bluuebunny/crossref_metadata_2025 huggingface dataset:
Using footwall structures to constrain the evolution of low-angle normal faults
Authors: Smith S.A.F. , Holdsworth R.E. , Collettini C. , Imber J.
Published: October 2007

Controversy exists over the presence of normal faults that initiate and slip at low angles (<30°). Evidence from the Zuccale Fault, which dips
c
. 15° east on the island of Elba, Italy, indicates that the early stages of low-angle faulting were synchronous with development of subsidiary high-angle footwall faults. These footwall structures controlled fault rock distribution and caused the development of flow folds similar to those produced in analogue studies of synchronous high- and low-angle faulting. The current configuration of footwall structures indicates that the Zuccale Fault cannot have originally dipped greater than
c
. 20° east, and represents a primary low-angle normal fault.
The carbonate tectonic units of northern Calabria (Italy): a record of Apulian palaeomargin evolution and Miocene convergence, continental crust subduction, and exhumation of HP–LT rocks
Authors: IANNACE A. , VITALE S. , D'ERRICO M. , MAZZOLI S. , DI STASO A. , MACAIONE E. , MESSINA A. , REDDY S.M. , SOMMA R. , ZAMPARELLI V. , ZATTIN M. , BONARDI G.
Published: October 2007

In northern Calabria (Italy), the metasedimentary succession of the Lungro–Verbicaro tectonic unit preserves mineral assemblages suggesting underthrusting to depths in excess of 40 km. Internal deformation of these rocks occurred continuously during the following decompression. Index mineral composition associated with progressively younger tectonic fabrics indicates that a substantial part of the structural evolution took place within the blueschist-facies
P
–
T
field. Despite their tectonic and metamorphic history, the rocks of the Lungro–Verbicaro Unit preserve significant sedimentary and palaeontological features allowing correlations with successions included in adjacent thrust sheets and the reconstruction of the Mesozoic continental margin architecture. The subduction–exhumation cycle recorded by the Lungro–Verbicaro Unit is entirely of Miocene age. This portion of the Apulia continental palaeomargin was involved in convergence-related deformation not earlier than the Aquitanian. The integration of our results with available constraints on the tectonic evolution of the Apennine–Calabrian Arc system suggests that subduction and most of the subsequent exhumation of the Lungro–Verbicaro Unit occurred, up to Langhian time, at maximum vertical rates in excess of 15 mm a
−1
. The exhumation process was then completed, at much slower rates (<2 mm a
−1
) in Late Miocene time, as indicated by both apatite fission-track data and stratigraphic information.
Mining User preference using Spy voting for search engine personalization
Authors: Ng Wilfred , Deng Lin , Lee Dik Lun
Published: October 2007

This article addresses search engine personalization. We present a new approach to mining a user's preferences on the search results from clickthrough data and using the discovered preferences to adapt the search engine's ranking function for improving search quality. We develop a new preference mining technique called
SpyNB
, which is based on the practical assumption that the search results clicked on by the user reflect the user's preferences but does not draw any conclusions about the results that the user did not click on. As such, SpyNB is still valid even if the user does not follow any order in reading the search results or does not click on all relevant results. Our extensive offline experiments demonstrate that SpyNB discovers many more accurate preferences than existing algorithms do. The interactive online experiments further confirm that SpyNB and our personalization approach are effective in practice. We also show that the efficiency of SpyNB is comparable to existing simple preference mining algorithms.
Supporting intelligent Web search
Authors: Coyle Maurice , Smyth Barry
Published: October 2007

Search engines continue to struggle to provide everyday users with a service capable of delivering focussed results that are relevant to their information needs. Moreover, traditional search engines really only provide users with a starting point for their information search. That is, upon selecting a page from a search result list, the interaction between user and search engine is effectively over and the user must continue their search alone. In this article, we argue that a comprehensive search service needs to provide the user with more help, both at the result list level and beyond, and we outline some recommendations for intelligent Web search support. We introduce the SearchGuide Web search support system and we describe how it fulfils the requirements for a search support system, providing evaluation results where applicable.
YASS
Authors: Majumder Prasenjit , Mitra Mandar , Parui Swapan K. , Kole Gobinda , Mitra Pabitra , Datta Kalyankumar
Published: October 2007

Stemmers attempt to reduce a word to its stem or root form and are used widely in information retrieval tasks to increase the recall rate. Most popular stemmers encode a large number of language-specific rules built over a length of time. Such stemmers with comprehensive rules are available only for a few languages. In the absence of extensive linguistic resources for certain languages, statistical language processing tools have been successfully used to improve the performance of IR systems. In this article, we describe a clustering-based approach to discover equivalence classes of root words and their morphological variants. A set of string distance measures are defined, and the lexicon for a given text collection is clustered using the distance measures to identify these equivalence classes. The proposed approach is compared with Porter's and Lovin's stemmers on the AP and WSJ subcollections of the Tipster dataset using 200 queries. Its performance is comparable to that of Porter's and Lovin's stemmers, both in terms of average precision and the total number of relevant documents retrieved. The proposed stemming algorithm also provides consistent improvements in retrieval performance for French and Bengali, which are currently resource-poor.
Performance analysis and workload characterization of the 3DMark05 benchmark on modern parallel computer platforms
Authors: Sibai Fadi N.
Published: October 2007

