl atoms to the double bond of the alkylfuran is the dominant reaction pathway.

  19. Electromagnetic separators for recoiling reaction products

    International Nuclear Information System (INIS)

    This chapter describes the use of magnetic spectrometers and spectrographs, recoil mass spectrometers, and velocity filters as standard tools in many heavy-ion investigations. Topics considered include ion optics, examples of recoil selectors with static fields (the SHIP, the MIT-BNL energy-mass spectrometer, the MIT-BNL recoil-mass selector, the recoil-mass spectrometer at Michigan State University, the recoil-mass spectrometer at the University of Rochester, the Daresbury recoil separator, the MIT-ORNL recoil-mass selector), examples of recoil selectors with RF fields (the Munich RF separator, an RF separator proposed for GSI), magnetic spectrometers combined with time of flight (the GSI spectrometer, mirror-symmetric magnetic spectrometers), spectrometers for spallation products (the BEVALAC spectrometers, a proposed time-of-flight spectrometer for LAMPF), and technical aspects of electromagnetic separators (electric-field limitations, beam scattering)

  20. Duff reaction on phenols: Characterization of non steam volatile products

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; DeSouza, L.; Bhattacharya, J.

    New products having structures 1 and 2 have been characterized in the Duff reaction thymol arid carvacrol. These products have been identified as 2.6'-dithymylmethane 1 and 5.5' -dicarvacryl methane 2 respectively on the basis of spectral data...

  1. Charge Symmetry Breaking and Nuclear Pion Production Reactions

    CERN Document Server

    Bolton, Daniel R

    2011-01-01

    Large momentum transfer reactions such as pion production represent the frontier of Chiral Perturbation Theory and must be understood before more complex reactions can be considered. Pion production is also interesting in its own right, one application being the hadronic extraction of a charge symmetry breaking parameter: the contribution of the down-up quark mass difference to the neutron-proton mass difference. This dissertation reports on two primary projects: (1) a calculation of the charge symmetry breaking forward-backward asymmetry of the differential cross section of the n p -> d pi^0 reaction, and (2) the development of a new theoretical framework addressing the issue of reducibility in the impulse approximation's contribution to pion production. It is shown that the traditional one-body impulse approximation must be replaced by a two-body operator which makes a larger contribution to s-wave pion production.

  2. Kaon production in heavy ion reactions at intermediate energies

    CERN Document Server

    Fuchs, C

    2006-01-01

    The article reviews the physics related to kaon and antikaon production in heavy ion reactions at intermediate energies. Chiral dynamics predicts substantial modifications of the kaon properties in a dense nuclear environment. The status of the theoretical predictions as well as experimental evidences for medium effects such as repulsive/attractive mass shifts for $K^+/K^-$ are reviewed. In the vicinity of the thresholds, and even more pronounced below threshold, the production of strangeness is a highly collective process. Starting from elementary reaction channels the phenomenology of $K^+$ and $K^-$ production, i.e. freeze-out densities, time scales etc. as derived from experiment and theoretical transport calculations is presented. Below threshold kaon production shows a high sensitivity on the nuclear compression reached in heavy ion reactions. This allows to put constraints on the nuclear equation-of-state which are finally discussed.

  3. Modelling of OH production in cold atmospheric-pressure He–H2O plasma jets

    International Nuclear Information System (INIS)

    Results of the modelling of OH production in the plasma bullet mode of cold atmospheric-pressure He–H2O plasma jets are presented. It is shown that the dominant source of OH molecules is related to the Penning and charge transfer reactions of H2O molecules with excited and charged helium species produced by guided streamers (plasma bullets), in contrast to the case of He–H2O glow discharges where OH production is mainly due to the dissociation of H2O molecules by electron impact. (paper)

  4. Reactions of substituted benzene anions with N and O atoms: Chemistry in Titan's upper atmosphere and the interstellar medium

    Science.gov (United States)

    Wang, Zhe-Chen; Bierbaum, Veronica M.

    2016-06-01

    The likely existence of aromatic anions in many important extraterrestrial environments, from the atmosphere of Titan to the interstellar medium (ISM), is attracting increasing attention. Nitrogen and oxygen atoms are also widely observed in the ISM and in the ionospheres of planets and moons. In the current work, we extend previous studies to explore the reactivity of prototypical aromatic anions (deprotonated toluene, aniline, and phenol) with N and O atoms both experimentally and computationally. The benzyl and anilinide anions both exhibit slow associative electron detachment (AED) processes with N atom, and moderate reactivity with O atom in which AED dominates but ionic products are also formed. The reactivity of phenoxide is dramatically different; there is no measurable reaction with N atom, and the moderate reactivity with O atom produces almost exclusively ionic products. The reaction mechanisms are studied theoretically by employing density functional theory calculations, and spin conversion is found to be critical for understanding some product distributions. This work provides insight into the rich gas-phase chemistry of aromatic ion-atom reactions and their relevance to ionospheric and interstellar chemistry.

  5. Ab initio studies of the kinetic isotope effect of the CH4 + OH atmospheric reaction

    Science.gov (United States)

    Lasaga, Antonio C.; Gibbs, G. V.

    1991-07-01

    High level ab initio calculations have been carried out on the C-13 - C-12 kinetic isotope effect of the CH4 + OH reaction in the atmosphere. The results agree quite well with both the absolute value of the isotope effect and the temperature dependence of the effect, based on new experimental data. The calculated kinetic isotope effect supports a bigger effect of biomass burning on the methane global budget.

  6. Role of reaction atmosphere in preparation of potassium tantalate through sol-gel method

    Czech Academy of Sciences Publication Activity Database

    Buršík, Josef; Vaněk, Přemysl; Mika, Filip

    2013-01-01

    Roč. 68, č. 2 (2013), s. 219-233. ISSN 0928-0707 R&D Projects: GA ČR GA13-03708S; GA MŠk ED0017/01/01 Institutional support: RVO:61388980 ; RVO:68378271 ; RVO:68081731 Keywords : Potassium tantalate * thin films * Sol-gel * crystallization * reaction atmosphere Subject RIV: CA - Inorganic Chemistry; JA - Electronics ; Optoelectronics, Electrical Engineering (UPT-D) Impact factor: 1.547, year: 2013

  7. Thermochemical Reactions for Solar Energy Storage and Fuel Production

    OpenAIRE

    Roeb, Martin; Sattler, Christian

    2013-01-01

    Thermochemical multistep processes are promising options to face future energy problems. Such reactions can be used to enhance the availability of solar energy in terms of energy transport, of energy demand/supply management and of potential energy related applications. Coupling concentrated sunlight to suitable sequences of thermochemical reaction enables the production of hydrogen, syngas and other fuels derived from those precursors by water- and CO2-splitting as well as the storage of sol...

  8. Reactions of SIV species with organic compounds: formation mechanisms of organo-sulfur derivatives in atmospheric aerosols

    Science.gov (United States)

    Passananti, Monica; Shang, Jing; Dupart, Yoan; Perrier, Sébastien; George, Christian

    2015-04-01

    Secondary organic aerosol (SOA) have an important impact on climate, air quality and human health. However the chemical reactions involved in their formation and growth are not fully understood or well-constrained in climate models. It is well known that inorganic sulfur (mainly in oxidation states (+IV) and (+VI)) plays a key role in aerosol formation, for instance sulfuric acid is known to be a good nucleating gas. In addition, acid-catalyzed heterogeneous reactions of organic compounds has shown to produce new particles, with a clear enhancement in the presence of ozone (Iinuma 2013). Organosulfates have been detected in tropospheric particles and aqueous phases, which suggests they are products of secondary organic aerosol formation process (Tolocka 2012). Originally, the production of organosulfates was explained by the esterification reaction of alcohols, but this reaction in atmosphere is kinetically negligible. Other formation pathways have been suggested such as hydrolysis of peroxides and reaction of organic matter with sulfite and sulfate radical anions (SO3-, SO4-) (Nozière 2010), but it remains unclear if these can completely explain atmospheric organo-sulfur aerosol loading. To better understand the formation of organo-sulfur compounds, we started to investigate the reactivity of SIV species (SO2 and SO32-) with respect to specific functional groups (organic acids and double bonds) on atmospherically relevant carboxylic acids and alkenes. The experiments were carried out in the homogeneous aqueous phase and at the solid-gas interface. A custom built coated-wall flow tube reactor was developed to control relativity humidity, SO2 concentration, temperature and gas flow rate. Homogeneous and heterogeneous reaction kinetics were measured and resulting products were identified using liquid chromatography coupled with an orbitrap mass spectrometer (LC-HR-MS). The experiments were performed with and without the presence of ozone in order to evaluate any

  9. Atmospheric chemistry of CF3C(O)O2 radicals. Kinetics of their reaction with NO2 and kinetics of the thermal decomposition of the product CF3C(O)O2NO2

    DEFF Research Database (Denmark)

    Wallington, T.J.; Sehested, J.; Nielsen, O.J.

    A pulse radiolysis technique has been used to measure a rate constant of (6.6 +/- 1.3) x 10(-12) cm3 molecule-1 s-1 for the association reaction between CF3C(O)O2 radicals and NO2 at 295 K and one atmosphere total pressure of SF6 diluent. A FTIR/smog chamber system was used to study the thermal...

  10. Λ-hypernucleus production in proton-induced reaction

    International Nuclear Information System (INIS)

    The Λ-hypernucleus (LHN) production in the proton-induced reaction is studied in the distorted wave impulse approximation(DWIA). The cross sections for the LHN production in the reactions where the proton bombards the 6Li, 12C and 16O targets, respectively, are calculated. It is shown that the reaction cross sections are of the order of µb, and the distortion effects tend to reduce the cross sections by a factor of 3~10. For the sΛ–LHN production, the differential cross section is decreased with the increasing mass of the target nucleus. The pΛ–LHN production cross section is normally higher than that for the sΛ–LHN production. The double differential cross sections (DDXS) with respect to the momenta of the outgoing proton and kaon are also demonstrated. The missing mass spectra of the inclusive reaction p+A → p+K++X for the 6Li, 12C and 16O targets, an alternative way to study hypernuclear physics, are proposed. From these spectra, the masses of LHN can accurately be extracted. Moreover, the exotic LHN production in the same type of reaction is also studied . The same physical quantities are calculated. It is shown that the magnitude of the cross section is also in the order of µb. The halo effect of the core nucleus that locates at a place far away from the stable line would make the wave function broader, and consequently reduces the production cross section. (author)

  11. Variations in product in reactions of naphthoquinone with primary amines

    Directory of Open Access Journals (Sweden)

    Barooah Nilotpal

    2007-03-01

    Full Text Available Abstract Reaction of 1,2-naphthoquinone with primary amines gives a 2-amino-1,4-naphthoquinone derivative which is equivalent to 1,2 to 1,4 carbonyl transposition. For example the reaction of 1,2-naphthoquinone with 4-methoxyaniline gives 2-(4-methoxyanilino-naphthoquinone-1,4-(4-methoxyanil (1 and with n-butylamine gives 2-(butylamino-naphthoquinone-1,4-butylimine (2 respectively. The compounds 1 and 2 are characterized by X-ray crystallography; they have hydrogen-bonded dimeric structures. Similar reaction of 1,4-naphthoquinone with 3-picolylamine and 4-picolylamine gives the corresponding 2-amino 1,4-naphthoquinones; two products are characterized by X-ray crystallography. The reaction of 1,4-naphthoquinone with 4-aminothiophenol and 1,4-naphthoquinone with 4-aminophenol are compared. The former leads to C-S and the latter to C-N bond formation. The reaction of 1,4-naphthoquinone with 4-aminothiophenol in an NMR tube is studied to explain that 2-(4-anilinothiolato 1,4-naphthoquinone derivative to be the sole product in the reaction.

  12. Controlling the NO production of an atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    The production of NO radicals by an atmospheric pressure plasma jet has been investigated by means of absorption spectroscopy in the mid-infrared region (IR) and optical emission spectroscopy (OES) in the ultraviolet (UV) part of the spectrum. The plasma jet investigated here operates in argon with air admixtures up to 1%. The study shows that OES can be used to characterize the relative NO production at small air admixtures. The Production of NO radicals can be controlled by variation of air admixture. Important to note—especially for operation in ambient conditions—is that a small addition of water vapour strongly affects the production of NO radicals especially at higher air admixtures (greater than 0.2%). (paper)

  13. Kinetics and Product Yields of the Gas-Phase Reactions of Isoprene Hydroxynitrates and Isoprene Carbonynitrates

    Science.gov (United States)

    Abdelhamid, A.; Addala, R.; Vizenor, N.; Scruggs, A.; Tyndall, G. S.; Orlando, J. J.; Le, T.; Cardenas, E.; Maitra, S.; Hasson, A. S.

    2013-12-01

    Isoprene nitrates are formed in the troposphere from the reactions of isoprene with OH in the presence of NOx during the day and with NO3 during the night. Depending on their subsequent reactions, these compounds may be reservoirs or sinks for NOx, and may contribute to secondary organic aerosol formation. In this work, two isoprene hydroxynitrates (CH2=CHC(ONO2)(CH3)CH2OH, 1,2-IHN and CH2OHCH(ONO2)C(CH3)=CH2, 4,3-IHN ) and one isoprene carbonyl nitrate (CH2=CHC(ONO2)(CH3)CHO, ICN)) were synthesized. The kinetics and product yields from their reaction with O3, OH, NO3 and Cl were then investigated in a photochemical reactor using a combination of long-path Fourier transform infra-red spectroscopy, proton transfer reaction mass spectrometry and gas chromatography with flame ionization detection. Measured rate coefficients are consistent with reaction with OH and NO3 as the major chemical sinks for these compounds. Measured product yields imply that NOx is not released from these compounds in their reactions with atmospheric oxidants.

  14. The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

    OpenAIRE

    Kalesse, Markus; Cordes, Martin; Symkenberg, Gerrit; Lu, Hai-Hua

    2014-01-01

    The vinylogous Mukaiyama aldol reaction (VMAR) allows efficient access to larger segments for complex natural product synthesis, primarily polyketides, through the construction of vicinal hydroxyl and methyl groups as well as di and tri-substituted double bonds in one single operation. In this review, we will highlight stereoselective protocols that have been used in natural product synthesis and cluster them into the four groups that can be obtained from different silyl ketene acetals or eno...

  15. Stochastic aspects of multiparticle production in relativistic nuclear reactions

    International Nuclear Information System (INIS)

    Midrapidity multiparticle production process in ordinary hadron and heavy-ion induced reactions at sufficiently high incident energies are analyzed. It is shown that stochastic aspects of multiparticle production process in relativistic range plays a dominating role in understanding the observable phenomena. The basic idea and the main results of the multisource model for hadron-nucleus and nucleus-nucleus collisions are shown. The concept of the NES (number of effective sources) scaling is discussed. 16 refs.; 7 figs

  16. Measurement of exclusive eta' production in γγ reactions

    International Nuclear Information System (INIS)

    We observe γγ->eta' production in the reaction e+e- -> e+e-π+π-γ. We measure the product GAMMAsub(γγ)(eta')B(eta' -> rho0γ) to be 1.14+-0.08+-0.11 keV. A first measurement of the γγ->eta' transition form factor is made for Q2 up to 1 GeV2. (orig.)

  17. Strangeness production and hypernucleus formation in antiproton induced reactions

    CERN Document Server

    Feng, Zhao-Qing

    2015-01-01

    Formation mechanism of fragments with strangeness in collisions of antiprotons on nuclei has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport approach combined with a statistical model (GEMINI) for describing the decays of excited fragments. Production of strange particles in the antiproton induced nuclear reactions is modeled within the LQMD model, in which all possible reaction channels such as elastic scattering, annihilation, charge exchange and inelastic scattering in antibaryon-baryon, baryon-baryon and meson-baryon collisions have been included. A coalescence approach is developed for constructing hyperfragments in phase space after de-excitation of nucleonic fragments. The combined approach could describe the production of fragments in low-energy antiproton induced reactions. Hyperfragments are formed within the narrower rapidities and lower kinetic energies. It has advantage to produce heavier hyperfragments and hypernuclides with strangeness s=-2 (double-$\\Lambda$ fra...

  18. Modeling of atmospheric OH reaction rates using newly developed variable distance weighted zero order connectivity index

    Science.gov (United States)

    Markelj, Jernej; Pompe, Matevž

    2016-04-01

    A new variable distance weighted zero order connectivity index was used for development of structure-activity relationship for modeling reactivity of OH radical with alkanes and non-conjugated alkenes in the atmosphere. The proposed model is based on the assumptions that the total reaction rate can be obtained by summing all partial reaction rates and that all reaction sites are interrelated by influencing each other. The results suggest that these assumptions are justified. The model was compared with the EPA implemented model in the studied application domain and showed superior prediction capabilities. Further, optimized values of the weights that were used in our model permit some insight into mechanisms that govern the reaction OH + alkane/alkene. The most important conclusion is that the branching degree of the forming radical seems to play a major role in site specific reaction rates. Relative qualitative structural interpretation is possible, e.g. allylic site is suggested to be much more reactive than even tertiary sp3 carbon. Novel modeling software MACI, which was developed in our lab and is now available for research purposes, was used for calculations. Various variable topological indices that are again starting to be recognized because of their great potentials in simplicity, fast calculations, very good correlations and structural information, were implemented in the program.

  19. Gas-Phase Reactions of Methoxyphenols with NO3 Radicals: Kinetics, Products, and Mechanisms.

    Science.gov (United States)

    Zhang, Haixu; Yang, Bo; Wang, Youfeng; Shu, Jinian; Zhang, Peng; Ma, Pengkun; Li, Zhen

    2016-03-01

    Methoxyphenols, a group of important tracers for wood smoke, are emitted to the atmosphere in large quantities, but their transformations are rarely studied. In this study, the kinetics and products of the gas-phase reactions of eugenol and 4-ethylguaiacol with NO3 radicals were investigated online using a vacuum ultraviolet photoionization gas time-of-flight mass spectrometer. The rate coefficients of the gaseous reactions of eugenol and 4-ethylguaiacol with NO3 radicals were (1.6 ± 0.4) × 10(-13) and (1.1 ± 0.2) × 10(-12) cm(3) molecule(-1) s(-1) (at 298 K), indicating that the atmospheric lifetimes of the NO3 radicals were 3.5 and 0.5 h, respectively. With the aid of gas-chromatography-mass-spectrometry analysis, several types of degradation products were identified with nitro derivatives as the major products. The configurations of the nitro-product isomers and their formation mechanisms were determined via theoretical calculations. On the basis of these products, degradation pathways of the methoxyphenols with NO3 radicals were proposed. This study determines the degradation rates and mechanisms of the methoxyphenols at night and implies the significant NO3 nighttime chemistry. PMID:26845070

  20. Biodiesel production via injection of superheated methanol technology at atmospheric pressure

    International Nuclear Information System (INIS)

    Highlights: • Non-catalytic superheated methanol for biodiesel production is developed. • Crude Jatropha curcas oil with high FFA can be directly used as oil feedstock. • High content of biodiesel can be produced. • Separation of FAME and glycerol from the sample product is easy. - Abstract: In this high demand of renewable energy market, biodiesel was extensively produced via various catalytic and non-catalytic technologies. Conventional catalytic transesterification for biodiesel production has been shown to have limitation in terms of sensitivity to high water and free fatty acid, complicated separation and purification of biodiesel. In this study, an alternative and innovative approach was carried out via non-catalytic superheated methanol technology to produce biodiesel. Similar to supercritical reaction, the solvent need to be heated beyond the critical temperature but the reactor pressure remained at 0.1 MPa (atmospheric pressure). Transesterification reaction with superheated methanol was carried out at different reaction temperature within the limit of 270–300 °C and at different methanol flow rate ranging from 1 ml/min to 3 ml/min for 4 h. Results obtained showed that the highest biodiesel yield at 71.54% w/w was achieved at reaction temperature 290 °C and methanol flow rate at 2 ml/min with 88.81% w/w FAME content, implying the huge potential of superheated technology in producing FAME

  1. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Science.gov (United States)

    Bouvier-Brown, N. C.; Goldstein, A. H.; Worton, D. R.; Matross, D. M.; Gilman, J. B.; Kuster, W. C.; Welsh-Bon, D.; Warneke, C.; de Gouw, J. A.; Cahill, T. M.; Holzinger, R.

    2009-03-01

    We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments - a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) - and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4-68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72-10.2 μgCg-1 h-1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  2. Optimization of the production of ethyl esters by ultrasound assisted reaction of soybean oil and ethanol

    Directory of Open Access Journals (Sweden)

    S. Rodrigues

    2009-06-01

    Full Text Available Biodiesel is a renewable liquid fuel that can be produced by a transesterification reaction between a vegetable oil and an alcohol. This paper evaluates and optimizes the production of ethyl esters (biodiesel from soybean oil and ethanol. The reaction was carried out by applying ultrasound under atmospheric pressure and ambient temperature. Response surface methodology was used to evaluate the influence of alcohol to oil molar ratio and catalyst concentration on the yield of conversion of soybean oil into ethyl esters. The process resulted in a maximum yield of 91.8% after 30 minutes of reaction. The process variables alcohol to oil ratio and catalyst to oil ratio were statistically significant regarding the yield of ethyl esters. The optimal operating condition was obtained applying an alcohol to oil molar ratio of 10.2 and a catalyst to oil weight ratio of 0.0035.

  3. Interplay between diffusion, accretion and nuclear reactions in the atmospheres of Sirius and Przybylski's star

    CERN Document Server

    Yushchenko, A; Goriely, S; Shavrina, A; Kang, Y W; Rostopchin, S; Valyavin, G; Mkrtichian, D; Hatzes, A; Lee, B C; Kim, C; Yushchenko, Alexander; Gopka, Vera; Goriely, Stephane; Shavrina, Angelina; Kang, Young Woon; Rostopchin, Sergey; Valyavin, Gennady; Mkrtichian, David; Hatzes, Artie; Lee, Byeong-Cheol; Kim, Chulhee

    2006-01-01

    The abundance anomalies in chemically peculiar B-F stars are usually explained by diffusion of chemical elements in the stable atmospheres of these stars. But it is well known that Cp stars with similar temperatures and gravities show very different chemical compositions. We show that the abundance patterns of several stars can be influenced by accretion and (or) nuclear reactions in stellar atmospheres. We report the result of determination of abundances of elements in the atmosphere of hot Am star: Sirius A and show that Sirius A was contaminated by s-process enriched matter from Sirius B (now a white dwarf). The second case is Przybylski's star. The abundance pattern of this star is the second most studied one after the Sun with the abundances determined for about 60 chemical elements. Spectral lines of radioactive elements with short decay times were found in the spectrum of this star. We report the results of investigation on the stratification of chemical elements in the atmosphere of Przybylski's star ...

  4. Reaction pathways of the formation of molecular products upon dissolution

    International Nuclear Information System (INIS)

    Molecular products of γ-irradiated crystal lactose formed by its dissolving in water were identified by UV-spectroscopy, high effective liquid chromatography and chemical analysis. Effect of shelf life of the irradiated lactose crystals, pH of solvent and presence of oxygen on the composition of finished products of this hydrocarbon is studied. It is demonstrated that one part of molecular products is formed from post-radiation reactions of radicals in crystals and other - in the process of dissolving of solid samples

  5. Open charm and beauty production in hadron reactions

    Energy Technology Data Exchange (ETDEWEB)

    Lykasov, G.I.; Lyubushkin, V.V.; Bednyakov, V.A. [Joint Institute for Nuclear Research, 141980, Dubna, Moscow region (Russian Federation)

    2010-01-15

    The production of charmed and beauty hadrons in proton-proton and proton-antiproton collisions at high energies is analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. It is shown that using both the QGSM and NLO QCD one can describe these experimental data rather successfully in a wide region of transverse momenta. We also present some predictions for the future experiments on the beauty baryon production in pp collisions at LHC energies and on the charmed meson production in p-bar p reactions at GSI energies.

  6. Clocking Surface Reaction by In-Plane Product Rotation.

    Science.gov (United States)

    Anggara, Kelvin; Huang, Kai; Leung, Lydie; Chatterjee, Avisek; Cheng, Fang; Polanyi, John C

    2016-06-15

    Electron-induced reaction of physisorbed meta-diiodobenzene (mDIB) on Cu(110) at 4.6 K was studied by Scanning Tunneling Microscopy and molecular dynamics theory. Single-electron dissociation of the first C-I bond led to in-plane rotation of an iodophenyl (IPh) intermediate, whose motion could be treated as a "clock" of the reaction dynamics. Alternative reaction mechanisms, successive and concerted, were observed giving different product distributions. In the successive mechanism, two electrons successively broke single C-I bonds; the first C-I bond breaking yielded IPh that rotated directionally by three different angles, with the second C-I bond breaking giving chemisorbed I atoms (#2) at three preferred locations corresponding to the C-I bond alignments in the prior rotated IPh configurations. In the concerted mechanism a single electron broke two C-I bonds, giving two chemisorbed I atoms; significantly these were found at angles corresponding to the C-I bond direction for unrotated mDIB. Molecular dynamics accounted for the difference in reaction outcomes between the successive and the concerted mechanisms in terms of the time required for the IPh to rotate in-plane; in successive reaction the time delay between first and second C-I bond-breaking events allowed the IPh to rotate, whereas in concerted reaction the computed delay between excitation and reaction (∼1 ps) was too short for molecular rotation before the second C-I bond broke. The dependence of the extent of motion at a surface on the delay between first and second bond breaking suggested a novel means to "clock" sub-picosecond dynamics by imaging the products arising from varying time delays between impacting pairs of electrons. PMID:27191189

  7. Implicit coupling of turbulent diffusion with chemical reaction mechanisms for prognostic atmospheric dispersion models

    Energy Technology Data Exchange (ETDEWEB)

    Berlowitz, D.R.

    1996-11-01

    In the last few decades the negative impact by humans on the thin atmospheric layer enveloping the earth, the basis for life on this planet, has increased steadily. In order to halt, or at least slow down this development, the knowledge and study of these anthropogenic influence has to be increased and possible remedies have to be suggested. An important tool for these studies are computer models. With their help the atmospheric system can be approximated and the various processes, which have led to the current situation can be quantified. They also serve as an instrument to assess short or medium term strategies to reduce this human impact. However, to assure efficiency as well as accuracy, a careful analysis of the numerous processes involved in the dispersion of pollutants in the atmosphere is called for. This should help to concentrate on the essentials and also prevent excessive usage of sometimes scarce computing resources. The basis of the presented work is the EUMAC Zooming Model (ETM), and particularly the component calculating the dispersion of pollutants in the atmosphere, the model MARS. The model has two main parts: an explicit solver, where the advection and the horizontal diffusion of pollutants are calculated, and an implicit solution mechanism, allowing the joint computation of the change of concentration due to chemical reactions, coupled with the respective influence of the vertical diffusion of the species. The aim of this thesis is to determine particularly the influence of the horizontal components of the turbulent diffusion on the existing implicit solver of the model. Suggestions for a more comprehensive inclusion of the full three dimensional diffusion operator in the implicit solver are made. This is achieved by an appropriate operator splitting. A selection of numerical approaches to tighten the coupling of the diffusion processes with the calculation of the applied chemical reaction mechanisms are examined. (author) figs., tabs., refs.

  8. Sorption enhanced reaction process (SERP) for production of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Sircar, S.; Anand, M.; Carvill, B. [Air Products and Chemicals, Inc., Allentown, PA (United States)] [and others

    1995-09-01

    Sorption Enhanced Reaction (SER) is a novel process that is being developed for the production of lower cost hydrogen by steam-methane reforming (SMR). In this process, the reaction of methane with steam is carried out in the presence of an admixture of a catalyst and a selective adsorbent for carbon dioxide. The consequences of SER are: (1) reformation reaction at a significantly lower temperature (300-500{degrees}C) than conventional SMR (800-1100{degrees}C), while achieving the same conversion of methane to hydrogen, (2) the product hydrogen is obtained at reactor pressure (200-400 psig) and at 99+% purity directly from the reactor (compared to only 70-75% H{sub 2} from conventional SMR reactor), (3) downstream hydrogen purification step is either eliminated or significantly reduced in size. The early focus of the program will be on the identification of an adsorbent/chemisorbent for CO{sub 2} and on the demonstration of the SER concept for SMR in our state-of-the-art bench scale process. In the latter stages, a pilot plant will be built to scale-up the technology and to develop engineering data. The program has just been initiated and no significant results for SMR will be reported. However, results demonstrating the basic principles and process schemes of SER technology will be presented for reverse water gas shift reaction as the model reaction. If successful, this technology will be commercialized by Air Products and Chemicals, Inc. (APCI) and used in its existing hydrogen business. APCI is the world leader in merchant hydrogen production for a wide range of industrial applications.

  9. Gas Sensor Evaluations in Polymer Combustion Product Atmospheres

    Science.gov (United States)

    Delgado, Rafael H.; Davis, Dennis D.; Beeson, Harold D.

    1999-01-01

    Toxic gases produced by the combustion or thermo-oxidative degradation of materials such as wire insulation, foam, plastics, or electronic circuit boards in space shuttle or space station crew cabins may pose a significant hazard to the flight crew. Toxic gas sensors are routinely evaluated in pure gas standard mixtures, but the possible interferences from polymer combustion products are not routinely evaluated. The NASA White Sands Test Facility (WSTF) has developed a test system that provides atmospheres containing predetermined quantities of target gases combined with the coincidental combustion products of common spacecraft materials. The target gases are quantitated in real time by infrared (IR) spectroscopy and verified by grab samples. The sensor responses are recorded in real time and are compared to the IR and validation analyses. Target gases such as carbon monoxide, hydrogen cyanide, hydrogen chloride, and hydrogen fluoride can be generated by the combustion of poly(vinyl chloride), polyimide-fluoropolymer wire insulation, polyurethane foam, or electronic circuit board materials. The kinetics and product identifications for the combustion of the various materials were determined by thermogravimetric-IR spectroscopic studies. These data were then scaled to provide the required levels of target gases in the sensor evaluation system. Multisensor toxic gas monitors from two manufacturers were evaluated using this system. In general, the sensor responses satisfactorily tracked the real-time concentrations of toxic gases in a dynamic mixture. Interferences from a number of organic combustion products including acetaldehyde and bisphenol-A were minimal. Hydrogen bromide in the products of circuit board combustion registered as hydrogen chloride. The use of actual polymer combustion atmospheres for the evaluation of sensors can provide additional confidence in the reliability of the sensor response.

  10. A kinetics study for reaction process of Rn daughter and atmospheric trace gas using alpha track detection

    International Nuclear Information System (INIS)

    A number of investigators have reported formation of radiolytic ultrafine particles produced by the interaction of ionizing radiation with atmospheric trace gases. Previous studies have suggested that a very high localized concentration of the hydroxyl radical produced by the radiolysis of water can react with atmospheric trace gases such as SO2 and produce lower vapor pressure compounds that can subsequently nucleate. To determine the trace gas and water vapor concentration dependence of the active, positively charged, first decay product of radon (Po-218), a well-controlled radon chamber was used in this research. The mobility spectrum of the decay products in the range of 0.07-5.0 cm2/V.sec from the radon chamber was measured using alpha track detector installed inside a specially-designed electrostatic spectrometer. Measurements were taken for different concentrations (0.5 ppm to 5 ppm) of SO2 in purified, compressed air. A kinetics study following the clustering of SO2 around the PoOx + ion in an excess of SO2 for interpretation of the reaction processes was performed

  11. Non-thermal production and escape of OH from the upper atmosphere of Mars

    CERN Document Server

    Gacesa, Marko; Kharchenko, Vasili

    2016-01-01

    We present a theoretical analysis of formation and kinetics of hot OH molecules in the upper atmosphere of Mars produced in reactions of thermal molecular hydrogen and energetic oxygen atoms. Two major sources of energetic O considered are the photochemical production, via dissociative recombination of O$_{2}^{+}$ ions, and energizing collisions with fast atoms produced by the precipitating Solar Wind (SW) ions, mostly H$^+$ and He$^{2+}$, and energetic neutral atoms (ENAs) originating in the charge-exchange collisions between the SW ions and atmospheric gases. Energizing collisions of O with atmospheric secondary hot atoms, induced by precipitating SW ions and ENAs, are also included in our consideration. The non-thermal reaction O + H$_2(v,j) \\rightarrow$ H + OH$(v',j')$ is described using recent quantum-mechanical state-to-state cross sections, which allow us to predict non-equilibrium distributions of excited rotational and vibrational states $(v',j')$ of OH and expected emission spectra. A fraction of pr...

  12. Atmospheric chemistry of CF3C(O)O2 radicals. Kinetics of their reaction with NO2 and kinetics of the thermal decomposition of the product CF3C(O)O2NO2

    DEFF Research Database (Denmark)

    Wallington, T.J.; Sehested, J.; Nielsen, O.J.

    1994-01-01

    A pulse radiolysis technique has been used to measure a rate constant of (6.6 +/- 1.3) x 10(-12) cm3 molecule-1 s-1 for the association reaction between CF3C(O)O2 radicals and NO2 at 295 K and one atmosphere total pressure of SF6 diluent. A FTIR/smog chamber system was used to study the thermal...... decomposition CF3C(O)O2NO2. The rate of decomposition of CF3C(O)O2NO2 was independent of the total pressure of N2 diluent over the range 100-700 Torr and was fit by the expression k-1 = (1.9(-1.5)+7.6) x 10(16) exp[(-14000 +/- 480)/T] s-1. Implications for the atmospheric chemistry of CFC replacements are...

  13. Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction

    Directory of Open Access Journals (Sweden)

    Thomas Zeuch

    2013-11-01

    Full Text Available Photochemically driven reactions involving unsaturated radicals produce a thick global layer of organic haze on Titan, Saturn’s largest moon. The allyl radical self-reaction is an example for this type of chemistry and was examined at room temperature from an experimental and kinetic modelling perspective. The experiments were performed in a static reactor with a volume of 5 L under wall free conditions. The allyl radicals were produced from laser flash photolysis of three different precursors allyl bromide (C3H5Br, allyl chloride (C3H5Cl, and 1,5-hexadiene (CH2CH(CH22CHCH2 at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re- combination pathway C3H5+C3H5 → C6H10 we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C3H5Br. A kinetic analysis indicates that the end product formation is influenced by specific reaction kinetics of photochemically activated allyl radicals. Above 10 mbar the (re- combination pathway becomes dominant. These findings exemplify the specificities of reaction kinetics involving chemically activated species, which for certain conditions cannot be simply deduced from combustion kinetics or atmospheric chemistry on Earth.

  14. Syngas Production from Propane Using Atmospheric Non-thermal Plasma

    CERN Document Server

    Ouni, Fakhreddine; Cormier, Jean Marie; 10.1007/s11090-009-9166-2

    2009-01-01

    Propane steam reforming using a sliding discharge reactor was investigated under atmospheric pressure and low temperature (420 K). Non-thermal plasma steam reforming proceeded efficiently and hydrogen was formed as a main product (H2 concentration up to 50%). By-products (C2-hydrocarbons, methane, carbon dioxide) were measured with concentrations lower than 6%. The mean electrical power injected in the discharge is less than 2 kW. The process efficiency is described in terms of propane conversion rate, steam reforming and cracking selectivity, as well as by-products production. Chemical processes modelling based on classical thermodynamic equilibrium reactor is also proposed. Calculated data fit quiet well experimental results and indicate that the improvement of C3H8 conversion and then H2 production can be achieved by increasing the gas fraction through the discharge. By improving the reactor design, the non-thermal plasma has a potential for being an effective way for supplying hydrogen or synthesis gas.

  15. On the effect of nuclear interactions in neutrino reactions with oxygen targets and its role in atmospheric neutrino anomaly

    International Nuclear Information System (INIS)

    Atmospheric neutrinos are produced by interactions of the cosmic rays with the atmosphere's nuclei. The observed ratio of muonic to electronic neutrinos is smaller than the theoretical one (up to a factor 2), this is the so-called atmospheric anomaly. This anomaly could be linked to that observed in the solar neutrino experiments. The aim of this work is to evaluate the effects of nuclear correlations upon the interaction of the atmospheric neutrinos with the oxygen nuclei of the water Cherenkov detectors. The products of these interactions are detected and identified thanks to the light ring the produce. The events are classified according to the number of produced rings which is computed from the neutrino-oxygen event rates in each exclusive reaction channel. The interpretation of the experimental results has been up to now limited to the quasi-elastic nucleon and Δ channels but other reaction channels exist which can lead to identification problems. A special role is played by the non-pionic decay channels of the Δ resonance which induce single ring events that have not been considered so far. To calculate them we adopted the nuclear response formalism and started with a semi-classical approximation. This allowed us to take into account the nuclear correlations by solving exactly the RPA equations in the ring approximation. It was found that these correlations strongly modify the inclusive and exclusive neutrino-oxygen cross sections and absolute interaction rates while the ratio of the interaction rates μ/e is not very much affected. The analysis in the exclusive channels leads to the result that the number of pions predicted in the simulations is overestimated. In conclusion, this work has shown the importance of the nuclear correlations in the neutrino-oxygen interaction and its impact on the atmospheric neutrino anomaly. It goes beyond the usual quasi-elastic approximations and can be moreover extended to other target nuclei, such as iron, used in earlier

  16. Atmospheric Oxidation Mechanism and Kinetic Studies for OH and NO3 Radical-Initiated Reaction of Methyl Methacrylate

    Directory of Open Access Journals (Sweden)

    Rui Gao

    2014-03-01

    Full Text Available The mechanism for OH and NO3 radical-initiated oxidation reactions of methyl methacrylate (MMA was investigated by using density functional theory (DFT molecular orbital theory. Geometrical parameters of the reactants, intermediates, transition states, and products were fully optimized at the B3LYP/6-31G(d,p level. Detailed oxidation pathways were presented and discussed. The rate constants were deduced by the canonical variational transition-state (CVT theory with the small-curvature tunneling (SCT correction and the multichannel Rice-Ramspergere-Kassele-Marcus (RRKM theory, based on the potential energy surface profiles over the general atmospheric temperature range of 180–370 K. The calculated results were in reasonable agreement with experimental measurement.

  17. Yields of O2(b 1 Sigma g +) from reactions of HO2. [in planetary atmospheres

    Science.gov (United States)

    Keyser, L. F.; Choo, K. Y.; Leu, M. T.

    1985-01-01

    The production of O2(b 1 Sigma g +) has been monitored for several reactions of the HO2 radical at 300 K using a discharge-flow apparatus with resonance fluorescence and chemiluminescence detection. In all cases, the resulting quantum efficiencies were found to be less than 0.03. O2(b) was observed when F atoms were added to H2O2 in the gas phase. The signal strengths of O2(b) were proportional to initial concentrations of HO2 formed by the F + H2O2 reaction. Observed /O2(b)/, /HO2/, and /OH/ vs /F/0 were analyzed using a simple three-step mechanism and a more complete computer simulation with 22 reaction steps. The results indicate that the F + HO2 reaction yields O2(b) with an efficiency of (3.6 + or - 1.4) x 10 to the -3rd. Yields from the O + OH2 reaction were less than 0.02, indicating that this reaction cannot be a major source of the O2(b) emission observed in the earth's nightglow.

  18. Dual Position Sensitive MWPC for tracking reaction products at VAMOS++

    Science.gov (United States)

    Vandebrouck, M.; Lemasson, A.; Rejmund, M.; Fremont, G.; Pancin, J.; Navin, A.; Michelagnoli, C.; Goupil, J.; Spitaels, C.; Jacquot, B.

    2016-03-01

    The characteristics and performance of a Dual Position Sensitive Multi-Wire Proportional Counter (DPS-MWPC) used to measure the scattering angle, the interaction position on the target and the velocity of reaction products detected in the VAMOS++ magnetic spectrometer, are reported. The detector consists of a pair of position sensitive low pressure MWPCs and provides both fast timing signals, along with the two-dimensional position coordinates required to define the trajectory of the reaction products. A time-of-flight resolution of 305(11) ps (FWHM) was measured. The measured resolutions (FWHM) were 2.5(3) mrad and 560(70) μm for the scattering angle and the interaction point at the target respectively. The subsequent improvement of the Doppler correction of the energy of the γ-rays, detected in the γ-ray tracking array AGATA in coincidence with isotopically identified ions in VAMOS++, is also discussed.

  19. Dual Position Sensitive MWPC for tracking reaction products at VAMOS++

    CERN Document Server

    Vandebrouck, Marine; Rejmund, Maurycy; Fremont, Georges; Pancin, Julien; Navin, Alahari; Michelagnoli, Caterina; Goupil, Johan; Spitaels, Charles; Jacquot, Bertrand

    2015-01-01

    The characteristics and performance of a Dual Position Sensitive Multi-Wire Proportional Counter (DPS-MWPC) used to measure the scattering angle, interaction position on the target and the velocity of reaction products, detected in the VAMOS++ magnetic spectrometer, are reported. The detector consists of a pair of position sensitive low pressure MWPCs and provides both fast timing signals, along with the two-dimensional position coordinates required to define the trajectory of the reaction products. A time-of-flight resolution of 305(11) ps (FWHM) was measured. The measured resolutions (FWHM) were 2.5(3) mrad and 560(70) {\\mu}m for the scattering angle and the interaction point at the target respectively. The subsequent improvement of the Doppler correction of the energy of the gamma-rays, detected in the gamma-ray tracking array AGATA in coincidence with isotopically identified ions in VAMOS++, is also discussed.

  20. Evaluation of Production Reactions for Medically Important Positron Emitters

    International Nuclear Information System (INIS)

    Research activities of direct relevance to the CRP are based on the proposed evaluation of a range of medically important positron emitters. The production and assessment of excitation functions for various novel positron emitters has been recommended for investigation and quantification. Hence, the research group at Lahore has developed an evaluation methodology for charged-particle induced reactions. The main steps of the adopted procedure are listed

  1. Reaction products of aquatic humic substances with chlorine.

    OpenAIRE

    Johnson, J D; Christman, R F; Norwood, D L; Millington, D S

    1982-01-01

    A major concern of the chlorination of aquatic humic materials is the ubiquitous production of trihalomethanes. A large number of other chlorinated organic compounds, however, have been shown to be formed by chlorine's reaction with humic substances. In this study, humic material was concentrated from a coastal North Carolina lake and chlorinated at a chlorine to carbon mole ratio of 1.5 at pH 12. A high pH was necessary for complete dissolution of the humic material and for production of ade...

  2. Distribution of products in the reaction 20Ne + Al

    International Nuclear Information System (INIS)

    The measurement and preliminary analysis of the distribution of products with Z between 2 and 21 and A between 3 and 43 from 118- and 167-MeV reactions of 20Ne with Al are reported. Experimental conditions were adequate to allow resolution of individual isotopes over this entire range, and measurements were made at several angles for each bombarding energy. Measured relative cross sections of the heavier products were compared with predictions of a statistical-model evaporation calculation. The overall agreement between experiment and theory was rather good; however, certain discrepancies between calculation and experiment for low Z and A at 167 MeV may be troublesome. 3 figures

  3. Influence of transesterification reaction temperature on biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Pighinelli, Anna Leticia Montenegro Turtelli; Zorzeto, Thais Queiroz; Park, Kil Jin [Universidade Estadual de Campinas (FEAGRI/UNICAMP), SP (Brazil). Fac. de Engenharia Agricola], E-mail: annalets@agr.unicamp.br; Bevilaqua, Gabriela [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2008-07-01

    Brazilian government policy has authorized the introduction of biodiesel into the national energy matrix, law no.11.097 of January 13th, 2005. It is necessary, like any new product, to invest in research which is able to cover its entire production chain (planting of oilseeds, vegetable oils extraction and chemical reactions), providing data and relevant information in order to optimize the process and solve critical issues. The objective of this work was to study the effects of temperature on crude sunflower transesterification reaction with ethanol. A central composite experimental design with five variation levels (25 deg, 32 deg, 47.5 deg, 64 deg and 70 deg C) was used and response surface methodology applied for the data analysis. The statistical analysis of the results showed that the production suffered the influence of temperature (linear and quadratic effects) and reaction time (linear and quadratic). The generated models did not show significant regression. The model generated was not well suited to the experimental data and the value of the coefficient of determination (R{sup 2}=0.52) was low. Consequently it was not possible to build the response surface. (author)

  4. Multi-Strangeness Production in Hadron Induced Reactions

    CERN Document Server

    Gaitanos, T; Lalazissis, G A; Lenske, H

    2016-01-01

    We discuss in detail the formation and propagation of multi-strangeness particles in reactions induced by hadron beams relevant for the forthcoming experiments at FAIR. We focus the discussion on the production of the decuplett-particle $\\Omega$ and study for the first time the production and propagation mechanism of this heavy hyperon inside hadronic environments. The transport calculations show the possibility of $\\Omega$-production in the forthcoming \\panda-experiment, which can be achieved with measurable probabilities using high-energy secondary $\\Xi$-beams. We predict cross sections for $\\Omega$-production. The theoretical results are important in understanding the hyperon-nucleon and, in particular, the hyperon-hyperon interactions also in the high-strangeness sector. We emphasize the importance of our studies for the research plans at FAIR.

  5. Sub-60 deg. C atmospheric helium-water plasma jets: modes, electron heating and downstream reaction chemistry

    International Nuclear Information System (INIS)

    For plasma treatment of many heat-labile materials (e.g. living tissues) that either are moist or contain a surface layer of liquid, it is desirable that the gas plasma is generated at atmospheric pressure for process convenience and with a gas temperature ideally no more than 60 deg. C for mitigating permanent damage to the integrity of the test material. This implies that the liquid-containing plasma needs to be of low dissipated electrical energy and that plasma treatment should be based largely on non-equilibrium reaction chemistry. In this paper, a class of sub-60 deg. C atmospheric helium-water plasma jets is studied in terms of their main physiochemical properties. It is shown that there are five distinct modes appearing in the sequence of, with increasing voltage, the first chaotic mode, the plasma bullet mode, the second chaotic mode, the abnormal glow mode and the non-thermal arc mode. Its chaotic modes may be sustained over a wide range of water vapour concentrations (0-2500 ppm). Compared with other liquid-containing plasmas, the He-H2O plasma jet operated below its non-thermal arc mode has several distinct advantages, namely very low energy consumption (2-10 μJ per pulse), sub-60 deg. C gas temperature, electron-modulated production of He, N2, N2+, O*, H and OH(A-X), and low ozone production (0.1-0.4 ppm). These results provide a first attempt at the landscape of the physiochemical characteristics in atmospheric He-H2O plasma jets.

  6. A kinetic study of the reaction of ozone with ethylene in a smog chamber under atmospheric conditions

    Institute of Scientific and Technical Information of China (English)

    XU Yongfu; JIA Long; GE Maofa; DU Lin; WANG Gengchen; WANG Dianxun

    2006-01-01

    Ozone is one of the key species in the processes of atmospheric chemistry, which can be taken as an indicator of oxidation capacity in the troposphere, The reaction of ozone with reactive gases is an important process in the troposphere. Experimental simulation equipment of smog chamber for atmospheric reactions is used to study the reaction of ozone with ethylene in real atmospheric environment with ozone concentrations of 100-200 ppb. The concentrations of ozone and ethylene were monitored during the reaction with the combination of Model 49C-O3 Analyzer and GC-FID. A rate constant of 1.01×10-18 (cm3.mol-1.s-1) was obtained at 286.5 K,under condition of which the half-life of ozone was 88 min. The results obtained from our experiments are in excellent agreement with those reported previously by other researchers under extremely Iow pressure in terms of matrix-isolation technology. This demonstrates that our equipment of smog chamber for atmospheric reactions is reliable, which can be used for further research of the processes of atmospheric reactions.

  7. Common inorganic ions are efficient catalysts for organic reactions in atmospheric aerosols and other natural environments

    Science.gov (United States)

    Nozière, B.; Dziedzic, P.; Córdova, A.

    2009-01-01

    In this work, inorganic ammonium ions, NH4+, and carbonate ions, CO32-, are reported for the first time as catalysts for organic reactions in atmospheric aerosols and other natural environments at the Earth's surface. These reactions include the formation of C-C and C-O bonds by aldol condensation and acetal formation, and reveal a new aspect of the interactions between organic and inorganic materials in natural environments. The catalytic properties of inorganic ammonium ions, in particular, were not previously known in chemistry. The reactions were found to be as fast in tropospheric ammonium sulfate composition as in concentrated sulfuric acid. The ubiquitous presence and large concentrations of ammonium ions in tropospheric aerosols would make of ammonium catalysis a main consumption pathway for organic compounds in these aerosols, while acid catalysis would have a minor contribution. In particular, ammonium catalysis would account quantitatively for the aging of carbonyl compounds into secondary ''fulvic'' compounds in tropospheric aerosols, a transformation affecting the optical properties of these aerosols. In general, ammonium catalysis is likely to be responsible for many observations previously attributed to acid catalysis in the troposphere.

  8. Common inorganic ions are efficient catalysts for organic reactions in atmospheric aerosols and other natural environments

    Directory of Open Access Journals (Sweden)

    B. Nozière

    2009-01-01

    Full Text Available In this work, inorganic ammonium ions, NH4+, and carbonate ions, CO32−, are reported for the first time as catalysts for organic reactions in atmospheric aerosols and other natural environments at the Earth's surface. These reactions include the formation of C–C and C–O bonds by aldol condensation and acetal formation, and reveal a new aspect of the interactions between organic and inorganic materials in natural environments. The catalytic properties of inorganic ammonium ions, in particular, were not previously known in chemistry. The reactions were found to be as fast in tropospheric ammonium sulfate composition as in concentrated sulfuric acid. The ubiquitous presence and large concentrations of ammonium ions in tropospheric aerosols would make of ammonium catalysis a main consumption pathway for organic compounds in these aerosols, while acid catalysis would have a minor contribution. In particular, ammonium catalysis would account quantitatively for the aging of carbonyl compounds into secondary ''fulvic'' compounds in tropospheric aerosols, a transformation affecting the optical properties of these aerosols. In general, ammonium catalysis is likely to be responsible for many observations previously attributed to acid catalysis in the troposphere.

  9. Influences of Reaction Parameters on the Product of a Geothermite Reaction: A Multi-Component Oxidation-Reduction Reaction Study

    OpenAIRE

    Faierson, Eric J.

    2009-01-01

    This study investigated an oxidation-reduction reaction involving a mixture of minerals, glass, and aluminum that exhibited thermite-type reaction behavior. Thermite reactions are a class of Self-propagating High-temperature Synthesis (SHS) reactions. Chemical reactions between raw minerals and a reducing agent, which exhibit thermite-type reaction behavior, are termed geothermite reactions by the author. Geothermite reactions have the potential for use in In-Situ Resource Utilization (ISRU...

  10. Theoretical study on the mechanism of CH3NH2 and O3 atmospheric reaction

    Indian Academy of Sciences (India)

    Samira Valehi; Morteza Vahedpour

    2014-07-01

    Reaction pathways of methylamine with ozone on the singlet potential energy profile have been investigated at the RB3LYP/6-311++G (3df-3pd) computational level. Calculated results reveal that six kinds of products P1 (CH3NO + H2O2), P2 (CH3NH + OH + O2), P3 (NH2CH + HO2+ OH), P4 (CH2NH + H2O +O2), P5 (NH2CH2OH + O2), P6 (NH3+ CH2O +O2) are obtained through variety of transformation of one reactant complex C1. Cleavage and formation of the chemical bonds in the reaction pathways have been discussed using the structural parameters. Based on the calculations, the title reaction leads to NH3+ CH2O + O2 as thermodynamic adducts in an exothermic process by −76.28 kcal/mol in heat realizing and spontaneous reaction by −86.71 kcal/mol in standard Gibbs free energy. From a kinetic viewpoint, the production of CH3NH + OH + O2 adducts with one transition state is the most favoured path.

  11. Mass balance of reaction products from irradiated TCE vapor

    International Nuclear Information System (INIS)

    Trichloroethylene (TCE) vapor, at a concentration of 3,000 ppmv in synthetic air, was sealed in Tedlar bags and irradiated with a 3.7 MeV electron beam. Bags of dry vapor and vapor at 90% relative humidity were irradiated. Doses up to 11 megarads (11 MR) were applied. Each bag was chemically analyzed for reaction products and a mass balance of the chlorine and carbon was obtained within the 11 MR dose range. The results of these radiolysis experiments and chemical analysis show that, given the proper treatment, the TCE concentration is reduced to below detection limit and the reaction products of the organic carbon and chlorine are carbon monoxide (CO), carbon dioxide (CO2), chlorine gas (Cl2) and hydrochloric acid (HCl). No detectable amounts of dichloroacetyl chloride (DCAC) or phosgene (PG) remained in the sample after proper treatment. DCAC and PG were found only as intermediary oxidation products of the TCE. High energy ionizing radiation, as electron beams and bremsstrahlung, is a new treatment technology for destroying toxic compounds and hazardous wastes. A demonstration of complete destruction of organic products, using this treatment at standard temperature and pressure, is expected to help implement the use of this technology

  12. Temperature- and pH-dependent aqueous-phase kinetics of the reactions of glyoxal and methylglyoxal with atmospheric amines and ammonium sulfate

    Science.gov (United States)

    Sedehi, Nahzaneen; Takano, Hiromi; Blasic, Vanessa A.; Sullivan, Kristin A.; De Haan, David O.

