Engineering Commons^™

Controlling And Monitoring Voice Quality In Internet Communication, An Thanh Le

USF Tampa Graduate Theses and Dissertations

The Voice over Internet Protocol (VoIP) is on its way to surpassing toll quality. Although VoIP shares its transmission channel with other communication traffic, today internet has a wider bandwidth than the legacy Digital Loop Carrier and voice could be digitized higher than traditional 8 kbps, to say 16 kbps. Thus, VoIP should not be limited by the toll quality. However, VoIP quality could go down, as a result of unpredictable traffic congestion and network imperfections. These two situations cause delay jitter and packet loss of VoIP. To overcome these challenges, there are ongoing works for service providers including but …

The Sustainability Of Ion Exchange Water Treatment Technology, Adib Amini

USF Tampa Graduate Theses and Dissertations

This research investigated using a life cycle environmental and economic approach to evaluate IX technology for small potable water systems, allowing for the identification and development of process and design improvements that reduce environmental impacts and costs. The main goals were to evaluate conventional IX in terms of life cycle environmental and economic sustainability, develop a method for improving designs of IX systems from a environmental and economic sustainability standpoint, evaluate potential design improvements, and make the research findings accessible to water professionals through user-friendly tools and frameworks that take into account their feedback. This research provides an understanding, from …

Molecular-Size Selective Zeolite Membrane Encapsulated Novel Catalysts For Enhanced Biomass To Liquid (Btl) Processes, Ummuhan Cimenler

USF Tampa Graduate Theses and Dissertations

80% of energy usage in the word comes from fossil fuels (coal, oil, natural gas) and among the fossil fuels, oil is the most consumed energy source especially in transportation. However, due to concerns about energy demand and energy sustainability, global warming and dependency on foreign oil, generation of renewable fuels is crucial for transportation. Biomass to Liquid (BTL) is a promising process available to produce renewable liquid fuels. BTL fuels have great potential to meet the growing demand for liquid fuels, mitigating climate change, and providing value to rural areas. However, there are two major challenges with biofuels produced …

Strategies For Reducing Preventable Hospital Readmissions On Medicare Patients, Andres Patricio Garcia-Arce

USF Tampa Graduate Theses and Dissertations

The high expenditure of healthcare in the United States (U.S.) does not translate into better quality of care. Indeed, the U.S. healthcare system is recognized by its lack of efficiency and waste (which represents about 20% of the country’s healthcare expenses). Lack of coordination is one of the most referenced causes of waste in the U.S. healthcare system, and preventable hospital readmissions have been acknowledged to be evidence of poor coordination of care. In fiscal year 2013, the Centers for Medicare and Medicaid Services (CMS) established financial penalties for inpatient care reimbursements in hospitals with excessive readmissions. All the same, …

Plasmonic Stimulation Of Electrically Excitable Cells, Fnu Parveen

USF Tampa Graduate Theses and Dissertations

There is a compelling need for the development of new sensory and neural prosthetic devices which are capable of more precise point stimulation. Current prosthetic devices suffer from the limitation of low spatial resolution due to the non-specific stimulation characteristics of electrical stimulation, i.e., the spread of electric fields generated. We present a visible light stimulation method for modulating the firing patterns of electrically-excitable cells using surface plasmon resonance phenomena. In in-vitro studies using gold (Au) nanoparticle-coated nanoelectrodes, we show that this method (substrate coated with nanoparticles) has potential for incorporating the technology into neural stimulation prosthetics, such as cochlear …

Optimization And Performance Study Of Select Heating Ventilation And Air Conditioning Technologies For Commercial Buildings, Rajeev Kamal

USF Tampa Graduate Theses and Dissertations

Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times.

Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings:

1. Use of gas heat …

Sorption Of Benzene, Dichloroethane, Chloroform And Dichloromethane By Polyethylene Glycol, Polycaprolactone And Their Copolymers At 298.15 K Using A Quartz Crystal Microbalance, Abhijeet Radhakrishna Iyer

USF Tampa Graduate Theses and Dissertations

Quartz crystal microbalances (QCM) are acoustic wave sensor systems which are used majorly for vapor and liquid sensing. QCM come under the category of thickness shear mode (TSM) sensors. There are several methods to study organic vapor sensing; the QCM method is the one that offers the highest sensitivity and generates the most data. Solubilities of benzene, dichloroethane, chloroform and dichloromethane in polyethylene glycol (PEG), polycaprolactone (PCL), and several di-block PEG/PCL copolymers at 298.15 K are reported. There are literature data available for most of the solvents in the homopolymers PEG and PCL but no literature data is available for …

Mechanism Of Cathodic Prevention Of Carbon Steel In Concrete, Krittin Rattakham

USF Tampa Graduate Theses and Dissertations

In this work, I aim to clarify the mechanism that allows steel to attain higher chloride threshold as it is cathodically polarized. Specifically, I seek to provide empirical information on whether an intrinsic (predominantly interfacial effects of polarization) or an extrinsic (predominantly concentration changes due to polarization) mechanism may be dominant in the beneficial effect of polarization. I carried out this experiment with 12 identical concrete specimens, each with a cast-in steel plate, constantly exposed them to high-chloride environment. The specimens were divided into 4 triplicates and polarized at 4 different level from OCP, -200, -300 to -400 mV_{SCE …}

Tunable Combline Filter And Balun: Design, Simulation, And Test, Daniel Alex Ramirez

USF Tampa Graduate Theses and Dissertations

Reconfigurable filters are an attractive solution for many military and commercial applications due to their ability to alter the partitioned frequency band in an RF system without requiring a bank of fixed filters. The onset of this technology has the potential to revolutionize the RF industry by allowing for agile devices which consume less size, weight, and power while providing greater performance. However, at the present state, reconfigurable filters present a reduction in performance when compared to filter banks. This has led to exciting research in the field of RF tunable filters.

For many applications, planar reconfigurable filters have been …

Failure Analysis Of High Nickel Alloy Steel Seal Ring Used In Turbomachinery, Wenbo Wang

USF Tampa Graduate Theses and Dissertations

The system of upper high nickel alloying steel seal ring and lower high nickel alloying steel seal ring, installed in the grooves of turbine, can extend out and fit with the wall of valve cage, resulting in forming a good seal under the pressure. In the project, the failure steel seal ring is considered. This situation had threatened the safety of the whole steam turbine system. The purpose of this study is to identify the failure cause of the steel seal ring used in nuclear steam turbines. New high nickel steel alloy seal ring was compared with the failed seal …

A Study Of Corrosion Monitoring Techniques Used In Urls For Metals, Sirui Li

USF Tampa Graduate Theses and Dissertations

With the increasing use of fission-type nuclear power generation, particularly high-levels radioactive nuclear waste are generated, so the safe use of nuclear energy requires proper disposal of high-level radioactive nuclear waste. The selected treatment method is deep geological disposal. Therefore, underground research laboratory (URL) to prepare for deep geological disposal will also be carried out. Corrosion of metallic materials, which are closely related to the safety of URL, is the focus of this research project. This study selected monitoring techniques for URL and developed a rough monitoring scheme for temperature and resistivity in URL. In this study, corrosion-temperature and corrosion-resistivity …

Light Olefin Production By Cracking Nannochloris Oculata Microalgae Using Aluminosilicate Catalysts, Gaurav Goyal

USF Tampa Graduate Theses and Dissertations

The global demand and sustainability concerns for producing light olefins encouraged researchers to look for an alternative and sustainable feedstock. Alkenes, such as ethene, propene and butene, are known as light olefins. Olefins are the backbone of the chemical industry because they serve as the chemical building blocks for the manufacture of polymers, fibers, and numerous organic chemicals. Feedstocks such as naphtha, natural gas and liquefied petroleum gas (LPG) are currently used for producing light olefins, but they are non-renewable and hence unsustainable. In contrast, biomass as a potential feedstock for the production of fuels and chemicals is renewable. Microalgae, …

Simulation Studies On Ecg Vector Dipole Extraction In Liquid Medium, Pratheek Michael

