74 Matching Results

Search Results

Results: 1 - 24 next
open access

Laser Heated High Density Fluids Probed by Coherent Anti-Stokes Raman Spectroscopy

Description: We describe an integrated experimental method of Coherent Antistoke Raman Spectroscopy (CARS), laser-heating and diamond-anvil cell (DAC) technologies probing molecular vibrations of transparent molecular fluids at the pressure-temperature conditions of energetic detonation and Giant planetary interiors. In this method, we use a microfabricated metal toroid to conductively heat a surrounding transparent sample in a DAC, using a CW Nd:YLF laser. The laser is operated at a TEM{sub 01*} mode to ma… more
Date: May 19, 2004
Creator: Baer, B J & Yoo, C
Partner: UNT Libraries Government Documents Department
open access

Clothes washer standards in China -- The problem of water andenergy trade-offs in establishing efficiency standards

Description: Currently the sales of clothes washers in China consist ofseveral general varieties. Some use more energy (with or withoutincluding hot water energy use) and some use more water. Both energy andwater are in short supply in China. This poses the question - how do youtrade off water versus energy in establishing efficiency standards? Thispaper discusses how China dealt with this situation and how itestablished minimum efficiency standards for clothes washers.
Date: May 19, 2004
Creator: Biermayer, Peter J. & Lin, Jiang
Partner: UNT Libraries Government Documents Department
open access

The Development of Detailed Human Factors Engineering Guidelines for Digital Control Room Upgrades.

Description: As part of the Department of Energy and Electric Power Research Institute's hybrid control room project, detailed human factors engineering guidance was developed for designing human-system interfaces that may be affected by introduction of additional digital technology during modernization of nuclear power plants. The guidance addresses several aspects of human-system interaction: information display, interface management, soft controls, alarms, computer-based procedures, computerized operator… more
Date: September 19, 2004
Creator: Brown, W. & O'Hara, J. M.
Partner: UNT Libraries Government Documents Department
open access

Design Aspects of an MSE Diagnostic for ITER

Description: The Motional Stark Effect (MSE) diagnostic is unique in its ability to measure the current profile and will be essential in ITER for detailed analysis of Advanced Tokamak (AT) and other types of discharges. However, design of a MSE diagnostic for ITER presents many unique challenges. Among these is optical analysis for the convoluted optical path, required for effective neutron shielding, that employs several reflective optics arranged to form a labyrinth. The geometry of the diagnostic has bee… more
Date: April 19, 2004
Creator: Casper, T.; Jayakumar, J.; Makowski, M. & Ellis, R.
Partner: UNT Libraries Government Documents Department
open access

Issues Associated With Probabilistic Failure Modeling of Digital Systems

Description: The current U.S. Nuclear Regulatory Commission (NRC) licensing process of instrumentation and control (I&C) systems is based on deterministic requirements, e.g., single failure criteria, and defense in depth and diversity. Probabilistic considerations can be used as supplements to the deterministic process. The National Research Council has recommended development of methods for estimating failure probabilities of digital systems, including commercial off-the-shelf (COTS) equipment, for use… more
Date: September 19, 2004
Creator: Chu, T. L.; Martinez-Guridi,G.; Lehner, J. & Overland, D.
Partner: UNT Libraries Government Documents Department
open access

Atomic Control Of Water Interaction With Biocompatible Surfaces: The Case Of SiC(001)

Description: The interaction of water with Si- and C- terminated {beta}-SiC(001) surfaces was investigated by means of ab initio molecular dynamics simulations. Irrespective of coverage, varied from 1/4 to 1 monolayer, we found that water dissociates on the Si-terminated surface, substantially modifying the clean surface reconstruction, while the C-terminated surface is nonreactive and hydrophobic. Based on our results, we propose that STM images and photoemission experiments may detect specific changes ind… more
Date: July 19, 2004
Creator: Cicero, G; Catellani, A & Galli, G
Partner: UNT Libraries Government Documents Department
open access

Shape Metamorphism Using p-Laplacian Equation

Description: We present a new approach for shape metamorphism, which is a process of gradually changing a source shape (known) through intermediate shapes (unknown) into a target shape (known). The problem, when represented with implicit scalar function, is under-constrained, and regularization is needed. Using the p-Laplacian equation (PLE), we generalize a series of regularization terms based on the gradient of the implicit function, and we show that the present methods lack additional constraints for a m… more
Date: May 19, 2004
Creator: Cong, Ge; Esser, Mehmet; Parvin, Bahram & Bebis, George
Partner: UNT Libraries Government Documents Department
open access

Electron Clouds and Vacuum Pressure Rise in RHIC.

