Engineering Commons^™

Integration Of Algae And Biomass Processes To Synthesize Renewable Bioproducts For The Circular Economy, Jessica Martin

USF Tampa Graduate Theses and Dissertations

Rapid population growth and global industrialization have substantially heightened the demand for fossil-based fuels and products in various sectors of the global economy, including energy production, transportation fuels, and as raw materials for petrochemicals. The intense consumption of fossil fuels has caused immense environmental impacts, especially pertaining to carbon dioxide emissions. Shifting to renewable feedstocks (raw materials) is expected to reduce these emissions by lowering the carbon footprint of fuels and products compared to traditional fossil-derived alternatives. This transition aligns with the goal of creating a sustainable and circular economy, emphasizing efficient resource use, and reducing waste generation through recycling …

Swelling Induced Buckling Of Photopatterned Hydrogel Beams, Chinar Yogesh Kokaje

USF Tampa Graduate Theses and Dissertations

The main goal of this study was to learn more about swelling induced buckling of surface-attached gel lines photo-patterned from thermally responsive polymers. A library of 10 different polymer compositions was synthesized using methacryloyloxybenzophenone (MABP) as the photo-cross-linking monomer. For each of the polymers, a series of beam-like patterns were prepared on polystyrene tissue culture dishes by first depositing a known amount of polymer into the tissue culture dish followed by pattern generation using a photo-lithography mask with line widths of 10, 20, 30, 50, and 80 μm. The target height of each polymer line was 100 μm. After development …

Wastewater Treatment Using Encapsulated Chabazite In Polyvinyl Alcohol-Sodium Alginate Hydrogel Biofilm Carriers, Susieanna Nevada Persaud

USF Tampa Graduate Theses and Dissertations

Nitrogen discharge from wastewater is a global issue and with increased urbanization as well as industrialization, it has become even more essential to develop more efficient wastewater treatment systems. The dominant form of nitrogen in wastewater is ammonium. Biological oxidation of ammonium to nitrite and nitrate is the first step in biological nitrogen removal processes. If left untreated, nitrogen can cause toxicity to aquatic life, unsafe changes in water quality, and eutrophication.

Biofilm carriers can help to improve the efficiency of traditional activated sludge wastewater treatment systems by reducing operating costs and reducing hydraulic retention time. Biofilm carriers also promote …

Evaluation Of Aluminum Dissolution, Current Density, And Pitting Patterns During Electrocoagulation, Monica Castro Carias

USF Tampa Graduate Theses and Dissertations

Electrocoagulation (EC) is a sustainable water treatment process involving the generation of coagulants on-site through the application of a voltage on metal (usually aluminum or iron alloys). The factors that impact EC system performance have been well researched, however further research is needed on the factors that impact anodic dissolution of aluminum electrodes, especially when the technology is transferred to full-scale applications. Electrode fouling is one of the factors that can impact dissolution of the anode during EC due to the formation of a protective oxide/hydroxide layer on the electrode surface. Previous studies have addressed electrode fouling by reversing polarity, …

Techno-Economic And Sustainability Analysis Of Renewable Natural Gas (Rng) Production, Eesha Bhattacharjee

USF Tampa Graduate Theses and Dissertations

Natural Gas (NG) is one of the major sources of energy currently used in the United States. Its major applications include generating electricity, domestic, and industrial heating purposes and as a transportation fuel. The largest component of NG is methane, and it contains trace amounts of hydrocarbons, some CO2 and water vapor.

Biogas (produced by anaerobic digestion (AD) of biomass) upgraded to have high purity methane (often termed as biomethane or renewable natural gas) can be used as an alternative to NG. The upgrading techniques may include CO2 separation from the biogas stream or via to a methanation facility where …

Computationally Driven Design Of Shape-Controlled Polymeric Nanostructures, Davindra Tulsi

USF Tampa Graduate Theses and Dissertations

In the realm of shape control involving synthetic soft materials, block copolymers are ubiquitously exploited due to their ability to spontaneously self-assemble into a plethora of morphologies. The growing need in areas such as drug delivery, lithography, and microelectronics to generate new nanostructures demands ever finer control of copolymer self-assembly. It is desirable to better control the shape and size of soft nanostructures, with minimal post processing techniques to assert stability.

