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Thermal modeling of the lithium/polymer battery

Description: Research in the area of advanced batteries for electric-vehicle applications has increased steadily since the 1990 zero-emission-vehicle mandate of the California Air Resources Board. Due to their design flexibility and potentially high energy and power densities, lithium/polymer batteries are an emerging technology for electric-vehicle applications. Thermal modeling of lithium/polymer batteries is particularly important because the transport properties of the system depend exponentially on tem… more
Date: October 1, 1994
Creator: Pals, C. R.
Partner: UNT Libraries Government Documents Department
open access

The photosynthetic acclimation of Lolium perenne growing in a free-air CO{sub 2} enrichment (FACE) system

Description: Stands of Ryegrass (Lolium perenne L. cv. Bastion) were grown in the field at ambient or elevated (600{mu}mol/mol) CO{sub 2} concentration, high (560Kg/ha) or low (140Kg/ha) nitrogen addition and with a frequent (every 4 weeks) or infrequent (every 8 weeks) cutting regime. Plants were in the second year of a 3 year experiment. Exposure to elevated CO{sub 2} was carried out with a Free-Air CO{sub 2} Enrichment (FACE) system which provides the most {open_quote}realistic{close_quote} system of CO{… more
Date: November 1, 1994
Creator: Bryant, J. B.
Partner: UNT Libraries Government Documents Department
open access

Vibrational spectroscopy of water interfaces

Description: The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful and versatile tools for studying all kinds of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the second order nonlinear susceptibility. The technique of infrared-visible sum frequency generation (SFG) is particularly attractive because it offers a viable way to do vibrational spectroscopy on any surfaces accessible to light with submonolayer … more
Date: December 1, 1994
Creator: Du, Q.
Partner: UNT Libraries Government Documents Department
open access

A photoemission study of the diamond and the single crystal C{sub 60}

Description: This report studied the elctronic structure of diamond (100) and diamond/metal interface and C{sub 60}, using angle-resolved and core level photoemission. The C(100)-(2X1) surface electronic structure was studied using both core level and angle resolved valence band photoemission spectroscopy. The surface component of the C 1s core level spectrum agrees with theoretical existence of only symmetrical dimers. In the case of metal/diamond interfaces, core level and valence photoelectron spectrosco… more
Date: March 1, 1994
Creator: Wu, Jin
Partner: UNT Libraries Government Documents Department
open access

Pion single charge exchange in three body nuclei at intermediate energies

Description: The purpose of this thesis is to present new experimental information about modifications to the pion-nucleon single charge exchange interaction, {pi}{sup +}n {yields}{pi}{sup 0} p or {pi}{sup {minus}} p {yields} {pi}{sup 0}n, due to the presence of other nucleons. The results of two experimental studies of pion single charge exchange in the three nucleon system near the {triangle}-resonance are presented. Both of these experiments were performed at the Clinton P. Anderson Meson Physics Facilit… more
Date: January 1, 1994
Creator: Dowell, M. L.
Partner: UNT Libraries Government Documents Department
open access

Magnetohydrodynamic simulation of solid-deuterium-initiated Z-pinch experiments

Description: Solid-deuterium-initiated Z-pinch experiments are numerically simulated using a two-dimensional resistive magnetohydrodynamic model, which includes many important experimental details, such as ``cold-start`` initial conditions, thermal conduction, radiative energy loss, actual discharge current vs. time, and grids of sufficient size and resolution to allow realistic development of the plasma. The alternating-direction-implicit numerical technique used meets the substantial demands presented by … more
Date: February 1, 1994
Creator: Sheehey, P. T.
Partner: UNT Libraries Government Documents Department
open access

Toward resolving model-measurement discrepancies of radon entry into houses

Description: Analysis of the literature indicated that radon transport models significantly and consistently underpredict the advective entry into houses of soil-gas borne radon. Advective entry is the dominant mechanism resulting in high concentrations of radon indoors. The author investigated the source of the model-measurement discrepancy via carefully controlled field experiments conducted at an experimental basement located in natural soil in Ben Lomond, California. Early experiments at the structure c… more
Date: October 1, 1994
Creator: Garbesi, K.
Partner: UNT Libraries Government Documents Department
open access

Measurement of magnetic turbulence structure and nonlinear mode coupling of tearing fluctuations in the Madison Symmetric Torus reversed field pinch edge

Description: Linear and nonlinear magnetohydrodynamic (MHD) stability of current-driven modes are studied in the MST reversed field pinch. Measured low frequency (f < 35 kHz) magnetic fluctuations are consistent with the global resistive tearing instabilities predicted by 3-D MHD simulations. At frequencies above 35 kHz, the magnetic fluctuations were detected to be localized and externally resonant. Discrete dynamo events, ``sawtooth oscillations,`` have been observed in the experimental RFP plasmas. This … more
Date: January 1, 1994
Creator: Assadi, S.
Partner: UNT Libraries Government Documents Department
open access

