bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Spectroscopic Studies of Thin Polyaniline Films
Authors: Korzeniewski Carol , Seeger David M. 
Published: March 2011

AbstractThe electrochemistry of polyaniline depends upon the pH of the deposition solution and the nature of the anion present during deposition. When the pH of the deposition solution is below 1.0, the response is typical of the para-substituted phenyleneamine structure. When the pH of the deposition solution is greater than 1.0, an additional voltammetric wave appears, and the response is a function of the dopant anion. This report presents results of an in situ infrared spectroscopic study aimed at elucidating structural features which determine the anion dependent voltammetric response.
ESR Investigation of Copper Ion Mobility in PEO:Cu(CF3SO3)2 Complexes
Authors: Adamic K.J. , Greenbaum S.G. , Panero S. , Prosperi P. , Scrosati B. 
Published: March 2011

AbstractPolymer electrolytes consisting of poly(ethylene oxide) (PEO) complexed with Cu(CF3SO3)2 have been studied by differential scanning calorimetry (DSC), electron spin resonance (ESR) and ionic conductivity measurements. Although motional effects on the ESR spectra are apparent, the present results cannot distinguish between long range Cu2+ transport or the motion of copper ions attached to polyether segments.
Manganese Dioxides: Structural Model and In-Situ Neutron Powder Diffraction Investigation of Thermal Annealing and Electrochemical Reduction
Authors: Ripert M. , Pannetier J. , Chabre Y. , Poinsignon C. 
Published: March 2011

AbstractStarting from the seminal work of De Wolff [1], we have developed a structural description, based on two kinds of defects, which accounts for the scattering function of all γand ε-MnO2. Using numerical simulation results, we propose simple methods to estimate the parameters which characterize real manganese dioxide samples. Real time neutron powder diffraction has been used to investigate in situ the transformations undergone by γ-MnO2 during thermal annealing and electrochemical reduction in alkaline solutions. We have found that thermally induced transformation from MnO2 to ∝-Mn2O3 can involve up to seven different steps and that electrochemical reduction of γ-MnO2 in KOD electrolyte proceeds through three stages, the final one leading in most cases to a breakdown of the initial crystal lattice.
Transport Properties of the Intercalated Layered Cathode Materials : LiXMo2O4.
Authors: Colson S. , Tarascon J.M. , Szu S. , Klein L.C. 
Published: March 2011

AbstractThe mixed conducting LixMO2O4 system was shown to exhibit a high energy density (530Wh/kg) and average voltage (3.1V), suggesting that it would be a good candidate for a cathode in a Li-anode secondary battery. The transport properties of these oxide materials were then investigated by solid state 7Li NMR, dc and ac electrical measurements. The following phases are emphasized in this study: Li1.3MO204, Li2MO204, and the hydrated phase Li0.5 (H20) 1.3MO2O4.
Layered V205 Xerogels: Host-Guest Chemistry and Conductive-Polymers.
Authors: Wu Chun-Guey , Kanatzidis Mercouri G. 
Published: March 2011

AbstractThe properties of vanadium oxide xerogels are reviewed with respect to guest-host chemistry, redox chemistry and electrical charge transport. The insertion chemistry of several conductive and insulating polymers and alkali ions. The physical properties of the resulting materials is discussed.
Electrical Conductivity of TTF-Hydrogen Uranyl Phosphate Composite
Authors: Moreno-Real L. , Pozas-Tormo R. , Bruque S. , Martinez-Lara M. , Ramos-Barrado J. 
Published: March 2011

AbstractH3OUO2PO4.3H2O (HUP) undergoes intercalative reaction with tetrathiafulvalene (TTF) given a black solid with the next composition: (TTF)U02P04.0.6H2O. The electrical conductivity fall from 2.40.10−6Ω−1cm−1(363K) to 8.8.10−8Ω−1cm−1(473K).
Local and Translational Motion of the 6Li and 7Li Ions in the Li3Sc2(PO4)3 and Li3In2(PO4)3 Compounds
Authors: Pronin Igor S. , Sigaryov Sergei E. , Vashman Andrei A. 
Published: March 2011

