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  1. BDTC - Uma Biblioteca Digital de Trabalhos Científicos com Serviços Integrados

    Directory of Open Access Journals (Sweden)

    Cristiano Roberto Cervi

    2009-09-01

    Full Text Available Este artigo apresenta a BDTC, uma biblioteca digital de trabalhos científicos. A BDTC é composta por um conjunto de serviços que busca atender a algumas necessidades dos usuários. O artigo foca a arquitetura da BDTC, mostrando especificamente os serviços de autoarquivamento de documentos, extração de metadados de arquivos PDF e uso de índices que fornecem suporte à busca por similaridade.

  2. Ternary CoS{sub 2}/MoS{sub 2}/RGO electrocatalyst with CoMoS phase for efficient hydrogen evolution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan-Ru; Shang, Xiao [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Gao, Wen-Kun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Dong, Bin, E-mail: dongbin@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Chi, Jing-Qi; Li, Xiao; Yan, Kai-Li; Chai, Yong-Ming [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Yun-Qi, E-mail: liuyq@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Chen-Guang [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China)

    2017-08-01

    Highlights: • Ternary CoS{sub 2}/MoS{sub 2}/RGO with CoMoS phase as electrocatalyst for HER was prepared. • CoMoS phase have the metallic nature and highly intrinsic activity for HER. • RGO support ensures good distribution of CoMoS phase and enhances the conductivity. • The introduction of CoMoS and RGO may be a novel strategy for efficient HER of MoS{sub 2}. - Abstract: CoMoS phase with metallic character plays crucial role on enhancing the activity of MoS{sub 2} electrocatalysts for hydrogen evolution reaction (HER). However, only Co atoms located in the edges of MoS{sub 2} can create CoMoS phase, so it is a challenge to obtain CoMoS phase with homogeneous distribution limited by the layered MoS{sub 2} and doping method of Co. Herein, we reported a simple one-pot hydrothermal method to prepare novel ternary CoS{sub 2}/MoS{sub 2}/RGO with CoMoS phase for HER using reduced graphene oxide (RGO) as support. XPS proves the formation of CoMoS phase, implying the enhanced activity for HER. RGO support ensures the well distribution of CoMoS phase and enhances the conductivity of CoS{sub 2}/MoS{sub 2}/RGO. Compared to CoS{sub 2}/RGO, MoS{sub 2}/RGO and CoS{sub 2}/MoS{sub 2}, the obtained CoS{sub 2}/MoS{sub 2}/RGO shows superior activity for HER with an onset overpotential of −80 mV (vs. RHE), small Tafel slope of 56 mV dec{sup −1}, high exchange current density of 11.4 μA cm{sup −2} and rigid electrochemical durability. The enhanced performances for HER may be ascribed to the formation of CoMoS phase with high activity and the existence of RGO support with good electrical conductivitys in ternary CoS{sub 2}/MoS{sub 2}/RGO. Therefore, the introduction of CoMoS phase and RGO into MoS{sub 2} could effectively enhance electrocatalytic properties for HER.

  3. Interaction of molybdenum (6) with potassium benzyldithiocarbaminate during amperometric titration

    International Nuclear Information System (INIS)

    Galushko, S.V.; Usatenko, Yu.I.

    1975-01-01

    The paper is an amperometric study of the mechanism of interaction between molybdenum (VI) and potassium benzyl dithiocarbamate [BDTC] which was based on the use of voltamperometry, electron paramagnetic resonance, infrared spectroscopy, potentiometry and elemental analysis. In amperometric titration Mo(VI) with BDTC (pH 4-2) forms a red compound of low solubility. In more acidic media the intensity of coloration is increased and a violet hue develops. On the basis of the data obtained it is concluded that in the amperometric titration of Mo(VI) with potassium BDTC there is first formation of a Mo(VI) compound, which subsequently acquires a red colour as a result of the reduction of Mo(VI) to Mo(V). It was also established that the degree of reduction is small where titration is carried out in the range pH 4.8-0.1. Quantitative determination of Mo is performed most effectively in slightly acidic media. Mo reacts with potassium BDTC in a ratio of 1:2. (E.P.)

  4. Production of 34S-labeled gypsum (Ca34SO4.2H2O Produção de gesso (Ca34SO4.2H2O, marcado com 34S

    Directory of Open Access Journals (Sweden)

    Alexssandra Luiza Rodrigues Molina Rossete

    2006-08-01

    Full Text Available Agricultural gypsum (CaSO4.2H2O stands out as an effective source of calcium and sulfur, and to control aluminum saturation in the soil. Labeled as 34S it can elucidate important aspects of the sulfur cycle. Ca34SO4.2H2O was obtained by chemical reaction between Ca(OH2 and H2(34SO4, performed under slow agitation. The acid was produced by ion exchange chromatography using the Dowex 50WX8 cation exchange resin and a Na2(34SO4 eluting solution. After precipitation, the precipitate was separated and dried in a ventilated oven at 60ºC. From 2.2 L H2SO4 0.2 mol L-1 and 33.6 g Ca(OH2, 73.7 ± 0.6 g Ca34SO4.2H2O were produced on average in the tests, representing a mean yield of 94.6 ± 0.8%, with 98% purity. The 34SO2 gas was obtained from Ca34SO4.2H2O in the presence of NaPO3 in a high vacuum line and was used for the isotopic determination of S in an ATLAS-MAT model CH-4 mass spectrometer.O gesso agrícola (CaSO4.2H2O destaca-se como fonte eficiente de cálcio e enxofre e na redução da saturação de alumínio no solo. O 34S como traçador isotópico pode elucidar aspectos importantes no ciclo do enxofre. Para tanto o Ca34SO4.2H2O foi obtido por reação química entre o Ca(OH2 e solução de H2(34SO4, realizada sob agitação lenta. O ácido foi produzido por cromatografia de troca iônica, utilizando resina catiônica Dowex 50WX8 e solução eluente de Na2(34SO4. Após a precipitação foi separado o precipitado e realizada a secagem em estufa ventilada à temperatura de 60ºC. Nos testes, a partir de 2,2 L de H2SO4 0,2 mol L-1 e 33,6 g de Ca(OH2, foram produzidos em média 73,7 ± 0,6 g de Ca34SO4.2H2O representando um rendimento médio de 94,6 ± 0,8%, com pureza de 98%. A partir do Ca34SO4.2H2O na presença de NaPO3, em linha de alto vácuo, obteve-se o gás 34SO2 utilizado para a determinação isotópica do S no espectrômetro de massas ATLAS-MAT modelo CH-4.

  5. Edge termination of MoS2 and CoMoS catalyst particles

    DEFF Research Database (Denmark)

    Byskov, Line Sjolte; Nørskov, Jens Kehlet; Clausen, B. S.

    2000-01-01

    The edge termination of MoS2 and CoMoS catalyst particles is studied by density functional calculations. We show that for structures without vacancies Mo-terminated edges have the lowest edge energies. Creation of vacancies, which are believed to be active sites in these catalyst systems, leads...

  6. El CO2 como disolvente y como reactivo

    OpenAIRE

    La Franca Pitarresi, Vincenzo Rosario

    2016-01-01

    Existen numerosas ventajas asociada con el uso de CO2 , tanto como disolvente que como reactivo, y todas se pueden resumir en cuatro categorías generales: beneficios ambiental, beneficios de salud y seguridad, beneficios en el procedimiento y beneficios químicos. Los procesos que implican el CO2 como disolvente no aumentaría las emisiones de CO2, más bien proporcionaría una oportunidad para el reciclaje de CO2 residual. Además, los esfuerzos para secuestrar el CO2 producido de los gases de co...

  7. Influence of H2O and H2S on the Composition, Activity, and Stability of Sulfided Mo, CoMo, and NiMo Supported on MgAl2O4 for Hydrodeoxygenation of Ethylene Glycol

    DEFF Research Database (Denmark)

    Dabros, Trine Marie Hartmann; Gaur, Abhijeet; Pintos, Delfina Garcia

    2018-01-01

    In this work, density functional theory (DFT), catalytic activity tests, and in-situ X-ray absorption spectroscopy (XAS) was performed to gain detailed insights into the activity and stability of MoS2, Ni-MoS2, and Co-MoS2 catalysts used for hydrodeoxygenation (HDO) of ethylene glycol upon...

  8. H{sub 2}S and CO{sub 2} filtration of biogas used in internal combustion engines for power generation

    Energy Technology Data Exchange (ETDEWEB)

    Huertas, Jose Ignacio; Izquierdo, Sebastian [Instituto Tecnologico y de Estudios Superiores de Monterrey, (Mexico)]. E-mail: jhuertas@itesm.mx

    2009-09-15

    mass transfer efficiency of the filter when it is compared against the mass transfer expected under quasi equilibrium conditions. Work is under way to design a high efficiency amine column for biogas treatment. [Spanish] En la actualidad, hay un creciente interes en conectar a las redes electricas nacionales miles de pequenas centrales electricas accionadas con fuentes de energia renovables. El uso de biogas como combustible en maquinas de combustion interna conectadas a un generador electrico esta emergiendo como una de las alternativas mas atractivas debido a su muy baja razon de costo beneficio y al muy alto impacto positivo sobre el ambiente. Sin embargo, el uso del biogas para generar electricidad se ha limitado por su alto contenido de H{sub 2}S ({approx}3500 ppm) and CO{sub 2} ({approx}40%). La presencia de CO{sub 2} reduce la densidad energetica del combustible y por lo tanto la salida de potencia del sistema. El alto contenido de H{sub 2}S corroe componentes importantes de la maquina como la camara de combustion, engranes de bronce y el sistema de escape. Este trabajo se orienta al diseno y manufactura de un filtro industrial de bajo costo para esta aplicacion. Entre las diferentes metodologias disponibles, CaO, NaOH y aminas se eligieron como las mas apropiadas para una aplicacion agricola tipica de generadores electricos de 100 kW. Puesto que no hay datos reportados respecto a la capacidad de absorcion de H{sub 2}S de estas sustancia, se propuso medirla mediante un burbujeador. Se trata de un arreglo experimental donde la corriente de gas pasa a traves de una cantidad fija de sustancia absorbente hasta que esta se satura. La capacidad de absorcion se determina como la cantidad de sustancia que se atrapa dividida entre la masa de la sustancia absorbente que se esta usando. Los resultados muestran una capacidad de absorcion de 2.8, 41.4 y 124.8 g de H{sub 2}S por kg de NaOH, CaO y monoetanolamina, respectivamente. Se diseno y fabrico un sistema absorbente de

  9. Self-Driven Photoelectrochemical Splitting of H2S for S and H2 Recovery and Simultaneous Electricity Generation.

    Science.gov (United States)

    Luo, Tao; Bai, Jing; Li, Jinhua; Zeng, Qingyi; Ji, Youzhi; Qiao, Li; Li, Xiaoyan; Zhou, Baoxue

    2017-11-07

    A novel, facile self-driven photoelectrocatalytic (PEC) system was established for highly selective and efficient recovery of H 2 S and simultaneous electricity production. The key ideas were the self-bias function between a WO 3 photoanode and a Si/PVC photocathode due to their mismatched Fermi levels and the special cyclic redox reaction mechanism of I - /I 3 - . Under solar light, the system facilitated the separation of holes in the photoanode and electrons in the photocathode, which then generated electricity. Cyclic redox reactions were produced in the photoanode region as follows: I - was transformed into I 3 - by photoholes or hydroxyl radicals, H 2 S was oxidized to S by I 3 - , and I 3 - was then reduced to I - . Meanwhile, H + was efficiently converted to H 2 in the photocathode region. In the system, H 2 S was uniquely oxidized to sulfur but not to polysulfide (S x n- ) because of the mild oxidation capacity of I 3 - . High recovery rates for S and H 2 were obtained up to ∼1.04 mg h -1 cm -1 and ∼0.75 mL h -1 cm -1 , respectively, suggesting that H 2 S was completely converted into H 2 and S. In addition, the output power density of the system reached ∼0.11 mW cm -2 . The proposed PEC-H 2 S system provides a self-sustaining, energy-saving method for simultaneous H 2 S treatment and energy recovery.

  10. A novel H2S/H2O2 fuel cell operating at the room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sanli, Ayse Elif [Gazi University (Turkey)], email: aecsanli@gmail.com; Aytac, Aylin [Department of Chemistry, Faculty of Science, Gazi University, Teknikokullar (Turkey)], email: aytaca@gazi.edu.tr

    2011-07-01

    This study concerns the oxidation mechanism of hydrogen sulfide and a fuel cell; acidic peroxide is used as the oxidant and basic hydrogen sulfide is the fuel. A solid state H2S/H2O2 stable fuel cell was produced at room temperature. A cell potential of 0.85 V was reached; this is quite remarkable in comparison to the H2S/O2 fuel cell potential of 0.85 V obtained at 850-1000 degree celsius. The hydrogen sulfide goes through an oxidation reaction in the alkaline fuel cell (H2S/H2O2 fuel cell) which opens up the possibility of using the cheaper nickel as a catalyst. As a result, the fuel cell becomes a potentially low cost technology. A further benefit from using H2S as the alkaline liquid H2S/H2O2 fuel cell, is that sulfide ions are oxidized at the anode, releasing electrons. Sulfur produced reacts with the other sulfide ions and forms disulfide and polysulfide ions in basic electrolytes (such as Black Sea water).

  11. Tungsten phosphanylarylthiolato complexes [W{PhP(2-SC6H4)2-kappa3S,S',P} 2] and [W{P(2-SC6H4)3-kappa4S,S',S",P}2]: synthesis, structures and redox chemistry.

    Science.gov (United States)

    Hildebrand, Alexandra; Lönnecke, Peter; Silaghi-Dumitrescu, Luminita; Hey-Hawkins, Evamarie

    2008-09-14

    PhP(2-SHC6H4)2 (PS2H2) reacts with WCl6 with reduction of tungsten to give the air-sensitive tungsten(IV) complex [W{PhP(2-SC6H4)2-kappa(3)S,S',P}2] (1). 1 is oxidised in air to [WO{PhPO(2-SC6H4)2-kappa(3)S,S',O}{PhP(2-SC6H4)2-kappa(3)S,S',P}] (2). The attempted synthesis of 2 by reaction of 1 with iodosobenzene as oxidising agent was unsuccessful. [W{P(2-SC6H4)3-kappa(4)S,S',S",P}2] (3) was formed in the reaction of P(2-SHC6H4)3 (PS3H3) with WCl6. The W(VI) complex 3 contains two PS3(3-) ligands, each coordinated in a tetradentate fashion resulting in a tungsten coordination number of eight. The reaction of 3 with AgBF4 yields the dinuclear tungsten complex [W2{P(2-SC6H4)3-kappa(4)S,S',S",P}3]BF4 (4). Complexes 1-4 were characterised by spectral methods and X-ray structure determination.

  12. A first principle Comparative study of electronic and optical properties of 1H –MoS2 and 2H –MoS2

    International Nuclear Information System (INIS)

    Kumar, Ashok; Ahluwalia, P.K.

    2012-01-01

    First principle calculations of electronic and optical properties of monolayer MoS 2 , so called 1H –MoS 2 , is performed which has emerged as a new direct band gap semiconductor. Before calculations of the properties of 1H –MoS 2 , we have calculated structural parameters, electronic properties (electronic band structure and electronic density of states) and frequency dependent optical response (real and imaginary part of dielectric function, energy loss function, absorption and reflectance spectra) of 2H –MoS 2 and compared with existing experimental results and found that our calculated results are in very good agreements with experimental results. To compare the dielectric functions of bulk (2H –MoS 2 ) and monolayer (1H –MoS 2 ) phases we have further extended these calculations to the single layer MoS 2 (1H –MoS 2 ) which is analogous to graphene. Structural parameters of 1H –MoS 2 are found very close to its bulk 2H –MoS 2 . We find direct electronic band gap at ‘K’ high symmetry point as compared to indirect band gap in its bulk 2H – MoS2. Our calculated dielectric function for 1H – MoS2 shows structure at nearly same energy positions as compared to 2H – MoS2 with additional structure at 3.8 eV. Also additional well defined energy loss peaks revealing the plasmonic resonances at 15.7 eV and 16.0 eV for E vector perpendicular and parallel to c axis respectively for 1H – MoS2 have been found, which are the signatures of surface plasmons at these energies. -- Highlights: ► Structural parameters of 2H-MoS2 and 1H-MoS2 are nearly identical. ► States around the Fermi energy are mainly due to the metal d states. ► Strong hybridization between Mo-d and S-p states below the Fermi energy has been found. ► Optical spectra of 2H-MoS2 finds very good agreements with experimental optical spectra. ► The band gap is found to be direct for 1H-MoS2 as compared to indirect for 2H-MoS2.

  13. A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.

    Science.gov (United States)

    Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu

    2017-08-02

    In order to study the dynamics of the reaction H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), a new potential energy surface (PES) for the ground state of the NaH 2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H 2 (X 1 Σ g + ) and NaH(X 1 Σ + ) obtained on the new NaH 2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH 2 system, the NaH 2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction. Because the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction releases more energy, the product molecules can be excited to a higher vibrational state.

  14. Polysulfides and products of H2S/S-nitrosoglutathione in comparison to H2S, glutathione and antioxidant Trolox are potent scavengers of superoxide anion radical and produce hydroxyl radical by decomposition of H2O2.

    Science.gov (United States)

    Misak, Anton; Grman, Marian; Bacova, Zuzana; Rezuchova, Ingeborg; Hudecova, Sona; Ondriasova, Elena; Krizanova, Olga; Brezova, Vlasta; Chovanec, Miroslav; Ondrias, Karol

    2018-06-01

    Exogenous and endogenously produced sulfide derivatives, such as H 2 S/HS - /S 2- , polysulfides and products of the H 2 S/S-nitrosoglutathione interaction (S/GSNO), affect numerous biological processes in which superoxide anion (O 2 - ) and hydroxyl (OH) radicals play an important role. Their cytoprotective-antioxidant and contrasting pro-oxidant-toxic effects have been reported. Therefore, the aim of our work was to contribute to resolving this apparent inconsistency by studying sulfide derivatives/free radical interactions and their consequent biological effects compared to the antioxidants glutathione (GSH) and Trolox. Using the electron paramagnetic resonance (EPR) spin trapping technique and O 2 - , we found that a polysulfide (Na 2 S 4 ) and S/GSNO were potent scavengers of O 2 - and cPTIO radicals compared to H 2 S (Na 2 S), GSH and Trolox, and S/GSNO scavenged the DEPMPO-OH radical. As detected by the EPR spectra of DEPMPO-OH, the formation of OH in physiological solution by S/GSNO was suggested. All the studied sulfide derivatives, but not Trolox or GSH, had a bell-shaped potency to decompose H 2 O 2 and produced OH in the following order: S/GSNO > Na 2 S 4  ≥ Na 2 S > GSH = Trolox = 0, but they scavenged OH at higher concentrations. In studies of the biological consequences of these sulfide derivatives/H 2 O 2 properties, we found the following: (i) S/GSNO alone and all sulfide derivatives in the presence of H 2 O 2 cleaved plasmid DNA; (ii) S/GSNO interfered with viral replication and consequently decreased the infectivity of viruses; (iii) the sulfide derivatives induced apoptosis in A2780 cells but inhibited apoptosis induced by H 2 O 2 ; and (iv) Na 2 S 4 modulated intracellular calcium in A87MG cells, which depended on the order of Na 2 S 4 /H 2 O 2 application. We suggest that the apparent inconsistency of the cytoprotective-antioxidant and contrasting pro-oxidant-toxic biological effects of sulfide derivatives results from their time

  15. Method for heavy-water production by H2S--H2O chemical exchange process

    International Nuclear Information System (INIS)

    Strathdee, G.G.

    1978-01-01

    The invention discloses a heavy water production stage in a bithermal H 2 S gas H 2 O liquid exchange plant wherein the cold tower is operated under temperature and pressure conditions such that H 2 S in the liquid phase is formed and is maintained in the separation units (sieve trays or plates) of the cold tower. It has been found that the presence of liquid H 2 S acts as an efficient anti-foaming agent

  16. Charge transfer in H2+-H(1s) collisions

    International Nuclear Information System (INIS)

    Errea, L.F.; Macias, A.; Mendez, L.; Rabadan, I.; Riera, A.

    2005-01-01

    We present an ab initio study of H 2 + +H(1s) collisions at H 2 + impact energies between 0.4 and 50keV. Cross sections are obtained within the sudden approximation for rotation and vibration of the diatomic molecule. We have found that anisotropy effects are crucial to correctly describe this system in this energy range

  17. Electron capture, electron loss, and deexcitation of fast H(2 2S) and H(1 2S) atoms in collisions with molecular hydrogen and inert gases

    International Nuclear Information System (INIS)

    Roussel, F.; Pradel, P.; Spiess, G.

    1977-01-01

    Collisions of ground-state (1 2 S) and metastable (2 2 S) hydrogen atoms with rare gases and molecular hydrogen have been studied in the energy range 0.5--3.0 keV. For an acceptance angle of 55 mrad, the electron loss and the electron-capture cross sections of both H(1 2 S) and H(2 2 S) have been measured and compared with previous experimental values. The deexcitation cross section for H(2 2 S) has been deduced with the help of previously measured total-quenching cross sections for H(2 2 S). The ratio of the electron-capture cross sections for H(2 2 S) relative to H(1 2 S) is found to be very large for argon at low energies. The effects of large-angle scattering and of highly excited states of H are discussed

  18. Microwave effects on NiMoS and CoMoS single-sheet catalysts.

    Science.gov (United States)

    Borges, I; Silva, Alexander M; Modesto-Costa, Lucas

    2018-05-04

    Single-sheet nanoclusters of MoS 2 , NiMoS or CoMoS are widely used in hydrodesulfurization (HDS) catalysis in the petroleum industry. In HDS reactions under microwave irradiation, experiments indirectly pointed out that for pristine MoS 2 reaction rates are accelerated because hot spots are generated on the catalyst bed. In this work, we investigated NiMoS and CoMoS isolated single-sheet substituted catalysts before and after thiophene adsorption focusing on quantifying the effect of microwave irradiation. For that purpose, density functional theory (DFT) molecular charge densities of each system were decomposed according to the distributed multipole analysis (DMA) of Stone. Site dipole values of each system were directly associated with a larger or smaller interaction with the microwave field according to a proposed general approach. We showed that microwave enhancement of HDS reaction rates can occur more efficiently in the CoMoS and NiMoS promoted clusters compared to pristine MoS 2 in the following order: CoMoS > NiMoS > MoS 2 . The atomic origin of the catalyst hot spots induced by microwaves was clearly established in the promoted clusters.

  19. Differential cross sections for transfer into the 2S state of hydrogen: H+ + H2, H+ + D2

    International Nuclear Information System (INIS)

    Williams, D.G.; Lee, A.R.; Butcher, E.C.

    1986-01-01

    Differential cross sections for electron capture into the 2S state of hydrogen are presented for the reactions H + + H 2 and H + + D 2 . The results are for laboratory collision energies between 3.3 and 24 keV and scattering angles between 30 and 90'. The measurements expand on the results previously presented. (author)

  20. Investigation of H2S separation from H2S/CH4 mixtures using functionalized and non-functionalized vertically aligned carbon nanotube membranes

    Science.gov (United States)

    Gilani, Neda; Towfighi, Jafar; Rashidi, Alimorad; Mohammadi, Toraj; Omidkhah, Mohammad Reza; Sadeghian, Ahmad

    2013-04-01

    Separation of H2S from binary mixtures of H2S/CH4 using vertically aligned carbon nanotube membranes fabricated in anodic aluminum oxide (AAO) template was studied experimentally. Carbon nanotubes (CNTs) were grown in five AAO templates with different pore diameters using chemical vapor deposition, and CNT/AAO membranes with tubular carbon nanotube structure and open caps were selected for separation of H2S. For this, two tubular CNT/AAO membranes were fabricated with the CNT inner diameters of 23 and 8 nm. It was found that permeability and selectivity of the membrane with inner diameter of 23 nm for CNT were independent of upstream feed pressure and H2S feed concentration unlike that of CNT having an inner diameter of 8 nm. Selectivity of these membranes for separation of H2S was obtained in the ranges of 1.36-1.58 and 2.11-2.86, for CNTs with internal diameters of 23 and 8 nm, respectively. In order to enhance the separation of H2S from H2S/CH4 mixtures, dodecylamine was used to functionalize the CNT/AAO membrane with higher selectivity. The results showed that for amido-functionalized membrane, both upstream feed pressure and H2S partial pressure in the feed significantly increased H2S permeability, and selectivity for H2S being in the range of 3.0-5.57 respectively.

  1. Relative importance of H2 and H2S as energy sources for primary production in geothermal springs.

    Science.gov (United States)

    D'Imperio, Seth; Lehr, Corinne R; Oduro, Harry; Druschel, Greg; Kühl, Michael; McDermott, Timothy R

    2008-09-01

    Geothermal waters contain numerous potential electron donors capable of supporting chemolithotrophy-based primary production. Thermodynamic predictions of energy yields for specific electron donor and acceptor pairs in such systems are available, although direct assessments of these predictions are rare. This study assessed the relative importance of dissolved H(2) and H(2)S as energy sources for the support of chemolithotrophic metabolism in an acidic geothermal spring in Yellowstone National Park. H(2)S and H(2) concentration gradients were observed in the outflow channel, and vertical H(2)S and O(2) gradients were evident within the microbial mat. H(2)S levels and microbial consumption rates were approximately three orders of magnitude greater than those of H(2). Hydrogenobaculum-like organisms dominated the bacterial component of the microbial community, and isolates representing three distinct 16S rRNA gene phylotypes (phylotype = 100% identity) were isolated and characterized. Within a phylotype, O(2) requirements varied, as did energy source utilization: some isolates could grow only with H(2)S, some only with H(2), while others could utilize either as an energy source. These metabolic phenotypes were consistent with in situ geochemical conditions measured using aqueous chemical analysis and in-field measurements made by using gas chromatography and microelectrodes. Pure-culture experiments with an isolate that could utilize H(2)S and H(2) and that represented the dominant phylotype (70% of the PCR clones) showed that H(2)S and H(2) were used simultaneously, without evidence of induction or catabolite repression, and at relative rate differences comparable to those measured in ex situ field assays. Under in situ-relevant concentrations, growth of this isolate with H(2)S was better than that with H(2). The major conclusions drawn from this study are that phylogeny may not necessarily be reliable for predicting physiology and that H(2)S can dominate over H(2

  2. Large-area MoS2 grown using H2S as the sulphur source

    International Nuclear Information System (INIS)

    Dumcenco, Dumitru; Ovchinnikov, Dmitry; Lopez Sanchez, Oriol; Kis, Andras; Gillet, Philippe; Alexander, Duncan T L; Lazar, Sorin; Radenovic, Aleksandra

    2015-01-01

    We report on the growth of molybdenum disulphide (MoS 2 ) using H 2 S as a gas-phase sulfur precursor that allows controlling the domain growth direction of domains in both vertical (perpendicular to the substrate plane) and horizontal (within the substrate plane), depending on the H 2 S:H 2 ratio in the reaction gas mixture and temperature at which they are introduced during growth. Optical and atomic force microscopy measurements on horizontal MoS 2 demonstrate the formation of monolayer triangular-shape domains that merge into a continuous film. Scanning transmission electron microscopy of monolayer MoS 2 shows a regular atomic structure with a hexagonal symmetry. Raman and photoluminescence spectra confirm the monolayer thickness of the material. Field-effect transistors fabricated on MoS 2 domains that are transferred onto Si/SiO 2 substrates show a mobility similar to previously reported exfoliated and chemical vapor deposition-grown materials. (paper)

  3. Hydrogen Dynamics in Cyanobacteria Dominated Microbial Mats Measured by Novel Combined H2/H2S and H2/O2 Microsensors

    Directory of Open Access Journals (Sweden)

    Karen Maegaard

    2017-10-01

    Full Text Available Hydrogen may accumulate to micromolar concentrations in cyanobacterial mat communities from various environments, but the governing factors for this accumulation are poorly described. We used newly developed sensors allowing for simultaneous measurement of H2S and H2 or O2 and H2 within the same point to elucidate the interactions between oxygen, sulfate reducing bacteria, and H2 producing microbes. After onset of darkness and subsequent change from oxic to anoxic conditions within the uppermost ∼1 mm of the mat, H2 accumulated to concentrations of up to 40 μmol L-1 in the formerly oxic layer, but with high variability among sites and sampling dates. The immediate onset of H2 production after darkening points to fermentation as the main H2 producing process in this mat. The measured profiles indicate that a gradual disappearance of the H2 peak was mainly due to the activity of sulfate reducing bacteria that invaded the formerly oxic surface layer from below, or persisted in an inactive state in the oxic mat during illumination. The absence of significant H2 consumption in the formerly oxic mat during the first ∼30 min after onset of anoxic conditions indicated absence of active sulfate reducers in this layer during the oxic period. Addition of the methanogenesis inhibitor BES led to increase in H2, indicating that methanogens contributed to the consumption of H2. Both H2 formation and consumption seemed unaffected by the presence/absence of H2S.

  4. A role for H2S in the microcirculation of newborns: the major metabolite of H2S (thiosulphate is increased in preterm infants.

    Directory of Open Access Journals (Sweden)

    Rebecca M Dyson

    Full Text Available Excessive vasodilatation during the perinatal period is associated with cardiorespiratory instability in preterm neonates. Little evidence of the mechanisms controlling microvascular tone during circulatory transition exists. We hypothesised that hydrogen sulphide (H2S, an important regulator of microvascular reactivity and central cardiac function in adults and animal models, may contribute to the vasodilatation observed in preterm newborns. Term and preterm neonates (24-43 weeks gestational age were studied. Peripheral microvascular blood flow was assessed by laser Doppler. Thiosulphate, a urinary metabolite of H2S, was determined by high performance liquid chromatography as a measure of 24 hr total body H2S turnover for the first 3 days of postnatal life. H2S turnover was greatest in very preterm infants and decreased with increasing gestational age (p = 0.0001. H2S turnover was stable across the first 72 hrs of life in older neonates. In very preterm neonates, H2S turnover increased significantly from day 1 to 3 (p =0.0001; and males had higher H2S turnover than females (p = 0.04. A significant relationship between microvascular blood flow and H2S turnover was observed on day 2 of postnatal life (p = 0.0004. H2S may play a role in maintaining microvascular tone in the perinatal period. Neonates at the greatest risk of microvascular dysfunction characterised by inappropriate peripheral vasodilatation--very preterm male neonates--are also the neonates with highest levels of total body H2S turnover suggesting that overproduction of this gasotransmitter may contribute to microvascular dysfunction in preterms. Potentially, H2S is a target to selectively control microvascular tone in the circulation of newborns.

  5. Evaluation of plasma H2S levels and H2S synthesis in streptozotocin induced Type-2 diabetes-an experimental study based on Swietenia macrophylla seeds

    Directory of Open Access Journals (Sweden)

    Moumita Dutta

    2014-05-01

    Conclusions: Although considering a small sample size, it can conclude that the fasting blood glucose levels are inversely related to plasma H2S levels as well as H2S synthesis activity in plasma and the extract of S. macrophylla is associated with increased plasma H2S levels with effective lowering of blood glucose in streptozotocin induced diabetic rats.

  6. Obtención de silicatos de calcio empleando como precursores residuos sólidos. Influencia del mezclado de reactivos en fase seca o fase húmeda

    Directory of Open Access Journals (Sweden)

    Corpas Iglesias, F. A.

    2011-02-01

    Full Text Available The suitability of re-using residues marble, remaining from cutting marble, as a source of calcium-oxide, as well as the resultant ashes from the combustion of the wastes generated in the process of manufacturing boards from derivates of wood, as a source of silica, as raw material for the production of calcium silicate products has been determined. First of all, the influence of water has been studied in the initial phase of mixing residues. Marble and ashes have been mixed in molar relation CaO:SiO2 of 1:1 using two different ways: using a planetary ball mill (while in solid state or agitating at 90 ºC (2 h using a 60 wt% of water (while in humid state. Later, both mixtures were sintered at 1100 ºC (24 h. In order to use the obtained calcium-silicates as ceramic insulating thermal materials, the samples were compressed at 15 Tm obtaining bricks from which the technological properties have been studied. The ceramic materials obtained from mixing the residues in dry phase, as well as those obtained in the wet phase, can be used as thermal insulators, showing values of conductivity of 0.18 and 0.12 w/m2K, with an elevated resistance to compressive strength.

    Se ha determinado la posibilidad de reutilizar los residuos procedentes del corte de mármol, como fuente de óxido de calcio, y las cenizas resultantes de la combustión de los residuos generados en el proceso de fabricación de tableros de derivados de madera, como fuente de sílice. A partir de ambas materias primas, se obtienen silicatos de calcio. Se ha estudiado la influencia de agua en la fase inicial de mezclado de los residuos. Para ello mármol y cenizas se han mezclado en relación molar CaO:SiO2 1:1, en una primera ruta, en fase seca, empleando un molino de bolas, o en una segunda ruta, en fase húmeda, mediante agitación a 90 ºC (2 h empleando un 60 % en peso de agua. Posteriormente, ambas mezclas se sinterizan a 1100 ºC (24 h. Con

  7. Functionalization of liquid-exfoliated two-dimensional 2H-MoS2.

    Science.gov (United States)

    Backes, Claudia; Berner, Nina C; Chen, Xin; Lafargue, Paul; LaPlace, Pierre; Freeley, Mark; Duesberg, Georg S; Coleman, Jonathan N; McDonald, Aidan R

    2015-02-23

    Layered two-dimensional (2D) inorganic transition-metal dichalchogenides (TMDs) have attracted great interest as a result of their potential application in optoelectronics, catalysis, and medicine. However, methods to functionalize and process such 2D TMDs remain scarce. We have established a facile route towards functionalized layered MoS2 . We found that the reaction of liquid-exfoliated 2D MoS2 , with M(OAc)2 salts (M=Ni, Cu, Zn; OAc=acetate) yielded functionalized MoS2 -M(OAc)2 materials. Importantly, this method furnished the 2H-polytype of MoS2 which is a semiconductor. X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT-IR), and thermogravimetric analysis (TGA) provide strong evidence for the coordination of MoS2 surface sulfur atoms to the M(OAc)2 salt. Interestingly, functionalization of 2H-MoS2 allows for its dispersion/processing in more conventional laboratory solvents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Chemical absorption of H2S for biogas purification

    Directory of Open Access Journals (Sweden)

    Horikawa M.S.

    2004-01-01

    Full Text Available This work presents an experimental study of purification of a biogas by removal of its hydrogen sulphide (H2S content. The H2S was removed by means of chemical absorption in an iron-chelated solution catalyzed by Fe/EDTA, which converts H2S into elemental sulphur (S. Preparation of the catalyst solution and the results of biogas component absorption in the catalyst solution (0.2 mol/L are presented. These results are compared with those for physical absorption into pure water under similar conditions. Experimental results demonstrate that, under the same experimental conditions, a higher percentage of H2S can be removed in the catalytic solution than in water. In a continuous counter current using adequate flow-rate phases contact at room temperature and low gas pressure, the results demonstrate that is possible to totally remove the H2S from the biogas with the prepared catalytic solution.

  9. H2S and polysulfide metabolism: Conventional and unconventional pathways.

    Science.gov (United States)

    Olson, Kenneth R

    2018-03-01

    It is now well established that hydrogen sulfide (H 2 S) is an effector of a wide variety of physiological processes. It is also clear that many of the effects of H 2 S are mediated through reactions with cysteine sulfur on regulatory proteins and most of these are not mediated directly by H 2 S but require prior oxidation of H 2 S and the formation of per- and polysulfides (H 2 S n , n = 2-8). Attendant with understanding the regulatory functions of H 2 S and H 2 S n is an appreciation of the mechanisms that control, i.e., both increase and decrease, their production and catabolism. Although a number of standard "conventional" pathways have been described and well characterized, novel "unconventional" pathways are continuously being identified. This review summarizes our current knowledge of both the conventional and unconventional. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. The solubility of gold in H 2 O-H 2 S vapour at elevated temperature and pressure

    Science.gov (United States)

    Zezin, Denis Yu.; Migdisov, Artashes A.; Williams-Jones, Anthony E.

    2011-09-01

    This experimental study sheds light on the complexation of gold in reduced sulphur-bearing vapour, specifically, in H 2O-H 2S gas mixtures. The solubility of gold was determined in experiments at temperatures of 300, 350 and 365 °C and reached 2.2, 6.6 and 6.3 μg/kg, respectively. The density of the vapour varied from 0.02 to 0.22 g/cm 3, the mole fraction of H 2S varied from 0.03 to 0.96, and the pressure in the cell reached 263 bar. Statistically significant correlations of the amount of gold dissolved in the fluid with the fugacity of H 2O and H 2S permit the experimental data to be fitted to a solvation/hydration model. According to this model, the solubility of gold in H 2O-H 2S gas mixtures is controlled by the formation of sulphide or bisulphide species solvated by H 2S or H 2O molecules. Formation of gold sulphide species is favoured statistically over gold bisulphide species and thus the gold is interpreted to dissolve according to reactions of the form: Au(s)+(n+1)HS(g)=AuS·(HS)n(g)+H(g) Au(s)+HS(g)+mHO(g)=AuS·(HO)m(g)+H(g) Equilibrium constants for Reaction (A1) and the corresponding solvation numbers ( K A1 and n) were evaluated from the study of Zezin et al. (2007). The equilibrium constants as well as the hydration numbers for Reaction (A2) ( K A2 and m) were adjusted simultaneously by a custom-designed optimization algorithm and were tested statistically. The resulting values of log K A2 and m are -15.3 and 2.3 at 300 and 350 °C and -15.1 and 2.2 at 365 °C, respectively. Using the calculated stoichiometry and stability of Reactions (A1) and (A2), it is now possible to quantitatively evaluate the contribution of reduced sulphur species to the transport of gold in aqueous vapour at temperatures up to 365 °C. This information will find application in modelling gold ore-forming processes in vapour-bearing magmatic hydrothermal systems, notably those of epithermal environments.

  11. Endogenous mitigation of H2S inside of the landfills.

    Science.gov (United States)

    Fang, Yuan; Zhong, Zhong; Shen, Dongsheng; Du, Yao; Xu, Jing; Long, Yuyang

    2016-02-01

    Vast quantities of hydrogen sulfide (H2S) emitted from landfill sites require urgent disposal. The current study focused on source control and examined the migration and conversion behavior of sulfur compounds in two lab-scale simulated landfills with different operation modes. It aimed to explore the possible strategies and mechanisms for H2S endogenous mitigation inside of landfills during decomposition. It was found that the strength of H2S emissions from the landfill sites was dependent on the municipal solid waste (MSW) degradation speed and vertical distribution of sulfide. Leachate recirculation can shorten both the H2S influence period and pollution risk to the surrounding environment. H2S endogenous mitigation may be achieved by chemical oxidation, biological oxidation, adsorption, and/or precipitation in different stages. Migration and conversion mainly affected H2S release behavior during the initial stabilization phase in the landfill. Microbial activities related to sulfur, nitrogen, and iron can further promote H2S endogenous mitigation during the high reducing phase. Thus, H2S endogenous mitigation can be effectively enhanced via control of the aforementioned processes.

  12. Emission of Lyman α radiation in H2 + H*(2s) collisions at thermal energies

    International Nuclear Information System (INIS)

    Stern, B.

    1991-01-01

    A previously-published study of the thermal-energy collision between H 2 and metastable H*(2s), which could lead to the emission of Lyman α radiation, is reconsidered to take into account possible polarization effects. The total was function of the system is expanded in terms of the molecular states of the intermediate complex H 2 * , which constitute the minimal basis of the four adiabatic states dissociating into H 2 + H*(n=2) where they are normally degenerate in energy. The results of the calculation show the existence, between three of those states, of average values of the separation distance R (R ≅ 10 atomic units) of long range (ΔR ≅ 2 au) electronic interactions which depend on the geometric form of the H 2 * molecule. From the molecular data the hypothesis of no longer considering H 2 with H*(2s) as a rigid rotator is postulated and justified, after a purely quantum mechanical treatment of the radial equations. The mean ratio of the (oscillating) polarization angular differential cross sections tot he elastic ones is found important (> ∼ 1/10). The inelastic phenomena are anticipated to be more marked in the ortho than in the para hydrogen at a low collision energy (75 meV). (15 refs., 2 tabs., 9 figs.)

  13. H2S-induced S-sulfhydration of pyruvate carboxylase contributes to gluconeogenesis in liver cells.

    Science.gov (United States)

    Ju, YoungJun; Untereiner, Ashley; Wu, Lingyun; Yang, Guangdong

    2015-11-01

    Cystathionine gamma-lyase (CSE)-derived hydrogen sulfide (H(2)S) possesses diverse roles in the liver, affecting lipoprotein synthesis, insulin sensitivity, and mitochondrial biogenesis. H(2)S S-sulfhydration is now proposed as a major mechanism for H(2)S-mediated signaling. Pyruvate carboxylase (PC) is an important enzyme for gluconeogenesis. S-sulfhydration regulation of PC by H(2)S and its implication in gluconeogenesis in the liver have been unknown. Gene expressions were analyzed by real-time PCR and western blotting, and protein S-sulfhydration was assessed by both modified biotin switch assay and tag switch assay. Glucose production and PC activity was measured with coupled enzyme assays, respectively. Exogenously applied H(2)S stimulates PC activity and gluconeogenesis in both HepG2 cells and mouse primary liver cells. CSE overexpression enhanced but CSE knockout reduced PC activity and gluconeogenesis in liver cells, and blockage of PC activity abolished H(2)S-induced gluconeogenesis. H(2)S had no effect on the expressions of PC mRNA and protein, while H(2)S S-sulfhydrated PC in a dithiothreitol-sensitive way. PC S-sulfhydration was significantly strengthened by CSE overexpression but attenuated by CSE knockout, suggesting that H(2)S enhances glucose production through S-sulfhydrating PC. Mutation of cysteine 265 in human PC diminished H(2)S-induced PC S-sulfhydration and activity. In addition, high-fat diet feeding of mice decreased both CSE expression and PC S-sulfhydration in the liver, while glucose deprivation of HepG2 cells stimulated CSE expression. CSE/H(2)S pathway plays an important role in the regulation of glucose production through S-sulfhydrating PC in the liver. Tissue-specific regulation of CSE/H(2)S pathway might be a promising therapeutic target of diabetes and other metabolic syndromes. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Plasmas pour la destruction de l'H2S et des mercaptans Plasmas for Destruction of H2s and Mercaptans

    Directory of Open Access Journals (Sweden)

    Czernichowski A.

    2006-12-01

    Full Text Available Cet article passe en revue l'utilisation des plasmas comme milieu activateurs d'une oxydation de H2S ou CH3SH dilués dans l'air, le CO2 ou la vapeur d'eau, à fins de conversion en SO, moins malodorant. Le produit peut être ensuite utilisé comme réactif dans un processus similaire à celui de Claus, en présence d'eau, ce qui permet de convertir deux fois plus de polluants initiaux en soufre élémentaire. Une attention particulière est portée aux décharges électriques glissantes (GlidArc. Ces décharges puissantes produisent un plasma non thermique qui active des réactions oxydatrices. La plupart des expériences ont été réalisées en utilisant les réacteurs GlidArc-I à un ou à quatre étages. Les sulfures dilués dans l'air dans des concentrations initiales atteignant jusqu'à 1 %( H2S ou 0,1 % (CH3SH ont été traités sous des flux jusqu'à 70 m3(n/h d'air pollué et sous une puissance de 5 kW. Les essais ont été réalisés sous 1 atm. Une dépollution jusqu'à 100 % a été obtenue moyennant un coût énergétique assez bas dépendant de la concentration initiale du polluant : environ 1000 kWh par kilogramme de soufre extrait pour 100 ppm de H2S et seulement 10 kWh/kg pour 1 % initial d'H2S dans l'air. Pratiquement les mêmes coûts ont été observés dans le cas de mélanges CH3SH-air. En utilisant une très simple douche en recirculation d'eau qui lave les gaz sortants (l'eau se sature avec le SO2 et capture ainsi l'H2S non traité nous avons divisé ces coûts d'énergie par trois, en évitant également l'émission de SO2, et en obtenant du soufre non toxique. Un nouveau principe (et réacteur GlidArc-II est ensuite présenté ; il s'agit d'une brosseà décharges électriques. Nos premiers tests sont très prometteurs car dès à présent, nous divisons déjà la dépense énergétique par deux par rapport au GlidArc-I. L'échelle industrielle peut par conséquent être envisagée. Plasmas are reviewed as activation

  15. A new global analytical potential energy surface of NaH2+ system and dynamical calculation for H(2S) + NaH+(X2Σ+) → Na+(1S) + H2(X1Σg+) reaction

    Science.gov (United States)

    Yuan, Meiling; Li, Wentao; Yuan, Jiuchuang

    2018-05-01

    A new global potential energy surface (PES) of the NaH2+ system is constructed by fitting 27,621 ab initio energy points with the neural network method. The root mean square error of the new PES is only 4.1609 × 10-4 eV. Based on the new PES, dynamical calculations have been performed using the time-dependent quantum wave packet method. These results are then compared with the H(2S) + LiH+(X2Σ+) → Li+(1S) + H2(X1Σg+) reaction. The direct abstract mechanism is found to play an important role in the reaction because only forward scattering signals on the differential cross section results for all calculated collision energies.

  16. Degradation kinetics of monoethanolamine during CO2 and H2 S absorption from biogas

    Directory of Open Access Journals (Sweden)

    Preecha Kasikamphaiboon

    2015-02-01

    Full Text Available The rate of degradation of MEA during CO2 and H2 S absorption in the biogas upgrading process was examined in four degradation systems, i.e., MEA-CO2 , MEA-CO2 -O2 , MEA-CO2 -H2 S and MEA-CO2 -O2 -H2 S. Degradation experiments were performed in a 800-ml stainless steel autoclave reactor, using MEA concentrations of 3 and 5 mol/L, CO2 loadings of 0.4 and 0.5 mol CO2 /mol MEA, O2 pressure of 200 kPa, and H2 S concentrations of 84 and 87 mg/L at temperatures of 120 and 140C. The results showed that, for the MEA-CO2 system, an increase in temperature or MEA concentration resulted in a higher rate of MEA degradation. In contrast, an increase in CO2 loading in the MEA-CO2 -O2 system led to a reduction of MEA degradation. The degradation rate of the system with O2 was with 8.3 times as high as that of the system without O2 . The presence of H2 S did not appear to affect the rate of degradation in the MEA-CO2 -H2 S system. However, for the system in which both H2 S and O2 were present, the MEA degradation was additionally induced by H2 S, thus, resulting in higher degradation rates than those of the system with O2 only. The extent of degradation under the same period of time increased in the order MEA-CO2 , MEA-CO2 -H2 S < MEA-CO2 -O2 < MEA-CO2 -O2 -H2 S.

  17. [3H]-labelling of hydroxyethyl groups - synthesis of S-(2-hydroxy [2-3H] ethyl) glutathione and of [3H]-melphalan

    International Nuclear Information System (INIS)

    Verny, M.; Nicolas, C.

    1988-01-01

    The easy preparation of 2-bromo [1- 3 H] ethanol allows the tritium labelling of molecules bearing S- or N-hydroxyethyl groups. Thus S-(2-hydroxy [2- 3 H] ethyl) glutathione and [ 3 H]-Melphalan were synthesised with specific radioactivities of around 10 mCi/mmol (370 MBq/mmol). These values could be theoretically raised to 10 Ci/mmol (370 GBq/mmol), according to the specific activity of the labelling precursor, sodium [ 3 H] borohydride. (author)

  18. Raman spectrum of predissociating H/sub 2/S

    International Nuclear Information System (INIS)

    Kleinermanns, K.; Suntz, R.; Schneider, R.

    1986-01-01

    Emission spectroscopy of photodissociating molecules provides interesting insights into the short-time dynamics of bond raptures. The authors report here a resolved H/sub 2/S photoemission spectrum after excitation at 193 nm, although its electronic spectrum in this wavelength region is diffuse. The electronic spectrum of H/sub 2/S between 250 and 170 nm is nearly continuous probably due to predissociation

  19. SOFT X-RAY IRRADIATION OF H{sub 2}S ICE AND THE PRESENCE OF S{sub 2} IN COMETS

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Escobar, A.; Munoz Caro, G. M. [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Ciaravella, A.; Candia, R.; Micela, G. [INAF-Osservatorio Astronomico di Palermo, P.za Parlamento 1, 90134 Palermo (Italy); Cecchi-Pestellini, C., E-mail: munozcg@cab.inta-csic.es [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, I-09012 Capoterra (Canada) (Italy)

    2012-06-01

    Little is known about the effects of X-rays in interstellar ices. To understand the sulfur depletion in dense clouds and the presence of S{sub 2} in comets, we simulated experimentally the soft X-ray processing (0.3 keV) of H{sub 2}S ice for the first time. Experiments were performed under ultrahigh vacuum conditions at 8 K using infrared and quadrupole mass spectrometry to monitor the solid and gas phases, respectively. A UV irradiation experiment using a similar dose was made for comparison. After X-ray irradiation, an infrared absorption appears near 4.0 {mu}m which is attributed to H{sub 2}S{sub 2} formation in the ice. This identification is also supported by the desorption at 133 K of m/z 66, 65, 64, corresponding to the mass fragments of H{sub 2}S{sub 2}. The H{sub 2}S{sub 2} species is expected to be present in interstellar and cometary ices that were processed by X-rays. Further irradiation leads to dissociation of this molecule forming S{sub 2} and larger S-molecules up to S{sub 8}, which may explain the depletion of sulfur in dense clouds. CS{sub 2} was so far the parent molecule proposed for S{sub 2} formation in comets. But the abundance of H{sub 2}S{sub 2}, formed by irradiation of pure H{sub 2}S or H{sub 2}S in an H{sub 2}O-ice matrix, should be larger than that of CS{sub 2} in the ice, the latter requiring a carbon source for its formation. Based on our experimental results, we propose that S{sub 2} in comets could be formed by dissociation of H{sub 2}S{sub 2} in the ice.

  20. High-Temperature Corrosion of T92 Steel in N{sub 2}/H{sub 2}O/H{sub 2}S-Mixed Gas

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yuke; Kim, Min Jung; Park, Soon Yong; Abro, M. Ali; Yadav, Poonam; Lee, Dong Bok [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-06-15

    The ASTM T92 steel was corroded at 600 ℃ and 800 ℃ at 1 atm of N{sub 2}/3.1%H{sub 2}O/2.42%H{sub 2}S-mixed gas. The formed scales were thick and fragile. They consisted primarily of the outer FeS scale and the inner (FeS, FeCr{sub 2}S{sub 4})-mixed scale containing a small amount of the Cr{sub 2}O{sub 3} scale. This indicated that corrosion occurred mainly via sulfidation rather than oxidation due to the H{sub 2}S gas. Since FeS was present throughout the whole scale, T92 steel was non-protective, displaying high corrosion rates.

  1. Emission of hydrogen sulfide (H2S) at a waterfall in a sewer: study of main factors affecting H2S emission and modeling approaches.

    Science.gov (United States)

    Jung, Daniel; Hatrait, Laetitia; Gouello, Julien; Ponthieux, Arnaud; Parez, Vincent; Renner, Christophe

    2017-11-01

    Hydrogen sulfide (H 2 S) represents one of the main odorant gases emitted from sewer networks. A mathematical model can be a fast and low-cost tool for estimating its emission. This study investigates two approaches to modeling H 2 S gas transfer at a waterfall in a discharge manhole. The first approach is based on an adaptation of oxygen models for H 2 S emission at a waterfall and the second consists of a new model. An experimental set-up and a statistical data analysis allowed the main factors affecting H 2 S emission to be studied. A new model of the emission kinetics was developed using linear regression and taking into account H 2 S liquid concentration, waterfall height and fluid velocity at the outlet pipe of a rising main. Its prediction interval was estimated by the residual standard deviation (15.6%) up to a rate of 2.3 g H 2h -1 . Finally, data coming from four sampling campaigns on sewer networks were used to perform simulations and compare predictions of all developed models.

  2. Calculations of H+ + Cs→H(2s or 2p) + Cs+ reaction cross sections

    International Nuclear Information System (INIS)

    Valance, A.; Spiess, G.

    1975-01-01

    The H(2s) and H(2p) atom production cross-sections are calculated and compared with experimental results in the incident proton energy range 250-2400eV. The calculation method used involves a perturbation of the stationary molecular states, these adiabatic potentials being obtained from a pseudo-potential describing the core of cesium [fr

  3. Electron capture from H(2s) by H+ at low energies

    International Nuclear Information System (INIS)

    Blanco, S.A.; Falcon, C.A.; Piacentini, R.D.

    1986-01-01

    Total cross sections for resonant electron capture by protons from metastable H(2s) targets have been computed in a six-state molecular close-coupling formalism. Transitions between degenerate sublevels of the L shell of the target occurring at large internuclear distances have been taken into account in the impact parameter approximation. Cross sections are presented for impact velocities between 0.05 and 0.3 au. The results are compared with theoretical calculations for capture from H(2s) by Li 3+ , C 6+ and N 7+ . (author)

  4. Computational study on the mechanisms and energetics of trimethylindium reactions with H2O and H2S.

    Science.gov (United States)

    Raghunath, P; Lin, M C

    2007-07-19

    The reactions of trimethylindium (TMIn) with H2O and H2S are relevant to the chemical vapor deposition of indium oxide and indium sulfide thin films. The mechanisms and energetics of these reactions in the gas phase have been investigated by density functional theory and ab initio calculations using the CCSD(T)/[6-31G(d,p)+Lanl2dz]//B3LYP/[6-31G(d,p)+Lanl2dz] and CCSD(T)/[6-31G(d,p)+Lanl2dz] //MP2/[6-31G(d,p)+Lanl2dz] methods. The results of both methods are in good agreement for the optimized geometries and relative energies. When TMIn reacts with H2O and H2S, initial molecular complexes [(CH3)3In:OH2 (R1)] and [(CH3)3In:SH2 (R2)] are formed with 12.6 and 3.9 kcal/mol binding energies. Elimination of a CH4 molecule from each complex occurs with a similar energy barrier at TS1 (19.9 kcal/mol) and at TS3 (22.1 kcal/mol), respectively, giving stable intermediates (CH3)2InOH and (CH3)2InSH. The elimination of the second CH4 molecule from these intermediate products, however, has to overcome very high and much different barriers of 66.1 and 53.2 kcal/mol, respectively. In the case of DMIn with H2O and H2S reactions, formation of both InO and InS is exothermic by 3.1 and 30.8 kcal/mol respectively. On the basis of the predicted heats of formation of R1 and R2 at 0 K and -20.1 and 43.6 kcal/mol, the heats of formation of (CH3)2InOH, (CH3)2InSH, CH3InO, CH3InS, InO, and InS are estimated to be -20.6, 31.8, and 29.0 and 48.4, 35.5, and 58.5 kcal/mol, respectively. The values for InO and InS are in good agreement with available experimental data. A similar study on the reactions of (CH3)2In with H2O and H2S has been carried out; in these reactions CH3InOH and CH3InSH were found to be the key intermediate products.

  5. Synthesis and characterization of MoS{sub 2} cocatalysts for H{sub 2}-generation; Darstellung und Charakterisierung von MoS{sub 2} Cokatalysatoren fuer die H{sub 2}-Entwicklung

    Energy Technology Data Exchange (ETDEWEB)

    Djamil, John

    2015-10-05

    As a suitable alternative to fossil fuels and nuclear energy light induced generation of H{sub 2} represents a trend-setting research area in the field of regenerative energy. Therefore photocatalysts, which provide surface sites for light driven reduction of protons to H{sub 2}, are being investigated and developed. Enhancement of photocatalytic systems can be achieved by the usage of cocatalysts, which simplify charge separation and provide additional catalytic active sites as well. In the present work cocatalysts based on MoS{sub 2} were synthesized, characterized and investigated for photocatalytic H{sub 2} generation. MoS{sub 2} cocatalysts were synthesized by thermal decomposition of tetraalkyl ammonium thiomolybdates with varying carbon content in the organic cation and by mechanical treatment of bulk MoS{sub 2} respectively. Hence, samples with differing chemical composition as well as structural properties were obtained. Based on these findings relations between chemical composition, microstructural properties and photocatalytic activity were supposed to reveal. Nanoparticulate molybdenum sulfides resulted in both synthetic routes. Thermal decomposition of tetraalkyl ammonium thiomolybdates yielded in carbon containing molybdenum sulfide nanocomposites, in which carbon and sulfur content and the crystallite size as well varied with the carbon amount in the precursor. Additionally a composite with a significant enlarged interlayer distance between the MoS{sub 2} layers was obtained by thermal decomposition of (Ph{sub 4}P){sub 2}MoS{sub 4}. Such interlayer expansion could be explained by an insertion of in situ generated Ph{sub 3}PS- and (Ph{sub 4}P){sub 2}S-molecules between the MoS{sub 2} layers. While Ph{sub 3}PS-molecules were bonded through Mo-S-bonds to the MoS{sub 2} layers, (Ph{sub 4}P){sub 2}S-molecules remained free in rotation between MoS{sub 2} sheets. The mechanical treatment of bulk MoS{sub 2} resulted in different-sized MoS{sub 2

  6. H2S: a universal defense against antibiotics in bacteria.

    Science.gov (United States)

    Shatalin, Konstantin; Shatalina, Elena; Mironov, Alexander; Nudler, Evgeny

    2011-11-18

    Many prokaryotic species generate hydrogen sulfide (H(2)S) in their natural environments. However, the biochemistry and physiological role of this gas in nonsulfur bacteria remain largely unknown. Here we demonstrate that inactivation of putative cystathionine β-synthase, cystathionine γ-lyase, or 3-mercaptopyruvate sulfurtransferase in Bacillus anthracis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli suppresses H(2)S production, rendering these pathogens highly sensitive to a multitude of antibiotics. Exogenous H(2)S suppresses this effect. Moreover, in bacteria that normally produce H(2)S and nitric oxide, these two gases act synergistically to sustain growth. The mechanism of gas-mediated antibiotic resistance relies on mitigation of oxidative stress imposed by antibiotics.

  7. H2S-mediated thermal and photochemical methane activation.

    Science.gov (United States)

    Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric V

    2013-12-02

    Sustainable, low-temperature methods for natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) mixed with methane, deemed altogether as sub-quality or "sour" gas. We propose a unique method of activation to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3 , and an energy carrier such as H2. For this purpose, we investigated the H2S-mediated methane activation to form a reactive CH3SH species by means of direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4 + H2S complex resulted in a barrierless relaxation by a conical intersection to form a ground-state CH3SH + H2 complex. The resulting CH3SH could further be coupled over acidic catalysts to form higher hydrocarbons, and the resulting H2 used as a fuel. This process is very different from conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced control over the conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the current industrial steam methane reforming (SMR). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Synthesis and spectroscopic stereospecificity assay of the deuterated quinolizidine alkaloids (2S)-[2H]- and (2R)-[2H]-sparteine

    International Nuclear Information System (INIS)

    Ebner, T.; Meese, C.O.; Rebell, J.

    1989-01-01

    Borohydride reduction of the (+)-1,2-dehydrosparteinium salts proceeds almost exclusively from the Si side, yielding, respectively, the stereoselectively (2S)(β)-deuterated (-)-sparteine and the (2R)(α)-deuterated (-)-sparteine. Stereo-chemistry and isotopic purity of the deuterium label (≥98%) are established unequivocally by 1 H, 2 H and 13 C NMR spectroscopy. (author)

  9. Catalytic activity of Cu4-cluster to adsorb H2S gas: h-BN nanosheet

    Science.gov (United States)

    Kansara, Shivam; Gupta, Sanjeev K.; Sonvane, Yogesh

    2018-05-01

    We have investigated the electronic properties, adsorptions strength and charge transfer using first principles calculations using density functional theory (DFT). The hexagonal boron nitride (h-BN) substrate shows metallic behavior, which helps to enhance the absorption process. The adsorption of three different orientations (S, D and T) of the H2S gas molecules to analyze the maximum adsorption strength from them onto a copper cluster (Cu4) based on h-BN nanosheet. The maximum adsorption energy of the H2S gas molecule is -1.50 eV for the S orientation and for D and U, it is -0.71 eV and -0.78 eV, respectively. The results show that Cu4 cluster helps to capture H2S gas from the environment and results are useful for the cleaning environment from the toxic gases.

  10. Spectroscopy, microscopy and theoretical study of NO adsorption on MoS2 and Co-Mo-S hydrotreating catalysts

    DEFF Research Database (Denmark)

    Topsøe, Nan-Yu; Tuxen, Anders Kyrme; Hinnemann, Berit

    2011-01-01

    nfrared (IR) spectroscopy using NO as a probe molecule has been one of the important methods for characterizing hydrotreating catalysts, since this technique provides information on the nature and quantity of active edge sites of these catalysts. However, due to the strong adsorption of NO, which......) calculations, we present new atomic-scale insight into the nature of NO adsorption on MoS2 and Co-Mo-S nanoclusters. The DFT calculations and STM experiments show that NO does not adsorb at fully sulfided MoS2 edges not containing hydrogen. However, typical sulfided catalysts will have hydrogen present...... NO as a probe molecule to obtain detailed atomic-scale information on hydrotreating catalysts and the origins of activity differences. (C) 2011 Published by Elsevier Inc....

  11. Isotopic equilibrium constants of the deuterium exchange between HDO and H2S, H2Se and H2Te

    International Nuclear Information System (INIS)

    Marx, D.

    1959-11-01

    We have determined experimentally the equilibrium constant K of each of the following isotope exchanges: SH 2 + OHD ↔ SHD + OH 2 ; SeH 2 + OHD ↔ SeHD + OH 2 ; TeH 2 + OHD ↔ TeHD + OH 2 . In gaseous phase, statistical thermodynamics leads to the expression: K (Z OHD x Z RH 2 )/(Z OH 2 x Z RHD ) x e W/T (R being the elements S, Se or Te). Z, the partition functions, have been calculated and, through our experimental results, the constant W has been determined. Having obtained W, the equilibrium constant K has been calculated for a series of temperatures. (author) [fr

  12. Interaction of H2S with Calcium Permeable Channels and Transporters

    Directory of Open Access Journals (Sweden)

    Weihua Zhang

    2015-01-01

    Full Text Available A growing amount of evidence has suggested that hydrogen sulfide (H2S, as a gasotransmitter, is involved in intensive physiological and pathological processes. More and more research groups have found that H2S mediates diverse cellular biological functions related to regulating intracellular calcium concentration. These groups have demonstrated the reciprocal interaction between H2S and calcium ion channels and transporters, such as L-type calcium channels (LTCC, T-type calcium channels (TTCC, sodium/calcium exchangers (NCX, transient receptor potential (TRP channels, β-adrenergic receptors, and N-methyl-D-aspartate receptors (NMDAR in different cells. However, the understanding of the molecular targets and mechanisms is incomplete. Recently, some research groups demonstrated that H2S modulates the activity of calcium ion channels through protein S-sulfhydration and polysulfide reactions. In this review, we elucidate that H2S controls intracellular calcium homeostasis and the underlying mechanisms.

  13. AOI [3] High-Temperature Nano-Derived Micro-H2 and - H2S Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sabolsky, Edward M. [West Virginia Univ., Morgantown, WV (United States)

    2014-08-01

    The emissions from coal-fired power plants remain a significant concern for air quality. This environmental challenge must be overcome by controlling the emission of sulfur dioxide (SO2) and hydrogen sulfide (H2S) throughout the entire coal combustion process. One of the processes which could specifically benefit from robust, low cost, and high temperature compatible gas sensors is the coal gasification process which converts coal and/or biomass into syngas. Hydrogen (H2), carbon monoxide (CO) and sulfur compounds make up 33%, 43% and 2% of syngas, respectively. Therefore, development of a high temperature (>500°C) chemical sensor for in-situ monitoring of H2, H2S and SO22 levels during coal gasification is strongly desired. The selective detection of SO2/H2S in the presence of H2, is a formidable task for a sensor designer. In order to ensure effective operation of these chemical sensors, the sensor system must inexpensively function within harsh temperature and chemical environment. Currently available sensing approaches, which are based on gas chromatography, electrochemistry, and IR-spectroscopy, do not satisfy the required cost and performance targets. This work focused on the development microsensors that can be applied to this application. In order to develop the high- temperature compatible microsensor, this work addressed various issues related to sensor stability, selectivity, and miniaturization. In the research project entitled “High-Temperature Nano-Derived Micro-H2 and -H2S Sensors”, the team worked to develop micro-scale, chemical sensors and sensor arrays composed of nano-derived, metal-oxide composite materials to detect gases like H2, SO2, and H2S within high-temperature environments (>500°C). The research was completed in collaboration with NexTech Materials, Ltd. (Lewis Center, Ohio). Nex

  14. Human organic cation transporter 2 (hOCT2): Inhibitor studies using S2-hOCT2 cells

    International Nuclear Information System (INIS)

    Chiba, Shoetsu; Ikawa, Toru; Takeshita, Hiroshi; Kanno, Sanae; Nagai, Tomonori; Takada, Meri; Mukai, Toshiji; Wempe, Michael F.

    2013-01-01

    Highly expressed in kidney and located on the basolateral membrane, human organic cation transporter 2 (hOCT2) can transport various compounds (i.e. drugs and toxins) into the proximal tubular cell. Using cultured proximal tubule cells stably expressing hOCT2 (i.e. S2-hOCT2 cells), we sought to probe different compound classes (e.g. analgesics, anti-depressants, anti-psychotics, disinfectant, herbicides, insecticides, local anesthetic, muscarinic acetylcholine receptor antagonist, sedatives, steroid hormone, stimulants and toxins) for their ability to inhibit 14 C-TEA uptake, a prototypical OCT2 substrate. Aconitine, amitriptyline, atropine, chlorpyrifos, diazepam, fenitrothion, haloperidol, lidocaine, malathion, mianserin, nicotine and triazolam significantly inhibited 14 C-TEA uptake; IC 50 values were 59.2, 2.4, 2.0, 20.7, 32.3, 13.2, 32.5, 104.6, 71.1, 17.7, 52.8 and 65.5 μM, respectively. In addition, aconitine, amitriptyline, atropine, chlorpyrifos, fenitrothion, haloperidol, lidocaine, and nicotine displayed competitive inhibition with K i values of 145.6, 2.5, 2.4, 24.8, 16.9, 51.6, 86.8 and 57.7 μM, respectively. These in vitro data support the notion that compounds pertaining to a wide variety of different drug classes have the potential to decrease renal clearance of drugs transported via hOCT2. Consequently, these data warrant additional studies to probe hOCT2 and its role to influence drug pharmacokinetics

  15. Poisoning of Ni-Based anode for proton conducting SOFC by H2S, CO2, and H2O as fuel contaminants

    Science.gov (United States)

    Sun, Shichen; Awadallah, Osama; Cheng, Zhe

    2018-02-01

    It is well known that conventional solid oxide fuel cells (SOFCs) based on oxide ion conducting electrolyte (e.g., yttria-stabilized zirconia, YSZ) and nickel (Ni) - ceramic cermet anodes are susceptible to poisoning by trace amount of hydrogen sulfide (H2S) while not significantly impacted by the presence of carbon dioxide (CO2) and moisture (H2O) in the fuel stream unless under extreme operating conditions. In comparison, the impacts of H2S, CO2, and H2O on proton-conducting SOFCs remain largely unexplored. This study aims at revealing the poisoning behaviors caused by H2S, CO2, and H2O for proton-conducting SOFCs. Anode-supported proton-conducting SOFCs with BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb anode and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode as well as Ni-BZCYYb/BZCYYb/Ni-BZCYYb anode symmetrical cells were subjected to low ppm-level H2S or low percentage-level CO2 or H2O in the hydrogen fuel, and the responses in cell electrochemical behaviors were recorded. The results suggest that, contrary to conventional SOFCs that show sulfur poisoning and CO2 and H2O tolerance, such proton-conducting SOFCs with Ni-BZCYYb cermet anode seem to be poisoned by all three types of "contaminants". Beyond that, the implications of the experimental observations on understanding the fundamental mechanism of anode hydrogen electrochemical oxidation reaction in proton conducting SOFCs are also discussed.

  16. H2S cracking resistance of type 420 stainless steel tubulars

    International Nuclear Information System (INIS)

    Klein, L.J.

    1984-01-01

    Type 420 stainless steel (13Cr) production tubing is being used successfully in deep sour gas wells in the Tuscaloosa Trend. Despite their reputation for poor H 2 S cracking resistance in laboratory tests, 12-13% Cr steels continue to perform well in sour environments. NACE Tensile Test and Shell bent beam test results indicate Type 420 is more resistant to H 2 S cracking than Type 410, but is not as resistant as carbon steel, at to 586-690 MPa (85-100 ksi) yield strength level. In addition to evaluating Type 420 stainless steel in the standard NACE Tensile and Shell bent beam tests, the effects on cracking tendency of chloride concentration, pH, and H 2 S gas concentration in the NACE Test solution were also examined. Type 420 appears to be more resistant to H 2 S cracking than is indicated by standard laboratory tests, at least in low H 2 S level sour environments

  17. H2S mediated thermal and photochemical methane activation

    Science.gov (United States)

    Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric

    2013-01-01

    Sustainable, low temperature methods of natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) in mixture with methane, CH4, altogether deemed as sub-quality or “sour” gas. We propose a unique method for activating this “sour” gas to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3, and an energy carrier, such as H2. For this purpose, we computationally investigated H2S mediated methane activation to form a reactive CH3SH species via direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4+H2S complex results in a barrier-less relaxation via a conical intersection to form a ground state CH3SH+H2 complex. The resulting CH3SH can further be heterogeneously coupled over acidic catalysts to form higher hydrocarbons while the H2 can be used as a fuel. This process is very different from a conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced controllability over the process conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the currently industrially used methane steam reforming (SMR). PMID:24150813

  18. Specific IgE to peanut 2S albumin Ara h 7 has a discriminative ability comparable to Ara h 2 and 6.

    Science.gov (United States)

    Blankestijn, M A; Otten, H G; Suer, W; Weimann, A; Knol, E F; Knulst, A C

    2018-01-01

    Little is known on the clinical relevance of peanut 2S albumin Ara h 7. To investigate the discriminative ability of Ara h 7 in peanut allergy and assess the role of cross-reactivity between Ara h 2, 6 and Ara h 7 isoforms. Sensitization to recombinant peanut storage proteins Ara h 1, 2, 3, 6, and 7 was assessed using a line blot in sera from 40 peanut-tolerant and 40 peanut-allergic patients, based on food challenge outcome. A dose-dependent ELISA inhibition experiment was performed with recombinant Ara h 2, 6 and Ara h 7 isoforms. For Ara h 7.0201, an area under the ROC curve was found of 0.83, comparable to Ara h 2 (AUC 0.81) and Ara h 6 (AUC 0.85). Ara h 7 intensity values strongly correlated with those from Ara h 2 and 6 (r s = 0.81). Of all patients sensitized to 2S albumins Ara h 2, 6, or 7, the majority was co-sensitized to all three (n = 24, 68%), although mono-sensitization to either 2S albumin was also observed in selected patients (Ara h 2: n = 6, 17%; Ara h 6: n = 2, 6%; Ara h 7: n = 2, 6%). Binding to Ara h 7.0101 could be strongly inhibited by Ara h 7.0201, but not the other way around. Specific IgE against Ara h 7.0201 has a predictive ability for peanut allergy similar to Ara h 2 and 6 and possesses unique IgE epitopes as well as epitopes shared between the other Ara h 7 isoform and Ara h 2 and 6. While co-sensitization to all three 2S albumins is most common, mono-sensitization to either Ara h 2, 6, or 7 occurs in selected patients, leading to a risk of misdiagnosis when testing for a single 2S albumin. © 2017 John Wiley & Sons Ltd.

  19. The roles of H2S and H2O2 in regulating AsA-GSH cycle in the leaves of wheat seedlings under drought stress.

    Science.gov (United States)

    Shan, Changjuan; Zhang, Shengli; Ou, Xingqi

    2018-01-25

    This paper investigated the roles of hydrogen sulfide (H 2 S) and hydrogen peroxide (H 2 O 2 ) and the possible relationship between them in regulating the AsA-GSH cycle in wheat leaves under drought stress (DS). Results showed that DS markedly increased the production of H 2 S and H 2 O 2 , the transcript levels and activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR); malondialdehyde (MDA) content; and electrolyte leakage (EL). Meanwhile, DS markedly reduced plant height and biomass. Above increases induced by drought stress except MDA content and EL were all suppressed by pretreatments with H 2 S synthesis inhibitor aminooxyaceticacid (AOA) and H 2 O 2 synthesis inhibitor diphenylene iodonium (DPI). Besides, pretreatments with AOA and DPI further significantly increased MDA content and EL and significantly reduced plant height and biomass under DS. DPI reduced the production of H 2 O 2 and H 2 S induced by DS. AOA also reduced the production of H 2 S and H 2 O 2 induced by DS. Pretreatments with NaHS + AOA and H 2 O 2 + DPI reversed above effects of AOA and DPI. Our results suggested that H 2 S and H 2 O 2 all participated in the up-regulation of AsA-GSH cycle in wheat leaves by DS and possibly affected each other.

  20. Biochars as Potential Adsorbers of CH4, CO2 and H2S

    Directory of Open Access Journals (Sweden)

    Sumathi Sethupathi

    2017-01-01

    Full Text Available Methane gas, as one of the major biogases, is a potential source of renewable energy for power production. Biochar can be readily used to purify biogas contaminants such as H2S and CO2. This study assessed the adsorption of CH4, H2S, and CO2 onto four different types of biochars. The adsorption dynamics of biochars were investigated in a fixed-bed column, by determining the breakthrough curves and adsorption capacities of biochars. The physicochemical properties of biochars were considered to justify the adsorption performance. The results showed that CH4 was not adsorbed well by the subjected biochars whereas CO2 and H2S were successfully captured. The H2S and CO2 breakthrough capacity were related to both the surface adsorption and chemical reaction. The adsorption capacity was in the following order: perilla > soybean stover > Korean oak > Japanese oak biochars. The simultaneous adsorption also leads to a competition of sorption sites. Biochars are a promising material for the biogas purification industry.

  1. Secondary ligand-directed assembly of Co(II) coordination polymers based on a pyridine carboxylate ligand

    International Nuclear Information System (INIS)

    Cao, Ke-Li; Zhang, Yi-Ping; Cai, Yi-Ni; Xu, Xiao-Wei; Feng, Yun-Long

    2014-01-01

    To investigate the influence of hydrogen bonds and secondary ligands on the structures and properties of the resulting frameworks, five new Co(II) compounds have been synthesized by the reactions of Co(II) salts and 3,5-bis(pyridin-4-ylmethoxy)benzoic acid (HL) with four rationally selected dicarboxylic acid ligands. Without secondary ligand, we got one compound [CoL 2 (H 2 O) 2 ] n ·2nH 2 O (1), which possesses a 1D chain structure. In the presence of ancillary ligands, namely, 1,3-adamantanedicarboxylic acid (H 2 adbc), terephthalic acid (H 2 tpa), thiophene-2,5-dicarboxylic acid (H 2 tdc) and 1,4-benzenedithioacetic acid (H 2 bdtc), four 3D structures [Co 2 L 2 (adbc)] n ·nH 2 O (2), [Co 2 L 2 (tpa)] n (3), [Co 2 L 2 (tdc)] n (4), [Co 2 L 2 (bdtc)(H 2 O)] n (5) were obtained, respectively. It can be observed from the architectures of 1–5 that hydrogen bonds and secondary ligands both have great effects on the spatial connective fashions, resulting in the formation of various dimensional compounds. The XRPD, TGA data of title polymers and the magnetic properties for 2 and 5 have also been investigated. - Graphical abstract: The structural differences show that the ancillary ligands have great effects on the spatial connective fashions, resulting in the formation of various dimensional compounds. - Highlights: • Five new Co(II) coordination polymers have been synthesized by solvothermal reactions based on 3,5-bis(pyridin-4-ylmethoxy)benzoic acid (HL). • The long-flexible ligand (HL) is a good candidate to produce interpenetrating architectures. • The secondary dicarboxylic acid ligands play important roles in the spatial connective fashions and the formation of various dimensional compounds. • The magnetism studies show that both 2 and 5 exhibit antiferromagnetic interactions

  2. The Role of Endogenous H(2)S in Cardiovascular Physiology

    DEFF Research Database (Denmark)

    Skovgaard, Nini; Gouliaev, Anja; Aalling, Mathilde

    2011-01-01

    Recent research has shown that the endogenous gas hydrogen sulphide (H(2)S) is a signalling molecule of considerable biological potential and has been suggested to be involved in a vast number of physiological processes. In the vascular system, H(2)S is synthesized from cysteine by cystathionine-...

