Master of Science in Renewable and Clean Energy Engineering (MSRCE), Wright State University, 2024, Mechanical Engineering

Lithium-ion batteries are an integral component of energy storage systems for renewable energy applications owing to their high energy density. Extensive research has therefore been carried out, utilizing both experimental and computational methods, to aid in a deeper understanding of lithium-ion batteries. Challenges related to efficiency, safety and thermal management persist, particularly during high current draw, extreme temperature conditions and extreme dynamic current operation such as in electric vehicles. This thesis work presents an electrochemical-thermal model of a lithium-ion battery that simulates and analyzes the variation of electrical behavior, chemical behavior and thermal behavior. The electrochemical model is developed by computationally finding solutions to a set of partial differential equations that describe electrochemical and thermal processes in the anode, separator and cathode. These equations are mass conservation in electrodes (cathode and anode), charge conservation in electrodes, mass conservation in the electrolyte, charge conservation in the electrolyte, and a thermal energy balance throughout the battery. In addition, the Butler Volmer equation is used to describe the exchange of lithium ions between the solid electrodes and the electrolyte. The solutions to these equations are found using a finite volume numerical procedure implemented in MATLAB. This computational model builds on the work of Borakhadikar [1] who did not deal with the thermal issue. The results obtained by the developed program are validated against those from Smith and Wang [2] and Gu and Wang [4]. Once it is determined that the program is producing good results, a number of other results are generated for the reader to review. Profiles of the lithium-ion concentrations, profiles of the voltage, and profiles of the temperature across the battery at a given discharge level are presented. In addition, the voltage output and temperature as a function of time are g (open full item for complete abstract)

Doctor of Philosophy (Ph.D.), University of Dayton, 2024, Mechanical Engineering

Water scarcity is a growing challenge worldwide, resulting from increased population growth, industrial practices, and shifting climates. Researchers have been studying reliable, efficient, and cost effective, ways and techniques to obtain high quality fresh water using both a renewable and clean energy source such as power from solar energy or solar thermal concentration. Independent, self-operated, and low maintenance systems are highly desired for desalination systems. Deployable, solar-thermal desalination systems are promising technologies for promoting water security and sustainable community development in remote or storm-damaged coastal regions. However, these systems produce less distillate per unit energy input compared to industrial- scale desalination systems. The introduction of novel, metallic wicks in these systems increases distillate efficiency by generating an evaporation interface. It is proposed that metallic wicks with optimized micro-structure porous properties, i.e. porosity, permeability, capillary pressure, etc., will further increase distillate yields in capillary-driven desalination modules. Recent studies have demonstrated the potential of metallic wicks for increased distillate production at low-temperature (< 60 °C) operation. Many other studies assessed the quality of the distilled water, but they did not evaluate the salt accumulated at the water- vapor interface within the wick resulted from the evaporation. Another important issue that impacts the passive flow resulted from the wicking action is the dry-out that might occur within the metallic wick in the porous medium due to the evaporation process. A two-dimensional, steady-state heat and mass transfer study was performed to investigate the impact of various microstructure properties such as porosity and permeability, and environmental conditions such as solar irradiation on the distillate yield, wick dry-out, and salt diffusion/precipitation within candidate porous media struct (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Chemistry

Micrometer-size particles of the entropy-stabilized transition metal-based oxide (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O (TM-HEO) have demonstrated long-term cycling stability and excellent rate performance against lithium-ion batteries. Such a feat has only been achieved with nanometer-size transition metal binary oxides. This electrochemical performance has been attributed to the structural stabilization effect of magnesium, the intrinsic role of cobalt as the main redox active species, and the entropy stabilization effect demonstrated in this material. Here, we demonstrate the formation of single-phase so-called “medium-entropy” oxides, (Co0.25Ni0.25Cu0.25Zn0.25)O (TM-MEO(–Mg)) and (Mg0.25Ni0.25Cu0.25Zn0.25)O (TM-MEO(–Co)), and show that their electrochemical behavior is similar to that of TM-HEO. The slight difference in capacities is attributed to the number of charges stored per formula unit of material rather than the nature of TM-HEO. The mechanism of lithium interaction with these materials is still poorly understood, partly due to the difficulties characterizing structure at the nanoscale. Operando 7Li nuclear magnetic resonance (NMR) and electrochemical techniques are used to demonstrate that the (de)lithiation of these compounds proceeds via a partially reversible conversion-type reaction mechanism involving the reduction of the transition metal cations to their metallic form during lithiation and the oxidation of these individual metal particles to their oxides form, losing the initial single-phase compound after the first lithiation cycle. This proposed lithiation/delithiation mechanism highly contradicts existing ones in the literature. In addition, the 7Li NMR and electrochemical methods reveal that the conductive carbon black used as an electronic conductor can store a significant amount of charge at low voltage, indicating that it is a major contributor to the additional capacity observed in these entropy-stabilized oxides and transition metal salts. Such (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2024, Polymer Engineering

