Master of Science, Miami University, 2022, Physics

Atoms confined in a dissipative three dimensional lin⊥lin optical lattice randomly diffuse in all directions, however, illumination by a weak probe beam modulates the lattice which can lead to a directed ratcheting of some atoms in a direction perpendicular to probe propagation. We determine whether this directed ratcheting, referred to as Brillouin propagation, arises from a mechanical resonance between the probe modulation frequency and oscillation frequency of the atoms confined in the wells, or, from a velocity-matching condition where the speed of the probe modulation rippling through the lattice matches the average speed of the oscillating atoms. We emphasize that a probe propagating along a symmetry axis of the lattice cannot resolve the issue as the mechanical resonance and velocity-matching conditions are satisfied simultaneously. We misaligned our probe from a lattice symmetry axis to create a situation where the condition for velocity-matching is exclusively satisfied and Brillouin propagation still occurs, thus proving the cause of this form of cold atom ratchet. The spectral signatures for Brillouin propagation in the case of an off-axis probe are investigated as a function of off-axis angle and lattice well-depth. Our data agrees well with theoretical predictions. Residual discrepancies between theory and data are analyzed.

Doctor of Philosophy (Ph.D.), University of Dayton, 2016, Electrical Engineering

In recent years, considerable research has been carried out relative to the electromagnetic (EM) propagation and refraction characteristics in metamaterials with emphasis on the origins of negative refractive index. Negative refractive index may be introduced in metamaterials via different methods; one such is the condition whereby the Poynting vector of the EM wave is in opposition to the group velocity in the material. Alternatively, negative refractive index also occurs when the group and phase velocities in the medium are in opposition. The latter phenomenon has been investigated extensively in the literature, including recent work involving chiral metamaterials with material dispersion up to the first order. This dissertation examines the possible emergence of negative refractive index in dispersive chiral (lossless and lossy) metamaterials with material dispersion up to the first and second order. The motivation of this work has two parts- the first part is to determine if using second- as opposed to first-order material dispersion may lead to more practically realizable negative index behavior in the lossless material; the second part is to determine if including the conductive loss to the medium with material dispersion up to the first order (a feature likely to be present in most realistic cases; conductive losses in such materials as nanometals, or dielectric losses in a variety of other nanomaterials, such as lithium niobate and Sic+Ag) may lead to the emergence of negative index. This dissertation investigates the above problems (with the exception of lossy dielectrics, the determination of which is currently ongoing) by using spectral and phasor plane-wave based analytical approaches as well as alternative analysis incorporating practical physical models into the electromagnetic equations. In this work, a spectral approach combined with slowly time-varying phasor analysis is applied leading to the derivation of EM phase and group velocities analytica (open full item for complete abstract)

B.S. in Exercise Science, University of Toledo, 2009, Exercise Science

The purpose of this study is to examine the influence of training in fast pitched softball on the developmental process used in two-handed catching in college age females. The subjects will consist of females ranging in ages from 18 to 24 who have either participated in at least three years of varsity level softball, or have no previous experience in softball. The participants will attempt to catch a ball three times as warm up and then again five times in three different locations. Subjects will be recorded with two standard digital video cameras in the frontal and saggital plane as well as with an eight camera 3-D video system. By examining their reactions during their catches, the differences in hand velocity and acceleration while catching will be calculated and analyzed between the two groups. Differences in body movement while catching will also be recorded and studied to help define common differences between the two groups. There is little research in the field of catching, especially when comparing and contrasting trained and untrained females.

Doctor of Philosophy, The Ohio State University, 2006, Materials Science and Engineering

