Physical Sciences and Mathematics Commons^™

Formulation To Application: Thermomechanical Characterization Of Flexible Polyimides And The Improvement Of Their Properties Via Chain Interaction, Alejandro Rivera Nicholls

USF Tampa Graduate Theses and Dissertations

In this work, Polyimides were synthesized by incorporating an aromatic diamine monomer with a methylene linker, 4,4'-methylenebis(2,6-dimethylaniline) (MBDMA), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to reduce rigidity. The polymers were designed to exhibit thermal properties in between those of conventional aromatic polyimides and polymers with wholly aliphatic ether diamine links. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that control of the molar ratios of the aromatic MBDMA and the composition and size of the aliphatic polyetherdiamine can be used to tune the glass transition temperature. The materials were characterized and …

Effects Of Reservoir Conditions And Trace Co-Contaminant Gases On Geological Carbon Sequestration, Ram Kumar

USF Tampa Graduate Theses and Dissertations

Geological carbon sequestration in a saline formation is a promising technology for large-scale carbon dioxide (CO2) mitigation. Several factors such as temperature, pressure, salinity, hydraulic conductivity, and mineralogy of a formation affect the CO2 sequestration in saline formations. These factors can vary widely depending upon the type of formation or the degree of heterogeneity within a formation. In addition to these properties of the repositories, the CO2-rich flue gas streams captured from point sources often contains small amounts of impurities such as sulfur oxides (SOx) and nitrogen oxides (NOx), which may have serious implications on the chemistry of the repositories …

Evaluating Conversation Agent Impact On Student Experience In A Distance Education Course, Grover Walters

USF Tampa Graduate Theses and Dissertations

We explore the efficacy of conversation agents operating as an instructional aid in a distance education course. Two aspects of efficacy are considered—conversation agent impact on student perceptions of the experience, and how different design features of the agent affect student perceptions of engagement. Evaluation of the agent is accomplished by collecting data from 24 undergraduate participants separated into random groups. We conduct two rounds of mixedmethod evaluation. Between the two rounds, a modification to the agent occurs based on the outcome of the first evaluation. Findings include limitations related to phrasing and data persistence features of the design that …

Fabrication And Characterization Of Electrical Energy Storage And Harvesting Energy Devices Using Gel Electrolytes, Belqasem Aljafari

USF Tampa Graduate Theses and Dissertations

Redox-active materials in the bulk of gel electrolytes are unquestionably holding the primary roles in developing energy harvesting and storage technology. Both technologies are necessary in order to cope with the current challenges of the environmental crises of global warming and finite non-renewable sources while the demand for energy modern societies have been speedily increased. One of the most challenges of making a hybrid device of energy conversion and storage is the cost of the fabrication process. Therefore, gel electrolyte-based materials with redox-active properties can potentially be a promising solution to improve the performance of electrochemical and photoelectrochemical devices for …

Desertification Risk Analysis Based On Soils And Climate In Olive Cultivated Areas In Tulare County, California, Zehra Kavakli Karatas

USF Tampa Graduate Theses and Dissertations

Desertification is one of the most critical environmental problems caused by human activities and climate change. As a result of human activities, land degradation has been seen in many agricultural areas. Intense pressure on cultivated fields causes loss of soil fertility, which can then lead to desertification. Planting plant drought-resistant plants, such as olives, is one strategy for reducing desertification risk in cultivated areas. It is essential to find a way not only how to combat this process but also how to adapt or survive with desertification conditions. Defining desertification risks have a fundamental role in combating drought. The goal …

Boron Variation And The Subducted Sediment Component In The Volcanics From The Bifurcated Portion Of The Lesser Antilles Island Arc (Laia), Ami Margret Ngo Ward

USF Tampa Graduate Theses and Dissertations

North of Martinique island the Lesser Antilles volcanic arc bifurcates, creating a double arc. Here volcanic activity has migrated up to 50 km westward with time, resulting in two volcanic lines that are distinct in age. The eastern line, commonly referred to as the old arc, was active from Early Eocene to Mid-Miocene (Nagle, 1971; Nagle et al., 1976; Westercamp and Tazieff, 1980; Andreieff et al., 1988). The western line, commonly referred to as the recent arc, has been active since the late Pliocene, ~6 Ma ago (Nagle, 1971; Nagle et al., 1976; Westercamp and Tazieff, 1980; Andreieff et al., …

