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

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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.

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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
De-Emphasize Direct Presence (open access)

De-Emphasize Direct Presence

The following paper reveals some aspects of my thoughts about art. The works discussed are featured in my M.F.A. exhibition. All works are mainly based on the ideas of absence, self-reference and utilization in art practice, even though each piece approaches the subject from differing angles. My dissatisfaction with preconceived notions in the contemporary art, rooted in art history, has shifted my focus from concerns of the direct, physical presence of artworks to the indirect or indecisive elements of their context. From this position I have felt free to explore the paradox of self-reference that is involved in performance. In addition, by transferring art works to functional objects, I have found a way to infuse everyday life with my art, and vice-versa. The ambiguity of interpreting artworks with language means that I present this paper with photographic documentation of my artwork. Combined, this will give a clear indication of the thrust of my graduate studies and the current theatrical direction of my art.
Date: August 2004
Creator: Chen, Xinpeng
System: The UNT Digital Library

Ethics Naturally: An Environmental Ethic Based on Naturalness

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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
Evaluating the Scalability of SDF Single-chip Multiprocessor Architecture Using Automatically Parallelizing Code (open access)

Evaluating the Scalability of SDF Single-chip Multiprocessor Architecture Using Automatically Parallelizing Code

Advances in integrated circuit technology continue to provide more and more transistors on a chip. Computer architects are faced with the challenge of finding the best way to translate these resources into high performance. The challenge in the design of next generation CPU (central processing unit) lies not on trying to use up the silicon area, but on finding smart ways to make use of the wealth of transistors now available. In addition, the next generation architecture should offer high throughout performance, scalability, modularity, and low energy consumption, instead of an architecture that is suitable for only one class of applications or users, or only emphasize faster clock rate. A program exhibits different types of parallelism: instruction level parallelism (ILP), thread level parallelism (TLP), or data level parallelism (DLP). Likewise, architectures can be designed to exploit one or more of these types of parallelism. It is generally not possible to design architectures that can take advantage of all three types of parallelism without using very complex hardware structures and complex compiler optimizations. We present the state-of-art architecture SDF (scheduled data flowed) which explores the TLP parallelism as much as that is supplied by that application. We implement a SDF single-chip …
Date: December 2004
Creator: Zhang, Yuhua
System: The UNT Digital Library

Evaluation of virulence in wild type and pyrimidine auxotrophs of Pseudomonas aeruginosa using the eukaryotic model system Caenorhabditis elegans.

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The human opportunistic pathogen, Pseudomonas aeruginosa PAO1, has been shown to kill the nematode Caenorhabditis elegans. C. elegans has been a valuable model for the study of bacterial pathogenesis, and has reinforced the notion that common virulence and host defense mechanisms exist. Recently, the pyrimidine pathway was shown to regulate virulence levels. Therefore, mutations in the pyrimidine pathway of PAO1 showed decrease virulence in the nematode. When starving the nematode, bacterial resistance was also shown to increase. It was hypothesized that starvation induced the DAF pathway, which regulates the transcription of genes involved with the antibacterial defense mechanism. Further research will be conducted to test this theory by performing RNAi experiments for the genes functioning in the antibacterial defense mechanism.
Date: August 2004
Creator: Anvari, Sara
System: The UNT Digital Library
Exploring flow among Division I and intramural athletes. (open access)

Exploring flow among Division I and intramural athletes.

This study explores the flow experiences of collegiate athletes. NCAA Division I athletes and intramural athletes (N = 180) completed a series of measures on their flow experiences. Comparisons were made regarding the characteristics of flow, the perceived facilitators of flow, the frequency of flow experiences, and explored the role of perceived ability. Using a person by situation interaction framework, this study singles out perceived ability as a person factor and competitive level as a situational factor to more clearly examine flow experiences. Results indicated distinctions between the two groups. Mainly, the intramural athletes reported experiencing the merging of action and awareness, autotelic experience, transformation of time and having clear goals more frequently than the NCAA Division I athletes. No group differences were found for flow frequency or flow facilitators. Perceived ability was found to have a weak, but significant relationship with specific flow facilitators and characteristics.
Date: May 2004
Creator: Peterson, Ryan J.
System: The UNT Digital Library

Functional analysis and elimination of SIB in an olive baboon (Papio hamadryas anubis).

