WorldWideScience

Sample records for hydrogen ordering influence

  1. Ordered pairing in liquid metallic hydrogen

    Science.gov (United States)

    Carlsson, A. E.; Ashcroft, N. W.

    1983-01-01

    We study two possible types of pairing involving the protons of a proposed low-temperature liquid phase metallic hydrogen. Electron-proton pairing, which can result in an insulating phase, is investigated by using an approximate solution of an Eliashberg-type equation for the anomalous self-energy. A very low estimate of the transition temperature is obtained by including proton correlations in the effective interaction. For proton-proton pairing, we derive a new proton pair potential based on the Abrikosov wave function. This potential includes the electron-proton interaction to all orders and has a much larger well depth than is obtained with linear screening methods. This suggests the possibility of either a superfluid paired phase analogous to that in He-3, or alternatively a phase with true molecular pairing.

  2. Electrochemical Hydrogen Storage in a Highly Ordered Mesoporous Carbon

    Directory of Open Access Journals (Sweden)

    Dan eLiu

    2014-10-01

    Full Text Available A highly order mesoporous carbon has been synthesized through a strongly acidic, aqueous cooperative assembly route. The structure and morphology of the carbon material were investigated using TEM, SEM and nitrogen adsorption-desorption isotherms. The carbon was proven to be meso-structural and consisted of graphitic micro-domain with larger interlayer space. AC impedance and electrochemical measurements reveal that the synthesized highly ordered mesoporous carbon exhibits a promoted electrochemical hydrogen insertion process and improved capacitance and hydrogen storage stability. The meso-structure and enlarged interlayer distance within the highly ordered mesoporous carbon are suggested as possible causes for the enhancement in hydrogen storage. Both hydrogen capacity in the carbon and mass diffusion within the matrix were improved.

  3. Influence of hydrogen on hydrogenated cadmium telluride optical spectra

    Energy Technology Data Exchange (ETDEWEB)

    Pociask, M.; Polit, J.; Sheregii, E.; Cebulski, J. [Institute of Physics, University of Rzeszow (Poland); Kisiel, A. [Institute of Physics, Jagiellonian University, Krakow (Poland); Mycielski, A. [Institute of Physics, PAS, Warszawa (Poland); Morgiel, J. [Polish Academy of Sciences, Institute of Metallurgy and Materials Sciences, Krakow (Poland); Piccinini, M. [INFN-Laboratori Nazionali di Frascati (Italy); Dipartimento Scienze Geologiche, Universita Roma Tre, Rome (Italy); Marcelli, A.; Robouch, B.; Guidi, M.C. [INFN-Laboratori Nazionali di Frascati (Italy); Savchyn, V. [Ivan Franko Lviv National University (Ukraine); Izhnin, I.I. [Institute for Materials SRC ' ' Carat' ' , Lviv (Ukraine); Zajdel, P. [Institute of Fizyki, University of Silesia, 4 Uniwersytecka Str., 40-007 Katowice (Poland); Nucara, A. [Universita' di Roma La Sapienza, P. le Aldo Moro 1, Rome (Italy)

    2009-09-15

    The presence of oxygen impurity in semiconducting materials affects the electrical properties of crystals and significantly limits their application. To remove oxygen impurity, ultra-pure hydrogen is used while growing Te-containing crystals such as CdTe, CdZnTe, and ZnTe. The hydrogenation of CdTe crystals is a technological process that purifies the basic material from oxygen, mainly cadmium and tellurium oxide compounds incorporated in CdTe crystalline lattice. In the present work we analyses the deformations induced by hydrogen and oxygen atoms in CdTe crystals looking at their influence on the near fundamental band (NFB), middle infrared (MIR) and far infrared (FIR) reflectivity spectra as well as on cathodoluminescence (CL) spectra. Comparison of the hydrogenated CdTe phonon structure profiles confirms the presence of hydrogen atoms bounded inside the lattice. The possible localization of hydrogen and oxygen ions within the tetrahedron coordinated lattice is discussed in the framework of a model that shows a good agreement with recent NFB, MIR and FIR experiments carried out on hydrogenated CdTe crystals. Measured reflection spectra in the wavelength range 190-1400 nm (NFB) indicate the appearance in CdTe(H{sub M}) and CdTe(H{sub L}) of additional maxima at 966 nm related to the electron transitions from level about 0.2 eV above the valence band. The CL spectra confirmed existence of this electron level. We present a possible H{sub 2} alignment similar to the single H model i.e., over the face (at about 0.38 Aa). For this model the angle from the central atom to the H atoms is equal to 64 which is also close to the bonding angle of CdH{sub 2} (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Ordered ground states of metallic hydrogen and deuterium

    Science.gov (United States)

    Ashcroft, N. W.

    1981-01-01

    The physical attributes of some of the more physically distinct ordered states of metallic hydrogen and metallic deuterium at T = 0 and nearby are discussed. The likelihood of superconductivity in both is considered with respect to the usual coupling via the density fluctuations of the ions.

  5. Hydrogen attack - Influence of hydrogen sulfide. [on carbon steel

    Science.gov (United States)

    Eliezer, D.; Nelson, H. G.

    1978-01-01

    An experimental study is conducted on 12.5-mm-thick SAE 1020 steel (plain carbon steel) plate to assess hydrogen attack at room temperature after specimen exposure at 525 C to hydrogen and a blend of hydrogen sulfide and hydrogen at a pressure of 3.5 MN/sq m for exposure times up to 240 hr. The results are discussed in terms of tensile properties, fissure formation, and surface scales. It is shown that hydrogen attack from a high-purity hydrogen environment is severe, with the formation of numerous methane fissures and bubbles along with a significant reduction in the room-temperature tensile yield and ultimate strengths. However, no hydrogen attack is observed in the hydrogen/hydrogen sulfide blend environment, i.e. no fissure or bubble formation occurred and the room-temperature tensile properties remained unchanged. It is suggested that the observed porous discontinuous scale of FeS acts as a barrier to hydrogen entry, thus reducing its effective equilibrium solubility in the iron lattice. Therefore, hydrogen attack should not occur in pressure-vessel steels used in many coal gasification processes.

  6. Hafnium - an optical hydrogen sensor spanning six orders in pressure

    NARCIS (Netherlands)

    Boelsma, C.; Bannenberg, L.J.; Van Setten, M. J.; Steinke, N.J.; van Well, A.A.; Dam, B.

    2017-01-01

    Hydrogen detection is essential for its implementation as an energy vector. So far, palladium is considered to be the most effective hydrogen sensing material. Here we show that palladium-capped hafnium thin films show a highly reproducible change in optical transmission in response to a hydrogen

  7. Hydrogenated Graphenes by Birch Reduction: Influence of Electron and Proton Sources on Hydrogenation Efficiency, Magnetism, and Electrochemistry.

    Science.gov (United States)

    Eng, Alex Yong Sheng; Sofer, Zdeněk; Huber, Štěpán; Bouša, Daniel; Maryško, Miroslav; Pumera, Martin

    2015-11-16

    Interest in chemical functionalisation of graphenes today is largely driven by associated changes to its physical and material properties. Functionalisation with hydrogen was employed to obtain hydrogenated graphenes (also termed graphane if fully hydrogenated), which exhibited properties including fluorescence, magnetism and a tuneable band gap. Although the classical Birch reduction has been employed for hydrogenation of graphite oxide, variation exists between the choice of alkali metals and alcohols/water as quenching agents. A systematic study of electron (Li, Na, K, Cs) and proton sources (tBuOH, iPrOH, MeOH, H2O) has been performed to identify optimal conditions. The proton source exerted a great influence on the resulting hydrogenation with water and out-performed alcohols, and the lowest carbon-to-hydrogen ratio was observed with sodium and water with composition of C1.4H1O0.3. Although ferromagnetism at room temperature correlates well with increasing hydrogen concentrations, small contributions from trace iron impurities cannot be completely eliminated. In contrast, hydrogenated graphenes exhibit a significant paramagnetic moment at low temperatures that has no correlation with impurities, and therefore, originates from the carbon system. This is in comparison to graphene, which is strongly diamagnetic, and concentrations of paramagnetic centres in hydrogenated graphenes are one order of magnitude larger than that in graphite. Nonetheless, hydrogenation over a particular level might also excessively disrupt intrinsic sp(2) conjugation, resulting in unintended reduction of electrochemical properties. This was observed with heterogeneous electron-transfer rates and it was postulated that hydrogenated graphenes should generally have high defect densities, but only moderately high hydrogenation, should they be employed as electrode materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. THE HYBRID COUMPOUNDS AND THE INFLUENCE OF HYDROGEN BONDING

    Directory of Open Access Journals (Sweden)

    F ALLOUCHE

    2014-12-01

    Full Text Available Organic–inorganic hybrid materials have received increasing attention in recent research particularly because of their ability to combine the specific properties of inorganic frameworks and the features of organic molecules, including the formation of weak interactions. These materials have recently attracted further interest due to their attractive potential for application as insulators in the electronics industry. They offer promising opportunities for the development of efficient conductors, ferroelectrics, and semiconductors in a wide range of electronic applications [1,2]. The hybrid compounds are rich in H-bonds and they could be used to this effect because of their potential importance in constructing sophisticated assemblies from discrete ionic or molecular building blocks due to its strength and directionality. In order to enrich the varieties in such kinds of hybrid materials and to investigate the influence of hydrogen bonds on the on the structural features, they have synthesized a new compound, This kind of hydrogen bonding appears in the active sites of several biological systems and is observed in similar previously studied hybrid compounds.

  9. Ordering of hydrogen bonds in high-pressure low-temperature H2O.

    Science.gov (United States)

    Cai, Y Q; Mao, H-K; Chow, P C; Tse, J S; Ma, Y; Patchkovskii, S; Shu, J F; Struzhkin, V; Hemley, R J; Ishii, H; Chen, C C; Jarrige, I; Chen, C T; Shieh, S R; Huang, E P; Kao, C C

    2005-01-21

    The near K-edge structure of oxygen in liquid water and ices III, II, and IX at 0.25 GPa and several low temperatures down to 4 K has been studied using inelastic x-ray scattering at 9884.7 eV with a total energy resolution of 305 and 175 meV. A marked decrease of the preedge intensity from the liquid phase and ice III to ices II and IX is attributed to ordering of the hydrogen bonds in the proton-ordered lattice of the latter phases. Density functional theory calculations including the influence of the Madelung potential of the ice IX crystal correctly account for the remaining preedge feature. Furthermore, we obtain spectroscopic evidence suggesting a possible new phase of ice at temperatures between 4 and 50 K.

  10. Hafnium-an optical hydrogen sensor spanning six orders in pressure.

    Science.gov (United States)

    Boelsma, C; Bannenberg, L J; van Setten, M J; Steinke, N-J; van Well, A A; Dam, B

    2017-06-05

    Hydrogen detection is essential for its implementation as an energy vector. So far, palladium is considered to be the most effective hydrogen sensing material. Here we show that palladium-capped hafnium thin films show a highly reproducible change in optical transmission in response to a hydrogen exposure ranging over six orders of magnitude in pressure. The optical signal is hysteresis-free within this range, which includes a transition between two structural phases. A temperature change results in a uniform shift of the optical signal. This, to our knowledge unique, feature facilitates the sensor calibration and suggests a constant hydrogenation enthalpy. In addition, it suggests an anomalously steep increase of the entropy with the hydrogen/metal ratio that cannot be explained on the basis of a classical solid solution model. The optical behaviour as a function of its hydrogen content makes hafnium well-suited for use as a hydrogen detection material.

  11. Hafnium—an optical hydrogen sensor spanning six orders in pressure

    Science.gov (United States)

    Boelsma, C.; Bannenberg, L. J.; van Setten, M. J.; Steinke, N.-J.; van Well, A. A.; Dam, B.

    2017-01-01

    Hydrogen detection is essential for its implementation as an energy vector. So far, palladium is considered to be the most effective hydrogen sensing material. Here we show that palladium-capped hafnium thin films show a highly reproducible change in optical transmission in response to a hydrogen exposure ranging over six orders of magnitude in pressure. The optical signal is hysteresis-free within this range, which includes a transition between two structural phases. A temperature change results in a uniform shift of the optical signal. This, to our knowledge unique, feature facilitates the sensor calibration and suggests a constant hydrogenation enthalpy. In addition, it suggests an anomalously steep increase of the entropy with the hydrogen/metal ratio that cannot be explained on the basis of a classical solid solution model. The optical behaviour as a function of its hydrogen content makes hafnium well-suited for use as a hydrogen detection material. PMID:28580959

  12. Influence of hydrogen on the oxygen solubility in Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Guilbert-Banti, Séverine, E-mail: severine.guilbert@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, SEREX/LE2M, Bâtiment 327, BP3, 13115 Saint Paul lez Durance (France); Lacote, Pauline; Taraud, Gaëlle [Institut de Radioprotection et de Sûreté Nucléaire, SEREX/LE2M, Bâtiment 327, BP3, 13115 Saint Paul lez Durance (France); Berger, Pascal [NIMBE, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); Desquines, Jean; Duriez, Christian [Institut de Radioprotection et de Sûreté Nucléaire, SEREX/LE2M, Bâtiment 327, BP3, 13115 Saint Paul lez Durance (France)

    2016-02-15

    Despite the influence of hydrogen on the behavior of zirconium fuel cladding in many nuclear safety issues, the pseudo-binary Zircaloy-4 – oxygen phase diagram still lacks of data, especially above 1000 °C. The aim of this study was to provide experimental data to better assess the influence of hydrogen on the oxygen solubility in Zircaloy-4. Homogenized two-phase Zircaloy-4 samples were elaborated from 300 to 1000 wppm pre-hydrided samples. Local distributions were characterized thoroughly using Electron Probe Micro-Analysis (EPMA) for oxygen and Elastic Recoil Detection Analysis (ERDA) for hydrogen. The data obtained in this work were included in the pseudo-binary Zircaloy-4 – oxygen phase diagram and have shown that hydrogen has limited influence on the α + β → β transus. Regarding the α → α + β transus, no influence of hydrogen concentration in the α phase below 400 wppm was evidenced.

  13. Electrochemical Hydrogen Storage in a Highly Ordered Mesoporous Carbon

    OpenAIRE

    Dan eLiu; Chao eZeng; Haolin eTan; Dong eZheng; Rong eLi; Deyu eQu; zhizhong eXie; Jiahen eLei; Liang eXiao; Deyang eQu

    2014-01-01

    A highly ordered mesoporous carbon (HOMC) has been synthesized through a strongly acidic, aqueous cooperative assembly route. The structure and morphology of the carbon material were investigated using TEM, SEM, and nitrogen adsorption–desorption isotherms. The carbon was proven to be meso-structural and consisted of graphitic micro-domain with larger interlayer space. Active carbon impedance and electrochemical measurements reveal that the synthesized highly ordered mesoporous carbon (HOMC) ...

  14. Influence of the Ambient Temperature, to the Hydrogen Fuel Cell Functioning

    Directory of Open Access Journals (Sweden)

    POPOVICI Ovidiu

    2012-10-01

    Full Text Available The reversible fuel cell can be used to produce hydrogen. The hydrogen is further the chemical energy source to produce electrical energy using the fuel cell. The ambient temperature will influence theparameters of the hydrogen fuel cell.

  15. A second order thermodynamic perturbation theory for hydrogen bond cooperativity in water

    OpenAIRE

    Marshall, Bennett D.

    2017-01-01

    It has been extensively demonstrated through first principles quantum mechanics calculations that water exhibits strong hydrogen bond cooperativity. Classical molecular simulation and statistical mechanics methods typically assume pairwise additivity, meaning they cannot account for these 3-body and higher cooperative effects. In this document, we extend second order thermodynamic perturbation theory to correct for hydrogen bond cooperativity in 4 site water. We show that the association theo...

  16. Cosmological hydrogen recombination: influence of resonance and electron scattering

    Science.gov (United States)

    Chluba, J.; Sunyaev, R. A.

    2009-08-01

    In this paper we consider the effects of resonance and electron scattering on the escape of Lyman α photons during cosmological hydrogen recombination. We pay particular attention to the influence of atomic recoil, Doppler boosting, and Doppler broadening using a Fokker-Planck approximation of the redistribution function describing the scattering of photons on the Lyman α resonance of moving hydrogen atoms. We extend the computations of our recent paper on the influence of the 3d/3s-1s two-photon channels on the dynamics of hydrogen recombination, simultaneously including the full time dependence of the problem, the thermodynamic corrections factor, leading to a frequency-dependent asymmetry between the emission and absorption profile, and the quantum-mechanical corrections related to the two-photon nature of the 3d/3s-1s emission and absorption process on the exact shape of the Lyman α emission profile. We show here that, because of the redistribution of photons over frequency hydrogen recombination is sped up by Δ N_e/ Ne ~ -0.6% at z ~ 900. For the CMB temperature and polarization power spectra, this results in |Δ C_l/C_l| ~ 0.5-1% at ly ⪆ 1500, which is in turn important for analyzing future CMB data in the context of the Planck Surveyor, Spt, and Act. The main contribution to this correction comes from the atomic recoil effect (Δ N_e/ Ne ~ -1.2% at z ~ 900), while Doppler boosting and Doppler broadening partially cancel this correction, again slowing hydrogen recombination down by Δ N_e/ Ne ~ 0.6% at z ~ 900. The influence of electron scattering close to the maximum of the Thomson visibility function at z ~ 1100 can be neglected. We also give the cumulative results, in addition including the time-dependent correction, the thermodynamic factor, and the correct shape of the emission profile. This amounts to Δ N_e/ Ne ~ -1.8% at z ~ 1160 and |Δ C_l/C_l| ~ 1-3% at l ⪆ 1500.

  17. Gas-phase hydrogenation influence on defect behavior in titanium-based hydrogen-storage material

    OpenAIRE

    Laptev, Roman S.; Viktor N. Kudiiarov; Bordulev, Yuri S.; Mikhaylov, Andrey A.; Andrey M. Lider

    2017-01-01

    Titanium and its alloys are promising materials for hydrogen storage. However, hydrogen penetration accompanies the exploitation of hydrogen storage alloys. In particular, hydrogen penetration and accumulation in titanium alloys changes their mechanical properties. Therefore, the research works of such materials are mainly focused on improving the reversibility of hydrogen absorption-liberation processes, increasing the thermodynamic characteristics of the alloys, and augmenting their hydroge...

  18. Influence of hydrogen on corrosion and stress induced cracking of stainless steel

    OpenAIRE

    Kivisäkk, Ulf

    2010-01-01

    Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. Some aspects of the effect of hydrogen on corrosion and hydrogen-induced stress cracking, HISC, of stainless steels were studied in this work. These aspects rel...

  19. Comment on "Evidence of a first-order phase transition to metallic hydrogen"

    Science.gov (United States)

    Howie, Ross T.; Dalladay-Simpson, Philip; Gregoryanz, Eugene

    2017-10-01

    A recent article by Zaghoo et al. [Phys. Rev. B 93, 155128 (2016), 10.1103/PhysRevB.93.155128] presented high-pressure high-temperature optical experiments claiming the observation of a first-order transition to atomic liquid metallic hydrogen. Here, we demonstrate that the experimental evidence presented is unsubstantial for such a claim. Furthermore, the claimed results and conclusions contradict previously published works, including those by the same research group.

  20. Influence of magnetic anisotropy on the superferromagnetic ordering in nanocomposites

    DEFF Research Database (Denmark)

    Mørup, Steen; Christiansen, Gunnar Dan

    1993-01-01

    Magnetic interaction between ultrafine particles may result in superferromagnetism, i.e., ordering of the magnetic moments of particles which would be superparamagnetic if they were noninteracting. In this article we discuss the influence of the magnetic anisotropy on the temperature dependence o...... of the order parameter. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  1. Gas-phase hydrogenation influence on defect behavior in titanium-based hydrogen-storage material

    Directory of Open Access Journals (Sweden)

    Roman S. Laptev

    2017-02-01

    Full Text Available Titanium and its alloys are promising materials for hydrogen storage. However, hydrogen penetration accompanies the exploitation of hydrogen storage alloys. In particular, hydrogen penetration and accumulation in titanium alloys changes their mechanical properties. Therefore, the research works of such materials are mainly focused on improving the reversibility of hydrogen absorption-liberation processes, increasing the thermodynamic characteristics of the alloys, and augmenting their hydrogen storage capacity. In the process of hydrogenation-dehydrogenation, the formed defects both significantly reduce hydrogen storage capacity and can also be used to create effective traps for hydrogen. Therefore, the investigation of hydrogen interaction with structural defects in titanium and its alloys is very important. The present work, the hydrogen-induced formation of defects in the alloys of commercially pure titanium under temperature gas-phase hydrogenation (873 K has studied by positron lifetime spectroscopy and Doppler broadening spectroscopy. Based on the evolution of positron annihilation parameters τf, τd, their corresponding intensities If, Id and relative changes of parameters S/S0 and W/W0, the peculiarities of hydrogen interaction with titanium lattice defects were investigated in a wide range of hydrogen concentrations from 0.8at% to 32.0at%.

  2. Influence of surface roughness on consecutively hydrogen absorption cycles in Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Suarez, Alejandra [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, Mexico D.F. 01000 (Mexico)

    2010-10-15

    In the present work the influence of roughness of the material surface with hydrogen absorption in Ti-6Al-4V alloy during four hydrogenated cycles is studied. The Ti-6Al-4V alloy samples were hydrogenated during several cycles at 650 C for two hours, in 50% hydrogen and 50% argon atmospheres, 1 atm pressure and a flux of 50 cm{sup 3}/min each one. The hydrogen concentrations are measured using Elastic Recoil Detection Analysis technique; meanwhile the roughness is measured using an Atomic Force Microscope. X-ray Diffraction analysis shows changes in crystal orientation due to hydrogen absorption. The hydrogen capacity of the Ti-6Al-4V alloy is observed to be directly correlated to the surface quality of the sample during the first hydrogenation cycles, but in the fourth cycle, the hydrogen absorption is almost equal for all the samples independently of their surface roughness. (author)

  3. PROTON ORDERING MODEL OF PHASE TRANSITIONS IN HYDROGEN BONDED FERRIELECTRIC TYPE SYSTEMS: THE GPI CRYSTAL

    Directory of Open Access Journals (Sweden)

    I.Stasyuk

    2003-01-01

    Full Text Available A microscopic model based on the consideration of the proton ordering is proposed for describing the H-bonded ferroelectric crystalline systems with a complex structure of the hydrogen bond network. The model has been used for the investigation of thermodynamics and dielectric properties of the GPI crystal. The symmetry analysis of the order parameters responsible for the mixed (ferro- and antiferroelectric nature of ordering is performed within the model. The phase transition into the ferroelectric state is described. Changes in the dielectric susceptibility of the crystal are studied in the presence of the transverse external electric field acting along the c-axis. The results of measurements of temperature and field dependences of dielectric permittivity εc' in the paraelectric phase are presented. The microscopic mechanism of the observed effects is discussed based on the comparison of theoretical results and experimental data. A conclusion is made about the significant role of the ionic groups connected by hydrogen bonds in the charge transfer. So they make an important contribution into the polarizability of the GPI crystal along the direction of H-bonded chains.

  4. Influence of colectomy on hydrogen excretion in breath.

    Science.gov (United States)

    Casellas, Francesc; Torrejón, A; Vilaseca, J; Aparici, A; Casaus, M; Rodríguez, P; Guarner, F

    2010-04-01

    Hydrogen breath test is the most commonly used method to analyze carbohydrate absorption and diagnose carbohydrate malabsorption. The result of the H(2) breath test is influenced by different factors, which are mostly related to quantitative or qualitative aspects of colonic flora. A scarcely studied variable is the effect of colonic anatomical integrity on H(2) excretion in breath. The present study aims to determine whether loss of colonic integrity reduces H(2) excretion capacity after an oral load of an unabsorbable carbohydrate. An observational study was conducted in three patient groups: controls with preserved colon, patients with partial colectomy, and patients with complete colectomy and ileostomy. H(2) concentration in breath was measured by gas chromatography every 10 min for 3 h after oral lactulose administration. Twenty-two patients with partial colectomy, 18 controls with preserved colon, and seven patients with ileostomy were included. H(2) excretion after lactulose did not differ between patients with partial colectomy and controls (basal excretion = 8.5 vs 4 ppm; delta increase = 50.0 vs 47.5 ppm; area under the curve = 4,480.0 vs 4,710.5 ppm/min). In contrast, H(2) excretion was significantly lower in the ileostomy group. Partial colectomy does not influence the capacity for H(2) excretion after oral unabsorbable carbohydrate administration.

  5. Influence of strontium on the cubic to ordered hexagonal phase ...

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia. Home; Journals; Bulletin of Materials Science; Volume 23; Issue 6. Influence of strontium on the cubic to ordered hexagonal phase transformation in barium magnesium niobate. M Thirumal A K Ganguli. Phase Transitions Volume 23 Issue 6 December 2000 pp 495-498 ...

  6. Processing two tasks with varying task order: central stage duration influences central processing order.

    Science.gov (United States)

    Ruiz Fernández, Susana; Leonhard, Tanja; Rolke, Bettina; Ulrich, Rolf

    2011-05-01

    In a recent study, Sigman and Dehaene (2006, PLoS Biology, 4, 1227-1238) reported that perceptual processing duration influences processing order of two tasks in the psychological refractory period paradigm (PRP). The present study examines whether the duration of central processes also influences processing order. For this purpose, we employed letter tasks with different central processing durations and varied task order in the PRP. In one part of the experiment, a tone discrimination task was combined with a similar time-consuming letter discrimination task. In the other part, the tone task was combined with a more time-consuming letter task, which required a mental rotation of the letter thereby prolonging central processing. If the duration of central processes influences processing order, participants should perform the tone task first more often when it is presented with the more time-consuming mental rotation task, than when it is presented with the similar time-consuming letter task. The results clearly confirm this prediction and thus show that not only perceptual processing duration but also central processing duration affects processing order in a dual-task situation. We suggest that the reported effect mirrors a tendency of participants to minimize total reaction time to both tasks by reducing slack time. 2011 Elsevier B.V. All rights reserved.

  7. Reduced-order modellin for high-pressure transient flow of hydrogen-natural gas mixture

    Science.gov (United States)

    Agaie, Baba G.; Khan, Ilyas; Alshomrani, Ali Saleh; Alqahtani, Aisha M.

    2017-05-01

    In this paper the transient flow of hydrogen compressed-natural gas (HCNG) mixture which is also referred to as hydrogen-natural gas mixture in a pipeline is numerically computed using the reduced-order modelling technique. The study on transient conditions is important because the pipeline flows are normally in the unsteady state due to the sudden opening and closure of control valves, but most of the existing studies only analyse the flow in the steady-state conditions. The mathematical model consists in a set of non-linear conservation forms of partial differential equations. The objective of this paper is to improve the accuracy in the prediction of the HCNG transient flow parameters using the Reduced-Order Modelling (ROM). The ROM technique has been successfully used in single-gas and aerodynamic flow problems, the gas mixture has not been done using the ROM. The study is based on the velocity change created by the operation of the valves upstream and downstream the pipeline. Results on the flow characteristics, namely the pressure, density, celerity and mass flux are based on variations of the mixing ratio and valve reaction and actuation time; the ROM computational time cost advantage are also presented.

  8. Influence of screening effect on hydrogen passivation of hole silicon

    CERN Document Server

    Aleksandrov, O V

    2002-01-01

    The simulation of hole silicon passivation during hydrogen diffusion with account of hydrogen-acceptor pairs formation, internal electrical field and screening effect has been carried out. Screening by free carriers of hydrogen and acceptor ions results in shortening their interaction radii and slacking the concentration dependence of hydrogen diffusivity at high level of silicon doping. The consistency of simulated and experimental profiles of holes and hydrogen-acceptor pairs is reached in a broad band of doping levels from 4 x 10 sup 1 sup 4 to 1.2 x 10 sup 2 sup 0 cm sup - sup 3 at the pair binding energy of 0.70-0.79 eV while the radius of the Coulomb interaction of hydrogen and boron ions is equal to 35 A under low doping and decrease with increasing doping level

  9. Influence of titanium and vanadium on the hydrogen transport through amorphous alumina films

    Energy Technology Data Exchange (ETDEWEB)

    Palsson, G.K. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Wang, Y.T. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Azofeifa, D. [Centro de Investigacion en Ciencia e Ingenieria de Materiales and Escuela de Fisica, Universidad de Costa Rica, San Jose (Costa Rica); Raanaei, H. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Department of Physics, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Sahlberg, M. [Department of Materials Chemistry, Uppsala University, Box 538, S-751 21 Uppsala (Sweden); Hjoervarsson, B. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden)

    2010-04-02

    The influence of titanium and vanadium on the hydrogen transport rate through thin amorphous alumina films is addressed. Only small changes in the transport rate are observed when the Al{sub 2}O{sub 3} are covered with titanium or vanadium. This is in stark contrast to results with a Pd overlayer, which enhances the transport by an order of magnitude. Similarly, when titanium is embedded into the alumina the transport rate is faster than for the covered case but still slower than the undoped reference. Embedding vanadium in the alumina does not yield an increase in uptake rate compared to the vanadium covered oxide layers. These results add to the understanding of the hydrogen uptake of oxidized metals, especially the alanates, where the addition of titanium has been found to significantly enhance the rate of hydrogen uptake. The current findings eliminate two possible routes for the catalysis of alanates by Ti, namely dissociation and effective diffusion short-cuts formed by Ti. Finally, no photocatalytic enhancement was noticed on the titanium covered samples.

  10. Electrochemical Hydrogen Evolution at Ordered Mo 7 Ni 7

    Energy Technology Data Exchange (ETDEWEB)

    Csernica, Peter M. [Department; McKone, James R. [Department; Mulzer, Catherine R. [Dow Electronic Materials, Marlborough Massachusetts 01752, United States; Dichtel, William R. [Department; Abruña, Héctor D. [Department; DiSalvo, Francis J. [Department

    2017-04-11

    Ni–Mo alloys containing up to ~15 mol % Mo are excellent non-noble electrocatalysts for the hydrogen evolution reaction (HER) in alkaline aqueous electrolytes. To date, studies have not addressed the details of HER activity of ordered Ni–Mo intermetallic compounds, which can contain a significantly larger fraction of Mo (up to 50 mol %) than can be accessed through high-temperature alloying. Here, we present a straightforward and facile synthesis of three phase-pure electrocatalyst powders using a precipitation–reduction approach: ordered Mo7Ni7, disordered Ni0.92Mo0.08, and pure Ni. The Ni0.92Mo0.08 alloy exhibited a nearly 10-fold higher mass-specific HER activity than either pure Ni or Mo7Ni7, where much of the difference could be attributed to relative surface area. Therefore, we attempted to quantify and account for differences in surface areas using electron microscopy, impedance spectroscopy, and gas adsorption measurements. These data suggest that Ni–Mo alloys and intermetallic compounds exhibit substantial pseudocapacitance at potentials near the onset of hydrogen evolution, which can cause impedance spectroscopy to overestimate the interfacial capacitance, and thus the electrochemically active surface area, of these materials. From these observations, we postulate Mo redox activity as the chemical basis for the observed pseudocapacitance of Ni–Mo composites. Furthermore, using gas adsorption measurements, rather than capacitance, to estimate active surface area, we find that ordered Mo7Ni7 is more intrinsically active than the Ni0.92Mo0.08 alloy, implying that Mo7Ni7 intermetallics with high surface area will also give higher mass-specific activities than alloys with comparable roughness.

  11. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  12. The Influence of Small Monovalent Cations on Neighbouring Hydrogen Bonds of Aquo-Protein Complexes

    Science.gov (United States)

    Sagarik, Kritsana P.; Rode, Bernd M.

    1981-12-01

    The influence of small monovalent metal ions on hydrogen bonds of aquo-protein complexes is studied on Li+/HCONH2-OH2 as an example. Using results obtained from ab initio calculations with minimal GLO basis sets, the remarkable changes in the hydrogen bond energy and charge distribution, due to metal ion complex formation, are discussed. The metal ion seems to enhance strongly the donor-acceptor interaction of the O ... H-N-C=0 hydrogen-bonded system.

  13. Methane catalytic decomposition over ordered mesoporous carbons: A promising route for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Botas, J.A.; Serrano, D.P. [Department of Chemical and Environmental Technology, ESCET, Rey Juan Carlos University, c/ Tulipan s/n, 28933 Mostoles, Madrid (Spain); IMDEA Energia, c/Tulipan s/n, 28933 Mostoles, Madrid (Spain); Guil-Lopez, R.; Pizarro, P.; Gomez, G. [Department of Chemical and Environmental Technology, ESCET, Rey Juan Carlos University, c/ Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2010-09-15

    Methane decomposition offers an interesting route for the CO{sub 2}-free hydrogen production. The use of carbon catalysts, in addition to lowering the reaction temperature, presents a number of advantages, such as low cost, possibility of operating under autocatalytic conditions and feasibility of using the produced carbons in non-energy applications. In this work, a novel class of carbonaceous materials, having an ordered mesoporous structure (CMK-3 and CMK-5), has been checked as catalysts for methane decomposition, the results obtained being compared to those corresponding to a carbon black sample (CB-bp) and two activated carbons, presenting micro- (AC-mic) and mesoporosity (AC-mes), respectively. Ordered mesoporous carbons, and especially CMK-5, possess a remarkable activity and stability for the hydrogen production through that reaction. Under both temperature programmed and isothermal experiments, CMK-5 has shown to be a superior catalyst for methane decomposition than the AC-mic and CB-bp materials. Likewise, the catalytic activity of CMK-5 is superior to that of AC-mes in spite of the presence of mesoporosity and a high surface area in the latter. The remarkable stability of the CMK-5 catalyst is demonstrated by the high amount of carbon deposits that can be formed on this sample. This result has been assigned to the growth of the carbon deposits from methane decomposition towards the outer part of the catalyst particles, avoiding the blockage of the uniform mesopores present in CMK-5. Thus, up to 25 g of carbon deposits have been formed per gram of CMK-5, while the latter still retains a significant catalytic activity. (author)

  14. Dependence of the electron work function change of the rhodium (100) face on the order of oxygen and hydrogen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Kalish, T.V.; Belyaeva, M.E.

    1988-03-01

    It has been shown that the order of hydrogen and oxygen adsorption on rhodium determines the course of the adsorbates interaction. Changes in electron work function of the rhodium (100) face which occur as a function of time during hydrogen adsorption on a surface with preadsorbed oxygen was studied along with changes in the electron work function during adsorption of hydrogen and oxygen. The electron work function was determined by photoelectric emission. Gas adsorption occurred at room temperature, the gas phase composition was determined with an omegatron, and Auger spectroscopy was used to check the cleanliness of the original surface.

  15. The Influence of Opacity on Hydrogen Line Emission and Ionisation Balance in High Density Divertor Plasmas

    OpenAIRE

    Behringer, K.

    1997-01-01

    The influence of opacity on hydrogen line emission and ionisation balance in high density divertor plasmas. - Garching bei München : Max-Planck-Inst. für Plasmaphysik, 1997. - 21 S. - (IPP-Report ; 10/5)

  16. The influence of hydrogen on the fatigue life of metallic leaf spring components in a vacuum environment

    NARCIS (Netherlands)

    Kouters, M.H.M.; Slot, H.M.; Zwieten, W. van; Veer, J. van der

    2014-01-01

    Hydrogen is used as a process gas in vacuum environments for semiconductor manufacturing equipment. If hydrogen dissolves in metallic components during operation it can result in hydrogen embrittlement. In order to assess if hydrogen embrittlement occurs in such a vacuum environment a special

  17. Direct observation and modelling of ordered hydrogen adsorption and catalyzed ortho-para conversion on ETS-10 titanosilicate material.

    Science.gov (United States)

    Ricchiardi, Gabriele; Vitillo, Jenny G; Cocina, Donato; Gribov, Evgueni N; Zecchina, Adriano

    2007-06-07

    Hydrogen physisorption on porous high surface materials is investigated for the purpose of hydrogen storage and hydrogen separation, because of its simplicity and intrinsic reversibility. For these purposes, the understanding of the binding of dihydrogen to materials, of the structure of the adsorbed phase and of the ortho-para conversion during thermal and pressure cycles are crucial for the development of new hydrogen adsorbents. We report the direct observation by IR spectroscopic methods of structured hydrogen adsorption on a porous titanosilicate (ETS-10), with resolution of the kinetics of the ortho-para transition, and an interpretation of the structure of the adsorbed phase based on classical atomistic simulations. Distinct infrared signals of o- and p-H2 in different adsorbed states are measured, and the conversion of o- to p-H2 is monitored over a timescale of hours, indicating the presence of a catalyzed reaction. Hydrogen adsorption occurs in three different regimes characterized by well separated IR manifestations: at low pressures ordered 1:1 adducts with Na and K ions exposed in the channels of the material are formed, which gradually convert into ordered 2:1 adducts. Further addition of H2 occurs only through the formation of a disordered condensed phase. The binding enthalpy of the Na+-H2 1:1 adduct is of -8.7+/-0.1 kJ mol(-1), as measured spectroscopically. Modeling of the weak interaction of H2 with the materials requires an accurate force field with a precise description of both dispersion and electrostatics. A novel three body force field for molecular hydrogen is presented, based on the fitting of an accurate PES for the H2-H2 interaction to the experimental dipole polarizability and quadrupole moment. Molecular mechanics simulations of hydrogen adsorption at different coverages confirm the three regimes of adsorption and the structure of the adsorbed phase.

  18. Influence of hydrogen bonding on the generation and stabilization of ...

    Indian Academy of Sciences (India)

    Induction and stabilization of liquid crystallinity through hydrogen bonding (HB) are now well-established. Interesting observations made on the influence of HB on LC behaviour of amido diol-based poly(esteramide)s, poly(esteramide)s containing nitro groups and azobenzene mesogen-based polyacrylates will be ...

  19. Influence of hydrogen on chemical vapour synthesis of different ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The role of hydrogen in the catalytic chemical vapour deposition of carbon nanotubes using sputtered nickel thin film as a catalyst is explained in this work. The growth of different carbon nanostruc- tures with the variation in the precursor gas content was studied by keeping all other process parameters constant ...

  20. Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M.

    1943-02-19

    A transcript is presented of a speech on the history of the development of hydrogenation of coal and tar. Apparently the talk had been accompanied by the showing of photographic slides, but none of the pictures were included with the report. In giving the history, Dr. Pier mentioned the dependence of much of the development of hydrogenation upon previous development in the related areas of ammonia and methanol syntheses, but he also pointed out several ways in which equipment appropriate for hydrogenation differed considerably from that used for ammonia and methanol. Dr. Pier discussed the difficulties encountered with residue processing, design of the reaction ovens, manufacture of ovens and preheaters, heating of reaction mixtures, development of steels, and development of compressor pumps. He described in some detail his own involvement in the development of the process. In addition, he discussed the development of methods of testing gasolines and other fuels. Also he listed some important byproducts of hydrogenation, such as phenols and polycyclic aromatics, and he discussed the formation of iso-octane fuel from the butanes arising from hydrogenation. In connection with several kinds of equipment used in hydrogenation (whose pictures were being shown), Dr. Pier gave some of the design and operating data.

  1. The influence of metal- and N-species addition in mesoporous carbons on the hydrogen adsorption capacity

    Energy Technology Data Exchange (ETDEWEB)

    Cai, J. [Université Lyon 1, CNRS UMR5256, Institut de Recherches sur la Catalyse et l' Environnement de Lyon, 2 Av. Einstein, 69626 Villeurbanne (France); Bennici, S., E-mail: simona.bennici@ircelyon.univ-lyon1.fr [Université Lyon 1, CNRS UMR5256, Institut de Recherches sur la Catalyse et l' Environnement de Lyon, 2 Av. Einstein, 69626 Villeurbanne (France); Shen, J. [Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Auroux, A. [Université Lyon 1, CNRS UMR5256, Institut de Recherches sur la Catalyse et l' Environnement de Lyon, 2 Av. Einstein, 69626 Villeurbanne (France)

    2015-07-01

    Mesoporous carbon (MC) and two types of N-containing mesoporous carbons (N-MC and C{sub 3}N{sub 4}-MC) were prepared from cost-effective materials and used for hydrogen storage both at 77 K and room temperature (RT). The mesoporous structure was confirmed by N{sub 2} adsorption isotherm at 77 K, and the characterization of the bulk and surface properties performed by ICP analysis, TEM, XRD, and XPS. The maximum hydrogen uptakes were found on N-MC (1.1 wt% of hydrogen) at 100 bar and RT and on MC (3.07 wt% of hydrogen) at 40 bar and 77 K. Pt, Pd, and Ru noble-metal were also added to the three carbon based supports in order to verify the existence of any spillover effect due to the metals presence and evaluate the influence on hydrogen storage capacity. - Highlights: • Biomass derived mesoporous carbons were modified by N and noble metal addition. • N atoms enhance the H{sub 2} adsorption capacity of mesoporous carbon at room temperature. • Ru/N-MC reaches the maximum theoretical limit of H{sub 2} storage for carbon materials.

  2. Influence of qualitative composition of raw materials on the production of hydrogen by microorganisms

    Directory of Open Access Journals (Sweden)

    Н. Б. Голуб

    2013-07-01

    Full Text Available The aim was to study the influence of the quality of the agricultural waste materials to the process of producing hydrogen group of microorganisms. Researches were conducted by microbiological and chromatographic methods of analysis. The process of producing hydrogen passes using agricultural waste in anaerobic mesophilic regime for the use of groups of microorganisms. On all types of waste found production of hydrogen. The pretreatment of raw material increases access of microorganisms to nutrients, destruction of lignino-cellulosic frame and decontamination of methanegenic bacterias. The aging of culture leads to transition the butyric type of fermentation to acetone-butyric type, which causes decreasing the yield of hydrogen. The maximum yield of hydrogen was 128 g H2 per kg of cellulose. It was obtained by using barley straw as raw material, which contains great amount of hemicelluloses.

  3. The Influence of Hydrogen Gas on the Measures of Efficiency of Diesel Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Jurgis Latakas

    2014-12-01

    Full Text Available In this research paper energy and ecological parameters of diesel engine which works under addition of hydrogen (10, 20, 30 l/ min are presented. A survey of research literature has shown that addition of hydrogen gases improve diesel combustion; increase indicated pressure; decrease concentration of carbon dioxide (CO2, hydrocarbons (HC, particles; decrease fuel consumptions. Results of the experiment revealed that hydrogen gas additive decreased pressure in cylinder in kinetic combustion phase. Concentration of CO2 and nitrous oxides (NOx decreased not significantly, HC – increased. Concentration of particles in engine exhaust gases significantly decreased. In case when hydrogen gas as additive was supplied, the fuel consumptions decreased a little. Using AVL BOOST software combustion process analysis was made. It was determined that in order to optimize engine work process under hydrogen additive usage, it is necessary to adjust diesel injection angle.

  4. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

    The idea of a "Hydrogen Economy" is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO₂ in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H₂ from the electrolyzer. Methanol made with CO₂ from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan). Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs) by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  5. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

    Full Text Available The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan. Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  6. Multi-Scale Ordered Cell Structure for Cost Effective Production of Hydrogen by HTWS

    Energy Technology Data Exchange (ETDEWEB)

    Elangovan, Elango [Ceramatec, Inc., West Valley City, UT (United States); Rao, Ranjeet [PARC, Palo Alto, CA (United States); Colella, Whitney [Gaia Energy Research Inst. LLC, Arlington, VA (United States)

    2017-12-20

    Production of hydrogen using an electrochemical device provides for large scale, high efficiency conversion and storage of electrical energy. When renewable electricity is used for conversion of steam to hydrogen, a low-cost and low emissions pathway to hydrogen production emerges. This project was intended to demonstrate a high efficiency High Temperature Water Splitting (HTWS) stack for the electrochemical production of low cost H2. The innovations investigated address the limitations of the state of the art through the use of a novel architecture that introduces macro-features to provide mechanical support of a thin electrolyte, and micro-features of the electrodes to lower polarization losses. The approach also utilizes a combination of unique sets of fabrication options that are scalable to achieve manufacturing cost objectives. The development of HTWS process and device is guided by techno-economic and life cycle analyses.

  7. THE INFLUENCE OF HYDROGEN ON THE PLASTIC PROPERTIES OF THE REINFORCING BARS

    Directory of Open Access Journals (Sweden)

    E. P. Baradyntseva

    2013-01-01

    Full Text Available The research carried out in laboratory of metal science on detection of hydrogen presence in reinforcement depending on period of aging and reinforcement profile and also its influence on plastic properties of reinforcing bar is described in this article. The method of glycerine tests was applied for identification of hydrogen presence in finished reinforcing bar, the essence of which is in the fact that at gas emission from metal the bubbles stay too long on the surface of cross samples under glycerin layer. The revealed regularities enable to recommend actions for providing stable mechanical properties of the heat-strengthened reinforcement by creation of conditions for lowering of steel saturation with hydrogen, preventing thereby occurrence of hydrogen embrittlement of reinforcement on JSC «BMZ» – management company of holding «BMK».

  8. An Influence Study of Hydrogen Evolution Characteristics on the Negative Strap Corrosion of Lead Acid Battery

    Directory of Open Access Journals (Sweden)

    Zhong Guobin

    2015-01-01

    Full Text Available Negative strap corrosion is an important reason for the failure of valve regulated lead acid battery. This paper selected the Pb-Sb alloy material and Pb-Sn alloy material, made an investigation on the negative corrosion resistance and hydrogen evolution of these two alloy materials by scanning electron microscope analysis, metallographic analysis, chemical study and linear sweep voltammetry, and discussed the influence of lead alloy hydrogen evolution on the negative strap corrosion. The results showed that the hydrogen evolution reaction rates of the alloys had an impact on the corrosion areas with the maximum thickness of the alloys and the depth of corrosion layers. Greater hydrogen evolution reaction rate can lead to shorter distance between the corrosion area with the maximum thickness and the liquid level; whereas the greater corrosion layer thickness can bring aggravated risk of negative strap corrosion failure.

  9. Anisotropic intermolecular interactions and rotational ordering in hydrogen containing solids. Final report, January 1, 1972--June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    White, D.

    1978-01-01

    Thermodynamic properties, order-disorder phenomena, optical, electric and magnetic properties of hydrogen-containing molecular solids have been investigated. A summary of the findings of this 6 year research program is presented here. The approach in these studies was (a) thermodynamic and transport studies extending to very low temperatures, (b) pulsed NMR studies for determination of structural parameters important to spin-lattice relaxation, and (c) pulsed laser studies for the investigation of excitations and energy transfer mechanisms in solids. (GHT)

  10. Influence of the C content on the permeation of hydrogen in Fe alloys with low contents of C

    Directory of Open Access Journals (Sweden)

    I. Peñalva

    2016-12-01

    The experimental permeation results were analyzed using a non-linear least square fitting. The final resulting values of the permeability were paired off in order to determine the effect of the C content: pure Fe versus FeC, FeP versus FePC and Fe10%Cr versus Fe10%CrC. According to the results, the influence of the metallurgical composition of C in Fe alloys on the permeability of hydrogen is discussed together with the synergistic effects caused by the presence of P and Cr.

  11. The influence of hydrogen peroxide and hydrogen on the corrosion of simulated spent nuclear fuel.

    Science.gov (United States)

    Razdan, Mayuri; Shoesmith, David W

    2015-01-01

    The synergistic influence between H(2)O(2) and H(2) on the corrosion of SIMFUEL (simulated spent nuclear fuel) has been studied in solutions with and without added HCO(3)(-)/CO(3)(2-). The response of the surface to increasing concentrations of added H(2)O(2) was monitored by measuring the corrosion potential in either Ar or Ar/H(2)-purged solutions. Using X-ray photoelectron spectroscopy it was shown that the extent of surface oxidation (U(V) + U(VI) content) was directly related to the corrosion potential. Variations in corrosion potential with time, redox conditions, HCO(3)(-)/CO(3)(2-) concentration, and convective conditions showed that surface oxidation induced by H(2)O(2) could be reversed by reaction with H(2), the latter reaction occurring dominantly on the noble metal particles in the SIMFUEL. For sufficiently large H(2)O(2) concentrations, the influence of H(2) was overwhelmed and irreversible oxidation of the surface to U(VI) occurred. Subsequently, corrosion was controlled by the chemical dissolution rate of this U(VI) layer.

  12. Density dependence of hydrogen bonding and the translational-orientational structural order in supercritical water: a molecular dynamics study.

    Science.gov (United States)

    Ma, Haibo; Ma, Jing

    2011-08-07

    Molecular dynamics simulation have been performed with a wide range of densities along a near critical isotherm of supercritical water (SCW) in order to study the density dependence of the structure order and hydrogen bonding (HB). It is revealed that the translational structure order is nearly invariant while the orientational tetrahedral structure order is very sensitive to the bulk density under supercritical conditions. Meanwhile, some energetically unfavorable intermediate water dimer structures are found to appear under supercritical conditions due to the reduced energy difference and the enhanced energy fluctuation. As a consequence, a general geometrical criterion or the inclusion of a energy-based criterion instead of currently widely adopted pure r(OH)-based geometric criterion is suggested to be used in the HB statistics under supercritical conditions. It is found that the average HB number per H(2)O molecule (n(HB)) reduces with the decreasing SCW bulk density although a given pair of H(2)O molecules are shown to have a stronger ability to form a hydrogen bond under lower SCW bulk densities. Accordingly, the orientational tetrahedral structure order q decreases with the reducing bulk density under supercritical conditions. However, when the fluid is dilute with ρ ≤ 0.19ρ(c) (ρ(c) = 0.322 g/cm(3)), the energy fluctuation increases sharply and the short-range order is destroyed, signifying the supercritical fluid (SCF)-gas state transition. Accordingly, the orientational tetrahedral structure order q gets reversal around ρ = 0.19ρ(c) and approaches zero under very dilute conditions. The sensitivity of the orientational order to the density implies the microscopic origin of the significant dependence of SCF's physicochemical properties on the pressure.

  13. Influence of thin alien layers on hydrogen reflection and trapping by PFM

    Energy Technology Data Exchange (ETDEWEB)

    Golubeva, A.V.; Kurnaev, V.A. E-mail: kurnaev@plasma.mephi.ru; Levchuk, D.V.; Trifonov, N.N

    2003-03-01

    Investigations of the influence of carbon and hydrocarbon layers on the trapping and reflection of hydrogen isotopes by tungsten were carried out with BCA based computer code SCATTER. It is shown that for small layer thickness the trapping efficiency depends on the hydrocarbon film composition. At layer thickness of a few nanometers energy dependence of the trapping efficiency has a non-monotonous character with a minimum at primary energies about 100-1000 eV and continuous increment with energy at higher energies. The possible reason of this effect is briefly discussed. Comparison between the trapping efficiencies of different hydrogen isotopes in a C-W target is also presented.

  14. Hydrogen influence on the behaviour of alloy 718 in primary water

    Energy Technology Data Exchange (ETDEWEB)

    Foucault, M.; Cloue, J.M. [Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Paris-La-Defense (France); Splimont, J.G.; Andrieu, E. [Ecole Nationale Superieure des Mines, 75 - Paris (France)

    1996-12-31

    Cold-worked and aged alloy 718 is used in nuclear industry for application in primary water. Main risks are stress corrosion cracks (SCC) during high temperature periods, and mechanical characteristics evolution (mainly ductility loss at low temperature) related with hydrogen dissolved in metal. SCC risks can be drastically decreased by a good surface conditioning control. However, hydrogen influence upon mechanical behaviour of this alloy has to be taken into account.It is still badly known and specific studies are actually undertaken on this subject. (authors). 3 refs., 1 fig.

  15. Orientationally ordered ridge structures of aluminum films on hydrogen terminated silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Pantleon, Karen

    2006-01-01

    > directions on the silicon substrate. The ridge structure appears when the film thickness is above 500 nm, and increasing the film thickness makes the structure more distinct. Anodic oxidation enhances the structure even further. X-ray diffraction indicates that grains in the film have mostly (110) facets......Films of aluminum deposited onto Si(100) substrates show a surface structure of parallel ridges. On films deposited on oxidized silicon substrates the direction of the ridges is arbitrary, but on films deposited on hydrogen-terminated Si(100) the ridges are oriented parallel to the

  16. The influence of the small platinum clusters on hydrogen sorption properties

    Science.gov (United States)

    Martyła, Agnieszka; Przekop, R. E.; Osińska-Broniarz, Monika; Kopczyk, M.; Rybka, J. D.; Kirszensztejn, P.

    2017-11-01

    Hydrogen sorption abilities of Pt-B2O3/Al2O3 systems with different molar ratio of oxides obtained by sol-gel method were examined. Platinum was introduced by surface impregnation. Main goal of the research was to check an influence of metallic component (platinum) on sorption properties of B2O3/Al2O3 binary oxides. The oxide systems were characterized using XRD and TEM. Hydrogen adsorption was tested in the volumetric system and TPD measurements were taken. Results show that the amount of adsorbed hydrogen depends not only on the amount of platinum in the system but also on the type of oxide support and mainly on the content of boria.

  17. An unexpected negative influence of light intensity on hydrogen production by dark fermentative bacteria Clostridium beijerinckii.

    Science.gov (United States)

    Zagrodnik, R; Laniecki, M

    2016-01-01

    The role of light intensity on biohydrogen production from glucose by Clostridium beijerinckii, Clostridium acetobutylicum, and Rhodobacter sphaeroides was studied to evaluate the performance and possible application in co-culture fermentation system. The applied source of light had spectrum similar to the solar radiation. The influence of light intensity on hydrogen production in dark process by C. acetobutylicum was negligible. In contrast, dark fermentation by C. beijerinckii bacteria showed a significant decrease (83%) in produced hydrogen at light intensity of 540W/m(2). Here, the redirection of metabolism from acetic and butyric acid formation towards lactic acid was observed. This not yet reported effect was probably caused by irradiation of these bacteria by light within UVA range, which is an important component of the solar radiation. The excessive illumination with light of intensity higher than 200W/m(2) resulted in decrease in hydrogen production with photofermentative bacteria as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Metallic cobalt nanoparticles imbedded into ordered mesoporous carbon: A non-precious metal catalyst with excellent hydrogenation performance.

    Science.gov (United States)

    Liu, Jiangyong; Wang, Zihao; Yan, Xiaodong; Jian, Panming

    2017-11-01

    Ordered mesoporous carbon (OMC)-metal composites have attracted great attention owing to their combination of high surface area, controlled pore size distribution and physicochemical properties of metals. Herein, we report the cobalt nanoparticles/ordered mesoporous carbon (CoNPs@OMC) composite prepared by a one-step carbonization/reduction process assisted by a hydrothermal pre-reaction. The CoNPs@OMC composite presents a high specific surface area of 544m 2 g -1 , and the CoNPs are uniformly imbedded or confined in the ordered mesoporous carbon matrix. When used as a non-precious metal-containing catalyst for hydrogenation reduction of p-nitrophenol and nitrobenzene, it demonstrates high efficiency and good cycling stability. Furthermore, the CoNPs@OMC composite can be directly used to catalyze the Fischer-Tropsch synthesis for the high-pressure CO hydrogenation, and presents a good catalytic selectivity for C 5 + hydrocarbons. The excellent catalytic performance of the CoNPs@OMC composite can be ascribed to synergistic effect between the high specific surface area, mesoporous structure and well-imbedded CoNPs in the carbon matrix. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Influence of hydrogenation on the dark current mechanism of HgCdTe photovoltaic detectors

    Energy Technology Data Exchange (ETDEWEB)

    Qiao Hui; Ye Zhenhua; Li Xiangyang; Gong Haimei [Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Hu Weida, E-mail: qiaohui@mail.sitp.ac.c [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

    2010-03-15

    The influence of hydrogenation on the dark current mechanism of HgCdTe photovoltaic detectors is studied. The hydrogenation is achieved by exposing samples to a H{sub 2}/Ar plasma atmosphere that was produced during a reactive ion etching process. A set of variable-area photomask was specially designed to evaluate the hydrogenation effect. It was found that the current-voltage characteristics were gradually improved when detectors were hydrogenated by different areas. The fitting results of experimental results at reverse bias conditions sustained that the improvement of current-voltage curves was due to the suppression of trap assisted tunneling current and the enhancement of minority lifetime in the depletion region. It was also found that the dominative forward current was gradually converted from a generation-recombination current to a diffusion current with the enlargement of the hydrogenation area, which was infered from the ideality factors by abstraction of forward resistance-voltage curves of different detectors. (semiconductor technology)

  20. Hydrogen/Deuterium Exchange Mass Spectrometry for Probing Higher Order Structure of Protein Therapeutics: Methodology and Applications

    Science.gov (United States)

    Wei, Hui; Mo, Jingjie; Tao, Li; Russell, Reb J.; Tymiak, Adrienne A.; Chen, Guodong; Iacob, Roxana E.; Engen, John R.

    2014-01-01

    The higher order structure of protein therapeutics can be interrogated with hydrogen/deuterium exchange mass spectrometry (HDX-MS). HDX-MS is now a widely used tool in the structural characterization of protein therapeutics. In this article, HDX-MS based workflows designed for both protein therapeutic discovery and development processes are presented, focusing on the specific applications of epitope mapping for protein/drug interactions and biopharmaceutical comparability studies. Future trends in the application of HDX-MS to protein therapeutics characterization are also described. PMID:23928097

  1. Reply to "Comment on `Evidence of a first-order phase transition to metallic hydrogen' "

    Science.gov (United States)

    Silvera, Isaac F.; Zaghoo, Mohamed; Salamat, Ashkan

    2017-12-01

    Goncharov and Geballe reanalyze [Phys. Rev. B 96, 157101 (2017), 10.1103/PhysRevB.96.157101] experimental data using a finite element analysis and cannot reproduce our experimental heating curves; they use incomplete and incorrect material properties. They analyze optical data at the onset of the insulator-to-metal transition to show that it cannot be fit to a Drude model, not realizing that the Drude model does not describe metallic hydrogen in this transition region. Yet, they ignore the region where the reflectance is saturated and the data can be fit to the Drude model. They suggest that we observe semiconducting behavior rather than metallic behavior, but a straightforward calculation shows that reflectance from a semiconductor cannot explain our observed reflectance.

  2. Influence of strontium on the cubic to ordered hexagonal phase ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Oxides of the type Ba3–xSrxMgNb2O9 were synthesized by the solid state route. The x = 0 compo- sition (Ba3MgNb2O9) was found to crystallize in a disordered (cubic) perovskite structure when sintered at. 1000C. For higher Sr doping (x ≥ 0⋅5), there was clearly the presence of an ordered hexagonal phase ...

  3. A proposed model of factors influencing hydrogen fuel cell vehicle acceptance

    Science.gov (United States)

    Imanina, N. H. Noor; Kwe Lu, Tan; Fadhilah, A. R.

    2016-03-01

    Issues such as environmental problem and energy insecurity keep worsening as a result of energy use from household to huge industries including automotive industry. Recently, a new type of zero emission vehicle, hydrogen fuel cell vehicle (HFCV) has received attention. Although there are argues on the feasibility of hydrogen as the future fuel, there is another important issue, which is the acceptance of HFCV. The study of technology acceptance in the early stage is a vital key for a successful introduction and penetration of a technology. This paper proposes a model of factors influencing green vehicle acceptance, specifically HFCV. This model is built base on two technology acceptance theories and other empirical studies of vehicle acceptance. It aims to provide a base for finding the key factors influencing new sustainable energy fuelled vehicle, HFCV acceptance which is achieved by explaining intention to accept HFCV. Intention is influenced by attitude, subjective norm and perceived behavioural control from Theory of Planned Behaviour and personal norm from Norm Activation Theory. In the framework, attitude is influenced by perceptions of benefits and risks, and social trust. Perceived behavioural control is influenced by government interventions. Personal norm is influenced by outcome efficacy and problem awareness.

  4. Fiber Bragg gratings in the radiation environment: Change under the influence of radiolytic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Butov, Oleg V., E-mail: obutov@mail.ru; Golant, Konstantin M. [Kotel' nikov Institute of Radio-Engineering and Electronics of RAS, 11-7 Mokhovaya Str., Moscow 125009 (Russian Federation); Shevtsov, Igor' A.; Fedorov, Artem N. [Prolog LLC, PO Box 3007, Obninsk, the Kaluga Region 249033 (Russian Federation)

    2015-08-21

    The change of the transmission spectra of fiber Bragg gratings written in the optical fibers, whose silica cores are doped with either germanium or nitrogen, is studied experimentally under the influence of gamma-radiation. The transmission spectra in the neighborhood of the resonance (Bragg) wavelengths were regularly recorded “in-situ” in the course of irradiation during 24 days. For this purpose, uncoated gratings were placed in a pool near the spent fuel rods of a nuclear reactor. The fibers with the gratings written in them were in immediate contact with water. The estimated total absorbed radiation dose of the fibers is approximately 5 MGy. Molecular hydrogen, which is produced by radiolysis of water and penetrates into the core of silica fiber, is found to interact with the defects of Ge-doped silica induced by gamma-radiation, thereby causing a strong impact on the parameters of the spectrum of the Bragg gratings. On the contrary, in the case of gratings inscribed in N-doped silica fibers, the hydrogen molecules interact with defects induced in the course of laser UV exposure during the grating writing only. The possible subsequent formation of additional defects in N-doped silica under the influence of gamma-radiation has no substantial impact on the transmission spectra of Bragg gratings, which remained stable. The obtained results suggest that a small amount of molecular hydrogen resided in the fiber core is the main source of radiation instability of Ge-doped fiber Bragg grating sensors in radiation environments. These hydrogen molecules can remain in the Bragg gratings, in particular, after the inscription process in the hydrogen-loaded fibers.

  5. Influence of high flux hydrogen-plasma exposure on the thermal shock induced crack formation in tungsten

    NARCIS (Netherlands)

    Wirtz, M.; Linke, J.; Pintsuk, G.; Rapp, J.; Wright, G. M.

    2012-01-01

    The influence of high flux hydrogen-plasma on the thermal shock behaviour of tungsten was investigated in a combined experiment using the linear plasma device Pilot-PSI and the electron beam facility JUDITH 1. Tungsten targets were exposed to high flux hydrogen plasma, cyclic thermal shock tests and

  6. The influence of hydrogen on the chemical, mechanical, optical/electronic, and electrical transport properties of amorphous hydrogenated boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Nordell, Bradley J.; Karki, Sudarshan; Nguyen, Thuong D.; Rulis, Paul; Caruso, A. N.; Paquette, Michelle M., E-mail: paquettem@umkc.edu [Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, Missouri 64110 (United States); Purohit, Sudhaunshu S. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri 64110 (United States); Li, Han; King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Dutta, Dhanadeep; Gidley, David [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Lanford, William A. [Department of Physics, University at Albany, Albany, New York 12222 (United States)

    2015-07-21

    structural disorder. All of these correlations in a-B{sub x}C:H{sub y} are found to be very similar to those observed in amorphous hydrogenated silicon (a-Si:H), which suggests parallels between the influence of hydrogenation on their material properties and possible avenues for optimization. Finally, an increase in electrical resistivity with increasing H at <35 at. % H concentration is explained, not by disorder as in a-Si:H, but rather by a lower rate of hopping associated with a lower density of sites, assuming a variable range hopping mechanism interpreted in the framework of percolation theory.

  7. Influence of hydrogen bond accepting ability of anions on the adsorption performance of ionic liquid surface molecularly imprinted polymers.

    Science.gov (United States)

    Zhu, Guifen; Gao, Xia; Wang, Xiaolong; Wang, Jianji; Fan, Jing

    2018-01-12

    To illuminate the influence mechanism of anionic structure of ionic liquids (ILs) on the adsorption performance of surface molecularly imprinted polymers (MIPs), in this work, six newly designed MIPs were prepared on the surface of amino-poly(styrene-divinylbenzene) particles by using imidazolium ILs with the same cation [C 4 mim] + but different anions (Cl, CH 3 SO 3 , PF 6 , BF 4 , C 4 F 7 O 2 , C 4 F 9 SO 3 ) as template molecules, methacrylic acid as functional monomer, and ethylene dimethacrylate as cross-linker. The resulting MIP materials were characterized by IR and SEM, and the influence of hydrogen bond accepting ability of anions on the adsorption performance of the MIPs for the ILs was investigated in acetonitrile. It was found that adsorption capacity of the MIPs towards the ILs decreased in the order MIP [C4mim][Cl]  > MIP [C4mim][C4F7O2]  ≥ MIP [C4mim][BF4] and MIP [C4mim][CH3SO3]  > MIP [C4mim][C4F9SO3]  > MIP [C4mim][PF6] , which is in good agreement with the ability of anions of the ILs to form hydrogen bonds. Ultraviolet, 1 H-NMR and 35 Cl-NMR spectroscopy was then used to study the interactions of anions of the ILs with the functional monomer. It was found that the hydrogen bond interaction between anions of the ILs and acidic proton of the functional monomer was the main driving force for the high adsorption selectivity of the imprinted polymers, and the stronger hydrogen bond interaction indicates higher binding capacity and higher selectivity of the polymers towards the ILs. It was also verified that the ILs with stronger hydrogen bond accepting ability of anions could be selectively extracted by the corresponding IL-MIPs. These results may provide new insight into the recognition mechanism of MIPs for ILs, and are also useful for the rational design of this new class of imprinting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Influence of hydrogen temperature on the stability of a rocket engine combustor operated with hydrogen and oxygen

    Science.gov (United States)

    Gröning, Stefan; Hardi, Justin; Suslov, Dmitry; Oschwald, Michael

    2017-03-01

    Since the late 1960s, low hydrogen injection temperature is known to have a destabilising effect on rocket engines with the propellant combination hydrogen/oxygen. Self-excited combustion instabilities of the first tangential mode have been found recently in a research rocket combustor operated with the propellant combination hydrogen/oxygen with a hydrogen temperature of 95 K. A hydrogen temperature ramping experiment has been performed with this research combustor to analyse the impact of hydrogen temperature on the self-excited combustion instabilities. The temperature was varied between 40 and 135 K. Contrary to past results found in literature, the combustor was found to be stable at low hydrogen temperatures while increased oscillation amplitudes of the first tangential mode were found at higher temperatures of around 100 K and above, which is consistent with previous observations of instabilities in this combustor. Further analysis shows that hydrogen temperature has a strong impact on the combustion chamber resonance frequencies. By varying the hydrogen injection temperature, the frequency of the first tangential mode is shifted to coincide with the second longitudinal resonance frequency of the liquid oxygen injector. Excitation of combustion chamber pressure oscillations was observed during such events.

