Master of Science, Miami University, 2023, Chemical, Paper and Biomedical Engineering

Microbial bioproduction offers several advantages compared to traditional chemical synthesis, including renewable substrates, enzymatic catalysis, and processing under labile conditions. We hypothesize that sigma factors, naturally used by cells to shift metabolic states, can be used similarly to direct expression and resources toward heterologous pathways. We have investigated this competition through the controlled and induced expression of non-native, alternative sigma factors B, G, and F from B. subtilis in E. coli. Our results indicate a decrease in cellular growth amount as measured using optical density for all three sigma factors when produced from a pBAD24 plasmid. We believe decreases in cell growth are due to sigma factor competition for RNA polymerase resources, with the highest competition observed in stationary phase. Sigma factor F had the largest impact on cellular growth in the exponential phase. Over-expression of an anti-sigma factor for the E. coli housekeeping sigma factor did not result in changes in cellular growth, indicating simple addition of this protein does not impact competition for RNAP.

Committee: Jason Boock (Advisor); Kevin Yehl (Committee Member); Justin Saul (Committee Member) Subjects: Biomedical Research; Chemical Engineering

Master of Science, The Ohio State University, 2023, Chemical Engineering

Decision making and optimization are core aspects of many real-world engineering problems, ranging from process optimization to experimental design. Many of these systems are black-box and expensive to evaluate which causes many traditional optimization methods to be difficult to implement in these systems. Additionally, many systems experience heteroskedastic noise when collecting data which many optimization strategies can not account for. Bayesian optimization has successfully been able to use surrogate models to create an easier to optimize system which can be updated by introducing new samples. Bayesian optimization requires the use of surrogate models, most commonly Gaussian processes, to model the sampled data, and acquisition functions to find optimal locations for sampling new points. Traditional Gaussian processes have been unable to heteroskedastic noise in data which led to the development of the heteroskedastic Gaussian processes (HGP). These HGPs are capable of properly accounting for noise in the data and can make more accurate predictions on regions without samples. Acquisition functions however have difficulty handling noise, and the most capable of handling this noise, knowledge gradient, is difficult to optimize and evaluate. This thesis focuses on a new method for implementing knowledge gradient and using knowledge gradient for enhanced decision making. In order to ensure global optimality of the knowledge gradient function, grid based methods generally must be implemented which are inefficient and lead to gaps in the sampling space. A new method, neural network knowledge gradient (NNKG), uses randomly generated initial sampling data to more efficiently explore the sample space and interpolate between samples. This method when compared to the traditional method also allows for enhanced visualization of the knowledge gradient surface which allows for greater understanding in regions of value and enhanced decision making on where to sample next (open full item for complete abstract)

Committee: Bhavik Bakshi (Committee Member); Joel Paulson (Advisor) Subjects: Chemical Engineering

Doctor of Philosophy (PhD), Ohio University, 2022, Chemical Engineering (Engineering and Technology)

Electrochemical nitrogen reduction has been proposed as a potential means of generating ammonia sustainably in comparison with the current industrial process. The possibility of using green hydrogen sources to produce nitrogen would allow for the production of this vital molecule while producing much less greenhouse gas. Significant challenges must be addressed for an electrochemical ammonia synthesis process to become feasible, most notably the dominance of the competing hydrogen evolution reaction which prevents the efficient reduction of nitrogen to ammonia. The effect of catalyst loading, temperature, and applied potential was tested on the nitrogen reduction reaction (NRR) using Pt and Ir catalysts in an electrochemical cell using an alkaline polymer gel electrolyte. It was hypothesized that the polymer gel electrolyte would limit the transport of water in the electrolyte and thus inhibit the competing HER. Pt and Ir nanoparticle electrocatalysts were synthesized and deposited on carbon gas diffusion electrodes. The ammonia was quantified by conversion to indophenol and testing via UV-Vis absorption spectroscopy. The generation of ammonia with both catalysts was demonstrated, and the reaction parameters tested were determined not to have a statistically significant impact on the results. While considering alternative catalysts for the NRR, it became clear that some contamination was contributing to false positive signals, thus a number of different possible sources of false positive signal were tested. Residual ammonia in the humidifier in the NRR reaction setup was quantified, and steps were taken in the experimental process to mitigate this issue. Degradation of the ionomer binding agent used in the electrodes was also tested, and deemed unlikely to be a contributor to the observed contamination. Finally, a series of blank tests were run which revealed intermittent ammonia contamination, which was attributed to ambient atmospheric ammonia contamination (open full item for complete abstract)

