Bachelor of Science (BS), Ohio University, 2022, Physics

Collective rotational structures of nuclei near N = 40 have been investigated previously, but the higher spin states of 66Fe have not been studied. Here we analyze the data from an experiment conducted at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) in a projectile fragmentation reaction. New transitions in 66Fe were measured. One such transition was shown to be in coincidence with the adopted Jπ = 2+ -> 0+ and 4+ -> 2+ transitions. 65Fe and 67Co are also studied, with new transitions identified. Estimates of deformation for 66Fe are given and the angular momentum distribution from the fragmentation reaction is discussed. The data gathered will help improve upon current models of nuclear structure; further analysis including comparison to such models is necessary.

Committee: Heather Crawford (Advisor); Donal Skinner (Other); David Drabold (Other) Subjects: Nuclear Physics; Physics

Master of Science (M.S.), University of Dayton, 2024, Renewable and Clean Energy

This study presents a data-driven model designed to estimate energy savings for residential buildings, with a focus on low-income communities where energy efficiency improvements hold significant potential. The model integrates machine learning, nearest neighbor analysis, and clustering techniques to address limitations in traditional energy savings methods, which often lack the adaptability and regional specificity required for accurate predictions. Key objectives include the development of predictive models using building characteristics, refinement of savings estimates through Coefficient of Variation (CoV) analysis, and the creation of a graphical user interface (GUI) that provides accessible energy savings estimates for end-users, such as city planners and residents. The model was trained on the National Renewable Energy Laboratory (NREL) dataset and further validated through clustering and statistical analysis to ensure reliability across diverse energy-saving scenarios, including enhancements in insulation, infiltration, HVAC efficiency, and thermostat settings. Results demonstrate that clustering enhances prediction stability by filtering out high-variability data points, while CoV analysis aids in prioritizing buildings with the highest potential savings, especially in high-energy-use or low-income contexts. Findings indicate that the model effectively identifies high-impact energy efficiency measures, guiding resources toward modifications that promise the most substantial reductions in energy consumption. Although the results provide general estimates rather than precise savings values, they offer actionable insights into which building improvements are likely to be most effective, accompanied by metrics that communicate prediction reliability. The accessible GUI developed as part of this study enables end-users to retrieve address-specific savings predictions, promoting data-informed decision-making for energy efficiency improvements. This research (open full item for complete abstract)

Committee: Kevin Hallinan (Committee Chair); Erin Gibbemeyer (Committee Member); Andrew Chiasson (Committee Member) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 2021, Physics

Non-central collisions of relativistic atomic nuclei contain enormous angular momentum, $|\vec{J}|\sim\mathcal{O}(10^0-10^2\frac{\rm{TeV\cdot~fm}}{c}\approx10^3-10^5\hbar)$ in the collision energy range spanned by the capabilities of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab (BNL). The energy densities that exist in the collision interaction region are sufficient to deconfine constituent quarks from their bound nucleon states and thereby facilitate the short-lived ($\mathcal{O}(1\mathrm{fm}/c)$) formation of the so-called Quark-Gluon Plasma (QGP), to which some of the net $\vec{J}$ is transferred. The Solenoid Tracker At RHIC (STAR) is a set of detectors working in unison to reconstruct collision information, and is an indispensable tool used to study the QGP. I present here work surrounding $\vec{J}$, ranging from detector construction for STAR in order to accurately measure $\hat{J}$, experimental analysis of phenomena driven by $\vec{J}$ usig the STAR detector, and theoretical calculations involving the direction of $\vec{J}$ affected by event-by-event fluctuations. The ``Event-Plane Detector" (EPD), after years of prototyping and design, was largely constructed at Ohio State University in 2017-2018 and officially replaced its predecessor, the Beam Beam Counter (BBC), at STAR. While similar detectors have been constructed, including the BBC, unique challenges were faced in the construction of the EPD. Due to many factors, including careful construction, the EPD's performance was and remains phenomenal, providing experimentalists in the STAR collaboration with far-improved resolution on $\hat{J}$. The use of the EPD was essential for drastically reducing the statistical uncertainties on a number of analyses, including the spin alignment of $\Lambda$ hyperons with $\hat{J}$, $\PLambda$. In this thesis is detailed the process of extracting the $\vec{J}$-driven $\PLambda$ at the relatively low center-of-momentum nucleon-nucleon col (open full item for complete abstract)

