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open access

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

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 … more
Date: June 17, 1999
Creator: Bartel, Timothy J.; Economou, Demetre & Johannes, Justine E.
open access

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

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 … more
Date: November 29, 1999
Creator: Larson, B. C.; tamura, N.; Chung, J.-S.; Ice, G. E.; Budai, J. D.; Tischler, J. Z. et al.
open access

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

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 t… more
Date: July 8, 1999
Creator: Fleming, J.G. & Lin, Shawn-Yu
open access

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

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 … more
Date: February 8, 1999
Creator: Alam, T.M.; Boyle, T.J.; Brow, R.K. & Conzone, S.
open access

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

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 ref… more
Date: December 1999
Creator: Pronko, S. G. E. & Baggest, D. S.
open access

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

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 … more
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)
open access

A 100-kV, 2-kA, 2.5-{micro}S Pulser for Developing and Calibrating Long-Pulse Diagnostics

Description: The development of voltage and current probes for measuring an electron beam's current and position associated with several microsecond-long pulses from advanced Linear Induction Accelerators requires a precision pulser that can deliver both high voltages and high currents to a diagnostics Test Line. Seven-stage, type-E PFNs have been utilized in both a transformer and 4-stage Marx (plus/minus) configuration. The resulting 50-ohm pulser delivers to the Test Line a repeatable 100 kV, ca. 2 {micr… more
Date: June 27, 1999
Creator: Carlson, R.L.
open access

The 110 GHz Gyrotron System on DIII-D: Gyrotron Tests and Physics Results

Description: The DIII-D tokamak has installed a system with three gyrotrons at the 1 MW level operating at 110 GHz. Physics experiments on electron cyclotron current drive, heating, and transport have been performed. Good efficiency has been achieved both for on-axis and off-axis current drive with relevance for control of the current density profile leading to advanced regimes of tokamak operation, although there is a difference between off-axis ECCD efficiency inside and outside the magnetic axis. Heating… more
Date: December 1, 1999
Creator: Lohr, J.; Calahan, P.; Callis, R. W.; Chu, T. S.; deGrassie, J. S.; Gorelov, I. et al.
open access

(129)Xe NMR of Mesoporous Silicas

Description: The porosities of three mesoporous silica materials were characterized with {sup 129}Xe NMR spectroscopy. The materials were synthesized by a sol-gel process with r = 0, 25, and 70% methanol by weight in an aqueous cetyltrimethylammonium bromide solution. Temperature dependent chemical shifts and spin lattice relaxation times reveal that xenon does not penetrate the pores of the largely disordered (r= 70%) silica. For both r = 0 and 25%, temperature dependent resonances corresponding to physiso… more
Date: April 23, 1999
Creator: Anderson, M.T.; Asink, R.A.; Kneller, J.M. & Pietrass, T.
open access

11th International Conference of Radiation Research

Description: Topics discussed in the conference included the following: Radiation Physics, Radiation Chemistry and modelling--Radiation physics and dosimetry; Electron transfer in biological media; Radiation chemistry; Biophysical and biochemical modelling; Mechanisms of DNA damage; Assays of DNA damage; Energy deposition in micro volumes; Photo-effects; Special techniques and technologies; Oxidative damage. Molecular and cellular effects-- Photobiology; Cell cycle effects; DNA damage: Strand breaks; DNA da… more
Date: July 18, 1999
open access

12th Annual ALS Users' Association Meeting

Description: Science took the front seat as 219 Advanced Light Source (ALS) users and staff gathered on Monday and Tuesday, October 18 and 19 for the twelfth annual users' meeting. The bulk of the meeting was dedicated to reports on science at the ALS. Packed into two busy days were 31 invited oral presentations and 80 submitted poster presentations, as well as time to visit 24 vendor booths. The oral sessions were dedicated to environmental science, chemical dynamics, biosciences, magnetic materials, and a… more
Date: December 17, 1999
Creator: Robinson, Arthur L.
open access

[12th International workshop on Inelastic Ion-Surface Collisions]

Description: The twelfth international workshop on inelastic ion surface collisions was held at the Bahia Mar Resort and Conference Center on South Padre Island, Texas (USA) from January 24-29, 1999. The workshop brought together most of the leading researchers from around the world to focus on both the theoretical and experimental aspects of particle - surface interactions and related topics.
Date: October 15, 1999
Creator: Rabalais, J. W. & Nordlander, P.
open access

14C dating of bone using (gamma) Carboxyglutamic Acid and Carboxyglycine (Aminomalonate)

