Engineering Commons^™

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 …

Synthesis, Characterization, And Application Of Molybdenum Oxide Nanomaterials, Michael S. Mccrory

USF Tampa Graduate Theses and Dissertations

Nanostructured molybdenum trioxide (MoO₃) was synthesized and used as a precursor in a comparative study, along with commercial MoO₃, to synthesize molybdenum dioxide (MoO₂) nanoparticles. Scanning electron microscope (SEM) images revealed the particles to be approximately 30-50 nm in diameter. X-ray diffraction (XRD) confirmed MoO₃ was fully reduced to MoO₂ in all cases. Time dependent experiments showed that within two hours no traces of MoO₃ are present. All of the experiments showed the materials were excellent absorbent materials, as well as photocatalysts. Both MoO₂ materials performed almost exactly the same, …

The Control Of Water Contaminants Assisted By Natural Materials, Wen Zhao

USF Tampa Graduate Theses and Dissertations

Natural materials can be used to remove water contaminants by applying proper physical, chemical, and biological water treatment processes. This study involves using natural materials, as they are considered to be more environmentally benign and cost-effective than synthetic materials. This dissertation concentrates on monitoring five major water quality parameters—ammonia, fluoride, turbidity, pH, and fecal indicator bacteria (FIB) —in two major applications where clean water is needed. The focus is on meeting the water quality requirements for each contaminant. The overall objective of this study is to control the levels of ammonia in aquaculture wastewater, and adjust fluoride, turbidity, pH, and …

Rehabilitating Asymmetric Gait Using Asymmetry, Tyagi Ramakrishnan

USF Tampa Graduate Theses and Dissertations

Human gait is a complex process that involves the coordination of the central nervous and muscular systems. A disruption to the either system results in the impairment of a person’s ability to walk. Impairments can be caused by neurological disorders such as stroke and physical conditions like amputation. There is not a standardized method to quantitatively assess the gait asymmetry of affected subjects. The purpose of this research is to understand the fundamental aspects of asymmetrical effects on the human body and improve rehabilitation techniques and devices. This research takes an interdisciplinary approach to address the limitations with current rehabilitation …

Learning To Predict Clinical Outcomes From Soft Tissue Sarcoma Mri, Hamidreza Farhidzadeh

USF Tampa Graduate Theses and Dissertations

Soft Tissue Sarcomas (STS) are among the most dangerous diseases, with a 50% mortality rate in the USA in 2016. Heterogeneous responses to the treatments of the same sub-type of STS as well as intra-tumor heterogeneity make the study of biopsies imprecise. Radiologists make efforts to find non-invasive approaches to gather useful and important information regarding characteristics and behaviors of STS tumors, such as aggressiveness and recurrence. Quantitative image analysis is an approach to integrate information extracted using data science, such as data mining and machine learning with biological an clinical data to assist radiologists in making the best recommendation …

Strong-Dism: A First Attempt To A Dynamically Typed Assembly Language (D-Tal), Ivory Hernandez

USF Tampa Graduate Theses and Dissertations

Dynamically Typed Assembly Language (D-TAL) is not only a lightweight and effective solution to the gap generated by the drop in security produced by the translation of high-level language instructions to low-level language instructions, but it considerably eases up the burden generated by the level of complexity required to implement typed assembly languages statically. Although there are tradeoffs between the static and dynamic approaches, focusing on a dynamic approach leads to simpler, easier to reason about, and more feasible ways to understand deployment of types over monomorphically-typed or untyped intermediate languages. On this occasion, DISM, a simple but powerful and …

Modeling, Simulation And Characterization Of Optoelectronic Properties Of 2d-3d Coo-Ato Nano Structures, Ridita Rahman Khan

USF Tampa Graduate Theses and Dissertations

Devices for converting solar energy to electrical energy are not considerably efficient, though there are abundant renewable solar energy sources. Therefore there is a continuous call for investigation of new devices that are efficient and eco-friendly thereby contributing to harvested energy technology.

