Resource Type

Preparation of multilayered materials in cross-section for in situ TEM tensile deformation studies (open access)

Preparation of multilayered materials in cross-section for in situ TEM tensile deformation studies

The success of in-situ transmission electron microscopy experimentation is often dictated by proper specimen preparation. We report here a novel technique permitting the production of cross-sectioned tensile specimens of multilayered films for in-situ deformation studies. Of primary importance in the development of this technique is the production of an electron transparent micro-gauge section using focused ion beam technology. This microgauge section predetermines the position at which plastic deformation is initiated; crack nucleation, growth and failure are then subsequently observed.
Date: May 13, 1997
Creator: Wall, M. A.
System: The UNT Digital Library
A study of turbulence in an evolving stable atmospheric boundary layer using large-eddy simulation (open access)

A study of turbulence in an evolving stable atmospheric boundary layer using large-eddy simulation

A study is made of the effects of stable stratification on the fine-scale features of the flow in an evolving stable boundary layer (SBL). Large-eddy simulation (LES) techniques are used so that spatially and temporally varying and intermittent features of the turbulence can be resolved; traditional Reynolds-averaging approaches are not well suited to this. The LES model employs a subgrid turbulence model that allows upscale energy transfer (backscatter) and incorporates the effects of buoyancy. The afternoon, evening transition, and nighttime periods are simulated. Highly anisotropic turbulence is found in the developed SBL, with occasional periods of enhanced turbulence. Energy backscatter occurs in a fashion similar to that found in DNS, and is an important capability in LES of the SBL. Coherent structures are dominant in the SBL, as the damping of turbulent energy occurs more at the smaller, less organized scales.
Date: May 1, 1999
Creator: Cederwall, R & Street, R L
System: The UNT Digital Library
Direct flow in 10.8 GeV/nucleon Au+Au collisions measured in experiment E917 at the AGS. (open access)

Direct flow in 10.8 GeV/nucleon Au+Au collisions measured in experiment E917 at the AGS.

Analysis of directed flow observable for protons and pions from Au+Au collisions at 10.8 GeV/nucleon from experiment E917 at the AGS is presented. Using a Fourier series expansion, the first Fourier component, {nu}{sub 1},was extracted as a function of rapidity for mid-central collisions (17-24%). Clear evidence for positive directed flow is found in the proton data, and a weak, possibly negative directed flow signal is observed for {pi}{sup +} and {pi}{sup {minus}}.
Date: May 19, 1999
Creator: Back, B. B.; Betts, R. R.; Britt, H. C.; Chang, J.; Chang, W. C.; Gillitzer, A. et al.
System: The UNT Digital Library
The beam envelope equation -- Systematic solution for a FODO lattice with space charge (open access)

The beam envelope equation -- Systematic solution for a FODO lattice with space charge

Many approximate solutions for matched beam envelope functions with space charge have been developed; they generally have efforts of 2--10% for the parameters of interest and cannot be reliably improved. The new, systematic approach described here provides the K-V envelope functions to arbitrarily high accuracy as a power series in the quadrupole gradient. A useful simplification results from defining the sum and difference of the envelope radii; S = (a+b)/2 varies only slightly with distance z along the system axis, and D = (a-b)/2 contains most of the envelope oscillations. To solve the coupled equations for S and D, the quadrupole strength K(z) is turned on by replacing K with {alpha}K{sub 1} and letting {alpha} increase continuously from 0 to 1. It is found that S and D may be expanded in even and odd powers of {alpha}, respectively. Equations for the coefficients of powers of {alpha} are then solved successively by integration in z. The periodicity conditions and tune integration close the calculation. Simple low order results are typically accurate to 1% or better.
Date: May 1, 1995
Creator: Lee, Edward P.
System: The UNT Digital Library
Completion of the INEEL's WERF Incinerator Trial Burn (open access)

Completion of the INEEL's WERF Incinerator Trial Burn

This paper describes the successes and challenges associated with Resource Conservation and Recovery Act (RCRA) permitting of the Idaho National Engineering and Environmental Laboratory's (INEEL) Waste Experimental Reduction Facility (WERF) hazardous and mixed waste incinerator. Topics to be discussed include facility modifications and problems, trial burn results and lessons learned in each of these areas. In addition, a number of challenges remain including completion and final issue of the RCRA Permit and implementation of all the permit requirements. Results from the trial burn demonstrated that the operating conditions and procedures will result in emissions that are satisfactorily protective of human health, the environment, and are in compliance with Federal and State regulations.
Date: May 1, 1999
Creator: Branter, C. K.; Conley, D. A.; Moser, D. R. & Corrigan, S. J.
System: The UNT Digital Library
Progress in metal ion separation and preconcentration : an overview. (open access)

Progress in metal ion separation and preconcentration : an overview.