Instability heating of solid-fiber Z pinches

Description: The Los Alamos High Density Z Pinch-II (HDZP-II) facility is used to study the dynamics of z-pinch plasmas generated from solid fibers of deuterated polyethylene CD{sub 2} with a range in radii of 3--60 {mu}m. HDZP-II is a pulsed-power generator that delivers a current that rises to 700 kA in 100 ns through an inductive load. A multiframe circular schlieren records the evolution of the shape and size of the plasma on seven images taken at 10-ns intervals. These circular-schlieren images show ve… more
Date: February 1, 1994
Creator: Riley, R. A. Jr.
Partner: UNT Libraries Government Documents Department
open access

Z + {gamma} cross-section measurement, {sigma}*BR(Z + {gamma}), in the electron channel for p{bar p} collisions at {radical}s = 1.8 TeV, and limits for the ZZ{gamma} and Z{gamma}{gamma} anomalous couplings

Description: The Z + {gamma} cross-section x branching ratio in the electron channel has been measured using the inclusive Z data sample from the CDF 1988--1989 collider run, for which the total integrated luminosity was 4.05 {plus_minus} 0.28 pb{sup {minus}1}. Two Z{gamma} candidates are observed from central photon events with {Delta}R/{sub {gamma}} > 0.7 and E{sub t}{sup {gamma}} > 5.0 GeV. From these events the {sigma} * BR(Z + {gamma}) is measured and compared with SM predictions: {sigma} * BR(Z + {gam… more
Date: February 1, 1994
Creator: Roach-Bellino, M.
Partner: UNT Libraries Government Documents Department
open access

Fate of polycyclic aromatic hydrocarbons in plant-soil systems: Plant responses to a chemical stress in the root zone

Description: Under laboratory conditions selected to maximize root uptake, plant tissue distribution of PAH-derived {sup 14}C was largely limited to root tissue of Malilotus alba. These results suggest that plant uptake of PAHs from contaminated soil via roots, and translocation to aboveground plant tissues (stems and leaves), is a limited mechanism for transport into terrestrial food chains. However, these data also indicate that root surface sorption of PAHs may be important for plants grown in soils cont… more
Date: January 1, 1994
Creator: Hoylman, A. M. & Walton, B. T.
Partner: UNT Libraries Government Documents Department
open access

Models to evaluate magnicon architectures and designs suitable for high-perveance beams

Description: The magnicon, a new high-power, radio frequency (rf) deflection- modulated amplifier, was recently developed at the Institute for Nuclear Physics in Novosibirsk, Russia. The first magnicon achieved a peak output power of 2.6 MW for 50-{mu}s pulses at a frequency of 915 MHz with a dc-to-rf conversion efficiency of 73%. The conversion efficiency achieved by the original magnicon represents a significant improvement over state-of-the-art conventional velocity- and density-modulated devices. Theref… more
Date: March 1, 1994
Creator: Rees, D. E.
Partner: UNT Libraries Government Documents Department
open access

A calorimetric measurement of the strong coupling constant in electron-positron annihilation at a center-of-mass energy of 91.6 GeV

Description: In this work, a measurement of the strong coupling constant {alpha}{sub s} in e{sup +}e{sup {minus}} annihilation at a center-of-mass energy of 91.6 GeV is presented. The measurement was performed with the SLD at the Stanford Linear Collider facility located at the Stanford Linear Accelerator Center in California. The procedure used consisted of measuring the rate of hard gluon radiation from the primary quarks in a sample of 9,878 hadronic events. After defining the asymptotic manifestation of… more
Date: April 1, 1994
Creator: Martirena, S. G.
Partner: UNT Libraries Government Documents Department
open access

A research study to determine the effect of Total Quality Management (TQM) on employee morale in Plant Procedures Division at EG&G, Rocky Flats, Inc.

Description: EG&G at Rocky Flats, Golden, Colorado, experienced a high amount of low morale, due to the plant site having been designated to close, and the uneasiness of the working force was very visible. Some employees accepted early retirement in October 1992, however, all received letters of 120 days notice in March 1993, and were advised several cuts Would be made by October 1, 1993. This information alone caused many insecurities in employees, and caused morale to decrease even more. This is an in dep… more
Date: January 1, 1994
Creator: Casey, E. F.
Partner: UNT Libraries Government Documents Department
open access

High resolution electron diffraction analysis of structural changes associated with the photocycle of bacteriorhodopsin

Description: Changes in protein structure that occur during the formation of the M photointermediate of bacteriorhodopsin can be directly visualized by electron diffraction techniques. Samples containing a high percentage of the M intermediate were trapped by rapidly cooling the crystals with liquid nitrogen following illumination with filtered green light at 240K and 260K respectively. Difference Fourier projection maps for M minus bR at two temperatures and for M{sub 260K} minus M{sub 240K} are presented.… more
Date: April 1, 1994
Creator: Han, B.-G.
Partner: UNT Libraries Government Documents Department
open access

Hadronic wavefunctions in light-cone quantization

Description: The analysis of light-cone wavefunctions seems the most promising theoretical approach to a detailed understanding of the structure of relativistic bound states, particularly hadrons. However, there are numerous complications in this approach. Most importantly, the light-cone approach sacrifices manifest rotational invariance in exchange for the elimination of negative-energy states. The requirement of rotational invariance of the full theory places important constraints on proposed light-cone … more
Date: May 1, 1994
Creator: Hyer, T.
Partner: UNT Libraries Government Documents Department
open access

