Doctor of Philosophy, Case Western Reserve University, 2021, Nursing

Heat stress is a serious problems affecting surgeons in operating rooms where insulated surgical gowns and personal protective equipment (PPE) must be worn. Heat stress is an increase in core body temperature and/or in mean skin temperature, which results from the total environmental, situational, and personal demands imposed on the surgeon and the surgeon's inability to eliminate metabolic heat produced while wearing PPE. Little is known about the surgeons' development of heat stress in real-time operating room conditions and the degree of increased body temperature and thermal discomfort sufficient to impair cognitive performance. The aims of study are to 1) describe the environmental, personal, and situational variables before and after surgery on two separate days, 2) describe the differences between the variables from pre- to post- operation each day of the study, and 3) determine the associations between the environmental, personal, and situational variables each day of the study. A one group pre-and-post correlational study of 30 orthopedic surgeons performing total-joint procedures expected to last between 90 to 150 minutes on two separate days during real-time surgical operations was conducted. The surgeons wore sensors to obtain core and skin temperatures, completed a cognitive battery test, rated thermal comfort pre- and post- operation as well as post- operation perceptions of sweat11 soaked clothing, exertion, and fatigue each day of study. Statistical analysis described the values, differences, and associations of the data collected pre- and post- operation. The surgeons' core and mean skin temperatures increased ≥ 1⁰ C on both days of study. Cognitive test scores revealed an increase in processing speed scores and a decrease in visual memory scores. The surgeons' perceptions of thermal comfort were significantly warmer after completing surgery. Overall, the associations of the variables in the study did indicate a number of mea (open full item for complete abstract)

Committee: Susan M. Ludington-Hoe Ph.D., RN, CNM, FAAN (Committee Chair); Nora L. Nock Ph.D., CE (Committee Member); Christopher Burant Ph.D., MACTM (Committee Member); Joachim Voss Ph.D., RN, ACRN (Committee Member) Subjects: Environmental Health; Health Care; Nursing; Occupational Health; Occupational Safety; Physiology; Psychology

MS, University of Cincinnati, 2011, Medicine: Occupational Medicine

Limited studies have documented the cardiovascular strain of firefighting. Cardiovascular disease causes nearly 50% of on-duty deaths among U.S. firefighters each year. The study examined the effects of live-and non-live fire drills on cardiovascular and psychophysical responses of 12 male firefighters and 1 female firefighter. In this experimental pre- and post-scenario study design, participants performed three standardized tasks while inside a steel building during their regularly scheduled training drill. Fire training sessions involved a set of three tasks including: hose advancement, search and rescue, and backup, each performed for three to four scenarios. Scenarios included first floor fire, second floor fire for which firefighters had to climb a flight of stairs and basement fire for which firefighters had to descend a flight of stairs. Data on vital signs were collected before training and then pre- and post-scenario. Heat stress is an important contributory risk factor for cardiovascular disease in firefighters. During the training, continuous core body temperature (CT) and heart rate (HR) data were collected using a FDA-regulated radio pill and a Polar heart rate belt, respectively. The radio pill and heart rate belt transmitted data to a receiver that was placed in the inside pocket of the firefighter's turnout coat. Psychophysical data were collected pre- and post-scenarios, which included perceptions of thermal distress, physical exertion, and respiratory distress. Our hypothesis was that there would be a significant increase from pre-scenario to post-scenario values of cardiovascular and psychophysical parameters. Results showed that there was a significant increase in average heart rate (23%) with a p<0.05 for pre-to post-scenario 2 and a p<0.05 for pre- to post-scenario 3. Percent maximum oxygen consumption resulted in maximal heart rates and reductions from pre- to post-scenarios. Pre-scenario mean was: lower limit=58% and upper limit=69% (n=6). P (open full item for complete abstract)

Committee: Amit Bhattacharya PhD (Committee Chair); Clara Ross MD (Committee Member); Paul Succop PhD (Committee Member) Subjects: Occupational Safety

Doctor of Philosophy, The Ohio State University, 2019, Horticulture and Crop Science

