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A Visual Study of Folk Art Death Imagery Used During the Day of the Dead Celebration in Mexico (open access)

A Visual Study of Folk Art Death Imagery Used During the Day of the Dead Celebration in Mexico

This paper discusses the author's work creating five collagraph prints based on imagery used during the Mexican Day of the Dead celebration and the process of making these prints. Eduardo J. Garcia discusses how heritage impacted these works and explores the meaning behind the folk art imagery.
Date: December 1994
Creator: Garcia, Eduardo J.
System: The UNT Digital Library
Depth migration in transversely isotropic media with explicit operators (open access)

Depth migration in transversely isotropic media with explicit operators

The author presents and analyzes three approaches to calculating explicit two-dimensional (2D) depth-extrapolation filters for all propagation modes (P, SV, and SH) in transversely isotropic media with vertical and tilted axis of symmetry. These extrapolation filters are used to do 2D poststack depth migration, and also, just as for isotropic media, these 2D filters are used in the McClellan transformation to do poststack 3D depth migration. Furthermore, the same explicit filters can also be used to do depth-extrapolation of prestack data. The explicit filters are derived by generalizations of three different approaches: the modified Taylor series, least-squares, and minimax methods initially developed for isotropic media. The examples here show that the least-squares and minimax methods produce filters with accurate extrapolation (measured in the ability to position steep reflectors) for a wider range of propagation angles than that obtained using the modified Taylor series method. However, for low propagation angles, the modified Taylor series method has smaller amplitude and phase errors than those produced by the least-squares and minimax methods. These results suggest that to get accurate amplitude estimation, modified Taylor series filters would be somewhat preferred in areas with low dips. In areas with larger dips, the least-squares and minimax …
Date: December 1994
Creator: Uzcategui, O.
System: The UNT Digital Library
Further studies of the effects of oxidation on the surface properties of coal and coal pyrite (open access)

Further studies of the effects of oxidation on the surface properties of coal and coal pyrite

The objective of this research was to investigate the oxidation behavior of coal and coal pyrite and to correlate the changes in the surface properties induced by oxidation, along with the intrinsic physical and chemical properties of these organic and inorganic materials, with the behavior in physical coal cleaning processes. This provide more fundamental knowledge for understanding the way in which different factors interact in a medium as heterogeneous as coal. Fourteen coal samples of different ranks ranging from high to medium sulfur content were studied by dry oxidation tests at different temperatures and humidities, and by wet oxidation tests using different oxidizing agents. The concentration of surface oxygen functional groups was determined by ion-exchange methods. The changes in the coal composition with oxidation were analyzed by spectroscopic techniques. The wettability of as-received and oxidized coal and coal pyrite samples was assessed by film flotation tests. The electrokinetic behavior of different coals and coal pyrite samples was studied by electrokinetic tests using electrophoresis. Possible oxidation mechanisms have been proposed to explain the changes on the coal surface induced by different oxidation treatments.
Date: December 31, 1994
Creator: Herrera, Miguel Nicholas
System: The UNT Digital Library
Vibrational spectroscopy of water interfaces (open access)

Vibrational spectroscopy of water interfaces

The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful and versatile tools for studying all kinds of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the second order nonlinear susceptibility. The technique of infrared-visible sum frequency generation (SFG) is particularly attractive because it offers a viable way to do vibrational spectroscopy on any surfaces accessible to light with submonolayer sensitivity. In this thesis, the author applies SFG to study a number of important water interfaces. At the air/water interface, hydrophobic solid/water and liquid/water interfaces, it was found that approximately 25% of surface water molecules have one of their hydrogen pointing away from the liquid water. The large number of unsatisfied hydrogen bonds contributes significantly to the large interfacial energy of the hydrophobic surfaces. At the hydrophilic fused quartz/water interface and a fatty acid monolayer covered water surface, the structure and orientation of surface water molecules are controlled by the hydrogen bonding of water molecules with the surface OH groups and the electrostatic interaction with the surface field from the ionization of surface groups. A change of pH value in the bulk water can significantly change the relative importance of …
Date: December 1, 1994
Creator: Du, Q.
System: The UNT Digital Library
Jasmine's Secret: Narrative Cantata for Five Solo Voices, Narrator, and Orchestra (open access)