A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented.
Date: May 19, 1998
Creator: Bond, A. H.
System: The UNT Digital Library
Plutonium and surrogate fission products in a composite ceramic waste form. (open access)

Plutonium and surrogate fission products in a composite ceramic waste form.

Argonne National Laboratory is developing a ceramic waste form to immobilize salt containing fission products and transuranic elements. Preliminary results have been presented for ceramic waste forms containing surrogate fission products such as cesium and the lanthanides. In this work results from scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction are presented in greater detail for ceramic waste forms containing surrogate fission products. Additionally, results for waste forms containing plutonium and surrogate fission products are presented. Most of the surrogate fission products appear to be silicates or aluminosilicates whereas the plutonium is usually found in an oxide form. There is also evidence for the presence of plutonium within the sodalite phase although the chemical speciation of the plutonium is not known.
Date: May 19, 1999
Creator: Esh, D. W.; Frank, S. M.; Goff, K. M.; Johnson, S. G.; Moschetti, T. L. & O'Holleran, T.
System: The UNT Digital Library
Geophysical borehole logging in the unsaturated zone, Yucca Mountain, Nevada (open access)

Geophysical borehole logging in the unsaturated zone, Yucca Mountain, Nevada

Borehole geophysical logging for site characterization in the volcanic rocks at the proposed nuclear waste repository at Yucca Mountain, Nevada, requires data collection under rather unusual conditions. Logging tools must operate in rugose, dry holes above the water table in the unsaturated zone. Not all logging tools will operate in this environment, therefore; careful consideration must be given to selection and calibration. A sample suite of logs is presented that demonstrates correlation of geological formations from borehole to borehole, the definition of zones of altered mineralogy, and the quantitative estimates of rock properties. We show the results of an exploratory calculation of porosity and water saturation based upon density and epithermal neutron logs. Comparison of the results with a few core samples is encouraging, particularly because the logs can provide continuous data in boreholes where core samples are not available. 9 refs., 4 figs.
Date: May 1, 1991
Creator: Schimschal, U. & Nelson, P.H.
System: The UNT Digital Library
Gamma-ray array physics. (open access)

Gamma-ray array physics.

In this contribution I am going to discuss the development of large arrays of Compton Suppressed, High Purity Germanium (HpGe) detectors and the physics that has been, that is being, and that will be done with them. These arrays and their science have dominated low-energy nuclear structure research for the last twenty years and will continue to do so in the foreseeable future. John Sharpey Schafer played a visionary role in convincing a skeptical world that the development of these arrays would lead to a path of enlightenment. The extent to which he succeeded can be seen both through the world-wide propagation of ever more sophisticated devices, and through the world-wide propagation of his students. I, personally, would not be working in research if it were not for Johns inspirational leadership. I am eternally grateful to him. Many excellent reviews of array physics have been made in the past which can provide detailed background reading. The review by Paul Nolan, another ex-Sharpey Schafer student, is particularly comprehensive and clear.
Date: May 25, 1999
Creator: Lister, C. J.
System: The UNT Digital Library
Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti. (open access)

Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti.

Microstructural examination results are reported for two heats of V-(4-5%) Cr-(4-5%)Ti irradiated in the EBR-II X530 experiment to 4.5 dpa at {approximately}400 C to provide an understanding of the microstructural evolution that may be associated with degradation of mechanical properties. Fine precipitates were observed in high density intermixed with small defect clusters for all conditions examined following the irradiation. The irradiation-induced precipitation does not appear to be affected by preirradiation heat treatment at 950-1125 C. There was no evidence for a significant density of large (diameter >10 nm) dislocation loops or network dislocations. Analytical investigations successfully demonstrated that the precipitates were enriched in titanium, depleted in vanadium and contained no nitrogen. These results are discussed in terms of future alloy development options.
Date: May 4, 1998
Creator: Gelles, D. S.
System: The UNT Digital Library
Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions. (open access)

Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions.

