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Bio-Inspired Design, Fabrication And Testing Of Bipolar Plates For Pem Fuel Cells, Nannan Guo

Doctoral Dissertations

"The flow field of a bipolar plate distributes reactants for polymer electrolyte membrane (PEM) fuel cells and removes the produced water from the fuel cells. It greatly influences the performance of fuel cells, especially the concentration losses. Two approaches were developed to improve flow field designs in this dissertation. One is inspired by the biological circulatory structures and called bio-inspired designs, which have great potential to transport reactant efficiently and hence improve fuel cell performance. Another way is using a network-based optimization model to optimize the conventional flow field configurations, i.e., pin-type, parallel and serpentine designs, to improve flow distributions …

A Biocompatible Sic Rf Antenna For In-Vivo Sensing Applications, Shamima Afroz

USF Tampa Graduate Theses and Dissertations

A continuous glucose sensor employing radio frequency (RF) signals is presented using the biocompatible material Silicon Carbide (SiC). Unlike biosensors that require direct contact with interstitial fluids to trigger chemical reactions to operate, this biocompatible SiC sensor does not require a direct interface. The sensing mechanism for this SiC sensor is based upon a shift in resonant frequency, as a function of change in glucose levels, which electrically manifests itself as a change in blood permittivity and

conductivity. For in vivo applications the antenna sensor needs to operate inside the body environment, and it has been found that the best …

Slowing The Onset Of Hypoxia Increases Colony Forming Efficiency Of Connective Tissue Progenitor Cells In Vitro, Christopher M. Heylman, Tonya N. Caralla, Cynthia A. Boehm, Thomas E. Patterson, George F. Muschler

Biomedical Engineering

Background: Survival and colony formation by transplanted tissue derived connective tissue progenitor cells (CTPs) are thought to be important factors in the success of clinical tissue engineering strategies for bone regeneration. Transplantation of cells into defects larger than a few millimeters expose cells to a profoundly hypoxic environment. This study tested the hypothesis that delaying the onset of hypoxia will improve the survival and performance of CTPs in vitro.

Methods: To mimic declines seen in an avascular in vivo bone defect, colony forming efficiency by marrow derived nucleated cells was assessed under osteogenic conditions. Variation in the rate of …

Evaluation Of Chemical Additives For The Separation And Recovery Of Bacteria From Food Matrices, Jennifer Leanne Frederick, Stephen P. Walker, Czarena L. Crofcheck, Melissa Newman, Frederick Payne

Biosystems and Agricultural Engineering Faculty Publications

The microbiological testing of foods is a well-established science. Due to the severity of foodborne pathogen illnesses, the widespread use and implementation of rapid detection methods in food testing labs is increasingly important. The first step for successful testing is sampling. Surfactants have been widely used in food microbiology, but there is not much, if any, published research about the use of fatty alcohols and chemical dispersants as aids in microbial separation and recovery. The microbial extraction efficiency of Escherichia coli K12 and Listeria innocua from three representative food matrices (hot dogs, spinach, and milk) was measured using chemical additives …

Quantitative Analyses Of Acceptable Noise Level For Air Conduction Listening, Bankole K. Fasanya

Dissertations

This study was conducted to develop quantitative models for Acceptable Noise Level (ANL) under air conduction (AC) listening conditions. Experimental results on the effects of frequency bandwidths on ANL under two listening conditions involving earphones and loudspeaker (sound field) with high and low frequencies and babble noise and white noise revealed: (a) there are statistically significant interactions among the background noise types, the background noise frequency bandwidths and signal source; (b) background noise and noise frequency bandwidths have effects on listener discriminability bias toward the noise and the signal intensity; (c) different listening conditions had different ANL thresholds; and (d) …

Bio-Inspired Cooperative Optimal Trajectory Planning For Autonomous Vehicles, Charles Remeikas

Electronic Theses and Dissertations

With the recent trend for systems to be more and more autonomous, there is a growing need for cooperative trajectory planning. Applications that can be considered as cooperative systems such as surveying, formation flight, and traffic control need a method that can rapidly produce trajectories while considering all of the constraints on the system. Currently most of the existing methods to handle cooperative control are based around either simple dynamics and/or on the assumption that all vehicles have homogeneous properties. In reality, typical autonomous systems will have heterogeneous, nonlinear dynamics while also being subject to extreme constraints on certain state …