Jasmine's Secret: Narrative Cantata for Five Solo Voices, Narrator, and Orchestra

Since Jasmine's Secret contains elements of cantata and follows a dramatic story or program, the work may be classified as a narrative or dramatic story or program, the work may be classified as a narrative or dramatic cantata employing five solo voices, narrator and orchestra. This work attempts a revival of these two genres as a combined entity due to the decreased popularity of both cantata and programmatic music in the 20th century.
Date: December 1994
Creator: Alley, Candace P.
System: The UNT Digital Library
Trained Musical Performers' and Musically Untrained College Students' Ability to Discriminate Music Instrument Timbre as a Function of Duration (open access)

Trained Musical Performers' and Musically Untrained College Students' Ability to Discriminate Music Instrument Timbre as a Function of Duration

The purpose of this study was to investigate the ability of trained musicians and musically untrained college students to discriminate music instrument timbre as a function of duration. Specific factors investigated were the thresholds for timbre discrimination as a function of duration, musical ensemble participation as training, and the relative discrimination abilities of vocalists and instrumentalists. Under the conditions of this study, it can be concluded that the threshold for timbre discrimination as a function of duration is at or below 20 ms. Even though trained musicians tended to discriminate timbre better than musically untrained college students, musicians cannot discriminate timbre significantly better then those subjects who have not participated in musical ensembles. Additionally, instrumentalists tended to discriminate timbre better than vocalists, but the discrimination is not significantly different. Recommendations for further research include suggestions for a timbre discrimination measurement tool that takes into consideration the multidimensionality of timbre and the relationship of timbre discrimination to timbre source, duration, pitch, and loudness.
Date: December 1994
Creator: Johnston, Dennis A. (Dennis Alan)
System: The UNT Digital Library
Methods and Meditations upon Portraiture: Inside Out (open access)

Methods and Meditations upon Portraiture: Inside Out

In this proposed study, I had hoped to discover new strategies to develop imagery. I also wanted to know if using strategies in my work that expressed the psyche of myself, would work to express the psyche of other people. By using new and old strategies, I wanted to see not only if the outside face of people in photographs could be misread but if the inside face of people could be expressed.
Date: December 1994
Creator: Lee-Miller, Peggy
System: The UNT Digital Library
Breakdown (open access)

Breakdown

Breakdown is a 17 minute, single movement work for orchestra in five sections. It is scored for 2 flutes, 2 oboes, 2 Bb clarinets, 2 bassoons, 3 Bb trumpets, 4 horns in F, 3 trombones, tuba, percussion, piano, and strings. The percussion consists of a tam-tam, 5 break drums, 4 timbales, 2 gourds, chimes, marimba, vibraphone, snare drum, 2 field drums, bass drum and tympani. The inspiration for this work is the poetry of Bruce Weigl which deals with many facets of the Vietnam experience. One particular work from his collection Song of Napalm, the poem "Breakdown", provided the basis for the emotional and structural content of the music. There are two primary sources of pitch material in the music of Breakdown, both of which have links to the Vietnam War. The name of a soldier who was killed in Vietnam, Miles Cooper, was used to generate a basic pitch set and a series of variation sets that provide much of the harmonic and melodic material in Breakdown. There derived sets are supported by the use of phrases and motives from the hymn Jewels, which celebrates the love of God for his children, and providesan indirect link to the subject …
Date: December 1994
Creator: Kappaz, Philip C., 1956-
System: The UNT Digital Library
The Soul of it: A Video Documentary on Texas Sculptor John Thomas Campbell (open access)

The Soul of it: A Video Documentary on Texas Sculptor John Thomas Campbell

This thesis includes a video and a production report . The video documents a Denton artist, John Thomas Campbell who was working on a project for the Texas State Fair during the filming period. This documentary follows Campbell through his production on sculptures, using a biographical style to explore his life and his art work. The accompanying paper reports on the production background, pre-production process, and includes discussion of the problems encountered from production through post production stages.
Date: December 1994
Creator: Chou, Wei-Tung
System: The UNT Digital Library
Trade Negotiations in Agriculture: A Comparative Study of the U.S. and the EC (open access)