High velocity forming methods successfully address problems faced in conventional forming techniques. They can be effectively used for forming metals with low formability like aluminum alloys and high strength steel. They can be instrumental is manufacturing of lighter vehicles with higher fuel efficiency. Electromagnetic forming (EMF) is an HVF method that is gaining wide acceptance due to its advantages and scope for commercialization. A number of experimental studies were carried out with EMF with the main goal of exploring fundamentals about material formability at high velocities, which can be used to establish practical design guidelines and to make models of high velocity formability. Thus the main factors that influence high velocity formability – inertia / size effects; changes in constitutive behavior; impact; and dynamic failure modes, were studied mainly with experiments. The role of changes in constitutive behavior in improving formability was studied from existing studies and new theoretical studies involving High velocity Forming Limit Diagram (FLD) and through solving an inverse problem of ring expansion. Tube free-expansion experiments were carried out to demonstrate enhanced metal formability even in the absence of die impact. To further establish the significance of inertia, electromagnetic ring free-expansion experiments with rings of different aspect ratios were carried out. The results clearly demonstrated the influence of sample aspect ratio (dimensions) and hence inertia on high velocity formability. Die impact experiments were carried out with tubes and rings to show the beneficial influence of die arrest of a moving sample. It was revealed that die impact in an appropriate range of velocities can significantly suppress failure and reduce the number of tears and fractures in the samples. Further a new mode of failure in die impacted samples, spall-like dynamic rupture was observed, which had characteristics similar to classic spall failure. (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2005, Chemical Engineering

Bubble columns are widely used as multiphase reactors in chemical industries due to many advantages. The transport behavior in these systems is complex and a comprehensive knowledge of the transport phenomena, including hydrodynamics and turbulence properties are required. The hydrodynamics in a high pressure bubble column is experimentally investigated. The liquid velocities are measured using a LDV (Laser Doppler velocimetry). The Reynolds stresses are obtained. The effect of the pressure on the transition of the flow regime, flow field and the Reynolds stresses are studied. Furthermore, the effects of the liquid properties on the hydrodynamics of the bubble column are discussed. The turbulence energy distributions in the bubble columns are investigated using the LDV and PIV. The energy containing ranges for the bubble-induced and shear-induced turbulence are determined from the power spectra. Experimental results indicate that the bubble-induced turbulence dominates over the shear-induced turbulence under the operating conditions. The bubble-induced turbulence includes the turbulence in the bubble wake and that from the drift velocity change. The interaction between two turbulence field can only be observed when the turbulence in both fields is strong and the interaction tends to enhance the turbulence in both fields. The liquid phase turbulence is enhanced in the presence of particles at high superficial gas velocities while it is attenuated under low superficial gas velocity conditions. A criterion based on the variation of the ratio, Ug( r )/umf is proposed to account for the effect of the solids on the liquid phase turbulence. The prediction based on this criterion matches well with the experimental results. The behavior of a 6 mm mesobubble in an acoustic standing wave field is examined both experimentally and numerically. The acoustic standing waves at 16 kHz and 20 kHz are generated using two Nickel magnetostrictive transducers. The bubble rise velocity is (open full item for complete abstract)

Doctor of Philosophy (PhD), Ohio University, 1994, Chemical Engineering (Engineering)

This study involves an experimental and theoretical investigation of slug flow in two phase gas-liquid mixtures. Water and an oil of viscosity 15 cP were used for the liquid phase and carbon dioxide was used for the gas phase. Flow in a 75 mm I.D., 10 m long acrylic pipeline system is studied. The techniques utilize digital image analysis and computational fluid dynamics. Flow is recorded on video by S-VHS cameras, using an audio-visual mixer. The image is then digitized frame-by-frame and analyzed on a SGI TMworkstation. Detailed slug characteristics including, liquid film heights, slug translational velocity, mixing length, slug length, axial and radial void distribution, and instantaneous velocity profiles are obtained. It is seen that slug characteristics are strongly influenced by the Film Froude Number ahead of the slug. The gas is released into the slug body in the form of pulses whose frequency increases with Froude number. The hydrodynamic boundary layer is destroyed at the slug front but begins to redevelop in the mixing zone. It becomes fully developed at the end of the mixing zone and the one-seventh power law shape is applicable. The length of the mixing zone is directly proportional to the Film Froude Number. At the end of the mixing zone, the gas tends to move towards the top of the pipe and the void fraction distribution tends towards a steady profile. The slug translational velocity is described using a drift velocity model. A Froude Number for the slug is defined, utilizing the equivalent pressure head. The variation of the Froude Number in the slug is then tracked at different distances in the slug. The slug tail occurs as the Froude Number tends to unity. A model is developed to estimate the slug length. Agreement with experimental data is good. The model also closely predicts the data of other researchers.