    2013-10-01

    Reactions of glyoxal (Glx) and methylglyoxal (MG) with primary amines and ammonium salts may produce brown carbon and N-containing oligomers in aqueous aerosol. 1H NMR monitoring of reactant losses and product appearance in bulk aqueous reactions were used to derive rate constants and quantify competing reaction pathways as a function of pH and temperature. Glx + ammonium sulfate (AS) and amine reactions generate products containing C-N bonds, with rates depending directly on pH: rate = (70 ± 60) M-1 s-1fAld [Glx]totfAm [Am]tot, where fAld is the fraction of aldehyde with a dehydrated aldehyde functional group, and fAm is the fraction of amine or ammonia that is deprotonated at a given pH. MG + amine reactions generate mostly aldol condensation products and exhibit less pH dependence: rate = 10[(0.36 ± 0.06) × pH - (3.6 ± 0.3)] M-1 s-1fAld [MG]tot [Am]tot. Aldehyde + AS reactions are less temperature-dependent (Ea = 18 ± 8 kJ mol-1) than corresponding amine reactions (Ea = 50 ± 11 kJ mol-1). Using aerosol concentrations of [OH] = 10-12 M, [amine]tot = [AS] = 0.1 M, fGlx = 0.046 and fMG = 0.09, we estimate that OH radical reactions are normally the major aerosol-phase sink for both dicarbonyl compounds. However, reactions with AS and amines together can account for up to 12 and 45% of daytime aerosol-phase glyoxal and methylglyoxal reactivity, respectively, in marine aerosol at pH 5.5. Reactions with AS and amines become less important in acidic or non-marine aerosol, but may still be significant atmospheric sources of brown carbon, imidazoles, and nitrogen-containing oligomers.

  13. Glow-Discharge Production of Oxygen from the Martian Atmosphere

    Science.gov (United States)

    Hughes, Caleb; Outlaw, Ronald

    One of the most crucial aspects of any mission to Mars is a continual supply of oxygen for astronaut respiration on site. The most popular approach to this problem favors in-situ oxygen production on Mars, utilizing the CO2 Martian atmosphere. However, this requires a large energy budget. NASA's current plans for Mars include sending a system called MOXIE, which produces oxygen through solid oxide electrolysis at high temperatures. An alternative approach utilizes the 6 Torr Martian atmosphere to provide a continual source of oxygen by breaking down the molecule into CO and O using a glow-discharge. After dissociation, a thin film Agmembrane uniquely permeates the atomic oxygen which then recombines to O2 on the downstream side, where it is subsequently stored. By taking advantage of recent advances in thin film technology to reduce the thickness of the film to many orders of magnitude less than used in the initial study, a corresponding increase in O2 flux can be realized. The Ag thin film requires the support of a porous ceramic substructure. With this system, it is shown that this method produces a viable energy efficient alternative to MOXIE.

  14. VIIRS Atmospheric Products in the Community Satellite Processing Package (CSPP)

    Science.gov (United States)

    Cureton, G. P.; Gumley, L.; Mindock, S.; Martin, G.; Garcia, R. K.; Strabala, K.

    2012-12-01

    The Cooperative Institute for Meteorological Satellite Studies (CIMSS) has a long history of supporting the Direct Broadcast (DB) community for various sensors, recently with the International MODIS/AIRS Processing Package (IMAPP) for the NASA EOS polar orbiters Terra and Aqua. CIMSS has continued this effort into the NPP/JPSS (previously NPOESS) era with the development of the Community Satellite Processing Package (CSPP), supporting the VIIRS, CrIS and ATMS sensors on the Suomi National Polar-orbiting Partnership (Suomi NPP) spacecraft. In time it is intended that CSPP will support GOES-R, JPSS and other geostationary and polar orbiting platforms. Here we focus on the implementation and usage of the Visible Infrared Imaging Radiometer Suite (VIIRS) atmospheric product sub-packages within CSPP, which are based on the Interface Data Processing Segment (IDPS) code as implemented by Raytheon in the Algorithm Development Library (ADL). The VIIRS atmospheric algorithms available in CSPP include the Cloud Mask, Active Fires, Cloud Optical Properties, Cloud Top Parameters, and the Aerosol Optical Thickness algorithms. Each ADL sub-package consists of a binary executable and a series of configuration XML files. A series of python scripts handle ancillary data retrieval and preparation for ingest into ADL, manage algorithm execution, and provide a variety of execution options which are of utility in operational and algorithm development settings. Examples of these options, applied to operational and direct-broadcast VIIRS SDR data, are described.

  15. Meson production and Nuclear fragmentation of nucleus in the atmosphere

    International Nuclear Information System (INIS)

    Propagation of the primary and secondary cosmic ray in the atmosphere is calculated analitically. Two different cases of primary cosmic ray composition are used; the first case concerns the mixed composition of very heavy, heavy, middle, light nuclei and nucleons; and the second case considers only nucleons in the primary cosmic ray flux. The mechanism of multiple meson production is formulated according to the wounded nucleon model for nucleus-nucleus interaction and the scaling model for nucleon-nucleon interaction. The mechanism of nuclei fragmentation is formulated according to the experimental values of the fragmentation parameters at low energy. The calculated results of the electromagnetic flux are compared with the results of mountain experiments with large scale emulsion chamber and experimental data at airplane altitude. From these comparisons the calculation of electromagnetic flux altitude variation of the first case gives the best fit with experimental data than the second case. (author)

  16. Nucleation and aerosol processing in atmospheric pressure electrical discharges: powders production, coatings and filtration

    International Nuclear Information System (INIS)

    This review addresses the production of nano-particles and the processing of particles injected in atmospheric pressure electrical discharges (APED). The mechanisms of formation and the evolution of particles suspended in gases are first presented, with numerical and experimental facilities. Different APED and related properties are then introduced for dc corona, streamer and spark filamentary discharges (FD), as well as for ac filamentary and homogeneous dielectric barrier discharges (DBD). Two mechanisms of particle production are depicted in APED: when FD interact with the surface of electrodes or dielectrics and when filamentary and homogeneous DBD induce reactions with gaseous precursors in volume. In both cases, condensable gaseous species are produced, leading to nano-sized particles by physical and chemical routes of nucleation. The evolution of the so-formed nano-particles, i.e. the growth by coagulation/condensation, the charging and the collection are detailed for each APED, with respect to fine powders production and thin films deposition. Finally, when particles are injected in APED, they undergo interfacial processes. Non-thermal plasmas charge particles for electro-collection and trigger heterogeneous chemical reactions for organic and inorganic films deposition. Heat exchanges in thermal plasmas enable powder purification, shaping, melting for hard coatings and fine powders production by reactive evaporation. (topical review)

  17. TOPICAL REVIEW: Nucleation and aerosol processing in atmospheric pressure electrical discharges: powders production, coatings and filtration

    Science.gov (United States)

    Borra, Jean-Pascal

    2006-01-01

    This review addresses the production of nano-particles and the processing of particles injected in atmospheric pressure electrical discharges (APED). The mechanisms of formation and the evolution of particles suspended in gases are first presented, with numerical and experimental facilities. Different APED and related properties are then introduced for dc corona, streamer and spark filamentary discharges (FD), as well as for ac filamentary and homogeneous dielectric barrier discharges (DBD). Two mechanisms of particle production are depicted in APED: when FD interact with the surface of electrodes or dielectrics and when filamentary and homogeneous DBD induce reactions with gaseous precursors in volume. In both cases, condensable gaseous species are produced, leading to nano-sized particles by physical and chemical routes of nucleation. The evolution of the so-formed nano-particles, i.e. the growth by coagulation/condensation, the charging and the collection are detailed for each APED, with respect to fine powders production and thin films deposition. Finally, when particles are injected in APED, they undergo interfacial processes. Non-thermal plasmas charge particles for electro-collection and trigger heterogeneous chemical reactions for organic and inorganic films deposition. Heat exchanges in thermal plasmas enable powder purification, shaping, melting for hard coatings and fine powders production by reactive evaporation.

  18. Production mechanism of superheavy nuclei in massive fusion reactions

    Institute of Scientific and Technical Information of China (English)

    FENG Zhao-Qing; JIN Gen-Ming; LI Jun-Qing; Werner Scheid

    2009-01-01

    Within the concept of the dinuclear system (DNS), a dynamical model is proposed for describing the formation of superheavy nuclei in complete fusion reactions by incorporating the coupling of the relative motion to the nucleon transfer process. The capture of two heavy colliding nuclei, the formation of the compound nucleus and the de-excitation process are calculated by using an empirical coupled channel model, solving a set of microscopically derived master equations numerically and applying statistical theory, respectively.Fusion-fission reactions and evaporation residue excitation functions of synthesizing superheavy nuclei (SHN) are investigated systematically and compared them with available experimental data. The possible factors that affecting the production cross sections of SHN are discussed in this workshop.

  19. Coherent pion production in heavy ion charge exchange reactions

    International Nuclear Information System (INIS)

    We report the first observation of coherent pion production induced by a heavy ion charge exchange reaction. The (12C,12N) reaction [D. Bachelier et al., Phys. Lett. B 172 (1986) 23; M. Roy-Stephan et al., Nucl. Phys. A 488 (1988) 178] at 1.1 GeV/nucleon has been used to shine negative (off-shell) pions on nuclei and observe (on-shell) pions, leaving the target nucleus in its ground state. The experiment was performed at the Laboratoire National Saturne with the SPES4-π setup [Laurent Farhi PHD thesis IPNO-T97-12, Universite d'Orsay, 1997; Rasmus Dahl Ph.D., Niels Bohr Institutet, Copenhagen (1999)

  20. 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

    Science.gov (United States)

    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

  1. Atmospheric pressure photoionization mass spectrometry as a tool for the investigation of the hydrolysis reaction mechanisms of phosphite antioxidants

    Science.gov (United States)

    Papanastasiou, M.; McMahon, A. W.; Allen, N. S.; Johnson, B. W.; Keck-Antoine, K.; Santos, L.; Neumann, M. G.

    2008-08-01

    The hydrolysis reaction mechanism of phosphite antioxidants is investigated by liquid chromatography-mass spectrometry (LC/MS). The phosphites were chosen because they differed in chemical structure and phosphorus content. Dopant assisted-atmospheric pressure photoionization (DA-APPI) is chosen as the ion source for the ionization of the compounds. In our previous work, DA-APPI was shown to offer an attractive alternative to atmospheric pressure chemical ionization (APCI) since it provided background-ion free mass spectra and higher sensitivity [M. Papanastasiou, et al., Polymer Degradation and Stability 91 (11) (2006) 2675-2682]. In positive ion mode, the molecules are generally detected in their protonated form. In negative ion mode, the phosphites are unstable and only fragment ions are observed; these however, are characteristic of each phosphite and may be used for the identification of the analytes in complex mixtures. The analytes under investigation are exposed to accelerated humid ageing conditions and their hydrolytic pathway and stability is investigated. Different substituents around the phosphorus atom are shown to have a significant effect on the stability of the phosphites, with phenol substituents producing very hydrolytically stable structures. Alkanox P24 and PEP-36 follow a similar hydrolytic pathway via the scission of the first and then the second POphenol bonds, eventually leading to the formation of phenol, phosphorous acid and pentaerythritol as end products. HP-10 exhibits a rather different structure and the products detected suggest scission of either the POhydrocarbon or one of the POphenol bonds. A phenomenon similar to that of autocatalysis is observed for all phosphites and is attributed to the formation of dialkyl phosphites as intermediate products.

  2. Products of the OH radical-initiated reactions of 2- and 3-hexyl nitrate

    Science.gov (United States)

    Aschmann, Sara M.; Arey, Janet; Atkinson, Roger

    2012-01-01

    Products of the gas-phase reaction of OH radicals with 2-hexyl nitrate (containing 13% 3-hexyl nitrate) have been investigated by gas chromatography with mass spectral and flame ionization detection, and by direct air sampling atmospheric pressure ionization tandem mass spectrometry. The products identified and quantified from 2-hexyl nitrate were: 2-hexanone (8.6 ± 1.3%), propanal (3.4 ± 0.8%), butanal (2.3 ± 0.6%) and 5-hydroxy-2-hexanone (25%), where the molar yields are given in parentheses. 3-Hexanone was observed from the 3-hexyl nitrate reaction, with a molar formation yield of 9.5 ± 2.1%. Organic nitrates of molecular weight 133, 161, 177 and 208 were also observed, and these are attributed to C 4-carbonyl nitrate(s), C 6-carbonyl-nitrates, C 6-hydroxycarbonyl-nitrates and C 6-dinitrates, respectively, and are expected to account for all or most of the non-quantified reaction products from OH + 2- and 3-hexyl nitrate. 5-Hydroxy-2-hexanone formation indicates that the CH 3CH(ONO 2)CH 2CH 2CH(O rad )CH 3 alkoxy radical dominantly reacts by isomerization.

  3. Two-pion production in photon-induced reactions

    Indian Academy of Sciences (India)

    S Schadmand

    2006-05-01

    Differences in the photoproduction of mesons on the free proton and on nuclei are expected to reveal changes in the properties of hadrons. Inclusive studies of nuclear photoabsorption have provided evidence of medium modifications. However, the results have not been explained in a model independent way. A deeper understanding of the situation is anticipated from a detailed experimental study of meson photoproduction from nuclei in exclusive reactions. In the energy regime above the (1232) resonance, the dominant double pion production channels are of particular interest. Double pion photoproduction from nuclei is also used to investigate the in-medium modification of meson–meson interactions.

  4. Solar Thermochemical Hydrogen Production via Terbium Oxide Based Redox Reactions

    OpenAIRE

    Rahul Bhosale; Anand Kumar; Fares AlMomani

    2016-01-01

    The computational thermodynamic modeling of the terbium oxide based two-step solar thermochemical water splitting (Tb-WS) cycle is reported. The 1st step of the Tb-WS cycle involves thermal reduction of TbO2 into Tb and O2, whereas the 2nd step corresponds to the production of H2 through Tb oxidation by water splitting reaction. Equilibrium compositions associated with the thermal reduction and water splitting steps were determined via HSC simulations. Influence of oxygen partial pressure in ...

  5. UF6- production from surface reactions of uranium and fluorine

    International Nuclear Information System (INIS)

    The production of UF6- by reaction of a collimated stream of fluorine gas with a resistively heated uranium wire was studied at temperatures from 870 to 10200C and pressures less than 10-3 torr. At these temperatures below the uranium melting point, the formation of UF3 intermediate on the uranium surface resulted in low UF6- yields. The kinetic energy of the UF6- ion was on the order of thermal energies. The work function of uranium was measured to be 4.20 +- 0.14 eV

  6. Chemical kinetic studies of atmospheric reactions using tunable diode laser spectroscopy

    Science.gov (United States)

    Worsnop, Douglas R.; Nelson, David D.; Zahniser, Mark S.

    1993-01-01

    IR absorption using tunable diode laser spectroscopy provides a sensitive and quantitative detection method for laboratory kinetic studies of atmospheric trace gases. Improvements in multipass cell design, real time signal processing, and computer controlled data acquisition and analysis have extended the applicability of the technique. We have developed several optical systems using off-axis resonator mirror designs which maximize path length while minimizing both the sample volume and the interference fringes inherent in conventional 'White' cells. Computerized signal processing using rapid scan (300 kHz), sweep integration with 100 percent duty cycle allows substantial noise reduction while retaining the advantages of using direct absorption for absolute absorbance measurements and simultaneous detection of multiple species. Peak heights and areas are determined by curve fitting using nonlinear least square methods. We have applied these techniques to measurements of: (1) heterogeneous uptake chemistry of atmospheric trace gases (HCl, H2O2, and N2O5) on aqueous and sulfuric acid droplets; (2) vapor pressure measurements of nitric acid and water over prototypical stratospheric aerosol (nitric acid trihydrate) surfaces; and (3) discharge flow tube kinetic studies of the HO2 radical using isotopic labeling for product channel and mechanistic analysis. Results from each of these areas demonstrate the versatility of TDL absorption spectroscopy for atmospheric chemistry applications.

  7. Passive sequestration of atmospheric CO2 through coupled plant-mineral reactions in urban soils.

    Science.gov (United States)

    Manning, David A C; Renforth, Phil

    2013-01-01

    Photosynthetic removal of CO(2) from the atmosphere is an important planetary carbon dioxide removal mechanism. Naturally, an amount equivalent to all atmospheric carbon passes through the coupled plant-soil system within 7 years. Plants cycle up to 40% of photosynthesized carbon through their roots, providing a flux of C at depth into the soil system. Root-exuded carboxylic acids have the potential to supply 4-5 micromoles C hr(-1)g(-1) fresh weight to the soil solution, and enhance silicate mineral weathering. Ultimately, the final product of these root-driven processes is CO(2), present in solution as bicarbonate. This combines with Ca liberated by corrosion associated with silicate mineral weathering to enter the soil-water system and to produce pedogenic calcium carbonate precipitates. Combining understanding of photosynthesis and plant root physiology with knowledge of mineral weathering provides an opportunity to design artificial soils or to plan land use in ways that maximize removal and sequestration of atmospheric CO(2) through artificially enhanced pedogenic carbonate precipitation. This process requires relatively low energy and infrastructure inputs. It offers a sustainable carbon dioxide removal mechanism analogous to the use of constructed wetlands for the passive remediation of contaminated waters, and is likely to achieve wide public acceptance. PMID:22616942

  8. Computational study of the reaction mechanism and kinetics of ethyl acrylate ozonolysis in atmosphere

    Science.gov (United States)

    Sun, Yanhui; Cao, Haijie; Han, Dandan; Li, Jing; He, Maoxia; Wang, Chen

    2012-06-01

    The reaction mechanism for the ozonolysis of ethyl acrylate (EA) has been investigated at the CCSD(T)/6-31G(d)+CF//B3LYP/6-31+G(d,p) level of theory. The profile of the potential energy surface (PES) is constructed. Ozone adds to EA via a cyclic transition state to produce a highly unstable primary ozonide which can decompose readily. Over the temperature range of 200-2000 K, the total and individual rate constants are obtained by employing multichannel Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The calculated rate constants are 1.37 × 10-18 cm3 molecule-1 s-1 at 294 K and 1.65 × 10-18 cm3 molecule-1 s-1 at 298 K under the pressure of 760 Torr. The main products of the reactions are ethyl glyoxylate and formaldehyde. These results are in good agreement with the previous experimental data. Several experimental uncertain products are identified. The branching ratios of main reaction paths are also discussed at different temperatures and pressures.

  9. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2008-11-01

    Full Text Available We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS, a proton transfer reaction mass spectrometer (PTR-MS, and a thermal desorption aerosol GC-MS (TAG – and found to be abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO, a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg−1h−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  10. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2009-03-01

    Full Text Available We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS, a proton transfer reaction mass spectrometer (PTR-MS, and a thermal desorption aerosol GC-MS (TAG – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO, a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg−1 h−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  11. Production of energetic light fragments in spallation reactions

    International Nuclear Information System (INIS)

    Different reaction mechanisms contribute to the production of light fragments (LF) from nuclear reactions. Available models cannot accurately predict emission of LF from arbitrary reactions. The cascade-exciton model (CEM) and the Los Alamos version of the quark-gluon string model (LAQGSM), as implemented in the CEM03.03 and LAQGSM03.03 event generators used in the Los Alamos Monte Carlo transport code MCNP6, describe quite well the spectra of fragments with sizes up to 4He across a broad range of target masses and incident energies. However, they do not predict high-energy tails for LF heavier than 4He. The standard versions of CEM and LAQGSM do not account for preequilibrium emission of LF larger than 4He. The aim of our work is to extend the preequilibrium model to include such processes. We do this by including the emission of fragments heavier than 4He at the preequilibrium stage, and using an improved version of the Fermi Break-up model, providing improved agreement with various experimental data

  12. Production of Energetic Light Fragments in Spallation Reactions

    Directory of Open Access Journals (Sweden)

    Mashnik Stepan G.

    2014-03-01

    Full Text Available Different reaction mechanisms contribute to the production of light fragments (LF from nuclear reactions. Available models cannot accurately predict emission of LF from arbitrary reactions. However, the emission of LF is important formany applications, such as cosmic-ray-induced single event upsets, radiation protection, and cancer therapy with proton and heavy-ion beams, to name just a few. The cascade-exciton model (CEM and the Los Alamos version of the quark-gluon string model (LAQGSM, as implemented in the CEM03.03 and LAQGSM03.03 event generators used in the Los Alamos Monte Carlo transport code MCNP6, describe quite well the spectra of fragments with sizes up to 4He across a broad range of target masses and incident energies. However, they do not predict high-energy tails for LF heavier than 4He. The standard versions of CEM and LAQGSM do not account for preequilibrium emission of LF larger than 4He. The aim of our work is to extend the preequilibrium model to include such processes. We do this by including the emission of fragments heavier than 4He at the preequilibrium stage, and using an improved version of the Fermi Break-up model, providing improved agreement with various experimental data.

  13. Energy dependences and product channels of ion-molecule-reactions

    International Nuclear Information System (INIS)

    For the investigation of ion-molecule-reactions a drift technique has been developed, making use of selected ion injection into a slow flow drift tube through an aspirator system similar to the one of Adams and Smith but operating under buffer flow rates as small as a few STP cm3 sec-1. Three groups of results have been obtained so far with this apparatus: 1) Proton and Deuteron transfer from Ar H+ and ArD+. The proton and deuteron transfer from ArH+ and ArD+ to H2 and D2 respectively proceeds fast, with rate coefficients close to the theoretical limits. No isotopic exchange is observed in these reactions. Besides these investigations performed in a helium buffer, equilibrium measurements in an argon buffer allows to obtain the equilibrium constant K for the reactions ArH+ + H2 H3+ + Ar in the range from O 2+(4πsub(u)) in the charge transfer of Ar+ with 02. At elevated kinetic energies KEsub(cm) >- 1 eV a considerable fraction of the charge transfer from Ar+ to 02 proceeds via the slightly endoergic channel into 02+(4πsub(u)). This was proved indirectly by reacting the so produced 02+ further with Ar to which 02+(4πsub(u)) does charge transfer with a fast rate2 while 02+(X) cannot. 3) The charge transfer from Ne+ to various neutrals and the respective branching ratios have been investigated from near thermal to a few eV, KEsub(cm). Especially the slow reactions (at room temperatures), such as Ne+ with CH4, CO2 and CO show strong dependences and also their product channels change dramatically with energy, indicating the opening of endoergic channels at higher KEsub(cm). (Author)

  14. Removal of triclosan via peroxidases-mediated reactions in water: Reaction kinetics, products and detoxification.

    Science.gov (United States)

    Li, Jianhua; Peng, Jianbiao; Zhang, Ya; Ji, Yuefei; Shi, Huanhuan; Mao, Liang; Gao, Shixiang

    2016-06-01

    This study investigated and compared reaction kinetics, product characterization, and toxicity variation of triclosan (TCS) removal mediated by soybean peroxidase (SBP), a recognized potential peroxidase for removing phenolic pollutants, and the commonly used horseradish peroxidase (HRP) with the goal of assessing the technical feasibility of SBP-catalyzed removal of TCS. Reaction conditions such as pH, H2O2 concentration and enzyme dosage were found to have a strong influence on the removal efficiency of TCS. SBP can retain its catalytic ability to remove TCS over broad ranges of pH and H2O2 concentration, while the optimal pH and H2O2 concentration were 7.0 and 8μM, respectively. 98% TCS was removed with only 0.1UmL(-1) SBP in 30min reaction time, while an HRP dose of 0.3UmL(-1) was required to achieve the similar conversion. The catalytic performance of SBP towards TCS was more efficient than that of HRP, which can be explained by catalytic rate constant (KCAT) and catalytic efficiency (KCAT/KM) for the two enzymes. MS analysis in combination with quantum chemistry computation showed that the polymerization products were generated via CC and CO coupling pathways. The polymers were proved to be nontoxic through growth inhibition of green alga (Scenedesmus obliquus). Taking into consideration of the enzymatic treatment cost, SBP may be a better alternative to HRP upon the removal and detoxification of TCS in water/wastewater treatment. PMID:26921508

  15. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl amino substituted triazine amino... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  16. Study on influence of native oxide and corrosion products on atmospheric corrosion of pure Al

    International Nuclear Information System (INIS)

    Highlights: •Corrosion products layer is only formed in coastal atmosphere. •In coastal atmosphere, rate controlling step is diffusion process. •In rural atmosphere, rate controlling step is charge transfer process. •Pitting area increases greatly in coastal site, but slightly in rural site. -- Abstract: Effects of native oxide and corrosion products on atmospheric corrosion of aluminium in rural and coastal sites were studied by electrochemical impedance spectroscopy (EIS), open-circuit potential (OCP) and scanning electron microscope (SEM) techniques after outdoor exposure. In the rural atmosphere, only the compact, adhesive native oxide layer exists, and the rate controlling step is diffusion process, while in the coastal atmosphere, another loose, inadhesive corrosion products layer exists, and a charge transfer process controls the corrosion process. The pitting area in the coastal atmosphere increases over time more obviously than that in the rural atmosphere

  17. Experimental measurements of low temperature rate coefficients for neutral-neutral reactions of interest for atmospheric chemistry of Titan, Pluto and Triton: reactions of the CN radical.

    Science.gov (United States)

    Morales, Sébastien B; Le Picard, Sébastien D; Canosa, André; Sims, Ian R

    2010-01-01

    The kinetics of the reactions of cyano radical, CN (X2sigma+) with three hydrocarbons, propane (CH3CH2CH3), propene (CH3CH=CH2) and 1-butyne (CH[triple band]CCH2CH3) have been studied over the temperature range of 23-298 K using a CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in Uniform Supersonic Flow) apparatus combined with the pulsed laser photolysis-laser induced fluorescence technique. These reactions are of interest for the cold atmospheres of Titan, Pluto and Triton, as they might participate in the formation of nitrogen and carbon bearing molecules, including nitriles, that are thought to play an important role in the formation of hazes and biological molecules. All three reactions are rapid with rate coefficients in excess of 10(-10) cm3 molecule(-1) s(-1) at the lowest temperatures of this study and show behaviour characteristic of barrierless reactions. Temperature dependences, different for each reaction, are compared to those used in the most recent photochemical models of Titan's atmosphere. PMID:21302546

  18. Reaction products in mass spectrometry elucidated with infrared spectroscopy.

    Science.gov (United States)

    Polfer, Nick C; Oomens, Jos

    2007-08-01

    Determining the structure and dynamics of large biologically relevant molecules is one of the key challenges facing biology. Although X-ray crystallography (XRD) and nuclear magnetic resonance (NMR) yield accurate structural information, they are of limited use when sample quantities are low. Mass spectrometry (MS) on the other hand has been very successful in analyzing biological molecules down to atto-mole quantities and has hence begun to challenge XRD and NMR as the key technology in the life sciences. This trend has been further assisted by the development of MS techniques that yield structural information on biomolecules. Of these techniques, collision-induced dissociation (CID) and hydrogen/deuterium exchange (HDX) are among the most popular. Despite advances in applying these techniques, little direct experimental evidence had been available until recently to verify their proposed underlying reaction mechanisms. The possibility to record infrared spectra of mass-selected molecular ions has opened up a novel avenue in the structural characterization of ions and their reaction products. On account of its high pulse energies and wide wavelength tunability, the free electron laser for infrared experiments (FELIX) at FOM Rijnhuizen has been shown to be ideally suited to study trapped molecular ions with infrared photo-dissociation spectroscopy. In this paper, we review recent experiments in our laboratory on the infrared spectroscopic characterization of reaction products from CID and HDX, thereby corroborating some of the reaction mechanisms that have been proposed. In particular, it is shown that CID gives rise to linear fragment ion structures which have been proposed for some time, but also yields fully cyclical ring structures. These latter structures present a possible challenge for using tandem MS in the sequencing of peptides/proteins, as they can lead to a scrambling of the amino acid sequence information. In gas-phase HDX of an amino acid it is shown

  19. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with 1... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with...

  20. 40 CFR 721.10154 - Quaternary ammonium compounds, dicoco alkyldimethyl, chlorides, reaction products with silica.

    Science.gov (United States)

    2010-07-01

    ... alkyldimethyl, chlorides, reaction products with silica. 721.10154 Section 721.10154 Protection of Environment..., dicoco alkyldimethyl, chlorides, reaction products with silica. (a) Chemical substance and significant..., dicoco alkyldimethyl, chlorides, reaction products with silica (PMN P-08-157; CAS No. 956147-76-5)...

  1. [Preservation of bread and pastry products in a controlled atmosphere].

    Science.gov (United States)

    Manchon, P

    1978-01-01

    Industrial soft pastries and the various breads are cereals products containing a humidity which is favorable to the development of mouldiness. Different or various methods of conservation has been attempted. One interesting approach to the problem is packaging in controlled atmosphere. It requires adequate machinery and suitable conditioning materials. Jardry-Buquet and Hayssen's machines are rapidly described as well as some of the packing film used for making air-tight bags. Bad results were observed with nitrogen, argon and a mixture of nitrogen-carbon dioxide. The satisfactory results obtained with the nitrous oxide for cakes (especially fruit-cakes) and for the bread with a mixture of ethylene oxide-carbon dioxide are: a good conservation for a period of 4 to 6 months in both cases. Organoleptic qualities of the products are not significantly diminished after eight weeks of preservation. The gases contained on the bags are analysed at different periods and the progressive disappearance of the nitrous oxide as well as the athylene dioxide was measured. The compounds derivated from these gases were researched on different extracts. No derivatives of the nitrous oxide were observed. From the ethylene oxide, the derivatives found in the bread are diethylene glycol and 2-chloroethanol; their concentrations are respectively 100 and 300 ppm in the case of 85 : 15 mixture, but decrease to a mere trace and 45 ppm in the case of 98 : 2 mixture. The measure of humidity, of peroxides and of the staleness of crumb are favourable for a good conservation. PMID:707931

  2. INFLUENCE OF REACTION TEMPERATURE AND REACTION TIME ON PRODUCT FROM HYDROTHERMAL TREATMENT OF BIOMASS RESIDUE

    Directory of Open Access Journals (Sweden)

    Jakaphong Kongpanya

    2014-01-01

    Full Text Available Thailand is facing with problems associated with biomass residue such as palm oil residues (oil palm trunks, oil palm fronds, empty fruit bunches, shells and fibers. Biomass is promising source for the production of an array of energy-related produts including, liquid, solid and gaseous fuels, heat, chemicals electricity and other materials. Therefore, the use of biomass for energy is not still fully utilization due to the high moisture content, lower heating value of the energy unit or low bulk density and the problems withtar. While Thailand has high potential because the reisa lot of biomass that has not been utilizedfor example biomass residues from palm oil industry. About 2 million tons of empty fruit bunches in Thailand have great potential. This amount will continue increase with the rapid growth in the Thailand, the largest crude palm oil producer in the world. This amount will continue increase with the rapid growth in the Thailand palm oil industry. Therefore, a better method to manage such biomass residues is highly desired. One of the potential ways for alternative utilization of biomass is thermo-chemical process. Hydrothermal treatment is a process for making a homogenizinged, carbon rich and energy-dense solid fuel, called hydrochar. The objective of the study was to identify the effect of reaction temperature and reaction time for hydrothermal treatment of Empty Fruit Bunches (EFB. Influence of temperature 100°C, 150°C and 200°C for 30 to 90 min and active biogas process on 1.00-15.538 bars, within 1,000 mL stainless steel 316 batch-type reactor with a stirrer and there is an automatic temperature controller. Results showed that the highest chemical and physical properties of hydrochar product was achieved when operated on 200°C for 90 min. Maximum heating value was found that 5678 cal/g for EFB9. The result showed that the chemical and physical properties increased progressively with higher temperature. The results was

  3. OH-initiated oxidation of DMS/DMSO: reaction products at high NOx levels

    International Nuclear Information System (INIS)

    Dimethylsulphide (DMS) gas phase oxidation with OH radicals was investigated by long path FT-IR spectroscopy and by ion chromatography (IC) and HPLC-MS2 to quantify the reaction products and evaluate heterogeneous processes. The experiments were performed considering two different NOx (NO2+NO) levels. The initial concentration of NO2 was varied from 24 ppbV (NOx=1 ppmV) to 953 ppbV (NOx=10 ppmV). Photolysis of H2O2 was used as the OH-radical source. SO2, dimethylsulphoxide (DMSO), dimethylsulphone (DMSO2), methanesulphonic acid (MSA), methanesulphinic acid (MSIA) and methane sulphonyl peroxynitrate (MSPN) were identified as the main sulphur-containing products. The results indicate that higher NOx levels play a significant role in the chemistry of CH3S(O)x radical, influencing both the SO2/MSPN ratio and the amount of the sulphur species in the condensed phase, and that the NO2/NO ratio could influence the trends in the molar yields of the different products. For this reason the NOx content results a limiting parameter when on measure DMS in atmospheric environment. - High NOx levels play a significant role in the atmospheric chemistry DMS/DMSO

  4. Evaluation of Neutron Induced Reactions for 32 Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeong Il

    2007-02-15

    Neutron cross sections for 32 fission products were evaluated in the neutron-incident energy range from 10{sup -5} eV to 20 MeV. The list of fission products consists of the priority materials for several applications, extended to cover complete isotopic chains for three elements. The full list includes 8 individual isotopes, {sup 95}Mo, {sup 101}Ru, {sup 103}Rh, {sup 105}Pd, {sup 109}Ag, {sup 131}Xe, {sup 133}Cs, {sup 141}Pr, and 24 isotopes in complete isotopic chains for Nd (8), Sm (9) and Dy (7). Our evaluation methodology covers both the low energy region and the fast neutron region.In the low energy region, our evaluations are based on the latest data published in the Atlas of Neutron Resonances. This resource was used to infer both the thermal values and the resolved resonance parameters that were validated against the capture resonance integrals. In the unresolved resonance region we performed the additional evaluation by using the averages of the resolved resonances and adjusting them to the experimental data.In the fast neutron region our evaluations are based on the nuclear reaction model code EMPIRE-2.19 validated against the experimental data. EMPIRE is the modular system of codes consisting of many nuclear reaction models, including the spherical and deformed Optical Model, Hauser-Feshbach theory with the width fluctuation correction and complete gamma-ray emission cascade, DWBA, Multi-step Direct and Multi-step Compound models, and several versions of the phenomenological preequilibrium models. The code is equipped with a power full GUI, allowing an easy access to support libraries such as RIPL and CSISRS, the graphical package, as well the utility codes for formatting and checking. In general, in our calculations we used the Reference Input Parameter Library, RIPL, for the initial set model parameters. These parameters were properly adjusted to reproduce the available experimental data taken from the CSISRS library. Our evaluations cover cross

  5. Evaluation of Neutron Induced Reactions for 32 Fission Products

    International Nuclear Information System (INIS)

    Neutron cross sections for 32 fission products were evaluated in the neutron-incident energy range from 10-5 eV to 20 MeV. The list of fission products consists of the priority materials for several applications, extended to cover complete isotopic chains for three elements. The full list includes 8 individual isotopes, 95Mo, 101Ru, 103Rh, 105Pd, 109Ag, 131Xe, 133Cs, 141Pr, and 24 isotopes in complete isotopic chains for Nd (8), Sm (9) and Dy (7). Our evaluation methodology covers both the low energy region and the fast neutron region.In the low energy region, our evaluations are based on the latest data published in the Atlas of Neutron Resonances. This resource was used to infer both the thermal values and the resolved resonance parameters that were validated against the capture resonance integrals. In the unresolved resonance region we performed the additional evaluation by using the averages of the resolved resonances and adjusting them to the experimental data.In the fast neutron region our evaluations are based on the nuclear reaction model code EMPIRE-2.19 validated against the experimental data. EMPIRE is the modular system of codes consisting of many nuclear reaction models, including the spherical and deformed Optical Model, Hauser-Feshbach theory with the width fluctuation correction and complete gamma-ray emission cascade, DWBA, Multi-step Direct and Multi-step Compound models, and several versions of the phenomenological preequilibrium models. The code is equipped with a power full GUI, allowing an easy access to support libraries such as RIPL and CSISRS, the graphical package, as well the utility codes for formatting and checking. In general, in our calculations we used the Reference Input Parameter Library, RIPL, for the initial set model parameters. These parameters were properly adjusted to reproduce the available experimental data taken from the CSISRS library. Our evaluations cover cross sections for almost all reaction channels including photon

  6. Atmospheric CO2 uptake throughout bio-enhanced brucite-water reaction at Montecastelli serpentinites (Italy)

    Science.gov (United States)

    Bedini, Federica; Boschi, Chiara; Ménez, Benedicte; Perchiazzi, Natale; Zanchetta, Giovanni

    2014-05-01

    In the last several years, interactions between microorganisms and minerals have intrigued and catched the interest of the scientific community. Montecastelli serpentinites (Tuscany, Italy) are characterized by CO2-mineral carbonation, an important process which leads to spontaneous formation of carbonate phases uptaking atmospheric CO2. In the studied areas carbonate precipitates, mainly hydrated Mg-carbonates, are present in form of crusts, coating and spherules on exposed rock surfaces, and filling rock fractures. Petrographic and mineralogical observations revealed that Tuscan brucite-rich serpentinites hosts preserve their original chemical compositions with typical mesh-textured serpentine (± brucite) after olivine, magnetite-rich mesh rims and relicts of primary spinel. Representative hydrated carbonate samples have been collected in three different areas and analyzed to investigate the role of biological activity and its influence in the serpentine-hydrated Mg-carbonates reaction. The different types of whitish precipitates have been selected under binocular microscope for XRD analyses performed at the Dipartimento di Scienze della Terra (University of Pisa, Italy): their mineralogical composition consists of mainly hydromagnesite and variable amount of other metastable carbonate phases (i.e. nesquehonite, manasseite, pyroaurite, brugnatellite and aragonite). Moreover, the crystallinity analysis of whitish crust and spherules have been carried out by detailed and quantitative XRD analyses to testify a possible biologically controlled growth, inasmuch as the crystal structure of biominerals could be affected by many lattice defects (i.e. dislocations, twinning, etc.) and this observation cause low crystallinity of the mineral. The presence of microbial cells and relicts of organic matter has already been detected by confocal laser scanning microscopy (CLSM) combined with Raman spectromicroscopy in a previous study (Bedini et al., 2013). The presence of

  7. Maillard reaction products as antimicrobial components for packaging films.

    Science.gov (United States)

    Hauser, Carolin; Müller, Ulla; Sauer, Tanja; Augner, Kerstin; Pischetsrieder, Monika

    2014-02-15

    Active packaging foils with incorporated antimicrobial agents release the active ingredient during food storage. Maillard reaction products (MRPs) show antimicrobial activity that is at least partially mediated by H2O2. De novo generation of H2O2 by an MRP fraction, extracted from a ribose/lysine Maillard reaction mixture by 85% ethanol, was monitored at three concentrations (1.6, 16.1, and 32.3g/L) and three temperatures (4, 25, and 37 °C) between 0 and 96 h, reaching a maximum of 335 μM H2O2 (32.3g/L, 37 °C, 96 h). The active MRP fraction (16.1g/L) completely inhibited the growth of Escherichia coli for 24h and was therefore incorporated in a polyvinyl acetate-based lacquer and dispersed onto a low-density polyethylene film. The coated film generated about 100 μM H2O2 and resulted in a log-reduction of >5 log-cycles against E. coli. Thus, MRPs can be considered as active ingredients for antimicrobial packaging materials. PMID:24128521

  8. In vivo effects of Maillard reaction products derived from biscuits.

    Science.gov (United States)

    Patrignani, Mariela; Rinaldi, Gustavo Juan; Lupano, Cecilia Elena

    2016-04-01

    The antioxidant activity, antihypertensive effect and prebiotic activity of Maillard reaction products (MRPs) derived from biscuits were investigated in Wistar rats. Animals were fed the following diets for 6 weeks: control (AIN-93 diet); Asc-diet (AIN-93 diet with ascorbic acid in the drinking water); HT-B diet (containing high amount of MRP derived from biscuits) and LT-B diet (containing negligible amounts of biscuit MRP). Serum antioxidant activity (FRAP, ABTS), as well as lipid peroxidation (TBARS) were determined at the end of the experiment. Results showed that dietary MRP reduced the food efficiency, increased the antioxidant activity of serum, increased the ratio between lactic and total aerobic bacteria, increased water-holding capacity of faeces and reduced blood pressure, but did not reduce mineral absorption. Therefore, the biscuit MRP functional claims could be demonstrated by an in vivo study. PMID:26593484

  9. Sorption enhanced reaction process (SERP) for the production of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Hufton, J.; Mayorga, S.; Gaffney, T.; Nataraj, S.; Rao, M.; Sircar, S. [Air Products and Chemicals, Inc., Allentown, PA (United States)

    1998-08-01

    The novel Sorption Enhanced Reaction Process has the potential to decrease the cost of hydrogen production by steam methane reforming. Current effort for development of this technology has focused on adsorbent development, experimental process concept testing, and process development and design. A preferred CO{sub 2} adsorbent, K{sub 2}CO{sub 3} promoted hydrotalcite, satisfies all of the performance targets and it has been scaled up for process testing. A separate class of adsorbents has been identified which could potentially improve the performance of the H{sub 2}-SER process. Although this material exhibits improved CO{sub 2} adsorption capacity compared to the HTC adsorbent, its hydrothermal stability must be improved. Single-step process experiments (not cyclic) indicate that the H{sub 2}-SER reactor performance during the reaction step improves with decreasing pressure and increasing temperature and steam to methane ratio in the feed. Methane conversion in the H{sub 2}-SER reactor is higher than for a conventional catalyst-only reactor operated at similar temperature and pressure. The reactor effluent gas consists of 90+% H{sub 2}, balance CH{sub 4}, with only trace levels (< 50 ppm) of carbon oxides. A best-case process design (2.5 MMSCFD of 99.9+% H{sub 2}) based on the HTC adsorbent properties and a revised SER process cycle has been generated. Economic analysis of this design indicates the process has the potential to reduce the H{sub 2} product cost by 25--31% compared to conventional steam methane reforming.

  10. Effect of reaction atmosphere on particle morphology of TiO{sub 2} produced by thermal decomposition of titanium tetraisopropoxide

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae Gil; Park, Kyun Young [Kongju National University, Department of Chemical Engineering (Korea, Republic of)], E-mail: kypark@kongju.ac.kr

    2006-04-15

    Thermal decomposition of titanium tetraisopropoxide (TTIP) was carried out in varying reaction atmospheres: nitrogen, oxygen, and nitrogen plus water vapor. The effect of reaction atmosphere on the morphology, size, and crystalline structure of produced TiO{sub 2} particles was studied. The reactor used was similar to the microreactor proposed earlier by Park et al. (2001, J. Nanopart. Res., 3, 309-319), but for a modification in the precursor evaporator. The reactor temperature was varied from 300 to 700 deg. C and the TTIP concentration in the evaporator from 1.0 to 7.0 mol%, holding the reactor residence time at 0.7 s. The primary-particle size was in the range 25-250 nm, varying with operating condition. The crystalline structure was amorphous in nitrogen, a mixture of rutile and anatase in nitrogen plus water vapor, and anatase in oxygen atmospheres. In nitrogen, agglomerates composed of very small particles whose individual boundaries are not clearly distinguished were produced. In oxygen, the particles composing an agglomerate became larger and were clearly spherical. As the atmosphere was varied to the nitrogen plus water vapor, the particle size increased further. The variation of primary particle size with reaction atmosphere was discussed in comparison with previous experimental data.

  11. Atmospheric Chemistry of CF3CF=CH2: Reactions With Cl Atoms, OH Radicals and Ozone

    Science.gov (United States)

    Sulbaek Andersen, M. P.; Javadi, M. S.; Nielsen, O. J.; Hurley, M. D.; Wallington, T. J.; Singh, R.

    2006-12-01

    The detrimental effects of chlorine chemistry on stratospheric ozone levels are well established. Consequently, there has been a concerted international effort to find replacements for chlorofluorocarbons (CFCs) used previously as electronic equipment cleaners, heat transfer agents, refrigerants, and carrier fluids for lubricant deposition. The replacements for CFCs, hydrofluorocarbons (HFCs) and hydrofluorochlorocarbons (HCFCs), have found widespread industrial use over the past decade. Unsaturated fluorinated hydrocarbons are a new class of compounds which have been developed to replace CFCs and HFCs in air condition units. Prior to any large-scale industrial use an assessment of the atmospheric chemistry, and hence environmental impact, of these compounds is needed. To address this need the atmospheric chemistry of CF3CF=CH2 was investigated. Smog chamber/FTIR techniques were used to determine the following properties for this compound: (i) kinetics of reactions with chlorine atoms (ii) kinetics of reactions with hydroxyl radicals (iii) kinetics of reactions with ozone, (iv) atmospheric lifetimes, (v) atmospheric degradation mechanism, and (vi) global warming potentials. The results are discussed with regard to the environmental impact of CF3CF=CH2 and the atmospheric chemistry of unsaturated fluorinated hydrocarbons.

  12. Sintering uranium oxide in the reaction product of hydrogen-carbon dioxide mixtures

    International Nuclear Information System (INIS)

    Compacted pellets of uranium oxide alone or containing one or more additives such as plutonium dioxide, gadolinium oxide, titanium dioxide, silica, and alumina are heated to 900 to 15990C in the presence of a mixture of hydrogen and carbon dioxide, either alone or with an inert carrier gas and held at the desired temperature in this atmosphere to sinter the pellets. The sintered pellets are then cooled in an atmosphere having an oxygen partial pressure of 10-4 to 10-18 atm of oxygen such as dry hydrogen, wet hydrogen, dry carbon monoxide, wet carbon monoxide, inert gases such as nitrogen, argon, helium, and neon and mixtures of ayny of the foregoing including a mixture of hydrogen and carbon dioxide. The ratio of hydrogen to carbon dioxide in the gas mixture fed to the furnace is controlled to give a ratio of oxygen to uranium atoms in the sintered particles within the range of 1.98:1 to about 2.10:1. The water vapor present in the reaction products in the furnace atmosphere acts as a hydrolysis agent to aid removal of fluoride should such impurity be present in the uranium oxide. (U.S.)

  13. Sorption Enhanced Reaction Process (SERP) for production of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Anand, M.; Hufton, J.; Mayorga, S. [Air Products and Chemicals, Inc., Allentown, PA (United States)] [and others

    1996-10-01

    Sorption Enhanced Reaction Process (SERP) is a novel process that is being developed for the production of lower cost hydrogen by steam-methane reforming (SMR). In this process the reaction of methane with steam is carried out in the presence of an admixture of a catalyst and a selective adsorbent for carbon dioxide. The key consequences of SERP are: (i) reformation reaction is carried out at a significantly lower temperature (300-500{degrees}C) than that in a conventional SMR reactor (800-1100{degrees}C), while achieving the same conversion of methane to hydrogen, (ii) the product hydrogen is obtained at reactor pressure (200-400 psig) and at 98+% purity directly from the reactor (compared to only 70-75% H{sub 2} from conventional SMR reactor), (iii) downstream hydrogen purification step is either eliminated or significantly reduced in size. The first phase of the program has focused on the development of a sorbent for CO{sub 2} which has (a) reversible CO{sub 2} capacity >0.3 mmol/g at low partial pressures of CO{sub 2} (0.1 - 1.0 atm) in the presence of excess steam (pH{sub 2}O/pCO{sub 2}>20) at 400-500{degrees}C and (b) fast sorption-desorption kinetics for CO{sub 2}, at 400-500{degrees}C. Several families of supported sorbents have been identified that meet the target CO{sub 2} capacity. A few of these sorbents have been tested under repeated sorption/desorption cycles and extended exposure to high pressure steam at 400-500{degrees}C. One sorbent has been scaled up to larger quantities (2-3 kg) and tested in the laboratory process equipment for sorption and desorption kinetics of CO{sub 2}. The CO{sub 2}, sorption and desorption kinetics are desirably fast. This was a critical path item for the first phase of the program and now has been successfully demonstrated. A reactor has been designed that will allow nearly isothermal operation for SERP-SMR. This reactor was integrated into an overall process flow diagram for the SERP-SMR process.

  14. Mechanism and kinetics of the reaction of 1,4-thioxane with O3 in the atmosphere - A theoretical study

    Science.gov (United States)

    Sandhiya, L.; Kolandaivel, P.; Senthilkumar, K.

    2012-02-01

    A theoretical investigation of the atmospheric oxidation of a cyclic organosulfur compound 1,4-thioxane by O3 is performed. The pathways for the reaction of 1,4-thioxane with O3 have been modeled using B3LYP, M06-2X, MPW1K and MP2 level of theories with 6-31G(d,p), 6-311G(d,p) and 6-31+G(d,p) basis sets. The reaction is initiated by the formation of a primary ozonide, followed by a biradical, which on subsequent reactions with other atmospheric species produces hydroxyl radical, hydrogen peroxides and organic peroxides. The results obtained from DFT calculations were subsequently used to perform canonical variational transition-state theory calculations to determine the rate constant. The calculated rate constant is in good agreement with the available experimental data.

  15. Solar Thermochemical Hydrogen Production via Terbium Oxide Based Redox Reactions

    Directory of Open Access Journals (Sweden)

    Rahul Bhosale

    2016-01-01

    Full Text Available The computational thermodynamic modeling of the terbium oxide based two-step solar thermochemical water splitting (Tb-WS cycle is reported. The 1st step of the Tb-WS cycle involves thermal reduction of TbO2 into Tb and O2, whereas the 2nd step corresponds to the production of H2 through Tb oxidation by water splitting reaction. Equilibrium compositions associated with the thermal reduction and water splitting steps were determined via HSC simulations. Influence of oxygen partial pressure in the inert gas on thermal reduction of TbO2 and effect of water splitting temperature (TL on Gibbs free energy related to the H2 production step were examined in detail. The cycle (ηcycle and solar-to-fuel energy conversion (ηsolar-to-fuel efficiency of the Tb-WS cycle were determined by performing the second-law thermodynamic analysis. Results obtained indicate that ηcycle and ηsolar-to-fuel increase with the decrease in oxygen partial pressure in the inert flushing gas and thermal reduction temperature (TH. It was also realized that the recuperation of the heat released by the water splitting reactor and quench unit further enhances the solar reactor efficiency. At TH=2280 K, by applying 60% heat recuperation, maximum ηcycle of 39.0% and ηsolar-to-fuel of 47.1% for the Tb-WS cycle can be attained.

  16. Measurement of Charmed Particle Production in Hadronic Reactions

    CERN Multimedia

    2002-01-01

    The aim of the experiment is to measure the production cross-section for charmed particles in hadronic reactions, study their production mechanism, and search for excited charmed hadrons.\\\\ \\\\ Charmed Mesons and Baryons will be measured in @p and p interactions on Beryllium between 100 and 200 GeV/c. The trigger will be on an electron from the leptonic decay of one charmed particle by signals from the Cerenkov counter (Ce), the electron trigger calorimeter (eCal), scintillation counters, and proportional wire chambers. The accompanying charmed particle will be measured via its hadronic decay in a two-stage magnetic spectrometer with drift chambers (arms 2, 3a, 3b, 3c), two large-area multicell Cerenkov counters (C2, C3) and a large-area shower counter (@g-CAL). The particles which can be measured and identified include @g, e, @p@+, @p|0, K@+, p, @* so that a large number of hadronic decay modes of charmed particles can be studied. \\\\ \\\\ A silicon counter telescope with 5 @mm spatial resolution will measure se...

  17. Chemical Reaction and Flow Modeling in Fullerene and Nanotube Production

    Science.gov (United States)

    Scott, Carl D.; Farhat, Samir; Greendyke, Robert B.

    2004-01-01

    The development of processes to produce fullerenes and carbon nanotubes has largely been empirical. Fullerenes were first discovered in the soot produced by laser ablation of graphite [1]and then in the soot of electric arc evaporated carbon. Techniques and conditions for producing larger and larger quantities of fullerenes depended mainly on trial and error empirical variations of these processes, with attempts to scale them up by using larger electrodes and targets and higher power. Various concepts of how fullerenes and carbon nanotubes were formed were put forth, but very little was done based on chemical kinetics of the reactions. This was mainly due to the complex mixture of species and complex nature of conditions in the reactors. Temperatures in the reactors varied from several thousand degrees Kelvin down to near room temperature. There are hundreds of species possible, ranging from atomic carbon to large clusters of carbonaceous soot, and metallic catalyst atoms to metal clusters, to complexes of metals and carbon. Most of the chemical kinetics of the reactions and the thermodynamic properties of clusters and complexes have only been approximated. In addition, flow conditions in the reactors are transient or unsteady, and three dimensional, with steep spatial gradients of temperature and species concentrations. All these factors make computational simulations of reactors very complex and challenging. This article addresses the development of the chemical reaction involved in fullerene production and extends this to production of carbon nanotubes by the laser ablation/oven process and by the electric arc evaporation process. In addition, the high-pressure carbon monoxide (HiPco) process is discussed. The article is in several parts. The first one addresses the thermochemical aspects of modeling; and considers the development of chemical rate equations, estimates of reaction rates, and thermodynamic properties where they are available. The second part

  18. Kinetics of the unimolecular reaction of CH2OO and the bimolecular reactions with the water monomer, acetaldehyde and acetone under atmospheric conditions.

    Science.gov (United States)

    Berndt, Torsten; Kaethner, Ralf; Voigtländer, Jens; Stratmann, Frank; Pfeifle, Mark; Reichle, Patrick; Sipilä, Mikko; Kulmala, Markku; Olzmann, Matthias

    2015-08-14

    Stabilized Criegee Intermediates (sCIs) have been identified as oxidants of atmospheric trace gases such as SO2, NO2, carboxylic acids or carbonyls. The atmospheric sCI concentrations, and accordingly their importance for trace gas oxidation, are controlled by the rate of the most important loss processes, very likely the unimolecular reactions and the reaction with water vapour (monomer and dimer) ubiquitously present at high concentrations in the troposphere. In this study, the rate coefficients of the unimolecular reaction of the simplest sCI, formaldehyde oxide, CH2OO, and its bimolecular reaction with the water monomer have been experimentally determined at T = (297 ± 1) K and at atmospheric pressure by using a free-jet flow system. CH2OO was produced by the reaction of ozone with C2H4, and CH2OO concentrations were probed indirectly by detecting H2SO4 after titration with SO2. Time-resolved experiments yield a rate coefficient of the unimolecular reaction of k(uni) = (0.19 ± 0.07) s(-1), a value that is supported by quantum-chemical and statistical rate theory calculations as well as by additional measurements performed under CH2OO steady-state conditions. A rate coefficient of k(CH2OO+H2O) = (3.2 ± 1.2) × 10(-16) cm(3) molecule(-1) s(-1) has been determined for sufficiently low H2O concentrations (<10(15) molecule cm(-3)) that allow separation from the CH2OO reaction with the water dimer. In order to evaluate the accuracy of the experimental approach, the rate coefficients of the reactions with acetaldehyde and acetone were reinvestigated. The obtained rate coefficients k(CH2OO+acetald) = (1.7 ± 0.5) × 10(-12) and k(CH2OO+acetone) = (3.4 ± 0.9) × 10(-13) cm(3) molecule(-1) s(-1) are in good agreement with literature data. PMID:26159709

  19. Inhibitory Effect of Maillard Reaction Products on Growth of the Aerobic Marine Hyperthermophilic Archaeon Aeropyrum pernix

    OpenAIRE

    Kim, Kee Woung; Lee, Sun Bok

    2003-01-01

    It was found that the growth of Aeropyrum pernix was severely inhibited in a medium containing reducing sugars and tryptone due to the formation of Maillard reaction products. The rate of the Maillard browning reaction was markedly enhanced under aerobic conditions, and the addition of Maillard reaction products to the culture medium caused fatal growth inhibition.

  20. Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes

    Science.gov (United States)

    Lifton, Nathaniel; Sato, Tatsuhiko; Dunai, Tibor J.

    2014-01-01

    Several models have been proposed for scaling in situ cosmogenic nuclide production rates from the relatively few sites where they have been measured to other sites of interest. Two main types of models are recognized: (1) those based on data from nuclear disintegrations in photographic emulsions combined with various neutron detectors, and (2) those based largely on neutron monitor data. However, stubborn discrepancies between these model types have led to frequent confusion when calculating surface exposure ages from production rates derived from the models. To help resolve these discrepancies and identify the sources of potential biases in each model, we have developed a new scaling model based on analytical approximations to modeled fluxes of the main atmospheric cosmic-ray particles responsible for in situ cosmogenic nuclide production. Both the analytical formulations and the Monte Carlo model fluxes on which they are based agree well with measured atmospheric fluxes of neutrons, protons, and muons, indicating they can serve as a robust estimate of the atmospheric cosmic-ray flux based on first principles. We are also using updated records for quantifying temporal and spatial variability in geomagnetic and solar modulation effects on the fluxes. A key advantage of this new model (herein termed LSD) over previous Monte Carlo models of cosmogenic nuclide production is that it allows for faster estimation of scaling factors based on time-varying geomagnetic and solar inputs. Comparing scaling predictions derived from the LSD model with those of previously published models suggest potential sources of bias in the latter can be largely attributed to two factors: different energy responses of the secondary neutron detectors used in developing the models, and different geomagnetic parameterizations. Given that the LSD model generates flux spectra for each cosmic-ray particle of interest, it is also relatively straightforward to generate nuclide-specific scaling

  1. Measurement of atmospheric sesquiterpenes by proton transfer reaction-mass spectrometry (PTR-MS

    Directory of Open Access Journals (Sweden)

    S. Kim

    2008-12-01

    Full Text Available The ability to measure sesquiterpenes (SQT; C15H24 by a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS was investigated with SQT standards, prepared by a capillary diffusion method, and the estimated mixing ratios, derived from the counts of product ions and proton transfer reaction constants were intercompared with measured mixing ratios, measured by a complementary Gas Chromatograph (GC coupled to a Flame Ionization Detector (GC-FID. Product ion distributions due to soft-ionization occurring in a selected ion drift tube via proton transfer were measured as a function of collision energies. Results after the consideration of the mass discrimination of the PTR-MS system suggest that quantitative SQT measurements within 20% accuracy can be achieved with PTR-MS if two major product ions (m/z 149+ and 205+ out of seven major product ions (m/z 81+, 95+, 109+, 123+, 135+, 149+ and 205+ are accounted for. Bicyclic sesquiterpenes, i.e. β-caryophyllene and α-humulene, showed considerable fragmentation causing the accuracy of their analysis to be reduced to 50% if only the parent ion (m/z 205 is considered. These findings were applied to a field dataset collected above a deciduous forest at the PROPHET (Program for Research on Oxidants: Photochemistry, Emissions, and Transport research station in 2005. Inferred Average daytime ecosystem scale mixing ratios (fluxes of isoprene, sum of monoterpenes (MT, and sum of SQT exhibited values of 15 μg m−3 (4.5 mg m−2 h−1, 1.2 μg m−3 (0.21 mg m−2 h−1 and 0.0016 μg m−3 (0.10 mgm−2 h−1 respectively. A range of MT and SQT reactivities with respect to the OH radical was calculated and compared to an earlier study inferring significantly underestimated OH

  2. Production of gamma rays with energies greater than 30 MeV in the atmosphere

    Science.gov (United States)

    Thompson, D.; Fichtel, C.; Kniffen, D.

    1974-01-01

    A three-dimensional study of atmospheric gamma rays with energy greater than 30 MeV has been carried out. Experimental results were obtained from four balloon flights from Palestine, Texas, with a 15 cm by 15 cm digitized wire grid spark chamber. The energy spectrum for downward-moving gamma rays steepens with increasing atmospheric depth. Near the top of the atmosphere, the spectrum steepens with increasing zenith angle. Experimental results compare reasonably well with a three-dimensional Monte Carlo calculation of atmospheric gamma ray production. Inclusion of upward-moving gamma rays makes possible the use of atmospheric secondaries for in-flight calibration of satellite gamma ray detectors.

  3. KRATTA, a versatile triple telescope array for charged reaction products

    CERN Document Server

    Łukasik, J; Budzanowski, A; Czech, B; Skwirczyńska, I; Brzychczyk, J; Adamczyk, M; Kupny, S; Lasko, P; Sosin, Z; Wieloch, A; Kiš, M; Leifels, Y; Trautmann, W

    2013-01-01

    A new detection system KRATTA, Krak\\'ow Triple Telescope Array, is presented. This versatile, low threshold, broad energy range system has been built to measure the energy, emission angle, and isotopic composition of light charged reaction products. It consists of 38 independent modules which can be arranged in an arbitrary configuration. A single module, covering actively about 4.5 msr of the solid angle at the optimal distance of 40 cm from the target, consists of three identical, 0.500 mm thick, large area photodiodes, used also for direct detection, and of two CsI(1500 ppm Tl) crystals of 2.5 and 12.5 cm length, respectively. All the signals are digitally processed. The lower identification threshold, due to the thickness of the first photodiode, has been reduced to about 2.5 MeV for protons (~0.065 mm of Si equivalent) by applying a pulse shape analysis. The pulse shape analysis allowed also to decompose the complex signals from the middle photodiode into their ionization and scintillation components and...

  4. Reaction of carbon tetrachloride with methane in a non-equilibrium plasma at atmospheric pressure, and characterisation of the polymer thus formed

    International Nuclear Information System (INIS)

    Highlights: • CCl4 remediation using non-equilibrium plasma and non-oxidative conditions is proposed. • The reaction mechanism relies on experimental data and quantum chemical analysis. • Comprehensive mass balance for the reaction is provided. • CCl4 is converted to an environmentally benign and potentially useful polymer. • Characterisation of the polymer structure based on NMR and FTIR analyses is presented. - Abstract: In this paper we focus on the development of a methodology for treatment of carbon tetrachloride utilising a non-equilibrium plasma operating at atmospheric pressure, which is not singularly aimed at destroying carbon tetrachloride but rather at converting it to a non-hazardous, potentially valuable commodity. This method encompasses the reaction of carbon tetrachloride and methane, with argon as a carrier gas, in a quartz dielectric barrier discharge reactor. The reaction is performed under non-oxidative conditions. Possible pathways for formation of major products based on experimental results and supported by quantum chemical calculations are outlined in the paper. We elucidate important parameters such as carbon tetrachloride conversion, product distribution, mass balance and characterise the chlorinated polymer formed in the process

  5. Mechanism for formation of atmospheric Cl atom precursors in the reaction of dinitrogen oxides with HCl/Cl(-) on aqueous films.

    Science.gov (United States)

    Hammerich, Audrey Dell; Finlayson-Pitts, Barbara J; Gerber, R Benny

    2015-07-15

    Nitryl chloride (ClNO2) and nitrosyl chloride (ClNO) are potential sources of highly reactive atmospheric chlorine atoms, hence of much interest, but their formation pathways are unknown. This work predicts production of these nitrogen oxychlorides from ab initio molecular dynamics (AIMD) simulations of N2O5 or an NO2 dimer on the surface of a thin film of water which is struck by gaseous HCl. Both of these heterogeneous reactions proceed at the liquid/vapor interface by an SN2 mechanism where the nucleophile is chloride ion formed from the ionization of HCl on the aqueous surface. The film of water enhances the otherwise very slow gas phase reaction to occur by (1) stabilizing and localizing the adsorbed N2O5 or NO2 dimer so it is physically accessible for reaction, (2) ionizing the impinging HCl, and (3) activating the adsorbed oxide for nucleophilic attack by chloride. Though both nitrogen oxychloride products are produced by SN2 reactions, the N2O5 mechanism is unusual in that the electrophilic N atom to be attacked oscillates between the two normally equivalent NO2 groups. Chloride ion is found to react with N2O5 less efficiently than with N2O4. The simulations provide an explanation for this. These substitution/elimination mechanisms are new for NOx/y chemistry on thin water films and cannot be derived from small cluster models. PMID:26140681

  6. An assessment of potential degradation products in the gas-phase reactions of alternative fluorocarbons in the troposphere

    Science.gov (United States)

    Niki, Hiromi

    1990-01-01

    Tropospheric chemical transformations of alternative hydrofluorocarbons (HCF's) and hydrochlorofluorocarbons (HCFC's) are governed by hydroxyl radical initiated oxidation processes, which are likely to be analogous to those known for alkanes and chloroalkanes. A schematic diagram is used to illustrate plausible reaction mechanisms for their atmospheric degradation, where R, R', and R'' denote the F- and/or Cl-substituted alkyl groups derived from HCF's and HCFC's subsequent th the initial H atom abstraction by HO radicals. At present, virtually no kinetic data exist for the majority of these reactions, particularly for those involving RO. Potential degradation intermediates and final products include a large variety of fluorine- and/or chlorine-containing carbonyls, acids, peroxy acids, alcohols, hydrogen peroxides, nitrates and peroxy nitrates, as summarized in the attached table. Probably atmospheric lifetimes of these compounds were also estimated. For some carbonyl and nitrate products shown in this table, there seem to be no significant gas-phase removal mechanisms. Further chemical kinetics and photochemical data are needed to quantitatively assess the atmospheric fate of HCF's and HCFC's, and of the degradation products postulated in this report.

  7. Characterization of corrosion products formed on steels in the first months of atmospheric exposure

    OpenAIRE

    Antunes Renato Altobelli; Costa Isolda; Faria Dalva Lúcia Araújo de

    2003-01-01

    The corrosion products of carbon steel and weathering steel exposed to three different types of atmospheres, at times ranging from one to three months, have been identified. The steels were exposed in an industrial site, an urban site (São Paulo City, Brazil), and a humid site. The effect of the steel type on the corrosion products formed in the early stages of atmospheric corrosion has been evaluated. The corrosion products formed at the various exposure locations were characterized by Raman...

  8. Atmospheric chemistry of HFC-134a. Kinetic and mechanistic study of the CF3CFHO2 + NO2 reaction

    DEFF Research Database (Denmark)

    Møgelberg, T.E.; Nielsen, O.J.; Sehested, J.;

    1994-01-01

    A pulse radiolysis system was used to study the kinetics of the reaction of CF3CFHO2 with NO2. By monitoring the rate of the decay of NO2 using its absorption at 400 nm the reaction rate constant was determined to be k = (5.0 +/- 0.5) x 10(-12) cm3 molecule-1 s-1. A long path length Fourier......-transform infrared technique was used to investigate the thermal decomposition of the product CF3CFHO2NO2. At 296 K in the presence of 700 Torr of air, decomposition of CF3CFHO2NO2 was rapid (greater than 90% decomposition within 3 min). The results are discussed in the context of atmospheric chemistry of CF3CFH2...

  9. On-line measurements of α-pinene ozonolysis products using an atmospheric pressure chemical ionisation ion-trap mass spectrometer

    Science.gov (United States)

    Warscheid, Bettina; Hoffmann, Thorsten

    An on-line technique to investigate complex organic oxidation reactions in environmental chamber experiments is presented. The method is based on the direct introduction of the chamber air into an atmospheric pressure ion source of a commercial ion-trap mass spectrometer. To demonstrate the analytical potential of the method (atmospheric pressure chemical ionisation/mass spectrometry, APCI/MS), the ozonolysis of α-pinene was investigated in a series of experiments performed in various sized reaction chambers at atmospheric pressure and 296 K in synthetic air. Investigations were focussed on the influence of the water vapour concentration on the formation of the predominant oxidation product, pinonaldehyde, derived from the α-pinene/ozone reaction. Quantification of pinonaldehyde was achieved by conducting a standard addition technique. The molar yield of pinonaldehyde was found to depend strongly on the actual water vapour concentration between ozonide, indicating a branching ratio of 0.35/0.65.

  10. Sporicidal effects of iodine-oxide thermite reaction products

    Science.gov (United States)

    Russell, Rod; Bless, Stephan; Blinkova, Alexandra; Chen, Tiffany

    2012-03-01

    Iodine pentoxide-aluminum thermite reactions have been driven by impacts at 1000 m/s on steel plates 3 mm or thicker. This reaction releases iodine gas that is known to be a sporicide. To test the impact reactions for sporicidal effects, reactions took place in closed chambers containing dried Bacillus subtilis spores. The reduction in colony-forming units was dependent on the exposure time; long exposure times resulted in a 105 decrease in germination rate. This was shown to be due to the gas exposure rather than the heat or turbulence. Sporicidal effectiveness was increased by adding neodymium and saran resin.

  11. Mathematical Modeling of Complex Reaction Systems for Computer-Aided Control and its Illustration on Atmospheric Chemistry

    Science.gov (United States)

    Amiryan, A.

    2015-12-01

    Modeling of sequential process has its own importance in Atmospheric Chemistry. Numerical calculations which allow to predict separate stages and components of chemical reaction make possible the reaction management, such is the new and perspective direction in chemical researches. Chemical processes basically pass multiple simple stages where various atoms and radicals participate. The complex chain of chemical reactionary systems complicates their research and the research is impossible without new methods of mathematical simulation and high technologies which allow not only to explain results of experiments but also to predict dynamics of processes. A new program package is suggested for solving research problems of chemical kinetics. The program is tested on different illustrative examples on Atmospheric Chemistry and installed in various scientific and educational institutions.

  12. A COMBINED REACTION/PRODUCT RECOVERY PROCESS FOR THE CONTINUOUS PRODUCTION OF BIODIESEL

    Energy Technology Data Exchange (ETDEWEB)

    Birdwell, J.F., Jr.; McFarlane, J.; Schuh, D.L.; Tsouris, C; Day, J.N. (Nu-Energie, LLC); Hullette, J.N. (Nu-Energie, LLC)

    2009-09-01

    Oak Ridge National Laboratory (ORNL) and Nu-Energie, LLC entered into a Cooperative Research And Development Agreement (CRADA) for the purpose of demonstrating and deploying a novel technology for the continuous synthesis and recovery of biodiesel from the transesterification of triglycerides. The focus of the work was the demonstration of a combination Couette reactor and centrifugal separator - an invention of ORNL researchers - that facilitates both product synthesis and recovery from reaction byproducts in the same apparatus. At present, transesterification of triglycerides to produce biodiesel is performed in batch-type reactors with an excess of a chemical catalyst, which is required to achieve high reactant conversions in reasonable reaction times (e.g., 1 hour). The need for long reactor residence times requires use of large reactors and ancillary equipment (e.g., feed and product tankage), and correspondingly large facilities, in order to obtain the economy of scale required to make the process economically viable. Hence, the goal of this CRADA was to demonstrate successful, extended operation of a laboratory-scale reactor/separator prototype to process typical industrial reactant materials, and to design, fabricate, and test a production-scale unit for deployment at the biodiesel production site. Because of its ease of operation, rapid attainment of steady state, high mass transfer and phase separation efficiencies, and compact size, a centrifugal contactor was chosen for intensification of the biodiesel production process. The unit was modified to increase the residence time from a few seconds to minutes*. For this application, liquid phases were introduced into the reactor as separate streams. One was composed of the methanol and base catalyst and the other was the soy oil used in the experiments. Following reaction in the mixing zone, the immiscible glycerine and methyl ester products were separated in the high speed rotor and collected from separate

  13. A COMBINED REACTION/PRODUCT RECOVERY PROCESS FOR THE CONTINUOUS PRODUCTION OF BIODIESEL

    International Nuclear Information System (INIS)

    Oak Ridge National Laboratory (ORNL) and Nu-Energie, LLC entered into a Cooperative Research And Development Agreement (CRADA) for the purpose of demonstrating and deploying a novel technology for the continuous synthesis and recovery of biodiesel from the transesterification of triglycerides. The focus of the work was the demonstration of a combination Couette reactor and centrifugal separator - an invention of ORNL researchers - that facilitates both product synthesis and recovery from reaction byproducts in the same apparatus. At present, transesterification of triglycerides to produce biodiesel is performed in batch-type reactors with an excess of a chemical catalyst, which is required to achieve high reactant conversions in reasonable reaction times (e.g., 1 hour). The need for long reactor residence times requires use of large reactors and ancillary equipment (e.g., feed and product tankage), and correspondingly large facilities, in order to obtain the economy of scale required to make the process economically viable. Hence, the goal of this CRADA was to demonstrate successful, extended operation of a laboratory-scale reactor/separator prototype to process typical industrial reactant materials, and to design, fabricate, and test a production-scale unit for deployment at the biodiesel production site. Because of its ease of operation, rapid attainment of steady state, high mass transfer and phase separation efficiencies, and compact size, a centrifugal contactor was chosen for intensification of the biodiesel production process. The unit was modified to increase the residence time from a few seconds to minutes*. For this application, liquid phases were introduced into the reactor as separate streams. One was composed of the methanol and base catalyst and the other was the soy oil used in the experiments. Following reaction in the mixing zone, the immiscible glycerine and methyl ester products were separated in the high speed rotor and collected from separate

  14. Corrosion product formation during NaCl induced atmospheric corrosion of magnesium alloy AZ91D

    International Nuclear Information System (INIS)

    Magnesium alloy AZ91D was exposed in humid air at 95% relative humidity (RH) with a deposition of 70 μg/cm-2 NaCl. The corrosion products formed and the surface electrolyte were analysed after different exposure times using ex situ and in situ FTIR spectroscopy, X-ray diffraction and Ion Chromatography. The results show that magnesium carbonates are the main solid corrosion products formed under these conditions. The corrosion products identified were the magnesium carbonates hydromagnesite (Mg5 (CO3)4 (OH)24H2O) and nesquehonite (MgCO3 3H2O). The corrosion attack starts with the formation of magnesite at locations with higher NaCl contents. At 95% RH, a sequence of reactions was observed with the initial formation of magnesite, which transformed into nesquehonite after 2-3 days. Long exposures result in the formation of pits containing brucite (Mg(OH2)) covered with hydromagnesite crusts. The hydromagnesite crusts restrict the transport of CO2 and O2 to the magnesium surface and thereby favour the formation of brucite. Analysis of the surface electrolyte showed that the NaCl applied on the surface at the beginning was essentially preserved during the initial corrosion process. Since the applied salt was not bound in sparingly soluble corrosion products a layer of NaCl electrolyte was present on the surface during the whole exposure. Thus, Na+ and Cl- ions can participate in the corrosion process during the whole time and the availability of these species will not restrict the atmospheric corrosion of AZ91D under these conditions. It is suggested that the corrosion behaviour of AZ91D is rather controlled by factors related to the microstructure of the alloy and formation of solid carbonate containing corrosion products blocking active corrosion sites on the surface

  15. Corrosion product formation during NaCl induced atmospheric corrosion of magnesium alloy AZ91D

    Energy Technology Data Exchange (ETDEWEB)

    Joensson, Martin [Corrosion and Metals Research Institute (KIMAB), Drottning Kristinas vaeg 48, SE-114 28 Stockholm (Sweden)]. E-mail: martin.jonsson@kimab.com; Persson, Dan [Corrosion and Metals Research Institute (KIMAB), Drottning Kristinas vaeg 48, SE-114 28 Stockholm (Sweden); Thierry, Dominique [Institut de la Corrosion, 220 Rue Rivoalon, 29200 Brest (France)

    2007-03-15

    Magnesium alloy AZ91D was exposed in humid air at 95% relative humidity (RH) with a deposition of 70 {mu}g/cm{sup -2} NaCl. The corrosion products formed and the surface electrolyte were analysed after different exposure times using ex situ and in situ FTIR spectroscopy, X-ray diffraction and Ion Chromatography. The results show that magnesium carbonates are the main solid corrosion products formed under these conditions. The corrosion products identified were the magnesium carbonates hydromagnesite (Mg{sub 5} (CO{sub 3}){sub 4} (OH){sub 2}4H{sub 2}O) and nesquehonite (MgCO{sub 3} 3H{sub 2}O). The corrosion attack starts with the formation of magnesite at locations with higher NaCl contents. At 95% RH, a sequence of reactions was observed with the initial formation of magnesite, which transformed into nesquehonite after 2-3 days. Long exposures result in the formation of pits containing brucite (Mg(OH{sub 2})) covered with hydromagnesite crusts. The hydromagnesite crusts restrict the transport of CO{sub 2} and O{sub 2} to the magnesium surface and thereby favour the formation of brucite. Analysis of the surface electrolyte showed that the NaCl applied on the surface at the beginning was essentially preserved during the initial corrosion process. Since the applied salt was not bound in sparingly soluble corrosion products a layer of NaCl electrolyte was present on the surface during the whole exposure. Thus, Na{sup +} and Cl{sup -} ions can participate in the corrosion process during the whole time and the availability of these species will not restrict the atmospheric corrosion of AZ91D under these conditions. It is suggested that the corrosion behaviour of AZ91D is rather controlled by factors related to the microstructure of the alloy and formation of solid carbonate containing corrosion products blocking active corrosion sites on the surface.

  16. Kinetic regimes and limiting cases of gas uptake and heterogeneous reactions in atmospheric aerosols and clouds: a general classification scheme

    Directory of Open Access Journals (Sweden)

    T. Berkemeier

    2013-01-01

    Full Text Available Heterogeneous reactions are important to atmospheric chemistry and are therefore an area of intense research. In multiphase systems such as aerosols and clouds, chemical reactions are usually strongly coupled to a complex sequence of mass transport processes and results are often not easy to interpret.

    Here we present a systematic classification scheme for gas uptake by aerosol or cloud particles which distinguishes two major regimes: a reaction-diffusion regime and a mass-transfer regime. Each of these regimes includes four distinct limiting cases, characterized by a dominant reaction location (surface or bulk and a single rate-limiting process: chemical reaction, bulk diffusion, gas-phase diffusion or mass accommodation.

    The conceptual framework enables efficient comparison of different studies and reaction systems, going beyond the scope of previous classification schemes by explicitly resolving interfacial transport processes and surface reactions limited by mass transfer from the gas phase. The use of kinetic multi-layer models instead of resistor model approaches increases the flexibility and enables a broader treatment of the subject, including cases which do not fit into the strict limiting cases typical of most resistor model formulations. The relative importance of different kinetic parameters such as diffusion, reaction rate and accommodation coefficients in this system is evaluated by a quantitative global sensitivity analysis. We outline the characteristic features of each limiting case and discuss the potential relevance of different regimes and limiting cases for various reaction systems. In particular, the classification scheme is applied to three different data sets for the benchmark system of oleic acid reacting with ozone. In light of these results, future directions of research needed to elucidate the multiphase chemical kinetics in this and other reaction systems are discussed.

  17. Kinetic regimes and limiting cases of gas uptake and heterogeneous reactions in atmospheric aerosols and clouds: a general classification scheme

    Directory of Open Access Journals (Sweden)

    T. Berkemeier

    2013-07-01

    Full Text Available Heterogeneous reactions are important to atmospheric chemistry and are therefore an area of intense research. In multiphase systems such as aerosols and clouds, chemical reactions are usually strongly coupled to a complex sequence of mass transport processes and results are often not easy to interpret. Here we present a systematic classification scheme for gas uptake by aerosol or cloud particles which distinguishes two major regimes: a reaction-diffusion regime and a mass transfer regime. Each of these regimes includes four distinct limiting cases, characterised by a dominant reaction location (surface or bulk and a single rate-limiting process: chemical reaction, bulk diffusion, gas-phase diffusion or mass accommodation. The conceptual framework enables efficient comparison of different studies and reaction systems, going beyond the scope of previous classification schemes by explicitly resolving interfacial transport processes and surface reactions limited by mass transfer from the gas phase. The use of kinetic multi-layer models instead of resistor model approaches increases the flexibility and enables a broader treatment of the subject, including cases which do not fit into the strict limiting cases typical of most resistor model formulations. The relative importance of different kinetic parameters such as diffusion, reaction rate and accommodation coefficients in this system is evaluated by a quantitative global sensitivity analysis. We outline the characteristic features of each limiting case and discuss the potential relevance of different regimes and limiting cases for various reaction systems. In particular, the classification scheme is applied to three different datasets for the benchmark system of oleic acid reacting with ozone in order to demonstrate utility and highlight potential issues. In light of these results, future directions of research needed to elucidate the multiphase chemical kinetics in this and other reaction systems

  18. Accumulation of Maillard reaction products in skin collagen in diabetes and aging.

    OpenAIRE

    Dyer, D G; Dunn, J A; Thorpe, S R; Bailie, K E; Lyons, T. J.; McCance, D. R.; Baynes, J W

    1993-01-01

    To investigate the contribution of glycation and oxidation reactions to the modification of insoluble collagen in aging and diabetes, Maillard reaction products were measured in skin collagen from 39 type 1 diabetic patients and 52 nondiabetic control subjects. Compounds studied included fructoselysine (FL), the initial glycation product, and the glycoxidation products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine, formed during later Maillard reactions. Collagen-linked fluorescence...

  19. Minimizing the Entropy Production of the Methanol Producing Reaction in a Methanol Reactor

    OpenAIRE

    Kjelstrup, Signe; Bedeaux, Dick; Johannessen, Eivind; Rosjorde, Audun; Nummedal, Lars

    2000-01-01

    The entropy production of the reaction that produces methanol in a methanol reactor, has been minimized. The results show that the entropy production of the reaction can be reduced by more than 70%. The optimal path through the reactor is characterized by a driving force for the chemical reaction that is close to constant. The entropy production due to heat transfer across the reactor walls in this state is large, however. Variations of the reactor design show that it is possible to accomplis...

  20. Direct estimation of the rate constant of the reaction ClO + HO2 → HOCl + O2 from SMILES atmospheric observations

    Directory of Open Access Journals (Sweden)

    K. Kuribayashi

    2013-05-01

    Full Text Available Diurnal variations of ClO, HO2, and HOCl were simultaneously observed by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES between 12 October 2009 and 21 April 2010. These were the first global observations of the diurnal variation of HOCl in the upper atmosphere. A major reaction to produce HOCl is ClO + HO2 → HOCl + O2 (R1 in extra polar region. A model study suggested that in the mesosphere during night this is the only reaction influencing the amount of HOCl and ClO. The evaluation of the pure reaction period, where only reaction (R1 occurred in Cly chemical system, was performed by the consistency between two reaction rates, HOCl production and ClO loss, from SMILES observation data. It turned out that the SMILES data at the pressure level of 0.28 hPa (about 58 km during night (between local time 18:30 and 04:00 in the autumn mid-latitude region (20–40° February–April 2010 were suitable for the estimation of k1. The rate constant was obtained to be k1(245 K = 7.73 ± 0.26 (1σ [× 10–12 cm3/molecule s] from SMILES atmospheric observations. This result was consistent with that from both the laboratory experiment and the ab initio calculations for similar low-pressure conditions. The 1σ precision of k1 obtained was 2–10 times better than those of previous laboratory measurements.

  1. Gas-phase and particulate products from the atmospheric degradation of the organothiophosphorus insecticide chlorpyrifos-methyl.

    Science.gov (United States)

    Borrás, Esther; Tortajada-Genaro, Luis Antonio; Ródenas, Milagros; Vera, Teresa; Coscollá, Clara; Yusá, Vicent; Muñoz, Amalia

    2015-11-01

    The phosphorothioate structure is highly present in several organophosphorus pesticides. However, there is insufficient information about its degradation process after the release to the atmosphere and the secondary pollutants formed. Herein, the atmospheric reaction of chlorpyrifos-methyl (o,o-dimethyl o-(3,5,6-trichloropyridin-2-yl) phosphorothioate), is described for semi-urban or rural locations. The photo-oxidation under low NOx conditions (5-55 ppbV) was reproduced in a large outdoor simulation chamber, observing a rapid degradation (lifetime<3.5 h). The formation of gaseous products and particulate matter (aerosol yield 2-8%) was monitored. The chemical composition of minor products (gaseous and particulate) was studied, identifying 15 multi-oxygenated derivatives. The most abundant products were ring-retaining molecules such as o,o-dimethyl o-(3,5,6-trichloropyridin-2-yl) phosphorothioate, dimethyl 3,5,6-trichloropyridin-2-yl phosphate, o-methyl o-(3,5,6-trichloropyridin-2-yl) hydrogen phosphorothioate, 3,5,6-trichloropyridin-2-yl dihydrogen phosphate, 3,5,6-trichloropyridin-2-ol, and 3,5,6-trichloropyridine-2,4-diol. An atmospheric degradation mechanism has been proposed based on an oxidation started with OH-nucleophilic attack to P=S bond. The results have been extrapolated to other organothiophosphorus molecules, such as malathion, parathion, diazinon and methidathion, among many others, to estimate their photo-oxidative degradation and the expected products. PMID:25548033

  2. Characterization of the reaction product of the oriT nicking reaction catalyzed by Escherichia coli DNA helicase I.

    OpenAIRE

    Matson, S W; Nelson, W. C.; Morton, B. S.

    1993-01-01

    DNA helicase I, encoded on the Escherichia coli F plasmid, catalyzes a site- and strand-specific nicking reaction within the F plasmid origin of transfer (oriT) to initiate conjugative DNA strand transfer. The product of the nicking reaction contains a single phosphodiester bond interruption as determined by single-nucleotide resolution mapping of both sides of the nick site. This analysis has demonstrated that the nick is located at precisely the same site previously shown to be nicked in vi...

  3. Chemical Characterization and Reactivity Testing of Fuel-Oxidizer Reaction Product (Test Report)

    Science.gov (United States)

    1996-01-01

    The product of incomplete reaction of monomethylhydrazine (MMH) and nitrogen tetroxide (NTO) propellants, or fuel-oxidizer reaction product (FORP), has been hypothesized as a contributory cause of an anomaly which occurred in the chamber pressure (PC) transducer tube on the Reaction Control Subsystem (RCS) aft thruster 467 on flight STS-51. A small hole was found in the titanium-alloy PC tube at the first bend below the pressure transducer. It was surmised that the hole may have been caused by heat and pressure resulting from ignition of FORP. The NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) was requested to define the chemical characteristics of FORP, characterize its reactivity, and simulate the events in a controlled environment which may have lead to the Pc-tube failure. Samples of FORP were obtained from the gas-phase reaction of MMH with NTO under laboratory conditions, the pulsed firings of RCS thrusters with modified PC tubes using varied oxidizer or fuel lead times, and the nominal RCS thruster firings at WSTF and Kaiser-Marquardt. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), accelerating rate calorimetry (ARC), ion chromatography (IC), inductively coupled plasma (ICP) spectrometry, thermogravimetric analysis (TGA) coupled to FTIR (TGA/FTIR), and mechanical impact testing were used to qualitatively and quantitatively characterize the chemical, thermal, and ignition properties of FORP. These studies showed that the composition of FORP is variable but falls within a limited range of compositions that depends on the fuel loxidizer ratio at the time of formation, composition of the post-formation atmosphere (reducing or oxidizing), and reaction or postreaction temperature. A typical composition contains methylhydrazinium nitrate (MMHN), ammonium nitrate (AN), methylammonium nitrate (MAN), and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. The thermal decomposition

  4. Quantum mechanical investigation of the atmospheric reaction CH3O2 + NO.

    Science.gov (United States)

    Lesar, Antonija; Hodoscek, Milan; Drougas, Evangelos; Kosmas, Agnie M

    2006-06-29

    The important stationary points on the potential energy surface of the reaction CH(3)O(2) + NO have been investigated using ab initio and density functional theory techniques. The optimizations were carried out at the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of theory while the energetics have been refined using the G2MP2, G3//B3LYP, and CCSD(T) methodologies. The calculations allow the proper characterization of the transition state barriers that determine the fate of the nascent association conformeric minima of methyl peroxynitrite. The main products, CH(3)O + NO(2), are formed through either rearrangement of the trans-conformer to methyl nitrate and its subsequent dissociation or via the breaking of the peroxy bond of the cis-conformer to CH(3)O + NO(2) radical pair. The important consequences of the proposed mechanism are (a) the allowance on energetic grounds for nitrate formation parallel to radical propagation under favorable external conditions and (b) the confirmation of the conformational preference of the homolytic cleavage of the peroxy bond, discussed in previous literature. PMID:16789778

  5. Research on OH(A) Production Mechanism of an Atmospheric He-Water Plasma Jet

    Science.gov (United States)

    Liu, Jingjing; Hu, Xiao

    2015-09-01

    Hydroxyl radicals produced by atmospheric liquid containing plasmas play important role on bacteria killing and wound healing. A He-H2O plasma jet can produce abundant OH radicals with low gas temperature. At present, some possible reactions to produce OH(A) are concluded, however, the main mechanism to produce OH(A) and the influence of plasma working mode and water vapor concentration on OH(A) generation are still not clear. It is generally regarded that the accurate measurements of electron density and electron temperature play key role on the analysis of OH production mechanism. In this paper, the main generation and loss mechanisms of OH(A) will be found out by both experimental measurements of time-spatial distribution of OH(A) emission intensity, electron density and electron temperature and neutral gas/plasma fluid simulation at different working modes and water vapor concentrations. The influence of plasma working mode and water vapor concentration on OH(A) production and its flux arriving on the substrate is also investigated to optimize the He-H2O plasma jet for bio-medical application.

  6. Modeling of the production of secondary gaseous products in confined atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Courtey, Sylvain; Blondeau, Patrice; Allard, Francis [Laboratoire d' etude des phenomenes de transfert appliques au batiment (LEPTAB), Universite de La Rochelle, pole sciences et technologie, avenue Michel Crepeau, 17042 La Rochelle cedex 1 (France); Jouandon, Eric [Direction Generale de l' Armement (DGA) Centre Technique des Systemes Navals (CTSN), Site du Mourillon, BP 43, 83800 Toulon Armees (France)

    2009-07-15

    Confined environments are indoor spaces in which the air is not renewed or very poorly renewed by fresh outdoor air (spacecraft, submarines, etc.). In these environments, indoor air quality (IAQ) is expected to be highly influenced by homogeneous and heterogeneous chemistry. This paper presents a representative example of the contribution of these two phenomena to the production of secondary gaseous pollutants indoors by analyzing the chemical degradation of isoprene. An indoor air quality model was developed in the Matlab environment to compute the concentrations of both organic and nonorganic gaseous species involved in this mechanism. Two kinds of initial conditions (concentrations of nitrogen oxides, ozone and isoprene) were considered for the simulations. The results show strong interactions between homogeneous and heterogeneous reactions. Especially, the integrated reaction rate (IRR) of the heterogeneous hydrolysis of nitrogen dioxide emerges very high. Demonstration of strong interactions between inorganic and organic chemistries is also made, the conversion between NO and NO{sub 2} being of central importance in the degradation cycle of isoprene. The type and amount of secondary products obtained are assessed. The results emphasize the strong influence of ozone and nitric oxide concentration levels indoors. (author)

  7. Mechanistic studies of NO{sub x} reduction reactions under oxidative atmosphere on alumina supported 0.2wt% platinum catalyst treated under microwave. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Ringler, Sandrine; Girard, Paule; Maire, Gilbert; Garin, Francois [Laboratoire d`Etudes de la Reactivite Catalytique, des Surfaces et Interfaces (LERCSI), UMR 7515 du CNRS - ECPM, Universite Louis Pasteur - Institut Le Bel 4, rue Blaise Pascal 67, 070 Strasbourg Cedex (France); Hilaire, Stephanie; Roussy, Georges [Laboratoire de Spectroscopie et des Techniques Micro-Ondes LSTM, Universite de Nancy I, BP 239 54506, Vandoeuvre-les-Nancy Cedex (France)

    1999-03-08

    Reduction of nitrogen oxides under oxidative atmosphere is a very extensively studied reaction, but it is still very difficult to understand and to follow the various pathways of the reaction. Two alumina supported 0.2wt% platinum catalysts, reduced by hydrogen in an oven heated either by microwave irradiations or by Joule effect, with different metal dispersion of 60% and 90%, respectively, were studied. By the use of labelled compounds we were able to show the presence of an exchange reaction between 15N16O and 15N18O which occurred on both catalysts. It means that [15N16O18O] is the intermediate species. Such product, 15N18O, is less formed on the microwave catalyst `MW` than on the classical one `CT`. Experiments were performed at 22 and 550Torr, between 150C and 250C. Near atmospheric pressure, `MW` catalyst gives higher initial rates for 15N{sub 2} formation than the `CT` catalysts. At low temperature, the nitrogen selectivity is higher on `MW` catalyst than on the other catalyst. From the apparent activation energy values, one may deduce that several mechanisms are responsible for the 15N{sub 2} formation depending on the reaction temperature and the catalyst used. On the 0.2% Pt/Al{sub 2}O{sub 3} `CT` catalyst, an additive process between propene and 15NO takes place at low temperature giving nitroso and oxime intermediate species. At high temperature, a partial oxidation of propene occurs, giving a ketone, before the 15NO reduction to 15N{sub 2}. With this catalyst only two sites with different activity are involved. On the 0.2% Pt/Al{sub 2}O{sub 3} `MW` catalyst the reactants are seated on three sites with different activity. This particularity reinforce the proposals concerning the `MW` catalyst which may exhibit particular shapes for the aggregates having different crystallographic orientations. What is surprising, for this `MW` catalyst, is the fact that we already observed a specific reactivity under reductive atmosphere in reforming reactions and now

  8. Proposed Evaluation of Monitor and Radioisotope Production Reactions

    International Nuclear Information System (INIS)

    The DDHMS (Double Differential Hybrid Monte-Carlo Simulation) model provides a suitable method for the calculation of multiple pre-equilibrium emission cross sections in γ or nucleon-induced reactions. ITA staff have extended this approach to produce exclusive cross sections, and have adopted a more appropriate Monte-Carlo sampling procedure to furnish a simplified, semi-classical version of the Feshbach-Kerman-Koonin multistep direct reaction model. Work continues to improve the physical content of the model, of which one aim is to describe the reactions in terms of the DDHMS method within the EMPIRE code.

  9. Critical Evaluation of Chemical Reaction Rates and Collision Cross Sections of Importance in the Earth's Upper Atmosphere and the Atmospheres of Other Planets, Moons, and Comets

    Science.gov (United States)

    Huestis, David L.

    2006-01-01

    We propose to establish a long-term program of critical evaluation by domain experts of the rates and cross sections for atomic and molecular processes that are needed for understanding and modeling the atmospheres in the solar system. We envision data products resembling those of the JPL/NASA Panel for Data Evaluation and the similar efforts of the international combustion modeling community funded by US DoE and its European counterpart.

  10. Products and Mechanisms of Aerosol Formation from Reactions of OH Radicals with Linear and Branched Alkenes in the Presence of NOx (Invited)

    Science.gov (United States)

    Ziemann, P. J.; Matsunaga, A.

    2009-12-01

    The chemical and physical processes involved in the formation of secondary organic aerosol (SOA) are complex and can include reactions of volatile organic compounds with a number of atmospheric oxidants (the major ones are O3, and OH and NO3 radicals), as well as surface and condensed-phase reactions, homogeneous nucleation, and gas-particle partitioning. It should come as no surprise that understanding and accurately modeling these processes is a major challenge that has not yet been fully addressed. Alkenes emitted from vegetation are the largest source of non-methane hydrocarbons to the global atmosphere and consist mostly of isoprene (C5H8), monoterpenes (C10H16), and sesquiterpenes (C15H24), compounds with a large range of sizes and molecular structures. Their atmospheric oxidation is initiated primarily by reactions with hydroxyl radicals and can lead to a variety of products, some of which can form SOA. Because of the complexity of terpene reactions and the large numbers of products that are formed, there are advantages to studying the chemistry of simpler alkenes in order to gain insights that can be applied to more complex reaction systems. This is the approach we have taken, and in this talk I will report results of studies of the products, SOA yields, and mechanisms of SOA formation from reactions of a variety of linear and branched alkenes with hydroxyl radicals in the presence of nitrogen oxides. Products consist of a large array of multifunctional compounds, including oligomers, containing carbonyl, hydroxy, carboxyl, and nitrate groups. I will demonstrate some of the ways in which changes in molecular structure can alter both gas and SOA products, including those formed through condensed-phase reactions, and also SOA yields, and suggest explanations for these effects based on current understanding of chemical reaction mechanisms.

  11. Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water

    Science.gov (United States)

    Ota, K.; Conger, W. L.

    1977-01-01

    The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

  12. Atmospheric heteroseneous reaction of acetone: Adsorption and desorption kinetics and mechanisms on SiO2 particles

    Institute of Scientific and Technical Information of China (English)

    JIE ChongYu; CHEN ZhongMing; WANG HongLi; HUA Wei; WANG CaiXia; LI Shuang

    2008-01-01

    Acetone plays an important role in photooxidation processes in the atmosphere. Up to date, little is known regarding the heterogeneous fate of acetone. In this study, the adsorption and desorption processes of acetone on SiO2 particles, which are the major constituent of mineral dust in the atmos-phere, have been investigated for the first time under the simulated atmospheric conditions, using in situ transmission Fourier transform infrared spectroscopy. It is found that acetone molecules are ad-sorbed on the surfaces of SiO2 particles by van der Waals forces and hydrogen bonding forces in a nonreactive and reversible state. The rates of initial adsorption and initial desorption, initial uptake coefficients and adsorption concentrations at equilibrium have been determined at different relative humidity. The presence of water vapor cannot result in the formation of new substances, but can de-crease the adsorption ability by consuming or overlapping the isolated OH groups on the surfaces of SiO2 particles. In the desorption process, a considerable amount of acetone molecules will remain on SiO2 particles in dry air, whereas acetone molecules are almost completely desorbed at a high relative humidity. In order to evaluate the role of heterogeneous reactions of acetone and other carbonyl compounds in the atmosphere, a new model fitting the atmospheric conditions is needed.

  13. Free-radical production and oxidative reactions of hemoglobin.

    OpenAIRE

    Winterbourn, C C

    1985-01-01

    Mechanisms of autoxidation of hemoglobin, and its reactions with H2O2, O2-, and oxidizing or reducing xenobiotics are discussed. Reactive intermediates of such reactions can include drug free radicals, H2O2, and O2-, as well as peroxidatively active ferrylhemoglobin and methemoglobin-H2O2. The contributions of these species to hemoglobin denaturation and drug-induced hemolysis, and the actions of various protective agents, are considered.

  14. Processing of Aluminum Alloys Containing Displacement Reaction Products

    OpenAIRE

    Stawovy, Michael Thomas

    1998-01-01

    Aluminum and metal-oxide powders were mixed using mechanical alloying. Exothermic displacement reactions could be initiated in the powders either by mechanical alloying alone or by heat treating the mechanically alloyed powders. Exponential relationships developed between the initiation time of the reaction and the mechanical alloying charge ratio. The exponential relationships were the result of changes in the intensity and quantity of collisions occurring during mechanical alloying. Di...

  15. Food Processing and Maillard Reaction Products: Effect on Human Health and Nutrition

    OpenAIRE

    Nahid Tamanna; Niaz Mahmood

    2015-01-01

    Maillard reaction produces flavour and aroma during cooking process; and it is used almost everywhere from the baking industry to our day to day life to make food tasty. It is often called nonenzymatic browning reaction since it takes place in the absence of enzyme. When foods are being processed or cooked at high temperature, chemical reaction between amino acids and reducing sugars leads to the formation of Maillard reaction products (MRPs). Depending on the way the food is being processed,...

  16. Atmospheric hydroxyl radical production from electronically excited NO2 and H2O.

    Science.gov (United States)

    Li, Shuping; Matthews, Jamie; Sinha, Amitabha

    2008-03-21

    Hydroxyl radicals are often called the "detergent" of the atmosphere because they control the atmosphere's capacity to cleanse itself of pollutants. Here, we show that the reaction of electronically excited nitrogen dioxide with water can be an important source of tropospheric hydroxyl radicals. Using measured rate data, along with available solar flux and atmospheric mixing ratios, we demonstrate that the tropospheric hydroxyl contribution from this source can be a substantial fraction (50%) of that from the traditional O(1D) + H2O reaction in the boundary-layer region for high solar zenith angles. Inclusion of this chemistry is expected to affect modeling of urban air quality, where the interactions of sunlight with emitted NOx species, volatile organic compounds, and hydroxyl radicals are central in determining the rate of ozone formation. PMID:18356524

  17. Dynamical Effects and Product Distributions in Simulated CN + Methane Reactions.

    Science.gov (United States)

    Preston, Thomas J; Hornung, Balázs; Pandit, Shubhrangshu; Harvey, Jeremy N; Orr-Ewing, Andrew J

    2016-07-14

    Dynamics of collisions between structured molecular species quickly become complex as molecules become large. Reactions of methane with halogen and oxygen atoms serve as model systems for polyatomic molecule chemical dynamics, and replacing the atomic reagent with a diatomic radical affords further insights. A new, full-dimensional potential energy surface for collisions between CN + CH4 to form HCN + CH3 is developed and then used to perform quasi-classical simulations of the reaction. Coupled-cluster energies serve as input to an empirical valence bonding (EVB) model, which provides an analytical function for the surface. Efficient sampling permits simulation of velocity-map ion images and exploration of dynamics over a range of collision energies. Reaction populates HCN vibration, and energy partitioning changes with collision energy. The reaction cross-section depends on the orientation of the diatomic CN radical. A two-dimensional extension of the cone of acceptance for an atom in the line-of-centers model appropriately describes its reactivity. The simulation results foster future experiments and diatomic extensions to existing atomic models of chemical collisions and reaction dynamics. PMID:26812395

  18. Carbon dioxide sequestration via olivine carbonation: Examining the formation of reaction products

    Science.gov (United States)

    King, H. E.; Plümper, O.; Putnis, A.

    2009-04-01

    Due to its abundance and natural ability to sequester CO2, olivine has been proposed as one mineral that could be used in the control of CO2 emissions into the atmosphere (Metz, 2005). Large scale peridotite deposits found in locations such as the Western Gneiss Region in Norway could provide in-situ sites for sequestration or the raw materials for ex-situ mineral carbonation. Determining the conditions under which magnesite (MgCO3) forms most efficiently is crucial to conduct a cost effective process. Understanding the development of secondary minerals is particularly important for in-situ methods as these phases can form passivating layers and affect the host rock porosity. The final solution of flow-through experiments conducted at alkaline pH have been shown to be supersaturated with respect to talc and chrysotile (Giammer et al., 2005), although these phases were not found to have precipitated the formation of a passivating, amorphous silica layer has been observed on reacted olivine surfaces (Bearat et al., 2006). By studying magnesite and other products produced during the carbonation of olivine within Teflon lined steel autoclaves we have begun to form a more comprehensive understanding of how these reactions would proceed during sequestration processes. We have performed batch experiments using carbonated saline solutions in the presence of air or gaseous CO2 from 80 to 200 ˚ C. X-ray powder diffraction was used to identify magnesite within the reaction products. Crystals of magnesite up to 20 m in diameter can be observed on olivine grain surfaces with scanning electron microscopy. Secondary reaction products formed a platy layer on olivine surfaces in reactions above 160 ˚ C and below pH 12. Energy dispersive X-ray analysis of the platy layer revealed an increase in Fe concentration. The macroscopically observable red colouration of the reaction products and Raman spectroscopy indicate that hematite is present in these layers. For experiments with

  19. Variations in product in reactions of naphthoquinone with primary amines

    OpenAIRE

    Barooah Nilotpal; Karmakar Anirban; Singh Marjit W; Baruah Jubaraj B

    2007-01-01

    Abstract Reaction of 1,2-naphthoquinone with primary amines gives a 2-amino-1,4-naphthoquinone derivative which is equivalent to 1,2 to 1,4 carbonyl transposition. For example the reaction of 1,2-naphthoquinone with 4-methoxyaniline gives 2-(4-methoxyanilino)-naphthoquinone-1,4-(4-methoxyanil) (1) and with n-butylamine gives 2-(butylamino)-naphthoquinone-1,4-butylimine (2) respectively. The compounds 1 and 2 are characterized by X-ray crystallography; they have hydrogen-bonded dimeric structu...

  20. Comparison of Complementary Reactions in the Production of Mt

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Sarah; Gregorich, Kenneth; Dragojevic, Irena; Ellison, Paul; Garcia, Mitch Andre; Gates, Jacklyn; Stavsetra, Liv; Ali, Mazhar; Nitsche, Heino

    2009-01-21

    The new reaction 208Pb(59Co,n)266Mt was studied using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. A cross section of 7.7+5.2-3.3 pb was measured at a compound nucleus excitation energy of 14.9 MeV. The measured decay properties of 266Mt and its daughters correspond well with existing data. We compare this experimental result to transactinide compound nucleus formation model predictions, and the previously studied 209Bi(58Fe,n)266Mt reaction.

