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Guo, QiA Framework for Optimal Decision Making of a Photovoltaic Recycling Infrastructure Planning
Doctor of Philosophy (Ph.D.), University of Dayton, 2017, Mechanical Engineering
Solar energy, as an emerging renewable clean energy, has been rapidly growing for 15 years all over the world and is expected to grow 15% annually until 2020. In 2015, at least 40 GW of Photovoltaic (PV) systems were installed, achieving 178GW current solar power installation worldwide. In the next five years, 540 GW cumulative capacities are expected to be installed worldwide and US contributed 6.5 GW PV installations in 2015. US electricity demand is expected to be dominated by solar power by 2050 or even earlier. The widespread deployment of PV will not only contribute to a reduction in greenhouse gas emission, but can also mitigate the worldwide fossil fuel depletion. As the number of PV systems increases, the mass of PV waste will increase as well, adding a new source to the existing waste stream. The amount of End-of-Life (EoL) PV will approach 13.4 million ton worldwide, including approximately 5.5 million ton located in the US by 2025. PV contains high value, toxic, and energy-intensive materials. In addition, the market price of some materials utilized in the thin-film and crystalline PV technologies has drastically increased in the recent years. There is a strong need of coordinating the information to optimize the reverse logistics planning in a photovoltaic (PV) recycling network in the U.S. Two major tasks are included: 1) locating PV Recycling Centers (PVRC); 2) allocating Transportation Companies (TC) shipping PV installation sites (PVIS) to PVRC. One contribution of this dissertation is to decide the optimal number, as well as the location of PVRC by minimizing the overall cost. Another contribution is to determine the optimal distribution scheme to minimize the transportation cost among TC, PVIS, and PVRC. In order to accomplish the two tasks, a mathematical modeling framework was developed to facilitate PV recycling in an economically and environmentally feasible manner. The framework included two mathematical models: 1) Multi-Facility Optimization Model; 2) Optimal Distribution Model. The multi-facility optimization model included the transportation module, the economic module, and the environmental module. The model identifies the geographical location of the prospective PVRCs by minimizing the total costs in different scenarios. While in the Optimal Distribution Model, a static and a dynamic optimization algorithm was applied for conducting the optimal solution accurately and efficiently. To show the efficacy of the proposed framework, case studies for recycling EoL PV in California were performed. Historical PV installation data in the region was utilized to gather information about the amount of the prospective end-of-life (EoL) PV waste generation in CA. In order to integrate the temporal and the spatial dispersion of PVISs in CA, a three-phase recycling plan was proposed. For well displaying the geographical results, Geographic Information System (GIS) was utilized to visualize the installation data, optimized location of the PVRCs, and the optimal distribution scheme. The proposed generic framework provided a great insight for decision makers about the trade-offs among various scenarios by considering cost, environmental impact, and investment risk on PV recycling planning.

Committee:

Jun-Ki Choi (Advisor); Chuck Ebeling (Committee Member); Ron Deep (Committee Member); Shuang-ye Wu (Committee Member)

Subjects:

Energy; Mechanical Engineering

Keywords:

PV recycling, Optimization, End-of-Life recycling framework

Hutten, Victoria ElizabethProcess Modeling of Thermoplastics and Thermosetting Polymer Matrix Composites (PMCs) Manufactured Using Fused Deposition Modeling (FDM)
Master of Science (M.S.), University of Dayton, 2017, Mechanical Engineering
In this work, a model framework for the simulation of Fused Deposition Modeling (FDM) of thermoplastic and thermosetting polymers and Polymer Matrix Composites (PMCs) was developed. A Python script was constructed to automatically generate a 3D finite element heat transfer and stress model of individual roads within a 3D printed part. The script creates the road activation sequence based on the print path specified in the part G-code and associated boundary conditions which are continuously updated throughout the analysis with minimal input from the user. Thermosetting polymers and polymer matrix composites (PMCs) are modeled by implementing a material sub-model from Convergent Manufacturing Technologies called COMPRO that captures the curing kinetics of the material during the printing and post-cure cycle. The modeling approach is formulated for both material systems through tailorable conditions such as build plate temperature, ambient conditions, print temperature, etc. To the author’s knowledge, no 3D finite element model of the FDM process exists for the thermal history and residual stress prediction of thermosetting polymers and PMCs. Although the objective of this work is to create a model for the prediction of thermosetting polymers and PMCs, the characterization and subsequent printing of these materials is still in the development stages. Therefore, in order to validate that the proposed model is capturing the correct physics for the FDM process, model predictions for Acrylonitrile Butadiene Styrene (ABS) coupons were compared with experimentally printed specimens. A series of sensitivity studies were then performed for this model to investigate significant effects as well as trends in the predictions from assumptions in the boundary conditions. The model is then extended to thermosetting PMCs to demonstrate the linkage between COMPRO and the modeling framework.

Committee:

Robert Brockman, PhD (Committee Chair); Brent Volk, PhD (Committee Member); Thomas Whitney, PhD (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

finite element analysis; process modeling; fused deposition modeling; polymer matrix composites; thermosetting polymers

Smith, GregoryAn Analysis of Critically Enabling Technologies for Force and Power Limiting of Industrial Robotics
Master of Science (M.S.), University of Dayton, 2017, Electrical Engineering
The power and force limited (PFL) industrial robot market is one that is much underdeveloped and market demand is increasing every year. A literature review of critically enabling technologies for PFL robotics is conducted to evaluate the successes and limitations of developed and emerging PFL technologies. From this analysis a one link robot testbed is developed to test and gain a deep understanding of inherent torque sensing properties. Two custom sensing configurations and two custom torque plates are also designed to evaluate key torque sensing properties. Finally, an evaluation on these results lead to conclusions of the inherent effectiveness of the selected PFL enabling technologies.