  9. Biofuel and Hydrogen Influence for Operation Parameters of Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Martynas Damaševičius

    2016-12-01

    Full Text Available Paper presents research of efficient and ecological parameters of gasoline engine working with biobuthanol (10% and 20% by volume and addi-tionaly supplying oxygen and hydrogen (HHO gas mixture (3.6 l/min, which was obtained from from water by electrolysis. Biobuthanol addition decreases rate of heat release, the combustion temperature and pressure are lower, which has an influence on lower nitrous oxide (NOx emission in exhaust gases. However, biobuthanol increases carbon monoxide (CO concentration. Biobuthanol fuel has a simplier molecular structure, therefore the concentration of HC in the exhaust gas is decreasing. Due to lower heating value of biobuthanol fuel and slower combustion process, the engine efficiency decreases and specific fuel consumptions increase. The change of engine energetical indicators due to biobuthanol, can be compensated with advanced ignition angle. Using experimental investigation, it was determined, that negative biobuthanol influence for the combustion process and engine efficient inicators can be compensated also by additional supplied HHO gas, in which the hydrogen element iprove fuel mixture com-bustion. Fuel combustion process analysis was carried out using AVL BOOST software. Experimental research and combustion process numerical simulation showed that using balanced biobuthanol and hydrogen addition, optimal efficient and ecological parameters could be achieved, when engine is working for petrol fuel typical optimal spark timing.

  10. Influence of fuel temperature on supersonic mixing and combustion of hydrogen

    Science.gov (United States)

    Rogers, R. C.

    1977-01-01

    Results are presented from an experimental investigation of the influence of fuel stagnation temperature on the mixing and reaction of hydrogen injected transverse to a supersonic flow in a duct. The hydrogen fuel was injected stoichiometrically at stagnation temperatures of 300 K and 800 K from a row of five circular orifices in the duct wall. Detailed measurements in the flow at the duct exit are used to determine the overall amount of mixing accomplished at each of three test conditions. Static pressure distributions are used with duct wall temperatures and heat flux in a one-dimensional analysis to deduce the fraction of fuel reacted along the duct. Results from the one-dimensional analyses of the tests with hot fuel indicated slightly more fuel reacted at the exit; however, differences in the accomplished mixing obtained from integrations of exit surveys were small.

  11. Influence of Hydrogen-Based Storage Systems on Self-Consumption and Self-Sufficiency of Residential Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Christian Pötzinger

    2015-08-01

    Full Text Available This paper analyzes the behavior of residential solar-powered electrical energy storage systems. For this purpose, a simulation model based on MATLAB/Simulink is developed. Investigating both short-time and seasonal hydrogen-based storage systems, simulations on the basis of real weather data are processed on a timescale of 15 min for a consideration period of 3 years. A sensitivity analysis is conducted in order to identify the most important system parameters concerning the proportion of consumption and the degree of self-sufficiency. Therefore, the influences of storage capacity and of storage efficiencies are discussed. A short-time storage system can increase the proportion of consumption by up to 35 percentage points compared to a self-consumption system without storage. However, the seasonal storing system uses almost the entire energy produced by the photovoltaic (PV system (nearly 100% self-consumption. Thereby, the energy drawn from the grid can be reduced and a degree of self-sufficiency of about 90% is achieved. Based on these findings, some scenarios to reach self-sufficiency are analyzed. The results show that full self-sufficiency will be possible with a seasonal hydrogen-based storage system if PV area and initial storage level are appropriate.

  12. Influence of heat transfer rates on pressurization of liquid/slush hydrogen propellant tanks

    Science.gov (United States)

    Sasmal, G. P.; Hochstein, J. I.; Hardy, T. L.

    1993-01-01

    A multi-dimensional computational model of the pressurization process in liquid/slush hydrogen tank is developed and used to study the influence of heat flux rates at the ullage boundaries on the process. The new model computes these rates and performs an energy balance for the tank wall whereas previous multi-dimensional models required a priori specification of the boundary heat flux rates. Analyses of both liquid hydrogen and slush hydrogen pressurization were performed to expose differences between the two processes. Graphical displays are presented to establish the dependence of pressurization time, pressurant mass required, and other parameters of interest on ullage boundary heat flux rates and pressurant mass flow rate. Detailed velocity fields and temperature distributions are presented for selected cases to further illuminate the details of the pressurization process. It is demonstrated that ullage boundary heat flux rates do significantly effect the pressurization process and that minimizing heat loss from the ullage and maximizing pressurant flow rate minimizes the mass of pressurant gas required to pressurize the tank. It is further demonstrated that proper dimensionless scaling of pressure and time permit all the pressure histories examined during this study to be displayed as a single curve.

  13. Influence of hydrogen peroxide bleaching gels on color, opacity, and fluorescence of composite resins.

    Science.gov (United States)

    Torres, C R G; Ribeiro, C F; Bresciani, E; Borges, A B

    2012-01-01

    The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (ptherapies (phydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (ptherapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

  14. Influence of hydrogen peroxide in drinking water on diazepam pharmacokinetics in chicks

    Directory of Open Access Journals (Sweden)

    Yaareb J. Mousa

    Full Text Available Aim: Stressful conditions affect drug pharmacokinetics and pharmacodynamics. This study examines the effect of hydrogen peroxide (H2O2 in drinking water on the pharmacokinetics of diazepam in a chick model of oxidative stress. Materials and Methods: Day old chicks were either provided with plane tap water (control group or H2O2 in tap water as 0.5% v/v drinking solution for two weeks in order to produce oxidative stress. On treatment days 7–14, the chicks were treated with a sedative dose of diazepam at 10 mg/kg, intramuscularly. Blood samples were obtained from chicks (5/each sampling time at times of between 0.17 to 4 h. The concentrations of diazepam in the plasma were determined by an HPLC method with UV-detector. Pharmacokinetic parameters of diazepam were calculated from the mean drug concentrations in the plasma by a non-compartmental analysis using a Windows-based computer program. Results: Injection of diazepam resulted in the appearance of the drug in the plasma of control and H2O2 -treated chicks at mean concentrations ranging between 0.11 to 0.444 and 0.131 to 0.535 μg/ml, respectively when measured between 0.17 to 4 h after administration. Diazepam concentrations of the H O -treated chicks were significantly higher than those of the control group at the sampling times 0.5, 0.75, 1 and 4 h. The highest concentration of diazepam in the plasma of both the control and H2O2 treated chicks occurred one h after the injection. The elimination half-life, mean residence time, maximum plasma concentration, area under the moment curve and area under plasma concentration-time curve in the H2O2 -treated chicks were higher than those of the control group by 35, 28, 23, 91 and 49%, respectively. Correspondingly, the steady state volume of distribution, elimination rate constant and total body clearance in the H2O2 -treated chicks decreased from those of the respective control values by 15, 24 and 33%. Conclusion: The data suggest that oral

  15. Sleep inertia, sleep homeostatic, and circadian influences on higher-order cognitive functions

    OpenAIRE

    Burke, Tina M.; Scheer, Frank A. J. L.; Ronda, Joseph M.; Czeisler, Charles A.; Wright, Kenneth P.

    2015-01-01

    Sleep inertia, sleep homeostatic, and circadian processes modulate cognition, including reaction time, memory, mood, and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-daylong study that included two 14-daylong 28h forced desynchrony protocols, to examine separate and interacting influences of sleep inertia, sleep homeostasis, and circadian phase on higher-order cognitive functions of inhibitory control and selectiv...

  16. Supported noble metals on hydrogen-treated TiO2 nanotube arrays as highly ordered electrodes for fuel cells.

    Science.gov (United States)

    Zhang, Changkun; Yu, Hongmei; Li, Yongkun; Gao, Yuan; Zhao, Yun; Song, Wei; Shao, Zhigang; Yi, Baolian

    2013-04-01

    Hydrogen-treated TiO2 nanotube (H-TNT) arrays serve as highly ordered nanostructured electrode supports, which are able to significantly improve the electrochemical performance and durability of fuel cells. The electrical conductivity of H-TNTs increases by approximately one order of magnitude in comparison to air-treated TNTs. The increase in the number of oxygen vacancies and hydroxyl groups on the H-TNTs help to anchor a greater number of Pt atoms during Pt electrodeposition. The H-TNTs are pretreated by using a successive ion adsorption and reaction (SIAR) method that enhances the loading and dispersion of Pt catalysts when electrodeposited. In the SIAR method a Pd activator can be used to provide uniform nucleation sites for Pt and leads to increased Pt loading on the H-TNTs. Furthermore, fabricated Pt nanoparticles with a diameter of 3.4 nm are located uniformly around the pretreated H-TNT support. The as-prepared and highly ordered electrodes exhibit excellent stability during accelerated durability tests, particularly for the H-TNT-loaded Pt catalysts that have been annealed in ultrahigh purity H2 for a second time. There is minimal decrease in the electrochemical surface area of the as-prepared electrode after 1000 cycles compared to a 68 % decrease for the commercial JM 20 % Pt/C electrode after 800 cycles. X-ray photoelectron spectroscopy shows that after the H-TNT-loaded Pt catalysts are annealed in H2 for the second time, the strong metal-support interaction between the H-TNTs and the Pt catalysts enhances the electrochemical stability of the electrodes. Fuel-cell testing shows that the power density reaches a maximum of 500 mWcm(-2) when this highly ordered electrode is used as the anode. When used as the cathode in a fuel cell with extra-low Pt loading, the new electrode generates a specific power density of 2.68 kWg(Pt) (-1) . It is indicated that H-TNT arrays, which have highly ordered nanostructures, could be used as ordered electrode supports

  17. Food ordering for children in restaurants: multiple sources of influence on decision making

    Science.gov (United States)

    Castro, Iana A; Williams, Christine B; Madanat, Hala; Pickrel, Julie L; Jun, Hee-Jin; Zive, Michelle; Gahagan, Sheila; Ayala, Guadalupe X

    2017-01-01

    Objective Restaurants are playing an increasingly important role in children’s dietary intake. Interventions to promote healthy ordering in restaurants have primarily targeted adults. Much remains unknown about how to influence ordering for and by children. Using an ecological lens, the present study sought to identify sources of influence on ordering behaviour for and by children in restaurants. Design A mixed-methods study was conducted using unobtrusive observations of dining parties with children and post-order interviews. Observational data included: child’s gender, person ordering for the child and server interactions with the dining party. Interview data included: child’s age, restaurant visit frequency, timing of child’s decision making, and factors influencing decision making. Setting Ten independent, table-service restaurants in San Diego, CA, USA participated. Subjects Complete observational and interview data were obtained from 102 dining parties with 150 children (aged 3–14 years). Results Taste preferences, family influences and menus impacted ordering. However, most children knew what they intended to order before arriving at the restaurant, especially if they dined there at least monthly. Furthermore, about one-third of children shared their meals with others and all shared meals were ordered from adult (v. children’s) menus. Parents placed most orders, although parental involvement in ordering was less frequent with older children. Servers interacted frequently with children but generally did not recommend menu items or prompt use of the children’s menu. Conclusions Interventions to promote healthy ordering should consider the multiple sources of influence that are operating when ordering for and by children in restaurants. PMID:27334904

  18. First-principles study of the interactions of hydrogen with low-index surfaces of PdCu ordered alloy

    Directory of Open Access Journals (Sweden)

    Min Tang

    2017-12-01

    Full Text Available PdCu catalysts play a key role in several hydrogen-involved processes. Among these reactions, the interaction of hydrogen with PdCu essentially determines the catalytic performance. However, the response of PdCu to surrounding hydrogen has been poorly investigated, especially for specific facets of PdCu at different environment. In this work, taking temperature and hydrogen pressure into account, we studied the hydrogen-surface interactions for four low-index surfaces of PdCu through first-principles calculations. It was found that H-PdCu adsorption strong relies on the facets, hydrogen coverage, and reaction environment (temperature and H-pressure. Our work highlights the importance of the environment on the nature of catalyst surfaces and reactions and offers a plausible way to investigate the interactions between gas and the surfaces of nanocatalysts in real reactions.

  19. Multiferroic behavior associated with an order-disorder hydrogen bonding transition in metal-organic frameworks (MOFs) with the perovskite ABX3 architecture.

    Science.gov (United States)

    Jain, Prashant; Ramachandran, Vasanth; Clark, Ronald J; Zhou, Hai Dong; Toby, Brian H; Dalal, Naresh S; Kroto, Harold W; Cheetham, Anthony K

    2009-09-30

    Multiferroic behavior in perovskite-related metal-organic frameworks of general formula [(CH(3))(2)NH(2)]M(HCOO)(3), where M = Mn, Fe, Co, and Ni, is reported. All four compounds exhibit paraelectric-antiferroelectric phase transition behavior in the temperature range 160-185 K (Mn: 185 K, Fe: 160 K; Co: 165 K; Ni: 180 K); this is associated with an order-disorder transition involving the hydrogen bonded dimethylammonium cations. On further cooling, the compounds become canted weak ferromagnets below 40 K. This research opens up a new class of multiferroics in which the electrical ordering is achieved by means of hydrogen bonding.

  20. Influence of temperature on hydrogen production from bread mill wastewater by sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Tang, G.L.; Huang, J.; Li, Y.Y.; Sun, Z.J. [China Agricultural Univ., Beijing (China). College of Resources and Environmental Sciences; Tang, Q.Q. [Nanjing Univ., Nanjing (China). Medical School

    2008-07-01

    Hydrogen (H{sub 2}) energy has been touted as a sustainable and clean energy source that can solve environmental problems such as acid rain, greenhouse gases and transboundary pollution. While most hydrogen is currently produced from nonrenewable sources such as oil, natural gas, and coal, these processes are energy-intensive and costly. The biological production of hydrogen using fermentative bacteria is an environmentally friendly and energy-saving process which has recently attracted much attention as an effective way of converting biomass into H{sub 2}. Waste-based H{sub 2} production processes mainly include wastewater from paper mills, municipal solid waste, rice winery wastewater, and food wastewater from cafeterias. This study investigated the use of bread mill wastewater for biological production of hydrogen due to its high production potential. Annual bread production in China is estimated to be over 1.5 million tons, producing 10 m{sup 3} of wastewater per ton of bread. The wastewater has high chemical oxygen demand and carbohydrate concentrations and is therefore suitable for anaerobic treatment processes. This study evaluated the effect of temperature on H{sub 2} production from bread mill wastewater by sewage sludge in lab-scale experiments. H{sub 2} production, the distribution of volatile fatty acids and the lag-phase time were influenced by temperature. H{sub 2} production and H{sub 2} yield increased with increasing temperature. The optimal temperature for H{sub 2} production was 50 degrees C. Butyrate, acetate and alcohol were the main by-products of H{sub 2} fermentation. According to 16S rDNA analysis, the dominant microflora was Clostridium, but the microbial species varied with temperature. The activation energy for H{sub 2} production was estimated to be 92 kJ per mol for bread mill wastewater. It was concluded that bread mill wastewater could potentially serve as a substrate for H{sub 2} production. This research provides a means of

  1. The influence of rearing order on personality development within two adoption cohorts.

    Science.gov (United States)

    Beer, J M; Horn, J M

    2000-08-01

    There is an extensive literature on the relationship between birth order and psychological traits, but no previous study has investigated the influence of ordinal position on personality development within adoptive siblings. Such a design is important because it effectively separates the effects of biological birth order and rearing order. Here we report data from two adoption cohorts in which subjects were biological first-borns reared in various ordinal positions. Data were analyzed with reference to Sulloway's (1996) evolutionarily based sibling rivalry theory of birth order effects. Between- and within-family analyses indicated that rearing order's influence on personality was very weak. The only clear difference was for conscientiousness, on which first-reared siblings scored higher. We draw possible implications for Sulloway's theory and speculate upon an alternative, prenatal biological process that may produce birth order differences.

  2. Diffusion of Hydrogen in Proton Implanted Silicon: Dependence on the Hydrogen Concentration

    CERN Document Server

    Faccinelli, Martin; Jelinek, Moriz; Wuebben, Thomas; Laven, Johannes G; Schulze, Hans-Joachim; Hadley, Peter

    2016-01-01

    The reported diffusion constants for hydrogen in silicon vary over six orders of magnitude. This spread in measured values is caused by the different concentrations of defects in the silicon that has been studied. Hydrogen diffusion is slowed down as it interacts with impurities. By changing the material properties such as the crystallinity, doping type and impurity concentrations, the diffusivity of hydrogen can be changed by several orders of magnitude. In this study the influence of the hydrogen concentration on the temperature dependence of the diffusion in high energy proton implanted silicon is investigated. We show that the Arrhenius parameters, which describe this temperature dependence decrease with increasing hydrogen concentration. We propose a model where the relevant defects that mediate hydrogen diffusion become saturated with hydrogen at high concentrations. When the defects that provide hydrogen with the lowest energy positions in the lattice are saturated, hydrogen resides at energetically le...

  3. Hydrogen-induced stress relaxation in thin Pd films: influence of carbon implementation.

    Science.gov (United States)

    Nowakowski, Robert; Grzeszczak, Patrycja; Dus, Ryszard

    2007-02-13

    The influence of carbon impurities on mechanical properties of thin Pd film in the process of hydride formation and its disintegration has been investigated "in situ" by means of atomic force microscopy (AFM). Pd interaction with hydrogen leads to the formation of hydride PdHx, if critical conditions of pressure and temperature are reached (equilibrium hydrogen pressure over PdHx at 298 K is approximately 1 kPa). The lattice constant of PdHx is larger than that of the original metal, and the hydride formation generates high stress within the film. As a consequence, the reversible formation of well organized mesoscopic protrusions on the film surface is observed. In this paper, we focus our investigation on the mechanical response which occurs when, prior to hydride generation, carbon atoms are incorporated into the bulk of the film. The systems characterized by carbon incorporation from the two opposite sides of thin palladium film (HOPG substrate and hydrocarbon fragments deposit from a gas-phase reached by preadsorption of ethylene) are compared. For both cases the mechanism of mechanical response is the same, but very different from that registered for pure thin palladium film. Carbon impurities induce, during PdHx decomposition, creation of an organized network of cracks which divides the continuous film into separated domains. The mechanisms of carbon introduction occurring in both cases have been proposed.

  4. Influences of environmental and operational factors on dark fermentative hydrogen production: a review

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Parviz [Department of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur (Malaysia); Department of Environmental Health Engineering, Faculty of Health, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Ibrahim, Shaliza; Ghafari, Shahin [Department of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur (Malaysia); Annuar, Mohamad Suffian Mohamad; Vikineswary, Sabaratnam [Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur (Malaysia); Zinatizadeh, Ali Akbar [Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Water and Wastewater Research Center (WWRC), Razi University, Kermanshah (Iran, Islamic Republic of)

    2012-11-15

    Hydrogen (H{sub 2}) is one of renewable energy sources known for its non-polluting and environmentally friendly nature, as its end combustion product is water (H{sub 2}O). The biological production of H{sub 2} is a less energy intensive alternative where processes can be operated at ambient temperature and pressure. Dark fermentation by bacterial biomass is one of multitude of approaches to produce hydrogen which is known as the cleanest renewable energy and is thus receiving increasing attention worldwide. The present study briefly reviews the biohydrogen production process with special attention on the effects of several environmental and operational factors towards the process. Factors such as organic loading rate, hydraulic retention time, temperature, and pH studied in published reports were compared and their influences are discussed in this work. This review highlights the variations in examined operating ranges for the factors as well as their reported optimum values. Divergent values observed for the environmental/operational factors merit further exploration in this field. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Influence of plastic strain on the hydrogen evolution reaction on nickel (100) single crystal surfaces to improve hydrogen embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Lekbir, C., E-mail: choukri.lekbir@univ-lr.fr; Creus, J.; Sabot, R.; Feaugas, X.

    2013-08-20

    Hydrogen-induced embrittlement can be accountable for premature failure of structure in relation with physical and/or chemical processes occurring on material's surface or in the bulk of the material. Hydrogen Evolution Reaction (HER) corresponding to the early step of hydrogen ingress in the material is explored in present study in relation with plastic strain. HER on nickel (100) single crystal in sulphuric acid medium can be related by a Volmer–Heyrovsky mechanism. The corresponding elementary kinetic parameters as symmetry coefficients, activation enthalpies, and number of active sites have been identified via a thermokinetic model using experimental data. These parameters can be affected by defects associated with plastic strain. Irreversible plastic strain modifies the density and the distribution of storage dislocations affecting the surface roughness at atomic scale and generating additional active adsorption sites. Furthermore, surface emergence of mobile dislocations induces the formation of slip bands, which modify the surface roughness and the electronic state of the surface and increases the (111) surface density. The consequence of plastic strain on HER is explored and discussed in relation with both processes.

  6. Facile Fabrication of Composition-Tuned Ru-Ni Bimetallics in Ordered Mesoporous Carbon for Levulinic Acid Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying; Gao, Guang; Zhang, Xin; Li, Fuwei [ChinaU - Petroleum; (Chinese Aca. Sci.)

    2016-02-04

    Bimetallic catalysts are of great importance due to their unique catalytic properties. However, their conventional synthesis requires tedious multistep procedures and prolonged synthetic time, and the resulting bimetallics usually disperse unevenly and show poor stability. It is challenging to develop a facile and step-economic synthetic methodology for highly efficient bimetallic catalysts. In this study, we report an elegant metal complex-involved multicomponent assembly route to highly efficient Ru–Ni bimetallics in ordered mesoporous carbons (OMC). The fabrication of composition-tuned Ru–Ni bimetallics in OMC (RuxNi1–x–OMC, x = 0.5–0.9) was facilely realized via in situ construction of CTAB-directed cubic Ia3d chitosan-ruthenium–nickel–silica mesophase before pyrolysis and silica removal. The resulting RuxNi1–x–OMC materials are in-depth characterized with X-ray diffraction, N2 adsorption–desorption, transmission electron microscopy, infrared spectrum, and X-ray absorption fine structure. This facile fabrication method renders homogeneously dispersed Ru–Ni bimetallics embedded in the mesoporous carbonaceous framework and creates a highly active and stable Ru0.9Ni0.1–OMC catalyst for the hydrogenation of levulinic acid (LA) to prepare γ-valerolactone (GVL), a biomass-derived platform molecule with wide application in the preparation of renewable chemicals and liquid transportation fuels. A high TOF (>2000 h–1) was obtained, and the Ru0.9Ni0.1–OMC catalyst could be used at least 15 times without obvious loss of its catalytic performance.

  7. Fracture Analysis of Rubber Sealing Material for High Pressure Hydrogen Vessel

    National Research Council Canada - National Science Library

    YAMABE, Junichiro; FUJIWARA, Hirotada; NISHIMURA, Shin

    2011-01-01

    In order to clarify the influence of high pressure hydrogen gas on mechanical damage in a rubber O-ring, the fracture analysis of the O-ring used for a sealing material of a pressure hydrogen vessel was conducted...

  8. On the influence of hydronium and hydroxide ion diffusion on the hydrogen and oxygen evolution reactions in aqueous media

    DEFF Research Database (Denmark)

    Wiberg, Gustav Karl Henrik; Arenz, Matthias

    2015-01-01

    We present a study concerning the influence of the diffusion of H+ and OH- ions on the hydrogen and oxygen evolution reactions (HER and OER) in aqueous electrolyte solutions. Using a rotating disk electrode (RDE), it is shown that at certain conditions the observed current, i.e., the reaction rate...

  9. Formation and annihilation of E4 centers in ZnO: Influence of hydrogen

    Science.gov (United States)

    Hupfer, A.; Bhoodoo, C.; Vines, L.; Svensson, B. G.

    2016-05-01

    Hydrothermally grown n-type ZnO bulk samples have been implanted with protons and deuterium ions to fluences in the range of 8 × 1010 to 8 × 1011 cm-2. The implantations were performed at the temperature of 285 K, and the samples were then analyzed in-situ by deep level transient spectroscopy (DLTS) using a setup connected to the implanter beam line. The concentration of the so-called E4 center, having an apparent energy level at ˜0.57 eV below the conduction edge, is found to increase linearly with the ion fluence and the generation rate is proportional to the elastic energy deposition, as expected for a primary defect. Isothermal annealing of the E4 center at temperatures between 290 and 315 K reveals first-order kinetics with the activation energy of ˜0.6 eV. The annealing rate is strongly enhanced with increasing hydrogen fluence, and a model invoking migration of interstitial hydrogen and subsequent reaction with E4 exhibits close agreement with the experimental data. The rate of electron capture by E4 during the DLTS filling pulse depends on temperature, and it displays a thermal barrier of ˜0.15 eV. Most of these experimental results for E4 conform to the theoretically predicted properties of the oxygen vacancy (VO) and a tentative assignment of E4 to VO is made, corroborating previous suggestions in the literature. In particular, the 0.57 eV level is ascribed to the double donor state of VO.

  10. Formation and annihilation of E4 centers in ZnO: Influence of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Hupfer, A.; Bhoodoo, C.; Vines, L.; Svensson, B. G. [Physics Department/Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, Oslo N-0316 (Norway)

    2016-05-14

    Hydrothermally grown n-type ZnO bulk samples have been implanted with protons and deuterium ions to fluences in the range of 8 × 10{sup 10} to 8 × 10{sup 11 }cm{sup −2}. The implantations were performed at the temperature of 285 K, and the samples were then analyzed in-situ by deep level transient spectroscopy (DLTS) using a setup connected to the implanter beam line. The concentration of the so-called E4 center, having an apparent energy level at ∼0.57 eV below the conduction edge, is found to increase linearly with the ion fluence and the generation rate is proportional to the elastic energy deposition, as expected for a primary defect. Isothermal annealing of the E4 center at temperatures between 290 and 315 K reveals first-order kinetics with the activation energy of ∼0.6 eV. The annealing rate is strongly enhanced with increasing hydrogen fluence, and a model invoking migration of interstitial hydrogen and subsequent reaction with E4 exhibits close agreement with the experimental data. The rate of electron capture by E4 during the DLTS filling pulse depends on temperature, and it displays a thermal barrier of ∼0.15 eV. Most of these experimental results for E4 conform to the theoretically predicted properties of the oxygen vacancy (V{sub O}) and a tentative assignment of E4 to V{sub O} is made, corroborating previous suggestions in the literature. In particular, the 0.57 eV level is ascribed to the double donor state of V{sub O}.

  11. Assessing the influence of registered dietitian order-writing privileges on parenteral nutrition use.

    Science.gov (United States)

    Peterson, Sarah J; Chen, Yimin; Sullivan, Cheryl A; Kinnare, Kelly F; Tupesis, Nicole C; Patel, Gourang P; Sowa, Diane C; Lateef, Omar; Sheean, Patricia M

    2010-11-01

    Previous studies have examined the influence of a nutrition support team on parenteral nutrition (PN) use; however, the influence of registered dietitian (RD) order-writing privileges on appropriate PN use has yet to be reported. A retrospective cohort was conducted at a single tertiary care urban academic medical center to compare adult PN use before RD order-writing privileges (January 1, 2003 to December 31, 2004, pre-privileges) to after RD order-writing privileges (January 1, 2006 to December 31, 2007, post-privileges). RD order-writing privileges were obtained June 2005; PN patients during the washout period (January 1, 2005 to December 31, 2005) were not included. Descriptive statistics were conducted (N=1,965 patients). Although total hospital admissions increased from the pre-privileges to post-privileges periods (Ppoor oral intake (130 to 41 patients), pancreatitis (78 to 26 patients), intractable nausea and vomiting (68 to 23 patients), and mucositis (56 to 18 patients; all Pswriting privileges can decrease inappropriate PN use and costs in a hospital setting. Future studies should continue to highlight the influence of RDs in these advanced practice roles, as well as other members of the nutrition support team, especially with regard to nutrition support delivery and patient outcomes. Copyright © 2010 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

  12. Influence of displacement and its first- and second-order derivative components on curvature fringe formations in speckle shearography.

    Science.gov (United States)

    Wang, Kaifu; Tieu, Anh Kiet; Li, Enbang

    2002-08-01

    The influence of displacement and its first- and second-order derivative components on curvature fringe formations in speckle shearography is discussed. The results show that (a) all the displacement components have no direct influence on curvature fringe formations; (b) only the first-order derivative component along the centerline of three apertures has an influence on curvature fringe formations, whereas all the other first-order components have no influence; and (c) all the second-order derivative components have no influence on curvature fringe formations. Results from theory and experiments are in good agreement.

  13. Influence of pressure on ion energy distribution functions in EUV-induced hydrogen plasmas

    Science.gov (United States)

    van de Ven, T. H. M.; Reefman, P.; de Meijere, C. A.; Banine, V. Y.; Beckers, J.

    2016-09-01

    Next-generation lithography tools currently use Extreme Ultraviolet (EUV) radiation to create even smaller features on computer chips. The high energy photons (92 eV) induce a plasma in the low pressure background gas by photoionization. Industries have realized that these plasmas are of significant importance with respect to machine lifetime because impacting ions affect exposed surfaces. The mass resolved ion energy distribution function (IEDF) is therefore one of the main plasma parameters of interest. In this research an ion mass spectrometer is used to investigate IEDFs of ions impacting on surfaces in EUV-induced plasmas. EUV radiation is focused into a vessel with a low pressure hydrogen environment. Here, photoionization creates free electrons with energies up to 76 eV, which further ionize the background gas. The influence of the pressure on plasma composition and IEDFs has been investigated in the range 0.1-10 Pa. In general the ion fluxes towards the surface increase with pressure. However, above 5 Pa the flux of H2+ is not affected by the increase in pressure due to the balance between the creation of H2+ and the conversion of H2+ to H3+. These results will be used to benchmark plasma scaling models and verify numerical simulations.

  14. The Influence of the Position of the Double Bond and Ring Size on the Stability of Hydrogen Bonded Complexes.

    Science.gov (United States)

    Cheng, Shumin; Tang, Shanshan; Tsona, Narcisse T; Du, Lin

    2017-09-12

    To study the influence of the position of the double bond and ring size on the stability of hydrogen bonded complexes, the 1:1 complexes formed between 2,2,2-trifluoroethanol (TFE) and three heterocyclic compounds including 2,3-dihydrofuran (2,3-DHF), 2,5-dihydrofuran (2,5-DHF) and 3,4-dihydropyran (3,4-DHP) were investigated systematically. The formation of hydrogen bonded TFE-2,3-DHF, TFE-2,5-DHF and TFE-3,4-DHP complexes were identified by gas phase FTIR spectroscopy at room temperature, and the OH-stretching fundamental transition of TFE was red shifted upon complexation. The competition between the O atom and π-electrons bonding sites within the complexes was studied, and the O-H···π type hydrogen bond was found to be less stable than the O-H···O in all three cases. The observed red shifts of the OH-stretching fundamental transitions in the complexes were attributed to the formation of O-H···O hydrogen bond. Equilibrium constants of the complexation reactions were determined from measured and calculated OH-stretching fundamental intensities. Both theoretical calculations and experimental results reveal that the hydrogen bond strengths in the complexes follow the sequence: TFE-2,5-DHF > TFE-2,3-DHF ≈ TFE-3,4-DHP, thus the position of the double bond exerts significantly larger influence than ring size on the stability of the selected hydrogen bonded complexes.

  15. Influence of storage, heat treatment, and solids composition on the bleaching of whey with hydrogen peroxide.

    Science.gov (United States)

    Li, Xiaomeng E; Campbell, Rachel E; Fox, Aaron J; Gerard, Patrick D; Drake, MaryAnne

    2012-07-01

    The residual annatto colorant in liquid whey is bleached to provide a desired neutral color in dried whey ingredients. This study evaluated the influence of starter culture, whey solids and composition, and spray drying on bleaching efficacy. Cheddar cheese whey with annatto was manufactured with starter culture or by addition of lactic acid and rennet. Pasteurized fat-separated whey was ultrafiltered (retentate) and spray dried to 34% whey protein concentrate (WPC34). Aliquots were bleached at 60 °C for 1 h (hydrogen peroxide, 250 ppm), before pasteurization, after pasteurization, after storage at 3 °C and after freezing at -20 °C. Aliquots of retentate were bleached analogously immediately and after storage at 3 or -20 °C. Freshly spray dried WPC34 was rehydrated to 9% (w/w) solids and bleached. In a final experiment, pasteurized fat-separated whey was ultrafiltered and spray dried to WPC34 and WPC80. The WPC34 and WPC80 retentates were diluted to 7 or 9% solids (w/w) and bleached at 50 °C for 1 h. Freshly spray-dried WPC34 and WPC80 were rehydrated to 9 or 12% solids and bleached. Bleaching efficacy was measured by extraction and quantification of norbixin. Each experiment was replicated 3 times. Starter culture, fat separation, or pasteurization did not impact bleaching efficacy (P > 0.05) while cold or frozen storage decreased bleaching efficacy (P whey or 34% (w/w) protein liquid retentate (P whey. Optimization of whey bleaching conditions is important to reduce the negative effects of bleaching on the flavor of dried whey ingredients. This study established that liquid storage and whey composition are critical processing points that influence bleaching efficacy. © 2012 Institute of Food Technologists®

  16. Influence of salinity on hydrogen isotope fractionation in Rhizophora mangroves from Micronesia

    Science.gov (United States)

    Ladd, S. Nemiah; Sachs, Julian P.

    2015-11-01

    Hydrogen isotope ratios (2H/1H or δ2H) of plant leaf waxes typically covary with those of precipitation, and are therefore used as a proxy for past hydrologic variability. Mangroves present an important exception to this relationship, as salinity can strongly influence 2H fractionation in leaf lipids. To better understand and calibrate this effect, δ2H values of taraxerol and n-alkanes were measured in the leaves of Rhizophora spp. (red mangroves) from three estuaries and four brackish lakes on the Micronesian islands of Pohnpei and Palau, and compared to the δ2H and δ18O values of leaf water, xylem water and surface water. Net 2H discrimination between surface water and taraxerol increased by 0.9 ± 0.2‰ per part per thousand (ppt-1) over a salinity range of 1-34 ppt. Xylem water was always depleted in 2H relative to surface water, and the magnitude of this depletion increased with salinity, which is most likely due to a combination of greater 2H discrimination by roots during water uptake and opportunistic use of freshwater. Changes in the 2H content of xylem water can account for up to 43% of the change in net taraxerol fractionation with salinity. Leaf water isotopes were minimally enriched relative to xylem water and there was not significant variability in leaf water enrichment with salinity, which is consistent with a Péclet-modified Craig-Gordon model of leaf water enrichment. As leaf water enrichment is therefore unlikely to be responsible for increased 2H/1H fractionation in mangrove leaf lipids at elevated salinities, the majority of this signal is most likely explained either by changes in biosynthetic fractionation in response to salt stress or by salinity influenced changes in the timing of water uptake and lipid synthesis.

  17. Influence of cosmetically tinted soft contact lenses on higher-order wavefront aberrations and visual performance.

    Science.gov (United States)

    Hiraoka, Takahiro; Ishii, Yuko; Okamoto, Fumiki; Oshika, Tetsuro

    2009-02-01

    To investigate the influence of cosmetically tinted soft contact lenses on ocular higher-order aberrations and visual performance, and to analyze the relationship between these parameters after the lens wear. In 44 eyes of 22 subjects, visual acuity, contrast sensitivity under photopic and mesopic conditions, and ocular higher-order aberrations were evaluated before and after wearing the tinted soft contact lenses (1-day Acuvue Colours; Vistakon, Jacksonville, FL). Contrast sensitivity under a photopic condition was determined at 3, 6, 12, and 18 cycles per degree, and the area under the log contrast sensitivity function (AULCSF) was calculated. Mesopic contrast sensitivity with and without glare was assessed. Ocular higher-order aberrations for a 4-mm pupil were measured, and coma-like, spherical-like, and total higher-order aberrations were determined. The tinted contact lens wearing resulted in significant decreases in log contrast sensitivity at all spatial frequencies (P 0.05), the changes in total higher-order aberrations showed a significant correlation with those in AULCSF (P 0.05). Cosmetically tinted contact lenses increase ocular higher-order aberrations and worsen contrast sensitivity under both photopic and mesopic conditions. Increases in higher-order aberrations are responsible for decreased contrast sensitivity under the photopic condition. Tinted contact lens wearers should be sufficiently informed about the possible reduction in optical quality of the eye and quality of vision.

  18. Mechanisms of hydrogen bond formation between ionic liquids and cellulose and the influence of water content.

    Science.gov (United States)

    Rabideau, Brooks D; Ismail, Ahmed E

    2015-02-28

    We study the dynamics of the formation of multiple hydrogen bonds between ionic liquid anions and cellulose using molecular dynamics simulations. We examine fifteen different ionic liquids composed of 1-alkyl-3-methylimidazolium cations ([Cnmim], n = 1, 2, 3, 4, 5) paired with either chloride, acetate or dimethylphosphate. We map the transitions of anions hydrogen bonded to cellulose into different bonding states. We find that increased tail length in the ionic liquids has only a very minor effect on these transitions, tending to slow the dynamics of the transitions and increasing the hydrogen bond lifetimes. Each anion can form up to four hydrogen bonds with cellulose. We find that this hydrogen bond "redundancy" leads to multiply bonded anions having lifetimes three to four times that of singly bound anions. Such redundant hydrogen bonds account for roughly half of all anion-cellulose hydrogen bonds. Additional simulations for [C2mim]Cl, [C2mim]Ac and [C2mim]DMP were performed at different water concentrations between 70 mol% and 90 mol%. It was found that water crowds the hydrogen bond-accepting sites of the anions, preventing interactions with cellulose. The more water that is present in the system, the more crowded these sites become. Thus, if a hydrogen bond between an anion and cellulose breaks, the likelihood that it will be replaced by a nearby water molecule increases as well. We show that the formation of these "redundant" hydrogen bonding states is greatly affected by the presence of water, leading to steep drops in hydrogen bonding between the anions and cellulose.

  19. Raman Study of the Influence of Hydrogen on Defects in ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Exarhos, Gregory J.; Yao, Chunhua; Wang, Li Q.

    2007-06-15

    Raman spectra of ZnO powders and thin films obtained during exposure to hydrogen at different concentrations, temperatures, and electrochemical conditions indicated two distinct effects of hydrogen on the defect structure of the oxide. At lower concentrations of hydrogen in a gaseous environment at approximately 400oC, the hydrogen diffused into the ZnO and occupied oxygen vacancies contributing to a reduction in intensity of Raman bands associated with the defect. At higher concentrations of hydrogen, generated during electrochemical polarization in aqueous solution at 25oC, the hydrogen diffused into the ZnO, both filling oxygen vacancies and populating interstitial sites in line with recent observations reported in the literature. In this latter role, hydrogen imparted sufficient electron density to the Zn and/or structural disorder to enhance vibration modes that are forbidden or typically weak in native ZnO. The results argue for the pervasive and varied chemistry of hydrogen in this oxide and may help explain the dependence of physical properties, especially electrical conductivity, on fabrication methods and environmental conditions.

  20. Fermentative Hydrogen Production: Influence of Application of Mesophilic and Thermophilic Bacteria on Mass and Energy Balances

    NARCIS (Netherlands)

    Foglia, D.; Wukovits, W.; Friedl, A.; Vrije, de G.J.; Claassen, P.A.M.

    2011-01-01

    Fermentation of biomass residues and second generation biomasses is a possible way to enable a sustainable production of hydrogen. The HYVOLUTION-project investigates the production of hydrogen by a 2-stage fermentation process of biomass. It consists of a dark fermentation step of sugars to produce

  1. Overtone Spectroscopy of Peroxyacetic Acid and Peroxyformic Acid : Influence of Intramolecular Hydrogen Bonding

    Science.gov (United States)

    Hazra, Montu K.; Kuang, Michelle; Sinha, Amitabha

    2010-06-01

    The absorption of solar radiation by hydrogen-bonded (H-bonded) complex, particularly those containing water, is important in atmospheric chemistry. However, because of their low concentration, intermolecular hydrogen bonded complexes of atmospheric interest are difficult to study in the gas phase. Consequently, our initial efforts have been directed towards investigating the spectroscopy of molecules with internal hydrogen bonds. In this talk, we present the vapor phase vibrational overtone spectra of peroxyacetic acid (PAA) and peroxyformic acid (PFA), two molecules of atmospheric importance, and discuss the effect of intramolecular hydrogen-bonding on their OH stretching overtone transition strength and band positions. A comparison of the results of PAA and PFA with those of other intramolecular H-bonded and non-H-bonded molecules provides a useful gauge of the extent of hydrogen bonding in these peroxyacids.

  2. Neutral interstellar hydrogen in the inner heliosphere under the influence of wavelength-dependent solar radiation pressure

    Science.gov (United States)

    Tarnopolski, S.; Bzowski, M.

    2009-01-01

    Context: With the plethora of detailed results from heliospheric missions such as Ulysses and SOHO and at the advent of the first mission dedicated to in situ studies of neutral heliospheric atoms IBEX, we have entered the era of precision heliospheric studies. Interpretation of these data requires precision modeling, with second-order effects quantitatively taken into account. Aims: We study the influence of the non-flat shape of the solar Lyman-α line on the distribution of neutral interstellar hydrogen in the inner heliosphere and assess the importance of this effect for interpretation of heliospheric in situ measurements. Methods: Based on available data, we (i) constructed a model of evolution for the solar Lyman-α line profile with solar activity; (ii) modified an existing test-particle code used to calculate the distribution of neutral interstellar hydrogen in the inner heliosphere so that it takes the dependence of radiation pressure on radial velocity into account; and (iii) compared results of the old and new version. Results: Discrepancies between the classical and Doppler models appear between ~5 and 3 AU and increase towards the Sun from a few percent to a factor of 1.5 at 1 AU. The classical model overestimates the density everywhere except for a ~60° cone around the downwind direction, where a density deficit appears. The magnitude of the discrepancies appreciably depends on the phase of the solar cycle, but only weakly on the parameters of the gas at the termination shock. For in situ measurements of neutral atoms performed at ~1 AU, like those planned for IBEX, the Doppler correction will need to be taken into account, because the modifications include both the magnitude and direction of the local flux by a few km s-1 and degrees, respectively, which, when unaccounted for, would introduce an error of a few km s-1 and degrees in determination of the magnitude and direction of the bulk velocity vector at the termination shock. Conclusions: The

  3. Low-cost fabrication of highly sensitive room temperature hydrogen sensor based on ordered mesoporous Co-doped TiO2 structure

    Science.gov (United States)

    Li, Zhong; Haidry, Azhar Ali; Wang, Tao; Yao, Zheng Jun

    2017-07-01

    The development of cost-effective gas sensors with improved sensing properties and minimum power consumption for room temperature hydrogen leakage monitoring is in increasing demand. In this context, this report focus on the facile fabrication of ordered mesoporous TiO2 via evaporation-induced self-assembly route. With the controlled doping threshold (3%Co-TiO2), the output resistance change to 1000 ppm H2 is ˜4.1 × 103 with the response time of 66 s. The sensor response exhibits power law dependence with an increase in the hydrogen concentration, where the power law coefficient was found not only specific to the kind of target gas but also related to temperature. Further, the effect of structure integrity with doping level and humidity on sensing characteristics is interpreted in terms of variation in surface potential eVS and depletion region w caused by the adsorption of molecular oxygen O2-.

  4. Sleep inertia, sleep homeostatic and circadian influences on higher-order cognitive functions.

    Science.gov (United States)

    Burke, Tina M; Scheer, Frank A J L; Ronda, Joseph M; Czeisler, Charles A; Wright, Kenneth P

    2015-08-01

    Sleep inertia, sleep homeostatic and circadian processes modulate cognition, including reaction time, memory, mood and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-day-long study that included two 14-day-long 28-h forced desynchrony protocols to examine separate and interacting influences of sleep inertia, sleep homeostasis and circadian phase on higher-order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved during the first ~2-4 h of wakefulness (decreasing sleep inertia); worsened thereafter until scheduled bedtime (increasing sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~09:00 and ~21:00 hours, respectively, in individuals with a habitual wake time of 07:00 hours). The relative influences of sleep inertia, sleep homeostasis and circadian phase depended on the specific higher-order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial-configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher-order cognitive processes are differentially sensitive to different sleep-wake regulatory processes. Differential modulation of cognitive functions by different sleep-wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation and/or upon awakening from sleep. © 2015 European Sleep Research Society.

  5. Researches on the influence of the slags formed in the installations on the hydrogen removal efficiency

    Directory of Open Access Journals (Sweden)

    Drǎgoi, F.

    2011-12-01

    Full Text Available Modern technology requires ever more high-quality steel and special steels, with properties corresponding to very different purposes. Because of the interdependence of the factors that determine the overall quality of the steel and those who determine the gas content, this is an issue of growing importance for the development, treatment and casting of steel. Slag plays an important part in the development phase no matter the process phase is. The influence of synthetic slags during LF treatment facility is examined based on the degree of removal of hydrogen. After processing the experimental data there has been established the optimal basicity variation on which one can determine the chemical composition of slag (CaO, SiO2, Al2O3, MgO for the secondary treatment of steel.

    La técnica moderna necesita cada vez más acero de calidad superior y aceros especiales, con propiedades adecuadas a unos propósitos muy amplios. Gracias a la interdependecia entre los factores que determinan el contenido de gases esta constituye un problema cada vez más importante para la elaboración, tratamiento y fundición de los aceros. Una gran importancia en el proceso de elaboración le corresponde a la escoria independientemente de la fase del proceso. Se analiza la influencia de la escoria sintética durante el tratamiento en la instalación LF sobre el grado de eliminación del hidrogeno. Después de procesar los datos experimentales se establecieron los campos óptimos de variación de la basicidad en base a la cual se puede determinar la composición química de la escoria (CaO, SiO2, Al2O3, MgO para el tratamiento secundario del acero.

  6. Influence of Hydrogen-Based Storage Systems on Self-Consumption and Self-Sufficiency of Residential Photovoltaic Systems

    OpenAIRE

    Christian Pötzinger; Markus Preißinger; Dieter Brüggemann

    2015-01-01

    This paper analyzes the behavior of residential solar-powered electrical energy storage systems. For this purpose, a simulation model based on MATLAB/Simulink is developed. Investigating both short-time and seasonal hydrogen-based storage systems, simulations on the basis of real weather data are processed on a timescale of 15 min for a consideration period of 3 years. A sensitivity analysis is conducted in order to identify the most important system parameters concerning the proportion of co...

  7. Influences of atomic hydrogen on porous low-k dielectric for 45-nm node

    Energy Technology Data Exchange (ETDEWEB)

    Tomioka, K. [Semiconductor Leading Edge Technologies, Inc., 16-1 Onogawa, Tsukuba, Ibaraki, 305-8569 (Japan)]. E-mail: tomioka.kazuhiro@selete.co.jp; Soda, E. [Semiconductor Leading Edge Technologies, Inc., 16-1 Onogawa, Tsukuba, Ibaraki, 305-8569 (Japan); Kobayashi, N. [Semiconductor Leading Edge Technologies, Inc., 16-1 Onogawa, Tsukuba, Ibaraki, 305-8569 (Japan); Takata, M. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan); Uda, S. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan); Ogushi, K. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan); Yuba, Y. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan); Akasaka, Y. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan)

    2007-04-23

    Atomic hydrogen generated by a heated tungsten catalyzer has been investigated in terms of the damage-less ash and restoration of damaged low-k dielectric. No difference of damaged thickness of low-k dielectric between before and after the ash by HF dip using patterned porous methyl silsesquioxane (MSQ) film was found. Moreover atomic hydrogen exposure slightly reduced capacitance of the micro-structured capacitor with the Cu wire and the CVD porous low-k dielectric.

  8. Temporal Dynamics of Hypothesis Generation: The Influences of Data Serial Order, Data Consistency, and Elicitation Timing

    Science.gov (United States)

    Lange, Nicholas D.; Thomas, Rick P.; Davelaar, Eddy J.

    2012-01-01

    The pre-decisional process of hypothesis generation is a ubiquitous cognitive faculty that we continually employ in an effort to understand our environment and thereby support appropriate judgments and decisions. Although we are beginning to understand the fundamental processes underlying hypothesis generation, little is known about how various temporal dynamics, inherent in real world generation tasks, influence the retrieval of hypotheses from long-term memory. This paper presents two experiments investigating three data acquisition dynamics in a simulated medical diagnosis task. The results indicate that the mere serial order of data, data consistency (with previously generated hypotheses), and mode of responding influence the hypothesis generation process. An extension of the HyGene computational model endowed with dynamic data acquisition processes is forwarded and explored to provide an account of the present data. PMID:22754547

  9. Efficient collective influence maximization in cascading processes with first-order transitions

    Science.gov (United States)

    Pei, Sen; Teng, Xian; Shaman, Jeffrey; Morone, Flaviano; Makse, Hernán A.

    2017-03-01

    In many social and biological networks, the collective dynamics of the entire system can be shaped by a small set of influential units through a global cascading process, manifested by an abrupt first-order transition in dynamical behaviors. Despite its importance in applications, efficient identification of multiple influential spreaders in cascading processes still remains a challenging task for large-scale networks. Here we address this issue by exploring the collective influence in general threshold models of cascading process. Our analysis reveals that the importance of spreaders is fixed by the subcritical paths along which cascades propagate: the number of subcritical paths attached to each spreader determines its contribution to global cascades. The concept of subcritical path allows us to introduce a scalable algorithm for massively large-scale networks. Results in both synthetic random graphs and real networks show that the proposed method can achieve larger collective influence given the same number of seeds compared with other scalable heuristic approaches.

  10. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    hydrogen embrittlement. The effects of hydrogen gas on mechanical properties such as tensile strength, ductility, fracture, low and high cycle fatigue, crack growth rate, and creep rupture are analyzed with respect to the general trends established from the HEE index values. It is observed that the severity of HE effects is also influenced by environmental factors such as pressure, temperature, and hydrogen gas purity. The severity of HE effects is also influenced by material factors such as surface finish, heat treatment, and product forms, compositions, grain direction, and crystal orientations.

  11. Influence of pectinolyttic and cellulotyc enzyme complexes on cashew bagasse maceration in order to obtain carotenoids.

    Science.gov (United States)

    Macedo, Manuella; Robrigues, Renata Débora Pinto; Pinto, Gustavo Adolfo Saavedra; de Brito, Edy Sousa

    2015-06-01

    Cashew apple bagasse is a byproduct of cashew peduncle juice processing. Such waste is a source of carotenoids, but it is usually discarded after the juice extraction. The objective of this work was to study the influence of pectinolytic and cellulolytic enzyme complexes on cashew bagasse maceration in order to obtain carotenoids. It was observed that maceration with the enzymatic complex Pectinex Batch AR showed a higher content of carotenoids, with an overall gain of 79 % over the control carried out without enzyme complex addition.

  12. Reduced Order Modeling of SLS Liquid Hydrogen Pre-Valve Flow Guide to Enable Rapid Transient Analysis

    Science.gov (United States)

    Brown, Andrew M.; Mulder, Andrew

    2017-01-01

    NASA is developing a new launch vehicle, called the Space Launch System (SLS), which is intended on taking humans out of low earth orbit to destinations including the moon, asteroids, and Mars. The propulsion system for the core stage of this vehicle includes four RS-25 Liquid Hydrogen/Oxygen rocket engines. These engines are upgraded versions of the Space Shuttle Main Engines (SSME); the upgrades include higher power levels and affordability enhancements. As with any new vehicle, the Main Propulsion System (MPS), which include the feedlines and ancillary hardware connecting the engines to the fuel and oxidizer tanks, had to be redesigned (figure 1 - export clearance in progress), as the previous MPS for the SSME's was inherently part of the Space Shuttle System, which had a completely different overall configuration.

  13. Influence of activated carbon amended ASBR on anaerobic fermentative hydrogen production

    DEFF Research Database (Denmark)

    Xie, Li; Wang, Lei; Zhou, Qi

    2013-01-01

    The effect of activated carbon amended ASBR on fermentative bio-hydgrogen production from glucose was evaluated at hydraulic retention time (HRTs) ranging from 48 h to 12 h with initial pH of 6.0 at the system temperature of 60°C. Experimental results showed that the performance of activated carbon...... amended anazrobic seguencs batch reactor (ASBRs) was more stable than that of ASBRs without activated carbon addition regarding on hydrogen production and pH. Higher hydrogen yield(HY) and hydrogen producing rate(HPR) were observed in the activated carbon amended ASBRs, with 65%, 63%, 54%, 56% enhancement...... of hydrogen yield in smaller size activated carbon amended reactor under the tested HRT ranges, and the maximum HPR of (7.09±0.31)L·(L·d)-1 and HY of (1.42±0.03) mol·mol-1 was obtained at HRT of 12h. The major soluble products form hydrogen fermentation were n-butyric acid and acetic acid, accounting for 46...

  14. Hydroformylation of Cyclohexene with Carbon Dioxide and Hydrogen Using Ruthenium Carbonyl Catalyst: Influence of Pressures of Gaseous Components

    Directory of Open Access Journals (Sweden)

    Masahiko Arai

    2007-08-01

    Full Text Available Hydroformylation of cyclohexene was studied with a catalyst system ofRu3(CO12 and LiCl using H2 and CO2 instead of CO in NMP. The influence of H2 andCO2 pressures on the total conversion and the product distribution was examined. It wasshown that increasing total pressure of H2 and CO2 promoted the reverse water gas shiftreaction and increased the yield of cyclohexanecarboxaldehyde. Its hydrogenation tocyclohexanemethanol was promoted with increasing H2 pressure but suppressed withincreasing CO2 pressure. Cyclohexane was also formed along with those products and thisdirect hydrogenation was suppressed with increasing CO2 pressure. The roles of CO2 as apromoter as well as a reactant were further examined by phase behavior observations andhigh pressure FTIR measurements.

  15. [The influence of phenylephrine and tropicamide on higher order monochromatic aberrations].

    Science.gov (United States)

    Jurkutat, S; Loosberg, B; Hemmelmann, C; Dawszynski, J; Strobel, J

    2007-03-01

    For wave-front guided corneal surgery, measuring higher order monochromatic aberrations in mydriasis is needed. However, a potential influence of mydriatic drugs on such aberrations could distort the ablation profile. Wave-front analysis was carried out on 20 (tropicamide) and 19 (phenylephrine) eyes after dark adaptation, followed by measurement after the instillation of the mydriatics one after another. Phenylephrine had no significant influence on the wave-front; neither sphere nor RMS data differed from those taken after dark adaptation. After instilling tropicamide, significant changes in Z(2) (0) and, in parallel, also of the sphere were found. The RMS showed no significant difference, only the spherical aberration Z(4) (0) was reduced by an average of 0.035 microm. The wave-front changes individually through the mydriasis due to phenylephrine and tropicamide. In the case of tropicamide, the deviation is statistically significant. Therefore, abandonment of these mydriatics before refractive surgery can be recommended, as can the use physiological pupil dilatation. Because of its lower influence, phenylephrine should be the first choice if dimout effects no adequate mydriasis.

  16. Polyelectrolyte conformational transition in aqueous solvent mixture influenced by hydrophobic interactions and hydrogen bonding effects: PAA-water-ethanol.

    Science.gov (United States)

    Sappidi, Praveenkumar; Natarajan, Upendra

    2016-03-01

    Molecular dynamics simulations of poly(acrylic acid) PAA chain in water-ethanol mixture were performed for un-ionized and ionized cases at different degree-of-ionization 0%, 80% and 100% of PAA chain by Na(+) counter-ions and co-solvent (ethanol) concentration in the range 0-90vol% ethanol. Aspects of structure and dynamics were investigated via atom pair correlation functions, number and relaxation of hydrogen bonds, nearest-neighbor coordination numbers, and dihedral angle distribution function for back-bone and side-groups of the chain. With increase in ethanol concentration, chain swelling is observed for un-ionized chain (f=0) and on the contrary chain shrinkage is observed for partially and fully ionized cases (i.e., f=0.8 and 1). For un-ionized PAA, with increase in ethanol fraction ϕeth the number of PAA-ethanol hydrogen bonds increases while PAA-water decreases. Increase in ϕeth leads to PAA chain expansion for un-ionized case and chain shrinkage for ionized case, in agreement with experimental observations on this system. For ionized-PAA case, chain shrinkage is found to be influenced by intermolecular hydrogen bonding with water as well as ethanol. The localization of ethanol molecules near the un-ionized PAA backbone at higher levels of ethanol is facilitated by a displacement of water molecules indicating presence of specific ethanol hydration shell, as confirmed by results of the RDF curves and coordination number calculations. This behavior, controlled by hydrogen bonding provides a significant contribution to such a conformational transition behavior of the polyelectrolyte chain. The interactions between counter-ions and charges on the PAA chain also influence chain collapse. The underlying origins of polyelectrolyte chain collapse in water-alcohol mixtures are brought out for the first time via explicit MD simulations by this study. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Engineering Synechocystis PCC6803 for hydrogen production: influence on the tolerance to oxidative and sugar stresses.

    Directory of Open Access Journals (Sweden)

    Marcia Ortega-Ramos

    Full Text Available In the prospect of engineering cyanobacteria for the biological photoproduction of hydrogen, we have studied the hydrogen production machine in the model unicellular strain Synechocystis PCC6803 through gene deletion, and overexpression (constitutive or controlled by the growth temperature. We demonstrate that the hydrogenase-encoding hoxEFUYH operon is dispensable to standard photoautotrophic growth in absence of stress, and it operates in cell defense against oxidative (H₂O₂ and sugar (glucose and glycerol stresses. Furthermore, we showed that the simultaneous over-production of the proteins HoxEFUYH and HypABCDE (assembly of hydrogenase, combined to an increase in nickel availability, led to an approximately 20-fold increase in the level of active hydrogenase. These novel results and mutants have major implications for those interested in hydrogenase, hydrogen production and redox metabolism, and their connections with environmental conditions.

  18. Olfactory Performance Can Be Influenced by the Presentation Order, Background Noise, and Positive Concurrent Feedback.

    Science.gov (United States)

    Walliczek-Dworschak, Ute; Pellegrino, Robert; Lee, Shangwa; Hummel, Cornelia; Hähner, Antje; Hummel, Thomas

    2016-10-01

    Sniffin' Sticks have become a popular procedure to measure overall olfactory functionality with 3 subtest: phenyl ethyl alcohol threshold test (T), discrimination (D), and identification (I). However, several procedural components specified by the original paper have not been tested nor has the impact of deviations been measured. The aim of the present work was to measure olfactory performance under modified testing procedures. First, the reverse order of subtests (IDT) was compared with more standard practices (TDI). Next, the possible impact of background noise and positive concurrent feedback were assessed. A total of 120 individuals participated in the study where the 3 conditional experiments, each involving 40 participants, were completed. Testing procedures that reversed the presentation order of subtests (I->D->T) scored a significantly lower overall TDI score than standard testing order with the threshold subtest being the most influenced. Additionally, nonverbal background noise lowered overall olfactory performance while concurrent feedback modulated threshold performance. These results emphasize the importance of testing parameters where olfactory perception and tasks may be modulated by adaptation and attentional distraction, respectively. This study helped furthermore to demonstrate that the investigated 3 deviations from the standard procedure revealed a significant impact on the performance outcome in olfactory assessment using the Sniffin' Sticks. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Hydrogen injection scheme influence on flow structure in supersonic combustor of constant cross-section

    Science.gov (United States)

    Starov, A. V.; Goldfeld, M. A.

    2017-10-01

    The efficiency of using two variants of hydrogen injection (distributed and non-distributed injection from vertical pylons) is experimentally investigated. The tests are performed in the attached pipeline regime with the Mach number at the model combustor entrance M=2. The combustion chamber has a backward-facing step at the entrance and slotted channels for combustion stabilization. The tested variants of injection differ basically by the shapes of the fuel jets and, correspondingly, by the hydrogen distribution over the combustor. As a result, distributed injection is found to provide faster ignition, upstream displacement of the elevated pressure region, and more intense combustion over the entire combustor volume.

  20. The effect of mixing and changing the order of feeding oats and chopped alfalfa to horses on: glycaemic and insulinaemic responses, and breath hydrogen and methane production.

    Science.gov (United States)

    Vervuert, I; Voigt, K; Hollands, T; Cuddeford, D; Coenen, M

    2009-10-01

    The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three different ways: (i) alfalfa followed by oats (A/O), (ii) oats followed by alfalfa (O/A) or (iii) a mixture of alfalfa and oats (A + O). Oats alone were used as a control. Blood and breath were collected after the test meal was fed at the end of a 11.5-h overnight fast following a 10-day acclimatization period. The highest glycaemic and insulinaemic responses were measured when the A/O and O/A diets orders were fed, whereas most hydrogen was produced after feeding oats alone. It was concluded that adding alfalfa chaff to a meal of oats prolonged the pre-caecal digestion of starch, but there was no evidence for any effect on pre-caecal starch digestibility.

  1. U.S. Department of Energy FreedomCar & Vehicle Technologies Program CARB Executive Order Exemption Process for a Hydrogen-fueled Internal Combustion engine Vehicle -- Status Report

    Energy Technology Data Exchange (ETDEWEB)

    2008-04-01

    The CARB Executive Order Exemption Process for a Hydrogen-fueled Internal Combustion Engine Vehicle was undertaken to define the requirements to achieve a California Air Resource Board Executive Order for a hydrogenfueled vehicle retrofit kit. A 2005 to 2006 General Motors Company Sierra/Chevrolet Silverado 1500HD pickup was assumed to be the build-from vehicle for the retrofit kit. The emissions demonstration was determined not to pose a significant hurdle due to the non-hydrocarbon-based fuel and lean-burn operation. However, significant work was determined to be necessary for Onboard Diagnostics Level II compliance. Therefore, it is recommended that an Experimental Permit be obtained from the California Air Resource Board to license and operate the vehicles for the durability of the demonstration in support of preparing a fully compliant and certifiable package that can be submitted.

  2. Influence of second sphere hydrogen bonding interaction on a manganese(II)-aquo complex.

    Science.gov (United States)

    El Ghachtouli, Sanae; Guillot, Régis; Dorlet, Pierre; Anxolabéhère-Mallart, Elodie; Aukauloo, Ally

    2012-02-14

    We have developed a pentadentate N(4)O ligand scaffold with a benzimidazole group placed in a rigid fashion to develop hydrogen bonding interaction with the ligand in the sixth position. The mononuclear Mn(II) complex with a water molecule was isolated and characterized. We discuss the role of the outer sphere ligand in stabilising a Mn(II)-aquo complex.

  3. Influence of orocaecal transit time on hydrogen excretion after carbohydrate malabsorption

    DEFF Research Database (Denmark)

    Rumessen, J J; Hamberg, O; Gudmand-Høyer, E

    1989-01-01

    The aim of the present study was to determine whether changes in orocaecal transit time (OCTT) affect the magnitude of the breath hydrogen (H2) excretion after ingestion of unabsorbable carbohydrate. We studied eight healthy subjects by interval sampling of end expiratory H2 concentration for 12...

  4. Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

    Science.gov (United States)

    Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

    2013-05-30

    Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/AlS.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/AlS.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/AlS.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

  5. Efficient collective influence maximization in cascading processes with first-order transitions

    Science.gov (United States)

    Pei, Sen; Teng, Xian; Shaman, Jeffrey; Morone, Flaviano; Makse, Hernán A.

    2017-01-01

    In many social and biological networks, the collective dynamics of the entire system can be shaped by a small set of influential units through a global cascading process, manifested by an abrupt first-order transition in dynamical behaviors. Despite its importance in applications, efficient identification of multiple influential spreaders in cascading processes still remains a challenging task for large-scale networks. Here we address this issue by exploring the collective influence in general threshold models of cascading process. Our analysis reveals that the importance of spreaders is fixed by the subcritical paths along which cascades propagate: the number of subcritical paths attached to each spreader determines its contribution to global cascades. The concept of subcritical path allows us to introduce a scalable algorithm for massively large-scale networks. Results in both synthetic random graphs and real networks show that the proposed method can achieve larger collective influence given the same number of seeds compared with other scalable heuristic approaches. PMID:28349988

  6. How does participation in inquiry-based activities influence gifted students' higher order thinking?

    Science.gov (United States)

    Reger, Barbara H.

    Inquiry-based learning is considered a useful technique to strengthen the critical thinking skills of students. The National Science Standards emphasize its use and the complexities and challenge it provides are well suited for meeting the needs of the gifted. While many studies have documented the effectiveness of this type of instruction, there is a lack of research on growth in higher-order thinking through participation in science inquiry. This study investigated such growth among a small group of gifted fifth-grade students. In this study a group of fifth-grade gifted science students completed a series of three forensics inquiry lessons, and documented questions, ideas and reflections as they constructed evidence to solve a crime. From this class of students, one small group was purposely selected to serve as the focus of the study. Using qualitative techniques, the questions and statements students made as they interacted in the activity were analyzed. Videotaped comments and student logs were coded for emerging patterns and also examined for evidence of increased levels of higher-order thinking based on a rubric that was designed using the six levels of Bloom's Taxonomy. Evidence from this study showed marked increase in and deeper levels of higher-order thinking for two of the students. The other boy and girl showed progress using the inquiry activities, but it was not as evident. The social dynamics of the group seemed to hinder one girl's participation during some of the activities. The social interactions played a role in strengthening the exchange of ideas and thinking skills for the others. The teacher had a tremendous influence over the production of higher-level statements by modeling that level of thinking as she questioned the students. Through her practice of answering a question with a question, she gradually solicited more analytical thinking from her students.

  7. Mesophilic hydrogen production in acidogenic packed-bed reactors (APBR) using raw sugarcane vinasse as substrate: Influence of support materials.