  1. Isotope production for medical usage using fast neutron reactions

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Y.; Nagai, Y.; Kin, T. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan)] [and others

    2011-07-01

    {sup 99}Mo was produced by the {sup 100}Mo(n, 2n){sup 99}Mo reaction using 14-MeV neutrons from the D({sup 3}H, n){sup 4}He reaction at Fusion Neutronics Source Facility (FNS) at JAEA. A target of titanium oxide gel with molybdenum oxide was irradiated and used as the {sup 99m}Tc/{sup 99}Mo generator. The growth curve of 99mTc in the titanium gel target and the elution curve of {sup 99m}Tc from the {sup 99}Mo/{sup 99m}Tc generator were obtained. (orig.)

  2. Evaluated kinetic and photochemical data for atmospheric chemistry: Volume V – heterogeneous reactions on solid substrates

    Directory of Open Access Journals (Sweden)

    J. N. Crowley

    2010-09-01

    Full Text Available This article, the fifth in the ACP journal series, presents data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the heterogeneous processes on surfaces of solid particles present in the atmosphere, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website in 2010. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. Four substantial appendices contain detailed data sheets for each process considered for ice, mineral dust, sulfuric acid hydrate and nitric acid hydrate surfaces, which provide information upon which the recommendations are made.

  3. Oxidation kinetics of reaction products formed in uranium metal corrosion

    International Nuclear Information System (INIS)

    The oxidation behavior of uranium metal ZPPR fuel corrosion products in environments of Ar-4%O2 and Ar-20%O2 were studied using thermo-gravimetric analysis (TGA). These tests were performed to extend earlier work in this area specifically, to assess plate-to-plate variations in corrosion product properties and the effect of oxygen concentration on oxidation behavior. The corrosion products from two relatively severely corroded plates were similar, while the products from a relatively intact plate were not reactive. Oxygen concentration strongly affected the burning rate of reactive products, but had little effect on low-temperature oxidation rates

  4. HYDROTHERMAL REACTIONS OF CORROSION PRODUCTS IN REACTOR PRIMARY CONDITIONS

    Czech Academy of Sciences Publication Activity Database

    Zmítko, M.; Grygar, Tomáš; Štengl, Václav; Šubrt, Jan; Kláriková, Adriana

    Kashiwazaki : JAIF, 1998, s. 707-714 [1998 JAIF International Conference on Water Chemistry in Nuclear Power Plants. Kashiwazaki (JP), 13.10.1998-16.10.1998] Institutional research plan: CEZ:AV0Z4032918 Keywords : VVER reactors * iron oxides * hydrothermal reactions Subject RIV: CA - Inorganic Chemistry

  5. Utility of spectral measurements of secondary reaction products

    Energy Technology Data Exchange (ETDEWEB)

    Heidbrink, W.E.

    1986-02-01

    The spectra of 15 MeV protons and 14 MeV neutrons produced in the burnup of 0.8 MeV THe ions and 1 MeV tritons through the d(THe,p) and d(t,n) fusion reactions contain information on the velocity distributions of the energetic THe ions and tritons. 11 refs., 2 figs.

  6. Protonation Reaction of Benzonitrile Radical Anion and Absorption of Product

    DEFF Research Database (Denmark)

    Holcman, Jerzy; Sehested, Knud

    1975-01-01

    The rate constant for the protonation of benzonitrile radical anions formed in pulse radiolysis of aqueous benzonitrile solutions is (3.5 ± 0.5)× 1010 dm3 mol–1 s–1. A new 270 nm absorption band is attributed to the protonated benzonitrile anion. The pK of the protonation reaction is determined to...

  7. Experimental study on the effect of low melting point metal additives on hydrogen production in the aluminum–water reaction

    International Nuclear Information System (INIS)

    Aluminum (Al) is a promising hydrogen carrier. Continuous reaction of pure Al and water (H2O) cannot proceed smoothly because Al particles are covered with a protective oxide layer. Thus, 20% Mg, Li, Zn, Bi, and Sn content were added as additives to Al–H2O reaction at high temperature. Thermogravimetric experiments were conducted to determine the reactivity of pure Al and five other samples with additives in a vapor atmosphere. Experiments indicated that Mg and Li drove the Al–H2O reaction, but Zn, Bi, and Sn had little effect. Thus, Mg and Li were selected as activators in the hydrogen generation of the Al–H2O reaction conducted on a specially designed experimental facility. Hydrogen was monitored in the reaction of Al-based composites with H2O vapor in real time. Among them, Al–20%Li achieved the fastest hydrogen generation rate (309.74 ml s−1 g−1) and the largest hydrogen amount (1038.9 ml g−1). XRD (X-ray diffraction), SEM (scanning electron microscopy), and TEM (transmission electron microscopy) were used for product analyses to identify the influence of adding Mg and Li. This method of Al energy utilization may be used in underwater propulsion systems. - Highlights: • In this paper, we discussed a way of hydrogen production by the reaction of molten aluminum with water. • 20% Mg, Li, Zn, Bi, and Sn content were added as additives to Al–H2O reaction at high temperature. • Al–20%Li achieved the fastest hydrogen generation rate and the largest hydrogen amount

  8. The role of oxygen and surface reactions in the deposition of silicon oxide like films from HMDSO at atmospheric pressure

    OpenAIRE

    Reuter, R; Rügner, K.; Ellerweg, D.; Arcos, T. de los; von Keudell, A.; Benedikt, J

    2011-01-01

    The deposition of thin SiO$_x$C$_y$H$_z$ or SiO$_x$H$_y$ films by means of atmospheric pressure microplasma jets with admixture of Hexamethyldisiloxane (HMDSO) and oxygen and the role of surface reactions in film growth are investigated. Two types of microplasma jets, one with a planar electrodes and operated in helium gas and the other one with a coaxial geometry operated in argon, are used to study the deposition process. The growth rate of the film and the carbon-content in the film are me...

  9. Safety assessment of Maillard reaction products of chicken bone hydrolysate using Sprague-Dawley rats

    OpenAIRE

    ZHANG, CHUNHUI; Wang, Jin-Zhi; Sun, Hong-Mei; Hu, Li; Li, Xia; Wu, Xiao-Wei

    2016-01-01

    Background: The Maillard reaction products of chicken bone hydrolysate (MRPB) containing 38% protein, which is a derived product from chicken bone, is usually used as a flavor enhancer or food ingredient. In the face of a paucity of reported data regarding the safety profile of controversial Maillard reaction products, the potential health effects of MRPB were evaluated in a subchronic rodent feeding study.Methods: Sprague–Dawley rats (SD, 5/sex/group) were administered diets containing 9, 3,...

  10. The Moessbauer spectroscopy in the characterization of atmospheric corrosion products

    International Nuclear Information System (INIS)

    A study of corrosion products on mild steel formed after 1 and 5 years exposure in two industrial coastal weathering stations in the Bay from Matanzas City, Cuba, has been carried out. Structural analysis was conducted using mainly transmission Moessbauer Spectroscopy and the X-ray diffraction as complementary technique. The main phases found in the specimen exposed to high chloride containing environment were: lepidocrocite (γ- FeOOH), goethite (α- FeOOH) and magnetite concentration was the lowest, the phases found were γ- FeOOH and α- FeOOH, and the phase transformation proposed was γ- FeOOh -> α- Fe-OOH. In this station were found also amorphous corrosion products. There amorphous phases could be responsible for the lowest levels of corrosion on steel in this station

  11. Atmospheric chemistry of CF3O radicals: Reaction with H2O

    DEFF Research Database (Denmark)

    Wallington, T.J.; Hurley, M.D.; Schneider, W.F.;

    1993-01-01

    Evidence is presented that CF3O radicals react with H2O in the gas phase at 296 K to give CF3OH and OH radicals. This reaction is calculated to be exothermic by 1.7 kcal mol-I implying a surprisingly strong CF3O-H bond energy of 120 +/- 3 kcal mol-1. Results from a relative rate experimental stud...... suggest that the rate constant for the reaction of CF3O radicals with H2O lies in the range (0.2-4.0) X 10(-17) cm3 molecule-1 s-1. Implications for the atmospheric chemistry of CF3O radicals are discussed....

  12. Complex signal amplitude analysis for complete fusion nuclear reaction products

    CERN Document Server

    Tsyganov, Yu S

    2015-01-01

    A complex analysis has been performed on the energy amplitude signals corresponding to events of Z=117 element measured in the 249Bk+48Ca complete fusion nuclear reaction. These signals were detected with PIPS position sensitive detector. The significant values of pulse height defect both for recoils (ER) and fission fragments (FF) were measured. Comparison with the computer simulations and empirical formulae has been performed both for ER and FF signals.

  13. Utility of spectral measurements of secondary reaction products

    International Nuclear Information System (INIS)

    The spectra of 15 MeV protons and 14 MeV neutrons produced in the burnup of 0.8 MeV 3He ions and 1 MeV tritons through the d(3He,p)α and d(t,n)α fusion reactions contain information on the velocity distributions of the energetic 3He ions and tritons. 11 refs., 2 figs

  14. Influence of atmospheric nutrients on primary productivity in a coastal upwelling region

    OpenAIRE

    Katherine R.M. Mackey; van Dijken, Gert L.; Mazloom, Simran; Erhardt, Andrea M; Ryan, John; Arrigo, Kevin R; Paytan, Adina

    2010-01-01

    Atmospheric deposition is an important source of nutrients to the coastal and open ocean; however, its role in highly productive upwelling regions like coastal California has not been determined. Approximately 0.1%–0.2% of new production is attributable to atmospheric deposition of nitrogen (N) annually, but if the estimate is expanded to encompass the effects of iron (Fe), aerosols may support 1%–2% of new production on average, and up to 5% on days with high deposition fluxes. Laboratory cu...

  15. Effects of hydrolysis and carbonization reactions on hydrochar production.

    Science.gov (United States)

    Fakkaew, K; Koottatep, T; Polprasert, C

    2015-09-01

    Hydrothermal carbonization (HTC) is a thermal conversion process which converts wet biomass into hydrochar. In this study, a low-energy HTC process named "Two-stage HTC" comprising of hydrolysis and carbonization stages using faecal sludge as feedstock was developed and optimized. The experimental results indicated the optimum conditions of the two-stage HTC to be; hydrolysis temperature of 170 °C, hydrolysis reaction time of 155 min, carbonization temperature of 215 °C, and carbonization reaction time of 100 min. The hydrolysis reaction time and carbonization temperature had a statistically significant effect on energy content of the produced hydrochar. Energy input of the two-stage HTC was about 25% less than conventional HTC. Energy efficiency of the two-stage HTC for treating faecal sludge was higher than that of conventional HTC and other thermal conversion processes such as pyrolysis and gasification. The two-stage HTC could be considered as a potential technology for treating FS and producing hydrochar. PMID:26051497

  16. Effect of synthesis atmosphere on photocatalytic hydrogen production of NaNbO3

    International Nuclear Information System (INIS)

    The NaNbO3 photocatalysts were prepared under air, H2/Ar and O2 atmosphere by a solid state reaction. These samples were characterized by X-ray diffraction, UV–vis spectroscopy, Raman spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The photocatalytic activity of NaNbO3 samples were evaluated from the hydrogen evolution from an aqueous methanol solution. The hydrogen evolution rate of NaNbO3 under air, H2/Ar and O2 atmosphere showed an increasing trend in turn. Moreover, the hydrogen evolution rate exhibited a linear increase with the surface oxygen defects.

  17. PTFE treatment by remote atmospheric Ar/O2 plasmas: a simple reaction scheme model proposal

    OpenAIRE

    Carbone, E. A. D.; Verhoeven, M. W. G. M.; Keuning, W.; van der Mullen, J. J. A. M.

    2013-01-01

    Polytetrafluoroethylene (PTFE) samples were treated by a remote atmospheric pressure microwave plasma torch and analyzed by water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS). In the case of pure argon plasma a decrease of WCA is observed meanwhile an increase of hydrophobicity was observed when some oxygen was added to the discharge. The WCA results are correlated to XPS of reference samples and the change of WCA are attributed to changes in roughness of the samples. A simp...

  18. Low-intensity radiolysis study of free-radical reactions in cloudwater: H2O2 production and destruction

    International Nuclear Information System (INIS)

    Reactions in cloudwater can be important pathways for chemical transformation of atmospheric trace gases. One such reaction is the oxidation of dissolved sulfur dioxide by hydrogen peroxide. H2O2 is formed by the disproportionation of hydroperoxyl and superoxide radicals, O2(-I). The authors report measurements of the rate of H2O2 production from O2(-I) radicals generated by low-intensity cobalt-60 radiolysis of synthetic cloudwater solutions and actual precipitation samples. The authors results, employing O2(-I) production rates comparable to those expected upon transfer of HO2 from interstitial cloud air to cloudwater, confirm model predictions that H2O2 production if frequently the major fate of O2(-I) radicals. However, there is evidence of significant reaction between S(IV) and O2(-I), with a rate coefficient of (3 ± 2) x 104 at pH 4.96. In addition, the presence of 1 μM dissolved iron decreases the H2O2 yield, principally because of destruction of H2O2 by Fe(II)

  19. Minimizing the Entropy Production of the Methanol Producing Reaction in a Methanol Reactor

    OpenAIRE

    Dick Bedeaux; Lars Nummedal; Audun Rosjorde; Eivind Johannessen; Signe Kjelstrup

    2000-01-01

    The entropy production of the reaction that produces methanol in a methanol reactor, has been minimized. The results show that the entropy production of the reaction can be reduced by more than 70%. The optimal path through the reactor is characterized by a driving force for the chemical reaction that is close to constant. The entropy production due to heat transfer across the reactor walls in this state is large, however. Variations of the reactor design show that it is possible to ...

  20. Measurement of fission product gases in the atmosphere

    Science.gov (United States)

    Schell, W. R.; Tobin, M. J.; Marsan, D. J.; Schell, C. W.; Vives-Batlle, J.; Yoon, S. R.

    1997-01-01

    The ability to quickly detect and assess the magnitude of releases of fission-produced radioactive material is of significant importance for ongoing operations of any conventional nuclear power plant or other activities with a potential for fission product release. In most instances, the control limits for the release of airborne radioactivity are low enough to preclude direct air sampling as a means of detection, especially for fission gases that decay by beta or electron emission. It is, therefore, customary to concentrate the major gaseous fission products (krypton, xenon and iodine) by cryogenic adsorption for subsequent separation and measurement. This study summarizes our initial efforts to develop an automated portable system for on-line separation and concentration with the potential for measuring environmental levels of radioactive gases, including 85Kr, 131,133,135Xe, 14C, 3H, 35S, 125,131I, etc., without using cryogenic fluids. Bench top and prototype models were constructed using the principle of heatless fractionation of the gases in a pressure swing system. This method removes the requirement for cryogenic fluids to concentrate gases and, with suitable electron and gamma ray detectors, provides for remote use under automatic computer control. Early results using 133Xe tracer show that kinetic chromatography, i.e., high pressure adsorption of xenon and low pressure desorption of air, using specific types of molecular sieves, permits the separation and quantification of xenon isotopes from large volume air samples. We are now developing the ability to measure the presence and amounts of fission-produced xenon isotopes that decay by internal conversion electrons and beta radiation with short half-lives, namely 131mXe, 11.8 d, 133mXe, 2.2 d, 133Xe, 5.2 d and 135Xe, 9.1 h. The ratio of the isotopic concentrations measured can be used to determine unequivocally the amount of fission gas and time of release of an air parcel many kilometers downwind from a

  1. Investigation on the production of evaporation residues in 11B + natY reaction: 97Ru is a notable product

    International Nuclear Information System (INIS)

    This study indicates that the 11B induced reaction on natural Y is also an efficient route for the production of nca neutron deficient 97Ru. Although cross-sectional data are obtained just at two energies and not sufficient to derive significant conclusion on the reaction mechanism, but the measured cross-sectional data are in agreement with Houser-Feshbach model estimation. The data also shed light on the compound nuclear reaction as a major contributor. We look forward to study the reaction in the energy range ∼30-70 MeV in near future

  2. Study on the atmospheric photochemical reaction of CF3 radicals using ultraviolet photoelectron and photoionization mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A study of the atmospheric photochemical reaction of CF3 radical with CO and O2 was performed by using a homemade ultraviolet photoelectron spectrometer-photoionization mass spectrometer (PES- PIMS). The electronic structures and mechanism of ionization and dissociation of CF3OC(O)OOC(O)- OCF3 were investigated. It was indicated that the two bands on the photoelectron spectrum of CF3OC(O)OOC(O)OCF3 are the result of ionization of an electron from a lone pair of oxygen and a fluo- rine lone pair of CF3 group. The outermost electrons reside in the oxygen lone pair. The experimental and theoretical first vertical ionization energy is 13.21 and 13.178 eV, respectively, with the PES and OVGF method. They are in good agreement. The photo ionization and dissociation processes were discussed with the help of theoretical calculations and PES-PIMS experiment. After ionization, the parent ions prefer the dissociation of the C-O bond and giving the fragments CF3OCO+ and CF3+. It demonstrated that the ultraviolet photoelectron and photoionization mass spectrometer could be ap- plied widely in the study of atmospheric photochemical reaction.

  3. X-ray photoelectron spectroscopic study on surface reaction on titanium by laser irradiation in nitrogen atmosphere

    International Nuclear Information System (INIS)

    The surface reaction on titanium due to pulsed Nd:YAG laser irradiation in a nitrogen atmosphere was investigated using X-ray photoelectron spectroscopy (XPS). The laser, with a wavelength of 532 nm (SHG mode), was irradiated on a titanium substrate in an atmosphere-controlled chamber, and then the substrate was transported to an XPS analysis chamber without exposure to air. This in situ XPS technique makes it possible to clearly observe the intrinsic surface reaction. The characteristics of the surface layer strongly depend on the nitrogen gas pressure. When the pressure is 133 kPa, an oxynitride and a stoichiometric titanium nitride form the topmost and lower surface layers on the titanium substrate, respectively. However, only a nonstoichiometric titanium oxide layer containing a small amount of nitrogen is formed when the pressure is lower than 13.3 kPa. Repetition of laser shots promotes the formation of the oxide layer, but the formation is completed within a few laser shots. After the initial structure is formed, the chemical state of the surface layer is less influenced by the repetition of laser shots.

  4. Optimised procedure to analyse maillard reaction-associated fluorescence in cereal-based products

    OpenAIRE

    Delgado Andrade, Cristina; Rufián Henares, J. A.; Morales, F. J.

    2008-01-01

    Fluorescent Maillard compounds measurement provides more specific information on the extent of the Maillard reaction than other unspecific tools to monitor the reaction, and is suitable, as the first approach, to assess the nutritional quality of foods as related to protein damage. This work presents an optimised laboratory procedure for the measurement of total fluorescent intermediate compounds (FIC) associated with Maillard reaction, described and evaluated in a cereal-based product. Total...

  5. Atmospheric isoprene ozonolysis: impacts of stabilized Criegee intermediate reactions with SO2, H2O and dimethyl sulfide

    Directory of Open Access Journals (Sweden)

    M. J. Newland

    2015-03-01

    Full Text Available Isoprene is the dominant global biogenic volatile organic compound (VOC emission. Reactions of isoprene with ozone are known to form stabilised Criegee intermediates (SCIs, which have recently been shown to be potentially important oxidants for SO2 and NO2 in the atmosphere; however the significance of this chemistry for SO2 processing (affecting sulfate aerosol and NO2 processing (affecting NOx levels depends critically upon the fate of the SCI with respect to reaction with water and decomposition. Here, we have investigated the removal of SO2 in the presence of isoprene and ozone, as a function of humidity, under atmospheric boundary layer conditions. The SO2 removal displays a clear dependence on relative humidity, confirming a significant reaction for isoprene derived SCI with H2O. Under excess SO2 conditions, the total isoprene ozonolysis SCI yield was calculated to be 0.56 (±0.03. The observed SO2 removal kinetics are consistent with a relative rate constant, k(SCI + H2O/k(SCI + SO2, of 5.4 (±0.8 × 10−5 for isoprene derived SCI. The relative rate constant for k(SCI decomposition/k(SCI + SO2 is 8.4 (±5.0 × 1010 cm−3. Uncertainties are ±2σ and represent combined systematic and precision components. These kinetic parameters are based on the simplification that a single SCI species is formed in isoprene ozonolysis, an approximation which describes the results well across the full range of experimental conditions. Our data indicate that isoprene-derived SCIs are unlikely to make a substantial contribution to gas-phase SO2 oxidation in the troposphere. We also present results from an analogous set of experiments, which show a clear dependence of SO2 removal in the isoprene-ozone system as a function of dimethyl sulfide concentration. We propose that this behaviour arises from a rapid reaction between isoprene-derived SCI and DMS; the observed SO2 removal kinetics are consistent with a relative rate constant, k(SCI + DMS/k(SCI + SO2

  6. The effects of reactants ratios, reaction temperatures and times on Maillard reaction products of the L-ascorbic acid/L-glutamic acid system

    Directory of Open Access Journals (Sweden)

    Yong-Yan ZHOU

    2016-01-01

    Full Text Available Abstract The transformation law of the Maillard reaction products with three different reactants ratios - equimolar reactants, excess L-glutamic acid and excess L-ascorbic acid reaction respectively, five different temperatures, and different time conditions for the L-ascorbic acid / L-glutamic acid system were investigated. Results showed that, the increase of the reaction time and temperature led to the increase of the browning products, uncoloured intermediate products, as well as aroma compounds. Compared with the equimolar reaction system, the excess L-ascorbic acid reaction system produced more browning products and uncoloured intermediate products, while the aroma compounds production remained the same. In the excess L-glutamic acid system, the uncoloured intermediate products increased slightly, the browning products remained the same, while the aroma compounds increased.

  7. Reactions of 3-Formylchromone with Active Methylene and Methyl Compounds and Some Subsequent Reactions of the Resulting Condensation Products

    Directory of Open Access Journals (Sweden)

    M. Lácova

    2005-08-01

    Full Text Available This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the γ-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted.

  8. Reactions of 3-formylchromone with active methylene and methyl compounds and some subsequent reactions of the resulting condensation products.

    Science.gov (United States)

    Gasparová, Renata; Lácová, Margita

    2005-01-01

    This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the gamma-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted. PMID:18007363

  9. PTFE treatment by remote atmospheric Ar/O2 plasmas: a simple reaction scheme model proposal

    CERN Document Server

    Carbone, E A D; Keuning, W; van der Mullen, J J A M

    2013-01-01

    Polytetrafluoroethylene (PTFE) samples were treated by a remote atmospheric pressure microwave plasma torch and analyzed by water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS). In the case of pure argon plasma a decrease of WCA is observed meanwhile an increase of hydrophobicity was observed when some oxygen was added to the discharge. The WCA results are correlated to XPS of reference samples and the change of WCA are attributed to changes in roughness of the samples. A simple kinetics scheme for the chemistry on the PTFE surface is proposed to explain the results.

  10. The effect of nuclear structure in the emission of reaction products in heavy-ion reactions

    Indian Academy of Sciences (India)

    Samir Kundu

    2014-04-01

    Study of intermediate mass fragments (IMFs) and light charged particles (LCPs) emission has been carried out for a few reactions involving -cluster and non--cluster systems to see how the emission processes are affected by nuclear clustering. Li, Be, B and -particles have been studied from α-clustered system 16O + 12C for 117, 125, 145 and 160 MeV bombarding energies respectively. The enhanced yields of near-entrance channel fragment B and large quadrupole deformation of the produced composite 28Si* extracted from LCP spectra indicate the survival of orbiting-like process in 16O + 12C system at these energies. The same IMFs emitted from the -cluster system 12C (77 MeV) + 28Si and nearby non- cluster 11B (64 MeV) + 28Si and 12C (73 MeV) + 27Al (all having the same excitation energy of ∼67 MeV) have also been studied. The fully energy damped (fusion–fission) and the partially energy damped (deep inelastic) components of the fragment energy spectra have been extracted. It has been found that the yields of the fully energy damped fragments for all the above reactions are in conformity with the respective statistical model predictions. The time-scales of various deep inelastic fragment emissions have been extracted from the angular distribution data. The angular momentum dissipation in deep inelastic collisions has been estimated from the data and it has been found to be close to the corresponding sticking limit value.

  11. Formic acid production from carbohydrates biomass by hydrothermal reaction

    International Nuclear Information System (INIS)

    The formation of formic acid or formate salts by hydrothermal oxidation of model biomass materials (glucose, starch and cellulose) was investigated. All experiments were conducted in a batch reactor, made of SUS 316 tubing, providing an internal volume of 5.7 cm3. A 30 wt% hydrogen peroxide aqueous solution was used as an oxidant. The experiments were carried out with temperature of 2500C, reaction time varying from 0.5 min to 5 min, H2O2 supply of 240%, and alkaline concentration varying from 0 to 1.25 M. Similar to glucose, in the cases of the oxidation of hydrothermal starch and cellulose, the addition of alkaline can also improve the yield of formic acid. And the yield were glucose>starch> cellulose in cases of with or without of alkaline addition.

  12. Miscible viscous fingering involving production of gel by chemical reactions

    Science.gov (United States)

    Nagatsu, Yuichiro; Hoshino, Kenichi

    2015-11-01

    We have experimentally investigated miscible viscous fingering with chemical reactions producing gel. Here, two systems were employed. In one system, sodium polyacrylate (SPA) solution and aluminum ion (Al3 +) solution were used as the more and less viscous liquids, respectively. In another system, SPA solution and ferric ion (Fe3 +) solution were used as the more and less viscous liquids, respectively. In the case of Al3 +, displacement efficiency was smaller than that in the non-reactive case, whereas in the case of Fe3 +, the displacement efficiency was larger. We consider that the difference in change of the patterns in the two systems will be caused by the difference in the properties of the gels. Therefore, we have measured the rheological properties of the gels by means of a rheometer. We discuss relationship between the VF patterns and the rheological measurement.

  13. Quasielastic production of polarized hyperons in antineutrino--nucleon reactions

    CERN Document Server

    Akbar, F; Athar, M Sajjad; Singh, S K

    2016-01-01

    We have studied the longitudinal and perpendicular polarizations of final hyperon($\\Lambda$,$\\Sigma$) produced in the antineutrino induced quasielastic charged current reactions on nucleon targets. The nucleon-hyperon transition form factors are determined from the experimental data on quasielastic $(\\Delta S =0)$ charged current (anti)neutrino--nucleon scattering and the semileptonic decay of neutron and hyperons assuming G--invariance, T--invariance and SU(3) symmetry. The vector transition form factors are obtained in terms of nucleon electromagnetic form factors for which various parameterizations available in literature have been used. A dipole parameterization for the axial vector form factor and the pseudoscalar transition form factor derived in terms of axial vector form factor assuming PCAC and GT relation extended to strangeness sector have been used in numerical evaluations. The flux averaged cross section and polarization observables corresponding to CERN Gargamelle experiment have been calculated...

  14. Mapping Students' Conceptual Modes When Thinking about Chemical Reactions Used to Make a Desired Product

    Science.gov (United States)

    Weinrich, M. L.; Talanquer, V.

    2015-01-01

    The central goal of this qualitative research study was to uncover major implicit assumptions that students with different levels of training in the discipline apply when thinking and making decisions about chemical reactions used to make a desired product. In particular, we elicited different ways of conceptualizing why chemical reactions happen…

  15. One-pot multi-reaction processes: synthesis of natural products and drug-like scaffolds

    OpenAIRE

    Calder, Ewen D D; Grafton, Mark W.; Sutherland, Andrew

    2014-01-01

    One-pot multi-reaction processes involving Overman rearrangements, metathesis cyclizations, and Diels–Alder reactions have been developed for the rapid and efficient synthesis of amino-substituted carbocyclic and heterocyclic compounds. This account describes the development and optimization of these processes, as well as their applications in the synthesis of natural products and drug-like scaffolds.

  16. Direct photon production in heavy-ion reactions at SPS and RHIC

    Indian Academy of Sciences (India)

    T Peitzmann

    2003-04-01

    A review on experimental results for direct photon production in heavy ion reactions is given. A brief survey of early direct photon limits from SPS experiments is presented. The first measurement of direct photons in heavy ion reactions from the WA98 collaboration is discussed and compared to theoretical calculations. An outlook on the perspective of photon measurements at RHIC is given.

  17. Advanced Maillard reaction end products are associated with Alzheimer disease pathology

    OpenAIRE

    Smith, M. A.; Taneda, S; Richey, P. L.; Miyata, S.; Yan, S D; Stern, D; Sayre, L. M.; Monnier, V M; Perry, G.

    1995-01-01

    During aging long-lived proteins accumulate specific post-translational modifications. One family of modifications, termed Maillard reaction products, are initiated by the condensation between amino groups of proteins and reducing sugars. Protein modification by the Maillard reaction is associated with crosslink formation, decreased protein solubility, and increased protease resistance. Here, we present evidence that the characteristic pathological structures associated with Alzheimer disease...

  18. Recent applications of intramolecular Diels-Alder reactions to natural product synthesis

    DEFF Research Database (Denmark)

    Juhl, M.; Tanner, David Ackland

    2009-01-01

    This tutorial review presents some recent examples of intramolecular Diels-Alder (IMDA) reactions as key complexity-generating steps in the total synthesis of structurally intricate natural products. The opportunities afforded by transannular (TADA) versions of the IMDA reaction in complex molecule...

  19. The effects of reactants ratios, reaction temperatures and times on Maillard reaction products of the L-ascorbic acid/L-glutamic acid system

    OpenAIRE

    Yong-Yan ZHOU; Li, Ya; Ai-Nong YU

    2016-01-01

    Abstract The transformation law of the Maillard reaction products with three different reactants ratios - equimolar reactants, excess L-glutamic acid and excess L-ascorbic acid reaction respectively, five different temperatures, and different time conditions for the L-ascorbic acid / L-glutamic acid system were investigated. Results showed that, the increase of the reaction time and temperature led to the increase of the browning products, uncoloured intermediate products, as well as aroma co...

  20. Multistrange baryon production in heavy ion reactions at the SPS

    CERN Document Server

    Antinori, Federico; Bloodworth, Ian J; Caliandro, R; Carrer, N; Di Bari, D; Di Liberto, S; Elia, D; Evans, D; Fanebust, K; Fayazzadeh, F; Fini, R A; Ftácnik, J; Ghidini, B; Grella, G; Gulino, M; Helstrup, H; Henriquez, M; Holme, A K; Huss, D; Jacholkowski, A; Jones, G T; Kinson, J B; Knudson, K; Králik, I; Lenti, V; Lietava, R; Loconsole, R A; Løvhøiden, G; Manzari, V; Mazzoni, M A; Meddi, F; Michalon, A; Michalon-Mentzer, M E; Morando, M; Norman, P I; Pastircák, B; Quercigh, Emanuele; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Segato, G F; Staroba, P; Thompson, M; Torrieri, G D; Urbán, J; Vik, T; Villalobos Baillie, O; Virgili, T; Votruba, M F; Závada, P

    2001-01-01

    Strange particle production in proton-beryllium, proton-lead and lead-lead interactions as measured by the WA97 experiment at the CERN SPS is presented. Strangeness enhancement is observed to increase with the strangeness content of the particle, reaching a factor 15 for Omega s. Inverse slope systematics are shown, including data from other experiments. (13 refs).

  1. Large fragment production calculations in relativistic heavy-ion reactions

    International Nuclear Information System (INIS)

    The abrasion-ablation model is briefly described and then used to calculate cross sections for production of large fragments resulting from target or projectile fragmentation in high-energy heavy-ion collisions. The number of nucleons removed from the colliding nuclei in the abrasion stage and the excitation energy of the remaining fragments (primary products) are calculated with the geometrical picture of two different models: the fireball and the firestreak models. The charge-to-mass dispersion of the primary products is calculated using either a model which assumes no correlations between proton and neutron positions inside the nucleus (hypergeometric distribution) or a model based upon the zero-point oscillations of the giant dipole resonance (NUC-GDR). Standard Weisskopf--Ewing statistical evaporation calculations are used to calculate final product distributions. Results of the pure abrasion-ablation model are compared with a variety of experimental data. The comparisons show the insufficiency of the extra-surface energy term used in the abrasion calculations. A frictional spectator interaction (FSI) is introduced which increases the average excitation energy of the primary products, and improves the results considerably in most cases. Agreements and discrepancies of the results calculated with the different theoretical assumptions and the experimental data are studied. Of particular relevance is the possibility of observing nuclear ground-state correlations.Results of the recently completed experiment of fragmentation of 213 Mev/A 40Ar projectiles are studied and shown not to be capable of answering that question unambiguously. But predictions for the upcoming 48Ca fragmentation experiment clearly show the possibility of observing correlation effects. 78 references

  2. Atmosphere

    Science.gov (United States)

    Ghosh, D.; Mitra, S. K.

    2014-05-01

    This paper investigates the high-temperature corrosion behavior of microstructurally different regions of the weldment of 9 Cr-1 Mo steel used in thermal power plant boiler in SO2 + O2 environment. The weldment is produced by tungsten inert gas welding method, and the different regions of the weldment (weld metal, heat-affected zone, and base metal) are exposed in SO2 + O2 (ratio 2:1) environment at 973 K for 120 h. The reaction kinetics and corrosion growth rate of different regions of weldment in isothermal condition are evaluated. The post corroded scales of the different specimens are studied in SEM, EDS, and XRD. The results indicate that the weld metal shows higher corrosion rate followed by HAZ and base metal. The higher rate of corrosion of weldmetal is mainly attributed to the least protective inner scale of Cr2O3 with minimum Cr Content. This is due to the formation of delta ferrite, which leads to the precipitation of the Cr-based secondary phases and depletes the free Cr from the matrix. The thermal cycles during welding at high temperature are favorable for the formation of delta ferrite. On the other hand, in absence of delta ferrite, the base metal and HAZ regions of the weldment show lower corrosion rate than weld metal. The difference in corrosion rate in the three regions of the weldment is supplemented by post-corroded scale characterizations.

  3. Impact of MODIS SWIR band calibration improvements on Level-3 atmospheric products

    Science.gov (United States)

    Wald, Andrew; Levy, Robert C.; Angal, Amit; Geng, Xu; Xiong, Jack; Hoffman, Kurt

    2016-05-01

    The spectral reflectance measured by the MODIS reflective solar bands (RSB) is used for retrieving many atmospheric science products. The accuracy of these products depends on the accuracy of the calibration of the RSB. To this end, the RSB of the MODIS instruments are primarily calibrated on-orbit using regular solar diffuser (SD) observations. For λ vapor, cloud fraction and cloud optical depth. The SD degradation correction in Terra bands 5 and 26 impact the spectral radiance and therefore the retrieval of these atmosphere products. Here, we describe the corrections to Bands 5 (1.24 μm) and 26 (1.38 μm), and produce three sets (B5, B26 correction = on/on, on/off, and off/off) of Terra-MODIS Level 1B (calibrated radiance product) data. By comparing products derived from these corrected and uncorrected Terra MODIS Level 1B (L1B) calibrations, dozens of L3 atmosphere products are surveyed for changes caused by the corrections, and representative results are presented. Aerosol and water vapor products show only small local changes, while some cloud products can change locally by >10%, which is a large change.

  4. Low temperature rate coefficients for the reactions of 1CH2 with reactive and non-reactive species, and the implications for Titan's atmosphere

    Science.gov (United States)

    Douglas, Kevin; Slater, Eloise; Blitz, Mark; Plane, John; Heard, Dwayne; Seakins, Paul

    2016-04-01

    The Cassini-Huygens mission to Titan revealed unexpectedly large amounts of benzene in the troposphere, and confirmed the absence of a global ethane ocean as predicted by photochemical models of methane conversion over the lifetime of the solar system. An important chemical intermediate in both the production and loss of benzene and ethane is the first electronically excited state of methylene, 1CH2. For example, at room temperature an important reaction of 1CH2 is with acetylene (R1a), leading to the formation of propargyl (C3H3)[1]. The subsequent recombination of propargyl radicals is the major suggested route to benzene in Titan's atmosphere (R2)[2]. In addition to reaction of 1CH2 leading to products, there is also competition between inelastic electronic relaxation to form the ground triplet state 3CH2 (R1b). This ground state 3CH2 has a markedly different reactivity to the singlet, reacting primarily with methyl radicals (CH3) to form ethene (R3). As methyl radical recombination is the primary route to ethane (R4)[3], reactions of 1CH2 will also heavily influence the ethane budget on Titan. 1CH2 + C2H2 → C3H3 + H (R1a) 1CH2 + C2H2 → 3CH2 + C2H2 (R1b) C3H3 + C3H3 → C6H6 (R2) 3CH2 + CH3 → C2H4 + H (R3) CH3 + CH3 (+ M) → C2H6 (R4) Thus this competition between chemical reaction and electronic relaxation in the reactions of 1CH2 with H2, CH4, C2H4, and C2H6 will play an important role in determining the benzene and ethane budgets on Titan. Despite this there are no measurements of any rate constants for 1CH2 at temperatures relevant to Titan's atmosphere (60 - 170 K). Using a pulsed Laval nozzle apparatus coupled with pulsed laser photolysis laser-induced fluorescence, the low temperature reaction kinetics for the removal of 1CH2 with nitrogen, hydrogen, methane, ethane, ethene, acetylene, and oxygen, have been studied. The results revealed an increase in the removal rate of 1CH2 at temperatures below 200 K, with a sharp increase of around a factor of

  5. Dynamical Coupled-Channel Model of Meson Production Reactions in the Nucleon Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    T.-S. H. Lee; A. Matsuyama; T. Sato

    2006-11-15

    A dynamical coupled-channel model is presented for investigating the nucleon resonances (N*) in the meson production reactions induced by pions and photons. Our objective is to extract the N* parameters and to investigate the meson production reaction mechanisms for mapping out the quark-gluon substructure of N* from the data. The model is based on an energy-independent Hamiltonian which is derived from a set of Lagrangians by using a unitary transformation method.

  6. OCCURING SOME BIOCHEMICAL REACTIONS IN FERMENTED MEAT PRODUCTS AND THEIR EFFECTS ON AROMA DEVELOPMENT

    OpenAIRE

    Gökalp, Hüsnü Yusuf; Hüdayi ERCOŞKUN; Ahmet Hilmi ÇON

    1998-01-01

    Glycolysis, lipolysis and proteolysis are the main biochemical reactions which effect characteristic flavour, aroma, color and texture development of fermented meat products. These reactions are results of the microorganisms or endogenous meat enzymes. The products which are results of glycolysis are firstly responsible from decreasing of pH. Volatile compounds from glycolysis effect aroma. Compounds formed by lipolysis are the main reason that effect aroma. 60 % volatile compounds formed...

  7. INFLUENCE OF REACTION TEMPERATURE AND REACTION TIME ON PRODUCT FROM HYDROTHERMAL TREATMENT OF BIOMASS RESIDUE

    OpenAIRE

    Jakaphong Kongpanya; Kanokorn Hussaro; Sombat Teekasap

    2014-01-01

    Thailand is facing with problems associated with biomass residue such as palm oil residues (oil palm trunks, oil palm fronds, empty fruit bunches, shells and fibers). Biomass is promising source for the production of an array of energy-related produts including, liquid, solid and gaseous fuels, heat, chemicals electricity and other materials. Therefore, the use of biomass for energy is not still fully utilization due to the high moisture content, lower heating value of the energy unit or low ...

  8. Interfacing Microbial Styrene Production with a Biocompatible Cyclopropanation Reaction**

    OpenAIRE

    Wallace, Stephen; Balskus, Emily P.

    2015-01-01

    Introducing new reactivity into living organisms is a major challenge in synthetic biology. Despite an increasing interest in both developing aqueous-compatible small molecule catalysts and engineering enzymes to perform new chemistry in vitro, the integration of non-native reactivity into metabolic pathways for small molecule production has been underexplored. Herein we report a biocompatible iron(III) phthalocyanine catalyst capable of efficient olefin cyclopropanation in the presence of a ...

  9. Aromatic products from reaction of lignin model compounds with UV-alkaline peroxide

    International Nuclear Information System (INIS)

    A series of guaiacyl and syringyl lignin model compounds and their methylated analogues were reacted with alkaline hydrogen peroxide while irradiating with UV light at 254 nm. The aromatic products obtained were investigated by gas chromatography-mass spectrometry (GC-MS). Guaiacol, syringol and veratrol gave no detectable aromatic products. However, syringol methyl ether gave small amounts of aromatic products, resulting from ring substitution and methoxyl displacement by hydroxyl radicals. Reaction of vanillin and syringaldehyde gave the Dakin reaction products, methoxy-1,4-hydroquinones, while reaction of their methyl ethers yielded benzoic acids. Acetoguaiacone, acetosyringone and their methyl ethers afforded several hydroxylated aromatic products, but no aromatic products were identified in the reaction mixtures from guaiacylpropane and syringylpropane. In contrast, veratrylpropane gave a mixture from which 17 aromatic hydroxylated compounds were identified. It is concluded that for phenolic lignin model compounds, particularly those possessing electrondonating aromatic ring substituents, ring-cleavage reactions involving superoxide radical anions are dominant, whereas for non-phenolic lignin models, hydroxylation reactions through attack of hydroxyl radicals prevail

  10. $X(3872)$ production from reactions involving $D$ and $D^*$ mesons

    CERN Document Server

    Torres, A Martinez; Navarra, F S; Nielsen, M; Abreu, Luciano M

    2014-01-01

    In this proceeding we show the results found for the cross sections of the processes $\\bar D D\\to\\pi X(3872)$, $\\bar D^* D\\to \\pi X(3872)$ and $\\bar D^* D^*\\to\\pi X(3872)$, information needed for calculations of the $X(3872)$ abundance in heavy ion collisions. Our formalism is based on the generation of $X(3872)$ from the interaction of the hadrons $\\bar D^0 D^{*0} - \\textrm{c.c}$, $D^- D^{*+} - \\textrm{c.c}$ and $D^-_s D^{*+}_s - \\textrm{c.c}$. The evaluation of the cross section associated with processes having $D^*$ meson(s) involves an anomalous vertex, $X\\bar D^* D^*$, which we have determined by considering triangular loops motivated by the molecular nature of $X(3872)$. We find that the contribution of this vertex is important. Encouraged by this finding we estimate the $X\\bar D^* D^*$ coupling, which turns out to be $1.95\\pm 0.22$. We then use it to obtain the cross section for the reaction $\\bar D^* D^*\\to\\pi X$ and find that the $X\\bar D^* D^*$ vertex is also relevant in this case. We also discuss t...

  11. The Mechanisms, Products, and Kinetics of Triclosan-Free Chlorine Reactions

    OpenAIRE

    Rule, Krista Lynn

    2004-01-01

    The kinetics, products, and reaction pathways of triclosan/free chlorine reactions were investigated for the pH range 3.5-11. Although pH dependent speciation occurs in both triclosan and free chlorine, only the reaction between HOCl and the phenolate-triclosan was found to play a significant role in the kinetics. The second order rate constant for the reaction between phenolate-triclosan and HOCl was found to be 5.40 (±1.82) à 103 M-1s-1. Three chlorinated triclosan intermediates were t...

  12. Characterization of reaction products of iron and iron salts and aqueous plant extracts

    International Nuclear Information System (INIS)

    The complexes formed in aqueous solution as a result of a reaction of iron and iron salts (Fe2+ and Fe3+) and some plant extracts were analyzed using Moessbauer spectroscopy and Fourier transform infrared. The extracts were obtained from Opuntia elatior mill., Acanthocereus pentagonus (L.) Britton, Mimosa tenuiflora, Caesalpinia coriaria (Jacq.) Willd., Bumbacopsis quinata (Jacq.) Dugand and Acacia mangium Willd., plants growing wildly in different zones of the Isthmus of Panama. Results suggest the formation of mono- and bis-type complexes, and in some cases, the occurrence of a redox reaction. The feasibility of application of the studied extracts as atmospheric corrosion inhibitors is discussed

  13. Characterization of reaction products of iron and iron salts and aqueous plant extracts

    Science.gov (United States)

    Jaén, J. A.; García de Saldaña, E.; Hernández, C.

    1999-11-01

    The complexes formed in aqueous solution as a result of a reaction of iron and iron salts (Fe2+ and Fe3+) and some plant extracts were analyzed using Mössbauer spectroscopy and Fourier transform infrared. The extracts were obtained from Opuntia elatior mill., Acanthocereus pentagonus (L.) Britton, Mimosa tenuiflora, Caesalpinia coriaria (Jacq.) Willd., Bumbacopsis quinata (Jacq.) Dugand and Acacia mangium Willd., plants growing wildly in different zones of the Isthmus of Panama. Results suggest the formation of mono- and bis-type complexes, and in some cases, the occurrence of a redox reaction. The feasibility of application of the studied extracts as atmospheric corrosion inhibitors is discussed.

  14. Characterization of reaction products of iron and iron salts and aqueous plant extracts

    Energy Technology Data Exchange (ETDEWEB)

    Jaen, J.A. [Universidad de Panama, Centro de Investigaciones con Tecnicas Nucleares/Depto. de Quimica (Panama); Garcia de Saldana, E.; Hernandez, C. [Universidad de Panama, Maestria en Ciencias Quimicas (Panama)

    1999-11-15

    The complexes formed in aqueous solution as a result of a reaction of iron and iron salts (Fe{sup 2+} and Fe{sup 3+}) and some plant extracts were analyzed using Moessbauer spectroscopy and Fourier transform infrared. The extracts were obtained from Opuntia elatior mill., Acanthocereus pentagonus (L.) Britton, Mimosa tenuiflora, Caesalpinia coriaria (Jacq.) Willd., Bumbacopsis quinata (Jacq.) Dugand and Acacia mangium Willd., plants growing wildly in different zones of the Isthmus of Panama. Results suggest the formation of mono- and bis-type complexes, and in some cases, the occurrence of a redox reaction. The feasibility of application of the studied extracts as atmospheric corrosion inhibitors is discussed.

  15. 40 CFR 721.9400 - Reaction product of phenolic pentaerythritol tetraesters with fatty acid esters and oils, and...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Reaction product of phenolic... Reaction product of phenolic pentaerythritol tetraesters with fatty acid esters and oils, and glyceride... substances identified generically as Reaction product of phenolic pentaerythritol tetraesters with fatty...

  16. Propagation and secondary production of low energy antiprotons in the atmosphere

    Science.gov (United States)

    Bowen, T.; Moats, A.

    1985-01-01

    Current theories, in which the observed antiproton component is attributed strictly to secondary production in high energy inelastic collisions of protons with the interstellar medium or the atmosphere, apparently fail to explain the relatively high p vertical intensities measured at mountain and balloon altitudes. Therefore, a more careful calculation of the theoretical secondary intensity spectra is required before more exotic sources for these excess p's can be explored. A one dimensional diffusion equation is used to calculate the expected vertical intensity of p's due only to secondary production in the atmosphere; any assumed primary p spectrum is also included. Two adjustable parameters, the inelasticity and charge exchange in nucleon-nucleus collisions, were included in the algorithm. In order to obtain an independent estimate of their values the proton vertical intensities in the atmosphere were calculated, adjusting the parameters until the curves fit the experimental proton data, and then assumed that these values were identical in antinucleon-nucleus collisions.

  17. The Phase Behavior Effect on the Reaction Engineering of Transesterification Reactions and Reactor Design for Continuous Biodiesel Production

    Science.gov (United States)

    Csernica, Stephen N.

    transitions from two phases to a single phase, or pseudo-single phase. The transition to a single phase or pseudo-single phase is a function of the methanol content. Regardless, the maximum observed reaction rate occurs at the point of the phase transition, when the concentration of triglycerides in the methanol phase is largest. The phase transition occurs due to the accumulation of the primary product, biodiesel methyl esters. Through various experiments, it was determined that the rate of the triglyceride mass transfer into the methanol phase, as well as the solubility of triglycerides in methanol, increases with increasing methyl ester concentration. Thus, there exists some critical methyl ester concentration which favors the formation of a single or pseudo-single phase system. The effect of the by-product glycerol on the reaction kinetics was also investigated. It was determined that at low methanol to triglyceride molar ratios, glycerol acts to inhibit the reaction rate and limit the overall triglyceride conversion. This occurs because glycerol accumulates in the methanol phase, i.e. the primary reaction volume. When glycerol is at relatively high concentrations within the methanol phase, triglycerides become excluded from the reaction volume. This greatly reduces the reaction rate and limits the overall conversion. As the concentration of methanol is increased, glycerol becomes diluted and the inhibitory effects become dampened. Assuming pseudo-homogeneous phase behavior, a simple kinetic model incorporating the inhibitory effects of glycerol was proposed based on batch reactor data. The kinetic model was primarily used to theoretically compare the performance of different types of continuous flow reactors for continuous biodiesel production. It was determined that the inhibitory effects of glycerol result in the requirement of very large reactor volumes when using continuous stirred tank reactors (CSTR). The reactor volume can be greatly reduced using tubular style

  18. Potential geographic distribution of atmospheric nitrogen deposition from intensive livestock production in North Carolina, USA

    Energy Technology Data Exchange (ETDEWEB)

    Costanza, Jennifer K. [Curriculum in Ecology, University of North Carolina at Chapel Hill, Campus Box 3275, Chapel Hill, NC 27599-3275 (United States)], E-mail: costanza@unc.edu; Marcinko, Sarah E. [Curriculum in Ecology, University of North Carolina at Chapel Hill, Campus Box 3275, Chapel Hill, NC 27599-3275 (United States); Goewert, Ann E. [Department of Geological Sciences, Campus Box 3315, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3315 (United States); Mitchell, Charles E. [Curriculum in Ecology, University of North Carolina at Chapel Hill, Campus Box 3275, Chapel Hill, NC 27599-3275 (United States)

    2008-07-15

    To examine the consequences of increased spatial aggregation of livestock production facilities, we estimated the annual production of nitrogen in livestock waste in North Carolina, USA, and analyzed the potential distribution of atmospheric nitrogen deposition from confined animal feeding operations ('CAFO') lagoons. North Carolina is a national center for industrial livestock production. Livestock is increasingly being raised in CAFOs, where waste is frequently held, essentially untreated, in open-air lagoons. Reduced nitrogen in lagoons is volatilized as ammonia (NH{sub 3}), transported atmospherically, and deposited to other ecosystems. The Albemarle-Pamlico Sound, NC, is representative of nitrogen-sensitive coastal waters, and is a major component of the second largest estuarine complex in the U.S. We used GIS to model the area of water in the Sound within deposition range of CAFOs. We also evaluated the number of lagoons within deposition range of each 1 km{sup 2} grid cell of the state. We considered multiple scenarios of atmospheric transport by varying distance and directionality. Modeled nitrogen deposition rates were particularly elevated for the Coastal Plain. This pattern matches empirical data, suggesting that observed regional patterns of reduced nitrogen deposition can be largely explained by two factors: limited atmospheric transport distance, and spatial aggregation of CAFOs. Under our medium-distance scenario, a small portion (roughly 22%) of livestock production facilities contributes disproportionately to atmospheric deposition of nitrogen to the Albemarle-Pamlico Sound. Furthermore, we estimated that between 14-37% of the state receives 50% of the state's atmospheric nitrogen deposition from CAFO lagoons. The estimated total emission from livestock is 134,000 t NH{sub 3} yr{sup -1}, 73% of which originates from the Coastal Plain. Stronger waste management and emission standards for CAFOs, particularly those on the Coastal Plain

  19. Limonene ozonolysis in the presence of nitric oxide: Gas-phase reaction products and yields

    Science.gov (United States)

    Ham, Jason E.; Harrison, Joel C.; Jackson, Stephen R.; Wells, J. R.

    2016-05-01

    The reaction products from limonene ozonolysis were investigated using the new carbonyl derivatization agent, O-tert-butylhydroxylamine hydrochloride (TBOX). With ozone (O3) as the limiting reagent, five carbonyl compounds were detected. The yields of the carbonyl compounds are discussed with and without the presence of a hydroxyl radical (OHrad) scavenger, giving insight into the influence secondary OH radicals have on limonene ozonolysis products. The observed reaction product yields for limonaketone (LimaKet), 7-hydroxyl-6-oxo-3-(prop-1-en-2-yl)heptanal (7H6O), and 2-acetyl-5-oxohexanal (2A5O) were unchanged suggesting OHrad generated by the limonene + O3 reaction does not contribute to their formation. The molar yields of 3-isopropenyl-6-oxo-heptanal (IPOH) and 3-acetyl-6-oxoheptanal (3A6O) decreased by 68% and >95%; respectively, when OHrad was removed. This suggests that OHrad radicals significantly impact the formation of these products. Nitric oxide (NO) did not significantly affect the molar yields of limonaketone or IPOH. However, NO (20 ppb) considerably decreased the molar reaction product yields of 7H6O (62%), 2A5O (63%), and 3A6O (47%), suggesting NO reacted with peroxyl intermediates, generated during limonene ozonolysis, to form other carbonyls (not detected) or organic nitrates. These studies give insight into the transformation of limonene and its reaction products that can lead to indoor exposures.