The Effect Of Curriculum Organization On The Acquisition Of Abstract Declarative Knowledge In Computer Based Instructions., Saleh Al-Foraih

Electronic Theses and Dissertations

The United States of America has dropped behind many countries in terms of the Science and Engineering university degrees awarded since the beginning of the nineties. Multiple studies have been conducted to determine the cause of this decline in degrees awarded, and try to reverse the trend in US education. The goal of these studies was to determine the proper instructional methods that facilitate the knowledge acquisition process for the student. It has been determined that not one method works for all types of curriculum, for example methods that have been found to work effectively in curriculum that teaches procedures …

Effects Of Acute Stretch On Cardiac Electrical Properties In Swine, Anuj Agarwal

Theses and Dissertations--Biomedical Engineering

Stretch is known to result in an electrically less stable ventricular substrate, yet the reported effects of stretch on measured electrophysiological parameters have been inconsistent and even contradictory. The goal of this study was to evaluate the effects of acute mechanical stretch on cardiac electrical features thought to be key in generation of arrhythmia, namely restitution of action potential duration (APD), electrical memory, and onset of alternans.

Microelectrodes were used to record intracellular potentials pre, during, and post-stretch from isolated right ventricular tissues from swine. In separate experiments, the effects of two levels of stretch were quantified. Pacing protocols employing …

Hysteresis In Repolarization Of Cardiac Action Potentials: Effects Of Spatial Heterogeneity And Slow Repolarization Currents, Linyuan Jing

Theses and Dissertations--Biomedical Engineering

Repolarization alternans, i.e. beat-to-beat variation of repolarization of action potential, is proposed as a predictor of life-threatening arrhythmias. Restitution relates repolarization duration with its previous relaxation time, i.e. diatstolic interval (DI), and is considered a dominant mechanism for alternans. Previously, we observed that different repolarization durations at the same DI during decelerating and accelerating pacing, i.e. restitution displays hysteresis, which is a measure of “cardiac memory”.

Objective of the current study was to investigate in the pig 1) the mechanism for a previously observed hysteresis type phenomenon, where alternans, once started at higher heart rate, persists even when heart rate …

Development Of A Multilayered Association Polymer System For Sequential Drug Delivery, Sharath Kumar Chinnakavanam Sundararaj

Theses and Dissertations--Biomedical Engineering

As all the physiological processes in our body are controlled by multiple biomolecules, comprehensive treatment of certain disease conditions may be more effectively achieved by administration of more than one type of drug. Thus, the primary objective of this research was to develop a multilayered, polymer-based system for sequential delivery of multiple drugs. This particular device was designed aimed at the treatment of periodontitis, a highly prevalent oral inflammatory disease that affects 90% of the world population. This condition is caused by bacterial biofilm on the teeth, resulting in a chronic inflammatory response that leads to loss of alveolar bone …

Growth Plate Regeneration Using Polymer-Based Scaffolds Releasing Growth Factor, Amanda Clark

Theses and Dissertations--Biomedical Engineering

Currently growth plate fractures account for nearly 18.5% of fractures in children and can lead to stunted bone growth or angular deformation. If the body is unable to heal itself a bony bar forms, preventing normal bone growth. Clinical treatment involves removing the bony bar and replacing it with a filler substance, which causes poor results 60% of the time.

Using primarily poly(lactic-co-glycolic acid) (PLGA) as the scaffold material, the goal was to develop an implant that would support to the implant site, allow for cell ingrowth, and degrade away over time. Porous scaffolds were fabricated from PLGA microspheres using …

Development Of A Constitutive Model Of Compacted Shales And Determination Of The Effect Of Weathering On Its Parameters, Isabel Cristina Gomez-Gutierrez

Theses and Dissertations--Civil Engineering

Compacted shales cause problems because they tend to degrade with time due to weathering. Degradation results in the shale deteriorating from a hard rock-like material to a soft fine-grained soil mass with lower shear strength and high deformability. Consequently, common problems that occur in embankments constructed with compacted shales include settlement and instabilities. Therefore, accelerating weathering prior to compaction by wetting and breaking down the shales before placement can reduce the deterioration during the service life of the construction. Extensive laboratory testing was performed in order to characterize the mechanical behavior of compacted shales.

