Engineering Commons^™

Non-Precious Metal Catalysts For Oxygen Reduction Reaction In Alkaline Solutions, Zhewen Yin

USF Tampa Graduate Theses and Dissertations

Mesoporous WO3 powders were prepared via sol-gel processing synthesis using nonionic surfactant Pluronic (P-123) as the template. The influences of heating temperature on the pore structure and properties of WO3 powders were investigated. Three kinds of modifications were compared and evaluated after finding out the best heating condition. Different amount of lanthanum was doped into mesoporous WO3 to improve its Oxygen Reduction Reaction (ORR) activity. Several factors contributing to the increase of catalytic performance were discussed. Vulcan carbon powder was also used as a support to increase the catalysts’ electrical conductivity as well as dispersity. The component, microstructure and specific …

Modeling Corrosion Damage And Repair To A 3, Joseph R. Scott

USF Tampa Graduate Theses and Dissertations

The main purpose of this study was to investigate and implement a repair design for corrosion damaged bridge bents in order to resist lateral loading, such as wind loads or ship impact. Using the results from a one-third scale bridge bent constructed and tested for a previous study, non-linear modeling was used to simulate the same corrosion damage and load response. The principle variable considered was damage, represented as a percent of effective area loss of prestressing steel within a designated damage zone along the length of piles. Other influencing variables included: prestress transfer length, localized loss in prestress due …

Visualizing Load Path In Perforated Shear Walls, Ying Chih Chen

USF Tampa Graduate Theses and Dissertations

Shear walls are the primary lateral load resisting elements in bearing wall systems used in masonry construction. Horizontal loads due to wind or earthquake are transferred to vertical walls by diaphragms that are rigid such as concrete floor slabs or flexible such as wood floors. With rigid diaphragms, loads are apportioned to the supporting walls based on their relative rigidity. Walls with openings accommodating doors and windows (“perforated walls”) have reduced rigidity that can be determined using available hand calculation methods. These methods primarily focus on analysis procedures, not on the visualization of the load path that is critically important …

Comparison Of Functional Porous Organic Polymers (Pops) And Natural Material Zeolite For Nitrogen Removal And Recovery From Synthetic Urine, Yan Zhang

USF Tampa Graduate Theses and Dissertations

Urine comprises around 1% of domestic sewage volume but holds 80% of total nitrogen. Source separation is a sustainable way to wastewater management than traditional way due to low energy cost and preventing certain pollutants into wastewater treatment plants. Currently, removing and recovering nitrogen from source-separated urine has attracted more and more interests. Of them, ion exchange was used for removal and recovery of nitrogen in the form of ammonia from synthetic urine for potential application as a fertilizer in agriculture. No previous research studies were conducted to investigate the removal and recovery of nitrogen from hydrolyzed urine by ion …

Conversion Of Biomass To Liquid Hydrocarbon Fuels Via Anaerobic Digestion: A Feasibility Study, Ahmad Naqi

USF Tampa Graduate Theses and Dissertations

The use of biomass as a potential feedstock for the production of liquid hydrocarbon fuels has been under investigation in the last few decades. This paper discusses a preliminary design and a feasibility study of producing liquid hydrocarbon fuels from biomass through a combined biochemical and thermochemical route. The process involves anaerobic digestion (AD) of the biodegradable portion of the biomass to produce methane rich gas. The methane rich biogas stream is purified by removing contaminants and upgraded to liquid hydrocarbon fuel in a gas to liquid facility (GTL) via thermochemical conversion route. The biogas conversion involves two major steps: …

Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio

USF Tampa Graduate Theses and Dissertations

In future human spaceflight missions, with prolonged exposure to microgravity, resistive and aerobic exercises will be countermeasures for bone loss, muscle loss, and decreased aerobic capacity. Two of the exercises of interest are squats and rowing. The cyclic forces produced during these exercises are at relatively low frequencies which are likely to excite structural resonances of space vehicles. Vibration Isolation Systems (VIS) are being designed to be paired with future exploration exercise devices in order to prevent these cyclic exercise forces from impacting the space vehicle. The VIS may be configured such that a platform supports the human and exercise …

Combining Thermo-Plasmonics With Microfluidics For Biological Applications, Sharad Ambardar