Committee: Gerardine Botte (Advisor); Valerie Young (Advisor); Savas Kaya (Committee Member); Howard Dewald (Committee Member); John Staser (Committee Member); Katherine Cimatu (Committee Member) Subjects: Chemical Engineering

Master of Science in Chemical Engineering, Cleveland State University, 2019, Washkewicz College of Engineering

As landfills approach capacity and take up valuable land space, metropolitan areas have realized the need for waste disposal alternatives. Thus, there has been a widespread use of waste incinerators in Europe and the United States [1]; [2]. Although newer technology has made incinerators more efficient, there is an increasing interest in formulating `greener' alternatives to incinerators. Gasification converts organic and carbonaceous materials into a combination of gaseous products known as “syngas,” or synthetic gas. This process greatly reduces the amount of hazardous emissions. The syngas produced by gasifiers has a wide range of uses, including their conversion into diesel, ethanol, methane, methanol and other synthetic fuels [3]. This research consists on an experimental assessment of Low-Temperature Wet Thermal Oxidation (WTO) [4] as a waste management alternative. Detailed experimental assessment and preliminary modeling of gasification technology to process polymeric waste into supply gas is completed here for a model polymer. While catalytic gasification of waste polymers has significance in a variety of engineering applications, it is of particular relevance to in-situ resource utilization (ISRU) and waste management in space exploration beyond low earth orbit (LEO). The substrates studied in our laboratory, Polyethylene and Cellulose, are both long chain organic polymers, and make up a substantial portion of both space and municipal waste composition. Although similar in nature, these substrates exhibit marked differences as it pertains to gasification and were therefore selected as model substrates. Experiments performed on polyethylene over a 5 wt% ruthenium catalyst supported by alumina are reported and analyzed in this paper. Analysis of gaseous products using a gas chromatograph with thermal conductivity detection provided data reflecting the conjunctive performance of all reactions. Application of reaction engineering parameter definit (open full item for complete abstract)

Committee: Jorge Gatica (Advisor); Christopher Wirth (Committee Member); Orhan Talu (Committee Member) Subjects: Chemical Engineering; Sustainability

Doctor of Philosophy, The Ohio State University, 2017, Chemical Engineering

Sustainability assessment and design is a multidisciplinary problem that cannot be addressed by methods developed in a single discipline. Sustainability being anthropocentric has until now been addressed mostly by techno-centric methods that usually offer incremental improvements. This approach can guarantee solutions that continuously outperform previously obtained solutions while also minimizing environmental impact, but it disregards ecological thresholds or the limits imposed by nature. Consequently, designing and engineering systems that overshoot nature's capacity has been one of the primary causes for ecological degradation, contradictory to the goal of sustainable development. To avoid such unintended outcomes and perverse solutions, methods for sustainability must adopt a holistic approach towards assessment and design. Ecological systems that support the functioning of human activities by providing essential goods and services must be explicitly considered during the assessment and design phases. Explicitly including the role played by ecological systems in supporting human activities will enable accounting for the dependence and impact of technology on nature and vice versa, and enable systems to operate within ecological constraints. This dissertation contributes to the effort of including nature in engineering decisions for sustainability by developing assessment techniques, design methods and building inventories that will help in decision making. The Techno-Ecological Synergy (TES) framework developed earlier provides a basis for explicitly including the role played by nature in supporting human activities by quantifying the demand and supply of ecosystem services. Ecosystem service demand is quantified by emissions and resource used, while supply is quantified by the capacity of nature to provide services. While originally developed as a sustainability metric, this framework provided the initial motivation for exploring the feasibility of d (open full item for complete abstract)

Committee: Bhavik Bakshi (Advisor); James Rathman (Committee Member); David Tomasko (Committee Member); Guy Ziv (Committee Member) Subjects: Chemical Engineering; Environmental Science; Sustainability

