bluuebunny/crossref_metadata_2025_split huggingface dataset:
Realization of Highly Controllable Electrolysis Process by Application of Carbon NanoTubes in Field Effect Transistors
Authors: Naghsh Nilchi Jalal , Mohajerzadeh Shamsoddin 
Published: August 2010

AbstractWe have proposed, fabricated and tested a novel structure of Field-Effect Transistor (FET) combined with carbon nanotubes (CNT) to control the process of electrolysis. Our proposed device includes a conventional n-channel MOSFET, with a selective growth of carbon nanotubes in its drain region. MOSFET is made according to standard NMOS fabrication flow chart utilizing the advantage of a self-aligned process. The CNT growth is carried out in plasma and at a high temperature environment, so a thick layer of chromium (200nm) was deposited on the whole structure as a passivating layer to overcome MOSFET degradation caused by dopant escape. Afterward we deposited and patterned a thin layer of nickel (10nm) as the catalyst of CNT growth. The CNTs are grown in a DC-PECVD system. Following this step, we etched away the chromium layer completely. After the growth, the transistors needed an annealing treatment in Argon chamber at 500°C for 5 hours to retrieve their electrical behavior. We believe this happens because the atomic hydrogen can pass through the chromium layer and passivate the impurities and annealing in Argon chamber give them enough energy to leave the silicon.In this structure, the CNT collection is used as one-side electrode of electrolysis and the MOSFET acts as the current controller. We tested the structure to electrolyze a one molar mixture of water and salt and observed well-controlled current-voltage characteristics.
Vertical Aligned CNT Growth on Metals for Direct Use With Electrical Conductance
Authors: Kim Jin-Ju , Lee Byeong-Joo , Jeong Goo-Hwan 
Published: August 2010

AbstractWe present growth of vertically aligned carbon nanotube (VCNT) on metal substrates such as Cu foils, Inconel 600 and stainless steel (SUS316L) using thermal chemical vapor deposition (TCVD) in order to get a low contact resistance at interface between CNT and substrates for future applications. The temperature range for VCNT growth was 700-775 °C and mixtures of acetylene, argon and hydrogen were used as processing gas. The tube length was controlled by growth time and temperature. Finally, we successfully grew the VCNT on Cu foils over 1 cm2 and confirmed the excellent electrical conductance which can be directly used as anodic electrode in lithium ion battery. On the other hand, the growth of VCNT on Inconel 600 or SUS316L sheets was carried out as purchased. These tubes are expected to be useful for field emission devices.
Low-temperature Wet Chemical Deposition of Ultra-thin ZnS/ZnO Bilayers on Plastic Substrates for Applications of Photovoltaic Devices
Authors: Louh Rong-Fuh , Wu William , Liu Jean , Tsai Irene 
Published: August 2010

AbstractThe ultra-thin II-VI semiconductor ZnS/ZnO bilayers (< 50 nm thickness for each layer) can be easily formed on the plastic substrates at 70˜80°C for 20 min. By low temperature wet chemical synthesis techniques, namely chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR). The specific microstructure of such ZnS/ZnO bilayers including film thickness, particle size and morphology, is also modified and obtained in accordance with processing parameters. Along with thin film quality and morphology, the transmittance and reflectance of ZnS/ZnO layers can be measured by field emission SEM and UV-Vis spectroscopy. Besides the bilayer of ZnS (˜35 nm thick)/ZnO (˜50 nm thick) film with uniform thickness was successfully deposited on the optical grade PET substrates, a well-distributed layer of ZnO nanoparticles with ˜100 nm size on the top of ZnS (35 nm thick) film was also attempted. The average transmittance of these bilayer samples can reach greater 85%. Our future goal is to employ such ZnS/ZnO bilayer structure on potential organic substrates to be associated with flexible photovoltaic devices to meet desired cost-effectiveness requirements.
TiO2/Dye/Electrolyte Interface Engineering by Atomic Layer Deposited Ultra Thin SiO2 for Improved Dye Sensitized Solar Cell Performance
Authors: Shanmugam Mariyappan , Bills Braden , Farrokh Baroughi Mahdi 
Published: August 2010