This thesis characterizes the optical constant (refractive index) of a novel material, cobalt oxide-antimony doped tin oxide (CoO-ATO). Thin film of CoO-ATO is generated using spin coating of CoO-ATO solution having 76.33% chloroform, 13.47% polystyrene, 10% antimony doped tin oxide and 0.2% cobalt oxide by weight. The thin film is analyzed through ellipsometry to acquire the refractive index …

Water, Sanitation, And Citizenship: Perceptions Of Water Scarcity, Reuse, And Sustainability In Valparaiso De Goias, Brazil, Paola Andrea Gonzalez

USF Tampa Graduate Theses and Dissertations

Access to reliable water and sanitation are two important goals to improve livelihoods around the world. Providing access to improved and safe water resources that are equitable and appropriate to local needs is important to improve sustainability long-term. In addition, framing access to water and sanitation as basic human rights is often used as a rationale in developing new water, sanitation, and hygiene interventions in developing countries around the world. But not all countries consider access to safe water and sanitation as a human right. In the thesis, the politics of improving and investment in water access and sanitation provision …

Analysis Of Distresses In Asphalt Pavement Transitions On Bridge Approaches And Departures, Manvitha Rajalingola

USF Tampa Graduate Theses and Dissertations

Some highway agencies in the United States are experiencing frequent distresses in asphalt pavements on bridge approaches/departures. Commonly observed distresses include alligator cracking and rutting, which reduce roadway smoothness and safety. To lessen the distresses in pavements it is needed to investigate the extent and root causes of the problem. Based on Florida highway conditions, this research study mainly focused on1. Literature review and identification of the extent of the problem; 2. Collection of relevant pavement condition data and descriptive analysis; 3. Development of statistical models to determine factors influencing the distresses in asphalt pavements on bridge approaches/departures. To the …

Electroplating On 3d Printed Conductive Track, Kishore Kumar Kadari

USF Tampa Graduate Theses and Dissertations

There are substantial advances in Additive Manufacturing (AM) technologies. The simplest and advantageous technique of AM in terms of cost and scaling of the substrate is Fused Deposition Modeling(FDM). Currently, integration of electronics to a 3D printed structure is done manually after fabrication of the structure. To print electronic circuits directly on a 3D printed structure, copper electroplating process has been studied in this work.

To electroplate on the 3D printed insulating substrate, various materials were studied to make substrate conductive. By using conductive Polylactic Acid (PLA) filaments, a compatible substrate for electroplating was printed. Electroplating was proved to be …

Enhancement Of Two Passive Decentralized Biological Nitrogen Removal Systems, Justine L. Stocks

USF Tampa Graduate Theses and Dissertations

This research evaluates two different Biological Nitrogen Removal (BNR) systems for enhanced nitrogen removal in decentralized wastewater treatment. The first study evaluated the performance of Hybrid Adsorption and Biological Treatment Systems (HABiTS) at the pilot scale with and without stage 1 effluent recirculation. HABiTS is a system developed at the bench scale in our laboratory and was designed for enhanced BNR under transient loading conditions. It consists of two stages; an ion exchange (IX) onto clinoptilolite media coupled with biological nitrification in the aerobic nitrification stage 1 and a Tire-Sulfur Adsorption Denitrification (T-SHAD) system in the anoxic denitrification stage 2. …

Electrical, Optical And Thermal Investigations Of Cobalt Oxide-Antimony Doped Tin Oxide (Coo-Ato) Thin Films And Nanofiber Membranes, Nirmita Roy

USF Tampa Graduate Theses and Dissertations

The main aim of this thesis work is to investigate the electrical, optical and thermal impact characteristics of cobalt oxide doped antimony tin oxide (CoO-ATO) in the form of thin films and nanofiber membranes. CoO-ATO is a novel composite material that has the potential to be used as reinforced aircraft coatings, military garment coatings, or more specifically as an anti-reflective (AR) top coating for photovoltaic (PV) cells. This work will be critical in determining the effectiveness of using a CoO-ATO layer in these applications. Electrospun nanofibers and spin coated thin films consisting of a polymeric solution of CoO-ATO will be …

