Engineering Commons^™

Minimum Cut-Sets For The Identification Of Critical Water Distribution Network Segments, Xiliang Mao

USF Tampa Graduate Theses and Dissertations

To ensure adequate performance of water distribution networks, utilities must identify critical segments within the network that will adversely affect users when failures occur. Currently, time consuming hydraulic simulations are used for such criticality analyses. A method can be of great benefit for utilities if it can easily evaluate the criticality of water distribution network segments. This research applies topology-based methods for the preliminary screening of critical segments. This study evaluated the connectivity between sources and each demand segment in water distribution networks using minimum cut-sets. Through topological analysis, the minimum cut -set between the source node and each demand …

Multi-Material Hybrid Additive And Subtractive Manufacturing Of Photonic Devices, Roger Brandon Tipton

USF Tampa Graduate Theses and Dissertations

Optoelectronics focuses on the application of electronic devices that utilize forms of electromagnetic radiation including visible light and other wavelengths including ultraviolet and infrared. Optoelectronics typically include devices that emit light and detect light. Devices created using this technology include light-emitting diodes, laser diodes, photoresistors, photodiodes, solar cells, phototransistors, and fiber optics. Fiber optic interconnects are interesting devices in that they are used in conjunction with optoelectronic devices to transmit information between individual optoelectronic components.

Optoelectronics are typically produced by traditional lithography methods including etching, writing, and printing on rigid silicon substrates for fabricating devices. Other techniques like glass or …

Design Of Acoustic Wave Sensor System For Detection Of Btex In Gas Phase, Veselinka Mitevska

USF Tampa Graduate Theses and Dissertations

Benzene, toluene, ethylbenzene, and xylene are classified as volatile organic compounds (VOC), which if present at higher concentrations can cause acute and/or chronic health effects. To protect people from VOCs, the occupational safety and health agency (OSHA) established short term and eight-hour workday exposure limits. The short time levels of exposure for BTEX materials are 5 ppm, 150 ppm, 125 ppm, and 150 ppm, for benzene, toluene, ethylbenzene, and xylene respectively. The eight-hour workday exposure for these same materials are 1 ppm for benzene, 200 ppm for toluene, 100 ppm for ethylbenzene and 100 ppm for xylene. Although there are …

Effects Of Nitrate On Arsenic Mobilization During Aquifer Storage And Recovery, Hania Hawasli

USF Tampa Graduate Theses and Dissertations

Aquifer storage and recovery technology is used to sustain water resources and to prevent saltwater intrusion. The injected water can come from various resources, including treated wastewater. In pilot ASR studies in the Tampa Bay region, researchers found high As concentrations in the recovered water from the oxidation of the arsenopyrite that is embedded in the aquifers. The presence of dissolved O2 in the injected water is a major factor in the arsenopyrite oxidation during ASR, however the effects of NO3- on the arsenopyrite has not been studied yet. This is an important knowledge gap because injected water may contain …

Polyethyleneimine-Based High Yield Fluorescent Soluble Covalent Organic Framework, Haonan Wang

USF Tampa Graduate Theses and Dissertations

In this thesis, we report a novel covalent organic framework (COF) with fluorescence and water-soluble features, F-COF-PT with high gravimetric yield (~ 89%), that was generated by the reactions of branched polyethyleneimine (PEI) and 1,3,6,8-Tetrabromopyrene (TBP). The surface area and pore volume were about up to 63.2 m2/g and 0.41 m3/g. The prepared COFs maintained the TBP fluorescent performance in water solutions at 440-460 nm. Furthermore, Cu(II) ion solution would impact the quenching activity with F-COF-PT3, and NaOH treated F-COF-PT3 has the 5.6 m2/g capacity of uptake CO2. Finally, the zeta potential and particle diameter of original and treated F-COF-PT3s …

Plasma Treatment Of High-Density Polyethylene, Linear Low-Density Polyethylene, And Polyvinyl Chloride Geomembranes By Air And Oxygen, Merve Koca Uyar

USF Tampa Graduate Theses and Dissertations

High-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and polyvinyl chloride (PVC) geomembranes were treated with air and oxygen plasma. The purpose of air and oxygen plasma treatment of geomembrane surface is to increase the surface wettability of these materials, thereby increasing adhesive properties. Increasing adhesive properties enables a surface to be coated with a desired material with antibacterial, antioxidant, and UV resistant characteristics, without changing bulk material properties. To protect the geomembranes from oxidation degradation, UV degradation and biological degradation, it is important to increase the antibacterial, antioxidant, and UV resistant properties of geomembrane. Before and after the plasma treatments …

