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Sample records for mixed acid oxidation

  1. Selective oxidation of propane to acrylic acid over mixed metal oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    Wei Zheng; Zhenxing Yu; Ping Zhang; Yuhang Zhang; Hongying Fu; Xiaoli Zhang; Qiquan Sun; Xinguo Hu

    2008-01-01

    The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic perfor-mances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio (Mo1 V0.31Te0.23Nb0.12). The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H81 :O2 : H2O : N1 = 4.4 : 12.8 : 15.3 : 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.

  2. Effects of calcination temperature and acid-base properties on mixed potential ammonia sensors modified by metal oxides.

    Science.gov (United States)

    Satsuma, Atsushi; Katagiri, Makoto; Kakimoto, Shiro; Sugaya, Satoshi; Shimizu, Kenichi

    2011-01-01

    Mixed potential sensors were fabriated using yttria-stabilized zirconia (YSZ) as a solid electrolyte and a mixture of Au and various metal oxides as a sensing electrode. The effects of calcination temperature ranging from 600 to 1,000 °C and acid-base properties of the metal oxides on the sensing properties were examined. The selective sensing of ammonia was achieved by modification of the sensing electrode using MoO(3), Bi(2)O(3) and V(2)O(5), while the use of WO(3,) Nb(2)O(5) and MgO was not effective. The melting points of the former group were below 820 °C, while those of the latter group were higher than 1,000 °C. Among the former group, the selective sensing of ammonia was strongly dependent on the calcination temperature, which was optimum around melting point of the corresponding metal oxides. The good spreading of the metal oxides on the electrode is suggested to be one of the important factors. In the former group, the relative response of ammonia to propene was in the order of MoO(3) > Bi(2)O(3) > V(2)O(5), which agreed well with the acidity of the metal oxides. The importance of the acidic properties of metal oxides for ammonia sensing was clarified.

  3. Effects of Calcination Temperature and Acid-Base Properties on Mixed Potential Ammonia Sensors Modified by Metal Oxides

    Directory of Open Access Journals (Sweden)

    Kenichi Shimizu

    2011-02-01

    Full Text Available Mixed potential sensors were fabriated using yttria-stabilized zirconia (YSZ as a solid electrolyte and a mixture of Au and various metal oxides as a sensing electrode. The effects of calcination temperature ranging from 600 to 1,000 °C and acid-base properties of the metal oxides on the sensing properties were examined. The selective sensing of ammonia was achieved by modification of the sensing electrode using MoO3, Bi2O3 and V2O5, while the use of WO3, Nb2O5 and MgO was not effective. The melting points of the former group were below 820 °C, while those of the latter group were higher than 1,000 °C. Among the former group, the selective sensing of ammonia was strongly dependent on the calcination temperature, which was optimum around melting point of the corresponding metal oxides. The good spreading of the metal oxides on the electrode is suggested to be one of the important factors. In the former group, the relative response of ammonia to propene was in the order of MoO3 > Bi2O3 > V2O5, which agreed well with the acidity of the metal oxides. The importance of the acidic properties of metal oxides for ammonia sensing was clarified.

  4. Effects of Calcination Temperature and Acid-Base Properties on Mixed Potential Ammonia Sensors Modified by Metal Oxides

    Science.gov (United States)

    Satsuma, Atsushi; Katagiri, Makoto; Kakimoto, Shiro; Sugaya, Satoshi; Shimizu, Kenichi

    2011-01-01

    Mixed potential sensors were fabriated using yttria-stabilized zirconia (YSZ) as a solid electrolyte and a mixture of Au and various metal oxides as a sensing electrode. The effects of calcination temperature ranging from 600 to 1,000 °C and acid-base properties of the metal oxides on the sensing properties were examined. The selective sensing of ammonia was achieved by modification of the sensing electrode using MoO3, Bi2O3 and V2O5, while the use of WO3, Nb2O5 and MgO was not effective. The melting points of the former group were below 820 °C, while those of the latter group were higher than 1,000 °C. Among the former group, the selective sensing of ammonia was strongly dependent on the calcination temperature, which was optimum around melting point of the corresponding metal oxides. The good spreading of the metal oxides on the electrode is suggested to be one of the important factors. In the former group, the relative response of ammonia to propene was in the order of MoO3 > Bi2O3 > V2O5, which agreed well with the acidity of the metal oxides. The importance of the acidic properties of metal oxides for ammonia sensing was clarified. PMID:22319402

  5. Au-supported Pt-Au mixed atomic monolayer electrocatalyst with ultrahigh specific activity for oxidation of formic acid in acidic solution.

    Science.gov (United States)

    Huang, Zhao; Liu, Yan; Xie, Fangyun; Fu, Yingchun; He, Yong; Ma, Ming; Xie, Qingji; Yao, Shouzhuo

    2012-12-25

    Au-supported Pt-Au mixed atomic monolayer electrocatalyst was prepared by underpotential deposition of Cu on Au and then redox replacement with noble metal atoms, which shows an ultrahigh Pt-mass (or Pt-area) normalized specific electrocatalytic activity of 102 mA μg(Pt)(-1) (124 mA cm(Pt)(-2)) for oxidation of formic acid in acidic aqueous solution.

  6. Decolourisation of Acid Orange 7 recalcitrant auto-oxidation coloured by-products using an acclimatised mixed bacterial culture.

    Science.gov (United States)

    Bay, Hui Han; Lim, Chi Kim; Kee, Thuan Chien; Ware, Ismail; Chan, Giek Far; Shahir, Shafinaz; Ibrahim, Zaharah

    2014-03-01

    This study focuses on the biodegradation of recalcitrant, coloured compounds resulting from auto-oxidation of Acid Orange 7 (AO7) in a sequential facultative anaerobic-aerobic treatment system. A novel mixed bacterial culture, BAC-ZS, consisting of Brevibacillus panacihumi strain ZB1, Lysinibacillus fusiformis strain ZB2, and Enterococcus faecalis strain ZL bacteria were isolated from environmental samples. The acclimatisation of the mixed culture was carried out in an AO7 decolourised solution. The acclimatised mixed culture showed 98 % decolourisation within 2 h of facultative anaerobic treatment using yeast extract and glucose as co-substrate. Subsequent aerobic post treatment caused auto-oxidation reaction forming dark coloured compounds that reduced the percentage decolourisation to 73 %. Interestingly, further agitations of the mixed culture in the solution over a period of 48 h significantly decolourise the coloured compounds and increased the decolourisation percentage to 90 %. Analyses of the degradation compounds using UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC) showed complete degradation of recalcitrant AO7 by the novel BAC-ZS. Phytotoxicity tests using Cucumis sativus confirmed the dye solution after post aerobic treatment were less toxic compared to the parent dye. The quantitative real-time PCR revealed that E. faecalis strain ZL was the dominant strain in the acclimatised mix culture.

  7. Antimony (V) Oxide Adsorbed on a Silica-Zirconia Mixed Oxide Obtained by the Sol-Gel Processing Method: Preparation and Acid Properties

    OpenAIRE

    Zaitseva,Galina; Gushikem,Yoshitaka

    2002-01-01

    The preparation, degree of dispersion, thermal stability and Lewis and Brønsted acidity of antimony (V) oxide adsorbed on SiO2/ZrO2 mixed oxide, previously prepared by the sol-gel processing method, are described herein. The samples SiO2/ZrO2/Sb2O5, with compositions (in wt %): (a) Zr= 8.1 and Sb= 6.3; (b) Zr= 14.9 and Sb= 11.4, were prepared. Scanning electron microscopy images connected to a X-ray energy dispersive spectrometer showed that both metals, Zr and Sb, were highly dispersed ...

  8. An X-ray photoelectron spectroscopy study of the acidity of SiO{sub 2}-ZrO{sub 2} mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bosman, H.J.M.; Pijpers, A.P.; Jaspers, A.W.M.A. [DSM Research B.V., MD Geleen (Netherlands)

    1996-07-01

    X-ray photoelectron spectroscopy (XPS) of SiO{sub 2}-ZrO{sub 2} mixed oxides was studied. Surface acidity was investigated in light of the relationship between acidity and catalytic effects. 28 refs., 12 figs., 3 tabs.

  9. Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell.

    Science.gov (United States)

    Karayianni, Maria; Gancheva, Valeria; Pispas, Stergios; Petrov, Petar

    2016-03-10

    The electrostatic complexation between lysozyme and stabilized polymeric micelles (SPMs) with a poly(acrylic acid) (PAA) or a mixed poly(ethylene oxide)/poly(acrylic acid) (PEO/PAA) shell (SPMs with a mixed shell, SPMMS) and a temperature-responsive poly(propylene oxide) (PPO) core was investigated by means of dynamic, static, and electrophoretic light scattering. The SPMs and different types of SPMMS used resulted from the self-assembly of PAA-PPO-PAA triblock copolymer chains, or PAA-PPO-PAA and PEO-PPO-PEO triblock copolymer chain mixtures (with varying chain lengths and molar ratios) in aqueous solutions at pH 10 and the subsequent cross-linking of their PPO cores via loading and photo-cross-linking of pentaerythritol tetraacrylate (PETA). The solution behavior, structure and properties of the formed complexes at pH 7 and 0.01 M ionic strength, were studied as a function of the protein concentration in the solution (the concentration of the stabilized micelles was kept constant) or equivalently the ratio of the two components. The complexation process and properties of the complexes proved to be dependent on the protein concentration, while of particular interest was the effect of the structure of the shell of the SPMs on the stability/solubility of the complexes. Finally, the fluorescence and mid infrared spectroscopic investigation of the structure of the complexed protein showed that, although a small stretching of the protein molecules occurred in some cases, no protein denaturation takes place upon complexation.

  10. Fabrication process for sintered mixed oxides soluble in nitric acid from nitrate solutions. [nuclear fuels]. Procede d'obtention d'oxydes mixtes frittes solubles dans l'acide nitrique a partir de solutions de nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Bachelard, R.; Germanaz, P.

    1987-10-02

    Mixed oxide nuclear fuels are obtained by mixing the nitrate solutions, concentration, heat treatment for an intermediary mixed oxide containing U(VI) and Pu(IV or VI), calcination to obtain U/sub 3/O/sub 8/, reduction in U(IV) and Pu(IV), pelletizing, sintering and machining. Less wastes are produced and the fuel pellets are soluble in nitric acid.

  11. Preparation of uniform mixed metal oxide and superconductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Barder, T.J.

    1991-04-30

    This paper describes a method for producing a uniform mixed metal oxide. It includes dissolving metals as their salts of a carboxylic acid in an aliphatic alcohol in the substantial absence of water, the metals are in the same proportions as in the corresponding mixed metal oxide; co-precipitating the metals as their oxalates by mixing the alcohol solution with oxalic acid; separating the co-precipitated metal oxalates and calcining the oxalates in air or oxygen above about 500{degrees} C to convert the oxalates to the corresponding metal oxides.

  12. Aerosol synthesis and electrochemical analysis of niobium mixed-metal oxides for the ethanol oxidation reaction in acid and alkaline electrolyte

    Science.gov (United States)

    Konopka, Daniel A.

    Direct ethanol fuel cells are especially important among emerging electrochemical power systems with the potential to offset a great deal of the energy demand currently met through the use of fossil fuels. Ethanol can be refined from petroleum sources or attained from renewable biomass, and is more easily and safely stored and transported than hydrogen, methanol or gasoline. The full energy potential of ethanol in fuel cells can only be realized if the reaction follows a total oxidation pathway to produce CO2. This must be achieved by the development of advanced catalysts that are electrically conductive, stable in corrosive environments, contain a high surface area on which the reaction can occur, and exhibit a bi-functional effect for the ethanol oxidation reaction (EOR). The latter criterion is achievable in mixed-metal systems. Platinum is an effective metal for catalyzing surface reactions of many adsorbates and is usually implemented in the form of Pt nanoparticles supported on inexpensive carbon. This carbon is believed to be neutral in the catalysis of Pt. Instead, carbon can be replaced with carefully designed metals and metal oxides as co-catalysis or support structures that favorably alter the electronic structure of Pt slightly through a strong metal support interaction, while also acting as an oxygen source near adsorbates to facilitate the total oxidation pathway. Niobium mixed-metal-oxides were explored in this study as bi-functional catalyst supports to Pt nanoparticles. We developed a thermal aerosol synthesis process by which mesoporous powders of mixed-metal-oxides decorated with Pt nanoparticles could be obtained from liquid precursors within ˜5 seconds or less, followed by carefully refined chemical and thermal post-treatments. Exceptionally high surface areas of 170--180m2/g were achieved via a surfactant-templated 3D wormhole-type porosity, comparable on a per volume basis to commercial carbon blacks and high surface area silica supports

  13. Studies of dissolution solutions of ruthenium metal, oxide and mixed compounds in nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Mousset, F.; Eysseric, C.; Bedioui, F

    2004-07-01

    Ruthenium is one of the fission products generated by irradiated nuclear fuel. It is present throughout all the steps of nuclear fuel reprocessing-particularly during extraction-and requires special attention due to its complex chemistry and high {beta}{gamma} activity. An innovative electro-volatilization process is now being developed to take advantage of the volatility of RuO{sub 4} in order to eliminate it at the head end of the Purex process and thus reduce the number of extraction cycles. Although the process operates successfully with synthetic nitrato-RuNO{sup 3+} solutions, difficulties have been encountered in extrapolating it to real-like dissolution solutions. In order to better approximate the chemical forms of ruthenium found in fuel dissolution solutions, kinetic and speciation studies on dissolved species were undertaken with RuO{sub 2},xH{sub 2}O and Ru{sup 0} in nitric acid media. (authors)

  14. Preparation of La-Mo-V mixed-oxide systems and their application in the direct synthesis of acetic acid

    Institute of Scientific and Technical Information of China (English)

    Hamid Reza Arandiyan; Matin Parvari

    2008-01-01

    In this study,mixed metal oxides developed with a perovskite-type structure that show great potential for use in catalysis.Perovskite oxide catalysts with the composition LaMoxV1-xOn(z=0.1,0.3,0.5,0.7,and 0.9)have been synthe sized by the sol-gel method and then used in the ethane dry reforming reaction for the direct synthesis of acetic acid.The influence of the nature of the metallic source(metal,nitrate,acetylacetonate,and ammonium)on gel formation has been stud ied by Fourier-transfornl infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA-DTA).After calcination,the obtained perovskites were characterized bv X-ray diffraction(XRD)and energy-dispersive X-ray spectrometry(EDS)coupled with scanning electron microscopy(SEM).The catalysts were then subjected tO thermo-programmed reduction(TPR).The surface area(BET)was found to increase from 2.6 m2/g(x=0.1)to 5.1 m1/g(x=1.0)with increasing molybdenum content following calcinations at 750℃,and pure LaMoxV1-xOn perovskite was obtained with good homogeneity.The catalysts have been characterized by XRD,SEM,EDS,and carbon analysis(CA).The results indicate that through this synthesis it iS possible to obtain highly crystalline.homogeneous and pure solids,with well-defined structures.The direct synthesis of acetic acid from ethane over the perovskite catalysts was studied at temperatures between 450 and 850℃ and elevated pressures between 1 and 8 bar.It was foand that the yield of acetic acid and the selectivity of its formation could be increased by incorporating more molybdenum into the perovskite structure.The experimental studies have shown that the calcination temperature and the molybdenum content have a significant influence on the catalytic activity.Amongst the catalysts tested,LaMo0.7 V0.3O4.2exhibited the best activity and stability.

  15. Influence of anodization parameters on the volume expansion of anodic aluminum oxide formed in mixed solution of phosphoric and oxalic acids

    Science.gov (United States)

    Kao, Tzung-Ta; Chang, Yao-Chung

    2014-01-01

    The growth of anodic alumina oxide was conducted in the mixed solution of phosphoric and oxalic acids. The influence of anodizing voltage, electrolyte temperature, and concentration of phosphoric and oxalic acids on the volume expansion of anodic aluminum oxide has been investigated. Either anodizing parameter is chosen to its full extent of range that allows the anodization process to be conducted without electric breakdown and to explore the highest possible volume expansion factor. The volume expansion factors were found to vary between 1.25 and 1.9 depending on the anodizing parameters. The variation is explained in connection with electric field, ion transport number, temperature effect, concentration, and activity of acids. The formation of anodic porous alumina at anodizing voltage 160 V in 1.1 M phosphoric acid mixed with 0.14 M oxalic acid at 2 °C showed the peak volume expansion factor of 1.9 and the corresponding moderate growth rate of 168 nm/min.

  16. Chemical composition and oxidative status of tissues from Iberian pigs as affected by diets: extensive feeding v. oleic acid- and tocopherol-enriched mixed diets.

    Science.gov (United States)

    Ventanas, S; Tejeda, J F; Estévez, M

    2008-04-01

    The present work was intended to analyse the chemical composition and oxidative stability of the muscle biceps femoris and adipose tissues from Iberian pigs fed different finishing diets: free-range feeding on grass and acorns in a 'Montanera' traditional system (MON), fed in confinement with a mixed diet containing high-oleic sunflower oil (115 g/kg of diet) and supplemented with 250 mg/kg α-tocopherol (HOVE), and fed in confinement with a tocopherol-non-supplemented control mixed diet (CON). Muscles from MON pigs contained significantly (P < 0.05) higher amounts of intramuscular fat than those from HOVE and CON pigs. Muscles from MON and HOVE pigs had significantly higher levels of α-tocopherol than muscles from CON pigs whereas free-range feeding provided significantly higher levels of γ-tocopherol to muscles from MON pigs than the experimental diets did to CON and HOVE pigs. Adipose tissues from MON and HOVE pigs contained significantly lower proportions of saturated fatty acids and significantly higher levels of oleic acid and monounsaturated fatty acids than those from CON pigs. Tissues from MON pigs contained significantly smaller levels of polyunsaturated fatty acids than those from CON and HOVE pigs. To a higher extent, feeding background affected the fatty acid composition of polar lipids from the muscle biceps femoris than that of neutral lipids. Tissues from MON pigs contained significantly smaller ω-6/ω-3 values than those from pigs fed mixed diets. Compared to tissues from CON pigs, those from MON and HOVE pigs exhibited a higher oxidative stability as a likely result of a most favourable fatty acid composition and the presence of higher tocopherol levels.

  17. Chaotic, mixed-mode and periodic oscillations during the electro-oxidation of copper in trichloroacetic acid

    Directory of Open Access Journals (Sweden)

    HAITAO CUIa

    2004-01-01

    Full Text Available The current oscillations of a copper electrode in trichloroacetic acid solutions were studied in this paper. The Cu/CCl3COOH system is a new electrochemical oscillator, showing rich dynamic behaviour on two controllable parameters: the trichloroacetic acid concentration (cCCl3COOH and the imposed potential (E. Phase trajectories were reconstructed from time series using time delay methods in order that the complex oscillations could be analyzed. Five kinds of oscillations, periodic and quasiperiodic, mixed-mode, aperiodic, small amplitude and chaotic current oscillations, were observed. The EDS (energy dispersive spectroscopy technique was used to analyze the elemental composition of the film formed on the surface of the copper electrode after the current oscillations.

  18. Self-assembly of mixed Pt and Au nanoparticles on PDDA-functionalized graphene as effective electrocatalysts for formic acid oxidation of fuel cells.

    Science.gov (United States)

    Wang, Shuangyin; Wang, Xin; Jiang, San Ping

    2011-04-21

    Pt and Au nanoparticles with controlled Pt : Au molar ratios and PtAu nanoparticle loadings were successfully self-assembled onto poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene (PDDA-G) as highly effective electrocatalysts for formic acid oxidation in direct formic acid fuel cells (DFAFCs). The simultaneously assembled Pt and Au nanoparticles on PDDA-G showed superb electrocatalytic activity for HCOOH oxidation, and the current density associated with the preferred dehydrogenation pathway for the direct formation of CO(2) through HCOOH oxidation on a Pt(1)Au(8)/PDDA-G (i.e., a Pt : Au ratio of 1 : 8) is 32 times higher than on monometallic Pt/PDDA-G. The main function of the Au in the mixed Pt and Au nanoparticles on PDDA-G is to facilitate the first electron transfer from HCOOH to HCOO(ads) and the effective spillover of HCOO(ads) from Au to Pt nanoparticles, where HCOO(ads) is further oxidized to CO(2). The Pt : Au molar ratio and PtAu nanoparticle loading on PDDA-G supports are the two critical factors to achieve excellent electrocatalytic activity of PtAu/PDDA-G catalysts for the HCOOH oxidation reactions.

  19. Extensive feeding versus oleic acid and tocopherol enriched mixed diets for the production of Iberian dry-cured hams: Effect on chemical composition, oxidative status and sensory traits.

    Science.gov (United States)

    Ventanas, S; Ventanas, J; Tovar, J; García, C; Estévez, M

    2007-10-01

    The present study aimed to analyse the chemical composition and oxidative status of Iberian dry-cured hams from pigs fed different finishing diets: extensive feeding on acorns and pasture in a "Montanera" traditional system (MON), fed in confinement with a mixed diet containing high-oleic sunflower oil (115g/kg of diet) and supplemented with 250mg/kg α-tocopherol (HOVE), and fed in confinement control mixed diet (CON) without added tocopherol and oleic acid fat. Muscles from MON dry-cured hams contained significantly (p<0.05) higher amounts of intramuscular fat (IMF) than those from HOVE and CON hams. The feeding background affected the tocopherol levels in dry-cured hams as those from MON and HOVE pigs had significantly higher levels of α-tocopherol than those from CON pigs whereas the extensive feeding provided muscles from MON pigs with significantly higher levels of γ-tocopherol than the experimental diets did to CON and HOVE pigs. The HOVE diet significantly increased the levels of oleic acid in Iberian dry-cured hams with these levels being similar to the oleic acid levels found in MON hams and significantly higher than those in CON hams. Compared to dry-cured hams from CON pigs, those from MON and HOVE pigs exhibited a higher oxidative stability as a likely result of a most favourable fatty acid composition and the presence of higher tocopherol levels. The principal component analysis (PCA) successfully discriminated between dry-cured hams from pigs fed different finishing diets.

  20. Anodic aluminum oxide films formed in mixed electrolytes of oxalic and sulfuric acid and their optical constants

    Science.gov (United States)

    Zhao, Li-Rong; Wang, Jian; Li, Yan; Wang, Cheng-Wei; Zhou, Feng; Liu, Wei-Min

    2010-01-01

    Porous anodic aluminum oxide (AAO) films were fabricated electrochemically in the mixed electrolytes with various volume ratios of 0.3 M C 2H 2O 4 and 0.3 M H 2SO 4. The transmission spectra with the interference fringes were measured and the modified Swanepoel method was used to determine the optical constants of the free standing AAO films. The calculated thickness agrees well with the measured thickness from the FE-SEM images of the cross section, which indicates that the modified Swanepoel method is very fit for the determination of the optical constants of the free standing AAO films. Meantime, with the decrease of the volume ratio of C 2H 2O 4 and H 2SO 4, the refractive index and thickness of AAO films increase, but the extinction coefficient decreases. The optical band gap is appropriately fitted to the direct transition model proposed by Tauc in the strong-absorption region of investigated films, and is derived from Tauc's extrapolation. The reasons were investigated.

  1. Fatty Acid Oxidation Disorders

    Science.gov (United States)

    ... acid oxidation disorders are tested for in newborn screening? The March of Dimes recommends that all babies ... in behavior Diarrhea, nausea (feeling sick to your stomach) and throwing up Drowsiness Fever Fussiness Little appetite ...

  2. Thermal and sonochemical synthesis of porous (Ce,Zr)O2 mixed oxides from metal β-diketonate precursors and their catalytic activity in wet air oxidation process of formic acid.

    Science.gov (United States)

    Cau, Camille; Guari, Yannick; Chave, Tony; Larionova, Joulia; Nikitenko, Sergey I

    2014-07-01

    Porous (Ce0.5Zr0.5)O2 solid solutions were prepared by thermolysis (T=285 °C) or sonolysis (20 kHz, I=32 W cm(-2), Pac=0.46 W mL(-1), T=200 °C) of Ce(III) and Zr(IV) acetylacetonates in oleylamine or hexadecylamine under argon followed by heat treatment of the precipitates obtained in air at 450 °C. Transmission Electron Microscopy images of the samples show nanoparticles of ca. 4-6 nm for the two synthetic approaches. The powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and μ-Raman spectroscopy of solids obtained after heat treatment indicate the formation of (Ce0.5Zr0.5)O2 solid solutions with a metastable tetragonal crystal structure for the two synthetic routes. The specific surface area of the samples varies between 78 and 149 m(2) g(-1) depending on synthesis conditions. The use of Barrett-Joyner-Halenda and t-plot methods reveal the formation of mixed oxides with a hybrid morphology that combines mesoporosity and microporosity regardless of the method of preparation. Platinum nanoparticles were deposited on the surface of the mixed oxides by sonochemical reduction of Pt(IV). It was found that the materials prepared by sonochemistry exhibit better resistance to dissolution during the deposition process of platinum. X-ray photoelectron spectroscopy analysis shows the presence of Pt(0) and Pt(II) on the surface of mixed oxides. Porous (Ce0.5Zr0.5)O2 mixed oxides loaded with 1.5%wt. platinum exhibit high activity in catalytic wet air oxidation of formic acid at 40 °C. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Synthesis of fatty acid methyl ester from the transesterification of high- and low-acid-content crude palm oil (Elaeis guineensis) and karanj oil (Pongamia pinnata) over a calcium-lanthanum-aluminum mixed-oxides catalyst.

    Science.gov (United States)

    Syamsuddin, Y; Murat, M N; Hameed, B H

    2016-08-01

    The synthesis of fatty acid methyl ester (FAME) from the high- and low-acid-content feedstock of crude palm oil (CPO) and karanj oil (KO) was conducted over CaO-La2O3-Al2O3 mixed-oxide catalyst. Various reaction parameters were investigated using a batch reactor to identify the best reaction condition that results in the highest FAME yield for each type of oil. The transesterification of CPO resulted in a 97.81% FAME yield with the process conditions of 170°C reaction temperature, 15:1 DMC-to-CPO molar ratio, 180min reaction time, and 10wt.% catalyst loading. The transesterification of KO resulted in a 96.77% FAME yield with the conditions of 150°C reaction temperature, 9:1 DMC-to-KO molar ratio, 180min reaction time, and 5wt.% catalyst loading. The properties of both products met the ASTM D6751 and EN 14214 standard requirements. The above results showed that the CaO-La2O3-Al2O3 mixed-oxide catalyst was suitable for high- and low-acid-content vegetable oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Heterogeneous OH oxidation of palmitic acid in single component and internally mixed aerosol particles: vaporization and the role of particle phase

    Directory of Open Access Journals (Sweden)

    C. B. Stipe

    2008-09-01

    Full Text Available We studied the OH oxidation of submicron aerosol particles consisting of pure palmitic acid (PA or thin (near monolayer coatings of PA on aqueous and effloresced inorganic salt particles. Experiments were performed as a function of particle size and OH exposure using a continuous-flow photochemical reaction chamber coupled to a chemical ionization mass spectrometer (CIMS system, for detection of gas and particle-bound organics, and a DMA/CPC for monitoring particle size distributions. The loss rate of PA observed for pure PA aerosols and PA on crystalline NaCl aerosols indicates that the OH oxidation of PA at the gas-aerosol interface is efficient. The pure PA oxidation data are well represented by a model consisting of four main processes: 1 surface-only reactions between OH and palmitic acid, 2 secondary reactions between palmitic acid and OH oxidation products, 3 volatilization of condensed-phase mass, and 4 a surface renewal process. Using this model we infer a value of γOH between 0.8 and 1. The oxidation of palmitic acid in thin film coatings of salt particles is also efficient, though the inferred γOH is lower, ranging from ~0.3+0.1/−0.05 for coatings on solid NaCl and ~0.05 (±0.01 on aqueous NaCl particles. These results, together with simultaneous data on particle size change and volatilized oxidation products, provide support for the ideas that oxidative aging of aliphatic organic aerosol is a source of small oxidized volatile organic compounds (OVOCs, and that OH oxidation may initiate secondary condensed-phase reactions.

  5. The heterogeneous OH oxidation of palmitic acid in single component and internally mixed aerosol particles: vaporization, secondary chemistry, and the role of particle phase

    Directory of Open Access Journals (Sweden)

    V. F. McNeill

    2008-03-01

    Full Text Available We studied the OH oxidation of submicron aerosol particles consisting of pure palmitic acid (PA or thin (near monolayer coatings of PA on aqueous and effloresced inorganic salt particles. Experiments were performed as a function of particle size and OH exposure using a continuous-flow photochemical reaction chamber coupled to a chemical ionization mass spectrometer (CIMS system, for detection of gas and particle-bound organics, and a DMA/CPC for monitoring particle size distributions. The loss rate of PA observed for pure PA aerosols and PA on crystalline NaCl aerosols indicates that the OH oxidation of PA at the gas-aerosol interface is efficient. The pure PA oxidation data are well represented by a model consisting of four main processes: 1 surface-only reactions between OH and palmitic acid, 2 secondary reactions between palmitic acid and OH oxidation products, 3 volatilization of condensed-phase mass, and 4 a surface renewal process. Using this model we infer a value of γOH between 0.8 and 1. The oxidation of palmitic acid in thin film coatings of salt particles is also efficient, though the inferred γOH is lower, ranging from ~0.3 (+0.1/−0.05 for coatings on solid NaCl and ~0.05 (±0.01 on aqueous NaCl particles. These results, together with simultaneous data on particle size change and volatilized oxidation products, provide support for the ideas that oxidative aging of aliphatic organic aerosol is a source of small oxidized volatile organic compounds (OVOCs, and that OH oxidation may initiate secondary condensed-phase reactions.

  6. Tuning the acidity of niobia: Characterization and catalytic activity of Nb{sub 2}O{sub 5}–MeO{sub 2} (Me = Ti, Zr, Ce) mesoporous mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Stošić, Dušan; Bennici, Simona [Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne (France); Pavlović, Vladimir; Rakić, Vesna [Faculty of Agriculture, Department of Chemistry, University of Belgrade, Nemanjina 6, 11080 Zemun (Serbia); Auroux, Aline, E-mail: aline.auroux@ircelyon.univ-lyon1.fr [Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne (France)

    2014-08-01

    Mesoporous Nb{sub 2}O{sub 5}–MeO{sub 2} (Me = Ti, Zr, Ce) mixed oxides were successfully prepared using evaporation-induced self-assembly (EISA) method. The structural and textural properties of these materials have been fully characterized using appropriate techniques (low-temperature adsorption–desorption of nitrogen, thermogravimetric analysis, X-ray diffraction analysis (XRD) transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy). Acid–base properties were estimated by adsorption microcalorimetry of NH{sub 3} and SO{sub 2} molecules in order to determine the population, strength and strength distribution of acidic or basic sites. Formation of mesoporous structure was confirmed by the results of XRD, TEM and BET techniques. Results of adsorption microcalorimetry technique showed that the type of transition metal oxide added to niobia has a decisive role for acidic-basic character of investigated mixed oxides. Among the investigated mixed oxide formulations only Nb{sub 2}O{sub 5}–CeO{sub 2} was amphoteric, while the other samples showed prominent acidic character. All the investigated materials are catalytically active in fructose dehydration; conversion of fructose and selectivity to 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) are proved to be dependant on the number of acidic sites on the surface of catalysts. Furthermore, presence of the basic sites on the surface of the catalyst decreases the activity in the fructose dehydration reaction, as in the case of Nb{sub 2}O{sub 5}–CeO{sub 2} sample. - Highlights: • Mesoporous Nb{sub 2}O{sub 5}–MeO{sub 2} mixed oxides were successfully prepared by EISA method. • Acidic–basic properties depend on the nature of the oxide that was mixed with niobia. • Catalytic activity was tested in fructose dehydration in aqueous phase. • Selectivity and conversion in reaction are correlated to the number of acid sites.

  7. Mixed iron-manganese oxide nanoparticles

    NARCIS (Netherlands)

    Lai, Jriuan; Shafi, Kurikka V.P.M.; Ulman, Abraham; Loos, Katja; Yang, Nan-Loh; Cui, Min-Hui; Vogt, Thomas; Estournès, Claude; Locke, Dave C.

    2004-01-01

    Designing nanoparticles for practical applications requires knowledge and control of how their desired properties relate to their composition and structure. Here, we present a detailed systematic study of mixed iron-manganese oxide nanoparticles, showing that ultrasonication provides the high-energy

  8. Heterogeneous Partial (ammOxidation and Oxidative Dehydrogenation Catalysis on Mixed Metal Oxides

    Directory of Open Access Journals (Sweden)

    Jacques C. Védrine

    2016-01-01

    Full Text Available This paper presents an overview of heterogeneous partial (ammoxidation and oxidative dehydrogenation (ODH of hydrocarbons. The review has been voluntarily restricted to metal oxide-type catalysts, as the partial oxidation field is very broad and the number of catalysts is quite high. The main factors of solid catalysts for such reactions, designated by Grasselli as the “seven pillars”, and playing a determining role in catalytic properties, are considered to be, namely: isolation of active sites (known to be composed of ensembles of atoms, Me–O bond strength, crystalline structure, redox features, phase cooperation, multi-functionality and the nature of the surface oxygen species. Other important features and physical and chemical properties of solid catalysts, more or less related to the seven pillars, are also emphasized, including reaction sensitivity to metal oxide structure, epitaxial contact between an active phase and a second phase or its support, synergy effect between several phases, acid-base aspects, electron transfer ability, catalyst preparation and activation and reaction atmospheres, etc. Some examples are presented to illustrate the importance of these key factors. They include light alkanes (C1–C4 oxidation, ethane oxidation to ethylene and acetic acid on MoVTe(SbNb-O and Nb doped NiO, propene oxidation to acrolein on BiMoCoFe-O systems, propane (ammoxidation to (acrylonitrile acrylic acid on MoVTe(SbNb-O mixed oxides, butane oxidation to maleic anhydride on VPO: (VO2P2O7-based catalyst, and isobutyric acid ODH to methacrylic acid on Fe hydroxyl phosphates. It is shown that active sites are composed of ensembles of atoms whose size and chemical composition depend on the reactants to be transformed (their chemical and size features and the reaction mechanism, often of Mars and van Krevelen type. An important aspect is the fact that surface composition and surface crystalline structure vary with reaction on stream until

  9. Oxidation of phenolic acids by soil iron and manganese oxides

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, R.G.; Cheng, H.H.; Harsh, J.B.

    Phenolic acids are intermediary metabolites of many aromatic chemicals and may be involved in humus formation, allelopathy, and nutrient availability. Depending on their structures, six phenolic acids were shown to react at different rates with oxidized forms of Fe and Mn in a Palouse soil (fine-silty, mixed, mesic Pachic Ultic Haploxeroll). Increasing methoxy substitution on the aromatic ring of phenolic acids increased the reaction rate. Reaction rate was also increased for longer carboxyl-containing side chains. After 4 h reaction, little of the applied (10 mg kg/sup -1/ soil) p-hydroxybenzoic or p-coumaric acids had reacted, while 0 to 5, 70, 90, and 100% of the vanillic, ferulic, syringic, and sinapic acids, respectively, had reacted. After 72 h under conditions limiting microbial growth, none of the p-hydroxybenzoic, 30% of the p-coumaric, and 50% of the vanillic acids had reacted. The reaction was shown to be predominantly chemical, and not biological, since phenolic acid extractabilities were similar for Palouse soil and for Palouse soil pretreated with LiOBr to remove organic matter. When the Palouse soil was pretreated with a sodium dithionite-citrate solution to remove Fe and Mn oxides, none of the phenolic acids reacted after 1 h. The reaction of sinapic acid with Palouse soil was shown to produce Fe(II) and soluble Mn as reaction products. The reaction of phenolic acids with soil was thus shown to be an oxidation of the phenolic acids, coupled with a reduction of soil Fe and Mn oxides.

  10. Selective propene oxidation on mixed metal oxide catalysts

    CERN Document Server

    James, D W

    2002-01-01

    Selective catalytic oxidation processes represent a large segment of the modern chemical industry and a major application of these is the selective partial oxidation of propene to produce acrolein. Mixed metal oxide catalysts are particularly effective in promoting this reaction, and the two primary candidates for the industrial process are based on iron antimonate and bismuth molybdate. Some debate exists in the literature regarding the operation of these materials and the roles of their catalytic components. In particular, iron antimonate catalysts containing excess antimony are known to be highly selective towards acrolein, and a variety of proposals for the enhanced selectivity of such materials have been given. The aim of this work was to provide a direct comparison between the behaviour of bismuth molybdate and iron antimonate catalysts, with additional emphasis being placed on the component single oxide phases of the latter. Studies were also extended to other antimonate-based catalysts, including coba...

  11. Heterogeneous catalysis of mixed oxides perovskite and heteropoly catalysts

    CERN Document Server

    Misono, M

    2014-01-01

    Mixed oxides are the most widely used catalyst materials for industrial catalytic processes. The principal objective of this book is to describe systematically the mixed oxide catalysts, from their fundamentals through their practical applications.  After describing concisely general items concerning mixed oxide and mixed oxide catalysts, two important mixed oxide catalyst materials, namely, heteropolyacids and perovskites, are taken as typical examples and discussed in detail. These two materials have several advantages: 1. They are, respectively, typical examples of salts of oxoacids an

  12. Critical experiments with mixed oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Harris, D.R. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-06-01

    This paper very briefly outlines technical considerations in performing critical experiments on weapons-grade plutonium mixed oxide fuel assemblies. The experiments proposed would use weapons-grade plutonium and Er{sub 2}O{sub 3} at various dissolved boron levels, and for specific fuel assemblies such as the ABBCE fuel assembly with five large water holes. Technical considerations described include the core, the measurements, safety, security, radiological matters, and licensing. It is concluded that the experiments are feasible at the Rensselaer Polytechnic Institute Reactor Critical Facility. 9 refs.

  13. effects of mixed of mixed of mixed alkaline earth oxides in potash ...

    African Journals Online (AJOL)

    eobe

    The aim of this work is to investigate the effects of mixed alkaline earth oxide. The aim of this ... been studied. As for the method used, raw materials were collected, batch calculations were made, and the batches ... This research work therefore ...

  14. Analytical chemistry methods for mixed oxide fuel, March 1985

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-01

    This standard provides analytical chemistry methods for the analysis of materials used to produce mixed oxide fuel. These materials are ceramic fuel and insulator pellets and the plutonium and uranium oxides and nitrates used to fabricate these pellets.

  15. Direct chemical oxidation of mixed or toxic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, G B; Cooper, J F; Farmer, J C; Lewis, P

    1999-05-01

    Direct Chemical Oxidation (DCO) is an ambient-pressure, low-temperature (<100 C), and aqueous-based process for general-purpose destruction of the organic fraction of hazardous or mixed waste. It uses the peroxydisulfate anion (S{sub 2}O{sub 8}{sup 2{minus}}) in acid or base solutions. The byproduct of the oxidation reaction, typically sodium or ammonium hydrogen sulfate, may be recycled electrolytically to produce the oxidant. The oxidation kinetic reaction is first order with respect to the peroxydisulfate concentration, expressed in equivalents. The rate constant is constant for nearly all dissolved organic compounds: k{sub a} = 0.01 {+-} 0.005 min{sup {minus}1}. This reflects a common rate-determining step, which is the decomposition of the peroxydisulfate anion into the chemically active derivative, the sulfate radical anion, SO{sub 4}{sup {minus}}. This decomposition is promoted in DCO by raising the operating temperature into the range of 80-100 C. Rates are given for approximately 30 substances with diverse functional groups at low concentrations, and for a number of solid and liquid wastes typical of nuclear and chemical industries. The process has been scale up for treatment studies on chlorinated hydrocarbons, in which the hydrolysis of solvent mixtures was followed by oxidation of products in a series of stirred tank reactors. Cost estimates, safety considerations, and a comprehensive bibliography are given.

  16. Enhanced disinfection efficiency of mechanically mixed oxidants with free chlorine.

    Science.gov (United States)

    Son, Hyunju; Cho, Min; Kim, Jaeeun; Oh, Byungtaek; Chung, Hyenmi; Yoon, Jeyong

    2005-02-01

    To the best of our knowledge, this study is the first investigation to be performed into the potential benefits of mechanically mixed disinfectants in controlling bacterial inactivation. The purpose of this study was to evaluate the disinfection efficiency of mechanically mixed oxidants with identical oxidant concentrations, which were made by adding small amounts of subsidiary oxidants, namely ozone (O3), chlorine dioxide (ClO2), hydrogen peroxide (H2O2) and chlorite (ClO2(-)), to free available chlorine (Cl2), using Bacillus subtilis spores as the indicator microorganisms. The mechanically mixed oxidants containing Cl2/O3, Cl2/ClO2 and Cl2/ClO2(-) showed enhanced efficiencies (of up to 52%) in comparison with Cl2 alone, whereas no significant difference was observed between the mixed oxidant, Cl2/H2O2, and Cl2 alone. This enhanced disinfection efficiency can be explained by the synergistic effect of the mixed oxidant itself and the effect of intermediates such as ClO2(-)/ClO2, which are generated from the reaction between an excess of Cl2 and a small amount of O3/ClO2(-). Overall, this study suggests that mechanically mixed oxidants incorporating excess chlorine can constitute a new and moderately efficient method of disinfection.

  17. Aspirin increases mitochondrial fatty acid oxidation.

    Science.gov (United States)

    Uppala, Radha; Dudiak, Brianne; Beck, Megan E; Bharathi, Sivakama S; Zhang, Yuxun; Stolz, Donna B; Goetzman, Eric S

    2017-01-08

    The metabolic effects of salicylates are poorly understood. This study investigated the effects of aspirin on fatty acid oxidation. Aspirin increased mitochondrial long-chain fatty acid oxidation, but inhibited peroxisomal fatty acid oxidation, in two different cell lines. Aspirin increased mitochondrial protein acetylation and was found to be a stronger acetylating agent in vitro than acetyl-CoA. However, aspirin-induced acetylation did not alter the activity of fatty acid oxidation proteins, and knocking out the mitochondrial deacetylase SIRT3 did not affect the induction of long-chain fatty acid oxidation by aspirin. Aspirin did not change oxidation of medium-chain fatty acids, which can freely traverse the mitochondrial membrane. Together, these data indicate that aspirin does not directly alter mitochondrial matrix fatty acid oxidation enzymes, but most likely exerts its effects at the level of long-chain fatty acid transport into mitochondria. The drive on mitochondrial fatty acid oxidation may be a compensatory response to altered mitochondrial morphology and inhibited electron transport chain function, both of which were observed after 24 h incubation of cells with aspirin. These studies provide insight into the pathophysiology of Reye Syndrome, which is known to be triggered by aspirin ingestion in patients with fatty acid oxidation disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Sol-Gel/Hydrothermal Synthesis of Mixed Metal Oxide

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal ... the production of TiO -ZnO nanoparticles use. 2 either titanium ... involved using titanium sulphate and thioacetamide for ...

  19. Modulating fatty acid oxidation in heart failure.

    Science.gov (United States)

    Lionetti, Vincenzo; Stanley, William C; Recchia, Fabio A

    2011-05-01

    In the advanced stages of heart failure, many key enzymes involved in myocardial energy substrate metabolism display various degrees of down-regulation. The net effect of the altered metabolic phenotype consists of reduced cardiac fatty oxidation, increased glycolysis and glucose oxidation, and rigidity of the metabolic response to changes in workload. Is this metabolic shift an adaptive mechanism that protects the heart or a maladaptive process that accelerates structural and functional derangement? The question remains open; however, the metabolic remodelling of the failing heart has induced a number of investigators to test the hypothesis that pharmacological modulation of myocardial substrate utilization might prove therapeutically advantageous. The present review addresses the effects of indirect and direct modulators of fatty acid (FA) oxidation, which are the best pharmacological agents available to date for 'metabolic therapy' of failing hearts. Evidence for the efficacy of therapeutic strategies based on modulators of FA metabolism is mixed, pointing to the possibility that the molecular/biochemical alterations induced by these pharmacological agents are more complex than originally thought. Much remains to be understood; however, the beneficial effects of molecules such as perhexiline and trimetazidine in small clinical trials indicate that this promising therapeutic strategy is worthy of further pursuit.

  20. Sol-gel derived oxides and mixed oxides catalysts with narrow mesoporous distribution

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel sol-gel process for preparing oxides and mixed oxides sols from precipitation and peptization process is reported in this article. Inorganic salts are used as raw materials in this study. It is found that the amount of acid has great influence on the stability and particle diameter distribution of the precursor sols. Ultrasonic treatment is used to prepare alumina sol at room temperature. The result of 27Al NMR shows that there exist Al137+ species in the sol. By controlling the sol particles with narrow particle diameter distribution, alumina, titania and silica-alumina (SA) materials with narrow mesoporous distribution are formed by regular packing of sol particles during gelation without using any templates. The results also show that the structure and particle diameter distribution of precursor sol determine the final materials' texture.

  1. Optical and electrical studies of cerium mixed oxides

    Science.gov (United States)

    Sherly, T. R.; Raveendran, R.

    2014-10-01

    The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

  2. Optical and electrical studies of cerium mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Sherly, T. R., E-mail: trsherly@gmail.com [Post Graduate Department of Physics, Sanathana Dharma College, Alappuzha, Kerala (India); Raveendran, R. [Nanoscience Research Laboratory, Sree Narayana College, Kollam, Kerala 691001 (India)

    2014-10-15

    The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

  3. Nickel inhibits mitochondrial fatty acid oxidation.

    Science.gov (United States)

    Uppala, Radha; McKinney, Richard W; Brant, Kelly A; Fabisiak, James P; Goetzman, Eric S

    2015-08-07

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation-the pathway by which fatty acids are catabolized for energy-in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with l-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 h), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis.

  4. Kinetics of wet oxidation of formic acid and acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Mahajani, V.V. [Univ. of Mumbai (India). Dept. of Chemical Technology

    1997-11-01

    Oxidation of lower molecular weight carboxylic acids such as formic, acetic, glyoxalic, and oxalic acids is often the rate-controlling step during wet oxidation (WO) of an aqueous waste stream exhibiting very high chemical oxygen demand (COD). The kinetics of WO of formic acid was studied in the absence and presence of a cupric sulfate as catalyst in the temperature range 150--240 C and oxygen partial pressure range 0.345--1.380 MPa. Wet oxidation of acetic acid was carried out in the presence of cupric sulfate in the temperature range 215--235 C. Homogeneous copper sulfate was found to be a very good catalyst for oxidation of formic acid and acetic acid.

  5. A hybrid water-splitting cycle using copper sulfate and mixed copper oxides

    Science.gov (United States)

    Schreiber, J. D.; Remick, R. J.; Foh, S. E.; Mazumder, M. M.

    1980-01-01

    The Institute of Gas Technology has derived and developed a hybrid thermochemical water-splitting cycle based on mixed copper oxides and copper sulfate. Similar to other metal oxide-metal sulfate cycles that use a metal oxide to 'concentrate' electrolytically produced sulfuric acid, this cycle offers the advantage of producing oxygen (to be vented) and sulfur dioxide (to be recycled) in separate steps, thereby eliminating the need of another step to separate these gases. The conceptual process flow-sheet efficiency of the cycle promises to exceed 50%. It has been completely demonstrated in the laboratory with recycled materials. Research in the electrochemical oxidation of sulfur dioxide to produce sulfuric acid and hydrogen performed at IGT indicates that the cell performance goals of 200 mA/sq cm at 0.5 V will be attainable using relatively inexpensive electrode materials.

  6. Selective oxidation of isobutane on V–Mo–O mixed oxide catalysts

    Directory of Open Access Journals (Sweden)

    GHEORGHITA MITRAN

    2008-01-01

    Full Text Available Four V–Mo–O mixed metal oxides were prepared, characterized and tested for the selective oxidation of isobutane in the temperature range 350–550 °C, at atmospheric pressure. Isobutane was mainly oxidized to iso-butene and carbon oxides. The systems with low vanadium contents showed low activities but high isobutene selectivities, while the systems with high vanadium contents showed high activities with high carbon oxides selectivities. The effects of temperature, contact time and the molar ratio iso-butane to oxygen on the conversion of isobutane and the selectivity of the oxidation were studied.

  7. Wet oxidation of salicylic acid solutions.

    Science.gov (United States)

    Collado, Sergio; Garrido, Laura; Laca, Adriana; Diaz, Mario

    2010-11-15

    Salicylic acid is a frequent pollutant in several industrial wastewaters. Uncatalyzed wet air oxidation, which is a promising technique for the treatment of phenolic effluents, has not been analyzed yet for the removal of salicylic acid. The effect of different conditions of pH (1.3-12.3), pressure (1.0-4.1 MPa), temperature (413-443 K), and initial concentrations (1.45-14.50 mM) on the wet oxidation of salicylate/salicylic acid solutions have here been investigated. The pH value of the reaction media was found to be a key parameter for the rate of the oxidation process with an optimum at pH 3.1, when the concentrations of salicylic acid and salicylate were similar. The oxidation reaction followed pseudofirst-order kinetics with respect to salicylic acid and 0.82 order with respect to dissolved oxygen. Additionally, the evolution of the color during the wet oxidation was analyzed and discussed in relation with the formation of intermediate compounds. Then, a reaction pathway for the noncatalytic wet oxidation of the salicylic acid was proposed.

  8. Photochemical oxidation: A solution for the mixed waste dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Prellberg, J.W.; Thornton, L.M.; Cheuvront, D.A. [Vulcan Peroxidation Systems, Inc., Tucson, AZ (United States)] [and others

    1995-12-31

    Numerous technologies are available to remove organic contamination from water or wastewater. A variety of techniques also exist that are used to neutralize radioactive waste. However, few technologies can satisfactorily address the treatment of mixed organic/radioactive waste without creating unacceptable secondary waste products or resulting in extremely high treatment costs. An innovative solution to the mixed waste problem is on-site photochemical oxidation. Liquid-phase photochemical oxidation has a long- standing history of successful application to the destruction of organic compounds. By using photochemical oxidation, the organic contaminants are destroyed on-site leaving the water, with radionuclides, that can be reused or disposed of as appropriate. This technology offers advantages that include zero air emissions, no solid or liquid waste formation, and relatively low treatment cost. Discussion of the photochemical process will be described, and several case histories from recent design testing, including cost analyses for the resulting full-scale installations, will be presented as examples.

  9. Production of Caproic Acid from Mixed Organic Waste

    NARCIS (Netherlands)

    Chen, Wei Shan; Strik, David P.B.T.B.; Buisman, Cees J.N.; Kroeze, Carolien

    2017-01-01

    Caproic acid is an emerging platform chemical with diverse applications. Recently, a novel biorefinery process, that is, chain elongation, was developed to convert mixed organic waste and ethanol into renewable caproic acids. In the coming years, this process may become commercialized, and

  10. Acid monolayer functionalized iron oxide nanoparticle catalysts

    Science.gov (United States)

    Ikenberry, Myles

    Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80° and starch at 130°, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide

  11. Direct Oxidation of Ethene to Acetic Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Direct oxidation of ethene to acetic acid over Pd-SiW12/SiO2 catalysts prepared by several methods was studied. A better method for reducing palladium composition of the catalysts was found. Acetic acid was obtained with selectivity of 82.7% and once-through space time yield (STY) of 257.4 g/h×L.

  12. Photo-oxidation of organic compounds in liquid low-level mixed wastes at the INEL

    Energy Technology Data Exchange (ETDEWEB)

    Gering, K.L.; Schwendiman, G.L.

    1996-08-01

    A bench-scale oxidation apparatus is implemented to study the effectiveness of using an artificial ultraviolet source, a 175-watt medium pressure mercury vapor lamp, to enhance the destruction of organic contaminants in water with chemical oxidants. The waste streams used in this study are samples or surrogates of mixed wastes at the Idaho National Engineering Laboratory. The contaminants that are investigated include methylene chloride, 1,1,1-trichlorethane, 1, 1-dichlororethane, acetone, 2-propanol, and ethylenediamine tetraacetic acid. We focus on H{sub 2}O{sub 2}-based oxidizers for our treatment scheme, which include the UV/H{sub 2}O{sub 2} system, the dark Fenton system (H{sub 2}O{sub 2}/Fe{sup 2+}), and the photo- assisted Fenton system (UV/H{sub 2}O{sub 2}/Fe{sup 3+}) is used in particular. Variables include concentration of the chemical oxidizer, concentration of the organic contaminant, and the elapsed reaction time. Results indicate that the photo-assisted Fenton system provides the best overall performance of the oxidizing systems listed above, where decreases in concentrations of methylene chloride, 1,1,1- trichloroethane, 1,1-dichlororethane, 2-propanol, and ethylenediamine tetraacetic acid were seen. However, UV-oxidation treatment provided no measurable benefit for a mixed waste containing acetone in the presence of 2-propanol.

  13. Fatty acid oxidation and ketogenesis in astrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Auestad, N.

    1988-01-01

    Astrocytes were derived from cortex of two-day-old rat brain and grown in primary culture to confluence. The metabolism of the fatty acids, octanoate and palmitate, to CO{sub 2} in oxidative respiration and to the formation of ketone bodies was examined by radiolabeled tracer methodology. The net production of acetoacetate was also determined by measurement of its mass. The enzymes in the ketogenic pathway were examined by measuring enzymic activity and/or by immunoblot analyses. Labeled CO{sub 2} and labeled ketone bodies were produced from the oxidation of fatty acids labeled at carboxy- and {omega}-terminal carbons, indicating that fatty acids were oxidized by {beta}-oxidation. The results from the radiolabeled tracer studies also indicated that a substantial proportion of the {omega}-terminal 4-carbon unit of the fatty acids bypassed the {beta}-ketothiolase step of the {beta}-oxidation pathway. The ({sup 14}C)acetoacetate formed from the (1-{sup 14}C)labeled fatty acids, obligated to pass through the acetyl-CoA pool, contained 50% of the label at carbon 3 and 50% at carbon 1. In contrast, the ({sup 14}C)acetoacetate formed from the ({omega}-1)labeled fatty acids contained 90% of the label at carbon 3 and 10% at carbon 1.

  14. Design and synthesis of mixed oxides nanoparticles for biofuel applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Senniang [Iowa State Univ., Ames, IA (United States)

    2010-05-15

    The work in this dissertation presents the synthesis of two mixed metal oxides for biofuel applications and NMR characterization of silica materials. In the chapter 2, high catalytic efficiency of calcium silicate is synthesized for transesterfication of soybean oil to biodisels. Chapter 3 describes the synthesis of a new Rh based catalyst on mesoporous manganese oxides. The new catalyst is found to have higher activity and selectivity towards ethanol. Chapter 4 demonstrates the applications of solid-state Si NMR in the silica materials.

  15. Mixed solvent system for treating acidic gas

    Energy Technology Data Exchange (ETDEWEB)

    Capobianco, P.J.; Butwell, K.F.; Kossakowski, E.J.

    1987-11-10

    This invention discloses mixtures of alkyl dialcohol amines and mono alkyl ethers of polyethylene glycols which are useful in removing acidic gases from gaseous mixtures. The solvent mixtures contain between 1.5 N and 5.0 N methyl diethanolamine (MDEA), 10 to 40 percent water and the balance is methoxytriglycol (MTG). The overall heat of reaction of the solution is typically less than 500 BTU/lb CO/sub 2/, and remains as a single liquid phase during normal gas scrubber operating conditions.

  16. XPS study of surface absorbed oxygen of ABO3 mixed oxides

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xin; YANG Qiuhua; CUI Jinjin

    2008-01-01

    Perovskite-type complex oxides ABO3 (A=Sr, La;B=Mn, Fe, Co) were prepared by citric acid method. The degradation of water-solubilized dyes was carried out using the mixed oxides as photocatalyst. The surface absorbed oxygen was analyzed using X-ray photoelectron spectroscopy (XPS). The results indicated that there was a relationship between the photocatalytic activity and the content of the surface absorbed oxygen. The higher the content of the surface absorbed oxygen was, the better the performance of the photocatalyst.

  17. Development of advanced mixed oxide fuels for plutonium management

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, S.; Beard, C.; Buksa, J.; Butt, D.; Chidester, K.; Havrilla, G.; Ramsey, K.

    1997-06-01

    A number of advanced Mixed Oxide (MOX) fuel forms are currently being investigated at Los Alamos National Laboratory that have the potential to be effective plutonium management tools. Evolutionary Mixed Oxide (EMOX) fuel is a slight perturbation on standard MOX fuel, but achieves greater plutonium destruction rates by employing a fractional nonfertile component. A pure nonfertile fuel is also being studied. Initial calculations show that the fuel can be utilized in existing light water reactors and tailored to address different plutonium management goals (i.e., stabilization or reduction of plutonium inventories residing in spent nuclear fuel). In parallel, experiments are being performed to determine the feasibility of fabrication of such fuels. Initial EMOX pellets have successfully been fabricated using weapons-grade plutonium.

  18. Structure Characterization of Semiconducting Tin and Tungsten Mixed Oxides

    Science.gov (United States)

    Solis, J. L.; Frantti, J.; Lantto, V.; Häggström, L.; Wikner, M.

    Mixed-oxide powders of tin and tungsten were made by heating various mixtures of SnO and WO3 powders, corresponding to the nominal formula SnxWO3+x with x between 0.5 and 2.0, in an argon atmosphere at 600°C for 15 hours. The α-SnWO4 phase was the result of heating of an equi-molar mixture of SnO and WO3 powders. In addition to 119Sn Mössbauer experiments, X-ray diffraction and Raman spectroscopy were used to study the phase structures of the mixed-oxide powders. Mössbauer spectra from all samples show a small peak at ∽0mm/s from phase(s) like rutile SnO2, and a larger peak doublet centred at ∽3.4mm/s from the α-SnWO4 phase, where tin is in the form Sn4+ and Sn2+, respectively. Another peak doublet centred at ∽3.0mm/s was needed to obtain reasonable fits for samples with x≥1.3. This doublet originates from an undocumented phase where tin is also in the divalent form Sn2+. 119Sn Mössbauer spectroscopy made it possible to reveal the relative amounts of the two valence states of tin in the mixed-oxide structures. Raman spectroscopy as the other probe for ``local'' structures was insensitive to reveal the changes in the phase structures between different mixed-oxide samples up to x=1.72, but an extra peak at ∽890cm-1 in the Raman spectrum from the sample with x=2.0 indicates also the presence of the undocumented phase.

  19. Microstructure and thermophysical characterization of mixed oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Freibert, Franz J [Los Alamos National Laboratory; Salich, Tarik A [Los Alamos National Laboratory; Schwartz, Daniel S [Los Alamos National Laboratory; Hampel, Fred G [Los Alamos National Laboratory; Mitchell, Jeremy N [Los Alamos National Laboratory; Davis, Charles C [Los Alamos National Laboratory; Neuman, Angelique D [Los Alamos National Laboratory; Willson, Steve P [Los Alamos National Laboratory; Dunwoody, John T [Los Alamos National Laboratory

    2009-01-01

    Pre-irradiated thermodynamic and microstructural properties of nuclear fuels form the necessary set of data against which to gauge fuel performance and irradiation damage evolution. This paper summarizes recent efforts in mixed-oxide and minor actinide-bearing mixed-oxide ceramic fuels fabrication and characterization at Los Alamos National Laboratory. Ceramic fuels (U{sub 1-x-y-z}u{sub x}Am{sub y}Np{sub z})O{sub 2} fabricated in the compositional ranges of 0.19 {le} x {le} 0.3 Pu, 0 {le} y {le} 0.05 Am, and O {le} z {le} O.03 Np exhibited a uniform crystalline face-centered cubic phase with an average grain size of 14{micro}m; however, electron microprobe analysis revealed segregation of NpO{sub 2} in minor actinide-bearing fuels. Immersion density and porosity analysis demonstrated an average density of 92.4% theoretical for mixed-oxide fuels and an average density of 89.5 % theoretical density for minor actinide-bearing mixed-oxide fuels. Examined fuels exhibited mean thermal expansion value of 12.56 x 10{sup -6} C{sup -1} for temperature range (100 C < T < 1500 C) and ambient temperature Young's modulus and Poisson's ratio of 169 GPa and of 0.327, respectively. Internal dissipation as determined from mechanical resonances of these ceramic fuels has shown promise as a tool to gauge microstructural integrity and to interrogate fundamental properties.

  20. Conversion of ethanol to 1,3-butadiene over Na doped ZnxZryOz mixed metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Baylon, Rebecca A.; Sun, Junming; Wang, Yong

    2016-01-01

    Despite numerous studies on different oxide catalysts for the ethanol to 1,3-butadiene reaction, few have identified active sites (i.e., type of acidity) correlated to the catalytic performances. In this work, the type of acidity needed for ethanol to 1,3-butadiene conversion has been studied over Zn/Zr mixed oxide catalysts. Specifically, synthesis method, Zn/Zr ratio, and Na doping have been used to control the surface acid-base properties, as confirmed by characterizations such as NH3-TPD and IR-Py techniques. The 2000 ppm Na doped Zn1Zr10Oz-H with balanced base and weak Bronsted acid sites was found to give not only high selectivity to 1,3-butadiene (47%) at near complete ethanol conversion (97%), but also exhibited a much higher 1,3-butadiene productivity than other mixed oxides studied.

  1. Mixed metal oxide crystalline powders and method for the synthesis thereof

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, I.H.; Blonski, R.P.; Maloney, J.J.; Welch, J.J.; Pipoly, R.A.; Byrne, C.J.

    1993-07-20

    A method is described for the solid state synthesis of mixed metal oxide crystalline powders comprising the steps of: preparing a raw material mixture containing at least two different metal cations; adding a template material to said mixture and blending it therewith; initiating formation of a mixed metal oxide by calcination of said mixture and said template material, whereby particles of the mixed metal oxides are formed in powder form; and thereafter recovering said mixed metal oxide particles.

  2. Selective oxidation of benzylic alcohols using copper-manganese mixed oxide nanoparticles as catalyst

    Directory of Open Access Journals (Sweden)

    Roushown Ali

    2015-07-01

    Full Text Available The catalytic activity of copper-manganese (CuMn2 mixed oxide nanoparticles (Cu/Mn = 1:2 has been studied for the selective oxidation of benzylic alcohols to the corresponding aldehydes using molecular oxygen as an oxidizing agent. The CuMn2 mixed oxide showed excellent catalytic activity for the oxidation of benzylic alcohols to the corresponding aldehydes with high selectivity (>99%. The complete conversion (100% of all the benzylic alcohols to the corresponding aldehydes is achieved within a short reaction period at 102 °C. The catalytic performance is obtained to be dependent on the electronic and steric effects of the substituents present on the phenyl ring. Electron withdrawing and bulky groups attached to the phenyl ring required longer reaction time for a complete conversion of the benzylic alcohols.

  3. Crystalline structure of mixed metal oxide catalysts for propane selective oxidation to acrylic acid%丙烷选择氧化制丙烯酸复合金属氧化物催化剂晶体结构的研究

    Institute of Scientific and Technical Information of China (English)

    于振兴; 郑伟; 徐文龙; 张平; 付红英; 张宇航

    2011-01-01

    The effects of the preparation procedure on the formation of crystal phases and catalytic performance of the MoVTeNbO mixed metal oxide catalysts in selective oxidation of propane to acrylic acid were investigated.The results show that the preferred drying method is the rotavapor method,which favors the formation of an effective crystal phase and suppresses the formation of impurity phases.The preferred calcination atmosphere is an Ar atmosphere.The MoVTeNb mixed metal oxide catalysts can be obtained by solution method after heat-treatment at 600 ℃ in an Ar atmosphere,via a rotavapor with a warm water bath at 60 ℃,and a pH value of 4.0.The catalyst with a MoVTeNb molar ratio of 1.0:0.3:0.23:0.12 is the most effective and extremely active.%研究制备过程对丙烷选择氧化制丙烯酸所用MoVTeNbO复合金属氧化物催化剂晶相的形成及其催化性能的影响.最优的干燥方法是用旋转蒸发仪进行干燥,该方法有利于有效晶相的形成和杂质相的抑制.最佳的催化剂焙烧气氛是氩气.X射线衍射分析结果表明,在采用溶液法制备、旋转蒸发干燥温度为60℃、pH值为4.0、氩气为保护气、煅烧温度为600℃等条件下,可获得MoVTeNb复合金属氧化物催化剂.当该催化剂的MoVTeNb摩尔比为1.0:0.3:0.23:0.12时具有最高的催化活性.

  4. Prevalent mutations in fatty acid oxidation disorders

    DEFF Research Database (Denmark)

    Gregersen, N; Andresen, B S; Bross, P

    2000-01-01

    UNLABELLED: The mutational spectrum in a given disease-associated gene is often comprised of a large number of different mutations, of which a single or a few are present in a large proportion of diseased individuals. Such prevalent mutations are known in four genes of the fatty acid oxidation: t...... of the disease in question and determination of the carrier frequency in the general population may help in elucidating the penetrance of the genotype. This is exemplified in disorders of mitochondrial fatty acid oxidation....

  5. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Science.gov (United States)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  6. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Science.gov (United States)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  7. 40 CFR 721.10147 - Acrylate derivative of alkoxysilylalkane ester and mixed metal oxides (generic).

    Science.gov (United States)

    2010-07-01

    ... alkoxysilylalkane ester and mixed metal oxides (generic). 721.10147 Section 721.10147 Protection of Environment... alkoxysilylalkane ester and mixed metal oxides (generic). (a) Chemical substance and significant new uses subject to... ester and mixed metal oxides (PMN P-07-198) is subject to reporting under this section for...

  8. 40 CFR 721.5315 - Nickel, cobalt mixed metal oxide (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nickel, cobalt mixed metal oxide... Specific Chemical Substances § 721.5315 Nickel, cobalt mixed metal oxide (generic). (a) Chemical substance... nickel, cobalt mixed metal oxide. (PMN P-02-90) is subject to reporting under this section for the...

  9. Flexible Electronics Powered by Mixed Metal Oxide Thin Film Transistors

    Science.gov (United States)

    Marrs, Michael

    A low temperature amorphous oxide thin film transistor (TFT) and amorphous silicon PIN diode backplane technology for large area flexible digital x-ray detectors has been developed to create 7.9-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide TFT and a-Si PIN photodiode process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication and assembly of the flexible detectors. Mixed oxide semiconductor TFTs on flexible plastic substrates suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer improves both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment to the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors. Low temperature (200°C) processed amorphous silicon photodiodes were developed successfully by balancing the tradeoffs

  10. Hydrothermal Synthesis, Characterization and Catalytic Properties of Nanoporous MoO3/ZrO2 Mixed Oxide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A nanoporous MoO3/ZrO2 mixed oxide was hydrothermally synthesized by hydrolyzing zirconium isopropoxide in the presence of a cationic surfactant, cetyltrimethylammonium bromide(CTAB). The crystal structure and the acidity of the obtained nanoporous MoO3/ZrO2 mixed oxide were determined by means of XRD, N2 adsorption-desorption and NH3-TPD, respectively. The isobutane/butene alkylation over the MoO3/ZrO2 catalyst was carried out in a fixed bed reactor. The results reveal that ZrO2 in MoO3/ZrO2 exists mainly in the tetragonal phase, and the catalyst samples possess large specific surface areas as well as moderate acidity for isobutane/butene alkylation. Compared with samples prepared by impregnation and sol-gel processes, MoO3/ZrO2 mixed oxide samples prepared in this work have a better catalytic activity.

  11. Aromatic nitrations by mixed acid. Fast liquid-liquid regime

    NARCIS (Netherlands)

    Zaldivar, J.M.; Zaldivar, J.M.; Molga, E.J.; Alos, M.A.; Hernandez, H.; Westerterp, K.R.