USF Tampa Graduate Theses and Dissertations

In this project we, for the first time, integrated microfluidics with thermo-plasmonics. While microfluidics is a popular platform allowing experiments with small volumes of fluid, thermo-plasmonics can be used for powerful particle manipulation including capturing, mixing, filtering and projection. Combined, these two techniques give us an opportunity to work with numerous complex fluids containing particles, cells, and micro-beads. Here we designed, developed and tested several devices demonstrating various aspects of this exciting hybrid technology. This required use of soft lithography, metal deposition, 3D printing, oxygen plasma treatment and several other surface modification techniques. Additional challenges were in the fabrication of …

Supported Perovskite-Type Oxides: Establishing A Foundation For Co2 Conversion Through Reverse Water-Gas Shift Chemical Looping, Bryan J. Hare

USF Tampa Graduate Theses and Dissertations

Perovskite-type oxides show irrefutable potential for feasible thermochemical solar-driven CO₂ conversion. These materials exhibit the exact characteristics required by the low temperature reverse water-gas shift chemical looping process. These properties include structural endurance and high oxygen redox capacity, which results in the formation of numerous oxygen vacancies, or active sites for CO₂ conversion. A major drawback is the decrease in oxygen self-diffusion with increasing perovskite particle size. In this study, the La_0.75Sr_0.25FeO₃ (LSF) perovskite oxide was combined with various supports including popular redox materials CeO₂ and ZrO₂ along with more abundant …

Design And Implementation Of A Ferrocement Improved Cookstove In Rural Panama, Josh Donegan

USF Tampa Graduate Theses and Dissertations

Household air pollution contributes to the premature death of more than 4 million people annually. Improved cookstoves are one technological intervention that can potentially reduce exposure to household air pollution. However, improved cookstove implementation programs need to consider measures to increase sustainability and promote long-term adoption. The objectives of this research were 1) to develop and implement a new ferrocement cookstove for Peña Blanca, a rural indigenous community in the Ngäbe-Bugle region of Panama, 2) to evaluate its potential sustainability in comparison to the most common cooking technologies observed in the community, 3) to prepare a construction manual for the …

Design Of Micro-Scale Energy Harvesting Systems For Low Power Applications Using Enhanced Power Management System, Majdi M. Ababneh

USF Tampa Graduate Theses and Dissertations

The great innovations of the last century have ushered continuous progress in many areas of technology, especially in the form of miniaturization of electronic circuits. This progress shows a trend towards consistent decreases in power requirements due to miniaturization. According to the ITRS and industry leaders, such as Intel, the challenge of managing and providing power efficiency still persist as scaling down of devices continues. A variety of power sources can be used in order to provide power to low power applications. Few of these sources have favorable characteristics and can be designed to deliver maximum power such as the …

Effectiveness Of Biocide Substitution And Management Plan Implementation For The Control Of, Adelmarie Bones

USF Tampa Graduate Theses and Dissertations

After the notorious outbreak and discovery of Legionella bacteria in 1976, the waterborne pathogen was added to the list of disease-causing agents associated with the built environment. Legionella pneumophila was discovered when it was identified as the agent that caused 34 deaths and an outbreak of pneumonia-like symptoms in several attendees of the 1976 American Legion Convention held in Philadelphia (OSHA, 2017).

Recently published data from the year 2015 reported more than 6,000 Legionnaires’ cases identified in the United States (CDC, 2016). This is a concerning number given that one in every ten infected persons will die of the disease. …

Assessing The Impacts Of Climate Change On Streamflow And Reservoir Operation In Central Florida, Toni Panaou

USF Tampa Graduate Theses and Dissertations

Climate change is a global concern as it may affect many aspects of life, including water supply. A tool used to model climate change’s impacts is called a General Circulation Model (GCM). GCMs project future scenarios including temperature and precipitation, but these are designed at a coarse resolution and require downscaling for employment for regional hydrologic modeling. There is a vast amount of research on downscaling and bias-correcting GCMs data, but it is unknown whether these techniques alter precipitation signals embedded in these models or reproduce climate states that are viable for water resource planning and management. Using the Tampa, …

A High Accuracy Microwave Radiometric Thermometer To Measure Internal Body Temperature, Michael D. Grady

USF Tampa Graduate Theses and Dissertations

The Center for Disease Control and Prevention (CDC) released heat illness data which highlighted that ~29 heat stress hospitalizations and ~3 heat-related deaths occurred every day during the summer months within the US from years 2000 to 2014. Heatstroke- the most severe form of heat illness which oftentimes lead to death- has been cited to be entirely preventable if a timely intervention is introduced. This dissertation uses microwave radiometric thermometry to perform wireless non-invasive internal body temperature monitoring which can enable intervention methods that help to prevent deaths associated with heat-illness.

