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D. A. Kolb’s Theory of Experiential Learning: Implications for the Development of Music Theory Instructional Material

Description: This research project evaluates the effectiveness of specific music theory instructional strategies in terms of D. A. Kolb’s theory of experiential learning and Kolb’s typology of individual learning style. The project provides an original methodology for the adaptation of music theory instructional material to the individual learning style types described in Kolb’s typology. The study compares the relative effectiveness of two music theory instructional sequences, one of which is adapted for all of the learning style modalities described in Kolb’s typology, and the other adapted for only a limited number of Kolb’s learning style types. In order to compare the potential “learning outcomes” produced by these instructional sequences, a detailed study is proposed, in which computer based instruction (CBI) will deliver the instructional sequences to research participants and electronically record the participants’ responses. The current study demonstrates the effective aspects of the original methodology and suggests methods for the successful adaptation of music theory instructional material to individual student learning styles.
Date: August 2001
Creator: Lively, Michael
Partner: UNT Libraries

Electroproduction of Photons and of Pawns on the Proton in Quadrimoment of Transfer Q2=1.0GeV2. Measure Cross Sections and Extraction of Polarizabilities Generalities; Electroproduction de Photons et de Pions sur le Proton au Quadrimoment de Transfert Q2=1.0GeV2. Mesure des Sections Efficaces et Extraction des Polarisabilites Generalisees

Description: In hadronic physics, the nucleon structure and the quarks confinement are still topical issues. The neutral pion electroproduction and virtual Compton scattering (VCS) reactions allow us to access new observables that describe this structure. This work is focused on the VCS experiment performed at Jefferson Lab in 1998.
Date: November 6, 2001
Creator: Laveissiere, Geraud
Partner: UNT Libraries Government Documents Department

A Search for new physics in photon-lepton events in proton-antiproton collisions at {radical} s = 1.8 TeV

Description: We present the results of a search in p{bar p} collisions at {radical}s = 1.8 TeV for anomalous production of events containing a photon with large transverse energy and a lepton (e or {mu}) with large transverse energy, using 86 pb{sup -1} of data collected at the Collider Detector at Fermilab during the 1994-95 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (E{sub T}), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large E{sub T}, for which the probability of a statistical fluctuation of the standard model expectation up to and above the observed level is 0.7%.
Date: April 30, 2001
Creator: Berryhill, J. W.
Partner: UNT Libraries Government Documents Department

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 of the relaxation of second order moments such as beam size and emittance oscillations. This technique extends the well-known envelope equation formalism, and it can be applied to general systems with nonlinear forces. It is based on a systematic moment expansion of the Vlasov equation. In contrast to the envelope equation, which is derived assuming constant rms beam emittance, the CME model allows the emittance to vary through coupling to higher order moments. The CME model is implemented in slab geometry in the absence of return currents. The CME simulation yields rms beam sizes, velocity spreads and emittances that are in good agreement with particle-in-cell (PIC) simulations for a wide range of system parameters. The mechanism of relaxation is also considered within the framework of the CME system. It is discovered that the rapid relaxation or beam size oscillations can be attributed to a resonant coupling between different modes of the system. A simple analytical estimate of the relaxation time is developed. The final state of the system reached after the relaxation is complete is investigated. New and accurate analytical results for the second order moments in the phase-mixed state are obtained. Unlike previous results, these connect the final values of the second order moments with the initial beam mismatch. These analytical estimates are in good agreement with the CME model and PIC simulations. Predictions for the final density ...
Date: May 1, 2001
Creator: Backhaus, Ekaterina Yu.
Partner: UNT Libraries Government Documents Department

