Engineering Commons^™

The Soft Mode Driven Dynamics Of Ferroelectric Perovskites At The Nanoscale: An Atomistic Study, Kevin Mccash

USF Tampa Graduate Theses and Dissertations

The discovery of ferroelectricity at the nanoscale has incited a lot of interest in perovskite ferroelectrics not only for their potential in device application but also for their potential to expand fundamental understanding of complex phenomena at very small size scales. Unfortunately, not much is known about the dynamics of ferroelectrics at this scale. Many of the widely held theories for ferroelectric materials are based on bulk dynamics which break down when applied to smaller scales. In an effort to increase understanding of nanoscale ferroelectric materials we use atomistic resolution computational simulations to investigate the dynamics of polar perovskites. Within …

An Evaluation Of The Use Of Composting Latrines And The Perceptions Of Excrement In Ngäbe Communities In Panama, Patricia Anna Marie Wilbur

USF Tampa Graduate Theses and Dissertations

Engineers are exploring a new paradigm in wastewater treatment; focus is shifting to the recovery and reuse of energy, water, and nutrients. Ecological sanitation (EcoSan) technologies, which allow for this recovery and reuse, are an environmentally sound option for the future of sanitation. While the technology to achieve this goal of recovery and reuse exists, a limiting factor is user attitudes and perceptions. Social sciences, especially anthropology, can and should inform engineering projects to ensure socio-cultural sustainability.

Since 2003, rural indigenous Ngäbe communities in Panama have been implementing ecological sanitation projects, mainly double vault urine diverting (DVUD) latrines known as …

Multilayer Nanomagnetic Systems For Information Processing, Srinath Rajaram

USF Tampa Graduate Theses and Dissertations

The Spin-Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) has opened new doors as an emerging technology with high potential to replace traditional CMOS-based memory technology. This has come true due to the density, speed and non- volatility that have been demonstrated. The STT-MRAM uses Magnetic Tunnel Junction (MTJ) elements as non-volatile memory storage devices because of the recent discovery of spin-torque phenomenon for switching the magnetization states. The magnetization of the free layer in STT-MRAM can be switched from logic "1" to logic "0" by the use of a spin-transfer torque. However, the STT-MRAMs have till now only been used …

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 …

Assessing The Impacts Of Unrestricted Pesticide Use In Small-Scale Agriculture On Water Quality And Associated Human Health And Ecological Implications In An Indigenous Village In Rural Panam[Aacute], Sarah Louise Watson

USF Tampa Graduate Theses and Dissertations

In 2014, the global pesticide industry's projected worth is $52 billion and by 2020, the developing world will make up one-third of the world's chemical production and consumption. Pesticides can have unintended negative consequences for human health and the environment, especially in the developing world where regulations are loose or nonexistent. One country with unrestricted use of pesticides is Panam[aacute], especially in Santa Rosa de Cucunatí. In this indigenous village, small-scale farmers and ranchers spray paraquat, glyphosate, picloram, and 2,4-D at higher elevations than the spring water source of a gravity-fed water system, the river, and the village. The objective …

Asymmetric Unilateral Transfemoral Prosthetic Simulator, Tyagi Ramakrishnan

USF Tampa Graduate Theses and Dissertations

amputation, which includes reduced force generation at the knee and ankle, reduced control of the leg, and different mass properties relative to their intact leg. The physical change in the prosthetic leg leads to gait asymmetries that include spatial, temporal, or force differences. This altered gait can lead to an increase in energy consumption and pain due to compensating forces and torques. The asymmetric prosthesis demonstrated in this research aims to find a balance between the different types of asymmetries to provide a gait that is more symmetric and to make it overall easier for an amputee to walk.

Previous …

Drinking Water In The Developing World: Sources Of Fecal Contamination In Pitcher Pump Systems And Measurement Alternatives, Meghan Wahlstrom

USF Tampa Graduate Theses and Dissertations

It has been reported that globally we have achieved Millennium Development Goal (MDG) Target 7C, to halve the proportion of the population without access to safe drinking water; however, there is a major flaw with this statement. While Target 7C calls for access to `safe' drinking water, what is actually being measured and reported is access to an `improved' water source. The World Health Organization (WHO) maintains that they must use this proxy measure because the methods for water quality testing are too expensive and logistically complicated, but by doing so, they may be over reporting safe water coverage.

