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A low power ultra-fast current transient measuring device.

Description: We have studied the feasibility of an innovative device to sample 1ns low-power single current transients with a time resolution better than 10 ps. The new concept explored here is to close photoconductive semiconductor switches (PCSS) with a Laser for a period of 10 ps. The PCSSs are in a series along a Transmission Line (TL). The transient propagates along the TL allowing one to carry out a spatially resolved sampling of charge at a fixed time instead of the usual timesampling of the current.… more
Date: October 1, 2004
Creator: Doyle, Barney Lee; Rossi, Paolo; Armendariz, Marcelino G.; Sullivan, John Patrick; Foltynowicz, Robert J. & Zutavern, Fred J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effects of radiation on laser diodes.

Description: The effects of ionizing and neutron radiation on the characteristics and performance of laser diodes are reviewed, and the formation mechanisms for nonradiative recombination centers, the primary type of radiation damage in laser diodes, are discussed. Additional topics include the detrimental effects of aluminum in the active (lasing) volume, the transient effects of high-dose-rate pulses of ionizing radiation, and a summary of ways to improve the radiation hardness of laser diodes. Radiation … more
Date: September 1, 2004
Creator: Phifer, Carol Celeste
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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In-situ Diffraction Studies of Shock Compressed Single-Crystal Iron

Description: The technique of in-situ wide angle diffraction has been used to study materials such as Si and Cu. We have extended our studies of shocked single crystal materials to include Fe (001) that is shock compressed by direct laser irradiation using the OMEGA and Janus lasers. A series of experiments was conducted in Fe at pressures above the Hugoniot Elastic Limit. Transient x-ray was used to record the response of multiple lattice planes simultaneously. This technique of wide-angle diffraction prov… more
Date: July 16, 2004
Creator: Kalantar, D H; Colvin, J D; Eggert, J; Lorenzana, H; Stolken, J; Hawreliak, J et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Improved Energy Coupling into the Gain Region of the Ni-Like Pd Transient Collisional X-Ray Laser

Description: We present within this paper a series of experiments, which yield new observations to further our understanding of the transient collisional x-ray laser medium. We use the recently developed technique of picosecond x-ray laser interferometry to probe the plasma conditions in which the x-ray laser is generated and propagates. This yields two dimensional electron density maps of the plasma taken at different times relative to the peak of the 600ps plasma-forming beam. In another experimental camp… more
Date: October 5, 2004
Creator: Smith, R.; Dunn, J.; Filevich, J.; Moon, S.; Nilsen, J.; Keenan, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Optical Propagation Modeling for the National Ignition Facility

Description: Optical propagation modeling of the National Ignition Facility has been utilized extensively from conceptual design several years ago through to early operations today. In practice we routinely (for every shot) model beam propagation starting from the waveform generator through to the target. This includes the regenerative amplifier, the 4-pass rod amplifier, and the large slab amplifiers. Such models have been improved over time to include details such as distances between components, gain pro… more
Date: January 12, 2004
Creator: Williams, W. H.; Auerbach, J. M.; Henesian, M. A.; Jancaitis, K. S.; Manes, K. R.; Mehta, N. C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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ACME algorithms for contact in a multiphysics environment API version 2.2.

Description: An effort is underway at Sandia National Laboratories to develop a library of algorithms to search for potential interactions between surfaces represented by analytic and discretized topological entities. This effort is also developing algorithms to determine forces due to these interactions for transient dynamics applications. This document describes the Application Programming Interface (API) for the ACME (Algorithms for Contact in a Multiphysics Environment) library.
Date: July 1, 2004
Creator: Heinstein, Martin Wilhelm; Glass, Micheal W.; Gullerud, Arne S.; Brown, Kevin H.; Voth, Thomas Eugene & Jones, Reese E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Modeling an RF Cold Crucible Induction Heated Melter with Subsidence

Description: A method to reduce radioactive waste volume that includes melting glass in a cold crucible radio frequency induction heated melter has been investigated numerically. The purpose of the study is to correlate the numerical investigation with an experimental apparatus that in the above mentioned melter. Unique to this model is the subsidence of the glass as it changes from a powder to molten glass and drastically changes density. A model has been created that couples the magnetic vector potential … more
Date: July 1, 2004
Creator: Hawkes, Grant L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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OECD/NEA Data Bank Scientific and Intergral Experiments Databases in Support of Knowledge Preservation and Transfer

Description: The OECD/Nuclear Energy Data Bank was established by its member countries as an institution to allow effective sharing of knowledge and its basic underlying information and data in key areas of nuclear science and technology. The activities as regards preserving and transferring knowledge consist of the: — Acquisition of basic nuclear data, computer codes and experimental system data needed over a wide range of nuclear and radiation applications. — Independent verification and validation of the… more
Date: September 1, 2004
Creator: Briggs, J. B.; Sartori, E.; Gado, J.; Hasegawa, A.; D'hondt, P.; Kodeli, I. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Vadose Zone Contaminant Fate and Transport Analysis for the 216-B-26 Trench

