bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supernatant Treatment Considerations for the Neutralized Waste at West Valley
Authors: Gockley G. B. , Lahoda E. J. , Pope J. M. 
Published: March 2011

ABSTRACTThe neutralized high-level waste, stored at the Western New York Nuclear Service Center in West Valley, New York, was produced during the operation of the Nuclear Fuel Service, Inc. commercial nuclear fuel reprocessing plant. The supernatant is a highly concentrated salt solution (NaNO3 , NaOH, Na2SO4 and NaCl) containing essentially all of the dissolved cesium as the primary radioactive component. The sludge is primarily iron and aluminum hydroxides and contains strontium and the bulk of the long-lived isotopes. The supernatant will be treated to remove essentially all of the radioactivity and then be concentrated and disposed of as low level nuclear waste. The following supernatant treatment considerations have been evaluated on a laboratory scale using simulated West Valley waste: 1) Organic ion exchange resins; 2) Inorganic ion exchange media; 3) In-tank processing. These processes will be described and preliminary laboratory data will be presented.
Corrosion Resistant Canisters for Nuclear Waste Isolation
Authors: Magnani Nicholas J. 
Published: March 2011

ABSTRACTCorrosion resistant canisters are an important component of the engineered barriers of a nuclear waste disposal system. In addition to providing containment for the waste form during transportation and emplacement, a durable canister can eliminate hydrothermal interactions with the waste form. The selection of a repository site and emplacement technique will affect canister design and could also impact material selection. While there are still many issues to be resolved, there are two different concepts being evaluated to provide durable canisters for waste disposal: (1) canisters fabricated out of extremely corrosion resistant materials such as Ti-base or Ni-base alloys, and (2) canisters fabricated out of less durable materials but designed with a corrosion allowance. Each of these types of canisters could fail to meet the design objectives through a variety of failure processes. The more important of these are discussed.
Investigations of Suitable Metallic Container Materials for Haw Solidification
Authors: Mirschinka Volker , Halaszovich Stefan , Odoj Reinhard , Forch Ursula , Forch Karl 
Published: March 2011

ABSTRACTThe influence of the main alloying elements of six different steels and high temperature resistant alloys for crucibles containing HAW glass on the homogeneity of the waste glass was investigated. The distributions of iron, chromium, nickel, and cobalt were studied by an electron beam microprobe. The results are given and discussed.
Thermal Conductivity of Waste Forms and Geologic Media
Authors: Pohl R. O. , Vandersande J. W. 
Published: March 2011

ABSTRACTIn order to predict the range of thermal conductivities to be expected in waste forms and in geologic media, an understanding of the pertinent phonon scattering processes is required. It has been shown that grain boundaries in polycrystalline media are unimportant at low temperatures relative to lamellae which arise from twinning, exsolution, or foreign inclusions within the grains. The possible role of lamellar structures on the conductivity at high temperatures will be discussed.
Hydrothermal Simulation of Ion Migration in Selected Argillaceous Sediments: Implications For Backfill Design
Authors: Bratton Lisa , Scheetz Barry E. , White William B. 
Published: March 2011

ABSTRACTArgillaceous rocks, used either as a repository rock or as a backfill material provide a reactive medium with which escaped radionuclides can react. Solutions containing U, Nd Gd, Cs, and Sr were reacted with bulk specimens of two argillites with the objective of determining penetration of heavy metals into the rock, and the reaction products. The two Devonian argillites were chosen to represent a highly reducing rock containing pyrite and carbonaceous material as accessory minerals, and a clean, alumino-silicate rock containing mainly quartz and layer silicates. Cylinders of rock were reacted with solutions at saturated steam pressures and 200°C.At the end of the runs, both rocks contained reduced uranium in the form of U02.25. The rare earths were associated with the uranium. There was a precipitated coating of uranium-rich material on the outside of the reducing shale and few of the radionuclides had penetrated the interior. Uranium also formed a precipitate within 0.5 mm of the surface of the oxidized shale leaving a depleted zone near the surface. Cesium and strontium did not penetrate the reducing shale but were uniformly distributed throughout the oxidized shale. Chlorite, apatite and pyrite were found to be the most reactive phases in the shales.
γ-Zirconium Phosphate as a Cs-Waste form for Partitioned Wastes
Authors: Komarneni Sridhar , Roy Rustum 
Published: March 2011

