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Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering

Description: The XRMS experiment on the Gd{sub 5}Ge{sub 4} system has shown that, below the Neel temperature, T{sub N} = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic sla… more
Date: August 18, 2008
Creator: Tan, Lizhi
Partner: UNT Libraries Government Documents Department
open access

Search for new physics in the Compact Muon Solenoid (CMS) experiment and the response of the CMS calorimeters to particles and jets

Description: A Monte Carlo study of a generic search for new resonances beyond the Standard Model (SM) in the CMS experiment is presented. The resonances are axigluon, coloron, E{sub 6} diquark, excited quark, W{prime}, Z{prime}, and the Randall-Sundrum graviton which decay to dijets. The dijet resonance cross section that the CMS can expect to discover at a 5{sigma} significance or to exclude at 95% confidence level for integrated luminosities of 100 pb{sup -1}, 1 fb{sup -1}, and 10 fb{sup -1} is evaluated… more
Date: August 1, 2008
Creator: Gumus, Kazim Ziya & Tech., /Texas
Partner: UNT Libraries Government Documents Department
open access

Type Ia supernova rate studies from the SDSS-II Supernova Study

Description: The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered {approx} 500 spectroscopically confirmed SNe Ia with densely sampled (once every {approx} 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of typ… more
Date: August 1, 2008
Creator: Dilday, Benjamin
Partner: UNT Libraries Government Documents Department
open access

Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

Description: Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed… more
Date: August 18, 2008
Creator: Saetveit, Nathan Joe
Partner: UNT Libraries Government Documents Department
open access

Search for Higgs bosons decaying into tau pairs in ppbar collisions at D0

Description: A search for neutral Higgs bosons decaying into tau pairs is presented using data in p{bar p} collisions at {radical}s = 1.96 TeV. One of the tau leptons is identified via its decay into an electron or muon and the other via its decay into a hadronic final state. The data, corresponding to an integrated luminosity of around 1.0 fb{sup -1}, were collected with the D0 detector at the Fermilab Tevatron collider between April 2002 and February 2006. No significant excess of events above the backgro… more
Date: August 1, 2008
Creator: Owen, Mark A.
Partner: UNT Libraries Government Documents Department
open access

Novel Bioplastics and biocomposites from Vegetable Oils

Description: Polymeric materials have been prevalent in our everyday lives for quite a long time. Most of today's polymeric materials are derived from nonrenewable petroleum-based feedstocks. Instabilities in the regions where petroleum is drilled, along with an increased demand in petroleum, have driven the price of crude oil to record high prices. This, in effect, increases the price of petroleum-based polymeric materials, which has caused a heightened awareness of renewable alternatives for polymeric fee… more
Date: August 18, 2008
Creator: Henna, Phillip H.
Partner: UNT Libraries Government Documents Department
open access

Synthesis and Characterization of Smart Block Copolymers for Biomineralization and Biomedical Applications

Description: Self-assembly is a powerful tool in forming structures with nanoscale dimensions. Self-assembly of macromolecules provides an efficient and rapid pathway for the formation of structures from the nanometer to micrometer range that are difficult, if not impossible to obtain by conventional lithographic techniques [1]. Depending on the morphologies obtained (size, shape, periodicity, etc.) these self-assembled systems have already been applied or shown to be useful for a number of applications in … more
Date: August 18, 2008
Creator: Kanapathipillai, Mathumai
Partner: UNT Libraries Government Documents Department
open access

Effects of Substrate and Co-Culture on Neural Progenitor Cell Differentiation

Description: In recent years the study of stem and progenitor cells has moved to the forefront of research. Since the isolation of human hematopoietic stem cells in 1988 and the subsequent discovery of a self renewing population of multipotent cells in many tissues, many researchers have envisioned a better understanding of development and potential clinical usage in intractable diseases. Both these goals, however, depend on a solid understanding of the intracellular and extracellular forces that cause stem… more
Date: August 18, 2008
Creator: Jones, Erin Boote
Partner: UNT Libraries Government Documents Department
open access

Determination of NAD+ and NADH level in a Single Cell Under H2O2 Stress by Capillary Electrophoresis