Certain radionuclide ions (e.g., TcO{sub 4}{sup 16}) exhibit unusually strong Affinities toward the polymer-rich phase in aqueous biphase systems generated by combinations of salt solutions with polymers such as poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Thus, aqueous polymer phases could potentially be used to selectively extract these ions during pretreatment of radioactive tank wastes at Hanford. To help develop a fundamental understanding of the interactions between various ions and polymers in aqueous solution, interaction enthalpies between sodium perrhenate and a random copolymer of PEG and PPG (UCON-50) were measured by microcalorimetric titration. An entropy compensation effect was observed in this system in which changes in enthalpic interactions were balanced by entropy changes such that the interaction free energy remained constant and approximately equal to zero.
Date: May 3, 1999
Creator: Chaiko, D. J.; Hatton, T. A. & Zaslavsky, B.
System: The UNT Digital Library
Scale up issues involved with the ceramic waste form : ceramic-container interactions and ceramic cracking quantification. (open access)

Scale up issues involved with the ceramic waste form : ceramic-container interactions and ceramic cracking quantification.

Argonne National Laboratory is developing a process for the conditioning of spent nuclear fuel to prepare the material for final disposal. Two waste streams will result from the treatment process, a stainless steel based form and a ceramic based form. The ceramic waste form will be enclosed in a stainless steel container. In order to assess the performance of the ceramic waste form in a repository two factors must be examined, the surface area increases caused by waste form cracking and any ceramic/canister interactions that may release toxic material. The results indicate that the surface area increases are less than the High Level Waste glass and any toxic releases are below regulatory limits.
Date: May 3, 1999
Creator: Bateman, K. J.; DiSanto, T.; Goff, K. M.; Johnson, S. G.; O'Holleran, T. & Riley, W. P., Jr.
System: The UNT Digital Library
Portable electro-mechanically cooled high-resolution germanium detector (open access)

Portable electro-mechanically cooled high-resolution germanium detector

We have integrated a small, highly-reliable, electro-mechanical cryo-cooler with a high-resolution germanium detector for portable/field applications. The system weighs 6.8 kg and requires 40 watts of power to operate once the detector is cooled to its operating temperature. the detector is a 500 mm{sup 2} by 20-mm thick low-energy configuration that gives a full-width at half maximum (FWHM) energy resolution of 523 eV at 122 keV, when cooled with liquid nitrogen. The energy resolution of the detector, when cooled with the electro-mechanical cooler, is 570 eV at 122 keV. We have field tested this system in measurements of plutonium and uranium for isotopic and enrichment information using the MGA and MGAU analysis programs without any noticeable effects on the results.
Date: May 1, 1995
Creator: Neufeld, K. W. & Ruhter, W. D.
System: The UNT Digital Library
Review of W and Z production at the Tevatron (open access)

Review of W and Z production at the Tevatron

The CDF and D0 collaborations have used recent data taken at the Tevatron to perform QCD tests with W and Z bosons decaying leptonically. D0 measures the production cross section times branching ratio for W and Z bosons. This also gives an indirect measurement of the total width of the W boson: {Lambda}{sub W} = 2.126 {+-} 0.092 GeV. CDF reports on a direct measurement of {Lambda}{sub W} = 2.19 {+-} 0.19 GeV, in good agreement with the indirect determination and Standard Model predictions. D0's measurement of the differential d{sigma}/dp{sub T} distribution for W and Z bosons decaying to electrons agrees with the combined QCD perturbative and resummation calculations. In addition, the d{sigma}/dp{sub T} distribution for the Z boson discriminates between different vector boson production models. Studies of W + Jet production at CDF find the NLO QCD prediction for the production rate of W + {ge} 1 Jet events to be in good agreement with the data.
Date: May 1, 1998
Creator: Gerber, Cecilia E.
System: The UNT Digital Library
Heat transfer augmentation in channels with porous copper inserts. (open access)

Heat transfer augmentation in channels with porous copper inserts.