Metal halide perovskites, as an emerging and promising photovoltaic material, have drawn great concentrations in both academia and industry in the past decade. Compared to the most common silicon-based solar cells, perovskite solar cells have many advantages, such as the easy-processing and environmentally friendly manufacture. Recently, 26.7% efficiency has been certified by the National Renewable Energy Laboratory. Although this efficiency is still lower than the certified record of Si-based solar cells (27.6%), the theoretically highest efficiency of perovskite solar cells (33.7%) is higher than that of Si-based solar cells (29.4%), which indicates the huge potential of perovskite solar cells. However, there are still many issues that limit the application of perovskite solar cells, such as the stability of perovskite solar cells. Moreover, for the perovskite material itself, the severe photocurrent hysteresis and unbalanced charge carrier mobility will influence the device performance of perovskite solar cells. To solve these issues, many efforts have been made to boost the devices performance and improve the stability of perovskite solar cells. For example, the additives and surface modifications were widely reported to address stability issues. The unbalanced charge carrier mobility could be tuned by either optimizing the perovskite formula or blending other p-type/n-type materials. Furthermore, according to recent research, the main reason for the hysteresis of perovskite solar cells is the counterion migration of perovskite materials. Therefore, some organic molecules with special function groups, such as carboxyl and hydroxyl, were applied to interact with the counterions of perovskites to suppress the migration of counterions. In my research projects, my works are mainly focused on enhancing the stability and device performance of perovskite solar cells. Meanwhile, look for novel metal halide perovskite composites to reduce the photocurrent hysteresis and (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2024, Polymer Engineering

The increased use of solar energy for power is anticipated to lead to the shift from traditional power sources to renewable energy sources. Photovoltaic (PV) is a promising technology due to its ability to directly convert sunlight into electricity with no pollution. Solar cells, specifically those based on metal halide perovskites (MHPs) have gained popularity recently due to their power conversion efficiency (PCE) that have increased dramatically over the past 15 years, from 3.8% to more than 26 %. The rapid development in PCE is due to the advanced features that MHPs have such as cost-effective and easy processing, high absorption coefficient, large diffusion length, and low exciton binding energy. In particular, the purpose of this study is to develop solution-processed perovskite solar cells (PSCs) by tuning film morphology and optoelectronic properties of metal halide perovskites incorporated with processing additives, thereby optimizing the performance of PSCs. To maximize the potential of perovskite, controllable crystallization is crucial for producing high-quality perovskite thin films with fewer structural defects and additive engineering is a facile and effective method among other techniques. We mainly investigated the effects of various processing additives on the MHPs based on MAPbI3 perovskite (where MA is CH3NH3) and correlate PCE in term of film morphology, crystallinity, photocurrent hysteresis, optoelectronic properties, device performance and stability of PSCs.

Doctor of Philosophy (PhD), Ohio University, 2024, Chemical Engineering (Engineering and Technology)

Carbon steel pipelines in the oil and gas industry are susceptible to corrosion due to their exposure to corrosive gases like carbon dioxide (CO2) dissolved in the reservoir brine. These pipelines typically carry a mixture of oil, water, and gas phases. The oil phase does not cause corrosion – only the wetting of the pipe surface by water does. However, the alternating wetting of the pipeline surface by oil and water, known as "oil/water intermittent wetting", can influence the corrosion mechanisms and make the surface more resistant to corrosion even if it returns to a fully water wet state. Although extensive research has been conducted on CO2 corrosion in water-only environments, the role of the oil phase has often been far less investigated. Existing literature on the effects of oil are limited to flow patterns and phase wetting studies, with no direct correlation to corrosion rates. This study aims to develop an experimental apparatus and methodology that simulates oil/water intermittent wetting and investigate its effect on uniform and localized CO2 corrosion behavior of carbon steel. A wide range of experimental conditions, including different types of model oils containing surface-active compounds with varying concentrations, different pH values, flow velocities, elevated temperatures, and longer exposure time to oil/water intermittent wetting, were tested.

