Doctor of Philosophy, The Ohio State University, 2023, Food Science and Technology

Consumer demands for ethically sourced and environmentally friendly food products have led to development efforts to replace animal-based proteins with plant-based alternatives. However, plant-based protein ingredients can be limited by their functional and sensory properties, and thus processing techniques to improve these properties must be explored. Enzymatic hydrolysis has been suggested to improve key functional properties, such as solubility, but the research methodology in this area is questionable and hydrolysis does not fully address sensory deficits in plant-protein ingredients, notably bitterness. In this dissertation, commercial extruded snack products containing soy protein hydrolysates were used as a model to quantify bitterness and test the viability of reformulation with flavor maskers or alternatively processed proteins to improve off-flavor. This study revealed that commercial flavor maskers are not effective at reducing bitterness in products containing soy hydrolysate, but soy protein hydrolysates made by different manufacturers with different processing methods proved a viable replacement with improved off-flavor. In search for conclusive evidence that enzymatic hydrolysis results in improved functionality, a review of literature was conducted. This review concluded that enzymatic hydrolysis process may result in the formation of insoluble aggregates, which in most studies are removed by centrifugation or filtration during processing, thus artificially increasing the reported solubility values for plant-protein hydrolysates. The phenomenon of hydrolysis induced aggregation was confirmed for protein isolates from soy and as well as a pulse protein alternative to soy, chickpea, which were hydrolyzed by Flavourzyme and Alcalase. Analysis of physical and structural properties of the hydrolyzed proteins revealed that hydrolysis led to protein destabilization, causing hydrogen-bond mediated aggregation during thermal enzyme inactivation. The knowledge (open full item for complete abstract)

Committee: Farnaz Maleky (Advisor); Osvaldo Campanella (Committee Member); Emmanuel Hatzakis (Committee Member); John Litchfield (Committee Member); Lynn Knipe (Committee Member) Subjects: Biochemistry; Food Science

Doctor of Philosophy (PhD), Ohio University, 2022, Chemistry and Biochemistry (Arts and Sciences)

Antibiotic resistance is a global threat beside the ongoing pandemic by SARS-CoV-2. The number of deaths due to antibiotic-resistant infections is increasing at an alarming rate. The COVID-19 pandemic has already claimed millions of deaths worldwide. Fighting against antibiotic-resistant superbugs and the SARS-CoV-2 has become a challenge. A significant amount of research is going on to develop the vaccine and small molecule antiviral and antibacterial therapeutics targeting proteins. Fortunately, novel non-coding regulatory RNA targets have been identified for developing new antibacterial and antiviral drugs such as bacterial T-box riboswitch, RNA thermometers, and viral stem-loop II motif. T-box riboswitch can control the transcription or translation of amino acid-related genes in bacteria by forming unique interactions between tRNA and mRNA. RNA thermometers (RNATs) are temperature-responsive riboswitches that control the translation based on temperature sensing thus controlling the interaction with the mRNA and 16S rRNA. In Shigella dysenteriae, three RNATs, i.e., ompA, shuT, and shuA, have been discovered. ompA RNAT controls the translation of outer membrane protein A. shuT, and shuA RNAT controls the translation of two proteins that are crucial to the bacterial heme utilization system. The Stem-loop II motif (S2M) is a highly conserved RNA element found in most coronaviruses, astroviruses, and picornaviruses that plays a potential role in viral replication and invasion. The RNA structure plays a significant role in its regulatory function for all of these potential therapeutic targets. Consequently, it is essential to examine the factors that affect the RNA structure and RNA-RNA interaction. Despite having limited building blocks, RNA has diverse functions in the cells. Base protonation and protonated base pairs often occur in RNA when interacting with other biomolecules, thus could play a critical role in vital biological processes. Diff (open full item for complete abstract)

