Engineering Commons^™

Supercritical Fluid Aided Microencapsulation Of Dry Powders, Raquel Carvallo

USF Tampa Graduate Theses and Dissertations

Coating of fine particles to produce tailored surface properties is currently a key development for supercritical fluids applications, in different areas such as: pharmaceutical, nutraceutical, cosmetic, agrochemical, electronic and specialty chemistry industries. During the encapsulation process the particles surface can be designed with specific properties by spreading a thin film coating material over the surface of the particles.

Chitosan, a natural polymer, was used in this work as the encapsulant material. Chitosan is biocompatible, biodegradable to normal body constituents, safe, non-toxic, bacteriostatic, anticancerogen, and versatile polymer. These attributes are among the properties that make Chitosan an attractive component of pharmaceutical …

Modeling Roadside Safety Hazards To Predict Annual Crash Cost To Encroaching Vehicles In Rural Road Networks, Isidro Delgado

USF Tampa Graduate Theses and Dissertations

Roadside crashes account for a large portion of total fatal crashes that occur annually in the United States. About 30% of those fatalities are the result of single vehicle run-off-road crashes. A large proportion of these fatal crashes occur in rural roads when vehicles depart from the travel lane and collide with trees or other roadside safety hazards. Many of these run-off-road accidents occur in local roads that carry traffic volumes between 1,000 and 20,000 vehicles per day. Many of these roads are part of the jurisdiction of county authorities faced with the dilemma of having too many "potentially dangerous" …

Anaerobic Membrane Bioreactor (Anmbr) For Treatment Of Landfill Leachate And Removal Of Micropollutants, Anh Tien Do

USF Tampa Graduate Theses and Dissertations

To date, most studies on the fate and removal of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCPs) in wastewater focus on their fate in municipal wastewater treatment plants, and mostly under aerobic condition. There are limited studies related to anaerobic condition and (to our knowledge) no study on the removal of EDCs in landfill leachate by AnMBR. Moreover, for most studies under anaerobic condition, the removal of EDCs was only reported in the liquid phase; solid phase extraction was not reported, thereby preventing mass balance in the studies.

This research was conducted to investigate the potential …

Apparent Total Evaporative Resistance Values From Human Trials Over A Range Of Metabolic And Heat Stress Levels, Matthew David Dooris

USF Tampa Graduate Theses and Dissertations

Failure to maintain thermal equilibrium can cause uncontrollable increases in body core temperature beyond critical upper limits. In selecting clothing, consideration must be given to the heat transfer properties of clothing that may restrict the cooling capacity of the human body under heat stress conditions, most importantly, apparent total evaporative resistance (R_e,T,_a). This study calculated and compared R_e,T,_a for five clothing ensembles under varying heat stress conditions, including three relative humidity (RH) levels and three stages of heat stress to determine if R_e,T,_a values varied or remained the same with …

Identification Of Patient Recovery Patterns After Cardiovascular Surgery Based On Laboratory Tests Results, Alcides Ricardo Santander Mercado

USF Tampa Graduate Theses and Dissertations

In this dissertation is proposed a methodology to identify patient's recovery patterns after cardiovascular surgery based on laboratory tests results. The main purpose is to enhance the understanding of the manifestations of postsurgical complications in patients who underwent cardiovascular surgery. The analysis of patients' recovery process is based on the relationship between plasma calcium, ionized calcium and platelet count over time.

Laboratory results from the James A. Haley Veterans' Hospital databases, related to patients admitted to the Surgical Intensive Care Unit (SICU) after cardiac surgery (coronary artery bypass, aortic value replacement and mitral valve replacement), are used. These databases contain …

Atrial Fibrillation Signal Analysis, Raja Sarath Chandra Prasad Vaizurs

USF Tampa Graduate Theses and Dissertations

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia encountered in clinical practice and is associated with an increased mortality and morbidity. Identification of the sources of AF has been a goal of researchers for over 20 years. Current treatment procedures such as Cardio version, Radio Frequency Ablation, and multiple drugs have reduced the incidence of AF. Nevertheless, the success rate of these treatments is only 35-40% of the AF patients as they have limited effect in maintaining the patient in normal sinus rhythm. The problem stems from the fact that there are no methods developed to analyze …

Modeling And Control Of Wind Generation And Its Hvdc Delivery System, Haiping Yin

USF Tampa Graduate Theses and Dissertations

As the most developed renewable energy source, wind energy attracts the most research attentions. Wind energy is easily captured far away from the places where wind energy is used. Because of this unique characteristic of the wind, the generation and delivery systems of the wind energy need to be well controlled. The objective of this dissertation work is modeling and control of wind generation and its High Voltage Direct-Current (HVDC) delivery system.