Committee:

Raul Ordonez, Ph.D (Committee Chair); Russell Hardie, Ph.D (Committee Member); Chetan Kapoor, Ph.D (Committee Chair)

Subjects:

Robotics

Keywords:

Torque Sensor; Harmonic Drive; Capacitive Sensor; Optical Encoder; Power and Force Limited

Flynn, Michaline L.Post-Secondary Transitions for Students with High-Incidence Disabilities
Specialist in Education (Ed.S.), University of Dayton, 2017, School Psychology
The transition from high school to post-secondary life is especially difficult for students with high-incidence disabilities.The purpose of the present study was to examine the educational experiences of students with high-incidence disabilities, such as ASD, specific learning disability, and ADHD, who received post-secondary transitional services. Participants included (n = 25) seniors in high school with current IEPs, who completed questionnaires regarding their experience with post-secondary transitional services and were interviewed after graduation to share their perceptions of the process and services they received to prepare them for post-secondary life Results suggest that participants perceive themselves as prepared for their post-secondary goals both before graduation and during the fall after graduation; however, they do not attribute their readiness to the services received in school. Implications for practice and future research are discussed.

Committee:

Susan Davies, Dr. (Committee Chair); Elana Bernstein, Dr. (Committee Member); Nasser Razek, Dr. (Committee Member)

Subjects:

Psychology

Keywords:

Post-Secondary Transitions; Special Education; High-Incidence Disabilities; School Psychology; High School

Li, KaiyuSupramolecular Ruthenium(II) and Osmium(II) Complexes: Synthesis, Characterization, DNA Binding and DNA Photocleavage
Master of Science (M.S.), University of Dayton, 2017, Chemistry
Two new bridging ligands have been synthesized by combining substituted benzaldehydes with phenanthrolinopyrrole (php), resulting in new polyazine bridging ligands. The ligands have been characterized by 1H NMR, mass spectroscopy, and elemental analysis. These new ligands display π-π* transitions above 500 nm with modest molar absorptivities. Upon excitation at the ligand-centered charge-transfer transition, weak emission with a maximum wavelength of 612 nm is observed. When coordinated to two ruthenium (II) bis-(2,2’-bipyridine) groups, the new bimetallic complexes generated give an overall 4+ charge. The electronic transitions of the bimetallic ruthenium (II) complexes display traditional π-π* transitions at 287 nm and metal-to-ligand charge-transfer transitions at 452 nm with molar absorptivities greater than 30000 M-1 cm-1. Oxidation of the ruthenium (II) metal centers to ruthenium (III) occurs at potentials above 1.4 V versus the Ag/AgCl reference electrode. Spectroscopic and electrochemical measurements indicate that the ruthenium (II) moieties behave independently. Both complexes are water-soluble and show the ability to photo-nick plasmid DNA when irradiated with low-energy light above 550 nm. In addition, one of the complexes, [Ru(bpy)2php]2Van4+, shows the ability to linearize plasmid DNA and gives evidence, by gel electrophoresis, of photoinduced binding to plasmid DNA. Coordination of two Osmium(II) bis-(bipyridine) complexes to the peripheral phenanthroline of (4-hydroxy-3- methoxyphenyl)diphenanthropyrromethane ligand yields the bimetallic Os(II) complex. The spectroscopic properties are similar to those of [Os(bpy)3]2+ with ligand-centered π-π* transitions in the UV region of the spectrum and three metal-to-ligand charge-transfer (1MLCT) transitions in the visible region. A broad 3MLCT is observed stretching from 550 to 700 nm with modest intensity. Binding studies with calf thymus DNA (ctDNA) show binding constants as high as 105 M–1 indicating a strong interaction of the complex with DNA. When aqueous solutions of the complex and plasmid DNA are irradiated with low-energy light for brief periods of time complete photo- cleavage of the DNA is observed. Studies indicate that the mechanism of this photoreaction requires molecular oxygen and results from both the formation of 1O2 and oxygen radicals offering multiple modes for DNA destruction.

Committee:

Shawn Swavey (Committee Chair); Kevin Church (Committee Member); Mark Masthay (Committee Member)

Subjects:

Chemistry

Keywords:

Photosensitizer; Ruthenium; Osmium; Bimetallic complexes; DNA Photocleavage

Razzaghi, Hesham M.Spatial Analysis of Alcohol-related Injury and Fatal Traffic Crashes in Ohio
Master of Science (M.S.), University of Dayton, 2017, Civil Engineering
Traffic crashes are considered alcohol-related if blood alcohol concentration (BAC) of a driver or non-motorist is 0.08 grams per deciliter (g/dl) or above. This thesis analyzed various socioeconomic factors that may influence alcohol-related fatal and injury crashes in Ohio at the county level in order to determine counties that may need heightened attention in terms of enforcement and education campaigns. This study used three years of Ohio traffic crash data at the county level from 2012 to 2014 obtained from the Ohio Department of Public Safety (ODPS). The objective of this study was to explore the use of an Ordinary Least Squares (OLS) regression method in identifying factors affecting alcohol-related fatal and injury crashes in Ohio at the county level. This study was done by using Geographic Information System (GIS) in order to utilize its spatial capabilities. The model of alcohol-related fatal and injury traffic crashes was initially built with 15 independent variables that may affect alcohol-related traffic crashes such as population density and household income. The variables were divided into four groups namely crash response variables, road network variables, traffic variables, and socio-demographic variables. The Moran’s I index for residuals was almost equal to zero demonstrating that there was little evidence of any autocorrelation between each other, then OLS model was deemed adequate in modeling the data used in the this study. After removing highly correlated variables, only four variables were found to be significantly affect the rates of alcohol-related traffic crashes at the county level at a 90% confidence level. The variables found significant include percent of males in the population in the county, percent of trucks in the vehicles registered in the county, percent of licensed drivers per population in the county, and elevation range in the county.