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Self injurious behavior (SIB), such as self-biting and head-banging, has been reported to occur in approximately 10% of captive, individually housed primates (Novak, Kinsely, Jorgensen, and Hazen, 1998). Accounts of the causes of SIB range from environmental to physiological. However, to date, no researchers have investigated the possible influence of social consequences, delivered by handlers and keepers, in the maintenance of SIB. There is only one research report showing that self-injury can be shaped in primates by the manipulation of food as a reinforcing consequence for the animal's behavior. The current study investigated the effects of social contact as potentially reinforcing consequences for the SIB displayed by an olive baboon (Papio hamadryas anubis). Results indicated that the behavior was maintained by attention from humans. As treatment, reinforcement was arranged for an appropriate alternative attention-getting behavior, resulting in increases in the appropriate alternative behavior and decreases in SIB.
Date: August 2004
Creator: Dorey, Nicole R.
System: The UNT Digital Library
A general purpose semantic parser using FrameNet and WordNet®. (open access)

A general purpose semantic parser using FrameNet and WordNet®.

Syntactic parsing is one of the best understood language processing applications. Since language and grammar have been formally defined, it is easy for computers to parse the syntactic structure of natural language text. Does meaning have structure as well? If it has, how can we analyze the structure? Previous systems rely on a one-to-one correspondence between syntactic rules and semantic rules. But such systems can only be applied to limited fragments of English. In this thesis, we propose a general-purpose shallow semantic parser which utilizes a semantic network (WordNet), and a frame dataset (FrameNet). Semantic relations recognized by the parser are based on how human beings represent knowledge of the world. Parsing semantic structure allows semantic units and constituents to be accessed and processed in a more meaningful way than syntactic parsing, moving the automation of understanding natural language text to a higher level.
Date: May 2004
Creator: Shi, Lei
System: The UNT Digital Library
Ghosts and Lovers (open access)

Ghosts and Lovers

Ghosts and Lovers is a collection of short stories told from the points-of-view of four related characters. Travis is a bisexual restaurant owner who fears commitment and longs for the idealistic version of love that he remembers from his past. Ezra, his boyfriend, is an artist struggling to accept the inherent imperfections of life. Travis's ex-girlfriend, Beth, attempts to come to terms with the life that she has chosen for herself. Her husband, Richard, deals with feelings of helplessness as he watches the events of his life unfold before him. By depicting the events of the story from multiple perspectives, the collection attempts to create a more objective view of reality than is ordinarily possible in fiction. An introductory preface examines the role of unreliable narrators and how reality is presented in fiction.
Date: May 2004
Creator: Federer, Lisa M.
System: The UNT Digital Library
Green Improvements: A Consumer's Guide to Environmentally and Economically Responsible Home Repairs and Improvements for the North Central Texas Region (open access)

Green Improvements: A Consumer's Guide to Environmentally and Economically Responsible Home Repairs and Improvements for the North Central Texas Region

The Consumer's Guide is designed to help consumers by providing guidelines for the purchase of specific energy-efficient household appliances- water heaters, air conditioning and heating systems, windows, dishwashers, refrigerators, clothes washers, and dryers. This serves two major purposes: to decrease the environmental impact of those products and to save consumers money over the lifetime of the products. The seven major appliances covered in this work are things that consumers tend to purchase quickly when their older models wear out and with little research into their energy and/or water efficiency. The guide begins with a general introduction and an explanation of the need for energy conservation. Explanations of how they work, purchasing tips, installation tips, maintenance tips, tips for additional energy efficiency, and case studies are given for each appliance. Printable pamphlets are included at the end.
Date: August 2004
Creator: Dickason, Deborah
System: The UNT Digital Library
Heart rate and oxygen consumption during the critical prenatal period in chicken embryos (Gallus gallus): Influence of light cues and the onset of pulmonary ventilation. (open access)

Heart rate and oxygen consumption during the critical prenatal period in chicken embryos (Gallus gallus): Influence of light cues and the onset of pulmonary ventilation.

To examine if a rhythm can be entrained in either heart rate or oxygen consumption in late stage embryos (days 17-19.5) with light as a zeitgeber, chicken embryos were incubated in complete darkness (D:D) and 12:12 light:dark cycle (L:D). Light had no impact on oxygen consumption (390 µL O2∙min-1∙egg-1) but increased heart rate for non-internally pipped embryos (260 to 270 beats∙min-1 during light cycle). Oxygen consumption increased independent of pipping while heart rate increased (255 to 265 beats∙min-1) in D:D embryos due to pipping. A light-induced rhythm or effect occurred in heart rate but not oxygen consumption, suggesting heart rate and oxygen consumption may be uncoupled.
Date: December 2004
Creator: Brown, Jessie W.
System: The UNT Digital Library
Hematocrit, hematocrit Regulation and its effect on oxygen consumption in the late stage chicken embryo (Gallus domesticus). (open access)

Hematocrit, hematocrit Regulation and its effect on oxygen consumption in the late stage chicken embryo (Gallus domesticus).