Modeling The Ambient Conditions Of A Manufacturing Environment Using Computational Fluid Dynamics (Cfd), Yang Liu

USF Tampa Graduate Theses and Dissertations

As manufacturing equipment evolve to higher speed and require high precision operations, the impact of environmental changes on machine accuracy becomes critical. Due to thermal expansion, the structure of the machine can change when ambient temperature varies. When the airflow in the laboratory changes, this also alters the operator's thermal comfort. Either the change in machine structure or operator comfort can ultimately affect machine accuracy. The manufacturing industry is currently using heating, ventilation, and air-conditioning (HVAC) systems to regulate the temperature of the working environment. However, since conventional HVAC systems determine whether to activate the HVAC system by collecting the …

Material And Topographically Optimized Thermal Dissipation For High-Performance Electronic Devices Utilizing Vapor Chambers, Derek Joseph Daniels

USF Tampa Graduate Theses and Dissertations

Advances in materials science and engineering in the field of thermal transport and dissipation enable the use of higher-performance electronic devices that are smaller and generate more heat. Phase change thermal transport systems such as heat pipes and vapor chambers enable passive dissipation from devices that generate excessive heat without the need for actively pumped cooling systems. Properly designed vapor chamber enabled systems easily exceed the thermal conductivity of manufactured diamond at a small fraction of the cost.[1][2][3] While heat pipe phase change systems are generally one-dimensional with a limited cross section, vapor chambers are generally two-dimensional with a small …

Texturing In Bi2Te3 Alloy Thermoelectric Materials: An Applied Physics Investigation, Oluwagbemiga P. Ojo

USF Tampa Graduate Theses and Dissertations

Thermoelectric devices provide the means for direct conversion between heat and electricity. The device conversion efficiency, or performance, is directly related to the thermoelectric figure of merit, ZT, of the working materials. Bismuth telluride alloys are the materials currently in use in most thermoelectric devices for near room temperature solid-state refrigeration and power conversion applications. The vast majority of publications in the literature on thermoelectricity report on investigations towards developing new materials with enhanced thermoelectric properties, however Bi₂Te₃ alloys have been used in thermoelectric devices for decades.

In this thesis, an investigation of crystallographic texturing on large …

Computer Simulation For Continuous Centrifugation Of High-Density Cell Cultures, Hironori Tomizawa

USF Tampa Graduate Theses and Dissertations

Perfusion bioreactors are used for cell production for cell therapies. The system uses cell separation devices such as centrifuge to facilitate cell growth by separating cells and spent media and allows constant media replacement. However, current cell separation technologies can increase shear stress, are generally not continuous processes, and are not as efficient as desired. These limit the amount of media replaced per unit time. Therefore, there is a need for a new system or a method that operates continuously to minimize cell damage, yield high cell concentration, and exchange media effectively. A set of research questions was formulated: (1) …

Constructing Frameworks For Task-Optimized Visualizations, Ghulam Jilani Abdul Rahim Quadri

USF Tampa Graduate Theses and Dissertations

Visualization is crucial in today’s data-driven world to augment and enhance human understanding and decision-making. Effective visualizations must support accuracy in visual task performance and expressive data communication. Effective visualization design depends on the visual channels used, chart types, or visual tasks. However, design choices and visual judgment are co-related, and effectiveness is not one-dimensional, leading to a significant need to understand the intersection of these factors to create optimized visualizations. Hence, constructing frameworks that consider both design decisions and the task being performed enables optimizing visualization design to maximize efficacy. This dissertation describes experiments, techniques, and user studies to …

Dynamical System And Parameter Identification For Power Systems, Abdullah Abdulrahman Alassaf

USF Tampa Graduate Theses and Dissertations

The complexity of dynamical analysis has been growing to suffice the understanding and modeling of dynamical systems. Besides its nonlinearity and high-dimensionality, the dynamics of power systems contain uncertainty that complicates its analysis. Recently, dynamical modeling has been categorized into three types: white-box, black-box, and gray-box. White-box modeling has the accessibility of all system components. Black-box modeling has the observability of the system measurements without knowing the actual system. Gray-box modeling has the observability of the system measurements with the reachability to some of the system components. The scope of this dissertation focuses on black-box and gray-box models to achieve …