    Science.gov (United States)

    Nunes Ferraz Júnior, Antônio Djalma; Etchebehere, Claudia; Zaiat, Marcelo

    2015-08-01

    Bio-hydrogen production from sugarcane vinasse in anaerobic up-flow packed-bed reactors (APBR) was evaluated. Four types of support materials, expanded clay (EC), charcoal (Ch), porous ceramic (PC), and low-density polyethylene (LDP) were tested as support for biomass attachment. APBR (working volume - 2.3 L) were operated in parallel at a hydraulic retention time of 24 h, an organic loading rate of 36.2 kg-COD m(-3) d(-1), at 25 °C. Maximum volumetric hydrogen production values of 509.5, 404, 81.4 and 10.3 mL-H2 d(-1) L(-1)reactor and maximum yields of 3.2, 2.6, 0.4 and 0.05 mol-H2 mol(-1) carbohydrates total, were observed during the monitoring of the reactors filled with LDP, EC, Ch and PC, respectively. Thus, indicating the strong influence of the support material on H2 production. LDP was the most appropriate material for hydrogen production among the materials evaluated. 16S rRNA gene by Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis and scanning electron microscopy confirmed the selection of different microbial populations. 454-pyrosequencing performed on samples from APBR filled with LDP revealed the presence of hydrogen-producing organisms (Clostridium and Pectinatus), lactic acid bacteria and non-fermentative organisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Influence of excited states on the energy loss of fast ions in a hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, B. (Max-Planck-Institut fuer Quantenoptik, D-8046 Garching, Germany (DE)); Peter, T. (Max-Planck-Institut fuer Chemie, D-6500 Mainz, Germany (DE))

    1991-04-01

    Stopping power calculations of fast ions penetrating a hydrogen plasma target in local thermodynamic equilibrium at arbitrary temperatures are performed. Excited state contributions to the energy loss are included in the framework of the Bethe formalism. Average ionization potentials for the excited ions are given in a quasiclassical approximation. It is shown that the net effect is an enhancement of the stopping power compared to the energy loss when assuming all atoms to be in their ground state.

  9. Influence of Adsorption Geometry in the Heterogeneous Enantioselective Catalytic Hydrogenation of a Prototypical Enone

    OpenAIRE

    Beaumont, SK; Kyriakou, G; Watson, DJ; Vaughan, OPH; Papageorgiou, AC; Lambert, RM

    2010-01-01

    Asymmetric catalysis is of paramount importance in organic synthesis and, in current practice, is achieved by means of homogeneous catalysts. The ability to catalyze such reactions heterogeneously would have a major impact both in the research laboratory and in the production of fine chemicals and pharmaceuticals, yet heterogeneous asymmetric hydrogenation of C═C bonds remains hardly explored. Very recently, we demonstrated how chiral ligands that anchor robustly to the surface of Pd nanopart...

  10. Influence of Growth Medium on Hydrogen Peroxide and Bacteriocin Production of Lactobacillus Strains

    Directory of Open Access Journals (Sweden)

    Edina Németh

    2005-01-01

    Full Text Available This study was conducted to investigate the inhibitory effect of bacteriocin and the production of hydrogen peroxide by four non-starter lactic acid bacteria, Lactobacillus plantarum 2142, Lactobacillus curvatus 2770, Lactobacillus curvatus 2775, Lactobacillus casei subsp. pseudoplantarum 2750 and the probiotic strain Lactobacillus casei Shirota, propagated in de Man Rogosa Sharpe (MRS and tomato juice (TJ broth. The methods were a commonly used agar diffusion technique and a microtiter assay method. The best peroxide-producing Lactobacillus strain was selected for screening the inhibitory activity against Listeria monocytogenes, Bacillus cereus, Escherichia coli and the activity of bacteriocins against Lactobacillus sakei and Candida glabrata. All of the investigated lactic acid bacteria (LAB strains grown in MRS broth produced the highest concentration of hydrogen peroxide ranging from 2–6 g/mL after 72 h of storage. L. plantarum 2142 produced enough hydrogen peroxide already after 24 h at 5 °C in phosphate buffer to inhibit the growth of L. monocytogenes and B. cereus. Crude bacteriocin suspension from the investigated LAB inhibited only slightly the growth of L. sakei, however, the same suspension from MRS completely inhibited the 6-fold diluted yeast suspension. The concentrated bacteriocin suspensions from the both broths inhibited the growth of L. sakei completely. Among the strains, L. plantarum 2142 seemed to be the best peroxide and bacteriocin producer, and the antimicrobial metabolite production was better in MRS than in TJ broth.

  11. Influence of Sulfuric Acid on the Performance of Ruthenium-based Catalysts in the Liquid-Phase Hydrogenation of Levulinic Acid to γ-Valerolactone

    NARCIS (Netherlands)

    Ftouni, Jamal; Genuino, Homer C.|info:eu-repo/dai/nl/371571685; Muñoz-murillo, Ara; Bruijnincx, Pieter C. A.|info:eu-repo/dai/nl/33799529X; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397

    2017-01-01

    The presence of biogenic or process-derived impurities poses a major problem on the efficient catalytic hydrogenation of biomass-derived levulinic acid to γ-valerolactone; hence, studies on their influence on catalyst stability are now required. Herein, the influence of sulfuric acid as feed

  12. Influence of time delay on fractional-order PI-controlled system for a second-order oscillatory plant model with time delay

    Directory of Open Access Journals (Sweden)

    Sadalla Talar

    2017-12-01

    Full Text Available The paper aims at presenting the influence of an open-loop time delay on the stability and tracking performance of a second-order open-loop system and continuoustime fractional-order PI controller. The tuning method of this controller is based on Hermite- Biehler and Pontryagin theorems, and the tracking performance is evaluated on the basis of two integral performance indices, namely IAE and ISE. The paper extends the results and methodology presented in previous work of the authors to analysis of the influence of time delay on the closed-loop system taking its destabilizing properties into account, as well as concerning possible application of the presented results and used models.

  13. Word Order and Voice Influence the Timing of Verb Planning in German Sentence Production

    Science.gov (United States)

    Sauppe, Sebastian

    2017-01-01

    Theories of incremental sentence production make different assumptions about when speakers encode information about described events and when verbs are selected, accordingly. An eye tracking experiment on German testing the predictions from linear and hierarchical incrementality about the timing of event encoding and verb planning is reported. In the experiment, participants described depictions of two-participant events with sentences that differed in voice and word order. Verb-medial active sentences and actives and passives with sentence-final verbs were compared. Linear incrementality predicts that sentences with verbs placed early differ from verb-final sentences because verbs are assumed to only be planned shortly before they are articulated. By contrast, hierarchical incrementality assumes that speakers start planning with relational encoding of the event. A weak version of hierarchical incrementality assumes that only the action is encoded at the outset of formulation and selection of lexical verbs only occurs shortly before they are articulated, leading to the prediction of different fixation patterns for verb-medial and verb-final sentences. A strong version of hierarchical incrementality predicts no differences between verb-medial and verb-final sentences because it assumes that verbs are always lexically selected early in the formulation process. Based on growth curve analyses of fixations to agent and patient characters in the described pictures, and the influence of character humanness and the lack of an influence of the visual salience of characters on speakers' choice of active or passive voice, the current results suggest that while verb planning does not necessarily occur early during formulation, speakers of German always create an event representation early. PMID:29018379

  14. Word Order and Voice Influence the Timing of Verb Planning in German Sentence Production

    Directory of Open Access Journals (Sweden)

    Sebastian Sauppe

    2017-09-01

    Full Text Available Theories of incremental sentence production make different assumptions about when speakers encode information about described events and when verbs are selected, accordingly. An eye tracking experiment on German testing the predictions from linear and hierarchical incrementality about the timing of event encoding and verb planning is reported. In the experiment, participants described depictions of two-participant events with sentences that differed in voice and word order. Verb-medial active sentences and actives and passives with sentence-final verbs were compared. Linear incrementality predicts that sentences with verbs placed early differ from verb-final sentences because verbs are assumed to only be planned shortly before they are articulated. By contrast, hierarchical incrementality assumes that speakers start planning with relational encoding of the event. A weak version of hierarchical incrementality assumes that only the action is encoded at the outset of formulation and selection of lexical verbs only occurs shortly before they are articulated, leading to the prediction of different fixation patterns for verb-medial and verb-final sentences. A strong version of hierarchical incrementality predicts no differences between verb-medial and verb-final sentences because it assumes that verbs are always lexically selected early in the formulation process. Based on growth curve analyses of fixations to agent and patient characters in the described pictures, and the influence of character humanness and the lack of an influence of the visual salience of characters on speakers' choice of active or passive voice, the current results suggest that while verb planning does not necessarily occur early during formulation, speakers of German always create an event representation early.

  15. Perceptions of authors' contributions are influenced by both byline order and designation of corresponding author.

    Science.gov (United States)

    Bhandari, Mohit; Guyatt, Gordon H; Kulkarni, Abhaya V; Devereaux, Philip J; Leece, Pamela; Bajammal, Sohail; Heels-Ansdell, Diane; Busse, Jason W

    2014-09-01

    We explored how readers interpret authors' roles based on authorship order and corresponding author. We conducted a cross-sectional survey of all 291 Surgical and Medical Chairpersons across North America. We developed hypothetical study and authorship bylines with five authors varying the corresponding author as first or last author. Respondents reported their perceptions about the authors' roles in the study and the most prestigious authorship position. We used multinomial regression to explore the results. One hundred sixty-five chairpersons (response rate: 57%) completed our survey. When the first author was designated as corresponding author, most of the respondents assumed that this author had taken the lead in study design (55.3%) and analysis and interpretation of data (51.2%). When the last author (fifth) was designated as corresponding, perceptions of the first author's role in study concept and design (odds ratio [OR] = 0.25, 95% confidence interval [CI]: 0.15, 0.41) and analysis and interpretation of results (OR = 0.22, 95% CI: 0.13, 0.38) decreased significantly. Overall prestige of the last author position increased significantly when designated as corresponding author (OR = 4.0, 95% CI: 2.4, 6.4). Academic department chairs' perception of authors' contributions was influenced by corresponding author designation. Without authors' explicit contributions in research articles, many readers may draw false conclusions about author credit and accountability. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Influence of Catalase Activity on Resistance of Coagulase-positive Staphylococci to Hydrogen Peroxide1

    Science.gov (United States)

    Amin, V. M.; Olson, N. F.

    1968-01-01

    Catalase activities of intact cells and cell-free extracts of coagulase-positive staphylococcal cultures 105B and 558D isolated from milk, culture 25042 from a clinical source, and Staphylococcus aureus 196E were determined at 32.2 C. Cultures were treated with 0.025 and 0.05% hydrogen peroxide at 37.8 and 54.4 C and without hydrogen peroxide at 54.4 C to determine the relationship between catalase activity and resistance to these treatments. The relationship held true for cultures 105B and 196E; culture 105B had the lowest catalase activity and lowest resistance to H2O2 at 37.8 C, whereas S. aureus 196E possessed a high catalase activity and was most resistant at 37.8 C. Catalase activities of cell-free extracts of cultures 25042, 558, and 196E were similar, but resistance to H2O2 at 37.8 C was greater for culture 196E. The lower resistance of culture 25042 was related to low catalase activities of whole cells of this culture, which were only one-third that of whole cells of culture 196E. Culture 558 was least resistant to heat treatment at 54.4 C and showed the greatest sensitivity to added H2O2 at this temperature. PMID:5645413

  17. Influence of nitrogen doping in sumanene framework toward hydrogen storage: A computational study.

    Science.gov (United States)

    Reisi-Vanani, Adel; Shamsali, Fatemeh

    2017-09-01

    Two conditions are important to obtain appropriate substances for hydrogen storage; high surface area and fitting binding energy (BE). Doping is a key strategy that improves BE. We investigated hydrogen adsorption onto twenty six nitrogen disubstituted isomers of sumanene (C19N2H12) by MP2/6-311++G(d,p)//B3LYP/6-31+G(d) and M06-2X/6-31+G(d) levels of theory. Effect of nitrogen doping in different positions of sumanene was checked. To obtain better BE, basis set superposition error (BSSE) and zero point energy (ZPE) corrections were used. Anticipating of adsorption sites and extra details about adsorption process was done by molecular electrostatic potential (MEP) surfaces. Various types of density of state (DOS) diagrams such as total DOS (TDOS), projected DOS (PDOS) and overlap population DOS (OPDOS) and natural bond orbital (NBO) analysis were used to find better insight on the adsorption properties. In addition of temperature depending of the BE, HOMO-LUMO gap (HLG), dipole moment, reactivity and stability, bowl depth and natural population analysis (NPA) of the isomers were studied. A physisorption mechanism for adsorption was proposed and a trivial change was seen. Place of nitrogen atoms in sumanene frame causes to binding energy increases or decreases compared with pristine sumanene. The best and the worst isomers and category of isomers were suggested. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The kinetics of the hydrogen chloride oxidation

    Directory of Open Access Journals (Sweden)

    Gonzalez Martinez Isai

    2013-01-01

    Full Text Available Hydrogen chloride (HCl oxidation has been investigated on technical membrane electrode assemblies in a cyclone flow cell. Influence of Nafion loading, temperature and hydrogen chloride mole fraction in the gas phase has been studied. The apparent kinetic parameters like reaction order with respect to HCl, Tafel slope and activation energy have been determined from polarization data. The apparent kinetic parameters suggest that the recombination of adsorbed Cl intermediate is the rate determining step.

  19. Approach to characterization of the higher order structure of disulfide-containing proteins using hydrogen/deuterium exchange and top-down mass spectrometry.

    Science.gov (United States)

    Wang, Guanbo; Kaltashov, Igor A

    2014-08-05

    Top-down hydrogen/deuterium exchange (HDX) with mass spectrometric (MS) detection has recently matured to become a potent biophysical tool capable of providing valuable information on higher order structure and conformational dynamics of proteins at an unprecedented level of structural detail. However, the scope of the proteins amenable to the analysis by top-down HDX MS still remains limited, with the protein size and the presence of disulfide bonds being the two most important limiting factors. While the limitations imposed by the physical size of the proteins gradually become more relaxed as the sensitivity, resolution and dynamic range of modern MS instrumentation continue to improve at an ever accelerating pace, the presence of the disulfide linkages remains a much less forgiving limitation even for the proteins of relatively modest size. To circumvent this problem, we introduce an online chemical reduction step following completion and quenching of the HDX reactions and prior to the top-down MS measurements of deuterium occupancy of individual backbone amides. Application of the new methodology to the top-down HDX MS characterization of a small (99 residue long) disulfide-containing protein β2-microglobulin allowed the backbone amide protection to be probed with nearly a single-residue resolution across the entire sequence. The high-resolution backbone protection pattern deduced from the top-down HDX MS measurements carried out under native conditions is in excellent agreement with the crystal structure of the protein and high-resolution NMR data, suggesting that introduction of the chemical reduction step to the top-down routine does not trigger hydrogen scrambling either during the electrospray ionization process or in the gas phase prior to the protein ion dissociation.

  20. Substituent Effects in CH Hydrogen Bond Interactions: Linear Free Energy Relationships and Influence of Anions.

    Science.gov (United States)

    Tresca, Blakely W; Hansen, Ryan J; Chau, Calvin V; Hay, Benjamin P; Zakharov, Lev N; Haley, Michael M; Johnson, Darren W

    2015-12-02

    Aryl CH hydrogen bonds (HBs) are now commonly recognized as important factors in a number of fields, including molecular biology, stereoselective catalysis, and anion supramolecular chemistry. As the utility of CH HBs has grown, so to has the need to understand the structure-activity relationship for tuning both their strength and selectivity. Although there has been significant computational effort in this area, an experimental study of the substituent effects on CH HBs has not been previously undertaken. Herein we disclose a systematic study of a single CH HB by using traditional urea donors as directing groups in a supramolecular binding cavity. Experimentally determined association constants are examined by a combination of computational (electrostatic potential) and empirical (σm and σp) values for substituent effects. The dominance of electrostatic parameters, as observed in a computational DFT study, is consistent with current CH HB theory; however, a novel anion dependence of the substituent effects is revealed in solution.

  1. Influence of the fineness of grinding coal on the results in liquid-phase hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Rank, V.

    1944-02-08

    This short note reported older results of experiments on brown coal from Boehlen, of which two different samples were hydrogenated at 250 atm, with each sample ground to a different degree of fineness. In sieving with a sieve of 16,900 mesh, 76.8% of one sample went through, whereas only 63.4% of the other sample went through. The more finely ground sample gave better values of coal decomposition (98.8% vs. 97.7%), yield of gasoline and middle oil (0.30 kg/liter/hr vs. 0.26), and losses to gas formation (19.3% vs. 20.7%). The experiments were carried out in a 10-liter oven.

  2. Hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Donath, E.

    1942-10-16

    This report mentioned that not very severe demands for purity were made on the hydrogen used in hydrogenation of coal or similar raw materials, because the catalysts were not very sensitive to poisoning. However, the hydrogenation plants tried to remove most impurities anyway by means of oil washes. The report included a table giving the amount of wash oil used up and the amount of hydrogen lost by dissolving into the wash oil used up and the amount of hydrogen lost by dissolving into the wash oil in order to remove 1% of various impurities from 1000 m/sup 3/ of the circulating gas. The amounts of wash oil used up were 1.1 m/sup 3/ for removing 1% nitrogen, 0.3 m/sup 3/ for 1% carbon monoxide, 0.03 m/sup 3/ for 1% methane. The amount of hydrogen lost was 28 m/sup 3/ for 1% nitrogen, 9 m/sup 3/ for 1% methane and ranged from 9 m/sup 3/ to 39 m/sup 3/ for 1% carbon monoxide and 1 m/sup 3/ to 41 m/sup 3/ for carbon dioxide depending on whether the removal was done in liquid phase or vapor phase and with or without reduction of the oxide to methane. Next the report listed and described the major processes used in German hydrogenation plants to produce hydrogen. Most of them produced water gas, which then had its carbon monoxide changed to carbon dioxide, and the carbon oxides washed out with water under pressure and copper hydroxide solution. The methods included the Winkler, Pintsch-Hillebrand, and Schmalfeldt-Wintershall processes, as well as roasting of coke in a rotating generator, splitting of gases formed during hydrogenation, and separation of cokery gas into its components by the Linde process.

  3. Influences of species of metals and supports on the hydrogenation activity of carbon-supported metal sulfides catalysts; Tanso biryushi tanji shokubai no suisoka kassei ni taisuru kassei kinzoku oyobi tantaishu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sakanishi, K.; Hasuo, H.; Taniguchi, H.; Nagamatsu, T.; Mochida, I. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1996-10-28

    In order to design catalysts suitable for primary liquefaction stage and secondary upgrading stage respectively in the multi-stage liquefaction process, various carbon-supported catalysts were prepared. Catalytic activities of them were investigated for the hydrogenation of 1-methylnaphthalene, to discuss the influences of metals and carbon species on the catalytic activity. Various water soluble and oil soluble Mo and Ni salts were used for NiMo supported catalysts. Among various carbon supports, Ketjen Black (KB) was effective for preparing the catalyst showing the most excellent hydrogenation activity. The KB and Black Pearl 2000 (BP2000) showing high hydrogenation activity were fine particles having high specific surface area more than 1000 m{sup 2}/g and primary particle diameter around 30 nm. This was inferred to contribute to the high dispersion support of active metals. Since such fine particles of carbon exhibited hydrophobic surface, they were suitable for preparing catalysts from the methanol-soluble metals. Although Ni and Mo added iron-based catalysts provided lower aromatic hydrogenation activity, they exhibited liquefaction activity competing with the NiMo/KB catalyst. 3 refs., 1 fig., 3 tabs.

  4. The influence of natural tocopherols during thermal oxidation of refined and partially hydrogenated soybean oils

    Directory of Open Access Journals (Sweden)

    Barrera-Arellano, D.

    2005-03-01

    Full Text Available Samples of refined and partially hydrogenated soybean oils, with iodine values between 60 and 130, tocopherol-stripped or not by aluminium oxide treatment, were submitted to thermal oxidation, at 180 °C (during for 10 hours. Samples were collected at 0, 2, 5, 8 and 10 hours, for the determination of dimers and polymers (degradation compounds and tocopherols. The relation of iodine value to the formation of dimers and polymers and the role of originally present tocopherols in the protection of fats and oils against thermal degradation was verified. The degradation curves for tocopherols showed that α and γ -tocopherols were destroyed faster than β and δ -tocopherols. In addition, the degradation rate of tocopherols was greater in the more saturated fats. The formation of dimers and polymers was greater in the oil than in the hydrogenated samples and in the samples treated with aluminium oxide with respect to the original, untreated samples.Muestras de aceites refinados y parcialmente hidrogenados de soja, con índices de yodo entre 60 y 130, tratadas o no con óxido de aluminio para eliminar los tocoferoles naturales presentes en los aceites, fueron sometidas a termoxidación, a 180 °C durante 10 horas. Se tomaron muestras en los tiempos 0, 2, 5, 8 y 10 horas, para determinación de dímeros y polímeros (compuestos de degradación y de tocoferoles. Se verificó la relación del índice de yodo con la formación de dímeros y polímeros, y también el papel de los tocoferoles originales del aceite y de las grasas en la protección contra la degradación térmica. Las curvas de degradación de los tocoferoles mostraron la destrucción más rápida de α y γ -tocoferoles, respecto a β y δ-tocoferoles. Además, la degradación de los tocoferoles ocurrió a mayor velocidad en las grasas más saturadas. La formación de dímeros y polímeros fue mayor en el aceite que en las muestras hidrogenadas y en las muestras tratadas

  5. Influence of metal doping of a MOF-74 framework on hydrogen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Botas, J.A.; Calleja, G.; Orcajo, M.G. [Rey Juan Carlos Univ., Madrid (Spain). Dept. of Chemical and Energy Technology; Sanchez-Sanchez, M. [CSIC, Madrid (Spain). Inst. de Catalisis y Petroleoquimica

    2010-07-01

    Microporous Metal-Organic Framework (MOF) adsorbents are considered an interesting option for hydrogen storage. Due to their porous nature and unusually high surface areas, these materials show an exceptional H{sub 2} uptake. Unfortunately, their interaction with H{sub 2} molecules is weak, so cryogenic temperatures are required to reach competitive H{sub 2} storage capacities. In this sense, the presence of coordinatively unsaturated and exposed metal centers in some MOF frameworks could increase the affinity for H{sub 2} through stronger metal-H{sub 2} interactions. In this preliminary work, the effect of doping a Zn{sup 2+}-MOF-74 framework with Co{sup 2+}, Cu{sup 2+} and Mg{sup 2+} on its adsorption properties for H{sub 2} has been studied. Characterization studies suggest that the samples prepared have actually the MOF-74 structure, in which the different tested heteroatom ions have been successfully incorporated. The differences in H{sub 2} adsorption at 77 K and 87 K between the MOF-74 samples doped with the mentioned divalent metal ions were discussed as a function of their free pore volume and amount of metal incorporation. (orig.)

  6. The influence of strain rate and hydrogen on the plane-strain ductility of Zircaloy cladding

    Energy Technology Data Exchange (ETDEWEB)

    Link, T.M.; Motta, A.T.; Koss, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1998-03-01

    The authors studied the ductility of unirradiated Zircaloy-4 cladding under loading conditions prototypical of those found in reactivity-initiated accidents (RIA), i.e.: near plane-strain deformation in the hoop direction (transverse to the cladding axis) at room temperature and 300 C and high strain rates. To conduct these studies, they developed a specimen configuration in which near plane-strain deformation is achieved in the gage section, and a testing methodology that allows one to determine both the limit strain at the onset of localized necking and the fracture strain. The experiments indicate that there is little effect of strain rate (10{sup {minus}3} to 10{sup 2} s{sup {minus}1}) on the ductility of unhydrided Zircaloy tubing deformed under near plane-strain conditions at either room temperature or 300 C. Preliminary experiments on cladding containing 190 ppm hydrogen show only a small loss of fracture strain but no clear effect on limit strain. The experiments also indicate that there is a significant loss of Zircaloy ductility when surface flaws are present in the form of thickness imperfections.

  7. The Influence of Change Orders leading to Disputes in Construction Phase: Contractors’ Perspective

    OpenAIRE

    Kökel, Mustafa

    2015-01-01

    ABSTRACT: Changes and Change Orders are inevitable in almost every type of project. It plays an important role in determination of quality, the overall cost and the completion time of a construction project. Thus, the Change Order process should be managed well. The Change Orders in construction are one of the main causes of conflict between the owner and the contractor. Unless a good management is applied to conflicts, they quickly turn to disputes which require resolution. The dispute resol...

  8. Influence of the initial electronic state on minima of high-order harmonic spectrum radiated from hydrogen molecular ion

    Science.gov (United States)

    Cui, Hui-Fang; Miao, Xiang-Yang

    2017-09-01

    Not Available Project supported by the National Natural Science Foundation of China (Grant No. 11404204) and the Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi Province, China.

  9. Going beyond information given: how approach versus avoidance cues influence access to higher order information

    NARCIS (Netherlands)

    Kuschel, S.; Förster, J.; Denzler, M.

    2010-01-01

    Three experiments examine the hypothesis that subtle cues of approach orientation facilitate access to higher order information, whereas subtle cues of avoidance orientation impede it. To test these predictions, in two studies, a backward-masking paradigm thought to measure access to higher order

  10. L1 Influence on the Acquisition Order of English Grammatical Morphemes

    Science.gov (United States)

    Murakami, Akira; Alexopoulou, Theodora

    2016-01-01

    We revisit morpheme studies to evaluate the long-standing claim for a universal order of acquisition. We investigate the L2 acquisition order of six English grammatical morphemes by learners from seven L1 groups across five proficiency levels. Data are drawn from approximately 10,000 written exam scripts from the Cambridge Learner Corpus. The…

  11. Influence of Conditions of Pd/SnO2 Nanomaterial Formation on Properties of Hydrogen Sensors

    Science.gov (United States)

    Sokovykh, E. V.; Oleksenko, L. P.; Maksymovych, N. P.; Matushko, I. P.

    2017-06-01

    Metal oxide sensors were created using nanosized tin dioxide obtained by a sol-gel method. Gas-sensitive layers of the sensors were impregnated with PdCl2 solutions of different concentrations to increase sensitivities of the proposed sensors. Influence of different temperature conditions of the sensor formation on the sensor properties was studied. It was found that decreasing duration of high-temperature sensor treatment prevents enlargement of particles of the gas-sensitive materials. It was shown that the sensors based on materials with smaller particle sizes showed higher sensor responses to 40 ppm H2. Obtained results were explained in terms of substantial influence of length of the common boundaries between the material particles of tin dioxide and palladium on the gas-sensitive properties of the sensors. The obtained sensors had possessed a fast response and recovery time and demonstrated stable characteristics during their long-term operation.

  12. Influence of alkaline hydrogen peroxide pre-hydrolysis on the isolation of microcrystalline cellulose from oil palm fronds.

    Science.gov (United States)

    Owolabi, Abdulwahab F; Haafiz, M K Mohamad; Hossain, Md Sohrab; Hussin, M Hazwan; Fazita, M R Nurul

    2017-02-01

    In the present study, microcrystalline cellulose (MCC) was isolated from oil palm fronds (OPF) using chemo-mechanical process. Wherein, alkaline hydrogen peroxide (AHP) was utilized to extract OPF fibre at different AHP concentrations. The OPF pulp fibre was then bleached with acidified sodium chlorite solution followed by the acid hydrolysis using hydrochloric acid. Several analytical methods were conducted to determine the influence of AHP concentration on thermal properties, morphological properties, microscopic and crystalline behaviour of isolated MCC. Results showed that the MCC extracted from OPF fibres had fibre diameters of 7.55-9.11nm. X-ray diffraction (XRD) analyses revealed that the obtained microcrystalline fibre had both celluloses I and cellulose II polymorphs structure, depending on the AHP concentrations. The Fourier transmission infrared (FTIR) analyses showed that the AHP pre-hydrolysis was successfully removed hemicelluloses and lignin from the OPF fibre. The crystallinity of the MCC was increased with the AHP concentrations. The degradation temperature of MCC was about 300°C. The finding of the present study showed that pre-treatment process potentially influenced the quality of the isolation of MCC from oil palm fronds. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. The influence of elongational flow on hydrogen bond formation and stability of the homogeneous phase of binary hydrogen- bonded polymer blends

    NARCIS (Netherlands)

    Dormidontova, Elena E.; Brinke, Gerrit ten

    2000-01-01

    Macrophase separation tendency induced by flow in binary blends of polymers capable of single hydrogen bonding between one of the chain ends is studied analytically. To describe the conformational and orientational properties of a polymer chain a simple dumbbell model is applied. It is demonstrated

  14. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides

    Science.gov (United States)

    Börries, S.; Metz, O.; Pranzas, P. K.; Bücherl, T.; Söllradl, S.; Dornheim, M.; Klassen, T.; Schreyer, A.

    2015-10-01

    In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail.

  15. The influence of charge effect on the growth of hydrogenated amorphous silicon by the hot-wire chemical vapor deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q.; Nelson, B.P.; Iwaniczko, E.; Mahan, A.H.; Crandall, R.S.; Benner, J. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    The authors observe at lower substrate temperatures that the scatter in the dark conductivity on hydrogenated amorphous silicon (a-Si:H) films grown on insulating substrates (e.g., Corning 7059 glass) by the hot-wire chemical vapor deposition technique (HWCVD) can be five orders of magnitude or more. This is especially true at deposition temperatures below 350 C. However, when the authors grow the same materials on substrates with a conductive grid, virtually all of their films have acceptable dark conductivity (< 5 {times} 10{sup {minus}10} S/cm) at all deposition temperatures below 425 C. This is in contrast to only about 20% of the materials grown in this same temperature range on insulating substrates having an acceptable dark conductivity. The authors estimated an average energy of 5 eV electrons reaching the growing surface in vacuum, and did additional experiments to see the influence of both the electron flux and the energy of the electrons on the film growth. Although these effects do not seem to be important for growing a-Si:H by HWCVD on conductive substrates, they help better understand the important parameters for a-Si:H growth, and thus, to optimize these parameters in other applications of HWCVD technology.

  16. Influence of atomic ordering on the Fe{sub 2}Nb antiferromagnetic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Vélez, G.Y., E-mail: g.y.velezcastillo@gmail.com; Alcázar, G.A. Pérez; Zamora, Ligia E.

    2014-03-15

    Fe{sub 2}Nb samples were obtained by arc melting, ordered by heat treatment, and finally disordered by means of mechanical alloying with milling times of 0.5, 1, 2 and 4 h. The ordered alloy shows only the hcp-Fe{sub 2}Nb structure which is paramagnetic at room temperature, and at low temperatures exhibits spin glass and antiferromagnetic behaviours. Mechanical alloying destroys the ordered structure and permits the formation of bcc iron-rich grains. Atomic disorder maintains the antiferromagnetic behaviour of the alloy, but increases its freezing temperature. The Néel temperature of the hcp grains is increased by the apparition of bcc grains. - Highlights: • By means of arc-melting the ordered Fe{sub 2}Nb alloy was obtained. • The ordered Fe{sub 2}Nb alloy exhibits antiferromagnetic behaviour. • Atomic disorder does not affect the antiferromagnetic phase of the alloy. • Néel temperature increases only due to the formation of the bcc Fe–Nb grains that appear during mechanical alloying.

  17. Question word-order influences on covariate effects: predicting zero-sum beliefs

    National Research Council Canada - National Science Library

    Smithson, Michael; Shou, Yiyun; Yu, Alice

    2017-01-01

    ...” and these have four permutations, whereby {X, A} and {B, Y} exchange places, and/or “more” and “less” exchange places. Smithson and Shou (Front Psychol 7:984, 2016) found that these permutations strongly influence the endorsement of such statements...

  18. The One that Does, Leads: Action Relations Influence the Perceived Temporal Order of Graspable Objects

    Science.gov (United States)

    Roberts, Katherine L.; Humphreys, Glyn W.

    2010-01-01

    Perception and action are influenced by the "possibilities for action" in the environment. Neuropsychological studies (e.g., Riddoch, Humphreys, Edwards, Baker, & Willson, 2003) have demonstrated that objects that are perceived to be interacting (e.g., a corkscrew going toward the top of a wine bottle) are perceptually integrated…

  19. Influence of hatching order and brood size on growth in jackass ...

    African Journals Online (AJOL)

    Jackass penguins Spheniscus demersus hatch two different-sized eggs asynchronously: the second-hatched chick, being, on average, 59% of the weight of the first-hatched chick on hatching. We examined the effect of hatching order on growth rates of mass, culmen length and culmen depth by comparing: (i) growth rates ...

  20. The influence of context on word order processing - an fMRI study

    DEFF Research Database (Denmark)

    Kristensen, Line Burholt; Engberg-Pedersen, Elisabeth; Nielsen, Andreas Højlund

    2013-01-01

    In languages that have subject-before-object as their canonical word order, e.g. German, English and Danish, behavioral experiments have shown more processing difficulties for object-initial clauses (OCs) than for subject-initial clauses (SCs). For processing of OCs in such languages, neuroimagin...

  1. Influence of hatching order and brood size on growth in jackass ...

    African Journals Online (AJOL)

    1991-06-26

    Jun 26, 1991 ... Jackass penguins Spheniscus demersus hatch two different-sized eggs asynchronously: the second-hatched chick, being, on average, Sgo,{, of the weight of the first-hatched chick on hatching. We examined the effect of hatching order on growth rates of mass, culmen length and culmen depth by ...

  2. Order of Stimulus Presentation Influences Children's Acquisition in Receptive Identification Tasks

    Science.gov (United States)

    Petursdottir, Anna Ingeborg; Aguilar, Gabriella

    2016-01-01

    Receptive identification is usually taught in matching-to-sample format, which entails the presentation of an auditory sample stimulus and several visual comparison stimuli in each trial. Conflicting recommendations exist regarding the order of stimulus presentation in matching-to-sample trials. The purpose of this study was to compare acquisition…

  3. Influence of the concentration of borohydride towards hydrogen production and escape for borohydride oxidation reaction on Pt and Au electrodes - experimental and modelling insights

    Science.gov (United States)

    Olu, Pierre-Yves; Bonnefont, Antoine; Braesch, Guillaume; Martin, Vincent; Savinova, Elena R.; Chatenet, Marian

    2018-01-01

    The Borohydride Oxidation Reaction (BOR), the anode reaction in a Direct borohydride fuel cell (DBFC), is complex and still poorly understood, which impedes the development and deployment of the DBFC technology. In particular, no practical electrocatalyst is capable to prevent gaseous hydrogen generation and escape from its anode upon operation, which lowers the fuel-efficiency of the DBFC and raises safety issues in operation. The nature of the anode electrocatalysts strongly influences the hydrogen escape characteristics of the DBFC, which demonstrates how important it is to isolate the BOR mechanism in conditions relevant to DBFC operation. In this paper, from a selected literature review and BOR experiments performed in differential electrochemical mass spectrometry (DEMS) in a wide range of NaBH4 concentration (5-500 mM), a microkinetic model of the BOR for both Pt and Au surfaces is proposed; this model takes into account the hydrogen generation and escape.

  4. Applied potentials regulate recovery of residual hydrogen from acid-rich effluents: Influence of biocathodic buffer capacity over process performance.

    Science.gov (United States)

    Nikhil, G N; Venkata Mohan, S; Swamy, Y V

    2015-01-01

    An absolute biological microbial electrolysis cell (MEC) was operated for a prolonged period under different applied potentials (Eapp, -0.2V to -1.0V) and hydrogen (H2) production was observed using acid-rich effluent. Among these potentials, an optimal voltage of -0.6 V influenced the biocathode by which maximum H2 production of 120 ± 9 ml was noticed. This finding was corroborated with dehydrogenase activity (1.8 ± 0.1 μg/ml) which is the key enzyme for H2 production. The in situ biocathode regulated buffer overpotentials which was remarkably observed by the change in peak heights of dissociation value (pKa) from the titration curve. Substrate degradation analysis gave an estimate of coulombic efficiency of about 72 ± 5% when operated at optimal voltage. Evidently, the electron transfer from solid carbon electrode to biocathode was analyzed by cyclic voltammetry and its derivatives showed the involvement of redox mediators. Despite, the MEC endures certain activation overpotentials which were estimated from the Tafel slope analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Influence of order-disorder transitions on oxygen permeability through selected nonstoichiometric perovskite-type oxides

    NARCIS (Netherlands)

    Kruidhof, H.; Bouwmeester, Henricus J.M.; van Doorn, R.H.E.; Burggraaf, A.J.

    1993-01-01

    New results on the oxygen permeability of perovskite-type oxides SrCo0.8B'0.2O3¿¿ (with B'=Cr, Fe, Co and Cu) and La0.6Sr0.4CoO3¿¿ are presented. The occurrence of order-disorder transitions at elevated temperatures (790¿940°C) in these phases has been confirmed by DSC measurements and, in some

  6. Factors Influencing the Incidence of Obesity in Australia: A Generalized Ordered Probit Model

    OpenAIRE

    Avsar, Gulay; Ham, Roger; Tannous, W. Kathy

    2017-01-01

    The increasing health costs of and the risks factors associated with obesity are well documented. From this perspective, it is important that the propensity of individuals towards obesity is analyzed. This paper uses longitudinal data from the Household Income and Labour Dynamics in Australia (HILDA) Survey for 2005 to 2010 to model those variables which condition the probability of being obese. The model estimated is a random effects generalized ordered probit, which exploits two sources of ...

  7. Influence of Exercise Order on Electromyographic Activity During Upper Body Resistance Training

    Directory of Open Access Journals (Sweden)

    Soncin Rafael

    2014-12-01

    Full Text Available The purpose of this study was to investigate the effects of exercise order on electromyographic activity in different muscle groups among youth men with experience in strength training. Three sets of 8 RM were performed of each exercise in two sequences order: (a sequence A: bench press, chest fly, shoulder press, shoulder abduction, close grip bench press and lying triceps extension; (b sequence B: the opposite order. The electromyographic activity was analyzed in the sternocostal head of the pectoralis major, anterior deltoid, and long head triceps brachii, normalized for maximal voluntary isometric contraction. The muscles activity of the sternocostal head of the pectoralis major, anterior deltoid, and long head triceps brachii showed significant interaction between sequence and exercise. The sternocostal head of the pectoralis major showed considerably higher activity in sequence A (100.13 ± 13.56% than sequence B (81.47 ± 13.09% for the chest fly. The anterior deltoid showed significantly higher electromyographic activity in sequence B (86.81 ± 40.43% than sequence A (66.15 ± 22.02% for the chest fly, whereas for the lying triceps extension, the electromyographic activity was significantly higher in sequence A (53.89 ± 27.09% than sequence B (34.32 ± 23.70%. For the long head triceps brachii, only the shoulder press showed differences between sequences (A = 52.43 ± 14.64 vs. B = 38.53 ± 16.26. The present study showed that the exercise order could modify the training results even though there was no alteration in volume and intensity of the exercise. These changes may result in different training adaptations.

  8. Influence of birth order, birth weight, colostrum and serum immunoglobulin G on neonatal piglet survival.

    Science.gov (United States)

    Cabrera, Rafael A; Lin, Xi; Campbell, Joy M; Moeser, Adam J; Odle, Jack

    2012-12-23

    Intake of colostrum after birth is essential to stimulate intestinal growth and function, and to provide systemic immunological protection via absorption of Immunoglobulin G (IgG). The birth order and weight of 745 piglets (from 75 litters) were recorded during a one-week period of farrowing. Only pigs weighing greater than 0.68 kg birth weight were chosen for the trial. Sow colostrum was collected during parturition, and piglets were bled between 48 and 72 hours post-birth. Piglet serum IgG and colostral IgG concentrations were determined by radial immunodiffusion. Sow parity had a significant (P birth order accounted for another 4% of the variation observed in piglet serum IgG concentration (P birth weight had no detectable effect. Piglet serum IgG concentration had both a linear (P Birth order had no detectable effect on survival, but birth weight had a positive linear effect (P birth had a 68% survival rate, and those weighing 1.6 kg (n = 158) had an 89% survival. We found that the combination of sow colostrum IgG concentration and birth order can account for 10% of the variation of piglet serum IgG concentration and that piglets with less than 1,000 mg/dl IgG serum concentration and weight of 0.9 kg at birth had low survival rate when compared to their larger siblings. The effective management of colostrum uptake in neonatal piglets in the first 24 hrs post-birth may potentially improve survival from birth to weaning.

  9. The Intramolecular Pressure and the Extension of the Critical Point’s Influence Zone on the Order Parameter

    Directory of Open Access Journals (Sweden)

    Jose Luis Rivera

    2015-01-01

    Full Text Available The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone covers up to hundreds of degrees below the critical temperature. Here we show that, for ethane, the experimental critical influence zone covers a wide zone of tens of degrees (below the critical temperature down to a transition temperature, at which the apparent critical influence zone vanishes, and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase, using a simple molecular potential. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, Molecular Dynamics simulations reveal that the experimentally observed wide extension of the critical influence zone is the result of a vapor-like effect due to low bulk liquid phase densities.

  10. Educating Grade 6 students for higher-order thinking and its influence on creativity

    Directory of Open Access Journals (Sweden)

    Wajeeh Daher

    2017-04-01

    Full Text Available Educating students for higher-order thinking provides them with tools that turn them into more critical thinkers. This supports them in overcoming life problems that they encounter, as well as becoming an integral part of the society. This students’ education is attended to by educational organisations that emphasise the positive consequences of educating students for higher-order thinking, including creative thinking. One way to do that is through educational programmes that educate for higher-order thinking. One such programme is the Cognitive Research Trust (CoRT thinking programme. The present research intended to examine the effect of the participation of Grade 6 students in a CoRT programme on their creative thinking. Fifty-three students participated in the research; 27 participated in a CoRT programme, while 26 did not participate in such programme. The ANCOVA test showed that the students who participated in the CoRT programme outperformed significantly, in creative thinking, the students who did not. Moreover, the students in the CoRT programme whose achievement scores were between 86 and 100 outperformed significantly the other achievement groups of students. Furthermore, students with reported high ability outperformed significantly the other ability groups of students. The results did not show statistically significant differences in students’ creativity attributed to gender.

  11. An effective utilization management strategy by dual approach of influencing physician ordering and gate keeping.

    Science.gov (United States)

    Elnenaei, Manal O; Campbell, Samuel G; Thoni, Andrea J; Lou, Amy; Crocker, Bryan D; Nassar, Bassam A

    2016-02-01

    There is increasing recognition of the importance of appropriate laboratory test utilization. We investigate the effect of a multifaceted educational approach that includes physician feedback on individual test ordering, in conjunction with targeted restriction, on the utilization of selected laboratory tests. Scientific evidence was compiled on the usefulness and limitations of tests suspected of being over utilized in our laboratories. A variety of approaches were used to deliver education on each of the targeted tests, with greater focus on primary care physicians (PCPs). Feedback on requesting behavior of these tests was also communicated to the latter group which included an educational component. Laboratory based restriction of testing was also exercised, including the unbundling of our electrolyte panel. PCP requesting patterns for the selected tests were found to be markedly skewed. The interventions implemented over the study period resulted in a substantial 51% reduction in overall ordering of five of the targeted tests equating to an annual marginal cost saving of $60,124. Unbundling of the electrolyte panel resulted in marginal cost savings that equated annually to $42,500 on chloride and $48,000 on total CO2. A multifaceted educational approach combined with feedback on utilization and laboratory driven gate-keeping significantly reduced the number of laboratory tests suspected of being redundant or unjustifiably requested. Laboratory professionals are well positioned to manage demand on laboratory tests by utilizing evidence base in developing specific test ordering directives and gate-keeping rules. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  12. Influence of hydrogen cations on kinetics and equilibria of heavy-metal sorption by algae-sorption of copper cations by the algaPalmaria palmata(Linnaeus) Weber & Mohr (Rhodophyta).

    Science.gov (United States)

    Kłos, Andrzej; Rajfur, Małgorzata

    2013-01-01

    The influence of hydrogen cations on kinetics and equilibria of sorption of copper cations by the marine alga Palmaria palmata (Linnaeus) Weber & Mohr was studied under static conditions. The competitive effect of the H + cations is described, which influenced the uncertainty of evaluation of the alga sorption capacity. Under static conditions, the variation of the Cu 2+ /H + concentration ratio during sorption was found nonmonotonic. The Langmuir isotherm model was used to determine the sorption capacity of the alga, namely 12.4 mg g -1 of dry algae mass. A similar value was determined from the kinetic parameters of the ionic exchange which is considered a pseudo-second-order chemical reaction. The consistent results indicated that the mathematical models used correctly described the equilibria and kinetics of the ionic exchange between algae and solutions.

  13. A superconductor to superfluid phase transition in liquid metallic hydrogen.

    Science.gov (United States)

    Babaev, Egor; Sudbø, Asle; Ashcroft, N W

    2004-10-07

    Although hydrogen is the simplest of atoms, it does not form the simplest of solids or liquids. Quantum effects in these phases are considerable (a consequence of the light proton mass) and they have a demonstrable and often puzzling influence on many physical properties, including spatial order. To date, the structure of dense hydrogen remains experimentally elusive. Recent studies of the melting curve of hydrogen indicate that at high (but experimentally accessible) pressures, compressed hydrogen will adopt a liquid state, even at low temperatures. In reaching this phase, hydrogen is also projected to pass through an insulator-to-metal transition. This raises the possibility of new state of matter: a near ground-state liquid metal, and its ordered states in the quantum domain. Ordered quantum fluids are traditionally categorized as superconductors or superfluids; these respective systems feature dissipationless electrical currents or mass flow. Here we report a topological analysis of the projected phase of liquid metallic hydrogen, finding that it may represent a new type of ordered quantum fluid. Specifically, we show that liquid metallic hydrogen cannot be categorized exclusively as a superconductor or superfluid. We predict that, in the presence of a magnetic field, liquid metallic hydrogen will exhibit several phase transitions to ordered states, ranging from superconductors to superfluids.

  14. Second-order conditioning and conditioned inhibition: influences of speed versus accuracy on human causal learning.

    Science.gov (United States)

    Lee, Jessica C; Livesey, Evan J

    2012-01-01

    In human causal learning, excitatory and inhibitory learning effects can sometimes be found in the same paradigm by altering the learning conditions. This study aims to explore whether learning in the feature negative paradigm can be dissociated by emphasising speed over accuracy. In two causal learning experiments, participants were given a feature negative discrimination in which the outcome caused by one cue was prevented by the addition of another. Participants completed training trials either in a self-paced fashion with instructions emphasising accuracy, or under strict time constraints with instructions emphasising speed. Using summation tests in which the preventative cue was paired with another causal cue, participants in the accuracy groups correctly rated the preventative cue as if it reduced the probability of the outcome. However, participants in the speed groups rated the preventative cue as if it increased the probability of the outcome. In Experiment 1, both speed and accuracy groups later judged the same cue to be preventative in a reasoned inference task. Experiment 2 failed to find evidence of similar dissociations in retrospective revaluation (release from overshadowing vs. mediated extinction) or learning about a redundant cue (blocking vs. augmentation). However in the same experiment, the tendency for the accuracy group to show conditioned inhibition and the speed group to show second-order conditioning was consistent even across sub-sets of the speed and accuracy groups with equivalent accuracy in training, suggesting that second-order conditioning is not merely a consequence of poorer acquisition. This dissociation mirrors the trade-off between second-order conditioning and conditioned inhibition observed in animal conditioning when training is extended.

  15. Second-order conditioning and conditioned inhibition: influences of speed versus accuracy on human causal learning.

    Directory of Open Access Journals (Sweden)

    Jessica C Lee

    Full Text Available In human causal learning, excitatory and inhibitory learning effects can sometimes be found in the same paradigm by altering the learning conditions. This study aims to explore whether learning in the feature negative paradigm can be dissociated by emphasising speed over accuracy. In two causal learning experiments, participants were given a feature negative discrimination in which the outcome caused by one cue was prevented by the addition of another. Participants completed training trials either in a self-paced fashion with instructions emphasising accuracy, or under strict time constraints with instructions emphasising speed. Using summation tests in which the preventative cue was paired with another causal cue, participants in the accuracy groups correctly rated the preventative cue as if it reduced the probability of the outcome. However, participants in the speed groups rated the preventative cue as if it increased the probability of the outcome. In Experiment 1, both speed and accuracy groups later judged the same cue to be preventative in a reasoned inference task. Experiment 2 failed to find evidence of similar dissociations in retrospective revaluation (release from overshadowing vs. mediated extinction or learning about a redundant cue (blocking vs. augmentation. However in the same experiment, the tendency for the accuracy group to show conditioned inhibition and the speed group to show second-order conditioning was consistent even across sub-sets of the speed and accuracy groups with equivalent accuracy in training, suggesting that second-order conditioning is not merely a consequence of poorer acquisition. This dissociation mirrors the trade-off between second-order conditioning and conditioned inhibition observed in animal conditioning when training is extended.

  16. Attitudes towards assisted dying are influenced by question wording and order: a survey experiment.

    Science.gov (United States)

    Magelssen, Morten; Supphellen, Magne; Nortvedt, Per; Materstvedt, Lars Johan

    2016-04-27

    Surveys on attitudes towards assisted dying play an important role in informing public debate, policy and legislation. Unfortunately, surveys are often designed with insufficient attention to framing effects; that is, effects on the respondents' stated attitudes caused by question wording and context. The purpose of this study was to demonstrate and measure such framing effects. Survey experiment in which an eight-question survey on attitudes towards assisted dying was distributed to Norwegian citizens through a web-based panel. Two variations of question wording as well as two variations of question order were employed. Respondents were randomized to receive one of four questionnaire versions. Three thousand and fifty responses were received. There were moderate to large question wording and question order effects. A majority of Norwegian citizens favour the legalization of assisted dying for patients with terminal or chronic disease. Stakeholders in the assisted dying debate need to acknowledge potential framing effects, and accordingly should interpret survey results with caution. The same holds for researchers who conduct attitude surveys in the field of bioethics.

  17. Influence of squeeze film damping on the higher-order modes of clamped–clamped microbeams

    KAUST Repository

    Alcheikh, Nouha

    2016-05-06

    This paper presents an experimental study and a finite-element analysis of the effect of squeeze film damping on the resonance frequency and quality factor of the higher-order flexure vibrations modes of clamped-clamped microbeams. Viscoelastic and silicon nitride microbeams are fabricated and are electrostatically actuated by various electrode configurations to trigger the first, second, and third modes. The damping characteristic and the resonance frequency of these modes are examined for a wide range of gas pressure and electrostatic voltage loads. The results of the silicon nitride beams and viscoelastic beams are compared. It is found that the intrinsic material loss is the major dissipation mechanism at low pressure for the viscoelastic microbeams, significantly limiting their quality factor. It is also found that while the silicon nitride beams show higher quality factors at the intrinsic and molecular regimes of pressure, due to their low intrinsic loss, their quality factors near atmospheric pressure are lower than those of the viscoelastic microbeams. Further, the higher-order modes of all the beams show much higher quality factors at atmospheric pressure compared to the first mode, which could be promising for operating such resonators in air. Experimental results and finite element model simulations show good agreement for resonance frequency and quality factor for the three studied modes. © 2016 IOP Publishing Ltd.

  18. Influence of Simple Electrolytes on the Orientational Ordering of Thermotropic Liquid Crystals at Aqueous Interfaces

    Science.gov (United States)

    Carlton, Rebecca J.; Gupta, Jugal K.; Swift, Candice L.; Abbott, Nicholas L.

    2011-01-01

    We report orientational anchoring transitions at aqueous interfaces of a water-immiscible, thermotropic liquid crystal (LC; nematic phase of 4′-pentyl-4-cyanobiphenyl) that are induced by changes in pH of the aqueous solution and the addition of simple electrolytes (NaCl) to the aqueous phase. Whereas measurements of the zeta potential on the aqueous side of the interface of LC-in-water emulsions prepared with 5CB confirm pH-dependent formation of an electrical double layer extending into the aqueous phase, quantification of the orientational ordering of the LC leads to the proposition that an electrical double layer is also formed on the LC-side of the interface with an internal electric field that drives the LC anchoring transition. Further support for this conclusion is obtained from measurements of the dependence of LC ordering on pH and ionic strength, as well as a simple model based on the Poisson-Boltzmann equation from which we calculate the contribution of an electrical double layer to the orientational anchoring energy of the LC. Overall, the results presented herein provide new fundamental insights into ionic phenomena at LC-aqueous interfaces, and expand the range of solutes known to cause orientational anchoring transitions at LC-aqueous interfaces beyond previously examined amphiphilic adsorbates. PMID:22106820

  19. Factors Influencing the Incidence of Obesity in Australia: A Generalized Ordered Probit Model

    Directory of Open Access Journals (Sweden)

    Gulay Avsar

    2017-02-01

    Full Text Available The increasing health costs of and the risks factors associated with obesity are well documented. From this perspective, it is important that the propensity of individuals towards obesity is analyzed. This paper uses longitudinal data from the Household Income and Labour Dynamics in Australia (HILDA Survey for 2005 to 2010 to model those variables which condition the probability of being obese. The model estimated is a random effects generalized ordered probit, which exploits two sources of heterogeneity; the individual heterogeneity of panel data models and heterogeneity across body mass index (BMI categories. The latter is associated with non-parallel thresholds in the generalized ordered model, where the thresholds are functions of the conditioning variables, which comprise economic, social, and demographic and lifestyle variables. To control for potential predisposition to obesity, personality traits augment the empirical model. The results support the view that the probability of obesity is significantly determined by the conditioning variables. Particularly, personality is found to be important and these outcomes reinforce other work examining personality and obesity.

  20. Factors Influencing the Incidence of Obesity in Australia: A Generalized Ordered Probit Model.

    Science.gov (United States)

    Avsar, Gulay; Ham, Roger; Tannous, W Kathy

    2017-02-10

    The increasing health costs of and the risks factors associated with obesity are well documented. From this perspective, it is important that the propensity of individuals towards obesity is analyzed. This paper uses longitudinal data from the Household Income and Labour Dynamics in Australia (HILDA) Survey for 2005 to 2010 to model those variables which condition the probability of being obese. The model estimated is a random effects generalized ordered probit, which exploits two sources of heterogeneity; the individual heterogeneity of panel data models and heterogeneity across body mass index (BMI) categories. The latter is associated with non-parallel thresholds in the generalized ordered model, where the thresholds are functions of the conditioning variables, which comprise economic, social, and demographic and lifestyle variables. To control for potential predisposition to obesity, personality traits augment the empirical model. The results support the view that the probability of obesity is significantly determined by the conditioning variables. Particularly, personality is found to be important and these outcomes reinforce other work examining personality and obesity.

  1. Numerical study of Potts models with aperiodic modulations: influence on first-order transitions

    Science.gov (United States)

    Branco, Nilton; Girardi, Daniel

    2012-02-01

    We perform a numerical study of Potts models on a rectangular lattice with aperiodic interactions along one spatial direction. The number of states q is such that the transition is a first-order one for the uniform model. The Wolff algorithm is employed, for many lattice sizes, allowing for a finite-size scaling analyses to be carried out. Three different self-dual aperiodic sequences are employed, such that the exact critical temperature is known: this leads to precise results for the exponents. We analyze models with q=6 and 15 and show that the Harris-Luck criterion, originally introduced in the study of continuous transitions, is obeyed also for first-order ones. The new universality class that emerges for relevant aperiodic modulations depends on the number of states of the Potts model, as obtained elsewhere for random disorder, and on the aperiodic sequence. We determine the occurrence of log-periodic behavior, as expected for models with aperiodic modulated interactions.

  2. Influence of Anodic Conditions on Self-ordered Growth of Highly Aligned Titanium Oxide Nanopores

    Directory of Open Access Journals (Sweden)

    Hernández-Vélez M

    2007-01-01

    Full Text Available AbstractSelf-aligned nanoporous TiO2templates synthesized via dc current electrochemical anodization have been carefully analyzed. The influence of environmental temperature during the anodization, ranging from 2 °C to ambient, on the structure and morphology of the nanoporous oxide formation has been investigated, as well as that of the HF electrolyte chemical composition, its concentration and their mixtures with other acids employed for the anodization. Arrays of self-assembled titania nanopores with inner pores diameter ranging between 50 and 100 nm, wall thickness around 20–60 nm and 300 nm in length, are grown in amorphous phase, vertical to the Ti substrate, parallel aligned to each other and uniformly disordering distributed over all the sample surface. Additional remarks about the photoluminiscence properties of the titania nanoporous templates and the magnetic behavior of the Ni filled nanoporous semiconductor Ti oxide template are also included.

  3. Higher order influences on evaluative priming: Processing styles moderate congruity effects.

    Science.gov (United States)

    Alexopoulos, Theodore; Lemonnier, Aurore; Fiedler, Klaus

    2017-01-01

    A growing body of research challenges the automaticity of evaluative priming (EP). The present research adds to this literature by suggesting that EP is sensitive to processing styles. We relied on previous research showing that EP is determined by the extent to which the prime and the target events on a given trial are processed as a unified compound. Here, we further hypothesised that processing styles encouraging the inclusion of the prime to the target episode support congruity effects, whereas processing styles that enhance the exclusion of the prime from the target episode interrupt (or reverse) these effects. In Experiment 1, a preceding similarity search task produced a congruity effect, whereas a dissimilarity search task eliminated and (non-significantly) reversed this effect. In Experiments 2 and 3, we replicated and extended these findings using a global/local processing manipulation. Overall, these findings confirm that EP is flexible, open to top-down influences and strategic regulation.

  4. Influence of intramolecular hydrogen bonding interaction on the molecular properties of N-p-tolyl-5-oxo pyrrolidine-3-carboxylic acid: A theoretical and experimental study

    Science.gov (United States)

    Muthuraja, P.; Shanmugavadivu, T.; Joselin Beaula, T.; Bena Jothy, V.; Dhandapani, M.

    2018-01-01

    N-p-tolyl-5-oxo pyrrolidine-3-carboxylic acid (TOPCA) was synthesized by Michael addition-cyclo condensation. The molecular structure of TOPCA was optimized by B3LYP method with 6-311G(d,p) and aug-cc-pVDZ (Dunning) basis sets as well as CAM-B3LYP method with 6-311G(d,p) basis set. In addition, MEP, CHELPG and NBO analyses were carried out to understand the influence of hydrogen bonding interactions. The molecular structure of TOPCA is governed by intramolecular hydrogen bonding interactions (Csbnd H…O) which influence charge transfer in TOPCA. The Csbnd H…O interactions stimulate the emission property of TOPCA excited at 380 nm. Intramolecular H- bonding and charge transfer induce the second hyperpolarizability in TOPCA.

  5. ANALYSIS OF PUBLIC COURT-ORDERED-DEBT DISCLOSURE: INFLUENCE OF LEGISLATION AND FUNDAMENTALS OF ACCOUNTING THEORY

    Directory of Open Access Journals (Sweden)

    Lucas Oliveira Gomes Ferreira

    2012-03-01

    Full Text Available The purpose of the present study is to analyze the accounting disclosure of judicial payments warrants (precatórios, issued when governmental entities are found liable for pecuniary awards in lawsuits according to accounting theory, and to verify if the current legislation interferes in the accounting treatment of these instruments. In this sense, we performed a documental and literature review about the legal framework and accounting procedures adopted, as well gathered data from the National Treasury Secretariat Data Collection System (SISTN in the period 2004-2009 and consulted a study carried out by the Supreme Court (STF in 2004. The study’s justification is based on the perception that over than a half of judicial payment warrants are not registered in the public accounts. Consequently, whereas these warrants (i vested rights of the plaintiffs and (ii debts of the public entity, the lack of accounting disclosure jeopardizes both the beneficiary, whose right is not reflected in the public accounts, thus casting doubt on the expectation to receive payment, and government managers and society, who do not have reliable information that allows effective management. The innovation of this paper consists of discussing identification of the appropriate moment of the generating event of the underlying debts and the proposal of disclosure considering the risk classification. In conclusion, the influence of the current legislation and the failure to observe accounting fundamentals are among the likely factors that have affected the proper accounting of judicial payment warrants within the Brazilian public administration.

  6. Hydrogen Passivation of Interstitial Zn Defects in Heteroepitaxial InP Cell Structures and Influence on Device Characteristics

    Science.gov (United States)

    Ringel, S. A.; Chatterjee, B.

    2004-01-01

    Hydrogen passivation of heteroepitaxial InP solar cells is of recent interest for deactivation of dislocations and other defects caused by the cell/substrate lattice mismatch that currently limit the photovoltaic performance of these devices. In this paper we present strong evidence that, in addition to direct hydrogen-dislocation interactions, hydrogen forms complexes with the high concentration of interstitial Zn defects present within the p(+) Zn-doped emitter of MOCVD-grown heteroepitaxial InP devices, resulting in a dramatic increase of the forward bias turn-on voltage by as much as 280 mV, from 680 mV to 960 mV. This shift is reproducible and thermally reversible and no such effect is observed for either n(+)p structures or homoepitaxial p(+)n structures grown under identical conditions. A combination of photoluminescence (PL), electrochemical C-V dopant profiling, SIMS and I-V measurements were performed on a set of samples having undergone a matrix of hydrogenation and post-hydrogenation annealing conditions to investigate the source of this voltage enhancement and confirm the expected role of interstitial Zn and hydrogen. A precise correlation between all measurements is demonstrated which indicates that Zn interstitials within the p(+) emitter and their interaction with hydrogen are indeed responsible for this device behavior.

  7. Influence of higher order need strenght and job characteristics on job performance

    Directory of Open Access Journals (Sweden)

    C. J. H. Blignaut

    1975-11-01

    Full Text Available Contemporary theories of work motivation are classified according to (1 those based on the underlying assumption that all individuals posses higher level need, are capable of satisfying and will indeed satisfy such needs provided the job situation incorporates the conditions or characteristics that make satisfaction possible and (2 those theories suggesting that an individual may or may not be motivated by certain job characteristics depending on whether he in fact has specific (higher level needs to be fulfilled and whether he views the job situation as conductive to need satisfaction. 126 Subjects employed by a chemical industry took part in an experiment designed to test the basic assumptions underlying the aforementioned theories. Data relating to higher order need satisfaction, the psychological value of job content and job performance served as input to a 2X2 factorial analysis. Results indicate that only the psychological value of job content represented a significant source of variation (p is smaller as ,01 - a finding which favours category (1 theories to a large extent. No significant interaction between the latter source of variation and higher order need satisfaction could be found.Opsomming Kontemporêre motiveringsteorieë in die Bedryfsielkunde word geklassifiseer in twee groepe naamlik (1 dié wat berus op die basiese aanname dat alle werknemers hoëvlak behoeftes het en die bevrediging daarvan sal nastreef solank die inhoud van die werk dit moontlik maak en (2 dié wat op die aanname berus dat sielkundig gunstige werksinhoud waarskynlik hoëvlak behoeftebevrediging tot gevolg sal hê, afhangende van hoe die individu die werksituasie waarneem. 126 Werknemers in 'n Suid-Afrikaanse chemiese nywerheid is by 'n eksperiment betrek waarin bogenoemde basiese aannames teenoor mekaar gestel is. Data ten opsigte van die sielkundige waarde van werksinhoud, hoëvlak behoeftebevrediging en werksprestasie dien as inset tot 'n 2x2 faktoriale

  8. Trunk rotation affects temporal order judgments with direct saccades: Influence of handedness.

    Science.gov (United States)

    Paschke, Kerstin; Kagan, Igor; Wüstenberg, Torsten; Bähr, Mathias; Wilke, Melanie

    2015-12-01

    Manipulation of the trunk midline has been shown to improve visuospatial performance in patients with unilateral visual neglect. The goal of the present study was to disentangle motor and perceptual components of egocentric midline manipulations and to investigate the contribution of individual hand preference. Two versions of visual temporal order judgment (TOJ) tasks were tested in healthy right- and left-handed subjects while trunk rotation was varied. In the congruent version, subjects were required to execute a saccade to the first of two horizontal stimuli presented with different stimulus onset asynchronies (SOA). In the incongruent version, subjects were required to perform a vertical saccade to a pre-learned color target, thereby dissociating motor response from the perceptual stimulus location. The main findings of this study are a trunk rotation and response direction specific impact on temporal judgments in form of a prior entry bias for right hemifield stimuli during rightward trunk rotation, but only in the congruent task. This trunk rotation-induced spatial bias was most pronounced in left-handed participants but had the same sign in the right-handed group. Results suggest that egocentric midline shifts in healthy subjects induce a spatially-specific motor, but not a perceptual, bias and underline the importance of taking individual differences in functional laterality such as handedness and mode of perceptual report into account when evaluating effects of trunk rotation in either healthy subjects or neurological patients. Copyright © 2015. Published by Elsevier Ltd.

  9. Influence of aspect ratio and anisotropy distribution in ordered CoNi nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, W.O., E-mail: wrosa@cbpf.br [Depto. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007-Oviedo (Spain); Centro Brasileiro de Pesquisas Fisicas, R. Dr. Xavier Sigaud, 150 - 22290-180, Rio de Janeiro (Brazil); Vivas, L.G. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049-Madrid (Spain); Pirota, K.R. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, 13083-970-Campinas (Brazil); Asenjo, A.; Vazquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049-Madrid (Spain)

    2012-11-15

    The size effects on magnetic properties of nanowires arrays were studied varying the nanowires diameter and maintaining the same periodicity among them, for two different nominal compositions of Co and Ni in the alloy form. The competition among magnetocrystalline and shape anisotropies changes drastically from smallest to biggest diameters altering the easy axis direction. In the case of 75% of Co in alloy, experimental values of the effective anisotropy constant (K{sub eff}) vary from positive to negative depending on the diameter, which means a reversal of the easy axis direction. For 50% of Co the shape anisotropy dominates over the magnetocrystalline for all studied diameters. - Highlights: Black-Right-Pointing-Pointer Highly ordered CoNi nanowire alloys have been produced by electrodeposition. Black-Right-Pointing-Pointer Electrolyte temperature ensures the deposition of CoNi alloys instead of Co and Ni segregated. Black-Right-Pointing-Pointer A competition between shape and magnetocrystalline anisotropies determines the direction of the easy magnetization axis. Black-Right-Pointing-Pointer Analysis of the effective anisotropy gives us information respect to the easy axis modification.