    1996-01-01

    Aromatic nitration by mixed acid was selected as a specific case of heterogeneous liquid-liquid reaction. An extensive experimental programme was followed using adiabatic and heat flow calorimetry and pilot reactor experiments, supported by chemical analysis. A series of nitration experiments was

  12. Mixed protonic and electronic conductors hybrid oxide synaptic transistors

    Science.gov (United States)

    Fu, Yang Ming; Zhu, Li Qiang; Wen, Juan; Xiao, Hui; Liu, Rui

    2017-05-01

    Mixed ionic and electronic conductor hybrid devices have attracted widespread attention in the field of brain-inspired neuromorphic systems. Here, mixed protonic and electronic conductor (MPEC) hybrid indium-tungsten-oxide (IWO) synaptic transistors gated by nanogranular phosphorosilicate glass (PSG) based electrolytes were obtained. Unique field-configurable proton self-modulation behaviors were observed on the MPEC hybrid transistor with extremely strong interfacial electric-double-layer effects. Temporally coupled synaptic plasticities were demonstrated on the MPEC hybrid IWO synaptic transistor, including depolarization/hyperpolarization, synaptic facilitation and depression, facilitation-stead/depression-stead behaviors, spiking rate dependent plasticity, and high-pass/low-pass synaptic filtering behaviors. MPEC hybrid synaptic transistors may find potential applications in neuron-inspired platforms.

  13. Structure and growth of polymeric niobia-silica mixed-oxide sols for microporous molecular sieving membranes: a SAXS study

    NARCIS (Netherlands)

    Boffa, V.; Castricum, H.L.; Garcia, R.; Schmuhl, R.; Petukhov, A.V.; Blank, D.H.A.; ten Elshof, J.E.

    2009-01-01

    Branched polymeric niobia-silica (NS) mixed-oxide sols with a Nb:Si molar ratio between 0.33 and 0.8 were made by acid-catalyzed sol-gel synthesis and characterized using small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS). The growth rate of NS sols after addition of a niobium al

  14. Synthesis and characterization of mixed melilite-type oxides

    Science.gov (United States)

    Granata, V.; Ubaldini, A.; Fittipaldi, R.; Rocco, L.; Pace, S.; Vecchione, A.

    2017-01-01

    The melilite-type oxides are potential targets for exploring interesting magnetic and electronic properties as well as multiferroicity and magnetoelectric effects. Polycrystalline samples of Ba2Cu1-xMnxGe2O7 have been synthesized by solid state reaction method. The morphology and chemical composition of the samples have been investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). By using powder X-ray diffraction, the phase composition of the synthesized compounds and the evolution of their crystallographic axes as a function of the doping have been systematically studied. The synthesis of the polycrystalline compounds reported in this work is a prerequisite for the growth of high quality single crystals of mixed melilite-type oxides essential for the investigations of the complex magnetic phase diagram of these non-centrosymmetric systems.

  15. Surface and bulk aspects of mixed oxide catalytic nanoparticles: oxidation and dehydration of CH(3)OH by polyoxometallates.

    Science.gov (United States)

    Nakka, Lingaiah; Molinari, Julie E; Wachs, Israel E

    2009-10-28

    The molecular structures and surface chemistry of mixed metal oxide heteropolyoxo vanadium tungstate (H(3+x)PW(12-x)V(x)O(40) with x = 0, 1, 2, and 3) Keggin nanoparticles (NPs), where vanadium is incorporated into the primary Keggin structure, and supported VO(x) on tungstophosphoric acid (TPA, H(3)PW(12)O(40)), where vanadium is present on the surface of the Keggin unit, were investigated with solid-state magic angle spinning (51)V NMR, FT-IR, in situ Raman, in situ UV-vis, CH(3)OH temperature-programmed surface reaction (TPSR), and steady-state methanol oxidation. The incorporated VO(x) unit possesses one terminal V horizontal lineO bond, four bridging V-O-W/V bonds, and one long V-O-P bond in the primary Keggin structure, and the supported VO(x) unit possesses a similar coordination in the secondary structure under ambient conditions. The specific redox reaction rate for VO(x) in the Keggin primary structure is comparable to that of bulk V(2)O(5) and the more active supported vanadium oxide catalysts. The specific acidic reaction rate for the WO(x) in the TPA Keggin, however, is orders of magnitude greater than found for bulk WO(3), supported tungsten oxide catalysts, and even the highly acidic WO(3)-ZrO(2) catalyst synthesized by coprecipitation of ammonium metatungstate and ZrO(OH)(2). From CH(3)OH-TPSR and in situ Raman spectroscopy it was found that incorporation of vanadium oxide into the primary Keggin structure is also accompanied by the formation of surface VO(x) species at secondary sites on the Keggin outer surface. Both CH(3)OH-TPSR and steady-state methanol oxidation studies demonstrated that the surface VO(x) species on the Keggin outer surface are significantly less active than the VO(x) species incorporated into the primary Keggin structure. The presence of the less active surface VO(x) sites in the Keggins, thus, decreases the specific reaction rates for both methanol oxidation and methanol dehydration. During methanol oxidation/dehydration (O(2

  16. Ceria doped mixed metal oxide nanoparticles as oxidation catalysts: Synthesis and their characterization

    Directory of Open Access Journals (Sweden)

    S.S.P. Sultana

    2015-11-01

    Full Text Available Mixed metal nanoparticles (NPs have attracted significant attention as catalysts for various organic transformations. In this study, we have demonstrated the preparation of nickel–manganese mixed metal oxide NPs doped with X% nano cerium oxide (X = 1, 3, 5 mol% by a facile co-precipitation technique using surfactant and surfactant free methodologies. The as-synthesized materials were calcined at different temperatures (300 °C, 400 °C, and 500 °C, and were characterized using various spectroscopic techniques, including, FTIR and XRD. SEM analysis, TEM analysis and TGA were employed to evaluate the structural properties of the as-prepared catalyst. These were evaluated for their catalytic behaviour towards the conversion of benzyl alcohol to benzaldehyde, which was used as a model reaction with molecular oxygen as oxidant. Furthermore, the effect of the variation of the percentage of nano ceria doping and the calcination temperature on the performance of as-prepared mixed metal catalysts was also evaluated. The kinetic studies of the reactions performed employing gas chromatographic technique have revealed that the mixed metal oxide catalyst doped with 5% nano ceria displayed excellent catalytc activity, among various catalysts synthesized.

  17. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    Science.gov (United States)

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  18. Uptake of ozone to mixed sodium bromide/ citric acid solutions

    Science.gov (United States)

    Lee, Ming-Tao; Steimle, Emilie; Bartels-Rausch, Thorsten; Kato, Shunsuke; Lampimäki, Markus; Brown, Matthew; van Bokhoven, Jeroen; Nolting, Frithjof; Kleibert, Armin; Türler, Andreas; Ammann, Markus

    2013-04-01

    Sea-salt solution - air interfaces play an important role in the chemistry of the marine boundary layer. The reaction of ozone (O3) with bromide is of interest in the context of formation of photolabile halogens (Br2, BrCl) in the marine boundary layer. Recent experiments have suggested that the bromide oxidation rate is related to the surface concentration of bromide [1] and inversely related to the gas phase concentration of O3, an indication for a precursor mediated reaction at the surface [2]. So far, the effect of organics (such as those occurring at the ocean surface or in marine aerosols) on the reaction of O3 with bromide aerosols has not been studied yet. In our study we investigate the uptake kinetics of O3 to a mixed solution of sodium bromide (NaBr) and citric acid (CA), which represents highly oxidized organic compounds present in the environment, with a well-established coated wall flow tube technique, which leads to exposure of the film to O3 allowing the heterogeneous reactions to take place and the loss of O3 being measured. The results indicate that the uptake of O3 to the films with the higher bromide concentrations (0.34M and 4M) is independent of the gas phase concentration and roughly consistent with uptake limited by reaction in the bulk. For the lower bromide concentration (84mM), however, we observe a trend of the uptake coefficient to decrease with increasing O3 concentration, indicating an increasing importance of a surface reaction. In an attempt to constrain the kinetic data, we employed X-ray photoelectron spectroscopy (XPS) to get insight into the surface composition of the aqueous solution - air interface. Previous XPS studies have shown that halide ion concentrations are enhanced at the aqueous solution air interface [3-4], which likely promotes the surface reactions of bromide or iodide with O3. A first XPS study of ternary solutions of KI with butanol indicated the importance of specific interactions of the cation with the alcohol

  19. Conversion of Syngas-Derived C2+ Mixed Oxygenates to C3-C5 Olefins over ZnxZryOz Mixed Oxides Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Colin D.; Lebarbier, Vanessa M.; Flake, Matthew D.; Ramasamy, Karthikeyan K.; Kovarik, Libor; Bowden, Mark E.; Onfroy, Thomas; Dagle, Robert A.

    2016-04-01

    In this study we report on a ZnxZryOz mixed oxide type catalyst capable of converting a syngas-derived C2+ mixed oxygenate feedstock to isobutene-rich olefins. Aqueous model feed comprising of ethanol, acetaldehyde, acetic acid, ethyl acetate, methanol, and propanol was used as representative liquid product derived from a Rh-based mixed oxygenate synthesis catalyst. Greater than 50% carbon yield to C3-C5 mixed olefins was demonstrated when operating at 400-450oC and 1 atm. In order to rationalize formation of the products observed feed components were individually evaluated. Major constituents of the feed mixture (ethanol, acetaldehyde, acetic acid, and ethyl acetate) were found to produce isobutene-rich olefins. C-C coupling was also demonstrated for propanol feedstock - a minor constituent of the mixed oxygenate feed - producing branched C6 olefins, revealing scalability to alcohols higher than ethanol following an analogous reaction pathway. Using ethanol and propanol feed mixtures, cross-coupling reactions produced mixtures of C4, C5, and C6 branched olefins. The presence of H2 in the feed was found to facilitate hydrogenation of the ketone intermediates, thus producing straight chain olefins as byproducts. While activity loss from coking is observed complete catalyst regeneration is achieved by employing mild oxidation. For conversion of the mixed oxygenate feed a Zr/Zn ratio of 2.5 and a reaction temperature of 450oC provides the best balance of stability, activity, and selectivity. X-ray diffraction and scanning transmission electron microscopy analysis reveals the presence of primarily cubic phase ZrO2 and a minor amount of the monoclinic phase, with ZnO being highly dispersed in the lattice. The presence of ZnO appears to stabilize the cubic phase resulting in less monoclinic phase as the ZnO concentration increases. Infrared spectroscopy shows the mixed oxide acid sites are characterized as primarily Lewis type acidity. The direct relationship between

  20. The Applications of Mixed Metal Oxides to Capture the CO2 and Convert to Syn-Gas

    Directory of Open Access Journals (Sweden)

    A. G. Gaikwad

    2015-01-01

    Full Text Available AbstractThe applicationsof different mixed metal oxides were explored for the capture of CO2and convert of CO2 to syn-gas. The several samples of the mixedmetal oxides were prepared by the sol gel, solid-solid fusion, precipitation,molten salt and template methods in order to investigate the performance ofmixed mtal oxides to the CO2 applications. These samples werecalcined for the 3h in air at 900 oC. The mixed metal oxides sampleswere characterized by acidity/ basicity, surface area, XRD pattern, SEM imagesand to capture CO2. The basicity and surface area of the samples of mixedmetal oxides were found to be in the range from 0.7 to 15.7 mmol g-1and 2.24 to 138.76 m2 g-1, respectively. The obtainedresults of prepared mixed metal oxides by different method were compared forthe purpose of searching the efficient materials. The temperature profiles of thecaptured CO2 by the samples of mixed metal oxides were obtained inthe range 100 to 800 oC. The captured CO2 was found to bein the range from 7.36 to 26.93 wt%. The conversions of CO2 bymethane were explored to syn-gas over the mixed metal oxides including the calciumiron lanthanum mixed metal oxides and Pd (5 wt %/Al2O3at 700 oC with the gas hourly space velocities (GHSV 6000 ml h-1g-1 of methane, 6000 ml h-1 g-1 of CO2and 24000 ml h-1 g-1 of helium.

  1. Structure and Catalytic Behavior of CuO-ZrO-CeO2 Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    王恩过; 陈诵英

    2002-01-01

    The effect of doping CuO on the structure and properties of zirconia-ceria mixed oxide was studied. The results show that addition of CuO decreases the reduction temperature of ceria, and stabilizes the cubic structure of mixed oxides, and enhances catalytic activity of CuO-ZrO-CeO2 mixed oxides for CO oxidation. Increasing ceria content in the mixed oxides can enhance the catalytic activity, but some impurities such as sulfate make catalytic activity falling. There is little effect of calcination temperature on catalytic activities, implying that these catalysts are effective with good thermal stability.

  2. Hypochlorous and peracetic acid induced oxidation of dairy proteins.

    Science.gov (United States)

    Kerkaert, Barbara; Mestdagh, Frédéric; Cucu, Tatiana; Aedo, Philip Roger; Ling, Shen Yan; De Meulenaer, Bruno

    2011-02-09

    Hypochlorous and peracetic acids, both known disinfectants in the food industry, were compared for their oxidative capacity toward dairy proteins. Whey proteins and caseins were oxidized under well controlled conditions at pH 8 as a function of the sanitizing concentration. Different markers for protein oxidation were monitored. The results established that the protein carbonyl content was a rather unspecific marker for protein oxidation, which did not allow one to differentiate the oxidant used especially at the lower concentrations. Cysteine, tryptophan, and methionine were proven to be the most vulnerable amino acids for degradation upon hypochlorous and peracetic acid treatment, while tyrosine was only prone to degradation in the presence of hypochlorous acid. Hypochlorous acid induced oxidation gave rise to protein aggregation, while during peracetic acid induced oxidation, no high molecular weight aggregates were observed. Protein aggregation upon hypochlorous acid oxidation could primarily be linked to tryptophan and tyrosine degradation.

  3. Mass transport in mixed conducting perovskite related oxides

    CERN Document Server

    Shaw, C K M

    2001-01-01

    mechanical and chemical stability of LSCN under practical operating temperatures have been measured and related to long term stability in typical SOFC assemblies. The phase stability and the effect of preparation conditions under different atmospheres on La sub 2 Ni sub 1 sub - sub x Co sub x O sub 4 sub + subdelta compounds were examined using high temperature X-ray diffraction. Fast oxygen uptake at low temperatures was observed in these studies indicating rapid oxygen diffusion, which was confirmed by isotope exchange investigations. The oxygen diffusion and surface exchange data obtained from IEDP-SIMS measurements of La sub 2 Ni sub 0 sub . sub 8 Co sub 0 sub . sub 2 O sub 4 sub + subdelta have enabled suppositions to be made regarding the reduction process and aided further interpretation of the defect model for these oxides. Mixed ionic electronic conducting oxides of the perovskite structure have attracted great interest in the field of solid oxide electrochemical devices. Their ability to allow poten...

  4. Transparent conductive electrodes of mixed TiO2−x–indium tin oxide for organic photovoltaics

    KAUST Repository

    Lee, Kyu-Sung

    2012-05-22

    A transparent conductive electrode of mixed titanium dioxide (TiO2−x)–indium tin oxide (ITO) with an overall reduction in the use of indium metal is demonstrated. When used in organic photovoltaicdevices based on bulk heterojunction photoactive layer of poly (3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester, a power conversion efficiency of 3.67% was obtained, a value comparable to devices having sputtered ITO electrode. Surface roughness and optical efficiency are improved when using the mixed TiO2−x–ITO electrode. The consumption of less indium allows for lower fabrication cost of such mixed thin filmelectrode.

  5. Oxidation control of fluxes for mixed-valent inorganic oxide materials synthesis

    Science.gov (United States)

    Schrier, Marc David

    This dissertation is concerned with controlling the flux synthesis and ensuing physical properties of mixed-valence metal oxides. Molten alkali metal nitrates and hydroxides have been explored to determine and exploit their variable redox chemistries for the synthesis of mixed-valent oxide materials. Cationic and anionic additives have been utilized in these molten salts to control the relative concentrations of the redox-active species present to effectively tune and cap the electrochemical potential of the flux. Atoms like bismuth, copper, and manganese are capable of providing different numbers of electrons for bonding. With appropriate doping near the metal-insulator transition, many of these mixed-valent inorganic metal oxides exhibit extraordinary electronic and magnetic properties. Traditionally, these materials have been prepared by classical high temperature solid state routes where microscopic homogeneity is hard to attain. In these routes, the starting composition dictates the doping level, and in turn, the formal oxidation state achieved. Molten flux syntheses developed in this work have provided the potential for preparing single-phase, homogeneous, and crystalline materials. The redox-active fluxes provide a medium for enhanced doping and mixed-valency control in which the electrochemical potential adjusts the formal oxidation state, and the doping takes place to maintain charge neutrality. The two superconductor systems investigated are: (1) the potassium-doped barium bismuth oxides, and (2) the alkali metal- and alkaline earth metal-doped lanthanum copper oxides. Controlled oxidative doping has been achieved in both systems by two different approaches. The superconducting properties of these materials have been assessed, and the materials have been characterized by powder X-ray diffraction and e-beam microprobe elemental analyses. In the course of these studies, several other materials have been identified. Analysis of these materials, and the

  6. Nanoporous composites prepared by a combination of SBA-15 with Mg-Al mixed oxides. Water vapor sorption properties.

    Science.gov (United States)

    Pérez-Verdejo, Amaury; Sampieri, Alvaro; Pfeiffer, Heriberto; Ruiz-Reyes, Mayra; Santamaría, Juana-Deisy; Fetter, Geolar

    2014-01-01

    This work presents two easy ways for preparing nanostructured mesoporous composites by interconnecting and combining SBA-15 with mixed oxides derived from a calcined Mg-Al hydrotalcite. Two different Mg-Al hydrotalcite addition procedures were implemented, either after or during the SBA-15 synthesis (in situ method). The first procedure, i.e., the post-synthesis method, produces a composite material with Mg-Al mixed oxides homogeneously dispersed on the SBA-15 nanoporous surface. The resulting composites present textural properties similar to the SBA-15. On the other hand, with the second procedure (in situ method), Mg and Al mixed oxides occur on the porous composite, which displays a cauliflower morphology. This is an important microporosity contribution and micro and mesoporous surfaces coexist in almost the same proportion. Furthermore, the nanostructured mesoporous composites present an extraordinary water vapor sorption capacity. Such composites might be utilized as as acid-base catalysts, adsorbents, sensors or storage nanomaterials.

  7. Nanoporous composites prepared by a combination of SBA-15 with Mg–Al mixed oxides. Water vapor sorption properties

    Directory of Open Access Journals (Sweden)

    Amaury Pérez-Verdejo

    2014-08-01

    Full Text Available This work presents two easy ways for preparing nanostructured mesoporous composites by interconnecting and combining SBA-15 with mixed oxides derived from a calcined Mg–Al hydrotalcite. Two different Mg–Al hydrotalcite addition procedures were implemented, either after or during the SBA-15 synthesis (in situ method. The first procedure, i.e., the post-synthesis method, produces a composite material with Mg–Al mixed oxides homogeneously dispersed on the SBA-15 nanoporous surface. The resulting composites present textural properties similar to the SBA-15. On the other hand, with the second procedure (in situ method, Mg and Al mixed oxides occur on the porous composite, which displays a cauliflower morphology. This is an important microporosity contribution and micro and mesoporous surfaces coexist in almost the same proportion. Furthermore, the nanostructured mesoporous composites present an extraordinary water vapor sorption capacity. Such composites might be utilized as as acid-base catalysts, adsorbents, sensors or storage nanomaterials.

  8. Bright blue photoluminescence from a mixed tin and manganese oxide xerogel prepared via sol-hydrothermal-gel process

    Institute of Scientific and Technical Information of China (English)

    Xiang Xia; Cheng Xiao-Feng; He Shao-Bo; Yuan Xiao-Dong; Zheng Wan-Guo; Li Zhi-Jie; Liu Chun-Ming; Zhou Wei-Lie; Zu Xiao-Tao

    2011-01-01

    A new blue photoluminescent material,a mixed tin and manganese oxide xerogel,is prepared via sol-hydrothermalgel process assisted by citric acid.The composition xerogel exhibits strong blue emission at room temperature,with an emission maximum at 434 nm under short (234 nm) or long-wavelength (343 nm) ultraviolet excitation.The photoluminescent excitation spectrum of the mixed tin and manganese oxide xerogel,monitored at an intensity maximum wavelength of 434 nm of the emission,consists of two excitation peaks at 234 nm and 343 nm.With heat treatment temperature increasing from 110 ℃ to 200 ℃,the blue emission intensity increases remarkably,whereas it is almost completely quenched after being treated at 300 ℃.The carbon impurities in the mixed tin and manganese oxide xerogel,confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy,should be responsible for the bright blue photoluminescence.

  9. Perovskite-type Mixed Oxides Catalyst for Complete Oxidation of Acetone

    Institute of Scientific and Technical Information of China (English)

    DUAN; ZhiYing

    2001-01-01

    The catalytic oxidation of VOCs (volatile organic compounds) is an attractive subject in the field of environmental protection now. Furthermore, most countries have made out regulations m controlling the maximum content of VOCs in some places. Presently, the leading way of domestic and foreign means to eliminate VOCs is to completely oxidize VOCs into carbon dioxide and water in presence of noble metal catalyst. But noble metal is expensive for lack of resource[2]. So it is insistent to research a low-cost catalyst for removal of VOCs. In this work, we have used some base metals (such as La, Sr, Ce, Ni, Cu) to synthesize mixed oxides catalyst supported on γ-A12O3. We have investigated the catalytic properties in the complete oxidation of acetone over the catalyst prepared and achieved an exciting result.……

  10. Perovskite-type Mixed Oxides Catalyst for Complete Oxidation of Acetone

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ The catalytic oxidation of VOCs (volatile organic compounds) is an attractive subject in the field of environmental protection now. Furthermore, most countries have made out regulations m controlling the maximum content of VOCs in some places. Presently, the leading way of domestic and foreign means to eliminate VOCs is to completely oxidize VOCs into carbon dioxide and water in presence of noble metal catalyst. But noble metal is expensive for lack of resource[2]. So it is insistent to research a low-cost catalyst for removal of VOCs. In this work, we have used some base metals (such as La, Sr, Ce, Ni, Cu) to synthesize mixed oxides catalyst supported on γ-A12O3. We have investigated the catalytic properties in the complete oxidation of acetone over the catalyst prepared and achieved an exciting result.

  11. Properties of mixed molybdenum oxide iridium oxide thin films synthesized by spray pyrolysis

    Science.gov (United States)

    Patil, P. S.; Kawar, R. K.; Sadale, S. B.; Inamdar, A. I.; Deshmukh, H. P.

    2006-09-01

    Molybdenum-doped iridium oxide thin films have been deposited onto corning glass- and fluorine-doped tin oxide coated corning glass substrates at 350 °C by using a pneumatic spray pyrolysis technique. An aqueous solution of 0.01 M ammonium molybdate was mixed with 0.01 M iridium trichloride solution in different volume proportions and the resultant solution was used as a precursor solution for spraying. The as-deposited samples were annealed at 600 °C in air medium for 1 h. The structural, electrical and optical properties of as-deposited and annealed Mo-doped iridium oxide were studied and values of room temperature electrical resistivity, and thermoelectric power were estimated. The as-deposited samples with 2% Mo doping exhibit more pronounced electrochromism than other samples, including pristine Ir oxide.

  12. CATALYTIC HYDROGENATION AND OXIDATION OF BIOMASS-DERIVED LEVULINIC ACID

    Directory of Open Access Journals (Sweden)

    Yan Gong

    2011-02-01

    Full Text Available Levulinic acid (LA, 4-oxo-pentanoic acid, is a new platform chemical with various potential uses. In this paper, catalytic hydrogenation and oxidation of levulinic acid were studied. It was shown from experiments that levulinic acid can be hydrogenated to γ-valerolactone (GVL over transition metal catalysts and oxidative-decarboxylated to 2-butanone (methyl-ethyl-ketone, MEK and methyl-vinyl-ketone (MVK by cupric oxide (CuO, cupric oxide/cerium oxide (CuO/CeO2, cupric oxide/ alumina (CuO/ Al2O3, and silver(I/ peroxydisulfate (Ag(I/S2O82-.

  13. Laser-induced breakdown spectroscopy for determination of uranium in thorium-uranium mixed oxide fuel materials.

    Science.gov (United States)

    Sarkar, Arnab; Alamelu, Devanathan; Aggarwal, Suresh K

    2009-05-15

    Laser-induced breakdown spectroscopy (LIBS) has been developed for determining the percentage of uranium in thorium-uranium mixed oxide fuel samples required as a part of the chemical quality assurance of fuel materials. The experimental parameters were optimized using mixed oxide pellets prepared from 1:1 (w/w) mixture of thorium-uranium mixed oxide standards and using boric acid as a binder. Calibration curves were established using U(II) 263.553 nm, U(II) 367.007 nm, U(II) 447.233 nm and U(II) 454.363 nm emission lines. The uranium amount determined in two synthetic mixed oxide samples using calibration curves agreed well with that of the expected values. Except for U(II) 263.553 nm, all the other emission lines exhibited a saturation effect due to self-absorption when U amount exceeded 20 wt.% in the Th-U mixture. The present method will be useful for fast and routine determination of uranium in mixed oxide samples of Th and U, without the need for dissolution, which is difficult and time consuming due to the refractory nature of ThO(2). The methodology developed is encouraging since a very good analytical agreement was obtained considering the limited resolution of the spectrometer employed in the work.

  14. Characterization of manganese-gallium mixed oxide powders

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Escribano, V.; Fernandez Lopez, E.; Sanchez Huidobro, P. [Universidad de Salamanca, Dept. de Quimica Inorganica (Spain); Panizza, M.; Resini, C.; Busca, G. [UNiversita di Genova, Dipt. di Ingegneria Chimica e di Processo, Genova (Italy); Resini, C. [Istituto Nazionale di Fisica della Materia, INFM (Spain); Gallardo- Amores, J.M. [Universidad Complutense, Dept. de Quimica Inorganica, Lab. Complutense de Altas Presiones, Madrid (Spain)

    2003-12-01

    Mn-Ga mixed oxides have been prepared by coprecipitation of the corresponding oxo-hydroxides as powders and have been characterized in relation to their structural and optical properties. The materials have been characterized by XRD, TG-DTA, skeletal IR and UV-visible-NIR spectroscopies. Large solubility of Mn in the diaspore type {alpha}-GaOOH oxo-hydroxide has been found. The spinel related structures of hausmannite Mn{sub 3}O{sub 4} and of {beta}-gallia present large reciprocal solubilities at least in a metastable form. At high temperature also bixbyite-type {alpha}-Mn{sub O3} solid solutions containing up to 20% at. Ga have been observed. (authors)

  15. Yttrium bismuth titanate pyrochlore mixed oxides for photocatalytic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Merka, Oliver

    2012-10-18

    In this work, the sol-gel synthesis of new non-stoichiometric pyrochlore titanates and their application in photocatalytic hydrogen production is reported. Visible light response is achieved by introducing bismuth on the A site or by doping the B site by transition metal cations featuring partially filled d orbitals. This work clearly focusses on atomic scale structural changes induced by the systematical introduction of non-stoichiometry in pyrochlore mixed oxides and the resulting influence on the activity in photocatalytic hydrogen production. The materials were characterized in detail regarding their optical properties and their atomic structure. The pyrochlore structure tolerates tremendous stoichiometry variations. The non-stoichiometry in A{sub 2}O{sub 3} rich compositions is compensated by distortions in the cationic sub-lattice for the smaller Y{sup 3+} cation and by evolution of a secondary phase for the larger Bi{sup 3+} cation on the A site. For TiO{sub 2} rich compositions, the non-stoichiometry leads to a special vacancy formation in the A and optionally O' sites. It is shown that pyrochlore mixed oxides in the yttrium bismuth titanate system represent very active and promising materials for photocatalytic hydrogen production, if precisely and carefully tuned. Whereas Y{sub 2}Ti{sub 2}O{sub 7} yields stable hydrogen production rates over time, the bismuth richer compounds of YBiTi{sub 2}O{sub 7} and Bi{sub 2}Ti{sub 2}O{sub 7} are found to be not stable under irradiation. This drawback is overcome by applying a special co-catalyst system consisting of a precious metal core and a Cr{sub 2}O{sub 3} shell on the photocatalysts.

  16. Calculational Benchmark Problems for VVER-1000 Mixed Oxide Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Emmett, M.B.

    2000-03-17

    Standard problems were created to test the ability of American and Russian computational methods and data regarding the analysis of the storage and handling of Russian pressurized water reactor (VVER) mixed oxide fuel. Criticality safety and radiation shielding problems were analyzed. Analysis of American and Russian multiplication factors for fresh fuel storage for low-enriched uranium (UOX), weapons- (MOX-W) and reactor-grade (MOX-R) MOX differ by less than 2% for all variations of water density. For shielding calculations for fresh fuel, the ORNL results for the neutron source differ from the Russian results by less than 1% for UOX and MOX-R and by approximately 3% for MOX-W. For shielding calculations for fresh fuel assemblies, neutron dose rates at the surface of the assemblies differ from the Russian results by 5% to 9%; the level of agreement for gamma dose varies depending on the type of fuel, with UOX differing by the largest amount. The use of different gamma group structures and instantaneous versus asymptotic decay assumptions also complicate the comparison. For the calculation of dose rates from spent fuel in a shipping cask, the neutron source for UOX after 3-year cooling is within 1% and for MOX-W within 5% of one of the Russian results while the MOX-R difference is the largest at over 10%. These studies are a portion of the documentation required by the Russian nuclear regulatory authority, GAN, in order to certify Russian programs and data as being acceptably accurate for the analysis of mixed oxide fuels.

  17. Applications of Metal/Mixed Metal Oxides as Photocatalyst: (A Review

    Directory of Open Access Journals (Sweden)

    Avnish Kumar Arora

    2016-08-01

    Full Text Available Metal oxides/ Mixed metal oxides have wide applications as catalyst, Adsorbents, Superconductors, semiconductors, ceramics, antifungal agents and also have spacious applications in medicines. This review article is focused on their applications as photocatalyst in various organic reactions.

  18. Methane combustion over lanthanum-based perovskite mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Arandiyan, Hamidreza [New South Wales Univ., Sydney (Australia). School of Chemical Engineering

    2015-11-01

    This book presents current research into the catalytic combustion of methane using perovskite-type oxides (ABO{sub 3}). Catalytic combustion has been developed as a method of promoting efficient combustion with minimum pollutant formation as compared to conventional catalytic combustion. Recent theoretical and experimental studies have recommended that noble metals supported on (ABO{sub 3}) with well-ordered porous networks show promising redox properties. Three-dimensionally ordered macroporous (3DOM) materials with interpenetrated and regular mesoporous systems have recently triggered enormous research activity due to their high surface areas, large pore volumes, uniform pore sizes, low cost, environmental benignity, and good chemical stability. These are all highly relevant in terms of the utilization of natural gas in light of recent catalytic innovations and technological advances. The book is of interest to all researchers active in utilization of natural gas with novel catalysts. The research covered comes from the most important industries and research centers in the field. The book serves not only as a text for researcher into catalytic combustion of methane, 3DOM perovskite mixed oxide, but also explores the field of green technologies by experts in academia and industry. This book will appeal to those interested in research on the environmental impact of combustion, materials and catalysis.

  19. Poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide)-templated synthesis of mesoporous alumina: effect of triblock copolymer and acid concentration.

    Science.gov (United States)

    Materna, Kelly L; Grant, Stacy M; Jaroniec, Mietek

    2012-07-25

    Mesoporous alumina was synthesized via a one-pot self-assembly of aluminum isopropoxide and poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer in an acidic ethanol solution. The effects of the polymer concentration and nitric acid concentration, independently, on the adsorption properties (such as surface area, pore volume, microporosity, mesoporosity, and pore width) were studied. An increase in the specific surface area and the pore volume was seen for the samples containing a polymer/aluminum isopropoxide wt. ratio up to 0.71 and a polymer/acid wt ratio of 0.88. Titania isopropoxide was also added to the synthesis to illustrate the extension of this approach to alumina-based mixed metal oxides.

  20. An Amino Acid Code for Irregular and Mixed Protein Packing

    Science.gov (United States)

    Joo, Hyun; Chavan, Archana; Fraga, Keith; Tsai, Jerry

    2015-01-01

    To advance our understanding of protein tertiary structure, the development of the knob-socket model is completed in an analysis of the packing in irregular coil and turn secondary structure packing as well as between mixed secondary structure. The knob-socket model simplifies packing based on repeated patterns of 2 motifs: a 3 residue socket for packing within 2° structure and a 4 residue knob-socket for 3° packing. For coil and turn secondary structure, knob-sockets allow identification of a correlation between amino acid composition and tertiary arrangements in space. Coil contributes almost as much as α-helices to tertiary packing. Irregular secondary structure involves 3 residue cliques of consecutive contacting residues or XYZ sockets. In irregular sockets, Gly, Pro, Asp and Ser are favored, while Cys, His, Met and Trp are not. For irregular knobs, the preference order is Arg, Asp, Pro, Asn, Thr, Leu, and Gly, while Cys, His, Met and Trp are not. In mixed packing, the knob amino acid preferences are a function of the socket that they are packing into, whereas the amino acid composition of the sockets does not depend on the secondary structure of the knob. A unique motif of a coil knob with an XYZ β-sheet socket may potentially function to inhibit β-sheet extension. In addition, analysis of the preferred crossing angles for strands within a β-sheet and mixed α-helices/β-sheets identifies canonical packing patterns useful in protein design. Lastly, the knob-socket model abstracts the complexity of protein tertiary structure into an intuitive packing surface topology map. PMID:26370334

  1. Melting behavior of mixed U-Pu oxides under oxidizing conditions

    Science.gov (United States)

    Strach, Michal; Manara, Dario; Belin, Renaud C.; Rogez, Jacques

    2016-05-01

    In order to use mixed U-Pu oxide ceramics in present and future nuclear reactors, their physical and chemical properties need to be well determined. The behavior of stoichiometric (U,Pu)O2 compounds is relatively well understood, but the effects of oxygen stoichiometry on the fuel performance and stability are often still obscure. In the present work, a series of laser melting experiments were carried out to determine the impact of an oxidizing atmosphere, and in consequence the departure from a stoichiometric composition on the melting behavior of six mixed uranium plutonium oxides with Pu content ranging from 14 to 62 wt%. The starting materials were disks cut from sintered stoichiometric pellets. For each composition we have performed two laser melting experiments in pressurized air, each consisting of four shots of different duration and intensity. During the experiments we recorded the temperature at the surface of the sample with a pyrometer. Phase transitions were qualitatively identified with the help of a reflected blue laser. The observed phase transitions occur at a systematically lower temperature, the lower the Pu content of the studied sample. It is consistent with the fact that uranium dioxide is easily oxidized at elevated temperatures, forming chemical species rich in oxygen, which melt at a lower temperature and are more volatile. To our knowledge this campaign is a first attempt to quantitatively determine the effect of O/M on the melting temperature of MOX.

  2. Melting behavior of mixed U–Pu oxides under oxidizing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Strach, Michal [CEA, DEN, DTEC, SECA, LCC, Cadarache F-13108, Saint-Paul-Lez-Durance (France); IM2NP, UMR CNRS 7334 – Aix Marseille University, Case 251, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France); Manara, Dario [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Belin, Renaud C. [CEA, DEN, DTEC, SECA, LCC, Cadarache F-13108, Saint-Paul-Lez-Durance (France); Rogez, Jacques [IM2NP, UMR CNRS 7334 – Aix Marseille University, Case 251, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France)

    2016-05-01

    In order to use mixed U–Pu oxide ceramics in present and future nuclear reactors, their physical and chemical properties need to be well determined. The behavior of stoichiometric (U,Pu)O{sub 2} compounds is relatively well understood, but the effects of oxygen stoichiometry on the fuel performance and stability are often still obscure. In the present work, a series of laser melting experiments were carried out to determine the impact of an oxidizing atmosphere, and in consequence the departure from a stoichiometric composition on the melting behavior of six mixed uranium plutonium oxides with Pu content ranging from 14 to 62 wt%. The starting materials were disks cut from sintered stoichiometric pellets. For each composition we have performed two laser melting experiments in pressurized air, each consisting of four shots of different duration and intensity. During the experiments we recorded the temperature at the surface of the sample with a pyrometer. Phase transitions were qualitatively identified with the help of a reflected blue laser. The observed phase transitions occur at a systematically lower temperature, the lower the Pu content of the studied sample. It is consistent with the fact that uranium dioxide is easily oxidized at elevated temperatures, forming chemical species rich in oxygen, which melt at a lower temperature and are more volatile. To our knowledge this campaign is a first attempt to quantitatively determine the effect of O/M on the melting temperature of MOX.

  3. Reaction pathways for catalytic gas-phase oxidation of glycerol over mixed metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Suprun, W.; Glaeser, R.; Papp, H. [Leipzig Univ. (Germany). Inst. of Chemical Technology

    2011-07-01

    Glycerol as a main by-product from bio-diesel manufacture is a cheap raw material with large potential for chemical or biochemical transformations to value-added C3-chemicals. One possible way of glycerol utilization involves its catalytic oxidation to acrylic acid as an alternative to petrochemical routes. However, this catalytic conversion exhibits various problems such as harsh reaction conditions, severe catalyst coking and large amounts of undesired by-products. In this study, the reaction pathways for gas-phase conversion of glycerol over transition metal oxides (Mo, V und W) supported on TiO{sub 2} and SiO{sub 2} were investigated by two methods: (i) steady state experiments of glycerol oxidation and possible reactions intermediates, i.e., acrolein, 3-hydroxy propionaldehyde and acetaldehyde, and (ii) temperature-programmed surface reaction (TPSR) studies of glycerol conversion in the presence and in the absence of gas-phase oxygen. It is shown that the supported W-, V and Mo-oxides possess an ability to catalyze the oxidation of glycerol to acrylic acid. These investigations allowed us to gain a deeper insight into the reaction mechanism. Thus, based on the obtained results, three possible reactions pathways for the selective oxidation of glycerol to acrylic acid on the transition metal-containing catalysts are proposed. The major pathways in presence of molecular oxygen are a fast successive destructive oxidation of glycerol to CO{sub x} and the dehydration of glycerol to acrolein which is a rate-limiting step. (orig.)

  4. Mixed micelles of 7,12-dioxolithocholic acid and selected hydrophobic bile acids: interaction parameter, partition coefficient of nitrazepam and mixed micelles haemolytic potential.

    Science.gov (United States)

    Poša, Mihalj; Tepavčević, Vesna

    2011-09-01

    The formation of mixed micelles built of 7,12-dioxolithocholic and the following hydrophobic bile acids was examined by conductometric method: cholic (C), deoxycholic (D), chenodeoxycholic (CD), 12-oxolithocholic (12-oxoL), 7-oxolithocholic (7-oxoL), ursodeoxycholic (UD) and hiodeoxycholic (HD). Interaction parameter (β) in the studied binary mixed micelles had negative value, suggesting synergism between micelle building units. Based on β value, the hydrophobic bile acids formed two groups: group I (C, D and CD) and group II (12-oxoL, 7-oxoL, UD and HD). Bile acids from group II had more negative β values than bile acids from group I. Also, bile acids from group II formed intermolecular hydrogen bonds in aggregates with both smaller (2) and higher (4) aggregation numbers, according to the analysis of their stereochemical (conformational) structures and possible structures of mixed micelles built of these bile acids and 7,12-dioxolithocholic acid. Haemolytic potential and partition coefficient of nitrazepam were higher in mixed micelles built of the more hydrophobic bile acids (C, D, CD) and 7,12-dioxolithocholic acid than in micelles built only of 7,12-dioxolithocholic acid. On the other hand, these mixed micelles still had lower values of haemolytic potential than micelles built of C, D or CD. The mixed micelles that included bile acids: 12-oxoL, 7-oxoL, UD or HD did not significantly differ from the micelles of 7,12-dioxolithocholic acid, observing the values of their haemolytic potential.

  5. Kinetics of wet air oxidation of glyoxalic acid and oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Mahajani, V.V. (Univ. of Bombay (India). Dept. of Chemical Technology)

    1994-12-01

    Oxidation of lower molecular weight monobasic and dibasic acids such as formic acid, acetic acid, glyoxalic acid, and oxalic acid is often the rate-controlling step during wet air oxidation (WAO) of an aqueous waste stream exhibiting very high chemical oxygen demand (COD). The kinetics of WAO of glyoxalic acid and oxalic acid was studied in absence and presence of a cupric sulfate catalyst in the temperature range of 120--245 C and oxygen partial pressure of 0.345--1.380 MPa. The wet oxidation of oxalic acid was found to require more severe conditions as compared to glyoxalic acid. The reaction mechanism and kinetic model have been discussed.

  6. Highly stable, mesoporous mixed lanthanum-cerium oxides with tailored structure and reducibility

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Shuang; Broitman, Esteban; Wang, Yanan; Cao, Anmin; Veser, Goetz

    2011-05-01

    Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for lanthanum contents as high as 90%. Varying the La:Ce ratio not only allows tailoring of the oxide morphology (lattice parameter, pore structure, particle size, and surface area), but also results in a fine-tuning of the reducibility of the oxide which can be explained by the creation of oxygen vacancies in the ceria lattice upon La addition. Such finely controlled syntheses, which enable the formation of stable, homogeneous mixed oxides across the entire composition range, open the path towards functional tailoring of oxide materials, such as rational catalyst design via fine-tuning of redox activity.

  7. Mixed fuel strategy for carbon deposition mitigation in solid oxide fuel cells at intermediate temperatures.

    Science.gov (United States)

    Su, Chao; Chen, Yubo; Wang, Wei; Ran, Ran; Shao, Zongping; Diniz da Costa, João C; Liu, Shaomin

    2014-06-17

    In this study, we propose and experimentally verified that methane and formic acid mixed fuel can be employed to sustain solid oxide fuel cells (SOFCs) to deliver high power outputs at intermediate temperatures and simultaneously reduce the coke formation over the anode catalyst. In this SOFC system, methane itself was one part of the fuel, but it also played as the carrier gas to deliver the formic acid to reach the anode chamber. On the other hand, the products from the thermal decomposition of formic acid helped to reduce the carbon deposition from methane cracking. In order to clarify the reaction pathways for carbon formation and elimination occurring in the anode chamber during the SOFC operation, O2-TPO and SEM analysis were carried out together with the theoretical calculation. Electrochemical tests demonstrated that stable and high power output at an intermediate temperature range was well-maintained with a peak power density of 1061 mW cm(-2) at 750 °C. With the synergic functions provided by the mixed fuel, the SOFC was running for 3 days without any sign of cell performance decay. In sharp contrast, fuelled by pure methane and tested at similar conditions, the SOFC immediately failed after running for only 30 min due to significant carbon deposition. This work opens a new way for SOFC to conquer the annoying problem of carbon deposition just by properly selecting the fuel components to realize their synergic effects.

  8. Thermal Hazard Evaluation of Lauroyl Peroxide Mixed with Nitric Acid

    Directory of Open Access Journals (Sweden)

    Chi-Min Shu

    2012-07-01

    Full Text Available Many thermal runaway incidents have been caused by organic peroxides due to the peroxy group, –O–O–, which is essentially unstable and active. Lauroyl peroxide (LPO is also sensitive to thermal sources and is incompatible with many materials, such as acids, bases, metals, and ions. From the thermal decomposition reaction of various concentrations of nitric acid (HNO3 (from lower to higher concentrations with LPO, experimental data were obtained as to its exothermic onset temperature (T0, heat of decomposition (ΔHd, isothermal time to maximum rate (TMRiso, and other safety parameters exclusively for loss prevention of runaway reactions and thermal explosions. As a novel finding, LPO mixed with HNO3 can produce the detonation product of 1-nitrododecane. We used differential scanning calorimetry (DSC, thermal activity monitor III (TAM III, and gas chromatography/mass spectrometer (GC/MS analyses of the reactivity for LPO and itself mixed with HNO3 to corroborate the decomposition reactions and reaction mechanisms in these investigations.

  9. Microbial Ecology Assessment of Mixed Copper Oxide/Sulfide Dump Leach Operation

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, D F; Thompson, D N; Noah, K S

    1999-06-01

    Microbial consortia composed of complex mixtures of autotrophic and heterotrophic bacteria are responsible for the dissolution of metals from sulfide minerals. Thus, an efficient copper bioleaching operation depends on the microbial ecology of the system. A microbial ecology study of a mixed oxide/sulfide copper leaching operation was conducted using an "overlay" plating technique to differentiate and identify various bacterial consortium members of the genera Thiobacillus, Leptospirillum, Ferromicrobium, and Acidiphilium. Two temperatures (30C and 45C) were used to select for mesophilic and moderately thermophilic bacteria. Cell numbers varied from 0-106 cells/g dry ore, depending on the sample location and depth. After acid curing for oxide leaching, no viable bacteria were recovered, although inoculation of cells from raffinate re-established a microbial population after three months. Due to the low pH of the operation, very few non-iron-oxidizing acidophilic heterotrophs were recovered. Moderate thermophiles were isolated from the ore samples. Pregnant liquor solutions (PLS) and raffinate both contained a diversity of bacteria. In addition, an intermittently applied waste stream that contained high levels of arsenic and fluoride was tested for toxicity. Twenty vol% waste stream in PLS killed 100% of the cells in 48 hours, indicating substantial toxicity and/or growth inhibition. The data indicate that bacteria populations can recover after acid curing, and that application of the waste stream to the dump should be avoided. Monitoring the microbial ecology of the leaching operation provided significant information that improved copper recovery.

  10. Different Abilities of Eight Mixed Cultures of Methane-oxidizing Bacteria to Degrade TCE

    DEFF Research Database (Denmark)

    Broholm, Kim; Christensen, Thomas Højlund; Jensen, Bjørn K.

    1993-01-01

    The ability of eight mixed cultures of methane-oxidizing bacteria to degrade trichloroethylene (TCE) was examined in laboratory batch experiments. This is one of the first reported works studying TCE degradation by mixed cultures of methane-oxidizing bacteria at 10°C, a common temperature for soils...

  11. 76 FR 65544 - Standard Format and Content of License Applications for Mixed Oxide Fuel Fabrication Facilities

    Science.gov (United States)

    2011-10-21

    ... issuance of the guide (74 FR 36780). The comment period closed on September 21, 2009. The staff's responses... COMMISSION Standard Format and Content of License Applications for Mixed Oxide Fuel Fabrication Facilities... Format and Content of License Applications for Mixed Oxide Fuel Fabrication Facilities.'' This...

  12. wet oxidation of maleic acid by a pumice supported copper

    African Journals Online (AJOL)

    Mgina

    materials were tested in a wet oxidation of maleic acid using air or hydrogen peroxide as an oxidant. Results ... textile, pharmaceuticals, paper and pulp .... Fourier Transform Infrared (FTIR). The ... to analysis and then run at room temperature.

  13. Advanced oxidation of acid and reactive dyes

    DEFF Research Database (Denmark)

    Arslan-Alaton, I.; Gursoy, B.H.; Schmidt, Jens Ejbye

    2008-01-01

    M) for 10:hsp sp="0.25" min Fenton treatment at pH 3, resulting in reduced chemical oxygen demand and dissolved organic carbon removal efficiencies; only acetate was detected as a stable dye oxidation end product. During anaerobic digestion, 100, 29% and no inhibition in methane production was observed...... for the untreated blue, red and orange dyes, respectively. The inhibitory effect of the blue reactive dye on methane production was ∼21% after Fenton treatment. Neither untreated nor treated dyes exhibited an inhibitory effect on denitrification. Aerobic glucose degradation was inhibited by 23-29% by untreated dyes......The effect of untreated and Fenton-treated acid dyes (C.I. Acid Red 183 and C.I. Acid Orange 51) and a reactive dye (C.I. Reactive Blue 4) on aerobic, anoxic and anaerobic processes was investigated. The optimum Fe2+:H2O2 molar ratio was selected as 1:5 (4:hsp sp="0.25" mM:20:hsp sp="0.25"m...

  14. Co-Al Mixed Oxides Prepared via LDH Route Using Microwaves or Ultrasound: Application for Catalytic Toluene Total Oxidation

    Directory of Open Access Journals (Sweden)

    Eric Genty

    2015-05-01

    Full Text Available Co6Al2HT hydrotalcite-like compounds were synthesized by three different methods: co-precipitation, microwaves-assisted and ultrasound-assisted methods. The mixed oxides obtained after calcination were studied by several techniques: XRD, TEM, H2-TPR and XPS. They were also tested as catalysts in the reaction of total oxidation of toluene. The physico-chemical studies revealed a modification of the structural characteristics (surface area, morphology as well as of the reducibility of the formed mixed oxides. The solid prepared by microwaves-assisted synthesis was the most active. Furthermore, a relationship between the ratio of Co2+ on the surface, the reducibility of the Co-Al mixed oxide and the T50 in toluene oxidation was demonstrated. This suggests a Mars Van Krevelen mechanism for toluene total oxidation on these catalysts.

  15. Novel mesoporous mixed Nb-M (M = V, Mo, and Sb) oxides for oxidative dehydrogenation of propane.

    Science.gov (United States)

    Yuan, Li; Bhatt, Salil; Beaucage, Gregory; Guliants, Vadim V; Mamedov, Sergey; Soman, Rajiv S

    2005-12-15

    Novel thermally stable mesoporous mixed metal Nb-M (M = V, Mo and Sb) oxides were synthesized in the presence of a nonionic Pluronic P123 surfactant. These oxides displayed promising pore structures and chemical compositions for selective oxidative functionalization of propane: high surface areas (up to 200 m2/g), large pore sizes (5-14 nm), and high pore volumes (up to 0.46 cm3/g). The oxidative dehydrogenation of propane to propylene over mesoporous mixed metal Nb-M oxides employed as a probe reaction suggested that the M component was dispersed as the molecular surface species and also formed a solid solution with NbOx in the inorganic walls of these mesoporous mixed metal oxides.

  16. Molten salt oxidation of mixed waste: Preliminary bench-scale experiments without radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Haas, P.A.; Rudolph, J.C.; Bell, J.T.

    1994-06-01

    Molten salt oxidation (MSO) is a process in which organic wastes are oxidized by sparging them with air through a bed of molten sodium carbonate (bp 851 {degrees}C) at {ge} 900{degrees}C. This process is readily applicable to the mixed waste because acidic products from Cl, S, P, etc., in the waste, along with most metals and most radionuclides, are retained within the melt as oxides or salts. Rockwell International has studied the application of MSO to various wastes, including some mixed waste. A unit used by Rockwell to study the mixed waste treatment is presently in use at Oak Ridge National Laboratory (ORNL). ORNL`s studies to date have concentrated on chemical flowsheet questions. Concerns that were studied included carbon monoxide (CO) emissions, NO{sub x}, emissions, and metal retention under a variety of conditions. Initial experiments show that CO emissions increase with increasing NaCl content in the melt, increasing temperature, and increasing airflow. Carbon monoxide content is especially high (> 2000 ppm) with high chlorine content (> 10%). Thermal NO{sub x}, emissions are relatively low ( < 5 ppm) at temperatures < 1000{degrees}C. However, most (85--100%) of the nitrogen in the feed as organic nitrate or amine was released as NO{sub x}, The metal contents of the melt and of knockout pot samples of condensed salt show high volatilities of Cs as CsCl. Average condensed salt concentrations were 60% for barium and 100% for strontium and cobalt. The cerium disappeared -- perhaps from deposition on the alumina reactor walls.

  17. Preparation of Mixed Perovskite Oxides for Blue-Green Lasers

    Science.gov (United States)

    1984-02-01

    higher for oxide or fluoride . 𔃽. A high radiative lifetime and high fluorescent quantum yield for Ce or the rare earth are desirable. 3 + 4...for all of our single crystal -4- preparations are lanthanum oxide (La„0 ), aluminum oxide (Al^O^) , scandium oxide (Sc„0-.) , and cerium oxide (Ce...crystal material is highly important. Ideally, oxides should be grown in O2, fluorides in ?„, and so forth in order to prevent defects such as

  18. Characterisation of Fe-Cr-Al mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo Amores, J.M. [Universidad Complutense de Madrid (Spain). Dept. de Quimica Inorg.; Sanchez Escribano, V. [Departamento de Quimica Inorganica, Universidad, Salamanca (Spain); Busca, G. [Istituto di Chimica, Facolta di Ingegneria, Universita, P.le J.F. Kennedy, I-16129, Genova (Italy)

    1999-08-16

    Several samples of iron chromium aluminium mixed oxides with different composition have been prepared by coprecipitation at controlled pH starting from the corresponding nitrate salts and following dried at 393 K and calcination at 673 K for 3 h and 1173 K for 3 h. The powders have been characterised by XRD, FT-IR and DR UV-Vis spectroscopies, DTA-TG thermal analyses and measurements of BET surface area. It has been found alumina is soluble into {alpha}-FeCrO{sub 3} phase up to near 20%. These samples are stable at 1243 K with a relative high specific surface area. The {gamma},{theta}{yields}{alpha} phase transition is shifted towards higher temperatures by increasing Al content, being not detectable when {alpha}-FeCrO{sub 3} phase is the main phase. Surface chromates species are identified by the different techniques used and their amount seem to depend directly on the specific surface area of each sample. (orig.) 36 refs.

  19. Investigation of the Carbon Monoxide Gas Sensing Characteristics of Tin Oxide Mixed Cerium Oxide Thin Films

    Directory of Open Access Journals (Sweden)

    Muhammad B. Haider

    2012-02-01

    Full Text Available Thin films of tin oxide mixed cerium oxide were grown on unheated substrates by physical vapor deposition. The films were annealed in air at 500 °C for two hours, and were characterized using X-ray photoelectron spectroscopy, atomic force microscopy and optical spectrophotometry. X-ray photoelectron spectroscopy and atomic force microscopy results reveal that the films were highly porous and porosity of our films was found to be in the range of 11.6–21.7%. The films were investigated for the detection of carbon monoxide, and were found to be highly sensitive. We found that 430 °C was the optimum operating temperature for sensing CO gas at concentrations as low as 5 ppm. Our sensors exhibited fast response and recovery times of 26 s and 30 s, respectively.

  20. Effect of key parameters on the selective acid leach of nickel from mixed nickel-cobalt hydroxide

    Science.gov (United States)

    Byrne, Kelly; Hawker, William; Vaughan, James

    2017-01-01

    Mixed nickel-cobalt hydroxide precipitate (MHP) is a relatively recent intermediate product in primary nickel production. The material is now being produced on a large scale (approximately 60,000 t/y Ni as MHP) at facilities in Australia (Ravensthorpe, First Quantum Minerals) and Papua New Guinea (Ramu, MCC/Highlands Pacific). The University of Queensland Hydrometallurgy research group developed a new processing technology to refine MHP based on a selective acid leach. This process provides a streamlined route to obtaining a high purity nickel product compared with conventional leaching / solvent extraction processes. The selective leaching of nickel from MHP involves stabilising manganese and cobalt into the solid phase using an oxidant. This paper describes a batch reactor study investigating the timing of acid and oxidant addition on the rate and extent of nickel, cobalt, manganese leached from industrial MHP. For the conditions studied, it is concluded that the simultaneous addition of acid and oxidant provide the best process outcomes.

  1. Removing Oscillatoria and Humic Acid from Mixed Water by Potassium Ferrate(Ⅵ) Pre-oxidation and Co-coagulation%K2FeO4预氧化复合絮凝处理颤藻和腐殖酸混合水

    Institute of Scientific and Technical Information of China (English)

    赵春禄; 刘琰

    2011-01-01

    采用K2FeO4预氧化复合高岭土和聚合氯化铝(PAC)混凝处理了含颤藻和腐殖酸的混合水,并探讨了对处理后水中残留铝含量及其形态分布的影响.结果表明:投加4.0 mg·L-1K2FeO4预氧化就能使混合水样的浊度、腐殖酸和藻类的去除率分别达到94.05%、91.67%和90.78%,明显优于相同条件下单纯的PAC处理效果;水样的pH值对K2FeO4预氧化有显著的影响,在pH=6.5时效果最好;K2FeO4预氧化影响处理后水中残留铝的含量和形态,在最佳条件下总铝浓度降低了51.8%,特别是对人体毒害作用最大的溶解态铝降低了43.9%.%The mixed water containing Oscillatoria and humic acid was disposed by using potassium ferrate(Ⅵ) as the pre-oxidation agent, poly-aluminum chloride(PAC) and Kaolin as the co-coagulation agents. The residual aluminum morphology was also studied.The consequence was that the ferrate concentration with 4.0 mg· L-1 could improve the removal rate of turbidity, HA and algae, whose value was 94.05%, 91.67% and 90. 78% respectively, and the effect was much better than PAC singly. The pH value affected the efficiency of ferrate pre-oxidation processing mixed water. In acidic condition (pH = 6. 5) the effect was best. Potassium ferrate(Ⅵ) pre-oxidation affected the content and form of residual aluminum. Under the best condition the total aluminum concentration reduced by 51.8%, and especially the dissolved aluminum which poisoned human body decreased by 43.9%.

  2. Catalytic wet air oxidation with Ni- and Fe-doped mixed oxides derived from hydrotalcites.

    Science.gov (United States)

    Ovejero, G; Rodríguez, A; Vallet, A; Gómez, P; García, J

    2011-01-01

    Catalytic wet air oxidation of Basic Yellow 11 (BY11), a basic dye, was studied in a batch reactor. Layered double hydroxides with the hydrotalcite-like structure containing nickel or iron cations have been prepared by coprecipitation and subsequently calcined leading to Ni- and Fe-doped mixed oxides, respectively. Compared with the results in the wet air oxidation of BY11, these catalysts showed high activity for total organic carbon (TOC), toxicity and dye removal at 120 degrees C and 50 bars after 120 min. It has been demonstrated that the activity depended strongly on the presence of catalyst. The results show that catalysts containing nickel provide a higher extent of oxidation of the dye whereas the reaction carried out with the iron catalyst is faster. The Ni and Fe dispersion determined from the TPR results was higher for the catalysts with a lower Ni or Fe content and decreased for higher Ni or Fe contents. On the basis of activity and selectivity, the Ni containing catalyst with the medium (3%) Ni content was found to be the best catalyst. Finally, a relationship between metal content of the catalyst and reaction rate has been established.

  3. Synthesis of cadmium sulphide in pure and mixed Langmuir-Blodgett films of -octadecylsuccinic acid

    Indian Academy of Sciences (India)

    G Hemakanthi; Balachandran Unni Nair; Aruna Dhathathreyan

    2000-04-01

    Cadmium sulphide (CdS) nanoparticles were grown by the reaction of sodium sulphide (Na2S) with Langmuir-Blodgett (LB) films of cadmium salts of -octadecylsuccinic acid (ODSU) and with LB films of ODSU in mixtures of octadecylamine and octadecyl alcohol. The results indicate that heterogeneous nucleation and aggregation in the pure ODSU LB films due to processes like Ostwald ripening are destabilized by the presence of the long-chain amine and alcohol in mixed systems. CdS nanoparticles in the LB films were monitored by UV-visible absorption spectra, which allow an estimation of the size of the particles. The morphology, size and nature of the nanocrystallites formed depend on whether the sulphidation was done on the pure film or in the mixed films. It is seen that particles of size around 1.6 nm were formed in ODSU/octadecylalcohol and ODSU/octadecylamine mixed LB films while in pure ODSU films the size was about 2.7 nm. These films showed typical needle-shaped structures, as observed by the optical microscopic technique. Mean size and morphology were confirmed by transmission and scanning electron microscopy, while selective area electron diffraction patterns showed six-fold symmetry and indicated that the CdS crystals grow epitaxially with respect to the monolayer. Further, the crystallisation enhanced in the mixed LB films showed a characteristic zinc oxide (Wurtzite) structure compared with the pure ODSU matrix.

  4. Oxidative stabilization of mixed mayonnaises made with linseed oil and saturated medium-chain triglyceride oil

    DEFF Research Database (Denmark)

    Raudsepp, Piret; Brüggemann, Dagmar A.; Lenferink, Aufried;

    2014-01-01

    Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during stor...... simply diluting unsaturated triglycerides with saturated triglycerides is causing the oxidative stabilization observed for mixed mayonnaise and mixed oil mayonnaise. © 2013 Elsevier Ltd. All rights reserved.......Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during...... storage was lower in mixed mayonnaise compared to LSO mayonnaise, while in mixed oil mayonnaise the level of peroxides was constantly low. Mixed oil mayonnaise had a lower rate of oxygen consumption than mixed mayonnaise, LSO mayonnaise having the highest rate. The decay of water-soluble nitroxyl radicals...

  5. Effect of Sr on the properties of Ce–Zr–La mixed oxides

    Directory of Open Access Journals (Sweden)

    RICHUAN RAO

    2006-03-01

    Full Text Available Ce–Zr–La–Sr mixed oxides, with different Sr contents, were prepared by the sol–gel method. In a flow-system microreactor, the reduction properties and the oxygen storage capacity (OSC of the Ce–Zr–La–Sr mixed oxides were investigated by a temperature programmed reduction (TPR and a pulse technique. It was shown that the properties of the Ce–Zr–La mixed oxides depend on the Sr content and that the optimum Sr content in the Ce–Zr–La–Sr mixed oxide is 3 mol%. The Ce–Zr–La–Sr mixed oxides doped with 3 mol% Sr (Ce0.52Zr0.4La0.05Sr0.03O1.945 has the largest specific surface area and better reduction properties and oxygen storage capacity in comparison to the other investigated samples. The XRD results of the Ce–Zr–La–Sr mixed oxides showed that their X-ray diffraction patterns are well in agreement with that of fluorite-type CeO2 with Sr ions incorporated into the Ce–Zr–La mixed oxide structures. With increasing calcination temperature, the intensity of the X-ray diffraction peaks increased, but no new peaks were observed. All of these indicate that the synthesized samples had good thermal stability.

  6. Kinetics of wet oxidation of propionic and 3-hydroxypropionic acids

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Levec, J. [National Inst. of Chemistry, Ljubljana (Slovenia). Lab. for Catalysis and Chemical Reaction Engineering]|[Univ. of Ljubljana (Slovenia). Dept. of Chemical Engineering

    1999-07-01

    Oxidation of aqueous solutions of 3-hydroxypropionic (3-HPA) and propionic acids (PA) was studied in a titanium high-pressure reactor at 280--310 C using oxygen partial pressures between 10 and 45 bar. Oxidation of both acids was found to obey first-order kinetic with respect to their concentrations as well as to their lumped TOC concentrations. Oxidation rate revealed a half order dependence with respect to oxygen for oxidation of both acids. In the case of 3-HPA oxidation, the activation energy was found to be 135 kJ/mol, and it was 140 kJ/mol when lumped concentration TOC was used. The activation energy for PA oxidation is 150 kJ/mol, and it is slightly higher, 158 kJ/mol, for TOC reduction. Almost complete conversion of 3-HPA was achieved at 300 C after 1 h, whereas 95% conversion of PA acid was obtained at 310 C after 3 h. During oxidation of 3-HPA, 3-oxopropionic and acetic acids were identified as intermediate products. Oxidation of PA yielded acetic and formic acids as intermediates; at oxygen partial pressures above 25 bar and 310 C, the formation of acetic acid was appreciably reduced. In both cases, however, direct oxidation to carbon dioxide and water was found to be the main reaction route.

  7. Synthesis and characterization of composites of mixed oxides of iron and neodymium in polymer matrix of aniline–formaldehyde

    Indian Academy of Sciences (India)

    Sajdha; H N Sheikh; B L Kalsotra; N Kumar; S Kumar

    2011-07-01

    Nanocomposites of mixed oxides of iron and neodymium in polymer matrix of anilineformaldehyde are reported. The composites have been obtained by treating the aqueous solution of aniline, hydrochloric acid and formaldehyde with halide of iron and neodymium oxide. The infra-red spectra show broad peaks at ∼ 590 cm-1 and at ∼ 610 cm-1 due to the presence of oxides of both iron and neodymium. In heated samples, the absorption peaks due to metal oxides are better resolved. A broad and strong peak in XRD spectra at 2 value of 35.69920 corresponds to spinel -Fe2O3. 57Fe Mössbauer spectrum for unheated sample gives Mössbauer parameters, i.e. isomer shift (), quadrupole splitting ( ) and effective magnetic field (Heff). Transmission electron microscopy (TEM) micrographs reveal well dispersed particles at different magnifications. Vibrating sample magnetometry (VSM) studies indicate that the ferrite nanoparticles exhibit characteristics of ferromagnetism.

  8. Efficient room temperature oxidation of cyclohexane over highly active hetero-mixed WO3/V2O5 oxide catalyst

    CSIR Research Space (South Africa)

    Makgwane, PR

    2014-09-01

    Full Text Available An efficient room temperature catalyzed oxidation of cyclohexane to cyclohexanone (K) and cyclohexanol (A) was achieved over hetero-mixed tungsten–vanadia (WO(sub3)/V(sub2)O(sub5)) using H(sub2)O(sub2) oxidant. WO(sub3)/V(sub2)O(sub5) exhibited high...

  9. Ozone oxidation of oleic acid surface films decreases aerosol cloud condensation nuclei activity

    Science.gov (United States)

    Schwier, A. N.; Sareen, N.; Lathem, T. L.; Nenes, A.; McNeill, V. F.

    2011-08-01

    Heterogeneous oxidation of aerosols composed of pure oleic acid (C18H34O2, an unsaturated fatty acid commonly found in continental and marine aerosol) by gas-phase O3 is known to increase aerosol hygroscopicity and activity as cloud condensation nuclei (CCN). Whether this trend is preserved when the oleic acid is internally mixed with other electrolytes is unknown and addressed in this study. We quantify the CCN activity of sodium salt aerosols (NaCl and Na2SO4) internally mixed with sodium oleate (SO) and oleic acid (OA). We find that particles containing roughly one monolayer of SO/OA show similar CCN activity to pure salt particles, whereas a tenfold increase in organic concentration slightly depresses CCN activity. O3 oxidation of these multicomponent aerosols has little effect on the critical diameter for CCN activation for unacidified particles at all conditions studied, and the activation kinetics of the CCN are similar in each case to those of pure salts. SO-containing particles which are acidified to atmospherically relevant pH before analysis in order to form oleic acid, however, show depressed CCN activity upon oxidation. This effect is more pronounced at higher organic concentrations. The behavior after oxidation is consistent with the disappearance of the organic surface film, supported by Köhler Theory Analysis (KTA). The κ-Köhler calculations show a small decrease in hygroscopicity after oxidation. The important implication of this finding is that oxidative aging may not always enhance the hygroscopicity of internally mixed inorganic-organic aerosols.

  10. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    Directory of Open Access Journals (Sweden)

    B.Syama Sundar

    2014-06-01

    Full Text Available Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation with Mn (VII in case of DL-Mandelic acid. The following order of reactivity is observed: DL-Mandelic acid > Phenyl acetic acid. The high reactivity of DL-Mandelic acid over phenyl acetic acid may be due to different mechanisms operating with the two substrates and benzaldehyde is the final product in both the cases.

  11. Catalytic performance for methane combustion of supported Mn-Ce mixed oxides

    Institute of Scientific and Technical Information of China (English)

    SHI Limin; CHU Wei; QU Fenfen; HU Jinyan; LI Minmin

    2008-01-01

    A series of supported Mn-Ce mixed oxide catalysts were prepared by the impregnation method and used for the oxidation of methane. The catalysts were characterized by N2 adsorption (BET), X-ray diffraction (XRD), laser Raman spectrum (LRS), and temperature programmed reduction (TPR) techniques. The XRD and LRS results confirmed the high dispersion of active components or formation of solid solution between manganese and cerium oxides in the bulk and on the surface of mixed oxide catalysts. The reducibility was remarka-bly promoted by the stronger synergistic interaction between the two oxides from H2-TPR measurements. As expected, all the experimental mixed oxide catalysts showed excellent activity for methane combustion at low temperature. Especially, for the catalyst with Mn-Ce ratio 3:7, methane conversion reached 92% at a temperature as low as 470 ℃.

