bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-Invasive Determination of Waste Drum Pressurization by Acoustic Resonance Spectroscopy
Authors: Sinha Dipen N. , Kosiewicz Stanley T. 
Published: March 2011

ABSTRACTPreliminary work suggests that Acoustic Resonance Spectroscopy (ARS) can non-invasively determine gas pressurization of waste drums. This is done by exciting the various mechanical vibrational modes of the test drum and analyzing the characteristics of the resulting resonance frequencies and their higher harmonics. If the contained waste is a liquid, the liquid level and also some properties of the liquid including density can be determined. Additional work is needed to exploit this novel acoustic technique for noninvasive characterization of waste storage drums.
Basic Radiation Damage Processes in Ionic Solids: The Role of Collisional Electron Capture
Authors: Fine J. , Szymonski M. , Kolodziej J. , Yoshitake M. , Franzreb K. 
Published: March 2011

ABSTRACTA new class of inelastic collisional processes accounts for the electron spectra of ion-bombarded sodium halide surfaces. These spectra indicate that the deexcitation process consists of a sequence of lattice-ion collisions in which localized electron transfer occurs. Such collisional processes demonstrate how collisions can initiate electronic change in molecular compounds and that electron-transfer processes must play an essential role in chemistry activated by energetic collisions.
Cement Minerals at Elevated Temperature: Thermodynamic and Structural Characteristics
Authors: Bruton Carol J. , Phillips Brian L. , Meike Annemarie , Martin Sue , Viani Brian E. 
Published: March 2011

ABSTRACTAn experimental and modeling program has been designed to elucidate the structural and thermodynamic response of cement minerals to elevated temperature. The components of the program include: a) synthesis of hydrated Ca-silicates; b) structural analysis of cement phases during heating and dehydration/rehydration; c) mechanistic and thermodynamic descriptions of the hydration/dehydration behavior of hydrated Ca-silicates as a function of temperature, pressure and relative humidity; d) study of naturally occurring hydrated Ca-silicates; and e) measurements of thermodynamic data for hydrated Ca-silicates.
Retention Capability of Cement Barriers Applied in Nuclear Field
Authors: Ghattas N.K. , Ghorab H.Y. , Eskander S.B. , Bayoumi T.A. 
Published: March 2011

ABSTRACTThe fraction released of radioactive cesium from waste forms (obtained by incorporating a given amount of simulated labelled waste materials into cement) was greater than that released when introducing the same amount of waste into a preformed cement container. Moreover, improving cement containers using chemical treatment or additives (organic or inorganic) lowers the fraction released. The effect of waste materials on cement hydration and on the properties of the obtained products has been studied. To improve repository performance it is therefore preferable to ameliorate the confinement properties of preformed cement containers rather than radioactive waste forms. In improving waste forms we are dealing with a complicated system resulting from the interaction of waste materials with cement besides allowing extra doses to workers and finally increasing the final total coasts.
Nuclear Waste Analytical Round Robins 1-6 Summary Report
Authors: Smith Gary L. , Marschman Steven C. 
Published: March 2011

ABSTRACTThe Materials Characterization Center (MCC) at Pacific Northwest Laboratory(a) conducts Nuclear Waste Analytical Round Robins on simulated waste glasses with and without radionuclides. The analytical round robins are used to provide analytical laboratories with a forum for improving the accuracy and precision of analytical techniques that will be used for characterizing nuclear waste glasses. Chemical analysis data on glass waste forms produced by the nuclear waste community may need to withstand legal challenges for waste material storage qualification and for licensing repositories. Determining the quality of analytical data is important for meeting these challenges, making process operation decisions, and predicting long-term waste behavior.The MCC has conducted six round robins for the waste management, research, and development community from 1987 to the present time. The laboratories that have participated regularly are Ames, Argonne, Catholic University, Lawrence Livermore, Pacific Northwest Laboratory, Savannah River, and West Valley Nuclear. The glass types analyzed in these round robins all have been simulated nuclear waste compositions expected from the vitrification of high-level nuclear waste. A wide range of analytical procedures have been used by the participating laboratories, including Atomic Absorption spectroscopy, inductively coupled plasma-atomic emission spectro-scopy, direct current plasma-emission spectroscopy, and inductively coupled plasma-mass spectroscopy techniques. The consensus average relative error for Round Robins 1 through 6 is 5.4%, with values ranging from 9.4 to 1.1%. The trend on the average improved with each round robin. When the laboratories analyzed samples over longer periods of time, the intralaboratory variability increased. Lab-to-lab variation accounts for most of the total variability found in all the round robins. To date, participation in the radiochemistry portion has been minimal and the analytical results poor when compared to the nonradiochemistry portion of the round robins. Additional radiochemical work is needed in future round robins.
Dissolution Mechanism of Soda-Lime Silicate Glass and of PNL 76-68 in the Presence of Dissolved Mg
Authors: Sang Jing C. , Guo Yan , Barkatt Alisa , Adel-Hadadi M.A. , Marbury Gwendolyn S. , Barkatt Aaron 
Published: March 2011