USF Tampa Graduate Theses and Dissertations

To circumvent some inherent problems in the conventional ECG, this research reinvestigates an ‘unassisted’ approach which enables ECG measurement without the placement of leads on the body. Employed in this research is a widely accepted assumption that the electrical activity of the heart may be represented, largely, by a 3-D time-varying current dipole (3D-CD). From the PhysioBank database, mECG and fECG data were obtained, and Singular Value Decomposition (SVD) was performed to estimate the time-varying Vector ECG dipole. To determine the sensing matrix responsible for transforming the activity of the 3D-CD into the potential distribution on the surface of the …

Effects Of Microstructure And Alloy Concentration On The Corrosion And Tribocorrosion Resistance Of Al-Mn And We43 Mg Alloys, Hesham Y. Saleh Mraied

USF Tampa Graduate Theses and Dissertations

The design of new engineering materials resistant to both wear damage and corrosion degradation becomes increasingly demanding in complex service conditions. Unfortunately, there is typically a tradeoff between wear and corrosion resistance, even for important passive metals such as Al alloys. This is because the presence of precipitates hardens the material but at the same time lead to unfavorable galvanic coupling between the precipitates and the matrix, resulting in accelerated corrosion. This work showed that Al (or Mg) supersaturated solid solution formed using non-equilibrium methods exhibited enhanced corrosion resistance without compromising strength. For Al, alloying with Mn up to ~ …

Interference Mitigation, Resource Allocation And Channel Control Techniques For 4g And Beyond Systems, Mustafa Harun Yilmaz

USF Tampa Graduate Theses and Dissertations

The usage of the wireless communication technologies have been increasing due to the benefits they provide in our daily life. These technologies are used in various fields such as military communication, public safety, cellular communication. The current systems might not be sufficient to meet the increasing demand. Therefore, the new solutions such as the usage of smart antennas have been proposed to satisfy this demand. Among different solutions, cognitive heterogeneous networks (HetNets) have been recently introduced as a promising one to meet the high user demand. In cognitive Hetnets, there are secondary base stations (SBSs) with secondary users (SUs) and …

Fatty Acid Biomarker Detection For Breast Cancer Using Differential Mobility Spectrometry With Non-Radioactive Ion Source, James Joseph Alberti

USF Tampa Graduate Theses and Dissertations

Differential Mobility Spectrometry (DMS) using a non-radioactive ion source (NRIS) is investigated as a possible medical diagnostic instrument for near real-time detection of breast cancer biomarkers. In previous clinical studies, concentrations of Linoleic, Palmitic and Stearic fatty acids have been observed at different levels in women with carcinoma breast cancer versus women with benign tumors or healthy women showing no signs of breast cancer. Present diagnostic methods require a biopsy of the suspect tissue and a microscopic lab analysis performed to determine its disease state. This process can take hours or days before the patient and doctor are informed of …

Heat Flux Modeling Of Asymmetrically Heated And Cooled Thermal Stimuli, Matthew Hardy

USF Tampa Graduate Theses and Dissertations

Thermal sensation is one of the most dynamic stimulus-response systems in the human body. It is relied upon for safety, comfort and general equilibrium of the human body. Thermal sensation is dependent upon many variables such as area of effected skin, rate of temperature change and location of stimulation. It has been shown that certain rates of change can intensify the sensation of heating or cooling. Conversely, sufficiently low rates of change can go undetected by the skin. As such, the thermal response system can be manipulated by the proper combination of applied hot and cold stimuli. Previous research has …

Media Velocity Considerations In Pleated Air Filtration, Frederik Carl Schousboe

USF Tampa Graduate Theses and Dissertations

Asset protection in the form of fluid filtration makes up an ever-increasing part of the civilized and industrialized world. Fluid filtration applications in the conditioned environment and life sciences are affording the world’s population a chance to better realize their potential, while industrial applications help ensure that high demand processes can be carried out safely, reliably, and effectively.

In the present work, a tool has been developed, using the computational fluid dynamics package FLUENT, to allow the designer to better predict the magnitude of geometric imperfections within a given pleat configuration.

