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The use of micellar solutions for novel separation techniques

Description: Surfactant based separation techniques based on the solubilization of organic compounds into the nonpolar interior of a micelle or electrostatic attraction of ionized metals and metal complexes to the charged surface of a micelle were studied in this work. Micellar solutions were used to recover two model volatile organic compounds emitted by the printing and painting industries (toluene and amyl acetate) and to investigate the effect of the most important variables in the surfactant enhanced c… more
Date: December 31, 1993
Creator: Roberts, B. L.
Partner: UNT Libraries Government Documents Department
open access

MagRad: A code to optimize the operation of superconducting magnets in a radiation environment

Description: A powerful computational tool, called MagRad, has been developed which optimizes magnet design for operation in radiation fields. Specifically, MagRad has been used for the analysis and design modification of the cable-in-conduit conductors of the TF magnet systems in fusion reactor designs. Since the TF magnets must operate in a radiation environment which damages the material components of the conductor and degrades their performance, the optimization of conductor design must account not only… more
Date: December 31, 1995
Creator: Yeaw, Christopher T.
Partner: UNT Libraries Government Documents Department
open access

Size-dependent structure of silver nanoparticles under high pressure

Description: Silver noble metal nanoparticles that are<10 nm often possess multiply twinned grains allowing them to adopt shapes and atomic structures not observed in bulk materials. The properties exhibited by particles with multiply twinned polycrystalline structures are often far different from those of single-crystalline particles and from the bulk. I will present experimental evidence that silver nanoparticles<10 nm undergo a reversible structural transformation under hydrostatic pressures up to … more
Date: December 31, 2008
Creator: Koski, Kristie Jo
Partner: UNT Libraries Government Documents Department
open access

Beam Line Design and Beam Physics Study of Energy Recovery Linac Free Electron Laser at Peking University

Description: Energy recovering linac (ERL) offers an attractive alternative for generating intense beams of charged particles by approaching the operational efficiency of a storage ring while maintaining the superior beam quality typical of a linear accelerator. In ERLs, the decelerated beam cancels the beam loading effects of the accelerated beam with high repetition rate. Therefore, ERLs can, in principle, accelerate very high average currents with only modest amounts of RF power. So the efficiency of RF … more
Date: December 31, 2011
Creator: Wang, Guimei
Partner: UNT Libraries Government Documents Department
open access

Towards a Precision Measurement of Parity-Violating e-p Elastic Scattering at Low Momentum Transfer

Description: The goal of the Q-weak experiment is to make a measurement of the proton's weak charge Q{sub W}{sup p} = 1 - 4 sin{sup 2}({theta}{sub W}) to an accuracy of {approx} 4%. This would represent a {approx} 0.3% determination of the weak mixing angle sin{sup 2}({theta}{sub W}) at low energy. The measurement may be used for a precision test of the Standard Model (SM) prediction on the running of sin{sup 2}({theta}{sub W}) with energy scale. The Q-weak experiment operates at Thomas Jefferson National A… more
Date: May 31, 2012
Creator: Pan, Jie
Partner: UNT Libraries Government Documents Department
open access

Delta Electroproduction in 12-C

Description: The Delta-nucleus potential is a crucial element in the understanding of the nuclear system. Previous electroexcitation measurements in the delta region reported a Q2 dependence of the delta mass indicating that this potential is dependent on the momentum of the delta. Such a dependence is not observed for protons and neutrons in the nuclear medium. This thesis presents the experimental study of the electroexcitation of the delta resonance in 12C, performed using the high energy electron beam a… more
Date: January 31, 2003
Creator: McLauchlan, Steven
Partner: UNT Libraries Government Documents Department
open access

Measurement of single spin asymmetry and fifth structure function for the proton(electron vec, electron Kaon+)Lambda reaction with CEBAF Large Acceptance Spectrometer (CLAS)

Description: The single spin asymmetry, A{sub LT} ?, and the polarized structure function, ?{sub LT}?, for the p(e,e?K{sup +})? reaction in the resonance region have been measured and extracted using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Data were taken at an electron beam energy of 2.567 GeV. The large acceptance of CLAS allows for full azimuthal angle coverage over a large range of center-of-mass scattering angles. Results were obtained that span a range in Q{sup 2} from 0.5 to … more
Date: August 31, 2005
Creator: Nasseripour, Rahksha
Partner: UNT Libraries Government Documents Department
open access