Committee: Michael Lisa (Advisor); Ulrich Heinz (Committee Member); Thomas Humanic (Committee Member); Michael Poirier (Committee Member) Subjects: Nuclear Physics; Physics

Doctor of Philosophy, University of Akron, 2019, Electrical Engineering

This dissertation provides an in-depth analysis of information theoretic aspects of next-generation energy-efficient wireless networks taking into consideration important impairments which are prevalent in such networks. The main focus is on the design of optimal signaling schemes and the calculation of the information theoretical limits of non-Gaussian channels and channels under non-linear quantization functions. In the first part we focus on the optimal signaling schemes and energy efficiency of point-to-point and multi-user communication channels under Gaussian-mixture aggregate interference. Because there does not exist any explicit expression of the mutual information for such channels, we face new challenges and the novelty in technical derivations and analysis makes our work stand out from the current state-of-the-art. The second part of this dissertation investigates the capacity region and detailed characterizations of capacity-achieving signaling schemes of a Multiple-Access Channel with two mobile users communicating to a base station equipped with 1-bit quantizers. Building upon these results, we demonstrate that any Π/2 circular symmetric input distribution having a constant amplitude is sum-capacity achieving. As a result, we establish the sum-capacity in closed-form.

Committee: Nghi Tran PhD (Advisor); Nguyen Truyen PhD (Committee Member); Bahrami Hamid PhD (Committee Member); Sastry Shiva PhD (Committee Member); Farhad Siamak PhD (Committee Member) Subjects: Electrical Engineering

Master of Science, The Ohio State University, 2015, Allied Medical Professions

The female athlete triad and the recent introduction of the relative energy deficiency in sports (REDS) classifications define the negative consequences of the relationship between energy availability and overall physical health in athletes. The current triad paradigm considers the spectrum of energy availability of the athlete that can range between appropriate exercise with adequate fueling to more extreme weight loss methods such as restriction and over-exercising that may be associated with low energy availability (LEA) or a formal eating disorder. Eating disorders are typically characterized by restriction in dietary intake affecting total calories, macronutrients, and micronutrients consumed. In order to determine the diet composition, diet records and food frequency questionnaires are the two most common recording methods. However, their reliability and ability to be replicated in the female athlete population remains unclear. Furthermore, the macronutrient distribution of the female athlete's diet has been given little attention to establish if this distribution plays a role in the presence of LEA and skews total energy intake found in diet records. This study assessed the validity and reliability of diet records compared with an on-line food frequency questionnaire in recreational female runners. The two dietary tools used, three day food record analyzed by ESHA food processor and Vioscreen FFQ, produced similar intakes for calories, protein, and fat with correlations of .500, .59, .366, and .468 respectively, but ESHA consistently estimated calories and macronutrients higher compared to Vioscreen. In describing macronutrient contribution to the difference between the two tools, fat contributed 71.1% of the variability to the difference in caloric intake with carbohydrate contributing 22.1% and protein 2.1%. The macronutrient distribution from these two tools was then compared to current guidelines and assessed within the LEA framework. Of the (open full item for complete abstract)

Committee: Jackie Buell (Committee Chair); Marcia Nahikian-Nelms (Committee Member); Taylor Christopher (Committee Member) Subjects: Nutrition

Doctor of Philosophy, The Ohio State University, 2024, Physics

This work has demonstrated the evidence that High Harmonic Generation (HHG) from liquid phase is modified by the local environment creating spectral features such as a wavelength independent cutoff and a suppression of individual harmonics. This also implies liquid HHG may be a powerful took in probing liquid structure and studying low energy electron scattering in liquids. During the HHG process in a liquid environment, there are low energy electrons traveling from their parent ion on similar length scales as the intermolecular distances with a high probability to interact with their environment via elastic scattering. These electron trajectories, being only short trajectories, then have a one-to-one mapping to emitted photon energy. This gives the ability to connect the local liquid structure to the observed spectra. A vacuum apparatus was designed and built for the purpose of generating and studying high harmonics from liquid phase. A wide variety of solvents were studied including water, alcohols and organic molecules such as the halogen-substituted benzene derivatives and toluene. These solvents were found to exhibit different yields and spectral features such as cutoff energy which are consistent with a electron trajectory-limited picture. The cutoff energy was found to be wavelength independent for a wavelength range of λ = 1600-3200 nm for liquid toluene, in a significant departure from gas phase HHG. In addition to pure solvents, HHG from solutions were explored where features like a suppression of an individual harmonic in the plateau region were found for different concentrations. The strongest suppression was from a solution of fluorobenzene and methanol, specifically a 9% PhF solution by mole concentration. There was a trend found that the addition of fluorine to the benzene derivative usually contributes to some form of harmonic suppression in a solution of methanol. There's evidence that the origin of the suppression is (open full item for complete abstract)

