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A Parallel Ocean Model With Adaptive Mesh Refinement Capability For Global Ocean Prediction

Description: An ocean model with adaptive mesh refinement (AMR) capability is presented for simulating ocean circulation on decade time scales. The model closely resembles the LLNL ocean general circulation model with some components incorporated from other well known ocean models when appropriate. Spatial components are discretized using finite differences on a staggered grid where tracer and pressure variables are defined at cell centers and velocities at cell vertices (B-grid). Horizontal motion is model… more
Date: September 8, 2005
Creator: Herrnstein, A
Partner: UNT Libraries Government Documents Department
open access

Ligand Rearrangements of Organometallic Complexes inSolution

Description: Many chemical reactions utilize organometallic complexes as catalysts. These complexes find use in reactions as varied as bond activation, polymerization, and isomerization. This thesis outlines the construction of a new ultrafast laser system with an emphasis on the generation of tunable mid-infrared pulses, data collection, and data analysis.
Date: May 8, 2006
Creator: Shanoski, Jennifer E.
Partner: UNT Libraries Government Documents Department
open access

Kinetics and mechanisms of the reactions of alkyl radicals with oxygen and with complexes of Co(III), Ru(III), and Ni(III)

Description: The kinetics of the reactions of C{sub 2}H{sub 5} radical with Co(NH{sub 3}){sub 5}X{sup 2+}, Ru(NH{sub 3}){sub 5}X{sup 2+}, and Co(dmgH){sub 2} (X) (Y) (X = Br, Cl, N{sub 3}, SCN; Y = H{sub 2}O, CH{sub 3}CN) complexes were studied using laser flash photolysis of ethylcobalt complexes. The kinetics were obtained by the kinetic probe method. Some relative rate constants were also determined by a competition method based on ethyl halide product ratios. The kinetics of colligation reactions of a s… more
Date: October 8, 1990
Creator: Kelley, Douglas
Partner: UNT Libraries Government Documents Department
open access

Application of Ultrasonic Guided Waves to the Characterization of Texture in Metal Sheets of Cubic and Hexagonal Crystallites

Description: Ultrasonic techniques have recently been applied to the texture characterization in polycrystalline aggregates of hexagonal crystals. The basis of this application lies in the relations between the elastic constants {bar C}{sub ij} of the aggregates, which can be inferred from ultrasonic wave velocity measurements, and the orientation distribution coefficients. This communication present such relations for aggregates which possess orthotopic material symmetry and hexagonal crystal symmetry for … more
Date: October 8, 1990
Creator: Li, Yan
Partner: UNT Libraries Government Documents Department
open access

The use of ultraviolet Thomson scattering as a versatile diagnostic for detailed measurements of a collisional laser produced plasma

Description: Collective Thomson scattering from ion-acoustic waves at 266nm is used to obtain spatially resolved, two-dimensional electron density, sound speed, and radial drift profiles of a collisional laser plasma. An ultraviolet diagnostic wavelength minimizes the complicating effects of inverse bremsstrahlung and refractive turning in the coronal region of interest, where the electron densities approach n{sub c}/10. Laser plasmas of this type are important because they model some of the aspects of the … more
Date: January 8, 1993
Creator: Tracy, M. D.
Partner: UNT Libraries Government Documents Department
open access

An investigation of exploitation versus exploration in GBEA optimization of PORS 15 and 16 Problems

Description: It was hypothesized that the variations in time to solution are driven by the competing mechanisms of exploration and exploitation.This thesis explores this hypothesis by examining two contrasting problems that embody the hypothesized tradeoff between exploration and exploitation. Plus one recall store (PORS) is an optimization problem based on the idea of a simple calculator with four buttons: plus, one, store, and recall. Integer addition and store are classified as operations, and one and me… more
Date: May 8, 2012
Creator: Koch, Kaelynn
Partner: UNT Libraries Government Documents Department
open access

Investigation of the relative abundance of heavy versus light nuclei in primary cosmic rays using underground muon bundles

Description: We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth`s surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10{sup 5}TeV. The events are detected using the Soudan 2 experiment`s fine grained tracking calorimeter which is surrounded by a 14 m {times}10 m {times} 31 m proportional tube … more
Date: June 8, 1993
Creator: Sundaralingam, N.
Partner: UNT Libraries Government Documents Department
open access

Rhodium Catalysts in the Oxidation of CO by O<sub>2</sub> and NO: Shape, Composition, and Hot Electron Generation

Description: It is well known that the activity, selectivity, and deactivation behavior of heterogeneous catalysts are strongly affected by a wide variety of parameters, including but not limited to nanoparticle size, shape, composition, support, pretreatment conditions, oxidation state, and electronic state. Enormous effort has been expended in an attempt to understand the role of these factors on catalytic behavior, but much still remains to be discovered. In this work, we have focused on deepening the pr… more
Date: March 8, 2010
Creator: Renzas, James R.
Partner: UNT Libraries Government Documents Department
open access

Software Vulnerability Taxonomy Consolidation

Description: In today's environment, computers and networks are increasing exposed to a number of software vulnerabilities. Information about these vulnerabilities is collected and disseminated via various large publicly available databases such as BugTraq, OSVDB and ICAT. Each of these databases, individually, do not cover all aspects of a vulnerability and lack a standard format among them, making it difficult for end-users to easily compare various vulnerabilities. A central database of vulnerabilities h… more
Date: December 8, 2004
Creator: Polepeddi, S
Partner: UNT Libraries Government Documents Department
open access

NIF facts

Description: The National Ignition Facility (NIF) will use the world's largest laser to compress and heat BB-sized capsules of fusion fuel to thermo-nuclear ignition. NIF experiments will produce temperatures and densities like those in the Sun or in an exploding nuclear weapon. The experiments will help scientists sustain confidence in the nuclear weapon stockpile without nuclear tests as a unique element of the DOE'S Stockpile Stewardship Program and will produce additional benefits in basic science and f… more
Date: September 8, 2000
Creator: Carpenter, J & Warner, B
Partner: UNT Libraries Government Documents Department
open access

Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

Description: This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LF… more
Date: April 8, 2010
Creator: Kramer, K
Partner: UNT Libraries Government Documents Department
open access

Two-axis Beam Steering Mirror Control system for Precision Pointing and Tracking Applications

Description: Precision pointing and tracking of laser beams is critical in numerous military and industrial applications. This is particularly true for systems requiring atmospheric beam propagation. Such systems are plagued by environmental influences which cause the optical signal to break up and wander. Example applications include laser communications, precision targeting, active imaging, chemical remote sensing, and laser vibrometry. The goal of this project is to build a beam steering system using a t… more
Date: February 8, 2006
Creator: Ulander, K
Partner: UNT Libraries Government Documents Department
open access

Exploration of deeply virtual Compton scattering on the neutron in the Hall A of Jefferson Laboratory

Description: Generalized Parton Distributions (GPDs) are universal functions which provide a comprehensive description of hadron properties in terms of quarks and gluons. Deeply Virtual Compton Scattering (DVCS) is the simplest hard exclusive process involving GPDs. In particular, the DVCS on the neutron is mostly sensitive to E, the less constrained GPD, wich allows to access to the quark angular momentum. The first dedicated DVCS experiment on the neutron ran in the Hall A of Jefferson Lab in fall 2004. T… more
Date: December 8, 2006
Creator: Mazouz, Malek
Partner: UNT Libraries Government Documents Department
open access

Lessons from the Past: Possible Courses of Action for the Conflict in Syria

Description: Undergraduate thesis examining the Syrian conflict and the international community's struggle to find an appropriate response. This thesis reviews the conflicts that occurred in Bosnia and Rwanda, the interventions that took place within these states, and how a resolution to these conflicts was created. From this information, the author determines what conflict management strategies had the most success and what types of outside interventions were failures and the similarities of these instance… more
Date: June 8, 2014
Creator: Carter, Rachel
Partner: UNT Honors College
open access