  3. Study of H/sub 2/S emissions from a salt water marsh

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, A B; Maroulis, P J; Wilner, L A; Bandy, A R

    1981-01-01

    A gas chromatographic method was developed for measuring background levels of atmospheric H/sub 2/S. A detectivity of 0.02 ppBV (S/N=2) was achieved with a frequency of one sample per 8 min. A reduction of the detectivity to 0.005 ppBV was predicted with modest optimization effort. The technique was applied in a study of H/sub 2/s emissions from a salt water marsh. Large diurnal variations of the H/sub 2/S levels were observed that were relatively repeatable under similar meteorological conditions. The area averaged emission rate of h2s for one evening in July was estimated to be between 3 and 16 g S/m/sup 2//y. The emission rate was estimated to have decreased by a factor of at least 10 between 22 July and 13 December 1978. Atlantic Ocean air was found to be very low in H/sub 2/S content, typically less than 30 ppTV.

  4. AVALIAÇÃO DA EFICIÊNCIA DA MACRÓFITA HYMENACHNE GRUMOSA COMO ORGANISMO TESTE, EM DOIS SISTEMAS DE TRATAMENTO DE EFLUENTES, ATRAVÉS DE ENSAIOS ECOTOXICOLÓGICOS

    Directory of Open Access Journals (Sweden)

    Geani Mohr

    2015-08-01

    Full Text Available O trabalho teve como objetivo avaliar a eficiência da macrófita Hymenachne grumosa como teste para remoção de poluentes através de ensaios de toxicidade aguda de duas estações experimentais utilizando Daphnia magna Straus como organismo-teste. Desenho experimental 1 (PA-1, proveniente da Estação de Tratamento de Esgoto (ETE-UNISC, com Wetlands construídos (WC’s, entre abril e setembro de 2010. Já o desenho experimental 2 (PA-2 corresponde a um sistema de captação e tratamento de água em uma propriedade rural localizada em Vera Cruz, RS, entre setembro de 2013 e fevereiro de 2014. Os resultados para o PA-1 indicaram que o efluente bruto apresentou uma CE (I50% 48h de 51,3 ± 17,2%, correspondendo a uma amostra medianamente tóxica. Nos pontos P2, P3, P4 e P5 as amostras apresentaram-se pouco tóxicas. Para o PA-2, os resultados indicaram que o efluente bruto apresentou uma CE (I50% 48h de 8,1 ± 2,6%, correspondendo a uma amostra extremamente tóxica. Nos pontos P2 e P3 as amostras enquadraram-se como altamente e pouco tóxicas, respectivamente. No P4 os efluentes não apresentaram toxicidade. Do ponto de vista da ecotoxicologia, os resultados sugerem que o uso de H. grumosa como componente principal nos WC’s foi significativa, representando uma alternativa promissora para remover toxicidade de efluentes domésticos.

  5. Surface science models of CoMoS hydrodesulfurisation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, A.M.; De Beer, V.H.J.; Van Veen, J.A.R.; Niemantsverdriet, J.W. [Schuit Institute of Catalysis, Eindhoven University of Technology, Eindhoven (Netherlands)

    1997-07-01

    Characterization of supported catalysts with surface spectroscopic techniques is often limited due to restraints imposed by the support material. The use of flat conducting substrates as a model support offers a way to apply these techniques to their full potential. Such surface science models of silica and alumina supported CoMoS catalysts have been made by impregnating thin SiO{sub 2} and Al{sub 2}O{sub 3} films with a solution of nitrilotriacetic acid (NTA) complexes of cobalt and molybdenum. X-ray Photoelectron Spectroscopy (XPS) spectra indicate that the order in which cobalt and molybdenum transfer to the sulfided state is reversed with respect to oxidic Co and Mo systems prepared by conventional methods, implying that NTA complexation retards the sulfidation of cobalt to temperatures where MoS{sub 2} is already formed. Catalytic tests show that the CoMoS model catalysts exhibit activities for thiophene desulfurisation and product distributions similar to those of their high surface area counterparts. 25 refs.

  6. Investigation of the chemistry of liquid H{sub 2}S scavengers

    Energy Technology Data Exchange (ETDEWEB)

    Buhaug, Janne Bjoerntvedt

    2002-07-01

    The production of natural gas in the North Sea is facing a growing problem: contamination of the natural gas with dihydrogen sulfide, H{sub 2}S. As a gas reservoir is emptied, seawater containing sulfates is pumped into it, and the sulfates are reduced to dihydrogen sulfide by sulfate-reducing bacteria. Dihydrogen sulfide is then pumped up along with the oil, gas and water from the reservoir, causing severe corrosion of pipelines and contamination of the final natural gas product. Dihydrogen sulfide is extremely toxic, and in fields with especially large concentrations of H{sub 2}S this is a severe health risk for the platform workers. Hence, it is desirable to remove the dihydrogen sulfide at the earliest stage possible. There are four main methods for removing H{sub 2}S from natural gas: (1) Liquid scavengers, (2) Solid scavengers, (3) Liquid redox processes, (4) Amine / Claus catalyst. Liquid scavengers are widely used in the natural gas industry, especially at sites with relatively low concentrations of H{sub 2}S. As a rule of thumb, liquid scavengers are economically favourable at sites with a removal of less than 50 kg/day of H{sub 2}S. This thesis is concerned with the cyclic amine 1,3,5 -tris(2-hydroxyethyl)-1,3,5-triazinane, often referred to as Triazine. This is used in fields with relatively low concentration of H{sub 2}S and dominates the liquid scavenger market.

  7. Identification of Lactobacillus UFV H2b20 (probiotic strain using DNA-DNA hybridization Identificação de Lactobacillus UFV H2b20 (linhagem probiótica através de hibridização DNA-DNA

    Directory of Open Access Journals (Sweden)

    J.T. de Magalhães

    2008-09-01

    Full Text Available Sequence analyses of the 16S rDNA gene and DNA-DNA hybridization tests were performed for identification of the species of the probiotic Lactobacillus UFV H2b20 strain. Using these two tests, we concluded that this strain, originally considered Lact. acidophilus, should be classified as Lact. delbrueckii.Análise da seqüência do gene 16S rDNA e ensaios de hibridização DNA_DNA foram empregados para identificar a espécie da cepa probiótica Lactobacillus UFV H2b20. Empregando-se estes dois testes, concluímos que esta cepa, originalmente considerada Lact. acidophilus, deve ser classificada como Lact. delbrueckii.

  8. Synthesis and spectroscopic stereospecificity assay of the deuterated quinolizidine alkaloids (2S)-( sup 2 H)- and (2R)-( sup 2 H)-sparteine

    Energy Technology Data Exchange (ETDEWEB)

    Ebner, T.; Meese, C.O. (Fischer-Bosch Inst. fuer Klinische Pharmakologie, Stuttgart (Germany, F.R.)); Rebell, J. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Organische Chemie); Fischer, P. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Organische Chemie Fischer-Bosch Inst. fuer Klinische Pharmakologie, Stuttgart (Germany, F.R.))

    1989-04-01

    Borohydride reduction of the (+)-1,2-dehydrosparteinium salts proceeds almost exclusively from the Si side, yielding, respectively, the stereoselectively (2S)({beta})-deuterated (-)-sparteine and the (2R)({alpha})-deuterated (-)-sparteine. Stereo-chemistry and isotopic purity of the deuterium label ({>=}98%) are established unequivocally by {sup 1}H, {sup 2}H and {sup 13}C NMR spectroscopy. (author).

  9. A Method for the Simultaneous Cleansing of H2S and SO2

    Directory of Open Access Journals (Sweden)

    Dzhamal R. Uzun

    2016-01-01

    Full Text Available A method for the simultaneous electrochemical purification of hydrogen sulfide and sulfur dioxide from sea water or industrial wastes is proposed. Fundamentally the method is based on the electrochemical affinity of the pair H2S and SO2. The reactions (oxidation of H2S and reduction of SO2 proceed on а proper catalyst in a flow reactor, without an external power by electrochemical means. The partial curves of oxidation of H2S and reduction of SO2 have been studied electrochemically on different catalysts. Following the additive principle the rate of the process has been found by intersection of the curves. The overall process rate has been studied in a flow type reactor. Similar values of the process rate have been found and these prove the electrochemical mechanism of the reactions. As a result the electrochemical method at adequate conditions is developed. The process is able to completely convert the initial reagents (concentrations CH2S, SO2=0, which is difficult given the chemical kinetics.

  10. 2S protein Ara h 7.0201 has unique epitopes compared to other Ara h 7 isoforms and is comparable to 2S proteins Ara h 2 and 6 in basophil degranulation capacity.

    Science.gov (United States)

    Hayen, S M; Ehlers, A M; den Hartog Jager, C F; Garssen, J; Knol, E F; Knulst, A C; Suer, W; Willemsen, L E M; Otten, H G

    2018-07-01

    Screening for specific IgE against 2S albumin proteins Ara h 2 and 6 has good positive predictive value in diagnosing peanut allergy. From the third 2S member Ara h 7, 3 isoforms have been identified. Their allergenicity has not been elucidated. This study investigated the allergenicity of Ara h 7 isoforms compared to Ara h 2 and 6. Sensitization of 15 DBPCFC-confirmed peanut-allergic patients to recombinant Ara h 2.0201, Ara h 6.01 and isoforms of recombinant Ara h 7 was determined by IgE immunoblotting strips. A basophil activation test (BAT) was performed in 9 patients to determine IgE-cross-linking capacities of the allergens. Sensitivity to the allergens was tested in 5 patients who were sensitized to at least 1 Ara h 7 isoform, by a concentration range in the BAT. 3D prediction models and sequence alignments were used to visualize differences between isoforms and to predict allergenic epitope regions. Sensitization to Ara h 7.0201 was most frequent (80%) and showed to be equally potent as Ara h 2.0201 and 6.01 in inducing basophil degranulation. Sensitization to Ara h 7.0201 together with Ara h 2.0201 and/or 6.01 was observed, indicating the presence of unique epitopes compared to the other 2 isoforms. Differences between the 3 Ara h 7 isoforms were observed in C-terminal cysteine residues, pepsin and trypsin cleavage sites and 3 single amino acid substitutions. The majority of peanut-allergic patients are sensitized to isoform Ara h 7.0201, which is functionally as active as Ara h 2.0201 and 6.01. Unique epitopes are most likely located in the C-terminus or an allergenic loop region which is a known allergenic epitope region for Ara h 2.0201 and 6.01. Due to its unique epitopes and allergenicity, it is an interesting candidate to improve the diagnostic accuracy for peanut allergy. © 2018 The Authors. Clinical & Experimental Allergy Published by John Wiley & Sons Ltd.

  11. Formation of H(2s) atoms by excitation in 10-100 keV H+-H collisions

    International Nuclear Information System (INIS)

    Higgins, D.P.; Geddes, J.; Gilbody, H.B.

    1996-01-01

    Cross sections for 2s excitation of H atoms in 10-100 keV H + -H collisions have been determined using a modulated crossed-beam technique. The measurements have been based on observations of the Lyman alpha radiation emitted during electric-field-induced decay of the metastable H(2s) collision products. The results extend the range of the 5-26 keV cross sections measured by Morgan and co-workers to intermediate energies where theoretical predictions based on close-coupling methods are known to be strongly dependent on the choice of the expansion basis. The present cross sections pass through a broad maximum at about 40 keV. Over the range 5-100 keV the available experimental data exhibit an undulatory structure similar to that predicted by some close-coupling calculations but good quantitative agreement is very limited. Close-coupling calculations which employ large basis sets and include a large number of projectile states at the expense of target states are shown to agree less satisfactorily with experiment than those which include only the dominant 1s capture projectile channel. (Author)

  12. The crystal structure of Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Verena; Schlosser, Marc; Pfitzner, Arno [Regensburg Univ. (Germany). Inst. fuer Anorganische Chemie

    2016-08-01

    A reinvestigation of the alkali metal thiosulfates has led to the new phase Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O. At first cesium thiosulfate monohydrate was obtained as a byproduct of the synthesis of Cs{sub 4}In{sub 2}S{sub 5}. Further investigations were carried out using the traditional synthesis reported by J. Meyer and H. Eggeling. Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O crystallizes in transparent, colorless needles. The crystal structure of the title compound was determined by single crystal X-ray diffraction at room temperature: space group C2/m (No. 12), unit cell dimensions: a = 11.229(4), b = 5.851(2), c = 11.260(5) Aa, β = 95.89(2) , with Z = 4 and a cell volume of V = 735.9(5) Aa{sup 3}. The positions of all atoms including the hydrogen atoms were located in the structure refinement. Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O is isotypic with Rb{sub 2}S{sub 2}O{sub 3}.H{sub 2}O. Isolated tetrahedra [S{sub 2}O{sub 3}]{sup 2-} are coordinated by the alkali metal cations, and in addition they serve as acceptors for hydrogen bonding. For both Cs atoms the shortest distances are observed to oxygen atoms of the S{sub 2}O{sub 3}{sup 2-} anions whereas the terminating sulfur atom has its shortest contacts to the water hydrogen atoms. Thus, an extended hydrogen bonding network is formed. The title compound has also been characterized by IR spectroscopy. IR spectroscopy reveals the vibrational bands of the water molecules at 3385 cm{sup -1}. They show a red shift in the OH stretching and bending modes as compared to free water. This is due both to the S..H hydrogen bonding and to the coordination of H{sub 2}O molecules to the cesium atoms.

  13. Measuring the density and viscosity of H2S-loaded aqueous methyldiethanolamine solution

    International Nuclear Information System (INIS)

    Shokouhi, Mohammad; Ahmadi, Reza

    2016-01-01

    Highlights: • Measurement solubility of H 2 S in 46.78 mass% MDEA aqueous solutions. • Measurement density of H 2 S loaded of MDEA aqueous solution. • Measurement viscosity of H 2 S loaded of MDEA aqueous solution. • Correlation of the density and viscosity of H 2 S loaded of MDEA aqueous solution using modified setchenow equation. - Abstract: The density and viscosity of H 2 S-loaded aqueous 46.78 mass% methyldiethanolamine solution were experimentally measured accompanied with the solubility of H 2 S at temperatures (313.15, 328.15 and 343.15) K, pressures from vapor pressure of fresh solution up to 1.0 MPa and loadings up to 1.00 mol of H 2 S per 1 mol of amine. All experimental trials have been carried out using the new setup developed in our laboratory. It was observed that both density and viscosity of mixtures decrease by increasing temperature and density increase by increasing acid gas solubility (loading) by about 4.7%, whereas viscosity has a complicated behavior with H 2 S solubility. Viscosity decreases by increasing acid gas solubility (loading) at 313.15 K by about 20.6% and at 328.15 K by about 15.0%, but it is comparable at 343.15 K in terms of H 2 S solubility. Finally, the experimental density and viscosity data correlated using Modified Setchenow equation.

  14. Broadening of spectral lines of CO2, N2O , H2CO, HCN, and H2S by pressure of gases dominant in planetary atmospheres (H2, He and CO2)

    Science.gov (United States)

    Samuels, Shanelle; Gordon, Iouli; Tan, Yan

    2018-01-01

    HITRAN1,2 is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in planetary atmospheres. The goal of this project is to add to the potential of the HITRAN database towards the exploration of the planetary atmospheres by including parameters describing broadening of spectral lines by H2, CO2, and He. These spectroscopic data are very important for the study of the hydrogen and helium-rich atmospheres of gas giants as well as rocky planets with volcanic activities, including Venus and Mars, since their atmospheres are dominated by CO2. First step in this direction was accomplished by Wilzewski et al.3 where this was done for SO2, NH3, HF, HCl, OCS and C2H2. The molecules investigated in this work were CO2, N2O, H2CO, HCN and H2S. Line-broadening coefficients, line shifts and temperature-dependence exponents for transitions of these molecules perturbed by H2, CO2 and He have been assembled from available peer-reviewed experimental and theoretical sources. The data was evaluated and the database was populated with these data and their extrapolations/interpolations using semi-empirical models that were developed to this end.Acknowledgements: Financial support from NASA PDART grant NNX16AG51G and the Smithsonian Astrophysical Observatory Latino Initiative Program from the Latino Initiatives Pool, administered by the Smithsonian Latino Center is gratefully acknowledged.References: 1. HITRAN online http://hitran.org/2. Gordon, I.E., Rothman, L.S., Hill, C., Kochanov, R.V., Tan, Y., et al., 2017. The HITRAN2016 Molecular Spectroscopic Database. J. Quant. Spectrosc. Radiat. Transf. doi:10.1016/j.jqsrt.2017.06.0383. Wilzewski, J.S., Gordon, I.E., Kochanov, R. V., Hill, C., Rothman, L.S., 2016. H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2. J. Quant. Spectrosc. Radiat

  15. Microwave-assisted synthesis of NiS2 nanostructures for supercapacitors and cocatalytic enhancing photocatalytic H2 production

    Science.gov (United States)

    Pang, Huan; Wei, Chengzhen; Li, Xuexue; Li, Guochang; Ma, Yahui; Li, Sujuan; Chen, Jing; Zhang, Jiangshan

    2014-01-01

    Uniform NiS2 nanocubes are successfully synthesized with a microwave-assisted method. Interestingly, NiS2 nanocubes, nanospheres and nanoparticles are obtained by controlling microwave reaction time. NiS2 nanomaterials are primarily applied to supercapacitors and cocatalytic enhancing photocatalytic H2 production. Different morphologies of NiS2 nanostructures show different electrochemical and cocatalytic enhancing H2 production activities. Benefited novel nanostructures, NiS2 nanocube electrodes show a large specific capacitance (695 F g-1 at 1.25 A g-1) and excellent cycling performance (the retention 93.4% of initial specific capacitance after 3000 cycles). More importantly, NiS2 nanospheres show highly cocatalytic enhancing photocatalytic for H2 evolution, in which the photocatalytic H2 production is up to 3400 μmol during 12 hours under irradiation of visible light (λ>420 nm) with an average H2 production rate of 283 μmol h-1.

  16. Stereospecific ligands and their complexes. VI. The crystal structure of (S,S-ethylenediamine-N,N’-di-2-propanoic acid hydrochloride, (S,S-H2eddp•HCl

    Directory of Open Access Journals (Sweden)

    VERICA V. GLODJOVIĆ

    2011-07-01

    Full Text Available (S,S-Ethylenediamine-N,N’-di-2-propanoic acid hydrochloride, (S,S-H2eddp·HCl, was prepared and its crystal structure determined. The compound was characterized by infrared and 1H- and 13C-NMR spectroscopy. It forms P1 in the space group of a triclinic crystal system with a = 5.3902(2 Å, b = 5.8967(2 Å, c = 10.3319(2 Å, a = 99.625(2°, b = 91.645(2°, g = 109.995(2° and Z = 1.

  17. Factors affecting temporal H2S emission at construction and demolition (C&D) debris landfills.

    Science.gov (United States)

    Xu, Qiyong; Townsend, Timothy

    2014-02-01

    Odor problems associated with H2S emissions often result in odor complaints from nearby residents of C&D debris landfills, especially in the early morning. As part of a field study conducted on H2S removal ability using different cover materials, daily and seasonal H2S emissions through a soil cover layer were monitored at a C&D debris landfill to investigate factors affecting H2S emissions. H2S emission rates were not a constant, but varied seasonally, with an average emission rate of 4.67×10(-6)mgm(-2)s(-1). During a the 10-month field study, as the H2S concentration increased from 140ppm to about 3500ppm underneath the cover soil in the testing cell, H2S emissions ranged from zero to a maximum emission rate of 1.24×10(-5)mgm(-2)s(-1). Continuous emission monitoring indicated that H2S emissions even changed over time throughout the day, generally increasing from morning to afternoon, and were affected by soil moisture and temperature. Laboratory experiments were also conducted to investigate the effects of H2S concentration and cover soil moisture content on H2S emissions. The results showed that increased soil moisture reduced H2S emissions by retarding H2S migration through cover soil and dissolving H2S into soil water. The field study also indicated that due to atmospheric dispersion, high H2S emissions may not cause odor problems. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. ZnO-carbon nanofibers for stable, high response, and selective H2S sensors.

    Science.gov (United States)

    Zhang, Jitao; Zhu, Zijian; Chen, Changmiao; Chen, Zhi; Cai, Mengqiu; Qu, Baihua; Wang, Taihong; Zhang, Ming

    2018-07-06

    Hydrogen sulfide (H 2 S), as a typical atmospheric pollutant, is neurotoxic and flammable even at a very low concentration. In this study, we design stable H 2 S sensors based on ZnO-carbon nanofibers. Nanofibers with 30.34 wt% carbon are prepared by a facial electrospinning route followed by an annealing treatment. The resulting H 2 S sensors show excellent selectivity and response compared to the pure ZnO nanofiber H 2 S sensors, particularly the response in the range of 102-50 ppm of H 2 S. Besides, they exhibited a nearly constant response of approximately 40-20 ppm of H 2 S over 60 days. The superior performance of these H 2 S sensors can be attributed to the protection of carbon, which ensures the high stability of ZnO, and oxygen vacancies that improve the response and selectivity of H 2 S. The good performance of ZnO-carbon H 2 S sensors suggests that composites with oxygen vacancies prepared by a facial electrospinning route may provide a new research strategy in the field of gas sensors, photocatalysts, and semiconductor devices.

  19. Calcio sérico total y calcio corregido como predictores de severidad en pancreatitis aguda

    Directory of Open Access Journals (Sweden)

    A.A. Gutiérrez-Jiménez

    2014-01-01

    Conclusiones: El CT y CCA tomados en las primeras 24 h son útiles como predictores de severidad en pancreatitis aguda, con valores de S y predictivos comparables o superiores a los de las escalas pronósticas tradicionales.

  20. Role of Elemental Sulfur in Forming Latent Precursors of H2S in Wine.

    Science.gov (United States)

    Jastrzembski, Jillian A; Allison, Rachel B; Friedberg, Elle; Sacks, Gavin L

    2017-12-06

    The level of hydrogen sulfide (H 2 S) can increase during abiotic storage of wines, and potential latent sources of H 2 S are still under investigation. We demonstrate that elemental sulfur (S 0 ) residues on grapes not only can produce H 2 S during fermentation but also can form precursors capable of generating additional H 2 S after bottle storage for 3 months. H 2 S could be released from S 0 -derived precursors by addition of a reducing agent (TCEP), but not by addition of strong brine to induce release of H 2 S from metal sulfide complexes. The size of the TCEP-releasable pool varied among yeast strains. Using the TCEP assay, multiple polar S 0 -derived precursors were detected following normal-phase preparative chromatography. Using reversed-phase liquid chromatography and high-resolution mass spectrometry, we detected an increase in the levels of diglutathione trisulfane (GSSSG) and glutathione disulfide (GSSG) in S 0 -fermented red wine and an increase in the levels of glutathione S-sulfonate (GSSO 3 - ) and tetrathionate (S 4 O 6 2- ) in S 0 -fermented white wine as compared to controls. GSSSG, but not S 4 O 6 2- , was shown to evolve H 2 S in the presence of TCEP. Pathways for the formation of GSSSG, GSSG, GSSO 3 - , and S 4 O 6 2- from S 0 are proposed.

  1. Radioprotective role of H2S/CSE pathway in Chang liver cells

    International Nuclear Information System (INIS)

    Pan Yan; Ye Shuang; Yuan Dexiao; Zhang Jianghong; Bai Yang; Shao Chunlin

    2012-01-01

    Radiation-induced liver cell damage may be life-threatening. Here, we investigated whether hydrogen sulfide (H 2 S)/cystathionine γ-lyase (CSE) pathway could serve the protective role toward radiation in normal human liver cells. Our data showed that pretreatment of cells with H 2 S donor, sodium hydrosulfide (NaHS) significantly attenuated radiation induced micronuclei formation and improved cell viability. However, the use of DL-propargylglycine (PPG), a potent inhibitor of CSE, markedly enhanced the cell-killing effect induced by radiation. Exposure of cells to 2 Gy γ-radiation led to significant increases of the endogenous H 2 S content. The mRNA and protein expressions of CSE also increased after radiation in a time-dependent manner, while the expression of cystathionine β-synthase (CBS), another endogenous H 2 S synthetase, did not change significantly. Notably, radiation induced production of reactive oxygen species (ROS) was significantly reversed by the pretreatment of NaHS, while blockage of CSE activity resulted in an enhanced ROS production in irradiated cells. Moreover, NaHS markedly suppressed radiation-induced phosphorylation of P53, decrease of Bcl-2/Bax, and activity of nuclear factor kappaB (NF-κB). In conclusion, our finding demonstrates that H 2 S/CSE pathway plays a radioprotection role by inhibiting radiation-induced ROS production, P53 phosphorylation, NF-κB activation and decrease of Bcl-2/Bax, indicating that modulation of H 2 S may be a novel protection strategy for liver radiation injury in radiotherapy.

  2. Electronic properties of in-plane phase engineered 1T'/2H/1T' MoS2

    Science.gov (United States)

    Thakur, Rajesh; Sharma, Munish; Ahluwalia, P. K.; Sharma, Raman

    2018-04-01

    We present the first principles studies of semi-infinite phase engineered MoS2 along zigzag direction. The semiconducting (2H) and semi-metallic (1T') phases are known to be stable in thin-film MoS2. We described the electronic and structural properties of the infinite array of 1T'/2H/1T'. It has been found that 1T'phase induced semi-metallic character in 2H phase beyond interface but, only Mo atoms in 2H phase domain contribute to the semi-metallic nature and S atoms towards semiconducting state. 1T'/2H/1T' system can act as a typical n-p-n structure. Also high holes concentration at the interface of Mo layer provides further positive potential barriers.

  3. Isoreticular rare earth fcu-MOFs for the selective removal of H 2 S from CO 2 containing gases

    KAUST Repository

    Bhatt, Prashant

    2017-05-04

    In this work, we present the implementation of reticular chemistry and the molecular building block approach to unveil the appropriateness of Rare Earth (RE) based Metal-Organic Frameworks (MOFs) with fcu topology for H2S removal applications. Markedly, RE-fcu-MOFs, having different pore apertures sizes in the range of 4.7-6.0 Å and different functionalities, showed excellent properties for the removal of H2S from CO2 and CH4 containing gases such as natural gas, biogas and landfill gas. A series of cyclic mixed gas breakthrough experiments were carried out on three isoreticular fcu-MOFs, containing linkers of different lengths (between 8.4 and 5 Å), by using simulated natural gas mixture containing CO2/H2S/CH4 (5%/5%/90%) under different adsorption and regeneration conditions. The fcu-MOF platform has good H2S removal capacity with a high H2S/CO2 selectivity, outperforming benchmark materials like activated carbon and Zeolites in many aspects. The comparison of H2S removal performance with the related structures of the RE-fcu-MOFs provides insightful information to shed light on the relationship between the structural features of the MOF and its associated H2S separation properties. The excellent H2S/CO2 and H2S/CH4 selectivity of these materials offer great prospective for the production of pure H2S, with acceptable levels of CO2for Claus process to produce elemental sulfur.

  4. Obtención de nuevos materiales híbridos orgánico-inorgánicos fotosensibles utilizables como láseres de colorante en estado sólido

    Directory of Open Access Journals (Sweden)

    García, O.

    2004-04-01

    Full Text Available The synthesis of new materials of hybrid character (organic-inorganic doped with dyes results highly attractive like active medium in solid state laser in which the excellent thermal properties of the inorganic glasses with the excellent optic properties of the polymeric materials could be combined. Through a simultaneous synthesis process of sol-gel policondensation of the inorganic TEOS during the free radical polymerization of the organic part (vinylic or acrylic monomers with OH groups, since the presence of this -OH side groups in the organic monomer can participate in the policondensation process of silanols, hybrids monoliths were able to be obtained as solid-state dye laser matrices. The synthesis and characterization of new hybrid matrices were carried out incorporating pirromethene 567 (PM567 into polymers of 2-hydroxyethyl methacrylate (HEMA and copolymers of HEMA and methyl methacrylate (MMA with different weight proportions of the inorganic component, tetraethoxysilane (TEOS. The first results obtained with this new materials are indicave that the addition of low proportions of TEOS into the polymer P(HEMA/MMA 1/1 increases its thermal stability reducing the thermal degradation of the dye and, consequently, improving significantly its laser action. In fact, some of the results achieved with these new materials represent the best photostability reached to date for PM567 incorporated into inorganic and hybrid materials and, taking into account the experimental pumping conditions, improve or at least, compare well, with the lasing properties of the dye embedded in other host polymeric matrices.

    La síntesis de nuevos materiales de carácter híbrido (orgánico-inorgánico dopados con colorantes resultan altamente atractivos como medio activo en láseres de estado sólido ya que permiten combinar las excelentes propiedades térmicas que presentan los vidrios inorgánicos con las excelentes propiedades ópticas que presentan los

  5. Microwave-assisted synthesis of NiS2 nanostructures for supercapacitors and cocatalytic enhancing photocatalytic H2 production

    Science.gov (United States)

    Pang, Huan; Wei, Chengzhen; Li, Xuexue; Li, Guochang; Ma, Yahui; Li, Sujuan; Chen, Jing; Zhang, Jiangshan

    2014-01-01

    Uniform NiS2 nanocubes are successfully synthesized with a microwave-assisted method. Interestingly, NiS2 nanocubes, nanospheres and nanoparticles are obtained by controlling microwave reaction time. NiS2 nanomaterials are primarily applied to supercapacitors and cocatalytic enhancing photocatalytic H2 production. Different morphologies of NiS2 nanostructures show different electrochemical and cocatalytic enhancing H2 production activities. Benefited novel nanostructures, NiS2 nanocube electrodes show a large specific capacitance (695 F g−1 at 1.25 A g−1) and excellent cycling performance (the retention 93.4% of initial specific capacitance after 3000 cycles). More importantly, NiS2 nanospheres show highly cocatalytic enhancing photocatalytic for H2 evolution, in which the photocatalytic H2 production is up to 3400 μmol during 12 hours under irradiation of visible light (λ>420 nm) with an average H2 production rate of 283 μmol h−1. PMID:24389929

  6. Novel 2D or 3D alkaline-earth metal sulfonate-phosphonates based on [O 3S-C 2H 4-PO 3H] 2- ligand

    Science.gov (United States)

    Du, Zi-Yi; Wen, He-Rui; Xie, Yong-Rong

    2008-11-01

    Three novel alkaline-earth metal sulfonate-phosphonates based on [O 3S-C 2H 4-PO 3H] 2- ligand, namely, [Ca(O 3SC 2H 4PO 3H)(H 2O) 2] ( 1), [Sr(O 3SC 2H 4PO 3H)] ( 2) and [Ba 2(O 3SC 2H 4PO 3H) 2] ( 3), have been synthesized by hydrothermal reactions. They represent the first structurally characterized alkaline-earth metal complexes of phosphonic acid attached with a sulfonate group. The structure of compound 1 features a 2D layer based on 1D chains of [Ca 2(PO 3) 2] bridged by -CH 2-CH 2-SO 3- groups. Compounds 2 and 3 show pillar-layer architecture based on two different inorganic layers linked by -CH 2-CH 2- groups. The inorganic layer in compound 2 features a 1D chain of edge-sharing SrO 8 polyhedra whereas that in compound 3 features an edge-sharing Ba 2O 14 di-polyhedral unit which is further corner-shared with four neighboring ones. The [O 3S-C 2H 4-PO 3H] 2- ligand shows diverse coordination modes in the three alkaline-earth metal sulfonate-phosphonates.

  7. Adsorption of H2S molecule on TiO2/Au nanocomposites: A density functional theory study

    Directory of Open Access Journals (Sweden)

    Amirali Abbasi

    2017-01-01

    Full Text Available The adsorption of hydrogen sulfide molecule on undoped and N-doped TiO2/Au nanocomposites was investigated by density functional theory (DFT calculations. The results showed that the adsorption energies of H2S on the nanocomposites follow the order of 2N doped (Ti site>N-doped (Ti site>Undoped (Ti site. The structural properties including bond lengths, angles and adsorption energies and electronic properties in view of the projected density of states (PDOSs and molecular orbitals (MOs were analyzed in detail. The results indicated that the interaction between H2S molecule and N-doped TiO2/Au nanocomposite is stronger than that between H2S and undoped nanocomposite, suggesting that N-doping helps to strengthen the interaction of H2S with TiO2/Au nanocomposite. Mulliken population analysis was conducted to analyze the charge transfer between the nanocomposite and H2S molecule. Although H2S molecule has no significant interaction with undoped nanocomposite, it tends to be strongly adsorbed on the N-doped nanocomposite. The results also suggest that the two doped nitrogen atoms in TiO2 greatly strengthen the adsorption process, being a helpful procedure to help in the design and development of improved sensor devices for H2S detection.

  8. Metal organic framework absorbent platforms for removal of co2 and h2s from natural gas

    KAUST Repository

    Belmabkhout, Youssef; Eddaoudi, Mohamed; Adil, Karim; Cadiau, Amandine; Bhatt, Prashant M.

    2016-01-01

    Provided herein are metal organic frameworks comprising metal nodes and N-donor organic ligands which have high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Methods include capturing one or more of H2S, H2O, and CO2 from fluid compositions, such as natural gas.

  9. Metal organic framework absorbent platforms for removal of co2 and h2s from natural gas

    KAUST Repository

    Belmabkhout, Youssef

    2016-10-13

    Provided herein are metal organic frameworks comprising metal nodes and N-donor organic ligands which have high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Methods include capturing one or more of H2S, H2O, and CO2 from fluid compositions, such as natural gas.

  10. Investigation of H2S and CO2 Removal from Gas Streams Using Hollow Fiber Membrane Gas–liquid Contactors

    Directory of Open Access Journals (Sweden)

    S. M. Mirfendereski

    2017-07-01

    Full Text Available Chemical absorption of H2S and CO2 from CH4 was carried out in a polypropylene porous asymmetric hollow fiber membrane contactor (HFMC. A 0.5 mol L–1 aqueous solution of methyldiethanolamine (MDEA was used as chemical absorbent solution. Effects of gas flow rate, liquid flow rate, H2S concentration and CO2 concentration on the H2S outlet concentrations and CO2 removal percentage were investigated. The results showed that the removal of H2S with aqueous solution of MDEA was very high and indicated almost total removal of H2S. Experimental results also indicated that the membrane contactor was very efficient in the removal of trace H2S at high gas/ liquid flow ratio. The removal of H2S was almost complete with a recovery of more than 96 %. Using feed gas mixtures containing 5000 ppm H2S with CO2 concentrations in the range of 4–12 vol.%, the outlet H2S concentration of less than 1.0 ppm was attained with less than 4.0 vol.% of CO2 permeated and absorbed.

  11. Materiales híbridos moleculares orgánicos-inorgánicos: síntesis y aplicación como electrodos en baterías recargables de litio

    Directory of Open Access Journals (Sweden)

    Torres-Gómez, G.

    2000-06-01

    Full Text Available A novel family of molecular hybrid materials based on electroactive inorganic species dispersed in conducting organic polymers is reported as electrodes for energy storage or conversion. Polyaniline and polypyrrole are effectively doped with electroactive polyoxometalates ([PMo12O40]3- or ferricyanide ([(FeCN6]3- anions as the only doping species. The high charge and size of these anions prevents their deintercalation during reduction in most cases. The synthesis of these hybrids can be made by chemical (bulk powders and electrochemical (films methods. For [PMo12O40]3-, nine aniline/pyrrole rings by anion are found in each case and the anion stays in the polymer matrix even after reduction at -0.4V (vs Ag/AgCl, 2.6V vs Li. In the case of Polypyrrole-FeCN6 hybrid the pyrrole-ring/Fe(CN6 ratio was around 10-12 depending on the temperature of synthesis. Temperature also affects the electrical conductivity, with the best values around 60Scm-1 (sample prepared at 0ºC. Fe(CN6 stays in the polymer matrix when the hybrid material is reduced in organic media. PMo12 hybrids intercalate up to 5.3 h+ during discharge (52 Ah/Kg whereas the hybrid with Fe(CN6 intercalates 2.7 lithium ions per formula unit (69Ah/Kg.

    Se describe la síntesis y aplicación como electrodos para el almacenamiento o conversión de energía de materiales híbridos basados en la dispersión de especies inorgánicas electroactivas en el seno de polímeros orgánicos conductores. Polianilina y polipirrol son dopados con polioxometalatos electroactivos ([PMo12O40]3- o aniones ferricianuro ([(FeCN6]3- como únicas especies dopantes. La elevada carga y tamaño de estos aniones evitan, en la mayoría de los casos, su desintercalación durante la reducción. Estos híbridos se han sintetizado por métodos químicos y electroquímicos, siendo la relación anillos de anilina o de pirrol por anión de [PMo12O40]3- de nueve, de manera que el anión permanece en el interior de la matriz

  12. Numerical simulation of H2S and CO2 generation during SAGD

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Perez, A.; Kamp, A.M. [CHLOE, UFR Science, University of Pau, 64000, Pau (France); Soleimani, H. (IFP School (France)); Darche, G. (TOTAL, Pau (France))

    2011-07-01

    In the heavy oil industry, the steam assisted gravity drainage process is often used to enhance oil recovery but the production of undesirable gases occurs during this process. These gases are mainly hydrogen sulphide and carbon dioxide, generated through chemical reactions triggered by high temperatures and water presence. The aim of this paper is to create a kinetic model for H2S and CO2 generation and to insert it in a reservoir simulation. This model was then tested under steam injection conditions in an SAGD system using experimental data available in the literature. The model developed successfully reproduced gas plateaus at different temperatures and results from the test showed that the model's predicted gas emissions are of the same order of magnitude as the field results. This paper presented a new kinetic model which can predict H2S and CO2 emissions of a SAGD system and could thus be used in the design of treatment facilities.

  13. H2-H2O-HI Hydrogen Separation in H2-H2O-HI Gaseous Mixture Using the Silica Membrane

    International Nuclear Information System (INIS)

    Pandiangan, Tumpal

    2002-01-01

    It was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical lS process. Porous alumina tube having pore size of 0.1 μm was modified by chemical vapor deposition using tetraethoxysilane. The permeance single gas of He, H 2 , and N 2 was measured at 300-600 o C. Hydrogen permeance of the modified membrane at a permeation temperature of 600 o C was about 5.22 x 10 -08 mol/Pa m 2 s, and 3.2 x 10 -09 of using gas mixture of H 2 -H 2 O-HI, where as HI permeances was below 1 x 10 -10 mol/Pa m 2 s. The Hydrogen permeance relative was not changed after 25 hours exposure in a mixture of H 2 -H 2 O-HI gas at the temperature of 450 o C. (author)

  14. Capped CuInS2 quantum dots for H2 evolution from water under visible light illumination

    International Nuclear Information System (INIS)

    Li, Tzung-Luen; Cai, Cheng-Da; Yeh, Te-Fu; Teng, Hsisheng

    2013-01-01

    Highlights: ► Dispersed CuInS 2 quantum dots showed remarkable photosynthetic activity using visible light. ► Photogenerated electrons in CuInS 2 were effective in H 2 production from aqueous solution. ► The bifunctional capping reagent effectively transported photogenerated electrons for reaction. ► Ru-loaded CuInS 2 quantum dots showed a quantum efficiency of 4.7% in H 2 evolution. ► Attaching CuInS 2 to TiO 2 with CdS passivation achieved a quantum efficiency of 41%. - Abstract: This study demonstrates H 2 evolution from water decomposition catalyzed by capped CuInS 2 quantum dots (QDs) that are highly dispersed in a polysulfide aqueous solution. The CuInS 2 QDs, which are obtained from solvothermal synthesis, have a size of 4.3 nm and a band gap of 1.97 eV. For photosynthetic H 2 evolution in the aqueous solution, the QDs are capped with a multidentate ligand (3-mercaptopropionic acid), which has a thiol end for attaching the QDs and a hydrophilic carboxylic end for dispersion in water. The capped QDs exhibit low activity in catalyzing H 2 evolution under visible illumination. After photodepositing 0.5 wt.% Ru, the capped QDs are active in producing H 2 with illumination. This demonstrates that the photogenerated electrons travel through the capping reagent to generate deposited Ru, which subsequently serves as an electron trap for H 2 evolution. A heterostructure formed by attaching the capped QDs on TiO 2 nanoparticles, followed by coating CdS with photodeposition, exhibits a high quantum efficiency of 41% for H 2 evolution from the polysulfide solution. These results demonstrate the potential for photosynthesis and phototherapy in biologic in vivo or microfluidic systems based on this capped QD material.

  15. Catalytic promiscuity and heme-dependent redox regulation of H2S synthesis.

    Science.gov (United States)

    Banerjee, Ruma

    2017-04-01

    The view of enzymes as punctilious catalysts has been shifting as examples of their promiscuous behavior increase. However, unlike a number of cases where the physiological relevance of breached substrate specificity is questionable, the very synthesis of H 2 S relies on substrate and reaction promiscuity, which presents the enzymes with a multitude of substrate and reaction choices. The transsulfuration pathway, a major source of H 2 S, is inherently substrate-ambiguous. A heme-regulated switch embedded in the first enzyme in the pathway can help avert the stochastic production of cysteine versus H 2 S and control switching between metabolic tracks to meet cellular needs. This review discusses the dominant role of enzyme promiscuity in pathways that double as sulfur catabolic and H 2 S synthetic tracks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

  17. Reactive pulsed laser deposition of Cu2ZnSnS4 thin films in H2S

    International Nuclear Information System (INIS)

    Surgina, G.D.; Zenkevich, A.V.; Sipaylo, I.P.; Nevolin, V.N.; Drube, W.; Teterin, P.E.; Minnekaev, M.N.

    2013-01-01

    Cu 2 ZnSnS 4 (CZTS) thin films have been grown by reactive pulsed laser deposition in H 2 S atmosphere, combining the alternate ablation from the metallic (Cu) and alloyed (Zn x Sn) targets at room temperature. The morphological, structural and optical properties of as grown CZTS thin films with varying compositions as well as upon annealing in N 2 atmosphere are investigated by Rutherford backscattering spectrometry, X-ray diffraction, Raman spectroscopy and optical spectrophotometry. The chemical bonding in the “bulk” of the CZTS films is elucidated via hard X-ray photoemission spectroscopy measurements. The formation of the good quality stoichiometric polycrystalline CZTS films is demonstrated upon optimization of the growth parameters. - Highlights: ► The new method of Cu 2 ZnSnS 4 (CZTS) thin films growth in H 2 S was realized. ► CZTS films were grown by pulsed laser deposition from Cu and alloyed Zn–Sn targets. ► The effect of the processing parameters on the CZTS properties was investigated. ► The chemical bonding in the “bulk” of CZTS films was studied

  18. Decapado de un acero inoxidable austenítico mediante mezclas ecológicas basadas en H2O2 - H2SO4 - iones F-

    Directory of Open Access Journals (Sweden)

    Narváez, L.

    2013-04-01

    Full Text Available This study reports the pickling of 316L stainless steel using mixtures of hydrogen peroxide (H2O2, sulphuric acid (H2SO4 and fluoride ions as hydrofluoric acid (HF, sodium fluoride (NaF and potassium fluoride (KF. The decomposition of H2O2 in the mixtures was assessed at different temperatures 25 °C to 60 °C, with ferric ion contents from 0 to 40 g/l. According to the results obtained, were established the optimal condition pickling at 20 g/l of ferric ions, 25 °C and p-toluensulphonic acid as stabilizer of H2O2. The HF pickling mixture was the only capable to remove totally the oxide layer from the 316L stainless steel after 300 s. The fluoride salts pickling mixtures only remove partially the oxide layer (20 to 40 % aprox. after 300 s. When the pickling time was increased until 1200 s, the removal percentages were around to 80 %.En este estudio se presenta el decapado del acero inoxidable austenítico 316L utilizando mezclas de peróxido de hidrógeno (H2O2/ácido sulfúrico (H2SO4/iones fluoruro; los iones fluoruro provienen del ácido fluorhídrico (HF, fluoruro de sodio (NaF y fluoruro de potasio (KF. La estabilidad del H2O2 fue valorada modificando las concentraciones del ión férrico de 0 a 40 g/l y las temperaturas de 25 °C a 60 °C en las mezclas decapantes. Se establecieron las condiciones óptimas de decapado utilizando 20 g/l de iones férrico a 25 °C empleando el ácido p-toluensulfónico como estabilizante del H2O2. La mezcla que contenía HF fue la única capaz de eliminar completamente los óxidos superficiales del acero a tiempos de 300 s. Las mezclas a base de sales fluoradas eliminaron parcialmente los óxidos (20 y 40 % aprox. en 300 s. Al incrementar el tiempo de decapado hasta 1200 s se obtuvieron porcentajes de eliminación alrededor de un 80 %.

  19. Electro-Chemical Behavior of Low Carbon Steel Under H2S Influence

    Science.gov (United States)

    Zaharia, M. G.; Stanciu, S.; Cimpoesu, R.; Nejneru, C.; Savin, C.; Manole, V.; Cimpoeșu, N.

    2017-06-01

    Abstract A commercial low carbon steel material (P265GH) with application at industrial scale for natural gas delivery and transportation systems was analyzed in H2S atmosphere. The article proposed a new experimental cell in order to establish the behavior of the material in sulfur contaminated environment. In most of the industrial processes for gas purification the corrosion rate is speed up by the presence of S (sulfur) especially as ions or species like H2S. The H2S (hydrogen sulfide) is, beside a very toxic compound, a very active element in the acceleration of metallic materials deterioration especially in complex solicitations like pressure and temperature in the same time. For experiments we used a three electrodes cell with Na2SO4 + Na2S solution at pH 3 at room temperature (∼ 25 °C) to realize EIS (electrochemical impedance spectroscopy) and potentio-dynamic polarization experiments. Scanning electron microscopy and X-ray dispersive energy spectroscopy were used to characterize the metallic material surface exposed to experimental environment.

  20. Generation of deposits and self ignited fires in H2S-H2O services (Paper No. 4.6)

    International Nuclear Information System (INIS)

    Agarwal, A.K.; Hiremath, S.C.

    1992-01-01

    The Heavy Water Plant (Kota) uses a large inventory of H 2 S gas at a nominal pressure and temperature. The plant has used mild steels/carbon steels as the material of construction of vessels, piping, flanges and fasteners. The entire construction is with flanged joints with raised face and spiral wound gaskets. Any leakages from any of the pipe line, flanged joints, heat exchanger covers, valve bonnets, valve glands etc causes H 2 S and H 2 O to leak out which generate deposits around the leakage paths after reaction with mild steel/carbon steels. The deposits grow into hard material, cause corrosion and thinning of stud bolts and gasket outer rings, weaken the confidence in the joint, and also cause ignited fires as they provide a source of ignition under certain conditions. (author). 2 refs

  1. DFT study of adsorption and dissociation behavior of H2S on Fe-doped graphene

    International Nuclear Information System (INIS)

    Zhang, Hong-ping; Luo, Xue-gang; Song, Hong-tao; Lin, Xiao-yan; Lu, Xiong; Tang, Youhong

    2014-01-01

    Highlights: • Fe-doped and Pt-doped graphene can significantly improve the interactions between H 2 S and graphene. • The location of S had an important role in the interactions between H 2 S and Fe-doped graphene. • The influence of Fe-S distance can be very weak in a certain range and H 2 S can be dissociated into S and H 2 . - Abstracts: Understanding the interaction mechanisms of hydrogen sulfide (H 2 S) with graphene is important in developing graphene-based sensors for gas detection and removal. In this study, the effects of doped Fe atom on interaction of H 2 S with graphene were investigated by density functional theory calculations. Analyses of adsorption energy, electron density difference, and density of states indicated that the doped Fe atom can significantly improve the interaction of H 2 S gas molecules with graphene, as well as Pt-doped graphene. The location of the sulfur atom is important in the interactions between H 2 S and Fe-doped graphene. The influence of the Fe-S distance can be very weak within a certain distance, as simulated in this study

  2. Effect of Water Content on Properties of Homogeneous [bmim]Fe(IIICl4–H2O Mixtures and Their Application in Oxidative Absorption of H2S

    Directory of Open Access Journals (Sweden)

    Jianhong Wang

    2018-01-01

    Full Text Available The potential of 1-butyl-3-methylimidazolium tetrachloroferrate ([bmim]Fe(IIICl4 for replacing an iron(III chelate catalytic solution in the catalytic oxidation of H2S is attributed to its no side reaction and no degradation of the chelating agent. The catalytic oxidation product of water in non-aqueous [bmim]Fe(IIICl4 possibly has an influence on the oxidative absorption of H2S. Water and hydrophobic [bmim]Fe(IIICl4 mixtures at water volume percents from 40% to 70% formed separate phases after srirring, without affecting the oxidative absorption of hydrogen sulfide. Then, studies on the properties of homogeneous [bmim]Fe(IIICl4–H2O mixtures at water volume percents in the range of 5.88–30% and above 80% reveal that these mixtures are both Brønsted and Lewis acids at vol % (H2O ≤ 30%, and only Lewis acids at vol % (H2O ≥ 80%. Raman spectra showed that [bmim]Fe(IIICl4 was the dominating species at vol % (H2O ≤ 30%, in contrast, [bmim]Fe(IIICl4 decomposed into FeCl3·2H2O and [bmim]Cl at vol % (H2O ≥ 80%. Further research on oxidative absorption of H2S by homogeneous [bmim]Fe(IIICl4–H2O mixtures demonstrated that [bmim]Fe(IIICl4 was reduced by H2S to [bmim]Fe(IICl4H and FeCl3·2H2O was reduced to FeCl2, at the same time, H2S was oxidized to S8. In addition, the decrease in acidity caused by increasing the water content increased the weight percent of absorbed H2S, and decreased volatile HCl emissions. However, it is difficult to prevent the suspended S8 generated at vol % (H2O ≥ 80% from the formation of sulfur blockage. Therefore, oxidative absorption of H2S by [bmim]Fe(IIICl4–H2O mixtures is feasible at vol % (H2O < 80% without sulfur blockage.

  3. Adsorption and dissociation of H{sub 2}S on Mo{sub 2}C(001) surface-A first-principle study

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Dianling; Guo, Wenyue, E-mail: wyguo@upc.edu.cn; Liu, Yunjie; Chi, Yuhua

    2015-10-01

    Highlights: • Adsorption of reactants, intermediates involved was investigated. • The Mulliken charge and partial density of states were analyzed. • The dissociation mechanism was investigated. • The optimal pathway for the dissociation of H{sub 2}S on the Mo{sub 2}C(001) surface was given. - Abstract: The adsorption and decomposition reaction mechanisms of H{sub 2}S on Mo{sub 2}C(001) has been systematically studied using self-consistent periodic density functional theory. Results show that the molecular of H{sub 2}S is adsorbed either on the Mo top site or bridge site. Mulliken population analysis and density of states for H{sub 2}S/Mo-terminated Mo{sub 2}C(001) adsorption system are examined to confirm the adsorption mechanism of H{sub 2}S with the Mo{sub 2}C(001) surface, which can involve the donation of charge from the “s lone pair electrons” that are LUMO orbitals into the surface and the back donation of electrons from the surface into the HOMO orbital. The optimal pathway for the dissociation of H{sub 2}S on the Mo{sub 2}C(001) surface can be H{sub 2}S{sub top} → SH{sub fcc} + H{sub fcc} → S{sub fcc} + H{sub fcc} + H{sub fcc}. The first step is the rate-determining step because it has the smallest rate constant among the possible reactions pathways.

  4. H(2s) excitation in 10-100 keV H+ - H collisions

    International Nuclear Information System (INIS)

    Higgins, D.P.; Geddes, J.; Gilbody, H.B.

    1996-01-01

    The authors have used a crossed beam technique to determine cross sections for 2s excitation of H atoms in 10-100 keV collisions. The results extend their previous 4-26 keV measurements to intermediate energies where theoretical predictions based on close coupling methods are known to be strongly dependent on the choice of the expansion basis. The 4-100 keV cross sections exhibit an undulatory structure similar to that predicted by some of the many close coupling calculations but good quantitative agreement is shown to be very limited. Close coupling calculations which employ large basis sets at the expense of target states are shown to agree less satisfactorily with experiment than those which include only the dominant 1s capture channel

  5. Plasmas pour valorisation totale ou partielle des gaz contenant de l'H2S Plasmas for Total Or Partial Upgrading of H2s Containing Gases

    Directory of Open Access Journals (Sweden)

    Czernichowski A.

    2006-12-01

    Full Text Available Des procédés par plasmas alternatifs au procédé Claus sont proposés pour produire de l'hydrogène et récupérer du soufre à partir des gaz contenant une forte teneur en H2S. Quand la teneur en H2S est moins importante, des techniques plasma peuvent également être utiles pour assister certains étages du procédé classique Claus ou réaliser ce procédé pour des gaz non conventionnels. Les tests allant jusqu'à l'échelle industrielle sont menés dans divers réacteurs à plasmas et les résultats encourageants rapportés de la littérature et de la recherche propre laissent envisager des prochaines applications. Plasma assisted processes are proposed to act as an alternative to the Claus process in order to recover hydrogen and sulphur from high H2S gases. For less concentrated gases plasma techniques may also be inserted into classical Claus plant or may allow treatment of non conventional gases. Up to industrial scale tests are performed using different plasma reactors. The literature-based results as well as our own ones make the future applications quite optimistic.

  6. Exogenous H2S facilitating ubiquitin aggregates clearance via autophagy attenuates type 2 diabetes-induced cardiomyopathy

    Science.gov (United States)

    Wu, Jichao; Tian, Zhiliang; Sun, Yu; Lu, Cuicui; Liu, Ning; Gao, Zhaopeng; Zhang, Linxue; Dong, Shiyun; Yang, Fan; Zhong, Xin; Xu, Changqing; Lu, Fanghao; Zhang, Weihua

    2017-01-01

    Diabetic cardiomyopathy (DCM) is a serious complication of diabetes. Hydrogen sulphide (H2S), a newly found gaseous signalling molecule, has an important role in many regulatory functions. The purpose of this study is to investigate the effects of exogenous H2S on autophagy and its possible mechanism in DCM induced by type II diabetes (T2DCM). In this study, we found that sodium hydrosulphide (NaHS) attenuated the augment in left ventricular (LV) mass and increased LV volume, decreased reactive oxygen species (ROS) production and ameliorated H2S production in the hearts of db/db mice. NaHS facilitated autophagosome content degradation, reduced the expression of P62 (a known substrate of autophagy) and increased the expression of microtubule-associated protein 1 light chain 3 II. It also increased the expression of autophagy-related protein 7 (ATG7) and Beclin1 in db/db mouse hearts. NaHS increased the expression of Kelch-like ECH-associated protein 1 (Keap-1) and reduced the ubiquitylation level in the hearts of db/db mice. 1,4-Dithiothreitol, an inhibitor of disulphide bonds, increased the ubiquitylation level of Keap-1, suppressed the expression of Keap-1 and abolished the effects of NaHS on ubiquitin aggregate clearance and ROS production in H9C2 cells treated with high glucose and palmitate. Overall, we concluded that exogenous H2S promoted ubiquitin aggregate clearance via autophagy, which might exert its antioxidative effect in db/db mouse myocardia. Moreover, exogenous H2S increased Keap-1 expression by suppressing its ubiquitylation, which might have an important role in ubiquitin aggregate clearance via autophagy. Our findings provide new insight into the mechanisms responsible for the antioxidative effects of H2S in the context of T2DCM. PMID:28796243

  7. Response speed of SnO2-based H2S gas sensors with CuO nanoparticles

    International Nuclear Information System (INIS)

    Chowdhuri, Arijit; Gupta, Vinay; Sreenivas, K.; Kumar, Rajeev; Mozumdar, Subho; Patanjali, P. K.

    2004-01-01

    CuO nanoparticles on sputtered SnO 2 thin-film surface exhibit a fast response speed (14 s) and recovery time (61 s) for trace level (20 ppm) H 2 S gas detection. The sensitivity of the sensor (S∼2.06x10 3 ) is noted to be high at a low operating temperature of 130 deg. C. CuO nanoparticles on SnO 2 allow effective removal of excess adsorbed oxygen from the uncovered SnO 2 surface due to spillover of hydrogen dissociated from the H 2 S-CuO interaction

  8. Synthesis of CdS nanorod arrays and their applications in flexible piezo-driven active H2S sensors

    International Nuclear Information System (INIS)

    Wang, Penglei; Deng, Ping; Nie, Yuxin; Zhao, Yayu; Xing, Lili; Xue, Xinyu; Zhang, Yan

    2014-01-01

    A flexible piezo-driven active H 2 S sensor has been fabricated from CdS nanorod arrays. By coupling the piezoelectric and gas sensing properties of CdS nanorods, the piezoelectric output generated by CdS nanorod arrays acts not only as a power source, but also as a response signal to H 2 S. Under externally applied compressive force, the piezoelectric output of CdS nanorod arrays is very sensitive to H 2 S. Upon exposure to 600 ppm H 2 S, the piezoelectric output of the device decreased from 0.32 V (in air) to 0.12 V. Such a flexible device can be driven by the tiny mechanical energy in our living environment, such as human finger pinching. Our research can stimulate a research trend on designing new material systems and device structures for high-performance piezo-driven active gas sensors. (paper)

  9. Advanced oxidation technology for H2S odor gas using non-thermal plasma

    Science.gov (United States)

    Tao, ZHU; Ruonan, WANG; Wenjing, BIAN; Yang, CHEN; Weidong, JING

    2018-05-01

    Non-thermal plasma technology is a new type of odor treatment processing. We deal with H2S from waste gas emission using non-thermal plasma generated by dielectric barrier discharge. On the basis of two criteria, removal efficiency and absolute removal amount, we deeply investigate the changes in electrical parameters and process parameters, and the reaction process of the influence of ozone on H2S gas removal. The experimental results show that H2S removal efficiency is proportional to the voltage, frequency, power, residence time and energy efficiency, while it is inversely proportional to the initial concentration of H2S gas, and ozone concentration. This study lays the foundations of non-thermal plasma technology for further commercial application.

  10. Breakdown of the Graphene Coating Effect under Sequential Exposure to O2 and H2S

    DEFF Research Database (Denmark)

    Nilsson, Louis; Andersen, Mie; Hammer, Bjørk

    2013-01-01

    exposures of O2 and H2S, a sequential dose of O2 and H2S causes a breakdown of the coating effect. From density functional theory calculations we explain these observations at the atomic level. We show that it is favorable for oxygen atoms to disrupt the Pt–C bonds at the graphene edge to insert between...... the edge and the surface in a bridging position. This closed-edge configuration explains why oxygen alone is not found to intercalate under the graphene at room temperature. With the subsequent dosing of H2S, we propose that the oxygen atoms are released from the platinum surface causing the breakdown...

  11. Thermodynamic properties of hydrated cement phases: C-S-H, C-A-S-H and M-S-H

    International Nuclear Information System (INIS)

    Roosz, Cedric

    2016-01-01

    representative phases of the studied chemical system, and (ii) a precise knowledge of the structure and chemical formulas of these phases. Three types of hydrates were therefore synthesized and characterized: C-S-H, C-A-S-H and M-S-H. Analytical methods such as XRD, TGA and solid state NMR ( 29 Si, 27 Al) are used to ascertain similarities between the structure of C-(A-)S-H and that of tobermorite, and between the structure of M-S-H and that of Mg-Si phyllosilicates 2:1. Hydrates, however, have a lower crystallinity, with defects in the polymerization of silica chains, and random stacking faults (turbostratism). A multi-technique approach is also used, combining adsorption isotherm(water and nitrogen) and 1 HNMR with XRD and TGA, and allows characterization of different types of water more or less bound to the structure of C-(A-)S-H. This study allowed to highlight and quantify the different types of water in the C-(A-)S-H structure. The impact of the drying process was also highlighted on the quantification of different types of water, including interlayer water. The acquisition of thermodynamic parameters of the synthesized phases is carried out from the analysis of equilibrium solutions for the calculation of log K and Δ f G 0 , while calorimetric acquisitions permit obtaining heat capacities and the calculation of S 0 . Finally, enthalpy of formation of these phases is calculated from the Gibbs free energy of formation and entropies. The predictive model is developed from the acquired thermodynamic properties. The Gibbs free energy of formation Δ f G 0 is predicted from an electronegativity model, while Cp and S 0 are predicted through polyhedral decomposition model. Finally, a comparison of data obtained with those published in the literature, and the realization of predominance diagrams generalized to the whole CaO-MgO-Al 2 O 3 -SiO 2 -H 2 O system assess the reliability of the proposed model. (author) [fr

  12. Pt-decorated graphene as superior media for H2S adsorption: A first-principles study

    International Nuclear Information System (INIS)

    Ganji, Masoud Darvish; Sharifi, Narges; Ardjmand, Mahdi; Ahangari, Morteza Ghorbanzadeh

    2012-01-01

    Highlights: ► We report the first DFT study in the H 2 S/Pt–graphene system. ► The adsorption properties of H 2 S at different possible site on the surface of pristine graphene are slightly stable presenting energies from 0.02 to 0.06 eV. ► When Pt decorates the graphene sheet on the single and double sides the H 2 S adsorption energy increase to −3.2 eV. ► A single Pt atom can locate up to seven H 2 S molecules stably binded with energies from −6.73 to −0.95 eV. ► The DOS plot indicates strong hybridization between H 2 S molecules and Pt–graphene sheet. - Abstract: The adsorption mechanism of hydrogen sulfide (H 2 S) molecules on pristine and Pt-decorated graphene sheets was studied using density functional theory calculations based on local density approximation and generalized gradient approximation methods. Our calculations show that a Pt-decorated graphene system has much higher binding energy, higher net charge transfer values and shorter connecting distances than pristine graphene due to chemisorption of the H 2 S molecule. Furthermore, the calculated density of states show that orbital hybridization is visible between the H 2 S and Pt-decorated graphene sheets, while there is no evidence for hybridization between the H 2 S molecule and the pristine graphene sheet. Interestingly, we find that up to seven H 2 S molecules can stably bind to a Pt atom on each side of the graphene sheet with desirable binding energy.

  13. Internal defect propagation studies in carbon steel in H2S-H2O system (Pre print No. MI-1C)

    International Nuclear Information System (INIS)

    Dalvi, M.S.; Kini, R.A.; Tangri, V.K.; Sadhukhan, H.K.

    1989-04-01

    Carbon steel is the material of construction for major equipment of heavy water plant using H 2 S-H 2 O exchange process for production of heavy water. The main corrosion product in this system is iron sulphide and hydrogen which is liberated in nascent form. It is known that such hydrogen liberated in-situ in the equipment has tendency to penetrate in the metal, giving rise to phenomena of embrittlement. Similarly, if parent metal has internal defect then this nascent hydrogen gets trapped in them and gets converted to diatomic form and consequent rise in pressure. This leads to the spread of the defect and can lead to severe loss in the strength of metal. This phenomena was studied on the walls of an autoclave used in a corrosion test assembly for simulated investigation of material of construction for H 2 S-H O exchange process. These studies indicate that internal defect propagation and generation definitely takes place in the system. However, no failures were encountered. These studies have been very qualitative in nature but showed the importance of this aspect of corrosion in H 2 S-H 2 O system and is a subject matter for further studies. It also implies that intial testing of plates for internal defects is very important. (author). 3 figs

  14. A breakthrough in flue gas cleanup, CO2 mitigation and H2S removal

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Wolf; Wasas, James; Stenger, Raymond; Howell, Evan

    2010-09-15

    SWAPSOL Corp. is developing commercial processes around a newly discovered reaction that reduces H2S below detectable levels while reacting with CO2 to form water, sulfur and carsuls, a carbon-sulfur polymer. The Stenger-Wasas Process (SWAP) stands to simplify sulfur removal technology as it consumes CO2 in an exothermic reaction. The SWAP has applications in landfill, sour, flue and Claus tail gas cleanup and may replace Claus technology. Destruction of waste hydrocarbons provides a source of H2S. The primary reactions and variants have been independently verified and the chemical kinetics determined by a third party laboratory.

  15. Preparation of polyaniline/PbS core-shell nano/microcomposite and its application for photocatalytic H2 electrogeneration from H2O.

    Science.gov (United States)

    Rabia, Mohamed; Mohamed, H S H; Shaban, Mohamed; Taha, S

    2018-01-18

    Lead sulfide (PbS) and polyaniline (PANI) nano/microparticles were prepared. Then, PANI/PbS core-shell nano/microcomposites (I, II, and III) were prepared by oxidative polymerization of different aniline concentrations (0.01, 0.03, and 0.05 M), respectively, in the presence of 0.05 M PbS. FT-IR, XRD, SEM, HR-TEM, and UV-Vis analyses were carried out to characterize the samples. From the FT-IR data, there are redshifts in PbS and PANI nano/microparticles bands in comparison with PANI/PbS nano/microcomposites. The average crystallite sizes of PANI/PbS core-shell nano/microcomposites (I, II, and III) from XRD analyses were 46.5, 55, and 42.16 nm, respectively. From the optical analyses, nano/microcomposite (II) has the optimum optical properties with two band gaps values of 1.41 and 2.79 eV. Then, the nano/microcomposite (II) membrane electrode supported on ITO glass was prepared and applied on the photoelectrochemical (PEC) H 2 generation from H 2 O. The characteristics current-voltage and current-time behaviors were measured at different wavelengths from 390 to 636 nm. Also, the incident photon-to-current conversion efficiency (IPCE) under monochromatic illumination condition was calculated. The optimum values for IPCE were 36.5 and 35.2% at 390 and 405 nm, respectively. Finally, a simple mechanism for PEC H 2 generation from H 2 O using the nano/microcomposite (II) membrane electrode was mentioned.

  16. The rational design of a peptide-based hydrogel responsive to H2S.

    Science.gov (United States)

    Peltier, Raoul; Chen, Ganchao; Lei, Haipeng; Zhang, Mei; Gao, Liqian; Lee, Su Seong; Wang, Zuankai; Sun, Hongyan

    2015-12-18

    The development of hydrogels that are responsive to external stimuli in a well-controlled manner is important for numerous biomedical applications. Herein we reported the first example of a hydrogel responsive to hydrogen sulphide (H2S). H2S is an important gasotransmitter whose deregulation has been associated with a number of pathological conditions. Our hydrogel design is based on the functionalization of an ultrashort hydrogelating peptide sequence with an azidobenzyl moiety, which was reported to react with H2S selectively under physiological conditions. The resulting peptide was able to produce hydrogels at a concentration as low as 0.1 wt%. It could then be fully degraded in the presence of excess H2S. We envision that the novel hydrogel developed in this study may provide useful tools for biomedical research.

  17. Synthesis and structure of PbBipy2(1-B10H9S(CH3)2)2

    International Nuclear Information System (INIS)

    Orlova, A.M.; Sivaev, I.B.; Lagun, V.L.; Katser, S.B.; Solntsev, K.A.; Kuznetsov, N.T.

    1993-01-01

    Lead complex with B 10 H 9 S(CH 3 ) 2 - anion and 2,2'-bipyridine was synthesized and characterized. According to the data of X-ray diffraction analysis the crystals belong to monoclinic crystal system, sp. gr. P2 1 /a: a = 9.940(4), b 31.568(4), c = 13.458(2) A, β = 111.09(2) deg, V = 3940(2) A 3 , Z = 4. The structure consists of monomer units PbBipy 2 (1-B 10 H 9 S(CH 3 ) 2 ) 2 . The Pb-B distances are within 3.24-3.55 A. 15 refs., 1 fig., 2 tabs

  18. Specific IgE to peanut 2S albumin Ara h 7 has a discriminative ability comparable to Ara h 2 and 6

    NARCIS (Netherlands)

    Blankestijn, Mark A; Otten, Henry G.; Suer, Waltraud; Weimann, Alf; Knol, Edward F; Knulst, André C

    BACKGROUND: Little is known on the clinical relevance of peanut 2S albumin Ara h 7. OBJECTIVE: To investigate the discriminative ability of Ara h 7 in peanut allergy and assess the role of cross-reactivity between Ara h 2, 6 and Ara h 7 isoforms. METHODS: Sensitization to recombinant peanut storage

  19. Production of H,D(2s, 2p) by electron impact (0 - 2000 eV) on simple hydrogen containing molecules, ch. 2, A2

    International Nuclear Information System (INIS)

    Moehlman, G.R.; Heer, F.J. de

    1977-01-01

    Absolute emission cross sections of Ly-α (H,D(2p → 1s)) radiation have been determined for 0 - 2000 eV electrons incident on H 2 , HD, HCl, H 2 O, NH 3 and CH 4 . By means of the application of electric quenching, the excitation cross sections of H,D(2s) could be obtained from the increase of the resulting Ly-α radiation for these molecules. Only in the case of electrons on H 2 , D 2 and HD was excitation of H,D(2s) found

  20. Synthesis and Characterisation of Tris(1-carboxyl-2-phenyl-1,2-ethyl eno dithiol enic-S,S') Tungsten Complex as Photo catalyst for Photolysis of H2O Molecules

    International Nuclear Information System (INIS)

    Fadhli Hadana Rahman; Rusli Daik; Mohammad Kassim; Khuzaimah; Wan Ramli Wan Daud

    2008-01-01

    Tris(1-carboxyl-2-phenyl-1,2-ethylenodithiolenic-S,S ' ) tungsten complex is one of the most promising photo catalyst to be used in photolysis of water to produce hydrogen. The first step of the synthesis involves a metathesis reaction of tetrapropylammonium bromide [((C 3 H 7 ) 4 N)Br] and ammonium tetrathiotungstate [(NH 4 ) 2 WS 4 ] to form a tetrapropylammonium tetrathiotungstate [((C 3 H 7 ) 4 N) 2 WS 4 ] (precursor). Then, the precursor was reacted with phenyl acetylenecarboxylic acid (C 9 H 6 O 2 ) to form tris(1-carboxyl-2-phenyl-1,2-ethylenodithiolenic-S,S ' ) tungsten complex (C 27 H 18 O 2 S 6 W). The infra-red, ultra violet/ visible (UV/ Vis) spectrum, nuclear magnetic resonance (NMR) and elemental micro-analysis of C, H, N and S agreed with the characteristic of the tris(1-carboxyl-2-phenyl-1,2-ethylenodithiolenic-S,S ' ) tungsten complex. The (W-S), (C-S) and (C=O) stretching frequencies were detected at 511, (1470 and 1035) and 1655 cm -1 , respectively. The 1 H NMR spectrum showed six protons in the complex. The 13 C NMR showed only 7 signals for carbon atom in the benzene ring, ethylene groups and carboxylic acid pendant group due to the symmetry of the molecules. The reaction yield was about 50 percent. Photolysis of acetone spiked H 2 O showed that the catalyst was able to produced 1.8 μmol/ h hydrogen. (author)

  1. H S Maiti

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. H S Maiti. Articles written in Bulletin of Materials Science. Volume 24 Issue 2 April 2001 pp 197-201. Mechanical properties of glass polymer multilayer composite · A Seal N R Bose S K Dalui A K Mukhopadhyay K K Phani H S Maiti · More Details Abstract Fulltext PDF.

  2. Corrosion of electronic devices of the electronics industry of Mexicali, B.C. México influenced by H2S pollution

    Directory of Open Access Journals (Sweden)

    Gustavo López Badilla

    2012-01-01

    Full Text Available El sulfuro de hidrógeno (H2S es un ácido débil que se dispersa en el aire, por el viento cuando se emite a partir de fuentes naturales y antropogénicas, principalmente de las plantas industriales. Es un contaminante con un alto nivel de toxicidad que afecta a la calidad del medio ambiente. Es un contaminante atmosférico agresivo que ataca los metales utilizados en la industria electrónica como acero al carbono, cobre y aleaciones de plata, y formación de películas delgadas como productos de corrosión y dendritas, siendo los sulfuros los más comunes que dañan las superficies metálicas, promoviendo la corrosión metálica. Este gas ingresa a los interiores de las plantas industriales, por los sistemas de aire acondicionado, agujeros, techos, en cualquier período del año. En las temporadas de otoño, invierno y primavera, el personal en las empresas deja algunas puertas abiertas en ciertas áreas de las empresas, por no tener sistemas de aire acondicionado, con el conocimiento del efecto negativo del H2S en los componentes metálicos de componentes electrónicos, y este ácido corrosivo penetra fácilmente. Por esta razón, se realizó un estudio en el interior de dos plantas de la industria electrónica en Mexicali expuestos a bajas concentraciones de H2S, para determinar el daño causado a estos dispositivos electrónicos. Se aplicó la técnica de Microscopía Electrónica de Barrido (MBE para determinar los tipo de tipos de corrosión formados: uniforme o picaduras principalmente, y conocer con mayor exactitud los agentes químicos que reaccionan con las superficies metálicas de los componentes electrónicos. La técnica MBE muestra las microfotografías y la información de los productos de corrosión presentados en este estudio, en correlación con la humedad relativa (HR y los niveles de temperatura.

  3. Electrochemical H2O2 biosensor composed of myoglobin on MoS2 nanoparticle-graphene oxide hybrid structure.

    Science.gov (United States)

    Yoon, Jinho; Lee, Taek; Bapurao G, Bharate; Jo, Jinhee; Oh, Byung-Keun; Choi, Jeong-Woo

    2017-07-15

    In this research, the electrochemical biosensor composed of myoglobin (Mb) on molybdenum disulfide nanoparticles (MoS 2 NP) encapsulated with graphene oxide (GO) was fabricated for the detection of hydrogen peroxide (H 2 O 2 ). Hybrid structure composed of MoS 2 NP and GO (GO@MoS 2 ) was fabricated for the first time to enhance the electrochemical signal of the biosensor. As a sensing material, Mb was introduced to fabricate the biosensor for H 2 O 2 detection. Formation and immobilization of GO@MoS 2 was confirmed by transmission electron microscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and scanning tunneling microscopy. Immobilization of Mb, and electrochemical property of biosensor were investigated by cyclic voltammetry and amperometric i-t measurements. Fabricated biosensor showed the electrochemical signal enhanced redox current as -1.86μA at an oxidation potential and 1.95μA at a reduction potential that were enhanced relative to those of electrode prepared without GO@MoS 2 . Also, this biosensor showed the reproducibility of electrochemical signal, and retained the property until 9 days from fabrication. Upon addition of H 2 O 2 , the biosensor showed enhanced amperometric response current with selectivity relative to that of the biosensor prepared without GO@MoS 2 . This novel hybrid material-based biosensor can suggest a milestone in the development of a highly sensitive detecting platform for biosensor fabrication with highly sensitive detection of target molecules other than H 2 O 2 . Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Xu, T.; Li, Y.

    2010-12-15

    The geological storage of CO{sub 2} in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, costs of capture and compression of CO{sub 2} from industrial waste streams containing small quantities of sulfur and nitrogen compounds such as SO{sub 2}, H{sub 2}S and N{sub 2} are very expensive. Therefore, studies on the co-injection of CO{sub 2} containing other acid gases from industrial emissions are very important. In this paper, numerical simulations were performed to study the co-injection of H{sub 2}S with CO{sub 2} in sandstone and carbonate formations. Results indicate that the preferential dissolution of H{sub 2}S gas (compared with CO{sub 2} gas) into formation water results in the delayed breakthrough of H{sub 2}S gas. Co-injection of H{sub 2}S results in the precipitation of pyrite through interactions between the dissolved H{sub 2}S and Fe{sup 2+} from the dissolution of Fe-bearing minerals. Additional injection of H{sub 2}S reduces the capabilities for solubility and mineral trappings of CO{sub 2} compared to the CO{sub 2} only case. In comparison to the sandstone (siliciclastic) formation, the carbonate formation is less favorable to the mineral sequestration of CO{sub 2}. Different from CO{sub 2} mineral trapping, the presence of Fe-bearing siliciclastic and/or carbonate is more favorable to the H{sub 2}S mineral trapping.

  5. Surface Defect Passivation and Reaction of c-Si in H2S.

    Science.gov (United States)

    Liu, Hsiang-Yu; Das, Ujjwal K; Birkmire, Robert W

    2017-12-26

    A unique passivation process of Si surface dangling bonds through reaction with hydrogen sulfide (H 2 S) is demonstrated in this paper. A high-level passivation quality with an effective minority carrier lifetime (τ eff ) of >2000 μs corresponding to a surface recombination velocity of passivation by monolayer coverage of S on the Si surface. However, S passivation of the Si surface is highly unstable because of thermodynamically favorable reaction with atmospheric H 2 O and O 2 . This instability can be eliminated by capping the S-passivated Si surface with a protective thin film such as low-temperature-deposited amorphous silicon nitride.

  6. Behaviour of ceramic and metallic layers in a H2O-H2S

    International Nuclear Information System (INIS)

    Furtuna, I.; Mihailescu, M.; Deaconu, M.; Dinu, A.; Cotolan, V; Nedelcu, L.; Titescu, Gh.

