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  Partner: UNT Libraries Government Documents Department
 Decade: 1990-1999
 Year: 1999
A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors

A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors

Date: June 17, 1999
Creator: Bartel, Timothy J.; Economou, Demetre & Johannes, Justine E.
Description: This paper will focus on the methodology of using a 2D plasma Direct Simulation Monte Carlo technique to simulate the species transport in an inductively coupled, low pressure, chemically reacting plasma system. The pressure in these systems is typically less than 20 mtorr with plasma densities of approximately 10{sup 17} {number_sign}/m{sup 3} and an ionization level of only 0.1%. This low ionization level tightly couples the neutral, ion, and electron chemistries and interactions in a system where the flow is subsonic. We present our strategy and compare simulation results to experimental data for Cl{sub 2} in a Gaseous Electronics Conference (GEC) reference cell modified with an inductive coil.
Contributing Partner: UNT Libraries Government Documents Department
3-D Finite Element Analyses of the Egan Cavern Field

3-D Finite Element Analyses of the Egan Cavern Field

Date: February 1, 1999
Creator: Klamerus, E.W. & Ehgartner, B.L.
Description: Three-dimensional finite element analyses were performed for the two gas-filled storage caverns at the Egan field, Jennings dome, Louisiana. The effects of cavern enlargement on surface subsidence, storage loss, and cavern stability were investigated. The finite element model simulated the leaching of caverns to 6 and 8 billion cubic feet (BCF) and examined their performance at various operating conditions. Operating pressures varied from 0.15 psi/ft to 0.9 psi/ft at the bottom of the lowest cemented casing. The analysis also examined the stability of the web or pillar of salt between the caverns under differential pressure loadings. The 50-year simulations were performed using JAC3D, a three dimensional finite element analysis code for nonlinear quasistatic solids. A damage criterion based on onset of dilatancy was used to evaluate cavern instability. Dilation results from the development of microfractures in salt and, hence, potential increases in permeability onset occurs well before large scale failure. The analyses predicted stable caverns throughout the 50-year period for the range of pressures investigated. Some localized salt damage was predicted near the bottom walls of the caverns if the caverns are operated at minimum pressure for long periods of time. Volumetric cavern closures over time due to creep were ...
Contributing Partner: UNT Libraries Government Documents Department
3-D Measurement of Deformation Microstructure of Al(0.2%)Mg Using Submicron Resolution White X-Ray Microbeams

3-D Measurement of Deformation Microstructure of Al(0.2%)Mg Using Submicron Resolution White X-Ray Microbeams

Date: November 29, 1999
Creator: Larson, B. C.; tamura, N.; Chung, J.-S.; Ice, G. E.; Budai, J. D.; Tischler, J. Z. et al.
Description: We have used submicron-resolution white x-ray microbeams on the MHATT-CAT beamline 7-ID at the Advanced Photon Source to develop techniques for three-dimensional investigation of the deformation microstructure in a 20% plane strain compressed Al(0.2%)Mg tri-crystal. Kirkpatrick-Baez mirrors were used to focus white radiation from an undulator to a 0.7 x 0.7 {micro}m{sup 2} beam that was scanned over bi- and tri-crystal regions near the triple-junction of the tri-crystal. Depth resolution along the x-ray microbeam of less than 5 microns was achieved by triangulation to the diffractibn source point using images taken at a series of CCD distances from the microbeam. Computer indexing of the deformation cell structure in the bi-crystal region provided orientations of individual subgrains to {approximately}0.01 degrees, making possible detailed measurements of the rotation axes between individual cells.
Contributing Partner: UNT Libraries Government Documents Department
3-D Ray-tracing and 2-D Fokker-Planck Simulations of Radiofrequency Application to Tokamak Plasmas

3-D Ray-tracing and 2-D Fokker-Planck Simulations of Radiofrequency Application to Tokamak Plasmas

Date: May 1, 1999
Creator: Cardinali, A.; Paoletti, F. & Bernabei, S.
Description: A state of the art numerical tool has been developed to simulate the propagation and the absorption of coexisting different types of waves in a tokamak geometry. The code includes a numerical solution of the three-dimensional (R, Z, {Phi}) toroidal wave equation for the electric field of the different waves in the WKBJ approximation. At each step of integration, the two-dimensional (v{sub {parallel}}, v{sub {perpendicular}}) Fokker-Planck equation is solved in the presence of quasilinear diffusion coefficients. The electron Landau damping of the waves is modeled taking into account the interaction of the wave electric fields with the quasilinearly modified distribution function. Consistently, the code calculates the radial profiles of non-inductively generated current densities, the transmitted power traces and the total power damping curves. Synergistic effects among the different type of waves (e.g., lower hybrid and ion Bernstein waves) are studied through the separation of the contributions of the single wave from the effects due to their coexistence.
Contributing Partner: UNT Libraries Government Documents Department
3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution

3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution

Date: July 8, 1999
Creator: Fleming, J.G. & Lin, Shawn-Yu
Description: Three-dimensional photonic lattices are engineered materials which are the photonic analogues of semiconductors. These structures were first proposed and demonstrated in the mid-to-late 1980's. However, due to fabrication difficulties, lattices active in the infrared are only just emerging. Wide ranges of structures and fabrication approaches have been investigated. The most promising approach for many potential applications is a diamond-like structure fabricated using silicon microprocessing techniques. This approach has enabled the fabrication of 3-D silicon photonic lattices active in the infrared. The structures display band gaps centered from 12{micro} down to 1.55{micro}.
Contributing Partner: UNT Libraries Government Documents Department
3-D Target Location from Stereoscopic SAR Images

3-D Target Location from Stereoscopic SAR Images

Date: October 1, 1999
Creator: Doerry, Armin W.
Description: SAR range-Doppler images are inherently 2-dimensional. Targets with a height offset lay over onto offset range and azimuth locations. Just which image locations are laid upon depends on the imaging geometry, including depression angle, squint angle, and target bearing. This is the well known layover phenomenon. Images formed with different aperture geometries will exhibit different layover characteristics. These differences can be exploited to ascertain target height information, in a stereoscopic manner. Depending on the imaging geometries, height accuracy can be on the order of horizontal position accuracies, thereby rivaling the best IFSAR capabilities in fine resolution SAR images. All that is required for this to work are two distinct passes with suitably different geometries from any plain old SAR.
Contributing Partner: UNT Libraries Government Documents Department
5/10-MVA high temperature superconducting power transformer. Progress report for the period May 1998 - June 1999

5/10-MVA high temperature superconducting power transformer. Progress report for the period May 1998 - June 1999

Date: July 28, 1999
Creator: Corporation, Intermagnetics General
Description: No abstract prepared.
Contributing Partner: UNT Libraries Government Documents Department
(6)Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses

(6)Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses

Date: February 8, 1999
Creator: Alam, T.M.; Boyle, T.J.; Brow, R.K. & Conzone, S.
Description: {sup 6}Li and {sup 7}Li solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the local coordination environment of lithium in a series of xLi{sub 2}O {center_dot} (1-x)P{sub 2}O{sub 5} glasses, where 0.05 {le} x {le} 0.55. Both the {sup 6}Li and {sup 7}Li show chemical shift variations with changes in the Li{sub 2}O concentration, but the observed {sup 6}Li NMR chemical shifts closely approximate the true isotropic chemical shift and can provide a measure of the lithium bonding environment. The {sup 6}Li NMR results indicate that in this series of lithium phosphate glasses the Li atoms have an average coordination between four and five. The results for the metaphosphate glass agree with the coordination number and range of chemical shifts observed for crystalline LiPO{sub 3}. An increase in the {sup 6}Li NMR chemical shift with increasing Li{sub 2}O content was observed for the entire concentration range investigated, correlating with increased cross-linking of the phosphate tetrahedral network by O-Li-O bridges. The {sup 6}Li chemical shifts were also observed to vary monotonically through the anomalous glass transition temperature (T{sub g}) minimum. This continuous chemical shift variation shows that abrupt changes in the Li coordination ...
Contributing Partner: UNT Libraries Government Documents Department
The 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

The 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

Date: December 1999
Creator: Pronko, S. G. E. & Baggest, D. S.
Description: Over the next three years the DIII-D National Fusion Facility at General Atomics will upgrade its electron cyclotron heating (ECH) capability from the present 3 MW at 110 GHz to 10 MW of injected microwave power. There will be ten gyrotron tubes supplied by five 8.4 MW modulator/regulator (M/R) power systems. The project has gained considerable leverage from the acquisition of surplus hardware from the MFTF program that was conducted at LLNL in the early 1980s. One of these systems had been refurbished and converted for use as an ECH power supply earlier. The experience gained and the lessons learned from operating that system have proved valuable in guiding the engineering of the new systems. This paper provides an overview of the power system design and a report on the present status of the project.
Contributing Partner: UNT Libraries Government Documents Department
15.4% CuIn1-XGaXSe2-Based Photovoltaic Cells from Solution-Based Precursor Films

15.4% CuIn1-XGaXSe2-Based Photovoltaic Cells from Solution-Based Precursor Films

Date: May 25, 1999
Creator: Bhattacharya, R. N.; Batchelor, W.; Contreras, M. A.; Noufi, R. N. (National Renewable Energy Laboratory); Hiltner, J. F. & Sites, J. R. (Department of Physics, Colorado State University)
Description: We have fabricated 15.4%- and 12.4%-efficient CuIn1-XGaXSe2 (CIGS)-based photovoltaic devices from solution-based electrodeposition (ED) and electroless-deposition (EL) precursors. As-deposited precursors are Cu-rich CIGS. Additional In, Ga, and Se are added to the ED and EL precursor films by physical vapor deposition (PVD) to adjust the final film composition to CuIn1-XGaXSe2. The ED and EL device parameters are compared with those of a recent world record, an 18.8%-efficient PVD device. The tools used for comparison are current voltage, capacitance voltage, and spectral response characteristics.
Contributing Partner: UNT Libraries Government Documents Department
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