  10. Efficient photocatalytic degradation of tetrabromodiphenyl ethers and simultaneous hydrogen production by TiO2-Cu2O composite films in N2 atmosphere: Influencing factors, kinetics and mechanism.

    Science.gov (United States)

    Hu, Zhe; Wang, Xi; Dong, Haitai; Li, Shangyi; Li, Xukai; Li, Laisheng

    2017-10-15

    TiO2-Cu2O photocatalyst composite film with a heterostructure was synthesized on a copper substrate for 2,2',4,4'-tetrabromodiphenyl ether (BDE47) reduction. First, Cu2O film was synthesized by the electrochemical deposition method, and then TiO2 was coated on the surface of the Cu2O film. The morphology, surface chemical composition and optical characteristics of TiO2-Cu2O film were characterized. The degradation efficiency of BDE47 and hydrogen production by TiO2-Cu2O films was higher than those by pure TiO2 or Cu2O films. The highest BDE47 degradation efficiency of 90% and hydrogen production of 12.7mmolLliq(-1) after 150min were achieved by 67%TiO2-Cu2O films. The influencing factors were investigated in terms of film component, solvent condition, and initial pH. A kinetics study demonstrated that BDE47 degradation followed a pseudo-first-order model. Photocatalytic apparent reaction rate constant of BDE47 by TiO2-Cu2O films was 0.0070min(-1), which was 3.3 times of that by directly photolysis process. During photocatalytic debrmination process, the photogenerated holes were reserved in the valance band of Cu2O to oxidize methanol. Meanwhile, the partial photogenerated electrons transferred to the conduction band of TiO2 and directly eliminated the ortho-Br of BDE47 and yielded BDE28 and BDE15. The other partial photogenerated electrons reduced protons (H(+)) to form atomic hydrogen (H°), which could substitute the para-Br of BDE47 and generated BDE17 and produce hydrogen. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. The chaos and order in human ECG under the influence of the external perturbations

    Science.gov (United States)

    Ragulskaya, Maria; Valeriy, Pipin

    model reconstruction of the individual cardiac beat. It is found that the positions of the stationary points of the typical ECG attractor are in vicinities of Q and T waves. Additionally, we find that the stiffness of the beat is important for the general stability of ECG. The given results agues for the increase the relative disorder of the human cardiac system under external perturbations due to changes in the space weather and climatic factors. Also, the results of monitoring show that cardiac system can be stabilized by "internal" (physical) stress. The given difference in the cardiac sys-tem behavior under the different types of stress is obtained in the earth labaratory conditions. However, it should be considered as important factors influencing on the health of cosmonauts during the space missions, as well.

  12. Beyond the genetic basis of sensation seeking: The influence of birth order, family size and parenting styles

    Directory of Open Access Journals (Sweden)

    Feij, Jan A,

    2010-12-01

    Full Text Available Genetic analyses of sensation seeking have shown fairly high heritabilities for measures of this trait. However, 40 to 60% of the variance remains unexplained by genetic factors. This longitudinal study examines the influence of characteristics of the family environment -- birth order, family size, socio-economic status and parenting styles -- on two dimensions of sensation seeking: disinhibition and boredom susceptibility. Previous research has shown that these dimensions load on the same factor, are related to biologically based impulsive disorders, and have a common genetic basis. Questionnaire and biographical data obtained from 532 female and 479 male young adults (age between 18 and 30 years were analyzed using structural modeling. The results show that participants who experienced little parental care and much control were more likely to have high scores on disinhibition and boredom susceptibility. It appears that these family factors may partly explain the previously reported effects of birth order and family size on sensation seeking.

  13. Hydrogen CARS thermometry in H2-N2 mixtures at high pressure and medium temperatures: influence of linewidths models

    Science.gov (United States)

    Hussong, J.; Stricker, W.; Bruet, X.; Joubert, P.; Bonamy, J.; Robert, D.; Michaut, X.; Gabard, T.; Berger, H.

    In order to improve the accuracy of H2 CARS thermometry, H2 Q-branch CARS spectra have been recorded for various H2-N2 mixtures in a high-pressure cell at different pressures and temperatures (up to 40 bar and 875 K). Due to the low spectral resolution of broadband CARS experiments, the relevant spectral lineshape factor is the linewidth ratio Γ(Q(3))/Γ(Q(1)), since Q(1) and Q(3) are the most intense lines of the Q-branch spectrum in this temperature range. For the first time, the speed-inhomogeneous effects are accounted for in the simulation of the CARS profiles. The evaluated temperatures are in good agreement with reference values obtained by thermocouples. The specific role on the accuracy of H2 CARS thermometry of the speed inhomogeneity is carefully analyzed, in connection with the influence of the nitrogen concentration.

  14. The Influence of Injection Timing on Performance Characteristics of Diesel Engine Using Jatropha Biodiesel with and without Partial Hydrogenation

    Directory of Open Access Journals (Sweden)

    Rizqon Fajar

    2014-07-01

    Full Text Available Experimental research has been conducted to investigate the effects of blend of hydrogenated and unhydrogenated Jatropha biodiesel with diesel fuel in volume ratio of 30:70 (B30 on combustion characteristics (BSFC, thermal efficiency and smoke emission of single cylinder diesel engine. In this experiment, engine speed was kept constant at 1,500, 2,500, and 3,500 rpm with maximum engine load at BMEP 5 bar and injection timings were varied. Experimental result showed that at engine speed 1,500 rpm, BSFC of B30 hydrogenated and unhydrogenated Jatropha biodiesel were higher than it of diesel fuel at all injection timings (10° to 18° BTDC. At the same condition, partial hydrogenated Jatropha biodiesel showed higher BSFC than unhydrogenated Jatropha biodiesel. However, the difference in BSFC became smaller for all fuels at engine speed 2,500 rpm and 3,500 rpm at all injection timing. Jatropha biodiesel with and without partial hydrogenation tend to have higher thermal efficiency compared with diesel fuel at all engine speed and injection timing. The best injection timings to operate B30 Jatropha biodiesel with and without hydrogenation were 14°, 18° and 24° BTDC at engine speed 1,500, 2,500, and 3,500 rpm respectively. This conclusion was deduced based on the minimum value of BSFC and the maximum value of thermal efficiency. Smoke emissions for all fuels were in the same level for all conditions.

  15. The Influence of Hydrogen on the Evolving Microstructure During Fatigue Crack Growth in Metastable and Stable Austenitic Stainless Steels

    Science.gov (United States)

    Nygren, Kelly Elizabeth

    The effect of high levels of internal hydrogen on the microstructure evolving during stage II fatigue crack growth was investigated through a series of tensile and fatigue studies in metastable (304) and stable (316, 316L) stainless steels. The first, a tensile study in 304 stainless steel, identified the underlying microstructure which resulted in the flat and quasi-cleavage features on the fracture surface of a hydrogen-charged tensile bar. The second study utilized single-edge notched tensile specimens loaded in fatigue, and compared the evolving microstructure ahead of a fatigue crack for cases of an uncharged, 10 wppm hydrogen-charged, and 104 wppm hydrogen-charged 304 and 316L alloy. The final fatigue study, a small fatigue crack growth study in round bars of 304 and 316, provided a contextual comparison of microstructures to previous results in literature. In the metastable 304 stainless steel, hydrogen is found to change the nature of the martensitic transformation and subsequent fracture path. This transformation is attributed to enhanced plasticity and hydrogen-dislocation interactions stabilizing the austenitic matrix and confining slip to particular close-packed planes. The martensite acts as a fast diffusion pathway for hydrogen, leading to final fracture along martensitic laths or cleavage planes. In 316L, the material deforms via slip and twinning and hydrogen does not induce a change in deformation mechanisms. Instead, the enhanced plasticity and hydrogen-dislocation interactions increase the degree of plasticity, leading to smaller dislocation cell sizes with thicker walls before the onset of twinning. The crack interacts with a heavily twinned structure superimposed on dislocation cells, resulting in a curvature of one twin-variant in the direction of crack growth and the formation of a refined region at the fracture surface. These structures are localized to the crack surface and limited in rotation in the presence of hydrogen. The presence of a

  16. Influence of Hydrogen and Number of Particle Variants on Ordinary and Two-Way Shape Memory Effects in Ti-Ni Single Crystals

    Science.gov (United States)

    Kireeva, I. V.; Platonova, Yu. N.; Chumlyakov, Yu. I.

    2017-02-01

    The ordinary and two-way shape memory effects (SMEs) are investigated for [ overline{1} 12] single crystals of Ti-51.3Ni (at.%) alloy aged at 823 K for 1.5 h in free state and under tensile stress of 150 MPa without hydrogen and after saturation by hydrogen. It is established that without hydrogen in [ overline{1} 12] single crystals with one and four variants of Ti3Ni4 particles the maximum magnitude of the ordinary SME is 1.9-2.6% under the external stress σext = 250 MPa. Under σext > 250 MPa, crystals are destroyed. The magnitude of the two-way SME caused by the B2- R- B19' MT equal to 1.1% at σext = 0 is observed in [ overline{1} 12] single crystals with one variant of Ti3Ni4 particles. The physical reason for the observed two-way SME is the internal compressive stresses oriented along the [ overline{1} 12] directions arising from one variant of Ti3Ni4 particles as a result of aging under tensile stress of 150 MPa. It is established that hydrogen does not influence the TR temperature, reduces the plasticity, and suppresses the two-way SME. The suppression of two-way SME in the [ overline{1} 12] single crystals of the Ti-51.3Ni (at.%) alloy with one variant of Ti3Ni4 particles is caused by shielding of stress fields from one variant of Ti3Ni4 particles and multiple nucleation of R- and B19' martensite variants under loading with saturation by hydrogen.

  17. An insight into the influence of hydrogen bond acceptors on cellulose/1-allyl-3-methyl imidazolium chloride solution.

    Science.gov (United States)

    Jiang, Jiahao; Xiao, Yafei; Huang, Wenjuan; Gong, Peixin; Peng, Shuhua; He, Jianping; Fan, Minmin; Wang, Ke

    2017-12-15

    Although ionic liquids have been well established as effective solvents for the dissolution and processing of natural cellulose fibers, the detailed dissolution mechanism at the molecular level still remains unclear. Herein, the turbidimetric measurement showed that the solubility of cellulose in 1-allyl-3-methyl imidazolium chloride (AmimCl) decreased with increasing temperature. The temperature dependence of the OH stretching vibration band of cellulose in AmimCl was investigated by infrared spectroscopy. The interaction between AmimCl and different hydrogen bond acceptors were investigated by turbidimetry and NMR spectroscopy, which indicated that the excellent compatibility of the hydrogen bond acceptors with AmimCl provides more interaction sites for the hydroxyl groups of the cellulose. In addition, ionic liquids with a similar anionic structure of hydrogen bond acceptors have been synthesized. This study provides a green and safe guide for the preparation of ionic liquids with excellent solubility of cellulose. Copyright © 2017. Published by Elsevier Ltd.

  18. Pt nanoparticles modified by rare earth oxides: Electronic effect and influence to catalytic hydrogenation of 3-phenoxybenzaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Zhigang; Han, Ming; Li, Gang; Du, Yukou [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Yang, Ping, E-mail: pyang@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Zhang, Hailu [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Deng, Zongwu, E-mail: zwdeng2007@sinano.ac.cn [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2013-11-15

    Graphical abstract: - Highlights: • The rare earths modified Pt/Al{sub 2}O{sub 3} were prepared by colloidal deposition method. • Modification of Pt by the rare earth enhanced catalytic hydrogenation activity. • The activity improvement is due to electron interaction between Pt and rare earth. • The hydrogenation mechanism of rare earth modified Pt catalyst was proposed. - Abstract: The rare earth elements (La, Ce, Nd, Sm, Pr, and Gd) modified Pt/Al{sub 2}O{sub 3} catalysts were prepared by the colloidal deposition and chemical reduction methods, respectively. Pt nanoparticles with average size 3 ± 0.5 nm were uniformly dispersed on the surface of Al{sub 2}O{sub 3} for the samples prepared by the colloidal deposition method, which exhibited higher activities in the hydrogenation of 3-phenoxybenzadehyde than the corresponding samples prepared by chemical reduction method. Moreover, except Gd, the catalysts modified by rare earth elements showed better catalytic performance than unmodified Pt/Al{sub 2}O{sub 3}. For Pt–Ce/Al{sub 2}O{sub 3} catalyst, when the weight percent of Pt and Ce was 0.5 and 0.25, respectively, the hydrogenation conversion of 3-phenoxybenzaldehyde was 97.3% after 6 h reaction. This activity improvement is due to the electronic interaction between Pt and rare earth elements, which was investigated by X-ray photoelectron spectroscopy.

  19. The influence of large-amplitude librational motion on the hydrogen bond energy for alcohol–water complexes

    DEFF Research Database (Denmark)

    Andersen, Jonas; Heimdal, J.; Larsen, René Wugt

    2015-01-01

    The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with methanol and t-butanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic substitution of individual subunits enabled by a dual inlet deposition procedure provides for the first time...

  20. Copolymerization of Ethylene and Propylene Using 4th Generation Ziegler- Natta Catalyst: Influence of Cocatalyst, External Electron Donor and Hydrogen

    Directory of Open Access Journals (Sweden)

    R. Mehtarani

    2007-08-01

    Full Text Available Copolymerization of ethylene and propylene was investigated using a 4th generation phthalate Ziegler-Natta catalyst in normal hexane in a Buchi reactor. The effects of different mole fractions of [Al]/[Ti], [Si]/[Al] and various amounts of hydrogen on productivity and weight percent of ethylene on the product, were studied. In the copolymerization reactions, tri-isobutyl aluminum (TiBAl was used as cocatalyst instead of triethyl aluminum (TEAl because TiBAl produced a more amorphous copolymer. In molar ratio [TiBAl]/[Ti] = 480 the catalyst activity was at maximum and ethylene content in this ratio was at minimum. Cyclohexyl-methyldimethoxy silane was used as external donor. In molar ratio [Si]/[TiBAl] = 0.05, the copolymer showed more amorphous behavior. In this molar ratio, the external donor decreased the productivity of the catalyst and a further increase of external donor concentration increased the productivity. Hydrogen increased the productivity of the catalyst and decreased the ethylene content of the copolymer in low concentration. In high concentration, however, hydrogen decreased the productivity and increased the ethylene content of the copolymer. Hydrogen as a chain transfer agent decreased the viscosity average molecular weight.

  1. Hydrogen transfer on USY zeolites during gas oil cracking: Influence of the adsorption characteristics of the zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Corma, A.; Faraldos, M.; Martinez, A.; Mifsud, A. (CSIC, Madrid (Spain))

    1990-04-01

    In this work, the hydrogen transfer activity of two series of HY zeolites dealuminated by steam and by SiCl{sub 4} (24.47-24.24 {angstrom} unit cell) has been measured from the butene/butane ratio in the products obtained during the cracking of a vacuum gas oil at 756 K. With the steam-dealuminated zeolites, a sharp decrease in the ratio of hydrogen transfer to cracking is observed when the number of Al atoms per unit cell falls below 10. On the other hand, in samples dealuminated by SiCl{sub 4}, this ratio changes very little with dealumination. These results cannot be explained assuming the need for adjacent acid sites for the hydrogen transfer. The authors have found, by adsorption measurements of n-butane and 1-butene, that the changes in the relative rates of bimolecular (hydrogen transfer) to monomolecular (cracking) reactions, observed with dealuminated HY zeolites, can be explained by the changes in the adsorption capacity and adsorption selectivity which occur on zeolites dealuminated at different levels by different dealumination procedures, and which are due to changes in the electric fields inside the pores.

  2. Influence of the organic film thickness on the second order distributed feedback resonator properties of an organic semiconductor laser

    Science.gov (United States)

    Bencheikh, F.; Sandanayaka, A. S. D.; Matsushima, T.; Ribierre, J. C.; Adachi, C.

    2017-06-01

    We report on the cavity numerical characterization of a second order one-dimensional distributed feedback organic laser. The gain medium containing 6 wt. % of 4,4'-bis[(N-carbazole)styryl]biphenyl) in a 4,4'-bis[9-dicarbazolyl]-2,2'-biphenyl) host is vacuum deposited to form an organic thin film on a SiO2 grating. The influence of the organic film thickness on the properties of the resonant cavity is investigated through numerical calculations of both the confinement factor Γ and the Q-factor. The Q-factor is obtained using two methods, one by calculating the eigenmodes of the resonant cavity and the other by calculating the reflection spectrum. It was found that while the Γ increases with the organic film thickness, the Q-factor shows a non-monotonic function with a maximum value for a thickness of 200 nm.

  3. Binary Logistic Regression Modeling of Idle CO Emissions in Order to Estimate Predictors Influences in Old Vehicle Park

    Directory of Open Access Journals (Sweden)

    Branimir Milosavljević

    2015-01-01

    Full Text Available This paper determines, by experiments, the CO emissions at idle running with 1,785 vehicles powered by spark ignition engine, in order to verify the correctness of emissions values with a representative sample of vehicles in Serbia. The permissible emissions limits were considered for three (3 fitted binary logistic regression (BLR models, and the key reason for such analysis is finding the predictors that can have a crucial influence on the accuracy of the estimation whether such vehicles have correct emissions or not. Having summarized the research results, we found out that vehicles produced in Serbia (hereinafter referred to as “domestic vehicles” cause more pollution than imported cars (hereinafter referred to as “foreign vehicles”, although domestic vehicles are of lower average age and mileage. Another trend was observed: low-power vehicles and vehicles produced before 1992 are potentially more serious polluters.

  4. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  5. Does Birth Order and Academic Proficiency Influence Perfectionistic Self-presentation Among Undergraduate Engineering Students? A Descriptive Analysis.

    Science.gov (United States)

    Louis, Preeti Tabitha; Kumar, Navin

    2016-01-01

    Perfectionism is a multifaceted concept. It had both advantages and disadvantages. Perfectionistic traits have been associated with leadership and very intellectual people. The present study is an attempt to understand if engineering students possess perfectionistic orientation and whether it influences self-efficacy, social connectedness, and achievement motivation. The present study adopts a random sampling design to evaluate the presence of perfectionism as a personality trait among undergraduate engineering students (N = 320). Standardized inventories such as Almost Perfect Scale-Revised were administered first to identify perfectionists and second to differentiate the adaptive from the maladaptive perfectionists. Scheduled interviews were conducted with students to obtain information regarding birth order and family functioning. Findings from the study reveal that there were a significant number of maladaptive perfectionists and that they experienced higher levels of personal and societal demands leading to a negative emotional well-being in comparison to the adaptive perfectionists. We also observed that first-born children were more likely to display a perfectionistic self-presentation and from scheduled interviews, we understood that paternal influences were stronger when it came to decision-making and display of conscientiousness. The study draws on important implications for helping students to understand perfectionism and to respond to demands of the family and societal subsystems in a positive and an adaptive manner.

  6. Influence of the formation- and passivation rate of boron-oxygen defects for mitigating carrier-induced degradation in silicon within a hydrogen-based model

    Energy Technology Data Exchange (ETDEWEB)

    Hallam, Brett, E-mail: brett.hallam@unsw.edu.au; Abbott, Malcolm; Nampalli, Nitin; Hamer, Phill; Wenham, Stuart [School of Photovoltaics and Renewable Energy Engineering, Level 1 Tyree Energy Technologies Building, University of New South Wales, Kensington, NSW 2052 (Australia)

    2016-02-14

    A three-state model is used to explore the influence of defect formation- and passivation rates of carrier-induced degradation related to boron-oxygen complexes in boron-doped p-type silicon solar cells within a hydrogen-based model. The model highlights that the inability to effectively mitigate carrier-induced degradation at elevated temperatures in previous studies is due to the limited availability of defects for hydrogen passivation, rather than being limited by the defect passivation rate. An acceleration of the defect formation rate is also observed to increase both the effectiveness and speed of carrier-induced degradation mitigation, whereas increases in the passivation rate do not lead to a substantial acceleration of the hydrogen passivation process. For high-throughput mitigation of such carrier-induced degradation on finished solar cell devices, two key factors were found to be required, high-injection conditions (such as by using high intensity illumination) to enable an acceleration of defect formation whilst simultaneously enabling a rapid passivation of the formed defects, and a high temperature to accelerate both defect formation and defect passivation whilst still ensuring an effective mitigation of carrier-induced degradation.

  7. Sixth-grade students' reasoning on the order relation of integers as influenced by prior experience: an inferentialist analysis

    Science.gov (United States)

    Schindler, Maike; Hußmann, Stephan; Nilsson, Per; Bakker, Arthur

    2017-03-01

    Negative numbers are among the first formalizations students encounter in their mathematics learning that clearly differ from out-of-school experiences. What has not sufficiently been addressed in previous research is the question of how students draw on their prior experiences when reasoning on negative numbers and how they infer from these experiences. This article presents results from an empirical study investigating sixth-grade students' reasoning and inferring from school-based and out-of-school experiences. In particular, it addresses the order relation, which deals with students' very first encounters with negative numbers. Here, students can reason in different ways, depending on the experiences they draw on. We study how students reason before a lesson series and how their reasoning is influenced through this lesson series where the number line and the context debts-and-assets are predominant. For grasping the reasoning's inferential and social nature and conducting in-depth analyses of two students' reasoning, we use an epistemological framework that is based on the philosophical theory of inferentialism. The results illustrate how the students infer their reasoning from out-of-school and from school-based experiences both before and after the lesson series. They reveal interesting phenomena not previously analyzed in the research on the order relation for integers.

  8. A local energy market for electricity and hydrogen

    DEFF Research Database (Denmark)

    Xiao, Yunpeng; Wang, Xifan; Pinson, Pierre

    2017-01-01

    ), loads, hydrogen vehicles (HVs), and a hydrogen storage system (HSS) operated by a HSS agent (HSSA). An iterative LEM clearing method is proposed based on the merit order principle. Players submit offers/bids with consideration of their own preferences and profiles according to the utility functions......The proliferation of distributed energy resources entails efficient market mechanisms in distribution-level networks. This paper establishes a local energy market (LEM) framework in which electricity and hydrogen are traded. Players in the LEM consist of renewable distributed generators (DGs....... Sensitivity analysis is then implemented to discuss the influences on the LEM clearing results of capacities of DGs, Loads, and the HSS, as well as price of hydrogen from the hydrogen station (HS)....

  9. Hydrogen bonding versus van der Waals interactions: competitive influence of noncovalent interactions on 2D self-assembly at the liquid-solid interface.

    Science.gov (United States)

    Mali, Kunal S; Lava, Kathleen; Binnemans, Koen; De Feyter, Steven

    2010-12-27

    The structures of the self-assembled monolayers of various 4-alkoxybenzoic acids physisorbed at the liquid-solid interface were established by employing scanning tunnelling microscopy (STM). This study has been essentially undertaken to explore the competitive influence of van der Waals and hydrogen-bonding interactions on the process of two-dimensional self-assembly. These acid derivatives form hydrogen-bonded dimers as expected; however, the dimers organise themselves in the form of relatively complex lamellae. The characteristic feature of these lamellae is the presence of regular discommensurations or kinks along the lamella propagation direction. The formation of kinked lamellae is discussed in light of the registry mechanism of the alkyl chains with the underlying graphite substrate. The location of the kinks along a lamella depends on the number (odd or even) of carbon atoms in the alkyl chain. This result indicates that concerted van der Waals interactions of the alkyl chain units introduce the odd/even chain-length effect on the surface-assembled supramolecular patterns. The odd/even effects are retained even upon complexation with a hydrogen-bond acceptor. However, as the solvent is changed from 1-phenyloctane to 1-octanoic acid, the kinked lamellae as well as the odd/even effects disappear. This solvent-induced convergence of supramolecular patterns is attained by means of co-crystallisation of octanoic acid molecules in the 2D crystal lattice, which is evident from high-resolution STM images. The solvent co-adsorption phenomenon is discussed in terms of competing van der Waals and hydrogen-bonding interactions.

  10. Influence of in-office whitening gel pH on hydrogen peroxide diffusion through enamel and color changes in bovine teeth.

    Science.gov (United States)

    Pignoly, Christian; Camps, Lila; Susini, Guy; About, Imad; Camps, Jean

    2012-04-01

    To assess the influence of in-office whitening gel pH on whitening efficiency. Hydrogen peroxide diffusion and color changes on bovine teeth were assessed. Three gels with close hydrogen peroxide concentrations but with various pH levels were tested: Zoom 2 (Discus Dental), Opalescence Endo and Opalescence Boost (Ultradent). The pH levels were respectively: 3.0, 5.0 and 7.0. Thirty enamel slices and tooth crowns were used for both studies (n = 10 per group per study). Hydrogen peroxide diffusion through the enamel slices and the tooth crowns was spectrophotometrically recorded every 10 minutes for 1 hour to calculate the diffusion coefficients. Color changes were spectrophotometrically recorded every 10 minutes for 1 hour and quantified in term of CIE-Lab. The hydrogen peroxide diffusion coefficient through enamel ranged from 5.12 +/- 0.82 x 10(-9) cm2 s(-1) for pH 3 to 5.19 +/- 0.92 x 10(-9) cm2 S(-1) for pH 7. Through tooth crowns it ranged from 4.80 +/- 1.75 x 10(-10) cm2 s(-1) for pH 5 to 4.85 +/- 1.82 x 10(-10) cm2 s(-1) for pH 3. After 1 hour, the deltaE varied from 5.6 +/- 4.0 for pH 7 to 7.0 +/- 5.0 for pH 3 on enamel slices and from 3.9 +/- 2.5 for pH 5 to 4.9 +/- 3.5 for pH 7 on tooth crowns. There was no statistically significant difference between groups for both parameters.

  11. Hydrogen bond dynamics at the water/hydrocarbon interface.

    Science.gov (United States)

    Chowdhary, Janamejaya; Ladanyi, Branka M

    2009-04-02

    The dynamics of hydrogen bond formation and breakage for water in the vicinity of water/hydrocarbon liquid interfaces is studied using molecular dynamics simulations. Several liquid alkanes are considered as the hydrocarbon phase in order to determine the effects of their chain length and extent of branching on the properties of the adjacent water phase. In addition to defining the interface location in terms of the laboratory-frame density profiles, the effects of interfacial fluctuations are considered by locating the interface in terms of the proximity of the molecules of the other phase. We find that the hydrogen bond dynamics of interfacial water is weakly influenced by the identity of the hydrocarbon phase and by capillary waves. In addition to calculating hydrogen bond time correlations, we examine how the hydrogen bond dynamics depend on local coordination and determine the extent of cooperativity in the population relaxation of the hydrogen bonds that a given molecule participates in. The contributions of translational diffusion and reorientation of molecular O-H bonds to the mechanism of hydrogen bond breakage and reformation are investigated. In previous work, we have shown that rotation of the principal axes of water is anisotropic at the interface and depends on the initial orientation of the molecule relative to the interface. Here, we extend this analysis to the reorientation of the O-H vector and to hydrogen bond time correlation. We find that hydrogen bond dynamics are also sensitive to the initial orientation of the molecules participating in the hydrogen bond.

  12. Influences of defects evolvement on the properties of sputtering deposited ZnO:Al films upon hydrogen annealing

    Directory of Open Access Journals (Sweden)

    Shiliu Yin

    2016-06-01

    Full Text Available Understanding how the defects interact with each other and affect the properties of ZnO:Al films is very important for improving their performance as a transparent conductive oxide (TCO. In the present work, we studied the effects of hydrogen annealing on the structural, optical and electrical properties of ZnO:Al films prepared by magnetron sputtering. High resolution transmission electron microscopy observations reveal that annealing at ∼300 oC induces the formation of partial dislocations (PD and stacking faults (SF, which disrupt the lattice periodicity leading to decreased grain size. Annealing at temperatures above ∼500 oC can remove the PD and SF, but large number of zinc vacancies will be generated. Our results show that when films are annealed at ∼500 oC, the oxygen-related defects (interstitials Oi, etc. in the as-grown films can be remarkably removed or converted, which lead to increments in the carrier concentration, mobility, and the transmittance in the visible range. At annealing temperatures above 550 oC, the hydrogen etching effect becomes predominant, and Al donors are deactivated by zinc vacancies. We also find an abnormal endothermic process by thermal analysis and an abnormal increase in the resistivity during heating the sample under hydrogen atmosphere, based on which the interaction of Oi with the defects (mainly Al donors and PD is discussed. It is also demonstrated that by annealing the as-grown AZO films at ∼500 oC under hydrogen atmosphere, high performance TCO films with a low resistivity of 4.48 × 10−4 Ωcm and high transmittance of above 90% in the visible light are obtained.

  13. Influences of defects evolvement on the properties of sputtering deposited ZnO:Al films upon hydrogen annealing

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Shiliu; Shirolkar, Mandar M.; Li, Jieni; Li, Ming; Song, Xiao; Dong, Xiaolei; Wang, Haiqian, E-mail: hqwang@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-06-15

    Understanding how the defects interact with each other and affect the properties of ZnO:Al films is very important for improving their performance as a transparent conductive oxide (TCO). In the present work, we studied the effects of hydrogen annealing on the structural, optical and electrical properties of ZnO:Al films prepared by magnetron sputtering. High resolution transmission electron microscopy observations reveal that annealing at ∼300 {sup o}C induces the formation of partial dislocations (PD) and stacking faults (SF), which disrupt the lattice periodicity leading to decreased grain size. Annealing at temperatures above ∼500 {sup o}C can remove the PD and SF, but large number of zinc vacancies will be generated. Our results show that when films are annealed at ∼500 {sup o}C, the oxygen-related defects (interstitials O{sub i}, etc.) in the as-grown films can be remarkably removed or converted, which lead to increments in the carrier concentration, mobility, and the transmittance in the visible range. At annealing temperatures above 550 {sup o}C, the hydrogen etching effect becomes predominant, and Al donors are deactivated by zinc vacancies. We also find an abnormal endothermic process by thermal analysis and an abnormal increase in the resistivity during heating the sample under hydrogen atmosphere, based on which the interaction of O{sub i} with the defects (mainly Al donors and PD) is discussed. It is also demonstrated that by annealing the as-grown AZO films at ∼500 {sup o}C under hydrogen atmosphere, high performance TCO films with a low resistivity of 4.48 × 10{sup −4} Ωcm and high transmittance of above 90% in the visible light are obtained.

  14. The influence of hydrogenation and oxygen vacancies on molybdenum oxides work function and gap states for application in organic optoelectronics.

    Science.gov (United States)

    Vasilopoulou, Maria; Douvas, Antonios M; Georgiadou, Dimitra G; Palilis, Leonidas C; Kennou, Stella; Sygellou, Labrini; Soultati, Anastasia; Kostis, Ioannis; Papadimitropoulos, Giorgos; Davazoglou, Dimitris; Argitis, Panagiotis

    2012-10-03

    Molybdenum oxide is used as a low-resistance anode interfacial layer in applications such as organic light emitting diodes and organic photovoltaics. However, little is known about the correlation between its stoichiometry and electronic properties, such as work function and occupied gap states. In addition, despite the fact that the knowledge of the exact oxide stoichiometry is of paramount importance, few studies have appeared in the literature discussing how this stoichiometry can be controlled to permit the desirable modification of the oxide's electronic structure. This work aims to investigate the beneficial role of hydrogenation (the incorporation of hydrogen within the oxide lattice) versus oxygen vacancy formation in tuning the electronic structure of molybdenum oxides while maintaining their high work function. A large improvement in the operational characteristics of both polymer light emitting devices and bulk heterojunction solar cells incorporating hydrogenated Mo oxides as hole injection/extraction layers was achieved as a result of favorable energy level alignment at the metal oxide/organic interface and enhanced charge transport through the formation of a large density of gap states near the Fermi level.

  15. Molecular Dynamics Investigation of the Influence of the Hydrogen Bond Networks in Ethanol/Water Mixtures on Dielectric Spectra.

    Science.gov (United States)

    Cardona, Javier; Sweatman, Martin B; Lue, Leo

    2018-01-04

    The dielectric response of fluids to electromagnetic radiation in the microwave region originates from processes occurring at the molecular level. Understanding these processes in more detail is relevant to many fields, such as microwave heating, fluid mixing, and separation technologies. In this work, we use molecular dynamics simulations to study the dielectric spectra of ethanol/water mixtures. We compare our predictions with experimental results at different compositions. We show how the dielectric response can be estimated to a high level of accuracy using three dielectric relaxations: a dominant and slower process at microwave frequencies and two faster processes. A deeper study of the dynamics of the hydrogen bond network formed in these systems reveals how collective processes between the individual species are the origin of the final dielectric response. Our results agree with the "wait-and-switch" mechanism, which describes the dynamics of the hydrogen bond network as the combination of two processes: the fast breakage and formation of individual hydrogen bonds and the subsequent reorganization of the entire network once this process becomes energetically favorable. Since the dielectric response is related to dipole reorientations in the system, it is directly linked to these mechanisms.

  16. The influence of cross-order terms in interface mobilities for structure-borne sound source characterization: Frame-like structures

    Science.gov (United States)

    Bonhoff, H. A.; Petersson, B. A. T.

    2009-01-01

    The applicability of interface mobilities for structure-borne sound source characterization critically depends on the admissibility of neglecting the cross-order terms. Following on from a previous study [H.A. Bonhoff, B.A.T. Petersson, Journal of Sound and Vibration 311 (2008) 473-484], the influence of the cross-order terms is investigated for frame-like structures under the assumption of a uniform force-order distribution. Considering the complex power, the cross-order terms are significant from intermediate frequencies on upwards. At lower frequencies, the cross-order terms can come into play for cases where the in-phase motion of the structure along the interface is constrained. The frequency characteristics of the influence of cross-order terms for the zero-order source descriptor and coupling function are similar to those of the complex power. For non-zero source descriptor and coupling function orders, the quality of the equal-order approximation mainly depends on the presence of low-order cross-order interface mobilities. By analyzing the symmetry of an interface system, it is possible to predict which cross-order terms are equal to zero. The equal-order approximation manages to capture the main trends and overall characteristics and offers an acceptable estimate for engineering practice.

  17. Investigating the influence of curbs on single-vehicle crash injury severity utilizing zero-inflated ordered probit models.

    Science.gov (United States)

    Jiang, Ximiao; Huang, Baoshan; Zaretzki, Russell L; Richards, Stephen; Yan, Xuedong; Zhang, Hongwei

    2013-08-01

    The severity of traffic-related injuries has been studied by many researchers in recent decades. However, previous research has seldom accounted for the effects of curbed outside shoulders on traffic-related injury severity. This study applies the zero-inflated ordered probit (ZIOP) model to evaluate the influences of curbed outside shoulders, speed limit change, as well as other traditional factors on the injury severity of single-vehicle crashes. Crash data from 2003 to 2007 in the Illinois Highway Safety Database were employed in this study. The ZIOP model assumes that injury severity comes from two distinct sources: injury propensity and injury severity when this crash falls into the injury prone category. The modeling results show that on one hand, single-vehicle crashes that occurring on roadways with curbed outside shoulders are more likely to be injury prone. On the other hand, the existence of a curb decreases the likelihood of severe injury if the crash was in the injury prone category. As a result, the marginal effect analysis implies that the presence of curbs is associated with a higher likelihood of no injury and minor injury involved crashes, but a lower likelihood of incapacitating injury and fatality involved crashes. In addition, in the presence of curbed outside shoulders, the change of speed limit adds no significant impact to the injury severity of single-vehicle crashes. Moreover, the modeling results also highlight some interesting effects caused by vehicle type, light and weather conditions, and drivers' characteristics, as well as crash type and location. Through a comprehensive evaluation of the modeling results, the authors find that the ZIOP model performs well relative to the traditional ordered probit (OP) model, and can serve as an alternative in future studies of crash injury severity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  19. Adjective-noun order as representational structure: native-language grammar influences perception of similarity and recognition memory.

    Science.gov (United States)

    Mata, André; Percy, Elise J; Sherman, Steven J

    2014-02-01

    This article describes two experiments linking native-language grammar rules with implications for perception of similarity and recognition memory. In prenominal languages (e.g., English), adjectives usually precede nouns, whereas in postnominal languages (e.g., Portuguese), nouns usually precede adjectives. We explored the influence of such rules upon similarity judgments about, and recognition of, objects with multiple category attributes (one nominal attribute and one adjectival attribute). The results supported the hypothesized primacy effect of native-language word order such that nouns generally carried more weight for Portuguese speakers than for English speakers. This pattern was observed for judgments of similarity (i.e., Portuguese speakers tended to judge objects that shared a noun-designated attribute as more similar than did English speakers), as well as for false alarms in recognition memory (i.e., Portuguese speakers tended to falsely recognize more objects if they possessed a familiar noun attribute, relative to English speakers). The implications of such linguistic effects for the cognition of similarity and memory are discussed.

  20. Hydrogen induced plastic deformation of stainless steel

    NARCIS (Netherlands)

    Gadgil, V.J.; Keim, Enrico G.; Geijselaers, Hubertus J.M.

    1998-01-01

    Hydrogen can influence the behaviour of materials significantly. The effects of hydrogen are specially pronounced in high fugacities of hydrogen which can occur at the surface of steels in contact with certain aqueous environments. In this investigation the effect of high fugacity hydrogen on the

  1. Influence of Citric Acid and Hydrogen Peroxide on Postharvest Quality of Tuberose (Polianthes tuberosa L. ‘Pearl’) Cut Flowers

    OpenAIRE

    Rahimian-Boogar Abdolrahman; Salehi Hassan; Mir Noshin

    2016-01-01

    Quality of cut flowers is an important issue at postharvest as well as an important factor contributing to marketing of and profitability from the tuberose. In this study, the effects of citric acid (CA) and hydrogen peroxide (H2O2) added to the vase water on postharvest quality of tuberose cut flowers were investigated. CA was applied in concentrations of 50, 100, 200, 400 mg·dm−3 and H2O2 in concentrations of 10, 20, 40 and 80 mg·dm−3 and distilled water as control treatment. Results showed...

  2. Influence of temperature and hydrogen content on stress-induced radial hydride precipitation in Zircaloy-4 cladding

    Energy Technology Data Exchange (ETDEWEB)

    Desquines, J., E-mail: jean.desquines@irsn.fr; Drouan, D.; Billone, M.; Puls, M.P.; March, P.; Fourgeaud, S.; Getrey, C.; Elbaz, V.; Philippe, M.

    2014-10-15

    Radial hydride precipitation in stress relieved Zircaloy-4 fuel claddings is studied using a new thermal–mechanical test. Two maximum temperatures for radial hydride precipitation heat treatment are studied, 350 and 450 °C with hydrogen contents ranging between 50 and 600 wppm. The new test provides two main results of interest: the minimum hoop stress required to precipitate radial hydrides and a maximum stress above which, all hydrides precipitate in the radial direction. Based on these two extreme stress conditions, a model is derived to determine the stress level required to obtain a given fraction of radial hydrides after high temperature thermal–mechanical heat treatment. The proposed model is validated using metallographic observation data on pressurized tubes cooled down under constant pressure. Most of the samples with reoriented hydrides are further subjected to a ductility test. Using finite element modeling, the test results are analyzed in terms of crack nucleation within radial hydrides at the outer diameter and crack growth through the thickness of the tubular samples. The combination of test results shows that samples with hydrogen contents of about 100 wppm had the lowest ductility.

  3. Calculations of hydrogen diffusivity in Zr-based alloys: Influence of alloying elements and effect of stress

    Energy Technology Data Exchange (ETDEWEB)

    Yu, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jiang, C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-01

    This report summarizes the progress on modeling hydrogen diffusivity in Zr-based alloys. The presence of hydrogen (H) can detrimentally affect the mechanical properties of many metals and alloys. To mitigate these detrimental effects requires fundamental understanding of the thermodynamics and kinetics governing H pickup and hydride formation. In this work, we focus on H diffusion in Zr-based alloys by studying the effects of alloying elements and stress, factors that have been shown to strongly affect H pickup and hydride formation in nuclear fuel claddings. A recently developed accelerated kinetic Monte Carlo method is used for the study. It is found that for the alloys considered here, H diffusivity depends weakly on composition, with negligible effect at high temperatures in the range of 600-1200 K. Therefore, the small variation in compositions of these alloys is likely not a major cause of the very different H pickup rates. In contrast, stress strongly affects H diffusivity. This effect needs to be considered for studying hydride formation and delayed hydride cracking.

  4. Influence of varying hydrogen bond strength resulting from compositional variation on the vibration spectra of proton glasses: K1-x(NH4)xH2PO4

    Science.gov (United States)

    Choudhury, Rajul Ranjan; Chitra, R.; Abraham, Geogy J.

    2014-07-01

    Single crystal neutron diffraction investigation [Choudhury and Chitra, J. Phys. Condense Matter, 25 (2013) 075902] on four mixed crystals with composition (K1-x(NH4)xH2PO4) where x=0.0, 0.29, 0.67, and 1.0 belonging to the potassium dihydrogen phosphate family of hydrogen bonded ferroelectric crystals had revealed that the compositional variation results in subtle structural differences primarily in the hydrogen bonds of these crystals. The study indicated that there is a change in hydrogen bond strengths with the change in crystal composition. Spectral investigation of the same set of four mixed crystals is undertaken with an intention to study the influence of the varying hydrogen bond strength on the vibrational properties of the crystals. Room temperature Raman spectra for all the four crystals are recorded in the range 100-4000 cm-1. This Raman investigation correlates the structural changes observed from neutron diffraction investigations to the changes in the vibration spectra of the crystals. The varying N-H-O hydrogen bond strength in the mixed crystals is found to have an observable effect on the librational frequencies of the molecular components of these crystals. The strong OHO hydrogen bonds in these crystals give rise to four spectral bands in the 1500-3000 cm-1 spectral region; this is in accordance with the theoretical prediction from the tunneling model for the very strong OHO hydrogen bonds. These OHO bonds can be described by a low barrier double well potential; the vibrational energy levels of the potential are split due to quantum tunneling effects. It is observed that the varying OHO hydrogen bond strength of these crystals results in a variation in the splitting of the vibrational energy levels of the hydrogen bond potential. It is attempted to correlate the varying OHO hydrogen bond strength with the expected variation in the freezing temperature with composition of these proton glasses.

  5. Factors influencing bank geomorphology and erosion of the Haw River, a high order river in North Carolina, since European settlement.

    Science.gov (United States)

    Macfall, Janet; Robinette, Paul; Welch, David

    2014-01-01

    The Haw River, a high order river in the southeastern United States, is characterized by severe bank erosion and geomorphic change from historical conditions of clear waters and connected floodplains. In 2014 it was named one of the 10 most threatened rivers in the United States by American Rivers. Like many developed areas, the region has a history of disturbance including extensive upland soil loss from agriculture, dams, and upstream urbanization. The primary objective of this study was to identify the mechanisms controlling channel form and erosion of the Haw River. Field measurements including bank height, bankfull height, bank angle, root depth and density, riparian land cover and slope, surface protection, river width, and bank retreat were collected at 87 sites along 43.5 km of river. A Bank Erosion Hazard Index (BEHI) was calculated for each study site. Mean bank height was 11.8 m, mean width was 84.3 m, and bank retreat for 2005/2007-2011/2013 was 2.3 m. The greatest bank heights, BEHI values, and bank retreat were adjacent to riparian areas with low slope (<2). This is in contrast to previous studies which identify high slope as a risk factor for erosion. Most of the soils in low slope riparian areas were alluvial, suggesting sediment deposition from upland row crop agriculture and/or flooding. Bank retreat was not correlated to bank heights or BEHI values. Historical dams (1.2-3 m height) were not a significant factor. Erosion of the Haw River in the study section of the river (25% of the river length) contributed 205,320 m3 of sediment and 3759 kg of P annually. Concentration of suspended solids in the river increased with discharge. In conclusion, the Haw River is an unstable system, with river bank erosion and geomodification potential influenced by riparian slope and varied flows.

  6. Factors Influencing Bank Geomorphology and Erosion of the Haw River, a High Order River in North Carolina, since European Settlement

    Science.gov (United States)

    Macfall, Janet; Robinette, Paul; Welch, David

    2014-01-01

    The Haw River, a high order river in the southeastern United States, is characterized by severe bank erosion and geomorphic change from historical conditions of clear waters and connected floodplains. In 2014 it was named one of the 10 most threatened rivers in the United States by American Rivers. Like many developed areas, the region has a history of disturbance including extensive upland soil loss from agriculture, dams, and upstream urbanization. The primary objective of this study was to identify the mechanisms controlling channel form and erosion of the Haw River. Field measurements including bank height, bankfull height, bank angle, root depth and density, riparian land cover and slope, surface protection, river width, and bank retreat were collected at 87 sites along 43.5 km of river. A Bank Erosion Hazard Index (BEHI) was calculated for each study site. Mean bank height was 11.8 m, mean width was 84.3 m, and bank retreat for 2005/2007-2011/2013 was 2.3 m. The greatest bank heights, BEHI values, and bank retreat were adjacent to riparian areas with low slope (sediment deposition from upland row crop agriculture and/or flooding. Bank retreat was not correlated to bank heights or BEHI values. Historical dams (1.2–3 m height) were not a significant factor. Erosion of the Haw River in the study section of the river (25% of the river length) contributed 205,320 m3 of sediment and 3759 kg of P annually. Concentration of suspended solids in the river increased with discharge. In conclusion, the Haw River is an unstable system, with river bank erosion and geomodification potential influenced by riparian slope and varied flows. PMID:25302956

  7. Hydrogen Generator

    Science.gov (United States)

    1983-01-01

    A unit for producing hydrogen on site is used by a New Jersey Electric Company. The hydrogen is used as a coolant for the station's large generator; on-site production eliminates the need for weekly hydrogen deliveries. High purity hydrogen is generated by water electrolysis. The electrolyte is solid plastic and the control system is electronic. The technology was originally developed for the Gemini spacecraft.

  8. Influence of the Water Phase State on the Thermodynamics of Aqueous-Phase Reforming for Hydrogen Production.

    Science.gov (United States)

    Ripken, Renée M; Meuldijk, Jan; Gardeniers, Johannes G E; Le Gac, Séverine

    2017-12-22

    Hydrogen is a promising renewable energy source that can be produced from biomass using aqueous-phase reforming (APR). Here, using data obtained from AspenPlus and the literature, we evaluated the phase state, temperature-dependent enthalpy, and Gibbs free energy for the APR of small biomass model substrates. Phase equilibrium studies reveal that, under typical APR reaction conditions, the reaction mixture is in the liquid phase. Therefore, we show for the first time that the water-gas shift reaction (WGSR), which is the second main reaction of APR, must be modeled in the liquid phase, resulting in an endothermic instead of an exothermic enthalpy of reaction. A significant implication of this finding is that, although APR has been introduced as more energy saving than conventional reforming methods, the WGSR in APR has a comparable energy demand to the WGSR in steam reforming (SR). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Influence of helium on hydrogen isotope exchange in tungsten at sequential exposures to deuterium and helium–protium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bobyr, N.P., E-mail: NPBobyr@gmail.com [NRC “Kurcharov Institute”, Ac. Kurcharov sq., 1/1, Moscow 123182 (Russian Federation); Alimov, V.Kh. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Khripunov, B.I.; Spitsyn, A.V. [NRC “Kurcharov Institute”, Ac. Kurcharov sq., 1/1, Moscow 123182 (Russian Federation); Mayer, M. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Golubeva, A.V.; Petrov, V.B. [NRC “Kurcharov Institute”, Ac. Kurcharov sq., 1/1, Moscow 123182 (Russian Federation)

    2015-08-15

    Hydrogen isotopes exchange in tungsten was investigated after sequential exposures to low energy deuterium (D) and helium–seeded protium (He–seeded H) plasmas at sample temperatures of 403 and 533 K. Deuterium depth profiles were measured by the D({sup 3}He, p){sup 4}He nuclear reaction with {sup 3}He{sup +} energies between 0.69 and 4.5 MeV allowing determination of the D concentration up to a depth of 8 μm. It was found that a significant part of the deuterium initially retained in tungsten after D plasma exposure was released during sequential exposure to a protium plasma. However, exposure of the D-plasma-exposed W samples to the He–seeded H plasma reduces the amount of released deuterium as compared to pure H plasma exposure.

  10. The influence of N-doped carbon materials on supported Pd: enhanced hydrogen storage and oxygen reduction performance.

    Science.gov (United States)

    Kong, Xiang-Kai; Chen, Qian-Wang; Lun, Zheng-Yan

    2014-02-03

    N-doped graphene has become an important support for Pd in both hydrogen storage and catalytic reactions. The molecular orbitals of carbon materials (including graphene, fullerene, and small carbon clusters) and those of the supported Pd species will hybrid much stronger as N dopants are introduced, owing to the increased electrostatic attraction at the interface. This enhances the carbon substrates' catching force for the supported Pd, preventing its leaching and aggregation in many practical applications. The better dispersion and stabilization of Pd nanoparticles, which are induced by various carbon supports with N-doping, are pleasing to us and could increase their efficiency and facilitate their recycling during various reaction processes in several fields. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Evaluation of the influence of dental bleaching with 35% hydrogen peroxide in orthodontic bracket shear bond strength

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Neiva Nunes do Rego

    2013-04-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate, in vitro, the bond strength of brackets bonded to premolars previously subjected to bleaching with a 35% hydrogen peroxide. METHODS: Twenty one healthy premolars were selected and randomly divided into three groups (n = 7. Group I (G1 included teeth that were not submitted to bleaching. The enamel surfaces of Groups II (G2 and III (G3 were submitted to a bleaching process with 35% hydrogen peroxide (Whiteness HP Maxx. On Group II (G2, after bleaching, the teeth were stored for 24 hours in distilled water at 98.6 ºF, and then, premolar metallic brackets were bonded using Transbond XT (3M resin. Group III (G3 was submitted to the same procedure seven days after bleaching. After bonding, all teeth were stored in distilled water at 98.6 ºF for 24 hours. All groups were submitted to a traction test using an EMIC DL2000 universal testing machine at a speed of 0.5 mm/min. RESULTS AND CONCLUSION: The bracket resistance to debonding was compared between the groups by the Kruskal-Wallis nonparametric test (p < 0.05 and it was verified that the bleaching agent significantly reduced bracket adhesion when bonded 24 hours after bleaching. However, seven days after bleaching, there was no significant difference on the resistance to debonding among groups G1 (19,52 kgf and G3 (18,44 kgf, meaning that it is necessary to wait longer after bleaching to bond brackets.

  12. Occurrence of hydrogen sulfide in wine and in fermentation: influence of yeast strain and supplementation of yeast available nitrogen.

    Science.gov (United States)

    Ugliano, Maurizio; Kolouchova, Radka; Henschke, Paul A

    2011-03-01

    Hydrogen sulfide (H₂S) is a powerful aroma compound largely produced by yeast during fermentation. Its occurrence in wines and other fermented beverages has been associated with off-odors described as rotten egg and/or sewage. While the formation of hydrogen sulfide (H₂S) during fermentation has been extensively studied, it is the final H₂S content of wine that is actually linked to potential off-odors. Nevertheless, factors determining final H₂S content of wine have received little attention, and it is commonly assumed that high H₂S-forming fermentations will result in high final concentrations of H₂S. However, a clear relationship has never been established. In this report, we investigated the contribution of yeast strain and nitrogen addition to H₂S formation during fermentation and its consequent occurrence the resulting wines. Five commercial Saccharomyces cerevisiae wine yeast strains were used to ferment a Chardonnay juice containing 110 mg/l of YAN (yeast assimilable nitrogen), supplemented with di-ammonium phosphate (DAP) to increase YAN concentration to moderate (260 mg/l) and high (410 mg/l) levels. In contrast to the widely reported decrease in H₂S production in response to DAP addition, a non-linear relationship was found such that moderate DAP supplementation resulted in a remarkable increase in H₂S formation by each of the five wine yeasts. H₂S content of the finished wine was affected by yeast strain, YAN, and fermentation vigor. However, we did not observe a correlation between concentration of H₂S in the finished wines and H₂S produced during fermentation, with low-forming fermentations often having relatively high final H₂S and vice versa. Management of H₂S in wine through nitrogen supplementation requires knowledge of initial YAN and yeast H₂S characteristics.

  13. Investigating the Influence of Vegetation Type on Modern Leaf Wax Hydrogen Isotopes from a High Latitude Ombrotrophic Bog to Inform Paleoclimate Interpretation

    Science.gov (United States)

    Balascio, N.; D'Andrea, W. J.; Anderson, R. S.

    2016-12-01

    Leaf wax hydrogen isotopes have been used to track changes in the isotopic composition of meteoric waters in a variety of locations. However, leaf wax compounds preserved in sedimentary environments reflect a mix of plant sources that can have a large range of molecular distributions and biosynthetic fractionation factors potentially complicating paleoclimate interpretations. Here we attempt to constrain the influence of vegetation type on leaf wax hydrogen isotope values at an ombrotrophic bog in northern Norway. We present: (i) δD values of n-alkanes from modern bog vegetation to establish the influence of vegetation type on n-alkane distributions and to provide a site-specific assessment of the biosynthetic isotopic fractionation, and (ii) δD values of n-alkanes from a sediment core spanning the last 10 ka where vegetation changes have been reconstructed based on pollen analysis. We found 14 different vegetation types growing on the bog surface that have average chain lengths from 25 to 30.5 and δD values of n-C25 to n-C33 ranging from -197‰ to -116‰. These samples also have a range of δD values among n-alkane homologues, from 1‰ to 33‰. Based on isotopic measurements of modern bog water, we calculate the average apparent fractionation of n-alkanes to be -108 ± 22‰. Sedimentary δD values of n-C25 to n-C33 over the last 10 ka range from -229 to -158‰ with distinct trends among mid- and long-chain length homologues. Changes in chain lengths and δD values, at times, correspond to vegetation shifts documented by pollen data, but also show unique trends that we interpret to represent variations in local precipitation isotopes related to past hydroclimate change.

  14. Selective and regular localization of accessible Pt nanoparticles inside the walls of an ordered silica: Application as a highly active and well-defined heterogeneous catalyst for propene and styrene hydrogenation reactions

    KAUST Repository

    Boualleg, Malika

    2011-12-01

    We describe here an original methodology related to the "build-the-bottle-around-the-ship" approach yielding a highly ordered silica matrix containing regularly distributed Pt nanoparticles (NPs) located inside the silica walls, Pt@{walls}SiO2. The starting colloidal solution of crystalline Pt nanoparticles was obtained from Pt(dba)2 (dba = dibenzylidene acetone) and 3-chloropropylsilane. The resulting nanoparticles (diameter: 2.0 ± 0.4 nm determined by HRTEM) resulted hydrophilic. The NPs present in the THF colloidal solution were incorporated inside the walls of a highly ordered 2D hexagonal mesoporous silica matrix via sol-gel process using a templating route with tetraethylorthosilicate, TEOS, as the silica source, and block copolymer (EthyleneOxide) 20(PropyleneOxide)70(EthyleneOxide)20 (Pluronic P123) as the structure-directing agent. Low-temperature calcination of the crude material at 593 K led to the final solid Pt@{walls}SiO2. Characterization by IR, HRTEM, BF-STEM and HAADF-STEM, SAXS, WAXS, XRD, XPS, H2 chemisorption, etc. of Pt@{walls}SiO2 confirmed the 2D hexagonal structuration and high mesoporosity (870 m2/g) of the material as well as the presence of stable 2-nm-sized crystalline Pt(0) NPs embedded inside the walls of the silica matrix. The material displayed no tendency to NPs sintering or leaching (Pt loading 0.3 wt.%) during its preparation. Pt@{walls}SiO2 was found to be a stable, selective and highly active hydrogenation catalyst. The catalytic performances in propene hydrogenation were tested under chemical regime conditions in a tubular flow reactor (278 K, propene/H2/He = 20/16/1.09 cm3/min, P tot = 1 bar) and were found superior to those of an homologous solid containing Pt NPs along its pore channels Pt@{pores}SiO2 and to those of a classical industrial catalysts Pt/Al2O3, (TOF = 2.3 s-1 vs. TOF = 0.90 and 0.92 s-1, respectively, calculated per surface platinum atoms). Pt@{walls}SiO2 also catalyzes fast and selective styrene

  15. Khomeini and Sufism : Ayatollah Khomeini’s influence on the oppression against Sufi Orders in the Islamic Republic of Iran

    OpenAIRE

    Taffazoli, Parasto

    2014-01-01

    Since the 1979 Islamic revolution in Iran many Shia Sufi Orders, who are religious groups that exercise the mystical and spiritual elements of Shia Islam, have been forced to exile due to oppression from the government. The largest Sufi Order, The Nematollahi Soltan Alishahi Gonabadi are still in the country, but are oppressed by the Islamic regime; From an arson attack in central Tehran in 1980; The Iranian government being blamed to have imprisoned 11 members of the Soltan Alishahi Order fo...

  16. Interfacial Hydrogen Bonds and Their Influence Mechanism on Increasing the Thermal Stability of Nano-SiO2-Modified Meta-Aramid Fibres

    National Research Council Canada - National Science Library

    Chao Tang; Xu Li; Zhiwei Li; Jian Hao

    2017-01-01

    ... of nano-SiO2/meta-aramid fibre interfacial hydrogen bonds and the strengthening mechanism behind interfacial hydrogen bonds on the thermal stability of meta-aramid fibres using molecular dynamics...

  17. Influence of Citric Acid and Hydrogen Peroxide on Postharvest Quality of Tuberose (Polianthes tuberosa L. ‘Pearl’ Cut Flowers

    Directory of Open Access Journals (Sweden)

    Rahimian-Boogar Abdolrahman

    2016-06-01

    Full Text Available Quality of cut flowers is an important issue at postharvest as well as an important factor contributing to marketing of and profitability from the tuberose. In this study, the effects of citric acid (CA and hydrogen peroxide (H2O2 added to the vase water on postharvest quality of tuberose cut flowers were investigated. CA was applied in concentrations of 50, 100, 200, 400 mg·dm−3 and H2O2 in concentrations of 10, 20, 40 and 80 mg·dm−3 and distilled water as control treatment. Results showed that both compounds had significant positive effects on solution uptake, wilting and abscission of florets, relative water content, chlorophyll content, and vase life duration. The effects of 100 and 200 mg·dm−3 of CA and 20 and 40 mg·dm−3 of H2O2 proved to be more effective than other treatments. Both compounds increased the vase life of tuberose cut flowers and CA at concentrations 100 and 200 mg dm−3 and H2O2 at concentrations 20 and 40 mg dm−3 doubled this time up to 14-17 days.

  18. Influence of loading rate and hydrogen content on fracture toughness of Zr-2.5Nb pressure tube material

    Energy Technology Data Exchange (ETDEWEB)

    Bind, A.K. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Singh, R.N., E-mail: rnsingh@barc.gov.in [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Division of Solid Mechanics, Lund University, SE22100 (Sweden); Khandelwal, H.K. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Sunil, S.; Avinash, G.; Chakravartty, J.K. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Ståhle, P. [Division of Solid Mechanics, Lund University, SE22100 (Sweden)

    2015-10-15

    For the safety assessment of PHWR, it is required to study the flaw tolerance capacity of the pressure tubes as a function of the loading rate. In this work, the effect of loading rate and hydrogen content on the fracture behaviour of a Zr-2.5Nb alloy pressure tube was investigated between 25 and 300 °C. For the as received material, the pulling rate only had an effect on fracture toughness at 25 °C whereas for hydrided material the pulling rate affected fracture toughness in the transition regime. For all pulling rates, hydrided materials showed typical S curve behavior with an increase in lower shelf, upper shelf and transition temperature with pulling rate. The number of axial splits on fracture surfaces increased with an increase in the pulling rate and a decrease in temperature and fracture toughness was found to decrease with an increase in the number of axial splits. The reduction in fracture toughness is attributed to a localised deformation between axial splits.

  19. Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide: their influence on some phenological and biochemical behaviors

    Science.gov (United States)

    Lizárraga-Paulín, Eva-Guadalupe; Miranda-Castro, Susana-Patricia; Moreno-Martínez, Ernesto; Lara-Sagahón, Alma-Virginia; Torres-Pacheco, Irineo

    2013-01-01

    Objective: To evaluate the effect of chitosan (CH) and hydrogen peroxide (H2O2) seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology, the H2O2 presence, the catalase (CAT) activity, and the protein quantity. Methods: Seven groups of ten seeds for each maize variety were treated with CH (2% (20 g/L) and 0.2% (2 g/L)) or H2O2 (8 mmol/L) by coating, sprinkling, or both. Germination and seedling growth were measured. One month after germination, the presence of H2O2 in seedlings in the coated seed treatments was evaluated. Protein content and CAT activity were determined under all treatments. Results: H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize (QPM) variety. Seedlings had a higher emergence velocity under this treatment in both varieties. CH and H2O2 sprinklings did not have an effect on seedling phenology. Exogenous application of H2O2 promoted an increase of endogenous H2O2. CH and H2O2 seedling sprinkling increased the protein content in both maize varieties, while there was no significant effect on the CAT activity of treated seeds and seedlings. Conclusions: CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application. PMID:23365007

  20. First- and Second-Order Metacognitive Judgments of Semantic Memory Reports: The Influence of Personality Traits and Cognitive Styles

    Science.gov (United States)

    Buratti, Sandra; Allwood, Carl Martin; Kleitman, Sabina

    2013-01-01

    In learning contexts, people need to make realistic confidence judgments about their memory performance. The present study investigated whether second-order judgments of first-order confidence judgments could help people improve their confidence judgments of semantic memory information. Furthermore, we assessed whether different personality and…

  1. The influence of dispersion slope to the higher-order dispersion coefficients for highly-nonlinear fibers

    Science.gov (United States)

    Othman, N.; Shah, N. S. M.; Tay, K. G.; Pakarzadeh, H.; Cholan, N. A.; Talib, R.

    2017-09-01

    The highly-nonlinear fiber is the ideal gain medium for many applications particularly because its dispersion can be easily engineered. However, the modification of the fiber dispersion will affect the higher-order dispersion coefficients. Hence, this paper investigates the effect of highly-nonlinear dispersion-shifted fiber dispersion profile on the higher-order dispersion coefficients which are the fourth-order and sixth-order dispersion coefficients. The dispersion profile was modified by varying the slope at zero-dispersion wavelength. The fourth-order dispersion coefficient exhibits changes from positive to negative value as the slope at zero-dispersion wavelength is getting higher. Meanwhile, sixth-order dispersion coefficient remains with the positive value even though it shows the reduction as the slope is increased, however it will eventually become negative when the dispersion is high enough. In short, the values of both fourth-order and sixth-order dispersion coefficients at zero-dispersion wavelength decrease when the slope increases. At the request of all authors of the paper, an updated version of this article was published on 13 October 2017. The original version supplied to AIP Publishing had an incorrect affiliation for R. Talib. The affiliation for R. Talib was changed from 3Shiraz University of Technology to 1Universiti Tun Hussein Onn Malaysia. This has been corrected in the updated and re-published version.

  2. Influence of carbohydrates and proteins concentration on fermentative hydrogen production using canteen based waste under acidophilic microenvironment.

    Science.gov (United States)

    Reddy, M Venkateswar; Chandrasekhar, K; Mohan, S Venkata

    2011-10-10

    Functional role of biomolecules viz., carbohydrates and proteins on acidogenic biohydrogen (H(2)) production was studied through the treatment of canteen based composite food waste. The performance was evaluated in an anaerobic sequencing batch reactor (AnSBR) at pH 6 with five variable organic loading conditions (OLR1, 0.854; OLR2, 1.69; OLR3, 3.38; OLR4, 6.54 and OLR5, 9.85kgCOD/m(3)-day). Experimental data depicted the feasibility of H(2) production from the stabilization of food waste and was found to depend on the substrate load. Among the five loading conditions studied, OLR4 documented maximum H(2) production (69.95mmol), while higher substrate degradation (3.99kgCOD/m(3)-day) was observed with OLR5. Specific hydrogen yield (SHY) vary with the removal of different biomolecules and was found to decrease with increase in the OLR. Maximum SHY was observed with hexose removal at OLR1 (139.24mol/kg Hexose(R) at 24h), followed by pentoses (OLR1, 108.26mol/kg Pentose(R) at 48h), proteins (OLR1, 109.71mol/kg Protein(R) at 48h) and total carbohydrates (OLR1, 58.31mol/kg CHO(R) at 24h). Proteins present in wastewater helped to maintain the buffering capacity but also enhanced the H(2) production by supplying readily available organic nitrogen to the consortia. Along with carbohydrates and proteins, total solids also registered good removal. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. The research of cytokinin and hydrogen peroxide influence on the leaf mesophyll structure and morphometric parameters of winter wheat

    Directory of Open Access Journals (Sweden)

    Vladislav V. Zhuk

    2013-04-01

    Full Text Available The last leaf mesophyll structure of Triticum aestivumcv. ‘Tronka’which was grown in the field experiment conditions was investigated by the method of confocal laser scanning microscopy. The experiment plants were treated by BAP and Н 2О2 in booting phase. It is established that plant treatment didn’t effect on structure of leaf tissues but enhanced the functional ability of chloroplast pigment complexes. It has shown that influence of exogenous BAP enhanced chlorophyll autofluorescence, especially in palisade mesophyll cells, delayed aging of pigment complex. The action of exogenous mainly increased chlorophyll fluorescence of spongy mesophyll near stomata, but its influence was less significant than BAP. In winter wheat plants treated by BAP and Н 2О2 plant height and last leaf length enlarged. The plant treatment by BAP increased productivity of T. aestivumcv. ‘Tronka’ mainly by the cost of increasing of corns’ quantity in ear and corns’weight.

  4. Offshore Facilities to Produce Hydrogen

    Directory of Open Access Journals (Sweden)

    Pilar Blanco-Fernández

    2017-06-01

    Full Text Available As a result of international agreements on the reduction of CO2 emissions, new technologies using hydrogen are being developed. Hydrogen, despite being the most abundant element in Nature, cannot be found in its pure state. Water is one of the most abundant sources of hydrogen on the planet. The proposal here is to use energy from the sea in order to obtain hydrogen from water. If plants to obtain hydrogen were to be placed in the ocean, the impact of long submarines piping to the coast will be reduced. Further, this will open the way for the development of ships propelled by hydrogen. This paper discusses the feasibility of an offshore installation to obtain hydrogen from the sea, using ocean wave energy.