Creeping bentgrass (Agrostis stolonifera L.) is a turfgrass species that is widely used on golf courses throughout the United States. It can withstand extremely low mowing heights and can provide a dense cover making it an ideal species for low cut areas of the golf course. However, at times it is subjected to environmental stresses such as heat and salt. In field settings plants are often subjected to more than one stress at a time and studying stresses independently is likely insufficient. These stresses can affect plant hormone levels and, in turn, plant hormone levels can affect how well the plant tolerates stress. There were two experiments conducted. In the first experiment creeping bentgrass was transplanted into hydroponics systems in two different growth chambers. One chamber was set to have day and night time temperatures of 35 and 30-degrees Celsius, respectively. The other was set to have a day and night time temperatures of 25 and 20-degrees, respectively. Within each chamber one block received a 50 mM sodium chloride (NaCl) treatment and the other did not. The stress treatments were applied for 14 days. The experiment was repeated four times. Results of the first experiment indicated that the treatments were sufficient to negatively affect creeping bentgrass growth and health as indicated by fresh shoot and root weights, tillering, electrolyte leakage and total chlorophyll content (TCC). There were significant interactions between temperature and salt level detected for shoot and root weights and electrolyte leakage. Plants that were exposed to both heat and salt stress were more negatively affected than plants exposed to either heat or salt stress alone for all metrics except for tillering. The presence of NaCl reduced tillering regardless of temperature regime. In the second experiment plants were treated the same, but plant growth regulator (PGR) treatments were also applied. The second experiment was repeated six times and PGR tre (open full item for complete abstract)

Committee: David Gardner PhD (Advisor); Joshua Blakeslee PhD (Committee Member); Karl Danneberger PhD (Committee Member); Edward McCoy PhD (Committee Member); James Metzger PhD (Committee Member) Subjects: Agriculture; Agronomy

Doctor of Philosophy, The Ohio State University, 2009, Plant Cellular and Molecular Biology

The nuclear pore complex (NPC) is essential for macromolecular trafficking and facilitates the exchange of information between the nucleus and the cytoplasm in the eukaryotic cells. The fungal and mammalian NPCs have been well studied through a variety of methods, including isolation of NPCs and identification of the component proteins. In plants, both the protein components of and various molecular activities associated with the NPC are poorly understood. Recent studies have implicated the plant NPC in several cellular processes, including plant-microbe interactions, hormone signaling, mRNA export and stress tolerance. This highlights the necessity to thoroughly understand NPC-associated molecular activities in plants. In other systems, proteins found in the NPC also have functions during mitosis, specifically in spindle assembly. Spindle assembly checkpoint (SAC) proteins are crucial for proper cell division across the eukaryotes. I have characterized Arabidopsis nucleoporin, NUA, and have identified and characterized an Arabidopsis SAC protein, AtMAD1. My work suggests that NUA has functions during mitosis and that it interacts with AtMAD1.

Committee: Iris Meier (Advisor); Rebecca Lamb (Committee Member); Jyan-Chyun Jang (Committee Member); Venkat Gopalan (Committee Member) Subjects: Cellular Biology

PhD, University of Cincinnati, 2023, Nursing: Nursing - Doctoral Program

Heat-related illness (HRI) is entirely preventable yet persists despite continued efforts. Incidents of HRI are increasing in frequency and are projected to exacerbate due to the effects of climate change. Farmworkers have some of the highest deaths and incidents related to HRI, yet the factors related to farmworkers' use of prevention measures are not understood. Moreover, to our knowledge, there is no research on Ohio farmworkers and HRI or HRI prevention. This manuscript format dissertation aimed to understand the factors related to HRI prevention in farmworkers. Three projects were undertaken to ascertain these factors: (1) a scoping review of the recommendations for prevention of HRI, (2) an integrative review of the barriers to the use of prevention measures, and (3) an ethnographic study of Ohio farmworkers and HRI. Project 1 followed PRISMA-ScR guidelines for scoping review of literature. Project 2 followed Whittemore and Knafl's integrative review guidelines. Project 3 followed an ethnographic study design collecting data from observations and semi-structured interviews with farmworkers and other potentially affected community members. Project 1 used the Haddon Matrix to compile and summarize the recommendations for the prevention of occupational HRI for outdoor workers but found that the recommendations were lacking in secondary and tertiary recommendations. Project 2 uncovered four themes to barriers to prevention of HRI for farmworkers: (1) access, (2) education and training, (3) culture, and (4) compensation. In Project 3, four themes were found related to Ohio farmworkers and HRI including: (1) Acquisition and Interpretation, (2) Perception, (3) Interoception, and (4) Action. Conclusion: Gaining a better understanding of the factors affecting farmworkers use of HRI prevention measures is a good start in improving their safety. Clear and detailed guidelines must first be in place for farm owner (open full item for complete abstract)

Committee: Gordon Gillespie Ph.D. (Committee Chair); Beverly Hittle Ph.D. (Committee Member); Amit Bhattacharya Ph.D. (Committee Member) Subjects: Nursing

MS, Kent State University, 2023, College of Architecture and Environmental Design

