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Qualification of Safety-Related Software in Nuclear Power Plants

Description: Digital instrumentation and control systems have the potential of offering significant benefits over traditional analog systems in Nuclear Power Plant safety systems, but there are also significant difficulties in qualifying digital systems to the satisfaction of regulators. Digital systems differ in fundamental ways from analog systems. New methods for safety qualification, which take these differences into account, would ease the regulatory cost and promote use of digital systems. This paper … more
Date: June 13, 2000
Creator: Johnson, G L
Partner: UNT Libraries Government Documents Department
open access

Wong's equations and the small x effective action in QCD

Description: We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x.
Date: July 13, 2000
Creator: Jalilian-Marian, Jamal; Jeon, Sangyong & Venugopalan, Raju
Partner: UNT Libraries Government Documents Department
open access

Using Arrested Solid-Solid Multiphase Reactions in Geological Materials to Deduce the Rate of Crustal Uplift

Description: The history geological terrains experience can be traced as a series of temperature and pressure changes. Each change drives the system toward a new state of thermodynamic equilibrium. The resultant overprinted rock fabrics, textures and chemical heterogeneities can be difficult to interpret. However, if carefully chosen, features from the scale of kilometers to nanometers can be used to reconstruct the history of mountain systems. Uplift of the Sri Lankan Central Highlands was rapid enough to … more
Date: March 13, 2000
Creator: Glassley, W.E. & Meike, A.
Partner: UNT Libraries Government Documents Department
open access

The AERI/GOES Retrievals Versus Radiosondes for Driving SCMs

Description: Single-Column Models (SCMs) require observations to provide suitable initial and boundary conditions. To meet this need, the Atmospheric Radiation Measurement (ARM) program conducts Intensive Observing Periods (IOPs) to provide 3-hourly radiosondes and other observations. However, such high-frequency sonde launches can be expensive. Therefore, the ARM program can only support a couple IOPs each year with each one lasting 2-4 weeks. In order to reduce the need for high-frequency sonde launches a… more
Date: July 13, 2000
Creator: Xie, S. C.; Cederwell, R. T.; Yio, J. J.; Feltz, W. F.; Turner, D. D. & Zhang, M. H.
Partner: UNT Libraries Government Documents Department
open access

Diagnosing Plasma Gradients Using Spectral Line Shapes

Description: The development of a set of stable implosions using indirectly driven plastic microspheres with argon (0.1 atm) doped deuterium (50 atm) has provided a unique source for testing the plasma spectroscopy of the high energy density imploded core. The core reaches electron densities of > 10{sup 24} cm{sup -3} with temperatures of {approx} 1 keV and has been shown to be reproducible on a shot to shot basis. Moreover, it has been shown that not only the peak temperature and density are consistent,… more
Date: November 13, 2000
Creator: Back, C. A.; Golovkin, I.; Mancini, R.; Missalla, T.; Landen, O. L.; Lee, R. W. et al.
Partner: UNT Libraries Government Documents Department
open access

Multigrid algorithms for solving the linear Boltzmann equation using first-order system least-squares finite element methods

Description: Solving the linear Boltzmann equation in neutron scattering phenomena presents many challenges to standard numerical schemes in computational physics. For an SN discretization, the so-called ray effects pollute the numerical solution. This pollution can be viewed mathematically as ''contamination'' from a poorly chosen approximating basis set for the angle component of the discretization-i.e., collocation in angle is equivalent to discretization with delta basis functions, which form a poor app… more
Date: December 13, 2000
Creator: Chang, B. & Lee, B.
Partner: UNT Libraries Government Documents Department
open access

Prompt GRB optical follow-up experiments

Description: Gamma Ray Bursts (GRBs) are brief, randomly located, releases of gamma-ray energy from unknown celestial sources that occur almost daily. The study of GRBs has undergone a revolution in the past three years due to an international effort of follow-up observations of coordinates provided by Beppo/SAX and IPN GRB. These follow-up observations have shown that GRBs are at cosmological distances and interact with surrounding material as described by the fireball model. However, prompt optical counte… more
Date: November 13, 2000
Creator: Park, H. S.; Williams, G.; Ables, E.; Band, D.; Barthelmy, S.; Bionta, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Numerical simulation of damage and fracture in concrete from shaped charge jets

Description: This paper addresses numerical simulation of damage and fracture in concrete from the impact and penetration of shaped charge jets. We have modeled the jet penetration process with CALE, a two dimensional arbitrary Lagrange Eulerian hydrocode. We have looked at several constitutive models ranging from simple pressure dependent yield to more complex deviatoric models that include the effects of dilatency. Evaluation of the concrete material models is based on comparison to experimental results o… more
Date: September 13, 2000
Creator: Murphy, M J; Baum, D W; Clark, D B; McGuire, E M & Simonson, S C
Partner: UNT Libraries Government Documents Department
open access