  5. Minimal Influence of [NiFe] Hydrogenase on Hydrogen Isotope Fractionation in H2-Oxidizing Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    Brian J. Campbell

    2017-10-01

    Full Text Available Fatty acids produced by H2-metabolizing bacteria are sometimes observed to be more D-depleted than those of photoautotrophic organisms, a trait that has been suggested as diagnostic for chemoautotrophic bacteria. The biochemical reasons for such a depletion are not known, but are often assumed to involve the strong D-depletion of H2. Here, we cultivated the bacterium Cupriavidus necator H16 (formerly Ralstonia eutropha H16 under aerobic, H2-consuming, chemoautotrophic conditions and measured the isotopic compositions of its fatty acids. In parallel with the wild type, two mutants of this strain, each lacking one of two key hydrogenase enzymes, were also grown and measured. In all three strains, fractionations between fatty acids and water ranged from -173‰ to -235‰, and averaged -217‰, -196‰, and -226‰, respectively, for the wild type, SH- mutant, and MBH- mutant. There was a modest increase in δD as a result of loss of the soluble hydrogenase enzyme. Fractionation curves for all three strains were constructed by growing parallel cultures in waters with δDwater values of approximately -25‰, 520‰, and 1100‰. These curves indicate that at least 90% of the hydrogen in fatty acids is derived from water, not H2. Published details of the biochemistry of the soluble and membrane-bound hydrogenases confirm that these enzymes transfer electrons rather than intact hydride (H- ions, providing no direct mechanism to connect the isotopic composition of H2 to that of lipids. Multiple lines of evidence thus agree that in this organism, and presumably others like it, environmental H2 plays little or no direct role in controlling lipid δD values. The observed fractionations must instead result from isotope effects in the reduction of NAD(PH by reductases with flavin prosthetic groups, which transfer two electrons and acquire H+ (or D+ from solution. Parallels to NADPH reduction in photosynthesis may explain why D/H fractionations in C. necator

  6. Influence of high-order mechanics on simulation of glacier response to climate change: insights from Haig Glacier, Canadian Rocky Mountains

    Directory of Open Access Journals (Sweden)

    S. Adhikari

    2013-09-01

    Full Text Available Evolution of glaciers in response to climate change has mostly been simulated using simplified dynamical models. Because these models do not account for the influence of high-order physics, corresponding results may exhibit some biases. For Haig Glacier in the Canadian Rocky Mountains, we test this hypothesis by comparing simulation results obtained from 3-D numerical models that deal with different assumptions concerning physics, ranging from simple shear deformation to comprehensive Stokes flow. In glacier retreat scenarios, we find a minimal role of high-order mechanics in glacier evolution, as geometric effects at our site (the presence of an overdeepened bed result in limited horizontal movement of ice (flow speed on the order of a few meters per year. Consequently, high-order and reduced models all predict that Haig Glacier ceases to exist by ca. 2080 under ongoing climate warming. The influence of high-order mechanics is evident, however, in glacier advance scenarios, where ice speeds are greater and ice dynamical effects become more important. Although similar studies on other glaciers are essential to generalize such findings, we advise that high-order mechanics are important and therefore should be considered while modeling the evolution of active glaciers. Reduced model predictions may be adequate for other glaciologic and topographic settings, particularly where flow speeds are low and where mass balance changes dominate over ice dynamics in determining glacier geometry.

  7. Point-of-Purchase Calorie Labeling Has Little Influence on Calories Ordered Regardless of Body Mass Index.

    Science.gov (United States)

    Rendell, Sarah Litman; Swencionis, Charles

    2014-09-01

    The obesity epidemic has incited legislation aimed to inform consumers of the nutritional value of food items available in restaurants and fast food establishments, with the presumption that knowing the caloric content in a meal might enable patrons to make healthier choices when ordering. However, available research shows mixed results regarding consumers' use of calorie information to promote healthier purchases. The aim of this study was to determine whether menu type, specifically having viewed a menu with calorie disclosures or not, would have an impact on how many calories were in a lunch meal ordered by a patron. Additionally, we sought to identify body mass index (BMI) as a moderator of the relationship between viewing a menu with or without calorie information and the number of calories an individual orders for lunch. Two hundred forty-five adults participated in the study and completed the questionnaire. Results indicated neither menu type, nor reporting having seen calorie information, was significantly related to the number of calories in the foods that participants ordered, even after controlling demographic variables age, sex, income, education, race/ethnicity, and BMI. BMI did not serve as a moderator in the relationship between menu type and food calories ordered. Implications for policy change and clinical work with overweight and obese patients are discussed.

  8. The geopolitics in the spheres of influence, domination, and overrule: towards a new world order or disorder?

    OpenAIRE

    Mulaj, Isa

    2012-01-01

    The term New World Order (NWO) appears to get a more comprehensive meaning from the most recent evolution of dramatic events in various parts of the world. Officially, there is still no any unified approach how it may look like, upon which pillars it will be built, and how it would operate. More assumptions can be heard by ordinary people than by those who are believed to have considerable impact on the flows of this outspoken order. Unlike great revolutionary changes of the past, e.g. the be...

  9. [Determination of deuterium concentration in foods and influence of water with modified isotopic composition on oxidation parameters and heavy hydrogen isotopes content in experimental animals].

    Science.gov (United States)

    Basov, A A; Bykov, I M; Baryshev, M G; Dzhimak, S S; Bykov, M I

    2014-01-01

    The article presents the results of the study of the deuterium (D) content in food products as well as the influence of deuterium depleted water (DDW) on the concentration of heavy hydrogen isotopes in the blood and lyophilized tissues of rats. The most significant difference in the content of D was found between potato and pork fat, which indexes the standard delta notation (δ) D in promille, related to the international standard SMOW (Standard Mean Ocean of Water) amounted to -83,2 per thousand and -250,7 per thousand, respectively (pdeuterium concentration ranged from -75,5 per thousand (Narzan) to +72,1 per thousand (Kubai), that indicates the ability of some food products to increase the concentration of heavy hydrogen atoms in the body. The data obtained in the experimental modeling of the diet of male Wistar rats in the age of 5-6 mo (weight 235 ± 16 g) using DDW (δD = -743,2 per thousand) instead of drinking water (δD = -37,0 per thousand) with identical mineral composition showed that after 2 weeks significant (p deuterium-protium, D/H) gradient in the body is possible. Changing the direction of isotopic D/H gradient in laboratory animals in comparison with its physiological indicators (72-127 per thousand, "plasma>tissue") is due to different rates ofisotopic exchange reactions in plasma and tissues (liver, kidney, heart), which can be explained by entering into the composition of a modified diet of organic substrates with more than DDW concentration D, which are involved in the construction of cellular structures and eventually lead to a redistribution of D and change direction of D/H gradient "plasma

  10. Hydrogen Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-01

    The Hydrogen Bibliography is a compilation of research reports that are the result of research funded over the last fifteen years. In addition, other documents have been added. All cited reports are contained in the National Renewable Energy Laboratory (NREL) Hydrogen Program Library.

  11. Influence of second-order random wave kinematics on the design loads of offshore wind turbine support structures

    DEFF Research Database (Denmark)

    Natarajan, Anand

    2014-01-01

    The impact of wave model nonlinearities on the design loads of wind turbine monopile foundations is delineated based on a second-order nonlinear randomwave model that satisfies the boundary conditions at the free surface and by including the effects of convective acceleration in the inertial load...

  12. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  13. Influence of demetallization of hydrogenated sunflower oil on changes in the forms of heavy metals and their pro-oxidative effects.

    Science.gov (United States)

    Ianov, K; Maneva, D; Ivanov, S

    1992-11-01

    The effect of removing heavy metals from hydrogenated sunflower oil using a method based on changes in the contents of the various forms of the heavy metals copper, iron, zinc and nickel and their respective pro-oxidative effects was studied. A high degree of removal of dissociated and bounded ions was observed for hydrogenated oil, while there was no change in the contents of the co-ordination form. The pro-oxidative effect of the dissociated ions and of the bound metal ions in hydrogenated oil decreased nine-fold and seven-fold, respectively, compared with that of the non-hydrogenated oil, as a result of which the oxidation stability of hydrogenated oil increased two-fold. Comparative studies confirmed as appropriate the use of wash waters and auxiliary solutions that do not contain heavy metals for the processing of the hydrogenate after the classical technology.

  14. Hydrogen in Martian Meteorites

    Science.gov (United States)

    Peslier, A. H.; Hervig, R.; Irving, T.

    2017-01-01

    Most volatile studies of Mars have targeted its surface via spacecraft and rover data, and have evidenced surficial water in polar caps and the atmosphere, in the presence of river channels, and in the detection of water bearing minerals. The other focus of Martian volatile studies has been on Martian meteorites which are all from its crust. Most of these studies are on hydrous phases like apatite, a late-stage phase, i.e. crystallizing near the end of the differentiation sequence of Martian basalts and cumulates. Moreover, calculating the water content of the magma a phosphate crystallized from is not always possible, and yet is an essential step to estimate how much water was present in a parent magma and its source. Water, however, is primarily dissolved in the interiors of differentiated planets as hydrogen in lattice defects of nominally anhydrous minerals (olivine, pyroxene, feldspar) of the crust and mantle. This hydrogen has tremendous influence, even in trace quantities, on a planet's formation, geodynamics, cooling history and the origin of its volcanism and atmosphere as well as its potential for life. Studies of hydrogen in nominally anhydrous phases of Martian meteorites are rare. Measuring water contents and hydrogen isotopes in well-characterized nominally anhydrous minerals of Martian meteorites is the goal of our study. Our work aims at deciphering what influences the distribution and origin of hydrogen in Martian minerals, such as source, differentiation, degassing and shock.

  15. Influence of air contaminants on planar, self-breathing hydrogen PEM fuel cells in an outdoor environment

    Science.gov (United States)

    Biesdorf, Johannes; Zamel, Nada; Kurz, Timo

    2014-02-01

    In this study, the effects of air contaminants on the operation of air-breathing fuel cells in an outdoor environment are investigated. For this purpose, a unique testing platform, which allows continuous operation of 30 cells at different locations, was developed. Three of these testing platforms were placed at different sites in Freiburg im Breisgau, Germany, with high variances of weather and pollution patterns. These locations range from a highly polluted place next to a busy highway to a location with virtually pure air at an altitude of 1205 m. The fuel cells were tested at all sites for over 4500 h in continuous operation. The degradation of the cells due to air pollutants was measured as a voltage decrease for three different operation loads and membranes from two different manufactures. As the temperature of the fuel cells has not been regulated, the irreversible degradation of the cell voltages could not be isolated from the dominant influence of the temperature in the raw data. With the use of the measured data, the impact of real mixtures of air contaminants was observed to be mainly reversible.

  16. INFLUENCE OF THE HIGHER ORDER DERIVATIVES ON THE PLANET PERIHELION PRECESSION IN THE EINSTEIN FIELD EQUATIONS FOR VACUUM CONDITION

    Directory of Open Access Journals (Sweden)

    Teguh Budi Prayitno

    2011-04-01

    Full Text Available This paper studies the effect of higher order derivative tensor in the Einstein field equations for vacuum condition on the planet perihelion precession. This tensor was initially proposed as the space-time curvature tensor by Deser and Tekin on discussions about the energy effects caused by this tensor. However, they include this tensor to Einstein field equations as a new model in general relativity theory. This is very interesting since there are some questions in cosmology and astrophysics that have no answers. Thus, they hoped this model could solve those problems by finding analytical or perturbative solution and interpreting it. In this case, the perturbative solution was used to find the Schwarzschild solution and it was also applied to consider the planetary motion in the solar gravitational field. Furthermore, it was proven that the tensor is divergence-free in order to keep the Einstein field equations remain valid.

  17. Influence of aperiodic modulations on first-order transitions: Numerical study of the two-dimensional Potts model

    Science.gov (United States)

    Girardi, D.; Branco, N. S.

    2011-06-01

    We study the Potts model on a rectangular lattice with aperiodic modulations in its interactions along one direction. Numerical results are obtained using the Wolff algorithm and for many lattice sizes, allowing for a finite-size scaling analyses to be carried out. Three different self-dual aperiodic sequences are employed, which leads to more precise results, since the exact critical temperature is known. We analyze two models, with 6 and 15 number of states: both present first-order transitions on their uniform versions. We show that the Harris-Luck criterion, originally introduced in the study of continuous transitions, is obeyed also for first-order ones. Also, we show that the new universality class that emerges for relevant aperiodic modulations depends on the number of states of the Potts model, as obtained elsewhere for random disorder, and on the aperiodic sequence. We determine the occurrence of log-periodic behavior, as expected for models with aperiodic modulated interactions.

  18. Storing Renewable Energy in the Hydrogen Cycle.

    Science.gov (United States)

    Züttel, Andreas; Callini, Elsa; Kato, Shunsuke; Atakli, Züleyha Özlem Kocabas

    2015-01-01

    An energy economy based on renewable energy requires massive energy storage, approx. half of the annual energy consumption. Therefore, the production of a synthetic energy carrier, e.g. hydrogen, is necessary. The hydrogen cycle, i.e. production of hydrogen from water by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines is a closed cycle. Electrolysis splits water into hydrogen and oxygen and represents a mature technology in the power range up to 100 kW. However, the major technological challenge is to build electrolyzers in the power range of several MW producing high purity hydrogen with a high efficiency. After the production of hydrogen, large scale and safe hydrogen storage is required. Hydrogen is stored either as a molecule or as an atom in the case of hydrides. The maximum volumetric hydrogen density of a molecular hydrogen storage is limited to the density of liquid hydrogen. In a complex hydride the hydrogen density is limited to 20 mass% and 150 kg/m(3) which corresponds to twice the density of liquid hydrogen. Current research focuses on the investigation of new storage materials based on combinations of complex hydrides with amides and the understanding of the hydrogen sorption mechanism in order to better control the reaction for the hydrogen storage applications.

  19. Determining the Spatial Influence of Imported and Local Water Sources to Municipal Tap Water Systems in the Southwestern United States Using Stable Isotopes of Oxygen and Hydrogen

    Science.gov (United States)

    Stalker, J. C.; Kennedy, C. D.; Bowen, G. J.

    2010-12-01

    In arid and semi-arid parts of the southwestern USA, imported waters derived from large canal systems like the Colorado River Aqueduct, Los Angeles Aqueduct, and the California Aqueduct service a significant component of the regional water needs. These waters are sourced primarily from high altitude snowmelt runoff and have relatively low annually averaged stable isotope ratios of hydrogen and oxygen (δD, δ18O) (-99 to -127‰, -10 to -13‰,) when compared to water derived from local rainfall and surface river sources (-35 to -42 ‰, -5 to -7‰) in southern California, western Arizona, and southern Nevada. The distinct isotope signatures of these two waters can be used to differentiate the two sources in tap water from municipal systems. In this study, samples of tap water, aqueduct water, and surface water were collected throughout the Southwest to produce a series of maps of the spatial influence of imported water in municipal tap water. This data was then be used to develop mixing models to determine the relative importance of imported water regionally, and track the prominence of the movement of these imported waters after initial use and addition to a system. The use of isotopes to trace this anthropogenically introduced water is of interest to water management, resolving water rights issues and disputes, as well as environmental applications in ecological studies. Additionally these tracing methods may be applied worldwide in areas where the movement and dynamics of hydrologic systems are either unclear or unknown.

  20. The influence of surface oxygen and hydroxyl groups on the dehydrogenation of ethylene, acetic acid and hydrogenated vinyl acetate on pure Pd(1 0 0): A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanping [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Dong, Xiuqin [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Yu, Yingzhe, E-mail: yzhyu@tju.edu.cn [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Zhang, Minhua, E-mail: mhzhangtj@163.com [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China)

    2016-12-01

    Highlights: • All dehydrogenation reactions in vinyl acetate synthesis on Pd(1 0 0) were studied. • The energy barriers of the transition state of the three reactions were calculated. • The influence of surface Os and OHs on all dehydrogenation actions was discussed. - Abstract: On the basis of a Langmuir–Hinshelwood-type mechanism, the dehydrogenation of ethylene, acetic acid and hydrogenated vinyl acetate (VAH) on pure Pd(1 0 0) with surface oxygen atoms (Os) and hydroxyl groups (OHs) was studied with density functional theory (DFT) method. Our calculation results show that both Os and OHs can consistently reduce the activation energies of dehydrogenation of ethylene, acetic acid and VAH to some degree with only one exception that OHs somehow increase the activation energy of VAH. Based on Langmuir–Hinshelwood mechanism, the three dehydrogenation reactions in presence of surface Os and OHs are almost consistently favored, compared with the corresponding processes on clean Pd(1 0 0) surfaces, and thus a Langmuir–Hinshelwood-type mechanism may not be excluded beforehand when investigating the microscopic performance of the oxygen-assisted vinyl acetate synthesis on Pd(1 0 0) catalysts.

  1. Causal ordering of physical self-concept and exercise behavior: reciprocal effects model and the influence of physical education teachers.

    Science.gov (United States)

    Marsh, Herbert W; Papaioannou, Athanasios; Theodorakis, Yannis

    2006-05-01

    Does prior physical self-concept influence subsequent exercise behavior? On the basis of a large sample of physical education classes (2,786 students, 200 classes, 67 teachers) collected early (Time 1) and late (Time 2) in the school year, findings support a reciprocal effects model in which prior physical self-concept and exercise behavior both influence subsequent physical self-concept and exercise behavior. Whereas variables from the theory of planned behavior (TOPB; behavioral intentions, perceived behavioral control, exercise attitudes) also contributed to the prediction of subsequent exercise behavior, the effect of prior physical self-concept was significant for subsequent outcomes after controlling these variables, suggesting that the TOPB should be supplemented with self-concept measures. On the basis of multilevel models, there were systematic differences in these variables for students taught by different teachers that generalized over time and across different classes taught by the same teacher. Support for the reciprocal effects model was robust. 2006 APA, all rights reserved

  2. Co/ZnO and Ni/ZnO catalysts for hydrogen production by bioethanol steam reforming. Influence of ZnO support morphology on the catalytic properties of Co and Ni active phases

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa-Serra, J.F.; Chica, A. [Instituto de Tecnolgia Quimica (UPV-CSIC), Universidad Politecnica de Valencia, Consejo Superior de Investigaciones Cientificas, Avenida de los naranjos s/n, 46022 Valencia (Spain); Guil-Lopez, R. [Instituto de Catalisis y Petroleoquimica, CSIC, Marie Curie 2, Cantoblanco, 28049 Madrid (Spain)

    2010-07-15

    Renewable hydrogen production from steam reforming of bioethanol is an interesting approach to produce sustainable hydrogen. However, simultaneous competitive reactions can occur, decreasing the hydrogen production yield. To overcome this problem, modifications in the steam reforming catalysts are being studied. Ni and Co active phases supported over modified ZnO have been widely studied in hydrogen production from steam reforming of bioethanol. However, the influence of the morphology and particle size of ZnO supports on the catalytic behaviour of the supported Ni and Co has not been reported. In the present work, we show how the morphology, shape, and size of ZnO support particles can control the impregnation process of the metal active centres, which manages the properties of active metallic particles. It has been found that nanorod particles of ZnO, obtained by calcination of Zn acetate, favour the metal-support interactions, decreasing the metallic particle sizes and avoiding metal (Co or Ni) sinterization during the calcination of metal precursors. Small metallic particle sizes lead to high values of active metal exposure surface, increasing the bioethanol conversion and hydrogen production. (author)

  3. Interfacial Hydrogen Bonds and Their Influence Mechanism on Increasing the Thermal Stability of Nano-SiO2-Modified Meta-Aramid Fibres

    Directory of Open Access Journals (Sweden)

    Chao Tang

    2017-10-01

    Full Text Available For further analysis of the effect of nano-doping on the properties of high polymers and research into the mechanism behind modified interfacial hydrogen bonds, a study on the formation probability of nano-SiO2/meta-aramid fibre interfacial hydrogen bonds and the strengthening mechanism behind interfacial hydrogen bonds on the thermal stability of meta-aramid fibres using molecular dynamics is performed in this paper. First, the pure meta-aramid fibre and nano-SiO2/meta-aramid fibre mixed models with nanoparticle radiuses of 3, 5, 7 and 9 Å (1 Å = 10−1 nm are built, and then the optimization process and dynamics simulation of the models are conducted. The dynamics simulation results indicate that the number of hydrogen bonds increase due to the doping by nano-SiO2 and that the number of interfacial hydrogen bonds increases with the nanoparticle radius. By analysing the hydrogen bond formation probability of all the atom pairs in the mixed model with pair correlation functions (PCFs, it can be observed that the hydrogen bond formation probability between the oxygen atom and hydrogen atom on the nanoparticle surface is the greatest. An effective way to increase the number of interfacial hydrogen bonds in nano-SiO2 and meta-aramid fibres is to increase the number of hydrogen atoms on the nano-silica surface and oxygen atoms in the meta-aramid fibre. By using the radial distribution function (RDF, the conclusion can be further drawn that the hydrogen bond formation probability is at a maximum when the atomic distance is 2.7–2.8 Å; therefore, increasing the number of atoms within this range can significantly increase the formation probability of hydrogen bonds. According to the results of chain movement, the existence of interfacial hydrogen bonds effectively limits the free movement of the molecular chains of meta-aramid fibres and enhances the thermal stability of meta-aramid fibres. The existence of interfacial hydrogen bonds is one of the

  4. The hydrogen laminar jet

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Sanz, M. [Departamento de Motopropulsion y Termofluidomecanica, ETSI Aeronauticos, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Rosales, M. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain); Instituto de Innovacion en Mineria y Metalurgia, Avenida del Valle 738, Santiago (Chile); Sanchez, A.L. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain)

    2010-04-15

    Numerical and asymptotic methods are used to investigate the structure of the hydrogen jet discharging into a quiescent air atmosphere. The analysis accounts in particular for the variation of the density and transport properties with composition. The Reynolds number of the flow R{sub j}, based on the initial jet radius a, the density {rho}{sub j} and viscosity {mu}{sub j} of the jet and the characteristic jet velocity u{sub j}, is assumed to take moderately large values, so that the jet remains slender and stable, and can be correspondingly described by numerical integration of the continuity, momentum and species conservation equations written in the boundary-layer approximation. The solution for the velocity and composition in the jet development region of planar and round jets, corresponding to streamwise distances of order R{sub j}a, is computed numerically, along with the solutions that emerge both in the near field and in the far field. The small value of the hydrogen-to-air molecular weight ratio is used to simplify the solution by considering the asymptotic limit of vanishing jet density. The development provides at leading-order explicit analytical expressions for the far-field velocity and hydrogen mass fraction that describe accurately the hydrogen jet near the axis. The information provided can be useful in particular to characterize hydrogen discharge processes from holes and cracks. (author)

  5. Biomimetic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Krassen, Henning

    2009-05-15

    Hydrogenases catalyze the reduction of protons to molecular hydrogen with outstanding efficiency. An electrode surface which is covered with active hydrogenase molecules becomes a promising alternative to platinum for electrochemical hydrogen production. To immobilize the hydrogenase on the electrode, the gold surface was modified by heterobifunctional molecules. A thiol headgroup on one side allowed the binding to the gold surface and the formation of a self-assembled monolayer. The other side of the molecules provided a surface with a high affinity for the hydrogenase CrHydA1 from Chlamydomonas reinhardtii. With methylviologen as a soluble energy carrier, electrons were transferred from carboxy-terminated electrodes to CrHydA1 and conducted to the active site (H-cluster), where they reduce protons to molecular hydrogen. A combined approach of surface-enhanced infrared absorption spectroscopy, gas chromatography, and surface plasmon resonance allowed quantifying the hydrogen production on a molecular level. Hydrogen was produced with a rate of 85 mol H{sub 2} min{sup -1} mol{sup -1}. On a 1'- benzyl-4,4'-bipyridinum (BBP)-terminated surface, the electrons were mediated by the monolayer and no soluble electron carrier was necessary to achieve a comparable hydrogen production rate (approximately 50% of the former system). The hydrogen evolution potential was determined to be -335 mV for the BBP-bound hydrogenase and -290 mV for the hydrogenase which was immobilized on a carboxy-terminated mercaptopropionic acid SAM. Therefore, both systems significantly reduce the hydrogen production overpotential and allow electrochemical hydrogen production at an energy level which is close to the commercially applied platinum electrodes (hydrogen evolution potential of -270 mV). In order to couple hydrogen production and photosynthesis, photosystem I (PS1) from Synechocystis PCC 6803 and membrane-bound hydrogenase (MBH) from Ralstonia eutropha were bound to each other

  6. The influence of birth order and number of siblings on adolescent body composition: evidence from a Brazilian birth cohort study.

    Science.gov (United States)

    de Oliveira Meller, Fernanda; Assunção, M C F; Schäfer, A A; de Mola, C L; Barros, A J D; Dahly, D L; Barros, F C

    2015-07-14

    The aim of this study was to estimate the association between birth order and number of siblings with body composition in adolescents. Data are from a birth cohort study conducted in Pelotas, Brazil. At the age of 18 years, 4563 adolescents were located, of whom 4106 were interviewed (follow-up rate 81.3 %). Of these, 3974 had complete data and were thus included in our analysis. The variables used in the analysis were measured during the perinatal period, or at 11, 15 and/or 18 years of age. Body composition at 18 years was collected by air displacement plethysmography (BOD POD®). Crude and adjusted analyses of the association between birth order and number of siblings with body composition were performed using linear regression. All analyses were stratified by the adolescent sex. The means of BMI, fat mass index and fat-free mass index among adolescents were 23.4 (sd 4.5) kg/m², 6.1 (sd 3.9) kg/m² and 17.3 (sd 2.5) kg/m², respectively. In adjusted models, the total siblings remained inversely associated with fat mass index (β = - 0.37 z-scores, 95 % CI - 0.52, - 0.23) and BMI in boys (β = - 0.39 z-scores, 95 % CI - 0.55, - 0.22). Fat-free mass index was related to the total siblings in girls (β = 0.06 z-scores, 95 % CI - 0.04, 0.17). This research has found that number of total siblings, and not birth order, is related to the fat mass index, fat-free mass index and BMI in adolescents. It suggests the need for early prevention of obesity or fat mass accumulation in only children.

  7. Influence of the multipole order of the source on the decay of an inertial wave beam in a rotating fluid

    Science.gov (United States)

    Machicoane, Nathanael; Cortet, Pierre-Philippe; Voisin, Bruno; Moisy, Frederic

    2015-11-01

    Inertial wave beams emitted from localized sources are relevant to a broad range of geo and astrophysical flows. These beams are excited at critical lines, where the local slope of solid boundaries equals the propagation angle of the wave, in rotating fluid domains affected by a global harmonic forcing (e.g. precession, libration, tidal motion). We show here theoretically and experimentally that the decay of the amplitude of such wave beams depends on the multipole order of the source. We analyze the far-field viscous decay of a two-dimensional inertial wave beam emitted by a harmonic line source in a rotating fluid. By identifying the relevant conserved quantities along the wave beam, we show how the beam structure and decay exponent are governed by the multipole order of the source. Two wavemakers are considered experimentally, a pulsating and an oscillating cylinder, aiming to produce a monopole and a dipole source, respectively. The relevant conserved quantity which discriminates between these two sources is the instantaneous flow rate along the wave beam, which is non-zero for the monopole and zero for the dipole. For each source, the beam structure and decay exponent, measured using particle image velocimetry, are found in good agreement with the predictions.

  8. Influence of the precursors in the morphology, structure, vibrational order and optical gap of nano structured Zn O

    Energy Technology Data Exchange (ETDEWEB)

    Jurado, J. F.; Londono C, A.; Jurado L, F. F.; Romero S, J. D., E-mail: jfjurado@unal.edu.co [Universidad Nacional de Colombia, Laboratorio de Propiedades Termicas Dielectricas de Compositos, A. A. 127, Manizales (Colombia)

    2014-07-01

    The synthesis of Zn O by reaction in solid state from two precursor salts (zinc acetate and zinc sulfate), presented significant differences concerning morphology, structure, vibrational order and optical gap. As well as covering in the size of the compounds, a homogeneous distribution of nanoparticles of 21±3 nm and micro stars of 1.03±0.19 μm respectively. The Zn O showed a structural phase with a vibrational state of the hexagonal type (wurtzite). The variation in the morphology due to the precursor is attributed to the disorder within of lattice, which contributes to vibrational changes and is correlated to the degrees of freedom of molecules. Measurements of UV-Vis of nanoparticles displayed a band gap (E{sub g}) lower than the one reported for the bulk material. The structural characterization of the compounds was carried out by using a X-ray Bruker D8 Advance diffractometer. The vibrational order was assessed throughout micro-Raman with a monochromatic radiation source of 473 nm). (Author)

  9. Quantification of the first-order high-pass filter's influence on the automatic measurements of the electrocardiogram.

    Science.gov (United States)

    Isaksen, Jonas; Leber, Remo; Schmid, Ramun; Schmid, Hans-Jakob; Generali, Gianluca; Abächerli, Roger

    2017-02-01

    The first-order high-pass filter (AC coupling) has previously been shown to affect the ECG for higher cut-off frequencies. We seek to find a systematic deviation in computer measurements of the electrocardiogram when the AC coupling with a 0.05 Hz first-order high-pass filter is used. The standard 12-lead electrocardiogram from 1248 patients and the automated measurements of their DC and AC coupled version were used. We expect a large unipolar QRS-complex to produce a deviation in the opposite direction in the ST-segment. We found a strong correlation between the QRS integral and the offset throughout the ST-segment. The coefficient for J amplitude deviation was found to be -0.277 µV/(µV⋅s). Potential dangerous alterations to the diagnostically important ST-segment were found. Medical professionals and software developers for electrocardiogram interpretation programs should be aware of such high-pass filter effects since they could be misinterpreted as pathophysiology or some pathophysiology could be masked by these effects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Diffusion mobility of the hydrogen atom with allowance for the anharmonic attenuation of migrating atom state

    Energy Technology Data Exchange (ETDEWEB)

    Kashlev, Y.A., E-mail: yakashlev@yandex.ru

    2017-04-15

    Evolution of vibration relaxation of hydrogen atoms in metals with the close-packed lattice at high and medium temperatures is investigated based on non-equilibrium statistical thermodynamics, in that number on using the retarded two-time Green function method. In accordance with main kinetic equation – the generalized Fokker- Plank- Kolmogorov equation, anharmonism of hydrogen atoms vibration in potential wells does not make any contribution to collision effects. It influences the relaxation processes at the expense of interference of fourth order anharmonism with single-phonon scattering on impurity hydrogen atoms. Therefore, the total relaxation time of vibration energy of system metal-hydrogen is written as a product of two factors: relaxation time of system in harmonic approximation and dimensionless anharmonic attenuation of quantum hydrogen state.

  11. Hydrogen uptake in vanadium first wall structures

    Energy Technology Data Exchange (ETDEWEB)

    Simonen, E.P.; Jones, R.H. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    Evaluation of hydrogen sources and transport are needed to assess the mechanical integrity of V structures. Two sources include implantation and transmutation. The proposed coatings for the DEMO and ITER first wall strongly influence retention of hydrogen isotopes. Upper limit calculations of hydrogen inventory were based on recycling to the plasma and an impermeable coolant-side coating. Hydrogen isotope concentrations in V approaching 1,000 appm may be activated.

  12. Influence of the order of boron and phosphorus diffusion on the fabrication of thin bifacial silicon solar cells

    Science.gov (United States)

    da Conceição Osório, Vanessa; Moehlecke, Adriano; Zanesco, Izete

    2016-10-01

    The aim of this paper is to analyze the fabrication process of thin bifacial silicon solar cells concerning the order of diffusions to form p+ and n+ regions. The n+pp+ structure with the p+ selective region was implemented by using thin solar grade Czochralski silicon wafers. The whole rear face was doped with boron deposited by spin-on and thermally diffused and an Al metal grid was screen-printed and diffused. The phosphorus diffusion after the boron one produced the thinner n+ emitter and thinner dead layer, which allow the manufacturing of more efficient solar cells. Furthermore, the phosphorus diffusion at the end of processing promoted gettering, enhancing the minority charge carrier lifetime. Solar cells with the phosphorus diffusion after the boron one reached front and rear efficiencies of 14.0% and 10.4%, respectively, without any surface passivation.

  13. Modelling and experimental checking of the influence of substrate concentration on the first order kinetic constant in photo-processes.

    Science.gov (United States)

    Gómez, M; Murcia, M D; Gómez, E; Ortega, S; Sánchez, A; Thaikovskaya, O; Briantceva, N

    2016-12-01

    Most photoprocesses follow a pseudo first order kinetic law and, commonly, the kinetic parameter depends on the initial concentration of the substrate. In this work, a kinetic model, which explains this dependence on the substrate concentration and on the other operational variables, has been developed. In the model, mass transfer of substrate from the bulk solution to the wall of the photoreactor was assumed as the step determining the rate of the process. To check the model, methylene blue (MB) has been used as model substrate and photodegradation experiments have been carried out in an exciplex KrCl flow-through photoreactor, It was observed that the methylene blue conversion improved with a decrease in its initial concentration, in good agreement with the model. Also, by fitting the experimental data to the model, high correlation coefficients and a high degree of agreement between experimental and calculated conversion was obtained, which validates the model. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Influence of Teaching Strategies and its Order of Exposure on Pre-Clinical Teeth Arrangement - A Pilot Study.

    Science.gov (United States)

    Jeyapalan, Karthigeyan; Mani, Uma Maheswari; Christian, Jayanth; Seenivasan, Madhan Kumar; Natarajan, Parthasarathy; Vaidhyanathan, Anand Kumar

    2016-10-01

    Teeth arrangement is a vital skill for the undergraduate dental student. The attainment of skills depends largely on the methodology of teaching. In a dental curriculum, the students are exposed to a wide variety of inputs and teaching methodologies from different sources. The educational unit in dental school must identify the sequence of teaching methods that enhance the learning and practising ability of students. The aim of this study was to evaluate the effectiveness of three different teaching methodologies for teeth arrangement and compare the differences between the orders of exposure to each teaching methodology on the development of teeth arrangement skills. The first year B.D.S students were study participants and were divided into three groups A, B, C. They were exposed to three teaching patterns namely live demonstration with video assisted teaching, group discussion with hand-outs and lectures with power point presentation. After each teaching methodology, their skill was assessed. The groups were exposed to three methodologies in different order for three arrangements. The scores obtained were analysed using Kruskal Wallis rank sum test and Dunn test for statistical significance. Significantly higher scores in the teeth arrangement procedure were obtained by the Group A students who were exposed initially to live demonstration with video-assisted teaching. Difference in the scores was noted among and within the groups. The difference between Group A and Group C was statistically significant after both first and third teeth arrangement (p=0.0031, p=0.0057). The study suggests each pre-clinical practice should begin with a live demonstration to enhance immediate learning absorption followed by lectures with power point presentation and group discussion for retention of knowledge and memory retrieval.

  15. The influence of trial order on learning from reward vs. punishment in a probabilistic categorization task: experimental and computational analyses.

    Science.gov (United States)

    Moustafa, Ahmed A; Gluck, Mark A; Herzallah, Mohammad M; Myers, Catherine E

    2015-01-01

    Previous research has shown that trial ordering affects cognitive performance, but this has not been tested using category-learning tasks that differentiate learning from reward and punishment. Here, we tested two groups of healthy young adults using a probabilistic category learning task of reward and punishment in which there are two types of trials (reward, punishment) and three possible outcomes: (1) positive feedback for correct responses in reward trials; (2) negative feedback for incorrect responses in punishment trials; and (3) no feedback for incorrect answers in reward trials and correct answers in punishment trials. Hence, trials without feedback are ambiguous, and may represent either successful avoidance of punishment or failure to obtain reward. In Experiment 1, the first group of subjects received an intermixed task in which reward and punishment trials were presented in the same block, as a standard baseline task. In Experiment 2, a second group completed the separated task, in which reward and punishment trials were presented in separate blocks. Additionally, in order to understand the mechanisms underlying performance in the experimental conditions, we fit individual data using a Q-learning model. Results from Experiment 1 show that subjects who completed the intermixed task paradoxically valued the no-feedback outcome as a reinforcer when it occurred on reinforcement-based trials, and as a punisher when it occurred on punishment-based trials. This is supported by patterns of empirical responding, where subjects showed more win-stay behavior following an explicit reward than following an omission of punishment, and more lose-shift behavior following an explicit punisher than following an omission of reward. In Experiment 2, results showed similar performance whether subjects received reward-based or punishment-based trials first. However, when the Q-learning model was applied to these data, there were differences between subjects in the reward

  16. The influence of temperature and seawater carbonate saturation state on 13C–18O bond ordering in bivalve mollusks

    Directory of Open Access Journals (Sweden)

    R. A. Eagle

    2013-07-01

    Full Text Available The shells of marine mollusks are widely used archives of past climate and ocean chemistry. Whilst the measurement of mollusk δ18O to develop records of past climate change is a commonly used approach, it has proven challenging to develop reliable independent paleothermometers that can be used to deconvolve the contributions of temperature and fluid composition on molluscan oxygen isotope compositions. Here we investigate the temperature dependence of 13C–18O bond abundance, denoted by the measured parameter Δ47, in shell carbonates of bivalve mollusks and assess its potential to be a useful paleothermometer. We report measurements on cultured specimens spanning a range in water temperatures of 5 to 25 °C, and field collected specimens spanning a range of −1 to 29 °C. In addition we investigate the potential influence of carbonate saturation state on bivalve stable isotope compositions by making measurements on both calcitic and aragonitic specimens that have been cultured in seawater that is either supersaturated or undersaturated with respect to aragonite. We find a robust relationship between Δ47 and growth temperature. We also find that the slope of a linear regression through all the Δ47 data for bivalves plotted against seawater temperature is significantly shallower than previously published inorganic and biogenic carbonate calibration studies produced in our laboratory and go on to discuss the possible sources of this difference. We find that changing seawater saturation state does not have significant effect on the Δ47 of bivalve shell carbonate in two taxa that we examined, and we do not observe significant differences between Δ47-temperature relationships between calcitic and aragonitic taxa.

  17. Florida Hydrogen Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Block, David L

    2013-06-30

    monitoring at any facility engaged in transport, handling and use of hydrogen. Development of High Efficiency Low Cost Electrocatalysts for Hydrogen Production and PEM Fuel Cell Applications ? M. Rodgers, Florida Solar Energy Center The objective of this project was to decrease platinum usage in fuel cells by conducting experiments to improve catalyst activity while lowering platinum loading through pulse electrodeposition. Optimum values of several variables during electrodeposition were selected to achieve the highest electrode performance, which was related to catalyst morphology. Understanding Mechanical and Chemical Durability of Fuel Cell Membrane Electrode Assemblies ? D. Slattery, Florida Solar Energy Center The objective of this project was to increase the knowledge base of the degradation mechanisms for membranes used in proton exchange membrane fuel cells. The results show the addition of ceria (cerium oxide) has given durability improvements by reducing fluoride emissions by an order of magnitude during an accelerated durability test. Production of Low-Cost Hydrogen from Biowaste (HyBrTec?) ? R. Parker, SRT Group, Inc., Miami, FL This project developed a hydrogen bromide (HyBrTec?) process which produces hydrogen bromide from wet-cellulosic waste and co-produces carbon dioxide. Eelectrolysis dissociates hydrogen bromide producing recyclable bromine and hydrogen. A demonstration reactor and electrolysis vessel was designed, built and operated. Development of a Low-Cost and High-Efficiency 500 W Portable PEMFC System ? J. Zheng, Florida State University, H. Chen, Bing Energy, Inc. The objectives of this project were to develop a new catalyst structures comprised of highly conductive buckypaper and Pt catalyst nanoparticles coated on its surface and to demonstrate fuel cell efficiency improvement and durability and cell cost reductions in the buckypaper based electrodes. Development of an Interdisciplinary Hydrogen and Fuel Cell Technology Academic Program ? J

  18. Influence of bio-methane and hydrogen on the microbiology of underground gas storage. Literature study; Einfluss von Biogas und Wasserstoff auf die Mikrobiologie in Untertagegasspeichern. Literaturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M.; Ballerstedt, H. [MicroPro GmbH, Gommern (Germany)

    2013-05-15

    The given literature review addresses possible impacts and risks of microbiological processes in underground storage facilities, with regard to the planned partial feed-in of hydrogen and bio-methane. The multiple, possible microbial metabolic pathways are presented, practical aspects of ecological parameters of reservoir microbiology, interactions with the rock matrix and formation waters, contamination risks and possible technical consequences for storage management are discussed. Although an application transfer of experiences gained from pure hydrogen or town gas storage has certain limitations, microbiological risks associated with the intended partial feed-in of hydrogen and bio-methane into gas system can be estimated to a certain extent. Since hydrogen is an energy source for many anaerobic metabolic processes, a substantial risk potential for underground gas storages, especially porous reservoirs exists. Many underground storages in Germany provide all necessary conditions for a rapid and complete microbial degradation process of the injected hydrogen con-tent. Therefore, an uncritical concentration limit for hydrogen proportion cannot be specified. Rapid hydrogen consumption by methanogenic and sulfate-reducing prokaryotes can cause consider-able technical and economic consequences, such as formation of sulfide (H{sub 2}S), microbial induced corrosion (MIC) or reduction of formation permeability. The extent of possible negative effects and whether specific low-risk reservoirs exist, are currently subject to speculation. A feed-in of bio-methane is considered less problematic, if there is a way to eliminate the risk of emission of microorganisms. In view of the numerous identified risks, it seems worthwhile to consider alternatives to the direct feed-in of hydrogen into the natural gas network, such as the possibility of pure hydrogen storage in selected caverns or a prior.

  19. Enhanced Hydrogen Dipole Physisorption, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Channing [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2014-01-03

    The hydrogen gas adsorption effort at Caltech was designed to probe and apply our understanding of known interactions between molecular hydrogen and adsorbent surfaces as part of a materials development effort to enable room temperature storage of hydrogen at nominal pressure. The work we have performed over the past five years has been tailored to address the outstanding issues associated with weak hydrogen sorbent interactions in order to find an adequate solution for storage tank technology.

  20. MDMA ('Ecstasy') and methamphetamine combined: order of administration influences hyperthermic and long-term adverse effects in female rats.

    Science.gov (United States)

    Clemens, Kelly J; Cornish, Jennifer L; Li, Kong M; Hunt, Glenn E; McGregor, Iain S

    2005-08-01

    The acute and long-term dangers of 3,4-methylenedioxymethamphetamine (MDMA, 'Ecstasy') and methamphetamine (METH) are well described individually, but their effect in combination is largely unknown. Here groups of female rats were given four MDMA or METH injections within a single session with each injection separated by 2h. Treatments included MDMA only, METH only, MDMA and METH in a cocktail (MDMA/METH), MDMA (two injections) followed by METH (two injections) (MDMA-->METH), or METH followed by MDMA (METH-->MDMA). Each injection involved 4mg/kg of total drug. Drug administration occurred at a high ambient temperature of 28 degrees C. All treatments produced hyperactivity while the treatments where MDMA was administered first (MDMA, MDMA-->METH and MDMA/METH) produced hyperthermia. All treatments involving METH caused significant head weaving. Six weeks after drug treatment all groups showed reduced social interaction relative to controls. MDMA/METH treatment was associated with reduced swimming in the forced swim test. MDMA given alone caused 5-HT depletion in several brain regions while METH given alone caused dopamine depletion in the striatum. The three treatments involving MDMA and METH combinations caused significant depletion of serotonin, dopamine and noradrenaline in several brain regions. Interestingly, the MDMA-->METH treatment produced greater hippocampal and cortical 5-HT depletion than the METH-->MDMA treatment suggesting an effect of order. These results extend our recent findings of additive toxic effects when METH is combined with MDMA. This has potentially important implications for party drug users who appear to frequently use this combination.

  1. Influence of ligation method on friction resistance of lingual brackets with different second-order angulations: an in vitro study

    Directory of Open Access Journals (Sweden)

    Graziane Olímpio Pereira

    Full Text Available ABSTRACT Objective: To evaluate stainless steel archwire static friction in active and passive self-ligating lingual and conventional brackets with second-order angulations. Methods: Two conventional lingual brackets for canines (STb light/Ormco; PSWb/Tecnident, and two self-ligating brackets, one active (In-Ovation L/GAC and the other passive (3D/ Forestadent, were evaluated. A stainless steel archwire was used at 0°, 3° and 5° angulations. Metal ligatures, conventional elastic ligatures, and low friction elastic ligatures were also tested. A universal testing machine applied friction between brackets and wires, simulating sliding mechanics, to produce 2-mm sliding at 3 mm/minute speed. Results: Two-way analysis of variance demonstrated a significant effect of the interaction between brackets and angulations (p < 0.001. Tukey test indicated that the highest frictional resistance values were observed at 5° angulation for In-Ovation L, PSWb bracket with non conventional ligature, and STb bracket with metal ligature. As for 3D, PSWb with conventional or metal ligatures, and STb brackets with non conventional ligature, showed significantly lower static frictional resistance with 0° angulation. At 0° angulation, STb brackets with metal ties, In-Ovation L brackets and 3D brackets had the lowest frictional resistance. Conclusions: As the angulation increased from 0° to 3°, static friction resistance increased. When angulation increased from 3° to 5°, static friction resistance increased or remained the same. Self-ligating 3D and In-Ovation L brackets, as well as conventional STb brackets, seem to be the best option when sliding mechanics is used to perform lingual orthodontic treatment.

  2. Influence of ligation method on friction resistance of lingual brackets with different second-order angulations: an in vitro study

    Science.gov (United States)

    Pereira, Graziane Olímpio; Gimenez, Carla Maria Melleiro; Prieto, Lucas; Prieto, Marcos Gabriel do Lago; Basting, Roberta Tarkany

    2016-01-01

    ABSTRACT Objective: To evaluate stainless steel archwire static friction in active and passive self-ligating lingual and conventional brackets with second-order angulations. Methods: Two conventional lingual brackets for canines (STb light/Ormco; PSWb/Tecnident), and two self-ligating brackets, one active (In-Ovation L/GAC) and the other passive (3D/ Forestadent), were evaluated. A stainless steel archwire was used at 0°, 3° and 5° angulations. Metal ligatures, conventional elastic ligatures, and low friction elastic ligatures were also tested. A universal testing machine applied friction between brackets and wires, simulating sliding mechanics, to produce 2-mm sliding at 3 mm/minute speed. Results: Two-way analysis of variance demonstrated a significant effect of the interaction between brackets and angulations (p bracket with non conventional ligature, and STb bracket with metal ligature. As for 3D, PSWb with conventional or metal ligatures, and STb brackets with non conventional ligature, showed significantly lower static frictional resistance with 0° angulation. At 0° angulation, STb brackets with metal ties, In-Ovation L brackets and 3D brackets had the lowest frictional resistance. Conclusions: As the angulation increased from 0° to 3°, static friction resistance increased. When angulation increased from 3° to 5°, static friction resistance increased or remained the same. Self-ligating 3D and In-Ovation L brackets, as well as conventional STb brackets, seem to be the best option when sliding mechanics is used to perform lingual orthodontic treatment. PMID:27653262

  3. Factors Influencing the Stable Oxygen and Hydrogen Isotopic Composition (δ 18O and δ D) of a Subarctic Freshwater Lake Ecosystem

    Science.gov (United States)

    Wang, Y.; Wooller, M. J.

    2005-12-01

    Previous studies have shown that the stable oxygen and hydrogen isotopic compositions (δ 18O and δD) in various animal tissues can be used to examine past climates and animal migration pattern. Little attention has been paid to the relative roles of diet and water influencing the overall δ 18O and δD of animal tissues in freshwater ecosystems. It is unclear whether different trophic levels in a freshwater lake ecosystem have an identical relationship to the water that surrounds them. The δ18O and δD values of animal tissues may be controlled by numerous different factors, including metabolic and biosynthetic isotopic fractionation and variations of δ 18O and δD in the food available. We began to examine these issues by analyzing the δ 18O and δD throughout a freshwater aquatic ecosystem at Smith Lake in Alaska. We collected samples representing primary producers and consumers (primary and secondary). Samples included green algae, various aquatic plants, such as Nuphar variegatum (water lily), Polygonum amphibium (water smartweed), Carex utriculata (sedge), Utricularia vulgaris (common bladderwort), Typha latifolia (common cattail), and a range of aquatic invertebrates, including Chironomus. sp (midge), Zygoptera (damselfly), Anisoptera (dragonfly), Dytiscidae (diving beetle) and Euhirudinea (leeches). The δ 18O and δD of Smith Lake water were ~-13.5e and -129.0e, respectively, and we present the δ 18O and δD of the rest of the ecosystem relative to these data. For instance, the δ 18O of chironomus sp. was ~12.1, which is greater than the of the lake water. Preliminary results suggest the extent of the fractionation between δ 18O of chironomids vs. lake water δ 18O is consistent with previous studies. Our data provide an insight into the range of variations that could be expected within a single freshwater ecosystem.

  4. California Hydrogen Infrastructure Project

    Energy Technology Data Exchange (ETDEWEB)

    Heydorn, Edward C

    2013-03-12

    Air Products and Chemicals, Inc. has completed a comprehensive, multiyear project to demonstrate a hydrogen infrastructure in California. The specific primary objective of the project was to demonstrate a model of a real-world retail hydrogen infrastructure and acquire sufficient data within the project to assess the feasibility of achieving the nation's hydrogen infrastructure goals. The project helped to advance hydrogen station technology, including the vehicle-to-station fueling interface, through consumer experiences and feedback. By encompassing a variety of fuel cell vehicles, customer profiles and fueling experiences, this project was able to obtain a complete portrait of real market needs. The project also opened its stations to other qualified vehicle providers at the appropriate time to promote widespread use and gain even broader public understanding of a hydrogen infrastructure. The project engaged major energy companies to provide a fueling experience similar to traditional gasoline station sites to foster public acceptance of hydrogen. Work over the course of the project was focused in multiple areas. With respect to the equipment needed, technical design specifications (including both safety and operational considerations) were written, reviewed, and finalized. After finalizing individual equipment designs, complete station designs were started including process flow diagrams and systems safety reviews. Material quotes were obtained, and in some cases, depending on the project status and the lead time, equipment was placed on order and fabrication began. Consideration was given for expected vehicle usage and station capacity, standard features needed, and the ability to upgrade the station at a later date. In parallel with work on the equipment, discussions were started with various vehicle manufacturers to identify vehicle demand (short- and long-term needs). Discussions included identifying potential areas most suited for hydrogen fueling

  5. The common genetic influence over processing speed and white matter microstructure: Evidence from the Old Order Amish and Human Connectome Projects.

    Science.gov (United States)

    Kochunov, Peter; Thompson, Paul M; Winkler, Anderson; Morrissey, Mary; Fu, Mao; Coyle, Thomas R; Du, Xiaoming; Muellerklein, Florian; Savransky, Anya; Gaudiot, Christopher; Sampath, Hemalatha; Eskandar, George; Jahanshad, Neda; Patel, Binish; Rowland, Laura; Nichols, Thomas E; O'Connell, Jeffrey R; Shuldiner, Alan R; Mitchell, Braxton D; Hong, L Elliot

    2016-01-15

    Speed with which brain performs information processing influences overall cognition and is dependent on the white matter fibers. To understand genetic influences on processing speed and white matter FA, we assessed processing speed and diffusion imaging fractional anisotropy (FA) in related individuals from two populations. Discovery analyses were performed in 146 individuals from large Old Order Amish (OOA) families and findings were replicated in 485 twins and siblings of the Human Connectome Project (HCP). The heritability of processing speed was h(2)=43% and 49% (both p<0.005), while the heritability of whole brain FA was h(2)=87% and 88% (both p<0.001), in the OOA and HCP, respectively. Whole brain FA was significantly correlated with processing speed in the two cohorts. Quantitative genetic analysis demonstrated a significant degree to which common genes influenced joint variation in FA and brain processing speed. These estimates suggested common sets of genes influencing variation in both phenotypes, consistent with the idea that common genetic variations contributing to white matter may also support their associated cognitive behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Influence of applied electric fields on the electron-related second and third-order nonlinear optical responses in two dimensional elliptic quantum dots

    Science.gov (United States)

    Giraldo-Tobón, Eugenio; Ospina, Walter; Miranda-Pedraza, Guillermo L.; Mora-Ramos, Miguel E.

    2015-07-01

    The coefficients of the second-order nonlinear optical rectification and the generation of second and third harmonics, related to electron energy transitions in a two-dimensional elliptical quantum dot are calculated. The conduction band states are obtained using the finite element method to numerically solve the effective mass Schrödinger differential equation in the parabolic approximation, including the influence of an externally applied static electric field. It comes about that the geometry of the ellipse has a strong influence on the optical response, being the large eccentricity case the more favorable one. Furthermore, it is shown that the application of an electric field is of most importance for achieving well-resolved higher harmonics signals.

  7. Interfacial Hydrogen Bonds and Their Influence Mechanism on Increasing the Thermal Stability of Nano-SiO2-Modified Meta-Aramid Fibres

    National Research Council Canada - National Science Library

    Chao Tang; Xu Li; Zhiwei Li; Jian Hao

    2017-01-01

    For further analysis of the effect of nano-doping on the properties of high polymers and research into the mechanism behind modified interfacial hydrogen bonds, a study on the formation probability...

  8. Hydrogen program overview

    Energy Technology Data Exchange (ETDEWEB)

    Gronich, S. [Dept. of Energy, Washington, DC (United States). Office of Utility Technologies

    1997-12-31

    This paper consists of viewgraphs which summarize the following: Hydrogen program structure; Goals for hydrogen production research; Goals for hydrogen storage and utilization research; Technology validation; DOE technology validation activities supporting hydrogen pathways; Near-term opportunities for hydrogen; Market for hydrogen; and List of solicitation awards. It is concluded that a full transition toward a hydrogen economy can begin in the next decade.

  9. Influences of the land use pattern on water quality in low-order streams of the Dongjiang River basin, China: A multi-scale analysis.

    Science.gov (United States)

    Ding, Jiao; Jiang, Yuan; Liu, Qi; Hou, Zhaojiang; Liao, Jianyu; Fu, Lan; Peng, Qiuzhi

    2016-05-01

    Understanding the relationships between land use patterns and water quality in low-order streams is useful for effective landscape planning to protect downstream water quality. A clear understanding of these relationships remains elusive due to the heterogeneity of land use patterns and scale effects. To better assess land use influences, we developed empirical models relating land use patterns to the water quality of low-order streams at different geomorphic regions across multi-scales in the Dongjiang River basin using multivariate statistical analyses. The land use pattern was quantified in terms of the composition, configuration and hydrological distance of land use types at the reach buffer, riparian corridor and catchment scales. Water was sampled under summer base flow at 56 low-order catchments, which were classified into two homogenous geomorphic groups. The results indicated that the water quality of low-order streams was most strongly affected by the configuration metrics of land use. Poorer water quality was associated with higher patch densities of cropland, orchards and grassland in the mountain catchments, whereas it was associated with a higher value for the largest patch index of urban land use in the plain catchments. The overall water quality variation was explained better by catchment scale than by riparian- or reach-scale land use, whereas the spatial scale over which land use influenced water quality also varied across specific water parameters and the geomorphic basis. Our study suggests that watershed management should adopt better landscape planning and multi-scale measures to improve water quality. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Hydrogen usage

    Energy Technology Data Exchange (ETDEWEB)

    1942-10-22

    This short tabular report listed the number of m/sup 3/ of hydrogen required for a (metric) ton of product for various combinations of raw material and product in a hydrogenation procedure. In producing auto gasoline, bituminous coal required 2800 m/sup 3/, brown coal required 2400 m/sup 3/, high-temperature-carbonization tar required 2100 m/sup 3/, bituminous coal distillation tar required 1300 m/sup 3/, brown-coal low-temperature-carbonization tar required 850 m/sup 3/, petroleum residues required 900 m/sup 3/, and gas oil required 500 m/sup 3/. In producing diesel oil, brown coal required 1900 m/sup 3/, whereas petroleum residues required 500 m/sup 3/. In producing diesel oil, lubricants, and paraffin by the TTH (low-temperature-hydrogenation) process, brown-coal low-temperature-carbonization tar required 550 m/sup 3/. 1 table.

  11. SNV's modes of ordering

    NARCIS (Netherlands)

    Hummel, John; Duim, van der Rene

    2016-01-01

    This article adopts an aidnographic approach to examine how internal organizational modes of ordering have influenced tourism development practices of SNV Netherlands Development Organisation (SNV). Our research revealed six modes of ordering: administration, project management, enterprising,

  12. Hierarchical order of influence of mix variables affecting compressive strength of sustainable concrete containing fly ash, copper slag, silica fume, and fibres.

    Science.gov (United States)

    Natarajan, Sakthieswaran; Karuppiah, Ganesan

    2014-01-01

    Experiments have been conducted to study the effect of addition of fly ash, copper slag, and steel and polypropylene fibres on compressive strength of concrete and to determine the hierarchical order of influence of the mix variables in affecting the strength using cluster analysis experimentally. While fly ash and copper slag are used for partial replacement of cement and fine aggregate, respectively, defined quantities of steel and polypropylene fibres were added to the mixes. It is found from the experimental study that, in general, irrespective of the presence or absence of fibres, (i) for a given copper slag-fine aggregate ratio, increase in fly ash-cement ratio the concrete strength decreases and with the increase in copper slag-sand ratio also the rate of strength decrease and (ii) for a given fly ash-cement ratio, increase in copper slag-fine aggregate ratio increases the strength of the concrete. From the cluster analysis, it is found that the quantities of coarse and fine aggregate present have high influence in affecting the strength. It is also observed that the quantities of fly ash and copper slag used as substitutes have equal "influence" in affecting the strength. Marginal effect of addition of fibres in the compression strength of concrete is also revealed by the cluster analysis.

  13. Versatile Hydrogen

    Indian Academy of Sciences (India)

    Hydrogen is probably the most intriguing ele- ment in the periodic table. Although it is only the seventh most abundant element on earth, it is the most abundant element in the uni- verse. It combines with almost all the ele- ments of the periodic table, except for a few transition elements, to form binary compounds of the type E.

  14. Modelling of flame propagation in the gasoline fuelled Wankel rotary engine with hydrogen additives

    Science.gov (United States)

    Fedyanov, E. A.; Zakharov, E. A.; Prikhodkov, K. V.; Levin, Y. V.

    2017-02-01

    Recently, hydrogen has been considered as an alternative fuel for a vehicles power unit. The Wankel engine is the most suitable to be adapted to hydrogen feeding. A hydrogen additive helps to decrease incompleteness of combustion in the volumes near the apex of the rotor. Results of theoretical researches of the hydrogen additives influence on the flame propagation in the combustion chamber of the Wankel rotary engine are presented. The theoretical research shows that the blend of 70% gasoline with 30% hydrogen could accomplish combustion near the T-apex in the stoichiometric mixture and in lean one. Maps of the flame front location versus the angle of rotor rotation and hydrogen fraction are obtained. Relations of a minimum required amount of hydrogen addition versus the engine speed are shown on the engine modes close to the average city driving cycle. The amount of hydrogen addition that could be injected by the nozzle with different flow sections is calculated in order to analyze the capacity of the feed system.

  15. Influence of temperature on the hydrogen evolution reaction on stainless steels in LiBr solution by means of polarization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Guinon Pina, V.; Igual-Munoz, A.; Garcia-Anton, J. [Valencia Univ. Politecnica, Dept. de Ingenieria Quimica y Nuclear. ETSI Industriales, Valencia (Spain)

    2009-07-01

    Lithium Bromide aqueous solutions used as absorbent in refrigeration machines can cause serious corrosion problems which also facilitate the hydrogen evolution reaction (HER) in the cathodic regions. Hydrogen formation is an important problem in the operating conditions of adsorption machines because they operate under low pressure conditions. Hydrogen generation makes pressure to increase and as a consequence efficiency decreases. Duplex Stainless Steels (DSS) are iron-based alloys with a two-phase microstructure: austenite and delta ferrite in approximately similar percentages. DSS find increasing use as an alternative to austenitic stainless steels, particularly where aggressive anions such as bromide are present in high concentrations. The objective of the present work is to study the effect of temperature on the hydrogen evolution reaction (HER) of two different stainless steels, Austenitic and Duplex steels, using different electrochemical techniques: Open Circuit Potential (OCP), potentiodynamic and galvano-static measurements and image digital analysis. The HER was studied in 992 g/l LiBr at three different temperatures (25, 50 and 75 C). The results showed that the electrocatalytic activity for the HER increased with temperature. The energy consumption for hydrogen generation on Austenitic Stainless Steel, UNS N08031, is lower than on Duplex Stainless Steel, EN 1.4462, at the studied temperatures. (authors)

  16. Influence of pupil diameter on the relation between ocular higher-order aberration and contrast sensitivity after laser in situ keratomileusis.

    Science.gov (United States)

    Oshika, Tetsuro; Tokunaga, Tadatoshi; Samejima, Tomokazu; Miyata, Kazunori; Kawana, Keisuke; Kaji, Yuichi

    2006-04-01

    To investigate the influence of pupil diameter on the relation between induced changes in ocular higher-order wavefront aberrations and changes in contrast sensitivity by conventional laser in situ keratomileusis (LASIK) for myopia. In 215 eyes of 117 patients (age, 33.2 +/- 8.3 years) undergoing LASIK for myopia of -1.25 to -13.5 D (-5.28 +/- 2.55 D), ocular wavefront aberrations and contrast sensitivity function were determined before and 1 month after surgery. Preoperative photopic pupil diameter was measured with a digital camera. Ocular higher-order aberrations were measured for a 4-mm pupil with a Hartmann-Shack wavefront analyzer. The root-mean-square (RMS) of the third- and fourth-order Zernike coefficients was used to represent coma- and spherical-like aberration, respectively. From the contrast-sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. One hundred five eyes had a photopic pupil diameter of 4 mm or larger, and the remaining 110 had a photopic pupil diameter smaller than 4 mm. There were no statistically significant differences in the background clinical data between these two groups. In the eyes with a photopic pupil diameter of 4 mm or larger, the changes in third-order comalike aberrations did not correlate with the changes in AULCSF (Pearson correlation coefficient, r = -0.037, P = 0.723) and 10% low-contrast visual acuity (r = 0.125, P = 0.224), but fourth-order spherical-like aberrations correlated significantly with the changes in AULCSF (r = -0.229, P = 0.024) and 10% low-contrast visual acuity (r = 0.221, P = 0.038). In the eyes with photopic pupil size smaller than 4 mm, there were significant correlations between the changes in comalike aberrations and the changes in AULCSF (r = -0.487, P pupil diameter, increases in spherical-like aberration dominantly affect contrast sensitivity, whereas in eyes with smaller pupil size, changes in coma-like aberration exert greater influence on visual

  17. Transformation of hydrogen titanate nanoribbons to TiO2 nanoribbons and the influence of the transformation strategies on the photocatalytic performance

    Directory of Open Access Journals (Sweden)

    Melita Rutar

    2015-03-01

    Full Text Available The influence of the reaction conditions during the transformation of hydrogen titanate nanoribbons to TiO2 nanoribbons on the phase composition, the morphology, the appearance of the nanoribbon surfaces and their optical properties was investigated. The transformations were performed (i through a heat treatment in oxidative and reductive atmospheres in the temperature range of 400–650 °C, (ii through a hydrothermal treatment in neutral and basic environments at 160 °C, and (iii through a microwave-assisted hydrothermal treatment in a neutral environment at 200 °C. Scanning electron microscopy investigations showed that the hydrothermal processing significantly affected the nanoribbon surfaces, which became rougher, while the transformations based on calcination in either oxidative or reductive atmospheres had no effect on the morphology or on the surface appearance of the nanoribbons. The transformations performed in the reductive atmosphere, an NH3(g/Ar(g flow, and in the ammonia solution led to nitrogen doping. The nitrogen content increased with an increasing calcination temperature, as was determined by X-ray photoelectron spectroscopy. According to electron paramagnetic resonance measurements the calcination in the reductive atmosphere also resulted in a partial reduction of Ti4+ to Ti3+. The photocatalytic performance of the derived TiO2 NRs was estimated on the basis of the photocatalytic oxidation of isopropanol. After calcinating in air, the photocatalytic performance of the investigated TiO2 NRs increased with an increased content of anatase. In contrast, the photocatalytic performance of the N-doped TiO2 NRs showed no dependence on the calcination temperature. An additional comparison showed that the N-doping significantly suppressed the photocatalytic performance of the TiO2 NRs, i.e., by 3 to almost 10 times, in comparison with the TiO2 NRs derived by calcination in air. On the other hand, the photocatalytic performance of the

  18. Hydrogen in metals

    CSIR Research Space (South Africa)

    Carter, TJ

    2001-04-01

    Full Text Available The effects of hydrogen on various metals and the use of metal hydrides for hydrogen storage are discussed. The mechanisms of, and differences between, hydrogen embrittlement and hydrogen attack of ferritic steels are compared, common sources...

  19. Photovoltaic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Hiser, H.W.; Memory, S.B.; Veziroglu, T.N.; Padin, J. [Univ. of Miami, Coral Gables, FL (United States)

    1996-10-01

    This is a new project, which started in June 1995, and involves photovoltaic hydrogen production as a fuel production method for the future. In order to increase the hydrogen yield, it was decided to use hybrid solar collectors to generate D.C. electricity, as well as high temperature steam for input to the electrolyzer. In this way, some of the energy needed to dissociate the water is supplied in the form of heat (or low grade energy), to generate steam, which results in a reduction of electrical energy (or high grade energy) needed. As a result, solar to hydrogen conversion efficiency is increased. In the above stated system, the collector location, the collector tracking sub-system (i.e., orientation/rotation), and the steam temperature have been taken as variables. Five locations selected - in order to consider a variety of latitudes, altitudes, cloud coverage and atmospheric conditions - are Atlanta, Denver, Miami, Phoenix and Salt Lake City. Plain PV and hybrid solar collectors for a stationary south facing system and five different collector rotation systems have been analyzed. Steam temperatures have been varied between 200{degrees}C and 1200{degrees}C. During the first year, solar to hydrogen conversion efficiencies have been considered. The results show that higher steam temperatures, 2 dimensional tracking system, higher elevations and dryer climates causes higher conversion efficiencies. Cost effectiveness of the sub-systems and of the overall system will be analyzed during the second year. Also, initial studies will be made of an advanced high efficiency hybrid solar hydrogen production system.