In the summer of 2021, the Northwest faced an unprecedented heatwave, leading to over 250 fatalities in the United States, more than 400 in Canada, and a surge in heat-related emergency cases. This study focuses on mitigating heat stress in Portland, USA, by investigating how urban layouts influence heatwave impacts at a microclimatic scale. To assess heat stress during heatwaves, the Universal Thermal Climate Index (UTCI) was employed, which comprehensively assesses the combined effects of several factors on human comfort. Five distinct urban areas were selected based on the addresses of individuals who tragically lost their lives during the heatwave in June and July 2021. Over ten days (equivalent to 240 hours), from June 23 to July 2, 2021, simulations were conducted using the ENVI-Met. The findings indicate that all five urban areas demonstrated consistent responses during moderate, strong, very strong, and extreme heat stress episodes, with only slight variations between them. Specifically, when UTCI reached its peak, all locations within the studied areas experienced high UTCI levels. This indicates that even in areas with partial tree coverage or tall buildings providing shade, there is no absolute refuge from severe heat stress during "extreme heat stress" (UTCI≥46°C) or even "very strong heat stress" (38°C ≤ UTCI < 46°C) conditions. However, distinctions in the daily maximum UTCI values were noted among the areas, especially at lower temperatures. Areas near the Columbia River or abundant tree cover usually recorded lower daily maximum UTCI values, while areas characterized by compact high and medium-rise buildings with a few trees consistently displayed the highest daily maximum UTCI values during heatwaves. Furthermore, sites with abundant tree cover or proximity to the sea experienced fewer hours of heat stress (UTCI≥26°C) across various intensity levels and reduced instances of "extreme heat stress" (UTCI≥46°C). Conversely, compact urban areas with ta (open full item for complete abstract)

Committee: Adil Sharag-Eldin (Advisor); Christopher Woolverton (Committee Member); Pravin Bhiwapurkar (Committee Member) Subjects: Architecture; Climate Change; Environmental Health; Environmental Studies; Health; Urban Planning

Honors Theses, Ohio Dominican University, 2022, Honors Theses

The purpose of this research experiment was to analyze if different temperature conditions engender different phenotypic responses in Early Scarlet Globe radishes. This experiment looked at two groups of Early Scarlet Globe radishes, with Group A, grown indoors at 70°F, and group B, grown indoors under a heating lamp, compatible with a 60W light bulb, in the same 70°F environment during two phases. In both Group A and Group B, 120 Early Scarlet Globe radish seeds were planted. In the first phase, the number of radish seedling sprouts, the average number of leaves per sprout, the average stem elongation, and the height of the tallest stem of the Early Scarlet Globe radishes were recorded. In the second phase, the yield of mature radishes, the average number of leaves, the average stem elongation, the height of the tallest stem, the dimensions of the leaf blade, and the diameter and color of the mature radish bulb were recorded. In phase one, the results showed that there was a statistical significance in the means for the number of leaves and the height of the tallest stem, given that the p-values were 0.046 and 0.042, respectively. In phase two, the results indicated a positive correlation between the average stem elongation and the average length of the leaf blade (slope = 0.589, R² = 0.458) and a positive correlation between the average stem elongation and the average width of the leaf blade (slope = 0.319, R² = 0.379). The Early Scarlet Globe radishes in Group B of phase two showed smaller averages for the leaf blade length and width, highlighting the detrimental effects of heat stress on radish leaves, which are important for carrying out the process of photosynthesis due to the presence of chloroplasts.

Committee: Blake Mathys (Advisor); John Marazita (Other); Annie Witzky (Other) Subjects: Ecology

Master of Science, University of Toledo, 2022, Biology (Ecology)

Atmospheric carbon dioxide (CO2) concentrations are increasing and may exceed 800 ppm by 2100. This is increasing global mean temperatures and the frequency and severity of heatwaves. Recently, it was shown for the first time that the combination of chronic warming and elevated carbon dioxide (eCO2) caused extreme upward bending during growth (i.e., hyponasty) of leaflets and leaf stems (petioles) in tomato (Solanum lycopersicum), which reduced growth. However, that study examined only two levels of CO2 (400, 700 ppm) and temperature (30, 37oC) at the young vegetative plant stage. Further, they did not investigate underlying mechanisms for this warming + eCO2-induced hyponasty, which is likely to involve the plant hormones auxin and ethylene, based on their role in thermal hyponasty. In this study, warming + eCO2 hyponasty was evaluated in tomato across a range of temperatures and CO2 concentrations, and at multiple life stages. Ethylene tomato mutants were examined to explore the potential role of these hormones in warming + eCO2 hyponasty. Lastly, other species were examined to test the hypothesis that warming + eCO2 hyponasty is restricted to compound-leaved species in this family. At eCO2 (800 ppm), petiole angle increased ca. linearly as temperature increased from 30-38oC. Under heat stress (HS, 38°C), petiole angle increased at all eCO2 concentrations compared to ambient (600/800/1000 vs. 400 ppm). All life stages examined (juvenile, pre-reproductive, and flowering) had increased petiole angle in leaves developed during warming + eCO2, such that most leaves exhibited hyponasty in juvenile plants but only young leaves did so in adults (previously fully-developed leaves were unaffected). Ethylene-insensitive (nr) and -constitutive (epi) mutants displayed similar changes in petiole angle with warming + eCO2 compared to the non-mutant reference (cv. Celebrity), indicating that ethylene is not a main component of the mechanism of this hyponastic response. (open full item for complete abstract)