ABSTRACTγ-zirconium phosphate (γ-ZrP), γ-Zr(HPO4)2 2H2O is an extremely selective cesium ion sieve for nuclear waste solutions. Because of its layer structure, the adsorbed Cs can be directly fixed in γ-ZrP by collapsing the layers upon heat treatment. Fixation of 96 and 98% of the adsorbed Cs was achieved by simple heat treatment at 350°C and 600°C respectively. Thus, heat treatment of this γ-ZrP leads to a good radiophase with good leach resistance. Cs sorbed γ-ZrP can also be converted to CsZr2(PO4)3 [;sodium zirconium phosphate (NZP) radiophase] by sintering with ammonium monobasic phosphate and zirconyl nitrate at about 850°C. Thus, γ-ZrP serves as a precursor to CsZr2(PO4)3 radiophase which has comparable leach resistance to other phases under consideration for radio-Cs immobilization.
Diffusion Measurements in Concrete and Compacted Bentonite
Authors: Muurinen A. , Rantanen J. , Ovaskainen R. , Heinonen O.J. 
Published: March 2011

ABSTRACTA laboratory method for measurement of diffusion of radionuclides inconcretes and compacted bentonite has been developed. In this method a tracer is introduced through one end into the cylindrical sample closed in a tube and preequilibrated with water. After the introduction period of the tracer the tube is sealed hermetically and the concentration profiles of the radionuclides are measured periodically from the outside of the sample using a collimated detector. Diffusivities are calculated from the activity profiles by fitting the theoretical curve with the measured profile. The paper will give diffusion data for Co, Sr and Cs in some concrete products and for Co and Cs in compacted sodium bentonite.
Compatibility Relationships in the U-Fe-O(-H) System at 400°C: The Implications of the Ferric-Ferrous Buffer for the Immobilization of Uranium and Transuranic Elements
Authors: Smith Deane K. , Phelps Freeborn W. , Scheetz Barry E. 
Published: March 2011

ABSTRACTThe current strategy for the immobilization of nuclear wastes is based upon a system of multiply redundant barriers for which geological containment is the final barrier to the migration of radionuclides in the biosphere. The ability of the respository host rock to buffer the oxygen fugacity of the pore waters is a critical concern for the evaluation of the far-field migration of selected elements; notable Tc, U and TRU elements. The buffer capacity of all proposed host rocks, with the exception of salt, is based upon the presence of both ferric and ferrous iron in the host rock phases.The system U-Fe-O(-H) was selected for study because of its significance on the role of Fe in controlling the oxidation state of the U. It has been established that the Fe2+/Fe3+ couple is the controlling factor in limiting the uranium oxidation to the U4+ state.The results from this experimental study at 400° C (the maximum worse case temperature for a repository) verified the existence of the compatibility triangles between hematite and UO2.00 and magnetite and between U4O9 and UO2.00 and hematite. These data indicate that in the presence both ferric and ferrous ions, the form of the uranium dioxide is retained as stoichiometric UO2.00 and not as an intermediate member of the UO2+x solid solution series or other higher oxide. These experimental results are in concert with the phase relationships predicted by Freeborn et al. (1980) based upon thermochemical calculations.
Laser Irradiation of InSb:Ge Thin Films
Authors: Rubin K. A. , Ortiz C. , Solis J. , Roche K. 
Published: March 2011

ABSTRACTThe effect of 647nm Kr-ion laser and 514.5 nm Ar-ion irradiation on 1 and 7 μm diameter regions, respectively, of (In43Sb57)87 Ge13 thin alloy films was determined. Laser irradiation times of 50ns - 20μs produce different reflectivity states. An amorphous state of increased reflectivity with respect to the as-deposited amorphous state was produced only with the smaller beam after short pulse (∼100ns to ∼500ns) laser irradiation. Slightly longer pulses caused formation of surface corrugations. The corrugation morphology occurred in the nanosecond regime both in air and vacuum. Further laser annealing caused crystallization and decreased reflectivity. The crystallization microstructures were random cellular for the irradiation in air. Irradiation in vacuum produced three, distinct concentric structures.
Deposition of Dielectric Optical Coatings: A Microstructural Study of the Deposited Layers and Interfaces
Authors: McCarthy J. M. , Thomas L. E. , Pawlewicz W. T. , Frydrych W. S. , Exarhos G. J. 
Published: March 2011

