Digital Commons Network^™

Design Of Variable Wall Thickness Geometry And Performance Mapping Of Scroll Expanders For Distributed Power Generation, Arun Kumar Narasimhan

USF Tampa Graduate Theses and Dissertations

Low-temperature heat sources such as industrial waste heat, solar, and geothermal are more suitable for small-scale power generation rather than utility scale. In order to maximize the electricity generated from low-temperature heat sources, an efficient expansion device for small-scale power output is necessary. This research work has focused on evaluating the use of a scroll expander and improving its geometrical design for the power output range of 1-25 kW_e.

The first part of the work focusses on modeling the performance of a scroll expander using two non-dimensionless parameters, namely, specific speed and specific diameter. Performance of a scroll …

Effects Of Support Fluid Type On Concrete Integrity And Durability In Drilled Shafts, Sarah J. Mobley

USF Tampa Graduate Theses and Dissertations

Until recently, concrete flow in tremie-placed drilled shafts has been mischaracterized as rising uniformly with laitance formation occurring only at the top of the rising concrete in the shaft. In actuality, concrete first fills a portion of the reinforcement cage to a sufficient height to promote radial flow into the cover region. Depending on support fluid type, the radial flow can produce laitance-filled creases/channels projecting the reinforcing cage configuration to the side of shaft surface. The flow pattern (and creases) can affect filter cake thickness, cover quality and propensity for corrosion. This research examines 52 tremie-placed laboratory drilled shaft specimens …

Study Of Transition Metal Dichalcogenides Via Linear And Non-Linear Spectroscopy, Christopher E. Stevens

USF Tampa Graduate Theses and Dissertations

Beginning with the discovery of graphene, two-dimensional materials have amassed a strong interest. Like graphene, transition metal dichalcogenides (TMDs) can be coaxed into atomically thin sheets which have some impressive properties. Unlike graphene, TMDs also has a change in their electronic band structure causing an indirect band gap to a direct gap transition in its monolayer form. Additionally, these materials lose their inversion symmetry as a monolayer. These unique properties make TMDs a strong candidate for being used in optoelectronic and valleytronic devices. In order for these devices to be successful, the optical properties of TMDs must be thoroughly understood. …

Mhealth Elisa System For Point-Of-Care, Arsenii Zhdanov

USF Tampa Graduate Theses and Dissertations

Enzyme-linked immunosorbent assay (ELISA) is one of the most important technologies for biochemical analysis critical for diagnosis and monitoring of many diseases. Traditional systems for ELISA incubation and reading are expensive and bulky, thus cannot be used at pointof- care or in the field. Here, we design and demonstrate a new miniature mobile phone based system for ELISA. This mHealth system can be used to complete all steps of the assay, including incubation and reading. It can be fabricated at low cost, portable, and can transfer test results via mobile phone. We have designed the sample dispensing system, incubation chamber, …

A Decision-Making Framework For Hybrid Resource Recovery Oriented Wastewater Systems, Nader Rezaei

USF Tampa Graduate Theses and Dissertations

Water shortage, water contamination, and the emerging challenges in sustainable water resources management (e.g., the likely impacts of climate change and population growth) necessitate adopting a reverse logistics approach, which is the process of moving wastewater from its typical final destination back to the water supply chain for reuse purposes. This practice not only reduces the negative impacts of wastewater on the environment, but also provides an alternative to withdrawal from natural water resources, forming a closed-loop water supply chain. However, the design of such a supply chain requires an appropriate sustainability assessment, which simultaneously accounts for economic, environmental, and …

Rf Power Circuit Designs For Wi-Fi Applications, Krishna Manasa Gollapudi

USF Tampa Graduate Theses and Dissertations

In the field of RF/Microwave Engineering, the Wilkinson Power divider is a passive device frequently used for splitting or combining signals. The power fed to the input port is equally or unequally split between N output ports and delivers better performance by achieving isolation between the output ports while matching all the ports. The design comprises simple transmission lines and provides power divider characteristics with the help of quarter wavelength transmission lines with different topologies.