Master of Science (MS), Ohio University, 2024, Environmental Studies (Voinovich)

More than half of extremely poor Nigerians live in rural areas where the deprivation of access to basic social infrastructure such as access to reliable electricity is at its highest. About 140 million Nigerians, or around 71% of the population, do not have access to energy. Bridging Nigeria's energy deficits with a net zero target and lifting millions of Nigerians out of poverty requires enormous resources from diversified energy mix such from renewable energy and technical knowledge that cannot be sourced locally. Nigeria needs to explore encourage and maintain international bi-lateral and multilateral relationships as avenues to tap international development assistance in the form of aid and foreign direct investments for renewable energy. International development partners like the GIZ have worked in Nigeria since 1974, and operated country offices in Nigeria's capital since 2004. GIZ's projects have provided advisory services to enhance access to, use of, and investments in renewable energy, energy efficiency, and rural electrification in order to address the problem of irregular power supplies. This assistance includes the twin goals of increasing access to solar energy and to reduce carbon emissions. This thesis evaluates whether GIZ-supported efforts have increased access to renewable energy, and reduced carbon emissions. The research found out that GIZ investments have contributed indirectly to increasing renewable energy access in Nigeria between 2015 and 2022 with no evidence of carbon emissions' reduction.

Doctor of Philosophy, University of Akron, 2024, Polymer Engineering

Lithium-ion batteries (LIBs) are currently used in portable electronics because of their high specific capacity, voltage, cycle performance, and negligible self-discharge. However, their large-scale expansion is hindered by safety issues (thermal runaway) and insufficient energy density. To address LIB limitations, improvements are presented regarding solid polymer electrolytes (SPE), sulfur cathodes, and eutectic molten salts electrolytes (MSE). SPEs offer low flammability and high stability but suffer from low ionic conductivity. Our group developed a cross-linked PEGDA superionic conductive SPE, which exhibited a good ionic conductivity (above 1 mS/cm at 30 °C) and great electrochemical stability, but large-scale implementation remained a challenge. For this, a new aerosol jet-printed composite cathode was developed for a lithium metal battery that revealed an excellent performance, a specific capacity above 160 mAh/g at 60 °C and above 135 mAh/g at 30 °C with a high mass loading of 10 mg/cm2 containing LFP. Sulfur cathodes have a high specific capacity, theoretically, but significant drawbacks of low conductivity and volume expansion. Volume expansion was solved by melt-diffusing sulfur into porous Ketjen black. Conductivity improved by adding fluorinated graphite (CFx), which after chemical transformation remained carbon (of higher conductivity). Compared to the pure sulfur cathode, the hybrid cathode showed a higher specific capacity on the ratability test, and during long cycling, it had a stable capacity and a high specific capacity in the 200th cycle. The in-situ formation of a LiF protective layer was found to enhance cycling performance. MSE advantages are high conductivity and wide range in operating temperatures. However, MSE-based lithium batteries' operative conditions are restricted within temperatures of 100-170 °C, limiting potential salts to use. The lithium nitrate based molten salt, Li0.46K0.54NO3, on a primary half-cell battery exhibited a (open full item for complete abstract)

Master of Sciences, Case Western Reserve University, 2024, Materials Science and Engineering