Committee: Scott Heckathorn Dr. (Committee Chair); Heidi Appel Dr. (Committee Member); Jennifer Boldt Dr. (Committee Member) Subjects: Agriculture; Agronomy; Biology; Botany; Climate Change; Ecology; Environmental Science; Forestry; Morphology; Physiology; Plant Biology; Plant Sciences

Doctor of Philosophy, The Ohio State University, 2021, Welding Engineering

Stress Relief Cracking (SRC) in low alloy steels was the core focus for this work. Stress relief cracking is an ongoing concern for thick-walled creep resistant steel welds during PWHT when high restraint and high residual stresses are present after welding. While much is already known about SRC, the persistence of its occurrences motivates continued research to further study this cracking phenomenon due to the desire to completely eliminate SRC occurrences during future fabrications. This body of research can be broken into three elements, SRC test development, analysis of the SRC mechanism and controlling factors, and modeling. The goal was to develop a test that can accurately recreate the SRC mechanism which would then be used to study SRC as it naturally occurs in weldments during PWHT. Grade 11 and Grade 22 Steel were the primary focus of this research. A Gleeble based SRC testing procedure was developed at The Ohio State University in order to carry out experimentation for this research. SRC occurs in highly restrained welds where high residual stresses are present after welding. Past research has shown stress can affect the precipitation kinetics in low alloy steels making the recreation of high residual stress crucial for replicating the microstructural evolution of susceptible materials during both heating and PWHT. The OSU SRC Test procedure loaded a dog bone to 90%YS at room temperature, then while heating to PWHT temperature at 200°C/hour, additional Gleeble stroke was added to counteract the compressive strain from thermal expansion with the goal of the sample reaching 90% of its elevated temperature YS upon reaching PWHT temperature. The Gleeble displacement was fixed upon reaching PWHT temperature to simulate high restraint and the sample was held for 8 hours. Digital image correlation was utilized for measuring strain across the surface. All results of testing showed the OSU SRC Test is accurately determining SRC susceptibility as well as accu (open full item for complete abstract)

Committee: Boian Alexandrov (Advisor); Avi Benatar (Advisor); Wei Zhang (Committee Member); Carolin Fink (Committee Member); Desmond Bourgeois (Committee Member) Subjects: Engineering; Materials Science; Metallurgy

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

Regulation of brain temperature is critical for managing heat stress-related adverse events. It can be achieved by external cooling of the head. Head cooling systems that are lightweight, portable, and suitable for active work scenarios, such as firefighting, mining, and construction work, are currently unavailable on the market. This study proposes a novel active head cooling system that a) uses phase change material for thermal storage and b) can be designed for portability. The closed-loop bench-top system consists of two heat exchangers: a water-cooled heat exchanger with an attached heater, mimicking heat generated from the head, and a helical tube heat exchanger surrounded with ice as a heat sink. These heat exchanges are interconnected by tubing for water circulation. The system performance is assessed by the cooling duration that depends on the mass of ice used and the heat transfer rate. The system was evaluated for different heat loads varying from rest to exercise condition (20 W – 40 W) and flowrates (0.25 l/min – 0.65 l/min). The results show that the system can handle a heat generation rate of 40 W from the head for 100 min (for the flowrate of 0.25 l/min), which is about 3 times the safe duration of firefighting drills. The cooling time increases linearly with decreasing heat load: 138 min for 30 W and 190 min for 20 W, an increase of 38%, and 90%, respectively. It also increases with a decreasing flow rate. The range of Nusselt number for helical coil flow is about 4.4 – 6.8 times higher when compared to that of a straight pipe flow. The helical design of the heat exchanger leads to enhanced heat transfer owing to the formation of Dean's vortical flow. The results suggest that the head cooling system, having possible features of being portable, cost-effective, lightweight, and easy to use, can assist in the thermoregulation of brain temperature for workers during elevated thermal stress conditions.