ABSTRACTLeaching studies were performed on powdered PNL 76-68 glass in de-ionized water in the presence of Mg solute. The results showed that the presence of Mg in the leachant greatly reduced the rate of glass dissolution. The equation Q=krα was used to express the experimental data. In the absence of Mg, α was about 1, i.e., the amount of glass dissolved was linear with time. In the presence of Mg, α was close to 0.5, i.e. the extracted amount was proportional to the square root of time. Therefore, the reduction of the dissolution rate of PNL 76-68 glass in the presence of Mg solute could be explained as a result of a change in the glass dissolution mechanism.Comparative leaching studies on bulk soda-lime silicate glass in a sodium borate buffered system (pH 8.1) showed the same results. The presence of Mg in the leachant reduced the rate of glass dissolution. In the absence of Mg, α was about 1, while in the presence of Mg, α was 0.5. This change in α was not caused by changes in pH, and it represents a real change in the glass dissolution mechanism.
The Inpluence of Borehole Flushing on the Concentration of Microbes in Granitic Groundwaters.
Authors: Stroes-Gascoyne S. , Gascoyne M. , Hamon C.J. , Jain D. , Vilks P. 
Published: March 2011

ABSTRACTA number of groundvater parameters have been studied at AECL’s Underground Research Laboratory (URL) in support of the Canadian Nuclear Fuel Waste Management Program. The concentration of microbes in groundvater is of interest as they may modify the transport of dissolved radionuclides. Preliminary results from an earlier study suggested that the microbe concentrations may be affected by the extent of borehole flushing prior to sampling. A study was therefore carried out in which packer-isolated intervals of two boreholes intersecting a fracture zone at 250-m depth in the URL were flushed and sampled on two occasions at various flow rates. High initial microbial concentrations (most likely due to leaching of nutrients from sample tubes) decreased rapidly as flushing progressed, suggesting enhanced microbial growth near the top of the borehole zone. Also, a tenfold increase in flow rate during flushing caused an increase in microbial concentrations in the groundwater of one of the boreholes, concurrent with an increase in total particle count. This suggests that particulate and biofilm material may be flushed out of the fracture zone at this particular location.
Determination of the Composition and Thickness of Thin Potassium Polyphosphide Films
Authors: Kiss Klara , Figura Paul M. 
Published: March 2011

An energy dispersive X-ray microprobe (EDX) analysis was developed to determine simultaneously the lateral uniformity of the thickness and the composition of thin potassium polyphosphide(KPx) films. The EDX analysis was based on theoretical calibration curves generated by the Monte Carlo simulation approach developed by Kyser and Murata and extended by Miller and Koffman. Simultaneous determination of both composition and thickness was possible for this binary-element thin film due to the concentration independence of the theoretical intensity ratio ofThe EDX results were compared to macro techniques applied routinely in the characterization of thin films, i.e., piezoelectric thickness measurement and compositional analysis via X-ray fluorescence spectroscopy (XRF). A special XRF technique was developed to determine the weight ratios from fluorescent intensity measurements “directly” using “bulk” standards instead of thin film standards. The accuracy of this technique was demonstrated for an indium phosphide standard film since no certified KPx standard films are available.The comparison was carried out on films of widely different thicknesses (0.26–2.0 um) and compositions (KP5–KP83). A Student's t test demonstrated that the compared techniques were identical at the 95% confidence level for the determinations of both thickness and composition. Thus, EDX analysis can be used to complement the macro techniques when the lateral uniformity of the thin films is to be determined at the micron scale.
Electron Energy Loss Fine Structure of Carbides and Nitrides
Authors: Disko Mark M. 
Published: March 2011

