401 Matching Results

Search Results

Results: 1 - 24 next
open access

The effects of silicon doping on the performance of PMAN carbon anodes in Li-ion cells

Description: Carbons derived from polymethylacrylonitrile (PMAN) have been studied for use as intercalation anodes in Li-ion cells. The effect of Si doping upon the electrochemical performance of PMAN carbons was studied using tetravinylsilane (TVS) and tetramethysilane (TMS) as sources of Si during the formation of the PMAN precursors. The carbons were characterized by galvanostatic cycling, cyclic voltammetry, and complex impedance. The presence of 9 to 11 w/o Si in the PMAN lattice greatly increased the … more
Date: May 1, 1996
Creator: Guidotti, Ronald A.; Johnson, Bryan J. & Even, William, Jr.
Partner: UNT Libraries Government Documents Department
open access

Getting to necessary and sufficient-developing accident scenarios for risk assessment

Description: This paper presents a simple, systematic approach for developing accident scenarios using generic accident types. Result is a necessary and sufficient set of accident scenarios that can be used to establish the safety envelope for a facility or operation. Us of this approach along with the methodology of SAND95-0320 will yield more consistent accident analyses between facilities and provide a sound basis for allocating limited risk reduction resources.
Date: May 1, 1996
Creator: Mahn, Jeffrey A.
Partner: UNT Libraries Government Documents Department
open access

Expanding the role of internal facility assessments

Description: The US Air Force (USAF) Environmental Compliance Assessment and Management Program (ECAMP) is an effective and comprehensive system to evaluate environmental compliance at individual USAF installations. The ECAMP assessment is typically performed by a team of experts from the installation`s Major Command (MAJCOM) Headquarters, and is often augmented with technical contractor support. As directed by Air Force policy, an external ECAMP assessment is required at a minimum of every three years for … more
Date: May 1, 1996
Creator: Kolpa, Ronald L.; Levenson, James B. & Weaver, Marja A.
Partner: UNT Libraries Government Documents Department
open access

Evaluating the quality and effectiveness of hazardous waste training programs

Description: An installation`s compliance with Resource Conservation and Recovery Act (RCRA) hazardous waste regulations is strongly dependent on the knowledge, skill, and behavior of all individuals involved in the generation and management of hazardous waste. Recognizing this, Headquarters Air Force Materiel Command (HQ/AFMC) determined that an in-depth evaluation of hazardous waste training programs at each AFMC installation was an appropriate element in assessing the overall effectiveness of installatio… more
Date: May 1, 1996
Creator: Kolpa, Ronald L.; Haffenden, Rebecca A. & Weaver, Marja A.
Partner: UNT Libraries Government Documents Department
open access

A general protocol for restoration of entire river catchments

Description: Large catchment basins may be viewed as ecosystems with interactive natural and cultural attributes. Stream regulation severs ecological connectivity between channels and flood plains by reducing the range of natural flow and temperature variation, reduces the capacity of the ecosystem to sustain native biodiversity and bioproduction and promotes proliferation of non-native biota. However, regulated rivers regain normative attributes, which promote recovery of native biota, as distance from the… more
Date: May 28, 1996
Creator: Stanford, Jack A.; Frissell, Christopher A.; Ward, J. V.; Liss, William J.; Coutant, Charles C.; Williams, Richard N. et al.
Partner: UNT Libraries Government Documents Department
open access

Selective, pulsed CVD of platinum on microfilament gas sensors

Description: A post-processing, selective micro-chemical vapor deposition (``micro-CVD``) technology for the deposition of catalytic films on surface-micromachined, nitride-passivated polysilicon filaments has been investigated. Atmospheric pressure deposition of Pt on microfilaments was accomplished by thermal decomposition of Pt acetylacetonate; deposition occurs selectively only on those filaments which are electrically heated. Catalyst morphology, characterized by SEM, can be controlled by altering depo… more
Date: May 1, 1996
Creator: Manginell, Ronald P.; Smith, James H.; Ricco, Antonio J.; Moreno, Daniel J.; Hughes, Robert C.; Huber, Robert J. et al.
Partner: UNT Libraries Government Documents Department
open access