While there is an abundance of literature on diblock copolymer assembly, few relationships exist for sequence-controlled copolymers. It is well known that biological macromolecules are highly sequence specific and …

Multi-Material Hybrid Additive And Subtractive Manufacturing Of Photonic Devices, Roger Brandon Tipton

USF Tampa Graduate Theses and Dissertations

Optoelectronics focuses on the application of electronic devices that utilize forms of electromagnetic radiation including visible light and other wavelengths including ultraviolet and infrared. Optoelectronics typically include devices that emit light and detect light. Devices created using this technology include light-emitting diodes, laser diodes, photoresistors, photodiodes, solar cells, phototransistors, and fiber optics. Fiber optic interconnects are interesting devices in that they are used in conjunction with optoelectronic devices to transmit information between individual optoelectronic components.

Optoelectronics are typically produced by traditional lithography methods including etching, writing, and printing on rigid silicon substrates for fabricating devices. Other techniques like glass or …

Material And Topographically Optimized Thermal Dissipation For High-Performance Electronic Devices Utilizing Vapor Chambers, Derek Joseph Daniels

USF Tampa Graduate Theses and Dissertations

Advances in materials science and engineering in the field of thermal transport and dissipation enable the use of higher-performance electronic devices that are smaller and generate more heat. Phase change thermal transport systems such as heat pipes and vapor chambers enable passive dissipation from devices that generate excessive heat without the need for actively pumped cooling systems. Properly designed vapor chamber enabled systems easily exceed the thermal conductivity of manufactured diamond at a small fraction of the cost.[1][2][3] While heat pipe phase change systems are generally one-dimensional with a limited cross section, vapor chambers are generally two-dimensional with a small …

Vermiculations In Painted Caves: New Inputs From Laboratory Experiments And Field Observations, Perrine Freydier, Eric Weber, Jérôme Martin, Pierre-Yves Jeannin, Béatrice Guerrier, Frédéric Doumenc

International Journal of Speleology

Vermiculations are aggregates of small particles commonly found on cave walls. They are a major concern for the conservation of painted caves, as they can potentially alter valuable prehistoric cave paintings. A previous rheological study of fine sediment deposits on cave walls revealed that this material can undergo a solid-to-liquid transition triggered by variations in the chemical composition of the water film on the wall. Such a transition could occur at the origin of vermiculations by allowing the sediment to flow under low mechanical stress. In this work, we provide quantitative information on the conditions leading to this transition and …

Water Regulation For Enhancing Soil Quality Using Cactus Mucilage: A Theoretical And Experimental Analysis, Khuloud Alrashdi

USF Tampa Graduate Theses and Dissertations

As water is one of the primary sources of life, it is essential in an endless number of systems and processes to be utilized efficiently in nature and in practical applications. One of these applications includes farming, which depletes a lot of water as the water irrigation systems cover large soil areas. While water is a critical factor in growing crops, a question here stands, can the irrigation process be transformed? This is the overarching goal of my work since it is centered on studying if cactus mucilage, a natural substance, is capable of improving water absorption processes on crops …

Mutational Analysis Of Latency Associated Peptide For Therapeutic Application, Johnny Will Stephens

USF Tampa Graduate Theses and Dissertations

TGF-β is an important protein for regulation of the immune system, and has been linked to promotion of tumor progression and cancer growth. Inhibiting TGF-β has been shown to be an effective therapeutic technique for fighting multiple cancer types. Engineering TGF-β’s natural inhibitor, Latency Associated Peptide (LAP), to improve its biophysical properties has potential to increase therapeutic efficacy.

Rosetta and FoldX can be used in concert to engineer stabilizing mutations of proteins. In accordance with this, PyRosetta and FoldX were used to predict stabilizing mutations of LAP. The most stabilizing mutations from each program were combined with mutually predicted mutations. …

Preparation And Characterization Of Single Layer Conducting Polymer Electrochromic And Touchchromic Devices, Sharan Kumar Indrakar

USF Tampa Graduate Theses and Dissertations

Electrochromic devices (ECDs) have triggered great interest because of their potential applicability in energy-efficient buildings and low power display systems, including reflective type smart windows/mirrors and wearable-flexible devices. In the past decades, electrochromic technologies with different device structures and materials have been proposed. The idea of employing a simple device structure with a durable, cost effective electrolyte is crucial to designing and manufacturing high-performance ECDs. With this idea in mind, this thesis describes the various efforts to develop a simple ECD comprising of a composite single active layer gel electrolyte, sandwiched between two transparent conducting electrodes, lasting over 10,000 cycles …

Investigation Of Polymer-Plasticizer Blends For Btex Detection Using Quartz Crystal Microbalance, Abhijeet Iyer