  20. Influence of Pt Gate Electrode Thickness on the Hydrogen Gas Sensing Characteristics of Pt/In2O3/SiC Hetero-Junction Devices

    Directory of Open Access Journals (Sweden)

    S. Kandasamy

    2007-09-01

    Full Text Available Hetero-junction Pt/In2O3/SiC devices with different Pt thickness (30, 50 and 90nm were fabricated and their hydrogen gas sensing characteristics have been studied. Pt and In2O3 thin films were deposited by laser ablation. The hydrogen sensitivity was found to increase with decreasing Pt electrode thickness. For devices with Pt thickness of 30 nm, the sensitivity gradually increased with increasing temperature and reached a maximum of 390 mV for 1% hydrogen in air at 530°C. Atomic force microscopy (AFM analysis revealed a decrease in Pt grain size and surface roughness for increasing Pt thickness. The relationship between the gas sensing performance and the Pt film thickness and surface morphology is discussed.

  1. Permeability test and fuzzy orthogonal analysis of hydrogenated nitrile O-ring

    OpenAIRE

    Hu, Qin; Wan, Changcheng; Wang, Changxin

    2015-01-01

    In the high temperature, high pressure and high corrosive environment of the oil and gas drilling downhole, the weatherability of rubber sealing material has a great influence on the production safety. In order to study the important degree of every key environmental factor in downhole influencing the sealing performance of rubber sealing material, a new device of simulating downhole environment is designed to test the permeability of O-ring. The sample is hydrogenated nitrile O-ring and orth...

  2. Solvent effects on a Diels-Alder reaction involving a cationic diene: Consequences of the absence of hydrogen-bond interactions for accelerations in aqueous media

    NARCIS (Netherlands)

    van der Wel, Gerben K.; Wijnen, Jan W.; Engberts, Jan B.F.N.

    1996-01-01

    In order to study the influence of hydrogen-bond interactions on the accelerations of Diels-Alder reactions in water and highly aqueous mixed solvent systems, second-order rate constants for the Diels-Alder reaction of acridizinium bromide (1a) with cyclopentadiene (CP) have been measured in aqueous

  3. Ordering and interactions between Cl adatoms on Cu(111) and their influence on the local electronic properties as measured by STM and STS

    Science.gov (United States)

    Torsney, Samuel; Naydenov, Borislav; Boland, John J.

    2017-12-01

    We present a scanning tunneling microscopy/spectroscopy study of compressed Cl adlayers on Cu(111) under ultrahigh-vacuum conditions. We describe a rational scheme to assign Cl adatoms to different surface sites. The dominant electronic state visible in scanning tunneling spectroscopy (STS) corresponds to an antibonding interaction between the Cl adlayer and the copper surface. This state was observed to be 200 meV higher in energy at hcp sites compared to fcc sites, and it is attributed to the greater charge transfer to Cl adatoms at hcp sites. Although there was no STS signature associated with bridging sites, the presence of bridging Cl adatoms along the periphery of fcc domains caused a shift in the energy of the interface state in the latter. These results shed important light on the ordering and interaction between Cl adatoms on Cu(111) and their influence of the local electronic structure of the surface.

  4. The Influence of Antiobesity Media Content on Intention to Eat Healthily and Exercise: A Test of the Ordered Protection Motivation Theory

    Science.gov (United States)

    Ritland, Raeann; Rodriguez, Lulu

    2014-01-01

    This study extended the ordered protection motivation framework to determine whether exposure and attention to antiobesity media content increases people's appraisals of threat and their ability to cope with it. It also assesses whether these cognitive processes, in turn, affected people's intention to abide by the practices recommended to prevent obesity. The results of a national online survey using a nonprobability sample indicate that attention to mediated obesity and related information significantly increased people's intention to exercise as well as their overall coping appraisals (the perceived effectiveness of the recommended behaviors and their ability to perform them). Likewise, increased threat and coping appraisals were both found to significantly influence people's intention to exercise and diet. Coping (rather than threat) appraisals more strongly predicted behavioral intent. Following the attitude-behavior literature, behavioral intention was used as the most proximate predictor of actual behavior (i.e., stronger intentions increase the likelihood of behavior change). PMID:25505981

  5. Heat Pre-Treatment of Beverages Wastewater on Hydrogen Production

    Science.gov (United States)

    Uyub, S. Z.; Mohd, N. S.; Ibrahim, S.

    2017-06-01

    At present, a large variety of alternative fuels have been investigated and hydrogen gas is considered as the possible solution for the future due to its unique characteristics. Through dark fermentation process, several factors were found to have significant impact on the hydrogen production either through process enhancement or inhibition and degradation rates or influencing parameters. This work was initiated to investigate the optimum conditions for heat pre-treatment and initial pH for the dark fermentative process under mesophilic condition using a central composite design and response surface methodology (RSM). Different heat treatment conditions and pH were performed on the seed sludge collected from the anaerobic digester of beverage wastewater treatment plant. Heat treatment of inoculum was optimized at different exposure times (30, 90, 120 min), temperatures (80, 90 and 100°C) and pH (4.5, 5.5, 6.5) in order to maximize the biohydrogen production and methanogens activity inhibition. It was found that the optimum heat pre-treatment condition and pH occurred at 100°C for 50 min and the pH of 6.00. At this optimum condition the hydrogen yield was 63.0476 ml H2/mol glucose (H2 Yield) and the COD removal efficiency was 90.87%. In conclusion, it can be hypothesized that different heat treatment conditions led to differences in the initial microbial communities (hydrogen producing bacteria) which resulted in the different hydrogen yields.

  6. Influence of degree of sulfonation of BDPP upon enantioselectivity in rhodium-BDPP catalyzed hydrogenation reactions in a two phase system

    NARCIS (Netherlands)

    Lensink, Cornelis; Rijnberg, Evelien; Vries, Johannes G. de

    1997-01-01

    Asymmetric hydrogenation experiments were carried out with catalysts prepared in situ from [Rh(COD)Cl]2 and 2 eq. of a sulfonated (2S,4S)-bis-2,4-(diphenylphosphino)pentane carrying 0-4 sulfonate groups, in a two phase aqueous organic system. The effect of degree of sulfonation on enantioselectivity

  7. Influence of hydrogenation on the structural and magnetic properties of compounds based on cerium and crystallizing in the tetragonal CeFeSi-type structure

    NARCIS (Netherlands)

    Chevalier, B.; Pasturel, M.; Bobet, J. L.; Isnard, O.

    2005-01-01

    The hydrogen absorption properties of CeMnGe, CeFeSi and CeCoX (X=Si and Ge) have been investigated. Neutron powder diffraction performed on deuteride CeCoGeD indicates that D-atoms are inserted in the pseudo-tetrahedral interstices [Ce

  8. Hydrogen cyanamide on citrus: Phytotoxicity, influences on flush in potted and field trees and effects on bloom and cropload in the field

    Science.gov (United States)

    Bloom in individual citrus trees typically continues for more than a month in south Florida. Prolonged bloom increases susceptibility to postbloom fruit drop disease (caused by Colletotrichum acutatum) and contributes to variable fruit maturity at harvest. Hydrogen cyanamide (HCN) is used to acceler...

  9. Does Intrasession Concurrent Strength and Aerobic Training Order Influence Training-Induced Explosive Strength and V[Combining Dot Above]O2max in Prepubescent Children?

    Science.gov (United States)

    Alves, Ana R; Marta, Carlos C; Neiva, Henrique P; Izquierdo, Mikel; Marques, Mário C

    2016-12-01

    Alves, AR, Marta, C, Neiva, HP, Izquierdo, M, and Marques, MC. Does intrasession concurrent strength and aerobic training order influence training-induced explosive strength and V[Combining Dot Above]O2max in prepubescent children?. J Strength Cond Res 30(12): 3267-3277, 2016-The aim of this study was to analyze the interference of strength and aerobic training order over an 8-week period on explosive skills and maximal oxygen uptake (V[Combining Dot Above]O2max) in prepubescent children. One hundred twenty-eight prepubescent children aged 10-11 years (10.9 ± 0.5 years) were randomly selected and assigned to 1 of the 3 groups: intrasession concurrent aerobic before (GAS: n = 39) or after strength training (GSA: n = 45) or control group (GC: n = 44; no training program). The GC maintained their baseline level performance, and training-induced differences were found in the experimental groups. Increases were found in the 1-kg and 3-kg medicine ball throws: GAS: +3%, +5.5%, p ≤ 0.05, p training. All programs were effective, but GSA produced better results than GAS for muscle strength variables, and GAS produced better results than GSA for aerobic capacity variables. The present study explored an unknown issue and added useful information to the literature in this area. These training methods should be taken into consideration to optimize explosive strength and cardiorespiratory fitness training in school-based programs and sports club programs.

  10. Photophysical Properties of SrTaO2N Thin Films and Influence of Anion Ordering: A Joint Theoretical and Experimental Investigation

    KAUST Repository

    Ziani, Ahmed

    2017-04-10

    Converting photon energy into chemical energy using inorganic materials requires the successful capture of photons, exciton dissociation, and the charge carrier diffusion. This study reports a thorough analysis of the optoelectronic properties of visible-light-responsive SrTaON perovskites to quantify their absorption coefficient and the generated charge carriers\\' effective masses, dielectric constants, and electronic structures. The measurements on such intrinsic properties were attempted using both epitaxial and polycrystalline SrTaON films deposited by radiofrequency magnetron sputtering under N reactive plasma. Density functional theory calculations using the HSE06 functional provided reliable values of these optoelectronic properties. Such quantities obtained by both measurements and calculations gave excellent correspondence and provide possible variations that account for the small discrepancies observed. One of the significant factors determining the optical properties was found to be the anion ordering in the perovskite structure imposed by the cations. As a result, the different anion ordering has a noticeable influence on the optical properties and high sensitivity of the hole effective mass. Determination of relative band positions with respect to the water redox properties was also attempted by Mott-Schottky analysis. All these results offer the opportunity to understand why SrTaON possesses intrinsically all the ingredients needed for an efficient water splitting device.

  11. Chemical interesterification of soybean oil and fully hydrogenated soybean oil: Influence of the reaction time; Interesterificacao quimica de oleo de soja e oleo de soja totalmente hidrogenado: influencia do tempo de reacao

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Ana Paula Badan; Masuchi, Monise Helen; Grimaldi, Renato; Goncalves, Lireny Aparecida Guaraldo [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia de Alimentos. Dept. de Tecnologia de Alimentos], e-mail: badanribeiro@yahoo.com.br

    2009-07-01

    Chemical interesterification is an important alternative to produce zero trans fats. In practice, however, excessive reaction times are used to ensure complete randomization. This work evaluated the influence of the reaction time on the interesterification of soybean oil/fully hydrogenated soybean oil blend, carried out in the following conditions: 100 deg C, 500 rpm stirring speed, 0.4% (w/w) sodium methoxide catalyst. The triacylglycerol composition, solid fat content and melting point analysis showed that the reaction was very fast, reaching the equilibrium within 5 min. This result suggests the interesterification can be performed in substantially lower times, with reduction in process costs. (author)

  12. Extensive analysis of hydrogen costs

    Energy Technology Data Exchange (ETDEWEB)

    Guinea, D.M.; Martin, D.; Garcia-Alegre, M.C.; Guinea, D. [Consejo Superior de Investigaciones Cientificas, Arganda, Madrid (Spain). Inst. de Automatica Industrial; Agila, W.E. [Acciona Infraestructuras, Alcobendas, Madrid (Spain). Dept. I+D+i

    2010-07-01

    Cost is a key issue in the spreading of any technology. In this work, the cost of hydrogen is analyzed and determined, for hydrogen obtained by electrolysis. Different contributing partial costs are taken into account to calculate the hydrogen final cost, such as energy and electrolyzers taxes. Energy cost data is taken from official URLs, while electrolyzer costs are obtained from commercial companies. The analysis is accomplished under different hypothesis, and for different countries: Germany, France, Austria, Switzerland, Spain and the Canadian region of Ontario. Finally, the obtained costs are compared to those of the most used fossil fuels, both in the automotive industry (gasoline and diesel) and in the residential sector (butane, coal, town gas and wood), and the possibilities of hydrogen competing against fuels are discussed. According to this work, in the automotive industry, even neglecting subsidies, hydrogen can compete with fossil fuels. Hydrogen can also compete with gaseous domestic fuels. Electrolyzer prices were found to have the highest influence on hydrogen prices. (orig.)

  13. The hydrogen; L'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The hydrogen as an energy system represents nowadays a main challenge (in a scientific, economical and environmental point of view). The physical and chemical characteristics of hydrogen are at first given. Then, the challenges of an hydrogen economy are explained. The different possibilities of hydrogen production are described as well as the distribution systems and the different possibilities of hydrogen storage. Several fuel cells are at last presented: PEMFC, DMFC and SOFC. (O.M.)

  14. Hydrogenation of zirconium film by implantation of hydrogen ions

    Science.gov (United States)

    Liu, Yang; Fang, Kaihong; Lv, Huiyi; Liu, Jiwei; Wang, Boyu

    2017-03-01

    In order to understand the drive-in target in a D-D type neutron generator, it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogen-absorbing metal film. The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions. Doses of 30 keV hydrogen ions ranging from 4.30 × 1017 to 1.43 × 1018 ions cm-2 were loaded into the zirconium film through the ion beam implantation technique. Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy, atomic force microscopy and x-ray diffraction. Confirmation of the formation of δ phase zirconium hydride in the implanted samples was first made by x-ray diffraction, and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.

  15. Use of double and triple-ion irradiation to study the influence of high levels of helium and hydrogen on void swelling of 8–12% Cr ferritic-martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Kupriiyanova, Y.E., E-mail: fomenkoj@kipt.kharkov.ua [National Science Centre Kharkov Institute of Physics and Technology, 1, Akademicheskaya St., Kharkov, 61108 (Ukraine); Bryk, V.V.; Borodin, O.V.; Kalchenko, A.S.; Voyevodin, V.N.; Tolstolutskaya, G.D. [National Science Centre Kharkov Institute of Physics and Technology, 1, Akademicheskaya St., Kharkov, 61108 (Ukraine); Garner, F.A. [Radiation Effects Consulting, Richland, WA 99354 (United States)

    2016-01-15

    In accelerator-driven spallation (ADS) devices, some of the structural materials will be exposed to intense fluxes of very high energy protons and neutrons, producing not only displacement damage, but very high levels of helium and hydrogen. Unlike fission flux-spectra where most helium and hydrogen are generated by transmutation in nickel and only secondarily in iron or chromium, gas production in ADS flux-spectra are rather insensitive to alloy composition, such that Fe–Cr base ferritic alloys also generate very large gas levels. While ferritic alloys are known to swell less than austenitic alloys in fission spectra, there is a concern that high gas levels in fusion and especially ADS facilities may strongly accelerate void swelling in ferritic alloys. In this study of void swelling in response to helium and hydrogen generation, irradiation was conducted on three ferritic-martensitic steels using the Electrostatic Accelerator with External Injector (ESUVI) facility that can easily produce any combination of helium to dpa and/or hydrogen to dpa ratios. Irradiation was conducted under single, dual and triple beam modes using 1.8 MeV Cr{sup +3}, 40 keV He{sup +}, and 20 keV H{sup +}. In the first part of this study we investigated the response of dual-phase EP-450 to variations in He/dpa and H/dpa ratio, focusing first on dual ion studies and then triple ion studies, showing that there is a diminishing influence on swelling with increasing total gas content. In the second part we investigated the relative response of three alloys spanning a range of starting microstructure and composition. In addition to observing various synergisms between He and H, the most important conclusion was that the tempered martensite phase, known to lag behind the ferrite phase in swelling in the absence of gases, loses much of its resistance to void nucleation when irradiated at large gas/dpa levels.

  16. Hydrogen adsorption on rhodium

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, M.E.; Michri, A.A.; Kalish, T.V.; Pshenichnikov, A.G.; Kazarinov, V.E.

    1987-09-01

    Measurements of thermal desorption and electron work function were used to investigate the mechanism of hydrogen adsorption from the gas phase on rhodium single-crystal faces and on a polycrystalline rhodium sample at room temperatures over the pressure range from 1.3-10/sup -3/ to 1.3 x 10/sup -5/ Pa. It was found that dipoles oriented with their negative ends toward the gas phase (dipoles of type I) form more rapidly than dipoles having the opposite orientation (dipoles of type II). For formation of the latter, a mechanism is proposed according to which the rate-determining step of the overall process is the transition of reversibly adsorbed hydrogen to dipoles of type II (the spillover), which occurs at surface defects. It was shown that the kinetics of this process with respect to the individual defect obeys an equation which is zeroth order in theta/sub H/ and pressure.

  17. Hydrogen program summary Fiscal Year 1994

    Energy Technology Data Exchange (ETDEWEB)

    1995-03-01

    The annual program summary provides stakeholders within the hydrogen community with a snapshop of important advances that have occurred in the National Hydrogen Program over the fiscal year, including industry interactions and cooperation. The document will also be used to encourage additional potential industrial partners to join the Hydrogen Program Team. Fiscal Year 1994 marked a turning point for the Hydrogen Program, with a budget that grew significantly. The focus of the program was broadened to include development of hydrogen production technologies using municipal solid waste and biomass, in addition to an increased emphasis on industrial involvement and near-term demonstration projects. In order to maintain its near- and long-term balance, the Hydrogen Program will continue with basic, fundamental research that provides the long-term, high-risk, high-payoff investment in hydrogen as an energy carrier.

  18. Ethanol steam reforming over Ni/M{sub x}O{sub y}-Al{sub 2}O{sub 3} (M=Ce, La, Zr and Mg) catalysts: Influence of support on the hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Sanchez, M.C.; Navarro, R.M.; Fierro, J.L.G. [Instituto de Catalisis y Petroleoquimica, CSIC, C/ Marie Curie 2 Cantoblanco 28049 Madrid (Spain)

    2007-07-15

    Hydrogen production from ethanol reforming over alumina-supported nickel catalysts modified with Ce, Mg, Zr and La was studied. Characterization of catalysts by XRD, TPR, XRD and TPD of NH{sub 3} revealed changes in the acidity, nickel dispersion and nickel-support interaction with the type of the modifier added to Al{sub 2}O{sub 3}. The acidity of catalysts containing Mg, Ce, La and Zr additives decreased with respect to that supported on bare Al{sub 2}O{sub 3}. The trend of metal dispersion as derived from XRD and H{sub 2} chemisorption results followed the order: La{sub 2}O{sub 3}-Al{sub 2}O{sub 3}>MgO-Al{sub 2}O{sub 3}>CeO{sub 2}-Al{sub 2}O{sub 3}>Al{sub 2}O{sub 3}>ZrO{sub 2}-Al{sub 2}O{sub 3}. TPR and XPS analyses indicate the development of strong interactions between nickel species and ZrO{sub 2}, La{sub 2}O{sub 3} and CeO{sub 2} oxides added to supports. The activity measurements coupled with the physicochemical characterization data indicated the different catalysts functionality that influences on their reforming activity. Thus, the higher reforming activity for Mg-modified catalyst respect to bare Al{sub 2}O{sub 3} was explained in terms of the lower acidity and better dispersion achieved in the former, while for Ce- and Zr-promoted catalysts the improvement in intrinsic activity was ascribed to the enhancement of water adsorption/dissociation on the Ni-Ce and Ni-Zr interfaces developed on these catalysts. On the other hand, the lower intrinsic activity of La-added catalyst was explained in terms of the dilution effect caused by the presence of lanthanum on Ni surfaces. Characterization of catalysts after reaction showed differences on the amount and type of coke deposited on catalysts surfaces. La and Ce additives were found to prevent the formation of carbon filaments on nickel surfaces, which is responsible of the changes in product selectivities with reaction time observed on Ni/Al{sub 2}O{sub 3}, Ni/ZrO{sub 2}-Al{sub 2}O{sub 3} and Ni/MgO-Al{sub 2}O

  19. A Comparison of Bulk Precipitated Cerium Oxide Powders and Cerium Conversion Coatings and the Influence of Hydrogen Peroxide on Their Formation (Preprint)

    Science.gov (United States)

    2006-03-01

    thermodynamics of the cerium/water system and of the cerium/water/hydrogen peroxide system have been reviewed elsewhere 2 [25, 32]. The purpose of this...were acidified to a pH of 1.2 using 4 mmol of concentrated HClO4 (Alfa Aeser, 60 % HClO4 ). For the peroxide containing solutions, H2O2 (Fisher, 31.0

  20. Electrochemical Hydrogen Peroxide Generator

    Science.gov (United States)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  1. Magnetic effects of interstitial hydrogen in nickel

    Energy Technology Data Exchange (ETDEWEB)

    León, Andrea [Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso (Chile); Velásquez, E.A. [Facultad de Física y Centro de Investigación en Nanotecnología y Materiales Avanzados CIEN-UC, Pontificia Universidad Católica de Chile, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología CEDENNA, Santiago (Chile); Grupo de Investigación en Modelamiento y Simulación Computacional, Universidad de San Buenaventura Sec. Medellín, Medellín (Colombia); Mazo-Zuluaga, J. [Grupo de Instrumentación Científica y Microelectrónica, Grupo de Estado Sólido, IF-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Mejía-López, J. [Facultad de Física y Centro de Investigación en Nanotecnología y Materiales Avanzados CIEN-UC, Pontificia Universidad Católica de Chile, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología CEDENNA, Santiago (Chile); Florez, J.M. [Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso (Chile); and others

    2017-01-01

    Hydrogen storage in materials is among the most relevant fields when thinking about energy conversion and storage. In this work we present a study that responds to a couple of questions concerning induced electronic changes that H produces in ferromagnetic nickel (Ni) host. We calculate and explain the change of magnetic properties of Ni with different concentrations of H. Density functional theory calculations (DFT) were performed for super-cells of fcc Ni with interstitial H in octahedral sites at different concentrations. In order to physically explain the effect of magnetization diminishing as the hydrogen concentration increases, we propose a simple Stoner type of model to describe the influence of the H impurity on the magnetic properties of Ni. The exchange splitting reduction, as shown in first principles calculations, is clearly explained within this physical model. Using a paramagnetic Ni fcc band with variable number of electrons and a Stoner model allow us to obtain the correct trend for the magnetic moment of the system as a function of the H concentration. - Highlights: • We calculate and explain the change of magnetic properties of Ni with different concentrations of H. • We propose a simple Stoner type of model to describe the influence of the H impurity on the magnetic properties of Ni. • The band exchange splitting reduction as the H concentration increases, is a consequence of the competition between the band energy term (kinetic energy) and the ferromagnetic energy term (Weiss field).

  2. The Influence of Antiobesity Media Content on Intention to Eat Healthily and Exercise: A Test of the Ordered Protection Motivation Theory

    Directory of Open Access Journals (Sweden)

    Raeann Ritland

    2014-01-01

    Full Text Available This study extended the ordered protection motivation framework to determine whether exposure and attention to antiobesity media content increases people’s appraisals of threat and their ability to cope with it. It also assesses whether these cognitive processes, in turn, affected people’s intention to abide by the practices recommended to prevent obesity. The results of a national online survey using a nonprobability sample indicate that attention to mediated obesity and related information significantly increased people’s intention to exercise as well as their overall coping appraisals (the perceived effectiveness of the recommended behaviors and their ability to perform them. Likewise, increased threat and coping appraisals were both found to significantly influence people’s intention to exercise and diet. Coping (rather than threat appraisals more strongly predicted behavioral intent. Following the attitude-behavior literature, behavioral intention was used as the most proximate predictor of actual behavior (i.e., stronger intentions increase the likelihood of behavior change.

  3. Development and application of new membranes at high temperatures in order to get hydrogen from fossil fuel. Final report. Entwicklung und Einsatz neuer Membranen bei hohen Temperaturen zur Wasserstoffgewinnung aus fossilen Energietraegern. Endbericht

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, F.; Luecke, L.; Oertel, M.; Pavlidis, S.; Schmitz, J.

    1990-06-01

    The use of membranes in dehydration reactions allows hydrogen to be extracted in one process step; at the same time the yield from the reactions is increased by the product extraction. Metallic membranes of titanium/nickel and coated vanadium as well as ceramic membranes have been developed on the basis of separation layers of aluminium oxide and zeolites. Whereas the permeation rates through TiNi are around one magnitude below those of palladium, the figures for vanadium are equal to, and in some cases even exceed those of Pd. When ceramic membranes are used no high-purity hydrogen is produced, but rather the feed gas is enriched with H{sub 1} Separation factors for H{sub 1}/N{sub 2} of between 2 and 3 are achieved with {gamma}-Al{sub 2}O{sub 3} membranes, and between 3 and 6 with zeolite membranes. The use of metal membranes in a steam reforming plant results in increases in the yield of between 10 and 45% depending on the reaction pressure. The service lives of the membrane modules developed when used in a test plant are currently around 2500 hours. The calculations carried out parallel to this are a good reflection of the test results for commercial plants without membranes and laboratory system with integrated membranes. An economic appraisal has shown that the hydrogen production costs in a conventional steam reforming plant are around 5% lower than those of a system using membranes; the relationship does, however, change in favour of the steam reformer with integrated membranes if high temperatures are used as a source of heat. (orig.) With 61 refs., 16 tabs., 55 figs.

  4. Functionalized carbon nanostructures for hydrogen catalysis

    Science.gov (United States)

    Hu, Lung-Hao

    very high activity of the catalyst can be achieved raising the figure of merit for hydrogen generation nearly to its highest possible value. The catalytic performance is also related to the intrinsic activity of chemical composition of the catalyst. In the present work, the use of catalysts of a ternary composition has been discovered to enhance the activity of the catalyst. The experiments presented in this work use Pt/Pd/Ru catalyzed SiCN/CNT as the catalyst to react with sodium borohydride for the hydrogen generation. The thickness of SiCN/CNT paper is one of the factors, which influences the hydrogen generation rate: thinner papers produce higher rates of hydrogen generation. The likely reason for this phenomenon is that hydrogen bubbles can become trapped within the mesh of carbon nanotubes that constitute the paper-like structure of the catalyst. It is hypothesized that hydrogen bubbles can escape more easily from the interior of the paper if the paper is thinner. The effect of the paper thickness on the hydrogen generation rate forms the first part of the thesis. In the next phase of the thesis, thin film structures of carbon nanotubes, about 300 nm high, were created to serve as the catalyst substrates. Transition metals were deposited on to these substrates by an electrophoretic process. In these catalysts huge increases in hydrogen generation rates, relative to the CNT-paper architecture, were achieved. Indeed the Figure of Merit (FOM), expressed as liters per minute of hydrogen generated per gram of the precious metals, per unit molar concentration of NaBH4, (Lmin-1g met-1[NaBH4]-1), of these "thin film CNT" catalysts was up to three orders of magnitude greater than could be achieved with the thick CNT paper, as described in the first part of the thesis. These values for the FOM are more than two orders of magnitude greater than the highest values for hydrogen generation from NaBH4 reported in the literature. The reaction mechanism and the catalytic

  5. Fermentative hydrogen production in batch experiments using lactose, cheese whey and glucose: Influence of initial substrate concentration and pH

    Energy Technology Data Exchange (ETDEWEB)

    Davila-Vazquez, Gustavo; Alatriste-Mondragon, Felipe; Razo-Flores, Elias [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico); de Leon-Rodriguez, Antonio [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico)

    2008-10-15

    Biologically produced hydrogen using biomass and mixed bacterial cultures is one approach to generate renewable H{sub 2}. Response surface methodology (RSM) was used to study the effect of initial pH (3.88-8.12) and initial substrate concentration (0.86-29.14 g/L) on both hydrogen molar yield (HMY) and volumetric H{sub 2} production rate (VHPR). Lactose, cheese whey powder (CWP) and glucose were used as substrates and heat-treated anaerobic granular sludge as inoculum. For lactose, 3.6 mol H{sub 2}/mol lactose and 5.6 mmol H{sub 2}/L/h were found at pH 7.5 and 5 g lactose/L. CWP yielded 3.1 mol H{sub 2}/mol lactose at pH 6 and 15 g CWP/L while 8.1 mmol H{sub 2}/L/h were attained at pH 7.5 and 25 g CWP/L. Glucose yielded 1.46 mol H{sub 2}/mol substrate (pH 7.5, 5 g glucose/L), with a VHPR of 8.9 mmol H{sub 2}/L/h, at pH 8.12 and 15 g glucose/L. Acetic and butyric acids were the main organic metabolites detected. HMY and VHPR obtained in this study were found at initial pH above the reported optimum pH value for hydrogen production. These findings could be of significance when alkaline pretreatments are performed on organic feedstock by eliminating the need to lower the pH to acidic levels before fermentation start-up. (author)

  6. The influence of polar optical phonon confinement on the binding energy of a hydrogenic impurity in quantum wires in the perpendicular electric and magnetic fields

    Science.gov (United States)

    Vartanian, A. L.; Shahbandari, A.; Yeranosyan, M. A.; Kirakosyan, A. A.

    2012-03-01

    The hydrogenic impurity binding energy in cylindrical quantum well wire with a finite confining potential including both barriers of finite height and an applied electric and magnetic fields are studied. The polaron effect on the ground-state binding energy are investigated by means of Landau-Pekar variation technique. The results for the binding energy as well as polaronic correction with taking into account polar optical phonon confinement effect are obtained as a function of the applied fields for different position of the impurity. Our calculations are compared with previous results in quantum wires of comparable dimensions.

  7. Influence of the reactant carbon-hydrogen-oxygen composition on the key products of the direct gasification of dewatered sewage sludge in supercritical water.

    Science.gov (United States)

    Gong, Miao; Zhu, Wei; Fan, Yujie; Zhang, Huiwen; Su, Ying

    2016-05-01

    The supercritical water gasification of ten different types of dewatered sewage sludges was investigated to understand the relationship between sludge properties and gasification products. Experiments were performed in a high-pressure autoclave at 400°C for 60 min. Results showed that gasification of sewage sludge in supercritical water consists mainly of a gasification reaction, a carbonization reaction and a persistent organic pollutants synthesis reaction. Changes in the reactant C/H/O composition have significant effects on the key gasification products. Total gas production increased with increasing C/H2O of the reactant. The char/coke content increased with increasing C/H ratio of the reactant. A decrease in the C/O ratio of the reactant led to a reduction in polycyclic aromatic hydrocarbon formation. This means that we can adjust the reactant C/H/O composition by adding carbon-, hydrogen-, and oxygen-containing substances such as coal, algae and H2O2 to optimize hydrogen production and to inhibit an undesired by-product formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The influence hydrogen atom addition has on charge switching during motion of the metal atom in endohedral Ca@C60H4 isomers

    Science.gov (United States)

    Raggi, G.; Besley, E.; Stace, A. J.

    2016-01-01

    Density functional theory has been applied in a study of charge transfer between an endohedral calcium atom and the fullerene cage in Ca@C60H4 and [Ca@C60H4]+ isomers. Previous calculations on Ca@C60 have shown that the motion of calcium within a fullerene is accompanied by large changes in electron density on the carbon cage. Based on this observation, it has been proposed that a tethered endohedral fullerene might form the bases of a nanoswitch. Through the addition of hydrogen atoms to one hemisphere of the cage it is shown that, when compared with Ca@C60, asymmetric and significantly reduced energy barriers can be generated with respect to motion of the calcium atom. It is proposed that hydrogen atom addition to a fullerene might offer a route for creating a bi-stable nanoswitch that can be fine-tuned through the selection of an appropriate isomer and number of atoms attached to the cage of an endohedral fullerene. This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’. PMID:27501967

  9. Solvent fractionation of rambutan (Nephelium lappaceum L. kernel fat for production of non-hydrogenated solid fat: Influence of time and solvent type

    Directory of Open Access Journals (Sweden)

    Busakorn Mahisanunt

    2017-01-01

    Full Text Available The present study performed isothermal (25 °C solvent fractionation of rambutan (Nephelium lappaceum L. kernel fat (RKF to obtain the fat fraction that had melting properties comparable to a commercial hydrogenated solid fat. The effect of two fractionation parameters, holding time (12, 18 and 24 h and solvent types (acetone and ethanol, on the properties of fractionated fat were investigated. The results showed that a fractionation time increase caused an increased yield and decreased iodine value for the high melting or stearin fractions. The thermal behaviors and solid fat index (SFI of these stearin fractions were different from the original fat, especially for stearin from acetone fractionation. The major fatty acid in this stearin fraction was arachidic acid (C20:0 consisting of more than 90%. Overall, we demonstrated that acetone fractionation of RKF at 25 °C for 24 h is effective for producing a solid fat fraction, which has comparable crystallizing and melting properties to commercial hydrogenated fat. The fractionated rambutan fat obtained by this process may lead to its potential use in specific food products.

  10. Microsolvation of Mg²⁺, Ca²⁺: strong influence of formal charges in hydrogen bond networks.

    Science.gov (United States)

    Gonzalez, Juan David; Florez, Elizabeth; Romero, Jonathan; Reyes, Andrés; Restrepo, Albeiro

    2013-04-01

    A stochastic exploration of the quantum conformational spaces in the microsolvation of divalent cations with explicit consideration of up to six solvent molecules [Mg (H₂O)n)](2+), (n=3, 4, 5, 6) at the B3LYP, MP2, CCSD(T) levels is presented. We find several cases in which the formal charge in Mg²⁺ causes dissociation of water molecules in the first solvation shell, leaving a hydroxide ion available to interact with the central cation, the released proton being transferred to outer solvation shells in a Grotthus type mechanism; this particular finding sheds light on the capacity of Mg²⁺ to promote formation of hydroxide anions, a process necessary to regulate proton transfer in enzymes with exonuclease activity. Two distinct types of hydrogen bonds, scattered over a wide range of distances (1.35-2.15 Å) were identified. We find that in inner solvation shells, where hydrogen bond networks are severely disturbed, most of the interaction energies come from electrostatic and polarization+charge transfer, while in outer solvation shells the situation approximates that of pure water clusters.

  11. Hydrogen storage via polyhydride complexes

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, C.M. [Univ. of Hawaii, Honolulu, HI (United States)

    1996-10-01

    Polyhydride metal complexes are being developed for application to hydrogen storage. Complexes have been found which catalyze the reversible hydrogenation of unsaturated hydrocarbons. This catalytic reaction could be the basis for a low temperature, hydrogen storage system with a available hydrogen density greater than 7 weight percent. The P-C-P pincer complexes, RhH{sub 2}(C{sub 6}H{sub 3}-2,6-(CH{sub 2}PBu{sup t}{sub 2}){sub 2}) and IrH{sub 2}(C{sub 6}H{sub 3}-2,6-(CH{sub 2}PBu{sup t}{sub 2}){sub 2}) have unprecedented, long term stability at elevated temperatures. The novel iridium complex catalyzes the transfer dehydrogenation of cycloctane to cyclooctene at the rate of 716 turnovers/h which is 2 orders of magnitude greater than that found for previously reported catalytic systems which do not require the sacrificial hydrogenation of a large excess of hydrogen acceptor.

  12. Reduced climate sensitivity of carbon, oxygen and hydrogen stable isotope ratios in tree-ring cellulose of silver fir (Abies alba Mill.) influenced by background SO2 in Franconia (Germany, Central Europe).

    Science.gov (United States)

    Boettger, Tatjana; Haupt, Marika; Friedrich, Michael; Waterhouse, John S

    2014-02-01

    The climate sensitivity of carbon (δ(13)C), oxygen (δ(18)O) and hydrogen (δ(2)H) isotope signatures in tree-ring cellulose of Abies alba Mill. from a marginally industrialized area of Franconia (Germany) was analysed for the last 130 years. All isotopes preserve climatic signals up to c. 1950 AD. After 1950 we observe a clear reduction in climate sensitivity of δ(13)C and δ(2)H while δ(18)O - climate relations remain well pronounced. Nevertheless statistical tests implied that SO2 background emissions of West Germany had influenced isotope signatures long before 1950. The relationships between isotope values and concentrations of SO2, dust, O3 and NO2 at the regional level during the period 1979-2006 indicate that δ(13)C and δ(18)O were influenced primarily by SO2. The impact of SO2 on δ(2)H was negligible, but the observed reduction of climate sensitivity may be caused by synergic influences. The results have significant implications if isotope signatures from tree-rings from anthropogenic influenced regions are used to reconstruct past climate. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Scenarios of hydrogen production from wind power

    Energy Technology Data Exchange (ETDEWEB)

    Klaric, Mario

    2010-09-15

    Since almost total amount of hydrogen is currently being produced from natural gas, other ways of cleaner and 'more renewable' production should be made feasible in order to make benchmarks for total 'hydrogen economy'. Hydrogen production from wind power combined with electrolysis imposes as one possible framework for new economy development. In this paper various wind-to-hydrogen scenarios were calculated. Cash flows of asset based project financing were used as decision making tool. Most important parameters were identified and strategies for further research and development and resource allocation are suggested.

  14. Influence of Superparameterization and a Higher-Order Turbulence Closure on Rainfall Bias Over Amazonia in Community Atmosphere Model Version 5: How Parameterization Changes Rainfall

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai [Jackson School of Geosciences, University of Texas at Austin, Austin TX USA; Fu, Rong [Jackson School of Geosciences, University of Texas at Austin, Austin TX USA; Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles CA USA; Shaikh, Muhammad J. [Jackson School of Geosciences, University of Texas at Austin, Austin TX USA; Ghan, Steven [Pacific Northwest National Laboratory, Richland WA USA; Wang, Minghuai [Institute for Climate and Global Change Research and School of Atmospheric Sciences, Nanjing University, Nanjing China; Collaborative Innovation Center of Climate Change, Nanjing China; Leung, L. Ruby [Pacific Northwest National Laboratory, Richland WA USA; Dickinson, Robert E. [Jackson School of Geosciences, University of Texas at Austin, Austin TX USA; Marengo, Jose [Centro Nacional de Monitoramento e Alertas aos Desastres Naturais, São Jose dos Campos Brazil

    2017-09-21

    We evaluate the Community Atmosphere Model Version 5 (CAM5) with a higher-order turbulence closure scheme, named Cloud Layers Unified By Binomials (CLUBB), and a Multiscale Modeling Framework (MMF) with two different microphysics configurations to investigate their influences on rainfall simulations over Southern Amazonia. The two different microphysics configurations in MMF are the one-moment cloud microphysics without aerosol treatment (SAM1MOM) and two-moment cloud microphysics coupled with aerosol treatment (SAM2MOM). Results show that both MMF-SAM2MOM and CLUBB effectively reduce the low biases of rainfall, mainly during the wet season. The CLUBB reduces low biases of humidity in the lower troposphere with further reduced shallow clouds. The latter enables more surface solar flux, leading to stronger convection and more rainfall. MMF, especially MMF-SAM2MOM, unstablizes the atmosphere with more moisture and higher atmospheric temperatures in the atmospheric boundary layer, allowing the growth of more extreme convection and further generating more deep convection. MMF-SAM2MOM significantly increases rainfall in the afternoon, but it does not reduce the early bias of the diurnal rainfall peak; LUBB, on the other hand, delays the afternoon peak time and produces more precipitation in the early morning, due to more realistic gradual transition between shallow and deep convection. MMF appears to be able to realistically capture the observed increase of relative humidity prior to deep convection, especially with its two-moment configuration. In contrast, in CAM5 and CAM5 with CLUBB, occurrence of deep convection in these models appears to be a result of stronger heating rather than higher relative humidity.

  15. Field test of hydrogen in the natural gas grid

    Energy Technology Data Exchange (ETDEWEB)

    Iskov, H.

    2010-08-15

    In order to prepare for a future use of hydrogen as a fuel gas it became evident that very little information existed regarding the compatibility between long-term exposure and transportation of hydrogen in natural gas pipelines. A program was therefore set to study the transportation in a small-scale pilot grid at the research centre in Hoersholm, Denmark. The test program included steel pipes from the Danish gas transmission grid and polymer pipes from the Danish and Swedish gas distribution grid. The test of polymer pipes was devised so that samples of all test pipes were cut out of the grid each year and analysis performed on these pipe samples; in this way any form of influence on the integrity of the polyethylene pipe would be detected. The analytical program for polymer was devised in order to detect any influence on the additivation of the polyethylene as this has an influence on oxidative resistance, as well as checking already encountered possible degradation caused by extrusion of the material. Further tools as rheology and melt flow rate were used for detecting any structural changes on the material. On the mechanical property side the tensile strength and modulus were followed as well as the most important property for the pipe line, namely slow crack growth. The results of the polymer pipe tests show no degradations of any kind related to the continuous hydrogen exposure for more than 4 years. This is a strong indication of the compatibility to hydrogen of the tested polymer materials PE 80 and PE 100. The object of the steel pipe test was to see the effect on fatigue life of existing natural gas transmission lines with hydrogen replacing the natural gas. Full-scale dynamic tests were performed using randomly selected cut-out API 5L X70 pipe sections with a diameter of 20 inches and a wall thickness of 7 millimetres from the Danish natural gas transmission system. The pipe sections contained field girth weld made during the installation of the pipe

  16. Spatial distribution of atomic and ion hydrogen flux and its effect on hydrogen recycling in long duration confined and non-confined plasmas

    Directory of Open Access Journals (Sweden)

    A. Kuzmin

    2017-08-01

    Full Text Available In order to understand the atomic hydrogen distribution in different kinds of plasma and its influence on the recycling, two kinds of plasmas were used: non-confined annular electron cyclotron resonance (ECR and confined long duration plasmas. The permeation probes are used to measure directly the atomic hydrogen flux at several poloidal positions. The permeation through metals due to the ion and atom component of the hydrogen flux to the wall is indistinguishable. To estimate the contribution of the ions directly, Langmuir probes were used. The Гinc profile behind the plasma facing components (PFCs is almost constant, ∼2 ×1018 H/s/m2.

  17. A influência das perdas auditivas sensorioneurais na ordenação temporal The influence of sensoryneural hearing loss on temporal ordering

    Directory of Open Access Journals (Sweden)

    Giselle Goulart de Oliveira Matos

    2013-01-01

    examination, basic audiological testing and hearing process screening with the Dichotic Digit Test. After this process, the participants were allocated into three groups, namely: G1 (normal hearing for the averages of 0.5 / 1 / 2 and 3/4/6 KHz, G2 (mild hearing loss in at least one of the averages and G3 (moderate loss in at least one of the averages. The results were analyzed through comparison between normal hearing and the presence of hearing loss (G2 + G3 and among the three groups described. The normality index used was 70% of successes. For statistical analysis, the tests used were Nonparametric Mann-Whitney, Kruskal-Wallis ANOVA, "One-way" Analysis of Variance, student's t and chi-square. The determining criterion of significance adopted was level 5%. RESULTS: there was a significant presence of men with hearing loss in the group. The percentage of correct answers in the overall sample was 62.3%, revealing no statistically significant difference among groups. CONCLUSION: the temporal ordering ability evaluated by the Duration Pattern Test is not influenced by mild to moderate sensoryneural hearing loss.

  18. Towards a sustainable hydrogen economy: Hydrogen pathways and infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Mulder, Grietus; Lenaers, Guido [VITO, Boeretang 200, B-2400 Mol (Belgium); Hetland, Jens [SINTEF Energy Research, Kolbjorn Hejesvei 1A, N-7465 Trondheim (Norway)

    2007-07-15

    Results from the European HySociety project (2003-2005) are revealed in which political, societal and technical challenges for developing a European hydrogen economy have been addressed. The focus is placed on the assessments of hydrogen pathways and infrastructure. It will show that no chain can be selected as an obvious winner according to primary energy demand, emission and cost. In order to ensure that the pathway losses are compensated by the more efficient end-use of the H{sub 2} fuel, calculations based on well-to-tank losses and tank-to-wheel efficiencies are used. Furthermore, in order to look into the consequences of introducing hydrogen, a top-down scenario has been worked out. The message is that certainly the hydrogen distribution part for the transport application has to be improved to avoid loosing the emission gain that is obtainable, especially via carbon capture and storage of the CO{sub 2}. In order to quantify the market development a bottom-up approach has been established in particular for the transport sector. (author)

  19. A hydrogen ice cube

    NARCIS (Netherlands)

    Peters, C.J.; Schoonman, J.; Schrauwers, A.

    2004-01-01

    Hydrogen is considered to be a highly promising energy carrier. Nonetheless, before hydrogen can become the fuel of choice for the future a number of slight problems will have to be overcome. For example, how can hydrogen be safely stored? Motor vehicles running on hydrogen may be clean in concept

  20. Visualization of Hydrogen Diffusion in a Hydrogen-Enhanced Fatigue Crack Growth in Type 304 Stainless Steel

    Science.gov (United States)

    Matsunaga, Hisao; Noda, Hiroshi

    2011-09-01

    To study the influence of hydrogen on the fatigue strength of AISI type 304 metastable austenitic stainless steel, specimens were cathodically charged with hydrogen. Using tension-compression fatigue tests, the behavior of fatigue crack growth from a small drill hole in the hydrogen-charged specimen was compared with that of noncharged specimen. Hydrogen charging led to a marked increase in the crack growth rate. Typical characteristics of hydrogen effect were observed in the slip band morphology and fatigue striation. To elucidate the behavior of hydrogen diffusion microscopically in the fatigue process, the hydrogen emission from the specimens was visualized using the hydrogen microprint technique (HMT). In the hydrogen-charged specimen, hydrogen emissions were mainly observed in the vicinity of the fatigue crack. Comparison between the HMT image and the etched microstructure image revealed that the slip bands worked as a pathway for hydrogen to move preferentially. Hydrogen-charging resulted in a significant change in the phase transformation behavior in the fatigue process. In the noncharged specimen, a massive type α' martensite was observed in the vicinity of the fatigue crack. On the other hand, in the hydrogen-charged specimen, large amounts of ɛ martensite and a smaller amount of α' martensite were observed along the slip bands. The results indicated that solute hydrogen facilitated the ɛ martensitic transformation in the fatigue process. Comparison between the results of HMT and EBSD inferred that martensitic transformations as well as plastic deformation itself can enhance the mobility of hydrogen.

  1. Hydrogen generation from renewable resources

    Energy Technology Data Exchange (ETDEWEB)

    Loges, Bjoern

    2009-09-04

    In this thesis, the hydrogen generation by dehydrogenation of 2-propanol and formic acid as model substances for renewable resources have been studied, which is of importance for hydrogen storage. For the base-assisted dehydrogenation of 2-propanol, a ruthenium diamine catalyst system has been investigated. For the selective decomposition of formic acid to hydrogen and carbon dioxide, a system has been established containing ruthenium catalysts and formic acid amine adducts as substrates. The best catalyst activity and productivity have been achieved with in situ generated ruthenium phosphine catalysts, e.g. [RuCl{sub 2}(benzene)]{sub 2} / dppe (TOF = 900 h{sup -1}, TON = 260,000). The gas evolved has been directly used in fuel cells. Furthermore, the influence of irradiation with visible light has been described for the ruthenium phosphine catalysts. (orig.)

  2. Word Order

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2015-01-01

    The way constituents are ordered in a linguistic expression is determined by general principles and language specific rules. This article is mostly concerned with general ordering principles and the three main linguistic categories that are relevant for constituent order research: formal......, functional and semantic categories. The general principles appear to be motivated by cognitive considerations, which are deemed to facilitate language processing and which can all be regarded as manifestations of iconicity: non-arbitrary relations between the form and the content of a linguistic expression....... Three major iconic ordering principles are the principles of Domain Integrity, Scope, and Head Proximity....

  3. Storage of hydrogen on carbons; Stockage de l'hydrogene sur les carbones

    Energy Technology Data Exchange (ETDEWEB)

    Conard, J. [Centre National de la Recherche Scientifique, CNRS-CRMD, 45 - Orleans-la-Source (France)

    2000-07-01

    The storage of hydrogen on carbons, with densities above 10% hydrogen weight, can be used in the sector of transport. However, only the physical-sorption of this gas (which is almost perfect and boils at 20 K under atmospheric pressure) cannot explain this performance. A study of the possible sites for one hydrogen, which can take very different forms, is presented, in order to better understand the rational development of this storage mode which could reach about ten weight %. (O.M.)

  4. The role of hydrogen partial pressure on the annealing of copper substrates for graphene CVD synthesis

    Science.gov (United States)

    Ramos, Welyson T. S.; Cunha, Thiago H. R.; Barcelos, Ingrid D.; Miquita, Douglas R.; Ferrari, Gustavo A.; de Oliveira, Sergio; Seara, Luciana M.; Silva Neto, Eliel G.; Ferlauto, Andre S.; Lacerda, Rodrigo G.

    2016-04-01

    The influence of hydrogen utilized during the thermal treatment of copper substrates on the subsequent graphene growth is investigated. It is known that various parameters such as nature of the carbon precursor, temperature and pressure strongly affect the quality of the graphene grown by chemical vapor deposition. Another important parameter is the hydrogen partial pressure adjusted during the growth stage and in the pre-growth annealing of the substrate. In attempts to elucidate the role of hydrogen assisted thermal annealing on the copper substrate morphology and on the subsequent graphene growth, we subjected Cu foils to thermal annealing under H2 atmosphere at different pressures. The copper surface was characterized by scanning electronic microscopy (SEM) and atomic force microscopy whereas graphene films and grains were characterized by Raman spectroscopy and SEM. Our findings suggest that hydrogen not only affect the Cu surface but also diffuses into the substrate, being stored in the bulk material during the thermal treatment of the substrate. The release of hydrogen species in the subsequent stages of growth can result in damage to the graphene layer or induce the nucleation of additional layers depending on the growth and pre-growth conditions. Therefore, the use of hydrogen during the annealing of ‘low purity Cu foils’ should be carefully planned in order to obtain high quality graphene via LPCVD.

  5. Study of the hydrogen behavior in amorphous hydrogenated materials of type a - C:H and a - SiC:H facing fusion reactor plasma; Etude du comportament de l`hydrogene dans des materiaux amorphes hydrogenes de type a - C:H et a - SiC:H devant faire face au plasma des reacteurs a fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barbier, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire

    1997-04-10

    Plasma facing components of controlled fusion test devices (tokamaks) are submitted to several constraints (irradiation, high temperatures). The erosion (physical sputtering and chemical erosion) and the hydrogen recycling (retention and desorption) of these materials influence many plasma parameters and thus affect drastically the tokamak running. First, we will describe the different plasma-material interactions. It will be pointed out, how erosion and hydrogen recycling are strongly related to both chemical and physical properties of the material. In order to reduce these interactions, we have selected two amorphous hydrogenated materials (a-C:H and a-SiC:H), which are known for their good thermal and chemical qualities. Some samples have been then implanted with lithium ions at different fluences. Our materials have been then irradiated with deuterium ions at low energy. From our results, it is shown that both the lithium implantation and the use of an a - SiC:H substrate can be beneficial in enhancing the hydrogen retention. These results were completed with thermal desorption studies of these materials. It was evidenced that the hydrogen fixation was more efficient in a-SiC:H than in a-C:H substrate. Results in good agreement with those described above have been obtained by exposing a - C:H and a - SiC:H samples to the scrape off layer of the tokamak of Varennes (TdeV, Canada). A modelling of hydrogen diffusion under irradiation has been also proposed. (author) 176 refs.

  6. Maximizing hydrogen production and substrate consumption by Escherichia coli WDHL in cheese whey fermentation.

    Science.gov (United States)

    Rosales-Colunga, Luis Manuel; Alvarado-Cuevas, Zazil Donaxí; Razo-Flores, Elías; Rodríguez, Antonio De León

    2013-10-01

    Fermentative hydrogen production is strongly affected by pH. In order to maximize hydrogen production and substrate consumption in Escherichia coli ΔhycA, ΔlacI (WDHL) cheese whey fermentation, the influence of pH control at values of 5.5, 6, and 6.5 was studied in batch stirred-tank bioreactors. From the conditions evaluated, pH 6.5 was the best condition, at which the highest cumulative hydrogen production and yield (1.78 mol H2/mol lactose) were obtained. Moreover, at this pH, all carbohydrates from the cheese whey were consumed, and a mix of ethanol and organic acids, mainly lactate, were produced from glucose, whereas galactose yielded acetate, ethanol, and succinate. Operating the reactor at pH 5.5 resulted in the highest maximum specific production rate, but smaller hydrogen yield because only glucose was metabolized and galactose was accumulated. At pH 6, not all cheese whey carbohydrates were consumed, and it was not favorable for hydrogen production. Lactose consumption and growth kinetics were not affected by the pH. The results show the importance of controlling pH to maximize hydrogen production and substrate consumption using cheese whey as substrate.

  7. The effect of TTNT nanotubes on hydrogen sorption using MgH{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Brum, Mariana Coutinho; Jardim, Paula Mendes; Conceicao, Monique Osorio Talarico da; Santos, Dilson Silva dos, E-mail: monique@metalmat.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEMM/COPPEP/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2013-11-01

    Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH{sub 2} with the addition of TTNT (TiTanate nanotubes). The MgH{sub 2} -TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (%)) on the hydrogen capacity was evaluated. The milling of pure MgH{sub 2} was performed for 24 hours and afterwards the MgH{sub 2} -TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to evaluate the nanotube synthesis and show the particle morphology of the MgH{sub 2} -TTNT composite, respectively. The Differential Scanning Calorimetry (DSC) examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%). (author)

  8. A study on hydrogen-storage behaviors of nickel-loaded mesoporous MCM-41.

    Science.gov (United States)

    Park, Soo-Jin; Lee, Seul-Yi

    2010-06-01

    The objective of the present work was to investigate the possibility of improving the hydrogen-storage capacity of mesoporous MCM-41 containing nickel (Ni) oxides (Ni/MCM-41). The MCM-41 and Ni/MCM-41 were prepared using a hydrothermal process as a function of Ni content (2, 5, and 10 wt.% in the MCM-41). The surface functional groups of the Ni/MCM-41 were identified by Fourier transform infrared spectroscopy (FTIR). The structure and morphology of the Ni/MCM-41 were characterized by X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). XRD results showed a well-ordered hexagonal pore structure; FE-TEM also revealed, as a complementary technique, the structure and pore size. The textural properties of the Ni/MCM-41 were analyzed using N(2) adsorption isotherms at 77 K. The hydrogen-storage capacity of the Ni/MCM-41 was evaluated at 298 K/100 bar. It was found that the presence of Ni on mesoporous MCM-41 created hydrogen-favorable sites that enhanced the hydrogen-storage capacity by a spillover effect. Furthermore, it was concluded that the hydrogen-storage capacity was greatly influenced by the amount of nickel oxide, resulting in a chemical reaction between Ni/MCM-41 and hydrogen molecules. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

  9. The effect of TTNT nanotubes on hydrogen sorption using MgH2

    Directory of Open Access Journals (Sweden)

    Mariana Coutinho Brum

    2013-06-01

    Full Text Available Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH2 with the addition of TTNT (TiTanate NanoTubes. The MgH2-TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (% on the hydrogen capacity was evaluated. The milling of pure MgH2 was performed for 24 hours and afterwards the MgH2-TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM and Scanning Electron Microscopy (SEM were used to evaluate the nanotube synthesis and show the particle morphology of the MgH2-TTNT composite, respectively. The Differential Scanning Calorimetry (DSC examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%.

  10. Effect of vegetable oil oxidation on the hydrogenation reaction process

    OpenAIRE

    Kalantari, Faranak; Bahmaei, Manochehr; Ameri, Majid; Shoaei, Ehsan

    2010-01-01

    Hydrogenation has been carried out in a batch reactor with three different oxidized bleached oils in order to discover the effect of oxidation on the hydrogenation reaction process. Specifications of hydrogenated oils such as melting point, Iodine value, solid fat content and fatty acid composition of the oxidized oils were compared with their un-oxidized reference oils. Oxidized bleached sunflower oil was hydrogenated to target melting points (34, 39 and 42°C) at higher iodine values vs. its...

  11. Development of hydrogen storage systems using sodium alanate

    Energy Technology Data Exchange (ETDEWEB)

    Lozano Martinez, Gustavo Adolfo

    2010-12-06

    In this work, hydrogen storage systems based on sodium alanate were studied, modelled and optimised, using both experimental and theoretical approaches. The experimental approach covered investigations of the material from mg scale up to kg scale in demonstration test tanks, while the theoretical approach discussed modelling and simulation of the hydrogen sorption process in a hydride bed. Both approaches demonstrated the strong effect of heat transfer on the sorption behaviour of the hydride bed and led to feasible methods to improve and optimise the volumetric and gravimetric capacities of hydrogen storage systems. The applied approaches aimed at an optimal integration of sodium alanate material in practical hydrogen storage systems. First, it was experimentally shown that the size of the hydride bed influences the hydrogen sorption behaviour of the material. This is explained by the different temperature profiles that are developed inside the hydride bed during the sorptions. In addition, in a self-constructed cell it was possible to follow the hydrogen sorptions and the developed temperature profiles within the bed. Moreover, the effective thermal conductivity of the material was estimated in-situ in this cell, given very good agreement with reported values of ex-situ measurements. It was demonstrated that the effective thermal conductivity of the hydride bed can be enhanced by the addition of expanded graphite. This enhancement promotes lower temperature peaks during the sorptions due to faster heat conduction through the bed, which in addition allows faster heat transfer during sorption. Looking towards simulations and further evaluations, empirical kinetic models for both hydrogen absorption and desorption of doped sodium alanate were developed. Based on the results of the model, the optimal theoretical pressure-temperature conditions for hydrogen sorptions were determined. A new approach is proposed for the mass balance of the reactions when implementing

  12. The influence of antiobesity media content on intention to eat healthily and exercise: a test of the ordered protection motivation theory

    National Research Council Canada - National Science Library

    Ritland, Raeann; Rodriguez, Lulu

    2014-01-01

    This study extended the ordered protection motivation framework to determine whether exposure and attention to antiobesity media content increases people's appraisals of threat and their ability to cope...

  13. Influence of geometrical non-uniformities of LaNi5 metal hydride bed on its structure and heat and mass transfer at hydrogen absorption

    Science.gov (United States)

    Blinov, D. V.; Dunikov, D. O.; Kazakov, A. N.; Romanov, I. A.

    2017-11-01

    We perform cycling of a 500 g bed of La0.9Ce0.1Ni5 intermetallic compound in vertical and horizontal orientations with measurements of PCT isotherms, and further XRD and SEM investigation of bed structure. Significant decrease in equilibrium absorption pressure is observed in vertical orientation of the bed from 1.58 to 1.36 MPa at 333K, and from 2.68 to 2.51 MPa at 353K, accompanied by evident particle segregation by the bed height and densification at a bottom with formation of a robust agglomerate of small particles (mass transfer inside a vertical metal hydride reactor RSP-8 with 1 kg of La0.9Ce0.1Ni5 also show considerable non-uniformity of pressure inside the bed. If the reactor is charged from the top the hydrogen pressure at the bottom is lower on 0.2-0.3 MPa, which results in earlier occurrence of heat and mass transfer crisis.

  14. Influence of dietary partially hydrogenated fat high in trans fatty acids on lipid composition and function of intestinal brush border membrane in rats.

    Science.gov (United States)

    Ghafoorunissa, S A.I.

    2001-02-01

    The effect of dietary hydrogenated fat (Indian vanaspati) high in trans fatty acids (6 en%) on lipid composition, fluidity and function of rat intestinal brush border membrane was studied at 2 and 8 en% of linoleic acid. Three groups of weanling rats were fed rice-pulse based diet containing 10% fat over a ten week period: Group I (groundnut oil), Group II (vanaspati), Group III (vanaspati + safflower oil). The functionality of the brush border membrane was assessed by the activity of membrane bound enzymes and transport of D-glucose and L-leucine. The levels of total cholesterol and phospholipids were similar in all groups. The data on fatty acid composition of membrane phospholipids showed that, at 2 en% of linoleic acid in the diet, trans fatty acids lowered arachidonic acid and increased linoleic acid contents indicating altered polyunsaturated fatty acid metabolism. Alkaline phosphatase activity was increased while the activities of sucrase, gamma-glutamyl transpeptidase and transport of D-glucose and L-leucine were not altered by dietary trans fatty acids. However at higher intake of linoleic acid in the diet, trans fatty acids have no effect on polyunsaturated fatty acid composition and alkaline phosphatase activity of intestinal brush border membrane. These data suggest that feeding dietary fat high in trans fatty acids is associated with alteration in intestinal brush border membrane polyunsaturated fatty acid composition and alkaline phosphatase activity only when the dietary linoleic acid is low.

  15. Influence of the pH on molecular hydrogen primary yields in He{sup 2+} ion tracks in liquid water. A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Cobut, Vincent [Departement de Chimie, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville/Oise, 95031 Cergy-Pontoise Cedex (France)]. E-mail: vincent.cobut@chim.u-cergy.fr; Corbel, Catherine [CEA-Saclay, DSM/DRECAM/SCM/Laboratoire de Radiolyse, Bat. 546, Piece 5, 91191 Gif-sur-Yvette Cedex (France); Patau, Jean Paul [Faculte de Pharmacie, Universite Paul-Sabatier, 35 chemin des Maraichers, 31062 Toulouse Cedex 4 (France)

    2005-02-01

    Monte Carlo calculations are performed to investigate how the acidity of aqueous solutions at room temperature affects the molecular hydrogen (H{sub 2}) yield as a function of time in 20 MeV-He{sup 2+} ion track segments. For pH values varying from 1 to 13, the time dependence of the calculated yields is nearly independent of pH in the time range 10{sup -12}-10{sup -8} s and only weakly dependent in the time range 10{sup -8}-10{sup -6} s. To understand this behaviour, the kinetic mechanisms governing H{sub 2} formation are examined as a function of time. It is found that the main reactions responsible for the H{sub 2} yield as a function of time are strongly pH-dependent at low and high pH values. The pH-dependences of the reaction yields are however such that the variations in the yields compensate each other. This is why the time dependence of the H{sub 2} yield is only weakly pH-dependent.

  16. Hydrogen: the future energy carrier.

    Science.gov (United States)

    Züttel, Andreas; Remhof, Arndt; Borgschulte, Andreas; Friedrichs, Oliver

    2010-07-28

    Since the beginning of the twenty-first century the limitations of the fossil age with regard to the continuing growth of energy demand, the peaking mining rate of oil, the growing impact of CO2 emissions on the environment and the dependency of the economy in the industrialized world on the availability of fossil fuels became very obvious. A major change in the energy economy from fossil energy carriers to renewable energy fluxes is necessary. The main challenge is to efficiently convert renewable energy into electricity and the storage of electricity or the production of a synthetic fuel. Hydrogen is produced from water by electricity through an electrolyser. The storage of hydrogen in its molecular or atomic form is a materials challenge. Some hydrides are known to exhibit a hydrogen density comparable to oil; however, these hydrides require a sophisticated storage system. The system energy density is significantly smaller than the energy density of fossil fuels. An interesting alternative to the direct storage of hydrogen are synthetic hydrocarbons produced from hydrogen and CO2 extracted from the atmosphere. They are CO2 neutral and stored like fossil fuels. Conventional combustion engines and turbines can be used in order to convert the stored energy into work and heat.

  17. Improved hydrogen sorption kinetics in wet ball milled Mg hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Li

    2011-05-04

    In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively low temperatures. And it also shows good cycling sorption behavior, which decides on its industrial applicability. With three different catalysts MgH{sub 2} powder shows improved hydrogen sorption behavior as well as the cyclic sorption behavior. Among them, the Nb{sub 2}O{sub 5} catalyst is found to be the most effective one in this work. Compared to the wet ball milled MgH{sub 2} powder, the particle size and specific surface area of the MgH{sub 2} powder with catalysts are similar to the previous ones, while the grain size of the MgH{sub 2} with catalysts is much finer. In this case, two reasons for hydrogen sorption improvement are suggested: one is the reduction of the grain size. The other may be as pointed out in some literatures that formation of new oxidation could enhance the hydrogen sorption kinetics, which is also the reason why its hydrogen capacity is decreased compared to without catalysts. After further ball milling, the specific surface area of wet ball milled Mg

  18. Kinetic measurements and in situ Raman spectroscopy study of the formation of TBAF semi-hydrates with hydrogen and carbon dioxide

    NARCIS (Netherlands)

    Trueba, A.T.; Radović, I.R.; Zevenbergen, J.F.; Peters, C.J.; Kroon, M.C.

    2013-01-01

    The kinetics of formation of semi-clathrate hydrates of tetra n-butyl ammonium fluoride (TBAF) with hydrogen (H2) and carbon dioxide (CO2) were studied in order to elucidate their potential for H 2 storage as well as for CO2 sequestration. The influence of pressure, TBAF concentration (1.8 mol% and

  19. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  20. An Atomic X-ray Absorption Fine Structure Study of the Influence of Hydrogen Chemisorption and Support on the Electronic Structure of Supported Pt Particles

    NARCIS (Netherlands)

    Koningsberger, D.C.; Ramaker, D.E.; Dorssen, G.E. van; Mojet, B.L.

