bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiolytic Gas Generation and Oxygen Depletion in Ion Exchange Materials
Authors: Capolupo Wayne P. , James M.S. , Sheff R. 
Published: March 2011

ABSTRACTThe process of ion exchange is used extensively throughout numerous industries where water of extremely high purity is required. Government and commercial nuclear power facilities are typical of this, and have applied ion exchange processes for the removal of radioactive ions from aqueous solutions. When water is decontaminated in this fashion the ion exchange medium becomes saturated with the radioactive ions from solutions, and is then stored as radioactive waste in standard burial facilities. During this indefinite storage period, the chemical changes which occur in the ion exchange medium may result in oxygen depletion and gas generation within the storage vessel, and subsequent loss of integrity. It is the object of this work to investigate the early phases of radiolytic oxygen depletion and gas evolution through experimental procedure and observation. The results of this work will then be analyzed with respect to applications for the storage of radioactive ion exchange waste.
A Study of Coupled Thermomechanical, Thermohydrological and Hydromechanical Processes Associated with a Nuclear Waste Repository in a Fractured Rock Medium
Authors: Tsang C. F. , Noorishad J. , Wang J. S. Y. 
Published: March 2011

ABSTRACTIt has been recognized that coupled thermomechanical, thermohydrologic, and hydromechanical processes may play an important role in the behavior of the geologic formation around a nuclear waste repository. A numerical code, ROCMAS, was recently developed at Lawrence Berkeley Laboratory to calculate coupled heat transfer, fluid flow, and mechanical deformation in a fractured porous medium. Three scoping studies using this model are described in this paper, with the following preliminary conclusions. The thermomechanical simulations of a fractured rock mass show that the fractures can absorb the thermally induced rock deformations, thus possibly explaining the observed behavior of the granite rocks in the experiment at Stripa, Sweden. The variations in fracture aperture profiles in the hydromechanical simulations indicate that the rigid fracture assumptions used in most uncoupled studies may not be a good representation of fracture behavior. The thermohydromechanical model study reveals that perturbations induced by a heater may close a fracture near the heater borehole and stop the water inflow to the borehole.
Removal of Actinides From Waste Solutions by Ferrite Treatment
Authors: Boyd Thomas E. , Kochen Robert L. 
Published: March 2011

ABSTRACTFerrite treatment was found to be effective in removing actinides from Rocky Flats process waste solutions. With one ferrite treatment, plutonium concentrations were consistently reduced from around 10−4 g/l to between 10−7 and 10−8 g/l. Three to four grams of solids were produced per liter of solution treated as compared to 15.7 g/l observed for the flocculant precipitation technique now in use at Rocky Flats. Less cement was required for the immobilization of ferrite solids resulting in further reductions in waste generation. The success of ferrite treatment in laboratory studies has prompted serious consideration of this technique for implementation in plant operations.
Theoretical Predictions For Continuous Slurry Feeding of a Glass Melter
Authors: Routt Kenneth R. 
Published: March 2011

ABSTRACTRadioactive defense waste currently stored at the Savannah River Plant in liquid form is to be immobilized by incorporation into a borosilicate glass. The glass melter for this process will consist of a refractory lined tank enclosed in a water-cooled, steel vessel and fed by an aqueous slurry of glass frit plus radioactive waste. As an aid to understanding the melting process and scaling data from small melters, conservation principles were used to develop equations for predicting the melt rate for a feedpile of arbitrary radius plus additional information regarding feedpile behavior and energy consumption.
Efficient Particulate Scrubber for Glass Melter Off-Gas
Authors: Wright G. T. 
Published: March 2011

ABSTRACTOperation of joule-heated, continuous slurry-fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating - type venturi scrubber processing a simulated melter off-gas aerosol. Mass overall removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed.
The Canadian Container Development Program For Fuel Isolation
Authors: Nuttall K. , Crosthwaite J.L. , Mckay P. , Mathew P.M. , Teper B. , Maak P.Y.Y. , Moles M.D.C. 
Published: March 2011

