Doctor of Philosophy (PhD), Wright State University, 2019, Engineering PhD

Drop on demand (DOD) inkjet printing has been widely investigated for its low cost, noncontact, high throughput, and reproducible process advantages. This dissertation research sought to capitalize on these advantages for use in micro solid oxide fuel cells (micro SOFCs). Understanding the important variables underpinning the inkjet process, including ink formulation, jet kinematics, and process settings was essential. These variables were evaluated for their impact on drop deposition quality, resolution, microstructure, and electrochemical functionality, with the end goal of making submicron to micron scale ceramic features. Initially, the fluid kinematics of single pass printing was investigated using a dilute, solid-solvent, colloidal, ink suspension of of La0.6Sr0.4Fe0.8Co0.2O3 (LSFC) and α-terpineol. Favorable process conditions were identified that attained uniform, well-shaped, circular dots ~ 0.1 μm thick and ~ 80 μm in diameter. Multiple, sequential ink passes were employed to increase feature dimensions on the x/y/z axes. This required additional process constraints to control deposition quality and resolution of micro features including micro-dots (0-D), micro-lines (1-D) and micro-planes (2-D). Using optimal conditions, 0-D dots and 1-D lines with x/y dimensions < 100 μm and z axis dimensions < 1 μm with dense, open or networked microstructures were demonstrated; in addition 2-D planes having smooth surface and continuous intra-planar ceramic coverage with dimensions as small as ~ 100 μm by ~ 100 μm were achieved. Sintering the inkjetted submicron prototypes produced consolidated submicron films that were uniform, smooth and void of defects such as cracks or delamination. Thermal treatments resulted in grain growth from an average crystallite size of ~158 nm to ~ 356 nm. Heat treatments < 800°C were essential to avoid deleterious effects on electrochemical activity. Electrochemical characterizations of prototypes produced tolerable peak power (open full item for complete abstract)

Committee: Hong Huang Ph.D. (Advisor); Sharmila Mukhopadhyay Ph.D. (Committee Member); Jason Deibel Ph.D. (Committee Member); Lei Kerr Ph.D. (Committee Member); Thomas Reitz Ph.D. (Committee Member) Subjects: Engineering; Materials Science

Master of Science (MS), Ohio University, 2017, Environmental Studies (Voinovich)

Madagascar is home to a broad array of intriguing, endemic, and increasingly endangered species. The fosa (Cryptoprocta ferox) is the largest living (non-introduced) mammalian carnivore on the island and is considered a keystone species for maintaining ecosystem complexity in a broad range of Madagascar's forested habitats. Sadly, the fosa is threatened, with viable populations remaining in only two protected areas. In this context, complex interactions among fosa, prey, and myriad introduced species, reveal a dynamic that is increasingly sensitive to human pressures (e.g., hunting, deforestation for agriculture and fuel wood). This project assembles detailed geographic information to augment long-term data collection and help inform the fosa conservation effort. Research was conducted in Ankarafantsika National Park, a dry deciduous forest in the northwest region of the country, and one of the two places where viable fosa populations still exist. Species encounters and trap rates, roadkill patterns, and the spatial and activity patterns of GPS-collared fosas were analyzed to gather a comprehensive assessment on habitat pressures experienced by the fosa. Species encounter and trap rates documented a shift in prey item encounters over time. Roadkill surveys, together with the roadkill death of one of the GPS-collared study animals, demonstrated failure of current mitigation efforts in addressing roadkill dangers. Fosa space use and activity patterns clearly reveal that they rely almost exclusively upon forested habitats, and that they avoid human settlements. Interestingly, although fosa do rely heavily on forest habitat, their ability to use forest edges and narrow forested strips suggests that corridors may be a viable method to enhance habitat connectivity and promote positive conservation outcomes.

Committee: Nancy Stevens (Advisor); Geoffrey Dabelko (Committee Member); Viorel Popescu (Committee Member) Subjects: Environmental Studies; Wildlife Conservation

Master of Science, The Ohio State University, 2014, Chemistry

RNA interference is a powerful tool in gene therapy. The major limitations in utilizing small interfering RNA (siRNA)-based strategies are poor delivery of siRNA across cell membranes and low bioavailability of siRNA in the cytosol. Therefore, several delivery systems have been developed in order to improve cellular uptake of siRNA. Fusion peptides are a delivering agent that has been shown to successfully deliver siRNA through the cellular membrane to the cytoplasm, inducing a gene-silencing response. The 23 residues at the N-terminus of glycoprotein gp41 of HIV-1 is known as a fusion sequence that catalyzes the fusion of the viral membrane and host’s cell membrane, propagating viral infection. Several investigators studied the role of this fusion peptide in fusion reactions in order to understand the fusion mechanism and extract the required elements for fusogenicity. Our study is the first attempt to optimize fusogenic function of the HIV fusion peptide through sequence variation. In our previous study, a library of 38 modular hydrophobic-cationic peptide variants were synthesized with mutations of the 23-residue fusion peptide domain found at the N-terminus of gp-41 glycoprotein of HIV-1 and their membrane activity was evaluated with respect to fusion (lipid mixing) and lysis (content leakage, permeability). We found that peptide variants behaved in accordance with the bridging model in which flexibility, appropriate hydrophobic sequence and electrostatic anchor are requirements to cause the fusion of two opposed membrane vesicles. Glycine does not seem to be important for fusogenicity. Moreover, we found that the sequence of the fusion peptides could be modified to express higher fusogenicity and lower permeability, relative to the native sequence. Based on this previous report, we studied the potential of fusion peptide variants in RNAi therapeutics. Thereby, fusion peptide variants were assayed for their ability to deliver FAM-GL3 siRNA into A549 cell (open full item for complete abstract)