An Analysis of Teaching Periodicals for Aging Education Content

Description: Ninety elementary public school teachers were surveyed to find out where they obtained their teaching ideas. Seven popular elementary-level teaching periodicals, dated 1989-1999, were analyzed for aging-related content, and compared with 27 of the National Academy for Teaching and Learning about Aging (NATLA) aspects of aging recommended for students' learning. Results indicate that public elementary teachers obtain their teaching ideas from various places: teaching institutes or workshops; other teachers; ideas or lessons they develop themselves; and teaching periodicals. A large percentage obtain lesson ideas from teaching periodicals that they browse or read. This finding may assist NATLA in making recommendations to particular editorial boards. Surprisingly, few teachers obtain their teaching ideas from state and local curricular mandates. When the periodical issues were analyzed, aging-related content was categorized in four ways: informational articles with selected teaching or learning activities; articles describing intergenerational programs or activities; book reviews with selected learning activities; and book review titles mentioning older adult characters. Category totals among the 7 periodicals were highest in book review titles mentioning older adult characters and book reviews with selected learning activities. The content was compared to NATLA's recommendations for students' learning. The findings were not significant. The aging aspect that appeared most often in book reviews with selected learning activities was that most living things have life cycles of patterned biological changes, and/or that death and disability can occur at any age. Whether we formally teach them about aging or not, children learn about it. Earlier studies indicate that even preschool children may stereotype the aging process and/or older adults. Curricular and instructional ideas provided in teaching materials, even in an informal format can provide education, which prepares children for real life experiences.
Date: May 2001
Creator: Wimsatt, T. Joy
Partner: UNT Libraries

Effect of surface structure on catalytic reactions: A sum frequency generation surface vibrational spectroscopy study

Description: In the results discussed above, it is clear that Sum Frequency Generation (SFG) is a unique tool that allows the detection of vibrational spectra of adsorbed molecules present on single crystal surfaces under catalytic reaction conditions. Not only is it possible to detect active surface intermediates, it is also possible to detect spectator species which are not responsible for the measured turnover rates. By correlating high-pressure SFG spectra under reaction conditions and gas chromatography (GC) kinetic data, it is possible to determine which species are important under reaction intermediates. Because of the flexibility of this technique for studying surface intermediates, it is possible to determine how the structures of single crystal surfaces affect the observed rates of catalytic reactions. As an example of a structure insensitive reaction, ethylene hydrogenation was explored on both Pt(111) and Pt(100). The rates were determined to be essentially the same. It was observed that both ethylidyne and di-{sigma} bonded ethylene were present on the surface under reaction conditions on both crystals, although in different concentrations. This result shows that these two species are not responsible for the measured turnover rate, as it would be expected that one of the two crystals would be more active than the other, since the concentration of the surface intermediate would be different on the two crystals. The most likely active intermediates are weakly adsorbed molecules such as {pi}-bonded ethylene and ethyl. These species are not easily detected because their concentration lies at the detection limit of SFG. The SFG spectra and GC data essentially show that ethylene hydrogenation is structure insensitive for Pt(111) and Pt(100). SFG has proven to be a unique and excellent technique for studying adsorbed species on single crystal surfaces under high-pressure catalytic reactions. Coupled with kinetic data obtained from gas chromatography measurements, it can give ...
Date: September 7, 2001
Creator: McCrea, Keith R.
Partner: UNT Libraries Government Documents Department

Novel joining of dissimilar ceramics in the Si{sub 3}N{sub 4}-Al{sub 2}O{sub 3} system using polytypoid functional gradients

Description: A unique approach to crack-free joining of heterogeneous ceramics is demonstrated by the use of sialon polytypoids as Functionally Graded Materials (FGM) as defined by the phase diagram in the system, Si3N4-Al2O3. Polytypoids in the Al2O3-Si3N4 system offer a path to compatibility for such heterogeneous ceramics. The first part of the dissertation describes successful hot press sintering of multilayered FGM's with 20 layers of thickness 500 mm each. Transmission Electron Microscopy was used to identify the polytypoids at the interfaces of different areas of the joint. It has been found that the 15R polytypoid was formed in the Al2O3-contained layers and the 12H polytypoid was formed in the Si3N4-contained layers. The second part of the dissertation discusses the mechanical properties of these polytypoidally joined Si3N4-Al2O3. The thermal stresses of this FGM junction were analyzed using a finite element analysis program (FEAP) taking into account both coefficient of thermal expansion (CTE) and modulus variations. From this analysis, the result showed a dramatic decrease in radial, axial and hoop stresses as the FGM changes from three layers to 20 graded layers. Scaling was considered, showing that the graded transition layer should constitute about 75 percent or more of the total sample thickness to reach a minimal residual stress. Oriented Vickers indentation testing was used to qualitatively characterize the strengths of the joint and the various interfaces. The indentation cracks were minimally or not deflected at the sialon layers, implying strong interfaces. Finally, flexural testing was conducted at room temperature and at high temperature. The average strength at room temperature was found to be 581 MPa and the average strength at high temperature (1200 degrees C) was found to be 262 MPa. Scanning electron microscope observation of fracture surfaces at a different loading rates indicated that the strength loss at higher temperatures was ...
Date: August 22, 2001
Creator: Lee, Caroline Sunyong
Partner: UNT Libraries Government Documents Department