Description: The BC Cribs and Trenches, part of the 200 TW 1 OU waste sites, received about 30 Mgal of scavenged tank waste, with possibly the largest inventory of 99Tc ever disposed to the soil at Hanford and site remediation is being accelerated. The purpose of this work was to develop a conceptual model for contaminant fate and transport at the 216-B-26 Trench site to support identification and development and evaluation of remediation alternatives. Large concentrations of 99Tc high above the water table… more
Date: October 14, 2004
Creator: Ward, Andy L.; Gee, Glendon W.; Zhang, Z. F. & Keller, Jason M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Plasma conditions for improved energy coupling into the gain region of the Ni-like Pd transient collisional x-ray laser

Description: We have directly probed the plasma conditions in which the Ni-like Pd transient collisional x-ray laser is generated and propagates by measuring the near-field image and by utilizing picosecond resolution soft x-ray laser interferometry of the preformed Pd plasma gain medium. The electron density and gain region of the plasma have been determined experimentally and are found to be in good agreement with simulations. We observe a strong dependence of the laser pump-gain medium coupling on the la… more
Date: October 4, 2004
Creator: Smith, R. F.; Dunn, J.; Filevich, J.; Moon, S.; Nilsen, J.; Keenan, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CHF Enhancement by Vessel Coating for External Reactor Vessel Cooling

Description: In-vessel retention (IVR) is a key severe accident management (SAM) strategy that has been adopted by some operating nuclear power plants and advanced light water reactors (ALWRs). One viable means for IVR is the method of external reactor vessel cooling (ERVC) by flooding of the reactor cavity during a severe accident. As part of a joint Korean – United States International Nuclear Energy Research Initiative (K-INERI), an experimental study has been conducted to investigate the viability of us… more
Date: June 1, 2004
Creator: Cheung, Fan-Bill & Rempe, Joy L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Field-Scale In Situ Measurements of Vadose Zone Flow and Transport Using Multiple Tracers at INEEL Vadose Zone Research Park (VZRP)

Description: This study is aimed at obtaining a better understanding of vadose zone flow and transport processes at the field scale and establishing defensible links between laboratory- and field-derived transport parameters for conservative and reactive elements in the vadose zone. The study site (Vadose Zone Research Park [VZRP] at INEEL) provides a three dimensional instrumentation array strategically surrounding a new infiltration pond slated for initial use in the upcoming year, and the Big Lost River,… more
Date: December 1, 2004
Creator: Asmerom, Yemane
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Extensions to SCDAP/RELAP5/ATHENA for Analysis of HTGRs and SCWRs

Description: The SCDAP/RELAP5/ATHENA code was extended to enable the code to perform transient analyses of High Temperature Gas Reactors (HTGRs). Preliminary results indicate that post-shutdown decay heat can be adequately removed from HTGRs by natural circulation of atmospheric air.
Date: April 1, 2004
Creator: Harvego, E. A. & Siefken, L. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Modeling the Thermal Mechanical Behavior of a 300 K Vacuum Vesselthat is Cooled by Liquid Hydrogen in Film Boiling

Description: This report discusses the results from the rupture of a thin window that is part of a 20-liter liquid hydrogen vessel. This rupture will spill liquid hydrogen onto the walls and bottom of a 300 K cylindrical vacuum vessel. The spilled hydrogen goes into film boiling, which removes the thermal energy from the vacuum vessel wall. This report analyzes the transient heat transfer in the vessel and calculates the thermal deflection and stress that will result from the boiling liquid in contact with … more
Date: May 7, 2004
Creator: Yang, S.Q.; Green, M.A. & Lau, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Multi-dimensional multi-species modeling of transient electrodeposition in LIGA microfabrication.

Description: This report documents the efforts and accomplishments of the LIGA electrodeposition modeling project which was headed by the ASCI Materials and Physics Modeling Program. A multi-dimensional framework based on GOMA was developed for modeling time-dependent diffusion and migration of multiple charged species in a dilute electrolyte solution with reduction electro-chemical reactions on moving deposition surfaces. By combining the species mass conservation equations with the electroneutrality const… more
Date: June 1, 2004
Creator: Evans, Gregory Herbert (Sandia National Laboratories, Livermore, CA) & Chen, Ken Shuang
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Validated modeling of distributed energy resources at distribution voltages : LDRD project 38672.