This thesis describes the design and fabrication of lumped and N way power splitter working at an operating frequency of 2.4 GHz. These circuits are …

The Design Of Passive Networks With Full-Wave Component Models, Eric Valentino

USF Tampa Graduate Theses and Dissertations

In this thesis, the design of passive networks with the aid of full-wave simulation software and geometry-based models of lumped elements is investigated. This is done by examining the results of a number of simulation examples, as well as measured data from manufactured designs to compare against simulated equivalents. One such example is a chip antenna evaluation board design, in which the PCB, antenna, matching components and connector are all modeled. When measured, the simulation agreed with the board’s best matched frequency of 5.5 GHz to within 20 MHz. In another, a new antenna layout is generated from an existing …

To Compare Cyclosporine A Nanoformulations For Their Effectiveness In Reducing Nephrotoxicity, Ilkin Nasirli

USF Tampa Graduate Theses and Dissertations

Cyclosporine (CsA) is one of the main immune-suppressant agents which has been used widely in organ transplantation against graft rejection. However, the low oral bioavailability and the associated adverse effects such as nephrotoxicity are the main drawbacks of current usage of this drug. Thus, purpose of this research is to formulate PLGA nanoparticles of CsA to improve its effectiveness and to reduce the nephrotoxicity induced by the plain drug. CsA-loaded PLGA nanoparticles were prepared by the nanoprecipitation method. Particle size and zeta potential of the formulation was determined and percent drug entrapment were also determined. Quantitative estimation was carried out …

Responsive Coatings And Functional Systems From Pectin Polysaccharides, Zeinab Veisi

USF Tampa Graduate Theses and Dissertations

Pectin polysaccharides provide promising potential as all-natural, non-toxic “green” coatings. Pectin polysaccharides have been drawing growing attention as elements of stimuli-responsive systems and as source materials for functionalized robust coatings. They can be extracted from several natural sources and are intrinsically biocompatible. The majority of the applications of pectin gels require a better understanding of the properties of thin layers of gels at surfaces and interfaces. Despite the prevalence of bulk gels of pectin, coatings of pectin have not been reported. In bulk hydrogels, swelling of polymer networks is controlled by a diffusion limited transport process in which the rate …

Carbon Dioxide Adsorption Using Solid Amine Sorbents, Umadevi Gopalakrishnan

USF Tampa Graduate Theses and Dissertations

Biogas, being rich in methane, can be used as a fuel for various end uses such as electricity generation, compressed natural gas (CNG), production of liquid fuels, industrial heating, etc. CO₂ is the major contaminant in biogas (30–50%) along with other impurities such as NH₃, H₂S, and water. CO₂ in the biogas decreases the heating value of biogas. Natural gas pipelines and vehicle use require high purity (> 95%) CH₄. There are many commercial techniques available for CO₂ removal from biogas such as such water scrubbing (WS), chemical scrubbing (CS) using …

On Distributed Control Of Multiagent Systems Under Adverse Conditions, Emre Yildirim

USF Tampa Graduate Theses and Dissertations

The objective of this thesis is (1) to show the experimental validation of recently proposed distributed adaptive control architecture for a class of heterogeneous uncertain multiagent systems as well as (2) to theoretically propose a proportional integral controller for multiagent systems having limited resources in the presence of a disturbance with stability analyses.

With regard to (1), the distributed adaptive control architecture used in the experiment utilizes a control input having a nominal part and an adaptive augmentation part for each agent to suppress the effect of uncertainties and disturbances effectively. This architecture is capable to provide uniform ultimate boundedness …

Encapsulation Of Organic Thermochromic Materials With Silicon Dioxide, Mingyang Huang

USF Tampa Graduate Theses and Dissertations

Currently, functional materials are attracting considerable attention in the effort to solve some tough challenges the world is faced with. Thermochromic (TC) materials have the potential to make buildings more energy efficient because of their ability to change color (i.e black to white) at specific temperatures. Using this property, TC materials can reflect solar radiation in the summer, to keep a building cool during daytime hours, and absorb solar radiation in the winter to keep the building warm when their color is dark. Very often, to increase their durability, thermochromic materials are encapsulated. In this work, a new process has …

Effect Of Promoter (Mn) On The Performance Of Sba-15 Supported Iron Catalysts For High Temperature Fischer-Tropsch Synthesis, Sreya Mariya Seby