Pleated rectangular filters, intended to improve the quality of …

Orthoplanar Spring Based Compliant Force/Torque Sensor For Robot Force Control, Jerry West

USF Tampa Graduate Theses and Dissertations

A compliant force/torque sensor for robot force control has been developed. This thesis presents methods of designing, testing, and implementing the sensor on a robotic system. The sensor uses an orthoplanar spring equipped with Hall-effect sensors to measure one component of force and two moment components. Its unique design allows for simple and cost effective manufacturing, high reliability, and compactness. The device may be used in applications where a robot must control contact forces with its environment, such as in surface cleaning tasks, manipulating doors, and removing threaded fasteners. The compliant design of the sensor improves force control performance and …

Simulation Of Hemiparetic Function Using A Knee Orthosis With Variable Impedance And A Proprioception Interference Apparatus, Christina-Anne Kathleen Lahiff

USF Tampa Graduate Theses and Dissertations

Individuals with stroke have neuromuscular weakness or paralysis on one side of the body caused by some muscles disengaging and overexciting other muscles. Hyperextension of the knee joint and complete lack of plantar flexion of the ankle joint are common symptoms of stroke. This thesis encompasses the simulation of hemiparetic function using both a knee orthosis with variable impedance, specifically in terms of stiffness and damping, and the Proprioception Interference Apparatus.

The section regarding the knee orthosis with variable impedance focuses on the creation and implementation of a small, lightweight, and adjustable orthotic device to be positioned around the knee …

Electrochemical Methods To Characterize Drilled Shaft Deficiencies, Sarah Jo Mobley

USF Tampa Graduate Theses and Dissertations

In recent years drilled shafts have become the preferred foundation method for marine bridges. Typically, the drilled shaft is selected over traditional driven piles due to soil strata encountered, construction economy, increased lateral stiffness requirements, and/or vibration control considerations. The most critical component in drilled shaft construction is borehole stabilization. Wall sloughing or groundwater inclusion can have devastating effects on the strength of the finished shaft however recent research has shown that the materials, more specifically the slurry, used to accomplish stabilization may be having a negative impact on the durability of the finished product. This thesis investigates the durability …

Opportunities To Mainstream Gender In Water And Wastewater Infrastructure Projects: A Case Study In Barbados, Wainella Isaacs

USF Tampa Graduate Theses and Dissertations

According to the World Resources Institute, Barbados is one of seven Caribbean countries ranked as being the most water stressed territories in the world. Prevailing drought conditions for the period 2010-2016 further compromised its water security while confirming predictions of a drier regional Caribbean climate. The simultaneous failing of at least 50-year-old water infrastructure at many points in the distribution network adds to these water stress conditions, and presents a financial burden to the local water utility in the form of lost revenues, and increased energy consumption for pumping.

Climate change and its impacts are not gender-neutral, and water infrastructure …

Optimal Bidding Strategy For A Strategic Power Producer Using Mixed Integer Programming, Sayed Abdullah Sadat

USF Tampa Graduate Theses and Dissertations

The thesis focuses on a mixed integer linear programming (MILP) formulation for a bi-level mathematical program with equilibrium constraints (MPEC) considering chance constraints. The particular MPEC problem relates to a power producer’s bidding strategy: maximize its total benefit through determining bidding price and bidding power output while considering an electricity pool’s operation and guessing the rival producer’s bidding price. The entire decision-making process can be described by a bi-level optimization problem. The contribution of our thesis is the MILP formulation of this problem considering the use of chance constrained mathematical program for handling the uncertainties.

First, the lower-level poor operation …

Engineered Nanocomposite Materials For Microwave/Millimeter-Wave Applications Of Fused Deposition Modeling, Juan De Dios Castro

USF Tampa Graduate Theses and Dissertations

A variety of high-permittivity (high-k) and low-loss ceramic-thermoplastic composite materials as fused deposition modeling (FDM) feedstock, based on cyclo-olefin polymer (COP) embedded with sintered ceramic fillers, have been developed and investigated for direct digital manufacturing (DDM) of microwave components. The composites presented in this dissertation use a high-temperature sintering process up to 1500°C to further enhance the dielectric properties of the ceramic fillers. The electromagnetic (EM) properties of these newly developed FDM composites were characterized up to the Ku-band by using the cavity perturbation technique. Several models for prediction of the effective relative dielectric permittivity of composites based …