With ever increasing CPU and graphics card speeds, and improved sophistication, stunning visual effects, and growing scene detail and real life-like content of 3D games, 3DMark® emerged as the leading PC benchmark for 3D gaming performance with several millions of worldwide downloads. Its tests are at the cutting edge of consumer graphics and push the limit of 3D rendering with spectacular scenes, and state of the art lighting techniques. The benchmark scores help quickly differentiate the platforms with state of the art graphic cards and processors from those with older components. In this paper, we analyze the scaling of the 3DMark®05 benchmark with CPU frequency, number of CPUs, number of GPUs, and number of threads supported by the hardware. We also characterize the benchmark's workload. These results reveal that the benchmark scales well indicating that 3D games if implemented with multiple Physics and Artificial Intelligence or other relevant content threads should show good scaling too on multi-CPU and multi-GPU platforms. The characterization results reveal the close dependence of 3D graphics applications on the memory subsystem's performance as 1 out of 2 instructions is a load or store instruction. The results also revealed that there is a direct correlation with the Game Tests' performance and the number of cache memory read misses per instruction retired, the number of stores retired per instruction retired, the number of polygons per Draw*Primitive; and the number of setvertexshader calls per frame. All these events relate to the memory subsystem performance generally linking the 3D graphics applications' performance and the 3DMark® overall score to the platform's memory performance. Salient microarchitectural performance events of the CPU tests were also memory-related.
Introduction to the special issue on the 2006 reconfigurable and adaptive architecture workshop
Authors: Aggarwal Aneesh , Bose Pradip , Zahran Mohamed
Published: October 2007

The papers that follow comprise the proceedings of the first Reconfigurable and Adaptive Architecture Workshop (RAAW 2006) that was held in conjunction with the 39
th
International Conference on Microarchitecture in Orlando, Florida.
Custom code generation for soft processors
Authors: Labrecque Martin , Yiannacouras Peter , Steffan J. Gregory
Published: October 2007

Embedded systems designers that use FPGAs are increasingly includingsoft processorsin their designs (configurable processors built in the programmable logic of the FPGA). While there has been a significant amount of research on adding custom instructions and accelerators to soft processors, these are typically used to extend an unmodified base ISA targeted by generic compilation such as with unmodified gcc. In this paper we explore several opportunities for the compiler to optimize the code generated for soft processors through application-specific customization of the base ISA---techniques that are orthogonal to adding custom instructions. In particular we explore: (i) low level software-hardware trade-offs between basic instructions; (ii) the utility of ISA-specific features---in particular for the delay slots and Hi/Lo registers in the MIPS ISA; and (iii) application specific register management. We find that through these techniques that have no hardware cost we can improve the area efficiency of soft processors by 12% on average across a suite of benchmarks, and by up to 47% in the best case.
Molten Salts and Ionic Liquids - Are They Not the Same Thing?
Authors: Wilkes John S.
Published: October 2007

This is the text of the speech by the author following the presentation of the Physical and Analytical Division Max Bredig Award in Molten Salt Chemistry at the 210th meeting of the Electrochemical Society in Cancun, Mexico.
The Preparation and Characterization of Bombyx Mori Silk Nanocomposites Using Ionic Liquids
Authors: Fox Douglas , Fylstra Paul , Hanley Matthew , Henderson Wesley A. , Trulove P. C. , Bellayer Severine , Gilman Jeffrey , De Long Hugh C.
Published: October 2007

Silk is one of the most desirable textile fibers due to its unprecedented flexibility, strength, and chemical resistance. Recent work has shown that ionic liquids possess great potential for dissolving and processing silk. Furthermore, ionic liquids have been shown to improve dispersion of nanoparticles throughout conventional polymer networks. In our current work, we have used imidazolium based ionic liquids to dissolve silk and disperse clay, carbon nanotubes, and chitin using film casting, wet spinning, and electrospinning techniques. The structural characteristics and morphology were determined using x-ray diffraction, Raman spectroscopy, laser scanning confocal microscopy, and scanning electron microscopy. Thermogravimetric analysis and differential scanning calorimetry were used to assess the potential benefits of adding nanocomposites to silk fibers and films. It was determined that carbon nanotubes offer the best potential for improving the thermal properties of silk.
Amino Acid Based Ionic Liquids: Solvents for Improved Biopolymer Dissolution
Authors: Hanley Matthew , Green J. M. , Henderson Wesley A. , Fox Douglas , De Long Hugh C. , Trulove P. C.
Published: October 2007

The dissolution of bombyx mori silk was investigated in a room- temperature ionic liquid with an amino acid anion. Silk was found to be soluble in an ionic liquid with a glycine based anion to over 26 w%. The reconstitution of the dissolved silk from this ionic liquid solution was critically depended on solvent and processing conditions. Processing with methanol formed a highly crystalline material and the crystallinity was found to increase with the time of contact with the solvent. Silk materials containing either multiwalled carbon nanotubes or montomorillonite clays were prepared by first adding the nanomaterials to the silk-ionic liquid solution, and then reconstituting the silk using a solvent based process. The structure and morphology of the processed silk and silk composites were characterized using scanning electron microscopy (SEM), Raman spectroscopy, and x-ray diffraction (XRD).
Flue Gas Cleaning With Alternative Processes and Reaction Media
Authors: Rasmussen Soren Birk , Huang Jun , Riisager Anders , Hamma Hind , Rogez Jacquez , Winnick J. , Wassserscheid Peter , Fehrmann Rasmus
Published: October 2007

Alternative methods to the traditional industrial NOX and SOX flue gas cleaning processes working at lower temperatures and/or leading to useful products are desired. In this work we present our latest results regarding the use of molten ionic media in electrocatalytic membrane separation, ionic liquid reversible absorption and supported ionic liquid deNOX catalysis. Further development of the methods will hopefully make them suitable for installation in different positions in the flue gas duct as compared to the industrial methods available today.
Decomposition of 2,4',5-Trichlorobiphenyl by Using Molten Salt
Authors: Yokka Yasufumi , Kimura Masayoshi , Sato Yuzuru
Published: October 2007

The decomposition of 2,4',5-trichlorobiphenyl as a derivative of PCB was studied by means of the injecting the solution into NaOH-Na2CO3 or KOH-K2CO3 molten salts. The solution of 2,4',5-trichlorobiphenyl dissolved in an organic solvent were fed into the molten salts together with the carrier gas (N2-21%O2) through the injection tube. The experiments were carried out in the temperature range of 500-700{degree sign}C by immersing the injection tube into the molten salts. Potassium system showed relatively higher decomposition efficiency than sodium system at low temperature. The decomposition efficiency of 2,4',5-trichlorobiphenyl depended on the temperature and was approximately 99.999% over 600{degree sign}C in both systems.
About the Acidity Level in Room Temperature Ionic Liquids
Authors: Robert Thierry , Olivier-Bourbigou Helene , Magna Lionel , Gilbert Bernard
Published: October 2007

The Bro̸nsted acidity level was evaluated for ionic liquids to which a strong acid has been added. The evaluation method is based on the determination of the Hammett acidity functions H0, using UV-Visible spectroscopy. The acidity of protons is mainly determined by their solvation state and consequently, the properties of protons depend on both the nature of the solvent and the nature and concentration of the acid. In practice, it was found that, for the investigated ionic liquids, the cation as well as the added acid nature does not play a dominant role, whereas changing the anion nature may lead to very different acidities. Indeed, for a similar content of added acid, the measured acidity levels are in the order: PF6- > BF4- > NTf2- > OTf-. The problems of the influence of impurities on the final acidity and of the weakly dissociating character of the ionic liquid are addressed.
Molecular Modeling of Interactions between Ionic Liquids and Metal Surfaces
Authors: Carper William R. , Nooruddin Naveed
Published: October 2007

The interactions between metal surfaces and selected ionic liquids is examined in this report. The ionic liquids include a series of seven cationic imidazolium derivatives with PF6 as the anion. The tribological properties of these ionic liquids and their interactions with aluminum and steel are modeled using a smooth aluminum oxygen surface. The ionic liquids are placed above the aluminum oxygen surface and allowed to form a complex with this surface. Enthalpies of complex formation correlate with the tribological properties of the seven ionic liquids.
Characterization of Flammability Properties of Ionic Liquids
Authors: Gilman Jeffrey , Fox Douglas , Morgan Alexander , Shields John R. , Maupin Paul H. , Lyon Richard E. , De Long Hugh C. , Trulove P. C.
Published: October 2007

Flammability properties of imidazolium-based ionic liquids have been measured using cone calorimetry and microscale combustion calorimetry. The flammability properties of ionic liquids are comparable to aliphatic hydrocarbon plastics (polyethylene and polyamide), and lower than high boiling organic solvents (ethyl lactate and dimethylsulfoxide). Several structure-property relationships are observed.
Ionic Liquid Impregnated Resins in Solid-Liquid Separations
Authors: Cocalia Violina A. , Rogers Robin D.
Published: October 2007

The extraction of TcO4-, UO22+, and iodine species onto a solid resin (XAD-7) impregnated with trihexyltetradecylphopsphonium chloride (Cyphos IL 101) has been investigated. Radiotracer experiments indicate that pertechnetate and iodine species can be separated from hexavalent actinides from aqueous media at moderately low acidities, and that pertechnetate and iodine can be stripped at very low or very high nitric acid concentrations. Chloride leaching experiments suggest that the solid impregnated resin behaves as an ion exchange resin.
The Ho3+ Hypersensitive Transitions as Structural Probes for Molten Rare-Earth Ahlorides
Authors: Papatheodorou George N. , Kalampounias Angelos G.
Published: October 2007

The electronic absorption spectra of the f ← f transitions of Ho3+ in solid and molten Cs2NaHoCl6 elpasolite and in Y(Ho)Cl3 have been measured from room temperature up to above the melting point of both compounds. Emphasis is given on the ligand field spectra of the 5G6 ← 5I8 hypersensitive transition. Smooth spectra changes are observed upon melting the solids. In conjuction with Raman spectroscopic measurements the absorption spectra are attributed to HoCl 3− 6 octahedra in distorted geometries. The spectra of molten Y(Ho)Cl3 are correlated to the elpasolite spectra as well as with the spectra of La(Ho)Cl3 and Gd(Ho)Cl3 to deduce the possible structure of the host rare-earth chlorides.
A Polarizable-Ion Potential for Trihalides: from Clusters to Liquid Structure
Authors: Akdeniz Zehra , Ruberto Romina , Pastore Giorgio , Tosi Mario
Published: October 2007

We examine by classical molecular-dynamics simulations how an ionic-interaction law determined on isolated molecular clusters of trivalent-metal halides fares in accounting for the pair structure of the liquid phase of these compounds near freezing. The model supplements pair potentials with valence- shell polarization terms for the halogens. The main focus is on AlCl_3, for which a variety of data indicate melting from an ionic layer structure into a dimer-based liquid. Good agreement is found with neutron diffraction data on Al-Cl and Cl-Cl bond lengths in the melt, but the sharpness of the main peaks in the neutron radial distribution function is overemphasized. The model reproduces the main features of the neutron structure factor, showing three peaks due to intermediate-range order and to charge and density short-range order. We also compare the running partial coordination numbers in a series of molecular melts, i.e. AlCl_3, AlBr_3, GaBr_3, GaI_3, and FeCl_3.
Empirical Evaluation of the Cryolite Melts Properties
Authors: Redkin Alexander A. , Zaikov Yurii , Tkatcheva Olga , Filatov Eugene
Published: October 2007