  12. Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Pantoya, M; Jr., J S; Zhao, L; Shea, K; Simpson, R; Clapsaddle, B

    2003-11-18

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of these metal oxide/silicon oxide nanocomposites and their performance as energetic materials will be discussed.

  13. Ce-Fe-O mixed oxide as oxygen carrier for the direct partial oxidation of methane to syngas

    Institute of Scientific and Technical Information of China (English)

    魏永刚; 王华; 李孔斋

    2010-01-01

    The Ce-Fe-O mixed oxide with a ratio of Ce/Fe=7:3, which was prepared by coprecipitation method and employed as oxygen carrier, for direct partial oxidation of methane to syngas in the absence of gaseous oxygen was explored. The mixed oxide was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the catalytic performances were studied in a fixed-bed quartz reactor and a thermogravimetric reactor, respectively. Approximately 99.4% H2 se...

  14. Properties of TiO2-SiO2 Mixed Oxides and Photocatalytic Oxidation of Heptane and Sulfur Dioxide

    Institute of Scientific and Technical Information of China (English)

    XIE Chao; XU Zi-li; YANG Qiu-jing; LI Na; WANG De-bao; DU Yao-guo

    2005-01-01

    A series of TiO2-XSiO2[X denotes the molar fraction(%) of silica in the mixed oxides] with different n(Ti)/n(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were characterized by XRD, thermal analysis, FTIR, UV-Vis and SPS. The characterization results of FTIR and UV-Vis spectra show that Ti atoms were gradually changed from octahedral coordination to tetrahedral coordination with the addition of silica, which is not beneficial for obtaining strong Brnsted acidity and higher photocatalytic activity. The photocatalytic activity experiments, which were conducted by using heptane(or SO2) as the model reactant, showed that TiO2-SiO2 containing a suitable amount of silica can exhibit much higher photocatalytic activity than pure TiO2. The enhanced photocatalytic activity can be attributed to three following factors: (1) smaller crystalline size; (2) higher thermal stability; (3) the new strong Brnsted acidity.

  15. Mixing-controlled uncertainty in long-term predictions of acid rock drainage from heterogeneous waste-rock piles

    Science.gov (United States)

    Pedretti, D.; Beckie, R. D.; Mayer, K. U.

    2015-12-01

    The chemistry of drainage from waste-rock piles at mine sites is difficult to predict because of a number of uncertainties including heterogeneous reactive mineral content, distribution of minerals, weathering rates and physical flow properties. In this presentation, we examine the effects of mixing on drainage chemistry over timescales of 100s of years. We use a 1-D streamtube conceptualization of flow in waste rocks and multicomponent reactive transport modeling. We simplify the reactive system to consist of acid-producing sulfide minerals and acid-neutralizing carbonate minerals and secondary sulfate and iron oxide minerals. We create multiple realizations of waste-rock piles with distinct distributions of reactive minerals along each flow path and examine the uncertainty of drainage geochemistry through time. The limited mixing of streamtubes that is characteristic of the vertical unsaturated flow in many waste-rock piles, allows individual flowpaths to sustain acid or neutral conditions to the base of the pile, where the streamtubes mix. Consequently, mixing and the acidity/alkalinity balance of the streamtube waters, and not the overall acid- and base-producing mineral contents, control the instantaneous discharge chemistry. Our results show that the limited mixing implied by preferential flow and the heterogeneous distribution of mineral contents lead to large uncertainty in drainage chemistry over short and medium time scales. However, over longer timescales when one of either the acid-producing or neutralizing primary phases is depleted, the drainage chemistry becomes less controlled by mixing and in turn less uncertain. A correct understanding of the temporal variability of uncertainty is key to make informed long-term decisions in mining settings regarding the management of waste material.

  16. Leaching of pyrite by acidophilic heterotrophic iron-oxidizing bacteria in pure and mixed cultures

    Energy Technology Data Exchange (ETDEWEB)

    Bacelar-Nicolau, P.; Johnson, D.B. [Univ. of Wales, Bangor (United Kingdom). School of Biological Sciences

    1999-02-01

    Seven strains of heterotrophic iron-oxidizing acidophilic bacteria were examined to determine their abilities to promote oxidative dissolution of pyrite (FeS{sub 2}) when they were grown in pure cultures and in mixed cultures with sulfur-oxidizing Thiobacillus spp. Only one of the isolates (strain T-24) oxidized pyrite when it was grown in pyrite-basal salts medium. However, when pyrite-containing cultures were supplemented with 0.02% (wt/vol) yeast extract, most of the isolates oxidized pyrite, and one (strain T-24) promoted rates of mineral dissolution similar to the rates observed with the iron-oxidizing autotroph Thiobacillus ferroxidans. Pyrite oxidation by another isolate (strain T-21) occurred in cultures containing between 0.005 and 0.05% (wt/vol) yeast extract but was completely inhibited in cultures containing 0.5% yeast extract. Ferrous iron was also needed for mineral dissolution by the iron-oxidizing heterotrophs, indicating that these organisms oxidize pyrite via the indirect mechanism. Mixed cultures of three isolates (strains T-21, T-232, and T-24) and the sulfur-oxidizing autotroph Thiobacillus thiooxidans promoted pyrite dissolution; since neither strains T-21 and T-23 nor T. thiooxidans could oxidize this mineral in yeast extract-free media, this was a novel example of bacterial synergism. Mixed cultures of strains T-21 and T-23 and the sulfur-oxidizing mixotroph Thiobacillus acidophilus also oxidized pyrite but to a lesser extent than did mixed cultures containing T. thiooxidans. Pyrite leaching by strain T -23 grown in an organic compound-rich medium and incubated either shaken or unshaken was also assessed. The potential environmental significance of iron-oxidizing heterotrophs in accelerating pyrite oxidation is discussed.

  17. Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kraleva, E., E-mail: ekraleva@gmail.com [Institute of Biodiversity and Ecosystems Research, Bulgarian Academy of Sciences, Sofia, Gagarin st.2 (Bulgaria); Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Saladino, M.L. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Caponetti, E. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Nasillo, G. [Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Jiratova, K. [Institute of Chemical Process Fundamentals, 16502 Prague 6 (Czech Republic)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Preparation of ternary mixed oxide by sol-gel method. Black-Right-Pointing-Pointer Catalytic properties of the three-mixed oxides. Black-Right-Pointing-Pointer Heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} and its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40} that of active components in catalytic systems for thiophene hydrodesulfurization (HDS). - Abstract: TiAlZr mixed oxides, synthesized using sol-gel method, were characterized and used as supports of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} or its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40}. Structure, morphology and textural properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in thiophene hydrodesulfurization (HDS). No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of the support composition.

  18. Ethanol steam reforming over Mg-Al mixed-oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, L.J.; Hudgins, R.R.; Silveston, P.L.; Croiset, E. [Waterloo Univ., ON (Canada). Dept. of Chemical Engineering

    2007-07-01

    Eight magnesium-aluminium (Mg-Al) mixed oxides and magnesium oxide (MgO) and aluminium oxide (Al{sub 2}O{sub 3}) were studied in order to identify the most effective Mg-Al mixed oxide for hydrogen production via ethanol steam reforming. Co-precipitated precursors were calcinated to prepare the Mg-Al mixed oxides. Activity and selectivity of the mixed oxides for ethanol steam reforming were evaluated at 773 and 923 K. Results showed that all catalysts performed poorly during the steam reforming reaction, and produced low rates of hydrogen, carbon monoxide (CO) and carbon dioxide (CO{sub 2}). Catalysts with an MgAl{sub 2}O{sub 4} spinel crystal structure gave the best performance at both reaction temperatures. However, carbon deposits were discovered on all catalysts for reactions performed at 923 K. Co-precipitation resulted in more effective contact between the Mg and Al in the form of Mg-Al LDO and MgAL{sub 2}O{sub 3}. The absence of pure oxides suggested that Mg and Al were chemically coupled in the mixed oxide catalysts. Results of the study showed that the catalyst with an atomic ratio of 0.66 Mg1Al2 was the most active and achieved the highest rates of production for hydrogen. 14 refs., 3 tabs., 1 fig.

  19. Study on Catalysts with Rhodium Loading on Different Cerium-Zirconium Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalysts with Rh loading on different cerium-zirconium mixed oxides were characterized by BET, H2-TPR and OSC. The effects of different cerium-zirconium mixed oxides on catalytic performance and thermal stability of Rh loaded catalyst were studied. The results show that: (1) Rh can enhance cerium-zirconium mixed oxides OSC and catalytic reaction rates; (2) cerium-zirconium mixed oxides with high Ce contents and low Zr contents are more favorable to the stability of catalysts. Moreover, the contents of CeO2 have important effect on catalysts characteristics, and the addition of some rare earth components, such as La, Pr and Nd also have some influences.

  20. Microbial Ecology Assessment of Mixed Copper Oxide/Sulfide Dump Leach Operation

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, Debby Fox; Thompson, David Neal; Noah, Karl Scott

    1999-06-01

    Microbial consortia composed of complex mixtures of autotrophic and heterotrophic bacteria are responsible for the dissolution of metals from sulfide minerals. Thus, an efficient copper bioleaching operation depends on the microbial ecology of the system. A microbial ecology study of a mixed oxide/sulfide copper leaching operation was conducted using an "overlay" plating technique to differentiate and identify various bacterial consortium members of the genera Thiobacillus, “Leptospirillum”, “Ferromicrobium”, and Acidiphilium. Two temperatures (30°C and 45°C) were used to select for mesophilic and moderately thermophilic bacteria. Cell numbers varied from 0-106 cells/g dry ore, depending on the sample location and depth. After acid curing for oxide leaching, no viable bacteria were recovered, although inoculation of cells from raffinate re-established a microbial population after three months. Due to low the pH of the operation, very few non-iron-oxidizing acidophilic heterotrophs were recovered. Moderate thermophiles were isolated from the ore samples. Pregnant liquor solutions (PLS) and raffinate both contained a diversity of bacteria. In addition, an intermittently applied waste stream that contained high levels of arsenic and fluoride was tested for toxicity. Twenty vol% waste stream in PLS killed 100% of the cells in 48 hours, indicating substantial toxicity and/or growth inhibition. The data indicate that bacteria populations can recover after acid curing, and that application of the waste stream to the dump should be avoided. Monitoring the microbial ecology of the leaching operation provided significant information that improved copper recovery.

  1. Selenium dioxide catalysed oxidation of acetic acid hydrazide by bromate in aqueous hydrochloric acid medium

    Indian Academy of Sciences (India)

    R S Yalgudre; G S Gokavi

    2012-07-01

    Selenium dioxide catalysed acetic acid hydrazide oxidation by bromate was studied in hydrochloric acid medium. The order in oxidant concentration, substrate and catalyst were found to be unity. Increasing hydrogen ion concentration increases the rate of the reaction due to protonation equilibria of the oxidant. The mechanism of the reaction involves prior complex formation between the catalyst and substrate, hydrazide, followed by its oxidation by diprotonated bromate in a slow step. Acetic acid was found to be the oxidation product. Other kinetic data like effect of solvent polarity and ionic strength on the reaction support the proposed mechanism.

  2. Oxidative stress and nucleic acid oxidation in patients with chronic kidney disease.

    Science.gov (United States)

    Sung, Chih-Chien; Hsu, Yu-Chuan; Chen, Chun-Chi; Lin, Yuh-Feng; Wu, Chia-Chao

    2013-01-01

    Patients with chronic kidney disease (CKD) have high cardiovascular mortality and morbidity and a high risk for developing malignancy. Excessive oxidative stress is thought to play a major role in elevating these risks by increasing oxidative nucleic acid damage. Oxidative stress results from an imbalance between reactive oxygen/nitrogen species (RONS) production and antioxidant defense mechanisms and can cause vascular and tissue injuries as well as nucleic acid damage in CKD patients. The increased production of RONS, impaired nonenzymatic or enzymatic antioxidant defense mechanisms, and other risk factors including gene polymorphisms, uremic toxins (indoxyl sulfate), deficiency of arylesterase/paraoxonase, hyperhomocysteinemia, dialysis-associated membrane bioincompatibility, and endotoxin in patients with CKD can inhibit normal cell function by damaging cell lipids, arachidonic acid derivatives, carbohydrates, proteins, amino acids, and nucleic acids. Several clinical biomarkers and techniques have been used to detect the antioxidant status and oxidative stress/oxidative nucleic acid damage associated with long-term complications such as inflammation, atherosclerosis, amyloidosis, and malignancy in CKD patients. Antioxidant therapies have been studied to reduce the oxidative stress and nucleic acid oxidation in patients with CKD, including alpha-tocopherol, N-acetylcysteine, ascorbic acid, glutathione, folic acid, bardoxolone methyl, angiotensin-converting enzyme inhibitor, and providing better dialysis strategies. This paper provides an overview of radical production, antioxidant defence, pathogenesis and biomarkers of oxidative stress in patients with CKD, and possible antioxidant therapies.

  3. Oxidative Stress and Nucleic Acid Oxidation in Patients with Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Chih-Chien Sung

    2013-01-01

    Full Text Available Patients with chronic kidney disease (CKD have high cardiovascular mortality and morbidity and a high risk for developing malignancy. Excessive oxidative stress is thought to play a major role in elevating these risks by increasing oxidative nucleic acid damage. Oxidative stress results from an imbalance between reactive oxygen/nitrogen species (RONS production and antioxidant defense mechanisms and can cause vascular and tissue injuries as well as nucleic acid damage in CKD patients. The increased production of RONS, impaired nonenzymatic or enzymatic antioxidant defense mechanisms, and other risk factors including gene polymorphisms, uremic toxins (indoxyl sulfate, deficiency of arylesterase/paraoxonase, hyperhomocysteinemia, dialysis-associated membrane bioincompatibility, and endotoxin in patients with CKD can inhibit normal cell function by damaging cell lipids, arachidonic acid derivatives, carbohydrates, proteins, amino acids, and nucleic acids. Several clinical biomarkers and techniques have been used to detect the antioxidant status and oxidative stress/oxidative nucleic acid damage associated with long-term complications such as inflammation, atherosclerosis, amyloidosis, and malignancy in CKD patients. Antioxidant therapies have been studied to reduce the oxidative stress and nucleic acid oxidation in patients with CKD, including alpha-tocopherol, N-acetylcysteine, ascorbic acid, glutathione, folic acid, bardoxolone methyl, angiotensin-converting enzyme inhibitor, and providing better dialysis strategies. This paper provides an overview of radical production, antioxidant defence, pathogenesis and biomarkers of oxidative stress in patients with CKD, and possible antioxidant therapies.

  4. Flotation of cobalt bearing minerals from a mixed copper-cobalt oxidized ore

    OpenAIRE

    2012-01-01

    M.Tech. (Extraction Metallurgy) The techniques for the flotation of mixed copper and cobalt bearing oxide ores using the sulphidization method in order to recover the oxidized copper and cobalt bearing minerals have been well documented by previous researchers. These processes have been successfully implemented in many of the metallurgical plant operations in the Democratic Republic of Congo (DRC). The mixed copper and cobalt oxidised ores from this region present significant chal-lenges t...

  5. Study on Mg/Fe Mixed Oxides Derived from Hydrotalite as De—SOx Catalyst

    Institute of Scientific and Technical Information of China (English)

    GuangLanZHUO; YinFeiCHEN; 等

    2002-01-01

    A novel class of desulfurization agent derived from hydrotalcite has been developed and its activity for SOx uptake have been investigated. The results showed that the Mg/Fe mixed oxide having high SOx uptake ability at a broad reaction temperature (e.g.673K-973K). The Mg/Fe ratio of the mixed oxide strongly affect the desulfurization role of the material and it can be used repeatly without much loss of SOx uptake ability.

  6. Study on Mg/Fe Mixed Oxides Derived from Hydrotalcite as De-SOx Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel class of desulfurization agent derived from hydrotalcite has been developed and its activity for Sox uptake have been investigated. The results showed that the Mg/Fe mixed oxide having high Sox uptake ability at a broad reaction temperature (e.g. 673K ~ 973K). The Mg/Fe ratio of the mixed oxide strongly affect the desulfurization role of the material and it can be used repeatly without much loss of Sox uptake ability.

  7. Wet oxidation kinetics of refractory low molecular mass carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Levec, J.

    1999-10-01

    Wet oxidation kinetics of aqueous solutions of formic, acetic, oxalic, and glyoxalic acids was studied in a titanium autoclave at a temperature range of 150--320 C and oxygen partial pressures between 8 and 60 bar. Oxidation reactions obeyed a first-order kinetics with respect to concentration of all substrates. On the basis of acid concentration decay, the activation energy for acetic, oxalic, and glyoxalic acid oxidation was 178, 137, and 97 kJ/mol, respectively; whereas on the total organic carbon (TOC) conversion basis, these values were slightly higher, namely 182, 141, and 104 kJ/mol. The activation energy for formic acid took a unique value of 149 kJ/mol regardless of the type of concentration used. The rate of oxidation was proportional to a square root of oxygen concentration (partial pressure) for acetic, formic, and oxalic acids, whereas it was linearly proportional for glyoxalic acid. When sufficiently high oxygen partial pressure was applied ({ge}22 bar), the individual acid conversion in a mixture of these acids was well predicted by the rate expression derived for that acid. The lumped TOC concentration of mixtures did not obey a first-order kinetic behavior, although underlying TOC kinetics for each individual acid was linear. The oxidation results are also discussed in a view of speculated reaction pathways and the reactor material.

  8. Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Clapsaddle, B; Gash, A; Plantier, K; Pantoya, M; Jr., J S; Simpson, R

    2004-04-27

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. By introducing a fuel metal, such as aluminum, into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. In addition, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. These organic additives can cause the generation of gas upon ignition of the materials, therefore resulting in a composite material that can perform pressure/volume work. Furthermore, the desired organic functionality is well dispersed throughout the composite material on the nanoscale with the other components, and is therefore subject to the same increased reaction kinetics. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of iron(III) oxide/organosilicon oxide nanocomposites and their performance as energetic materials will be discussed.

  9. Acetic Acid bacteria: physiology and carbon sources oxidation.

    Science.gov (United States)

    Mamlouk, Dhouha; Gullo, Maria

    2013-12-01

    Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called "oxidative fermentations", especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism.

  10. Conversion of Russian weapon-grade plutonium into oxide for mixed oxide (MOX) fuel fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Glagovski, E.; Zakharkin, B. [A.A. Bochvar All-Russian Research Institute of Inorganic Materials, Russian Research Center, Moscow (Russian Federation); Kolotilov, Y. [Specialized State Design Institute, GSPI, Moscow (Russian Federation); Glagolenko, Y.; Skobtsov, A. [Mayak Production Association, Ozyorsk (Russian Federation); Zygmunt, S.; Mason, C.; Hahn, W.; Durrer, R. [Los Alamos National Lab., Nuclear Materials and Technology Div. NMT, Los Alamos, N.M. (United States); Thomas, S. [National Nuclear Security Administration, Washington DC (United States); Sicard, B.; Brossard, P.; Herlet, N. [CEA Marcoule 30 (France); Fraize, G.; Villa, A. [Cogema, 78 - Saint Quentin en Yvelines (France)

    2001-07-01

    Progress has been made in the Russian Federation towards the conversion of Russian weapons-grade plutonium (W-Pu) into plutonium oxide (PuO{sub 2}) suitable for further manufacture into mixed oxide (MOX) fuels. This program is funded both by French Commissariat at the Atomic Energy (CEA) and the US National Nuclear Security Administration (NNSA). The French program was started in the frame of the two cooperation agreements signed between Russian Federation and France in November 1992 concerning dismantling of nuclear weapons and the use of their nuclear materials for civilian purposes. The US program was started in 1998 in response to US proliferation concerns and the acknowledged international need to decrease available W-Pu. Russia has selected both the conversion process and the manufacturing site. This paper discusses the present state of development towards fulfilling this mission: the demonstration plant designed to process small amounts of Pu and validate all process stages and the industrial plant that will process up to 5 metric tons of Pu per year. (author)

  11. Titanium oxide modification with oxides of mixed cobalt valence for photo catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Alanis O, R.; Jimenez B, J., E-mail: jaime.jimenez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    In the present work, heterogenous photo catalysis, a technique often used for organic compound degradation toxic in water, was used. The photo catalyst most often used in this technique is TiO{sub 2}, which due to its physical and chemical properties, can degrade a great number of organic compounds. In addition, in recent years it has been verified that the doping of semiconductors with metals or metallic oxides increases the photo catalytic activity of these semiconductors, which is why it was proposed for doping by the impregnating method using commercial TiO{sub 2} synthesized by the Degussa company (TiO{sub 2} Degussa P25) with and oxide of mixed cobalt valence (Co{sub 3}O{sub 4}) synthesized using the sol-gel method. The synthesized photo catalyst TiO{sub 2}/Co{sub 3}O{sub 4} was characterized by the techniques of X-ray diffraction, scanning electronic microscopy, Raman spectroscopy and finally, photo catalytic tests by means of the degradation of methylene blue. (Author)

  12. Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes

    Science.gov (United States)

    Sigmann, Samuella B.; Wheeler, Dale E.

    2004-01-01

    A procedure by which the reactions are used to quantitatively determine the amount of total acid, the amount of total ascorbic acid and the amount of citric acid in a given sample of powdered drink mix, are described. A safe, reliable and low-cost quantitative method to analyze consumer product for acid content is provided.

  13. Enthalpy of mixing of methacrylic acid with organic solvents at 293 K

    Science.gov (United States)

    Sergeev, V. V.

    2016-03-01

    The enthalpies of mixing of binary systems of methacrylic acid with acetonitrile, benzene, hexane, 1,2-dichloroethane, and acetic acid are measured calorimetrically at 293 K and atmospheric pressure. The enthalpy of mixing of all the studied binary systems is positive over the range of concentrations.

  14. Electrochemical oxidation of reverse osmosis concentrate on mixed metal oxide (MMO) titanium coated electrodes.

    Science.gov (United States)

    Bagastyo, Arseto Y; Radjenovic, Jelena; Mu, Yang; Rozendal, René A; Batstone, Damien J; Rabaey, Korneel

    2011-10-15

    Reverse osmosis (RO) membranes have been successfully applied around the world for wastewater reuse applications. However, RO is a physical separation process, and besides the clean water stream (permeate) a reverse osmosis concentrate (ROC) is produced, usually representing 15-25% of the feed water flow and containing the organic and inorganic contaminants at higher concentrations. In this study, electrochemical oxidation was investigated for the treatment of ROC generated during the reclamation of municipal wastewater effluent. Using laboratory-scale two-compartment electrochemical systems, five electrode materials (i.e. titanium coated with IrO2-Ta2O5, RuO2-IrO2, Pt-IrO2, PbO2, and SnO2-Sb) were tested as anodes in batch mode experiments, using ROC from an advanced water treatment plant. The best oxidation performance was observed for Ti/Pt-IrO2 anodes, followed by the Ti/SnO2-Sb and Ti/PbO2 anodes. The effectiveness of the treatment appears to correlate with the formation of oxidants such as active chlorine (i.e. Cl2/HClO/ClO-). As a result, electro-generated chlorine led to the abundant formation of harmful by-products such as trihalomethanes (THMs) and haloacetic acids (HAAs), particularly at Ti/SnO2-Sb and Ti/Pt-IrO2 anodes. The highest concentration of total HAAs (i.e. 2.7 mg L(-1)) was measured for the Ti/SnO2-Sb electrode, after 0.55 Ah L(-1) of supplied specific electrical charge. Irrespective of the used material, electrochemical oxidation of ROC needs to be complemented by a polishing treatment to alleviate the release of halogenated by-products. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Authigenic iron oxide formation in the estuarine mixing zone of the Yangtze River

    Science.gov (United States)

    Fan, D. J.; Neuser, R. D.; Sun, X. G.; Yang, Z. S.; Guo, Z. G.; Zhai, S. K.

    2008-02-01

    Estuaries are elementary geochemical fronts where river water and seawater mix. Within this mixing zone, iron and other non-conservative elements can undergo complex reactions to form new solid phases. In order to understand authigenic iron oxide formation in the Yangtze River Estuary, two onsite water-mixing sets of experiments were conducted, one by mixing variable amounts of unfiltered Yangtze River water with filtered East China Sea water of different salinity (set 1), the other by mixing variable amounts of filtered Yangtze River water with filtered East China Sea water of different salinity (set 2). In set 2, the minerals newly formed in the course of mixing were investigated by means of a scanning electron microscope fitted with an energy-dispersive X-ray analytical system. It was found that ferrihydrite and lepidocrocite were formed in these mixing experiments, coexisting in nearly equal amounts. These iron oxides appear as aggregated particles with a large grain-size range of several microns to more than 100 μm. The electrolytic properties of seawater played an important role in the formation of these authigenic iron oxides. Kaolinite and organic aggregates were also found in the experimentally mixed pre-filtered waters. Amounts of newly formed suspended matter (set 2) were one to three orders of magnitude lower than those of total suspended matter (TSM) (set 1). This implies that newly formed minerals represent only a very small proportion of TSM in the estuarine mixing zone of the Yangtze River.

  16. Polyaniline: Aniline oxidation with strong and weak oxidants under various acidity

    Energy Technology Data Exchange (ETDEWEB)

    Bláha, Michal, E-mail: blaha@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic); Trchová, Miroslava; Bober, Patrycja; Morávková, Zuzana [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic); Prokeš, Jan [Charles University, Faculty of Mathematics and Physics, 180 00 Prague 8 (Czech Republic); Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic)

    2017-06-15

    Aniline was oxidized with three strong inorganic oxidants (ammonium peroxydisulfate, cerium(IV) sulfate, potassium dichromate), two weak inorganic oxidants (iron(III) chloride, silver nitrate), and one organic oxidant (p-benzoquinone) in aqueous solutions of methanesulfonic acid (MSA) of various concentration. Whereas oxidation of aniline with ammonium peroxydisulfate yielded high-molecular-weight conducting polyaniline (PANI) in the whole acidity range, the oxidation with cerium(IV) sulfate led also to a single product close to PANI with considerably lower molecular weight and lower conductivity. Potassium dichromate gave PANI only at high concentration of MSA. The use of iron(III) chloride yielded composite mixtures of PANI and low-molecular-weight aniline oligomers. The oxidation of aniline with silver nitrate led to composites of silver and an organic part, which was constituted either by aniline oligomers or conducting polyaniline or both. p-Benzoquinone as oxidant produced mainly aniline oligomers with poor conductivity and 2,5-dianilino-p-benzoquinone-like structure detected in FTIR and Raman spectra when oxidation proceeded with weak oxidants. A general model of oxidation with strong and weak oxidants was formulated. - Highlights: • Comparison of aniline oxidation with oxidants of different redox potential. • UV–vis, FTIR and Raman spectroscopies combined with size-exclusion chromatography. • The contents of polymer and oligomers were analyzed and discussed. • General model of aniline oxidation with strong and weak oxidants was formulated.

  17. Acid leaching of oxide-sulphide copper ore prior the flotation: A way for an increased metal recovery

    Directory of Open Access Journals (Sweden)

    Sokić Miroslav D.

    2015-01-01

    Full Text Available Copper mine "Cerovo"- East Serbia as well as the other ore bodies in its vicinity contain a significant amount of oxide copper minerals in their uper layers (>40%. Processing of such mixed ores by the existing concentration technologies leads to a substantial copper losses (<60%. Reduction of "oxide copper", by acid leaching prior the flotation concentration, can increase the overall copper efficiency up to more than 70% in the single-stage leaching, achieving an efficiency in the flotation concentration stage higher than 75%. Based on the performed experimental results the flow sheet for processing of the mixed oxide-sulphide copper ore is proposed.

  18. Degradation of organophosphorus pesticide parathion methyl on nanostructured titania-iron mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Henych, Jiří, E-mail: henych@iic.cas.cz [Department of Material Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 25068 Řež (Czech Republic); Štengl, Václav; Slušná, Michaela; Matys Grygar, Tomáš [Department of Material Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 25068 Řež (Czech Republic); Janoš, Pavel; Kuráň, Pavel; Štastný, Martin [Faculty of the Environment, J.E. Purkyně University, Králova Výšina 7, 400 96 Ústí nad Labem (Czech Republic)

    2015-07-30

    Highlights: • Ti–Fe mixed oxides were synthesized via low-temperature one-pot method. • Mixed oxides were used for degradation of parathion methyl. • Pure reference oxide samples showed no degradation ability. • Mixed oxides reached 70% degree of conversion of parathion methyl. - Abstract: Titania-iron mixed oxides with various Ti:Fe ratio were prepared by homogeneous hydrolysis of aqueous solutions of titanium(IV) oxysulphate and iron(III) sulphate with urea as a precipitating agent. The synthesized samples were characterized by X-ray diffraction, Raman and infrared spectroscopy, scanning and transmission electron microscopy, XRF analysis, specific surface area (BET) and porosity determination (BJH). These oxides were used for degradation of organophosporus pesticide parathion methyl. The highest degradation efficiency approaching <70% was found for the samples with Ti:Fe ratio 0.25:1 and 1:0.25. Contrary, parathion methyl was not degraded on the surfaces of pure oxides. In general, the highest degradation rate exhibited samples consisted of the iron or titanium oxide containing a moderate amount of the admixture. However, distinct correlations between the degradation rate and the sorbent composition were not identified.

  19. Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Lidong, Wang, E-mail: wld@tsinghua.edu.cn [School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003 (China); Department of Environmental Science and Engineering, Tsinghua University, Beijing 100054 (China); Yongliang, Ma, E-mail: liang@tsinghua.edu.cn [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100054 (China); Wendi, Zhang; Qiangwei, Li; Yi, Zhao [School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003 (China); Zhanchao, Zhang [Jinan Environmental Monitoring Center, Jinan 250014 (China)

    2013-08-15

    Graphical abstract: Ascorbic acid is used as an inhibitor to retard the oxidation rate of magnesium sulfite. It shows that the oxidation rate would decrease greatly with the rise of initial ascorbic acid concentration, which provides a useful reference for sulfite recovery in magnesia desulfurization. -- Highlights: • We studied the kinetics of magnesium sulfite oxidation inhibited by ascorbic acid. • The oxidation process was simulated by a three-phase model and proved by HPLC–MS. • We calculated the kinetic parameters of intrinsic oxidation of magnesium sulfite. -- Abstract: Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is −0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol{sup −1}. Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization.

  20. Mg-Fe-mixed oxides derived from layered double hydroxides: A study of the surface properties

    Directory of Open Access Journals (Sweden)

    Marinković-Nedučin Radmila P.

    2011-01-01

    Full Text Available The influence of surface properties on the selectivity of the synthesized catalysts was studied, considering that their selectivity towards particular hydrocarbons is crucial for their overall activity in the chosen Fischer- -Tropsch reaction. Magnesium- and iron-containing layered double hydroxides (LDH, with the general formula: [Mg1-xFex(OH2](CO3x/2?mH2O, x = = n(Fe/(n(Mg+n(Fe, synthesized with different Mg/Fe ratio and their thermally derived mixed oxides were investigated. Magnesium was chosen because of its basic properties, whereas iron was selected due to its well-known high Fischer-Tropsch activity, redox properties and the ability to form specific active sites in the layered LDH structure required for catalytic application. The thermally less stable multiphase system (synthesized outside the optimal single LDH phase range with additional Fe-phase, having a lower content of surface acid and base active sites, a lower surface area and smaller fraction of smaller mesopores, showed higher selectivity in the Fischer-Tropsch reaction. The results of this study imply that the metastability of derived multiphase oxides structure has a greater influence on the formation of specific catalyst surface sites than other investigated surface properties.

  1. Catalytic propane dehydrogenation over In₂O₃–Ga₂O₃ mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Shuai; Gil, Laura Briones; Subramanian, Nachal; Sholl, David S.; Nair, Sankar; Jones, Christopher W.; Moore, Jason S.; Liu, Yujun; Dixit, Ravindra S.; Pendergast, John G. (Dow); (GIT)

    2015-08-26

    We have investigated the catalytic performance of novel In₂O₃–Ga₂O₃ mixed oxides synthesized by the alcoholic-coprecipitation method for propane dehydrogenation (PDH). Reactivity measurements reveal that the activities of In₂O₃–Ga₂O₃ catalysts are 1–3-fold (on an active metal basis) and 12–28-fold (on a surface area basis) higher than an In₂O₃–Al₂O₃ catalyst in terms of C₃H₈ conversion. The structure, composition, and surface properties of the In₂O₃–Ga₂O₃ catalysts are thoroughly characterized. NH₃-TPD shows that the binary oxide system generates more acid sites than the corresponding single-component catalysts. Raman spectroscopy suggests that catalysts that produce coke of a more graphitic nature suppress cracking reactions, leading to higher C₃H₆ selectivity. Lower reaction temperature also leads to higher C₃H₆ selectivity by slowing down the rate of side reactions. XRD, XPS, and XANES measurements, strongly suggest that metallic indium and In₂O₃ clusters are formed on the catalyst surface during the reaction. The agglomeration of In₂O₃ domains and formation of a metallic indium phase are found to be irreversible under O₂ or H₂ treatment conditions used here, and may be responsible for loss of activity with increasing time on stream.

  2. Carboxylic acid production from brewer's spent grain via mixed culture fermentation.

    Science.gov (United States)

    Liang, Shaobo; Wan, Caixia

    2015-04-01

    This study aimed at investigating carboxylic acid production from brewer's spent grain (BSG) via mixed culture fermentation. The results showed that the distribution of fermentation products was significantly affected by pH conditions and the addition of electron donors. Lactic acid was the dominant component under acidic and alkaline conditions while volatile fatty acids (VFAs) became dominant under the neutral condition. Furthermore, the neutral condition favored the chain elongation of carboxylic acids, especially with ethanol as the electron donor. Ethanol addition enhanced valeric acid and caproic acid production by 44% and 167%, respectively. Lactic acid addition also had positive effects on VFAs production under the neutral condition but limited to C2-C4 products. As a result, propionic acid and butyric acid production was increased by 109% and 152%, respectively. These findings provide substantial evidence for regulating carboxylic acid production during mixed culture fermentation of BSG by controlling pH and adding electron donors.

  3. Targets for modulation of fatty acid oxidation in the heart.

    Science.gov (United States)

    Lopaschuk, Gary D

    2004-03-01

    Fatty acids are a major source of fuel used by the heart to provide large amounts of energy necessary to sustain contractile function. In the healthy heart, a balance between fatty acid and carbohydrate use ensures that energy supply to the heart matches demand. However, myocardial ischemia causes profound changes in metabolism, including alterations in glucose and fatty acid metabolism that can lead to excessive myocardial fatty acid oxidation, which occurs at the expense of glucose oxidation. This contributes to cellular acidosis, a decrease in cardiac efficiency and contractile dysfunction in the ischemic heart. Inhibition of fatty acid oxidation has recently emerged as a promising approach to the prevention of these adverse effects of fatty acids. As a result, a number of key enzymes involved in the metabolism of fatty acids are potential targets for therapeutic intervention in myocardial ischemia. This includes inhibition of fatty acid uptake into the myocyte, inhibition of mitochondrial fatty acid uptake and direct inhibition of fatty acid beta-oxidation. This review describes these potential targets for modulation of energy metabolism in the heart.

  4. Control of differential strain during heating and cooling of mixed conducting metal oxide membranes

    Science.gov (United States)

    Carolan, Michael Francis

    2007-12-25

    Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side and a permeate side, which method comprises controlling the differential strain between the oxidant feed side and the permeate side by varying either or both of the oxygen partial pressure and the total gas pressure on either or both of the oxidant feed side and the permeate side of the membrane while changing the temperature of the membrane from a first temperature to a second temperature.

  5. Formic acid oxidation at platinum-bismuth catalysts

    National Research Council Canada - National Science Library

    Popović Ksenija Đ; Lović Jelena D

    2015-01-01

    ..., activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance...

  6. Sodium Picosulfate, Magnesium Oxide, and Anhydrous Citric Acid

    Science.gov (United States)

    Sodium picosulfate, magnesium oxide, and anhydrous citric acid combination powder is used to empty the colon (large ... clear view of the walls of the colon. Sodium picosulfate is in a class of medications called ...

  7. AMPK-independent pathways regulate skeletal muscle fatty acid oxidation

    DEFF Research Database (Denmark)

    Dzamko, Nicolas; Schertzer, Jonathan D.; Ryall, James G.

    2008-01-01

    , malonyl-CoA levels were reduced and rates of fatty acid oxidation were comparable between genotypes. During treadmill exercise both KD and WT mice had similar values of respiratory exchange ratio. These studies suggested the presence of an alternative ACC2 kinase(s). Using a phosphoproteomics......The activation of AMP-activated protein kinase (AMPK) and phosphorylation/inhibition of acetyl-CoA carboxylase 2 (ACC2) is believed to be the principal pathway regulating fatty acid oxidation. However, during exercise AMPK activity and ACC Ser-221 phosphorylation does not always correlate...... with rates of fatty acid oxidation. To address this issue we have investigated the requirement for skeletal muscle AMPK in controlling aminoimidazole-4-carboxymide-1-beta-d-ribofuranoside (AICAR) and contraction-stimulated fatty acid oxidation utilizing transgenic mice expressing a muscle-specific kinase...

  8. Efficient powder blending in support of plutonium conversion for mixed oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Dennison, D.K.; Brucker, J.P.; Martinez, H.E.

    1999-06-07

    This paper describes a unique system that is used to mix and blend multiple batches of plutonium oxide powder of various consistencies into an equivalent number of identical and homogeneously mixed batches. This system is being designed and built to support the Advanced Recovery and Integrated Extraction System (ARIES) at the Los Alamos TA-55 Plutonium Facility. The ARIES program demonstrates dismantlement of nuclear pits, retrieval of the plutonium components, and conversion of the plutonium into an oxide for eventual use in mixed oxide (MOX) fuel for nuclear reactors. The purpose of this powder blending work is to assure that ARIES oxide is converted into an unclassified homogeneous mixture and that consistent feed material is available for MOX fuel assembly. This blending system is being assembled in a selected glovebox a TA-55 using an LANL designed split/combine apparatus, a commercial Turbula blending unit, and several additional supporting hardware components.

  9. Mixed conductivity in terbia-stabilized bismuth oxide

    NARCIS (Netherlands)

    Vinke, I.C.; Boukamp, B.A.; Vries, de K.J.; Burggraaf, A.J.

    1992-01-01

    The mixed conducting solid solution 0.75Bi2O3−0.25Tb4O7 (BT40) was studied by impedance techniques using ionically blocking electrodes. These measurements confirmed the p-type electronic conductivity suggested in literature. In air at temperatures between 600 and 900 K the ionic transference number

  10. Bioleaching of metal from municipal waste incineration fly ash using a mixed culture of sulfur-oxidizing and iron-oxidizing bacteria.

    Science.gov (United States)

    Ishigaki, Tomonori; Nakanishi, Akane; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori

    2005-08-01

    We investigated the behavior and characteristics of metal leaching from municipal solid waste incineration (MSWI) fly ash among pure cultures of a sulfur-oxidizing bacterium (SOB) and an iron-oxidizing bacterium (IOB) and a mixed culture. The IOB has a high metal-leaching ability, though its tolerability against the ash addition is low. The SOB might better tolerate an increase in ash addition than the IOB, though metal leaching ability of the SOB is limited. Mixed culture could compensate for these deficiencies, and high metal leachability was exhibited in the 1% ash culture, i.e., 67% and 78% of leachabilities for Cu and Zn, respectively, and 100% for Cr and Cd. Furthermore, comparably high leachabilities such as 42% and 78% for Cu and Zn were observed even in the 3% ash cultures. Characterization of metal leaching by the mixed culture revealed that the acidic and oxidizing condition had remained stable thorough the experimental period. Ferric iron remained in the mixed culture, and the metal leaching was enhanced by redox mechanisms coupling with the leaching by sulfate. An increase of ferrous iron enhanced the Cr, Cu, and As leaching. The optimum concentration of sulfur existed for As and Cr (5 gl(-1)) and Cu (2 gl(-1)). The presence of the degradable and non-degradable organic compound that must be existed in the natural environment or waste landfills made no significant change in the leachability of metals other than Zn. These results suggested that bioleaching using a mixed culture of SOB and IOB is a promising technology for recovering the valuable metals from MSWI fly ash.

  11. Studies on carboxylated graphene oxide incorporated polyetherimide mixed matrix ultrafiltration membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kaleekkal, Noel Jacob, E-mail: noeljacob89@gmail.com [Membrane Laboratory, Department of Chemical Engineering, ACT, Anna University, Chennai, 600025 (India); Thanigaivelan, A., E-mail: thanichemstar@gmail.com [Membrane Laboratory, Department of Chemical Engineering, ACT, Anna University, Chennai, 600025 (India); Rana, Dipak, E-mail: rana@uottawa.ca [Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur Private, Ottawa, Ontario, K1N 6N5 (Canada); Mohan, D., E-mail: mohantarun@gmail.com [Membrane Laboratory, Department of Chemical Engineering, ACT, Anna University, Chennai, 600025 (India)

    2017-01-15

    In this work the graphene oxide prepared by the modified Hummers’ method was effectively carboxylated. These carboxylated graphene oxide (c-GO) microsheets was characterized by X-ray diffraction analysis, Raman shift, zeta potential, and their morphology was observed using a high resolution scanning/transmission electron microscopy. Polyetherimide mixed matrix membranes (MMMs) were fabricated by the non-solvent induced phase separation technique with varying concentration of this microsheet. The presence of these microsheets on the membrane surface was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy and could also be confirmed visually by optical images. The membranes were further characterized; they showed a greater water flux, higher porosity, and sufficient thermal stability. Incorporation of these microsheets improved the hydrophilicity of the membrane confirmed by the lower contact angle values, which in turn explained the lower interfacial free energy, the increase in work of adhesion, the higher solid-vapor free energy and the spreading coefficient. Membranes loaded with 0.3 wt% of c-GO showed a flux recovery of 94% and only a small flux decline even after 180 min of filtration of humic acid (HA) solution. The efficiency of these membranes in removal of HA, toxic metal ions was also investigated. The bacterial anti-adhesion property of c-GO in the membranes was also explored using Escherichia coli, as a model bio-foulant. The charge of the microsheets and their unique architecture imparts higher hydrophilicity and greater fouling resistance along with improved permeation flux when incorporated into the polymer matrix. - Highlights: • Novel membranes by incorporating carboxylated GO into polyetherimide matrix. • Modified membranes exhibited greater porosity, flux and high humic acid rejection. • Nanoplatelets improved the flux recovery ratio to >94%. • Liquid phase polymer based retention utilized for toxic heavy metal

  12. Induction of omega-oxidation of monocarboxylic acids in rats by acetylsalicylic acid.

    Science.gov (United States)

    Kundu, R K; Tonsgard, J H; Getz, G S

    1991-12-01

    The accumulation of dicarboxylic acids, particularly long chain, is a prominent feature of Reye's syndrome and diseases of peroxisomal metabolism. We assessed the omega-oxidation of a spectrum of fatty acids in rats and asked whether pretreatment of rats with aspirin, which is known to predispose children to Reye's syndrome, would affect omega-oxidation of long chain fatty acids. We found that aspirin increased liver free fatty acids and increased the capacity for omega-oxidation three- to sevenfold. Omega-oxidation of long chain substrate was stimulated to a greater degree than medium chain substrate and was apparent within one day of treatment, at serum aspirin concentrations below the therapeutic range in humans. The apparent Km for lauric acid was 0.9 microM and 12 microM for palmitate. We also found a difference in the storage stability of activity toward medium and long chain substrate. Saturating concentrations of palmitate had no effect on the formation of dodecanedioic acid, whereas laurate decreased but never eliminated the omega-oxidation of palmitate. 97% of the total laurate omega-oxidative activity recovered was found in the microsomes, but 32% of palmitate omega-oxidative activity was present in the cytosol. These results demonstrate that aspirin is a potent stimulator of omega-oxidation and suggest that there may be multiple enzymes for omega-oxidation with overlapping substrate specificity.

  13. Design of amphoteric mixed oxides of zinc and Group 3 elements (Al, Ga, In): migration effects on basic features.

    Science.gov (United States)

    Mekki-Berrada, Adrien; Grondin, Didier; Bennici, Simona; Auroux, Aline

    2012-03-28

    The design of new amphoteric catalysts is of great interest for several industrial processes, especially those covering dehydration and dehydrogenation phenomena. Adsorption microcalorimetry was used to monitor the design of mixed oxides of zinc with Group 3 elements (aluminium, gallium, indium) with amphoteric character and enhanced specific surface area. Acid-base features were found to evolve non-linearly with the relative amounts of metal, and the strengths of the created acidic or basic sites were measured by adsorption microcalorimetry. A panel of bifunctional catalysts of various acid-base (amounts, strengths) and redox character was obtained. Besides, special interest was given to In-Zn mixed oxides for their enhanced basicity: this series of catalysts displays important basic features of high strength (q(diff) (SO₂ ads.) > 200 kJ mol(SO₂)⁻¹ in substantial amounts (1 - 2 μmol m(catalyst)⁻²), whose impact on efficiency or selectivity in catalytic dehydration/dehydrogenation can be valuable.

  14. Morphological characteristics, oxidative stability and enzymic hydrolysis of amylose-fatty acid complexes.

    Science.gov (United States)

    Marinopoulou, Anna; Papastergiadis, Efthimios; Raphaelides, Stylianos N; Kontominas, Michael G

    2016-05-05

    Complexes of amylose with fatty acids varying in carbon chain length and degree of unsaturation were prepared at 30, 50 or 70°C by dissolving amylose in 0.1N KOH and mixing with fatty acid potassium soap solution. The complexes were obtained in solid form as precipitates after neutralization. SEM microscopy revealed that the morphology of the complexes was that of ordered lamellae separated from amorphous regions whereas confocal laser scanning microscopy showed images of the topography of the guest molecules in the complex matrix. FTIR spectroscopy revealed that the absorption peak attributed to carbonyl group of free fatty acid was shifted when the fatty acid was in the form of amylose complex. Thermo-gravimetry showed that the unsaturated fatty acids were effectively protected from oxidation when they were complexed with amylose whereas enzymic hydrolysis experiments showed that the guest molecules were quantitatively released from the amylose complexes.

  15. The Oxidation of Hydrazine by Nitric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Karraker, D.G.

    2001-07-02

    Hydrazine nitrate-nitric acid solutions are used in the ion exchange process for separating Pu-238 and Np-237 and have been found to dissolve plutonium metal in a manner advantageous to SRP metal recovery operations. Laboratory tests on the stability of hydrazine in nitric acid solutions were performed to obtain accurate data, and the results of these tests are reported here. These tests provide sufficient information to specify temperature control for hydrazine-nitric acid solutions in plant processes.

  16. Platinum nanoparticles–manganese oxide nanorods as novel binary catalysts for formic acid oxidation

    Directory of Open Access Journals (Sweden)

    Mohamed S. El-Deab

    2012-01-01

    Full Text Available The current study proposes a novel binary catalyst system (composed of metal/metal oxide nanoparticles as a promising electrocatalyst in formic acid oxidation. The electro-catalytic oxidation of formic acid is carried out with binary catalysts of Pt nanoparticles (nano-Pt and manganese oxide nanorods (nano-MnOx electrodeposited onto glassy carbon (GC electrodes. Cyclic voltammetric (CV measurements showed that unmodified GC and nano-MnOx/GC electrodes have no catalytic activity. While two oxidation peaks were observed at nano-Pt/GC electrode at ca. 0.2 and 0.55 V (corresponding to the direct oxidation of formic acid and the oxidation of the poisoning CO intermediate, respectively. The combined use of nano-MnOx and nano-Pt results in superb enhancement of the direct oxidation pathway. Nano-MnOx is shown to facilitate the oxidation of CO (to CO2 by providing oxygen at low over-potential. This leads to retrieval of Pt active sites necessary for the direct oxidation of formic acid. The higher catalytic activity of nano-MnOx/nano-Pt/GC electrode (with Pt firstly deposited compared to its mirror image electrode (i.e., with MnOx firstly deposited, nano-Pt/nano-MnOx/GC reveals that the order of the electrodeposition is an essential parameter.

  17. Isoniazid cocrystals with anti-oxidant hydroxy benzoic acids

    Science.gov (United States)

    Mashhadi, Syed Muddassir Ali; Yunus, Uzma; Bhatti, Moazzam Hussain; Tahir, Muhammad Nawaz

    2014-11-01

    Isoniazid is the primary constituent of “triple therapy” used to effectively treat tuberculosis. In tuberculosis and other diseases, tissue inflammation and free radical burst from macrophages results in oxidative stress. These free radicals cause pulmonary inflammation if not countered by anti-oxidants. Therefore, in the present study cocrystals of isoniazid with four anti-oxidant hydroxy benzoic acids have been reported. Gallic acid, 2,3-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, and 3-hydroxybenzoic acid resulted in the formation of cocrystals when reacted with isoniazid. Cocrystal structure analysis confirmed the existence of pyridine-carboxylic acid synthon in the cocrystals of isoniazid with Gallic acid, 2,3-dihydroxybenzoic acid and 3-hydroxybenzoic acid. While cocrystal of 3,5-dihydroxybenzoic acid formed the pyridine-hydroxy group synthon. Other synthons of different graph sets are formed between hydrazide group of isoniazid and coformers involving Nsbnd H⋯O and Osbnd H⋯N bonds. All the cocrystals were in 1:1 stoichiometric ratio.

  18. Effect of preparation conditions on selective oxidation of propane to acrylic acid

    Institute of Scientific and Technical Information of China (English)

    YU Zhen-xing; ZHENG Wei; XU Wen-long; ZHANG Yu-hang; FU Hong-ying; ZHANG Ping

    2009-01-01

    The effects of chemical composition and preparation conditions, especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were investigated. Among the catalysts studied, MO_(1.0)V_(0.3)Te_(0.23)Nb_(0.12)O_x catalyst calcined in inert atmosphere at 600 ℃ shows the best performance in terms of propane conversion and selectivity to acrylic acid. The results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure, chemical composition, which are related to their catalytic performances; and 51.0% propane conversion and 30.5% one-pass yield to acrylic acid can be achieved at the same time.

  19. Microwave synthesis and electrochemical characterization of Mn/Ni mixed oxide for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Prasankumar, T.; Jose, Sujin P., E-mail: sujamystica@yahoo.com [School of Physics, Madurai Kamaraj University, Madurai-625021, Tamil Nadu (India); Ilangovan, R.; Venkatesh, K. S. [Department of Nanoscience and Technology, Alagappa University, Karaikudi-630003, Tamil Nadu (India)

    2015-06-24

    Nanostructured Mn/Ni mixed metal oxide was synthesized at ambient temperature by facile microwave irradiation technique. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. X-ray diffraction analysis confirmed the formation of Mn/Ni mixed oxide in rhombohedral phase and the grain size calculated was found to be 87 nm. The irregular spherical morphology of the prepared sample was exhibited by the SEM images. The characteristic peaks of FTIR at about 630 cm{sup −1} and 749 cm{sup −1} were attributed to the Mn-O and Ni-O stretching vibrations respectively. The presence of both Mn and Ni in the prepared sample was validated by the EDS spectra which in turn confirmed the formation of mixed oxide. Cyclic voltammetry and galvanostatic chargedischarge measurements were employed to investigate the electrochemical performance of the mixed oxide. The cyclic voltammetry curves demonstrated good capacitive performance of the sample in the potential window −0.2V to 0.9V. The charge discharge study revealed the suitability of the prepared mixed oxide for the fabrication of supercapacitor electrode.

  20. Photocatalytic Oxidation of Sulfurous Acid in an Aqueous Medium

    Science.gov (United States)

    Romero, Alicia; Hernandez, Willie; Suarez, Marco F.

    2005-01-01

    The effect of some parameters on sulfurous acid and sulfur oxidation kinetics such as initial concentration of sulfurous acid, oxygen, TiO[2] crystalline concentration, the power of black light, and quantity of TiO[2] is investigated. The experiments can be performed in an undergraduate physical chemistry laboratory with an inexpensive…

  1. Photocatalytic Oxidation of Sulfurous Acid in an Aqueous Medium

    Science.gov (United States)

    Romero, Alicia; Hernandez, Willie; Suarez, Marco F.

    2005-01-01

    The effect of some parameters on sulfurous acid and sulfur oxidation kinetics such as initial concentration of sulfurous acid, oxygen, TiO[2] crystalline concentration, the power of black light, and quantity of TiO[2] is investigated. The experiments can be performed in an undergraduate physical chemistry laboratory with an inexpensive…

  2. Control of food intake by fatty acid oxidation and ketogenesis.

    Science.gov (United States)

    Scharrer, E

    1999-09-01

    Fatty acid oxidation seems to provide an important stimulus for metabolic control of food intake, because various inhibitors of fatty acid oxidation (mercaptoacetate, methyl palmoxirate, R-3-amino-4-trimethylaminobutyric acid) stimulated feeding in rats and/or mice, in particular when fed a fat-enriched diet, and long-term intravascular infusion of lipids reduced voluntary food intake in various species, including humans. The feeding response to decreased fatty acid oxidation was due to a shortening of the intermeal interval with meal size remaining unaffected. Thus, energy derived from fatty acid oxidation seems to contribute to control of the duration of postmeal satiety and meal onset. Since inhibition of glucose metabolism by 2-deoxy-D-glucose affects feeding pattern similarly, and spontaneous meals were shown to be preceded by a transient decline in blood glucose in rats and humans, a decrease in energy availability from glucose and fatty acid oxidation seems to be instrumental in eliciting eating. Since the feeding response of rats to inhibition of fatty acid oxidation was abolished by total abdominal vagotomy and pretreatment with capsaicin destroying non-myelinated afferents and attenuated by hepatic branch vagotomy, fatty acid oxidation in abdominal tissues, especially in the liver, apparently is signalled to the brain by vagal afferents to affect eating. Brain lesions and Fos immunohistochemistry were employed to identify pathways within the brain mediating eating in response to decreased fatty acid oxidation. According to these studies, the nucleus tractus solitarii (NTS) of the medulla oblongata represents the gate for central processing of vagally mediated afferent information related to fatty acid oxidation. The lateral parabrachial nucleus of the pons seems to be a major relay for pertinent ascending input from the NTS. In particular the central nucleus of the amygdala, a projection area of the parabrachial nucleus, appears to be crucial for eating

  3. Adsorption of ammonia on vanadium-antimony mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, Hernan; German, Estefania [Departamento e Instituto de Fisica del Sur, Universidad Nacional del Sur-CONICET, Avda. Alem 1253, (8000) Bahia Blanca (Argentina); Juan, Alfredo, E-mail: cajuan@uns.edu.ar [Departamento e Instituto de Fisica del Sur, Universidad Nacional del Sur-CONICET, Avda. Alem 1253, (8000) Bahia Blanca (Argentina); Irigoyen, Beatriz [Departamento de Ingenieria Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Pabellon de Industrias, Ciudad Universitaria, (1428) Ciudad Autonoma de Buenos Aires (Argentina)

    2012-02-01

    We analyzed the adsorption of ammonia (NH{sub 3}) on the VSbO{sub 4}(1 1 0) catalyst surface using density functional theory (DFT) calculations. We followed the evolution of the chemical bonds between different atoms of the resulting NH{sub 3}/VSbO{sub 4} system and the changes in the electronic structure of the catalyst. NH{sub 3} preferential adsorption geometries were analyzed through the crystal orbital overlap population (COOP) concept and the density of states (DOS) curves. The VSbO{sub 4}(1 1 0) surface exhibits Lewis and Bronsted acid sites on which the ammonia molecule can interact. On the Lewis acid site, NH{sub 3} adsorption resulted in the interaction between the N and a surface V-isolated cation. On Bronsted acid site, N interacted with a surface H coming from the chemical dissociation of water. The COOP analysis indicate that NH{sub 3} interaction on the VSbO{sub 4}(1 1 0) surface is weak. In addition, the DOS curves show more developed electronic interactions for NH{sub 3} adsorption on Lewis acid site than over Bronsted acid site.

  4. Kinetics of Oxidation of 3-Benzoylpropionic Acid by N-Chlorobenzamide in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    N. A. Mohamed Farook

    2011-01-01

    Full Text Available The kinetics of oxidation of 3-benzoylpropionic acid (KA by N-chlorobenzamide (NCB in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order dependence each in [KA], [NCB] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of benzamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. Hypochlorous acidium ion (H2O+Cl, has been postulated as the reactive oxidizing species. A mechanism consistent with observed results have been proposed and the related rate law deduced. The activation parameters have been computed with respect to slow step of the mechanism.

  5. Candida cloacae oxidation of long-chain fatty acids to dioic acids.

    Science.gov (United States)

    Green; Turner; Woodley

    2000-08-01

    Candida cloacae cells oxidize long-chain fatty acids to their corresponding dicarboxylic acids (dioic acids) at rates dependent on their chain length and degree of saturation. This is despite the well-known toxicity of the fatty acids. Among the saturated substrates, the oxidation is limited to lauric acid (C12). The addition of pristane (5% v/v), which acts as an inert carrier for the poorly water-soluble substrate, boosts the oxidation of lauric acid to a rate that is comparable to that of dodecane. When dissolved in pristane, myristic (C14) and palmitic (C16) acids are effective carbon sources for C. cloacae, but dioic acid production is very low. Media glucose concentration and pH also influence cell growth and productivity. After the glucose is depleted, oxidation is optimal at a low pH. A two-phase (pristane/water) reaction was tested in a 2-l stirred tank bioreactor in which growth and oxidation were separated. A 50% w/w conversion of lauric acid (10 g/l) to dodecanedioic acid was achieved. The bioreactor also alleviated poor mass transfer characteristics experienced in shake flasks.

  6. Dissolution study of thorium-uranium oxides in aqueous triflic acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bulemela, E.; Bergeron, A.; Stoddard, T. [Canadian Nuclear Laboratories - CNL, 286 Plant Rd., Chalk River, Ontario, K0J 1J0 (Canada)

    2016-07-01

    The dissolution of sintered mixed oxides of thorium with uranium in various concentrations of trifluoromethanesulfonic (triflic) acid solutions was investigated under reflux conditions to evaluate the suitability of the method. Various fragment sizes (1.00 mm < x < 7.30 mm) of sintered (Th,U)O{sub 2} and simulated high-burnup nuclear fuel (SIMFUEL) were almost completely dissolved in a few hours, which implies that triflic acid could be used as an alternative to the common dissolution method, involving nitric acid-hydrofluoric acid mixture. The influence of acid concentration, composition of the solids, and reaction time on the dissolution yield of Th and U ions was studied using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The dissolution rate was found to depend upon the triflic acid concentration and size of the solid fragments, with near complete dissolution for the smallest fragments occurring in boiling 87% w/w triflic acid. The formation of Th and U ions in solution appears to occur at the same rate as the triflic acid simultaneously reacts with the constituent oxides as evidenced by the results of a constant U/Th concentration ratio with the progress of the dissolution. (authors)

  7. Effect of Strong Acid Functional Groups on Electrode Rise Potential in Capacitive Mixing by Double Layer Expansion

    KAUST Repository

    Hatzell, Marta C.

    2014-12-02

    © 2014 American Chemical Society. The amount of salinity-gradient energy that can be obtained through capacitive mixing based on double layer expansion depends on the extent the electric double layer (EDL) is altered in a low salt concentration (LC) electrolyte (e.g., river water). We show that the electrode-rise potential, which is a measure of the EDL perturbation process, was significantly (P = 10-5) correlated to the concentration of strong acid surface functional groups using five types of activated carbon. Electrodes with the lowest concentration of strong acids (0.05 mmol g-1) had a positive rise potential of 59 ± 4 mV in the LC solution, whereas the carbon with the highest concentration (0.36 mmol g-1) had a negative rise potential (-31 ± 5 mV). Chemical oxidation of a carbon (YP50) using nitric acid decreased the electrode rise potential from 46 ± 2 mV (unaltered) to -6 ± 0.5 mV (oxidized), producing a whole cell potential (53 ± 1.7 mV) that was 4.4 times larger than that obtained with identical electrode materials (from 12 ± 1 mV). Changes in the EDL were linked to the behavior of specific ions in a LC solution using molecular dynamics and metadynamics simulations. The EDL expanded in the LC solution when a carbon surface (pristine graphene) lacked strong acid functional groups, producing a positive-rise potential at the electrode. In contrast, the EDL was compressed for an oxidized surface (graphene oxide), producing a negative-rise electrode potential. These results established the linkage between rise potentials and specific surface functional groups (strong acids) and demonstrated on a molecular scale changes in the EDL using oxidized or pristine carbons.

  8. Kinetics of Oxidation of Some Amino Acids by N-Chlorosaccharin in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    N. A. Mohamed Farook

    2004-01-01

    Full Text Available The kinetics of oxidation of some amino acids namely, glycine, alanine, aspartic acid, arginine, and histidine, (AA by N-chlorosaccharin (NCSA in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order in [AA], [NCSA] and of inverse fractional order in [H+]. The main product of the oxidation is the corresponding aldehyde. The ionic strength on the reaction rate has no significant effect. The effect of changing the dielectric constant of the medium on the rate indicates the reaction to be of dipole-dipole type. Hypochlorous acid has been postulated as the reactive oxidizing species. The reaction constants involved in the mechanism are derived. The activation parameters are computed with respect to slow step of the mechanism.

  9. Lactic acid production by mixed cultures of Kluyveromyces marxianus, Lactobacillus delbrueckii ssp. bulgaricus and Lactobacillus helveticus.

    Science.gov (United States)

    Plessas, S; Bosnea, L; Psarianos, C; Koutinas, A A; Marchant, R; Banat, I M

    2008-09-01

    Lactic acid production using Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) individually or as mixed culture on cheese whey in stirred or static fermentation conditions was evaluated. Lactic acid production, residual sugar and cell biomass were the main features examined. Increased lactic acid production was observed, when mixed cultures were used in comparison to individual ones. The highest lactic acid concentrations were achieved when K. marxianus yeast was combined with L. delbrueckii ssp. bulgaricus, and when all the strains were used revealing possible synergistic effects between the yeast and the two lactic acid bacteria. The same synergistic effects were further observed and verified when the mixed cultures were applied in sourdough fermentations, proving that the above microbiological system could be applied in the food fermentations where high lactic acid production is sought.

  10. Solvent-Free Selective Oxidation of Toluene with O2 Catalyzed by Metal Cation Modified LDHs and Mixed Oxides

    Directory of Open Access Journals (Sweden)

    Xiaoli Wang

    2016-01-01

    Full Text Available A series of metal cation modified layered-double hydroxides (LDHs and mixed oxides were prepared and used to be the selective oxidation of toluene with O2. The results revealed that the modified LDHs exhibited much higher catalytic performance than their parent LDH and the modified mixed oxides. Moreover, the metal cations were also found to play important roles in the catalytic performance and stabilities of modified catalysts. Under the optimal reaction conditions, the highest toluene conversion reached 8.7% with 97.5% of the selectivity to benzyldehyde; moreover, the catalytic performance remained after nine catalytic runs. In addition, the reaction probably involved a free-radical mechanism.

  11. Oxidative stabilization of mixed mayonnaises made with linseed oil and saturated medium-chain triglyceride oil.

    Science.gov (United States)

    Raudsepp, Piret; Brüggemann, Dagmar A; Lenferink, Aufried; Otto, Cees; Andersen, Mogens L

    2014-01-01

    Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during storage was lower in mixed mayonnaise compared to LSO mayonnaise, while in mixed oil mayonnaise the level of peroxides was constantly low. Mixed oil mayonnaise had a lower rate of oxygen consumption than mixed mayonnaise, LSO mayonnaise having the highest rate. The decay of water-soluble nitroxyl radicals showed radicals are formed in the aqueous phase with the same rate independent of the lipids. This was also reflected in decay of α-tocopherol during storage being similar in MCT and LSO mayonnaises, but being stable in mixed oil mayonnaise and mixed mayonnaise. Results suggest that other effects than simply diluting unsaturated triglycerides with saturated triglycerides is causing the oxidative stabilization observed for mixed mayonnaise and mixed oil mayonnaise. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. DRIFT study of CuO-CeO₂-TiO₂ mixed oxides for NOx reduction with NH₃ at low temperatures.

    Science.gov (United States)

    Chen, Lei; Si, Zhichun; Wu, Xiaodong; Weng, Duan

    2014-06-11

    A CuO-CeO2-TiO2 catalyst for selective catalytic reduction of NOx with NH3 (NH3-SCR) at low temperatures was prepared by a sol-gel method and characterized by X-ray diffraction, Brunner-Emmett-Teller surface area, ultraviolet-visible spectroscopy, H2 temperature-programmed reduction, scanning electron microscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The CuO-CeO2-TiO2 ternary oxide catalyst shows excellent NH3-SCR activity in a low-temperature range of 150-250 °C. Lewis acid sites generated from Cu(2+) are the main active sites for ammonia activation at low temperature, which is crucial for low temperature NH3-SCR activity. The introduction of ceria results in increased reducibility of CuO species and strong interactions between CuO particles with the matrix. The interactions between copper, cerium and titanium oxides lead to high dispersion of metal oxides with increased active oxygen and enhanced catalyst acidity. Homogeneously mixed metal oxides facilitate the "fast SCR" reaction among Cu(2+)-NO, nitrate (coordinated on cerium sites) and ammonia (on titanium sites) on the CuO-CeO2-TiO2 catalyst at low temperatures.

  13. Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid base properties on the oxidation of isopropanol

    Energy Technology Data Exchange (ETDEWEB)

    Meira, D.M.; Cortez, G.G. [Faculdade de Engenharia Quimica de Lorena, Lorena, SP (Brazil). Dept. de Engenharia Quimica. Lab. de Catalise II]. E-mail: cortez@dequi.faenquil.br; Monteiro, W.R.; Rodrigues, J.A.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Combustao e Propulsao]. E-mail: jajr@lcp.inpe.br

    2006-07-15

    Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K{sub 2}CO{sub 3} as precipitant. The decomposition of these hydrotalcite precursors at 450 deg C yielded homogeneous MgyAlOx mixed oxides that contain the Al{sup +3} cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR) and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V{sup +5} decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene. (author)

  14. Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid-base properties on the oxidation of isopropanol

    Directory of Open Access Journals (Sweden)

    D. M. Meira

    2006-09-01

    Full Text Available Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450°C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene.

  15. The Aerobic Oxidation of Bromide to Dibromine Catalyzed by Homogeneous Oxidation Catalysts and Initiated by Nitrate in Acetic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Partenheimer, Walt; Fulton, John L.; Sorensen, Christina M.; Pham, Van Thai; Chen, Yongsheng

    2014-06-01

    A small amount of nitrate, ~0.002 molal, initiates the Co/Mn catalyzed aerobic oxidation of bromide compounds (HBr,NaBr,LiBr) to dibromine in acetic acid at room temperature. At temperatures 40oC or less , the reaction is autocatalytic. Co(II) and Mn(II) themselves and mixed with ionic bromide are known homogeneous oxidation catalysts. The reaction was discovered serendipitously when a Co/Br and Co/Mn/Br catalyst solution was prepared for the aerobic oxidation of methyaromatic compounds and the Co acetate contained a small amount of impurity i.e. nitrate. The reaction was characterized by IR, UV-VIS, MALDI and EXAFS spectroscopies and the coordination chemistry is described. The reaction is inhibited by water and its rate changed by pH. The change in these variables, as well as others, are identical to those observed during homogeneous, aerobic oxidation of akylaromatics. A mechanism is proposed. Accidental addition of a small amount of nitrate compound into a Co/Mn/Br/acetic acid mixture in a large, commercial feedtank is potentially dangerous.

  16. Active oxygen by Ce–Pr mixed oxide nanoparticles outperform diesel soot combustion Pt catalysts

    OpenAIRE

    Guillén Hurtado, Noelia; Garcia-Garcia, Avelina; Bueno López, Agustín

    2015-01-01

    A Ce0.5Pr0.5O2 mixed oxide has been prepared with the highest surface area and smallest particle size ever reported (125 m2/g and 7 nm, respectively), also being the most active diesel soot combustion catalyst ever tested under realistic conditions if catalysts forming highly volatile species are ruled out. This Ce–Pr mixed oxide is even more active than a reference platinum-based commercial catalyst. This study provides an example of the efficient participation of oxygen species released by ...