ABSTRACTTransition metal carbides and nitrides are important in a wide range of materials problems which include precipitates in high strength alloys and ceramic wear coatings. Electron energy loss spectroscopy (EELS) is a high spatial resolution (probe sizes < 100nm) analytical technique which is sensitive to variations in carbon or nitrogen stoichiometry. This sensitivity to light elements depends on the ability to relate the measured EELS spectrum to a material's electronic structure. The unique capabilities of EELS for the characterization of carbonitrides with high spatial resolution are discussed along with some of the experimental and analytical methods used to relate measured spectra to electronic structure. Data are presented for several members of the systems Ti-N-C and Cr-Fe-C.
Quality and Reliability Assurance of Semiconductor Devices through Transmission Electron Microscopy
Authors: Pinizzotto R. F. , Clark F. Y. , Jarvis M. L. 
Published: March 2011

ABSTRACTModern methods of sample preparation have made it possible to analyze complete, packaged integrated circuits by transmission electron microscopy. TEM has two unique capabilities that cannot be matched by other characterization methods: 1) it is a direct crystallographic probe and 2) it has excellent spatial resolution, 0.2 nm. Small personal computers can be used to translate the micrographic data into statistical information that can be analyzed by non-TEM trained engineers. The data can also be stored in a MICROSTRUCTURAL DATABANK. The experimental data is automatically compared by the computer with previously established criteria. This methodology generates additional information that is used for quality and reliability assurance testing of integrated circuits. The method is applicable to devices that are removed from electronic systems after field operation, as well as to devices that have been lifetime tested. Two examples are described and discussed: aluminum grain size distribution analysis and silicide layer thickness measurement.
Compositional Profiling of Rapidly Solidified Cellular Structures
Authors: Mackey Terrence M. , Kelly Thomas F. 
Published: March 2011

ABSTRACTSolute partitioning during rapid solidification is being studied in cellular growth structures produced via pulsed-laser melting of binary alloys. This rapid solidification process can generate significant departures from local equilibrium at the liquid-solid interface which directly affects the resultant microsegregation patterns. Calculated compositional profiles are obtained from a solidification model incorporating the effects of both solute trapping and solute buildup with a suitable tip stability criterion. These are compared to experimentally determined campositional profiles generated across the steady-state cellular regrowth region of the melt pool using STEM x-ray microanalysis.
Center for Nondestructive Evaluation
Authors: Green Robert E. 
Published: March 2011

ABSTRACTThe Johns Hopkins University Center for Nondestructive Evaluation (CNDE) has recently been established as an interdisciplinary center for research and instruction which draws on the resources and talent of the School of Engineering, the Applied Physics Laboratory, and the School of Medicine. The nondestructive evaluation techniques developed and employed are especially useful to control and improve product quality in manufacturing processes and to assure the highest level of reliability for materials, parts, and products. The center is dedicated to research which will lead to more sophisticated and accurate methods for the nondestructive evaluation of materials and systems and to the education of talented students who will enter the NDE field. The CNDE is a cooperative venture between the University, Industrial Affiliates, and Government Agencies. The present paper will describe the CNDE and the current and planned educational program in materials education.
Measurement of Particle Densities and Sizes: Application to Silane/Argon Plasmas
Authors: Spears Kenneth G. , Robinson Timothy J. 
Published: March 2011