Committee: Rupak Banerjee Ph.D (Committee Chair); Marwan Al-Rjoub Ph.D. (Committee Member); Je-Hyeong Bahk Ph.D. (Committee Member); Amit Bhattacharya Ph.D. (Committee Member); Michael Kazmierczak Ph.D. (Committee Member) Subjects: Mechanical Engineering

Master of Science (MS), Ohio University, 2020, Molecular and Cellular Biology (Arts and Sciences)

Coordination between chloroplasts and the rest of the cell is indispensable for stress responses in plants. The high reduction status of chloroplasts requires a sophisticate balance of metabolic homeostasis, which leads chloroplasts extremely sensitive to environmental perturbations. Null mutants of chloroplast proteins can cause propagating effects on stress response, even resulting in death. For example, mutants for Differentiation and Greening Like (DAL) lead to loss of green pigmentation, damaged RNA editing process in chloroplasts, and lethality at the early seedling stage. However, the exact biochemical function of DAL remains unclear. We hypothesized that DAL is a novel stress responsive protein based on the biochemical, genetic and transcriptomic studies of DAL in the metabolic pathway. To further demonstrate this hypothesis in my thesis, I overexpressed DAL along with its three different truncations that lack 12, 21, and 48 amino acids at the N-terminus. All these recombinant proteins were fused with a yellow fluorescent protein (YFP) at the C-terminus. I discovered that all overexpressing transgenic plants grew at a slower pace at a normal long-day growth condition (16-h light/8-h darkness at 21°C/19°C, respectively) but had a higher tolerance to heat shock. Confocal microscopy analysis found that DAL full length proteins and the truncations lacking the N-terminal 12 amino acids seemed to be patricianly, but not all, localized in chloroplasts while the other two truncated derivatives retained in cytosol. Additionally, overexpressing the full-length version of DAL resulted in the plants more susceptible to salt than its truncations and WT plants when they were directly germinated and grown on 50 and 100 mM NaCl-containing half-strength Murashige-Skoog medium. Taken together, I concluded that DAL has multiple intracellular functions, some of which are differentiated by a 48-amino acid short peptide at its N-terminus.

Committee: Zhihua Hua (Advisor); Sarah Wyatt (Committee Member); Micheal Held (Committee Member) Subjects: Plant Biology

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

In the current thesis, an analysis of energy separation in a Ranque-Hilsch Vortex Tube (RHVT or simply VT) using results from CFD has been performed. Initially the 3D CFD model of the VT was validated against published experimental data and was found to have a very good agreement in terms of total temperature predictions at the hot and cold outlets. The flowfield in the VT was analyzed using RANS based two-equation turbulence model Std k-?. Comparisons were made between a published LES research to get an idea of how the turbulence models differed in their predictions of highly swirling flows like the vortex tube flow which exhibit an anisotropic behavior with respect to turbulence production and the stresses resultantly. The velocities were studied in detail to define the free and forced vortex regions which are found in swirling flows and also to define the cross-over region between the two counter-flowing streams of hot and cold fluid where turbulent stresses and generation of turbulence are expected to be maximum. The turbulence generated at the cross-over region breaks down in the annular region affected by viscosity near walls which causes the turbulence breakdown to heat neat the walls and thus the hot temperature. Next, the other flow properties like the static and total temperatures, vorticity, strain rate and Reynolds stresses inside the VT were studied in detail using the results from the CFD simulation which would have been otherwise very difficult to obtain using experimental techniques. In the further analysis, it was found that there is a flow of energy in the form of work and heat from the core flow to the annular flow region which causes the core flow temperature to drop and that of the annular flow to increase. A control volume (CV) analysis was performed with the cold flow forming the control volume and the CV boundary being defined by the cross-over region between the cold and hot flow. The calculations were in very good agreement with the assu (open full item for complete abstract)

Committee: Peter Disimile Ph.D. (Committee Chair); Shaaban Abdallah Ph.D. (Committee Member); Milind Jog Ph.D. (Committee Member) Subjects: Engineering

Doctor of Philosophy, University of Toledo, 2020, Biology (Ecology)

Atmospheric carbon-dioxide (CO2) enrichment is largely the cause of current global warming. Hence, in the future, organisms will experience the interactive effects of elevated CO2 (eCO2) and chronic warming rather than their individual effects. Though individual effects of eCO2 or chronic warming on plant responses have been studied in some detail, interactive effects of eCO2 and chronic warming on plant responses such as nitrogen (N) relations (uptake, translocation, assimilation) and leaf hyponasty (upward bending of leaves) have been rarely studied. Therefore, the goals of my dissertation work included (1) investigation of eCO2 plus chronic warming on plant N relations, using tomato (Solanum lycopersicum L. cv. Big Boy) and wheat (Triticum aestivum L. cv. Glenn) followed by a meta-analytic review, and (2) investigation of eCO2 plus chronic warming on leaf hyponasty and subsequent effects of hyponasty on plant growth, using tomato and other economically-important species. These goals were achieved by growing plants in a full-factorial experimental design, using two levels of CO2 (ambient vs. elevated) and two temperature regimes (near-optimal vs. supra-optimal) in controlled-environment growth chambers. In all experimental trials conducted, eCO2 plus warming inhibited tomato vegetative growth, whereas warming alone inhibited growth to a smaller extent, and eCO2 alone increased growth. One potential reason for inhibition of plant growth at eCO2 plus warming could be the observed increase in leaf hyponasty. Warming or eCO2 alone caused modest leaf hyponasty, whereas eCO2 plus warming caused severe leaf hyponasty, which correlated with decreased leaf area and biomass. This could be explained by decreased light interception, and thus in situ photosynthesis, as leaves became more vertically-oriented. Severe hyponasty driven by eCO2 plus warming was observed only in the compound-leaved species tested, but not in the simple-leaved species tested. Tomato plants grown at e (open full item for complete abstract)