As photovoltaic (PV) installations continue to rise and cell technologies evolve, understanding cell-level contributions to module-level failure is going to become increasingly important. Advanced Si PV architectures incorporate different materials and design combinations that influence degradation modes. Ultraviolet-induced degradation (UVID) has been identified as an understudied degradation mode for advanced cell architectures and is of increasing concern in industry due to the increasing use of UV-transparent encapsulation and bifacial technologies. In order to confidently adopt these new and evolving technologies, novel component materials and processing techniques must be evaluated and designed for long-term stability in addition to the conventional design focus on efficiency. The work presented here is three-fold and includes a review of literature relevant to known and suspected UV and light- and elevated temperature-induced degradation (LETID) mechanisms in passivated emitter and rear contact (PERC) and tunnel oxide passivated contact (TOPCon) devices, the development of a study protocol and research framework for the rapid screening of unencapsulated devices against UVID, and the results of the application of that framework to PERC and TOPCon architectures to determine device- and materials-level signatures of degradation. The literature review (Chapter 2) discusses the evolution of crystalline silicon architectures from aluminum back surface field (Al-BSF) to more current tunnel oxide passivated contact (TOPCon) and silicon heterojunction (SHJ) devices. UVID and LeTID mechanisms specific to PERC and TOPCon devices are reviewed. Unencapsulated PERC and TOPCon devices were aged under different UV irradiance intensities and measured via conventional non-destructive electrical characterization methods to assess performance degradation according to the rapid screening protocol developed and outlined in section 3.1 and Chapter 4. Based on the results o (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Chemical Engineering

The ill effects of climate change are unfolding in real time, as species and ecosystems face irreversible destruction. Climate action is needed now more than ever, as ambitious targets set by the Paris Agreement seem far-reaching in the wake of global average temperatures above 1.5C over their pre-industrial levels recorded over a continuous 12 month period for the first time. Countries, organizations, and companies alike have pledged to limit their net greenhouse gas (GHG) emissions to the environment to zero, via nationally determined contributions and corporate net-zero commitments. Such commitments remain unattainable in the absence of guidance like convergent carbon accounting methods, systems models, and roadmapping frameworks. This dissertation seeks to bridge this gap for the chemicals and materials industry (CMI). The chemical industry generates the “hardest to abate” emissions among the industrial sector due to the fixed carbon content of its products. However, as chemical energy carriers such as hydrogen and methanol gain prominence as solutions to the intermittency issues of renewable energy, the net-zero transition of chemicals becomes tied to the net-zero goals of more expansive and ubiquitous industries such as the power sector. The decarbonization of chemicals to this end, requires estimation of material and carbon flows, and baseline emissions of its current global operations. The frameworks in literature lack appropriate structure and comprehensiveness for such analysis, and relevant process and price data are inaccessible and cost prohibitive. We therefore develop an inventory of first principle based, mass balance compliant, publicly available process and cost data for CMI processes, sourced from the public domain. We devise a regression framework capable of handling conflict ridden data, and an algorithm to map resource, intermediate, product, and emission flows of any chemical system with known product capacities. The resulting Global (open full item for complete abstract)

Master of Science, The Ohio State University, 2024, Mechanical Engineering

This thesis presents a methodology for energy-efficient routing and accurate energy consumption modeling for Class 6 vehicles, including ICEVs, HEVs, and BEVs. The study integrates realistic driving conditions, such as stop signs, which significantly impact energy consumption and travel time. The detailed energy consumption model considers vehicle-specific parameters, aerodynamic drag, rolling resistance, and kinetic energy changes due to stops, enhancing the precision of energy usage estimation. This accuracy is crucial for optimizing routes, battery management, fleet operations, and infrastructure planning. The methodology involves data integration, sparse matrix representation, stop sign handling, and the calculation of energy and time metrics. Real-world data on speed profiles, distances, slopes, and stop signs are used to create a detailed energy consumption digraph for Class 6 vehicles. The model accounts for stop signs by setting final speeds to zero at specific nodes and calculating the resulting kinetic energy loss. This framework emphasizes the significant impact of stops on travel time and energy use, providing valuable insights for optimizing vehicle operations and supporting the transition to greener transportation systems.

Doctor of Philosophy, The Ohio State University, 2024, Animal Sciences

The urgent shift from fossil fuels to renewable energy sources highlights the critical need for innovative and sustainable biofuel production technologies. However, a significant hurdle in biofuel production especially butanol, pentanol, hexanol, heptanol, and octanol is the toxicity of these compounds to microorganisms. Extensive process engineering efforts, including vacuum-assisted gas stripping (VAGS), have been made towards in-situ recovery of butanol to alleviate the problem of product toxicity to producing microorganisms. Despite the success of VAGS in butanol recovery, it is still riddled with the problem of excessive water removal from the bioreactor during product recovery. The ongoing use of superhydrophobic separation materials for oil recovery in oil spillage situations indicated that there could be a way to improve water/butanol separation during in-situ recovery. Thus, this study explored the use of superhydrophobic separation materials within a VAGS system for engendering significant water retention within a bioreactor and enhancing efficient recovery of biofuels, specifically butanol and high molecular weight alcohols (C4 – C8), from fermentation broths. Central to this investigation is the development of superhydrophobic and superoleophilic stainless steel meshes (SSM) using polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE). The SSM, having a water contact angle of 156.48° was incorporated into the VAGS setup and used to enhance the recovery efficiency and economic feasibility of the biofuel production process. Experimental and modeling approaches including the use of artificial neural networks (ANN) modeling were employed to optimize the recovery conditions and assess the interplay between process parameters and system performance. Thus, the study explored the influence of several critical parameters, including mesh pore size, vacuum time, initial alcohol concentration, and bioreactor operational conditions, on the performance of th (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Industrial and Systems Engineering