First of all, modeling of the Doubly-fed Induction Generator (DFIG)-based wind farm is presented including dynamic models of the wind turbine, shaft system and DFIG. Detailed models of …

Robotic Hand Evaluation Based On Task Specific Kinematic Requirements, Carlos Rafael Neninger

USF Tampa Graduate Theses and Dissertations

With the rise autonomous and robotic systems in field applications, the need for dexterous, highly adaptable end effectors has become a major research topic. Control mechanisms of robotics hands with a high number independent actuators is recognized as a complex, high dimensional problem, with exponentially complex algorithms. However, recent studies have shown that human hand motion possesses very high joint correlation which translates into a set of predefined postures, or synergies. The hand produces a motion using a complementing contribution of multiple joints, called synergies. The similarities place variables onto a common dimensional space, effectively reducing the number of independent …

Fabrication And Characterization Of Electrospun Cactus Mucilage Nanofibers, Yanay Pais

USF Tampa Graduate Theses and Dissertations

This work seeks to fabricate, optimize, and characterize nanofibers of cactus Opuntia ficus-indica mucilage and Poly (vinyl alcohol) (PVA) by electrospinning. Mucilage is a neutral mixture of sugars produced by cactus and PVA is a non-toxic, water-soluble, synthetic polymer, which is widely used as a co-spinning agent for polymers. Mucilage was extracted from the cactus pad and prepared for electrospinning by mixing with acetic acid. Two types of PVA were used differentiating in high and low molecular weights. Concentrations of PVA were varied to find an adequate threshold for fiber formation. Changing the ratio of PVA to cactus mucilage produced …

Molybdenum Nitride Films In The Back Contact Structure Of Flexible Substrate Cdte Solar Cells, Vasudha Guntur

USF Tampa Graduate Theses and Dissertations

CdTe solar cells in the superstrate configuration have achieved record efficiencies of 16% but those in the substrate configuration have reached efficiencies of only 7.8%. A major reason for the lower efficiency of substrate CdTe solar cells is the poor back contact. In this work, CdTe solar cells of the substrate configuration have been fabricated on flexible metallic substrates. For this type of devices, impurity diffusion out of stainless-steel substrates due to high temperature processing can be a cause for poor cell performance. It is necessary to investigate ways of improving the back contact by trying to mitigate the above …

An Ofdm Based Aeronautical Communication System, Jamal Haque

USF Tampa Graduate Theses and Dissertations

Wireless connectivity is becoming an integral part of our society. A new paradigm for aeronautical data services is beginning to take shape. The advances in signal processing, rapid prototyping, an insatiable consumer demand for Internet services, increase in aircraft traffic, aircraft safety, etc., are driving the demand for high speed data services. Programs led by the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), EUROCONTROL and Networking the Sky for Civil Aeronautical Communications (NEWSKY) are all looking into aeronautical platforms as part of their Aeronautical Data Network (ADN). The desire is to provide low delay, cost effective …

Fabrication And Characterization Of Novel 2sss Cigs Thin Film Solar Cells For Large-Scale Manufacturing, Keshavanand Jayadevan

USF Tampa Graduate Theses and Dissertations

A novel 2SSS (2 Step Solid Selenization) CIGS (Cu, In, Ga, Se) thin film solar cell recipe was developed which can be a replacement to the conventional co-deposition process usually employed for large-scale manufacturing. The co-deposition procedure is faced with multiple problems such as selenium incorporation, effective gallium incorporation in the absorber. It is a 2-step proprietary procedure with better control over growth mechanisms and material utilization for the absorber layer for the CIGS thin film solar cells. It makes use of solid selenium source as preferred by manufacturers. Each step of the 2-step procedure was dealt with separately for …

Decision Support Models For Design Of Fortified Distribution Networks, Qingwei Li