Committee: Jennifer Hines (Advisor) Subjects: Biochemistry; Biology; Genetics

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

The rapid advancements in the development of small unmanned aerial systems (sUAS) and their availability allow various inspection and construction surveying businesses to implement them in their daily functions reasonably and economically. These systems give users access to a wide range of low altitudes, high resolution and geo-referenced visual and thermal image datasets that were not easily available in the past. This research uses available sUAS systems, visual and thermal cameras, and photogrammetry software to develop standard operating procedures, using the best practices found through experimentation, to augment monitoring and inspection of infrastructure health and construction sites. The purpose of this research is to document the applications of sUAS to augment infrastructure and construction site inspection process and ensure that the generated outputs can be easily perceived and replicated by trained engineers and professionals in their respective surveying fields. This research work details the development of flight planning, image capture, 3D/2D outputs processing, and post-processing procedures to aid in the inspection of facilities, bridges, and construction sites. The research process used off-the-shelf unmanned aerial systems, cameras and photogrammetry tools to develop procedures that would generate accurate results. The research work involved learning and applying mixed scientific disciplines that included but not limited to aerospace engineering, image processing, civil engineering and systems engineering. First, the various photogrammetry software and hardware are discussed. Second, the workflow designed and the breakdown of the workflow to produce the desired outputs using photogrammetry tools are presented. This includes the research work conducted to study the effects of these parameters on the outputs produced. Third, the results obtained using the iii workflow is presented in the form of case studies. The study include (open full item for complete abstract)

Committee: Arthur Helmicki Ph.D. (Committee Chair); Richard Beck Ph.D. (Committee Member); Victor Hunt Ph.D. (Committee Member) Subjects: Electrical Engineering

Master of Science, University of Toledo, 2019, Civil Engineering

This thesis analytically investigates the effects of thermal loading on the aluminum overhead sign structure and calculates the remaining fatigue life of the structure. Overhead sign structures are widely used across freeways and highways to support traffic signals and signposts and monitor the proper ow of traffic. The Ohio Department of Transportation (ODOT) is responsible for the inspection and safe operation of the overhead sign structures in Ohio. However, sudden failure of an overhead sign structure on Alum Creek Drive in Columbus, Ohio, lead ODOT to initiate an investigation to determine the cause of failure. From the study done by a research team from the University of Toledo, Ohio, it was concluded that the failure was fatigue failure. Fatigue failure occurs due to the repetitive cyclic load acting on the structure. The cyclic loading can be thermal loading, wind loading, wind galloping and so on. This research concentrates on the effects of thermal loading on the structure and mainly illustrates about the fatigue stresses that are generated by the daily temperature variations and calculation of the fatigue life of the overhead sign structure due to these stresses. The research was done by creating an analytical model (based on the standard drawing provided by ODOT) of the structure using finite element software SAP2000, so that it resembled the structure that was erected in the field. Cyclic loading due to daily temperature variations was considered. The data of the daily temperature change were obtained from the National Climatic Data Center (NCDC) and a temperature histogram was plotted. These temperature variations were applied to the structure as thermal loads and corresponding thermal stresses were generated. Finally, using the Palmgren-Miner's rule, the fatigue life of the structure was calculated. This calculation of fatigue life assumed that the welded joints were in sound condition and there were no structural defects in the structure. Th (open full item for complete abstract)

Committee: Douglas K. Nims (Advisor); Eddie Y. Chou (Committee Member); Alex Spivak (Committee Member) Subjects: Civil Engineering

Doctor of Philosophy, Case Western Reserve University, 2019, Materials Science and Engineering

This research explores intrinsic properties of the carbon-rich subsurface zone (“case”) that low-temperature carburization generates in AISI-316 austenitic stainless steel. Foils of this steel were carburized to obtain concentrated interstitially dissolved carbon distributed uniformly throughout their thickness. Compared to the as-received AISI-316 foils, such “full” carburization increases the ultimate tensile strength to 3 times, the yield strength to 4 times, and Young's modulus to 1.5 times, respectively. On the other hand, the strain to failure decreases to (9 ± 1) 10^(-3). For comparison, foils with larger thickness were carburized as well. Decreasing the ratio of “case” to foil thickness was found to decrease the ultimate tensile strength, yield strength, and Young's modulus, while increasing the strain to failure. This research also investigates the impact of concentrated interstitial carbon on electrical conductivity, thermal conductivity, and conduction electron density and mobility. Foils with uniform carbon levels exhibit room-temperature electrical and thermal conductivity corresponding to only 0.8 and 0.7 times those measured in the as-received state, respectively. Hall-effect measurements revealed that concentrated interstitial carbon does not significantly reduce conduction electron mobility, but decreases the electron density to 0.7 of what we measured for as-received material. These observations suggest that the interstitial carbon atoms form covalent bonds with the metal atoms. With their unique combination of properties, free-standing uniform concentrated solid solutions of interstitial carbon in austenite can be regarded as a new material. Besides, this research also explores the thermal stability of the “case” at elevated temperature. Between 1300-1400 K, carbide transformation from M_{23}C_6 to M_7C_3 was observed. Finally, this research introduces a potential biomedical application of “case” on the Co–Cr–Mo alloy for surface wear improvement. (open full item for complete abstract)

