Degree Level

States

Design of Power Amplifier Test Signals with a User-Defined Multisine

Access: Use of this item is restricted to the UNT Community
Cellular radio communication involves wireless transmission and reception of signals at radio frequencies (RF). Base stations house equipment critical to the transmission and reception of signals. Power amplifier (PA) is a crucial element in base station assembly. PAs are expensive, take up space and dissipate heat. Of all the elements in the base station, it is difficult to design and operate a power amplifier. New designs of power amplifiers are constantly tested. One of the most important components required to perform this test successfully is a circuit simulator model of an entire communication system that generates a standard test signal. Standard test signals 524,288 data points in length require 1080 hours to complete one test of a PA model. In order to reduce the time taken to complete one test, a 'simulated test signal,' was generated. The objective of this study is to develop an algorithm to generate this 'simulated' test signal such that its characteristics match that of the 'standard' test signal.
Date: May 2004
Creator: Nagarajan, Preeti
System: The UNT Digital Library

The Effect of Breastfeeding Education on Breastfeeding Initiation Rates Among Teenage Mothers

Access: Use of this item is restricted to the UNT Community
The purpose of this study was to examine the effect of a breastfeeding education program on breastfeeding initiation rates, breastfeeding knowledge, and attitude towards breastfeeding among teenage mothers at an urban school for pregnant and parenting teens. Breastfeeding initiation rose from 35.7% in the control group to 85.2% in the treatment group. The mean score on the Breastfeeding Knowledge Subscale was significantly higher for the treatment group but not the control group. There was not a significant increase in mean scores on the Breastfeeding Attitude Subscale. Participants who initiated breastfeeding scored also had a significant increase in scores from pretest to posttest on the Breastfeeding Knowledge Subscale, while participants who did not initiate breastfeeding did not.
Date: May 2004
Creator: Brown, Amber L.
System: The UNT Digital Library

The Effects of Parent Training on the Amount and Variety of Food Consumed By a Child with Autism.

Access: Use of this item is restricted to the UNT Community
The current study assessed the effectiveness of a training package, delivered in the form of a manual, to teach a parent to increase the variety and amount of food consumed by her son. The participant was a 5-year-old boy with Pervasive Developmental Disorder and limited food consumption. A changing criterion design across two variables, variety of food and quantity of food, was used. Results were that the parent who used the manual, with limited assistance from the experimenter, did succeed in increasing food variety and quantity of target foods.
Date: May 2004
Creator: VanKirk, Tessa Schreiber
System: The UNT Digital Library

Effects of Thickness and Indenter Tip Geometry in Nanoindentation of Nickel Films

Access: Use of this item is restricted to the UNT Community
Nanoindentation has become a widely used technique to measure the mechanical properties of materials. Due to its capability to deform materials in micro- and nano-scale, nanoindentation has found more applications in characterizing the deformation behavior and determining the mechanical properties of thin films and coatings. This research deals with the characterization of samples received from Center for Advanced Microstructures and Devices (CAMD) and Integran Technologies Inc., Toronto, Canada and the objective of this investigation was to utilize the experimental data obtained from nanoindentation to determine the deformation behavior, mechanical properties of thin films on substrates and bulk materials, and the effect of geometrically different indenters (Berkovich, cubecorner, and conical). X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analysis were performed on these materials to determine the crystal orientation, grain size of the material, and also to measure any substrate effects like pile-up or sin-in respectively. The results indicate that indentation size effect (ISE) strongly depends on shape of the indenter and less sensitive to penetration depth where as the hardness measurements depends on shape of indenter and depth of penetration. There is a negligible strain rate dependency of hardness at deeper depths …
Date: May 2004
Creator: Parakala, Padma
System: The UNT Digital Library

Electrodeposition of adherent copper film on unmodified tungsten.