Fractional Random Weighted Bootstrapping For Classification On Imbalanced Data With Ensemble Decision Tree Methods, Sean Charles Carter

USF Tampa Graduate Theses and Dissertations

Ensemble methods are commonly used for building predictive models for classification. Models that are unstable to perturbations in the training set, such as the decision tree, often see considerable reductions in error when grouped, using bootstrapped resamples of the training data to train many models. The non-parametric bootstrap, however, has limited efficacy when used on severely imbalanced data, especially when the number of observations of one or more classes is exceptionally small. We explore the fractional random weighted bootstrap, which randomly assigns fractional weights to observations, as an alternative resampling pro cedure in training machine learning ensembles, particularly decision tree …

Can Florida's Springs Coast Provide A Potential Refuge For Calcifying Organisms? Evidence From Benthic Foraminifera, Kyle E. Amergian

USF Tampa Graduate Theses and Dissertations

Florida’s Springs Coast, located in the northeast Gulf of Mexico, includes an extensive system of salt marshes that discharge millions of liters of fresh water into coastal waters daily. The chemical properties of the spring waters include high alkalinity and high calcium concentrations due to the Paleogene limestone lithology of this region of Florida. Benthic foraminifers, which are recognized as ecologically important bioindicators, occur abundantly on the shallow shelf off the Springs Coast. Based on the prevalence of the benthic foraminifer Archaias angulatus in the seagrass beds along this shallow shelf, a previous study proposed that the Springs Coast provides …

Measuring And Utilizing High-Dimensional Information Of Optical Fields, Ziyi Zhu

USF Tampa Graduate Theses and Dissertations

Currently, many areas of optical techniques including imaging, inspection and communication emphasize the utilization of the high-dimensional information encoded in optical fields. There is also a requirement for novel measurement techniques to extract this high-dimensional information with high-speed and accuracy. We firstly introduce a scan-free direct measurement technique that is capable of simultaneously characterizing the amplitude and phase of a coherent scalar optical field. Our direct measurement approach is constituted of a weak polarization perturbation which is followed by the recording of a polarization-resolving imaging process. The weak perturbation rotates the linear polarization on the spatial frequency domain of the …

Evaluating The Evidence Base For Evidence-Based Instructional Practices In Chemistry Through Meta-Analysis, Md Tawabur Rahman

USF Tampa Graduate Theses and Dissertations

Investigating the effectiveness of instructional practices provides an evidence base to inform instructional decisions. Synthesizing research studies on instructional effectiveness provides an estimate of the generalizability of effectiveness across settings, along with an exploration of factors that may moderate the impact, which cannot be achieved within individual studies. This study sought to provide a synthesis of evidence- based instructional practices (EBIPs) particular to chemistry through meta-analysis. 99 studies were analyzed comprising a broader view of chemistry specific studies than past meta-analyses. The results showed that EBIPs feature a demonstrably positive impact on students’ academic performance in chemistry, although assessment topic …

Thermo-Oxidative Degradation Of Hdpe Geomembranes: Effect Of Phenolic Antioxidant And Hindered Amine Light Stabilizer Concentrations, Yasin Kocak

USF Tampa Graduate Theses and Dissertations

High density polyethylene (HDPE) geomembrane is most common geomembrane which is mainly used for civil engineering applications. However, HDPE geomembrane loses its properties under oxidative degradation progress. This study aims to assess geomembranes which have different percentage of phenolic antioxidant and hindered amine light stabilizer (HALS) with under the six months of the thermal-oxidative degradation. The interactions between phenolic antioxidant, HALS and carbon black can affect the mechanical, physical and chemical properties. To monitor these properties, Differential Scanning Calorimetry (DSC), Fourier-transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM/EDX), Melt Index tests, …

Life History Through The Eyes Of A Hogfish: Evidence Of Trophic Growth And Differential Juvenile Habitat Use, Meaghan E. Faletti

USF Tampa Graduate Theses and Dissertations

Understanding ontogenetic linkages among fish habitats is critical for conservation of fish populations and the ecosystems on which they rely. Natural tags such as stable isotopes are an effective tool commonly used to investigate ecological questions regarding fish movement and habitat use. Here, I analyzed stable isotopes from the sequentially deposited laminae of Hogfish (Lachnolaimus maximus) eye lenses from the eastern Gulf of Mexico (eGOM) to investigate trophic and geographic changes across individual life histories. I documented evidence of entire-life scale trophic growth through increases in δ15N. I also observed depth separation at the juvenile stage, evidenced by variation in …