New developments in fluorofullerenes chemistry

Description: Flurofullerenes were among the first chemical derivatives prepared from new spherical forms of carbon, yet it took 3 years of research to isolate the first single compound, C{sub 60}F{sub 48}. Subsequent studies provided a better understanding of physical and chemical properties of this compound. Here we present new data concerning synthesis, reactions, and properties of C{sub 60}F{sub 48}.
Date: May 1, 1996
Creator: Gakh, Andrei A.; Sachleben, Richard A.; Hagaman, Edward W. & Tuinman, Albert A.
Partner: UNT Libraries Government Documents Department
open access

Development of sol-gel derived coating for NICALON{sup TM}/SiC composites

Description: Mullite and aluminum titanate precursor polymeric sols were developed for applying as coatings on Nicalon{trademark} fabrics and tows. A Nicalon{trademark}/SiC composite with a mullite interface was fabricated. The mullite precursor interface coatings were applied by a vacuum infiltration method and the SiC matrix was deposited by a forced flow chemical vapor infiltration process. Thin, uniform mullite interface coatings were obtained. However, the Nicalon{trademark}/SiC composite exhibited bri… more
Date: May 1, 1996
Creator: Shanmugham, S.; Liaw, P. K.; Stinton, D. P.; Besmann, T. M.; More, K. L.; Bleier, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Experimental Investigation of the Classical Rayleigh-Taylor Instability

Description: The evolution of the Rayleigh-Taylor (RT) instability in a compressible medium has been investigated at an accelerating embedded interface and at the ablation front in a series of experiments on the Nova laser. The x-ray drive generated in a gold hohlraum ablatively accelerated a planar target consisting of a doped plastic pusher backed by a higher density titanium payload with perturbations placed at the plastic-Ti interface. The targets were diagnosed by face-on and side-on radiography. In pr… more
Date: May 21, 1996
Creator: Budil, K. S.; Remington, B. A.; Peyser, T. A.; Mikaelian, K. O.; Rubenchik, A. M.; Berning, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Spatial Resolution of Gated X-Ray Pinhole Cameras

Description: The new camera FXI was investigated. Spatial resolution, or its Fourier transform, the modulation transfer function (MTF), is critical for quantitative interpretation of recent hydrodynamic instability data taken on the Nova laser. We have taken data corresponding to backlit straight edges, pinholes, and grids, both on the bench and {ital in}{ital situ} on Nova. For both the pinhole and edge data, the MTF at all wavelengths of interest can be deduced from a single image. Grids are of more limit… more
Date: May 15, 1996
Creator: Robey, H. F.; Budil, K. S. & Remington, B. A.
Partner: UNT Libraries Government Documents Department
open access

What is the potential predictability of seasonal floods and droughts?

Description: The potential predictability (PP) of seasonal anomalies in continental hydrology may be thought of as the upper bound in forecast accuracy to be expected when the state of the oceans is known perfectly. We assume that the PP of the seasonal anomalies of continental hydrology is related to their degree of reproducibility in the presence of identical ocean boundary conditions across a number of simulations. In this study, the PP of seasonal anomalies in surface hydrological variables is estimated… more
Date: May 1, 1996
Creator: Phillips, T. J.
Partner: UNT Libraries Government Documents Department
open access

Testing of an impedance heating system for solar power tower applications

Description: A non-conventional type of heating system is being tested at Sandia National Laboratories for solar thermal power tower applications. In this system, called impedance heating, electric current flows directly through the pipe to maintain the desired temperature. The pipe becomes the resistor where the heat is generated. Impedance heating has many advantages over previously used mineral insulated (MI) heat trace. An impedance heating system should be much more reliable than heat trace cable since… more
Date: May 1, 1996
Creator: Pacheco, James E. & Kolb, William J.
Partner: UNT Libraries Government Documents Department
open access