Committee: Louis DiMauro (Advisor); Jay Gupta (Committee Member); Alexandra Landsman (Committee Member); Robert Baker (Committee Member) Subjects: Physics

Doctor of Philosophy (PhD), Ohio University, 0, Physics and Astronomy (Arts and Sciences)

The production mechanisms for boron, as well as for beryllium and lithium, are hypothesized to lie outside well established standard stellar nucleosynthesis processes. Boron is thought to have been formed via Core Collapse Supernovae as well as via cosmic ray nucleosynthesis. It is an element whose astrophysical origins facilitate a glimpse into some of the more extreme astrophysical processes in the Universe. Boron's stable isotopes, 10B and 11B, have therefore been studied for some time. The single proton structure of the 11B isotope, however, is understudied. For the purpose of studying the 11B single proton structure, we measured the 10Be(p,n)10B reaction at the Edwards Accelerator Laboratory by bombarding an 85-µg/cm2-thick 10BeO target with a proton beam. Two separate techniques were used: the time-of-fight method, and a neutron counting scheme via the use of proportional counters. The diferential and angle-integrated reaction cross sections were measured in the 0.5 ≤ Ep ≤ 7.0 MeV energy range using the Swinger beamline as well as the Helium Boron-Trifuoride Giant Barrel (HeBGB) neutron detector, respectively. Swinger beamline measurements measured a 0◦ excitation function in the 2.0 ≤ Ep ≤ 7.0 MeV energy range, and resonances were observed at Ep = 2.2-2.5, 3.5, 4.5-4.7, and 5.7 MeV. Angular distributions up to 150◦ and 105◦ were measured at 2.5 and 3.5 MeV, respectively. An angle-integrated excitation function was measured in the 0.5 ≤ Ep ≤ 2.4 MeV energy range using HeBGB. Resonances were observed at Ep = 1.09 - 1.55, 1.8, and 2.4 MeV. Gamma-ray spectra were also measured via the Swinger beamline, using a LaBr3 detector. Gamma-rays corresponding to the decay of the first two excited states of 10B, as well as the first excited state of 7Li, were observed. Lastly, a new target holder for HeBGB was designed and implemented to facilitate beam collimation when bombarding the 10BeO target

Committee: Carl Brune (Advisor) Subjects: Experiments; Nuclear Physics; Physics

Master of Science in Engineering, Youngstown State University, 2022, Department of Electrical and Computer Engineering

Bluetooth Low Energy (BLE) has emerged as one of the main wireless technologies used in low-power electronics, such as wearables, beacons, and devices for the Internet of Things (IoT). BLE's energy efficiency characteristics and ease of use interface are essential features for the design of ultralow-power devices. The integration of BLE with various sensors is certainly the main aspect for the development of efficient solutions, and monitoring the power consumption of the device in all the cycles of operation is important for decisions such as advertising interval, sensor routine and data transmission. Recent work of BLE power analysis focuses on the theoretical aspects of the advertising and scanning cycles, with most results being presented in the forms of mathematical models and computer software simulations. Such models and simulations are particularly important for the understanding of the technology. However, many times they leave real applications out of scope. This thesis covers the implementation of a multi-sensor Bluetooth Low Energy system, and the study of the communication protocol regarding its power consumption and RF performance. The implementation consists of a battery powered custom Printed Circuit Board (PCB) featuring the Texas Instruments CC1352P7 as the main SoC and three different sensors capable of measuring 6 different parameters. The sensors are the BME688 from Bosch, and the ADXL343 and AD5941 from Analog Devices. The characterization process was performed using Keysight EXR Oscilloscope and 208A Spectrum Analyzer. The proposed design has dimensions of 28 mm × 35 mm. The current consumption of the implemented design with one sensor in operation is 4.1mA and 7.1mA, and 6.9 mA combined.

Committee: Frank Li PhD (Advisor); Pedro Cortes PhD (Committee Member); Vamsi Borra PhD (Committee Member) Subjects: Computer Engineering; Electrical Engineering

Master of Science (M.S.), University of Dayton, 2022, Electro-Optics

Over the past decade, the benefits of photonics over electronics such as ability to achieve high bandwidth, high interconnectivity and low latency, together with the high maturity of silicon photonics foundries has spurred robust applications in optical transceivers and in classical and quantum computing. In both application areas, silicon microring resonators (MRRs) using carrier depletion effects in p-n junctions represent the most compact optical switches manufacturable at high volume with 5.2fJ/bit power consumption. Matrix computation approaches as well wavelength-division-multiplexed modulators require several MRRs in series coupled to the silicon waveguide optical bus. Such architectures are potentially limited to ∼ 30 by the limited free-spectral range (FSR) of an individual MRR. However, with ever increasing data volumes, there is a need to process larger matrices and/or modulate more wavelengths in the telecom bands along a single silicon bus channel. Photonic crystal (PC) dielectric structures confine an optical mode to sub-micron mode volumes and have shown the potential to reach 0.1fJ switching energies. Research till date on PC devices have centered on either inline one-dimensional PC nanobeam structures or on two-dimensional PC waveguide coupled microcavity configurations. In this paper, through detailed electrical and optical simulations, we demonstrate the feasibility to achieve compact switches with 1dB insertion loss, 5dB extinction and ∼ 260aJ/bit energies in oxide-embedded bus-coupled 1D photonic crystal nanobeam platform. Resonance linewidths <0.1nm and FSR >100nm enable energy efficient computing of larger matrices with ∼200 resonators in series separated by ∼ 0.5nm wavelength over the entire C+L bands. Device architectures will be presented.

Committee: Swapnajit Chakravarty (Advisor); Partha Banerjee (Committee Member); Andrew Sarangan (Committee Member); Swapnajit Chakravarty (Committee Chair) Subjects: Engineering; Optics

MS, University of Cincinnati, 2022, Engineering and Applied Science: Civil Engineering

This objective of this research is to develop a cost-effective large-scale outdoor construction equipment tracking system. For this purpose, a detailed comparative study was conducted on the available localization technologies in the industry. The reliability and limitations of State DOTs current system for tracking construction equipment were assessed, and after identifying alternative technologies available in the market, the most optimal option was selected for developing an efficient and cost-effective tracking system. The research proposes Bluetooth Low Energy Technology, as an alternative to the GPS Technology, for developing a large-scale outdoor construction equipment tracking system using beacons, owing to its low-cost, long life, ruggedness, and ease of installment. To install the system on DOT's equipment and analyze its operation and efficiency, several field tests were conducted to optimize the proposed system's performance. The research concludes with a life-cost-benefit analysis, discusses the optimal results for system's cost and life, and gives the necessary recommendations for its implementation. In conclusion, BLE Technology is effective and economical for large scale outdoor construction equipment localization. Although it is new and advanced, the implementations and benefits of BLE technology are many but uncovered, yet, and more research is needed in this area.

Committee: Munir Nazzal Ph.D. (Committee Member); Nabil Nassif (Committee Member); Sara Khoshnevisan Ph.D. (Committee Member) Subjects: Civil Engineering

Master of Science, The Ohio State University, 2021, Computer Science and Engineering

Digital contact tracing offers significant promise to help reduce the spread of SARS-CoV-2 and other viruses. Google and Apple joined together to create the Google/Apple Exposure Notification (GAEN) framework to determine encounters with anonymous users later diagnosed COVID-19 positive. However, as GAEN lacks geospatial awareness, it is susceptible to geographically distributed replay attacks. While the replay attack is generally known, we contribute a new proof-of-concept for an easily deployed, anonymous, low-cost, crowd-sourced replay attack network by malicious actors (or far away nation-state attackers) who utilize malicious (or innocent) users' smartphones to capture and replay GAEN advertisements that drastically increase false-positive rates even in areas that otherwise exhibit low positivity rates. In response to this powerful and feasible replay attack, we introduce GAEN+, a solution that enhances GAEN with geospatial awareness while maintaining user privacy, and demonstrate its ability to effectively prevent distributed replay attacks with negligible overhead compared with the original GAEN framework.

Committee: Anish Arora (Advisor); Zhiqiang Lin (Committee Member) Subjects: Computer Science

Master of Sciences (Engineering), Case Western Reserve University, 2021, EECS - Electrical Engineering

This thesis presents an innovative cross-coupled differential drive rectifier for ultra-low power RF energy harvesting applications. Designed in a standard 65-nm complementary metal oxide semiconductor (CMOS) process, it employs dynamic threshold compensation and forward body biasing techniques to compensate for the threshold of MOS devices. A simple off-chip differential matching network is used to interface with the antenna. Post-layout simulations show that the proposed single-stage rectifier achieves a power conversion efficiency (PCE) > 10% and produces output voltage > 160 mV (at 300 kΩ load) when receiving a 2.4 GHz signal with average power of -30dBm. The measurement results show that the proposed rectifier reaches 10% PCE when receiving a 2.4 GHz signal with average power of -27dBm (at 100kΩ load). Compared to the state-of-the-art, the result shows favorable performance for low input powers (<-27 dBm) despite operating at higher frequency.

Committee: Hossein Lavasani (Advisor); Francis Merat (Committee Member); Christian Zorman (Committee Member) Subjects: Electrical Engineering

Master of Sciences, Case Western Reserve University, 2020, EECS - Computer Engineering

The internet of things (IoT) is rapidly becoming part of everyday life. The internet of things can be anything from smart assistants, or smart devices such LED light bulbs, electric outlets to widely used wireless sensor networks. Electrical devices inside any household has potential to become part of wireless mesh network where each device is monitored for their operation and electrical energy consumption. Still, monitoring electric consumption inside a household is still not actively utilized under internet of things. Majority of the houses are equipped with smart energy meters which transmit weekly or monthly power usage to electrical companies. These readings are reflected in the electric bill every month and provide very crude and irrelevant information to pinpoint energy activities in the desired `meshes' of individual rooms of any household and therefore cannot meet the growing expectation and requirements for abundance and accuracy of the data, for efficient electrical energy management. After a comprehensive survey of existing energy monitoring devices and systems, a few technologies have come across which focus either on single device or on overall household. These technologies will not be able to pinpoint every device in a household. Apart from the surface level monitoring, these devices tend to be expensive as they come with subscription and added devices for complete support. To compete with such technologies, an electric energy monitoring system is proposed. This system has three layers of software and hardware components. The first layer is sensors. These sensors make use of existing wireless sensor network mesh technology. Each sensor is a low-cost Bluetooth low energy (BLE) based module which monitors electrical devices. The second layer is gateway. The gateway acts as the middle man between sensor and the third layer which is server. Gateway grabs data from the sensors and translates it to server compatible language package and sends it to the se (open full item for complete abstract)

Committee: Philip Feng (Advisor); Christos Papachristou (Committee Member); Kenneth Loparo (Committee Member) Subjects: Computer Engineering

PHD, Kent State University, 2020, College of Arts and Sciences / School of Biomedical Sciences

With nearly 70% of Americans overweight or obese, uncovering ways to increase energy expenditure is critical for treating obesity. Skeletal muscle has a substantial capacity for increasing energy expenditure and is clinically relevant as it makes up 40% of total human body mass, accounts for 20-30% of total resting oxygen uptake, and is the primary site for glucose uptake and fatty acid oxidation. Moreover, improved muscle function and metabolism are linked to leanness. Steroidogenic factor-1 (SF-1) cells in the ventromedial hypothalamus (VMH) regulate body weight by modulating peripheral metabolism, including skeletal muscle metabolism. Interestingly, VMH SF-1 cells are also critical mediators of behavioral responses to predator threat. We have previously shown that predator odor exposure to rats causes a rapid and robust increase in skeletal muscle thermogenesis that is associated with increased physical activity, energy expenditure, and weight loss. VMH SF-1 cells are a likely mediator of these predator odor-induced metabolic responses, but the mechanisms of this dual-processing role are unknown. To explore the underlying mechanisms, we altered VMH SF-1 activity using SF-1-specific designer receptors exclusively activated by designer drugs (DREADDs). We also performed RNA-sequencing and qPCR to reveal how predator odor exposure alters the VMH transcriptome. We found that VMH SF-1 activity is necessary for the muscle thermogenic effect of predator odor when controlling for physical activity. We also found that predator odor induced thermogenesis is dampened in a polygenic model of obesity, but amplifying SF-1 activity partially mitigates this deficit. Further, our gene expression assays revealed that predator odor exposure results in rapid changes in inflammation, oxidative stress, and synaptic plasticity within the VMH. Taken together, our findings show that VMH SF-1 cells mediate the skeletal muscle thermogenic response to predator odor and alter the locomotor e (open full item for complete abstract)

Committee: Colleen Novak (Advisor); John Johnson (Committee Member); Jasnow Aaron (Committee Member); Barkley Jacob (Committee Member); Frazier Gail (Committee Member) Subjects: Biomedical Research; Cellular Biology; Molecular Biology; Neurosciences

Master of Sciences, Case Western Reserve University, 2020, EECS - Electrical Engineering

This thesis reports on the design and development of a Bluetooth Low Energy (BLE)-enabled neural microsystem suitable for activity-dependent stimulation applications in non-human primate models. The resulting microsystem is fabricated in all-rigid and rigid-flex substrates, operates autonomously from a 3.6V, 1.6A.h., lithium-ion battery, weighs approximately 48 grams (including the battery), consumes ~618μW under nominal operation, and is housed within a custom 3D-printed resin enclosure. An end-to-end BLE-enabled wireless communication protocol is developed to allow the user to wirelessly program the ICMS ASIC, measure stimulation rate, estimate electrode site impedance, and measure system power supply levels from a user base station. Comprehensive bench-top and in vitro tests demonstrate successful operation of the implemented hardware, software, and firmware. Additionally, initial results from in vivo experiments in awake squirrel monkeys are reported.

Committee: Pedram Mohseni (Committee Chair); Francis Merat (Committee Member); Soumyajit Mandal (Committee Member); Randolph Nudo (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2019, Physics

In crystalline materials, the symmetry of the crystal lattice imposes strict conditions on the observable properties of the material. These symmetry restricted conditions can be, in turn, probed by light via the electromagnetic interaction. Studying the electromagnetic excitations in solids can reveal many fundamental properties of these systems. A quick introduction and guide to symmetry in solids will be given, with an emphasis on how it can be used to interpret spectroscopic measurements. The measurement techniques used will also be described. Time domain Terahertz spectroscopy (TDTS) is the main technique used in this dissertation. Important experimental considerations pertaining to the construction of the THz spectrometer will be given. In the multiferroic Sr_2 FeSi_2O_7, we found multiple excitations in the few meV energy scale (THz), in the material's paramagnetic phase. Measurements with varying temperature and magnetic field revealed that these excitations are both electric and magnetic dipole active. By considering the ground state of the Fe 2+ magnetic ion in Sr 2 FeSi 2 O 7 , we concluded that our observation is coming from the spin-orbital coupled states of the ion. This realization demonstrated that spin-orbit coupling plays a crucial role in these exotic materials. Interestingly, these spin-orbital THz excitations persist into the magnetically ordered phase. The single-ion picture of the paramagnetic phase needs to be expanded theoretically to explain our observations. CaFe_2O_4 orders antiferromagnetically below ~ 200 K. Two co-existing magnetic structures (A and B phase) have been measured previously by neutron diffraction. The anti-phase boundaries between these two phases have been proposed to be the cause of the quantized magnetic excitations (magnons) measured by an inelastic neutron scattering study. We measured two antiferromagnetic resonances (magnons) with TDTS. Our observation can be explained by the orthorhombic crystal anisotropy of CaF (open full item for complete abstract)

Committee: Rolando Valdes Aguilar (Advisor); P. Chris Hammel (Committee Member); Nandini Trivedi (Committee Member); Douglass Schumacher (Committee Member) Subjects: Physics

