American Studies Commons^™

Generation Of Carbon Dioxide And Mobilization Of Antimony Trioxide By Fungal Decomposition Of Building Materials, John D. Krause

USF Tampa Graduate Theses and Dissertations

Fungal contamination of buildings poses numerous challenges to researchers, building owners and occupants. Public health agencies promote prevention and remediation of mold and water damage, but lack sensitive methods to detect hidden mold growth and a complete understanding of the biological mechanisms that make occupying moldy buildings a hazard. The wide spread use of the fire retardant antimony trioxide (Sb₂O₃) on building materials and furnishings makes it inevitable that mold growth on treated materials will occur in some buildings with water damage. Several authors have speculation that microbial growth on materials treated with antimony trioxide could …

Integrated Scheduling And Information Support System For Transit Maintenance Departments, Paula Andrea Lopez Alvarado

USF Tampa Graduate Theses and Dissertations

The projected increase of population in the United States and particularly in the state of Florida shows a clear need of improvement in mass transportation systems. To provide outstanding service to rides, well maintained fleet that ensures safety for riders and other people on the streets is imperative.

This research presents an information support system that assists maintenance managers to review and analyze data and evaluate alternatives in order to make better decisions that maximize efficiency in operations at transportation organizations. A system that consists of a mathematical scheduling model that interacts with a forecasting model and repair time standards …

Effect Of Chromium Vi On The Production And Behavior Of Lytechinus Variegatus (Echinodermata: Echiniodea), Jennifer Rhora

USF Tampa Graduate Theses and Dissertations

Small amounts of chromium (VI) are carcinogenic in mammals. Concentrations of Cr in marine algae and seagrasses range from 0.06-7.17 /g DW and 0.1-30.6 g/g DW respectively. To test for an effect of these concentrations, production (change in organic material), righting response, feeding rates, absorption efficiency and fecal production were measured in Lytechinus variegatus from Sarasota fed prepared diets containing 0, 4.1, and 32g Cr/ g DW and individuals from Ft. DeSoto fed diets containing 0, 41 and 82g Cr/ g DW. The urchins were fed for 4-5 weeks, with weekly measurements of their feeding rates, absorption efficiency and fecal …

Seasonal And Spatial Trends Of Karenia Brevis Blooms And Associated Parameters Along The 10-Meter Isobath Of The West Florida Shelf, Elizabeth Singh

USF Tampa Graduate Theses and Dissertations

Karenia brevis is a toxic marine dinoflagellate species that blooms almost every year in the Gulf of Mexico. These blooms have had devastating effects on local economies, as well as on the fauna of the area. The ECOHAB:Florida project was founded to study the population dynamics and trophic impacts of K. brevis. The project included a series of monthly hydrographic offshore research cruises, as well as monthly surveys of a transect along the 10-meter isobath of the West Florida Shelf. This study focused on data from the alongshore transect over a three-year period (1999-2001). Physical parameters (temperature, salinity, and …

Effect Of Fiber Volume Fraction On Fracture Mechanics In Continuously Reinforced Fiber Composite Materials, Thomas Wasik

USF Tampa Graduate Theses and Dissertations

The application of advanced composite materials, such as graphite/epoxy, has been on the rise for the last four decades. The mechanical advantages, such as their higher specific stiffness and strength as compared to monolithic materials, make them attractive for aerospace and automotive applications. Despite these advantages, composites with brittle fibers have lower ductility and fracture toughness than monolithic materials.

One way to increase the fracture toughness of composites is to have a weak fiber-matrix interface that would blunt crack tips by crack deflection into the interface and hence enhance fracture toughness. However, this also reduces the transverse properties of the …

Performance Evaluation Of Mobile Ad Hoc Networks In Realistic Mobility And Fading Environments, Preetha Prabhakaran

USF Tampa Graduate Theses and Dissertations

Mobile Ad hoc Networks (MANETs) are wireless networks, which consist of a collection of mobile nodes with no fixed infrastructure, where each node acts as a router that participates in forwarding data packets. They are a new paradigm of wireless communications for mobile hosts that are resource-constrained with only limited energy, computing power and memory.