Doctor of Philosophy, The Ohio State University, 2015, Chemical Engineering

Design and assessment activities have traditionally been performed with respect to a relatively narrow analysis boundary and without accounting for influences from or on the world outside the boundary. This ``all other things being equal'' mindset results in tractable, generally solvable problems, but it precludes the detection of externalities, consequences that manifest outside the analysis boundary. From a sustainability perspective, externalities - whether they affect the environment, society, the economy, or other systems - cannot be ignored. Moreover, many externalities lead in turn to feedback effects, often negative, on the system of interest. Failing to account for these effects can result in decisions that appear economically, environmentally, or otherwise optimal within a narrow analysis boundary but are sub-optimal or simply incorrect when a larger perspective is taken. To anticipate externalities and avoid the unpleasant surprises they lead to, it is critical to use a holistic perspective for sustainable design and assessment. While this is not a novel concept, to date most efforts towards sustainable design and assessment have been made within single fields of study, including engineering, economic analysis and life cycle assessment. The models used within each discipline are well-suited to the traditional, narrow analysis boundary but frequently capture systems outside that boundary in a simplistic and even unrealistic fashion. This dissertation posits that for sustainability applications, a holistic perspective is best accomplished by combining modeling techniques and other methods from a variety of previously disparate disciplines. These various techniques each have shortcomings and advantages that are often complementary. Combining models from multiple disciplines thus offers an opportunity to create a widely applicable, integrated method with all of the advantages and relatively few of the shortcomings of each individual approach. This disse (open full item for complete abstract)

Committee: Bhavik Bakshi (Advisor); Liang-Shih Fan (Committee Member); James Rathman (Committee Member) Subjects: Chemical Engineering; Sustainability

Doctor of Philosophy, The Ohio State University, 2012, Chemical and Biomolecular Engineering

For any human-designed system to be sustainable, ecosystem services that support it must be readily available. This work explicitly accounts for this dependence by designing synergies between technological and ecological systems. The resulting techno-ecological synergy mimics nature at the systems level, can stay within ecological constraints, and can identify novel designs that are economically and environmentally attractive and may not be found by the traditional design focus on technological options. This approach is outlined from a general engineering perspective using several qualitative examples as well as through presenting general heuristics and potential applications, and then showcased by designing synergies for a typical American suburban home. Systems included in the design optimization include typical ecosystems in suburban yards: lawn, trees, water reservoirs, and a vegetable garden; technological systems: heating, air conditioning, faucets, solar panels, etc.; and behavioral variables: heating and cooling set points. The ecological and behavioral design variables are found to have a significant effect on the three objectives, in some cases rivaling and exceeding the effect of traditional technological options. These results indicate the importance and benefits of explicitly including ecosystems in the design of sustainable systems, something that is rarely done in existing methods. In addition to process design, the concept of techno-ecological synergy is applied to supply chain design, which is illustrated through two case studies: the optimization of the US transportation fuel portfolio, and a land use decision problem. Both cases studies illustrate how including ecosystem services can be done in supply chain management. These problems can be extended to more complex systems through the use of the presented input-output methodology. The second part of this work deals with the analysis of integrated techno-ecological systems. First, the ecologically- (open full item for complete abstract)

Committee: Bhavik Bakshi (Advisor); Jay Martin (Committee Member); James Rathman (Committee Member); Barbara Wyslouzil (Committee Member) Subjects: Alternative Energy; Chemical Engineering; Ecology; Sustainability; Systems Science

Master of Science in Engineering, Youngstown State University, 2024, Department of Civil/Environmental and Chemical Engineering

A longitudinal study in corrosion was performed on tensile-elongation dog-bones, created using 3D-printed stainless steel. The effects of exposure to an acidic environment were investigated regarding mass-loss, tensile and yield strength, modulus of elasticity, profilometry of pits and defects, and microscopy of fracture-sites. The SS316L specimens were manufactured using different print-directions, specifically overlapping unidirectional or rotated bidirectional for each layer by an additive manufacturing unit, the Mazak VC-500/5X AM HWD. The novel aspect of this research is focusing on the differences that the path the hot-wire, direct energy deposition, print-head has on its corrosion characteristics, as opposed to only focusing on the printing-parameters. The goal was to determine what printing-directions and methods were best for resisting corrosion. The research outlines the process of preparing samples for controlled weight-loss in HCl as well as the methods used to measure the mechanical properties. This allows for the results to be repeated if desired. Upon thoroughly reviewing the data and drawing connections where applicable, it was determined within the test samples that unidirectional print-directions yielded better mass-loss and mechanical attributes than bidirectional printing. It was found that some print directions, namely 90°, which is perpendicular to the printing door, performed notably better than other directions such as 0° or 45°.