Energy storage is widely used to respond to the uncertain balance of electricity supply and demand and prepare for the contingency. Among many purposes of energy storage, this dissertation will focus on arbitrage trade, peak load shift, and frequency regulation. For the first part, a two-stage stochastic programming model is introduced to schedule energy storage devices and maximize arbitrage profits for the storage operator. In addition, the model considers adjustments depending on the uncertain price of the real-time electricity market when the decision in the day-ahead market is made. Then, value of stochastic solution is computed to see effect of the stochastic programming. Furthermore, several interesting cases are observed and illustrated, such as simultaneous charging and discharging. These are considered as an sub-optimal solution in general, but this occurs in specific conditions. Second, when storage is used for peak load shift, it improves resource adequacy of the power systems by contribution of the power from energy storage. In this chapter, a non-performance penalty is imposed to ensure that energy storage operators reserve energy for such shortages. A stochastic dynamic programming model is used to obtain optimal decision policy for the storage device. Using this model, case studies are conducted for the two different systems. System load of these systems are peaked in the summer and winter, so these are analyzed and compared. In the third part, energy storage capacity value and expected profits are estimated when it provides energy, capacity, and frequency regulation services. To estimate capacity value, three steps approach is adopted. First, discretized stochastic dynamic programming is used to obtain decisions policies for the discretized states. These decision policies are used to get actual decisions by solving mixed-integer optimization in a rolling-horizon fashion. Then, capacity value of energy storage is estimated using simulation. A case (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 0, Polymer Science

Lithium-ion batteries (LIBs) are crucial energy sources across diverse sectors, from medical devices in nanotechnology to grid energy storage. However, their liquid electrolytes pose significant safety risks, particularly during overheating, leading to battery explosions. This hazard is especially pronounced in electric vehicles, where breaches can trigger catastrophic cell explosions. Solid-state batteries (SSBs) have emerged as a promising alternative, offering enhanced safety by replacing liquid electrolytes with solid-state electrolytes (SSEs). Despite this, scaling up LIB production and improving energy and power density remain significant challenges. Chapter I presents a novel approach using 3D printing technology to fabricate solid polymer electrolyte membranes for SSBs. This method replaces conventional polymer separators and liquid electrolytes with a thin, ionically conductive composite based on poly(ethylene glycol) diacrylate (PEGDA) reinforced with polyamide for mechanical strength. Using a digital light processing (DLP) 3D printer, we created thin SSE films. Lithium plating/stripping tests showed that the printed PEGDA/polyamide electrolyte maintained stable cycling performance over 1,400 hours at a current density of 0.05 mA/cm². Additionally, LIBs with the 30 μm polyamide-reinforced electrolyte exhibited excellent cyclability at a 0.2 C rate under ambient conditions (30°C). Chapter II addresses issues with traditional cathode electrode processes, such as the insulating polyvinylidene fluoride (PVDF) binder and toxic organic N-methyl-2-pyrrolidone (NMP) solvent. We introduced a solvent-free electrode processing technique using a thermal cross-linkable polymer electrolyte as a binder substitute. This method allows the creation of higher mass loading electrodes without volatile organic compounds (VOCs). Cathode electrodes were prepared on the current collector using hydraulic thermal pressing, with adjustments to the pressing force. Structural parameter (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2024, EECS - System and Control Engineering