Committee:

Deogratias Eustace (Advisor)

Subjects:

Civil Engineering

Keywords:

Spatial Analysis, Alcohol-related Traffic Crashes and Ordinary Least Squares

Amonson, Michael D.Multiple Charge Carrier Species and Their Effects in Photorefractive Two-Beam Coupling in Potassium Niobate
Master of Science (M.S.), University of Dayton, 2017, Electro-Optics
This thesis reports on an experiment to measure charge carrier contributions from different Fe species and their effects on beam coupling efficiency using self-pumped counter-propagating two-beam coupling in iron-doped potassium niobate KNbO3:Fe. We used multiple continuous wave lasers operating across the visual spectrum to explore charge carrier creation from various transitions. Photorefractive grating formation data was acquired and analyzed using a new theoretical model which incorporates multiple charge carrier species. Initial analysis provides supporting evidence of a multiple charge carrier model and presents new insights about the effects of various charge carriers on the photorefractive periodic space-charge fields.

Committee:

Dean Evans (Advisor)

Subjects:

Electromagnetism; Materials Science; Optics; Physics

Keywords:

Potassium Niobate; Iron Doped Potassium Niobate; Photorefractive; Multiple Charge Carriers; Two-Beam Coupling

Long, Brandon ScottEffect of Rayleigh-Taylor Instability on Fuel Consumption Rate: A Numerical Investigation
Master of Science (M.S.), University of Dayton, 2017, Aerospace Engineering
An extensive numerical investigation is conducted in order to assess the effect of Rayleigh-Taylor instability on fuel consumption rate (or flame speed). Two geometries are used for this investigation, viz., a high pressure high-g (HPHG) cavity stabilized combustor and a curved duct with a backward facing step. The former geometry is a more practical combustion system that contains liquid fuel injectors with operating conditions that mimic gas turbine cycles, whereas the latter is a canonical combustor used to study turbulent premixed flames. Reynolds averaged Navier-Stokes (RANS) and large eddy simulations (LES) are used. RANS is used for the practical combustor, and both RANS and LES are used for the canonical combustor. The combustion models used are the flamelet generated manifold (FGM) and the two-step species transport for the practical and canonical combustor, respectively. The HPHG combustor is designed to induce bulk rotational flow in the cavity, inducing centrifugal acceleration. The centrifugal force acts from the high-density reactants towards the low-density products creating a Rayleigh-Taylor instability (RTI). Rayleigh-Taylor instabilities are expected to increase the turbulent flame speed and reduce the size of the combustor by increasing the flame wrinkling and/or corrugation. Simulations at two different levels of centrifugal acceleration, and, consequently, dissimilar Rayleigh-Taylor instability were performed. It was found that the nominal g-loads are overestimating the local g-loads from the simulation because thermal expansion is not taken into account. From these simulations it was not possible to discern the effect of RTI on fuel consumption rate due to the complex physical-chemical process inherent to this combustor such as fuel vaporization, molecular mixing, spray-turbulence interaction, turbulence-chemistry interaction, and partial premixing. Therefore, gaseous premixed turbulent flames were simulated in a curved duct with a backward facing step. Two radius of curvature were used, viz., an infinite (straight duct) and a finite radius of curvature (curved duct). These combustors were operated at low and high Reynolds number (3,200 and 32,000). The computational results are compared with broadband chemiluminescence and shadowgraph images reported in the literature for similar conditions and geometries. Both RANS and LES results are in general agreement with measurements. Both experiments and simulations show that increasing the Reynolds number in both straight and curved canonical combustor the flame cannot withstand the Karlovitz number effects and the flame is positioned behind the backward-facing step. In addition, the LES results indicate that at high Reynolds number the flame blows out for the straight channel while it remains stabilized for the curved channel. This result is in agreement with the blowout data reported in the literature. On the other hand, RANS over predict the flame stabilization for the straight channel. Consequently, RANS should not be used in research involving RTI-induced blowout. In conclusion, RTI interacts with a turbulent premixed flame and its overall effect is to extend the conditions under which turbulent premixed flames can be stabilized. This improved flame stabilization is a direct manifestation that the fuel consumption rate (or flame speed) has been enhanced in order for the flame to withstand higher Karlovitz number effects induced by high Reynolds number. However, the mechanism through which RTI works on the turbulent premixed flame is not clear. A new hypothesis is proposed. The increase in RTI should increase the turbulent length scale as well as increase the Karlovitz number. The corrugated flame would withstand the higher Karlovitz number because RTI temporarily and periodically reverses the turbulent energy cascade by minimizing the potential energy of the stratified flow.

Committee:

Scott Stouffer, Ph.D. (Committee Chair); Alejandro Briones, Ph.D. (Committee Member); Brent Rankin, Ph.D. (Committee Member); Jamie Ervin, Ph.D. (Committee Member)

Subjects:

Aerospace Engineering

Keywords:

Rayleigh-Taylor Instabilities; Fuel Consumption Rate; High Swirl Combustion; High-G Combustion; Backward Facing Step Combustion

Sargent, Garrett CraigSingle-Image Super-Resolution via Regularized Extreme Learning Regression for Imagery from Microgrid Polarimeters
Master of Science (M.S.), University of Dayton, 2017, Electrical and Computer Engineering

