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Modeling Free Convection Flow of Liquid Hydrogen within a Cylindrical Heat Exchanger Cooled to 14 K

Description: A liquid hydrogen in a absorber for muon cooling requires that up to 300 W be removed from 20 liters of liquid hydrogen. The wall of the container is a heat exchanger between the hydrogen and 14 K helium gas in channels within the wall. The warm liquid hydrogen is circulated down the cylindrical walls of the absorber by free convection. The flow of the hydrogen is studied using FEA methods for two cases and the heat transfer coefficient to the wall is calculated. The first case is when the wall… more
Date: May 8, 2004
Creator: Green, Michael A.; Yang, S. W.; Green, M. A. & Lau, W.
Partner: UNT Libraries Government Documents Department
open access

Comments on Shimony's 'An Analysis of Stapp's 'A bell-type theoremwithout hidden variables''

Description: The hidden-variable theorems of Bell and followers depend upon an assumption, namely the hidden-variable assumption, that conflicts with the precepts of quantum philosophy. Hence from an orthodox quantum perspective those theorems entail no faster-than-light transfer of information. They merely reinforce the ban on hidden variables. The need for some sort of faster-than-light information transfer can be shown by using counterfactuals instead of hidden variables. Shimony's criticism of that argu… more
Date: September 8, 2004
Creator: Stapp, Henry P.
Partner: UNT Libraries Government Documents Department
open access

Transition to Turbulence and Effect of Initial Conditions on 3D Compressible Mixing in Planar Blast-wave-driven Systems

Description: Perturbations on an interface driven by a strong blast wave grow in time due to a combination of Rayleigh-Taylor, Richtmyer-Meshkov, and decompression effects. In this paper, results from three-dimensional numerical simulations of such a system under drive conditions to be attainable on the National Ignition Facility [E. M. Campbell, Laser Part. Beams, 9(2), 209 (1991)] are presented. Using the multi-physics, adaptive mesh refinement, higher order Godunov Eulerian hydrocode, Raptor [L. H. Howel… more
Date: November 8, 2004
Creator: Miles, A R; Edwards, M J & Greenough, J A
Partner: UNT Libraries Government Documents Department
open access

Use of Conducting Polymers for Electronic Communication with Redox Active Nanoparticles

Description: Nanoscale materials provide unique properties that will enable new technologies and enhance older ones. One area of intense activity in which nanoscale materials are being used is in the development of new functional materials for battery applications.1-4 This effort promises superior materials with properties that circumvent many of the problems associated with traditional battery materials. Previously we have worked on several approaches for using nanoscale materials for application as cathod… more
Date: August 8, 2004
Creator: Bazito, Fernanda; O'Brien, Robert & Buttry, Daniel A.
Partner: UNT Libraries Government Documents Department
open access

Defects in p-GaN and their atomic structure

Description: In this paper defects formed in p-doped GaN:Mg grown with Ga polarity will be discussed. The atomic structure of these characteristic defects (Mg-rich hexagonal pyramids and truncated pyramids) in bulk and thin GaN:Mg films grown with Ga polarity was determined at atomic resolution by direct reconstruction of the scattered electron wave in a transmission electron microscope. Small cavities were present inside the defects. The inside walls of the cavities were covered by GaN which grew with reve… more
Date: October 8, 2004
Creator: Liliental-Weber, Z.; Tomaszewicz, T.; Zakharov, D.; Jasinski, J. & and O'Keefe, M.
Partner: UNT Libraries Government Documents Department
open access

Wintertime pytoplankton bloom in the Subarctic Pacific supportedby continental margin iron

Description: Heightened biological activity was observed in February 1996in the high-nutrient low-chlorophyll (HNLC) subarctic North PacificOcean, a region that is thought to beiron-limited. Here we provideevidence supporting the hypothesis that Ocean Station Papa (OSP) in thesubarctic Pacific received a lateral supply of particulate iron from thecontinental margin off the Aleutian Islands in the winter, coincidentwith the observed biological bloom. Synchrotron X-ray analysis was usedto describe the physica… more
Date: June 8, 2004
Creator: Lam, Phoebe J.; Bishop, James K.B.; Henning, Cara C.; Marcus,Matthew A.; Waychunas, Glenn A. & Fung, Inez
Partner: UNT Libraries Government Documents Department
open access

Probability Density Function for Waves Propagating in a Straight PEC Rough Wall Tunnel

Description: The probability density function for wave propagating in a straight perfect electrical conductor (PEC) rough wall tunnel is deduced from the mathematical models of the random electromagnetic fields. The field propagating in caves or tunnels is a complex-valued Gaussian random processing by the Central Limit Theorem. The probability density function for single modal field amplitude in such structure is Ricean. Since both expected value and standard deviation of this field depend only on radial p… more
Date: November 8, 2004
Creator: Pao, H
Partner: UNT Libraries Government Documents Department
open access