Experimental investigation of their properties such as density, electrical and thermal conductivity, etc., takes much time. In order to reduce this time it is possible to combine direct measurements with empirical evaluation using data available for molten salts. Empirical equations for electrical and thermal conductivity have been obtained for basic molten electrolytes of industrial electrolysis.
Quantum Chemical Studies of Li Ion Hopping Mechanism in Polymer Electrolytes
Authors: Redfern Paul , Kupka Teobald , Curtiss Larry A.
Published: October 2007

The potential energy surface for lithium cation hopping between the oxygens of two polyethylene oxide chains was studied at the molecular level using ab initio molecular orbital theory. Various levels of theory were used. A simple model of two dimethyl ether molecules was used to mimic two polyethylene oxide chains. The barrier for Li cation hopping between the two chains was found to increase with distance between the two oxygens.
Ionic Melt Electroltyes for Lithium Battery Applictions
Authors: Creager Stephen , Hallac Boutros B. , Geiculescu Olt , Rama Rajagopal , Herath Mahesha , DesMarteau Darryl D.
Published: October 2007

Ionic melt electrolytes consisting of lithium salts of fluorosulfonamide anions covalently attached to oligomeric polyether chains were synthesized and characterized with respect to structure and ion transport characteristics. Conductivity data are reported for melts of variable ether- oxygen-to-lithium ratio, and for melts having different amounts of polyether plasticizers added. Conductivities are generally high relative to true polymer electrolytes.
Ionic Liquid Fluorohydrogenates and Their Applications
Authors: Hagiwara R. , Nohira Toshiyuki , Shimada Takashi , Fujinaga Takashi , Konno Soichiro , Tsuda Tetsuya
Published: October 2007

The recent results are described on the developments of ionic liquid (IL) fluorohydrogenates with high ionic conductivities and wide electrochemical windows. Several cyclic ammonium cations have been found to be combined with fluorohydrogenate anions giving a vacuum stable ionic liquid fluorohydrogenates, Cat+[(FH)2.3F]−. N-ethyl-N-methylpyrrolidinium fluorohydrogenate, EMPyrro(FH)2.3F, and N-allylpyrridinium fluorohydrogenate, APyrrid(FH)2.3F, exhibit wide electrochemical windows of around 5 V. A fluorohydrogenate fuel cell (FHFC) using HF-deficient IL, 1-ethyl-3-methyl- imidazolium fluorohydrogenate, EMIm(FH)1.3F, as the electrolyte operates at 120{degree sign}C without humidification. The maximum output power so far obtained in the preliminary cell test is 41 mWcm-2 (0.41 V and 100 mA cm-2) at 40{degree sign}C without humidification.
Progress in Surface Finishing with Lewis Acidic Room-Temperature Chloroaluminate Ionic Liquids
Authors: Tsuda Tetsuya , Hussey Charles L. , Stafford G. R.
Published: October 2007

In this article, we survey the progress that has been attained to date in the area of surface finishing with solvents derived from Lewis acidic room-temperature chloroaluminate ionic liquids, such as AlCl3-1-ethyl-3-methylimidazolium chloride and AlCl3-1-(1-butyl)pyridinium chloride. This field of study has received constant attention since the late 1970's. For descriptive purposes, the surface finishing technology associated with these ionic liquids is divided into four categories: Al plating, underpotential plating of binary Al alloys, overpotential plating of binary Al alloys, and overpotential plating of ternary Al alloys. We include in this report recent experimental results describing the electrodeposition of AlHf, AlW, and AlInSb alloys from the 66.7-33.3 mole percent AlCl3-1-ethyl-3-methylimidazolium chloride ionic liquid.
Practical Aluminum Plating from a Room Temperature Ionic Liquid
Authors: Carter Michael T. , Bourgon Gregory
Published: October 2007

We report on work performed at Eltron Research on the more practical aspects of chloroaluminate RTILs as aluminum plating baths for production of corrosion resistant coatings on various base metals, including stainless steel. We examined voltage- current characteristics and current efficiency for Al electroplating from both neat melts and melts with organic cosolvents. The effects of organic cosolvent on electrochemical behavior, morphology, thickness and appearance of Al plate were characterized. The throwing power of the RTIL plating bath shows promise for practical application in plating onto fasteners and other small parts.
Electrodeposition of Tin from 1-Methyl-3-ethylimidazolium Chloride/AlCl3/SnCl2 Room Temperature Molten Salts
Authors: Zhu Derong , Sun Hui , Fung Yingsing
Published: October 2007

The electrodeposition of tin was investigated in the room temperature molten salt based on 1-methyl-3-ethylimidizalium/ AlCl3/SnCl2. The results show that the morphology and size of the tin crystallites are strongly influenced by the composition of the melts and the deposition potentials, producing tin deposits with different shapes and widely various size ranges from several micrometers to nanometers. Double potentiostatic pulse deposition technique has been used to control the morphology and particle size of tin deposits. Nano-size tin particles around 50nm with more regular shape and uniform size distribution can be obtained successfully by a balanced control of the nucleation and growth of the tin deposits.
Electrodeposition of In-Sn Alloys in EMI-BF4-Cl Ambient Temperature Melts with Current Pulses
Authors: Noda Masashi , Morimitsu Masatsugu , Matsunaga Morio
Published: October 2007

The electrodeposition of indium-tin alloys was investigated in EMI-BF4-Cl ambient temperature melts with current pulses. The alloy deposits with higher indium by the pulsed method. In the melt containing high concentration of the stannous ion, the indium content decreased with the off-time length. This variation of the indium content with the off-time caused by the exchange reaction between indium metal in deposits and stannous ion in melt during off-time. The electrode potentials at the end of off-time exist in the range where the exchange reaction occurs.
Nickel Electrodeposition from a Room Temperature Eutectic Melt
Authors: Bund Andreas , Zschippang Eveline
Published: October 2007

