bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of the Reactions of CH2(ã1A1) with CH3C2H, HCN, CO2, N2O and COS
Authors: Koch M. , Temps F. , Wagener R. , Wagner H. Gg. 
Published: July 2012

AbstractThe reactions of CH2(ã1A1) with CH3C2H, HCN, CO2, N2O and COS are investigated at room temperature. CH2(ã1A1) is generated by pulsed laser photolysis of CH2CO. Overall removal rate constants are derived from concentration profiles under first order reaction conditions using direct, time resolved LIF detection of CH2(ã1A1). The second order rate constants are found in units of 1013 cm2/mol s to be 24, 18, 2.0, 3.8 and 20, respectively. — The contributions of physical quenching to the removal of CH2(ã1A1) are determined by monitoring directly the formation of CH2(X̃3B1) with the LMR absorption technique. The branching ratios of collision induced intersystem crossing versus total consumption of 1CH2 are 0.24, 0.32, 0.67, 0.46 and 0.29 for the five reactants.
The Debye‐Hückel Theory for Hydrated Ions. I. Osmotic and Activity Coefficients of Binary Aqueous Solutions of Some 1 : 1 Electrolytes at 25°C
Authors: Schönert Hansjürgen 
Published: July 2012

AbstractA thermodynamic model of stepwise hydration of ions in aqueous solutions has been developed. It is applied to the activity and osmotic coefficients of the alkali halogenides at 25°C. The hydration at infinite dilution can be decomposed into ion specific contributions. Together with a distance of closest approach in the Debye‐Hückel term it is possible to describe the activity and osmotic coefficients within the experimental error limits up to 1 molal solutions.
The Debye‐Hückel Theory for Hydrated Ions. II. Osmotic and Activity Coefficients of Ternary Aqueous Solutions of Hydrogen and Alkali Halogenides at 25°C
Authors: Schönert Hansjürgen 
Published: July 2012

AbstractThe Debye‐Hückel theory, including a closest distance of approach between cations and anions, has been extended to ternary solutions of 1: 1 electrolytes. Together with a thermodynamic model of stepwise hydration this allows the calculation of the Gibbs energy of ternary solutions without any ternary mixing parameter. The agreement between theory and experiment is good up to 1 molal solutions.
Hydrogen Solubility in the Liquid Alloys Lithium‐Indium, Lithium‐Lead, and Lithium‐Tin
Authors: Schumacher Richard , Weiss Alarich 
Published: July 2012

AbstractMeasurements of the hydrogen solubility in liquid alloys of the binary systems Li—In, Li—Pb and Li—Sn are reported. A detailled description of the experimental procedure is given. Solubility data were recorded in the pressure range 150—20000 hPa at temperatures up to 1220 K. Alloy interactions with stainless steel containers and with oxygen impurities were investigated. The temperature and pressure dependence of the mole fraction xH of hydrogen atoms in the melt at low hydrogen concentration, where Sievert's law is valid, can be described by the following equation: ln(xH√105Pa/PH2) = ‐ A + B/T. The values of the constants are A = 8.17, B = 734 K (LiPb); A = 7.84, B = 1970 K (Li62Pb38); A = 7.42, B = 1200 K (LiIn); A = 7.67, B = 3300 K (Li62In38); A = 7.08, B = 600 K (Li57Sn43); A = 6.86, B = 830 K (Li62Sn38). Strong deviations from Sievert's law are observed for two alloys indicating alloy decomposition. The reduction of the excess entropy of dissolved hydrogen in the alloys compared to pure lithium is discussed in the frame of an electrostatic model.
Inverted Micelles in a Ternary System AOT‐Water‐Benzene as Studied by Small‐Angle Neutron Scattering
Authors: Gorski Nikolai , Ostanevich Yurii M. 
Published: July 2012

AbstractWe performed the small‐angle neutron scattering measurements on AOT/benzene micelles with and without the addition of water. The scattering cross sections were studied as a function of the contrast of a solvent (the scattering length density of mixtures of protonated and deuterated benzene). We found that the volume per single AOT molecule in the micelle increases considerably when a small amount of water is added to a solution of “dry” micelles. The aggregation numbers of the micelles in benzene were found to be smaller by ca. 50% than those reported for decane. The observed dependence of the radii of gyration on the solvent contrast agrees well with the common picture of the structure of inverted micelles even in the case of “dry” micelles.
Transport Properties of Liquids. VIII. Molar Volume and Selfdiffusion of Organic Liquids at Pressures up to 200 MPa
Authors: Polzin Bernd , Weiss Alarich 
Published: July 2012