Detecting Digitally Forged Faces In Online Videos, Neilesh Sambhu

USF Tampa Graduate Theses and Dissertations

We use Rossler’s FaceForensics dataset of 1004 online videos and their corresponding forged counterparts [1] to investigate the ability to distinguish digitally forged facial images from original images automatically with deep learning. The proposed convolutional neural network is much smaller than the current state-of-the-art solutions. Nevertheless, the network maintains a high level of accuracy (99.6%), all while using the entire FaceForensics dataset and not including any temporal information. We implement majority voting and show the impact on accuracy (99.67%), where only 1 video of 300 is misclassified. We examine why the model misclassified this one video. In terms of tuning …

Fewer Wetlands More Connectivity: Implications Of Land Use-Land Cover Change In An Agricultural Landscape, Stephanie Lawlor

USF Tampa Graduate Theses and Dissertations

St. Lucie County (SLC) is a 1,782 km2 area in east-central Florida that drains to the Nationally Significant Indian River Lagoon (IRL). It is low lying and nearly level, with widespread non-floodplain wetlands (NFWs) and few natural channels. NFWs comprise the vast majority of SLC wetlands, both in terms of numbers and area. Since the early 20th century, SLC has undergone extensive land use-land cover (LULC) change and is now characterized by citrus farming in the interior and municipalities on its eastern coast on the Atlantic Ocean. This LULC change has been made possible by the construction of an extensive …

Interactive Fitness Domains In Competitive Coevolutionary Algorithm, Atm Golam Bari

USF Tampa Graduate Theses and Dissertations

Evolutionary Algorithms (EA) have been successfully applied to a wide range of optimization and search problems where no mathematical model of the quality of a candidate solution is available. Interactive Evolutionary Algorithms (IEA) and Competitive Coevolutionary Algorithms (CCoEA) go one step further by being able to tackle problems where the only means to evaluate the quality of a candidate solution is via interactions. In a typical IEA, interactions take place between the solution being evolved and human evaluators. In a CCoEA, interactions take place between solutions themselves, without need for human interaction. This dissertation identifies computer-aided learning as an application …

Energy Transition Modeling: Social And Technical Dynamics Of Moving To Renewable Energy, Lawrence Gottschamer

USF Tampa Graduate Theses and Dissertations

The majority of global electricity is generated using fossil fuels as an energy source, and the science linking fossil fuel combustion with negative environmental impacts is clear. Recognizing this link, decarbonizing the electricity system is a critical component of climate change mitigation. However, moving electricity generation, distribution, and end-use behavior patterns to renewable energy is a complex socio-technical energy transition challenge with a number of economic, policy, technological, societal and environmental barriers. Energy transition work tends to be siloed within these topics; ignoring complex socio-technical interdependencies impacting electricity system transition dynamics. This work fills the knowledge gap with a ‘systems …

Sundaas Story: A Mixed-Methods Study Of Household Sanitation Provisioning In Urban Informal Housing In India, Sarita Vijay Panchang

USF Tampa Graduate Theses and Dissertations

The aims of this research were to examine sanitation insecurity in urban informal housing through the lens of the built environment, social disparities, and health implications. While the Millennium Development Goals for halving the global proportion of people without access to safe drinking water were met ahead of schedule, progress fell short for sanitation, creating new objectives for the Sustainable Development Goals to be met in 2030. Much research in the Global South is dedicated to community-level sanitation promotion, but often presumes a rural rather than urban setting. Urban informal housing settings constitute a unique challenge due to the range …

Modeling Of Buildings With Electrochromic Windows And Thermochromic Roofs, Hua-Ting Kao

USF Tampa Graduate Theses and Dissertations

Air conditioning and heating have increased substantially during the past two decades. According to a survey, buildings consume about 73% of the total electricity in the United States, accounting for 41% of all other energy in the world. At the same time, building skin technologies are constantly improving. Electrochromic and thermochromic are two exciting new technologies that can help reduce the energy consumption of a building. The purpose of this work is to increase our understanding of how much the use of electrochromic (EC) and thermochromic (TC) technologies can reduce the energy consumption of residential and commercial buildings in two …

On Automation Of Code Transformations For Concept Inventory Misconceptions, Dmytro Vitel