This paper discusses recent results from the authors' lab dealing with nickel electrodeposition from a choline chloride/urea eutectic melt (molar ratio 1:2). The temperature dependence of the viscosity of the melt was investigated with the quartz crystal microbalance (QCM). It has been found that with increasing nickel content the viscosity of the electrolyte increases and that the melt shows viscoelastic behavior up to ca. 60{degree sign}C. Using the QCM in the electrochemical mode (EQCM) the current efficiency of the nickel deposition at 100{degree sign}C was studied.
Electrodeposition of Cobalt from an Imide-Type Room-Temperature Ionic Liquid
Authors: Katayama Yasushi , Fukui Ryuta , Miura Takashi
Published: October 2007

The electrodeposition of cobalt was investigated in an ionic liquid, 1-n-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI). The overpotential for the electrodeposition of Co was reduced remarkably by elevating temperature up to 200 {degree sign}C, probably due to the change in the coordination environment of Co species. On the other hand, the addition of acetone led to the decrease in the overpotential, indicating the selective coordination of Co cation with acetone enhance the charge transfer rate. It has been suggested that the charge transfer and crystal growth in the ionic liquid are affected by the coordination environment of the dissolved metal species and the structure of electric double layer.
Electrochemical Alloying of Copper Substrate with Tin Using Ionic Liquid as an Electrolyte at Medium-Low Temperatures
Authors: Murase Kuniaki , Kurosaki Ryoichi , Katase Takuma , Sugimura Hiroyuki , Hirato Tetsuji , Awakura Yasuhiro
Published: October 2007

Electrochemical alloying of Cu substrate through a reduction-diffusion method was investigated using ionic liquid, trimethyl-n-hexylammonium bis[(trifluoromethyl)sulfonyl]amide, as a solvent for an electrolytic bath. The use of the ionic liquid rendered it possible to raise the processing temperature beyond 100 åC so as to form the Cu-Sn layers faster than in the case of an aqueous media. The layers obtained from Cu thin layer under potentiostatic condition were silver-gray speculum metal composed of Cu6Sn5, Cu3Sn, and Cu10Sn3 intermetallic phases, while those prepared under galvanic contact condition involved a β-Sn phase containing a trace amount of copper. The formation of each Cu-Sn phase was discussed in terms of thermodynamics of alloy formation.
Electrodeposition of Refractory Metals from Some ZnCl2 Based Molten Salts at 150-250{degree sign}C
Authors: Nohira Toshiyuki , Nakajima Hironori , Kitagawa Kan , Hagiwara R. , Nitta Kouji , Inazawa Shinji , Okada Kazunori
Published: October 2007

The solubility of WO3 in a eutectic NaCl-KCl-ZnCl2 (20:20:60 mol%) melt at 250 {degree sign}C was increased by addition of KF, which enabled the electrodeposition of metallic tungsten. A smooth and dense tungsten film having 0.7 μm thickness was obtained on a nickel substrate by potentiostatic electrolysis at 0.06 V vs. Zn(II)/Zn for 3 h in the NaCl-KCl-ZnCl2-KF(4 mol% added)-WO3(0.54 mol% added) melt at 250 {degree sign}C. The surface of the nickel contact probe pin for semiconductor testing, which had been manufactured by the conventional LIGA process, was successfully coated with tungsten by using this molten salt. To lower the electrodeposition temperature, a new molten salt system, EMPyrCl-ZnCl2, was developed. An equimolar EMPyrCl-ZnCl2 system was a stable liquid at 40-200 {degree sign}C. A metallic molybdenum film was electrodeposited on a nickel substrate in the melt containing KF and MoCl5 at 150 {degree sign}C.
Electrodeposition of Iron from Molten Mixed Chloride/Fluoride Electrolytes
Authors: Haarberg Geir Martin , Kvalheim Eirin , Rolseth Sverre , Murakami Tsuyoshi , Pietrzyk Stanislaw , Wang Shulan
Published: October 2007

The electrochemical behaviour of dissolved Fe2O3 and the electrodeposition of iron in molten CaCl2-CaF2 (80-20 mol %) and other mixed chloride/fluoride electrolytes was studied at 827 {degree sign}C and 890 {degree sign}C by cyclic voltammetry, chronoamperometry and galvanostatic electrolysis, and deposits were characterized by XRD and SEM. Pure iron was obtained in these melts at current efficiencies greater than 90 %. High cathodic current densities (~0.5 A cm2) were achieved by using a rotating cathode. The work is related to studies of the possible development of new processes for the production of iron and steel with large reductions of CO2 emissions.
Direct Reduction of Vanadium Oxide in Molten CaCl2
Authors: Suzuki Ryosuke O. , Ishikawa Hiroyuki
Published: October 2007

A process consisted of electrolysis of CaO in the molten CaCl2 and of calciothermic reduction was applied to prepare metallic vanadium directly from V2O3. The fine metallic powder containing 1860 mass ppm oxygen was successfully obtained using 0.5mol%CaO-CaCl2 melt for 10.8 ks at 1173 K. The oxygen level from the oxide fitted with the demand for hydrogen storage application, but it remained nearly constant even when the twice electricity was supplied. The commercial grade powder contained 1.48% oxygen was, however, well deoxidized to 10 ppm. The large amount of by-product, CaO, due to reduction and the large surface area of the fine particles are the possible reasons of high oxygen content in the reduced powder.
Phase Composition of the Cathodic Products Obtained in Alkali Chloride Melts Containing Potassium Monooxyfluoride Complexes of Tantalum
Authors: Grinevitch V. V. , Kuznetsov Sergey A. , Arakcheeva A. V. , Gaune-Escard Marcelle
Published: October 2007