  17. Mg-AI Mixed Oxides Supported Bimetallic Au-Pd Nanoparticles with Superior Catalytic Properties in Aerobic Oxidation of Benzyl Alcohol and Glycerol

    Institute of Scientific and Technical Information of China (English)

    王亮; 张伟; 曾尚景; 苏党生; 孟祥举; 肖丰收

    2012-01-01

    Nano-sized Au and Pd catalysts are favorable for oxidations with molecular oxygen, and the preparation of this kind of nanoparticles with high catalytic activities is strongly desirable. We report a successful synthesis of bimetal- lic Au-Pd nanoparticles with rich edge and comer sites on unique support of Mg-AI mixed oxides (Au-Pd/MAO), which are favorable for producing metal nanoparticles with high degree of coordinative unsaturation of metal atoms The systematic microscopic characterizations confirm the bimetallic Au-Pd nanoparticles are present as Au-Pd alloy The irregular shape of the bimetallic nanoparticles are directly observed in HRTEM images. As we expected, Au-Pd/MAO gives very excellent catalytic performances in the aerobic oxidation of benzyl alcohol and glycerol. For example, Au-Pd/MAO shows very high TOF of 91000 h i at 433 K with molecular oxygen at air pressure in solvent-free oxidation of benzyl alcohol; this catalyst also shows relatively high selectivity for tartronic acid (TA- RAC, 36.6%) at high conversion (98.5%) in aerobic oxidation of glycerol. The superior catalytic properties of Au-Pd/MAO would be potentially important tbr production of fine chemicals.

  18. Destruction of hazardous and mixed wastes using mediated electrochemical oxidation in a Ag(II)HNO3 bench scale system

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, B.; Chiba, Z.; Hsu, P.; Lewis, P.; Murguia, L.; Adamson, M.

    1997-02-01

    Mediated Electrochemical Oxidation (MEO) is a promising technology for the destruction of organic containing wastes and the remediation of mixed wastes containing transuranic components. The combination of a powerful oxidant and an acid solution allows the conversion of nearly all organics, whether present in hazardous or in mixed waste, to carbon dioxide. Insoluble transuranics are dissolved in this process and may be recovered by separation and precipitation. The oxidant, or mediator, is a multivalent transition metal ion which is cleanly recycled in a number of charge transfer steps in an electrochemical cell. The MEO technique offers several advantages which are inherent in the system. First, the oxidation/dissolution processes are accomplished at near ambient pressures and temperatures (30-70{degrees}C). Second, all waste stream components and oxidation products (with the exception of evolved gases) are contained in an aqueous environment. This electrolyte acts as an accumulator for inorganics which were present in the original waste stream, and the large volume of electrolyte provides a thermal buffer for the energy released during oxidation of the organics. Third, the generation of secondary waste is minimal, as the process needs no additional reagents. Finally, the entire process can be shut down by simply turning off the power, affording a level of control unavailable in some other techniques. Although the oxidation of organics and the dissolution of transuranics by higher valency metal ions has been known for some time, applying the MEO technology to waste treatment is a relatively recent development. Numerous groups, both in the United States and Europe, have made substantial progress in the last decade towards understanding the mechanistic pathways, kinetics, and engineering aspects of the process. At Lawrence Livermore National Laboratory, substantial contributions have been made to this knowledge base in these areas and others. Conceptual design and

  19. Formic Acid Oxidation at Platinum-Bismuth Clusters

    DEFF Research Database (Denmark)

    Lovic, J. D.; Stevanovic, S. I.; Tripkovic, D. V.

    2014-01-01

    Formic acid oxidation was studied on platinum-bismuth deposits on glassy carbon (GC) substrate. The catalysts of equimolar ratio were prepared by potentiostatic deposition using chronocoulometry. Bimetallic structures obtained by two-step process, comprising deposition of Bi followed by deposition...... of Pt, were characterized by AFM spectroscopy which indicated that Pt crystallizes preferentially onto previously formed Bi particles. The issue of Bi leaching (dissolution) from PtBi catalysts, and their catalytic effect alongside the HCOOH oxidation is rather unresolved. In order to control Bi...... dissolution, deposits were subjected to electrochemical oxidation, in the relevant potential range and supporting electrolyte, prior to use as catalysts for HCOOH oxidation. Anodic striping charges indicated that along oxidation procedure most of deposited Bi was oxidized. ICP mass spectroscopy analysis...

  20. Visibly transparent and radiopaque inorganic organic composites from flame-made mixed-oxide fillers

    Energy Technology Data Exchange (ETDEWEB)

    Maedler, Lutz [University of California, Los Angeles, Department of Chemical Engineering (United States)], E-mail: lutz@seas.ucla.edu; Krumeich, Frank [Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences (Switzerland); Burtscher, Peter; Moszner, Norbert [Ivoclar Vivadent AG (Liechtenstein)

    2006-08-15

    Radiopaque composites have been produced from flame-made ytterbium/silica mixed oxide within a crosslinked methacrylate resin matrix. The refractive index of the filler powder increased with ytterbium oxide loading. A high transparency was achieved for a matching refractive index of the filler powder and the polymer in comparison to commercial materials with 52 wt% ceramic filling. It was demonstrated that powder homogeneity with regard to particle morphology and distribution of the individual metal atoms is essential to obtain a highly transparent composite. In contrast, segregation of crystalline single-oxide phases drastically decreased the composite transparency despite similar specific surface areas, refractive indices and overall composition. The superior physical strength, transparency and radiopacity compared to composites made from conventional silica based-fillers makes the flame-made mixed-oxide fillers especially attractive for dental restoration materials.

  1. Storage capacity and oxygen mobility in mixed oxides from transition metals promoted by cerium

    Science.gov (United States)

    Perdomo, Camilo; Pérez, Alejandro; Molina, Rafael; Moreno, Sonia

    2016-10-01

    The oxygen mobility and storage capacity of Ce-Co/Cu-MgAl or Ce-MgAl mixed oxides, obtained by hydrotalcite precursors, were evaluated using Toluene-temperature-programmed-reaction, 18O2 isotopic exchange and O2-H2 titration. The presence of oxygen vacancies-related species was evaluated by means of Electron Paramagnetic Resonance. A correlation was found between the studied properties and the catalytic activity of the oxides in total oxidation processes. It was evidenced that catalytic activity depends on two related processes: the facility with which the solid can be reduced and its ability to regenerate itself in the presence of molecular oxygen in the gas phase. These processes are enhanced by Cu-Co cooperative effect in the mixed oxides. Additionally, the incorporation of Ce in the Co-Cu catalysts improved their oxygen transport properties.

  2. Visibly transparent & radiopaque inorganic organic composites from flame-made mixed-oxide fillers

    Science.gov (United States)

    Mädler, Lutz; Krumeich, Frank; Burtscher, Peter; Moszner, Norbert

    2006-08-01

    Radiopaque composites have been produced from flame-made ytterbium/silica mixed oxide within a crosslinked methacrylate resin matrix. The refractive index of the filler powder increased with ytterbium oxide loading. A high transparency was achieved for a matching refractive index of the filler powder and the polymer in comparison to commercial materials with 52 wt% ceramic filling. It was demonstrated that powder homogeneity with regard to particle morphology and distribution of the individual metal atoms is essential to obtain a highly transparent composite. In contrast, segregation of crystalline single-oxide phases drastically decreased the composite transparency despite similar specific surface areas, refractive indices and overall composition. The superior physical strength, transparency and radiopacity compared to composites made from conventional silica based-fillers makes the flame-made mixed-oxide fillers especially attractive for dental restoration materials.

  3. Ni–Ta–O mixed oxide catalysts for the low temperature oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo

    2015-09-01

    The "wet" sol-gel and "dry" solid-state methods were used to prepare Ni-Ta-O mixed oxide catalysts. The resulting Ni-Ta oxides exhibit high activity and selectivity for the low temperature oxidative dehydrogenation of ethane to ethylene. The Ta/(Ni + Ta) atomic ratios (varying from 0 to 0.11 in "wet" sol-gel method, and from 0 to 0.20 in "dry" solid-state method) as well as the preparation methods used in the synthesis, play important roles in controlling catalyst structure, activity, selectivity and stability in the oxidative dehydrogenation of ethane. Electron microscopy characterizations (TEM, EELS mapping, and HAADF-STEM) clearly demonstrate that the Ta atoms are inserted into NiO crystal lattice, resulting in the formation of a new Ni-Ta oxide solid solution. More Ta atoms are found to be located at the lattice sites of crystal surface in sol-gel catalyst. While, a small amount of thin layer of Ta2O5 clusters are detected in solid-state catalyst. Further characterization by XRD, N2 adsorption, SEM, H2-TPR, XPS, and Raman techniques reveal different properties of these two Ni-Ta oxides. Due to the different properties of the Ni-Ta oxide catalysts prepared by two distinct approaches, they exhibit different catalytic behaviors in the ethane oxidative dehydrogenation reaction at low temperature. Thus, the catalytic performance of Ni-Ta-O mixed oxide catalysts can be systematically modified and tuned by selecting a suitable synthesis method, and then varying the Ta content. ©2015 Elsevier Inc. All rights reserved.

  4. Magnetic behavior of Mg-Al-Zn-Fe mixed oxides from precursors layered double hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, M.I., E-mail: marcosivanoliva@gmail.com [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, M. Allende y H. de la Torre Ciudad Universitaria, 5000 Cordoba (Argentina); IFFAM AF (CONICET - FaMAF UNC), M. Allende y H. de la Torre Ciudad Universitaria, 5000 Cordoba (Argentina); Heredia, A. [CITeQ - Facultad R. Cordoba, Universidad Tecnologica Nacional Maestro Lopez esq. Cruz Roja Argentina, CP 5016 Cordoba (Argentina); Zandalazini, C.I. [Centro Laser de Ciencias Moleculares. INFIQC-FCQ-Grupo de Ciencia de Materiales-FaMAF-Universidad Nacional de Cordoba, Ciudad Universitaria, CP5000 Cordoba, Argentina CONICET (Argentina); Crivello, M. [CITeQ - Facultad R. Cordoba, Universidad Tecnologica Nacional Maestro Lopez esq. Cruz Roja Argentina, CP 5016 Cordoba (Argentina); Corchero, E. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, M. Allende y H. de la Torre Ciudad Universitaria, 5000 Cordoba (Argentina)

    2012-08-15

    Mixed oxides of Mg-Al-Zn-Fe were obtained by calcination of layered double hydroxides (LDH) prepared by coprecipitation reaction with hydrothermal treatment. The structural characterization of precursors and oxides was carried out by X rays diffraction, showing increases of ZnO phase with the increase of the zinc content. Magnetic behavior was studied by vibrating sample magnetometer (VSM) and by a superconducting quantum interference device (SQUID) showing both paramagnetic and super paramagnetic behavior depending on both particles size and composition.

  5. Free acetate production by rat hepatocytes during peroxisomal fatty acid and dicarboxylic acid oxidation.

    Science.gov (United States)

    Leighton, F; Bergseth, S; Rørtveit, T; Christiansen, E N; Bremer, J

    1989-06-25

    The fate of the acetyl-CoA units released during peroxisomal fatty acid oxidation was studied in isolated hepatocytes from normal and peroxisome-proliferated rats. Ketogenesis and hydrogen peroxide generation were employed as indicators of mitochondrial and peroxisomal fatty acid oxidation, respectively. Butyric and hexanoic acids were employed as mitochondrial substrates, 1, omega-dicarboxylic acids as predominantly peroxisomal substrates, and lauric acid as a substrate for both mitochondria and peroxisomes. Ketogenesis from dicarboxylic acids was either absent or very low in normal and peroxisome-proliferated hepatocytes, but free acetate release was detected at rates that could account for all the acetyl-CoA produced in peroxisomes by dicarboxylic and also by monocarboxylic acids. Mitochondrial fatty acid oxidation also led to free acetate generation but at low rates relative to ketogenesis. The origin of the acetate released was confirmed employing [1-14C]dodecanedioic acid. Thus, the activity of peroxisomes might contribute significantly to the free acetate generation known to occur during fatty acid oxidation in rats and possibly also in humans.

  6. A method for measuring fatty acid oxidation in C. elegans

    DEFF Research Database (Denmark)

    Elle, Ida Coordt; Rødkær, Steven Vestergaard; Fredens, Julius;

    2012-01-01

    The nematode C. elegans has during the past decade proven to be a valuable model organism to identify and examine molecular mechanisms regulating lipid storage and metabolism. While the primary approach has been to identify genes and pathways conferring alterations in lipid accumulation, only a few...... recent studies have recognized the central role of fatty acid degradation in cellular lipid homeostasis. In the present study, we show how complete oxidation of fatty acids can be determined in live C. elegans by examining oxidation of tritium-labeled fatty acids to tritiated H2O that can be measured......, the present methodology can be used to delineate the role of specific genes and pathways in the regulation of β-oxidation in C. elegans....

  7. Mixed cultures of Kimchi lactic acid bacteria show increased cell ...

    African Journals Online (AJOL)

    ufuoma

    kimchi lactobacilli on batch fermentation increased the cell density and lactic acid production with low nutrients .... first series of fermentations were carried out using pure cultures of each ... Each number represents the mean. ± SD of three ...

  8. Role of tartaric and malic acids in wine oxidation.

    Science.gov (United States)

    Danilewicz, John C

    2014-06-04

    Tartaric acid determines the reduction potential of the Fe(III)/Fe(II) redox couple. Therefore, it is proposed that it determines the ability of Fe to catalyze wine oxidation. The importance of tartaric acid was demonstrated by comparing the aerial oxidation of 4-methylcatechol (4-MeC) in model wine made up with tartaric and acetic acids at pH 3.6. Acetic acid, as a weaker Fe(III) ligand, should raise the reduction potential of the Fe couple. 4-MeC was oxidized in both systems, but the mechanisms were found to differ. Fe(II) readily reduced oxygen in tartrate model wine, but Fe(III) alone failed to oxidize the catechol, requiring sulfite assistance. In acetate model wine the reverse was found to operate. These observations should have broad application to model systems designed to study the oxidative process in foods and other beverages. Consideration should be given to the reduction potential of metal couples by the inclusion of appropriate ligands.

  9. 78 FR 9431 - Shaw AREVA MOX Services, LLC (Mixed Oxide Fuel Fabrication Facility); Order Approving Indirect...

    Science.gov (United States)

    2013-02-08

    ... COMMISSION [NRC-2011-0081; Docket No. 70-3098; Construction Authorization No. CAMOX-001] Shaw AREVA MOX... Construction Authorization I Shaw AREVA MOX Services, LLC (MOX Services) holds Construction ] Authorization (CA) CAMOX-001 for construction of a Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF) at the...

  10. 76 FR 22735 - Shaw AREVA MOX Services, Mixed Oxide Fuel Fabrication Facility; License Amendment Request, Notice...

    Science.gov (United States)

    2011-04-22

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Shaw AREVA MOX Services, Mixed Oxide Fuel Fabrication Facility; License Amendment Request, Notice.... Introduction The NRC has received, by letter dated February 8, 2011, an amendment request from Shaw AREVA...

  11. Nickel/magnesium-lanthanum mixed oxide catalyst in the Kumada-coupling.

    Science.gov (United States)

    Kiss, Arpád; Hell, Zoltán; Bálint, Mária

    2010-01-21

    A new, heterogeneous, magnesium-lanthanum mixed oxide solid base-supported nickel(ii) catalyst was developed. The catalyst was used successfully in the Kumada coupling of aryl halides, especially aryl bromides. The optimal reaction conditions of the coupling were determined.

  12. A study of oxygen transport in mixed conducting oxides using isotopic exchange and conductivity relaxation

    NARCIS (Netherlands)

    Otter, den Matthijs Willem

    2000-01-01

    Mixed conducting oxygen ion conductors can be applied as membranes for the separation of oxygen from air, as electrodes for both oxygen pumps and solid oxide fuel cells. In these applications, oxygen molecules dissociate on the surface of the material. The atomic oxygen species pick up two electrons

  13. Transport processes in mixed conducting oxides: combining time domain experiments and frequency domain analysis

    NARCIS (Netherlands)

    Boukamp, Bernard A.; Otter, den Matthijs W.; Bouwmeester, Henny J.M.

    2004-01-01

    The conductivity relaxation (CR) method is often used for measuring the surface transfer rate, Ktr, and the bulk diffusion coefficient, $$\\tilde{D},$$ for oxygen transport in mixed conducting oxides (MIECs). The time domain analysis of the obtained CR response is rather complex and is based on lsquo

  14. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    Science.gov (United States)

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.

    2004-01-01

    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  15. Oxidation in fish oil enriched mayonnaise: ascorbic acid and low pH increase oxidative deterioration.

    Science.gov (United States)

    Jacobsen, C; Timm, M; Meyer, A S

    2001-08-01

    The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil-water interface into the aqueous phase at all pH levels, but this effect of ascorbic acid was strongest at low pH (pH 3.8-4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced due to the reduction of Fe(3+) to Fe(2+) that rapidly catalyzes lipid oxidation via lipid hydroperoxide decomposition at the oil-water interface in mayonnaise.

  16. Electrospun mixed oxide photocatalysts to decompose dyes in water

    Science.gov (United States)

    Divya, Sherlyn

    In this work, four catalysts have been studied for their photocatalytic efficiency by testing each with methylene blue dye solution. Three catalysts were synthesized by the electrospinning method and then compared with the fourth commercially available catalyst for their photocatalytic activity. The basic metal oxide studied was titanium dioxide. Nanocomposite mats of pure titania, copper doped titania and copper doped degussa P25 titania, were synthesized using the electrospinning method. The pure titania and copper doped titania nanocomposites possessed the anatase phase which was obtained by annealing the as-spun nanocomposites at 4500C. All the catalysts were analyzed for their photocatalytic activity both under ultra-violet light and under visible light. The aim of this work was to synthesize titania photocatalysts, demonstrate their photocatalytic activity with methylene blue solution under UV-light and visible light and compare their activities with the commercial titanium dioxide (degussa P25). It is important to synthesize visible light active photocatalysts as these could be activated under a wide spectrum of natural sunlight unlike the degussa titanium dioxide. Doping was incorporated in order to narrow the band gap energy of the photocatalyst for achieving higher efficiency especially under visible light irradiation. The morphology and size of the synthesized photocatalysts were studied by characterizing them with Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, Transmission Electron Microscopy and X-Ray Diffraction. The photocatalytic activity tests were carried out using UV-Vis Spectroscopy. It was found that the electrospun pure titania and copper doped titania fibers were activated under the visible light spectrum unlike the degussa titanium dioxide. The copper doped titania provided to be the most efficient photocatalyst under visible light radiation and the importance of this finding can be extended for treating industrial

  17. Superconducting Hg-Based Mixed Oxides and Oxyfluorides

    Science.gov (United States)

    Antipov, E. V.

    2000-09-01

    Syntheses under high pressure and under controlled mercury and oxygen partial pressures of different members of the HgBa2Can-1CunO2n+2+δ series have been developed. There are two main parameters influencing Tc in this family: width of a perovskite slab (n) and concentration (δ) of the extra oxygen located in the Hg layer. The increase of Tc with n occurs until the third member, while after that it decreases. All the members of the series exhibit similar cupola shaped dependencies of Tc vs. δ. Strongly overdoped high members of the series with n = 3-5 were prepared only using high pressure technique and BaO2 as an internal oxidizer. Neutron powder diffraction experiments were carried out for monophase oxygenated HgBa2CuO4F4+δ and fluorinated HgBa2CuO4Fδ samples with different extra oxygen or fluorine content and Tc values. Fluorinated series also exhibits the cupola -like behavior for the Tc vs. δ dependence. NPD showed twice the amount of extra fluorine in comparison with those for the oxygenated Hg-1201 phases with close Tc's. The exchange of the extra oxygen by double amount of fluorine causes shortening of the apical Cu-O distances, while the in-plane ones, as well as Tc, do not vary. The influence of the external pressure on the structure and Tc of Hg-1201 strongly depends on the doping level. The increase of the extra oxygen content on going from underdoped to overdoped state results in the larger compression of the apical Cu-O and Ba-OHg distances while the HgO2 dumbbell as well as the distance between Ba and O from the (CuO2) layers becomes practically pressure independent. These results together with the data for fluorinated materials allow to elucidate the crucial structural features responsible for the Tc variation under high pressure.

  18. Mixed-phase PdRu bimetallic structures with high activity and stability for formic acid electrooxidation.

    Science.gov (United States)

    Wu, Dongshuang; Zheng, Zhaoliang; Gao, Shuiying; Cao, Minna; Cao, Rong

    2012-06-14

    Aiming at investigating the effect of structure on electrocatalytic properties, Pd(50)Ru(50) nanoparticles (NPs) with three different structures were carefully designed in a one-pot polyol process for application in formic acid electrooxidation. The three structures are: (1) single-phase PdRu nanodendrites (denoted as PR-1), (2) a mixed-phase mixture of PdRu nanodendrites and monometallic Ru NPs (denoted as PR-2), and (3) a mixed-phase mixture of monometallic Pd and Ru NPs (denoted as PR-3). From PR-1 to PR-3, the structure was varied from single-phase to mixed-phase. The relative position of Ru was altered from completely Pd-connected (PR-1), to a mixture of Pd-connected and monometallic (PR-2), and completely monometallic (PR-3). All PdRu NPs outperform the commercial Pd/C. PR-2 exhibits the highest peak current density, but its stability is slightly lower than that of PR-3. When both the current density and the durability are taken into consideration, PR-2 is the best choice of catalyst for formic acid oxidation. It indicates that both the Pd-connected Ru NPs and monometallic Ru NPs in the mixed-phase PR-2 are essential to improve the electrocatalytic properties. Our study also illustrates that the electrochemical active surface area (ECSA) and hydrogen storage capacity of the as-prepared PdRu NPs are greatly enhanced after several hundred scans in formic acid, indicating the possibility for highly restorable catalysts in direct formic acid fuel cells.

  19. Mixed acid-base disorder secondary to topiramate use in traumatic brain injury

    Directory of Open Access Journals (Sweden)

    S Golla

    2016-01-01

    Full Text Available We report a case of a man with traumatic brain injury. He was started on to prophylactic topiramate which led to a mixed acid-base disorder. He had severe metabolic acidosis secondary to renal tubular acidification defect and respiratory alkalosis secondary to hyperventilation. Withdrawal of the offending drug led to the prompt resolution of the acid-base disturbance.

  20. Alcohol production through volatile fatty acids reduction with hydrogen as electron donor by mixed cultures

    NARCIS (Netherlands)

    Steinbusch, K.J.J.; Hamelers, H.V.M.; Buisman, C.J.N.

    2008-01-01

    In this research we demonstrated a new method to produce alcohols. It was experimentally feasible to produce ethanol, propanol and butanol from solely volatile fatty acids (VFAs) with hydrogen as electron donor. In batch tests, VFAs such as acetic, propionic and butyric acids were reduced by mixed m

  1. alpha-Lipoic acid and ascorbate prevent LDL oxidation and oxidant stress in endothelial cells.

    Science.gov (United States)

    Sabharwal, Anup K; May, James M

    2008-02-01

    Both alpha-lipoic acid (LA) and ascorbic acid (vitamin C) have been shown to improve endothelial dysfunction, a precursor of atherosclerosis. Since oxidant stress can cause endothelial dysfunction, we tested the interaction and efficacy of these antioxidants in preventing oxidant damage to lipids due to both intra- and extracellular oxidant stresses in EA.hy926 endothelial cells. LA spared intracellular ascorbate in culture and in response to an intracellular oxidant stress induced by the redox cycling agent menadione. Extracellular oxidant stress generated by incubating cells for 2 h in with 0.2 mg/ml LDL and 5 muM Cu2+ caused a time-dependent increase of the lipid peroxidation product malondialdehyde in both cells and LDL, preceded by rapid disappearance of; alpha-tocopherol in LDL. alpha-Lipoic acid at concentrations of 40-80 microM blunted these effects. Similarly, intracellular ascorbate concentrations of 1-2 mM also prevented Cu2+-induced lipid peroxidation in LDL and cells. Cu2+-dependent oxidation of LDL in the presence of ascorbate-loaded cells decreased intracellular ascorbate by 20%, but this decrease was not reversed by LA. Both LA and ascorbate protect endothelial cells and LDL from either intra- or extracellular oxidant stress, but that LA does not spare ascorbate in oxidatively stressed cells.

  2. Partial oxidation of methane to syngas in a mixed-conducting oxygen permeable membrane reactor

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Mixed-conducting oxygen permeable membranes represent a class of novel ceramic membranes, which exhibit mixed oxygen ionic and electronic conductivities. At high temperatures, oxygen can permeate through the membrane from the high to low oxygen pressure side under an oxygen concentration gradient. Theoretically, the permselectivity of oxygen is 100%. Recently, a novel mixed-conducting membrane--Ba0.5Sr0.5Co0.8Fe0.2O3-δ has been developed, which shows extremely high oxygen permeability and promising stability. Furthermore, the reactor made with such membranes was successfully applied to the partial oxidation of methane to syngas reaction using air as the oxygen source, which realized the coupling of the separation of oxygen from air and the partial oxidation of membrane reaction in one process. At 850℃, methane conversion >88%, CO selectivity >97% and oxygen permeation rate of about 7.8 mL/(cm2.min) were obtained.

  3. Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

    Energy Technology Data Exchange (ETDEWEB)

    Schacht, L. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Ciencia de Materiales, Av. IPN s/n, Edificio 9, Col. Lindavista, 07738 Mexico D. F. (Mexico); Navarrete, J.; Schacht, P.; Ramirez, M. A., E-mail: pschacha@imp.m [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas No. 152, 07730 Mexico D. F. (Mexico)

    2010-07-01

    V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

  4. Bimetallic bonding and mixed oxide formation in the Ga-Pd-CeO2 system

    Science.gov (United States)

    Skála, Tomáš; Tsud, Nataliya; Prince, Kevin C.; Matolín, Vladimír

    2011-08-01

    The interaction of gallium and palladium with 2 nm CeO2(111) layers grown on Cu(111) was studied by core level photoelectron spectroscopy and resonant valence band spectroscopy. Palladium alone interacted weakly with ceria layers. Gallium deposited on cerium dioxide formed a mixed Ga2O3-Ce2O3 oxide of 1:1 stoichiometry (cerium gallate CeGaO3), with both metals in the M3+ oxidation state. Increasing Ga coverages led to the formation of lower oxidation states, i.e., Ga1+ in Ga2O oxide and metallic Ga0. Palladium deposited onto this complex system interacted with gallium leading to a breakage of Ga-ceria bonds, a decrease of the oxidation state of gallium, and formation of a Ga-Pd intermetallic alloy in which all components (CeO2, CeGaO3, Ga2O, Ga-Pd, and Pd) are in equilibrium.

  5. Acetylsalicylic acid and acetaminophen protect against oxidative neurotoxicity.

    Science.gov (United States)

    Maharaj, H; Maharaj, D S; Daya, S

    2006-09-01

    Due to the implication of oxidative stress in neurodegenerative disorders we decided to investigate the antioxidant properties of acetylsalicylic acid and acetaminophen either alone or in combination. The thiobarbituric acid assay (TBA) and the nitroblue tetrazolium (NBT) assay were used to investigate quinolinic acid (QA)-induced: lipid peroxidation and superoxide anion generation in the rat hippocampus, in vivo. The study also shows, using cresyl violet staining, the preservation of structural integrity of neuronal cells following treatment with acetylsalicylic acid and acetaminophen in QA-lesioned rat hippocampus. Furthermore the study sought to determine whether these agents have any effect on endogenous (QA) formation. This study shows that acetylsalicylic acid and acetaminophen inhibit QA-induced superoxide anion generation, lipid peroxidation and cell damage, in vivo, in the rat hippocampus. In addition these agents inhibit the enzyme, 3-hydroxyanthranilic acid oxygenase (3-HAO), responsible for the synthesis of endogenous QA.

  6. Characterization of sulfur oxidizing bacteria related to biogenic sulfuric acid corrosion in sludge digesters.

    Science.gov (United States)

    Huber, Bettina; Herzog, Bastian; Drewes, Jörg E; Koch, Konrad; Müller, Elisabeth

    2016-07-18

    Biogenic sulfuric acid (BSA) corrosion damages sewerage and wastewater treatment facilities but is not well investigated in sludge digesters. Sulfur/sulfide oxidizing bacteria (SOB) oxidize sulfur compounds to sulfuric acid, inducing BSA corrosion. To obtain more information on BSA corrosion in sludge digesters, microbial communities from six different, BSA-damaged, digesters were analyzed using culture dependent methods and subsequent polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). BSA production was determined in laboratory scale systems with mixed and pure cultures, and in-situ with concrete specimens from the digester headspace and sludge zones. The SOB Acidithiobacillus thiooxidans, Thiomonas intermedia, and Thiomonas perometabolis were cultivated and compared to PCR-DGGE results, revealing the presence of additional acidophilic and neutrophilic SOB. Sulfate concentrations of 10-87 mmol/L after 6-21 days of incubation (final pH 1.0-2.0) in mixed cultures, and up to 433 mmol/L after 42 days (final pH sulfuric acid production potentials. Additionally, elevated sulfate concentrations in the corroded concrete of the digester headspace in contrast to the concrete of the sludge zone indicated biological sulfur/sulfide oxidation. The presence of SOB and confirmation of their sulfuric acid production under laboratory conditions reveal that these organisms might contribute to BSA corrosion within sludge digesters. Elevated sulfate concentrations on the corroded concrete wall in the digester headspace (compared to the sludge zone) further indicate biological sulfur/sulfide oxidation in-situ. For the first time, SOB presence and activity is directly relatable to BSA corrosion in sludge digesters.

  7. Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

    2001-01-01

    The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...... due to the reduction of Fe3+ to Fe2+ that rapidly catalyzes lipid oxidation via lipid hydroperoxide decomposition at the oil-water interface in mayonnaise...

  8. Storage capacity and oxygen mobility in mixed oxides from transition metals promoted by cerium

    Energy Technology Data Exchange (ETDEWEB)

    Perdomo, Camilo [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia); Pérez, Alejandro [Grupo de Investigación Fitoquímica (GIFUJ), Departamento de Química, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C (Colombia); Molina, Rafael [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia); Moreno, Sonia, E-mail: smorenog@unal.edu.co [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia)

    2016-10-15

    Highlights: • Ce addition to the catalysts improves the availability of oxygen in the materials. • Mixed oxide with Co and Cu exhibits the best oxygen transport properties. • Co presence improves O{sub 2} mobility in the catalysts. • The presence of Cu in the solids improves redox properties. - Abstract: The oxygen mobility and storage capacity of Ce-Co/Cu-MgAl or Ce–MgAl mixed oxides, obtained by hydrotalcite precursors, were evaluated using Toluene-temperature-programmed-reaction, {sup 18}O{sub 2} isotopic exchange and O{sub 2}-H{sub 2} titration. The presence of oxygen vacancies-related species was evaluated by means of Electron Paramagnetic Resonance. A correlation was found between the studied properties and the catalytic activity of the oxides in total oxidation processes. It was evidenced that catalytic activity depends on two related processes: the facility with which the solid can be reduced and its ability to regenerate itself in the presence of molecular oxygen in the gas phase. These processes are enhanced by Cu-Co cooperative effect in the mixed oxides. Additionally, the incorporation of Ce in the Co-Cu catalysts improved their oxygen transport properties.

  9. Gill lesions and death of bluegill in an acid mine drainage mixing zone

    Energy Technology Data Exchange (ETDEWEB)

    Henry, T.B.; Irwin, E.R.; Grizzle, J.M.; Brumbaugh, W.G.; Wildhaber, M.L. [Auburn University, Auburn, AL (United States). Alabama Cooperative of Fish & Wildlife Research Unit

    2001-07-01

    The toxicity of an acid mine drainage (AMD) mixing zone was investigated by placing bluegill (Lepomis macrochirus) at the confluence of a stream contaminated by AMD and a stream having neutral pH. A mixing channel receiving water from both streams was assembled in the field, during July and October 1996, to determine the toxicity of freshly mixed and aged water (2.9-7.5 min). The AMD stream had elevated concentrations of Al and Fe, which precipitated upon mixing, and of Mn, which did not precipitate in the mixing zone. Fish exposed to freshly mixed water had higher mortality than fish exposed to water after aging. Precipitating Al, but not Fe, accumulated on the gills of bluegill, and accumulation was more rapid early during the mixing process than after aging. Fish exposed for 3.5 h to freshly mixed water had hypertrophy and hyperplasia of gill filament and lamellar epithelial cells. Similar lesions were observed after 6.0 h in fish exposed to water aged after mixing. Results demonstrated that Al was the predominant metal accumulating on the gills of fish in this AMD mixing zone, and that mixing zones can be more toxic than AMD streams in equilibrium.

  10. Fabrication of uranium–americium mixed oxide pellet from microsphere precursors: Application of CRMP process

    Energy Technology Data Exchange (ETDEWEB)

    Remy, E. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Picart, S., E-mail: sebastien.picart@cea.fr [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Delahaye, T. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Jobelin, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Lebreton, F.; Horlait, D. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Bisel, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Blanchart, P. [Heterogeneous Materials Research Group, Centre Européen de la Céramique, F-87068 Limoges (France); Ayral, A. [Institut Européen des Membranes, CNRS-ENSCM-UM2, CC47, University Montpellier 2, F-34095 Montpellier cedex 5 (France)

    2014-10-15

    Highlights: • Dust free process for (U,Am)O{sub 2} transmutation target fabrication. • Synthesis of U{sub 0.9}Am{sub 0.1}O{sub 2} mixed oxide microspheres from ion exchange resin. • Fabrication of dense U{sub 0.9}Am{sub 0.1}O{sub 2} pellet with 95% TD from mixed oxide microspheres. - Abstract: Mixed uranium–americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Recently, several processes have been developed in order to validate fabrication flowchart in terms of material specifications such as density and homogeneity but also to suggest simplifications for lowering industrial costs and hazards linked to dust generation of highly contaminating and irradiating compounds. This study deals with the application of an innovative route using mixed oxide microspheres obtained from metal loaded resin bead calcination, called Calcined Resin Microsphere Pelletization (CRMP). The synthesis of mixed oxide microsphere precursor of U{sub 0.9}Am{sub 0.1}O{sub 2±δ} is described as well as its characterisation. The use of this free-flowing precursor allows the pressing and sintering of one pellet of U{sub 0.9}Am{sub 0.1}O{sub 2±δ}. The ceramic obtained was characterised and results showed that its microstructure is dense and homogeneous and its density attains 95% of the theoretical density. This study validates the scientific feasibility of the CRMP process applied to the fabrication of uranium and americium-containing materials.

  11. Control of the optical properties of silicon and chromium mixed oxides deposited by reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Vergara, L., E-mail: vergara@icmm.csic.e [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid (Spain); Galindo, R. Escobar [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid (Spain); Centro de Microanalisis de Materiales, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Martinez, R. [AIN, Centro de Ingenieria Avanzada de Superficies, 31191 Cordovilla, Pamplona (Spain); Sanchez, O. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid (Spain); Palacio, C. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Albella, J.M. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid (Spain)

    2011-03-31

    The development of mixed-oxide thin films allows obtaining materials with better properties than those of the different binary oxides, which makes them suitable for a great number of applications in different fields, such as tribology, optics or microelectronics. In this paper we investigate the deposition of mixed chromium and silicon oxides deposited by reactive magnetron sputtering with a view to use them as optical coatings with an adjustable refractive index. These films have been characterized by means of Rutherford backscattering spectrometry, Auger electron spectroscopy, X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy and spectroscopic ellipsometry so as to determine how the deposition conditions influence the characteristics of the material. We have found that the deposition parameter whose influence determines the properties of the films to a greater extent is the amount of oxygen in the reactive sputtering gas.

  12. Porous microspheres of manganese-cerium mixed oxides by a polyvinylpyrrolidone assisted solvothermal method

    Science.gov (United States)

    Schmit, F.; Bois, L.; Chiriac, R.; Toche, F.; Chassagneux, F.; Descorme, C.; Besson, M.; Khrouz, L.

    2017-04-01

    Mixed cerium manganese oxides were synthesized using a polyvinylpyrrolidone (PVP) assisted solvothermal method. Materials obtained after calcination at 400 °C were characterized by X-ray diffraction, scanning and transmission electron microscopies, electron paramagnetic resonance (EPR), Raman spectroscopy, thermal analysis and nitrogen adsorption/desorption isotherms. The influence of the synthesis parameters on the oxide structure, such as the Mn:Ce ratio or the amount of PVP, was discussed. Micrometric spheres of mixed Mn-Ce oxides, resulting from the aggregation of 100 nm porous snowflakes, were successfully synthesized. These snowflakes were formed from the aggregation of smaller oriented crystallites (size 4 nm). The hydrothermal stability of these materials was also investigated.

  13. Oxidative cleavage of erucic acid for the synthesis of brassylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed J. Nasrullah; Pooja Thapliyal; Erica N. Pfarr; Nicholas S. Dusek; Kristofer L. Schiele; James A. Bahr

    2010-10-29

    The main focus of this work is to synthesize Brassylic Acid (BA) using oxidative cleavage of Erucic Acid (EA). Crambe (Crambe abyssinica) is an industrial oilseed grown in North Dakota. Crambe has potential as an industrial fatty acid feedstock as a source of Erucic acid (EA). It has approximately 50-60 % of EA, a C{sub 22} monounsaturated fatty acid. Oxidative cleavage of unsaturated fatty acids derived from oilseeds produces long chain (9, 11, and 13 carbon atoms) dibasic and monobasic acids. These acids are known commercial feedstocks for the preparation of nylons, polyesters, waxes, surfactants, and perfumes. Other sources of EA are Rapeseed seed oil which 50-60 % of EA. Rapeseed is grown outside USA. The oxidative cleavage of EA was done using a high throughput parallel pressure reactor system. Kinetics of the reaction shows that BA yields reach a saturation at 12 hours. H{sub 2}WO{sub 4} was found to be the best catalyst for the oxidative cleavage of EA. High yields of BA were obtained at 80 C with bubbling of O{sub 2} or 10 bar of O{sub 2} for 12 hours.

  14. Synergy of FexCe1-xO2 mixed oxides for N2O decomposition

    NARCIS (Netherlands)

    Perez-Alonso, FJ; Melian Cabrera, Ignacio; Granados, ML; Kapteijn, F; Fierro, JLG

    2006-01-01

    Fe-Ce mixed oxides prepared by coprecipitation showed considerable synergy in N2O decomposition when compared with pure metal oxide counterparts. The mixed system also displayed higher stability in reaction at high temperature. Through characterisation by XRD, XPS and TPR, the activity-stability

  15. Synergy of FexCe1−xO2 mixed oxides for N2O decomposition

    NARCIS (Netherlands)

    Perez-Alonso, F.J.; Melián-Cabrera, I.; López Granados, M.; Kapteijn, F.; Fierro, J.L.G.

    2006-01-01

    Fe–Ce mixed oxides prepared by coprecipitation showed considerable synergy in N2O decomposition when compared with pure metal oxide counterparts. The mixed system also displayed higher stability in reaction at high temperature. Through characterisation by XRD, XPS and TPR, the activity–stability

  16. Synergy of FexCe1−xO2 mixed oxides for N2O decomposition

    NARCIS (Netherlands)

    Perez-Alonso, F.J.; Melián-Cabrera, I.; López Granados, M.; Kapteijn, F.; Fierro, J.L.G.

    2006-01-01

    Fe–Ce mixed oxides prepared by coprecipitation showed considerable synergy in N2O decomposition when compared with pure metal oxide counterparts. The mixed system also displayed higher stability in reaction at high temperature. Through characterisation by XRD, XPS and TPR, the activity–stability imp

  17. Synergy of FexCe1-xO2 mixed oxides for N2O decomposition

    NARCIS (Netherlands)

    Perez-Alonso, FJ; Melian Cabrera, Ignacio; Granados, ML; Kapteijn, F; Fierro, JLG

    2006-01-01

    Fe-Ce mixed oxides prepared by coprecipitation showed considerable synergy in N2O decomposition when compared with pure metal oxide counterparts. The mixed system also displayed higher stability in reaction at high temperature. Through characterisation by XRD, XPS and TPR, the activity-stability imp

  18. Graphene Oxide Reinforced Polylactic Acid/Polyurethane Antibacterial Composites

    OpenAIRE

    Xiaoli An; Haibin Ma; Bin Liu; Jizeng Wang

    2013-01-01

    Nanocomposites from PLA/PU containing small concentrations of graphene oxide (GO) were prepared by simple liquid-phase mixing followed by casting. The as-prepared ternary PLA/PU/GO composite films exhibited good antibacterial activity against the gram-positive Staphylococcus aureus and the gram-negative Escherichia coli, due to the excellent antibacterial property of GO sheets with high specific surface area. The addition of GO inhibited the attachment and proliferation of microbes on the fil...

  19. Direct evidence for active site-dependent formic acid electro-oxidation by topmost-surface atomic redistribution in a ternary PtPdCu electrocatalyst.

    Science.gov (United States)

    Cui, Chun-Hua; Li, Hui-Hui; Cong, Huai-Ping; Yu, Shu-Hong; Tao, Franklin Feng

    2012-12-25

    The active site-dependent electrochemical formic acid oxidation was evidenced by the increased coverage of Pt in the topmost mixed PtPd alloy layer of ternary PtPdCu upon potential cycling, which demonstrated two catalytic pathways only in one catalyst owing to surface atomic redistribution in an acidic electrolyte environment.

  20. Treatment of azo dye Acid Orange 52 using ozonation and completed-mixed activated sludge process

    Science.gov (United States)

    Abidin, C. Z. A.; Fahmi; Ong, S. A.; Ahmad, R.; Sabri, S. N.

    2017-06-01

    In this study, the characteristic of colour and COD removal of azo dye Acid Orange 52 (AO52) by ozonation, in combination with complete-mixed activated sludge process (CMAS) was evaluated. The experimentation was arranged in two phases: during the first one, only ozonation was performed, while, during the second phase, it was integrated with CMAS. The performance of colour and COD concentration of AO52 with and without CMAS treatment, is compared and evaluated. From the results, it is obvious that high decolourization from the start of CMAS was contributed from the pre-treatments. The colour removal was due to the fact that ozonation able to cleave the azo bonds that represent colour. Thus, CMAS without pre-treatment are unable to decolourize the dyes sufficiently. 59.6% COD was removed from the first-stage, while merely 9.8% COD fraction removed from the subsequence second-stage CMAS. It is suggested that the rapid COD removal without ozonation are due to activated sludge adsorption processes. The decreased of mixed liquor suspended solids (MLSS) affected the CMAS performances, as the biomass decreased due to lack of nutrient for activated sludge microorganisms to multiply. Results from pre-ozonation alone contributed more than 50% of total COD removal, which indicated that at higher ozone dosage, tend to mineralize azo dye. Thus, ozonation not oxidized the dye though complete mineralization that produce carbon dioxide and water. However, it is a potential process for enhancing colour removal and biodegradability of dye-containing wastewater, once the appropriate ozonation time is determined. Therefore, the role of ozonation seems to break down the dye molecules and created ozonation by-product that is easily biodegraded in the subsequent biological treatment.

  1. Human placenta metabolizes fatty acids: implications for fetal fatty acid oxidation disorders and maternal liver diseases.

    Science.gov (United States)

    Shekhawat, Prem; Bennett, Michael J; Sadovsky, Yoel; Nelson, D Michael; Rakheja, Dinesh; Strauss, Arnold W

    2003-06-01

    The role of fat metabolism during human pregnancy and in placental growth and function is poorly understood. Mitochondrial fatty acid oxidation disorders in an affected fetus are associated with maternal diseases of pregnancy, including preeclampsia, acute fatty liver of pregnancy, and the hemolysis, elevated liver enzymes, and low platelets syndrome called HELLP. We have investigated the developmental expression and activity of six fatty acid beta-oxidation enzymes at various gestational-age human placentas. Placental specimens exhibited abundant expression of all six enzymes, as assessed by immunohistochemical and immunoblot analyses, with greater staining in syncytiotrophoblasts compared with other placental cell types. beta-Oxidation enzyme activities in placental tissues were higher early in gestation and lower near term. Trophoblast cells in culture oxidized tritium-labeled palmitate and myristate in substantial amounts, indicating that the human placenta utilizes fatty acids as a significant metabolic fuel. Thus human placenta derives energy from fatty acid oxidation, providing a potential explanation for the association of fetal fatty acid oxidation disorders with maternal liver diseases in pregnancy.

  2. Lewis acidity enhancement of triarylborane by appended phosphine oxide groups.

    Science.gov (United States)

    Kwak, Jaewoo; Nghia, Nguyen Van; Lee, Junseong; Kim, Hyoseok; Park, Myung Hwan; Lee, Min Hyung

    2015-03-14

    A series of mono-, di-, and tri-phosphine oxide substituted triarylboranes, Mes2BAr (1), MesBAr2 (2), and BAr3 (3) (Ar = 4-(Ph2PO)-2,6-Me2-C6H2) were prepared to investigate the effect of a phosphine oxide group (Ph2PO) on Lewis acidity enhancement of triarylboranes. The X-ray crystal structure of 3 revealed peripheral decoration of Ph2PO groups with a C3-axis perpendicular to the trigonal boron center. UV/Vis absorption and PL spectra indicated a significant contribution of π(Mes or phenylene) → pπ(B) charge transfer in the lower-energy electronic transition. The reduction potential measured by cyclic voltammetry showed apparent LUMO stabilization by introduction of phosphine oxide groups, the extent of which gradually increased with the increasing number of phosphine oxide groups. Lewis acidity enhancement was also supported by the gradual increase in fluoride ion affinity in the order 3 > 2 > 1. Theoretical calculations suggest that introduction of a Ph2PO group into a triarylborane significantly enhances the Lewis acidity of the boron center via an inductive electron-withdrawing effect and this effect is additive for multiple phosphine oxide groups.

  3. Quantitative analysis of mixed hydrofluoric and nitric acids using Raman spectroscopy with partial least squares regression.

    Science.gov (United States)

    Kang, Gumin; Lee, Kwangchil; Park, Haesung; Lee, Jinho; Jung, Youngjean; Kim, Kyoungsik; Son, Boongho; Park, Hyoungkuk

    2010-06-15

    Mixed hydrofluoric and nitric acids are widely used as a good etchant for the pickling process of stainless steels. The cost reduction and the procedure optimization in the manufacturing process can be facilitated by optically detecting the concentration of the mixed acids. In this work, we developed a novel method which allows us to obtain the concentrations of hydrofluoric acid (HF) and nitric acid (HNO(3)) mixture samples with high accuracy. The experiments were carried out for the mixed acids which consist of the HF (0.5-3wt%) and the HNO(3) (2-12wt%) at room temperature. Fourier Transform Raman spectroscopy has been utilized to measure the concentration of the mixed acids HF and HNO(3), because the mixture sample has several strong Raman bands caused by the vibrational mode of each acid in this spectrum. The calibration of spectral data has been performed using the partial least squares regression method which is ideal for local range data treatment. Several figures of merit (FOM) were calculated using the concept of net analyte signal (NAS) to evaluate performance of our methodology.

  4. Assays for urinary biomarkers of oxidatively damaged nucleic acids

    DEFF Research Database (Denmark)

    Weimann, Allan; Broedbaek, Kasper; Henriksen, Trine;

    2012-01-01

    and skills requirement. The available ELISA methods present considerable specificity problems and cannot be recommended at present. The oxidized nucleic acid metabolites in urine are assumed to originate from the DNA and RNA. However, direct evidence is not available. A possible contribution from...

  5. Chloramines and hypochlorous acid oxidize erythrocyte peroxiredoxin 2.

    Science.gov (United States)

    Stacey, Melissa M; Peskin, Alexander V; Vissers, Margreet C; Winterbourn, Christine C

    2009-11-15

    Peroxiredoxin 2 (Prx2) is an abundant thiol protein that is readily oxidized in erythrocytes exposed to hydrogen peroxide. We investigated its reactivity in human erythrocytes with hypochlorous acid (HOCl) and chloramines, relevant oxidants in inflammation. Prx2 was oxidized to a disulfide-linked dimer by HOCl, glycine chloramine (GlyCl), and monochloramine (NH(2)Cl) in a dose-dependent manner. In the absence of added glucose, Prx2 and GSH showed similar sensitivities. Second-order rate constants for the reactions of Prx2 with NH(2)Cl and GlyCl were 1.5 x 10(4) and 8 M(-1) s(-1), respectively. The NH(2)Cl value is approximately 10 times higher than that for GSH, whereas Prx2 is approximately 30 times less sensitive than GSH to GlyCl. Thus, the relative sensitivity of Prx2 to GlyCl is greater in the erythrocyte. Oxidation of erythrocyte Prx2 and GSH was less in the presence of glucose, probably because of recycling. High doses of NH(2)Cl resulted in incomplete regeneration of reduced Prx2, suggesting impairment of the recycling mechanism. Our results show that, although HOCl and chloramines are less selective than H(2)O(2), they nevertheless oxidize Prx2. Exposure to these inflammatory oxidants will result in Prx2 oxidation and could compromise the erythrocyte's ability to resist damaging oxidative insult.

  6. Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

    2001-01-01

    oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced......The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...

  7. Determination of mechanism for soot oxidation with NO on potassium supported Mg-Al hydrotalcite mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Su, Q.; Gao, X. [Institute of Internal Combustion Engine, Dalian University of Technology, Dalian (China); Li, Q.; Wang, Z.; Zhang, Z. [School of Chemistry and Chemical Engineering, University of Jinan, Jinan (China)

    2011-11-15

    Soot oxidation with NO (in the absence of gas phase O{sub 2}) on potassium-supported Mg-Al hydrotalcite mixed oxides (K/MgAlO) was studied using a temperature-programmed reaction and in situ FTIR techniques. Nitrite and the ketene group were identified as the reaction intermediates and thus a nitrite-ketene mechanism was proposed in which surface active oxygen on K sites of K/MgAlO is transferred to soot by NO through nitrites. In the absence of gas phase O{sub 2}, soot oxidation with NO at lower temperatures (below 450 C) is limited by the amount of active oxygen on the K sites. This kind of active oxygen is not reusable but can be replenished in the presence of gas phase O{sub 2}. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. The electrochemical polishing behavior of the Inconel 718 alloy in perchloric-acetic mixed acids

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.A. [Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan (China)], E-mail: gfehu@mail.cgu.edu.tw; Chen, Y.C.; Chang, J.H. [Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan (China)

    2008-02-15

    The electropolishing behavior of the Inconel 718 alloy was studied by using rotating disc electrode (RDE) in the HClO{sub 4}-CH{sub 3}COOH mixed acids with different HClO{sub 4}-concentrations. After electropolishing, surface morphologies of RDE specimens were examined with surface profiler, atomic force microscope and scanning electron microscope. According to the surface morphologies observed, three types of anodic dissolution behavior can be characterized in relation to the HClO{sub 4}-content in mixed acids; namely, leveling without brightening of the surface in the mixed acids with 10 and 20 vol% HClO{sub 4}, leveling and brightening of the surface in the mixed acids with 30 and 40 vol% HClO{sub 4}, and a matt and gray surface in the mixed acids with 50 vol% or more HClO{sub 4}. Anodic dissolution in the first and second dissolution types follows a mass-transfer controlled mechanism, in which a linear relationship between the reciprocal of limiting-current density and the reciprocal of square root of rotating speed of RDE specimen can be detected. Owing to precipitation of salt film on the polished surface of the Inconel 718 material, saturated dissolved metallic ions could be the chemical species for the mass-controlled mechanism. The salt film, in addition, could enhance the corrosion resistance of the Inconel 718 alloy.

  9. Implications of impaired ketogenesis in fatty acid oxidation disorders.

    Science.gov (United States)

    Olpin, Simon Edward

    2004-03-01

    Long-chain fatty acids are important sources of respiratory fuel for many tissues and during fasting the rate of hepatic production of ketone bodies is markedly increased. Many extra hepatic tissues utilize ketone bodies in the fasted state with the advantage that glucose is "spared" for more vital tissues like the brain. This glucose sparing effect of ketones is especially important in infants where there is a high proportional glucose utilization in cerebral tissue. The first reported inherited defect affecting fatty acid oxidation was described in 1973 and to date about 15 separate disorders have been described. Although individually rare, cumulatively fatty acid oxidation defects are relatively common, have major consequences for affected individuals and their families, and carry significant health care implications. The major biochemical consequence of fatty acid oxidation defects is an inability of extra hepatic tissues to utilize fatty acids as an energy source with absent or limited hepatic capacity to generate ketones. Clinically patients usually present in infancy with acute life-threatening hypoketotic hypoglycaemia, liver disease, hyperammonaemia and cerebral oedema, with or without cardiac involvement, usually following a period of catabolic stress. Chronically there may be muscle involvement with hypotonia or exercise intolerance with or without cardiomyopathy. Treatment is generally by the avoidance of fasting, frequent carbohydrate rich feeds and for long-chain defects, the replacement of long-chain dietary fats with medium-chain formulae. Novel approaches to treatment include the use of d,l-3-hydoxybutyrate or heptanoate as an alternative energy source.

  10. Ab initio and kinetic modeling studies of formic acid oxidation

    DEFF Research Database (Denmark)

    Marshall, Paul; Glarborg, Peter

    2015-01-01

    A detailed chemical kinetic model for oxidation of formic acid (HOCHO) in flames has been developed, based on theoretical work and data from literature. Ab initio calculations were used to obtain rate coefficients for reactions of HOCHO with H, O, and HO2. Modeling predictions with the mechanism...... as the fate of HOCO, determines the oxidation rate of formic acid. At lower temperatures HO2, formed from HOCO + O2, is an important chain carrier and modeling predictions become sensitive to the HOCHO + HO2 reaction. © 2014 The Combustion Institute....... on calculations with the kinetic model. Formic acid is consumed mainly by reaction with OH, yielding OCHO, which dissociates rapidly to CO2 + H, and HOCO, which may dissociate to CO + OH or CO2 + H, or react with H, OH, or O2 to form more stable products. The branching fraction of the HOCHO + OH reaction, as well...

  11. Oxidative dehydrogenation of isobutane over supported V–Mo mixed oxides

    Directory of Open Access Journals (Sweden)

    IOAN-CEZAR MARCU

    2010-08-01

    Full Text Available Vanadium–molybdenum oxides supported on Al2O3, CeO2 and TiO2 were prepared by a “wet” impregnation method, characterized using XRD, N2 adsorption, UV–Vis spectroscopy, electrical conductivity measurements and tested in the oxidative dehydrogenation of isobutane. The catalytic performance in the oxidative dehydrogenation of isobutane at 400–550 °C depended on the nature of support and on the content of VMoO species on the support. The catalysts supported on alumina were more active and selective than those supported on ceria and titania.

  12. Selective oxidation of benzene and cyclohexane using amorphous microporous mixed oxides; Selektive Oxidation von Benzol und Cyclohexan mit amorphen mikroporoesen Mischoxiden

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckmann, M.

    2000-07-01

    Phenol was to be produced by direct oxidation of benzene with environment-friendly oxidants like hydrogen peroxide, oxygen, or ozone. Catalysts were amorphous microporous mixed oxides whose properties can be selected directly in the sol-gel synthesis process. Apart from benzene, also cyclohexane was oxidized with ozone using AMM catalysts in order to get more information on the potential of ozone as oxidant in heterogeneously catalyzed reactions. [German] Ziel dieser Arbeit war die Herstellung von Phenol durch die Direktoxidation von Benzol mit umweltfreundlichen Oxidationsmitteln wie Wasserstoffperoxid, Sauerstoff oder Ozon. Als Katalysatoren dienten amorphe mikroporoese Mischoxide, da deren Eigenschaften direkt in der Synthese durch den Sol-Gel-Prozess gezielt eingestellt werden koennen. Neben Benzol wurde auch Cyclohexan mit Ozon unter der Verwendung von AMM-Katalysatoren oxidiert, um das Potential von Ozon als Oxiationsmittel in heterogen katalysierten Reaktionen naeher zu untersuchen. (orig.)

  13. Soft chemical control of the crystal and magnetic structure of a layered mixed valent manganite oxide sulfide

    Directory of Open Access Journals (Sweden)

    Jack N. Blandy

    2015-04-01

    Full Text Available Oxidative deintercalation of copper ions from the sulfide layers of the layered mixed-valent manganite oxide sulfide Sr2MnO2Cu1.5S2 results in control of the copper-vacancy modulated superstructure and the ordered arrangement of magnetic moments carried by the manganese ions. This soft chemistry enables control of the structures and properties of these complex materials which complement mixed-valent perovskite and perovskite-related transition metal oxides.

  14. Pd oxides/hydrous oxides as highly efficient catalyst for formic acid electrooxidation

    Science.gov (United States)

    Yan, Liang; Yao, Shikui; Chang, Jinfa; Liu, Changpeng; Xing, Wei

    2014-03-01

    A novel Pd-based catalyst for formic acid electrooxidation (FAEO) was prepared by annealing commercial Pd/C catalyst under the O2 atmosphere at 100 °C, which exhibits excellent catalytic activity and stability for FAEO due to introduction of Pd oxides/hydrous oxides (POHOs). The catalytic activity of the as-prepared catalyst towards FAEO is 1.86 times of the commercial Pd/C catalyst in 0.5 M H2SO4 + 0.5 M HCOOH solution. Chronoamperometric curves show obvious improvement of the as-prepared catalyst electrocatalytic stability for FAEO. It is confirmed that POHOs can provide the required oxygen species for intermediate CO oxidation during the oxidation process of formic acid.

  15. Hybrid Co-deposition of Mixed-Valent Molybdenum-Germanium Oxides (MoxGeyOz): A Route to Tunable Optical Transmission (Postprint)

    Science.gov (United States)

    2015-08-05

    ultraviolet– visible -near-infrared optical spectrophotometry ( UV –Vis–NIR). Structural properties of the as-deposited MoxGeyOz films, including roughness...photoelectron spectroscopy . 15. SUBJECT TERMS Magnetron sputtering, Ellipsometry, X-ray photoelectron spectroscopy , Mixed oxides, Germanium oxide...photoelectron spectroscopy Mixed oxides Germanium oxide Molybdenum oxide Thin film Optical characterizationMixed-valent oxides of molybdenum and germanium

  16. Degradation of organophosphorus pesticide parathion methyl on nanostructured titania-iron mixed oxides

    Science.gov (United States)

    Henych, Jiří; Štengl, Václav; Slušná, Michaela; Matys Grygar, Tomáš; Janoš, Pavel; Kuráň, Pavel; Štastný, Martin

    2015-07-01

    Titania-iron mixed oxides with various Ti:Fe ratio were prepared by homogeneous hydrolysis of aqueous solutions of titanium(IV) oxysulphate and iron(III) sulphate with urea as a precipitating agent. The synthesized samples were characterized by X-ray diffraction, Raman and infrared spectroscopy, scanning and transmission electron microscopy, XRF analysis, specific surface area (BET) and porosity determination (BJH). These oxides were used for degradation of organophosporus pesticide parathion methyl. The highest degradation efficiency approaching degraded on the surfaces of pure oxides. In general, the highest degradation rate exhibited samples consisted of the iron or titanium oxide containing a moderate amount of the admixture. However, distinct correlations between the degradation rate and the sorbent composition were not identified.

  17. Surface oxide growth on platinum electrode in aqueous trifluoromethanesulfonic acid

    Science.gov (United States)

    Furuya, Yoshihisa; Mashio, Tetsuya; Ohma, Atsushi; Dale, Nilesh; Oshihara, Kenzo; Jerkiewicz, Gregory

    2014-10-01

    Platinum in the form of nanoparticles is the key and most expensive component of polymer electrolyte membrane fuel cells, while trifluoromethanesulfonic acid (CF3SO3H) is the smallest fluorinated sulfonic acid. Nafion, which acts as both electrolyte and separator in fuel cells, contains -CF2SO3H groups. Consequently, research on the electrochemical behaviour of Pt in aqueous CF3SO3H solutions creates important background knowledge that can benefit fuel cell development. In this contribution, Pt electro-oxidation is studied in 0.1 M aqueous CF3SO3H as a function of the polarization potential (Ep, 1.10 ≤ Ep ≤ 1.50 V), polarization time (tp, 100 ≤ tp ≤ 104 s), and temperature (T, 278 ≤ T ≤ 333 K). The critical thicknesses (X1), which determines the applicability of oxide growth theories, is determined and related to the oxide thickness (dox). Because X1 > dox for the entire range of Ep, tp, and T values, the formation of Pt surface oxide follows the interfacial place-exchange or the metal cation escape mechanism. The mechanism of Pt electro-oxidation is revised and expanded by taking into account possible interactions of cations, anions, and water molecules with Pt. A modified kinetic equation for the interfacial place exchange is proposed. The application of the interfacial place-exchange and metal cation escape mechanisms leads to an estimation of the Ptδ+-Oδ- surface dipole (μPtO), and the potential drop (Vox) and electric field (Eox) within the oxide. The Pt-anion interactions affect the oxidation kinetics by indirectly influencing the electric field within the double layer and the surface oxide.

  18. Selection of mixed conducting oxides for oxidative dehydrogenation of propane with pulse experiments

    NARCIS (Netherlands)

    Crapanzano, Salvatore; Babich, Igor V.; Lefferts, Leon

    2011-01-01

    In this study, propane pulse experiments at 550 °C are used as a method to select suitable oxides for further operation of catalytic dense membrane reactor (CDMR) for oxidative dehydrogenation of propane. Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF), La2NiO4+δ (LN) and PrBaCo2O5+δ (PBC) powders were used as mode

  19. Canopy leaching of subtropical mixed forests under acid rain

    Institute of Scientific and Technical Information of China (English)

    Renjun XIANG; Liyuan CHAI; Xilin ZHANG; Gong ZHANG; Guifang ZHAO

    2008-01-01

    Leaching of major ions from acid precipitation in a subtropical forest was examined based on an experi-ment in four sample sites in Shaoshan City, Hunan Province, China, from January 2001 to June 2002. Results clearly show that when rain passed through the canopy, pH increased and the evidence of ion uptake was presented for SO42- , NO3-, Mg2+ and NH4+ ions, espe-cially of NH4+ and NO3-. The percentages of dissolved SO42-, Ca2+ and Mg2+ show a decreasing trend with increasing rainfall. Percentages of leaching Ca2+, K+ and Cl- ions show an increasing trend as a function of increased pH values. The forest canopy in Shaoshan City has a strong effect on the uptake of SO42- and NO3- ions under acid rain conditions. The decreasing order of ions leaching in the forest canopy is as follows: K+> Ca2+ > Cl- > Mg2+ > SO42- > NO3- > NH4+ > Na+.

  20. Biohydrogenation of unsaturated fatty acids by a mixed culture of rumen microorganisms.

    Science.gov (United States)

    Kellens, M J; Goderis, H L; Tobback, P P

    1986-08-01

    The biohydrogenation of C-18 unsaturated fatty acids was examined in a mixed culture of microorganisms prepared by inoculating a proper growth medium with a sample of rumen fluid. Some major factors influencing the hydrogenation capacity have been investigated. The age of the mixed culture, the type of inoculum used, the concentration of substrates as well as the presence of sterile rumen fluid in the growth medium were found to be important factors determining biohydrogenation behavior. It could be shown that the mixed microbial culture, which had been grown for about 24 h on a medium similar to that of Bryant and Robinson, contained sterile rumen fluid (10% v/v), and had been inoculated with a sample of the whole untreated rumen content, had the best biohydrogenation capacity. The culture was able to carry out the complete conversion of linoleic and linolenic acid to stearic acid.

  1. Lactic acid production from corn stover using mixed cultures of Lactobacillus rhamnosus and Lactobacillus brevis.

    Science.gov (United States)

    Cui, Fengjie; Li, Yebo; Wan, Caixia

    2011-01-01

    Mixed cultures of Lactobacillus rhamnosus and Lactobacillus brevis was studied for improving utilization of both cellulose- and hemicellulose-derived sugars from corn stover for lactic acid production. During simultaneous saccharification and fermentation (SSF) of NaOH-treated corn stover by the mixed cultures, a lactic acid yield of 0.70 g/g was obtained, which was about 18.6% and 29.6% higher than that by single cultures of L. rhamnosus and L. brevis, respectively. Our results indicated that lactic acid yield from NaOH-pretreated corn stover by mixed cultures of L. rhamnosus and L. brevis was comparable to that from pure sugar mixtures (0.73 g/g of glucose/xylose mixture at 3:1 w/w). Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Effect of sulfonylureas on hepatic fatty acid oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Patel, T.B.

    1986-08-01

    In isolated rat livers perfused with oleic acid (0.1 mM), infusion of tolbutamide or glyburide decreased the rate of ketogenesis in a dose-dependent manner. The inhibition of fatty acid oxidation was maximal at 2.0 mM and 10 M concentrations of tolbutamide and glyburide, respectively. Neither tolbutamide nor glyburide inhibited ketogenesis in livers perfused with octanoate. The inhibition of hepatic ketogenesis by sulfonylureas was independent of perfusate oleic acid concentration. Additionally, in rat livers perfused with oleic acid in the presence of L-(-)-carnitine (10 mM), submaximal concentrations of tolbutamide and glyburide did not inhibit hepatic ketogenesis. Finally, glyburide infusion into livers perfused with (U- $C)oleic acid (0.1 mM) increased the rate of UC label incorporation into hepatic triglycerides by 2.5-fold. These data suggest that both tolbutamide and glyburide inhibit long-chain fatty acid oxidation by inhibition the key regulatory enzyme, carnitine palmitoyltransferase I, most probably by competing with L-(-)-carnitine.

  3. Ascorbate and dehydroascorbic acid as reliable biomarkers of oxidative stress

    DEFF Research Database (Denmark)

    Lykkesfeldt, Jens

    2007-01-01

    Lack of post-sampling stability of ascorbate and dehydroascorbic acid and failure to block their in vivo equilibrium have lowered their value as biomarkers of oxidative stress and limited the ability to further investigate their possible role in disease prevention. In the present paper, the analy......Lack of post-sampling stability of ascorbate and dehydroascorbic acid and failure to block their in vivo equilibrium have lowered their value as biomarkers of oxidative stress and limited the ability to further investigate their possible role in disease prevention. In the present paper......, the analytical reproducibility was tested by repeated analysis of plasma aliquots from one individual over four years. The plasma was subjected to acidic deproteinization with an equal volume of 10% meta-phosphoric acid containing 2 mM EDTA and analyzed for ascorbate and dehydroascorbic acid by high......-performance liquid chromatography with coulometric detection. In a parallel experiment, stability of human plasma samples treated as above and stored at -80°C for five years was tested in a cohort of 131 individuals. No degradation or shift in the equilibrium between ascorbate and dehydroascorbic acid was observed...

  4. Electrochemical degradation of clofibric acid in water by anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sires, Ignasi [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Cabot, Pere Lluis [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Centellas, Francesc [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Garrido, Jose Antonio [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Rodriguez, Rosa Maria [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Arias, Conchita [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Brillas, Enric [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)]. E-mail: brillas@ub.edu

    2006-10-05

    Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical ({center_dot}OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl{sub 2}. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with {center_dot}OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO{sub 2} with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.