AbstractWe discuss new methods for measuring particle number densities, masses and size distributions by laser techniques.These methods do not require assumptions of particle optical properties or instrumental calibration by known particles.We summarize the theoretical basis of these techniques and discuss the light scattering fluctuation analysis, which can yield number density and size information.Experimental data for rf discharges of silane/argon mixtures are briefly presented to illustrate some of the theoretical predictions.
Kinetic Modeling and Measurement of Active Species Distributions During Dry Etching
Authors: Uhm K. S. , Kump M. R. , Mcvittie J. P. , Dutton R. W. 
Published: March 2011

AbstractA simple kinetic dry etching model accounting for generation, loss, and transport of the reactive and by-product species is developed.To demonstrate and evaluate the model, the etching of silicon using SF6+O2+Ar in the plasma etch mode is investigated.
In Situ Etching Rate Measurement of Si with XeF2
Authors: Padmanabhan K. R. , Bhowmick S. , Shaver R. , Hua Zhang Zu , Buchholz J. C. 
Published: March 2011

AbstractIon backscattering and channeling techniques have been employed to measure the etching rate of amorphous and single crystal Si by XeF2 under similar conditions.Both (100) Si on sapphire and (111) Si on spinel showed higher etching rates compared to amorphous Si.However, measurements of the etching rate using a Si cell aligned to the axis and along the planes under similar conditions did not show appreciable difference in the etching rate compared to the etching rate with random orientation of the cell.Presence of the analyzing 4He+ beam during etching enhances the etching rate to twice the value when compared to post etching analysis with the same beam.The enhancement of the etching rate due to ion induced decomposition of XeF2 have been considered in the explanation of the experimental results.
Performance Optimization of Woven Fabric Composites for Printed Circuit Boards
Authors: Chou Tsu-Wei , Yang Jenn-Ming 
Published: March 2011

AbstractWoven fabric composites have been used extensively as substrate materials for multilayer printed circuit boards. This paper presents a brief overview of the recent accomplishments in the modeling and characterization of woven fabric composites. Three analytical models have been developed to predict the thermo-mechanical properties of fabric composites with various weaving geometries. A three-dimensional finite element analysis has also been adopted to determine the properties of plain-weave fabric composites.Parametric studies are performed for both hybrid and non-hybrid woven fabric composites to generate data for materials selection and design. These data are presented in the form of “structure-performance maps” where the unique characteristics and relative effectiveness of various woven fabric composites can be easily assessed. The potential of tailoring a low thermal expansion coefficient substrate material through suitable materials selection, geometrical design, and fiber hybridization is also discussed.
Interdiffusion in Polyimide Thin Films
Authors: Kramer E. J. , Volksen W. , Russell T. P. 
Published: March 2011

AbstractThe interdiffusion in thin films of polyimide has been investigated using the forward recoil spectrometry (FRES) technique. Films 5–10 μm in thickness of polyamic acid spin coated onto a silicon substrate were imidized at a temperature TI. A second film, ∼300Å in thickness of perdeuterated polyamic acid was spin-coated onto the first layer and heated to a temperature TD to allow interdiffusion of the two films and imidization of the second coating. Depth profiling of the deuterated polymer by FRES showed that no interdiffusion occurred if TI>TD and TI>200°C. Substantial interdiffusion occurred if TD>TI and TI<400° C. Time averaged tracer diffusion coefficients were found to vary with the TD and TI, as well as the length of time allowed for interdiffusion. Since conversion of the deuterated polyamic acid to polyimide occurs at the diffusion temperature, the results are consistent with a relatively large diffusion coefficient for the polyamic acid (D>2.5× 10−14 cm2/sec) which decreases to a negligible value as the molecule is fully converted to the corresponding polyimide.
Stem Observations of the Microstructures Present in Polymer Blend Thin Films.
Authors: Sickafus K. E. , Berger S. D. , Donald A. M. 
Published: March 2011

AbstractThis paper examines the effectiveness of scanning transmission electron microscopy (STEM) as an analytical tool for determining composition in multi-phase polymer blend microstructures. The polymer blend polystyrene (PS) - polyether sulphone (PES) thin film used in this study exhibited a two-phase microstructure consisting of PES-rich inclusions, ranging from 0.2μm to 1.2μm in diameter, in a PS-rich matrix. Emphasis in this presentation is placed on the use of annular dark-field (ADF) STEM image contrast to infer information concerning the local composition of adjacent microstructural features.
Impact of Isotope Effects on the SANS Analysis of Amorphous Polymers
Authors: Bates F. S. , Koehler W. C. , Wignall G. D. , Fetters L. J. 
Published: March 2011