USF Tampa Graduate Theses and Dissertations

Development of an effective High Temperature Fischer-Tropsch Synthesis (HTFTS) catalyst is of interest in process intensification that combines methane reforming with long chain hydrocarbon production. Literature indicates iron catalysts supported on mesoporous silica performed relatively well in high temperature applications. In this work, we investigated the effect of manganese promoter on iron catalysts for FTS at 430 °C as it was known from previous studies that manganese promotion could enhance the CO conversion with higher hydrocarbon yields. Also, the effect of temperature on FTS activity was evaluated by testing the base and promoted Fe/SBA-15 catalysts for temperature ranging from 370 …

Improving Stability By Enhancing Critical Fault Clearing Time, Ammara M. Ghani

USF Tampa Graduate Theses and Dissertations

The Bulk Electric System (BES) in the United States includes transmission lines of 100kV and above, transformers of 100kV and above on Low Voltage (LV) side and generating units that step up to 100 kV and above. The BES is a power network that connects different states and utility companies via tie lines for exchange of Power.

To maintain the integrity of power systems, it is very important to keep the BES intact and for that the regulatory authority, North American Electric Reliability Corporation (NERC), has developed over 100s of reliability standards and is responsible to enforce them.

During the …

Sorption Of Benzene, Tolueneand Ethylbenzeneby Plasticized Pema And Pema/Pmma Sensing Films Using Aquartz Crystal Microbalance (Qcm) At 298.15k, Deekshitha Adapa

USF Tampa Graduate Theses and Dissertations

Detection of volatile organic compounds (VOC’s) in the environment is important for human health and wellness. Long term exposure of certain VOC’s like benzene, toluene, ethylbenzene and xylene (BTEX) has a severe effect on human health. There are techniques such as gas chromatography, photo ionization, and mass spectroscopy that are time consuming, require gas sampling and are ineffective in real time sensing in air. Acoustic wave devices such as surface acoustic wave (SAW) devices can be used for sensing BTEX compounds in both vapor and liquid phase. The quartz crystal microbalance (QCM) is a low-frequency acoustic wave device, which can …

Morphology And Detection Of Corrosion On Stainless Steel Reinforcement In Concrete, Julio J. Saire Yanez

USF Tampa Graduate Theses and Dissertations

Stainless steel (SS) has emerged as an alternative corrosion-resistant reinforcement in concrete instead of the commonly used carbon steel (CS). The biggest advantage of SS is that it takes more time for corrosion to initiate than for CS. An additional benefit from the use of SS in concrete may be derived from the period after the corrosion started until the concrete structure reaches a limit state. This period is called corrosion propagation stage (CPS) and it has been hardly studied in SS reinforced structures. The duration of this period could be related, among other factors, to the morphology of corrosion …

Cubesat Constellation Design For Intersatellite Linking, Michael T. White

USF Tampa Graduate Theses and Dissertations

This thesis investigates the concept of controlling a CubeSat constellation in low-Earth orbit. Low-Earth orbits are considered because the torque used for satellite control is supplied with magnetorquers, and the closer the satellite is to Earth’s magnetic field the more control gain can be supplied. Also, this is the expected orbit altitude of future CubeSat constellations to enable communications.

Controlling a CubeSat relies on attitude determination. This means being able to estimate its attitude relative to a given reference frame. To determine the attitude, we propose to use a star tracker and a Kalman filter. A star tracker scans the …

Quantifying The Friedreich Ataxia Rating Scale And The Functional Performance Measures, Chelsea Rene Davis

USF Tampa Graduate Theses and Dissertations

Friedreich Ataxia (FA) is a debilitating autosomal-recessive neurodegenerative disorder which is characterized by ataxia of all four limbs, difficulty walking, areflexia, and dysarthria. Further complications of FA include diabetes, scoliosis, and hypertrophic cardiomyopathy. Approximately three-quarters of people with FA have onset before the age of 25 and in most instances, affected individuals will require the use of a wheelchair within ten years after symptoms emerge.