    1996-01-01

    In the installations for heavy water production there exist zones where the action of aggressive working conditions combined with a severe variable hydrodynamical regime lead to the destruction of the pyrite protecting layer. An alternating solution for the protection of these zones is to cover them with ceramic or metallic layers. This work presents the results of the preliminary tests on G28-52 steel samples, covered with ceramic and metallic layers, in the working environment (H 2 O-H 2 S) of the heavy water production installations and in severe hydrodynamical conditions. On the basis of the results obtained in the experiments and from the examination of the microstructure of the layers prior and after testing, a phenomenological model was developed to explain the behaviour of the deposed layers. On the basis of this model the conditions that the layers must satisfy have been deduced to improve their behaviour in the working environment

  7. Exogenous hydrogen sulfide (H2S protects alveolar growth in experimental O2-induced neonatal lung injury.

    Directory of Open Access Journals (Sweden)

    Arul Vadivel

    Full Text Available Bronchopulmonary dysplasia (BPD, the chronic lung disease of prematurity, remains a major health problem. BPD is characterized by impaired alveolar development and complicated by pulmonary hypertension (PHT. Currently there is no specific treatment for BPD. Hydrogen sulfide (H2S, carbon monoxide and nitric oxide (NO, belong to a class of endogenously synthesized gaseous molecules referred to as gasotransmitters. While inhaled NO is already used for the treatment of neonatal PHT and currently tested for the prevention of BPD, H2S has until recently been regarded exclusively as a toxic gas. Recent evidence suggests that endogenous H2S exerts beneficial biological effects, including cytoprotection and vasodilatation. We hypothesized that H2S preserves normal alveolar development and prevents PHT in experimental BPD.We took advantage of a recently described slow-releasing H2S donor, GYY4137 (morpholin-4-ium-4-methoxyphenyl(morpholino phosphinodithioate to study its lung protective potential in vitro and in vivo.In vitro, GYY4137 promoted capillary-like network formation, viability and reduced reactive oxygen species in hyperoxia-exposed human pulmonary artery endothelial cells. GYY4137 also protected mitochondrial function in alveolar epithelial cells. In vivo, GYY4137 preserved and restored normal alveolar growth in rat pups exposed from birth for 2 weeks to hyperoxia. GYY4137 also attenuated PHT as determined by improved pulmonary arterial acceleration time on echo-Doppler, pulmonary artery remodeling and right ventricular hypertrophy. GYY4137 also prevented pulmonary artery smooth muscle cell proliferation.H2S protects from impaired alveolar growth and PHT in experimental O2-induced lung injury. H2S warrants further investigation as a new therapeutic target for alveolar damage and PHT.

  8. Variability of O2, H2S, and pH in intertidal sediments measured on a highly resolved spatial and temporal scale

    Science.gov (United States)

    Walpersdorf, E.; Werner, U.; Bird, P.; de Beer, D.

    2003-04-01

    We investigated the variability of O_2, pH, and H_2S in intertidal sediments to assess the time- and spatial scales of changes in environmental conditions and their effects on bacterial activities. Measurements were performed over the tidal cycle and at different seasons by the use of microsensors attached to an autonomous in-situ measuring device. This study was carried out at a sand- and a mixed flat in the backbarrier area of Spiekeroog (Germany) within the frame of the DFG research group "Biogeochemistry of the Wadden Sea". Results showed that O_2 variability was not pronounced in the coastal mixed flat, where only extreme weather conditions could increase O_2 penetration. In contrast, strong dynamics in O_2 availability, pH and maximum penetration depths of several cm were found at the sandflat. In these highly permeable sediments, we directly observed tidal pumping: at high tide O_2-rich water was forced into the plate and at low tide anoxic porewater drained off the sediment. From the lower part of the plate where organic rich clayey layers were embedded in the sediment anoxic water containing H_2S leaked out during low tide. Thus advective processes, driven by the tidal pump, waves and currents, control O_2 penetration and depth distribution of H_2S and pH. The effects of the resulting porewater exchange on mineralization rates and microbial activities will be discussed.

  9. Reducción de la biomasa del pino carrasco ("Pinus Halepensis") en un área del sureste semiárido peninsular como estrategia para evitar el estrés hídrico

    OpenAIRE

    Belmonte Serrato, Francisco; López Bermúdez, Francisco; Romero Díaz, María Asunción

    2008-01-01

    En las épocas de fuertes sequías, la vegetación mediterránea sufre un estado de estrés hídrico prolongado que le obliga a adoptar diversas estrategias de supervivencia, entre las que fi guran, como último recurso, y antes de llegar a superar su capacidad de resilencia, la reducción de la biomasa de hojas. En este trabajo se pone de manifi esto como algunos ejemplares de Pinus halepensis existentes en el área de estudio (el campo experimental de El Ardal, Murcia), redujeron apreciablemente su ...

  10. High-temperature removal of H2S from syngas by means of zinc-contaminated soils

    International Nuclear Information System (INIS)

    Tzu-Hsing Ko; Hsin-Ta Hsueh

    2006-01-01

    Hydrogen sulfide (H 2 S) is one of the most common compounds and can be easily found in advanced power generation plants, such as integrated gasification combined cycle (IGCC) and molten-carbonate fuel cell (MCFC) plants. Generally, in these systems raw materials with high heating value (HHV) or biomass were gasified under high temperature and produced a useful mixture gas. During the gasification, hydrogen sulfide accompanies with a great quantity of reductive gases at high temperature including CO, H 2 , CH 4 and N 2 , etc. This mixture gas is so-call syngas. Syngas is a valuable resource for electric power generation. Prior to using, H 2 S needs to be removed because its harmful effect. In addition, H 2 S is not only the malodorous and corrosive gas but also is the sources of the acid rain when it is oxidized into SO 2 and reacted with water. It has been known for many years that certain soils have the ability to absorb reductive sulfur-containing species such as hydrogen sulfide (H 2 S), carbonyl sulfide (COS), carbon disulfide (CS 2 ), dimethyl sulfide (CH 3 SCH 3 ) and dimethyl disulfide (CH 3 SSCH 3 ) at room temperature. Therefore, soils could act as an important sorption media for the removal of waste gases before they are released into the atmosphere. In this study, we further use the contaminated soils as regenerable sorbent for the removal of H 2 S from syngas under high temperature. Results indicate that contaminated soils could be used to remove H 2 S as well as maintain at least 90% regeneration efficiency after regeneration cycles. Additionally, zinc and iron appeared to be the major active species to react with H 2 S. The chemical structure of zinc and iron after removal of H 2 S could be expressed as ZnS and FeS. In addition to removal of H 2 S, it is also established that contaminated soil can be used for application which reduce the problem of heavy metal contaminated soils (Full text of contribution)

  11. Synthesis of new dithiacobaltaborane clusters derived from arachno-6,8-S2B7H9

    International Nuclear Information System (INIS)

    Kang, S.O.; Sneddon, L.G.

    1988-01-01

    A series of air-stable dithiacobaltaborane clusters has been isolated from either the reaction of the arachno-S 2 B 7 H 8 - anion with cobalt chloride and pentamethylcyclopentadienide or the reaction of neutral arachno-6,8-S 2 B 7 H 9 with cobalt atoms and pentamethylcyclopentadiene. Thus, the reaction of arachno-S 2 B 7 H 8 - with CoCl 2 and C 5 (CH 3 ) 5 - in THF gave, as the major products, the triple-decker compound nido-4,6-η-C 5 (CH 3 ) 52 Co 2 -3,5-S 2 B 2 H 2 (I) and the 11-vertex cluster nido-8,10(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (III). Also isolated in smaller amounts were a chloride derivative of I, nido-1-Cl-4,6-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -3,5-S 2 B 2 H (II), two isomers of III, nido-3,10-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (IV) and nido-3,5-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (V), and the eight-boron cluster nido-8-(η-C 5 (CH 3 ) 5 )Co-7,9-S 2 B 8 H 8 (VI). Other trace products of the reaction included the six-boron clusters nido-5,8-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -6,9-S 2 B 6 H 6 (VII) and arachno-7-(η-C 5 (CH 3 ) 5 )Co-6,8-S 2 B 6 H 8 (VIII). Compound III was found to isomerize at 250 degree C to IV, which could then be converted to V at 300 degree C. The reaction of cobalt atoms with arachno-6,8-S 2 B 7 H 9 in the presence of pentamethylcyclopentadiene gave VIII as the major product; however, a number of other clusters including I, V, VI, and [(η-C 5 (CH 3 ) 5 ) 2 Co] + [(SB 10 H 10 ) 2 Co] - were isolated in trace amounts. 16 references, 6 figures, 3 tables

  12. Effect of H2S exposure on S-35-sulfate uptake, transport and utilization in curly kale

    NARCIS (Netherlands)

    Westerman, S; Weidner, W; De Kok, LJ; Stulen, I.

    2000-01-01

    When Brassica oleracea L. was exposed to 0.2 mul l(-1) H2S the sulfate uptake measured during a dark or light period was decreased to the same extent. Both the xylem loading and the net sulfate uptake rate were decreased by 42% after 6 days of exposure to 0.4 mul l(-1) H2S. This suggested that the

  13. Nervios corneales prominentes como manifestación inicial en el síndrome de neoplasia endocrina múltiple tipo 2B

    Directory of Open Access Journals (Sweden)

    Vianney Cortés-González

    2015-10-01

    Conclusiones: La identificación de las características oculares, tanto los nervios corneales como los neuromas palpebrales, puede ayudar a un diagnóstico temprano del síndrome MEN2B. El oftalmólogo debe identificar las características oftalmológicas de la enfermedad y diferenciarlas de otras afecciones como las distrofias corneales. Los nervios corneales prominentes consisten en numerosos axones desmielinizados y múltiples células de Schwann.

  14. Surface type conversion of CuInSe2 with H2S plasma exposure: A photoemission investigation

    International Nuclear Information System (INIS)

    Nelson, A.J.; Frigo, S.P.; Rosenberg, R.

    1995-01-01

    Surface type conversion of CuInSe 2 by H 2 S plasma exposure was studied by synchrotron radiation soft x-ray photoemission spectroscopy. The low power H 2 S plasma was generated with a commercial electron cyclotron resonance plasma source using pure H 2 S with the plasma exposure being performed at 400 degree C. In situ photoemission measurements were acquired after each plasma exposure in order to observe changes in the valence band electronic structure as well as changes in the In 4d and Se 3d core lines. The results were correlated in order to relate changes in surface chemistry to the electronic structure. These measurements indicate that the H 2 S plasma exposure type converts the n-type CuInSe 2 surface to a p-type surface at this elevated temperature and that the magnitude of the band bending is 0.5 eV, resulting in a homojunction interface. copyright 1995 American Vacuum Society

  15. Production of H, D (2s, 2p) by electron impact (0-2000 eV) on simple hydrogen containing molecules

    International Nuclear Information System (INIS)

    Moehlmann, G.R.; Shima, K.H.; Heer, F.J. de

    1978-01-01

    Absolute emission cross sections of Ly-α (H, D (2p → 1s)) radiation have been determined for 0-2000 eV electrons incident on H 2 , HD, D 2 , HCl, H 2 O, NH 3 and CH 4 . By means of the application of electric quenching the excitation cross sections of H, D (2s) could be obtained from the increase of the resulting Ly-α radiation for these molecules. It was found that only for H 2 , HD and D 2 fragments in the H (2s) state are formed. (Auth.)

  16. Fate of H2S during the cultivation of Chlorella sp. deployed for biogas upgrading.

    Science.gov (United States)

    González-Sánchez, Armando; Posten, Clemens

    2017-04-15

    The H 2 S may play a key role in the sulfur cycle among the biogas production by the anaerobic digestion of wastes and the biogas upgrading by a microalgae based technology. The biogas is upgraded by contacting with slightly alkaline aqueous microalgae culture, then CO 2 and H 2 S are absorbed. The dissolved H 2 S could limit or inhibit the microalgae growth. This paper evaluated the role of dissolved H 2 S and other sulfured byproducts under prevailing biogas upgrading conditions using a microalgal technology. At initial stages of batch cultivation the growth of Chlorella sp. was presumably inhibited by dissolved H 2 S. After 2 days, the sulfides were oxidized mainly by oxic chemical reactions to sulfate, which was later rapidly assimilated by Chlorella sp., allowing high growing rates. The fate of H 2 S during the microalgae cultivation at pH > 8.5 was assessed by a mathematical model where the pentasulfide, thiosulfate and sulfite were firstly produced and converted finally to sulfate for posterior assimilation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Bare nucleus S(E) factor of the 2H(d,p)3H and 2H(d,n)3He reactions via the Trojan Horse Method

    International Nuclear Information System (INIS)

    Tumino, A; Spitaleri, C; Kiss, G G; Cognata, M La; Lamia, L; Pizzone, R G; Rapisarda, G G; Romano, S; Sergi, M L; Spartà, R; Mukhamedzhanov, A M; Typel, S; Aliotta, M; Burjan, V; Kroha, V; Hons, Z; Mrazek, J; Piskor, S; Santo, M Gimenez del

    2012-01-01

    The Trojan Horse Method was applied for the first time to the 2 H(d,p) 3 H and 2 H(d,n) 3 He reactions by measuring the 2 H( 3 He,p 3 H) 1 H and 2 H( 3 He,n 3 He) 1 H processes in quasi free kinematics. The 3 He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4±1.8 MeVb for 3 H+p and 60.1±1.9 MeVb for 3 He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

  18. FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H2S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS

    International Nuclear Information System (INIS)

    Chen, Y.-J.; Juang, K.-J.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S.; Nuevo, M.; Jiménez-Escobar, A.; Muñoz Caro, G. M.; Wu, C.-Y. R.; Fung, H.-S.; Ip, W.-H.

    2015-01-01

    Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H 2 S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H 2 S and CO 2 :H 2 S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS 2 , OCS, SO 2 , etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H 2 S ice mixtures is higher than that of CO 2 :H 2 S ice mixtures; (2) a lower concentration of H 2 S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS 2 differ significantly upon VUV and EUV irradiations. Furthermore, CS 2 was produced only after VUV photoprocessing of CO:H 2 S ices, while the VUV-induced production of SO 2 occurred only in CO 2 :H 2 S ice mixtures. More generally, the production yields of OCS, H 2 S 2 , and CS 2 were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H 2 S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments

  19. [Determination of H2S in Rat Intestinal Perfusion Solution Based on Fluorescence Analysis].

    Science.gov (United States)

    Hou, Jun-feng; Li, Xin-xia; Shen, Xue-ru; Huojia, Miliban; Guan, Ming

    2015-08-01

    Under alkaline conditions, Fluorescein mercury has strong fluorescence, however, when it met S(2-), its fluorescence would quench, in view of the above, a fluorescence method for determination of H2S in biological samples was established. In the 0.1 mol · L(-1) NaOH dilution, when the concentration of fluorescein Mercury and Na2S was 5.0 × 10(-5) and 1.0 × 10(-5) mol · L(-1) respectively, the fluorescence intensity of system was determined at 522 nm. The results showed that, at the range of 4.0 × 10(-7)~2.0 × 10(-6) mol · L(-1), the concentration decreasing of H2S and fluorescence intensity had good linear relationship, r=0.9980, the RSD of precision test was 4.59% (n=7), the detection limit was 3.5 × 10(-8) mol · L(-1), the content of H2S in the sample were 1.01 × 10(-6) and 1.15 × 10(-6) mol · L(-1), and the recovery rate was 95.8%~101.0%, the method has the advantages of simple operation, high sensitivity, good selectivity, can accurately determine of H2S in intestinal perfused solution, and provides the basis for the determination of endogenous H2S.

  20. Direct Z-scheme TiO2/CdS hierarchical photocatalyst for enhanced photocatalytic H2-production activity

    Science.gov (United States)

    Meng, Aiyun; Zhu, Bicheng; Zhong, Bo; Zhang, Liuyang; Cheng, Bei

    2017-11-01

    Photocatalytic H2 evolution, which utilizes solar energy via water splitting, is a promising route to deal with concerns about energy and environment. Herein, a direct Z-scheme TiO2/CdS binary hierarchical photocatalyst was fabricated via a successive ionic layer adsorption and reaction (SILAR) technique, and photocatalytic H2 production was measured afterwards. The as-prepared TiO2/CdS hybrid photocatalyst exhibited noticeably promoted photocatalytic H2-production activity of 51.4 μmol h-1. The enhancement of photocatalytic activity was ascribed to the hierarchical structure, as well as the efficient charge separation and migration from TiO2 nanosheets to CdS nanoparticles (NPs) at their tight contact interfaces. Moreover, the direct Z-scheme photocatalytic reaction mechanism was demonstrated to elucidate the improved photocatalytic performance of TiO2/CdS composite photocatalyst. The photoluminescence (PL) analysis of hydroxyl radicals were conducted to provide clues for the direct Z-scheme mechanism. This work provides a facile route for the construction of redox mediator-free Z-scheme photocatalytic system for photocatalytic water splitting.

  1. S H Aravind

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. S H Aravind. Articles written in Resonance – Journal of Science Education. Volume 2 Issue 6 June 1997 pp 89-90 Think It Over. To Find Four Distinct Positive Integers such that the Sum of Any Two of them is a Square · S H Aravind · More Details Fulltext PDF ...

  2. H2S-Mediated Thermal and Photochemical Methane Activation

    NARCIS (Netherlands)

    Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric V.

    2013-01-01

    Sustainable, low-temperature methods for natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) mixed with

  3. Trapping {BW12}2 tungstoborate: synthesis and crystal structure of hybrid [{(H2BW12O42)2O}{Mo6O6S6(OH)4(H2O)2}]14- anion.

    Science.gov (United States)

    Korenev, V S; Abramov, P A; Vicent, C; Mainichev, D A; Floquet, S; Cadot, E; Sokolov, M N; Fedin, V P

    2012-12-28

    Reaction between monolacunary {BW(11)} tungstoborate and oxothiocationic building block, {Mo(2)O(2)S(2)}, results in the formation of a new polyoxothiometalate with a unique architecture in which two [H(2)BW(12)O(43)](9-) tungstoborate subunits are linked together with a hexamolybdate [Mo(V)(6)O(6)S(6)(OH)(4)(H(2)O)(2)](2+) bridge.

  4. Hybridized 1T/2H MoS2 Having Controlled 1T Concentrations and its use in Supercapacitors.

    Science.gov (United States)

    Thi Xuyen, Nguyen; Ting, Jyh-Ming

    2017-12-06

    Molybdenum disulfide (MoS 2 ) nanoflowers consisting of hybridized 1T/2H phases have been synthesized by using a microwave-assisted hydrothermal (MTH) method. The concentration of the 1T phase, ranging from 40 % to 73 %, is controlled by simply adjusting the ratio of the Mo and S precursors. By using the hybridized 1T/2H MoS 2 as an electrode material, it was demonstrated that the resulting supercapacitor performance is dominated by the 1T phase concentration. It was found that a supercapacitor with 73 % 1T phase exhibits excellent capacitance of 259 F g -1 and great cyclic stability after 1000 cycles. The formation mechanism of the MHT-synthesized hybridized 1T/2H MoS 2 is also reported. More importantly, the mechanism also explains the observed relationship between the 1T phase concentration and the ratio of the Mo and S precursors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. An H2S Sensor Based on Electrochemistry for Chicken Coops

    Science.gov (United States)

    Zeng, Lihua; He, Mei; Yu, Huihui; Li, Daoliang

    2016-01-01

    The recent modernization of the livestock industry lags behind the scale of the livestock industry, particularly in indoor environmental monitoring. In particular, the H2S gas concentration in chicken coops affects the growth and reproductive capacity of the chickens and threatens their health. Therefore, the research and development of a low-cost, environmentally friendly sensor that can achieve on-line monitoring of H2S gas has a notably important practical significance. This paper reports the design of an H2S gas sensor, with selection of an electrochemical probe with high accuracy and wide measurement range using the relatively mature technology of electrochemical sensors. Although the probe of the sensor is the main factor that affects the sensor accuracy, the probe must be combined with a specifically designed signal condition circuit that can overcome the lack of an electrode to satisfy the requirements for the interconnection and matching between the output signal and the test instrument. Because the output current of the electrochemical electrode is small and likely to be disturbed by noise, we designed signal-conditioning modules. Through the signal-conditioning circuit, the output signal of the current electrode can be converted into a voltage and amplified. In addition, we designed a power control module because a bias voltage is necessary for the electrode. Finally, after the calibration experiment, the accurate concentration of H2S gas can be measured. Based on the experimental analysis, the sensor shows good linearity and selectivity, comparatively high sensitivity, perfect stability and an extremely long operating life of up to two years. PMID:27589757

  6. Mineral storage of CO2/H2S gas mixture injection in basaltic rocks

    Science.gov (United States)

    Clark, D. E.; Gunnarsson, I.; Aradottir, E. S.; Oelkers, E. H.; Sigfússon, B.; Snæbjörnsdottír, S. Ó.; Matter, J. M.; Stute, M.; Júlíusson, B. M.; Gíslason, S. R.

    2017-12-01

    Carbon capture and storage is one solution to reducing CO2 emissions in the atmosphere. The long-term geological storage of buoyant supercritical CO2 requires high integrity cap rock. Some of the risk associated with CO2 buoyancy can be overcome by dissolving CO2 into water during its injection, thus eliminating its buoyancy. This enables injection into fractured rocks, such as basaltic rocks along oceanic ridges and on continents. Basaltic rocks are rich in divalent cations, Ca2+, Mg2+ and Fe2+, which react with CO2 dissolved in water to form stable carbonate minerals. This possibility has been successfully tested as a part of the CarbFix CO2storage pilot project at the Hellisheiði geothermal power plant in Iceland, where they have shown mineralization occurs in less than two years [1, 2]. Reykjavik Energy and the CarbFix group has been injecting a mixture of CO2 and H2S at 750 m depth and 240-250°C since June 2014; by 1 January 2016, 6290 tons of CO2 and 3530 tons of H2S had been injected. Once in the geothermal reservoir, the heat exchange and sufficient dissolution of the host rock neutralizes the gas-charged water and saturates the formation water respecting carbonate and sulfur minerals. A thermally stable inert tracer was also mixed into the stream to monitor the subsurface transport and to assess the degree of subsurface carbonation and sulfide precipitation [3]. Water and gas samples have been continuously collected from three monitoring wells and geochemically analyzed. Based on the results, mineral saturation stages have been defined. These results and tracer mass balance calculations are used to evaluate the rate and magnitude of CO2 and H2S mineralization in the subsurface, with indications that mineralization of carbon and sulfur occurs within months. [1] Gunnsarsson, I., et al. (2017). Rapid and cost-effective capture and subsurface mineral storage of carbon and sulfur. Manuscript submitted for publication. [2] Matter, J., et al. (2016). Rapid

  7. H2S adsorption and decomposition on the gradually reduced α-Fe2O3(001) surface: A DFT study

    Science.gov (United States)

    Lin, Changfeng; Qin, Wu; Dong, Changqing

    2016-11-01

    Reduction of iron based desulfurizer occurs during hot gas desulfurization process, which will affect the interaction between H2S and the desulfurizer surface. In this work, a detailed adsorption behavior and dissociation mechanism of H2S on the perfect and reduced α-Fe2O3(001) surfaces, as well as the correlation between the interaction characteristic and reduction degree of iron oxide, have been studied by using periodic density functional theory (DFT) calculations. Results demonstrate that H2S firstly chemisorbs on surface at relatively higher oxidation state (reduction degree χ 33%. Reduction of iron oxide benefits the H2S adsorption. Further, dissociation processes of H2S via molecular and dissociative adsorption were investigated. Results show that after reduction of Fe2O3 into the oxidation state around FeO and Fe, the reduced surface exhibits very strong catalytic capacity for H2S decomposition into S species. Meanwhile, the overall dissociation process on all surfaces is exothermic. These results provide a fundamental understanding of reduction effect of iron oxide on the interaction mechanism between H2S and desulfurizer surface, and indicate that rational control of reduction degree of desulfurizer is essential for optimizing the hot gas desulfurization process.

  8. Thermodynamic model for the phase equilibria of gases and brines. Example in the H{sub 2}S-H{sub 2}O-NaCl system

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Reyes, Jose; Gonzalez Partida, Eduardo; Tinoco-Michel, Jorge A [Centro de Geociencias, Universidad Nacional Autonoma de Mexico Campo de Juriquilla, Qro., Mexico, apartado postal 76230 (Mexico); Perez, Renee J; Heidemann, Robert A [Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive, Calgary Alberta, T2N 1N4 (Canada)

    2008-10-01

    We present a thermodynamic model for the phase equilibria of gases and brines, which couples Henry's Law with the Soave-Redlich-Kwong equation of state to reproduce experimental data. In this communication we focus on the H{sub 2}S H{sub 2}O NaCl system.

  9. Synthesis of Copper Sulfide Nanoparticles Using Biogenic H2S Produced by a Low-pH Sulfidogenic Bioreactor

    Directory of Open Access Journals (Sweden)

    Camila Colipai

    2018-01-01

    Full Text Available The application of acidophilic sulfate-reducing bacteria (SRB for the treatment of acidic mine water has been recently developed to integrate mine water remediation and selective biomineralization. The use of biogenic hydrogen sulfide (H2S produced from the dissimilatory reduction of sulfate to fabricate valuable products such as metallic sulfide nanoparticles has potential applications in green chemistry. Here we report on the operation of a low-pH sulfidogenic bioreactor, inoculated with an anaerobic sediment obtained from an acid river in northern Chile, to recover copper via the production of copper sulfide nanoparticles using biogenic H2S. The laboratory-scale system was operated as a continuous flow mode for up to 100 days and the bioreactor pH was maintained by the automatic addition of a pH 2.2 influent liquor to compensate for protons consumed by biosulfidogenesis. The “clean” copper sulfide nanoparticles, produced in a two-step process using bacterially generated sulfide, were examined using transmission electron microscopy, dynamic light scattering, energy dispersive (X-ray spectroscopy and UV-Vis spectroscopy. The results demonstrated a uniform nanoparticle size distribution with an average diameter of less than 50 nm. Overall, we demonstrated the production of biogenic H2S using a system designed for the treatment of acid mine water that holds potential for large-scale abiotic synthesis of copper sulfide nanoparticles.

  10. A new approach to recovery of H2S from gaseous waste streams (Paper No. 6.4)

    International Nuclear Information System (INIS)

    Jain, M.P.; Kini, R.A.; Dalvi, M.S.; Tangri, V.K.; Sadhukhan, H.K.

    1992-01-01

    Heavy water production plants based on H 2 S-H 2 O exchange process employs a large quantity of H 2 S as carrier gas. Considerable amount of H 2 S is lost during maintenance and operation of the plant. Detailed studies have been made to assess the suitability of adsorbing H 2 S from a mixture of gases through molecular sieves of 13x type. (author). 2 figs

  11. Photolysis of low concentration H2S under UV/VUV irradiation emitted from microwave discharge electrodeless lamps.

    Science.gov (United States)

    Xia, Lan-Yan; Gu, Ding-Hong; Tan, Jing; Dong, Wen-Bo; Hou, Hui-Qi

    2008-04-01

    The photolysis of simulating low concentration of hydrogen sulfide malodorous gas was studied under UV irradiation emitted by self-made microwave discharge electrodeless lamps (i.e. microwave UV electrodeless mercury lamp (185/253.7 nm) and iodine lamp (178.3/180.1/183/184.4/187.6/206.2 nm)). Experiments results showed that the removal efficiency (eta H2S) of hydrogen sulfide was decreased with increasing initial H2S concentration and increased slightly with gas residence time; H2S removal efficiency was decreased dramatically with enlarged pipe diameter. Under the experimental conditions with pipe diameter of 36 mm, gas flow rate of 0.42 standard l s(-1), eta H2S was 52% with initial H2S concentration of 19.5 mg m(-3) by microwave mercury lamp, the absolute removal amount (ARA) was 4.30 microg s(-1), and energy yield (EY) was 77.3 mg kW h(-1); eta H2S was 56% with initial H2S concentration of 18.9 mg m(-3) by microwave iodine lamp, the ARA was 4.48 microg s(-1), and the EY was 80.5mg kW h(-1). The main photolysis product was confirmed to be SO4(2-) with IC.

  12. Aplicación de sustancias húmicas comerciales como productos de acción bioestimulante: efectos frente al estrés salino

    OpenAIRE

    Ramos Ruiz, Roberto

    2000-01-01

    El amplio desarrollo de la agricultura de régimen intensivo, con el consiguiente empleo de fertilizantes minerales de manera indiscriminada, se ha traducido en una pérdida de los niveles óptimos de materia orgánica del suelo. Por ello, y para restablecer dichos niveles, los agricultores han utilizado, en muchos casos, cantidades muy importantes de sustancias húmicas comerciales. Es decir, hasta ahora, las sustancias húmicas se han venido empleando mayoritariamente como mejoradores de la...

  13. Centrifugal turbocompressor with contactless sealing for H-2 S

    International Nuclear Information System (INIS)

    Peculea, M.; Balint, I.; Hirean, I.; Dumitrescu, C.; Pitigoi, Gh.; Balanuca, C.

    1995-01-01

    This paper reports the development of a centrifugal turbocompressor with contactless sealing for H 2 S specially designed for the ROMAG Drobeta heavy water plant. The bench-scale experiments are described and the resulted main characteristics are given. For this equipment an asymmetric automatic anti-pumping protection system has been developed and patented

  14. FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H{sub 2}S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.-J.; Juang, K.-J.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S. [Department of Physics, National Central University, Jhongli City, Taoyuan County 32054, Taiwan (China); Nuevo, M. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Jiménez-Escobar, A.; Muñoz Caro, G. M. [Centro de Astrobiología, INTA-CSIC, Torrejón de Ardoz, E-28850 Madrid (Spain); Wu, C.-Y. R. [Space Sciences Center and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-1341 (United States); Fung, H.-S. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Ip, W.-H. [Graduate Institute of Astronomy, National Central University, Jhongli City, Taoyuan County 32049, Taiwan (China)

    2015-01-10

    Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H{sub 2}S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H{sub 2}S and CO{sub 2}:H{sub 2}S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS{sub 2}, OCS, SO{sub 2}, etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H{sub 2}S ice mixtures is higher than that of CO{sub 2}:H{sub 2}S ice mixtures; (2) a lower concentration of H{sub 2}S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS{sub 2} differ significantly upon VUV and EUV irradiations. Furthermore, CS{sub 2} was produced only after VUV photoprocessing of CO:H{sub 2}S ices, while the VUV-induced production of SO{sub 2} occurred only in CO{sub 2}:H{sub 2}S ice mixtures. More generally, the production yields of OCS, H{sub 2}S{sub 2}, and CS{sub 2} were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H{sub 2}S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments.

  15. Hydrothermal growth of two dimensional hierarchical MoS2 nanospheres on one dimensional CdS nanorods for high performance and stable visible photocatalytic H2 evolution

    Science.gov (United States)

    Chava, Rama Krishna; Do, Jeong Yeon; Kang, Misook

    2018-03-01

    The visible photocatalytic H2 production from water splitting considered as a clean and renewable energy source could solve the problem of greenhouse gas emission from fossil fuels. Despite tremendous efforts, the development of cost effective, highly efficient and more stable visible photocatalysts for splitting of water remains a great challenge. Here, we report the heteronanostructures consisting of hierarchical MoS2 nanospheres grown on 1D CdS nanorods referred to as CdS-MoS2 HNSs as a high performance visible photocatalyst for H2 evolution. The as-synthesized CdS-MoS2 HNSs exhibited ∼11 fold increment of H2 evolution rate when compared to pure CdS nanorods. This remarkable enhanced hydrogen evolution performance can be assigned to the positive synergetic effect from heteronanostructures formed between the CdS and MoS2 components which assist as an electron sink and source for abundant active edge sites and in turn increases the charge separation. This study presents a low-cost visible photocatalyst for solar energy conversion to achieve efficient H2.

  16. A DFT study of SO2 and H2S gas adsorption on Au-doped single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Zhang, Xiaoxing; Dai, Ziqiang; Chen, Qinchuan; Tang, Ju

    2014-01-01

    Intrinsic carbon nanotubes (CNTs) show limited toxic gas detection, thus, we need to develop a method to fabricate a novel CNT sensor that has good sensitivity. In this study, density functional theory (DFT) was applied to determine the adsorption behavior of Au-doped single-walled carbon nanotubes (Au-SWCNTs) to SO 2 and H 2 S. The calculated results show that Au-SWCNTs have a high sensitivity to SO 2 and H 2 S. When SO 2 adsorbs on the surface of the nanotube, a large number of electrons transfer from the Au-SWCNT to SO 2 , which results in a decrease in the frontier orbital energy gap and an increase in electrical conductivity. On the other hand, when H 2 S adsorbs on the surface of the nanotube, the electrons transfer from H 2 S to the Au-SWCNT, the frontier orbital energy gap increases, and the electrical conductivity decreases. Thus, SO 2 and H 2 S could be detected by Au-SWCNTs. This conclusion is useful for the development of CNT-based gas sensors and provides a theoretical basis to fabricate Au-SWCNT-based gas sensors. (papers)

  17. [4,6-Dimethylpyrimidine-2(1H-thione-κS]iodidobis(triphenylphosphane-κPcopper(I

    Directory of Open Access Journals (Sweden)

    Chaveng Pakawatchai

    2012-06-01

    Full Text Available In the mononuclear title complex, [CuI(C6H8N2S(C18H15P2], the CuI ion is in a slightly distorted tetrahedral coordination geometry formed by two P atoms from two triphenylphosphane ligands, one S atom from a 4,6-dimethylpyrimidine-2(1H-thione ligand and one iodide ion. There is an intramolecular N—H...I hydrogen bond. In the crystal, π–π stacking interactions [centroid–centroid distance = 3.594 (1 Å] are observed.

  18. MESSAGE 2 space experiment with Rhodospirillum rubrum S1H

    Data.gov (United States)

    National Aeronautics and Space Administration — R. rubrum S1H inoculated on solid agar rich media was sent to the ISS in October 2003 (MESSAGE-part 2 experiment). After 10 days flight R. rubrum cultures returned...

  19. Online analysis of H2S and SO2 via advanced mid-infrared gas sensors.

    Science.gov (United States)

    Petruci, João Flavio da Silveira; Wilk, Andreas; Cardoso, Arnaldo Alves; Mizaikoff, Boris

    2015-10-06

    Volatile sulfur compounds (VSCs) are among the most prevalent emitted pollutants in urban and rural atmospheres. Mainly because of the versatility of sulfur regarding its oxidation state (2- to 6+), VSCs are present in a wide variety of redox-environments, concentration levels, and molar ratios. Among the VSCs, hydrogen sulfide and sulfur dioxide are considered most relevant and have simultaneously been detected within naturally and anthropogenically caused emission events (e.g., volcano emissions, food production and industries, coal pyrolysis, and various biological activities). Next to their presence as pollutants, changes within their molar ratio may also indicate natural anomalies. Prior to analysis, H2S- and SO2-containing samples are usually preconcentrated via solid sorbents and are then detected by gas chromatographic techniques. However, such analytical strategies may be of limited selectivity, and the dimensions and operation modalities of the involved instruments prevent routine field usage. In this contribution, we therefore describe an innovative portable mid-infrared chemical sensor for simultaneously determining and quantifying gaseous H2S and SO2 via coupling a substrate-integrated hollow waveguides (iHWG) serving as a highly miniaturized mid-infrared photon conduit and gas cell with a custom-made preconcentration tube and an in-line UV-converter device. Both species were collected onto a solid sorbent within the preconcentrator and then released by thermal desorption into the UV-device. Hydrogen sulfide is detected by UV-assisted quantitative conversion of the rather weak IR-absorber H2S into SO2, which provides a significantly more pronounced and distinctively detectable rovibrational signature. Modulation of the UV-device system (i.e., UV-lamp on/off) enables discriminating between SO2 generated from H2S conversion and abundant SO2 signals. After optimization of the operational parameters, calibrations in the range of 0.75-10 ppmv with a limit

  20. Photolysis of low concentration H2S under UV/VUV irradiation emitted from high frequency discharge electrodeless lamps.

    Science.gov (United States)

    Xu, Jianhui; Li, Chaolin; Liu, Peng; He, Di; Wang, Jianfeng; Zhang, Qian

    2014-08-01

    The photolysis of low concentration of H2S malodorous gas was studied under UV irradiation emitted by self-made high frequency discharge electrodeless lamp with atomic mercury lines at 185/253.7nm. Experiments results showed that the removal efficiency (ηH2S) of H2S was decreased with increasing initial H2S concentration and increased slightly with gas residence time. ηH2S was increased dramatically with relative humidity from<5% to 43% while the concentration of oxygen in gas environments affected the removal of H2S. The mechanisms for direct and indirect photolysis (generation of ozone) were illustrated by the experimental results on photolysis of H2S under argon environments and ozonation of H2S under air environments, respectively. The overall ηH2S by photolysis is higher than the combination of ηH2S by direct photolysis and ozonation, suggesting that hydroxyl radical-mediated indirect photolysis played an important role during photolysis processes. The main photolysis product was confirmed to be SO4(2-) with ion chromatograph. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Peak effect studies in single crystals CeRu2 and 2H-NbS2

    Indian Academy of Sciences (India)

    vibrating sample magnetometer (VSM) (Oxford Instruments, UK) on single crystal sam- ples of CeRu2 and 2H-NbS2. All the measurements were carried out by cooling the sample in zero field (ZFC mode) and then by applying the magnetic field. The measurements were carried out with the magnetic field parallel to the cube ...

  2. Synthesis and evaluation of (S)-4-(3-(2'-[C-11]isopropylamino)-2-hydroxy-propoxy)-2H-benzimidazol-2-one ((S)-[C-11]CGP 12388) and (S)-4-(3-((1'-[F-18]-fluoroisopropyl)amino)-2-hydroxypropoxy)-2H-benzimidazol-2-one ((S)-[F-18]Fluoro-CGP 12388) for visualization of beta-adrenoceptors with positron emission tomography

    NARCIS (Netherlands)

    Elsinga, PH; vanWaarde, A; Jaeggi, KA; Schreiber, G; Heldoorn, M; Vaalburg, W

    1997-01-01

    The beta-adrenoceptor antagonist (S)-[C-11]CGP 12177 (4-(3-(tert-butylamino)-2-hydroxypropoxy)- 2H-benzimidazol-2[C-11]-one) is a generally accepted radioligand for cardiac and pulmonary PET studies. The synthesis of [C-11]CGP 12177 is a laborious and often troublesome procedure. Therefore, (S)-C GP

  3. Measurements of quadrupolar interaction by perturbed angular correltion method on intercalated 2H-TaS sub(2)

    International Nuclear Information System (INIS)

    Saitovitch, H.

    1979-01-01

    This work is based on our quadrupolar interaction (QI) measurements on intercalated 2H-TaS sub(2) coumponds. As intercalating elements we used the alcalines - Li, Na, K, Cs -as well as the NH sub(3) (ammonia) and C sub(6) H sub(5) N (pyridine) molecules. The (QI) measurements were performed via the differential perturbed angular correlation (DPAC) technique, using Ta sup(181) as the probe isotope, on the hydrated and anhidrous phases of the intercalated systems. Our results happened to be in better agreement with the ionic model, one of the accepted models used to describe the intercalation process, as well as the transfered charges quantities and its distribution in the intercalated systems. And by its side the measured quantities, quadrupole interaction frequencies (QIF) and their distributions δ, contributed to support and to improve the ionic model. A strong charge dynamics between the 2H-TaS sub(2) sandwiches was observed and a relation between the (QIF) changes and amount of transfered charge (e sup(-)/Ta) was established. The attempt to specify the numerical contributions to the (QI) changes arriving from the different components of the 2H-TaS sub(2) intercalated systems put in evidence the probable orbitals involved in the systems bonds. Finally the kinetics of the intercalation process to form the 2H-TaS sub(2) (Li) sub(x) system was followed continuously by the (DPAC) measurements. (author)

  4. Orbital selectivity causing anisotropy and particle-hole asymmetry in the charge density wave gap of 2 H -TaS2

    Science.gov (United States)

    Zhao, J.; Wijayaratne, K.; Butler, A.; Yang, J.; Malliakas, C. D.; Chung, D. Y.; Louca, D.; Kanatzidis, M. G.; van Wezel, J.; Chatterjee, U.

    2017-09-01

    We report an in-depth angle-resolved photoemission spectroscopy study on 2 H -TaS2 , a canonical incommensurate charge density wave (CDW) system. This study demonstrates that just as in related incommensurate CDW systems, 2 H -TaSe2 and 2 H -NbSe2 , the energy gap (ΔCDW) of 2 H -TaS2 is localized along the K -centered Fermi surface barrels and is particle-hole asymmetric. The persistence of ΔCDW even at temperatures higher than the CDW transition temperature TCDW in 2 H -TaS2 , reflects the similar pseudogap behavior observed previously in 2 H -TaSe2 and 2 H -NbSe2 . However, in sharp contrast to 2 H -NbSe2 , where ΔCDW is nonzero only in the vicinity of a few "hot spots" on the inner K -centered Fermi surface barrels, ΔCDW in 2 H -TaS2 is nonzero along the entirety of both K -centered Fermi surface barrels. Based on a tight-binding model, we attribute this dichotomy in the momentum dependence and the Fermi surface specificity of ΔCDW between otherwise similar CDW compounds to the different orbital orientations of their electronic states that participate in the CDW pairing. Our results suggest that the orbital selectivity plays a critical role in the description of incommensurate CDW materials.

  5. The catalytic activity of Ag{sub 2}S-montmorillonites as peroxidase mimetic toward colorimetric detection of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingyun, E-mail: qyliu@sdust.edu.cn [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Jiang, Yanling; Zhang, Leyou; Zhou, Xinpei [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Lv, Xintian [School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000 (China); Ding, Yanyuan; Sun, Lifang; Chen, Pengpeng [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Yin, Hailiang [Academy of Science & Technology, China University of Petroleum, Dongying 257061 (China)

    2016-08-01

    Nanocomposites based on silver sulfide (Ag{sub 2}S) and Ca-montmorillonite (Ca{sup 2+}-MMT) were synthesized by a simple hydrothermal method. The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectra (FTIR). The as-prepared Ag{sub 2}S-MMT nanocomposites were firstly demonstrated to possess intrinsic peroxidase-like activity and could rapidly catalytically oxidize the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H{sub 2}O{sub 2} to produce a blue product which can be seen by the naked eye in only one minute. The experimental results revealed that the Ag{sub 2}S-MMT nanocomposites exhibit higher thermal durance. Based on the TMB–H{sub 2}O{sub 2} catalyzed color reaction, the Ag{sub 2}S-MMT nanocomposites were exploited as a new type of biosensor for detection and estimation of H{sub 2}O{sub 2} through a simple, cheap and selective colorimetric method. - Highlights: • Ag{sub 2}S – montmorillonites (MMT) was synthesized by a facile one step method. • The as-prepared Ag{sub 2}S-MMT nanocomposites firstly demonstrate to possess intrinsic peroxidase-like activity. • Ag{sub 2}S-MMT nanocomposites showed highly catalytic activity. • Ag{sub 2}S-MMT could rapidly catalytically oxidize substrates TMB in the presence of H{sub 2}O{sub 2} in 1 min. • The catalytic mechanism is from the generation of hydroxyl radical (·OH) decomposed from H{sub 2}O{sub 2}.

  6. Textural and mechanical characterization of C-S-H gels from hydration of synthetic T1-C3S, β-C2S and their blends

    International Nuclear Information System (INIS)

    Goni, S.; Guerrero, A.; Puertas, F.; Hernandez, M. S.; Palacios, M.; Dolado, J. S.; Zhu, W.; Howind, T.

    2011-01-01

    The textural and mechanical characterization of C-S-H gels formed from the hydration of pure T1-C 3 S, β-C 2 S and their blends are studied by Nitrogen sorption and nano indentation experiments. The surface area and nano porosity of C-S-H gels formed from the hydration of β-C 2 S and the 30-70 (T1-C 3 S and β-C 2 S mixture) are higher than those from hydration of T1-C 3 S, and 70-30, with the difference decreasing with hydration age. Such changes are well supported by findings of nano indentation study, which shows the greater relative volume of C-S-H phases with lower densities in the β-C 2 S and the 30-70 pastes. With the increase in hydration age, the relative volume of C-S-H phases with higher densities increased at the expenses of those with lower density. Important quantitative correlations were found among these textural characteristics and the mean chain length, determined from 2 9Si magic-angle-spinning (MAS) NMR, of the C-S-H gels. (Author) 36 refs.

  7. Quantum dynamics of the reaction H((2)S) + HeH(+)(X(1)Σ(+)) → H2(+)(X(2)Σg(+)) + He((1)S) from cold to hyperthermal energies: time-dependent wavepacket study and comparison with time-independent calculations.

    Science.gov (United States)

    Gamallo, Pablo; Akpinar, Sinan; Defazio, Paolo; Petrongolo, Carlo

    2014-08-21

    We present the adiabatic quantum dynamics of the proton-transfer reaction H((2)S) + HeH(+)(X(1)Σ(+)) → H2(+)(X(2)Σg(+)) + He((1)S) on the HeH2(+) X̃(2)Σ(+) RMRCI6 (M = 6) PES of C. N. Ramachandran et al. ( Chem. Phys. Lett. 2009, 469, 26). We consider the HeH(+) molecule in the ground vibrational–rotational state and obtain initial-state-resolved reaction probabilities and the ground-state cross section σ0 and rate constant k0 by propagating time-dependent, coupled-channel, real wavepackets (RWPs) and performing a flux analysis. Three different wavepackets are propagated to describe the wide range of energies explored, from cold (0.0001 meV) to hyperthermal (1000 meV) collision energies, and in a temperature range from 0.01 to 2000 K. We compare our time-dependent results with the time-independent ones by D. De Fazio and S. Bovino et al., where De Fazio carried out benchmark coupled-channel calculations whereas Bovino et al. employed the negative imaginary potential and the centrifugal-sudden approximations. The RWP cross section is in good agreement with that by De Fazio, except at the lowest collision energies below ∼0.01 meV, where the former is larger than the latter. However, neither the RWP and De Fazio results possess the huge resonance in probability and cross section at 0.01 meV, found by Bovino et al., who also obtained a too low σ0 at high energies. Therefore, the RWP and De Fazio rate constants compare quite well, whereas that by Bovino et al. is in general lower.

  8. C-A-S-H synthesis and thermodynamics modelling in CaO-Al2O3-SiO2-H2O system

    International Nuclear Information System (INIS)

    Haas, J.; Pochard, I.; Nonat, A.

    2015-01-01

    Ordinary Portland cement (OPC) is being increasingly replaced by blended cements, where part of the clinker is replaced by secondary cementitious materials (SCM) such as blast furnace or fly ash. The use of SCM enables to achieve various aims as the cost reduction by recovery of by-products, the CO 2 emission reduction, the obtaining of specific properties as low pH. So, blended cements are more and more current in different fields as civil engineering and nuclear waste repository. The use of silica and/or aluminium rich SCMs directly impacts the amount and the kind of hydrates formed, hence the volume and the porosity and finally the durability of these materials. Aluminates containing hydrates formation is not well understood. Al content can result from Al-uptake in C-S-H due to Al-substitution of Si-tetrahedra to well crystallised hydrates like straetlingite or katoite phases. This study proposes a surface dependant thermodynamic model to predict and to correlate the Al-uptake (substitution) of C-A-S-H with solutions representative of that of cement pores chemistry. For this purpose, pure C-A-S-H alkali-free were synthesized in diluted suspensions. On one hand, hydrates and their solutions were characterized at equilibrium. On the other hand, thermodynamics modelling were performed from these collected data to describe C-A-S-H in the equilibrium solutions. These results allowed evaluating the Al-availability in the cementitious system and especially for aluminates containing hydrates precipitation. (authors)

  9. Removal of H2S and volatile organic sulfur compounds by silicone membrane extraction

    NARCIS (Netherlands)

    Manconi, I.; Lens, P.N.L.

    2009-01-01

    BACKGROUND: This study explores an alternative process for the abatement and/or desulfurization of H2S and volatile organic sulfur compounds (VOSC) containing waste streams, which employs a silicone-based membrane to simultaneously remove H2S and VOSC. An extractive membrane reactor allows the

  10. Textural and mechanical characterization of C-S-H gels from hydration of synthetic T1-C3S, β-C2S and their blends

    Directory of Open Access Journals (Sweden)

    Dolado, J. S.

    2011-06-01

    Full Text Available The textural and mechanical characterization of C-S-H gels formed from the hydration of pure T1-C3S, β-C2S and their blends are studied by Nitrogen sorption and nanoindentation experiments. The surface area and nanoporosity of C-S-H gels formed from the hydration of β-C2S and the 30-70 (T1-C3S and β-C2S mixture are higher than those from hydration of T1-C3S, and 70-30, with the difference decreasing with hydration age. Such changes are well supported by findings of nanoindentation study, which shows the greater relative volume of C-S-H phases with lower densities in the β-C2S and the 30-70 pastes. With the increase in hydration age, the relative volume of C-S-H phases with higher densities increased at the expenses of those with lower density. Important quantitative correlations were found among these textural characteristics and the mean chain length, determined from 29Si magic-angle-spinning (MAS NMR, of the C-S-H gels.La caracterización textural y mecánica de geles C-S-H formados a partir de la hidratación de muestras puras de T1-C3S, ß-C2S y sus mezclas ha sido estudiada por medio de adsorción de nitrógeno y nanoindentación. El área superficial y la nano-porosidad de los geles formados durante la hidratación del ß-C2S y la mezcla 30-70 (T1-C3S- ß-C2S son mayores que los correspondientes a los geles del T1-C3S, y la mezcla 70-30; esta diferencia disminuye con el tiempo de hidratación. Estos cambios coinciden con los resultados de nanoindentación que indican un aumento de volumen relativo de las fases C-S-H con una densidad menor en el caso del ß-C2S y la mezcla 30-70. Al aumentar el tiempo de hidratación, el volumen relativo de fases C-S-H de mayor densidad aumenta a expensas de aquellas de menor densidad. Importantes correlaciones cuantitativas se establecen entre las características texturales y la longitud de cadena media del gel C-S-H, determinada mediante RMN-MAS de 29Si.

  11. MoS2 Nanocube structures as catalysts for electrochemical H2 evolution from acidic aqueous solutions

    OpenAIRE

    Maijenburg, A.W.; Regis, M.; Hattori, A.N.; Tanaka, H.; Choi, K.-S.; ten Elshof, Johan E.

    2014-01-01

    Core–shell PMMA–Au nanocube structures made by a combination of nanoimprint lithography and sidewall deposition were used as template for electrodeposition of MoS2, Ni, and Pt. Linear sweep voltammetry experiments obtained in an aqueous solution containing 0.29 M H2SO4 (pH 0.24) showed that the onset potential of the core–shell–shell PMMA–Au–MoS2 nanocube electrode for the hydrogen evolution reaction (HER) was shifted to the positive direction (i.e., requiring a lower overpotential) by 20–40 ...

  12. Population of the 3s state in hydrogen due to H+, H2+ and H3+ impact on ethylene, 1-butene and cis-2-butene

    International Nuclear Information System (INIS)

    Loyd, D.H.; Dawson, H.R.

    1983-01-01

    Absolute cross sections were measured for capture or dissociation into the 3s state of atomic hydrogen due to impact of 14-28 keV H + , H +2 and H +3 ions on ethylene, 1-butene and cis-2-butene. The cross sections obtained for the butene targets were almost identical and support the additive rule for cross sections. Ethylene cross sections were 21% lower than the values predicted by the additive rule, which agrees well with the observed trend toward reduction in total electron capture cross sections for protons on these gases at much higher energies

  13. Obtention of agricultural gypsum traced on 34 S (Ca34 SO4.2H2O), by chemical reaction between H234 SO4 and Ca(OH)2

    International Nuclear Information System (INIS)

    Rossete, Alessandra L.R.M.; Bendassolli, Jose A.; Ignoto, Raquel de Fatima; Batagello, Hugo Henrique

    2002-01-01

    The gypsum (CaSO 4 .2H 2 O) has double function in the soil: as source of calcium and sulfur and reducing agent of aluminum saturation. The sulfur for the plants has acting in the vital functions and it is proven fact increase of the S deficiency in Brazilian soils. The isotope tracer 34 S can elucidate important aspects in the sulfur cycle. The Ca 34 SO 4 .2H 2 O was obtained by chemical reaction between Ca(OH) 2 and H 2 34 SO 4 solution. The acid was obtained by chromatography ionic change, using cationic resin Dowex 50WX8 and Na 2 34 SO 4 solution. The reaction was realized under slow agitation. After the reaction, the precipitate was separated and dried in ventilated stove at 60 deg C temperature. The Mass of the Ca 34 SO 4 .2H 2 O produced was determined by method gravimetric. This way, a system contends resin 426 cm 3 , considering volume of 2.2 liters can be obtained a solution contends 44.2 g of H 2 34 SO 4 , theoretically could be produced 78.0 g of Ca 34 SO 4 .2H 2 O approximately. With results of the tests were verified that there was not total precipitation of the Ca 34 SO 4 .2H 2 O. Were produced 73.7± 0.6 g of Ca 34 SO 4 .2H 2 O representing average income 94.6±0.8 %. The purity of the produced CaSO 4 .2H 2 O was 98%. (author)

  14. Transfer of deuterium from [1R-2H]- and [1S-2H] ethanol to reduced metabolites formed in vivo

    International Nuclear Information System (INIS)

    Cronholm, T.; Fors, C.

    1977-01-01

    Since alcohol dehydrogenase is stereospecific and only removes the 1-pro-R hydrogen of ethanol, it is possible to label selectively NADH formed at the alcohol dehydrogenase by using [1R- 2 H]-ethanol. In contrast, [1S- 2 H]ethanol may be used to label NADH formed in the aldehyde dehydrogenase reaction. The present investigation is an attempt to study the relationship between the NADH pools at these two dehydrogenases, with special reference to subcellular localization, by using chiral monodeuteroethanols

  15. Total scattering cross-sections for the systems nH2 + nH2, pH2 + pH2, nD2 + nD2, oD2 + oD2 and HD + HD for relative energies below ten milli-electron volts

    International Nuclear Information System (INIS)

    Johnson, D.L.

    1979-01-01

    Relative total scattering cross sections for nH 2 + nH 2 , pH 2 + pH 2 , nD 2 + nD 2 , oD 2 + oD 2 , and HD + HD were measured with inclined nozzle beams derived from nozzle sources and intersecting at 21 0 . Both nozzles could be varied in temperature from 4.2K to 300K to provide the velocity range for the cross sections. The use of a parahydrogen converter allowed the measurement of the pH 2 + pH 2 and oD 2 + oD 2 cross sections. Cross sections for the H 2 + H 2 were measured over a relative velocity range of 200 m/s to 1450 m/s. The nH 2 + nH 2 results show an undulation in the velocity range between 350 m/s and 400 m/s that corresponds to a l = 3 orbiting resonance. Analysis of the pH 2 + pH 2 cross section indicates a l = 4 orbiting resonance near 586 m/s. This resonance has a peak energy of 1.79 meV and a measured energy width of 1.05 meV, both which agree well with theoretical predictions. The D 2 + D 2 cross sections have been measured in the velocity range between 190 m/s and 1000 m/s. No orbiting resonances have been observed, but in the oD 2 + oD 2 cross section a deep minimum between the l = 4 and the l = 5 resonances at low velocities is clearly suggested. Initial measurements of the HD + HD cross section suggests the presence of the l = 4 orbiting resonance near a relative velocity of 300 m/s. The experimental results for each system were normalized to the total cross sections, which were convoluted to account for experimental velocity and angular dispersions. Three different potentials were considered, but a chi-square fit of the data indicates that the Schaefer and Meyer potential, which has been theoretically obtained from first principles, provides the best overall description of the hydrogen systems in the low collisional energy range

  16. Precursory diffuse CO2 and H2S emission signatures of the 2011-2012 El Hierro submarine eruption, Canary Islands

    Science.gov (United States)

    Pérez, Nemesio M.; Padilla, Germán D.; Padrón, Eleazar; Hernández, Pedro A.; Melián, Gladys V.; Barrancos, José; Dionis, Samara; Nolasco, Dácil; Rodríguez, Fátima; Calvo, David; Hernández, Íñigo

    2012-08-01

    On October 12, 2011, a submarine eruption began 2 km off the coast of La Restinga, south of El Hierro Island. CO2 and H2S soil efflux were continuously measured during the period of volcanic unrest by using the accumulation chamber method at two different geochemical stations, HIE01 and HIE07. Recorded CO2 and H2S effluxes showed precursory signals that preceded the submarine eruption. Beginning in late August, the CO2 efflux time series started increasing at a relatively constant rate over one month, reaching a maximum of 19 gm-2d-1 one week before the onset of the submarine volcanic eruption. The H2S efflux time series at HIE07 showed a pulse in H2S emission just one day before the initiation of the submarine eruption, reaching peak values of 42 mg m-2 d-1, 10 times the average H2S efflux recorded during the observation period. Since CO2 and H2S effluxes are strongly influenced by external factors, we applied a multiple regression analysis to remove their contribution. A statistical analysis showed that the long-term trend of the filtered data is well correlated with the seismic energy. We find that these geochemical stations are important monitoring sites for evaluating the volcanic activity of El Hierro and that they demonstrate the potential of applying continuous monitoring of soil CO2 and H2S efflux to improve and optimize the detection of early warning signals of future volcanic unrest episodes at El Hierro. Continuous diffuse degassing studies would likely prove useful for monitoring other volcanoes during unrest episodes.

  17. Heme-dependent Metabolite Switching Regulates H2S Synthesis in Response to Endoplasmic Reticulum (ER) Stress.

    Science.gov (United States)

    Kabil, Omer; Yadav, Vinita; Banerjee, Ruma

    2016-08-05

    Substrate ambiguity and relaxed reaction specificity underlie the diversity of reactions catalyzed by the transsulfuration pathway enzymes, cystathionine β-synthase (CBS) and γ-cystathionase (CSE). These enzymes either commit sulfur metabolism to cysteine synthesis from homocysteine or utilize cysteine and/or homocysteine for synthesis of H2S, a signaling molecule. We demonstrate that a kinetically controlled heme-dependent metabolite switch in CBS regulates these competing reactions where by cystathionine, the product of CBS, inhibits H2S synthesis by the second enzyme, CSE. Under endoplasmic reticulum stress conditions, induction of CSE and up-regulation of the CBS inhibitor, CO, a product of heme oxygenase-1, flip the operating preference of CSE from cystathionine to cysteine, transiently stimulating H2S production. In contrast, genetic deficiency of CBS leads to chronic stimulation of H2S production. This metabolite switch from cystathionine to cysteine and/or homocysteine renders H2S synthesis by CSE responsive to the known modulators of CBS: S-adenosylmethionine, NO, and CO. Used acutely, it regulates H2S synthesis; used chronically, it might contribute to disease pathology. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. 11 CFR 102.11 - Petty cash fund (2 U.S.C. 432(h)(2)).

    Science.gov (United States)

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Petty cash fund (2 U.S.C. 432(h)(2)). 102.11 Section 102.11 Federal Elections FEDERAL ELECTION COMMISSION GENERAL REGISTRATION, ORGANIZATION, AND... and Congressional district) sought by such candidate. ...

  19. Tunneling microscopy of 2H-MoS2: A compound semiconductor surface

    OpenAIRE

    Weimer, M.; Kramar, J.; Bai, C.; Baldeschwieler, J. D.

    1988-01-01

    Molybdenum disulfide, a layered semiconductor, is an interesting material to study with the tunneling microscope because two structurally and electronically different atomic species may be probed at its surface. We report on a vacuum scanning tunneling microscopy study of 2H-MoS2. Atomic resolution topographs and current images show the symmetry of the surface unit cell and clearly reveal two distinct atomic sites in agreement with the well-known x-ray crystal structure.

  20. Adsorption and dissociation of H2S on Mo(1 0 0) surface by first-principles study

    International Nuclear Information System (INIS)

    Luo, Haijun; Cai, Jianqiu; Tao, Xiangming; Tan, Mingqiu

    2014-01-01

    Density-functional theory calculations had been used to investigate the adsorption and dissociation of H 2 S on Mo(1 0 0) surface. Adsorption mechanisms of H 2 S, HS, S and H on the Mo(1 0 0) surface were analyzed. H 2 S was found to be adsorbed at bridge, hollow and top sites with adsorption energies of −1.25, −1.03 and −0.92 eV, respectively. HS was strongly chemically absorbed at hollow, bridge and top sites with adsorption energies of −4.51, −4.08 and −3.45 eV, respectively, and sulfur and hydrogen preferred to be absorbed at hollow and bridge sites, respectively. In addition, potential energy profiles of H 2 S dissociation on Mo(1 0 0) had been constructed by a climbing image nudged elastic band method. Four possible dissociation pathways of the first H 2 S dehydrogenation were examined with reaction barriers of 0.28, 0.37, 0.075, and 0.21 eV, respectively, while the energy barrier to break the S-H bond of HS with or without hydrogen co-adsorption was almost the same low. This work showed that the decomposition of H 2 S on the molybdenum surface was kinetically and thermodynamically facile. Local densities of electronic states were further used to characterize the interaction between H 2 S and substrate.

  1. Formulation and Characterization of Cr2O3 Doped ZnO Thick Films as H2S Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. V. PATIL

    2009-09-01

    Full Text Available Cr2O3 doped ZnO thick films have been prepared by screen printing technique and firing process. These films were characterized by X-ray diffraction (XRD, Scanning electron microscopy (SEM, and EDX. H2S gas sensing properties of these films were investigated at different operating temperatures and different H2S concentrations. The 7 wt. % Cr2O3 doped ZnO thick films exhibits excellent H2S gas sensing properties with maximum sensitivity of 99.12 % at 300 oC in air atmosphere with fast response and recovery time.

  2. The synthesis of [2-3H2] taurine and [2-3H2] hypotaurine

    International Nuclear Information System (INIS)

    Fellman, J.H.

    1981-01-01

    The synthesis of [2- 3 H 2 ]-2-aminoethanesulfonate [2- 3 H]-taurine by the reduction of cyanomethanesulfonic acid with tritium gas is described. The conversion of [2- 3 H]-taurine and its 14 C and 35 S isotopic forms to 2-aminoethanesulfinate (hypotaurine) was accomplished by converting taurine to its corresponding sulfonyl chloride and reducing the latter with metallic zinc. (author)

  3. Responses of plants to sulfur containing air pollutants (H2S and SO2)

    NARCIS (Netherlands)

    Maas, Franciscus Marie

    1987-01-01

    Effects of air pollution by hydrogen sulfide (H2S) and sulfur dioxide (SO2) were already reported more than half a century ago. The wider range of pollution by SO2 is reflected in the number of publications concerning effects of SO2 on plants. The major part of the reported studies effects of SO2

  4. Antimicrobial Resistance and Molecular Investigation of H2S-Negative Salmonella enterica subsp. enterica serovar Choleraesuis Isolates in China.

    Directory of Open Access Journals (Sweden)

    Jing Xie

    Full Text Available Salmonella enterica subsp. enterica serovar Choleraesuis is a highly invasive pathogen of swine that frequently causes serious outbreaks, in particular in Asia, and can also cause severe invasive disease in humans. In this study, 21 S. Choleraesuis isolates, detected from 21 patients with diarrhea in China between 2010 and 2011, were found to include 19 H2S-negative S. Choleraesuis isolates and two H2S-positive isolates. This is the first report of H2S-negative S. Choleraesuis isolated from humans. The majority of H2S-negative isolates exhibited high resistance to ampicillin, chloramphenicol, gentamicin, tetracycline, ticarcillin, and trimethoprim-sulfamethoxazole, but only six isolates were resistant to norfloxacin. In contrast, all of the isolates were sensitive to cephalosporins. Fifteen isolates were found to be multidrug resistant. In norfloxacin-resistant isolates, we detected mutations in the gyrA and parC genes and identified two new mutations in the parC gene. Pulsed-field gel electrophoresis (PFGE, multilocus sequence typing (MLST, and clustered regularly interspaced short palindromic repeat (CRISPR analysis were employed to investigate the genetic relatedness of H2S-negative and H2S-positive S. Choleraesuis isolates. PFGE revealed two groups, with all 19 H2S-negative S. Choleraesuis isolates belonging to Group I and H2S-positive isolates belonging to Group II. By MLST analysis, the H2S-negative isolates were all found to belong to ST68 and H2S-positive isolates belong to ST145. By CRISPR analysis, no significant differences in CRISPR 1 were detected; however, one H2S-negative isolate was found to contain three new spacers in CRISPR 2. All 19 H2S-negative isolates also possessed a frame-shift mutation at position 760 of phsA gene compared with H2S-positive isolates, which may be responsible for the H2S-negative phenotype. Moreover, the 19 H2S-negative isolates have similar PFGE patterns and same mutation site in the phsA gene, these

  5. Antimicrobial Resistance and Molecular Investigation of H2S-Negative Salmonella enterica subsp. enterica serovar Choleraesuis Isolates in China.

    Science.gov (United States)

    Xie, Jing; Yi, Shengjie; Zhu, Jiangong; Li, Peng; Liang, Beibei; Li, Hao; Yang, Xiaoxia; Wang, Ligui; Hao, Rongzhang; Jia, Leili; Wu, Zhihao; Qiu, Shaofu; Song, Hongbin

    2015-01-01

    Salmonella enterica subsp. enterica serovar Choleraesuis is a highly invasive pathogen of swine that frequently causes serious outbreaks, in particular in Asia, and can also cause severe invasive disease in humans. In this study, 21 S. Choleraesuis isolates, detected from 21 patients with diarrhea in China between 2010 and 2011, were found to include 19 H2S-negative S. Choleraesuis isolates and two H2S-positive isolates. This is the first report of H2S-negative S. Choleraesuis isolated from humans. The majority of H2S-negative isolates exhibited high resistance to ampicillin, chloramphenicol, gentamicin, tetracycline, ticarcillin, and trimethoprim-sulfamethoxazole, but only six isolates were resistant to norfloxacin. In contrast, all of the isolates were sensitive to cephalosporins. Fifteen isolates were found to be multidrug resistant. In norfloxacin-resistant isolates, we detected mutations in the gyrA and parC genes and identified two new mutations in the parC gene. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and clustered regularly interspaced short palindromic repeat (CRISPR) analysis were employed to investigate the genetic relatedness of H2S-negative and H2S-positive S. Choleraesuis isolates. PFGE revealed two groups, with all 19 H2S-negative S. Choleraesuis isolates belonging to Group I and H2S-positive isolates belonging to Group II. By MLST analysis, the H2S-negative isolates were all found to belong to ST68 and H2S-positive isolates belong to ST145. By CRISPR analysis, no significant differences in CRISPR 1 were detected; however, one H2S-negative isolate was found to contain three new spacers in CRISPR 2. All 19 H2S-negative isolates also possessed a frame-shift mutation at position 760 of phsA gene compared with H2S-positive isolates, which may be responsible for the H2S-negative phenotype. Moreover, the 19 H2S-negative isolates have similar PFGE patterns and same mutation site in the phsA gene, these results indicated

  6. Synthesis of metals chalcogenides nano-particles from H{sub 2}X (X=S, Se, Te) produced electrochemically; Synthese de nanoparticules de chalcogenures de metaux a partir de H{sub 2}X (X=S, Se, Te) produit electrochimiquement

    Energy Technology Data Exchange (ETDEWEB)

    Bastide, S.; Tena-Zaera, R.; Alleno, E.; Godart, C.; Levy-Clement, C. [Centre National de la Recherche Scientifique (CNRS), Lab. de Chimie Metallurgique des Terres Rares, 94 - Thiais (France); Hodes, G. [Weizmann Institute of Science, Rehovot (Israel)

    2006-07-01

    In this work, an electrochemical method to produce H{sub 2}X (X=S, Se, Te) hydrides in a controlled way (without being able to store them) and to transfer them directly in the synthesis reactor has been perfected. By this method, the use of H{sub 2}Te has been possible. The method uses the reduction of the elementary chalcogenide in acid medium. The Te being conductor, it can be directly used as electrode, on the other hand S and Se are insulators. Nevertheless, graphite-S or Se conducing composite electrodes can also be used. When the electrolyte composition (pH, salts presence) is well adjusted, the essential of the cathodic current is consumed by the chalcogenide reduction (low evolution of H{sub 2}) with faradic yields of about 100% for H{sub 2}S and H{sub 2}Se and 40% for HeTe. The use of H{sub 2}X allows the synthesis of nano-particles of metals chalcogenides directly by reaction with dissolved metallic salts in aqueous or organic medium and precipitation. Thus it has been possible to prepare all the CdX compounds under the form of nano-particles of diameter between 3 and 5 nm by bubbling of the gaseous hydrides in aqueous acetate solutions of Cd. In producing concomitantly H{sub 2}S and H{sub 2}Se, nano-particles of solid solutions CdS{sub x}Se{sub 1-x} have been synthesized too. (O.M.)

  7. Microcapsules Containing pH-Responsive, Fluorescent Polymer-Integrated MoS2: An Effective Platform for in Situ pH Sensing and Photothermal Heating.

    Science.gov (United States)

    Park, Chan Ho; Lee, Sangmin; Pornnoppadol, Ghasidit; Nam, Yoon Sung; Kim, Shin-Hyun; Kim, Bumjoon J

    2018-03-14

    We report the design of a novel microcapsule platform for in situ pH sensing and photothermal heating, which involves the encapsulation of pH-responsive polymer-coated molybdenum disulfide (MoS 2 ) nanosheets (NSs) in microcapsules with an aqueous core and a semipermeable polymeric shell. The MoS 2 NSs were functionalized with pH-responsive polymers having fluorescent groups at the distal end to provide pH-sensitive Förster resonance energy transfer (FRET) effect. The pH-responsive polymers were carefully designed to produce a dramatic change in the polymer conformation, which translated to a change in the FRET efficiency near pH 7.0 in response to subtle pH changes, enabling the detection of cancer cells. The pH-sensitive MoS 2 NSs were microfluidically encapsulated within semipermeable membranes to yield microcapsules with a uniform size and composition. The microcapsules retained the MoS 2 NSs without leakage while allowing the diffusion of small ions and water through the membrane. At the same time, the membranes excluded adhesive proteins and lipids in the surrounding media, protecting the encapsulated MoS 2 NSs from deactivation and enabling in situ pH monitoring. Moreover, the encapsulated MoS 2 NSs showed high-performance photothermal heating, rendering the dual-functional microcapsules highly suitable for cancer diagnosis and treatment.

  8. Hydrates of the alkali trioxidomonosulfidomolybdates and -tungstates. K{sub 2}[(Mo/W)O{sub 3}S] . 1.5 H{sub 2}O and (Rb/Cs){sub 2}[(Mo/W)O{sub 3}S] . H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Lehner, Anna J.; Braitsch, Milan; Roehr, Caroline [Freiburg Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2012-11-01

    The trioxidomonosulfidomolybdate and -tungstate anions [(Mo/W)O{sub 3}S]{sup 2-} are the first products formed when passing H{sub 2}S gas through a solution of the oxidometalates. Their potassium, rubidium and cesium salt hydrates form as crystalline precipitates from these solutions depending on pH, the polarity of the solvent, educt concentrations and temperature. The structures of the sesqui- (K) and mono- (Rb, Cs) hydrates have been determined by means of X-ray single crystal diffraction data. The potassium sesquihydrates K{sub 2}[(Mo/W)O{sub 3}S] . 1.5 H{sub 2}O are isotypic and crystallize with a new structure type (monoclinic, space group C2/c, M = Mo/W: a = 987.0(2)/993.13(11), b = 831.75(14)/831.10(11), c = 1868.9(4)/1865.2(2) pm, {beta} = 99.34(2)/99.153(8) , R1 = 0.0352/0.0390). In the crystal structure the [(Mo/W)O{sub 3}S]{sup 2-} anions are connected via hydrogen bonds to form columns along the c direction. Channels containing only water molecules run along the [101] direction. The dehydration process proceeds in a topotactic reaction between 60 to 95 C and yields crystals of the anhydrous salts K{sub 2}[(Mo/W)O{sub 3}S]. The two different K+ cations exhibit a 5 + 3 and 5 + 2 O/S coordination. The heavier alkali metal cations form the four monohydrates (Rb/Cs){sub 2}[(Mo/W)O{sub 3}S] . H{sub 2}O (trigonal rhombohedral, space group R anti 3m) with lattice parameters for the Rb/Cs molybdates of a = 621.17(6)/624.62(10), c = 3377.9(4)/3388.6(8) pm (R1 = 0.0505/0.0734) and the tungstates of a = 642.80(3)/643.3(4), c = 3532.8(3)/3566(4) pm (R1 = 0.0348/0.0660). In the structures the 3m symmetrical tetrahedra are arranged to form double layers in such a way, that the O{sub 3} bases of the tetrahedra are pointing towards each other in a staggered conformation. These double layers are stacked in the c direction in a rhombohedral sequence. In these hydrates, there are no distinct hydrogen bonds. Instead, partially disordered pairs of H{sub 2}O molecules are

  9. Textural and mechanical characterization of C-S-H gels from hydration of synthetic T1-C{sub 3}S, {beta}-C{sub 2}S and their blends; Caracterizacion textural y mecanica de geles C-S-H formados en la hidratacion de muestras sinteticas T1-C{sub 3}S, {beta}-C{sub 2}S y sus mezclas

    Energy Technology Data Exchange (ETDEWEB)

    Goni, S.; Guerrero, A.; Puertas, F.; Hernandez, M. S.; Palacios, M.; Dolado, J. S.; Zhu, W.; Howind, T.

    2011-07-01

    The textural and mechanical characterization of C-S-H gels formed from the hydration of pure T1-C{sub 3}S, {beta}-C{sub 2}S and their blends are studied by Nitrogen sorption and nano indentation experiments. The surface area and nano porosity of C-S-H gels formed from the hydration of {beta}-C{sub 2}S and the 30-70 (T1-C{sub 3}S and {beta}-C{sub 2}S mixture) are higher than those from hydration of T1-C{sub 3}S, and 70-30, with the difference decreasing with hydration age. Such changes are well supported by findings of nano indentation study, which shows the greater relative volume of C-S-H phases with lower densities in the {beta}-C{sub 2}S and the 30-70 pastes. With the increase in hydration age, the relative volume of C-S-H phases with higher densities increased at the expenses of those with lower density. Important quantitative correlations were found among these textural characteristics and the mean chain length, determined from {sup 2}9Si magic-angle-spinning (MAS) NMR, of the C-S-H gels. (Author) 36 refs.

  10. H3S10ph broadly marks early-replicating domains in interphase ESCs and shows reciprocal antagonism with H3K9me2.

    Science.gov (United States)

    Chen, Carol C L; Goyal, Preeti; Karimi, Mohammad M; Abildgaard, Marie H; Kimura, Hiroshi; Lorincz, Matthew C

    2018-01-01

    Phosphorylation of histone H3 at serine 10 (H3S10ph) by Aurora kinases plays an important role in mitosis; however, H3S10ph also marks regulatory regions of inducible genes in interphase mammalian cells, implicating mitosis-independent functions. Using the fluorescent ubiquitin-mediated cell cycle indicator (FUCCI), we found that 30% of the genome in interphase mouse embryonic stem cells (ESCs) is marked with H3S10ph. H3S10ph broadly demarcates gene-rich regions in G1 and is positively correlated with domains of early DNA replication timing (RT) but negatively correlated with H3K9me2 and lamin-associated domains (LADs). Consistent with mitosis-independent kinase activity, this pattern was preserved in ESCs treated with Hesperadin, a potent inhibitor of Aurora B/C kinases. Disruption of H3S10ph by expression of nonphosphorylatable H3.3S10A results in ectopic spreading of H3K9me2 into adjacent euchromatic regions, mimicking the phenotype observed in Drosophila JIL-1 kinase mutants . Conversely, interphase H3S10ph domains expand in Ehmt1 (also known as Glp ) null ESCs, revealing that H3S10ph deposition is restricted by H3K9me2. Strikingly, spreading of H3S10ph at RT transition regions (TTRs) is accompanied by aberrant transcription initiation of genes co-oriented with the replication fork in Ehmt1 -/- and Ehmt2 -/- ESCs, indicating that establishment of repressive chromatin on the leading strand following DNA synthesis may depend upon these lysine methyltransferases. H3S10ph is also anti-correlated with H3K9me2 in interphase murine embryonic fibroblasts (MEFs) and is restricted to intragenic regions of actively transcribing genes by EHMT2. Taken together, these observations reveal that H3S10ph may play a general role in restricting the spreading of repressive chromatin in interphase mammalian cells. © 2018 Chen et al.; Published by Cold Spring Harbor Laboratory Press.