Previous studies on MANETs concentrated more on energy conservation in an idealistic environment without taking into consideration, the effects of realistic mobility, interference and fading. The definition of realistic mobility models is one of the most critical and, at the same time, difficult aspects of …

Partial Evaluation Based Triple Modular Redundancy For Single Event Upset Mitigation, Sujana Kakarla

USF Tampa Graduate Theses and Dissertations

We present a design technique, called partial evaluation triple modular redundancy for hardening combinational circuits against Single Event Upsets (SEU). The input environment is given in terms of signal probabilities of the lines. This is useful information to determine the redundant gates of the given circuit. The basic ideas of partial redundancy and temporal triple modular redundancy are used together to harden the circuit against SEUs. The concept of partial redundancy is used to eliminate the gates whose outputs can be determined in advance. This technique fails in cases when the actual inputs to the circuit are not in accordance …

Bottom-Up And Top-Down Effects On Insects Herbivores Along A Natural Salinity Gradient In A Florida Salt Marsh, Maria Teresa Albarracin

USF Tampa Graduate Theses and Dissertations

I compared the strength of bottom- up and top-down effects on insect herbivores along a natural salinity gradient in salt marsh communities in West - Central, Florida. I used a 2x2 factorial design with plots divided into four different treatments: 1) fertilizer applied to increase plant quality 2) sticky traps added to remove natural enemies (parasitoids) 3) fertilizer applied and sticky traps added and 4) control plots. These plots were placed on 7 different sites containing the salt marsh plant Borrichia frutescens along a natural stress salinity gradient. In each plot I determined the abundance of the sap sucker Pissonotus …

An Investigation Of Tio2-Znfe2O4 Nanocomposites For Visible Light Photocatalysis, Jeremy Wade

USF Tampa Graduate Theses and Dissertations

Environmental pollution on a global scale is expected to be the greatest problem that chemical scientists will face in the 21st century, and an increasing number of these scientists are looking to new photocatalytic systems for the solution. Existing photocatalytic systems are effective for the decomposition of many unwanted organics through the use of efficient semiconductor photocatalysts activated by ultra-violet (UV) irradiation. The demand for visible light activated photocatalytic systems is increasing rapidly. Currently, however, the efficiency and availability of photocatalysts which can be activated effectively by the solar spectrum and especially indoor lighting is severely limited.

The purpose of …

Novel Rectenna For Collection Of Infrared And Visible Radiation, Mohammad Sarehraz

USF Tampa Graduate Theses and Dissertations

This dissertation presents the rectifying antennas potential for harvesting solar power, along with a novel design for a solar rectenna. The suns general features and the characteristics of solar radiation as an electromagnetic wave are treated in depth in order to determine the deficiencies of traditional rectennas as a solar cell. A closed form equation for a MIM rectifiers efficiency as a function of its input power was developed and verified by a simulated behavioral model and measurements. A unique calculation method was also developed to determine the available solar power at the terminal of a [lambda]/2 dipole antenna as …

Structural And Electrical Properties Of Barium Strontium Titanate Thin Films For Tunable Microwave Applications, Sriraj G. Manavalan

USF Tampa Graduate Theses and Dissertations

The dependence of dielectric permittivity on the applied electric field, high dielectric constant and low cost makes barium strontium titanate (BST) a promising ferroelectric material for applications in tunable microwave devices. High tunability and low dielectric loss is desired for tunable microwave devices. The primary objective of this research was to optimize the tunability and dielectric loss of BST thin films at microwave frequencies with different deposition techniques. Ba0.5Sr0.5TiO3 thin films were grown on Pt/TiO₂/SiO₂/Si, by pulsed laser deposition (PLD) and sputtering. Parallel plate capacitor structures were designed using ADS and fabricated. The microstructural and phase …

Cds/Cdte Thin Film Solar Cells With Zinc Stannate Buffer Layer, Srilatha Bapanapalli

USF Tampa Graduate Theses and Dissertations

CdS/CdTe solar cell performance and reproducibility can be improved by integrating a ZTO buffer layer, which interdiffuses into the CdS layer during device fabrication. Reducing the thickness of CdS layer improves the QE in the blue spectral region without affecting the device performance. This buffer layer is expected to prevent the formation of localized TCO/CdTe junction during high temperature processing.

