Doctor of Philosophy (PhD), Wright State University, 2023, Engineering PhD

Blood flow dynamics plays a critical role in maintaining tissue health, as it delivers nutrients and oxygen while removing waste products. It is especially important when there is a disruption in cerebral autoregulation due to trauma, which can induce ischemia or hyperemia and can lead to secondary brain injury. Thus, there is a need for noninvasive techniques that can allow continuous monitoring of blood flow during intervention. Optical techniques have become increasingly practical for measuring blood flow due to their non-invasive, continuous, and relatively lower-cost nature. This research focused on developing a low-cost, scalable optical technique for measuring blood flow by implementing speckle contrast optical spectroscopy using a fiber-camera-based approach. This technique is particularly well-suited for measuring blood flow in deep tissues, such as the brain, which is challenging to access using traditional optical methods. A two-channel continuous wave speckle contrast optical spectroscopy device was developed, and the device was rigorously tested using phantoms. Then, it is applied to monitor blood flow changes in the brain following traumatic brain injury (TBI) in mice. The results indicate that trauma-induced significant blood flow decreases consistent with the recent literature. Overall, this approach provides noninvasive continuous measurements of blood flow in preclinical models such as traumatic brain injury.

Committee: Ulas Sunar Ph.D. (Advisor); Tarun Goswami Ph.D. (Committee Member); Keiichiro Susuki Ph.D. (Committee Member); Robert Lober M.D., Ph.D. (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Biophysics; Engineering; Optics

PhD, University of Cincinnati, 2020, Arts and Sciences: Geography

The saguaro (Carnegiea gigantea [Engelm.] Britton and Rose) is a long-lived, columnar cactus and a keystone species in Sonoran Desert ecology. The saguaro is an iconic symbol of the U.S. American Southwest with a long and deep ethnobotanical history. In the northern Sonoran Desert, saguaro research is focused on two primary domains: the influence of climate on growth and reproduction and the anthropogenic impacts of human activity on the species and to the landscape. Saguaro growth and establishment are strongly influenced by the timing and amount of summer precipitation, and winter minimum temperature is an additional control. Anthropogenic historic land uses in the Southwest significantly altered ecosystem function and vegetation community type and structure throughout the region. Understanding the changes in community form and process provides a basis for ecological restoration. Saguaro National Park (SNP) is comprised of two districts on the east and west sides of Tucson, Arizona, and contains historic plots that have been monitored for more than 80 years. This dissertation utilizes some of the oldest demographic data available for the species to examine the physical geographic, anthropogenic, and climatic conditions and processes that affect saguaro growth and establishment at multiple spatial and temporal scales. The stratified plot-based approach utilized in this dissertation captures the response of the saguaro to climatic and landscape settings in different vegetational communities and across gradients of slope, aspect, and elevation within SNP. Additionally, much of the data collected for this dissertation are publicly available and serve as the latest snapshot in time of the saguaro population for the work of a next generation of researchers and public land stewards. This dissertation is presented in journal article format. Chapter 2 analyzes the demographic change over 75 years within a population of saguaros in an area of SNP that has a legacy o (open full item for complete abstract)

Committee: Nicholas Dunning Ph.D. (Committee Chair); Richard Beck Ph.D. (Committee Member); Kevin Raleigh Ph.D. (Committee Member); Vernon Scarborough Ph.D. (Committee Member); Susanna Tong Ph.D. (Committee Member) Subjects: Geography

Master of Science in Biomedical Engineering (MSBME), Wright State University, 2019, Biomedical Engineering

Neurovascular coupling is an important concept that indicates the direct link between neuronal electrical firing with the vascular hemodynamic changes. Functional Near Infrared Spectroscopy (fNIRS) can measure changes in cerebral vascular parameters of oxy-hemoglobin and deoxyhemoglobin concentrations and thus can provide neuronal activity through neurovascular coupling. Currently many commercial fNIRS devices are available, but they are limited by the number of channels (usually having only 8 detectors), which can limit the sensitivity, contrast, and resolution of imaging. High-density imaging can improve sensitivity, contrast, and resolution by providing many measurements and averaging the signals originating from the target cerebral focus area compared to background tissue. Here a multi-channel, low-cost, high-density imaging system based on scientific CMOS (Complementary Metal-Oxide-Semiconductor) detector will be presented. The CMOS camera is fiber-coupled such that on one end fibers are focused on the pixels on the CMOS camera, which allows individual pixels (or binned sub-pixels) to act as detectors, while the other end of the fibers can be positioned on a wearable optical probe. After the device details, I will show the device validation using a series of the dynamic flow phantom experiments mimicking the brain activation and finally human motor cortex experiments (finger tapping experiments). The results demonstrate that this system can obtain high-density data sets with higher contrast and resolution. This wearable, high-density optical neuroimaging technology is expected to find many applications including pediatric neuroimaging at clinics and assessing human cognitive performance.