Master of Science in Mechanical Engineering, Cleveland State University, 2007, Fenn College of Engineering

This project entails a study of a wind energy recovery system that utilizes a unique three-dimensional spiral structure to amplify wind speed and direct it toward pluralities of turbines. The system is comprised of an outer spiral shell, internal support structure, turbines, and mechanisms for positioning the turbines to face the prevailing wind. Computational Fluid Dynamics (CFD) analyses were conducted to determine the wind speed amplification factors as a result of a simulated wind flow around the spiral structure. To ensure accuracy of the results, state of the art CFD techniques were applied using Gambit 2.2.30 and Fluent 6.2.16. Specifically, wind speed amplification factors were determined for 25ft and 30ft radius spiral shells. The velocity profiles of the wind flow around both spiral structures were obtained under a postulated 10mph wind speed. This resulted in a turbulent flow with a Reynolds number of 5,596,819. All analyses were run using “standard k-ε” turbulence model with the “near wall treatment” option “standard wall function”. A “y+” value of 50 was held constant in all vi simulations. The affect of the grid size on the accuracy of the results was examined. Convergence criterion was satisfied in each case. The 25ft radius spiral structure yielded an average velocity amplification factor of 1.524; while the 30ft radius resulted in an average amplification factor of 1.539. This particular information can help the designer of the system to select an appropriate overall shell size based not only on the mechanical efficiency, but also considering the cost and economical factors.

Master of Science, University of Akron, 2025, Mechanical Engineering

This study investigates the effect of cohesive properties on the impact behavior of hybrid sandwich composites through finite element analysis (FEA) validated with experimental data. Two hybrid configurations, GC (GFRP outer layers) and CG (CFRP outer layers), were analyzed under varying cohesive strength, stiffness, and fracture energy, using Hashin and Strain-Based (SB) failure criteria. The results demonstrate that SB provides better agreement with experiments, particularly in capturing progressive failure and post-impact deformation, while Hashin overpredicts peak force and delays failure initiation. The findings reveal that cohesive strength primarily governs peak force and permanent deformation, while fracture energy significantly influences energy dissipation. Additionally, stacking sequence plays a crucial role, with CFRP-dominant configurations (CG) absorbing more energy, whereas alternating hybrid layups (GCGC, CGCG) improve load distribution and reduce residual damage. These insights provide guidelines for optimizing cohesive properties and stacking sequences to enhance the impact resistance of hybrid composites for aerospace, naval, and industrial applications.

MS, University of Cincinnati, 2024, Engineering and Applied Science: Mechanical Engineering

Ultrasonic metamaterials enable new possibilities for controlling acoustic waves in ultrasound imaging and diagnostic systems, yet practical realizations are limited to the sub-MHz frequency range and suffer from high attenuation levels. This thesis introduces a new approach to design metamaterials for frequencies up to 5 MHz using accessible and cost-effective Fused Deposition Modeling (FDM) 3D printing technique. In this approach, closely packed individual FDM strands and the tiny air gaps formed between them represent the repeating unit cell of the material. The unit cell's ultrasonic properties are programmed by controlling the strand and gap shapes by adjusting FDM process settings, such as infill density and layer height. A numerical analysis of the unit cell geometry predicts the ultrasonic behavior of the metamaterials, enabling optimization-based design of ultrasonic devices, such as lenses and delay lines. Experimental validations show that Polylactic Acid (PLA)-based metamaterials exhibit lower attenuation across 0.5 to 2.5 MHz compared to state-of-the-art 3D-printed materials at a fraction of the cost. These findings highlight FDM's suitability for scalable design of next-gen biomedical imaging, SONAR, and structural health monitoring ultrasonic systems.