Heat Transfer Analysis and Assessment of Kinetics Systems for PBX 9501

Description: The study of thermal decomposition in high explosive (HE) charges has been an ongoing process since the early 1900s. This work is specifically directed towards the analysis of PBX 9501. In the early 1970s, Dwight Jaeger of Los Alamos National Laboratory (LANL) developed a single-step, two-species kinetics system that was used in the development of one of the first finite element codes for thermal analyses known as EXPLO. Jaeger's research focused on unconfined spherical samples of HE charges to… more
Date: July 31, 2006
Creator: Jorenby, Jeffrey W.
Partner: UNT Libraries Government Documents Department
open access

The Effects of Indoleacetic Acid and Kinetin on the Growth of Some Microorganisms

Description: Data are presented from a study of the effects of indoleacetic acid and kinetin on the growth of Amoeba proteus, Escherichia coli, and two species of yeast. Data are tabulated and reaction mechanisms are discussed. 95 references. (C.H.)
Date: March 31, 1959
Creator: Kennell, D.
Partner: UNT Libraries Government Documents Department
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Development of Modeling and Simulation for Magnetic Particle Inspection Using Finite Elements

Description: Magnetic particle inspection (MPI) is a widely used nondestructive inspection method for aerospace applications essentially limited to experiment-based approaches. The analysis of MPI characteristics that affect sensitivity and reliability contributes not only reductions in inspection design cost and time but also improvement of analysis of experimental data. Magnetic particles are easily attracted toward a high magnetic field gradient. Selection of a magnetic field source, which produces a mag… more
Date: May 31, 2003
Creator: Lee, Jun-Youl
Partner: UNT Libraries Government Documents Department
open access

The Zintl Chemistry of the Heavy Tetrel Elements

Description: Exploration of the alkali metal/alkaline-earth metal/heavy tetrel (Sn or Pb) systems has revealed a vast array of new chemistry and novel structure types. The structures and properties of these new materials have been studied in an attempt to understand the chemistry of these and other related systems. The first phase reported is Rb{sub 4}Pb{sub 9} (K{sub 4}Pb{sub 9} type). The compound contains two different types of Pb{sub 9}{sup 4-} deltahedra, a monocapped square pyramid and a distorted tri… more
Date: December 31, 2002
Creator: Corbett, John D.
Partner: UNT Libraries Government Documents Department
open access

High-Throughput Analysis With 96-Capillary Array Electrophoresis and Integrated Sample Preparation for DNA Sequencing Based on Laser Induced Fluorescence Detection

Description: The purpose of this research was to improve the fluorescence detection for the multiplexed capillary array electrophoresis, extend its use beyond the genomic analysis, and to develop an integrated micro-sample preparation system for high-throughput DNA sequencing. The authors first demonstrated multiplexed capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations in a 96-capillary array system with laser-induced fluorescence detection. Migration times of… more
Date: December 31, 2001
Creator: Xue, Gang
Partner: UNT Libraries Government Documents Department
open access

Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

Description: The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-{alpha}-acetamidocinnamate (MAC), has the illustrated structure as established by {sup 31}P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]{sub 4}, [Rh(COD){sub 2}]{sup +}BF{sub 4}{sup -}, [Rh(COD)Cl]{sub 2},… more
Date: May 31, 2003
Creator: Stanger, Keith James
Partner: UNT Libraries Government Documents Department
open access

Scalable Computational Chemistry: New Developments and Applications

Description: The computational part of the thesis is the investigation of titanium chloride (II) as a potential catalyst for the bis-silylation reaction of ethylene with hexaclorodisilane at different levels of theory. Bis-silylation is an important reaction for producing bis(silyl) compounds and new C-Si bonds, which can serve as monomers for silicon containing polymers and silicon carbides. Ab initio calculations on the steps involved in a proposed mechanism are presented. This choice of reactants allows … more
Date: December 31, 2002
Creator: Alexeev, Yuri
Partner: UNT Libraries Government Documents Department
open access

CMOS Interface Circuits for Spin Tunneling Junction Based Magnetic Random Access Memories

Description: Magneto resistive memories (MRAM) are non-volatile memories which use magnetic instead of electrical structures to store data. These memories, apart from being non-volatile, offer a possibility to achieve densities better than DRAMs and speeds faster than SRAMs. MRAMs could potentially replace all computer memory RAM technologies in use today, leading to future applications like instan-on computers and longer battery life for pervasive devices. Such rapid development was made possible due to th… more
Date: December 31, 2002
Creator: Saripalli, Ganesh
Partner: UNT Libraries Government Documents Department
open access

Scanning Tunneling Microscopy Studies of Surface Structures of Icosahedral Al-Cu-Fe Quasicrystals