Access: Use of this item is restricted to the UNT Community
Adherent Cu films were electrodeposited onto polycrystalline W foils from purged solutions of 0.05 M CuSO4 in H2SO4 supporting electrolyte and 0.025 M CuCO3∙Cu(OH)2 in 0.32 M H3BO3 and corresponding HBF4 supporting electrolyte, both at pH = 1. Films were deposited under constant potential conditions at voltages between -0.6 V and -0.2 V vs Ag/AgCl. All films produced by pulses of 10 s duration were visible to the eye, copper colored, and survived a crude test called "the Scotch tape test", which stick the scotch tape on the sample, then peel off the tape and see if the copper film peels off or not. Characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray photon spectroscopy (XPS) confirmed the presence of metallic Cu, with apparent dendritic growth. No sulfur impurity was observable by XPS or EDX. Kinetics measurements indicate that the Cu nucleation process in the sulfuric bath is slower than in the borate bath. In both baths, nucleation kinetics do not correspond to either instantaneous or progressive nucleation. Films deposited from 0.05 M CuSO4/H2SO4 solution at pH > 1 at -0.2 V exhibited poor adhesion and decreased Cu reduction current. In both borate and sulfate baths, small …
Date: May 2004
Creator: Wang, Chen
System: The UNT Digital Library

Ethics Naturally: An Environmental Ethic Based on Naturalness

Access: Use of this item is restricted to the UNT Community
In this thesis I attempt to base an environmental ethic on a quality called naturalness. I examine it in terms of quantification, namely, as to whether it can quantified? I then apply the concept to specific areas such as restoration and conservation to create an environmental ethic and to show how such an ethic would be beneficial in general, and especially to policy issues concerning the environment. The thesis consists of three chapters: (1) the definition of nature and natural by way of a historical approach; (2) the place of humans in this scheme; and (3) the place of value and the discussion concerning quantification.
Date: May 2004
Creator: Leard, Jason
System: The UNT Digital Library

Hopfield Networks as an Error Correcting Technique for Speech Recognition

Access: Use of this item is restricted to the UNT Community
I experimented with Hopfield networks in the context of a voice-based, query-answering system. Hopfield networks are used to store and retrieve patterns. I used this technique to store queries represented as natural language sentences and I evaluated the accuracy of the technique for error correction in a spoken question-answering dialog between a computer and a user. I show that the use of an auto-associative Hopfield network helps make the speech recognition system more fault tolerant. I also looked at the available encoding schemes to convert a natural language sentence into a pattern of zeroes and ones that can be stored in the Hopfield network reliably, and I suggest scalable data representations which allow storing a large number of queries.
Date: May 2004
Creator: Bireddy, Chakradhar
System: The UNT Digital Library

Instigating a Necessary Epiphany in Visual Message-Making for Design Educators and Future Communication Designers

Access: Use of this item is restricted to the UNT Community
Man has used graphic signs and symbols to express a variety of thoughts and feelings since before the invention of writing; they have helped him to preserve the ideologies that have enabled him to articulate his conception of the world. Every culture in every historical era has invested the objects, animals and plants around it with a multitude of different psychological meanings to communicate its essential belief systems and social aspirations. In my document, I chose to shed light on the responsibility I believe design educators must assume regarding their ability to understand and teach the importance of how similar graphic signs, symbols, ideograms and icons are perceived differently by different cultures in the hyper-connected, inter-global economy of 21st century. It is very crucial not to discount the influence and correlation of symbolic, fundamental building blocks of design with the basic psychological functions that inform our subconscious, and are also informed by our individual social and cultural upbringings. People from different cultures may cognate these shapes similarly, but they perceive and encode their meanings based on their particular social and cultural influences. One-size-fits-all communication design solutions rarely work, especially when they are distributed to culturally diverse audiences, because various ethnic …
Date: May 2004
Creator: Sarkaria, Gagandeep
System: The UNT Digital Library

Key Components of a Comprehensive Visual Information System for College-Level Design Education Curriculum Analysis

Access: Use of this item is restricted to the UNT Community
Electronic and computer technology have advanced and transformed graphic design. New technologies are forcing design educators to constantly monitor and update their programs, creating a need for a system to be adopted by college-level institutions to better investigate, evaluate and plan art and design curriculum. The author identifies metaphorical approaches to designing a two-part solution, which includes a Comprehensive Visual Information System (CVIS) and Three-Dimensional Virtual Database (3DVDb), which assign volumetric form to education components based on the form, structure and content of a discipline. Research and development of the conceptual design for the CVIS and 3DVDb are intended to aid in the development of an electronic media solution to be made accessible to students, faculty and administrators.
Date: May 2004
Creator: Short, Scott Allen
System: The UNT Digital Library

Passivation effects of surface iodine layer on tantalum for the electroless copper deposition.