AbstractThe molar volumes V̄ and the self diffusion coefficients D of 2,2,4‐Trimethylpentane (C6H12), 2,2‐Dimethylbutane (C6H14), 1,3,5‐Trimethylbenzene (C9H12), Pentafluorobenzonitrile (C6F5CN), Tetramethyltin (Sn(CH3)4), 1,2‐Dibromotetrafluoroethane (C2Br2F4), Cyclo‐hexane (C6H12), and Benzene (C6H6) were measured in the range 1 ⩽ P/MPa ⩽ 200, 263 ⩽ T/K ⩽ 368. V̄ = f(P, T) is parameterized by use of the Tait‐equation and D = f(P, T) is given in a rational form, too. The diffusion coefficients, measured by the NMR spin echo method, decrease by a factor ⩾ 2 at constant temperature if the pressure is raised from 0.1 to 200 MPa. In the binary liquid system [Sn(CH3)4] 1‐x[C6H12]x V̄ and D of both components were investigated. The melting points of C6F5CN and cyclohexane were studied in dependence of the applied pressure. — The results of the diffusion experiments are discussed in the frame of the Free Volume Theory which fails at high pressures and temperatures. A decrease of the effective molecular volume with increasing temperature is probably responsible for this effect. — The volumeter and the diffusion cell constructed for the physical experiments are described.
Does Quantum Mechanics Select Out Regularity and Local Mode Behaviour in Nonlinearly Coupled Vibrational Systems?
Authors: Yurtsever E. , Brickmann J. 
Published: July 2012

AbstractA two dimensional strongly nonharmonic vibrational system with nonlinear intermode coupling is studied both classically and quantum mechanically. The system was chosen such that there is a low lying transition (in energy) from a region where almost all trajectories move regularly to a region where chaotic dynamics strongly dominates. The corresponding quantum system is far away from the semiclassical limit. The eigenfunctions are calculated with high precision according to a linear variational scheme using conveniently chosen basis functions. It is the aim of this paper to check whether the prediction from semiclassical theory, namely that the measure of classically chaotic trajectories in phase space approaches the measure of irregular states in corresponding energy ranges, holds when the system is not close to the classical limit. It is also the aim to identify individual eigenfunctions with respect to regularity and to differentiate between local and normal vibrational states. It is found that there are quantitative and also qualitative differences between the quantum results and the semiclassical predictions. We found a relatively high amount of regularity in the quantum system for energies where almost all classical trajectories move chaotically. This high regularity is manifested via level spacing statistics as well as by a careful study of the nodal behaviour of the eigenfunctions. Another result was not expected from semiclassical predictions: Some of the wave functions are localized and irregular, a behaviour which was not observed in the corresponding classical system.
Surface Graininess and a New Model of Nonionic Micelle of Octaoxyethylene Alkyl Ether
Authors: Matsumoto Takayoshi 
Published: July 2012

AbstractSurface graininess and micelle size of n‐dodecyl (octaoxyethylene glycol) monoether C12H25(OCH2CH2)8OH in an isotropic liquid phase (L1 phase) and a hexagonal mesophase (H1 phase) of an aqueous colloid were investigated through light scattering and small angle X‐ray scattering (SAXS). The micelle is almost spherical and the micelle radius remains about 28–30 Å over a wide concentration range from the critical micelle concentration (ca. 4 · 10−5 g/ml) to 0.3 g/ml. The aggregation number is 70–80 and depends slightly on temperature. The specific inner surface Os of the spherical micelle is obtained from the tail portion (large angle region) in the SAXS curve. The value of Os of the micelle in the L1 phase is ca. 0.2 Å−1 and this value is approximately twice as large as that of a smooth sphere. A new micelle model is also proposed.
“Development of Advanced Noble Metal‐Alloy Electrocatalysts for Phosphoric Acid Fuel Cells (PAFC)”
Authors: Stonehart Paul 
Published: July 2012