Trade Negotiations in Agriculture: A Comparative Study of the U.S. and the EC

This study applies Destler's institutional counterweights to Putnam's two-level analysis, substituting Liberal Institutionalism and Realism for internationalism and isolationism, in a comparative case study of the roles played by the U.S. and the EC in multilateral trade negotiations in agriculture under the aegis of the General Agreement for Tariffs and Trade during the first half of the Uruguay Round. Using game theory as an analytical tool in the process, this present study demonstrates that a clear pattern emerges in which stages of cooperation and deadlock can be easily anticipated in games of Chicken and Prisoners' Dilemma in accordance with various but predictable levels of institutional influence.
Date: December 1994
Creator: Gordon, H. William (Harold William)
System: The UNT Digital Library
Comparisons of Self-Perceptions in Boys With Attention-Deficit Hyperactivity Disorder, Learning Disabilities, and Non-Referred Boys (open access)

Comparisons of Self-Perceptions in Boys With Attention-Deficit Hyperactivity Disorder, Learning Disabilities, and Non-Referred Boys

A limited amount of research exists that addresses low self-esteem, poor self-concept, and distorted self-image in children with Attention-deficit Hyperactivity Disorder (ADHD). The most urgent task is to test assumptions regarding self-perception and to assess the dimensions of self-concept influenced by this disorder. The Self-Perception Profile for Children (Harter, 1985) was used in the present study to assess those dimensions. Participants included 34 boys with ADHD, 27 boys with LD, and 33 boys without any diagnosed psychological or learning problems. Results were analyzed using Pearson's product-moment correlation, analyses of variance (ANOVA), and analyses of covariance (ANCOVA) and did not support the hypotheses.
Date: December 1994
Creator: Walters, Jill Anne, 1965-
System: The UNT Digital Library
Differential geometry on Hopf algebras and quantum groups (open access)

Differential geometry on Hopf algebras and quantum groups

The differential geometry on a Hopf algebra is constructed, by using the basic axioms of Hopf algebras and noncommutative differential geometry. The space of generalized derivations on a Hopf algebra of functions is presented via the smash product, and used to define and discuss quantum Lie algebras and their properties. The Cartan calculus of the exterior derivative, Lie derivative, and inner derivation is found for both the universal and general differential calculi of an arbitrary Hopf algebra, and, by restricting to the quasitriangular case and using the numerical R-matrix formalism, the aforementioned structures for quantum groups are determined.
Date: December 15, 1994
Creator: Watts, P.
System: The UNT Digital Library
Semiclassical methods in chemical reaction dynamics (open access)

Semiclassical methods in chemical reaction dynamics

Semiclassical approximations, simple as well as rigorous, are formulated in order to be able to describe gas phase chemical reactions in large systems. We formulate a simple but accurate semiclassical model for incorporating multidimensional tunneling in classical trajectory simulations. This model is based on the existence of locally conserved actions around the saddle point region on a multidimensional potential energy surface. Using classical perturbation theory and monitoring the imaginary action as a function of time along a classical trajectory we calculate state-specific unimolecular decay rates for a model two dimensional potential with coupling. Results are in good comparison with exact quantum results for the potential over a wide range of coupling constants. We propose a new semiclassical hybrid method to calculate state-to-state S-matrix elements for bimolecular reactive scattering. The accuracy of the Van Vleck-Gutzwiller propagator and the short time dynamics of the system make this method self-consistent and accurate. We also go beyond the stationary phase approximation by doing the resulting integrals exactly (numerically). As a result, classically forbidden probabilties are calculated with purely real time classical trajectories within this approach. Application to the one dimensional Eckart barrier demonstrates the accuracy of this approach. Successful application of the semiclassical hybrid …
Date: December 1, 1994
Creator: Keshavamurthy, S.
System: The UNT Digital Library
Quasiparticle energy studies of bulk semiconductors, surfaces and nanotubes (open access)