USF Tampa Graduate Theses and Dissertations

Identifying common misconceptions held by novice programmers is a primary goalof the Computing Education Research agenda. This thesis proposes to formalize such mis-conceptions through program transformations. We first describe the implementation of theEvoParsons system, that allows students to practice programming skills with the help ofso-called Parsons puzzles. This software serves as a tool for gathering data on how studentsinteract with such puzzles. Our first contribution is the system architecture reorganization:development of Web SPA UI, REST service back-end, hypothesis validation infrastructureand student-UI data collection. We then review and compare several code-transformationtools (ANTLR, Rascal MPL and StrategoXT) and show how they might …

A Communication-Centric Framework For Post-Silicon System-On-Chip Integration Debug, Yuting Cao

USF Tampa Graduate Theses and Dissertations

System-on-Chip (SoC) plays an important role in people’s everyday life. These systems are often deployed in critical applications, bugs discovered after their deployment in field can be extremely expensive, resulting in catastrophic loss of company revenues, compromise of personal and national security, and even human life. Post-silicon debug is a critical component of the validation of modern microprocessors and SoC designs. A major challenge in post-silicon debug is the severely limited observability where only a small number of debug interface signals are available to observe a vast space of internal executions of SoC designs. This dissertation addresses the above issues …

Authentication Usability Methodology, Jean-Baptiste Subils

USF Tampa Graduate Theses and Dissertations

Nowadays many systems require end users to authenticate themselves. Authentication is one of the security activities that end users perform the most. Thus, the usability of this security feature plays a major role in the proper utilization and adoption of a novel authentication method.

This dissertation presents coauthentication, a novel authentication system. Many authentication methods and protocols exist, but passwords remain the predominant authentication method used. Coauthentication is presented here in detail in several possible variations and their associated protocols, with performance comparisons.

This dissertation also presents a framework to evaluate authentication methods in terms of usability.

A large body …

A Gpu-Based Framework For Parallel Spatial Indexing And Query Processing, Zhila Nouri Lewis

USF Tampa Graduate Theses and Dissertations

Support for efficient spatial data storage and retrieval have become a vital component in almost all spatial database systems. Previous work has shown the importance of using spatial indexing and parallel computing to speed up such tasks. While GPUs have become a mainstream platform for high-throughput data processing in recent years, exploiting the massively parallel processing power of GPUs is non-trivial. Current approaches that parallelize one query at a time have low work efficiency and cannot make good use of GPU resources. On the other hand, many spatial database applications are busy systems in which a large number of queries …

Multimodal Emotion Recognition Using 3d Facial Landmarks, Action Units, And Physiological Data, Diego Fabiano

USF Tampa Graduate Theses and Dissertations

To fully understand the complexities of human emotion, the integration of multiple physical features from different modalities can be advantageous. Considering this, this thesis presents an approach to emotion recognition using handcrafted features that consist of 3D facial data, action units, and physiological data. Each modality independently, as well as the combination of each for recognizing human emotion were analyzed.

This analysis includes the use of principal component analysis to determine which dimensions of the feature vector are most important for emotion recognition. The proposed features are shown to be able to be used to accurately recognize emotion and that …

On The Ablation Of Meteors And The Implications On Organic Delivery To Earth, Christopher Alan Mehta

USF Tampa Graduate Theses and Dissertations

The synthesis of prebiotic organic compounds is a key step in the origin of life. Sources of these materials are divided into endogenous and exogenous sources. Endogenous synthesis—occurring potentially on the surface of the Earth—includes such historic experiments as the Miller spark discharge and formose chemistry. However, one avenue for exogenous synthesis to occur is when meteors enters an atmosphere. Using principles of orbital mechanics, geology, physics, and chemistry, we study meteor ablation and the transport of organic matter to the surface of Earth. To do so, I create numerical models that simulates meteors traveling through the atmosphere of Earth …

Experiences Of Using Intelligent Virtual Assistants By Visually Impaired Students In Online Higher Education, Michele R. Forbes

USF Tampa Graduate Theses and Dissertations

In today’s world, the attainment of higher education impacts the acquisition of competitive employment and, thus, quality of life. As a group, persons with disabilities continually fall behind others in such academic progress, requiring new efforts to support their earning of advanced credentials. Though highly beneficial for these individuals, obtaining a degree comes with elevated levels of stress. As enrollment of students with disabilities grows in all formats of higher education, those involved must understand the stress endured by these students and how to diminish it. Theories speculate that technology, such as intelligent virtual assistants, may be a viable tool …