Committee: Holly Martin PhD (Advisor); Pedro Cortes PhD (Committee Member); Bharat Yelamanchi PhD (Committee Member) Subjects: Chemical Engineering; Chemistry; Engineering; Experiments; Materials Science

Doctor of Philosophy, Case Western Reserve University, 2023, Chemical Engineering

The work of my Ph.D. thesis focuses on understanding the physical and electrochemical properties of deep eutectic solvents (DESs) and concentrated hydrogen bonded electrolytes (CoHBEs) through experiments concerning their use as electrolytes for redox flow batteries. My work aims to provide a fundamental understanding of how DES components govern bulk properties and double-layer structure with the ultimate goal of leveraging the gained knowledge to design new electrolytes for flow battery applications. Thesis Goals ● Bulk liquid properties: To determine how molecular structure and composition of DES components affect bulk macroscopic properties such as density, viscosity, and conductivity. ● Electrode-electrolyte interface: To develop a physical model of the voltage-dependent ion accumulation in DESs and CoHBES near the electrode and to identify surface species during the course of a redox reaction. ● Redox active organics: To study redox active organics as potential candidates for redox material in a CoHBE-based flow batteries. Chapter 3: In Chapter 3, we investigate the differential capacitance of choline chloride (ChCl) and ethylene glycol (EG) as a function of potential and composition using electrochemical impedance spectroscopy (EIS) on glassy carbon, Au, and Pt electrodes. We compared these results to glyceline (ChCl:glycerol, 1:2). The capacitance-potential curves on glassy carbon were best explained by the modified Gouy-Chapman model. We observe a dampened U-shape similar to dilute electrolytes. However, the presence of significant ionic and hydrogen bonding interactions in these electrolytes introduced ambiguity regarding the point of zero charge, where the capacitance weakly depended on potential. When using Au electrodes, we observe an increase in capacitance due to desolvation and specific adsorption of Cl ions. Conversely, with Pt electrodes, we observe increased capacitance with decreasing Cl concentrations. These results indicate that deep e (open full item for complete abstract)

Committee: Burcu Gurkan (Advisor); Clemens Burda (Committee Member); Robert Warburton (Committee Member); Robert Savinell (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2023, Electrical and Computer Engineering

Beta-phase gallium oxide (β-Ga2O3), with its ultrawide band gap energy (~4.8 eV), high predicted breakdown field strength (6-8 MV/cm), controllable n-type doping and availability of large area, melt-grown, differently oriented native substrates, has spurred substantial interest for future applications in power electronics and ultraviolet optoelectronics. The ability to support bandgap engineering by alloying with Al2O3 also extends β-(AlxGa1-x)2O3 based electronic and optoelectronic applications into new regime with even higher critical field strength that is currently unachievable from SiC-, GaN- or AlxGa1-xN- (for a large range of alloy compositions) based devices. However, the integration of β-(AlxGa1-x)2O3 alloys into prospective applications will largely depend on the epitaxial growth of high quality materials with high Al composition. This is considerably important as higher Al composition in β-(AlxGa1-x)2O3/Ga2O3 heterojunctions can gain advantages of its large conduction band offsets in order to simultaneously achieve maximized mobility and high carrier density in lateral devices through modulation doping. However, due to the relative immaturity of β-(AlxGa1-x)2O3 alloy system, knowledge of the synthesis and fundamental material properties such as the solubility limits, band gaps, band offsets as well as the structural defects and their influence on electrical characteristics is still very limited. Hence, this research aims to pursue a comprehensive investigation of synthesis of β-(AlxGa1-x)2O3 thin films via metal organic chemical vapor deposition (MOCVD) growth methods, building from the growth on mostly investigated (010) β-Ga2O3 substrate to other orientations such as (100), (001) and (-201), as well as exploring other polymorphs, such as alpha (α) and kappa (κ) phases of Ga2O3 and (AlxGa1-x)2O3 to provide a pathway for bandgap engineering of Ga2O3 using Al for high performance device applications. Using a wide range of material characterization techniqu (open full item for complete abstract)

