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[Tennessee Health Studies Agreement] Releases of contaminants from Oak Ridge facilites and risks to public health
Tennessee Health Studies Agreement-Releases of Contaminants from Oak Ridge Facilities
Date:
September 30, 1999
Creator:
741-0388, Patrick Lippford-Tennessee Department of Health (615)
Object Type:
Report
System:
The UNT Digital Library
AntiReflection Coating D
Analytical expressions used to optimize AR coatings for single junction solar cells are extended for use in monolithic, series interconnected multi-junction solar cell AR coating design. The result is an analytical expression which relates the solar cell performance (through J{sub sc}) directly to the AR coating design through the device reflectance. It is also illustrated how AR coating design be used to provide an additional degree of freedom for current matching multi-junction devices.
Date:
September 23, 1999
Creator:
AIKEN,DANIEL J.
Object Type:
Article
System:
The UNT Digital Library
Investigation of Sodium Distribution in Phosphate Glasses Using Spin-Echo {sup 23}Na NMR
The spatial arrangement of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O(100-x)P{sub 2}O{sub 5} (x<55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases non-linearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model and a pair-wise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS model, it is demonstrated that the slight non-linear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and non-clustered distributions becomes more difficult at higher …
Date:
September 16, 1999
Creator:
ALAM, TODD M.; BOYLE, TIMOTHY J.; BROW, RICHARD K.; CLICK, CAROL C.; CONZONE, SAM; McLAUGHLIN, JAY et al.
Object Type:
Article
System:
The UNT Digital Library
Corrosion of Uranium in Desert Soil, with Application to GCD Source Term M
Uranium fragments from the Sandia Sled Track were studied as analogues for weapons components and depleted uranium buried at the Greater Confinement Disposal (GCD) site in Nevada. The Sled Track uranium fragments originated as weapons mockups and counterweights impacted on concrete and soil barriers, and experienced heating and fragmentation similar to processes thought to affect the Nuclear Weapons Accident Residues (NWAR) at GCD. Furthermore, the Sandia uranium was buried in unsaturated desert soils for 10 to 40 years, and has undergone weathering processes expected to affect the GCD wastes. Scanning electron microscopy, X-ray diffraction and microprobe analyses of the fragments show rapid alteration from metals to dominantly VI-valent oxy-hydroxides. Leaching studies of the samples give results consistent with published U-oxide dissolution rates, and suggest longer experimental periods (ca. 1 year) would be required to reach equilibrium solution concentrations. Thermochemical modeling with the EQ3/6 code indicates that the uranium concentrations in solutions saturated with becquerelite could increase as the pore waters evaporate, due to changes in carbonate equilibria and increased ionic strength.
Date:
September 1, 1999
Creator:
ANDERSON, HOWARD L.; BACA, JULIANNE; KRUMHANSL, JAMES L.; STOCKMAN, HARLAN W. & THOMPSON, MOLLIE E.
Object Type:
Report
System:
The UNT Digital Library
Bipolaron Hopping Conduction in Boron Carbides
The electrical conductivities of boron carbides, B{sub 12+x}C{sub 3{minus}x} with 0.1 < x < 1.7, between 300 and 1200K suggest the hopping of a nearly temperature-independent density of small (bi)polarons. The activation energies of the nobilities are low, {approx} 0.16 eV, and are nearly independent of the composition. At lower temperatures, conductivities have non-Arrhenius temperature dependencies and strong sensitivity to carbon concentration. Percolative aspects of low-temperature hopping are evident in this sensitivity to composition. Boron carbides' Seebeck coefficients are anomalous in that (1) they are much larger than expected from boron carbides' large carrier densities and (2) they depend only weakly on the carrier density. Carrier-induced softening of local vibrations gives contributions to the Seebeck coefficient that mirror the magnitudes and temperature dependencies found in boron carbides.
Date:
September 20, 1999
Creator:
ASELAGE, TERRENCE L.; EMIN, D. & MCCREADY, STEVEN S.