The CdS/CdTe Solar Cell was modified by introducing ZTO as a buffer layer between the window layer (CdS) and the absorber layer (CdTe). Studies were performed on different varying ZTO processing parameters like (a) Zn/Sn atomic ratios during sputtering process, …

Study Of Tin Oxide For Hydrogen Gas Sensor Applications, Manoj Anand

USF Tampa Graduate Theses and Dissertations

Tin oxide (SnO₂) has been investigated and used as a gas sensing material for numerous applications from the very start of the sensor industry. Most of these sensors use semiconductors (mostly SnO₂) as the sensing material.

In this work, SnO₂ was prepared using 2 techniques: firstly the MOCVD where we dope the sample with fluorine and secondly sputtering technique where samples are undoped in our case. These samples were tested at different conditions of temperature varying from room temperature to 150 degrees C, in ambient gas atmosphere of 200 CC Nitrogen (N₂).

The …

Modification Of Mdmx By Ubiquitination And Sumoylation, Yu Pan

USF Tampa Graduate Theses and Dissertations

MDM2 and MDMX are two major negative regulators of tumor suppressor p53. Both MDM2 and MDMX can inactivate p53 and play important roles in mouse embryonic development in a p53 dependent manner. MDM2 possesses ubiquitin E3 ligase activity and mediates self-ubiquitination as well as ubiquitination and degradation of p53 by proteasome. We identify MDMX as another ubiquitin E3 ligase substrate of MDM2. MDM2 promotes the ubiquitination and degradation of MDMX through proteasome pathway. The RING domains of both MDMX and MDM2 are required and sufficient for MDM2-mediated MDMX ubiquitination. ARF overexpression, DNA damage or MDM2 overexpression can all stimulate MDMX …

Development And Characterization Of Carbon Nanotubes For Sensor Applications, Jessica Eileen Otto

USF Tampa Graduate Theses and Dissertations

The aim of this research was to develop, characterize, and analyze carbon nanotubes as biosensors. In particular, pH and lactate molecules were targeted in this study. The reason these analytes were chosen was twofold. Firstly, when hydrogen ions and lactate are excreted in abnormal amounts in human sweat, they may be an indicator of a separate health problem. Thus, there is a clinical need for such biosensor applications. Secondly, pH and lactate detection represent two different types of electrochemical sensing techniques.

The carbon nanotubes used in this research were single walled and existed in bundles. They were further functionalized with …

Music Integration: Educators’ Perceptions Of Implementation And Student Achievement In Public School Elementary Education, Cynthia Marie Shuck

USF Tampa Graduate Theses and Dissertations

This qualitative case study investigated the levels and frequency of music integration being implemented at a public elementary school in central Florida, what key issues affect the successful implementation of effective music integration, and if music integration has an influence on academic achievement.

This study focused on 14 elementary school educators actively involved with music integration at one public elementary school. The multiple formats of data collection and analysis provided triangulation and increased the viability and transferability of the results. The five data collection formats that were used consisted of surveys, observations, lesson plans, interviews, and student achievement documents. Data …

Neurochemical Analysis Of Cocaine In Adolescence And Adulthood, Kirstie Helen Stansfield

USF Tampa Graduate Theses and Dissertations

Adolescence is a time of high risk behavior and increased exploration. This developmental period is marked by a greater probability to initiate drug use and is associated with an increased risk to develop addiction and dependency in adulthood. Human adolescents are predisposed toward an increased likelihood of risk taking behaviors (Zuckerman M, 1986), including drug use or initiation. The purpose of this study was to examine differences in developmental risk taking behaviors and neurochemical responsivity to cocaine based on these behavioral characteristics. Adolescent and adult animals were exposed to a novel stimulus in a familiar environment to assess impulsivity, novelty …

Effect Of Sno2 Roughness And Cds Thickness On The Performance Of Cds/Cdte Solar Cells, Lingeshwar Nemani

USF Tampa Graduate Theses and Dissertations

Textured SnO₂ films as TCO have been investigated to determine the effect of surface roughness on the performance of CdS/CdTe solar cells. Film roughness was controlled by varying the substrate temperature. Characterization of the SnO2 films has also carried out using AFM measurements. It was found that increase in substrate temperature results in increased roughness of the film.