Master of Science, The Ohio State University, 2007, Graduate School

Doctor of Philosophy, The Ohio State University, 2024, Welding Engineering

This research focuses on the non-destructive characterization of microstructures in Grade 91 (9Cr-1Mo-V) and Grade 92 (Fe-9Cr-2W-0.5Mo) steel welds. These alloys are creep strength-enhanced ferritic (CSEF) steels commonly used in fossil-fuel-fired and nuclear power plants. The weld integrity of these two steels is crucial for power plants' safe and reliable operations. Two welding processes, cold metal transfer (CMT) and flux-cored arc welding (FCAW), were investigated for the Grade 91 steel weld test samples. For the Grade 92 weld samples, three different heat inputs (low, medium, and high) of gas tungsten arc welding (GTAW) were utilized to replicate traditional field welding processes. The non-destructive evaluation (NDE) method used for this research was immersion ultrasonic testing (UT). Using a newly patented micro-resolution ultrasonic imaging methodology specifically designed to operate in the through-transmission configuration. A 20 MHz focused probe with an ultrasonic beam focal diameter between 250-300 μm was used as the transmitter. As the receiver, a laser vibrometer with a 6-10 μm beam diameter was used to produce highly resolved ultrasonic images with longitudinal and mode-converted shear waves. Based on the micro-resolution ultrasonic C-scan images obtained during this investigation, three microstructural regions, such as weld metal (WM), heat-affected zone (HAZ), and base metal (BM), were clearly identifiable. Various levels of ultrasonic amplitudes distributed over the three regions were correlated with electron beam backscattered diffraction (EBSD) images using grain size, grain boundaries, and dislocation densities. The results showed that areas with relatively higher ultrasonic amplitude levels were associated with smaller grains and higher dislocation densities, while areas with lower amplitude levels were associated with larger grains and lower dislocation densities. In addition, ultrasonic velocity data obtained across the three differ (open full item for complete abstract)

Doctor of Philosophy, Miami University, 2024, Biology

This dissertation is structured into five chapters. Chapter I: I provide a general introduction to my dissertation, primarily introducing the different influences on intraspecific variation and providing a background on local adaptation. Chapter II: I investigate the effects of environmental conditions and demographic history on populations of desert horned lizards (Phrynosoma platyrhinos). I evaluate the demographic history of P. platyrhinos and identify signatures of selection associated with climate, which may be indicative of local adaptation. I then link signatures of selection to genes and functional genomic elements. Chapter III: I explore the influence of environmental heterogeneity on intraspecific variation of the chisel-toothed kangaroo rat (Dipodomys microps). I discover signals of selection associated with both climate and vegetation. I also find evidence that selective pressures likely vary across the species distribution and develop a permutation test to identify populations that possess more putatively adaptive alleles than expected by chance. I also link signals of selection to genes and biological functions that may be related to previously identified morphological differences between populations. Chapter IV: I perform a meta-analysis to understand general patterns of putative local adaptation in terrestrial chordates. I use previously published datasets and analyze them using a common framework to test theoretical predictions regarding the relationship between environmental and demographic factors and signals of selection. I find that signals of selection follow theoretical predictions, and, importantly, find that constant variation is an important driver of signals of selection. Chapter V: I provide conclusions and future directions from my results.

Master of Science, Miami University, 2024, Mechanical and Manufacturing Engineering

The friction and wear properties of bilayer graphene on silicon substrate with diamond atomic force microscope tip were investigated using molecular dynamic simulation with three independent variables of tip velocity, temperature, and normal load. Based on isolated experimental results, it is determined that graphene friction is velocity, temperature, and normal load dependent. Velocity and normal load increase lead to positive friction correlations while temperature increase leads to negative friction correlations, thus leaving the mechanism to be determined. Combined studies reveal similar results, with each variable maintaining its isolated effect in chorus with the other utilized. Upon obtaining the contact area from these experiments it is evident that velocity and temperature change do not hold direct bearing on the contact area, rather that it is the normal load and size of the sliding surfaces that can fluctuate both contact area and friction in tandem. Hence, the mechanism with respect to velocity and temperature dependence of graphene friction is determined to be variation in interatomic potentials associated with interatomic interactions. Varying the contact area can increase or decrease the quantity of atoms in contact, therefore also having an impact on graphene friction.