  20. Production of neutron-rich Ca isotopes in transfer-type reactions

    International Nuclear Information System (INIS)

    Possibilities of production of neutron-rich isotopes 56,58,60Ca in transfer-type reactions are analyzed. The optimal conditions for their production are suggested. The neutron separation energies in nuclei near the neutron drip line can be estimated by measuring the excitation functions

  1. Production of 100Sn in fusion reactions via cluster emission channels

    Directory of Open Access Journals (Sweden)

    Kalandarov Sh. A.

    2015-01-01

    Full Text Available The possibilities of production of the doubly magic nucleus 100Sn in complete fusion and quasifission reactions with stable and radioactive ion beams are investigated within a dinuclear system model. The excitation functions for production of the exotic nuclei 100−103Sn via cluster emission channels are predicted for future experiments.

  2. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    Science.gov (United States)

    2010-07-01

    ... product with maleic anhydride. 721.524 Section 721.524 Protection of Environment ENVIRONMENTAL PROTECTION... with maleic anhydride. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  3. Maillard reaction products of rice protein hydrolysates with mono-, oligo- and polysaccharides

    Science.gov (United States)

    Rice protein, a byproduct of rice syrup production, is abundant but, its lack of functionality prevents its wide use as a food ingredient. Maillard reaction products of (MRPs) hydrolysates from the limited hydrolysis of rice protein (LHRP) and various mono-, oligo- and polysaccharides were evaluat...

  4. An Upstream By-product from Ester Activation via NHC-Catalysis Catalyzes Downstream Sulfonyl Migration Reaction.

    Science.gov (United States)

    Han, Runfeng; He, Liwenze; Liu, Lin; Xie, Xingang; She, Xuegong

    2016-01-01

    A sequential reaction combining N-heterocyclic carbene (NHC) and N-hydroxyphthalimide (NHPI) catalysis allowed for the upstream by-product NHPI, which was generated in the NHC-catalyzed cycloaddition reaction, to act as the catalyst for a downstream nitrogen-to-carbon sulfonyl migration reaction. Enantiomeric excess of the major product in the cycloaddition reaction remained intact in the follow-up sulfonyl migration reaction. PMID:26522328

  5. Development of Tools for the pre- and post-Launch Evaluation of VIIRS Atmospheric Products

    Science.gov (United States)

    Cureton, G. P.

    2011-12-01

    To facilitate the completion of the product evaluation tasks assigned to the Atmosphere PEATE and associated NPP Science Team, various software tools have been developed. Such tools are intended to provide an accessible path towards visualization of VIIRS swath data (radiometric and atmospheric products), the generation and visualization of globally gridded VIIRS datasets for use in daily and monthly averages, and the analysis of multi-sensor co-located data for cross-validation. In addition to end-user tools, there is also effort made to provide easy-to-use NPP sensor specific software libraries to enable NPP science team members to develop their own tools, without having to learn the minutiae of the NPP data formats. The NPOESS Preparatory Project (NPP) mission will provide a first look at a new generation of science products from U.S. operational polar orbiting Earth observing satellites. The primary focus will be on the production of Sensor Data Record (SDR) and Environmental Data Record (EDR) science products in the Interface Data Processing Segment (IDPS) of the Joint Polar Satellite System (JPSS) Ground System. The NASA NPP Science Teams have been tasked with evaluation of the anticipated operational products from the IDPS within a facility known as the Science Data Segment (SDS). Within the SDS, NASA has established five Product Evaluation and Algorithm Test Elements (PEATEs). The purpose of each PEATE is to enable its associated NPP Science Team to evaluate the operational SDRs and EDRs (both pre-launch and post-launch) from NPP efficiently. The PEATEs are organized into categories including Atmosphere, Land, Ocean, Ozone and Sounder. The Atmosphere PEATE has been established within the Space Science and Engineering Center (SSEC) at the University of Wisconsin-Madison.

  6. Aura Atmospheric Data Products and Their Availability from NASA Goddard Earth Sciences DAAC

    Science.gov (United States)

    Ahmad, S.; Johnson, J.; Gopalan, A.; Smith, P.; Leptoukh, G.; Kempler, S.

    2004-01-01

    NASA's EOS-Aura spacecraft was launched successfully on July 15, 2004. The four instruments onboard the spacecraft are the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Tropospheric Emission Spectrometer (TES), and the High Resolution Dynamics Limb Sounder (HBDLS). The Aura instruments are designed to gather earth sciences measurements across the ultraviolet, visible, infra-red, thermal and microwave regions of the electromagnetic spectrum. Aura will provide over 70 distinct standard atmospheric data products for use in ozone layer and surface UV-B monitoring, air quality forecast, and atmospheric chemistry and climate change studies (http://eosaura.gsfc.nasa.gov/). These products include earth-atmosphere radiances and solar spectral irradiances; total column, tropospheric, and profiles of ozone and other trace gases, surface W-B flux; clouds and aerosol characteristics; and temperature, geopotential height, and water vapor profiles. The MLS, OMI, and HIRDLS data products will be archived at the NASA Goddard Earth Sciences (GES) Distributed Active Archive Center (DAAC), while data from TES will be archived at NASA Langley Research Center DAAC. Some of the standard products which have gone through quick preliminary checks are already archived at the GES DAAC (http://daac.nsfc.nasa.gov/) and are available to the Aura science team and data validation team members for data validation; and to the application and visualization software developers, for testing their application modules. Once data are corrected for obvious calibration problems and partially validated using in-situ observations, they would be made available to the broader user community. This presentation will provide details of the whole suite of Aura atmospheric data products, and the time line of the availability of the rest of the preliminary products and of the partially validated provisional products. Software and took available for data access, visualization, and data

  7. Hydration reactions and ettringite formation in selected cementitious coal conversion by-products

    International Nuclear Information System (INIS)

    Cementitious reactions and ettringite formation, which occur when water is added to high-calcium fly ash, to many dry flue gas desulfurization solids, and to two of the residues from the emerging clean coal technologies, fluidized bed combustion and limestone injection multiphase burner, have been studied. The parameters varied included water to solid ratio and curing time. Crystalline reactants and products were monitored by X-ray powder diffraction. The amount of ettringite, the principal crystalline cementitious reaction product, was determined after three months of curing. In this paper results are discussed in terms of available Ca, Al and S in each by-product and w/s ratio

  8. Atmospheric reactivity of hydroxyl radicals with guaiacol (2-methoxyphenol), a biomass burning emitted compound: Secondary organic aerosol formation and gas-phase oxidation products

    Science.gov (United States)

    Lauraguais, Amélie; Coeur-Tourneur, Cécile; Cassez, Andy; Deboudt, Karine; Fourmentin, Marc; Choël, Marie

    2014-04-01

    Methoxyphenols are low molecular weight semi-volatile polar aromatic compounds produced from the pyrolysis of wood lignin. The reaction of guaiacol (2-methoxyphenol) with hydroxyl radicals has been studied in the LPCA simulation chamber at (294 ± 2) K, atmospheric pressure, low relative humidity (RH Flame Ionization Detection) and GC-MS (Gas Chromatography - Mass Spectrometry) analysis show the formation of nitroguaiacol isomers as main oxidation products in the gas- and aerosol-phases. In the gas-phase, the formation yields were (10 ± 2) % for 4-nitroguaiacol (1-hydroxy-2-methoxy-4-nitrobenzene; 4-NG) and (6 ± 2) % for 3- or 6-nitroguaiacol (1-hydroxy-2-methoxy-3-nitrobenzene or 1-hydroxy-2-methoxy-6-nitrobenzene; 3/6-NG; the standards are not commercially available so both isomers cannot be distinguished) whereas in SOA their yield were much lower (≤0.1%). To our knowledge, this work represents the first identification of nitroguaiacols as gaseous oxidation products of the OH reaction with guaiacol. As the reactivity of nitroguaiacols with atmospheric oxidants is probably low, we suggest using them as biomass burning emission gas tracers. The atmospheric implications of the guaiacol + OH reaction are also discussed.

  9. Systematic Study of Technetium Production by Proton-Induced Reactions on Molybdenum

    Science.gov (United States)

    Lamere, Edward; Gilardy, Gwenaelle; Meisel, Zach; Moran, Michael; Skulski, Michael; Couder, Manoel

    2015-10-01

    Recent shortages in the world-wide supply of 99mTc have sparked interest in developing alternative production methods which do not rely on fission based 99Mo. The direct production of 99mTc from proton induced reactions on enriched 100Mo targets is one such approach. With this approach, 99mTc must be chemically extracted from the irradiated target and therefore radiopharmaceuticals will contain a mixture of all Tc-species produced from the proton bombardment. Commercial viability of cyclotron-produced 99mTc will depend on a number of factors including, production yield, radiochemical purity, and specific activity. Reactions on trace impurities in the targets has been shown to impact these factors dramatically. Precise cross-section measurements for not just the main reaction, 99mTc(p,2n), but for all Mo + p reactions that lead to Tc or Mo species are required for proper assessment of this 99mTc production technique. We will introduce a systematic study of proton-induced reactions on 92, 94-98, 100 Mo currently being performed at the University of Notre Dame. First results of 96Mo + p reactions will be presented. NRC-HQ-12-G-38-0073.

  10. Behaviour of 222Rn and its daughter products in open atmosphere

    International Nuclear Information System (INIS)

    In this contribution the influence of the meteorological conditions on activity concentrations of the outdoor 222Rn and its daughter products is discussed in detail. In addition, the correlation between concentrations of measured radionuclides is studied and empirical relations for concentrations of radon daughter products are presented. he courses of the activity concentrations of 222Rn and its short-lived decay products in the outdoor atmosphere are very similar even in some details. The average equilibrium factor F determined on the basis of our measurements in the outdoor atmosphere is approximately about 20 % lower than the value F recommended by UNSCEAR 1996 for the open air (F = 0,7). The obtained nonlinear relations between radon and its decay products reduce the applications of decay products in the atmospheric studies on one hand but on the other hand they can be useful at the calculation of the equilibrium equivalent radon concentration with the aim to determine the effective radon dose on the basis of the measurements of its activity concentrations only. (authors)

  11. Investigation of terpinolene + ozone or terpinolene + nitrate radical reaction products using denuder/filter apparatus

    Science.gov (United States)

    Harrison, Joel C.; Wells, J. R.

    2013-12-01

    Terpinolene's (1-methyl-4-(propan-2-ylidene)cyclohexene) reaction with ozone or the nitrate radical was investigated using a denuder/filter apparatus in order to characterize gas-phase and particulate reaction products. Identification of the reaction products (i.e., aldehydes, ketones, dicarbonyls and carboxylic acids) was made using two derivatization methods; O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) to derivatize the carbonyl products or 3-Ethyl-1-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC) and 2,2,2-trifluoroethylamine hydrochloride (TFEA) to derivatize the carboxylic acid products. Proposed carbonyl products for ozonolysis of terpinolene are: 4-methylcyclohex-3-en-1-one, 2-hydroxy-4-methylcyclohex-3-en-1-one, glyoxal, methyl glyoxal, 3-oxobutanal, and 6-oxo-3-(propan-2-ylidene)heptanal. Proposed carbonyl products for nitrate radical reaction of terpinolene are: 2-hydroxy-4-methylcyclohex-3-en-1-one, glyoxal, methyl glyoxal, and 4-oxopentanal. No carboxylic acid products were detected with either oxidizing reactant.

  12. Production and study of new neutron rich heavy nuclei in multinucleon transfer reactions

    International Nuclear Information System (INIS)

    Problems of production and study of new neutron-enriched heavy nuclei are discussed. Low-energy multinucleon transfer reactions are shown to be quite appropriate for this purpose. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N = 126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei look very promising for planning such experiments at currently available accelerators. These experiments, however, are rather expensive and difficult to perform because of low intensities of the massive projectile beams and problems of separating and detecting the heavy reaction products. Thus, realistic predictions of the corresponding cross sections for different projectile-target combinations are definitely required. Some uncertainty still remains in the values of several parameters used for describing the low-energy nuclear dynamics. This uncertainty does not allow one to perform very accurate predictions for the productions of new heavier-than-target (trans-target) nuclei in multinucleon transfer reactions. Nevertheless these predictions are rather promising (large cross sections) to start such experiments at available accelerators if the problem of separation of heavy transfer reaction products would be solved. (authors)

  13. Effect of synthesis atmosphere on photocatalytic hydrogen production of NaNbO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Nana [Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Institute of Physics for Microsystems, Henan University, Kaifeng 475004 (China); Li, Guoqiang, E-mail: gqli1980@gmail.com [Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Institute of Physics for Microsystems, Henan University, Kaifeng 475004 (China); Zhang, Weifeng, E-mail: wfzhang@henu.edu.cn [Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Institute of Physics for Microsystems, Henan University, Kaifeng 475004 (China)

    2014-08-15

    The NaNbO{sub 3} photocatalysts were prepared under air, H{sub 2}/Ar and O{sub 2} atmosphere by a solid state reaction. These samples were characterized by X-ray diffraction, UV–vis spectroscopy, Raman spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The photocatalytic activity of NaNbO{sub 3} samples were evaluated from the hydrogen evolution from an aqueous methanol solution. The hydrogen evolution rate of NaNbO{sub 3} under air, H{sub 2}/Ar and O{sub 2} atmosphere showed an increasing trend in turn. Moreover, the hydrogen evolution rate exhibited a linear increase with the surface oxygen defects.

  14. Effects of Controlled Atmospheres on Production of Sesquiterpenoid Stress Metabolites by White Potato Tuber

    Science.gov (United States)

    Alves, Leo M.; Heisler, Edward G.; Kissinger, John C.; Patterson, Joseph M.; Kalan, Edwin B.

    1979-01-01

    Levels of katahdinone (solavetivone), lubimin, rishitin, and phytuberin, sesquiterpenoid stress metabolites of white potato (Solanum tuberosum), were monitored in tuber slices which were challenged with an extract of Phytophthora infestans and incubated under controlled atmospheres. A mixture of ethylene in air enhanced stress metabolite production. This enhancement was amplified by higher partial pressures of oxygen. Stress metabolite production was inhibited by salicylhydroxamic acid. These results suggest the involvement of cyanide-resistant respiration in the production of potato stress metabolites, compounds which may serve as phytoalexins. PMID:16660728

  15. Corrosion Products and Formation Mechanism During Initial Stage of Atmospheric Corrosion of Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    XIAO Kui; DONG Chao-fang; LI Xiao-gang; WANG Fu-ming

    2008-01-01

    The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM)and Raman spectroscopy.The results showed that two different shapes of corrosion products,that is,ring and chain,were formed in the initial stage of corrosion.MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites.The ring-shaped products were composed of lepidocrocite (γ-FeOOH) and maghemite(γ-Fe2 O3) transformed from lepidocrocite.The chain-type products were goethite (α-FeOOH).A formation mechanism of the corrosion products is proposed.

  16. Hydrogen production from banyan leaves using an atmospheric-pressure microwave plasma reactor.

    Science.gov (United States)

    Lin, Yuan-Chung; Wu, Tzi-Yi; Jhang, Syu-Ruei; Yang, Po-Ming; Hsiao, Yi-Hsing

    2014-06-01

    Growth of the hydrogen market has motivated increased study of hydrogen production. Understanding how biomass is converted to hydrogen gas can help in evaluating opportunities for reducing the environmental impact of petroleum-based fuels. The microwave power used in the reaction is found to be proportional to the rate of production of hydrogen gas, mass of hydrogen gas produced per gram of banyan leaves consumed, and amount of hydrogen gas formed with respect to the H-atom content of banyan leaves decomposed. Increase the microwave power levels results in an increase of H2 and decrease of CO2 concentrations in the gaseous products. This finding may possibly be ascribed to the water-gas shift reaction. These results will help to expand our knowledge concerning banyan leaves and hydrogen yield on the basis of microwave-assisted pyrolysis, which will improve the design of hydrogen production technologies. PMID:24721492

  17. Multimass thermal desorption spectroscopy as a monitoring device for chemical reaction products

    OpenAIRE

    Zagatta, Gunther; Müller, H; Böwering, N.; Heinzmann, Ulrich

    1994-01-01

    To observe the products of surface reaction mechanisms we combined a standard quadrupole mass spectrometer featuring high-speed scanning options with fast data acquisition and a computer-controlled sample heating system. This combination served to obtain a general view (like a 'fingerprint') of the reaction occurring on a Pt(100) crystal upon heating the adsorbate covered surface, as well as to allow for a detailed analysis of the gas compounds leaving the surface within a single measurement....

  18. Reactions of the CN Radical with Benzene and Toluene: Product Detection and Low-Temperature Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Trevitt, Adam J.; Goulay, Fabien; Taatjes, Craig A.; Osborn, David L.; Leone, Stephen R.

    2009-12-23

    Low temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165 and 295 K is found to be relatively constant over this temperature range, 3.9 - 4.9 x 10-10 cm3 molecule-1 s-1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a slower rate coefficient of 1.3 x 10-10 cm3 molecule-1 s-1 at 105 K. At room temperature, non-exponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C6H5CN) is the only product recorded with no detectable evidence for a C6H5 + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC6H4CH3) constitutes the only detected product. It is not possible to differentiate among the ortho, meta and para isomers of cyanotoluene because of their similar ionization energies and the ~;; 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C6H5CH2) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn?s moon Titan (~;;100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K).

  19. Mechanism of anti-influenza virus activity of Maillard reaction products derived from Isatidis roots

    OpenAIRE

    Ke, Lijing

    2011-01-01

    The cyto-protective compositions and effects of antiviral Maillard reaction products (MRPs) derived from roots of Isatis indigotica F. were examined using biochemical and biophysical methods. The Maillard reaction was identified as the main source of compounds with antiviral activity, an observation which has led to the proposal of a new class of active compounds that protect cells from influenza virus infection. In the roots, arginine and glucose were revealed to be the predom...

  20. Hypernuclear production in the (K/sup -/, pi /sup -/) reaction Heidelberg-Saclay-Strasbourg collaboration

    CERN Document Server

    Bertini, R; Birien, P; Braune, K; Brückner, W; Catz, H; Chaumeaux, A; Faessler, M A; Frey, R W; Garreta, D; Ketel, T; Kilian, K; Mayer, B; Niewisch, J; Pietrzyk, B; Povh, B; Ritter, H G; Uhrmacher, M

    1981-01-01

    Cross sections for the production of hypernuclei were measured in the reaction A(K/sup -/, pi /sup -/)/sub Lambda /A on light and heavy nuclear targets, using a separated K/sup -/ beam at the CERN Proton Synchrotron. The pions were detected in the forward direction. The results are compared with cross sections calculated under the assumption that the reaction took place on a single neutron. The good agreement between the measured and the calculated cross sections justifies the use of the (K/sup -/, pi /sup -/) reaction in order to obtain spectroscopic information on hypernuclei. (21 refs).

  1. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    Science.gov (United States)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  2. Neutron Production Using Alpha-Be Reaction on the Neutron Generator Accelerator

    International Nuclear Information System (INIS)

    In order to obtain data for development of small scale Accelerator Driven System (ADS), calculations of neutron production that use alpha-Be reaction on the acceleration energy range of 100 to 500 keV have been carried out. The result of neutron yield calculation was compared with calculation result of D-T reaction and both calculations were treated for thick target. At the energy of 100 keV; alpha-Be reaction produces neutron yield about 1/10 compared to that of D-T reaction and increases to 1/5 at energy of 500 keV. At the same acceleration voltage of 250 kV, where the alpha energy is 500 keV and deuteron energy is 250 keV; the neutron yield of alpha-Be reaction is 1/3 of that in D-T reaction. On the last mentioned condition and considering that target cost of Be is cheaper than the cost of T, neutron production on a neutron generator accelerator that uses alpha-Be reaction is a competitive method as neutron source, especially for ADS. (author)

  3. Mutagenicity screening of reaction products from the enzyme-catalyzed oxidation of phenolic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Massey, I.J.; Aitken, M.D.; Ball, L.M.; Heck, P.E. (Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Environmental Sciences and Engineering)

    1994-11-01

    Phenol-oxidizing enzymes such as peroxidases, laccases, and mushroom polyphenol oxidase are capable of catalyzing the oxidation of a wide range of phenolic pollutants. Although the use of these enzymes in waste-treatment applications has been proposed by a number of investigators, little information exists on the toxicological characteristics of the oxidation products. The enzymes chloroperoxidase, horseradish peroxidase, lignin peroxidase, and mushroom polyphenol oxidase were used in this study to catalyze the oxidation of phenol, several mono-substituted phenols, and pentachlorophenol. Seventeen reaction mixtures representing selected combinations of enzyme and parent phenol were subjected to mutagenicity screening using the Ames Salmonella typhimurium plate incorporation assay; five selected mixtures were also incubated with the S9 microsomal preparation to detect the possible presence of promutagens. The majority of reaction mixtures tested were not directly mutagenic, and none of those tested with S9 gave a positive response. Such lack of mutagenicity of enzymatic oxidation products provides encouragement for establishing the feasibility of enzyme-catalyzed oxidation as a waste-treatment process. The only positive responses were obtained with reaction products from the lignin peroxidase-catalyzed oxidation of 2-nitrophenol and 4-nitrophenol. Clear positive responses were observed when strain TA100 was incubated with 2-nitrophenol reaction-product mixtures, and when strain TA98 was incubated with the 4-nitrophenol reaction mixture. Additionally, 2,4-dinitrophenol was identified as a reaction product from 4-nitrophenol, and preliminary evidence indicates that both 2,4- and 2,6-dinitrophenol are produced from the oxidation of 2-nitrophenol. Possible mechanism by which these nitration reactions occur are discussed.

  4. Assessing long-term impacts of increased crop productivity on atmospheric CO2.

    Science.gov (United States)

    Cavazzoni, J; Volk, T

    1996-05-01

    A full assessment of the impacts of land clearance and crop production on atmospheric CO2 requires a systems approach. By considering long-term soil carbon changes and fossil fuel energy inputs, we show that increased crop productivity will alleviate CO2 release to the atmosphere primarily by preventing additional land cultivation. Each hectare of cropland undergoing a simulated threefold crop productivity increase here prevents a net release on the order of 150-200 Mg C to the atmosphere over 100 years by avoiding additional land cultivation which would otherwise be required. This effective carbon sink would slowly diminish with time due to fossil fuel energy input requirements. However, future self-containment of the energy needs of high-yield crop production may displace on the order of 1.0 Pg C per year of fossil fuel carbon, in addition to the carbon sink attributable to avoided land cultivation. By avoiding land cultivation, high yield crop systems also preserve natural ecosystems. PMID:11539330

  5. NASA Langley Atmospheric Science Data Centers Near Real-Time Data Products

    Science.gov (United States)

    Davenport, T.; Parker, L.; Rinsland, P. L.

    2014-12-01

    Over the past decade the Atmospheric Science Data Center (ASDC) at NASA Langley Research Center has archived and distributed a variety of satellite mission data sets. NASA's goal in Earth science is to observe, understand, and model the Earth system to discover how it is changing, to better predict change, and to understand the consequences for life on Earth. The ASDC has collaborated with Science Teams to accommodate emerging science users in the climate and modeling communities. The ASDC has expanded its original role to support operational usage by related Earth Science satellites, support land and ocean assimilations, support of field campaigns, outreach programs, and application projects for agriculture and energy industries to bridge the gap between Earth science research results and the adoption of data and prediction capabilities for reliable and sustained use in Decision Support Systems (DSS). For example; these products are being used by the community performing data assimilations to regulate aerosol mass in global transport models to improve model response and forecast accuracy, to assess the performance of components of a global coupled atmospheric-ocean climate model, improve atmospheric motion vector (winds) impact on numerical weather prediction models, and to provide internet-based access to parameters specifically tailored to assist in the design of solar and wind powered renewable energy systems. These more focused applications often require Near Real-Time (NRT) products. Generating NRT products pose their own unique set challenges for the ASDC and the Science Teams. Examples of ASDC NRT products and challenges will be discussed.

  6. Product inhibition of enzymatic hydrolysis of cellulose: are we running the reactions all wrong?

    DEFF Research Database (Denmark)

    Meyer, Anne S.

    2012-01-01

    Enzyme catalyzed deconstruction of cellulose to glucose is an important technology step in lignocellulose-to-ethanol processing as well as in the future biorefinery based production of novel products to replace fossil oil based chemistry. The main goals of the enzymatic biomass saccharification i....... Based on cellulose inhibition kinetics the talk will illustrate the suitability of membrane reactor technology for improving cellulose substrate conversion efficiency.......Enzyme catalyzed deconstruction of cellulose to glucose is an important technology step in lignocellulose-to-ethanol processing as well as in the future biorefinery based production of novel products to replace fossil oil based chemistry. The main goals of the enzymatic biomass saccharification...... include high substrate conversion (maximal yields), maximal enzyme efficiency, maximal volumetric reactor productivity, minimal equipment investment, minimal size, and short reaction time. The classic batch type STR reactions used for enzymatic cellulose hydrolysis prevent these goals to be fulfilled...

  7. Occurrence of the Bunsen side reaction in the sulfur-iodine thermochemical cycle for hydrogen production

    Institute of Scientific and Technical Information of China (English)

    Qiao-qiao ZHU; Yan-wei ZHANG; Zhi YING; Jun-hu ZHOU; Zhi-hua WANG; Ke-fa CEN

    2013-01-01

    This study aimed to establish a closed-cycle operation technology with high thermal efficiency in the thermochemical sulfur-iodine cycle for large-scale hydrogen production.A series of experimental studies were performed to investigate the occurrence of side reactions in both the H2SO4 and HIx phases from the H2SO4/HI/I2/H2O quaternary system within a constant temperature range of 323-363 K.The effects of iodine content,water content and reaction temperature on the side reactions were evaluated.The results showed that an increase in the reaction temperature promoted the side reactions.However,they were prevented as the iodine or water content increased.The occurrence of side reactions was faster in kinetics and more intense in the H2SO4 phase than in the HIx phase.The sulfur or hydrogen sulfide formation reaction or the reverse Bunsen reaction was validated under certain conditions.

  8. Optimization and kinetic studies of sea mango (Cerbera odollam) oil for biodiesel production via supercritical reaction

    International Nuclear Information System (INIS)

    Highlights: • Sea mango oil as feedstock for biodiesel via non-catalytic supercritical reaction. • Extracted sea mango oil with high FFA could produce high yield of FAME. • Employment of Response Surface Methodology for optimization of FAME. • Kinetic study for reversible transesterification and esterification reactions. - Abstract: Sea mango (Cerbera odollam) oil, which is rich in free fatty acids, was utilized to produce fatty acid methyl esters (FAME) via supercritical transesterification reaction. Sea mango oil was extracted from seeds and was subsequently reacted with methanol in a batch-type supercritical reactor. Response surface methodology (RSM) analysis was used to optimize important parameters, including reaction temperature, reaction time and the molar ratio of methanol to oil. The optimum conditions were found as 380 °C, 40 min and 45:1 mol/mol, respectively, to achieve 78% biodiesel content. The first kinetic modelling of FAME production from sea mango oil incorporating reversible transesterification and reversible esterification was verified simultaneously. The kinetic parameters, including reaction rate constants, k, the pre-exponential constant, A, and the activation energy, Ea, for transesterification and esterification were determined using an ordinary differential equation (ODE45) solver. The highest activation energy of 40 kJ/mol and the lowest reaction rate constant of 2.50 × 10−5 dm3/mol s verified that the first stepwise reaction of TG to produce DG was the rate-limiting step

  9. Thermal decomposition of fission product nitrates and their reaction with glass batch additives Part A

    International Nuclear Information System (INIS)

    Thermal decomposition of fission product nitrates constituting a 'Purex' waste and their reaction with silica, alumina and aluminosilicate (Al2O3.2SiO2) have been studied. Oxides of nitrogen may be released from fission product nitrates in the temperature range (150 - 850degC) either due to their thermal decomposition or due to the reaction of alkali nitrates with silica or alumina of the glass batch additives. Fission product nitrates, CaNO3 and RbNO3 excepting, react very slowly with silica, the principal glass forming additive for a silicate glass, at temperatures of 1000degC. Complete reaction of Gr.II-Gr.IV metal nitrates with silica may be achieved at temperatures of 1400degC which is too high for a fission product immobilisation process. The alkali nitrates react very rapidly with boric oxide, silica, alumina and metakaolin (Al2O3.2SiO2) at subsolidus temperatures forming the alkali metaborate, alkali disilicate, alkali monoaluminate and alkali alumino disilicate respectively. A phenomenological description of the heating-up processes for fission product nitrate with silicate glass batch additives has been included. It has been very strongly recommended, that, if a silicate matrix is selected for incorporation of fission products, the glass melting should be carried out until a homogeneous or nearly homogeneous product is obtained and should not be stopped at a stage where a sintered or semivitreous mass is the resultant product. (author)

  10. Dietary Maillard reaction products and their fermented products reduce cardiovascular risk in an animal model.

    Science.gov (United States)

    Oh, N S; Park, M R; Lee, K W; Kim, S H; Kim, Y

    2015-08-01

    This study examined the effects of Maillard reaction products (MRP) and MRP fermented by lactic acid bacteria on antioxidants and their enhancement of cardiovascular health in ICR mouse and rat models. In previous in vitro studies, the selected lactic acid bacteria were shown to significantly affect the activity of MRP. The expression of genes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) related to antioxidant activity was upregulated by Maillard-reacted sodium caseinate (cMRP), and cMRP fermented by Lactobacillus fermentum H9 (F-cMRP) synergistically increased the expression of catalase and superoxide dismutase when compared with the high-cholesterol-diet group. Bleeding time, the assay for determination of antithrombotic activity, was significantly prolonged by Maillard-reacted whey protein concentration (wMRP) and wMRP fermented by Lactobacillus gasseri H10 (F-wMRP), similar to the bleeding time of the aspirin group (positive control). In addition, the acute pulmonary thromboembolism-induced mice overcame severe body paralysis or death in both the wMRP and the F-wMRP groups. In the serum-level experiment, cMRP and F-cMRP significantly reduced the serum total and low-density lipoprotein cholesterol levels and triglycerides but had only a slight effect on high-density lipoprotein cholesterol. The levels of aspartate transaminase and alanine transaminase also declined in the cMRP and F-cMRP intake groups compared with the high-cholesterol-diet group. In particular, F-cMRP showed the highest reducing effects on triglycerides, aspartate transaminase, and alanine transaminase. Moreover, the expression of cholesterol-related genes in the F-cMRP group demonstrated greater effects than for the cMRP group in the level of cholesterol 7 α-hydroxylase (CYP7A1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), and low-density lipoprotein receptors compared with the high-cholesterol-diet group. The protective role of cMRP and F-cMRP in the high

  11. Improved Products for Assimilation and Model Validation from the Atmospheric Infrared Sounder (AIRS) on Aqua

    Science.gov (United States)

    Pagano, Thomas S.

    2008-01-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 micrometer spectral region with spectral resolution of better than 1200. Key channels from the AIRS Level 1B calibrated radiance product are currently assimilated into operational weather forecasts at NCEP and other international agencies. Additional Level 2 products for assimilation include the AIRS cloud cleared radiances and the geophysical retrieved temperature and water vapor profiles. The AIRS products are also used to validate climate model vertical and horizontal biases and transport of water vapor and key trace gases including Carbon Dioxide and Ozone. The wide variety of products available from the AIRS make it well suited to study processes affecting the interaction of these products.

  12. Deterioration and shelf-life extension of fish and fishery products by modified atmosphere packaging

    Directory of Open Access Journals (Sweden)

    Payap Masniyom

    2011-04-01

    Full Text Available Fish and fishery products have been recognized as a nutrition source due to their high protein content. Moreover, theycontain considerable amount of unsaturated fatty acids, especially omega-3 fatty acids, which are regarded as preventivecompounds. However, shelf-life of seafood is limited by biochemical and microbiological changes. Modified atmospherepackaging (MAP is widely used for minimally processed fishery products including fresh meat for retarding microbial growthand enzymatic spoilage. CO2, O2, and N2 are most often used in MAP. CO2 enriched atmosphere inhibits the autolyticdegradation of fish muscle during storage. However, high levels of CO2 negatively affect product quality, especially by increasingdrip loss and altering texture. Development of satisfactory methods for shelf-life extension that ensure qualitymaintenance of products with minimum loss has drawn the attention of food technologists. The application of MAP andcombination process in seafood is a promising preservation method to extend the shelf-life of fish and fishery products.

  13. Neutral pion production in the 16O+27Al reaction at 94 MeV/nucleon

    International Nuclear Information System (INIS)

    The production of neutral pions in the reaction 16O+27Al at 94 MeV/nucleon was studied with a multidetector, which includes 180 BaF2 modules. Kinetic energy spectra for several laboratory angles were measured. The total cross section for neutral pion production was deduced. Results were compared with previous findings on charged pions from the same reaction at the same energy and with the prediction of a dynamical model based on the numerical solution of the Boltzmann-Nordheim-Vlasov equation

  14. Production of lactic acid from C6-polyols by alkaline hydrothermal reactions

    International Nuclear Information System (INIS)

    Production of lactic acid from C6-polyols (Mannitol) under alkaline hydrothermal conditions was investigated. Experiments were performed to examine the difference in the production of lactic acid between C6-polyols and C3-polyols (glycerine), as well as C6-aldoses (glucose). Results showed that the yield of lactic acid from C6-polyols was lower than that from both glycerine and glucose. It indicated that long chain polyols might follow a different reaction pathway from that of glycerine. Further investigation is needed to clarify the reaction mechanism and improve the relatively low lactic acid acid yield from C6-polyols.

  15. Some concepts of the advanced mass spectrometry at the COMBAS magnetic separator of nuclear reaction products

    International Nuclear Information System (INIS)

    Proposed is an in-flight measurement method of recoil nuclei masses with the help of a Penning trap located behind the COMBAS magnetic separator for nuclear reaction products. The method is based on the following operations: (i) Accepting the recoil nuclear reaction products by the magnetic separator and decreasing their kinetic energy by degraders. (ii) In-flight transportation of the retarded nuclei into the magnetic field of the Penning trap's solenoid and transforming their remaining longitudinal momentum into orbital rotation by the fringing magnetic field of the solenoid. (iii) Cooling the orbital rotation of the ions by the high-frequency azimuthal electric field of the Penning trap's electric hyperboloid. (orig.)

  16. Entrance Channel Dependence of Production Cross Sections of Superheavy Nuclei in Cold Fusion Reactions

    Institute of Scientific and Technical Information of China (English)

    FENG Zhao-Qing; JIN Gen-Ming; FU Fen; ZHANG Feng-Shou; JIA Fei; HUANG Xi; HU Rong-Jiang; LI Wen-Fei; LI Jun-Qing

    2005-01-01

    @@ Production cross sections of superheavy nuclei Rf and Hs for asymmetric and nearly symmetric projectile-target combinations are systematically studied within the framework of the dinuclear system model.The calculated results show that the production cross sections are strongly dependent on the symmetry of reaction systems.The obtained results are in good agreement with the available experimental data for asymmetric reaction systems.For nearly symmetric systems, the model gives opposite results with coupled channel model in which surface vibration and nucleon transfer are included.

  17. Impact of atmospheric nitrogen deposition on phytoplankton productivity in the South China Sea

    Science.gov (United States)

    Kim, Tae-Wook; Lee, Kitack; Duce, Robert; Liss, Peter

    2014-05-01

    The impacts of anthropogenic nitrogen (N) deposition on the marine N cycle are only now being revealed, but the magnitudes of those impacts are largely unknown in time and space. The South China Sea (SCS) is particularly subject to high anthropogenic N deposition, because the adjacent countries are highly populated and have rapidly growing economies. Analysis of data sets for atmospheric N deposition, satellite chlorophyll-a (Chl-a), and air mass back trajectories reveals that the transport of N originating from the populated east coasts of China and Indonesia, and its deposition to the ocean, has been responsible for the enhancements of Chl-a in the SCS. We found that atmospheric N deposition contributed approximately 20% of the annual biological new production in the SCS. The airborne contribution of N to new production in the SCS is expected to grow considerably in the coming decades.

  18. Reactions

    DEFF Research Database (Denmark)

    Søndergaard, Morten

    2011-01-01

    ) museum. Augmentation, in this expanding digital field, is part of a production of new public spaces, as well as a new reality that affects and traverses art and institutions immanently and througout. The expanding digital field is transforming art and the art museum in a number of fundamental ways, a few......; It is in this negotiation, I would claim, that the foundation of a possible critique of the role of the (art) museum in the age of post-bourgeois public space and experience-based culture should be located....

  19. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications

    OpenAIRE

    Jokinen, T; Berndt, T; Makkonen, R.; Kerminen, V-M; Junninen, H.; Paasonen, P.; Stratmann, F.; Herrmann, H.; Guenther, AB; Worsnop, DR; M. Kulmala; M. Ehn; Sipilä, M.

    2015-01-01

    Extremely low volatility organic compounds (ELVOC) are suggested to promote aerosol particle formation and cloud condensation nuclei (CCN) production in the atmosphere. We show that the capability of biogenic VOC (BVOC) to produce ELVOC depends strongly on their chemical structure and relative oxidant levels. BVOC with an endocyclic double bond, representative emissions from, e.g., boreal forests, efficiently produce ELVOC from ozonolysis. Compounds with exocyclic double bonds or acyclic comp...

  20. IR-BASED SATELLITE PRODUCTS FOR THE MONITORING OF ATMOSPHERIC WATER VAPOR OVER THE BLACK SEA

    OpenAIRE

    VELEA LILIANA; BOJARIU ROXANA

    2016-01-01

    The amount of precipitable water (TPW) in the atmospheric column is one of the important information used weather forecasting. Some of the studies involving the use of TPW relate to issues like lightning warning system in airports, tornadic events, data assimilation in numerical weather prediction models for short-range forecast, TPW associated with intense rain episodes. Most of the available studies on TPW focus on properties and products at global scale, with the drawback that regional cha...

  1. Rapid Aluminum Nanoparticle Production by Milling in NH₃ and CH₃NH₂ Atmospheres: An Experimental and Theoretical Study.

    Science.gov (United States)

    McMahon, Brandon W; Yu, Jiang; Boatz, Jerry A; Anderson, Scott L

    2015-07-29

    Ball milling of aluminum in gaseous atmospheres of ammonia and monomethylamine (MMA) was found to produce particles in the 100 nm size range with high efficiency. A combination of mass spectrometry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis with mass spectrometric product analysis (TGA-MS), scanning electron microscopy (SEM), infrared spectroscopy, and dynamic light scattering (DLS) was used to study the particles and the chemical interactions responsible for particle production. To help understand the nature of the surface chemistry, high level quantum chemical calculations were performed to predict the structures and energetics for binding and reactions of NH3 and MMA on aluminum surfaces. Both NH3 and MMA react with aluminum under milling conditions, producing H2 and other gaseous products, and leaving the surfaces functionalized. The surface functionalization enhances size reduction by reducing the surface free energy and the tendency toward mechanochemical welding. For both NH3 and MMA, the particle cores are metallic aluminum, but the surface chemical properties are quite different. The ammonia-milled particles are capped by an AlNxOyHz layer ∼10 nm thick, which passivates the particles. The MMA-milled particles are capped with a thinner passivating layer, such that they are pyrophoric in air and react with N2 at elevated temperatures. PMID:26132713

  2. Light charged-particle production in 96 MeV neutron-induced reactions on carbon and oxygen

    International Nuclear Information System (INIS)

    In recent years, an increasing number of applications involving fast neutrons have been developed or are under consideration, e.g. radiation treatment of cancer, neutron dosimetry at commercial aircraft altitudes, soft-error effects in computer memories, accelerator-driven transmutation of nuclear waste and energy production and determination of the response of neutron detectors. Data on light-ion production in light nuclei such as carbon, nitrogen and oxygen are particularly important in calculations of dose distributions in human tissue for radiation therapy at neutron beams, and for dosimetry of high-energy neutrons produced by high-energy cosmic radiation interacting with nuclei (nitrogen and oxygen) in the atmosphere. When studying neutron dose effects, it is especially important to consider carbon and oxygen, since they are, by weight, the most abundant elements in human tissue. Preliminary experimental double-differential cross sections of inclusive light-ion (p, d, t, 3He and α) production in carbon induced by 96-MeV neutrons have been presented. Energy spectra were measured at eight laboratory angles: 20, 40, 60, 80, 100, 120, 140 and 160 deg.. Measurements were performed at The Svedberg Laboratory (TSL), Uppsala, using the dedicated MEDLEY experimental setup. The authors have earlier reported experimental double-differential cross sections of inclusive light-ion production in oxygen. In this paper, the deduced kerma coefficients for oxygen has been presented and compared with reaction model calculations. (authors)

  3. Production of Zinc Borate for Pilot-Scale Equipment and Effects of Reaction Conditions on Yield

    Directory of Open Access Journals (Sweden)

    Melek BARDAKCI

    2013-05-01

    Full Text Available In this study, zinc borate (ZB was synthesized by reacting zinc oxide and boric acid in the presence of standard ZB (w/w, in terms of boric acid in order to promote crystallization. The effects of seed, H3BO3/ZnO (boric acid/zinc oxide ratio, reaction time, water volume, reaction temperature and cooling temperature on yield were investigated for pilot-scale equipment. The results indicated that the addition of seed (w/w to a saturated solution of reactants increased the yield of the reaction. The results of reaction yields obtained from either magnetically or mechanically stirred systems were compared. At various reaction times, the optimal yield was 86.78 % in a saturated aqueous solution. The products were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR and Thermogravimetric / Differential Thermal Analysis (TG/DTA. The results displayed that ZB was successfully produced under the optimized reaction conditions and the product synthesized had high thermal stability.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4432

  4. Determination of 68Ga production parameters by different reactions using ALICE and TALYS codes

    Indian Academy of Sciences (India)

    Mahdi Sadeghi; Tayeb Kakavand; Leila Mokhtari; Zohreh Gholamzadeh

    2009-02-01

    Gallium-68 (1/2 = 68 min, + = 89%) is an important positron-emitting radionuclide for positron emission tomography and used in nuclear medicine for diagnosing tumours. This study gives a suitable reaction to produce 68Ga. Gallium-68 excitation function via 68Zn(, ) 68Ga, 68Zn(, 2) 68Ga, 70Zn(, 3) 68Ga and 65Cu(, ) 68Ga reactions were calculated by ALICE-91 and TALYS-1.0 codes. The calculated excitation function of 68Zn(, ) 68Ga reaction was compared with the reported measurement and evaluations. Requisite thickness of the targets was obtained by SRIM code for each reaction. The 68Ga production yield was evaluated using excitation function and stopping power.

  5. Characterization of the products formed by the reaction of trichlorocyanuric acid with 2-propanol.

    Science.gov (United States)

    Sandercock, P Mark L; Barnett, Julie S

    2009-11-01

    We report a recent investigation into the death of a cat that was initially thought to involve intentionally burning the animal via the use of an ignitable liquid. The exposure of the animal to flame was ruled out. Instead, forensic investigation revealed the intentional mixing together of a common outdoor swimming pool chlorinator, trichlorocyanuric acid (TCCA), and 2-propanol (aka, isopropyl alcohol or rubbing alcohol). The reaction of these two chemicals resulted in the formation of cyanuric acid residue, hydrochloric acid, and the evolution of a significant volume of chlorine gas. Further alpha-chlorination side reactions also occurred between 2-propanol and TCCA to produce a variety of chlorinated 2-propanone species that were detected on the submitted evidence. The identification of the products of both the main reaction and the side reactions allowed the authors to determine what chemicals were originally mixed together by the culprit. PMID:19818110

  6. Food Processing and Maillard Reaction Products: Effect on Human Health and Nutrition

    Directory of Open Access Journals (Sweden)

    Nahid Tamanna

    2015-01-01

    Full Text Available Maillard reaction produces flavour and aroma during cooking process; and it is used almost everywhere from the baking industry to our day to day life to make food tasty. It is often called nonenzymatic browning reaction since it takes place in the absence of enzyme. When foods are being processed or cooked at high temperature, chemical reaction between amino acids and reducing sugars leads to the formation of Maillard reaction products (MRPs. Depending on the way the food is being processed, both beneficial and toxic MRPs can be produced. Therefore, there is a need to understand the different types of MRPs and their positive or negative health effects. In this review we have summarized how food processing effects MRP formation in some of the very common foods.

  7. Acid-Catalyzed Transesterification Reaction of Beef Tallow For Biodiesel Production By Factor Variation

    Directory of Open Access Journals (Sweden)

    R.C. Ehiri

    2014-07-01

    Full Text Available Biodiesel is a diesel grade fuel made by transesterification reaction of vegetable oils and animal fats with alcohol. Three variable factors that affect the yield of biodiesel namely, reaction time, reaction temperature and catalyst concentration were studied in this work. The biodiesel was produced via a batchprocess acid-catalyzed transesterification reaction of beef tallow with methanol. Optimal conditions for the reaction were established in a three factor two-level (23 central composite design with the biodiesel pretreatment yield as the response surface. The results show that the mean yield of biodiesel was 92.04% with a standard deviation of 5.16. An optimal biodiesel yield of 96.30% occurred at 0.5% HCl catalyst concentration and at constant conditions of 1.5h reaction time, 60oC reaction temperature and 6:1 methanol: tallow volume ratio. Gas chromatographic analysis of the beef tallow identified palmitic, stearic and oleic acids in it while the fatty acid methyl esters in the biodiesel product were oleate and linoleate. Catalysis was the most significant factor in the transesterification process.

  8. Measurement of the rates of reaction of the ground and metastable excited states of 02+, N0+ and 0+ with atmospheric gases at thermal energy

    International Nuclear Information System (INIS)

    Thermal-energy reaction rate coefficients and product ion distributions have been measured for reactions of both the ground state and metastable electronic states of 02+, N0+ and 0+ with several neutral species, using a selected-ion flow tube. In general the excited-ion reaction rates are fast, frequently approaching the Langevin limit. Collisional quenching occurs for the reactions of N0+sup(star) with N2,02 and H2 and the quenching rates have been determined. The ion source also provided a substantial yield of doubly charged 02 permitting some measurements of reaction rates of 022+. (author)

  9. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems

    International Nuclear Information System (INIS)

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes

  10. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems.

    Science.gov (United States)

    Oßwald, Patrick; Köhler, Markus

    2015-10-01

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes. PMID:26520986

  11. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems

    Science.gov (United States)

    Oßwald, Patrick; Köhler, Markus

    2015-10-01

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes.

  12. Chemoselective reaction of cyanoacetic acid with benzal-4-acetylanilines and fungitoxicity of products

    Indian Academy of Sciences (India)

    Anjali Sidhu; J R Sharma; Mangat Rai

    2009-07-01

    Cyanoacetic acid reacted chemoselectively with carbon-nitrogen double bond of benzal-4-acetylaniliines, leaving the carbon-oxygen double bond, considered to be more reactive, intact, leading to the formation of mono addition-elimination products rather than bis attack at both the reactive centres, even when the reaction was carried out with two moles of cyanoacetic acid. The product viz. benzalcyanoacetic acid and its derivatives were screened for their fungitoxicity against five pathogenic fungi.

  13. Terbium-149 for nuclear medicine. The production of 149Tb via heavy ions induced nuclear reactions

    International Nuclear Information System (INIS)

    Experimental results on the production and separation of 149Tb from natural neodymium target using the nuclear process Nd(12C,xn)149Dy → 149Tb are presented. Terbium-149 was produced at the U-200 cyclotron of FLNR JINR by irradiating natNd2O3 with 12C ions and its possible production for nuclear medicine utilising the heavy-ion induced reactions was investigated. (author)

  14. Expected production of new exotic α emitters 108Xe and 112Ba in complete fusion reactions

    Science.gov (United States)

    Kalandarov, Sh. A.; Adamian, G. G.; Antonenko, N. V.; Wieleczko, J. P.

    2016-05-01

    The production cross sections of neutron-deficient isotopes Xe-110108 and Ba-114112 in the complete fusion reactions Ni,5658+54Fe and Ni,5658+58Ni with stable and radioactive beams are studied with the dinuclear system model. The calculated results are compared with the available experimental data. The optimal beam energies and corresponding maximum production cross sections of new isotopes 108Xe and 112Ba are predicted.

  15. Modeling Chemical Growth Processes in Titan's Atmosphere: 1. Theoretical Rates for Reactions between Benzene and the Ethynyl (C2H) and Cyano (CN) Radicals at Low Temperature and Pressure

    Science.gov (United States)

    Woon, David E.

    2006-01-01

    Density functional theory calculations at the B3LYP/6-31+G** level were employed to characterize the critical points for adducts, isomers, products, and intervening transition states for the reactions between benzene and the ethynyl (C2H) or cyano (CN) radicals. Both addition reactions were found to have no barriers in their entrance channels, making them efficient at the low temperature and pressure conditions that prevail in the haze-forming region of Titan's atmosphere as well as in the dense interstellar medium (ISM). The dominant products are ethynylbenzene (C6H5C2H) and cyanobenzene (C6H5CN). Hydrogen abstraction reactions were also characterized but found to be non-competitive. Trajectory calculations based on potentials fit to about 600 points calculated at the ROMP2/6-31+G** level for each interaction surface were used to determine reaction rates. The rates incorporated any necessary corrections for back reactions as ascertained from a multiwell treatment used to determine outcome distributions over the range of temperatures and pressures pertinent to Titan and the ISM and are in good agreement with the limited available experimental data.

  16. Characterization of ionic liquid‐based biocatalytic two‐phase reaction system for production of biodiesel

    DEFF Research Database (Denmark)

    Prabhavathi Devi, Bethala Lakshmi Anu; Guo, Zheng; Xu, Xuebing

    2011-01-01

    The property of a variety of ionic liquids (ILs) as reaction media was evaluated for the production of biodiesel by enzymatic methanolysis of rapeseed oil. The IL Ammoeng 102, containing tetraaminum cation with C18 acyl and oligoethyleneglycol units, was found to be capable of forming oil....../IL biphasic reaction system by mixing with substrates, which is highly effective for the production of biodiesel with more than 98% biodiesel yield and nearly 100% conversion of oil. Conductor‐like screening model for real solvent (COSMO‐RS) in silico prediction of substrate solubility and simulation...... of partition coefficient change vs. reaction evolution indicated that the amphiphilic property of Ammoeng 102 might be responsible for creating efficient interaction of immiscible substrates; while big difference of partition coefficients of generated biodiesel and glycerol between the two phases suggests...

  17. Estimate of production of medical isotopes by photo-neutron reaction at the Canadian Light Source

    International Nuclear Information System (INIS)

    In contrast to conventional bremsstrahlung photon beam sources, laser backscatter photon sources at electron synchrotrons provide the capability to selectively tune photons to energies of interest. This feature, coupled with the ubiquitous giant dipole resonance excitations of atomic nuclei, promises a fertile method of nuclear isotope production. In this article, we present the results of simulations of production of the medical/industrial isotopes 196Au, 192Ir and 99Mo by (γ,n) reactions. We employ FLUKA Monte Carlo code along with the simulated photon flux for a beamline at the Canadian Light Source in conjunction with a CO2 laser system. -- Highlights: •We estimate production of medical isotopes by photo-neutron reaction. •Recently developed simulation code for generating laser backscattering photons at the CLS storage ring is described and used. •We describe the preliminary Monte Carlo simulations (using FLUKA code) for the production of 99Mo, 196Au and 192Ir isotopes. •The simulations demonstrate that the medical isotopes 99Mo, 192Ir and 196Au are the main products of photonuclear reaction on 100Mo, 193Ir and 197Au targets. •The present results agree with the evaluated and observed radioactive isotope production rates in RPIT experiment

  18. Evaluation of gamma ray production cross sections and spectra for neutron induced reactions on Chromium

    International Nuclear Information System (INIS)

    An evaluation of photon production cross sections and relevant spectra is described, referring to neutron induced reactions on *H5*H0CR, *H5*H2CR, *H5*H4CR and sup(nat)CR in the energy range 100 KEV-8MEV

  19. Characterization of cement minerals, cements and their reaction products at the atomic and nano scale

    DEFF Research Database (Denmark)

    Skibsted, Jørgen; Hall, Christopher

    2008-01-01

    Recent advances and highlights in characterization methods are reviewed for cement minerals, cements and their reaction products. The emphasis is on X-ray and neutron diffraction, and on nuclear magnetic resonance methods, although X-ray absorption and Raman spectroscopies are discussed briefly...