A series of cells were fabricated with different CdS thicknesses to determine the combined effect of SnO₂ roughness and CdS thickness. As a part of fabrication process, cells were subjected to different post deposition treatments. It was observed that roughness …

County Level Predictors Of Homicide And Suicide In The State Of Florida, Kelly K. Browning

USF Tampa Graduate Theses and Dissertations

The present study expands the range of theoretical perspectives and empirical questions that have occupied the recent literature on homicide and suicide. The study examines county-level predictors for homicide and suicide in all sixty-seven counties in Florida. The current examination identifies which county-level variables are most closely related to each other, which variables explain the greatest amount of differences within the Florida counties, as well as which variables are most significantly correlated with the homicide and sucide rate by county. Additionally, the variables included in the present research are driven by the theorectical perspectives of social disorganization and anomie/strain theory. …

An Implementation Of The Usf/ Calvo Model In Verilog-A To Enforce Charge Conservation In Applicable Fet Models, Joshua Nicodemus

USF Tampa Graduate Theses and Dissertations

The primary goal of this research is to put into code a unique approach to addressing problems apparent with nonlinear FET models which were exposed by Calvo in her work in 1994. Since that time, the simulation software for which her model was appropriate underwent a significant update, necessitating the rewriting of her model code for a few applicable FET models in a Verilog-A, making it more compatible with the new versions of software and simulators.

The problems addressed are the inconsistencies between the small-signal model and the corresponding large-signal models due to a factor called transcapacitance. It has been …

The Effects Of Hand Fidgets On The On-Task Behaviors Of A Middle School Student With Disabilities In An Inclusive Academic Setting, Karen S. Voytecki

USF Tampa Graduate Theses and Dissertations

Many students with mild disabilities display off-task behaviors during academic content classes. The off-task behaviors can negatively impact their academic progress. In primarily clinical settings, specific interventions derived from the theory of sensory integration have been shown to increase on-task behaviors in students with mild disabilities. Using a single subject A-B-A-B withdrawal design, the researcher investigated the effects of hand fidgets on on-task behaviors demonstrated by a middle school student with mild disabilities who typically displayed off-task behaviors when participating in an inclusive, academic content class (language arts). Social validity was assessed to evaluate student and teacher perceptions regarding the …

Two Essays On Security Offerings: Information Production, Investor Perception And The Types Of External Financing, And A Unified Analysis On Financing Choices And Offering Costs, Bingsheng Yi

USF Tampa Graduate Theses and Dissertations

I investigate the impacts that information production, information asymmetry have on firms financing choices 3/4 equity financing or debt financing. I find that equity issue announcements encourage more information production than debt issue announcements, which in turn raises the probability of equity financing. In addition, the post-issue stock market performance is positively associated with information production. The results are robust after controlling for investor optimism. I also apply the Heckmans two-step procedure to jointly investigate firms financing choices and offering costs. I find that security-issuing firms choose the less-costly financing type.

Examining A Framework Of Dialogue E-Mails And Inquiry Into Practice To Scaffold Reflective Practice In Preservice Teachers During Their Early Field Experience, Susan L. Lloyd

USF Tampa Graduate Theses and Dissertations

This qualitative study focused on the development of reflective practice with preservice teachers through a framework during an early field experience. The framework provided an explicit structure for the preservice teachers to investigate four focus areas (teachers role, active learning, culture, and assessment). The preservice teachers explored a focus area, dialogued via e-mail with a peer, and then discussed their findings in small groups.

The preservice teachers were given a pre and post survey that queried them about their beliefs related to the four focus areas and the concept of reflection. Content analysis of the explanatory statements on the survey, …

The Effects Of A Parent Intervention On The Phonological Awareness Skills Of Kindergarten Students, Andrea Ofiara

USF Tampa Graduate Theses and Dissertations

This study examined the efficacy of the Sound Foundations program, implemented by parents, for increasing phonological awareness (PA). Three kindergarten students identified with PA deficits and their mothers served as participants. Parents implemented Sound Foundations twice per week for five and a half weeks. The effects of the intervention were evaluated using a multiple baseline across participants design. PA was measured using the Phoneme Segmentation Fluency measure of the Dynamic Indicators of Basic Early Literacy Skills. Results showed that two students showed increases over time in phonemes per minute after the parent intervention. A third student did not show substantial …