Loss and Texture

Description: Thesis written by a student in the UNT Honors College presented as a series of poems and artistic prints.
Date: August 8, 1994
Creator: Nemec, Nicole L.
Partner: UNT Honors College
open access

Synthesis and characterization of nickel hydroxide powders for battery application

Description: The primary objective of this research was to investigate the synthesis and characterization of Ni(OH){sub 2} powders by homogeneous precipitation. Previous research of the same method showed conflicting results and complete characterization of the particle morphology was not carried out. This study has produced precipitates having a composition of 2Ni(OH){sub 2}{center_dot}Ni(HCO{sub 3}){sub 1.85}(NO{sub 3}){sub 0.15}. The XRD patterns showed peaks commonly observed for {alpha}-Ni(OH){sub 2}. … more
Date: October 8, 1997
Creator: Widjaja, A.
Partner: UNT Libraries Government Documents Department
open access

Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography

Description: Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened… more
Date: October 8, 1997
Creator: Freeze, R.
Partner: UNT Libraries Government Documents Department
open access

Nonlinear response of superconductors to alternating fields and currents

Description: This report discusses the following topics on superconductivity: nonlinearities in hard superconductors such as surface impedance of a type II superconductimg half space and harmonic generation and intermodulation due to alternating transport currents; and nonlinearities in superconducting weak links such as harmonic generation by a long Josephson Junction in a superconducting slab.
Date: October 8, 1997
Creator: McDonald, J.
Partner: UNT Libraries Government Documents Department
open access

Microstructure-strength relationships of heavily deformed magnesium-lithium composites containing steel fibers

Description: The successful development of deformation-processed metal-metal composites (DMMC) offers the potential for ductile, high-strength structural materials with high-temperature stability. An infiltration casting process was used to permeate steel wool preforms with molten magnesium-lithium (Mg-Li) alloys. The selected matrix alloys were hexagonal close packed (HCP) Mg-4wt%Li or body centered cubic (BCC) Mg-12wt%Li; the low carbon steel wool fibers were predominantly BCC ferrite. These cast HCP/BCC … more
Date: October 8, 1997
Creator: Jensen, J.
Partner: UNT Libraries Government Documents Department
open access

Direct methods for dynamic monitoring of secretions from single cells by capillary electrophoresis and microscopy with laser-induced native fluorescence detection

Description: Microscale separation and detection methods for real-time monitoring of dynamic cellular processes (e.g., secretion) by capillary electrophoresis (CE) and microscopic imaging were developed. Ultraviolet laser-induced native fluorescence (LINF) provides simple, sensitive and direct detection of neurotransmitters and proteins without any derivatization. An on-column CE-LINF protocol for quantification of the release from single cell was demonstrated. Quantitative measurements of both the amount o… more
Date: October 8, 1997
Creator: Tong, W.
Partner: UNT Libraries Government Documents Department
open access

Development and application of thin-layer spectroelectrochemical techniques for the study of organosulfur monolayers adsorbed at gold

Description: A main research interest is the characterization of monolayers formed by the spontaneous adsorption of organosulfur compounds at gold. This dissertation describes the development and application of long optical pathlength thin-layer spectroelectrochemistry in an attempt to address key issues regarding the reactivity of surface-immobilized molecules. The first section of this introductory chapter briefly describes the general approach to the preparation and characterization of these films. The l… more
Date: October 8, 1997
Creator: Simmons, N.
Partner: UNT Libraries Government Documents Department
open access

Simulational studies of epitaxial semiconductor superlattices: Quantum dynamical phenomena in ac and dc electric fields

Description: Using high-accuracy numerical methods the author investigates the dynamics of independent electrons in both ideal and realistic superlattices subject to arbitrary ac and/or dc electric fields. For a variety of superlattice potentials, optically excited initial wave packets, and combinations of ac and dc electric fields, he numerically solves the time-dependent Schroedinger equation. In the case of ideal periodic superlattice potentials, he investigates a long list of dynamical phenomena involvi… more
Date: October 8, 1997
Creator: Reynolds, J.
Partner: UNT Libraries Government Documents Department
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