AbstractIn the preparation of highly dispersed noble metal electrocatalysts, the technology is such that crystallites now can be routinely prepared with small dimensions so that 50% of the atom content resides at the particle surface. The crystallite diameters are of the order of 12 Angstrøm (1.2 nanometers). Operation of these materials, when applied to phosphoric acid fuel cells as electrocatalysts is, of course, critical. What is important is the realization that due to the high surface energies of these crystallites, they have properties that are unlike the properties of the bulk metals. Although this manufacturing achievement is very great, more recently there has been increased emphasis on preparing alloys of metals with platinum in order to increase the kinetic rate of reaction for the oxygen reduction.—For oxygen reduction, binary alloys of platinum with refractory metals such as vanadium showed higher activity, but the vanadium was rapidly leached out. Alloys with chromium and subsequently with the addition of cobalt to form ternary alloys have now exhibited greater resistance to degradation. These alloys are hard and resistant to sintering, until the alloying element is leached out, then crystallite growth is obtained.—More recently, process modifications to produce ordered alloys have shown stability for over 9000 hours in the hot phosphoric acid fuel cell environment, as have alloys of platinum with cobalt and/or chromium containing gallium additions. It is one theory that there is no catalytic enhancement for oxygen reduction due to these alloying elements, but the increased reactivity is due solely to leaching out of the alloying elements from the alloy surface to produce a microroughness in the platinum crystallite.—In the case of hydrogen oxidation, especially in the presence of electrocatalyst poisons such as carbon monoxide and hydrogen sulphide, alloys of platinum with palladium show greater tolerance to poisoning and greater stability against crystallite growth. Other alloys are now under development to lower the catalyst cost and increase the electrocatalyst performance. This work is coupled with developments of advanced theoretical models that are amenable to computer solution for the operation of gas‐diffusion electrodes to maximize both the catalyst utilization within the electrode structure, and within the cell stack.
Fuel Cells as a Power Source of Propulsion Systems
Authors: Straßer K. 
Published: July 2012

AbstractSince the midsixties Siemens has been pursuing the development of fuel cells. The development was concentrated on the alkaline H2/O2 fuel cell with circulating electrolyte and platinmetal‐free electrodes. By the modular and compact design it is relatively simple to adapt the FC‐system to the requirements of special applications. A propulsion system, in which the accumulator and the FC‐system are electrically connected in parallel, was tested for demonstration in a propulsion system of an electric van and a submarine. The design in principle and test results will be reported.
Hydrous Oxide Formation on Platinized Platinum Electrodes and its Relevance to Oxygen Gas Reduction
Authors: Burke L. D. , Casey J. K. 
Published: July 2012

AbstractSpontaneous formation of hydrous oxide species at a platinized platinum electrode, held at 0.85 V(RHE), in aqueous H2SO4 solution at 60°C was detected by an electrochemical technique. Such species are assumed to be a source of inhibition of oxygen gas reduction at fuel cell cathodes operating in aqueous media at potentials above ca. 0.6 (RHE); reaction in the latter case may be confined to less active sites where hydrous oxide formation occurs less readily. Reduction of oxygen in the oxide layer region was found to be time dependent and independent of rotation rate. The former effect was attributed to a surface restructuring process and the latter to the fact that oxygen gas was not involved in the rate‐determining stage of the reaction.
The State of MCFC Technology Development
Authors: Kishida Koji 
Published: July 2012

AbstractMolten Carbonate Fuel Cell (MCFC) technology development has become one of the highest priority R & D projects in the field of energy because of its outstanding energy conversion efficiency from various hydrocarbon fuels and coal derived gas to electricity.—This paper presents the state‐of‐the‐art of MCFC technology in Mitsubishi Electric Corporation (MELCO) and discusses the technical problems having been encountered and the countermeasures to overcome or to optimize them.—The fundamental issues are corrosion, creep and compatibility of the cell component materials. This paper presents an effective means of minimizing the anode creep, and optimizing the thickness of the anode, the cathode and the matrix. The principal subject discussed in this paper is the life of a MCFC stack, in other words what are the major life limiting factors and how to challenge to these factors.—Cathode (NiO) dissolution during cell operation has been a serious problem since many years ago. Additive elements into electrolyte and lower C02 partial pressure are the effective way to suppress dissolution. Electrolyte loss and migration phenomena cause a sizable imbalance in the electrolyte content in the individual cells in a stack. The countermeasures against this problem are studied.—The other subject handled in this paper is the progress of internal reforming (IR) stack development. A 3 KW direct‐IR stack and a 10 KW indirect‐IR stack are being operated and various testings are being performed in MELCO. The status of IR technology is briefly described.
NiO Cathode Dissolution and Long Term MCFC Operation
Authors: Veldhuis J. B. J. , Van Molen S. B. Der , Makkus R. C. , Broers G. H. J. 
Published: July 2012