Master of Science (MS), Wright State University, 2018, Physics

The field of plasma confinement and path toward achieving thermonuclear fusion started with experimental devices like tokamak and has evolved into other more complex variants of magnetic plasma confinement such as stellarator and spherical-tokamaks. As the plasma confinement machines advance towards higher temperature and plasma density (thermonuclear fusion conditions) the role and nature of plasma-wall interaction such as possible edge plasma regimes, particle recycling at the walls and its consequence for erosion, migration and re-deposition of wall material and impurity generation, transport and radiation as well as issues of particle exhaust continues to be a dominant limiting factor due to the close proximity of the wall. The selection of optimal wall-material for the plasma-wall components is a complex process, and till date, it continues to be an important and challenging area in the field of study of plasma-wall interaction. Various metals, ceramics or graphites with desirable response to severe thermal loads and varying mechanical properties towards elastic deformation, plastic deformation, fatigue, and toughness have been proposed. Sputtering and wall-erosion which results in plasma contamination is an important determining factor for wall-material selection. Tungsten is considered as a possible candidate for plasma facing material because of its high thermal conductivity, low hydrogen retention, high atomic mass (high-Z), and, high melting point. In both, limiter and divertor configurations there is substantial recycling of particles on the wall due to continuous bombardment of wall material by both charged and neutral particles. Experimental studies have shown that the light particle species such as hydrogen and helium are able to penetrate into the tungsten wall and substantial trapping of helium in tungsten has been observed. Among other issues, blistering, fuzz formation, tritium retention, surface roughening, and intergranular embrittlement are ma (open full item for complete abstract)

Committee: Amit Sharma Ph.D. (Advisor); Brent Foy Ph.D. (Committee Member); Gregory Kozlowski Ph.D. (Committee Member) Subjects: Physics

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

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

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

Master of Science (MS), Ohio University, 2017, Electrical Engineering & Computer Science (Engineering and Technology)

Body Area Networks are beneficial in many applications including fitness tracking and remote healthcare monitoring. This thesis discusses system enhancements to the award-winning Ohio University Body Area Network system which senses heart rate, integrates an inertial measurement unit, and measures ambient temperature. An upgraded ARM-based Nordic microprocessor was implemented to collect and process biometric sensor data and utilize low-energy Bluetooth (BLE) to transmit data via a Bluetooth antenna. Data is received on an updated Android application running on a handheld Nexus 5 Smartphone. Power received measurements were performed to compare the Baseline and Enhanced systems using several Bluetooth antenna solutions including an e-textile spiral antenna, a traditional inset-fed patch antenna, and a printed monopole antenna.

Committee: Chris Bartone (Advisor); Savas Kaya (Committee Member); Maarten Uijt De Haag (Committee Member); David Drozek (Committee Member) Subjects: Computer Engineering; Electrical Engineering

Master of Science in Mechanical Engineering (MSME), Wright State University, 2017, Mechanical Engineering

This research focuses on the energy absorption capability of additively manufactured or 3D printed polymer lattice structures of different configurations. The Body Centered Cubic (BCC) lattice structure is currently being investigated by researchers for energy absorption applications. For this thesis, the BCC structure is modified by adding vertical bars in different arrangements to create three additional configurations. Four designs or sets of the lattice structure are selected for comparison including BCC, BCC with vertical bars added to all nodes (BCCV), BCC with vertical bars added to alternate nodes (BCCA), and BCC with gradient arrangements of vertical bars (BCCG). Both experimental and finite element modeling approaches are used to understand the load-displacement as well as energy absorption behavior of all four configurations under both quasi- static compression and low-velocity impact loadings. Once designed in SolidWorks, all four sets of samples were prepared using Acrylonitrile Butadiene Styrene (ABS) polymer material on a Stratasys uPrint 3D printer. The Instron universal testing machine was used for the quasi-static loading test whereas an in-house built ASTM Standard D7136 drop tester was used to capture the impact response. For impact samples, sandwich panels were fabricated using the 3D printed ABS lattice core structures. In this case, four Kevlar face sheets were attached to the lattice core structure using a two-part epoxy adhesive. The absorbed energy was found by integrating the area under the load-displacement curve for both compression and impact tests. To interpret the results, Specific Energy Absorption (SEA) that is the absorbed energy over the mass, should be considered. Moreover, the investigation of the SEA was also performed using Finite Element Analysis (FEA) for comparison. ANSYS Workbench was used to predict the behavior of the lattice structures under compression load. However, Abaqus Dynamic Explicit was used to capture (open full item for complete abstract)

Committee: Ahsan Mian Ph.D. (Advisor); Raghavan Srinivasan Ph.D. (Committee Member); Maher Amer Ph.D. (Committee Member) Subjects: Aerospace Engineering; Design; Mechanical Engineering; Mechanics