PCMDI analysis of candidate atmospheric models for CCSM

Description: This report is intended to give a summary analysis of the candidate model configurations under consideration by NCAR for the atmospheric component of next version of the Community Climate System Model (CCSM). Intercomparison results are presented for each of the models available prior to the Atmospheric Model Working Group (AMWG) meeting, December 12-14, 2000. We present four types of figures in this report. The traditional methods of viewing zonal mean surface fields, latitude-longitude maps a… more
Date: December 13, 2000
Creator: Wehner, M. F.; Taylor, K.; Doutriaux, C.; AchutaRao, K.; Gleckler, P.; Hnilo, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Optimizing Data Recording for the NIF Core Diagnostic X-ray Streak Camera

Description: The x-ray streak camera is an important instrument for recording a continuous time history of x-ray emitted from laser target experiments. X-ray streak cameras were used to diagnose experiments in inertially confined fusion and high energy density sciences on the Nova laser. These streak cameras are now used for similar experiments conducted at the OMEGA laser facility, and cameras of this type will be used for experiments on the National Ignition Facility (NIF). The Nova x-ray streak cameras (… more
Date: June 13, 2000
Creator: Kalantar, D H; Bell, P M; Perry, T S; Sewall, N; Diamond, C & Piston, K
Partner: UNT Libraries Government Documents Department
open access

Preliminary safety assessment for an IFE target fabrication facility

Description: We estimate possible ranges of tritium inventories for an inertial fusion energy (IFE) target fabrication facility producing various types of targets and using various production technologies. Target fill is the key subtask in determining the overall tritium inventory for the plant. By segmenting the inventory into multiple, parallel production lines--each with its own fill canister--and including an expansion tank to limit releases, we are able to ensure that a target fabrication facility woul… more
Date: October 13, 2000
Creator: Latkowski, J F; Reyes, S; Besenbruch, G E & Goodin, D T
Partner: UNT Libraries Government Documents Department
open access

Statistical error in particle simulations of low mach number flows

Description: We present predictions for the statistical error due to finite sampling in the presence of thermal fluctuations in molecular simulation algorithms. The expressions are derived using equilibrium statistical mechanics. The results show that the number of samples needed to adequately resolve the flowfield scales as the inverse square of the Mach number. Agreement of the theory with direct Monte Carlo simulations shows that the use of equilibrium theory is justified.
Date: November 13, 2000
Creator: Hadjiconstantinou, N G & Garcia, A L
Partner: UNT Libraries Government Documents Department
open access

Development and Characterization of a Single Line of Sight Framing Camera

Description: We present initial characterization data from a new single line of sight (SLOS) x-ray framing camera. The instrument uses an image dissecting structure inside an electron optic tube to produce up to four simultaneous DC images from a single image incident on the cathode and a microchannel plate based device to provide the temporal gating of those images. A series of gated images have been obtained using a short pulse UV laser source, and the spatial resolution of those images is compared to tho… more
Date: June 13, 2000
Creator: Bradley, D K; Bell, P M; Dymoke-Bradshaw, A K L; Hares, J D; Bahr, R E & Smalyuk, V A
Partner: UNT Libraries Government Documents Department
open access

Cloud-Resolving Model Intercomparison with the ARM Summer 1997 IOP Data

Description: The Atmospheric Radiation Measurement (ARM) Program's Single Column Model (SCM) working group conducted its intercomparison study of midlatitude summertime continental convection using the July 1995 Intensive Operational Period (IOP) data set (Ghan et al. 2000). Only one cloud-resolving model (CRM) participated in the study. On the other hand, several CRMs participated in the GEWEX (Global Energy and Water-cycle Experiment) Cloud System Study (GCSS) Working Group 4's intercomparison study of tr… more
Date: March 13, 2000
Creator: Xu, K. M.; Johnson, D. E.; Tao, W. K.; Krueger, S. K.; Khairoutdinov, M.; Randall, D. A. et al.
Partner: UNT Libraries Government Documents Department
open access

American National Standard ANSI/ANS-8.12-1987: Criticality Control of Plutonium-Uranium Mixtures

Description: American National Standard ANSI/ANS-8.12-1987 (Ref. 1) was approved for use on September 11, 1987, The history of the development of the standard is discussed in Ref. 2. The first version of this standard, which included subcritical limits only on homogeneous plutonium-uranium fuel mixtures, was approved July 17, 1978. The current version was revised to add limits on heterogeneous systems (Ref., 3). This paper provides additional information on the limits presented in the standard.
Date: June 13, 2000
Creator: Shaeffer, M. K. & Keeton, S. C.
Partner: UNT Libraries Government Documents Department
open access

Interfacial Dislocations and Deformation Twinning in Fully Lamellar TiAl

Description: Deformation twinning, which takes place abnormally within lamellar TiAl subjected to creep deformation at strain rates as low as 10{sup -7}, has been found to be intimately related to the motion, pileup and dissociation of interfacial (Shockley partial) dislocations. In this study, results of in-situ TEM observations are presented to verify the motion and pileup of interfacial dislocations. Since the interfacial (Shockley partial) dislocations are energetically unfavorable to undergo cross-slip… more
Date: July 13, 2000
Creator: Hsiung, L. M.; Choi, B. W. & Nieh, T. G.
Partner: UNT Libraries Government Documents Department
open access