This thesis presents a pivotal study focused primarily on the application of Multi-Criteria Decision Making (MCDM) methodologies to identify the most suitable locations for wind farm development across thirteen regions in Saudi Arabia, an endeavor underscored by the country's significant potential for renewable energy. This research takes into account critical factors such as average wind power density, wind speed, and terrain suitability to guide the decision-making process. In parallel, the thesis also revisits an ancillary study based on a 1987 mode choice survey involving 210 travelers making trips between Sydney, Canberra, and Melbourne, offering a comparative perspective on the utility of MCDM methods across distinct domains. Employing an extensive array of MCDM techniques—including Linear Additive Utility functions, Geometric Dispersion Theory models, Keeney Multiplicative Utility (both with and without value functions), and a Z-Goal-programming method tailored for wind farm location selection and Transportation Mode selection—this analysis is thorough in its critical evaluation of these methodologies' efficacy in forecasting optimal choices. The precision of these models is quantitatively assessed using the Sum of Squares Error (SSE) metric, complemented by a thorough validation framework that includes both a 70% in-sample and a 30% out-of-sample comparison, alongside comparative assessments across models. The culmination of this research underscores the unparalleled predictive prowess of Geometric Dispersion Theory (GDT) models, which demonstrated the lowest SSE, thereby affirming its superior capability in accurately determining optimal wind farm locations in Saudi Arabia. By extension, the GDT models' effectiveness was also mirrored in the mode choice study, further attesting to their robust applicability across different decision-making contexts. This thesis enriches the academic discourse on MCDM applications within the realms of renewable energy site (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 0, Chemical Engineering

Carbon capture and plastic waste upcycling are both effective strategies for combatting climate change by reducing CO2 emissions in the atmosphere. Carbon capture technology is characterized by three major methods: (i) post combustion capture (ii) pre-combustion and (iii) oxy-combustion. CO2 absorption, which is a type of post-combustion technology, is reported to be the dominant capture technology. The overall performance of this process is majorly determined by parameters such as CO2 capture capacity, amine efficiency and binding energy. A key issue of the CO2 absorption process is the development of a sorbent that will effectively absorb CO2 in a stream of flue gas and then release it in such a way that the sorbent is not thermally degraded, clean, and ready for re-use. The release of the captured CO2 typically involves the use of elevated temperatures for regeneration of the sorbent which leads to high energy penalty, solvent loss, corrosion, and high operation costs. This research focuses on the application of an in-situ infrared spectroscopic (IR) approach to study the structure of adsorbed CO2 species and reaction mechanism during CO2-amine reactions under pure CO2 and direct air capture cycles as a method of developing cost-effective and energy efficient sorbents. The band assignments of these species are identified by HCl probing. In addition, we explore alternative routes for regeneration that involve the coupling of renewable energy in the form of electricity to generate non thermal plasma with in-situ infrared (IR) spectroscopy to separate adsorbed CO2 from novel developed polyamine sorbents. We explored the reaction mechanism of non-thermal plasma induced reaction for the release of adsorbed CO2 from solid amine sorbents packed in a glass cylindrical tube reactor. The lead vs lag relationship of released CO2 and other products are investigated and characterized. Furthermore, we apply the concept of plasma-enabled gas-phase electrocatalysis for an effi (open full item for complete abstract)

Master of Science in Engineering, Youngstown State University, 2024, Department of Mechanical, Industrial and Manufacturing Engineering

This research investigates the optimization of vertical axis wind turbine (VAWT) systems to harvest energy from vehicle-induced highway winds. The primary objective is to enhance the efficiency of small-scale VAWTs mounted on the side of highways, enabling the generation of electrical energy or clean hydrogen production. Computational fluid dynamics (CFD) modeling was employed to systematically optimize the turbine design and to develop wind guides that further increase the efficiency. The study found that an elliptical VAWT design demonstrated a 4.4% higher power coefficient compared to a Savonius VAWT. Introducing a single flat or curved guide between the turbine and the road increased the power output by 145.33%. Further refinements, including the use of three guides with optimized angles and radii, culminated in a remarkable 393.16% improvement over the initial non-guided-guided configuration. In the non-guided-guided scenario, simulating the VAWT's exposure to the wake flow induced by a bus traveling at 32 m/s, the CFD analysis predicted an energy output of 30.41 Nm. However, when the three guide vane configuration was employed, the energy output exhibited a substantial increase, reaching 100.41 Nm under the same bus speed conditions. The comparative analysis between the Non-guided-guided and three-guide vane setups for the bus wake simulations revealed a remarkable 230% enhancement in energy capture when the guide vanes were incorporated. This significant performance improvement highlights the favorable impact of the optimized guide vane arrangement on the aerodynamic behavior of the VAWT, facilitating more effective extraction of energy from the wake flows generated by larger vehicles such as buses. The results showcase the significant potential of vehicle-induced highway winds as a viable source of renewable energy. The optimized VAWT system, incorporating multiple flow guides, demonstrates the ability to effectively harness this untapped resourc (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 0, Polymer Engineering