Description: A significant barrier to the deployment of distributed energy resources (DER) onto the power grid is uncertainty on the part of utility engineers regarding impacts of DER on their distribution systems. Because of the many possible combinations of DER and local power system characteristics, these impacts can most effectively be studied by computer simulation. The goal of this LDRD project was to develop and experimentally validate models of transient and steady state source behavior for incorpor… more
Date: March 1, 2004
Creator: Ralph, Mark E. & Ginn, Jerry W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermophysical Properties of Heat Resistant Shielding Material

Description: This project was aimed at determining thermal conductivity, specific heat and thermal expansion of a heat resistant shielding material for neutron absorption applications. These data are critical in predicting the structural integrity of the shielding under thermal cycling and mechanical load. The measurements of thermal conductivity and specific heat were conducted in air at five different temperatures (-31 F, 73.4 F, 140 F, 212 F and 302 F). The transient plane source (TPS) method was used in… more
Date: December 15, 2004
Creator: Porter, W.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Progress in the Peeling-Ballooning Model of Elms: Toroidal Rotation and 3d Nonlinear Dynamics

Description: Understanding the physics of the H-Mode pedestal and edge localized modes (ELMs) is very important to next-step fusion devices for two primary reasons: (1) The pressure at the top of the edge barrier (''pedestal height'') strongly impacts global confinement and fusion performance, and (2) large ELMs lead to localized transient heat loads on material surfaces that may constrain component lifetimes. The development of the peeling-ballooning model has shed light on these issues by positing a mecha… more
Date: June 1, 2004
Creator: Snyder, P. B.; Wilson, H. R.; Xu, X. Q. & Webster, A. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

New advances in three dimensional transient electromagnetic inversion

Description: Inversion of transient electromagnetic (TEM) data sets to image the subsurface three-dimensional (3-D) electrical conductivity and magnetic permeability properties can be done directly in the time domain. The technique, first introduced by Wang et al. (1994) for causal and diffusive electromagnetic fields and subsequently implemented by Zhdanov and Portniaguine (1997) in the framework of iterative migration, is based upon imaging methods originally developed for seismic wavefields (Claerbout, 1… more
Date: June 16, 2004
Creator: Newman, Gregory A. & Commer, Michael
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Proposed Strategies for DWPF Melter Off-Gas Surge Control

Description: Off-gas surging is inherent to the operation of slurry-fed melters. Although the melter design and the feed chemistry are both known to significantly affect off-gas surging, the frequency and intensity of surges are in essence unpredictable. In typical off-gas surges, both condensable and non condensable flows spike simultaneously. Condensable or steam surges have been observed to occur as the boiling water layer occasionally falls into the crevices of the cold cap or flows over the edges of th… more
Date: June 1, 2004
Creator: CHOI, ALEXANDERS.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

CST Suspension Analysis for Slurry Pumps of Tank 40

Description: Tank 40 simulation models with four submersible slurry pumps available for the CST suspension operations have been developed to provide operational guidance of slurry pumps for an efficient sludge removal. A series of the modeling calculations have been performed for key operational parameters such as pump operation mode, number of operating pumps, and to provide a recommendation for CST suspension and mixing operations in Tank 40. Reference design and operating conditions shown in Table 1 were… more
Date: April 1, 2004
Creator: LEE, SIY.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Investigation of Pore Scale Processes That Affect Soil Vapor Extraction

Description: Dense nonaqueous phase liquid (DNAPL) contamination in the vadose zone is a significant problem at Department of Energy sites. Soil vapor extraction (SVE) is commonly used to remediate DNAPLs from the vadose zone. In most cases, a period of high recovery has been followed by a sustained period of low recovery. This behavior has been attributed to multiple processes including slow interphase mass transfer, retarded vapor phase transport, and diffusion from unswept zones of low permeability. Prio… more
Date: June 24, 2004
Creator: Valocchi, Albert J.; Werth, Charles J. & Webb, Andrew G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-transform sum-frequency vibrational spectroscopy

Description: The high temporal resolution and broad bandwidth of a femtosecond laser system are exploited in a pair of nonlinear optical studies of surfaces. The dephasing dynamics of resonances associated with the adatom dangling bonds of the Si(111)7 x 7 surface are explored by transient second-harmonic hole burning, a process that can be described as a fourth-order nonlinear optical process. Spectral holes produced by a 100 fs pump pulse at about 800 nm are probed by the second harmonic signal of a 100 f… more
Date: November 24, 2004
Creator: McGuire, John Andrew
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers

Description: Integrity monitoring and flaw diagnostics of flat beams and tubular structures was investigated in this research task using guided acoustic signals. A piezo-sensor suite was deployed to activate and collect Lamb wave signals that propagate along metallic specimens. The dispersion curves of Lamb waves along plate and tubular structures are generated through numerical analysis. Several advanced techniques were explored to extract representative features from acoustic time series. Among them, the … more
Date: September 27, 2004
Creator: Upadhyaya, Belle R. & Hines, J. Wesley
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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