Committee: Frank Ernst (Committee Chair); John Lewandowski (Committee Member); William Baeslack (Committee Member); Sunniva Collins (Committee Member) Subjects: Materials Science; Mechanical Engineering; Metallurgy

Doctor of Philosophy, Case Western Reserve University, 2019, EMC - Mechanical Engineering

Intumescent coating is becoming popular in building constructions as a passive fire protection product. It expands and forms a porous thermal protective char layer when exposed to a fire and can effectively protect building steel structures from high temperature. A large number of studies about intumescent coatings have been conducted, particularly in the following fields: (1) chemical formulation, which focuses on the choices of ingredients; i.e., a carbon source, an acid source and a blowing agent, to form a proper combination; and (2) numerical models, which aim to simulate the chemical-reaction and heat-transfer processes during the fire protection period. To develop a new formulation and additives or to validate the numerical models, the characterization of the char formation is of essential importance. However, a universal characterization method has not yet been fully developed for diagnosing the internal char-forming processes, the morphological structure of the char formed, and the real-time interior thermal properties during the fire protection period. This deficiency stems mainly from technical difficulties in obtaining structure character from the expanded char without damage and measuring a precise heat transfer history from a high temperature (up to 600 ℃ ) shape changing porous media. In this study, a laboratory-scale mass-loss cone heating device is used to impose three incident radiant heat fluxes (25, 50, and 75 kW/m2) on different types of intumescent coatings (water-based and epoxy-based). The morphological characteristics of the expanded and charred intumescent coatings have been studied using a computer tomography (CT)-based analysis method. Image processing techniques are applied to the CT-scanned data to generate 3D reconstructed images and to measure structure properties using ImageJ software. Thermal insulating performance (apparent thermal conductivity and heat blocking efficiency) of the expanding char layer is determined in situ based o (open full item for complete abstract)

Committee: Fumiaki Takahashi Professor (Committee Chair); James Tien Professor (Committee Co-Chair); Ya-Ting Liao Professor (Committee Member); Gary Wnek Professor (Committee Member) Subjects: Engineering; Industrial Engineering; Mechanical Engineering

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

Hydrogels are water-swollen polymer networks that often exhibit biocompatibility and mechanical properties similar to many natural tissues. These properties grant hydrogels biomedical applications, such as tissue engineering, wound dressing and drug delivery. In recent years, supramolecular hydrogels with reversible, non-covalent crosslinks have received attention by researchers because of their toughness and the ability to be molded into complex shapes by conventional polymer processing techniques. During deformation, the reversible crosslinks (hydrophobic associations, ionic bonds, and/or hydrogen bondings) will dissociate and re-form to dissipate mechanical energy and prevent failure. In order to design tough supramolecular hydrogels, it is important to understand their structure-property relationships, i.e., the effect of crosslink structural change on the mechanical/rheological properties of hydrogels. This work investigated physically crosslinked hydrogels composed of random copolymers with hydrophilic segments [N,N-dimethylacrylamide (DMA) or 2-hydroxyethyl acrylate (HEA)] and hydrophobic segments [2-(N-ethylperfluorooctane sulfonamido)ethyl acrylate/methacrylate (FOSA or FOSM)]. When swollen in water, these copolymers form networks by the hydrophobic aggregation of FOSA/FOSM segments into nanodomains. The nanostructure of these hydrogels was elucidated by small angle neutron scattering (SANS) with contrast variation. The in-situ nanostructure evolution of the hydrogels during deformation and relaxation was monitored by small angle X-ray scattering (SAXS) and correlated with the mechanical properties of the hydrogels. During uniaxial extension, the rearrangement of crosslinks altered the network conformation and resulted in a non-affine deformation. With increasing strain rate, more rearrangement of crosslinks occurred to dissipate mechanical energy and toughen the hydrogel. At the same time, more structural anisotropy occurred due to less network relaxati (open full item for complete abstract)

