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High Growth Rate Sic Cvd Via Hot-Wall Epitaxy, Rachael L. Myers-Ward

USF Tampa Graduate Theses and Dissertations

This dissertation research focused on the growth of 4H-SiC epitaxial layers in low-pressure horizontal hot-wall chemical vapor deposition (CVD) reactors. The goal of the research was to develop a growth process that maximized the growth rate and produced films of smooth morphology. The epitaxial growth of SiC was carried out in two different reactor sizes, a 75 mm reactor and a 200 mm reactor. The maximum repeatable growth rate achieved was 30-32 um/h in the 200 mm reactor using the standard chemistry of hydrogen-propane-silane (H2-C3H8-SiH4) at growth temperatures < ̲ 1600 °C, which is the highest growth rate reported to date in a horizontal hot-wall reactor at these temperatures. This growth rate was achieved with a silane flow rate of 30 sccm. The process development and characterization of 4H-SiC epitaxial films grown using the standard chemistry are presented.

There are many ways to increase the growth rate, such as changing …

Resonance Ultrasonic Vibrations (Ruv) For Crack Detection In Silicon Wafers For Solar Cells, William Dallas

USF Tampa Graduate Theses and Dissertations

The photovoltaic industry provides a pathway to allow renewable energy to meet world wide consumer energy needs. Past and present research and development on silicon based solar cells have helped make them the dominant player in the photovoltaic industry accounting for over 75% in 2005 as accounted by the US Department of Energy. One of the current technological problems is to identify and eliminate sources of mechanical defects such as thermo-elastic stress and cracks leading to the loss of wafer integrity and ultimately breakage of as-grown and processed Si wafers and cells.The RUV method, developed at the University of South …

Design And Evaluation Of New Power Management Methods To Reduce Direct And Induced Energy Use Of The Internet, Priyanga Chamara Gunaratne

USF Tampa Graduate Theses and Dissertations

The amount of electricity consumed by devices connected to the Internet in the U.S. has rapidly increased and now amounts to over 2% of total electricity used, which is about 74 TWh/yr costing over $6 billion annually. This energy use can be categorized as direct and induced. Much of this energy powers idle links, switches, and network-connected hosts and is thus wasted.This dissertation contains the first-ever investigation into the energy efficiency of Ethernet networks. A method for matching Ethernet link data rate with link utilization, called Adaptive Link Rate (ALR), is designed and evaluated. ALR consists of a mechanism to …

Multi-Criteria Decision Making In Outpatient Scheduling, Jana Iezzi

USF Tampa Graduate Theses and Dissertations

Hospital ambulatory patients are seen in outpatient departments (OPDs) located in the hospital. 83.3 million visits were made to these departments in 2002. Many sources of patient waiting time exist including: poor coordination of information, inefficient scheduling, inaccurate time estimation and others. Well-designed and executed patient scheduling has the potential to remedy some of these problems. To properly schedule patients, variability in demand must be addressed. Patients may cancel appointments, arrive late and arrive without appointments. We address this problem based on a Multi-attribute Decision Making (MADM) approach. Decision models are developed using the Simple Additive Weighting (SAW) method to …

Micro- And Nano-Scale Switches And Tuning Elements For Microwave Applications, Thomas P. Ketterl

USF Tampa Graduate Theses and Dissertations

In this work, various components for low power RF telemetry applications have been investigated. These designed, fabricated and tested devices include radio frequency (RF) micro-electro-mechanical systems (MEMS) switches, single-pole-double-throw (SPDT) RF MEMS switches, nano fabricated capacitors and switching devices, and micromachined microstrip patch antennas.Coplanar waveguide (CPW) RF capacitive switches in shunt and series configuration were designed for high isolation, low insertion loss, and fast switching speed. Switches with > 35 dB isolation, < 0.3 dB insertion loss and switching speeds in the 10's of microseconds were fabricated and measured. These switches were packaged using photo-imagable resists and flip-chip bonding techniques. The MEMS shunt switch topology was also implemented into a single-pole-double-throw (SPDT) design by utilizing two such switches in a series and a shunt configuration, offset by a quarter wavelength section to provide a RF shor

t at the input of the shunt switch in the off state. This type of design has the advantage of requiring a simple on-off (0 V and 35 V) …

Lean Manufacturers Transcendence To Green Manufacturing: Correlating The Diffusion Of Lean And Green Manufacturing Systems, Gary G. Bergmiller

USF Tampa Graduate Theses and Dissertations

Scientific evidence of human impact on the natural environment, such as global warming, continues to mount. Green manufacturing systems that focus on minimizing environmental impact of manufacturing processes and products are ever more important to our sustainable future. Green manufacturing systems are slow to gain acceptance as manufacturers are focused on implementing Lean manufacturing systems, generally considered the most competitive manufacturing systems in the world.