A three-dimensional nodal neutron kinetics capability for relaps

Description: The incorporation of a three-dimensional neutron kinetics capability into the DOE version of the RELAP5/MOD3.2 reactor safety code is discussed. A brief discussion of the kinetics method is given along with a discussion of the cross section parameterization models available in RELAP5/MOD3.2. The RELAP5/MOD3.2 code is then used to perform calculations of the NEACRP rod ejection and rod withdrawal benchmarks, and results are presented.
Date: May 1, 1996
Creator: Judd, J. L. & Weaver, W. L.
Partner: UNT Libraries Government Documents Department
open access

High current RF shield for PEP-II vacuum system expansion joint

Description: A novel RF shield was developed for the circular expansion joint used throughout the PEP-II vacuum system straight sections. Existing RF shield designs, used in accelerators/storage rings throughout the world, have been the source of many failures at beam currents much smaller than the 3 amps planned for PEP-II. This RF shield uses a unique spring-loaded finger mechanism to maintain proper electrical contact across the joint, accommodate 1.5 mm transverse and 32 mm longitudinal excursions, whil… more
Date: May 1996
Creator: Belser, F. C.; Berg, J. D. & Kerns, J.
Partner: UNT Libraries Government Documents Department
open access

A fast CCD detector for charge exchange recombination spectroscopy on the DIII-D tokamak

Description: Charge Exchange Recombination (CER) spectroscopy has become a standard diagnostic for tokamaks. CER measurements have been used to determine spatially and temporally resolved ion temperature, toroidal and poloidal ion rotation speed, impurity density and radial electric field. Knowledge of the spatial profile and temporal evolution of the electric field shear in the plasma edge is crucial to understanding the physics of the L to H transition. High speed CER measurements are also valuable for Ed… more
Date: May 1996
Creator: Thomas, D. M.; Burrell, K. H.; Groebner, R. J. & Gohil, P.
Partner: UNT Libraries Government Documents Department
open access

Recent advances in phosphate laser glasses for high power applications

Description: Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bu… more
Date: May 14, 1996
Creator: Campbell, J.H.
Partner: UNT Libraries Government Documents Department
open access

Forming and smoothing D{sub 2} and HD layers for ICF by infra-red heating

Description: We describe a technique to form and smooth uniform solid D{sub 2}, HD or DT layers for inertial confinement fusion targets. Pumping the infrared (IR) collision induced vibration-rotation band generates a bulk heating of the solid. Shadowgraphs reveal that this bulk heat quickly redistributes the solid into a relatively uniform layer depending on the IR intensity profile. Measured redistribution time constants are used to determine the conversion efficiency of IR light into bulk heat. Phase shif… more
Date: May 31, 1996
Creator: Collins, G.W.; Tiszauer, D.; Feit, M.; Mapoles, E.R.; Bernat, T.P.; Bittner, D.N. et al.
Partner: UNT Libraries Government Documents Department
open access

Proceedings from a Workshop on Ecological Carrying Capacity of Salmonids in the Columbia River Basin : Measure 7.1A of the Northwest Power Planning Council`s 1994 Fish and Wildlife Program : Report 3 of 4, Final Report.

Description: This report contains the proceedings of a workshop held during 1995 in Portland, Oregon. The objective of the workshop was to assemble a group of experts that could help us define carrying capacity for Columbia River Basin salmonids. The workshop was one activity designed to answer the questions asked in Measure 7.1A of the Council`s Fish and Wildlife Program. Based, in part, on the information we learned during the workshop we concluded that the approach inherent in 7.1A will not increase unde… more
Date: May 1996
Creator: Johnson, Gary E.; Neitzel, D. A. & Mavros, William V.
Partner: UNT Libraries Government Documents Department
open access