Recombinant Elastin Based Nanoparticles For Targeted Gene Therapy, Dagmara Anne Monfort

USF Tampa Graduate Theses and Dissertations

Gene therapy is a technique used to inactivate, replace or insert a corrective copy of a defective gene in order to help diseased tissues to function properly. Gene therapy is a promising treatment for many diseases cancer, cystic fibrosis, and Parkinson’s. There are different methods to introduce a gene to the cell; one of them is the use of viruses. Among viruses, lentiviruses have been popular vectors for gene delivery due to their efficient mode of gene delivery. However, the non-specific delivery of genes associated with viruses may result in undesirable side effects. Here, we propose a heterogeneous nanoparticle delivery …

Impact Force Reduction Using Variable Stiffness With An Optimal Approach For Jumping Robots, Juan Manuel Calderon Chavez

USF Tampa Graduate Theses and Dissertations

Running, jumping and walking are physical activities that are performed by humans in a simple and efficient way. However, these types of movements are difficult to perform by humanoid robots. Humans perform these activities without difficulty thanks to their ability to absorb the ground impact force. The absorption of the impact force is based on the human ability to vary muscles stiffness.

The principal objective of this dissertation is to study vertical jumps in order to reduce the impact force in the landing phase of the jump motion of humanoid robots. Additionally, the impact force reduction is applied to an …

Impedance Optimized Electric Pulses For Enhancing Cutaneous Gene Electrotransfer, Reginald Morley Atkins

USF Tampa Graduate Theses and Dissertations

Electric field mediated gene delivery modalities have preferable safety profiles with the ability to rapidly transfect cells in vitro and in vivo with high efficiency. However, the current state of the art has relied on trial and error studies that target the average cell within a population present in treated tissue to derive electric pulse parameters. This results in fixed gene electrotransfer (GET) parameters that are not universally optimum. Slow progress towards the validation of a mechanism that explains this phenomena has also hindered its advancement in the clinic. To date, GET methods utilizing feedback control as a means to …

Catalytic Upgrading Of Biogas To Fuels: Role Of Reforming Temperature, Oxidation Feeds, And Contaminants, Nada Elsayed

USF Tampa Graduate Theses and Dissertations

Global energy demands are constantly increasing and fossil fuels are a finite resource. The shift towards alternative, more renewable and sustainable fuels is inevitable. Furthermore, the increased emissions of greenhouse gases have forced a pressing need to find cleaner, more environmentally friendly sources of fuel. Biomass energy is a promising alternative fuel because it offers several important advantages. It is a renewable energy form, it comes from many sources and produces biogas (CH₄ and CO₂). Furthermore, it can have a zero carbon footprint; this is due to the fact that the carbon produced is from the same …

Improved 2d And 3d Resistivity Surveys Using Buried Electrodes And Optimized Arrays: The Multi-Electrode Resistivity Implant Technique (Merit), Henok Gidey Kiflu

USF Tampa Graduate Theses and Dissertations

This thesis presents a novel resistivity method called Multi-Electrode resistivity technique (MERIT) that is used for high resolution imaging of complex geologic features at depth and near the edges of survey lines. The MERIT electrodes are especially shaped and designed to be self-driven using a robust-direct push technique. Measurements are taken using optimized arrays that are generated using a modified version of the “Compare-R” optimization algorithm. This work focused on both two-dimensional (MERIT2D) and three-dimensional (MERIT3D) applications of the buried array and show the relevance of the additional information gained by the addition of deep electrodes especially in sites with …

Photocatalytic Reduction Of Co2 With Tunable Bandgap And Bandedge Materials, Thuhuong T. Ngo

USF Tampa Graduate Theses and Dissertations

Solar energy is a sustainable resource which has substantial potential to meet the increasing demand for renewable energy. Though there has been some success in harvesting solar energy for electricity production, converting solar energy to chemical energy as fuels is still a challenge due to low efficiency.

Since the discovery of TiO₂ photocatalysts for splitting water (4) and reducing CO₂ (5) to form useful chemical feedstock such as H₂, CO and CH₄, much research has been done to increase the efficiency of photocatalysts. However, the current conversion efficiency of photocatalysts remains low (~5%) (6, …