Object Type:
Article
System:
The UNT Digital Library
Current Performance of the SLD VXD3
During 1996, the SLD collaboration completed construction and began operation of a new charge-coupled device (CCD) vertex detector (VXD3). Since then, its performance has been studied in detail and a new topological vertexing technique has been developed. In this paper, we discuss the design of VXD3, procedures for aligning it, and the tracking and vertexing improvements that have led to its world-record performance.
Date:
September 14, 1999
Creator:
Abe, Toshinori
Object Type:
Report
System:
The UNT Digital Library
Abilene Philharmonic Playbill: September 25-October 30, 1999
Program for an Abilene Philharmonic concert that ran from September 25th to October 30th during the 50th season. It includes information about the pieces performed, artists and musicians, and advertising from local companies.
Date:
September 1999
Creator:
Abilene Philharmonic
Object Type:
Pamphlet
System:
The Portal to Texas History
Low Speed Carbon Deposition Process for Hermetic Optical Fibers
For optical fibers used in adverse environments, a carbon coating is frequently deposited on the fiber surface to prevent water and hydrogen ingression that lead respectively to strength degradation through fatigue and hydrogen-induced attenuation. The deposition of a hermetic carbon coating onto an optical fiber during the draw process holds a particular challenge when thermally-cured specialty coatings are subsequently applied because of the slower drawing rate. In this paper, we report on our efforts to improve the low-speed carbon deposition process by altering the composition and concentration of hydrocarbon precursor gases. The resulting carbon layers have been analyzed for electrical resistance, Raman spectra, coating thickness, and surface roughness, then compared to strength data and dynamic fatigue behavior.
Date:
September 29, 1999
Creator:
Abramczyk, Jaroslaw; Arthur, Sara E.; Tallant, David R.; Hikansson, Adam S.; Lindholm, Eric A. & Lo, Jie
Object Type:
Article
System:
The UNT Digital Library
High Precision Droplet Based New Form Manufacturing
In collaboration with the University of California at Irvine (UCI), we are working on a new technology that relies on the precise deposition of nanoliter molten-metal droplets that are targeted onto a substrate by electrostatic charging and deflection. By this way, three-dimensional (3D) structural materials can be manufactured microlayer by microlayer. Because the volume of the droplets are small, they rapidly solidify on impact, bringing forth a material component with fine grain structures which lead to enhanced material properties (e.g., strength). UCI is responsible for an experimental investigation of the manufacturing feasibility of this process. LLNL has unique expertise in the computational modeling of 3D heat transfer and solid mechanics and has the large-scale computer resources necessary to model this large system. Process modeling will help move this technology from the bench-top to an industrial process. Applications at LLNL include rapid prototyping of metal parts and manufacturing new alloys by co-jetting different metals.
Date:
September 16, 1999
Creator:
Aceves, S.; Hadjiconstantinou, N.; Miller, W. O.; Orme, M.; Sahai, V. & Shapiro, A. B.
Object Type:
Report
System:
The UNT Digital Library
Modeling Transport in Gas Chromatography Columns for the Micro-ChemLab
The gas chromatography (GC) column is a critical component in the microsystem for chemical detection ({mu}ChemLab{trademark}) being developed at Sandia. The goal is to etch a meter-long GC column onto a 1-cm{sup 2} silicon chip while maintaining good chromatographic performance. Our design strategy is to use a modeling and simulation approach. We have developed an analytical tool that models the transport and surface interaction process to achieve an optimized design of the GC column. This analytical tool has a flow module and a separation module. The flow module considers both the compressibility and slip flow effects that may significantly influence the gas transport in a long and narrow column. The separation module models analyte transport and physico-chemical interaction with the coated surface in the GC column. It predicts the column efficiency and performance. Results of our analysis will be presented in this paper. In addition to the analytical tool, we have also developed a time-dependent adsorption/desorption model and incorporated this model into a computational fluid dynamics (CFD) code to simulate analyte transport and separation process in GC columns. CFD simulations can capture the complex three-dimensional flow and transport dynamics, whereas the analytical tool cannot. Different column geometries have been studied, …
Date:
September 1, 1999
Creator:
Adkins, Douglas R.; Frye-Mason, Gregory Charles; Hudson, Mary L.; Kottenstette, Richard; Matzke, Carolyn M.; Salinger, Andrew G. et al.