Committee: Hongping Zhao (Advisor); Siddharth Rajan (Committee Member); Steven A. Ringel (Committee Member); Sanjay Krishna (Committee Member) Subjects: Condensed Matter Physics; Electrical Engineering; Engineering; Materials Science; Nanoscience; Nanotechnology; Physics

Doctor of Philosophy, Case Western Reserve University, 2023, Chemical Engineering

Membrane adsorbers are established tools in the field of bioprocessing and bioseparations that provide marked advantages over resin-packed columns. Translating this foundational knowledge from the field of membrane science to solve separations challenges in radiochemistry may provide similar advantages for on-column metals separations. This thesis takes the first steps towards bridging the gap between these two fields. It begins by reviewing basic experimental procedures and modeling required to fully characterize new membrane adsorber materials. It addresses the relationship between different membrane communities and ties together commonly used metrics in the fields of membrane science, environmental chemistry, and radiochemistry. Practical aspects of experiments are described including instrumentation for quantifying metals and their sample requirements such as types of species detected, detection range, lower detection limit, uncertainty, and sample volumes needed. The model system investigated in this thesis is motivated by the need to rapidly purify Cu-67, a theranostic radionuclide, from Ni contaminants. Such separations are typically performed in strong acids after dissolving the irradiated target. In this work, aminated polymer membranes were synthesized through activator generated by electron transfer, atom transfer radical polymerization (AGET ATRP). AGET ATRP is a controlled polymerization technique that was used to grow poly(glycidyl methacrylate) brushes from poly(vinylidene fluoride) membrane surfaces. Post-polymerization, an epoxide-ring-opening reaction occurred to attach the various amines (4-(aminomethyl)pyridine (AMP), ethylenediamine (EN), and putrescine (P)). The permeance of the synthesized membrane were measured with pure water flux experiments and ranged from 300 to 2650 LMH-bar-1. Removing residual catalytic copper from the AGET ATRP reaction is a key step in membrane manufacturing because it is considered a contaminant downstream. Thus, pro (open full item for complete abstract)

Committee: Christine Duval (Advisor); Lydia Kisley (Committee Member); Christopher Wirth (Committee Member); Donald Feke (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2022, Chemical Engineering

Drag reduction (DR) by additives typically involves the use of either high molecular weight polymer or surfactants, and can reduce turbulent pressure losses in pipes by up to 90%. These additives, particularly high polymers, have seen considerable use in increasing the throughput of crude oil pipelines. Surfactant additives, while even more effective than their polymer cousins, have not seen widespread adoption despite their applicability to recirculating district heating or cooling networks. Due to their effects on the turbulent structure of pipe flow, drag reducing additives also result in the loss of radial mixing, and thus the suppression of convective heat transfer. This is referred to as the 'heat transfer reduction' (HTR) effect. Under normal conditions, drag reducing additives can reduce convective heat transfer in even greater amounts than they do turbulent pressure losses. Much of the recent research in the field of surfactant drag reduction has, therefore, been dedicated to the mitigation of heat transfer reduction. In this work, two projects are presented which successfully achieve this goal. In the first, a constricted heat exchanger is used to locally increase the shear stresses experienced by the working fluid. Simultaneously, a `weak' drag reducing solution comprised of quaternary ammonium salts with saturated tails 16 and 14 carbons in length and the counterion 3-chlorobenzoic acid. In conjunction with the constricted heat exchanger, this mixture is able to simultaneously generate high (>60%) DR and low (>30%) HTR over a range of flow rates and temperatures. Other unique properties of the system are examined, including switchability and hysteresis. The second study involves the design and application of 'gentle' static mixers. Rather than being designed to destroy the micellar structure thought to be responsible for DR, these mixers are intended to periodically disrupt the thermal boundary layer in the heat exchanger, thus improving heat tr (open full item for complete abstract)

Committee: Kurt Koelling (Advisor); Jim Rathman (Committee Member); Stuart Cooper (Committee Member); Andrew Maxson (Committee Member) Subjects: Chemical Engineering; Energy; Engineering; Fluid Dynamics

Doctor of Philosophy (PhD), Ohio University, 2021, Chemical Engineering (Engineering and Technology)