AbstractBasing on impedance and NMR spectroscopy data it is shown that there are two types of lithium ion motion in the each polymorhic modification of the Li3 Sc2 (P04)3 and Li3 In2 (P04)3 solid electrolytes. First type is a translational motion of these ions which determines the a values, while the second one is Li ion motion within the lithium ion—ion pairs at the distance about the sum of two lithium ionic radii. Substitution of 7Li by 6Li leads to the mixed alkali effect—type behaviour of σ.
Neutron Diffraction Studies on the Structure and Conduction Mechanism in Al, Ga—DOPED Li4SiO4
Authors: Smith R.I. , West A.R. 
Published: March 2011

AbstractCrystallographic results on the Li4-3x(Al,Ga)xSiO4 solid solutions are reviewed. The six sets of sites available for Li+ ions fall into two groups. The ‘framework’ sites, which also contain the substitutional Al,Ga ions, appear to have little effect on conductivity. The ‘channel’sites contain varying amounts of Li+ ions and are responsible for the dramatic variations in conductivity with x. There is evidence for the presence of one—dimensional defects, comprising columns of ordered Li+ ions, in both the framework and channel sites. The relative numbers of these linear defects has a large bearing on the solid solution mechanism in the framework sites and their occurrence in the channel sites may be responsible for the low conductivity in stoichiometric Li4SiO4.
Characterization of Indium Oxide for the Use as a Counter-Electrode in an Electrochromic Device
Authors: Yu Phillip C. , Haas Terry E. , Goldner Ronald B. , Cogan Stuart F. 
Published: March 2011

AbstractThin films of indium oxide, In2O3 (4000 Å), deposited on commercially available In2O3: Sn (ITO)/glass by rf sputtering, have been examined for potential application as a counter-electrode material in an electrochromic device, based on their chemical, structural, and optical properties. Cyclic voltammetry experiments showed that mobile lithium ions can be inserted (chemical reduction) and removed (chemical oxidation) from the host structure of indium oxide. Coulometric titrations showed that the films exhibited a hysteresis behavior for the injection and removal of lithium ions in LixIn2O3 (x=0-0.23). Structural investigation of the indium oxide films, utilizing electron diffraction techniques, indicated that they were crystalline with a crystallite size of 175 Å, in agreement with x-ray diffraction results. Differences in optical transmission between the lithiated and delithiated thin films were no more than 5% in the visible/near-infrared regions of the spectrum.
Synthesis, Structure, and Ionic Conductivity of K3NdSi6O15
Authors: Haile Sossina M. , Siegrist Theo , Laudise Robert A. , Wuensch Bernhardt J. 
Published: March 2011

AbstractA structure earlier reported for K3NdSi6O15 suggests the possibility for fast—ion conduction by virtue of K+ ions which not only reside in connected channels, but which also display very large thermal vibration amplitudes. No properties of the phase had heretofore been examined. Crystals up to 2mm inlength have been synthesized under a variety of hydrothermal conditions. Refinement of the structure with single crystal x-ray data to a residual of 8.3% confirms the composition and structure of our crystals and reveals a very high thermal vibration amplitude along c for K+ ions which reside in interconnected [001] channels.A reversible phase transformation has been discovered at 180ºC with a heat of transformation of 4J/g. Preliminary measurements of the conductivity of the high temperature phase yield a preexponential factor of 3.4/cm and an activation energy of 0.61ev along [001], indicating that this compound is not a particularly good fast—ion conductor.
Conductivity Mechanisms in Acceptor Doped KTaO3 Crystals
Authors: Scherban T. , Fu S.Q. , Nowick A.S. 
Published: March 2011

AbstractThe electrical conductivity of perovskite—structured KTaO3 crystals acceptor doped with Co, Cu or Fe was investigated after treatments in oxidizing and reducing atmospheres under both wet and dry conditions. Isotope effect measurements (using H2O vs. D2O) show that, after treatments in wet gases of low P(O2), all the crystals are primarily protonic conductors, through a process of proton hopping with an activation energy close to 0.84 eV. Electron hole conduction dominatesat high P(O2) in the case of Fe and Cu doping. For Co—doped crystals, the conductivity is independent of P(O2) up to 1 atm., indicating that ionic conduction predominates. There is no evidence of oxygen vacancy migration, leading to the conclusion that the activation energy for that process Is relatively high.
Mixed Ionic-Electronic Conduction in Pyrochlore Oxides
Authors: Spears M. , Kramer S. , Moon P.K. , Tuller H.L. 
Published: March 2011