Critical State theory is a clever …

Investigation Of Media Ingredients And Water Sources For Algae Co2 Capture At Different Scales To Demonstrate The Correlations Between Lab-Scale And Large-Scale Growth, Tabitha Graham

Theses and Dissertations--Biosystems and Agricultural Engineering

As energy use increases globally the environmental burdens increase alike. Many accusations have been made that carbon dioxide is a culprit of climate change. The University of Kentucky and Duke Energy Power have partnered to test carbon capture technology in a large scale project. To this end, the objective of this thesis is to investigate potential water media sources and nutrient sources at different volume scales for algae cultivation to help create a more environmentally viable and economically feasible solution. This work will conduct a life cycle assessment of water media sources and the effects of the inputs and outputs …

Alkaline Hydrogen Peroxide Pretreatment For Its Use In An On-Farm Bioprocessing Facility, Mary Kathryn Gray

Theses and Dissertations--Biosystems and Agricultural Engineering

Pretreatment is an essential step in biofuel production from lignocellulose. Disruption of the lignin structure gives enzymes and fermentation organisms access to long chains of cellulose and hemicellulose. For this project’s purposes, the pretreatment must work within the framework of an on-farm butanol bioprocessing facility. Alkaline hydrogen peroxide (AHP) is a delignification method that potentially provides several advantages. At the alkaline pH, powerful hydroxyl radicals are formed; which attack lignin. The objectives of this study were to determine if AHP removes substantial lignin for the feedstocks, corn stover, wheat straw, switchgrass and miscanthus, and to determine if AHP acts as …

Nutrients Recycling Strategy For Microalgae-Based Co2 Mitigation System, Xinyi E

Theses and Dissertations--Biosystems and Agricultural Engineering

Coal-fired electricity production is the major emitter of CO₂ and other greenhouse gases including NO_x and SO_x. Microalgae-based CO₂ mitigation systems have been proposed to reduce the net CO₂ emission from coal-fired power plants. This study focused on developing an optimum culture media and exploring the possibilities for recycling nutrients, which were added as commercial mineralized chemicals at the beginning of cultivation.

In order to release the nutrients embedded in the cells so that they can be used as a nutrient source for new cells, Scenedesmus biomass was digested by anaerobic bacteria. Results showed …

A Framework For Understanding The Public's Perspectives Of Mining Applied To The Kentucky Coal Industry, Joshua M. Hoffman

Theses and Dissertations--Mining Engineering

People’s perceptions of mining are heavily based on the media they consume and the messages therein. News outlets ordinarily report on mining only when there is an accident or environmental concern. When messages that the public is exposed to are negative, it is no wonder that there are negative perceptions about mining.

Current public relations campaigns on the behalf of specific companies or select sectors do exist; however, this is often a reactionary move in response to recent shifts in the socio-political environment. The details of these campaigns are often tied up in proprietary information or withheld by public relations …

Enhanced Phosphate Flotation Using Novel Depressants, Lingyu Zhang

Theses and Dissertations--Mining Engineering

Froth flotation is the most efficient method for phosphate separation, which is a physic-chemical separation process based on the difference of surface properties between the valuable minerals and unwanted gangue minerals. However, the presence of clay slimes in the slurry after grinding consumes a large amount of reagents, decreases the collision probability between bubbles and minerals, prevents phosphate particle attachment to air bubbles, and thus considerably reduces flotation recovery and concentrate grade. Georgia Pacific Chemical, LLC has recently developed novel depressants, i.e., clay binders, which are a series of low molecular weight specialty polymers to help improve phosphate flotation performance …

Cerium Oxide (Ceo2) Promoted Oxygen Carrier Development And Scale Modeling Study For Chemical Looping Combustion, Fang Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