None
Date: May 19, 1998
Creator: Kuzay, T. M.
System: The UNT Digital Library
Utilization of photoconductive gain in a-Si:H devices for radiation detection (open access)

Utilization of photoconductive gain in a-Si:H devices for radiation detection

The photoconductive gain mechanism in a-Si:H was investigated in connection with applications to radiation detection. Various device types such as p-i-n, n-i-n and n-i-p-i-n structures were fabricated and tested. Photoconductive gain was measured in two time scales: one for short pulses of visible light (<1 {mu}sec) which simulates the transit of an energetic charged particle, and the other for rather long pulses of light (1 msec) which simulates x-ray exposure in medical imaging. We used two definitions of photoconductive gain: current gain and charge gain which is an integration of the current gain. We found typical charge gains of 3 {approximately} 9 for short pulses and a few hundred for long pulses at a dark current level of 10 mA/cm{sup 2}. Various gain results are discussed in terms of the device structure, applied bias and dark current.
Date: May 1, 1995
Creator: Lee, H. K.; Drewery, J. S.; Hong, W. S.; Jing, T.; Kaplan, S. N. & Perez-Mendez, V.
System: The UNT Digital Library
Organization and management of the plant safety evaluation of the VVER-440/230 units at Novovoronezh. (open access)

Organization and management of the plant safety evaluation of the VVER-440/230 units at Novovoronezh.

As part of the Soviet-Designed Reactor Safety (SDRS) element of the International Nuclear Safety Program (INSP), the US Department of Energy (US DOE) is funding a plant safety evaluation (PSE) project for the Novovoronezh Nuclear Power Plant (NvNPP). The Novovoronezh PSE Project is a multi-faceted project with participants from sixteen different international organizations from five different countries scattered across eleven time zones. The purpose of this project is to provide a thorough Probabilistic Risk Analysis (PRA) and Deterministic Safety Analysis (DSA) for Units 3 and 4 of the NvNPP. In addition, this project provides assistance to the operation organizations in meeting their international commitments in support of safety upgrades, and their regulatory requirements for the conduct of safety analyses. Managing this project is a complex process requiring numerous management tools, constant monitoring, and effective communication skills. Employing management tools to resolve unanticipated problems one of the keys to project success. The overall scope, programmatic context, objectives, project interactions, communications, practical hindrances, and lessons learned from the challenging performance of the PSE project are summarized in this paper.
Date: May 13, 1999
Creator: Afshar, C. M.; Pizzica, P.; Puglia, W. J. & Rozin, V.
System: The UNT Digital Library
Language interoperability for high-performance parallel scientific components (open access)

Language interoperability for high-performance parallel scientific components

With the increasing complexity and interdisciplinary nature of scientific applications, code reuse is becoming increasingly important in scientific computing. One method for facilitating code reuse is the use of components technologies, which have been used widely in industry. However, components have only recently worked their way into scientific computing. Language interoperability is an important underlying technology for these component architectures. In this paper, we present an approach to language interoperability for a high-performance parallel, component architecture being developed by the Common Component Architecture (CCA) group. Our approach is based on Interface Definition Language (IDL) techniques. We have developed a Scientific Interface Definition Language (SIDL), as well as bindings to C and Fortran. We have also developed a SIDL compiler and run-time library support for reference counting, reflection, object management, and exception handling (Babel). Results from using Babel to call a standard numerical solver library (written in C) from C and Fortran show that the cost of using Babel is minimal, where as the savings in development time and the benefits of object-oriented development support for C and Fortran far outweigh the costs.
Date: May 18, 1999
Creator: Elliot, N; Kohn, S & Smolinski, B
System: The UNT Digital Library
Inverse modeling as a step in the calibration of the LBL-USGS site-scale model of Yucca Mountain (open access)

Inverse modeling as a step in the calibration of the LBL-USGS site-scale model of Yucca Mountain

Calibration of the LBL-USGS site-scale model of Yucca Mountain is initiated. Inverse modeling techniques are used to match the results of simplified submodels to the observed pressure, saturation, and temperature data. Hydrologic and thermal parameters are determined and compared to the values obtained from laboratory measurements and conventional field test analysis.
Date: May 1, 1995
Creator: Finsterle, S.; Bodvarsson, G.S. & Chen, G.
System: The UNT Digital Library
The measurement and analysis of wavefront structure from large aperture ICF optics (open access)