In recent years, researchers and the US Environmental Protection Agency (EPA) have sought to "build a bridge" between Lean and Green manufacturing systems, in hopes that the rapid expanse of Lean can serve as a …

Reliability-Centric Probabilistic Analysis Of Vlsi Circuits, Thara Rejimon

USF Tampa Graduate Theses and Dissertations

Reliability is one of the most serious issues confronted by microelectronics industry as feature sizes scale down from deep submicron to sub-100-nanometer and nanometer regime. Due to processing defects and increased noise effects, it is almost impractical to come up with error-free circuits. As we move beyond 22nm, devices will be operating very close to their thermal limit making the gates error-prone and every gate will have a finite propensity of providing erroneous outputs. Additional factors increasing the erroneous behaviors are low operating voltages and extremely high frequencies. These types of errors are not captured by current defect and fault …

Transmission Power Control For Wireless Sensors Networks, Karim Souccar

USF Tampa Graduate Theses and Dissertations

Energy saving, in battery operated wireless sensor networks, for the purpose of increasing the node and network lifetime, has gained substantial importance. This research was conducted with the objective of reducing the power consumption of the MICA2 sensors. The objective was pursued by manipulating the MAC layer, and by introducing a dynamic transmission power control algorithm. A new simulation tool was developed in order to reduce the complexity related to the design and testing of the transmission power control algorithm. The power control algorithm was also developed in the NesC language for the MICA2 sensors. In addition,several modifications were introduced …

Electromagnetic Characterization Of Miniature Antennas For Portable Devices, Diana P. Aristizabal

USF Tampa Graduate Theses and Dissertations

Advances in technology have placed a great emphasis on the design of broadband antennas as well as antenna miniaturization to cope with the demands of making electronic and handheld communication devices smaller and more efficient. In this thesis, the design and fabrication of a frequency independent antenna and a narrow-band planar microstrip Balun are presented. An analysis of frequency selective surfaces is also introduced in order to demonstrate their capability to miniaturize antenna thickness. Lastly, s-parameters measurements and efficiency characterization are performed to determine the radiation properties of surface mount chip inductors in order to determine the feasibility of using …

Ieee 802.11b Wireless Lan Sensor System And Antenna Design, Leonard Guerra

USF Tampa Graduate Theses and Dissertations

A novel approach to miniaturizing an 802.11b WLAN card using folded-flex ultra-thin substrates is presented. A 73 percent reduction in size was realized using hybrid circuits on FR4 and polyimide. There is even more potential for further reduction if more copper layers are used. The miniaturized 802.11b WLAN cards were used to design 802.11b wireless sensor nodes. A research test-bed was setup to study how 802.11b networked sensor nodes could operate in the field. There are many applications for such sensor networks like habitat monitoring, object tracking, seismic detection, military surveillance, or fire detection to name a few. This investigation …

Are Respiratory Behaviors Affected In Individuals With Adductor Spasmodic Dysphonia?, Katie Biedess

USF Tampa Graduate Theses and Dissertations

Adductor spasmodic dysphonia (ADSD) is a focal dystonia that is characterized by voice breaks due to involuntary contractions of the adductor muscles of the vocal folds. These spasms can interfere with the coordination and balance of the respiratory and phonatory systems interfering with normal voice production. Disruptions in normal respiratory behaviors are well documented in inviduals with laryngeal disorders, including ADSD. Previous research regarding respiratory processes in ADSD has focused on airflow and pressure; however, there are many other parameters that have not been considered and may shed new light on the respiratory behaviors of individuals with ADSD. Therefore, the …

Mathematical Model Of Arsenic Adsorption In A Modified Zeolite / Microfiltration System, Miles B. Beamguard

USF Tampa Graduate Theses and Dissertations

Carcinogenic health concerns over arsenic in drinking water caused the USEPA to reduce the maximum contaminant level (MCL) from 50 to 10 ppb, effective on January 23, 2006. This has forced many smaller utilities into expensive treatment or discontinuation of water distribution. Researchers throughout the world are working to develop an inexpensive method for arsenic removal to meet this MCL. Aluminum silicates, or zeolites, are naturally occurring ionic sorbents. Modification of a zeolite may enhance adsorption capacities and ion selectivity. This research investigates the arsenic adsorption capacities of a modified Chabazite. This adsorption, coupled with a hollow fiber, microfiltration membrane …