USF Tampa Graduate Theses and Dissertations

Lean distribution networks have been facing an increased exposure to the risk of unpredicted disruptions causing significant economic forfeitures. At the same time, the existing literature contains very few studies that examine the impact of fortification of facilities for improving network reliability. This dissertation presents three related classes of models that support the design of reliable distribution networks. The models extend the uncapacitated P-median and fixed-charge location models by considering heterogeneous facility failure probabilities, supplier backups, and facility fortification within a finite budget. The first class of models considers binary fortification via linear fortification functions. The second class of models …

Resource Allocation Methodologies With Fractional Reuse Partitioning In Cellular Networks, Hazar Aki

USF Tampa Graduate Theses and Dissertations

Conventional cellular systems have not taken full advantage of fractional frequency reuse and adaptive allocation due to the fixed cluster size and uniformed channel assignment procedures. This problem may cause more fatal consequences considering the cutting-edge 4G standards which have higher data rate requirements such as 3GPP-LTE and IEEE 802.16m (WiMAX). In this thesis, three different partitioning schemes for adaptive clustering with fractional frequency reuse were proposed and investigated. An overlaid cellular clustering scheme which uses adaptive fractional frequency reuse factors would provide a better end-user experience by exploiting the high level of signal to interference ratio (SIR). The proposed …

The Impact Of Pharmacy Work Design On Pharmacist Productivity, Nicholas Allen Coblio

USF Tampa Graduate Theses and Dissertations

Healthcare costs in the United States continue to grow at an alarming rate. Concerning the cost of medications, there are a number of factors that drive these costs. While personnel costs are not the largest of these, they do contribute a significant portion. The cost of the cognitive component of order processing by pharmacists can range from three dollars to over six dollars per prescription depending on the production throughput of the pharmacist.

Studies at the organization which was the focus of the research, as well as reports in the literature, indicated that work disruption and other environmental factors could …

Analytical Methods To Support Risk Identification And Analysis In Healthcare Systems, Laila Nadime Cure Vellojin

USF Tampa Graduate Theses and Dissertations

Healthcare systems require continuous monitoring of risk to prevent adverse events. Risk analysis is a time consuming activity that depends on the background of analysts and available data. Patient safety data is often incomplete and biased. This research proposes systematic approaches to monitor risk in healthcare using available patient safety data. The methodologies combine traditional healthcare risk analysis methods with safety theory concepts, in an innovative manner, to allocate available evidence to potential risk sources throughout the system. We propose the use of data mining to analyze near-miss reports and guide the identification of risk sources. In addition, we propose …

Techniques For Enhancing Reliability In Vlsi Circuits, Ransford Morel Hyman Jr

USF Tampa Graduate Theses and Dissertations

Reliability is an important issue in very large scale integration(VLSI) circuits. In the absence of a focus on reliability in the design process, a circuit’s functionality can be compromised. Since chips are fabricated in bulk, if reliability issues are diagnosed during the manufacturing of the design, the faulty chips must be tossed, which reduces product yield and increases cost. Being aware of this situation, chip designers attempt to resolve as many issues dealing with reliability on the front-end of the design phase (architecture or systemlevel modeling) to minimize the cost of errors in the design which increases as the design …

The Impact Of Supply Chain And Network Structure On The Environmental Performance Of Sustainability-Focused Companies, Ozan Ozcan

USF Tampa Graduate Theses and Dissertations

The goal of this dissertation was to contribute to our understanding of the relationship between supply chain structure and the pursuit of a sustainability-driven corporate strategy. The literature indicates that in order to pursue a sustainability-focused strategy, an increased level of integration across the supply chain is required. However, there are also industry-level dynamics that impact observed levels of vertical integration. That is, some industries are naturally more integrated than others based on the maturity level of the industry. Thus, some firms may experience opposing forces regarding their sourcing strategies once they choose to pursue a sustainability-focused strategy.

To explore …

Advances In Fiber Reinforced Polymer Repair Incorporating Cathodic Protection, Julio Ivan Aguilar

USF Tampa Graduate Theses and Dissertations

This dissertation presents findings from two disparate research projects relating to the cathodic protection (CP) of piles supporting bridge elements. The first was a proof of concept study for developing a new hybrid pile repair system incorporating embedded sacrificial zinc anodes within a fiber reinforced polymer (FRP) wrap. The second was to develop and remotely monitor the performance of magnesium anodes protecting steel Hpiles supporting two bridges in Florida.