  5. Hepatic Fatty Acid Oxidation Restrains Systemic Catabolism during Starvation

    Directory of Open Access Journals (Sweden)

    Jieun Lee

    2016-06-01

    Full Text Available The liver is critical for maintaining systemic energy balance during starvation. To understand the role of hepatic fatty acid β-oxidation on this process, we generated mice with a liver-specific knockout of carnitine palmitoyltransferase 2 (Cpt2L−/−, an obligate step in mitochondrial long-chain fatty acid β-oxidation. Fasting induced hepatic steatosis and serum dyslipidemia with an absence of circulating ketones, while blood glucose remained normal. Systemic energy homeostasis was largely maintained in fasting Cpt2L−/− mice by adaptations in hepatic and systemic oxidative gene expression mediated in part by Pparα target genes including procatabolic hepatokines Fgf21, Gdf15, and Igfbp1. Feeding a ketogenic diet to Cpt2L−/− mice resulted in severe hepatomegaly, liver damage, and death with a complete absence of adipose triglyceride stores. These data show that hepatic fatty acid oxidation is not required for survival during acute food deprivation but essential for constraining adipocyte lipolysis and regulating systemic catabolism when glucose is limiting.

  6. The inborn errors of mitochondrial fatty acid oxidation.

    Science.gov (United States)

    Vianey-Liaud, C; Divry, P; Gregersen, N; Mathieu, M

    1987-01-01

    To date, seven inborn errors of mitochondrial fatty acid oxidation have been identified. A total of about 100 patients in the world have been reported. Clinically the beta-oxidation defects are more often characterized by episodic hypoglycaemia leading to a coma mimicking Reye's syndrome. The hypoglycaemia is non-ketotic since the synthesis of ketone bodies is deficient. Periods of decompensation occur when carbohydrate supply is poor, e.g. prolonged fasting, vomiting, or increased caloric requirements, as and when lipid stores are used. Defects in beta-oxidation have also been reported to be one cause of sudden infant death syndrome. The diagnosis of these inborn errors is by biochemical investigation since where symptoms suggest such a defect, the precise aetiology cannot be assessed. The biochemical diagnosis is based firstly on identification of abnormal plasma and of urinary metabolites during acute attacks. Derivatives of the omega-oxidation and omega-1-oxidation of medium chain fatty acids have been identified, as well as acylglycine and acylcarnitine conjugates. These metabolites are nearly always absent when patients are in good clinical condition. Secondly, the diagnosis must be based on the identification of the enzymatic defects: this involves global assays which allow a localization of the 'level' of the defect (i.e. the oxidation of long, medium or short chain fatty acids) and specific measurement of enzyme activities (acyl-CoA dehydrogenases and electron carriers: ETF and ETF-DH). The diagnosis of these disorders is of prime importance because of the severity of the clinical symptoms. These can be prevented, in some cases, by an appropriate diet (a high carbohydrate, low fat diet, sometimes supplemented with L-carnitine). In other cases, genetic counselling can be offered.

  7. α-Tocopherol/Gallic Acid Cooperation in the Protection of Galactolipids Against Ozone-Induced Oxidation.

    Science.gov (United States)

    Rudolphi-Skórska, Elżbieta; Filek, Maria; Zembala, Maria

    2016-04-01

    The protective ability of α-tocopherol (TOH) and gallic acid (GA) acting simultaneously at the moment of oxidizer application was evaluated by determination of galactolipid layers' oxidation degree. Addition of GA resulted in a significant decrease of ozone-derived radicals shifting the threshold of lipid sensitivity by an amount approximately corresponding to the GA intake in bulk reaction with ozone. TOH presence in lipid layers results in a change of the role of GA which additionally may be involved in the reduction of tocopheroxyl radical formed during oxidation. This leads to a decrease in effectiveness of GA in diminishing the amount of ozone radicals. Such an effect was not observed for mixed layers containing galactolipid and pre-oxidized tocopherol where the ozone threshold level was associated with a stoichiometry of GA + O3 reaction. It was concluded that probably subsequent transformations of tocopheroxyl radical to less reactive forms prevent its reaction with GA the entire quantity of which is used for radicals scavenging. This result shows the role of time parameter in systems where substrates are engaged in various reactions taking place simultaneously. The inactivation of 1,1-diphenyl-2-picrylhydrazyl radical by studied antioxidants in homogeneous system confirmed observations made on the basis of lipid layer properties indicating their antagonistic action (at least at studied conditions). Formation of layers in post-oxidation situation did not depend whether tocopherol was oxidized during oxidation of lipid/tocopherol mixture or was introduced as pre-oxidized. This may be interpreted as indication that products of tocopherol oxidation may stabilize lipid layers.

  8. Formic acid oxidation at platinum-bismuth catalysts

    Directory of Open Access Journals (Sweden)

    Popović Ksenija Đ.

    2015-01-01

    Full Text Available The field of heterogeneous catalysis, specifically catalysis on bimetallic surfaces, has seen many advances over the past few decades. Bimetallic catalysts, which often show electronic and chemical properties that are distinct from those of their parent metals, offer the opportunity to obtain new catalysts with enhanced selectivity, activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance for fuel cell applications. Platinum is one of the most commonly used catalysts for this reaction, despite the fact that it shows a few significant disadvantages: high cost and extreme susceptibility to poisoning by CO. To solve this problem, several approaches have been used, but generally, they all consist in the modification of platinum with a second element. Especially, bismuth has received significant attention as Pt modifier. According to the results presented in this survey dealing with the effects influencing the formic acid oxidation it was found that two types of Pt-Bi bimetallic catalysts (bulk and low loading deposits on GC showed superior catalytic activity in terms of the lower onset potential and oxidation current density, as well as exceptional stability compared to Pt. The findings in this report are important for the understanding of mechanism of formic acid electrooxidation on a bulk alloy and decorated surface, for the development of advanced anode catalysts for direct formic acid fuel cells, as well as for the synthesis of novel low-loading bimetallic catalysts. The use of bimetallic compounds as the anode catalysts is an effective solution to overcoming the problems of the formic acid oxidation current stability for long term applications. In the future, the tolerance of both CO poisoning and electrochemical leaching should be considered as the key factors in the development

  9. Bi–Mn mixed metal organic oxide: A novel 3d-6p mixed metal coordination network

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Fa-Nian, E-mail: fshi@ua.pt [School of Science, Shenyang University of Technology, 110870 Shenyang (China); Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Rosa Silva, Ana [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Bian, Liang [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China)

    2015-05-15

    A new terminology of metal organic oxide (MOO) was given a definition as a type of coordination polymers which possess the feature of inorganic connectivity between metals and the direct bonded atoms and show 1D, 2D or 3D inorganic sub-networks. One such compound was shown as an example. A 3d-6p (Mn–Bi. Named MOOMnBi) mixed metals coordination network has been synthesized via hydrothermal method. The new compound with the molecular formula of [MnBi{sub 2}O(1,3,5-BTC){sub 2}]{sub n} (1,3,5-BTC stands for benzene-1,3,5-tricarboxylate) was characterized via single crystal X-ray diffraction technique that revealed a very interesting 3-dimensional (3D) framework with Bi{sub 4}O{sub 2}(COO){sub 12} clusters which are further connected to Mn(COO){sub 6} fragments into a 2D MOO. The topology study indicates an unprecedented topological type with the net point group of (4{sup 13}.6{sup 2})(4{sup 13}.6{sup 8})(4{sup 16}.6{sup 5})(4{sup 18}.6{sup 10})(4{sup 22}.6{sup 14})(4{sup 3}) corresponding to 3,6,7,7,8,9-c hexa-nodal net. MOOMnBi shows catalytic activity in the synthesis of (E)-α,β-unsaturated ketones. - Graphical abstract: This metal organic framework (MOF) is the essence of a 2D metal organic oxide (MOO). - Highlights: • New concept of metal organic oxide (MOO) was defined and made difference from metal organic framework. • New MOO of MOOMnBi was synthesized by hydrothermal method. • Crystal structure of MOOMnBi was determined by single crystal X-ray analysis. • The catalytic activity of MOOMnBi was studied showing reusable after 2 cycles.

  10. Oxidation kinetic analysis of a mixed uranium dicarbide and graphite compound

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, M., E-mail: mickael.marchand@cea.fr [Commissariat à l’Energie Atomique et aux énergies alternatives, CEA, CADARACHE, DEN, DEC, SPUA/Laboratoire des Combustibles Uranium, 13108 Saint Paul-lez-Durance Cedex (France); Fiquet, O., E-mail: olivier.fiquet@cea.fr [Commissariat à l’Energie Atomique et aux énergies alternatives, CEA, CADARACHE, DEN, DEC, SPUA/Laboratoire des Combustibles Uranium, 13108 Saint Paul-lez-Durance Cedex (France); Brothier, M. [Commissariat à l’Energie Atomique et aux énergies alternatives, CEA, CADARACHE, DEN, DEC, SPUA/Laboratoire des Combustibles Uranium, 13108 Saint Paul-lez-Durance Cedex (France)

    2013-06-15

    Highlights: ► Experimental study of uranium carbides and graphite powder oxidations. ► Single rate limiting step identification by extensive kinetic analysis. ► Pseudo-steady-state validation during chemical conversion. ► Combination of TGA, TDA, XRD and gas phase chromatography results. -- Abstract: The oxidation of a mixed uranium dicarbide and graphite powder has been investigated by simultaneous thermal gravimetric (TGA) and differential thermal (DTA) analyses coupled with gas phase chromatography. For isothermal oxidation conditions with temperatures below 330 °C, only the UC{sub 2} chemical phase is progressively oxidised into U{sub 3}O{sub 8} oxides. Parabolic weight gain curves as a function of oxidation over time were obtained. A detailed kinetic study is proposed to establish a pseudo-steady-state during the oxidation process. Using an experimental method based on the sudden temperature increases, a single rate-limiting step has been validated and then modelled by a 3D diffusion law. An apparent activation energy calculated from the Arrhenius representation has been evaluated at −35 kJ/mol, thus describing the diffusion of oxygen through the oxide layer.

  11. Significant enhancement of formic acid oxidation using rhodium nanostructures.

    Science.gov (United States)

    Balan, Beena K; Sathe, Bhaskar R

    2012-12-01

    The electrocatalytic activity of as-synthesized shape selective Rh nanostructures has been demonstrated using cyclic voltammetry, revealing unique shape-dependant performance towards HCOOH oxidation. Interestingly, the enhancement factor (R) for different shapes of Rh with respect to that of commercial Rh towards formic acid oxidation ranges up to 20,000% for cubes as compared to 17,500% for pyramids and 11,000% for hexagons respectively. Mechanistic pathway for comparatively better sensitivity of cubes as compared to other shapes has been correlated with the results of X-ray diffraction.

  12. Efficiency of mitochondrially targeted gallic acid in reducing brain mitochondrial oxidative damage.

    Science.gov (United States)

    Parihar, P; Jat, D; Ghafourifar, P; Parihar, M S

    2014-07-03

    Oxidative stress is associated with mitochondrial impairments. Supplying mitochondria with potent antioxidants can reduce oxidative stress—induced mitochondrial impairment. Gallic acid can be used to reduce oxidative burden in mitochondria. In order to increase the bioavailability of gallic acid inside the mitochondria we synthesized mitochondrially targeted gallic acid and explored its preventive effects against sodium nitroprusside induced oxidative stress in isolated mitochondria. Our observations revealed an increase in oxidative stress,decrease in reduced glutathione in mitochondria and increase in the mitochondrial permeability pore transition due to sodium nitroprusside treatment. Pre—treatment of gallic acid and mitochondrially targeted gallic acid to sodium nitroprusside treated mitochondria not only significantly reduced the oxidative stress but also prevented mitochondrial permeability pore transition to a significant difference. Mitochondrially targeted gallic acid was found more effective in reducing oxidative stress and mitochondrial permeability pore transition than gallic acid. We conclude that mitochondrially targeted gallic acid can be used for preventing mitochondrial impairment caused by oxidative stress.

  13. Oxidative stability of Liposomes composed of docosahexaenoic acid-containing phospholipids

    DEFF Research Database (Denmark)

    Vikbjerg, Anders Falk; Andresen, Thomas Lars; Jørgensen, Kent

    2007-01-01

    Oxidative stability of liposomes made of (Docosahexaenoic acid) DHA-containing phosphatidylcholine (PC) was examined during preparation and storage. After preparation of the liposomes, the concentration of primary (conjugated dienes) and secondary oxidation products (Thiobarbituric acid...

  14. Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template.The effects of amount of template,pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated.The final products were characterized by XRD,TEM,FT-IR,and BET.The results indicate that all the cerium-zirconium mixed oxides present a meso-structure.At molar ratio of n(CTAB)/n((Ce)+(Zr))=0.15,pH value of 9,and hydrothermal temperature of 120 ℃,the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

  15. Sol-gel synthesis and characterization of mesoporous iron-titanium mixed oxide for catalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Parida, K.M., E-mail: paridakulamani@yahoo.com [Colloids and Materials Chemistry Department, Institute of Minerals and Materials Technology, Bhubaneswar 751013, Orissa (India); Pradhan, Gajendra Kumar [Colloids and Materials Chemistry Department, Institute of Minerals and Materials Technology, Bhubaneswar 751013, Orissa (India)

    2010-10-01

    A mixed phase of mesoporous iron-titanium mixed oxide (ITMO) has been successfully synthesized by simple sol-gel technique by taking iron (II) sulphate and Ti-isopropoxide as the precursors and sodium dodecyl sulphate (SDS) as the surfactant. The prepared catalysts were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), diffuse reflectance UV-vis spectra (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic absorption spectroscopy (AAS), N{sub 2} adsorption-desorptions isotherm, temperature programmed desorption (TPD) and gas chromatography (GC). Low-angle XRD (LAXRD) as well as surface area analysis confirms the mesoporosity nature of the catalysts. The phase and crystallinity were revealed by XRD study. The crystallinity of the catalysts increased with increase in calcinations temperature. Catalysts screening were performed for oxidation of cyclohexane to cyclohexanol and cyclohexanone.

  16. Direct electrochemical production of Ti-10W alloys from mixed oxide preform precursors

    Energy Technology Data Exchange (ETDEWEB)

    Dring, K. [Imperial College London, Department of Materials, London SW7 2AZ (United Kingdom)]. E-mail: kevin.dring@imperial.ac.uk; Bhagat, R. [Imperial College London, Department of Materials, London SW7 2AZ (United Kingdom); Jackson, M. [Imperial College London, Department of Materials, London SW7 2AZ (United Kingdom); Dashwood, R. [Imperial College London, Department of Materials, London SW7 2AZ (United Kingdom); Inman, D. [Imperial College London, Department of Materials, London SW7 2AZ (United Kingdom)

    2006-08-10

    Ti-W alloys were produced via electrochemical reduction of TiO{sub 2}-WO{sub 3} mixed oxide preforms in a pre-electrolysed, molten calcium chloride electrolyte at 1173 K. Electrolysis voltages of 1500-3200 mV were applied for times ranging from 6 to 24 h across a graphite anode and Grade 2 commercial purity (CP) titanium cathodic current collector, which supported the ceramic precursors. Low-oxygen, homogeneous material was subsequently water washed and characterized to determine the level of residual species remaining from the reduction process, such as Cl and Ca. The microstructure (porosity and microchemistry) of the reduced material and microstructural examination of the mixed oxide feedstock (particle morphology, size and chemistry) were characterized using a field emission gun scanning electron microscope (FEG-SEM) with backscattered electron imaging (BSE) and X-ray energy dispersive spectrometry (X-EDS)

  17. Kinetics and mechanism of the oxidation of some neutral and acidic -amino acids by tetrabutylammonium tribromide

    Indian Academy of Sciences (India)

    Raghvendra Shukla; Pradeep K Sharma; Kalyan K Banerji

    2004-03-01

    The oxidation of eleven amino acids by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid results in the formation of the corresponding carbonyl compounds and ammonia. The reaction is first order with respect to TBATB. Michaelis-Menten type kinetics is observed with some of the amino acids while others exhibit second-order dependence. It failed to induce polymerization of acrylonitrile. The effect of solvent composition indicate that the rate of reaction increases with increase in the polarity of the medium. Addition of tetrabutylammonium chloride has no effect on the rate of oxidation. Addition of bromide ion causes decrease in the oxidation rate but only to a limiting value. The reaction is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.

  18. Kinetics of Oxidation of 3-Benzoylpropionic Acid by N-Bromoacetamide in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    N. A. Mohamed Farook

    2011-01-01

    Full Text Available The kinetics of oxidation of 3-benzoylpropionic acid (KA with N-bromoacetamide (NBA have been studied potentiometrically in 50:50 (v/v aqueous acetic acid medium at 298 K The reaction was first order each with respect to [KA], [NBA] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of acetamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. A mechanism consistent with observed results have been proposed and the related rate law was deduced.

  19. Bond energies in polyunsaturated acids and kinetics of co-oxidation of protiated and deuterated acids

    Science.gov (United States)

    Andrianova, Z. S.; Breslavskaya, N. N.; Pliss, E. M.; Buchachenko, A. L.

    2016-10-01

    A computational program specially designed to analyze co-oxidation of substances in mixtures is suggested. The rigorous kinetic scheme of 32 reactions describing co-oxidation of isotope differing polyunsaturated fatty acids was computed to enlighten experimentally detected enormously large H/D isotope effects. The latter were shown to depend on the kinetic chain length and exhibit two extreme regimes of short and long chains which characterize isotope effects on the initiation and propagation chain reactions of hydrogen (deuterium) atom abstraction. No protective effect of deuterated polyunsaturated acids on the oxidation of protiated acids was detected. Protective effect of the deuterated compounds on the biologically important processes seems to be induced by the low yield of products formed in the chain termination reactions due to the low rate of initiation by deuterated compounds.

  20. Refsum disease, peroxisomes and phytanic acid oxidation: a review.

    Science.gov (United States)

    Wanders, R J; Jansen, G A; Skjeldal, O H

    2001-11-01

    Refsum disease was first recognized as a distinct disease entity by Sigvald Refsum in the 1940s. The discovery of markedly elevated levels of the branched-chain fatty acid phytanic acid in certain patients marked Refsum disease as a disorder of lipid metabolism. Although it was immediately recognized that the accumulation of phytanic acid is due to its deficient breakdown in Refsum disease patients, the true enzymatic defect remained mysterious until recently. A major breakthrough in this respect was the resolution of the mechanism of phytanic acid alpha-oxidation in humans. In this review we describe the many aspects of Refsum disease from the clinical signs and symptoms to the enzyme and molecular defect plus the recent identification of genetic heterogeneity in Refsum disease.

  1. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2012-06-01

    Full Text Available In this work, oxidized nanocellulose (ONC was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl-N’-(3-dimethylaminopropyl carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, the intermolecular interaction of amino acids and peptides was avoided and uniform coupling of these molecules on ONC was achieved. The coupling reaction was very fast in mild conditions and without alteration of the polysaccharide. The coupling products (ONC-amino acids and ONC-peptides were characterized by transmission electron microscopy and by the absorption, emission, Fourier transform infrared spectroscopy (FTIR and X-ray photoelectron spectroscopy (XPS spectroscopic techniques.

  2. Coordinated safeguards for materials management in a mixed-oxide fuel facility

    Energy Technology Data Exchange (ETDEWEB)

    Shipley, J.P.; Cobb, D.D.; Dietz, R.J.; Evans, M.L.; Schelonka, E.P.; Smith, D.B.; Walton, R.B.

    1977-02-01

    A coordinated safeguards system is described for safeguarding strategic quantities of special nuclear materials in mixed-oxide recycle fuel fabrication facilities. The safeguards system is compatible with industrial process requirements and combines maximum effectiveness consistent with modest cost and minimal process interference. It is based on unit process accounting using a combination of conventional and state-of-the-art NDA measurement techniques. The effectiveness of the system against single and multiple thefts is evaluated using computer modeling and simulation techniques.

  3. Mineral and iron oxidation at low temperatures by pure and mixed cultures of acidophilic microorganisms.

    Science.gov (United States)

    Dopson, Mark; Halinen, Anna-Kaisa; Rahunen, Nelli; Ozkaya, Bestamin; Sahinkaya, Erkan; Kaksonen, Anna H; Lindström, E Börje; Puhakka, Jaakko A

    2007-08-01

    An enrichment culture from a boreal sulfide mine environment containing a low-grade polymetallic ore was tested in column bioreactors for simulation of low temperature heap leaching. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequencing revealed the enrichment culture contained an Acidithiobacillus ferrooxidans strain with high 16S rRNA gene similarity to the psychrotolerant strain SS3 and a mesophilic Leptospirillum ferrooxidans strain. As the mixed culture contained a strain that was within a clade with SS3, we used the SS3 pure culture to compare leaching rates with the At. ferrooxidans type strain in stirred tank reactors for mineral sulfide dissolution at various temperatures. The psychrotolerant strain SS3 catalyzed pyrite, pyrite/arsenopyrite, and chalcopyrite concentrate leaching. The rates were lower at 5 degrees C than at 30 degrees C, despite that all the available iron was in the oxidized form in the presence of At. ferrooxidans SS3. This suggests that although efficient At. ferrooxidans SS3 mediated biological oxidation of ferrous iron occurred, chemical oxidation of the sulfide minerals by ferric iron was rate limiting. In the column reactors, the leaching rates were much less affected by low temperatures than in the stirred tank reactors. A factor for the relatively high rates of mineral oxidation at 7 degrees C is that ferric iron remained in the soluble phase whereas, at 21 degrees C the ferric iron precipitated. Temperature gradient analysis of ferrous iron oxidation by this enrichment culture demonstrated two temperature optima for ferrous iron oxidation and that the mixed culture was capable of ferrous iron oxidation at 5 degrees C.

  4. Downscaled anodic oxidation process for aluminium in oxalic acid

    Science.gov (United States)

    Sieber, M.; Morgenstern, R.; Kuhn, D.; Hackert-Oschätzchen, M.; Schubert, A.; Lampke, T.

    2017-03-01

    The increasing multi-functionality of parts and assemblies in several fields of engineering demands, amongst others, highly functionalised surfaces. For the different applications, on the one hand, there is a need to scale up surface modification processes originating in the nano- and micro-scale. On the other hand, conventional macro-scale surface refinement methods offer a huge potential for application in the said nano- and micro-scale. The anodic oxidation process, which is established especially for aluminium and its alloys, allows the formation of oxide ceramic layers on the surface. The build-up of an oxide ceramic coating comes along with altered chemical, tribological and electrical surface properties. As a basis for further investigations regarding the use of the anodic oxidation process for micro-scale-manufacturing, the scale effects of oxalic acid anodising on commercially pure aluminium as well as on the AlZn5.5MgCu alloy are addressed in the present work. The focus is on the amount of oxide formed during a potentiostatic process in relation to the exchanged amount of charge. Further, the hardness of the coating as an integral measure to assess the porous oxide structure is approached by nano-indentation technique.

  5. Effects of Transition-Metal Mixing on Na Ordering and Kinetics in Layered P 2 Oxides

    Science.gov (United States)

    Zheng, Chen; Radhakrishnan, Balachandran; Chu, Iek-Heng; Wang, Zhenbin; Ong, Shyue Ping

    2017-06-01

    Layered P 2 oxides are promising cathode materials for rechargeable sodium-ion batteries. In this work, we systematically investigate the effects of transition-metal (TM) mixing on Na ordering and kinetics in the NaxCo1 -yMnyO2 model system using density-functional-theory (DFT) calculations. The DFT-predicted 0-K stability diagrams indicate that Co-Mn mixing reduces the energetic differences between Na orderings, which may account for the reduction of the number of phase transformations observed during the cycling of mixed-TM P 2 layered oxides compared to a single TM. Using ab initio molecular-dynamics simulations and nudged elastic-band calculations, we show that the TM composition at the Na(1) (face-sharing) site has a strong influence on the Na site energies, which in turn impacts the kinetics of Na diffusion towards the end of the charge. By employing a site-percolation model, we establish theoretical upper and lower bounds for TM concentrations based on their effect on Na(1) site energies, providing a framework to rationally tune mixed-TM compositions for optimal Na diffusion.

  6. Methodologies For Characterising Mixed Conducting Oxides For Oxygen Membrane And SOFC Cathode Application

    DEFF Research Database (Denmark)

    Hendriksen, Peter Vang; Søgaard, Martin; Plonczak, Pawel

    2012-01-01

    Two methods for detailed characterization of the process of oxygen exchange between the gas phase and a mixed conducting solid oxide are discussed. First, the use of solid electrolyte probes for measuring the change in oxygen activity over the surface of a mixed conductor is presented and advanta......Two methods for detailed characterization of the process of oxygen exchange between the gas phase and a mixed conducting solid oxide are discussed. First, the use of solid electrolyte probes for measuring the change in oxygen activity over the surface of a mixed conductor is presented...... and advantages of the technique discussed. Secondly, the use of thin film model electrodes is treated. Studies of thin films applied by PLD on both sides of a YSZ single crystal are presented for three different film materials; La0.85Sr0.15MnO3, La0.6Sr0.4Fe0.8Co0.2O3 and La0.6Sr0.4CoO3. Variations in electrode...

  7. Catalytic combustion of soot over Ru-doped mixed oxides catalysts

    Institute of Scientific and Technical Information of China (English)

    LF Nascimento; RF Martins; OA Serra

    2014-01-01

    We employed modified substrates as outer heterogeneous catalysts to reduce the soot originating from the incomplete die-sel combustion. Here, we proposed that ceria (CeO2)-based catalysts could lower the temperature at which soot combustion occurred from 610 ºC to values included in the operation range of diesel exhausts (270-400 ºC). Here, we used the sol-gel method to synthesize catalysts based on mixed oxides (ZnO:CeO2) deposited on cordierite substrates, and modified by ruthenium nanoparticles. The presence of ZnO in these mixed oxides produced defects associated with oxygen vacancies, improving thermal stability, redox potential, sulfur resistance, and oxygen storage. We evaluated the morphological and structural properties of the material by X-ray diffraction (XRD), Brumauer-emmett-teller method (BET), temperature programmed reduction (H2-TPR), scanning electron micros-copy (SEM), and transmission electron microscopy (TEM). We investigated how the addition of Ru (0.5 wt.%) affected the catalytic activity of ZnO:CeO2 in terms of soot combustion. Thermogravimetric analysis (TG/DTA) revealed that presence of the catalyst de-creased the soot combustion temperature by 250 ºC, indicating that the oxygen species arose at low temperatures, which was the main reason for the high reactivity of the oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy (DRS) showed that the catalyst containing Ru on the mixed oxide-impregnated cordierite samples efficiently oxidized soot in a diesel stationary motor:soot emission decreased 80%.

  8. Oxidized fatty acids as inter-kingdom signaling molecules.

    Science.gov (United States)

    Pohl, Carolina H; Kock, Johan L F

    2014-01-20

    Oxylipins or oxidized fatty acids are a group of molecules found to play a role in signaling in many different cell types. These fatty acid derivatives have ancient evolutionary origins as signaling molecules and are ideal candidates for inter-kingdom communication. This review discusses examples of the ability of organisms from different kingdoms to "listen" and respond to oxylipin signals during interactions. The interactions that will be looked at are signaling between animals and plants; between animals and fungi; between animals and bacteria and between plants and fungi. This will aid in understanding these interactions, which often have implications in ecology, agriculture as well as human and animal health.

  9. Enhanced formic acid oxidation on Cu-Pd nanoparticles

    Science.gov (United States)

    Dai, Lin; Zou, Shouzhong

    Developing catalysts with high activity and high resistance to surface poisoning remains a challenge in direct formic acid fuel cell research. In this work, copper-palladium nanoparticles were formed through a galvanic replacement process. After electrochemically selective dissolution of surface Cu, Pd-enriched Cu-Pd nanoparticles were formed. These particles exhibit much higher formic acid oxidation activities than that on pure Pd nanoparticles, and they are much more resistant to the surface poisoning. Possible mechanisms of catalytic activity enhancement are briefly discussed.

  10. Synthesis of docosahexaenoic acid from eicosapentaenoic acid in retina neurons protects photoreceptors from oxidative stress.

    Science.gov (United States)

    Simón, María Victoria; Agnolazza, Daniela L; German, Olga Lorena; Garelli, Andrés; Politi, Luis E; Agbaga, Martin-Paul; Anderson, Robert E; Rotstein, Nora P

    2016-03-01

    Oxidative stress is involved in activating photoreceptor death in several retinal degenerations. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in the retina, protects cultured retina photoreceptors from apoptosis induced by oxidative stress and promotes photoreceptor differentiation. Here, we investigated whether eicosapentaenoic acid (EPA), a metabolic precursor to DHA, had similar effects and whether retinal neurons could metabolize EPA to DHA. Adding EPA to rat retina neuronal cultures increased opsin expression and protected photoreceptors from apoptosis induced by the oxidants paraquat and hydrogen peroxide (H2 O2 ). Palmitic, oleic, and arachidonic acids had no protective effect, showing the specificity for DHA. We found that EPA supplementation significantly increased DHA percentage in retinal neurons, but not EPA percentage. Photoreceptors and glial cells expressed Δ6 desaturase (FADS2), which introduces the last double bond in DHA biosynthetic pathway. Pre-treatment of neuronal cultures with CP-24879 hydrochloride, a Δ5/Δ6 desaturase inhibitor, prevented EPA-induced increase in DHA percentage and completely blocked EPA protection and its effect on photoreceptor differentiation. These results suggest that EPA promoted photoreceptor differentiation and rescued photoreceptors from oxidative stress-induced apoptosis through its elongation and desaturation to DHA. Our data show, for the first time, that isolated retinal neurons can synthesize DHA in culture. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in retina photoreceptors, and its precursor, eicosapentaenoic acid (EPA) have multiple beneficial effects. Here, we show that retina neurons in vitro express the desaturase FADS2 and can synthesize DHA from EPA. Moreover, addition of EPA to these cultures protects photoreceptors from oxidative stress and promotes their differentiation through its metabolization to DHA.

  11. Catalysis of the rare earth containing mixed oxides Ln2CuO4 in phenol hydroxylation

    Institute of Scientific and Technical Information of China (English)

    刘持标; 赵震; 叶兴凯; 吴越

    1997-01-01

    Mixed oxides Ln2CuO4±λ(Ln=La,Pr,Nd,Sm,Gd) with K2NiF4 structure were prepared Their crystal structures were studied with XRD and IR spectra.Meanwhile,the average valence of Cu ions and non stoichiometric oxygen (λ) were determined through chemical analyses.Catalysis of the above-mentioned mixed oxides in the phenol hydroxylation was investigated.Results show that the catalysis of these mixed oxides has close relation with their structures and composition.Substitution of A site atom in Ln2CuO4λ has a great influence on then eatalysis in the phenol hydroxylation.

  12. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

    Directory of Open Access Journals (Sweden)

    S.M. Kemdeo

    2010-10-01

    Full Text Available TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reaction. Catalyst calcined at higher temperatures showed the negative influence on o-xylene conversion and 4-nitro-o-xylene selectivity. Conversion can be correlated with the presence of strong Brönsted acid sites over the catalyst surface whereas change in selectivity was found attributed to the pore diameter of the catalyst. These catalysts also performed satisfactorily, when used for nitration of other aromatics. No use of corrosive sulfuric acid and efficient reusability of the catalyst make the process environmentally friendly and economic. ©2010 BCREC UNDIP. All rights reserved(Received: 9th February 2010, Revised: 5th March 2010; Accepted: 18th March 2010[How to Cite: S.M. Kemdeo, V.S. Sapkal, G.N. Chaudhari. (2010. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene. Bulletin of Chemical Reaction Engineering and Catalysis, 5(1: 39-49. doi:10.9767/bcrec.5.1.776.39-49][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.5.1.776.39-49 ]Cited by in: Taylor Francis |

  13. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

    Directory of Open Access Journals (Sweden)

    S.M. Kemdeo

    2010-10-01

    Full Text Available TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reaction. Catalyst calcined at higher temperatures showed the negative influence on o-xylene conversion and 4-nitro-o-xylene selectivity. Conversion can be correlated with the presence of strong Brönsted acid sites over the catalyst surface whereas change in selectivity was found attributed to the pore diameter of the catalyst. These catalysts also performed satisfactorily, when used for nitration of other aromatics. No use of corrosive sulfuric acid and efficient reusability of the catalyst make the process environmentally friendly and economic. ©2010 BCREC UNDIP. All rights reserved(Received: 9th February 2010, Revised: 5th March 2010; Accepted: 18th March 2010[How to Cite: S.M. Kemdeo, V.S. Sapkal, G.N. Chaudhari. (2010. Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene. Bulletin of Chemical Reaction Engineering and Catalysis, 5(1: 39-49. doi:10.9767/bcrec.5.1.7126.39-49][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.5.1.7126.39-49 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/7126 ]Cited by in: Taylor Francis |

  14. Free fatty acid oxidation in insulin resistance and obesity

    OpenAIRE

    Abel, E. Dale

    2010-01-01

    The growing worldwide epidemic of obesity and diabetes portends a significant increase in cardiovascular disease. Obesity is associated with insulin resistance, and there is growing evidence that these conditions independently increase the risk of heart failure. Changes in myocardial substrate utilization develop in obesity and insulin resistance, and are characterized by increased fatty acid oxidation and utilization, and decreased glucose utilization. This paper will review the evidence for...

  15. Glycolic acid production using ethylene glycol-oxidizing microorganisms.

    Science.gov (United States)

    Kataoka, M; Sasaki, M; Hidalgo, A R; Nakano, M; Shimizu, S

    2001-10-01

    Screening for microorganisms oxidizing ethylene glycol to glycolic acid was carried out. Among stock cultures, several yeasts and acetic acid bacteria showed high glycolic acid producing activity. Pichia naganishii AKU 4267 formed the highest concentration of glycolic acid, 35.3 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 26.0%). Among soil isolates, Rhodotorula sp. 3Pr-126, isolated using propylene glycol as a sole carbon source, formed the highest concentration of glycolic acid, 25.1 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 18.5%). Rhodotorula sp. 3Pr-126 showed higher activity toward 20% (v/v) ethylene glycol than P. naganishii AKU 4267. Optimization of the conditions for glycolic acid production was investigated using P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126. Under the optimized conditions, P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126 formed 105 and 110 g/l of glycolic acid (corrected molar conversion yields, 88.0 and 92.2%) during 120 h of reaction, respectively.

  16. Catalytic wet-oxidation of a mixed liquid waste: COD and AOX abatement.

    Science.gov (United States)

    Goi, D; de Leitenburg, C; Trovarelli, A; Dolcetti, G

    2004-12-01

    A series of catalytic wet oxidation (CWO) reactions, at temperatures of 430-500 K and in a batch bench-top pressure vessel were carried out utilizing a strong wastewater composed of landfill leachate and heavily organic halogen polluted industrial wastewater. A CeO2-SiO2 mixed oxide catalyst with large surface area to assure optimal oxidation performance was prepared. The catalytic process was examined during batch reactions controlling Chemical Oxygen Demand (COD) and Adsorbable Organic Halogen (AOX) parameters, resulting AOX abatement to achieve better effect. Color and pH were also controlled during batch tests. A simple first order-two stage reaction behavior was supposed and verified with the considered parameters. Finally an OUR test was carried out to evaluate biodegradability changes of wastewater as a result of the catalytic reaction.

  17. Evaluation of the Protein Requirement in Chinese Young Adults Using the Indicator Amino Acid Oxidation Technique

    Institute of Scientific and Technical Information of China (English)

    LI Min; ZHANG Yu Hui; WANG Zhi Ling; GOU Ling Yan; LI Wei Dong; TIAN Yuan; HU Yi Chun; WANG Rui; PIAO Jian Hua; YANG Xiao Guang

    2013-01-01

    Objective To accurately calculate the protein requirements in Chinese young adults using the indicator amino acid oxidation technique. Methods Nine women and ten men received a restricted daily level of protein intake (0.75, 0.82, 0.89, 0.97, and 1.05 g/kg), along with L-[1-13C]-leucine. Subjects’ protein requirement was determined by a biphasic linear regression crossover analysis of F13CO2 data. In doing so, a breakpoint at the minimal rate of appearance of 13CO2 expiration specific to each level of dietary protein was identified. This trial was registered with the Chinese clinical trial registry as ChiCTR-ONC-11001407. Results The Estimated Average Requirement (EAR) and the Recommended Nutrient Intake (RNI) of protein for healthy Chinese young adults were determined to be 0.87 and 0.98 g/(kg·d), respectively, based on the indicator amino acid oxidation technique. Conclusion The EAR and RNI of mixed protein are 5% and 16% that are lower than the current proposed EAR and RNI (0.92 and 1.16 g/(kg·d), respectively), as determined by the nitrogen balance method. The respective EAR and RNI recommendations of 0.87 and 0.98 g/(kg·d) of mixed protein are estimated to be reasonable and suitable for Chinese young adults.

  18. Stearic acid protects primary cultured cortical neurons against oxidative stress

    Institute of Scientific and Technical Information of China (English)

    Ze-jian WANG; Cui-ling LIANG; Guang-mei LI; Cai-yi YU; Ming YIN

    2007-01-01

    Aim: To observe the effects of stearic acid against oxidative stress in primary cultured cortical neurons. Methods: Cortical neurons were exposed to glutamate,hydrogen peroxide (H202), or NaN3 insult in the presence or absence of stearic acid. Cell viability of cortical neurons was determined by MTT assay and LDH release. Endogenous antioxidant enzymes activity[superoxide dismutases (SOD),glutathione peroxidase (GSH-Px), and catalase (CAT)] and lipid peroxidation in cultured cortical neurons were evaluated using commercial kits. {3-[1(p-chloro-benzyl)-5-(isopropyl)-3-t-butylthiondol-2-yl]-2,2-dimethylpropanoic acid, Na}[MK886; 5 pmol/L; a noncompetitive inhibitor of proliferator-activated receptor(PPAR)α], bisphenol A diglycidyl ether (BADGE; 100 μmol/L; an antagonist of PPARγ), and cycloheximide (CHX; 30 μmol/L, an inhibitor of protein synthesis)were tested for their effects on the neuroprotection afforded by stearic acid.Western blotting was used to determine the PPARγ protein level in cortical neurons.Results: Stearic acid dose-dependently protected cortical neurons against glutamate or H202 injury and increased glutamate uptake in cultured neurons.This protection was concomitant to the inhibition of lipid peroxidation and to the promotion activity of Cu/Zn SOD and CAT in cultured cortical neurons. Its neuroprotective effects were completely blocked by BADGE and CHX. After incubation with H2O2 for 24 h, the expression of the PPARγ protein decreased significantly (P<0.05), and the inhibitory effect of H2O2 on the expression of PPARγ can be attenuated by stearic acid. Conclusion: Stearic acid can protect cortical neurons against oxidative stress by boosting the internal antioxidant enzymes.Its neuroprotective effect may be mainly mediated by the activation of PPARγ and new protein synthesis in cortical neurons.

  19. Late-occurring pulmonary pathologies following inhalation of mixed oxide (uranium + plutonium oxide) aerosol in the rat.

    Science.gov (United States)

    Griffiths, N M; Van der Meeren, A; Fritsch, P; Abram, M-C; Bernaudin, J-F; Poncy, J L

    2010-09-01

    Accidental exposure by inhalation to alpha-emitting particles from mixed oxide (MOX: uranium and plutonium oxide) fuels is a potential long-term health risk to workers in nuclear fuel fabrication plants. For MOX fuels, the risk of lung cancer development may be different from that assigned to individual components (plutonium, uranium) given different physico-chemical characteristics. The objective of this study was to investigate late effects in rat lungs following inhalation of MOX aerosols of similar particle size containing 2.5 or 7.1% plutonium. Conscious rats were exposed to MOX aerosols and kept for their entire lifespan. Different initial lung burdens (ILBs) were obtained using different amounts of MOX. Lung total alpha activity was determined by external counting and at autopsy for total lung dose calculation. Fixed lung tissue was used for anatomopathological, autoradiographical, and immunohistochemical analyses. Inhalation of MOX at ILBs ranging from 1-20 kBq resulted in lung pathologies (90% of rats) including fibrosis (70%) and malignant lung tumors (45%). High ILBs (4-20 kBq) resulted in reduced survival time (N = 102; p MOX, similar to results for industrial plutonium oxide alone (1.9% Gy). Staining with antibodies against Surfactant Protein-C, Thyroid Transcription Factor-1, or Oct-4 showed differential labeling of tumor types. In conclusion, late effects following MOX inhalation result in similar risk for development of lung tumors as compared with industrial plutonium oxide.

  20. Selective oxidations on vanadiumoxide containing amorphous mixed oxides (AMM-V) with tert.-butylhydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Y.; Hunnius, M.; Storck, S.; Maier, W.F. [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    1998-12-31

    The catalytic oxygen transfer properties of vanadium containing zeolites and vanadium based sol-gel catalysts with hydrogen peroxides are well known. The severe problem of vanadium leaching caused by the presence of the by-product water has been addressed. To avoid any interference with homogeneously catalyzed reactions, our study focusses on selective oxidations in a moisture-free medium with tert.-butylhydroperoxide. We have investigated the catalytic properties of amorphous microporous materials based on SiO{sub 2}, TiO{sub 2}, ZrO{sub 2} and Al{sub 2}O{sub 3} as matrix material and studied the effects of surface polarity on the oxidation of 1-octene and cyclohexane. (orig.)

  1. Mixed

    Directory of Open Access Journals (Sweden)

    Pau Baya

    2011-05-01

    Full Text Available Remenat (Catalan (Mixed, "revoltillo" (Scrambled in Spanish, is a dish which, in Catalunya, consists of a beaten egg cooked with vegetables or other ingredients, normally prawns or asparagus. It is delicious. Scrambled refers to the action of mixing the beaten egg with other ingredients in a pan, normally using a wooden spoon Thought is frequently an amalgam of past ideas put through a spinner and rhythmically shaken around like a cocktail until a uniform and dense paste is made. This malleable product, rather like a cake mixture can be deformed pulling it out, rolling it around, adapting its shape to the commands of one’s hands or the tool which is being used on it. In the piece Mixed, the contortion of the wood seeks to reproduce the plasticity of this slow heavy movement. Each piece lays itself on the next piece consecutively like a tongue of incandescent lava slowly advancing but with unstoppable inertia.

  2. Surface composition and catalytic activity of La-Fe mixed oxides for methane oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fengxiang [School of Chemistry, Beijing Institute of Technology, Liangxiang East Road, Beijing 102488 (China); Li, Zhanping [Analysis Center, Tsinghua University, Beijing 100084 (China); Ma, Hongwei [School of Chemistry, Beijing Institute of Technology, Liangxiang East Road, Beijing 102488 (China); Gao, Zhiming, E-mail: zgao@bit.edu.cn [School of Chemistry, Beijing Institute of Technology, Liangxiang East Road, Beijing 102488 (China)

    2015-10-01

    Graphical abstract: - Highlights: • The sample with La/Fe atomic ratio of 0.94 is single phase perovskite La{sub 0.94}FeO{sub 3−d}. • The excess ironic oxide exists on the surface of the perovskite crystallites. • La{sup 3+} ions are enriched on surface of the oxides even for the La{sub 0.68}Fe sample. - Abstract: Four La-Fe oxide samples with La/Fe atomic ratio y = 1.02 ∼ 0.68 (denoted as LayFe) were prepared by the citrate method. The samples had a decreased specific surface area with the La/Fe atomic ratio decreasing. XRD pattern proved that the sample La{sub 0.94}Fe is single phase perovskite La{sub 0.94}FeO{sub 3−d}. Phase composition of the samples was estimated by the Rietveld refinement method. XPS analyses indicate that La{sup 3+} ions are enriched on surface of crystallites for all the samples, and surface carbonate ions are relatively abundant on the samples La{sub 1.02}Fe and La{sub 0.94}Fe. Catalytic activity for methane oxidation per unit surface area of the samples is in the order of La{sub 0.68}Fe > La{sub 0.76}Fe > La{sub 0.94}Fe > La{sub 1.02}Fe both in the presence and in the absence of gaseous oxygen. A reason for this order would be the higher concentration of Fe{sup 3+} ion on the surface of the samples La{sub 0.68}Fe and La{sub 0.76}Fe.

  3. Aromatic nitrations by mixed acid. Fast liquid-liquid reaction regime

    NARCIS (Netherlands)

    Zaldivar, J.M.; Molga, E.J.; Alos, M.A.; Hernandez, H.; Westerterp, K.R.

    1996-01-01

    Aromatic nitration by mixed acid was selected as a specific case of heterogeneous liquid-liquid reaction. An extensive experimental programme was followed using adiabatic and heat flow calorimetry and pilot reactor experiments, supported by chemical analysis. A series of nitration experiments was ca

  4. The Acid Soluble Disulphide and Mixed Disulphide Levels of Some Normal Tissues and Transplanted Tumours

    Science.gov (United States)

    Calcutt, G.; Ting, S. M.

    1970-01-01

    The acid soluble disulphides and mixed disulphides of a range of normal rat and mouse tissues and a number of transplanted rat or mouse tumours were measured. The result were considered in relation to other workers' data. It is noted that more radioresponsive tissues have higher levels than the more radioresistant tissues. PMID:5475758

  5. Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ge-Fu; Wu, Peng; Wei, Qun-Shan; Lin, Jian-yi; Liu, Hai-Ning [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Gao, Yan-Li [China University of Geosciences, Wuhan 430074 (China)

    2010-08-15

    Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H{sub 2}) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m{sup 3} d, hydraulic retention time (HRT) of 6 h and temperature of (35 {+-} 1) C, when the pH value, alkalinity and oxidation-reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO{sub 3}/L, and -220 to -250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H{sub 2} volume content was estimated to be 48-53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H{sub 2} production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H{sub 2} production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H{sub 2} production from high-strength chemical wastewater. (author)

  6. Physiological effects of γ-linolenic acid and sesamin on hepatic fatty acid synthesis and oxidation.

    Science.gov (United States)

    Ide, Takashi; Iwase, Haruka; Amano, Saaya; Sunahara, Saki; Tachihara, Ayuka; Yagi, Minako; Watanabe, Tsuyoshi

    2017-03-01

    Interrelated effects of γ-linolenic acid (GLA) and sesamin, a sesame lignan, on hepatic fatty acid synthesis and oxidation were examined. Rats were fed experimental diets supplemented with 0 or 2 g/kg sesamin (1:1 mixture of sesamin and episesamin) and containing 100 g/kg of palm oil (saturated fat), safflower oil rich in linoleic acid, or oil of evening primrose origin containing 43% GLA (GLA oil) for 18 days. In rats fed sesamin-free diets, GLA oil, compared with other oils, increased the activity and mRNA levels of various enzymes involved in fatty acid oxidation, except for some instances. Sesamin greatly increased these parameters, and the enhancing effects of sesamin on peroxisomal fatty acid oxidation rate and acyl-CoA oxidase, enoyl-CoA hydratase and acyl-CoA thioesterase activities were more exaggerated in rats fed GLA oil than in the animals fed other oils. The combination of sesamin and GLA oil also synergistically increased the mRNA levels of some peroxisomal fatty acid oxidation enzymes and of several enzymes involved in fatty acid metabolism located in other cell organelles. In the groups fed sesamin-free diets, GLA oil, compared with other oils, markedly reduced the activity and mRNA levels of various lipogenic enzymes. Sesamin reduced all these parameters, except for malic enzyme, in rats fed palm and safflower oils, but the effects were attenuated in the animals fed GLA oil. These changes by sesamin and fat type accompanied profound alterations in serum lipid levels. This may be ascribable to the changes in apolipoprotein-B-containing lipoproteins.

  7. The kinetics of oxidation of bilirubin and ascorbic acid in solution

    Science.gov (United States)

    Solomonov, A. V.; Rumyantsev, E. V.; Kochergin, B. A.; Antina, E. V.

    2012-07-01

    The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin.

  8. Regulation and limitations to fatty acid oxidation during exercise

    DEFF Research Database (Denmark)

    Jeppesen, Jacob; Kiens, Bente

    2012-01-01

    Fatty acids (FA) as fuel for energy utilization during exercise originate from different sources: FA transported in the circulation either bound to albumin or as triacylglycerol (TG) carried by very low density lipoproteins (VLDL) and FA from lipolysis of muscle TG stores (IMTG). Despite a high...... rate of energy expenditure during high intensity exercise the total fatty acid oxidation is suppressed to below that observed during moderate intensity exercise. Although this has been known for many years, the mechanisms behind this phenomenon are still not fully elucidated. A failure of adipose...... tissue to deliver sufficient fatty acids to exercising muscle has been proposed, but evidence is emerging that factors within the muscle might be of more importance. The high rate of glycolysis during high intensity exercise might be the "driving force" via the increased production of acetyl CoA which...

  9. Kinetics and Mechanism of Oxidation of Glutamic Acid by N-Bromophthalimide in Aqueous Acidic Medium

    OpenAIRE

    2011-01-01

    The kinetics of oxidation of glutamic acid (Glu) with N-bromophthalimide (NBP) was studied in perchloric acid medium at 30 °C by potentiometric method. The reaction is first order each in NBP and glutamic acid and is negative fractional order in [H+]. Addition of KBr or the reaction product, phthalimide had no effect on the rate. Similarly variation of ionic strength of the medium did not affect the rate of the reaction. Also the rate increased with decrease in dielectric constant of the reac...

  10. Acetic acid enhances endurance capacity of exercise-trained mice by increasing skeletal muscle oxidative properties.

    Science.gov (United States)

    Pan, Jeong Hoon; Kim, Jun Ho; Kim, Hyung Min; Lee, Eui Seop; Shin, Dong-Hoon; Kim, Seongpil; Shin, Minkyeong; Kim, Sang Ho; Lee, Jin Hyup; Kim, Young Jun

    2015-01-01

    Acetic acid has been shown to promote glycogen replenishment in skeletal muscle during exercise training. In this study, we investigated the effects of acetic acid on endurance capacity and muscle oxidative metabolism in the exercise training using in vivo mice model. In exercised mice, acetic acid induced a significant increase in endurance capacity accompanying a reduction in visceral adipose depots. Serum levels of non-esterified fatty acid and urea nitrogen were significantly lower in acetic acid-fed mice in the exercised mice. Importantly, in the mice, acetic acid significantly increased the muscle expression of key enzymes involved in fatty acid oxidation and glycolytic-to-oxidative fiber-type transformation. Taken together, these findings suggest that acetic acid improves endurance exercise capacity by promoting muscle oxidative properties, in part through the AMPK-mediated fatty acid oxidation and provide an important basis for the application of acetic acid as a major component of novel ergogenic aids.

  11. Advanced oxidation processes of decomposing dichloroacetic acid and trichloroacetic acid in water

    Institute of Scientific and Technical Information of China (English)

    WANG Kun-ping; GUO Jin-song; YANG Min; JUNJI Hirotsuji; DENG Rong-sen; LIU Wei

    2008-01-01

    We studied the decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation processes (AOPs) constituted by the combinations of O3/UV, H2O2/UV, O3 /H2O2, and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV, the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV, closely followed by O3/UV. DCAA is much easier to decompose than TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3- in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process.

  12. Importance of acid-base equilibrium in electrocatalytic oxidation of formic acid on platinum.

    Science.gov (United States)

    Joo, Jiyong; Uchida, Taro; Cuesta, Angel; Koper, Marc T M; Osawa, Masatoshi

    2013-07-10

    Electro-oxidation of formic acid on Pt in acid is one of the most fundamental model reactions in electrocatalysis. However, its reaction mechanism is still a matter of strong debate. Two different mechanisms, bridge-bonded adsorbed formate mechanism and direct HCOOH oxidation mechanism, have been proposed by assuming a priori that formic acid is the major reactant. Through systematic examination of the reaction over a wide pH range (0-12) by cyclic voltammetry and surface-enhanced infrared spectroscopy, we show that the formate ion is the major reactant over the whole pH range examined, even in strong acid. The performance of the reaction is maximal at a pH close to the pKa of formic acid. The experimental results are reasonably explained by a new mechanism in which formate ion is directly oxidized via a weakly adsorbed formate precursor. The reaction serves as a generic example illustrating the importance of pH variation in catalytic proton-coupled electron-transfer reactions.

  13. Argonne National Laboratory`s photo-oxidation organic mixed waste treatment system - installation and startup testing

    Energy Technology Data Exchange (ETDEWEB)

    Shearer, T.L.; Nelson, R.A.; Torres, T.; Conner, C.; Wygmans, D.

    1997-09-01

    This paper describes the installation and startup testing of the Argonne National Laboratory (ANL-E) Photo-Oxidation Organic Mixed Waste Treatment System. This system will treat organic mixed (i.e., radioactive and hazardous) waste by oxidizing the organics to carbon dioxide and inorganic salts in an aqueous media. The residue will be treated in the existing radwaste evaporators. The system is installed in the Waste Management Facility at the ANL-E site in Argonne, Illinois. 1 fig.

  14. Optical and Chemical Properties of Mixed-valent Rhenium Oxide Films Synthesized by Reactive DC Magnetron Sputtering

    Science.gov (United States)

    2015-04-03

    AFRL-RX-WP-JA-2015-0178 OPTICAL AND CHEMICAL PROPERTIES OF MIXED- VALENT RHENIUM OXIDE FILMS SYNTHESIZED BY REACTIVE DC MAGNETRON...To) 06 May 2010 – 16 March 2015 4. TITLE AND SUBTITLE OPTICAL AND CHEMICAL PROPERTIES OF MIXED-VALENT RHENIUM OXIDE FILMS SYNTHESIZED BY REACTIVE ...DC MAGNETRON SPUTTERING (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) (see

  15. Nano-vanadium oxide thin films in mixed phase for microbolometer applications

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyam, A; Bharat Kumar Reddy, Y [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Nagendra, C L [LEOS, ISRO, Peenya Industrial Estate, Bangalore 560060 (India)], E-mail: manu@iitm.ac.in

    2008-10-07

    Among the several phases of vanadium oxide, mixed phases of VO{sub 2} and V{sub 2}O{sub 5} are preferred for uncooled micro-bolometers with low noise. The aim of this investigation is to achieve mixed phase VO{sub 2} and V{sub 2}O{sub 5} thin films with nanometre grain sizes and high temperature coefficient of resistance (TCR). Since the phase depends upon the oxygen reactivity, these vanadium oxide thin films are prepared by reactive electron beam evaporation at different oxygen flow rates and substrate temperatures. The mixed phases have been evaluated through x-ray diffraction and x-ray photo emission studies. The temperature dependence of resistance has shown that the films grown at 473 K with 2.8 x 10{sup -5} mbar chamber pressure of oxygen (VO{sub 2} : V{sub 2}O{sub 5} ratio of 36 : 64) have the highest TCR of -3.2 K{sup -1} with a reasonable low resistance (120 {omega}/square)

  16. Selective oxidations of a dithiolate complex produce a mixed sulfonate/thiolate complex.

    Science.gov (United States)

    Chohan, Balwant S; Maroney, Michael J

    2006-03-06

    Oxygenation or peroxidation of a planar, tetracoordinate, low-spin nickel(II) complex of a N2S2-donor ligand, (N,N'-dimethyl-N,N'-bis(2-mecaptoethyl)-1, 3-propanediaminato)nickel(II), proceeds via the formation of a mixed sulfinate/thiolate complex and leads to the production of a novel dimeric complex containing both sulfonate and thiolate ligands. Thus, reaction proceeds via selective oxidation of the sulfinate sulfur atom, leaving the thiolate reduced. The novel sulfonate/thiolate complex has been isolated and characterized by electospray ionization mass spectrometry and single-crystal X-ray diffraction. Crystals form in the monoclinic space group P2(1)/c with cell dimensions a = 8.4647(12) A, b = 12.592(3) A, and c = 12.531(2) A, angles alpha = gamma = 90 degrees and beta = 106.645(11) degrees , and Z = 2. The structure was refined to R = 5.20% and R(w) = 12.86% [I > 2sigma(I)]. The isolation of this mixed sulfonate/thiolate complex from oxidation of a mixed sulfinate/thiolate complex provides experimental evidence for the formation of a sulfonate ligand via a Ni-O-O-SO2R intermediate, as suggested by recent density functional theory calculations.

  17. Reduction Rates for Higher Americium Oxidation States in Nitric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, Travis Shane [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schmitt, Nicholas C [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-30

    The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show that the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.

  18. 'Low-acid' sulfide oxidation using nitrate-enriched groundwater

    Science.gov (United States)

    Donn, Michael; Boxall, Naomi; Reid, Nathan; Meakin, Rebecca; Gray, David; Kaksonen, Anna; Robson, Thomas; Shiers, Denis

    2016-04-01

    Acid drainage (AMD/ARD) is undoubtedly one of the largest environmental, legislative and economic challenges facing the mining industry. In Australia alone, at least 60m is spent on AMD related issues annually, and the global cost is estimated to be in the order of tens of billions US. Furthermore, the challenge of safely and economically storing or treating sulfidic wastes will likely intensify because of the trend towards larger mines that process increasingly higher volumes of lower grade ores and the associated sulfidic wastes and lower profit margins. While the challenge of managing potentially acid forming (PAF) wastes will likely intensify, the industrial approaches to preventing acid production or ameliorating the effects has stagnated for decades. Conventionally, PAF waste is segregated and encapsulated in non-PAF tips to limit access to atmospheric oxygen. Two key limitations of the 'cap and cover' approach are: 1) the hazard (PAF) is not actually removed; only the pollutant linkage is severed; and, 2) these engineered structures are susceptible to physical failure in short-to-medium term, potentially re-establishing that pollutant linkage. In an effort to address these concerns, CSIRO is investigating a passive, 'low-acid' oxidation mechanism for sulfide treatment, which can potentially produce one quarter as much acidity compared with pyrite oxidation under atmospheric oxygen. This 'low-acid' mechanism relies on nitrate, rather than oxygen, as the primary electron accepter and the activity of specifically cultured chemolithoautotrophic bacteria and archaea communities. This research was prompted by the observation that, in deeply weathered terrains of Australia, shallow (oxic to sub-oxic) groundwater contacting weathering sulfides are commonly inconsistent with the geochemical conditions produced by ARD. One key characteristic of these aquifers is the natural abundance of nitrate on a regional scale, which becomes depleted around the sulfide bodies, and

  19. Preparation and characterization of Cu-Ce-La mixed oxide as water-gas shift catalyst for fuel cells application

    Institute of Scientific and Technical Information of China (English)

    ZHI Keduan; LIU Quansheng; ZHAO Ruigang; HE Runxia; ZHANG Lifeng

    2008-01-01

    Cu-Ce-La mixed oxides were prepared by three precipitation methods (coprecipitation, homogeneous precipitation, and deposition precipitation) with variable precipitators and characterized using X-ray diffraction, BET, temperature-programmed reduction, and catalytic reaction for the water-gas shift. The Cu-Ce-La mixed oxide prepared by coprecipitation method with NaOH as precipitator presented the highest activity and thermal stability. Copper ion substituted quadrevalent ceria entered CeO2 (111) framework was in favor of activity and thermal stability of catalyst. The crystallinity of fresh catalysts increased with the reduction process. La3+ or Ce4+ substituted copper ion entered the CeO2 framework during reduction process. The coexistence of surface copper oxide (crystalline) and pure bulk crystalline copper oxide both contributed to the high activity and thermal stability of Cu-Ce-La mixes oxide catalyst.

  20. Influence of Gold on Ce-Zr-Co Fluorite-Type Mixed Oxide Catalysts for Ethanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Véronique Pitchon

    2012-02-01

    Full Text Available The effect of gold presence on carbon monoxide oxidation and ethanol steam reforming catalytic behavior of two Ce-Zr-Co mixed oxides catalysts with a constant Co charge and different Ce/Zr ratios was investigated. The Ce-Zr-Co mixed oxides were obtained by the pseudo sol-gel like method, based on metallic propionates polymerization and thermal decomposition, whereas the gold-supported Ce-Zr-Co mixed oxides catalysts were prepared using the direct anionic exchange. The catalysts were characterized using XRD, TPR, and EDXS-TEM. The presence of Au in doped Ce-Zr-Co oxide catalyst decreases the temperature necessary to reduce the cobalt and the cerium loaded in the catalyst and favors a different reaction pathway, improving the acetaldehyde route by ethanol dehydrogenation, instead of the ethylene route by ethanol dehydration or methane re-adsorption, thus increasing the catalytic activity and selectivity into hydrogen.

  1. Microstructure and oxygen evolution of Fe-Ce mixed oxides by redox treatment

    Science.gov (United States)

    Li, Kongzhai; Haneda, Masaaki; Ning, Peihong; Wang, Hua; Ozawa, Masakuni

    2014-01-01

    The relationship between structure and reduction/redox properties of Fe-Ce mixed oxides with a Fe content of 5, 10, 20 or 30 mol%, prepared by a coprecipitation method, were investigated by XRD, Raman, TEM, TPR and TPO techniques. It is found that all the iron ions can be incorporated into the ceria lattice to form a solid solution for the FeCe 5 (Fe 5%) sample, but amorphous or crystal Fe2O3 particles were found to be present on the Fe-Ce oxide samples with higher the iron content. The reducibility of single solid solution was much better than the pure CeO2, and the appearance of dispersed Fe2O3 particles improved the surface reducibility of materials. The iron ions incorporated into the CeO2 lattice accelerated the oxygen release from bulk to surface, and surface Fe2O3 particles in close contact to CeO2 acted as a catalyst for the reaction between solid solution and hydrogen. The microstructure of exposed Fe2O3 with Ce-Fe-O solid solution allows the Fe-Ce mixed oxides to own good reducibility and high OSC, which also counteracts the deactivation of the reducibility resulting from the sintering of materials in the redox cycling.

  2. Feasibility Study of 1/3 Thorium-Plutonium Mixed Oxide Core

    Directory of Open Access Journals (Sweden)

    Cheuk Wah Lau

    2014-01-01

    Full Text Available Thorium-plutonium mixed oxide (Th-MOX fuel has become one of the most promising solutions to reduce a large and increasing plutonium stockpile. Compared with traditional uranium-plutonium mixed oxide (U-MOX fuels, Th-MOX fuel has higher consumption rate of plutonium in LWRs. Besides, thorium based fuels have improved thermomechanical material properties compared with traditional U-MOX fuels. Previous studies on a full Th-MOX core have shown reduced efficiency in reactivity control mechanisms, stronger reactivity feedback, and a significantly lower fraction of delayed neutrons compared with a traditional uranium oxide (UOX core. These problems complicate the implementation of a full Th-MOX core in a similar way as for a traditional U-MOX core. In order to reduce and avoid some of these issues, the introduction of a lower fraction of Th-MOX fuel in the core is proposed. In this study, one-third of the assemblies are Th-MOX fuel, and the rest are traditional UOX fuel. The feasibility study is based on the Swedish Ringhals-3 PWR. The results show that the core characteristics are more similar to a traditional UOX core, and the fraction of delayed neutrons is within acceptable limits. Moreover, the damping of axial xenon oscillations induced by control rod insertions is almost 5 times more effective for the 1/3 Th-MOX core compared with the standard core.

  3. Solid-Liquid Equilibria of Succinic Acid in Cyclohexanone, Cyclohexanol and Their Mixed Solvents

    Institute of Scientific and Technical Information of China (English)

    FAN Lihua; MA Peisheng; SONG Weiwei

    2007-01-01

    Solubilities were measured for succinic acid dissolved in cyclohexanone, cyclohexanol and 5 of their mixed solvents at the temperature range from 291.85 K to 358.37 K using a dynamic method. The solubility data were regressed by λh equation, withthe average absolute relative deviation 3.47%. The binary interaction parameter is 0.306 7 for the mixed solvent of cyclohexanone and cyclohexanol was determined by correlating the experimental solubilities with the modified λh equation. When the binary interaction parameter was determined, it can be used to extrapolate the solubilities of succinic acid in mixed solvents of cyclohexanone and cyclohexanol at any proportion. The average absolute relative deviation was 7.69% by using the modified λh equation to correlate the solubility data, however, the average absolute relative deviation was 8.89% by using NRTL equation to correlate the solubility data. The results show that the accuracy of the modified λh equation is better than that of the NRTL equation for the solubility of succinic acid in the 5 mixed solvents of cyclohexanone and cyclohexanol.

  4. Effects of mixing procedure itself on the structure, viscosity, and spreadability of white petrolatum and salicylic acid ointment and the skin permeation of salicylic acid.

    Science.gov (United States)

    Kitagawa, Shuji; Fujiwara, Megumi; Okinaka, Yuta; Yutani, Reiko; Teraoka, Reiko

    2015-01-01

    White petrolatum is a mixture of solid and liquid hydrocarbons and its structure can be affected by shear stress. Thus, it might also induce changes in its rheological properties. In this study, we used polarization microscopy to investigate how different mixing methods affect the structure of white petrolatum. We used two different mixing methods, mixing using a rotation/revolution mixer and mixing using an ointment slab and an ointment spatula. The extent of the fragmentation and dispersal of the solid portion of white petrolatum depended on the mixing conditions. Next, we examined the changes in the structure of a salicylic acid ointment, in which white petrolatum was used as a base, induced by mixing and found that the salicylic acid solids within the ointment were also dispersed. In addition to these structural changes, the viscosity and thixotropic behavior of both test substances also decreased in a mixing condition-dependent manner. The reductions in these parameters were most marked after mixing with a rotation/revolution mixer, and similar results were obtained for spreadability. We also investigated the effects of mixing procedure on the skin accumulation and permeation of salicylic acid. They were increased by approximately three-fold after mixing. Little difference in skin accumulation or permeation was detected between the two mixing methods. These findings indicate that mixing procedures themselves affect the utility and physiological effects of white petrolatum-based ointments. Therefore, these effects should be considered when mixing is required for the clinical use of petrolatum-based ointments.

  5. Mitochondrial free fatty acid β-oxidation supports oxidative phosphorylation and proliferation in cancer cells.

    Science.gov (United States)

    Rodríguez-Enríquez, Sara; Hernández-Esquivel, Luz; Marín-Hernández, Alvaro; El Hafidi, Mohammed; Gallardo-Pérez, Juan Carlos; Hernández-Reséndiz, Ileana; Rodríguez-Zavala, José S; Pacheco-Velázquez, Silvia C; Moreno-Sánchez, Rafael

    2015-08-01

    Oxidative phosphorylation (OxPhos) is functional and sustains tumor proliferation in several cancer cell types. To establish whether mitochondrial β-oxidation of free fatty acids (FFAs) contributes to cancer OxPhos functioning, its protein contents and enzyme activities, as well as respiratory rates and electrical membrane potential (ΔΨm) driven by FFA oxidation were assessed in rat AS-30D hepatoma and liver (RLM) mitochondria. Higher protein contents (1.4-3 times) of β-oxidation (CPT1, SCAD) as well as proteins and enzyme activities (1.7-13-times) of Krebs cycle (KC: ICD, 2OGDH, PDH, ME, GA), and respiratory chain (RC: COX) were determined in hepatoma mitochondria vs. RLM. Although increased cholesterol content (9-times vs. RLM) was determined in the hepatoma mitochondrial membranes, FFAs and other NAD-linked substrates were oxidized faster (1.6-6.6 times) by hepatoma mitochondria than RLM, maintaining similar ΔΨm values. The contents of β-oxidation, KC and RC enzymes were also assessed in cells. The mitochondrial enzyme levels in human cervix cancer HeLa and AS-30D cells were higher than those observed in rat hepatocytes whereas in human breast cancer biopsies, CPT1 and SCAD contents were lower than in human breast normal tissue. The presence of CPT1 and SCAD in AS-30D mitochondria and HeLa cells correlated with an active FFA utilization in HeLa cells. Furthermore, the β-oxidation inhibitor perhexiline blocked FFA utilization, OxPhos and proliferation in HeLa and other cancer cells. In conclusion, functional mitochondria supported by FFA β-oxidation are essential for the accelerated cancer cell proliferation and hence anti-β-oxidation therapeutics appears as an alternative promising approach to deter malignant tumor growth.