  11. A study on H{sub 2}S permeability of CsHSO{sub 4} membranes

    Energy Technology Data Exchange (ETDEWEB)

    Mbah, Jonathan; Wolan, John T. [Department of Chemical and Biomedical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620 (United States); Clean Energy Research Center, College of Engineering, University of South Florida, Tampa, FL 33617 (United States); Krakow, Burton [Clean Energy Research Center, College of Engineering, University of South Florida, Tampa, FL 33617 (United States); Stefanakos, Elias [Clean Energy Research Center, College of Engineering, University of South Florida, Tampa, FL 33617 (United States); Department of Electrical Engineering, College of Engineering, University of South Florida, Tampa, FL 33617 (United States)

    2009-03-15

    The gas permeability of H{sub 2}S gas at 150 C through ultra-thin cesium hydrogen sulfate (CsHSO{sub 4}) membranes has been investigated. Gas chromatography-mass spectrometry analyses indicate that CsHSO{sub 4} membrane is impermeable to H{sub 2}S gas under test conditions. The apparent micropore diameter of the membrane averaged between 9.5 and 11.5 Aa with a maximum permeance of 0.09 Barrer (6.75 x 10{sup -19} m{sup 2} s{sup -1} Pa{sup -1}). Atomic force microscope and X-ray diffraction analyses show respectively that the surface morphology and crystal structure of the membranes are preserved, with no adverse effect from prolonged exposure to H{sub 2}S gas. Electrochemical impedance spectroscopy analysis confirm over a 30% decrease in membrane resistance via an 80% reduction in membrane thickness. (author)

  12. Hydrogen sulfide (H{sub 2}S) and sour gas effects on the eye. A historical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, Timothy William [Environmental Health, Calgary Health Region, 1509 Centre St SW, Calgary Alberta, T2G 2E6 (Canada)]. E-mail: tim.lambert@calgaryheathregion.ca; Goodwin, Verona Marie [VM Goodwin Research and Consulting Ltd. (Canada); Stefani, Dennis [Environmental Health, Calgary Health Region, 1509 Centre St SW, Calgary Alberta, T2G 2E6 (Canada); Strosher, Lisa [Environmental Health, Calgary Health Region, 1509 Centre St SW, Calgary Alberta, T2G 2E6 (Canada)

    2006-08-15

    The toxicology of hydrogen sulfide (H{sub 2}S) and sour gas on the eye has a long history beginning at least with Ramazzini's observations [Ramazzini B. Diseases of Workers-De Morbis Artificum Diatriba-1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc.; 1964. 98-99 pp.]. In contrast, a recent review by Alberta Health and Wellness (AHW Report) concluded that there is little evidence of eye irritation following short-term exposures to H{sub 2}S at concentrations up to 100 ppm and that the H{sub 2}S literature on the eye is a series of unsubstantiated claims reproduced in review articles dating back to the 1930s [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide: a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In this paper, we evaluated this claim through a historical review of the toxicology of the eye. Ramazzini noted the effects of sewer gas on the eye [Ramazzini B. Diseases of Workers-De Morbis Artificum Diatriba-1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc. 1964. 98-99 pp.]. Lehmann experimentally showed eye effects in men at 70-90 ppm H{sub 2}S and also in animals [Lehmann K. Experimentalle Studien uber den Einfluss technisch und hygienisch wichtiger Gase und Dampfe auf den Organismus. Arch Hyg 1892;14:135-189]. In 1923, Sayers, Mitchell and Yant reported eye effects in animals and men at 50 ppm H{sub 2}S. Barthelemy showed eye effects in animals and men at 20 ppm H{sub 2}S [Barthelemy HL. Ten years' experience with industrial hygiene in connection with the manufacture of viscose rayon. J Ind Hyg Toxicol 1939;21:141-51]. Masure experimentally showed that H{sub 2}S is the causative agent of eye impacts in animals and men [Masure R. La Keratoconjunctivite des filatures de viscose; etude clinique and experiementale. Rev Belge Pathol 1950;20:297-341]. Michal upon microscopic examination of the rat's cornea, found nuclear

  13. MoS2 Nanocube structures as catalysts for electrochemical H2 evolution from acidic aqueous solutions

    NARCIS (Netherlands)

    Maijenburg, A.W.; Regis, M.; Hattori, A.N.; Tanaka, H.; Choi, K.-S.; ten Elshof, Johan E.

    2014-01-01

    Core–shell PMMA–Au nanocube structures made by a combination of nanoimprint lithography and sidewall deposition were used as template for electrodeposition of MoS2, Ni, and Pt. Linear sweep voltammetry experiments obtained in an aqueous solution containing 0.29 M H2SO4 (pH 0.24) showed that the

  14. Depletion of H2S during obesity enhances store-operated Ca2+ entry in adipose tissue macrophages to increase cytokine production.

    Science.gov (United States)

    Velmurugan, Gopal V; Huang, Huiya; Sun, Hongbin; Candela, Joseph; Jaiswal, Mukesh K; Beaman, Kenneth D; Yamashita, Megumi; Prakriya, Murali; White, Carl

    2015-12-15

    The increased production of proinflammatory cytokines by adipose tissue macrophages (ATMs) contributes to chronic, low-level inflammation during obesity. We found that obesity in mice reduced the bioavailability of the gaseous signaling molecule hydrogen sulfide (H2S). Steady-state, intracellular concentrations of H2S were lower in ATMs isolated from mice with diet-induced obesity than in ATMs from lean mice. In addition, the intracellular concentration of H2S in the macrophage cell line RAW264.7 was reduced during an acute inflammatory response evoked by the microbial product lipopolysaccharide (LPS). Reduced intracellular concentrations of H2S led to increased Ca(2+) influx through the store-operated Ca(2+) entry (SOCE) pathway, which was prevented by the exogenous H2S donor GYY4137. Furthermore, GYY4137 inhibited the Orai3 channel, a key component of the SOCE machinery. The enhanced production of proinflammatory cytokines by RAW264.7 cells and ATMs from obese mice was reduced by exogenous H2S or by inhibition of SOCE. Together, these data suggest that the depletion of macrophage H2S that occurs during acute (LPS-induced) or chronic (obesity) inflammation increases SOCE through disinhibition of Orai3 and promotes the production of proinflammatory cytokines. Copyright © 2015, American Association for the Advancement of Science.

  15. Induction of a Torpor-Like State by 5’-AMP Does Not Depend on H2S Production

    Science.gov (United States)

    Dugbartey, George J.; Bouma, Hjalmar R.; Strijkstra, Arjen M.; Boerema, Ate S.; Henning, Robert H.

    2015-01-01

    Background Therapeutic hypothermia is used to reduce ischemia/reperfusion injury (IRI) during organ transplantation and major surgery, but does not fully prevent organ injury. Interestingly, hibernating animals undergo repetitive periods of low body temperature called ‘torpor’ without signs of organ injury. Recently, we identified an essential role of hydrogen sulfide (H2S) in entrance into torpor and preservation of kidney integrity during hibernation. A torpor-like state can be induced pharmacologically by injecting 5’-Adenosine monophosphate (5’-AMP). The mechanism by which 5’-AMP leads to the induction of a torpor-like state, and the role of H2S herein, remains to be unraveled. Therefore, we investigated whether induction of a torpor-like state by 5-AMP depends on H2S production. Methods To study the role of H2S on the induction of torpor, amino-oxyacetic acid (AOAA), a non-specific inhibitor of H2S, was administered before injection with 5'-AMP to block endogenous H2S production in Syrian hamster. To assess the role of H2S on maintenance of torpor induced by 5’-AMP, additional animals were injected with AOAA during torpor. Key Results During the torpor-like state induced by 5’-AMP, the expression of H2S- synthesizing enzymes in the kidneys and plasma levels of H2S were increased. Blockade of these enzymes inhibited the rise in the plasma level of H2S, but neither precluded torpor nor induced arousal. Remarkably, blockade of endogenous H2S production was associated with increased renal injury. Conclusions Induction of a torpor-like state by 5’-AMP does not depend on H2S, although production of H2S seems to attenuate renal injury. Unraveling the mechanisms by which 5’-AMP reduces the metabolism without organ injury may allow optimization of current strategies to limit (hypothermic) IRI and improve outcome following organ transplantation, major cardiac and brain surgery. PMID:26295351

  16. Third-order optical model analysis of e+-H(2s), e+-He(21S) and e+-He(23S) elastic scattering at intermediate energies

    International Nuclear Information System (INIS)

    Vucic, S.; Potvliege, R.M.; Joachain, C.J.; Louvain Univ., Louvain-la-Neuve

    1987-01-01

    We study the elastic scattering of electrons by the metastable states H(2s), He(2 1 S) and He(2 3 S) at intermediate energies within the framework of the third-order optical potential theory. The first-, second- and third-order contributions to the optical potential are analysed separately, and are compared with the corresponding quantities for e - H(1s) and e - He(1 1 S) elastic scattering. Results for positron impact scattering are also presented. (author)

  17. Structural stability of coplanar 1T-2H superlattice MoS2 under high energy electron beam

    Science.gov (United States)

    Reshmi, S.; Akshaya, M. V.; Satpati, Biswarup; Basu, Palash Kumar; Bhattacharjee, K.

    2018-05-01

    Coplanar heterojunctions composed of van der Waals layered materials with different structural polymorphs have drawn immense interest recently due to low contact resistance and high carrier injection rate owing to low Schottky barrier height. Present research has largely focused on efficient exfoliation of these layered materials and their restacking to achieve better performances. We present here a microwave assisted easy, fast and efficient route to induce high concentration of metallic 1T phase in the original 2H matrix of exfoliated MoS2 layers and thus facilitating the formation of a 1T-2H coplanar superlattice phase. High resolution transmission electron microscopy (HRTEM) investigations reveal formation of highly crystalline 1T-2H hybridized structure with sharp interface and disclose the evidence of surface ripplocations within the same exfoliated layer of MoS2. In this work, the structural stability of 1T-2H superlattice phase during HRTEM measurements under an electron beam of energy 300 keV is reported. This structural stability could be either associated to the change in electronic configuration due to induction of the restacked hybridized phase with 1T- and 2H-regions or to the formation of the surface ripplocations. Surface ripplocations can act as an additional source of scattering centers to the electron beam and also it is possible that a pulse train of propagating ripplocations can sweep out the defects via interaction from specific areas of MoS2 sheets.

  18. Metallic 1T-LixMoS2 Cocatalyst Significantly Enhanced the Photocatalytic H2 Evolution over Cd0.5Zn0.5S Nanocrystals under Visible Light Irradiation.

    Science.gov (United States)

    Du, Hong; Guo, Hong-Li; Liu, Ya-Nan; Xie, Xiao; Liang, Kuang; Zhou, Xiao; Wang, Xin; Xu, An-Wu

    2016-02-17

    In the present work, metallic 1T-LixMoS2 is utilized as a novel cocatalyst for Cd0.5Zn0.5S photocatalyst. The obtained LixMoS2/Cd0.5Zn0.5S hybrids show excellent photocatalytic performance for H2 generation from aqueous solution containing Na2S and Na2SO3 under splitting visible light illumination (λ ≥ 420 nm) without precious metal cocatalysts. It turns out that a certain amount of intercalating Li(+) ions ultimately drives the transition of MoS2 crystal from semiconductor triagonal phase (2H phase) to metallic phase (1T phase). The distinct properties of 1T-LixMoS2 promote the efficient separation of photoexcited electrons and holes when used as cocatalyst for Cd0.5Zn0.5S photocatalyst. As compared to 2H-MoS2 nanosheets only having edge active sites, photoinduced electrons not only transfer to the edge sites of 1T-LixMoS2, but also to the plane active sites of 1T-LixMoS2 nanosheets. The content of LixMoS2 in hybrid photocatalysts influences the photocatalytic activity. The optimal 1T-LixMoS2 (1.0 wt %)/Cd0.5Zn0.5S nanojunctions display the best activity for hydrogen production, achieving a hydrogen evolution rate of 769.9 μmol h(-1), with no use of noble metal loading, which is about 3.5 times higher than that of sole Cd0.5Zn0.5S, and 2 times higher than that of 2H-MoS2 (1.0 wt %)/Cd0.5Zn0.5S samples. Our results demonstrate that Li(+)-intercalated MoS2 nanosheets with high conductivity, high densities of active sites, low cost, and environmental friendliness are a prominent H2 evolution cocatalyst that might substitute for noble metal for potential hydrogen energy applications.

  19. Garlic oil polysulfides: H2S- and O2-independent prooxidants in buffer and antioxidants in cells

    Science.gov (United States)

    DeLeon, Eric R.; Gao, Yan; Huang, Evelyn

    2016-01-01

    The health benefits of garlic and other organosulfur-containing foods are well recognized and have been attributed to both prooxidant and antioxidant activities. The effects of garlic are surprisingly similar to those of hydrogen sulfide (H2S), which is also known to be released from garlic under certain conditions. However, recent evidence suggests that polysulfides, not H2S, may be the actual mediator of physiological signaling. In this study, we monitored formation of H2S and polysulfides from garlic oil in buffer and in human embryonic kidney (HEK) 293 cells with fluorescent dyes, 7-azido-4-methylcoumarin and SSP4, respectively and redox activity with two redox indicators redox-sensitive green fluorescent protein (roGFP) and DCF. Our results show that H2S release from garlic oil in buffer requires other low-molecular-weight thiols, such as cysteine (Cys) or glutathione (GSH), whereas polysulfides are readily detected in garlic oil alone. Administration of garlic oil to cells rapidly increases intracellular polysulfide but has minimal effects on H2S unless Cys or GSH are also present in the extracellular medium. We also observed that garlic oil and diallyltrisulfide (DATS) potently oxidized roGFP in buffer but did not affect DCF. This appears to be a direct polysulfide-mediated oxidation that does not require a reactive oxygen species intermediate. Conversely, when applied to cells, garlic oil became a significant intracellular reductant independent of extracellular Cys or GSH. This suggests that intracellular metabolism and further processing of the sulfur moieties are necessary to confer antioxidant properties to garlic oil in vivo. PMID:27101293

  20. Electron Excess Doping and Effective Schottky Barrier Reduction on the MoS2/h-BN Heterostructure.

    Science.gov (United States)

    Joo, Min-Kyu; Moon, Byoung Hee; Ji, Hyunjin; Han, Gang Hee; Kim, Hyun; Lee, Gwanmu; Lim, Seong Chu; Suh, Dongseok; Lee, Young Hee

    2016-10-12

    Layered hexagonal boron nitride (h-BN) thin film is a dielectric that surpasses carrier mobility by reducing charge scattering with silicon oxide in diverse electronics formed with graphene and transition metal dichalcogenides. However, the h-BN effect on electron doping concentration and Schottky barrier is little known. Here, we report that use of h-BN thin film as a substrate for monolayer MoS 2 can induce ∼6.5 × 10 11 cm -2 electron doping at room temperature which was determined using theoretical flat band model and interface trap density. The saturated excess electron concentration of MoS 2 on h-BN was found to be ∼5 × 10 13 cm -2 at high temperature and was significantly reduced at low temperature. Further, the inserted h-BN enables us to reduce the Coulombic charge scattering in MoS 2 /h-BN and lower the effective Schottky barrier height by a factor of 3, which gives rise to four times enhanced the field-effect carrier mobility and an emergence of metal-insulator transition at a much lower charge density of ∼1.0 × 10 12 cm -2 (T = 25 K). The reduced effective Schottky barrier height in MoS 2 /h-BN is attributed to the decreased effective work function of MoS 2 arisen from h-BN induced n-doping and the reduced effective metal work function due to dipole moments originated from fixed charges in SiO 2 .

  1. Fluorescence Quenching of Dendrimer-Encapsulated CdS Quantum Dots for the Detection of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyojung; Kim, Hai Dong; Kim, Joohoon [Kyung Hee Un iversity, Seoul (Korea, Republic of)

    2016-02-15

    Hydrogen peroxide (H{sub 2}O{sub 2}) exists in natural environments as a byproduct of various enzymatic and photochemical reactions. Various approaches have been reported for the synthesis of cadmium sulfide (CdS) QDs using dendrimers, which can be categorized mainly into two general approaches. The first approach utilizes dendrimers as capping agents, resulting in the formation of agglomerates of spatially segregated QDs stabilized by multiple dendrimers. We have described the synthesis and characterization of the CdS QDs using G6-NH{sub 2} dendrimers. By controlling the molar ratios (n = Cd2+/G6-NH{sub 2}) between the Cd{sup 2+} ions and G6-NH{sub 2} dendrimers, we synthesized a set of CdS QDs with different structural and optical properties. Importantly, the synthesized CdS QDs exhibited H{sub 2}O{sub 2}-sensitive fluorescence, which can be utilized for the detection of H{sub 2}O{sub 2}. Especially, the CdS QDs with n = 64 displayed a Stern–Volmer relationship between the fluorescence of the CdS QDs and the concentration of H{sub 2}O{sub 2}, as well as the strongest fluorescence among the set of the synthesized CdS QDs. Since core-shell structures of QDs often result in enhanced stability and quantum efficiency of the QDs, we are currently working on core-shell structured QDs prepared using dendrimers to improve their stability and quantum yield compared to the CdS QDs reported in the present study.

  2. PHOTOCHEMISTRY IN TERRESTRIAL EXOPLANET ATMOSPHERES. II. H{sub 2}S AND SO{sub 2} PHOTOCHEMISTRY IN ANOXIC ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Hu Renyu; Seager, Sara; Bains, William, E-mail: hury@mit.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-05-20

    Sulfur gases are common components in the volcanic and biological emission on Earth, and are expected to be important input gases for atmospheres on terrestrial exoplanets. We study the atmospheric composition and the spectra of terrestrial exoplanets with sulfur compounds (i.e., H{sub 2}S and SO{sub 2}) emitted from their surfaces. We use a comprehensive one-dimensional photochemistry model and radiative transfer model to investigate the sulfur chemistry in atmospheres ranging from reducing to oxidizing. The most important finding is that both H{sub 2}S and SO{sub 2} are chemically short-lived in virtually all types of atmospheres on terrestrial exoplanets, based on models of H{sub 2}, N{sub 2}, and CO{sub 2} atmospheres. This implies that direct detection of surface sulfur emission is unlikely, as their surface emission rates need to be extremely high (>1000 times Earth's volcanic sulfur emission) for these gases to build up to a detectable level. We also find that sulfur compounds emitted from the surface lead to photochemical formation of elemental sulfur and sulfuric acid in the atmosphere, which would condense to form aerosols if saturated. For terrestrial exoplanets in the habitable zone of Sun-like stars or M stars, Earth-like sulfur emission rates result in optically thick haze composed of elemental sulfur in reducing H{sub 2}-dominated atmospheres for a wide range of particle diameters (0.1-1 {mu}m), which is assumed as a free parameter in our simulations. In oxidized atmospheres composed of N{sub 2} and CO{sub 2}, optically thick haze, composed of elemental sulfur aerosols (S{sub 8}) or sulfuric acid aerosols (H{sub 2}SO{sub 4}), will form if the surface sulfur emission is two orders of magnitude more than the volcanic sulfur emission of Earth. Although direct detection of H{sub 2}S and SO{sub 2} by their spectral features is unlikely, their emission might be inferred by observing aerosol-related features in reflected light with future generation

  3. Achieving Simultaneous CO2 and H2 S Conversion via a Coupled Solar-Driven Electrochemical Approach on Non-Precious-Metal Catalysts.

    Science.gov (United States)

    Ma, Weiguang; Wang, Hong; Yu, Wei; Wang, Xiaomei; Xu, Zhiqiang; Zong, Xu; Li, Can

    2018-03-19

    Carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) are generally concomitant with methane (CH 4 ) in natural gas and traditionally deemed useless or even harmful. Developing strategies that can simultaneously convert both CO 2 and H 2 S into value-added products is attractive; however it has not received enough attention. A solar-driven electrochemical process is demonstrated using graphene-encapsulated zinc oxide catalyst for CO 2 reduction and graphene catalyst for H 2 S oxidation mediated by EDTA-Fe 2+ /EDTA-Fe 3+ redox couples. The as-prepared solar-driven electrochemical system can realize the simultaneous conversion of CO 2 and H 2 S into carbon monoxide and elemental sulfur at near neutral conditions with high stability and selectivity. This conceptually provides an alternative avenue for the purification of natural gas with added economic and environmental benefits. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. H/sub 2/S-removal processes for low-Btu coal gas

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, M. S.

    1979-01-01

    Process descriptions are provided for seven methods of removing H/sub 2/S from a low-Btu coal-derived gas. The processes include MDEA, Benfield, Selexol, Sulfinol, Stretford, MERC Iron Oxide, and Molecular Sieve. Each of these processes was selected as representing a particular category of gas treating (e.g., physical solvent systems). The open literature contains over 50 processes for H/sub 2/S removal, of which 35 were briefly characterized in the literature survey. Using a technical evaluation of these 35 processes, 21 were eliminated as unsuitable for the required application. The remaining 14 processes represent six categories of gas treating. A seventh category, low-temperature solid sorption, was subsequently added. The processes were qualitatively compared within their respective categories to select a representative process in each of the seven categories.

  5. A H2S Donor GYY4137 Exacerbates Cisplatin-Induced Nephrotoxicity in Mice

    Directory of Open Access Journals (Sweden)

    Mi Liu

    2016-01-01

    Full Text Available Accumulating evidence demonstrated that hydrogen sulfide (H2S is highly involved in inflammation, oxidative stress, and apoptosis and contributes to the pathogenesis of kidney diseases. However, the role of H2S in cisplatin nephrotoxicity is still debatable. Here we investigated the effect of GYY4137, a novel slow-releasing H2S donor, on cisplatin nephrotoxicity in mice. Male C57BL/6 mice were pretreated with GYY4137 for 72 h prior to cisplatin injection. After cisplatin treatment for 72 h, mice developed obvious renal dysfunction and kidney injury as evidenced by elevated blood urea nitrogen (BUN and histological damage. Consistently, these mice also showed increased proinflammatory cytokines such as TNF-α, IL-6, and IL-1β in circulation and/or kidney tissues. Meanwhile, circulating thiobarbituric aid-reactive substances (TBARS and renal apoptotic indices including caspase-3, Bak, and Bax were all elevated. However, application of GYY4137 further aggravated renal dysfunction and kidney structural injury in line with promoted inflammation, oxidative stress, and apoptotic response following cisplatin treatment. Taken together, our results suggested that GYY4137 exacerbated cisplatin-induced nephrotoxicity in mice possibly through promoting inflammation, oxidative stress, and apoptotic response.

  6. Biological treatment of H(2)S using pellet activated carbon as a carrier of microorganisms in a biofilter.

    Science.gov (United States)

    Duan, Huiqi; Koe, Lawrence C C; Yan, Rong; Chen, Xiaoge

    2006-08-01

    Biological treatment is an emerging technology for treating off-gases from wastewater treatment plants. The most commonly reported odourous compound in off-gases is hydrogen sulfide (H(2)S), which has a very low odor threshold. This study aims to evaluate the feasibility of using a biological activated carbon as a novel packing material, to achieve a performance-enhanced biofiltration processes in treating H(2)S through an optimum balance and combination of the adsorption capacity with the biodegradation of H(2)S by the bacteria immobilized on the material. The biofilm was mostly developed through culturing the bacteria in the presence of carbon pellets in mineral media. Scanning electron microscopy (SEM) was used to identify the biofilm development on carbon surface. Two identical laboratory scale biofilters, one was operated with biological activated carbon (BAC) and another with virgin carbon without bacteria immobilization. Various concentrations of H(2)S (up to 125 ppmv) were used to determine the optimum column performance. A rapid startup (a few days) was observed for H(2)S removal in the biofilter. At a volumetric loading of 1600 m(3)m(-3)h(-1) (at 87 ppmv H(2)S inlet concentration), elimination capacity of the BAC (181 gH(2)Sm(-3)h(-1)) at removal efficiency (RE) of 94% was achieved. If the inlet concentration was kept at below 30 ppmv, high H(2)S removal (over 99%) was achieved at a gas retention time (GRT) as low as 2s, a value, which is shorter than most previously reported for biofilter operations. The bacteria population in the acidic biofilter demonstrated capacity for removal of H(2)S in a broad pH range (pH 1-7). There are experimental evidences showing that the spent BAC could be re-used as packing material in a biofilter based on BAC. Overall, the results indicated that an unprecedented performance could be achieved by using BAC as the supporting media for H(2)S biofiltration.

  7. Use of Drinking Water Sludge as Adsorbent for H2S Gas Removal from Biogas

    Directory of Open Access Journals (Sweden)

    Sucheela Polruang

    2017-01-01

    Full Text Available This paper reports the results of a research project, which attempts to produce a low-cost adsorbent material from waste (drinking water sludge. The main objective of this work is to study the characteristics of drinking water sludge for its adsorptive properties including morphology, surface area, porosity and chemical composition. The effect of activation conditions on H2S gas adsorption efficiency of drinking water sludge was experimented. In this study, raw drinking water sludge was divided into 3 groups. In the first group, drinking water sludge was only oven dried at 105°C. For the other 2 groups, drinking water sludge was soaked in 2.5 M NaOH solution. After soaking, the sludge was divided into 2 groups (group 2 and 3. The second group was washed with distilled water until pH 7; while the third group was not. Biogas from a swine farm was used with an initial H2S gas concentration in the range of 2,000 - 4,000 ppm. The material analysis showed that more surface area and total volume of sludge can be obtained after activated with NaOH. From the adsorption experiments, it was found that the highest adsorption capacity (qe of 87.94 mg H2S/g adsorptive material can be achieved by using sludge from the third group. Moreover, by adding of 20 wt% iron filing into sludge of the third group the adsorption capacity increased to 105.22 mg H2S/g adsorptive material. Drinking water sludge can be considered as a high potential energy saving and low cost adsorbent for removal of H2S.

  8. Sulfur fertilization and fungal infections affect the exchange of H(2)S and COS from agricultural crops.

    Science.gov (United States)

    Bloem, Elke; Haneklaus, Silvia; Kesselmeier, Jürgen; Schnug, Ewald

    2012-08-08

    The emission of gaseous sulfur (S) compounds by plants is related to several factors, such as the plant S status or fungal infection. Hydrogen sulfide (H(2)S) is either released or taken up by the plant depending on the ambient air concentration and the plant demand for S. On the contrary, carbonyl sulfide (COS) is normally taken up by plants. In a greenhouse experiment, the dependence of H(2)S and COS exchange with ambient air on the S status of oilseed rape (Brassica napus L.) and on fungal infection with Sclerotinia sclerotiorum was investigated. Thiol contents were determined to understand their influence on the exchange of gaseous S compounds. The experiment revealed that H(2)S emissions were closely related to pathogen infections as well as to S nutrition. S fertilization caused a change from H(2)S consumption by S-deficient oilseed rape plants to a H(2)S release of 41 pg g(-1) (dw) min(-1) after the addition of 250 mg of S per pot. Fungal infection caused an even stronger increase of H(2)S emissions with a maximum of 1842 pg g(-1) (dw) min(-1) 2 days after infection. Healthy oilseed rape plants acted as a sink for COS. Fungal infection caused a shift from COS uptake to COS releases. The release of S-containing gases thus seems to be part of the response to fungal infection. The roles the S-containing gases may play in this response are discussed.

  9. Planetary Nebulae with H2 Emission

    OpenAIRE

    Margarita Rosado; Lorena Arias

    2003-01-01

    Hacemos una revisión de la emisión en hidrogeno molecular (H2) de las nebulosas planetarias (NPs). Vemos como esta emisión se encuentra asociada a objetos de forma bipolar. Describimos los niveles de energía de la molécula de hidrogeno, los principales mecanismos para poblarlos (choques y fluorescencia) y las formas en que se puede discriminar que mecanismo opera. Proponemos que la cinemática del H2 también puede ser usada para discriminar el mecanismo de excitación de sus líneas de emisión. ...

  10. Isolation and structures of sulfonium salts derived from thioethers: [{o-C(6)H(4)(CH(2)SMe)(2)}H][NbF(6)] and [{[9]aneS(3)}H][NbF(6)].

    Science.gov (United States)

    Jura, Marek; Levason, William; Reid, Gillian; Webster, Michael

    2009-10-07

    Two very unusual sulfonium salts, [{o-C(6)H(4)(CH(2)SMe)(2)}H][NbF(6)] and [{[9]aneS(3)}H][NbF(6)], obtained from reaction of the thioethers with NbF(5) in CH(2)Cl(2) solution, are reported and their structures described; the eight-coordinate tetrafluoro Nb(v) cation of the dithioether is obtained from the same reaction.

  11. Enhanced photocatalytic H{sub 2} production on CdS nanorod using cobalt-phosphate as oxidation cocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Di, Tingmin; Zhu, Bicheng; Zhang, Jun; Cheng, Bei [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2016-12-15

    Highlights: • Co-Pi/CdS composites were synthesized by a simple photodeposition method. • The composites showed superior photocatalytic H{sub 2} production activity. • The optimal H{sub 2} production rate of Co-Pi/CdS was even higher than that of Pt-CdS. • Co-Pi is a good oxidation cocatalyst used for capture of photogenerated hole. - Abstract: Employing visible light responsive semiconductor for photocatalytic hydrogen production by water splitting is an efficient way for utilizing renewable solar energy to solve the depletion of fossil fuel and environmental contamination. Herein, we report enhanced photocatalytic H{sub 2}-production performance over CdS nanorod using cobalt-phosphate (Co-Pi) as a water oxdation cocatalyst. The optimal Co-Pi modified CdS nanocomposite photocatalyst with the Co-Pi content of 8.4 mol% has a superior visible light H{sub 2}-production rate of 13.3 mmol h{sup −1} g{sup −1} with an apparent quantum efficiency of 24.3% at 420 nm, which is even higher than that of 1 wt% Pt-CdS (11.3 mmol h{sup −1} g{sup −1}) under the same conditions. The enhanced visible-light photocatalytic H{sub 2} production activity was attributed to the hole trapping and collecting ability of Co-Pi cocatalyst, which could effectively suppress the recombination of photogenerated electron-hole pairs and increase the electron density for hydrogen production. This work shows a possibility of using earth-abundant Co-Pi as cocatalyst for enhancing photocatalytic H{sub 2} production.

  12. JMJD1B Demethylates H4R3me2s and H3K9me2 to Facilitate Gene Expression for Development of Hematopoietic Stem and Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Sihui Li

    2018-04-01

    Full Text Available Summary: The arginine methylation status of histones dynamically changes during many cellular processes, including hematopoietic stem/progenitor cell (HSPC development. The arginine methyltransferases and the readers that transduce the histone codes have been defined. However, whether arginine demethylation actively occurs in cells and what enzyme demethylates the methylarginine residues during various cellular processes are unknown. We report that JMJD1B, previously identified as a lysine demethylase for H3K9me2, mediates arginine demethylation of H4R3me2s and its intermediate, H4R3me1. We show that demethylation of H4R3me2s and H3K9me2s in promoter regions is correlated with active gene expression. Furthermore, knockout of JMJD1B blocks demethylation of H4R3me2s and/or H3K9me2 at distinct clusters of genes and impairs the activation of genes important for HSPC differentiation and development. Consequently, JMJD1B−/− mice show defects in hematopoiesis. Altogether, our study demonstrates that demethylase-mediated active arginine demethylation process exists in eukaryotes and that JMJD1B demethylates both H4R3me2s and H3K9me2 for epigenetic programming during hematopoiesis. : Li et al. identify the arginine demethylase (RDM activity of JMJD1B, a known lysine demethylase (KDM. They reveal that JMJD1B actively mediates demethylation of histone markers H4R3me2s and H3K9me2 in hematopoietic stem/progenitor cells (HSPCs. Keywords: JMJD1B, KDM3B, PRMT5, arginine demethylase, histone, epigenetic programming, gene expression, hematopoiesis

  13. Numerical modeling of injection and mineral trapping of CO2 withH2S and SO2 in a Sandstone Formation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianfu; Apps, John A.; Pruess, Karsten; Yamamoto, Hajime

    2004-09-07

    Carbon dioxide (CO{sub 2}) injection into deep geologic formations could decrease the atmospheric accumulation of this gas from anthropogenic sources. Furthermore, by co-injecting H{sub 2}S or SO{sub 2}, the products respectively of coal gasification or combustion, with captured CO{sub 2}, problems associated with surface disposal would be mitigated. We developed models that simulate the co-injection of H{sub 2}S or SO{sub 2} with CO{sub 2} into an arkose formation at a depth of about 2 km and 75 C. The hydrogeology and mineralogy of the injected formation are typical of those encountered in Gulf Coast aquifers of the United States. Six numerical simulations of a simplified 1-D radial region surrounding the injection well were performed. The injection of CO{sub 2} alone or co-injection with SO{sub 2} or H{sub 2}S results in a concentrically zoned distribution of secondary minerals surrounding a leached and acidified region adjacent to the injection well. Co-injection of SO{sub 2} with CO{sub 2} results in a larger and more strongly acidified zone, and alteration differs substantially from that caused by the co-injection of H{sub 2}S or injection of CO{sub 2} alone. Precipitation of carbonates occurs within a higher pH (pH > 5) peripheral zone. Significant quantities of CO{sub 2} are sequestered by ankerite, dawsonite, and lesser siderite. The CO{sub 2} mineral-trapping capacity of the formation can attain 40-50 kg/m{sup 3} medium for the selected arkose. In contrast, secondary sulfates precipitate at lower pH (pH < 5) within the acidified zone. Most of the injected SO{sub 2} is transformed and immobilized through alunite precipitation with lesser amounts of anhydrite and minor quantities of pyrite. The dissolved CO{sub 2} increases with time (enhanced solubility trapping). The mineral alteration induced by injection of CO{sub 2} with either SO{sub 2} or H{sub 2}S leads to corresponding changes in porosity. Significant increases in porosity occur in the acidified

  14. Solvothermal synthesis and characterisation of new one-dimensional indium and gallium sulphides: [C1N4H26]0.5[InS2] and [C1N4H26]0.5[GaS2

    International Nuclear Information System (INIS)

    Vaqueiro, Paz

    2006-01-01

    Two new main group metal sulphides, [C 1 N 4 H 26 ] 0.5 [InS 2 ] (1) and [C 1 N 4 H 26 ] 0.5 [GaS 2 ] (2) have been prepared solvothermally in the presence of 1,4-bis(3-aminopropyl)piperazine and their crystal structures determined by single-crystal X-ray diffraction. Both compounds are isostructural and crystallise in the monoclinic space group P2 1 /n (Z=4), with a=6.5628(5), b=11.2008(9), c=12.6611(9) A and β=94.410(4) o (wR=0.035) for compound (1) and a=6.1094(5), b=11.2469(9), c=12.7064(10) A and β=94.313(4) o (wR=0.021) for compound (2). The structure of [C 1 N 4 H 26 ] 0.5 [MS 2 ] (M=In,Ga) consists of one-dimensional [MS 2 ] - chains which run parallel to the crystallographic a axis and are separated by diprotonated amine molecules. These materials represent the first example of solvothermally prepared one-dimensional gallium and indium sulphides. -- Graphical abstract: [C 1 N 4 H 26 ] 0.5 [InS 2 ] and [C 1 N 4 H 26 ] 0.5 [GaS 2 ], prepared under solvothermal conditions, consist of one-dimensional [MS 2 ] - chains separated by diprotonated 1,4-bis(3-aminopropyl)piperazine molecules

  15. H2S-induced S-sulfhydration of lactate dehydrogenase a (LDHA) stimulates cellular bioenergetics in HCT116 colon cancer cells.

    Science.gov (United States)

    Untereiner, Ashley A; Oláh, Gabor; Módis, Katalin; Hellmich, Mark R; Szabo, Csaba

    2017-07-15

    Cystathionine-β-synthase (CBS) is upregulated and hydrogen sulfide (H 2 S) production is increased in colon cancer cells. The functional consequence of this response is stimulation of cellular bioenergetics and tumor growth and proliferation. Lactate dehydrogenase A (LDHA) is also upregulated in various colon cancer cells and has been previously implicated in tumor cell bioenergetics and proliferation. In the present study, we sought to determine the potential interaction between the H 2 S pathway and LDH activity in the control of bioenergetics and proliferation of colon cancer, using the colon cancer line HCT116. Low concentrations of GYY4137 (a slow-releasing H 2 S donor) enhanced mitochondrial function (oxygen consumption, ATP production, and spare respiratory capacity) and glycolysis in HCT116 cells. SiRNA-mediated transient silencing of LDHA attenuated the GYY4137-induced stimulation of mitochondrial respiration, but not of glycolysis. H 2 S induced the S-sulfhydration of Cys163 in recombinant LDHA, and stimulated LDHA activity. The H 2 S-induced stimulation of LDHA activity was absent in C163A LDHA. As shown in HCT116 cell whole extracts, in addition to LDHA activation, GYY4137 also stimulated LDHB activity, although to a smaller extent. Total cellular lactate and pyruvate measurements showed that in HCT116 cells LDHA catalyzes the conversion of pyruvate to lactate. Total cellular lactate levels were increased by GYY4137 in wild-type cells (but not in cells with LDHA silencing). LDHA silencing sensitized HCT116 cells to glucose oxidase (GOx)-induced oxidative stress; this was further exacerbated with GYY4137 treatment. Treatment with low concentrations of GYY4137 (0.3mM) or GOx (0.01U/ml) significantly increased the proliferation rate of HCT116 cells; the effect of GOx, but not the effect of GYY4137 was attenuated by LDHA silencing. The current report points to the involvement of LDHA in the stimulatory effect of H 2 S on mitochondrial respiration in colon

  16. Processo UV/H2O2 comos-tratamento para remoção de cor e polimento final em efluentes têxteis

    Directory of Open Access Journals (Sweden)

    Maria Eliza Nagel-Hassemer

    2012-01-01

    Full Text Available Several problems are involved the treatment plants of textile effluents, mainly the low efficiency of color removal. This paper presents an alternative of post-treatment by UV/H2O2 process, for color removal in biologically treated textile effluents. The tests were performed in a photochemical reactor and samples were taken at different times to perform analyses. Using 250 mgH2O2.L-1, 96% removal of color was verified, indicating the dyes degradation. A reduction of 84% of aromatics compounds, 90% of TSS removal, and a further reduction of the organic fraction were observed, demonstrating that the process is effective as a post-treatment of effluents from textile industries.

  17. Fabrication of 2D SnS2/g-C3N4 heterojunction with enhanced H2 evolution during photocatalytic water splitting.

    Science.gov (United States)

    Liu, Enzhou; Chen, Jibing; Ma, Yongning; Feng, Juan; Jia, Jia; Fan, Jun; Hu, Xiaoyun

    2018-08-15

    In this work, the 2D SnS 2 /g-C 3 N 4 heterojunctions were successfully prepared by heating the homogeneous dispersion of SnS 2 nanosheets and g-C 3 N 4 nanosheets using a microwave muffle. SEM, TEM and HRTEM images indicated that the SnS 2 nanosheets were loaded on the surface of the g-C 3 N 4 nanosheets. The UV-vis spectra show that the absorption intensity of the as-prepared samples was increased and the absorption range was also extended from 420 nm to approximately 600 nm. The H 2 production rate over 5 wt% SnS 2 /g-C 3 N 4 can reach 972.6 μmol·h -1 ·g -1 under visible light irradiation (λ > 420 nm) using TEOA as the sacrifice agent and Pt as the electron trap, which is 2.9 and 25.6 times higher than those of the pristine g-C 3 N 4 and SnS 2 , respectively. According to the obtained PL spectra, photocurrent and EIS spectra, the enhanced performance for H 2 generation over the heterojunctions is primarily ascribed to the rapid charge transfer arising from the suitable band gap positions leading to an improved photocatalytic performance. The recycling experiments indicated that the as-prepared composites exhibit good stability in H 2 production. Additionally, a possible enhanced mechanism for H 2 evolution was deduced based on the results obtained by various characterization techniques. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Hydrogen sulfide (H2S)/cystathionine γ-lyase (CSE) pathway contributes to the proliferation of hepatoma cells

    International Nuclear Information System (INIS)

    Pan, Yan; Ye, Shuang; Yuan, Dexiao; Zhang, Jianghong; Bai, Yang; Shao, Chunlin

    2014-01-01

    Highlights: • Inhibition of H 2 S/CSE pathway strongly stimulates cellular apoptosis. • Inhibition of H 2 S/CSE pathway suppresses cell growth by blocking EGFR pathway. • H 2 S/CSE pathway is critical for maintaining the proliferation of hepatoma cells. - Abstract: Hydrogen sulfide (H 2 S)/cystathionine γ-lyase (CSE) pathway has been demonstrated to play vital roles in physiology and pathophysiology. However, its role in tumor cell proliferation remains largely unclear. Here we found that CSE over-expressed in hepatoma HepG2 and PLC/PRF/5 cells. Inhibition of endogenous H 2 S/CSE pathway drastically decreased the proliferation of HepG2 and PLC/PRF/5 cells, and it also enhanced ROS production and mitochondrial disruption, pronounced DNA damage and increased apoptosis. Moreover, this increase of apoptosis was associated with the activation of p53 and p21 accompanied by a decreased ratio of Bcl-2/Bax and up-regulation of phosphorylated c-Jun N-terminal kinase (JNK) and caspase-3 activity. In addition, the negative regulation of cell proliferation by inhibition of H 2 S/CSE system correlated with the blockage of cell mitogenic and survival signal transduction of epidermal growth factor receptor (EGFR) via down-regulating the extracellular-signal-regulated kinase 1/2 (ERK1/2) activation. These results demonstrate that H 2 S/CSE and its downstream pathway contribute to the proliferation of hepatoma cells, and inhibition of this pathway strongly suppress the excessive growth of hepatoma cells by stimulating mitochondrial apoptosis and suppressing cell growth signal transduction

  19. Cadmium induced radioadaptive response via an ATM-independent H2S/cystathionine γ-lyase modulation

    International Nuclear Information System (INIS)

    Pan Yan; Yuan Dexiao; Zhang Jianghong; Shao Chunlin

    2011-01-01

    The combined exposure to environmental toxicants such as heavy metals and radiation is an important research area in health protection. Here we explored cadmium induced radioadaptive response (RAR) and investigated the role of hydrogen sulfide (H 2 S) and ATM kinase in this response. Our data showed that the cadmium ions with a sub-lethal concentration could induce RAR in Chang liver cells towards subsequent γ-irradiation and this response could be abrogated by DL-propargylglycine (PPG), the endogenous H 2 S synthetase inhibitor of cystathionine γ-lyase (CSE), but not by aminooxyacetic acid (AOAA), the inhibitor of cystathionine β-synthase (CBS). Moreover, the pretreatment of cells with NaHS also stimulated cellular adaptive response to radiation. Both cadmium treatment and irradiation up-regulated the expression of CSE protein in a time-dependent manner but had no influence on the expression of CBS protein. In the primed cells, the time course of CBS expression showed no significant difference with the cells treated with 2Gy irradiation alone, however, the CSE expression was easier to reach the maximum level, indicating a more efficient H 2 S production by CSE. Moreover, the cadmium-induced RAR was totally suppressed by KU-55933, a specific ATM inhibitor that did not change the CSE expression after radiation. However, exogenous H 2 S decreased the phosphorylation level of radiation-induced ATM. In conclusion, the present results demonstrate firstly that H 2 S is involved in the cadmium induced cross-adaptive response to challenging radiation. CSE, rather than CBS, may mainly responsible for the H 2 S production during this RAR which may also be mediated by ATM pathway. However, the activation of CSE is independent of ATM but could negatively regulate the phosphorylation of ATM.

  20. Control of Sulfidogenesis Through Bio-oxidation of H2S Coupled to (per)chlorate Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, Patrick [Univ. of California, Berkeley, CA (United States); Engelbrektson, Anna [Univ. of California, Berkeley, CA (United States); Hubbard, Christopher G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Metlagel, Zoltan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Csencsits, Roseann [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Auer, Manfred [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Conrad, Mark E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thieme, Jurgen [Brookhaven National Lab. (BNL), Upton, NY (United States); Northrup, Paul [Brookhaven National Lab. (BNL), Upton, NY (United States); Coates, John D. [Univ. of California, Berkeley, CA (United States)

    2014-04-04

    Here, we investigate H2S attenuation by dissimilatory perchlorate-reducing bacteria (DPRB). All DPRB tested oxidized H2S coupled to (per)chlorate reduction without sustaining growth. H2S was preferentially utilized over organic electron donors resulting in an enriched (34S)-elemental sulfur product. Electron microscopy revealed elemental sulfur production in the cytoplasm and on the cell surface of the DPRB Azospira suillum. We also propose a novel hybrid enzymatic-abiotic mechanism for H2S oxidation similar to that recently proposed for nitrate-dependent Fe(II) oxidation. The results of this study have implications for the control of biosouring and biocorrosion in a range of industrial environments.

  1. Fate and transport of metals in H2S-rich waters at a treatment wetland

    Directory of Open Access Journals (Sweden)

    Frandsen Angela K

    2001-02-01

    Full Text Available The aqueous geochemistry of Zn, Cu, Cd, Fe, Mn and As is discussed within the context of an anaerobic treatment wetland in Butte, Montana. The water being treated had a circum-neutral pH with high concentrations of trace metals and sulfate. Reducing conditions in the wetland substrate promoted bacterial sulfate reduction (BSR and precipitation of dissolved metal as sulfide minerals. ZnS was the most common sulfide phase found, and consisted of framboidal clusters of individual spheres with diameters in the submicron range. Some of the ZnS particles passed through the subsurface flow, anaerobic cells in suspended form. The concentration of "dissolved" trace metals (passing through a 0.45 μm filter was monitored as a function of H2S concentration, and compared to predicted solubilities based on experimental studies of aqueous metal complexation with dissolved sulfide. Whereas the theoretical predictions produce "U-shaped" solubility curves as a function of H2S, the field data show a flat dependence of metal concentration on H2S. Observed metal concentrations for Zn, Cu and Cd were greater than the predicted values, particularly at low H2S concentration, whereas Mn and As were undersaturated with their respective metal sulfides. Results from this study show that water treatment facilities employing BSR have the potential to mobilize arsenic out of mineral substrates at levels that may exceed regulatory criteria. Dissolved iron was close to equilibrium saturation with amorphous FeS at the higher range of sulfide concentrations observed (>0.1 mmol H2S, but was more likely constrained by goethite at lower H2S levels. Inconsistencies between our field results and theoretical predictions may be due to several problems, including: (i a lack of understanding of the form, valence, and thermodynamic stability of poorly crystalline metal sulfide precipitates; (ii the possible influence of metal sulfide colloids imparting an erroneously high "dissolved

  2. High-energy asymmetric supercapacitors based on free-standing hierarchical Co-Mo-S nanosheets with enhanced cycling stability.

    Science.gov (United States)

    Balamurugan, Jayaraman; Li, Chao; Peera, Shaik Gouse; Kim, Nam Hoon; Lee, Joong Hee

    2017-09-21

    Layered transition metal sulfides (TMS) are emerging as advanced materials for energy storage and conversion applications. In this work, we report a facile and cost-effective anion exchange technique to fabricate a layered, multifaceted, free standing, ultra-thin ternary cobalt molybdenum sulfide nanosheet (Co-Mo-S NS) architecture grown on a 3D porous Ni foam substrate. The unique Co-Mo layered double hydroxides are first synthesized as precursors and consequently transformed into ultra-thin Co-Mo-S NS. When employed as an electrode for supercapacitors, the Co-Mo-S NS delivered an ultra-high specific capacitance of 2343 F g -1 at a current density of 1 mA cm -2 with tremendous rate capability and extraordinary cycling performance (96.6% capacitance retention after 20 000 cycles). Furthermore, assembled Co-Mo-S/nitrogen doped graphene nanosheets (NGNS) in an asymmetric supercapacitor (ASC) device delivered an excellent energy density of 89.6 Wh kg -1 , an amazing power density of 20.07 kW kg -1 , and superior cycling performance (86.8% capacitance retention after 50 000 cycles). Such exceptional electrochemical performance of Co-Mo-S NS is ascribed to the good electrical contact with the 3D Ni foam, ultra-high contact area with the electrolyte, and enhanced architectural softening during the charging/discharging process. It is expected that the fabricated, unique, ultra-thin Co-Mo-S NS have great potential for future energy storage devices.

  3. (S-2-(2-Pyrrolidinio-1H-benzimidazol-3-ium dichloride monohydrate

    Directory of Open Access Journals (Sweden)

    Dai Jing

    2009-06-01

    Full Text Available In the title compound, C11H15N32+·2Cl−·H2O, one N atom of the imidazole ring and the N atom of the pyrrolidine ring are protonated. The crystal structure is stabilized by aromatic π–π interactions between the benzene rings of neighbouring benzimidazole systems [centroid–centroid duistance = 3.712 (2 Å]. The crystal structure is further stabilized by intermolecular N—H...Cl, O—H...Cl and N—H...O hydrogen bonds.

  4. DFT Calculation of IR Absorption Spectra for PCE-nH2O, TCE-nH2O, DCE-nH2O, VC-nH2O for Small and Water-Dominated Molecular Clusters

    Science.gov (United States)

    2017-10-31

    VC-nH2O for Small and Water-Dominated Molecular Clusters October 31, 2017 Approved for public release; distribution is unlimited. L. Huang S.g...Calculation of IR Absorption Spectra for PCE-nH2O, TCE-nH2O, DCE-nH2O, VC-nH2O for Small and Water-Dominated Molecular Clusters L. Huang,1 S.G...nH2O molecular clusters using density function theory (DFT). DFT can provide interpretation of absorption spectra with respect to molecular

  5. Detection of H2S gas at lower operating temperature using sprayed ...

    Indian Academy of Sciences (India)

    Nanostructured In2O3; thin films; spray pyrolysis; H2S gas sensor; low temperature. 1. Introduction ... nozzle to and fro frequency (16 cycles/min), nozzle to sub- ... were confirmed by measuring the thermoelectric power of the thin film samples.

  6. On the basic substances used in the separation process by isotope exchange H2S - H2O, at two temperatures, in view of producing heavy water

    International Nuclear Information System (INIS)

    Popescu, V.

    1977-01-01

    In view of producing heavy water, the influence of the deuterium proportion in the basic substances, on the efficiency of the isotope exchange process H 2 S - H 2 O for two temperatures was studied. Heavy water is extracted from ordinary water and concentrated from 0.014 per cent to 5-15 per cent D 2 O by isotope bithermal exchange with the hydrogen sulphite. Theoretical and experimental research was carried out in laboratories and then applied on a pilot plant by designing and testing a drying equipment for hydrogen sulphite. The maximum H 2 S concentration rose to 99.84 per cent. The purity of the hydrogen sulphite resulting from the pilot plant, as well as the optimization of the installation for producing H 2 S depending on the deuterium distribution, make sure that the two methods for the preparation of sodium sulphite and hydrogen sulphite can be applied in industry. (author)

  7. (S-2-(4-Chlorobenzoyl-1,2,3,4-tetrahydrobenzo[e]pyrazino[1,2-a][1,4]diazepine-6,12(11H,12aH-dione—Synthesis and Crystallographic Studies

    Directory of Open Access Journals (Sweden)

    Adam Mieczkowski

    2017-10-01

    Full Text Available (S-2-(4-Chlorobenzoyl-1,2,3,4-tetrahydrobenzo[e]pyrazino[1,2-a][1,4]diazepine-6,12(11H,12aH-dione was obtained in a three-step, one-pot synthesis, starting from optically pure (S-2-piperazine carboxylic acid dihydrochloride. Selective acylation of the β-nitrogen atom followed by condensation with isatoic anhydride and cyclization with HATU/DIPEA to a seven-member benzodiazepine ring, led to the tricyclic benzodiazepine derivative. Crystallographic studies and initial biological screening were performed for the title compound.

  8. Aminosilanes derived from 1H-benzimidazole-2(3H)-thione

    International Nuclear Information System (INIS)

    Palomo-Molina, Juliana; García-Báez, Efrén V.; Contreras, Rosalinda; Pineda-Urbina, Kayim; Ramos-Organillo, Angel

    2015-01-01

    In two trimethylsilyl-substituted 1H-benzimidazole-2(3H)-thiones, noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe 3 groups form helicoidal arrangements in one, and dimerization results in the formation of R s 2 (8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings, in the second compound. Two new molecular structures, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, C 13 H 22 N 2 SSi 2 , (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, C 10 H 14 N 2 SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe 3 groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R 2 2 (8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings

  9. Raman enhancement effect on two-dimensional layered materials: graphene, h-BN and MoS2.

    Science.gov (United States)

    Ling, Xi; Fang, Wenjing; Lee, Yi-Hsien; Araujo, Paulo T; Zhang, Xu; Rodriguez-Nieva, Joaquin F; Lin, Yuxuan; Zhang, Jin; Kong, Jing; Dresselhaus, Mildred S

    2014-06-11

    Realizing Raman enhancement on a flat surface has become increasingly attractive after the discovery of graphene-enhanced Raman scattering (GERS). Two-dimensional (2D) layered materials, exhibiting a flat surface without dangling bonds, were thought to be strong candidates for both fundamental studies of this Raman enhancement effect and its extension to meet practical applications requirements. Here, we study the Raman enhancement effect on graphene, hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS2), by using the copper phthalocyanine (CuPc) molecule as a probe. This molecule can sit on these layered materials in a face-on configuration. However, it is found that the Raman enhancement effect, which is observable on graphene, hBN, and MoS2, has different enhancement factors for the different vibrational modes of CuPc, depending strongly on the surfaces. Higher-frequency phonon modes of CuPc (such as those at 1342, 1452, 1531 cm(-1)) are enhanced more strongly on graphene than that on h-BN, while the lower frequency phonon modes of CuPc (such as those at 682, 749, 1142, 1185 cm(-1)) are enhanced more strongly on h-BN than that on graphene. MoS2 demonstrated the weakest Raman enhancement effect as a substrate among these three 2D materials. These differences are attributed to the different enhancement mechanisms related to the different electronic properties and chemical bonds exhibited by the three substrates: (1) graphene is zero-gap semiconductor and has a nonpolar C-C bond, which induces charge transfer (2) h-BN is insulating and has a strong B-N bond, while (3) MoS2 is semiconducting with the sulfur atoms on the surface and has a polar covalent bond (Mo-S) with the polarity in the vertical direction to the surface. Therefore, the different Raman enhancement mechanisms differ for each material: (1) charge transfer may occur for graphene; (2) strong dipole-dipole coupling may occur for h-BN, and (3) both charge transfer and dipole-dipole coupling may

  10. OH+ Formation in the Low-temperature O+(4S) + H2 Reaction

    Science.gov (United States)

    Kovalenko, Artem; Dung Tran, Thuy; Rednyk, Serhiy; Roučka, Štěpán; Dohnal, Petr; Plašil, Radek; Gerlich, Dieter; Glosík, Juraj

    2018-04-01

    Formation of OH+ in collisions of ground-state O+(4S) ions with normal H2 has been studied using a variable temperature 22-pole RF ion trap. From 300 to 30 K the measured reaction rate coefficient is temperature-independent, with a small decrease toward 15 K. The recent wave packet calculation predicts a slightly steeper temperature dependence. The rate coefficients at 300 and 15 K are almost the same, (1.4 ± 0.3) × 10‑9 cm3 s‑1 and (1.3 ± 0.3) × 10‑9 cm3 s‑1, respectively. The influence of traces of the two metastable ions, O+(2D) and O+(2P), has been examined by monitoring the H+ products of their reactions with H2, as well as by chemically probing them with N2 reactant gas.

  11. Efficient degradation of H2S over transition metal modified TiO2 under VUV irradiation: Performance and mechanism

    Science.gov (United States)

    Liu, Gaoyuan; Ji, Jian; Hu, Peng; Lin, Sixin; Huang, Haibao

    2018-03-01

    Odor pollution causes great harm to the atmospheric environment and human health. H2S, as an odor gas, is highly toxic and corrosive and thus requires removal efficiently. In this study, TiO2 catalysts modified by transition metals including Mn, Cu, Ni and Co, were prepared using a modified sol-gelatin method and tested under UV-PCO or VUV-PCO process. H2S degradation was great enhanced in VUV-PCO compared with conventional UV-PCO. Among the catalysts, 1 wt% Mn-TiO2 showed the highest removal efficiency of 89.9%, which is 30 times higher than that under 254 nm UV irradiation. Residual ozone in the outlet can be completely eliminated by Mn-TiO2. Photocatalytic oxidation, photolysis and ozone-assisted catalytic oxidation all involved in the VUV-PCO process and their contribution were determined by H2S removal efficiency.

  12. S phase activation of the histone H2B promoter by OCA-S, a coactivator complex that contains GAPDH as a key component.

    Science.gov (United States)

    Zheng, Lei; Roeder, Robert G; Luo, Yan

    2003-07-25

    We have isolated and functionally characterized a multicomponent Oct-1 coactivator, OCA-S which is essential for S phase-dependent histone H2B transcription. The p38 component of OCA-S binds directly to Oct-1, exhibits potent transactivation potential, is selectively recruited to the H2B promoter in S phase, and is essential for S phase-specific H2B transcription in vivo and in vitro. Surprisingly, p38 represents a nuclear form of glyceraldehyde-3-phosphate dehydrogenase, and binding to Oct-1, as well as OCA-S function, is stimulated by NAD(+) but inhibited by NADH. OCA-S also interacts with NPAT, a cyclin E/cdk2 substrate that is broadly involved in histone gene transcription. These studies thus link the H2B transcriptional machinery to cell cycle regulators, and possibly to cellular metabolic state (redox status), and set the stage for studies of the underlying mechanisms and the basis for coordinated histone gene expression and coupling to DNA replication.

  13. The H.E.S.S. data acquisition system

    CERN Document Server

    Balzer, A; Gajdus, M; Göring, D; Lopatin, A; Murach, T; de Naurois, M; Schlenker, S; Schwanke, U; Stegmann, C; Wagner, P

    2014-01-01

    The High Energy Stereoscopic System (H.E.S.S.) is an array of five Imaging Atmospheric Cherenkov Telescopes located in the Khomas Highland in Namibia. It measures cosmic gamma-rays with very high energies (> 100 GeV) using the Earth's atmosphere as a calorimeter. The H.E.S.S. experiment has entered Phase II in September 2012 with the inauguration of a fifth telescope that is larger and more complex than the other four. The very large mirror area of 600 m(2) in comparison to the 100 m(2) of the smaller telescopes results in a lower energy threshold as well as an increased overall sensitivity of the system. Moreover, the huge effective area, due to the large mirror size, is crucial in the detection of short time scale low energy transient events. This paper will give a brief overview of the design principles of the current H.E.S.S. data acquisition and array control system. Particular emphasis is given to the new Target of Opportunity alert system that has recently been introduced to the array and allows the in...

  14. Aminosilanes derived from 1H-benzimidazole-2(3H)-thione

    Energy Technology Data Exchange (ETDEWEB)

    Palomo-Molina, Juliana [Facultad de Ciencias Químicas, Universidad de Colima, Carretera Coquimatlán-Colima, Coquimatlán Colima 28400 (Mexico); García-Báez, Efrén V. [Unidad Profesional Interdisciplinaria de Biotecnología, Instituto Politécnico Nacional, Avenida Acueducto s/n, Barrio La Laguna Ticomán, México DF 07340 (Mexico); Contreras, Rosalinda [Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México DF 07000 (Mexico); Barrio La Laguna Ticomán, México DF 07340 (Mexico); Pineda-Urbina, Kayim; Ramos-Organillo, Angel, E-mail: aaramos@ucol.mx [Facultad de Ciencias Químicas, Universidad de Colima, Carretera Coquimatlán-Colima, Coquimatlán Colima 28400 (Mexico)

    2015-08-12

    In two trimethylsilyl-substituted 1H-benzimidazole-2(3H)-thiones, noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe{sub 3} groups form helicoidal arrangements in one, and dimerization results in the formation of R{sub s} {sup 2}(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings, in the second compound. Two new molecular structures, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, C{sub 13}H{sub 22}N{sub 2}SSi{sub 2}, (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, C{sub 10}H{sub 14}N{sub 2}SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe{sub 3} groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R{sub 2}{sup 2}(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings.

  15. Nutrición y Dietética como optativa para 4º de la ESO como medida de concienciación del alumnado sobre hábitos saludables, salud y obesidad

    OpenAIRE

    Delgado, Laura

    2012-01-01

    Este proyecto presenta la programación de una asignatura con la intención de suscitar interés y mejorar los conocimientos del alumnado en temas relacionados con la alimentación, la nutrición y la dietética y concienciarse de la situación actual de obesidad existente en su entorno, tomar medidas fundamentales en cuanto a hábitos sanos y saludables, tanto de alimentación como de ejercicio físico, para así poder frenar esta enfermedad tan grave, que cada vez afecta más a los jóven...

  16. Simultaneous mass transfer of H2S and CO2 with complex chemical reactions in an aqueous di-isopropanolamine solution = Gleichzeitige absorption von H2S und CO2 in Wässriger Di-isopropanolaminlösung

    NARCIS (Netherlands)

    Blauwhoff, P.M.M.; van Swaaij, Willibrordus Petrus Maria

    1985-01-01

    The absorption of H2S and CO2 into an aqueous di-isopropanolamine (DIPA) solution was studied experimentally and theoretically as an example of simultaneous mass transfer with complex reversible reactions. The absorption phenomena were classified into three regimes: (1) negligible mutual interaction

  17. Effects of onion extract on endogenous vascular H2S and adrenomedulin in rat atherosclerosis.

    Science.gov (United States)

    Li, Wei; Tang, Chaoshu; Jin, Hongfang; Du, Junbao

    2011-09-01

    This study aimed to explore the effect of onion extract on endogenous hydrogen sulfide (H2S) and adrenomedulin (ADM) and on atherosclerotic progression in rats with atherosclerosis (AS). Male Sprague-Dawley rats were randomly divided into control, AS and AS+onion groups. Ultrastructure of aorta and atherosclerotic lesions both in aorta and in coronary artery were detected. Plasma and aortic H2S were detected by using a sulfide- sensitive electrode. Plasma and aortic ADM was determined with radioimmunoassay. Cystathionine-γ-lyase (CSE), calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein (RAMP1, RAMP2 and RAMP3) mRNA expressions were analysed. Glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and NO synthase (NOS) contents in plasma, SOD1, SOD2 and ICAM-1 expressions in aorta were detected. Rats in the AS group showed marked atherosclerotic lesions both in aorta and in coronary artery but decreased aortic H2S production. Decreased plasma and aortic ADM content, but increased levels of aortic CRLR, RAMP2 and RAMP3 mRNAs were observed. Plasma GSH-PX and SOD were reduced but MDA elevated. Plasma ICAM-1 and NO contents and iNOS activity were increased. Onion extract, however, lessened atherosclerotic lesions and increased endogenous aortic H2S production, but decreased plasma ADM content, aortic ADM content and aortic CRLR, RAMP2 and RAMP3 mRNAs. In addition, it increased plasma GSH-PX level and SOD activities but reduced MDA; it decreased inflammatory response but increased plasma eNOS activity and NO content. Onion extract exerted a marked antiatherogenic effect in association with the up-regulation of the endogenous CSE/H2S pathway but down-regulation of the ADM/CRLR family in atherosclerotic rats.

  18. La utilidad como satisfacción de sí

    Directory of Open Access Journals (Sweden)

    Ángel Emilio Muñoz Cardona

    2008-04-01

    Full Text Available El fin del presente ensayo es mostrar cómo debería ser entendido hoy el término utilitarismo desde la economía política y desde la filosofía moral. Generalmente se asocia el término utilitario a una persona o a una acción política o social con una calificación despectiva, que da a entender una posición altamente egoísta de utilización fría y calculadora. Lo que no debería de ser así, ya que el fin que perseguían los filósofos y economistas del siglo XVIII como: Francis Hutcheson, Adam Smith, Jeremy Bentham y John Stuart Mill fue la de ilustrar cuál es la importancia social de buscar en cada una de las acciones particulares el bienestar general. Es decir, encontrar la mejor manera de mostrar el mal que representa tanto para sí mismo como para la construcción de una sociedad prospera y pujante el egoísmo (selfishness. Por lo tanto, el utilitarismo debería ser visto y entendido como la preocupación filosófica y de la economía política más importante (desde el siglo XVIII hasta nuestros días en la búsqueda por el bienestar social como un todo. En otras palabras, lo bueno que por naturaleza significa para el hombre la satisfacción en el cuidado de su yo social, en su self love.

  19. Determination of structural, thermodynamic and phase properties in the Na2S-H2O system for application in a chemical heat pump

    International Nuclear Information System (INIS)

    Boer, R. de; Haije, W.G.; Veldhuis, J.B.J.

    2002-01-01

    Structural, thermodynamic and phase properties in the Na 2 S-H 2 O system for application in a chemical heat pump have been investigated using XRD, TG/DTA and melting point and vapour pressure determinations. Apart from the known crystalline phases Na 2 S·9H 2 O, Na 2 S·5H 2 O and Na 2 S a new phase Na 22H 2 O has been proven to exist. Na 2 S·((1)/(2))H 2 O is not a phase but a 3:1 mixture of Na 2 S and Na 22H 2 O, presumably stabilised by very slow dehydration kinetics. The vapour pressure-temperature equilibria of the sodium sulphide hydrates have been determined and a consistent set of thermodynamic functions for these compounds has been derived. XRD measurements indicate the topotactic character of the transitions between the hydration states

  20. H2S AND NO SIGNALING INTERACTIONS IN THALE CRESS (ARABIDOPSIS THALIANA L. AND PEPPER (CAPSICUM ANNUUM L. LEAVES

    Directory of Open Access Journals (Sweden)

    Miroslav Lisjak

    2012-06-01

    Full Text Available This research comprehends a set of experiments with several thale cress (Arabidopsis thaliana L. and pepper (Capsicum annuum L. genotypes in controlled conditions using growth chambers, with the aim of determining the physiological role of hydrogen sulfide (H2S in plants, as well as its potential effect as a signaling compound, particularly in potential interaction with nitric oxide (NO signaling pathways. Special emphasis was focused on stomatal mechanisms and signaling in their opening and closing. Moreover, the effect of treatment of pepper plants with H2S was investigated in salt stress conditions. It was established that the applied H2S donors, NaHS and GYY4137, inhibit stomata closing in both plant species through the reduction of NO accumulation in stomata, which was proven to occur in SNP or ABA treatment. The effects of NO and H2S were opposite those in pepper plants response to salt stress as well, with increased antioxidative activity in leaf obtained after H2S treatments, and with NaHS in particular. In addition, GYY4137 could be considered as a convenient H2S donor for research into H2S functions in plants. The results point out the interactions of H2S and NO in plant cell signaling in both normal and salt stress conditions. Further research of this type should uncover H2S functions in plant metabolism more precisely, especially considering the potential practical value of this knowledge for plant stress resistance improvement and their productivity enhancement.

  1. Low-Frequency Noise in Layered ReS2 Field Effect Transistors on HfO2 and Its Application for pH Sensing.

    Science.gov (United States)

    Liao, Wugang; Wei, Wei; Tong, Yu; Chim, Wai Kin; Zhu, Chunxiang

    2018-02-28

    Layered rhenium disulfide (ReS 2 ) field effect transistors (FETs), with thickness ranging from few to dozens of layers, are demonstrated on 20 nm thick HfO 2 /Si substrates. A small threshold voltage of -0.25 V, high on/off current ratio of up to ∼10 7 , small subthreshold swing of 116 mV/dec, and electron carrier mobility of 6.02 cm 2 /V·s are obtained for the two-layer ReS 2 FETs. Low-frequency noise characteristics in ReS 2 FETs are analyzed for the first time, and it is found that the carrier number fluctuation mechanism well describes the flicker (1/f) noise of ReS 2 FETs with different thicknesses. pH sensing using a two-layer ReS 2 FET with HfO 2 as a sensing oxide is then demonstrated with a voltage sensitivity of 54.8 mV/pH and a current sensitivity of 126. The noise characteristics of the ReS 2 FET-based pH sensors are also examined, and a corresponding detection limit of 0.0132 pH is obtained. Our studies suggest the high potential of ReS 2 for future low-power nanoelectronics and biosensor applications.

  2. Obtention of agricultural gypsum traced on {sup 34} S (Ca{sup 34} SO{sub 4}.2H{sub 2}O), by chemical reaction between H{sub 2}{sup 34} SO{sub 4} and Ca(OH){sub 2}; Obtencao do gesso agricola marcado no {sup 34} S (Ca{sup 34} SO{sub 4}.2H{sub 2}O), por reacao quimica entre o H{sub 2}{sup 34} SO{sub 4} e Ca(OH){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rossete, Alessandra L.R.M.; Bendassolli, Jose A.; Ignoto, Raquel de Fatima; Batagello, Hugo Henrique [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis

    2002-07-01

    The gypsum (CaSO{sub 4}.2H{sub 2}O) has double function in the soil: as source of calcium and sulfur and reducing agent of aluminum saturation. The sulfur for the plants has acting in the vital functions and it is proven fact increase of the S deficiency in Brazilian soils. The isotope tracer {sup 34} S can elucidate important aspects in the sulfur cycle. The Ca{sup 34} SO{sub 4}.2H{sub 2}O was obtained by chemical reaction between Ca(OH){sub 2} and H{sub 2}{sup 34} SO{sub 4} solution. The acid was obtained by chromatography ionic change, using cationic resin Dowex 50WX8 and Na{sub 2}{sup 34} SO{sub 4} solution. The reaction was realized under slow agitation. After the reaction, the precipitate was separated and dried in ventilated stove at 60 deg C temperature. The Mass of the Ca{sup 34} SO{sub 4}.2H{sub 2}O produced was determined by method gravimetric. This way, a system contends resin 426 cm{sup 3}, considering volume of 2.2 liters can be obtained a solution contends 44.2 g of H{sub 2}{sup 34} SO{sub 4}, theoretically could be produced 78.0 g of Ca{sup 34} SO{sub 4}.2H{sub 2}O approximately. With results of the tests were verified that there was not total precipitation of the Ca{sup 34}SO{sub 4}.2H{sub 2}O. Were produced 73.7{+-} 0.6 g of Ca{sup 34} SO{sub 4}.2H{sub 2}O representing average income 94.6{+-}0.8 %. The purity of the produced CaSO{sub 4}.2H{sub 2}O was 98%. (author)

  3. Redução da emissão de CO2, CH4 e H2S através da compostagem de dejetos suínos Reduction emissions of CO2, CH4 and H2S through composting of swine manure

    Directory of Open Access Journals (Sweden)

    Luana G. Sardá

    2010-09-01

    Full Text Available Em conjunto com o crescente desenvolvimento da tecnologia para a produção de suínos ocorreu uma forte exploração e degradação do ambiente, razão pela qual a atividade se transformou em fonte poluidora das regiões produtoras. Buscam-se, então, alternativas que minimizem o potencial poluidor do atual sistema de produção. O trabalho proposto foi comparar o perfil de emissão de dióxido de carbono (CO2, metano (CH4 e gás sulfídrico (H2S do manejo de dejetos suínos nas formas sólida (compostagem e líquida (esterqueira, e avaliar a eficiência do processo de compostagem através dos parâmetros físico-químicos. O ensaio foi implantado no campo experimental da EMBRAPA Suínos e Aves, localizada no município de Concórdia, SC. Contatou-se, na compostagem, uma redução de 7 vezes na emissão de CH4, com relação à esterqueira; a emissão de CO2 representou 78,5% do carbono total mineralizado. Considerando-se que a emissão de H2S foi expressiva apenas no manejo dos dejetos na forma líquida, pode-se afirmar que o manejo dos resíduos na forma sólida é uma alternativa para a redução dos impactos ambientais pela mitigação do efeito estufa e pela redução de odores.In conjunction with the development of technologies for the production of swine meat, a strong exploration and degradation of the environment occurred and the activity became a source of pollution in the producing regions. Therefore, there is a need for alternative technologies that minimize the pollutant potential of the current system of production. The proposed work was to analyze and to compare the emission of carbon dioxide (CO2, methane (CH4 and hydrogen sulfide (H2S between the management of swine manure in solid form (composting and liquid manure (deep pit, and assess the efficiency of the process of composting through the physical and chemical parameters. The test was implemented in the experimental field of Embrapa Suínos e Aves, located in Concordia (SC

  4. Preparation of ZnO/SiO{sub 2} gel composites and their performance of H{sub 2}S removal at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guoqiang [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Huang, Zheng-Hong, E-mail: zhhuang@tsinghua.edu.cn [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kang, Feiyu [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Institute of Advanced Materials Research, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2012-05-15

    Graphical abstract: The ZnO/SiO{sub 2} gel composites exhibit mixed type isotherms, in which the initial part is type I, and intermediate and high relative pressures are type IV with a hysteresis loop of type H2. The breakthrough time of ZnO/SiO{sub 2} composites first increased sharply up to 400 Degree-Sign C with the H{sub 2}S breakthrough capacity is up to 96.4 mg/g, and then decrease dramatically with further rising of temperature beyond 500 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer High surface area ZnO/SiO{sub 2} gel composites were prepared by co-sol-gel method. Black-Right-Pointing-Pointer The active phase (ZnO) well disperses in the composites. Black-Right-Pointing-Pointer The highest H{sub 2}S adsorption capacity of the composites reaches up to 96.4 mg/g. Black-Right-Pointing-Pointer Both physisorption and the active phase reactivation governed the H{sub 2}S removal process. - Abstract: ZnO/SiO{sub 2} gel composites with different active component loading were prepared by sol-gel method combined with ambient drying process, followed by thermal treatment. The gel composites were characterized by scanning electron microscopy (SEM), nitrogen adsorption, X-ray diffraction (XRD), FTIR and X-ray photoelectron spectroscopy (XPS), and their performances for H{sub 2}S removal were evaluated by dynamic testing at room temperature. The as prepared materials exhibited high surface area with multimodal pore size distributions in micropore and mesopore region. The porous properties were significantly influenced both by the ZnO loading ratio and the treated temperature. The gel composites showed a high performance for H{sub 2}S removal, with the highest H{sub 2}S adsorption capacity of 96.4 mg/g for the sample treated at 400 Degree-Sign C with 30 wt% ZnO. Both physisorption and the active phase reactivation governed the H{sub 2}S removal process. It needs to optimize the composites' porous structure and active component loading amount.

  5. [Analysis of H2S/PH3/NH3/AsH3/Cl2 by Full-Spectral Flame Photometric Detector].

    Science.gov (United States)

    Ding, Zhi-jun; Wang, Pu-hong; Li, Zhi-jun; Du, Bin; Guo, Lei; Yu, Jian-hua

    2015-07-01

    Flame photometric analysis technology has been proven to be a rapid and sensitive method for sulfur and phosphorus detection. It has been widely used in environmental inspections, pesticide detection, industrial and agricultural production. By improving the design of the traditional flame photometric detector, using grating and CCD sensor array as a photoelectric conversion device, the types of compounds that can be detected were expanded. Instead of a single point of characteristic spectral lines, full spectral information has been used for qualitative and quantitative analysis of H2S, PH3, NH3, AsH3 and Cl2. Combined with chemometric method, flame photometric analysis technology is expected to become an alternative fast, real-time on-site detection technology to simultaneously detect multiple toxic and harmful gases.

  6. Pegada Hídrica como Indicador de Sustentabilidade Ambiental1

    Directory of Open Access Journals (Sweden)

    Kettrin Farias Bem Maracajá

    2012-08-01

    Full Text Available O conceito de pegada hídrica tem sido recentemente introduzido como um importante indicador do consumo de água humano, na tentativa de minimizar os impactos ambientais. Esse trabalho aborda o conceito da pegada hídrica como um indicador de sustentabilidade, com vistas o uso racional dos recursos hídricos. Nos últimos anos, a escassez de alguns recursos naturais vem sendo bastante discutido em todo o mundo e quanto à água a preocupação é ainda maior em face do uso desordenado na irrigação, bem como pela poluição da água potável através da indústria e agricultura. Partindo dessa análise, a pegada hídrica surge como um indicador de sustentabilidade da água doce em seus diferentes tipos de consumo para que seja utilizada de forma consciente. Com base na revisão da literatura sobre o tema abordado, conclui-se que para a redução da pegada hídrica se deve tomar medidas de controle do uso direto e indireto da água doce principalmente na agricultura irrigada.

  7. The Formation and Spatiotemporal Progress of the pH Wave Induced by the Temperature Gradient in the Thin-Layer H2O2-Na2S2O3-H2SO4-CuSO4 Dynamical System.

    Science.gov (United States)

    Jędrusiak, Mikołaj; Orlik, Marek

    2016-03-31

    The H2O2-S2O3(2-)-H(+)-Cu(2+) dynamical system exhibits sustained oscillations under flow conditions but reveals only a single initial peak of the indicator electrode potential and pH variation under batch isothermal conditions. Thus, in the latter case, there is no possibility of the coupling of the oscillations and diffusion which could lead to formation of sustained spatiotemporal patterns in this process. However, in the inhomogeneous temperature field, due to dependence of the local reaction kinetics on temperature, spatial inhomogeneities of pH distribution can develop which, in the presence of an appropriate indicator, thymol blue, manifest themselves as the color front traveling along the quasi-one-dimensional reactor. In this work, we describe the experimental conditions under which the above-mentioned phenomena can be observed and present their numerical model based on thermokinetic coupling and spatial coordinate introduced to earlier isothermal homogeneous kinetic mechanism.

  8. Theoretical insight into the effect of collision energy on the S(3P) + SH( X 2∏) → S2( X 3∑g -) + H(2S) reaction

    Science.gov (United States)

    Shoubao, Gao; Guomeng, Chen; Yuzhi, Song; Qingtian, Meng; Qing, Xu

    2018-01-01

    In this work, the dynamics of reaction S(3P) + SH( X 2∏) → S2( X 3∑g -) + H(2S) has been investigated using quasi-classical trajectories method on a newly constructed accurate double many-body expansion potential energy surface of Song et al. [J. Phys. Chem. A 115, 5274 (2011)]. The integral cross section and the rate constant are obtained. Furthermore, the distribution reflecting vector correlation and the polarization-dependent differential cross section are investigated. The results show a decreasing behavior of the integral cross section as the increasing of the collision energy, and dominate complex forming mechanism at lower energies, as well as the stripping mechanism at higher energies. Those results indicate that the product S2 is sensitively affected by the collision energy.