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 the final focus system following drift compression. In this thesis, several drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression. The occurrence of mismatches due to a rapidly increasing current was analyzed. In addition, the sensitivity of drift compression to errors in the initial velocity tilt and current profile was studied. These calculations were done using a new computer code that accurately calculates the longitudinal electric field in the space-charge dominated regime.
Date: May 1, 2001
Creator: de Hoon, M.J.L.
Partner: UNT Libraries Government Documents Department

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 Type IIA string theory, are also dualities of the noncommutative supersymmetric Yang-Mills description. One can also consider this as evidence for the accuracy of the Matrix Theory description of M-theory in this background. The second type of duality is the self-duality of theories with U(1) gauge fields. After discussing the general theory of duality invariance for theories with complex gauge fields, we are able to find a generalization of the well known U(1) Born-Infeld theory that contains any number of gauge fields and which is invariant under the maximal duality group. We then find a supersymmetric extension of our results, and also show that our results can be extended to find Born-Infeld type actions in any even dimensional spacetime.
Date: August 1, 2001
Creator: Brace, Daniel, M
Partner: UNT Libraries Government Documents Department

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 system. Previously known fast methods, available for isotropic problems, are discussed in detail. They introduce a family of new Ordered Upwinding Methods (OUM) for general (anisotropic) problems and prove convergence to the viscosity solution of the corresponding Hamilton-Jacobi partial differential equation. The hybrid methods introduced here are based on the analysis of the role played by anisotropy in the context of front propagation and optimal trajectory problems. The performance of the methods is analyzed and compared to that of several other numerical approaches to these problems. Computational experiments are performed using test problems from control theory, computational geometry and seismology.
Date: May 1, 2001
Creator: Vladimirsky, Alexander Boris
Partner: UNT Libraries Government Documents Department

The limit of strength and toughness of steel

Description: The ideal structural steel combines high strength with high fracture toughness. This dissertation discusses the governing principles of strength and toughness, along with the approaches that can be used to improve these properties and the inherent limits to how strong and tough a steel can be.
Date: December 17, 2001
Creator: Guo, Zhen
Partner: UNT Libraries Government Documents Department

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 compression air conditioning units, which are commonly known as chillers. Three different models were studied: two are based on first-principles and the third is empirical in nature. The first-principles models are the Gordon and Ng Universal Chiller model (2nd generation), and a modified version of the ASHRAE Primary Toolkit model, which are both based on first principles. The DOE-2 chiller model as implemented in CoolTools{trademark} was selected for the empirical category. The models were compared in terms of their ability to reproduce the observed performance of an older chiller operating in a commercial building, and a newer chiller in a laboratory. The DOE-2 and Gordon-Ng models were calibrated by linear regression, while a direct-search method was used to calibrate the Toolkit model. The ''CoolTools'' package contains a library of calibrated DOE-2 curves for a variety of different chillers, and was used to calibrate the building chiller to the DOE-2 model. All three models displayed similar levels of accuracy. Of the first principles models, the Gordon-Ng model has the advantage of being linear in the parameters, which allows more robust parameter estimation methods to be used and facilitates estimation of the uncertainty in the parameter values. The ASHRAE Toolkit Model may have advantages when refrigerant temperature measurements are also available. The DOE-2 model can be expected to have advantages when very limited data are available to calibrate the model, as long as one ...
Date: May 1, 2001
Creator: Sreedharan, Priya
Partner: UNT Libraries Government Documents Department