AbstractBinary mixtures of the perdeuterated and protonated isotopes of four amorphous polymerspolystyrenes, 1,4-polybutadienes, 1,2-polybutadienes, and 1,2-polybutenes – have been examined by small-angle neutron scattering (SANS). In each case, evaluation of the SANS results based on the RPA theory of de Gennes indicates non-ideal mixing characterized by a Flory-Huggins interaction parameter 10-4 < χ 10-3. All four χ parameters can be closely predicted based on the measured change in the carbon-hydrogen bond polarizability with deuterium substitution. These findings are discussed in the context of past SANS studies of amorphous polymers.
A Reduced Variable Approach to Relating Creep and Creep Rupture in PMMA
Authors: McKenna G. B. , Crissman J. M. 
Published: March 2011

AbstractCreep and creep rupture of PMMA at high stresses have been characterized and found to be relatable by use of reduced variables, it is shown that when the creep compliances can be correlated by a superposition principle for which the vertical shift is the ratio of the applied stress to a reference stress and when strain at failure is a constant, a commonly used failure criterion (that the product of the strain rate at failure and the time to failure is constant) becomes valid. The reduced variables approach is found to apply to two greatly different thermal histories. Consistent with the concept of physical aging, the response of a quenched sample is simply shifted along the log time axis to shorter times relative to the response of the aged sample.
Viscoelastic Relaxation in Glassy Polymers
Authors: Chow T. S. 
Published: March 2011

AbstractThe nonequilibrium mechanism controlling the viscoelastic response in the glassy state is analyzed in accordance with our multiple hole energy model. The change in the nonequilibrium glassy state defines the Struik physical aging exponent and determines the motion of the relaxation time spectrum, the transition of the global shift factor and the slow decay of the stress relaxation modulus especially at longer times in the glassy state where the Kohlrausch-Williams-Watts function fails. Although the distribution of relaxation times has its time scales shifted with the aging time, the shape of the spectrum remains very much the same which supports the notion of thermo-aging-rheological simplicity in the glassy and transition states.
Deformation Induced Dilatations and New Observations on Fracture In Compression in Metallic Glasses at Low Temperatures
Authors: Megusar Janez , Argon Ali S. , Grant Nicholas J. 
Published: March 2011

ABSTRACTDeformation induced dilatations were measured on a Pd-Cu-Si glass by a differential dilatometric method during crystallization. At large pre-strains, these dilatations are large and of the order of 20%. Fracture surfaces of specimens in compression show either the characteristic features of tensile separation or evidence for repeated nucleation of fracture. Rubbing was observed only in a small fraction of a fracture surface.
Rapidly Solidified Long Range Ordered Alloys
Authors: Lee E. H. , Koch C. C. , Liu C. T. 
Published: March 2011

ABSTRACTThe influence of rapid solidification processing on the microstructure of long-range-ordered alloys in the (Fe,Co,Ni)3 V system has been studied by transmission electron microscopy. The main microstructural feature of the asquenched alloys was a fine cell structure (∼300 nm diameter) decorated with carbide particles. This structure was maintained after annealing treatments which develop the ordered crystal structure. Other features of the microstructures both before and after annealing are presented and discussed.
Critical Factors in Laser and Electron Beam Glazing of Materials.
Authors: Strutt P. R. , Lewis B. G. , Kear B. H. 
Published: March 2011

ABSTRACTThe major effects of laser and electron beam glazing on solidification microstructure and melt zone geometry are described. It is shown that under comparable processing conditions, i.e. absorbed power density and interaction time, the glazed microstructures are similar. Some variations in microstructure of laser and electron beam glazed M2 steel have been noted, which seem to be related to fluid flow effects in the melt zone and possible interactions with the environment.