  9. Synthesis and characterization of new N-(diphenylphosphino)-naphthylamine chalcogenides: X-ray structures of (1-NHC 10H 7)P(Se)Ph 2 and Ph 2P(S)OP(S)Ph 2

    KAUST Repository

    Tomah Al-Masri, Harbi; Emwas, Abdul-Hamid M.; Al-Talla, Zeyad; Al Kordi, Mohamed

    2012-01-01

    The reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC 10H 7)PPh 2 (1) ligand. Refluxing of 1 with elemental sulfur or grey selenium in toluene (1:1 molar ratio) afforded (1-NHC 10H 7)P(S)Ph 2 (2) and (1-NHC 10H 7)P(Se)Ph 2 (3), respectively. Moreover, the byproduct {Ph 2P(S)} 2O (4) was isolated from the reaction of 1 with elemental sulfur. Compounds 1-3 were identified and characterized by multinuclear ( 1H, 13C, 31P, 77Se) NMR spectroscopy, mass spectrometry, and elemental analysis. Crystal structure determinations of 3 and 4 were carried out. Copyright © 2012 Taylor and Francis Group, LLC.

  10. Synthesis and characterization of new N-(diphenylphosphino)-naphthylamine chalcogenides: X-ray structures of (1-NHC 10H 7)P(Se)Ph 2 and Ph 2P(S)OP(S)Ph 2

    KAUST Repository

    Tomah Al-Masri, Harbi

    2012-09-01

    The reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC 10H 7)PPh 2 (1) ligand. Refluxing of 1 with elemental sulfur or grey selenium in toluene (1:1 molar ratio) afforded (1-NHC 10H 7)P(S)Ph 2 (2) and (1-NHC 10H 7)P(Se)Ph 2 (3), respectively. Moreover, the byproduct {Ph 2P(S)} 2O (4) was isolated from the reaction of 1 with elemental sulfur. Compounds 1-3 were identified and characterized by multinuclear ( 1H, 13C, 31P, 77Se) NMR spectroscopy, mass spectrometry, and elemental analysis. Crystal structure determinations of 3 and 4 were carried out. Copyright © 2012 Taylor and Francis Group, LLC.

  11. An Exploratory Flow Reactor Study of H2S Oxidation at 30-100 Bar

    DEFF Research Database (Denmark)

    Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt

    2016-01-01

    Hydrogen sulfide oxidation experiments were conducted in O2/N2 at high pressure (30 and 100 bar) under oxidizing and stoichiometric conditions. Temperatures ranged from 450 to 925 K, with residence times of 3–20 s. Under stoichiometric conditions, the oxidation of H2S was initiated at 600 K...

  12. Augmented H2S production via cystathionine-beta-synthase upregulation plays a role in pregnancy-associated uterine vasodilation.

    Science.gov (United States)

    Sheibani, Lili; Lechuga, Thomas J; Zhang, Honghai; Hameed, Afshan; Wing, Deborah A; Kumar, Sathish; Rosenfeld, Charles R; Chen, Dong-Bao

    2017-03-01

    Endogenous hydrogen sulfide (H2S) synthesized via metabolizing L-cysteine by cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) is a potent vasodilator and angiogenic factor. The objectives of this study were to determine if human uterine artery (UA) H2S production increases with augmented expression and/or activity of CBS and/or CSE during the menstrual cycle and pregnancy and whether exogenous H2S dilates UA. Uterine arteries from nonpregnant (NP) premenopausal proliferative (pPRM) and secretory (sPRM) phases of the menstrual cycle and pregnant (P) women were studied. H2S production was measured by the methylene blue assay. CBS and CSE mRNAs were assessed by quantitative real-time PCR, and proteins were assessed by immunoblotting and semiquantitative immunofluorescence microscopy. Effects of H2S on rat UA relaxation were determined by wire myography ex vivo. H2S production was greater in NP pPRM and P than NP sPRM UAs and inhibited by the specific CBS but not CSE inhibitor. CBS but not CSE mRNA and protein were greater in NP pPRM and P than NP sPRM UAs. CBS protein was localized to endothelium and smooth muscle and its levels were in a quantitative order of P >NP UAs of pPRM>sPRM. CSE protein was localized in UA endothelium and smooth muscle with no difference among groups. A H2S donor relaxed P > NP UAs but not mesentery artery. Thus, human UA H2S production is augmented with endothelium and smooth muscle CBS upregulation, contributing to UA vasodilation in the estrogen-dominant physiological states in the proliferative phase of the menstrual cycle and pregnancy. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Molecular treatment of the ion-pair formation reaction in H(1s) + H(1s) collisions

    Energy Technology Data Exchange (ETDEWEB)

    Borondo, F.; Martin, F.; Yaez, M.

    1987-01-01

    All the available theoretical calculations of the cross section for the ion-pair formation reaction H(1s)+H(1s)..-->..H/sup +/H/sup -/(1s/sup 2/) have been performed using methods that are only valid at high collision energies. They get good agreement with the experiments for impact energies greater than 25 keV, but fail completely at smaller energies. In this work we report the cross section for this reaction at impact energies less than 10 keV, calculated in the framework of the impact-parameter approximation and using the molecular method with a common translation factor.

  14. Molecular treatment of the ion-pair formation reaction in H(1s) + H(1s) collisions

    International Nuclear Information System (INIS)

    Borondo, F.; Martin, F.; Yaez, M.

    1987-01-01

    All the available theoretical calculations of the cross section for the ion-pair formation reaction H(1s)+H(1s)→H + H - (1s 2 ) have been performed using methods that are only valid at high collision energies. They get good agreement with the experiments for impact energies greater than 25 keV, but fail completely at smaller energies. In this work we report the cross section for this reaction at impact energies less than 10 keV, calculated in the framework of the impact-parameter approximation and using the molecular method with a common translation factor

  15. H2S and volatile fatty acids elimination by biofiltration: clean-up process for biogas potential use.

    Science.gov (United States)

    Ramírez-Sáenz, D; Zarate-Segura, P B; Guerrero-Barajas, C; García-Peña, E I

    2009-04-30

    In the present work, the main objective was to evaluate a biofiltration system for removing hydrogen sulfide (H(2)S) and volatile fatty acids (VFAs) contained in a gaseous stream from an anaerobic digestor (AD). The elimination of these compounds allowed the potential use of biogas while maintaining the methane (CH(4)) content throughout the process. The biodegradation of H(2)S was determined in the lava rock biofilter under two different empty bed residence times (EBRT). Inlet loadings lower than 200 g/m(3)h at an EBRT of 81 s yielded a complete removal, attaining an elimination capacity (EC) of 142 g/m(3)h, whereas at an EBRT of 31 s, a critical EC of 200 g/m(3)h was reached and the EC obtained exhibited a maximum value of 232 g/m(3)h. For 1500 ppmv of H(2)S, 99% removal was maintained during 90 days and complete biodegradation of VFAs was observed. A recovery of 60% as sulfate was obtained due to the constant excess of O(2) concentration in the system. Acetic and propionic acids as a sole source of carbon were also evaluated in the bioreactor at different inlet loadings (0-120 g/m(3)h) obtaining a complete removal (99%) for both. Microcosms biodegradation experiments conducted with VFAs demonstrated that acetic acid provided the highest biodegradation rate.

  16. Synthesis of ZnO nanorods by spray pyrolysis for H2S gas sensor

    International Nuclear Information System (INIS)

    Shinde, S.D.; Patil, G.E.; Kajale, D.D.; Gaikwad, V.B.; Jain, G.H.

    2012-01-01

    Highlights: ► Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique. ► ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H 2 S gas (100 ppm) at 50 °C. ► This ZnO thin film has potential in application of room temperature H 2 S gas sensing. - Abstract: Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique (SPT). The equal amount of methanol and water is used as a solvent to dissolve the AR grade Zinc acetate for precursor solution. This solution is sprayed on to the glass substrate heated at 350 °C. The films were characterized by ultra-violet spectroscopy (UV), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The deposition of thin films results in a layer comprising well-shaped hexagonal ZnO nanorods with diameter of 90–120 nm and length of up to 200 nm. The gas sensing properties of these films have been investigated for various interfering gases such as CO 2 , CO, ethanol, NH 3 and H 2 S, etc. at operating temperature from 30° (room temperature) to 450 °C. The results indicate that the ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H 2 S gas (100 ppm) at 50 °C. The hexagonal pillar shaped ZnO nanorods can improve the sensitivity and selectivity of the sensors.

  17. H-point exciton transitions in bulk MoS2

    International Nuclear Information System (INIS)

    Saigal, Nihit; Ghosh, Sandip

    2015-01-01

    Reflectance and photoreflectance spectrum of bulk MoS 2 around its direct bandgap energy have been measured at 12 K. Apart from spectral features due to the A and B ground state exciton transitions at the K-point of the Brillouin zone, one observes additional features at nearby energies. Through lineshape analysis the character of two prominent additional features are shown to be quite different from that of A and B. By comparing with reported electronic band structure calculations, these two additional features are identified as ground state exciton transitions at the H-point of the Brillouin zone involving two spin-orbit split valance bands. The excitonic energy gap at the H-point is 1.965 eV with a valance bands splitting of 185 meV. While at the K-point, the corresponding values are 1.920 eV and 205 meV, respectively

  18. Electron capture and excitation in collisions of O+(4S,2D,2P) with H2 molecules

    International Nuclear Information System (INIS)

    Pichl, Lukas; Li Yan; Liebermann, Heinz-Peter; Buenker, Robert J.; Kimura, Mineo

    2004-01-01

    Using an electronic-state close-coupling method, we treated the electron capture and excitation processes of O + ions both in ground state O + ( 4 S) and metastable states O +* ( 2 D) and O +* ( 2 P) in collisions with the H 2 molecule. In the ground-state projectile energy region considered (from 50 eV/amu to 10 keV/amu), the experimental data vary by orders of magnitude: our results smoothly connect to the data by Flesch and Ng [J. Chem. Phys. 94, 2372 (1991)] and Xu et al. [J. Phys. B 23, 1235 (1990)] at low energy and agree with Phaneuf et al. [Phys. Rev. A 17, 534 (1978)] in the high-energy region. The present values differ from Sieglaff et al. [Phys. Rev. A 59, 3538 (1999)] and Nutt et al. [J. Phys. B 12, L157 (1979)], especially in the energy region below 1 keV/amu. We provide the first calculated state-resolved cross sections of electron capture and target-projectile electronic excitations for the O + ( 4 S, 2 D, 2 P)-H 2 collision system

  19. Construction of global ab initio potential energy surfaces for the HNS system and quantum dynamics calculations for the S({sup 3}P) + NH(X{sup 3}Σ) → NS(X{sup 2}Π) + H({sup 2}S) and N({sup 4}S) + SH(X{sup 2}Π) → NS(X{sup 2}Π) + H({sup 2}S) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kazuma; Takayanagi, Toshiyuki, E-mail: tako@mail.saitama-u.ac.jp

    2014-08-17

    Highlights: • Low-lying three potential energy surfaces for the HNS/HSN system are developed. • Quantum scattering calculations are performed for S + NH and N + SH reactions. • NS production mechanisms from S + NH and N + SH reactions are discussed. - Abstract: The lowest three adiabatic potential energy surfaces (1{sup 1}A′, 1{sup 1}A″ and 1{sup 3}A″) of the HNS molecular system have been developed using ab initio MRCI + Q-level electronic structure calculations with a complete-basis-set approach in order to understand the NS production mechanisms from the S({sup 3}P) + NH(X{sup 3}Σ) → NS(X{sup 2}Π) + H({sup 2}S) and N({sup 4}S) + SH(X{sup 2}Π) → NS(X{sup 2}Π) + H({sup 2}S) reactions. The results of time-independent quantum reactive scattering calculations show that the reactions proceed with the contribution of both direct and HNS/HSN complex-forming mechanisms on all the three potential energy surfaces. It is found that the reaction dynamics is not entirely statistical and cannot be described with a simple capture theory despite that the reactions are barrierless with large exoergicity.

  20. Hydrogen sulfide (H{sub 2}S)/cystathionine γ-lyase (CSE) pathway contributes to the proliferation of hepatoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yan; Ye, Shuang; Yuan, Dexiao; Zhang, Jianghong; Bai, Yang; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2014-05-15

    Highlights: • Inhibition of H{sub 2}S/CSE pathway strongly stimulates cellular apoptosis. • Inhibition of H{sub 2}S/CSE pathway suppresses cell growth by blocking EGFR pathway. • H{sub 2}S/CSE pathway is critical for maintaining the proliferation of hepatoma cells. - Abstract: Hydrogen sulfide (H{sub 2}S)/cystathionine γ-lyase (CSE) pathway has been demonstrated to play vital roles in physiology and pathophysiology. However, its role in tumor cell proliferation remains largely unclear. Here we found that CSE over-expressed in hepatoma HepG2 and PLC/PRF/5 cells. Inhibition of endogenous H{sub 2}S/CSE pathway drastically decreased the proliferation of HepG2 and PLC/PRF/5 cells, and it also enhanced ROS production and mitochondrial disruption, pronounced DNA damage and increased apoptosis. Moreover, this increase of apoptosis was associated with the activation of p53 and p21 accompanied by a decreased ratio of Bcl-2/Bax and up-regulation of phosphorylated c-Jun N-terminal kinase (JNK) and caspase-3 activity. In addition, the negative regulation of cell proliferation by inhibition of H{sub 2}S/CSE system correlated with the blockage of cell mitogenic and survival signal transduction of epidermal growth factor receptor (EGFR) via down-regulating the extracellular-signal-regulated kinase 1/2 (ERK1/2) activation. These results demonstrate that H{sub 2}S/CSE and its downstream pathway contribute to the proliferation of hepatoma cells, and inhibition of this pathway strongly suppress the excessive growth of hepatoma cells by stimulating mitochondrial apoptosis and suppressing cell growth signal transduction.

  1. Estudo da descoloração e degradação de corantes azo mediante processo oxidativo avançado: UV/H2O2

    OpenAIRE

    Adailton Alves

    2009-01-01

    Este estudo teve como objetivo o uso de Processos Oxidativos Avançados (POA\\'s), para a descoloração e degradação dos corantes azo (Congo Red) e (Acid Yellow 42) em solução aquosa, sendo realizado em escala de bancada (processo batelada), utilizando-se reator tubular. Utililizou-se o Processo Oxidativo Avançado UV/H2O2, avaliando a influência dos seguintes fatores: concentração dos corantes, pH, temperatura, concentração do H2O2, concentração do NaCl e concentração do Na2SO4. Para a otimizaçã...

  2. H{sub 2}S Removal in Anaerobic digestion of Sludge by Microaerophilic Processes: Pilot Plant Experience; Eliminacion de H{sub 2}S en digestion anaerobia de lodos por procesos microaerofilico: experiencia en planta piloto

    Energy Technology Data Exchange (ETDEWEB)

    Fdz-Polanco Iniguez de la Torre, M.; Perez Elvira, S. I.; Diaz Villalobos, I.; Garcia Rodriguez, L.; Torio Acha, R.; Acevedo Alvarez, A. F.

    2009-07-01

    Anaerobic digestion of sludge produces a biogas with content in H{sub 2}S between 4.000-6.000 ppm, Removal strategies can operate at three different levels: (1) at the source (source control), (2) at process level or (3) at the end (biogas treatment). Process-level control of sulfide presents several advantages when comparing with traditional biogas treatment. Microaerophilic process consists on the supply of small amounts of oxygen in the digester in order to completely remove H{sub 2}S without affect the anaerobic process. (Author) 9 refs.

  3. Mechanisms of hydrogen sulfide (H2S) action on synaptic transmission at the mouse neuromuscular junction.

    Science.gov (United States)

    Gerasimova, E; Lebedeva, J; Yakovlev, A; Zefirov, A; Giniatullin, R; Sitdikova, G

    2015-09-10

    Hydrogen sulfide (H2S) is a widespread gasotransmitter also known as a powerful neuroprotective agent in the central nervous system. However, the action of H2S in peripheral synapses is much less studied. In the current project we studied the modulatory effects of the H2S donor sodium hydrosulfide (NaHS) on synaptic transmission in the mouse neuromuscular junction using microelectrode technique. Using focal recordings of presynaptic response and evoked transmitter release we have shown that NaHS (300 μM) increased evoked end-plate currents (EPCs) without changes of presynaptic waveforms which indicated the absence of NaHS effects on sodium and potassium currents of motor nerve endings. Using intracellular recordings it was shown that NaHS increased the frequency of miniature end-plate potentials (MEPPs) without changing their amplitudes indicating a pure presynaptic effect. Furthermore, NaHS increased the amplitude of end-plate potentials (EPPs) without influencing the resting membrane potential of muscle fibers. L-cysteine, a substrate of H2S synthesis induced, similar to NaHS, an increase of EPC amplitudes whereas inhibitors of H2S synthesis (β-cyano-L-alanine and aminooxyacetic acid) had the opposite effect. Inhibition of adenylate cyclase using MDL 12,330A hydrochloride (MDL 12,330A) or elevation of cAMP level with 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (pCPT-cAMP) completely prevented the facilitatory action of NaHS indicating involvement of the cAMP signaling cascade. The facilitatory effect of NaHS was significantly diminished when intracellular calcium (Ca(2+)) was buffered by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester (BAPTA-AM) and ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid acetoxymethyl ester (EGTA-AM). Activation of ryanodine receptors by caffeine or ryanodine increased acetylcholine release and prevented further action of NaHS on transmitter release, likely due to

  4. Optimization of operating parameters for gas-phase photocatalytic splitting of H2S by novel vermiculate packed tubular reactor.

    Science.gov (United States)

    Preethi, V; Kanmani, S

    2016-10-01

    Hydrogen production by gas-phase photocatalytic splitting of Hydrogen Sulphide (H2S) was investigated on four semiconductor photocatalysts including CuGa1.6Fe0.4O2, ZnFe2O3, (CdS + ZnS)/Fe2O3 and Ce/TiO2. The CdS and ZnS coated core shell particles (CdS + ZnS)/Fe2O3 shows the highest rate of hydrogen (H2) production under optimized conditions. Packed bed tubular reactor was used to study the performance of prepared photocatalysts. Selection of the best packing material is a key for maximum removal efficiency. Cheap, lightweight and easily adsorbing vermiculate materials were used as a novel packing material and were found to be effective in splitting H2S. Effect of various operating parameters like flow rate, sulphide concentration, catalyst dosage, light irradiation were tested and optimized for maximum H2 conversion of 92% from industrial waste H2S. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Evaluation of H2S sensing characteristics of metals-doped graphene and metals-decorated graphene: Insights from DFT study

    Science.gov (United States)

    Khodadadi, Zahra

    2018-05-01

    The high tendency of graphene to adsorb H2S gas has made it a good choice for the purpose of separating H2S gas from industrial waste streams, and it can also be used as a good H2S sensor. In this research, the adsorption of H2S molecule on pristine, transition metal (Ni, Cu and Zn)-doped graphene and metal-decorated graphene nanosheets have been investigated via first-principles approach based on Density Functional Theory (DFT). The most stable adsorption geometry, rate of adsorption energy and charge transfer of H2S molecule on pristine, metal-doped, and metal-decorated graphene nanosheets have been discussed. The adsorption of H2S gas on several kinds of graphene nanosheets was studied by three different models. As H2S molecule adsorbed on metal-doped graphene nanosheets, we found that the configuration with two hydrogen atoms towards the metal-doped graphene nanosheet as most desirable situation. Moreover, the calculations show that the adsorption energy of H2S on Cu-doped graphene nanosheet is the highest among all the other metal-doped graphene nanosheet systems. We also investigated the H2S capability to bind to Ni, Cu and Zn-decorated graphene nanosheets. It was found that after adsorption, the configuration of the sulfur atom, which was located close to the metal-decorated graphene nanosheets was stable thermodynamically. The Ni-decorated graphene nanosheet with large adsorption energy and short binding distance is suitable for chemisorptions. The unfilled d-shells Ni-decorated graphene nanosheets are primarily responsible for increase in the reactivity.

  6. Achieving simultaneous CO{sub 2} and H{sub 2}S conversion via a coupled solar-driven electrochemical approach on non-precious-metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Weiguang; Yu, Wei; Zong, Xu; Li, Can [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, The Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian (China); Wang, Hong; Wang, Xiaomei; Xu, Zhiqiang [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, The Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian (China); University of Chinese Academy of Sciences, Beijing (China)

    2018-03-19

    Carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S) are generally concomitant with methane (CH{sub 4}) in natural gas and traditionally deemed useless or even harmful. Developing strategies that can simultaneously convert both CO{sub 2} and H{sub 2}S into value-added products is attractive; however it has not received enough attention. A solar-driven electrochemical process is demonstrated using graphene-encapsulated zinc oxide catalyst for CO{sub 2} reduction and graphene catalyst for H{sub 2}S oxidation mediated by EDTA-Fe{sup 2+}/EDTA-Fe{sup 3+} redox couples. The as-prepared solar-driven electrochemical system can realize the simultaneous conversion of CO{sub 2} and H{sub 2}S into carbon monoxide and elemental sulfur at near neutral conditions with high stability and selectivity. This conceptually provides an alternative avenue for the purification of natural gas with added economic and environmental benefits. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Influence of surface properties on the mechanism of H2S removal by alkaline activated carbons.

    Science.gov (United States)

    Yan, Rong; Chin, Terence; Ng, Yuen Ling; Duan, Huiqi; Liang, David Tee; Tay, Joo Hwa

    2004-01-01

    Alkaline activated carbons are widely used as adsorbents of hydrogen sulfide (H2S), one of the major odorous compounds arising from sewage treatment facilities. Although a number of studies have explored the effects of various parameters, mechanisms of H2S adsorption by alkaline carbons are not yet fully understood. The major difficulty seems to lie in the fact that little is known with certainty about the predominant reactions occurring on the carbon surface. In this study, the surface properties of alkaline activated carbons were systematically investigated to further exploit and better understand the mechanisms of H2S adsorption by alkaline activated carbons. Two commercially available alkaline activated carbons and their representative exhausted samples (8 samples collected at different height of the column after H2S breakthrough tests) were studied. The 8 portions of the exhausted carbon were used to represent the H2S/carbon reaction process. The surface properties of both the original and the exhausted carbons were characterized using the sorption of nitrogen (BET test), surface pH, Boehm titration, thermal and FTIR analysis. Porosity and surface area provide detailed information about the pore structure of the exhausted carbons with respect to the reaction extent facilitating the understanding of potential pore blockages. Results of Boehm titration and FTIR both demonstrate the significant effects of surface functional groups, and identification of oxidation products confirmed the different mechanisms involved with the two carbons. From the DTG curves of thermal analysis, two well-defined peaks representing two products of surface reactions (i.e., sulfur and sulfuric acid) were observed from the 8 exhausted portions with gradually changing patterns coinciding with the extent of the reaction. Surface pH values of the exhausted carbons show a clear trend of pH drop along the reaction extent, while pH around 2 was observed for the bottom of the bed indicating

  8. Low levels of H2S may replace sulfate as sulfur source in sulfate-deprived onion

    NARCIS (Netherlands)

    Durenkamp, Mark; De Kok, LJ

    2005-01-01

    Onion (Allium cepa L.) was exposed to low levels of H2S in order to investigate to what extent H2S could be used as a sulfur source for growth under sulfate-deprived conditions. Sulfate deprivation for a two-week period resulted in a decreased biomass production of the shoot, a subsequently

  9. Superconductivity in palladium-doped 2H-TaS2

    Science.gov (United States)

    Zhou, M. H.; Li, X. C.; Dong, C.

    2018-06-01

    A series of Pd x TaS2 (0.01 ≤ x ≤ 0.08) samples were prepared and characterized via scanning electron microscope, x-ray powder diffraction, resistivity, magnetization and specific heat measurements. The lattice parameter c associated with the interlayer distance increases monotonically with the Pd content while the parameter a remains essentially constant. The crystal structure of Pd0.08TaS2 has been determined and refined by Rietveld refinement. Pd0.08TaS2 is hexagonal (space group: P31c) with lattice parameters a = 3.3151(1) Å, c = 12.1497(9) Å. The superconducting transition temperature T c (0.8 K) of TaS2 can be dramatically enhanced by Pd doping, and the maximum T c of 4.2 K, about five times the T c of pure TaS2, is obtained in Pd0.04TaS2. We have determined the superconducting parameters of Pd0.04TaS2, and found that the enhancement of T c can be attributed to the increase of density of states at the Fermi level. The charge density wave (CDW) of TaS2 is gradually suppressed with Pd doping and disappears in Pd0.06TaS2. This suggests that there is a competitive interplay between superconductivity and CDW in this system.

  10. Tumor rectal como presentación de sífilis primaria

    OpenAIRE

    CASELLI M,GINO; PINEDO M,GEORGE; NIKLITSCHEK L,SERGIO

    2009-01-01

    En la era de la infección por VIH, ha habido un resurgimiento de enfermedades en franca disminución en el mundo occidental como sífilis. Sin lugar a dudas siguen siendo un dilema diagnóstico algunas manifestaciones clínicas como sífilis rectal en pacientes portadores de VIH. Frente a un tumor rectal en un paciente VIH se debe tener en cuenta en el diagnóstico diferencial a esta patología. Presentamos un caso de un paciente portador de VIH que consultó por tenesmo rectal asociado a rectorragia...

  11. Physical properties and the Peierls instability of Li0.82[Pt(S2C2(CN)2)2] · 2H2O

    DEFF Research Database (Denmark)

    Ahmad, M. M.; Turner, D. J.; Underhill, A. E.

    1984-01-01

    The infrared reflectivity, the temperature-dependent conductivity, and thermopower of the one-dimensional conductor Li0.82[Pt(S2C2(CN)2)2] · 2H2O, LiPt(mnt), is presented. It undergoes a simple Peierls transition at Tc=215 K, which is not influenced by correlations or by cation ordering. The meta...

  12. Enhanced H2S Sensing Performance of a p-type Semiconducting PdO-NiO Nanoscale Heteromixture

    Science.gov (United States)

    Balamurugan, C.; Jeong, Y. J.; Lee, D. W.

    2017-10-01

    Semiconducting nanocrystalline nickel oxide (NiO) and PdO-doped NiO heteromixture (2, 5 and 10 wt%) have been synthesized via a metal-citrate complex method. The obtained materials were further characterized using TG/DTA, FT-IR, UV-vis, XRD, XPS, BET/BJH, SEM and TEM analyses to determine their structural and morphological properties. The results indicated that the spherical, uniform PdO nanoparticles were densely deposited on the NiO surface mainly in diameters of 10-15 nm. Moreover, the existence of various defect states was also analyzed with the help of photoluminescence (PL) spectroscopy. The gas response characteristics of synthesized materials were evaluated in the presence and absence of toxic gases such as hydrogen sulfide (H2S), carbon monoxide (CO), liquid petroleum gas (LPG), and ethanol (C2H5OH). The experimental results revealed that the sensitivity and selectivity of the NiO-based sensor material are dependent on the weight% of PdO loading in the NiO nanopowder. Among the investigated compound, the 5 wt% PdO-doped NiO sensor material showed excellent sensitivity and selectivity to 100 ppm H2S with a fast response/recovery characteristics of 6 s and 10 s, respectively. Furthermore, the 5 wt% PdO-doped NiO based sensor showed a linear relationship between the different concentrations of H2S gas and a significantly higher response to H2S even at the low concentration of 20 ppm (43%) at 60 °C. The dominant H2S gas sensing mechanisms in the NiO and 5 wt% PdO-doped NiO nanomaterials are systematically discussed based on the obtained characterization results.

  13. Synthesis and characterization of visible-active molybdenum disulfide (2H-MoS2) nanospheres

    International Nuclear Information System (INIS)

    Cheah, A. J.; Chiu, W. S.; Khiew, P. S.; Radiman, S.; Hamid, M. A. A.

    2015-01-01

    In current study, a novel 2H-MoS 2 nanospheres were successfully synthesized and underwent structural- as well as optical-property characterizations. The MoS 2 were prepared by one pot hydrothermal approach through adopting L-cysteine as environmentally-benignchalcogenide precursor. TEM image shows that the as-synthesized MoS 2 appear to be spherical in shape with size distribution in the range of 120 nm – 180 nm. HRTEM lattice-fringes imaging further elucidate that the interlayer spacing at the edges is equal to be 0.62 nm that correspond to (002) plane stacking. Also, the HRTEM image clearly-illustrate that the internal microstructure of MoS 2 composed of randomly-arrayed alternating layers, which render the postulation that the formation of nanosphere is driven by self-assembly of individual layers into globular morphology. XRD diffractogram that appear to be broad and unresolved reveal the partially crystalline nature of the sample. Optical-absorption spectra depicts the sample is visible active with featureless absorption, which can attribute to indirect transition of the excitions generated. By using Tauc plot, the bandgap energy is determined to be 1.75 eV, which reflect the nanospheres are indeed visible-active nanostructures

  14. GAS PHASE STRUCTURE AND STABILITY OF COMPLEX FORMED BY H2O, NH3, H2S AND THEIR METHYL DERIVATIVES WITH THE CATION CO2+

    Directory of Open Access Journals (Sweden)

    Cahyorini Kusumawardani

    2010-06-01

    Full Text Available Ab initio molecular orbital calculations at the Hartree-Fock-Self Consistent Field (HF-SCF have been performed in order to determine the structure and gas phase energies of complex formed by the Lewis bases of H2O, NH3, H2S and their methyl derivatives with the cation Co2+. The relative basicities of the base studied depend on both the substituent. The gas-phase interaction energies computed by the SCF method including electron correlation Møller-Plesset 2 (MP2 dan Configuration Iteration (CI were comparable in accuracy. The binding energies computed by these two methods reach the targeted chemical accuracy.   Keywords: ab initio calculation, cobalt complex, structure stability

  15. Electrochemical migration, whisker formation, and corrosion behavior of printed circuit board under wet H2S environment

    International Nuclear Information System (INIS)

    Zou, Shiwen; Li, Xiaogang; Dong, Chaofang; Ding, Kangkang; Xiao, Kui

    2013-01-01

    Highlights: •The electrochemical migration, whisker formation, and corrosion behavior of PCB under wet H 2 S environment were observed and studied systematically. •The process of electrochemical migration of solder joints is explained. •The corrosion mechanism of PCB interconnectors induced by micro pores under wet H 2 S environment is discussed, and the corrosion reaction model is proposed. -- Abstract: Electrochemical migration, whisker formation, and corrosion behavior of printed circuit board (PCB) under wet H 2 S environment were analyzed by environment scanning electron microscope (ESEM), Energy dispersive X-ray spectroscopy (EDS) with mapping and element phase cluster (EPC) techniques, Raman Spectrum analysis and electrochemical impedance spectroscopy (EIS) technology. The results showed that nonuniform corrosion behavior occurred on PCB surfaces under 1 ppm wet H 2 S at 40 °C; whiskers formed on the inner sidewall of via-holes with a growth rate of 1.2 Å/s; numerous corrosion products migrated through the pore of plated gold layer, which broke off the protective layer. The corrosion rate was accelerated according to the big-cathode-small-anode model

  16. Microkinetics of H2S Removal by Zinc Oxide in the Presence of Moist Gas Atmosphere

    Institute of Scientific and Technical Information of China (English)

    Huiling Fan; Chunhu Li; Hanxian Guo; Kechang Xie

    2003-01-01

    The microkinetics of H2S removal by ZnO desulfurization in H2O-CO2-N2, H2O-CO-N2 andH2O-O2-N2 gas mixtures was studied by thermogravimetric analysis. Experiments were carried out with100 120 mesh ZnO powder at temperatures from 473 K to 563 K. The results show that the kineticbehaviors of desulfurization could all be described by an improved shrinking-core model. The activationenergies of the reaction and the diffusion in different gas atmospheres were estimated.

  17. Chlorine dioxide as phenol and H2S scavenger - formation of halogenated phenols and subsequent environmental risk

    Energy Technology Data Exchange (ETDEWEB)

    Melbye, Alf G.; Faksness, Liv-Guri; Knudsen, Boerre Leif

    2006-03-15

    Formation of halogenated phenols as side products from treatment of produced water with aqueous chlorine dioxide has been investigated. The literature describes formation of halogenated hydrocarbons in effluent treatment using chlorine, hypochlorite and chlorine dioxide. A new chlorine dioxide product, originally intended as a H2S scavenger in the oil and gas industry, has been tested both as a phenol scavenger and H2S-scavenger for produced water applications. The concern about the possible formation of halogenated by-products initiated laboratory testing of chlorine dioxide as phenol and H2S scavenger for produced water applications. The tests also included synthetic matrixes containing phenols, and the tests show that halogenated phenols, mainly brominated species, are found in produced water after treatment with chlorine dioxide. Due to potential environmental risk from halogenated organic contaminants, the use of chlorine dioxide as phenol and H2S scavenger is not recommended. (Author)

  18. CO2, SO2, and H2S Degassing Related to the 2009 Redoubt Eruption, Alaska

    Science.gov (United States)

    Werner, C. A.; Kelly, P. J.; Evans, W.; Doukas, M. P.; McGimsey, R. G.; Neal, C. A.

    2012-12-01

    The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions with 35 airborne measurements of CO2, SO2, and H2S that span from October 2008 to August 2010. Increases in CO2 degassing were detected up to 5 months prior to the eruption and varied between 3630 and 9020 tonnes per day (t/d) in the 6 weeks prior to the eruption. Increased pre-eruptive CO2 degassing was accompanied by comparatively low S emission, resulting in molar C/S ratios that ranged between 30-60. However, the C/S ratio dropped to 2.4 coincident with the first phreatic explosion on March 15, 2009, and remained steady during the explosive (March 22 - April 4, 2009), effusive dome-building (April 5 - July 1, 2009), and waning phases (August 2009 onward) of the eruption. Observations of ice-melt rates, melt water discharge, and water chemistry in the months leading up to the eruption suggested that surface waters represented drainage from surficial, perched reservoirs of condensed magmatic steam and glacial meltwater. While the surface waters were capable of scrubbing many thousands of t/d of SO2, sampling of these fluids revealed that only a few hundred tonnes of SO2 was reacting to a dissolved component each day. This is also much less than the ~ 2100 t/d SO2 expected from degassing of magma in the upper crust (3-6.5 km), where petrologic analysis shows the final magma equilibration occurred. Thus, the high pre-eruptive C/S ratios observed could reflect bulk degassing of upper-crustal magma followed by nearly complete loss of SO2 in a magmatic-hydrothermal system. Alternatively, high C/S ratios could be attributed to degassing of low silica andesitic magma that intruded into the mid-crust in the 5 months prior to eruption; modeling suggests that mixing of this magma with pre-existing high silica andesite magma or mush would have caused a reduction of the C/S ratio to a value consistent with that measured during the eruption. Monitoring emissions regularly

  19. Internal Gene Cassette from a Genotype S H9N2 Avian Influenza Virus Attenuates the Pathogenicity of H5 Viruses in Chickens and Mice

    Directory of Open Access Journals (Sweden)

    Xiaoli Hao

    2017-10-01

    Full Text Available H9N2 avian influenza virus (AIV of genotype S frequently donate internal genes to facilitate the generation of novel reassortants such as H7N9, H10N8, H5N2 and H5N6 AIVs, posing an enormous threat to both human health and poultry industry. However, the pathogenicity and transmission of reassortant H5 viruses with internal gene cassette of genotype S H9N2-origin in chickens and mice remain unknown. In this study, four H5 reassortants carrying the HA and NA genes from different clades of H5 viruses and the remaining internal genes from an H9N2 virus of the predominant genotype S were generated by reverse genetics. We found that all four H5 reassortant viruses showed attenuated virulence in both chickens and mice, thus leading to increased the mean death times compared to the corresponding parental viruses. Consistently, the polymerase activity and replication ability in mammalian and avian cells, and the cytokine responses in the lungs of chickens and mice were also decreased when compared to their respective parental viruses. Moreover, these reassortants transmitted from birds to birds by direct contact but not by an airborne route. Our data indicate that the internal genes as a whole cassette from genotype S H9N2 viruses play important roles in reducing the pathogenicity of the H5 recombinants in chickens and mice, and might contribute to the circulation in avian or mammalian hosts.

  20. Effects of metals doping on the removal of Hg and H{sub 2}S over ceria

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Lixia, E-mail: linglixia@tyut.edu.cn [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Zhao, Zhongbei; Zhao, Senpeng [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Wang, Qiang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi (China); Wang, Baojun, E-mail: wangbaojun@tyut.edu.cn [Key Laboratory of Coal Science and Technology (Taiyuan University of Technology), Ministry of Education and Shanxi Province, Taiyuan 030024, Shanxi (China); Zhang, Riguang [Key Laboratory of Coal Science and Technology (Taiyuan University of Technology), Ministry of Education and Shanxi Province, Taiyuan 030024, Shanxi (China); Li, Debao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi (China)

    2017-05-01

    Highlights: • Mn and Fe doped CeO{sub 2}(111) surfaces favor Hg capture via strong interaction. • HgS adsorbs on Mn and Fe/CeO{sub 2}(111) surfaces with molecule mode. • Hg is easily oxidized by the active S on Mn and Fe/CeO{sub 2}(111) surfaces. • Mn and Fe doped ceria have the potential to simultaneous remove Hg and H{sub 2}S. - Abstract: The effects of Mn and Fe doping into the CeO{sub 2}(111) surface on the simultaneous removal of Hg and H{sub 2}S was investigated, a density functional theory calculation with the on-site Coulomb interaction taken into account was adopted. The adsorptions of Hg-containing species on perfect CeO{sub 2}(111), Mn/CeO{sub 2}(111) and Fe/CeO{sub 2}(111) surfaces were studied, the results showed that Mn and Fe dopants facilitated Hg adsorption, and more charge transferred from Hg atom to the metal doped surfaces; HgS preferred to adsorb on the perfect surface with the dissociated mode, while with the molecular mode on Mn/CeO{sub 2}(111) and Fe/CeO{sub 2}(111) surfaces. The reaction mechanism show that the dissociated S by H{sub 2}S can easily react with Hg leading to the formation of HgS on Mn/CeO{sub 2}(111) and Fe/CeO{sub 2}(111) surfaces, which is crucial to capture mercury.

  1. An effective 2-band eg model of sulfur hydride H3S for high-Tc superconductivity

    Science.gov (United States)

    Nishiguchi, Kazutaka; Teranishi, Shingo; Miyao, Satoaki; Matsushita, Goh; Kusakabe, Koichi

    To understand high transition temperature (Tc) superconductivity in sulfur hydride H3S, we propose an effective 2-band model having the eg symmetry as the minimal model for H3S. Two eg orbitals centered on a sulfur S atom are chosen for the smallest representation of relevant bands with the van-Hove singularity around the Fermi levels except for the Γ-centered small hole pockets by the sulfur 3 p orbitals. By using the maximally localized Wannier functions, we derive the minimal effective model preserving the body-centered cubic (bcc) crystal symmetry of the H3S phase having the highest Tc ( 203 K under pressures) among the other polymorphs of H3S.

  2. H S Mavi

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. H S Mavi. Articles written in Bulletin of Materials Science. Volume 30 Issue 3 June 2007 pp 295-299 Nanomaterials. Raman study on single-walled carbon nanotubes with different laser excitation energies · S S Islam Khurshed Ahmad Shah H S Mavi A K Shaukla S Rath Harsh.

  3. Synthèse de composés oxygénés à partir de CO et H2 Synthesis of Oxygenated Compounds from CO and H2

    Directory of Open Access Journals (Sweden)

    Chaumette P.

    2006-11-01

    Full Text Available Dans cet article sont passés en revue les principaux produits oxygénés qui peuvent être obtenus en utilisant exclusivement le gaz de synthèse, par voie directe ou par l'intermédiaire du méthanol, aisément synthétisé à partir de CO et H2. Une comparaison est effectuée, qui porte essentiellement sur les modes de synthèse, les différents catalyseurs employés et leurs performances. L'aspect mécanistique est abordé en présentant les divers mécanismes proposés pour ces réactions. Il apparaît, dès à présent, que ces voies d'accès vers les produits oxygénés permettraient de remplacer les procédés utilisant les oléfines par des procédés utilisant le méthanol et le gaz de synthèse. In this article are reviewed the principal oxygenated products that can be produced exclusively from synthesis gas either by a straight-run process or through the use of methanol that can be easily obtained from CO and H2. A comparison is made between the synthesis processes, the different catalysts and their performances. An approach of the mechanistic aspects is undertaken by considering the various mechanistic routes proposed for these reactions. It already now appears that such ways of obtaining these oxygenated products would allow to replace processes using olefins by processes using methanol and synthesis gas.

  4. Chemical trapping and characterization of small oxoacids of sulfur (SOS) generated in aqueous oxidations of H2S.

    Science.gov (United States)

    Kumar, Murugaeson R; Farmer, Patrick J

    2018-04-01

    Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated during the oxidation of hydrogen sulfide, H 2 S, in aqueous solution. Unlike their alkyl homologs, there is a little data on their generation and speciation during H 2 S oxidation. These SOS may exhibit both nucleophilic and electrophilic reactivity, which we attribute to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivatization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC MS. In this report, we compare SOS formation from H 2 S oxidation by a variety of biologically relevant oxidants. These SOS appear relatively long lived in aqueous solution, and thus may be involved in the observed physiological effects of H 2 S. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Point defects in the 1 T' and 2 H phases of single-layer MoS2: A comparative first-principles study

    Science.gov (United States)

    Pizzochero, Michele; Yazyev, Oleg V.

    2017-12-01

    The metastable 1 T' phase of layered transition metal dichalcogenides has recently attracted considerable interest due to electronic properties, possible topological phases, and catalytic activity. We report a comprehensive theoretical investigation of intrinsic point defects in the 1 T' crystalline phase of single-layer molybdenum disulfide (1 T'-MoS2 ) and provide comparison to the well-studied semiconducting 2 H phase. Based on density functional theory calculations, we explore a large number of configurations of vacancy, adatom, and antisite defects and analyze their atomic structure, thermodynamic stability, and electronic and magnetic properties. The emerging picture suggests that, under thermodynamic equilibrium, 1 T'-MoS2 is more prone to hosting lattice imperfections than the 2 H phase. More specifically, our findings reveal that the S atoms that are closer to the Mo atomic plane are the most reactive sites. Similarly to the 2 H phase, S vacancies and adatoms in 1 T'-MoS2 are very likely to occur while Mo adatoms and antisites induce local magnetic moments. Contrary to the 2 H phase, Mo vacancies in 1 T'-MoS2 are expected to be an abundant defect due to the structural relaxation that plays a major role in lowering the defect formation energy. Overall, our study predicts that the realization of high-quality flakes of 1 T'-MoS2 should be carried out under very careful laboratory conditions but at the same time the facile defects introduction can be exploited to tailor physical and chemical properties of this polymorph.

  6. Hydrothermal fabrication of few-layer MoS2 nanosheets within nanopores on TiO2 derived from MIL-125(Ti) for efficient photocatalytic H2 evolution

    Science.gov (United States)

    Ye, Fei; Li, Houfen; Yu, Hongtao; Chen, Shuo; Quan, Xie

    2017-12-01

    Protons tend to bond strongly with unsaturated-coordinate S element located at the edge of nano-MoS2 and are consequently reduced to H2. Therefore, increasing the active S atoms quantity will be a feasible approach to enhance hydrogen evolution. Herein we developed a porous TiO2 derived from metal organic frameworks (MOFs) as scaffold to restrict the growth and inhibit the aggregation of MoS2 nanosheets. As a result, the thickness of the prepared MoS2 nanosheets was less than 3 nm (1-4 layers), with more edges and active S atoms being exposed. This few-layer MoS2-porous TiO2 exhibits a H2 evolution rate of 897.5 μmol h-1 g-1, which is nearly twice as much as free-stand MoS2 nanosheets and twenty times more than physical mixture of MoS2 with porous TiO2. The high performance is attributed to that more active edge sites in few-layer MoS2-porous TiO2 are exposed than pure MoS2. This work provides a new method to construct MOFs derived porous structures for controlling MoS2 to expose active sites for HER.

  7. H-2-incompatible bone marrow chimeras produce donor-H-2-restricted Ly-2 suppressor T-cell factor(s)

    International Nuclear Information System (INIS)

    Noguchi, M.; Onoe, K.; Ogasawara, M.; Iwabuchi, K.; Geng, L.; Ogasawara, K.; Good, R.A.; Morikawa, K.

    1985-01-01

    To study adaptive-differentiation phenomena of T lymphocytes, suppressor T-cell factors (TsF) produced by Ly-2+ splenic T cells from fully allogeneic mouse bone marrow chimeras were analyzed. AKR mice irradiated and reconstituted with B10 marrow cells (B10----AKR chimeras) produced an Ly-2+ TsF after hyperimmunization with sheep erythrocytes. The TsF suppressed primary antibody responses (to sheep erythrocytes) generated with spleen cells of mice of H-2b haplotype but not those of H-2k haplotype. Thus, this suppressor factor was donor-H-2-restricted. The immunoglobulin heavy chain variable region gene (Igh-V)-restricting element was not involved in this form of suppression. Similar results were obtained when TsF from B6----BALB/c and BALB/c----B6 chimeras were analyzed. The TsF from B10----AKR chimeras suppressed responses of B10.A(3R) and B10.A(5R) mice but not those of B10.A(4R). This finding showed that identity between the factor-producing cells and target spleen cells is required on the left-hand side of the E beta locus of the H-2 region and that the putative I-Jb locus is not involved in this form of suppression. The present results support the postulate that post-thymic differentiation in the presence of continued or repeated stimulation with antigen and donor-derived antigen-presenting cells generates donor-H-2-restricted T-cell clones that may predominate within the repertoire of the specific antigen being presented

  8. Synthesis of MoS2 and MoO2 for their applications in H2 generation and lithium ion batteries: a review

    International Nuclear Information System (INIS)

    Zhao Yufei; Zhang Yuxia; Yang Zhiyu; Yan Yiming; Sun Kening

    2013-01-01

    Scientists increasingly witness the applications of MoS 2 and MoO 2 in the field of energy conversion and energy storage. On the one hand, MoS 2 and MoO 2 have been widely utilized as promising catalysts for electrocatalytic or photocatalytic hydrogen evolution in aqueous solution. On the other hand, MoS 2 and MoO 2 have also been verified as efficient electrode material for lithium ion batteries. In this review, the synthesis, structure and properties of MoS 2 and MoO 2 are briefly summarized according to their applications for H 2 generation and lithium ion batteries. Firstly, we overview the recent advancements in the morphology control of MoS 2 and MoO 2 and their applications as electrocatalysts for hydrogen evolution reactions. Secondly, we focus on the photo-induced water splitting for H 2 generation, in which MoS 2 acts as an important co-catalyst when combined with other semiconductor catalysts. The newly reported research results of the significant functions of MoS 2 nanocomposites in photo-induced water splitting are presented. Thirdly, we introduce the advantages of MoS 2 and MoO 2 for their enhanced cyclic performance and high capacity as electrode materials of lithium ion batteries. Recent key achievements in MoS 2 - and MoO 2 -based lithium ion batteries are highlighted. Finally, we discuss the future scope and the important challenges emerging from these fascinating materials. (review)

  9. Assessment of sulphur and H2S corrosion by use of simultaneous ER, galvanic and optical measurements

    DEFF Research Database (Denmark)

    Hemmingsen, Tor; Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo

    2003-01-01

    Sulphur and H2S corrosion on carbon steel is relevant in a range of industrial applications, including oil and gas production, district heating systems, and geothermal energy production. Bacterial activity may participate in the sulphur cycle and contribute to H2S production. As a part...

  10. O Cloze como instrumento de avaliação de leitura nas séries iniciais

    Directory of Open Access Journals (Sweden)

    Márcia Maria Peruzzi Elia da Mota

    Full Text Available A literatura na área tem apontado a importância das habilidades referentes à leitura e escrita, especialmente quando se estuda o processo de alfabetização e suas dificuldades. Buscando verificar a validade do Cloze como instrumento de avaliação de leitura, o presente estudo foi elaborado tendo como principal objetivo comparar os escores do Cloze com o Teste de Desempenho Escolar (TDE, que apresenta, além de estudos de validade e precisão, também uma proposta de normatização. A amostra do estudo constituiu-se de quarenta e duas crianças, das quais dezenove eram alunas da 1ª série e vinte e três da 2ª série (no sistema atual, 2º ano e 3º ano do Ensino Fundamental de escolas particulares situadas no Interior de Minas. Os resultados mostram evidências de validade de critério e convergência para o Cloze e indicam sua utilidade como um teste de avaliação de leitura.

  11. SELECCION Y CARACTERIZACION DE CONSORCIOS BACTERIANOS CON POTENCIALIDAD DE REMOVE RCO2 Y H2S EN UNA ATMOSFERA DE BIOGAS

    OpenAIRE

    QUIROZ ESPINOZA, MADELAINE SOLANGE

    2013-01-01

    La búsqueda de alternativas al uso del petróleo ha generado un fuerte interés en el desarrollo de energías no convencionales, como el biogás. En la actualidad se han implementado métodos físicos y químicos para remover los principales contaminantes del biogás. Sin embargo, también han surgido otros métodos de remoción de contaminantes que utilizan procesos microbiológicos, como el uso de consorcios bacterianos. Estos procedimientos se caracterizan por su robustez frente a fluctuaciones ambien...

  12. The control of H2S in biogas using iron ores as in situ desulfurizers during anaerobic digestion process.

    Science.gov (United States)

    Zhou, Qiying; Jiang, Xia; Li, Xi; Jiang, Wenju

    2016-09-01

    In this study, five kinds of iron ores, limonite, hematite, manganese ore, magnetite and lava rock, were used as the in situ desulfurizers in the anaerobic digestion reactors to investigate their effects on controlling H2S in biogas. The results show that the addition of the five iron ores could significantly control the content of H2S in biogas, with the best performance for limonite. As limonite dosages increase (10-60 g/L), the contents of H2S in biogas were evidently decreased in the digesters with different initial sulfate concentrations (0-1000 mg/L). After the anaerobic digestion, the removed sulfur was mostly deposited on the surface of limonite. A possible mechanism of H2S control in biogas by limonite was proposed preliminarily, including adsorption, FeS precipitation, and Fe (III) oxidation. The results demonstrated that limonite was a promising in situ desulfurizer for controlling H2S in biogas with low cost and high efficiency.

  13. Observation of candidates for heavy positively charged S=-2 H+ dibaryon with a weak decay channel H+→Λ+p+π0

    International Nuclear Information System (INIS)

    Aslanyan, P.Zh.; Emel'yanenko, V.N.; Rikhvitskij, V.S.

    2001-01-01

    Two events were detected on the photographs from the JINR 2m propane bubble chamber exposed to a 10 GeV/c proton beam, which can be interpreted as heavy S=-2 H + stable dibaryon with a weak decay H + →Λ+p+π 0

  14. DFT studies on the mechanism of the reaction of C2H5S with NO2

    Science.gov (United States)

    Tang, Yi-Zhen; Sun, Hao; Pan, Ya-Ru; Pan, Xiu-Mei; Wang, Rong-Shun

    The mechanisms for the reaction of C2H5S with NO2 are investigated at the QCISD(T)/6-311++G(d, p)//B3LYP/6-311++G(d, p) level on both single and triple potential energy surfaces. The geometries, vibrational frequencies and zero-point energy (ZPE) corrections of all stationary points involved in the title reaction are calculated at the B3LYP/6-311++G(d, p) level. The results show that the reaction is more predominant on the single potential energy surface, while it is negligible on the triple potential energy surface. Without barrier height in the whole process, the major channel is R ? C2H5SONO (IM1 and IM2) ? P1 (C2H5SO+NO). With much heat released in the formation of C2H5SNO2 (IM3) and the transition state involved in the subsequent step more stable than reactants, P4 (CH3CHS + t-HONO) is subdominant product energetically.

  15. Structural match of heterogeneously nucleated Mn(OH)_2(s) nanoparticles on quartz under various pH conditions

    International Nuclear Information System (INIS)

    Jung, Haesung; Lee, Byeongdu; Jun, Young-Shin

    2016-01-01

    The early nucleation stage of Mn (hydr)oxide on mineral surfaces is crucial to understand its occurrence and the cycling of nutrients in environmental systems. However, there are only limited studies on the heterogeneous nucleation of Mn(OH)_2(s) as the initial stage of Mn (hydr)oxide precipitation. Here, we investigated the effect of pH on the initial nucleation of Mn(OH)_2(s) on quartz. Under various pH conditions of 9.8, 9.9, and 10.1, we analyzed the structural matches between quartz and heterogeneously nucleated Mn(OH)_2(s). The structural matches were calculated by measuring lateral and vertical dimensions using grazing incidence small angle X-ray scattering (GISAXS) and atomic force microscopy (AFM), respectively. We found that a poorer structural match occurred at a higher pH than at a lower pH. The faster nucleation at a higher pH condition accounted for the observed poorer structural match. By fitting the structural match using classical nucleation theory, we also calculated the interfacial energy between Mn(OH)_2(s) and water (γ_n_f = 71 ± 7 mJ/m"2). The calculated m values and γ_n_f provided the variance of interfacial energy between quartz and Mn(OH)_2(s): γ_s_n = 262–272 mJ/m"2. As a result, this study provides new qualitative and quantitative information about heterogeneous nucleation on environmentally an abundant mineral surface, quartz, and it offers important underpinnings for understanding the fate and transport of trace ions in environmental systems.

  16. Study of Room Temperature H2S Gas Sensing Behavior of CuO-modified BSST Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    H. M. Baviskar

    2008-05-01

    Full Text Available Thick films of (Ba0.1Sr0.9(Sn0.5Ti0.5O3 referred as BSST, were prepared by screen-printing technique. The preparation, characterization and gas sensing properties of pure and CuO-BSST mixed oxide semiconductors have been investigated. The mixed oxides were obtained by dipping the pure BSST thick films into 0.01 M aqueous solution of CuCl2, for different intervals of time. Pure BSST was observed to be less sensitive to H2S gas. However, mixed oxides of CuO and BSST were observed to be highly sensitive to H2S gas. Upon exposure to H2S gas, the barrier height of CuO-BSST intergranular regions decreases markedly due to the chemical transformation of CuO into well conducting CuS leading to a drastic decrease in resistance. The crucial gas response was found to H2S gas at room temperature and no cross sensitivity was observed to other hazardous and polluting gases. The effects of microstructure and doping concentration on the gas response, selectivity, response and recovery of the sensor in the presence of H2S gas were studied and discussed.

  17. Renner-Teller modelling of recent experimental spectra of H{sub 2}S{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Duxbury, Geoffrey [Department of Physics, SUPA, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glagow G4 0NG, Scotland (United Kingdom)

    2015-01-22

    Recently there has been a renewal of interest in the spectroscopy and dynamics of the formation and fragmentation of the hydrogen sulphide ion, including. rotationally resolved spectra of higher vibrational states of the ∼A{sup 2}A{sub 1}−∼X{sup 2}B{sub 1} system than were obtained previously, and a comprehensive imaging study of the photo-fragmentation routes of highly excited H{sub 2}S{sup +}. In collaboration with Ch. Jungen and A. Alijah I have extended our previous l basis approach to the calculation of the effects of orbital angular momentum in H{sub 2}S{sup +} to include the stretch - bender extensions, with the options of using either the K- or l basis. This new code is being used to calculate the complicated orbital angular momentum and spin-orbit coupling effects responsible for the ro-vibronic pattern measured in some of the new experimental results.

  18. Ensayos argumentativos en inglés como lengua extranjera y su escritura como una práctica social situada: revisión de conceptos

    Directory of Open Access Journals (Sweden)

    Pedro Antonio Chala

    2013-01-01

    Full Text Available Este artículo presenta una discusión sobre las tendencias teóricas que ven la escritura de ensayos argumentativos en inglés lengua extranjera como práctica social situada. Los conceptos que se exploran en este documento constituyen la base de una propuesta de investigación que aborda la escritura argumentativa desde una perspectiva innovadora, social, situada, y basada en la enseñanza de géneros que se puede ver como una alternativa para fomentar la escritura de ensayos en inglés lengua extranjera como una práctica social situada que trascienda los límites del salón de clase. La discusión de los conceptos se visualiza primero desde la teoría de aprendizaje de una segunda lengua y los dominios de la lingüística aplicada que fundamentan la propuesta. Luego se presentan, se exploran y se explican los conceptos centrales; éstos incluyen, primero, la escritura como práctica social situada, segundo, la escritura de ensayos argumentativos como un proceso dinámico de creación, y tercero, el género como acción social situada. Finalmente, el artículo presenta una reflexión sobre cómo estos conceptos se pueden entender e interrelacionar para que la escritura de ensayos argumentativos sea abordada como una práctica de alfabetización que contribuya a la formación de estudiantes de inglés lengua extranjera como escritores reflexivos, críticos y sociales.

  19. Initiation and developmental stages of steel corrosion in wet H2S environments

    International Nuclear Information System (INIS)

    Bai, Pengpeng; Zhao, Hui; Zheng, Shuqi; Chen, Changfeng

    2015-01-01

    Highlights: • The initiation and development stages of steel corrosion in wet H 2 S environment were investigated. • Preferential dissolution at the grain boundaries of steel allowed corrosion products to form and accumulate. • The shapes and crystal types of corrosion products at various steel layers differed. • With increasing duration time, the S 2− peak with a binding energy of 161.2 eV gradually decreased. • A model of the formation process of corrosion product films was proposed. - Abstract: The initiation and various developmental stages of steel corrosion in H 2 S environments were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Results revealed that grain boundaries corrode at the initiation stage and that corrosion products initially form on both sides of the grain boundary and then accumulate. Corrosion products grew at the interface between the steel and corrosion product layer at the developmental stage. XPS analyses showed the composition and valence states of the corrosion products, and a model of the formation process of corrosion product films was proposed

  20. Retrofitting existing chemical scrubbers to biotrickling filters for H2S emission control.

    Science.gov (United States)

    Gabriel, David; Deshusses, Marc A

    2003-05-27

    Biological treatment is a promising alternative to conventional air-pollution control methods, but thus far biotreatment processes for odor control have always required much larger reactor volumes than chemical scrubbers. We converted an existing full-scale chemical scrubber to a biological trickling filter and showed that effective treatment of hydrogen sulfide (H2S) in the converted scrubber was possible even at gas contact times as low as 1.6 s. That is 8-20 times shorter than previous biotrickling filtration reports and comparable to usual contact times in chemical scrubbers. Significant removal of reduced sulfur compounds, ammonia, and volatile organic compounds present in traces in the air was also observed. Continuous operation for >8 months showed stable performance and robust behavior for H2S treatment, with pollutant-removal performance comparable to that achieved by using a chemical scrubber. Our study demonstrates that biotrickling filters can replace chemical scrubbers and be a safer, more economical technique for odor control.

  1. Energy recovery of the H2S and CO2 elimination with technology by hybrid plasma

    International Nuclear Information System (INIS)

    Salazar T, J. A.

    2014-01-01

    This document is a research focused on energy recovery from acid gas removal contained in natural gas as hydrogen sulfide (H 2 S) and carbon dioxide (CO 2 ), by obtaining highly energetic gas such as syngas (mixture of hydrogen and carbon monoxide, in particular) using plasma technology in its hybrid form, namely, gliding arc plasma, that has the property to behave like a thermal plasma and cold plasma, besides possessing among other virtues the ability to treat large flows continuously at atmospheric pressure without the need of using noble gases, with a power consumption of no more than 1000 W. Furthermore, this type of plasma has demonstrated to be a clean and efficient not only by high conversion rates of H 2 S (86%) and CO 2 (56%) and high percentages of selectivity in the production of hydrogen (H 2 ) and carbon monoxide carbon (CO) obtained in this work, but because it can even be seriously considered to replace other technologies currently used in the process of sweetening natural gas as adsorption, absorption and sequestering membranes. The results shown are based on a series of analysis, simulations, experiments and calculations, from the design of the plasma generating source based on an impulse-phase circuit, to the electrical characterization results and simulation by acquiring electrical signals, without forgetting the characterization of the resulting chemical components using various analytical techniques such as mass spectrometry, gas chromatography (GC), optical emission spectroscopy (OES), optical spectroscopy Fourier inverse transformed (XRD) and scanning electron microscopy (Sem), X-ray diffraction (XRD) and multi-gas detectors (iBrid MX6). Additionally, performed chemical kinetics and reaction mechanism of the compounds involved in the degradation of H 2 S and CO 2 similar to those experienced as well as the study of energy efficiency (Ece), specific energy (Se), all this to meet a projects needs 127499, entitled -Development of alternative

  2. Economic assessment of biogas-to-electricity generation system with H2S removal by activated carbon in small pig farm

    International Nuclear Information System (INIS)

    Pipatmanomai, Suneerat; Kaewluan, Sommas; Vitidsant, Tharapong

    2009-01-01

    This study was conducted to assess the economic feasibility of electricity generation from biogas in small pig farms with and without the H 2 S removal prior to biogas utilisation. The 2% potassium iodide (KI) impregnated activated carbon selected as H 2 S adsorbent was introduced to a biogas-to-electricity generation system in a small pig farm in Thailand as a case study. With the average inlet H 2 S concentration of about 2400 ppm to the adsorption unit, the H 2 S removal efficiency could reach 100% with the adsorption capacity of 0.062 kg of H 2 S/kg of adsorbent. Under the reference scenario (i.e., 45% subsidy on digester installation and fixed electricity price at 0.06 Euro/kWh) and based on an assumption that the biogas was fully utilised for electricity generation in the system, the payback period for the system without H 2 S removal was about 4 years. With H 2 S removal, the payback period was within the economic life of digester but almost twice that of the case without H 2 S removal. The impact of electricity price could be clearly seen for the case of treated biogas. At the electricity price fixed at 0.07 Euro/kWh, the payback period for the case of treated biogas was reduced to about 5.5 years, with a trend to decrease at higher electricity prices. For both treated and untreated biogas, the governmental subsidy was the important factor determining the economics of the biogas-to-electricity systems. Without subsidy, the payback period increased to almost 7 years and about 11 years for the case of untreated and treated biogas, respectively, at the reference electricity price. Although the H 2 S removal added high operation cost to the system, it is still highly recommended not only for preventing engine corrosion but also for the environment benefit in which air pollution by H 2 S/SO 2 emission and impact on human health could be potentially reduced. (author)

  3. Reaction of H{sub 2}S with MoRu(CO){sub 6}(dppm){sub 2} to give H{sub 2} and a bridged-sulfide product via hydrido-sulfhydryl intermediates (dppm equals Ph{sub 2}PCH{sub 2}PPh{sub 2})

    Energy Technology Data Exchange (ETDEWEB)

    Khorasani-Motlagh, M. [Sistan and Baluchestan Univ., Zahedan (Iran, Islamic Republic of). Dept. of Chemistry; Safari, N. [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Chemistry; Pamplin, C.B.; Patrick, B.O.; James, B.R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemistry

    2006-02-15

    The reactivity of hydrogen sulphide toward transition metal complexes was studied with particular focus on the reactions of hydrogen sulphide (H{sub 2}S) with solutions of bimetallic-dppm complexes. The complex MoRu(CO){sub 6}({mu}-dppm){sub 2} (1) (dppm equals Ph{sub 2}PCH{sub 2}PPh{sub 2}) reaction toward hydrogen sulphide was examined because of the fact that Ru is the second-row analogue of Fe and because of the key role of sulphur ligands in the Mo-Fe enzyme systems. This paper reported on the interaction of the Mo-Ru complex with hydrogen sulphide to form the bridged sulphide complex Mo(CO){sub 2}({mu}-CO)({mu}-S)(dppm){sub 2}Ru(CO) which can be synthesized with elemental sulphur. Oxidative addition of H{sub 2}S to MoRu(CO){sub 6}({mu}-dppm){sub 2} (1) at 20 degrees C in toluene yields an isolable complex formulated as Mo(CO){sub 3}({mu}-SH)({mu}-CO)({mu}-dppm){sub 2}RuH(CO) (2) via the possible intermediate Mo(CO){sub 3}({mu}-H)({mu}-CO)({mu}-dppm){sub 2}Ru(SH)(CO) (4) (dppm equals Ph{sub 2}PCH{sub 2}PPh{sub 2}) that is detectable at lower temperatures. Over 2 days, species 2 in toluene lost H{sub 2} (and CO) to yield the bridged-sulfide product, Mo(CO){sub 2}({mu}-CO)({mu}-S)({mu}-dppm){sub 2}Ru(CO) (5) that is also formed directly from the reaction of 1 with elemental sulfur. The solid-state molecular structure of 5 was determined by X-ray crystallography. A further hydrido-sulfhydryl species was found to be in equilibrium with 2 at ambient temperature. It was concluded that it is not impossible that hydrogen sulphide can react in a concerted manner with dimetallic precursors, without prior formation of an adduct. 24 refs., 2 tabs., 3 figs.

  4. Determination of the 1s2{\\ell }2{{\\ell }}^{\\prime } state production ratios {{}^{4}P}^{o}/{}^{2}P, {}^{2}D/{}^{2}P and {{}^{2}P}_{+}/{{}^{2}P}_{-} from fast (1{s}^{2},1s2s\\,{}^{3}S) mixed-state He-like ion beams in collisions with H2 targets

    Science.gov (United States)

    Benis, E. P.; Zouros, T. J. M.

    2016-12-01

    New results are presented on the ratio {R}m={σ }{T2p}( {}4P)/{σ }{T2p}({}2P) concerning the production cross sections of Li-like 1s2s2p quartet and doublet P states formed in energetic ion-atom collisions by single 2p electron transfer to the metastable 1s2s {}3S component of the He-like ion beam. Spin statistics predict a value of R m = 2 independent of the collision system in disagreement with most reported measurements of {R}m≃ 1{--}9. A new experimental approach is presented for the evaluation of R m having some practical advantages over earlier approaches. It also allows for the determination of the separate contributions of ground- and metastable-state beam components to the measured spectra. Applying our technique to zero-degree Auger projectile spectra from 4.5 MeV {{{B}}}3+ (Benis et al 2002 Phys. Rev. A 65 064701) and 25.3 MeV {{{F}}}7+ (Zamkov et al 2002 Phys. Rev. A 65 062706) mixed state (1{s}2 {}1S,1s2s {}3S) He-like ion collisions with H2 targets, we report new values of {R}m=3.5+/- 0.4 for boron and {R}m=1.8+/- 0.3 for fluorine. In addition, the ratios of {}2D/{}2P and {{}2P}+/{{}2P}- populations from either the metastable and/or ground state beam component, also relevant to this analysis, are evaluated and compared to previously reported results for carbon collisions on helium (Strohschein et al 2008 Phys. Rev. A 77 022706) including a critical comparison to theory.

  5. Energy recovery of the H{sub 2}S and CO{sub 2} elimination with technology by hybrid plasma; Recuperacion energetica de la eliminacion de H{sub 2}S y CO{sub 2} con tecnologia por plasma hibrido

    Energy Technology Data Exchange (ETDEWEB)

    Salazar T, J. A.

    2014-07-01

    This document is a research focused on energy recovery from acid gas removal contained in natural gas as hydrogen sulfide (H{sub 2}S) and carbon dioxide (CO{sub 2}), by obtaining highly energetic gas such as syngas (mixture of hydrogen and carbon monoxide, in particular) using plasma technology in its hybrid form, namely, gliding arc plasma, that has the property to behave like a thermal plasma and cold plasma, besides possessing among other virtues the ability to treat large flows continuously at atmospheric pressure without the need of using noble gases, with a power consumption of no more than 1000 W. Furthermore, this type of plasma has demonstrated to be a clean and efficient not only by high conversion rates of H{sub 2}S (86%) and CO{sub 2} (56%) and high percentages of selectivity in the production of hydrogen (H{sub 2}) and carbon monoxide carbon (CO) obtained in this work, but because it can even be seriously considered to replace other technologies currently used in the process of sweetening natural gas as adsorption, absorption and sequestering membranes. The results shown are based on a series of analysis, simulations, experiments and calculations, from the design of the plasma generating source based on an impulse-phase circuit, to the electrical characterization results and simulation by acquiring electrical signals, without forgetting the characterization of the resulting chemical components using various analytical techniques such as mass spectrometry, gas chromatography (GC), optical emission spectroscopy (OES), optical spectroscopy Fourier inverse transformed (XRD) and scanning electron microscopy (Sem), X-ray diffraction (XRD) and multi-gas detectors (iBrid MX6). Additionally, performed chemical kinetics and reaction mechanism of the compounds involved in the degradation of H{sub 2}S and CO{sub 2} similar to those experienced as well as the study of energy efficiency (Ece), specific energy (Se), all this to meet a projects needs 127499, entitled

  6. H2@Scale Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Pivovar, Bryan

    2017-03-31

    Final report from the H2@Scale Workshop held November 16-17, 2016, at the National Renewable Energy Laboratory in Golden, Colorado. The U.S. Department of Energy's National Renewable Energy Laboratory hosted a technology workshop to identify the current barriers and research needs of the H2@Scale concept. H2@Scale is a concept regarding the potential for wide-scale impact of hydrogen produced from diverse domestic resources to enhance U.S. energy security and enable growth of innovative technologies and domestic industries. Feedback received from a diverse set of stakeholders at the workshop will guide the development of an H2@Scale roadmap for research, development, and early stage demonstration activities that can enable hydrogen as an energy carrier at a national scale.

  7. H2S induced coma and cardiogenic shock in the rat: Effects of phenothiazinium chromophores

    Science.gov (United States)

    SONOBE, TAKASHI; HAOUZI, PHILIPPE

    2015-01-01

    Context Hydrogen sulfide (H2S) intoxication produces an acute depression in cardiac contractility-induced circulatory failure, which has been shown to be one of the major contributors to the lethality of H2S intoxication or to the neurological sequelae in surviving animals. Methylene blue (MB), a phenothiazinium dye, can antagonize the effects of the inhibition of mitochondrial electron transport chain, a major effect of H2S toxicity. Objectives We investigated whether MB could affect the immediate outcome of H2S-induced coma in unanesthetized animals. Second, we sought to characterize the acute cardiovascular effects of MB and two of its demethylated metabolites—azure B and thionine—in anesthetized rats during lethal infusion of H2S. Materials and methods First, MB (4 mg/kg, intravenous [IV]) was administered in non-sedated rats during the phase of agonal breathing, following NaHS (20 mg/kg, IP)-induced coma. Second, in 4 groups of urethane-anesthetized rats, NaHS was infused at a rate lethal within 10 min (0.8 mg/min, IV). Whenever cardiac output (CO) reached 40% of its baseline volume, MB, azure B, thionine, or saline were injected, while sulfide infusion was maintained until cardiac arrest occurred. Results Seventy-five percent of the comatose rats that received saline (n = 8) died within 7 min, while all the 7 rats that were given MB survived (p = 0.007). In the anesthetized rats, arterial, left ventricular pressures and CO decreased during NaHS infusion, leading to a pulseless electrical activity within 530 s. MB produced a significant increase in CO and dP/dtmax for about 2 min. A similar effect was produced when MB was also injected in the pre-mortem phase of sulfide exposure, significantly increasing survival time. Azure B produced an even larger increase in blood pressure than MB, while thionine had no effect. Conclusion MB can counteract NaHS-induced acute cardiogenic shock; this effect is also produced by azure B, but not by thionine, suggesting

  8. A Study on the Corrosion Behavior of Carbon Steel Exposed to a H2S-Containing NH4Cl Medium

    Science.gov (United States)

    Wang, Hai-bo; Li, Yun; Cheng, Guang-xu; Wu, Wei; Zhang, Yao-heng

    2018-04-01

    NH4Cl corrosion failure often occurs in the overhead systems of hydrotreaters, and this failure is always accompanied by the appearance of H2S. A combination of electrochemical and surface spectroscopic (SEM/EDS, AFM, XRD) techniques was used to investigate the effect of different factors, including the surface roughness, temperature, dissolved oxygen, pH and H2S concentration, on the corrosion behavior of carbon steel in an NH4Cl environment with the presence of H2S. The effect of H2S concentrations (at the ppm level) on the corrosion behavior of carbon steel was systematically revealed. The experimental results clearly indicated that the corrosion rate reached a minimum value at 10 ppm H2S. The steel surface was covered by a uniform corrosion product film in a 10 ppm H2S environment, and the corrosion product film was tight and protective. The ammonia from NH4Cl helped maintaining the protectiveness of the corrosion films in this environment. Dissolved oxygen mainly accelerated the cathodic reaction. The cathodic limiting current density increased with increasing temperature, and the anodic branch polarization curves were similar at different temperatures. The anodic current density decreased as the pH decreased, and the cathodic current density increased as the pH decreased. The absolute surface roughness (R a) of carbon steel increased from 132.856 nm at 72 h to 153.973 nm at 144 h, and the rougher surface resulted in a higher corrosion rate. The critical innovation in this research was that multiple influential factors were revealed in the NH4Cl environment with the presence of H2S.

  9. A Study on the Corrosion Behavior of Carbon Steel Exposed to a H2S-Containing NH4Cl Medium

    Science.gov (United States)

    Wang, Hai-bo; Li, Yun; Cheng, Guang-xu; Wu, Wei; Zhang, Yao-heng

    2018-05-01

    NH4Cl corrosion failure often occurs in the overhead systems of hydrotreaters, and this failure is always accompanied by the appearance of H2S. A combination of electrochemical and surface spectroscopic (SEM/EDS, AFM, XRD) techniques was used to investigate the effect of different factors, including the surface roughness, temperature, dissolved oxygen, pH and H2S concentration, on the corrosion behavior of carbon steel in an NH4Cl environment with the presence of H2S. The effect of H2S concentrations (at the ppm level) on the corrosion behavior of carbon steel was systematically revealed. The experimental results clearly indicated that the corrosion rate reached a minimum value at 10 ppm H2S. The steel surface was covered by a uniform corrosion product film in a 10 ppm H2S environment, and the corrosion product film was tight and protective. The ammonia from NH4Cl helped maintaining the protectiveness of the corrosion films in this environment. Dissolved oxygen mainly accelerated the cathodic reaction. The cathodic limiting current density increased with increasing temperature, and the anodic branch polarization curves were similar at different temperatures. The anodic current density decreased as the pH decreased, and the cathodic current density increased as the pH decreased. The absolute surface roughness ( R a) of carbon steel increased from 132.856 nm at 72 h to 153.973 nm at 144 h, and the rougher surface resulted in a higher corrosion rate. The critical innovation in this research was that multiple influential factors were revealed in the NH4Cl environment with the presence of H2S.

  10. Hybrid MoS2/h-BN Nanofillers As Synergic Heat Dissipation and Reinforcement Additives in Epoxy Nanocomposites.

    Science.gov (United States)

    Ribeiro, Hélio; Trigueiro, João Paulo C; Silva, Wellington M; Woellner, Cristiano F; Owuor, Peter S; Cristian Chipara, Alin; Lopes, Magnovaldo C; Tiwary, Chandra S; Pedrotti, Jairo J; Villegas Salvatierra, Rodrigo; Tour, James M; Chopra, Nitin; Odeh, Ihab N; Silva, Glaura G; Ajayan, Pulickel M

    2017-09-26

    Two-dimensional (2D) nanomaterials as molybdenum disulfide (MoS 2 ), hexagonal boron nitride (h-BN), and their hybrid (MoS 2 /h-BN) were employed as fillers to improve the physical properties of epoxy composites. Nanocomposites were produced in different concentrations and studied in their microstructure, mechanical and thermal properties. The hybrid 2D mixture imparted efficient reinforcement to the epoxy leading to increases of up to 95% in tensile strength, 60% in ultimate strain, and 58% in Young's modulus. Moreover, an enhancement of 203% in thermal conductivity was achieved for the hybrid composite as compared to the pure polymer. The incorporation of MoS 2 /h-BN mixture nanofillers in epoxy resulted in nanocomposites with multifunctional characteristics for applications that require high mechanical and thermal performance.

  11. Highly luminescent S,N co-doped carbon quantum dots-sensitized chemiluminescence on luminol-H2 O2 system for the determination of ranitidine.

    Science.gov (United States)

    Chen, Jianqiu; Shu, Juan; Chen, Jiao; Cao, Zhiran; Xiao, An; Yan, Zhengyu

    2017-05-01

    S,N co-doped carbon quantum dots (N,S-CQDs) with super high quantum yield (79%) were prepared by the hydrothermal method and characterized by transmission electron microscopy, photoluminescence, UV-Vis spectroscopy and Fourier transformed infrared spectroscopy. N,S-CQDs can enhance the chemiluminescence intensity of a luminol-H 2 O 2 system. The possible mechanism of the luminol-H 2 O 2 -(N,S-CQDs) was illustrated by using chemiluminescence, photoluminescence and ultraviolet analysis. Ranitidine can quench the chemiluminescence intensity of a luminol-H 2 O 2 -N,S-CQDs system. So, a novel flow-injection chemiluminescence method was designed to determine ranitidine within a linear range of 0.5-50 μg ml -1 and a detection limit of 0.12 μg ml -1 . The method shows promising application prospects. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Extreme population inversion in the fragments formed by UV photoinduced S-H bond fission in 2-thiophenethiol.