Numerical Modeling of Nonlinear Thermodynamics in SMA Wires

Description: We present a mathematical model describing the thermodynamic behavior of shape memory alloy wires, as well as a computational technique to solve the resulting system of partial differential equations. The model consists of conservation equations based on a new Helmholtz free energy potential. The computational technique introduces a viscosity-based continuation method, which allows the model to handle dynamic applications where the temporally local behavior of solutions is desired. Computationa… more
Date: January 8, 2004
Creator: Reynolds, D R & Kloucek, P
Partner: UNT Libraries Government Documents Department
open access

A Comparison of Inexact Newton and Coordinate Descent Meshoptimization Technqiues

Description: We compare inexact Newton and coordinate descent methods for optimizing the quality of a mesh by repositioning the vertices, where quality is measured by the harmonic mean of the mean-ratio metric. The effects of problem size, element size heterogeneity, and various vertex displacement schemes on the performance of these algorithms are assessed for a series of tetrahedral meshes.
Date: July 8, 2004
Creator: Diachin, L F; Knupp, P; Munson, T & Shontz, S
Partner: UNT Libraries Government Documents Department
open access

SEISMIC DATA FOR NUCLEAR EXPLOSION MONITORING IN THE ARABIAN PENINSULA

Description: We report results from the third and final year of our project (ROA0101-35) to collect seismic event and waveform data recorded in and around the Arabian Peninsula. This effort involves several elements. We are working with King Abdulaziz City for Science and Technology to collect data from the Saudi National Seismic Network, that consists of 38 digital three-component stations (27 broadband and 11 short-period). We have an ongoing collaboration with the Kuwait Institute for Scientific Research… more
Date: July 8, 2004
Creator: Rodgers, A. & Al-Amri, A.
Partner: UNT Libraries Government Documents Department
open access

No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces

Description: The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.
Date: January 8, 2004
Creator: Barrett, B R; Vary, J P; Nogga, A; Navratil, P & Ormand, W E
Partner: UNT Libraries Government Documents Department
open access

Fracture Permeability Evolution in Rock from the Desert Peak EGS Site

Description: Fluid flow experiments are being conducted on core specimens of quartz monzonite retrieved from depths of about 1 km at the Desert Peak East EGS site in Churchill County, Nevada. Our immediate goal is to observe permeability evolution in fractures at pressure and temperature conditions appropriate to the Desert Peak geothermal site. Longer term, we aim to evaluate mechanisms that control the evolution of fracture permeability. In the experiments saline water is flowed through an artificial frac… more
Date: April 8, 2004
Creator: Carlson, S. R.; Roberts, J. J.; Detwiler, R. L.; Burton, E. A.; Robertson-Tait, A.; Morris, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Laboratory Measurements of Velocity and Attenuation in Sediments

Description: Laboratory measurements are required to establish relationships between the physical properties of unconsolidated sediments and P- and S-wave propagation through them. Previous work has either focused on measurements of compressional wave properties at depths greater than 500 m for oil industry applications or on measurements of dynamic shear properties at pressures corresponding to depths of less than 50 m for geotechnical applications. Therefore, the effects of lithology, fluid saturation, an… more
Date: June 8, 2004
Creator: Zimmer, M A; Berge, P A; Bonner, B P & Prasad, M
Partner: UNT Libraries Government Documents Department
open access

What can we learn from neutrinoless double beta decay experiments?

Description: We assess how well next generation neutrinoless double beta decay and normal neutrino beta decay experiments can answer four fundamental questions. 1) If neutrinoless double beta decay searches do not detect a signal, and if the spectrum is known to be inverted hierarchy, can we conclude that neutrinos are Dirac particles? 2) If neutrinoless double beta decay searches are negative and a next generation ordinary beta decay experiment detects the neutrino mass scale, can we conclude that neutrino… more
Date: April 8, 2004
Creator: Bahcall, John N.; Murayama, Hitoshi & Pena-Garay, Carlos
Partner: UNT Libraries Government Documents Department
open access

Study of Dark Matter inspired cMSSM scenarios at a TeV-class Linear Collider

Description: The accuracy in the measurement of the masses of sleptons and heavy Higgs bosons in cMSSM scenarios, compatible with the WMAP result on cold dark matter, has been re-analysed in view of the requirements for predicting this density to a few percent level from SUSY measurements at the linear collider.
Date: October 8, 2004
Creator: Battaglia, Marco
Partner: UNT Libraries Government Documents Department
open access

Antenna-coupled bolometer arrays using transition-edgesensors

Description: We describe the development of an antenna-coupled bolometer array for use in a Cosmic Microwave Background polarization experiment. Prototype single pixels using double-slot dipole antennas and integrated microstrip band defining filters have been built and tested. Preliminary results of optical testing and simulations are presented. A bolometer array design based on this pixel will also be shown and future plans for application of the technology will be discussed.
Date: June 8, 2004
Creator: Myers, Michael J.; Ade, Peter; Engargiola, Greg; Holzapfel,William; Lee,Adrian T.; O'Brient, Roger et al.
Partner: UNT Libraries Government Documents Department
open access

