Engineering Commons^™

On The Application Of Recursive Nonlinear State Transformations And Nonlinear Feedback To Enable Continuous Thrust Spacecraft Orbital Rendezvous, Parisa Khosravi

USF Tampa Graduate Theses and Dissertations

This dissertation presents a method to address exact feedback linearization problems based on the recursive application of approximate feedback linearization techniques. An approximate feedback linearization method is applied recursively to systems which are known to be an exact feedback linearizable to obtain a family of exact solutions up to the ρ-th degree utilizing the null space that appears as part of the computations. The coordinate transformation and feedback parameters are computed symbolically using a one-step approach in multi-stage form. This algorithm is algebraic and computationally simpler than solving the set of nonlinear partial differential equations. We employ the approximate feedback …

A Barker Type Approach For Measuring And Interpreting Vle Of Polymer Mixed Solvent Systems, Vaishali Jain

USF Tampa Graduate Theses and Dissertations

The environment around us has a great impact on human health. A polluted environment can adversely impact human health and cause diseases like cancer, skin diseases, breathing problems and many more and hence altering the quality of life. Hence it is very important to develop sensors that can efficiently detect these harmful substances from environment. Volatile organic compounds (VOCs) are carbon-based chemical substances that are volatile even at ambient temperature and pressure conditions which enter the atmosphere through industrial processes, building materials, etc.

Acoustic wave devices can detect very low concentrations (ppm, ppb) of organic compounds in the environment. A …

Investigation Of Coo Ato For Solar Cells And Infrared Sheaths, Manopriya Devisetty Subramanyam

USF Tampa Graduate Theses and Dissertations

Solar as an energy source is expected to grow fastest from now to 2050. Increasing the efficiency is usually achieved by increasing the short circuit current density (JSC) and/or the fill factor. Improving the efficiency of solar cells will be an ongoing effort.Structurally solar technologies can be classified into two types, wafer-based and thin-film-based. Wafer solar cells have been used in this study. The anti-reflective layer on top of solar cells has been fabricated by a process called electrospinning to tune the solar cells' top surface with the desired thickness and dimensions of the nanofibers. The nanofibers' dimensions, shape, and …

Sulfate Optimization In The Cement-Slag Blended System Based On Calorimetry And Strength Studies, Mustafa Fincan

USF Tampa Graduate Theses and Dissertations

Optimization of sulfur trioxide (SO³) content is typically conducted for plain cements (OPC-based) paste or mortar systems using compressive strength testing and isothermal calorimetry for quality control. The objective of these procedures is to ensure adequate strength and set properties by controlling the time of occurrence of the aluminate peak by adjusting the SO³ content by incremental addition of sulfate in the form of hemihydrate at three or more levels, at the same time attempting to maximize either strength or heat of hydration at 1 and 3 days. The inclusion of supplementary cementitious materials such as blast …

Insights Into The Role Of Metal Composition, Preparation Method, Catalyst Pretreatment For Application In The Development Of Catalytic Reforming Materials For Intensified Conversion Of Biogas Sourced Methane, Yetunde Oluwatosin Sokefun

USF Tampa Graduate Theses and Dissertations

The combustion of fossil fuel sources, crude oil, natural gas, and coal to meet the world’s energy demand has contributed to the increased emissions of carbon dioxide and other harmful gases to the environment. These negative contributions and their resulting impact on environmental conditions and several reports of their peak production and eventual depletion have influenced the need for cleaner and alternative energy production using renewable energy sources.

From the available renewable energy sources ranging from wind, solar, hydrothermal, geothermal, and biomass, biomass is an attractive option because it is largely ubiquitous and a waste commodity that can be converted …

Analysis Of Denial Of Service Attacks In Emerging Software Defined Network Infrastructures, Andrea P. Wright

USF Tampa Graduate Theses and Dissertations

Software defined networking (SDN) improves upon traditional networking protocol technologies by decoupling the data and control planes and moving all control provisioning decisions to a centralized SDN controller entity. This concept has matured over the last decade, having gained strong industry traction, and is now being widely deployed within enterprise and carrier networks to streamline network services provisioning and reduce costs. Overall, centralized control delivers much more cost-effective and flexible networking setups that can support a wide range of customized user-driven network management applications, e.g., traffic engineering, security, survivability, admission control, policy control, etc.

