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Kinetic Studies of the Reactions Occurring Between Tungsten and Gases at Low Pressure and High Temperatures

Description: Oxygen, nitrogen, and nitric oxide gases were passed through a system consisting of a tungsten filament, an ion gauge, and a mass spectrometer. The ion gauge recorded total pressures and the spectrometer recorded partlal pressures of O/sub 2/, N/sub 2/, NO, CO, COa, and H/sub 2/O. From the way these pressures changed with filamert temperature, the rates of conversion of O/sub 2/ to volatile tungsten oxides and O, and of NO to volatile tungsten oxides N/sub 2/ , O/sub 2/, and O were computed. Th… more
Date: April 1, 1962
Creator: Anderson, H. U.
Partner: UNT Libraries Government Documents Department
open access

Heavy-Ion Elastic Scattering

Description: The elastic scattering of C/sup 12/ ions from Ar, Fe, Ni, Ag/sup 107/ In, and Ta was measured as a function of angle, at a laboratory-system energy of 124.5 Mev with the Berkeley heavy-ion linear accelerator. The experimental equipment and techniques are discussed. The angular distributions show the same general behavior as previous heavy-ion elastic scattering experiments. The experimental data were analyzed with the semiclassical Blair model as modified by McIntyre. Very good agreement with e… more
Date: April 17, 1961
Creator: Alster, Jonas
Partner: UNT Libraries Government Documents Department
open access

A search for particle dark matter using cryogenic germanium and silicon detectors in the one- and two- tower runs of CDMS-II at Soudan

Description: Images of the Bullet Cluster of galaxies in visible light, X-rays, and through gravitational lensing confirm that most of the matter in the universe is not composed of any known form of matter. The combined evidence from the dynamics of galaxies and clusters of galaxies, the cosmic microwave background, big bang nucleosynthesis, and other observations indicates that 80% of the universe's matter is dark, nearly collisionless, and cold. The identify of the dar, matter remains unknown, but weakly … more
Date: April 1, 2008
Creator: Ogburn, Reuben Walter, IV
Partner: UNT Libraries Government Documents Department
open access

Implementation of an interactive matching scheme for the Kapchinskij-Vladimirskij equations in the WARP code

Description: The WARP code is a robust electrostatic particle-in-cell simulation package used to model charged particle beams with strong space-charge forces. A fundamental operation associated with seeding detailed simulations of a beam transport channel is to generate initial conditions where the beam distribution is matched to the structure of a periodic focusing lattice. This is done by solving for periodic, matched solutions to a coupled set of ODEs called the Kapchinskij-Vladimirskij (KV) envelope equ… more
Date: April 15, 2008
Creator: Chilton, Sven H.
Partner: UNT Libraries Government Documents Department
open access

WW production cross section measurement and limits on anomalous trilinear gauge couplings at sqrt(s) = 1.96-TeV

Description: The cross section for WW production is measured and limits on anomalous WW{gamma} and WWZ trilinear gauge couplings are set using WW {yields} ee/e{mu}/{mu}{mu} events collected by the Run II D0 detector at the Fermilab Tevatron Collider corresponding to 1 fb{sup -1} of integrated luminosity at {radical}s = 1.96 TeV. Across the three final states, 108 candidate events are observed with 40.8 {+-} 3.8 total background expected, consistent with {sigma}(p{bar p} {yields} WW) = 11.6 {+-} 1.8(stat) {+… more
Date: April 1, 2008
Creator: Cooke, Michael P. & U., /Rice
Partner: UNT Libraries Government Documents Department
open access

Search for MSSM Higgs Boson Production in Proton Anti-Proton Collisions, with a Higgs Decaying into Taus

Description: We present a search for the production of neutral Higgs bosons in association with bottom quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The cross section for this process is enhanced in many extensions of the Standard Model (SM), such as in its Minimal Supersymmetric extension (MSSM) at large tan {beta}. The data, corresponding to a recorded integrated luminosity of 1 fb{sup -1}, were collected with the D0 detector at the Fermilab Tevatron Collider. In the absence of a signal a 95% C.… more
Date: April 1, 2008
Creator: Svoisky, Peter V. & U., /Notre Dame
Partner: UNT Libraries Government Documents Department
open access