USF Tampa Graduate Theses and Dissertations

Volatile organic compounds (VOCs) are chemicals that evaporate easily and become gases at ambient temperature and pressure. The EPA has made the monitoring of VOCs mandatory due to their health impacts, which range from headaches and nausea to cancer. The current techniques used for VOC monitoring such as photoionization, gas chromatography, mass spectroscopy, and e-noses sensors are expensive, time-intensive, demand rigorous sample preparation, and cannot quantify the VOCs in the air. Chemical sensors based on piezoelectric transduction like the quartz crystal microbalance (QCM) show promising results in terms of providing cost-effective real-time data, robustness, and low power requirements. In this …

A Barker Type Approach For Measuring And Interpreting Vle Of Polymer Mixed Solvent Systems, Vaishali Jain

USF Tampa Graduate Theses and Dissertations

The environment around us has a great impact on human health. A polluted environment can adversely impact human health and cause diseases like cancer, skin diseases, breathing problems and many more and hence altering the quality of life. Hence it is very important to develop sensors that can efficiently detect these harmful substances from environment. Volatile organic compounds (VOCs) are carbon-based chemical substances that are volatile even at ambient temperature and pressure conditions which enter the atmosphere through industrial processes, building materials, etc.

Acoustic wave devices can detect very low concentrations (ppm, ppb) of organic compounds in the environment. A …

Corrosion Rate Prediction In Frp-Concrete Repair, Mohammad A. Khawaja

USF Tampa Graduate Theses and Dissertations

Research has proven that wrapping structural elements with fiber-reinforced polymers (FRPs) slows down chloride-induced corrosion rate but does not stop it. Although FRP has been used for corrosion repair for over 40 years, predictive corrosion rate models for FRP-concrete systems are limited in literature. This dissertation presents an oxygen diffusion-based predictive framework to estimate corrosion rate in FRP-concrete systems.

The dissertation has three main components. First, a core framework that is referred to as Khawaja-Sen-Bhethanabotla (KSB) model. In the KSB model, statistical methods were used to extend experimental data on oxygen permeation coefficients. These data were for one and two …

Plasmonic Photocatalysis For Gas-Phase Degradation Of Total Volatile Organic Compounds: Theory, Experimentation, And Catalyst Stability, Amaury P. Betancourt Iii

USF Tampa Graduate Theses and Dissertations

Plasmonic nanomaterials have become a strong contender for improving the efficiency of photocatalytic degradation of air pollutants. This study demonstrates an easy and scalable fabrication method, employing electron beam evaporation and rapid thermal annealing, for producing plasmonic photocatalysts. Samples were made by either coating silver on, or layering silica-protected (i.e., silica-coated) or unprotected (i.e., uncoated) silver beneath, the photocatalyst (either zinc oxide or titanium dioxide). Stability and catalytic performance for gas-phase toluene degradation was assessed by monitoring total volatile organic compound (TVOC) concentration versus ultraviolet-A (UV-A) illumination time in a recirculating batch reactor (plate-type flow-through). Samples were characterized using a …

An Investigation Of Cross-Links On Crystallization And Degradation In A Novel, Photocross-Linkable Poly (Lactic Acid) System, Nicholas Baksh

USF Tampa Graduate Theses and Dissertations

Polymeric molecular structure consists of repeating units bonded together. Mechanicalproperties can be altered without affecting chemical makeup by altering the number of these units. Small molecules can be introduced and/or polymers can be modified to form bonds between molecular chains. Cross-linking, as this is called, also introduces mechanical variation with minimal effects on chemical composition. Lastly, polymer chains reorient themselves in response to intermolecular forces. This temperature dependent response is known as crystallization. Although chemistry is unaltered, mechanical properties can depend highly on the percent of the sample that is crystallized.

Cross-linking is known to enhance the mechanical properties of …

Biogas Upgrading Via Solid Resin-Based Amine Sorbents, Olusola Johnson

USF Tampa Graduate Theses and Dissertations

Biogas is a valuable renewable energy generated from anaerobic digestion of biodegradable organic matter. It is applicable as fuel in vehicles, for the generation of electricity, industrial heating, or as raw material to produce chemicals, liquid fuels, syngas, and compressed natural gas (CNG). Carbon dioxide (CO2) and methane (CH4) are the major components in biogas, with a trace amount of contaminants, including hydrogen sulfide (H2S), water vapor (H2O), nitrogen (N2), ammonia (NH3), oxygen (O2), carbon monoxide (CO), halides, volatile organic compounds (VOCs), siloxanes, and hydrocarbons.