Description: The luminosity in RHIC is limited by vacuum pressure rises, observed with high intensity beams of all species (Au{sup 79+}, d{sup +}, p{sup +}). At injection, the pressure rise could be linked to the existence of electron clouds. In addition, pressure rises in the experimental regions may be caused by electron clouds. They review the existing observations, comparisons with simulations, as well as corrective measures taken and planned.
Date: April 19, 2004
Creator: Fischer, W.; Blaskiewicz, M.; He, P.; Huang, H.; Hseuh, H. C.; Iriso, U. et al.
Partner: UNT Libraries Government Documents Department
open access

Large basis ab initio shell model investigation of 9Be and 11Be

Description: We are presenting the first ab initio structure investigation of the loosely bound {sup 11}Be nucleus, together with a study of the lighter isotope {sup 9}Be. The nuclear structure of these isotopes is particularly interesting due to the appearance of a parity-inverted ground state in {sup 11}Be. Our study is performed in the framework of the ab initio no-core shell model. Results obtained using four different, high-precision two-nucleon interactions, in model spaces up to 9{h_bar}{Omega}, are … more
Date: November 19, 2004
Creator: Forssen, C; Navratil, P; Ormand, W E & Caurier, E
Partner: UNT Libraries Government Documents Department
open access

Long Period Variables in the LMC: Results from MACHO and 2Mass

Description: We use the eight year light curve database from the MACHO (MAssive Compact Halo Objects) project together with infrared colors and magnitudes from 2MASS (the Two Micron All Sky Survey) to identify a sample of 22,000 long period variables in the Large Magellanic Cloud (referred to hereafter as LMC LPVs). A period luminosity diagram of these stars reveals six well defined sequences, in substantial agreement with previous analyses of samples from OGLE (Optical Gravitational Lensing Experiment). In… more
Date: July 19, 2004
Creator: Fraser, O J; Cook, K H; Keller, S C & Hawley, S L
Partner: UNT Libraries Government Documents Department
open access

Dynamic ionization of water under extreme conditions

Description: Raman spectroscopy has been used to study fluid water at approximately 1000 K and 2 to 60 GPa in a laser heated diamond anvil cell. First principles molecular dynamics (MD) simulations have also been employed to simulate water under similar conditions. The experimental Raman intensity of the O-H stretch mode was observed to decrease with pressure, and beyond 50 GPa this mode was no longer visible. At approximately the same pressure we inferred a change in the slope of the melting curve. Consist… more
Date: July 19, 2004
Creator: Goncharov, A F; Goldman, N; Fried, L E; Crowhurst, J C; Kuo, I W; Mundy, C J et al.
Partner: UNT Libraries Government Documents Department
open access

Two-Particle Interferometry of 200 GeV Au+Au Collisions at PHENIX

Description: The PHENIX experiment has measured pion-pion, kaon-kaon, and proton-proton correlations in Au+Au collisions at {radical}S{sub NN} = 200GeV. The correlations are fit to extract radii using both the Bowler Coulomb correction and full calculation of the two-particle wave function. The resulting radii are similar for all three species and decrease with increasing k{sub t} as expected for collective flow. The R{sub out} and R{sub side} radii are approximately equal indicating a short emission durati… more
Date: April 19, 2004
Creator: Heffner, M
Partner: UNT Libraries Government Documents Department
open access

Quantifying human vitamin kinetics using AMS

Description: Tracing vitamin kinetics at physiologic concentrations has been hampered by a lack of quantitative sensitivity for chemically equivalent tracers that could be used safely in healthy people. Instead, elderly or ill volunteers were sought for studies involving pharmacologic doses with radioisotopic labels. These studies fail to be relevant in two ways: vitamins are inherently micronutrients, whose biochemical paths are saturated and distorted by pharmacological doses; and while vitamins remain im… more
Date: February 19, 2004
Creator: Hillegonds, Darren; Dueker, Stephen R.; Ognibene, Ted; Buchholz, Bruce A.; Lin, Yumei; Vogel, John S. et al.
Partner: UNT Libraries Government Documents Department
open access