Cross section measurements for quasi-elastic neutrino-nucleus scattering with the MINOS near detector

Description: The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory (FNAL) in Chicago, Illinois. MINOS measures neutrino interactions in two large iron-scintillator tracking/sampling calorimeters; the Near Detector on-site at FNAL and the Far Detector located in the Soudan mine in northern Minnesota. The Near Detector has recorded a large number of neutrino interactions and this high statistics dataset can b… more
Date: April 1, 2008
Creator: Dorman, Mark Edward & London, /University Coll.
Partner: UNT Libraries Government Documents Department
open access

Measurement of Inclusive Jet Cross Sections in Z/gamma*(->e+e-) + jets Production in ppbar Collisions at s**(1/2) = 1.96 TeV with the CDF Detector

Description: This Ph.D. thesis presents the measurement of inclusive jet cross sections in Z/{gamma}* {yields} e{sup +}e{sup -} events using 1.7 fb{sup -1} of data collected by the upgraded CDF detector during the Run II of the Tevatron. The Midpoint cone algorithm is used to search for jets in the events after identifying the presence of a Z/{gamma}* boson through the reconstruction of its decay products. The measurements are compared to next-to-LO (NLO) pQCD predictions for events with one and two jets in… more
Date: April 1, 2008
Creator: Salto Bauza, Oriol
Partner: UNT Libraries Government Documents Department
open access

Evidence for electroweak top quark production in proton-antiproton collisions at s**(1/2) = 1.96 TeV

Description: We present the first evidence for electroweak single top quark production using nearly 1 fb{sup -1} of Tevatron Run II data at {radical}s = 1.96 TeV. We select single-top-like data events in the lepton+jets decay channel and separate them from backgrounds using the matrix element analysis method. This technique uses leading order matrix elements to compute an event probability for both signal and background hypotheses. Using the expected signal acceptance, background, and observed data we measu… more
Date: April 1, 2007
Creator: Gadfort, Thomas & /Washington U., Seattle
Partner: UNT Libraries Government Documents Department
open access

Desulfurization of coal model compounds and coal liquids.

Description: Most US coals contain sulfur concentrations that prevent their being burned without some form of sulfur removal. Current coal-cleaning technology can only remove the fairly reactive pyritic (inorganic) and aliphatic (organic) sulfur. A process which removes the more refractory hetero-aromatic sulfur could substantially increase the amount of coal reserves amenable to chemical cleaning. Sodium metal dispersions convert refractor model compounds into lighter desulfurized products and non-volatile… more
Date: April 1, 1979
Creator: Wrathall, James Anthony & Peterson, Eugene E.
Partner: UNT Libraries Government Documents Department
open access

Soft x-ray streak camera for laser fusion applications

Description: This thesis reviews the development and significance of the soft x-ray streak camera (SXRSC) in the context of inertial confinement fusion energy development. A brief introduction of laser fusion and laser fusion diagnostics is presented. The need for a soft x-ray streak camera as a laser fusion diagnostic is shown. Basic x-ray streak camera characteristics, design, and operation are reviewed. The SXRSC design criteria, the requirement for a subkilovolt x-ray transmitting window, and the result… more
Date: April 1981
Creator: Stradling, Gary L.
Partner: UNT Libraries Government Documents Department
open access

Chemistry of coal model compounds: cleavage of aliphatic bridges between aromatic nuclei catalyzed by Lewis acids.

Description: The condensed polynuclear aromatic clusters of coal are believed to be linked principally by straight-chain aliphatic bridges varying from 0 to 4 carbon atoms in length and the cleavage of these linkages is expected to be an important step in the coal liquefaction process. This study focuses on the means by which Lewis acid catalysts, specifically AlCl/sub 3/ and ZnCl/sub 2/, promote the cleavage of these linkages. To facilitate product identification and interpretation of reaction mechanisms, … more
Date: April 1, 1978
Creator: Taylor, N. D.
Partner: UNT Libraries Government Documents Department
open access

The application of psoralens to the study of DNA structure, function and dynamics