According to IPCC reports, the greenhouse gas CO₂ is responsible for global climate change. Studies show that CO₂ concentration reached a level of 400 ppm in 2013, or 40 % above pre-industrial levels. The contribution of CO₂ from industrial activity to increasing global CO₂ concentrations is widely accepted and points to the need to reduce the emission of this greenhouse gas.One possible combustion technology that shows promise for reducing CO₂ emissions is chemical looping combustion (CLC). It is an oxy-fuel technology, but has the advantages of in situ oxygen separation, low NO_x emissions and …

Chemophysical Characteristics And Application Of Biosorption Activated Media (Bam) For Copper And Nutrient Removal In Stormwater Management, Jamie Jones

Electronic Theses and Dissertations

For high groundwater table areas, stormwater wet detention ponds are utilized as the preferred stormwater management throughout the state of Florida. Previous research has found that accumulations of nutrients, algae, heavy metals, pesticides, chlorophyll a, fecal coliform bacteria and low concentrations of dissolved oxygen (DO) are common characteristics of stormwater wet detention ponds. Although these pollutant levels are not regulated within the ponds, states are required to compute the pollutant load reductions through total maximum daily load (TMDL) programs to meet the water quality requirements addressed by the Clean Water Act (CWA). In this study, field sampling data of stormwater …

Integrated Data Fusion And Mining (Idfm) Technique For Monitoring Water Quality In Large And Small Lakes, Benjamin Vannah

Electronic Theses and Dissertations

Monitoring water quality on a near-real-time basis to address water resources management and public health concerns in coupled natural systems and the built environment is by no means an easy task. Furthermore, this emerging societal challenge will continue to grow, due to the ever-increasing anthropogenic impacts upon surface waters. For example, urban growth and agricultural operations have led to an influx of nutrients into surface waters stimulating harmful algal bloom formation, and stormwater runoff from urban areas contributes to the accumulation of total organic carbon (TOC) in surface waters. TOC in surface waters is a known precursor of disinfection byproducts …

Routing, Localization And Positioning Protocols For Wireless Sensor And Actor Networks, Mustafa Akbas

Electronic Theses and Dissertations

Wireless sensor and actor networks (WSANs) are distributed systems of sensor nodes and actors that are interconnected over the wireless medium. Sensor nodes collect information about the physical world and transmit the data to actors by using one-hop or multi-hop communications. Actors collect information from the sensor nodes, process the information, take decisions and react to the events. This dissertation presents contributions to the methods of routing, localization and positioning in WSANs for practical applications. We first propose a routing protocol with service differentiation for WSANs with stationary nodes. In this setting, we also adapt a sports ranking algorithm to …

Bio-Inspired, Varying Manifold Based Method With Enhanced Initial Guess Strategies For Single Vehicle's Optimal Trajectory Planning, Ni Li

Electronic Theses and Dissertations

Trajectory planning is important in many applications involving unmanned aerial vehicles, underwater vehicles, spacecraft, and industrial manipulators. It is still a challenging task to rapidly find an optimal trajectory while taking into account dynamic and environmental constraints. In this dissertation, a unified, varying manifold based optimal trajectory planning method inspired by several predator-prey relationships is investigated to tackle this challenging problem. Biological species, such as hoverflies, ants, and bats, have developed many efficient hunting strategies. It is hypothesized that these types of predators only move along paths in a carefully selected manifold based on the prey’s motion in some of …

Evaluation Of The Biodegradability And Toxicity Of Pca And Mpca, Juan Rueda

Electronic Theses and Dissertations

The main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and then they are transported on public roads for incineration as hazardous materials. A new method using alpha ketoglutaric acid (AKGA) was proposed …

Virtual Interactions With Real-Agents For Sustainable Natural Resource Management, Tyler Pierce

Electronic Theses and Dissertations

Common pool resource management systems are complex to manage due to the absence of a clear understanding of the effects of users’ behavioral characteristics. Non-cooperative decision making based on individual rationality (as opposed to group rationality) and a tendency to free ride due to lack of trust and information about other users’ behavior creates externalities and can lead to tragedy of the commons without intervention by a regulator. Nevertheless, even regulatory institutions often fail to sustain natural common pool resources in the absence of clear understanding of the responses of multiple heterogeneous decision makers to different regulation schemes. While modeling …