Quasiparticle energy studies of bulk semiconductors, surfaces and nanotubes

Effects of many-body effects on electronic excitation energies (quasiparticle band structure) of these materials are explored. GW approximation, including local field effects, for self-energy operator is used to calculate quasi-particle energies. The newly discovered carbon nanotubes are studied; structural stability and band structures are calculated. BN nanotubes are also studied, and their stability is predicted. Unexpected electronic features are predicted for both systems. Filling of carbon nanotubes with metal atoms and the doping of BN nanotubes by carbon and other impurites is also studied. The occupied surface states at H/Si(111)-(1{times}1) surface are studied; it is shown that the electronic structure requires a full quasiparticle calculation even for this simple chemisorption system. The core level shift of the Si 2p levels for atoms near the H/Si(111)-(1{times}1) surface is calculated; a simple first order perturbation theory using pseudopotential and the local density approximation gives good results for the photoemission spectra of the core electrons. The quasiparticle energies of bulk hexagonal BN and those of an isolated BN sheet are studied; this provides an understanding of the quasiparticle band structure of BN nanotubes. A nearly free electron state with a wavefunction in the interlayer or vacuum region composes the bottom of the conduction …
Date: December 1, 1994
Creator: Blase, X.F.
System: The UNT Digital Library
An object-oriented extension for debugging the virtual machine (open access)

An object-oriented extension for debugging the virtual machine

A computer is nothing more then a virtual machine programmed by source code to perform a task. The program`s source code expresses abstract constructs which are compiled into some lower level target language. When a virtual machine breaks, it can be very difficult to debug because typical debuggers provide only low-level target implementation information to the software engineer. We believe that the debugging task can be simplified by introducing aspects of the abstract design and data into the source code. We introduce OODIE, an object-oriented extension to programming languages that allows programmers to specify a virtual environment by describing the meaning of the design and data of a virtual machine. This specification is translated into symbolic information such that an augmented debugger can present engineers with a programmable debugging environment specifically tailored for the virtual machine that is to be debugged.
Date: December 1, 1994
Creator: Pizzi, R.G. Jr.
System: The UNT Digital Library
Three Dimensional Nuclear Magnetic Resonance Spectroscopic Imaging of Sodium Ions Using Stochastic Excitation and Oscillating Gradients (open access)

Three Dimensional Nuclear Magnetic Resonance Spectroscopic Imaging of Sodium Ions Using Stochastic Excitation and Oscillating Gradients

Nuclear magnetic resonance (NMR) spectroscopic imaging of {sup 23}Na holds promise as a non-invasive method of mapping Na{sup +} distributions, and for differentiating pools of Na{sup +} ions in biological tissues. However, due to NMR relaxation properties of {sup 23}Na in vivo, a large fraction of Na{sup +} is not visible with conventional NMR imaging methods. An alternate imaging method, based on stochastic excitation and oscillating gradients, has been developed which is well adapted to measuring nuclei with short T{sub 2}. Contemporary NMR imaging techniques have dead times of up to several hundred microseconds between excitation and sampling, comparable to the shortest in vivo {sup 23}Na T{sub 2} values, causing significant signal loss. An imaging strategy based on stochastic excitation has been developed which greatly reduces experiment dead time by reducing peak radiofrequency (RF) excitation power and using a novel RF circuit to speed probe recovery. Continuously oscillating gradients are used to eliminate transient eddy currents. Stochastic {sup 1}H and {sup 23}Na spectroscopic imaging experiments have been performed on a small animal system with dead times as low as 25{mu}s, permitting spectroscopic imaging with 100% visibility in vivo. As an additional benefit, the encoding time for a 32x32x32 spectroscopic image …
Date: December 1, 1994
Creator: Frederick, B. deB.
System: The UNT Digital Library
The use of energy management and control systems to monitor the energy performance of commercial buildings (open access)

The use of energy management and control systems to monitor the energy performance of commercial buildings