Description: Three papers are included in this dissertation. The first paper: ''Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED studies'', is in press with ''Surface Science''. The second paper: ''An STM study of the atomic structure of the icosahedral Al-Cu-Fe fivefold surface'' is submitted to ''Physical Review B, Rapid Communication''. The third paper: ''Pseudomorphic starfish: arrangement of extrinsic metal atoms on a quasicrystalline substrate'' is submi… more
Date: December 31, 2002
Creator: Cai, Tanhong
Partner: UNT Libraries Government Documents Department
open access

Laser Micromachining and Information Discovery Using a Dual Beam Interferometry

Description: Lasers have proven to be among the most promising tools for micromachining because they can process features down to the size of the laser wavelength (smaller than 1 micrometer) and they provide a non-contact technology for machining. The demand for incorporating in-situ diagnostics technology into the micromachining environment is driven by the increasing need for producing micro-parts of high quality and accuracy. Laser interferometry can be used as an on-line monitoring tool and it is the ai… more
Date: December 31, 2001
Creator: Theppakuttaikomaraswamy, Senthil P.
Partner: UNT Libraries Government Documents Department
open access

Correlation Between Domain Behavior and Magnetic Properties of Materials

Description: Correlation between length scales in the field of magnetism has long been a topic of intensive study. The long-term desire is simple: to determine one theory that completely describes the magnetic behavior of matter from an individual atomic particle all the way up to large masses of material. One key piece to this puzzle is connecting the behavior of a material's domains on the nanometer scale with the magnetic properties of an entire large sample or device on the centimeter scale. In the firs… more
Date: May 31, 2003
Creator: Leib, Jeffrey Scott
Partner: UNT Libraries Government Documents Department
open access

Nuclear Spin Lattice Relaxation and Conductivity Studies of the Non-Arrhenius Conductivity Behavior in Lithium Fast Ion Conducting Sulfide Glasses

Description: As time progresses, the world is using up more of the planet's natural resources. Without technological advances, the day will eventually arrive when these natural resources will no longer be sufficient to supply all of the energy needs. As a result, society is seeing a push for the development of alternative fuel sources such as wind power, solar power, fuel cells, and etc. These pursuits are even occurring in the state of Iowa with increasing social pressure to incorporate larger percentages … more
Date: May 31, 2003
Creator: Meyer, Benjamin Michael
Partner: UNT Libraries Government Documents Department
open access

Process Optimization for Solid Extraction, Flavor Improvement and Fat Removal in the Production of Soymilk From Full Fat Soy Flakes

Description: Traditionally soymilk has been made with whole soybeans; however, there are other alternative raw ingredients for making soymilk, such as soy flour or full-fat soy flakes. US markets prefer soymilk with little or no beany flavor. modifying the process or using lipoxygenase-free soybeans can be used to achieve this. Unlike the dairy industry, fat reduction in soymilk has been done through formula modification instead of by conventional fat removal (skimming). This project reports the process opt… more
Date: May 31, 2003
Creator: Prawiradjaja, Stanley
Partner: UNT Libraries Government Documents Department
open access

Is Lutein a Physiologically Important Ligand for Transthyretin in Humans?

Description: Lutein and zeaxanthin are the only carotenoids accumulated in the macula of the human retina and are known as the macular pigments (MP). These pigments account for the yellow color of the macula and appear to play an important role in protecting against age-related macular degeneration (AMD). The uptake of lutein and zeaxanthin in human eyes is remarkably specific. It is likely that specific transport or binding proteins are involved. The objective is to determine whether transthyretin (TTR) is… more
Date: May 31, 2003
Creator: Chen, Liwei
Partner: UNT Libraries Government Documents Department
open access

Probabilistic assessment of dynamic system performance. Part 3

Description: Accurate prediction of dynamic system failure behavior can be important for the reliability and risk analyses of nuclear power plants, as well as for their backfitting to satisfy given constraints on overall system reliability, or optimization of system performance. Global analysis of dynamic systems through investigating the variations in the structure of the attractors of the system and the domains of attraction of these attractors as a function of the system parameters is also important for … more
Date: December 31, 1993
Creator: Belhadj, M.
Partner: UNT Libraries Government Documents Department
open access

High Growth Rate Deposition of Hydrogenated Amorphous Silicon-Germanium Films and Devices Using ECR-PECVD

Description: Hydrogenated amorphous silicon germanium films (a-SiGe:H) and devices have been extensively studied because of the tunable band gap for matching the solar spectrum and mature the fabrication techniques. a-SiGe:H thin film solar cells have great potential for commercial manufacture because of very low cost and adaptability to large-scale manufacturing. Although it has been demonstrated that a-SiGe:H thin films and devices with good quality can be produced successfully, some issues regarding grow… more
Date: May 31, 2002
Creator: Liu, Yong
Partner: UNT Libraries Government Documents Department
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