The crosswell electromagnetic response of layered media

Description: Crosswell electromagnetic measurements are a promising new geophysical technique for mapping subsurface electrical conductivity which can provide information about the subsurface distribution of water, oil or steam. In this work the fields from a low frequency vertical magnetic dipole have been examined from the specific point of view of their application to the determination of the conductivity of a layered medium. The source and the receiver were placed inside two separate boreholes. The rang… more
Date: April 1, 1994
Creator: Deszcz-Pan, M.
Partner: UNT Libraries Government Documents Department
open access

Time-resolved electron thermal conduction by probing of plasma formation in transparent solids with high power subpicosecond laser pulses

Description: This dissertation work includes a series of experimental measurements in a search for better understanding of high temperature (10{sup 4}-10{sup 6}K) and high density plasmas (10{sup 22}-10{sup 24}cm{sup {minus}3}) produced by irradiating a transparent solid target with high intensity (10{sup 13} - 10{sup 15}W/cm{sup 2}) and subpicosecond (10{sup {minus}12}-10{sup {minus}13}s) laser pulses. Experimentally, pump and probe schemes with both frontside (vacuum-plasma side) and backside (plasma-bulk… more
Date: February 1, 1994
Creator: Vu, B. T. V.
Partner: UNT Libraries Government Documents Department
open access

Quaternary liquid/liquid equilibria of sodium sulfate, sodium sulfite and water with two solvents: Acetone and 2-propanol

Description: Aqueous solutions of sodium sulfate and sodium sulfite are produced from sodium carbonate in flue-gas scrubbers; recovery of these salts often requires multi-effect evaporators; however, a new energy-efficient unit operation called extractive crystallization has been shown to have reduced energy costs. In this process, an organic solvent is added to the aqueous salt solution to precipitate salt. Acetone is a suitable solvent for this process, better than 2-propanol. Liquid/liquid/solid equilibr… more
Date: March 1, 1994
Creator: Schiozer, A. L.
Partner: UNT Libraries Government Documents Department
open access

An investigation of the vortex method

Description: The vortex method is a numerical scheme for solving the vorticity transport equation. Chorin introduced modern vortex methods. The vortex method is a Lagrangian, grid free method which has less intrinsic diffusion than many grid schemes. It is adaptive in the sense that elements are needed only where the vorticity is non-zero. Our description of vortex methods begins with the point vortex method of Rosenhead for two dimensional inviscid flow, and builds upon it to eventually cover the case of t… more
Date: May 1, 1994
Creator: Pryor, D. W. Jr.
Partner: UNT Libraries Government Documents Department
open access

Ion beam synthesis of SiGe alloy layers

Description: Procedures required for minimizing structural defects generated during ion beam synthesis of SiGe alloy layers were studied. Synthesis of 200 mm SiGe alloy layers by implantation of 120-keV Ge ions into <100> oriented Si wafers yielded various Ge peak concentrations after the following doses, 2{times}10{sup 16}cm{sup {minus}2}, 3{times}10{sup 16}cm{sup {minus}2} (mid), and 5{times}10{sup 16}cm{sup {minus}2} (high). Following implantation, solid phase epitaxial (SPE) annealing in ambient N2 at 8… more
Date: May 1, 1994
Creator: Im, Seongil
Partner: UNT Libraries Government Documents Department
open access

Resonant tunneling in small current-biased Josephson Junctions

Description: Effects of resonant tunneling between bound quantum states of a current-biased Josephson tunnel junction is studied both theoretically and experimentally. Several effects are predicted to arise from resonant tunneling, including a series of voltage peaks along the supercurrent branch of the current-voltage characteristic, and enhanced rate of escape from zero voltage state to voltage state at particular values of bias current. A model is developed to estimate magnitude and duration of voltage p… more
Date: May 1, 1994
Creator: Schmidt, J. M.
Partner: UNT Libraries Government Documents Department
open access

Zone Refining of Plutonium Metal

Description: The zone refining process was applied to Pu metal containing known amounts of impurities. Rod specimens of plutonium metal were melted into and contained in tantalum boats, each of which was passed horizontally through a three-turn, high-frequency coil in such a manner as to cause a narrow molten zone to pass through the Pu metal rod 10 times. The impurity elements Co, Cr, Fe, Ni, Np, U were found to move in the same direction as the molten zone as predicted by binary phase diagrams. The elemen… more
Date: August 1, 1994
Creator: Blau, M. S.
Partner: UNT Libraries Government Documents Department
open access

Topics in the structure of hadronic systems

Description: In this dissertation the author examines a variety of different problems in the physics of strongly-bound systems. Each is elucidated by a different standard method of analysis developed to probe the properties of such systems. He begins with an examination of the properties and consequences of the current algebra of weak currents in the limit of heavy quark spin-flavor symmetry. In particular, he examines the assumptions in the proof of the Ademollo-Gatto theorem in general and for spin-flavor… more
Date: April 1, 1994
Creator: Lebed, R. F.
Partner: UNT Libraries Government Documents Department
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