Monitored data play a very important part in the implementation and evaluation of energy conservation technologies and programs. However, these data can be expensive to collect, so there is a need for lower-cost alternatives. In many situations, using the computerized Energy Management and Control Systems (EMCSs)--already installed in many buildings--to collect these commercial building performance data has advantages over more conventional methods. This method provides data without installing incremental hardware, and the large amounts of available operational data can be a very rich resource for understanding building performance. This dissertation addresses several of these issues. One specific objective is to describe a monitoring-project planning process that includes definition of objectives, constraints, resources and approaches for the monitoring. The choice of tools is an important part of this process. The dissertation goes on to demonstrate, through eight case studies, that EMCS monitoring is possible, and to identify and categorize the problems and issues that can be encountered. These issues lead to the creation, use, and testing of a set of methods for evaluation of EMCS monitoring, in the form of guidelines. Finally, EMCS monitoring is demonstrated and compared with conventional monitoring more methodically in a detailed case study.
Date: December 1, 1994
Creator: Heinemeier, K.E.
System: The UNT Digital Library
Structural influences on the work hardening behavior of aluminum (open access)

Structural influences on the work hardening behavior of aluminum

Effects of various grain and subgrain morphologies on low temperature work hardening of pure Al is studied using tensile tests. Plotting the work hardening rate as a function of true stress, the work hardening is separable into two distinct regimes. Both regimes are approximated by a line {Theta} = {Theta}{sub 0} {minus} K{sub 2}{sigma}, where {Theta}{sub 0} is theoretical work hardening rate at zero stress and K{sub 2} is related to dynamic recovery rate. The first or early deformation regime exhibits greater values of {Theta}{sub 0} and K{sub 2} and can extend up to the first 10% strain of tensile deformation. This early deformation regime is contingent on the existence of a pre-existent dislocation substructure from previous straining. The {Theta}{sub 0} and K{sub 2} associated with the early deformation regime are dependent on the strength and orientation of the pre-existent dislocation substructure relative to the new strain path. At high enough temperatures, this pre-existent dislocation substructure is annealed out, resulting in the near elimination of the early deformation regime. In comparison, the latter regime is dominated by the initial grain and/or subgrain morphology and exhibit lower values of {Theta}{sub 0} and K{sub 2}. The actual value of K{sub 2} in …
Date: December 1, 1994
Creator: Chu, D.
System: The UNT Digital Library
Advanced far infrared detector and double donor studies in Ge (open access)

Advanced far infrared detector and double donor studies in Ge

This has application to astronomy and astrophysics. Selenium in Ge has been studied with a doping technique which limits complex formation. Only one ionization level has been found to correspond to selenium, which presumably occupies a substitutional site. This level is extremely unstable and its concentration decreases after annealing at 400C. Future work is planned to anneal the fast neutron damage before much selenium has formed in the {sup 74/76}Ge samples. It is expected that the observed selenium level can be better characterized and the missing selenium level is more likely to be discovered if other defects are removed before {sup 77}Se formation.
Date: December 1, 1994
Creator: Olsen, C.S.
System: The UNT Digital Library
Plasma destruction of North Carolina`s hazardous waste based on hazardous waste generated between the years of 1989 and 1992 (open access)

Plasma destruction of North Carolina`s hazardous waste based on hazardous waste generated between the years of 1989 and 1992

The purpose of this research is to analyze the applicability of the plasma waste destruction technology to North Carolina hazardous waste streams. This study outlines the current regulations, existing technologies, and innovative technologies being considered as hazardous waste treatment alternatives. From this foundation, the study proceeds to identify the superiority of the plasma waste destruction technology. Specific areas of discussion include: temperature capabilities, waste residence time requirements, destruction removal efficiencies, operational efficiencies, economic issues, safety, and maintenance. This study finds the plasma destruction technology to be fully effective and superior to conventional facilities. The technology completely destroys hydrocarbons and can reduce the volume of many other hazardous wastes on the order of one part per million. The required residence time of waste in a plasma facility for effective destruction is a fraction of a second, while the rotary kiln incinerator maintains an average residence time of approximately 5 seconds. Also mass and heat balance calculations are performed to quantify the effectiveness and efficiency of this technology. It is found that one day`s average amount of hazardous waste generated in the state of North Carolina can be destroyed in approximately thirty seconds using a standard one megawatt power source. Yet, before …
Date: December 31, 1994
Creator: Williams, D.L.
System: The UNT Digital Library
{sup 222}Rn in water: A comparison of two sample collection methods and two sample transport methods, and the determination of temporal variation in North Carolina ground water (open access)