Development Of Carbon And Silicon Carbide Based Microelectrode Implantable Neural Interfaces, Chenyin Feng

USF Tampa Graduate Theses and Dissertations

The use of neural modulation techniques to treat nervous system disorders, as well as neural recording to study brain function, continues to be of intense interest around the world. Due to the need to treat diseases such as Parkinson’s, dementia, depression and return normal function to patients suffering from nervous system damage and trauma, neural implants continue to be developed globally. One of these devices, the microelectrode implantable neural interface (mINI), has been rapidly developed, thanks to advanced semiconductor fabrication processes. However, the long-term reliability of present-day devices has still to be demonstrated and is delaying the application of this …

Water Regulation For Enhancing Soil Quality Using Cactus Mucilage: A Theoretical And Experimental Analysis, Khuloud Alrashdi

USF Tampa Graduate Theses and Dissertations

As water is one of the primary sources of life, it is essential in an endless number of systems and processes to be utilized efficiently in nature and in practical applications. One of these applications includes farming, which depletes a lot of water as the water irrigation systems cover large soil areas. While water is a critical factor in growing crops, a question here stands, can the irrigation process be transformed? This is the overarching goal of my work since it is centered on studying if cactus mucilage, a natural substance, is capable of improving water absorption processes on crops …

Adaptive Mobile Eeg Noise Cancellation Using 2d Convolutional Autoencoders For Bci Authentication, Tyree Lewis

USF Tampa Graduate Theses and Dissertations

Electroencephalography (EEG) signals can be used for many purposes and has the potential to be adapted to various systems. When EEG is recorded from users, these studies are performed primarily in an indoor environment, while the user is stationary. This is due to the levels of noise that are experienced when recording EEG data, to minimize errors in the data. This thesis aims to adapt tasks that are performed indoors to an external environment by removing both noise and artefacts in EEG, using a 2D Convolutional Autoencoder (CAE). The data is recorded from subjects is passed into the 2D CAE …

Computational Fluid Dynamics (Cfd) Analysis Of The Hydraulic Performance And Bio-Kinetics In A Full-Scale Oxidation Ditch, Kiesha C. Pierre

USF Tampa Graduate Theses and Dissertations

An oxidation ditch is a biological wastewater treatment unit process where microorganisms are utilized to transform organic matter, and nitrogen from wastewater to meet the desirable effluent concentrations. Mechanical aerators are part of these biological reactors facilitating oxygen transfer for the aerobic microorganisms, while agitating and circulating the phase constituents within the ditch. Modeling the performance of an oxidation ditch involves combining hydrodynamics, oxygen mass transfer, and bio-kinetics and is one of the grand challenges that is of paramount importance in optimization of design and operations of these facilities in an energy efficient way while meeting the targeted effluent concentrations. …

Mutational Analysis Of Latency Associated Peptide For Therapeutic Application, Johnny Will Stephens

USF Tampa Graduate Theses and Dissertations

TGF-β is an important protein for regulation of the immune system, and has been linked to promotion of tumor progression and cancer growth. Inhibiting TGF-β has been shown to be an effective therapeutic technique for fighting multiple cancer types. Engineering TGF-β’s natural inhibitor, Latency Associated Peptide (LAP), to improve its biophysical properties has potential to increase therapeutic efficacy.

Rosetta and FoldX can be used in concert to engineer stabilizing mutations of proteins. In accordance with this, PyRosetta and FoldX were used to predict stabilizing mutations of LAP. The most stabilizing mutations from each program were combined with mutually predicted mutations. …

Fiber-Based Supercapacitor For Wearable Electronics, Rohit Lallansingh Yadav

USF Tampa Graduate Theses and Dissertations

Supercapacitors are significant devices that are used for energy storage and also have the capability of delivering energy at a faster rate than batteries. The increase in the significance of portable and wearable electronic equipment giving rise to pace in the development of flexible supercapacitor and flexible electrodes in recent years. A fiber-based supercapacitor (FSCs) is one of the most significant devices which have even helped us give pace knowing the properties of supercapacitor. These FSCs are said to have excellent electrochemical properties and flexibility. This did make function it in different forms of individual fibers or integrated textiles which …

Preparation And Characterization Of Single Layer Conducting Polymer Electrochromic And Touchchromic Devices, Sharan Kumar Indrakar

USF Tampa Graduate Theses and Dissertations

Electrochromic devices (ECDs) have triggered great interest because of their potential applicability in energy-efficient buildings and low power display systems, including reflective type smart windows/mirrors and wearable-flexible devices. In the past decades, electrochromic technologies with different device structures and materials have been proposed. The idea of employing a simple device structure with a durable, cost effective electrolyte is crucial to designing and manufacturing high-performance ECDs. With this idea in mind, this thesis describes the various efforts to develop a simple ECD comprising of a composite single active layer gel electrolyte, sandwiched between two transparent conducting electrodes, lasting over 10,000 cycles …

Security Attacks And Defenses In Cyber Systems: From An Ai Perspective, Zhengping Luo

USF Tampa Graduate Theses and Dissertations

Security of real-world cyber systems has drawn a lot of attention in recent years, especially when machine learning techniques are widely deployed into different layers of cyber systems. With the technology of machine learning, especially adversarial machine learning techniques, the attacks and defenses in cyber systems have shown a lot of new characteristics. In this dissertation, two major works regarding the attacks and defenses in real world cyber systems including dynamic spectrum sensing systems and High Performance Computing (HPC) systems and software systems are discussed.

In the first work, we revisit this security vulnerability of cooperative spectrum sensing as an …

Secure Vlsi Hardware Design Against Intellectual Property (Ip) Theft And Cryptographic Vulnerabilities, Matthew Dean Lewandowski

USF Tampa Graduate Theses and Dissertations

Over the last two decades or so, VLSI hardware is increasingly subject to sophisticated attacks on both the supply chain and design fronts. There is no explicit trust that the manufacturers/providers are not producing counterfeit designs or that cryptographic algorithms we know to be secure in software are also secure in hardware. The novelty and key contributions of this work are as follows: 1) a continually refined method for Intellectual Property (IP) Protection that provides an approach for verification of IP ownership, 2) demonstrate how to break the PRESENT-80 cryptographic algorithm with significantly limited resources, and 3) provide a multitude …

Advanced Organic Polymers For The Nanoscale Fabrication Of Fiber-Based Electronics Using The Electrospinning Technique, William Serrano Garcia

USF Tampa Graduate Theses and Dissertations

Electrospinning has become one of the most interesting techniques for fabricating nanofibers for multiple applications. The high surface-to-volume ratio nanofibers offer make the perfect structure for filters, sensors, and fiber-based electronics that could lead to a wide range of flexible electronics applications. This technique makes organic semiconducting polymers a promising alternative for single fiber electronics structures. Indeed, a wide variety of structures can be fabricated using electrostatic techniques for polymer manipulation from droplets, fibers, and coaxial structures. Although techniques such as electrospinning led the use of electrostatic forces to generate fibers of a precursor solution, electrospinning requires large enough polymer …

Healthcare Data Analytics For Predicting Health Outcomes Of Older Adults And Emergency Responses Of Aged Care Facilities, Nazmus Sakib

USF Tampa Graduate Theses and Dissertations

The United States (US) is experiencing rapid growth in its older adult population, who may suffer from multiple chronic diseases, injuries, and impairments. To meet with the excess demand without compromising the quality of care for older adults, the current aged care systems, such as nursing home systems, will face unprecedented challenges of healthcare resource shortage with rising costs. Accurate prediction of health outcomes of individual older adults will facilitate the aged care professionals to better prioritize healthcare resources for the most at-risk individuals with more focused care and provide more proactive and individualized treatment and care delivery. In addition, …

Biochar Amended Bioretention Systems For Nutrient And Fecal Indicator Bacteria Removal From Urban And Agricultural Runoffs, Md Yeasir Arif Rahman

USF Tampa Graduate Theses and Dissertations

Excessive nitrogen and fecal indicator bacteria (FIB) in stormwater runoff from urban areas or dairy farm operations impair water bodies resulting algal blooms, gastrointestinal illness, and economic losses. Recent advancements in stormwater management, including low impact development (LID) techniques, have provided engineers with a variety of tools to use in place of traditional catch basins and retention ponds. One promising LID technology for runoff management is bioretention, which consists of a shallow depression containing engineered porous media and vegetation. Prior studies have shown that modified bioretention systems that include an internal water storage zone (IWSZ) to promote denitrification can improve …