AbstractThe short circuit density (JSC) and open circuit voltage (VOC) of dye sensitized solar cells (DSSCs) were improved from 9.8 to 17.8 mA/cm2 and 728 to 743 mV by depositing an ultra thin SiO2 layer on mesoporous TiO2 using Atomic Layer Deposition (ALD) method. X ray photoelectron spectroscopy confirmed the growth of SiO2 on mesoporous TiO2 surface. It was also observed that the enhancement in DSSC performance highly depends on the thickness of the ALD grown SiO2 layers on mesoporous TiO2. Compared to the reference DSSC which used untreated TiO2, incorporation of 5 ALD cycles (about 5 atomic layers) of SiO2 on mesoporous TiO2 resulted in 80 % enhancement (E) in the photoconversion efficiency from 4 to 7.2%. It is believed that the deposition of the ultra thin SiO2 film on mesoporous TiO2 modifies the density and activity of the surface states and an optimized layer thickness (5 cycles) leads to significant improvement in the DSSC performance. The enhanced photovoltaic performance was confirmed by dark and illuminated I-V and external quantum efficiency (EQE) measurements.
Phonon density of states of model ferroelectrics
Authors: Choudhury Narayani , Kolesnikov Alexander I , Schober Helmut , Walter Eric J , Johnson Mark , Abernathy Douglas , Lucas Matthew S 
Published: August 2010

AbstractFirst principles density functional calculations and inelastic neutron scattering measurements have been used to study the variations of the phonon density of states of PbTiO3 and SrTiO3 as a function of temperature. The phonon spectra of the quantum paraelectric SrTiO3 is found to be fundamentally distinct from those of ferroelectric PbTiO3 and BaTiO3. SrTiO3 has a large 70-90 meV phonon band-gap in both the low temperature antiferrodistortive tetragonal phase and in the high temperature cubic phase.Key bonding changes in these perovskites lead to spectacular differences in their observed phonon density of states.
Ex-situ and in-situ Neutron Radiography Investigations of the Hydrogen Uptake of Nuclear Fuel Cladding Materials During Steam Oxidation at 1000°C and Above
Authors: Grosse Mirco , van den Berg Marius , Lehmann Eberhard Helmar , Schillinger Burkhard 
Published: August 2010

AbstractNeutron radiography is a powerful tool for the investigation of the hydrogen uptake of zirconium alloys. It is fast, fully quantitative, non-destructive and provides a spatial resolution of 30 μm. The non-destructive character of neutron radiography provides the possibility of in-situ investigations. The paper describes the calibration of the method and delivers results of ex-situ measurements of the hydrogen concentration distribution after steam oxidation, as well as in-situ experiments of hydrogen diffusion in β-Zr and in-situ investigations of the hydrogen uptake during steam oxidation.
Real-time and Direct Observation of Hydrogen Absorption Dynamics for Pd Nanoparticles
Authors: Matsumura Daiju , Okajima Yuka , Nishihata Yasuo , Mizuki Jun'ichiro 
Published: August 2010

AbstractDynamic local structural change of Pd nanoparticles on alumina surface during hydrogen absorption process was directly observed by x-ray absorption fine structure spectroscopy with dispersive mode. Main four parameters of x-ray absorption spectroscopy were determined even in the case of 50 Hz observation. It is clearly revealed that Pd nanoparticles directly change to the hydride phase in 50 ms at 200 kPa of hydrogen pressure. Although large lattice expansion was observed, significant structural distortion was not investigated in the results of the change of Debye-Waller factor.
Organic Heterojunctions for Photovoltaic Applications: C60 Growth on Pentacene
Authors: Cantrell Rebecca Ann , Clancy Paulette 
Published: August 2010

AbstractUsing atomic-scale Molecular Dynamics (MD) and energy minimization techniques in conjunction with semi-empirical MM3 potential energy functions, we consider the adsorption of a C60 molecule on a series of hypothetical pentacene structures that vary only in the tilt of the angle that the short axis of the pentacene molecules makes with the underlying surface (the long axis lying essentially flat, as on a metal substrate). Important relationships were discovered between the angle adopted by the short axis of pentacene on the surface, φ1, and the adsorption and diffusion characteristics of C60. Static energy calculations show that there is a transition of the deepest energy minima from between the pentacene rows at low values of φ1 to within the rows at high values of φ1, where φ1 is the angle the pentacene short axis makes with the surface. MD confirms this trend by the predominant residence locations at the extreme φ1 values. Furthermore, MD results suggest that the C60 traverses the pentacene surface in the east-west direction for lower φ1 values (φ1 ≤ 40°) and in the north-south direction for higher φ1 values (φ1 ≥ 70°). Taking both static and dynamic results together, the most favorable tilt angles for mono-directional nanowire growth should occur between 70° and 80° off-normal.
Steam and Air Oxidation Behavior of Nuclear Fuel Claddings at Severe Accident Conditions
Authors: Große Mirco , Steinbrück Martin , Stuckert Juri 
Published: August 2010