Object Type:
Article
System:
The UNT Digital Library
Wakefield and Beam Centering Measurements of a Damped and Detuned X-Band Accelerator Structure
In the Next Linear Collider (NLC) design, X-Band (11.4 GHz) accelerator structures are used to accelerate multibunch beams to several hundred GeV. Although these structures allow for high gradient operation, their strong deflecting modes impose a number of operational constraints. In particular, the long-range transverse wakefields generated by the bunches need to be reduced by about two orders of magnitude to prevent significant beam breakup. During the past five years, a reduction scheme that employs both detuning and damping of the structure dipole modes has been developed to meet this requirement. Several prototype Damped and Detuned Structures (DDS) have been built to test and refine this scheme. The wakefield of the latest version, DDS3, has recently been measured in the Accelerator Structure Setup (ASSET) facility at SLAC. In this paper, we present these results together with predictions based on an equivalent circuit model of the structure. We also present ASSET studies in which the beam-induced dipole signals that are coupled out for damping purposes are used to center the beam in the structure.
Date:
September 14, 1999
Creator:
Adolphsen, Chris
Object Type:
Report
System:
The UNT Digital Library
Single-particle states in transcurium nuclei.
Identification of single-particle states in the heaviest known nuclei is important because their energies can be used to test the single-particle potential in these high-Z elements. These states can be identified by studying the decay schemes of very heavy odd-mass nuclides. For neutrons, the heaviest odd-mass nuclide available in milliCurie quantities is the 20-h {sup 255}Fm and for protons the heaviest nuclide available is the 20-d {sup 253}Es. These two isotopes were obtained from the Transplutonium Element Production Program at Oak Ridge and their spectra were measured with high-resolution germanium spectrometers. From the results of these measurements we have identified states in {sup 251}Cf and {sup 249}Bk up to 1 MeV excitation energy.
Date:
September 30, 1999
Creator:
Ahmad, I.
Object Type:
Article
System:
The UNT Digital Library
Dynamics of H abstraction from alcohols (CH3OH, C2H5OH and 2-C3H7OH) using velocity map imaging in crossed molecular beams
The crossed beam reactions of ground state Cl ({sup 2}P{sub 3/2}) atoms with alcohols (CH{sub 3}OH, C{sub 2}H{sub 5}OH and 2-C{sub 3}H{sub 7}OH) have been studied using the technique of velocity map imaging (VELMI). The corresponding hydroxyalkyl radical was detected via single photon ionization using 157 nm laser light. The double differential cross sections were obtained at collision energies of 8.7 kcal/mol for methanol, 6.0 and 9.7 kcal/mol for ethanol, and 11.9 kcal/mol for 2-propanol. In all cases, the scattering was predominantly in the backward-sideways direction suggesting direct rebound dynamics, with varying amounts of sideways-scattering. In the case of methanol, the angular distributions were predominantly in the sideways-backward direction with respect to the incoming alcohol beam. Scattering was into the backward hemisphere at the lower collision energy for ethanol, with enhancement of sideways scattering with an increase in collision energy. Isoropanol gave scattering predominantly in the backward direction. Coupling between the translational energy and angular distributions was particularly significant for ethanol at the lower collision energy. All of the translational energy distributions peaked at about 6 kcal/mol and on average 30-40% of the available energy was deposited into product translation for all the alcohols studied. These results are contrasted with …
Date:
September 1, 1999
Creator:
Ahmed, M.; Peterka, D. S. & Suits, A. G.
Object Type:
Article
System:
The UNT Digital Library
Partial Oxidation Fuel Reforming for Automotive Power Systems
For widespread use of fuel cells to power automobiles in the near future, it is necessary to convert gasoline or other transportation fuels to hydrogen on-board the vehicle. Partial oxidation reforming is particularly suited to this application as it eliminates the need for heat exchange at high temperatures. Such reformers offer rapid start and good dynamic performance. Lowering the temperature of the partial oxidation process, which requires the development of a suitable catalyst, can increase the reforming efficiency. Catalytic partial oxidation (or autothermal) reformers and non-catalytic partial oxidation reformers developed by various organizations are presently undergoing testing and demonstration. This paper summarizes the process chemistries as well as recent test data from several different reformers operating on gasoline, methanol, and other fuels.