    Science.gov (United States)

    Ingle, Rebecca A; Karsili, Tolga N V; Dennis, Gregg J; Staniforth, Michael; Stavros, Vasilios G; Ashfold, Michael N R

    2016-04-28

    H atom loss following near ultraviolet photoexcitation of gas phase 2-thiophenethiol molecules has been studied experimentally, by photofragment translational spectroscopy (PTS) methods, and computationally, by ab initio electronic structure calculations. The long wavelength (277.5 ≥ λ(phot) ≥ 240 nm) PTS data are consistent with S-H bond fission after population of the first (1)πσ* state. The partner thiophenethiyl (R) radicals are formed predominantly in their first excited Ã(2)A' state, but assignment of a weak signal attributable to H + R(X˜(2)A'') products allows determination of the S-H bond strength, D0 = 27,800 ± 100 cm(-1) and the Ã-X˜ state splitting in the thiophenethiyl radical (ΔE = 3580 ± 100 cm(-1)). The deduced population inversion between the à and X˜ states of the radical reflects the non-planar ground state geometry (wherein the S-H bond is directed near orthogonal to the ring plane) which, post-photoexcitation, is unable to planarise sufficiently prior to bond fission. This dictates that the dissociating molecules follow the adiabatic fragmentation pathway to electronically excited radical products. π* ← π absorption dominates at shorter excitation wavelengths. Coupling to the same (1)πσ* potential energy surface (PES) remains the dominant dissociation route, but a minor yield of H atoms attributable to a rival fragmentation pathway is identified. These products are deduced to arise via unimolecular decay following internal conversion to the ground (S0) state PES via a conical intersection accessed by intra-ring C-S bond extension. The measured translational energy disposal shows a more striking change once λ(phot) ≤ 220 nm. Once again, however, the dominant decay pathway is deduced to be S-H bond fission following coupling to the (1)πσ* PES but, in this case, many of the evolving molecules are deduced to have sufficiently near-planar geometries to allow passage through the conical intersection at extended S-H bond

  13. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR; F

    International Nuclear Information System (INIS)

    K.C. Kwon

    2002-01-01

    Removal of hydrogen sulfide (H(sub 2)S) from coal gasifier gas and sulfur recovery are key steps in the development of Department of Energy's (DOE's) advanced Vision 21 plants that employ coal and natural gas and produce electric power and clean transportation fuels. These Vision 21 plants will require highly clean coal gas with H(sub 2)S below 1 ppm and negligible amounts of trace contaminants such as hydrogen chloride, ammonia, alkali, heavy metals, and particulate. The conventional method of sulfur removal and recovery employing amine, Claus, and tail-gas treatment is very expensive. A second generation approach developed under DOE's sponsorship employs hot-gas desulfurization (HGD) using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process (DSRP). However, this process sequence does not remove trace contaminants and is targeted primarily towards the development of advanced integrated gasification combined cycle (IGCC) plants that produce electricity (not both electricity and transportation fuels). There is an immediate as well as long-term need for the development of cleanup processes that produce highly clean coal gas for next generation Vision 21 plants. To this end, a novel process is now under development at Research Triangle Institute (RTI) in which the H(sub 2)S in coal gas is directly oxidized to elemental sulfur over a selective catalyst. Such a process is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H(sub 2)S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objective of this research is to support the near- and long-term DOE efforts to commercialize this direct oxidation technology. Specifically, we aim to: Measure the kinetics of direct oxidation of H(sub 2)S to elemental sulfur over selective catalysts in the presence of major

  14. Anti-H-Y responses of H-2b mutant mice.

    Science.gov (United States)

    Simpson, E; Gordon, R D; Chandler, P R; Bailey, D

    1978-10-01

    Two strains of H-2b mutant mice, H-2ba and H-2bf, in which the mutational event took place at H-2K, make anti-H-Y cytotoxic T cell responses which are H-2-restricted, Db-associated and indistinguishable in target cell specificity from those of H-2b mice. Thus, alteration of the H-2K molecule affects neither the Ir gene controlling the response, nor the associative antigen. On the other hand, one H-2Db mutant strain, H-2bo, although it makes a good anti-H-Y cytotoxic response, shows target cell specificity restricted to its own Dbo antigen(s), and neither H-2b, H-2ba or H-2bf anti-H-Y cytotoxic cells kill H-2bo male target cells. Thus, the alteration of the H-2Db molecule does not affect the Ir gene of H-2b mice, but it does alter the H-2Db-associative antigen.

  15. Simultaneous removal of CO2 and H2S using MEA solution in a packed column absorber for biogas upgrading

    Directory of Open Access Journals (Sweden)

    Preecha Kasikamphaiboon

    2013-12-01

    Full Text Available Biogas production and utilization is an emerging alternative energy technology that has gained importance since the price of oil and gas has increased steadily over the last two decades. Biogas primarily consists of methane (CH4 and carbon dioxide (CO2 with smaller amounts of hydrogen sulfide (H2S and ammonia (NH3. For many applications the quality of biogas has to be improved. The main parameters that may require removal in upgrading systems are CO2 and H2S. This work presents the study of simultaneous absorption of CO2 and H2S by Monoethanolamine (MEA solution in a packed column. Simulated biogas containing 40% CO2 and 60% N2 and biogas generated from an anaerobic digestion plant were used as feed gas streams. The effects of gas flow rate, L/G ratio and absorbent concentration were investigated. The performance of the system was found to vary with process parameters. Increasing L/G ratio and MEA concentration causes the system efficiency to increase whereas increasing gas flow rate results in lower efficiency. An operating condition of L/G ratio of 83.3 ml/L, gas flow rate of 3 L/min and MEA concentration of 3 mol/L was found to remove more than 99.5% of CO2 and H2S from biogas. The volumetric overall mass-transfer coefficient (KGav for CO2 removal initially increases with increasing gas flow rate up to a certain value beyond which the coefficient becomes essentially constant. The KGav also increases with increasing L/G ratio throughout the range tested in this study.

  16. E2F-dependent accumulation of hEmi1 regulates S phase entry by inhibiting APC(Cdh1)

    DEFF Research Database (Denmark)

    Hsu, Jerry Y; Reimann, Julie D R; Sørensen, Claus S

    2002-01-01

    . At the G1-S transition, hEmi1 is transcriptionally induced by the E2F transcription factor, much like cyclin A. hEmi1 overexpression accelerates S phase entry and can override a G1 block caused by overexpression of Cdh1 or the E2F-inhibitor p105 retinoblastoma protein (pRb). Depleting cells of hEmi1...

  17. Anticorrosion performance of chromized coating prepared by pack cementation in simulated solution with H2S and CO2

    Science.gov (United States)

    Wang, Qin-Ying; Behnamian, Yashar; Luo, Hong; Wang, Xian-Zong; Leitch, Michael; Zeng, Hongbo; Luo, Jing-Li

    2017-10-01

    A hash service environment containing H2S and CO2 in oil industry usually causes corrosion of carbon steel. In this study, the chromized coatings with different deposited time were prepared on the surface of carbon steel by the method of pack cementation to enhance its corrosion resistance. Then the microstructure, hardness, corrosion resistance as well as the semiconductor behavior of coatings in the simulated solution with saturated H2S and CO2 were investigated. The results show that the content of Cr in coating was increased by prolonging deposited time, and both chromium carbides and chromium nitrides were formed. Furthermore, coatings display higher polarization resistance, Rp, than that of the substrate, indicating a higher resistance to charge transfer on coating surface. The corrosion rates of coatings with different deposited time were significantly lower than that of substrate. Chemical analysis showed the formation of heavy sulfides on the surface of substrates after corrosion, while the least corrosion products were detected on the surface of coating with deposited time of 12 h. Mott-Schottky results indicated that coating of 12 h displayed less defects than the other two coatings with deposited time of 4 h and 8 h, which will be beneficial to improve corrosion resistance. The investigation showed that chromized coatings exhibited high corrosion resistance and owned a potential application in oil industry for corrosion prevention.

  18. Tecidos moles (não resistentes: como se fossilizam?

    Directory of Open Access Journals (Sweden)

    Silvia Regina Gobbo

    2015-06-01

    Full Text Available A preservação de tecidos moles (não resistentes desperta atenção pela qualidade dos fósseis preservados, e pela raridade. Este trabalho faz ampla revisão do assunto, desfaz alguns dos mitos correntes sobre fossilização destes materiais, como anaerobiose e soterramento rápido, bem como assinala a relevância do papel da replicagem de estruturas morfológicas por colônias microbianas. No âmbito dos fatores que influenciam a preservação de tecidos não resistentes estão pH, processos de decomposição, soterramento rápido e mineralização rápida por meio de carbonatos ou fosfatos. É possível citar exemplos de fácies sedimentares nas quais há preservação de tecidos não resistentes, como os folhelhos pirobetuminosos, calcários litográficos, folhelhos e diatomitos. Destaca-se o papel das colônias microbianas, tanto na forma de microesferas, como aquelas não-esferulíticas. Os três mitos principais que se procurou desfazer no artigo são: (1 a presença de oxigênio; (2 o soterramento rápido e (3 as colônias microbianas.

  19. Availability of S from superphosphate and CaSO4.2H2O to alfafa (Medicago sativa L. Pers.) using tracer technique

    International Nuclear Information System (INIS)

    Aulakh, M.S.; Dev, G.

    1977-01-01

    The availability of S from superphosphate to alfalfa was evaluated and compared with CaSO 4 .2H 2 O (as the standard) in the greenhouse on a S deficient arid brown soil at 4 levels of applied S (0, 5, 10 and 20 ppm). A basal dose of N, P, K and Ca was made and the effect was studied for two growth stages (80 and 120 days). Sulphur application significantly increased the yield of dry matter, S content and total S removal in both the cuttings individually and for total harvest. In this effect, superphosphate was found to be more efficient. The radio-assay data confirmed that with graded levels of applied S, the fraction of fertilizer S in the plant increased without much off-setting S fraction from the native soil source, the effect being more with superphosphate treatment compared to CaSO 4 .2H 2 O. Phosphorus concentration in alfalfa decreased significantly with increasing level of applied S. The first cutting of alfalfa recorded higher P content in superphosphate series and in the second cutting, this difference between the two sources decreased. At optimum level of 20 ppm S, superphosphate was more effective than CaSO 4 .2H 2 O in narrowing N:S ratio to 11:1 and increasing S:P ratio to more than 1:1. (author)

  20. Improved interface properties of atomic-layer-deposited HfO{sub 2} film on InP using interface sulfur passivation with H{sub 2}S pre-deposition annealing

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hyun Soo [Department of Materials Science & Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Cho, Young Jin [Inorganic Material Lab., Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Department of Materials Science & Engineering and Inter-university Semiconductor Research Center, Seoul National University, Seoul 151-742 (Korea, Republic of); Seok, Tae Jun; Kim, Dae Hyun; Kim, Dae Woong [Department of Materials Science & Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Sang-Moon [Process Development Team, Semiconductor R& D Center, Samsung Electronics Co. Ltd, Hwasung 445-701 (Korea, Republic of); Park, Jong-Bong; Yun, Dong-Jin [Analytical Engineering Group, Platform Technology Lab., Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Kim, Seong Keun [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Hwang, Cheol Seong, E-mail: cheolsh@snu.ac.kr [Department of Materials Science & Engineering and Inter-university Semiconductor Research Center, Seoul National University, Seoul 151-742 (Korea, Republic of); Park, Tae Joo, E-mail: tjp@hanyang.ac.kr [Department of Materials Science & Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of)

    2015-12-01

    Highlights: • ALD HfO{sub 2} films were grown on InP for III–V compound-semiconductor-based devices. • S passivation was performed with (NH{sub 4}){sub 2}S solution and annealing under a H{sub 2}S atmosphere. • The H{sub 2}S annealing provided similar S profiles at the interface without surface damage. • The H{sub 2}S annealing was more effective to suppress interface state density due to thermal energy. - Abstract: Surface sulfur (S) passivation on InP substrate was performed using a dry process – rapid thermal annealing under H{sub 2}S atmosphere for III–V compound-semiconductor-based devices. The electrical properties of metal-oxide-semiconductor capacitor fabricated with atomic-layer-deposited HfO{sub 2} film as a gate insulator were examined, and were compared with the similar devices with S passivation using a wet process – (NH{sub 4}){sub 2}S solution treatment. The H{sub 2}S annealing provided solid S passivation with the strong resistance against oxidation compared with the (NH{sub 4}){sub 2}S solution treatment, although S profiles at the interface of HfO{sub 2}/InP were similar. The decrease in electrical thickness of the gate insulator by S passivation was similar for both methods. However, the H{sub 2}S annealing was more effective to suppress interface state density near the valence band edge, because thermal energy during the annealing resulted in stronger S bonding and InP surface reconstruction. Moreover, the flatband voltage shift by constant voltage stress was lower for the device with H{sub 2}S annealing.

  1. Acid Gas to Syngas (AG2S™) technology applied to solid fuel gasification: Cutting H_2S and CO_2 emissions by improving syngas production

    International Nuclear Information System (INIS)

    Bassani, Andrea; Pirola, Carlo; Maggio, Enrico; Pettinau, Alberto; Frau, Caterina; Bozzano, Giulia; Pierucci, Sauro; Ranzi, Eliseo; Manenti, Flavio

    2016-01-01

    Highlights: • Coal gasification with improved yield and reduced emissions. • AG2S™ process converts H_2S and CO_2 into syngas, elemental sulfur and water. • Techno-economic simulation of AG2S™ process is carried out. • Industrial case-study on the Sotacarbo S.p.A. gasification pilot plant is proposed. - Abstract: The paper deals with the application of the novel Acid Gas To Syngas (AG2S™) technology to the gasification of solid fuels. The AG2S technology is a completely new effective route of processing acid gases: H_2S and CO_2 are converted into syngas (CO and H_2) by means of a regenerative thermal reactor. To show the application of the AG2S technology, modeling and simulation advances for gasification systems are initially discussed. The multi-scale, multi-phase, and multi-component coal gasification system is described by means of detailed kinetic mechanisms for coal pyrolysis, char heterogeneous reactions and for successive gas-phase reactions. These kinetic mechanisms are then coupled with transport resistances resulting in first-principles dynamic modeling of non-ideal reactors of different types (e.g., downdraft, updraft, traveling grate), also including the catalytic effect of ashes. The generalized approach pursued in developing the model allows characterizing the main phenomena involved in the coal gasification process, including the formation of secondary species (e.g., COS, CS_2). This tool is here further validated on literature data and, then, adopted to demonstrate the AG2S effectiveness, where H_2S and CO_2 emissions are reduced with an increase of syngas production. The resulting process solution is more economically appealing with respect to the traditional Claus process and finds several application areas.

  2. Low-temperature solid-state preparation of ternary CdS/g-C_3N_4/CuS nanocomposites for enhanced visible-light photocatalytic H_2-production activity

    International Nuclear Information System (INIS)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

    2017-01-01

    Highlights: • CdS/g-C_3N_4/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C_3N_4/CuS show enhanced visible-light photocatalytic H_2 evolution activity. • The enhanced photocatalytic H_2 production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C_3N_4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C_3N_4/CuS composite exhibits a high visible-light photocatalytic H_2-production rate of 57.56 μmol h"−"1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na_2S/Na_2SO_3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C_3N_4/CuS composites show the enhanced visible-light photocatalytic H_2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C_3N_4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H_2-production activity.

  3. Synthesis and characterization of polymer eight-coordinate (enH 2)[Y III(pdta)(H 2O)] 2·10H 2O as well as the interaction of [Y III(pdta)(H 2O)] 22- with BSA

    Science.gov (United States)

    Liu, Bin; Wang, Jun; Wang, Xin; Liu, Bing-Mi; He, Ling-Ling; Xu, Shu-Kun

    2010-12-01

    The eight-coordinate (enH 2)[Y III(pdta)(H 2O)] 2·10H 2O (en = ethylenediamine and H 4pdta = 1,3-propylenediamine- N, N, N', N'-tetraacetic acid) was synthesized, meanwhile its molecular and crystal structures were determined by single-crystal X-ray diffraction technology. The interaction between [Y III(pdta)(H 2O)] 22- and bovine serum albumin (BSA) was investigated by UV-vis and fluorescence spectra. The results indicate that [Y III(pdta)(H 2O)] 22- quenched effectively the intrinsic fluorescence of BSA via a static quenching process with the binding constant ( Ka) of the order of 10 4. Meanwhile, the binding and damaging sites to BSA molecules were also estimated by synchronous fluorescence. Results indicate that the hydrophobic environments around Trp and Tyr residues were all slightly changed. The thermodynamic parameters (Δ G = -25.20 kJ mol -1, Δ H = -26.57 kJ mol -1 and Δ S = -4.58 J mol -1 K -1) showed that the reaction was spontaneous and exothermic. What is more, both Δ H and Δ S were negative values indicated that hydrogen bond and Van der Waals forces were the predominant intermolecular forces between [Y III(pdta)(H 2O)] 22- and BSA.

  4. In situ depot comprising phase-change materials that can sustainably release a gasotransmitter H2S to treat diabetic wounds.

    Science.gov (United States)

    Lin, Wei-Chih; Huang, Chieh-Cheng; Lin, Shu-Jyuan; Li, Meng-Ju; Chang, Yen; Lin, Yu-Jung; Wan, Wei-Lin; Shih, Po-Chien; Sung, Hsing-Wen

    2017-11-01

    Patients with diabetes mellitus are prone to develop refractory wounds. They exhibit reduced synthesis and levels of circulating hydrogen sulfide (H 2 S), which is an ephemeral gaseous molecule. Physiologically, H 2 S is an endogenous gasotransmitter with multiple biological functions. An emulsion method is utilized to prepare a microparticle system that comprises phase-change materials with a nearly constant temperature of phase transitions to encapsulate sodium hydrosulfide (NaHS), a highly water-labile H 2 S donor. An emulsion technique that can minimize the loss of water-labile active compounds during emulsification must be developed. The as-prepared microparticles (NaHS@MPs) provide an in situ depot for the sustained release of exogenous H 2 S under physiological conditions. The sustained release of H 2 S promotes several cell behaviors, including epidermal/endothelial cell proliferation and migration, as well as angiogenesis, by extending the activation of cellular ERK1/2 and p38, accelerating the healing of full-thickness wounds in diabetic mice. These experimental results reveal the strong potential of NaHS@MPs for the sustained release of H 2 S for the treatment of diabetic wounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Synthesis of ZnO comb-like nanostructures for high sensitivity H2S ...

    Indian Academy of Sciences (India)

    2017-09-15

    Sep 15, 2017 ... H2S gas sensor; ZnO comb-like nanostructures; chemical vapour deposition; vapour–solid growth; ... tube at a flow rate of 15 sccm, when the central temperature .... behaviour, in this case, under low input power implies ohmic.

  6. Syntheses of [5-2H]-uracil, [5-2H]-cytosine, [6-2H]-uracil and [6-2H]-cytosine

    International Nuclear Information System (INIS)

    Kiritani, Reiko; Asano, Takeyoshi; Fujita, Shin-ichi; Dohmaru, Takaaki; Kawanishi, Tetsuro

    1986-01-01

    Syntheses of [5- 2 H]-, [6- 2 H]-uracil and [5- 2 H]-, [6- 2 H]-cytosine were investigated. The catalytic reaction of uracil or cytosine with 2 H 2 gas in alkaline media gave rise to [6- 2 H]-compounds almost exclusively. On the other hand, the reaction of 5-bromouracil or 5-bromocytosine with 2 H 2 gas gave rise to a mixture of [5- 2 H]-, [6- 2 H]- and [5- 2 H, 6- 2 H]-compounds depending on the experimental conditions. By controlling the temperature, the pressure of 2 H 2 gas and the amount of catalyst, [5- 2 H]-uracil and [5- 2 H]-cytosine were obtained. The isotopic distribution in each product was measured by 1 H NMR spectroscopy combined with an HPLC method. (author)

  7. Quantum-tunneling isotope-exchange reaction H2+D-→HD +H-

    Science.gov (United States)

    Yuen, Chi Hong; Ayouz, Mehdi; Endres, Eric S.; Lakhamanskaya, Olga; Wester, Roland; Kokoouline, Viatcheslav

    2018-02-01

    The tunneling reaction H2+D-→HD +H- was studied in a recent experimental work at low temperatures (10, 19, and 23 K) by Endres et al. [Phys. Rev. A 95, 022706 (2017), 10.1103/PhysRevA.95.022706]. An upper limit of the rate coefficient was found to be about 10-18cm3 /s. In the present study, reaction probabilities are determined using the ABC program developed by Skouteris et al. [Comput. Phys. Commun. 133, 128 (2000), 10.1016/S0010-4655(00)00167-3]. The probabilities for ortho-H2 and para-H2 in their ground rovibrational states are obtained numerically at collision energies above 50 meV with the total angular momentum J =0 -15 and extrapolated below 50 meV using a WKB approach. Thermally averaged rate coefficients for ortho- and para-H2 are obtained; the largest one, for ortho-H2, is about 3.1 ×10-20cm3 /s, which agrees with the experimental results.

  8. Reduction of H{sub 2}S from biogas by using environmental air

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, S.N.

    1997-04-01

    First a general description is given about environmental aspects of producing biogas from manures, the anaerobic digestion process, and inhibition by ammonia. Two experiment were carried out to determine the effect of air on reducing H{sub 2}S from biogas. In both the experiments the same amount of degassed manure (1.5 lit) collected from Boddam Biogas Plant is initially used. Everyday feed the digester (3 lit of total volume) was fed by 500 ml of pig liquid manure, when the rate or Volatile Fatty Acid production in the experimental tanks goes down. First experiment was for trial and the biogas produced were measured only qualitatively. In this experiment 5% of air was used in the experimental tank. It was found that the biogas production was increased, though negligibly, in the experimental tank. In this experiment the amount of gas production was more in experimental tank, as well as, less H{sub 2}S concentration. The following biochemical parameters was measured of the manure used for biogas production. TS (Total Solid), VFA (Volatile Fatty Acid), Analysis of biogas. (LN) 30 refs.

  9. Synthesis of ZnO nanorods by spray pyrolysis for H{sub 2}S gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, S.D.; Patil, G.E. [Materials Research Lab., K.T.H.M. College, Nashik 422 005 (India); Kajale, D.D. [Materials Research Lab., Arts, Commerce and Science College, Nandgaon 423 106 (India); Gaikwad, V.B. [Materials Research Lab., K.T.H.M. College, Nashik 422 005 (India); Jain, G.H., E-mail: gotanjain@rediffmail.com [Materials Research Lab., K.T.H.M. College, Nashik 422 005 (India)

    2012-07-05

    Highlights: Black-Right-Pointing-Pointer Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique. Black-Right-Pointing-Pointer ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H{sub 2}S gas (100 ppm) at 50 Degree-Sign C. Black-Right-Pointing-Pointer This ZnO thin film has potential in application of room temperature H{sub 2}S gas sensing. - Abstract: Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique (SPT). The equal amount of methanol and water is used as a solvent to dissolve the AR grade Zinc acetate for precursor solution. This solution is sprayed on to the glass substrate heated at 350 Degree-Sign C. The films were characterized by ultra-violet spectroscopy (UV), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The deposition of thin films results in a layer comprising well-shaped hexagonal ZnO nanorods with diameter of 90-120 nm and length of up to 200 nm. The gas sensing properties of these films have been investigated for various interfering gases such as CO{sub 2}, CO, ethanol, NH{sub 3} and H{sub 2}S, etc. at operating temperature from 30 Degree-Sign (room temperature) to 450 Degree-Sign C. The results indicate that the ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H{sub 2}S gas (100 ppm) at 50 Degree-Sign C. The hexagonal pillar shaped ZnO nanorods can improve the sensitivity and selectivity of the sensors.

  10. Synthesis of Nanoscale CaO-Al2O3-SiO2-H2O and Na2O-Al2O3-SiO2-H2O Using the Hydrothermal Method and Their Characterization

    Directory of Open Access Journals (Sweden)

    Jingbin Yang

    2017-06-01

    Full Text Available C-A-S-H (CaO-Al2O3-SiO2-H2O and N-A-S-H (Na2O-Al2O3-SiO2-H2O have a wide range of chemical compositions and structures and are difficult to separate from alkali-activated materials. Therefore, it is difficult to analyze their microscopic properties directly. This paper reports research on the synthesis of C-A-S-H and N-A-S-H particles with an average particle size smaller than 300 nm by applying the hydrothermal method. The composition and microstructure of the products with different CaO(Na2O/SiO2 ratios and curing conditions were characterized using XRD, the RIR method, FTIR, SEM, TEM, and laser particle size analysis. The results showed that the C-A-S-H system products with a low CaO/SiO2 ratio were mainly amorphous C-A-S-H gels. With an increase in the CaO/SiO2 ratio, an excess of Ca(OH2 was observed at room temperature, while in a high-temperature reaction system, katoite, C4AcH11, and other crystallized products were observed. The katoite content was related to the curing temperature and the content of Ca(OH2 and it tended to form at a high-temperature and high-calcium environment, and an increase in the temperature renders the C-A-S-H gels more compact. The main products of the N-A-S-H system at room temperature were amorphous N-A-S-H gels and a small amount of sodalite. An increase in the curing temperature promoted the formation of the crystalline products faujasite and zeolite-P. The crystallization products consisted of only zeolite-P in the high-temperature N-A-S-H system and its content were stable above 70%. An increase in the Na2O/SiO2 ratio resulted in more non-bridging oxygen and the TO4 was more isolated in the N-A-S-H structure. The composition and microstructure of the C-A-S-H and N-A-S-H system products synthesized by the hydrothermal method were closely related to the ratio of the raw materials and the curing conditions. The results of this study increase our understanding of the hydration products of alkali

  11. Identification of Shewanella baltica as the most important H2S-producing species during iced storage of danish marine fish

    DEFF Research Database (Denmark)

    Vogel, Birte Fonnesbech; Venkateswaran, K.; Satomi, M.

    2005-01-01

    are important in fish spoilage. More than 500 H2S-producing strains were isolated from iced stored marine fish (cod, plaice, and flounder) caught in the Baltic Sea during winter or summer time. All strains were identified as Shewanella species by phenotypic tests. Different Shewanella species were present...... unchanged (i.e., trimethylamine-N-oxide reduction and H2S production); however, the main H2S-producing organism was identified as S. baltica....

  12. Comparison of UVC/S2O8 2- with UVC/H2O2 in terms of efficiency and cost for the removal of micropollutants from groundwater

    DEFF Research Database (Denmark)

    Antoniou, Maria; Andersen, Henrik Rasmus

    2015-01-01

    ' concentrations were tested with atrazine alone and in the micropollutants' mixture and it was decided to use 11.8mgL(-1) S2O8(2-) and 14.9mgL(-1) H2O2 for further testing since is closer to industrial applications and to minimize the residual oxidant concentration. Changes of the matrix composition......This study compared the UVC/S2O8(2-) system with the more commonly used AOP in water industry, UVC/H2O2, and examined whether the first one can be an economically feasible alternative technology. Atrazine and 4 volatile compounds (methyl tert-butyl ether, cis-dichlorethen, 1,4-dioxane and 1......-through reactor to simulate industrial applications. Initial experiments on the activation of oxidants with a LP lamp indicated that S2O8(2-) is photolysed about 2.3times faster than H2O2 and that the applied treatment times were not sufficient to utilize the majority of the oxidant. The effect of oxidants...

  13. Degassing of CO2, SO2, and H2S associated with the 2009 eruption of Redoubt Volcano, Alaska

    Science.gov (United States)

    Werner, Cynthia; Kelly, Peter J.; Doukas, Michael; Lopez, Taryn; Pfeffer, Melissa; McGimsey, Robert; Neal, Christina

    2013-06-01

    The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions. We report 35 airborne measurements of CO2, SO2, and H2S emission rates that span from October 2008 to August 2010. The magmatic system degassed primarily as a closed system although minor amounts of open system degassing were observed in the 6 months prior to eruption on March 15, 2009 and over 1 year following cessation of dome extrusion. Only 14% of the total CO2 was emitted prior to eruption even though high emissions rates (between 3630 and 9020 t/d) were observed in the final 6 weeks preceding the eruption. A minor amount of the total SO2 was observed prior to eruption (4%), which was consistent with the low emission rates at that time (up to 180 t/d). The amount of the gas emitted during the explosive and dome growth period (March 15-July 1, 2009) was 59 and 66% of the total CO2 and SO2, respectively. Maximum emission rates were 33,110 t/d CO2, 16,650 t/d SO2, and 1230 t/d H2S. Post-eruptive passive degassing was responsible for 27 and 30% of the total CO2 and SO2, respectively. SO2 made up on average 92% of the total sulfur degassing throughout the eruption. Magmas were vapor saturated with a C- and S-rich volatile phase, and regardless of composition, the magmas appear to be buffered by a volatile composition with a molar CO2/SO2 ratio of ~ 2.4. Primary volatile contents calculated from degassing and erupted magma volumes range from 0.9 to 2.1 wt.% CO2 and 0.27-0.56 wt.% S; whole-rock normalized values are slightly lower (0.8-1.7 wt.% CO2 and 0.22-0.47 wt.% S) and are similar to what was calculated for the 1989-90 eruption of Redoubt. Such contents argue that primary arc magmas are rich in CO2 and S. Similar trends between volumes of estimated degassed magma and observed erupted magma during the eruptive period point to primary volatile contents of 1.25 wt.% CO2 and 0.35 wt.% S. Assuming these values, up to 30% additional unerupted magma degassed in the

  14. Recovery of sulfur from residue gases of low H/sub 2/S concentration

    Energy Technology Data Exchange (ETDEWEB)

    Bratzler, K; Doerges, A; Schlauer, J

    1976-01-01

    The Lucas process is intended for reduction of SO/sub 2/ and H/sub 2/S in Claus tail gas or other low-sulfur residue gases to levels below 200 ppm (H/sub 2/S only in traces). In the first stage, all sulfur compounds are burned to SO/sub 2/; in the second stage, a coke reactor reduces SO/sub 3/ and O/sub 2/; and in the third stage, the SO/sub 2/ is absorbed in an aqueous alkali phosphate solution. Concentrated SO/sub 2/ from regeneration of the solution is returned to the Claus plant, or can be catalystically reduced to elemental sulfur. The process was proven out in a semitechnical pilot plant, with satisfactory results as follows: sulfur recovery, 97 to 99.8%; energy consumption per 1,000 cu m feed gas, 2.6 to 3.7 kw-hr plus 860 to 930 MJ heating gas (however, 300 to 350 kg steam was generated); 0.15 kg chemicals; 0.7 to 1.5 kg coke; and a minimal amount of catalyst if sulfur is produced. Investment is only 60 to 80% of that in a 2-stage Claus process, with which the Lucas process is competitive.

  15. Search for the H Dibaryon (S = -2) Using Diffraction Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Ecklund, K.

    2005-04-05

    The observed hadrons are understood as bound states of three quarks (baryons) or of quarks and antiquarks (mesons). To date no six quark bound state other than the loosely bound deuteron has been observed. Quantum Chromodynamics permits other color-singlet bound states of quarks, and a number of phenomenological models extended from the baryon (q{sup 3}) and meson (q{bar q}) sectors predict bound six quark states (q{sup 6}). The most probable candidate is the H dibaryon, composed of two each of the lightest three quarks (udsuds), with quantum numbers J{sup P} = 0{sup +}, I = 0 and S = -2. Its mass would likely be between the deuteron mass and twice the {Lambda} (uds) mass. This dissertation describes a search for the H dibaryon conducted in a neutral beam at the Brookhaven National Laboratory's Alternating Gradient Synchrotron. In the experiment a 24.1 GeV/c proton beam struck a 1.35 interaction length platinum target producing a collimated neutral beam (62 {mu}sr at 65 mrad from the incident proton direction) which propagated through a 18 m vacuum decay tank before entering a double arm spectrometer. Approximately 20 m from the production target a 10 cm (0.15 interaction length) long active scintillator dissociator was placed in the beam.

  16. Structure-based design synthesis of functionalized 3-(5-(s-phenyl)-4H-pyrazol-3-yl)-2H-chromen-2-one motifs and indigenous plant extracts and their antimalarial potential

    Science.gov (United States)

    Olayinka, Ajani; Grace, Olasehinde; Titilope, Dokunmu; Ruth, Diji-Geske; Olabode, Onileere; John, Openibo; Oreoluwa, Oluseye; Tochukwu, Chileke; Ezekiel, Adebiyi

    2018-04-01

    Resistance of the malaria parasite to conventional therapeutic agents calls for increased efforts in antimalarial drug discovery. Current efforts should be targeted at developing safe and affordable new agents to counter the spread of malaria parasites that are resistant to existing therapy. In this study, toxicological and in vivo antiplasmodial properties of 3-(5-(s-phenyl)-4H-pyrazol-3-yl)-42H-chromen-2, Mangifera indica and Tithonia diversifolia in swiss albino mice models, Musmusculus were investigated. 2H-Chromen-2-one also known as coumarin is highly privileged oxygen-containing heterocyclic entity which are present in plant kingdom as secondary metabolites. The maceration technique of crude drug extraction was employed using cold water extraction. Toxicological analysis was carried out using Lorke's method for acute toxicity testing while the chemosuppressive activity was carried out using Peter's four day test on early infection. We also report the synthesis of functionalized 3-(5-(s-phenyl)-4H-pyrazol-3-yl)-2H-chromen-2-one motifs via microwave assisted synthetic approach and isolation of indigenous plant extract in order to investigate their antimalarial efficacy. The condensation reaction of 3-acetylcoumarin with various benzaldehyde derivatives resulted in the formation of 3-[3-acryloyl]-2H-chromen-2-one which was subsequently reaction the hydrazine hydrate via microwave assisted hydrazinolysis to afford the targeted 3-(5-(s-phenyl)-4H-pyrazol-3-yl)-2H-chromen-2-one motifs. The chemical structures were confirmed by analytical data and spectroscopic means such as FT-IR, UV, 1H NMR, 13C NMR and DEPT-135. The microwave assisted reaction was remarkably successful and gave targeted 3-(5-(s-phenyl)-4H-pyrazol-3-yl)-2H-chromen-2-one motifs in higher yields at lesser reaction time compared to conventional heating method. The LD50 of the aqueous extracts of the leaves and stem bark Mangifera indica was established to be ± 707.11 mg/kg b.w., p.o. (body weight

  17. (3aS,7aS-5-[(S-3,3,3-Trifluoro-2-methoxy-2-phenylpropanoyl]-2,3,4,5,6,7-hexahydro-1H-pyrrolo[3,4-c]pyridin-3(2H-one monohydrate

    Directory of Open Access Journals (Sweden)

    Huichun Zhu

    2010-01-01

    Full Text Available rac-Benzyl 3-oxohexahydro-1H-pyrrolo[3,4-c]pyridine-5(6H-carboxylate was separated by chiral chromatography, and one of the enantiomers ([α]22D = +10° was hydrogenated in the presence of Pd/C in methanol, producing octahydro-3H-pyrrolo[3,4-c]pyridin-3-one. The latter was reacted with (2R-3,3,3-trifluoro-2-methoxy-2-phenylpropanoyl chloride [(R-(−-Mosher acid chloride], giving rise to the title compound, C17H19F3N2O3·H2O. The present structure established the absolute configuration of the pyrrolopiperidine fragment based on the known configuration of the (R-Mosher acid chloride. The piperidine ring has a somewhat distorted chair conformation and is cis-fused with the five-membered envelope-shaped ring; the plane of the exocyclic amide bond is approximately orthogonal to the plane of the phenyl ring, making a dihedral angle of 82.31 (3°. The water molecule acts as an acceptor to the proton of the amino group in an N—H...O interaction, and as a double proton donor in O—H...O hydrogen bonds, generating infinite bands along the a axis.

  18. Dynamic Negative Compressibility of Few-Layer Graphene, h-BN, and MoS2

    Science.gov (United States)

    Neves, Bernardo; Barboza, Ana Paula; Chacham, Helio; Oliveira, Camilla; Fernandes, Thales; Martins Ferreira, Erlon; Archanjo, Braulio; Batista, Ronaldo; Oliveira, Alan

    2013-03-01

    We report a novel mechanical response of few-layer graphene, h-BN, and MoS2 to the simultaneous compression and shear by an atomic force microscope (AFM) tip. The response is characterized by the vertical expansion of these two-dimensional (2D) layered materials upon compression. Such effect is proportional to the applied load, leading to vertical strain values (opposite to the applied force) of up to 150%. The effect is null in the absence of shear, increases with tip velocity, and is anisotropic. It also has similar magnitudes in these solid lubricant materials (few-layer graphene, h-BN, and MoS2), but it is absent in single-layer graphene and in few-layer mica and Bi2Se3. We propose a physical mechanism for the effect where the combined compressive and shear stresses from the tip induce dynamical wrinkling on the upper material layers, leading to the observed flake thickening. The new effect (and, therefore, the proposed wrinkling) is reversible in the three materials where it is observed.[2] Financial support from CNPq, Fapemig, Rede Nacional de Pesquisa em Nanotubos de Carbono and INCT-Nano-Carbono

  19. Comparison of biological H2S removal characteristics between a composite packing material with and without functional microorganisms

    Science.gov (United States)

    Zhu, Rencheng; Li, Shunyi; Bao, Xiaofeng; Dumont, Éric

    2017-02-01

    The performances of two identical biofilters, filled with a new composite packing material (named CM-5) embedded with functional microorganisms or sterilized CM-5 without microorganisms, were investigated for H2S treatment. Running parameters in terms of microbial counts, pressure drops, and inlet and outlet H2S concentrations were measured. The results show that the microbial count of the CM-5 was approximately ×105 CFU/g before being filled into the biofilter, while that of the sterilized CM-5 was negligible. The functional microorganisms embedded in CM-5 adapted to the environment containing H2S quickly. In most cases, pressure drops of the CM-5 biofilter were slightly higher than those of the sterilized CM-5 biofilter when the gas flow rate was 0.6-2.5 m3/h. The maximum elimination capacity (EC) of the CM-5 biofilter in treating H2S could reach up to 65 g/(m3·h) when the loading rate (LR) was approximately 80 g/(m3·h). If the LR was much higher, the measured EC showed a slight downward trend. The experimental ECs of biofilters were fitted by two typical dynamic models: the Michaelis-Menten model and the Haldane model. Compared with the Michaelis-Menten model, the Haldane model fit the experimental ECs better for the two biofilters because of the presence of the substrate inhibition behaviour.

  20. Synthesis and characterization of visible-active molybdenum disulfide (2H-MoS{sub 2}) nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Cheah, A. J., E-mail: cheahaijuan@gmail.com; Chiu, W. S., E-mail: w.s.chiu@um.edu.my [Low Dimensional Materials Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Khiew, P. S., E-mail: PoiSim.Khiew@nottingham.edu.my [Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham Malaysia Campus, 43500, Semenyih, Selangor (Malaysia); Radiman, S., E-mail: shahidan@ukm.edu.my; Hamid, M. A. A., E-mail: azmi@ukm.my [School of Applied Physcis, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2015-07-22

    In current study, a novel 2H-MoS{sub 2} nanospheres were successfully synthesized and underwent structural- as well as optical-property characterizations. The MoS{sub 2} were prepared by one pot hydrothermal approach through adopting L-cysteine as environmentally-benignchalcogenide precursor. TEM image shows that the as-synthesized MoS{sub 2} appear to be spherical in shape with size distribution in the range of 120 nm – 180 nm. HRTEM lattice-fringes imaging further elucidate that the interlayer spacing at the edges is equal to be 0.62 nm that correspond to (002) plane stacking. Also, the HRTEM image clearly-illustrate that the internal microstructure of MoS{sub 2} composed of randomly-arrayed alternating layers, which render the postulation that the formation of nanosphere is driven by self-assembly of individual layers into globular morphology. XRD diffractogram that appear to be broad and unresolved reveal the partially crystalline nature of the sample. Optical-absorption spectra depicts the sample is visible active with featureless absorption, which can attribute to indirect transition of the excitions generated. By using Tauc plot, the bandgap energy is determined to be 1.75 eV, which reflect the nanospheres are indeed visible-active nanostructures.

  1. Crystallographic and mutational analyses of cystathionine β-synthase in the H2 S-synthetic gene cluster in Lactobacillus plantarum.

    Science.gov (United States)

    Matoba, Yasuyuki; Yoshida, Tomoki; Izuhara-Kihara, Hisae; Noda, Masafumi; Sugiyama, Masanori

    2017-04-01

    Cystathionine β-synthase (CBS) catalyzes the formation of l-cystathionine from l-serine and l-homocysteine. The resulting l-cystathionine is decomposed into l-cysteine, ammonia, and α-ketobutylic acid by cystathionine γ-lyase (CGL). This reverse transsulfuration pathway, which is catalyzed by both enzymes, mainly occurs in eukaryotic cells. The eukaryotic CBS and CGL have recently been recognized as major physiological enzymes for the generation of hydrogen sulfide (H 2 S). In some bacteria, including the plant-derived lactic acid bacterium Lactobacillus plantarum, the CBS- and CGL-encoding genes form a cluster in their genomes. Inactivation of these enzymes has been reported to suppress H 2 S production in bacteria; interestingly, it has been shown that H 2 S suppression increases their susceptibility to various antibiotics. In the present study, we characterized the enzymatic properties of the L. plantarum CBS, whose amino acid sequence displays a similarity with those of O-acetyl-l-serine sulfhydrylase (OASS) that catalyzes the generation of l-cysteine from O-acetyl-l-serine (l-OAS) and H 2 S. The L. plantarum CBS shows l-OAS- and l-cysteine-dependent CBS activities together with OASS activity. Especially, it catalyzes the formation of H 2 S in the presence of l-cysteine and l-homocysteine, together with the formation of l-cystathionine. The high affinity toward l-cysteine as a first substrate and tendency to use l-homocysteine as a second substrate might be associated with its enzymatic ability to generate H 2 S. Crystallographic and mutational analyses of CBS indicate that the Ala70 and Glu223 residues at the substrate binding pocket are important for the H 2 S-generating activity. © 2017 The Protein Society.

  2. Colloidal lithography nanostructured Pd/PdO x core–shell sensor for ppb level H2S detection

    Science.gov (United States)

    Benedict, Samatha; Lumdee, Chatdanai; Dmitriev, Alexandre; Anand, Srinivasan; Bhat, Navakanta

    2018-06-01

    In this work we report on plasma oxidation of palladium (Pd) to form reliable palladium/palladium oxide (Pd/PdO x ) core–shell sensor for ppb level H2S detection and its performance improvement through nanostructuring using hole-mask colloidal lithography (HCL). The plasma oxidation parameters and the sensor operating conditions are optimized to arrive at a sensor device with high sensitivity and repeatable response for H2S. The plasma oxidized palladium/palladium oxide sensor shows a response of 43.1% at 3 ppm H2S at the optimum operating temperature of 200 °C with response and recovery times of 24 s and 155 s, respectively. The limit of detection (LoD) of the plasma oxidised beam is 10 ppb. We further integrate HCL, a bottom-up and cost-effective process, to create nanodiscs of fixed diameter of 100 nm and varying heights (10, 15 and 20 nm) on 10 nm thin Pd beam which is subsequently plasma oxidized to improve the H2S sensing characteristics. The nanostructured Pd/PdO x sensor with nanodiscs of 100 nm diameter and 10 nm height shows an enhancement in sensing performance by 11.8% at same operating temperature and gas concentration. This nanostructured sensor also shows faster response and recovery times (15 s and 100 s, respectively) compared to the unstructured Pd/PdO x counterpart together with an experimental LoD of 10 ppb and the estimated limit going all the way down to 2 ppb. Material characterization of the fabricated Pd/PdO x sensors is done using UV–vis spectroscopy and x-ray photoemission spectroscopy.

  3. Los profesionales de secundaria, como factores de riesgo en el síndrome de Burnout

    Directory of Open Access Journals (Sweden)

    Giselle León-León

    2011-06-01

    Full Text Available Recibido 21 de julio de 2010 • Aceptado 31 de agosto de 2010 • Corregido 03 de octubre de 2010     Este artículo aborda el síndrome de Bournout, entendido como un trastorno de la adaptación ante el estrés crónico laboral que logra desencadenar síntomas físicos y psicológicos, los cuales dañan significativamente la ejecución profesional de los individuos que prestan servicios, en este particular, el trabajo de los docentes de secundaria, los cuales se describen como vulnerables por atender a adolescentes, quienes requieren mayor comunicación, atención y guía por las característica propias de esa etapa. Además se describen algunos factores que pueden incidir en el docente, desde una perspectiva individual como por ejemplo estrés, rol, edad, estado civil, entre otros. Asímismo factores laborales tales como baja implicación, sobre carga, burocracia, ambiente, consecuencias sobre el individuo y sobre la institución y medidas para prevenirlo.

  4. Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

    DEFF Research Database (Denmark)

    Gersen, Sander; van Essen, Martijn; Darmeveil, Harry

    2017-01-01

    The autoignition and oxidation behavior of CH4/H2S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H2S to methane reduces the autoignition delay time by a factor of 2 at pressures....... A comparison of the flow reactordata to modeling predictions shows satisfactory agreement under stoichiometric conditions, while at very reducing conditions, the model underestimates the consumption of both H2S and CH4. Similar to the RCM experiments, the presence of H2S is predicted to promote oxidation...

  5. Fuel processor integrated H{sub 2}S catalytic partial oxidation technology for sulfur removal in fuel cell power plants

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, T.H.; Berry, D.A.; Lyons, K.D.; Beer, S.K.; Freed, A.D. [U.S. Department of Energy, Morgantown, WV (USA). National Energy Technology Laboratory

    2002-12-01

    H{sub 2}S catalytic partial oxidation technology with an activated carbon catalyst was found to be a promising method for the removal of hydrogen sulfide from fuel cell hydrocarbon feedstocks. Three different fuel cell feedstocks were considered for analysis: sour natural gas, sour effluent from a liquid middle distillate fuel processor and a Texaco O{sub 2}-blown coal-derived synthesis gas. The H{sub 2}S catalytic partial oxidation reaction, its integratability into fuel cell power plants with different hydrocarbon feedstocks and its salient features are discussed. Experimental results indicate that H{sub 2}S concentration can be removed down to the part-per-million level in these plants. Additionally, a power law rate expression was developed and reaction kinetics compared to prior literature. The activation energy for this reaction was determined to be 34.4 kJ/g mol with the reaction being first order in H{sub 2}S and 0.3 order in O{sub 2}. 18 refs., 14 figs., 3 tabs.

  6. Optical and electronic properties of 2 H -Mo S2 under pressure: Revealing the spin-polarized nature of bulk electronic bands

    Science.gov (United States)

    Brotons-Gisbert, Mauro; Segura, Alfredo; Robles, Roberto; Canadell, Enric; Ordejón, Pablo; Sánchez-Royo, Juan F.

    2018-05-01

    Monolayers of transition-metal dichalcogenide semiconductors present spin-valley locked electronic bands, a property with applications in valleytronics and spintronics that is usually believed to be absent in their centrosymmetric (as the bilayer or bulk) counterparts. Here we show that bulk 2 H -Mo S2 hides a spin-polarized nature of states determining its direct band gap, with the spin sequence of valence and conduction bands expected for its single layer. This relevant finding is attained by investigating the behavior of the binding energy of A and B excitons under high pressure, by means of absorption measurements and density-functional-theory calculations. These results raise an unusual situation in which bright and dark exciton degeneracy is naturally broken in a centrosymmetric material. Additionally, the phonon-assisted scattering process of excitons has been studied by analyzing the pressure dependence of the linewidth of discrete excitons observed at the absorption coefficient edge of 2 H -Mo S2 . Also, the pressure dependence of the indirect optical transitions of bulk 2 H -Mo S2 has been analyzed by absorption measurements and density-functional-theory calculations. These results reflect a progressive closure of the indirect band gap as pressure increases, indicating that metallization of bulk Mo S2 may occur at pressures higher than 26 GPa.

  7. Effect of heating and glycation on the allergenicity of 2S albumins (Ara h 2/6 from peanut.

    Directory of Open Access Journals (Sweden)

    Yvonne M Vissers

    Full Text Available Peanut allergy is one of the most common and severe food allergies, and processing is known to influence the allergenicity of peanut proteins. We aimed to establish the effect of heating and glycation on the IgE-binding properties and biological activity of 2S albumins (Ara h 2/6 from peanut.Native Ara h 2/6 was purified from raw peanuts and heated in solution (15 min, 110°C in the presence or absence of glucose. Ara h 2 and 6 were also purified from roasted peanut. Using PBMC and sera from peanut-allergic patients, the cellular proliferative potency and IgE reactivity (reverse EAST inhibition and functionality (basophil degranulation capacity of allergens were assessed. Heating Ara h 2/6 at 110°C resulted in extensive denaturation, hydrolysis and aggregation of the protein, whilst Ara h 2 and 6 isolated from roasted peanut retained its native conformation. Allergen stimulation of PBMC induced proliferation and Th2 cytokine secretion which was unaffected by thermal processing. Conversely, IgE reactivity and functionality of Ara h 2/6 was decreased by heating. Whilst heating-glycation further reduced the IgE binding capacity of the proteins, it moderated their loss of histamine releasing capacity. Ara h 2 and 6 purified from roasted peanut demonstrated the same IgE reactivity as unheated, native Ara h 2/6.Although no effect of processing on T-cell reactivity was observed, heat induced denaturation reduced the IgE reactivity and subsequent functionality of Ara h 2/6. Conversely, Ara h 2 and 6 purified from roasted peanut retained the structure and IgE reactivity/functionality of the native protein which may explain the allergenic potency of this protein. Through detailed molecular study and allergenicity assessment approaches, this work then gives new insights into the effect of thermal processing on structure/allergenicity of peanut proteins.

  8. Mobbing: La violencia psicológica como fuente de estrés laboral

    OpenAIRE

    Fornés Vives, Joana

    2002-01-01

    El mobbing es un fenómeno de alcance personal, laboral e institucional. Puede contextualizarse dentro del ámbito laboral como un tipo de maltrato psicológico o acoso moral. Se ha considerado además como una de las principales fuentes de estrés laboral y su presencia tiene una estrecha vinculación con la aparición de problemas afectivos y relacionales. La indefensión de las víctimas frente a dicho fenómeno hace necesarios planteamientos de contención y estrategias de preven...

  9. A facile stereospecific synthesis of the ( sup 2 H sub 6 )-isopropyl-labelled metoprolol enantiomers from (2R)- and (2S)-glycidyl 3-nitrobenzenesulfonate

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, S.S.; Nelson, W.L. (Washington Univ., Seattle, WA (USA). Dept. of Medicinal Chemistry)

    1990-12-01

    Enantiomers of metoprolol containing six deuterium atoms in the isopropyl methyl groups were prepared in two steps from the sodium salt of 4-(2-methoxyethyl)phenol (3) and the commercially available (2R)-and (2S)-glycidyl 3-nitrobenzenesulfonates ((2R)-2 and (2S)-2). The resulting (2R)- and (2S)-epoxides were opened using ({sup 2}H{sub 6})-isopropylamine. The enantiomeric excesses were 93 and 95% for the deuterated (2R)- and (2S)-enantiomers of metoprolol ((2R)-1 and (2S)-1), respectively, as determined by chiral column HPLC. (author).

  10. Influencia de la concentración del precursor, catalizador y agente reductor en la síntesis de derivados del 2H-INDAZOL.

    OpenAIRE

    Ovalle Pérez, S.; Pérez Rodriguez, N.A.; Elizondo Martínez, P.; Velazoo Soto, M.A.

    2011-01-01

    La importancia de los derivados del2H-indazol es debida a la actividad biológica que han presentado, 10 que ha permitido aplicarlos en la industria farmacéutica, en el sector agrícola entre otros. En este trabajo, primeramente se estudió la influencia de la concentración del N,N'-bis(2-nitrobencil}-1,2-etanodiamina [PJ y diferentes cantidades tanto de agente reductor como de catalizador para favorecer la formación del 2,2' -(etano-I,2-

  11. Protection of White Leghorn chickens by U.S. emergency H5 vaccination against clade 2.3.4.4 H5N2 high pathogenicity avian influenza virus.

    Science.gov (United States)

    Bertran, Kateri; Balzli, Charles; Lee, Dong-Hun; Suarez, David L; Kapczynski, Darrell R; Swayne, David E

    2017-11-01

    During December 2014-June 2015, the U.S. experienced a high pathogenicity avian influenza (HPAI) outbreak caused by clade 2.3.4.4 H5Nx Goose/Guangdong lineage viruses with devastating consequences for the poultry industry. Three vaccines, developed based on updating existing registered vaccines or currently licensed technologies, were evaluated for possible use: an inactivated reverse genetics H5N1 vaccine (rgH5N1) and an RNA particle vaccine (RP-H5), both containing the hemagglutinin gene of clade 2.3.4.4 strain, and a recombinant herpesvirus turkey vectored vaccine (rHVT-H5) containing the hemagglutinin gene of clade 2.2 strain. The efficacy of the three vaccines, alone or in combination, was assessed in White Leghorn chickens against clade 2.3.4.4 H5N2 HPAI virus challenge. In Study 1, single (rHVT-H5) and prime-boost (rHVT-H5+rgH5N1 or rHVT-H5+RP-H5) vaccination strategies protected chickens with high levels of protective immunity and significantly reduced virus shedding. In Study 2, single vaccination with either rgH5N1 or RP-H5 vaccines provided clinical protection in adult chickens and significantly reduced virus shedding. In Study 3, double rgH5N1 vaccination protected adult chickens from clinical signs and mortality when challenged 20weeks post-boost, with high levels of long-lasting protective immunity and significantly reduced virus shedding. These studies support the use of genetically related vaccines, possibly in combination with a broad protective priming vaccine, for emergency vaccination programs against clade 2.3.4.4 H5Nx HPAI virus in young and adult layer chickens. Published by Elsevier Ltd.

  12. Composition and structural study of solution-processed Zn(S,O,OH) thin films grown using H{sub 2}O{sub 2} based deposition route

    Energy Technology Data Exchange (ETDEWEB)

    Buffière, M., E-mail: marie.buffiere@imec.be [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); 44Solar, 14 rue Kepler, 44240 La Chapelle-sur-Erdre (France); Gautron, E. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Hildebrandt, T. [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP)-UMR 7174 EDF-CNRS-ENSCP, 6 quai Watier-78401 Chatou Cedex (France); Harel, S.; Guillot-Deudon, C.; Arzel, L. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Naghavi, N. [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP)-UMR 7174 EDF-CNRS-ENSCP, 6 quai Watier-78401 Chatou Cedex (France); Barreau, N. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Kessler, J. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); 44Solar, 14 rue Kepler, 44240 La Chapelle-sur-Erdre (France)

    2013-05-01

    Recent results have revealed that the low deposition time issue of chemical bath deposited (CBD) Zn(S,O,OH) buffer layer used in Cu(In,Ga)Se{sub 2} (CIGSe) solar cells could be resolved using H{sub 2}O{sub 2} as an additive in the chemical bath solution. Although the use of this additive does not hinder the electrical properties of the resulting Zn(S,O,OH)-buffered CIGSe solar cells, the impact of H{sub 2}O{sub 2} on the Zn(S,O,OH) properties remains unclear. The present contribution aims at determining the chemical composition and the microstructure of Zn(S,O,OH) film deposited by CBD using the alternative deposition bath containing the standard zinc sulfate, thiourea, ammonia but also H{sub 2}O{sub 2} additive. Both X-ray photoemission spectroscopy and energy dispersive X-ray spectroscopy analyses reveal higher sulfur content in alternatively deposited Zn(S,O,OH), since the first step growth of the layer. According to transmission electron microscopy analyses, another consequence of the higher deposition rate achieved when adding H{sub 2}O{sub 2} in the bath is the modification of the absorber/buffer interface. This could be explained by the enhancement of the cluster growth mechanism of the layer. - Highlights: ► The Zn(S,O,OH) layer composition can vary with the chemical bath process used. ► The alternative process leads to a faster incorporation of sulfur in the layer. ► No ZnS epitaxial layer has been found at absorber/alternative buffer interface. ► The use of H{sub 2}O{sub 2} enhances the cluster-by-cluster growth mechanism.

  13. Direct measurements of rate constants for the reactions of CH3 radicals with C2H6, C2H4, and C2H2 at high temperatures.

    Science.gov (United States)

    Peukert, S L; Labbe, N J; Sivaramakrishnan, R; Michael, J V

    2013-10-10

    The shock tube technique has been used to study the reactions CH3 + C2H6 → C2H4 + CH4 + H (1), CH3 + C2H4 → Products + H (2), and CH3 + C2H2 → Products + H (3). Biacetyl, (CH3CO)2, was used as a clean high temperature thermal source for CH3-radicals for all the three reactions studied in this work. For reaction 1, the experiments span a T-range of 1153 K ≤ T ≤ 1297 K, at P ~ 0.4 bar. The experiments on reaction 2 cover a T-range of 1176 K ≤ T ≤ 1366 K, at P ~ 1.0 bar, and those on reaction 3 a T-range of 1127 K ≤ T ≤ 1346 K, at P ~ 1.0 bar. Reflected shock tube experiments performed on reactions 1-3, monitored the formation of H-atoms with H-atom Atomic Resonance Absorption Spectrometric (ARAS). Fits to the H-atom temporal profiles using an assembled kinetics model were used to make determinations for k1, k2, and k3. In the case of C2H6, the measurements of [H]-atoms were used to derive direct high-temperature rate constants, k1, that can be represented by the Arrhenius equation k1(T) = 5.41 × 10(-12) exp(-6043 K/T) cm(3) molecules(-1) s(-1) (1153 K ≤ T ≤ 1297 K) for the only bimolecular process that occurs, H-atom abstraction. TST calculations based on ab initio properties calculated at the CCSD(T)/CBS//M06-2X/cc-pVTZ level of theory show excellent agreement, within ±20%, of the measured rate constants. For the reaction of CH3 with C2H4, the present rate constant results, k2', refer to the sum of rate constants, k(2b) + k(2c), from two competing processes, addition-elimination, and the direct abstraction CH3 + C2H4 → C3H6 + H (2b) and CH3 + C2H4 → C2H2 + H + CH4 (2c). Experimental rate constants for k2' can be represented by the Arrhenius equation k2'(T) = 2.18 × 10(-10) exp(-11830 K/T) cm(3) molecules(-1) s(-1) (1176 K ≤ T ≤ 1366 K). The present results are in excellent agreement with recent theoretical predictions. The present study provides the only direct measurement for the high-temperature rate constants for these channels

  14. Dual layer hollow fiber sorbents for trace H2S removal from gas streams

    KAUST Repository

    Bhandari, Dhaval A.; Bessho, Naoki; Koros, William J.

    2013-01-01

    Hollow fiber sorbents are pseudo monolithic materials with potential use in various adsorption based applications. Dual layer hollow fiber sorbents have the potential to allow thermal regeneration without direct contact of the regeneration fluid with the sorbent particles. This paper considers the application of dual layer hollow fiber sorbents for a case involving trace amounts of H2S removal from a simulated gas stream and offers a comparison with single layer hollow fiber sorbents. The effect of spin dope composition and core layer zeolite loading on the gas flux, H2S transient sorption capacity and pore structure are also studied. This work can be used as a guide to develop and optimize dual layer hollow fiber sorbent properties beyond the specific example considered here. © 2013 Elsevier Ltd.

  15. Dual layer hollow fiber sorbents for trace H2S removal from gas streams

    KAUST Repository

    Bhandari, Dhaval A.

    2013-05-01

    Hollow fiber sorbents are pseudo monolithic materials with potential use in various adsorption based applications. Dual layer hollow fiber sorbents have the potential to allow thermal regeneration without direct contact of the regeneration fluid with the sorbent particles. This paper considers the application of dual layer hollow fiber sorbents for a case involving trace amounts of H2S removal from a simulated gas stream and offers a comparison with single layer hollow fiber sorbents. The effect of spin dope composition and core layer zeolite loading on the gas flux, H2S transient sorption capacity and pore structure are also studied. This work can be used as a guide to develop and optimize dual layer hollow fiber sorbent properties beyond the specific example considered here. © 2013 Elsevier Ltd.

  16. Room temperature H{sub 2}S gas sensing characteristics of platinum (Pt) coated porous alumina (PoAl) thick films

    Energy Technology Data Exchange (ETDEWEB)

    More, P.S., E-mail: p_smore@yahoo.co.in [Department of Physics, Institute of Science, Mumbai 400 032 (India); Raut, R.W. [Department of Botany, Institute of Science, Mumbai 400 032 (India); Ghuge, C.S. [Department of Physics, Institute of Science, Mumbai 400 032 (India)

    2014-02-14

    The study reports H{sub 2}S gas sensing characteristics of platinum (Pt) coated porous alumina (PoAl) films. The porous alumina (PoAl) thick layers were formed in the dark on aluminum substrates using an electrochemical anodization method. Thin semitransparent platinum (Pt) films were deposited on PoAl samples using chemical bath deposition (CBD) method. The films were characterized using energy dispersive X-ray analysis (EDAX) and scanning electron microscopy (SEM). The thicknesses of coated and bare films were measured using ellipsometry. The sensing properties such as sensitivity factor (S.F.), response time, recovery time and repeatability were measured using a static gas sensing system for H{sub 2}S gas. The EDAX studies confirmed the purity of Pt–PoAl film and indicated the formation of pure platinum (Pt) phase. The ellipsometry studies revealed the thickness of PoAl layer of about 15–17 μm on aluminum substrates. The SEM studies demonstrated uniform distribution of spherical pores with a size between 0.250 and 0.500 μm for PoAl film and nearly spherical platinum particles with average particle size ∼100 nm for Pt–PoAl film. The gas-sensing properties of these samples were studied in a home-built static gas characterization system. The H{sub 2}S gas sensing properties of Pt–PoAl at 1000 ppm of H{sub 2}S gave maximum sensitivity factor (S.F.) = 1200. The response time and recovery time were found to be 2–3 min and ∼1 min respectively. Further, the measurement of H{sub 2}S gas sensing properties clearly indicated the repeatability of gas sensing response of Pt–PoAl film. The present study indicated the significant potential of Pt coated PoAl films for H{sub 2}S gas sensing applications in diverse areas. - Highlights: • Electrochemical anodization, cheap and effective method for fabrication of PoAl. • Chemical bath deposition, a simple and effective method for deposition of Pt on PoAl. • A nano-composite film sensor with high sensitivity

  17. Pregnancy Augments VEGF-Stimulated In Vitro Angiogenesis and Vasodilator (NO and H2S) Production in Human Uterine Artery Endothelial Cells.

    Science.gov (United States)

    Zhang, Hong-Hai; Chen, Jennifer C; Sheibani, Lili; Lechuga, Thomas J; Chen, Dong-Bao

    2017-07-01

    Augmented uterine artery (UA) production of vasodilators, including nitric oxide (NO) and hydrogen sulfide (H2S), has been implicated in pregnancy-associated and agonist-stimulated rise in uterine blood flow that is rate-limiting to pregnancy health. Developing a human UA endothelial cell (hUAEC) culture model from main UAs of nonpregnant (NP) and pregnant (P) women for testing a hypothesis that pregnancy augments endothelial NO and H2S production and endothelial reactivity to vascular endothelial growth factor (VEGF). Main UAs from NP and P women were used for developing hUAEC culture models. Comparisons were made between NP- and P-hUAECs in in vitro angiogenesis, activation of cell signaling, expression of endothelial NO synthase (eNOS) and H2S-producing enzymes cystathionine β-synthase (CBS) and cystathionine γ-lyase, and NO/H2S production upon VEGF stimulation. NP- and P-hUAECs displayed a typical cobblestone-like shape in culture and acetylated low-density lipoprotein uptake, stained positively for endothelial and negatively for smooth muscle markers, maintained key signaling proteins during passage, and had statistically significant greater eNOS and CBS proteins in P- vs NP-hUAECs. Treatment with VEGF stimulated in vitro angiogenesis and eNOS protein and NO production only in P-hUEACs and more robust cell signaling in P- vs NP-hUAECs. VEGF stimulated CBS protein expression, accounting for VEGF-stimulated H2S production in hUAECs. Comparisons between NP- and P-hUAECs reveal that pregnancy augments VEGF-stimulated in vitro angiogenesis and NO/H2S production in hUAECs, showing that the newly established hUAEC model provides a critical in vitro tool for understanding human uterine hemodynamics. Copyright © 2017 Endocrine Society

  18. Degassing of CO2, SO2, and H2S associated with the 2009 eruption of Redoubt Volcano, Alaska

    Science.gov (United States)

    Werner, Cynthia A.; Kelly, Peter; Doukas, Michael P.; Lopez, Taryn; Pfeffer, Melissa; McGimsey, Robert G.; Neal, Christina

    2013-01-01

    The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions. We report 35 airborne measurements of CO2, SO2, and H2S emission rates that span from October 2008 to August 2010. The magmatic system degassed primarily as a closed system although minor amounts of open system degassing were observed in the 6 months prior to eruption on March 15, 2009 and over 1 year following cessation of dome extrusion. Only 14% of the total CO2 was emitted prior to eruption even though high emissions rates (between 3630 and 9020 t/d) were observed in the final 6 weeks preceding the eruption. A minor amount of the total SO2 was observed prior to eruption (4%), which was consistent with the low emission rates at that time (up to 180 t/d). The amount of the gas emitted during the explosive and dome growth period (March 15–July 1, 2009) was 59 and 66% of the total CO2and SO2, respectively. Maximum emission rates were 33,110 t/d CO2, 16,650 t/d SO2, and 1230 t/d H2S. Post-eruptive passive degassing was responsible for 27 and 30% of the total CO2 and SO2, respectively. SO2 made up on average 92% of the total sulfur degassing throughout the eruption. Magmas were vapor saturated with a C- and S-rich volatile phase, and regardless of composition, the magmas appear to be buffered by a volatile composition with a molar CO2/SO2 ratio of ~ 2.4. Primary volatile contents calculated from degassing and erupted magma volumes range from 0.9 to 2.1 wt.% CO2 and 0.27–0.56 wt.% S; whole-rock normalized values are slightly lower (0.8–1.7 wt.% CO2 and 0.22–0.47 wt.% S) and are similar to what was calculated for the 1989–90 eruption of Redoubt. Such contents argue that primary arc magmas are rich in CO2 and S. Similar trends between volumes of estimated degassed magma and observed erupted magma during the eruptive period point to primary volatile contents of 1.25 wt.% CO2 and 0.35 wt.% S. Assuming these values, up to 30% additional

  19. On-line H2S monitoring using near-infrared tunable diode laser spectroscopy

    International Nuclear Information System (INIS)

    Partin, J.K.; Jeffrey, C.L.

    1998-01-01

    The purpose of this project is to evaluate and demonstrate the technique of frequency-modulated, tunable diode laser spectroscopy for the monitoring of H 2 S gas in geothermal plant emissions. The geothermal power industry has an interest in the development of real-time techniques for monitoring these emissions, since improved measurement capabilities could lead to considerable cost savings through the optimization of the chemicals used for abatement. There are several locations throughout the plant at which this measurement could be performed. They vary from the main stream line which operates at a temperature of about 350 F (175 C) and a pressure of 100 psig to the cooling stack with a temperature of 80--100 F (27--38 C) at ambient pressure. Gas concentrations range from 0.1 ppm to 1,000's of ppms. The technical goal of this effort was to perform a series of scoping experiments to determine the effect of elevated pressure, temperature and water vapor on the sensitivity of this spectroscopic technique for the detection of H 2 S. The results of these experiments are presented, and the deployment options and system designs are discussed

  20. Josep Beuys : el arte como creencia y como salvación

    Directory of Open Access Journals (Sweden)

    María López Ruido

    1995-01-01

    Full Text Available Joseph Beuys, nacido en Cléveris (Renania del Norte-Westfalia en 1921 y faliecido en Dusseldorf en 1986, posee una obra madura casi desde un primer momento. Superficialmente podríamos verla como el canto a sí mismo de un gran narcisista, donde sus experiencias y su persona son los grandes protagonistas. En una lectura más profunda, estos hechos personales no son más que el medio para ir más allá del yo y dar lugar a una creación plástica de trascendencia social. Tras la 2- Guerra Mundial, en la que lucha como piloto de la Luftwaffe, estudia en la Academia de Bellas Artes de Dusseldorf. Será a partir de los años 60 cuando encontremos al auténtico Beuys, escultor objetual e instalador, el creador de la plástica social, y desde sus contactos con Fluxus en 1962, el Beuys accionista. En los 70, se nos presenta el artista más claramente politizado. La educación, la incidencia social del arte, el arte como «tercera vía o vía alternativa» entre socialismo y capitalismo, la ecología serán sus materiales de trabajo.

  1. (2aR*,5S*,6aS*,8aS*,E-Ethyl 5-hydroxy-7,7,8a-trimethyl-8-oxo-2,2a,6,6a,7,8,8a,8b-octahydro-1H-pentaleno[1,6-bc]oxepine-4-carboxylate

    Directory of Open Access Journals (Sweden)

    Goverdhan Mehta

    2012-12-01

    Full Text Available The title compound, C17H24O5, featuring a 2-carbethoxy-3-oxepanone unit in its intramolecularly O—H...O hydrogen-bonded enol form, was obtained via [(CF3CO22Rh]2-catalysed intramolecular O—H bond insertion in the α-diazo-ω-hydroxy-β-ketoester, ethyl 4-[(1S,3aS,6R,6aS-6-hydroxy-2,2,3a-trimethyl-3-oxo-octahydropentalen-1-yl]-2-diazo-3-oxobutanoate. The seven-membered oxacyclic ring, thus constructed on a cis-fused diquinane platform, was found to adopt a distorted boat–sofa conformation.

  2. 2H(d,p)3H and 2H(d,n)3He reactions at sub-coulomb energies

    International Nuclear Information System (INIS)

    Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Spartá, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.

    2012-01-01

    The 2 H( 3 He,p 3 H) 1 H and 2 H( 3 He,n 3 He) 1 H processes have been measured in quasi free kinematics to investigate for the first time the 2 H(d,p) 3 H and 2 H(d,n) 3 He reactions by means of the Trojan Horse Method. The 3 He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4±1.8 MeVb for 3 H+p and 60.1±1.9 MeVb for 3 He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

  3. Isoreticular rare earth fcu-MOFs for the selective removal of H 2 S from CO 2 containing gases

    KAUST Repository

    Bhatt, Prashant; Belmabkhout, Youssef; Assen, Ayalew Hussen Assen; Weselinski, Lukasz Jan; Jiang, Hao; Cadiau, Amandine; Xue, Dongxu; Eddaoudi, Mohamed

    2017-01-01

    . Markedly, RE-fcu-MOFs, having different pore apertures sizes in the range of 4.7-6.0 Å and different functionalities, showed excellent properties for the removal of H2S from CO2 and CH4 containing gases such as natural gas, biogas and landfill gas. A series

  4. Prediction of Mechanism and Thermochemical Properties of O3 + H2S Atmospheric Reaction

    Directory of Open Access Journals (Sweden)

    Morteza Vahedpour

    2013-01-01

    Full Text Available Ozone and hydrogen sulfide reaction mechanism including a complex was studied at the B3LYP/6-311++G(3df,3pd and CCSD/6-311++G(3df,3pd//B3LYP/6-311++G(3df,3pd levels of computation. The interaction between sulfur atom of hydrogen sulfide and terminal oxygen atom of ozone produces a stable H2S-O3 complex with no barrier. With the decomposition of this complex, four possible product channels have been found. Intrinsic reaction coordinate, topological analyses of atom in molecule, and vibrational frequency calculation have been used to confirm the suggested mechanism. Thermodynamic data at T = 298.15 K and the atmospheric pressure have been calculated. The results show that the production of H2O + SO2 is the main reaction channel with ΔG° = −645.84 kJ/mol. Rate constants of H2S + O3 reaction show two product channels, SO2 + H2O and HSO + HOO, which compete with each other based on the temperature.

  5. Preliminary results on effect of H2S on P265GH commercial material for natural gases and petroleum transportation

    Science.gov (United States)

    Zaharia, Marius Gabriel; Stanciu, Sergiu; Cimpoesu, Ramona; Ionita, Iulian; Cimpoesu, Nicanor

    2018-04-01

    A commercial Fe-C material (P265GH) used for natural gas delivery and transportation systems was analyzed in H2S atmosphere in order to establish the corrosion resistance. In most of the industrial processes for gas purification the corrosion rate is speed up by the presence of sulphur (S) especially as ions (HS-, SO32-) or different species like H2S. The H2S (hydrogen sulphide) is, beside a very toxic compound, a very active element in the acceleration of metallic materials deterioration. For experiments we used a three electrodes cell with Na2SO4 + Na2S solution at pH 3 for two different temperatures, room temperature ∼ 25 °C (sample 1) and at 60 (sample 2) ±1 °C in order to realize EIS (electrochemical impedance spectroscopy) and potentiodynamic polarization. After electro-chemical tests and corrosion resistance characterisation the material surface was analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS).

  6. The nitrogen acceptor in 2H-Polytype synthetic MoS2. Frequency and temperature dependent ESR analysis

    International Nuclear Information System (INIS)

    Schoenaers, Ben; Stesmans, Andre; Afanas'ev, Valery V.

    2017-01-01

    In extending on recent electron spin resonance (ESR) work which has revealed the N acceptor (N substituting for S site) in 2H-polytype bulk synthetic MoS 2 , the dopant is extensively analyzed in terms of its frequency, temperature (T), and magnetic field B angular dependent ESR spectral characteristics. For B parallel c-axis, the multi-frequency analysis confirms the ESR spectrum as being composed of a 14 N hyperfine (hf) triplet with hf splitting constant A parallel = 14.7 ± 0.2 G (B parallel c-axis) and making up ∼74% of the total spectrum intensity, superimposed on a central line centered at about equal g-value [g parallel = 2.032(2)]. The presence of the latter signal, points to some non-uniformity in dopant distribution, that is, clustering, with about ∼26% of the total N response not originating from N incorporated in the preferred ''isolated'' dopant configuration. Angular dependent measurements reveal distinct anisotropy of the hf matrix, whereas ESR probing over a wide T-range exposes drastic signal broadening with increasing T above ∼150 K. Detailed study of the N acceptor signal intensity versus T at Q-band reveals an activation energy E a = 50 ± 10 meV, herewith consolidating the value reported initially. Besides unveiling the S-site substitutional N impurity as an appropriate p-type dopant for MoS 2 , the total of the ESR work establishes a basic frame of the N acceptor ESR characteristics, giving way for further in-depth theoretical perusal. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Low-temperature solid-state preparation of ternary CdS/g-C3N4/CuS nanocomposites for enhanced visible-light photocatalytic H2-production activity

    Science.gov (United States)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

    2017-01-01

    Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C3N4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C3N4/CuS composite exhibits a high visible-light photocatalytic H2-production rate of 57.56 μmol h-1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na2S/Na2SO3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C3N4/CuS composites show the enhanced visible-light photocatalytic H2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C3N4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H2-production activity.

  8. Synthesis of 9H-Indeno [1, 2-b] Pyrazine and 11H-Indeno [1, 2-b ...

    African Journals Online (AJOL)

    NICO

    Synthesis of 9H-Indeno [1, 2-b] Pyrazine and. 11H-Indeno [1, 2-b] Quinoxaline Derivatives in. One-step Reaction from 2-Bromo-4-chloro-1-indanone. S. Jasouri1,2, J. Khalafy1,*, M. Badali2 and R.H. Prager3. 1Department of Chemistry, Urmia University, Urmia 57154, Iran. 2Daana Pharmaceutical Co., P.O. Box 5181, Tabriz ...

  9. Removal of H/sub 2/S from hot gas in the presence of Cu-containing sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Kyotani, T.; Kawashima, H.; Tomita, A.; Palmer, A.; Furimsky, E.

    1989-01-01

    Three solids containing Cu oxides were tested as sorbents for H/sub 2/S removal from hot gas at 600 degrees C. The formation of a surface layer of sulphides on pellet exterior affected Cu utilization for the sorbent prepared from Cu oxides alone. This improved for the sorbent prepared by impregnation of zeolite with Cu oxides, although complete utilization of Cu was not achieved. The combination of Cu oxides with SiO/sub 2/ gave the most efficient sorbent. Oxidation of H/sub 2/S to SO/sub 2/ on admission of hot gas to the fixed bed was a common observation for all sorbents. The addition of steam to hot gas suppressed the SO/sub 2/ formation. 9 refs., 6 figs., 4 tabs.

  10. Laboratory, semi-pilot and room scale study of nitrite and molybdate mediated control of H(2)S emission from swine manure.

    Science.gov (United States)

    Moreno, Lyman; Predicala, Bernardo; Nemati, Mehdi

    2010-04-01

    The effects of manure age on emission of H(2)S and required level of nitrite or molybdate to control these emissions were investigated in the present work. Molybdate mediated control of H(2)S emission was also studied in semi-pilot scale open systems, and in specifically designed chambers which simulated swine production rooms. With fresh 1-, 3- and 6-month old manures average H(2)S concentration in the headspace gas of the closed systems were 4856+/-460, 3431+/-208, 1037+/-98 ppm and non-detectable, respectively. Moreover, the level of nitrite or molybdate required to control the emission of H(2)S decreased as manure age increased. In the semi-pilot scale open system and chambers, average H(2)S concentration at the surface of agitated fresh manure were 831+/-26 and 88.4+/-5.7 ppm, respectively. Furthermore, 0.1-0.25 mM molybdate was sufficient to control the emission of H(2)S. A cost study for an average size swine operation showed that the cost of treatment with molybdate was less than 1% of the overall production cost for each market hog. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. 5-[(E-(2-Hydroxybenzylideneamino]-1H-1,3-benzimidazole-2(3H-thione

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2011-01-01

    Full Text Available There are two molecules in the asymmetric unit of the title compound, C14H11N3OS. In each, the benzimidazole ring system is essentially planar, with maximum deviations of 0.010 (2 and 0.006 (2 Å, and makes dihedral angles of 8.70 (9 and 13.75 (8°, respectively, with the hydroxy-substituted benzene rings. Each molecule adopts an E configuration about the central C=N double bond. In the crystal, the two independent molecules are connected via intermolecular N—H...S hydrogen bonds, forming dimers. Furthermore, the dimers are connected by N—H...O hydrogen bonds into molecular ribbons along the c axis. There is an intramolecular O—H...N hydrogen bond in each molecule, which generates an S(6 ring motif.