ABSTRACTProgress in the Canadian program to develop durable containment systems for the direct disposal of irradiated fuel in a deep geologic vault is described. Possible containment lifetimes, and the factors that influence container design and materials selection, are discussed. Most effort is currently directed toward developing containers with a design lifetime of about 500 years, using a corrosion-resistant metal shell to provide the primary barrier to radionuclide release. The design details for various containers are described, together with the fabrication and testing programs that are in progress or planned. The container materials programs consist of both generic research, to enable predictions of container performance to be made, and engineering development, to evaluate methods of container fabrication and inspection.
Diffusion of Radionuclides in Brine-Saturated Backfill Barrier Materials
Authors: Nowak E. J. 
Published: March 2011

ABSTRACTThe diffusion of cesium(I), strontium(II), pertechnetate and europium in brine-saturated backfill materials was measured. Plastic diffusion cells containing cylindrical diffusion columns were used for low density backfill materials. The diffusion of gamma-emitters was followed by a gamma scanning technique. Metal diffusion cells constructed entirely from Hastelloy C-276 were used for the diffusion of pertechnetate in highly compacted bentonite. Apparent distribution coefficients calculated from diffusion data are (a) 0.02 m3 /kg for cesium(I) in 40 wt.% mordenite and 60 wt.% bentonite; (b) 0.04 m3/kg for strontium(II) in 10 wt.% sodium titanate and 90 wt.% bentonite; (c) 0.5 m3/kg for pertechnetate in 70 wt.% charcoal and 30 wt.% bentonite; and (d) 3 m3/kg for europium in 100% bentonite. Backfill effectiveness estimates based on batch sorption measurements were supported by these results;however, the diffusion results for europium did not agree well with a model for diffusion retarded by linear sorption. First measurements of pertechnetate diffusion in highly compacted bentonite suggest that anion exclusion may play a role in reducing mass transport rates of anions in this material. Needs for diffusion measurements that take into account site-specific materials interactions are described.
Internal Hydrogen Effects in Ti Code 12 Overpack/Cannister Material
Authors: Moody Neville , Robinson Steve 
Published: March 2011

ABSTRACTThe effects of internal hydrogen on the mechanical properties of Ti Code 12 were studied by gas phase charging smooth bar tensile samples. Tensile tests showed no change in yield strength with increasing hydrogen concentration. A slight decrease in ductility and fracture stress at hydrogen concentrations above 200 wppm accompanied by secondary cracking along grain boundaries indicated embrittlement. At hydrogen concentrations near and above 400 wppm, cleavage fracture associated with strain-induced hydrides was also observed.
The Microstructural Response of a Multilayer Thin Film to Local Laser Heating
Authors: Libera Matthew R. , Chen Martin , Rubin Kurt A. 
Published: March 2011

ABSTRACTThe microstructures associated with pulsed-laser heating of multilayer thin films used for phase-change optical data storage are studied in three related films. Two employ the multilayer structure SiOx/TeGeSn/SiOx where the chalcogenide layer is either amorphous or crystalline. The third uses the same trilayer structure with a crystalline chalcogenide layer but with an additional layer of aluminum. Pulsed-laser melting of micron-sized spots leads to solidification in the non-aluminized specimens with a morphology dependent on the preexisting structure of the chalcogenide layer and to amorphization in the aluminized film. Heat-flow modelling shows that the maximum temperature reached is lower and the cooling rate through the glass-forming temperature range higher in the aluminized structure. Discussion centers on the thermal and optical properties of the different films and the impact of the pre-existing chalcogenide structure on the subsequent phase transformations.
Chemical Effects Induced by Low-Energy Particle Beams in Fluorozirconate Glasses
Authors: Marletta Giovanni , Ferraris Monica 
Published: March 2011

ABSTRACTThe modification of the chemical structure of fluorozirconate glasses (ZBLAN) with Ar ion and atom beams of low energy (2–10 key) has been studied in comparison with the damage produced in the starting polycrystalline ZrF4 and BaF2. A variety of reduced chemical states of Zr is produced in ZrF4 as well as in ZBLAN glasses, including metallic Zr0 state. A strong enhancement of the amount of the metallic Zr formed under irradiation is observed in ZBLAN, while it is present only as trace in the irradiated pure ZrF4 samples. The reported effect is tentatively attributed to the presence of Ba ions in the glass network which could prompt the self-trapping of radiation-induced defects at the Zr sites, involving their progressive reduction
Ferroelectric Thin Films by sol-gel Processing
Authors: Swartz S. L. , Melling P. J. , Grant C. S. 
Published: March 2011

ABSTRACTThe sol-gel processing of ferroelectric thin films is being investigated at Battelle. The ferroelectric materials included in this study are PbTiO3, Pb(Zr, Ti)O3 (PZT), and KNbO3. The sol-gel processing and crystallization of these films on fused silica, silicon, alumina, and single crystal SrTiO3 substrates is described.Sol-gel derived PbTiO3 thin films crystallized into the expected tetragonal perovskite structure when heated to 500 C and above. However, the crystallization of sol-gel PZT (20/80) thin films was found to be substratedependent. The heat-treated PZT films were amorphous when deposited on silica and silicon substrates. Crystalline perovskite PZT films were produced on alumina substrates, and epitaxial PZT films were produced on single-crystal SrTiO3. Heat treatment of sol-gel KNbO3 films on silicon and alumina substrates resulted in the crystallization of a variety of non-perovskite phases, but epitaxial growth of KNbO3 was observed on single crystal SrTiO3.
Ion implanted electrooptical waveguides
Authors: Bremer T. 
Published: March 2011

ABSTRACTThe influence of ion beam induced lattice damage on the refractive indices is evaluated for He+ implanted planar waveguides in lithium niobate (LiNbO3) and potassium niobate (KNbO3 ). KNbO3 exhibits a higher sensitivity for ion beam induced refractive index alterations. In order to suppress leaky modes, varying angle implantation has been applied. The annealing of electronic damage in both crystals is compared. While it requires heating up to 200°C for LiNbO3, the electronic damage in KNbO3 has been found to anneal at much lower temperatures. Annealing takes place even at room temparature, the electronic damage vanishes almost completely within 100 days.
Ion Implantation of Ti INTO LiNbO3: Fabrication of Waveguides and Simple Modulators
Authors: White C. W. , Thomas D. K. , Ashley P. R. , Chang W. S. C. , Buchal C. 
Published: March 2011

ABSTRACTIon implantation has been used to introduce Ti at very high doses (>3 × 1017 /cm2) into the near-surface region of LiNbO3 to change the index of refraction.’ In the as-implanted state, the near surface is amorphous. Thermal annealing in water-saturated oxygen 1000°C crystallizes the amorphous region and incorporates the Ti into substitutional sites in the lattice at concentrations that exceed 10 at.%. Recrystallization takes place by solid-phase epitaxy. Both planar and channel waveguides have been fabricated with optical attenuations of <1 dB/cm. Both Mach-Zehnder and Bragg modulators have been fabricated using Ti implantation of LiNbO3. The characteristics of these devices have been determined and will be reported. The higher Ti concentrations which can be achieved by implantation allows tighter mode confinement and smaller mode profiles than with Ti-diffused guides.
Growth and Structural Characterization of Znse Single Crystals
Authors: Anderson Elmer E. , Cheng Hai- Yuin , Edgell Michael J. 
Published: March 2011

ABSTRACTSingle crystals of ZnSe have been grown by the physical vapor transport method in sealed quartz ampoules. The largest crystal grown measures 1 cm x 4 mm x 2 mm and required a total growing time of 11 days. Polished wafers cut from the crystals have been etched and examined by optical microscopy, x-ray diffraction, scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and scanning Auger microscopy (SAM). No impurities or unwanted phases were detected, but frequent twinning occurs. Zn-rich {111} faces were identified by SAM. Triangular etch pits are observed on Zn {lll} faces but not on Se faces. Etch pit densities are about 104 per cm2 on slow-cooled samples but are about 100 times greater when cooling is more rapid.
Crystal Chemistry, Synthesis, and Characterization of Infrared Optical Materials
Authors: Kipp D. O. , Lowe-Ma C. K. , Vanderah T. A. 
Published: March 2011

ABSTRACTNon-oxide inorganic compounds such as sulfides, phosphides, and mixed-anion sulfidephosphides are of interest as possible infrared window materials. Our research on the solid state chemistry and structure-property relationships of these materials includes the directed synthesis of new compounds as well as the study of compounds that have been reported in the literature but which have been incompletely characterized for this application. The present work includes investigations of three ternary sulfide systems: ZnGa2S4, AIn2S4, (A = Ca,Sr,Ba), and CaY2S4. Samples were prepared in polycrystalline form and/or as crystals. New compounds were obtained in our studies of the CaIn2S4, SrIn2S4, and CaY2S4 systems. Compounds were characterized by X-ray diffraction, elemental analysis, FMR, and thermogravimetric analysis.
Structure and Nonlinear Optical Properties of Glasses for Photonic Switching
Authors: Vogel E. M. , Krol D. M. , Jackel J. L. , Aitchison J. S. 
Published: March 2011

ABSTRACTThe possible use of glasses as the nonlinear optical material in all-optical switching calls for glasses with nonlinear refractive indices much higher than those of vitreous silica. Relatively high values of the nonlinear index coefficient, n2, have been found in Na2O-TiO2-Nb2O5-SiO2 glasses, in which n2 is completely dominated by the Ti-O and Nb-O bonds. We have investigated the nonlinear optical properties of R2O-TiO2-Nb2O5-SiO2 glasses as a function of the monovalent ion R (Na, K, Rb, Cs, TI). The results show that the dependence of n2 on R is larger than predicted from the empirical relation between n2 and n. An especially large enhancement of n2 is seen for T1. This can be explained by the difference in electronic configuration between TI (unfilled shell) and the alkali ions (filled shell).
”Automatized” Peel Testing: Calculated Stresses and Deflections in the Film
Authors: Suhir Ephraim 
Published: March 2011

AbstractFilm adhesion, which is an important reliability factor in many microelectronic structures, is usually evaluated by peel testing. The loading and the peel angle in peel tests can be controlled best if these tests are “automatized”, which could be done, for instance, by applying air pressure to a film through an opening in the substrate. We consider a rectangular opening and determine, how this pressure is related to the peel (membrane) loading and peel angle for the given film material and thickness. Our study is based on von-Kármán's equations for large deflections of plates. The obtained results provide mechanical fundamentals for a rational physical design of a peel test vehicle.
Low Temperature Route to Cordierite Ceramics Using a Reactive Liquid Phase Sintering Aid. Dense Body Preparation and Green Tape Fabrication
Authors: Dupon Ryan W. , Mcconville Richard L. , Thompson Mark S. 
Published: March 2011

AbstractBismuth oxide has been found to be a useful flux for the preparation of dense body cordierite (Mg2Al4Si5O18). The use of as little as 2 atom% bismuth ion with the appropriate mixture of commercially available oxide starting materials serves to produce fully dense crystalline cordierite after firing at 1000 °C. The microstructure of the sintered body (92 w/o% cordierite, 8 w/o% bismuth oxide) has the residual bismuth oxide flux distributed in discontinuous domains at the grain boundaries and at the triple points. Physical properties such as thermal coefficient of expansion and dielectric constant are largely unperturbed by the presence of the flux.Green tapes having high volume fraction solids loading have been fabricated from bismuth oxide-cordierite precursor powders. The subsequent firing at 1000 °C of laminated green tapes yields fully dense ceramic bodies of crystalline cordierite.
Mullite Ceramics for the Application to Advanced Packaging Technology
Authors: Tanaka Jun , Kajita Satoshi , Terasawa Masami 
Published: March 2011

AbstractMullite ceramics were developed for multilayered packages, which have a lower dielectric constant and a nearer thermal expansion to that of silicon than those of alumina. The multilayered mullite packages are manufactured by using a similar cofired technology with tungsten or molybdenum to the conventionally used alumina system. A new brazing material and a new lead material were developed to be combined with the mullite ceramics Multilayered mullite packages with a brazed aluminum nitride heat sink, which has a high thermal conductivity, were developed to compensate a low thermal conductivity of the mullite itself. The packages are one of the highest performance packages.
Ceramics in Microelectronics Packaging: Past, Present and Future
Authors: Tummala Rao R. 
Published: March 2011

AbstractA broad review of ceramics in microelectronics for processing, storing, transferring, printing, and displaying information is highlighted. Ceramic packaging is presented with a review of the history, evolution, and state of the art. The recent developments in ceramics resulting in potentially improved thermal and electrical properties by the use of SiC, AIN, and glass±ceramics are discussed. The scientific understanding necessary to support these developments is mentioned.
Straight Wall Bumps for High Lead Count Devices: Photolithography and Physical Properties.
Authors: Milosevic Ivana , Jasper Joerg 
Published: March 2011

AbstractThis paper will report on a novel photolithographic process suitable for the fabrication of gold bumps on high lead count devices. Utilizing a photosensitive polyimide, straight wall bumps are grown completely recessed within the polyimide layer to a typical height of 25 microns.The photolithographic step of the bumping process will be described. Good layer uniformity in conjunction with exposure in vacuum hard contact mode leads to practically vertical walls of the opening in the polyimide layer after develop.Straight wall gold bumps have been electroplated in 30 micron wide openings with a 50 micron centerline spacing. This density is beyond the present spacing capability of TAB in production. The bumping process is no longer the limiting factor in high lead count device fabrication.Potential residues in the polyimide openings would result in bad bump adhesion strength and high bump contact resistance to the underlying metallization. These two parameters were used for the process optimization.
Review of Critical Variables Determining Solder Fatigue Lives
Authors: Solomon Harvey D. 
Published: March 2011

AbstractThe fatigue of solder joints is a dominant factor limiting the long term reliability of electrical devices, especially when modern surface mounting is employed to attach devices to wiring boards. This paper will review the critical variables which determine the fatigue of solder and solder interconnections for the joints encountered with surface mounted devices. Consideration will first be given to the variables determining the displacement that a joint experiences due to an imposed thermal cycle. This displacement will then be related to strains in the joint. These strains are then correlated to the fatigue life. This final correlation requires not only a knowledge of the magnitude of the strain which is being applied, but also nature of the joint geometry, type of solder employed, stress state, the definition of failure, the frequency of fatigue cycling, the introduction of hold times, the environment (both thermal and gaseous) and the occurrence of metallurgical changes. The importance of these critical variables will be discussed along with an outline of design approaches to predict the fatigue life. Data for tests on eutectic Pb-Sn solder and for a Pb rich solder will be presented and used to illustrate the influence of critical variables on the fatigue life and to illustrate design approaches.
Metallization Issues in Advanced Ceramic Substrates:- Microstructural. Microchemistry and Thermal Conductivity in Aln
Authors: Westwood Alistair D. , Notis Michael R. 
Published: March 2011

AbstractMicrochemical and microstructural study has been carried out on the tungsten-aluminum nitride (W-AlN) thick film metallization interface. A reaction has been found to occur with the formation of precipitates at AlN grain boundaries and also within the AlN grains; a thin crystalline grain boundary film was also observed. The interface morphology and chemistry is compared to the molybdenum/manganese-aluminum nitride (MoMn-AlN) interface. The effects of morphology and microchemical variations upon thermal conductivity are discussed.
The Formation of Molecular Composites by a Modified Solgel Process
Authors: Lessard Ronald B. , Wallacet Mary M. , Oertling W. Anthony , Chang Chi K. , Berglund Kris A. , Nocera Daniel G. 
Published: March 2011

ABSTRACTStandard sol-gel procedures have been modified to permit sol-gel synthesis to be performed at varying hydrogen ion concentrations and in a variety of organic solvents. These modifications greatly expand the variety of guest molecules that can be incorporated into nondense glassy environments. Processing conditions can be controlled such that the guest compounds generally retain their solution properties thereby allowing new molecular composites to be formed. Reported herein is the incorporation of both porphyrins and metalloporphyrins into silica matrices. Electronic absorption, vibrational, and excited state luminescence properties of the resulting composites clearly demonstrate that the molecular and electronic structure of the porphyrins and metalloporphyrins are preserved during sol-gel processing and in the ceramic matrices. This retention of properties has been shown for guest molecules doped into monoliths as well as films.