Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2021, Materials Science and Engineering

A metallic network has been embedded in a silicon carbide fiber– silicon carbide (SiC) matrix ceramic composite (CMC) in order to combine the functional properties of the metal and the structural properties of the CMC. The processing of the composite involves iterative pre-ceramic polymer infiltration and heating to temperatures at 1100°C. The metallic structure embedded in the CMC must retain its unique properties during processing and cannot convert to a silicide or carbide resulting from diffusion of Si and C species from the SiC matrix. To gain an understanding of the diffusion process, a fully processed CMC with tungsten, tantalum, and molybdenum wires will be heated at various temperatures for the same duration. The diffusion zone will be measured and then kinetics equations will be applied to determine the failure kinetics. Understanding the diffusion kinetics and phases formed at higher temperature can provide a processing path which avoids metal degradation.

Committee: Hong Huang Ph.D. (Advisor); Joy Gockel Ph.D. (Committee Member); Zlatomir Apostolov Ph.D. (Committee Member) Subjects: Materials Science

Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2020, Materials Science and Engineering

Lithium-ion batteries are part of a multibillion-dollar industry that strives to meet the demands for an increasingly advanced technological future. Flexible batteries can be easily adapted from emerging novel wearable electronics to electrical vehicles and advanced solar panels. Solid-state batteries can greatly reduce the risk of fire or leaking hazardous materials due to puncture. For the development of solid-state flexible lithium based batteries polymer-ceramic composites are attractive electrolyte candidates because of their combined properties, such as electrical, thermal and mechanical properties, that not only overcome limitations from the base materials but may also render some enhanced performances resulting from the interaction among the components. In this study polymer-ceramic composite electrolytes consisting of polyethylene oxide (PEO), Li1.4Al0.4Ge1.6(PO4)3 (LAGP) and two lithium salts (LiTFSI and LiBF4) are studied. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Dynamic Mechanical Analysis (DMA) are used to characterize their thermal and mechanical characteristics. The glass transition temperature, onset of melting, the decomposition temperature, the characteristics of the stiffness and strength as a function of temperature are determined and analyzed. It is aimed to determine how the lithium salts and LAGP ceramic impact the thermal and mechanical properties of the electrolytes.

Committee: Hong Huang Ph.D. (Advisor); Henry Young Ph.D. (Committee Member); Michael Rottmayer Ph.D. (Committee Member) Subjects: Materials Science; Mechanical Engineering

MARCH, University of Cincinnati, 2017, Design, Architecture, Art and Planning: Architecture

Vacancy has long been a struggle in the United States due to the cycle of urbanization and suburbanization. There has continuously been a large number of vacant properties across the country, and higher vacancy rates lead to increased rates of demolition. An increase in demolished structures, in turn, leads to a higher volume of waste entering the country's landfills. Cincinnati is one of the many cities with a surge in re-urbanization. While redevelopment has quickly spread through the city's derelict neighborhoods, many vacant properties still stand, and their futures are often uncertain. This thesis looks at an obsolete, vacant structure in Cincinnati's downtown neighborhood, and proposes an alternative method of recycling to reduce the building industry's waste production through repurposing building rubble and salvaged materials into dry ingredients for architectural ceramic clay bodies. The recycled clay is then translated into traditional and contemporary architectural ceramics that work together to form a designed spatial showcase of CERAMIC ARCHITECTURE. The program, a youth recreational facility, is intended to highlight the forgotten and unconventional applications of ceramics as a construction medium. Within each program space, ceramic becomes more than just a traditional finish material, but acts as both finish and architectural element [structure, partition, acoustic treatment, etc.] simultaneously.

Committee: Aarati Kanekar Ph.D. (Committee Chair); Katie Parker (Committee Member) Subjects: Architecture

Doctor of Philosophy, The Ohio State University, 1970, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2016, Materials Science and Engineering

SiC/SiC ceramic matrix composites (CMCs) with potential applications at =2700°F (1482°C) are of significant interest to the Air Force. The high temperature performance of SiC fibers used within these composites is greatly affected by the presence of amorphous SiOC and free carbon in the fibers. Therefore quantification of this non SiC material in commercially available SiC fibers is extremely important. In this work Hi Nicalon, Hi-Nicalon Type-S, Tyranno-SA3, Cef-NITE, and Sylramic SiC fibers were studied. Changes in mass, grain size, and amorphous content were measured as a function of processing temperature and time. The amorphous material in each fiber was quantified using the Spike-In method in conjunction with Rietveld refinement. Trends in amorphous content were observed, as well as trends in grain size and crystallized fraction. Transmission electron microscopy (TEM) was used to confirm changes in fiber microstructure.