The electrochemical behavior of molten salts systems where LiCl, NaCl, NaCl-KCl, KCl and CsCl were used as solvent for K2TaF7 and K3TaOF6 was investigated. In particular, the influence of the electrolysis parameters, such as concentration of tantalum species in electrolyte, temperature and current density on the cathodic products phase composition was determined by X-ray diffraction and scanning electron microscopy. Several phases generally crystallized at the cathode simultaneously. Among identified phases were metallic tantalum in cubic (α) and tetragonal (β) crystal modifications, tantalum oxide bronzes (hexagonal, tetragonal, cubic) and TaO. The most characteristic phases for the CsCl melt were two isostructural compounds with pyrochlor type crystal lattice CsTa52+zO5+yF1- y and CsTa5-x2+zO5+yF1-y. The former deposited in the form of transparent dielectric crystals and the later - in the form of metal-like conductive ones. This latter compound seems to be synthesized for the first time.
Anodic Behaviors of Noble Metals in Eutectic LiCl-KCl Melt
Authors: Takenaka Toshihide , Kawakami Masahiro
Published: October 2007

The anodic behaviors of some noble metals and their alloys in dehydrated LiCl-KCl eutectic melt have been studied as a basic study on a new reprocessing process of spent UO2 nuclear fuel by an electrorefining technique. Palladium and Ru dissolved anodically as Pd2+ and Ru3+, respectively. Rhodium dissolved as Rh3+, and was passivated by surface film formation. The potentials where the steady dissolution current density was 10-3 A/cm2 were 3.02V for Pd, 3.08V for Rh and 3.12V for Ru, These values were more positive than the reported value of UO2. The anodic behaviors of Pt-Rh and Pd-Ru alloys were explained from those of each component, and no peculiar influence by alloying was seen. These results indicate that the noble metals and alloys can be separated from UO2 by leaving them in the anode by the control of the anode potential.
Effect of Production Methods on the Features of Sodium-Reduced Tantalum Powders
Authors: Kolosov Valery N. , Miroshnichenko Marina , Orlov Veniamin , Prokhorova Tatiana
Published: October 2007

The paper presents a study into production method effect on characteristics of sodium-reduced tantalum powders. The powders were produced by feeding liquid sodium onto the surface of a melt consisting of K2TaF7 and a flux (I) and by feeding solid K2TaF7 onto the surface of a melt consisting of liquid sodium and a diluent salt (II). It is shown that production method renders essential influence to powder morphology and specific surface.
Composition and Properties of Oxide Films on a Ferriti Steel and a Nickel-Based Alloy in Molten Hydroxide - Carbonate Electrolytes
Authors: Tzvetkoff Tzvety B. , Bojinov Martin S.
Published: October 2007

The composition of the anodic films formed on Ni-10%Cr and Fe- 18%Cr in molten NaOH with and without the addition of carbonate have been characterised ex-situ by X-ray electron spectroscopy (XPS) and Auger electron spectroscopy (AES). Voltammetric and electrochemical impedance spectroscopic measurements were employed to characterise the conduction mechanism in the oxide layers formed.. The oxide formed on Ni-10%Cr and Fe-18%Cr in molten hydroxide is essentially a duplex layer, the inner part of which grows via solid-state diffusion-migration of point defects. This inner part behaves as a p-type semiconductor on Ni-10%Cr and a n-type semiconductor on Fe-18%Cr. The outer part of the layer grows via dissolution-precipitation mechanism to a certain extent analogous to that operative for films formed in high-temperature aqueous environments. The ability of the Mixed- Conduction Model to account for the electrochemical data points to a general similarity of the oxide film formation process in high-temperature electrolytic media.
Revival of Halide Salts as High-Temperature Heat-Transfer Media: Key Technical and Scientific Issues
Authors: Williams David F.
Published: October 2007

The U.S. Department of Energy - Office of Nuclear Energy is exploring the use of molten salt as a primary coolant in a high-temperature reactor and as a secondary coolant to shuttle heat from a high-temperature reactor to a hydrogen production plant. Industries have used nitrate salts as heat transfer agents in the intermediate temperature range (to ~600{degree sign}C). Halides are used in industrial processes at much higher temperatures, for example in the production of a number of refractory and active metals. Chlorides and fluorides are uniquely well suited to higher temperature applications because of their thermodynamic stability, excellent heat transfer properties and low-vapor pressure. This paper summarizes an evaluation of salts for high-temperature heat transfer applications based upon physical and chemical properties, heat transfer performance, material compatibility, and economics. The understanding of corrosion phenomena in molten halides is amongst the most important of the key scientific issues
Thermodynamics and Transport Properties of the CeBr3 - MBr Binary Systems
Authors: Gaune-Escard Marcelle , Rycerz Leszek , Ingier-Stocka Ewa , Gadzuric Slobodan
Published: October 2007

Detailed investigations of phase equilibrium in the CeBr3-MBr (M=Li, Na, K, Rb) systems was conducted by Differential Scanning Calorimetry (DSC). CeBr3-LiBr and CeBr3-NaBr are simple eutectic systems. CeBr3-KBr is characterized by two congruently melting compounds, namely K3CeBr6 and K2CeBr5, and three eutectics. K3CeBr6 forms at 775 K and melts congruently at 879 K. K2CeBr5 melts congruently at 874 K. CeBr3-RbBr exhibits two eutectics, one congruently melting Rb3CeBr6 compound (formation at 614 K, solid-solid phase transition at 695 K and melting at 966 K) and two compounds that decomposes peritectically at 830 K and 811 K (Rb2CeBr5 and RbCe2Br7, respectively). The electrical conductivity of all liquid CeBr3- MBr mixtures and pure components was measured over an extended range including temperatures below solidification. The obtained results are discussed in the term of possible complex formation
CEMSO (Catalyst Enhanced Molten Salt Oxidation) for Complete and Continuous Pyrochemical Reprocessing of Spent Nuclear Fuel: An Overview of a Viable New Technology for Next Generation Nuclear Reactors
Authors: Griffiths Trevor R. R. , Volkovich Vladimir A. , Carper William R.
Published: October 2007