However, the separation of the data …

An Automated Framework For Connected Speech Evaluation Of Neurodegenerative Disease: A Case Study In Parkinson's Disease, Sai Bharadwaj Appakaya

USF Tampa Graduate Theses and Dissertations

Neurodegenerative diseases affect millions of people around the world. The progressive degeneration worsens the symptoms, heavily impacting the quality of life of the patients as well as the caregivers. Speech production is one of the physiological processes affected by neurodegenerative diseases like Alzheimer’s disease, amyotrophic lateral sclerosis (ALS) and Parkinson’s disease (PD). Speech is the most basic form of communication, and the effect of neurodegeneration degrades speech production, thereby reducing social interaction and mental well-being. PD is the second most common neurodegenerative disease affecting speech production in 90% of the diagnosed individuals. Speech analysis methods for PD in clinical methods …

Impact Of Grain Morphology On The Temporal Evolution Of Interfacial Area During Multi-Phase Flow In Porous Media, Fizza Zahid

USF Tampa Graduate Theses and Dissertations

Many environmental issues deal with the movement of immiscible fluids in the subsurface, e.g., cleanup of oil spills and geological carbon dioxide sequestration. Engineers face a constant challenge to improve the efficiency of these processes. This can be facilitated by studying the underlying physics of how fluids flow and interact in these systems.

Traditionally, lab experiments can provide reliable information about fluid architecture in porous medium, such as trapped fluid volumes and contact area between two immiscible fluids (interfacial area). However, these methods can be expensive and tedious. A well designed numerical experiment is not only able to describe fluid …

Corrosion Rate Prediction In Frp-Concrete Repair, Mohammad A. Khawaja

USF Tampa Graduate Theses and Dissertations

Research has proven that wrapping structural elements with fiber-reinforced polymers (FRPs) slows down chloride-induced corrosion rate but does not stop it. Although FRP has been used for corrosion repair for over 40 years, predictive corrosion rate models for FRP-concrete systems are limited in literature. This dissertation presents an oxygen diffusion-based predictive framework to estimate corrosion rate in FRP-concrete systems.

The dissertation has three main components. First, a core framework that is referred to as Khawaja-Sen-Bhethanabotla (KSB) model. In the KSB model, statistical methods were used to extend experimental data on oxygen permeation coefficients. These data were for one and two …

Power System Optimization Methods: Convex Relaxation And Benders Decomposition, Minyue Ma

USF Tampa Graduate Theses and Dissertations

Power system optimization methods are wildly used to solve power system problems. Engineers adopt different methods to keep the reliability and efficiency of the power system operation, planning and control. This dissertation focuses on the application and implementation of two optimization methods: Convex relaxation and Benders' decomposition.

The first part of the dissertation focuses on the application of convex relaxation to solve Alternating Current Optimal Power Flow (ACOPF) problems. In the completed work, a 3-node cycle based sparse convex relaxation is proposed to solve ACOPF problems. This method adds virtual lines in minimal chordless cycles to decompose each of them …

A Modular Framework For Multi-Rotor Unmanned Aerial Vehicles For Military Operations, Dante Tezza

USF Tampa Graduate Theses and Dissertations

Multi-rotor Unmanned Aerial Vehicles (MR-UAV) are commonly used in a wide range of military operations. However, current MR-UAV models have limited payload capabilities and flight time, making it impractical for a single system to be well-suited for different applications. For instance, a drone designed to carry heavier equipment is not well suited for uses that require agility and speed. Therefore, military organizations employ multiple MR-UAV models, leading to complex logistics, training, and overall increased costs.

This dissertation presents a modular MR-UAV framework that allows a user to quickly tailor the aircraft for different military operations by easily changing modular parts …

Assessment Of The Environmental Sustainability Of A Small Water Production Facility In Madagascar, Jesal Patel

USF Tampa Graduate Theses and Dissertations

Nearly 2.2 billion people around the globe struggle with access to safely managed drinking water (WHO/UNICEF, 2019), however, there have been certain initiatives taken, particularly by means of small water production facilities for enhancing access to basic drinking water services in rural areas. The water production facility, specifically located in the low- and middle-income countries, usually encounter operational difficulties as a result of limited availability of resources and are required to depend on other resourceful countries for goods and services. Although, with limited research done for assessing the environmental sustainability of water facilities in low- and middle-income countries, numerous data …

Techno-Economic Analysis Of Polyethylene Terephthalate Bio-Upcycling, Benard Nyawanga