Incorporation of potassium bifluoride (KF-HF) as an additive to lithium-halide electrolyte for thermal batteries was investigated. Results indicated that it is feasible to maintain a relatively high ionic conductivity at temperatures (250-300 C) lower than current thermal battery electrolytes (400-550 C). Mixtures of lithium fluoride and potassium bifluorides with the 40-60 wt.% provided the best ionic conductivity at 260 C. Ceramic felts are shown to be an effective alternative to widely used MgO. One of the major benefits of ceramic felts is their high porosity and low weight. LiSi/FeS2 thermal cells with YSZ and Al2O3 ceramic felt electrolyte/separators reported specific energy of 58.47 Wh kg-1 and 43.96 Wh kg-1. Pellet design pyrite (FeS2) cathodes for thermal batteries usually have low electronic conductivity. A new cathode design was developed using iron particles. By adding 11 wt.% Fe particles to the cathode the ohmic polarization was reduced by 17.5% while the available capacity was increased by 78% over the cell with traditional cathode pellet with no electrically conductive particle additives.

Committee: Gerardine Botte (Advisor); Valerie Young (Advisor) Subjects: Chemical Engineering; Energy; Engineering

Doctor of Philosophy, University of Akron, 2018, Polymer Science

Fossil energy from coal, gas, and oil-based fuel stocks remains a vital cornerstone of the global energy infrastructure while contributing over half of annual CO2 emissions. Rising global CO2 concentrations and aberrant trends in climate have sparked recent scrutiny of the energy industry sustainability. Carbon capture, utilization, and storage (CCUS) at the site of power plants has been proposed as a strategy for mitigating atmospheric CO2. This dissertation covers simulated and experimental models designed to address key problems in both the fundamental science and applied engineering of amine-functionalized silica sorbents for carbon capture from few molecule DFT (density functional theory) calculation to kilogram-scale technology validation. DFT was used to emulate small molecule and polymeric amines with good agreement in four successive series of models. (i) The concept of CO2 adsorption strength on secondary amines was investigated which revealed lone amine sites produce weakly adsorbed species while dense amine pairs yield strongly adsorbed species. (ii) Mixed amine types are common in blended or polymeric amine systems and convolute data interpretation. The hydrogen bonding ability of ammonium carbamate pairs demonstrated significant dependence on amine type and local hydrogen bond partners. (iii) Fixation of amines onto substrates is a ubiquitous strategy for preparing CO2 sorbents. The effect of geometric constraint imposed by immobilization was investigated for simulated propylamine pairs. Binding energy was linearly dependent on the alignment of ammonium carbamate. FTIR features were categorized into four groups. (iv) Selective formation of carbamic acid was studied by modeling reactants, intermediates, transition states (TS), and products of the amine-CO2 reaction on simulated diamine substrates. It was shown that significant reduction in TS activation energy occurred by Grotthus-like proton hopping. Coal-fire power plant CO2 capture was experime (open full item for complete abstract)

Committee: Steven Chuang (Advisor); Mesfin Tsige (Committee Chair); Tianbo Liu (Committee Member); Stephen Cheng (Committee Member); David Perry (Committee Member) Subjects: Chemical Engineering; Chemistry; Materials Science; Physical Chemistry; Polymers

Doctor of Philosophy, The Ohio State University, 1974, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1961, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1955, Chemical Engineering

N/A

Committee: Webster Kay (Advisor) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2015, Chemical Engineering

Our three studies examine the factors of learning styles, student self-efficacy, collective (team) efficacy, attitudes, perceptions, and performance at individual and team levels. Each study addresses a different environment: (i) Individual Level—we are interested in how variability in learning styles engaged by specific exam problems may correlate with student learning styles, self-efficacy, and performance in our introductory chemical engineering course, Process Fundamentals (i.e., mass and energy or material balances); (ii) Team Level—we are interested in understanding how team composition with respect to learning styles (homogeneous vs. heterogeneous teams) may influence these factors in the upper level Unit Operations course; (iii) Combinatorial Level—we are interested in understanding how collective efficacy may influence individual self-efficacy and again if there are any correlations with learning styles and performance in the senior level Process Design and Development course. Some of the most interesting results of these studies have stemmed from the study on individual students, which has shown correlations between learning style preferences and performance in specific instances. Even more interesting, evaluating and characterizing the learning styles that exam problems engage has shown strong variations in problem types by instructor. This presents new questions regarding how these variations may affect student understanding and subsequent performance. Also included are details regarding a course developed in Technical and Professional Communication (for Chemical Engineers) that was offered Spring 2014 and Spring 2015.

