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Fast methods for static Hamilton-Jacobi Partial Differential Equations

Description: The authors develop a family of fast methods approximating the solution to a wide class of static Hamilton-Jacobi partial differential equations. These partial differential equations are considered in the context of control-theoretic and front-propagation problems. In general, to produce a numerical solution to such a problem, one has to solve a large system of coupled non-linear discretized equations. The techniques use partial information about the characteristic directions to de-couple the s… more
Date: May 1, 2001
Creator: Vladimirsky, Alexander Boris
Partner: UNT Libraries Government Documents Department
open access

The Development of Layered Photonic Band Gap Structures Using a Micro-Transfer Molding Technique

Description: Photonic band gap (PBG) crystals are periodic dielectric structures that manipulate electromagnetic radiation in a manner similar to semiconductor devices manipulating electrons. Whereas a semiconductor material exhibits an electronic band gap in which electrons cannot exist, similarly, a photonic crystal containing a photonic band gap does not allow the propagation of specific frequencies of electromagnetic radiation. This phenomenon results from the destructive Bragg diffraction interference … more
Date: May 1, 2001
Creator: Sutherland, Kevin Jerome
Partner: UNT Libraries Government Documents Department
open access

Thermodynamic Critical Field and Superconducting Fluctuation of Vortices for High Temperature Cuprate Superconductor: La-214

Description: Thermodynamics has been studied systematically for the high temperature cuprate superconductor La{sub 2-x}Sr{sub x}CuO{sub 4-{delta}}, La-214, in the entire superconductive region from strongly underdoped to strongly overdoped regimes. Magnetization studies with H{parallel}c have been made in order to investigate the changes in free energy of the system as the number of carriers is reduced. Above the superconducting transition temperature, the normal-state magnetization exhibits a two-dimension… more
Date: May 1, 2001
Creator: Huh, Yung Moo
Partner: UNT Libraries Government Documents Department
open access

Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

Description: Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput s… more
Date: May 1, 2001
Creator: Su, Hui
Partner: UNT Libraries Government Documents Department
open access

High Precision Spectroscopy of Lambda-Hypernuclei by (e, e' K{sup +}) reaction and gamma-ray measurement

Description: Hypernuclei, with one nucleon converted into a hyperon and coupled back to the residual nuclear core, provide a new probe to study the hyperon-nucleon interaction and an additional strangeness degree of freedom to test the limit of our conventional nuclear models in solving the many body system. The First Lambda electroproduction experiment E89009(HNSS) at JLAB focusing on the Lambda hypernuclear spectroscopy in p-shell achieved the best resolution( FWHM: 500-600 keV) ever reached in this field… more
Date: August 1, 2001
Creator: Zhu, Xiaofeng
Partner: UNT Libraries Government Documents Department
open access

Evaluation of chiller modeling approaches and their usability for fault detection

Description: Selecting the model is an important and essential step in model based fault detection and diagnosis (FDD). Several factors must be considered in model evaluation, including accuracy, training data requirements, calibration effort, generality, and computational requirements. All modeling approaches fall somewhere between pure first-principles models, and empirical models. The objective of this study was to evaluate different modeling approaches for their applicability to model based FDD of vapor… more
Date: May 1, 2001
Creator: Sreedharan, Priya
Partner: UNT Libraries Government Documents Department
open access

Drift compression and final focus systems for heavy ion inertial fusion

Description: Longitudinal compression of space-charge dominated beams can be achieved by imposing a head-to-tail velocity tilt on the beam. This tilt has to be carefully tailored, such that it is removed by the longitudinal space-charge repulsion by the time the beam reaches the end of the drift compression section. The transverse focusing lattice should be designed such that all parts of the beam stay approximately matched, while the beam smoothly expands transversely to the larger beam radius needed in th… more
Date: May 1, 2001
Creator: de Hoon, M.J.L.
Partner: UNT Libraries Government Documents Department
open access

The VRFurnace: A Virtual Reality Application for Energy System Data Analysis

Description: This paper presents the Virtual Reality Furnace (VRFurnace) application, an interactive 3-D visualization platform for pulverized coal furnace analysis. The VRFurnace is a versatile toolkit where a variety of different CFD data sets related to pulverized coal furnaces can be studied interactively. The toolkit combines standard CFD analysis techniques with tools that more effectively utilize the 3-D capabilities of a virtual environment. Interaction with data is achieved through a dynamic instru… more
Date: May 1, 2001
Creator: Johnson, Peter Eric
Partner: UNT Libraries Government Documents Department
open access

Geographical and Temporal Dynamics of Chaetocnema Pulicaria Populations and Their Role in Stewart's Disease of Corn in Iowa

Description: This thesis is organized into five chapters. Chapter 1 is the introduction and justification, chapters 2 and 3 are journal papers, chapter 4 is a preliminary analysis of winter environmental variables and their use in forecasting for Stewart's disease of corn, and chapter 5 is general conclusions and discussion. References can be found at the end of each chapter, except chapter 5 and are specific to that chapter.
Date: May 1, 2001
Creator: Esker, Paul David
Partner: UNT Libraries Government Documents Department
open access

Dualities in M-theory and Born-Infeld Theory

Description: We discuss two examples of duality. The first arises in the context of toroidal compactification of the discrete light cone quantization of M-theory. In the presence of nontrivial moduli coming from the M-theory three form, it has been conjectured that the system is described by supersymmetric Yang-Mills gauge theory on a noncommutative torus. We are able to provide evidence for this conjecture, by showing that the dualities of this M-theory compactification, which correspond to T-duality in Ty… more
Date: August 1, 2001
Creator: Brace, Daniel, M
Partner: UNT Libraries Government Documents Department
open access

Numerical Simulation of the Performance Characteristics, Instability, and Effects of Band Gap Grading in Cadmium Telluride Based Photovoltaic Devices

Description: Using computer simulations, the performance of several CdTe based photovoltaic structures has been studied. The advantages and disadvantages of band gap grading, through the use of (Zn,Cd)Te, have also been investigated in these structures. Grading at the front interface between a CdS window layer and a CdTe absorber layer, can arise due to interdiffusion between the materials during growth or due to the intentional variation of the material composition. This grading has been shown to improve c… more
Date: May 1, 2001
Creator: Petersen, Michael David
Partner: UNT Libraries Government Documents Department
open access

Accelerator Mass Spectrometry Measurements of Plutonium in Sediment and Seawater from the Marshall Islands

Description: During the summer 2000, I was given the opportunity to work for about three months as a technical trainee at Lawrence Livermore National Laboratory, or LLNL as I will refer to it hereafter. University of California runs this Department of Energy laboratory, which is located 70 km east of San Francisco, in the small city of Livermore. This master thesis in Radioecology is based on the work I did here. LLNL, as a second U.S.-facility for development of nuclear weapons, was built in Livermore in t… more
Date: August 1, 2001
Creator: Leisvik, M & Hamilton, T
Partner: UNT Libraries Government Documents Department
open access

Focus on NIF May 2001

Description: The National Ignition Facility, a stadium-size, 192-beam laser, is an essential tool for maintaining the safety and reliability of our nuclear weapons, harnessing fusion energy for future generations, and unlocking the origins of the universe. In the FY2001 Energy and Water Appropriations Act (FPN00-48), Congress appropriated $199.1 million for the continued construction of NIF. Immediately, $130 million became available. After March 31, 2001, $69.1 million was to be made available only after D… more
Date: May 1, 2001
Creator: Warner, B
Partner: UNT Libraries Government Documents Department
open access

Inertial Confinement Fusion Annual Report 1999

Description: The ICF Program has undergone a significant change in 1999 with the decommissioning of the Nova laser and the transfer of much of the experimental program to the OMEGA laser at the University of Rochester. The Nova laser ended operations with the final experiment conducted on May 27, 1999. This marked the end to one of DOE's most successful experimental facilities. Since its commissioning in 1985, Nova performed 13,424 experiments supporting ICF, Defense Sciences, high-power laser research, and… more
Date: July 1, 2001
Creator: Kauffman, R.
Partner: UNT Libraries Government Documents Department
open access

Collisionless relaxation in beam-plasma systems

Description: This thesis reports the results from the theoretical investigations, both numerical and analytical, of collisionless relaxation phenomena in beam-plasma systems. Many results of this work can also be applied to other lossless systems of plasma physics, beam physics and astrophysics. Different aspects of the physics of collisionless relaxation and its modeling are addressed. A new theoretical framework, named Coupled Moment Equations (CME), is derived and used in numerical and analytical studies… more
Date: May 1, 2001
Creator: Backhaus, Ekaterina Yu.
Partner: UNT Libraries Government Documents Department
open access

Mechanics of Metals with Phase Changes

Description: New experimental data is presented on some exotic metals that exhibit phase changes at cryogenic temperatures. The types of phase changes that were detected in the specific heat data range from martensitic (diffusion less) transitions to superconducting transitions. In addition, the charge density wave (CDW) state in uranium metal was detected in the specific heat. Specific-heat measurements were made in zero-magnetic field using an apparatus capable of obtaining temperatures as low as 0.4 K. C… more
Date: January 1, 2001
Creator: Lashley, J.C.
Partner: UNT Libraries Government Documents Department
open access

The Influence of Ergonomics Training on Employee Behavior at Los Alamos National Laboratory

Description: A survey of employee behavior was conducted at Los Alamos National Laboratory (LANL). The objective of this study was to evaluate the prevalence of ergonomic behavior that decreased the chance of having a work-related musculoskeletal disorder (WMSD) among employees. The null hypothesis was tested to determine if there was a significant difference in ergonomic behavior between trained and untrained employees. The LANL employees were stratified by job series and then randomly selected to particip… more
Date: January 1, 2001
Creator: Puckett, Leslie Guthrie
Partner: UNT Libraries Government Documents Department
open access

Properties of Group Five and Group Seven transactinium elements

Description: The detection and positive identification of the short-lived, low cross section isotopes used in the chemical studies of the heaviest elements are usually accomplished by measuring their alpha-decay, thus the nuclear properties of the heaviest elements must be examined simultaneously with their chemical properties. The isotopes 224 Pa and 266,267 Bh have been studied extensively as an integral part of the investigation of the heaviest members of the groups five and seven of the periodic table. … more
Date: May 1, 2001
Creator: Wilk, Philip A.
Partner: UNT Libraries Government Documents Department
open access

Pump probe spectroscopy of quasiparticle dynamics in cuprate superconductors

Description: Pump probe spectroscopy is used to examine the picosecond response of a BSCCO thin film, and two YBCO crystals in the near infrared. The role of pump fluence and temperature have been closely examined in an effort to clarify the mechanism by which the quasiparticles rejoin the condensate. BSCCO results suggest that the recombination behavior is consistent with the d-wave density of states in that quasiparticles appear to relax to the nodes immediately before they rejoin the condensate. The firs… more
Date: May 1, 2001
Creator: Segre, Gino P.
Partner: UNT Libraries Government Documents Department
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