Division of focal plane imaging polarimeters have the distinct advantage of being capable of obtaining temporally synchronized intensity measurements across a scene; however, they sacrifice spatial resolution in doing so due to their spatially modulated arrangement of the pixel-to-pixel polarizers and often result in aliased imagery. This shortcoming is often overcome through advanced demosaicing strategies that minimize the effects of false polarization while preserving as much high frequency content as possible. While these techniques can yield acceptable imagery, they tend to be computationally complex and the spatial resolution is often reduced below the native capabilities of the focal plane array. This thesis proposes a super-resolution method based upon a previously trained regularized extreme learning regression (RELR) that aims to recover missing high-frequency content beyond the spatial resolution of the sensor and correct low-frequency content, while maintaining good contrast between polarized and unpolarized artifacts presented in this thesis. For each of the four channels of the image, the modified RELR predicts the missing high-frequency and lowfrequency components that result from upsampling. These missing high-frequency components are then refined with a high pass filter and added back to the upsampled image. This provides a fast and computationally simple way of recovering missing high frequency components that are lost with current state-of-the-art demosaicing algorithms. The modified RELR provides better results than other visible band single-image super-resolution techniques and is much faster, thus making it applicable to real-time applications. The obtained results demonstrate the effectiveness of the modified RELR for a truth scenario (no aliasing resulting from undersampling) and a derived microgrid scenario (aliasing resulting from undersampling). The truth scenario shows that the modified RELR performs exceptionally better than other algorithms, however, the derived microgrid scenario demonstrates the problems that result from aliasing for single-image super-resolution algorithms. In general, for the degree of linear polarization (DoLP) image product, aliasing greatly distorts objects within a scene and none of the super-resolution algorithms could do anything to correct for it. The modified RELR showed superior performance against other super-resolution algorithms investigated at maintaining contrast between the polarized and unpolarized artifacts, which is of great importance. Future work is dedicated to coming up with fast ways to handle aliasing that is present in true microgrid imagery.

Committee:

Vijayan Asari, Ph.D. (Advisor); Bradley Ratliff, Ph.D. (Committee Member); Eric Balster, Ph.D. (Committee Member); Theus Aspiras, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Engineering

Keywords:

single image super resolution; microgrid polarimeter; machine learning; extreme learning machine

Slye, Matthew ScottHobo Noah
Master of Arts (M.A.), University of Dayton, 2017, English
In “Hobo Noah,” Claudia wakes in the middle of the night in her new apartment to find her son Noah sleeping under the dining room table. This discovery jumpstarts an examination of Claudia’s split with Terri, her long-time partner, and Claudia’s move out of the house she shared with Terri and their twin boys. As Claudia’s drinking escalates, her already fracturing family learns that they can no longer rely on her, especially when Noah is found sleeping in a neighbor’s yard at night while he is supposed to be in Claudia’s care. In “The Retarded Angel,” Sam Gerich writes the story of the boy with the shell, a human-like character with a large shell on his back, and his quest to find his family and a mysterious flashlight that was described to him by a priest. As the boy with the shell travels from town to town looking for his family and this flashlight, he meets a number of mysterious figures. An old man and his friends viciously attack the boy, attempting to rob him. A man with claws and a doctor help the boy to recover. An old woman recruits the boy into a clandestine operation that smuggles babies from one town to another. The boy with the shell eventually meets a lighthouse operator and attempts to steal the lighthouse operator’s fire starter. When the boy’s plan is foiled, he throws himself from the top of the lighthouse. He survives the fall, but his shell breaks, revealing wings underneath.

Committee:

Joseph Pici (Advisor)

Subjects:

American Literature; Gender Studies

Keywords:

twins in fiction; short story cycle; head lice; metafiction

Hussain, Mallik Mohd RaihanNonlinear Electromagnetic Radiation from Metal-Insulator-Metal Tunnel Junctions
Master of Science (M.S.), University of Dayton, 2017, Electro-Optics
Our goal was to experimentally detect nonlinear electromagnetic (EM) radiation (in the far field) from a metal-insulator-metal (MIM) tunnel junction where the insulator thickness lies in the nanometer to subnanometer range and the metals in the junction are coupled to the electromagnetic field of incident photons. The radiation from an MIM junction originated from the photon-induced tunneling current passing through it. The phenomenon is elegantly described by photon-assisted-tunneling (PAT) theory that introduces transfer Hamiltonians in the uncoupled (when two metals are at infinite distance from each other) system Hamiltonian. This theory predicts the contribution of additional conductivity terms in the MIM interface (due to tunneling inside the junction) and ushered the development of quantum conductivity theory (QCT), as a consequence. In this thesis, we reviewed QCT from the perspective of many-body formulation and designed careful experiments to detect the nonlinear electromagnetic radiation from MIM junctions that can be attributed to photon-assisted tunneling of electrons. In our experiment, first, an insulator layer was put on the metal surface using atomic layer deposition (ALD) technique. The number of layers were varied to produce MI samples with different insulator thickness in the subnanometer range. Then, we set the background signal strength by measuring the second harmonic (SH) and third harmonic (TH) signal due to the bulk material and the surface of metal-insulator (MI) interface. Next, we spin-coated the MI sample with Au nanospheres (diameter ~ 10 nm) to construct MIM interfaces and measured SH and TH signals from them again. Without any bias voltage across the MIM, QCT predicts an increase in TH signal only. Experimentally, we observed an increase in TH signal strength. The increase was modest which is partially attributed to the fact that we could not reliably produce MIM samples with subnanometer insulator thickness and uniform coverage. We intend to improve the surface coverage and uniformity of the insulator layer, in future, and measure SH and TH from the improved samples. Detection of such radiation would support QCT and validate the extension of transfer Hamiltonian approach from the realm of superconducting tunnel junctions to normal MIM tunnel junctions.

Committee:

Joseph Haus, Ph.D. (Committee Chair); Andrew Sarangan, Ph.D. (Committee Member); Imad Agha, Ph.D. (Committee Member)

Subjects:

Electromagnetics; Nanoscience; Nanotechnology; Optics; Quantum Physics

Keywords:

tunnel junction; metal-insulator-metal; MIM; nonlinear radiation from MIM; transfer Hamiltonian; photon-assisted-tunneling; PAT; quantum conductivity coefficient; QCT; Au-Al2O3-Au; atomic layer deposition on metal; ALD on metal; metal-insulator; MI

Kuebel, Laura A.Effectiveness of a Social Skills Curriculum on Preschool Prosocial Behavior and Emotion Recognition
Specialist in Education (Ed.S.), University of Dayton, 2017, School Psychology
Preschool children in public school programs are expelled at three times the rate of their K-12 peers. Research demonstrates a decreased emphasis on social-emotional skill development in preschool, despite high incidences of problem behaviors. The present study investigated the effectiveness of a commercially available social skills curriculum on preschoolers’ social-emotional development, specifically their pro-social behaviors and emotion recognition. Results showed that students who participated in the social skills curriculum increased prosocial skills and ability to visually recognize emotions in others. While statistical measures indicate that the intervention did not have a statistically significant impact on student emotion recognition and prosocial behavior, anecdotal reports from participating teachers indicated that the intervention was highly beneficial to participating students. Further, the curriculum had a high level of treatment acceptability by participants’ teachers. Implications regarding social emotional curriculum and preschool students’ prosocial skill and emotion recognition development are provided.