Overall, this dissertation develops a comprehensive closed-form analytical radiometric …

Graph-Based Latent Embedding, Annotation And Representation Learning In Neural Networks For Semi-Supervised And Unsupervised Settings, Ismail Ozsel Kilinc

USF Tampa Graduate Theses and Dissertations

Machine learning has been immensely successful in supervised learning with outstanding examples in major industrial applications such as voice and image recognition. Following these developments, the most recent research has now begun to focus primarily on algorithms which can exploit very large sets of unlabeled examples to reduce the amount of manually labeled data required for existing models to perform well. In this dissertation, we propose graph-based latent embedding/annotation/representation learning techniques in neural networks tailored for semi-supervised and unsupervised learning problems. Specifically, we propose a novel regularization technique called Graph-based Activity Regularization (GAR) and a novel output layer modification called …

Construction Effects On The Side Shear Of Drilled Shafts, Lucas Caliari De Lima

USF Tampa Graduate Theses and Dissertations

Design methods for side shear of drilled shafts, including the resistance factors that should be applied, do not account for any specific construction procedure. Instead, design often relies on analysis of case studies which include all construction methods used in each geomaterial type (e.g. clays, sands and rocks), or on parametric analysis. Nonetheless, literature suggests that different construction procedures result in varying side shear.

This research investigated 2 types of construction: (1) slurry stabilization in sandy soils using bentonite and polymer products that are commonly used on the field, with exposure times from near 0h to 96h, and (2) temporary …

Direct Digital Manufacturing Of Multi-Layer Wideband Ku-Band Patch Antennas, Merve Kacar

USF Tampa Graduate Theses and Dissertations

Design and performance of fully-printed Ku-band aperture coupled patch antennas fabricated by a direct digital manufacturing (DDM) approach that integrates fused deposition modeling (FDM) of acrylonitrile butadiene styrene (ABS) thermoplastic with in-situ micro-dispensing of conductive silver paste (CB028) are reported. Microstrip line characterizations are performed and demonstrate that misalignment of ABS substrate deposition direction with microstrip line micro-dispensing direction can degrade the effective conductivity up to 60% within the Ku-band, and must be taken into consideration in antenna array feed network designs. Specically, over 125 µm thick ABS substrate, RF loss of 0.052 dB/mm is obtained at 18 GHz, demonstrating …

Design And Simulation Of A Miniature Cylindrical Mirror Auger Electron Energy Analyzer With Secondary Electron Noise Suppression, Jay A. Bieber

USF Tampa Graduate Theses and Dissertations

In the nanoscale metrology industry, there is a need for low-cost instruments, which have the ability to probe the structrure and elemental composition of thin films. This dissertation, describes the research performed to design and simulate a miniature Cylindrical Mirror Analyzer, (CMA), and Auger Electron Spectrometer, (AES). The CMA includes an integrated coaxial thermionic electron source. Electron optics simulations were performed using the Finite Element Method, (FEM), software COMSOL. To address the large Secondary Electron, (SE), noise, inherent in AES spectra, this research also included experiments to create structures in materials, which were intended to suppress SE backgound noise in …

Understanding The Linkages Between Urban Transportation Design And Population Exposure To Traffic-Related Air Pollution: Application Of An Integrated Transportation And Air Pollution Modeling Framework To Tampa, Fl, Sashikanth Gurram

USF Tampa Graduate Theses and Dissertations

Rapid and unplanned urbanization has ushered in a variety of public health challenges, including exposure to traffic pollution and greater dependence on automobiles. Moreover, vulnerable population groups often bear the brunt of negative outcomes and are subject to disproportionate exposure and health effects. This makes it imperative for urban transportation engineers, land use planners, and public health professionals to work synergistically to understand both the relationship between urban design and population exposure to traffic pollution, and its social distribution. Researchers have started to pay close attention to this connection, mainly by conducting observational studies on the relationship between transportation, urban …