Master of Science in Computer Engineering, University of Dayton, 2024, Engineering

The work outlined here seeks to address the issue of detection and tracking of a moving object using a moving Event-Based Sensor (EBS) camera. Others have solved this issue by using power-hungry Convolutional Neural Networks (CNNs) which negate the low Size, Weight, And Power (SWAP) and high-speed benefits of an EBS camera. Throughout this paper, an attempt is made to solve the detection and tracking problem while keeping the low SWAP benefits of the EBS camera. This starts by looking at lightweight stationary EBS tracking algorithms and applying neuromorphic and hyperdimensional computing approaches to optimize the storage and runtime of the software. Ultimately, it was determined that the original approach was more time-efficient and therefore was used as a starting point for the Moving Sensor Moving Object (MSMO) detection and tracking algorithm. The MSMO algorithm uses the velocities of each event to create an average of the scene and filter out dissimilar events. This work shows the study performed on the velocity values of the events and explains why ultimately an average-based velocity filter is insufficient for lightweight MSMO detection and tracking of objects using an EBS camera.

Doctor of Philosophy, The Ohio State University, 2024, Food, Agricultural and Biological Engineering

The smoking process for a food product involves the deposition and absorption of smoke on the product surface, followed by a drying step to reduce the product moisture content to a defined level. The uniformity of air velocity and temperature within a smokehouse significantly influences final product quality, including color, texture, and flavor. Additionally, process efficiency and production capacity depend on uniform heat and mass transfer at the surface for all products in the smokehouse. While Computational Fluid Dynamics (CFD) has been used to study airflow patterns, air velocity and temperature distributions due to ventilation systems, research on applications to airflow distribution in a smokehouse have been limited. The overall objective of this research was to develop and validate CFD simulations of a smokehouse ventilation system to investigate the applications to airflow uniformity within a smokehouse. A CFD simulation of airflow distribution in a smokehouse without product was developed and used to investigate the influence of smokehouse ventilation configuration on uniformity of air velocity. The ventilation system configuration with outlet vents positioned near the inlet vents at both sides of the smokehouse ceiling exhibited the highest air velocity uniformity index of 0.64. An investigation of three different outlet vent dimensions indicated that outlet vent size did not influence the uniformity of air velocity distribution within the empty smokehouse. The influence of model products in the smokehouse was investigated using the CFD simulation. The average air velocity at 20 locations decreased from 3.9 ±1.4 m/s to 2.7 ±0.90 m/s when the ratio of model product to smokehouse volume was increase from 0 to 0.047. The influence of ventilation configuration was also evaluated by comparing outlet vents positioned near the inlet vents at both sides of the smokehouse ceiling to the outlet vent located in the ceiling at the middle of the smokehouse. The ave (open full item for complete abstract)

Masters of Science in Kinesiology and Health, Miami University, 2023, Kinesiology, Nutrition, and Health

No study has been published that determines whether torque production and neuromuscular fatigue is affected by skeletal muscle architecture and physical training methodologies during an acute bout of resistance exercise. PURPOSE: This study compared muscle architecture and torque characteristics during resistance exercise done to fatigue in highly trained endurance and sprint athletes. METHODS: 13 male collegiate athletes volunteered for this study. On Day 1, anthropometric, body composition, and muscle imaging measurements were made. Practice trials of the leg extension exercise were conducted on an isokinetic dynamometer. On Day 2, exercise trials were conducted at velocities of 100|50 and 50|50 degrees per second until fatigue. EMG and fNIRS devices were used to measure fatigue. RESULTS: Athlete type had a significant effect on minimum torque and percent drop in torque for the 100|50 trials. Fascicle length was negatively correlated with pennation angle and positively correlated with muscle thickness. CONCLUSION: Training methodologies have not significantly influenced muscle architecture of the subjects in this study. Sprint group showed a greater drop in torque during the 100|50 velocity fatiguing bout of resistance exercise than EDR. This may be evidence to support that endurance athletes are better able to resist large drops in torque when fatigued.