This …

Selected Topics In Foundation Design, Quality Assurance, And Remediation, Danny Winters

USF Tampa Graduate Theses and Dissertations

There are over 602,000 bridges in the United States, of which 12.5% are classified as functionally obsolete and 11.2% are structurally deficient. The functionally obsolete bridges will require expansion or replacement to increase the service capacity of the bridge. The structurally deficient bridges will either need remediation of the load carrying elements which are damaged or deteriorated or will need to be replaced completely. Replacement of the bridges means new construction; new construction means better design and quality assurance to meet the 100+ year service life requirement in place now. Rehabilitation of bridges will require better design and quality assurance …

Nanodiamond Based Composite Structures For Biosensing Applications, Pedro Javier Villalba

USF Tampa Graduate Theses and Dissertations

This dissertation presents the synthesis and application of nanodiamond based materials for electrochemical biosensors. In this research work, nanodiamond particles have been used to prepare doped and undoped nanocrystalline diamond films, and conducting polymer composites for enhanced biosensing. The performance of the synthetized materials towards sensing applications was evaluated against glucose amperometric biosensing. Besides, cholesterol biosensing was attempted to prove the capabilities of the platform as a generic biosensing substrate.

Biosensors have been proved to provide reliable detection and quantification of biological compounds. The detection of biological markers plays a key factor in the diagnosis of many diseases and, even …

Investigation Of Energy Alignment Models At Polymer Interfaces, Wenfeng Wang

USF Tampa Graduate Theses and Dissertations

The presented study investigated the Induced Density of Interface States (IDIS) model at different polymer interfaces by using photoemission spectroscopy in combination with electrospray deposition.

In recent years, organic electronics have attracted considerable attention due to their advantages of low-cost and easy-fabrication. The performance of such devices crucially depends on the energy barrier that controls the interface charge transfer. A significant effort has been made to explore the mechanisms that determine the direction and magnitude of charge transfer barriers in these devices. As a result of this effort, the IDIS model was developed to predict the energy alignment at metal/organic …

A System Dynamics Approach To Integrated Water And Energy Resources Management, Yilin Zhuang

USF Tampa Graduate Theses and Dissertations

Water and energy are two of the most important resources for societal prosperity and economic development. It is clear that water and energy are intrinsically linked together and depend on one another in modern society. To date, however, efforts on water-energy nexus concentrate on quantifying the energy use in water cycle or the water use in energy production. From management perspective, water and energy are still managed separately. Little work has been done to investigate the impacts of the management options associated with one resource on the other and examine the integrated water and energy management options. Accordingly, the overall …

Homochiral Metal-Organic Materials: Design, Synthetic And Enantioseletive Separation, Shi-Yuan Zhang

USF Tampa Graduate Theses and Dissertations

Owing to the growing demand for enantiopurity in biological and chemical processes, tremendous efforts have been devoted to the synthesis of homochiral metal-organic materials (MOMs) because of their potential applications in chiral separation and asymmetric catalysis. In this dissertation, the synthetic strategies for homochiral MOMs are discussed keeping the focus on their applications. Two distinct approaches have been taken to synthesize chiral structures with different topologies and accessible cavities. The chiral MOMs have been utilized in enantioselective separation of racemates.

Chiral variants of the prototypal metal-organic framework MOF-5, δ-CMOF-5 and [lambda]-CMOF-5, have been synthesized by preparing MOF-5 in the presence …

Numerical Simulation Of Flow In Ozonation Process, Jie Zhang

USF Tampa Graduate Theses and Dissertations

In the last two decades, Computational Fluid Dynamics (CFD) has shown great potential as a powerful and cost-efficient tool to troubleshoot existing disinfection contactors and improve future designs for the water and wastewater treatment utilities.