Hematocrit and hematocrit regulation have the potential to affect developing embryos. To examine the ability of chicken embryos at day 15 to regulate hematocrit, they were subjected to either repeated saline injections (5% of total blood volume) or repeated blood removal (5% of total blood volume). Embryos showed an ability to maintain hematocrit (~20%) despite blood volume increases up to 115% of initial blood volume. Embryos were not able to maintain hematocrit in the face of dramatic blood volume loss. Oxygen consumption of embryos could be affected by their level of hematocrit. To examine this, chicken embryos at day 15, 16, and 17 of incubation were given a high hematocrit (~50-60%) sample of blood (400 μl) to artificially increase the hematocrit of the embryos (~10-12%). Despite the increase in oxygen availability, when monitored over a period of six hours, embryos showed no difference (0.36 ± 0.01 (ml O2 - min-1- egg-1) in metabolism from baseline measurements at day 15, 16 and 17.
Date: August 2004
Creator: Khorrami, Sheva
System: The UNT Digital Library
Histological age estimation of the midshaft clavicle using a new digital technique. (open access)

Histological age estimation of the midshaft clavicle using a new digital technique.

Histological methods to estimate skeletal age at death, in forensic cases, are an alternative to the more traditional gross morphological methods. Most histological methods utilize counts of bone type within a given field for their estimation. The method presented in this paper uses the percentage area occupied by unremodeled bone to estimate age. The percentage area occupied by unremodeled bone is used in a linear regression model to predict skeletal age at death. Additionally, this method uses digital software to measure area rather than the traditional technique in which a gridded microscope is used to estimate area. The clavicle was chosen as a sample site since it is not a weight bearing bone and has little muscular insertion. These factors reduce the variation seen as a result of differences in lifestyle or activity pattern.
Date: August 2004
Creator: Ingraham, Mark R.
System: The UNT Digital Library

Hopfield Networks as an Error Correcting Technique for Speech Recognition

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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
Identification and quantification of lipid metabolites in cotton fibers: Reconciliation with metabolic pathway predictions from DNA databases. (open access)

Identification and quantification of lipid metabolites in cotton fibers: Reconciliation with metabolic pathway predictions from DNA databases.

The lipid composition of cotton (Gossypium hirsutum, L) fibers was determined. Fatty acid profiles revealed that linolenate and palmitate were the most abundant fatty acids present in fiber cells. Phosphatidylcholine was the predominant lipid class in fiber cells, while phosphatidylethanolamine, phosphatidylinositol and digalactosyldiacylglycerol were also prevalent. An unusually high amount of phosphatidic acid was observed in frozen cotton fibers. Phospholipase D activity assays revealed that this enzyme readily hydrolyzed radioactive phosphatidylcholine into phosphatidic acid. A profile of expressed sequence tags (ESTs) for genes involved in lipid metabolism in cotton fibers was also obtained. This EST profile along with our lipid metabolite data was used to predict lipid metabolic pathways in cotton fiber cells.
Date: May 2004
Creator: Wanjie, Sylvia W.
System: The UNT Digital Library
Impact of actual interference on capacity and call admission control in a CDMA network. (open access)

Impact of actual interference on capacity and call admission control in a CDMA network.

An overwhelming number of models in the literature use average inter-cell interference for the calculation of capacity of a Code Division Multiple Access (CDMA) network. The advantage gained in terms of simplicity by using such models comes at the cost of rendering the exact location of a user within a cell irrelevant. We calculate the actual per-user interference and analyze the effect of user-distribution within a cell on the capacity of a CDMA network. We show that even though the capacity obtained using average interference is a good approximation to the capacity calculated using actual interference for a uniform user distribution, the deviation can be tremendously large for non-uniform user distributions. Call admission control (CAC) algorithms are responsible for efficient management of a network's resources while guaranteeing the quality of service and grade of service, i.e., accepting the maximum number of calls without affecting the quality of service of calls already present in the network. We design and implement global and local CAC algorithms, and through simulations compare their network throughput and blocking probabilities for varying mobility scenarios. We show that even though our global CAC is better at resource management, the lack of substantial gain in network throughput and …
Date: May 2004
Creator: Parvez, Asad
System: The UNT Digital Library
The Impact of Gender on Domestic Human Rights Abuse (open access)

The Impact of Gender on Domestic Human Rights Abuse

This study develops three models of human rights determinants with the inclusion an untested variable, women in parliaments. The research is conducted on pooled cross-sectional time-series data from 130 countries between 1978 and 1996. For the purpose of analysis the Prais-Winsten Regression method with Panel Corrected Standard Errors was used. The women in power variable is hypothesized to be significantly, positively correlated with a state's propensity toward respect for human rights and is operationalized as percentage of women in parliaments. Three models incorporating as control variables previously identified correlates of human rights abuse were utilized to asses the impact of percentages of women in parliaments on two individual subsets of human rights: personal integrity rights and socio-economic rights. Two models were designed to measure the subset of rights categorized as personal integrity rights using two separate measures: State Department Scores and Amnesty International Scores. Model number three utilized the Physical Quality of Life Index to measure levels of socio-economic rights. Statistical significance was demonstrated by the women in parliament variable in all three models.
Date: May 2004
Creator: Godwin, Donna D.
System: The UNT Digital Library

The impact of leisure travelers' characteristics on hotel Website attributes preference.