Committee: H. Daniel Young Ph.D. (Advisor); Hong Huang Ph.D. (Committee Member); Michael Cinibulk Ph.D. (Committee Member); Robert E. W. Fyffe Ph.D. (Other) Subjects: Aerospace Materials; Materials Science

MFA, Kent State University, 2016, College of the Arts / School of Art

My thesis presents a series of pieces that transferred from the basic, natural form to be tougher, stronger, and abstract. These pieces are meant to present the idea of abstraction that inspired by my life, and embodied on these organic forms from the ocean. The idea of my work presents the changes that happened to me and reflect into my work. How I challenged myself to adjust no matter what happened during the period of my study abroad. Also, how I used these challenges, and life experiences as an inspiration.

Committee: PETER JOHNSON (Advisor); JANICE LESSMAN (Committee Member); ISABEL FARNSWORTH (Committee Member); GIANNA COMMITO (Committee Member) Subjects: Fine Arts

Master of Science in Engineering, University of Akron, 2010, Chemical Engineering

Nitrogen Oxide (NO) and carbon monoxide (CO) are major pollutants in the exhaust streams of automobiles, power plants, and other combustion processes. The growing concerns for the environment have resulted in increasingly restrictive emission standards. The removal of NO and CO from exhaust gases is a challenging task. One method for harmful gas removal is using a catalyst for dissociation. This work explored an alternative method for catalytic reduction of NO. Polymer solutions with palladium catalyst and ceramic precursors were electrospun to form polymer nanofibers. These nanofibers were heated to form ceramic nanofibers with catalyst nanoparticles and were mixed with microfibers to form a nonwoven fibrous catalyst support structure. The concentration of the polymer was varied to create nanofibers with diameters ranging from 100 to 700 nm with a constant mass of catalyst particles per mass of fiber. The effect of the fiber diameter on the corresponding catalyst structure performance was tested. A surface area comparison test was completed to determine whether the reactions occur strictly on the surface of the catalyst or if diffusion occurs. An aging comparison was also completed which tested 1 week old catalytic filters compared to 6 months old. A conventional catalytic converter was tested to verify the performance was similar to the catalytic fibrous filter media containing only palladium. Experiments were carried out using a lab reactor to expose the media to a mixture of gases simulating an exhaust stream at room temperature to a maximum of 450°C. The reactor exhaust concentrations are measured using gas chromatography (GC) to determine the catalyst performance. Results indicated that the catalytic reaction performance was about the same for fiber sizes ranging from 100 to 700 nm on a mass basis with a reduction temperature of 325 – 350°C. The surface area comparison filter reduced at 275°C which showed that both surface catalyst particles and particles w (open full item for complete abstract)

Committee: George Chase Dr. (Advisor) Subjects: Chemical Engineering

Master of Science, The Ohio State University, 1950, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Arts, The Ohio State University, 1969, Graduate School

Committee: Not Provided (Other) Subjects:

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

For CMCs with an electrically conductive matrix, direct current potential drop techniques have the potential to detect composite state such as conductive constituent content (e.g., Si in melt infiltrated composites) or local defects such as delamination or porosity. Melt-infiltrated SiC based composites are an ideal candidate material for such to verify this since the Si content of the matrix is the primary current carrier in the system. In our study, we aimed to evaluate the effectiveness of Electrical Re-sistance (ER) as a NDE method for different 2D woven SiC-based Melt-infiltrated composites, each exhibiting varying degrees and types of processing defects. We con-ducted four types of ER measurements: a. Bulk Resistivity b. Through-thickness c. Axial d. Surface, along the length of the dogbone specimens in the gauge section and on a large plate. Microstructural analysis was performed to correlate observations with microstructure. The bulk resistivity of the specimens in our study exhibited a linear correlation with the infiltrated Si content of the matrix even with different percentage and type of porosities present, allowing us to comment on Si-content of the speci-mens. The Through-thickness set-up incorporates current leads to supply current in a through-thickness manner and determine the nature of current spreading (voltage drop) some distance   away from the current source. The absolute values of the measured through thickness potential represent Si-content, but it is unresponsive for processing defects. The axial set-up is more conventional and can generate local axial current flow. In some cases, such flow of current is affected by and able to locate the local and distinct type porosi-ty. Resistance was sensitive for regions of poor Si-infiltration i.e., “dry-slurry” type defects as well as for isolated larger rounded porosity. It was very sensitive to local surface porosity but not as sensitive for cases where porosity was homogenously pre-sent throug (open full item for complete abstract)