Catalyst Enhanced Molten Salt Oxidation provides a rapid and efficient separation and recycling technology for spent nuclear fuel. Air bubbled into molten carbonate creates peroxide and superoxide ions and addition of a small amount of nitrate acts as a catalyst that maintains and increases their concentration. Density Functional Theory calculations have confirmed that an adduct is formed between peroxide and nitrate, as the first step in superoxide formation. Uranium dioxide (powder and ceramic) is completely oxidized to insoluble uranates by air sparging in molten carbonates, (solubility of uranates ca. 200 ppm). After removing uranates the fission product elements in solution can be precipitated (>97% efficiency) as phosphates, in ca. 3h, and the carbonate melt re-cycled. The application of CEMSO to both reprocessing and radioactive waste is a valuable tool and technique and fully applicable to current decommissioning and future nuclear reactor technology. Areas needing further research are identified.
Spectroelectrochemical Study of Uranium and Neptunium in LiCl-KCl Eutectic Melt
Authors: Polovov Ilya B. , Sharrad Clint A. A. , May Iain , Vasin Boris D. D. , Volkovich Vladimir A. , Griffiths Trevor R. R.
Published: October 2007

Experimental set up for spectroelectrochemical measurements was designed. Uranium(III) ions, UCl6 3-, are formed during anodic dissolution of metallic uranium and prolonged contact of U(IV)- containing melts with uranium metal. UCl4 dissolution in 3LiCl- 2KCl melt leads to the formation of UCl6 2- ions. They undergo a two-step electrochemical reduction: U4+→U3+ recharge followed by U deposition. Neptunium(IV) chloride dissolves in 3LiCl-2KCl melt producing NpCl6 2- ions. Electrochemical reduction of Np(IV) on a glassy carbon electrode results in the formation of NpCl6 3- ions and then leads to the deposition of neptunium metal. Electronic absorption spectra of uranium (III, IV, V and VI) and neptunium (III and IV) species in 3LiCl-2KCl eutectic were measured at 450 oC.
Thermal Cycling of Epoxy Coatings using Room Temperature Ionic Liquids
Authors: Hinderliter Brian , Allahar Kerry , Bierwagen Gordon , Tallman Dennis E. , Croll Stuart
Published: October 2007

Nonaqueous room temperature ionic liquids (RTILs) offer a new method of using electrochemical impedance spectroscopy (EIS) to analyze coatings without the confounding effects, such as plasticization, associated with an aqueous working fluid(1). Thermal cycling has been used as an accelerated testing method for ranking the corrosion protection of coatings(2,3). The influence of thermal cycling on the degradation of a coating was investigated using a hydrophilic RTIL as the electrolyte for EIS experiments. The change in diffusion coefficient, saturated water volume fraction and activation energy for the absorption and desorption of water by the coating was obtained.
Measurement and Thermodynamic Analysis of NiF2/Ni Electrode Potential in a Dehydrated Melt of NH4F·2HF
Authors: Tasaka Akimasa , Morimoto Eiki , Mimoto Atsuhisa , Inoue Akitoshi , Inaba Minoru
Published: October 2007

A Ni reference electrode was prepared and its potential was also determined in a NH4F•2HF melt at 100{degree sign}C. The value of potential on the Ni electrode was unstable for 30 days. On the other hand, potentials on Ni electrodes treated with anodic oxidation at 10 mA/cm2 for 3 days and thermal fluorination with NF3 under 1 atm at 300{degree sign}C for 1 hour became stable after shorter time. The former was 0.075 V and the latter was 0.072 V against hydrogen evolution potential (V vs. H2). The value of potential was almost the same in every measurement. SEM observation and XPS analysis revealed that both pre-treated Ni electrodes were covered with the dense layer composed of NiF2 with a small amount of nickel oxide and/or nickel oxyfluoride. The potential of the NiF2/Ni electrode at 100{degree sign}C calculated from the thermodynamic data is - 0.178 V vs. H2. This value of potential was different from the observed one. On the other hand, the potential of the NiO/Ni electrode calculated from thermodynamic data is 0.164 V vs. H2. As the observed value of potential on the Ni electrode is between both potentials of the NiF2/Ni and the NiO/Ni electrodes, its potential may be determined by nickel oxyfluoride, NiOxFy, in the surface layer of the Ni electrode. Therefore, it is concluded that a Ni electrode covered with the oxidized layer mainly composed of NiF2 is useful as a reference electrode for electrochemical measurement and electrolytic production of NF3 using a nickel anode.
Corrosion Behavior of the Electrochemical Couple: Hastelloy/Carbon Material in Zirconium Fluoride - Sodium Fluoride Melts
Authors: Omel'chuk Anatolii A. , Volkov Sergei V. , Voronin Boris M. , Buryak Nikolai I. , Andriiko Alexander A. , Bakai Alexander S. , Savchuk Ruslan N.
Published: October 2007

Time dependencies for the parameters (current, voltage, inner resistance) of short-circuited galvanic cell: Hastelloy-carbon material have been studied in NaF-ZrF4 eutectic melt at 600- 650oC. Analysis of these data, together with the data on polarization of separate electrodes at open circuit conditions, showed that short-circuit current is related to the rate of corrosion of the alloy contacted with carbon. In the presence of zirconium, the short-circuit current corresponds to the rate of zirconium interaction with the fluoride melt and can be used for studies of its dissolution kinetics. It was found that contact of Hastelloy with carbon material results in an increase of corrosion rate both in pure NaF-ZrF4 eutectic melt and with the additives of LaF3. The presence of zirconium in fluoride melt suppresses the corrosion process.
Speciation of Molybdenum and Tungsten in Molten Chlorides: A Spectroelectrochemical Study
Authors: Volkovich Vladimir A. , Danilov Danil A. A. , Polovov Ilya B. , Vasin Boris D. D. , Griffiths Trevor R. R. , Aleksandrov Denis E. , Tropin Oleg A. A. , Tsarevskii Dmitrii V. V.
Published: October 2007