Committee:

Elana Bernstein (Committee Chair); Susan Davies (Committee Member); Joni Baldwin (Committee Member)

Subjects:

Curricula; Preschool Education

Keywords:

preschool; social emotional; emotion recognition; prosocial behavior; curriculum

Wagner, ChristopherRegression Model to Project and Mitigate Vehicular Emissions in Cochabamba, Bolivia
Master of Science (M.S.), University of Dayton, 2017, Renewable and Clean Energy
The purpose of this study is to generate a regression model tying the vehicular emissions in Cochabamba, Bolivia to input factors including the current state of the public fleet, city population, weather, and GDP. The finished model and the process to generate it can act as a tool to project future emissions in the city, accounting for the aforementioned input factors. It can also be used to estimate the drop in city pollution levels in a scenario where the public transportation fleet is partially replaced by non-emitting, electric vehicles. The main pollutant focused on in this study is particulate matter (PM10), but data also exists for ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2). The model generation process explained in the study could be applied to these pollutants as well. The regression model is generated using the open source software, R. Its final form utilizes a random forest regression model, but neural net, gradient boosting, and support vector machine models were also explored.

Committee:

Robert Brecha, Ph.D. (Committee Chair); Andrew Chiasson, Ph.D. (Committee Member); Malcolm Daniels, Ph.D. (Committee Member)

Subjects:

Engineering; Environmental Engineering; Mechanical Engineering

Keywords:

Random Forest Model; Vehicular Fleet; Cochabamba, Bolivia; Vehicle Emissions; Predictive Ensemble Model

Yang, ZhijunIncoherent Imaging in the Presence of Atmospheric Turbulence and Refractivity
Doctor of Philosophy (Ph.D.), University of Dayton, 2017, Electro-Optics
Atmospheric turbulence, associated with its refractive-index inhomogeneities (refractivity), may severely affect long range incoherent images formation. Example of this impact includes image blurring, motion, warping and anisotropic geometrical distortions. Currently, the effects of turbulence and refractivity on image formation are considered as being mutually independent and analysed separately using the Fresnel diffraction (wave-optics) and geometrical optics (ray tracing) approaches, respectively. Such independent treatment of turbulence and refractivity effects have certain limitations. Atmospheric refractivity may result in significant deviations of optical wave propagation direction. This effect is commonly referred as the ray bending which, in turn, may lead to a change in turbulence characteristics such as the refractive index structure parameter Cn2 that is commonly considered as a function of altitude h above the ground. Correspondingly, optical wave refraction, especially in extended-range imaging scenarios, could affect the turbulence-induced optical aberrations. In this work, we analyze the incoherent image formation in atmosphere in the presence of both atmospheric turbulence and refractivity using numerical simulations based on the brightness function (BF) technique. Using the BF technique, the incoherent imaging system modulation transfer function (MTF) estimation is performed via direct numerical analysis of visibility of sine-test patterns of different spatial frequencies. The test patterns are assumed to be imaged through a volume medium with turbulence and refractivity-induced refractive index inhomogeneities. The major effects observed in numerical simulations, include the spatial frequency shift between frequency of a sine-test object and its image, and spatial non-uniformity of the sine-pattern image distortion which is referred as the refractivity-induced image anisoplanatism. Both effects depend on the location and strength of the localized refractive index structure with respect to the imaging (wave propagation) geometry. The MTFs corresponding to distributed (volume) turbulence with and without atmospheric refractivity are also compared. Next, the joint impact of atmospheric turbulence and inverse temperature layer (ITL) on optical mirage formation is analyzed. The dependency of both desert- (superior) and ocean-type (inferior) mirage image formation on ITL characteristics (temperature inversion and location of the ITL) have been studied. The impact of atmospheric turbulence strength on mirage image qualities is also analyzed. Finally, a numerical analysis is conducted to study the impact of localized refractive index inomogeneites on image quality. It is shown that image quality strongly depends on atmospheric turbulence strength and locations along the optical path. To characterize this impact, two metrics are proposed and developed to measure the image quality as a function of turbulence strength and location. The impact of inverse temperature layer on the developed image quality metrics are also studied.

Committee:

Mikhail Vorontsov (Advisor); Partha Banerjee (Committee Member); Edward Watson (Committee Member); Steven Fiorino (Committee Member)

Subjects:

Atmospheric Sciences; Engineering; Optics

Keywords:

incoherent imaging; atmospheric turbulence; refractivity; modulation transfer function; optical mirage