Computation Of Fluid Circulation In A Cryogenic Storage Tank And Heat Transfer Analysis During Jet Impingement, Santosh Kumar Mukka

USF Tampa Graduate Theses and Dissertations

The study presents a systematic single and two-phase analysis of fluid flow and heat transfer in a liquid hydrogen storage vessel for both earth and space applications.The study considered a cylindrical tank with elliptical top and bottom. The tank wall ismade of aluminum and a multi-layered blanket of cryogenic insulation (MLI) has been attached on the top of the aluminum. The tank is connected to a cryocooler to dissipate the heat leak through the insulation and tank wall into the fluid within the tank. The cryocooler has not been modeled; only the flow in and out of the tank to …

Ammonium, Nitrate, And Nitrite In The Oligotrophic Ocean: Detection Methods And Usefulness As Tracers, Robert T. Masserini Jr.

USF Tampa Graduate Theses and Dissertations

The overall focus of this research was to achieve the first detailed understanding of temporal and geographical distributions of inorganic-nitrogen-nutrients within an oligotrophic euphotic zone. In addition to low supply of nutrients, the uptake of nutrients by phytoplankton within the euphotic zone draws the nutrient concentrations down, resulting in very low concentrations of these nutrients and results in these regions being classified as oligotrophic. The site selected for the research was the West Florida Shelf (WFS). There were two main challenges. One was that the detection limits of the standard chemistries used to determine inorganic nitrogen nutrients are not low …

The Effects Of The Presence Of A Dog On The Social Interactions Of Children With Developmental Disabilities, Stephanie Walters

USF Tampa Graduate Theses and Dissertations

The effects of the presence of a dog on the social interactions between children with developmental disabilities and their teacher were analyzed in this study. We examined whether the presentation of a dog would improve the social interactions of three children with developmental disabilities. A baseline condition consisting of the child and teacher in the presence of three toys, one of which was a toy dog was followed by an intervention in which a real dog was added to the sessions. A multiple baseline design across participants was employed to assess experimental changes in interactions during the intervention condition.

All …

Disentangling The Repurchase Announcement An Event Study Analysis To The Purpose Of Repurchases, Robin S. Wilber

USF Tampa Graduate Theses and Dissertations

Researchers have consistently shown that a firms repurchase announcement is met with positive abnormal stock price return reactions. Open-market repurchases are extremely flexible, non-committal and non-punitive; thus, it is puzzling that the mere announcement of an open-market repurchase will likely increase a firms stock price. I propose to disentangle a firms choice to repurchase its stock to determine when a repurchase announcement is good news for shareholders and when the announcement is not.

I find that the purpose of the repurchase announcement matters. At the announcement date, managers intention of avoiding dilution is significantly negative and enhancing shareholder value is …

Design And Evaluation Of A New Authentication Mechanism For Validating The Sender Of An Email, Sai Sakamuri

USF Tampa Graduate Theses and Dissertations

A new authentication mechanism for validating the source of messages over the Internet is designed and evaluated. This mechanism is applied to email and is called Email++. Email++ prevents identity forging (spoofing) and tampering of email contents. By preventing identity forging, Email++ can reduce the amount of spam received and limit the spread of viruses like Melissa, Love Bug, Bagle Worm, and Killer Resume. Email++ validates both the sender and the receiver of an email by confirming the senders identity with the domain mail server that delivered the email for the sender, and authenticates the receiver with hash value comparisons. …

Giving Voice To Parents Of Young Children With Challenging Behavior, Jonathan Worcester

USF Tampa Graduate Theses and Dissertations

In recent years, there has been increased interest in the science of child development, particularly relative to early childhood (i.e., birth to 5 years) and children with challenging behavior. A broad interest in brain-behavior relationships and prevention services for young children has led to a renewed interest in the developmental significance of early life experiences (National Research Council and Institute of Medicine, 2000). Armed with an increasingly large body of neuroscience research, researchers have begun to examine the efficacy of prevention services and supports for young children and families, particularly those with challenging behavior (i.e., behaviors that interfere with optimal …