Committee: Bryan Vogt (Advisor); Robert Weiss (Advisor); Abraham Joy (Committee Member); Mark Soucek (Committee Chair); Qixin Zhou (Committee Member) Subjects: Polymer Chemistry; Polymers

Doctor of Philosophy, University of Akron, 2017, Polymer Science

Geckos are intriguing creatures, adhering to ceilings, to leafs, to glass and cement, all without glue. Instead, their adhesion is dependent on surface interactions between their hierarchical adhesive structure and the contacting substrates. These interactions on the nanoscale have significant macroscale influences. Changing the conditions between substrate and the nanostructures of the gecko adhesive affects the ability of geckos to adhere. Improving our understanding of how these conditions affect the adhesion of the natural gecko system can then inform our synthetic adhesive design efforts. Here, I have investigated how geckos perform on 'soft' substrates and on rough underwater substrates. Taking inspiration from the hierarchical nanostructure of the gecko adhesive, and its interactions with water, hierarchical rough carbon nanotube substrates were used to investigate the roles of roughness and surface chemistry on superhydrophobic stability. The 3D structure of CNTs was further used to investigate the influence of surface interactions on the macroscale thermal conductivity properties.

Committee: Ali Dhinojwala Dr. (Advisor); Yu Zhu Dr. (Committee Chair); Gary Hamed Dr. (Committee Member); Mesfin Tsige Dr. (Committee Member); Peter Niewiarowski Dr. (Committee Member) Subjects: Condensation; Experiments; Nanoscience; Physics; Polymers; Zoology

Doctor of Philosophy, University of Akron, 2015, Polymer Science

Although single crystal X-ray diffraction remains the most important technique for analyzing periodically ordered structures at atomic resolution, single crystal X-ray diffraction of organic macromolecules is challenged by difficulty in growing single crystals of desired size and quality. Electron crystallography of organic macromolecules, on the other hand, is limited by image resolution due to radiation damage and highly dependent on high-resolution instrumentation. Novel alkylated benzothiophene derivatives synthesized previously can be readily fabricated into semiconductor devices for various applications (photodetectors, explosive sensors, field-effect transistors, light-emitting diodes, etc.) via solution process. The object of this research is to identify phase transitions of organic macromolecules of this kind via differential scanning calorimetry and temperature-resolved wide angle X-ray diffraction, and to determine their lattice parameters and space groups by reconstruction of their reciprocal space via transmission electron microscopy / selected area electron diffraction followed by refinement with X-ray diffraction, supplemented by polarized light microscopy. Computer simulation was performed to rationalize the molecular packing schemes, so as to understand the origin of their electronic performance from crystallographic perspective.

Committee: Stephen Z. D. Cheng Dr. (Advisor); Yu Zhu Dr. (Committee Chair); Toshikazu Miyoshi Dr. (Committee Member); Tianbo Liu Dr. (Committee Member); Xiong Gong Dr. (Committee Member) Subjects: Chemistry; Condensed Matter Physics; Materials Science; Organic Chemistry; Physical Chemistry; Physics; Polymers; Solid State Physics

Master of Science (MS), Ohio University, 2015, Geological Sciences (Arts and Sciences)

