13 Matching Results

Search Results

Results: 1 - 13
open access

Straddle-packer determination of the vertical distribution of hydraulic properties in the Snake River Plain Aquifer at well USGS-44, Idaho Chemical Processing Plant, INEL

Description: Many of the monitor wells that penetrate the upper portion of the Snake River Plain aquifer at the Idaho National Engineering Laboratory (INEL) are open over large intervals that include multiple water-bearing zones. Most of these wells are equipped with dedicated submersible pumps. Water of varying quality from different water-bearing zones is mixed within the wells. The hydrologic properties of individual water bearing zones are difficult to determine. Water quality and water-level data on or… more
Date: September 23, 1994
Creator: Monks, J. I.
Partner: UNT Libraries Government Documents Department
open access

Quantum harmonic Brownian motion in a general environment: A modified phase-space approach

Description: After extensive investigations over three decades, the linear-coupling model and its equivalents have become the standard microscopic models for quantum harmonic Brownian motion, in which a harmonically bound Brownian particle is coupled to a quantum dissipative heat bath of general type modeled by infinitely many harmonic oscillators. The dynamics of these models have been studied by many authors using the quantum Langevin equation, the path-integral approach, quasi-probability distribution fu… more
Date: June 23, 1993
Creator: Yeh, L.
Partner: UNT Libraries Government Documents Department
open access

The North American Indians and the Establishment of European Empires 1519-1676

Description: Thesis written by a student in the UNT Honors College discussing the rise of Spanish, English, and French colonialism in the Americas, the conflicts that arose with the native populations, and alliances between the colonists and various tribes.
Date: March 23, 1996
Creator: Lovette, John
Partner: UNT Honors College
open access

New methods and materials for solid phase extraction and high performance liquid chromatography

Description: This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.
Date: April 23, 1996
Creator: Dumont, P.J.
Partner: UNT Libraries Government Documents Department
open access

Photodissociation dynamics of polyatomic molecules

Description: This report consists of five studies as follows: A laser photofragmentation time-of-flight mass spectrometric study of acetophenone at 193 and 248 nm; A 193 nm laser photofragmentation time-of-flight mass spectrometric study of dimethylsulfoxide; 193 nm laser photofragmentation time-of-flight mass spectrometric study of HSCH{sub 2}CH{sub 2}SH; Thiophene biradical decay of the primary laser photofragmentation product at 193 nm; and Scattering cross sections for O({sup 3}P)[SO(X,{sup 3}{Sigma}{su… more
Date: February 23, 1998
Creator: Zhao, H.
Partner: UNT Libraries Government Documents Department
open access

Synthesis and characterization of novel group VI metal (Mo, W) nitride and oxide compounds

Description: Investigations into the preparation of tungsten nitrides have involved the synthesis of molecular precursors, and their conversion to tungsten nitrides at relatively low temperatures. Two interesting molecular precursors, [WNCl{sub 3}{center_dot}NCCH{sub 3}]{sub 4} and WN(N{sub 3}){sub 3}{center_dot}xNCCH{sub 3}, have been prepared and characterized. The molecular structure of the first consists of a W{sub 4}N{sub 4} tetrameric core with multiple and single W-N bonds arranged in an alternating … more
Date: February 23, 1998
Creator: Zhang, Z.
Partner: UNT Libraries Government Documents Department
open access

Neutron scattering studies of the RENi{sub 2}B{sub 2}C (RE = Lu, Y, Ho, Er): Lattice dynamics

Description: The first chapter gives a brief overview of the system discussed in this dissertation. Chapters 2--5 and Appendix B of this dissertation consist of papers that are published, or have been submitted, which show experimental data regarding the phonon softening of LuNi{sub 2}B{sub 2}C. These papers have been removed and processed separately. Chapter 6 will contain a summary of the conclusions up to date. Appendix A will consist of a brief derivation of {chi}(q) which is talked about in the introdu… more
Date: February 23, 1998
Creator: Bullock, M.
Partner: UNT Libraries Government Documents Department
open access

Interfacial characterization and analytical applications of chemically-modified surfaces

Description: The goal of this work is to explore several new strategies and approaches to the surface modification and the microscopic characterization of interfaces in the areas mainly targeting sensor technologies that are of interest to environmental control or monitoring, and scanning probe microscopies techniques that can monitor interfacial chemical reactions in real time. Centered on the main theme, four specific topics are presented as four chapters in this dissertation following the general introdu… more
Date: February 23, 1998
Creator: Wang, J.
Partner: UNT Libraries Government Documents Department
open access

Quantum groups, roots of unity and particles on quantized Anti-de Sitter space

Description: Quantum groups in general and the quantum Anti-de Sitter group U{sub q}(so(2,3)) in particular are studied from the point of view of quantum field theory. The author shows that if q is a suitable root of unity, there exist finite-dimensional, unitary representations corresponding to essentially all the classical one-particle representations with (half) integer spin, with the same structure at low energies as in the classical case. In the massless case for spin {ge} 1, {open_quotes}naive{close_q… more
Date: May 23, 1997
Creator: Steinacker, H.
Partner: UNT Libraries Government Documents Department
open access

The structure-property relationships of powder processed Fe-Al-Si alloys

Description: Iron-aluminum alloys have been extensively evaluated as semi-continuous product such as sheet and bar, but have not been evaluated by net shape P/M processing techniques such as metal injection molding. The alloy compositions of iron-aluminum alloys have been optimized for room temperature ductility, but have limited high temperature strength. Hot extruded powder alloys in the Fe-Al-Si system have developed impressive mechanical properties, but the effects of sintering on mechanical properties … more
Date: February 23, 1998
Creator: Prichard, P.D.
Partner: UNT Libraries Government Documents Department
open access

Solidification process in melt spun Nd-Fe-B type magnets

Description: A generalized solidification model has been developed based on a systematic investigation on the microstructure of melt spun Nd-Fe-B alloys. Melt spinning was conducted on initial stoichiometric and TiC added Nd{sub 2}Fe{sub 14}B (2-14-1) compositions to produce under, optimally and over quenched microstructures. Microstructural characterization was carried out by TEM, SEM, Optical microscopy, XRD, DTA, VSM and DC SQUID techniques. By taking the dendritic breakup during recalescence into consid… more
Date: February 23, 1998
Creator: Li, C.
Partner: UNT Libraries Government Documents Department
open access

Solidification analysis of a centrifugal atomizer using the Al-32.7wt.% Cu alloy

Description: A centrifugal atomizer (spinning disk variety) was designed and constructed for the production of spherical metal powders, 100--1,000 microns in diameter in an inert atmosphere. Initial atomization experiments revealed the need for a better understanding of how the liquid metal was atomized and how the liquid droplets solidified. To investigate particle atomization, Ag was atomized in air and the process recorded on high-speed film. To investigate particle solidification, Al-32.7 wt.% Cu was at… more
Date: February 23, 1998
Creator: Osborne, M.G.
Partner: UNT Libraries Government Documents Department
open access

Stability of eutectic interface during directional solidification

Description: Directional solidification of eutectic alloys shows different types of eutectic morphologies. These include lamellar, rod, oscillating and tilting modes. The growth of these morphologies occurs with a macroscopically planar interface. However, under certain conditions, the planar eutectic front becomes unstable and gives rise to a cellular or a dendritic structure. This instability leads to the cellular/dendritic structure of either a primary phase or a two-phase structure. The objective of thi… more
Date: April 23, 1996
Creator: Han, S.H.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen