Engineering Commons^™

Hybrid Rans-Les Hemolytic Power Law Modeling Of The Fda Blood Pump, Joseph Tarriela

USF Tampa Graduate Theses and Dissertations

This study applies the SBES and IDDES hybrid RANS-LES turbulence models along with the K-ω SST model to four flow conditions of the FDA blood pump. Validation of all three turbulence models show good agreement with experimental pressure and velocity fields. Evaluation of turbulent kinetic energy fields for the hybrid models show 80-90+% of kinetic energy is resolved in the rotor and diffuser regions of the pump. Hemolysis power law models were evaluated using the commonly used von Mises stress and additional energy dissipation stress (EDS). Results show viscous and Reynolds stresses computed with the K-ω SST under predict and …

Magnetic And Structural Effects In Interfacial Magnetism: Molecular Magnets And Ferrimagnetic Alloys, Jenae E. Shoup

USF Tampa Graduate Theses and Dissertations

Magnetic thin films are important for technological applications such as giant magnetoresistance,spin valves and magnetic tunnel junctions. A key feature for these applications to be possible is the interface between two materials. We will be studying two types of thin film magnetism; interfaces between molecular carbon, C60, and non-magnetic/ferromagnetic material and two layers of ferrimagnetic rare earth/ transition metal alloys (RE/TM) that have similar composition to engineer a magnetic tunable interface.

One of the most unexpected spin-related properties of C60 is the emergence of room-temperature ferromagnetism in multilayer films of C60 and non-ferromagnetic transition metals such as Cu or Mn …

Pressure Retarded Osmosis: A Potential Technology For Seawater Desalination Energy Recovery And Concentrate Management, Joshua Benjamin

USF Tampa Graduate Theses and Dissertations

Currently, a significant challenge with reverse osmosis-based desalination is reducing the energy consumption and environmental impacts of the process. This project analyzed the viability of using pressure-retarded osmosis (PRO) for energy recovery in seawater desalination facilities using brine concentrate (the draw solution) and other water sources (the feed solution) such as wastewater effluent. The primary goal of this project is to decrease the cost and overall energy consumption of seawater desalination through PRO-based energy recovery. Process modeling, statistical and sensitivity analysis, energy and cost analysis, geospatial and GIS analysis, laboratory-scale testing, water quality analysis, SEM-EDS microscopy, computational fluid dynamics (CFD), …

Spin Coupling In Magnetic Core - Shell Nanoparticles, Corisa Kons

USF Tampa Graduate Theses and Dissertations

Magnetic nanoparticles (NPs) have garnered much interest due to the unique properties that emergewhen compared to their bulk counterparts. In particular, core-shell (CS) NPs offer the ability to tailor the magnetic properties of the system through careful selection of core and shell constituent materials. In this work, the magnetic ordering of CS NPs with contrast in core/shell features (moment, anisotropy, coercivity, etc.) have been investigated using a combination of X-ray magnetic circular dichroism spectroscopy (XMCD) and polarized small angle neutron scattering (SANS). First, temperature-dependent analyses of XMCD and SANS studies were carried out for CS NPs featuring a core composed …

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 …

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 …

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 …

Flow Visualization And Aerosol Characterization Of Respiratory Jets Exhaled From A Mannequin Simulator, Sindhu Reddy Mutra

USF Tampa Graduate Theses and Dissertations

It is important to understand the airborne transmission of infectious diseases due to the COVID-19 pandemic. Physical experiments were conducted to understand the dispersion of aerosols emitted from a mannequin simulator replicating human tidal breathing through the nose and mouth with and without a protective face mask in an enclosed space. Flow patterns are observed via high-speed visualization, and the concentration and size distribution of the particles is measured as a function of distance from the mannequin using an optical particle sizer. Masks were shown to effectively reduce the horizontal dispersion of aerosol for both mouth and nose breathing. Further, …

Isolation Of Specific Phospholipids From Nannochloropsis Oculata Microalga For Cosmetic Applications, Ahmet Yener Manisali

USF Tampa Graduate Theses and Dissertations

Algae, photosynthetic aquatic organisms, have recently caught the attention of the food, cosmetic, pharmaceutical, and nutraceutical industries due to the variety of natural compounds in their cellular bodies such as carbohydrates, lipids, and proteins. Specifically, microalgae-derived natural compounds such as phospholipids are extensively utilized in cosmetics as part of liposome formers, emulsifiers, solubilizers, and wetting agents. Although phospholipids are currently extracted from food sources, this practice raises sustainability concerns. Hence, growing microalgae on the provision of macronutrients such as nitrates and phosphates will serve as a more sustainable source of the several specific phospholipids such as phosphatidylcholine (PC), phosphatidyl-ethanolamine (PE), …

A Framework For Assessing The Reliability, Availability, Maintainability, And Safety (Rams) Of Decentralized Sanitation, Adefunké Adeosun

USF Tampa Graduate Theses and Dissertations

In established industry sectors, Reliability, Availability, Maintainability, and Safety (RAMS) risk assessments are normally used to compare the risks associated with different technologies on process units. Sanitation solutions are split into traditional wastewater treatment which is centralized treatment and can be classified as an established industry, and decentralized treatment such as pit latrines and septic tank systems which are on much smaller scales. Also they can be classified as non-conventional methods such as reinvented advanced decentralized non-sewered sanitation solution techniques exist mainly in two forms as “Single-User Reinvented Toilet (SURT)” systems or “Multiple-User Reinvented Toilet (MURT)” systems. Advanced decentralized non-sewered …

Laser-Induced Modifications In Two-Dimensional Materials, Tariq Afaneh

USF Tampa Graduate Theses and Dissertations

Atomically thin two-dimensional (2D) materials have attracted a growing interest in the lastdecade from the fundamental point of view as well as their potential applications in functional devices. Due to their high surface-to-volume ratio, the physical properties of 2D materials are very sensitive to the environmental factor such as surrounding media and illumination conditions (e.g. light-mater interaction). In the first part of this dissertation I will present recent advances in developing laser-assisted methods to tune the physical properties of 2D transition metal dichalcogenides (TMDs). We demonstrate laser-assisted chemical modification ultrathin TMDs, locally replacing selenium by sulfur atoms. The photo-conversion process …

Honokiol Loaded Mpeg-Pcl Micelles For The Treatment Of Age-Related Macular Degeneration, Amna Shahid

USF Tampa Graduate Theses and Dissertations

Age related Macular Degeneration (AMD), a multi-factorial age-related retinal hypoxic disorder resulting in irreversible loss of vision is the foremost cause of blindness in United States. Current treatment strategies used to treat disease involve multiple intraocular injections of Anti – VEGF agents into the vitreous of eye. In addition to the issues of drug localization and targeted delivery, the need to frequently inject drug into the eye raise patient compliance issues. These challenges call for sustained drug delivery system. In this study, a sustained drug delivery system was prepared by loading an anti- HIF agent, honokiol into MPEG-PCL polymer. These …

Swimming Of Pelagic Snails: Kinematics And Fluid Dynamics, Ferhat Karakas

USF Tampa Graduate Theses and Dissertations

Pteropods (also known as sea butterflies or sea angels), are holoplanktonic marine snails which swim by flapping a pair of extremely flexible wings. The wings are modified from the molluscan foot and the wing motions are supported by the fluid pressure without any rigid support. Sea angels (gymnosome pteropods) are completely naked; in contrast, sea butterflies (thecosome pteropods) have negatively buoyant aragonite shells which vary in geometry and size among different species. Pteropods are seasonally abundant in the ocean, and an important food source for the other zooplanktons, fishes, and whales. Though studies have been conducted regarding their biology, ecology, …

Study Of The Therapeutic Effects Of Synchronization-Modulation Of The Na/K Pump On Muscle Fatigue, Jason E. Mast

USF Tampa Graduate Theses and Dissertations

It has been shown that by applying a specially designed oscillating external electric field to a cell membrane that the membrane's sodium/potassium pumps can be synchronized to all work at the same rate. Then by slowly increasing the electric field's frequency the pumps' turnover rate can also be increased. By increasing the pumps' turnover rate, the sodium and potassium concentration gradients can be increased, this type of stimulation is called synchronization-modulation. There are three generations of the synchronization-modulation waveform each with different utilities. In particular, the third generation of synchronization-modulation has the ability to use the energy of the external …

Rescue Of Hearing And Protection Of Auditory Structures From Noise-Induced Hearing Loss, Reza Amanipour

USF Tampa Graduate Theses and Dissertations

Hearing loss due to exposure to high level sound is a major health problem that causes permanent hearing impairment and has a significant impact on job productivity and quality of life. A large population suffers from noise-induced hearing loss (NIHL), a disorder for which there is currently no FDA-approved prevention, treatment or cure. The goal of my dissertation work is to provide insights into the effects of noise trauma on hearing abilities of normal hearing subjects, and determine how a new therapeutic compound (mGlu7 modulator) can protect and/or prevent loss of, or damage to sensory cells and brain neurons, including …

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 …

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 …

Heart Rate Variability Analysis As A Means Of Real-Time Hypercapnia Detection, Joseph Dituri

USF Tampa Graduate Theses and Dissertations

The motivation for this research is the high prevalence experienced by divers of carbon dioxide (CO₂) issues and concerns throughout their lives. Additionally, CO₂ is naturally occurring, the product of oxidative metabolism, and is undetectable to human senses. Current CO₂ sensor or detection technology is limited to high-cost machines such as arterial blood gas monitors and end tidal CO₂ monitors, or more modern technology relying upon bright lights which measure blood flow. The light technology is notoriously unreliable and does not produce a very effective heart beat allowing a user to detect minimal changes. Heart …

Simulation Of Radiation Flux From Thermal Fluid In Origami Tubes, Robert R. Bebeau

USF Tampa Graduate Theses and Dissertations

Spacecraft in orbit experience temperature swings close to 240 K as the craft passes from the shadow of the Earth into direct sunlight. To regulate the craft’s internal energy, large radiators eject unwanted energy into space using radiation transfer. The amount of radiation emitted is directly related to the topology of the radiator design. Deformable structures such as those made with origami tessellation patterns offer a mechanism to control the quantity of energy being emitted by varying the radiator shape. Three such patterns, the Waterbomb, Huffman Waterbomb, and Huffman Stars-Triangles, can be folded into tubes. Origami tubes offer greater control …

Integration And Cross-Coupling Of A Notched-Turbine Symbiotic Power Source For Implantable Medical Devices, Samuel Perez

USF Tampa Graduate Theses and Dissertations

The purpose of this research is to design and integrate a symbiotic notched-turbine energy generator for implantation as a cross-coupled system capable of continuously and perpetually powering an electronic implantable medical device (IMD), which is a device designed to operate inside the body of a higher mammal to enhance, correct or provide the body with a function that has deviated from the norm or has stopped altogether. The list of IMDs available for implantation keeps growing every year, one of the newest being the VBLOC, produced by EnteroMedics®, and approved by the Food and Drug Administration (FDA) on January 15th, …

A Novel Framework To Determine Physiological Signals From Blood Flow Dynamics, Prashanth Chetlur Adithya

USF Tampa Graduate Theses and Dissertations

Centers for Disease Control and Prevention (CDC) estimate that more than 11.2 million people require critical and emergency care in the United States per year. Optimizing and improving patient morbidity and mortality outcomes are the primary objectives of monitoring in critical and emergency care. Patients in need of critical or emergency care in general are at a risk of single or multiple organ failures occurring due to a traumatic injury, a surgical event, or an underlying pathology that results in severe patient hemodynamic instability. Hence, continuous monitoring of fundamental cardiovascular hemodynamic parameters, such as heart rate, respiratory rate, blood pressure, …

Computational Discovery Of Energetic Polynitrogen Compounds At High Pressure, Brad A. Steele

USF Tampa Graduate Theses and Dissertations

High-nitrogen-content energetic compounds containing multiple N-N bonds are an attractive alternative towards developing new generation of environmentally friendly, and more powerful energetic materials. High-N content translates into much higher heat of formation resulting in much larger energy output, detonation pressure and velocity upon conversion to large amounts of non-toxic, strongly bonded N2 gas. This thesis describes recent advances in the computational discovery of group-I alkali and hydrogen polynitrogen materials at high pressures using powerful first-principles evolutionary crystal structure prediction methods. This is highlighted by the discovery of a new family of materials that consist of long-sought after all-nitrogen N􀀀 5 …

Organometal Halide Perovskite Solar Absorbers And Ferroelectric Nanocomposites For Harvesting Solar Energy, Chaminda Lakmal Hettiarachchi

USF Tampa Graduate Theses and Dissertations

Organometal halide perovskite absorbers such as methylammonium lead iodide chloride (CH₃NH₃PbI₃-_xCl_x), have emerged as an exciting new material family for photovoltaics due to its appealing features that include suitable direct bandgap with intense light absorbance, band gap tunability, ultra-fast charge carrier generation, slow electron-hole recombination rates, long electron and hole diffusion lengths, microsecond-long balanced carrier mobilities, and ambipolarity. The standard method of preparing CH₃NH₃PbI₃-_xCl_x perovskite precursors is a tedious process involving multiple synthesis steps and, the chemicals being used (hydroiodic acid …

Understanding Gas Sorption Mechanisms In Metal–Organic Materials Via Computational Experimentation, Katherine A. Forrest

USF Tampa Graduate Theses and Dissertations

Metal–organic materials (MOMs), a type of porous crystalline structure composed of organic ligands jointed with metal ions, have captured the interest of scientists as potentially useful in gas sorption applications. Some of the most crucial avenues of investigation are in H2 storage (for use as a clean burning fuel source) and CO2 capture and sequestration (to remove the greenhouse gas from the environment).

A major advantage of MOMs for such applications is their high variability in terms of physical dimensions and chemical moieties, based on composition and synthesis conditions, making them potentially customizable for specific application if necessary structural characteristics …

Algae: Opportunities For Biomass Feedstock Production, Wastewater Treatment And Educational Outreach, Trina Cassandra Halfhide

USF Tampa Graduate Theses and Dissertations

Algae are a diverse group of simple organisms that lack roots, stems or leaves and are able to use sunlight, carbon dioxide, and nutrients to produce complex compounds, such as carbohydrates, proteins and lipids. These compounds, especially lipids, are highly sought-after by agricultural, nutraceutical and energy interests. Although there is great potential for algae derived biofuels, there are technical and economic challenges associated with their cultivation. Relevant to this dissertation, the environmental impacts associated with algae cultivation can be reduced by using municipal and agricultural wastewaters as a water and nutrient source. This research was divided into three sections to …

Future Engineering Professors' Conceptions Of Learning And Teaching Engineering, Ana Teresa Torres Ayala

USF Tampa Graduate Theses and Dissertations

Conceptions of learning and teaching shape teaching practices and are, therefore, important to understanding how engineering professors learn to teach. There is abundant research about professors' conceptions of teaching; however, research on the conceptions of teaching of doctoral students, the future professors, is scarce. Furthermore, there is a need to understand not just future engineering professors' conceptions of teaching but also their conceptions of learning. The purpose of this study was to explore qualitative variations in future engineering professors' conceptions of learning and teaching as well as understanding how they came to these conceptions.

The research questions that guided this …

Assessing Appropriate Technology Handwashing Stations In Mali, West Africa, Colleen Claire Naughton

USF Tampa Graduate Theses and Dissertations

Proper hand hygiene is the most effective and efficient method to prevent over 1.3 million deaths annually from diarrheal disease and Acute Respiratory Infections (ARIs). Hand hygiene is also indispensable in achieving the fourth Millennium Development Goal (MDG) to reduce the childhood mortality rate by 2/3rds between 1990 and 2015. Handwashing has been found in a systematic review of studies to reduce diarrhea by 47%#37; and is, thus, capable of preventing a million deaths (Curtis et. al., 2003). Despite this evidence, hand washing rates remain seriously low in the developing world (Scott et al., 2008).

This study developed and implemented …

Development Of Novel Nano-Composite Membranes As Introduction Systems For Mass Spectrometers: Contrasting Nano-Composite Membranes And Conventional Inlet Systems, Luis Miranda

USF Tampa Graduate Theses and Dissertations

This dissertation presents the development of novel nano-composite membranes as introduction systems for mass spectrometers. These nano-composite membranes incorporate anodic aluminum oxide (AAO) membranes as templates that can be used by themselves or modified by a variety of chemical deposition processes. Two types of nano-composite membranes are presented. The first nano-composite membrane has carbon deposited within the pores of an AAO membrane. The second nano-composite membrane is made by coating an AAO membrane with a thin polymer film. The following chapters describe the transmission properties these nano-composite membranes and compare them to conventional mass spectrometry introduction systems. The nano- composite …

Investigating The Role Of The Internet In Women And Minority Stem Participation: A Case Study Of Two Florida Engineering Programs, Arland Nguema Ndong

USF Tampa Graduate Theses and Dissertations

Despite our awareness of the fascination modern humans have with the Internet, little is known about how and why colleges and universities create and maintain Websites. At the most general level, in this case study, I hypothesize that university Websites serve as communication and marketing tools in attracting students. At the most specific level, I postulate that civil engineering programs with Web pages depicting images of women and minorities would be more successful in recruiting and retaining women and students of color than civil engineering programs with Web pages displaying fewer or no images of women and minorities. The primary …