Description: Radiocarbon determinations have been obtained on {gamma}-carboxyglutamic acid [Gla] and {alpha}-carboxyglycine (aminomalonate) [Am] as well as acid- and base-hydrolyzed total amino acids isolated from a series of fossil bones. As far as they are aware, Am has not been reported previously in fossil bone and neither Gla nor Am {sup 14}C values have been measured previously. Interest in Gla, an amino acid found in the non-collagen proteins osteocalcin and matrix Gla-protein (MGP), proceeds from th… more
Date: April 27, 1999
Creator: Southon, J R; Burky, R T; Kirner, D L; Taylor, R E & Hare, P E
open access

1999 Gordon Research Conference on Mammalian DNA Repair. Final Progress Report

Description: This Conference will examine DNA repair as the key component in genomic surveillance that is so crucial to the overall integrity and function of mammalian cells. Recent discoveries have catapulted the field of DNA repair into a pivotal position for fundamental investigations into oncology, aging, environmental health, and developmental biology. We hope to highlight the most promising and exciting avenues of research in robust discussions at this conference. This Mammalian DNA Repair Gordon Conf… more
Date: February 12, 1999
open access

1st-Principles Step- and Kink-Formation Energies on Cu(111)

Description: In rough agreement with experimental values derived from Cu island shapes vs. temperature, ab-initio calculations yield formation energies of 0.27 and 0.26 eV/ step-edge-atom for (100)- and (111)-micro facet steps on Cu(lll), and 0.09 and 0.12 eV per kink in those steps. Comparison to ab-initio results for Al and Pt shows that as a rule, the average formation energy of straight steps on a close-packed metal surface equals -7% of the metal's cohesive energy.
Date: May 26, 1999
Creator: Feibelman, Peter J.
open access

2nd Workshop on Satellites for Solar Energy Assessments

Description: A Collection of Presentations on new techniques for developing climatological estimates of the solar resource at all locations on earth at a resolution of 100km, and of developing estimates at half-hour intervals at resolutions of 10 km or less in specific locations.
Date: June 28, 1999
Creator: Renne, D.
open access

3D finite-difference frequency-domain code for electromagnetic induction tomography

Description: The effect of shrapnel on target chamber components and experiments at large lasers such as the National Ignition Facility at LLNL and the Megajoule Laser at CESTA in France is an important issue in fielding targets and exposure samples. Modeling calculations are likely to be an important component of this effort. Some work in this area has been performed by French workers, who are collaborating with the LLNL on many issues relating to target chamber, experiment-component, and diagnostics survi… more
Date: July 28, 1999
Creator: Berryman, J. G.; Champagne, N. J., II & Buettner, H. M.
open access

3D Imaging of Porous Media Using Laser Scanning Confocal Microscopy with Application to Microscale Transport Processes

Description: We present advances in the application of laser scanning confocal microscopy (LSCM) to image, reconstruct, and characterize statistically the microgeometry of porous geologic and engineering materials. We discuss technical and practical aspects of this imaging technique, including both its advantages and limitations. Confocal imaging can be used to optically section a material, with sub-micron resolution possible in the lateral and axial planes. The resultant volumetric image data, consisting o… more
Date: February 10, 1999
Creator: Fredrich, J.T.
open access

3D modeling of metallic grain growth

Description: This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve b… more
Date: June 1, 1999
Creator: George, D.; Carlson, N.; Gammel, J.T. & Kuprat, A.
open access

3D unstructured mesh ALE hydrodynamics with the upwind discontinuous galerkin method

Description: The authors describe a numerical scheme to solve 3D Arbitrary Lagrangian-Eulerian (ALE) hydrodynamics on an unstructured mesh using a discontinuous Galerkin method (DGM) and an explicit Runge-Kutta time discretization. Upwinding is achieved through Roe's linearized Riemann solver with the Harten-Hyman entropy fix. For stabilization, a 3D quadratic programming generalization of van Leer's 1D minmod slope limiter is used along with a Lapidus type artificial viscosity. This DGM scheme has been tes… more
Date: May 7, 1999
Creator: Kershaw, D S; Milovich, J L; Prasad, M K; Shaw, M J & Shestakov, A I
open access

3D visualization of port simulation.

Description: Affordable and realistic three dimensional visualization technology can be applied to large scale constructive simulations such as the port simulation model, PORTSIM. These visualization tools enhance the experienced planner's ability to form mental models of how seaport operations will unfold when the simulation model is implemented and executed. They also offer unique opportunities to train new planners not only in the use of the simulation model but on the layout and design of seaports. Simu… more
Date: June 14, 1999
Creator: Horsthemke, W. H.; Macal, C. M. & Nevins, M. R.
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