Committee: Scott Heckathorn (Committee Chair); Heidi Appel (Committee Member); Jennifer Boldt (Committee Member); Michael Weintraub (Committee Member); John Gray (Committee Member); Maria Bidart (Committee Member) Subjects: Agriculture; Biochemistry; Biology; Botany; Climate Change; Ecology; Environmental Science; Physiology; Plant Biology; Plant Sciences

Doctor of Philosophy, The Ohio State University, 2019, Food, Agricultural and Biological Engineering

The U.S. egg industry is the world's second-largest egg producer with an annual production of 5.6 billion kilograms of eggs and provides 81,515 jobs and $22.77 billion to the economy. Due to the very large-scale and concentrated operations, the egg industry is facing crucial challenges in reducing its significant environmental impacts and solving indoor air quality problems. Egg production is a significant contributor of air emissions to the atmosphere, especially ammonia (NH3) emission, which has caused serious concerns on health and the environment, such as soil and water acidification, visibility impairment, and respiratory diseases. Effective management and mitigation of NH3 emissions from layer operations are urgently needed but are limited because of the lack of effective tools for estimating NH3 emissions. It is also in the egg industry's and the public's interests to understand the health and environmental impacts of NH3 on the neighboring communities. The U.S.EPA regulatory air dispersion model AERMOD needs to be evaluated for its performance in estimating NH3 dispersion after being emission from layer houses. In addition, heat stress is a serious problem in layer houses with annual losses of $61-98 million nationwide due to impaired egg production. Global warming further worsens the heat stress problem due to increasing events of hot weather and heavier precipitation. Exposure to high-concentration NH3 is another risk to layers and workers. It damages layers' immune system and egg production and affects workers' health. The problems of heat stress and NH3 exposure are aggravated in layer houses due to non-uniform airflow resulted from current ventilation systems. The knowledge of the spatial and temporal distribution of heat stress and NH3 concentrations inside layer houses is essential for assessing the associated risks of layers and workers and developing mitigation strategies, but is not yet available. This dissertation aims to fill the gap by de (open full item for complete abstract)

Committee: Lingying Zhao (Advisor); Albert Heber (Committee Member); Jiqin Ni (Committee Member); Heather Allen (Committee Member); Ann Christy (Committee Member); Gil Bohrer (Committee Member) Subjects: Agricultural Engineering; Environmental Engineering

Master of Science, University of Toledo, 2018, Biology (Ecology)

Climate change is increasing global average temperatures, and desert ecosystems are predicted to be particularly vulnerable to the effects of climate change. Desert ectotherms such as reptiles are especially threatened by climate change; however, there is a lack of research on both long-term and acute responses to heat-stress that encompasses multiple levels of physiological performance (i.e. whole-organism and cellular). Here, I measured sprint speed, endurance, water content, and heat-shock protein (HSP70) expression in adult and juvenile Greater short-horned lizards (Phrynosoma hernandesi) from a low- and a high-elevation site. I found that acute heat-stress decreased sprint speed in both adults and juveniles, especially in lizards from the high-elevation site; however, acute heat-stress did not affect endurance, HSP70 expression, or water content. Long-term heat-stress decreased water content but did not affect any other physiological measurements. P. hernandesi adults may have not had detrimental physiological responses to either acute or long-term heat-stress because adults may be able to buffer against extreme temperatures through behavioral thermoregulation; however, juveniles may be more resistant to extreme temperatures because they are likely thermoconformers. More research on multiple levels of physiological performance across different life-stages is needed to broaden our understanding of ectotherms' capacity to respond to climate change.

Committee: Jeanine Refsnider-Streby (Committee Chair); Scott Heckathorn (Committee Member); Streby Henry (Committee Member) Subjects: Animals; Biology; Climate Change; Ecology; Zoology