Description: A capillary electrophoresis (CE) method is developed to determine both NAD{sup +} and NADH levels in a single cell, based on an enzymatic cycling reaction. The detection limit can reach down to 0.2 amol NAD{sup +} and 1 amol NADH on a home-made CE-LIF setup. The method showed good reproducibility and specificity. After an intact cell was injected into the inlet of a capillary and lysed using a Tesla coil, intracellular NAD{sup +} and NADH were separated, incubated with the cycling buffer, and q… more
Date: August 18, 2008
Creator: Xi, Wenjun
Partner: UNT Libraries Government Documents Department
open access

Diagnostics of the Fermilab Tevatron using an AC dipole

Description: The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for th… more
Date: August 1, 2008
Creator: Miyamoto, Ryoichi
Partner: UNT Libraries Government Documents Department
open access

Structural and Electronic Investigations of Complex Intermetallic Compounds

Description: In solid state chemistry, numerous investigations have been attempted to address the relationships between chemical structure and physical properties. Such questions include: (1) How can we understand the driving forces of the atomic arrangements in complex solids that exhibit interesting chemical and physical properties? (2) How do different elements distribute themselves in a solid-state structure? (3) Can we develop a chemical understanding to predict the effects of valence electron concentr… more
Date: August 18, 2008
Creator: Ko, Hyunjin
Partner: UNT Libraries Government Documents Department
open access

Evolution, Interaction, and Intrinsic Properties of Dislocations in Intermetallics: Anisotropic 3D Dislocation Dynamics Approach

Description: The generation, motion, and interaction of dislocations play key roles during the plastic deformation process of crystalline solids. 3D Dislocation Dynamics has been employed as a mesoscale simulation algorithm to investigate the collective and cooperative behavior of dislocations. Most current research on 3D Dislocation Dynamics is based on the solutions available in the framework of classical isotropic elasticity. However, due to some degree of elastic anisotropy in almost all crystalline sol… more
Date: August 18, 2008
Creator: Chen, Qian
Partner: UNT Libraries Government Documents Department
open access

Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

Description: Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence … more
Date: August 15, 2008
Creator: Coble, Inger M
Partner: UNT Libraries Government Documents Department
open access

Measurement of Branching Ratios for Non-leptonic Cabibbo-suppressed Decays of the Charmed-Strange Baryon Xic+

Description: We studied several {Xi}{sub c}{sup +} decay modes, most of them with a hyperon in the final state, and determined their branching ratios. The data used in this analysis come from the fixed target experiment SELEX, a multi-stage spectrometer with high acceptance for forward interactions, that took data during 1996 and 1997 at Fermilab with 600 GeV=c (mainly {Sigma}{sup -}, {pi}{sup -}) and 540 GeV/c (mainly p) beams incident on copper and carbon targets. The thesis mainly details the first obser… more
Date: August 1, 2008
Creator: Vazquez Jauregui, Eric & U., /San Luis Potosi
Partner: UNT Libraries Government Documents Department
open access

Magneto-optical study of the intermediate state in type-I superconductors: Effects of sample shape and applied current

Description: The magnetic flux structures in the intermediate state of bulk, pinning-free Type-I superconductors are studied using a high resolution magneto-optical imaging technique. Unlike most previous studies, this work focuses on the pattern formation of the coexisting normal and superconducting phases in the intermediate state. The influence of various parameters such as sample shape, structure defects (pinning) and applied current are discussed in relation to two distinct topologies: flux tubes (clos… more
Date: August 15, 2008
Creator: Hoberg, Jacob
Partner: UNT Libraries Government Documents Department
open access

Study of correlations between photoproduced pairs of charmed particles at Experiment E831/FOCUS

Description: The authors present the study of the charm-pair correlations produced in photon-nucleon interactions at <E{sub {gamma}}> = 175 GeV/c, by the Fermilab fixed target experiment E831/FOCUS. The E831/FOCUS experiment produced and reconstructed over one million charm particles. This high statistics allows the reconstruction of more than 7000 charm-pair mesons D{bar D}, 10 times the statistic of former experiments, and also allows to get, for the first time, about 600 totally reconstructed charm… more
Date: August 1, 2008
Creator: Castromonte Flores, Cesar Manuel & /Rio de Janeiro, CBPF
Partner: UNT Libraries Government Documents Department
open access