The Mohave Wash fault (MWF), a low angle normal fault (~2 km of slip) initiated near the brittle-ductile transition in crystalline rocks, is associated with the regionally developed Chemehuevi detachment system. To address the role of water on initiation and early slip, δ18O of quartz/epidote pairs from thin shear zones and vein-fill were analyzed in situ using a 10 µm ion microprobe spot (precision ±0.3‰, 2 SD). 480 analyses were made on 317 grains in 23 samples collected from three vertical transects from the footwall and through the damage zone, distributed over 17 km down-dip. Quartz from undeformed hosts defines pre-faulting δ18O = 9.0–10.4‰ VSMOW. δ18O values decrease within damage zone microstructures down to -1.0‰ for quartz and -5.3‰ for epidote. Such low-δ18O values at the structurally deepest exposures are interpreted to reflect influx of surface-derived fluids to depths of > 10 km. Syn- and post-deformation mineralization in ~25% of the shear zones record heterogeneous δ18O(mineral) on the scale of < 100 mm2. Inter- and intra-crystalline variability in δ18O is greatest in the damage zone. Host clasts are often preserved, but textural relations also signify heterogeneity in new mineral growth within discrete shear zones. Of 123 grains analyzed with multiple spots, 36% are zoned in δ18O; single-grain gradients reach 8.7‰ (over 500 µm) for quartz and 2.1‰ (over 300 µm) for epidote. Differences in Δ18O(Qtz-Ep) from adjacent rims over < 100 mm2 range from 0.2–8.0‰ (in damage zone) and 0.6–2.2‰ (below damage zone). Large variability in measured Δ18O(Qtz-Ep) is consistent with variable oxygen isotope exchange, and sub mm-scale heterogeneities in permeability. Despite the intrasample-variability, overall trends in Δ18O(Qtz-Ep) from rims on adjacent grains (and thus temperature, assuming rims equilibrated) vs. vertical position are resolved. Δ18O(Qtz-Ep) generally increases (= decreasing temperature) over ~30–100 m vertical transects from the footwall into the d (open full item for complete abstract)

Committee: Craig Grimes Ph.D. (Advisor); Greg Nadon Ph.D. (Committee Member); Damian Nance Ph.D. (Committee Member) Subjects: Geology

Master of Science (M.S.), University of Dayton, 2015, Electro-Optics

Although silicon photodetectors are widely used in the manufacture of consumer cameras and light sensors, their fabrication requires a large number of process steps, equipment and resources. In order to study novel device concepts, such as the inclusion of silicon nanowires, quantum-confinement, nanostructured moth-eye structures or on-chip optical filtering, we need control over critical fabrication steps, which is not possible if we rely only on commercially produced devices. In this work, we have designed, fabricated and characterized silicon photodiodes starting from bare silicon wafers to completely packaged chips. We considered two major configurations – front-side illuminated detectors on standard SSP silicon wafers, and back-side illuminated detectors with ultrathin DSP silicon wafers. Ion implantation process was used for creating the p-n junctions, but we also acquired a diffusion furnace and developed our own process for thermal diffusion from a solid source. We also fabricated silicon nanowires on the front side of the diodes using a gold metal-assisted chemical etching (MACE) process to examine their effects on the optical and electrical performances of the devices. The fabricated devices were tested on a probe station, and then they were packaged, wire-bonded and tested for optical responsivities and quantum efficiencies.

Committee: Andrew Sarangan (Committee Chair); Imad Agha (Committee Member); Joseph Haus (Committee Member) Subjects: Electrical Engineering; Engineering; Optics; Physics

PhD, University of Cincinnati, 2014, Engineering and Applied Science: Environmental Engineering

Black carbon (BC) from vehicular emission in transportation is a principal component of particulate matters ≤ 2.5 μm (PM2.5). PM2.5 and other diesel emission pollutants (e.g., NOx) are regulated by the Clean Air Act (CAA) according to the National Ambient Air Quality standards (NAAQS). This doctoral dissertation details a study on transport behaviors of black carbon and PM2.5 from transportation routes, their relations with the atmospheric structure of an urban formation, and their relations with the use of biodiesel fuels. The results have implications to near-road risk assessment and to the development of sustainable transportation solutions in urban centers. The first part of study quantified near-roadside black carbon transport as a function of particulate matter (PM) size and composition, as well as microclimatic variables (temperature and wind fields) at the interstate highway I-75 in northern Cincinnati, Ohio. Among variables examined, wind speed and direction significantly affect the roadside transport of black carbon and hence its effective emission factor. Observed non-Gaussian dispersion occurred during low wind and for wind directions at acute angles or upwind to the receptors, mostly occurring in the morning hours. Meandering of air pollutant mass under thermal inversion is likely the driving force. In contrary, Gaussian distribution predominated in daytime of strong downwinds. The roles of urban atmospheric structure, wind fields, and the urban heat island (UHI) effects were further examined on pollutant dispersion and transport. Spatiotemporal variations of traffic flow, atmospheric structure, ambient temperature and PM2.5 concentration data from 14 EPA-certified NAAQS monitoring stations, were analyzed in relation to land-use in the Cincinnati metropolitan area. The results show a decade-long UHI effects with higher interior temperature than that in exurban, and a prominent nocturnal thermal inversion frequent in urban boundar (open full item for complete abstract)