The hybrid FRP-CP system involved a proof-of-concept laboratory study to refine pressure / vacuum bagging systems for pile repair and to quantify the improvement in the FRP concrete bond. Two different …

Analyses Of Variable Refrigerant Flow And Exergy In Air Conditioning Systems, Rashid Ali Alshatti

USF Tampa Graduate Theses and Dissertations

This thesis consists of two research problems in the air conditioning (A/C) area. For the first problem, the aim is to model and simulate a variable refrigerant flow (VRF) air conditioning system. The coefficient of performance (COP) for refrigeration or heat pump system is one of the critical parameters for designing an air conditioning system. The modeling of the system components for a VRF cycle under different cooling conditions using R-134a and R-22 as refrigerants was carried out. Calculations were performed by varying different parameters such as condenser and evaporator temperatures, and refrigerant type. The R-134a refrigerant shows a better …

Thermal Integrity Profiling Instrumentation Development, Byron Keith Anderson

USF Tampa Graduate Theses and Dissertations

This thesis has shown that the development of the instrumentation necessary to provide in-situ thermal imaging for the determination of homogeneity of concrete is theoretically sound.

Drilled shafts are large diameter underground cast-in-place columns that necessarily rely on sound integrity to properly withstand imposed loadings. As a by-product of the most common construction techniques, the entire process is often completely blind whereby the excavation and concreting processes are conducted beneath the surface of the water table (or slurry level). This results in an inability to inspect the final product and in many cases allows anomalous inclusions (soil cave-ins, slurry pockets, …

Thermo-Mechanical Beam Element For Analyzing Stresses In Functionally Graded Materials, Simon Caraballo

USF Tampa Graduate Theses and Dissertations

Modeling at the structural scale most often requires the use of beam and shell elements. This simplification reduces modeling complexity and computation requirements but sacrifices the accuracy of through-the-thickness information. Several studies have reported various design approaches for analyzing functionally graded material structures. One of these studies proposed a two-node beam element for functionally graded materials (FGMs) based on first order shear deformable (FOSD) theory. The derivation of governing equations included spatial temperature variation. However, only the constant temperature case was carried through in the element formulation. This investigation explore the effects of spatial temperature variation in the axial and …

Mechanistic Modeling Of Photocatalytic Water Disinfection, Omatoyo Kofi Dalrymple

USF Tampa Graduate Theses and Dissertations

The main goal of this research was to develop a mechanism-based model for photocatalytic disinfection of bacteria in water using suspended catalyst pthesiss in batch reactors. The photocatalytic disinfection process occurs as a semiconductor photocatalyst, most commonly titanium dioxide (TiO₂), is irradiated with light of wavelength less than 380 nm to produce hydroxyl radicals and other highly reactive oxidants which can inactivate microorganisms. Photocatalytic disinfection involves a complex interaction of many fundamental mechanisms such as light absorption and scattering by semiconductor pthesiss, electrochemical surface reactions, and heterogeneous colloidal stability. Current models, based largely on chemical reacting systems, do …

Theoretical And Experimental Analysis Of Power And Cooling Cogeneration Utilizing Low Temperature Heat Sources, Gökmen Demirkaya

USF Tampa Graduate Theses and Dissertations

Development of innovative thermodynamic cycles is important for the efficient utilization of low-temperature heat sources such as solar, geothermal, and waste heat sources. Binary mixtures exhibit variable boiling temperatures during the boiling process, which leads to a good thermal match between the heating fluid and working fluid for efficient heat source utilization. This study presents a theoretical and an experimental analysis of a combined power/cooling cycle, which combines the Rankine and absorption refrigeration cycles, uses ammonia-water mixture as the working fluid and produces power and refrigeration, while power is the primary goal. This cycle, also known as the Goswami Cycle, …

Steady And Transient Heat Transfer For Jet Impingement On Patterned Surfaces, Mark Michael Dobbertean

USF Tampa Graduate Theses and Dissertations

Free liquid-jet impingement is well researched due to its high heat transfer ability and ease of implementation. This study considers both the steady state and transient heating of a patterned plate under slot-free-liquid jet impingement. The primary working fluid was water (H2O) and the plate material considered was silicon. Calculations were done for Reynolds number (Re) ranging from 500 to 1000 and indentation depths from 0.000125 to 0.0005 m for three different surface configurations. The effect of using different plate materials and R-134a as the working fluid were explored for the rectangular step case. The distributions of the local and …