Large Area Sintering Test Platform Design And Preliminary Study On Cross Sectional Resolution, Christopher J. Gardiner

USF Tampa Graduate Theses and Dissertations

Additive manufacturing involves the layer-wise patterned addition of material to create 3D parts, allowing for parts with complex geometries that traditional subtractive manufacturing processes cannot create, while offering good value for low run production parts by eliminating the cost of tooling. Large Area Sintering is a form of powder based additive manufacturing where entire layer cross sections are heated and fused in a single continuous exposure process. This layer by layer powder sintering process is similar to selective laser sintering, but by heating the cross section at a slower and controllable rate there is an opportunity to achieve tighter control …

Can We Re-Use “Single-Use” Solid Phase Extraction Cartridges?, Erin R. Morrison

USF Tampa Graduate Theses and Dissertations

Organic and inorganic compounds are present as contaminants in varying concentrations throughout our water cycle. Examples of these contaminants include the endocrine disrupting compounds (EDCs) bisphenol-A (BPA) and 17β-estradiol (E2) from plastics and pharmaceutical use. It can be necessary to obtain the concentration of these compounds within the water cycle for analysis by interested parties such as research groups, regulatory agencies, and private organizations. These concentrations, however, can be too dilute within the initial sample for analysis. Therefore it is necessary to concentrate the compound of interest (analyte) prior to analysis. One such way to do this is by way …

How Transportation Network Companies Could Replace Public Transportation In The United States, Matthew L. Kessler

USF Tampa Graduate Theses and Dissertations

The quantity of cell phone applications or mobile apps have seen an upsurge at an exponential rate in under a decade. Many have been created for a variety of industries, including transportation. The advent and subsequent commercialized implementation of near-instant transport by a middleman-type of app is now known as a Transportation Network Company or TNC. Examples of the more renowned TNCs are Uber, Lyft and Sidecar.

In recent years, TNCs have cultivated a tremendous following, to the degree of taxicab desertion. Moreover, the massive success of TNCs led to expansion of its capacities into public transportation.

The TNC’s expeditious …

The Effect Of Chemical Composition Of Blast-Furnace Slag On Compressive Strength And Durability Properties Of Mortar Specimens, William J. Johnson

USF Tampa Graduate Theses and Dissertations

In an effort to make structures more sustainable and durable, supplementary cementitious materials are often used to replace cement. Ground granulated blast furnace slag, for instance, is an industrial by-product of iron refinement and is frequently used in concrete mixture design to not only reduce cost, but also increase later-age strength as well as durability. However, published literature indicates that slags with a high alumina content may have a detrimental effect when concrete is exposed to a sulfate environment. ASTM standard C989 does not suggest any information or guidelines regarding using slags with an alumina content between 11-18%. Therefore, the …

Smart Inverter Control And Operation For Distributed Energy Resources, Ahmad F. Tazay

USF Tampa Graduate Theses and Dissertations

The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart …

An Evaluation Of The Water Lifting Limit Of A Manually Operated Suction Pump: Model Estimation And Laboratory Assessment, Katherine C. Marshall

USF Tampa Graduate Theses and Dissertations

With 663 million people still without access to an improved drinking water source, there is no room for complacency in the pursuit of Sustainable Development Goal (SDG) Target 6.1: “universal and equitable access to safe and affordable drinking water for all” by 2030 (WHO, 2017). All of the current efforts related to water supply service delivery will require continued enthusiasm in diligent implementation and thoughtful evaluation. This cannot be over-emphasized in relation to rural inhabitants of low-income countries (LICs), as they represent the largest percentage of those still reliant on unimproved drinking water sources. In that lies the motivation and …

Grid-Based Rfid Indoor Localization Using Tag Read Count And Received Signal Strength Measurements, Nanda Gopal Jeevarathnam