The measurement and analysis of wavefront structure from large aperture ICF optics

This paper discusses the techniques, developed over the past year, for high spatial resolution measurement and analysis of the transmitted and/or reflected wavefront of large aperture ICF optical components. Parts up to 400 mm {times} 750 mm have been measured and include: laser slabs, windows, KDP crystals and lenses. The measurements were performed using state-of-the-art commercial phase shifting interferometers at a wavelength of 633 {mu}m. Both 1 and 2-D Fourier analysis have been used to characterize the wavefront; specifically the Power Spectral Density, (PSD), function was calculated. The PSDs of several precision optical components will be shown. The PSD(V) is proportional to the (amplitude){sup 2} of components of the Fourier frequency spectrum. The PSD describes the scattered intensity and direction as a function of scattering angle in the wavefront. The capability of commercial software is limited to 1-D Fourier analysis only. We are developing our own 2-D analysis capability in support of work to revise specifications for NIF optics. 2-D analysis uses the entire wavefront phase map to construct 2D PSD functions. We have been able to increase the signal-to-noise relative to 1-D and can observe very subtle wavefront structure.
Date: May 30, 1995
Creator: Wolfe, C. R. & Lawson, J. K.
System: The UNT Digital Library
POLARIZED PROTONS TRACKING IN THE AGS AND RHIC. (open access)

POLARIZED PROTONS TRACKING IN THE AGS AND RHIC.

A code, SPINK, to track polarized particles in a circular accelerator, in particular RHIC [1], is been used to: find conditions for safely crossing depolarizing resonances, using Siberian Snakes; find the best conditions to match the spin of the injected beam to the ring lattice; study the operation of Spin Rotators and study the beam-beam effects in a polarized proton collider.
Date: May 20, 1999
Creator: Luccio, A. U.
System: The UNT Digital Library
How much is energy R and D worth? (open access)

How much is energy R and D worth?

The value of energy technology R and D as an insurance investment to reduce the cost of climate change stabilization, oil price shocks, urban air pollution, and energy disruptions is estimated to be $5-8 billion/year in sum total. However, the total that is justified is actually less than this sum because some R and D is applicable to more than one risk. nevertheless, the total DOE investment in energy technology R and D (about $1.3 billion/year in FY97) seems easily justified by its insurance value alone; and, in fact, more might be warranted, particularly in the areas related to climate change and urban air pollution. This conclusion appears robust even if the private sector is assumed to be investing a comparable amount. Not counted is the value to the economy and to US competitiveness of better energy technologies that may result from the R and D; only the insurance value for reducing the cost of these four risks to society was estimated.
Date: May 6, 1997
Creator: Schock, R. N., LLNL
System: The UNT Digital Library
Construction monitoring activities in the ESF starter tunnel (open access)

Construction monitoring activities in the ESF starter tunnel

In situ design verification activities am being conducted in the North Ramp Starter Tunnel of the Yucca Mountain Project Exploratory Studies Facility. These activities include: monitoring the peak particle velocities and evaluating the damage to the rock mass associated with construction blasting, assessing the rock mass quality surrounding the tunnel, monitoring the performance of the installed ground support, and monitoring the stability of the tunnel. In this paper, examples of the data that have been collected and preliminary conclusions from the data are presented.
Date: May 1, 1994
Creator: Pott, J. & Carlisle, S.
System: The UNT Digital Library
Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses. (open access)

Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses.

A glass-bonded sodalite ceramic waste form is being developed for the long-term immobilization of salt wastes that are generated during spent nuclear fuel conditioning activities. A durable waste form is prepared by hot isostatic pressing (HIP) a mixture of salt-loaded zeolite powders and glass frit. A mechanistic description of the corrosion processes is being developed to support qualification of the CWF for disposal. The initial set of characterization tests included two standard tests that have been used extensively to study the corrosion behavior of high level waste (HLW) glasses: the Material Characterization Center-1 (MCC-1) Test and the Product Consistency Test (PCT). Direct comparison of the results of tests with the reference CWF and HLW glasses indicate that the corrosion behaviors of the CWF and HLW glasses are very similar.
Date: May 6, 1999
Creator: Ebert, W. L. & Lewis, M. A.
System: The UNT Digital Library