Date:
September 7, 1999
Creator:
Ahmed, S.; Chalk, S.; Krumpelt, M.; Kumar, R. & Milliken, J.
Object Type:
Article
System:
The UNT Digital Library
Gas-to-liquids synthetic fuels for use in fuel cells : reformability, energy density, and infrastructure compatibility.
The fuel cell has many potential applications, from power sources for electric hybrid vehicles to small power plants for commercial buildings. The choice of fuel will be critical to the pace of its commercialization. This paper reviews the various liquid fuels being considered as an alternative to direct hydrogen gas for the fuel cell application, presents calculations of the hydrogen and carbon dioxide yields from autothermal reforming of candidate liquid fuels, and reports the product gas composition measured from the autothermal reforming of a synthetic fuel in a micro-reactor. The hydrogen yield for a synthetic paraffin fuel produced by a cobalt-based Fischer-Tropsch process was found to be similar to that of retail gasoline. The advantages of the synthetic fuel are that it contains no contaminants that would poison the fuel cell catalyst, is relatively benign to the environment, and could be transported in the existing fuel distribution system.
Date:
September 8, 1999
Creator:
Ahmed, S.; Kopasz, J. P.; Russell, B. J. & Tomlinson, H. L.
Object Type:
Article
System:
The UNT Digital Library
Improving paper machine efficiency through on-line control of stock delivery, headbox and forming hydrodynamics
None
Date:
September 30, 1999
Creator:
Aidun, Cyrus K.
Object Type:
Report
System:
The UNT Digital Library
Emissions Inventory Report Summary Reporting Requirements for the New Mexico Administrative Code, Title 20, Chapter 2, Part 73 (20 NMAC 2.73) for Calendar Year 1998
Los Alamos National Laboratory (the Laboratory) is subject to emissions reporting requirements for regulated air contaminants under Title 20 of the New Mexico Administrative Code, Chapter 2, Part 73 (20 NMAC 2.73), Notice of Intent and Emissions Inventory Requirements. The Laboratory has the potential to emit 100 tons per year of suspended particulate matter, nitrogen oxides, carbon monoxide, sulfur oxides, and volatile organic compounds. For 1998, combustion products from the industrial sources contributed the greatest amount of criteria air pollutants from the Laboratory. Research and development activities contributed the greatest amount of volatile organic compounds. Emissions of beryllium and aluminum were reported for activities permitted under 20 NMAC 2.72 Construction Permits.
Date:
September 1, 1999
Creator:
Air Quality Group, ESH-17
Object Type:
Report
System:
The UNT Digital Library
X-ray diffraction studies using diamond coated rhenium gasket to megabar pressures
X-ray diffraction studies at megabar pressures are limited by the sample thickness between the diamond anvils. High strength gaskets are desirable to improve the quality of x-ray diffraction data. We present a technique which employs a microwave plasma chemical vapor deposited diamond layer on one side of a rhenium gasket. As a test case, we show energy dispersive x-ray diffraction data on rare earth metal neodymium to 153 GPa using a synchrotron source. The increased sample thickness results in an unambiguous crystal structure determination of a monoclinic phase in neodymium above 75 GPa. [chemical vapor deposition, diamond, rhenium gasket, x-ray diffraction, neodymium]
Date:
September 30, 1999
Creator:
Akella, J; Catledge, S A; Chesnut, G N; Prokop, H; Vohra, Y K & Weir, S T
Object Type:
Article
System:
The UNT Digital Library
Cell Placement in a CDMA Network
This presentation discusses research on cell placement in a CDMA network. In order to enable iterative cell placement the authors use a computationally efficient iterative process to calculate the inter-cell and intra-cell interferences as a function of pilot-signal power and base station location.