  20. Production of neutron-rich isotopes in transfer-type reactions

    International Nuclear Information System (INIS)

    The production yields of new neutron-rich 84,86Zn and 90,92Ge isotopes beyond N=50 and isotopes of nuclei with charge numbers Z=64-80 are estimated for future experiments in the multinucleon transfer reactions at energies close to the Coulomb barrier. (author)

  1. Bottom excitation contribution to dilepton production in ν, anti ν reactions

    International Nuclear Information System (INIS)

    Bottom production in ν and anti ν deep inelastic reactions is discussed within the framework of the standard model for quarks and leptons. Using the Kobayashi-Maskawa model it is found that dilepton events available at present can have a bottom contribution which can be as high as 10% (upper bound)

  2. A new branch of advertising: reviewing factors that influence reactions to product placement

    NARCIS (Netherlands)

    E. van Reijmersdal; P. Neijens; E.G. Smit

    2009-01-01

    This iiterature review presents a quantitative synthesis of 57 studies on product placement and shows which factors are most effective, it shows that placement characteristics, such as placement commerciality, modality, and prominence, have a strong impact on audience reactions. Audience characteris

  3. Holocene primary productivity and the atmosphere/ocean linkage in the Gulf of Alaska

    Science.gov (United States)

    Addison, J. A.; Finney, B.; Anderson, L.; Barron, J. A.; Hayes, S. M.; Sliwinski, M.; Mix, A. C.

    2015-12-01

    Recent work in the temperate fjords of the Gulf of Alaska, located in the subarctic northeast Pacific Ocean, has demonstrated a positive link between modern atmosphere/ocean dynamics and accumulation of biogenic sediments during the last 100 years, where intensified Aleutian Low atmospheric pressure cell regimes correspond to peaks in export primary productivity (Addison et al., 2013). Here, this work is extended by examining the last 7500 years of biogenic sedimentation from marine sediment core EW0408-33JC (57.16°N, 135.36°W, 144 m water depth), which is constrained by 17 age-control points spaced every ~500 years. We use bromine (Br) intensities measured by core-scanning XRF with a 2-mm sampling resolution as a geochemical proxy for past primary productivity. These Br intensities are calibrated to organic Br concentrations using a combination of quantitative WD-XRF methods and synchrotron-radiation Br speciation studies, with cross-verification provided by low-resolution analyses of other productivity proxies, including biogenic silica (opal), total organic carbon (TOC), and organic matter δ13C ratios. Our findings indicate distinct centennial-to-millennial changes, with positive productivity excursions between 7500-7000, 6500-6000, 5000-3500, 2500-1500, and 1000-500 INTCAL13 yr BP. We compare the timing of these excursions against a compilation of marine and terrestrial paleoclimate records sensitive to forcing by the Aleutian Low to determine if the positive relationship between atmosphere/ocean dynamics and marine primary productivity has remained consistent over the last 7500 years. Other potential forcing mechanisms (e.g., solar insolation, irradiance) are also considered. Reference: Addison, J.A., Finney, B., Jaeger, J., Stoner, J., Norris, R., & Hangsterfer, A., 2013, Integrating satellite observations and modern climate measurements with the recent sedimentary record: an example from Southeast Alaska. JGR-Oceans, v. 118, 18 pgs.

  4. The reaction products of sulfide and S-nitrosoglutathione are potent vasorelaxants.

    Science.gov (United States)

    Berenyiova, Andrea; Grman, Marian; Mijuskovic, Ana; Stasko, Andrej; Misak, Anton; Nagy, Peter; Ondriasova, Elena; Cacanyiova, Sona; Brezova, Vlasta; Feelisch, Martin; Ondrias, Karol

    2015-04-30

    The chemical interaction of sodium sulfide (Na2S) with the NO-donor S-nitrosoglutathione (GSNO) has been described to generate new reaction products, including polysulfides and nitrosopersulfide (SSNO(-)) via intermediacy of thionitrous acid (HSNO). The aim of the present work was to investigate the vascular effects of the longer-lived products of the Sulfide/GSNO interaction. Here we show that the products of this reaction relax precontracted isolated rings of rat thoracic aorta and mesenteric artery (but to a lesser degree rat uterus) with a >2-fold potency compared with the starting material, GSNO (50 nM), whereas Na2S and polysulfides have little effect at 1-5 µM. The onset of vasorelaxation of the reaction products was 7-10 times faster in aorta and mesenteric arteries compared with GSNO. Relaxation to GSNO (100-500 nM) was blocked by an inhibitor of soluble guanylyl cyclase, ODQ (0.1 and 10 µM), and by the NO scavenger cPTIO (100 µM), but less affected by prior acidification (pH 2-4), and unaffected by N-acetylcysteine (1 mM) or methemoglobin (20 µM heme). By contrast, relaxation to the Sulfide/GSNO reaction products (100-500 nM based on the starting material) was inhibited to a lesser extent by ODQ, only slightly decreased by cPTIO, more markedly inhibited by methemoglobin and N-acetylcysteine, and abolished by acidification before addition to the organ bath. The reaction mixture was found to generate NO as detected by EPR spectroscopy using N-(dithiocarboxy)-N-methyl-D-glucamine (MGD2)-Fe(2+) as spin trap. In conclusion, the Sufide/GSNO reaction products are faster and more pronounced vasorelaxants than GSNO itself. We conclude that in addition to NO formation from SSNO(-), reaction products other than polysulfides may give rise to nitroxyl (HNO) and be involved in the pronounced relaxation induced by the Sulfide/GSNO cross-talk. PMID:25529482

  5. Gas phase formation of extremely oxidized pinene reaction products in chamber and ambient air

    Directory of Open Access Journals (Sweden)

    M. Ehn

    2012-02-01

    Full Text Available High molecular weight (300–650 Da naturally charged negative ions have previously been observed at a boreal forest site in Hyytiälä, Finland. The long-term measurements conducted in this work showed that these ions are observed practically every night during spring and summer in Hyytiälä. The ambient mass spectral patterns could be reproduced in striking detail during additional measurements of α-pinene (C10H16 oxidation at low-OH conditions in the Jülich Plant Atmosphere Chamber (JPAC. The ions were identified as clusters of the nitrate ion (NO3 and α-pinene oxidation products reaching oxygen to carbon ratios of 0.7–1.3, while retaining most of the initial ten carbon atoms. Attributing the ions to clusters instead of single molecules was based on additional observations of the same extremely oxidized organics in clusters with HSO4 (Hyytiälä and C3F5O2 (JPAC. The most abundant products in the ion spectra were identified as C105H14O7, C10H14O9, C10H16O9, and C10H14O11. The mechanism responsible for forming these molecules is still not clear, but the initial reaction is most likely ozone attack at the double bond, as the ions are mainly observed under dark conditions. β-pinene also formed highly oxidized products under the same conditions, but less efficiently, and mainly C9 compounds which were not observed in Hyytiälä, where β-pinene on average is 4–5 times less abundant than α-pinene. Further, to explain the high O/C together with the relatively high H/C, we propose that geminal diols and/or hydroperoxide groups may be important. We estimate that the night-time concentration of the sum of the neutral extremely oxidized products is on the order of 0.1–1 ppt (~10

  6. Gas phase formation of extremely oxidized pinene reaction products in chamber and ambient air

    Directory of Open Access Journals (Sweden)

    M. Ehn

    2012-06-01

    Full Text Available High molecular weight (300–650 Da naturally charged negative ions have previously been observed at a boreal forest site in Hyytiälä, Finland. The long-term measurements conducted in this work showed that these ions are observed practically every night between spring and autumn in Hyytiälä. The ambient mass spectral patterns could be reproduced in striking detail during additional measurements of α-pinene (C10H16 oxidation at low-OH conditions in the Jülich Plant Atmosphere Chamber (JPAC. The ions were identified as clusters of the nitrate ion (NO3 and α-pinene oxidation products reaching oxygen to carbon ratios of 0.7–1.3, while retaining most of the initial ten carbon atoms. Attributing the ions to clusters instead of single molecules was based on additional observations of the same extremely oxidized organics in clusters with HSO4 (Hyytiälä and C3F5O2 (JPAC. The most abundant products in the ion spectra were identified as C10H14O7, C10H14O9, C10H16O9, and C10H14O11. The mechanism responsible for forming these molecules is still not clear, but the initial reaction is most likely ozone attack at the double bond, as the ions are mainly observed under dark conditions. β-pinene also formed highly oxidized products under the same conditions, but less efficiently, and mainly C9 compounds which were not observed in Hyytiälä, where β-pinene on average is 4–5 times less abundant than α-pinene. Further, to explain the high O/C together with the relatively high H/C, we propose that geminal diols and/or hydroperoxide groups may be important. We estimate that the night-time concentration of the sum of the neutral extremely oxidized products is on the order of 0.1–1 ppt (~10

  7. Redox reaction of aqueous selenite with As-rich pyrite from Jiguanshan ore mine (China): Reaction products and pathway

    International Nuclear Information System (INIS)

    Highlights: • Arsenic local environment in As-rich pyrite sample is very close to arsenopyrite. • Se(0) was the main reduction product when Se(IV) reacted with As-rich natural pyrite at pH 5.05–8.65. • Release of the As impurity via arsenopyrite oxidation is preferential for As-rich pyrite dissolution. - Abstract: The interaction of an As-rich natural pyrite (FeS2.08As0.043) with aqueous Se(IV) was investigated as a function of pH, ferrous iron concentration, and reaction time. Arsenic is often the most abundant minor constituent of natural pyrite, and is believed to substitute for S in the pyrite structure. EXAFS measurements confirmed the presence of AsS dianion group, with arsenic in the same local configuration as in the arsenopyrite. Speciation studies indicated that Se(0) was the unique reduction product in the pH range 5.05–8.65 over a reaction period of >1 month, while trace amounts of FeSeO3 might be formed at pH ⩾ 6.10. At pH > 6.07, the formation of Fe(III)-(oxyhydr)oxide is kinetically favored, and it consumed nearly all the aqueous iron, including the extra added Fe2+, thereby inhibiting the formation of the thermodynamically most stable product: FeSe2. After oxidation by Se(IV), the occurrence of surface S0, significant aqueous sulfur deficit, and excessive leaching of arsenic in solution, indicate the preferential release of As impurity via arsenopyrite oxidation. The data suggest that the polysulfide-elemental sulfur pathway, which prevails in acid-soluble metal sulfides, is an important pathway in the oxidation of As-rich pyrite, in addition to the thiosulfate pathway for acid-insoluble pyrite. Control experiments on As-free natural pyrite further support this mechanism. This study confirms the potential of reductive precipitation to attenuate the mobility of Se in the environment and demonstrates that minor elements commonly present in natural pyrite can play a significant role on its dissolution pathway

  8. Product Branching Ratios of the Reaction of CO with H3+ and H2D+

    International Nuclear Information System (INIS)

    The reaction of CO with H3+ and H2D+ has been studied to investigate thermal rate coefficients and product branching ratios in the temperature range (20, 350) K, by using a direct ab initio molecular dynamics method. In trajectory simulations, the energies and forces are calculated using a scaling all correlation second-order Moeller-Plesset perturbation theory (SAC-MP2) method with the correlation consistent polarized valence triplet-zeta basis (cc-pVTZ). Results show that total thermal rate coefficients for both the CO + H3+and the CO + H2D+ reactions have a weakly positive temperature dependence. At room temperature, the rate coefficients are predicted to be (1.42 ± 0.03) x 10-9 cm3 molecule-1 s-1 with a product branching ratio of (HOC+)/(HCO+) = 0.36 ± 0.01 for the CO + H3+ reaction, and (1.26 ± 0.03) x 10-9 cm3 molecule-1 s-1 with the product branching ratios: 0.37 ± 0.01 (((HOC+) + (DOC+))/((HCO+) + (DOC+))), 0.54 ± 0.02 ((DCO+)/(HCO+)), and 0.49 ± 0.02 ((DOC+)/(HOC+)) for CO + H2D+. The product branching ratios have a noticeable temperature dependence as well as a pronounced isotopic effect for the H/DOC+ product channel.

  9. Near-threshold production of neutral π mesons in heavy-ion reactions

    International Nuclear Information System (INIS)

    Energy and angular distributions of neutral π mesons emitted in reactions of 35-MeV/u 14N + A1, Ni, and W have been measured by using beams from the MSU K = 500 cyclotron. The measurements continue a long tradition of subthreshold (in the nucleon-nucleon sense) production of π mesons, extending back to the first artificial production by Gardner and Lattes using 75-MeV/u α-particle beams from the UCRL 184'' synchrocyclotron. Comparisons are made with theory, ascribing the present production to mechanisms of varying degree of collectivity, and some suggestions are made concerning future experimental work. 34 references

  10. Hydroxyl-radical production in physiological reactions. A novel function of peroxidase.

    Science.gov (United States)

    Chen, S X; Schopfer, P

    1999-03-01

    Peroxidases catalyze the dehydrogenation by hydrogen peroxide (H2O2) of various phenolic and endiolic substrates in a peroxidatic reaction cycle. In addition, these enzymes exhibit an oxidase activity mediating the reduction of O2 to superoxide (O2.-) and H2O2 by substrates such as NADH or dihydroxyfumarate. Here we show that horseradish peroxidase can also catalyze a third type of reaction that results in the production of hydroxyl radicals (.OH) from H2O2 in the presence of O2.-. We provide evidence that to mediate this reaction, the ferric form of horseradish peroxidase must be converted by O2.- into the perferryl form (Compound III), in which the haem iron can assume the ferrous state. It is concluded that the ferric/perferryl peroxidase couple constitutes an effective biochemical catalyst for the production of .OH from O2.- and H2O2 (iron-catalyzed Haber-Weiss reaction). This reaction can be measured either by the hydroxylation of benzoate or the degradation of deoxyribose. O2.- and H2O2 can be produced by the oxidase reaction of horseradish peroxidase in the presence of NADH. The .OH-producing activity of horseradish peroxidase can be inhibited by inactivators of haem iron or by various O2.- and .OH scavengers. On an equimolar Fe basis, horseradish peroxidase is 1-2 orders of magnitude more active than Fe-EDTA, an inorganic catalyst of the Haber-Weiss reaction. Particularly high .OH-producing activity was found in the alkaline horseradish peroxidase isoforms and in a ligninase-type fungal peroxidase, whereas lactoperoxidase and soybean peroxidase were less active, and myeloperoxidase was inactive. Operating in the .OH-producing mode, peroxidases may be responsible for numerous destructive and toxic effects of activated oxygen reported previously. PMID:10103001

  11. Ozone deposition velocities, reaction probabilities and product yields for green building materials

    Science.gov (United States)

    Lamble, S. P.; Corsi, R. L.; Morrison, G. C.

    2011-12-01

    Indoor surfaces can passively remove ozone that enters buildings, reducing occupant exposure without an energy penalty. However, reactions between ozone and building surfaces can generate and release aerosols and irritating and carcinogenic gases. To identify desirable indoor surfaces the deposition velocity, reaction probability and carbonyl product yields of building materials considered green (listed, recycled, sustainable, etc.) were quantified. Nineteen separate floor, wall or ceiling materials were tested in a 10 L, flow-through laboratory reaction chamber. Inlet ozone concentrations were maintained between 150 and 200 ppb (generally much lower in chamber air), relative humidity at 50%, temperature at 25 °C and exposure occurred over 24 h. Deposition velocities ranged from 0.25 m h -1 for a linoleum style flooring up to 8.2 m h -1 for a clay based paint; reaction probabilities ranged from 8.8 × 10 -7 to 6.9 × 10 -5 respectively. For all materials, product yields of C 1 thru C 12 saturated n-aldehydes, plus acetone ranged from undetectable to greater than 0.70 The most promising material was a clay wall plaster which exhibited a high deposition velocity (5.0 m h -1) and a low product yield (

  12. Transfer products from the reactions of heavy ions with heavy nuclei

    International Nuclear Information System (INIS)

    Production of nuclides heavier than the target from 86Kr- and 136Xe-induced reactions with 181Ta and 238U was investigated. Attempts were made to produce new neutron-excess Np and Pu isotopes by the deep inelastic mechanism. No evidence was found for 242Np or 247Pu. Estimates were made for the production of 242Np, 247Pu, and 248Am from heavy-ion reactions with uranium targets. Comparisons of reactions of 86Kr and 136Xe ions with thick 181Ta targets and 86Kr, 136Xe and 238U ions with thick 238U targets indicate that the most probable products are not dependent on the projectile. The most probable products can be predicted by the equation Z - Z/sub target/ = 0.43 (A - A/sub target/) + 1.0. The major effect of the projectile is the magnitude of the production cross section of the heavy products. Based on these results, estimates are made of the most probable mass of element 114 produced from heavy-ion reactions with 248Cm and 254Es targets. These estimates give the mass number of element 114 as approx. 287 if produced in heavy-ion reactions with these very heavy targets. Excitation functions of gold and bismuth isotopes arising from 86Kr- and 136Xe-induced reactions with thin 181Ta targets were measured. These results indicate that the shape and location (in Z and A above the target) of the isotopic distributions are not strongly dependent on the projectile incident energy. Also, the nuclidic cross sections are found to increase with an increase in projectile energy to a maximum at approximately 1.4 to 1.5 times the Coulomb barrier. Above this maximum, the nuclidic cross sections are found to decrease with an increase in projectile energy. This decrease in cross section is believed to be due to fission of the heavy products caused by high excitation energy and angular momentum. 111 references, 39 figures, 34 tables

  13. Independent Verification of Element 114 Production in the 48Ca+242Pu Reaction

    International Nuclear Information System (INIS)

    Independent verification of the production of element 114 in the reaction of 244-MeV 48Ca with 242Pu is presented. Two chains of time- and position-correlated decays have been assigned to 286114 and 287114. The observed decay modes, half-lives, and decay energies agree with published results. The measured cross sections at a center-of-target energy of 244 MeV for the 242Pu(48Ca,3-4n)287,286114 reactions were 1.4-1.2+3.2 pb each, which are lower than the reported values.

  14. Influence of the corrosion products of copper on its atmospheric corrosion kinetics in tropical climate

    International Nuclear Information System (INIS)

    In the present paper, the identification of the corrosion product phases formed on copper under different atmospheres of Cuban tropical climate is reported. Cuprite (Cu2O), paratacamite (Cu2Cl(OH)3), posnjakite (Cu4SO4(OH)6 · 2H2O) and brochantite (Cu4SO4(OH)6) were the main phases identified by X-ray diffraction (XRD) analysis and Fourier transform infrared spectroscopy (FTIR). Copper corrosion products are known to have a protective effect against corrosion. However, a different behaviour was obtained under sheltered coastal conditions. This can be due to the corrosion products morphology and degree of crystallisation, rather than their phase composition. A higher time of wetness and the accumulation of pollutants not washed away from the metal surface can also play an important role

  15. Atmospheric emissions and air quality impacts from natural gas production and use.

    Science.gov (United States)

    Allen, David T

    2014-01-01

    The US Energy Information Administration projects that hydraulic fracturing of shale formations will become a dominant source of domestic natural gas supply over the next several decades, transforming the energy landscape in the United States. However, the environmental impacts associated with fracking for shale gas have made it controversial. This review examines emissions and impacts of air pollutants associated with shale gas production and use. Emissions and impacts of greenhouse gases, photochemically active air pollutants, and toxic air pollutants are described. In addition to the direct atmospheric impacts of expanded natural gas production, indirect effects are also described. Widespread availability of shale gas can drive down natural gas prices, which, in turn, can impact the use patterns for natural gas. Natural gas production and use in electricity generation are used as a case study for examining these indirect consequences of expanded natural gas availability. PMID:24498952

  16. An Investigation of the Complexity of Maillard Reaction Product Profiles from the Thermal Reaction of Amino Acids with Sucrose Using High Resolution Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Agnieszka Golon

    2014-08-01

    Full Text Available Thermal treatment of food changes its chemical composition drastically with the formation of “so-called” Maillard reaction products, being responsible for the sensory properties of food, along with detrimental and beneficial health effects. In this contribution, we will describe the reactivity of several amino acids, including arginine, lysine, aspartic acid, tyrosine, serine and cysteine, with carbohydrates. The analytical strategy employed involves high and ultra-high resolution mass spectrometry followed by chemometric-type data analysis. The different reactivity of amino acids towards carbohydrates has been observed with cysteine and serine, resulting in complex MS spectra with thousands of detectable reaction products. Several compounds have been tentatively identified, including caramelization reaction products, adducts of amino acids with carbohydrates, their dehydration and hydration products, disproportionation products and aromatic compounds based on molecular formula considerations.

  17. Cosmic-ray induced production of radioactive noble gases in the atmosphere, ground, and seawater

    International Nuclear Information System (INIS)

    This paper describes the development of an MCNP6 model and a suite of supporting MATLAB scripts being developed to conduct detailed studies of the radioactive noble gas background activity concentrations resulting from cosmic-neutron-induced reactions in the Earth's atmosphere, in various geologies, and in seawater. Initial results generated using the MCNP6 model and the suite of supporting MATLAB scripts indicate that the cosmic-neutron-induced 133Xe background activity concentrations at a depth of 1 m in a geology representative of the Earth's upper crust and a depth of 5 m in seawater are about 3.48 × 10-1 and 8.49 × 10-7 mBq m-3, respectively. (author)

  18. Characterization of corrosion products formed on steels in the first months of atmospheric exposure

    Directory of Open Access Journals (Sweden)

    Renato Altobelli Antunes

    2003-06-01

    Full Text Available The corrosion products of carbon steel and weathering steel exposed to three different types of atmospheres, at times ranging from one to three months, have been identified. The steels were exposed in an industrial site, an urban site (São Paulo City, Brazil, and a humid site. The effect of the steel type on the corrosion products formed in the early stages of atmospheric corrosion has been evaluated. The corrosion products formed at the various exposure locations were characterized by Raman microscopy, X-Ray diffraction (XRD and their morphology was observed by Scanning Electron Microscopy (SEM. Three regions of different colours (yellow, black and red have been identified over the steel coupons by Raman microscopy. Analysis carried out on each of these areas led to the characterization of the correspondent oxide/hydroxide phases. The main phases present were lepidocrocite (g-FeOOH and goethite (a-FeOOH. Small amounts of magnetite (Fe3O4 were also eventually encountered.

  19. Study of Ozone-Initiated Limonene Reaction Products by Low Temperature Plasma Ionization Mass Spectrometry

    Science.gov (United States)

    Nørgaard, Asger W.; Vibenholt, Anni; Benassi, Mario; Clausen, Per Axel; Wolkoff, Peder

    2013-07-01

    Limonene and its ozone-initiated reaction products were investigated in situ by low temperature plasma (LTP) ionization quadrupole time-of-flight (QTOF) mass spectrometry. Helium was used as discharge gas and the protruding plasma generated ~850 ppb ozone in front of the glass tube by reaction with the ambient oxygen. Limonene applied to filter paper was placed in front of the LTP afterglow and the MS inlet. Instantly, a wide range of reaction products appeared, ranging from m/ z 139 to ca. 1000 in the positive mode and m/ z 115 to ca. 600 in the negative mode. Key monomeric oxidation products including levulinic acid, 4-acetyl-1-methylcyclohexene, limonene oxide, 3-isopropenyl-6-oxo-heptanal, and the secondary ozonide of limonene could be identified by collision-induced dissociation. Oligomeric products ranged from the nonoxidized dimer of limonene (C20H30) and up to the hexamer with 10 oxygen atoms (C60H90O10). The use of LTP for in situ ozonolysis and ionization represents a new and versatile approach for the assessment of ozone-initiated terpene chemistry.

  20. Hexagonal boron nitride thin film thermal neutron detectors with high energy resolution of the reaction products

    International Nuclear Information System (INIS)

    Hexagonal boron nitride (h-BN) is highly promising for solid-state thermal neutron detector applications due to its many outstanding physical properties, especially its very large thermal neutron capture cross-section (~3840 barns for 10B), which is several orders of magnitude larger than those of most other isotopes. The focus of the present work is to carry out studies on h-BN thin film and detector properties to lay the foundation for the development of a direct-conversion solid-state thermal neutron detector with high sensitivity. The measured carrier mobility-lifetime (μτ) product of h-BN thin films grown on sapphire substrates is 2.83×10−7 cm2/V for electrons and holes, which is comparable to the value of about 10−7 cm2/V for GaN thin films grown on sapphire. Detectors based on h-BN thin films were fabricated and the nuclear reaction product pulse height spectra were measured. Under a bias of 20 V, very narrow individual peaks corresponding to the reaction product energies of α and Li particles as well as the sum peaks have been clearly resolved in the pulse height spectrum for the first time by a B-based direct-conversion semiconductor neutron detector. Our results indicate that h-BN thin film detectors possess unique advantages including small size, low weight, portability, low voltage operation and high energy resolution of specific reaction products

  1. Hexagonal boron nitride thin film thermal neutron detectors with high energy resolution of the reaction products

    Science.gov (United States)

    Doan, T. C.; Majety, S.; Grenadier, S.; Li, J.; Lin, J. Y.; Jiang, H. X.

    2015-05-01

    Hexagonal boron nitride (h-BN) is highly promising for solid-state thermal neutron detector applications due to its many outstanding physical properties, especially its very large thermal neutron capture cross-section (~3840 barns for 10B), which is several orders of magnitude larger than those of most other isotopes. The focus of the present work is to carry out studies on h-BN thin film and detector properties to lay the foundation for the development of a direct-conversion solid-state thermal neutron detector with high sensitivity. The measured carrier mobility-lifetime (μτ) product of h-BN thin films grown on sapphire substrates is 2.83×10-7 cm2/V for electrons and holes, which is comparable to the value of about 10-7 cm2/V for GaN thin films grown on sapphire. Detectors based on h-BN thin films were fabricated and the nuclear reaction product pulse height spectra were measured. Under a bias of 20 V, very narrow individual peaks corresponding to the reaction product energies of α and Li particles as well as the sum peaks have been clearly resolved in the pulse height spectrum for the first time by a B-based direct-conversion semiconductor neutron detector. Our results indicate that h-BN thin film detectors possess unique advantages including small size, low weight, portability, low voltage operation and high energy resolution of specific reaction products.

  2. Reactions of the OOH radical with guanine: Mechanisms of formation of 8-oxoguanine and other products

    Science.gov (United States)

    Kumar, Nagendra; Shukla, P. K.; Mishra, P. C.

    2010-09-01

    The mutagenic product 8-oxoguanine (8-oxoGua) is formed due to intermediacy of peroxyl (OOR) radicals in lipid peroxidation and protein oxidation-induced DNA damage. The mechanisms of these reactions are not yet understood properly. Therefore, in the present study, the mechanisms of formation of 8-oxoGua and other related products due to the reaction of the guanine base of DNA with the hydroperoxyl radical (OOH) were investigated theoretically employing the B3LYP and BHandHLYP hybrid functionals of density functional theory and the polarizable continuum model for solvation. It is found that the reaction of the OOH radical with guanine can occur following seven different mechanisms leading to the formation of various products including 8-oxoGua, its radicals, 5-hydroxy-8-oxoguanine and CO 2. The mechanism that yields 8-oxoGua as an intermediate and 5-hydroxy-8-oxoGua as the final product was found to be energetically most favorable.

  3. Markers of heterogeneous reaction products in α-pinene ozone secondary organic aerosol

    Science.gov (United States)

    Czoschke, Nadine M.; Jang, Myoseon

    A gas chromatograph iontrap mass spectrometer (GC-ITMS) was used to analyze the gas-and particle-phase products of α-pinene ozone oxidation in the presence of three different inorganic seed aerosols: sodium chloride, ammonium sulfate only, and ammonium sulfate with sulfuric acid. Products of α-pinene ozone oxidation common to the literature showed little difference in gas or particle-phase concentrations between seed types within the precision of the measurements even though significantly different aerosol yields were found between seed types. Small amounts of ring-opening products of four-membered cyclic oxygenates and markers of aldol condensation products were tentatively identified in the particle-phase for all seed types. These tentatively identified products are thought to be the result of acid-catalyzed heterogeneous reactions in the particle-phase or during sampling processes or analysis. The mechanisms for their formation are also proposed in this study.

  4. Theoretical investigation of the hydrogen shift reactions in peroxy radicals derived from the atmospheric decomposition of 3-methyl-3-buten-1-ol (MBO331)

    DEFF Research Database (Denmark)

    Knap, Hasse Christian; Jørgensen, Solvejg; Kjærgaard, Henrik Grum

    2015-01-01

    The hydroxy peroxy radical derived from the oxidation of 3-methyl-3-buten-1-ol (MBO331), can undergo four different hydrogen shift (H-shift) reactions. We have compared optimized geometries, barrier heights and reaction rate constants obtained with five different DFT functionals (BLYP, B3LYP, BHand......HLYP, wB97X-D and M06-2X) with the aug-cc-pVTZ basis set. We found that the single-point CCSD(T)-F12A/VDZ-F12 energies calculated at the different DFT geometries had very similar barrier heights. The wB97X-D, M06-2X and CCSD(T)-F12A/VDZ-F12 barrier heights are comparable. The atmospheric decomposition of...... the MBO331 peroxy radical was found to undergo a 1,5-CH H-shift reaction with a reaction rate constant of about 1 s-1....

  5. Product lambda-doublet ratios for the O(3P) + D2 reaction: A mechanistic imprint

    CERN Document Server

    Jambrina, P G; Aldegunde, J; Brouard, M; Aoiz, F J

    2016-01-01

    In the last decade, the development of theoretical methods have allowed chemists to reproduce and explain almost all of the experimental data associated with elementary atom plus diatom collisions. However, there are still a few examples where theory cannot account yet for experimental results. This is the case for the preferential population of one of the $\\Lambda$-doublet states produced by chemical reactions. In particular, recent measurements of the OD($^2\\Pi$) product of the O($^3$P) + D$_2$ reaction have shown a clear preference for the $\\Pi(A')$ $\\Lambda$-doublet states, in apparent contradiction with {\\em ab initio} calculations, which predict a larger reactivity on the $A"$ potential energy surface. Here we present a method to calculate the $\\Lambda$-doublet ratio when concurrent potential energy surfaces participate in the reaction. It accounts for the experimental $\\Lambda$-doublet populations via explicit consideration of the stereodynamics of the process. Furthermore, our results demonstrate that...

  6. FOBOS - a 4π-fragment spectrometer for heavy-ion reaction products

    International Nuclear Information System (INIS)

    The FOBOS detector presently under construction at Dubna is intended for heavy ion reaction studies in the bombarding energy range of 10...100 AMeV. It will consist of a 'gas-ball' of 30 position-sensitive avalanche counters and 30 axial ionization chambers behind them, a shell of 190 scintillation counters surrounding the gas ball and a forward phoswich array. All charged reaction products may be measured in a wide dynamic range and in a geometry covering a substantial part of 4π. Special developments were necessary concerning the mechanical construction, the detector design, the evacuation and gas supply and the electronics. Presently individual detector modules are being tested at the beam of the U-400 heavy ion cyclotron of the Laboratory of nuclear reactions. (orig.)

  7. Hydrogen production by radio frequency plasma stimulation in methane hydrate at atmospheric pressure

    OpenAIRE

    Putra, Andi Erwin Eka

    2013-01-01

    Methane hydrate, formed by injecting methane into 100 g of shaved ice at a pressure of 7 MPa and reactor temperature of 0 ??C, was decomposed by applying 27.12 MHz radio frequency plasma in order to produce hydrogen. The process involved the stimulation of plasma in the methane hydrate with a variable input power at atmospheric pressure. It was observed that production of CH4 is optimal at a slow rate of CH4 release from the methane hydrate, as analyzed by in light of the steam...

  8. Carbon Nanostructures Production by AC Arc Discharge Plasma Process at Atmospheric Pressure

    OpenAIRE

    Shenqiang Zhao; Ruoyu Hong; Zhi Luo; Haifeng Lu; Biao Yan

    2011-01-01

    Carbon nanostructures have received much attention for a wide range of applications. In this paper, we produced carbon nanostructures by decomposition of benzene using AC arc discharge plasma process at atmospheric pressure. Discharge was carried out at a voltage of 380 V, with a current of 6 A–20 A. The products were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), and Raman spectra. The results sho...

  9. Development of Level 3 (gridded) products for the Atmospheric Infrared Sounder (AIRS)

    Science.gov (United States)

    Granger, Stephanie L.; Leroy, Stephen S.; Manning, Evan M.; Fetzer, Eric J.; Oliphant, Robert B.; Braverman, Amy; Lee, Sung-Yung; Lambrigtsen, Bjom H.

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) sounding system is a suite of infrared and microwave instruments flown as part of NASA's Earth Observing System (EOS) onboard the Aqua platform. The AIRS dataset provides a daily, global view of Earth processes at a finer vertical resolution than ever before. However, analysis of the AIRS data is a daunting task given the sheer volume and complexity of the data. The volume of data produced by the EOS project is unprecedented; the AIRS project alone will produce many terabytes of data over the lifetime of the mission. This paper describes development of AIRS Level 3 data products that will help to alleviate problems of access and usability.

  10. Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment.

    Science.gov (United States)

    Norby, Richard J; Ledford, Joanne; Reilly, Carolyn D; Miller, Nicole E; O'Neill, Elizabeth G

    2004-06-29

    Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO(2) enrichment experiment. Annual production of fine roots was more than doubled in plots with 550 ppm CO(2) compared with plots in ambient air. This response was the primary component of the sustained 22% increase in net primary productivity. Annual fine-root mortality matched annual production, and the mean residence time of roots was not altered by elevated CO(2), but peak fine-root standing crop in midsummer was significantly higher in CO(2)-enriched plots, especially deeper in the soil profile. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood reduces the possibility of long-term enhancement by elevated CO(2) of carbon sequestration in biomass. However, sequestration of some of the fine-root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine-root system. Root-system dynamics can explain differences among ecosystems in their response to elevated atmospheric CO(2); hence, accurate assessments of carbon flux and storage in forests in a globally changing atmosphere must account for this unseen and difficult-to-measure component. PMID:15210962

  11. Characterizations of self-combustion reactions (SCR) for the production of nanomaterials used as advanced cathodes in Li-ion batteries

    International Nuclear Information System (INIS)

    In this work, self-combustion reactions (SCR) for the preparation of important cathode materials for rechargeable Li-ion batteries were investigated by thermal analytical tools (DSC, ARC, TGA), electron microscopy, XRD, various spectroscopies (MS, Raman, FTIR) and elemental analysis by ICP. The systems studied include solutions containing metal nitrates at the right stoichiometry and sucrose as a fuel, for the preparation of LiMn0.5Ni0.5O2 (layered), LiMn1.5Ni0.5O4 (spinel), LiMn0.33Ni0.33Co0.33O2 (layered), and LiMn0.4Ni0.4Co0.2O2 (layered). Similar products, which do not depend on the atmosphere of the processes (air or inert) were obtained by spontaneous SCR and the gradual heating of the same solutions by DSC, ARC, and TGA. The reactions involve the partial caramelization of sucrose, complicated by red-ox reactions with the nitrates that form solid products, whose organic part is finally decomposed around 400 oC. The presence of cobalt ions has a stabilizing effect, which is expressed by the low dissolution rates of Li ions from the solid products thus formed, into aqueous solutions. The reaction mechanisms are discussed herein.

  12. Relative rate coefficient measurements of OH radical reactions with (Z)-2-hexen-1-ol and (E)-3-hexen-1-ol under simulated atmospheric conditions

    Science.gov (United States)

    Peirone, Silvina A.; Barrera, Javier A.; Taccone, Raúl A.; Cometto, Pablo M.; Lane, Silvia I.

    2014-03-01

    The relative rate technique was used to determine the rate coefficients of the reactions of OH radicals with (Z)-2-hexen-1-ol (k1), and (E)-3-hexen-1-ol (k2), at (296 ± 2) K and (750 ± 10) Torr of N2 or pure air. The reactions were investigated using a 200 L Teflon reaction chamber and a gas chromatograph coupled with flame-ionization detection. The following rate coefficients were derived, in units of cm3 mol-1 s-1: k1 = (1.1 ± 0.4) × 10-10 and k2 = (0.8 ± 0.1) × 10-10. This is the first experimental determination of k1 and k2. A comparison between the experimental rate coefficients (kexp) and the calculated rate coefficients using the structure-activity relationship (SAR) method (kSAR), for the reaction of different unsaturated alcohols with OH radicals is presented. The atmospheric lifetimes of the studied alcohols were estimated considering the rate coefficients of their reactions with OH and NO3 radicals. The radiative efficiencies (REs) were obtained from the infrared spectra of the two hexenols and the global warming potentials (GWPs) were then estimated. Atmospheric implications of the alcohols emission are briefly discussed.

  13. Zeolite Membrane Reactor for Water Gas Shift Reaction for Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jerry Y.S. [Arizona State Univ., Mesa, AZ (United States)

    2013-01-29

    Gasification of biomass or heavy feedstock to produce hydrogen fuel gas using current technology is costly and energy-intensive. The technology includes water gas shift reaction in two or more reactor stages with inter-cooling to maximize conversion for a given catalyst volume. This project is focused on developing a membrane reactor for efficient conversion of water gas shift reaction to produce a hydrogen stream as a fuel and a carbon dioxide stream suitable for sequestration. The project was focused on synthesizing stable, hydrogen perm-selective MFI zeolite membranes for high temperature hydrogen separation; fabricating tubular MFI zeolite membrane reactor and stable water gas shift catalyst for membrane reactor applications, and identifying experimental conditions for water gas shift reaction in the zeolite membrane reactor that will produce a high purity hydrogen stream. The project has improved understanding of zeolite membrane synthesis, high temperature gas diffusion and separation mechanisms for zeolite membranes, synthesis and properties of sulfur resistant catalysts, fabrication and structure optimization of membrane supports, and fundamentals of coupling reaction with separation in zeolite membrane reactor for water gas shift reaction. Through the fundamental study, the research teams have developed MFI zeolite membranes with good perm-selectivity for hydrogen over carbon dioxide, carbon monoxide and water vapor, and high stability for operation in syngas mixture containing 500 part per million hydrogen sulfide at high temperatures around 500°C. The research teams also developed a sulfur resistant catalyst for water gas shift reaction. Modeling and experimental studies on the zeolite membrane reactor for water gas shift reaction have demonstrated the effective use of the zeolite membrane reactor for production of high purity hydrogen stream.

  14. Multi-reaction-channel fitting calculations in a coupled-channel model: Photoinduced strangeness production

    Indian Academy of Sciences (India)

    O Scholten; A Usov

    2010-08-01

    To describe photo- and meson-induced reactions on the nucleon, one is faced with a rather extensive coupled-channel problem. Ignoring the effects of channel coupling, as one would do in describing a certain reaction at the tree level, invariably creates a large inconsistency between the different reactions that are described. In addition, the imaginary parts of the amplitude, which are related through the optical theorem, to total cross-sections, are directly reflected in certain polarization observables. Performing a full coupled-channel calculation thus offers the possibility to implement the maximum number of constraints. The drawback one is faced with is to arrive at a simultaneous fit of a large number of reaction channels. While some of the parameters are common to many reactions, one is still faced with the challenge to optimize a large number of parameters in a highly non-linear calculation. Here we show that such an approach is possible and present some results for photoinduced strangeness production.

  15. Temporally resolved ozone distribution of a time modulated RF atmospheric pressure argon plasma jet: flow, chemical reaction, and transient vortex

    Science.gov (United States)

    Zhang, S.; Sobota, A.; van Veldhuizen, E. M.; Bruggeman, P. J.

    2015-08-01

    The ozone density distribution in the effluent of a time modulated RF atmospheric pressure plasma jet (APPJ) is investigated by time and spatially resolved by UV absorption spectroscopy. The plasma jet is operated with an averaged dissipated power of 6.5 W and gas flow rate 2 slm argon  +2% O2. The modulation frequency of the RF power is 50 Hz with a duty cycle of 50%. To investigate the production and destruction mechanism of ozone in the plasma effluent, the atomic oxygen and gas temperature is also obtained by TALIF and Rayleigh scattering, respectively. A temporal increase in ozone density is observed close to the quartz tube exit when the plasma is switched off due to the decrease in O density and gas temperature. Ozone absorption at different axial positions indicates that the ozone distribution is dominated by the convection induced by the gas flow and allows estimating the on-axis local gas velocity in the jet effluent. Transient vortex structures occurring during the switch on and off of the RF power also significantly affect the ozone density in the far effluent.

  16. Atmospheric chemistry of CH3CHF2 (R-152a): mechanism of the CH3CF2O2+HO2 reaction

    DEFF Research Database (Denmark)

    Hashikawa, Y; Kawasaki, M; Andersen, Mads Peter Sulbæk;

    2004-01-01

    FTIR smog chamber techniques have been used to investigate the mechanism of the reaction of CH3CF2O2 with HO2 radicals in 100-700 Torr of synthetic air at 296 K. The reaction gives CH3CF2OOH and COF2 in molar yields of 0.53 +/- 0.05 and 0.47 +/- 0.05, respectively. Results are discussed with...... respect to the atmospheric chemistry of peroxy radicals and the environmental impact of R-152a. (C) 2004 Elsevier B.V. All rights reserved....

  17. One-Pot Synthesis of N-(α-Peroxy)Indole/Carbazole via Chemoselective Three-Component Condensation Reaction in Open Atmosphere

    KAUST Repository

    Wang, Xinbo

    2015-11-06

    A facile one-pot synthesis of N-(α-peroxy)indole and N-(α-peroxy)carbazole has been developed using metal-free, organo-acid-catalyzed three-component condensation reactions of indole/carbazole, aldehyde, and peroxide. Based on the reaction discovered, a new synthetic proposal for Fumitremorgin A and Verruculogen is introduced. Such a protocol could be easily handled and scaled up in an open atmosphere with a wide substrate scope, enabling the construction of a new molecule library.

  18. Measurement of fragment production cross-section on nucleon-induced reaction

    International Nuclear Information System (INIS)

    We introduce our activities on measurements of fragment which are secondary particles heavier than alpha-particles produced by nucleon-induced reaction and have been recognized to be a cause of serious problem to semiconductor devices and human in a space environment by using a Bragg curve spectrometer (BCS) and energy-time-of-flight method (E-TOF), together with the activities in other facilities. For these studies and estimation, it is important to know the fragment production yield including the energy and angular distribution (double-differential cross-section (DDX) data) of fragments emission. We have resulted in success to obtain light fragments on proton- and neutron-induced reactions by using a BCS developed for neutron specially and E-TOF method. Double-differential fragment production cross-sections obtained will be applied for the analysis of SEU and dose contributions. (author)

  19. Sodium aerosol release rate and nonvolatile fission product retention factor during a sodium-concrete reaction

    International Nuclear Information System (INIS)

    This paper reports on a series of tests conducted to study the mechanical release behavior of sodium aerosols containing nonvolatile fission products during a sodium-concrete reaction in which release behavior due to hydrodynamic breakup of the hydrogen bubble is predominant at the sodium pool surface. In the tests, nonradioactive materials, namely, strontium oxide, europium oxide, and ruthenium particles, whose sizes range from a few microns to several tens of microns, are used as nonvolatile fission product stimulants. The following results are obtained: The sodium aerosol release rate during the sodium-concrete reaction is larger than that of natural evaporation. The difference, however, becomes smaller with increasing sodium temperature: nearly ten times smaller at 400 degrees C and three times at 700 degrees C. The retention factors for the nonvolatile materials in the sodium pool increase to the range of 0.5 to 104 with an increase in the sodium temperature from 400 to 700 degrees C

  20. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with aliphatic... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  1. 40 CFR 721.5560 - Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz[c...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with... Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6... identified as formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with...

  2. Identification of aminoglycoside-acetylating enzymes by high-pressure liquid chromatographic determination of their reaction products.

    OpenAIRE

    Lovering, A M; White, L. O.; Reeves, D S

    1984-01-01

    A method to identify the aminoglycoside-acetyltransferase (AAC) enzymes AAC(3), AAC(2') and AAC(6') by high-pressure liquid chromatographic characterization of their products of reaction with tobramycin or sisomicin is described. Conditions are given for the chromatography of kanamycin A, netilmicin, neomycin, and apramycin, and their products of reaction, if any, with the three AAC enzymes are listed.

  3. Activation cross sections of α-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: Production of 178W/178mTa generator

    International Nuclear Information System (INIS)

    In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of 178mTa through natHf(α,xn)178W–178mTa nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions natHf(α,x)179,177,176,175W, 183,182,178g,177,176,175Ta, 179m,177m,175Hf were also assessed. Stacked foil irradiation technique and γ-ray spectrometry were used. New experimental cross section data for the natTa(d,xn)178W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and (3He,x)) production routes for 178W. - Highlights: • α-Particle induced reactions on natural Hf up to 40 MeV by stacked foil technique. • Deuteron induced reactions on natural Ta up to 50 MeV by stacked foil technique. • Comparison of experimental results with the ALICE, EMPIRE and TALYS codes. • Calculation and comparison of thick target integral yields. • Comparison of the production routes of 178W

  4. Enhancement of atmospheric H2SO4/H2O nucleation: organic oxidation products versus amines

    Directory of Open Access Journals (Sweden)

    T. Berndt

    2013-06-01

    Full Text Available Atmospheric H2SO4/H2O nucleation influencing effects have been studied in the flow tube IfT-LFT (Institute for Tropospheric Research – Laminar Flow Tube at 293 ± 0.5 K and a pressure of 1 bar using synthetic air as the carrier gas. The presence of a possible background amine concentration in the order of 107–108 molecule cm−3 throughout the experiments has to be taken into account. In a first set of investigations, ozonolysis of olefins (tetramethylethylene, 1-methyl-cyclohexene, α-pinene and limonene for close to atmospheric concentrations, served as the source of OH radicals and possibly other oxidants initiating H2SO4 formation starting from SO2. The oxidant generation is inevitably associated with the formation of a series of organic oxidation products arising from the parent olefins. These products (first generation mainly showed no clear effect on the number of nucleated particles within a wide range of experimental conditions for H2SO4 concentrations higher than ~107 molecule cm−3. A comparison of the results of two different particle counters (50% cut-off size: about 1.5 nm or 2.5–3 nm suggested that the early growth process of the nucleated particles was not significantly influenced by the organic oxidation products. An additional, H2SO4-independent process of particle (nano-CN formation was observed in the case of α-pinene and limonene ozonolysis for H2SO4 concentrations smaller than ~10 7 molecule cm−3. Furthermore, the findings confirm the existence of an additional oxidant for SO2 beside OH radicals, very likely stabilized Criegee Intermediate (sCI. In the case of the ozonolysis of tetramethylethylene, the H2SO4 measurements in the absence and presence of an OH radical scavenger were well described by modelling using recently obtained kinetic data for the sCI reactivity in this system. A second set of experiments has been performed in the presence of added amines (trimethylamine, dimethylamine, aniline and pyridine in

  5. Light particle production in 12C induced reactions at Cern SC Energies

    International Nuclear Information System (INIS)

    The results from the first generation of experiments at the CERN synchrocyclotron with 30A MeV - 85A MeV 12C beams are beginning to manifest the pattern of heavy ion reactions in the region between the binary low energy side and the 'chaotic' high energy side. Results from experiments on the production of p, d, and pi at these energies are presented. (Author)

  6. Simple method for production of internal control DNA for Mycobacterium tuberculosis polymerase chain reaction assays.

    OpenAIRE

    Dewit, D.; Wootton, M.; Allan, B; Steyn, L

    1993-01-01

    A simple method for the production of internal control DNA for two well-established Mycobacterium tuberculosis polymerase chain reaction assays is described. The internal controls were produced from Mycobacterium kansasii DNA with the same primers but at a lower annealing temperature than that used in the standard assays. In both assays, therefore, the internal control DNA has the same primer-binding sequences at the target DNA. One-microgram quantities of internal control DNA which was not c...

  7. Microwave effects in heterogeneous catalysis: Application to gas-solid reactions for hydrogen production

    OpenAIRE

    Durka, T.

    2013-01-01

    Due to the quest for more efficient production processes both from the energy and selectivity point of view, microwave irradiation has attracted significant scientific attention over the last three decades, as an alternative means of chemical activation. Over this period, striking process benefits, such as higher conversions and selectivities and/or a shorter reaction times, compared to the respective conventionally heated processes have been reported. The aim of this work is to investigate t...

  8. Contribution of Phenolics and Maillard Reaction Products to the Antioxidant Capacity of Coffee Brews

    OpenAIRE

    Ludwig, I.A. (Iziar A.); Cid, C.; Peña, M. P.

    2015-01-01

    Coffee is one of the most consumed beverages in the world and a rich source of antioxidants. The amounts of these antioxidants are influenced by several technological factors. Besides, antioxidants identified in coffee (chlorogenic acids, volatile and non-volatile Maillard reaction products) may contribute to the overall antioxidant capacity in different proportions. Therefore the aim of this research was to evaluate the actual contribution to the overall antioxidant capacity of coffee brews ...

  9. Neutral products from cation-molecule reactions in the gas phase

    International Nuclear Information System (INIS)

    The use of neutral product analysis for examining ionic reaction pathways from electron impact is described. This approach merges techniques of mass spectrometry with those of radiation chemistry. Comparisons are made between experimental results and predictions based on density-of-states arguments using RRKM microscopic rate coefficients. The importance of examining isomer distributions is stressed with special attention given to the question of the mechanism of bimolecular proton transfer in the gas phase. (author)

  10. Product-form stationary distributions for deficiency zero chemical reaction networks

    OpenAIRE

    Anderson, David F.; Craciun, Gheorghe; Kurtz, Thomas G.

    2008-01-01

    We consider stochastically modeled chemical reaction systems with mass-action kinetics and prove that a product-form stationary distribution exists for each closed, irreducible subset of the state space if an analogous deterministically modeled system with mass-action kinetics admits a complex balanced equilibrium. Feinberg's deficiency zero theorem then implies that such a distribution exists so long as the corresponding chemical network is weakly reversible and has a deficiency of zero. The...

  11. Measurement of reaction cross sections of fission products induced by DT neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Daisuke; Murata, Isao; Takahashi, Akito [Osaka Univ., Suita (Japan)

    1998-03-01

    With the view of future application of fusion reactor to incineration of fission products, we have measured the {sup 129}I(n,2n){sup 128}I reaction cross section by DT neutrons with the activation method. The measured cross section was compared with the evaluated nuclear data of JENDL-3.2. From the result, it was confirmed that the evaluation overestimated the cross section by about 20-40%. (author)

  12. An Ionic Liquid Reaction and Separation Process for Production of Hydroxymethylfurfural from Sugars

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Zheng, Feng; Li, Joanne; Cooper, Alan R.

    2014-01-01

    There has been world-wide interest to making plastics out of renewable biomass feedstock for recent years. Hydroxymethylfurfural (HMF) is viewed as an attractive alternate to terephthalic acid (TPA) for production of polyesters (PET) and polyamides. Conversion of sugars into HMF has been studied in numerous publications. In this work, a complete ionic liquid reaction and separation process is presented for nearly stoichiometric conversion of fructose into HMF. Different adsorbent materials are evaluated and silicalite material is demonstrated effective for isolation of 99% pure HMF from actual ionic liquid reaction mixtures and for recovery of the un-converted sugars and reaction intermediate along with the ionic liquid. Membrane-coated silicalite particles are prepared and studied for a practical adsorption process operated at low pressure drops but with separation performances comparable or better than the powder material. Complete conversion of fresh fructose feed into HMF in the recycled ionic liquid is shown under suitable reaction conditions. Stability of HMF product is characterized. A simplified process flow diagram is proposed based on these research results, and the key equipment such as reactor and adsorbent bed is sized for a plant of 200,000 ton/year of fructose processing capacity. The proposed HMF production process is much simpler than the current paraxylene (PX) manufacturing process from petroleum oil, which suggests substantial reduction to the capital cost and energy consumption be possible. At the equivalent value to PX on the molar basis, there can be a large gross margin for HMF production from fructose and/or sugars.

  13. Monitoring variations of dimethyl sulfide and dimethylsulfoniopropionate in seawater and the atmosphere based on sequential vapor generation and ion molecule reaction mass spectrometry.