ABSTRACTThin dielectric films for optical applications are deposited on substrates using a variety of techniques including reactive sputtering, solgel reaction, and ion assisted plasma deposition. This transmission electron microscopy study characterizes optical coatings produced by the above deposition techniques and shows how changes in deposition conditions change microstructure and as a result the optical properties.
Laser Assisted Photodeposition of Gold on Semiconducting Material
Authors: Joshi N. V. , Quintero P. , Galindo H. , de Joshi Virginia Otero 
Published: March 2011

ABSTRACTRecently, much interest has been created in laser driven chemical reactions and their application towards photodeposition of thin films of metals on semiconducting substrates. The next logical step is to verify the capability of this technique in making adequate electrical contacts for microelectronic fabrications and for circuit writing. Some work in this direction has been reported for Iron and Tungsten. However, deposition of gold has not been reported so far, even though it is very significant from the technological point of view. Therefore, we are proposing here a method for photodeposition of gold.this pupose, Pyridine gold (III) trichloride was found to be adequated and it was prepared by a conventional method, then dried under vacuum for 48 hours. A concentrated solution was made by dissolving it in Dimethyl sulfoxide. A tiny drop of it was put on the substrate and exposed to radiation 488 nm, obtained from an argon ion laser. The time of photodeposition depends upon the power of the beam; for 2 watt/mm2 and for four to six minutes of continuous exposure, good, low noise, reliable and nearly ohmic contacts were obtained.The method is found to be suitable for both conventional and non conventional semiconductors such as ZnTe, doped and undoped ZnSe, and diluted magnetic semiconductors such as Zn1−xMnxSe for which normally used methods are not applicable. The present technique can also be extended to the hiqh Tc superconductor YBa2Cu3O7. The possible mechanism of photodeposition is also discussed.
Optical Waveguides in GaAs/AlGaAs MQW Structures Formed by Silicon Induced Quantum Well Mixing
Authors: Wismayer A. C. , Weiss B. L. , Roberts J. S. 
Published: March 2011

ABSTRACTSi implantation followed by furnace annealing has been used to produce the mixing of GaAs/AlGaAs multiquantum well (MQW) structures grown by MOVPE. Masked implants have been used to fabricate stripe optical waveguides. Results are presented here for the effect of the ion dose and the annealing time and it is shown that complete mixing occurs for a 1015 cm−2 dose of 500 keV Si+ after annealing at 750 °C for two hours. Waveguides fabricated using this process showed a minimum TE mode propagation loss of 33 dB cm−1 at a wavelength of 1.15 μm.
Microstructural development during Fabrication of Ti:LiNbC3 Optical Waveguides
Authors: McCoy M. A. , Dregia S. A. , Lee W. E. , Sanford N. A. 
Published: March 2011

ABSTRACTThe microstructural development of Ti:LiNbO3 optical waveguides as a function of annealing time and temperature was studied using transmission electron microscopy. The morphological evolution of the deposited Ti film can be characterized by three stages: (i) oxidation beginning at low temperatures, (ii) coarsening and secondary grain growth of the oxide film at higher temperatures and (iii) eventual film breakup and void formation. Secondary grain growth is driven by minimization of interfacial energy of grains which have a special epitaxial relationship with respect to the LiNbO3 substrate.
A Comparative Study of Electron Beam Deposited and Sputtered 7059 Corning Glass Thin Films for Waveguides
Authors: Gupta Mool C. 
Published: March 2011

ABSTRACTLow optical loss (<dB/cm) thin films of Corning 7059 glass have been prepared by electron beam deposition and by rf magnetron sputtering. The effects of gas pressure, deposition power and oxygen-to-argon ratio on refractive index and optical loss were studied. Deposition rates obtained with the sputtering process were about 0.2 nm/sec while much higher deposition rates (2 nm/sec) were obtained with electron beam deposition. The films were found to be amorphous in structure. The refractive index of electron beam-deposited films was measured as 1.50 while the sputtered film index was measured as 1.525. Film composition and composition profiles determined by RBS, electron microprobe and neutron activation analysis are presented. Sputtered films show uniform elemental composition profiles for Si, Ba, B and Al. Electron beam-deposited films have uniform composition profiles if the deposition power is kept constant. The rms surface roughness of the films, measured using an optical profilometer, is 1 nm. The contributions of surface roughness and cladding layer thickness to optical loss are discussed. The major source of optical loss in sputtered films is light absorption.
Synthesis and Characterization of Diamond-Like Carbon Films using Ion Beam Technique
Authors: Wu Richard L. C. 
Published: March 2011