Doctor of Philosophy, The Ohio State University, 2018, Welding Engineering

Subsea high pressure equipment used in production of oil and gas is routinely clad with nickel base alloys for corrosion protection. In the equipment with partial clad for sealing purpose, dissimilar metal interfaces are possibly exposed to the production fluids containing H2S. After cladding, a high hardness heat affected zone (HAZ) is produced in the base metal adjacent to the fusion boundary and is possibly susceptible to hydrogen assisted cracking (HAC) and sulfide stress cracking (SSC). National Association of Corrosion Engineers (NACE) standard MR0175/International Standard Organization (ISO) 15156 requires that HAZ hardness should be less than 22 HRC or 250 VHN. Postweld heat treatment (PWHT) is applied to reduce the HAZ hardness to meet this requirement. However, PWHT causes the carbon to diffuse from the base metal to the weld metal and pile up in a narrow region adjacent to the fusion boundary, possibly causing interface embrittlement. Also, prolonged PWHT can overtemper the base metal and impair its strength. Therefore, the optimal PWHT conditions need to be determined, which reduce the HAZ hardness to meet the industry standard, do not harm base metal strength, and do not increase the HAC and SSC susceptibility near or at the fusion boundary. In this work, nickel base Alloy 625 overlays on F22 (2.25Cr-1Mo) steel and AISI 8630 steel, or F22/625 and 8630/625 dissimilar metal welds (DMWs), were studied. A wide range of PWHT conditions indicated by Hollomon-Jaffe Parameter (HJP) was investigated to determine an optimal balance between HAZ softening and interface embrittlement. Vickers hardness testing revealed that the CGHAZ hardness decreases with the HJP increase due to martensite decomposition. There is a secondary hardening effect in F22 CGHAZ. The hardness of the planar growth zone (PGZ) of the interface and the weld metal increases with HJP, and the PGZ hardness increases at a higher rate than the weld metal. Nanoindentation and optical microsc (open full item for complete abstract)

Committee: John Lippold (Advisor); Boian Alexandrov (Committee Member); David Phillips (Committee Member) Subjects: Engineering; Materials Science; Metallurgy

PhD, University of Cincinnati, 2017, Medicine: Occupational Safety and Ergonomics

Objective: The objective of this laboratory-based study was to investigate the effect of heat/active continuous cooling on the body's physiological responses, postural balance/gait stability, and cognitive function responses of subjects wearing firefighters' encapsulating protective ensembles during exercise in a simulated hot environment. Methods: Twelve healthy physically-fit males were recruited for this cross-sectional study. A maximal graded exercise test was performed before experimental events in order to calculate maximal oxygen uptake and to assess participants' capacity to perform the assigned exercise. Physiological measures (heart rate, body core temperature, mean skin temperature, body weight), perceptual measures (physical exertion, thermal compensation, and respiratory distress), static balance metrics (sway speed, sway area, excursion along x and y axis), dynamic balance associated with gait outcomes (gait velocity, gait cadence, turn duration, turn peak velocity, range of motion and peak swing velocity of torso, arms and legs), cognitive measures (performance rate errors, reaction times) were obtained before and after exercising inside an environmental chamber. Exercise included treadmill walking while wearing encapsulating firefighters' protective ensembles at 40 % maximal oxygen capacity in warm (30°C) and humid (70%) environmental conditions for 40 minutes or until body core temperature ˜ 39 °C. Subjects participated in two randomly assigned sessions of the exercise protocol: control (no cooling) and experimental (active cooling application). For experimental sessions, a cooling garment with tubing sewn into the inside surface of the fabric was worn underneath firefighters' protective ensembles and infused with cooled water (18°C) supplied by an external water circulator. Skin surface areas in contact with the garment for heat exchange included head, torso, forearm, and thigh area. Results: Participants' physiological responses were significan (open full item for complete abstract)

Committee: Amit Bhattacharya Ph.D. (Committee Chair); William Jetter Ph.D. (Committee Member); Darren Kadis (Committee Member); Ming-Lun Lu Ph.D. (Committee Member); Marepalli Rao Ph.D. (Committee Member); W. Williams Ph.D. (Committee Member) Subjects: Environmental Health

PhD, University of Cincinnati, 2017, Education, Criminal Justice, and Human Services: Health Education

STUDY 1 - BACKGROUND: Occupational exposure to heat can result in illness, injury, and death among workers, particularly those in outdoor environments such as emergency oil spill cleanup responders. PURPOSE: This study assessed heat-related knowledge, perceptions, and barriers among oil spill cleanup responders. METHODS: A total of 65 oil spill cleanup responders completed an online survey which examined heat stress during cleanup activities. RESULTS: Of the respondents, most had 25 or more years' experience, worked for companies with 19 or fewer employees, were not classified as safety and health professionals, had a Bachelor's degree or higher, and worked in the northern/central regions of the U.S. While most were knowledgeable about heat stress, the items in which respondents were least knowledgeable were: identifying the difference between heat exhaustion and heat stroke, the appropriate use of salt tablets, the effects of air conditioning on acclimatization, and previous heat-related illness (HRI) as a risk factor. For heat stress knowledge, there was a significant difference between non-safety and health professionals (M = 5.70, SD = 1.081) and safety and health professionals (M = 6.62, SD = 1.024; t = -3.257, p = .002). Respondents reported that they tended to perceive that heat stress can be severe and that HRI's may affect workers. Regarding self-efficacy, most felt confident in contacting emergency medical services, recognizing symptoms, and knowing what to do if a coworker became ill. Discussion: The difference in heat stress knowledge between those with professional safety and health experience and those without experience is confirmatory. Oil spill cleanup responders are at high risk for HRI, injury, and death and those responsible for their training need to be knowledgeable about occupational heat stress. More research is needed to determine further information about knowledge, perceptions, self-efficacy, and barriers at the worker level. STUDY 2 (open full item for complete abstract)

Committee: Keith King Ph.D. (Committee Chair); Ashley Merianos Ph.D. (Committee Member); Rebecca Vidourek Ph.D. (Committee Member) Subjects: Health Education

Master of Science, The Ohio State University, 2016, Nuclear Engineering

Coupling the s-CO2 Brayton cycle to the advanced nuclear reactors generally requires an intermediate heat exchanger (IHX). From an economic viewpoint, it is important to reduce the size and cost of IHX, but at the same time, the thermal hydraulic performances should not be deteriorated. Printed-circuit heat exchanger (PCHE), one of advanced compact heat exchangers, has been demonstrated as a competitive candidate. This thesis mainly focuses on designing a PCHE-type advanced IHX with innovative surface geometry with thermal, economic and mechanical consideration. Among the four outstanding surface geometries, zigzag and S-shaped fin channels are selected for a helium-to-s-CO2 IHX. Since the thermal-hydraulic correlations of the zigzag channel with a variety of geometrical parameters are available, a thermal-economic optimization is carried out to optimize the design of zigzag channel. For such multi-objective optimization problem, the annual total cost and heat exchanger thermal effectiveness are selected as two objectives functions. NSGA-II (a fast and elitist non-dominated sorting genetic algorithm), one of the widely used multi-objective genetic algorithms, is used for searching a group of Pareto-optimal designs. It is found that among the Pareto-optimal solutions, the total cost gradually increases with the thermal effectiveness between 88 and 95% while rises rapidly after the heat exchanger effectiveness exceeds around 95%. The sensitivity study shows that for the solutions with thermal effectiveness below around 95% the heat exchanger core physical length is the dominant factor that causes conflict between the total cost and thermal effectiveness. A similar trend can be observed from both the basic and extended design space. The final selection of the optimal designs obtained from the thermal-economic optimization requires a structural evaluation of surface geometry, especially for high-temperature high-pressure applications. S-shaped fin channels are ch (open full item for complete abstract)

Committee: Xiaodong Sun (Advisor); Tunc Aldemir (Committee Member); Richard Christensen (Committee Member) Subjects: Nuclear Engineering

Doctor of Philosophy, University of Akron, 2016, Mechanical Engineering

Waste heat energy harvesting has been one of the techniques used to reduce emission of CO2 and improve efficiency of power generation, oil mining and different industrial processes. Nearly 90% of waste heat is considered low-grade (< 230OC) and is unsuitable for traditional waste heat recovery techniques. Thus, a non-continuous SMA Energy Harvesting prototype (EHP) to convert low-grade heat into electricity is presented in this research. We first demonstrate the feasibility of EHP using non-continuous shape memory alloy actuators (SMA) to convert waste heat energy to electricity. Both linear and spring shaped SMA wires made of NiTi alloy have been used to evaluate the energy harvesting capability of EHP. The experimental results proved that the EHP can generate oscillatory shaft rotation. The EHP test where the generator was connected to the main shaft through gear-box provided nearly 10V and 2.5rads shaft rotation in 0.3s. It was also found that the helical spring SMA actuator energy conversion factor was higher than that of the linear SMA actuator. Next, energy storage on both super-capacitors and micro-capacitors by the EHP with the helical spring SMA wire was explored. Using full-wave rectifier circuit, the average steady state energy stored across 6F capacitor per 2.5s of operation was 7.4mJ that is greater by factors of 4, 2 2 from the stored energy across 1.4mF, 2.2mF & 3.3mF capacitors, respectively. The SMA cyclic heating and cooling experiment was developed to evaluate the relationship between SMA stress and SMA temperature, and to validate the hysteretic behavior of SMA actuator upon thermal loading. Sigmoidal-Weibull 4 parameter model was obtained as the best curve fitted model to the experimental SMA stress-temperature data. The test results also disclosed the hysteretic characteristic of SMA wires induced by cyclic thermal loading This confirmed the functionality of presented energy harvesting device using SMA actuators. Then, Heat trans (open full item for complete abstract)

Committee: Erik Engeberg Dr. (Advisor); Celal Batur Dr. (Committee Co-Chair); D. Dane Quinn Dr. (Committee Member); Hariharan Subramaniya I Dr. (Committee Member); Alper Buldum Dr. (Committee Member) Subjects: Automotive Engineering; Energy; Engineering; Materials Science; Mechanical Engineering; Mechanics