In the first part of this dissertation two CFD simulation methodologies or strategies for computing turbulent flow are evaluated in terms of the predicted hydraulic performance of contactors. In the LES (large eddy simulation) methodology, the more energetic, larger scales of the turbulence are explicitly computed or resolved by the grid. In the less computationally intensive RANS (Reynolds-averaged Navier-Stokes) methodology, only the mean component of …

An Assessment Of The Emas Pump And Its Potential For Use In Household Water Systems In Uganda, Jacob Daniel Carpenter

USF Tampa Graduate Theses and Dissertations

Rural improved water supply coverage in Uganda has stagnated around 64% for a number of years and at this point more than 10 million rural people do not have access to an improved drinking water source. It has been recognized that progress toward improved water supply coverage and increased service levels may be gained through Government and nongovernmental organization (NGO) support of private investment in household and shared water supplies, commonly known as Self-supply. Self-supply can be promoted by introducing and building local capacity in appropriate and affordable water supply technologies such as hand-dug wells, manually drilled boreholes, low-cost pumps, …

Impedance Extraction By Matlab/Simulink And Labview/Multisim, Jen-Pin Lin

USF Tampa Graduate Theses and Dissertations

This thesis studies the techniques of small-signal impedance measurement in three-phase power systems. Stability issue has become critically important since power electronics are highly applied in power distribution and conversion systems. Controlled output systems cause the risk of instability. In order to obtain the impedance model, an impedance extraction in D-Q reference frame algorithm is developed. This paper also applied Interpolated Fast Fourier Transform to increase accuracy of impedance model. Based on the voltage injection, Phase-Locked Loop, Park Transform, D-Q reference frame, and IPFFT. Three-phase system has been realigned on D-Q coordinate and impedance model is extracted in this form. …

A 3-D Pseudo-Rigid-Body Model For Rectangular Cantilever Beams With An Arbitrary Force End-Load, Jairo Renato Chimento

USF Tampa Graduate Theses and Dissertations

This dissertation introduces a novel three-dimensional pseudo-rigid-body model (3-D PRBM) for straight cantilever beams with rectangular cross sections. The model is capable of capturing the behavior of the neutral axis of a beam loaded with an arbitrary force end-load. Numerical integration of a system of differential equations yields approximate displacement and orientation of the beam's neutral axis at the free end, and curvatures of the neutral axis at the fixed end. This data was used to develop the 3-D PRBM which consists of two torsional springs connecting two rigid links for a total of 2 degrees of freedom (DOF). The …

A Multi-Case Study Of Student Interactions With Educational Robots And Impact On Science, Technology, Engineering, And Math (Stem) Learning And Attitudes, Stephanie Holmquist

USF Tampa Graduate Theses and Dissertations

The demand for STEM trained workers continues to increase not only in the United States, but globally. Reports have indicated that the United States is not doing a good job encouraging students to pursue STEM oriented degrees. In particular, it has become increasingly important to emphasize STEM connections at an early level in order to encourage student career exploration as they continue their education. Educational robots represent a unique alternative to traditional methods, especially at the elementary level. Considering the use of educational robots have largely been ignored at this level, the purpose of this study was to describe the …

Neural Correlates Of Spectral, Temporal And Spectro-Temporal Modulation, Anusha Mohan

USF Tampa Graduate Theses and Dissertations

Natural sounds are characterized by the distribution of acoustic power over different frequency regions and/or time. This is termed spectral, temporal or spectro-temporal modulation. The auditory system is equipped with banks of filters tuned to different spectral, temporal and spectro-temporal modulation frequencies (SM, TM, STM). The sensitivity of the peripheral system to these modulations can be measured by undertaking a linear systems approach. In addition to understanding the psychophysical sensitivity, studying the neural patterns of their processing is also critical. The current study is an attempt to understand the relationship between the behavioral and neural correlates of spectral, temporal and …

Statistical And Prognostic Modeling Of Clinical Outcomes With Complex Physiologic Data, Monica A. Puertas

USF Tampa Graduate Theses and Dissertations

Laboratory tests are a primary resource for diagnosing patient diseases. However, physicians often make decisions based on a single laboratory result and have a limited perspective of the role of commonly-measured parameters in enhancing the diagnostic process. By providing a dynamic patient profile, the diagnosis could be more accurate and timely, allowing physicians to anticipate changes in the recovery trajectory and intervene more effectively.