ABSTRACTDiamond-like carbon (DLC) coatings have been deposited on several infrared transmitting substrates utilizing the ion beam deposition technique. Optimum deposition parameters have been established as a function of source gas composition, source pressure, ion-impact energy, substrate material and cleaning substrate procedures. Extensive characterization of the DLC films was also performed. Rutherford backscattering and proton recoil techniques were used to analyze carbon and hydrogen content and impurities. These films contain 70% atomic carbon and 30% atomic hydrogen. Transmission electron microscopy was used to analyze the crystallinity, void structure and surface microstructure, which were found to be amorphous and dense. Optical properties, such as refractive index and extinction coefficient, were measured using transmission/reflection spectroscopy, ellipsometry and laser calorimetry. Environmental testing was performed using various acids and solvents. The thermal stability and moisture penetration on these DLC films were extensively investigated. The effect of high ion energy radiation on DLC films was studied. Details of the preparation method and characterization of DLC films are presented.
Effect of Heteroatomic d10 Interactions on the Optical Properties of Cu+ Doped Ag+-ß″-Alumina
Authors: Barrie J. D. , Dunn B. , Stafsudd O. M. 
Published: March 2011

ABSTRACTThe optical properties of Cu+ doped Ag+-ß″-alumina are strongly affected by interactions between the d10 closed shell Cu+ and Ag+ ions. These effects can be distinguished from Cu+-Cu+ interactions previously observed in ß″-alumina, and produce a strong red emission upon ultraviolet excitation.
Characterization of Grain Boundaries and Interfaces by High Resolution Transmission Electron Microscopy
Authors: Krakow William 
Published: March 2011

AbstractSeveral examples will be given of high resolution electron microscope images of both grain boundaries and interfaces and the methods which have been applied to understanding their atomic structure. Specific expitaxial interfacial structures considered are: Pd2Si/Si used for ohmic contacts, Al on Si overlayers and CaF2/Si where the CaF2, is an attractive possibility as a dielectric material. For the case of grain boundaries specific examples of both twist and tilt boundaries in Au will be given to show the imaging capability with the new generation of medium voltage electron microscopes.
In-Situ Monitoring of the Initial Growth of a-C:H Films by AES
Authors: Tschersich K.G. 
Published: March 2011

AbstractAmorphous hydrogenated carbon films are deposited by direct ion beam deposition onto Si and W substrates at room temperature. Simultaneously, the sample surface composition is measured by Auger electron spectroscopy. The results indicate a sharp interface between film and Si and the formation of a W2C layer between film and W. The in-situ measurements are compared with sputter depth profiles. It is found that the former ones give insight into film growth processes, that is unattainable by sputter profiling.
Mechanical and Chemical Characterization of a Metal-Bioceramic Interface
Authors: Filiaggi Mark J. , Coombs N. A. , Pilliar R.M. 
Published: March 2011

AbstractPlasma sprayed Hydroxyapatite (HA) coatings are applied to metal prostheses to allow for implant fixation through chemical bonding of the coating with surrounding bone tissue. Without a well-adhering coating, this fixation is threatened. Thus, a thorough characterization of the metal / ceramic interface is necessary. This study used a novel composite short bar interfacial fracture toughness technique with high resolution electron spectroscopic imaging to examine Ti-6AI-4V plasma spray coated with 100μm of HA. For this system, an interfacial fracture toughness value of 1.31 +/− 0.08 MPa·m1/2 was obtained, with a corresponding tensile adhesive bond strength of 6.7 +/− 1.5 MPa. High resolution ESI revealed distinct phosphorous segregation to the interface and diffusion into the underlying titanium. A 24-hour post-heat treatment at 960°C greatly increased the bond strength at this interface. Observations from ESI suggested that this effect may be due to enhanced diffusion of both phosphorous and calcium into the metal substrate.
Microscopic Characterization of Cosintered Copper/Cordierite Interfaces
Authors: Werckmann J. , Han B.S. , Faerber J. , Humbert P. , Carriere B. , Esnouf C. , Chardon N. , Guille J. , Bernier J.C. 
Published: March 2011

AbstractCopper and sol-gel processed cordierite were cosintered in oxidizing atmosphere using an eutectic bonding technique. Firing at low and high heating rates leads to interfaces which present different macroscopic properties. These interfaces were therefore investigated on a microscopic scale by SEM, XPS and STEM analyses. Copper diffusion as well as strong chemical and structural modifications were observed in the interface region. Although these interfaces have good adhesion properties, there was no evidence for the formation of some interfacial copper compound.
Calculation of Local Elastic Constants at a Metallic Grain Boundary
Authors: Kluge M. D. , Lutsko J. F. , Wolf D. , Phillpot S. R. 
Published: March 2011

AbstractA new atomistic-simulation method for calculating the full local elastic-constant tensor in terms of local stress and local strain for inhomogeneous systems is described. Results of simulations of an isolated high-angle twist grain boundary are presented. A dramatic reduction in resistance to shear parallel to the grain boundary is observed, and its relation to structural disorder is discussed.
Dynamic Control of Water Concentration to Prolong The Life Time of Encapsulated Electronic Devices in High Humidity Environments
Authors: Kim I. U. , Troyk P. R. , Anderson J. E. 
Published: March 2011

AbstractSilicone resins and gels have been used extensively for IC protection. Reduction of interfacial moisture and ionic contamination is considered crucial to device reliability.The present research has revealed an interesting phenomenon. Prolonged lifetime was obtained for comb pattern samples using a non-conventional encapsulation method. In order to increase specimen sensitivity to interfacial moisture, samples were contaminated prior to encapsulation. Three groups of contaminated samples encapsulated with polysiloxane were produced. Group I was encapsulated with a polymer/CaCl2/polymer/substrate structure. The structure of group II consisted of only the polymer on the contaminated substrates. Group III was encapsulated with a CaCl2 embedded polymer/polymer /substrate structure. Following exposure at 85°C, 100−10 amperes after 2,000 hrs, with no visible corrosion. Group II and III samples showed visible corrosipn after 390 to 470 hrs with leakage current of the order of 10−5 amperes. Direct measurement of RH at the polymer/substrate interface and water sorption experiments were done to explain the mechanisms of these packaging structures.The experimental results suggest that a desiccating multilayer coating can maintain low interfacial water concentrations. During exposure to high external RH, water from the surroundings diffuses through the top layer, producing an interlayer consisting of a solid CaCl2 and a CaCl2-saturated solution. Until all of the salt dissolves, the water chemical potential of the saturated solution defines the water content at the polymer/substrate interface. Hence the RH at the polymer/substrate interface was maintained below that required to dissolve the residual surface contamination for a longer time than by conventional encapsulation. This technique could be useful to reduce the dependence of IC reliability upon pre-encapsulation cleaning.
Stress Measurement in Spin Coated Polyimide Films Using Time Average Holographic Interferometry
Authors: Maden Michele A. , Farris Richard J. 
Published: March 2011

AbstractIt is proposed that the stresses in a thin polyimide film can be analyzed using the solution to the problem of a vibrating membrane. The polyimide membrane is supported on a copper substrate and excited with a small speaker. The membrane vibrates uniformly in response to its resonant frequencies. The vibration pattern will be recorded using holographic interferometry. The biaxial stress in the film is calculated from the measured characteristic frequency, the density of the material, and the mode of vibration. This technique may also be used to determine the Poisson's ratio of the film by combining uniaxial and biaxial stress analyses.
Polyimides for Passivation of VLSI Circuits
Authors: Andel Maarten A. van , Gootzen Wil F.M. 
Published: March 2011

AbstractFrom a processing point of view polyimides are attractive materials for use as interlayer dielectric and as passivation coating on ICs. For plastic encapsulated devices they can also improve on the thermomechanics, thereby enhancing yield and reliability. We simulated the thermomechanical behaviour of such a device with finite element calculations. Based on these simulations the commercial product PIQ-L100 was chosen as a model polyimide to study some important physical and chemical parameters. The results from investigating internal stress, molecular orientation and imidization kinetics can be used to optimize polyimide processing and to obtain the desired coating characteristics.