Committee: Timothy Keener Ph.D. (Committee Chair); Eileen Birch Ph.D. (Committee Member); Mingming Lu Ph.D. (Committee Member); George Sorial Ph.D. (Committee Member) Subjects: Environmental Engineering

MS, Kent State University, 2013, College of Arts and Sciences / Department of Biological Sciences

Replication protein A (RPA) is known to interact with guanine- (G-) rich sequences that adopt G-Quadruplex (GQ) structures. Most studies reported in the literature were performed on GQ formed by homogeneous sequences, such as the human telomeric repeat, and RPA's ability to unfold GQ structures of differing stability is not known. We compared the thermal stability of three potential GQ-forming DNA sequences (PQSs) to their stability against RPA-mediated unfolding using single-molecule fluorescence resonance energy transfer (FRET) and bulk biophysical and biochemical experiments. One of these sequences is the human telomeric repeat and the other two, located in the promoter region of tyrosine hydroxylase gene, are highly heterogeneous sequences that better represent PQSs in the genome. The three GQ constructs have thermal stabilities that differ significantly. Our measurements showed differential behavior of RPA in unfolding GQ structures from different sequences. The most thermally stable structure (Tm = 86 degrees Celsius) was also the most stable against RPA-mediated unfolding, although the least thermally stable structure (Tm = 69 degrees Celsius) had at least an order-of-magnitude higher stability against RPA-mediated unfolding than the structure with intermediate thermal stability (Tm = 78 degrees Celsius). The significance of this observation becomes more evident when considered within the context of the cellular environment where protein-DNA interactions can be an important determinant of GQ viability. We also systematically studied the stability of G-Quadruplex structures against RPA, changing two factors, viz; the number of G-quartets in the structure and number of nucleotides in the intermediate loop. Considering these results, we conclude that thermal stability is not necessarily an adequate criterion for predicting the physiological viability of GQ structures and that there is a linear relationship between the number of G-quartets and number of nucleotid (open full item for complete abstract)

Committee: Hamza Balci Ph.D. (Advisor); Edgar Kooijman Ph.D. (Committee Member); Gail Fraizer Ph.D. (Committee Member) Subjects: Biochemistry; Biology; Biophysics

Master of Science, The Ohio State University, 2013, Mechanical Engineering

This thesis describes potential configurations and responses of panels for experimental tests investigating fluid-thermal-structural interactions. The United States Department of Defense (DoD) and the National Aeronautics and Space Administration (NASA) are both interested in hypersonic vehicles due to their incredible capabilities for long range strike, surveillance and responsive access to space. These vehicles experience combined extreme aerodynamic heating and pressure loads. In addition, the structural loads are greatly affected by temperature-dependent material properties. Prediction of the response of these structures requires accurate, coupled fluid-thermal-structural analysis over long time records. High fidelity modeling over these long trajectories is prohibitively expensive computationally. In addition, validation of approximate models is limited due to the lack of experimental data capturing coupled fluid-thermal-structural interactions. The aim of this thesis is to explore the potential for experimental studies of fluid-thermal-structural interactions for validation and basic discovery purposes. Panel flutter is examined in this study, due to a simpler configuration for modeling. In order to accomplish the goal of this work, potential experimental facilities are explored to determine the conditions under which panels could be tested. An examination of common nondimensional parameters related to panel flutter is conducted to determine the utility of these parameters. A study of different panel configurations is conducted to determine the effect on panel response of varying flow conditions, boundary conditions and panel materials. Finally, the potential panel configurations that could be tested in two different facilities are discussed. It is found that there is a range of potential panel configurations that could be examined experimentally. For smaller facilities, the difference between the thinnest and thickest panels which exhibi (open full item for complete abstract)

Committee: Jack McNamara PhD (Advisor); James Gregory PhD (Committee Member) Subjects: Aerospace Engineering; Mechanical Engineering