Committee: Dr. Gregory N Morscher (Advisor); Dr. Wiesław K Binienda (Committee Member); Dr. Siamak Farhad (Committee Member); Dr. Jun Ye (Committee Member); Dr. Manigandan Kannan (Committee Member) Subjects: Mechanical Engineering

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

Ceramic matrix composites (CMC) are candidate high-temperature materials for gas turbine engines. GTE components that could utilize CMCs include exhaust diffusers, combustor shrouds, and turbine blades and vanes (1, 2). However, current gas path temperatures are high enough that superalloy metals and even CMCs require cooling air drawn from the compressor for turbomachinery that is immediately downstream of the combustor. This cooling air will subject those blade and vane interior cooling passages and cooling holes to intermediate temperature air at a water vapor partial pressure near 1 atm. Specimens from a Hi-Nicalon Type S/BN/SiC (MI) composite with multiple machined holes were subjected to a furnace dwell and then tensile tested at room temperature. The furnace temperature range was 500°C-1100°C and the atmosphere was pure steam. Pure steam at 1 atmosphere approximated the sea level partial pressure of water vapor in the cooling air going through turbomachinery cooling holes. Exposure of control specimens was done in laboratory air at the same temperatures as the steam furnace specimens. Data included tensile results along with digital image correlation, computed tomography, microscopy, and spectroscopy results. The hole array was analytically modeled to predict its resulting stress concentration factor; test results showed that the hole array caused a lower stress concentration factor than analytical modeling predicted. There was significant strength degradation in some conditions due primarily to oxidation of the boron nitride fiber coating, with coating volatilization at lower temperatures and probable fiber to matrix bonding and imposed fiber stresses at higher temperatures. The greatest strength degradation occurred in the 500°C-600°C steam range. The fiber coating oxidation/volatilization was especially evident near the holes and was exacerbated in the lower temperature tests by porosity networks from composite processing that were open (open full item for complete abstract)

Committee: Ronald Kerans (Committee Chair); Charles Browning (Committee Member); Craig Przybyla (Committee Member); Li Cao (Committee Member); George Jefferson (Committee Member); James Larsen (Committee Member) Subjects: Materials Science

Master of Fine Arts, The Ohio State University, 2024, Art

In the image of me delicately placing the scholar rock I had created on a meticulously crafted Victorian-influenced base, I perceive a vivid reflection of the narrative of my newly forged life after my immigration to the United States. Delving into the memories of my father's cherished pastime of curating a collection of scholar rocks, I discern a striking parallel between this artistic amalgamation and my own odyssey from the Eastern shores to the Western lands, signifying not just the initiation of a fresh chapter, but a profound process of uprooting, assimilation, and harmonious fusion. In a manner akin to how my father, with his knee, would nudge and coax a scholar rock to carefully situate it on a bespoke base made of a distinctive wood, meticulously considering hues and patterns, and then took care to ensure the picturesque and stable positioning of the base and rock in the gentle currents of a narrow riverbed, I gently place a scholar rock of molded and fired clay on each ceramic Victorian base I make. And just as my father's actions would elevate the presence and worth of each scholar rock he manipulated and displayed, I hope that my creative act of making and combining the Eastern-influenced ceramic rock with the western, Victorian-inspired base, elevates the essence of my personal journey from East to West.

Committee: Steven Thurston (Advisor); Todd Slaughter (Committee Member); Carmel Buckley (Committee Member) Subjects: Fine Arts

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

High temperature materials such as Ceramic matrix composites (CMCs) have grown more and more popular for aerospace applications due to their superior strength to weight ratio and enhanced damage tolerance when compared to super alloy and monolithic ceramic materials. However, there are notable challenges when it comes to their successful implementation of these materials in hot-section aero-engine components, primarily stemming from their susceptibility to severe damage caused by solid particle erosion due to repeated particle impacts. Although extensive efforts have been dedicated in understanding erosion in CMCs, the majority of this research has been conducted under standard ambient conditions. Given the elevated temperature environments in which CMCs will ultimately operate, it becomes crucial to comprehend how high-temperature conditions impact the lifespan of CMCs subjected to high velocity particle impacts. Therefore, the primary focus of this research is on evaluating what parameters affect erosion behavior of oxide and non-oxide CMC at temperatures of 800°C and 1200°C with different velocity of 200m/s and 350m/s, respectively. On a different note, CMCs are prone to significant strength degradation upon material removal resulting from the repeated or cumulative impingement of solid particles. While erosion in ceramics and composites has been extensively studied, existing research may not be directly applicable to strength degradation caused due to repeated particle impacts on CMCs due to their more complex architecture and failure mechanisms at different operating temperatures. Therefore, second objective of this work is to investigate relationship between high temperature erosion behavior and strength degradation in several non-oxide and oxide-based CMCs and to evaluate erosion response caused by solid particle impacts under stress induced conditions involving fatigue and creep loading.