High-Pressure Magnetic Susceptibility Experiments on the Heavy Lanthanides Gd, Tb, Dy, Ho, Er, and Tm

Description: The high pressure magnetic properties of the heavy lanthanide elements Gd, Tb, Dy, Ho, Er, and Tm have been investigated using ac magnetic susceptibility with a diamond anvil cell. It is found that the magnetic transition temperatures monotonically decrease with increasing pressure. In addition, the amplitudes of the magnetic transition signals decrease with increasing pressure, with the signals all eventually disappearing at pressures by 20 GPa. In contrast to previous studies, we see no evide… more
Date: November 19, 2004
Creator: Jackson, D. D.; Malba, V.; Weir, S. T.; Baker, P. A. & Vohra, Y. K.
Partner: UNT Libraries Government Documents Department
open access

Observation of Fluorine-Vacancy Complexes in Silicon

Description: We show direct evidence, obtained by positron annihilation spectroscopy, for the complexing of fluorine with vacancies in silicon. Both float zone and Czochralski silicon wafers were implanted with 30 keV fluorine ions to a fluence of 2x10{sup 14} ions/cm{sup 2}, and studied in the as-implanted condition, and after annealing to 650o C for 10 and for 30 minutes. The ''2-detector'' background reduction technique for positron annihilation was applied. The spectra reveal a significant concentration… more
Date: February 19, 2004
Creator: Jenei, Z.; Simpson, P. J.; Robison, R. R.; Asoka-Kumar, P. & Law, M. E.
Partner: UNT Libraries Government Documents Department
open access

Investigation of microstructure and V-defect formation inInxGa1-xN/GaN MQW grown using temperature-gradient MOCVD

Description: Temperature-gradient Metalorganic Chemical Vapor Deposition was used to deposit In{sub x}Ga{sub 1-x}N/GaN multiple quantum well structures with a concentration gradient of indium across the wafer. These multiple quantum well structures were deposited on low defect density (2 x 10{sup 8} cm{sup -2}) GaN template layers for investigation of microstructural properties and V-defect (pinhole) formation. Room temperature photoluminescence and photomodulated transmission were used for optical characte… more
Date: November 19, 2004
Creator: Johnson, M. C.; Liliental-Weber, Z.; Zakharov, D. N.; McCready, D. E.; Jorgenson, R. J.; Wu, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Special Analysis: Revised 14C Disposal Limits for the Saltstone Disposal Facility

Description: The Saltstone Special Analysis calculated a limit for 14C based on the atmospheric pathway of 52 pCi/mL using some very conservative assumptions. This was compared to the estimated Low Curie Salt concentration of 0.45 pCi/mL and since the limit was two orders of magnitude greater than the estimated concentration, the decision was made that no further analysis was needed. The 14C concentration in Tank 41 has been found to be much greater than the estimated concentration and to exceed the limit d… more
Date: March 19, 2004
Creator: Kaplan, D.I.
Partner: UNT Libraries Government Documents Department
open access

Electron avalanches in liquid argon mixtures

Description: We have observed stable avalanche gain in liquid argon when mixed with small amounts of xenon in the high electric field (>7 MV/cm) near the point of a chemically etched needle in a point-plane geometry. We identify two gain mechanisms, one pressure dependent, and the other independent of the applied pressure. We conclude that the pressure dependent signals are from avalanche gain in gas bubbles at the tip of the needle, while the pressure independent pulses are from avalanche gain in liquid… more
Date: March 19, 2004
Creator: Kim, J. G.; Dardin, S. M.; Kadel, R. W.; Kadyk, J. A.; Wenzel, W. B. & Peskov, V.
Partner: UNT Libraries Government Documents Department
open access

An Approach to Estimate the Localized Effects of an Aircraft Crash on a Facility

Description: Aircraft crashes are an element of external events required to be analyzed and documented in facility Safety Analysis Reports (SARs) and Nuclear Explosive Safety Studies (NESSs). This paper discusses the localized effects of an aircraft crash impact into the Device Assembly Facility (DAF) located at the Nevada Test Site (NTS), given that the aircraft hits the facility. This was done to gain insight into the robustness of the DAF and to account for the special features of the DAF that enhance it… more
Date: April 19, 2004
Creator: Kimura, C; Sanzo, D & Sharirli, M
Partner: UNT Libraries Government Documents Department
Back to Top of Screen