AbstractThe lifetime of a molten carbonate fuel cell is significantly reduced by the slow dissolution of the state‐of‐the‐art nickel oxide cathode material. The dissolved Ni ions precipitate in the matrix.—The amount of nickel found in the matrix and the location of the precipitation zone observed in small size cell tests are reported. These cells were operated for various times, up to 20000 hours. An average dissolution rate of 4 μg/cm2 h was calculated. The precipitation zone moved linearly with the square root of time towards the anode. This may be due to changes in the matrix and electrode structure and, additionally, to the surface diffusion of the precipitated metallic nickel.—The results obtained are compared with a simple model describing the transport of nickel through the matrix and the location of the precipitation band. This model accounts for the diffusion, migration and the coupling of the dissolved species to the movement of the carbonate ions. The model calculations agree reasonably well with the experimental results.
Internal Reforming for Molten Carbonate Fuel Cells
Authors: Ledjeff K. , Rohrbach T. , Schauraberg G. 
Published: July 2012

AbstractMolten carbonate fuel cell systems can be operated with pure hydrogen or carbonaceous fuel gases, like natural gas. The use of natural gas is of advantage because of the present, widespread distribution network installed by the gas industry. The MCFC is not able to consume the methane directly, because the electrochemical reaction taking place at the anode needs hydrogen. There are various concepts for reforming in work and they can be devided into external, integrated and internal. The most promising are integrated and internal reformers, because they use the waste heat of the fuel cells for the endothermic reforming reaction. Thus, the efficiency of the system can be increased from about 50% to about 65%. Besides of the reforming concepts the paper will handle the thermodynamic background and experimental results achieved in our laboratory.
Ionic Contact Equilibria in Solids—Implications for Batteries and Sensors
Authors: Maier Joachim , Lauer Ute 
Published: July 2012

AbstractWe have been investigating the relevance of ionic space charge effects at surfaces and interfaces in multiphase and polycrystalline materials from both a theoretical and an experimental point of view. A brief review is given, which also includes the behaviour of the electronic minority species, as well as the qualitatively different situation in micro‐sized systems. A major part is devoted to the implications with respect to batteries and sensors: i) enhancement of the ionic conductivity of solid battery electrolytes due to internal interfaces; ii) impact of ionic profiles on the phase boundary reactions particularly in e.m.f. and conductivity sensors; iii) formulation of a new sensor principle.
Ceramic and Metallic Components for a Planar SOFC
Authors: Ivers‐Tiffée E. , Wersing W. , Schießl M. , Greiner H. 
Published: July 2012

AbstractWe present a planar cell design for Solid Oxide Fuel Cells (SOFC) which combines the ceramic materials of a solid electrolyte (Y‐stabilized ZrO2), cathode (LaSrMeO3 with Me : Mn, Co and Cr), and anode (Ni‐Cermet) with a metallic interconnection material, the so‐called metallic bipolar plate. This metallic component—which functions as a mechanically stabilizing frame, as well as gas distributor and electrical connector—possesses the advantages of much higher electrical and thermal conductivity when compared with the common ceramic interconnection material (LaCrO3). This allows the construction of cell stacks with increased power density (> 100 kW m3).
In‐Situ Infrared Spectroscopic Studies of Methanol Electrooxidation on Pt
Authors: Kunimatsu Keiji 
Published: July 2012

AbstractNature of the methanol adsorbate on platinum electrode and its role in methanol electrooxidation have been studied by in‐situ infrared spectroscopy.—The infrared adsorption intensities of linear CO(a) derived from CO and methanol respectively on a platinum electrode in 0.5 M sulfuric acid were determined as a function of the total adsorbate coverage.—It has been confirmed based on the quantitative comparison of the infrared absorption intensities that the linear CO(a) is the predominant surface species derived from methanol on a smooth platinum electrode in acidic media. However, presence of minor surface species besides the linear CO(a) has also been suggested for the coverages higher than 0.3.—The linear CO(a) acts as the so called catalysis poison for methanol electrooxidation, which has been confirmed by the following two observations; firstly oxidation of the linear CO(a) observed around 0.5 V is accompanied by a sharp increase of the methanol electrooxidation current, secondly rapid decrease of the methanol electrooxidation current observed while the electrode was held at 0.4 V is accompanied by a steady build up of the infrared absorption band of the linear CO(a).
The Interconversion of Adsorbed Methanol Fragments on Platinum at Cathodic Potentials
Authors: Christensen P. A. , Hamnett A. , Potter R. J. 
Published: July 2012