Committee: Gregory Morscher (Advisor); Simak Farhad (Committee Member); Manigandan Kannan (Committee Member); Craig Menzemer (Other); Jun Ye (Committee Member); Sergio D. Felicelli (Committee Chair); Qixin Zhou (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2024, Materials Science and Engineering

Nanoparticles have amassed significant interest in recent decades due in part to size-tunable properties and seemingly endless relevance towards a variety of applications. As a result, several synthesis studies on nanoparticle nucleation and growth have emerged, achieving tight control through tunable size and morphology. However, incorporation of such reactive, high surface energy nanoparticles into various engineered media is challenging as these materials are particularly prone to aggregation and surface reactions. And often, for direct application into biomedical devices, battery electrodes, displays, ceramic matrix composites, etc., nanoparticle dispersion into matrix materials for composite development is necessary. Moving forward, more research needs to be devoted to nanocomposite formulation where control over nanoparticle shape, size, dispersion, and properties is maintained throughout mixing into various media. This dissertation highlights three approaches to understanding or enhancing nanoparticle control during nanocomposite development. In the first, a Si-based polymer-derived ceramic nanocomposite is developed in which copper nanofillers are added to a polysiloxane matrix. The composite is taken through various stages of processing into a polymer-derived ceramic. At discrete temperatures, high energy X-ray scattering for pair distribution functions is collected to monitor structural changes in the matrix, ripening of the nanofiller, and local structure interactions occurring between the nanofiller and matrix material. High resolution techniques such as synchrotron X-ray scattering and pair distribution functions have sparingly been applied to the field of PDC nanocomposites. The simultaneous resolution of local scale bonding moieties in the matrix and interactions on the nanoparticle surface throughout processing help establish understanding of nanoscale changes in PDC nanocomposites that has been lacking in the field thus far. For polymer-derived (open full item for complete abstract)

Committee: Sheikh Akbar PhD (Advisor); Michael Mills PhD (Committee Member); Roberto Myers PhD (Committee Member) Subjects: Materials Science

Doctor of Philosophy (Ph.D.), University of Dayton, 2023, Electrical Engineering

Lithium-ion batteries (LIBs) have transformed modern electronics and rapidly advancing electric vehicles (EVs) due to high energy, power, cycle-life, and acceptable safety. However, the comprehensive commercialization of EVs necessitates the invention of LIBs with much enhanced and stable electrochemical performances, including higher energy/power density, cycle-life, and operation safety but at a lower cost. An unprotected lithium-ion battery (LIB) cell cathode using lithium metal anode and organic carbonate liquid electrolyte undergoes significant structural damage during the cycling (Li+ intercalation/ deintercalation) process. Also, a bare cathode in contact with a liquid electrolyte forms a resistive cathode electrolyte interface (CEI) layer. Both the cathode structure damage and CEI lead to rapid capacity fade. Different strategies have been used to mitigate the degradation of LIB electrodes, including designing electrolytes to enhance SEI/CEI formation, cycle stability, interface engineering with protective coatings to prevent the breakdown of active material particles during cycling, composition control of the electrode particles, synthetic optimization to control particle morphology, the use of composites made from conductive scaffolds and active materials and designing new electrode architectures to overcome volume changes and enhance transport properties. Cathode surface modification has been used to reduce CEI formation and structural damage, improving capacity retention, cycle life, energy density, power density, and safety of a LIB. Recently, the coating of the cathode with an intermediate layer (IL), which is transparent to Li+ conduction but impermeable to electrolyte solvent, has been developed to minimize CEI formation and structural damage. IL based on Li+ insulating ceramics, such as aluminum oxide (Al2O3), tin oxide (SnO2), and magnesium oxide (MgO), has been developed but to limited success in mitigating the above cathode degradation. The (open full item for complete abstract)

Committee: Dr. Jitendra Kumar (Committee Chair); Dr. Guru Subramanyam (Committee Member); Dr. Feng Ye (Committee Member); Dr. Vikram Kuppa (Committee Member) Subjects: Electrical Engineering; Energy; Engineering