  12. Sediment Resuspension and Deposition on Seagrass Leaves Impedes Internal Plant Aeration and Promotes Phytotoxic H2S Intrusion.

    Science.gov (United States)

    Brodersen, Kasper E; Hammer, Kathrine J; Schrameyer, Verena; Floytrup, Anja; Rasheed, Michael A; Ralph, Peter J; Kühl, Michael; Pedersen, Ole

    2017-01-01

    HIGHLIGHTS: Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H 2 S. Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended particles onto seagrass leaves potentially impeding gas exchange with the surrounding water. We used microsensors to determine O 2 fluxes and diffusive boundary layer (DBL) thickness on leaves of the seagrass Zostera muelleri with and without fine sediment particles, and combined these laboratory measurements with in situ microsensor measurements of tissue O 2 and H 2 S concentrations. Net photosynthesis rates in leaves with fine sediment particles were down to ~20% of controls without particles, and the compensation photon irradiance increased from a span of 20-53 to 109-145 μmol photons m -2 s -1 . An ~2.5-fold thicker DBL around leaves with fine sediment particles impeded O 2 influx into the leaves during darkness. In situ leaf meristematic O 2 concentrations of plants exposed to fine sediment particles were lower than in control plants and exhibited long time periods of complete meristematic anoxia during night-time. Insufficient internal aeration resulted in H 2 S intrusion into the leaf meristematic tissues when exposed to sediment resuspension even at relatively high night-time water-column O 2 concentrations. Fine sediment particles that settle on seagrass leaves thus negatively affect internal tissue aeration and thereby the plants' resilience against H 2 S intrusion.

  13. One-electron capture into Li-like autoionising N4+ (1s2ln'l') configurations by metastable N5+ (1s2s3S) multicharged ions in collisions with He and H2, observed by electron spectrometry at 3.4 keV amu-1

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.

    1985-01-01

    One-electron capture into N 4+ (1s2ln'l') configurations, with n'=2 to 4, has been observed by electron spectrometry when a N 5+ (1s2s 3 S) multicharged ion beam encounters an He or H 2 target, at low collision velocity (upsilon=0.37 au) within single-collision conditions. Contributions of other 1s2l metastable states and of the 1s 2 ground state may be disregarded. A small indication of two-electron capture by 1s2s 3 S ions into (1s2s 3 S)3l3l' configurations is also seen. (author)

  14. Practical criterion for the determination of translation factors. II. Application to He2++H(1s) collisions

    International Nuclear Information System (INIS)

    Errea, L.F.; Gomez-Llorente, J.M.; Mendez, L.; Riera, A.

    1985-01-01

    An illustration is reported on the use of the Euclidean norm as a criterion of the quality of translation factors in the molecular model of atomic collisions. The relation between our norm and the deviation vector of Chang and Rapp [J. Chem. Phys. 59, 572 (1973)], and the computational simplicity of the calculation and minimization of the former quantity, are very appealing features of our approach. To show how the norm method can be applied, the He 2+ +H(1s)→He + (2s,2p )+H + reaction is treated

  15. CO2 como refrigerante: del pasado al futuro CO2 as refrigerant: from the past to future

    Directory of Open Access Journals (Sweden)

    Juan Manuel Belman Flores

    2013-05-01

    Full Text Available En años recientes y debido a la problemática que ha originado el calentamiento mundial, en el campo de la refrigeración y climatización se ha incrementado el interés por utilizar refrigerantes naturales e hidrocarburos con bajo potencial de calentamiento mundial, este es el caso de la utilización del CO2 como fluido frigorígeno que ha sido visto como una alter­nativa adecuada a los actuales refrigerantes en la comunidad científica. Hoy en día, el CO2 cada vez está retomando presencia en el campo de la refrigeración y climatización a nivel internacional, así pues, el presente trabajo tiene la finalidad de dar a conocer su potencial como refrigerante natural, las causas por las cuales este fluido fue relevado momentánea­mente por refrigerantes clorofluorocarbonados y su renacer en pleno siglo XXI. Además, se plantea su aplicación en la generación de frío en nuestro país mediante la tecnología de compresión de vapor basado en ciclo transcrítico.  In recent years, and due to problems resulting from global warming, interest has grown in the fields of refrigeration and air conditioning, specifically regarding the use of natural refrigerants and hydrocarbons with low potential for global warming. Such is the case of the use of CO2 as a cold fluid, which has been considered in the scientific community as an adequate alternative to common refrigerants. Nowadays, the use of CO2 in the areas of refrigeration and air conditioning has been recognized at international levels. Therefore, this work aims to show its potential as a natural refrigerant, the causes why this fluid was temporarily replaced by chlorofluorocarbon refrigerants, and its reappearance in the XXI century. It also proposes the use of CO2 in air conditioning in our country by using vapor compression technology, based on the transcritical cycle.

  16. (Solid + liquid) phase equilibria of (Ca(H2PO2)2 + CaCl2 + H2O) and (Ca(H2PO2)2 + NaH2PO2 + H2O) ternary systems at T = 323.15 K

    International Nuclear Information System (INIS)

    Cao, Hong-yu; Zhou, Huan; Bai, Xiao-qin; Ma, Ruo-xin; Tan, Li-na; Wang, Jun-min

    2016-01-01

    Graphical abstract: Solubility diagram of the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system at T = (323.15 and 298.15) K. - Highlights: • Phase diagrams of Ca 2+ -H 2 PO 2 − -Cl − -H 2 O, Ca 2+ -Na + -H 2 PO 2 − -H 2 O at 323.15 K were obtained. • Incompatible double salt of NaCa(H 2 PO 2 ) 3 in Ca 2+ -Na + -H 2 PO 2 − -H 2 O system was determined. • Density diagram of the corresponding liquid were simultaneously measured. - Abstract: Calcium hypophosphite has been widely used as an anti-corrosive agent, flame retardant, fertilizer, assistant for Ni electroless plating, and animal nutritional supplement. High purity calcium hypophosphite can be synthesized via the replacement reaction of sodium hypophosphite and calcium chloride. In this work, the (solid + liquid) phase equilibria of (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) and (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) ternary systems at T = 323.15 K were studied experimentally via the classical isothermal solubility equilibrium method, and the phase diagrams for these two systems were obtained. It was found that two solid salts of CaCl 2 ·2H 2 O and Ca(H 2 PO 2 ) 2 exist in the (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) system, and three salts of Ca(H 2 PO 2 ) 2 , NaH 2 PO 2 ·H 2 O and one incompatible double salt, NaCa(H 2 PO 2 ) 3 occur in the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system.

  17. Sulfur bonding in MoS2 and Co-Mo-S structures

    DEFF Research Database (Denmark)

    Byskov, Line Sjolte; Hammer, Bjørk; Nørskov, Jens Kehlet

    1997-01-01

    The structure and bonding in small MoS2 structures with and without Co is studied theoretically using self-consistent density functional theory with a non-local exchange-correlation energy. The structures model the catalysts used extensively in hydrotreating. We study in detail the structure...... study the energy required to form sulfur vacancies, which are believed to be the active sites for many hydrotreating reactions. The presence of Co atoms at the edges is shown to lead to a significant lowering of the metal-sulfur binding energy. This imposes an increase in the concentration of active...

  18. Performance evaluation of poly-urethane foam packed-bed chemical scrubber for the oxidative absorption of NH3 and H2S gases.

    Science.gov (United States)

    Nisola, Grace M; Valdehuesa, Kris Niño G; Anonas, Alex V; Ramos, Kristine Rose M; Lee, Won-Keun; Chung, Wook-Jin

    2018-01-02

    The feasibility of open-pore polyurethane (PU) foam as packing material for wet chemical scrubber was tested for NH 3 and H 2 S removals. The foam is inexpensive, light-weight, highly porous (low pressure drop) and provides large surface area per unit volume, which are desirable properties for enhanced gas/liquid mass transfer. Conventional HCl/HOCl (for NH 3 ) and NaOH/NaOCl (for H 2 S) scrubbing solutions were used to absorb and oxidize the gases. Assessment of the wet chemical scrubbers reveals that pH and ORP levels are important to maintain the gas removal efficiencies >95%. A higher re-circulation rate of scrubbing solutions also proved to enhance the performance of the NH 3 and H 2 S columns. Accumulation of salts was confirmed by the gradual increase in total dissolved solids and conductivity values of scrubbing solutions. The critical elimination capacities at >95% gas removals were found to be 5.24 g NH 3 -N/m 3 -h and 17.2 g H 2 S-S/m 3 -h at an empty bed gas residence time of 23.6 s. Negligible pressure drops (scrubbers for NH 3 and H 2 S removals from high-volume dilute emissions.

  19. Study of the sensitivity of the H.E.S.S.2 experiment below 300 GeV and indirect search of dark matter with the H.E.S.S. Data

    International Nuclear Information System (INIS)

    Masbou, J.

    2010-09-01

    The H.E.S.S. telescope (High Energy Stereoscopic System) is an experiment of four imaging Cherenkov Telescope looking on gamma rays from 100 GeV to 100 TeV. In 2012, the experiment will be upgraded in a second phase with a fifth telescope of 28 m of diameter in the center of the existing system. At the threshold of 15 GeV, electromagnetic shower will be detected only by this big telescope so a new data analysis is needed. A new method based on a multidimensional analysis has been developed. Therefore, the energy of electromagnetic shower is well reconstructed with a good discrimination down to 30 GeV. At low energy, the sensitivity will be at a few percent of the Crab in 50 hours. This new method has been tested on H.E.S.S. data and is very competitive with respect to the other energy reconstruction methods; an extension for stereoscopic events is also shown. The calibration processes and the results of tests of photomultipliers are described. A propagation model of cosmic rays has been developed to study diffuse gamma ray emission. Protons and helium nuclei have been propagated in the galaxy to estimate the emission of neutral pion decays after an interaction with the interstellar medium. The map production is described from the beginning to the end. I have estimated the sensitivity of H.E.S.S. to the prediction of the model. The Sagittarius dwarf galaxy is studied as a dark matter dominated object. I used the most efficient analysis of the H.E.S.S collaboration and decomposed the data as a function of the zenith angle to decrease the energy threshold. (author)

  20. La biblioteca como editora de contenidos

    Directory of Open Access Journals (Sweden)

    Alonso-Arévalo, Julio

    2015-12-01

    Full Text Available Una de las características más innovadoras de la biblioteca del siglo 21 tiene que ver con la toma de una postura activa frente a la gestión y generación de contenidos. Con la llegada de la Web 2.0 las bibliotecas no sólo siguen salvaguardando y difundiendo información como han venido realizando a lo largo de su historia, también cada vez con más frecuencia crean nueva información con el objetivo de prestar los mejores servicios a sus ciudadanos, a través de recursos y servicios tales como la elaboración guías de investigación, boletines de alerta y novedades, recursos web, información a través de sus blogs, y como administradores de contenidos a través de repositorios y revistas de acceso abierto. Un paso más allá en esta dinámica tienen que ver con la biblioteca como editora y distribuidora de libros, especialmente en el ámbito local, siendo la impulsora, formadora, dinamizador y difusoras de las obras de los autores de su comunidad.

  1. La música como herramienta facilitadora del aprendizaje del inglés como lengua extranjera

    OpenAIRE

    Carmen María TOSCANO FUENTES; María Carmen FONSECA MORA

    2013-01-01

    Numerosas investigaciones aseguran que la inclusión de canciones y/o de elementos sonoro-musicales en la enseñanza de lenguas extranjeras (LE) aporta beneficios en el proceso de aprendizaje a niveles lingüísticos, afectivos y sociolingüísticos. El objetivo central de este estudio fue el de mostrar los resultados de un programa sonoro-musical puesto en práctica en la enseñanza de inglés como le con escolares españoles de sexto de primaria. Primeramente, se estudió cuantitativamente si el alumn...

  2. Fiber-Amplifier-Enhanced QEPAS Sensor for Simultaneous Trace Gas Detection of NH3 and H2S

    Directory of Open Access Journals (Sweden)

    Hongpeng Wu

    2015-10-01

    Full Text Available A selective and sensitive quartz enhanced photoacoustic spectroscopy (QEPAS sensor, employing an erbium-doped fiber amplifier (EDFA, and a distributed feedback (DFB laser operating at 1582 nm was demonstrated for simultaneous detection of ammonia (NH3 and hydrogen sulfide (H2S. Two interference-free absorption lines located at 6322.45 cm−1 and 6328.88 cm−1 for NH3 and H2S detection, respectively, were identified. The sensor was optimized in terms of current modulation depth for both of the two target gases. An electrical modulation cancellation unit was equipped to suppress the background noise caused by the stray light. An Allan-Werle variance analysis was performed to investigate the long-term performance of the fiber-amplifier-enhanced QEPAS sensor. Benefitting from the high power boosted by the EDFA, a detection sensitivity (1σ of 52 parts per billion by volume (ppbv and 17 ppbv for NH3 and H2S, respectively, were achieved with a 132 s data acquisition time at atmospheric pressure and room temperature.

  3. Fiber-Amplifier-Enhanced QEPAS Sensor for Simultaneous Trace Gas Detection of NH3 and H2S

    Science.gov (United States)

    Wu, Hongpeng; Dong, Lei; Liu, Xiaoli; Zheng, Huadan; Yin, Xukun; Ma, Weiguang; Zhang, Lei; Yin, Wangbao; Jia, Suotang

    2015-01-01

    A selective and sensitive quartz enhanced photoacoustic spectroscopy (QEPAS) sensor, employing an erbium-doped fiber amplifier (EDFA), and a distributed feedback (DFB) laser operating at 1582 nm was demonstrated for simultaneous detection of ammonia (NH3) and hydrogen sulfide (H2S). Two interference-free absorption lines located at 6322.45 cm−1 and 6328.88 cm−1 for NH3 and H2S detection, respectively, were identified. The sensor was optimized in terms of current modulation depth for both of the two target gases. An electrical modulation cancellation unit was equipped to suppress the background noise caused by the stray light. An Allan-Werle variance analysis was performed to investigate the long-term performance of the fiber-amplifier-enhanced QEPAS sensor. Benefitting from the high power boosted by the EDFA, a detection sensitivity (1σ) of 52 parts per billion by volume (ppbv) and 17 ppbv for NH3 and H2S, respectively, were achieved with a 132 s data acquisition time at atmospheric pressure and room temperature. PMID:26506351

  4. Studies on the relationship between Pitzer's equation and medium effect: the system of HCl + H{sub 2}SO{sub 4} in {l_brace}0.06455C{sub 2}H{sub 5}OH + 0.93545H{sub 2}O{r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Lu Xingmei E-mail: lxmqt@sohu.com; Xu Weiguo; Chang Xiaohong; Lu Dianzhen; Yang Jiazhen

    2004-03-01

    The second ionization constant of sulfuric acid in mixed solvent, K{sub 2}, was determined by e.m.f. of cell without liquid junction: (Pt,H{sub 2}(101.325 kPa) vertical bar HCl(m{sub 1}),H{sub 2}SO{sub 4}(m{sub 2}),{l_brace}ethanol(x=0.06455)+water(x=0.93545){r_brace} vertical bar AgCl-Ag))over the temperatures (278.15 to 318.15) K, where x is mole fraction. Combining Owen's definition of medium effect with Pitzer's equations, the values of combination parameters: ({lambda}{sub nHS}+{lambda}{sub nCl}-{lambda}{sub nS})+(3/2)m{sub n}({mu}{sub nnHS}+{mu}{sub nnC=} l-{mu}{sub nnS}),(1/2)({xi}{sub nHHS}+{xi}{sub nHCl}-{xi}{sub nHS}), that represent the interactions between ions and ethanol were obtained at 298.15 K.

  5. Disproportionation and thermochemical sulfate reduction reactions in S-H20-Ch4 and S-D2O-CH4 systems from 200 to 340 °C at elevated pressures

    Science.gov (United States)

    Yuan, Shunda; Chou, I-Ming; Burruss, Robert A.

    2013-01-01

    Elemental sulfur, as a transient intermediate compound, by-product, or catalyst, plays significant roles in thermochemical sulfate reduction (TSR) reactions. However, the mechanisms of the reactions in S-H2O-hydrocarbons systems are not clear. To improve our understanding of reaction mechanisms, we conducted a series of experiments between 200 and 340 °C for S-H2O-CH4, S-D2O-CH4, and S-CH4-1m ZnBr2 systems in fused silica capillary capsules (FSCC). After a heating period ranging from 24 to 2160 hours (hrs), the quenched samples were analyzed by Raman spectroscopy. Combined with the in situ Raman spectra collected at high temperatures and pressures in the S-H2O and S-H2O-CH4 systems, our results showed that (1) the disproportionation of sulfur in the S-H2O-CH4 system occurred at temperatures above 200 °C and produced H2S, SO42-, and possibly trace amount of HSO4-; (2) sulfate (and bisulfate), in the presence of sulfur, can be reduced by methane between 250 and 340 °C to produce CO2 and H2S, and these TSR temperatures are much closer to those of the natural system (2O-CH4 system may take place simultaneously, with TSR being favored at higher temperatures; and (4) in the system S-D2O-CH4, both TSR and the competitive disproportionation reactions occurred simultaneously at temperatures above 300 °C, but these reactions were very slow at lower temperatures. Our observation of methane reaction at 250 °C in a laboratory time scale suggests that, in a geologic time scale, methane may be destroyed by TSR reactions at temperatures > 200 °C that can be reached by deep drilling for hydrocarbon resources.

  6. Impact of elevated H2S on metabolite levels, activity of enzymes and expression of genes involved in cysteine metabolism

    NARCIS (Netherlands)

    Riemenschneider, A; Nikiforova, V.; Hoefgen, R; De Kok, LJ; Papenbrock, J

    The effects of elevated atmospheric hydrogen sulfide (H2S) levels (0.25, 0.5, and 0.75 mu l l(-1)) have been investigated in a short-term exposure experiment (3-48 h) on the model plant Arabidopsis thaliana (L.) Heynh. in comparison to untreated control plants. The most pronounced effects of H2S

  7. Analysis of the relationship between H{sub 2}S removal capacity and surface properties of unimpregnated activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Adib, F.; Bagreev, A.; Bandosz, T.J.

    2000-02-15

    The H{sub 2}S breakthrough capacity was measured on two series of activated carbons of a coconut shell and a bituminous coal origins. To broaden the spectrum of surface features the samples were oxidized using nitric acid or ammonium persulfate under conditions chosen to preserve their pore structures. Then the carbons were characterized using Boehm titration, potentiometric titration, thermal analysis, temperature programmed desorption, sorption of nitrogen, and sorption of water. It was found that the choice of unimpregnated carbon for application as H{sub 2}S adsorbent should be made based on parameters of its acidity such as number of acidic groups, pH of surface, amount of surface groups oxygen, or weight loss associated to decomposition of surface oxygen species. The results obtained from the analyses of six unimpregnated carbon samples suggest that there are certain threshold values of these quantities which, when exceeded, have a dramatic effect on the H{sub 2}S breakthrough capacity.

  8. Cu2ZnSnS4 solar cells fabricated by short-term sulfurization of sputtered Sn/Zn/Cu precursors under an H2S atmosphere

    International Nuclear Information System (INIS)

    Emrani, Amin; Rajbhandari, Pravakar P.; Dhakal, Tara P.; Westgate, Charles R.

    2015-01-01

    Synthesis of Cu 2 ZnSnS 4 (CZTS) thin films by short-term sulfurization of sputtered Sn/Zn/Cu precursors under ambient H 2 S is studied. The effect of the sulfurization processes on the film morphology, surface roughness, composition of the CZTS, and the crystallinity was investigated by using scanning electron microscopy, optical profiler, energy dispersive spectroscopy, and X-ray diffraction respectively. To further explore the CZTS layer, the following additional layers were deposited to complete the solar cells: CdS with chemical bath deposition; ZnO and Al 2 O 3 -doped ZnO with RF magnetron deposition; and, silver fingers as the front contact as the last layer. The optical and morphological properties of the CZTS films were investigated and compared. Subsequently, the electrical characteristics and the efficiencies of the regarding solar cells were analyzed. A maximum efficiency of 3.8% has been obtained for the fast sulfurization (30 min at 580 °C) and finally, the performance is compared with our best cell fabricated through the more common slow annealing. - Highlights: • Development of Cu 2 ZnSnS 4 (CZTS) solar cells using elemental metal sputtering • 112-oriented CZTS films with well-defined morphology obtained • Reported efficiency of 3.8% for a short-term annealing (less than 30 min) under ambient H 2 S • A detailed comparison between the fast and the more common slow annealing is reported

  9. Control and monitoring of H2S in environments of Heavy Water Plant (Kota) (Paper No. 4.5)

    International Nuclear Information System (INIS)

    Hiremath, S.C.; Unni, V.K.R.

    1992-01-01

    Heavy Water Plant (Kota) utilizes dual temperature exchange process of hydrogen sulphide and water for extracting deuterium from water upto 15% and vacuum distillation process for enriching it from 15 to 99.8%. H 2 S gas is used in large quantities as a carrier gas to extract the deuterium content of water. The safe handling of large quantities of H 2 S gas poses a major problem. The properties of H 2 S gas are : high toxicity, high corrosive nature, high flammability and explosiveness. To overcome these properties all safety aspects have been considered while designing, fabricating, constructing and operating the plant and a number of design safety features have been incorporated in the systems. Some of the typical unusual occurrences happened have also been described. (author)

  10. H2S interaction with Cu(100)-(22 × √2 )R45°-O: Formation of a metastable ‖05 52sulfur surface reconstruction

    DEFF Research Database (Denmark)

    Colaianni, M. L.; Syhler, P.; Chorkendorff, Ib

    1995-01-01

    This paper utilizes scanning tunneling microscopy, low-energy electron diffraction, Auger-electron spectroscopy, and temperature-programmed desorption to examine a metastable \\(52)(05)\\-S structure which forms after the interface reaction of H2S with a Cu(100)-(2 root (2) over bar X root (2) over....... Heating the \\(52)(05)\\-S surface to temperatures above 600 K converts this structure to the thermally stable Cu(100)rootX root)R14 degrees-S (i.e., \\((1) over bar 4)(41)\\-S overlayer. A model for the metastable \\(52)(05)\\-S reconstruction is proposed....

  11. Hydrogen Diffusion and H{sub 2}S Corrosion in Steel

    Energy Technology Data Exchange (ETDEWEB)

    Haugstveit, Bjarte Erlend

    2001-01-01

    The electrochemical permeation technique introduced by Devanathan and Stachurski has been used to measure the effective diffusivity of hydrogen in steel in a H{sub 2}S-saturated aqueous environment. The linear polarization resistance (LPR) method has been used to measure the corrosion rate. The effective diffusion coefficient of hydrogen has been found to be in the range of 1*10-12 to 7*10-11, depending on the environmental conditions. The corrosion film was identified as mackinawite, and it affected the permeation process of hydrogen. The results supported the assumption that the diffusion process can be described by a three layer model and indicated that the model could be reduced to a two layer model in the cases of iron and steel. A model aimed to describe the reaction pathway of hydrogen through the surface film and into the steel is proposed. The corrosion film influenced the corrosion rate, and it was least protective against corrosion at pH 6.5. Corrosion rates were in the range of 0.2-1 mm/year. The corrosion rate was increased significantly at pH 3.5, but the effect of the surface film was stronger and overshadowed the pH effect at the higher pH values. Increased flow velocity also lead to increased corrosion rate, but this effect was less significant compared to the effect of pH and the surface film. DEG decreased the corrosion rate. The uncertainty in the diffusion measurements was mainly due to the assumption of a constant sub-surface concentration of atomic hydrogen, which was not fulfilled. A method less dependent on constant surface conditions would probably yield better estimates of the effective diffusivity. The uncertainty in the corrosion measurements was mainly due to the uncertainty in the value of the Stern-Geary constant. The qualitative assumptions based on the results in this thesis are assumed to be valid. A test section designed for this thesis was tested and was found successful in corrosion rate measurements, but proved to be

  12. Syngas production by gasification of aquatic biomass with CO2/O2 and simultaneous removal of H2S and COS using char obtained in the gasification

    International Nuclear Information System (INIS)

    Hanaoka, Toshiaki; Hiasa, Shou; Edashige, Yusuke

    2013-01-01

    Applicability of gulfweed as feedstock for a biomass-to-liquid (BTL) process was studied for both production of gas with high syngas (CO + H 2 ) content via gasification of gulfweed and removal of gaseous impurities using char obtained in the gasification. Gulfweed as aqueous biomass was gasified with He/CO 2 /O 2 using a downdraft fixed-bed gasifier at ambient pressure and 900 °C at equivalence ratios (ER) of 0.1–0.3. The syngas content increased while the conversion to gas on a carbon basis decreased with decreasing ER. At an ER of 0.1 and He/CO 2 /O 2 = 0/85/15%, the syngas content was maximized at 67.6% and conversion to gas on a carbon basis was 94.2%. The behavior of the desulfurization using char obtained during the gasification process at ER = 0.1 and He/CO 2 /O 2 = 0/85/15% was investigated using a downdraft fixed-bed reactor at 250–550 °C under 3 atmospheres (H 2 S/N 2 , COS/N 2 , and a mixture of gases composed of CO, CO 2 , H 2 , N 2 , CH 4 , H 2 S, COS, and steam). The char had a higher COS removal capacity at 350 °C than commercial activated carbon because (Ca,Mg)S crystals were formed during desulfurization. The char simultaneously removed H 2 S and COS from the mixture of gases at 450 °C more efficiently than did activated carbon. These results support this novel BTL process consisting of gasification of gulfweed with CO 2 /O 2 and dry gas cleaning using self-supplied bed material. -- Highlights: • A product gas with high syngas content was produced from the gasification of gulfweed with CO 2 /O 2 . • The syngas content increased with decreasing the equivalence ratio. • The syngas content was maximized at 67.6% at an ER of 0.1 and He/CO 2 /O 2 = 0/85/15%. • The char simultaneously removed H 2 S and COS from a mixture of gases at 450 °C efficiently

  13. Single-molecule magnets: structure and properties of [Mn18O14(O2CMe)18(hep)4(hepH)2(H2O)2](ClO4)2 with spin S = 13.

    Science.gov (United States)

    Brechin, E K; Sañudo, E C; Wernsdorfer, W; Boskovic, C; Yoo, J; Hendrickson, D N; Yamaguchi, A; Ishimoto, H; Concolino, T E; Rheingold, A L; Christou, G

    2005-02-07

    The reaction of 2-(hydroxyethyl)pyridine (hepH) with a 2:1 molar mixture of [Mn3O(O2CMe)6(py)3]ClO4 and [Mn3O(O2CMe)6(py)3] in MeCN afforded the new mixed-valent (16Mn(III), 2Mn(II)), octadecanuclear complex [Mn18O14(O2CMe)18(hep)4(hepH)2(H2O)2](ClO4)2 (1) in 20% yield. Complex 1 crystallizes in the triclinic space group P. Direct current magnetic susceptibility studies in a 1.0 T field in the 5.0-300 K range, and variable-temperature variable-field dc magnetization studies in the 2.0-4.0 K and 2.0-5.0 T ranges were obtained on polycrystalline samples. Fitting of magnetization data established that complex 1 possesses a ground-state spin of S = 13 and D = -0.18 K. This was confirmed by the value of the in-phase ac magnetic susceptibility signal. Below 3 K, the complex exhibits a frequency-dependent drop in the in-phase signal, and a concomitant increase in the out-of-phase signal, consistent with slow magnetization relaxation on the ac time scale. This suggests the complex is a single-molecule magnet (SMM), and this was confirmed by hysteresis loops below 1 K in magnetization versus dc field sweeps on a single crystal. Alternating current and direct current magnetization data were combined to yield an Arrhenius plot from which was obtained the effective barrier (U(eff)) for magnetization reversal of 21.3 K. Below 0.2 K, the relaxation becomes temperature-independent, consistent with relaxation only by quantum tunneling of the magnetization (QTM) through the anisotropy barrier via the lowest-energy MS = +/-13 levels of the S = 13 spin manifold. Complex 1 is thus the SMM with the largest ground-state spin to display QTM.

  14. Nano Ag-Doped In2O3 Thick Film: A Low-Temperature H2S Gas Sensor

    Directory of Open Access Journals (Sweden)

    D. N. Chavan

    2011-01-01

    Full Text Available Thick films of AR grade In2O3 were prepared by standard screen-printing technique. The gas sensing performances of thick films were tested for various gases. It showed maximum sensitivity to ethanol vapour at 350°C for 80 ppm concentration. To improve the sensitivity and selectivity of the film towards a particular gas, In2O3 sensors were surface-modified by dipping them in a solution of 2% nanosilver for different intervals of time. Obtained results indicated that spherical nano-Ag grains are highly dispersed on the surface of In2O3sensor. The surface area of the nano-Ag/ In2O3 sensor is several times larger than that of pure In2O3 sensor. In comparison with pure In2O3 sensor, all of the nano-Ag-doped sensors showed better sensing performance in respect of response, selectivity, and optimum operating temperature. The surface-modified (30 min In2O3 sensor showed larger sensitivity to H2S gas (10 ppm at 100°C. Nano silver on the surface of the film shifts the reactivity of film from ethanol vapour to H2S gas. A systematic study of gas sensing performance of the sensor indicates the key role played by the nano silver species on the surface. The sensitivity, selectivity, response, and recovery time of the sensor were measured and presented.

  15. 5-Isobutyl-4-phenylsulfonyl-1H-pyrazol-3(2H-one

    Directory of Open Access Journals (Sweden)

    M. Venkatesh

    2010-12-01

    Full Text Available The title compound, C13H16N2O3S, consists of two crystallographically independent molecules with similar geometries and exists in a keto form, the C=O bond lengths being 1.267 (2 and 1.254 (2 Å. In both molecules, the pyrazole rings are approximately planar, with maximum deviations of 0.017 (2 and 0.010 (2 Å, and the dihedral angles between the pyrazole and phenyl rings are 83.63 (11 and 70.07 (12°. In one molecule, an intramolecular C—H...O hydrogen bond with an S(6 ring motif is observed. In the crystal, intermolecular N—H...O and C—H...O hydrogen bonds link the molecules into two-dimensional networks parallel to the ab plane.

  16. Comparative pathology of pigs infected with Korean H1N1, H1N2, or H3N2 swine influenza A viruses

    OpenAIRE

    Lyoo, Kwang-Soo; Kim, Jeong-Ki; Jung, Kwonil; Kang, Bo-Kyu; Song, Daesub

    2014-01-01

    Background The predominant subtypes of swine influenza A virus (SIV) in Korea swine population are H1N1, H1N2, and H3N2. The viruses are genetically close to the classical U.S. H1N1 and triple-reassortant H1N2 and H3N2 viruses, respectively. Comparative pathogenesis caused by Korean H1N1, H1N2, and H3N2 SIV was evaluated in this study. Findings The H3N2 infected pigs had severe scores of gross and histopathological lesions at post-inoculation days (PID) 2, and this then progressively decrease...

  17. The effects of the massless O(αs2), O(ααs), O(α2) QCD and QED corrections and of the massive contributions to Γ(H0→bb-bar)

    International Nuclear Information System (INIS)

    Kataev, A.L.

    1992-11-01

    The expression for the decay width of H 0 →bb-bar process in terms of the b-quark pole mass is presented, with the order O(α s 2 ), O(αα s ) and O(α 2 ) massless corrections and of the order O(m b 2 /M H 2 ) QCD contributions taken into account. The results demonstrate that in the region 50 GeV H2M W the higher order QCD effects reduce the Born expression for Γ Hb( b-bar) by over 50%. The theoretical uncertainties of the QCD predictions for Γ Hb( b-bar) are analyzed in detail. The importance of taking into account of the order O(m b 2 /M H 2 )-corrections for modelling the threshold effects is stressed. (author) 33 refs.; 7 figs

  18. COBALTO COMO RETARDANTE DE LA SENESCENCIA DE Lilium HÍBRIDO ORIENTAL EN POSTCOSECHA

    Directory of Open Access Journals (Sweden)

    Manuel Mandujano-Piña

    2012-01-01

    Full Text Available La calidad en las flores cortadas se ve afectada debido a los largos periodos de exposición a temperaturas cálidas, estrés hídrico y daños mecánicos. Diversas investigaciones han identificado una serie de aspectos técnicos para prolongar la vida de las flores cortadas, entre los que resaltan el uso de soluciones preservadoras que además puedan inhibir la síntesis de etileno. En la presente investigación se evaluaron los efectos del cloruro de cobalto (Co sobre el peso, consumo de solución, unidades SPAD en hojas, contenido de nitrógeno, cobalto, potasio, calcio, magnesio y hierro, así como vida postcosecha, en tallos de Lilium híbrido oriental 'Star Gazer' y 'Star Fighter'. Los tallos florales fueron obtenidos en Villa Guerrero, Estado de México, y transportados en seco al laboratorio, donde se estableció un experimento factorial 2 x 5 en un diseño experimental completamente al azar. Se utilizaron soluciones que contenían como fuente de carbono sacarosa al 4 % y las siguientes concentraciones de Co: 0.0, 0.1, 0.2, 0.4 y 0.8 mM. Lo anterior permitió establecer que Co 0.1 y 0.2 mM retrasaron los síntomas de senescencia de los tallos florales de Lilium.

  19. Corrosive effect of oil's accompanying water polluted with H2S over steel (API 5L X-52)

    International Nuclear Information System (INIS)

    Cueli Corugedo, Alexander; Adames Montero, Yosmari; Rivera Beltran, Yischy; Davis Harriet, Juan

    2013-01-01

    The corrosion from the steel to the carbon in the sale oil pipage conduction, is a serious problem, due to the material and economical looses they cause, damaging even in some cases the productive field. The purpose of this study is to determine the aggressiveness of the oil's water layer, polluted with H 2 S ( g) , over the steel of pipelines' construction (API 5L X-52), taking into account the temperature variations which take place during the transportation of the oil, using the electrochemical techniques of polarisation resistance (LPR) and electrochemical noise. It is pretended to determine the velocity of steel corrosion in the oil's water layer polluted with H 2 S through electrochemical techniques. It was shown that the temperature increases and the concentration of H 2 S to 500 ppm in the oil's accompanying water emphasizes the corrosion phenomenon experienced by the steel (9, 188 0 mm/year to 70℃).The results of the electrochemical noise spectrums and the values of the localisation ?s index calculated, shown the presence of corrosion on the steel surface (API 5L X-52).This result was complemented through optic Microscopy which permits to corroborate the poor adherence of the sulphur layers deposited on the metal that increase the appearance of events found with the temperature increase and the concentration of H 2 S in the environment studied

  20. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

    Science.gov (United States)

    Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

    2013-01-01

    We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

  1. H2S Attenuates LPS-Induced Acute Lung Injury by Reducing Oxidative/Nitrative Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Hong-Xia Zhang

    2016-12-01

    Full Text Available Background: Hydrogen sulfide (H2S, known as the third endogenous gaseous transmitter, has received increasing attention because of its diverse effects, including angiogenesis, vascular relaxation and myocardial protection.We aimed to investigate the role of H2S in oxidative/nitrative stress and inflammation in acute lung injury (ALI induced by endotoxemia. Methods: Male ICR mice were divided in six groups: (1 Control group; (2 GYY4137treatment group; (3 L-NAME treatment group; (4 lipopolysaccharide (LPS treatment group; (5 LPS with GYY4137 treatment group; and (6 LPS with L-NAME treatment group. The lungs were analysed by histology, NO production in the mouse lungs determined by modified Griess (Sigma-Aldrich reaction, cytokine levels utilizing commercialkits, and protein abundance by Western blotting. Results: GYY4137, a slowly-releasing H2S donor, improved the histopathological changes in the lungs of endotoxemic mice. Treatment with NG-nitro-L-arginine methyl ester (L-NAME, a nitric oxide synthase (NOS inhibitor, increased anti-oxidant biomarkers such as thetotal antioxidant capacity (T-AOC and theactivities of catalase (CAT and superoxide dismutase (SOD but decreased a marker of peroxynitrite (ONOO- action and 3-nitrotyrosine (3-NT in endotoxemic lung. L-NAME administration also suppressed inflammation in endotoxemic lung, as evidenced by the decreased pulmonary levels of interleukin (IL-6, IL-8, and myeloperoxidase (MPO and the increased level of anti-inflammatory cytokine IL-10. GYY4137 treatment reversed endotoxin-induced oxidative/nitrative stress, as evidenced by a decrease in malondialdehyde (MDA, hydrogenperoxide (H2O2 and 3-NT and an increase in the antioxidant biomarker ratio of reduced/oxidized glutathione(GSH/GSSG ratio and T-AOC, CAT and SOD activity. GYY4137 also attenuated endotoxin-induced lung inflammation. Moreover, treatment with GYY4137 inhibited inducible NOS (iNOS expression and nitric oxide (NO production in the

  2. A facile solvent-free Synthesis Route for the Assembly of Highly CO2 Selective and H2S tolerant NiSIFSIX Metal-Organic Framework

    KAUST Repository

    Eddaoudi, Mohamed; Shekhah, Osama; Belmabkhout, Youssef; Adil, Karim; Cairns, Amy J.; Bhatt, Prashant

    2015-01-01

    The development of materials for CO2 capture with high selectivity and high tolerance to H2S is of prime importance for various industrially relevant gas streams (e.g. natural gas and biogas upgrading as well as pre-combustion capture). Here, we report the successful fabrication of a MOF with combined exceptional CO2 capture properties and H2S tolerance, namely Ni SIFSIX based-MOF using both solvothermal and solvent-free methodologies.

  3. A facile solvent-free Synthesis Route for the Assembly of Highly CO2 Selective and H2S tolerant NiSIFSIX Metal-Organic Framework

    KAUST Repository

    Eddaoudi, Mohamed

    2015-07-06

    The development of materials for CO2 capture with high selectivity and high tolerance to H2S is of prime importance for various industrially relevant gas streams (e.g. natural gas and biogas upgrading as well as pre-combustion capture). Here, we report the successful fabrication of a MOF with combined exceptional CO2 capture properties and H2S tolerance, namely Ni SIFSIX based-MOF using both solvothermal and solvent-free methodologies.

  4. Biofiltration of wastewater lift station emissions: evaluation of VOC removal in the presence of H{sub 2}S

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Alvaro; Rathibandla, Snehasheela; Jones, Kim; Cabezas, Jose [Texas A and M University-Kingsville, Department of Environmental Engineering, Kingsville, TX (United States)

    2008-02-15

    The capacity of biofilter systems to remove volatile organic compounds in the presence of high concentrations of hydrogen sulfide was investigated for applications in wastewater lift stations. The treatment system was an enclosed unit composed of a biotrickling filter coupled with a biofilter. The biofilter media were plastic hollow spherical balls filled with a compost mixture; and the biotrickling filter media was a structured plastic packing. The gases from the pumping station wet well were a mixture of H{sub 2}S and low concentration aliphatic and aromatic VOCs, toluene being the most significant in concentrations of 41 ppb. The H{sub 2}S concentration was 314 ppm with fluctuations of 100 ppm resulting from pumping cycles at the station. No inhibition effect was detected from the simultaneous biological removal of VOCs and H{sub 2}S: toluene removal efficiency was 91% with the two sections contributing approximately equally to the pollutant removal; and the average removal of H{sub 2}S was 74%. A traditional open-in-ground biofilter filled with wood chips and compost, existing in the site, attained similar removal efficiencies for toluene, but the elimination capacity of the biotrickling/biofilter system was 3.3-times higher than the open biofilter. (orig.)

  5. Preparation of {sup 35}SO{sub 4}H{sub 2} and of some other {sup 35}S labeled mineral compounds; Preparation de {sup 35}SO{sub 4}H{sub 2} et de quelques autres composes mineraux simples marques a {sup 35}S

    Energy Technology Data Exchange (ETDEWEB)

    De la Gueronniere, E; Henry, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Methods of preparation, from pile irradiated KCI, of the following labeled molecules are described: - carrier free H{sub 2}SO{sub 4} - SCd (100 m curies/milli mole) - solution of SNa{sub 2} (100 m curies/milli mole) - solution of SK{sub 2} (100 m curies/milli mole) - S metalloid (100 m curies/milli mole) - SO{sub 3}Na{sub 2} (90 m curies/milli mole) - S{sub 2}C{sub 3}Na{sub 2} (50 m curies/mammalia). (author) [French] On decrit les methodes de preparation, a partir de KCl irradie dans les piles, des molecules suivantes marquees au {sup 35}S: - SO{sub 4}H{sub 2} (sans entraineur) - SCd (100 mcuries/millimole) - solution de SNa{sub 2} (100 mcuries/millimole) - solution de SK{sub 2} (100 mcuries/millimole) - S metalloide (100 mcuries/millimole) - Na{sub 2}SO{sub 3} (90 mcuries/millimole) - Na{sub 2}S{sub 2}C{sub 3} (50 mcuries/milIimole). (auteur)

  6. 2-(1H-Benzimidazol-2-ylphenol

    Directory of Open Access Journals (Sweden)

    S. M. Prakash

    2014-02-01

    Full Text Available The title molecule, C13H10N2O, is essentially planar, the maximum deviation from the plane of the non-H atoms being 0.016 (2 Å. The imidazole ring makes a dihedral angle of 0.37 (13° with the attached benzene ring. An intramolecular O—H...N hydrogen bond generates an S(6 ring motif. In the crystal, molecules are linked through N—H...O hydrogen bonds, forming chains propagating in [001]. The crystal packing also features four π–π stacking interactions involving the imidazole ring, fused benzene ring and attached benzene ring system [centroid–centroid distances = 3.6106 (17, 3.6108 (17, 3.6666 (17 and 3.6668 (17 Å].

  7. A thermodynamic model for C-(N-)A-S-H gel: CNASH{sub s}s. Derivation and validation

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Rupert J.; Bernal, Susan A.; Provis, John L., E-mail: j.provis@sheffield.ac.uk

    2014-12-15

    The main reaction product in Ca-rich alkali-activated cements and hybrid Portland cement (PC)-based materials is a calcium (alkali) aluminosilicate hydrate (C-(N-)A-S-H) gel. Thermodynamic models without explicit definitions of structurally-incorporated Al species have been used in numerous past studies to describe this gel, but offer limited ability to simulate the chemistry of blended PC materials and alkali-activated cements. Here, a thermodynamic model for C-(N-)A-S-H gel is derived and parameterised to describe solubility data for the CaO–(Na{sub 2}O,Al{sub 2}O{sub 3})–SiO{sub 2}–H{sub 2}O systems and alkali-activated slag (AAS) cements, and chemical composition data for C-A-S-H gels. Simulated C-(N-)A-S-H gel densities and molar volumes are consistent with the corresponding values reported for AAS cements, meaning that the model can be used to describe chemical shrinkage in these materials. Therefore, this model can provide insight into the chemistry of AAS cements at advanced ages, which is important for understanding the long-term durability of these materials.

  8. Role of the Material Electrodes on Resistive Behaviour of Carbon Nanotube-Based Gas Sensors for H2S Detection

    Directory of Open Access Journals (Sweden)

    M. Lucci

    2012-01-01

    Full Text Available Miniaturized gas-sensing devices that use single-walled carbon nanotubes as active material have been fabricated using two different electrode materials, namely, Au/Cr and NbN. The resistive sensors have been assembled aligning by dielectrophoresis the nanotube bundles between 40 μm spaced Au/Cr or NbN multifinger electrodes. The sensing devices have been tested for detection of the H2S gas, in the concentration range 10–100 ppm, using N2 as carrier gas. No resistance changes were detected using sensor fabricated with NbN electrodes, whereas the response of the sensor fabricated with Au/Cr electrodes was characterized by an increase of the resistance upon gas exposure. The main performances of this sensor are a detection limit for H2S of 10 ppm and a recovery time of few minutes. The present study suggests that the mechanism involved in H2S gas detection is not a direct charge transfer between molecules and nanotubes. The hypothesis is that detection occurs through passivation of the Au surfaces by H2S molecules and modification of the contact resistance at the Au/nanotube interface.

  9. SnO2 COMO CATALIZADOR Y SOPORTE DE Ni Y Sn EN LA ALCOHOLISIS DEL ACEITE DE PALMA

    Directory of Open Access Journals (Sweden)

    CARLOS E. ARARAT

    2011-01-01

    Full Text Available El óxido de estaño en forma de SnO2 (casiterita ha sido usado como catalizador en diferentes procesos de interés de la industria química, tales como la de deshidrogenación, cracking, isomerización y oxidación de hidrocarburos. En este trabajo se estudió la aplicación de SnO2 como catalizador y como soporte de especies de níquel y estaño, en la alcohólisis del aceite de palma. La obtención del SnO2 se realizó por el método de precipitación y la incorporación de níquel y estaño, al soporte, por el método de impregnación. Se determinó que el SnO2 presentaba una mayor actividad frente a la reacción de alcohólisis en comparación con otros óxidos, tal como el MgO, y que esta actividad era afectada por la adición de níquel y estaño en su superficie. Se utilizó cromatografía de gases CG para el seguimiento de las reacciones, así como la espectroscopia FTIR para realizar el análisis de los productos obtenidos después del proceso. Los catalizadores fueron analizados por DRX para la determinación de las fases cristalinas presentes y del análisis de área superficial, volumen y tamaño de poro, para determinar las propiedades texturales de los catalizadores.

  10. Seroprevalence of H1N1, H3N2 and H1N2 influenza viruses in pigs in seven European countries in 2002-2003

    NARCIS (Netherlands)

    Reeth, K.; Brown, I.H.; Durrwald, R.; Foni, E.; Labarque, G.; Lenihan, P.; Maldonado, J.; Markowska-Daniel, I.; Pensaert, M.; Pospisil, Z.; Koch, G.

    2008-01-01

    Objectives Avian-like H1N1 and human-like H3N2 swine influenza viruses (SIV) have been considered widespread among pigs in Western Europe since the 1980s, and a novel H1N2 reassortant with a human-like H1 emerged in the mid 1990s. This study, which was part of the EC-funded 'European Surveillance

  11. Interface sulfur passivation using H2S annealing for atomic-layer-deposited Al2O3 films on an ultrathin-body In0.53Ga0.47As-on-insulator

    International Nuclear Information System (INIS)

    Jin, Hyun Soo; Cho, Young Jin; Lee, Sang-Moon; Kim, Dae Hyun; Kim, Dae Woong; Lee, Dongsoo; Park, Jong-Bong; Won, Jeong Yeon; Lee, Myoung-Jae; Cho, Seong-Ho; Hwang, Cheol Seong; Park, Tae Joo

    2014-01-01

    Highlights: • ALD Al 2 O 3 films were grown on ultrathin-body In 0.53 Ga 0.47 As substrates for III-V compound-semiconductor-based devices. • Interface sulfur passivation was performed with wet processing using (NH 4 ) 2 S solution, and dry processing using post-deposition annealing under a H 2 S atmosphere. • Electrical properties of the device were better for (NH 4 ) 2 S wet-treatment than the PDA under a H 2 S atmosphere. • PDA under a H 2 S atmosphere following (NH 4 ) 2 S wet-treatment resulted in an increased S concentration at the interface, which improved the electrical properties of the devices. - Abstract: Atomic-layer-deposited Al 2 O 3 films were grown on ultrathin-body In 0.53 Ga 0.47 As substrates for III-V compound-semiconductor-based devices. Interface sulfur (S) passivation was performed with wet processing using ammonium sulfide ((NH 4 ) 2 S) solution, and dry processing using post-deposition annealing (PDA) under a H 2 S atmosphere. The PDA under the H 2 S atmosphere resulted in a lower S concentration at the interface and a thicker interfacial layer than the case with (NH 4 ) 2 S wet-treatment. The electrical properties of the device, including the interface property estimated through frequency dispersion in capacitance, were better for (NH 4 ) 2 S wet-treatment than the PDA under a H 2 S atmosphere. They might be improved, however, by optimizing the process conditions of PDA. The PDA under a H 2 S atmosphere following (NH 4 ) 2 S wet-treatment resulted in an increased S concentration at the interface, which improved the electrical properties of the devices

  12. l-cysteine desulfhydrase-related H2 S production is involved in OsSE5-promoted ammonium tolerance in roots of Oryza sativa.

    Science.gov (United States)

    Guo, Hongming; Zhou, Heng; Zhang, Jing; Guan, Wenxue; Xu, Sheng; Shen, Wenbiao; Xu, Guohua; Xie, Yanjie; Foyer, Christine Helen

    2017-09-01

    Previous studies revealed that rice heme oxygenase PHOTOPERIOD SENSITIVITY 5 (OsSE5) is involved in the regulation of tolerance to excess ammonium by enhancing antioxidant defence. In this study, the relationship between OsSE5 and hydrogen sulfide (H 2 S), a well-known signalling molecule, was investigated. Results showed that NH 4 Cl triggered the induction of l-cysteine desulfhydrase (l-DES)-related H 2 S production in rice seedling roots. A H 2 S donor not only alleviated the excess ammonium-triggered inhibition of root growth but also reduced endogenous ammonium, both of which were aggravated by hypotaurine (HT, a H 2 S scavenger) or dl-propargylglycine (PAG, a l-DES inhibitor). Nitrogen metabolism-related enzymes were activated by H 2 S, thus resulting in the induction of amino acid synthesis and total nitrogen content. Interestingly, the activity of l-DES, as well as the enzymes involved in nitrogen metabolism, was significantly increased in the OsSE5-overexpression line (35S:OsSE5), whereas it impaired in the OsSE5-knockdown mutant (OsSE5-RNAi). The application of the HT/PAG or H 2 S donor could differentially block or rescue NH 4 Cl-hyposensitivity or hypersensitivity phenotypes in 35S:OsSE5-1 or OsSE5-RNAi-1 plants, with a concomitant modulation of nitrogen assimilation. Taken together, these results illustrated that H 2 S function as an indispensable positive regulator participated in OsSE5-promoted ammonium tolerance, in which nitrogen metabolism was facilitated. © 2017 John Wiley & Sons Ltd.

  13. Modeling Water Saturation Points in Natural Gas Streams Containing CO2 and H2S-Comparisons with Different Equations of State

    DEFF Research Database (Denmark)

    dos Santos, Leticia C.; Abunahman, Samir S.; Tavares, Frederico W.

    2015-01-01

    Since the discovery of the Pre-Salt layer in Brazilian waters, production of high gas-oil ratio (GOR) has increased considerably. This gas has a high content of water, CO2, and sometimes H2S. A study in different conditions was conducted using several equations of state (EoS) such as Peng...

  14. Effects of hydrogen sulfide (H2S) on respiration control of state 3/4 in ...

    African Journals Online (AJOL)

    hope&shola

    2012-03-13

    Mar 13, 2012 ... blood flow. In patients with ... electrode was inserted into the reaction vessel, and 0.2 M succinic sodium 20 μL ... stable H2S donor, was at 10. −5 to 10. −4 ..... human colonic epithelial cells to the adverse effects of the luminal.

  15. Study of the solubility, viscosity and density in Na+, Zn2+/Cl− − H2O, Na+ − Zn2+ − (H2PO2)− − H2O, Na+, Cl−/(H2PO2)− − H2O, and Zn2+, Cl−/(H2PO2)− − H2O ternary systems, and in Na+, Zn2+/Cl−, (H2PO2)−//H2O reciprocal quaternary system at 273.15 K

    International Nuclear Information System (INIS)

    Adiguzel, Vedat; Erge, Hasan; Alisoglu, Vahit; Necefoglu, Hacali

    2014-01-01

    Highlights: • The physicochemical properties of ternary and one quaternary have been studied. • Reciprocal quaternary systems’ solubility and phase equilibrium have been studied. • In all systems the solid phases have been found. • It was found that Zn(H 2 PO 2 ) 2 salt contains 70% of the general crystallization field. - Abstract: The solubility and the physicochemical properties (density, viscosity) in the Na-Zn- Cl-H 2 O), (Na + Zn + H 2 PO 2 + H 2 O), (Na + Cl + H 2 PO 2 + H 2 O), and (Zn + Cl + H 2 PO 2 + H 2 O) ternaries, and in Na + , Zn 2+ /Cl − , (H 2 PO 2 ) − //H 2 O reciprocal quaternary systems at T = 273.15 K were investigated by using the isothermal method. The diagrams of ternary salts systems, (NaCl + ZnCl 2 + H 2 O), (NaCl + NaH 2 PO 2 + H 2 O), (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), are plotted in figures 1–4. However, whole ions of reciprocal quaternary salt systems are plotted in figure 5. Additionally, the density and viscosity values of ternary systems vs. their corresponding composition values in weight per cent are plotted in figures 6–10. At the (i) (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ii) (NaCl + ZnCl 2 + H 2 O), (iii) (NaCl + NaH 2 PO 2 + H 2 O), (iv) (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O) ternary systems the solid phase compositions have been determined as: (i) Zn(H 2 PO 2 ) 2H 2 O, Zn(H 2 PO 2 ) 2 , ZnCl 22H 2 O, (ii) NaCl, 2NaCl ⋅ ZnCl 22H 2 O, and ZnCl 22H 2 O, (iii) NaCl and NaH 2 PO 2H 2 O, (iv) Zn(H 2 PO 2 ) 2H 2 O and NaH 2 PO 2H 2 O, respectively. On the other hand reciprocal quaternary system was observed as: ZnCl 22H 2 O, 2NaCl ⋅ ZnCl 22H 2 O, Zn(H 2 PO 2 ) 2H 2 O, NaH 2 PO 2H 2 O, NaCl. According to results, the least soluble salt was Zn(H 2 PO 2 ) 2 . The crystallization field of this salt, being the largest in comparison with those of other salts, occupied 70% of the general crystallization field

  16. Mathematical modeling of the hydrogen evolution reaction using HClO{sub 4} and H{sub 2}SO{sub 4} as electrolytes; Modelacion matematica de la reaccion de evolucion del hidrogeno utilizando HClO{sub 4} y H{sub 2}SO{sub 4} como electrolitos

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Chavez, Laura; Herrera Peraza, Eduardo; Alonso Nunez, Gabriel [Centro de Investigacion en Materiales Avanzados, Chihuahua, Chihuahua (Mexico); Manzanarez Papayanopoulos, Luisa [PROFEPA, Mexico D.F. (Mexico); Verde Gomez, Ysmael [Instituto Tecnologico de Cancun, Cancun, Quintana Roo (Mexico); Keer Rendon, Arturo [Centro de Investigacion en Materiales Avanzados, Chihuahua, Chihuahua (Mexico)

    2008-01-15

    tecnologia, se ha visto limitada por factores tales como el elevado costo de los distintos componentes que conforman una celda de combustible. Por ejemplo, el platino empleado por excelencia como el mejor catalizador para llevar a cabo la reaccion quimica entre hidrogeno y oxigeno, responsable de la produccion de energia electrica. En la busqueda de la optimizacion o sustitucion del platino, es importante contar con una metodologia que permita realizar un diagnostico in situ del estado de dicho catalizador. Este diagnostico involucra aspectos tales como la determinacion de los sitios activos y la carga y la degradacion que el catalizador puede ir sufriendo durante el funcionamiento de la celda. El presente trabajo consiste en el desarrollo de un modelo matematico que alimentado con las constantes de velocidad y los fenomenos involucrados en la reaccion de la evolucion del hidrogeno, produce como datos de salida, las curvas de polarizacion (E vs I) y de espectroscopia de impedancia electroquimica para dicha reaccion. Se considero para la modelacion, al Pt monocristalino preferenciado en las direcciones (111) y (100) como catalizador y usando diversos acidos como electrolitos. Las curvas obtenidas con el algoritmo matematico muestran una correlacion de la influencia del tipo y concentracion de los acidos usados como electrolitos y la densidad de corriente electrica debido a la evolucion del H{sub 2}. Finalmente, este modelo deja abierta la posibilidad de explorar el efecto del cambio en los valores de las variables involucradas en las reacciones de una celda de combustible, lo que nos permitira evaluar in situ el estado y comportamiento del catalizador.

  17. Uso de l1 en entornos de aprendizaje de inglés como lengua extranjera (EFL

    Directory of Open Access Journals (Sweden)

    Boris Cadena Murga

    2018-05-01

    Full Text Available Los idiomas extranjeros se han enseñado a través de diversos métodos y enfoques. El papel de los docentes se ha transformado de ser el centro de la actividad de enseñanza a facilitador del aprendizaje. Una de las principales controversias que surge en este tema es el uso de L1 mientras el inglés como idioma extranjero o segundo idioma (L2 se facilita a los estudiantes. Algunos maestros dependen en gran medida de la lengua materna y otros la proscriben por completo. El objetivo principal de este trabajo fue analizar las percepciones de los instructores ecuatorianos sobre el uso del español durante las clases de inglés en dos universidades en Ecuador. En estos casos, el uso de L1 por parte de los profesores durante la instrucción se comparó entre los grupos. En cada grupo se observó la percepción de los estudiantes sobre el uso del español. Una parte de la población del estudio consistió en tres profesores de lengua inglesa como lengua extranjera. Los grupos de estudiantes de EFL, de Quito y Riobamba se caracterizaron de manera diferente en varios aspectos como: nivel de competencia, edad, nivel social. Los investigadores completaron una ficha de observación durante todas las sesiones. Los instructores y estudiantes que participaron en esta investigación fueron encuestados inmediatamente después de la última lección observada. El resultado producido a partir de esta recopilación y análisis de datos guiará a los maestros a encontrar una mejor respuesta sobre las controversias en el uso de L1 durante la instrucción de L2.

  18. Effect of Al Hot-Dipping on High-Temperature Corrosion of Carbon Steel in N2/0.1% H2S Gas

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Abro

    2016-02-01

    Full Text Available High-temperature corrosion of carbon steel in N2/0.1% H2S mixed gas at 600–800 °C for 50–100 h was studied after hot-dipping in the aluminum molten bath. Hot-dipping resulted in the formation of the Al topcoat and the Al-Fe alloy layer firmly adhered on the substrate. The Al-Fe alloy layer consisted primarily of a wide, tongue-like Al5Fe2 layer and narrow Al3Fe layer. When corroded at 800 °C for 100 h, the Al topcoat partially oxidized to the protective but non-adherent α-Al2O3 layer, and the interdiffusion converted the Al-Fe alloy layer to an (Al13Fe4, AlFe3-mixed layer. The interdiffusion also lowered the microhardness of the hot-dipped steel. The α-Al2O3 layer formed on the hot-dipped steel protected the carbon steel against corrosion. Without the Al hot-dipping, the carbon steel failed by forming a thick, fragile, and non-protective FeS scale.

  19. [4,6-Dimethyl­pyrimidine-2(1H)-thione-κS]iodidobis(triphenyl­phosphane-κP)copper(I)

    Science.gov (United States)

    Pakawatchai, Chaveng; Wattanakanjana, Yupa; Choto, Patcharanan; Nimthong, Ruthairat

    2012-01-01

    In the mononuclear title complex, [CuI(C6H8N2S)(C18H15P)2], the CuI ion is in a slightly distorted tetra­hedral coordination geometry formed by two P atoms from two triphenyl­phosphane ligands, one S atom from a 4,6-dimethyl­pyrimidine-2(1H)-thione ligand and one iodide ion. There is an intra­molecular N—H⋯I hydrogen bond. In the crystal, π–π stacking inter­actions [centroid–centroid distance = 3.594 (1) Å] are observed. PMID:22719327

  20. A facile synthesis of Zn(x)Cd(1-x)S/CNTs nanocomposite photocatalyst for H2 production.

    Science.gov (United States)

    Wang, Lei; Yao, Zhongping; Jia, Fangzhou; Chen, Bin; Jiang, Zhaohua

    2013-07-21

    The sulfide solid solution has become a promising and important visible-light-responsive photocatalyst for hydrogen production nowadays. Zn(x)Cd(1-x)S/CNT nanocomposites were synthesized to improve the dispersion, adjust the energy band gap, and enhance the separation of the photogenerated electrons and holes. The as-prepared photocatalysts were characterized by scanning electron-microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectra (UV-visible), respectively. And the effects of CNTs on structure, composition and optical absorption property of the sulfide solid solutions were investigated along with their inherent relationships. For Zn0.83Cd0.17S/CNTs, sulfide solid solution is assembled along the CNTs orderly, with a diameter of 100 nm or so. XPS analysis shows that there is bonding effect between the solid solutions and the CNTs due to the strong adsorption of Zn(2+) and Cd(2+) on the surface of CNTs. There are two obvious absorption edges for Zn0.83Cd0.17S/CNTs, corresponding to two kinds of sulfide solid solutions with different molar ratios of Zn/Cd. The hybridization of solid solutions with CNTs makes the absorption spectrum red shift. The photocatalytic property was evaluated by splitting Na2S + Na2SO3 solution into H2, and the highest rate of H2 evolution of 6.03 mmol h(-1) g(-1) was achieved over Zn0.83Cd0.17S/CNTs. The high activity of photocatalytic H2 production is attributed to the following factors: (1) the optimum band gap and a moderate position of the conduction band (which needs to match the irradiation spectrum of the Xe lamp best), (2) the efficient separation of photogenerated electrons and holes by hybridization, and (3) the improvement of the dispersion of nanocomposites by assembling along the CNTs as well.

  1. Avaliação da durabilidade de processos fotocatalíticos aplicados comos-tratamentos em substratos de argamassa

    Directory of Open Access Journals (Sweden)

    Guilherme Custódio Garcia Junior

    Full Text Available ResumoOs processos fotocatalíticos estão sendo estudados e incorporados a sistemas construtivos objetivando melhoria da qualidade da água e do ar. No entanto pairam dúvidas sobre qual o grau de atuação da fotocatálise nos substratos e sobretudo por quanto tempo continua ocorrendo e qual sua intensidade. O método proposto consiste em, através de um pós-tratamento superficial associado a um processo fotocatalítico, obter a simultaneidade das ações dos efeitos hidrofóbicos e hidrofílicos. O presente artigo propõe avaliar a durabilidade de processos fotocatalíticos por meio de um programa experimental, em que corpos de provas de argamassa para revestimento externo após serem pós-tratados e manchados com soluções de azul de metileno (C16H18N3SCl na concentração de 1% em água deionizada e em álcool etílico 92,8°(C2H6O, foram submetidos a 200 ciclos de envelhecimento artificial (molhagem, exposição à radiações infravermelho e ultravioleta. Os resultados apontam: 1 o aumento da concentração de dióxido de titânio acelera os processos de degradação do azul de metileno; 2 os tratamentos superficiais com dispersões aquosas de TiO2 apresentaram queda de desempenho ao longo dos ensaios; 3 o hidrofugante à base de silicone mostrou um bom potencial como agente de fixação do semicondutor.

  2. Sediment Resuspension and Deposition on Seagrass Leaves Impedes Internal Plant Aeration and Promotes Phytotoxic H2S Intrusion

    Directory of Open Access Journals (Sweden)

    Kasper E. Brodersen

    2017-05-01

    Full Text Available HIGHLIGHTS:Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H2S.Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended particles onto seagrass leaves potentially impeding gas exchange with the surrounding water. We used microsensors to determine O2 fluxes and diffusive boundary layer (DBL thickness on leaves of the seagrass Zostera muelleri with and without fine sediment particles, and combined these laboratory measurements with in situ microsensor measurements of tissue O2 and H2S concentrations. Net photosynthesis rates in leaves with fine sediment particles were down to ~20% of controls without particles, and the compensation photon irradiance increased from a span of 20–53 to 109–145 μmol photons m−2 s−1. An ~2.5-fold thicker DBL around leaves with fine sediment particles impeded O2 influx into the leaves during darkness. In situ leaf meristematic O2 concentrations of plants exposed to fine sediment particles were lower than in control plants and exhibited long time periods of complete meristematic anoxia during night-time. Insufficient internal aeration resulted in H2S intrusion into the leaf meristematic tissues when exposed to sediment resuspension even at relatively high night-time water-column O2 concentrations. Fine sediment particles that settle on seagrass leaves thus negatively affect internal tissue aeration and thereby the plants' resilience against H2S intrusion.

  3. Effect of H{sub 2}S on the thermodynamic stability and electrochemical performance of Ni cermet-type of anodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Venkateswara Rao, M.

    2006-11-15

    For SOFCs to be main means of power generation, they should be able to exploit wide variety of fuels. Among Ni-cermets, Ni-YSZ is the state-of-the-art materials for SOFC-anode which is the fuel electrode. But sulphur impurity present in different gaseous fuels (e.g Biogas), depending on its concentration, is highly poisonous to the stability and electrochemical performance of the Ni catalyst in the cermet anodes. Thus in this study the microstructural stability of Ni-YSZ, Ni-CGO and Ni-LSGM cermets in H{sub 2}S-containing hydrogen gas is studied in the intermediate temperature range of SOFC operation. Thermodynamic modelling of Ni-S-O-H quaternary system was performed for the calculation of thermodynamic stability and sulphur-tolerance limit of Ni in the gaseous atmosphere made up of H, O and S. The effect of presence H{sub 2}S in fuel gas, in the concentrations well below the thermodynamic tolerance limit, on the electrochemical performance of the anodes is studied by using model Ni-patterned electrodes on YSZ and LSGM. Thermodynamic modelling of the Ni-S-O-H quaternary was performed by employing CALPHAD methodology. The modelling of Ni-S binary phase diagram was performed by using sublattice models for the non-stoichiometric phases. The optimised binaries of Ni-O, and Ni-H were taken from the literature. The Ni-O-S and Ni-O-H ternaries were extrapolated from the lower order binaries. In Ni-O-S ternary, NiSO{sub 4} is the only ternary compound present. The ternary compounds, Ni(OH){sub 2} and NiOOH in the Ni-O-H ternary were considered as stoichiometric line compounds. The model parameters of the ternary compounds were optimised using the experimental data. The Ni-S-O-H quaternary was calculated by extrapolation method as employed in the CALPHAD methodology. Inorder to understand the H{sub 2}-oxidation mechanism and the role played by the electrolyte in the reaction mechanism, symmetrical cells of Ni-patterned YSZ single crystals with different crystallographic

  4. Practical criterion for the determination of translation factors. II. Application to He/sup 2 +/+H(1s) collisions

    Energy Technology Data Exchange (ETDEWEB)

    Errea, L.F.; Gomez-Llorente, J.M.; Mendez, L.; Riera, A.

    1985-10-01

    An illustration is reported on the use of the Euclidean norm as a criterion of the quality of translation factors in the molecular model of atomic collisions. The relation between our norm and the deviation vector of Chang and Rapp (J. Chem. Phys. 59, 572 (1973)), and the computational simplicity of the calculation and minimization of the former quantity, are very appealing features of our approach. To show how the norm method can be applied, the He/sup 2 +/+H(1s)..-->..He/sup +/(2s,2p )+H/sup +/ reaction is treated.

  5. Los profesionales de secundaria, como factores de riesgo en el síndrome de Burnout

    OpenAIRE

    Giselle León-León

    2011-01-01

    Recibido 21 de julio de 2010 • Aceptado 31 de agosto de 2010 • Corregido 03 de octubre de 2010     Este artículo aborda el síndrome de Bournout, entendido como un trastorno de la adaptación ante el estrés crónico laboral que logra desencadenar síntomas físicos y psicológicos, los cuales dañan significativamente la ejecución profesional de los individuos que prestan servicios, en este particular, el trabajo de los docentes de secundaria, los cuales se describen como vulnerables por...

  6. Los profesionales de secundaria, como factores de riesgo en el síndrome de Burnout

    OpenAIRE

    León-León, Giselle

    2011-01-01

    Recibido 21 de julio de 2010 • Aceptado 31 de agosto de 2010 • Corregido 03 de octubre de 2010  Este artículo aborda el síndrome de Bournout, entendido como un trastorno de la adaptación ante el estrés crónico laboral que logra desencadenar síntomas físicos y psicológicos, los cuales dañan significativamente la ejecución profesional de los individuos que prestan servicios, en este particular, el trabajo de los docentes de secundaria, los cuales se describen como vulnerables por atender a adol...

  7. Ethanol oxidation reactions catalyzed by water molecules: CH3CH2OH+n H2O→ CH3CHO+ H2+n H2O (n=0,1,2)

    Science.gov (United States)

    Takahashi, H.; Hisaoka, S.; Nitta, T.

    2002-09-01

    Ab initio density functional theory calculations have been performed to investigate the catalytic role of water molecules in the oxidation reaction of ethanol: CH3CH2OH+n H2O→ CH3CHO+ H2+n H2O (n=0,1,2) . The results show that the potential energy barrier for the reaction is 88.0 kcal/mol in case of n=0, while it is reduced by ˜34 kcal/mol when two water molecules are involved ( n=2) in the reaction. As a result, the rate constant increases to 3.31×10 -4 s-1, which shows a significant catalytic role of water molecules in the ethanol oxidation reactions.

  8. Process studies for a new method of removing H/sub 2/S from industrial gas streams

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, D.W.; Lynn, S.

    1986-07-01

    A process for the removal of hydrogen sulfide from coal-derived gas streams has been developed. The basis for the process is the absorption of H/sub 2/S into a polar organic solvent where it is reacted with dissolved sulfur dioxide to form elemental sulfur. After sulfur is crystallized from solution, the solvent is stripped to remove dissolved gases and water formed by the reaction. The SO/sub 2/ is generated by burning a portion of the sulfur in a furnace where the heat of combustion is used to generate high pressure steam. The SO/sub 2/ is absorbed into part of the lean solvent to form the solution necessary for the first step. The kinetics of the reaction between H/sub 2/S and SO/sub 2/ dissolved in mixtures of N,N-Dimethylaniline (DMA)/ Diethylene Glycol Monomethyl Ether and DMA/Triethylene Glycol Dimethyl Ether was studied by following the temperature rise in an adiabatic calorimeter. This irreversible reaction was found to be first-order in both H/sub 2/S and SO/sub 2/, with an approximates heat of reaction of 28 kcal/mole of SO/sub 2/. The sole products of the reaction appear to be elemental sulfur and water. The presence of DMA increases the value of the second-order rate constant by an order of magnitude over that obtained in the glycol ethers alone. Addition of other tertiary aromatic amines enhances the observed kinetics; heterocyclic amines (e.g., pyridine derivatives) have been found to be 10 to 100 times more effective as catalysts when compared to DMA.

  9. Highly active sulfided CoMo catalysts supported on (ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3} ternary oxides

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, José, E-mail: jeaguila@imp.mx [Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, Gustavo A. Madero, México, D.F. 07730 (Mexico); De Los Reyes, José A., E-mail: jarh@xanum.uam.mx [Area de Ing. Química, UAM – Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México, D.F. 09340 (Mexico); Ulín, Carlos A. [Area de Ing. Química, UAM – Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México, D.F. 09340 (Mexico); Barrera, María C., E-mail: mcbdgavilan@gmail.com [Facultad de Ciencias Químicas, Universidad Veracruzana, Av. Universidad km. 7.5, Col. Santa Isabel, Coatzacoalcos, Veracruz, México, D.F. 96538 (Mexico)

    2013-12-16

    (ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3} ternary oxide at 20 mol% Al{sub 2}O{sub 3} (80% ZrO{sub 2}–TiO{sub 2}, in turn at 40–60 mol ratio) prepared by controlled co-precipitation (by urea thermal decomposition) of zirconium (ZrOCl{sub 2}·8H{sub 2}O) and titanium (TiCl{sub 4}) chlorides over a ground alumina substrate constitutes a promising material to be used as carrier of sulfided hydrodesulfurization (HDS) catalysts. After calcining (at 500 °C), the ternary oxide presented textural properties (S{sub g} = 387 m{sup 2} g{sup −1}, V{sub p} = 0.74 ml g{sup −1}, mean pore diameter = 7.6 nm) suitable to its utilization as carrier of catalysts applied in the oil-derived middle distillates HDS. As determined by temperature programmed-reduction and Raman and UV–vis spectroscopies ZrO{sub 2}–TiO{sub 2} deposition over alumina substrate resulted in decreased proportion of Mo{sup 6+} species in tetrahedral coordination on the oxidic impregnated material. As those species constitute hardly reducible precursors, their diminished concentration could be reflected in enhanced amount of Mo species susceptible of activation by sulfiding (H{sub 2}S/H{sub 2} at 400 °C) over our ternary carrier. Limiting the concentration of zirconia-titania (at 40–60 mol ratio) to 20 mol% in the mixed oxides support allowed the preparation of highly active promoted (by cobalt, at Co/(Co + Mo) = 0.3) MoS{sub 2} phase (at 2.8 atoms/nm{sup 2}), that formulation showing excellent properties in hydrodesulfurization (HDS) of both dibenzothiophene and highly-refractory 4,6-dimethyl-dibenzothiophene. Due to alike yields to various HDS products over CoMo/(ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3} and the corresponding Al{sub 2}O{sub 3}-supported formulation, presence of similar actives sites over those catalysts was strongly suggested. It seemed that enhanced concentration of octahedral Mo{sup 6+} over the oxidic impregnated precursor with (ZrO{sub 2}–TiO{sub 2})/Al{sub 2}O{sub 3

  10. Velocity dependence of the cross sections for Penning, rearrangement, and total ionization of H2 and D2 molecules by He (23S) and He (21S) metastable atoms

    International Nuclear Information System (INIS)

    Fort, J.; Bolzinger, T.; Corno, D.; Ebding, T.; Pesnelle, A.

    1978-01-01

    The velocity dependence of both the Penning and rearrangement ionization cross sections sigma/sub PI/ and sigma/sub RI/ for H 2 /sup ts+/ and HeH + ion production, as well as total ionization cross section sigma/sub TI/, resulting from the collisions of He (2 1 S) and He (2 3 S) with H 2 is measured over the relative-velocity range 2400--5300 m/sec (0.04--0.20 eV energy range) in a crossed-beam experiment by a time-of-flight technique. Characteristic cross-section ratios sigma/sub RI//sigma/sub TI/ and the relative magnitude of the cross sections sigma/sub RI/, sigma/sub PI/, and sigma/sub TI/ are reported. Comparison with some recent theoretical calculations is made; we observe a fair agreement in the triplet case except for sigma/sub RI/, but a strong difference in the singlet case

  11. Synthesis and characterisation of pure C(-A)-S-H phases

    International Nuclear Information System (INIS)

    L'Hopital, E.; Lothenbach, B.; Le Saout, G.; Kulik, D.A.; Scrivener, K.

    2015-01-01

    The construction of nuclear power plants requires huge quantity of cement and the cement production generates about 8% of global man-made CO 2 emissions. One way of reducing the concrete's CO 2 contribution is to lower its CO 2 generation and energy consumption by a partial replacement of clinker with supplementary cementitious materials (SCMs). Common SCMs such as blast furnace slag or fly ash contain more silicon and aluminium than Portland cement, so that the hydrates formed are different than in Portland cements, which might affect the concrete mechanical properties. The most important phase formed during the reaction of Portland cement with water is calcium silicate hydrate, C-S-H. In the presence of SCMs, C-S-H can have different composition compared to C-S-H in Portland cements. The present work focuses on synthesis of pure C(-A)- S-H at a Ca/Si ratio equal to 1 in presence of different quantities of aluminium (Al/Si atomic ratio from 0 to 0.05) to determine the aluminium incorporation in C-S-H. The absence of any other solids and the low aluminium concentrations measured in the solution clearly showed an uptake of aluminium within the C-(A)-S-H phase. The presence of aluminium increased the interlayer distance, indicating an uptake of aluminium in the C-(A)-S-H structure. The uptake of aluminium was more pronounced at higher dissolved aluminium concentrations, consistent with the formation of a solid solution between C-S-H and C-A-S-H. The presence of aluminium led to a decrease of the calcium concentrations, while the silica and aluminium concentrations increased

  12. Estudio de las características fisicoquímicas de los carbones mesoporosos obtenidos utilizando sílica mesoporosa tipo SBA-16 como molde

    Directory of Open Access Journals (Sweden)

    Leidy Hoyos

    2010-01-01

    Full Text Available En este trabajo se determinan las características porosas y químicas de carbones mesoporosos sintetizados utilizando sílica mesoporosa tipo SBA- 16 como molde y se correlacionan estas características con la capacidad de adsorció de colorantes, lo cual a su vez se constituye en una técnica mas de caracterización fisicoquímica de estos materiales. Se utilizan dos moldes silíceos tipo SBA-16 con diferencias en su porosidad y sacarosa y etileno como fuente de carbón. Se encuentra que el tamaño, volumen de poro y área superficial de estos materiales se pueden modular mediante la selección del molde pero no sus características químicas. Los carbones mesoporosos se sintetizan por el método húmedo, en el cual se utiliza sacarosa como fuente de carbono o por deposición de vapores de etileno utilizando dos sílicas mesporosas con diferentes características de porosidad.