The source of biogas, which is anaerobic digestion of different organic matter or landfill decomposition, …

Low-Grade Kaolin Clay Natural Resource For Use As A Supplementary Cementitious Material In Structural Concrete Elements, Brandon X. Lorentz

USF Tampa Graduate Theses and Dissertations

At the turn of the century, low-grade kaolin clay (LGK) was presented as a widely available and potential natural resource of supplementary cementitious materials (SCM) for producing high performance concretes. In using LGK as an SCM, clinker production is reduced, aiding environmental concerns with associated CO2 emissions. These types of clays have very heterogeneous mineralogy and microstructural characteristics, causing unique influences on concrete structural and flow performance, although these influences are not well understood. This research studies LGK natural to the state of Florida and assesses their potential use as high performance SCM.

Ten kaolin clays were obtained through a …

Cactus-Based Mucilage As A Natural Dispersant For Crude Oil Spills, Fei Guo

USF Tampa Graduate Theses and Dissertations

Oil spills are a critical threat to the marine environment, and the spilled oil as a source of pollution can have long-term adverse effects on the marine ecosystem. Traditional mechanical clean-up operations have apparent advantages for dealing with small and medium-scale oil spills. For large-scale oil spills, dispersants are a practical and minimally influential approach to the environment. As the dispersant components are iteratively updated, dispersants become more efficient and safer. However, the toxicity of the dispersants remains a significant impediment to their application. An efficient and non-toxic dispersant is increasingly becoming a requirement.

The cactus mucilage extracts studied in …

Effects Of Reservoir Conditions And Trace Co-Contaminant Gases On Geological Carbon Sequestration, Ram Kumar

USF Tampa Graduate Theses and Dissertations

Geological carbon sequestration in a saline formation is a promising technology for large-scale carbon dioxide (CO2) mitigation. Several factors such as temperature, pressure, salinity, hydraulic conductivity, and mineralogy of a formation affect the CO2 sequestration in saline formations. These factors can vary widely depending upon the type of formation or the degree of heterogeneity within a formation. In addition to these properties of the repositories, the CO2-rich flue gas streams captured from point sources often contains small amounts of impurities such as sulfur oxides (SOx) and nitrogen oxides (NOx), which may have serious implications on the chemistry of the repositories …

Responsive Coatings And Functional Systems From Pectin Polysaccharides, Zeinab Veisi

USF Tampa Graduate Theses and Dissertations

Pectin polysaccharides provide promising potential as all-natural, non-toxic “green” coatings. Pectin polysaccharides have been drawing growing attention as elements of stimuli-responsive systems and as source materials for functionalized robust coatings. They can be extracted from several natural sources and are intrinsically biocompatible. The majority of the applications of pectin gels require a better understanding of the properties of thin layers of gels at surfaces and interfaces. Despite the prevalence of bulk gels of pectin, coatings of pectin have not been reported. In bulk hydrogels, swelling of polymer networks is controlled by a diffusion limited transport process in which the rate …

Carbon Dioxide Adsorption Using Solid Amine Sorbents, Umadevi Gopalakrishnan

USF Tampa Graduate Theses and Dissertations

Biogas, being rich in methane, can be used as a fuel for various end uses such as electricity generation, compressed natural gas (CNG), production of liquid fuels, industrial heating, etc. CO₂ is the major contaminant in biogas (30–50%) along with other impurities such as NH₃, H₂S, and water. CO₂ in the biogas decreases the heating value of biogas. Natural gas pipelines and vehicle use require high purity (> 95%) CH₄. There are many commercial techniques available for CO₂ removal from biogas such as such water scrubbing (WS), chemical scrubbing (CS) using …

Effect Of Promoter (Mn) On The Performance Of Sba-15 Supported Iron Catalysts For High Temperature Fischer-Tropsch Synthesis, Sreya Mariya Seby

USF Tampa Graduate Theses and Dissertations

Development of an effective High Temperature Fischer-Tropsch Synthesis (HTFTS) catalyst is of interest in process intensification that combines methane reforming with long chain hydrocarbon production. Literature indicates iron catalysts supported on mesoporous silica performed relatively well in high temperature applications. In this work, we investigated the effect of manganese promoter on iron catalysts for FTS at 430 °C as it was known from previous studies that manganese promotion could enhance the CO conversion with higher hydrocarbon yields. Also, the effect of temperature on FTS activity was evaluated by testing the base and promoted Fe/SBA-15 catalysts for temperature ranging from 370 …

Sorption Of Benzene, Tolueneand Ethylbenzeneby Plasticized Pema And Pema/Pmma Sensing Films Using Aquartz Crystal Microbalance (Qcm) At 298.15k, Deekshitha Adapa