Optical spectroscopy of strongly correlated electron systems

Description: In this thesis, both time-resolved, nonlinear optical spectroscopy and linear spectroscopy are used to investigate the interactions and dynamics of elementary excitations in strongly correlated electron systems. In the first part, we investigate the renormalization of magnetic elementary excitations in the transition metal oxide Cr{sub 2}O{sub 3}. We have created a non-equilibrium population of antiferromagnetic spin waves and characterized its dynamics, using frequency- and time-resolved optical spectroscopy of the exciton-magnon transition. We observed a time-dependent pump-probe line shape, which results from excitation induced renormalization of the spin wave band structure. We present a model that reproduces the basic characteristics of the data, in which we postulate the optical nonlinearity to be dominated by interactions with long-wavelength spin waves, and the dynamics due to spin wave thermalization. Using linear spectroscopy, coherent third-harmonic generation and pump-probe experiments, we measured the optical properties of the charge-transfer (CT) gap exciton in Sr{sub 2}CuO{sub 2}Cl{sub 2}, an undoped model compound for high-temperature superconductors. A model is developed which explains the pronounced temperature dependence and newly observed Urbach tail in the linear absorption spectrum by a strong, phonon-mediated coupling between the charge-transfer exciton and ligand field excitations of the Cu atoms. The third-order nonlinear optical susceptibility within the Cu-O plane of Sr{sub 2}CuO{sub 2}Cl{sub 2} is fully characterized in both amplitude and phase, and symmetry based conclusions are made with respect to the spatial arrangement of the underlying charge distribution. Theoretical considerations ascribe a newly reported resonance in the third-order nonlinear susceptibility at 0.7 eV to a three-photon transition from the ground state to the charge-transfer exciton. An even parity intermediate state of Cudd character, is found to contribute to the transition. Finally, preliminary results of time-resolved pump-probe spectroscopy confirm that the CT exciton or one of its constituent parts couples strongly to phonons, and we ...
Date: February 27, 2001
Creator: Schumacher, Andreas B.
Partner: UNT Libraries Government Documents Department

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 first substantial investigation of polarized pump probe response in detwinned YBCO crystals is also reported. Dramatic doping dependent anisotropies along the a and b axes are observed in time and temperature resolved studies. Among many results, we highlight the discovery of an anomalous temperature and time dependence of a- axis response in optimally doped YBCO. We also report on the first observation of the photoinduced response in a magnetic field. We find the amplitude of the response, and in some cases, the dynamics considerably changed with the application of a 6T field. Finally, we speculate on two of the many theoretical directions stimulated by our results. We find that the two-fluid model suggests a mechanism to explain how changes at very low energies are visible to a high-energy probe. Also discussed are basic recombination processes which may play a role in the observed decay.
Date: May 1, 2001
Creator: Segre, Gino P.
Partner: UNT Libraries Government Documents Department

Animal Contribution to Human Medicine

Description: The use of animal models in research has led to a fierce debate between animal rights activists and scientists. The former claim that little useful information is gained from animal studies and the suffering of animals does not preclude any treatments which may be used to treat human illnesses. Yet, research scientists claim that in vivo animal models are of absolute necessity to developing treatments and cures to disease. To determine the necessity of animal use, one must examine the models currently in research. Have the animal models for disorders such as cystic fibrosis and muscular dystrophy given scientists enough information to develop effective treatments? This paper will examine the role of animal subjects in several disease research protocols, as well as the applicability of the research.
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Date: May 2001
Creator: Kvernes, Kayce
Partner: UNT Libraries

Activating Space within the Object and the Site

Description: I look at the world as a sculptor, examining physical constructs and implied meanings. My current research developed from my earlier studies of “containment” or, more specifically, “encapsulation,” creating visual, often physical, boundaries around selected content. Encapsulation confers a more active role than “containment”, a process rather than a result. This idea speaks to the issues of form, and asks the viewer to question the outside “shape of the form” in relation to the inside shape and content. My work focuses on exposed interior spaces and forms, allowing the viewer to enter the space physically as well as mentally and psychologically. Built in a large enough scale, the viewer could actually become the content. The sculpture’s interpretation revolves around the seen as well as the unseen. I built this duality into my work by using transparent and opaque materials. I also implemented small diameter stainless steel rod along with the transparent and opaque vinyl to reduce forms to their respective shapes and volumes. This approach allowed me to clean the “slate” of an object’s collective meaning and context, adapting it to the intent of my work.
Date: May 2001
Creator: Provence, Dana Noel
Partner: UNT Libraries

The Effects of Color Concentrate in Polyolefins.