Access: Use of this item is restricted to the UNT Community
The ability to passivate metallic surfaces under non-UHV conditions is not only of fundamental interests, but also of growing practical importance in catalysis and microelectronics. In this work, the passivation effect of a surface iodine layer on air-exposed Ta for the copper electroless deposition was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Although the passivation effect was seriously weakened by the prolonged air exposure, iodine passivates the Ta substrate under brief air exposure conditions so that enhanced copper wetting and adhesion are observed on I-passivated Ta relative to the untreated surface.
Date: May 2004
Creator: Liu, Jian
System: The UNT Digital Library

Polymorphous

Access: Use of this item is restricted to the UNT Community
The first section explores how far I could stretch dichotomy in formal terms, while maintaining a visually resonant image. I wanted to manipulate a superficial surface filtered through "natural forms" as seen in scientific imagery. By this I wanted to create access to a place where forms could play and imagination could wander. I was seeking to find a confluence in seemingly opposing forces that would coexist in the same work. The second section answers questions I had established for myself. The most important discovery I made was about the true nature of what I called a dichotomy in my work. The last section discusses the conclusions drawn from mounting the Master of Fine Arts Exhibition. I found that my interests resided more in investigating an already confluent dualism, as opposed to reconciling a conflicting dichotomy.
Date: May 2004
Creator: Maxwell, Sarah
System: The UNT Digital Library

Preparation and characterization of praseodymium oxide films and powders.

Access: Use of this item is restricted to the UNT Community
Nanocrystalline praseodymium oxide films have been successfully generated on stainless steel substrates. The electrochemical deposition was performed in the cathode compartment of a divided electrochemical cell with a regular three-electrode configuration. The green films obtained by electrodeposition were then annealed at high temperatures for 1-3 hours. X-ray diffraction revealed the fluorite structure of Pr6O11 and the crystallite size was calculated. X-ray photoelectron spectroscopy was employed to study the composition of the oxide films and also the oxidation state of Pr. Scanning electron microscopy was utilized to study the surface texture and microstructure of deposits. Fourier transform infrared spectrometery was used to investigate the composition of the films. The effects of different conditions on the green films were also studied such as different pH values of the electrolyte solution, different deposition modes, different supporting electrolytes and different applied current densities. Sintering experiments were conducted to investigate the properties of the green films. Praseodymium oxide powders were also successfully prepared by combining electrochemical methods with sintering processes. The praseodymium oxide powders were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The crystallite sizes of the powders were evaluated.
Date: May 2004
Creator: Shang, Yajuan
System: The UNT Digital Library

The Relationship of Acculturation Stress and Leisure Satisfaction of Hispanic College Students

Access: Use of this item is restricted to the UNT Community
Hispanics are the fastest growing minority group in the U.S. and signs indicate a similar trend in their college enrollment. Leisure activities are known to have a moderating effect on individuals experiencing stress in their lives. Hispanic organizations registered with a major 4-year metropolitan university were targeted. The hypothesis for this study was there is no relationship between acculturation stress and leisure satisfaction. Results indicate no relationship between acculturation stress and leisure satisfaction. One explanation for this lack of a significant relationship between these two measures might be that these college students had obtained a high level of acculturation, which would explain the relatively low level of acculturation stress reported.
Date: May 2004
Creator: Pacleb, Selverio V.
System: The UNT Digital Library

The Rise, Fall, and Redemption of Oran M. Roberts

Access: Use of this item is restricted to the UNT Community
This thesis analyzes the political career of Oran M. Roberts during the critical period from 1850 to 1873. Through a reassessment of Roberts's extensive personal papers in the context of modern historical scholarship, the author explains how Roberts's political philosophy reflected the biases and prejudices typical of his era, as well as his own material interests and ambitions. Topic areas covered include Roberts's position on the Compromise of 1850, his constitutional philosophy, his involvement in the secession movement in Texas (including his service as president of the state secession convention), his military career during the Civil War, his participation in Presidential Reconstruction, his views on Congressional Reconstruction, and his role in the process of "redemption" in Texas.
Date: May 2004
Creator: Klemme, A. Christian
System: The UNT Digital Library