  13. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Jianbo Sun

    2016-03-01

    Full Text Available The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels.

  14. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Science.gov (United States)

    Sun, Jianbo; Sun, Chong; Lin, Xueqiang; Cheng, Xiangkun; Liu, Huifeng

    2016-01-01

    The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH)3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels. PMID:28773328

  15. A model to explain high values of pH in an alkali sodic soil Modelo para explicar valores elevados de pH em um solo sódico alcalino

    Directory of Open Access Journals (Sweden)

    José Guerrero-Alves

    2002-12-01

    Full Text Available For alkali sodic soils (pH>8.5, the "hydrolysis of exchangeable sodium" has been used as a possible explanation for the alkalinity production and rise in pH of these soils. As an alternative to this hypothesis, a model was developed to simulate and to explain that the alkalinity production and rise in pH is possible in a soil that accumulates alkaline sodium salts and CaCO3. Several simulations were performed by using different combinations of CO2 partial pressures (P, presence or absence of MgCO3, along with experimental values of exchangeable sodium percentage (ESP and ion concentrations in saturation extracts from an alkali sodic soil (named Pantanal. A hypothetical system with similar conditions to the Pantanal soil but with a Gapon selectivity coefficient (KG of 0.01475 (mmol L-1-1/2 was also considered. Good agreement was obtained between experimental and predicted values for pH and ion concentrations in the soil solution when the model (without MgCO3 was applied to the Pantanal soil. However, KG values calculated for the Pantanal soil were generally higher than 0.01475 (mmol L-1-1/2. Moreover, high pH values and elevated ionic strength were obtained when a KG of 0.01475 (mmol L-1-1/2 was used at high ESP (similar to those found in the Pantanal soil. KG values obtained for the Pantanal soil and the results obtained in the simulation of the hypothetical system are suggesting that a value higher than 0.01475 (mmol L-1-1/2 should be used to adequately simulate the behavior of the Pantanal soil at low ionic strength and high ESP values.Em solos alcalino sódicos (pH>8,5, a "hidrólise de sódio trocável" tem sido usada como uma possível explicação para a produção de álcali e elevação do pH nestes solos. Como uma alternativa a essa hipótese, um modelo foi desenvolvido para simular e explicar que a produção de álcali e elevação do pH é possível num solo que acumula sais alcalinos de sódio e CaCO3. Várias simulações foram

  16. Anti-Ageing Effects of Sonchus oleraceus L. (pūhā) Leaf Extracts on H2O2-Induced Cell Senescence

    DEFF Research Database (Denmark)

    Ou, Zong-Quan; Rades, Thomas; McDowell, Arlene

    2015-01-01

    Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae) leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H2O2......-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H2O2. Cells were treated with S. oleraceus extracts before or after H2O2 stress. The senescence- associated β-galactosidase (SA-β-gal) activity was used to indicate cell senescence. S....... oleraceus extracts showed higher cellular antioxidant activity than chlorogenic acid in WI-38 cells. S. oleraceus extracts suppressed H2O2 stress-induced premature senescence in a concentration-dependent manner. At 5 and 20 mg/mL, S. oleraceus extracts showed better or equivalent effects of reducing stress...

  17. Effects of rehydration nutrients on H2S metabolism and formation of volatile sulfur compounds by the wine yeast VL3.

    Science.gov (United States)

    Winter, Gal; Henschke, Paul A; Higgins, Vincent J; Ugliano, Maurizio; Curtin, Chris D

    2011-11-02

    In winemaking, nutrient supplementation is a common practice for optimising fermentation and producing quality wine. Nutritionally suboptimal grape juices are often enriched with nutrients in order to manipulate the production of yeast aroma compounds. Nutrients are also added to active dry yeast (ADY) rehydration media to enhance subsequent fermentation performance. In this study we demonstrate that nutrient supplementation at rehydration also has a significant effect on the formation of volatile sulfur compounds during wine fermentations. The concentration of the 'fruity' aroma compounds, the polyfunctional thiols 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA), was increased while the concentration of the 'rotten egg' aroma compound, hydrogen sulfide (H2S), was decreased. Nutrient supplementation of the rehydration media also changed the kinetics of H2S production during fermentation by advancing onset of H2S production. Microarray analysis revealed that this was not due to expression changes within the sulfate assimilation pathway, which is known to be a major contributor to H2S production. To gain insight into possible mechanisms responsible for this effect, a component of the rehydration nutrient mix, the tri-peptide glutathione (GSH) was added at rehydration and studied for its subsequent effects on H2S formation. GSH was found to be taken up during rehydration and to act as a source for H2S during the following fermentation. These findings represent a potential approach for managing sulfur aroma production through the use of rehydration nutrients.

  18. Modeling Phase Equilibria for Acid Gas Mixtures Using the CPA Equation of State. I. Mixtures with H2S

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    (water, methanol, and glycols) are modeled assuming presence or not of cross-association interactions. Such interactions are accounted for using either a combining rule or a cross-solvation energy obtained from spectroscopic data. Using the parameters obtained from the binary systems, one ternary......The Cubic-Plus-Association (CPA) equation of state is applied to a large variety of mixtures containing H2S, which are of interest in the oil and gas industry. Binary H2S mixtures with alkanes, CO2, water, methanol, and glycols are first considered. The interactions of H2S with polar compounds...... and three quaternary mixtures are considered. It is shown that overall excellent correlation for binary, mixtures and satisfactory prediction results for multicomponent systems are obtained. There are significant differences between the various modeling approaches and the best results are obtained when...

  19. Initial heats of H{sub 2}S adsorption on activated carbons: Effect of surface features

    Energy Technology Data Exchange (ETDEWEB)

    Bagreev, A.; Adib, F.; Bandosz, T.J.

    1999-11-15

    The sorption of hydrogen sulfide was studied on activated carbons of various origins by means of inverse gas chromatography at infinite dilution. The conditions of the experiment were dry and anaerobic. Prior to the experiments the surface of some carbon samples was oxidized using either nitric acid or ammonium persulfate. Then the structural parameters of carbons were evaluated from the sorption of nitrogen. From the IGC experiments at various temperatures, heats of adsorption were calculated. The results showed that the heat of H{sub 2}S adsorption under dry anaerobic conditions does not depend on surface chemistry. The dependence of the heat of adsorption on the characteristic energy of nitrogen adsorption calculated from the Dubinin-Raduskevich equation was found. This correlation can be used to predict the heat of H{sub 2}S adsorption based on the results obtained from nitrogen adsorption.

  20. Atmospheric monitoring in H.E.S.S.

    Directory of Open Access Journals (Sweden)

    Hahn J.

    2015-01-01

    Full Text Available Instruments applying the IACT method, such as H.E.S.S. (High Energy Stereoscopic System, observe VHE (very high energy, E > 100 GeV photons indirectly, using the Earth's atmosphere as a calorimeter. In the H.E.S.S. data reconstruction, the properties of this component are estimated by Monte Carlo simulations of a yearly averaged atmosphere density profile. Deviations of the real atmospheric conditions from this assumed atmospheric model will result in a biased reconstruction of the primary gamma-ray energy and thus the resulting source spectrum. In order to keep the corresponding systematic effects to a minimum, H.E.S.S. operates a set of atmospheric monitoring devices that allows it to characterise the atmospheric conditions during data taking. This information in turn is then used in data selection. Here, a short overview with respect to their usage during source observation and a posteriori analysis data selection will be presented.

  1. Identification of Shewanella baltica as the most important H2S-producing species during iced storage of Danish marine fish.

    Science.gov (United States)

    Fonnesbech Vogel, Birte; Venkateswaran, Kasthuri; Satomi, Masataka; Gram, Lone

    2005-11-01

    Shewanella putrefaciens has been considered the main spoilage bacteria of low-temperature stored marine seafood. However, psychrotropic Shewanella have been reclassified during recent years, and the purpose of the present study was to determine whether any of the new Shewanella species are important in fish spoilage. More than 500 H2S-producing strains were isolated from iced stored marine fish (cod, plaice, and flounder) caught in the Baltic Sea during winter or summer time. All strains were identified as Shewanella species by phenotypic tests. Different Shewanella species were present on newly caught fish. During the warm summer months the mesophilic human pathogenic S. algae dominated the H2S-producing bacterial population. After iced storage, a shift in the Shewanella species was found, and most of the H2S-producing strains were identified as S. baltica. The 16S rRNA gene sequence analysis confirmed the identification of these two major groups. Several isolates could only be identified to the genus Shewanella level and were separated into two subgroups with low (44%) and high (47%) G+C mol%. The low G+C% group was isolated during winter months, whereas the high G+C% group was isolated on fish caught during summer and only during the first few days of iced storage. Phenotypically, these strains were different from the type strains of S. putrefaciens, S. oneidensis, S. colwelliana, and S. affinis, but the high G+C% group clustered close to S. colwelliana by 16S rRNA gene sequence comparison. The low G+C% group may constitute a new species. S. baltica, and the low G+C% group of Shewanella spp. strains grew well in cod juice at 0 degrees C, but three high G+C Shewanella spp. were unable to grow at 0 degrees C. In conclusion, the spoilage reactions of iced Danish marine fish remain unchanged (i.e., trimethylamine-N-oxide reduction and H2S production); however, the main H2S-producing organism was identified as S. baltica.

  2. Primordial Synthesis of Amines and Amino Acids in a 1958 Miller H2S-Rich Spark Discharge Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordia! environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

  3. Safe, reliable desulfurization of high and very high H{sub 2}S loadings by UgnCleanTubes {sup registered}; Sichere, zuverlaessige Entschwefelung hoher und sehr hoher H{sub 2}S-Beladungen durch UgnCleanTubes {sup registered}

    Energy Technology Data Exchange (ETDEWEB)

    Zoelsmann, Herbert [UGN-Umwelttechnik GmbH, Gera (Germany); Hilgert, Walter [Rietzler-Gruppe GmbH, Nuernberg (Germany)

    2016-08-01

    UgnCleanPellets {sup registered} S 3.5 for complete, safe desulfurization of biogas/biogenic fuel gases (hydrolysis and pyrolysis gas, landfill gas, sewage gas,..), natural gas and associated petroleum gases and industrial production exhaust gases are market introduced and tested worldwide. In particular, the complete surrender of gas cooling, gas drying and gas reheating, the H{sub 2}S removal to zero level and proven in practice loading capacity of up to % 80 percent characterize the UgnCleanPellets {sup registered} S 3.5 external as a cost-effective, efficient and sustainable desulfurization medium. The further development of the pellets to the UgnCleanTubes {sup registered} S 3.5 - that is, to internally hollow pellets with correspondingly enlarged, outer surface - is the next logical step to further improve performance whilst fully retaining the advantages of pellets. [German] UgnCleanPellets {sup registered} S 3.5 zur vollstaendigen, sicheren Entschwefelung von Biogas/biogenen Brenngasen (Hydrolyse- und Pyrolysegas, Deponiegas, Klaergas,...), Erdgas und Erdoelbegleitgasen sowie industriellen Produktionsabgasen sind markteingefuehrt und weltweit erprobt. Insbesondere der vollstaendige Verzicht auf Gaskuehlung, Gastrocknung und Gaswiederaufheizung, die H{sub 2}S-Entfernung auf Nullniveau sowie die in der Praxis nachgewiesene Beladungskapazitaet von bis zu 80-Gew% zeichnen die UgnCleanPellets {sup registered} S 3.5 als ein kostenguenstiges, effizientes und nachhaltiges externes Entschwefelungsmedium aus. Die Weiterentwicklung der Pellets zu den UgnCleanTubes {sup registered} S 3.5 - d.h. zu innen hohlen Pellets mit entsprechend vergroesserter, aeusserer Oberflaeche - ist der naechste konsequente Schritt zur weiteren Leistungssteigerung bei vollstaendiger Beibehaltung der Vorteile der Pellets.

  4. Herschel Observations of EXtra-Ordinary Sources: H2S as a Probe of Dense Gas and Possibly Hidden Luminosity Toward the Orion KL Hot Core

    Science.gov (United States)

    Crockett, N. R.; Bergin, E. A.; Neill, J. L.; Black, J. H.; Blake, G. A.; Kleshcheva, M.

    2014-02-01

    We present Herschel/HIFI observations of the light hydride H2S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H2 32S, H2 34S, and H2 33S, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H2S follow straight lines given the uncertainties and yield T rot = 141 ± 12 K. This indicates H2S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E up >~ 1000 K) are likely populated primarily by radiation pumping. We derive a column density, N tot(H2 32S) = 9.5 ± 1.9 × 1017 cm-2, gas kinetic temperature, T kin = 120+/- ^{13}_{10} K, and constrain the H2 volume density, n_H_2 >~ 9 × 10 7 cm-3, for the H2S emitting gas. These results point to an H2S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H2S ortho/para ratio of 1.7 ± 0.8 and set an upper limit for HDS/H2S of <4.9 × 10 -3. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  5. Dual Functional Core-Shell Fluorescent Ag2S@Carbon Nanostructure for Selective Assay of E. coli O157:H7 and Bactericidal Treatment.

    Science.gov (United States)

    Wang, Ning; Wei, Xing; Zheng, An-Qi; Yang, Ting; Chen, Ming-Li; Wang, Jian-Hua

    2017-03-24

    A dual functional fluorescent core-shell Ag 2 S@Carbon nanostructure is prepared by a hydrothermally assisted multi-amino synthesis approach with folic acid (FA), polyethylenimine (PEI), and mannoses (Mans) as carbon and nitrogen sources (FA-PEI-Mans-Ag 2 S nanocomposite shortly as Ag 2 S@C). The nanostructure exhibits strong fluorescent emission at λ ex /λ em = 340/450 nm with a quantum yield of 12.57 ± 0.52%. Ag 2 S@C is bound to E. coli O157:H7 via strong interaction with the Mans moiety in Ag 2 S@C with FimH proteins on the fimbriae tip in E. coli O157:H7. Fluorescence emission from Ag 2 S@C/E. coli conjugate is closely related to the content of E. coli O157:H7. Thus, a novel procedure for fluorescence assay of E. coli O157:H7 is developed, offering a detection limit of 330 cfu mL -1 . Meanwhile, the Ag 2 S@C nanostructure exhibits excellent antibacterial performance against E. coli O157:H7. A 99.9% sterilization rate can be readily achieved for E. coli O157:H7 at a concentration of 10 6 -10 7 cfu mL -1 with 3.3 or 10 μg mL -1 of Ag 2 S@C with an interaction time of 5 or 0.5 min, respectively.

  6. Metal–organic frameworks to satisfy gas upgrading demands: fine-tuning the soc-MOF platform for the operative removal of H2S

    KAUST Repository

    Belmabkhout, Youssef

    2017-01-06

    A cooperative experimental/modeling strategy was used to unveil the structure/gas separation performance relationship for a series of isostructural metal-organic frameworks (MOFs) with soc-topology (square-octahedral) hosting different extra-framework counter ions (NO3-, Cl- and Br-). In3+-, Fe3+-, Ga3+-and the newly isolated Al(III)-based isostructural soc-MOF were extensively studied and evaluated for the separation-based production of high-quality fuels (i.e., CH4, C3H8 and n-C4H10) and olefins. The structural/chemical fine-tuning of the soc-MOF platform promoted equilibrium-based selectivity toward C2+ (C2H6, C2H4, C3H6 C3H8 and n-C4H10) and conferred the desired chemical stability toward H2S. The noted dual chemical stability and gas/vapor selectivity, which have rarely been reported for equilibrium-based separation agents, are essential for the production of high-purity H-2, CH4 and C2+ fractions in high yields. Interestingly, the evaluated soc-MOF analogues exhibited high selectivity for C2H4, C3H6 and n-C4H10. In particular, the Fe, Ga and Al analogues presented relatively enhanced C2+/CH4 adsorption selectivities. Notably, the Ga and Al analogues were found to be technically preferable because their structural integrities and separation performances were maintained upon exposure to H2S, indicating that these materials are highly tolerant to H2S. Therefore, the Ga-soc-MOF was further examined for the selective adsorption of H2S in the presence of CO2-and CH4-containing streams, such as refinery-off gases (ROG) and natural gas (NG). Grand canonical Monte Carlo (GCMC) simulations based on a specific force field describing the interactions between the guest molecules and the Ga sites supported and confirmed the considerably higher affinity of the Ga-soc-MOF for C2+ (as exemplified by n-C4H10) than for CH4. The careful selection of an appropriate metal for the trinuclear inorganic molecular building block (MBB), i. e., a Ga metal center, imbues the soc

  7. Resposta de plantas de melancieira irrigadas com água salina ao tratamento pré-germinativo da semente com H2O2

    Directory of Open Access Journals (Sweden)

    Auderlan de Macena Pereira

    2013-10-01

    Full Text Available Normal 0 21 false false false PT-BR X-NONE X-NONE O manejo da água é um dos fatores mais importantes para uma efetiva absorção de nutrientes, uma vez que esta pode apresentar-se com elevadas concentrações de sais, o que pode afetar o processo de absorção, bem como causar estresse oxidativo nos vegetais, devido as espécies reativas de oxigênios (EROs, principalmente H2O2. As plantas evoluíram um complexo sistema antioxidante para conter os efeitos deletérios das EROs, é possível que a pré-exposição das plantas ao H2O2 possibilite uma adaptação das mesmas. Estudando-se uma alternativa para amenizar os efeitos deletérios das EROs,objetivou-se, neste trabalho, avaliar a resposta de plantas de melancieira, irrigadas com água salina, ao tratamento pré-germinativo da semente com H2O2. O experimento foi conduzido no Centro de Ciências e Tecnologia Agroalimentar-CCTA, da UFCG-Pombal – PB. O delineamento experimental utilizado foi de blocos casualizados em parcelas subdivididas 2x5, com 4 repetições, com a parcela constando de dois níveis de salinidade da água de irrigação (S1 = água de abastecimento local, 0,32 dSm-1; e S2 =  água salina, 2,0 dS m-1 e a subparcela de sementes de melancieira tratadas com solução de H2O2 em cinco concentrações (0, 5, 10, 15 e 20 µmol L-1. As aplicações foram feitas via água de irrigação, junto à solução nutritiva a 100%, utilizada como fonte de nutrientes. O experimento foi conduzido até o início da floração (45 DAS, quando foram avaliadas as seguintes características de crescimento: Massa Fresca da Parte Aérea, Massa Seca da Parte Aérea, Número de Folhas por Planta e Comprimento da Haste Principal. Avalio-use também as características fisiológicas: Taxa de Fotossíntese, Transpiração, Condutância Estomática e Concentração de CO2 intracelular. Os dados foram submetidos à análise de variância ao nível de 5 % de probabilidade. Os níveis de salinidades da

  8. The Effect of H2S on the Performance of SOFCs using Methane Containing Fuel

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hagen, Anke

    2010-01-01

    In recent years, the interest for using biogas derived from biomass as fuel in solid oxide fuel cells (SOFCs) has increased. To maximise the biogas to electrical energy output, it is important to study the effects of the main biogas components (CH4 and CO2), minor ones and traces (e.g. H2S...

  9. Electron capture and ionization in collisions of multiply charged ions with H(2s)

    International Nuclear Information System (INIS)

    Errea, L F; Guzman, F; Illescas, Clara; Mendez, L; Pons, B; Riera, A; Suarez, J

    2007-01-01

    We present total cross sections for electron capture and ionization in collisions of B 5+ and Ne 10+ with H(2s), calculated using two methods: the semiclassical close-coupling molecular formalism and the eikonal-CTMC method. We have evaluated partial cross sections for capture into excited n-levels, required in plasma diagnostics

  10. H2@Scale Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, Mark

    2017-07-12

    'H2@Scale' is a concept based on the opportunity for hydrogen to act as an intermediate between energy sources and uses. Hydrogen has the potential to be used like the primary intermediate in use today, electricity, because it too is fungible. This presentation summarizes the H2@Scale analysis efforts performed during the first third of 2017. Results of technical potential uses and supply options are summarized and show that the technical potential demand for hydrogen is 60 million metric tons per year and that the U.S. has sufficient domestic resources to meet that demand. A high level infrastructure analysis is also presented that shows an 85% increase in energy on the grid if all hydrogen is produced from grid electricity. However, a preliminary spatial assessment shows that supply is sufficient in most counties across the U.S. The presentation also shows plans for analysis of the economic potential for the H2@Scale concept. Those plans involve developing supply and demand curves for potential hydrogen generation options and as compared to other options for use of that hydrogen.

  11. $^{3}_{\\Lambda}\\mathrm H$ and $^{3}_{\\bar{\\Lambda}} \\overline{\\mathrm H}$ production in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV

    CERN Document Server

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Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Seeder, Karin Soraya; Seger, Janet Elizabeth; Sekiguchi, Yuko; Sekihata, Daiki; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Natasha; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tanaka, Naoto; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarhini, Mohamad; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vechernin, Vladimir; Veen, Annelies Marianne; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Watanabe, Yosuke; Weber, Michael; Weber, Steffen Georg; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

    2016-03-10

    The production of the hypertriton nuclei $^{3}_{\\Lambda}\\mathrm H$ and $^{3}_{\\bar{\\Lambda}} \\overline{\\mathrm H}$ has been measured for the first time in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV with the ALICE experiment at LHC energies. The total yield, d$N$/d$y$ $\\times \\mathrm{B.R.}_{\\left( ^{3}_{\\Lambda}\\mathrm H \\rightarrow ^{3}\\mathrm{He},\\pi^{-} \\right)} = \\left( 3.86 \\pm 0.77 (\\mathrm{stat.}) \\pm 0.68 (\\mathrm{syst.})\\right) \\times 10^{-5}$ in the 0-10% most central collisions, is consistent with the predictions from a statistical thermal model using the same temperature as for the light hadrons. The coalescence parameter $B_3$ shows a dependence on the transverse momentum, similar to the $B_2$ of deuterons and the $B_3$ of $^{3}\\mathrm{He}$ nuclei. The ratio of yields $S_3$ = $^{3}_{\\Lambda}\\mathrm H$/($^{3}\\mathrm{He}$ $\\times \\Lambda/\\mathrm{p}$) was measured to be $S_3$ = 0.60 $\\pm$ 0.13 (stat.) $\\pm$ 0.21 (syst.) in 0-10% centrality events; this value is compared to different theoretic...

  12. Materiales híbridos basados en fosfato de vanadilo y polímeros conductores como cátodos en baterías reversibles de litio

    Directory of Open Access Journals (Sweden)

    Cuentas-Gallegos, A. K.

    2004-04-01

    Full Text Available Vanadyl phosphate is a well known layered inorganic phase, capable of intercalating a great variety of organic molecules. By means of an in-situ polymerisation of aniline or pyrrole between the layers of the inorganic phase, it is possible to obtain organic-inorganic hybrids. We describe the synthesis and characterization of these type of hybrids, and some preliminary results of their application as active cathodic materials for positive electrodes in reversible lithium cells.

    El fosfato de vanadilo es bien conocido como una fase inorgánica laminar capaz de intercalar una gran variedad de moléculas orgánicas. Mediante la polimerización in-situ, de anilina o pirrol, en la fase inorgánica es posible preparar materiales híbridos orgánico-inorgánicos en los que el polímero queda intercalado. Se describe la síntesis y caracterización de este tipo de híbridos y algunos resultados preliminares de su aplicación como materiales activos de cátodo en celdas reversibles de litio.

  13. Fast Response and High Sensitivity of ZnO Nanowires-Cobalt Phthalocyanine Heterojunction Based H2S Sensor.

    Science.gov (United States)

    Kumar, Ashwini; Samanta, Soumen; Singh, Ajay; Roy, Mainak; Singh, Surendra; Basu, Saibal; Chehimi, Mohmad M; Roy, Kallol; Ramgir, Niranjan; Navaneethan, M; Hayakawa, Y; Debnath, Anil K; Aswal, Dinesh K; Gupta, Shiv K

    2015-08-19

    The room temperature chemiresistive response of n-type ZnO nanowire (ZnO NWs) films modified with different thicknesses of p-type cobalt phthalocyanine (CoPc) has been studied. With increasing thickness of CoPc (>15 nm), heterojunction films exhibit a transition from n- to p-type conduction due to uniform coating of CoPc on ZnO. The heterojunction films prepared with a 25 nm thick CoPc layer exhibit the highest response (268% at 10 ppm of H2S) and the fastest response (26 s) among all samples. The X-ray photoelectron spectroscopy and work function measurements reveal that electron transfer takes place from ZnO to CoPc, resulting in formation of a p-n junction with a barrier height of 0.4 eV and a depletion layer width of ∼8.9 nm. The detailed XPS analysis suggests that these heterojunction films with 25 nm thick CoPc exhibit the least content of chemisorbed oxygen, enabling the direct interaction of H2S with the CoPc molecule, and therefore exhibit the fastest response. The improved response is attributed to the high susceptibility of the p-n junctions to the H2S gas, which manipulates the depletion layer width and controls the charge transport.

  14. Ab initio study of {sup 2}H(d,{gamma}){sup 4}He, {sup 2}H(d,p){sup 3}H, and {sup 2}H(d,n){sup 4}He reactions and the tensor force

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K.; Aoyama, S.; Suzuki, Y.; Descouvemont, P.; Baye, D. [Division of General Education, Nagaoka National College of Technology, 888 Nishikatakai, Nagaoka, Niigata, 940-8532 (Japan); Center for Academic Information Service, Niigata University, Niigata 950-2181 (Japan); Department of Physics, Niigata University, Niigata 950-2181, Japan and RIKEN Nishina Center, Wako 351-0198 (Japan); Physique Nucleaire Theorique et Physique Mathematique, C.P.229, Universite Libre de Bruxelles, B 1050 Brussels (Belgium); Physique Quantique, CP165/82, Universite Libre de Bruxelles, B-1050 Brussels (Belgium)

    2012-11-12

    The {sup 2}H(d,p){sup 3}H, {sup 2}H(d,n){sup 3}He, and {sup 2}H(d,{gamma}){sup 4}He reactions at low energies are studied with realistic nucleon-nucleon interactions in an ab initio approach. The obtained astrophysical S-factors are all in very good agreement with experiment. The most important channels for both transfer and radiative capture are all found to dominate thanks to the tensor force.

  15. N-(2-Methylphenyl-1,2-benzoselenazol-3(2H-one

    Directory of Open Access Journals (Sweden)

    Xu Zhu

    2013-10-01

    Full Text Available In the title Ebselen [systematic name: (2-phenyl-1,2-benzoisoselenazol-3-(2H-one] analogue, C14H11NOSe, the benzisoselenazolyl moiety (r.m.s. deviation = 0.0209 Å is nearly perpendicular to the N-arenyl ring, making a dihedral angle of 78.15 (11°. In the crystal, molecules are linked by C—H...O and Se...O interactions into chains along the c-axis direction. The Se...O distance [2.733 (3 Å] is longer than that in Ebselen (2.571 (3 Å].

  16. Preparation of deuteriated adipic [2H2]-, [2H4]-, [2H6]-, and [2H8]-acids by use of Kolbe electrolysis as a key reaction

    International Nuclear Information System (INIS)

    Tashiro, Masahi; Tsuzuki, Hirohisa; Mataka, Shuntaro; Goto, Hideyuki; Ogasahara, Shoji

    1990-01-01

    Using Kolbe electrolysis of methyl hydrogen [ 2 H 0 ]-, [ 2 H 2 ]-, and [ 2 H 4 ]-succinates as a key reaction, adipic [2,2- 2 H 2 ]-, [2,3- 2 H 2 ]-, [2,2,3,3- 2 H 4 ]-, [2,3,4,5- 2 H 4 ]-, [2,3,5,5- 2 H 4 ]-, [2,2,3,3,5,5- 2 H 6 ]-, and [2,2,3,3,4,4,5,5- 2 H 8 ]-acids were prepared in high deuterium contents. (author)

  17. Low-temperature solid-state preparation of ternary CdS/g-C{sub 3}N{sub 4}/CuS nanocomposites for enhanced visible-light photocatalytic H{sub 2}-production activity

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun, E-mail: xiangqj@mail.hzau.edu.cn

    2017-01-01

    Highlights: • CdS/g-C{sub 3}N{sub 4}/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C{sub 3}N{sub 4}/CuS show enhanced visible-light photocatalytic H{sub 2} evolution activity. • The enhanced photocatalytic H{sub 2} production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C{sub 3}N{sub 4}/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C{sub 3}N{sub 4}/CuS composite exhibits a high visible-light photocatalytic H{sub 2}-production rate of 57.56 μmol h{sup −1} with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na{sub 2}S/Na{sub 2}SO{sub 3} mixed aqueous solution as sacrificial agent. The ternary CdS/g-C{sub 3}N{sub 4}/CuS composites show the enhanced visible-light photocatalytic H{sub 2}-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C{sub 3}N{sub 4} in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H{sub 2}-production activity.

  18. Fast elastic e-H(2s) scattering in laser fields

    International Nuclear Information System (INIS)

    Vucic, S.; Hewitt, R.; Hewitt, R.

    1997-01-01

    A numerical method for the evaluation of the Born endash Floquet amplitude for laser-assisted scattering is proposed for the case when a large basis set is required to achieve convergence. The method is applied to analyze the elastic scattering of fast electrons by the H(2s) state in a low-intensity laser field of varying frequency and to study the resonant scattering with increasing laser intensity. While the behavior of an atom in a resonant field of low intensity is determined by virtual transitions between resonant levels, at high intensity a great number of nonresonant virtual transitions may significantly influence laser-assisted processes. As a consequence, the attenuation of resonant effects could appear, as well as the open-quotes localclose quotes stabilization of the atom against ionization. copyright 1997 The American Physical Society

  19. Influence on the life of gasturbine components when H{sub 2}S is present in the fuel

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Fredrik; Wiklund, Peter

    2012-09-15

    Objective with this project is to generate data and increase the understanding of the corrosion mechanisms that occur during exposure of nickel based super alloys and thermal barrier coatings (TBC:s) in SO{sub 2} which is the product of combustion of H{sub 2}S. This is also to be done considering environments where small concentrations of alkali sulphates are present. The overall objective with the activities within the project is to increase the commercial viability of bio-gas, which generally contains large concentrations of H{sub 2}S by testing under conditions seen by many of the more expensive components within a gas turbine. Focus during this work has been to study the degradation mechanisms of the oxides that form passive layers and protect the surface of the alloys used in gas turbines. Oxide layers growing between the ceramic top coating, which constitutes the insulation in a thermal barrier coating and the metallic bond coating were also studied. The growth and composition of this oxide layer is critical for the adherence of the top coating. Cyclic exposure testing with and without additions of SO{sub 2} and approximately 10 ppm alkali sulphate has been used to assess the lifetime of five nickel-base super alloys in conditions simulating gas turbine operating on fuel containing 3Wt % H{sub 2}S. The testing has been conducted above the dew point of the alkali sulphate.

  20. El reciclaje de nitratos a partir del centrado como estrategia para mitigar la liberación de olores

    OpenAIRE

    Kweinor Tetteh, Emmanuel

    2017-01-01

    En este trabajo fin de grado se utilizó un biorreactor integrado a escala piloto (anaeróbico-anóxico-aeróbico) con un volumen de trabajo de 12,9 L acoplado sedimentador de separación de biomasa para tratar aguas residuales mediante un proceso A2O. Se evaluó a escala laboratorio la recirculación de nitratos (provenientes de la oxidación de centrados) como estrategia de prevención de olores, estudiando tanto el proceso de tratamiento de agua residual como las cinéticas de oxidación de H2S con n...

  1. The singlet-triplet energy gap in divalent three, five and seven-membered cyclic C2H2M, C4H4M and C6H6M (M = C, Si, Ge, Sn AND Pb

    Directory of Open Access Journals (Sweden)

    E. Vessally

    2009-08-01

    Full Text Available Total energy gaps, ∆Et–s, enthalpy gaps, ∆Ht–s, and Gibbs free energy gaps, ∆Gt–s, between singlet (s and triplet (t states were calculated for three, five and seven-membered cyclic C2H2M, C4H4M and C6H6M (M = C, Si, Ge, Sn and Pb at B3LYP/6-311++G**. The singlet-triplet free energy gaps, ∆Gt–s, for C2H2M (M = C, Si, Ge, Sn and Pb are found to be increased in the order: C2H2Si > C2H2C > C2H2Ge > C2H2Sn > C2H2Pb. The ∆Gt–s of C4H4M are found to be increased in the order: C4H4Pb > C4H4Sn > C4H4Ge > C4H4Si > C4H4C. Also, the ∆Gt–s of C6H6M are determined in the order: C6H6Pb > C6H6Ge ≥ C6H6Sn > C6H6Si > C6H6C. The most stable conformers of C2H2M, C4H4M and C6H6M are proposed for both the singlet and triplet states. Nuclear independent chemical shifts (NICS calculations were carried out for determination of aromatic character. The geometrical parameters are calculated and discussed.

  2. System and process for capture of H.sub.2S from gaseous process streams and process for regeneration of the capture agent

    Science.gov (United States)

    Heldenbrant, David J; Koech, Phillip K; Rainbolt, James E; Bearden, Mark D; Zheng, Feng

    2014-02-18

    A system and process are disclosed for selective removal and recovery of H.sub.2S from a gaseous volume, e.g., from natural gas. Anhydrous organic, sorbents chemically capture H.sub.2S gas to form hydrosulfide salts. Regeneration of the capture solvent involves addition of an anti-solvent that releases the captured H.sub.2S gas from the capture sorbent. The capture sorbent and anti-solvent are reactivated for reuse, e.g., by simple distillation.

  3. Effects of H2S and process conditions in the synthesis of mixed alcohols from syngas over alkali promoted cobalt-molybdenum sulfide

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Mortensen, Peter Mølgaard; Trane, Rasmus

    2009-01-01

    pressures of H2 and CO are also investigated. With or without H2S in the feed the pre-sulfided catalyst requires an initiation period to reach a stabilized behavior, but the duration of this period depends upon the H2S level. Operation with a feed containing more than 103 ppmv H2S leads to a fairly rapid...... coverage and low hydrogen coverage. Hydrogen sulfide in the syngas feed generally promotes chain growth for both alcohols and hydrocarbons, but lowers the alcohol selectivity by enhancing the hydrocarbon formation. The highest alcohol productivity reached in these investigations was 0.276 g/g cat...

  4. The stability of CaS in circulating fluidized bed boiler residue and the possible release of H2S gas to the atmosphere

    International Nuclear Information System (INIS)

    Mattisson, T.; Lyngfelt, A.

    1995-01-01

    During the combustion of coal, SO 2 is released to the atmosphere. Because of environmental concerns with acid rain, the capture of SO 2 is an important issue. In fluidized bed combustion SO 2 is captured in-situ by limestone or dolomite to form CaSO 4 . This product is stable and can be disposed of or reused as gypsum. In order to capture the sulphur as CaSO 4 oxidizing conditions are necessary. In a fluidized bed boiler (FBB) CaS may form in regions with reducing conditions, and FBB ashes sampled under irregular operating conditions may contain as much as 50 % of the captured sulphur as CaS. The stability of CaS in a landfill environment is thus very important. It is possible that the sulphide decomposes in the presence of moisture or runoff leachate with the subsequent release of H 2 S gas. This re-release of captured sulphur could have a substantial effect on the overall sulphur capture efficiency, with more sulphur released to the atmosphere than previously thought. In this study the stability of CaS in bed ashes from a 12 MW circulating FBB combusting coal has been investigated, with focus on the release of H 2 S gas. (orig.)

  5. Highly efficient direct Z-scheme WO3/CdS-diethylenetriamine photocatalyst and its enhanced photocatalytic H2 evolution under visible light irradiation

    Science.gov (United States)

    Hu, Taiping; Li, Pengfei; Zhang, Jinfeng; Liang, Changhao; Dai, Kai

    2018-06-01

    Cadmium sulfide (CdS) has demonstrated great promise in artificial photocataytic hydrogen (H2) production. However, the serious photocorrosion hinders its effective interaction and real-life application. In this work, a typical direct Z-scheme WO3/CdS-diethylenetriamine (CdS-DETA) composite has been designed via facile in-situ solvothermal method, which exhibits excellent H2 production properties in visible light region. In this system, the inorganic-organic CdS-DETA nanobelts (NBs) possess enough active sites and large surface area for the encouraging nanojunction structure information. Furthermore, we also systematically calculated energy band structure and investigated charge transfer of the WO3/CdS-DETA by PL and photocurrent test, the results demonstrated that the suitable band gap matching between CdS-DETA and WO3 and high redox potential improve the separation of photogenerated holes and electrons, restraining intrinsic photocorrosion of CdS as well as improving the photocatalytic activity. 5%WO3/CdS-DETA presented the most outstanding H2 evolution rate (15522 μmol g-1 h-1), which is twice higher than that of pure CdS-DETA. WO3/CdS-DETA composites also presented high stability after three recycle H2 production experiment. Finally, direct Z-scheme photocatalytic mechanism is calculated.

  6. Anti-Ageing Effects of Sonchus oleraceus L. (pūhā Leaf Extracts on H2O2-Induced Cell Senescence

    Directory of Open Access Journals (Sweden)

    Zong-Quan Ou

    2015-03-01

    Full Text Available Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H2O2-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H2O2. Cells were treated with S. oleraceus extracts before or after H2O2 stress. The senescence- associated β-galactosidase (SA-β-gal activity was used to indicate cell senescence. S. oleraceus extracts showed higher cellular antioxidant activity than chlorogenic acid in WI-38 cells. S. oleraceus extracts suppressed H2O2 stress-induced premature senescence in a concentration-dependent manner. At 5 and 20 mg/mL, S. oleraceus extracts showed better or equivalent effects of reducing stress-induced premature senescence than the corresponding ascorbic acid treatments. These findings indicate the potential of S. oleraceus extracts to be formulated as an anti-ageing agent.

  7. Generation of MoS{sub 2} quantum dots by laser ablation of MoS{sub 2} particles in suspension and their photocatalytic activity for H{sub 2} generation

    Energy Technology Data Exchange (ETDEWEB)

    Baldoví, Herme G.; Latorre-Sánchez, Marcos; Esteve-Adell, Iván [Universitat Politècnica de València, Instituto Universitario de Tecnología Química CSIC-UPV and Departamento de Química (Spain); Khan, Anish; Asiri, Abdullah M. [King Abdulaziz University, Center of Excellence for Advanced Materials Research (Saudi Arabia); Kosa, Samia A. [King Abdulaziz University, Chemistry Department, Faculty of Science (Saudi Arabia); Garcia, Hermenegildo, E-mail: hgarcia@qim.upv.es [Universitat Politècnica de València, Instituto Universitario de Tecnología Química CSIC-UPV and Departamento de Química (Spain)

    2016-08-15

    MoS{sub 2} quantum dots (QDs) have been obtained in colloidal suspensions by 532 nm laser ablation (7 ns fwhp/pulse, 50 mJ/pulse) of commercial MoS{sub 2} particles in acetonitrile. High-resolution transmission electron microscopy images show a lateral size distribution from 5 to 20 nm, but a more homogeneous particle size of 20 nm can be obtained by silica gel chromatography purification in acetonitrile. MoS{sub 2} QDs obtained by laser ablation are constituted by 3–6 MoS{sub 2} layers (1.8–4 nm thickness) and exhibit photoluminescence whose λ{sub PL} varies from 430 to 530 nm depending on the excitation wavelength. As predicted by theory, the confinement effect and the larger periphery in MoS{sub 2} QDs increasing the bandgap and having catalytically active edges are reflected in an enhancement of the photocatalytic activity for H{sub 2} generation upon UV–Vis irradiation using CH{sub 3}OH as sacrificial electron donor due to the increase in the reduction potential of conduction band electrons and the electron transfer kinetics.

  8. New approach for risk based inspection of H2S based Process Plants

    International Nuclear Information System (INIS)

    Vinod, Gopika; Sharma, Pavan K.; Santosh, T.V.; Hari Prasad, M.; Vaze, K.K.

    2014-01-01

    Highlights: • Study looks into improving the consequence evaluation in risk based inspection. • Ways to revise the quantity factors used in qualitative approach. • New approach based on computational fluid dynamics along with probit mathematics. • Demonstrated this methodology along with a suitable case study for the said issue. - Abstract: Recent trend in risk informed and risk based approaches in life management issues have certainly put the focus on developing estimation methods for real risk. Idea of employing risk as an optimising measure for in-service inspection, termed as risk based inspection, was accepted in principle from late 80s. While applying risk based inspection, consequence of failure from each component needs to be assessed. Consequence evaluation in a Process Plant is a crucial task. It may be noted that, in general, the number of components to be considered for life management is very large and hence the consequence evaluation resulting from their failures (individually) is a laborious task. Screening of critical components is usually carried out using simplified qualitative approach, which primarily uses influence factors for categorisation. This necessitates logical formulation of influence factors and their ranges with a suitable technical basis for acceptance from regulators. This paper describes application of risk based inspection for H 2 S based Process Plant along with the approach devised for handling the influence factor related to the quantity of H 2 S released

  9. Silver nanoparticles reduce brain inflammation and related neurotoxicity through induction of H2S-synthesizing enzymes

    Science.gov (United States)

    Gonzalez-Carter, Daniel A.; Leo, Bey Fen; Ruenraroengsak, Pakatip; Chen, Shu; Goode, Angela E.; Theodorou, Ioannis G.; Chung, Kian Fan; Carzaniga, Raffaella; Shaffer, Milo S. P.; Dexter, David T.; Ryan, Mary P.; Porter, Alexandra E.

    2017-03-01

    Silver nanoparticles (AgNP) are known to penetrate into the brain and cause neuronal death. However, there is a paucity in studies examining the effect of AgNP on the resident immune cells of the brain, microglia. Given microglia are implicated in neurodegenerative disorders such as Parkinson’s disease (PD), it is important to examine how AgNPs affect microglial inflammation to fully assess AgNP neurotoxicity. In addition, understanding AgNP processing by microglia will allow better prediction of their long term bioreactivity. In the present study, the in vitro uptake and intracellular transformation of citrate-capped AgNPs by microglia, as well as their effects on microglial inflammation and related neurotoxicity were examined. Analytical microscopy demonstrated internalization and dissolution of AgNPs within microglia and formation of non-reactive silver sulphide (Ag2S) on the surface of AgNPs. Furthermore, AgNP-treatment up-regulated microglial expression of the hydrogen sulphide (H2S)-synthesizing enzyme cystathionine-γ-lyase (CSE). In addition, AgNPs showed significant anti-inflammatory effects, reducing lipopolysaccharide (LPS)-stimulated ROS, nitric oxide and TNFα production, which translated into reduced microglial toxicity towards dopaminergic neurons. Hence, the present results indicate that intracellular Ag2S formation, resulting from CSE-mediated H2S production in microglia, sequesters Ag+ ions released from AgNPs, significantly limiting their toxicity, concomitantly reducing microglial inflammation and related neurotoxicity.

  10. Facile preparation and improved photocatalytic H{sub 2}-production of Pt-decorated CdS/TiO{sub 2} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qi [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Xu, Jie [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, SA 5095 (Australia); Wang, Wenzhong, E-mail: wzwang@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Lu, Chunli [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2014-03-01

    Graphical abstract: - Highlights: • Pt-CdS/TiO{sub 2} nanorods were firstly realized by electrospinning. • They exhibited high photocatalytic H{sub 2} production activity. • The mechanism of the high performance was discussed. - Abstract: Pt-CdS/TiO{sub 2} nanorods with different molar ratios of Cd:Ti were prepared through an electrospinning method followed by sulfidation treatment and photodeposition. The nanorod-like samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence spectra (PL), and UV–vis diffuse reflectance spectroscopy (DRS). The results indicated that the as-prepared samples exhibited wider light absorption range and lower recombination rate of photogenerated electron–hole pairs after the introduction of Pt and CdS. The photocatalysis experiments showed that Pt-modified CdS/TiO{sub 2} nanorods exhibited much higher activities than pure TiO{sub 2} in the evolution of hydrogen under simulated solar light irradiation.

  11. Sensors based on mesoporous SnO{sub 2}-CuWO{sub 4} with high selective sensitivity to H{sub 2}S at low operating temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stanoiu, Adelina; Simion, Cristian E. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Calderon-Moreno, Jose Maria; Osiceanu, Petre [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania); Florea, Mihaela [University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, B-dul Regina Elisabeta 4-12, Bucharest (Romania); National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Teodorescu, Valentin S. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Somacescu, Simona, E-mail: somacescu.simona@gmail.com [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania)

    2017-06-05

    Highlights: • Mesoporous SnO{sub 2}-CuWO{sub 4} obtained by an inexpensive synthesis route. • Powders characterization performed by a variety of complementary techniques. • SnO{sub 2}-CuWO{sub 4} layers with high selective sensitivity to H{sub 2}S. • Low operating temperature and relative humidity influences. - Abstract: Development of new sensitive materials by different synthesis routes in order to emphasize the sensing properties for hazardous H{sub 2}S detection is one of a nowadays challenge in the field of gas sensors. In this study we obtained mesoporous SnO{sub 2}-CuWO{sub 4} with selective sensitivity to H{sub 2}S by an inexpensive synthesis route with low environmental pollution level, using tripropylamine (TPA) as template and polyvinylpyrrolidone (PVP) as dispersant/stabilizer. In order to bring insights about the intrinsic properties, the powders were characterized by means of a variety of complementary techniques such as: X-Ray Diffraction, XRD; Transmission Electron Microscopy, TEM; High Resolution TEM, HRTEM; Raman Spectroscopy, RS; Porosity Analysis by N{sub 2} adsorption/desorption, BET; Scanning Electron Microscopy, SEM and X-ray Photoelectron Spectroscopy, XPS. The sensors were fabricated by powders deposition via screen-printing technique onto planar commercial Al{sub 2}O{sub 3} substrates. The sensor signals towards H{sub 2}S exposure at low operating temperature (100 °C) reaches values from 10{sup 5} (for SnWCu600) to 10{sup 6} (for SnWCu800) over the full range of concentrations (5–30 ppm). The recovery processes were induced by a short temperature trigger of 500 °C. The selective sensitivity was underlined with respect to the H{sub 2}S, relative to other potential pollutants and relative humidity (10–70% RH).

  12. 2-(4-Methylphenyl-7-(2-methylpropoxy-4H-chromen-4-one–6-chloro-2-(4-methylphenyl-7-(2-methylpropoxy-4H-chromen-4-one (19/1

    Directory of Open Access Journals (Sweden)

    Vijay M. Barot

    2012-08-01

    Full Text Available The title co-crystal, 0.95C20H20O3·0.05C20H19ClO3, arises as the chloride carried over during the synthesis shares a position with an aromatic H atom; the partial occupancies are 0.947 (2 and 0.053 (2 for H and Cl, respectively. The molecular structure is stabilized by intramolecular C—H...O contacts, forming pseudo five- and six-membered rings with S(5 and S(6 graph-set motifs, respectively. The crystal structure features π–π stacking interactions between the centroids of the central fused ring systems [centroid–centroid distance = 3.501 (2 Å].

  13. Dopant-assisted negative photoionization Ion mobility spectrometry coupled with on-line cooling inlet for real-time monitoring H2S concentration in sewer gas.

    Science.gov (United States)

    Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Hua, Lei; Li, Haiyang

    2016-06-01

    Malodorous hydrogen sulfide (H2S) gas often exists in the sewer system and associates with the problems of releasing the dangerous odor to the atmosphere and causing sewer pipe to be corroded. A simple method is in demand for real-time measuring H2S level in the sewer gas. In this paper, an innovated method based on dopant-assisted negative photoionization ion mobility spectrometry (DANP-IMS) with on-line semiconductor cooling inlet was put forward and successfully applied for the real-time measurement of H2S in sewer gas. The influence of moisture was effectively reduced via an on-line cooling method and a non-equilibrium dilution with drift gas. The limits of quantitation for the H2S in ≥60% relative humidity air could be obtained at ≤79.0ng L(-1) with linear ranges of 129-2064ng L(-1). The H2S concentration in a sewer manhole was successfully determined while its product ions were identified by an ion-mobility time-of-fight mass spectrometry. Finally, the correlation between sewer H2S concentration and the daily routines and habits of residents was investigated through hourly or real-time monitoring the variation of sewer H2S in manholes, indicating the power of this DANP-IMS method in assessing the H2S concentration in sewer system. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. CdO Doped Indium Oxide Thick Film as a Low Temperature H2S Gas Sensor

    Directory of Open Access Journals (Sweden)

    D. N. CHAVAN

    2011-06-01

    Full Text Available The thick films of AR grade In2O3 were prepared by standard screen-printing technique. The gas sensing performance of thick film was tested for various gases. It showed maximum gas response to ethanol vapor at 350 oC for 80 ppm. To improve the gas response and selectivity of the film towards a particular gas, In2O3 thick films were modified by dipping them in an aqueous solution of 0.1 M CdCl2 for different intervals of time. The surface modified (10 min In2O3 thick film showed maximum response to H2S gas (10 ppm than pure In2O3 thick film at 150 oC. Cadmium oxide on the surface of the film shifts the gas response from ethanol vapor to H2S gas. A systematic study of sensing performance of the thick films indicates the key role played by cadmium oxide on the surface of thick films. The selectivity, gas response and recovery time of the thick films were measured and presented.

  15. 2,2-Dimethyl-2,3-dihydro-1H-perimidine

    Directory of Open Access Journals (Sweden)

    Sarah Maloney

    2013-02-01

    Full Text Available The title compound, C13H14N2, was obtained from reaction of diaminonaphthalene with acetone. In both independent molecules in the asymmetric unit, the tricyclic perimidine consists of a planar (r.m.s. deviations = 0.0125 and 0.0181 Å naphthalene ring system and an envelope conformation C4N2 ringwith the NCN group hinged with respect to the naphthalene backbone by 36.9 (2 and 41.3 (2° in the two independent molecules. The methyl substituents are arranged approximately axial and equatorial on the apical C atom. In the crystal, one of the N—H groups of one independent molecule is involved in classical N—H...N hydrogen bonding. Short intermolecular (C/N—H...π(arene interactions, near the short T-shaped limit, link molecules in the absence of strong acceptors.

  16. H2S Sensing by Hybrids Based on Nanocrystalline SnO2 Functionalized with Cu(II Organometallic Complexes: The Role of the Ligand Platform

    Directory of Open Access Journals (Sweden)

    Marina Rumyantseva

    2017-11-01

    Full Text Available This paper deals with the functionalization of nanocrystalline SnO2 with Cu(II complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO2 hybrid material complexes of Cu(II with phthalocyanine, porphyrinines, bipyridine and azadithiacrown etherwere used. The analysis of gas sensor properties showed the possibility of increasing the sensitivity and selectivity of hybrid materials in H2S detection due to the electron transfer from SnO2 to an adsorbed organic molecule, which changes during the interaction between H2S and Cu(II ions.

  17. Tail gas treatment of SEWGS technology. Literature review on CO2 and H2S separation

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, E.N.; Van Dijk, H.A.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2011-12-15

    This literature review is the result of an investigation of the most important way to remove sulphur for the last decades. We will discuss Claus and Claus tail gas process options to solve the problem. Next to solutions which come from membranes, direct oxidation catalysis, from acid gas removal technology, sorbent technology, and liquid oxidation. Each field will be described and explained to understand in which way it could be suitable to separate CO2 and H2S and reach our goals with regard to CO2 transport and storage conditions. Finally, the target of this work will be to propose some interesting and promising solutions in view of future experiments.

  18. Inhibition of H9N2 virus invasion into dendritic cells by the S-layer protein from L. acidophilus ATCC 4356

    Directory of Open Access Journals (Sweden)

    Xue Gao

    2016-10-01

    Full Text Available Probiotics are essential for the prevention of virus invasion and the maintenance of the immune balance. However, the mechanism of competition between probiotics and virus are unknown. The objectives of this study were to isolate the surface layer (S-layer protein from L. acidophilus ATCC 4356 as a new antiviral material, to evaluate the stimulatory effects of the S-layer protein on mouse dendritic cells (DCs and to verify its ability to inhibit the invasion of H9N2 avian influenza virus (AIV in DCs. We found that the S-layer protein induced DCs activation and up-regulated the IL-10 secretion. The invasion and replication of the H9N2 virus in mouse DCs was successfully demonstrated. However, the invasion of H9N2 virus into DCs could be inhibited by treatment with the S-layer protein prior to infection, which was verified by the reduced hemagglutinin (HA and neuraminidase (NA mRNA expression, and nucleoprotein (NP protein expression in the DCs. Furthermore, treatment with the S-layer protein increases the Mx1, Isg15, and Ddx58 mRNA expressions, and remits the inflammatory process to inhibit H9N2 AIV infection. In conclusion, the S-layer protein stimulates the activation of mouse DCs, inhibits H9N2 virus invasion of DCs, and stimulates the IFN-I signalling pathway. Thus, the S-layer protein from Lactobacillus is a promising biological antiviral material for AIV prevention.

  19. Reduction of H{sub 2} S during the mineral coal gasification by using dolomite addition in a fluidized bed reactor; Diminuicao de H{sub 2} S na gaseificacao de carvao mineral mediante adicao de dolomita em reator de leito fluidizado

    Energy Technology Data Exchange (ETDEWEB)

    Behanie, John Jairo Ramirez [Universidad Pontificia Bolivariana, Medellin (Colombia). Centro de Investigaciones para el Desarrollo Integral. Grupo de Investigaciones Ambientales]. E-mail: jbehaine@logos.upb.edu.co; Sanches, Caio Glauco [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia Termica e de Fluidos]. E-mail: caio@fem.unicamp.br

    2000-07-01

    Brazilian mineral coal from Candiota mine (Rio Grande do Sul State) was gasified with air in a atmospheric fluidized bed reactor at laboratory scale. Experimental essays carried out in a 0.2 m internal diameter reactor permitted both, to evaluate the gasifier operation at different air factors without dolomite particles addition, and to study the effect adsorbent on the capture hydrogen sulfide (H2 S), contained in the generated gas. Test were done with and without the use of dolomite. Without using dolomite, the maximum gas lower heating value was 2.2 MJ/N m3 and the cold gas thermal efficiency was close to 43%, operating at an air factor between 0.45 and 0.60. During the experimental test with dolomite , a maximum reduction of 58% for H2 S was attained using a molar ratio of Ca/S equal to 4. Literature review showed higher capture efficiencies, even at lower molar ratio (Ca/S). Variances were probably caused by low residence times in the gas-solid interaction, considering the used bubble fluidization regime. (author)

  20. Serotonin and dopamine protect from hypothermia/rewarming damage through the CBS/H2S pathway

    NARCIS (Netherlands)

    Talaei, Fatemeh; Bouma, Hjalmar; Van der Graaf, Adrianus; Strijkstra, Arjen; Schmidt, Martina; Henning, Robert

    2011-01-01

    Biogenic amines have been demonstrated to protect cells from apoptotic cell death. Herein we show for the first time that serotonin and dopamine increase H2S production by the endogenous enzyme cystathionine-beta-synthase (CBS) and protect cells against hypothermia/rewarming induced reactive oxygen

  1. Utilização de linhagens diplóides uvsH//uvsH de Aspergillus nidulans (Ascomycetes para a avaliação do potencial recombinagênico de agentes químicos e físicos uvsH//uvsH diploid strain favors an efficient method to evaluate the recombinagenic effect of chemical and physical agents in Aspergillus nidulans (Ascomycetes

    Directory of Open Access Journals (Sweden)

    Francielle Baptista

    2001-05-01

    Full Text Available O ascomiceto Aspergillus nidulans apresenta-se como um excelente sistema para o estudo da recombinação somática, por passar grande parte de seu ciclo celular em G2 e por apresentar mutações uvs que promovem aumento das freqüências normais de recombinação mitótica (uvsF e uvsH. O presente trabalho teve como objetivo obter uma nova linhagem diplóide de A. nidulans, com características apropriadas para estudos da recombinagênese, tais como: hetererozigose para marcadores nutricionais e de coloração de conidios e homozigose para a mutação uvsH. A maior sensibilidade do diplóide uvsH//uvsH no monitoramento de eventos de recombinação mitótica foi demonstrada através dos mais altos índices de recombinação mitótica espontânea por ele apresentados, em comparação com o diplóide uvsH+//uvsH +. A nova linhagem apresenta-se como uma ferramenta versátil, podendo ser utilizada em diferentes estudos relacionados à recombinação mitótica em A. nidulansAscomycete Aspergillus nidulans is an excellent system for mitotic crossing-over studies. This is due to the fact that much of its cell cycle is passed in G2 and presents uvs mutations that increase frequencies of normal mitotic recombinations (uvsF and uvsH. The aim of this research was to obtain a new diploid strain of A. nidulans with proper characteristics for recombinagenesis investigations, or rather, heterozygous for nutritional markers and conidia coloration and homozygous for uvsH mutation. Higher sensitivity of diploid uvsH//uvsH in the monitoring of mitotic recombination events was shown by higher indexes of the diploid’s spontaneous mitotic recombination when compared with diploid uvsH+//uvsH +. New strain is a versatile tool that may be used in different studies on mitotic recombination in A. nidulans

  2. Nature of the three-electron bond in H2S∴SH2+

    NARCIS (Netherlands)

    Bickelhaupt, F. Matthias; Diefenbach, Axel; De Visser, Sam P.; De Koning, Leo J.; Nibbering, Nico M.M.

    1998-01-01

    We have investigated the model system H2S∴-SH2+, i.e., the sulfur-sulfur bound dimer radical cation of H2S, using both density functional theory (LDA, BP86, PW91) and traditional ab initio theory (up to CCSD-(T)). Our purpose is to better understand the nature of the three-electron bond. The S-S

  3. Experimental studies of collisions of excited Li(4p) atoms with C2H4, C2H6, C3H8 and theoretical interpretation of the Li-C2H4 system

    International Nuclear Information System (INIS)

    Semmineh, Natenael; Bililign, Solomon; Hagebaum-Reignier, Denis; Jeung, Gwang-Hi

    2009-01-01

    Collisions of excited Li(4p) states with C 2 H 4 , C 2 H 6 and C 3 H 8 are studied experimentally using far-wing scattering state spectroscopy techniques. High-level ab initio quantum mechanical studies of the Li-C 2 H 4 system are conducted to explain the results of the experiment for this system. The recent and present works indicate that knowledge of the internal structure of the perturber (C 2 H 4 , C 2 H 6 and C 3 H 8 ) is essential to fully understand the interaction between the metal and the hydrocarbon molecules. The ab initio calculation shows that the Li(4d) (with little probability under the experimental conditions) and the Li(4p) can be formed directly through the laser pumping. It also shows that the Li(4s) and Li(3d) states can be formed through an electronic diabatic coupling involving a radiationless process. However, the Li(3p), Li(3s) and Li(2p) states can only be formed through a secondary diabatic coupling which is a much less probable process than the primary one. The calculation limited to two C 2v sections of the potential energy surfaces (PESs) shows peculiar multi-state crossings that we have never seen in other lithium complexes we studied

  4. Electrodos híbridos a base de Polianilina/V2O5 para el desarrollo de baterías plásticas de litio

    Directory of Open Access Journals (Sweden)

    Gómez-Romero, P.

    2000-06-01

    Full Text Available We present the synthesis and characterization of the hybrid PAni/V2O5 and its performance as cathode in reversible lithium cells. The synthesis was made directly from the V2O5 gel. We observe a direct relationship between the synthesis conditions and the specific charge (Ah/Kg obtained during the analysis of the material as cathode in lithium batteries. On the other hand, oxygen treatments were carried out to increase the oxidation state of the V2O5 in the hybrid material. Higher temperatures and period of treatment leads to the decomposition of the organic part of the hybrid PAni/V2O5. The syntesis conditions of the hybrid, showed great influence over the specific charge. Values as high as 302 Ah/Kg were observed at slow discharge rate (C/48 and 200-238 Ah/Kg at discharge rate of C/12, this values correspond to the insertion of 2.7 and 2.08 lithium ions respectively. These values demonstrate the synergic response between PAni and the V2O5 oxide material.Presentamos la síntesis y caracterización del híbrido PAni/V2O5 y su aplicación como cátodo en baterías reversibles de litio. La síntesis se realizó directamente a partir del hidrogel de V2O5. Observamos una relación directa entre las condiciones de síntesis y la carga específica (Ah/Kg obtenida durante el análisis del material como cátodo en baterías recargables de litio. Por otro lado, se llevaron a cabo tratamientos con oxígeno para aumentar el estado de oxidación del V2O5 en el material híbrido. El uso de mayores temperaturas y tiempos de reacción provoca la descomposición de la parte orgánica del híbrido PAni/V2O5. La carga específica y tratamientos posteriores de los híbridos obtenidos son muy sensibles a las condiciones de síntesis. Se observaron valores tan elevados como 302 Ah/Kg a baja velocidad de descarga (C/48 y 200-238 Ah/Kg a una velocidad de descarga de C/12, valores que corresponden a la inserción de 2.7 y 2.08 iones litio respectivamente. Estos valores

  5. Relación entre daño mitocondrial y producción de H2O2 en embriones bovinos producidos in vitro con alto y bajo potencial de desarrollo

    Directory of Open Access Journals (Sweden)

    Marlene Jiménez

    2001-04-01

    Full Text Available

    Los embriones producidos in vitro (EPIV presentan bloqueo en el
    desarrollo en el momento de la activación del genoma (8-16 células en bovinos, limitando la producción de blastocitos (35%. Este fenómeno ha sido relacionado con la producción de Especies Reactivas de Oxígeno (ERO. Entre las fuentes de ERO se han descrito altas tensiones de oxígeno, exposición a la luz y alteración del metabolismo oxidativo (1. Los EPIV con baja competencia para superar el bloqueo presentan fallas en la funcionalidad mitocondrial (1 y nucleolar, exhibiendo un retardo en su tasa de clivaje (2. Algunos autores han relacionado el tiempo al primer clivaje con la cantidad relativa de ciertos
    transcriptos, como Glutatión (2, un limpiador de ERO, sugiriendo que los embriones incompetentes presentan fallas  transcripcionales que les impiden defenderse contra las ERO producidas en cultivo, quizás manteniendo niveles elevados de H2O2 lo que los hace más susceptibles al daño celular.
    Hasta el presente no se ha efectuado un estudio de cinética de producción de ERO, en EPIV bovinos con alta y baja competencia durante el desarrollo temprano, ni se ha logrado esclarecer el papel de la mitocondria en la generación de ERO (como fuente o como blanco.
    Los objetivos de este estudio son determinar la cinética de producción de H2O2 en embriones con alta y baja competencia para superar el bloqueo y la relación de éstos con procesos de daño mitocondrial y mortalidad embrionaria.

     

     

  6. Investigation of the Na2(H2PO2)2 - Ba(H2PO2)2 - H2O Water-Salt Ternary System at Room Temperature

    OpenAIRE

    Erge, Hasan; Turan, Hakan; Kul, Ali Riza

    2016-01-01

    Objective: In this study, the solubility, density, conductivity and phase equilibria of the Na2(H2PO2)2-Ba(H2PO2)2-H2O ternary system located in the structure of the Na+, Ba2+, (H2PO2)-//H2O quaternary reciprocal water-salt system were investigated using physicochemical analysis methods. Material and Methods: Riedel-de Haen and Merck salts were used to investigate the solubility and phase equilibria of the Na2(H2PO2)2 -Ba(H2PO2)2-H2O ternary water–salt system at room temperature Res...

  7. [(4S,5S-2,2-Dimethyl-1,3-dioxolane-4,5-diyl]bis[N-(thiophen-2-ylmethylidenemethanamine

    Directory of Open Access Journals (Sweden)

    Yan Jiang

    2012-02-01

    Full Text Available In the title compound, C17H20N2O2S2, the five-membered heterocycle exhibits an envelope conformation and the molecular chirality and configuration are well preserved from l-tartaric acid. The dihedral angle between the two thiophene rings is 17.0 (2°. In the crystal, molecules are linked by C—H...O and C—H...S hydrogen interactions, which are effective in the stabilization of the crystal structure.

  8. H2O sources in regions of star formation

    International Nuclear Information System (INIS)

    Lo, K.Y.; Burke, B.F.; Haschick, A.D.

    1975-01-01

    Regions and objects believed to be in early stages of stellar formation have been searched for H 2 O 22-GHz line emission with the Haystack 120-foot (37 m) telescope. The objects include radio condensations, infrared objects in H ii regions, and Herbig-Haro objects. Nine new H 2 O sources were detected in the vicinity of such objects, including the Sharpless H ii regions S152, S235, S255, S269, G45.1+0.1, G45.5+0.1, AFCRL infrared object No. 809--2992, and Herbig-Haro objects 1 and 9. The new H 2 O sources detected in H ii regions are associated, but not coincident, with the the radio condensations. Water vapor line emission was detected in approx.25 percent of the regions searched. The association of H 2 O sources with regions of star formation is taken to be real. The spatial relationship of H 2 O sources to infrared objects, radio condensations, class I OH sources, and molecular clouds are discussed. The suggestion is made that an H 2 O source may be excited by a highly obscured star of extreme youth

  9. Adsorption of H{sub 2}S or SO{sub 2} on an activated carbon cloth modified by ammonia treatment

    Energy Technology Data Exchange (ETDEWEB)

    Boudou, J.P.; Chehimi, M.; Broniek, E.; Siemieniewska, T.; Bimer, J. [University of Paris, Paris (France)

    2003-07-01

    The aim of this research is to investigate how ammonia treatment of the surface can influence the activity of a viscose-based activated carbon cloth (ACC) for the oxidative retention of H{sub 2}S and SO{sub 2} in humid air at 25{sup o}C. Surface basic nitrogen groups were introduced either by treatment with ammonia/air at 300{sup o}C or with ammonia/steam at 800{sup o}C. The pore structure of the samples so prepared was examined by adsorption measurements. Changes in the surface chemistry were assessed by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and temperature programmed desorption (TPD). The change of ACC activity could not be merely attributed to surface nitrogen groups but to other changes in the support. Ammonia/steam treatment improved ACC performance the most, not only by introducing nitrogen surface groups, but also by extending the microporosity and by modifying the distribution of surface oxygen groups. Successive adsorption-regeneration cycles showed important differences between oxidative retention of H{sub 2}S and SO{sub 2} and the subsequent catalyst/support regeneration process.

  10. Coordination polymers of scandium sulfate. Crystal structures of (H2Bipy)[Sc(H2O)(SO4)2]2·2H2O and (H2Bipy)[HSO4]2

    International Nuclear Information System (INIS)

    Petrosyants, S.P.; Ilyukhin, A.B.

    2005-01-01

    Compounds with general formula Cat x [Sc(H 2 O) z (SO 4 ) y ]·nH 2 O (Cat=NH 4 , H 2 Bipy (Bipy - 4,4'-bipyridine), HEdp (Edp - ethylene dipyridine)) identified on element analysis data and IR spectra are synthesized. X-ray diffraction analysis of (H 2 Bipy)[Sc(H 2 O)(SO 4 ) 2 ] 2 ·2H 2 O shows that in structure of the compound chains of ScO 6 octahedron and SO 4 tetrahedrons are joined in bands by tridentate coordination of sulfate ions. Bands form skeleton in endless emptiness of which there are H 2 Bipy 2+ cations [ru

  11. 2-(2-Hydroxy-3-methoxyphenyl-1H-benzimidazol-3-ium perchlorate

    Directory of Open Access Journals (Sweden)

    Chuan Chen

    2012-06-01

    Full Text Available In the title molecular salt, C14H13N2O2+·ClO4−, the ring systems in the cation are almost coplanar [dihedral angle = 5.53 (13°]. Intramolecular N—H...O and O—H...O hydrogen bonds generate S(6 and S(5 rings, respectively. In the crystal, the two H atoms involved in the intramolecular hydrogen bonds also participate in intermolecular links to acceptor O atoms of the perchlorate anions. A simple intermolecular N—H...O bond also occurs. Together, these form a double-chain structure along [101].

  12. Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H2O2 and Na2S2O8 under UV-254 nm irradiation

    International Nuclear Information System (INIS)

    He, Xuexiang; Mezyk, Stephen P.; Michael, Irene; Fatta-Kassinos, Despo; Dionysiou, Dionysios D.

    2014-01-01

    Graphical abstract: - Highlights: • Removal efficiency was comparable at different UV fluence rates but same fluence. • Reducing pH to 3 or 2 did not inhibit the removal of nitrobenzene by UV/S 2 O 8 2− . • 1.84 × 10 −14 M [HO • ] ss and 3.10 × 10 −13 M [SO 4 • − ] ss in UV/S 2 O 8 2− were estimated. • HO • reacted faster with the β-lactams than SO 4 • − but sharing similar byproducts. • Transformation pathways included hydroxylation, hydrolysis and decarboxylation. - Abstract: The extensive production and usage of antibiotics have led to an increasing occurrence of antibiotic residuals in various aquatic compartments, presenting a significant threat to both ecosystem and human health. This study investigated the degradation of selected β-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254 nm activated H 2 O 2 and S 2 O 8 2− photochemical processes. The UV irradiation alone resulted in various degrees of direct photolysis of the antibiotics; while the addition of the oxidants improved significantly the removal efficiency. The steady-state radical concentrations were estimated, revealing a non-negligible contribution of hydroxyl radicals in the UV/S 2 O 8 2− system. Mineralization of the β-lactams could be achieved at high UV fluence, with a slow formation of SO 4 2− and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16 Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18 Da) at the β-lactam ring and decarboxylation (–44 Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H 2 O 2 and UV/S 2 O 8 2− advanced oxidation processes (AOPs) are capable of degrading β-lactam antibiotics decreasing consequently the antibiotic activity of treated waters

  13. A [Mo{sub 2}O{sub 2}S{sub 2}]-based ring system incorporating tartrate as the bridging ligand. Synthesis, structure and catalytic activity of Cs{sub 4}[Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sub 2}(μ{sub 4}-tart){sub 2} (tart=[C{sub 4}H{sub 2}O{sub 6}]{sup 4-})

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Ting-Ting; Cui, Yu-Jie; Xin, Zhifeng; Jia, Ai-Quan; Zhang, Qian-Feng [Anhui Univ. of Technology, Anhui (China). Inst. of Molecular Engineering and Applied Chemistry and Anhui Province Key Lab. of Metallurgy Engineering and Resources Recycling

    2017-08-01

    Treatment of [Mo{sub 2}S{sub 2}O{sub 2}(H{sub 2}O){sub 6}]{sup 2+} with racemic tartaric acid (tartH{sub 4}) in the presence of sodium hydroxide and cesium chloride in aqueous solution led to the isolation of a new tetra-molybdenum ring cluster Cs{sub 4}[Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sub 2}(μ{sub 4}-tart){sub 2}. The cyclic cluster polyanion consists of two dinuclear [Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sup 2+} moieties and two bridging tart{sup 4-} ligands. The cyclic polyoxothiomolybdate cluster, supported on the mesoporous silica SBA-15, was tested for heterogenerous catalysis in thiophene hydrodesulfurization.

  14. S-wave elastic scattering of ${\\it o} $-Ps from $\\text {H} _2 $ at low energy

    KAUST Repository

    Zhang, J. -Y.

    2018-03-08

    The confined variational method is applied to investigate the low-energy elastic scattering of ortho-positronium from $\\\\text{H}_2$ by first-principles quantum mechanics. Describing the correlation effect with explicitly correlated Gaussians, we obtain accurate $S$-wave phase shifts and pick-off annihilation parameters for different incident momenta. By a least-squares fit of the data to the effective-range theory, we determine the $S$-wave scattering length, $A_s=2.06a_0$, and the zero-energy value of the pick-off annihilation parameter, $^1\\\\!\\\\text{Z}_\\\\text{eff}=0.1858$. The obtained $^1\\\\!\\\\text{Z}_\\\\text{eff}$ agrees well with the precise experimental value of $0.186(1)$ (J.\\\\ Phys.\\\\ B \\\\textbf{16}, 4065 (1983)) and the obtained $A_s$ agrees well with the value of $2.1(2)a_0$ estimated from the average experimental momentum-transfer cross section for Ps energy below 0.3 eV (J.\\\\ Phys.\\\\ B \\\\textbf{36}, 4191 (2003)).

  15. New lanthanide hydrogen phosphites LnH (P03H)2 2H20

    International Nuclear Information System (INIS)

    Durand, J.; Tijani, N.; Cot, L.; Loukili, M.; Rafiq, M.

    1988-01-01

    LnH ((P0 3 H) 2 2H 2 0 is prepared from lanthanide oxide and phosphorous acid with Ln = La, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er or Tm. By thermal gravimetric analysis LnH (P0 3 H) 2 and LnH 2 P 2 0 5 (P0 3 H) 2 are obtained. The three salts are orthorhombic. Parameters and space groups are given for the three salts of each lanthanide. 4 tabs., 13 refs

  16. {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions at sub-coulomb energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Sparta, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L. [Universita degli Studi di Enna Kore, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Cyclotron Institute Texas A and M University - College Station, Texas (United States); Excellence Cluster Universe - Technische Universitaet Muenchen, Garching, Germany and GSI Helmholtzzentrum fuer Schwerionenforschung GmbH - Theorie Darmstadt (Germany); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); School of Physics and Astronomy - University of Edinburgh, SUPA (United Kingdom); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy)

    2012-11-20

    The {sup 2}H({sup 3}He,p{sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n{sup 3}He){sup 1}H processes have been measured in quasi free kinematics to investigate for the first time the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions by means of the Trojan Horse Method. The {sup 3}He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4{+-}1.8 MeVb for {sup 3}H+p and 60.1{+-}1.9 MeVb for {sup 3}He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

  17. Effect of moisture control and air venting on H2S production and leachate quality in mature C&D debris landfills.

    Science.gov (United States)

    Zhang, Jianye; Dubey, Brajesh; Townsend, Timothy

    2014-10-21

    The effect of air venting and moisture variation on H2S production and the leaching of metals/metalloids (arsenic, copper, chromium, and boron) from treated wood in aged mature construction and demolition (C&D) debris landfills were examined. Three simulated C&D debris landfill lysimeters were constructed and monitored, each containing as a major debris component either wooden pallets, chromated copper arsenate (CCA) treated wood, or alkaline copper quaternary (ACQ) treated wood. The lysimeters were operated with alternating periods of water addition (a total of 160 L in four equal amounts) and air venting (68.4 m(3)per day for 121 days in two phases). Moisture addition did not increase H2S levels in the long term, and a significant drop in H2S concentration was observed (up to 99%) when aerobic conditions were promoted through air venting. H2S concentrations increased after venting stopped up to values approximately two orders of magnitude lower than observed prior to venting. Venting had the immediate consequence of suppressing biological H2S production, and the longer-term effect of decreasing organic matter that could otherwise be utilized in this process. Under aerobic conditions, the levels of arsenic, chromium, and boron in leachate decreased up to 96%, 49%, and 68%, respectively, while copper was found to increase up to 200% in CCA and 445% in ACQ column leachates.

  18. Anti-Ageing Effects of Sonchus oleraceus L. (pūhā) Leaf Extracts on H2O2-Induced Cell Senescence

    OpenAIRE

    Zong-Quan Ou; Thomas Rades; Arlene McDowell

    2015-01-01

    Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae) leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H2O2-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H2O2. Cells were treated with S. oleraceus extracts before or after H2O2 stress...

  19. Crystal structure of (1S,2S,2′R,3a′S,5R-2′-[(5-bromo-1H-indol-3-ylmethyl]-2-isopropyl-5,5′-dimethyldihydro-2H-spiro[cyclohexane-1,6′-imidazo[1,5-b]isoxazol]-4′(5′H-one

    Directory of Open Access Journals (Sweden)

    Siwar Ghannay

    2016-08-01

    Full Text Available In the title compound, C24H32BrN3O2, the six-membered cyclohexane ring adopts a chair conformation and the isoxasolidine ring adopts a twisted conformation. The molecule has five chiral centres and the absolute configuration has been determined in this analysis. The molecular structure is stabilized by weak intramolecular C—H...O and C—H...N contacts. In the crystal, molecules are linked by N—H...N and C—H...O hydrogen bonds, forming undulating sheets parallel to the bc plane.

  20. Effects of V-shaped edge defect and H-saturation on spin-dependent electronic transport of zigzag MoS2 nanoribbons

    International Nuclear Information System (INIS)

    Li, Xin-Mei; Long, Meng-Qiu; Cui, Li-Ling; Xiao, Jin; Zhang, Xiao-Jiao; Zhang, Dan; Xu, Hui

    2014-01-01

    Based on nonequilibrium Green's function in combination with density functional theory calculations, the spin-dependent electronic transport properties of one-dimensional zigzag molybdenum disulfide (MoS 2 ) nanoribbons with V-shaped defect and H-saturation on the edges have been studied. Our results show that the spin-polarized transport properties can be found in all the considered zigzag MoS 2 nanoribbons systems. The edge defects, especially the V-shaped defect on the Mo edge, and H-saturation on the edges can suppress the electronic transport of the systems. Also, the spin-filtering and negative differential resistance behaviors can be observed obviously. The mechanisms are proposed for these phenomena. - Highlights: • The spin-dependent electronic transport of zigzag MoS 2 nanoribbons. • The effects of V-shaped edge defect and H-saturation. • The effects of spin-filter and negative differential resistance can be observed