Gene Expression Profiles And Clinical Parameters For Survival Prediction In Stage Ii And Iii Colorectal Cancer Patients, Mubeena Begum

USF Tampa Graduate Theses and Dissertations

Prediction of outcome in colorectal cancer (CRC) is currently based on the TNM staging classification; however, histopathological classification alone is insufficient for accurately predicting survival in stage II and III patients. Studies indicate that microarray gene expression profiles can predict survival in CRC. We hypothesize that tumor gene expression in combination with clinical parameters, is a better predictor of outcome in stage II and III colorectal cancers than the TNM stage classification alone. Clinical records and follow-up data were retrospectively reviewed for 58 Stage II and Stage III patients with primary colorectal cancer, who did not receive any neoadjuvant therapy …

Arts In New Directions The Development And Application Of A Construct That Uses The Arts To Promote Transformation And Self-Actualization In Health Care And Education/Therapy, Alexxis Avalon

USF Tampa Graduate Theses and Dissertations

Artistic methods to evoke relaxation, spark creativity, and change self-perceptions are already being used by therapists, educators, and scientists. Interdisciplinary collaborations among researchers are developing to create new paradigms that incorporate the use of arts to empower individuals. By describing various connections between the arts and participants, researchers are looking at the expressive arts (including dance, music, drama, poetry, and visual arts) for transformation and self-actualization.The problem is that no construct is available to describe the transformation, "the conscious move from one deep structure of knowledge to another" (Wilber, 2004), that occurs when using the arts in health care and …

Comparing The Effects Of The Exotic Cactus-Feeding Moth, Cactoblastis Cactorum (Berg) (Lepidoptera: Pyralidae) And A Native Cactus-Feeding Moth, Melitara Prodenialis (Walker) (Lepidoptera: Pyralidae) On Two Species Of Florida Opuntia., Amanda J. Baker

USF Tampa Graduate Theses and Dissertations

Exotic species are a great concern because of the possibility of negative effects once they become established. The exotic cactus moth, Cactoblastis cactorum has a reputation for being detrimental to Opuntia populations throughout Florida and the southeastern United States. Multiple projects are currently underway to attempt to contain and eradicate this species before it can migrate to the Opuntia-rich desert southwest and the agricultural Opuntia fields in the Mexican highlands. These projects have been undertaken without previous studies to determine what negative effects, if any, the moth is having on the common native Opuntia species. This is understandable; since it …

Implications Of Sleep Disorders Symptoms On School Behavior, Academics, And Quality Of Life, Erin Elizabeth Ax

USF Tampa Graduate Theses and Dissertations

Pediatric sleep problems are among the most common yet significant pediatric health issues faced by families. Sleep problems can impact social-emotional and academic functioning of schoolchildren. Once identified, pediatric sleep problems and disorders are treatable with effective and rapid behavioral and medical interventions. The purpose of the current study was to determine the prevalence rates of symptoms of sleep disorders in a diverse school-based sample as well as the relationship between symptoms of sleep disorders and school behavior, academic achievement, and quality of life. The present study examined the relationship between the independent variables of No Sleep Disorders symptoms and …

Adolescent Alcohol Use And Educational Outcomes, Wesley A. Austin

USF Tampa Graduate Theses and Dissertations

There is some controversy over whether adolescent alcohol use has deleterious causal effects on educational outcomes. In particular, does drinking reduce academic performance and school enrollment rates and increase truancy, or does the observed negative correlation between drinking and educational outcomes merely reflect common unobservable factors? This dissertation sheds further light on the issue by estimating the causal impacts of alcohol use on various educational outcomes. Specifically, an instrumental variables model is estimated to study the effects of several drinking measures on grades, school enrollment and absenteeism.