Committee: Dennis Bong Professor (Advisor); Thomas Magliery Professor (Committee Member) Subjects: Chemistry

PhD, University of Cincinnati, 2005, Arts and Sciences : Geography

An agent-based crime event and crime pattern simulation model is developed in this research. The purpose of the simulation model is to provide a computational laboratory for environmental criminologists to study the interactions among offenders, targets, controllers, and crime places. The simulation model also aims to provide a useful tool for teaching crime event theories. Routine activity theory and crime pattern theory are the theoretical foundations of the simulation model. Agent-based modeling coupled with cellular automata addresses the complex crime event process of street robbery. A type of spatial autonomous agent is developed with a wayfinding capability on the urban street network. The wayfinding algorithm is based on a reinforcement learning algorithm. Offender agents, target agents and police agents are developed based on the spatial autonomous agent, which can be released on a street network to execute their routine activity schedules. The interactions among offender agents, target agents, police agents, and crime places create crime events and crime patterns for analysis. Offender agents and target agents can learn from their past offending/victimization experience and change their spatial behaviors. The crime event and crime pattern simulation model is tested to be able to generate credible spatial, temporal, victimization, and offending patterns. The simulation model is then applied to examine the effect of agent adaptations on spatial crime patterns, offending patterns and victimization patterns. The power-function distributions of crime events among crime places and offender population are examined as emphases. Targeted for MS Windows desktop, the RA/CA/ABM computational laboratory is implemented using Visual C++. The computational laboratory has a graphic user interface that allows users to customize the simulation model, control the simulation process, visualize agent movement and crime patterns during the simulation, and query agent properties (open full item for complete abstract)

Committee: Dr. Lin Liu (Advisor) Subjects: Geography

Doctor of Philosophy, The Ohio State University, 2009, Geography

Human space-time activities are dynamic with many interacting dimensions. The analysis of human space-time activity patterns plays important roles for the understanding of many phenomena, such as urban sprawl and growth, transport planning and management, locating new facilities, disease outbreak control, etc. Understanding the dynamics of human space-time activities in human and environment systems, reasoning their relationships, modeling spatio-temporal behavior, and predicting future changes are essential for many people-based applications. In transportation research community, the analysis of space-time activity patterns has been extensively studied, but some issues have not been sufficiently addressed so far. First, space and time are two fundamental dimensions that are important for the understanding of spatiotemporal activity patterns. However, they are often analyzed separately, which makes the interpretation of space-time interaction difficult. Second, human activities take place in the real world, but few of the existing research can handle activity pattern with real geographic locations that are important to reason the space-time relations. Recently, GIS-based time-geographic analysis has been proposed to analyze human space-time activity patterns and it proves to be an efficient to understand complex patterns with real geographic locations. However, the number of individuals can be analyzed by this method is still limited, which limits broader applications. In this research, group pattern analysis based on GIS-based time-geographic analysis has been proposed based on activity pattern classification and geovisualization. This research aims to solve the following key problems in the classification of human space-time activity patterns. First, what kind of mathematic measures can be developed to compare the differences between space-time activity patterns with many interacting dimensions? Second, based on the time-geographic approach, how to analyze and cla (open full item for complete abstract)

Committee: Mei-Po Kwan (Committee Chair); Morton O'Kelly (Committee Member); Ningchuan Xiao (Committee Member) Subjects: Geography

MA, Kent State University, 2007, College of Arts and Sciences / Department of Anthropology

Mammal brains may evolve through selection on specific neural structures. Thus, they may be under varying evolutionary pressures. This study investigates the effect of environmental influences, such as diet, home range size, activity pattern and habitat, on primate hippocampal volume size, which appears to be responsible, in part, for spatial memory skills. In both species and phylogenetic independent contrast analyses, a highly frugivorous diet had no impact on hippocampus volume size. Due to exceptions to the rule that primates with mainly insectivorous diets tend to be smaller-bodied, log body mass was plotted against percentage of frugivorous diet. When frugivorous-insectivore outliers were removed, the size-adjusted hippocampus volume residual from medulla oblongata volume was found to increase in primates with a highly frugivorous diet. Conversely, primarily insectivorous primates demonstrated a negative correlation with hippocampal size, suggesting they have smaller hippocampi than folivorous or frugivorous primates. In addition, hippocampus volume was shown to increase as home range size increased. Diurnal and nocturnal activity patterns as well as arboreal, semi-terrestrial and terrestrial habitats had no effect on primate hippocampus volume size. These results suggest that environmental pressures involved with diet and home range size may selectively pressure for an increase or decrease in primate hippocampus size due to its role in spatial memory. This is the first study to demonstrate a selective environmental pressure on primate hippocampus volume size.

Committee: Chet Sherwood (Advisor) Subjects: Anthropology, Physical