McDaniel, Sean A.Mid-IR Ultrafast Laser Inscribed Waveguides and Devices
Doctor of Philosophy (Ph.D.), University of Dayton, 2017, Electro-Optics
Ultrafast laser inscription (ULI) is a highly versatile technique for creating index modifications in glasses and crystalline materials. The process of ULI relies on ultrashort laser pulses focused inside of a material. The high intensity of the pulsed beam induces nonlinear absorption processes, which transfers the pulse energy to the material lattice. With careful experimental control of the laser parameters, a permanent change in the refractive can be obtained in the bulk material. The permanent refractive index change obtained by ULI can be used to create waveguides in active laser materials, such as Cr:ZnSe, Fe:ZnSe and Ho:YAG. Transition metal and rare-earth laser sources have been shown to operate over the 2 - 5 micron range. ULI can be used in conjunction with these materials to produce high power, guided-wave structures with reduced size, weight and power (SWaP) requirements. Power levels for Cr:ZnSe and Fe:ZnSe have been scaled to > 5 W and > 1 W respectively in ULI waveguide devices. Additionally, the first Ho:YAG ULI laser has been investigated, exhibiting output powers of ~ 2 W. In addition to these advances, the theoretical limit for transition metal waveguide lasers was investigated. Transition metal lasers are highly sensitive to the operating temperature of the laser device. If the temperature increase induced in the sample is too high, phonon assisted transitions become dominant, thus decreasing the performance of the laser. Laser rate-equations and a thermal model for ULI waveguides were developed to establish a theoretical limit to ULI waveguide operation. Finally, several advancements were made with respect to creating ULI waveguides. An algorithm was developed for creating arbitrary ULI structures from computer generated models. The ability to create arbitrarily generated structures provides the ability to create complex structures using ULI, such as splitters, couplers, and photonic lanterns. Furthermore, a new helical inscription technique was devised for creating smooth index profiles and for creating Bragg structuring.

Committee:

Gary Cook, Ph.D. (Committee Chair)

Subjects:

Engineering; Optics

Keywords:

Waveguide; Mid-IR Lasers

Miser, Rachael SpikerA Phenomenological Study of Secondary Teachers' Experiences with Assessing Higher Order Thinking Skills
Doctor of Philosophy (Ph.D.), University of Dayton, 2017, Educational Leadership
The study explored the experiences of seven effective high school teachers in assessing higher order thinking skills. For students to graduate an Ohio public school, they are to have the resources and skills to be college and career ready and according to the Ohio Learning Standards and developing higher order thinking is part of this mandate. Because of these demands, increased focus and attention is being directed to the development of knowledge beyond basic recall and rote memorization and towards deeper understanding, critical thinking, and problem solving. The methods used for this study were based on a qualitative phenomenological design that used a social constructivist framework and an ontological philosophical basis. Seven teachers from an Ohio secondary public-school district were the participants. Empirical data were collected through in-depth interviews and analysis of the data was through horizonalizing and finding themes, developing textural descriptions, and deriving meanings and essences. Twelve themes were constructed--internal classroom themes of defining higher order thinking, questioning, collaborative groups, problem and project based learning, demonstration of skills, instilling confidence, time; and external themes of administrators, professional development, teacher training, Common Core or Ohio Learning Standards, and collaboration with other teachers.

Committee:

Carolyn Ridenour (Committee Chair)

Subjects:

Education; Educational Leadership

Keywords:

phenomenology; assessing; higher order thinking skills; experiences of secondary teachers

Patterson, Erin LeighCompression of Medical Images Using Local Neighbor Difference
Master of Science (M.S.), University of Dayton, 2017, Electrical Engineering
Medical images are an essential part to any health professional’s career when helping patients and diagnosing health concerns. Due to the need for large storage capacity and fast transferring speed, research in image compression has grown. Image compression uses the property of redundant information in the image to reduce the amount of data in the image to solve both problems of storage and transmission. For medical images, lossless compression algorithms are of interest to make sure that the reconstructed image provides the same details as the original image. This thesis presents a proposed algorithm called the Local Neighbor Difference (LND) which is a preprocessing technique to allow the redundancy in the medical image to be reduced before being sent into a commercial-off-the-shelf compressor (COTS), XZ. LND, when used in conjunction with XZ losslessly, compresses images, on average, by 6% more than XZ alone. The LND process, along with some future work, is proposed in this paper and results in a viable option for a pre-process to a compressor.

Committee:

Eric Balster, Dr. (Advisor)

Subjects:

Electrical Engineering

Keywords:

medical images; lossless; image compression; XZ;

Elmushyakhi, AbrahamIn-Plane Fatigue Characterization of Core Joints in Sandwich Composite Structures
Doctor of Philosophy (Ph.D.), University of Dayton, 2017, Materials Engineering
In practice, adjacent preform sandwich cores are joined with a simple butt joint without special precautions. When molded, this gap is filled with resin and creates a resin rich area. Stress risers will be amplified under cyclic load, and consequently, the serviceability of the structure will be affected. Designers and researchers are aware of this problem; however, quantifying this effect and its intensity and consequence on the service life of the structures has not yet been developed. Despite pervious findings, limited experimental data backed by a comprehensive root cause failure analysis is available for sandwich under axial static, fatigue and post-fatigue. If such a comprehensive experimental characterization is conducted, specifically understanding the nature of the damage, intensity, and residual strength, then a valid multi-scale damage model could be generated to predict the material state and fatigue life of similar composite structures with/without core joints under in-plane static and fatigue load. This research study characterized the effect of scarf and butt core joints in foam core sandwich structures under in-plane static and fatigue loads (R=0.1 and R= -1). Post-Fatigue tensile tests were also performed to predict the residual strength of such structures. Nondestructive Evaluation Techniques were used to locate the stress concentrations and damage creation. A logical blend of experimental and analytical prediction of the service life of composite sandwich structures is carried out. The testing protocol and the S-N curves provided in this work could be reproducible and extrapolated to any kind of core material. This research study will benefit composite engineers and joint designers in both academia and industry to better apprehend the influence of core joints and its consequence on the functionality of sandwich structures.