Regulation Of Cell Adhesion Strength By Spatial Organization Of Focal Adhesions, Kranthi Kumar Elineni

USF Tampa Graduate Theses and Dissertations

Cell adhesion to extracellular matrix (ECM) is critical to various cellular processes like cell spreading, migration, growth and apoptosis. At the tissue level, cell adhesion is important in the pathological and physiological processes that regulate the tissue morphogenesis. Cell adhesion to the ECM is primarily mediated by the integrin family of receptors. The receptors that are recruited to the surface are reinforced by structural and signaling proteins at the adhesive sites forming focal adhesions that connect the cytoskeleton to further stabilize the adhesions. The functional roles of these focal adhesions extend beyond stabilizing adhesions and transduce mechanical signals at the …

Sequential Anaerobic And Algal Membrane Bioreactor (A2mbr) System For Sustainable Sanitation And Resource Recovery From Domestic Wastewater, Ana Lucia Prieto

USF Tampa Graduate Theses and Dissertations

An innovative wastewater treatment technology was developed to recover renewable resources, such as water, energy and nutrients, from sewage. First, a novel synthetic sewage was evaluated for its suitability to serve as an alternative substrate for lab-scale wastewater treatment (WWT) research. Based on granular dried cat food, Complex Organic Particulate Artificial Sewage (COPAS) is a commercially-available, flexible, and easy to preserve feed. Characteristics of COPAS, namely chemical composition, disintegration/dissolution kinetics, and anaerobic biodegradability, were determined. Anaerobic bioassays indicate that COPAS is highly biodegradable at the concentration used to simulate household sewage (1000 mg/L), with more than 72% of the theoretical …

Biological Effective Dose (Bed) Distribution Matching For Obtaining Brachytherapy Prescription Doses & Dosimetric Optimization For Hybrid Seed Brachytherapy, Jakub Pritz

USF Tampa Graduate Theses and Dissertations

Radioactive seed implant brachytherapy is a common radiotherapy treatment method for prostate cancer. In current clinical practice, a seed consists of a single isotope, such as ¹²⁵I or ¹⁰³Pd. A seed containing a mixture of two isotopes has been proposed for prostate cancer treatment. This study investigates a method for defining a prescription dose for new seed compositions based on matching the biological equivalent dose (BED) of a reference plan.

Ten prostate cancer cases previously treated using single isotope seeds (5 using ¹²⁵I seeds and 5 using ¹⁰³Pd seeds) were selected for this study. Verification of …

Pilot Assessment Of Novel Membrane Bioreactor Processes - Improvements In Biological Nutrient Removal And Membrane Operation, Shaleena Smith

USF Tampa Graduate Theses and Dissertations

With increasing water reuse applications and upcoming stringent regulations for treated wastewater effluent discharge, wastewater plants need to consider alternative technologies beyond conventional treatment processes. The new regulations, Numeric Nutrient Criteria (NNC), may regulate discharge nitrogen and phosphorus concentrations to as low as 0.5 mg/L as N and 10 μg/L as P respectively. To meet these target requirements, system retrofitting to incorporate chemical or advanced nutrient removal systems possibly with membrane technology will most likely be required. Although microfiltration/ultrafiltration membranes coupled with biological processes, otherwise known as membrane bioreactors (MBR), remove contaminants and suspended solids, nutrient removal is minimal to …

Polydimethylsiloxane Mechanical Properties Measured By Macroscopic Compression And Nanoindentation Techniques, Zhixin Wang

USF Tampa Graduate Theses and Dissertations

In this thesis, the relationship between the elastic modulus of PDMS and the base/agent ratio (the amount of crosslinking) is studied. Reliable macroscopic compression test instrument was developed. Preload method was applied for the nanoindentation flat punch test to develop full contact.

In chapter 2, an easy instrument setup for macroscopic compression test is described. A series of PDMS samples with different base/agent ratios were tested using the macroscopic compression method. The relationship between PDMS elastic modulus and its base/agent ratio was established.

In chapter 3, PDMS nanoindentation DMA tests provide stable data with different test control models. The storage …