    Science.gov (United States)

    Iyadomi, Satoshi; Ezoe, Kentaro; Ohira, Shin-Ichi; Toda, Kei

    2016-04-20

    To monitor the fluctuations of dimethyl sulfur compounds at the seawater/atmosphere interface, an automated system was developed based on sequential injection analysis coupled with vapor generation-ion molecule reaction mass spectrometry (SIA-VG-IMRMS). Using this analytical system, dissolved dimethyl sulfide (DMSaq) and dimethylsulfoniopropionate (DMSP), a precursor to DMS in seawater, were monitored together sequentially with atmospheric dimethyl sulfide (DMSg). A shift from the equilibrium point between DMSaq and DMSg results in the emission of DMS to the atmosphere. Atmospheric DMS emitted from seawater plays an important role as a source of cloud condensation nuclei, which influences the oceanic climate. Water samples were taken periodically and dissolved DMSaq was vaporized for analysis by IMRMS. After that, DMSP was hydrolyzed to DMS and acrylic acid, and analyzed in the same manner as DMSaq. The vaporization behavior and hydrolysis of DMSP to DMS were investigated to optimize these conditions. Frequent (every 30 min) determination of the three components, DMSaq/DMSP (nanomolar) and DMSg (ppbv), was carried out by SIA-VG-IMRMS. Field analysis of the dimethyl sulfur compounds was undertaken at a coastal station, which succeeded in showing detailed variations of the compounds in a natural setting. Observed concentrations of the dimethyl sulfur compounds both in the atmosphere and seawater largely changed with time and similar variations were repeatedly observed over several days, suggesting diurnal variations in the DMS flux at the seawater/atmosphere interface. PMID:27046734

  14. Radon and its short-lived daughter products in the lower atmosphere

    International Nuclear Information System (INIS)

    The variations of vertical and temporal distributions of natural radioactivity with geographical location in the lower atmospheric layers are shown. The content of radon and its short lived daughters products are measured. Radon content is measured continually with a new apparatus, the sensibility of which is 0,2.10-11 Ci m-3 i.e. the fiftieth of the mean concentration near the soil, this apparatus allowed us to show that radioactive equilibrium between radon and its daughter products is realised when the atmosphere is stable. Air observations between 0 and 100 meters above the ground point out that radon and its decay products are valuable tracers to mark the stability of the atmosphere. Under very stable nighttime conditions the radon accumulates in the former 30 meters of the air layer, at sunrise it ascends and at 9 o'clock attains 100 meters high. The removal rate of the air in the lower atmosphere is computed from the movement of this radon mass, it is equal to 90 per cent for a summer day. We have show that this radon comes from the soil in which it diffuses by brownian motion the intensity of which varies with the water content of the soil, its value for June 1958 is 6,10-17 Ci cm-2s-1 and for January 1959 0.2,10-17 Ci cm-2 s-1. During the year 1958-1959 general mean of flux for the sedimentary soil studied is equal to 3. 8 ± 1.3, 10-17 Ci cm-2 s-1 it is identical to the world wide mean computed by H. Israel. In a hilly site in the Morvan, air movements are well marked by this radioactivity. We observed from one hand downslope and up-slope breezes having, respectively, speeds of 0.2 m s-1 and 0.7 m s-1 and from the other hand by night, in the valley and with a light wind favours the stagnation of the air near the ground, a strong increase of the radioactivity which is proportional to the one of the granitic rocks of the region. The radon flux of this soil is 74,10-17 Ci cm-2s-1 and the radioactivity of the air can attain 1.5,10-8 Ci m-3 that is five times

  15. Episodic inputs of atmospheric nitrogen to the Sargasso Sea: Contributions to new production and phytoplankton blooms

    Science.gov (United States)

    Michaels, Anthony F.; Siegel, David A.; Johnson, Rodney J.; Knap, Anthony H.; Galloway, James N.

    1993-06-01

    Atmospheric wet deposition rates of nitrate and ammonia on Bermuda collected in the Atmosphere Ocean Chemistry Experiment (AEROCE) are compared with the synoptic measurements of carbon and nitrogen cycling from the U.S. Joint Global Ocean Flux Study (JGOFS) Bermuda Atlantic Time Series Study (BATS) station, 75 km southeast of Bermuda. Measurable deposition events were found on 23.8% of the days between October 1, 1988 and June 30, 1991. However, only a few of these events significantly contributed to the standing stocks of nitrogen and phytoplankton or rates of primary production. For 1.7% of the days each year, the atmospheric nitrogen deposition would have equaled the sinking particulate nitrogen flux as estimated by sediment traps. For only 0.2% of the time, would adequate nitrogen be deposited to a 20 m mixed layer to change the surface concentrations of particulate organic nitrogen by 10%. The results are dramatically different if all of the deposition remains confined to the upper l m of the water column enabling intense, surface phytoplankton blooms to occur. The occurrence of these near-surface blooms may be an important signal in the interpretation of satellite ocean color imagery, particularly when the satellite data are used to infer whole water-column phytoplankton stocks or productivity. Numerical simulations of the evolution of the near-surface mixed layer after a rainfall event indicate that low salinity surface waters would be mixed to the upper 10 m or so within 2-4 hours, except for wind speeds less than approximately 5m s-1. Thus, wet deposition induced surface algae blooms should only be observed under relatively calm meteorological conditions. In summary, wet deposition of nitrogen is a relatively unimportant process in affecting upper ocean nitrogen cycling for the Sargasso Sea off Bermuda, although in oceans with lower productivity and areas where deposition may increase with future industrial development, episodic deposition events may

  16. Flame made ceria supported noble metal catalysts for efficient H2 production via the water gas shift reaction

    Science.gov (United States)

    Cavusoglu, G.; Lichtenberg, H.; Gaur, A.; Goldbach, A.; Grunwaldt, J.-D.

    2016-05-01

    Rh/ceria catalysts were synthesized by flame spray pyrolysis for high temperature water gas shift (WGS) reactions. These catalysts show a high specific surface area due to a high degree of nanocrystallinity. X-ray absorption spectroscopy (XAS) unraveled the formation of small Rh particles under WGS reaction conditions. The catalytic activity was examined at atmospheric pressure by measuring CO conversion as a function of temperature. Some methane formation was observed above 310°C.

  17. Inhibition of T-2 toxin production on high-moisture corn kernels by modified atmospheres

    International Nuclear Information System (INIS)

    The fungus Fusarium sporotrichioides, capable of producing T-2 toxin (T-2), was grown on irradiated corn kernels remoistened to 22% and kept in atmospheres of different CO2-O2 combinations. The production of T-2 was totally inhibited under 60% CO2-20% O2, whereas only trace amounts were detected when the gas combination was 40% CO2-5% O2. Under all other combinations tested, the amount of T-2 produced was reduced by 25 to 50% as compared with the control. Fungal growth was not inhibited by any of the gas mixtures examined, and the growth rate (measured by direct plating, dilution method, and CO2 production) was almost identical to that in grains kept under air. It is concluded that although F. sporotrichioides is tolerant to high CO2 levels, T-2 formation on corn can be inhibited by CO2 concentrations less than that required to inhibit fungal growth

  18. Relative importance of nitrate and sulfate aerosol production mechanisms in urban atmospheres

    International Nuclear Information System (INIS)

    The relative importance of the various sulfate and nitrate aerosol production mechanisms is calculated for different atmospheric conditions. The calculation scheme used to determine the rates of nitrate and sulfate production, based on the concept that vapor transfer to the aerosols and nitrate and sulfate formation within the aerosols are coupled kinetic processes, considers sulfate formation by ozone and hydrogen peroxide oxidation and catalytic oxidation in the presence of soot, iron and manganese of sulfite solutions and sulfuric acid condensation and nitrate formation by the liquid-phase oxidation of dissolved nitrogen oxides for different initial gas concentrations and particle compositions and sizes. It is found that sulfate production is higher under daytime conditions, primarily proceeding by mechanisms involving sulfuric acid and hydrogen peroxide, while at night oxidation processes on the surface of the aerosol film are more important. Nitrate tends to decrease nighttime sulfate production due to an increase in aerosol acidity and nitrate production is found to be higher under nighttime conditions and in the winter

  19. Crystal structure of an EAL domain in complex with reaction product 5'-pGpG.

    Directory of Open Access Journals (Sweden)

    Julien Robert-Paganin

    Full Text Available FimX is a large multidomain protein containing an EAL domain and involved in twitching motility in Pseudomonas aeruginosa. We present here two crystallographic structures of the EAL domain of FimX (residues 438-686: one of the apo form and the other of a complex with 5'-pGpG, the reaction product of the hydrolysis of c-di-GMP. In both crystal forms, the EAL domains form a dimer delimiting a large cavity encompassing the catalytic pockets. The ligand is trapped in this cavity by its sugar phosphate moiety. We confirmed by NMR that the guanine bases are not involved in the interaction in solution. We solved here the first structure of an EAL domain bound to the reaction product 5'-pGpG. Though isolated FimX EAL domain has a very low catalytic activity, which would not be significant compared to other catalytic EAL domains, the structure with the product of the reaction can provides some hints in the mechanism of hydrolysis of the c-di-GMP by EAL domains.

  20. Hypernucleus Production by $A(p,pK^+)_{\\Lambda}B$ Reactions

    CERN Document Server

    Jing, Hantao; Chiang, Huanching

    2008-01-01

    The $\\Lambda$-hypernucleus production by $A(p, pK^+)_{\\Lambda}B$ reactions is investigated within the framework of the distorted wave impulse approximation(DWIA). The amplitude for the elementary process is evaluated in a fully covariant two-nucleon model based on the effective Lagrangian. The reaction cross sections for $\\Lambda$-hypernucleus productions on $^6Li$, $^{12}C$ and $^{16}O$ targets are calculated. It is found that the distortion effects tend to reduce the cross sections by a factor of 3$\\sim$10. Various differential cross sections (DCS) and double differential cross sections (DDCS) are presented. It is shown that for the $s_{\\Lambda}-$wave hypernucleus production, the DCS is decreased with increasing nuclear mass, and the DCS for the $p_{\\Lambda}-$wave hypernucleus production is normally higher than that for the $s_{\\Lambda}-$wave hypernucleus production. As a reference, the DDCS with respect to the momenta of the outgoing proton and kaon is also demonstrated. Finally, the missing mass spectra o...

  1. Product polarization distribution: Stereodynamics of the reaction of atom H and radical NH

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The product angular momentum polarization of the reaction of H+NH is calculated via the quasiclassical trajectory method(QCT)based on the extended London-Eyring-Polanyi-Sato(LEPS)potential energy surface(PES)at a collision energy of 5.1 kcal/mol.The calculated results of the vector correlations are denoted by using the angular distribution functions.The polarization-dependent differential cross sections(PDDCSs)demonstrate that the rotational angular momentum of the product H2 is aligned and oriented along the direction perpendicular to the scattering plane.Vector correlation shows that the angular momentum of the product H2 is aligned in the plane perpendicular to the velocity vector.It suggests that the reaction proceeds preferentially when the reactant velocity vector lies in a plane containing all three atoms.The orientation and alignment of the product angular momentum affects the scattering direction of the product molecules.The polarization-dependent differential cross sections(PDDCSs)reveal that scattering is predominantly in the backward hemisphere.

  2. Effects of patchy ocean fertilization on atmospheric carbon dioxide and biological production

    Science.gov (United States)

    Gnanadesikan, Anand; Sarmiento, Jorge L.; Slater, Richard D.

    2003-06-01

    Increasing oceanic productivity by fertilizing nutrient-rich regions with iron has been proposed as a mechanism to offset anthropogenic emissions of carbon dioxide. Earlier studies examined the impact of large-scale fertilization of vast reaches of the ocean for long periods of time. We use an ocean general circulation model to consider more realistic scenarios involving fertilizing small regions (a few hundred kilometers on a side) for limited periods of time (of order 1 month). A century after such a fertilization event, the reduction of atmospheric carbon dioxide is between 2% and 44% of the initial pulse of organic carbon export to the abyssal ocean. The fraction depends on how rapidly the surface nutrient and carbon fields recover from the fertilization event. The modeled recovery is very sensitive to the representation of biological productivity and remineralization. Direct verification of the uptake would be nearly impossible since changes in the air-sea flux due to fertilization would be much smaller than those resulting from natural spatial variability. Because of the sensitivity of the uptake to the long-term fate of the iron and organic matter, indirect verification by measurement of the organic matter flux would require high vertical resolution and long-term monitoring. Finally, the downward displacement of the nutrient profile resulting from an iron-induced productivity spurt may paradoxically lead to a long-term reduction in biological productivity. In the worst-case scenario, removing 1 ton of carbon from the atmosphere for a century is associated with a 30-ton reduction in biological export of carbon.

  3. Numerical study of the effect of water content on OH production in a pulsed-dc atmospheric pressure helium-air plasma jet

    Science.gov (United States)

    Mu-Yang, Qian; Cong-Ying, Yang; Zhen-dong, Wang; Xiao-Chang, Chen; San-Qiu, Liu; De-Zhen, Wang

    2016-01-01

    A numerical study of the effect of water content on OH production in a pulsed-dc atmospheric pressure helium-air plasma jet is presented. The generation and loss mechanisms of the OH radicals in a positive half-cycle of the applied voltage are studied and discussed. It is found that the peak OH density increases with water content in air (varying from 0% to 1%) and reaches 6.3×1018 m-3 when the water content is 1%. Besides, as the water content increases from 0.01% to 1%, the space-averaged reaction rate of three-body recombination increases dramatically and is comparable to those of main OH generation reactions. Project supported by the National Natural Science Foundation of China (Grant No. 11465013), the Natural Science Foundation of Jiangxi Province, China (Grant No. 20151BAB212012), and the International Science and Technology Cooperation Program of China (Grant No. 2015DFA61800).

  4. Rapid analysis of the skin irritant p-phenylenediamine (PPD) in henna products using atmospheric solids analysis probe mass spectrometry.

    Science.gov (United States)

    Chen, Weiyang; Nkosi, Thobile A N; Combrinck, Sandra; Viljoen, Alvaro M; Cartwright-Jones, Catherine

    2016-09-01

    Henna (Lawsonia inermis) is applied to stain keratin, present in hair, skin and fingernails, a red-orange or rust colour. Producers of temporary tattoos mix the aromatic amine compound, para-phenylenediamine (PPD) into natural henna to create 'black henna' that rapidly stains the skin black. However, PPD may cause severe delayed hypersensitivity reactions following skin contact. This study proposes a rapid direct-analysis method to detect and identify PPD using an atmospheric solids analysis probe (ASAP) coupled to a Q-ToF mass spectrometer (MS). Since laborious, multistep methods of analysis to determine PPD are undesirable, due to the instability of the compound in solution, a screening method involving no sample preparation steps was developed. Experiments were carried out to optimise the corona current, sample cone voltage, source temperature, and desolvation gas temperature to determine ideal ASAP-Q-ToF-MS analysing conditions. Eleven of the 109 henna samples, originating from various countries, tested positive for PPD when henna products were screened using ASAP-MS, without any form of sample preparation other than grinding. Ultra-performance liquid chromatography electrospray ionisation-mass spectrometry (UPLC-Q-ToF-MS) was subsequently used to confirm the results from ASAP and to determine the concentrations of PPD in henna products. The allergen was detected in the same eleven samples, with concentrations ranging from 0.05-4.21% (w/w). It can be concluded that the sensitivity of the ASAP-MS technique is sufficient (limit of detection=0.025% w/w) to allow screening of henna samples for the presence of PPD. This relatively new technique can be applied to commercial products without extraction, sample treatment or chromatographic separation. PMID:27243826

  5. Large-Scale Refolding and Enzyme Reaction of Human Preproinsulin for Production of Human Insulin.

    Science.gov (United States)

    Kim, Chang-Kyu; Lee, Seung-Bae; Son, Young-Jin

    2015-10-28

    Human insulin is composed of 21 amino acids of an A-chain and 30 amino acids of a B-chain. This is the protein hormone that has the role of blood sugar control. When the recombinant human proinsulin is expressed in Escherichia coli, a serious problem is the formation of an inclusion body. Therefore, the inclusion body must be denatured and refolded under chaotropic agents and suitable reductants. In this study, H27R-proinsulin was refolded from the denatured form with β-mercaptoethanol and urea. The refolding reaction was completed after 15 h at 15°C, whereas the reaction at 25°C was faster than that at 15°C. The refolding yield at 15°C was 17% higher than that at 25°C. The refolding reaction could be carried out at a high protein concentration (2 g/l) using direct refolding without sulfonation. The most economical and optimal refolding condition for human preproinsulin was 1.5 g/l protein, 10 mM glycine buffer containing 0.6 M urea, pH 10.6, and 0.3 mM β-mercaptoethanol at 15°C for 16 h. The maximum refolding yield was 74.8% at 15°C with 1.5 g/l protein. Moreover, the refolded preproinsulin could be converted into normal mature insulin with two enzymes. The average amount of human insulin was 138.2 g from 200 L of fermentation broth after enzyme reaction with H27R-proinsulin. The direct refolding process for H27R-proinsulin was successfully set up without sulfonation. The step yields for refolding and enzyme reaction were comparatively high. Therefore, our refolding process for production of recombinant insulin may be beneficial to the large-scale production of other biologically active proteins. PMID:26139616

  6. Gas-Solid Reaction Route toward the Production of Intermetallics from Their Corresponding Oxide Mixtures

    Directory of Open Access Journals (Sweden)

    Hesham Ahmed

    2016-08-01

    Full Text Available Near-net shape forming of metallic components from metallic powders produced in situ from reduction of corresponding pure metal oxides has not been explored to a large extent. Such a process can be probably termed in short as the “Reduction-Sintering” process. This methodology can be especially effective in producing components containing refractory metals. Additionally, in situ production of metallic powder from complex oxides containing more than one metallic element may result in in situ alloying during reduction, possibly at lower temperatures. With this motivation, in situ reduction of complex oxides mixtures containing more than one metallic element has been investigated intensively over a period of years in the department of materials science, KTH, Sweden. This review highlights the most important features of that investigation. The investigation includes not only synthesis of intermetallics and refractory metals using the gas solid reaction route but also study the reaction kinetics and mechanism. Environmentally friendly gases like H2, CH4 and N2 were used for simultaneous reduction, carburization and nitridation, respectively. Different techniques have been utilized. A thermogravimetric analyzer was used to accurately control the process conditions and obtain reaction kinetics. The fluidized bed technique has been utilized to study the possibility of bulk production of intermetallics compared to milligrams in TGA. Carburization and nitridation of nascent formed intermetallics were successfully carried out. A novel method based on material thermal property was explored to track the reaction progress and estimate the reaction kinetics. This method implies the dynamic measure of thermal diffusivity using laser flash method. These efforts end up with a successful preparation of nanograined intermetallics like Fe-Mo and Ni-W. In addition, it ends up with simultaneous reduction and synthesis of Ni-WN and Ni-WC from their oxide mixtures

  7. [High titer ethanol production from an atmospheric glycerol autocatalytic organosolv pretreated wheat straw].

    Science.gov (United States)

    Wang, Liang; Liu, Jianquan; Zhang, Zhe; Zhang, Feiyang; Ren, Junli; Sun, Fubao; Zhang, Zhenyu; Ding, Cancan; Lin, Qiaowen

    2015-10-01

    The expensive production of bioethanol is because it has not yet reached the 'THREE-HIGH' (High-titer, high-conversion and high-productivity) technical levels of starchy ethanol production. To cope with it, it is necessary to implement a high-gravity mash bioethanol production (HMBP), in which sugar hydrolysates are thick and fermentation-inhibitive compounds are negligible. In this work, HMBP from an atmospheric glycerol autocatalytic organosolv pretreated wheat straw was carried out with different fermentation strategies. Under an optimized condition (15% substrate concentration, 10 g/L (NH4)2SO4, 30 FPU/g dry matter, 10% (V/V) inoculum ratio), HMBP was at 31.2 g/L with a shaking simultaneous saccharification and fermentation (SSF) at 37 degrees C for 72 h, and achieved with a conversion of 73% and a productivity of 0.43 g/(L x h). Further by a semi-SFF with pre-hydrolysis time of 24 h, HMBP reached 33.7 g/L, the conversion and productivity of which was 79% and 0.47 g/(L x h), respectively. During the SSF and semi-SSF, more than 90% of the cellulose in both substrates were hydrolyzed into fermentable sugars. Finally, a fed-batch semi-SFF was developed with an initial substrate concentration of 15%, in which dried substrate (= the weight of the initial substrate) was divided into three portions and added into the conical flask once each 8 h during the first 24 h. HMBP achieved at 51.2 g/L for 72 h with a high productivity of 0.71 g/(L x h) while a low cellulose conversion of 62%. Interestingly, the fermentation inhibitive compound was mainly acetic acid, less than 3.0 g/L, and there were no other inhibitors detected, commonly furfural and hydroxymethyl furfural existing in the slurry. The data indicate that the lignocellulosic substrate subjected to the atmospheric glycerol autocatalytic organosolv pretreatment is very applicable for HMBP. The fed-batch semi-SFF is effective and desirable to realize an HMBP. PMID:26964336

  8. Exploring the control of land-atmospheric oscillations over terrestrial vegetation productivity

    Science.gov (United States)

    Depoorter, Mathieu; Green, Julia; Gentine, Pierre; Liu, Yi; van Eck, Christel; Regnier, Pierre; Dorigo, Wouter; Verhoest, Niko; Miralles, Diego

    2015-04-01

    Vegetation dynamics play an important role in the climate system due to their control on the carbon, energy and water cycles. The spatiotemporal variability of vegetation is regulated by internal climate variability as well as natural and anthropogenic forcing mechanisms, including fires, land use, volcano eruptions or greenhouse gas emissions. Ocean-atmospheric oscillations, affect the fluxes of heat and water over continents, leading to anomalies in radiation, precipitation or temperature at widely separated locations (i.e. teleconnections); an effect of ocean-atmospheric oscillations on terrestrial primary productivity can therefore be expected. While different studies have shown the general importance of internal climate variability for global vegetation dynamics, the control by particular teleconnections over the regional growth and decay of vegetation is still poorly understood. At continental to global scales, satellite remote sensing offers a feasible approach to enhance our understanding of the main drivers of vegetation variability. Traditional studies of the multi-decadal variability of global vegetation have been usually based on the normalized difference vegetation index (NDVI) derived from the Advanced Very High Resolution Radiometer (AVHRR), which extends back to the early '80s. There are, however, some limitations to NDVI observations; arguably the most important of these limitations is that from the plant physiology perspective the index does not have a well-defined meaning, appearing poorly correlated to vegetation productivity. On the other hand, recently developed records from other remotely-sensed properties of vegetation, like fluorescence or microwave vegetation optical depth, have proven a significantly better correspondence to above-ground biomass. To enhance our understanding of the controls of ocean-atmosphere oscillations over vegetation, we propose to explore the link between climate oscillation extremes and net primary productivity

  9. Products and mechanism of the reaction of ozone with phospholipids in unilamellar phospholipid vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Santrock, J.; Gorski, R.A.; O' Gara, J.F. (Biomedical Science Department, General Motors Research Laboratories, Warren, MI (United States))

    1992-01-01

    While considerable effort has been expended on determining the health effects of exposure to typical urban concentrations of O3, little is known about the chemical events responsible for toxicity. Phospholipids containing unsaturated fatty acids in the cell membranes of lung cells are likely reaction sites for inhaled ozone (O3). In this study, we examined the reaction of O3 with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in unilamellar phospholipid vesicles. Reaction of ozone with the carbon-carbon double bond of POPC yielded an aldehyde and a hydroxy hydroperoxide. The hydroxy hydroperoxide eliminated H2O2 to yield a second aldehyde. Upon further ozonolysis, the aldehydes were oxidized to the corresponding carboxylic acids. A material balance showed that no other reaction consumed POPC and O3 or produced these products. As a mechanistic probe, we measured incorporation of oxygen-18 from 18O3 into aldehyde, carboxylic acid, and H2O2. Approximately 50% of the aldehyde oxygen atoms were derived from O3. Oxygen in H2O2 was derived solely from O3, where both oxygen atoms in a molecule of H2O2 were from the same molecule of O3. One of the carboxylic acid oxygen atoms was derived from the precursor aldehyde, while the other was derived from O3. These results support the following mechanism. Cleavage of the carbon-carbon double bond of POPC by O3 yields a carbonyl oxide and an aldehyde. Reaction of H2O with the carbonyl oxide yields a hydroxy hydroperoxide, preventing formation ozonide by reaction of the carbonyl oxide and aldehyde. Elimination of H2O2 from the hydroxy hydroperoxide yields a second aldehyde. Oxidation of the aldehydes by O3 yields carboxylic acids.

  10. Product Yields and Characteristics of Corncob Waste under Various Torrefaction Atmospheres

    Directory of Open Access Journals (Sweden)

    Jau-Jang Lu

    2013-12-01

    Full Text Available Biomass is a promising energy source due to its abundant, carbon-fixing, and carbon-neutral properties. Torrefaction can be employed to improve the properties of biomass in an oxygen-free or nitrogen atmosphere. This study investigates the product yields and the solid product characteristics from corncob waste torrefaction at the temperatures of 250 °C and 300 °C for 1 h. Nitrogen, carbon dioxide, and a gas mixture of air and carbon dioxide are employed as the carrier gases. The solid product characteristics approach those of coal at the higher temperature, regardless of what the carrier gases are. The fixed carbon, higher heating value, and solid and energy yields using carbon dioxide as a carrier gas at 300 °C are close to those using nitrogen. The product safety and storage properties before and after torrefaction are revealed by the measurements of ignition temperature and hygroscopicity. A higher torrefaction temperature leads to a higher ignition temperature of treated biomass, except using the mixture of air and carbon dioxide as the carrier gas. Carbon dioxide is a better carrier gas than nitrogen for biomass torrefaction, from the storage and transportation points of view.

  11. TOPICAL REVIEW: Numerical modelling of atmospheric pressure gas discharges leading to plasma production

    Science.gov (United States)

    Georghiou, G. E.; Papadakis, A. P.; Morrow, R.; Metaxas, A. C.

    2005-10-01

    In this paper, we give a detailed review of recent work carried out on the numerical characterization of non-thermal gas discharge plasmas in air at atmospheric pressure. First, we briefly describe the theory of discharge development for dielectric barrier discharges, which is central to the production of non-equilibrium plasma, and we present a hydrodynamic model to approximate the evolution of charge densities. The model consists of the continuity equations for electrons, positive and negative ions coupled to Poisson's equation for the electric field. We then describe features of the finite element flux corrected transport algorithm, which has been developed to specifically aim for accuracy (no spurious diffusion or oscillations), efficiency (through the use of unstructured grids) and ease of extension to complex 3D geometries in the framework of the hydrodynamic model in gas discharges. We summarize the numerical work done by other authors who have applied different methods to various models and then we present highlights of our own work, which includes code validation, comparisons with existing results and modelling of radio frequency systems, dc discharges, secondary effects such as photoionization and plasma production in the presence of dielectrics. The extension of the code to 3D for more realistic simulations is demonstrated together with the adaptive meshing technique, which serves to achieve higher efficiency. Finally, we illustrate the versatility of our scheme by using it to simulate the transition from non-thermal to thermal discharges. We conclude that numerical modelling and, in particular, the extension to 3D can be used to shed new light on the processes involved with the production and control of atmospheric plasma, which plays an important role in a host of emerging technologies.

  12. Numerical modelling of atmospheric pressure gas discharges leading to plasma production

    Energy Technology Data Exchange (ETDEWEB)

    Georghiou, G E [Electronics and Computer Science, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Papadakis, A P [Electricity Utilization Group (EUG), Department of Engineering, University of Cambridge, Cambridge, CB2 1PZ (United Kingdom); Morrow, R [Applied and Plasma Physics, School of Physics, University of Sydney, Sydney, NSW (Australia); Metaxas, A C [St John' s College, University of Cambridge, Cambridge, CB2 1TP (United Kingdom)

    2005-10-21

    In this paper, we give a detailed review of recent work carried out on the numerical characterization of non-thermal gas discharge plasmas in air at atmospheric pressure. First, we briefly describe the theory of discharge development for dielectric barrier discharges, which is central to the production of non-equilibrium plasma, and we present a hydrodynamic model to approximate the evolution of charge densities. The model consists of the continuity equations for electrons, positive and negative ions coupled to Poisson's equation for the electric field. We then describe features of the finite element flux corrected transport algorithm, which has been developed to specifically aim for accuracy (no spurious diffusion or oscillations), efficiency (through the use of unstructured grids) and ease of extension to complex 3D geometries in the framework of the hydrodynamic model in gas discharges. We summarize the numerical work done by other authors who have applied different methods to various models and then we present highlights of our own work, which includes code validation, comparisons with existing results and modelling of radio frequency systems, dc discharges, secondary effects such as photoionization and plasma production in the presence of dielectrics. The extension of the code to 3D for more realistic simulations is demonstrated together with the adaptive meshing technique, which serves to achieve higher efficiency. Finally, we illustrate the versatility of our scheme by using it to simulate the transition from non-thermal to thermal discharges. We conclude that numerical modelling and, in particular, the extension to 3D can be used to shed new light on the processes involved with the production and control of atmospheric plasma, which plays an important role in a host of emerging technologies. (topical review)

  13. Reactions of clofibric acid with oxidative and reductive radicals—Products, mechanisms, efficiency and toxic effects

    International Nuclear Information System (INIS)

    The degradation of clofibric acid induced by hydroxyl radical, hydrated electron and O2−∙/HO2∙ reactive species was studied in aqueous solutions. Clofibric acid was decomposed more effectively by hydroxyl radical than by hydrated electron or O2−∙/HO2∙. Various hydroxylated, dechlorinated and fragmentation products have been identified and quantified. A new LC–MS method was developed based on 18O isotope labeling to follow the formation of hydroxylated derivatives of clofibric acid. Possible degradation pathways have been proposed. The overall degradation was monitored by determination of sum parameters like COD, TOC and AOX. It was found that the organic chlorine degrades very effectively prior to complete mineralization. After the treatment no toxic effect was found according to Vibrio fischeri tests. However, at early stages some of the reaction products were more harmful than clofibric acid. - Highlights: • Clofibric acid is effectively degraded by OH radical. • Main primary and secondary products are hydroxylated and dihydroxylated phenyl type derivatives of clofibric acid. • In air saturated aqueous solutions O2 plays an important role in decomposition of the aromatic structure. • A new LC–MS method with 18O-labeling was developed. • Early stage reaction products are more toxic to bacteria Vibrio fischeri than clofibric acid

  14. ASR prevention — Effect of aluminum and lithium ions on the reaction products

    Energy Technology Data Exchange (ETDEWEB)

    Leemann, Andreas, E-mail: andreas.leemann@empa.ch [Laboratory for Concrete/Construction Chemistry, Empa, Swiss Federal Laboratories for Material Science and Technology, Überlandstr. 129, 8600 Dübendorf (Switzerland); Bernard, Laetitia [Laboratory for Nanoscale Materials Science, Empa, Swiss Federal Laboratories for Material Science and Technology, Überlandstr. 129, 8600 Dübendorf (Switzerland); Alahrache, Salaheddine; Winnefeld, Frank [Laboratory for Concrete/Construction Chemistry, Empa, Swiss Federal Laboratories for Material Science and Technology, Überlandstr. 129, 8600 Dübendorf (Switzerland)

    2015-10-15

    In spite of the recent progress in the understanding of the mechanisms enabling aluminum-containing SCM like metakaolin and added LiNO{sub 3} to limit the extent of ASR in mortar and concrete, some gaps still remain. They concern mainly the effect of aluminum-containing SCM on the formed ASR products and the influence of aggregate characteristics on the effectiveness of LiNO{sub 3}. In this study, a model system, concrete and mortar were investigated by pore solution analysis, TGA, XRD, NMR, SEM combined with EDX and ToF-SIMS to address these questions. The amount of aluminum present in the pore solution of concrete and mortar is only able to slow down SiO{sub 2} dissolution but not to alter morphology, structure and composition of the reaction products. LiNO{sub 3} can suppress ASR by forming dense products protecting reactive minerals from further reaction. But its effectiveness is decreasing with increasing specific surface area of the reactive minerals in aggregates. - Highlights: • Aluminum of SCM slows down SiO{sub 2} dissolution. • Aluminum of SCM does not alter morphology and structure of ASR product. • ASR suppressing effect of LiNO{sub 3} depends on specific surface area of the aggregates.

  15. ASR prevention — Effect of aluminum and lithium ions on the reaction products

    International Nuclear Information System (INIS)

    In spite of the recent progress in the understanding of the mechanisms enabling aluminum-containing SCM like metakaolin and added LiNO3 to limit the extent of ASR in mortar and concrete, some gaps still remain. They concern mainly the effect of aluminum-containing SCM on the formed ASR products and the influence of aggregate characteristics on the effectiveness of LiNO3. In this study, a model system, concrete and mortar were investigated by pore solution analysis, TGA, XRD, NMR, SEM combined with EDX and ToF-SIMS to address these questions. The amount of aluminum present in the pore solution of concrete and mortar is only able to slow down SiO2 dissolution but not to alter morphology, structure and composition of the reaction products. LiNO3 can suppress ASR by forming dense products protecting reactive minerals from further reaction. But its effectiveness is decreasing with increasing specific surface area of the reactive minerals in aggregates. - Highlights: • Aluminum of SCM slows down SiO2 dissolution. • Aluminum of SCM does not alter morphology and structure of ASR product. • ASR suppressing effect of LiNO3 depends on specific surface area of the aggregates

  16. Production of isomers in compound and transfer reactions with {sup 4}He ions

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, S.A., E-mail: karamian@nrmail.jinr.ru [Joint Institute for Nuclear Research, Dubna 141980, Moscow Region (Russian Federation); Carroll, J.J., E-mail: james.j.carroll2@us.army.mil [Youngstown State University, Youngstown, OH 44555 (United States); Aksenov, N.V.; Albin, Y.A.; Bozhikov, G.A.; Dmitriev, S.N.; Starodub, G.Y.; Vostokin, G.K. [Joint Institute for Nuclear Research, Dubna 141980, Moscow Region (Russian Federation)

    2011-08-01

    A well-known island of nuclear isomerism appears near A=175-180 due to the deformation alignment of single-particle orbits at high angular momentum. This sometimes results in the formation of multi-quasiparticle states with record spin that are long-lived because of 'K-hindrance', i.e. symmetry re-arrangement. Production methods and spectroscopic studies of these isomers remain a challenge for modern nuclear reaction and nuclear structure physics. In the present work, activities were produced by irradiation of {sup 176}Yb (97.6% enriched) and {sup nat}Lu targets with 35 MeV {sup 4}He ions from the internal beam of the U-200 cyclotron. Induced activities were analyzed by applying the methods of radiochemistry and gamma spectroscopy. Yields of the compound and nucleon-transfer reactions were measured and the isomer-to-ground state ratios were deduced. Calculated results were obtained using standard procedures to reproduce the ({alpha}, xn) cross-sections, and the systematic behavior of the nucleon-transfer yields was established. The isomer-to-ground-state ratios for direct reactions with {sup 4}He ions were examined, resulting in a new characterization of the reaction mechanism.

  17. Influence of temperature inhomogeneity on product profile of reactions occurring within zeolites

    Indian Academy of Sciences (India)

    A V Anil Kumar; S Yashonath; G Ananthakrishna

    2003-10-01

    In zeolites, diffusion is often accompanied by a reaction or sorption which in turn can induce temperature inhomogeneities. Monte Carlo simulations of Lennard-Jones atoms in zeolite NaCaA are reported for the presence of a hot zone presumed to be created by a reaction or chemi- or physi-sorption site. These simulations show that the presence of localized hot regions can alter both kinetic and transport properties such as diffusion. Further, we show that enhancement of diffusion constant is greater for systems with larger barrier height, a surprising result that may be of considerable significance in many chemical and biological processes. We find an unanticipated coupling between reaction and diffusion due to the presence of a hot zone in addition to that which normally exists via concentration. Implications of this coupling for the product profile of a reaction are discussed. We also propose a mechanism by which mobility of ions or diffusion of molecular species within biomembranes may take place.

  18. Comparison of complementary reactions for the production of 261,262Bh

    International Nuclear Information System (INIS)

    Two heavy-ion induced fusion reactions producing 261,262Bh were studied using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. An excitation function for the production of 262Bh via the reaction 209Bi(54Cr,n)262Bh was measured with a maximum cross section from a fit to the data of 430 ± 110 pb observed at a compound nucleus excitation energy of 15.7 MeV. New data have been measured for the 1n exit channel of the 208Pb(55Mn, n)262Bh reaction. We present an updated excitation function with an observed maximum cross section of 530±100 pb at a compound nucleus excitation energy of 14.1 MeV. Events corresponding to the 2n exit channel for the 209Bi(54Cr,2n)261Bh and 208Pb(55Mn,2n)261Bh reactions were also observed and are presented as partial excitation functions. The measured decay properties correspond well with existing experimental data. We compare these experimental results to cross section predictions from a model by Swiatecki et al. and discuss entrance channel effects on the magnitude of 1n cross sections

  19. Coupled Pervaporation-Reaction Distillation Process for the Production of n-Bromopropane

    Institute of Scientific and Technical Information of China (English)

    毛澄宇; 余立新; 郭庆丰; 席春光

    2002-01-01

    The reaction of n-C3H7OH+HBr=n-C3H7Br+H2O was used to experimentally study a coupled pervaporation (PV)-reaction distillation (RD) process. The results show that polyvinyl alcohol (PVA) is a suitable membrane material for water removal. The typical separation properties of PVA polyacrylonitrile (PAN) composite membranes are a highest flux of 780 g/(m2*h) and a separation factor of 840 for the C3H7OH concentration in the original feed of 95% at 90℃ and below 3300 Pa(abs). Reaction distillation produced the n-bromopropane from the distillation column as a ternary azeotropic liquid mixture of C3H7OH, H2O and C3H7Br, with a product concentration of about 92%. The coupled PV-RD membrane reactor experiment shows that the BrPr yield can reach 92%, much higher than that for reaction-distillation without pervaporation.

  20. Production of isomers in compound and transfer reactions with 4He ions

    International Nuclear Information System (INIS)

    A well-known island of nuclear isomerism appears near A=175-180 due to the deformation alignment of single-particle orbits at high angular momentum. This sometimes results in the formation of multi-quasiparticle states with record spin that are long-lived because of 'K-hindrance', i.e. symmetry re-arrangement. Production methods and spectroscopic studies of these isomers remain a challenge for modern nuclear reaction and nuclear structure physics. In the present work, activities were produced by irradiation of 176Yb (97.6% enriched) and natLu targets with 35 MeV 4He ions from the internal beam of the U-200 cyclotron. Induced activities were analyzed by applying the methods of radiochemistry and gamma spectroscopy. Yields of the compound and nucleon-transfer reactions were measured and the isomer-to-ground state ratios were deduced. Calculated results were obtained using standard procedures to reproduce the (α, xn) cross-sections, and the systematic behavior of the nucleon-transfer yields was established. The isomer-to-ground-state ratios for direct reactions with 4He ions were examined, resulting in a new characterization of the reaction mechanism.

  1. Evaluation of selected detector systems for products formed in the atmospheric hydrolysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    Sensitive detection of UF6 hydrolysis products, either by discontinuous sampling or by continuous or near real-time monitoring, is an important safety consideration for DOE contractors handling large quantities of UF6. Automated continuous or rapid intermittent remote sensing of these reaction products can provide an alarm signal when a preselected threshold value has been exceeded (absolute response) or when a significant emission excursion has occurred (rate of change of response). This report evaluates the performance of selected devices for the detection of airborne materials formed in the release of liquid UF6 (≅1.3 g) into an enclosed volume of 6 m3; these experiments were initiated on October 23, 1986. The detection principles investigated are: photometric, gas detector tubes, and electrochemical sensor

  2. Biorefining: heterogeneously catalyzed reactions of carbohydrates for the production of furfural and hydroxymethylfurfural.

    Science.gov (United States)

    Karinen, Reetta; Vilonen, Kati; Niemelä, Marita

    2011-08-22

    Furfurals are important intermediates in the chemical industry. They are typically produced by homogeneous catalysis in aqueous solutions. However, heterogeneously catalyzed processes would be beneficial in view of the principles of green chemistry: the elimination of homogeneous mineral acids makes the reaction mixtures less corrosive, produces less waste, and facilitates easy separation and recovery of the catalyst. Finding an active and stable water-tolerant solid acid catalyst still poses a challenge for the production of furfural (furan-2-carbaldehyde) and 5-(hydroxymethyl)-2-furaldehyde (HMF). Furfural is produced in the dehydration of xylose, and HMF is formed from glucose and fructose in the presence of an acidic catalyst. Bases are not active in dehydration reaction but do catalyze the isomerization of monosaccharides, which is favorable when using glucose as a raw material. In addition to the desired dehydration of monosaccharides, many undesired side reactions take place, reducing the selectivity and deactivating the catalyst. In addition, the catalyst properties play an important role in the selectivity. In this Review, catalytic conversion approaches are summarized, focusing on the heterogeneously catalyzed formation of furfural. The attractiveness of catalytic concepts is evaluated, keeping in mind productivity, sustainability, and environmental footprint. PMID:21728248

  3. Characterization and validation of methane products from the Atmospheric Infrared Sounder (AIRS)

    Science.gov (United States)

    Xiong, Xiaozhen; Barnet, Chris; Maddy, Eric; Sweeney, Colm; Liu, Xingpin; Zhou, Lihang; Goldberg, Mitch

    2008-09-01

    This paper presents the characterization and validation of retrievals of atmospheric methane (CH4) vertical profiles by the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua platform. AIRS channels near 7.6 μm are used for CH4 retrieval, and they are most sensitive to the middle to upper troposphere, i.e., about 200-300 hPa in the tropics and 400-500 hPa in the polar region. The atmospheric temperature-humidity profiles, surface skin temperature, and emissivity required to derive CH4 are obtained from retrievals using separate AIRS channels and the Advanced Microwave Sounding Unit (AMSU). Comparison of AIRS retrieved profiles with some in situ aircraft CH4 profiles implied that the forward model used in the AIRS retrieval system V4.0 required a 2% increase in methane absorption coefficients for strong absorption channels, and this bias adjustment was implemented in the AIRS retrieval system V5.0. As a new operational product in V5.0, AIRS CH4 were validated using in situ aircraft observations at 22 sites of the NOAA Earth System Research Laboratory, Global Monitoring Division (NOAA/ESRL/GMD), ranging from the Arctic to the tropical South Pacific Ocean, but their altitudes are usually above 300 hPa. The results show the bias of the retrieved CH4 profiles for this version is -1.4˜0.1% and its RMS difference is about 0.5-1.6%, depending on altitude. These validation comparisons provide critical assessment of the retrieval algorithm and will continue using more in situ observations together with future improvement to the retrieval algorithm. AIRS CH4 products include not only the CH4 profile but also the information content. As examples, the products of AIRS CH4 in August 2004 and the difference of CH4 in May and September 2004 are shown. From these results a few features are evident: (1) a large AIRS CH4 plume southwest of the Tibetan plateau that may be associated with deep convection during the Asian summer monsoon; (2) high mixing ratios of AIRS CH4 in

  4. Oxidation of Annelated Diarylamines: Analysis of Reaction Pathways to Nitroxide Diradical and Spirocyclic Products

    Energy Technology Data Exchange (ETDEWEB)

    Rajca, Andrzej; Shiraishi, Kouichi; Boraty; #324; ski, Przemyslaw J.; Pink, Maren; Miyasaka, Makoto; Rajca, Suchada (UNL); (Indiana)

    2012-02-06

    Oxidation of diaryldiamine 2, a tetrahydrodiazapentacene derivative, provides diarylnitroxide diradical 1 accompanied by an intermediate nitroxide monoradical and a multitude of isolable diamagnetic products. DFT-computed tensors for EPR spectra and paramagnetic {sup 1}H NMR isotropic shifts for nitroxide diradical 1 show good agreement with the experimental EPR spectra in rigid matrices and paramagnetic {sup 1}H NMR spectra in solution, respectively. Examination of the diamagnetic products elucidates their formation via distinct pathways involving C-O bond-forming reactions, including Baeyer-Villiger-type oxidations. An unusual diiminoketone structure and two spirocyclic structures of the predominant diamagnetic products are confirmed by either X-ray crystallography or correlations between DFT-computed and experimental spectroscopic data such as {sup 1}H, {sup 13}C, and {sup 15}N NMR chemical shifts and electronic absorption spectra.

  5. Immunoassay utilizing biochemistry reaction product via surface-enhanced Raman scattering in near field

    Institute of Scientific and Technical Information of China (English)

    ZHAO Haiying; NI Yi; JIANG Wei; LUO Peiqing; HUANG Meizheng; YIN Guangzhong; DOU Xiaoming

    2005-01-01

    We propose here a kind of applications of surface-enhanced Raman scattering (SERS) to immunology. It is a new enzyme immunoassay based on SERS. In the proposed system, antibody immobilized on a solid substrate reacts with antigen, which binds with another antibody labeled with peroxidase. If this immunocomplex is subjected to reaction with o-phenylenediamine and hydrogenperoxide, azoaniline is generated. This azo compound is adsorbed on a silver colloid and only the azo compound gives a strong surface-enhanced resonance Raman (SERRS) spectrum. A linear relationship was observed between the peak intensity of the N=N stretching band and the concentration of antigen, revealing that one can determine the concentration of antigen by the SERRS measurement of the reaction product. The detection limit of this SERS enzyme immunoassay method was found to be about 10-15 mol/L.

  6. Production of the superheavy baryon Λc anti c*(4209) in kaon-induced reaction

    International Nuclear Information System (INIS)

    The production of superheavy Λc anti c*(4209) baryon in the K-p → ηcΛ process via s-channel is investigated with an effective Lagrangian approach and the isobar model. Moreover, the background from the K-p → ηcΛ reaction through the t-channel with K* exchange and u-channel with nucleon exchange are also considered. The numerical results indicate it is feasible to search for the superheavy Λc anti c*(4209) via K-p scattering. The relevant calculations not only shed light on the further experiment of searching for the Λc anti c*(4209) through kaon-induced reaction, but also enable us to have a better understanding of the exotic baryons. (orig.)

  7. An update on measurements of helium-production reactions with a spallation neutron source

    International Nuclear Information System (INIS)

    This report gives the status, updated since the last Research Coordination Meeting, of alpha-particle production cross sections, emission spectra and angular distributions which we are measuring at the spallation source of fast neutrons at the Los Alamos Meson Physics Facility (LAMPF). Detectors at angles of 30, 60, 90 and 135 degrees are used to identify alpha particles, measure their energy spectra, and indicate the time-of-flight, and hence the energy, of the neutrons inducing the reaction. The useful neutron energy ranges from less than 1 MeV to approximately 50 MeV for the present experimental setup. Targets under study at present include C, N, 0, 27Al, Si, 51V, 56Fe, 59CO, 58,60Ni, 89Y and 93Nb. Data for 59Co have been re-analyzed. The results illustrate the capabilities of the approach, agreement with literature values, and comparisons with nuclear reaction model calculations

  8. Production of specific structured lipids by enzymatic interesterification: optimization of the reaction by response surface design

    DEFF Research Database (Denmark)

    Xu, Xuebing; Skands, Anja Rebecca Havegaard; Adler-Nissen, Jens; Høy, Carl-Erik

    1998-01-01

    Rapeseed oil and capric acid were interesterified in solvent-free media catalyzed by Lipozyme IM (Rhizomucor miehei) to produce specific-structured lipids (SSLs). The process was optimized by response surface design concerning the effects of acyl migration and the by-products of diacylglycerols...... (DAGs). A five-factor response surface design was used to evaluate the influences of five major factors and their relationships. The five factors were water content (Wc, wt% based on enzyme used), reaction temperature (Te,°C), enzyme load (El, wt% based on substrates), reaction time (Tr, hour) and...... had strong influence on the net incorporation and the experimental and predicted values were close. The best fitting quadratic model was determined by regression and backward elimination. The coefficients of determination (R2) of the models were 0.971 for net incorporation and 0.938 for DAG content...

  9. Increase of rutin antioxidant activity by generating Maillard reaction products with lysine.

    Science.gov (United States)

    Zhang, Ru; Zhang, Bian-Ling; He, Ting; Yi, Ting; Yang, Ji-Ping; He, Bin

    2016-06-01

    Rutin exists in medicinal herbs, fruits, vegetables, and a number of plant-derived sources. Dietary sources containing rutin are considered beneficial because of their potential protective roles in multiple diseases related to oxidative stresses. In the present study, the change and antioxidation activity of rutin in Maillard reaction with lysine through a heating process were investigated. There is release of glucose and rhamnose that interact with lysine to give Maillard reaction products (MRPs), while rutin is converted to less-polar quercetin and a small quantity of isoquercitrin. Because of their high cell-membrane permeability, the rutin-lysine MRPs increase the free radical-scavenging activity in HepG2 cells, showing cellular antioxidant activity against Cu(2+)-induced oxidative stress higher than that of rutin. Furthermore, the MRPs significantly increased the Cu/Zn SOD (superoxide dismutase) activity and Cu/Zn SOD gene expression of HepG2 cells, consequently enhancing antioxidation activity. PMID:27106712

  10. Multi-nucleon transfer reactions for production and study of heavy neutron rich nuclei

    International Nuclear Information System (INIS)

    The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N = 126 is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be rather high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. A new setup is proposed to produce and investigate heavy neutron-rich nuclei located along the neutron closed shell N=126.

  11. Synergistic Effects of Turbine Wakes and Atmospheric Stability on Power Production at an Onshore Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Lundquist, J K; Marjanovic, N

    2012-01-25

    This report examines the complex interactions between atmospheric stability and turbine-induced wakes on downwind turbine wind speed and power production at a West Coast North American multi-MW wind farm. Wakes are generated when the upwind flow field is distorted by the mechanical movement of the wind turbine blades. This has two consequences for downwind turbines: (1) the downwind turbine encounters wind flows with reduced velocity and (2) the downwind turbine encounters increased turbulence across multiple length scales via mechanical turbulence production by the upwind turbine. This increase in turbulence on top of ambient levels may increase aerodynamic fatigue loads on the blades and reduce the lifetime of turbine component parts. Furthermore, ambient atmospheric conditions, including atmospheric stability, i.e., thermal stratification in the lower boundary layer, play an important role in wake dissipation. Higher levels of ambient turbulence (i.e., a convective or unstable boundary layer) lead to higher turbulent mixing in the wake and a faster recovery in the velocity flow field downwind of a turbine. Lower levels of ambient turbulence, as in a stable boundary layer, will lead to more persistent wakes. The wake of a wind turbine can be divided into two regions: the near wake and far wake, as illustrated in Figure 1. The near wake is formed when the turbine structure alters the shape of the flow field and usually persists one rotor diameter (D) downstream. The difference between the air inside and outside of the near wake results in a shear layer. This shear layer thickens as it moves downstream and forms turbulent eddies of multiple length scales. As the wake travels downstream, it expands depending on the level of ambient turbulence and meanders (i.e., travels in non-uniform path). Schepers estimates that the wake is fully expanded at a distance of 2.25 D and the far wake region begins at 2-5 D downstream. The actual distance traveled before the wake

  12. Hadron Production for the Neutrino Factory and for the Atmospheric Neutrino Flux

    CERN Multimedia

    2002-01-01

    The HARP experiment carries out, at the CERN PS, a programme of measurements of secondary hadron production, over the full solid angle, produced on thin and thick nuclear targets by beams of protons and pions with momenta in the range 2 to 15~\\GeVc. The first aim of this experiment is to acquire adequate knowledge of pion yields for an optimal design of the proton driver of the Neutrino Factory. The second aim is to reduce substantially the existing $\\sim 30$\\% uncertainty in the calculation of absolute atmospheric neutrino fluxes and the $\\sim 7$\\% uncertainty in the ratio of neutrino flavours, required for a refined interpretation of the evidence for neutrino oscillation from the study of atmospheric neutrinos in present and forthcoming experiments. The HARP experiment comprises a large-acceptance charged-particle magnetic spectrometer of conventional design, located in the East Hall of the CERN PS and using the T9 tagged charged-particle beam. The main detector is a cylindrical TPC inside a solenoid magnet...

  13. Elevated Atmospheric CO2 Affects Ectomycorrhizal Species Abundance and Increases Sporocarp Production under Field Conditions

    Directory of Open Access Journals (Sweden)

    Douglas L. Godbold

    2015-04-01

    Full Text Available Anthropogenic activities during the last century have increased levels of atmospheric CO2. Forest net primary productivity increases in response to elevated CO2, altering the quantity and quality of carbon supplied to the rhizosphere. Ectomycorrhizal fungi form obligate symbiotic associations with the fine roots of trees that mediate improved scavenging for nutrients in exchange for a carbohydrate supply. Understanding how the community structure of ectomycorrhizal fungi is altered by climate change is important to further our understanding of ecosystem function. Betula pendula and Fagus sylvatica were grown in an elevated CO2 atmosphere delivered using free air carbon dioxide enrichment (FACE under field conditions in the U.K., and Picea abies was grown under elevated CO2 in glass domes in the Czech Republic. We used morphotyping and sequencing of the internal transcribed spacer region of the fungal ribosomal operon to study ectomycorrhizal community structure. Under FACE, un-colonised roots tips increased in abundance for Fagus sylvatica, and during 2006, sporocarp biomass of Peziza badia significantly increased. In domes, ectomycorrhizal community composition shifted from short-distance and smooth medium-distance to contact exploration types. Supply and competition for carbon belowground can influence ectomycorrhizal community structure with the potential to alter ecosystem function.