AbstractThe oxidation behavior of zirconium alloys used as materials for nuclear fuel rod claddings is investigated in the temperature range between 973 and 1673 K in steam and air atmosphere. Parabolic kinetics was found for all materials, atmospheres and temperatures, at least at beginning of the reactions. The temperature dependence of the reaction rate is of Arrhenius type. The parameters of the Arrhenius functions are determined and given for steam oxidation. Due to the formation of a large amount of cracks an acceleration of the reactions can occur. Reasons of the crack formations are phase transformations in the oxide layer known as the breakaway effect and, in case of air atmosphere, local oxygen starvation conditions resulting in reactions with nitrogen. The paper gives a short overview of the relevant mechanisms and processes.
Evolution of Static Physical Properties in Plutonium by Self-irradiation Damage
Authors: Chung Brandon W , Lema Kenneth , Hiromoto David 
Published: August 2010

AbstractThe alpha-decay of plutonium leads to the age-related change in physical properties. This paper presents updated results of age-related effects on enriched and reference alloys measured from immersion density, dilatometry, and mechanical tests. After nearly 100 equivalent years of aging, both the immersion density and dilatometry show that the enriched alloys are decreasing in density by less than 0.002% per year and now exhibit a near linear density decrease, without void swelling. The tensile tests show that the aging process increases the strength of plutonium alloys, followed by possible saturation past 70 equivalent years of age. The ultimate goal of this work is to develop capabilities to predict physical properties changed by aging effects.
The pressure-temperature phase diagram of URu2Si2 under hydrostatic conditions
Authors: Butch Nicholas Patrick , Jeffries Jason R. , Evans William J. , Chi Song Xue J. , Leao Juscelino B. , Lynn Jeffrey W , Sinogeikin Stanislav V. , Hamlin James J. , Zocco Diego A. , Maple M. Brian 
Published: August 2010

AbstractThe pressure dependence of the hidden order phase of the heavy fermion superconductor URu2Si2 has been a subject of intense research since shortly after the discovery of the compound decades ago. Applied pressure increases the critical temperature of the paramagnetic / hidden order transition and brings about a transition to long-range antiferromagnetism. The reported pressures and temperatures of these phase boundaries vary between studies: 4 – 7 kbar at low temperature and 12 – 15 kbar at high temperature. We review experimental evidence that the measured values of pressure and temperature are very sensitive to the chosen pressure transmitting medium. Recent x-ray diffraction measurements suggest that the relative position of the silicon atom in the unit cell is changing as a function of pressure. Recent neutron diffraction measurements show that the zero-temperature limit of the hidden order / antiferromagnetic transition occurs at pressures greater than 7.5 kbar.
Fuel Cycle Research and Development Program, Used Fuel Disposition Campaign Objective, Mission, Plans, and Activity Status
Authors: Nutt William Mark , Peters Mark , Swift Peter , McMahon Kevin , Sorenson Ken , Schwab Patrick 
Published: August 2010

AbstractThe safe management and disposition of used nuclear fuel and/or high level nuclear waste is a fundamental aspect of the nuclear fuel cycle. The United States currently utilizes a once-through fuel cycle where used nuclear fuel is stored on-site in either wet pools or in dry storage systems with ultimate disposal in a deep mined geologic repository envisioned. However, a decision not to use the proposed Yucca Mountain Repository will result in longer interim storage at reactor sites than previously planned. In addition, alternatives to the once-through fuel cycle are being considered and a variety of options are being explored under the U.S. Department of Energy's Fuel Cycle Research and Development Program.These two factors lead to the need to develop a credible strategy for managing radioactive wastes from any future nuclear fuel cycle in order to provide acceptable disposition pathways for all wastes regardless of transmutation system technology, fuel reprocessing scheme(s), and/or the selected fuel cycle. These disposition paths will involve both the storing of radioactive material for some period of time and the ultimate disposal of radioactive waste.To address the challenges associated with waste management, the DOE Office of Nuclear Energy established the Used Fuel Disposition Campaign within its Fuel Cycle Research and Development Program in the summer of 2009. The mission of the Used Fuel Disposition Campaign is to identify alternatives and conduct scientific research and technology development to enable storage and disposal of used nuclear fuel and wastes generated by existing and future nuclear fuel cycles. The near-and long-term objectives of the Fuel Cycle Research and Development Program and it's Used Fuel Disposition Campaign are presented.
Structural and Crystallization Study of a Simplified Aluminoborosilicate Nuclear Glass Containing Rare-earths: Effect of ZrO2 Concentration
Authors: Caurant Daniel , Quintas Arnaud , Majerus Odile , Loiseau Pascal , Charpentier Thibault , Vermaut Philippe , Dussossoy Jean-Luc 
Published: August 2010