Committee: Ulas Sunar Ph.D. (Advisor); Keiichiro Susuki Ph.D. (Committee Member); Tarun Goswami Ph.D. (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Engineering; Optics

PhD, University of Cincinnati, 2003, Engineering : Civil Engineering

Fiber Reinforced Polymers (FRP) have emerged from extremely expensive materials that were only used for high-end applications to a more common and more affordable product that becomes increasingly indispensable for our daily lives. A variety of fields of technology has taken advantage of the material properties of FRPs that are characterized by their linear elastic behavior, excellent strength to weight ratio, and non-corrosiveness. One such discipline is the construction industry where FRPs are seen as an alternative to traditional construction materials and technology. During the past 45 months, a unique research project at the University of Cincinnati investigated the long-term performance of multiple FRP panel systems as decks on a large bridge. The project involved the longest bridge in the United States that had been equipped with FRP panels, and the only one which had panels from multiple manufacturers. Such characteristics set the presented research project on the leading frontier for applications of FRP materials in infrastructure. The focus of the research was to investigate the performance of different FRP deck systems in contrast to the original standard reinforced concrete decks. Moreover, the research is unique as the performance of individual FRP systems under identical environmental and ambient conditions are compared. The short- and long-term performance of multiple FRP deck systems was investigated during several controlled truck load tests and using a remote long-term monitoring response system. The field data were complemented by a multitude of visual inspections, and destructive and non-destructive laboratory tests. The sheer size and number of individual panels provided a platform to detect design, detailing, and construction issues for FRP deck systems that had not been detected in previous projects. Based on the findings of the reported research, a number of recommendations for design, detailing, and construction techniques are made to enhanc (open full item for complete abstract)

Committee: Dr. Bahram Shahrooz (Advisor) Subjects: Engineering, Civil

Master of Science in Civil Engineering, University of Toledo, 2011, College of Engineering

The Veterans' Glass City Skyway (VGCS) is a cable-stayed bridge. It replaced an old drawbridge that carried I-280 over the Maumee River. The VGCS was designed by the FIGG Engineering Group. The structure is a prestressed, post-tensioned segmental concrete cable stay bridge with a total length of 8800 feet. The bridge carries three traffic lanes of each bound and the surface of the road above the river reaches to 130 feet (40 m). This cable-stayed type bridge is a 1,225-feet cable stay span with a single plane of stay and a single pylon. The Ohio Department of Transportation (ODOT) contracted the University Research Team (URT) composed of faculty and students from the University of Toledo and the University of Cincinnati to instrument the main span of the VGCS throughout construction and service life. VGCS began construction in the spring of 2001 and was opened to traffic on June 24, 2007. 128 strain gages were installed in four segments which were selected to be instrumented when the segments were cast. These health monitoring gages can measure the value of strain and temperature at each section and data from the strain gages can be collected by a data acquisition system. This thesis is focus on the long-term behavior of VGCS during construction and service life. Experimental stresses derived from the strain data will be compared with analytical stresses at each instrumented segment. Following the AASHTO Bridge Evaluation Manual, the experimental inventory load rating will be calculated and compared with the analytical load rating. The purpose of this research is to establish the baseline for evaluating the structural health of VGCS by experimental load rating and the initial assessment of long-term stresses. Overall, comparison between experimental stress time history line and analytical stress time history line verify the behavior of VGCS performed as expect for a long-term monitoring. And inventory load rating for concrete describes the structure health of V (open full item for complete abstract)

Committee: Douglas Nims PhD (Committee Chair); Brian Randolph PhD (Committee Member); Mark Pickett PhD (Committee Member) Subjects: Civil Engineering

Master of Science (MS), Ohio University, 2012, Environmental and Plant Biology (Arts and Sciences)

Documenting change in the composition and structure of forest communities is important for understanding the distribution and abundances of natural resources, carbon pools, and species. Here, results are presented from the second sampling effort at Dysart Woods, an old-growth, mixed-mesophytic remnant tract in southeastern Ohio. In 2011, trees, saplings, shrubs, herbs, and soils were sampled in permanent plots established in 1996, allowing a direct fifteen–year comparison. Mortality and recruitment rates revealed that while most species at Dysart Woods are decreasing in abundance, sugar maple and American beech are rapidly increasing in importance, as is the invasive Alliaria petiolata. This shift in composition may be due to beech and sugar maple showing little negative responses to neighbors, and/or reflect increasing pressures that old-growth forests face from invasives. Such findings have considerable implications for the future of Dysart Woods, and developing appropriate management techniques may be required to preserve its integrity.

Committee: Brian McCarthy PhD (Advisor); Glenn Matlack PhD (Committee Member); Jared DeForest PhD (Committee Member) Subjects: Botany; Ecology; Forestry