Description: A series of six nitroxide spin-labeled psoralens were designed, synthesized and tested as probes for DNA dynamics. The synthesis of these spin-labeled psoralen derivatives and their photoreactivity with double-stranded DNA fragments is described. The spin labels (nitroxides) were demonstrated to survive the uv irradiation required to bind the probe to the target DNA. EPR spectra of the photobound spin-labels indicate that they do not wobble with respect to the DNA on the time-scales investigate… more
Date: April 1, 1991
Creator: Spielmann, P. H.
Partner: UNT Libraries Government Documents Department
open access

The effect of rhenium, sulfur and alumina on the conversion of hydrocarbons over platinum single crystals: Surface science and catalytic studies

Description: Conversion reactions of hydrocarbons over Pt-Re model catalyst surfaces modified by sulfur and alumina have been studied. A plasma deposition source has been developed to deposit Pt, Re, and Al on metal substrates variable coverage in ultrahigh vacuum without excessive heating. Conversion of n-hexane was performed over the Re-covered Pt and Pt-covered Re surfaces. The presence of the second metal increased hydrogenolysis activity of both Pt-Re surfaces. Addition of sulfur on the model Catalyst … more
Date: April 1, 1992
Creator: Kim, C.
Partner: UNT Libraries Government Documents Department
open access

Electromagnetic dissociation of {sup 238}U in heavy-ion collisions at 120 MeV/A

Description: This thesis describes a measurement of the heavy-ion induced electromagnetic dissociation of a 120 MeV/A {sup 238}U beam incident on five targets: {sup 9}Be, {sup 27}Al, {sup nat}Cu, {sup nat}Ag, and {sup nat}U. Electromagnetic dissociation at this beam energy is essentially a two step process involving the excitation of a giant resonance followed by particle decay. At 120 MeV/A there is predicted to be a significant contribution of the giant quadrupole resonance to the EMD cross sections. The … more
Date: April 1, 1991
Creator: Justice, M. L.
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

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

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

Behavior of the particle transport coefficients near the density limit in MTX

Description: The perturbed particle transport coefficients were determined for a range of plasma conditions in the Alcator C tokamak, a component of the Microwave Tokamak Experiment (MTX), from analysis of density perturbations created in gas modulation experiments. Density measurements from a 15 chord far-infrared interferometer were sufficiently detailed to allow radial profiles of the transport coefficients to be resolved. Gas modulation experiments were carried out on plasmas over a range of relatively … more
Date: April 1, 1993
Creator: Marinak, M. M.
Partner: UNT Libraries Government Documents Department
open access

Independent verification and validation of large software requirement specification databases

Description: To enhance quality, an independent verification and validation (IV&V) review is conducted as software requirements are defined. Requirements are inspected for consistency and completeness. IV&V strives to detect defects early in the software development life cycle and to prevent problems before they occur. The IV&V review process of a massive software requirements specification, the Reserve Component Automation System (RCAS) Functional Description (FD) is explored. Analysis of the RCAS FD error… more
Date: April 1, 1992
Creator: Twitchell, K. E.
Partner: UNT Libraries Government Documents Department
open access

Electronic and structural properties of metallic microclusters

Description: The first part of this thesis presents a first-order pseudopotential calculation at T=O of the total energy of small sodium clusters of size N<800. The calculation is based on a local-pseudopotential scheme and local-density correlation and exchange. A temperature-size (T-N) phase-diagram is then derived using the T=O results and Lindemann`s criterion for melting. The phase-diagram contains three regions of stability: (1) a liquid (jellium) phase at temperatures above the melting line T{sub M}(… more
Date: April 1, 1992
Creator: Maiti, A.
Partner: UNT Libraries Government Documents Department
open access

Crossed molecular beam studies of atmospheric chemical reaction dynamics

Description: The dynamics of several elementary chemical reactions that are important in atmospheric chemistry are investigated. The reactive scattering of ground state chlorine or bromine atoms with ozone molecules and ground state chlorine atoms with nitrogen dioxide molecules is studied using a crossed molecular beams apparatus with a rotatable mass spectrometer detector. The Cl + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at four collision energies ranging from 6 kcal/mole to 32 kcal/mol… more
Date: April 1, 1993
Creator: Zhang, Jingsong
Partner: UNT Libraries Government Documents Department
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