Visible imaging of edge turbulence in NSTX

Description: Edge plasma turbulence in tokamaks and stellarators is believed to cause the radical heat and particle flux across the separatrix and into the scrape-off-layers of these devices. This paper describes initial measurements of 2-D space-time structure of the edge density turbulence made using a visible imaging diagnostic in the National Spherical Torus Experiment (NSTX). The structure of the edge turbulence is most clearly visible using a method of gas puff imaging to locally illuminate the edge d… more
Date: June 13, 2000
Creator: Zweben, S.; Maqueda, R.; Hill, K.; Johnson, D. & al, et
Partner: UNT Libraries Government Documents Department
open access

Determining equivalent damage loading for full-scale wind turbine blade fatigue tests

Description: This paper describes a simplified method for converting wind turbine rotor design loads into equivalent-damage, constant-amplitude loads and load ratios for both flap and lead-lag directions. It is an iterative method that was developed at the National Renewable Energy Laboratory (NREL) using Palmgren-Miner's linear damage principles. The general method is unique because it does not presume that any information about the materials or blade structural properties is precisely known. According to … more
Date: March 13, 2000
Creator: Freebury, G. & Musial, W.
Partner: UNT Libraries Government Documents Department
open access

Investigation of vessel exterior air cooling for a HLMC reactor

Description: The Secure Transportable Autonomous Reactor (STAR) concept under development at Argonne National Laboratory provides a small (300 MWt) reactor module for steam supply that incorporates design features to attain proliferation resistance, heightened passive safety, and improved cost competitiveness through extreme simplification. Examples are the achievement of 100%+ natural circulation heat removal from the low power density/low pressure drop ultra-long lifetime core and utilization of lead-bism… more
Date: January 13, 2000
Creator: Sienicki, J. J. & Spencer, B. W.
Partner: UNT Libraries Government Documents Department
open access

Magnetoconductance of Independently Tunable Tunnel-Coupled Double Quantum Wires

Description: The authors report on their recent experimental studies of vertically-coupled quantum point contacts subject to in-plane magnetic fields. Using a novel flip-chip technique, mutually aligned split gates on both sides of a sub micron thick double quantum well heterostructure define a closely-coupled pair of ballistic one-dimensional (1D) constrictions. They observe quantized conductance steps due to each quantum well and demonstrate independent control of each ID constriction width. In addition, … more
Date: July 13, 2000
Creator: Blount, Mark A.; Moon, J. S.; Simmons, Jerry A.; Lyo, Sungkwun K.; Wendt, Joel R. & Reno, John L.
Partner: UNT Libraries Government Documents Department
open access

Applied environmental technology development at the Savannah River Site: A retrospective on the last half of the 20th century

Description: Fifty years ago, the Savannah River Site (SRS) was built to produce nuclear materials. These operations impacted air, soil, groundwater, ecology and the local environment. Throughout its history, SRS has addressed these contamination issues directly and has maintained a strong commitment to environmental stewardship. The site boasts many environmental firsts. Notably, SRS was the first major DOE facility to perform a baseline ecological assessment. This pioneering effort, by Ruth Patrick and th… more
Date: March 13, 2000
Creator: Looney, B. B.
Partner: UNT Libraries Government Documents Department
open access

RF cogging in the FNAL Booster Accelerator

Description: The Fermilab Booster operates at a Radio Frequency (RF) harmonic number of 84 with beam in all buckets. One or two bunches of beam are systematically lost in the 8 GeV extraction process as beam is swept across a magnetic septum during the extraction kicker rise time. The prompt radiation and component activation resulting from this localized high energy beam loss become serious concerns as Booster beam throughput must be increased more than tenfold to meet the requirements of RUN II, NUMI, and… more
Date: June 13, 2000
Creator: Webber, William A. Pellico and Robert C.
Partner: UNT Libraries Government Documents Department
open access

Accelerating technology transfer from federal laboratories to the private sector by industrial R and D collaborations - A new business model

Description: Many important products and technologies were developed in federal laboratories and were driven initially by national needs and for federal applications. For example, the clean room technology that enhanced the growth of the semiconductor industry was developed at Sandia National Laboratories (SNL) decades ago. Similarly, advances in micro-electro-mechanical-systems (MEMS)--an important set of process technologies vital for product miniaturization--are occurring at SNL. Each of the more than 50… more
Date: April 13, 2000
Creator: Lombana, Cesar A.; Romig, Alton D.; Linton, Jonathan D. & Martinez, J. Leonard
Partner: UNT Libraries Government Documents Department
open access

Power for peace, prosperity, and the environment

Description: The remarkable prosperity and standard of living enjoyed in the US is in large part linked to the use of energy. While high-energy use brings many benefits, it also causes environmental degradation. In the last decade, the potentially devastating effects of degradation of greenhouse gases have received worldwide attention. The tradeoff between sustaining a healthy environment and sustaining a healthy economy is a major challenge of the 21st century. In this paper, the authors explore some of th… more
Date: April 13, 2000
Creator: Eagan, Robert J.; Baker, Arnold B. & Sanders, Thomas L.
Partner: UNT Libraries Government Documents Department
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