The assessment and monitoring of the circulatory system is essential for patients in intensive care units (ICU). One component of this system is the platelet count, which is used in assessing blood clotting. However, platelet counts …

Lead (Pb) Contamination Of Water Drawn From Pitcher Pumps In Eastern Madagascar, David Bradlee Akers

USF Tampa Graduate Theses and Dissertations

Access to safe water supply--a major determinant of public health--is less than 50% in Madagascar, and access to piped, treated water remains out of reach financially for many in the urban and peri-urban areas where available. The Self-supply option of the Pitcher Pump has been meeting the need for household water in coastal areas of Madagascar since the early 1960s and has proven a sustainable option for many. These pumps make use of leaded components in the construction, however, which may pose a health risk for heavy metal intoxication and therefore cause the water to be unsafe for drinking and …

Sustainable Energy And Nutrient Recovery From Swine Waste, Adib Amini

USF Tampa Graduate Theses and Dissertations

Swine production represents approximately 40% of the world's meat production, and swine wastes contain high concentrations of organic matter, nitrogen (N) and phosphorus (P). Swine production is intensifying as meat demand increases and concentrated animal feeding operations (CAFOs) are becoming increasingly common, making it difficult to treat the waste generated. A system for holistic treatment of swine waste produced in CAFOs was investigated in this study that sustainably generates energy and recovers N and P as saleable fertilizers. The system uses anaerobic digestion (AD) for methane production and solids stabilization, followed by precipitation of struvite (MgNH4PO4*6H2O) and recovery of N …

Antiviral Resistance And Dynamic Treatment And Chemoprophylaxis Of Pandemic Influenza, Sandro Paz

USF Tampa Graduate Theses and Dissertations

Public health data show the tremendous economic and societal impact of pandemic influenza in the past. Currently, the welfare of society is threatened by the lack of planning to ensure an adequate response to a pandemic. This preparation is difficult because the characteristics of the virus that would cause the pandemic are unknown, but primarily because the response requires tools to support decision-making based on scientific methods. The response to the next pandemic influenza will likely include extensive use of antiviral drugs, which will create an unprecedented selective pressure for the emergence of antiviral resistant strains. Nevertheless, the literature has …

Evaluation Of Hand Augered Well Technologies' Capacity To Improve Access To Water In Coastal Ng[Oumlaut]Be Communities In Panama, Sarah Hayman

USF Tampa Graduate Theses and Dissertations

Amid the global efforts surrounding United Nations' Millennium Development Goal Target 7c to improve access to safe and sustainable drinking water among populations who lack this resource, it has become essential to monitor and evaluate progress. Development initiatives working to achieve improved drinking water access often introduce appropriate technologies designed to be sustainably owned and operated by populations in rural areas suffering from water related hardships. It is valuable to thoroughly examine the degree to which these technologies satisfy intended objectives and affect user experienced water access. The accurate reflection of impact and progress can be complex, as the evaluation …

Soil Remediation Using Solvent Extraction With Hydrodehalogenation And Hydrogenation In A Semicontinuous System, Robert John Panczer

USF Tampa Graduate Theses and Dissertations

The objective of this thesis is to aid in the development of Remedial Extraction And Catalytic Hydrodehalogenation (REACH), a green remediation technology used to remove and destroy halogenated hydrophobic organic compounds from soil. REACH has no secondary waste streams, uses an environmentally benign solvent, and aims to catalytically destroy rather than transfer the organic contaminants into a different phase. In this thesis, a bench-top semicontinuous model of the proposed remediation technology was constructed and used to extract the model contaminant, 1,2,4,5-tetrachlorobenzene, from soil and to convert it to an acceptable end product, cyclohexane. Palladium was used as a catalyst for …

Design, Simulation, Prototype, And Testing Of A Notched Blade Energy Generation System, Henry Cabra

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the design, simulation, prototype, and test of a new energy generation system, which transforms rotational motion into electricity by the use of an innovative turbine-generator. The system is divided in two assembled subsystems that interact to finally transform kinetic energy into electricity. The first subsystem is a miniaturized notched impulse turbine system, and the second one is a millimeter permanent magnet generator (PMG) assembled into the turbine.