Recent progress in InGaAsSb/GaSb TPV devices

Description: AstroPower is developing InGaAsSb thermophotovoltaic (TPV) devices. This photovoltaic cell is a two-layer epitaxial InGaAsSb structure formed by liquid-phase epitaxy on a GaSb substrate. The (direct) bandgap of the In{sub 1{minus}x}Ga{sub x}As{sub 1{minus}y}Sb{sub y} alloy is 0.50 to 0.55 eV, depending on its exact alloy composition (x,y); and is closely lattice-matched to the GaSb substrate. The use of the quaternary alloy, as opposed to a ternary alloy--such as, for example InGaAs/InP--permit… more
Date: May 1, 1996
Creator: Shellenbarger, Z. A.; Mauk, M. G.; DiNetta, L. C. & Charache, G. W.
Partner: UNT Libraries Government Documents Department
open access

Working with the superabrasives industry to optimize tooling for grinding brittle materials

Description: The optics manufacturing industry is undertaking a significant modernization, as computer-numeric-controlled (CNC) equipment is joining or replacing open-loop equipment and hand lapping/polishing on the shop floor. Several prototype CNC lens grinding platforms employing ring tools are undergoing development and demonstration at the Center for Optics Manufacturing in Rochester, NY, and several machine tool companies have CNC product lines aimed at the optics industry. Benefits to using CNC ring … more
Date: May 1, 1996
Creator: Taylor, J. S.; Piscotty, M. A.; Blaedel, K. L. & Gray, F. A.
Partner: UNT Libraries Government Documents Department
open access

Positron beam lifetime spectroscopy of atomic scale defect distributions in bulk and microscopic volumes

Description: We are developing a defect analysis capability based on two positron beam lifetime spectrometers: the first is based on a 3 MeV electrostatic accelerator and the second on our high current linac beam. The high energy beam lifetime spectrometer is operational and positron lifetime analysis is performed with a 3 MeV positron beam on thick samples. It is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for {ital in}{ital situ} measurements. A seco… more
Date: May 1, 1996
Creator: Howell, R. H.; Cowan, T. E.; Hartley, J.; Sterne, P. & Brown, B.
Partner: UNT Libraries Government Documents Department
open access

Photoelectron emission microscopy and its application to the study of polymer surfaces

Description: The X-ray Photoelectron Emission Microscopy (X-PEEM) at the Advanced Light Source (ALS) has a spatial resolution of 0.2 microns at an accelerating voltage of 12kV. The tunability of the photon energy is used to provide chemical state information using near edge X-ray absorption fine structure (NEXAFS) spectroscopy on the sub-micrometer scale. The homogeneity of thin films of polymer blends was studied for various film thicknesses. The polystyrene/polyvinylmethylether film of 194 {angstrom} show… more
Date: May 1, 1996
Creator: Cossy-Favre, A.; Diaz, J.; Anders, S. & Padmore, H.A.
Partner: UNT Libraries Government Documents Department
open access

The Hanford spent nuclear metal fuel multi-canister overpack and vacuum drying {ampersand} hot conditioning process

Description: Nuclear production reactors operated at the U.S. Department of Energy`s Hanford Site from 1944 until 1988 to produce plutonium. Most of the irradiated fuel from these reactors was processed onsite to separate and recover the plutonium. When the processing facilities were closed in 1992, about 1,900 metric tons of unprocessed irradiated fuel remained in storage. Additional fuel was irradiated for research purposes or was shipped to the Hanford Site from offsite reactor facilities for storage or … more
Date: May 15, 1996
Creator: Irwin, J.J.
Partner: UNT Libraries Government Documents Department
open access

Improved operation of the Michelson interferometer ECE diagnostic on DIII-D

Description: The measurement of accurate temperature profiles is critical for transport analysis and equilibrium reconstruction in the DIII-D tokamak. Recent refinements in the Michelson interferometer diagnostic have produced more precise electron temperature measurements from electron cyclotron emission and made them available for a wider range of discharge conditions. Replacement of a lens-relay with a low-loss corrugated waveguide transmission system resulted in an increase in throughput of 6 dB and red… more
Date: May 1, 1996
Creator: Austin, M. E.; Ellis, R. F.; Doane, J. L. & James, R. A.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen