Doctor of Philosophy, The Ohio State University, 2024, Electrical and Computer Engineering

Contactless, nondestructive measurements of minority carrier lifetime by transient microwave reflectance (TMR) and photoluminescence are used to study the carrier dynamics of several ternary materials: InGaAs, GaAsSb, and InAsSb. As contactless measurements, TMR and photoluminescence can determine quality of as-grown wafers. The minority carrier lifetime is inversely proportional to the diffusion component of the dark current and can be used as an indicator of device performance, without the need for full device fabrication. The ability to yield useful information about wafer quality without the time and cost used for fabrication allows for quick feedback to growers. GaAsSb and InGaAs lattice-matched to InP are candidates for short-wave infrared (SWIR) detection at 1.5 μm, a wavelength used for eye safety and optical communication. The high speed or low signal applications at this wavelength benefit from the use of separate absorber, charge, and multiplier (SACM) avalanche photodiodes (APDs). In these devices, the absorber is optimized for detection at the wavelength of interest, and the multiplier is optimized for gain through impact ionization. InGaAs-based SACM APDs are a mature technology and are available commercially. The multipliers paired with InGaAs, however, typically have high noise. Research into low-noise multipliers has resulted in the demonstration of AlGaAsSb as a low noise material. When AlGaAsSb is paired with InGaAs, the grading material AlInGaAs creates a conduction band offset with AlGaAsSb, limiting bandwidth. GaAsSb lattice-matched to InP has similar properties to InGaAs and could be implemented without a conduction band offset due to the grading material being AlGaAsSb. When a GaAsSb/AlGaAsSb SACM APD was demonstrated, it was found to have higher dark current than commercial InGaAs-based devices. Because these materials are so similar, this was unexpected. As mentioned, the diffusion component of the dark current is inversely proportio (open full item for complete abstract)

Committee: Sanjay Krishna (Advisor); Steve Ringel (Committee Member); Preston Webster (Committee Member); Anant Agarwal (Committee Member); Shamsul Arafin (Committee Member) Subjects: Electrical Engineering

Master of Science (MS), Ohio University, 2024, Mechanical Engineering (Engineering and Technology)

In recent years, lithium-ion batteries (LIBs) have played an essential role in nowadays energy storage system, especially electric vehicles (EVs) and portable electronics because of its high energy density and long cycle life [1, 2]. However, one of the biggest challenges is how to guarantee their dependability and trustworthiness. In the present investigation, Acoustic Emission (AE) and Ultrasound Testing (UT) techniques are systematically employed to verify probable critical defects in the LIBs. Where AE technology is able to record the stress waves produced by the growth of the defects, UT uses high-frequency sound waves to penetrate the batteries and provide an indication of the internal voids. The performances of these approaches were systematically tested on as-received, pre-damaged and cold-soaked batteries. Different AE and UT activity patterns were shown in the results under various environmental conditions that influenced battery performance. Combining Acoustic Emission (AE) and Ultrasound Testing (UT) with clustering and outlier analysis machine learning algorithms improved defect detection effectiveness. Such research highlights that AE and UT can be robust noninvasive techniques for on-line health monitoring of LIBs that should aid in maintaining the longevity and operability of LIBs.

Committee: Brian Wisner (Advisor) Subjects: Acoustics; Mechanical Engineering

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

Simulations of materials are a cost-efcient way to study materials that aid in experimental planning and material design. For example, stress and plasticity analysis is readily performed by numerically-based simulations, like fnite element or spectral based methods, and are typically faster than performing the experiment itself. However, slow computation times of more complex simulations limit their use in the design space. Deep learning (DL) networks have been shown to be orders of magnitude faster than numerically-based simulations but are lacking in numerical accuracy by comparison. Furthermore, large datasets are required to train a DL network and collecting a sufcient amount is a difcult task in materials science. Incorporating physical laws of the material system within the DL model has been shown to create a more physically accurate network, but can be difcult to implement. In this thesis, DL networks are physically informed through the data, network architecture, or loss function to create a model that accurately refects the underlying physics of the material system. First, a network is proposed to study the feasibility of 3D grain reconstruction from mid-feld high energy difraction refections. Each refection corresponds to its own subnetwork, tailoring the weights to a specifc refection. In a diferent network, a U-Net is used to simulate the micromechanical evolution of a 3D polycrystal at small strain increments and predict the full-feld orientation and elastic strain. The network is physically informed about the Von Mises stress relationship from the predicted elastic strain tensors. The training requirements of networks having physics-informed characteristics are studied in more depth using stress feld prediction as a case study. A Pix2Pix model is used to translate a two-phase composite having high elastic contrast to the corresponding stress fields. Several diferent physics-based regularization methods are implemented to enforce stress equilibrium in t (open full item for complete abstract)

Committee: Stephen Niezgoda (Advisor); Dennis Dimiduk (Committee Member); Reeju Pokharel (Committee Member); Aeriel Leonard (Committee Member); Michael Groeber (Committee Member) Subjects: Materials Science

Master of Science, The Ohio State University, 2024, Chemistry

With sustainable energy storage at the forefront of global concerns, the development of high-performance, long-lasting battery systems is of paramount importance. The first chapter of this thesis explores polymerization techniques for synthesizing tetrazine-based polymers as sustainable cathode materials for aqueous Zn-ion batteries. Understanding the impact of polymerization on tetrazine electrode materials has interesting implications for the overall adoption of the tetrazine motif in energy storage. The second chapter of this thesis investigates the incorporation of nitrogen oxide gases in Na batteries. The incorporation of these gases promises to surpass cell potentials and reversibility seen in conventional Na-O2 or Na-CO2 batteries. By harnessing the unique properties of nitrogen oxides, this research aims to markedly enhance battery energy output, contributing to the advancement of sustainable energy technologies.

Committee: Yiying Wu (Committee Member); Shiyu Zhang (Advisor) Subjects: Chemical Engineering; Chemistry; Energy

Doctor of Philosophy in Engineering, Cleveland State University, 2022, Washkewicz College of Engineering

Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In order to reach amorphization, magnetic alloys are traditionally melted and then cooled down very fast to prevent crystallization and grain growth in their microstructure. However, there are several disadvantages associated with this method of fabrication, such as the limitation in thickness of the products. To solve this issue, we proposed a new method of fabrication for magnetic alloys where amorphization occurs through mechanical alloying, and the amorphous powder alloy that is produced by this process is then consolidated using a technique called spark plasma sintering finding appropriate mechanical alloying processing parameters to get an amorphous structure. Many different processing parameters were investigated, and the mechanical properties, microstructure, and magnetic properties of all samples were examined. The effect of spark plasma sintering processing parameters on samples sintered from the amorphous powders was then studied. Finally, the amount of energy introduced to the powder from the milling balls during the mechanical alloying process was calculated. We were able to find a trend between the energy introduced to the powder during the milling process and the amorphous structure of the milled powders. From our data, we draw an energy map that shows the window (open full item for complete abstract)

Committee: Tushar Borkar (Advisor); Majid Rashidi (Committee Member); Somnath Chattopadhyay (Committee Member); Maryam Younessi Sinaki (Committee Member); Petru Fodor (Committee Member) Subjects: Engineering; Materials Science; Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2022, Chemistry

Covalent organic frameworks (COFs) are an emerging class of crystalline porous organic polymers composed of light elements (C, H, N, O, and B) connected through strong covalent bonds. The design and syntheses of COFs primarily relies on the principles of dynamic covalent chemistry in conjunction with non-covalent interactions. COF structures are often accessed via the utilization of reversible bond-forming reactions under reaction conditions that promote this reversibility to achieve porous, ordered materials that can be characterized as having high surface areas, permanent porosities, low densities, and high chemical and thermal stabilities. One of the prominent advantages of COFs is their modular nature. Through reticular chemistry, careful structure design, and choice of building units can allow for the fabrication of materials suited for specific applications. These principles have been employed to tune the stability, crystallinity, and properties of different materials.COFs also possess a high degree of π-conjugation and are insoluble in most common organic solvents. These attractive assets have made COFs of great interest in a range of applications and fields including chemical sensing, energy storage, catalysis, and gas capture and storage. This research will focus on the design of COFs for use as organic anode materials in potassium ion batteries as well as the investigation of their thermal conductivities. There is currently growing interest in the development of organic electrode materials for energy storage devices due to their sustainability and low costs. Currently, the industry standard anode material is graphite, a material that has yet to reach its theoretical potential. In efforts to synthesize a layered material with properties similar to the carbon allotrope, graphyne, two alkynyl-containing COFs were investigated as potential organic anode materials in potassium ion batteries; TAEB-COF and DBA-COF 3. After 300 cycles at a current density of (open full item for complete abstract)

Committee: Psaras McGrier (Advisor); Jovica Badjic (Committee Member); Jon Parquette (Committee Member) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 2022, Chemistry

Highly concentrated electrolytes exhibit advantages in enhanced stability, low solvent volatility and superior battery safety. It is, therefore, important to design salts that push the limit of solubility. A solvent-in-anion design of potassium salts is proposed, in which a solvent moiety is grafted onto a symmetric anion to form a new asymmetric anion possessing the structural features of the solvent. Guided by the like-dissolves-like rule, the resultant new salts exhibit record high solubilities. I have demonstrated this concept by grafting ether-solvent-moieties onto trifluoromethylsulfonamide (TFSA) to form potassium asymmetric salts. The solubility in dimethylethane (DME) reaches an unprecedent concentration of a mole fraction of 0.6. The resultant concentrated electrolyte improves the cycle life of potassium-oxygen batteries with reduced overpotentials. Moreover, single crystal X-ray diffraction of these salts reveals a rich variety of coordination motifs with coordination number ranging from 5-8 and extensive multidentate and bridging interactions from all the possible coordinating atoms on the anion. Our solvent-in-anion design represents a new approach that utilizes crystal structures to probe the solvation structures in liquid, and the revealed rich variety of solvation structures are of use to the experimental and theoretical modelling of concentrated electrolytes. Developing low melting alkali salts is of interest for both battery electrolytes and inorganic ionic liquids. I have synthesized a series of asymmetric alkali metal sulfonamide salts based upon the (3-methoxypropyl)((trifluoromethyl)sulfonyl) amide (MPSA) anion. This family of salts features an unusual melting point trend, where the melting point of the salts decreases as the cation increases in size from Li to K, but then the melting point increases as the cation further increases in size from K to Cs. Exceptionally, KMPSA, features a very low melting point of only 50.79±0.31°C. Analyses of (open full item for complete abstract)

Committee: Yiying Wu (Advisor); Wolfgang Windl (Committee Member); Anne Co (Committee Member); Patrick Woodward (Committee Member) Subjects: Chemistry

PhD, University of Cincinnati, 2022, Arts and Sciences: History

“Fernald and the Transformation of Environmental Activism” explores the grassroots environmental movement in Fernald, Ohio, that forced the Department of Energy (DOE) to transform its nuclear weapons production complex in the 1980s and 1990s. Built in the early 1950s, the Feed Materials Production Center, better known as Fernald, produced high purity uranium metals, or “feed materials,” for the federal government's plutonium production reactors in Hanford, Washington, and Savannah River, South Carolina. After a series of uranium leaks in 1984, the plant's closest neighbors organized as Fernald Residents for Environmental Safety and Health (FRESH) to hold the DOE accountable for contaminating the community. FRESH joined Fernald's unionized production workers in the Fernald Atomic Trades and Labor Council (FATLC) to challenge the DOE on grounds of environmental health and safety. This alliance attracted important political allies, including Ohio Senator John Glenn, whose efforts attracted national attention to Fernald. This dissertation argues that Fernald's locally focused, nationally connected, and multi-class movement of housewives and workers represents a new brand of environmental activism that protected nuclear weapons production workers and communities from the dangerous byproducts of the Cold War nuclear arms race.

Committee: David Stradling Ph.D. (Committee Member); Tracy Teslow Ph.D. (Committee Member); Drew Swanson Ph.D. (Committee Member); Jason Krupar Ph.D. (Committee Member) Subjects: American History

Doctor of Philosophy (Ph.D.), University of Dayton, 2022, Electrical and Computer Engineering

In this dissertation, Fresnel coefficients are examined for electromagnetic (EM) propagation across an achiral/chiral (ACC) boundary, and thereafter extended to cases involving slab-type resonator structures. An important factor to be noted is that while the numerical results presented in this research are accurate to the limits of our assumptions, one feature of a chiral material not taken into consideration in the early stages of work is the presence of dielectric losses. It turns out that a chiral (meta) material is usually also lossy via a complex dielectric permittivity. In the research presented in several chapters of this dissertation, the chiral dielectric has been assumed to be lossless, whereby all three material parameters (permittivity, permeability and chirality) are assumed to be real. Towards the latter chapters, dielectric losses are taken into account to make the results more compatible with practical cases. The results presented are aimed at observing the effects of loss on both the propagated fields themselves as decaying vectors, as well as on the amplitude and phase characteristics of the relevant Fresnel coefficients (amplitude as well as power or intensity). As is well known, upon both transmission and reflection from a chiral interface, the incident plane (specifically perpendicularly or s-polarized) wave transforms into two modes (right circular polarization (RCP) and left circular polarization (LCP)), propagating non-collinearly and collinearly for the transmitted and reflected modes respectively. This work focuses on certain anomalous properties pertinent to the chirality itself which provide novel insights into chiral materials. The dissertation highlights anomalies relative to the emergence of Brewster effects, tunability of Brewster angles and critical angles via the (dimensionless) chirality coefficient (κ ) over specific bands, total internal reflection (TIR), non-complementarity, mode evanescence, and also possible effective ne (open full item for complete abstract)

Committee: Monish Chatterjee (Advisor); Partha Banerjee (Committee Member); John Loomis (Committee Member); Youssef Raffoul (Committee Member) Subjects: Electrical Engineering; Electromagnetics; Energy; Materials Science; Optics

Doctor of Philosophy, University of Akron, 2021, Mechanical Engineering

Nowadays, the automotive industry is paying more attention to autonomous vehicles; as a result, the importance of tire safety is increased. Since tires are the only contact between the vehicle and the road, monitoring the parameters such as tire pressure and temperature, friction between tire and road, and tire wear is essential to ensure vehicle safety. These parameters are monitored with the sensors embedded in intelligent tires. These sensors need electric power for operation. To provide the electric power for the intelligent tire sensors, piezoelectric energy harvesters (PEHs) can be used to harvest a part of tire deflection waste energy to provide electric power to the sensors. Two new shapes of piezoelectric energy harvester inspired from Cymbal piezoelectric energy harvester were designed. It has been proven that the Cymbal piezoelectric energy harvester is effective in vibration energy harvesting. Two new shapes are inspired by cymbal energy harvester, and they are developed to harvest strain energy from rolling tires. It is the first time this type of energy harvester based on the Cymbal geometry is used for the intelligent tire application. To ensure that these new designs will be safely and effectively embedded on the inner surface of tires, some modification on the shape, size, and design was made. The output voltage, power, and energy of the designed PEHs were evaluated through the developed Multiphysics model and experimental analysis. In order to run the experimental analysis, a wireless measurement system is developed. The PEH will be undergoing cyclic loading in the tire application. Therefore, the fatigue failure of the piezoelectric material is also considered in the design stage. The PEH is designed to be used in autonomous vehicles tire to provide power to the tire sensors. Due to this application, the PEH is subjected to temperature change, tire inflation changes, vehicle speed changes, and tire load changes due to this application. Therefore (open full item for complete abstract)

Committee: Siamak Farhad (Committee Chair); Truyen Van Nguyen (Committee Member); Ping Yi (Committee Member); Chen Ling (Committee Member); Gopal Nadkarni (Committee Member) Subjects: Mechanical Engineering

MS, University of Cincinnati, 2021, Engineering and Applied Science: Mechanical Engineering