USF Tampa Graduate Theses and Dissertations

Plastics have been used in almost every household appliance and various industrial applications for more than one hundred years. Plastic is among the most used materials in manufacturing worldwide. Plastic is cheap, light, durable, flexible, non-toxic, etc., and these properties make it suitable to use in manufacturing many types of appliances and materials. There has been an excessive reliance on plastic, leading to mass production. Despite being overly produced, there has been very little effort to recycle plastic, leading to massive accumulation of this environment. Plastic wastes are found in large patches in the world's oceans, waterways, and land. In …

Investigating The Novel Role Of Dextromethorphan In Mitigating Oxidative Stress Induced Changes In Retinal Pigment Epithelial Cells (Rpe), Zeinab A. Mohamed

USF Tampa Graduate Theses and Dissertations

Oxidative stress contributes to the degeneration of retinal pigment epithelial (RPE) cells and photoreceptors that lead to the dry form of age-related macular degeneration. Activation of N-Methyl-D-aspartate (NMDA) receptors contributes to the increase of free radicals that induce oxidative stress-induced changes. Our study investigates if Dextromethorphan, an NMDA receptor antagonist, reverses oxidative stress-induced changes in RPE. We used Paraquat and H2O2 as oxidative stress-inducing agents to induce oxidative damage in human ARPE-19 cells. To illustrate the change in cell viability and measure the apoptosis of ARPE-19 cells from oxidative damage, we performed MTT assay and Annexin V-DAPI flow cytometry analysis. …

Efficient Hardware Constructions For Error Detection Of Post-Quantum Cryptographic Schemes, Alvaro Cintas Canto

USF Tampa Graduate Theses and Dissertations

Quantum computers are presumed to be able to break nearly all public-key encryption algorithms used today. The National Institute of Standards and Technology (NIST) started the process of soliciting and standardizing one or more quantum computer resistant public-key cryptographic algorithms in late 2017. It is estimated that the current and last phase of the standardization process will last till 2022-2024. Among those candidates, code-based and multivariate-based cryptography are a promising solution for thwarting attacks based on quantum computers. Nevertheless, although code-based and multivariate-based cryptography, e.g., McEliece, Niederreiter, and Luov cryptosystems, have good error correction capabilities, research has shown their hardware …

Effect Of Se Composition In Cdse1-XTEx/Cdte Solar Cells, Sheikh Tawsif Elahi

USF Tampa Graduate Theses and Dissertations

Cadmium Telluride solar cell is a leading thin film photovoltaic in the market today. Constant enhancement of efficiency in the last decade has made its position firmer in research interest as well. The record cell efficiency for CdTe solar cells is 22.1%. The theoretical limit suggests that there is still room for efficiency improvements. Reducing the band gap of CdTe solar cells can improve the short circuit current and overall cell performance.

This work focuses on bandgap engineering of the CdTe layer by incorporating Selenium (Se) in to form the compound CdS_exTe_1-x (CST) which can have a …

Understanding The Leaching Mechanism For Lead (Pb) Found In Components Of Locally Manufactured Handpumps In Eastern Madagascar, Nidhi Shah

USF Tampa Graduate Theses and Dissertations

This research sought to determine the lead leaching mechanism impacted by an inorganic scale observed from lead valve weights of the pitcher pump systems used in Tamatave, Madagascar. Based on previous research, these valve weights are considered to be a major source for high lead levels in pump water consumed by the residents. As a part of the study, Raman Spectroscopy, X-ray Fluorescence Spectroscopy (XRF) and Energy Dispersive Spectroscopy with Scanning Electron Microscope (SEM-EDS) were performed to address the objectives of this research. The pump component samples for the analysis were selected based on the amount and visual characteristics of …

Longitudinal Trajectory Tracking Analysis For Autonomous Electric Vehicles Based On Pid Control, Hossein Amiri

USF Tampa Graduate Theses and Dissertations

The implementation of autonomous vehicles has huge potential for revolutionizing transportation as we currently know it. All use cases of autonomous vehicles require the vehicle to travel on a pre-specified path. Accurate tracking of this defined trajectory is a crucial aspect of the implementation of autonomous vehicles; a controller system is required to translate this pre- defined trajectory in the form of the throttle, brake, and steering inputs. This project covers the application of a Proportional-Integral-Derivative (PID) controller to achieve longitudinal trajectory tracking of autonomous electric vehicles with stability and accuracy in the CARLA autonomous driving simulation platform. The implemented …