Probabilistic Modeling Of Democracy, Corruption, Hemophilia A And Prediabetes Data, A. K. M. Raquibul Bashar

USF Tampa Graduate Theses and Dissertations

Parametric analysis of any real-world data is the most powerful tool to characterize the probabilistic behavior in social, economic, medical, epidemiological, and other areas of study. In the present study, we identify the theoretical Probability Distribution Function(PDF) for Democracy Index Scores (DIS) from the Economist Intelligence Unit (EIU) database and estimate the maximum likelihood estimates of the theoretical PDFS. We also identify the individual PDFs for each of the clusters, Full Democracy, Flawed Democracy, Hybrid Regime, and Authoritarian Regime defined by the Economist Intelligence Unit (EIU).

A statistical model is a convenient instrument to predict the future value of any …

Design And Implementation Of Degenerate Qpcr/Qrt-Pcr Primers To Detect Microbial Nitrogen Metabolism In Wastewater And Wastewater-Related Samples, Ryan F. Keeley

USF Tampa Graduate Theses and Dissertations

Nitrogen cycling processes can be tracked using quantitative Polymerase Chain Reaction (qPCR) to determine the presence and qReverse Transcriptase-PCR (qRT-PCR) to determine expression of key genes, or ‘biological markers’, for nitrogen metabolism. Nitrification is catalyzed in part, by two enzymes: ammonia monooxygenase (AMO; NH3 NH2OH) and nitrite oxidoreductase (NXR; NO2- NO3-). For denitrification, four enzymes act sequentially: nitrate reductase (NAR/NAP; NO3- NO2-), nitrite reductase (NIR; NO2- NO), nitric oxide reductase (NOR; NO  N2O), and nitrous oxide reductase (NOS; N2O  N2). A principle of wastewater treatment (WWT) is to remove excess nitrogen by taking advantage of natural nitrogen cycling …

Fluid-Mobile Trace Element Variability Of Serpentinites And Entrained Crustal Rocks Across The Mariana Forearc System, Raymond M. Johnston

USF Tampa Graduate Theses and Dissertations

In the Mariana subduction system, active serpentinite mud volcanoes are associated with the subduction of the Pacific plate beneath the Philippine plate in a non-accretionary convergent plate margin. This location offers a unique opportunity to study the subduction zone interface with little crustal contamination. The systematics of fluid-mobile trace elements (FME) (As, Cs, Rb, Sb, Tl, Pb, and Sr) in erupted serpentinite muds and entrained serpentinized ultramafic and mafic clasts can place constraints on the release of slab-derived fluids from the downgoing plate, and ultimately the pressure/temperature (P/TC°) conditions at which these fluids are mobilized.

The samples analyzed in this …

Population Demographics Of Golden Tilefish Lopholatilus Chamaeleonticeps In The Gulf Of Mexico, Greta J. Helmueller

USF Tampa Graduate Theses and Dissertations

The Deepwater Horizon (DWH) oil spill had catastrophic impacts on aquatic organisms in the Northern Gulf of Mexico (GoM). Longline gear was used to sample demersal fish species at 344 locations distributed throughout the GoM in the seven years following DWH. Sampling was accomplished deploying 450-500 baited hooks per station in depths ranging from 20-600 m. Using data from these surveys, I analyzed the length and age frequency, condition, growth, and mortality rates of Golden Tilefish (Lopholatilus chamaeleonticeps) throughout the GoM. Demersal habitat use and apparent high contaminant levels in Golden Tilefish makes them potentially vulnerable to oil spills such …

An Exploration Of Turkish Kindergarten Early Career Stage Teachers’ Technology Beliefs And Practices, Ozge Ozel

USF Tampa Graduate Theses and Dissertations

The purpose of this study was to explore Turkish kindergarten early career stage teachers’ self-efficacy beliefs towards technology and their technology integration practices in their classrooms by answering: What are self-efficacy beliefs of Turkish kindergarten early career stage teachers towards technology? How do Turkish kindergarten early career teachers integrate technology into their classrooms’ instructions? The study was designed as a qualitative multiple case study and guided by Bandura’s (1986) social cognitive theory and Mishra and Koehler’s (2006) TPACK conceptual framework. I conducted this study in Istanbul, where is the most crowded and metropolitan city in Turkey. The schools were chosen …