USF Tampa Graduate Theses and Dissertations

Passive ultra-high frequency (UHF) radio frequency identification (RFID) systems have gained immense popularity in recent years for their wide-scale industrial applications in inventory tracking and management. In this study, we explore the potential of passive RFID systems for indoor localization by developing a grid-based experimental framework using two standard and easily measurable performance metrics: received signal strength indicator (RSSI) and tag read count (TRC). We create scenarios imitating real life challenges such as placing metal objects and other RFID tags in two different read fields (symmetric and asymmetric) to analyze their impacts on location accuracy. We study the prediction potential …

Sustainability Of Community-Managed Rural Water Supply Systems In Amazonas, Peru: Assessing Monitoring Tools And External Support Provision, Jacob E. Mangum

USF Tampa Graduate Theses and Dissertations

Globally, there is still a large number of people without access to safe drinking water; a known health risk. In rural areas of countries like Peru, when potable water systems are built the responsibility for maintaining these systems is given to volunteer water committees. Despite its prevalence as a management model, there is a consensus that community management alone cannot ensure sustainable water service. Therefore, the overall goal of this research is to assess the sustainability of community-managed water systems in rural areas of the department of Amazonas, Peru. Specifically, this research examines two mechanisms that have been shown to …

Microfluidic Biopsy Trapping Device For The Real-Time Monitoring Of The Tumor Microenvironment, Angela Holton

USF Tampa Graduate Theses and Dissertations

The tumor microenvironment is composed of cellular and stromal components such as tumor cells, mesenchymal cells, immune cells, cancer associated fibroblasts and the supporting extracellular matrix. The tumor microenvironment provides crucial support for growth and progression of tumor cells and affects tumor response to therapeutic interventions. To better understand tumor biology and to develop effective cancer therapeutic agents it is important to develop preclinical platforms that can faithfully recapitulate the tumor microenvironment and the complex interaction between the tumor and its surrounding stromal elements. Drug studies performed in vitro with conventional two-dimensional cancer cell line models do not optimally represent …

Two Dimensional Layered Materials And Heterostructures, A Surface Science Investigation And Characterization, Yujing Ma

USF Tampa Graduate Theses and Dissertations

The isolation of single layers of van der Waals materials has shown that their properties can be significantly different compared to their bulk counterparts. These observations, illustrates the importance of interface interactions for determining the materials properties even in weakly interacting materials and raise the question if materials properties of single layer van der Waals materials can be controlled by appropriate hetero-interfaces. To study interface effects in monolayer systems, surface science techniques, such as photoemission spectroscopy and scanning probe microscopy/spectroscopy, are ideally suited. However, before these characterization methods can be employed, approaches for the synthesis of hetero-van der Waals systems …

The Fate Of Fecal Indicator Bacteria In Passive Nitrogen Reduction Systems, Michelle B. Henderson

USF Tampa Graduate Theses and Dissertations

The sustainability of water resources is an international and national concern. With increased human activity, water distribution on a global, regional, and local scale has been negatively impacted. Managing water resources also includes managing wastewater. A promising solution to the issues of water scarcity and distribution in the environment is the reuse of wastewater. Wastewater is produced from various sources (domestic, industrial, and commercial); however, if this water is able to be reused closer to the source of generation it could positively impact water distribution. In the United States, approximately 25% of domestic wastewater is treated in onsite wastewater treatment …

Advanced Treatment Technologies For Mitigation Of Nitrogen And Off-Flavor Compounds In Onsite Wastewater Treatment And Recirculating Aquaculture Systems, Laura C. Rodriguez-Gonzalez

USF Tampa Graduate Theses and Dissertations

Non-point sources (NPS) of pollution are non-discernable, diffuse sources of pollution that are often difficult to localize and in turn mitigate. NPS can include stormwater runoff, agricultural/aquaculture wastes and wastes from small decentralized wastewater treatment systems, such as conventional septic systems. The mitigation of these NPS is imperative to reduce their potential detrimental effects on the water environment. This dissertation addresses novel treatment technologies for the mitigation of nutrients, particularly nitrogen, in Recirculating Aquaculture Systems (RAS) and onsite wastewater treatment systems (OWTS). The removal of trace organics limiting RAS production and water reuse were also investigated.