USF Tampa Graduate Theses and Dissertations

Detection of volatile organic compounds (VOC’s) in the environment is important for human health and wellness. Long term exposure of certain VOC’s like benzene, toluene, ethylbenzene and xylene (BTEX) has a severe effect on human health. There are techniques such as gas chromatography, photo ionization, and mass spectroscopy that are time consuming, require gas sampling and are ineffective in real time sensing in air. Acoustic wave devices such as surface acoustic wave (SAW) devices can be used for sensing BTEX compounds in both vapor and liquid phase. The quartz crystal microbalance (QCM) is a low-frequency acoustic wave device, which can …

Enhanced Co2 Conversion By The Simultaneous Doping Of Co, Fe, And Mn In The B-Site Of A Lanthanum Perovskite, Adela E. Ramos

USF Tampa Graduate Theses and Dissertations

There is a pressing need for carbon dioxide (CO₂) mitigation technologies as increasing emissions continue to threaten our environment. Carbon capture and storage (CCS) alone would not be able to achieve temperature rise below 2 °C. In addition, CCS cost increases considerably for power generation and other industries where CO₂ separation is necessary. Conversion of CO₂ to usable products is the most economical and feasible solution as it could offset CO₂ separation cost. Liquid fuels are an attractive route since it is a commodity used globally and demand increases with population and economic growth. Conversion …

Sorption Of Benzene, Toluene And Ethylbenzene By Plasticized Poly (Ethyl Methacrylate) Using Quartz Crystal Microbalance At 298.15k, Kiranpreet Kaur

USF Tampa Graduate Theses and Dissertations

Quartz crystal microbalances (QCM) are chemical sensors used for liquid and vapor sensing. In this thesis work, plasticized poly (ethyl methacrylate) (PEMA) coated QCM was used to study sorption behavior of benzene, ethylbenzene and toluene in respective polymer at 298.15K. Poly (ethyl methacrylate) (PEMA) is a promising polymer with solubility parameter close to BTEX compounds, but it's glassy and rigid nature at room temperature make it less sensitive. The addition of plasticizers (Diisononyl cyclohexane-1,2-dicarboxylate (DINCH) and Diisooctyl azelate (DIOA)) lowers the glass transition temperature, provides flexibility and thus increases the free volume of the polymer to enhance analyte sorption. In …

Effect Of Heating On Heat Capacity Of Vegetable Oils Used For Biofuel Production, Sailee Nitin Nagpurkar

USF Tampa Graduate Theses and Dissertations

Biodiesel has become a major renewable fuel for diesel engines particularly from various waste sources. New biodiesel production technologies are emerging with data demands for efficient process design. This project highlights the data requirements, gaps in the thermo-physical property data, and consolidation of experimental and estimation methods for effective process development. Knowing the thermodynamic properties of a substance is important in order to know what process or procedures it has to go under. The aim of this project is to assess the potential of vegetable oils to serve as feedstock for biofuel production by determining their heat capacity (Cp). Such …

Photocatalytic Carbon Dioxide Conversion To Fuel For Earth And Mars, Anne J. Meier

USF Tampa Graduate Theses and Dissertations

As far as we know, we only have one planet to live on, with a delicate atmospheric system providing us safety and life. Global CO2 emissions continue to plague the environment of Earth, primarily due to the processing of fossil fuels, deforestation, and industrialization. There are several avenues of pursuing CO2 reutilization, each having their own benefits and limitations. Direct and indirect thermochemical approaches of CO2 conversion boast of efficient CO2 conversion rates but have limitations associated with the use of renewable hydrogen and high temperatures of operation. The work in this dissertation investigates low temperature photocatalytic CO2 conversion, a …

Defect Laden Metal Oxides And Oxynitrides For Sustainable Low Temperature Carbon Dioxide Conversion To Fuel Feedstocks, Debtanu Maiti

USF Tampa Graduate Theses and Dissertations

The current energy and environmental scenario in the world demands acute attention on sustainable repurposing of waste CO2 to high value hydrocarbons that not only addresses the CO2 mitigation problem, but also provides pathways for a closed loop synthetic carbon cycle. Difference in the scales of global CO2 emissions (about 40 Gtpa, 2017) and the carbon capture and sequestration (CCS) facilities (estimated cumulative 40 Mtpa, 2018) provokes active research on this topic. Solar thermochemical (STC) and visible light photocatalysis are two of the most promising routes that have garnered attention for this purpose. While STC has the advantages of high …