Passive Nitrifying Biofilters For Onsite Treatment Of Saline Domestic Wastewater, Daniel Arnulfo Delgado

USF Tampa Graduate Theses and Dissertations

The infrastructure to support the growing world population has polluted many water bodies with nitrogen from urban and agricultural runoff and failing wastewater systems, such as improperly sited and maintained septic systems. Septic systems present a low energy and maintenance option to treat domestic wastewater and is a treatment option that can be done far from a centralized grid. This further reduces cost, maintenance, and energy as it reduces the need to build and maintaining sewage piping and the infrastructure to move the water longer distances. However, these systems tend to fail when their upkeep is left to homeowners that …

Prediction Of The Effects Of Turbulence On Vehicle Hydroplaning Using A Numerical Model, Thathsarani Dilini Herath Herath Mudiyanselage

USF Tampa Graduate Theses and Dissertations

Pneumatic hydroplaning has been identified as one of the major causes of wet weathertraffic accidents. Therefore, knowledge of potential hydroplaning speeds is crucial in designing roadways to reduce crash risks. It has been shown that the tire inflation pressure is the predominant factor affecting the hydroplaning speed while factors such as the water film thickness also contribute heavily to this phenomenon. Extensive research has been directed at the development of accurate models to predict the effects of vehicle characteristics, pavement conditions and water film thickness on hydroplaning. Current literature does not indicate any studies directed at understanding the effects of …

Formulation And Characterization Of Raloxifene Nanostructured Lipid Carries For Permeability Enhancement Applications, Anju Sharma

USF Tampa Graduate Theses and Dissertations

Raloxifene (RLX), a BCS class-II drug is a selective estrogen receptor modulator (SERM)having estrogenic effect on bone and antiestrogenic effect on endometrium and breast respectively. Low solubility, high permeability, high metabolism and low bioavailability are the characteristics of raloxifene. It is used to prevent and treat in women and those on It is also used to reduce the risk of in those at high risk. Although 60% is absorbed orally, raloxifene shows extremely poor bioavailability (2%) owing to its low solubility and an extensive (>90%) intestinal/hepatic first-pass metabolism. Hence it becomes important to increase the solubility of raloxifene in …

Thermal Management Of Lithium-Ion Batteries Using Supercapacitors, Sanskruta Dhotre

USF Tampa Graduate Theses and Dissertations

As the market for renewable resources increases, the bandwidth of applications using Li-ion batteries as the primary source of energy also increases. Li-ion batteries are at a risk of undergoing thermal runaway under uncontrolled situations. Overcharging, over-discharging, high internal temperatures, etc. are all factors towards the gradual degradation of Li-ion battery performance. Therefore, it is important to have an efficient battery management system to ensure the smooth functioning of the battery.

Thermal management systems is an important aspect of the battery management system to keep battery temperatures under critical levels. Although, there are various methods of cooling down the battery …

Strategies In Botnet Detection And Privacy Preserving Machine Learning, Di Zhuang

USF Tampa Graduate Theses and Dissertations

Peer-to-peer (P2P) botnets have become one of the major threats in network security for serving as the infrastructure that responsible for various of cyber-crimes. Though a few existing work claimed to detect traditional botnets effectively, the problem of detecting P2P botnets involves more challenges. In this dissertation, we present two P2P botnet detection systems, PeerHunter and Enhanced PeerHunter. PeerHunter starts from a P2P hosts detection component. Then, it uses mutual contacts as the main feature to cluster bots into communities. Finally, it uses community behavior analysis to detect potential botnet communities and further identify bot candidates. Enhanced PeerHunter is an …

Feasibility Of Epoxy Bond Enhancement On High-Strength Concrete, Amanda A. Lewis

USF Tampa Graduate Theses and Dissertations

While fiber-reinforced polymer materials have many applications in various industries,when used structurally, many cases, such as flexural and shear strengthening, are considered bond critical. Interfacial bond quality between a fiber-reinforced polymer system and the substrate is dependent on two mechanisms: chemical bonding and mechanical interlock, with mechanical interlock having the greater effect on bond quality. Mechanical interlock describes the type of bond that occurs as a result of surface roughness and substrate porosity and can be significantly affected by surface preparation methods and surface moisture. This study aims to explore the possibility of enhancing bond quality between carbon-fiberreinforced polymers and …

Fabrication And Characterization Methods Of Self-Cleaning Coatings For Solar Panels Application, Mohammed Khaleel M Alhussain