Automated Wound Segmentation And Dimension Measurement Using Rgb-D Image, Chih-Yun Pai

USF Tampa Graduate Theses and Dissertations

Accurate pressure ulcer (PrU) measurement is critical in assessing the effectiveness of PrU treatment. The traditional measurement process is manual, subjective, and requires frequent contact with the wound. The manual measurement relies on human observation which makes the measurement inconsistent, and the frequent contact with the wound increases risk of contamination or infection. The purpose of this research was to develop an automatic Pressure Ulcer Monitoring System (PrUMS) using a depth camera to provide automated, non-contact wound measurement. In this dissertation, 1) a wound segmentation with traditional machine learning method, which combines the color classification using K-Nearest Neighbors and the …

Data-Oriented Approaches Towards Mobile, Network And Secure Systems, Shangqing Zhao

USF Tampa Graduate Theses and Dissertations

With the rapid evolvement of information science, data-oriented research has solicited a new philosophy for the future mobile network and security design, since it can not only encourage new designs achieving more efficient and reliable networks, but also pose new challenges towards security designs. In this dissertation, we propose four novel data-oriented designs or frameworks to prompt or calibrate the performance with respect to efficiency, reliability, and security.

In the wireless domain, packet corruption and packet collision are two major threats that jeopardize the performance of a mobile network. To cope with the packet corruption, we propose the STAteful inter-Packet …

Investigation Of Polymer-Plasticizer Blends For Btex Detection Using Quartz Crystal Microbalance, Abhijeet Iyer

USF Tampa Graduate Theses and Dissertations

Volatile organic compounds (VOCs) are chemicals that evaporate easily and become gases at ambient temperature and pressure. The EPA has made the monitoring of VOCs mandatory due to their health impacts, which range from headaches and nausea to cancer. The current techniques used for VOC monitoring such as photoionization, gas chromatography, mass spectroscopy, and e-noses sensors are expensive, time-intensive, demand rigorous sample preparation, and cannot quantify the VOCs in the air. Chemical sensors based on piezoelectric transduction like the quartz crystal microbalance (QCM) show promising results in terms of providing cost-effective real-time data, robustness, and low power requirements. In this …

Event-Triggered Control Architectures For Scheduling Information Exchange In Uncertain And Multiagent Systems, Stefan Ristevski

USF Tampa Graduate Theses and Dissertations

Despite the numerous advantages that networked controlled systems provide, potential network overload in these systems can severely degrade their performance and even cause catastrophic failures. To this end, the work presented in this dissertation provides a neat solution on reducing network utilization in uncertain networked controlled systems using an adaptive event-triggered control approach predicated on a novel dynamical threshold and information exchange methodology while guaranteeing closed-loop system stability.

In particular, consider a system consisting of an operator (e.g, a ground station) and an uncertain controlled dynamical system (e.g., a vehicle equipped with feedback control algorithm), where the aim of the …

Interrelation Of Thermal Stimulation With Haptic Perception, Emotion, And Memory, Mehdi Hojatmadani

USF Tampa Graduate Theses and Dissertations

Haptics is an interdisciplinary field of science that deals with how humans perceive and respond to different sensory cues perceived through touch. Thermal haptics as a branch deals with how humans perceive the temperature sensation and respond to that. The process in which thermal perception occurs is well known to researchers. What seems missing in the literature is how temperature interacts or sometimes intervenes in other physiological and psychological aspects of our lives. In this research, a series of studies are presented where the main focus was how temperature and brain interact with each other to impede or enhance our …

Development Of A Bipolar Radiofrequency Ablation Device For Renal Denervation, Noel Perez

USF Tampa Graduate Theses and Dissertations

The American Heart Association (AHA) reported in March 2020, hypertension (HT) is a major risk factor for cardiovascular diseases and heart stroke. Resistant hypertension (RH) is a subset of HT and affects 11-16% of hypertensive patients. RH is diagnosed when a patient cannot achieve blood pressure control despite taking three or more medications and is a serious clinical management challenge.

Renal denervation (RD) using radiofrequency (RF) ablation is an accepted form of RH therapy. RD devices are typically delivered through femoral access into the renal artery with the assistance of a standard guided sheath. In the European Union (EU), the …