Master of Science (MS), Wright State University, 2023, Earth and Environmental Sciences

Estimating sediment thickness and bedrock surface geometry is critical for many hydrogeologic studies. The horizontal-to-vertical spectral ratio (HVSR), a passive seismic method is a unique, non-invasive technique for speedily estimating bedrock depth. To record ambient seismic noise, the H/V method employs a single broadband three-component seismometer. A field assessment was conducted on the Wright State University Campus in Dayton, Ohio, to determine the depth (z) and elevation of the bedrock. Data were collected at 60 different locations. A known value for the depth of bedrock on campus was determined using the log from a local water well available from the Ohio Department of Natural Resources. Using this depth and the observed fundamental resonant frequency (f0) the shear wave velocity (Vs) of the glacial drift above bedrock was calculated, which was then used to determine the depth of bedrock and its elevation in relation to the fundamental resonant frequency (f0). The HVSR results generally produced distinct, easily discernible resonance frequency peaks which together with the Vs constrained at the local borehole allowed the depth to bedrock and thereby bedrock elevation to be mapped across campus. The interpreted depth and elevation of the bedrock surface are comparable with previous surveys on campus.

Undergraduate Honors Program, Malone University, 2023, Honors Thesis

Pitchers with higher spin rates generally see higher swing and miss rates when pitching. The goal of this study was to find out how to improve spin rates without cheating (using foreign substances like pine tar). The hypothesis was that an increase in grip strength would show a positive correlation to spin rate. The study split 37 athletes into two groups. Both groups went through preliminary testing. The test group received extra grip strength exercises while the control group did the normal lifting routine for a three-month period. At the end of the study, post-testing data was collected for both groups. The data proved to be inconclusive, as there were no significant differences in grip strength between the test group and the control group.

Masters of Science in Kinesiology and Health, Miami University, 2023, Kinesiology, Nutrition, and Health

Riding an electric bike (EB) is a form of light to moderate-intensity aerobic physical activity (PA). Regular aerobic PA decreases central arterial stiffness and plasma endothelin-1 (ET-1), contributing to reduced cardiovascular disease risk. PURPOSE: To determine the effects of riding an EB for one week on central arterial stiffness and plasma ET-1. METHODS: Twelve healthy and recreationally active adults [49 ± 13 y; BMI = 26.3 ± 5.7 kg/m2] were monitored for one week without an EB (no EB) and one week with an EB. Participants were instructed to ride the EB a minimum of 4 d/wk for 30 min/d. An accelerometer tracked PA continuously for 14 days. Blood pressure, carotid-femoral pulse wave velocity (cf-PWV), and plasma ET-1 were measured at day 1 and day 14. One-way repeated measures ANOVA was performed to compare data between trials and Pearson correlations determined associations among study variables. RESULTS: Resting blood pressure and plasma ET-1 were unchanged, whereas cf-PWV decreased by 6.1% (p = 0.04) with EB use. No significant associations were discovered between PA, plasma ET-1, and cf-PWV. CONCLUSION: Our findings show that riding an EB for 1 week decreased central arterial stiffness in healthy adults.

Master of Science, The Ohio State University, 2023, Mechanical Engineering

Global vehicle emission regulations along with a growing consumer demand is a driving force in shifting the automotive industry towards a cleaner future. This shift requires significant automotive advancements in energy efficiency. Powertrain electrification and connected and autonomous vehicle (CAV) technology are key innovations that can reduce energy consumption and emissions. This thesis aims to improve the energy efficiency of a vehicle under varying conditions and determine the effect of charging on energy consumption. The vehicle model is established and utilized in the formulation of an optimal control problem in order to minimize energy consumption. The developed method to solve the optimization problem is applied in a large-scale study, culminating in an analysis of the effects of varying charging behavior on the energy consumption of the vehicle. The vehicle model is developed and validated over 25 real-world cycles resulting in an average fuel consumption, battery energy consumption, and total energy consumption errors of 2.2%, 2.9%, and 2.8%, respectively. The velocity dynamics and powertrain of the modeled vehicle are co-optimized to improve a weighted cost between energy consumption and travel time. The optimization results in an average decrease of 10% in fuel consumption, 8% in battery energy consumption, and 19% in total energy consumption. Lastly, the large-scale study reveals a correlation between charging behavior and both the effect of charging event placement and the presence of look-ahead information on energy efficiency. The resulting trends in charging behavior give context for energy efficient trip planning.