  6. Kinetics and mechanism of the oxidation of some -hydroxy acids by hexamethylenetetramine-bromine

    Indian Academy of Sciences (India)

    Dimple Garg; Seema Kothari

    2004-11-01

    The oxidation of lactic acid, mandelic acid and ten monosubstituted mandelic acids by hexamethylenetetramine-bromine (HABR) in glacial acetic acid, leads to the formation of the corresponding oxoacid. The reaction is first order with respect to each of the hydroxy acids and HABR. It is proposed that HABR itself is the reactive oxidizing species. The oxidation of -deuteriomandelic acid exhibits the presence of a substantial kinetic isotope effect (/ = 5.91 at 298 K). The rates of oxidation of the substituted mandelic acids show excellent correlation with Brown’s + values. The reaction constants are negative. The oxidation exhibits an extensive cross conjugation between the electron-donating substituent and the reaction centre in the transition state. A mechanism involving transfer of a hydride ion from the acid to the oxidant is postulated.

  7. Low-temperature synthesis of Mn-based mixed metal oxides with novel fluffy structures as efficient catalysts for selective reduction of nitrogen oxides by ammonia.

    Science.gov (United States)

    Meng, Bo; Zhao, Zongbin; Chen, Yongsheng; Wang, Xuzhen; Li, Yong; Qiu, Jieshan

    2014-10-21

    A series of Mn-based mixed metal oxide catalysts (Co-Mn-O, Fe-Mn-O, Ni-Mn-O) with high surface areas were prepared via low temperature crystal splitting and exhibited extremely high catalytic activity for the low-temperature selective catalytic reduction of nitrogen oxides with ammonia.

  8. Electrocatalytic oxidation of formic acid and formaldehyde on nanoparticle decorated single walled carbon nanotubes.

    Science.gov (United States)

    Selvaraj, V; Grace, A Nirmala; Alagar, M

    2009-05-01

    A potent catalyst has been prepared consisting of platinum (Pt), and platinum-palladium (Pt-Pd) nanoparticles supported on purified single-walled carbon nanotubes (Pt/CNT and Pt-Pd/CNT). Electrochemical characteristics of formic acid and formaldehyde oxidation on these catalysts are investigated via cyclic voltammetric analysis in mixed 0.5 M HCOOH (or 0.5 M HCHO) and 0.5 M H(2)SO(4) solutions. The results imply that the Pt-Pd/CNT electrodes exhibit a better activity than the corresponding Pt nanoparticles modified SWCNT electrodes. The modified electrode exhibits significant electrocatalytic activity towards formic acid and formaldehyde oxidation, which may be attributed due to the uniform dispersion of nanoparticles on SWCNTs and the efficacy of Pd species in Pt-Pd system. Such nanoparticles modified CNT electrodes exhibit better catalytic behavior towards formic acid and formaldehyde than the corresponding carbon electrodes, indicating that the system studied in the present work is the more promising system for use in fuel cells.

  9. Plasma HDL reduces nonesterified fatty acid hydroperoxides originating from oxidized LDL: a mechanism for its antioxidant ability.

    Science.gov (United States)

    Kotosai, Mari; Shimada, Sachiko; Kanda, Mai; Matsuda, Namiko; Sekido, Keiko; Shimizu, Yoshibumi; Tokumura, Akira; Nakamura, Toshiyuki; Murota, Kaeko; Kawai, Yoshichika; Terao, Junji

    2013-06-01

    The antioxidant property of plasma high-density lipoprotein (HDL) is thought to be involved in potential anti-atherogenic effects but the exact mechanism is not known. We aimed to reveal the contribution of HDL on the elimination of lipid hydroperoxides (LOOH) derived from oxidized low-density lipoprotein (LDL). Oxidized LDL prepared by copper ion-induced oxidation contained nonesterified fatty acid hydroperoxides (FFA-OOH) and lysophosphatidylcholine (lysoPtdCho), in addition to cholesteryl ester hydroperoxides (CE-OOH) and phosphatidylcholine hydroperoxides (PtdCho-OOH). A platelet-activating factor-acetylhydrolase (PAF-AH) inhibitor suppressed formation of FFA-OOH and lysoPtdCho in oxidized LDL. Among LOOH species, FFA-OOH was preferentially reduced by incubating oxidized LDL with HDL. HDL exhibited selective FFA-OOH reducing ability if it was mixed with a liposomal solution containing FFA-OOH, CE-OOH and PtdCho-OOH. Two-electron reduction of the hydroperoxy group to the hydroxy group was confirmed by the formation of 13-hydroxyoctadecadienoic acid from 13-hydroperoxyoctadecadienoic acid in HPLC analyses. This reducing effect was also found in apolipoprotein A-1 (apoA-1). FFA-OOH released from PtdCho-OOH due to PAF-AH activity in oxidized LDL undergo two-electron reduction by the reducing ability of apoA1 in HDL. This preferential reduction of FFA-OOH may participate in the mechanism of the antioxidant property of HDL.

  10. Quinolinic acid induces oxidative stress in rat brain synaptosomes.

    Science.gov (United States)

    Santamaría, A; Galván-Arzate, S; Lisý, V; Ali, S F; Duhart, H M; Osorio-Rico, L; Ríos, C; St'astný, F

    2001-03-26

    The oxidative action of quinolinic acid (QUIN), and the protective effects of glutathione (GSH), and 2-amino-5-phosphonovaleric acid (APV), were tested in rat brain synaptosomes, Reactive oxygen species (ROS) formation was quantified after the exposure of synaptosomes to increasing concentrations of QUIN (25-500 microM). The potency of QUIN to induce lipid peroxidation (LP) was tested as a regional index of thiobarbituric acid-reactive substances (TBARS) production, and the antioxidant actions of both GSH (50 microM) and APV (250 microM) on QUIN-induced LP were evaluated in synaptosomes prepared from different brain regions. QUIN induced concentration-dependent increases in ROS formation and TBARS in all regions analyzed, but increased production of fluorescent peroxidized lipids only in the striatum and the hippocampus, whereas both GSH and APV decreased this index. These results suggest that the excitotoxic action of QUIN involves regional selectivity in the oxidative status of brain synaptosomes, and may be prevented by substances exhibiting antagonism at the NMDA receptor.

  11. Fabrication of pulsed-laser deposited V-W-Nd mixed-oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Yusuke; Venkatachalam, S.; Kaneko, Yoshikazu [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan); Kanno, Yoshinori [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan)], E-mail: kanno@yamanashi.ac.jp

    2007-11-15

    V-W-Nd mixed-oxide films were prepared by pulse-laser deposition (PLD) technique from the targets sintered at different temperatures. X-ray photoelectron spectroscopy (XPS) data indicate that the films fabricated from the targets sintered at low temperature were composed of various mixed valences. Raman spectroscopy shows that V-W-Nd films were composed of the vanadates as NdVO{sub 4}, and the W{sup 6+} doping supplements the formation of vanadate. Atomic force microscopy (AFM) image of the films fabricated from the target sintered at 923 K reveals the average particle size is estimated around 86 nm. The surface morphology of the films roughness shows a dramatic change at 923-943 K.

  12. Corrosion of Bronzes by Extended Wetting with Single versus Mixed Acidic Pollutants

    Directory of Open Access Journals (Sweden)

    Liliana Gianni

    2014-04-01

    Full Text Available The corrosion of bronzes was examined in the context of single-acid versus mixed-acid (as in urban acid rain solutions. Two bi-component bronzes (copper with either 3% Sn or 7% Sn that closely represent those of historic artifacts were immersed for five weeks in conditions designed to replicate those experienced by statues and ornaments in cities where rainfall and humidity constantly produce an electrolyte layer on the surfaces of bronzes. Ions, acids, and particles of pollutants can dissolve in this layer, resulting in a variety of harsh corrosion processes. The kinetics of corrosion and the properties of the resulting patinas were monitored weekly by electrochemical impedance spectroscopy and open-circuit potential measurements. The sizes and appearances of the corrosion products were monitored and used to estimate the progress of the corrosion, whose crystalline structures were visualized using scanning electron microscopy with energy dispersive spectroscopy, identified by X-ray diffraction, and characterized by spectrocolorimetry. The electrochemical measurements demonstrated that greater damage (in terms of color change and corrosion product formation did not correspond to deficiencies in protection. The mixed-acid solution did not corrode the bronzes, as would be expected from the additive effects of the single acids. The postulated mechanisms of metal dissolution appear to be specific to a particular bronze alloy, with the tin component playing an important role.

  13. Fatty acids and oxidative stress in psychiatric disorders

    Directory of Open Access Journals (Sweden)

    Tonello Lucio

    2008-04-01

    Full Text Available Abstract Background The aim of this study was to determine whether there is published evidence for increased oxidative stress in neuropsychiatric disorders. Methods A PubMed search was carried out using the MeSH search term 'oxidative stress' in conjunction with each of the DSM-IV-TR diagnostic categories of the American Psychiatric Association in order to identify potential studies. Results There was published evidence of increased oxidative stress in the following DSM-IV-TR diagnostic categories: mental retardation; autistic disorder; Rett's disorder; attention-deficit hyperactivity disorder; delirium; dementia; amnestic disorders; alcohol-related disorders; amphetamine (or amphetamine-like-related disorders; hallucinogen-related disorders; nicotine-related disorders; opioid-related disorders; schizophrenia and other psychotic disorders; mood disorders; anxiety disorders; sexual dysfunctions; eating disorders; and sleep disorders. Conclusion Most psychiatric disorders are associated with increased oxidative stress. Patients suffering from that subgroup of these psychiatric disorders in which there is increased lipid peroxidation might therefore benefit from fatty acid supplementation (preferably with the inclusion of an antioxidant-rich diet while patients suffering from all these psychiatric disorders might benefit from a change to a whole-food plant-based diet devoid of refined carbohydrate products.

  14. Phosphonic Acids for Interfacial Engineering of Transparent Conductive Oxides

    KAUST Repository

    Paniagua, Sergio A.

    2016-05-26

    Transparent conducting oxides (TCOs), such as indium tin oxide and zinc oxide, play an important role as electrode materials in organic-semiconductor devices. The properties of the inorganic-organic interface - the offset between the TCO Fermi level and the relevant transport level, the extent to which the organic semiconductor can wet the oxide surface, and the influence of the surface on semiconductor morphology - significantly affect device performance. This review surveys the literature on TCO modification with phosphonic acids (PAs), which has increasingly been used to engineer these interfacial properties. The first part outlines the relevance of TCO surface modification to organic electronics, surveys methods for the synthesis of PAs, discusses the modes by which they can bind to TCO surfaces, and compares PAs to alternative organic surface modifiers. The next section discusses methods of PA monolayer deposition, the kinetics of monolayer formation, and structural evidence regarding molecular orientation on TCOs. The next sections discuss TCO work-function modification using PAs, tuning of TCO surface energy using PAs, and initiation of polymerizations from TCO-tethered PAs. Finally, studies that examine the use of PA-modified TCOs in organic light-emitting diodes and organic photovoltaics are compared. © 2016 American Chemical Society.

  15. Production of Caproic Acid from Mixed Organic Waste: An Environmental Life Cycle Perspective.

    Science.gov (United States)

    Chen, Wei-Shan; Strik, David P B T B; Buisman, Cees J N; Kroeze, Carolien

    2017-06-20

    Caproic acid is an emerging platform chemical with diverse applications. Recently, a novel biorefinery process, that is, chain elongation, was developed to convert mixed organic waste and ethanol into renewable caproic acids. In the coming years, this process may become commercialized, and continuing to improve on the basis of numerous ongoing technological and microbiological studies. This study aims to analyze the environmental performance of caproic acid production from mixed organic waste via chain elongation at this current, early stage of technological development. To this end, a life cycle assessment (LCA) was performed to evaluate the environmental impact of producing 1 kg caproic acid from organic waste via chain elongation, in both a lab-scale and a pilot-scale system. Two mixed organic waste were used as substrates: the organic fraction of municipal solid waste (OFMSW) and supermarket food waste (SFW). Ethanol use was found to be the dominant cause of environmental impact over the life cycle. Extraction solvent recovery was found to be a crucial uncertainty that may have a substantial influence on the life-cycle impacts. We recommend that future research and industrial producers focus on the reduction of ethanol use in chain elongation and improve the recovery efficiency of the extraction solvent.

  16. Production of Caproic Acid from Mixed Organic Waste: An Environmental Life Cycle Perspective

    Science.gov (United States)

    2017-01-01

    Caproic acid is an emerging platform chemical with diverse applications. Recently, a novel biorefinery process, that is, chain elongation, was developed to convert mixed organic waste and ethanol into renewable caproic acids. In the coming years, this process may become commercialized, and continuing to improve on the basis of numerous ongoing technological and microbiological studies. This study aims to analyze the environmental performance of caproic acid production from mixed organic waste via chain elongation at this current, early stage of technological development. To this end, a life cycle assessment (LCA) was performed to evaluate the environmental impact of producing 1 kg caproic acid from organic waste via chain elongation, in both a lab-scale and a pilot-scale system. Two mixed organic waste were used as substrates: the organic fraction of municipal solid waste (OFMSW) and supermarket food waste (SFW). Ethanol use was found to be the dominant cause of environmental impact over the life cycle. Extraction solvent recovery was found to be a crucial uncertainty that may have a substantial influence on the life-cycle impacts. We recommend that future research and industrial producers focus on the reduction of ethanol use in chain elongation and improve the recovery efficiency of the extraction solvent. PMID:28513150

  17. Application of Ni-Oxide@TiO2 Core-Shell Structures to Photocatalytic Mixed Dye Degradation, CO Oxidation, and Supercapacitors

    OpenAIRE

    Seungwon Lee; Jisuk Lee; Kyusuk Nam; Weon Gyu Shin; Youngku Sohn

    2016-01-01

    Performing diverse application tests on synthesized metal oxides is critical for identifying suitable application areas based on the material performances. In the present study, Ni-oxide@TiO2 core-shell materials were synthesized and applied to photocatalytic mixed dye (methyl orange + rhodamine + methylene blue) degradation under ultraviolet (UV) and visible lights, CO oxidation, and supercapacitors. Their physicochemical properties were examined by field-emission scanning electron microscop...

  18. Oxidation of cumene in an aprotic medium in the presence of ascorbic acid

    Science.gov (United States)

    Smirnova, O. V.; Efimova, I. V.; Opeida, I. A.

    2015-06-01

    The process of the initiated oxidation of cumene (IPB) with oxygen under homophase conditions in the presence of ascorbic acid (AA) used over a wide range of concentrations is studied. It is shown that in this system, ascorbic acid is consumed in two ways: the auto-oxidation and the inhibition of the oxidation of cumene. The amount of ascorbic acid that participates in inhibiting the oxidation of cumene falls from 28.5 to 16.6% with a rise in the concentration of ascorbic acid in the range of 0.003-0.3 mol/L. The contribution from the rate of the oxidation of ascorbic acid to the total rate of the oxidation of the IPB-AA-DMSO-AIBN system grows from 67.2 to 92.5% with a rise in the concentration of ascorbic acid in the range of 0.01-0.3 mol/L. It is established that the most effective inhibition of the oxidation of cumene with ascorbic acid in aprotic media occurs at concentrations of ascorbic acid of up to 0.01 mol/L. A scheme for the initiated radical-chain oxidation of cumene with ascorbic acid in the aprotic medium that considers the inhibition of the oxidation of cumene with ascorbic acid and the auto-oxidation of ascorbic acid is proposed.

  19. Catalytic activity of titania zirconia mixed oxide catalyst for dimerization eugenol

    Science.gov (United States)

    Tursiloadi, S.; Kristiani, A.; Jenie, S. N. Aisyiyah; Laksmono, J. A.

    2017-01-01

    Clove oil has been found to possess antibacterial, antifungal, antiviral, antitumor, antioxidant and insecticidal properties. The major compound of clove oil is eugenol about 49-87%. Eugenol as phenolic compounds exhibits antioxidant and antimicrobial activities. The derivative compound of eugenol, dieugenol, show antioxidant potency better than parent eugenol. A series of TiO2-ZrO2 mixed oxides (TZ) with various titanium contents from 0 to 100wt%, prepared by using sol gel method were tested their catalytic activity for dimerization eugenol, Their catalytic activity show that these catalysts resulted a low yield of dimer eugenol, dieugenol, about 2-9 % and the purity is more than 50%.

  20. Tunable catalytic properties of bi-functional mixed oxides in ethanol conversion to high value compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Karthikeyan K.; Gray, Michel J.; Job, Heather M.; Smith, Colin D.; Wang, Yong

    2016-04-10

    tA highly versatile ethanol conversion process to selectively generate high value compounds is pre-sented here. By changing the reaction temperature, ethanol can be selectively converted to >C2alcohols/oxygenates or phenolic compounds over hydrotalcite derived bi-functional MgO–Al2O3cata-lyst via complex cascade mechanism. Reaction temperature plays a role in whether aldol condensationor the acetone formation is the path taken in changing the product composition. This article containsthe catalytic activity comparison between the mono-functional and physical mixture counterpart to thehydrotalcite derived mixed oxides and the detailed discussion on the reaction mechanisms.

  1. Single-crystalline Pd square nanoplates enclosed by {100} facets on reduced graphene oxide for formic acid electro-oxidation.

    Science.gov (United States)

    Jiang, Yi; Yan, Yucong; Chen, Wenlong; Khan, Yousaf; Wu, Jianbo; Zhang, Hui; Yang, Deren

    2016-12-06

    Single-crystalline Pd square nanoplates enclosed by {100} facets were generated on reduced graphene oxide and exhibited the substantially enhanced properties for the formic acid oxidation reaction. The combination of carbonyl groups formed on the surface of annealed graphene oxide and Br(-) ions played important roles in this synthesis.

  2. Electro-oxidation of methanol and formic acid on platinum nanoparticles with different oxidation levels

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Chien-Te, E-mail: cthsieh@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China); Hsiao, Han-Tsung; Tzou, Dong-Ying; Yu, Po-Yuan [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan (China); Chen, Po-Yen; Jang, Bi-Sheng [Materials and Electro-Optics Research Division, National Chung-Shan Institute of Science and Technology, Taoyuan 325, Taiwan (China)

    2015-01-15

    Herein reported is an atomic layer deposition (ALD) process of platinum (Pt) from (methylcyclopentadienyl) trimethylplatinum (MeCpPtMe{sub 3}) and oxygen (O{sub 2}) for synthesizing the Pt electrocatalysts toward methanol and formic acid oxidation. The as-synthesized Pt catalysts are thermally reduced in 5 vol% H{sub 2} within temperature window of 150–450 °C. The reduction treatment induces a decrease in amount of Pt oxide (Pt–O) species, e.g., PtO and PtO{sub 2}. The presence of Pt–O species not only enhances catalytic activity but also improves anti-poisoning ability toward the oxidation of methanol and formic acid. The improved activity originates from the fact that the Pt–O species, formed by the ALD route, creates a large number of active sites (e.g., Pt–O{sub ads} and Pt–(OH){sub ads}) to strip the CO-adsorbed sites, leading to a high-level of CO tolerance. This work also proposes a stepwise reaction steps to shed some lights on how the Pt–O species promote the catalytic activity. - Highlights: • This study adopts atomic layer deposition (ALD) to grow metallic Pt nanoparticles. • The Pt catalysts show catalytic activity toward methanol and formic acid oxidation. • The reduction treatment induces a decrease in amount of Pt oxide (Pt–O) species. • The Pt–O species creates a number of active sites to strip the CO-adsorbed sites. • A stepwise reaction step concerning the promoted catalytic activity is proposed.

  3. Iron photoreduction and oxidation in an acidic mountain stream.

    Science.gov (United States)

    McKnight, D M; Kimball, B A; Bencala, K E

    1988-04-29

    In a small mountain stream in Colorado that receives acidic mine drainage, photoreduction of ferric iron results in a well-defined increase in dissolved ferrous iron during the day. To quantify this process, an instream injection of a conservative tracer was used to measure discharge at the time that each sample was collected. Daytime production of ferrous iron by photoreduction was almost four times as great as nighttime oxidation of ferrous iron. The photoreduction process probably involves dissolved or colloidal ferric iron species and limited interaction with organic species because concentrations of organic carbon are low in this stream.

  4. Mitochondrial fatty acid oxidation defects--remaining challenges

    DEFF Research Database (Denmark)

    Gregersen, Niels; Andresen, Brage S; Pedersen, Christina B;

    2008-01-01

    Mitochondrial fatty acid oxidation defects have been recognized since the early 1970s. The discovery rate has been rather constant, with 3-4 'new' disorders identified every decade and with the most recent example, ACAD9 deficiency, reported in 2007. In this presentation we will focus on three...... of different mitochondrial dehydrogenases as well as deficiency of FAD and coenzyme Q(10). With SCAD deficiency, the challenge is to elucidate whether ACADS gene variations are disease-associated, especially when combined with other genetic/cellular/environmental factors, which may act synergistically....

  5. Silica-based composite and mixed-oxide nanoparticles from atmospheric pressure flame synthesis

    Science.gov (United States)

    Akurati, Kranthi K.; Dittmann, Rainer; Vital, Andri; Klotz, Ulrich; Hug, Paul; Graule, Thomas; Winterer, Markus

    2006-08-01

    Binary TiO2/SiO2 and SnO2/SiO2 nanoparticles have been synthesized by feeding evaporated precursor mixtures into an atmospheric pressure diffusion flame. Particles with controlled Si:Ti and Si:Sn ratios were produced at various flow rates of oxygen and the resulting powders were characterized by BET (Brunauer-Emmett-Teller) surface area analysis, XRD, TEM and Raman spectroscopy. In the Si-O-Ti system, mixed oxide composite particles exhibiting anatase segregation formed when the Si:Ti ratio exceeded 9.8:1, while at lower concentrations only mixed oxide single phase particles were found. Arrangement of the species and phases within the particles correspond to an intermediate equilibrium state at elevated temperature. This can be explained by rapid quenching of the particles in the flame and is in accordance with liquid phase solubility data of Ti in SiO2. In contrast, only composite particles formed in the Sn-O-Si system, with SnO2 nanoparticles predominantly found adhering to the surface of SiO2 substrate nanoparticles. Differences in the arrangement of phases and constituents within the particles were observed at constant precursor mixture concentration and the size of the resultant segregated phase was influenced by varying the flow rate of the oxidant. The above effect is due to the variation of the residence time and quenching rate experienced by the binary oxide nanoparticles when varying the oxygen flow rate and shows the flexibility of diffusion flame aerosol reactors.

  6. Effects of phenformin and alpha-bromopalmitate on fatty acid and glucose oxidation in muscle.

    Science.gov (United States)

    Tutwiler, G F

    1978-03-01

    Hemidiaphragms removed from fasted rats which were treated with the fatty acid oxidation inhibitor, alpha-bromopalmitate (125-250 mg/kg, i.p.) oxidized less glucose to CO2 than vehicle-treated rats. Hypoglycemia was noted and was preceded by reduction of muscle palmitate oxidation and by increased plasma free fatty acids (FFA). However, phenformin (100 mg/kg, i.p.) lowered plasma FFA and diaphragm oxidation of both palmitic acid and glucose, without altering glucose levels. These results fail to support the hypothesis that phenformin lowers blood glucose secondary to inhibiton of fatty acid oxidation.

  7. Modeling of thermo-mechanical and irradiation behavior of mixed oxide fuel for sodium fast reactors

    Science.gov (United States)

    Karahan, Aydın; Buongiorno, Jacopo

    2010-01-01

    An engineering code to model the irradiation behavior of UO2-PuO2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named fuel engineering and structural analysis tool (FEAST-OXIDE). FEAST-OXIDE has several modules working in coupled form with an explicit numerical algorithm. These modules describe: (1) fission gas release and swelling, (2) fuel chemistry and restructuring, (3) temperature distribution, (4) fuel-clad chemical interaction and (5) fuel-clad mechanical analysis. Given the fuel pin geometry, composition and irradiation history, FEAST-OXIDE can analyze fuel and cladding thermo-mechanical behavior at both steady-state and design-basis transient scenarios. The code was written in FORTRAN-90 program language. The mechanical analysis module implements the LIFE algorithm. Fission gas release and swelling behavior is described by the OGRES and NEFIG models. However, the original OGRES model has been extended to include the effects of joint oxide gain (JOG) formation on fission gas release and swelling. A detailed fuel chemistry model has been included to describe the cesium radial migration and JOG formation, oxygen and plutonium radial distribution and the axial migration of cesium. The fuel restructuring model includes the effects of as-fabricated porosity migration, irradiation-induced fuel densification, grain growth, hot pressing and fuel cracking and relocation. Finally, a kinetics model is included to predict the clad wastage formation. FEAST-OXIDE predictions have been compared to the available FFTF, EBR-II and JOYO databases, as well as the LIFE-4 code predictions. The agreement was found to be satisfactory for steady-state and slow-ramp over-power accidents.

  8. Oxidized Fatty Acids as Inter-Kingdom Signaling Molecules

    Directory of Open Access Journals (Sweden)

    Carolina H. Pohl

    2014-01-01

    Full Text Available Oxylipins or oxidized fatty acids are a group of molecules found to play a role in signaling in many different cell types. These fatty acid derivatives have ancient evolutionary origins as signaling molecules and are ideal candidates for inter-kingdom communication. This review discusses examples of the ability of organisms from different kingdoms to “listen” and respond to oxylipin signals during interactions. The interactions that will be looked at are signaling between animals and plants; between animals and fungi; between animals and bacteria and between plants and fungi. This will aid in understanding these interactions, which often have implications in ecology, agriculture as well as human and animal health.

  9. Hepatic fatty acid oxidation : activity, localization and function of some enzymes involved

    NARCIS (Netherlands)

    A. van Tol (Arie)

    1971-01-01

    textabstractFatty acid oxidation is an important pathway for energy production in mammals and birds. In animal tissues the enzymes of fatty acid oxidation are located in the mitochondrion. Recent reports suggest that this is not the case in Castor bean endosperm. In this tissue the enzymes of B-oxid

  10. Hepatic fatty acid oxidation : activity, localization and function of some enzymes involved

    NARCIS (Netherlands)

    A. van Tol (Arie)

    1971-01-01

    textabstractFatty acid oxidation is an important pathway for energy production in mammals and birds. In animal tissues the enzymes of fatty acid oxidation are located in the mitochondrion. Recent reports suggest that this is not the case in Castor bean endosperm. In this tissue the enzymes of B-oxid

  11. Radiolysis of Boric Acid Solutions under Mixed Thermal and Fast Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Im, Heejung; Choi, Ke Chon; Yeon, Jeiwon; Song, Kyuseok; Jung Hoansung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The thermal neutron irradiation of water samples containing neutron absorbers has not been published except for a paper reporting the experimental data obtained at high temperatures. However, irradiation or simulations of water and voluminous liquid samples with fast neutrons and gamma rays are frequently discussed in several published papers. Several water samples containing {sup 10}B-enriched boric acid, and natural and {sup 10}B-enriched mixed boric acids in the range of 0 to 2000 μg/mL for the function of {sup 10}B concentration, were irradiated to study the radiolysis of the cooling water containing boric acid. The concentration of natural boron in the primary coolant of pressurized water reactors (PWRs) is known to start at 1500 μg/mL, and boric acid is used for the purpose of nuclear reaction control.

  12. Structural characterization of mixed uranium-plutonium co-precipitates and oxides synthesized by oxalic co-conversion route

    Energy Technology Data Exchange (ETDEWEB)

    Arab-Chapelet, B.; De Bruycker, F.; Picart, S.; Leturcq, G.; Grandjean, S. [Laboratoire de Chimie des Actinides, CEA Valrho, bat 399, BP17171, 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    In this study, mixed uranium(IV)-plutonium(III) oxalate co-precipitates with Pu/(U+Pu) molar ratio equal to 29 and 45% were synthesized and characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). The thermal conversion step of these co-precipitates into oxide was carried out under argon flow up to 700 deg. C leading to mixed oxides. The structural investigation on these oxides indicates the formation of (U,Pu)O{sub 2} fluorite-type solid solution characterized by a very homogeneous distribution of plutonium and uranium, a controlled oxygen stoichiometry and well-defined morphology of particles. (authors)

  13. Mitochondrial fatty acid oxidation alterations in heart failure, ischaemic heart disease and diabetic cardiomyopathy.

    Science.gov (United States)

    Fillmore, N; Mori, J; Lopaschuk, G D

    2014-04-01

    Heart disease is a leading cause of death worldwide. In many forms of heart disease, including heart failure, ischaemic heart disease and diabetic cardiomyopathies, changes in cardiac mitochondrial energy metabolism contribute to contractile dysfunction and to a decrease in cardiac efficiency. Specific metabolic changes include a relative increase in cardiac fatty acid oxidation rates and an uncoupling of glycolysis from glucose oxidation. In heart failure, overall mitochondrial oxidative metabolism can be impaired while, in ischaemic heart disease, energy production is impaired due to a limitation of oxygen supply. In both of these conditions, residual mitochondrial fatty acid oxidation dominates over mitochondrial glucose oxidation. In diabetes, the ratio of cardiac fatty acid oxidation to glucose oxidation also increases, although primarily due to an increase in fatty acid oxidation and an inhibition of glucose oxidation. Recent evidence suggests that therapeutically regulating cardiac energy metabolism by reducing fatty acid oxidation and/or increasing glucose oxidation can improve cardiac function of the ischaemic heart, the failing heart and in diabetic cardiomyopathies. In this article, we review the cardiac mitochondrial energy metabolic changes that occur in these forms of heart disease, what role alterations in mitochondrial fatty acid oxidation have in contributing to cardiac dysfunction and the potential for targeting fatty acid oxidation to treat these forms of heart disease.

  14. ANTIOXIDANT AND PRO-OXIDANT EFFECT OF ASCORBIC ACID

    Directory of Open Access Journals (Sweden)

    Goran Rankovic

    2005-01-01

    Full Text Available Free radicals attack proteins, lipids, enzymes and DNA causing pathological changes in organism. There are many mechanisms that organism uses to fight against free radicals. Ascorbic acid is one of the strongest reducers and eliminators of free radicals. It reduces stable oxygenic, azoth and thyol radicals and acts as a primary defense against water radicals in blood. When radicals are dissolved in water suspensions of erythrocytes and low density lipoproteins (LDL, ascorbic acid catches and eliminates free radicals before they arrive to the membrane and LDL molecules. Even though ascorbic acid is not capable of eliminating free radicals out of fluid medium, it acts as synergist to alpha-tocopherol in lipid section, contributes to the lessening of lipid tocoperoxil radicals, and above all, regenerates alpha-tocopherol. Ascorbic acid may act as pro-oxidant under in vitro conditions in the presence of metals; however, this effect is probably not important under in vivo conditions where metal ions, being sequestered, become second reducers.

  15. Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

    OpenAIRE

    2014-01-01

    The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution...

  16. Ammonia-oxidizing archaea have more important role than ammonia-oxidizing bacteria in ammonia oxidation of strongly acidic soils.

    Science.gov (United States)

    Zhang, Li-Mei; Hu, Hang-Wei; Shen, Ju-Pei; He, Ji-Zheng

    2012-05-01

    Increasing evidence demonstrated the involvement of ammonia-oxidizing archaea (AOA) in the global nitrogen cycle, but the relative contributions of AOA and ammonia-oxidizing bacteria (AOB) to ammonia oxidation are still in debate. Previous studies suggest that AOA would be more adapted to ammonia-limited oligotrophic conditions, which seems to be favored by protonation of ammonia, turning into ammonium in low-pH environments. Here, we investigated the autotrophic nitrification activity of AOA and AOB in five strongly acidic soils (pHnitrification inhibitor dicyandiamide (DCD) completely inhibited the nitrification activity and CO(2) fixation by AOA, accompanied by decreasing thaumarchaeal amoA gene abundance. Bacterial amoA gene abundance decreased in all microcosms irrespective of DCD addition, and mostly showed no correlation with nitrate concentrations. Phylogenetic analysis of thaumarchaeal amoA gene and 16S rRNA gene revealed active (13)CO(2)-labeled AOA belonged to groups 1.1a-associated and 1.1b. Taken together, these results provided strong evidence that AOA have a more important role than AOB in autotrophic ammonia oxidation in strongly acidic soils.

  17. The suppression of enhanced bitterness intensity of macrolide dry syrup mixed with an acidic powder.

    Science.gov (United States)

    Ishizaka, Toshihiko; Okada, Sachie; Takemoto, Eri; Tokuyama, Emi; Tsuji, Eriko; Mukai, Junji; Uchida, Takahiro

    2007-10-01

    The aim of the present study was to identify a medicine which strongly enhanced the bitterness of clarithromycin dry syrup (CAMD) when administered concomitantly and to develop a method to suppress this enhanced bitterness. The bitterness enhancement was evaluated not only by gustatory sensation tests but also using pH and taste sensor measurements of the mixed sample. A remarkable bitterness enhancement was found when CAMD was mixed with the acidic powder L-carbocysteine. The acidic pH (pH 3.40) of the suspension made from these two preparations, seemed to be due to enhanced release of clarithromycin caused by the dissolution of the alkaline polymer film-coating. Several methods for preventing this bitterness enhancement were investigated. Neither increasing the volume of water taken with the mixture, nor changing the ratio of CAMD:L-carbocysteine in the mixture, were effective in reducing the bitterness intensity of the CAMD/L-carbocysteine mixture. The best way to achieve taste masking was to first administer CAMD mixed with chocolate jelly, which has a neutral pH, followed by the L-carbocysteine suspension. Similar results were obtained for the bitterness suppression of azithromycin fine granules with L-carbocysteine. The chocolate jelly will be useful for taste masking of bitter macrolide drug formulations, when they need to be administered together with acidic drug formulations.

  18. Thermodynamics of mixed-ligand complex formation of mercury (II) ethylenediaminetetraacetate with amino acids in solution

    Energy Technology Data Exchange (ETDEWEB)

    Pyreu, Dmitrii, E-mail: pyreu@mail.ru [Department of Inorganic and Analytic Chemistry, Ivanovo State University, Ermak 39, Ivanovo 153025 (Russian Federation); Kozlovskii, Eugenii [Department of Inorganic and Analytic Chemistry, Ivanovo State University, Ermak 39, Ivanovo 153025 (Russian Federation); Gruzdev, Matvei; Kumeev, Roman [Institute of Solution Chemistry, Ivanovo (Russian Federation)

    2012-11-20

    Highlights: Black-Right-Pointing-Pointer Stable mixed ligand complexes of HgEdta with amino acids at physiological pH value. Black-Right-Pointing-Pointer The thermodynamic and NMR data evident the ambidentate coordination mode of arginine. Black-Right-Pointing-Pointer Participation of the guanidinic group of Arg in coordination process. Black-Right-Pointing-Pointer Binuclear complexes (HgEdta){sub 2}L with the bridging function of amino acid. - Abstract: The mixed-ligand complex formation in the systems Hg{sup 2+} - Edta{sup 4-} - L{sup -}(L = Arg, Orn, Ser) has been studied by means of calorimetry, pH-potentiometry and NMR spectroscopy in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO{sub 3}). The thermodynamic parameters of formation of the HgEdtaL, HgEdtaHL and (HgEdta){sub 2}L complexes have been determined. The most probable coordination mode for the complexone and the amino acid in the mixed-ligand complexes was discussed.

  19. Ruthenium-catalyzed aerobic oxidative decarboxylation of amino acids: a green, zero-waste route to biobased nitriles.

    Science.gov (United States)

    Claes, Laurens; Verduyckt, Jasper; Stassen, Ivo; Lagrain, Bert; De Vos, Dirk E

    2015-04-18

    Oxidative decarboxylation of amino acids into nitriles was performed using molecular oxygen as terminal oxidant and a heterogeneous ruthenium hydroxide-based catalyst. A range of amino acids was oxidized in very good yield, using water as the solvent.

  20. Preparation and Characterization of Novel Choline and L-Glutamic Acid Mixed Monolayer Covalently Modified Glassy Carbon Electrode and Its Analytical Application to Nitrite Determination

    Institute of Scientific and Technical Information of China (English)

    晋冠平; 林祥钦

    2005-01-01

    A choline and L-glutamic acid mixed monolayer covalently modified glassy carbon electrode (Ch-Glu/GCE) was fabricated and characterized by X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). It provided an excellent example of mixed covalent monolayer modification of carbon electrodes with alkanol and amino acid, and also a facile means for altering the interfacial architecture. The Ch-Glu/GCE displayed good catalytic activity toward the oxidation of nitrite anions. Differential pulse voltammetry was used for determination of nitrite at the Ch-Glu/GCE. The Ch-Glu/GCE showed higher capability for restraint of pollutions than a simple Ch modified electrode or a simple Glu modified electrode.

  1. Cyanide-insensitive and clofibrate enhanced beta-oxidation of dodecanedioic acid in rat liver. An indication of peroxisomal beta-oxidation of N-dicarboxylic acids.

    Science.gov (United States)

    Mortensen, P B; Kølvraa, S; Gregersen, N; Rasmussen, K

    1982-11-12

    The beta-oxidation rate of dodecanedioic acid in rat liver homogenates (600 X g supernatant fraction) was determined by simultaneous measurements of the C6-C12-dicarboxylic acids, i.e., adipic, suberic, sebacic and dodecanedioic acids, in relation to time in assays incubated with dodecanedioic acid. Measurements were performed by a combined gas chromatographic-mass spectrometric technique, i.e., selected ion-monitoring. The beta-oxidation rate was registered as the consumption rate of dodecanedioic acid and as the initial rise in the concentrations of C6-C10-dicarboxylic acids. The beta-oxidation rate of C8-C12-dicarboxylic acids was increased many times in homogenates from clofibrate-treated rats. Moreover, it was unexpectedly found that 2.0 mM cyanide was unable to inhibit the beta-oxidation rate of the dicarboxylic acids in vitro, but in fact caused a minor increase in the rate of beta-oxidation in homogenates from both normal and clofibrate-treated rats. It was concluded that the present results strongly indicate the existence of a peroxisomal beta-oxidation of dicarboxylic acids.

  2. Lewis acid catalysis and Green oxidations: sequential tandem oxidation processes induced by Mn-hyperaccumulating plants.

    Science.gov (United States)

    Escande, Vincent; Renard, Brice-Loïc; Grison, Claude

    2015-04-01

    Among the phytotechnologies used for the reclamation of degraded mining sites, phytoextraction aims to diminish the concentration of polluting elements in contaminated soils. However, the biomass resulting from the phytoextraction processes (highly enriched in polluting elements) is too often considered as a problematic waste. The manganese-enriched biomass derived from native Mn-hyperaccumulating plants of New Caledonia was presented here as a valuable source of metallic elements of high interest in chemical catalysis. The preparation of the catalyst Eco-Mn1 and reagent Eco-Mn2 derived from Grevillea exul exul and Grevillea exul rubiginosa was investigated. Their unusual polymetallic compositions allowed to explore new reactivity of low oxidative state of manganese-Mn(II) for Eco-Mn1 and Mn(IV) for Eco-Mn2. Eco-Mn1 was used as a Lewis acid to catalyze the acetalization/elimination of aldehydes into enol ethers with high yields; a new green and stereoselective synthesis of (-)-isopulegol via the carbonyl-ene cyclization of (+)-citronellal was also performed with Eco-Mn1. Eco-Mn2 was used as a mild oxidative reagent and controlled the oxidation of aliphatic alcohols into aldehydes with quantitative yields. Oxidative cleavage was interestingly noticed when Eco-Mn2 was used in the presence of a polyol. Eco-Mn2 allowed direct oxidative iodination of ketones without using iodine, which is strongly discouraged by new environmental legislations. Finally, the combination of the properties in the Eco-Mn catalysts and reagents gave them an unprecedented potential to perform sequential tandem oxidation processes through new green syntheses of p-cymene from (-)-isopulegol and (+)-citronellal; and a new green synthesis of functionalized pyridines by in situ oxidation of 1,4-dihydropyridines.

  3. Evaluation of Co-precipitation Processes for the Synthesis of Mixed-Oxide Fuel Feedstock Materials

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Emory D [ORNL; Voit, Stewart L [ORNL; Vedder, Raymond James [ORNL

    2011-06-01

    The focus of this report is the evaluation of various co-precipitation processes for use in the synthesis of mixed oxide feedstock powders for the Ceramic Fuels Technology Area within the Fuels Cycle R&D (FCR&D) Program's Advanced Fuels Campaign. The evaluation will include a comparison with standard mechanical mixing of dry powders and as well as other co-conversion methods. The end result will be the down selection of a preferred sequence of co-precipitation process for the preparation of nuclear fuel feedstock materials to be used for comparison with other feedstock preparation methods. A review of the literature was done to identify potential nitrate-to-oxide co-conversion processes which have been applied to mixtures of uranium and plutonium to achieve recycle fuel homogeneity. Recent studies have begun to study the options for co-converting all of the plutonium and neptunium recovered from used nuclear fuels, together with appropriate portions of recovered uranium to produce the desired mixed oxide recycle fuel. The addition of recycled uranium will help reduce the safeguard attractiveness level and improve proliferation resistance of the recycled fuel. The inclusion of neptunium is primarily driven by its chemical similarity to plutonium, thus enabling a simple quick path to recycle. For recycle fuel to thermal-spectrum light water reactors (LWRs), the uranium concentration can be {approx}90% (wt.), and for fast spectrum reactors, the uranium concentration can typically exceed 70% (wt.). However, some of the co-conversion/recycle fuel fabrication processes being developed utilize a two-step process to reach the desired uranium concentration. In these processes, a 50-50 'master-mix' MOX powder is produced by the co-conversion process, and the uranium concentration is adjusted to the desired level for MOX fuel recycle by powder blending (milling) the 'master-mix' with depleted uranium oxide. In general, parameters that must be

  4. Methane oxidation over Fe-, Co-, Ni- and V-containing mixed conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kharton, V.V.; Yaremchenko, A.A.; Tsipis, E.V.; Shaula, A.L.; Frade, J.R. [Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Valente, A.A.; Rocha, J. [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Sobyanin, V.A.; Belyaev, V.D.; Semin, G.L.; Veniaminov, S.A. [Boreskov Institute of Catalysis SB RAS, 5 pr. Akademika Lavrentieva, Novosibirsk 630090 (Russian Federation)

    2005-02-28

    The catalytic oxidation of methane over mixed conducting ceramics, including perovskite-type SrFe{sub 0.7}Al{sub 0.3}O{sub 3-{delta}} and La{sub 0.3}Sr{sub 0.7}Co{sub 0.8}Ga{sub 0.2}O{sub 3-{delta}}, dual-phase composite (SrCo){sub 0.5}(Sr{sub 2}Fe{sub 3}){sub 0.5}O{sub 4.75+}/-{sub {delta}}, La{sub 2}Ni{sub 0.9}Co{sub 0.1}O{sub 4+{delta}} with K{sub 2}NiF{sub 4}-type structure and zircon-type CeVO{sub 4+{delta}}, is primarily governed by bonding energy between oxygen and transition metal cations, which leads to general correlations between the catalytic activity, oxygen desorption, oxygen ionic transport, thermal expansion, and, often, phase stability. The steady-state conversion of dry CH{sub 4} either by oxygen permeating through dense oxide ceramics in a membrane reactor or by atmospheric O{sub 2} (methane/air ratio of 30:70) in a fixed bed reactor with membrane material as catalyst results in high CO{sub 2} selectivity, increasing when the oxygen permeability of mixed conductors increases. The prevailing mechanism of total methane combustion makes it necessary to incorporate reforming catalysts in the membrane reactors for natural gas conversion to Synthesis gas (syngas). Dominant CO{sub 2} formation is also observed for the oxidation of CH{sub 4} pulses supplied in helium flow over the mixed conductor powders, except for SrFe{sub 0.7}Al{sub 0.3}O{sub 3-{delta}} yielding synthesis gas with the H{sub 2}/CO ratio close to 2, characteristic of the partial oxidation process. For a model reactor comprising one disk-shaped membrane and a catalyst both made of SrFe{sub 0.7}Al{sub 0.3}O{sub 3-{delta}}, the methane conversion and CO selectivity at 1223 K achieved 65% and 48%, respectively.

  5. Study of sodium dodecyl sulfate-poly(propylene oxide) methacrylate mixed micelles.

    Science.gov (United States)

    Bastiat, Guillaume; Grassl, Bruno; Khoukh, Abdel; François, Jeanne

    2004-07-01

    Sodium dodecyl sulfate (SDS)-poly(propylene oxide) methacrylate (PPOMA) (of molecular weight M(w) = 434 g x mol(-1)) mixtures have been studied using conductimetry, static light scattering, fluorescence spectroscopy, and 1H NMR. It has been shown that SDS and PPOMA form mixed micelles, and SDS and PPOMA aggregation numbers, N(ag SDS) and N(ag PPOMA), have been determined. Total aggregation numbers of the micelles (N(ag SDS) + N(ag PPOMA)) and those of SDS decrease upon increasing the weight ratio R = PPOMA/SDS. Localization of PPOMA inside the mixed micelles is considered (i) using 1H NMR to localize the methacrylate function at the hydrophobic core-water interface and (ii) by studying the SDS-PPO micellar system (whose M(w) = 400 g x mol(-1)). Both methods have indicated that the PPO chain of the macromonomer is localized at the SDS micelle surface. Models based on the theorical prediction of the critical micellar concentration of mixed micelles and structural model of swollen micelles are used to confirm the particular structure proposed for the SDS-PPOMA system, i.e., the micelle hydrophobic core is primarily composed of the C12 chains of the sodium dodecyl sulfate, the hydrophobic core-water interface is made up of the SDS polar heads as well as methacrylate functions of the PPOMA, the PPO chains of the macromonomer are adsorbed preferentially on the surface, i.e., on the polar heads of the SDS.

  6. Dynamics of nitrogen oxides and ozone above and within a mixed hardwood forest in northern Michigan

    Directory of Open Access Journals (Sweden)

    B. Seok

    2013-08-01

    Full Text Available The dynamic behavior of nitrogen oxides (NOx = NO + NO2 and ozone (O3 above and within the canopy at the University of Michigan Biological Station AmeriFlux (UMBS Flux site was investigated by continuous multi-height vertical gradient measurements during the summer and the fall of 2008. A daily maximum in nitric oxide (NO mixing ratios was consistently observed during the morning hours between 06:00 and 09:00 EST above the canopy. Daily NO maxima ranged between 0.1 and 2 ppbv (with a median of 0.3 ppbv, which were 2 to 20 times above the atmospheric background. The sources and causes of the morning NO maximum were evaluated using NOx and O3 measurements and synoptic and micrometeorological data. Numerical simulations with a multi-layer canopy-exchange model were done to further support this analysis. The observations indicated that the morning NO maximum was caused by the photolysis of NO2 from non-local air masses, which were transported into the canopy from aloft during the morning breakup of the nocturnal boundary layer. The analysis of simulated process tendencies indicated that the downward turbulent transport of NOx into the canopy compensates for the removal of NOx through chemistry and dry deposition. The sensitivity of NOx and O3 concentrations to soil and foliage NOx emissions was also assessed with the model. Uncertainties associated with the emissions of NOx from the soil or from leaf-surface nitrate photolysis did not explain the observed diurnal behavior in NOx (and O3 and, in particular, the morning peak in NOx mixing ratios. However, a ~30% increase in early morning NOx and NO peak mixing ratios was simulated when a foliage exchange NO2 compensation point was considered. This increase suggests the potential importance of leaf-level, bidirectional exchange of NO2 in understanding the observed temporal variability in NOx at UMBS.

  7. ω-Alkynyl lipid surrogates for polyunsaturated fatty acids: free radical and enzymatic oxidations.

    Science.gov (United States)

    Beavers, William N; Serwa, Remigiusz; Shimozu, Yuki; Tallman, Keri A; Vaught, Melissa; Dalvie, Esha D; Marnett, Lawrence J; Porter, Ned A

    2014-08-13

    Lipid and lipid metabolite profiling are important parameters in understanding the pathogenesis of many diseases. Alkynylated polyunsaturated fatty acids are potentially useful probes for tracking the fate of fatty acid metabolites. The nonenzymatic and enzymatic oxidations of ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were compared to that of linoleic and arachidonic acid. There was no detectable difference in the primary products of nonenzymatic oxidation, which comprised cis,trans-hydroxy fatty acids. Similar hydroxy fatty acid products were formed when ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were reacted with lipoxygenase enzymes that introduce oxygen at different positions in the carbon chains. The rates of oxidation of ω-alkynylated fatty acids were reduced compared to those of the natural fatty acids. Cyclooxygenase-1 and -2 did not oxidize alkynyl linoleic but efficiently oxidized alkynyl arachidonic acid. The products were identified as alkynyl 11-hydroxy-eicosatetraenoic acid, alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid, and alkynyl prostaglandins. This deviation from the metabolic profile of arachidonic acid may limit the utility of alkynyl arachidonic acid in the tracking of cyclooxygenase-based lipid oxidation. The formation of alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid compared to alkynyl prostaglandins suggests that the ω-alkyne group causes a conformational change in the fatty acid bound to the enzyme, which reduces the efficiency of cyclization of dioxalanyl intermediates to endoperoxide intermediates. Overall, ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid appear to be metabolically competent surrogates for tracking the fate of polyunsaturated fatty acids when looking at models involving autoxidation and oxidation by lipoxygenases.

  8. Silver di-t-butyl phosphate, a useful reagent in the synthesis of phospholipids. Synthesis of mixed-acid phosphatidic acid and phosphatidyl glycerolphosphate

    NARCIS (Netherlands)

    Bonsen, P.P.M.; Haas, Gerard H. de

    1967-01-01

    The synthesis of silver di-t-butyl phosphate is described. Using this reagent, mixed-acid phosphatidic acid with one unsaturated fatty acid could be prepared by means of a reaction with a 1,2-diacyl glycerol-3-iodohydrin. The blocking groups could be removed easily with dry hydrogen chloride at low

  9. Electrocatalysis by nanoparticles: Oxidation of formic acid at manganese oxide nanorods-modified Pt planar and nanohole-arrays

    Directory of Open Access Journals (Sweden)

    Mohamed S. El-Deab

    2010-01-01

    Full Text Available The electro-oxidation of formic acid (an essential reaction in direct formic acid fuel cells is a challenging process because of the deactivation of anodes by the adsorption of the poisoning intermediate carbon monoxide (CO. Pt electrodes in two geometries (planar and nanohole-array were modified by the electrodeposition of manganese oxide nanorods (nano-MnOx. The modified Pt electrodes were then tested for their electrocatalytic activity through the electro-oxidation of formic acid in a solution of pH 3.45. Two oxidation peaks (Ipd and Ipind were observed at 0.2 and 0.55 V, respectively; these were assigned to the direct and indirect oxidative pathways. A significant enhancement of the direct oxidation of formic acid to CO2 was observed at the modified electrodes, while the formation of the poisoning intermediate CO was suppressed. Ipd increases with surface coverage (θ of nano-MnOx with a concurrent depression of Ipind. An increase in the ratio Ipd/ν1/2 with decreasing potential scan rate (ν indicates that the oxidation process proceeds via a catalytic mechanism. The modification of Pt anodes with manganese oxide nanorods results in a significant improvement of the electrocatalytic activity along with a higher tolerance to CO. Thus nano-MnOx plays a crucial role as a catalytic mediator which facilitates the charge transfer during the direct oxidation of formic acid to CO2.

  10. A magnetic route to measure the average oxidation state of mixed-valent manganese in manganese oxide octahedral molecular sieves (OMS).

    Science.gov (United States)

    Shen, Xiong-Fei; Ding, Yun-Shuang; Liu, Jia; Han, Zhao-Hui; Budnick, Joseph I; Hines, William A; Suib, Steven L

    2005-05-04

    A magnetic route has been applied for measurement of the average oxidation state (AOS) of mixed-valent manganese in manganese oxide octahedral molecular sieves (OMS). The method gives AOS measurement results in good agreement with titration methods. A maximum analysis deviation error of +/-7% is obtained from 10 sample measurements. The magnetic method is able to (1) confirm the presence of mixed-valent manganese and (2) evaluate AOS and the spin states of d electrons of both single oxidation state and mixed-valent state Mn in manganese oxides. In addition, the magnetic method may be extended to (1) determine AOS of Mn in manganese oxide OMS with dopant "diamagnetic" ions, such as reducible V5+ (3d0) ions, which is inappropriate for the titration method due to interference of redox reactions between these dopant ions and titration reagents, such as KMnO4, (2) evaluate the dopant "paramagnetic" ions that are present as clusters or in the OMS framework, and (3) determine AOS of other mixed-valent/single oxidation state ion systems, such as Mo3+(3d3)-Mo4+(3d2) systems and Fe3+ in FeCl3.

  11. Mixed oxides derived from layered double hydroxides as novel catalysts for phenol photodegradation

    Science.gov (United States)

    Puscasu, C. M.; Carja, G.; Mureseanu, M.; Zaharia, C.

    2017-08-01

    The removal of organic pollutants is nowadays a very challenging aspect of the environmental research. There are strong interests to develop novel semiconducting photocatalysts able to efficiently promote advanced oxidation reactions. The development of photocatalysts based on the mixtures of mixed oxides derived from layered double hydroxides (LDHs) - a family of naturally occurring anionic clays - might offer novel environmental-friendly solutions for the cost effective removal of organic pollutants. This work presents ZnO/ZnAl2O4, ZnO/Zn2TiO4 and ZnO/ZnCr2O4 as novel photocatalytic formulations for phenol degradation under UV irradiation. They were obtained by the controlled thermal treatment of the layered double hydroxides matrices (LDHs), as precursors materials, type ZnM-LDH (M = Al3+, Cr3+ or Ti4+). The LDHs were synthesized by the co-precipitation method at a constant pH. Controlled calcination at 650°C gives rise to solutions of mixed metal oxides. The structural and nanoarchitectonics characteristics of the studied catalysts were described by: XRD, SEM/TEM and TG/DTG techniques. Results show that in the photocatalytic process of the phenol degradation from aqueous solutions, ZnO/ZnCr2O4 and ZnO/ZnAl2O4 showed the best performance degrading ∼98% of phenol after 3.5 hs and 5 hs, respectively; while ZnO/Zn2TiO4 has degraded almost 80 % after 7.5 hs of UV irradiation. These results open new opportunities in the development of new cost effective photoresponsive formulations able to facilitate the photo-degradation of the organic pollution as “green” solution for removal of dangerous pollutants.

  12. Hydration of ordinary portland cements made from raw mix containing transition element oxides

    Energy Technology Data Exchange (ETDEWEB)

    Kakali, G.; Tsivilis, S.; Tsialtas, A. [National Technical Univ. of Athens (Greece)

    1998-03-01

    The use of industrial wastes, such as waste tires, waste oil, non-ferrous metal slag, or waste molding sand, as alternative raw materials and fuel in cement plants has been established from an environmental and recycling point of view and is expected to increase in the future. Cement is broadly used, among other hydraulic binders, in the solidification and stabilization of industrial and municipal wastes. This tendency to the use of wastes in the cement industry or the utilization of cement for the handling of wastes has led to the presence of several transition element compounds in the clinker and/or in the hydrated cement. The subject of this paper is the study of the hydration process in cements made from raw mixes containing transition element oxides. The oxides used are ZrO{sub 2}, V{sub 2}O{sub 5}, Ni{sub 2}O{sub 3}, CuO, Co{sub 2}O{sub 3}, MnO, Cr{sub 2}O{sub 3}, TiO{sub 2}, MoO{sub 3}, and ZnO, and their percentage in the raw mixes is 2% w/w. The cement pastes are cured in water for 24 h, 48 h, 7 days and 28 days. Hydration rate and products are studied by means of X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. As it is concluded, the added oxides provoke, in general, a retardation of the hydration reactions. The effect is stronger during the first 2 days and becomes negligible at 28 days. The addition of CuO strongly delays the hydration even after 28 days. Its action is related to the formation of Cu(OH){sub 2} during the first days of hydration.

  13. Oxidative aromatization of Hantzsch 1,4-dihydropyridines by aqueous hydrogen peroxide-acetic acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simple method for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved by using hydrogen peroxide as green oxidant and acetic acid as catalyst in aqueous solution.

  14. The association between low-grade inflammation, iron status and nucleic acid oxidation in the elderly

    DEFF Research Database (Denmark)

    Broedbaek, Kasper; Siersma, Volkert Dirk; Andersen, Jon T

    2011-01-01

    This study applied a case-control approach to investigate the association between low-grade inflammation, defined by high values within the normal range of C-reactive protein (CRP) and interleukin-6 (IL-6), and urinary markers of nucleic acid oxidation. No differences in excretion of urinary...... markers of nucleic acid oxidation between cases and controls were found and multivariable linear regression analysis showed no association between urinary markers of nucleic acid oxidation and inflammatory markers. Post-hoc multivariable linear regression analysis showed significant associations between...... nucleic acid oxidation and various iron status markers and especially a close relationship between nucleic acid oxidation and ferritin. This study shows no association between low-grade inflammation and urinary markers of nucleic acid oxidation in a population of elderly Italian people. The results...

  15. Measurement of fatty acid oxidation: validation of isotopic equilibrium extrapolation

    Energy Technology Data Exchange (ETDEWEB)

    Robin, A.P.; Jeevanandam, M.; Elwyn, D.H.; Askanazi, J.; Kinney, J.M.

    1989-01-01

    Measurement of whole body substrate oxidation requires prolonged isotope infusion to attain plateau specific activity (SA) of expired CO/sub 2/. We have investigated in 13 hospitalized patients a technique whereby plateau /sup 14/CO/sub 2/ SA is extrapolated using computer curve fitting based upon the early exponential rise. A primed-constant infusion of albumin-bound 1-/sup 14/C-palmitate was continued for 260 minutes with isotope priming of the secondary bicarbonate pool at 70 minutes. Plasma free fatty acid (FFA) SA reached steady state by 40 minutes and was 91% +/- 4% (SE) of values obtained at 190 to 260 minutes. At 70 minutes /sup 14/CO/sub 2/ SA reached only 44% +/- 1% of the 190 to 260 minute values, which were consistently at plateau. The predicted steady state /sup 14/CO/sub 2/ SA from the 40 to 70 minute curves and the FFA oxidation rates calculated from those values were 94% +/- 2% and 102% +/- 4%, respectively, of values measured at steady state (190 to 260 minutes). The relationship between predicted and measured values approximated the line of identity for /sup 14/CO/sub 2/ SA (y = 0.90x + 0.14, r = .98, P less than .001) and FFA oxidation (y = 1.02x, r = .98, P less than .001). The results suggest that FFA oxidation can be accurately calculated using a short infusion of labeled FFA without bicarbonate pool priming, thus avoiding overpriming or underpriming and possibly allowing multiple studies and diminished radioisotope exposure.

  16. Folic acid mediated solid lipid nanocarriers loaded with docetaxel and oxidized single-walled carbon nanotubes

    Science.gov (United States)

    Zhu, Xiali; Huang, Shengnan; Xie, Yingxia; Zhang, Huijuan; Hou, Lin; Zhang, Yingjie; Huang, Heqing; Shi, Jinjin; Wang, Lei; Zhang, Zhenzhong

    2014-01-01

    Single-walled carbon nanotubes (SWNT) possess high-near-infrared absorption coefficient, large surface area, and have great potential in drug delivery. In this study, we obtained ultrashort oxidized SWNT (OSWNT) using mixed acid oxidation method. Then, docetaxel (DTX) and folic acid (FA) are conjugated with OSWNT via π- π accumulation and amide linkage, respectively. A targeting and photothermal sensitive drug delivery system FA-DTX-OSWNT-SLN was prepared following a microemulsion technique. The size and zeta potential of FA-DTX-OSWNT-SLN were 182.8 ± 2.8 nm and -34.59 ± 1.50 mV, respectively. TEM images indicated that FA-DTX-OSWNT-SLN was spherical and much darker than general solid lipid nanoparticles (SLN). Furthermore, OSWNT may wind round, insert into or be encapsulated into the nanocarriers. Compared with free DTX, FA-DTX-OSWNT-SLN could efficiently cross cell membranes and afford higher antitumor efficacy in MCF-7 cells in vitro. Meanwhile, the combination of near-infrared laser (NIR) irradiation at 808 nm significantly enhanced cell inhibition. In conclusion, FA-DTX-OSWNT-SLN drug delivery system in combination with 808 nm NIR laser irradiation may be promising for targeting and photothermal cancer therapy with multiple mechanisms in future.

  17. Reduced graphene oxide/molecular imprinted polymer-organic thin film transistor for amino acid detection

    Science.gov (United States)

    Halim, Nurul Farhanah AB.; Musa, Nur Hazwani; Zakaria, Zulkhairi; Von Schleusingen, Mubaraq; Ahmad, Mohd Noor; Derman, Nazree; Shakaff, Ali Yeon Md.

    2017-03-01

    This works reports the electrical performance of reduced graphene oxide (RGO)/Molecular imprinted polymer (MIP)- organic thin film transistor (OTFT) for amino-acid detection, serine. These biomimetic sensors consider MIP as man-tailored biomimetic recognition sites that play an important role in signal transduction. MIP provides recognition sites compatible with serine molecules was developed by dispersing serine with methylacrylate acid (MAA) as functional monomer and Ethylene glycol dimethylacrylate (EGDMA) as cross-linker. The imprinted polymeric were mixed with reduced graphene oxide to produced sensing layer for the sensor. RGO-MIP layer was introduced between source and drain of OTFT via spin coating as a detecting layer for serine molecules. RGO was introduced into MIP, to allow a highly conductive sensing material thus enhanced selectivity and sensitivity of the sensor. By analyzing the electrical performance of the sensors, the performances of OTFT sensor enhanced with RGO/MIP interlayer and OTFT sensor with MIP interlayer when exposed to serine analyte were obtained. The results showed that there were remarkable shifts of drain current (ID) obtained from OTFT sensor with RGO/MIP interlayer after exposed to serine analyte. Moreover, the sensitivity of OTFT sensor with RGO/MIP interlayer was nearly higher than the OTFT sensor with MIP interlayer. Hence, it proved that RGO successfully enhanced the sensing performance of OTFT sensor.

  18. Spectrophotometric determination of the acidity constants of calcon in water and mixed water–organic solvents

    Directory of Open Access Journals (Sweden)

    MOHAMMAD MAZLOUM-ARDAKANI

    2009-02-01

    Full Text Available The acid–base properties of calcon (1-(2-hydroxy-1-naphthylazo-2-naphthol-4-sulfonic acid in water and mixed water–organic solvents at 25 °C at an ionic strength of 0.10 M are studied by a multiwavelength spectrophotometric method. The organic solvents used were the amphiprotic (methanol, dipolar aprotic (dimethylsulfoxide, and low basic aprotic (acetonitrile. To evaluate the pH absorbance data, a resolution method based on the combination of soft- and hard-modeling was applied. The acidity constants of all related equilibria were estimated using the whole spectral fitting of the collected data to an established factor analysis model. The data analysis program Datan was applied for determination of the acidity constants. The corresponding pKa values were determined in water and mixed water–organic solvents. Linear relationship between the acidity constants and the mole fraction of the different sol-vents in the mixtures exist. The effect of solvent properties on acid–base behavior is discussed.

  19. Characterization of CeO2-ZrO2 mixed oxides prepared by two different co-precipitation methods

    Institute of Scientific and Technical Information of China (English)

    YUE Mei; CUI Meisheng; ZHANG Na; LONG Zhiqi; HUANG Xiaowei

    2013-01-01

    A series of cerium zirconium mixed oxides were prepared by two co-precipitation methods using magnesium hydrogen carbonate (MHC) and mixed ammonia-ammonia hydrogen carbonate (AAHC) as precipitant respectively.The crystal structure,BET surface area and morphology of the produced cerium zirconium mixed oxides were characterized by X-ray diffraction (XRD),Brumauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) techniques.The reduction-oxidation behavior and oxygen storage capacity (OSC) performance were also studied by temperature programmed reduction (TPR) and oxygen pulse chemical adsorption methods.The XRD results demonstrated that the cerium zirconium mixed oxides obtained by both methods possessed structure of cubic solid solution phase.The fresh surface area calcinated at 600 ℃,aged surface area after 1000 ℃ and OSC at 500 ℃ of cerium zirconium mixed oxides were determined to be 89.337,34.784 m2/g,and 567 μmol O2/g for MHC method and 122.010,46.307 m2/g,and 665 μmol O2/g for AAHC method,respectively.

  20. Tuning Oleophobicity of Silicon Oxide Surfaces with Mixed Monolayers of Aliphatic and Fluorinated Alcohols.

    Science.gov (United States)

    Lee, Austin W H; Gates, Byron D

    2016-12-13

    We demonstrate the formation of mixed monolayers derived from a microwave-assisted reaction of alcohols with silicon oxide surfaces in order to tune their surface oleophobicity. This simple, rapid method provides an opportunity to precisely tune the constituents of the monolayers. As a demonstration, we sought fluorinated alcohols and aliphatic alcohols as reagents to form monolayers from two distinct constituents for tuning the surface oleophobicity. The first aspect of this study sought to identify a fluorinated alcohol that formed monolayers with a relatively high surface coverage. It was determined that 1H,1H,2H,2H-perfluoro-1-octanol yielded high quality monolayers with a water contact angle (WCA) value of ∼110° and contact angle values of ∼80° with toluene and hexadecane exhibiting both an excellent hydrophobicity and oleophobicity. Tuning of the oleophobicity of the modified silicon oxide surfaces was achieved by controlling the molar ratio of 1H,1H,2H,2H-perfluoro-1-octanol within the reaction mixtures. Surface oleophobicity progressively decreased with a decrease in the fluorinated alcohol content while the monolayers maintained their hydrophobicity with WCA values of ∼110°. The simple and reliable approach to preparing monolayers of a tuned composition that is described in this article can be utilized to control the fluorocarbon content of the hydrophobic monolayers on silicon oxide surfaces.

  1. Crystal structure of a mixed-valence μ-oxide Sn12 cluster

    Directory of Open Access Journals (Sweden)

    Marina M. Kireenko

    2014-11-01

    Full Text Available The mixed-valence μ-oxide Sn12 cluster, decacarbonyltetra-μ4-oxido-hexa-μ3-oxido-tetrakis[μ-2,2′-(pyridine-2,6-diylbis(1,1-diphenylethanolato]decatin(IIditin(IVdimolybdenum(O(2 Mo—Sn toluene heptasolvate, [Mo2Sn12(C33H27NO24O10(CO10]·7C7H8, has a crystallographically imposed inversion centre. The asymmetric unit also contains three and a half toluene solvent molecules, one of which is disordered about a centre of symmetry. The complex molecule comprises six distinct Sn atom species with four different coordination numbers, namely 3, 4, 5, and 6. The SnII atoms forming the central Sn10O10 core adopt distorted trigonal–pyramidal, square-pyramidal and octahedral coordination geometries provided by the μ-oxide atoms and by the O- and N-donor atoms of two pyridinediethanolate ligands. The terminal SnIV atoms have distorted trigonal–bipyramidal coordination geometries, with a μ4-oxide atom and the N atom of a pyridinediethanolate ligand occupying the axial positions, and the Mo atom of a Mo(CO5 group and the alkoxy O atoms of a ligand forming the equatorial plane. In the crystal, weak intra- and intermolecular C—H...O hydrogen bonds are observed.

  2. Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

    Science.gov (United States)

    Tegafaw, Tirusew; Xu, Wenlong; Wasi Ahmad, Md; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

    2015-09-01

    A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd3+ (8S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy3+ (6H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd3+ and Dy3+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (davg = 1.0 nm) showed large r1 and r2 values (r2/r1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R1 and R2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T1 and T2 MR images.

  3. Crystal Structures of the Reduced, Sulfenic Acid, and Mixed Disulfide Forms of SarZ, a Redox Active Global Regulator in Staphylococcus aureus

    Energy Technology Data Exchange (ETDEWEB)

    Poor, Catherine B.; Chen, Peng R.; Duguid, Erica; Rice, Phoebe A.; He, Chuan; (UC)

    2010-01-20

    SarZ is a global transcriptional regulator that uses a single cysteine residue, Cys{sup 13}, to sense peroxide stress and control metabolic switching and virulence in Staphylococcus aureus. SarZ belongs to the single-cysteine class of OhrR-MgrA proteins that play key roles in oxidative resistance and virulence regulation in various bacteria. We present the crystal structures of the reduced form, sulfenic acid form, and mixed disulfide form of SarZ. Both the sulfenic acid and mixed disulfide forms are structurally characterized for the first time for this class of proteins. The Cys{sup 13} sulfenic acid modification is stabilized through two hydrogen bonds with surrounding residues, and the overall DNA-binding conformation is retained. A further reaction of the Cys{sup 13} sulfenic acid with an external thiol leads to formation of a mixed disulfide bond, which results in an allosteric change in the DNA-binding domains, disrupting DNA binding. Thus, the crystal structures of SarZ in three different states provide molecular level pictures delineating the mechanism by which this class of redox active regulators undergoes activation. These structures help to understand redox-mediated virulence regulation in S. aureus and activation of the MarR family proteins in general.