As the demand for next-generation batteries rises, the present dissertation is designed to illustrate the governing principles and novel technologies via development of multifunctional polymer electrolyte membrane for energy storage devices such as lithium-ion batteries and supercapacitors. Customarily, polymeric materials have been used to afford mechanical support as membrane separators and ion transport through liquid electrolyte media of energy storage devices, which are currently dominated by ceramic or inorganic metal oxide electrodes. The ultimate goal is aimed at understanding how polymer electrolyte matrix (PEM) can enhance both energy and power density beyond those afforded by the electrode active materials. Chapter 3 delves into the innovative application of polymer materials in battery formulation, leveraging ion-dipole complexation within a multifunctional polymer electrolyte membrane (PEM). This complexation entails the interaction between lithium ions, ether oxygen, and amine groups within the thermally cured poly(ethylene glycol) diglycidyl ether (PEGDGE) and polyether amine co-network. While this process may temporarily hinder ion transport, resembling temporary lithium ion storage, the prelithiation process ensures excess lithium ions for transport, enhancing PEM energy storage capacity and ionic conductivity. Additionally, diffusion, facilitated by ion concentration gradients in bilayer PEM composites, aids in supplying lithium ions to the PEM. The emergence of redox reactions, as demonstrated by cyclic voltammetry (CV) measurements, further supports the energy storage strategy of multifunctional PEM networks. In Chapter 4, the energy storage concept is exemplified through a high Ni-cathode, leveraging chemical reactions at the electrode-PEM interface. Introducing a PEM composed of a polysulfide and polyoxide blend with succinonitrile and LiTFSI salt enhances ion transport and storage capacity, exhibiting a conductivity of 1.18 x10-3 S/cm at (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Industrial and Systems Engineering

This dissertation investigates the optimization of real-world energy applications, focusing on power and gas networks. These systems pose challenges due to their complex governing laws and practical considerations, leading to nonlinear optimization models that are often non-convex. Recent advancements in operations research, including relaxation and reformulation techniques, have provided avenues to tackle non-convexities. This dissertation delves into exponential conic programming (ECP) techniques, addressing two classical non-convex problems in power and gas networks. In power systems, the dissertation proposes a novel convexification technique through ECP reformulation to enhance system reliability. Similarly, in gas networks, this dissertation provides relaxation models based on ECP principles to solve signomial geometric programming (SGP) problems, demonstrating practicality and effectiveness. Through these efforts, the dissertation aims to advance optimization techniques for improving the reliability and operational efficiency of energy networks.

Master of Science (M.S.), University of Dayton, 2024, Chemical Engineering

There is a continuous thrust for cleaner and more sustainable alternatives for energy conversion with the increasing global energy demand. Among them, photovoltaics, specifically thin film solar cells are highly promising and are one of the fastest growing clean energy technologies in the United States. This research presents the synthesis and characterization of a set of novel multinary copper chalcogenide semiconductor nanocrystals (NCs), CuZn2ASxSe4-x consisting primarily of earth-abundant elements for applications in photovoltaic devices. A modified hot-injection method was used to synthesize these semiconductor NCs containing both S and Se chalcogens. The novelty of the new semiconductor NCs lies in the incorporation of multiple cations as well as two different chalcogen anions within the crystal lattice, which is an achievement from the materials synthesis aspect. The composition-controlled optical and photoluminescence properties of the CuZn2ASxSe4-x NCs were investigated via multi-modal material characterization including x-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence spectroscopy (PL). The crystal structure, as determined from the XRD primarily consisted of the metastable wurtzite (P63mc) phase. The NCs exhibited direct band gap in the visible range that could be tuned both by varying the group III cation within the composition as well as the ratio of S/Se, based on the Tauc plot obtained from the UV-vis characterization. This work lays the groundwork for future investigations into the practical applications of copper chalcogenide NCs in solar energy conversion.