Space Vessels

Access: Use of this item is restricted to the UNT Community
The submarine and the spaceship fit in perfectly with the ideas of permanence and protection on which my work has been focusing. It is not coincidental that I have long been fascinated with the shapes and mechanisms of these vehicles. They are complex machines designed for a complex function; I find the precision of this to be appealing. I have used their shapes and mechanisms as design aspect in my thesis work. Also, in the studio, I have developed a type of Damascus steel bowl by modifying a technique once used for making gun barrels. I have made three small vessels inspired by spaceships and submarines using this modified technique.
Date: May 2004
Creator: Herndon, Mark
System: The UNT Digital Library

Study of Conductance Quantization by Cross-Wire Junction

Access: Use of this item is restricted to the UNT Community
The thesis studied quantized conductance in nanocontacts formed between two thin gold wires with one of the wires coated by alkainthiol self assembly monolayers (SAM), by using the cross-wire junction. Using the Lorenz force as the driving force, we can bring the two wires in contact in a controlled manner. We observed conductance with steps of 2e2 / h. The conductance plateaus last several seconds. The stability of the junction is attributed to the fact that the coating of SAM improves the stability and capability of the formed contact.
Date: May 2004
Creator: Zheng, Tao
System: The UNT Digital Library

Synthesis of cubic boron nitride thin films on silicon substrate using electron beam evaporation.

Access: Use of this item is restricted to the UNT Community
Cubic boron nitride (cBN) synthesis has gained lot of interest during the past decade as it offers outstanding physical and chemical properties like high hardness, high wear resistance, and chemical inertness. Despite of their excellent properties, every application of cBN is hindered by high compressive stresses and poor adhesion. The cost of equipment is also high in almost all the techniques used so far. This thesis deals with the synthesis of cubic phase of boron nitride on Si (100) wafers using electron beam evaporator, a low cost equipment that is capable of depositing films with reduced stresses. Using this process, need of ion beam employed in ion beam assisted processes can be eliminated thus reducing the surface damage and enhancing the film adhesion. Four sets of samples have been deposited by varying substrate temperature and the deposition time. scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) techniques have been used to determine the structure and composition of the films deposited. X-ray diffraction (XRD) was performed on one of the samples to determine the thickness of the film deposited for the given deposition rate. Several samples showed dendrites being formed as …
Date: May 2004
Creator: Vemuri, Prasanna
System: The UNT Digital Library

Use of Fading Procedures and Positive Reinforcement to Increase Consumption of Non-Preferred Food in a Child with Autism

Access: Use of this item is restricted to the UNT Community
Traditionally children with developmental disabilities who develop feeding issues can be at great risk for malnutrition. Failure to eat adequate amounts of food and/or insistence on eating a limited range of foods can be detrimental to a child's health and can lead to other behavioral difficulties. Feeding problems are difficult to treat because high levels of physical prompting can quickly create an aversion to eating as well as cause stress for both parents and children. Behavioral problems that range from moderate to extremely maladaptive can ensue. The question the present study addressed was whether or not a treatment package including only positive reinforcement and fading for a non-preferred food would result in independent eating of the targeted non-preferred food.
Date: May 2004
Creator: Vorpahl, Cresse Merchant
System: The UNT Digital Library

Utilization of Corridor Habitat by White-tailed Deer (Odocoileus virginianus) in Denton County, Texas

Access: Use of this item is restricted to the UNT Community
White-tailed deer (Odocoileus virginianus) (N=15) movements were determined with use of radio telemetry techniques to determine the utilization of corridor habitat on the Lake Ray Roberts Greenbelt Corridor (RRGC) in north central Texas. Home ranges were calculated using three estimation types. Male white-tailed deer tend to have home ranges twice that of female home ranges. Seasonal home ranges were largest during spring (Feb. - April) and fall (Aug. - Oct.) seasons. Males had greater seasonal variation in utilization than females. No statistically significant difference (p=0.24) between white-tailed deer locations when the RRGC experiences heavy human traffic compared to days when there is light human traffic. Linearity indices indicated home ranges less linear than expected (LI = 3.02). The RRGC should be maintained at its current status to provide a variety of vegetational types and protective cover for white-tailed deer and other wildlife of Denton County.
Date: May 2004
Creator: Bruce, Troy Kenneth
System: The UNT Digital Library

A Wet Etch Release Method for Silicon Microelectromechanical Systems (MEMS) Using Polystyrene Microspheres for Improved Yield