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Travel is now the largest online business-to-consumer product in the United States. Online hotel bookings are the second largest segment of online travel. Leisure travelers online spending will increase dramatically from 2002 to 2007. However, a majority of hospitality companies do not currently take advantage of the Internet as the cheapest and most efficient distribution medium. The purpose of this study examined leisure travelers' demographic and psychographic characteristics, online booking and travel frequency that influence travelers' desired hotel Website features and functions. The results found out that demographics (gender, occupation, and ethnicity), and psychographics (travel benefit sought), number of leisure travel trips per year, and number of online hotel bookings per year have impact on hotel Website attribute preferences.
Date: December 2004
Creator: Zhang, Li
System: The UNT Digital Library
Improvement of Homogeneity and Adhesion of Diamond-Like Carbon Films on Copper Substrates (open access)

Improvement of Homogeneity and Adhesion of Diamond-Like Carbon Films on Copper Substrates

Electrodeposition method is used to deposit diamond-like carbon (DLC) films on copper substrates via anodic oxidation at low temperature. These films are characterized using Raman spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Homogeneity of these films is studied using Raman spectroscopy and scanning electron microscopy. Scotch tape peel tests indicate adherent film on copper substrate. Carbon phase transformation is studied using thermal annealing experiments in conjunction with Raman spectroscopy and scanning electron microscopy. A cathodic electrochemical method is also studied to deposit diamond-like carbon films on copper substrates. However, films deposited by the cathodic route have poor adhesion and quality compared to anodically deposited films. It is also possible to grow diamond phase on copper substrates using acetylene in liquid ammonia via electrodeposition route. An electrochemical method is proposed for boron doping into DLC films.
Date: August 2004
Creator: Vavilala, Suma
System: The UNT Digital Library
Improving Performance in a Global Logistics Company: Operational Performance Before and After Process Improvement (open access)

Improving Performance in a Global Logistics Company: Operational Performance Before and After Process Improvement

The purpose of this study was to determine the effectiveness of an intervention designed to eliminate damage notification failures in a customer-specific standard operating procedure used by a global logistics company. Process maps identified locations in the process where damage notification failures could most likely occur. A revised process was designed overnight to eliminate as many notification failure points as possible. In addition, a job aid was included to help facilitate the process change for the drivers. The results of the intervention showed a rapid and profound decrease in damage notification failures leading to the retention of a large, profitable account with a minimal initial investment of time and money.
Date: December 2004
Creator: Dearman, Shawn Kale
System: The UNT Digital Library
The influence of a female high school art educator on the careers of her students. (open access)

The influence of a female high school art educator on the careers of her students.

Through the use of a feminist methodology, this qualitative case study examines the influence a high school art teacher, Pauline Gawlik, had on the career path of a group of her students, a high percentage of whom are Mexican American and/or of low socioeconomic status. Interviews of the teacher and seven of her former students revealed five themes related to the teacher's practice that affected her students' choice to become art teachers themselves: a positive classroom climate, confidence and focus, mutual respect and admiration, care, and mentoring. The results of this study hold implications for the current teacher shortage and the recruitment of Mexican American students into careers in art education.
Date: August 2004
Creator: McKnight, Pamela
System: The UNT Digital Library
Influence of Physically Active Leisure Participation on Obesity in Youth with Spina Bifida (open access)

Influence of Physically Active Leisure Participation on Obesity in Youth with Spina Bifida

Childhood obesity and resulting secondary complications in youth with disabilities are occurring in epidemic proportions, due in part to a trend of physical inactivity. The purpose of this study is to report the prevalence of overweight, the leisure time activity patterns, and the association between frequency of physically active leisure participation and body mass index for age, in a sample of 50 youth with spina bifida, ages 4.5 to 17.9 years. Results indicate that 52% of the sample are classified as at risk of overweight or overweight; 36% were male and 16% were female. The top five leisure time activities and team sport participation are identified. Subjects who did not use a wheelchair for ambulation participated significantly more in physically active leisure than subjects who used a wheelchair. Future research and rationale for physically active leisure as an intervention for youth with spina bifida are discussed.
Date: December 2004
Creator: McCabe, Erin
System: The UNT Digital Library

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

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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