Committee: David Wood (Advisor); James Rathman (Committee Member); David Tomasko (Committee Member) Subjects: Chemical Engineering; Education

Doctor of Philosophy, The Ohio State University, 2015, Chemical and Biomolecular Engineering

The significant increase in the average global temperature has been determined to be the result of anthropogenic release of greenhouse gases, such as carbon dioxide, into the atmosphere. With this in mind, nations have considered a carbon tax for emission of carbon dioxide into the atmosphere from point sources, such as power plants. However, carbon capture from power plants has proven to be expensive both economically and in terms of energy penalty due to endergonic nature of molecular separation. A number of technologies have been developed, such as oxycombustion, and gasification combined cycle that are able to capture carbon. However, these technologies require a means of providing either providing pure oxygen to oxidize the fuel or a molecular means to separate the carbon dioxide from nitrogen, both of which have the potential to be prohibitively expensive, in terms of capital expense and parasitic load. Chemical looping combustion has been considered a transformational technology for simultaneous carbon capture and electricity generation. The technology consists of providing oxygen to the fuel using a metal oxide in one reactor, producing pure carbon dioxde as the product, and combusting the metal oxide in a separate reactor to produce heat for steam and electricity generation. This configuration has been extensively studied by researchers around the world in small-scale pilot units. Furthermore, the iron-based CDCL technology has been demonstrated at Ohio State in a 25-kWth subpilot unit with reasonable success, with high conversions of solid fuels such as sub-bituminous coal and waste products such as metallurgical coke fines. Furthermore, the carbon dioxide purity in the flue gas is around 99%, with low values of carbon monoxide, methane, and hydrogen impurities. As of this writing, over 680 hours of operation have been performed in this unit, with a successful 200 hour continuous campaign. Furthermore, extensive laboratory bench unit studies have been (open full item for complete abstract)

Committee: Liang-Shih Fan PhD (Advisor); W.S. Winston Ho PhD (Committee Member); Lisa Hall PhD (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2014, Chemical and Biomolecular Engineering

The growing demand for energy and concerns over greenhouse gas emissions are challenges that prompt innovative solutions to conventional energy generation technologies. The chemical looping processes developed at The Ohio State University (OSU) is an innovative technology that has the potential to efficiently generate electricity and/or high value chemicals from solid or gaseous fuels while capturing the CO2 produced. Chemical looping processes utilize oxygen carrier particles to indirectly convert the carbonaceous fuels while inherently capturing CO2 for sequestration and/or utilization. OSU has developed a unique moving-bed reactor design and an iron-based oxygen carrier particle. The counter-current moving-bed operation of the reducer enhances the extent of oxygen carrier conversion greatly reducing the solid circulation requirements compared to a fluidized bed reducer reactor design. As one of the process configurations OSU is developing, the syngas chemical looping (SCL) process for gaseous fuel conversion circulates the oxygen carrier particles through 3 reactors, the reducer, oxidizer, and combustor, to perform reduction-oxidation reaction cycles. Many metal oxides are used as the primary material in the oxygen carrier particle. Iron oxide is shown to have good reactivity, strength, temperature, and environmental characteristics over other the metal oxides considered. Further, when considering the thermodynamic properties of the metal oxide for H2 production in the case of chemical looping process for the direct H2 production, iron oxide provides the highest steam conversion to H2 compared the other metal oxides used in chemical looping. Additionally, the oxygen carrier resistance to contaminants in the fuel feed such as carbon deposition and sulfur is another important factor. Moving bed simulation studies indicate iron is also resistant to contamination from carbon and sulfur. Therefore, iron oxide is selected as the primary metal oxide for the oxygen carri (open full item for complete abstract)

Committee: Liang-Shih Fan PhD (Advisor); Winston Ho PhD (Committee Member); David Wood PhD (Committee Member); Lei Bao PhD (Committee Member) Subjects: Chemical Engineering