Committee:

Elias Toubia (Advisor); Paul Murray (Committee Member); Thomas Whitney (Committee Member); Youssef Raffoul (Committee Member)

Subjects:

Aerospace Engineering; Aerospace Materials; Civil Engineering; Composition; Design; Engineering; Materials Science; Mechanical Engineering; Polymers

Keywords:

Sandwich Composite Structures; Design; Fatigue; Damage; Joints; Lightweight Materials; E-glass-vinyl ester; GFRP Laminate; Modeling; Prediction; Nondestructive Testing

Alrobaian, Abdulrahman AbdullahMulti-Spectral Remote Thermal Imaging for Surface Emissivity and Estimation of Roof R-Values Using Physics-Based and Data Mining Models
Doctor of Philosophy (Ph.D.), University of Dayton, 2017, Mechanical Engineering
Remote thermal imaging of buildings is notable for providing interesting but generally qualitative images of buildings. A recent study showed that if accurate measurements of exterior surface temperatures could be obtained from single-point-in-time-imaging, then it would be possible to infer envelope R-values and thermal capacitances with reasonable accuracy. This research seeks to answer the question, “How can we make possible reasonably accurate measurements of the external temperatures from at-scale remote imaging?” Without knowledge of the emissivity of the exterior surfaces, accurate thermal assessment is seemingly impossible. Here, we exploit the unique spectral characteristics of the most common exterior building surfaces using multi-spectral imaging. Four to five images of exterior surfaces in the 1-5-micron range, where the spectral emissivity of different building materials changes most, is posed. The pattern of the emission can be correlated to various envelope component surface spectral emissivities. A neural network pattern matching algorithm is used to `find’ the surface type. Then, with known emissivity, the surface temperature can be inferred from the magnitude of the emission. Theoretical results indicate that temperature error in measuring the surface temperature in using this approach can be less than ±1oC. This error is sufficient for identifying envelope R-values based upon the research posed by Salahaldin and Hallinan [1]. Most exciting is the prospect of this technique for effectively measuring building R-values at scale via fly-over or drive by imaging. Conventional residential building energy auditing needed to identify opportunities for energy savings is expensive and time consuming. On-site energy audits require quantification of envelope R-values, air and duct leakage, and heating and cooling system efficiencies. There is a need to advance lower cost automated approaches, which could include aerial and drive-by thermal imaging at-scale in an effort to measure the building R-value. However, single-point in time thermal images are generally qualitative, subject to errors stemming from building dynamics, background radiation, wind speed variation, night sky thermal radiation, and error in extracting temperature estimates from thermal images from surfaces with generally unknown emissivity. This work proposes two alternative approaches for estimating roof R-values from thermal imaging, one a physics based approach and the other a data-mining based approach. Both approaches employ aerial visual imagery to estimate the roof emissivity based on the color and type of roofing material, from which the temperature of the envelope can be estimated. The physics-based approach employs a dynamic energy model of the envelope with unknown R-value and thermal capacitance. These are tuned in order to predict the measured surface temperature at the time of the imaging, given the transient weather conditions prior to the imaging. The data-mining approach integrates the inferred temperature measurement, historical utility data, and easily accessible or potentially easily accessible housing data. A data mining regression model, trained from this data using residences with known R-values, is used to predict the roof R-value in the unknown houses. The data mining approach was shown to be a far superior approach, demonstrating an ability to estimate attic/roof R-value with an r-squared value of greater than 0.88 using as few as nine training houses. The implication of this research is significant, offering the possibility of auditing residences remotely at-scale via aerial and drive-by thermal imaging coupled with utility analysis.

Committee:

Kevin Hallinan (Advisor); Andrew Chiasson (Committee Member); Jun- Ki Choi (Committee Member); Robert Brecha (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

Thermal Imaging, Multispectral, R-value,Data mining

Worsham, MatthewCarbon Lock-in and Decarbonization Pathways at the University of Dayton
Master of Science (M.S.), University of Dayton, 2017, Renewable and Clean Energy
Despite the availability of cost-effective alternatives to highly carbon-intensive practices, the world continues to invest in fossil fuel energy systems. For universities that have pledged to become carbon neutral, this concept of carbon lock-in raises the stakes of their carbon commitments, presenting challenges to traditional practices in facilities planning and operations. Building upon past research on carbon lock-in effects on college campuses, this thesis seeks to identify the University of Dayton’s over-committed emissions under a business-as-usual scenario and chart out a course for decarbonization pathways that would unlock those emissions that are hardest to avoid. I find the business-as-usual scenario results in high carbon liability at the neutrality date, which represents high costs to offset carbon emissions or purchase other “end-of-pipe” solutions. I also discuss decarbonization pathways that could unlock these over-committed emissions. Future work should explore some of the carbon unlocking strategies discussed here so the university can begin to integrate them into its climate action plan and construction policies. Additionally, this perspective on carbon lock-in will be useful to administrators and facilities managers at other institutions concerned about carbon neutrality and high carbon liabilities associated with existing and future carbon-emitting infrastructure.

Committee:

Robert Brecha, PhD (Advisor); Kevin Hallinan, PhD (Committee Member); Jun-Ki Choi, PhD (Committee Member)

Subjects:

Climate Change; Engineering; Mechanical Engineering; Sustainability

Keywords:

carbon lock-in; climate commitment; social cost of carbon; higher education; over-committed emissions; carbon accounting; emissions scenarios; facilities management; american college and university presidents climate commitment; decarbonization pathways

Reser, Kristen M.Perfectionism and anxiety: Is there a difference between high-ability students and their peers?
Master of Arts (M.A.), University of Dayton, 2016, Psychology, Clinical
Giftedness, defined as possessing abilities that fall in the top 10 percent, can be associated with risk factors that lead to perfectionism. High expectations on gifted students may lead to socially-prescribed perfectionism, a type of “negative” perfectionism, which is associated with anxiety. The present study examined the relationship between high ability students (members of the University Honors Program, or previously identified as gifted), dimensions of perfectionism, and types of anxiety. Honors/gifted participants were compared with their non-Honors/gifted peers. Eighty-two participants (22 male, 60 female) were recruited; 37 were members of the University Honors Program, and 31 reported having been identified as gifted. Participants completed an anagram task to mimic a stressful classroom situation and their pulses were measured before and after the anagram task as a manipulation check. Participants completed the State-Trait Anxiety Inventory, the Test Anxiety Inventory, and the Multidimensional Perfectionism Scale. No relationship was found between Honors program membership and State or Trait anxiety. Non-Honors students reported more test anxiety than Honors student (p = 0.01). No differences were found between the two groups on the dimensions of perfectionism. Likewise, no differences were found when gifted students were compared to non-gifted students on the same measures. Future research is needed to examine the relationship of perfectionism and high-ability, as this study used Honors students and not exclusively gifted students.