Date:
September 1999
Creator:
Akl, Robert G.; Hegde, Manju V.; Naraghi-Pour, Mort & Min, Paul S.
Object Type:
Presentation
System:
The UNT Digital Library
Capture Zone Analyses of Two Airlift Recirculation Wells in the Southern Sector of A/M Area
This report documents a series of capture zone analyses performed to access the expected overall performance of two (of the twelve) vertical airlift recirculation wells (ARWs) (specifically, SSR-011 and SRR-012) located in the Southern Sector of A/M Area.
Date:
September 14, 1999
Creator:
Aleman, S. E.
Object Type:
Report
System:
The UNT Digital Library
Design and testing of cryogenic target systems
General Atomics (GA) together with the University of Rochester/Laboratory for Laser Energetics (UR/LLE) and Los Alamos National Laboratory (LANL), has designed the OMEGA Cryogenic Target System. This system fills, cools, and layers DT targets and places them in the center of the OMEGA Target Chamber. All equipment was procured, assembled, and tested at GA and UR/LLE. GA along with Lawrence Livermore National Laboratory and LANL is designing a test unit to evaluate the key process parameters and design issues associated with fielding cryogenic targets on the National Ignition Facility.
Date:
September 9, 1999
Creator:
Alexander, N. B.; Baugh, W. A.; Bernat, T. P.; Besenbruch, G. E.; Boline, K. K.; Brown, L. C. et al.
Object Type:
Article
System:
The UNT Digital Library
ALPS - advanced limiter-divertor plasma-facing systems.
The Advanced Limiter-divertor Plasma-facing Systems (ALPS) program was initiated in order to evaluate the potential for improved performance and lifetime for plasma-facing systems. The main goal of the program is to demonstrate the advantages of advanced limiter/divertor systems over conventional systems in terms of power density capability, component lifetime, and power conversion efficiency, while providing for safe operation and minimizing impurity concerns for the plasma. Most of the work to date has been applied to free surface liquids. A multi-disciplinary team from several institutions has been organized to address the key issues associated with these systems. The main performance goals for advanced limiters and diverters are a peak heat flux of >50 MW/m{sup 2},elimination of a lifetime limit for erosion, and the ability to extract useful heat at high power conversion efficiency ({approximately}40%). The evaluation of various options is being conducted through a combination of laboratory experiments, modeling of key processes, and conceptual design studies. The current emphasis for the work is on the effects of free surface liquids on plasma edge performance.
Date:
September 15, 1999
Creator:
Allain, J. P.; Bastasz, R.; Brooks, J. N.; Evans, T.; Hassanein, A.; Luckhardt, S. et al.
Object Type:
Article
System:
The UNT Digital Library
PROPERTIES AND PERFORMANCE OF CEMENT-BASED GROUTS FOR GEOTHERMAL HEAT PUMP APPLICATIONS.
None
Date:
September 30, 1999
Creator:
Allan, M. L.
Object Type:
Report
System:
The UNT Digital Library
Sorption and diffusion studies of Pu(IV) and Pu(V)-EDTA onto and through Hanford soil
Plutonium production at U.S. Department of Energy Hanford site has created massive amounts of radioactive and mixed wastes. Over 1.3 trillion liters of liquid waste have been discharged into the ground, the largest part of which has been absorbed by the upper soil layers with a small fraction migrating into the groundwater. Approximately 350 million liters of other low and high-level mixed wastes were stored in underground tanks between 1944 and 1980. These tanks contain organic materials that were introduced during the production and processing of plutonium, such as ethylenediametetraacetic acid (EDTA), tributyl phosphate, hexone, paraffin hydrocarbon and other minor organic and inorganic components. The quantity of EDTA is estimated to be 83 metric tons in the underground tanks. Several single-shell tanks are known or suspected to have leaked. It was reported that since 1995, approximately four million liters of mixed waste might have entered the soil beneath the single-shell tanks. This volume of waste is estimated to contain as much as one million curies of radioactivity.
Date:
September 15, 1999
Creator:
Allen, P G; Hakem, N L & Sylwester, E R
Object Type:
Article
System:
The UNT Digital Library