Description: Throughout history consumer products were generally manufactured from wood and metal. They either had to hold their natural color or become subject to painting. When plastics entered the industry, it was recognized for its ease of shaping, re-usability, physical properties and its low cost. One of plastics' greatest benefits is its ability to hold a given color from within allowing it to avoid use of paint. This paper will give a brief overview on the effects of pigments when incorporated in a polyolefin. It will provide a classification of the main types of pigments and how each effect the properties of the product through: crystallization, weatherability, opacity, coloristic values and of course viscosity.
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Date: December 2001
Creator: Flora, Paul
Partner: UNT Libraries

Empowering the Black Community Faith-Based Economic Development

Description: This paper is addressed to the inner city and some suburban congregations seeking to express their faith through practical initiatives to revitalize their distressed communities. The paper seeks to inspire and instruct the reader with motivational stories containing illustrations of the valuable role that African-American congregations have played in stimulating economic development in their communities. The paper also shows the importance of African-Americans having some control over the flow of economic funds throughout the community. African-American churches in the inner city should undertake significant ventures in community economic development to minister to the temporal as well as the spiritual needs of their communities. This paper will demonstrate how the African-American church, with assistance from federal, state, local programs, and private concerns, can be effective in the urban revitalization.
Date: August 2001
Creator: Gipson, Phillip E.
Partner: UNT Libraries

Ceramics Without Clay: An Exploration into Potential

Description: Investigating the behavior, function and appearance of ceramic materials has proven an enduring point of interest throughout my education. In learning about the vast range of the earth-yielded materials and their physical manifestations in states ranging from wet to dry to fired, I have found myself excited and challenged to seek out ways to expand their presentation. My attention has been repeatedly drawn to the class of ceramic materials that frequently get classified as “glaze ingredients.” Understanding the structural and visual qualities of these minerals and compounds was an interest whether I was making tableware, tiles, or sculpture. For the purposes of this paper, I propose to deal expressly with the physical art-making considerations of material and process as they relate to my work in ceramics. By directing my focus as such, I hope to center my work on a concern that became evident to the art world upon the display of Marcel Duchamp’s Fountain: material equals content.
Date: May 2001
Creator: Hart, Christopher David
Partner: UNT Libraries

Gestural Expressions in Clay

Description: The nature of clay's physical attributes and the application of these characteristics to an expression of gestural movement in utilitarian ceramics.
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Date: August 2001
Creator: Neergaard, Nancy Dart
Partner: UNT Libraries

Formal Concerns in Conceptual Sculpture

Description: The problem I choose dealt with a new material to use in conceptual art. Since the nature of my work deals with ribbed sculptural forms that explore conceptual abstractions of recorded observations, I investigated a new material called composites. A composite is defined as two or more materials that are combined to share the best qualities of both. Laminated foam core, nylon fabric weave, vinyl, and resin composites may introduce an aesthetic and structural advantage to traditional material such as wood and metal. Innovations in laminated composites and methods of joining unfamiliar materials could offer an advantage for these new sculptures. A series of six ribbed sculptural forms were constructed, which consist of laminated composite material relating to personal observations expressed in my journal in the last quarter of the year 2000. The material was introduced in the desire for a cohesive formal relationship between the concepts and the forms. Patron, 2001 Mixed Media, 19"x 8"x 4"; PDQ, 2001 Mixed Media, 10"x 8"x 2"; PDQ2, 2001 Mixed Media, 21"x27"x3"; Bishop, 2001 Mixed Media, 23"x11"x5"; Coaster, 2001 Mixed Media, 14"x12"x9" and Putsch, 2001 Mixed Media, 69"x48"x24".
Date: May 2001
Creator: Stromberg, Matthew Gray
Partner: UNT Libraries