The first question this …

Novel Transducer Calibration And Simulation Verification Of Polydimethylsiloxane (Pdms) Channels On Acoustic Microfluidic Devices, Scott T. Padilla

USF Tampa Graduate Theses and Dissertations

The work and results presented in this dissertation concern two complimentary studies that are rooted in surface acoustic waves and transducer study.

Surface acoustic wave devices are utilized in a variety of fields that span biomedical applications to radio wave transmitters and receivers. Of interest in this dissertation is the study of surface acoustic wave interaction with polydimethylsiloxane. This material, commonly known as PDMS, is widely used in the microfluidic field applications in order to create channels for fluid flow on the surface of a piezoelectric substrate. The size, and type of PDMS that is created and ultimately etched on …

Bisphosphonate Functionalized Gold Nanoparticles For The Study And Treatment Of Osteoporotic Disease, Christopher Conners

USF Tampa Graduate Theses and Dissertations

The use of nanoparticles for disease treatment is an increasingly popular area of research. The potential for multi-functionality allows nanoparticles to be used as transport and delivery vehicles for drugs and as diagnostic aides, among other applications, to address the unmet needs of many disease treatments. One such class of disease is osteoporosis including severe disorders, like Paget’s disease, Osteogenesis Imperfecta and Legg Calve Perthes disease. In this dissertation, we discuss a nanoparticle system consisting of gold nanoparticles surface functionalized with primary amine bisphosphonates, which is a classification of pharmaceuticals that is common in the treatment of osteoporosis. Functionalized nanoparticles …

Autonomous Vehicles: An Empirical Assessment Of Consumers’ Perceptions, Intended Adoption, And Impacts On Household Vehicle Ownership, Nikhil Menon

USF Tampa Graduate Theses and Dissertations

Emerging automotive and transportation technologies have provided revolutionary possibilities in the way we might travel in the future. Major car manufacturers and technology giants have demonstrated significant progress in advancing and testing autonomous vehicles in real-life traffic conditions. Governmental agencies are grappling with how to plan transportation systems for a world with autonomous vehicles. Past research has shown that not all technologies are immediately welcomed by the public. Autonomous Vehicles would have to likely go through a similar phase, and would need to overcome not just technological challenges but also social barriers for successful penetration into the marketplace. Most previous …

On Axon-Axon Interaction Via Currents And Fields, Aman Chawla

USF Tampa Graduate Theses and Dissertations

In this dissertation, we investigate coupling between axons in a tract, when the tract has an arbitrary cross-section, with the coupling being mediated by currents as well as electric fields. Under the current mediated setting, we develop a new master equation which captures the relative axonal geometry, specifically, the axon inclinations θ_i and the inter-axon distances W_ip and perform a number of simulations. We observe synchronization in our simulations of axons with differing diameters and separation-dependent coupling delays in the case of non-trivial tract geometries. For the field-mediated interaction setting, we determine the electric near-field of a firing …

Laser Machining And Near Field Microwave Microscopy Of Silver Inks For 3d Printable Rf Devices, Anthony J. Ross Iii

USF Tampa Graduate Theses and Dissertations

3D printable materials for RF devices need improvement in order to satisfy the demand for higher frequency and lower loss performance. Characterization of materials that have shown improvements of conductor conductivity have been performed. By using a laser machining technique the loss of a 3D printed 2.45 GHz microstrip Square Open Loop Resonator (SOLR) bandpass filter has been shown to improve by 2.1dB, along with an increase in bandwidth from 10% to 12.7% when compared to a SOLR filter that has not been laser machined. Both laser machined and microwaved silver inks have been mapped for conductivity using a Near …