In effort to both save operating expenses and be environmentally friendly, thermal energy storage provides a means for companies to handle daytime HVAC requirements while using off-peak (nighttime) electrical power. This paper sets out to compare three of the most common techniques used for thermal energy storage, by comparing both the analytical modeling of their energy storage and actual experimental data for their energy storage, using the same exact test apparatus for each of the techniques. The results of this experiment show that using normal HVAC temperatures, sensible water chilled to its maximum value after only about two hours, while PCM would take nearly six hours to achieve “linkage,” or solidified material merging between the helix coils. Ice building, done with -7° coolant, took 4.5 hours to achieve linkage. Initial heat transfer was proportional to the difference between initial tank temperature and the coolant temperature, and went asymptotically towards zero for sensible as the temperature of the tank and coolant reach equilibrium. For ice, the heat transfer rate was always more than twice that of PCM during latent storage, which is attributed to the difference between coolant temperatures and freezing points for the respective materials. Sensible water cooldown would require 232.8% of the tank volume to store the same energy relative to the environment compared to ice building, and 126.3% of the tank volume compared to phase change material. This is to be weighed with the benefit of using existing HVAC condensing units to chill the water, and the fact that water itself is inexpensive. The high latent heat of freezing for water meant it held more energy than both the water sensible cooldown and PCM freezing, but with the downside of requiring medium temperature condenser units in order to be efficient (instead of the high temperature units used in typical HVAC). After 4.5 hours, PCM would surpass the energy stored in the same volume as water sensi (open full item for complete abstract)

Committee: Michael Kazmierczak Ph.D. (Committee Chair); Ahmed Elgafy Ph.D. (Committee Member); Sang Young Son Ph.D. (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy, University of Akron, 2021, Polymer Engineering

This thesis research investigated material solutions for removal of emulsified water droplets from ultralow sulfur diesel (ULSD) fuel and for energy efficient crosslinking of tire tread compounds. Emulsified water droplets in ULSD fuel reduces combustion efficiency and causes corrosion of engine components. In view of the above, separation of water droplets from ULSD fuel lines is critical. In this research, high surface area aerogels produced from polyimide and syndiotactic polystyrene (sPS) were supported by load bearing, 3D-printed polymer constructs. The resultant constructs were used in removal of water droplets from ULSD via a combination of demulsification and size exclusion processes. The specific interactions of the surfactants with polymer surfaces and total surface area of the polymers were used as factors in determining water droplet removal efficiency. The study also evaluated the effectiveness of surfactant-free Pickering emulsion-templating process for incorporation of a large volume fraction of micrometer size voids (macrovoids) in the aerogel structures to obtain higher porosities than was possible with monolithic aerogels. Hydrophobic silica particles localized at the interfaces of water droplets were used to stabilize the emulsions of water in sPS solution in toluene. The thermo-reversible gelation of sPS chains locked the morphology and spatial distribution of water droplets within the gel. In the second part of the work, novel compounds based on benzocyclobutene (BCB) were developed and used along with conventional sulfur compounds for crosslinking of tire tread compounds. BCB underwent crosslinking reactions via ring-opening polymerization at temperatures > 220℃; but substituted BCB as used in this work exhibited crosslinking temperatures as low as 110℃;. Polymeric as well as small molecule BCB compounds were used in curing of rubber. Polymeric BCB compounds showed a 10-15% reduction in crosslinking time and a 10% increase in the crosslink de (open full item for complete abstract)

Committee: Sadhan Jana (Advisor); Kevin Cavicchi (Committee Chair); Fardin Khabaz (Committee Member); Hunter King (Committee Member); George Chase (Committee Member) Subjects: Polymer Chemistry; Polymers

Doctor of Philosophy in Materials Science and Engineering, Youngstown State University, 2020, Department of Mechanical, Industrial and Manufacturing Engineering

Functionally graded materials (FGMs) show promise in solving a number of design challenges, but there are challenges associated with their fabrication. Advances in additive manufacturing (AM) have improved the ability to produce FGMs, creating more opportunities for their use. In this study, additive techniques were used to create four types of FGM system in order test their suitability as armor materials against small arms projectiles: M300/316L, bronze-infiltrated 420S/A356, PH17-4/A356, and Tethonite/A356. Two methods were used in the fabrication of these FGMs: directed energy deposition (DED) for the compositionally graded M300/316L system, and hybrid printing and casting method to create gyroid-based mesostructural FGMs for the remaining systems. These FGMs were subjected to ballistic testing and their performance, measured in depth of penetration, was compared to monolithic materials. Additionally, finite element analysis (FEA) of the ballistic protection of these FGMs was presented and compared to experimental results. Poor agreement was found between model and experiment for the compositionally graded M300/316L and mesostructural tethonite/A356 systems, highlighting the need for accurate material models, but the PH17-4/A356 model found good agreement with experimental outcome. Among the FGM systems tested, the PH17-4/A356 mesostructural system showed the most promise, being able to deflect the projectile as it passed though the plate.

Committee: Jason Walker Ph.D. (Advisor); Brett Conner Ph.D. (Committee Member); Pedro Cortes Ph.D. (Committee Member); Stefan Moldovan Ph.D. (Committee Member); C. Virgil Solomon Ph.D. (Committee Member) Subjects: Engineering; Materials Science

MS, University of Cincinnati, 2020, Engineering and Applied Science: Materials Science

Energy consumption of the world is increasing rapidly, but nearly two-thirds of energy consumed is being wasted in the form of heat. Thermoelectric materials convert waste heat into electricity which can be used to improve the efficiency of existing systems and reduce the energy consumption. Currently most of the thermoelectric materials are inorganic semiconductors that are expensive, heavy, non-flexible and not scalable in production. They also suffer from lower efficiencies because their thermoelectric properties that together determine the efficiency are mutually coupled, i.e. increasing one factor negatively effects the other property. This has been one of the major factors limiting their success at the market level for decades. Recently, introduction of nanotechnology into bulk thermoelectric materials has shown promising results to improve their properties. Exploring possible organic materials as replacements for inorganic semiconductor materials has also given a new hope for improving the thermoelectric performances with advantages such as light weight, low cost and scalability for future energy applications. Decoupling of the thermoelectric properties may be possible by dispersing nanomaterials such as carbon nanotubes (CNTs) in organic material matrix. In this work, we dispersed single-walled CNTs in non-conducting polydimethylsiloxane (PDMS) elastomer matrix to create a versatile flexible thermoelectric material. PDMS was chosen as the matrix because of its many advantages such as its scalability, solution processability, low cost, light weight, high flexibility, biocompatibility and low thermal conductivity. PDMS is originally insulating, but by dispersing CNTs in it, percolation networks can be created to achieve a high electrical conductivity, which is required for high thermoelectric performance. Single-walled carbon nanotubes are chosen as conducting media because of their excellent electrical and thermal properties as well as easy dispersion in (open full item for complete abstract)

Committee: Je-Hyeong Bahk Ph.D. (Committee Chair); Mark Schulz Ph.D. (Committee Member); Donglu Shi Ph.D. (Committee Member) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2018, Materials Science and Engineering

The ultimate performance of functional materials and devices is critically dependent on micro-to-nanoscale features in related material systems. Structural defects, for example, such as stacking faults and misfit dislocations can hinder device (photovoltaics (PV), light emitting diodes, sensors etc.) efficiency significantly, but the exact mechanisms behind such behaviors remain elusive. Given this dependency, it is of utmost importance to study such features to understand their final role in device efficiency and to better understand the growth conditions that promote their existence. Electron microscopy is one of the few tools able to probe materials systems, both with respect to structure and properties, on these small length scales. The work presented here covers the detailed characterization and analysis of functional materials and structures, with primary focus on PV materials, using two techniques: (1) electron channeling contrast imaging (ECCI) for the rapid structural characterization of subsurface defects and features and (2) electron energy-loss spectroscopy (EELS) for the electronic characterization of various interfaces, chemical inhomogeneities, and structural defects of significance. ECCI work will highlight three new characterization applications of the technique: interfacial characterization, subsurface quantum dots, and chemical inhomogeneities. Additionally ECCI performed with scanning deep-level transient spectroscopy is demonstrated to show correlation between trap states and structural defects. EELS results will include the development of a new, robust method for nanoscale bandgap profiling and the novel demonstration of spatial- and energy-resolved EELS-based detection and characterization of sub-gap defect states. The objective of this research is the elucidation of the fundamental structure-property relationships within these materials systems, providing vital feedback into ongoing and future materials and device design, synthesis, and tes (open full item for complete abstract)

Committee: Tyler Grassman (Advisor); David McComb (Advisor); Maryam Ghazisaeidi (Committee Member); Stephen Niezgoda (Committee Member) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2018, Chemistry

Porous materials are an ever-expanding area of materials science well known for their highly porous structures, which are well suited to hosting a variety of guests from small compounds such as gasses to large complex molecules. Additionally, porous materials can be rationally designed prior to synthesis to incorporate monomers with desired functionalities, which makes them amenable to a variety of applications including gas storage and uptake, sensing, catalysis, and optoelectronics. Our interest has been to bring functional monomers, such as dye molecules, into porous polymers for applications geared toward alternative energy. One class of dye we found intriguing were subphthalocyanines (SubPcs), which have an unusual 3-dimensional shape and excellent optoelectronic properties. SubPcs are often incorporated into organic photovoltaics in the small molecule form, and have achieved good power conversion efficiencies up to 7%. We envisioned that incorporation of a SubPc into a polymer might have useful function in an optoelectronic application. We synthesized a boronate ester linked SubPc-based polymer, fully characterized its structure and tested its ability in optoelectronic applications. The boronate ester linkage has been a mainstay in the field of porous polymers, especially covalent organic frameworks (COFs). Despite its success in the early development of COFs, the boronate ester linkage suffers from a significant drawback of instability to small amounts of water. The field of COFs has been shifting away from the boronate ester linkage in favor of more chemically stable linkages that can still afford crystalline materials. One such linkage has been developed in our laboratory, the benzobisoxazole (BBO) linkage. We have shown the BBO linkage yields crystalline materials with good stability in water. However since the BBO linkage is a relatively new development in the field of COFs not much is known about how this linkage promotes crystallinity in COF mat (open full item for complete abstract)

Committee: Psaras McGrier (Advisor); Jovica Badjic (Committee Member); Jon Parquette (Committee Member) Subjects: Chemistry; Materials Science; Polymers

Master of Science in Mechanical Engineering, Cleveland State University, 2018, Washkewicz College of Engineering

In metallurgy, Titanium has been a staple for biomedical purposes. Its low toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between Titanium alloys (116 GPa) and human bone (40-60 GPa) contribute to long term issues with loose hardware fixation. Additionally, long term studies have shown elements such as Vanadium and Aluminum, which are commonly used in Ti-6Al-4V biomedical alloys, have been linked to neurodegenerative diseases like Alzheimers and Parkinsons. Alternative metals known to be less toxic are being explored as replacements for alloying elements in Titanium alloys. This research will focus on advanced processing and characterization of beta-phase Titanium alloys for biomedical applications. The microstructure, mechanical and electrochemical properties of these alloys have been analyzed and compared with C.P. Titanium. The main objective is to study the effect of different alloying elements on microstructure, phase transformation and mechanical properties of these newly developed beta-phase Titanium alloys and establish new avenues for the future development of biocompatible Titanium alloys with optimum microstructure and properties.

Committee: Tushar Borkar Ph.D (Committee Chair); Taysir Nayfeh Ph.D (Committee Member); Jason Halloran Ph.D (Committee Member) Subjects: Biomedical Research; Design; Materials Science; Mechanical Engineering

Doctor of Philosophy, Miami University, 2015, Chemistry and Biochemistry

This dissertation describes five unique projects which advance spectroscopy in terms of education, technology and applications. Project goals were designed so the end results would assist with solving educational, military and industrial challenges through the use of spectroscopy. These goals were accomplished through the use of new, existing and adaptations of existing spectroscopic instrumentation. New spectroscopic instruments were developed and built for use in educational teaching laboratories at Miami University. These instruments included a low-cost Raman spectrograph and a low-cost flame atomic emission spectrometer. Both instruments have economic and educational benefits over commercial instruments and the flame emission instrument has already demonstrated its value in the classroom. The next project, driven by military interest, involved using near-infrared diffuse reflectance spectroscopy for the standoff detection of explosive materials on common surfaces. Projects included coating substrates with high energy materials and acquiring spectra from those coated substrates. Results showed differences in the detection limits for ammonium nitrate on various substrates, and these limits were directly dependent on the characteristics of the substrate. Another project was completed in collaboration with the United States Food and Drug Administration's Forensic Chemistry Center. This project's goal was to identify counterfeit goods based on their packaging materials. By taking a cross section of a packaging material and acquiring a high resolution attenuated total internal reflection (ATR) Fourier transform infrared (FTIR) image, differences could be revealed which showed variances between the authentic and counterfeit packaging materials. Finally, an adaptation of an ATR-FTIR microscope was used in an attempt to improve the spatial resolution of an ATR-FTIR image by working in a non-contact type sampling configuration. Improvements in spatial resolution have n (open full item for complete abstract)

Committee: Andre Sommer (Advisor); Neil Danielson (Committee Chair); Jonathan Scaffidi (Committee Member); Tom Cambron (Committee Member); Paul Urayama (Committee Member) Subjects: Chemistry

MS, University of Cincinnati, 2011, Engineering and Applied Science: Civil Engineering

Building systems may achieve an integration of affordability, green construction, and sustainability through the utilization of straw-bale construction. This building method may be particularly beneficial to countries that are characterized by developing economies or are enduring a recovery from a natural disaster. Employed as a means to replace or complement traditional building materials, straw-bale construction provides easy installation and energy efficiency. Conventional and prescriptive building regulations create a barrier to the widespread advancement of straw-bale construction. Specifically, common and standardized materials exist in capital intensive industries that compete against each other in a market that can support testing. These factors provide difficulty in introducing and establishing new and competitive building materials. Similarly, preconceived notions of straw-bale construction methodology, design limitations, and supposed deficiencies in straw bales as a feasible building material must be overcome. The exploratory study undertaken herein developed an evaluation of those factors that are impeding the development of this construction methodology in North America. The goal of the study is to provide an analysis of what is the general consensus from builders, contractors, engineers, and architects regarding straw-bale construction. The primary research methods included surveying building professionals throughout North America to gauge their perceptions and experiences. Furthermore, a Life Cycle Assessment (LCA) was conducted to measure the environmental impact of a straw-bale home as compared to a home utilizing common building techniques. Such results may be utilized to facilitate the advancement of this affordable and sustainable construction material.

Committee: Bahram Shahrooz PhD (Committee Chair); Lilit Yeghiazarian PhD (Committee Member); Hazem Elzarka PhD (Committee Member); Margaret Kupferle PhDPE (Committee Member) Subjects: Civil Engineering

PhD, University of Cincinnati, 2010, Engineering : Materials Science

This dissertation presents an analysis of innovation in engineering materials and energy sources. More than fifty engineering materials and fourteen energy sources were selected for an evaluation of the relationship between the yearly production activity and yearly patent counts, which may be considered as a measure of innovation, for each. Through the employment of correlation theory, best-fit and origin shift analyses, it has been determined here that engineering materials and energy sources display similar life cycle and innovative activity behaviors. Correlation theory revealed a relationship between the yearly production and yearly patent counts indicating the extent that production and innovation affect each other. Best-fit analysis determined that four-stage life cycles exist for both engineering materials (metals and non-metals) and energy sources. Correlation and best-fit indicators of an estimated Stage III are confirmed by the presence of an origin shift of the patent data when compared to the production data which indicates that patents, or innovation, are driving, or being driven by, production. This driving force could represent the constructive or destructive side of the innovative process, with such sides being delineated by a possible universal constant above which there is destructive innovative behavior and below which exists constructive innovation. The driving force may also illustrate the manner in which an engineering material or energy source transitions into an innovatively less active state, enter Stage IV and possibly become a commodity. A possible Stage V, indicating “Final Death”, is introduced in which production is on a steep decline with no signs of recovery. Additionally, innovatively active energy sources are often found to utilize or be supported by innovatively active engineering materials. A model is presented that can be used for the evaluation of innovation and production that can be applied to both engineering materials and en (open full item for complete abstract)

Committee: Jainagesh Sekhar PhD (Committee Chair); Ronald Huston PhD (Committee Member); Steven Benintendi PhD (Committee Member); Jude Iroh PhD (Committee Member); Rodney Roseman PhD (Committee Member) Subjects: Materials Science