{sup 222}Rn in water: A comparison of two sample collection methods and two sample transport methods, and the determination of temporal variation in North Carolina ground water

Objectives of this field experiment were: (1) determine whether there was a statistically significant difference between the radon concentrations of samples collected by EPA`s standard method, using a syringe, and an alternative, slow-flow method; (2) determine whether there was a statistically significant difference between the measured radon concentrations of samples mailed vs samples not mailed; and (3) determine whether there was a temporal variation of water radon concentration over a 7-month period. The field experiment was conducted at 9 sites, 5 private wells, and 4 public wells, at various locations in North Carolina. Results showed that a syringe is not necessary for sample collection, there was generally no significant radon loss due to mailing samples, and there was statistically significant evidence of temporal variations in water radon concentrations.
Date: December 31, 1994
Creator: Hightower, J. H., III
System: The UNT Digital Library
Modeling the effects of atmospheric emissions on groundwater composition (open access)

Modeling the effects of atmospheric emissions on groundwater composition

A composite model of atmospheric, unsaturated and groundwater transport is developed to evaluate the processes determining the distribution of atmospherically derived contaminants in groundwater systems and to test the sensitivity of simulated contaminant concentrations to input parameters and model linkages. One application is to screen specific atmospheric emissions for their potential in determining groundwater age. Temporal changes in atmospheric emissions could provide a recognizable pattern in the groundwater system. The model also provides a way for quantifying the significance of uncertainties in the tracer source term and transport parameters on the contaminant distribution in the groundwater system, an essential step in using the distribution of contaminants from local, point source atmospheric emissions to examine conceptual models of groundwater flow and transport.
Date: December 31, 1994
Creator: Brown, T. J.
System: The UNT Digital Library
Reconciling uncertainties in integrated science and policy models: Applications to global climate change (open access)

Reconciling uncertainties in integrated science and policy models: Applications to global climate change

In this thesis tools of data reconciliation are used to integrate available information into scientific and policy models of greenhouse gases. The role of uncertainties in scientific and policy models of global climate change is examined, and implications for global change policy are drawn. Methane is the second most important greenhouse gas. Global sources and sinks of methane have significant uncertainties. A chance constrained methodology was developed and used to perform inversions on the global methane cycle. Budgets of methane that are consistent with source fluxes, isotopic and ice core measurements were determined. While it is not possible to come up with a single budget for CH{sub 4}, performing the calculation with a number of sets of assumed priors suggests a convergence in the allowed range for sources. In some cases -- wetlands (70-130 Tg/yr), rice paddies (60-125 Tg/yr) a significant reduction in the uncertainty of the source estimate is achieved. Our results compare favorably with the most recent measurements of flux estimates. For comparison, a similar analysis using bayes monte carlo simulation was performed. The question of the missing sink for carbon remains unresolved. Two analyses that attempt to quantify the missing sink were performed. First, a steady state …
Date: December 1, 1994
Creator: Kandlikar, M.
System: The UNT Digital Library
Evaluation of low-level radioactive waste characterization and classification programs of the West Valley Demonstration Project (open access)

Evaluation of low-level radioactive waste characterization and classification programs of the West Valley Demonstration Project

The West Valley Demonstration Project (WVDP) is preparing to upgrade their low-level radioactive waste (LLW) characterization and classification program. This thesis describes a survey study of three other DOE sites conducted in support of this effort. The LLW characterization/classification programs of Oak Ridge National Laboratory, Savannah River Site, and Idaho National Engineering Laboratory were critically evaluated. The evaluation was accomplished through tours of each site facility and personnel interviews. Comparative evaluation of the individual characterization/classification programs suggests the WVDP should purchase a real-time radiography unit and a passive/active neutron detection system, make additional mechanical modifications to the segmented gamma spectroscopy assay system, provide a separate building to house characterization equipment and perform assays away from waste storage, develop and document a new LLW characterization/classification methodology, and make use of the supercompactor owned by WVDP.
Date: December 31, 1994
Creator: Taie, K.R.
System: The UNT Digital Library