AbstractThe transport properties of the pyrochlore solid solution Gd2(ZrxTil-x)2O7 are investigated to clarify the relationships between composition, structural disorder and ionic and electronic transport. The oxygen ion conductivity has been found to increase sharply with increasing Zr content, x, due to enhanced structural disorder, leading to intrinsic ionic conduction at large values ofx. In contrast, the n—type conductivity predominant at low x, decreases sharply above x=0.2. Defect chemical models are presented to account for the simultaneous contributions of both intrinsic and dopant induced disorder. These models are applied to the σ(T, PO2, dopant) data to extract key thermodynamic and transport parameters. The significance of these parameters and the potential application of these materials in electrochemical devices are discussed.
Jump Relaxation: Simple Equations, Relevant Functions, and Kohlrausch-Williams-Watts Behavior
Authors: Funke Klaus 
Published: March 2011

AbstractSolid electrolytes with structural disorder generally exhibit characteristic deviations from standard-theory spectra. The effect is known as “universal” dynamic response. In the jump-relaxation model, the phenomena are consistently explained in terms of the non-random hopping resulting from the repulsive Coulomb interaction among the mobile ions. In previous stages of the development of the model, the treatment required either crude approximations or extensive numerical calculations. Now. however, we are able to present, for the first time. simple analytic expressions for the relevant time correlation functions, derived from the rate equations of the model. In particular, the dependence of the ionic conductivity on frequency and temperature is now expressed by a simple equation. Furthermore, we recover the Kohlrausch-Williams- Watts behavior and find the KWW exponent. β. and the mismatch parameter of our model, α. to be identical. The validity of the KWW law is shown to be limited to the dispersive regime on the frequency and time scales.
Rare Earth Elements Behaviour During Alteration of Basaltic Glasses: Case of the Weathering of Icelandic Hyaloclastites
Authors: Daux V. , Crovisier J. L. , Petit J. C. 
Published: March 2011

ABSTRACTSubglacial basaltic glasses from Iceland have been studied in order to investigate REE behaviour during low-temperature weathering. As heavy elements accumulate in the hydrated superficial corrosion layer of borosilicate glasses, REE are found to be enriched in the natural corrosion layer of basaltic glasses (palagonite). However, mass balance calculations performed for our natural samples evidenced that this enrichment is only relative: the corrosion process leads to absolute losses of elements including REE.
The Use of Partial-Replenishment Tests in Modeling the Leach behavior of Glasses
Authors: Barkatt Aa. , Olszowka S. A. , Sousanpour W. , Choudhury T. , Guo Y. , Barkatt Al. , Adiga R. 
Published: March 2011

ABSTRACTThe partial-replenishment test can be an important tool in exploring the long-term leach behavior of glasses. In order to demonstrate the use of partial-replenishment test data in modeling, experiments were conducted which show that after a relatively short period test results become largely independent of exchange interval and volume exchange fraction. The results can be characterized by the ratio between these two parameters, which corresponds to the residence time. Sampling of the leachates during a given exchange interval shows that leachate concentrations quickly recover following the exchange, and that this recovery can be satisfactorily described using a simple model based on first-order approach to equilibrium at the silica saturation level.
Dissolution Behaviour of Used Candu Fuel Under Disposal Conditions.
Authors: Tait J. C. , Stroes-Gascoyne S. , Hocking W. H. , Duclos A. M. , Porth R. J. , Wilkin D. L. 
Published: March 2011

ABSTRACTThe dissolution behaviour of Zircaloy clad used CANDU fuel in aqueous solutions has been examined under mildly reducing conditions at 95°C for a period of 16 months. The effects of various container components and groundwaters on the dissolution of the fuel have been investigated. The components studied were titanium (container material), carbon steel (fuel bundle support basket) and soda-lime glass beads (container infill material). Leaching solutions included deionized water (DIW) and synthetic saline groundwaters.The presence of glass beads or carbon steel did not appear to significantly affect solution concentrations of137Cs,90Sr,99Tc, or238U. Radionuclide concentrations were one to two orders of magnitude higher in saline groundwaters than in DIW. After about 30 days leaching, continued radionuclide release from the fuel was strongly inhibited in the absence of oxygen, and radionuclide concentrations in solution remained virtually constant. X-Ray photoelectron spectroscopy (XPS) measurements of the oxidation state of fuel fragments leached in groundwaters, showed a surface composition of less than UO2.33, below the postulated threshold for oxidative dissolution.
Environmental Effects on Localized Corrosion of a High-Level Nuclear Waste Container Material
Authors: Sridhar N. , Cragnolino G. , Machowski W. 
Published: March 2011