AbstractZirconium is an abundant element in nuclear wastes. In this paper, we present structural and crystallization results for a simplified glass composition belonging to the SiO2-Al2O3-B2O3-Na2O-CaO-ZrO2-RE2O3 system (RE = Nd or La) developed to immobilize highly concentrated waste solutions. The effect of varying ZrO2 content on the structure and the crystallization tendency of this glass was studied using a multi-spectroscopic approach. Zr was shown to be located in six-fold coordinated sites whose charge compensation seems preferentially insured by Na+ cations. Whereas a significant decrease of the proportion of BO4 units was observed with ZrO2 content, no effect was detected on the environment of AlO4 units. However, a significant structural evolution of the silicate network occurred due to the formation of Si-O-Zr bonds. Whatever ZrO2 concentration, the crystallization of only a rare earth silicate apatite phase was observed during either slow cooling from the melt or isothermal heat treatment. Whereas nucleation mainly occurred from the surface of the glass without ZrO2, the introduction of zirconium induced apatite crystallization in the bulk. It is proposed that this nucleating effect of ZrO2 is mainly due to changes induced in the neighborhood of Nd3+ cations in glass structure.
New Lanthanide Oxalato-nitrates Crystallized From Acidic Solutions
Authors: Tamain Christelle , Rivenet Murielle , Arab-Chapelet Bénédicte , Grandjean Stéphane , Abraham Francis 
Published: August 2010

AbstractTo identify the various oxalates and oxalato-nitrates likely to form during the nuclear fuel reprocessing we study crystallization of such compounds by various methods (slow diffusion, hydrothermal syntheses, in situ oxalate syntheses …), in different conditions and in presence of monovalent ions. In a first stage, lanthanides are used as surrogates of the actinides (III) radioactive elements. This communication reviews various lanthanides (III) compounds obtained by crystallization from nitric acid solution containing hydrazinium ions. Diethyl oxalate was used as a precursor for oxalate ions. A careful adjustment of the experimental conditions allowed us to synthesize single crystals of nitrates, oxalato-nitrates and oxalates with various ligand/Ln(III) ratio and containing nitrates as ligands or as counter ions. In all the compounds hydrazinium ions are present as counter ions. The crystal growth method is described and the crystal structures, determined by X-ray diffraction from single crystals, are discussed in terms of metal-oxalate frameworks.
Effect of Ionic Strength on the Stability of Colloids Released from Injection Grout Silica Sol
Authors: Holtta Pirkko L , Lahtinen Mari , Hakanen Martti , Lehto Jukka , Juhola Piia 
Published: August 2010