Study Of Laplace And Related Probability Distributions And Their Applications, Gokarna Raj Aryal

USF Tampa Graduate Theses and Dissertations

The aim of the present study is to investigate a probability distribution that can be derived from the laplace probability distribution and can be used to model various real world problems. In the last few decades, there has been a growing interest in the construction of flexible parametric classes of probability distributions. Various forms of the skewed and kurtotic distributions have appeared in the literature for data analysis and modeling. In particular, various forms of the skew laplace distribution have been introduced and applied in several areas including medical science, environmental science, communications, economics, engineering and finance, among others. In …

Crystal Engineering Of Organic Compounds Including Pharmaceuticals, Joanna A. Bis

USF Tampa Graduate Theses and Dissertations

Neutral or charge-assisted hydrogen bonds occurring between organic molecules represent strong and directional forces that mediate the molecular self-assembly into well defined supramolecular architectures. A proper understanding of hydrogen bonding interactions, their types, geometries, and occurrence in supramolecular motifs, is a prerequisite to crystal engineering, i.e. to the rational design of functional solid materials.Multiple-component organic crystals represent ideal systems to study the intermolecular interactions between the constituent molecules that can be pre-selected for their hydrogen bonding sites and geometrical capabilities. In particular, the systematic structural analysis of supramolecular systems that are comprised of simple molecules facilitates the development of strategies …

A Case Study Of A School Implementing A Constructivist Philosophy, Joseph C. Brown

USF Tampa Graduate Theses and Dissertations

Isaacson's (2004) dissertation chronicles the implementation of a constructivist instructional approach at Southwood Elementary School. Southwood's faculty experienced a change of principals, which the Tri-Partite Theory of Organizational Change and Succession, a theory of organizational entropy, predicts could lead to organizational entropy. This study examines the dynamics of the change in principal, as well as Isaacson's recommendation to study teachers' perceptions regarding the maintenance of the constructivist approach. This study answers three questions: 1) Are faculty still using constructivist strategies? 2) What are teacher perceptions regarding the maintenance and support of constructivist philosophy? 3) Is there congruence between what literature …

Regulation Of Transcription And Analysis Of Drug Targets In Lymphoma And Myeloma Cells, Sophia C. E Bolick

USF Tampa Graduate Theses and Dissertations

Hematological malignancies, such as lymphomas and myelomas, have low cure rates or remain refractory to treatment, although advances have been made in treatment regimens for these patients. Questions still remain as to what is occurring in these cells on a molecular level, specifically at the level of gene transcription. The positive regulatory domain I binding factor 1 (PRDI-BF1) has been shown to directly repress genes required for cell proliferation and maintenance of the B cell phenotype, however very little is known as to its regulation. The first study presented in this dissertation demonstrates regulation of the PRDM1 gene occurs primarily …

Teaching Strategies Of Successful College Trombone Professors For Undergraduate Students, Matthew T. Buckmaster

USF Tampa Graduate Theses and Dissertations

This study identified teaching strategies of successful trombone professors for undergraduate trombone students. Participants were three professors at accredited colleges in the United States who had received international awards in the field of trombone pedagogy. A comprehensive interview instrument was administered to each participant in a multiple case studies research design. From the gathered data, a classical content analysis revealed 79 emergent themes from 375 coded passages, with 45 of the emergent themes being commonalities among the three participants. In addition to specific teaching strategies, three meta-themes emerged from an examination of these commonalities: Product Over Process, Individualized Teaching Approaches, …

B-Raf Is An Essential Component Of The Mitotic Machinery Critical For Activation Of Mapk Signaling During Mitosis In Xenopus Egg Extracts, Sergiy I. Borysov

USF Tampa Graduate Theses and Dissertations

Activation of the MAPK cascade during mitosis is critical for spindle assembly and normal mitotic progression. The underlying regulatory mechanisms that control activation of the MEK/MAPK cascade during mitosis are poorly understood. The goal of my dissertation research is to identify the MEK kinase responsible for activation of the MAPK cascade during mitosis and to elucidate the biochemical mechanisms that regulate its activity. In the described herein work I purified and characterized the MEK kinase activity present in M-phase arrested Xenopus egg extracts. I demonstrate that B-Raf is the critical MEK kinase required for activation of the MAPK pathway at …

Statistical Modeling And Assessment Of Software Reliability, Louis Richard Camara

USF Tampa Graduate Theses and Dissertations

The present study is concerned with developing some statistical models to evaluate and analyze software reliability. We have developed the analytical structure of the logistic model to be used for testing and evaluating the reliability of a software package. The proposed model has been shown to be useful in the testing and debugging stages of the developmental process of a software package. It is important that prior to releasing a software package to marketing that we have achieved a target reliability with an acceptable degree of confidence. The proposed model has been evaluated and compared with several existing statistical models …

Enzyme Linked Spectroscopic Assays For Glyoxylate; The Use Of Peptidylglycine Alpha-Amidating Monoxygenase For The Discovery Of Novel Alpha-Amidated Hormones, Sarah Elizabeth Carpenter