18f-Fdg Pet/Ctct-Based Radiomics For The Prediction Of Radiochemotherapy Treatment Outcomes Of Cervical Cancer, Badereldeen Abdulmajeed Altazi

USF Tampa Graduate Theses and Dissertations

Cervical cancer remains the third most commonly diagnosed gynecological malignancy in the United States and throughout the world despite being potentially preventable. Patients diagnosed with cervical cancer may develop local recurrence in the cervix and surrounding structures (vaginal apex, parametrial, or paracervical), regional recurrence in pelvic lymph nodes, distant metastasis, or a combination of all. The management of such treatment outcomes has not been subject to rigorous investigation. Therefore, there is a need for studies and clinical trials that focus on decision making to support the choice of the best treatment modality that leads to the minimal number of adverse …

Dns And Les Of Scalar Transfer Across An Air-Water Interface During Inception And Growth Of Langmuir Circulation, Amine Hafsi

USF Tampa Graduate Theses and Dissertations

Direct numerical simulations (DNS) of an initially quiescent coupled air-water interface driven by an air flow with free stream speed of 5 m/s have been conducted. The DNS solves a scalar advection-diffusion equation for dissolved gas (or scalar) concentration in order to determine the impact of the water-side turbulence on scalar (mass) transfer from the air side to the water side and subsequent vertical transport in the water column. Two simulations are compared: one with a freely deforming interface and a second one with a flat interface. In the first simulation, the deforming interface evolves in the form of gravity-capillary …

Compact And Wideband Mmic Phase Shifters Using Tunable Active Inductor Loaded All-Pass Networks, David M. Zaiden

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the design of monolithically integrated phase shifters at S- and L- frequency bands using a commercially available GaAs process from Triquint. The focus of the design is to operate over a wide bandwidth with full 360° phase shift capability, 50 Ω input/output impedance match and low RMS phase and gain errors. The first version of the design is based on passive all-pass phase shifters integrated with wideband amplifiers to compensate for insertion loss. This design uses a 4-bit system to achieve the required phase shift and each bit consists of 3 sections of all-pass filters designed at …

Physical Layer Algorithms For Reliability And Spectral Efficiency In Wireless Communications, Zekeriyya Esat Ankarali

USF Tampa Graduate Theses and Dissertations

Support of many different services, approximately 1000x increase of current data rates, ultra-reliability, low latency and energy/cost efficiency are among the demands from upcoming 5G standard. In order to meet them, researchers investigate various potential technologies involving different network layers and discuss their trade-offs for possible 5G scenarios. Waveform design is a critical part of these efforts and various alternatives have been heavily discussed over the last few years. Besides that, wireless technology is expected to be deployed in many critical applications including the ones involving with daily life activities, health-care and vehicular traffic. Therefore, security of wireless systems is …

Manipulating Electromagnetic Waves With Enhanced Functionalities Using Nonlinear And Chiral Metamaterials, Sinhara Rishi Malinda Silva

USF Tampa Graduate Theses and Dissertations

Metamaterials are artificial structures, which periodically arranged to exhibit fascinating electromagnetic properties, not existing in nature. A great deal of research in the field of metamaterial was conducted in a linear regime, where the electromagnetic responses are independent of the external electric or magnetic fields. Unfortunately, in linear regime the desired properties of metamaterials have only been achieved within a narrow bandwidth, around a fixed frequency. Therefore, nonlinearity is introduced into metamaterials by merging meta-atoms with well-known nonlinear materials. Nonlinear metamaterials are exploited in this dissertation to introduce and develop applications in microwave frequency with broadband responses. The nonlinearity was …

Design And Modeling Of A High-Power Periodic Spiral Antenna With An Integrated Rejection Band Filter, Jonathan M. O'Brien

USF Tampa Graduate Theses and Dissertations

This work details the design and fabrication of an ultra-wideband periodic spiral antenna (PSA) with a notch filter embedded directly into the radiating aperture. Prototype fabrication of the PSA reveals long assembly time due to forming the antenna element, therefore modifications are made to allow fabricating the antenna elements on a thin, flexible, Polyimide substrate. A transmission line model is develop to support the updated configuration of the antenna elements. In addition, a symmetric spurline filter is integrated into the arms of the spiral antenna in order to address the common problem of interference in ultra-wideband systems. For the first …