The current advancements in clinical trials have escalated the developmental demand for a scale which validates adjustments in FA. The Friedreich Ataxia Rating Scale (FARS) is a disease-specific semi-qualitative assessment which includes three subscales (functional …

Design And Testing Of Experimental Langmuir Turbulence Facilities, Zongze Li

USF Tampa Graduate Theses and Dissertations

Langmuir Circulation is a common phenomenon driven by wind in oceans and lakes and was first studied by Langmuir in 1927. According to various ocean observations, this kind of phenomenon plays an important role in many phenomena such as the aggregation of bubbles, the distribution of plankton as well as the mixing of spilled oil and sediment in the ocean. To study this, an experimental facility has been developed in the lab which creates a small scale version of Langmuir Circulation.

This thesis is about the design and testing of this tank and surrounding aluminum frame, as well as the …

Prioritizing Rehabilitation Of Sanitary Sewers In Pinellas County, Fl, Jesse T. Hillman

USF Tampa Graduate Theses and Dissertations

Following large rain events, extraneous freshwater contributions known as inflow and infiltration (I/I) bypass the storm sewer and enter the sanitary sewer system. In areas with a high water table, like Pinellas County and the surrounding Tampa Bay area, a majority of the wastewater infrastructure is submerged year round exacerbating the rate of groundwater infiltration. This excess flow overloads the existing wastewater infrastructure leading to sanitary sewer overflows (SSOs). These SSOs result in serious problems for municipalities and utilities across the country.

This study was performed in order to assist Pinellas County Utilities in rehabilitating their southern sewer system. To …

Statistical Anomaly Detection And Mitigation Of Cyber Attacks For Intelligent Transportation Systems, Ammar Haydari

USF Tampa Graduate Theses and Dissertations

Secure vehicular communication is a critical factor for secure traffic management. Perfect security in intelligent transportation systems (ITS) has solid and efficient intrusion detection systems (IDS). In this paper, we consider false data injection attacks and distributed denial-ofservice attacks (DDoS), especially the stealth low-rate DDoS attacks, targeting the integrity and availability, respectively, in vehicular ad-hoc networks (VANET). Novel statistical intrusion detection and mitigation techniques are proposed for the considered attacks. The performance of the proposed methods are evaluated using a traffic simulator and a real traffic dataset. Comparisons with the state-of-the-art solutions clearly demonstrate the superior performance of the proposed …

Steady State Hydroplaning Risk Analysis And Evaluation Of Unsteady State Effects, Menna Yassin

USF Tampa Graduate Theses and Dissertations

Hydroplaning is a major concern on high speed roadways during heavy rainfall events. Hydroplaning tools are widely used by designers to reduce their roadway’s hydroplaning potential, therefore reducing the possibilities of severe crashes. This dissertation presents two methodologies for improving the prediction of hydroplaning potential.

The first phase focused on improving an existing widely used software called PAVDRN. Using multiple datasets from the Florida Department of Transportation, the author filtered the data using specific criteria to leave only truly dynamic hydroplaning crashes. The author then evaluated PAVDRN’s prediction capabilities and assessed its reliability in predicting a hydroplaning crash. Using past …

Authentication And Sql-Injection Prevention Techniques In Web Applications, Cagri Cetin

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the top two “most critical web-application security risks” by combining two high-level contributions.

The first high-level contribution introduces and evaluates collaborative authentication, or coauthentication, a single-factor technique in which multiple registered devices work together to authenticate a user. Coauthentication provides security benefits similar to those of multi-factor techniques, such as mitigating theft of any one authentication secret, without some of the inconveniences of multi-factor techniques, such as having to enter passwords or biometrics. Coauthentication provides additional security benefits, including: preventing phishing, replay, and man-in-the-middle attacks; basing authentications on high-entropy secrets that can be generated and updated automatically; …

Characterization Of Geogrid Reinforced Ballast Behavior Through Finite Element Modeling, Bugra Sinmez

USF Tampa Graduate Theses and Dissertations

Recently, the railway pavement structure system, as an integral part of the transport infrastructure, has been under fast development in some countries such as China, Turkey, and some European Union countries, particularly for the use of high-speed trains. In designing and constructing the railway pavement structure, it is necessary to take into account the infrastructure demand of the High-Speed Railway Lines (HSRL). Compared to traditional railway trains, HSRL can cause more significant problems to the ballast or base layer of commonly used ballasted railway pavements. The deteriorated ballast or base layer may further result in substructure degradation that may cause …