    2000-01-01

    The physical principles of atomic XAFS (AXAFS) are presented along with important details on how to isolate the AXAFS contribution from the experimental XAFS data. Intuitive illustrations are given showing how various interactions of the absorber atom with its neighbours influence the AXAFS

  1. Influences of Different Preparation Conditions on Catalytic Activity of Ag2O-Co3O4/γ-Al2O3 for Hydrogenation of Coal Pyrolysis

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

    Full Text Available A series of catalysts of Ag2O-Co3O4/γ-Al2O3 was prepared by equivalent volume impregnation method. The effects of the metal loading, calcination time, and calcination temperatures of Ag and Co, respectively, on the catalytic activity were investigated. The optimum preparing condition of Ag2O-Co3O4/γ-Al2O3 was decided, and then the influence of different preparation conditions on catalytic activity of Ag2O-Co3O4/γ-Al2O3 was analyzed. The results showed the following: (1 at the same preparation condition, when silver loading was 8%, the Ag2O-Co3O4/γ-Al2O3 showed higher catalyst activity, (2 the catalyst activity had obviously improved when the cobalt loading was 8%, while it was weaker at loadings 5% and 10%, (3 the catalyst activity was influenced by different calcination temperatures of silver, but the influences were not marked, (4 the catalyst activity can be influenced by calcination time of silver, (5 different calcination times of cobalt can also influence the catalyst activity of Ag2O-Co3O4/γ-Al2O3, and (6 the best preparation conditions of the Ag2O-Co3O4/γ-Al2O3 were silver loading of 8%, calcination temperature of silver of 450°C, and calcinations time of silver of 4 h, while at the same time the cobalt loading was 8%, the calcination temperature of cobalt was 450°C, and calcination time of cobalt was 4 h.

  2. Hydrogen nanobubble at normal hydrogen electrode

    Science.gov (United States)

    Nakabayashi, S.; Shinozaki, R.; Senda, Y.; Yoshikawa, H. Y.

    2013-05-01

    Electrochemically formed hydrogen nanobubbles at a platinum rotating disk electrode (RDE) were detected by re-oxidation charge. The dissolution time course of the hydrogen nanobubbles was measured by AFM tapping topography under open-circuit conditions at stationary platinum and gold single-crystal electrodes. The bubble dissolution at platinum was much faster than that at gold because two types of diffusion, bulk and surface diffusion, proceeded at the platinum surface, whereas surface diffusion was prohibited at the gold electrode. These findings indicated that the electrochemical reaction of normal hydrogen electrode partly proceeded heterogeneously on the three-phase boundary around the hydrogen nanobubble.

  3. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Kreutz, T.G.; Steinbugler, M. [Princeton Univ., NJ (United States)] [and others

    1996-10-01

    In this report the authors describe results from technical and economic assessments carried out during the past year with support from the USDOE Hydrogen R&D Program. (1) Assessment of technologies for small scale production of hydrogen from natural gas. Because of the cost and logistics of transporting and storing hydrogen, it may be preferable to produce hydrogen at the point of use from more readily available energy carriers such as natural gas or electricity. In this task the authors assess near term technologies for producing hydrogen from natural gas at small scale including steam reforming, partial oxidation and autothermal reforming. (2) Case study of developing a hydrogen vehicle refueling infrastructure in Southern California. Many analysts suggest that the first widespread use of hydrogen energy is likely to be in zero emission vehicles in Southern California. Several hundred thousand zero emission automobiles are projected for the Los Angeles Basin alone by 2010, if mandated levels are implemented. Assuming that hydrogen vehicles capture a significant fraction of this market, a large demand for hydrogen fuel could evolve over the next few decades. Refueling a large number of hydrogen vehicles poses significant challenges. In this task the authors assess near term options for producing and delivering gaseous hydrogen transportation fuel to users in Southern California including: (1) hydrogen produced from natural gas in a large, centralized steam reforming plant, and delivered to refueling stations via liquid hydrogen truck or small scale hydrogen gas pipeline, (2) hydrogen produced at the refueling station via small scale steam reforming of natural gas, (3) hydrogen produced via small scale electrolysis at the refueling station, and (4) hydrogen from low cost chemical industry sources (e.g. excess capacity in refineries which have recently upgraded their hydrogen production capacity, etc.).

  4. Changes in Hydrogen Content During Steelmaking

    Directory of Open Access Journals (Sweden)

    Vrbek K.

    2015-04-01

    Full Text Available Štore Steel produces steel grades for spring, forging and engineering industry applications. Steelmaking technology consists of scrap melting in Electric Arc Furnace (EAF, secondary metallurgy in Ladle Furnace (LF and continuous casting of billets (CC. Hydrogen content during steelmaking of various steel grades and steelmaking technologies was measured. Samples of steel melt from EAF, LF and CC were collected and investigated. Sampling from Electric Arc Furnace and Ladle Furnace was carried out using vacuum pin tubes. Regular measurements of hydrogen content in steel melt were made using Hydris device. Hydrogen content results measured in tundish by Hydris device were compared with results from pin tube samples. Based on the measurement results it was established that hydrogen content during steelmaking increases. The highest values were determined in tundish during casting. Factors that influence the hydrogen content in liquid steel the most were steelmaking technology and alloying elements.

  5. Hydrogen in semiconductors

    CERN Document Server

    Pankove, Jacques I

    1991-01-01

    Hydrogen plays an important role in silicon technology, having a profound effect on a wide range of properties. Thus, the study of hydrogen in semiconductors has received much attention from an interdisciplinary assortment of researchers. This sixteen-chapter volume provides a comprehensive review of the field, including a discussion of hydrogenation methods, the use of hydrogen to passivate defects, the use of hydrogen to neutralize deep levels, shallow acceptors and shallow donors in silicon, vibrational spectroscopy, and hydrogen-induced defects in silicon. In addition to this detailed cove

  6. The Influence of Antiobesity Media Content on Intention to Eat Healthily and Exercise: A Test of the Ordered Protection Motivation Theory

    National Research Council Canada - National Science Library

    Ritland, Raeann; Rodriguez, Lulu

    2014-01-01

      This study extended the ordered protection motivation framework to determine whether exposure and attention to antiobesity media content increases people's appraisals of threat and their ability to cope...

  7. Hydrogen bio-production through anaerobic microorganism fermentation using kitchen wastes as substrate.

    Science.gov (United States)

    Shi, Yue; Zhao, Xiu-Tao; Cao, Peng; Hu, Yinyin; Zhang, Liang; Jia, Yan; Lu, Zeqi

    2009-09-01

    In order to treat the kitchen wastes and produce hydrogen, anaerobic fermentation technology was used in this experiment. The results showed that the fermentation type changed from mixed acid fermentation to ethanol fermentation in a continuous stirred tank reactor (CSTR) 22 days after start-up. The maximum efficiency of hydrogen bio-production in the CSTR was 4.77 LH(2)/(L reactor d) under the following conditions: organic loading rate (OLR) of 32-50 kg COD/(m(3) d), oxidation reduction potential (ORP) of -450 to -400 mV, influent pH value of 5.0-6.0, effluent pH value of 4.0-4.5, influent alkalinity of 300-600 mg/l, temperature of 35 +/- 1 degrees C and hydraulic retention time (HRT) of 7 h. An artificial neural network (ANN) model was established, and each parameter influencing the performance of the reactor was compared using the method of partitioning connection weights (PCW). The results showed that OLR, pH, ORP and alkalinity could influence the fermentation characteristics and hydrogen yield of the anaerobic activated sludge; with an influence hierarchy: OLR > pH values > ORP > alkalinity. An economic analysis showed that the cost of producing hydrogen in this experiment was less than the cost of electrolysis of water.

  8. Nanostructures from hydrogen implantation of metals.

    Energy Technology Data Exchange (ETDEWEB)

    McWatters, Bruce Ray (Sandia National Laboratories, Albuquerque, NM); Causey, Rion A.; DePuit, Ryan J.; Yang, Nancy Y. C.; Ong, Markus D.

    2009-09-01

    This study investigates a pathway to nanoporous structures created by hydrogen implantation in aluminum. Previous experiments for fusion applications have indicated that hydrogen and helium ion implantations are capable of producing bicontinuous nanoporous structures in a variety of metals. This study focuses specifically on hydrogen and helium implantations of aluminum, including complementary experimental results and computational modeling of this system. Experimental results show the evolution of the surface morphology as the hydrogen ion fluence increases from 10{sup 17} cm{sup -2} to 10{sup 18} cm{sup -2}. Implantations of helium at a fluence of 10{sup 18} cm{sup -2} produce porosity on the order of 10 nm. Computational modeling demonstrates the formation of alanes, their desorption, and the resulting etching of aluminum surfaces that likely drives the nanostructures that form in the presence of hydrogen.

  9. Storage, transmission and distribution of hydrogen

    Science.gov (United States)

    Kelley, J. H.; Hagler, R., Jr.

    1979-01-01

    Current practices and future requirements for the storage, transmission and distribution of hydrogen are reviewed in order to identify inadequacies to be corrected before hydrogen can achieve its full potential as a substitute for fossil fuels. Consideration is given to the storage of hydrogen in underground solution-mined salt caverns, portable high-pressure containers and dewars, pressure vessels and aquifers and as metal hydrides, hydrogen transmission in evacuated double-walled insulated containers and by pipeline, and distribution by truck and internal distribution networks. Areas for the improvement of these techniques are indicated, and these technological deficiencies, including materials development, low-cost storage and transmission methods, low-cost, long-life metal hydrides and novel methods for hydrogen storage, are presented as challenges for research and development.

  10. Metallic Hydrogen: The Most Powerful Rocket Fuel Yet To Exist

    OpenAIRE

    Silvera, Isaac F.; Cole, John W.

    2010-01-01

    Wigner and Huntington first predicted that pressures of order 25 GPa were required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator. We discuss the applications of metast...

  11. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-06-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  12. Use of reversible hydrides for hydrogen storage

    Science.gov (United States)

    Darriet, B.; Pezat, M.; Hagenmuller, P.

    1980-01-01

    The addition of metals or alloys whose hydrides have a high dissociation pressure allows a considerable increase in the hydrogenation rate of magnesium. The influence of temperature and hydrogen pressure on the reaction rate were studied. Results concerning the hydriding of magnesium rich alloys such as Mg2Ca, La2Mg17 and CeMg12 are presented. The hydriding mechanism of La2Mg17 and CeMg12 alloys is given.

  13. Handbook of hydrogen energy

    CERN Document Server

    Sherif, SA; Stefanakos, EK; Steinfeld, Aldo

    2014-01-01

    ""This book provides an excellent overview of the hydrogen economy and a thorough and comprehensive presentation of hydrogen production and storage methods.""-Scott E. Grasman, Rochester Institute of Technology, New York, USA

  14. Center for Hydrogen Storage.

    Science.gov (United States)

    2013-06-01

    The main goals of this project were to (1) Establish a Center for Hydrogen Storage Research at Delaware State University for the preparation and characterization of selected complex metal hydrides and the determination their suitability for hydrogen ...

  15. Hydrogen production by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Chaudhuri Surabhi

    2005-12-01

    Full Text Available Abstract The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical, Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source.

  16. Hydrogen transport membranes

    Science.gov (United States)

    Mundschau, Michael V.

    2005-05-31

    Composite hydrogen transport membranes, which are used for extraction of hydrogen from gas mixtures are provided. Methods are described for supporting metals and metal alloys which have high hydrogen permeability, but which are either too thin to be self supporting, too weak to resist differential pressures across the membrane, or which become embrittled by hydrogen. Support materials are chosen to be lattice matched to the metals and metal alloys. Preferred metals with high permeability for hydrogen include vanadium, niobium, tantalum, zirconium, palladium, and alloys thereof. Hydrogen-permeable membranes include those in which the pores of a porous support matrix are blocked by hydrogen-permeable metals and metal alloys, those in which the pores of a porous metal matrix are blocked with materials which make the membrane impervious to gases other than hydrogen, and cermets fabricated by sintering powders of metals with powders of lattice-matched ceramic.

  17. Microstructured reactors for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Aartun, Ingrid

    2005-07-01

    Small scale hydrogen production by partial oxidation (POX) and oxidative steam reforming (OSR) have been studied over Rh-impregnated microchannel Fecralloy reactors and alumina foams. Trying to establish whether metallic microchannel reactors have special advantages for hydrogen production via catalytic POX or OSR with respect to activity, selectivity and stability was of special interest. The microchannel Fecralloy reactors were oxidised at 1000 deg C to form a {alpha}-Al2O3 layer in the channels in order to enhance the surface area prior to impregnation. Kr-BET measurements showed that the specific surface area after oxidation was approximately 10 times higher than the calculated geometric surface area. Approximately 1 mg Rh was deposited in the channels by impregnation with an aqueous solution of RhCl3. Annular pieces (15 mm o.d.,4 mm i.d., 14 mm length) of extruded {alpha}-Al2O3 foams were impregnated with aqueous solutions of Rh(NO3)3 to obtain 0.01, 0.05 and 0.1 wt.% loadings, as predicted by solution uptake. ICP-AES analyses showed that the actual Rh loadings probably were higher, 0.025, 0.077 and 0.169 wt.% respectively. One of the microchannel Fecralloy reactors and all Al2O3 foams were equipped with a channel to allow for temperature measurement inside the catalytic system. Temperature profiles obtained along the reactor axes show that the metallic microchannel reactor is able to minimize temperature gradients as compared to the alumina foams. At sufficiently high furnace temperature, the gas phase in front of the Rh/Al2O3/Frecralloy microchannel reactor and the 0.025 wt.% Rh/Al2O3 foams ignites. Gas phase ignition leads to lower syngas selectivity and higher selectivity to total oxidation products and hydrocarbon by-products. Before ignition of the gas phase the hydrogen selectivity is increased in OSR as compared to POX, the main contribution being the water-gas shift reaction. After gas phase ignition, increased formation of hydrocarbon by

  18. Solar hydrogen generator

    Science.gov (United States)

    Sebacher, D. I.; Sabol, A. P. (Inventor)

    1977-01-01

    An apparatus, using solar energy to manufacture hydrogen by dissociating water molecules into hydrogen and oxygen molecules is described. Solar energy is concentrated on a globe containing water thereby heating the water to its dissociation temperature. The globe is pervious to hydrogen molecules permitting them to pass through the globe while being essentially impervious to oxygen molecules. The hydrogen molecules are collected after passing through the globe and the oxygen molecules are removed from the globe.

  19. Hydrogen Technologies Safety Guide

    Energy Technology Data Exchange (ETDEWEB)

    Rivkin, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Burgess, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Buttner, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-01-01

    The purpose of this guide is to provide basic background information on hydrogen technologies. It is intended to provide project developers, code officials, and other interested parties the background information to be able to put hydrogen safety in context. For example, code officials reviewing permit applications for hydrogen projects will get an understanding of the industrial history of hydrogen, basic safety concerns, and safety requirements.

  20. The influence of cation ordering, oxygen vacancy distribution and proton siting on observed properties in ceramic electrolytes: the case of scandium substituted barium titanate.

    Science.gov (United States)

    Torino, Nico; Henry, Paul F; Knee, Christopher S; Bjørheim, Tor Svendsen; Rahman, Seikh M H; Suard, Emma; Giacobbe, Carlotta; Eriksson, Sten G

    2017-07-04

    The origin of the 2-order of magnitude difference in the proton conductivity of the hydrated forms of hexagonal and cubic oxygen deficient BaScxTi1-xO3-δ (x = 0.2 and x = 0.7) was probed using a combination of neutron diffraction and density functional theory techniques to support published X-ray diffraction, conductivity, thermogravimetric and differential scanning calorimetry studies. Cation ordering is found in the 6H structure type (space group P63/mmc) adopted by BaSc0.2Ti0.8O3-δ with scandium preferentially substituting in the vertex sharing octahedra (2a crystallographic site) and avoiding the face-sharing octahedra (4f site). This is coupled with oxygen vacancy ordering in the central plane of the face-sharing octahedra (O1 site). In BaSc0.7Ti0.3O3-δ a simple cubic perovskite (space group Pm3[combining macron]m) best represents the average structure from Rietveld analysis with no evidence of either cation ordering or oxygen vacancy ordering. Significant diffuse scattering is observed, indicative of local order. Hydration in both cases leads to complete filling of the available oxygen vacancies and permits definition of the proton sites. We suggest that the more localised nature of the proton sites in the 6H structure is responsible for the significantly lower proton conduction observed in the literature. Within the 6H structure type final model, proton diffusion requires a 3-step process via higher energy proton sites that are unoccupied at room temperature and is also likely to be anisotropic whereas the highly disordered cubic perovskite proton position allows 3-dimensional diffusion by well-described modes. Finally, we propose how this knowledge can be used to further materials design for ceramic electrolytes for proton conducting fuel cells.

  1. Characterization of solid hydrogen targets

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, M.C. [British Columbia Univ., Vancouver, BC (Canada); Bailey, J.M.; Mulhauser, F. [Chester Technology (United Kingdom); Beer, G.A.; Douglas, J.L.; Knowles, P.E.; Maier, M.; Mason, G.R.; Olin, A.; Porcelli, T.A. [Victoria Univ., BC (Canada); Beveridge, J.L.; Marshall, G.M. [British Columbia Univ., Vancouver, BC (Canada). TRIUMF Facility; Huber, T.M. [Gustavus Adolphus Coll., St. Peter, MN (United States); Jacot-Guillarmod, R. [Fribourg Univ. (Switzerland); Kammel, P. [Lawrence Berkeley Lab., CA (United States); Kim, S.K. [Jeonbuk National Univ., Jeonju City (Korea, Republic of); Kunselman, A.R. [Wyoming Univ., Laramie, WY (United States); Martoff, C.J. [Temple Univ., Philadelphia, PA (United States); Petitjean, C. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Zmeskal, J. [Oesterreichische Akademie der Wissenschaften, Vienna (Austria)

    1996-10-01

    In experiments using the TRIUMF solid hydrogen target system, the knowledge of the target thickness and uniformity is often essential in order to extract physical parameters from the data. We have characterized the thickness and uniformity of frozen targets using the energy loss of alpha particles. An accuracy of {approx}5% was achieved, a limit imposed by the uncertainty in the stopping powers. The details of the method are described, and the thickness calibration of the target is presented. (orig.). 11 refs.

  2. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

    Vigeholm, B.; Kjøller, John; Larsen, Bent

    1980-01-01

    The reaction of hydrogen with commercially pure magnesium powder (above 99.7%) was investigated in the temperature range 250–400 °C. Hydrogen is readily sorbed above the dissociation pressure. During the initial exposure the magnesium powder sorbs hydrogen slowly below 400 °C but during the second...

  3. Biological hydrogen photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Y. [Univ. of Miami, FL (United States)

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  4. Aperiodic order

    CERN Document Server

    Grimm, Uwe

    2017-01-01

    Quasicrystals are non-periodic solids that were discovered in 1982 by Dan Shechtman, Nobel Prize Laureate in Chemistry 2011. The mathematics that underlies this discovery or that proceeded from it, known as the theory of Aperiodic Order, is the subject of this comprehensive multi-volume series. This second volume begins to develop the theory in more depth. A collection of leading experts, among them Robert V. Moody, cover various aspects of crystallography, generalising appropriately from the classical case to the setting of aperiodically ordered structures. A strong focus is placed upon almost periodicity, a central concept of crystallography that captures the coherent repetition of local motifs or patterns, and its close links to Fourier analysis. The book opens with a foreword by Jeffrey C. Lagarias on the wider mathematical perspective and closes with an epilogue on the emergence of quasicrystals, written by Peter Kramer, one of the founders of the field.

  5. The Influence of Prosodic Input in the Second Language Classroom: Does It Stimulate Child Acquisition of Word Order and Function Words?

    Science.gov (United States)

    Campfield, Dorota E.; Murphy, Victoria A.

    2017-01-01

    This paper reports on an intervention study with young Polish beginners (mean age: 8 years, 3 months) learning English at school. It seeks to identify whether exposure to rhythmic input improves knowledge of word order and function words. The "prosodic bootstrapping hypothesis", relevant in developmental psycholinguistics, provided the…

  6. Neutron diffraction studies of Zr-containing intermetallic hydrides with ordered hydrogen sublattice. V. Orthorhombic Zr{sub 3}CoD{sub 6.9} with filled Re{sub 3}B-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Riabov, A.B.; Yartys, V.A. [Nat. Acad. of Sci., Lviv (Ukraine). Metal Hydrides Dept.; Fjellvaag, H.; Hauback, B.C.; Soerby, M.H. [Institute for Energy Technology, P.O. Box 40, Kjeller (Norway)

    2000-01-10

    For pt.IV see ibid., vol.290, p.157-163, 1999. Zr{sub 3}CoD{sub 6.9} deuteride (space group Cmcm; a=3.5959(1); b=10.9734(3); c=9.5961(3) A) has been studied by high resolution powder X-ray and neutron diffraction. Rietveld profile refinements showed that it is isostructural to Zr{sub 3}FeD{sub 6.7} with a filled Re{sub 3}B-type structure. D atoms occupy four types of interstitial positions. Deuterium sublattice is completely ordered and can be described as a spatial stacking of deformed cubes ZrD{sub 8} and deformed cubes with an extra ninth vertex ZrD{sub 9}. The shortest interatomic distances are: Zr-D=2.044(5); Co-D=1.727(8); D-D=2.025(6) A. (orig.)

  7. Influence of hydrogenated oil as cocoa butter replacers in the development of sugar-free compound chocolates: Use of inulin as stabilizing agent.

    Science.gov (United States)

    Rodriguez Furlán, Laura T; Baracco, Yanina; Lecot, Javier; Zaritzky, Noemi; Campderrós, Mercedes E

    2017-02-15

    The effect of the addition of inulin as a surfactant or stability agent on white compound chocolate sweetened with sucralose and Stevia was studied. Samples were stored at 7, 15 and 30°C during 100days and the influence of inulin on rheological properties, sensorial attributes, shelf-life, physical properties such as melting, crystallization and blooming were analyzed. The shelf-life of the compound chocolate with the incorporation of inulin was higher than the control sample without replacement. Compound chocolate with inulin at 10%w/w showed a dense matrix structure, reducing the size and number of fat crystals formed during storage; furthermore they presented higher values of brightness and WI. This chocolate also showed less fracturability and improved thermal properties. DSC studies revealed increased values of onset and peak temperatures and enthalpy of melting of the polymorphic form V, at higher storage temperatures, achieving greater stability against degradation processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Hydrogen separation process

    Science.gov (United States)

    Mundschau, Michael [Longmont, CO; Xie, Xiaobing [Foster City, CA; Evenson, IV, Carl; Grimmer, Paul [Longmont, CO; Wright, Harold [Longmont, CO

    2011-05-24

    A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen separation membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen separation membrane system wherein the hydrogen separation membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen separation membrane system comprising selecting a hydrogen separation membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen separation membrane system to a porous support.

  9. $\\Delta(1232)$-Resonance in the Hydrogen Spectrum

    OpenAIRE

    Hagelstein, Franziska

    2018-01-01

    The electromagnetic excitation of the $\\Delta(1232)$-resonance plays an appreciable role in the Lamb shift and hyperfine structure of muonic and electronic hydrogen. Its effect appears at the subleading order $\\mathcal{O}(\\alpha^5)$, together with other proton-polarizability contributions from forward two-photon exchange. We use the large-$N_c$ relations for the nucleon-to-delta transition form factors to compute the effect of the $\\Delta(1232)$ in the hydrogen spectrum. We pay particular att...

  10. On the ground state of metallic hydrogen

    Science.gov (United States)

    Chakravarty, S.; Ashcroft, N. W.

    1978-01-01

    A proposed liquid ground state of metallic hydrogen at zero temperature is explored and a variational upper bound to the ground state energy is calculated. The possibility that the metallic hydrogen is a liquid around the metastable point (rs = 1.64) cannot be ruled out. This conclusion crucially hinges on the contribution to the energy arising from the third order in the electron-proton interaction which is shown here to be more significant in the liquid phase than in crystals.

  11. Polymers for hydrogen infrastructure and vehicle fuel systems :

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Rachel Reina; Simmons, Kevin L.; San Marchi, Christopher W.

    2013-10-01

    This document addresses polymer materials for use in hydrogen service. Section 1 summarizes the applications of polymers in hydrogen infrastructure and vehicle fuel systems and identifies polymers used in these applications. Section 2 reviews the properties of polymer materials exposed to hydrogen and/or high-pressure environments, using information obtained from published, peer-reviewed literature. The effect of high pressure on physical and mechanical properties of polymers is emphasized in this section along with a summary of hydrogen transport through polymers. Section 3 identifies areas in which fuller characterization is needed in order to assess material suitability for hydrogen service.

  12. Possibilities of Using Hydrogen as Motor Vehicle Fuel

    Directory of Open Access Journals (Sweden)

    Zdravko Bukljaš

    2005-03-01

    Full Text Available Hydrogen is the fuel of the future, since it is the element ofwater (H20 whichsun·ounds us and the resources of which areunlimited. First water is divided into hydrogen and oxygen. Thepaper presents the laboratory and industrial methods of obtain·ing hydrogen, types of fuel cells for various purposes, hydrogen-propelled motor vehicles, as well as advantages and drawbacksof hydrogen used as fuel under the conditions that haveto be met in order to use it as propulsion energy for motor vehicles.

  13. Safe venting of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, W.F.; Dewart, J.M.; Edeskuty, F.J.

    1990-01-01

    The disposal of hydrogen is often required in the operation of an experimental facility that contains hydrogen. Whether the vented hydrogen can be discharged to the atmosphere safely depends upon a number of factors such as the flow rate and atmospheric conditions. Calculations have been made that predict the distance a combustible mixture can extend from the point of release under some specified atmospheric conditions. Also the quantity of hydrogen in the combustible cloud is estimated. These results can be helpful in deciding of the hydrogen can be released directly to the atmosphere, or if it must be intentionally ignited. 15 refs., 5 figs., 2 tabs.

  14. Significant change of local atomic configurations at surface of reduced activation Eurofer steels induced by hydrogenation treatments

    Energy Technology Data Exchange (ETDEWEB)

    Greculeasa, S.G.; Palade, P.; Schinteie, G. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Kuncser, A.; Stanciu, A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); University of Bucharest, Faculty of Physics, 77125, Bucharest-Magurele (Romania); Lungu, G.A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Porosnicu, C.; Lungu, C.P. [National Institute for Laser, Plasma and Radiation Physics, 77125, Bucharest-Magurele (Romania); Kuncser, V., E-mail: kuncser@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania)

    2017-04-30

    Highlights: • Engineering of Eurofer slab properties by hydrogenation treatments. • Hydrogenation modifies significantly the local atomic configurations at the surface. • Hydrogenation increases the expulsion of the Cr atoms toward the very surface. • Approaching binomial atomic distribution by hydrogenation in the next surface 100 nm. - Abstract: Reduced-activation steels such as Eurofer alloys are candidates for supporting plasma facing components in tokamak-like nuclear fusion reactors. In order to investigate the impact of hydrogen/deuterium insertion in their crystalline lattice, annealing treatments in hydrogen atmosphere have been applied on Eurofer slabs. The resulting samples have been analyzed with respect to local structure and atomic configuration both before and after successive annealing treatments, by X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and conversion electron Mössbauer spectroscopy (CEMS). The corroborated data point out for a bcc type structure of the non-hydrogenated alloy, with an average alloy composition approaching Fe{sub 0.9}Cr{sub 0.1} along a depth of about 100 nm. EDS elemental maps do not indicate surface inhomogeneities in concentration whereas the Mössbauer spectra prove significant deviations from a homogeneous alloying. The hydrogenation increases the expulsion of the Cr atoms toward the surface layer and decreases their oxidation, with considerable influence on the surface properties of the steel. The hydrogenation treatment is therefore proposed as a potential alternative for a convenient engineering of the surface of different Fe-Cr based alloys.

  15. Hydrogen storage in graphite nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Park, C.; Tan, C.D.; Hidalgo, R.; Baker, R.T.K.; Rodriguez, N.M. [Northeastern Univ., Boston, MA (United States). Chemistry Dept.

    1998-08-01

    Graphite nanofibers (GNF) are a type of material that is produced by the decomposition of carbon containing gases over metal catalyst particles at temperatures around 600 C. These molecularly engineered structures consist of graphene sheets perfectly arranged in a parallel, perpendicular or at angle orientation with respect to the fiber axis. The most important feature of the material is that only edges are exposed. Such an arrangement imparts the material with unique properties for gas adsorption because the evenly separated layers constitute the most ordered set of nanopores that can accommodate an adsorbate in the most efficient manner. In addition, the non-rigid pore walls can also expand so as to accommodate hydrogen in a multilayer conformation. Of the many varieties of structures that can be produced the authors have discovered that when gram quantities of a selected number of GNF are exposed to hydrogen at pressures of {approximately} 2,000 psi, they are capable of adsorbing and storing up to 40 wt% of hydrogen. It is believed that a strong interaction is established between hydrogen and the delocalized p-electrons present in the graphite layers and therefore a new type of chemistry is occurring within these confined structures.

  16. The influence of atomic order on the magnetic and structural properties of the ferromagnetic shape memory compound Ni sub 2 MnGa

    CERN Document Server

    Kreissl, M; Stephens, T; Ziebeck, K R A

    2003-01-01

    The effect of atomic order on the martensitic phase transition and magnetic properties of stoichiometric Ni sub 2 MnGa has been investigated in a sample quenched from 1000 deg C. Magnetization, resistivity and x-ray diffraction measurements indicate that the structural phase transition occurs at approx 103 K, substantially lower than the value reported for samples quenched from 800 deg C and ordered in the Heusler L2 sub 1 structure. A small reduction in the ferromagnetic moment was also observed, although the Curie temperature remained largely unaffected. The electronic Sommerfeld coefficient obtained from heat capacity measurements is enhanced but smaller than that observed for the 800 deg C quenched sample. The results are consistent with band structure calculations and the electronic changes brought about by atomic disorder.

  17. Stretching and Exploiting Thresholds for High-Order War: How Russia, China, and Iran are Eroding American Influence Using Time-Tested Measures Short of War

    Science.gov (United States)

    2016-01-01

    representative of standard—and long- standing—practices in international behavior.6 The bilateral, nuclear- era Cold War theories of military escalation that...4 Stretching and Exploiting Thresholds for High-Order War of-war actions that Russian president Vladimir Putin has been willing to take in Crimea...the realist precept of international anarchy. Various schools of realism describe this differently, but, at its core, realism views interstate

  18. Hydrogen energy for beginners

    CERN Document Server

    2013-01-01

    This book highlights the outstanding role of hydrogen in energy processes, where it is the most functional element due to its unique peculiarities that are highlighted and emphasized in the book. The first half of the book covers the great natural hydrogen processes in biology, chemistry, and physics, showing that hydrogen is a trend that can unite all natural sciences. The second half of the book is devoted to the technological hydrogen processes that are under research and development with the aim to create the infrastructure for hydrogen energetics. The book describes the main features of hydrogen that make it inalienable player in processes such as fusion, photosynthesis, and metabolism. It also covers the methods of hydrogen production and storage, highlighting at the same time the exclusive importance of nanotechnologies in those processes.

  19. Cyclooctanaminium hydrogen succinate monohydrate

    Directory of Open Access Journals (Sweden)

    Sanaz Khorasani

    2012-04-01

    Full Text Available In the title hydrated salt, C8H18N+·C4H5O4−·H2O, the cyclooctyl ring of the cation is disordered over two positions in a 0.833 (3:0.167 (3 ratio. The structure contains various O—H.·O and N—H...O interactions, forming a hydrogen-bonded layer of molecules perpendicular to the c axis. In each layer, the ammonium cation hydrogen bonds to two hydrogen succinate anions and one water molecule. Each hydrogen succinate anion hydrogen bonds to neighbouring anions, forming a chain of molecules along the b axis. In addition, each hydrogen succinate anion hydrogen bonds to two water molecules and the ammonium cation.

  20. End of Life Care and Do Not Resuscitate Orders: How Much Does Age Influence Decision Making? A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Cook, Ifor; Kirkup, Aimee L; Langham, Lauren J; Malik, Muminah A; Marlow, Gabriella; Sammy, Ian

    2017-01-01

    With population aging, "do not resuscitate" (DNAR) decisions, pertaining to the appropriateness of attempting resuscitation following a cardiac arrest, are becoming commoner. It is unclear from the literature whether using age to make these decisions represents "ageism." We undertook a systematic review of the literature using CINAHL, Medline, and the Cochrane database to investigate the relationship between age and DNAR. All 10 studies fulfilling our inclusion criteria found that "do not attempt resuscitation" orders were more prevalent in older patients; eight demonstrated that this was independent of other mediating factors such as illness severity and likely outcome. In studies comparing age groups, the adjusted odds of having a DNAR order were greater in patients aged 75 to 84 and ≥85 years (adjusted odds ratio [AOR] 1.70, 95% confidence interval [CI] = [1.25, 2.33] and 2.96, 95% CI = [2.34, 3.74], respectively), compared with those <65 years. In studies treating age as a continuous variable, there was no significant increase in the use of DNAR with age (AOR 0.98, 95% CI = [0.84, 1.15]). In conclusion, age increases the use of "do not resuscitate" orders, but more research is needed to determine whether this represents "ageism."

  1. End of Life Care and Do Not Resuscitate Orders: How Much Does Age Influence Decision Making? A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Ifor Cook

    2017-06-01

    Full Text Available With population aging, “do not resuscitate” (DNAR decisions, pertaining to the appropriateness of attempting resuscitation following a cardiac arrest, are becoming commoner. It is unclear from the literature whether using age to make these decisions represents “ageism.” We undertook a systematic review of the literature using CINAHL, Medline, and the Cochrane database to investigate the relationship between age and DNAR. All 10 studies fulfilling our inclusion criteria found that “do not attempt resuscitation” orders were more prevalent in older patients; eight demonstrated that this was independent of other mediating factors such as illness severity and likely outcome. In studies comparing age groups, the adjusted odds of having a DNAR order were greater in patients aged 75 to 84 and ≥85 years (adjusted odds ratio [AOR] 1.70, 95% confidence interval [CI] = [1.25, 2.33] and 2.96, 95% CI = [2.34, 3.74], respectively, compared with those <65 years. In studies treating age as a continuous variable, there was no significant increase in the use of DNAR with age (AOR 0.98, 95% CI = [0.84, 1.15]. In conclusion, age increases the use of “do not resuscitate” orders, but more research is needed to determine whether this represents “ageism.”

  2. Influence of the Electrostatic Interaction between a Molecular Catalyst and Semiconductor on Photocatalytic Hydrogen Evolution Activity in Cobaloxime/CdS Hybrid Systems.

    Science.gov (United States)

    Xu, Yuxing; Chen, Ruotian; Li, Zhen; Li, Ailong; Han, Hongxian; Li, Can

    2017-07-12

    The influence of the electrostatic interaction on photocatalytic H 2 evolution activity in cobaloxime/cadmium sulfide (CdS) hybrid systems was studied by measuring the charges of the cobaloximes and the zeta potentials of CdS under different pH conditions (pHs 4-7). Cobaloxime/CdS hybrid systems may have potential as a valid model for the investigation of the electrostatic interaction between a molecular catalyst and semiconductor because the kinetics of methanol oxidation and the driving force of electron transfer from photoirradiated CdS to cobaloxime have little effect on the pH-dependent photocatalytic H 2 evolution activity. Our experimental results suggest that electrostatic repulsion between cobaloxime and CdS disfavors the electron transfer from CdS to cobaloxime and hence lowers the photocatalytic H 2 evolution activity. Whereas, electrostatic attraction favors the electron transfer process and enhances the photocatalytic H 2 evolution activity. However, an electrostatic attraction interaction that is too strong may accelerate both forward and backward electron transfer processes, which would reduce charge separation efficiency and lower photocatalytic H 2 evolution activity.

  3. Optimization of hydrogen and syngas production from PKS gasification by using coal bottom ash.

    Science.gov (United States)

    Shahbaz, Muhammad; Yusup, Suzana; Inayat, Abrar; Patrick, David Onoja; Pratama, Angga; Ammar, Muhamamd

    2017-10-01

    Catalytic steam gasification of palm kernel shell is investigated to optimize operating parameters for hydrogen and syngas production using TGA-MS setup. RSM is used for experimental design and evaluating the effect of temperature, particle size, CaO/biomass ratio, and coal bottom ash wt% on hydrogen and syngas. Hydrogen production appears highly sensitive to all factors, especially temperature and coal bottom ash wt%. In case of syngas, the order of parametric influence is: CaO/biomass>coal bottom ash wt%>temperature>particle size. The significant catalytic effect of coal bottom ash is due to the presence of Fe 2 O 3 , MgO, Al 2 O 3 , and CaO. A temperature of 692°C, coal bottom ash wt% of 0.07, CaO/biomass of 1.42, and particle size of 0.75mm are the optimum conditions for augmented yield of hydrogen and syngas. The production of hydrogen and syngas is 1.5% higher in the pilot scale gasifier as compared to TGA-MS setup. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Redox Control and Hydrogen Production in Sediment Caps Using Carbon Cloth Electrodes

    Science.gov (United States)

    Sun, Mei; Yan, Fei; Zhang, Ruiling; Reible, Danny D.; Lowry, Gregory V.; Gregory, Kelvin B.

    2010-01-01

    Sediment caps that degrade contaminants can improve their ability to contain contaminants relative to sand and sorbent-amended caps, but few methods to enhance contaminant degradation in sediment caps are available. The objective of this study was to determine if, carbon electrodes emplaced within a sediment cap at poised potential could create a redox gradient and provide electron donor for the potential degradation of contaminants. In a simulated sediment cap overlying sediment from the Anacostia River (Washington, DC), electrochemically induced redox gradients were developed within 3 days and maintained over the period of the test (~100 days). Hydrogen and oxygen were produced by water electrolysis at the electrode surfaces and may serve as electron donor and acceptor for contaminant degradation. Electrochemical and geochemical factors that may influence hydrogen production were studied. Hydrogen production displayed zero order kinetics with ~75% coulombic efficiency and rates were proportional to the applied potential between 2.5V to 5V and not greatly affected by pH. Hydrogen production was promoted by increasing ionic strength and in the presence of natural organic matter. Graphite electrode-stimulated degradation of tetrachlorobenzene in a batch reactor was dependent on applied voltage and production of hydrogen to a concentration above the threshold for biological dechlorination. These findings suggest that electrochemical reactive capping can potentially be used to create “reactive” sediments caps capable of promoting chemical or biological transformations of contaminants within the cap. PMID:20879761

  5. The influence of scale size on the stability of periodic solids and the role of associated higher order gradient continuum models

    Science.gov (United States)

    Triantafyllidis, N.; Bardenhagen, S.

    1996-11-01

    Of interest here is the scale size effect on the stability of finitely strained, rate-independent solids with periodic microstructures. Using a multiple scales asymptotic technique, we express the critical load at the onset of the first instability and the corresponding eigenmode in terms of the scale size parameter ɛ. The zeroth order ɛ terms in these expansions depend on the standard (first order gradient) macroscopic moduli tensor, while all the higher order ɛ terms require the determination of higher order gradient macroscopic moduli. These macroscopic moduli, which are calculated by solving appropriate boundary value problems on the unit cell, relate the macroscopic (unit cell average) stress rate increment to the macroscopic displacement rate gradients. The proposed general theory is subsequently applied to the investigation of the failure surfaces in periodic solids of infinite extent. For these solids one can define in macroscopic strain space a microscopic (local) failure surface, which corresponds to the onset of the first bulking-type instability in the solid, and a macroscopic (global) failure surface, which corresponds to the onset of the first long wavelength instability in the solid. The determination of the macrofailure surface is considerably easier than the determination of the microfailure surface, for it requires the calculation of the standard macroscopic moduli tensor. In addition, the regions where the two surfaces coincide is of significant practical interest, for a macroscopic localized mode of deformation (e.g. in the form of a shear band or a kink band) appears in the post-bifurcation regime. The prediction of these coincidence zones is based on a necessary criterion that depends on the higher order gradient macroscopic moduli. A detailed example is given for the case of layered composites, in view of the possibility of obtaining closed form expressions for all the required macroscopic moduli and in view of the existence of an

  6. Hydrogen storage methods

    Science.gov (United States)

    Züttel, Andreas

    Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at Tchemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m-3, approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen is 70.8 kg.m-3, and large volumes, where the thermal losses are small, can cause hydrogen to reach a

  7. Transitions between hyperfine-structure states of the 2s metastable muonic hydrogen in collision processes

    Energy Technology Data Exchange (ETDEWEB)

    Czaplinski, W.

    1992-12-31

    Hyperfine effects in the symmetric collisions of the 2s metastable muonic hydrogen with hydrogen atoms: (p{mu}){sub 2s} + H, (d{mu}){sub 2s} + D, (t{mu}){sub 2s} + t are presented. Elastic and spin-flip cross sections for the scattering of The 2s muonic atoms are calculated in the two-level approximation as a function of collision energy. The corresponding formulae are derived with inclusion of electron screening and Lamb-shift between 2s and 2p energy levels of the muonic atom. The obtained spin-flip cross sections are about two orders of magnitude higher than their ground state counterparts and are much more influenced by electron screening. The rates of the spin-flip transitions are also calculated and are found to be about three orders of magnitude higher than the decay rate of the 2s state. (author). 65 refs, 15 figs, 4 tabs.

  8. Hydrogen sulfide intoxication.

    Science.gov (United States)

    Guidotti, Tee L

    2015-01-01

    Hydrogen sulfide (H2S) is a hazard primarily in the oil and gas industry, agriculture, sewage and animal waste handling, construction (asphalt operations and disturbing marshy terrain), and other settings where organic material decomposes under reducing conditions, and in geothermal operations. It is an insoluble gas, heavier than air, with a very low odor threshold and high toxicity, driven by concentration more than duration of exposure. Toxicity presents in a unique, reliable, and characteristic toxidrome consisting, in ascending order of exposure, of mucosal irritation, especially of the eye ("gas eye"), olfactory paralysis (not to be confused with olfactory fatigue), sudden but reversible loss of consciousness ("knockdown"), pulmonary edema (with an unusually favorable prognosis), and death (probably with apnea contributing). The risk of chronic neurcognitive changes is controversial, with the best evidence at high exposure levels and after knockdowns, which are frequently accompanied by head injury or oxygen deprivation. Treatment cannot be initiated promptly in the prehospital phase, and currently rests primarily on supportive care, hyperbaric oxygen, and nitrite administration. The mechanism of action for sublethal neurotoxicity and knockdown is clearly not inhibition of cytochrome oxidase c, as generally assumed, although this may play a role in overwhelming exposures. High levels of endogenous sulfide are found in the brain, presumably relating to the function of hydrogen sulfide as a gaseous neurotransmitter and immunomodulator. Prevention requires control of exposure and rigorous training to stop doomed rescue attempts attempted without self-contained breathing apparatus, especially in confined spaces, and in sudden release in the oil and gas sector, which result in multiple avoidable deaths. © 2015 Elsevier B.V. All rights reserved.

  9. Pressure-assisted cold denaturation of hen egg white lysozyme: the influence of co-solvents probed by hydrogen exchange nuclear magnetic resonance.

    Science.gov (United States)

    Vogtt, K; Winter, R

    2005-08-01

    COSY proton nuclear magnetic resonance was used to measure the exchange rates of amide protons of hen egg white lysozyme (HEWL) in the pressure-assisted cold-denatured state and in the heat-denatured state. After dissolving lysozyme in deuterium oxide buffer, labile protons exchange for deuterons in such a way that exposed protons are substituted rapidly, whereas "protected" protons within structured parts of the protein are substituted slowly. The exchange rates k obs were determined for HEWL under heat treatment (80 degrees C) and under high pressure conditions at low temperature (3.75 kbar, -13 degrees C). Moreover, the influence of co-solvents (sorbitol, urea) on the exchange rate was examined under pressure-assisted cold denaturation conditions, and the corresponding protection factors, P, were determined. The exchange kinetics upon heat treatment was found to be a two-step process with initial slow exchange followed by a fast one, showing residual protection in the slow-exchange state and P-factors in the random-coil-like range for the final temperature-denatured state. Addition of sorbitol (500 mM) led to an increase of P-factors for the pressure-assisted cold denatured state, but not for the heat-denatured state. The presence of 2 M urea resulted in a drastic decrease of the P-factors of the pressure-assisted cold denatured state. For both types of co-solvents, the effect they exert appears to be cooperative, i.e., no particular regions within the protein can be identified with significantly diverse changes of P-factors.

  10. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    bonding configuration due to hydrogen migration have been proposed as a mechanism of defect generation in a-Si:H [6,7]. Thus hydrogen plays a dual role in a-Si:H: (1) acting as a .... the sphere of radius R0 and allows to express. ∆F as a function of localization radius R0. Using eqs (10) and (11), the volume integration.

  11. Catalytic hydrogenation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Wayland, B.B.

    1992-12-01

    This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form metallo {alpha}-diketone species have suggested a multiplicity of routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in constructing energy profiles for a variety of potential pathways, and these schemes are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Variation of the electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Emerging knowledge of the factors that contribute to M-H, M-C and M-O bond enthalpies is directing the search for ligand arrays that will expand the range of metal species that have favorable thermodynamic parameters to produce the primary intermediates for CO hydrogenation. Studies of rhodium complexes are being extended to non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics. Multifunctional catalyst systems designed to couple the ability of rhodium complexes to produce formyl and diketone intermediates with a second catalyst that hydrogenates these imtermediates are promising approaches to accomplish CO hydrogenation at mild conditions.

  12. Integrated Mirco-Machined Hydrogen Gas Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Frank DiMeoJr. Ing--shin Chen

    2005-12-15

    The widespread use of hydrogen as both an industrial process gas and an energy storage medium requires fast, selective detection of hydrogen gas. This report discusses the development of a new type of solid-state hydrogen gas sensor that couples novel metal hydride thin films with a MEMS (Micro-Electro-Mechanical System) structure known as a micro-hotplate. In this project, Micro-hotplate structures were overcoated with engineered multilayers that serve as the active hydrogen-sensing layer. The change in electrical resistance of these layers when exposed to hydrogen gas was the measured sensor output. This project focused on achieving the following objectives: (1) Demonstrating the capabilities of micro-machined H2 sensors; (2) Developing an understanding of their performance; (3) Critically evaluating the utility and viability of this technology for life safety and process monitoring applications. In order to efficiently achieve these objectives, the following four tasks were identified: (1) Sensor Design and Fabrication; (2) Short Term Response Testing; (3) Long Term Behavior Investigation; (4) Systems Development. Key findings in the project include: The demonstration of sub-second response times to hydrogen; measured sensitivity to hydrogen concentrations below 200 ppm; a dramatic improvement in the sensor fabrication process and increased understanding of the processing properties and performance relationships of the devices; the development of improved sensing multilayers; and the discovery of a novel strain based hydrogen detection mechanism. The results of this program suggest that this hydrogen sensor technology has exceptional potential to meet the stringent demands of life safety applications as hydrogen utilization and infrastructure becomes more prevalent.

  13. Hydrogen Production for Refuelling Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hulteberg, Christian; Aagesen, Diane (Intelligent Energy, Long Beach, CA (United States))

    2009-08-15

    The aim of this work is to support the development of a high-profile demonstration of hydrogen generation technologies in a Swedish context. The overall objective of the demonstration is to deploy a reforming based hydrogen refilling station along the Swedish west coast; intermediate to the Malmoe refuelling station and planned stations in Goeteborg. In this way, the Norwegian hydrogen highway will be extended through the south of Sweden and down into Denmark. The aim of the project's first phase, where this constitutes the final report, was to demonstrate the ability to operate the IE reforming system on the E.On/SGC site-specific fuel. During the project, a preliminary system design has been developed, based on IE's proprietary reformer. The system has been operated at pressure, to ensure a stable operation of the downstream PSA; which has been operated without problems and with the expected hydrogen purity and recovery. The safe operation of the proposed and tested system was first evaluated in a preliminary risk assessment, as well as a full HazOp analysis. A thorough economic modelling has been performed on the viability of owning and operating this kind of hydrogen generation equipment. The evaluation has been performed from an on-site operation of such a unit in a refuelling context. The general conclusion from this modelling is that there are several parameters that influence the potential of an investment in a Hestia hydrogen generator. The sales price of the hydrogen is one of the major drivers of profitability. Another important factor is the throughput of the unit, more important than efficiency and utilization. Varying all of the parameters simultaneously introduce larger variations in the NPV, but 60% of the simulations are in the USD 90 000 to USD 180 000 interval. The chosen intervals for the parameters were: Hydrogen Sales Price (USD 5 - USD 7 per kg); Investment Cost (USD 70 000 - USD 130 000 per unit); Throughput (20 - 30 kg

  14. Diffusion of hydrogen interstitials in the near-surface region of Pd(111) under the influence of surface coverage and external static electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Rey, M. [Departamento de Física de Materiales, Facultad de Químicas UPV/EHU, Apartado 1072, 20018 Donostia-San Sebastián (Spain); Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián (Spain); Tremblay, J. C. [Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 3, D-14195 Berlin (Germany)

    2015-04-21

    Past scanning tunneling microscopy (STM) experiments of H manipulation on Pd(111), at low temperature, have shown that it is possible to induce diffusion of surface species as well as of those deeply buried under the surface. Several questions remain open regarding the role of subsurface site occupancies. In the present work, the interaction potential of H atoms with Pd(111) under various H coverage conditions is determined by means of density functional theory calculations in order to provide an answer to two of these questions: (i) whether subsurface sites are the final locations for the H impurities that attempt to emerge from bulk regions, and (ii) whether penetration of the surface is a competing route of on-surface diffusion during depletion of surface H on densely covered Pd(111). We find that a high H coverage has the effect of blocking resurfacing of H atoms travelling from below, which would otherwise reach the surface fcc sites, but it hardly alters deeper diffusion energy barriers. Penetration is unlikely and restricted to high occupancies of hcp hollows. In agreement with experiments, the Pd lattice expands vertically as a consequence of H atoms being blocked at subsurface sites, and surface H enhances this expansion. STM tip effects are included in the calculations self-consistently as an external static electric field. The main contribution to the induced surface electric dipoles originates from the Pd substrate polarisability. We find that the electric field has a non-negligible effect on the H-Pd potential in the vicinity of the topmost Pd atomic layer, yet typical STM intensities of 1-2 VÅ{sup −1} are insufficient to invert the stabilities of the surface and subsurface equilibrium sites.

  15. Highly hydrogenated graphene via active hydrogen reduction of graphene oxide in the aqueous phase at room temperature.

    Science.gov (United States)

    Sofer, Zdeněk; Jankovský, Ondřej; Šimek, Petr; Soferová, Lýdie; Sedmidubský, David; Pumera, Martin

    2014-02-21

    Hydrogenated graphene and graphane are in the forefront of graphene research. Hydrogenated graphene is expected to exhibit ferromagnetism, tunable band gap, fluorescence, and high thermal and low electrical conductivity. Currently available techniques for fabrication of highly hydrogenated graphene use either a liquid ammonia (-33 °C) reduction pathway using alkali metals or plasma low pressure or ultra high pressure hydrogenation. These methods are either technically challenging or pose inherent risks. Here we wish to demonstrate that highly hydrogenated graphene can be prepared at room temperature in the aqueous phase by reduction of graphene oxide by nascent hydrogen generated by dissolution of metal in acid. Nascent hydrogen is known to be a strong reducing agent. We studied the influence of metal involved in nascent hydrogen generation and characterized the samples in detail. The resulting reduced graphenes and hydrogenated graphenes were characterized in detail. The resulting hydrogenated graphene had the chemical formula C1.16H1O0.66. Such simple hydrogenation of graphene is of high importance for large scale safe synthesis of hydrogenated graphene.

  16. Water content and porosity effect on hydrogen radiolytic yields of geopolymers

    Science.gov (United States)

    Chupin, Frédéric; Dannoux-Papin, Adeline; Ngono Ravache, Yvette; d'Espinose de Lacaillerie, Jean-Baptiste

    2017-10-01

    The behavior of geopolymers under irradiation is a topic that has not been thoroughly investigated so far. However, if geopolymers are considered to be used as radioactive waste embedding matrices, their chemical and mechanical stability under ionizing radiation as well as low hydrogen production must be demonstrated. For that purpose, a particular focus is put on water radiolysis. Various formulations of geopolymers have been irradiated either with γ-rays (60Co source) or 95 MeV/amu 36Ar18+ ions beams and the hydrogen production has been quantified. This paper presents the results of radiolytic gas analysis in order to identify important structural parameters that influence confined water radiolysis. A correlation between geopolymers nature, water content on the one side, and the hydrogen radiolytic yield (G(H2)) on the other side, has been demonstrated. For both types of irradiations, a strong influence of the water content on the hydrogen radiolytic yield G(H2) is evidenced. The geopolymers porosity effect has been only highlighted under γ-rays irradiation.

  17. Controlling residual hydrogen gas in mass spectra during pulsed laser atom probe tomography.

    Science.gov (United States)

    Kolli, R Prakash

    2017-01-01

    Residual hydrogen (H2) gas in the analysis chamber of an atom probe instrument limits the ability to measure H concentration in metals and alloys. Measuring H concentration would permit quantification of important physical phenomena, such as hydrogen embrittlement, corrosion, hydrogen trapping, and grain boundary segregation. Increased insight into the behavior of residual H2 gas on the specimen tip surface in atom probe instruments could help reduce these limitations. The influence of user-selected experimental parameters on the field adsorption and desorption of residual H2 gas on nominally pure copper (Cu) was studied during ultraviolet pulsed laser atom probe tomography. The results indicate that the total residual hydrogen concentration, HTOT, in the mass spectra exhibits a generally decreasing trend with increasing laser pulse energy and increasing laser pulse frequency. Second-order interaction effects are also important. The pulse energy has the greatest influence on the quantity HTOT, which is consistently less than 0.1 at.% at a value of 80 pJ.

  18. Overview of hydrogen production program in HTTR

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Yoshiaki; Shiozawa, Shusaku; Ogawa, Masuro; Hada, Kazuhiko; Inagaki, Yoshiyuki; Takeda, Tetsuaki; Nishihara, Tetsuo [Department of Advanced Nuclear Heat Technology, Japan Atomic Energy Research Institute JAERI, Ibaraki-ken (Japan)

    1998-09-01

    A demonstration program on hydrogen production has been started in January 1997. Using nuclear heat (10MW, 905C, and 4.1MPa) supplied by the High Temperature engineering Test Reactor (HTTR), a hydrogen production system is being designed to be able to produce hydrogen with the production rate of approximately 4000 Nm{sup 3}/hr, which is in a range of commercial level, by steam reforming of natural gas. The safety principle and standard are also being investigated for nuclear heat utilization systems connected to High Temperature Gas-cooled Reactors (HTGRs) including the HTTR. The HTTR hydrogen production system is first connected to a nuclear power reactor, hence an out-of-pile test, a hydrogen permeation test and a corrosion test of a catalyst tube of the steam reformer are carried out prior to the demonstration test of the HTTR hydrogen production system. In order to confirm controllability, safety, and performance of key components in the HTTR hydrogen production system, the facility for the out-of-pile test is being designed and manufactured on the scale of approximately 1/30 of the HTTR hydrogen production system. It is equipped with an electrical heater as a heat source instead of the HTTR. The out-of-pile test will be started in the year 2000 and will be performed for 4 years. Check and review of the demonstration program in the HTTR will be made in 2000 from the view point of economy and technology, then the HTTR hydrogen production system will be constructed in 2001 and will be demonstratively operated in the period 2005-2010. The hydrogen/tritium permeation test is carried out in 1998 to obtain the data on hydrogen/tritium permeation coefficients for mainly the Hastelloy-XR, which is a nickel-base helium corrosion- and heat-resistance super alloy and is used in high temperature components of the HTTR and the HTTR hydrogen production system, and to verify the reduction method of the hydrogen/tritium permeation through the tube wall to the helium coolant

  19. Design of control algorithm over technical condition of hydrogen generators based on hydro-reactive compositions

    OpenAIRE

    Abramov, Yuriy; Borisenko, Vitaliy; Krivtsova, Valentina

    2017-01-01

    In order to describe the process of hydrogen generation, a system of differential equations is applied, which is matched with a transfer function of the hydrogen generator. A transfer function of the hydrogen generator is used for the transition to the frequency domain of research. We obtained an expression for the asymptotic logarithmic amplitude-frequency characteristic of the hydrogen generator. This characteristic is used to identify a simplified description of the hydrogen generator, whi...

  20. Influence of the Cu Content in Cu2ZnSn(S,Se)4 solar cell absorbers on order-disorder related band gap changes

    Science.gov (United States)

    Lang, Mario; Renz, Tobias; Mathes, Niklas; Neuwirth, Markus; Schnabel, Thomas; Kalt, Heinz; Hetterich, Michael

    2016-10-01

    We investigate the electronic structure and the radiative recombination in wet-chemically fabricated Cu2ZnSn(S,Se)4 solar cell absorbers utilizing photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy, focusing especially on the effects of varying Cu content. This includes the impact of the latter on the band gap energy and the change in band gap energy related to the order-disorder transition. Characteristic PL and PLE parameters like the energetic position of the PL maximum and the PL yield as a function of the excitation power as well as the PLE tailing parameter do not depend on composition indicating that the nature of the radiative transition is not altered by the Cu content. However, the band gap energy Eg significantly increases as a function of decreasing Cu content. This increase is more pronounced in the disordered than in the ordered atomic arrangement of Cu and Zn atoms in the Cu-Zn planes of the kesterite crystal structure.

  1. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Steinbugler, M.; Kreutz, T. [Princeton Univ., NJ (United States). Center for Energy and Environmental Studies

    1998-08-01

    In this progress report (covering the period May 1997--May 1998), the authors summarize results from ongoing technical and economic assessments of hydrogen energy systems. Generally, the goal of their research is to illuminate possible pathways leading from present hydrogen markets and technologies toward wide scale use of hydrogen as an energy carrier, highlighting important technologies for RD and D. Over the past year they worked on three projects. From May 1997--November 1997, the authors completed an assessment of hydrogen as a fuel for fuel cell vehicles, as compared to methanol and gasoline. Two other studies were begun in November 1997 and are scheduled for completion in September 1998. The authors are carrying out an assessment of potential supplies and demands for hydrogen energy in the New York City/New Jersey area. The goal of this study is to provide useful data and suggest possible implementation strategies for the New York City/ New Jersey area, as the Hydrogen Program plans demonstrations of hydrogen vehicles and refueling infrastructure. The authors are assessing the implications of CO{sub 2} sequestration for hydrogen energy systems. The goals of this work are (a) to understand the implications of CO{sub 2} sequestration for hydrogen energy system design; (b) to understand the conditions under which CO{sub 2} sequestration might become economically viable; and (c) to understand design issues for future low-CO{sub 2} emitting hydrogen energy systems based on fossil fuels.

  2. Hydrogen sensor based on metallic photonic crystal slabs.

    Science.gov (United States)

    Nau, D; Seidel, A; Orzekowsky, R B; Lee, S-H; Deb, S; Giessen, H

    2010-09-15

    We present a hydrogen sensor based on metallic photonic crystal slabs. Tungsten trioxide (WO(3)) is used as a waveguide layer below an array of gold nanowires. Hydrogen exposure influences the optical properties of this photonic crystal arrangement by gasochromic mechanisms, where the photonic crystal geometry leads to sharp spectral resonances. Measurements reveal a change of the transmission depending on the hydrogen concentration. Theoretical limits for the detection range and sensitivity of this approach are discussed.

  3. Hydrogen induced cracking tests of high strength steels and nickel-iron base alloys using the bolt-loaded specimen

    Energy Technology Data Exchange (ETDEWEB)

    Vigilante, G.N.; Underwood, J.H.; Crayon, D.; Tauscher, S.; Sage, T.; Troiano, E. [Army Armament RD and E Center, Watervliet, NY (United States). Benet Labs.

    1997-12-31

    Hydrogen induced cracking tests were conducted on high strength steels and nickel-iron base alloys using the constant displacement bolt-loaded compact specimen. The bolt-loaded specimen was subjected to both acid and electrochemical cell environments in order to produce hydrogen. The materials tested were A723, Maraging 200, PH 13-8 Mo, Alloy 718, Alloy 706, and A286, and ranged in yield strength from 760--1400 MPa. The effects of chemical composition, refinement, heat treatment, and strength on hydrogen induced crack growth rates and thresholds were examined. In general, all high strength steels tested exhibited similar crack growth rates and thresholds were examined. In general, all high strength steels tested exhibited similar crack growth rates and threshold levels. In comparison, the nickel-iron base alloys tested exhibited up to three orders of magnitude lower crack growth rates than the high strength steels tested. It is widely known that high strength steels and nickel base alloys exhibit different crack growth rates, in part, because of their different crystal cell structure. In the high strength steels tested, refinement and heat treatment had some effect on hydrogen induced cracking, though strength was the predominant factor influencing susceptibility to cracking. When the yield strength of one of the high strength steels tested was increased moderately, from 1130 MPa to 1275 MPa, the incubation times decreased by over two orders of magnitude, the crack growth rates increased by an order of magnitude, and the threshold stress intensity was slightly lower.

  4. Influence of the phenomena occurring at the interface between L1{sub 0}-ordered-FePt and Fe on the coercivity behavior

    Energy Technology Data Exchange (ETDEWEB)

    Carbucicchio, Massimo, E-mail: massimo.carbucicchio@ino.it [University of Parma, Physics Department (Italy)

    2016-12-15

    L1{sub 0}-ordered FePt/Fe thin bi-layers were grown using a molecular beam epitaxy onto (100)-MgO substrates changing the soft Fe layer thickness. The study of the intermixing phenomena occurring at the hard/soft interfaces was carried out using surface Mössbauer spectroscopy. The magnetic properties of the samples were analyzed with a magneto-optical Kerr effect magnetometer. The surface morphology and the magnetic domains were analyzed with an UHV atomic and magnetic force microscopy in tapping and lift mode respectively.The present work clearly demonstrates that the degree of interface intermixing and reactions is the responsible for the coercivity behavior in exchange-spring magnets.

  5. Task-irrelevant sounds influence both temporal order and apparent-motion judgments about tactile stimuli applied to crossed and uncrossed hands.

    Science.gov (United States)

    Badde, Stephanie; Röder, Brigitte; Bruns, Patrick

    2017-12-27

    It has been suggested that judgments about the temporal-spatial order of successive tactile stimuli depend on the perceived direction of apparent motion between them. Here we manipulated tactile apparent-motion percepts by presenting a brief, task-irrelevant auditory stimulus temporally in-between pairs of tactile stimuli. The tactile stimuli were applied one to each hand, with varying stimulus onset asynchronies (SOAs). Participants reported the location of the first stimulus (temporal order judgments: TOJs) while adopting both crossed and uncrossed hand postures, so we could scrutinize skin-based, anatomical, and external reference frames. With crossed hands, the sound improved TOJ performance at short (≤300 ms) and at long (>300 ms) SOAs. When the hands were uncrossed, the sound induced a decrease in TOJ performance, but only at short SOAs. A second experiment confirmed that the auditory stimulus indeed modulated tactile apparent motion perception under these conditions. Perceived apparent motion directions were more ambiguous with crossed than with uncrossed hands, probably indicating competing spatial codes in the crossed posture. However, irrespective of posture, the additional sound tended to impair potentially anatomically coded motion direction discrimination at a short SOA of 80 ms, but it significantly enhanced externally coded apparent motion perception at a long SOA of 500 ms. Anatomically coded motion signals imply incorrect TOJ responses with crossed hands, but correct responses when the hands are uncrossed; externally coded motion signals always point toward the correct TOJ response. Thus, taken together, these results suggest that apparent-motion signals are likely taken into account when tactile temporal-spatial information is reconstructed.

  6. Hydrogen storage on high-surface-area carbon monoliths for Adsorb hydrogen Gas Vehicle

    Science.gov (United States)

    Soo, Yuchoong; Pfeifer, Peter

    2014-03-01

    Carbon briquetting can increase hydrogen volumetric storage capacity by reducing the useless void volume resulting in a better packing density. It is a robust and efficient space-filling form for an adsorbed hydrogen gas vehicle storage tank. To optimize hydrogen storage capacity, we studied three fabrication process parameters: carbon-to-binder ratio, compaction temperature, and pyrolysis atmosphere. We found that carbon-to-binder ratio and pyrolysis atmosphere have influences on gravimetric excess adsorption. Compaction temperature has large influences on gravimetric and volumetric storage capacity. We have been able to optimize these parameters for high hydrogen storage. All monolith uptakes (up to 260 bar) were measured by a custom-built, volumetric, reservoir-type instrument.

  7. Order of amino acids in C-terminal cysteine-containing peptide-based chelators influences cellular processing and biodistribution of 99mTc-labeled recombinant Affibody molecules.

    Science.gov (United States)

    Altai, Mohamed; Wållberg, Helena; Orlova, Anna; Rosestedt, Maria; Hosseinimehr, Seyed Jalal; Tolmachev, Vladimir; Ståhl, Stefan

    2012-05-01

    Affibody molecules constitute a novel class of molecular display selected affinity proteins based on non-immunoglobulin scaffold. Preclinical investigations and pilot clinical data have demonstrated that Affibody molecules provide high contrast imaging of tumor-associated molecular targets shortly after injection. The use of cysteine-containing peptide-based chelators at the C-terminus of recombinant Affibody molecules enabled site-specific labeling with the radionuclide 99mTc. Earlier studies have demonstrated that position, composition and the order of amino acids in peptide-based chelators influence labeling stability, cellular processing and biodistribution of Affibody molecules. To investigate the influence of the amino acid order, a series of anti-HER2 Affibody molecules, containing GSGC, GEGC and GKGC chelators have been prepared and characterized. The affinity to HER2, cellular processing of 99mTc-labeled Affibody molecules and their biodistribution were investigated. These properties were compared with that of the previously studied 99mTc-labeled Affibody molecules containing GGSC, GGEC and GGKC chelators. All variants displayed picomolar affinities to HER2. The substitution of a single amino acid in the chelator had an appreciable influence on the cellular processing of 99mTc. The biodistribution of all 99mTc-labeled Affibody molecules was in general comparable, with the main difference in uptake and retention of radioactivity in excretory organs. The hepatic accumulation of radioactivity was higher for the lysine-containing chelators and the renal retention of 99mTc was significantly affected by the amino acid composition of chelators. The order of amino acids influenced renal uptake of some conjugates at 1 h after injection, but the difference decreased at later time points. Such information can be helpful for the development of other scaffold protein-based imaging and therapeutic radiolabeled conjugates.