Access: Use of this item is restricted to the UNT Community
One of the final steps in fabricating microelectromechanical devices often involves a liquid etch release process. Capillary forces during the liquid evaporation stage after the wet etch process can pull two surfaces together resulting in adhesion of suspended microstructures to the supporting substrate. This release related adhesion can greatly reduce yields. In this report, a wet etch release method that uses polystyrene microspheres in the final rinse liquid is investigated. The polystyrene microspheres act as physical barriers between the substrate and suspended microstructures during the final liquid evaporation phase. A plasma ashing process is utilized to completely remove the polystyrene microspheres from the microstructure surfaces. Using this process, release yields > 90% were achieved. It is found that the surface roughness of gold surfaces increases while that of the silicon is reduced due to a thin oxide that grows on the silicon surface during the plasma process.
Date: May 2004
Creator: Mantiziba, Fadziso
System: The UNT Digital Library

Challenges Encountered During Law Enforcement Investigations of Terrorist Use of Information Technology.

Access: Use of this item is restricted to the UNT Community
The late 20th and early 21st centuries have seen a phenomenal growth in society's use of information technology. Criminals, including terrorists and terrorist organizations, have also adopted information technologies. Information technologies are used to enhance the efficiency, productivity, and effectiveness of terrorist activities and offenses. Investigating terrorist use of information technologies creates a number of challenges for law enforcement officials. While some of the challenges are encountered during conventional criminal investigations, terrorist investigations also present unique challenges. Through content and typological analysis, this study examined open source information to identify, categorize and propose a model of these challenges. Four primary categories were identified: technology, methodology, legal, and administration and human resources challenges.
Date: May 2005
Creator: Morgan, Deanne
System: The UNT Digital Library

Documentary Film: I Named Her Angel

Access: Use of this item is restricted to the UNT Community
Recent political developments in the world show us that different cultures need to know and understand each other better. Even though technological developments like the Internet, satellites, cable television and conglomeration of big media entities have made mass communication more effective and faster, we cannot easily say that these developments help to bring world cultures together. As a result, mass audiences are not very much able to see what few productions do speak to these issues in a constructive manner. The main aim of this documentary film project is to serve as a small step towards helping different cultures to understand each other better. This documentary film conveys the basics of Mevlevism by following the formal gatherings of a Mevlevi den in Istanbul, Turkey. A den or tekke is a place where Islamic people gather and perform their religious activities. During these gatherings they do the sema, they pray, they listen to music, and they discuss spiritual matters. Sema is the entire ritual they perform as part of their ceremonies including listening to music, singing and chanting to attain a state of religious emotion and ecstasy or vecd. The documentary film is structured around a twelve year old girl, Elif, …
Date: May 2005
Creator: Dinc, Nefin
System: The UNT Digital Library

A Drop of Oil

Access: Use of this item is restricted to the UNT Community
Many Christian writers point to God through their fiction without openly evangelizing. The images their words evoke lift their secular and religious readers' heads, for God is reflected in their use of language, the emotions they describe, and the actions of their characters. The preface and short stories in this collection aim to show that God's presence can be felt even when people are suffering due to human decisions and mistakes. He is with His creations in the midst of their pain to impart hope when they need it most.
Date: May 2005
Creator: Bullman, Carol
System: The UNT Digital Library

The Effects of Motivational and Instructional Self Talk on the Attentional Focus of High School Distance Runners.

Access: Use of this item is restricted to the UNT Community
The purposes of this study were to examine the (a) attentional focus strategies used by high school distance runners, (b) changes in attentional focus across four laps in three 1.6 km runs, and (c) effects of a pre-performance intervention using motivational and instructional self talk on the attentional focus strategies used by and performance of high school distance runners. Participants (N = 42) completed a background and demographic questionnaire, the Cross Country Attentional Focus Inventory (CCAFI), a motivational and instructional statement survey, and the Self-Motivation Inventory. A series of oneway ANOVAs revealed significant differences in the types of attentional strategies used by each group, as well as fluctuations in use of strategies. The experimental group associated more during the each of the 1.6 km trials, whereas the control group dissociated more throughout each trial. A significant group by week interaction was found, with the experimental group maintaining their performance and the control group slowing from week one to week three.
Date: May 2005
Creator: Burgess, Amber G.
System: The UNT Digital Library