Speciation of tungsten and molybdenum in alkali chloride melts (based on NaCl-2CsCl, NaCl-KCl and 3LiCl-2KCl mixtures) was studied between 450 and 750 oC using electronic absorption spectroscopy. Only W(IV) and W(V) chloro- and oxychlorospecies can be stabilised under conditions studied. Tungsten(IV) chloride ions are very sensitive to oxide/hydroxide impurities present in the melt. Anodic dissolution of W metal at anodic current densities in the range of 0.005-0.1 A/cm2 produces only WCl6 2- ions that can be electrochemically oxidised to WCl6 -. Small amounts of oxide ions present in the melt result in a gradual conversion of W(IV) chloro-species into W(IV) oxychloro-species. In the presence of O2 WCl6 2- is oxidised into tungsten(V) species WOCl5 2-. Molybdenum forms Mo(III), (IV) and (V) species. MoCl6 2- complex ions in chloride melts can be obtained by reacting MoO2 with HCl, or by electrochemical oxidation of Mo(III) (MoCl6 3- → MoCl6 2-) on a glassy carbon electrode.
Hydrogen Electrode Reaction in Some Imide-Type Room-Temperature Ionic Liquids
Authors: Fukuta Rie , Katayama Yasushi , Miura Takashi
Published: October 2007

The hydrogen (H2) electrode reactions were investigated in three kinds of imide-type ionic liquids having 1-n-butyl-1-methylpyrrolidinium (BMP+), trimethy-n-hexylammonium (TMHA+) and 1-ethyl-3-methylimidazolium (EMI+) as cations. The diffusion coefficient and solubility of H2 were determined by chronoamperometric technique using both macro- and ultramicro-disk electrodes. The diffusion coefficient of HTFSI was also examined by dissolving bis(trifluoromethylsulfonyl)imide acid (HTFSI) in the ionic liquids. The solubility of H2 was nearly constant in each system within the temperature range from 25 to 70 {degree sign}C. The difference in the solubility of H2 may be explained by the difference in the free volume estimated from the density and the molar volume of ions. The order of the diffusion coefficients of H2 and HTFSI in each system indicates that the viscosity is a dominant factor on the diffusion process of HTFSI, while the diffusion of H2 is not affected by the viscosity.
Electrode Kinetics of Some Iron Complexes in an Imide-type Room-temperature Ionic Liquid
Authors: Tachikawa Naoki , Katayama Yasushi , Miura Takashi
Published: October 2007

The electrode kinetics of Fe(bpy)33+/Fe(bpy)32+ (bpy = 2,2'-bipyridine), FeCp2+/FeCp2 (Cp- = cyclopentadienyl), FeCl4-/FeCl42- and Fe(CN)63-/Fe(CN)64- on a platinum electrode were investigated over the temperature range from 25 to 60 {degree sign}C in a room-temperature ionic liquid, 1-n-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI). The average activation energy for the diffusion coefficients of these complexes was ~ 20 kJ mol-1, which was close to the activation energy for the viscosity of BMPTFSI. The diffusion coefficients of these complexes were found to be affected not only by the viscosity of BMPTFSI but also by the charge of the complexes. On the other hand, the heterogeneous rate constants of these redox reactions were estimated to be ~ 10-4 cm s-1 by electrochemical impedance spectroscopy. The apparent heterogeneous rate constants of Fe(bpy)33+/Fe(bpy)32+, FeCp2+/FeCp2 and Fe(CN)63-/Fe(CN)64- were smaller than those in other conventional solvents.
Thermodynamics of the Formation of Vanadium(II) Complexes in Chloride Melts
Authors: Polovov Ilya B. , Vasin Boris D. D. , Abakumov Anton V. V. , Rebrin Oleg I. I. , Chernyshov Mikhail V. V. , Volkovich Vladimir A. , Griffiths Trevor R. R.
Published: October 2007

Vanadium equilibrium potentials were determined in NaCl-KCl equimolar melts containing 0.018 - 8.02 wt.% of vanadium between 690 and 820 oC. It was found that only vanadium(II) ions are present in the equilibrium with the metal. The temperature dependence of E*V2+/V formal standard potential was determined. Enthalpy and entropy change of the formation of vanadium(II) chloride in NaCl-KCl melt were determined. Hypothetical values of enthalpy and entropy change of the formation of super-cooled liquid vanadium(II) chloride were calculated. Enthalpy and entropy of mixing of VCl2 and NaCl-KCl were estimated.
Electrochemical Behavior of Sulphur Species in Molten Chlorides
Authors: Hajasova Jana , Haarberg Geir Martin , Martinez Ana Maria
Published: October 2007

Sulphur is one of the quantitatively very important impurities in the Hall-Héroult process of aluminium production. Because sulphur leaves the cell as gaseous SO2, H2S, COS and CS2, it has impact on the environment. This work is focused on the characterization of the electrochemical behaviour of sulphur species in molten chlorides and should contribute to a better understanding of sulphur behaviour in such systems. The behaviour of sulphur (added in the form of sulphate, sulphide and sulphite) was studied using cyclic voltammetry, chronoamperometry and square wave voltammetry. Electrochemistry of sulphur species was found to be rather complex, depending mostly on the base electrolyte composition.