  4. 3D Printing Biocompatible Polyurethane/Poly(lactic acid)/Graphene Oxide Nanocomposites: Anisotropic Properties.

    Science.gov (United States)

    Chen, Qiyi; Mangadlao, Joey Dacula; Wallat, Jaqueline; De Leon, Al; Pokorski, Jonathan K; Advincula, Rigoberto C

    2017-02-01

    Blending thermoplastic polyurethane (TPU) with poly(lactic acid) (PLA) is a proven method to achieve a much more mechanically robust material, whereas the addition of graphene oxide (GO) is increasingly applied in polymer nanocomposites to tailor further their properties. On the other hand, additive manufacturing has high flexibility of structure design which can significantly expand the application of materials in many fields. This study demonstrates the fused deposition modeling (FDM) 3D printing of TPU/PLA/GO nanocomposites and its potential application as biocompatible materials. Nanocomposites are prepared by solvent-based mixing process and extruded into filaments for FDM printing. The addition of GO largely enhanced the mechanical property and thermal stability of the nanocomposites. Interestingly, we found that the mechanical response is highly dependent on printing orientation. Furthermore, the 3D printed nanocomposites exhibit good biocompatibility with NIH3T3 cells, indicating promise as biomaterials scaffold for tissue engineering applications.

  5. Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers

    Science.gov (United States)

    Liang, Qiaoli; Sherwood, Jennifer; Macher, Thomas; Wilson, Joseph M.; Bao, Yuping; Cassady, Carolyn J.

    2016-12-01

    A new matrix-assisted laser desorption ionization (MALDI) mass spectrometry matrix is proposed for molecular mass determination of polymers. This matrix contains an iron oxide nanoparticle (NP) core with citric acid (CA) molecules covalently bound to the surface. With the assistance of additives, the particulate nature of NPs allows the matrix to mix uniformly with polar or nonpolar polymer layers and promotes ionization, which may simplify matrix selection and sample preparation procedures. Several distinctively different polymer classes (polyethyleneglycol (PEG), polywax/polyethylene, perfluoropolyether, and polydimethylsiloxane) are effectively detected by the water or methanol dispersed NPCA matrix with NaCl, NaOH, LiOH, or AgNO3 as additives. Furtheremore, successful quantitative measurements of PEG1000 using polypropylene glycol 1000 as an internal standard are demonstrated.

  6. The rationale for preventing cancer cachexia: targeting excessive fatty acid oxidation

    OpenAIRE

    2016-01-01

    Cachexia commonly occurs at the terminal stage of cancer and has largely unclear molecular mechanisms. A recent study published in Nature Medicine, entitled “Excessive fatty acid oxidation induces muscle atrophy in cancer cachexia,” reveals that cachectic cancer cells can secrete multiple cytokines that induce excessive fatty acid oxidation, which is responsible for muscle loss in cancer cachexia. Inhibition of fatty acid oxidation using etomoxir can increase muscle mass and body weight in ca...

  7. Kinetics and mechanism of the oxidation of formic and oxalic acids by benzyltrimethylammonium dichloroiodate

    Indian Academy of Sciences (India)

    Poonam Gupta; Seema Kothari

    2001-04-01

    The oxidation of formic and oxalic acids by benzyltrimethylammonium dichloroiodate (BTMACI), in the presence of zinc chloride, leads to the formation of carbon dioxide. The reaction is first order with respect to BTMACI, zinc chloride and organic acid. Oxidation of deuteriated formic acid indicates the presence of a kinetic isotope effect. Addition of benzyltrimethylammonium chloride enhances the rate. It is proposed that the reactive oxidizing species is [(PhCH2Me3N)+ (IZn2Cl6)−]. Suitablemechanisms have been proposed.

  8. THE INFLUENCE OF NIOBIUM ON THE ACIDITY AND STRUCTURE OF GAMMA-ALUMINA-SUPPORTED VANADIUM OXIDES

    Directory of Open Access Journals (Sweden)

    M.N.B. Sathler

    1998-06-01

    Full Text Available Gamma-alumina-supported niobium oxide was used as a support for vanadium oxides. The influence of the addition of niobium oxide was studied by looking for changes in the structure and acid-base character of superficial species. Vanadium oxide was deposited using the continuous adsorption method; niobium oxide was impregnated using the incipient wetness method. The catalysts were characterized by XPS, UV-visible and IR spectroscopy. Catalytic tests were performed using propane oxidation reaction at 400oC. For coverage below the monolayer, both vanadium and niobium oxides were observed in slightly condensed superficial species. The presence of vanadium oxide on the support was found to increase the Lewis acidity and create some Bronsted acidity. Higher catalytic activity and selectivity for propene were associated with vanadium oxides. The presence of niobium did not contribute to the modification of the chemical properties of superficial vanadium but did decrease the adsorption of vanadium on the alumina.

  9. Synthesis of Coral-Like Tantalum Oxide Films via Anodization in Mixed Organic-Inorganic Electrolytes

    Science.gov (United States)

    Yu, Hongbin; Zhu, Suiyi; Yang, Xia; Wang, Xinhong; Sun, Hongwei; Huo, Mingxin

    2013-01-01

    We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two–electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%. PMID:23799106

  10. Synthesis of coral-like tantalum oxide films via anodization in mixed organic-inorganic electrolytes.

    Directory of Open Access Journals (Sweden)

    Hongbin Yu

    Full Text Available We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two-electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%.

  11. Effect of different mixing ways in palladium/ceria-zirconia/alumina preparation on partial oxidation of methane

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qingwei; WEN Jing; SHEN Meiqing; WANG Jun

    2008-01-01

    The effect of the mixing ways of Ce0.7Zr0.3O2-Al2O3 mixed oxides on the partial oxidations of methane (POM) was investigated over Pd/Ce0.7Zr0.3O2-Al2O3 catalysts, the mixing ways including salt precursor mixing (ATOM), precipitator mixing (MOL), and powder mechanically mixing (MECH), respectively. The test results indicated that among the three samples, Pd/ATOM had the best catalytic activity,while Pd/MOL had the best stability in the stability test. Both the activity sequences of the fresh and used samples were consistent with the order of Pd dispersion. According to the X-ray diffraction (XRD) and BET characterization, the interaction of Ce4+, Zr4+, and Al3+ in the ATOM mixed oxide was in favor of performing higher catalytic activity and thermal stability. The stability test indicated that Pd/MOL had the highest Pd dispersion and least coke formation on the active sites calculated by the H2-chemisorption and TG results, which was consid-ered to relate to its superior activity of POM to other catalysts.

  12. Second-harmonic generation in mixed stilbazium salt/arachidic acid Langmuir-Blodgett films

    Science.gov (United States)

    Liu, Liying; Zheng, Jiabiao; Wang, Wencheng; Zhang, Zhiming; Tao, Fenggang; Xu, Linxiao; Hu, Jiacong

    1992-10-01

    A stilbazium salt was synthesized and its second-order molecular polarizability was deduced to be 1.2×10 -27 esu. Measurements of second-harmonic generation and small-angle X-ray diffraction on Langmuir-Blodgett films of the stilbazium salt/arachide acid mixtures showed that the mixed compounds with molar ratios of 1:2 and 1:5 could form multilayers with large second- order optical nonlinearity. Second harmonic generation study on the alternate multilayers of stilbazium salt/arachide acid and arachidic acid showed that the second-harmonic signals were increasing monotonously up to 80 bilayers, but the increment was lower than the value predicted theoretically by the quadratic law. Possible reasons are discussed.

  13. Electrolytic reduction of mixed (Fe, Ti) oxide using molten calcium chloride electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, Mrutyunjay, E-mail: mp@mail.tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aobaku, Sendai 980-8577 (Japan); Iizuka, Atsushi; Shibata, Etsuro; Nakamura, Takashi [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aobaku, Sendai 980-8577 (Japan)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer Tan et al. have electrolyzed mixtures of TiO{sub 2} and Fe{sub 2}O{sub 3} to produce alloys containing Fe-Ti intermetallic phases such as FeTi and Fe{sub 2}Ti using the FFC process. However, the produced alloys have a porous structure with many carbon impurities, e.g., titanium carbide (TiC). Most of the carbon contamination could be caused by the presence of carbon particles in the porous alloy structure. They did not mention any obvious ways of excluding carbon and other impurities, and only suggested that the use of mixed oxides with refined structures or using a single phase, namely ilmenite (FeO{center_dot}TiO{sub 2}), were methods of decreasing impurities in the formed alloys. For future industrialization, there is an urgent need for obvious ways of producing purer Fe-Ti alloys with dense structures, rather than porous structures, as these absorb carbon impurities. Black-Right-Pointing-Pointer Finally, we successfully reduced to a highly purified Fe-Ti intermetallic alloy of FeTi and {beta}-Ti (FeTi{sub 4}) phases. FeTi phases of size around 5-10 {mu}m were dispersed in a matrix of the {beta}-Ti (FeTi{sub 4}) phase. The carbon content of the electrolyzed alloy was as low as less than 0.01 mass%. It was suggested that the dense structure of the alloy of FeTi and {beta}-Ti (FeTi{sub 4}) avoided the inclusion of carbon particle impurities, unlike the porous alloy structure. - Abstract: The production of high-purity metals or alloys using effective technologies is critical for future industrialization. With this aim in mind, a fundamental study of electrolysis in molten CaCl{sub 2} electrolytes was conducted to develop a new production process for ferrotitanium (Fe-Ti) intermetallic alloys. Mixed solid oxides of TiO{sub 2} and Fe{sub 2}O{sub 3} were used in a molar ratio of 5.44:1.00. In this composition of Ti and Fe, FeTi and {beta}-Ti containing iron can co-exist in equilibrium. A mixed solid (Fe, Ti) oxide was reduced

  14. Kinetics of oxidation of acidic amino acids by sodium N-bromobenzenesulphonamide in acid medium: A mechanistic approach

    Indian Academy of Sciences (India)

    Puttaswamy; Nirmala Vaz

    2001-08-01

    Kinetics of oxidation of acidic amino acids (glutamic acid (Glu) and aspartic acid (Asp)) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) has been carried out in aqueous HClO4 medium at 30°C. The rate shows firstorder dependence each on [BAB]o and [amino acid]o and inverse first-order on [H+]. At [H+] > 0 60 mol dm-3, the rate levelled off indicating zero-order dependence on [H+] and, under these conditions, the rate has fractional order dependence on [amino acid]. Succinic and malonic acids have been identified as the products. Variation of ionic strength and addition of the reaction product benzenesulphonamide or halide ions had no significant effect on the reaction rate. There is positive effect of dielectric constant of the solvent. Proton inventory studies in H2O-D2O mixtures showed the involvement of a single exchangeable proton of the OH- ion in the transition state. Kinetic investigations have revealed that the order of reactivity is Asp > Glu. The rate laws proposed and derived in agreement with experimental results are discussed.

  15. IDH1 mutations alter citric acid cycle metabolism and increase dependence on oxidative mitochondrial metabolism

    National Research Council Canada - National Science Library

    Grassian, Alexandra R; Parker, Seth J; Davidson, Shawn M; Divakaruni, Ajit S; Green, Courtney R; Zhang, Xiamei; Slocum, Kelly L; Pu, Minying; Lin, Fallon; Vickers, Chad; Joud-Caldwell, Carol; Chung, Franklin; Yin, Hong; Handly, Erika D; Straub, Christopher; Growney, Joseph D; Vander Heiden, Matthew G; Murphy, Anne N; Pagliarini, Raymond; Metallo, Christian M

    2014-01-01

    .... We observed that under hypoxic conditions, IDH1-mutant cells exhibited increased oxidative tricarboxylic acid metabolism along with decreased reductive glutamine metabolism, but not IDH2-mutant cells...

  16. Inhibition of oxidative metabolism by propionic acid and its reversal by carnitine in isolated rat hepatocytes.

    Science.gov (United States)

    Brass, E P; Fennessey, P V; Miller, L V

    1986-01-01

    The present study was designed to study the interaction of propionic acid and carnitine on oxidative metabolism by isolated rat hepatocytes. Propionic acid (10 mM) inhibited hepatocyte oxidation of [1-14C]-pyruvate (10 mM) by 60%. This inhibition was not the result of substrate competition, as butyric acid had minimal effects on pyruvate oxidation. Carnitine had a small inhibitory effect on pyruvate oxidation in the hepatocyte system (210 +/- 19 and 184 +/- 18 nmol of pyruvate/60 min per mg of protein in the absence and presence of 10 mM-carnitine respectively; means +/- S.E.M., n = 10). However, in the presence of propionic acid (10 mM), carnitine (10 mM) increased the rate of pyruvate oxidation by 19%. Under conditions where carnitine partially reversed the inhibitory effect of propionic acid on pyruvate oxidation, formation of propionylcarnitine was documented by using fast-atom-bombardment mass spectroscopy. Propionic acid also inhibited oxidation of [1-14C]palmitic acid (0.8 mM) by hepatocytes isolated from fed rats. The degree of inhibition caused by propionic acid was decreased in the presence of 10 mM-carnitine (41% inhibition in the absence of carnitine, 22% inhibition in the presence of carnitine). Propionic acid did not inhibit [1-14C]palmitic acid oxidation by hepatocytes isolated from 48 h-starved rats. These results demonstrate that propionic acid interferes with oxidative metabolism in intact hepatocytes. Carnitine partially reverses the inhibition of pyruvate and palmitic acid oxidation by propionic acid, and this reversal is associated with increased propionylcarnitine formation. The present study provides a metabolic basis for the efficacy of carnitine in patients with abnormal organic acid accumulation, and the observation that such patients appear to have increased carnitine requirements ('carnitine insufficiency'). PMID:3790065

  17. Oxidation states of molybdenum in oxide films formed in sulphuric acid and sodium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Okonkwo, I.A.; Doff, J.; Baron-Wiechec, A. [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom); Jones, G. [Waters Corporation, Floats Rd, Roundthorn Ind. Est., Manchester M23 9LZ (United Kingdom); Koroleva, E.V. [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom); Skeldon, P., E-mail: p.skeldon@manchester.ac.uk [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom); Thompson, G.E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2012-07-31

    X-ray photoelectron spectroscopy is used to investigate the oxidation states of molybdenum in thin films formed potentiostatically, over a range of potentials, in either 1 mol dm{sup -3} H{sub 2}SO{sub 4} or 10 mol dm{sup -3} NaOH at 20 Degree-Sign C. Mo 3d spectra suggested that MoO{sub 2} and Mo(OH){sub 2} were the main components of the films, with smaller amounts of MoO{sub 3} and possibly Mo{sub 2}O{sub 5}. O 1s spectra indicated the presence of oxygen as oxide and hydroxide species and as bound water. Ion beam analysis revealed the formation of thin films at all potentials, with significant losses of oxidized molybdenum to the electrolyte. - Highlights: Black-Right-Pointing-Pointer Oxides are formed on molybdenum in sulphuric acid and sodium hydroxide solutions. Black-Right-Pointing-Pointer Molybdenum IV and VI are identified by XPS, with MoO2 species dominating. Black-Right-Pointing-Pointer Thicknesses of films are determined by ion beam analysis for a range of potentials. Black-Right-Pointing-Pointer Films form at low efficiency due to loss of molybdenum species to electrolyte.

  18. Development and evaluation of acid-buffering bioadhesive vaginal tablet for mixed vaginal infections.

    Science.gov (United States)

    Alam, Mohd Aftab; Ahmad, Farhan Jalees; Khan, Zeenat Iqbal; Khar, Roop Krishen; Ali, Mushir

    2007-12-14

    An acid-buffering bioadhesive vaginal tablet was developed for the treatment of genitourinary tract infections. From the bioadhesion experiment and release studies it was found that polycarbophil and sodium carboxymethylcellulose is a good combination for an acid-buffering bioadhesive vaginal tablet. Sodium monocitrate was used as a buffering agent to provide acidic pH (4.4), which is an attribute of a healthy vagina. The effervescent mixture (citric acid and sodium bicarbonate) along with a superdisintegrant (Ac-Di-sol) was used to enhance the swellability of the bioadhesive tablet. The drugs clotrimazole (antifungal) and metronidazole (antiprotozoal as well as an antibacterial) were used in the formulation along with Lactobacillus acidophilus spores to treat mixed vaginal infections. From the ex vivo retention study it was found that the bioadhesive polymers hold the tablet for more than 24 hours inside the vaginal tube. The hardness of the acid-buffering bioadhesive vaginal tablet was optimized, at 4 to 5 kg hardness the swelling was found to be good and the cumulative release profile of the developed tablet was matched with a marketed conventional tablet (Infa-V). The in vitro spreadability of the swelled tablet was comparable to the marketed gel. In the in vitro antimicrobial study it was found that the acid-buffering bioadhesive tablet produces better antimicrobial action than marketed intravaginal drug delivery systems (Infa-V, Candid-V and Canesten 1).

  19. Structural and spectroscopic properties of high temperature prepared ZrO₂–TiO₂ mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Gionco, Chiara [Dipartimento di Chimica and NIS (Nanostructured Surfaces and Interfaces), Università degli Studi di Torino, Via Giuria 7, 10125 Torino (Italy); Battiato, Alfio; Vittone, Ettore [Dipartimento di Fisica, Università degli Studi di Torino, Via Giuria 1, 10125 Torino (Italy); Paganini, Maria Cristina, E-mail: mariacristina.paganini@unito.it [Dipartimento di Chimica and NIS (Nanostructured Surfaces and Interfaces), Università degli Studi di Torino, Via Giuria 7, 10125 Torino (Italy); Giamello, Elio [Dipartimento di Chimica and NIS (Nanostructured Surfaces and Interfaces), Università degli Studi di Torino, Via Giuria 7, 10125 Torino (Italy)

    2013-05-01

    ZrO₂-TiO₂ mixed oxides of various composition, with the molar fraction of TiO₂ ranging from 0.1% to 15%, have been prepared via sol-gel synthesis and then calcined at 1273 K to check both their thermal stability and physicochemical properties. These solids are usually employed in photocatalytic processes and as active phase supports in heterogeneous catalysis. As indicated by X-ray diffraction and Raman spectroscopy, solid solutions based on Ti ions diluted in the ZrO₂ matrix are formed in the whole range of Ti molar fraction examined. Materials with low Ti loading (0.1%–1%) are basically constituted by the monoclinic phase of ZrO₂ while the tetragonal phase becomes prevalent at 15% of TiO₂ molar fraction. The presence of Ti ions modify the electronic structure of the solid as revealed by investigation of the optical properties. The typical band gap transition of ZrO₂ undergoes, in fact, a red shift roughly proportional to the Ti loading which reach the remarkable value of 1.6 eV for the sample with 10% of molar Ti concentration. Comparing chemical analysis of the solids with XPS data it has been put into evidence that the titanium ions distribution into the solid is not uniform and the concentration of Ti⁴⁺ tend to be higher in subsurface layers than in the crystal bulk. The introduction of titanium ions in the structure increases the reducibility of the solid. Annealing under vacuum at various temperatures causes oxygen depletion with consequent reduction of the solid which shows up mainly in terms of formation of Ti³⁺ reduced centres which are characterized by a typical EPR signal. Ti³⁺ defects forms, as also forecast by theoretical modelling of the solid, as their energy is lower than that of other possible reduced defective centers. The reduced solids are able to transfer electrons to adsorbed oxygen molecules in mild condition resulting in the formation of surface superoxide anions (O₂⁻) which are stabilized on surface Zr

  20. Nanosecond multi-pulse laser-induced damage mechanisms in pure and mixed oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Frank R., E-mail: frank.wagner@fresnel.fr; Gouldieff, Céline, E-mail: celine.gouldieff@univ-rennes1.fr; Natoli, Jean-Yves, E-mail: jean-yves.natoli@fresnel.fr; Commandré, Mireille, E-mail: mireille.commandre@fresnel.fr

    2015-10-01

    We report on nanosecond laser-induced damage of pure and mixed oxide thin films deposited by ion beam sputtering. Silica, hafnia and alumina as well as their binary mixtures have been tested in S-on-1 mode at 355 nm and 266 nm using a multiscale approach. The results were analyzed qualitatively to discuss the different fatigue behaviors observed. The absence of a multi-photon absorption step in the 1-on-1 damage thresholds as a function of the band gap indicates defect-mediated damage mechanisms. During the multi-pulse experiments we observed laser-induced defects that cause fatigue effects and preexisting low-density defects, which are insensitive to multiple pulse irradiation. Depending on material and beam size both types of defects (preexisting and light-induced) may contribute equally to the observed damage probability. Comparing the fatigue behavior of the mixtures to their constituting pure oxides, we found that, in general, the fatigue behavior of binary mixtures cannot be interpolated from the behaviors of the pure oxides. - Highlights: • Multi-pulse laser damage can be analyzed plotting damaging shot number vs. fluence. • A fatigue effect was only observed for small laser beams, avoiding worse precursors. • The fatigue behavior of a mixture cannot be interpolated from the pure oxides. • SiO{sub 2} and Al{sub 2}O{sub 3} damage at 266 nm is due to deterministic material modifications. • Hafnia multi-pulse laser damage with small beams is stochastic even at 266 nm.

  1. Extractive oxidative desulfurization of model oil/crude oil using KSF montmorillonite-supported 12-tungstophosphoric acid

    Directory of Open Access Journals (Sweden)

    Ezzat Rafiee

    2016-10-01

    Full Text Available Abstract 12-Tungstophosphoric acid (PW supported on KSF montmorillonite, PW/KSF, was used as catalyst for deep oxidative desulfurization (ODS of mixed thiophenic compounds in model oil and crude oil under mild conditions using hydrogen peroxide (H2O2 as an oxidizing agent. A one-factor-at-a-time method was applied for optimizing the parameters such as temperature, reaction time, amount of catalyst, type of extractant and oxidant-to-sulfur compounds (S-compounds molar ratio. The corresponding products can be easily removed from the model oil by using ethanol as the best extractant. The results showed high catalytic activity of PW/KSF in the oxidative removal of dibenzothiophene (DBT and mixed thiophenic model oil under atmospheric pressure at 75 °C in a biphasic system. To investigate the oxidation and adsorption effects of crude oil composition on ODS, the effects of cyclohexene, 1,7-octadiene and o-xylene with different concentrations were studied.

  2. Triiodothyronine activates lactate oxidation without impairing fatty acid oxidation and improves weaning from extracorporeal membrane oxygenation

    Energy Technology Data Exchange (ETDEWEB)

    Kajimoto, Masaki; Ledee, Dolena R.; Xu, Chun; Kajimoto, Hidemi; Isern, Nancy G.; Portman, Michael A.

    2014-01-01

    Background: Extracorporeal membrane oxygenation (ECMO) provides a rescue for children with severe cardiac failure. We previously showed that triiodothyronine (T3) improves cardiac function by modulating pyruvate oxidation during weaning. This study was focused on fatty acid (FA) metabolism modulated by T3 for weaning from ECMO after cardiac injury. Methods: Nineteen immature piglets (9.1-15.3 kg) were separated into 3 groups with ECMO (6.5 hours) and wean: normal circulation (Group-C);transient coronary occlusion (10 minutes) followed by ECMO (Group-IR); and IR with T3 supplementation (Group-IR-T3). 13-Carbon labeled lactate, medium-chain and long-chain FAs were infused as oxidative substrates. Substrate fractional contribution to the citric acid cycle (FC) was analyzed by 13-Carbon nuclear magnetic resonance. Results: ECMO depressed circulating T3 levels to 40% baseline at 4 hours and were restored in Group-IR-T3. Group-IR decreased cardiac power, which was not fully restorable and 2 pigs were lost because of weaning failure. Group-IR also depressed FC-lactate, while the excellent contractile function and energy efficiency in Group-IR-T3 occurred along with a marked FC-lactate increase and [ATP]/[ADP] without either decreasing FC-FAs or elevating myocardial oxygen consumption over Group-C or -IR. Conclusions: T3 releases inhibition of lactate oxidation following ischemia-reperfusion injury without impairing FA oxidation. These findings indicate that T3 depression during ECMO is maladaptive, and that restoring levels improves metabolic flux and enhances contractile function during weaning.

  3. Influence of thermal treatments on the basic and catalytic properties of Mg,Al-mixed oxides derived from hydrotalcites

    Directory of Open Access Journals (Sweden)

    R. Bastiani

    2004-06-01

    Full Text Available This work studied the influence of calcination conditions on basic properties and catalytic performance of Mg,Al-mixed oxides derived from a hydrotalcite sample (Al/(Al+Mg=0.20. Various heating rates, calcination atmospheres and lengths of calcination at 723K were evaluated. TPD of CO2 and retroaldolization of diacetone alcohol (DAA were used to determine the basic properties of the mixed oxides. The basic site density determined by TPD of CO2 showed a better correlation with catalytic activity for acetone/citral aldol condensation than the relative basicity obtained from retroaldolization of DAA. Calcination atmosphere was the parameter that influenced most the basic and the catalytic properties of the Mg,Al-mixed oxides, with calcination under dry air being the best choice.

  4. Mixed micelle formation between amino acid-based surfactants and phospholipids.

    Science.gov (United States)

    Faustino, Célia M C; Calado, António R T; Garcia-Rio, Luís

    2011-07-15

    The mixed micelle formation in aqueous solutions between an anionic gemini surfactant derived from the amino acid cystine (C(8)Cys)(2), and the phospholipids 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC, a micelle-forming phospholipid) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC, a vesicle-forming phospholipid) has been studied by conductivity and the results compared with the ones obtained for the mixed systems with the single-chain surfactant derived from cysteine, C(8)Cys. Phospholipid-surfactant interactions were found to be synergistic in nature and dependent on the type of phospholipid and on surfactant hydrophobicity. Regular solution theory was used to analyse the gemini surfactant-DHPC binary mixtures and the interaction parameter, β(12), has been evaluated, as well as mixed micelle composition. The results have been interpreted in terms of the interplay between reduction of the electrostatic repulsions among the ionic head groups of the surfactants and steric hindrances arising from incorporation of the zwitterionic phospholipids in the mixed micelles.

  5. Evaluation of mono or mixed cultures of lactic acid bacteria in type II sourdough system.

    Science.gov (United States)

    Ekinci, Raci; Şimşek, Ömer; Küçükçuban, Ayca; Nas, Sebahattin

    2016-01-01

    The aim of this study was to evaluate the use of mono and mixed lactic acid bacteria (LAB) cultures to determine suitable LAB combinations for a type II sourdough system. In this context, previously isolated sourdough LAB strains with antimicrobial activity, which included Lactobacillus plantarum PFC22, Lactobacillus brevis PFC31, Pediococcus acidilactici PFC38, and Lactobacillus sanfranciscensis PFC80, were used as mono or mixed culture combinations in a fermentation system to produce type II sourdough, and subsequently in bread dough production. Compared to the monoculture fermentation of dough, the use of mixed cultures shortened the adaptation period by half. In addition, the use of mixed cultures ensured higher microbial viability, and enhanced the fruity flavor during bread dough production. It was determined that the combination of L. plantarum PFC22 + P. acidilactici PFC38 + L. sanfranciscensis PFC80 is a promising culture mixture that can be used in the production of type II sourdough systems, and that may also contribute to an increase in metabolic activity during bread production process.

  6. Graphene Oxide-Gallic Acid Nanodelivery System for Cancer Therapy

    Science.gov (United States)

    Dorniani, Dena; Saifullah, Bullo; Barahuie, Farahnaz; Arulselvan, Palanisamy; Hussein, Mohd Zobir Bin; Fakurazi, Sharida; Twyman, Lance J.

    2016-11-01

    Despite the technological advancement in the biomedical science, cancer remains a life-threatening disease. In this study, we designed an anticancer nanodelivery system using graphene oxide (GO) as nanocarrier for an active anticancer agent gallic acid (GA). The successful formation nanocomposite (GOGA) was characterized using XRD, FTIR, HRTEM, Raman, and UV/Vis spectroscopy. The release study shows that the release of GA from the designed anticancer nanocomposite (GOGA) occurs in a sustained manner in phosphate-buffered saline (PBS) solution at pH 7.4. In in vitro biological studies, normal fibroblast (3T3) and liver cancer cells (HepG2) were treated with different concentrations of GO, GOGA, and GA for 72 h. The GOGA nanocomposite showed the inhibitory effect to cancer cell growth without affecting normal cell growth. The results of this research are highly encouraging to go further for in vivo studies.

  7. Kinetic study of formic acid oxidation on carbon supported Pd electrocatalyst

    Science.gov (United States)

    Wang, Yujiao; Wu, Bing; Gao, Ying; Tang, Yawen; Lu, Tianhong; Xing, Wei; Liu, Changpeng

    The oxidation of formic acid at the Pd/C catalyst electrode is a completely irreversible kinetic process with the reaction order of 1.0. The oxidation rate of formic acid is increased with increasing the concentration of formic acid and is decreased with increasing H + concentration. The apparent negative reaction order with respect to H + is about -0.18 or -0.04 in H 2SO 4 or HClO 4 solution respectively, because bisulfate anions would inhibit formic acid oxidation at some extent. The kinetic parameters, charge transfer coefficient and the diffusion coefficient of formic acid were obtained under the quasi steady-state conditions.

  8. Structure, activity and kinetics of supported molybdenum oxide and mixed molybdenum-vanadium oxide catalysts prepared by flame spray pyrolysis for propane OHD

    DEFF Research Database (Denmark)

    Høj, Martin; Kessler, Thomas; Beato, Pablo

    2013-01-01

    reflectance UV-vis spectroscopy and evaluated as catalysts for the oxidative dehydrogenation (ODH) of propane. The results show that samples with high specific surface areas between 122 and 182 m2/g were obtained, resulting in apparent MoOx and VOx surface densities from 0.7 to 7.7 nm -2 and 1.5 to 1.9 nm-2......, respectively. Raman spectroscopy, UV-vis spectroscopy and XRD confirmed the high dispersion of molybdenum and vanadia species on γ-Al2O3 as the main crystalline phase. Only at the highest loading of 15 wt% Mo, with theoretically more than monolayer coverage, some crystalline molybdenum oxide was observed....... For the mixed molybdenum-vanadium oxide catalysts the surface species were separate molybdenum oxide and vanadium oxide monomers at low loadings of molybdenum, but with increasing molybdenum loading interactions between surface molybdenum and vanadium oxide species were observed with Raman spectroscopy...

  9. Fluorine and chlorine determination in mixed uranium-plutonium oxide fuel and plutonium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Elinson, S.V.; Zemlyanukhina, N.A.; Pavlova, I.V.; Filatkina, V.P.; Tsvetkova, V.T.

    1981-01-01

    A technique of fluorine and chlorine determination in the mixed uranium-plutonium oxide fuel and plutonium dioxide, based on their simultaneous separation by means of pyrohydrolysis, is developed. Subsequently, fluorine is determined by photometry with alizarincomplexonate of lanthanum or according to the weakening of zirconium colouring with zylenol orange. Chlorine is determined using the photonephelometric method according to the reaction of chloride-ion interaction with silver nitrate or by spectrophotometric method according to the reaction with mercury rhodanide. The lower limit of fluorine determination is -6x10/sup -5/ %, of chlorine- 1x10/sup -4/% in the sample of 1g. The relative mean quadratic deviation of the determination result (Ssub(r)), depends on the character of the material analyzed and at the content of nx10/sup -4/ - nx10/sup -3/ mass % is equal to from 0.05 to 0.32 for fluorine and from 0.11 to 0.35 for chlorine.

  10. Effect of CO2 on the Conversion of Isobutane over Iron, Cerium and Molybdenum Mixed Oxides

    Directory of Open Access Journals (Sweden)

    Daifallah Al-Dhayan

    2016-10-01

    Full Text Available A series of cerium and iron mixed oxide catalysts were prepared by thermal decomposition of Fe1.5PMo12O40 and Ce1.5PMo12O40 heteropolyanions mixture. The prepared catalysts have been characterized and tested for the conversion of isobutane in the presence of CO2. Characterization by XRD showed that besides Fe2O3 and CeO2, α-MoO3 was the main phase formed after thermal treatment. The effect of the support, the reaction temperature, and the presence of H2O in the reactant mixture was investigated. It has been found that the support enhanced both the conversion and isobutene selectivity. As for the reaction temperature and addition of water, it has been found that increasing the temperature increased both the conversion and isobutene selectivity, whereas the presence of water increased the isobutene selectivity but decreased the conversion.

  11. The underwater coincidence counter (UWCC) for plutonium measurements in mixed oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Eccleston, G.W.; Menlove, H.O.; Abhold, M.; Baker, M.; Pecos, J.

    1998-12-31

    The use of fresh uranium-plutonium mixed oxide (MOX) fuel in light-water reactors (LWR) is increasing in Europe and Japan and it is necessary to verify the plutonium content in the fuel for international safeguards purposes. The UWCC is a new instrument that has been designed to operate underwater and nondestructively measure the plutonium in unirradiated MOX fuel assemblies. The UWCC can be quickly configured to measure either boiling-water reactor (BWR) or pressurized-water reactor (PWR) fuel assemblies. The plutonium loading per unit length is measured using the UWCC to precisions of less than 1% in a measurement time of 2 to 3 minutes. Initial calibrations of the UWCC were completed on measurements of MOX fuel in Mol, Belgium. The MCNP-REN Monte Carlo simulation code is being benchmarked to the calibration measurements to allow accurate simulations for extended calibrations of the UWCC.

  12. Mixed transition-metal oxides: design, synthesis, and energy-related applications.

    Science.gov (United States)

    Yuan, Changzhou; Wu, Hao Bin; Xie, Yi; Lou, Xiong Wen David

    2014-02-03

    A promising family of mixed transition-metal oxides (MTMOs) (designated as Ax B3-x O4 ; A, B=Co, Ni, Zn, Mn, Fe, etc.) with stoichiometric or even non-stoichiometric compositions, typically in a spinel structure, has recently attracted increasing research interest worldwide. Benefiting from their remarkable electrochemical properties, these MTMOs will play significant roles for low-cost and environmentally friendly energy storage/conversion technologies. In this Review, we summarize recent research advances in the rational design and efficient synthesis of MTMOs with controlled shapes, sizes, compositions, and micro-/nanostructures, along with their applications as electrode materials for lithium-ion batteries and electrochemical capacitors, and efficient electrocatalysts for the oxygen reduction reaction in metal-air batteries and fuel cells. Some future trends and prospects to further develop advanced MTMOs for next-generation electrochemical energy storage/conversion systems are also presented.

  13. The underwater coincidence counter for plutonium measurements in mixed-oxide fuel assemblies manual

    Energy Technology Data Exchange (ETDEWEB)

    G. W. Eccleston; H. O. Menlove; M. Abhold; M. Baker; J. Pecos

    1999-05-01

    This manual describes the Underwater Coincidence Counter (UWCC) that has been designed for the measurement of plutonium in mixed-oxide (MOX) fuel assemblies prior to irradiation. The UWCC uses high-efficiency {sup 3}He neutron detectors to measure the spontaneous-fission and induced-fission rates in the fuel assembly. Measurements can be made on MOX fuel assemblies in air or underwater. The neutron counting rate is analyzed for singles, doubles, and triples time correlations to determine the {sup 240}Pu effective mass per unit length of the fuel assembly. The system can verify the plutonium loading per unit length to a precision of less than 1% in a measurement time of 2 to 3 minutes. System design, components, performance tests, and operational characteristics are described in this manual.

  14. Thermochemical prediction of chemical form distributions of fission products in LWR mixed oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Moriyama, Kouki; Furuya, Hirotaka [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1998-06-01

    Radial distribution of chemical forms of fission products (FPs) in LWR mixed oxide (MOX) fuel pins was theoretically predicted by a thermochemical computer code SOLGASMIX-PV. The amounts of fission products generated in the fuel were calculated by ORIGEN-2 code, and the radial distributions of temperature and oxygen potential were calculated by taking the neutron depression and oxygen redistribution in the fuel into account. A fuel pellet was radially divided into 51 sections and chemical forms of FPs were calculated in each section. The effects of linear heat rating (LHR) and average O/U ratio on radial distribution of chemical form were evaluated. It was found that the radial distribution of chemical forms depends strongly on the LHR and the O/M ratio, and is not proportional to that of burnup. (author)

  15. Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

    Directory of Open Access Journals (Sweden)

    Hirokazu Nakayama

    2014-07-01

    Full Text Available The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

  16. Supercritical water oxidation of acrylic acid production wastewater.

    Science.gov (United States)

    Gong, Y M; Wang, S Z; Tang, X Y; Xu, D H; Ma, H H

    2014-01-01

    Supercritical water oxidation (SCWO) of wastewater from an acrylic acid manufacturing plant has been studied on a continuous flow experimental system, whose reactor was made of Hastelloy C-276. Experimental conditions included a reaction temperature (T) ranging from 673 to 773K, a residence time (t) ranging from 72.7 to 339s, a constant pressure (P) of 25 MPa and a fixed oxidation coefficient (alpha) of 2.0. Experimental results indicated that reaction temperature and residence time had significant influences on the oxidation reaction, and increasing the two operation parameters could improve both degradation of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). The COD removal efficiency could reach up to 98.73% at 25 MPa, 773 K and 180.1 s, whereas the destruction efficiency of NH3-N was only 43.71%. We further carried out a kinetic analysis considering the induction period through free radical chain mechanism. It confirms that the power-law rate equation for COD removal was 345 exp(-52200/RT)[COD]1.98[O2]0.17 and for NH3-N removal was 500 exp(-64492.19/RT)[NH3-N]1.87 [O2]0.03. Moreover, the induction time formulations for COD and NH3-N were suspected to be exp(38250/RT)/173 and exp(55690/RT)/15231, respectively. Correspondingly, induction time changed from 2.22 to 5.38 s for COD and 0.38 to 1.38 s for NH3-N. Owing to the catalysis of reactor inner wall surface, more than 97% COD removal was achieved in all samples.

  17. Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

    Science.gov (United States)

    Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

    2016-10-20

    In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Mixed Nanostructured Ti-W Oxides Films for Efficient Electrochromic Windows

    Directory of Open Access Journals (Sweden)

    Nguyen Nang Dinh

    2012-01-01

    Full Text Available With the aim to enhance the electrochromic (EC efficiency and electrochemical stability of electrochromic devices (ECD, mixed nanostructured TiO2/WO3 films were prepared by an electrochemical deposition method with the purpose of adding WO3 nanoparticles to porous nanocrystalline doctor-blade TiO2 (nc-TiO2 films. The results of the characterization of electrochromic properties in 1 M LiClO4 + propylene carbonate (LiClO4 + PC of both the nc-TiO2/F-doped tin oxide (FTO and WO3/TiO2/FTO configurations showed the reversible coloration and bleaching of the ECDs. The response time of the ECD coloration of WO3/TiO2/FTO was found to be as small as 2 sec, and its coloration efficiency (CE as high as 35.7 cm2 × C−1. By inserting WO3 nanoparticles into the porous TiO2 structures, WO3/TiO2 heterojunctions were formed in the films, consequently enabling both the CE and electrochemical stability of the working electrodes to be considerably enhanced. Since a large-area WO3/TiO2 can be prepared by the doctor-blade technique followed by the electrochemical deposition process, mixed nanostructured Ti-W oxides electrodes constitute a good candidate for smart window applications, taking advantage of the excellent coloration and stability properties as well as the simple and economical fabrication process involved.

  19. Thorium-based mixed oxide fuel in a pressurized water reactor: A feasibility analysis with MCNP

    Science.gov (United States)

    Tucker, Lucas Powelson

    This dissertation investigates techniques for spent fuel monitoring, and assesses the feasibility of using a thorium-based mixed oxide fuel in a conventional pressurized water reactor for plutonium disposition. Both non-paralyzing and paralyzing dead-time calculations were performed for the Portable Spectroscopic Fast Neutron Probe (N-Probe), which can be used for spent fuel interrogation. Also, a Canberra 3He neutron detector's dead-time was estimated using a combination of subcritical assembly measurements and MCNP simulations. Next, a multitude of fission products were identified as candidates for burnup and spent fuel analysis of irradiated mixed oxide fuel. The best isotopes for these applications were identified by investigating half-life, photon energy, fission yield, branching ratios, production modes, thermal neutron absorption cross section and fuel matrix diffusivity. 132I and 97Nb were identified as good candidates for MOX fuel on-line burnup analysis. In the second, and most important, part of this work, the feasibility of utilizing ThMOX fuel in a pressurized water reactor (PWR) was first examined under steady-state, beginning of life conditions. Using a three-dimensional MCNP model of a Westinghouse-type 17x17 PWR, several fuel compositions and configurations of a one-third ThMOX core were compared to a 100% UO2 core. A blanket-type arrangement of 5.5 wt% PuO2 was determined to be the best candidate for further analysis. Next, the safety of the ThMOX configuration was evaluated through three cycles of burnup at several using the following metrics: axial and radial nuclear hot channel factors, moderator and fuel temperature coefficients, delayed neutron fraction, and shutdown margin. Additionally, the performance of the ThMOX configuration was assessed by tracking cycle length, plutonium destroyed, and fission product poison concentration.

  20. Palladium-catalyzed air-based oxidative coupling of arylboronic acids with H-phosphine oxides leading to aryl phosphine oxides.

    Science.gov (United States)

    Fu, Tingting; Qiao, Hongwei; Peng, Zhimin; Hu, Gaobo; Wu, Xueji; Gao, Yuxing; Zhao, Yufen

    2014-05-14

    We present a novel and highly efficient methodology that allows for the construction of C-P bonds via the palladium-catalyzed air-based oxidative coupling of various commercially available arylboronic acids with easily oxidized H-phosphine oxides leading to valuable aryl phosphine oxides, particularly triarylphosphine oxides, with the use of air as the green oxidant, broad substrate applicability and good to excellent yields. The described catalytic system should be an efficient complement to the Chan-Lam type reaction and be useful in synthetic programs.

  1. Removal of Hazardous Pollutants from Wastewaters: Applications of TiO2-SiO2 Mixed Oxide Materials

    Directory of Open Access Journals (Sweden)

    Shivatharsiny Rasalingam

    2014-01-01

    Full Text Available The direct release of untreated wastewaters from various industries and households results in the release of toxic pollutants to the aquatic environment. Advanced oxidation processes (AOP have gained wide attention owing to the prospect of complete mineralization of nonbiodegradable organic substances to environmentally innocuous products by chemical oxidation. In particular, heterogeneous photocatalysis has been demonstrated to have tremendous promise in water purification and treatment of several pollutant materials that include naturally occurring toxins, pesticides, and other deleterious contaminants. In this work, we have reviewed the different removal techniques that have been employed for water purification. In particular, the application of TiO2-SiO2 binary mixed oxide materials for wastewater treatment is explained herein, and it is evident from the literature survey that these mixed oxide materials have enhanced abilities to remove a wide variety of pollutants.

  2. The incorporation of graphene oxide into polysulfone mixed matrix membrane for CO2/CH4 separation

    Science.gov (United States)

    Zahri, K.; Goh, P. S.; Ismail, A. F.

    2016-06-01

    Carbon dioxide (CO2) is often found as the main impurity in natural gas, where methane (CH4) is the major component. The presence of CO2 in natural gas leads to several problems such as reducing the energy content of natural gas and cause pipeline corrosion. Thus it must be removed to meet specifications (CO2 ≤ 2 mol%) before the gas can be delivered to the pipeline. In this work, hollow fiber mixed matrix membrane (MMM) were fabricated by embedding graphene oxide (GO) into a polysulfone (PSf) polymer matrix to improve membrane properties as well as its separation performance towards CO2/CH4 gas. The membrane properties were investigated for pristine membrane and mixed matrix membrane filled with filler loading of 0.25%. The synthesized GO and properties of fabricated membranes were characterized and studied using TEM, AFM, XRD, FTIR and SEM respectively. The permeance of pure gases and ideal selectivity of CO2/CH4 gas were determined using pure gas permeation experiment. GO has affinity towards CO2 gas. The nanosheet structure creates path for small molecule gas and restricted large molecule gas to pass through the membrane. The incorporation of GO in PSf polymer enhanced the permeance of CO 2 and CO2/CH4 separation from 64.47 to 86.80 GPU and from 19 to 25 respectively.

  3. Tunable Mixed Ionic/Electronic Conductivity and Permittivity of Graphene Oxide Paper for Electrochemical Energy Conversion.

    Science.gov (United States)

    Bayer, Thomas; Bishop, Sean R; Perry, Nicola H; Sasaki, Kazunari; Lyth, Stephen M

    2016-05-11

    Graphene oxide (GO) is a two-dimensional graphitic carbon material functionalized with oxygen-containing surface functional groups. The material is of interest in energy conversion, sensing, chemical processing, gas barrier, and electronics applications. Multilayer GO paper has recently been applied as a new proton conducting membrane in low temperature fuel cells. However, a detailed understanding of the electrical/dielectric properties, including separation of the ionic vs electronic contributions under relevant operating conditions, has so far been lacking. Here, the electrical conductivity and dielectric permittivity of GO paper are investigated in situ from 30 to 120 °C, and from 0 to 100% relative humidity (RH) using impedance spectroscopy. These are related to the water content, measured by thermogravimetric analysis. With the aid of electron blocking measurements, GO is demonstrated to be a mixed electronic-protonic conductor, and the ion transference number is derived for the first time. For RH > 40%, conductivity is dominated by proton transport (with a maximum of 0.5 mS/cm at 90 °C and 100% RH). For RH proton conducting electrolyte but also as a mixed conducting electrode material under appropriate conditions. Such materials are highly applicable in electrochemical energy conversion and storage devices such as fuel cells and electrolyzers.

  4. Consolidated bioprocessing for butyric acid production from rice straw with undefined mixed culture

    Directory of Open Access Journals (Sweden)

    Binling Ai

    2016-10-01

    Full Text Available Lignocellulosic biomass is a renewable source with great potential for biofuels and bioproducts. However, the cost of cellulolytic enzymes limits the utilization of the low-cost bioresource. This study aimed to develop a consolidated bioprocessing without the need of supplementary cellulase for butyric acid production from lignocellulosic biomass. A stirred-tank reactor with a working volume of 21 L was constructed and operated in batch and semi-continuous fermentation modes with a cellulolytic butyrate-producing microbial community. The semi-continuous fermentation with intermittent discharging of the culture broth and replenishment with fresh medium achieved the highest butyric acid productivity of 2.69 g/(L•d. In semi-continuous operation mode, the butyric acid and total carboxylic acid concentrations of 16.2 and 28.9 g/L, respectively, were achieved. Over the 21-day fermentation period, their cumulative yields reached 1189 and 2048 g, respectively, corresponding to 41% and 74% of the maximum theoretical yields based on the amount of NaOH pretreated rice straw fed in. This study demonstrated that an undefined mixed culture-based consolidated bioprocessing for butyric acid production can completely eliminate the cost of supplementary cellulolytic enzymes.

  5. Violent explosion after inadvertent mixing of nitric acid and isopropanol – Review 15 years later finds basic accident data corrupted, no evidence of broad learning

    DEFF Research Database (Denmark)

    Hedlund, Frank Huess; Folmer Nielsen, Merete; Hagen Mikkelsen, Sonja

    2014-01-01

    steel tank disintegrated with such force that fragments lodged in walls of concrete. The explosion ravaged the cellar, destroyed equipment, blew out a masonry wall and released large amounts of nitrous oxide fumes. Likely, 62% nitric acid (CAS 7697-37-2) and isopropanol (2-propanol, CAS 67-63-0) reacted...... the brewery to court for negligence, they did not report or investigate the accident, or attempt to disseminate information available to them. Today, the general literature is silent on the explosion hazards of mixing the two chemicals. The paper argues that without institutional support, learning...

  6. Comparison of the redox activities of sol-gel and conventionally prepared Bi-Mo-Ti mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Wildberger, M.; Grundwaldt, J.D.; Mallat, T.; Baiker, A. [Lab. of Technical Chemistry, Swiss Federal Inst. of Technology, ETH-Zentrum, Zuerich (Switzerland)

    1998-12-31

    Novel sol-gel Bi-Mo-Ti oxides have been prepared and characterized by XRD, XPS, FT-Raman and HRTEM. The surface Bi{sup 3+} and Mo{sup 6+} species of some xerogels and an aerogel could be reduced and oxidized at room temperature, whereas the conventionally prepared reference materials were not reduced by H{sub 2} below 300 C. The unusual redox properties, under very mild conditions, are likely due to the unique morphology of Bi-Mo-oxides stabilized by titania. During butadiene oxidation to furan at above 400 C to sol-gel mixed oxides restructured considerably and their performance was barely better than that of titania-supported Bi-Mo oxides. (orig.)

  7. Fatty Acid Incubation of Myotubues from Humans with Type 2 Diabetes Leads to Enhanced Release of Beta Oxidation Products Due to Impaired Fatty Acid Oxidation

    DEFF Research Database (Denmark)

    Wensaas, Andreas J; Rustan, Arild C; Just, Marlene

    2008-01-01

    Objective: Increased availability of fatty acids is important for accumulation of intracellular lipids and development of insulin resistance in human myotubes. It is unknown whether different types of fatty acids like eicosapentaenoic acid (EPA) or tetradecylthioacetic acid (TTA) influence...... these processes. Research Design and Methods: We examined fatty acid and glucose metabolism, and gene expression in cultured human skeletal muscle cells from control and T2D individuals after four days preincubation with EPA or TTA. Results: T2D myotubes exhibited reduced formation of CO(2) from palmitic acid (PA....... EPA markedly enhanced TAG accumulation in myotubes, more pronounced in T2D cells. TAG accumulation and fatty acid oxidation were inversely correlated only after EPA preincubation, and total level of acyl-CoA was reduced. Glucose oxidation (CO(2) formation) was enhanced and lactate production decreased...

  8. Nitric Acid Dehydration Using Perfluoro Carboxylate and Mixed Sulfonate/Carboxylate Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Richard L. [Colorado School of Mines, Golden, CO (United States)

    2004-09-01

    Perfluoro ionomer membranes are tetrafluoro ethylene-based materials with microheterogeneous structures consisting of a hydrophobic polymer backbone and a hydrophilic side-chain cluster region. Due to the ionomer cluster morphology, these films exhibit unique transport properties. Recent investigations with perfluoro sulfonate and perfluoro sulfonate/carboxylate composite polymers have demonstrated their value in the dehydration of nitric acid and they show potential as an alternative to conventional, energy intensive unit operations in the concentration of acid feeds. As a result, investigations were conducted to determine the feasibility of using pure perfluoro carboxylate and mixed perfluoro sulfonate/carboxylate films for the dehydration of nitric acid because of the speculation of improved water selectivity of the carboxylate pendant chain. During the first phase of these investigations the effort was focused on generating a thin, solution cast perfluoro carboxylate ionomer film, to evaluate the general, chemical and physical characteristics of the polymer, and to assess the material's aqueous transport performance (flux and nitrate separation efficiencies) in pervaporation and high-pressure environments. Results demonstrated that generating robust solution-cast films was difficult yet a number of membranes survived high trans-membrane pressures up to 700 psig. General characterization of the solution cast product showed reduced ion exchange capacities when compared with thicker, ''as received'' perfluoro carboxylate and similar sulfonate films. Small angle x-ray scattering analysis results suggested that the solution cast carboxylate films contained a small fraction of sulfonate terminated side-chains. Aqueous transport experimentation showed that permeate fluxes for both pure water and nitric acid were approximately two orders of magnitude smaller for the carboxylate solution cast membranes when compared to their sulfonate

  9. Persistence of Metal-rich Particles Downstream Zones of Acid Drainage Mixing in Andean Rivers

    Science.gov (United States)

    Pasten, P.; Montecinos, M.; Guerra, P. A.; Bonilla, C. A.; Escauriaza, C. R.; Dabrin, A.; Coquery, M.

    2016-12-01

    The Andes mountain range provides the setting for watersheds with high natural background of metals and for mining operations that enhance contaminant mobilization, notably in Northern and Central Chile. Dissolved and solid metal species are actively transported by streams to the Pacific Ocean from area and point sources, like acid drainage. We examine the response of metal rich particle suspensions downstream zones of mixing where shifts in the chemical environment occur. We propose a conceptual model which is used to analyze the fate of copper in the upper Mapocho watershed. The main source of copper is the Yerba Loca river, a naturally impacted stream with pH ranging from 3 to 7 and high concentrations of Cu (0.8 - 6.3 mg/L), Al (1.3 - 7.6 mg/L) and Fe (0.4 - 4.2 mg/L). Steep chemical shifts occur after the confluences with the San Francisco and the Molina rivers. We characterized stream chemistry, hydrological variables and suspended particles, including particle size distribution (PSD), turbidity, and total suspended solids. A marked seasonal behavior was observed, with a higher total Cu flux during smelting periods and a shift towards the dissolved phase during summer. When acid drainage is discharged into a receiving stream, incomplete mixing occurs thereby promoting the formation of a range of metal-rich solids with a characteristic PSD. Similarly, areas of chemical heterogeneity control the partition of metals associated to suspended geomaterials coming from bank and slope erosion. A highly dynamic process ensues where metastable phases shift to new equilibria as fully mixed conditions are reached. Depending on the reaction kinetics, some particles persist despite being exposed to thermodynamically unfavorable chemical environments. The persistence of metal-rich particles downstream zones of acid drainage mixing is important because it ultimately controls the flux of metals being delivered to the ocean by watersheds impacted by acid drainage. Funding from

  10. EBSD and TEM characterization of high burn-up mixed oxide fuel

    Science.gov (United States)

    Teague, Melissa; Gorman, Brian; Miller, Brandon; King, Jeffrey

    2014-01-01

    Understanding and studying the irradiation behavior of high burn-up oxide fuel is critical to licensing of future fast breeder reactors. Advancements in experimental techniques and equipment are allowing for new insights into previously irradiated samples. In this work dual column focused ion beam (FIB)/scanning electron microscope (SEM) was utilized to prepared transmission electron microscope samples from mixed oxide fuel with a burn-up of 6.7% FIMA. Utilizing the FIB/SEM for preparation resulted in samples with a dose rate of <0.5 mRem/h compared to ∼1.1 R/h for a traditionally prepared TEM sample. The TEM analysis showed that the sample taken from the cooler rim region of the fuel pellet had ∼2.5× higher dislocation density than that of the sample taken from the mid-radius due to the lower irradiation temperature of the rim. The dual column FIB/SEM was additionally used to prepared and serially slice ∼25 μm cubes. High quality electron back scatter diffraction (EBSD) were collected from the face at each step, showing, for the first time, the ability to obtain EBSD data from high activity irradiated fuel.

  11. Enrichment and characteristics of mixed methane-oxidizing bacteria from a Chinese coal mine.

    Science.gov (United States)

    Jiang, Hao; Duan, Changhong; Luo, Mingfang; Xing, Xin-Hui

    2016-12-01

    In methane-rich environments, methane-oxidizing bacteria usually occur predominantly among consortia including other types of microorganisms. In this study, artificial coal bed gas and methane gas were used to enrich mixed methanotrophic cultures from the soil of a coal mine in China, respectively. The changes in microbial community structure and function during the enrichment were examined. The microbial diversity was reduced as the enrichment proceeded, while the capacity for methane oxidation was significantly enhanced by the increased abundance of methanotrophs. The proportion of type II methanotrophs increased greatly from 7.84 % in the sampled soil to about 50 % in the enrichment cultures, due to the increase of methane concentration. After the microbial community of the cultures got stable, Methylomonas and Methylocystis became the dominant type I and type II methanotrophs, while Methylophilus was the prevailing methylotroph. The sequences affiliated with pigment-producing strains, Methylomonas rubra, Hydrogenophaga sp. AH-24, and Flavobacterium cucumis, could explain the orange appearance of the cultures. Comparing the two cultures, the multi-carbon sources in the artificial coal bed gas caused more variety of non-methanotrophic bacteria, but did not help to maintain the diversity or to increase the quantity and activity of methanotrophs. The results could help to understand the succession and interaction of microbial community in a methane-driven ecosystem.

  12. Vapor phase hydrogenation of furfural over nickel mixed metal oxide catalysts derived from layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Sulmonetti, Taylor P.; Pang, Simon H.; Claure, Micaela Taborga; Lee, Sungsik; Cullen, David A.; Agrawal, Pradeep K.; Jones, Christopher W.

    2016-05-01

    The hydrogenation of furfural is investigated over various reduced nickel mixed metal oxides derived from layered double hydroxides (LDHs) containing Ni-Mg-Al and Ni-Co-Al. Upon reduction, relatively large Ni(0) domains develop in the Ni-Mg-Al catalysts, whereas in the Ni-Co-Al catalysts smaller metal particles of Ni(0) and Co(0), potentially as alloys, are formed, as evidenced by XAS, XPS, STEM and EELS. All the reduced Ni catalysts display similar selectivities towards major hydrogenation products (furfuryl alcohol and tetrahydrofurfuryl alcohol), though the side products varied with the catalyst composition. The 1.1Ni-0.8Co-Al catalyst showed the greatest activity per titrated site when compared to the other catalysts, with promising activity compared to related catalysts in the literature. The use of base metal catalysts for hydrogenation of furanic compounds may be a promising alternative to the well-studied precious metal catalysts for making biomass-derived chemicals if catalyst selectivity can be improved in future work by alloying or tuning metal-oxide support interactions.

  13. Water gas shift reaction over Cu catalyst supported by mixed oxide materials for fuel cell application

    Directory of Open Access Journals (Sweden)

    Tepamatr Pannipa

    2016-01-01

    Full Text Available The water gas shift activities of Cu on ceria and Gd doped ceria have been studied for the further enhancement of hydrogen purity [1] after the steam reforming of ethanol. The catalytic properties of commercial catalysts were also studied to compare with the as-prepared catalysts. Copper-containing cerium oxide materials are shown in this work to be suitable for the high temperature. Copper-ceria is a stable high-temperature shift catalyst, unlike iron-chrome catalysts that deactivate severely in CO2-rich gases. We found that 5%Cu/10%GDC(D has much higher activity than other copper ceria based catalysts. The finely dispersed CuO species is favorable to the higher activity, which explained the activity enhancement of this catalyst. The kinetics of the WGS reaction over Cu catalysts supported by mixed oxide materials were measured in the temperature range 200-400 °C. An independence of the CO conversion rate on CO2 and H2 was found.

  14. A solid oxide photoelectrochemical cell with UV light-driven oxygen storage in mixed conducting electrodes

    Science.gov (United States)

    Walch, Gregor; Rotter, Bernhard; Brunauer, Georg Christoph; Esmaeili, Esmaeil; Opitz, Alexander Karl; Kubicek, Markus; Summhammer, Johann; Ponweiser, Karl

    2017-01-01

    A single crystalline SrTiO3 working electrode in a zirconia-based solid oxide electrochemical cell is illuminated by UV light at temperatures of 360–460 °C. In addition to photovoltaic effects, this leads to the build-up of a battery-type voltage up to more than 300 mV. After switching off UV light, this voltage only slowly decays. It is caused by UV-induced oxygen incorporation into the mixed conducting working electrode and thus by changes of the oxygen stoichiometry δ in SrTiO3–δ under UV illumination. These changes of the oxygen content could be followed in time-dependent voltage measurements and also manifest themselves in time-dependent resistance changes during and after UV illumination. Discharge currents measured after UV illumination reveal that a large fraction of the existing oxygen vacancies in SrTiO3 become filled under UV light. Additional measurements on cells with TiO2 thin film electrodes show the broader applicability of this novel approach for transforming light into chemical energy and thus the feasibility of solid oxide photoelectrochemical cells (SOPECs) in general and of a “light-charged oxygen battery” in particular. PMID:28261480

  15. Graphene Oxide Reinforced Polylactic Acid/Polyurethane Antibacterial Composites

    Directory of Open Access Journals (Sweden)

    Xiaoli An

    2013-01-01

    Full Text Available Nanocomposites from PLA/PU containing small concentrations of graphene oxide (GO were prepared by simple liquid-phase mixing followed by casting. The as-prepared ternary PLA/PU/GO composite films exhibited good antibacterial activity against the gram-positive Staphylococcus aureus and the gram-negative Escherichia coli, due to the excellent antibacterial property of GO sheets with high specific surface area. The addition of GO inhibited the attachment and proliferation of microbes on the film surfaces, resulting in that the PLA/PU/GO composite films show remarkably improved antibacterial activity compared with PLA/PU composite film. The inhibition efficiency is proportional to the amount of GO. Furthermore, PLA/PU/GO composite fibrous paper was fabricated using electrospinning and exhibited good biocompatibility. The addition of GO does not destroy normal cell’s proliferation and differentiation. PLA/PU/GO composites with good antibacterial activity and biocompatibility make it attractive for the environmental and clinical applications and also provide a candidate for future application of tissue engineering.

  16. Integrating nitric oxide into salicylic acid and jasmonic acid/ethylene plant defense pathways

    DEFF Research Database (Denmark)

    Mur, Luis A J; Prats, Elena; Pierre, Sandra

    2013-01-01

    Plant defence against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defence responses...... to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signalling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signalling along...... the cytoplasm to reduce TGA activation. In JA biosynthesis, NO will initiate the expression of JA biosynthetic enzymes, presumably to over-come any antagonistic effects of SA on JA-mediated transcription. NO will also initiate the expression of ET biosynthetic genes but a suppressive role is also observed...

  17. Application of Ni-Oxide@TiO2 Core-Shell Structures to Photocatalytic Mixed Dye Degradation, CO Oxidation, and Supercapacitors

    Directory of Open Access Journals (Sweden)

    Seungwon Lee

    2016-12-01

    Full Text Available Performing diverse application tests on synthesized metal oxides is critical for identifying suitable application areas based on the material performances. In the present study, Ni-oxide@TiO2 core-shell materials were synthesized and applied to photocatalytic mixed dye (methyl orange + rhodamine + methylene blue degradation under ultraviolet (UV and visible lights, CO oxidation, and supercapacitors. Their physicochemical properties were examined by field-emission scanning electron microscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, and UV-visible absorption spectroscopy. It was shown that their performances were highly dependent on the morphology, thermal treatment procedure, and TiO2 overlayer coating.

  18. Effect of loading content of copper oxides on performance of Mn-Cu mixed oxide catalysts for catalytic combustion of benzene

    Institute of Scientific and Technical Information of China (English)

    CAO Hongyan; LI Xiaoshuang; CHEN Yaoqiang; GONG Maochu; WANG Jianli

    2012-01-01

    A series of Mn-Cu mixed oxide catalysts were prepared by precipitation method.The catalysts were characterized by N2 adsorption-desorption,H2-TPR and XPS.When the loading ratio of manganese oxides to copper oxides was 8:2 or 7:3,the catalysts possessed better catalytic activity,and benzene was converted completely at 558 K.Results of H2-TPR showed that the loading of a small amount of copper oxides decreased the reduction temperature of catalysts.Results of XPS showed that the loading of a small amount of copper oxides increased the proportion of manganese and defective oxygen on the surface of catalysts,and stabilized manganese at higher oxidation state.And the catalyst with the loading ratio 7:3 was a little worse than 8:2,since the interaction between manganese oxides and copper oxides is too strong,copper oxides migrate to the surface of catalysts and manganese oxides in excess are immerged.

  19. Aerobic bacterial pyrite oxidation and acid rock drainage during the Great Oxidation Event.

    Science.gov (United States)

    Konhauser, Kurt O; Lalonde, Stefan V; Planavsky, Noah J; Pecoits, Ernesto; Lyons, Timothy W; Mojzsis, Stephen J; Rouxel, Olivier J; Barley, Mark E; Rosìere, Carlos; Fralick, Phillip W; Kump, Lee R; Bekker, Andrey

    2011-10-19

    The enrichment of redox-sensitive trace metals in ancient marine sedimentary rocks has been used to determine the timing of the oxidation of the Earth's land surface. Chromium (Cr) is among the emerging proxies for tracking the effects of atmospheric oxygenation on continental weathering; this is because its supply to the oceans is dominated by terrestrial processes that can be recorded in the Cr isotope composition of Precambrian iron formations. However, the factors controlling past and present seawater Cr isotope composition are poorly understood. Here we provide an independent and complementary record of marine Cr supply, in the form of Cr concentrations and authigenic enrichment in iron-rich sedimentary rocks. Our data suggest that Cr was largely immobile on land until around 2.48 Gyr ago, but within the 160 Myr that followed--and synchronous with independent evidence for oxygenation associated with the Great Oxidation Event (see, for example, refs 4-6)--marked excursions in Cr content and Cr/Ti ratios indicate that Cr was solubilized at a scale unrivalled in history. As Cr isotope fractionations at that time were muted, Cr must have been mobilized predominantly in reduced, Cr(III), form. We demonstrate that only the oxidation of an abundant and previously stable crustal pyrite reservoir by aerobic-respiring, chemolithoautotrophic bacteria could have generated the degree of acidity required to solubilize Cr(III) from ultramafic source rocks and residual soils. This profound shift in weathering regimes beginning at 2.48 Gyr ago constitutes the earliest known geochemical evidence for acidophilic aerobes and the resulting acid rock drainage, and accounts for independent evidence of an increased supply of dissolved sulphate and sulphide-hosted trace elements to the oceans around that time. Our model adds to amassing evidence that the Archaean-Palaeoproterozoic boundary was marked by a substantial shift in terrestrial geochemistry and biology.

  20. Preparation and Physical Properties of Chitosan Benzoic Acid Derivatives Using a Phosphoryl Mixed Anhydride System

    Directory of Open Access Journals (Sweden)

    Kyu Yun Chai

    2012-02-01

    Full Text Available Direct benzoylation of the two hydroxyl groups on chitosan was achieved using a phosphoryl mixed anhydride system, derived from trifluoroacetic anhydride (TFAA, benzoic acids (BAs, and phosphoric acid (PA. The reaction is operated as a one pot process under mild conditions that does not require neither an inert atmosphere nor dry solvents. The structures of the synthesized compounds were confirmed by NMR and IR spectroscopy. Solubility tests on the products revealed that they were soluble in organic solvents such as N,N-dimethylformamide (DMF, dimethylsulfoxide (DMSO, and acetone. In the meantime, a morphological study by scanning electron microscopy (SEM evidently indicated that the chitosan benzoates underwent significant structural changes after the benzoylation.

  1. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Science.gov (United States)

    2010-07-01

    ... ester with pentaerythritol. 721.3680 Section 721.3680 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  2. Study of Oxidation of Glutathione Treated with Hypochlorous Acid by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Capillary electrophoresis (CE) method was developed for the separation and quantification of reduced glutathione (GSH), oxidized glutathione (GSSG) and glutathione sulphonic acid (GSO3H). Baseline separation was obtained within five minutes. The effects of reaction time and molar ratio of hypochlorous acid (HOCI) to GSH on the oxidation of GSH were investigated.