AbstractIn Olkiluoto Finland colloidal silica called silica sol (EKA Chemicals) will be used as a non-cementitious grout for the sealing of fractures of the hydraulic apertures of 0.05 mm or less. The use of colloidal material has to be considered in the long-term safety assessment of a spent nuclear fuel repository. The potential relevance of colloid-mediated radionuclide transport is highly dependent on their stability in different geochemical environments. Objective of this work was to study the effect of ionic strength on stability of silica colloids released from silica gel. Silica gel samples were stored in contact with NaCl and CaCl2electrolyte solutions and in deionized water. Colloid release and stability were followed for two years by taking the samples after one month and then twice in a year. The release and stability of colloids were followed by measuring particle size, colloidal silica concentrations and zeta potential. The particle size distributions were determined applying the dynamic light scattering (DLS) method and zeta potential based on dynamic electrophoretic mobility.In dilute NaCl (10-7–10-2M) and CaCl2(3 10-7– 3 10-3M) solutions, a mean colloid diameter was less than 100 nm and high negative zeta potential values suggests the existence of stable silica colloids. After two years, the mean particle diameter was increased but it was still less than 500 nm and absolute value of zeta potential was decreased. In 0.1–1 M NaCl and 0.03–3 M CaCl2solutions, wide particle size distribution and zeta potential values around zero suggested particle aggregation and instable colloids. In deionized water, particle size remained rather stable and zeta potential remained high negative suggests stable silica colloids. The threshold value of ionic strength was 0.03–0.1 M when salinity had an effect on the stability of colloids. In Olkiluoto, the ionic strength of saline groundwater is order of magnitude higher than the range of effect value obtained in this study. Under the prevailing conditions in Olkiluoto, silica colloids are instable, but the possible influence of glacial melt waters has to be considered.
Effect of Molybdenum and Ruthenium on the Crystallization Tendency of a New Nuclear Glass Containing High Rare-earth Concentration
Authors: Caurant Daniel , Chouard Nolwenn , Majerus Odile , Dussossoy Jean-Luc , Ledieu Aurelien , Klimin Sergey , Pytalev Dmitry 
Published: August 2010

AbstractThe impact of Nd2O3, MoO3 and RuO2 addition on the competition between the crystallization of apatite Ca2Nd8(SiO4)6O2 and powellite CaMoO4 phases which both may appear in High Level Waste nuclear glass (under certain specific conditions of cooling and glass composition) has been studied on a simplified composition belonging to the system SiO2-Na2O-CaO-Al2O3-B2O3. X-ray diffraction (at room temperature and high temperature) and scanning electron microscopy measurements have been performed on five glasses under two different thermal treatments. We show that RuO2 acts as a nucleating agent for apatite. Moreover, neodymium and molybdenum cations seem to be very close in the glassy network as Nd2O3 addition stops the phase separation of molybdates and inhibits the crystallization of CaMoO4. On the contrary, MoO3 seems to favor the crystallization of apatite. For several samples, the evolution of the distribution of Nd3+ cations after crystallization was followed by optical absorption spectroscopy.
The Fate of Radiogenic Iodine During the Electrochemical Treatment of Spent EBR-II Fuel
Authors: Frank Steven , Vaden DeeEarl , Westphal Brian R , Johnson Thomas A , Hahn Paula A , Giglio Jeff J. , Cummings Daniel G. , Rodriquez Michael 
Published: August 2010

AbstractRadiogenic iodine is one of the more difficult fission products to capture and immobilize during the reprocessing of spent nuclear fuel.However, for metallic fuels reprocessed by electrometallurgical treatment, it is believed that the majority of fission-product iodine is retained during the various processing steps. Spent fuel from the Experimental Breeder Reactor II (EBR-II) at the Idaho National Laboratory (INL) is being treated by a combination of electrochemical and pyrometallurgical methods to deactivate the bond sodium of the fuel, recover uranium, and immobilize fission products for disposal. This paper discusses the progress of various strategies and experiments to confirm the expected retention of iodine during the electrometallurgical treatment of EBR-II spent fuel. This includes surveys of previous observations and measurements, and the direct measurement of iodine from various process samples. Current measurements are aimed at iodine determination in the bond sodium and plenum regions of the fuel, refined iodine measurements in electrorefiner salt, and the retention of iodine during waste form production.
Coated Magnetic Nanoparticles for Acidic Nuclear Waste Separation
Authors: Kaur Maninder , Han Hongmei , Johnson Andrew , Kaczor Jesof , Paszczynski Andrzej , Qiang You 
Published: August 2010

AbstractActinide specific chelator (che) conjugated with magnetic nanoparticles (MNPs) have been developed to separate nuclear waste in acidic conditions. Compared to the traditional nuclear waste treatments, such as solvent extraction and ion exchange, this method is a simple, compact and cost-effective process that generates minimum secondary waste. In this paper, we focus on the coating process of MNPs to achieve a combination of good acidic resistance, high chelator loading density and efficient magnetic separation. An optimized silica coating process before conjugates chelator directly onto MNPs significantly improves the acidic resistance of the MNP-che complex. Chelator loading density is significantly increased by attaching a linear polyamine polymer poly(allylamine hydrochloride) (PAH) to the surface of the MNPs using chemical and physical approaches.