USF Tampa Graduate Theses and Dissertations

Peptide hormones are responsible for cellular functions critical to the survival of an organism. Approximately 50% of all known peptide hormones are post-translationally modified at the C-terminus. Enzymatic oxidative conversion of C-terminal glycine extended peptide precursors results in an a-amidated peptide and glyoxylate. Peptidylglycine a-amidating monooxygenase (PAM) is the single known enzyme responsible for catalyzing this reaction. PAM is an O2, Cu(II), and Zn(II) dependent bifunctional enzyme. Initially, PAM hydroxylates the glycyl a-carbon followed by dealkylation of the hydroxylated intermediate to an a-amidated product and glyoxylate. PAM is also responsible for the conversion of glycine extended fatty acids to fatty …

Stabilization Of Marginal Soils Using Recycled Materials, Delfin G. Carreon

USF Tampa Graduate Theses and Dissertations

Marginal soils, including loose sands, soft clays, and organics are not adequate materials for construction projects. These marginal soils do not possess valuable physical properties for construction applications. The current methods for remediation of these weak soils such as stone columns, vibro-compaction, etc. are typically expensive. Waste materials such as scrap tires, ash, and wastewater sludge, offer a cheaper method for stabilizing marginal soils. As an added benefit, utilizing waste materials in soil stabilization applications keeps these materials from being dumped into landfills, thereby saving already depleting landfill space. Included in this report is an extensive investigation into the current …

Cloning And Analysis Of Putative Collagenases Of The U32 Family In Streptococcus Mutans And Streptococcus Agalactiae (Group B Streptococci), Valerie Carson

USF Tampa Graduate Theses and Dissertations

Analysis of the genomic sequences of Streptococcus mutans UA159 and Group B Streptococcus (GBS) strains Streptococcus agalactiae NEM316 and S. agalactiae 2603V/R indicated the presence of two putative collagenase genes in each organism. smcol1 from S. mutans was previously cloned and analyzed and the results indicated that the enzyme belonged to the U32 family of collagenases/peptidases. This enzyme shares homology with the prtC of Porphyromonas gingivalis, one of the principal examples of the U32 family of peptidases. Considering the potential role of these enzymes in the pathogenicity of P. gingivalis (periodontitis or gum disease), GBS (premature rupture of the amniochorionic …

Cue Reactivity And The Role Of Social Alcohol Expectancies In The College-Aged Drinking Population, Ashlee C. Carter

USF Tampa Graduate Theses and Dissertations

Research has shown alcohol expectancies to be critically important in understanding maladaptive drinking patterns within alcohol use disorders. Alcohol expectancies, thought to be automatically elicited in the presence of environmental alcohol-related cues, represent both cognitive and affective associations with drinking behavior. However, the automatic and affective properties of alcohol expectancies have not yet been thoroughly measured in the literature. Psychophysiological measures, including skin conductance, heart rate, and the acoustic startle response in particular, offer a uniquely powerful set of indices for the automatic affective processing of alcohol-related cues.

Therefore, the present study was designed to examine how alcohol expectancies moderate …

The Hearing Abilities Of Elasmobranch Fishes, Brandon M. Casper

USF Tampa Graduate Theses and Dissertations

The hearing abilities of elasmobranch fishes were examined in response to several types of stimuli using auditory evoked potentials (AEP). Audiograms were acquired for the nurse shark, Ginglymostoma cirratum, the yellow stingray, Urobatis jamaicensis, in a controlled environment using a monopole underwater speaker. A dipole stimulus was used to measure the hearing thresholds of the horn shark, Heterodontus francisi, and the white-spotted bamboo shark, Chiloscyllium plagiosum. The dipole experiments yielded much lower thresholds than any other experiment, suggesting that this type of sound specifically stimulated the macula neglecta by creating a strong velocity flow above the head of the shark. …

Folk Wiki: The Shared Traditions Of Folk Music And The Wiki Way, Phillip Mark Chamberlin

USF Tampa Graduate Theses and Dissertations

Wiki is often perceived as representing a revolutionary break from conventional notions of authorship, writing, and textual history. Dialogues concerning Wiki tend to ignore the characteristics that Wiki shares with earlier forms of collaboration, particularly folk music. In both Wiki and folk music, content is often collectively shared and authored, even if specific individuals create and change the content. Many collaborators are anonymous, quasi-anonymous, or pseudo-anonymous, but the perception of this anonymity is, in both genres, problematic. Second, both Wiki documents and folk songs exist in the "Eternal Now," a seemingly perpetual state that makes these texts available for addition, …