  3. Neuropsychological Outcomes in Fatty Acid Oxidation Disorders: 85 Cases Detected by Newborn Screening

    Science.gov (United States)

    Waisbren, Susan E.; Landau, Yuval; Wilson, Jenna; Vockley, Jerry

    2013-01-01

    Mitochondrial fatty acid oxidation disorders include conditions in which the transport of activated acyl-Coenzyme A (CoA) into the mitochondria or utilization of these substrates is disrupted or blocked. This results in a deficit in the conversion of fat into energy. Most patients with fatty acid oxidation defects are now identified through…

  4. Hepatic fatty acid oxidation : activity, localization and function of some enzymes involved

    NARCIS (Netherlands)

    A. van Tol (Arie)

    1971-01-01

    textabstractFatty acid oxidation is an important pathway for energy production in mammals and birds. In animal tissues the enzymes of fatty acid oxidation are located in the mitochondrion. Recent reports suggest that this is not the case in Castor bean endosperm. In this tissue the enzymes of

  5. The effect of conjugated linoleic acid supplements on oxidative and antioxidative status of dairy cows.

    Science.gov (United States)

    Hanschke, N; Kankofer, M; Ruda, L; Höltershinken, M; Meyer, U; Frank, J; Dänicke, S; Rehage, J

    2016-10-01

    Dairy cows develop frequently negative energy balance around parturition and in early lactation, resulting in excessive mobilization of body fat and subsequently in increased risk of ketosis and other diseases. Dietary conjugated linoleic acid (CLA) supplements are used in dairy cows mainly for their depressing effect on milk fat content, but are also proposed to have antioxidative properties. As negative energy balance is associated with oxidative stress, which is also assumed to contribute to disease development, the present study was conducted to examine effects of CLA on oxidative and antioxidative status of lactating dairy cows. German Holstein cows (primiparous n=13, multiparous n=32) were divided into 3 dietary treatment groups receiving 100g/d of control fat supplement, containing 87% stearic acid (CON; n=14), 50g/d of control fat supplement and 50g/d of CLA supplement (CLA 50; n=15), or 100g/d of CLA supplement (CLA 100; n=16). The CLA supplement was lipid-encapsulated and contained 12% of trans-10,cis-12 CLA and cis-9,trans-11 CLA each. Supplementation took place between d1 and 182 postpartum; d 182 until 252 postpartum served as a depletion period. Blood was sampled at d -21, 1, 21, 70, 105, 140, 182, 224, and 252 relative to calving. The antioxidative status was determined using the ferric-reducing ability of plasma, α-tocopherol, α-tocopherol-to-cholesterol mass ratio, and retinol. For determination of oxidative status concentrations of hydroperoxides, thiobarbituric acid-reactive substances (TBARS), N'-formylkynurenine, and bityrosine were measured. Mixed models of fixed and random effects with repeated measures were used to evaluate period 1 (d -21 to 140) and 2 (d182-252) separately. Cows showed increased oxidative stress and lipid peroxidation during the periparturient period in terms of increased serum concentrations of hydroperoxides and TBARS, which decreased throughout lactation. During period 1, the supplemented cows had lower TBARS

  6. Stimulation of polyunsaturated fatty acid oxidation in myocytes by regulating its cellular uptake

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-aleem, S.; Frangakis, C. (Glaxo Inc., Research Triangle Park, NC (USA)); Badr, M. (Univ. of Missouri-Kansas City, MO (USA))

    1991-01-01

    In order to investigate the regulation of polyunsaturated fatty acid oxidation in the heart, the effect of the phosphodiesterase inhibitor enoximone on the oxidation of (1-{sup 14}C) arachidonic acid, and (1-{sup 14}C) arachidonyl-CoA, were studied in adult rat myocytes, and isolated rat heart mitochondria. Enoximone stimulated arachidonate oxidation by 94%, at a concentration of 0.25 mM. The apparent Vmax value of archidonate oxidation in the presence of enoximone was approximately 75% higher than the value observed with the control in isolated myocytes. Also, enoximone stimulated arachidonate uptake by 27% at a concentration of 0.25 mM. On the other hand, enoximone had no effect on the oxidation of (1-{sup 14}C) arachidonyl-CoA in isolated rat heart mitochondria. These results suggest that the oxidation of polyunsaturated fatty acids in myocytes is regulated by the rate of uptake of these acids across sarcolemmal membranes.

  7. Enzymology of the branched-chain amino acid oxidation disorders: the valine pathway.

    Science.gov (United States)

    Wanders, Ronald J A; Duran, Marinus; Loupatty, Ference J

    2012-01-01

    Valine is one of the three branched-chain amino acids which undergoes oxidation within mitochondria. In this paper, we describe the current state of knowledge with respect to the enzymology of the valine oxidation pathway and the different disorders affecting oxidation.

  8. Reduction reaction analysis of nanoparticle copper oxide for copper direct bonding using formic acid

    Science.gov (United States)

    Fujino, Masahisa; Akaike, Masatake; Matsuoka, Naoya; Suga, Tadatomo

    2017-04-01

    Copper direct bonding is required for electronics devices, especially power devices, and copper direct bonding using formic acid is expected to lower the bonding temperature. In this research, we analyzed the reduction reaction of copper oxide using formic acid with a Pt catalyst by electron spin resonance analysis and thermal gravimetry analysis. It was found that formic acid was decomposed and radicals were generated under 200 °C. The amount of radicals generated was increased by adding the Pt catalyst. Because of these radicals, both copper(I) oxide and copper(II) oxide start to be decomposed below 200 °C, and the reduction of copper oxide is accelerated by reactants such as H2 and CO from the decomposition of formic acid above 200 °C. The Pt catalyst also accelerates the reaction of copper oxide reduction. Herewith, it is considered that the copper surface can be controlled more precisely by using formic acid to induce direct bonding.

  9. Enhancing the crystalline degree of carbon nanotubes by acid treatment, air oxidization and heat treatment

    Institute of Scientific and Technical Information of China (English)

    Chensha Li; Baoyou Zhang; Xingjuan Chen; Xiaoqing Hu; Ji Liang

    2005-01-01

    Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect.Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.

  10. Manoyl oxide alpha-arabinopyranoside and grindelic acid diterpenoids from Grindelia integrifolia.

    Science.gov (United States)

    Ahmed, A A; Mahmoud, A A; Ahmed, U M; El-Bassuony, A A; Abd El-Razk, M H; Pare, P W; Karchesy, J

    2001-10-01

    Two new manoyl oxide-alpha-arabinopyranoside diterpenoids, 15-hydroxy-13-epi-manoyl oxide-14-O-alpha-L-arabinopyranoside (tarapacol-14-O-alpha-L-arabinopyranoside) (1) and 15-acetoxy-13-epi-manoyl oxide-14-O-alpha-L-arabinopyranoside (tarapacol-15-acetate-14-O-alpha-L-arabinopyranoside) (2), as well as a new grindelic acid derivative, 19-hydroxygrindelic acid (3), together with five known diterpenoids (tarapacol, tarapacanol A, grindelic acid, methyl grindeloate, 3beta-hydroxygrindelic acid, 4) were isolated from the aerial parts of Grindelia integrifolia. The structures of 1-3 were elucidated by spectral data analysis.

  11. Elucidating the Higher Stability of Vanadium (V) Cations in Mixed Acid Based Redox Flow Battery Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, M.; Wang, Wei; Nie, Zimin; Sprenkle, Vincent L.; Hu, Jian Z.

    2013-11-01

    The Vanadium (V) cation structures in mixed acid based electrolyte solution were analysed by density functional theory (DFT) based computational modelling and 51V and 35Cl Nuclear Magnetic Resonance (NMR) spectroscopy. The Vanadium (V) cation exists as di-nuclear [V2O3Cl2.6H2O]2+ compound at higher vanadium concentrations (≥1.75M). In particular, at high temperatures (>295K) this di-nuclear compound undergoes ligand exchange process with nearby solvent chlorine molecule and forms chlorine bonded [V2O3Cl2.6H2O]2+ compound. This chlorine bonded [V2O3Cl2.6H2O]2+ compound might be resistant to the de-protonation reaction which is the initial step in the precipitation reaction in Vanadium based electrolyte solutions. The combined theoretical and experimental approach reveals that formation of chlorine bonded [V2O3Cl2.6H2O]2+ compound might be central to the observed higher thermal stability of mixed acid based Vanadium (V) electrolyte solutions.

  12. Self-structuring foods based on acid-sensitive low and high acyl mixed gellan systems to impact on satiety

    Science.gov (United States)

    Bradbeer, Jennifer F.; Hancocks, Robin; Spyropoulos, Fotios; Norton, Ian T.

    2014-01-01

    This study investigated the in vitro acid-induced gelation of mixed systems of two biopolymers; low acyl and high acyl gellan gum. Rheological and texture analysis showed that these mixed gels displayed textures that lay between the material properties exhibited for the low and high acyl variants. DSC analysis showed that mixtures of the low acyl and high acyl forms exhibit two separate conformational transitions at temperatures coincident with each of the individual biopolymers. Various metabolically relevant pH environments and hydrocolloid concentrations were investigated. These resulted in very different acid gelled structures, which were characterised by texture analysis. The structures of the acid gels were shown to depend upon the pH, hydrocolloid concentration and proportion of each biopolymer used during their production. A selection of these mixed gellan structures were assessed post-production in terms of their response to prolonged exposure to an acidic (pH 1), stomach-like, environment. This resulted in a significant increase in the gel strength, regardless of the biopolymer proportions. The high acyl gellan was less acid-sensitive, and subsequently no evidence of acid gelation was observed with high acyl gellan at a proportion greater than 60% of the total biopolymer. The findings presented here demonstrate that structuring as well as de-structuring of mixed gellan acid gels can be controlled in acidic environments similar to those that are present in the stomach after food consumption. PMID:24882914

  13. Improved catalytic activity and stability using mixed sulfonic acid- and hydroxy-bearing polymer brushes in microreactors

    NARCIS (Netherlands)

    Ricciardi, R.; Munirathinam, Rajesh; Huskens, Jurriaan; Verboom, Willem

    2014-01-01

    Sulfonic acid-bearing polymer brushes were grown on the inner walls of continuous flow glass microreactors and used in the acid-catalyzed hydrolysis of benzaldehyde dimethyl acetal as a test reaction. Randomly 1:1 mixed polymer brushes of poly-3-sulfopropyl methacrylate (PSPM) and

  14. Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene

    Science.gov (United States)

    Bradley, P.M.; Chapelle, F.H.; Lovley, D.R.

    1998-01-01

    Anaerobic oxidation of [1,2-14C]vinyl chloride and [1,2- 14C]dichloroethene to 14CO2 under humic acid-reducing conditions was demonstrated. The results indicate that waterborne contaminants can be oxidized by using humic acid compounds as electron acceptors and suggest that natural aquatic systems have a much larger capacity for contaminant oxidation than previously thought.

  15. 77 FR 70193 - Shaw Areva MOX Services (Mixed Oxide Fuel Fabrication Facility); Notice of Atomic Safety and...

    Science.gov (United States)

    2012-11-23

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Shaw Areva MOX Services (Mixed Oxide Fuel Fabrication Facility); Notice of Atomic Safety and Licensing Board Reconstitution Pursuant to 10 CFR 2.313(c) and 2.321(b), the Atomic Safety and...

  16. Technology, safety and costs of decommissioning a reference small mixed oxide fuel fabrication plant. Volume 1. Main report

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, C. E.; Murphy, E. S.; Schneider, K J

    1979-01-01

    Detailed technology, safety and cost information are presented for the conceptual decommissioning of a reference small mixed oxide fuel fabrication plant. Alternate methods of decommissioning are described including immediate dismantlement, safe storage for a period of time followed by dismantlement and entombment. Safety analyses, both occupational and public, and cost evaluations were conducted for each mode.

  17. Measurement and modelling of the defect chemistry and transport properties of ceramic oxide mixed ionic and electronic conductors

    NARCIS (Netherlands)

    Dalslet, Bjarke Thomas

    2008-01-01

    The mixed ionic and electronic conducting fluorite and perovskite materials examined in this thesis are all oxide ion conducting materials. The defect chemistry and transport properties of a number of these materials are measured using: 1) a measurement technique using an oxygen pump and an electrol

  18. Measurement and modelling of the defect chemistry and transport properties of ceramic oxide mixed ionic and electronic conductors

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas

    2008-01-01

    The subject of this thesis is ceramic mixed ionic and electronic conductors (MIECs). MIECs have potential uses, such as solid oxygen permeation membranes, as catalysts, and as components in fuel cells. The MIECs examined in this thesis are all oxide ion conducting materials. This thesis describes...

  19. General synthesis of vanadium-based mixed metal oxides hollow nanofibers for high performance lithium-ion batteries

    Science.gov (United States)

    Xiang, Juan; Yu, Xin-Yao; Paik, Ungyu

    2016-10-01

    Hollow nanostructured mixed metal oxides have recently been intensively investigated as electrode materials for energy storage and conversion due to their remarkable electrochemical properties. Although great efforts have been made, the synthesis of hollow nanostructured vanadium-based mixed metal oxides especially those with one dimensional structure is rarely reported. Vanadium-based mixed metal oxides are promising electrode materials for lithium-ion batteries with high capacity and good rate capability. Here, we develop a facile and general method for the synthesis of one dimensional MxV2O8 (M = Co, Ni, Fe) tubular structure through a simple single-spinneret electrospinning technique followed by a calcination process. As a demonstration, Co3V2O8 hollow nanofibers are evaluated as anode materials for lithium-ion batteries. As expected, benefiting from their unique one dimensional tubular structure, the as-synthesized Co3V2O8 exhibits excellent electrochemical properties for lithium storage. To be specific, it can deliver a high specific capacity of 900 mAh g-1 at 5 A g-1, and long cycling stability up to 2000 cycles. The present work makes a significant contribution to the design and synthesis of mixed metal oxides with one dimensional tubular structure, as well as their potential applications in electrochemical energy storage.

  20. Acid-base and catalytic properties of the products of oxidative thermolysis of double complex compounds

    Science.gov (United States)

    Pechenyuk, S. I.; Semushina, Yu. P.; Kuz'mich, L. F.; Ivanov, Yu. V.

    2016-01-01

    Acid-base properties of the products of thermal decomposition of [M(A)6] x; [M1(L)6] y (where M is Co, Cr, Cu, Ni; M1 is Fe, Cr, Co; A is NH3, 1/2 en, 1/2 pn, CO(NH2)2; and L is CN, 1/2C2O4) binary complexes in air and their catalytic properties in the oxidation reaction of ethanol with atmospheric oxygen are studied. It is found that these thermolysis products are mixed oxides of the central atoms of complexes characterized by pH values of the zero charge point in the region of 4-9, OH-group sorption limits from 1 × 10-4 to 4.5 × 10-4 g-eq/g, OH-group surface concentrations of 10-50 nm-2 in 0.1 M NaCl solutions, and S sp from 3 to 95 m2/g. Their catalytic activity is estimated from the apparent rate constant of the conversion of ethanol in CO2. The values of constants are (1-6.5) × 10-5 s-1, depending on the gas flow rate and the S sp value.

  1. Analysis of microbial community variation during the mixed culture fermentation of agricultural peel wastes to produce lactic acid.

    Science.gov (United States)

    Liang, Shaobo; Gliniewicz, Karol; Gerritsen, Alida T; McDonald, Armando G

    2016-05-01

    Mixed cultures fermentation can be used to convert organic wastes into various chemicals and fuels. This study examined the fermentation performance of four batch reactors fed with different agricultural (orange, banana, and potato (mechanical and steam)) peel wastes using mixed cultures, and monitored the interval variation of reactor microbial communities with 16S rRNA genes using Illumina sequencing. All four reactors produced similar chemical profile with lactic acid (LA) as dominant compound. Acetic acid and ethanol were also observed with small fractions. The Illumina sequencing results revealed the diversity of microbial community decreased during fermentation and a community of largely lactic acid producing bacteria dominated by species of Lactobacillus developed.

  2. Effect of water vapor on the CO and CH_4 catalytic oxidation over CeO_2-MO_x (M=Cu, Mn, Fe, Co, and Ni) mixed oxide

    Institute of Scientific and Technical Information of China (English)

    乔东升; 卢冠忠; 郭耘; 王艳芹; 郭杨龙

    2010-01-01

    CeO2-MOx (M=Cu, Mn, Fe, Co, and Ni) mixed oxide catalysts were prepared by a citric acid complexation-combustion method. CeO2-MOx solid solutions could be formed with M cations doping into CeO2 lattice, while NiO and Co3O4 phases were detected on the surface of CeO2-NiO and CeO2-Co3O4 by Raman spectroscopy. The presence of M in CeO2 could obviously promote its catalytic activity for CH4 catalytic combustion and CO oxidation. Among the prepared samples, CeO2-CuO exhibited the best performance for CO oxidatio...

  3. Mixed oxide fuels testing in the advanced test reactor to support plutonium disposition

    Energy Technology Data Exchange (ETDEWEB)

    Ryskamp, J.M.; Sterbentz, J.W.; Chang, G.S. [and others

    1995-09-01

    An intense worldwide effort is now under way to find means of reducing the stockpile of weapons-grade plutonium. One of the most attractive solutions would be to use WGPu as fuel in existing light water reactors (LWRs) in the form of mixed oxide (MOX) fuel - i.e., plutonia (PUO{sub 2}) mixed with urania (UO{sub 2}). Before U.S. reactors could be used for this purpose, their operating licenses would have to be amended. Numerous technical issues must be resolved before LWR operating licenses can be amended to allow the use of MOX fuel. These issues include the following: (1) MOX fuel fabrication process verification, (2) Whether and how to use burnable poisons to depress MOX fuel initial reactivity, which is higher than that of urania, (3) The effects of WGPu isotopic composition, (4) The feasibility of loading MOX fuel with plutonia content up to 7% by weight, (5) The effects of americium and gallium in WGPu, (6) Fission gas release from MOX fuel pellets made from WGPu, (7) Fuel/cladding gap closure, (8) The effects of power cycling and off-normal events on fuel integrity, (9) Development of radial distributions of burnup and fission products, (10) Power spiking near the interfaces of MOX and urania fuel assemblies, and (11) Fuel performance code validation. We have performed calculations to show that the use of hafnium shrouds can produce spectrum adjustments that will bring the flux spectrum in ATR test loops into a good approximation to the spectrum anticipated in a commercial LWR containing MOX fuel while allowing operation of the test fuel assemblies near their optimum values of linear heat generation rate. The ATR would be a nearly ideal test bed for developing data needed to support applications to license LWRs for operation with MOX fuel made from weapons-grade plutonium. The requirements for planning and implementing a test program in the ATR have been identified.

  4. The behaviour of transuranic mixed oxide fuel in a Candu-900 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Morreale, A. C.; Ball, M. R.; Novog, D. R.; Luxat, J. C. [Dept. of Engineering Physics, McMaster Univ., 1280 Main St. W, Hamilton, ON (Canada)

    2012-07-01

    The production of transuranic actinide fuels for use in current thermal reactors provides a useful intermediary step in closing the nuclear fuel cycle. Extraction of actinides reduces the longevity, radiation and heat loads of spent material. The burning of transuranic fuels in current reactors for a limited amount of cycles reduces the infrastructure demand for fast reactors and provides an effective synergy that can result in a reduction of as much as 95% of spent fuel waste while reducing the fast reactor infrastructure needed by a factor of almost 13.5 [1]. This paper examines the features of actinide mixed oxide fuel, TRUMOX, in a CANDU{sup R}* nuclear reactor. The actinide concentrations used were based on extraction from 30 year cooled spent fuel and mixed with natural uranium in 3.1 wt% actinide MOX fuel. Full lattice cell modeling was performed using the WIMS-AECL code, super-cell calculations were analyzed in DRAGON and full core analysis was executed in the RFSP 2-group diffusion code. A time-average full core model was produced and analyzed for reactor coefficients, reactivity device worth and online fuelling impacts. The standard CANDU operational limits were maintained throughout operations. The TRUMOX fuel design achieved a burnup of 27.36 MWd/kg HE. A full TRUMOX fuelled CANDU was shown to operate within acceptable limits and provided a viable intermediary step for burning actinides. The recycling, reprocessing and reuse of spent fuels produces a much more sustainable and efficient nuclear fuel cycle. (authors)

  5. Dual Electrospray Pyrolysis for Mixed Metal Oxide (and Carbon) Composite Nanoparticle Synthesis with Applications in Energy Storage

    Science.gov (United States)

    Tang, Justin; Liu, Wen; Wang, Hailiang; Gomez, Alessandro

    We present a novel approach to synthesizing mixed metal oxide nanoparticles with a continuous, scalable aerosol flow process using the electrospray. The electrospray is a liquid atomization technique that generates a monodisperse population of highly charged liquid droplets over a broad size range (nanometric to tens of microns). Each liquid droplet serves as a micro-reactor, containing a payload of suitable precursors (such as metal nitrides), allowing for precise control over particle composition and size. By using two electrosprays of opposite polarities, the two highly charged droplets plumes are electrostatically mixed to produce a charge-neutral aerosol. Electrostatically driven droplet-droplet collisions can also be used to control morphology to some degree. This aerosol is passed through a tubular furnace via carrier gas, pyrolizing the precursors to synthesize nanomaterials. We apply this approach to manganese oxide, cobalt oxide, and carbon composite nanoparticles for use in energy storage applications.

  6. Dynamics of nitrogen oxides and ozone above and within a mixed hardwood forest in Northern Michigan

    Directory of Open Access Journals (Sweden)

    B. Seok

    2012-12-01

    Full Text Available The dynamic behavior of nitrogen oxides (NOx = NO + NO2 and ozone (O3 above and within the canopy at the University of Michigan Biological Station AmeriFlux (UMBS Flux site was investigated by continuous multi-height vertical gradient measurements during the summer and the fall of 2008. A daily maximum in nitric oxide (NO levels was consistently observed during the morning hours between 06:00 and 09:00 EST above the canopy. Daily NO maxima ranged between 0.2 and 2 ppbv (with a median of 0.3 ppbv, which was 2 to 20 times above its atmospheric background. The sources and causes of this NO maximum were evaluated using NOx and O3 measurements and synoptic and micrometeorological data. This analysis was further supported by numerical simulations with a multi-layer canopy exchange model implemented into a single-column chemistry-climate model. The observations indicated that the morning NO maximum was caused by the photolysis of NO2 from non-local air masses, which were transported into the canopy from aloft during the morning breakup of the nocturnal boundary layer. The analysis of simulated process tendencies indicated that the downward turbulent transport of NOx into the canopy compensates for the removal of NOx through chemistry and dry deposition. The sensitivity of NOx and O3 concentrations on soil and foliage NOx emissions was also assessed with the model. Uncertainties associated with the emissions of NOx from the soil or from leaf-surface nitrate photolysis did not explain the observed diurnal behavior in NOx (and O3, and in particular, the morning NOx peak mixing ratio. However, when considering the existence of a NO2 compensation point, an increase in the early morning NOx and NO peak mixing ratios by ~30% was simulated. This increase suggests the potential

  7. Mixed-phase oxide catalyst based on Mn-mullite (Sm, Gd)Mn2O5 for NO oxidation in diesel exhaust.

    Science.gov (United States)

    Wang, Weichao; McCool, Geoffrey; Kapur, Neeti; Yuan, Guang; Shan, Bin; Nguyen, Matt; Graham, Uschi M; Davis, Burtron H; Jacobs, Gary; Cho, Kyeongjae; Hao, Xianghong

    2012-08-17

    Oxidation of nitric oxide (NO) for subsequent efficient reduction in selective catalytic reduction or lean NO(x) trap devices continues to be a challenge in diesel engines because of the low efficiency and high cost of the currently used platinum (Pt)-based catalysts. We show that mixed-phase oxide materials based on Mn-mullite (Sm, Gd)Mn(2)O(5) are an efficient substitute for the current commercial Pt-based catalysts. Under laboratory-simulated diesel exhaust conditions, this mixed-phase oxide material was superior to Pt in terms of cost, thermal durability, and catalytic activity for NO oxidation. This oxide material is active at temperatures as low as 120°C with conversion maxima of ~45% higher than that achieved with Pt. Density functional theory and diffuse reflectance infrared Fourier transform spectroscopy provide insights into the NO-to-NO(2) reaction mechanism on catalytically active Mn-Mn sites via the intermediate nitrate species.

  8. Hepatic oleate regulates adipose tissue lipogenesis and fatty acid oxidation.

    Science.gov (United States)

    Burhans, Maggie S; Flowers, Matthew T; Harrington, Kristin R; Bond, Laura M; Guo, Chang-An; Anderson, Rozalyn M; Ntambi, James M

    2015-02-01

    Hepatic steatosis is associated with detrimental metabolic phenotypes including enhanced risk for diabetes. Stearoyl-CoA desaturases (SCDs) catalyze the synthesis of MUFAs. In mice, genetic ablation of SCDs reduces hepatic de novo lipogenesis (DNL) and protects against diet-induced hepatic steatosis and adiposity. To understand the mechanism by which hepatic MUFA production influences adipose tissue stores, we created two liver-specific transgenic mouse models in the SCD1 knockout that express either human SCD5 or mouse SCD3, that synthesize oleate and palmitoleate, respectively. We demonstrate that hepatic de novo synthesized oleate, but not palmitoleate, stimulate hepatic lipid accumulation and adiposity, reversing the protective effect of the global SCD1 knockout under lipogenic conditions. Unexpectedly, the accumulation of hepatic lipid occurred without induction of the hepatic DNL program. Changes in hepatic lipid composition were reflected in plasma and in adipose tissue. Importantly, endogenously synthesized hepatic oleate was associated with suppressed DNL and fatty acid oxidation in white adipose tissue. Regression analysis revealed a strong correlation between adipose tissue lipid fuel utilization and hepatic and adipose tissue lipid storage. These data suggest an extrahepatic mechanism where endogenous hepatic oleate regulates lipid homeostasis in adipose tissues.

  9. Hydrogen oxidation on gold electrode in perchloric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Sustersic, M.G.; Almeida, N.V.; Von Mengershausen, A.E. [Facultad de Ingenieria y Ciencias Economico Sociales, Universidad Nacional de San Luis, 25 de Mayo N 384, 5730 Villa Mercedes, San Luis (Argentina)

    2010-06-15

    The aim of this research is to study the interface gold/perchloric acid solution in presence of hydrogen. The reactive is generated by H{sup +} ion reduction and by saturating the electrolyte with the gaseous H{sub 2}. No evidence of H{sub 2} dissociative adsorption is found. In special conditions, a strongly adsorbed layer is formed from the atoms diffusing from inside of the metal. The mass transport occurs in three ways: the diffusion of H atoms inwards, the diffusion of H atoms back to the surface and the dissolved H{sub 2} diffusion from the bulk electrolyte to the surface. When dissolved H{sub 2} reacts, the reaction is kinetically controlled when the H{sub 2} partial pressure is high, and it is diffusionally controlled when the reactive partial pressure is low. Above 0.7 V, (measured vs. RHE), the (100) plane surface reconstruction lifts, and the rate determining step is the H diffusion towards inside of the metal, and the current suddenly falls. The Hydrogen redox reaction on gold shows reversibility with respect to the potential when the reactives are the H diffusing outwards of the metal and the H{sup +} ion present in the electrolyte. However, the absolute current values of oxidation and reduction are different because the reactive sources are different. (author)

  10. O/M ratio measurement in pure and mixed oxide fuels - where are we now?

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.; Chidester, K.; Thompson, M. [Los Alamos National Lab., NM (United States)

    2001-07-01

    The scale-down in the US and Russian nuclear weapons stockpiles has produced a surplus of weapons grade plutonium and highly enriched uranium. The incorporation into mixed-oxide fuel (MOX) is one of the currently favored routes for surplus weapons-grade plutonium. The use of MOX as a nuclear reactor fuel is well established, particularly in Europe and Japan but not in the US. The primary purpose of this investigation was to evaluate existing analytical techniques for their applicability to O/M (oxygen-to-metal ratio) measurements of MOX derived from excess weapons plutonium. The second objective of this investigation was to bring up-to-date the literature on O/M measurement methods, which has not been undertaken in over 20 years. There are several classification schemes that can be used to organize O/M measurement methods. The most popular schemes are based on (a) whether the analysis is performed in solution (wet chemical) or on solid material (dry), and (b) whether the concentration of major constituents are analyzed directly (direct) or are inferred (indirect). Solid state coulometric titration is currently used extensively in studies of phase equilibria, defect chemistry, thermochemical measurement of oxides, including ferrites. Regardless of which indirect method is used (solid state coulometric titration or thermogravimetry), a primary, direct method will also be required for the establishment of the MO{sub 2} reference state, determination of method bias, and periodic calibration. It was recommended that the following direct method be adapted for this purpose: oxygen measurement by inert gas fusion/carbon reduction, and total U, Pu by controlled potential coulometry. In a table are listed the experimental values of accuracy for about 30 O/M methods. (A.C.)

  11. Phase relations and ionic transport behaviour in new mixed oxides of ceria–zirconia–gadolinia

    Energy Technology Data Exchange (ETDEWEB)

    Anithakumari, P.; Grover, V., E-mail: vinita@barc.gov.in; Tyagi, A.K.

    2015-10-25

    The present study investigates structure and the phase relations observed in complex oxide systems obtained by substituting Gd{sub 2}O{sub 3} in the mixed oxide (Ce{sub 0.8}Zr{sub 0.2})O{sub 2}. The X-ray diffraction studies performed on this system revealed two single-phasic phase-fields; fluorite-type (F-type) and C-type. The transformation from F-type to C-type structure was observed at 60 mol% Gd{sup 3+} substitution. The Raman spectroscopic studies, however, reveal further fine structural insights wherein the F-type region was observed only up to 30 mol% of Gd{sup 3+} which was followed by the co-existence of C-type ordered region and F-type region. The single-phasic C-type phase-field was observed only beyond 80 mol% Gd{sup 3+}-substitution. The AC impedance analysis revealed minimum in the activation energy and maximum in ionic conductivity values as a function of Gd{sup 3+}-content. An antagonistic interplay of activation energy and pre-exponential factor is explained as the major factor behind this behaviour. The determination of migration and association energies supported the trend observed in the ionic conductivity values as a function of Gd{sup 3+}-content. The activation energies for hopping are in good agreement with migration activation energies thus establishing that the conduction mechanism involved hopping of oxygen ions. - Highlights: • Presence of single-phasic F- and C-type phases was revealed by XRD studies. • Both, inter-anionic repulsions and ionic sizes governed the lattice parameters. • C-type micro domains in F-type region and vice versa observed by Raman spectra. • High conductivity of 30% Gd{sup 3+} doped sample agrees with low association energy. • Similar migration and hopping energies reveal the hopping mechanism for conduction.

  12. Fasting rapidly increases fatty acid oxidation in white adipose tissue of young broiler chickens.

    Science.gov (United States)

    Torchon, Emmanuelle; Ray, Rodney; Hulver, Matthew W; McMillan, Ryan P; Voy, Brynn H

    2017-01-02

    Upregulating the fatty acid oxidation capacity of white adipose tissue in mice protects against diet-induced obesity, inflammation and insulin resistance. Part of this capacity results from induction of brown-like adipocytes within classical white depots, making it difficult to determine the oxidative contribution of the more abundant white adipocytes. Avian genomes lack a gene for uncoupling protein 1 and are devoid of brown adipose cells, making them a useful model in which to study white adipocyte metabolism in vivo. We recently reported that a brief (5 hour) period of fasting significantly upregulated many genes involved in mitochondrial and peroxisomal fatty acid oxidation pathways in white adipose tissue of young broiler chickens. The objective of this study was to determine if the effects on gene expression manifested in increased rates of fatty acid oxidation. Abdominal adipose tissue was collected from 21 day-old broiler chicks that were fasted for 3, 5 or 7 hours or fed ad libitum (controls). Fatty acid oxidation was determined by measuring and summing (14)CO2 production and (14)C-labeled acid-soluble metabolites from the oxidation of [1-(14)C] palmitic acid. Fasting induced a progressive increase in complete fatty acid oxidation and citrate synthase activity relative to controls. These results confirm that fatty acid oxidation in white adipose tissue is dynamically controlled by nutritional status. Identifying the underlying mechanism may provide new therapeutic targets through which to increase fatty acid oxidation in situ and protect against the detrimental effects of excess free fatty acids on adipocyte insulin sensitivity.

  13. An experimental study of perovskite-structured mixed ionic- electronic conducting oxides and membranes

    Science.gov (United States)

    Zeng, Pingying

    In recent decades, ceramic membranes based on mixed ionic and electronic conducting (MIEC) perovskite-structured oxides have received many attentions for their applications for air separation, or as a membrane reactor for methane oxidation. While numerous perovskite oxide materials have been explored over the past two decades; there are hardly any materials with sufficient practical economic value and performance for large scale applications, which justifies continuing the search for new materials. The main purposes of this thesis study are: (1) develop several novel SrCoO3-delta based MIEC oxides, SrCoCo1-xMxO3-delta, based on which membranes exhibit excellent oxygen permeability; (2) investigate the significant effects of the species and concentration of the dopants M (metal ions with fixed valences) on the various properties of these membranes; (3) investigate the significant effects of sintering temperature on the microstructures and performance of oxygen permeation membranes; and (4) study the performance of oxygen permeation membranes as a membrane reactor for methane combustion. To stabilize the cubic phase structure of the SrCoO3-delta oxide, various amounts of scandium was doped into the B-site of SrCoO 3-delta to form a series of new perovskite oxides, SrScxCoCo 1-xO3-delta (SSCx, x = 0-0.7). The significant effects of scandium-doping concentration on the phase structure, electrical conductivity, sintering performance, thermal and structural stability, cathode performance, and oxygen permeation performance of the SSCx membranes, were systematically studied. Also for a more in-depth understanding, the rate determination steps for the oxygen transport process through the membranes were clarified by theoretical and experimental investigation. It was found that only a minor amount of scandium (5 mol%) doping into the B-site of SrCoO3-delta can effectively stabilize the cubic phase structure, and thus significantly improve the electrical conductivity and

  14. Transformation of Unsaturated Fatty Acids/Esters to Corresponding Keto Fatty Acids/Esters by Aerobic Oxidation with Pd(II)/Lewis Acid Catalyst.

    Science.gov (United States)

    Senan, Ahmed M; Zhang, Sicheng; Zeng, Miao; Chen, Zhuqi; Yin, Guochuan

    2017-08-16

    Utilization of renewable biomass to partly replace the fossil resources in industrial applications has attracted attention due to the limited fossil feedstock with the increased environmental concerns. This work introduced a modified Wacker-type oxidation for transformation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, in which Cu(2+) cation was replaced with common nonredox metal ions, that is, a novel Pd(II)/Lewis acid (LA) catalyst. It was found that adding nonredox metal ions can effectively promote Pd(II)-catalyzed oxidation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, even much better than Cu(2+), and the promotional effect is highly dependent on the Lewis acidity of added nonredox metal ions. The improved catalytic efficiency is attributed to the formation of heterobimetallic Pd(II)/LA species, and the oxidation mechanism of this Pd(II)/LA catalyst is also briefly discussed.

  15. Molten salt oxidation of mixed wastes: Separation of radioactive materials and Resource Conservation and Recovery Act (RCRA) materials

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.T.; Haas, P.A.; Rudolph, J.C.

    1993-12-01

    The Oak Ridge National Laboratory (ORNL) is involved in a program to apply a molten salt oxidation (MSO) process to the treatment of mixed wastes at Oak Ridge and other Department of Energy (DOE) sites. Mixed wastes are defined as those wastes that contain both radioactive components, which are regulated by the atomic energy legislation, and hazardous waste components, which are regulated under the Resource Conservation and Recovery Act (RCRA). A major part of our ORNL program involves the development of separation technologies that are necessary for the complete treatment of mixed wastes. The residues from the MSO treatment of the mixed wastes must be processed further to separate the radioactive components, to concentrate and recycle residues, or to convert the residues into forms acceptable for final disposal. This paper is a review of the MSO requirements for separation technologies, the information now available, and the concepts for our development studies.

  16. Culturing oil sands microbes as mixed species communities enhances ex situ model naphthenic acid degradation.

    Science.gov (United States)

    Demeter, Marc A; Lemire, Joseph A; Yue, Gordon; Ceri, Howard; Turner, Raymond J

    2015-01-01

    Oil sands surface mining for bitumen results in the formation of oil sands process water (OSPW), containing acutely toxic naphthenic acids (NAs). Potential exists for OSPW toxicity to be mitigated by aerobic degradation of the NAs by microorganisms indigenous to the oil sands tailings ponds, the success of which is dependent on the methods used to exploit the metabolisms of the environmental microbial community. Having hypothesized that the xenobiotic tolerant biofilm mode-of-life may represent a feasible way to harness environmental microbes for ex situ treatment of OSPW NAs, we aerobically grew OSPW microbes as single and mixed species biofilm and planktonic cultures under various conditions for the purpose of assaying their ability to tolerate and degrade NAs. The NAs evaluated were a diverse mixture of eight commercially available model compounds. Confocal microscopy confirmed the ability of mixed and single species OSPW cultures to grow as biofilms in the presence of the NAs evaluated. qPCR enumeration demonstrated that the addition of supplemental nutrients at concentrations of 1 g L(-1) resulted in a more numerous population than 0.001 g L(-1) supplementation by approximately 1 order of magnitude. GC-FID analysis revealed that mixed species cultures (regardless of the mode of growth) are the most effective at degrading the NAs tested. All constituent NAs evaluated were degraded below detectable limits with the exception of 1-adamantane carboxylic acid (ACA); subsequent experimentation with ACA as the sole NA also failed to exhibit degradation of this compound. Single species cultures degraded select few NA compounds. The degradation trends highlighted many structure-persistence relationships among the eight NAs tested, demonstrating the effect of side chain configuration and alkyl branching on compound recalcitrance. Of all the isolates, the Rhodococcus spp. degraded the greatest number of NA compounds, although still less than the mixed species cultures

  17. Photocatalytic oxidation of humic acid and its effect on haloacetic acid formation potential: a fluorescence spectrometry study.

    Science.gov (United States)

    Xiaoju, Yan; Ruiling, Bao; Shuili, Yu; Qiongfang, Li; Wei, Chen

    2012-01-01

    By fluorescence spectrometry method, molecular conformation changes of humic acid (HA) during the photocatalytic oxidation process were studied. Haloacetic acids formation potential (HAAFP) changes during the oxidation process were also measured. The results indicated that aromatic rings of HA decreased and conjugated double bonds were destroyed at the beginning of the process. Meanwhile, organic matter with large molecular weight decomposed into intermediates with smaller molecular weight, such as tryptophan and tyrosine. HA can be degraded almost completely, but not be mineralized thoroughly. Structures of the intermediates were changing during the oxidation process. Molecular structure transformation of HA led to the fluctuation tendency of the HAAFP changes during the photocatalytic oxidation process. HAAFP increased to 1.22 times that in raw water after 30 min of ultraviolet (UV) radiation, and decreased to 0.66 times that in raw water after 60 min of photocatalytic oxidation.

  18. Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Frei, B. (Department of Nutrition, Harvard School of Public Health, Boston, MA (Unites States))

    1991-12-01

    The authors exposed human blood plasma and low-density lipoprotein (LDL) to many different oxidative challenges and followed the temporal consumption of endogenous antioxidants in relation to the initiation of oxidative damage. Under all types of oxidizing conditions, ascorbic acid completely protects lipids in plasma and LDL against detectable peroxidative damage as assessed by a specific and highly sensitive assay for lipid peroxidation. Ascorbic acid proved to be superior to the other water-soluble plasma antioxidants bilirubin, uric acid, and protein thiols as well as to the lipoprotein-associated antioxidants alpha-tocopherol, ubiquinol-10, lycopene, and beta-carotene. Although these antioxidants can lower the rate of detectable lipid peroxidation, they are not able to prevent its initiation. Only ascorbic acid is reactive enough to effectively intercept oxidants in the aqueous phase before they can attack and cause detectable oxidative damage to lipids.

  19. Micelle-assisted signaling of peracetic acid by the oxidation of pyreneboronic acid via monomer-excimer switching.

    Science.gov (United States)

    Choi, Jiyoung; Lee, Hyo Jin; Cho, Min Jeoung; Chang, Suk-Kyu

    2015-08-15

    A simple fluorescent probe for the industrial oxidant peracetic acid (PAA) was investigated. PAA-assisted oxidative conversion of pyrene-1-boronic acid into 1-hydroxypyrene was used as the signaling tool. Pyreneboronic acid was found to display selective signaling behavior, being more responsive to PAA than to other commonly used practical oxidants such as H2O2 and HOCl. The changes in pyrene monomer fluorescence to excimer were used in the quantitative analysis of PAA. When using the surfactant hexadecyltrimethylammonium bromide as a micellar additive, the signaling of PAA was markedly enhanced. Selective fluorescence signaling of PAA by pyrene-1-boronic acid with a detection limit of 1.5×10(-6)M in aqueous environment was successfully achieved.

  20. In vitro studies on the oxidation of medium-chain dicarboxylic acids in rat liver.

    Science.gov (United States)

    Kølvraa, S; Gregersen, N

    1986-05-21

    The degradation of medium-chained dicarboxylic (DC) acids was investigated on purified mitochondria and peroxisomes. Intact organelles were incubated with dodecanedioic acid (DC12), suberic acid (DC8) and adipic acid (DC6), and the production of lower-chained DC-acids and of acetyl-CoA + acetyl-carnitine was monitored. It was shown, that intact peroxisomes could beta-oxidize DC12, DC10, and DC8 at least as far as DC6, while intact mitochondria readily beta-oxidized DC12, and DC10 as far as succinic acid. DC8 and DC6 were not oxidized by intact mitochondria when these two acids were presented externally to the intact organelle. When they were formed intramitochondrially from DC12 and DC10, both DC8 and DC6 were, however, to a great extent beta-oxidized as far as succinic acid. The major reason for this difference between mitochondrial oxidation of externally and internally located DC8 and DC6 seems to be an inability to transport these two acids through the mitochondrial membrane. For DC12 and DC10, the mitochondrial transport systems, which were indicated to be identical to the systems used by the corresponding monocarboxylic acids, were found to be rate-limiting in the beta-oxidation of these acids. A contributing factor to the undetectable beta-oxidation of externally located DC8 and DC6 may also be, that the Km values of DC8-CoA (460 +/- 70 mumol/l) and DC6-CoA (980 +/- 90 mumol/l) towards the acyl-CoA dehydrogenases are very high. These results imply that very high concentrations of intermediates are created intramitochondrially during beta-oxidation, concentrations which are probably only formed through formation of DC8-CoA and DC6-CoA from longer DC-acids and not by transport from outside the mitochondria. The data presented thus for the first time give evidence to a pathway for medium-chained monocarboxylic acids (especially lauric acid and decanoic acid) through cytosolic omega-oxidation followed by activation, transport over the mitochondrial membrane and

  1. Pluronic-poly (acrylic acid)-cysteine/Pluronic L121 mixed micelles improve the oral bioavailability of paclitaxel.

    Science.gov (United States)

    Zhao, Yanli; Li, Yanli; Ge, Jianjun; Li, Na; Li, Ling-Bing

    2014-11-01

    The aim of the study is to synthesize a thiolated Pluronic copolymer, Pluronic-poly (acrylic acid)-cysteine copolymer, to construct a mixed micelle system with the Pluronic-poly (acrylic acid)-cysteine copolymer and Pluronic L121 (PL121) and to evaluate the potential of these mixed micelles as an oral drug delivery system for paclitaxel. Compared with Pluronic-poly (acrylic acid)-cysteine micelles, drug-loading capacity of Pluronic-poly (acrylic acid)-cysteine/PL121 mixed micelles was increased from 0.4 to 2.87%. In vitro release test indicated that Pluronic-poly (acrylic acid)-cysteine/PL121 mixed micelles exhibited a pH sensitivity. The permeability of drug-loaded micelles in the intestinal tract was studied with an in situ perfusion method in rats. The presence of verapamil and Pluronic both improved the intestinal permeability of paclitaxel, which further certified the inhibition effect of thiolated Pluronic on P-gp. In pharmacokinetic study, the area under the plasma concentration-time curve (AUC0→∞) of paclitaxel-loaded mixed micelles was four times greater than that of the paclitaxel solution (p cysteine/PL121 micelles were proven to be a potential oral drug delivery system for paclitaxel.

  2. Method of CO and/or CO.sub.2 hydrogenation using doped mixed-metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Shekhawat, Dushyant; Berry, David A.; Haynes, Daniel J.; Abdelsayed, Victor; Smith, Mark W.; Spivey, James J.

    2015-10-06

    A method of hydrogenation utilizing a reactant gas mixture comprising a carbon oxide and a hydrogen agent, and a hydrogenation catalyst comprising a mixed-metal oxide containing metal sites supported and/or incorporated into the lattice. The mixed-metal oxide comprises a perovskite, a pyrochlore, a fluorite, a brownmillerite, or mixtures thereof doped at the A-site or the B-site. The metal site may comprise a deposited metal, where the deposited metal is a transition metal, an alkali metal, an alkaline earth metal, or mixtures thereof. Contact between the carbon oxide, hydrogen agent, and hydrogenation catalyst under appropriate conditions of temperature, pressure and gas flow rate generate a hydrogenation reaction and produce a hydrogenated product made up of carbon from the carbon oxide and some portion of the hydrogen agent. The carbon oxide may be CO, CO.sub.2, or mixtures thereof and the hydrogen agent may be H.sub.2. In a particular embodiment, the hydrogenated product comprises an alcohol, an olefin, an aldehyde, a ketone, an ester, an oxo-product, or mixtures thereof.

  3. Method of CO and/or CO.sub.2 hydrogenation to higher hydrocarbons using doped mixed-metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Shekhawat, Dushyant; Berry, David A.; Haynes, Daniel J.; Abdelsayed, Victor; Smith, Mark W.; Spivey, James J.

    2017-03-21

    A method of hydrogenation utilizing a reactant gas mixture comprising a carbon oxide and a hydrogen agent, and a hydrogenation catalyst comprising a mixed-metal oxide containing metal sites supported and/or incorporated into the lattice. The mixed-metal oxide comprises a pyrochlore, a brownmillerite, or mixtures thereof doped at the A-site or the B-site. The metal site may comprise a deposited metal, where the deposited metal is a transition metal, an alkali metal, an alkaline earth metal, or mixtures thereof. Contact between the carbon oxide, hydrogen agent, and hydrogenation catalyst under appropriate conditions of temperature, pressure and gas flow rate generate a hydrogenation reaction and produce a hydrogenated product made up of carbon from the carbon oxide and some portion of the hydrogen agent. The carbon oxide may be CO, CO.sub.2, or mixtures thereof and the hydrogen agent may be H.sub.2. In a particular embodiment, the hydrogenated product comprises olefins, paraffins, or mixtures thereof.

  4. The Use of Ascorbate as an Oxidation Inhibitor in Prebiotic Amino Acid Synthesis: A Cautionary Note

    Science.gov (United States)

    Kuwahara, Hideharu; Eto, Midori; Kawamoto, Yukinori; Kurihara, Hironari; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei

    2012-12-01

    It is generally thought that the terrestrial atmosphere at the time of the origin of life was CO2-rich and that organic compounds such as amino acids would not have been efficiently formed abiotically under such conditions. It has been pointed out, however, that the previously reported low yields of amino acids may have been partially due to oxidation by nitrite/nitrate during acid hydrolysis. Specifically, the yield of amino acids was found to have increased significantly (by a factor of several hundred) after acid hydrolysis with ascorbic acid as an oxidation inhibitor. However, it has not been shown that CO2 was the carbon source for the formation of the amino acids detected after acid hydrolysis with ascorbic acid. We therefore reinvestigated the prebiotic synthesis of amino acids in a CO2-rich atmosphere using an isotope labeling experiment. Herein, we report that ascorbic acid does not behave as an appropriate oxidation inhibitor, because it contributes amino acid contaminants as a consequence of its reactions with the nitrogen containing species and formic acid produced during the spark discharge experiment. Thus, amino acids are not efficiently formed from a CO2-rich atmosphere under the conditions studied.

  5. The use of ascorbate as an oxidation inhibitor in prebiotic amino acid synthesis: a cautionary note.

    Science.gov (United States)

    Kuwahara, Hideharu; Eto, Midori; Kawamoto, Yukinori; Kurihara, Hironari; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei

    2012-12-01

    It is generally thought that the terrestrial atmosphere at the time of the origin of life was CO(2)-rich and that organic compounds such as amino acids would not have been efficiently formed abiotically under such conditions. It has been pointed out, however, that the previously reported low yields of amino acids may have been partially due to oxidation by nitrite/nitrate during acid hydrolysis. Specifically, the yield of amino acids was found to have increased significantly (by a factor of several hundred) after acid hydrolysis with ascorbic acid as an oxidation inhibitor. However, it has not been shown that CO(2) was the carbon source for the formation of the amino acids detected after acid hydrolysis with ascorbic acid. We therefore reinvestigated the prebiotic synthesis of amino acids in a CO(2)-rich atmosphere using an isotope labeling experiment. Herein, we report that ascorbic acid does not behave as an appropriate oxidation inhibitor, because it contributes amino acid contaminants as a consequence of its reactions with the nitrogen containing species and formic acid produced during the spark discharge experiment. Thus, amino acids are not efficiently formed from a CO(2)-rich atmosphere under the conditions studied.

  6. Nitrous acid in a street canyon environment: Sources and contributions to local oxidation capacity

    Science.gov (United States)

    Yun, Hui; Wang, Zhe; Zha, Qiaozhi; Wang, Weihao; Xue, Likun; Zhang, Li; Li, Qinyi; Cui, Long; Lee, Shuncheng; Poon, Steven C. N.; Wang, Tao

    2017-10-01

    Nitrous acid (HONO) plays an important role in radical formation and photochemical oxidation processes in the boundary layer. However, its impact on the chemistry in a street canyon microenvironment has not been thoroughly investigated. In this study, we measured HONO in a street canyon in urban Hong Kong and used an observation-based box model (OBM) with the Master Chemical Mechanism (MCM v3.3.1) to investigate the contribution of HONO to local oxidation chemistry. The observed HONO mixing ratios were in the range of 0.4-13.9 ppbv, with an average of 3.91 ppbv in the daytime and 2.86 ppbv at night. A mean HONO/NOx emission ratio of 1.0% (±0.5%) from vehicle traffic was derived. OBM simulations constrained by the observed HONO showed that the maximum concentrations of OH, HO2, and RO2 reached 4.65 × 106, 4.40 × 106, and 1.83 × 106 molecules cm-3, which were 7.9, 5.0, and 7.5 times, respectively, the results in the case without HONO constrained. Photolysis of HONO contributed to 86.5% of the total primary radical production rates and led to efficient NO2 and O3 production under the condition of weak regional transport of O3. The formation of HNO3 contributed to 98.4% of the total radical termination rates. Our results suggest that HONO could significantly increase the atmospheric oxidation capacity in a street canyon and enhance the secondary formation of HNO3 and HCHO, which can damage outdoor building materials and pose health risks to pedestrians.

  7. Overexpression of Fatty-Acid-β-Oxidation-Related Genes Extends the Lifespan of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Shin-Hae Lee

    2012-01-01

    Full Text Available A better understanding of the aging process is necessary to ensure that the healthcare needs of an aging population are met. With the trend toward increased human life expectancies, identification of candidate genes affecting the regulation of lifespan and its relationship to environmental factors is essential. Through misexpression screening of EP mutant lines, we previously isolated several genes extending lifespan when ubiquitously overexpressed, including the two genes encoding the fatty-acid-binding protein and dodecenoyl-CoA delta-isomerase involved in fatty-acid β-oxidation, which is the main energy resource pathway in eukaryotic cells. In this study, we analyzed flies overexpressing the two main components of fatty-acid β-oxidation, and found that overexpression of fatty-acid-β-oxidation-related genes extended the Drosophila lifespan. Furthermore, we found that the ability of dietary restriction to extend lifespan was reduced by the overexpression of fatty-acid-β-oxidation-related genes. Moreover, the overexpression of fatty-acid-β-oxidation-related genes enhanced stress tolerance to oxidative and starvation stresses and activated the dFOXO signal, indicating translocation to the nucleus and transcriptional activation of the dFOXO target genes. Overall, the results of this study suggest that overexpression of fatty-acid-β-oxidation-related genes extends lifespan in a dietary-restriction-related manner, and that the mechanism of this process may be related to FOXO activation.

  8. Melting behavior of (Th,U)O2 and (Th,Pu)O2 mixed oxides

    Science.gov (United States)

    Ghosh, P. S.; Kuganathan, N.; Galvin, C. O. T.; Arya, A.; Dey, G. K.; Dutta, B. K.; Grimes, R. W.

    2016-10-01

    The melting behaviors of pure ThO2, UO2 and PuO2 as well as (Th,U)O2 and (Th,Pu)O2 mixed oxides (MOX) have been studied using molecular dynamics (MD) simulations. The MD calculated melting temperatures (MT) of ThO2, UO2 and PuO2 using two-phase simulations, lie between 3650-3675 K, 3050-3075 K and 2800-2825 K, respectively, which match well with experiments. Variation of enthalpy increments and density with temperature, for solid and liquid phases of ThO2, PuO2 as well as the ThO2 rich part of (Th,U)O2 and (Th,Pu)O2 MOX are also reported. The MD calculated MT of (Th,U)O2 and (Th,Pu)O2 MOX show good agreement with the ideal solidus line in the high thoria section of the phase diagram, and evidence for a minima is identified around 5 atom% of ThO2 in the phase diagram of (Th,Pu)O2 MOX.

  9. Low-Frequency Mechanical Spectroscopy of Lanthanum Cobaltite Based Mixed Conducting Oxides

    Directory of Open Access Journals (Sweden)

    Wu Xiu Sheng

    2016-09-01

    Full Text Available The low-frequency mechanical spectra of lanthanum cobaltite based mixed conducting oxides have been measured using a computer-controlled inverted torsion pendulum. The results indicate that the internal friction spectra and shear modulus depend on the Sr doping contents (x. For undoped samples, no internal friction peak is observed. However, for La0.8Sr0.2CoO3‒δ, three internal friction peaks (P2, P3 and P4 are observed. In addition to these peaks, two more peaks (P0 and P1 are observed in La0.6Sr0.4CoO3‒δ. The P0 and P1 peaks show characteristics of a phase transition, while the P2, P3 and P4 peaks are of relaxation-type. Our analysis suggests that the P0 peak is due to a phase separation and the P1 peak is related to the ferromagnetic–paramagnetic phase transition. The P2, P3 and P4 peaks are associated with the motion of domain walls. The formation of this kind of domain structure is a consequence of a transformation from the paraelastic cubic phase to the ferroelastic rhombohedral phase. With partial substitution of Fe for Co, only one peak is observed, which is discussed as a result of different microstructure.

  10. O/M RATIO MEASUREMENT IN PURE AND MIXED OXIDE FULES - WHERE ARE WE NOW?

    Energy Technology Data Exchange (ETDEWEB)

    J. RUBIN; ET AL

    2000-12-01

    The oxygen-to-metal (O/M) ratio is one of the most critical parameters of nuclear fuel fabrication, and its measurement is closely monitored for manufacturing process control and to ensure the service behavior of the final product. Thermogravimetry is the most widely used method, the procedure for which has remained largely unchanged since its development some thirty years ago. It was not clear to us, however, that this method is still the optimum one in light of advances in instrumentation, and in the current regulatory environment, particularly with regard to waste management and disposal. As part of the MOX fuel fabrication program at Los Alamos, we conducted a comprehensive review of methods for O/M measurements in UO{sub 2}, PuO{sub 2} and mixed oxide fuels for thermal reactors. A concerted effort was made to access information not available in the open literature. We identified approximately thirty five experimental methods that (a) have been developed with the intent of measuring O/M, (b) provided O/M indirectly by suitable reduction of the measured data, or (c) could provide O/M data with suitable data reduction or when combined with other methods. We will discuss the relative strengths and weaknesses of these methods in their application to current routine and small-lot production environment.

  11. Integrated demonstration of molten salt oxidation with salt recycle for mixed waste treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, P.C.

    1997-11-01

    Molten Salt Oxidation (MSO) is a thermal, nonflame process that has the inherent capability of completely destroying organic constituents of mixed wastes, hazardous wastes, and energetic materials while retaining inorganic and radioactive constituents in the salt. For this reason, MSO is considered a promising alternative to incineration for the treatment of a variety of organic wastes. Lawrence Livermore National Laboratory (LLNL) has prepared a facility and constructed an integrated pilot-scale MSO treatment system in which tests and demonstrations are performed under carefully controlled (experimental) conditions. The system consists of a MSO processor with dedicated off-gas treatment, a salt recycle system, feed preparation equipment, and equipment for preparing ceramic final waste forms. This integrated system was designed and engineered based on laboratory experience with a smaller engineering-scale reactor unit and extensive laboratory development on salt recycle and final forms preparation. In this paper we present design and engineering details of the system and discuss its capabilities as well as preliminary process demonstration data. A primary purpose of these demonstrations is identification of the most suitable waste streams and waste types for MSO treatment.

  12. Percolation Theory in Solid Oxide Fuel Cell Composite Electrodes with a Mixed Electronic and Ionic Conductor

    Directory of Open Access Journals (Sweden)

    Meng Ni

    2013-03-01

    Full Text Available Percolation theory is generalized to predict the effective properties of specific solid oxide fuel cell composite electrodes, which consist of a pure ion conducting material (e.g., YSZ or GDC and a mixed electron and ion conducting material (e.g., LSCF, LSCM or CeO2. The investigated properties include the probabilities of an LSCF particle belonging to the electron and ion conducting paths, percolated three-phase-boundary electrochemical reaction sites, which are based on different assumptions, the exposed LSCF surface electrochemical reaction sites and the revised expressions for the inter-particle ionic conductivities among LSCF and YSZ materials. The effects of the microstructure parameters, such as the volume fraction of the LSCF material, the particle size distributions of both the LSCF and YSZ materials (i.e., the mean particle radii and the non-dimensional standard deviations, which represent the particle size distributions and the porosity are studied. Finally, all of the calculated results are presented in non-dimensional forms to provide generality for practical application. Based on these results, the relevant properties can be easily evaluated, and the microstructure parameters and intrinsic properties of each material are specified.

  13. Luminescence studies of rare earth doped yttrium gadolinium mixed oxide phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Som, S.; Choubey, A. [Department of Applied Physics, Indian School of Mines, Dhanbad, Jharkhand 826004 (India); Sharma, S.K., E-mail: sksharma_ism@yahoo.co.in [Department of Applied Physics, Indian School of Mines, Dhanbad, Jharkhand 826004 (India)

    2012-09-01

    This paper reports the photoluminescence and thermoluminescence properties of gamma ray induced rare earth doped yttrium gadolinium mixed oxide phosphor. The europium (Eu{sup 3+}) was used as rare earth dopant. The phosphor was prepared by chemical co-precipitation method according to the formula (Y{sub 2-x-y}Gd{sub x}) O{sub 3}: Eu{sub y}{sup 3+} (x=0.5; y=0.05). The photoluminescence emission spectrum of the prepared phosphor shows intense peaks in the red region at 615 nm for {sup 5}D{sub 0}{yields}{sup 7}F{sub 2} transitions and the photoluminescence excitation spectra show a broad band located around 220-270 nm for the emission wavelength fixed at 615 nm. The thermoluminescence studies were carried out after irradiating the phosphor by gamma rays in the dose range from 100 Gy to 1 KGy. In the thermoluminescence glow curves, one single peak was observed at about 300 Degree-Sign C of which the intensity increases linearly in the studied dose range of gamma rays. The glow peak was deconvoluted by GlowFit program and the kinetic parameters associated with the deconvoluted peaks were calculated. The kinetic parameters were also calculated by various glow curve shape and heating rate methods.

  14. Luminescence studies of rare earth doped yttrium gadolinium mixed oxide phosphor

    Science.gov (United States)

    Som, S.; Choubey, A.; Sharma, S. K.

    2012-09-01

    This paper reports the photoluminescence and thermoluminescence properties of gamma ray induced rare earth doped yttrium gadolinium mixed oxide phosphor. The europium (Eu3+) was used as rare earth dopant. The phosphor was prepared by chemical co-precipitation method according to the formula (Y2-x-yGdx) O3: Euy3+ (x=0.5; y=0.05). The photoluminescence emission spectrum of the prepared phosphor shows intense peaks in the red region at 615 nm for 5D0→7F2 transitions and the photoluminescence excitation spectra show a broad band located around 220-270 nm for the emission wavelength fixed at 615 nm. The thermoluminescence studies were carried out after irradiating the phosphor by gamma rays in the dose range from 100 Gy to 1 KGy. In the thermoluminescence glow curves, one single peak was observed at about 300 °C of which the intensity increases linearly in the studied dose range of gamma rays. The glow peak was deconvoluted by GlowFit program and the kinetic parameters associated with the deconvoluted peaks were calculated. The kinetic parameters were also calculated by various glow curve shape and heating rate methods.

  15. Decommissioning of a mixed oxide fuel fabrication plant at Winfrith Technolgy Centre

    Energy Technology Data Exchange (ETDEWEB)

    Pengelly, M.G.A. [AEA Technology, Dorchester (United Kingdom)

    1994-01-01

    The Alpha Materials Laboratory (Building A52) at Winfrith contained a mixed oxide fuel fabrication plant which had a capability of producing 10 te/yr of pelleted/compacted fuel and was in operation from 1962 until 1980, when the requirement for this type of fuel in the UK diminished, and the plant became surplus to requirements. A program to develop decommissioning techniques for plutonium plants was started in 1983, addressing the following aspects of alpha plant decommissioning: (1) Re-usable containment systems, (2) Strippable coating technology, (3) Mobile air filtration plant, (4) Size reduction primarily using cold cutting, (5) techniques, (6) Waste packing, and (7) Alpha plant decommissioning methodology. The technology developed has been used to safely and efficiently decommission radioactive plant and equipment including Pu contaminated glove boxes. (63 glove boxes to date) The technology has been widely adopted in the United Kingdom and elsewhere. This paper outlines the general strategies adopted and techniques used for glove box decommissioning in building A52.

  16. Survey of Worldwide Light Water Reactor Experience with Mixed Uranium-Plutonium Oxide Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Cowell, B.S.; Fisher, S.E.

    1999-02-01

    The US and the Former Soviet Union (FSU) have recently declared quantities of weapons materials, including weapons-grade (WG) plutonium, excess to strategic requirements. One of the leading candidates for the disposition of excess WG plutonium is irradiation in light water reactors (LWRs) as mixed uranium-plutonium oxide (MOX) fuel. A description of the MOX fuel fabrication techniques in worldwide use is presented. A comprehensive examination of the domestic MOX experience in US reactors obtained during the 1960s, 1970s, and early 1980s is also presented. This experience is described by manufacturer and is also categorized by the reactor facility that irradiated the MOX fuel. A limited summary of the international experience with MOX fuels is also presented. A review of MOX fuel and its performance is conducted in view of the special considerations associated with the disposition of WG plutonium. Based on the available information, it appears that adoption of foreign commercial MOX technology from one of the successful MOX fuel vendors will minimize the technical risks to the overall mission. The conclusion is made that the existing MOX fuel experience base suggests that disposition of excess weapons plutonium through irradiation in LWRs is a technically attractive option.

  17. Synthesis and Characterization of K-Ta Mixed Oxides for Hydrogen Generation in Photocatalysis

    Directory of Open Access Journals (Sweden)

    Beata Zielińska

    2012-01-01

    Full Text Available K-Ta mixed oxides photocatalysts have been prepared by impregnation followed by calcination. The influence of the reaction temperature (450°C–900°C on the phase formation, crystal morphology, and photocatalytic activity in hydrogen generation of the produced materials was investigated. The detailed analysis has revealed that all products exhibit high crystallinity and irregular structure. Moreover, two different crystal structures of potassium tantalates such as KTaO3 and K2Ta4O11 were obtained. It was also found that the sample composed of KTaO3 and traces of unreacted Ta2O5 (annealed at 600°C exhibits the highest activity in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were examined by X-ray diffraction (XRD and diffuse reflectance (DR UV-vis and resonance Raman spectroscopic methods, respectively. Morphology and chemical composition of the produced samples were studied using a high-resolution transmission electron microscope (HR-TEM and an energy dispersive X-ray spectrometer (EDX as its mode.

  18. Thermally induced growth of ZnO nanocrystals on mixed metal oxide surfaces.

    Science.gov (United States)

    Inayat, Alexandra; Makky, Ayman; Giraldo, Jose; Kuhnt, Andreas; Busse, Corinna; Schwieger, Wilhelm

    2014-06-23

    An in situ method for the growth of ZnO nanocrystals on Zn/Al mixed metal oxide (MMO) surfaces is presented. The key to this method is the thermal treatment of Zn/Al layered double hydroxides (Zn/Al LDHs) in the presence of nitrate anions, which results in partial demixing of the LDH/MMO structure and the subsequent crystallization of ZnO crystals on the surface of the forming MMO layers. In a first experimental series, thermal treatment of Zn/Al LDHs with different fractions of nitrate and carbonate in the interlayer space was examined by thermogravimetry coupled with mass spectrometry (TG-MS) and in situ XRD. In a second experimental series, Zn/Al LDHs with only carbonate in the interlayer space were thermally treated in the presence of different amounts of an external nitrate source (NH4NO3). All obtained Zn/Al MMO samples were analysed by electron microscopy, nitrogen physisorption and powder X-ray diffraction. The gas phase formed during nitrate decomposition turned out to be responsible for the formation of crystalline ZnO nanoparticles. Accordingly, both interlayer nitrate and the presence of ammonium nitrate led to the formation of supported ZnO nanocrystals with mean diameters between 100 and 400 nm, and both methods offer the possibility to tailor the amount and size of the ZnO crystals by means of the amount of nitrate.

  19. Impact of acid and oxidative modifications, single or dual, of sorghum starch on biodegradable films.

    Science.gov (United States)

    Biduski, Bárbara; Silva, Francine Tavares da; Silva, Wyller Max da; Halal, Shanise Lisie de Mello El; Pinto, Vania Zanella; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-01-01

    The objective of this study was to evaluate the effects of acid and oxidation modifications on sorghum starch, as well as the effect of dual modification of starch on the physical, morphological, mechanical, and barrier properties of biodegradable films. The acid modification was performed with 3% lactic acid and the oxidation was performed with 1.5% active chlorine. For dual modification, the acid modification was performed first, followed by oxidation under the same conditions as above. Both films of the oxidized starches, single and dual, had increased stiffness, providing a higher tensile strength and lower elongation when compared to films based on native and single acid modified starches. However, the dual modification increased the water vapor permeability of the films without changing their solubility. The increase in sorghum starch concentration in the filmogenic solution increased the thickness, water vapor permeability, and elongation of the films.

  20. Acid rock drainage passive remediation: Potential use of alkaline clay, optimal mixing ratio and long-term impacts.

    Science.gov (United States)

    Plaza, Fernando; Wen, Yipei; Perone, Hanna; Xu, Yi; Liang, Xu

    2017-01-15

    Acid rock drainage (ARD) is one of the most adverse environmental problems of the mining industry. Surface and ground water affected by this pollution are characterized by their acidity and the high content of sulfates and metals/metalloids. In this study, alkaline clay (AC), an industrial waste with a high alkalinity, which is utilized in the alumina refining process, was used as the remediation material to inhibit pyrite oxidation in waste coal piles. Through a series of laboratory experiments (static and kinetic), complemented with field measurements and geochemical modeling, three important issues associated with this passive and sustainable ARD remediation method were investigated: 1) the potential use of alkaline clay as an ARD remediation material, 2) the adequate alkaline clay/coal refuse mixing ratio (AC/CR) to ensure pH values close to neutral conditions, and, 3) the implications for long-term performance, in terms of the trends of the main parameters involved in this process such as pH, concentrations of sulfate, iron and other dissolved contaminants. Both field measurements and the samples used for the experiments came from a local waste coal site. Through the analysis of the field measurements and the outcome of the laboratory experiments, AC proved to be an effective remediation material for ARD. Compared to those found in mine tailings, the concentrations of contaminants such as iron, manganese or sulfate were significantly reduced with this remediation approach. Moreover, results suggest a reliable long-term stability of the remediation (i.e. neutral pH conditions are maintained), thus enhancing the generation of iron precipitates that could produce pyrite grain coating. These processes also made the amended layer less porous, thus increased water retention and hindered oxygen diffusion.