The conversion of biomechanical energy to electric energy, using clean and free energy produced by a living organism, is being increasingly researched [1]-[11]. These are all viable options, but advantages …

Sic For Advanced Biological Applications, Joseph Register

USF Tampa Graduate Theses and Dissertations

Silicon carbide (SiC) has been used for centuries as an industrial abrasive and has been

actively researched since the 1960's as a robust material for power electronic applications.

Despite being the first semiconductor to emit blue light in 1907, it has only recently been

discovered that the material has crucial properties ideal for long-term, implantable biomedical

devices. This is due to the fact that the material offers superior biocompatibility and

hemocompatibility while providing rigid mechanical and chemical stability. In addition, the material

is a wide-bandgap semiconductor that can be used for optoelectronics, light delivery, and optical

sensors, which is the …

Combined Metal-Enhanced Fluorescence-Surface Acoustic Wave (Mef-Saw) Biosensor, Samuel Morrill

USF Tampa Graduate Theses and Dissertations

Immunofluorescence assays are capable of both detecting the amount of a protein and the location of the protein within a cell or tissue section. Unfortunately, the traditional technique is not capable of detecting concentrations on the nanoscale. Also, the technique suffers from non-specific attachment, which can cause false-positives, as well as photobleaching when detecting lower concentrations is attempted. There is also a time constraint problem since the technique can take from many hours to a few days in some cases.

In this work, metal-enhanced fluorescence (MEF) is used to lower the detection limit and reduce photobleaching. Unfortunately, MEF also increases …

Investigation Of Tio2 And Invo4-Tio2 Semiconductors For The Photocatalytic Degradation Of Aqueous Organics, Sandra L. Pettit

USF Tampa Graduate Theses and Dissertations

Water is a vital natural resource. To develop more sustainable water systems, we must focus efforts on the removal of persistent contaminants. Aqueous organic contaminants include azo dyes, halogenated organics (e.g. pesticides), and algal and bacterial metabolites. The latter are common to surface waters and freshwater aquaculture systems and can cause taste and odor problems. Two of the principal organoleptic compounds are geosmin and 2-methylisoborneol (MIB). Traditional oxidation treatment methods, utilizing chlorine, hydrogen peroxide, and potassium permanganate, have been employed with varying levels of efficacy for removal of these and other organic contaminants. Advanced Oxidation Processes (AOPs) have greater potential …

[M3(Μ3-O)(O2cr)6] And Related Trigonal Prisms: Versatile Molecular Building Blocks For 2-Step Crystal Engineering Of Functional Metal-Organic Materials, Alexander Schoedel

USF Tampa Graduate Theses and Dissertations

Metal-organic materials (MOMs) assembled from metal-based building blocks and organic linkers have attracted much interest due to their large pore dimensions and their enormous structural diversity. In comparison to their inorganic counterparts (zeolites), these crystalline materials can be easily modified to tailor pore dimensions and functionality for specifically targeted properties.

The work presented herein encompasses the development of a synthetic 2-step process for the construction of novel families of MOMs or 'platforms' and allow us exquisite design and control over the resulting network topologies. Examples of cationic mesoporous structures were initially exploited, containing carboxylate based centers connected by metal-pyridine bonds. …

A Recreation And Ballistic Evaluation Of Otto Schneeloch's Firearm Curiosity - The .307 Triangular, Amber Nicole Shukitis

USF Tampa Graduate Theses and Dissertations

Otto Scheeloch's U.S. Patent No. 134,442 of 1872 describes a unique firearm that uses triangular bullets. The current research effort evaluates the ballistic performance of Otto's disclosure for the very first time. To achieve this goal it was necessary to seek out surviving artifacts and scour the historical record in search of all the parameters needed to meticulously recreate the curious triangular cartridges and the corresponding gun barrel, with its matching twisted triangular bore. Every aspect of the resulting reproduction ammunition was made to be as authentic as possible, including the use of vintage civil war era bullet lead, bullet …