Cross Layer-Based Intrusion Detection System Using Machine Learning For Manets, Amar Amouri

USF Tampa Graduate Theses and Dissertations

Intrusion Detection systems plays a crucial role in detecting malicious activities that deteriorate the performance of the network. Mobile AdHoc Networks (MANETs) and Wireless Sensor Networks (WSNs) are a type of wireless networks that can deliver data without any need of infrastructure for their operation. The distributed nature of these networks and the limited resources available, pose a huge challenge for the security of a network. The need for an IDS that can adapt with such challenges is of utmost importance.

Two IDS schemes are presented in this dissertation; the first scheme is based on utilizing the promiscuous mode based …

Phase Evolution And Dynamic Behavior In Materials With Noncollinear Spin Textures, Eleanor M. Clements

USF Tampa Graduate Theses and Dissertations

Noncentrosymmetric magnetic materials have gained special attention due to their ability to stabilize topologically nontrivial magnetic states via the competition between symmetric exchange and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction. The spin struc- tures in these materials have become a center of interest for spintronics applications due to their stable, particle-like properties, and high degree of tunability via control of external parameters, such as magnetic and/or electric field and temperature. Understanding how these robust magnetic structures stabilize, evolve, dynamically respond, and adhere to existing models, all in the presence of external stimuli, are topics of fundamental interest. In this dissertation, the …

Synthesis And Characterization Of Molybdenum Disulfide/Conducting Polymer Nanocomposite Materials For Supercapacitor Applications, Turki S. Alamro

USF Tampa Graduate Theses and Dissertations

The needs for energy storage devices have kindled researchers desire to explore and synthesize nanocomposite materials. Storing energy efficiently, effectively and sustainably are the science and engineering communities’ highest priorities to develop electrochemical energy storage devices. Supercapacitors have become power solution not only because supercapacitors can bridge the gap between the traditional capacitors and rechargeable batteries but also because of many other advantages which include extraordinary electrochemical properties, wide working-temperature range, cost effective, safe operation and long/stable cycle life. They have higher current pules than batteries due to the mechanism of charging and discharging. Batteries charging and discharging via chemical …

Security Framework For The Internet Of Things Leveraging Network Telescopes And Machine Learning, Farooq Israr Ahmed Shaikh

USF Tampa Graduate Theses and Dissertations

The recent advancements in computing and sensor technologies, coupled with improvements in embedded system design methodologies, have resulted in the novel paradigm called the Internet of Things (IoT). IoT is essentially a network of small embedded devices enabled with sensing capabilities that can interact with multiple entities to relay information about their environments. This sensing information can also be stored in the cloud for further analysis, thereby reducing storage requirements on the devices themselves. The above factors, coupled with the ever increasing needs of modern society to stay connected at all times, has resulted in IoT technology penetrating all facets …

Essays On Time Series And Machine Learning Techniques For Risk Management, Michael Kotarinos

USF Tampa Graduate Theses and Dissertations

The Capital Asset Pricing Model combined with the Sharpe ratio is a standard method for choosing assets for selection in a portfolio. However, this method has many structural issues and was designed for a time when high dimensional computing was in its infancy. An alternative to these methods using a mix of Multi-Level Time Series Clustering, the MACBETH algorithm and traditional time series techniques was constructed that minimized data loss and allow for customized portfolio construction for investors with different risk profiles and specialized investment needs. It was shown that these methods are adaptable to cloud computing environments and allow …

Routing And Designing Networks For Two Transportation Problems, Liu Su

USF Tampa Graduate Theses and Dissertations

Routing and designing are essential for transportation networks. With effective routing and designing policies, transportation networks can work safely and efficiently. There are two transportation problems: hazardous materials (hazmat) transportation and warehouse logistics. This dissertation addresses the routing of networks for both problems. For hazmat transportation, the routing can be regulated via network design. Due to catastrophic consequences of potential accidents in hazmat transportation, a risk-averse approach for routing is necessary. In this dissertation, we consider spectral risk measures, for risk-averse hazmat routing. In addition, we introduce a network design problem to select a set of closed road segments for …