AbstractThe oxidation of methanol at a platinum electrode in neutral sulphate solution was investigated using in‐situ FTIR. Hitherto unreported interconversion between various adsorbed carbonyl species was observed at cathodic potentials, this conversion being driven by the formation of strongly adsorbed hydride.
Structural Concepts for Disordered Inorganic Solids. Modern NMR Approaches and Strategies. Invited Review
Authors: Eckert Hellmut 
Published: July 2012

AbstractMany technologically interesting materials properties are caused by intrinsic structural or dynamic disorder phenomena in solids. For this reason, the structural characterization of disordered states constitutes a central aspect of materials science. Within the past decade, nuclear magnetic resonance techniques have made increasingly significant and detailed contributions to this subject. The present review will portray some of the more common methods employed and discuss several important applications to problems in various inorganic materials areas.
Thermodynamic Analysis of Extraction of Mg(NO3)2, MnCl2 and NiCl2 by n‐Octanol at 298.15 K
Authors: Apelblat Alexander , Manzurola Emanuel 
Published: July 2012

AbstractPartition of Mg(NO3)2, MnCl2, NiCl2 and water between the aqueous phase and n‐octanol at 298.15 K is considered. Equilibrium distribution of salts is consistent with formation of Mg(NO3)2(H2O)5(ROH)5, MnCl2(H2O)14(ROH)7 and NiCl2(H2O)7(ROH)2 complexes in the alcoholic phase. Activities of n‐octanol were evaluated by a numerical integration of the Gibbs‐Duhem equation in ternary systems.
Liquid‐Liquid Equilibria in the Ternary Systems with Citric, Tartaric and Malic Acids and Aliphatic Alcohols
Authors: Apelblat Alexander , Glazer Sigal , Kost Ayala , Manzurola Emanuel 
Published: July 2012

AbstractExtraction equilibria in the citric acid‐water‐2‐pentanol, tartaric acid‐water‐1‐octanol, malic acid‐water‐isobutanol and malic acid‐water‐1‐pentanol systems are considered. Solubilities of 2‐butanol in succinic acid, 2‐pentanol and 1‐hexanol in citric acid aqueous solutions are also reported. Distribution of hydroxycarboxylic acids is expressed in terms of H3Cit (H2O)6(ROH)3 and H2Tar (ROH)3 formation in the alcoholic phase. The equilibrium constants of these complexes are 0.58 for citric acid and 0.052 for tartaric acid. The activities of components in ternary systems were evaluated using the mass‐action and Gibbs‐Duhem equations.
Dipolar Characteristics of the Imine‐Group and its Hydrogen Bonds. A Quantum‐Chemical and Experimental Approach
Authors: Peeters D. , Huyskens P. , Nelis K. 
Published: July 2012

AbstractThe dipole moments of two aliphatic imines and their hydrogen bonded phenol complexes were determined experimentally. A value of 1.63D was found for isopropyl, N isopropyl imine and 1.60 D for tertio butyl, N isobutyl imine. Their complexes with phenol, 3,5 dichloro‐ and para nitro phenol are respectively of 3.45, 4.57 and 6.99 D for the first and 3.69, 4.67 and 7.10 D for the second. This experimental study was completed by a theoretical study of model imines and their complexes with watermethanol and formic acid. The theoretical results explain through structural and electronic arguments the variation of the dipole moments. They furnish also values of the angles which are indispensable for the discussion of experimental dipole increments. The dipole increments obtained show clearly the strength of the H‐bond obtained with imine bases as well as its sensibility to the strength of the associated acid.
Ion‐Solvent Interactions of Silver (I) Salts in Water‐DMSO Mixtures from Conductance Measurements
Authors: Sreekumar T. K. , Janardhanan S. , Kalidas C. 
Published: July 2012

AbstractThe conductances of silver (I) perchlorate, nitrate and bromate have been determined in water‐dimethylsulfoxide (DMSO) mixtures at 30°C over the complete range of solvent compositions. The data were analyzed by the 1980 Fuoss equation and the limiting molar conductances (<Λ0) and association constants (KA) of the salts were evaluated at all compositions. The Λ0 values have been split into their ionic values and the ionic Walden products of all the ions were calculated using the transference number data derived from a concentration cell with transference. The initial increase of the Walden product of silver ion up to 20 wt% DMSO and its subsequent decrease beyond this composition with addition of DMSO, indicates that it is preferentially solvated by water at high compositions of water and subsequently by DMSO. For anions, the Walden products vary in a complex manner and seem to be strongly influenced by solvent‐solvent interactions.