Growth, Characterization, And Function Of Ferroelectric, Ferromagnetic Thin Films And Their Heterostructures, Mahesh Hordagoda

USF Tampa Graduate Theses and Dissertations

With recent trends in miniaturization in the electronics sector, ferroelectrics have gained popularity due to their applications in non-volatile RAM. Taking one step further researchers are now exploring multiferroic devices that overcome the drawbacks of ferroelectric (FE) and ferromagnetic (FM) RAM’s while retaining the advantages of both. The work presented in this dissertation focuses on the growth of FE and FM thin film structures. The primary goals of this work include, (1) optimization of the parameters in the pulsed laser deposition (PLD) of FE and FM films and their heterostructures, (2) development of a structure-property relation that leads to enhancements …

Experimental Study Of High-Temperature Range Latent Heat Thermal Energy Storage, Chatura Wickramaratne

USF Tampa Graduate Theses and Dissertations

Among all thermal energy storage (TES) systems, latent heat thermal energy storage (LHTES) attracts high interest due to its high energy density and high exergetic efficiency. Due to the high enthalpy of fusion and low cost, inorganic salts are becoming popular as phase change materials and are used as the storage media in LHTES systems. The main drawbacks for the inorganic salts are their low thermal conductivity and high reactivity above 500°C. Therefore, designing a cost-effective containment at these conditions with longevity is a challenge. Macro-encapsulation of the PCM is one way to solve both the PCM containment issue as …

Development Mems Acoustic Emission Sensors, Adrian Enrique Avila Gomez

USF Tampa Graduate Theses and Dissertations

The purpose of this research is to develop MEMS based acoustic emission sensors for structural health monitoring. Acoustic emission (AE) is a well-established nondestructive testing technique that is typically used to monitor for fatigue cracks in structures, leaks in pressurized systems, damages in composite materials or impacts. This technology can offer a precise evaluation of structural conditions and allow identification of imminent failures or minor failures that can be addressed by planned maintenances routines. AE causes a burst of ultrasonic energy that is measured as high frequency surface vibrations (30 kHz to 1 MHz) generated by transient elastic waves that …

Rf Sensing System For Continuous Blood Glucose Monitoring, Fabiola Araujo Cespedes

USF Tampa Graduate Theses and Dissertations

The purpose of this research was to design a blood glucose sensing system based on the induced shift in the resonant frequency of an antenna patch operating in the ISM band (5.725 – 5.875 GHz). The underlying concept is the fact that when a person has variations in their blood glucose levels, the permittivity of their blood varies accordingly. This research analyzed the feasibility of using an antenna patch as a blood glucose sensing device in three configurations: 1) as an implantable active sensor, 2) as an implantable passive antenna sensor, and 3) as a non-invasive sensor. In the first …

Improving Service Level Of Free-Floating Bike Sharing Systems, Aritra Pal

USF Tampa Graduate Theses and Dissertations

Bike Sharing is a sustainable mode of urban mobility, not only for regular commuters but also for casual users and tourists. Free-floating bike sharing (FFBS) is an innovative bike sharing model, which saves on start-up cost, prevents bike theft, and offers significant opportunities for smart management by tracking bikes in real-time with built-in GPS. Efficient management of a FFBS requires: 1) analyzing its mobility patterns and spatio-temporal imbalance of supply and demand of bikes, 2) developing strategies to mitigate such imbalances, and 3) understanding the causes of a bike getting damaged and developing strategies to minimize them. All of these …

The Relationship Between Total Neuropathy Score-Reduced, Neuropathy Symptoms And Function., Ashraf Abulhaija

USF Tampa Graduate Theses and Dissertations

Chemotherapy Induced Peripheral Neuropathy (CIPN) is a common problem among cancer patients who receive a wide range of chemotherapy. This problem causes a decline in quality of life and increased disabilities. CIPN assessment instruments are either subjective, objective, or a combination of both. So far, there is no agreement on the best way for assessment. The goal of this study was to explore the relationships among subjective and objective CIPN assessment instruments. Specifically, this study aimed to 1) evaluate the relationship between the Total Neuropathy Score-reduced (mainly objective) and patients’ function, as measured by the interference scale of the Chemotherapy-Induced …