Nonperturbative Dynamics of Strong Interactions from Gauge/Gravity Duality

Description: This thesis studies important dynamical observables of strong interactions such as form factors. It is known that Quantum Chromodynamics (QCD) is a theory which describes strong interactions. For large energies, one can apply perturbative techniques to solve some of the QCD problems. However, for low energies QCD enters into the nonperturbative regime, where different analytical or numerical tools have to be applied to solve problems of strong interactions. The holographic dual model of QCD is … more
Date: August 1, 2008
Creator: Grigoryan, Hovhannes
Partner: UNT Libraries Government Documents Department
open access

Current developments in laser ablation-inductively coupled plasma-mass spectrometry for use in geology, forensics, and nuclear nonproliferation research

Description: This dissertation focused on new applications of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The diverse fields that were investigated show the versatility of the technique. In Chapter 2, LA-ICP-MS was used to investigate the rare earth element (REE) profiles of garnets from the Broken Hill Deposit in New South Wales, Australia. The normalized REE profiles helped to shed new light on the formation of deposits of sulfide ores. This information may be helpful in ident… more
Date: August 26, 2008
Creator: Messerly, Joshua D.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the charged kaon mass with the MIPP RICH

Description: The currently accepted value of the charged kaon mass is 493.677 {+-} 0.013 MeV (26 ppm). It is a weighted average of six measurements, most of which use kaonic atom X-ray energy techniques. The two most recent and precise results dominate the average but differ by 122 ppm. Inconsistency in the data set needs to be resolved, preferably using independent techniques. One possibility uses the Cherenkov effect. A measurement of the charged kaon mass using this technique is presented. The data was t… more
Date: August 1, 2008
Creator: Graf, Nicholas J.
Partner: UNT Libraries Government Documents Department
open access

An Adaptive Landscape Classification Procedure using Geoinformatics and Artificial Neural Networks

Description: The Adaptive Landscape Classification Procedure (ALCP), which links the advanced geospatial analysis capabilities of Geographic Information Systems (GISs) and Artificial Neural Networks (ANNs) and particularly Self-Organizing Maps (SOMs), is proposed as a method for establishing and reducing complex data relationships. Its adaptive and evolutionary capability is evaluated for situations where varying types of data can be combined to address different prediction and/or management needs such as h… more
Date: August 1, 2008
Creator: Coleman, Andre M.
Partner: UNT Libraries Government Documents Department
open access

A Direct Measurement of the $W$ Decay Width

Description: A direct measurement of the W boson total decay width is presented in proton-antiproton collisions at √s = 1.96 TeV using data collected by the CDF II detector. The measurement is made by fitting a simulated signal to the tail of the transverse mass distribution in the electron and muon decay channels. An integrated luminosity of 350 pb<sup>-1</sup> is used, collected between February 2002 and August 2004. Combining the results from the separate decay channels gives the decay width as 2.038 ± 0… more
Date: August 1, 2008
Creator: Vine, Troy
Partner: UNT Libraries Government Documents Department
open access

Shared Spaces: The Human and the Animal in the Works of Zora Neale Hurston, Mark Twain, and Jack London

Description: Living in tune with nature means respecting the natural environment and realizing its power and the ways it manifests in daily life. This essay focuses on the ways in which respect for nature is expressed through animal imagery in Zora Neale Hurston's Their Eyes Were Watching God, Mark Twain's "The Stolen White Elephant," Roughing It, and Pudd'nhead Wilson, and Jack London's The Call of the Wild. Each author encouraged readers to seek the benefits of nature in order to become better human being… more
Date: August 2008
Creator: Harper, Pamela Evans
Partner: UNT Libraries
open access

The Effects of Individualized Test Coaching on Teacher Certification Test Scores.

Description: While student populations are growing, the gatekeeping devices of teacher certification examinations prevent many who want and are trained to teach from entering the profession. If failing these exams predicted failure to teach well, blocking students who do not pass certification exams from entering the profession might be a well-reasoned policy. However, many studies indicate that there is little correlation between certification test scores and quality of teaching. The present study investi… more
Date: August 2008
Creator: Hall, Kathryn Cowart
Partner: UNT Libraries
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