Analysis of TPV Network Losses (a Presentation)

Description: This talk focuses on the theoretical analysis of electrical losses associated with electrically networking large numbers of TPV cells to produce high power TPV power generators.
Date: December 8, 2004
Creator: DePoy, DM; Dashiell, MW; Rahner, DD; Danielson, LR; Oppenlander, JE; Vell, JL et al.
Partner: UNT Libraries Government Documents Department
open access

Proteomic profiling of bone marrow mesenchymal stem cells upon TGF-beta stimulation

Description: Bone marrow mesenchymal stem cells (MSCs) can differentiate into different types of cells, and have tremendous potential for cell therapy and tissue engineering. Transforming growth factor {beta}1 (TGF-{beta}) plays an important role in cell differentiation and vascular remodeling. We showed that TGF-{beta} induced cell morphology change and an increase in actin fibers in MSCs. To determine the global effects of TGF-{beta} on MSCs, we employed a proteomic strategy to analyze the effect of TGF-{… more
Date: August 8, 2004
Creator: Wang, Daojing; Park, Jennifer S.; Chu, Julia S.F.; Ari, Krakowski; Luo, Kunxin; Chen, David J. et al.
Partner: UNT Libraries Government Documents Department
open access

Empirical analysis of the spot market implications ofprice-elastic demand

Description: Regardless of the form of restructuring, deregulated electricity industries share one common feature: the absence of any significant, rapid demand-side response to the wholesale (or, spotmarket) price. For a variety of reasons, electricity industries continue to charge most consumers an average cost based on regulated retail tariff from the era of vertical integration, even as the retailers themselves are forced to purchase electricity at volatile wholesale prices set in open markets. This resu… more
Date: July 8, 2004
Creator: Siddiqui, Afzal S.; Bartholomew, Emily S. & Marnay, Chris
Partner: UNT Libraries Government Documents Department
open access

The photon polarization in b -> X gamma in the standard model

Description: The standard model prediction for the {bar B}{sup 0} {yields} X{sub s,d}{gamma} decay amplitude with a right-handed photon is believed to be tiny, suppressed by m{sub s,d}/m{sub b}, compared to the amplitude with a left-handed photon. We show that this suppression is fictitious: in inclusive decays, the ratio of these two amplitudes is only suppressed by g{sub s}/(4{pi}), and in exclusive decays by {Lambda}{sub QCD}/m{sub b}. The suppression is not stronger in {bar B}{sup 0} {yields} X{sub d}{g… more
Date: December 8, 2004
Creator: Grinstein, Benjamin; Grossman, Yuval; Ligeti, Zoltan & Pirjol, Dan
Partner: UNT Libraries Government Documents Department
open access

High Level Waste (HLW) Processing Experience with Increased Waste Loading

Description: The Defense Waste Processing Facility (DWPF) Engineering requested characterization of glass samples that were taken after the second melter had been operational for about 5 months. After the new melter had been installed, the waste loading had been increased to about 38 weight percentage after a new quasicrystalline liquidus model had been implemented. The DWPF had also switched from processing with refractory Frit 200 to a more fluid Frit 320. The samples were taken after DWPF observed very r… more
Date: June 8, 2004
Creator: JANTZEN, CAROL
Partner: UNT Libraries Government Documents Department
open access

High quality electron beams from a plasma channel guided laser wakefield accelerator

Description: Laser driven accelerators, in which particles are accelerated by the electric field of a plasma wave driven by an intense laser, have demonstrated accelerating electric fields of hundreds of GV/m. These fields are thousands of times those achievable in conventional radiofrequency (RF) accelerators, spurring interest in laser accelerators as compact next generation sources of energetic electrons and radiation. To date however, acceleration distances have been severely limited by lack of a contro… more
Date: July 8, 2004
Creator: Geddes, C. G. R.; Toth, Cs.; van Tilborg, J.; Esarey, E.; Schroeder, C. B.; Bruhwiler, D. et al.
Partner: UNT Libraries Government Documents Department
open access

Layered manganese oxide intergrowth electrodes for rechargeable lithium batteries: Part 1-substitution with Co or Ni

Description: Lithium manganese oxides substituted with nickel or cobalt were characterized electrochemically in lithium cell configurations. The compounds studied were either single-phase layered structures with either primarily O2 or O3 stacking arrangements, or O2/O3 intergrowths, prepared from P2, P3 and P2/P3 sodium-containing precursors, respectively. The stacking arrangements are extremely sensitive to the Na/T. M. (T. M. = transition metal) ratios and the level of substitution. Phase diagrams showing… more
Date: September 8, 2004
Creator: Dolle, Mickael; Patoux, Sebastien & Doeff, Marca M.
Partner: UNT Libraries Government Documents Department
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