Near-Road Dispersion Modeling Of Mobile Source Air Toxics (Msats) In Florida, Kurt Westerlund

Electronic Theses and Dissertations

There is a growing public concern that emissions of mobile source air toxics (MSATs) from motor vehicles may pose a threat to human health. At present, no state or federal agencies require dispersion modeling of these compounds, but many agencies are concerned about potential future requirements. Current air pollution professionals are familiar with Federal Highway Administration (FHWA) and U.S. Environmental Protection Agency (EPA) requirements for dispersion modeling to produce predicted concentrations for comparison with appropriate standards. This research examined a method in which the potential near-road concentrations of MSATs were calculated. It was believed that by assessing MSATs in much …

Automatically Acquiring A Semantic Network Of Related Concepts, Sean Szumlanski

Electronic Theses and Dissertations

We describe the automatic acquisition of a semantic network in which over 7,500 of the most frequently occurring nouns in the English language are linked to their semantically related concepts in the WordNet noun ontology. Relatedness between nouns is discovered automatically from lexical co-occurrence in Wikipedia texts using a novel adaptation of an information theoretic inspired measure. Our algorithm then capitalizes on salient sense clustering among these semantic associates to automatically disambiguate them to their corresponding WordNet noun senses (i.e., concepts). The resultant concept-to-concept associations, stemming from 7,593 target nouns, with 17,104 distinct senses among them, constitute a large-scale semantic …

Recognition Of Complex Events In Open-Source Web-Scale Videos: Features, Intermediate Representations And Their Temporal Interactions, Subhabrata Bhattacharya

Electronic Theses and Dissertations

Recognition of complex events in consumer uploaded Internet videos, captured under realworld settings, has emerged as a challenging area of research across both computer vision and multimedia community. In this dissertation, we present a systematic decomposition of complex events into hierarchical components and make an in-depth analysis of how existing research are being used to cater to various levels of this hierarchy and identify three key stages where we make novel contributions, keeping complex events in focus. These are listed as follows: (a) Extraction of novel semi-global features – firstly, we introduce a Lie-algebra based representation of dominant camera motion …

Nano-Particles In Multi-Scale Composites And Ballistic Applications, Jason Gibson

Electronic Theses and Dissertations

Carbon nanotubes, graphene and nano sized core shell rubber particles have all been extensively researched for their capability to improve mechanical properties of thermoset resins. However, there has been a lack of research on their evaluation for energy absorption in high velocity impact scenarios, and the fundamental mechanics of their failure mechanisms during highly dynamic stress transfer through the matrix. This fundamental research is essential for laying the foundation for improvement in ballistic performance in composite armor. In hard armor applications, energy absorption is largely accomplished through delamination between plies of the composite laminate. This energy absorption is accomplished through …

A Dna Computer For Glioblastoma Multiforme Diagnosis And Drug Delivery, Sumaiya F. Hashmi

CMC Senior Theses

Glioblastoma multiforme (GBM) is a debilitating malignant brain tumor with expected patient survival of less than a year and limited responsiveness to most treatments, often requiring biopsy for diagnosis and invasive surgery for treatment. We propose a DNA computer system, consisting of input, computation, and output components, for diagnosis and treatment. The input component will detect the presence of three GBM biomarkers: vascular endothelial growth factor (VEGF), caveolin-1α (CAV), and B2 receptors. The computation component will include indicator segments for each of these genes, and ensure that output is only released if all the biomarkers are present. The output component …

Engineering Novel Terpene Production Platforms In The Yeast Saccharomyces Cerevisiae, Xun Zhuang

Theses and Dissertations--Plant and Soil Sciences

The chemical diversity and biological activities of terpene and terpenoids have served in the development of new flavors, fragrances, medicines and pesticides. While terpenes are made predominantly by plants and microbes in small amounts and as components of complex mixtures, chemical synthesis of terpenes remains technically challenging, costly and inefficient. In this dissertation, methods to create new yeast lines possessing a dispensable mevalonate biosynthetic pathway wherein carbon flux can be diverted to build any chemical class of terpene product are described. The ability of this line to generate diterpenes was next investigated. Using a 5.5 L fed bath fermentation system, …