  14. Application of multisection packing concept to sorption-enhanced steam methane reforming reaction for high-purity hydrogen production

    Science.gov (United States)

    Lee, Chan Hyun; Mun, Sungyong; Lee, Ki Bong

    2015-05-01

    Hydrogen has been gaining popularity as a new clean energy carrier, and bulk hydrogen production is achieved through the steam methane reforming (SMR) reaction. Since hydrogen produced via the SMR reaction contains large amounts of impurities such as unreacted reactants and byproducts, additional purification steps are needed to produce high-purity hydrogen. By applying the sorption-enhanced reaction (SER), in which catalytic reaction and CO2 byproduct removal are carried out simultaneously in a single reactor, high-purity hydrogen can be directly produced. Additionally, the thermodynamic limitation of conventional SMR reaction is circumvented, and the SMR reaction process becomes simplified. To improve the performance of the SER, a multisection packing concept was recently proposed. In this study, the multisection packing concept is experimentally demonstrated by applying it to a sorption-enhanced SMR (SE-SMR) reaction. The experimental results show that the SE-SMR reaction is significantly influenced by the reaction temperature, owing to the conflicting dependence of the reaction rate and the CO2 sorption uptake on the reaction temperature. Additionally, it is confirmed that more high-purity hydrogen (<10 ppm of CO) can be produced by applying the multisection packing concept to the SE-SMR reactions operated at sufficiently high temperatures where the SMR reaction is not limited by rate.

  15. Novel Production Method for Plant Polyphenol from Livestock Excrement Using Subcritical Water Reaction

    Directory of Open Access Journals (Sweden)

    Mayu Yamamoto

    2008-01-01

    Full Text Available Plant polyphenol, including vanillin, is often used as the intermediate materials of the medicines and vanilla flavoring. In agriculture generally vanillin is produced from vanilla plant and in industry from lignin of disposed wood pulp. We have recently developed a method for the production of plant polyphenol with the excrement as a natural resource of lignin, of the herbivorous animals, by using the subcritical water. The method for using the subcritical water is superior to that of the supercritical water because in the latter complete decomposition occurs. We have successfully produced the vanillin, protocatechuic acid, vanillic acid, and syringic acid in products. Our method is simpler and more efficient not only because it requires the shorter treatment time but also because it releases less amount of carbon dioxide into the atmosphere.

  16. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment.

    Science.gov (United States)

    Qu, Ruijuan; Feng, Mingbao; Wang, Xinghao; Huang, Qingguo; Lu, Junhe; Wang, Liansheng; Wang, Zunyao

    2015-01-01

    Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters. PMID:26430733

  17. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment.

    Directory of Open Access Journals (Sweden)

    Ruijuan Qu

    Full Text Available Tetrabromobisphenol A (TBBPA is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters.

  18. Preventive effect of fermented Maillard reaction products from milk proteins in cardiovascular health.

    Science.gov (United States)

    Oh, N S; Kwon, H S; Lee, H A; Joung, J Y; Lee, J Y; Lee, K B; Shin, Y K; Baick, S C; Park, M R; Kim, Y; Lee, K W; Kim, S H

    2014-01-01

    The aim of this study was to determine the dual effect of Maillard reaction and fermentation on the preventive cardiovascular effects of milk proteins. Maillard reaction products (MRP) were prepared from the reaction between milk proteins, such as whey protein concentrates (WPC) and sodium caseinate (SC), and lactose. The hydrolysates of MRP were obtained from fermentation by lactic acid bacteria (LAB; i.e., Lactobacillus gasseri H10, L. gasseri H11, Lactobacillus fermentum H4, and L. fermentum H9, where human-isolated strains were designated H1 to H15), which had excellent proteolytic and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities (>20%). The antioxidant activity of MRP was greater than that of intact proteins in assays of the reaction with 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and trivalent ferric ions; moreover, the effect of MRP was synergistically improved by fermentation. The Maillard reaction dramatically increased the level of antithrombotic activity and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) inhibitory effect of milk proteins, but did not change the level of activity for micellar cholesterol solubility. Furthermore, specific biological properties were enhanced by fermentation. Lactobacillus gasseri H11 demonstrated the greatest activity for thrombin and HMGR inhibition in Maillard-reacted WPC, by 42 and 33%, respectively, whereas hydrolysates of Maillard-reacted SC fermented by L. fermentum H9 demonstrated the highest reduction rate for micellar cholesterol solubility, at 52%. In addition, the small compounds that were likely released by fermentation of MRP were identified by size-exclusion chromatography. Therefore, MRP and hydrolysates of fermented MRP could be used to reduce cardiovascular risks. PMID:24731635

  19. Electronic Nose Monitoring the Maillard Reaction Flavors of Sesame Oil from Different Production Processes

    Directory of Open Access Journals (Sweden)

    Su Dong-Yang

    2014-07-01

    Full Text Available The objective in this study was to evaluate the capacity of electronic nose to monitoring the effect of different Maillard reaction processes on natural flavors of sesame oil, using a specific Electronic Nose device (PEN3. The flavors were prepared by Maillard reaction using chemical constituents from water extract of Lentinus and other precursors. The optimum conditions of reaction process was determined by using orthogonal test design, then an Electronic Nose (PEN3was used to characterize and classify eight different flavors from different reaction process and sesame oil from market. This method firstly sampled aroma composition emanating from the flavors by PEN3 systems and then obtained response values of PEN3. Principal Component Analysis (PCA and Linear Discriminant Analysis (LDA were used in order to investigate whether the electronic nose was able to distinguish among different Maillard Reaction Production (MRP. The loadings analysis was used to identify the sensors responsible for discrimination in the current pattern file. The results of this study showed that the basic components added with lysine, xylose and glycerin, heated in glycerine bath at 140C for 120 min, was a novel flavors with sesame oil flavor and taste. The electronic nose PEN 3 can discriminate successfully different MRPs using both PCA and LDA analysis. But, it was not able to detect a clear difference in the sample of similar aroma with sesame oil using PCA analysis. Some sensors have the highest influence in the current pattern file for electronic nose PEN 3. A subset of few sensors can be chosen to explain all the variance. This result could be used in further studies to optimize the number of sensors.

  20. Oxidation of triclosan by ferrate: Reaction kinetics, products identification and toxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Yang Bin [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Ying Guangguo, E-mail: guang-guo.ying@csiro.au [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhao Jianliang; Zhang Lijuan; Fang Yixiang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Nghiem, Long Duc [School of Civil Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2011-02-15

    Research highlights: {yields} Triclosan reacted rapidly with ferrate. {yields} Oxidation resulted in a decrease in algal toxicity. {yields} No inhibition of algae growth from ferrate. - Abstract: The oxidation of triclosan by commercial grade aqueous ferrate (Fe(VI)) was investigated and the reaction kinetics as a function of pH (7.0-10.0) were experimentally determined. Intermediate products of the oxidation process were characterized using both GC-MS and RRLC-MS/MS techniques. Changes in toxicity during the oxidation process of triclosan using Fe(VI) were investigated using Pseudokirchneriella subcapitata growth inhibition tests. The results show that triclosan reacted rapidly with Fe(VI), with the apparent second-order rate constant, k{sub app}, being 754.7 M{sup -1} s{sup -1} at pH 7. At a stoichiometric ratio of 10:1 (Fe(VI):triclosan), complete removal of triclosan was achieved. Species-specific rate constants, k, were determined for reaction of Fe(VI) with both the protonated and deprotonated triclosan species. The value of k determined for neutral triclosan was 6.7({+-}1.9) x 10{sup 2} M{sup -1} s{sup -1}, while that measured for anionic triclosan was 7.6({+-}0.6) x 10{sup 3} M{sup -1} s{sup -1}. The proposed mechanism for the oxidation of triclosan by the Fe(VI) involves the scission of ether bond and phenoxy radical addition reaction. Coupling reaction may also occur during Fe(VI) degradation of triclosan. Overall, the degradation processes of triclosan resulted in a significant decrease in algal toxicity. The toxicity tests showed that Fe(VI) itself dosed in the reaction did not inhibit green algae growth.

  1. Oxidation of triclosan by ferrate: Reaction kinetics, products identification and toxicity evaluation

    International Nuclear Information System (INIS)

    Research highlights: → Triclosan reacted rapidly with ferrate. → Oxidation resulted in a decrease in algal toxicity. → No inhibition of algae growth from ferrate. - Abstract: The oxidation of triclosan by commercial grade aqueous ferrate (Fe(VI)) was investigated and the reaction kinetics as a function of pH (7.0-10.0) were experimentally determined. Intermediate products of the oxidation process were characterized using both GC-MS and RRLC-MS/MS techniques. Changes in toxicity during the oxidation process of triclosan using Fe(VI) were investigated using Pseudokirchneriella subcapitata growth inhibition tests. The results show that triclosan reacted rapidly with Fe(VI), with the apparent second-order rate constant, kapp, being 754.7 M-1 s-1 at pH 7. At a stoichiometric ratio of 10:1 (Fe(VI):triclosan), complete removal of triclosan was achieved. Species-specific rate constants, k, were determined for reaction of Fe(VI) with both the protonated and deprotonated triclosan species. The value of k determined for neutral triclosan was 6.7(±1.9) x 102 M-1 s-1, while that measured for anionic triclosan was 7.6(±0.6) x 103 M-1 s-1. The proposed mechanism for the oxidation of triclosan by the Fe(VI) involves the scission of ether bond and phenoxy radical addition reaction. Coupling reaction may also occur during Fe(VI) degradation of triclosan. Overall, the degradation processes of triclosan resulted in a significant decrease in algal toxicity. The toxicity tests showed that Fe(VI) itself dosed in the reaction did not inhibit green algae growth.

  2. Atmospheric chemistry of HFC-134a. Kinetic and mechanistic study of the CF3CFHO2 + NO2 reaction

    DEFF Research Database (Denmark)

    Møgelberg, T.E.; Nielsen, O.J.; Sehested, J.; Wallington, T.J.; Hurley, M.D.; Schneider, W.F.

    -transform infrared technique was used to investigate the thermal decomposition of the product CF3CFHO2NO2. At 296 K in the presence of 700 Torr of air, decomposition of CF3CFHO2NO2 was rapid (greater than 90% decomposition within 3 min). The results are discussed in the context of atmospheric chemistry of CF3CFH2...

  3. Methods for measuring radon and radon daughter products in underground and free-atmosphere air

    International Nuclear Information System (INIS)

    Various instruments and methods suitable for obtaining data on radon and, in particular, radon daughter products in air have been developed by the National Board of Nuclear Safety and Radiation Protection of the German Democratic Republic: (a) The potential alpha-energy concentration of radon daughters is checked by a small (2.2 kg) working-level meter especially designed for mine conditions. A diaphragm pump, filter holder and surface-barrier detector are the integral components. The sensitivity of the battery-operated instrument makes it possible to determine the potential alpha-energy concentration over the range 4x103 to 100x103 MeV/ltr; (b) A special method is used for making quasi-continuous measurements of the long-term fluctuations of radon daughter-product concentrations; (c) Methods of sufficiently high sensitivity have been developed to determine low concentrations of 222Rn and its short-lived decay products in the free atmosphere; (d) For integrating radon-daughter measurements under varying inhalation conditions, a battery-operated, pocket-sized device was developed. It consists of a small diaphragm pump, a filter disc and two thermoluminescent detectors in a compact arrangement. The minimum detection limit for a 168-hour integration time is 105 MeV.h/ltr for a 2 ltr/h air flow rate. The same filter-TLD combination fitted with a special injector unit instead of the battery-operated pump can also be used as a stationary monitor. (author)

  4. Absolute production rate measurements of nitric oxide by an atmospheric pressure plasma jet (APPJ)

    Energy Technology Data Exchange (ETDEWEB)

    Pipa, A V; Bindemann, T; Foest, R; Kindel, E; Roepcke, J; Weltmann, K-D [Leibniz-Institut fuer Plasmaforschung and Technologie e.V. (INP), Felix-Hausdorff Strasse 2, D-17489 Greifswald (Germany)], E-mail: foest@inp-greifswald.de

    2008-10-07

    Tunable diode laser absorption spectroscopy (TDLAS) has been applied to measure the absolute production rate of NO molecules in the gas phase of an atmospheric pressure plasma jet (APPJ) operating at rf (13.56 MHz) in argon with small (up to 1%) admixtures of air. The resulting NO production rates were found to be in the range (0.1-80) x 10{sup -3} sccm or (0.05-35) x 10{sup 18} molecules s{sup -1} depending on the experimental conditions. Maximum rates were obtained at 0.2% air. For TDLAS measurements the APPJ was arranged inside an astigmatic multi-pass cell of Herriott type with 100 m absorption length. The insertion into a closed volume differs slightly from the normal, open operation with the jet propagating freely into air. Therefore, the measuring results are compared with optical emission of the open jet to verify equivalent experimental conditions. The dependence of the optical emission of NO (237 nm) on power and gas mixture has been measured. The similar shape of the dependence of absorption and emission signals gives evidence that the comparability of experimental conditions is sufficiently satisfied. It is concluded that the NO production rate of the APPJ in ambient air can be characterized using TDLAS and provides reliable results in spite of differing experimental conditions due to the set-up.

  5. Meson production and nuclear fragmentation of the nuclei in the atmosphere

    International Nuclear Information System (INIS)

    Propagation of primary and secondary cosmic rays in the atmosphere is calculated analytically. Two different cases of primary-cosmic-ray composition are used: the first case assumes a mixed composition of very heavy, heavy, middle, and α nuclei and nucleons; the second case considers only nucleons in the primary-cosmic-ray flux. The mechanism of multiple meson production is formulated according to the wounded-nucleon model for a nucleus-nucleus interaction and the scaling model for a nucleon-nucleon interaction. The mechanism of nuclear fragmentation is formulated according to experimental values of the fragmentation parameters at low energy. The calculated results of the electromagnetic flux are compared with the results of mountain experiments with a large-scale emulsion chamber and experimental data at airplane altitudes. From these comparisons the model with heavy nuclei gives the best fit

  6. New instruments and methods for measuring the concentration of radioactive products in the atmosphere

    International Nuclear Information System (INIS)

    Different recorders for radioactive aerosols have been developed for measuring the pollution of the atmosphere in laboratories or the external atmosphere. EAR 600. - Allows continuous measurement, instantaneously and 3 to 10 hours after sampling, of concentrations of α or β emitting aerosols varying between some 10-11 and some 10-8 curie per cubic metre of air. EAR 800. - Allows continuous measurement of concentration of α emitting aerosols varying between 10-11 and 10-5 curie per cubic metre of air and concentration of β emitting aerosols from 10-11 to 10-1 curie per cubic metre of air. EAR Plutonium. - Allows detection after several minutes of 1000 MPD (2 x 10-9 curie par cubic metre), and after 8 hours 1 MPD (2 x 10-12 curie per cubic metre). Two methods are used to separate the activity due to plutonium from that due to the descendants of radon and thoron: a) by amplitude discrimination, b) by RaC-RaC' and ThC-ThC' (α β ) coincidences. SP4. This system, mounted on a jeep, allows the measurement of irradiation produced on the ground by the smoke from the piles. The sensitivity is 5μR/h. A.D.I.R. - This autonomous and portable instrument is designed for the instantaneous measurement of the radon content of the atmosphere in mines. It allows the measurement of contents in air varying between 0.4 and 400 x 10-10 curie per litre of air (0.4 and 400 MPD). The measurement of radioactive fall-out is carried out after collection of this activity by a special rain gauge which comprises an adhesive surface and a tube containing ion exchange resins. The radioactivity of the fall-out varies between some 10-9 and some 10-7 curie per square metre per month. Concentrations in fission products of the atmosphere are measured after collecting on filter paper. Concentrations measured in air at ground level vary between 10-13 and 10-12 curie per cubic metre. (author)

  7. ESR evidence for radical production from the reaction of ozone with unsaturated lipids

    Energy Technology Data Exchange (ETDEWEB)

    Church, D.F.; McAdams, M.L..; Pryor, W.A. (Louisiana State Univ., Baton Rouge, (United States))

    1991-03-15

    The authors report electron spin resonance (ESR) spin trapping evidence for radical production by the reaction of ozone with unsaturated compounds. Soy and egg phosphatidylcholine liposomes, fatty acid emulsions, and homogeneous aqueous solutions of 3-hexenoic acid were treated with ozone in the presence of the spin trap {alpha}-phenyl-N-tert-butyl nitrone (PBN). Under these conditions, they observe spin adducts resulting from the trapping of both organic carbon- and oxygen-centered radicals. When the lipid-soluble antioxidant alpha-tocopherol is included in the liposomal systems, the formation of spin adducts is completely inhibited. The authors suggest that radicals giving rise to these spin adducts arise form the rapid decomposition of the 1,2,3-trioxolane intermediate that is initially formed when ozone reacts with the carbon-carbon double bonds of the substrates. These free radicals are not formed by the decomposition of the Criegee ozonide, since little of the ozonide is formed in the presence of water. Although hydrogen peroxide is the predominate peroxidic product of the ozone/alkene reaction, its decomposition is not responsible for the observed radical production since neither catalase nor iron chelators significantly affect the spin adduct yield. The radical yield is approximately 1%. Since a polyunsaturated fatty acid (PUFA) such as linoleic acid produces much higher concentrations of spin trappable radicals than does the monounsaturated fatty oleic acid, the results also suggest that sites in the lung containing higher levels of PUFA may be an important target for radical formation.

  8. Encapsulation of ascorbic acid promotes the reduction of Maillard reaction products in UHT milk.

    Science.gov (United States)

    Troise, Antonio Dario; Vitiello, Daniele; Tsang, Catherine; Fiore, Alberto

    2016-06-15

    The presence of amino groups and carbonyls renders fortified milk with ascorbic acid particularly susceptible to the reduction of available lysine and to the formation of Maillard reaction products (MRPs), as Nε-(carboxyethyl)-l-lysine (CEL), Nε-(carboxymethyl)-l-lysine (CML), Amadori products (APs) and off-flavors. A novel approach was proposed to control the Maillard reaction (MR) in fortified milk: ascorbic acid was encapsulated in a lipid coating and the effects were tested after a lab scale UHT treatment. Encapsulation promoted a delayed release of ascorbic acid and a reduction in the formation of MRPs. Total lysine increased up to 45% in milk with encapsulated ascorbic acid, while reductions in CML, CEL and furosine ranged from 10% to 53% compared with control samples. The effects were also investigated towards the formation of amide-AGEs (advanced glycation end products) by high resolution mass spectrometry (HRMS) revealing that several mechanisms coincide with the MR in the presence of ascorbic acid. PMID:27240727

  9. Safety assessment of Maillard reaction products of chicken bone hydrolysate using Sprague-Dawley rats

    Directory of Open Access Journals (Sweden)

    Jin-Zhi Wang

    2016-03-01

    Full Text Available Background: The Maillard reaction products of chicken bone hydrolysate (MRPB containing 38% protein, which is a derived product from chicken bone, is usually used as a flavor enhancer or food ingredient. In the face of a paucity of reported data regarding the safety profile of controversial Maillard reaction products, the potential health effects of MRPB were evaluated in a subchronic rodent feeding study. Methods: Sprague–Dawley rats (SD, 5/sex/group were administered diets containing 9, 3, 1, or 0% of MRPB derived from chicken bone for 13 weeks. Results: During the 13-week treatment period, no mortality occurred, and no remarkable changes in general condition and behavior were observed. The consumption of MRPB did not have any effect on body weight or feed and water consumption. At the same time, there was no significant increase in the weights of the heart, liver, lung, kidney, spleen, small intestine, and thymus in groups for both sexes. Serological examination showed serum alanine aminotransferase in both sexes was decreased significantly, indicating liver cell protection. No treatment-related histopathological differences were observed between the control and test groups. Conclusion: Based on the results of this study, the addition of 9% MRPB in the diet had no adverse effect on both male and female SD rats during the 90-day observation. Those results would provide useful information on the safety of a meaty flavor enhancer from bone residue as a byproduct of meat industry.

  10. The influence of the concentration of atmospheric radon decay products on the environmental radiation dose rate

    International Nuclear Information System (INIS)

    It has been occasionally found from an area monitoring data obtained at an atomic power station that the daily periodical change of the environmental radiation dose rate appeared near the ground surface. It is suggested that the variation has resulted from the change of atmospheric radon concentration and that it has also depended on the geographical features of the observation point. The change component has been estimated to be up to nearly 30 percent of the environmental radiation dose rate from monitoring data. To investigate precisely the phenomena, observation was performed near a monitoring station and at other area in Fukui Prefecture during the summer. The dose rate from terrestrial radiation was 42 nGy/h at the Natasho in Ooi Town and was 30 nGy/h at the Kaminaka in Wakasa Town. The concentration of radon decay products in the air was 0.5 - 30 Bq/m3 at the Natasho site and was 1 - 10 Bq/m3 at the Kaminaka site. From the concentration of radon decay products in the atmosphere, the dose rate was respectively estimated to be 0-7.0 nGy/h at the Natasho site, and to be 0-5.5 nGy/h at the Kaminaka site. Furthermore, 0.26(nGy/h)/(Bq/m3) and 0.56(nGy/h)/(Bq/m3) were estimated as the dose rate conversion factor of radon concentration in the air at the Natasho site and at the Kaminaka site, respectively. (author)

  11. Application of micro X-ray diffraction to investigate the reaction products formed by the alkali silica reaction in concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Dähn, R.; Arakcheeva, A.; Schaub, Ph.; Pattison, P.; Chapuis, G.; Grolimund, D.; Wieland, E.; Leemann, A. (Ecole); (PSI); (Phase Solutions); (ESRF)

    2015-12-21

    Alkali–silica reaction (ASR) is one of the most important deterioration mechanisms in concrete leading to substantial damages of structures worldwide. Synchrotron-based micro-X-ray diffraction (micro-XRD) was employed to characterize the mineral phases formed in micro-cracks of concrete aggregates as a consequence of ASR. This particular high spatial resolution technique enables to directly gain structural information on ASR products formed in a 40-year old motorway bridge damaged due to ASR. Micro-X-ray-fluorescence was applied on thin sections to locate the reaction products formed in veins within concrete aggregates. Micro-XRD pattern were collected at selected points of interest along a vein by rotating the sample. Rietveld refinement determined the structure of the ASR product consisting of a new layered framework similar to mountainite and rhodesite. Furthermore, it is conceivable that understanding the structure of the ASR product may help developing new technical treatments inhibiting ASR.

  12. In vitro antibacterial analysis of phenoloxidase reaction products from the sea cucumber Apostichopus japonicus.

    Science.gov (United States)

    Jiang, Jingwei; Zhou, Zunchun; Dong, Ying; Cong, Cong; Guan, Xiaoyan; Wang, Bai; Chen, Zhong; Jiang, Bei; Yang, Aifu; Gao, Shan; Sun, Hongjuan

    2014-08-01

    Three phenoloxidases (POs) of Apostichopus japonicus, AjPOs (AjPO1, AjPO2 and AjPO3), were partially purified from the coelomocytes with an electrophoretic method, and then employed for the in vitro antibacterial analysis. Using L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate, AjPO1 and AjPO2-derived compounds inhibited the growth of Vibrio splendidus and Staphylococcus aureus, while AjPO3-derived compounds only inhibited the growth of V. splendidus. When dopamine was used as a substrate, AjPO1 and AjPO3-derived compounds inhibited the growth of V. splendidus and Vibrio harveyi, while AjPO2-derived compounds only inhibited the growth of V. splendidus. Moreover, AjPO1-derived compounds showed stronger inhibition in V. harveyi than AjPO3-derived compounds did. However, all of the three AjPO reaction products showed no inhibitions on the growth of Pseudoalteromonas nigrifaciens, Shewanella baltica, Micrococcus lysodeikticus, Streptococcus dysgalactiae and Nocardiopsis sp. with L-DOPA or dopamine as a substrate. Scanning electron microscope (SEM) observation of V. harveyi treated by AjPOs and dopamine showed that AjPO1-derived compounds resulted in massive bacteriolysis, AjPO2-derived compounds caused no obvious alteration on bacterial morphology, and AjPO3-derived compounds increased the ratio of spheroidal bacteria. All these results suggested that AjPO reaction products derived by L-DOPA and dopamine had different but limited antibacterial spectrum, and the different antibacterial effects observed among three AjPOs resulted from the different reaction products generated by AjPOs with the same substrate. PMID:24931626

  13. Pressure Effects on Product Channels of the Allyl Radical Reactions; C3H5+C3H5 and C3H5+CH3

    Science.gov (United States)

    Halpern, J. B.; N'Doumi, M.; Fahr, A.

    2011-12-01

    Relatively large hydrocarbon molecules (C4, C6 and larger) have been detected in several planetary environments. The mechanism for the formation of such large molecular species and detailed mechanism for their potential destruction are not well understood and are of considerable current interest. Previously we have studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modeling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. Pressure-dependent product yields have been determined experimentally for the self- and cross-radical reactions performed at 298 K and at pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final reaction products were quantitatively determined using a gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the experiments and provided valuable information on the complex reaction mechanisms. Theses studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report recent results for the allyl radical reactions H2CCCH3+ H2CCCH3 and H2CCCH3+CH3. For the allyl radical self-reaction, at high pressures the "head -to-head", combination channel forming 1,5-hexadiene is dominant with a combination/disproportionation = 1,5-hexadiene/propyne ratio of about 24 at 500 Torr (67 kPa, T=298K). At low pressures the ratio is substantially reduced to about 1.2 (at 0.3 kPa) and other major products are observed including allene, propene, 1-butene and propyne.

  14. Organic and inorganic decomposition products from the thermal desorption of atmospheric particles

    Science.gov (United States)

    Williams, Brent J.; Zhang, Yaping; Zuo, Xiaochen; Martinez, Raul E.; Walker, Michael J.; Kreisberg, Nathan M.; Goldstein, Allen H.; Docherty, Kenneth S.; Jimenez, Jose L.

    2016-04-01

    Atmospheric aerosol composition is often analyzed using thermal desorption techniques to evaporate samples and deliver organic or inorganic molecules to various designs of detectors for identification and quantification. The organic aerosol (OA) fraction is composed of thousands of individual compounds, some with nitrogen- and sulfur-containing functionality and, often contains oligomeric material, much of which may be susceptible to decomposition upon heating. Here we analyze thermal decomposition products as measured by a thermal desorption aerosol gas chromatograph (TAG) capable of separating thermal decomposition products from thermally stable molecules. The TAG impacts particles onto a collection and thermal desorption (CTD) cell, and upon completion of sample collection, heats and transfers the sample in a helium flow up to 310 °C. Desorbed molecules are refocused at the head of a gas chromatography column that is held at 45 °C and any volatile decomposition products pass directly through the column and into an electron impact quadrupole mass spectrometer. Analysis of the sample introduction (thermal decomposition) period reveals contributions of NO+ (m/z 30), NO2+ (m/z 46), SO+ (m/z 48), and SO2+ (m/z 64), derived from either inorganic or organic particle-phase nitrate and sulfate. CO2+ (m/z 44) makes up a major component of the decomposition signal, along with smaller contributions from other organic components that vary with the type of aerosol contributing to the signal (e.g., m/z 53, 82 observed here for isoprene-derived secondary OA). All of these ions are important for ambient aerosol analyzed with the aerosol mass spectrometer (AMS), suggesting similarity of the thermal desorption processes in both instruments. Ambient observations of these decomposition products compared to organic, nitrate, and sulfate mass concentrations measured by an AMS reveal good correlation, with improved correlations for OA when compared to the AMS oxygenated OA (OOA

  15. 22Na production cross sections from the 19F(α,n) reaction

    International Nuclear Information System (INIS)

    The thick-target neutron yield from the 19F(α,n) reaction has been measured in 0.25-MeV steps over the energy range 3.5 less than or equal to E/sub α/ less than or equal to 10.0 MeV. From these measurements, 22Na production cross sections have been deduced. These cross sections are compared with the results of a Hauser-Feshbach calculation and with the results of previous experimental investigations. 10 references

  16. Limonene and its ozone-initiated reaction products attenuate allergic lung inflammation in mice

    DEFF Research Database (Denmark)

    Hansen, Jitka S; Nørgaard, Asger W; Koponen, Ismo K;

    2016-01-01

    and pulmonary irritation was investigated in addition to ovalbumin-specific antibodies, inflammatory cells, total protein and surfactant protein D in bronchoalveolar lavage fluid and hemeoxygenase-1 and cytokines in lung tissue. Overall, airway allergy was not exacerbated by any of the exposures. In contrast...... showed that irritation responses might be modulated by airway allergy. However, aggravation of allergic symptoms was observed by neither exposure to ozone nor exposure to ozone-initiated limonene reaction products. In contrast, anti-inflammatory properties of the tested limonene-containing pollutants...... might attenuate airway allergy....

  17. Diffractive $\\Lambda_{c}^{+}$ Productions in Polarized p p Reactions and Polarized Gluon Distribution

    CERN Document Server

    Kochelev, N I; Oyama, S

    2001-01-01

    To test the model of the polarized gluon distribution $\\Delta G(x, Q^2)$ in the proton, we propose a new process, diffractive $\\Lambda_c^+$ productions in polarized $pp$ reactions, which will be observed in the forthcoming RHIC and also the proposed HERA-$\\vec {\\rm N}$ experiments. The spin correlation between the target proton and the $\\Lambda_c^+$ produced in the target fragmentation region largely depends on $\\Delta G(x, Q^2)$ and thus, the process is quite promising for testing the models of $\\Delta G(x, Q^2)$.

  18. Reaction mechanisms and production of exotic nuclei using 200 MeV/n 40Ar

    International Nuclear Information System (INIS)

    Experiments using the fragmentation of 40Ar at 200 MeV/n have proved to be a powerful new tool for the investigation of both the dynamics of nuclear interactions at high energies and the limits of nuclear stability. In order to study the reaction mechanism, C and Th targets were bombarded by 213 MeV/n 40Ar. Energy spectra were measured at lab angles from 00 to 40 in a telescope. Isotope production cross sections were obtained by integrating the energy spectra and angular distributions. (orig./AH)

  19. Production of terbium-152 by heavy ion reactions and proton induced spallation

    International Nuclear Information System (INIS)

    Terbium-152 (Tb-152) is of potential value as a radiotracer for radiolanthanides in positron emission tomography. We report the production of Tb-152 by heavy ion reactions at the ANU Tandem accelerator, and by the spallation method at the CERN proton accelerator using the on-line ISOLDE separator, obtaining microcurie and millicurie yields, respectively. After purification, a phantom image in PET is obtained which shows the feasibility of using Tb-152 for monitoring the kinetics of Tb-149 and other radiolanthanides. However, the current availability of this radioisotope will be restricted to major nuclear physics research centres

  20. Production of terbium-152 by heavy ion reactions and proton induced spallation

    CERN Document Server

    Allen, B J; Sarkar, S; Beyer, G; Morel, Christian; Byrne, A P

    2001-01-01

    Terbium-152 (Tb-152) is of potential value as a radiotracer for radiolanthanides in positron emission tomography. We report the production of Tb-152 by heavy ion reactions at the ANU Tandem accelerator, and by the spallation method at the CERN proton accelerator using the on-line ISOLDE separator, obtaining microcurie and millicurie yields, respectively. After purification, a phantom image in PET is obtained which shows the feasibility of using Tb-152 for monitoring the kinetics of Tb-149 and other radiolanthanides. However, the current availability of this radioisotope will be restricted to major nuclear physics research centres. (7 refs).

  1. Effect of entrance channel parameters on the fusion of two heavy ions: Excitation functions of reaction products in 16O+66Zn and 37Cl + 45Sc reactions

    Indian Academy of Sciences (India)

    Suparne Sodaye; B S Tomar; A Goswami

    2006-06-01

    Excitation functions of reaction products formed in 16O+66Zn and 37Cl + 45Sc systems, leading to the same compound nucleus, 82Sr, were measured using recoilcatcher technique and off-line -ray spectrometry. The contribution of non-compound processes like transfer and incomplete fusion (ICF) reactions to the cross-sections of different evaporation residues were delineated by comparing the experimental data with the predictions of Monte Carlo simulation code PACE2. The results show that non-compound processes become a significant fraction of the total reaction cross-section in 16O+66Zn systems in the beam energy range studied, while 37Cl + 45Sc gives mainly compound nucleus products. The mass asymmetry dependence of the fusion and non-compound cross-sections have been analysed in terms of the static fusion model and sum rule model.

  2. Stable Hydrogen Production from Ethanol through Steam Reforming Reaction over Nickel-Containing Smectite-Derived Catalyst

    OpenAIRE

    Hiroshi Yoshida; Ryohei Yamaoka; Masahiko Arai

    2014-01-01

    Hydrogen production through steam reforming of ethanol was investigated with conventional supported nickel catalysts and a Ni-containing smectite-derived catalyst. The former is initially active, but significant catalyst deactivation occurs during the reaction due to carbon deposition. Side reactions of the decomposition of CO and CH4 are the main reason for the catalyst deactivation, and these reactions can relatively be suppressed by the use of the Ni-containing smectite. The Ni-containing ...

  3. Production of diacylglycerols from glycerol monooleate and ethyl oleate through free and immobilized lipase-catalyzed consecutive reactions.

    Science.gov (United States)

    Jin, Juan; Li, Dan; Zhu, Xue Mei; Adhikari, Prakash; Lee, Ki-Teak; Lee, Jeung-Hee

    2011-02-28

    The ability of free and immobilized lipase on the production of diacylglycerols (DAG) by transesterification of glycerol monooleate (GMO) and ethyl oleate was investigated. Among three free lipases such as lipase G (Penicillium cyclopium), lipase AK (Pseudomonas fluorescens) and lipase PS (Pseudomonas cepacia), lipase PS exhibited the highest DAG productivity, and the DAG content gradually increased up to 24 hours reaction and then remained steady. The comparative result for DAG productivity between free lipase PS and immobilized lipases (lipase PS-D and Lipozyme RM IM) during nine times of 24 hours reaction indicated that total DAG production was higher in immobilized lipase PS-D (183.5mM) and Lipozyme RM IM (309.5mM) than free lipase PS (122.0mM) at the first reaction, and that the DAG production rate was reduced by consecutive reactions, in which more sn-1,3-DAG was synthesized than sn-1,2-DAG. During the consecutive reactions, the activity of lipase PS was relatively steady by showing similar DAG content, whereas DAG production of lipase PS-D and Lipozyme RM IM was gradually decreased to 69.9 and 167.1mM at 9th reaction, respectively, resulting in 62% and 46% reduced production when compared with 1st reaction. Interestingly, from 7th reaction lipase PS produced more DAG than immobilized lipase PS-D, and exhibited a stable activity for DAG production. Therefore, the present study suggested that DAG productivity between GMO and ethyl oleate was higher in immobilized lipases than free lipases, but the activity was reduced with repeated uses. PMID:20951847

  4. Catalytic hydrogen production from fossil fuels via the water gas shift reaction

    International Nuclear Information System (INIS)

    Highlights: • Hydrogen is a clean alternative to hydrocarbon fuels. • Hydrogen is primarily produced with the water gas shift reaction. • Development of water gas shift catalysts is essential to the energy industry. • This work summarizes recent progress in water gas shift catalyst research. - Abstract: The production of hydrogen is a highly researched topic for many reasons. First of all, it is a clean fuel that can be used instead of hydrocarbons, which produce CO2, a greenhouse gas emission that is thought to be the reason for climate change in the world. The largest source of hydrogen is the water gas shift (WGS) reaction, where CO and water are mixed over a catalyst to produce the desired hydrogen. Many researchers have focused on development of WGS catalysts with different metals. The most notable of these metals are precious and rare earth metals which, when combined, have unique properties for the WGS reaction. Research in this area is very important to the energy industry and the future of energy around the world. However, the progress made recently has not been reviewed, and this review was designed to fill the gap

  5. Some results of the production of long-lived radionuclides in fast neutron induced reactions

    International Nuclear Information System (INIS)

    High purity C, Al, KHCO3, Zn, Cu, Ni, Mo, Si3N4 and SiO2 samples were irradiated with 14.6 MeV neutrons in Debrecen to produce long-lived radionuclides in fast neutron induced reactions. The determinations of the reaction products are in progress by using either the radiochemical separation method or the classical and accelerator mass spectrometry in collaboration with Juelich KFA, Cologne and Hannover Universities. Cross section curves were measured for the 151Eu(n,2n)150mEu and 159Tb(n,2n)158Tb reactions in 8.7 - 10.7 MeV range in co-operation between Juelich and Debrecen. Properties of cyclotron D-D neutron sources were studied and improved to increase the precision of the cross section measurements. In addition, the combination of the threshold detector and the physical integration methods rendered it possible to determine the volume averaged flux density spectra for extended samples. (author). 7 refs, 5 figs, 3 tabs

  6. Excitation of the reaction of 123I, 123Xe and 123Cs radionuclides production

    International Nuclear Information System (INIS)

    The results of calculations of charged particle induced reactions for the production of radioisotopes 123I, 123Cs, 123Xe are discussed. The excitation functions for reactions 124Xe(p,2n), 124Xe(d,3n), 124Xe(p,pn+np), 127I(p,5n), 124Xe(d,p2n), 123Te(p,n), 124Te(p,2n), 121Sb(α,2n)123I are calculated on the base of statistical model in energy range up to 80 MeV. The agreement between the calculations and experiment is reasonable as a rule. It is shown, that taking account of the radiative channel is very important near threshold, particularly for neutron deficient nuclei. The analysis performed showed that the calculations with code ALICE can serve as a reasonable evaluation for the excitation functions of various reactions, if they are tested by experiment and by comparison of relevant computer codes. 55 refs.; 9 figs.; 10 tabs

  7. 40 CFR 721.3830 - Formaldehyde, reaction products with an alkylated phenol and an aliphatic amine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3830 Formaldehyde, reaction... new uses subject to reporting. (1) The chemical substance identified generically as...

  8. Characterization of hypersensitivity reactions reported among Andrographis paniculata users in Thailand using Health Product Vigilance Center (HPVC) database

    OpenAIRE

    Suwankesawong, Wimon; Saokaew, Surasak; Permsuwan, Unchalee; Chaiyakunapruk, Nathorn

    2014-01-01

    Background Andrographis paniculata (andrographis) is one of the herbal products that are widely used for various indications. Hypersensitivity reactions have been reported among subjects receiving Andrographis paniculata in Thailand. Understanding of characteristics of patients, adverse events, and clinical outcomes is essential for ensuring population safety. This study aimed to describe the characteristics of hypersensitivity reactions reported in patients receiving andrographis containing ...

  9. Operando magnetic resonance: monitoring the evolution of conversion and product distribution during the heterogeneous catalytic ethene oligomerisation reaction.

    Science.gov (United States)

    Roberts, S Tegan; Renshaw, Matthew P; Lutecki, Michal; McGregor, James; Sederman, Andrew J; Mantle, Mick D; Gladden, Lynn F

    2013-11-18

    Operando magnetic resonance (MR) spectroscopy has been used to follow an ethene oligomerisation reaction performed at 110 °C, 28 barg over a 1 wt% Ni/SiO2-Al2O3 catalyst. Spectra acquired over the timecourse of the reaction allow the calculation of conversion and product distribution as a function of time-on-stream. PMID:24088715

  10. pH-Controlled Oxidation of an Aromatic Ketone: Structural Elucidation of the Products of Two Green Chemical Reactions

    Science.gov (United States)

    Ballard, C. Eric

    2010-01-01

    A laboratory experiment emphasizing the structural elucidation of organic compounds has been developed as a discovery exercise. The "unknown" compounds are the products of the pH-controlled oxidation of 4'-methoxyacetophenone with bleach. The chemoselectivity of this reaction is highly dependent on the pH of the reaction media: under basic…

  11. Production of a covalent flavin linkage in lipoamide dehydrogenase. Reaction with 8-Cl-FAD.

    Science.gov (United States)

    Moore, E G; Cardemil, E; Massey, V

    1978-09-25

    A method is described for preparation of apolipoamide dehydrogenase which gives quantitative removal of FAD. Active holoenzyme can be reconstituted by incubation with FAD. Reconstitution of apoenzyme with 8-Cl-FAD results in the fixation of most of the flavin to the protein in a covalently bound form. The portion noncovalently bound was shown to be unmodified 8-Cl-FAD. The covalently bound flavin has an absorption spectrum quite different from that of 8-Cl-FAD. It has a single band in the visible with a maximum at 459 nm (extinction coefficient of 22 mM-1 cm-1) and a shoulder at 480 nm. Model reactions between 8-Cl-Flavin (riboflavin or FAD) and organic thiols (thiophenol, beta-mercaptoethanol, or N-acetylcysteine) give products with spectra which are similar to that of FAD covalently bound to lipoamide dehydrogenase. The products of the model reactions have a single visible band with a maximum at 480 nm (extinction coefficient of 23.6 mM-1 cm-1 to 28.4 mM-1 cm-1) and a shoulder at 460 nm. The products of the model reaction and the covalently bound FAD of lipoamide dehydrogenase appear to be the result of a nucleophilic attack on the carbon at position 8 of the flavin ring by a thiolate anion, displacing the chloride. Thus, the product of the model reaction is 8-(RS)-flavin, and the product of the reaction between 8-Cl-FAD and protein probably has a cysteinyl residue covalently attacked at position 8 of FAD. Reconstitution of apoliopoamide dehydrogenase with 8-Cl-FAD gives two enzyme products which are fractionated by ammonium sulfate. Enzyme fractionating between 20% and 45% ammonium sulfate is monomeric and contains covanently bound FAD. Enzyme fractionating between 55% and 75% ammonium sulfate is dimeric and contains both covalently bound FAD and noncovalently bound 8-Cl-FAD. Both protein fractions contain one FAD per protein subunit and both are active with physiological substrates with Km values for NAD and dihydrolipoamide similar to those of native lipoamide

  12. Measurement of the Residual Gases O2 and CO2 in Meat Products Packed in Modified Atmosphere

    Directory of Open Access Journals (Sweden)

    Jozef Čapla

    2013-02-01

    Full Text Available Nowadays, consumers have increased demand for quality and food safety and also rising demand for natural foods without chemical additives. There are many ways to presserve freshness of these products, one of them is modified atmosphere packaging, which can mean elimination and/or replacement surrounding the product before closing it in package with a mixture of gases other than the original ambient air atmosphere. for replacement of atmosphere are generally used three types of gases such as carbon dioxide, oxygen and nitrogen. this type of packaging is often used for meat and meat products, which belongs to foods that are under normal conditions perishable and for increasing the shelf life of meat products are also used various other preservation methods or their combinations. Packaging of meat and meat products in modified atmosphere is usually made with a high content of carbon dioxide, which has good bacteriostatic and fungistatic effect and is also an effective mean for increasing the shelf life of packaged products during storage and sale.

  13. Hydrogen production reaction with a metal oxide catalyst in high pressure high temperature water

    International Nuclear Information System (INIS)

    Hydrogen production from biomass was attempted in high pressure high temperature water at 573 K by adopting partial oxidation to increase the yield of H2 via CO production in the presence of ZnO. The results revealed that an addition of H2O2 as an oxidant to the reaction of glucose and sugarcane bagasse brought about the trend of increasing the yields of H2, CO, and CO2. However, the sensitivity of H2 yield on H2O2 amount was different from those of CO and CO2, namely the excess amount of H2O2 tends to decrease the H2 yield with giving a maximum at a certain H2O2 amount. These indicated that the controllability of partial oxidation would be a key factor for maximizing the H2 yield through biomass conversion by partial oxidative gasification in high pressure high temperature water

  14. Oxidation Products of Biogenic Emissions Contribute to Nucleation of Atmospheric Particles

    OpenAIRE

    Riccobono, F.; Schobesberger, S.; Scott, CE; Dommen, J; Ortega, IK; L. Rondo; Almeida, J; Amorim, A.; BIANCHI, F.; Breitenlechner, M.; David, A.(CERN, European Organization for Nuclear Research, Geneva, Switzerland); Downard, A.; Dunne, EM; J. Duplissy; S. Ehrhart

    2014-01-01

    Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in ...

  15. Study of the corrosion products formed on carbon steels in the tropical atmosphere of Panama

    Directory of Open Access Journals (Sweden)

    Jaén, J. A.

    2003-12-01

    Full Text Available Mössbauer spectroscopy and X-ray powder diffraction (in selected samples have been used to characterize corrosion products on carbon steels after atmospheric exposure to the tropical Panamanian locations of Panama and Colon, classified according to ISO 9223 as C3 and C5, respectively. Goethite (α-FeOOH of intermediate particle size (20-100 nm, lepidocrocite (γ-FeOOH, a spinel phase consisting of non-stoichiometric magnetite (Fe3-xO4 and/or maghemite (γ-Fe2O3 and nano-sized particles were identified in the corrosion products. The spinel phase is related to short term atmospheric exposure transforms in time to other corrosion products. The corrosion resistance increased with fraction of goethite following a saturation-type behavior.

    Se caracterizaron los productos de corrosión de aceros al carbono expuestos a las atmósferas tropicales panameñas localizadas en Panamá y Colón, mediante el uso de la espectroscopia Mössbauer y difracción de rayos-X (en muestras seleccionadas. Las atmósferas se clasifican como C3 y C5, respectivamente, de acuerdo a la norma ISO 9223. Se lograron identificar los compuestos goethita (α-FeOOH de tamaño de partícula intermedio (20-100 nm, lepidocrocita (γ-FeOOH, una fase de espinela consistente en magnetita no estequiométrica (Fe3-xO4 y/o maghemita (γ-Fe2O3, y nanopartículas. La fase de espinela se puede correlacionar con exposiciones cortas a la atmósfera, transformándose en el tiempo en otros productos de corrosión. La resistencia a la corrosión se incrementa con la cantidad de goethita siguiendo una conducta de saturación.

  16. Evaluation of tissue reaction, cell viability and cytokine production induced by Sealapex Plus

    Directory of Open Access Journals (Sweden)

    João Eduardo Gomes-Filho

    2011-08-01

    Full Text Available OBJECTIVE: The aim of this study was to investigate the effects of mineral trioxide aggregate (MTA, Sealapex, and a combination of Sealapex and MTA (Sealapex Plus on the reaction of subcutaneous connective tissue of rats, and on cell viability and cytokine production in mouse fibroblasts. MATERIAL AND METHODS: The tissue reaction was carried out with dentin tubes containing the materials implanted in the dorsal connective tissue of rats. The histological analysis was performed after 7 and 30 days. Millipore culture plate inserts with polyethylene tubes filled with materials were placed into 24-well cell culture plates with mouse fibroblasts to evaluate the cell viability by MTT assay. ELISA assays were also performed after 24 h of exposure of the mouse fibroblasts to set material disks. RESULTS: Histopathologic examination showed Von Kossa-positive granules that were birefringent to polarized light for all the studied materials at the tube openings. No material inhibited the cell viability in the in vitro test. It was detected IL-6 production in all root-end filling materials. MTA and Sealapex Plus induced a slight raise of mean levels of IL-1β. CONCLUSIONS: The results suggest that Sealapex Plus is biocompatible and stimulates the mineralization of the tissue.

  17. Insulin and leptin enhance human sperm motility, acrosome reaction and nitric oxide production

    Institute of Scientific and Technical Information of China (English)

    Fanuel Lampiao; Stefan S. du Plessis

    2008-01-01

    Aim: To investigate the in vitro effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide (NO) production. Methods: Washed human spermatozoa from normozoospermic donors were treated with insulin (10 μIU) and leptin (10 nmol). Insulin and leptin effects were blocked by inhibition of their intracellular effector, phosphotidylinositol 3-kinase (PI3K), by wortmannin (10 μmol) 30 min prior to insulin and leptin being given. Computer-assisted semen analysis was used to assess motility after 1, 2 and 3 h of incubation. Viability was assessed by fluorescence-activated cell sorting using propidium iodide as a fluorescent probe. Acrosome-reacted cells were observed under a fluorescent microscope using fluorescein-isothiocyanate-Pisum sativum agglutinin as a probe. NO was measured after treating the sperm with 4,5-diaminofluorescein-2/diacetate (DAF-2/DA) and analyzed by fluorescence-activated cell sorting. Results: Insulin and leptin significantly increased total motility, progressive motility and acrosome reaction, as well as NO production. Conclusion: This study showed the in vitro beneficial effects of insulin and leptin on human sperm function. These hormones could play a role in enhancing the fertilization capacity of human spermatozoa.

  18. Simultaneous measurement of deuterium distribution and impurities by emission angle analysis of deuteron induced reaction products

    CERN Document Server

    Kubota, N; Furuyama, Y; Kitamura, A

    2002-01-01

    A novel analytical method of light element distribution in a thin film is presented. The method is based on the deuteron-induced nuclear reaction. The emission angle of the lighter product detected coincidentally with the heavier product is analyzed to deduce the depth distribution of the target atoms, while the conventional energy analysis is applied for impurities, the distributions of which are not of primary interest. Results of proof-of-principle experiments using the D(d,p)t reaction for a deuterated polyethylene (C sub 2 D sub 4) film are described. The depth resolution is evaluated to be 0.66+-0.07 mu m for 400 keV deuteron incidence in the C sub 2 D sub 4 film. Factors limiting the resolution are discussed, and possible improvement even down to several tens of nm is concluded. The present method is applicable for microanalysis of some light elements other than deuterium contained in a film with thickness of several mu m which cannot be reached by conventional heavy ion elastic recoil detection using ...

  19. Tests of a large air-core superconducting solenoid as a nuclear-reaction-product spectrometer

    International Nuclear Information System (INIS)

    An air-core superconducting solenoid, with a diameter of 0.2 m and a length of 0.4 m, has been configured for use as a heavy-ion reaction-product spectrometer (E/A≤5 MeV/u) near θ = 0 0. The spectrometer has a large solid angle (10--35 msr) and properties suitable for time-of-flight measurements with flight paths approx. > 2 m. The performance of the spectrometer was established using α-particle sources and nuclear-reaction products from heavy-ion collisions. The characteristics of air-core magnets are compared to those of steel-yoke magnets. The simplicity and ease of operation of the air-core magnet, without significant problems from the (axial) fringe fields, suggests that larger air-core magnets with dΩ≥20 msr and capable of focusing ions with E/A≥30 MeV/u are feasible. Other applications of solenoids and combinations of solenoids with radial electric-field lenses (ELCO lenses) are also discussed, including designs which focus more than one charge state simultaneously

  20. Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems

    Energy Technology Data Exchange (ETDEWEB)

    Hafsteinsdottir, Erla G., E-mail: erla.hafsteinsdottir@gmail.com [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); White, Duanne A., E-mail: duanne.white@mq.edu.au [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); Gore, Damian B., E-mail: damian.gore@mq.edu.au [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); Stark, Scott C., E-mail: scott.stark@aad.gov.au [Environmental Protection and Change, Australian Antarctic Division, Department of Sustainability, Environment, Water, Population and Communities, Tasmania 7050 (Australia)

    2011-12-15

    Orthophosphate fixation of metal contaminated soils in environments that undergo freeze-thaw cycles is understudied. Freeze-thaw cycling potentially influences the reaction rate, mineral chemical stability and physical breakdown of particles during fixation. This study determines what products form when phosphate (triple superphosphate [Ca(H{sub 2}PO{sub 4}){sub 2}] or sodium phosphate [Na{sub 3}PO{sub 4}]) reacts with lead (PbSO{sub 4} or PbCl{sub 2}) in simple chemical systems in vitro, and assesses potential changes in formation during freeze-thaw cycles. Systems were subjected to multiple freeze-thaw cycles from +10 deg. C to -20 deg. C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freeze-thaw cycles. Low temperature lead orthophosphate reaction efficiency varied according to both phosphate and lead source; the most time-efficient pyromorphite formation was observed when PbSO{sub 4} and Na{sub 3}PO{sub 4} were present together. These findings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate. - Highlights: > Formation of lead phosphate products in cold environments is identified. > Potential change in formation during freeze-thaw cycling is assessed. > Lead phosphate reaction efficiency varies according to phosphate and lead source. > Pyromorphite formation is stable during 240 freeze-thaw cycles. - Pyromorphite, formed from Pb phosphate fixation, is stable during multiple freeze-thaw cycles but the efficiency of the fixation depends on the phosphate source and the type of Pb mineral.