ABSTRACTThe effect of environmental variables on the localized corrosion behavior of alloy 825 is examined in this paper. Cyclic, potentiodynamic polarization tests based on a two-level, full factorial experimental design were conducted. An index incorporating both the visual and scanning electron microscope examinations of localized corrosion and the electrochemical parameters was used for the statistical analysis. The analysis showed that chloride is the single most important promoter of localized corrosion, while nitrate was the single most important inhibitor. Fluoride was a weak inhibitor, especially at low chloride levels. Sulfate was a weak promoter, especially at high chloride levels. Temperature did not have a significant effect within the chloride levels examined. Separate experiments indicated that silicon, added as metasilicate, did not have any significant effect on localized corrosion. The adverse effect of chloride was observed at concentrations as low as 100 ppm. Addition of H2O2 increased the corrosion potential of alloy 825 to a value above the repassivation potential observed in the 300 ppm chloride solution.
Enhancement of Borosilicate Glass Dissolution by Silica Sorption and Diffusion in Compacted Bentonite: A Model Study.
Authors: Curti Enzo , Smith P. A. 
Published: March 2011

ABSTRACTExperimental evidence indicates that glass corrosion rates decrease proportionally with the increase of silicic acid concentration in the solution contacting the glass surface. A minimum corrosion rate (Rsat) is reached when the solution becomes saturated with respect to an unidentified amorphous siliceous compound. In a repository where the vitrified waste form is surrounded by compacted bentonite, the silica dissolved from the glass will diffuse into the pore solution and concentration gradients will be established throughout the backfill material. The silicic acid concentration at the glass-bentonite interface, and thus the glass corrosion rate, will then be diffusion controlled. Moreover, experimental work suggests that significant sorption of silica by clay minerals in bentonite may accelerate glass corrosion.A model describing glass corrosion coupled with diffusive transport and sorption of silica in bentonite has been developed and incorporated in a FORTRAN computer code (GLADIS). The model assumes: (a) a linear isotherm for the sorption of silica (KD), (b) time and space invariant pH, temperature and ionic strength, (c) proportionality between the quantity of silica precipitated and the amount of glass dissolved and (d) cylindrical geometry. Preliminary calculations with a particular parameter set at 90°C, assuming no silica sorption on the bentonite, indicate for an unfractured glass block that a stationary state is rapidly reached in which the silica concentration at the glass-bentonite interface is lower than the saturation concentration. This implies that the glass corrodes at a more rapid rate than Rsat (RsS ∼ 8 Rsat) If moderate silica sorption is assumed (KD = 0.5 m3 kg−1), the attainment of stationary conditions is delayed by the removal of silicic acid from solution, and the average corrosion rate is further increased by a factor ∼ 2.
Phase Relations and Solubility Modelling in the Cao- SiO2- Al2O3- MgO- SO3-H2O System: For Application To Blended Cementss.
Authors: Atkins M. , Glasser F. P. , Kindness A. 
Published: March 2011

ABSTRACTCement blends are likely to form a large fraction of the materials in the near field of radioactive repositories. Being chemically reactive and slightly soluble, their effect on near field chemistry will be very marked. Predictions of nuclide migration in this zone will therefore depend in part on accurate modelling of cement chemistry.The models being developed require the establishment of correct phase relations in the Cao- SiO2- Al2O3- MgO- SO3-H2O system (the major cement components). More than 40 compatibility experiments were carried out to determine these relationships. Purified cement hydrates were shaken continuously in CO2- free water, for 10 weeks. The results from these experiments together with data from the literature, enabled us to construct a better validated phase relations scheme than has hitherto been possible.Interpretational problems were encountered. Thus, mixtures containing Ca(OH)2, gave rise to the precipitation of metastable phases. This is due to special dissolution/ precipitation equilibria obtaining at early age, allowing ‘AFm type’ (4CaO.Al2O3.SO3.12H2O) phases to form, where C3AH6 (3CaO.Al2O3.6H2O) and AFt (6CaO.Al2O3.3SO3.32H2O) are thermodynamically favoured.
Evaluation of Dry-Solids-Blend Material Source Variation on the Compressive Strength of a Cement-Based Waste form
Authors: Gilliam T. Michael , Spence Roger D. , Francis Charles L , Osborne Steve C. 
Published: March 2011

ABSTRACTA preliminary evaluation of the impact on waste-form performance characteristics due to variations in dry-solids-blend material source has been performed. The statistical treatment technique utilized for data evaluation, described herein, provides a technically sound method of comparing the effects of material source and can be used to assess the statistical significance of effects of other variables on waste-form characteristics.
Evaluation of Thermal Conductivity of Backfill Material
Authors: Xu D.M. , Mohamed A.M.O. , Yong R.N. , Cheung S.C.H. 
Published: March 2011

ABSTRACTA series of tests have been performed at the Geotechnical Research Centre on backfill material under imposed temperature gradients. It has been demonstrated that the water content distribution during the transient process does not affect the temperature distribution. The Trial Function Technique (TFT) has been applied to calculate the thermal conductivity of the backfill material. Using these values and the proposed method of solution, the temperature profiles have been calculated. The comparison between the theoretically predicted and the experimentally measured temperature profiles shows good agreement except in the vicinity of the heating boundary, where a thin thermal boundary layer exists. The vaporization process in this thin layer contributes to the turbulent effect that can be modeled by using a thermal shock condition.
Basic Research for Assessment of Geologic Nuclear Waste Repositories: What Solubility and Speciation Studies of Transuranium Elements Can Tell US
Authors: Nitsche Heino 
Published: March 2011

ABSTRACTSolubility and speciation data are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are part of predictive transport models. Results from solubility and speciation experiments of 237NpO2+, 239Pu4+, and 241Am3+/Nd3+ in J-13 groundwater (from the Yucca Mountain region, Nevada, which is being investigated as a candidate high-level nuclear waste disposal site) at three different temperatures (25°, 60°, and 90°C) and pH values (6, 7, and 8.5) are presented and compared with published modeling calculations. The comparison results indicate that there is a great need for experimental data on the solubility and speciation of transuranium elements under a wide range of conditions, for example, pH, Eh, temperature, and composition of groundwaters. Additionally, the influence of alpha radiation and the radiolysis of the secondary transuranium solids on solubility and speciation should be studied. Solubility studies and model calculations should be extended to other important long-lived nuclear waste radionuclides such as nickel, zirconium, cadmium, radium, and thorium.
Actinide Speciation by Photothermal Spectroscopies: Instrumentation Development
Authors: Berg J.M. , Tait C.D. , Morris D.E. , Woodruff W.H. 
Published: March 2011

ABSTRACTPhotoacoustic spectroscopy using pulsed laser excitation is being developed by a number of research groups as one of the most promising methods for studying speciation of actinides in solution at environmentally relevant concentrations. We present details of a number of hardware and software techniques we have implemented which, once fully developed, we believe will improve the sensitivity of the method. Our approach is based on more extensive waveform analysis. While most signal processing techniques extract the analytical signal from only a small portion of the acoustic waveform produced in the detector by an absorption event, we describe two methods that use more of the waveform. Other methods of minimizing noise sources using both hardware and software are also described.
Studies of the Effects of Degradation Products on the Sorption of Tin and Radium
Authors: Berry J.A. , Baston G.M.N. , Bond K.A. , Linklater C.M. , Pilkington N.J. 
Published: March 2011

ABSTRACTThe effects on sorption on geological media caused by the presence of materials derived from a cementitious repository have been studied. This work includes an investigation of the influence of cellulosic degradation products on the sorption of tin and radium on London clay and Caithness flagstones and the sorption of radium as a function of calcium concentration.Experimental conditions were chosen to simulate those expected close to a cementitious repository (pH=l1) and at the edge of the zone of migration of the calcium plume (pH=8). Work was carried out, (i) under baseline conditions in the absence of organic materials; (ii) with gluconate, acting as a well-characterized organic degradation product simulant; (iii) with authentic cellulosic degradation products.This investigation has shown that the sorption of tin can be affected by the presence of cellulosic degradation products whereas the sorption of radium is little affected. The sorptive behaviour of radium is however strongly influenced by the calcium concentration.