  8. The hydrogen bond in the solid state.

    Science.gov (United States)

    Steiner, Thomas

    2002-01-04

    The hydrogen bond is the most important of all directional intermolecular interactions. It is operative in determining molecular conformation, molecular aggregation, and the function of a vast number of chemical systems ranging from inorganic to biological. Research into hydrogen bonds experienced a stagnant period in the 1980s, but re-opened around 1990, and has been in rapid development since then. In terms of modern concepts, the hydrogen bond is understood as a very broad phenomenon, and it is accepted that there are open borders to other effects. There are dozens of different types of X-H.A hydrogen bonds that occur commonly in the condensed phases, and in addition there are innumerable less common ones. Dissociation energies span more than two orders of magnitude (about 0.2-40 kcal mol(-1)). Within this range, the nature of the interaction is not constant, but its electrostatic, covalent, and dispersion contributions vary in their relative weights. The hydrogen bond has broad transition regions that merge continuously with the covalent bond, the van der Waals interaction, the ionic interaction, and also the cation-pi interaction. All hydrogen bonds can be considered as incipient proton transfer reactions, and for strong hydrogen bonds, this reaction can be in a very advanced state. In this review, a coherent survey is given on all these matters.

  9. Investigation of Atomic Physics and Frequency Stability with a Croygenic Hydrogen Laser

    National Research Council Canada - National Science Library

    Walsworth, Ronald

    1997-01-01

    .... The cryogenic hydrogen maser (CHM) operates at low temperatures, and may provide frequency stability that is one to three orders of magnitude better than a room temperature hydrogen maser because of greatly reduced thermal noise and larger signal power...

  10. Catalytic Hydrogenation Reaction of Naringin-Chalcone. Study of the Electrochemical Reaction

    Directory of Open Access Journals (Sweden)

    B. A. López de Mishima

    2000-03-01

    Full Text Available The electrocatalytic hydrogenation reaction of naringin derivated chalcone is studied. The reaction is carried out with different catalysts in order to compare with the classic catalytic hydrogenation.

  11. Allylammonium hydrogen oxalate hemihydrate

    Directory of Open Access Journals (Sweden)

    Błażej Dziuk

    2014-08-01

    Full Text Available In the title hydrated molecular salt, C3H8N+·C2HO4−·0.5H2O, the water O atom lies on a crystallographic twofold axis. The C=C—C—N torsion angle in the cation is 2.8 (3° and the dihedral angle between the CO2 and CO2H planes in the anion is 1.0 (4°. In the crystal, the hydrogen oxalate ions are linked by O—H...O hydrogen bonds, generating [010] chains. The allylammonium cations bond to the chains through N—H...O and N—H...(O,O hydrogen bonds. The water molecule accepts two N—H...O hydrogen bonds and makes two O—H...O hydrogen bonds. Together, the hydrogen bonds generate (100 sheets.

  12. Hydrogen Fuelling Stations

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus Damgaard

    This thesis concerns hydrogen fuelling stations from an overall system perspective. The study investigates thermodynamics and energy consumption of hydrogen fuelling stations for fuelling vehicles for personal transportation. For the study a library concerning the components in a hydrogen fuelling...... station has been developed in Dymola. The models include the fuelling protocol (J2601) for hydrogen vehicles made by Society of Automotive Engineers (SAE) and the thermodynamic property library CoolProp is used for retrieving state point. The components in the hydrogen fuelling library are building up....... A system consisting of one high pressure storage tank is used to investigate the thermodynamics of fuelling a hydrogen vehicle. The results show that the decisive parameter for how the fuelling proceeds is the pressure loss in the vehicle. The single tank fuelling system is compared to a cascade fuelling...

  13. Interaction between an icosahedron Li(13) cluster and a graphene layer doped with a hydrogen atom.

    Science.gov (United States)

    Rangel, Eduardo; Vázquez, Gerardo; Magaña, Fernando; Sansores, Enrique

    2012-12-01

    It is known that graphene reacts with atomic hydrogen to form a hydrogenated sheet of graphene. In order to understand the nature of the interaction between hydrogen and lithium in hydrogenated samples, we have carried out first principle calculations. Density functional theory and molecular dynamics were used to study the interaction between an icosahedron Li(13) cluster, and a graphene layer doped with a hydrogen atom. It was found that a hydrogen atom is levitated from the graphene layer and absorbed into the cluster of Li at 300 K and atmospheric pressure, with a binding energy far exceeding that of the adsorption energy of a hydrogen atom on the graphene layer.

  14. Influence of disorder on ageing and memory effects in non-equilibrium critical dynamics of 3D Ising model relaxing from an ordered state

    Science.gov (United States)

    Prudnikov, Vladimir V.; Prudnikov, Pavel V.; Pospelov, Evgeny A.

    2016-04-01

    We have performed a numerical investigation of the influence of disorder on the dynamical non-equilibrium evolution of a 3D site-diluted Ising model from a low-temperature initial state with magnetization m 0  =  1. It is shown that two-time dependences of the autocorrelation and integrated response functions for systems with spin concentrations p  =  1.0, 0.95, 0.8, 0.6 and 0.5 demonstrate ageing properties with anomalous slowing-down relaxation and violation of the fluctuation-dissipation ratio. It was revealed that during non-equilibrium critical dynamics in the long-time regime t-{{t}\\text{w}}\\gg {{t}\\text{w}}\\gg 1 the autocorrelation functions for diluted systems are extremely slow due to the pinning of domain walls on impurity sites. We have found that the fluctuation-dissipation ratio {{X}∞}=0 for diluted systems with spin concentration p  memory effects for critical evolution in the ageing regime with realization of cyclic temperature change and quenching at T<{{T}\\text{c}} .

  15. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Steinbugler, M.; Dennis, E. [Princeton Univ., NJ (United States)] [and others

    1995-09-01

    For several years, researchers at Princeton University`s Center for Energy and Environmental Studies have carried out technical and economic assessments of hydrogen energy systems. Initially, we focussed on the long term potential of renewable hydrogen. More recently we have explored how a transition to renewable hydrogen might begin. The goal of our current work is to identify promising strategies leading from near term hydrogen markets and technologies toward eventual large scale use of renewable hydrogen as an energy carrier. Our approach has been to assess the entire hydrogen energy system from production through end-use considering technical performance, economics, infrastructure and environmental issues. This work is part of the systems analysis activity of the DOE Hydrogen Program. In this paper we first summarize the results of three tasks which were completed during the past year under NREL Contract No. XR-11265-2: in Task 1, we carried out assessments of near term options for supplying hydrogen transportation fuel from natural gas; in Task 2, we assessed the feasibility of using the existing natural gas system with hydrogen and hydrogen blends; and in Task 3, we carried out a study of PEM fuel cells for residential cogeneration applications, a market which might have less stringent cost requirements than transportation. We then give preliminary results for two other tasks which are ongoing under DOE Contract No. DE-FG04-94AL85803: In Task 1 we are assessing the technical options for low cost small scale production of hydrogen from natural gas, considering (a) steam reforming, (b) partial oxidation and (c) autothermal reforming, and in Task 2 we are assessing potential markets for hydrogen in Southern California.

  16. Pathways to Metallic Hydrogen

    OpenAIRE

    Silvera, Isaac F.; Deemyad, Shanti

    2008-01-01

    The traditional pathway that researchers have used in the goal of producing atomic metallic hydrogen is to compress samples with megabar pressures at low temperature. A number of phases have been observed in solid hydrogen and its isotopes, but all are in the insulating phase. The results of experiment and theory for this pathway are reviewed. In recent years a new pathway has become the focus of this challenge of producing metallic hydrogen, namely a path along the melting line. It has bee...

  17. Hydrogen rich gas generator

    Science.gov (United States)

    Houseman, J. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by introducing a liquid hydrocarbon fuel in the form of a spray into a partial oxidation region and mixing with a mixture of steam and air that is preheated by indirect heat exchange with the formed hydrogen rich gas, igniting the hydrocarbon fuel spray mixed with the preheated mixture of steam and air within the partial oxidation region to form a hydrogen rich gas.

  18. Hydrogen Fuel Cell Vehicles

    OpenAIRE

    Delucchi, Mark

    1992-01-01

    Hydrogen is an especially attractive transportation fuel. It is the least polluting fuel available, and can be produced anywhere there is water and a clean source of electricity. A fuel cycle in which hydrogen is produced by solar-electrolysis of water, or by gasification of renewably grown biomass, and then used in a fuel-cell powered electric-motor vehicle (FCEV), would produce little or no local, regional, or global pollution. Hydrogen FCEVs would combine the best features of bat...

  19. EXPERIMENTAL STUDY OF THE THERMAL BEHAVIOUR OF HYDROGEN TANKS DURING HYDROGEN CYCLING

    OpenAIRE

    DE MIGUEL ECHEVARRIA NEREA; Acosta Iborra, Beatriz; Moretto, Pietro; HARSKAMP Frederik; BONATO CHRISTIAN

    2013-01-01

    The thermal behaviour of several commercial hydrogen tanks has been studied during high pressure (70-84 MPa) hydrogen cycling. The temperature of the gas at different points inside the tank, the temperature at the bosses and the tank outer wall temperature have been measured under different filling and emptying conditions. From the experimental results, the effect of the filling rate (1.5-4 g/s) and the influence of the liner material in the thermal behaviour of the hydrogen tanks have been e...

  20. Influence of Rabbit Sire Genetic Origin, Season of Birth and Parity Order on Doe and Litter Performance in an Organic Production System

    Directory of Open Access Journals (Sweden)

    Antonella Dalle Zotte

    2013-01-01

    Full Text Available The aim of this study was to compare both the performance of litters derived from two sire genetic origins (SGO, Vienna Blue (VB and Burgundy Fawn (BF, along successive seasons of birth (SB; winter, spring, summer and autumn, and doe reproductive performance in an organic production system. A total of fifty-eight does consisting of a mixture of crosses of several medium-large size breeds at different parity order (P, 1 = nulliparous; 2 = primiparous; ≥3 = multiparous and twelve males (6 VB and 6 BF were housed indoors at environmental conditions that followed seasonality. An extensive reproductive rhythm was used and kits were weaned at 46±6 d of age. Doe reproductive performance and the data of 105 litters (55 from VB and 50 from BF SGO were recorded throughout the SB. No statistically significant differences related to SGO effect were observed. As regards parity order, multiparous does showed higher live weights (LW (p<0.05, total born (p<0.01, total born alive (p<0.05 per delivery, and litter weight of born alive (p<0.05, but lower milk output at 21st d than primiparous does (p<0.05. The extensive reproductive rhythm mainly increased litter performance at birth in multiparous does but was not sufficient to permit a complete recovery of body reserves lost during lactation. Autumn SB negatively affected doe LW variation between deliveries. The number of pups born and born alive per delivery (p<0.05 and litter size at 21 d of age and at weaning (p<0.01 were lower during hot SB. Due to the lower litter size of pups born in summer and autumn, their individual weight at 21st d of age and daily individual growth rate 0 to 21 d were higher than those of pups born in winter (p<0.001. Litter performance at 21st d of age and individual pup pre-weaning growth rate were poorer for those born in spring than in other seasons due to the harmful effects of increased environmental temperatures. SB affected most of the performance traits of does and young

  1. Hydrogen Storage Technologies for Future Energy Systems.

    Science.gov (United States)

    Preuster, Patrick; Alekseev, Alexander; Wasserscheid, Peter

    2017-06-07

    Future energy systems will be determined by the increasing relevance of solar and wind energy. Crude oil and gas prices are expected to increase in the long run, and penalties for CO 2 emissions will become a relevant economic factor. Solar- and wind-powered electricity will become significantly cheaper, such that hydrogen produced from electrolysis will be competitively priced against hydrogen manufactured from natural gas. However, to handle the unsteadiness of system input from fluctuating energy sources, energy storage technologies that cover the full scale of power (in megawatts) and energy storage amounts (in megawatt hours) are required. Hydrogen, in particular, is a promising secondary energy vector for storing, transporting, and distributing large and very large amounts of energy at the gigawatt-hour and terawatt-hour scales. However, we also discuss energy storage at the 120-200-kWh scale, for example, for onboard hydrogen storage in fuel cell vehicles using compressed hydrogen storage. This article focuses on the characteristics and development potential of hydrogen storage technologies in light of such a changing energy system and its related challenges. Technological factors that influence the dynamics, flexibility, and operating costs of unsteady operation are therefore highlighted in particular. Moreover, the potential for using renewable hydrogen in the mobility sector, industrial production, and the heat market is discussed, as this potential may determine to a significant extent the future economic value of hydrogen storage technology as it applies to other industries. This evaluation elucidates known and well-established options for hydrogen storage and may guide the development and direction of newer, less developed technologies.

  2. Liquid hydrogen in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, S. [Iwatani Corp., Osaka (Japan). Dept. of Overseas Business Development

    2009-07-01

    Japan's Iwatani Corporation has focused its attention on hydrogen as the ultimate energy source in future. Unlike the United States, hydrogen use and delivery in liquid form is extremely limited in the European Union and in Japan. Iwatani Corporation broke through industry stereotypes by creating and building Hydro Edge Co. Ltd., Japan's largest liquid hydrogen plant. It was established in 2006 as a joint venture between Iwatani and Kansai Electric Power Group in Osaka. Hydro Edge is Japan's first combined liquid hydrogen and ASU plant, and is fully operational. Liquid oxygen, liquid nitrogen and liquid argon are separated from air using the cryogenic energy of liquefied natural gas fuel that is used for power generation. Liquid hydrogen is produced efficiently and simultaneously using liquid nitrogen. Approximately 12 times as much hydrogen in liquid form can be transported and supplied as pressurized hydrogen gas. This technology is a significant step forward in the dissemination and expansion of hydrogen in a hydrogen-based economy.

  3. Water, Hydrogen Bonding and the Microwave Background

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-04-01

    Full Text Available n this work, the properties of the water are briefly revisited. Though liquid water has a fleeting structure, it displays an astonishingly stable network of hydrogen bonds. Thus, even as a liquid, water possesses a local lattice with short range order. The presence of hydroxyl (O-H and hydrogen (H....OH2 bonds within water, indicate that it can simultaneously maintain two separate energy systems. These can be viewed as two very different temperatures. The analysis presented uses results from vibrational spec- troscopy, extracting the force constant for the hydrogen bonded dimer. By idealizing this species as a simple diatomic structure, it is shown that hydrogen bonds within wa- ter should be able to produce thermal spectra in the far infrared and microwave regions of the electromagnetic spectrum. This simple analysis reveals that the oceans have a physical mechanism at their disposal, which is capable of generating the microwave background.

  4. Pad B Liquid Hydrogen Storage Tank

    Science.gov (United States)

    Hall, Felicia

    2007-01-01

    Kennedy Space Center is home to two liquid hydrogen storage tanks, one at each launch pad of Launch Complex 39. The liquid hydrogen storage tank at Launch Pad B has a significantly higher boil off rate that the liquid hydrogen storage tank at Launch Pad A. This research looks at various calculations concerning the at Launch Pad B in an attempt to develop a solution to the excess boil off rate. We will look at Perlite levels inside the tank, Boil off rates, conductive heat transfer, and radiant heat transfer through the tank. As a conclusion to the research, we will model the effects of placing an external insulation to the tank in order to reduce the boil off rate and increase the economic efficiency of the liquid hydrogen storage tanks.

  5. Evaluation of ordered mesoporous silica as a carrier for poorly soluble drugs: influence of pressure on the structure and drug release.

    Science.gov (United States)

    Vialpando, Monica; Aerts, Alexander; Persoons, Jeroen; Martens, Johan; Van Den Mooter, Guy

    2011-08-01

    Ordered mesoporous silica (OMS) materials are considered a promising drug delivery system for the dissolution enhancement of poorly soluble compounds. The purpose of the present work was to determine structural and behavioral changes of compressed OMS material necessary for the development of an immediate-release oral-dosage formulation. Two types of OMS materials (SBA-15 and COK-12) were subjected to pressures both in and beyond the tabletting region and characterized by nitrogen physisorption, scanning and transmission electron microscopy, small-angle X-ray scattering, and differential scanning calorimetry. Itraconazole was used as the poorly soluble model drug and the release process with respect to pressure was determined in vitro. The resulting decreased drug release due to increased pressure was recovered by incorporating a plastically deforming material such as microcrystalline cellulose in combination with croscarmellose sodium. These findings further elucidate the understanding of their structural behavior for the advancement as a drug delivery carrier. Copyright © 2011 Wiley-Liss, Inc.

  6. Spatial distribution of superconducting and charge-density-wave order parameters in cuprates and its influence on the quasiparticle tunnel current (Review Article)

    Science.gov (United States)

    Gabovich, Alexander M.; Voitenko, Alexander I.

    2016-10-01

    The state of the art concerning tunnel measurements of energy gaps in cuprate oxides has been analyzed. A detailed review of the relevant literature is made, and original results calculated for the quasiparticle tunnel current J(V) between a metallic tip and a disordered d-wave superconductor partially gapped by charge density waves (CDWs) are reported, because it is this model of high-temperature superconductors that becomes popular owing to recent experiments in which CDWs were observed directly. The current was calculated suggesting the scatter of both the superconducting and CDW order parameters due to the samples' intrinsic inhomogeneity. It was shown that peculiarities in the current-voltage characteristics inherent to the case of homogeneous superconducting material are severely smeared, and the CDW-related features transform into experimentally observed peak-dip-hump structures. Theoretical results were used to fit data measured for YBa2Cu3O7-δ and Bi2Sr2CaCu2O8+δ. The fitting demonstrated a good qualitative agreement between the experiment and model calculations. The analysis of the energy gaps in high-Tc superconductors is important both per se and as a tool to uncover the nature of superconductivity in cuprates not elucidated so far despite of much theoretical effort and experimental progress.

  7. The market viability of nuclear hydrogen technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Botterud, A.; Conzelmann, G.; Petri, M. C.; Yildiz, B.

    2007-04-06

    The Department of Energy Office of Nuclear Energy is supporting system studies to gain a better understanding of nuclear power's potential role in a hydrogen economy and what hydrogen production technologies show the most promise. This assessment includes identifying commercial hydrogen applications and their requirements, comparing the characteristics of nuclear hydrogen systems to those market requirements, evaluating nuclear hydrogen configuration options within a given market, and identifying the key drivers and thresholds for market viability of nuclear hydrogen options. One of the objectives of the current analysis phase is to determine how nuclear hydrogen technologies could evolve under a number of different futures. The outputs of our work will eventually be used in a larger hydrogen infrastructure and market analysis conducted for DOE-EE using a system-level market simulation tool now underway. This report expands on our previous work by moving beyond simple levelized cost calculations and looking at profitability, risk, and uncertainty from an investor's perspective. We analyze a number of technologies and quantify the value of certain technology and operating characteristics. Our model to assess the profitability of the above technologies is based on Real Options Theory and calculates the discounted profits from investing in each of the production facilities. We use Monte-Carlo simulations to represent the uncertainty in hydrogen and electricity prices. The model computes both the expected value and the distribution of discounted profits from a production plant. We also quantify the value of the option to switch between hydrogen and electricity production in order to maximize investor profits. Uncertainty in electricity and hydrogen prices can be represented with two different stochastic processes: Geometric Brownian Motion (GBM) and Mean Reversion (MR). Our analysis finds that the flexibility to switch between hydrogen and electricity leads

  8. Combustion characteristics of subsonic hydrogen jet diffusion flame

    Energy Technology Data Exchange (ETDEWEB)

    Torii, S. [Kumamoto Univ., Kumamoto City (Japan)

    2008-07-01

    This study investigated the split flame and re-ignition phenomenon of subsonic jet diffusion flames. The aim of the study was to characterize the underlying combustion characteristics of hydrogen micro-jet diffusion flames. The effects of nozzle diameter and rim thickness on flame re-ignition characteristics were examined. Hydrogen gas was used as a fuel during the experiments, and the flame was visualized suing the Schlieren technique in order to determine temperature and concentration measurements. The experimental apparatus consisted of a fuel nozzle, a fuel supply system, a stagnation pressure measuring device, a high-speed camera, and an image-processing system. The study showed that re-ignition phenomenon occurred in certain region of the nozzle, a small flamelet was located in the vicinity of the nozzle rim after the blowout of the main flame occurred. Further increases in mass flow rates then caused the flamelet to become extinguished. The study demonstrated that intermittence of the flame re-ignition depended on fuel mass flow rates. Rim thickness did not influence mass flow rates at the onset or at the end of the re-ignition phenomenon. It was concluded that rim thickness had a significant influence on the flamelet formed near the nozzle rim. Increases in height differences of the rim extended flame blowouts and alleviated flame lift-off behaviour. 10 refs., 9 figs.

  9. The evaluation of hydrogen peroxide bleaching of Gonometa ...

    African Journals Online (AJOL)

    The effect of hydrogen peroxide bleaching on Gonometa postica silk and the influence that temperature, pH and time duration had on hydrogen peroxide release , colour change, breaking load and stiffness were determined. The best bleaching (81 delta E) of the Gonometa postica silk fabric was obtained with 60 minutes ...

  10. INTEGRATED HYDROGEN STORAGE SYSTEM MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, B

    2007-11-16

    Hydrogen storage is recognized as a key technical hurdle that must be overcome for the realization of hydrogen powered vehicles. Metal hydrides and their doped variants have shown great promise as a storage material and significant advances have been made with this technology. In any practical storage system the rate of H2 uptake will be governed by all processes that affect the rate of mass transport through the bed and into the particles. These coupled processes include heat and mass transfer as well as chemical kinetics and equilibrium. However, with few exceptions, studies of metal hydrides have focused primarily on fundamental properties associated with hydrogen storage capacity and kinetics. A full understanding of the complex interplay of physical processes that occur during the charging and discharging of a practical storage system requires models that integrate the salient phenomena. For example, in the case of sodium alanate, the size of NaAlH4 crystals is on the order of 300nm and the size of polycrystalline particles may be approximately 10 times larger ({approx}3,000nm). For the bed volume to be as small as possible, it is necessary to densely pack the hydride particles. Even so, in packed beds composed of NaAlH{sub 4} particles alone, it has been observed that the void fraction is still approximately 50-60%. Because of the large void fraction and particle to particle thermal contact resistance, the thermal conductivity of the hydride is very low, on the order of 0.2 W/m-{sup o}C, Gross, Majzoub, Thomas and Sandrock [2002]. The chemical reaction for hydrogen loading is exothermic. Based on the data in Gross [2003], on the order of 10{sup 8}J of heat of is released for the uptake of 5 kg of H{sub 2}2 and complete conversion of NaH to NaAlH{sub 4}. Since the hydride reaction transitions from hydrogen loading to discharge at elevated temperatures, it is essential to control the temperature of the bed. However, the low thermal conductivity of the hydride

  11. Adaptation to low body temperature influences pulmonary surfactant composition thereby increasing fluidity while maintaining appropriately ordered membrane structure and surface activity.

    Science.gov (United States)

    Suri, Lakshmi N M; McCaig, Lynda; Picardi, Maria V; Ospina, Olga L; Veldhuizen, Ruud A W; Staples, James F; Possmayer, Fred; Yao, Li-Juan; Perez-Gil, Jesus; Orgeig, Sandra

    2012-07-01

    The interfacial surface tension of the lung is regulated by phospholipid-rich pulmonary surfactant films. Small changes in temperature affect surfactant structure and function in vitro. We compared the compositional, thermodynamic and functional properties of surfactant from hibernating and summer-active 13-lined ground squirrels (Ictidomys tridecemlineatus) with porcine surfactant to understand structure-function relationships in surfactant membranes and films. Hibernating squirrels had more surfactant large aggregates with more fluid monounsaturated molecular species than summer-active animals. The latter had more unsaturated species than porcine surfactant. Cold-adapted surfactant membranes displayed gel-to-fluid transitions at lower phase transition temperatures with reduced enthalpy. Both hibernating and summer-active squirrel surfactants exhibited lower enthalpy than porcine surfactant. LAURDAN fluorescence and DPH anisotropy revealed that surfactant bilayers from both groups of squirrels possessed similar ordered phase characteristics at low temperatures. While ground squirrel surfactants functioned well during dynamic cycling at 3, 25, and 37 degrees C, porcine surfactant demonstrated poorer activity at 3 degrees C but was superior at 37 degrees C. Consequently the surfactant composition of ground squirrels confers a greater thermal flexibility relative to homeothermic mammals, while retaining tight lipid packing at low body temperatures. This may represent the most critical feature contributing to sustained stability of the respiratory interface at low lung volumes. Thus, while less effective than porcine surfactant at 37 degrees C, summer-active surfactant functions adequately at both 37 degrees C and 3 degrees C allowing these animals to enter hibernation. Here further compositional alterations occur which improve function at low temperatures by maintaining adequate stability at low lung volumes and when temperature increases during arousal from

  12. On the influence of the aliphatic linker on fabrication of highly ordered and orientated self-assembled monolayers of aromatic selenols on AU(111)

    KAUST Repository

    Azzam, Waleed

    2014-03-06

    Self-assembled monolayers (SAMs) formed by adsorption of 1,2-dibenzyldiselenide (DPMSe) and 1,2-diphenyldiselenide (DBSe) on Au(111) substrates at room temperature have been characterized using scanning tunnelling microscopy, X-ray photoelectron spectroscopy, infrared reflection absorption spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and low-energy electron diffraction. Upon adsorption, the Se-Se bonds in DPMSe and DBSe were cleaved on the gold surface to form phenylmethaneselenolate (PMSe) and benzeneselenolate (BSe) species, respectively. Although both PMSe and BSe molecular entities only differ in their structure (an additional methyl group in PMSe), the resulting monolayer films revealed noteworthy dissimilarities regarding their adlayer SAM structure and surface morphology. The molecular adlayer structure and orientation of PMSe and BSe species were found to vary significantly with the immersion time (IT). The resulting PMSe films were poorly organized, and the structure was described by a (4√3 × 2) rectangular unit cell for the SAMs prepared with 24 h of IT. Moreover, the PMSe-SAMs were found to be unstable upon exposure to air for a long time. Our results showed that exposure to air for 48 h results in the formation of small bright ad-islands, which have a height corresponding to that of a single atomic step on the Au(111). Contrary, BSe-SAMs exhibited densely packed and well-ordered monolayers, and two different structural phases were resolved at short and long ITs. The most densely packed structure was obtained for SAMs prepared with very short ITs (10 min). Upon increasing the IT, the SAMs exhibited structural changes to a lower density of molecular packing structure. The spectroscopic data also confirmed this structural transformation by suggesting an upright orientation for BSe-SAMs prepared after short ITs and strongly inclined adsorption geometry for SAMs prepared after long ITs. © 2014 American Chemical Society.

  13. Enhancing hydrogen spillover and storage

    Science.gov (United States)

    Yang, Ralph T [Ann Arbor, MI; Li, Yingwel [Ann Arbor, MI; Lachawiec, Jr., Anthony J.

    2011-05-31

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonification as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  14. Enhancing hydrogen spillover and storage

    Science.gov (United States)

    Yang, Ralph T; Li, Yingwei; Lachawiec, Jr., Anthony J

    2013-02-12

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonication as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  15. Metallic hydrogen: The most powerful rocket fuel yet to exist

    Energy Technology Data Exchange (ETDEWEB)

    Silvera, Isaac F [Lyman Laboratory of Physics, Harvard University, Cambridge MA 02138 (United States); Cole, John W, E-mail: silvera@physics.harvard.ed [NASA MSFC, Huntsville, AL 35801 (United States)

    2010-03-01

    Wigner and Huntington first predicted that pressures of order 25 GPa were required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator. We discuss the applications of metastable metallic hydrogen to rocketry. Metastable metallic hydrogen would be a very light-weight, low volume, powerful rocket propellant. One of the characteristics of a propellant is its specific impulse, I{sub sp}. Liquid (molecular) hydrogen-oxygen used in modern rockets has an Isp of {approx}460s; metallic hydrogen has a theoretical I{sub sp} of 1700s. Detailed analysis shows that such a fuel would allow single-stage rockets to enter into orbit or carry economical payloads to the moon. If pure metallic hydrogen is used as a propellant, the reaction chamber temperature is calculated to be greater than 6000 K, too high for currently known rocket engine materials. By diluting metallic hydrogen with liquid hydrogen or water, the reaction temperature can be reduced, yet there is still a significant performance improvement for the diluted mixture.

  16. Configuration and technology implications of potential nuclear hydrogen system applications.

    Energy Technology Data Exchange (ETDEWEB)

    Conzelmann, G.; Petri, M.; Forsberg, C.; Yildiz, B.; ORNL

    2005-11-05

    Nuclear technologies have important distinctions and potential advantages for large-scale generation of hydrogen for U.S. energy services. Nuclear hydrogen requires no imported fossil fuels, results in lower greenhouse-gas emissions and other pollutants, lends itself to large-scale production, and is sustainable. The technical uncertainties in nuclear hydrogen processes and the reactor technologies needed to enable these processes, as well waste, proliferation, and economic issues must be successfully addressed before nuclear energy can be a major contributor to the nation's energy future. In order to address technical issues in the time frame needed to provide optimized hydrogen production choices, the Nuclear Hydrogen Initiative (NHI) must examine a wide range of new technologies, make the best use of research funding, and make early decisions on which technology options to pursue. For these reasons, it is important that system integration studies be performed to help guide the decisions made in the NHI. In framing the scope of system integration analyses, there is a hierarchy of questions that should be addressed: What hydrogen markets will exist and what are their characteristics? Which markets are most consistent with nuclear hydrogen? What nuclear power and production process configurations are optimal? What requirements are placed on the nuclear hydrogen system? The intent of the NHI system studies is to gain a better understanding of nuclear power's potential role in a hydrogen economy and what hydrogen production technologies show the most promise. This work couples with system studies sponsored by DOE-EE and other agencies that provide a basis for evaluating and selecting future hydrogen production technologies. This assessment includes identifying commercial hydrogen applications and their requirements, comparing the characteristics of nuclear hydrogen systems to those market requirements, evaluating nuclear hydrogen configuration options

  17. Economy of bituminous coal hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    von Hochstetter, H.

    1944-05-11

    The influence of various factors on the production cost of (Janina) bituminous coal hydrogenation is analyzed briefly. The initial reckoning yielded a production cost of 188 marks per metric ton of gasoline and middle oils. The savings concomitant to changes of one percent in gasification, one percent in utilization of purified coal, one percent raising of space/time yield, one percent increase in throughput, one percent in coal concentration in the paste, and one percent in low temperature carbonization yield are listed. Factors affecting hydrogen consumption are listed in a table. Investigations showed the carbon-richest coal to produce a deviation in the effect of gasification upon the working costs by only 10 percent when compared with the Janina coal. Thus, the values listed were considered as guidelines for all kinds of bituminous coal. The calculations admitted the following conclusions: a maximum concentration of coal in the paste is desirable; one can assume a 2 percent reduction in the utilization with a 10 percent increase in throughput, as long as no changes in low temperature carbonization yield take place by changing the distribution in oil production; this configuration would change if the major concern were gas production instead of working costs, or if hydrogen production were the bottleneck. 1 table.

  18. Advanced Hydrogen Turbine Development

    Energy Technology Data Exchange (ETDEWEB)

    Joesph Fadok

    2008-01-01

    maximize plant output is needed in order to address the DOE turbine goal for 20-30% reduction of combined cycle cost from the baseline. A customer advisory board was instituted during Phase 1 to obtain important feedback regarding the future direction of the project. he technologies being developed for the Hydrogen Turbine will also be utilized, as appropriate, in the 2010 time frame engine and the FutureGen Plant. These new technologies and concepts also have the potential to accelerate commercialization of advanced coal-based IGCC plants in the U. S. and around the world, thereby reducing emissions, water use, solid waste production and dependence on scarce, expensive and insecure foreign energy supplies. Technology developments accomplished in Phase 1 provide a solid foundation for ensuring successful completion in Phase 2 and providing that the challenging program goals will be achieved.

  19. Hydrogen and fuel cells: the preparation is following; Hydrogene et piles a combustible: la gestation se poursuit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The first applications of the fuel cells for the public are announced for 2007 in the portable domain (computers, phones...). Some technological locks remain to overcome in order to decrease the the hydrogen and cells production costs and to improve their longevity, especially for the automotive sector. The author discusses the static and the moving applications, the embedded applications, the platinum and the catalyzers, the hydrogen storage, the robotization and the hydrogen production. (A.L.B.)

  20. Topics in atomic hydrogen standard research and applications

    Science.gov (United States)

    Peters, H. E.

    1971-01-01

    Hydrogen maser based frequency and time standards have been in continuous use at NASA tracking stations since February 1970, while laboratory work at Goddard has continued in the further development and improvement of hydrogen masers. Concurrently, experimental work has been in progress with a new frequency standard based upon the hydrogen atom using the molecular beam magnetic resonance method. Much of the hydrogen maser technology is directly applicable to the new hydrogen beam standard, and calculations based upon realistic data indicate that the accuracy potential of the hydrogen atomic beam exceeds that of either the cesium beam tube or the hydrogen maser, possibly by several orders of magnitude. In addition, with successful development, the hydrogen beam standard will have several other performance advantages over other devices, particularly exceptional stability and long continuous operating life. Experimental work with a new laboratory hydrogen beam device has recently resulted in the first resonance transition curves, measurements of relative state populations, beam intensities, etc. The most important aspects of both the hydrogen maser and the hydrogen beam work are covered.

  1. Hydrogen Storage Tank

    CERN Multimedia

    1983-01-01

    This huge stainless steel reservoir,placed near an end of the East Hall, was part of the safety equipment connected to the 2 Metre liquid hydrogen Bubble Chamber. It could store all the hydrogen in case of an emergency. The picture shows the start of its demolition.

  2. Metastable ultracondensed hydrogenous materials

    Science.gov (United States)

    Nellis, W. J.

    2017-12-01

    The primary purpose of this paper is to stimulate theoretical predictions of how to retain metastably hydrogenous materials made at high pressure P on release to ambient. Ultracondensed metallic hydrogen has been made at high pressures in the fluid and reported made probably in the solid. Because the long quest for metallic hydrogen is likely to be concluded in the relatively near future, a logical question is whether another research direction, comparable in scale to the quest for metallic H, will arise in high pressure research. One possibility is retention of metastable solid metallic hydrogen and other hydrogenous materials on release of dynamic and static high pressures P to ambient. If hydrogenous materials could be retained metastably on release, those materials would be a new class of materials for scientific investigations and technological applications. This paper is a review of the current situation with the synthesis of metallic hydrogen, potential technological applications of metastable metallic H and other hydrogenous materials at ambient, and general background of published experimental and theoretical work on what has been accomplished with metastable phases in the past and thus what might be accomplished in the future.

  3. Hydrogen evolution reaction catalyst

    Science.gov (United States)

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  4. Dark hydrogen fermentations

    NARCIS (Netherlands)

    Vrije, de G.J.; Claassen, P.A.M.

    2003-01-01

    The production of hydrogen is a ubiquitous, natural phenomenon under anoxic or anaerobic conditions. A wide variety of bacteria, in swamps, sewage, hot springs, the rumen of cattle etc. is able to convert organic matter to hydrogen, CO2 and metabolites like acetic acid, lactate, ethanol and alanine.

  5. Influence of hydrogen treatment on SCR catalysts

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    reduction (SCR) process, i.e. the catalytic removal of NOx from the flue gas. A series of experiments was conducted to reveal the impact on the NO SCR activity of a industrial DeNOX catalyst (3%V2O5-7%WO3/TiO2) by treatment of H2. Standard conditions were treatment of the SCR catalyst for 60 min with three...

  6. Electrochemical Hydrogen Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Lipp, Ludwig [FuelCell Energy, Inc., Torrington, CT (United States)

    2016-01-21

    Conventional compressors have not been able to meet DOE targets for hydrogen refueling stations. They suffer from high capital cost, poor reliability and pose a risk of fuel contamination from lubricant oils. This project has significantly advanced the development of solid state hydrogen compressor technology for multiple applications. The project has achieved all of its major objectives. It has demonstrated capability of Electrochemical Hydrogen Compression (EHC) technology to potentially meet the DOE targets for small compressors for refueling sites. It has quantified EHC cell performance and durability, including single stage hydrogen compression from near-atmospheric pressure to 12,800 psi and operation of EHC for more than 22,000 hours. Capital cost of EHC was reduced by 60%, enabling a path to meeting the DOE cost targets for hydrogen compression, storage and delivery ($2.00-2.15/gge by 2020).

  7. Chlorific efficiency of coal hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Schappert, H.

    1942-10-20

    In studies on the calorific efficiency of coal hydrogenation, the efficiency for H/sub 2/ production was calculated to be 26%, the efficiency for hydrogenation was calculated to be 49%, and the efficiency of hydrogenation including H/sub 2/ production was 27.2%. The efficiency of hydrogenation plus hydrogen production was almost equal to the efficiency of hydrogen production alone, even though this was not expected because of the total energy calculated in the efficiency of hydrogenation proper. It was entirely possible, but did not affect computations, that the efficiency of one or the other components of hydrogenation process differed somewhat from 49%. The average efficiency for all cases was 49%. However, when hydrogen was not bought, but was produced--(efficiency of hydrogen production was 26%, not 100%-- then the total energy changed and the efficiency of hydrogen production and combination was not 26%, but 13%. This lower value explained the drop of hydrogenation efficiency to 27.2%.

  8. Nano cobalt oxides for photocatalytic hydrogen production

    KAUST Repository

    Mangrulkar, Priti A.

    2012-07-01

    Nano structured metal oxides including TiO 2, Co 3O 4 and Fe 3O 4 have been synthesized and evaluated for their photocatalytic activity for hydrogen generation. The photocatalytic activity of nano cobalt oxide was then compared with two other nano structured metal oxides namely TiO 2 and Fe 3O 4. The synthesized nano cobalt oxide was characterized thoroughly with respect to EDX and TEM. The yield of hydrogen was observed to be 900, 2000 and 8275 mmol h -1 g -1 of photocatalyst for TiO 2, Co 3O 4 and Fe 3O 4 respectively under visible light. It was observed that the hydrogen yield in case of nano cobalt oxide was more than twice to that of TiO 2 and the hydrogen yield of nano Fe 3O 4 was nearly four times as compared to nano Co 3O 4. The influence of various operating parameters in hydrogen generation by nano cobalt oxide was then studied in detail. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  9. Effects of Hydrogen on Fatigue Crack Growth and Stretch Zone of 0.08mass%C Low Carbon Steel Pipe

    OpenAIRE

    松岡,三郎; 堤, 紀子; 村上, 敬宜

    2008-01-01

    In order to investigate the influence of hydrogen and test frequency on fatigue crack growth rate, fatigue crack growth tests (R=0) were conducted on hydrogen charged and uncharged specimens of a 0.08mass%C low carbon steel pipe at test frequency 0.001-10Hz. Following the fatigue crack growth tests, the test for producing a stretch zone was carried out. Observing the morphologies of the striation and stretch zone on the fracture surface and slip bands on the specimen surface, it was revealed ...

  10. Regulation of the hydrogen metabolism in Methanothermobacter thermoautotrophicus

    NARCIS (Netherlands)

    Poorter, Linda Martine Isabel de

    2002-01-01

    Methanothermobacter thermoautotrophicus is an archaeon that reduces CO2 into methane with hydrogen as the electron donor. Under natural and laboratory conditions, hydrogen concentrations may vary over orders of magnitude. The organism has to adapt to these changes. In this thesis, the adaptation of

  11. Effect of heat treatments on the hydrogen embrittlement ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Delayed failure tests were carried out on hydrogen charged API X-65 grade line-pipe steel in as received (controlled rolled), normalized, and quenched and tempered conditions. The resistance to hydrogen embrittlement was found in the order of controlled rolled > quenched and tempered > normalized. The frac-.

  12. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.; Bell, C.M.; Chow, P.; Louie, J.; Mohr, J.M.; Peinemann, K.V.; Pinnau, I.; Wijmans, J.G.; Gottschlich, D.E.; Roberts, D.L.

    1990-10-01

    The production of hydrogen from synthesis gas made by gasification of coal is expensive. The separation of hydrogen from synthesis gas is a major cost element in the total process. In this report we describe the results of a program aimed at the development of membranes and membrane modules for the separation and purification of hydrogen from synthesis gas. The performance properties of the developed membranes were used in an economic evaluation of membrane gas separation systems in the coal gasification process. Membranes tested were polyetherimide and a polyamide copolymer. The work began with an examination of the chemical separations required to produce hydrogen from synthesis gas, identification of three specific separations where membranes might be applicable. A range of membrane fabrication techniques and module configurations were investigated to optimize the separation properties of the membrane materials. Parametric data obtained were used to develop the economic comparison of processes incorporating membranes with a base-case system without membranes. The computer calculations for the economic analysis were designed and executed. Finally, we briefly investigated alternative methods of performing the three separations in the production of hydrogen from synthesis gas. The three potential opportunities for membranes in the production of hydrogen from synthesis gas are: (1) separation of hydrogen from nitrogen as the final separation in a air-blown or oxygen-enriched air-blown gasification process, (2) separation of hydrogen from carbon dioxide and hydrogen sulfide to reduce or eliminate the conventional ethanolamine acid gas removal unit, and (3) separation of hydrogen and/or carbon dioxide form carbon monoxide prior to the shift reactor to influence the shift reaction. 28 refs., 54 figs., 40 tabs.

  13. Influence of the content of Cr in diffusive transport parameters and trapping of hydrogen in Fe alloys; Influencia del contenido de Cr en los parametros de transporte difusivos y de trapping de hidrogeno en aleaciones de Fe

    Energy Technology Data Exchange (ETDEWEB)

    Penalva, I.; Alberro, G.; Orduna, I.; Legarda, F.; Vila, R.; Ortiz, C. J.

    2013-07-01

    The materials candidates to be part of a fusion reactor must characterize properly to carry out the correct selection of the same. In this sense, the interaction of the isotopes of hydrogen with materials Such It is essential, since the transport parameters will Affect the inventory of hydrogen in the reactor Retained and, in Addition, of These components isotopes permeation through structural materials can Affect areas of human.

  14. Microwave plasma for hydrogen production from liquids

    Directory of Open Access Journals (Sweden)

    Czylkowski Dariusz

    2016-06-01

    Full Text Available The hydrogen production by conversion of liquid compounds containing hydrogen was investigated experimentally. The waveguide-supplied metal cylinder-based microwave plasma source (MPS operated at frequency of 915 MHz at atmospheric pressure was used. The decomposition of ethanol, isopropanol and kerosene was performed employing plasma dry reforming process. The liquid was introduced into the plasma in the form of vapour. The amount of vapour ranged from 0.4 to 2.4 kg/h. Carbon dioxide with the flow rate ranged from 1200 to 2700 NL/h was used as a working gas. The absorbed microwave power was up to 6 kW. The effect of absorbed microwave power, liquid composition, liquid flow rate and working gas fl ow rate was analysed. All these parameters have a clear influence on the hydrogen production efficiency, which was described with such parameters as the hydrogen production rate [NL(H2/h] and the energy yield of hydrogen production [NL(H2/kWh]. The best achieved experimental results showed that the hydrogen production rate was up to 1116 NL(H2/h and the energy yield was 223 NL(H2 per kWh of absorbed microwave energy. The results were obtained in the case of isopropanol dry reforming. The presented catalyst-free microwave plasma method can be adapted for hydrogen production not only from ethanol, isopropanol and kerosene, but also from different other liquid compounds containing hydrogen, like gasoline, heavy oils and biofuels.

  15. HYDROGEN INDUCED CRACKING IN MICROALLOYED STEELS

    Directory of Open Access Journals (Sweden)

    Duberney Hincapie-Ladino

    2015-03-01

    Full Text Available The need for microalloyed steels resistant to harsh environments in oil and gas fields, such as pre-salt which contain considerable amounts of hydrogen sulfide (H2 S and carbon dioxide (CO2 , requires that all sectors involved in petroleum industry know the factors that influence the processes of corrosion and failures by hydrogen in pipelines and components fabricated with microalloyed steels. This text was prepared from a collection of selected publications and research done at the Electrochemical Processes Laboratory of Metallurgical and Materials Engineering Department, Polytechnic School, São Paulo University. This document does not intend to be a complete or exhaustive review of the literature, but rather to address the main scientific and technological factors associated with failures by hydrogen in the presence of wet hydrogen sulfide (H2 S, particularly, when related to the Hydrogen Induced Cracking (HIC phenomenon. This complex phenomenon that involves several successive stages, HIC phenomena were discussed in terms of environmental and metallurgical variables. The HIC starts with the process of corrosion of steel, therefore must be considered the corrosive media (H2 S presence effect. Moreover, it is necessary to know the interactions of compounds present in the electrolyte with the metal surface, and how they affect the hydrogen adsorption and absorption into steel. The following stages are hydrogen diffusion, trapping and metal cracking, directly related to the chemical composition and the microstructure, factors that depend strongly on the manufacture of steel. The purpose of this paper is to provide the scientific information about the failures caused by hydrogen and challenge for the Oil and Gas Pipeline Industry.

  16. Catalytic hydrogen peroxide decomposition La1-xSrxCoO3-δ perovskite oxides

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2005-01-01

    Lanthanide perovskite oxides are mentioned as material for hydrogen peroxide sensor because they can catalytically decompose hydrogen peroxide in an aqueous medium. The catalytic properties of these perovskite oxides to hydrogen peroxide are suggested due to their oxygen vacancies influenced by the

  17. Exceptional Optoelectronic Properties of Hydrogenated Bilayer Silicene

    Directory of Open Access Journals (Sweden)

    Bing Huang

    2014-05-01

    Full Text Available Silicon is arguably the best electronic material, but it is not a good optoelectronic material. By employing first-principles calculations and the cluster-expansion approach, we discover that hydrogenated bilayer silicene (BS shows promising potential as a new kind of optoelectronic material. Most significantly, hydrogenation converts the intrinsic BS, a strongly indirect semiconductor, into a direct-gap semiconductor with a widely tunable band gap. At low hydrogen concentrations, four ground states of single- and double-sided hydrogenated BS are characterized by dipole-allowed direct (or quasidirect band gaps in the desirable range from 1 to 1.5 eV, suitable for solar applications. At high hydrogen concentrations, three well-ordered double-sided hydrogenated BS structures exhibit direct (or quasidirect band gaps in the color range of red, green, and blue, affording white light-emitting diodes. Our findings open opportunities to search for new silicon-based light-absorption and light-emitting materials for earth-abundant, high-efficiency, optoelectronic applications.

  18. Hydrogen engine performance analysis. First annual report

    Energy Technology Data Exchange (ETDEWEB)

    Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.

    1978-08-01

    Many problems associated with the design and development of hydrogen-air breathing internal combustion engines for automotive applications have been identified by various domestic and foreign researchers. This project addresses the problems identified in the literature, seeks to evaluate potential solutions to these problems, and will obtain and document a design data-base convering the performance, operational and emissions characteristics essential for making rational decisions regarding the selection and design of prototype hydrogen-fueled, airbreathing engines suitable for manufacture for general automotive use. Information is included on the operation, safety, emission, and cost characteristics of hydrogen engines, the selection of a test engine and testing facilities, and experimental results. Baseline data for throttled and unthrottled, carburetted, hydrogen engine configurations with and without exhaust gas recirculation and water injection are presented. In addition to basic data gathering concerning performance and emissions, the test program conducted was formulated to address in detail the two major problems that must be overcome if hydrogen-fueled engines are to become viable: flashback and comparatively high NO/sub x/ emissions at high loads. In addition, the results of other hydrogen engine investigators were adjusted, using accepted methods, in order to make comparisons with the results of the present study. The comparisons revealed no major conflicts. In fact, with a few exceptions, there was found to be very good agreement between the results of the various studies.

  19. Role of hydrogen in affecting the growth trend of CNT on micron spherical silica gel

    Science.gov (United States)

    Othman, R. N.; Ismadi, A. I.; Tawil, S. N.

    2017-04-01

    Grafting CNTs onto substrates such as fibres and microparticles offers an alternative approach to tackle the issues associated with dispersion in a composite matrix, as well as additional benefits (hybrid effects) provided by these dual-filler systems. One approach to obtain such hybrid systems is the direct growth of nanotubes on the supporting fibre or particles. Previous study has shown that the CNTs would grow on the silica microparticles with the morphology closely related to the operating conditions such as temperature and time. However, the role of hydrogen in affecting the tube’s morphology was not explored before. The particles were synthesized via chemical vapour deposition (CVD) method. Spherical silica gel with 40 - 75 μm diameter was used as the substrate. Toluene and ferrocene were used as the hydrocarbon and catalyst source, respectively. The reaction time was kept for four hours while the temperature was maintained at 850°C. The FESEM and TEM investigation proved that the flow hydrogen during reaction caused a tremendous difference in the outer diameter of the synthesized CNTs. Relatively thin CNT was observed under 50 ml/min of hydrogen flow compared to the particles synthesized without hydrogen. Raman spectroscopy of the CNTs revealed three bands; the disorder-induced D mode (˜1321 cm-1), the tangential G mode (˜1570 cm-1) and second order G‧ mode (˜2642 cm-1). Raman analysis shows that the synthesized CNTs exhibited all these peaks, confirming the existence of CNTs. As G peak is more intense than D peak for all samples synthesized under hydrogen flow, it can be concluded that CNTs synthesized is indeed of high quality. It can be confirmed that hydrogen plays an important role in influencing the morphology of the synthesized tubes.

  20. Volcanic Degassing of Hydrogen Compounds on Io

    Science.gov (United States)

    Zolotov, M. Yu.; Fegley, B., Jr.

    2000-01-01

    Thermodynamic calculations show that hydrogen, recently detected in Io's ionosphere by the Galileo spacecraft, can degas from high-temperature silicate magmas on Io in the form of H2O, H2S, HS, NaOH, H2, KOH, and HCl in order of decreasing abundance.

  1. Hydrogen Pellet-Rotating Plasma Interaction

    DEFF Research Database (Denmark)

    Jørgensen, L. W.; Sillesen, Alfred Hegaard; Øster, Flemming

    1977-01-01

    Spectroscopic measurements on the interaction between solid hydrogen pellets and rotating plasmas are reported. It was found that the light emitted is specific to the pellet material, and that the velocity of the ablated H-atoms is of the order of l0^4 m/s. The investigation was carried out...

  2. Quantum-electrodynamics corrections in pionic hydrogen

    NARCIS (Netherlands)

    Schlesser, S.; Le Bigot, E. -O.; Indelicato, P.; Pachucki, K.

    2011-01-01

    We investigate all pure quantum-electrodynamics corrections to the np --> 1s, n = 2-4 transition energies of pionic hydrogen larger than 1 meV, which requires an accurate evaluation of all relevant contributions up to order alpha 5. These values are needed to extract an accurate strong interaction

  3. The hydrogen highway

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, A. [Fuel Cells Canada, Vancouver, British Columbia (Canada)

    2004-07-01

    'Full text:' The Hydrogen Highway in British Columbia, Canada, is a coordinated, large-scale demonstration and deployment program aimed at accelerating the commercialization of hydrogen and fuel cell technologies and products. It will be a showcase for fuel cell vehicles, refuelling stations and stationary power systems leading up to the 2010 Olympic and Paralympic Winter Games in Whistler, BC. The Hydrogen Highway is designed to help address many of the challenges to commercialization identified in the Canadian Fuel Cell Commercialization Roadmap. The project will create an early adopter network of hydrogen and fuel cell microenvironments where technology developers and users can learn about the technical, economic, environmental and social impacts of products. The Hydrogen Highway will give the public and potential purchasers an opportunity to feel, touch and see the new technology, as well as provide the industry with a venue in which to develop industry standards and supply chains of materials and components. While demonstration and deployment programs are a recognized and necessary component in the process to commercialize hydrogen and fuel cell technologies, there is no handbook describing how it should be done. This paper will describe the history, objectives, project details and some of the challenges associated with establishing Canada's Hydrogen Highway. (author)

  4. Photoelectrochemical hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Rocheleau, R.; Misra, A.; Miller, E. [Univ. of Hawaii, Honolulu, HI (United States)

    1998-08-01

    A significant component of the US DOE Hydrogen Program is the development of a practical technology for the direct production of hydrogen using a renewable source of energy. High efficiency photoelectrochemical systems to produce hydrogen directly from water using sunlight as the energy source represent one of the technologies identified by DOE to meet this mission. Reactor modeling and experiments conducted at UH provide strong evidence that direct solar-to-hydrogen conversion efficiency greater than 10% can be expected using photoelectrodes fabricated from low-cost, multijunction (MJ) amorphous silicon solar cells. Solar-to-hydrogen conversion efficiencies as high as 7.8% have been achieved using a 10.3% efficient MJ amorphous silicon solar cell. Higher efficiency can be expected with the use of higher efficiency solar cells, further improvement of the thin film oxidation and reduction catalysts, and optimization of the solar cell for hydrogen production rather than electricity production. Hydrogen and oxygen catalysts developed under this project are very stable, exhibiting no measurable degradation in KOH after over 13,000 hours of operation. Additional research is needed to fully optimize the transparent, conducting coatings which will be needed for large area integrated arrays. To date, the best protection has been afforded by wide bandgap amorphous silicon carbide films.

  5. A green hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Clark, W.W. II [Clark Communications, Beverly Hills, CA (United States). Green Hydrogen Scientific Advisory Committee; Rifkin, J. [The Foundation on Economic Trends (United States)

    2006-11-15

    This paper is the result of over a dozen scholars and practitioners who strongly felt that a hydrogen economy and hence the future is closer than some American politicians and bureaucrats state. Moreover, when seen internationally, there is strong evidence, the most recent and obvious ones are the proliferation of hybrid vehicles, that for any nation-state to be energy independent it must seek a renewable or green hydrogen future in the near term. The State of California has once again taken the lead in this effort for both an energy-independent future and one linked strongly to the hydrogen economy. Then why a hydrogen economy in the first instance? The fact is that hydrogen most likely will not be used for refueling of vehicles in the near term. The number of vehicles to make hydrogen commercially viable will not be in the mass market by almost all estimates until 2010. However, it is less than a decade away. The time frame is NOT 30-40 years as some argue. The hydrogen economy needs trained people, new ventures and public-private partnerships now. The paper points out how the concerns of today, including higher costs and technologies under development, can be turned into opportunities for both the public and private sectors. It was not too long ago that the size of a mobile phone was that of a briefcase, and then almost 10 years ago, the size of a shoe box. Today, they are not only the size of a man's wallet but also often given away free to consumers who subscribe or contract for wireless services. While hydrogen may not follow this technological commercialization exactly, it certainly will be on a parallel path. International events and local or regional security dictate that the time for a hydrogen must be close at hand. (author)

  6. Photobiological hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Seibert, M; Lien, S; Weaver, P F

    1979-01-01

    Hydrogen production by phototrophic organisms, which has been known since the 1930's, occurs at the expense of light energy and electron-donating substrates. Three classes of organisms, namely, photosynthetic bacteria, cyanobacteria, and algae carry out this function. The primary hydrogen-producing enzyme systems, hydrogenase and nitrogenase, will be discussed along with the manner in which they couple to light-driven electron transport. In addition, the feasibility of using in vivo and in vitro photobiological hydrogen producing systems in future solar energy conversion applications will be examined.

  7. Photobiological hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Seibert, M.; Lien, S.; Weaver, P.F.

    1979-01-01

    Hydrogen production by phototrophic organisms, which has been known since the 1930's, occurs at the expense of light energy and electron-donating substrates. Three classes of organisms, namely, photosynthetic bacteria, cyanobacteria, and algae carry out this function. The primary hydrogen-producing enzyme systems, hydrogenase and nitrogenase, will be discussed along with the manner in which they couple to light-driven electron transport. In addition, the feasibility of using in vivo and in vitro photobiological hydrogen producing systems in future solar energy conversion applications will be examined.

  8. Biological hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J.R. [Univ. of California, Berkeley, CA (United States)

    1995-11-01

    Biological hydrogen production can be accomplished by either thermochemical (gasification) conversion of woody biomass and agricultural residues or by microbiological processes that yield hydrogen gas from organic wastes or water. Biomass gasification is a well established technology; however, the synthesis gas produced, a mixture of CO and H{sub 2}, requires a shift reaction to convert the CO to H{sub 2}. Microbiological processes can carry out this reaction more efficiently than conventional catalysts, and may be more appropriate for the relatively small-scale of biomass gasification processes. Development of a microbial shift reaction may be a near-term practical application of microbial hydrogen production.

  9. Chromatographic hydrogen isotope separation

    Science.gov (United States)

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  10. Color Changing Hydrogen Sensors

    Science.gov (United States)

    Roberson, Luke B.; Williams, Martha; Captain, Janine E.; Mohajeri, Nahid; Raissi, Ali

    2015-01-01

    During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous

  11. National hydrogen energy roadmap

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2002-11-01

    This report was unveiled by Energy Secretary Spencer Abraham in November 2002 and provides a blueprint for the coordinated, long-term, public and private efforts required for hydrogen energy development. Based on the results of the government-industry National Hydrogen Energy Roadmap Workshop, held in Washington, DC on April 2-3, 2002, it displays the development of a roadmap for America's clean energy future and outlines the key barriers and needs to achieve the hydrogen vision goals defined in

  12. Density functional study of hydrogen bond formation between methanol and organic molecules containing Cl, F, NH2, OH, and COOH functional groups.

    Science.gov (United States)

    Kolev, Stefan K; St Petkov, Petko; Rangelov, Miroslav A; Vayssilov, Georgi N

    2011-12-08

    Various hydrogen-bonded complexes of methanol with different proton accepting and proton donating molecules containing Cl, F, NH(2), OH, OR, and COOH functional groups have been modeled using DFT with hybrid B3LYP and M05-2X functionals. The latter functional was found to provide more accurate estimates of the structural and thermodynamic parameters of the complexes of halides, amines, and alcohols. The characteristics of these complexes are influenced not only by the principle hydrogen bond of the methanol OH with the proton acceptor heteroatom, but also by additional hydrogen bonds of a C-H moiety with methanol oxygen as a proton acceptor. The contribution of the former hydrogen bond in the total binding enthalpy increases in the order chlorides hydrogen bond increases in the reverse order. A general correlation was found between the binding enthalpy of the complex and the electrostatic potential at the hydrogen center participating in the formation of the hydrogen bond. The calculated binding enthalpies of different complexes were used to clarify which functional groups can potentially form a hydrogen bond to the 2'-OH hydroxyl group in ribose, which is strong enough to block it from participation in the intramolecular catalytic activation of the peptide bond synthesis. Such blocking could result in inhibition of the protein biosynthesis in the living cell if the corresponding group is delivered as a part of a drug molecule in the vicinity of the active site in the ribosome. According to our results, such activity can be accomplished by secondary or tertiary amines, alkoxy groups, deprotonated carboxyl groups, and aliphatic fluorides, but not by the other modeled functional groups.

  13. Bio-ethanol steam reforming: Insights on the mechanism for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Benito, M.; Sanz, J.L.; Isabel, R.; Padilla, R.; Daza, L. [Instituto de Catalisis y Petroleoquimica (CSIC), Campus Cantoblanco, 28049 Madrid (Spain); Arjona, R. [Greencell (ABENGOA BIOENERGIA), Av. de la Buhaira 2, 41018 Sevilla (Spain)

    2005-10-10

    New catalysts for hydrogen production by steam reforming of bio-ethanol have been developed. Catalytic tests have been performed at laboratory scale, with the reaction conditions demanded in a real processor: i.e. ethanol and water feed, without a diluent gas. Catalyst ICP0503 has shown high activity and good resistance to carbon deposition. Reaction results show total conversion, high selectivity to hydrogen (70%), CO{sub 2}, CO and CH{sub 4} being the only by-products obtained. The reaction yields 4.25mol of hydrogen by mol of ethanol fed, close to the thermodynamic equilibrium prediction. The temperature influence on the catalytic activity for this catalyst has been studied. Conversion reaches 100% at temperature higher than 600{sup o}C. In the light of reaction results obtained, a reaction mechanism for ethanol steam reforming is proposed. Long-term reaction experiments have been performed in order to study the stability of the catalytic activity. The excellent stability of the catalyst ICP0503 indicates that the reformed stream could be fed directly to a high temperature fuel cell (MCFC, SOFC) without a further purification treatment. These facts suggest that ICP0503 is a good candidate to be implemented in a bio-ethanol processor for hydrogen production to feed a fuel cell. (author)

  14. Surface plasmon resonance hydrogen sensor based on metallic grating with high sensitivity.

    Science.gov (United States)

    Lin, Kaiqun; Lu, Yonghua; Chen, Junxue; Zheng, Rongsheng; Wang, Pei; Ming, Hai

    2008-11-10

    High sensitivity is obtained at larger resonant incident angle if negative diffraction order of metallic grating is used to excite the surface plasmon. A highly sensitive grating-based surface plasmon resonance (SPR) sensor is designed for the hydrogen detection. A thin palladium (Pd) film deposited on the grating surface is used as transducer. The influences of grating period and the thickness of Pd on the performance of sensor are investigated using rigorous coupled-wave analysis (RCWA) method. The sensitivity as well as the width of the SPR curves and reflective amplitude is considered simultaneously for designing the grating-based SPR hydrogen sensor, and a set of optimized structural parameters is presented. The performance of grating-based SPR sensor is also compared with that of conventional prism-based SPR sensor.

  15. Influence of fertilization, mulch color, early forcing, fruit order, planting date, shading, growing Environment, and genotype on the contents of selected phenolics in strawberry (Fragaria x ananassa Duch.) fruits.

    Science.gov (United States)

    Anttonen, Mikko J; Hoppula, Kalle I; Nestby, Rolf; Verheul, Michél J; Karjalainen, Reijo O

    2006-04-05

    The influence of agricultural practices (fertilization, mulch color, early forcing, and planting date), environment (light and growing area), cultivar, and fruit order on the selected phenolic content and antioxidant activity in strawberry (Fragaria x ananassa Duch.) fruits was studied. Three different levels of fertilization were given to plants in the fertilization experiment. The lowest fertilization level increased the contents of flavonols and ellagic acid from 19 to 57%. Between cultivars, up to 4-fold differences were found in the flavonol content, and it also varied according to growing environment. Planting date in glasshouse production was important for the phenolic content, and a statistically significant interaction was found between planting date and fruit order. Fruit order caused at highest 1.5-2.0-fold differences in the contents of phenolics. Interestingly, compared with other phenolics, anthocyanins were affected differently by many factors. Thus, the findings show that minor cultivation changes can increase the content of phenolics, especially in under-glass production where conditions can be easily manipulated.

  16. Proton structure in the hyperfine splitting of muonic hydrogen

    OpenAIRE

    Hagelstein, Franziska; Pascalutsa, Vladimir

    2015-01-01

    We present the leading-order prediction of baryon chiral perturbation theory for the proton polarizability contribution to the 2S hyperfine splitting in muonic hydrogen, and compare with the results of dispersive calculations.

  17. Hydrogen production for fuel cell by oxidative reforming of diesel surrogate: influence of ceria and/or lanthana over the activity of Pt/Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    M.C. Alvarez-Galvan; R.M. Navarro; F. Rosa; Y. Briceno; M.A. Ridao; J.L.G. Fierro [Instituto de Catalisis y Petroleoquimica (CSIC), Madrid (Spain)

    2008-09-15

    A series of Pt catalysts supported on Al{sub 2}O{sub 3} (Pt/A), Al{sub 2}O{sub 3}-CeO{sub 2} (Pt/A-C), Al{sub 2}O{sub 3}-La{sub 2}O{sub 3} (Pt/A-L) and Al{sub 2}O{sub 3}-La{sub 2}O{sub 3}-CeO{sub 2} (Pt/A-L-C) have been prepared and tested in the oxidative reforming of diesel surrogate with the aim of studying the influence of ceria and lanthana additives over the activity and stability toward hydrogen production for fuel cell application. Several characterization techniques, such as adsorption-desorption of N{sub 2}, X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed reduction, H{sub 2} chemisorption, and thermogravimetric analysis, have been used to define textural, structural, and surface properties of catalysts and to establish relationships with their behaviour in reaction. This physicochemical characterization has shown that lanthana inhibits the formation of {alpha} phase in alumina support and decreases ceria dispersion. Activity results show a better performance of ceria-loaded catalysts, being the Pt/A-C sample the system that offers higher H{sub 2} yields after 8 h of reaction. The greater H{sub 2} production for ceria-loaded catalysts, particularly in the case of the system Pt/A-C, is attributed to the Pt-Ce interaction that may change the electronic properties and/or the dispersion of active metal phase. Also, the Ce{sup III} form of Ce{sup IV}/Ce{sup III} redox pair enhances the adsorption of oxygen and water molecules, thus increasing the catalytic activity and also decreasing coke deposition over surface active Pt phases. Stability tests showed that catalysts in which Pt crystallites are deposited on the alumina substrate covered by a lanthana monolayer, give rise to an increase in stability toward H{sub 2} production. 48 refs., 10 figs., 3 tabs.

  18. Hydrogen Recovery System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Liquid hydrogen is used extensively by NASA to support cryogenic rocket testing. In addition, there are many commercial applications in which delivery and use of...

  19. Hydrogen Recovery System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Rocket test operations at NASA Stennis Space Center (SSC) result in substantial quantities of hydrogen gas that is flared from the facility and helium gas that is...

  20. Photoelectrochemical hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Rocheleau, R.E.; Miller, E.; Misra, A. [Univ. of Hawaii, Honolulu, HI (United States)

    1996-10-01

    The large-scale production of hydrogen utilizing energy provided by a renewable source to split water is one of the most ambitious long-term goals of the U.S. Department of Energy`s Hydrogen Program. One promising option to meet this goal is direct photoelectrolysis in which light absorbed by semiconductor-based photoelectrodes produces electrical power internally to split water into hydrogen and oxygen. Under this program, direct solar-to-chemical conversion efficiencies as high as 7.8 % have been demonstrated using low-cost, amorphous-silicon-based photoelectrodes. Detailed loss analysis models indicate that solar-to-chemical conversion greater than 10% can be achieved with amorphous-silicon-based structures optimized for hydrogen production. In this report, the authors describe the continuing progress in the development of thin-film catalytic/protective coatings, results of outdoor testing, and efforts to develop high efficiency, stable prototype systems.