USF Tampa Graduate Theses and Dissertations

Transparent self-cleaning coatings with superhydrophobic and superhydrophilic behavior are of great interest in a wide range of industrial applications such as automotive, solar panels, windows, and optical devices. Each has its uses, properties, and characteristics. For the use of these coatings on solar panels, certain features are important in maintaining the efficiency of the panels in different weather conditions and reducing the operation and maintenance cost, such as self-cleaning, high transparency, antifouling, anti-fogging, and anti-icing. Herein, we have investigated the fabrication of self-cleaning coatings using two simple methods and ways to improve their characteristics. In the first method, a hydrophobic …

A Systems Approach For Improving The Performance Of Rural Community-Managed Water Systems Using Siasar: Case Studies In Bolivia And Colombia, Rachel A. Cannon

USF Tampa Graduate Theses and Dissertations

Globally, the focus of environmental engineers and water, sanitation, and hygiene (WASH) professionals in the rural water sector has shifted from building new technology to ensuring long-term functionality of water systems and closing the access gap between urban and rural residents. In Latin America and the Caribbean, the main challenges to ensuring clean water for all rural residents is poor service delivery quality and limited sustainability over time. A common management strategy in the region, and globally, is community-management, where community members manage, operate, and maintain the water system through cost sharing and financial management. The failure of community-managed water …

Heterogeneous Performance Modeling With Applications In Healthcare And Reliability Engineering, Xuxue Sun

USF Tampa Graduate Theses and Dissertations

In both health systems engineering and reliability engineering, individual units, such as patients and product units, often exhibit highly heterogeneous performance due to the influences of various observed individual characteristics and unobserved/unknown factors. Successful modeling of the heterogeneous performance of individual units is of great importance. It will not only facilitate the identification and quantification of influencing factors for improving performance of individual units, but also improve prediction accuracy of their future performance. This will further facilitate better decisions, such as cost-effective and adaptive healthcare resource planning decision, and proactive maintenance policy at reduced cost. However, due to the highly …

The Effect Of Cement And Blast Furnace Slag Characteristics On Expansion Of Heat-Cured Mortar Specimens, Jair G. Burgos

USF Tampa Graduate Theses and Dissertations

Delayed ettringite formation (DEF) is a durability issue that typically occurs in concrete exposed to high temperatures at an early age such as precast elements and massive concrete structural elements. There are many advantages to precast concrete such as its quality control, better safety control, and reusable forms, which make them cheaper than casting on site [1]. Heat curing of precast concrete is conducted to obtain high early-strength. However, in doing so, durability issues can arise in the form of internal sulfate attack also known as DEF, if the internal temperature of concrete exceeds 70°C. Past this threshold, ettringite decomposes …

Plasmonic Photocatalysis For Gas-Phase Degradation Of Total Volatile Organic Compounds: Theory, Experimentation, And Catalyst Stability, Amaury P. Betancourt Iii

USF Tampa Graduate Theses and Dissertations

Plasmonic nanomaterials have become a strong contender for improving the efficiency of photocatalytic degradation of air pollutants. This study demonstrates an easy and scalable fabrication method, employing electron beam evaporation and rapid thermal annealing, for producing plasmonic photocatalysts. Samples were made by either coating silver on, or layering silica-protected (i.e., silica-coated) or unprotected (i.e., uncoated) silver beneath, the photocatalyst (either zinc oxide or titanium dioxide). Stability and catalytic performance for gas-phase toluene degradation was assessed by monitoring total volatile organic compound (TVOC) concentration versus ultraviolet-A (UV-A) illumination time in a recirculating batch reactor (plate-type flow-through). Samples were characterized using a …

Evaluating The Performance Of Devices Engineering To Quantify The Fars Test, Harsh Patel

USF Tampa Graduate Theses and Dissertations

Clinical rating scales play a major role in assessing progressive neurological diseases. Neurologists use these rating scales to provide a better diagnosis, to provide a better treatment plan, and to analyze the outcome of clinical trials. Friedreich’s ataxia (FA) is a neurodegenerative disease that causes ataxia in limbs, speech impairment, and polyneuropathy. Since FA is a progressive disease, various rating scales have been standardized to provide an objective assessment of the patient’s current condition. The Friedreich Ataxia Rating Scale (FARS) includes several tests to capture neurological features of FA and to assess the functional stage of ataxia. The rubrics used …