Committee:

Keri Kirschman, Ph.D. (Committee Chair); Lee Dixon, Ph.D. (Committee Member); Erin O'Mara, Ph.D. (Committee Member)

Subjects:

Psychology

Keywords:

Perfectionism; giftedness; state anxiety; trait anxiety; test anxiety; Honors students

Minix, Matthew GlenMid-Twentieth Century Neo-Thomist Approaches to Modern Psychology
Doctor of Philosophy (Ph.D.), University of Dayton, 2016, Theology
This dissertation considers a spectrum of five distinct approaches that mid-twentieth century neo-Thomist Catholic thinkers utilized when engaging with the tradition of modern scientific psychology: a critical approach, a reformulation approach, a synthetic approach, a particular [Jungian] approach, and a personalist approach. This work argues that mid-twentieth century neo-Thomists were essentially united in their concerns about the metaphysical principles of many modern psychologists as well as in their worries that these same modern psychologists had a tendency to overlook the transcendent dimension of human existence. This work shows that the first four neo-Thomist thinkers failed to bring the traditions of neo-Thomism and modern psychology together to the extent that they suggested purely theoretical ways of reconciling them. Finally, this work concludes that a personalist approach to modern psychology that locates the reconciliation of these two traditions within the practice of individual human beings rather than within a theoretical dialogue between the traditions themselves has the potential to succeed where theoretical neo-Thomist accounts of these traditions failed.

Committee:

Sandra Yocum, Ph.D. (Committee Chair); William Portier, Ph.D. (Committee Member); Anthony Smith, Ph.D. (Committee Member); John Inglis, Ph.D. (Committee Member); Jack Bauer, Ph.D (Committee Member)

Subjects:

Theology

Keywords:

Neo-Thomist approaches to modern psychology; Neo-Thomist psychology in the 20th century; spectrum of Thomist psychology; American Thomist responses to psychology;

Basunia, MahmudunnabiA Recursive Phase Retrieval Technique Using Transport of Intensity: Reconstruction of Imaged Phase and 3D Surfaces
Doctor of Philosophy (Ph.D.), University of Dayton, 2016, Electrical and Computer Engineering
Transport of intensity is a noninterferometric method to find the phase of an object by recording optical intensities at different distances of propagation. The transport of intensity equation results from the imaginary part of the complex paraxial wave equation and is equivalent to the principle of conservation of energy. The real part of the paraxial wave equation gives the eikonal equation in the presence of diffraction, which can be also termed the transport of phase equation. The amplitude and phase of the optical field must simultaneously satisfy both the real and imaginary parts of the paraxial wave equation during propagation. In this dissertation, it is demonstrated, using illustrative examples, how to exploit this to retrieve the phase through recursive calculations of the phase and intensity. This is achieved using the transport of intensity equation which is solved using standard Fourier transform techniques and the transport of phase equation, which is solved using a Gauss-Seidel iterative method. Examples include calculation of the imaged phase induced through self-phase modulation of a focused laser beam in a liquid, and the imaged phase of light reflected from a surface which yields its 3d surface profile.

Committee:

Partha Banerjee (Advisor); Guru Subramanyam, (Committee Member); Monish Chatterjee, (Committee Member); Youssef Raffoul, (Committee Member)

Subjects:

Electrical Engineering; Optics

Keywords:

TPE, TIE, Transport of Intensity, Transport of Phase, Recursive

Palanisamy, AshaHigh Energy Density Battery for Wearable Electronics and Sensors
Master of Science (M.S.), University of Dayton, 2016, Electrical Engineering
Wearable electronics and sensors are being extensively developed for several applications such as health monitors, watches, wristbands, eyeglasses, socks and smart clothing. Energy storage devices such as rechargeable batteries make wearable devices to become more independent from power outlets, or in other words, make device portability. Battery energy density determines how long a battery powered device will work before it needs a recharge. Longer the time before battery needs recharge, better it is for device applications. Therefore, the goal of battery researchers and engineers is to develop a battery that can provide high energy density and longer device operation. The state-of-the-art battery is the lithium-ion battery (LIB) technology outperforming any other battery for the aforementioned applications. Even LIB is limited in energy storage (energy density ~200 Wh/kg) and requires frequent battery charge. Some other major challenges associated with LIBs are high cost, low cycle life (restricted to 500 – 1000 cycles), safety, and negative environmental impacts. Further improvement in LIB is very limited as the technology is reaching the theoretical limit and therefore new battery technology with greater energy density and overall better performance must be developed in order to match the ever increasing power demand in fast growing electronics. Lithium sulfur battery (LSB) (energy density ~2600 Wh/kg) is one of the most promising batteries for next generation energy storage, enabling approximately 10 times more energy storage in LSB than LIB. Furthermore, sulfur is inexpensive, abundant and environmental friendly. Therefore, LSB is expected to be more economical, safe and environmentally sustainable compared to LIB. However, performance (cycle life, thermal stability and safety) of current LSB technology do not meet commercialization standards at current development stage and thus, open for further technological advancements. My thesis focuses on the development of novel materials that when successfully developed will improve the overall performance of LSB and can meet commercialization standards by combining thermal and dendrite-proof solid ion conducting ceramic based electrolyte (no liquid spillage) along with solid state and flexible S-cathode being developed in the Electrochemical Energy Systems Laboratory at the University of Dayton Research Institute (UDRI) of University of Dayton (UD).

Committee:

Guru Subramanyam (Committee Chair); Jitendra Kumar (Committee Co-Chair)

Subjects:

Electrical Engineering

Keywords:

Lithium sulfur; high energy density; battery for wearables; LAGP; S-cathode; CNT substrate

Romero, Michael AnthonyThe Laying on of Hands and the Building Up of the Catholic Charismatic Movement
Master of Arts (M.A.), University of Dayton, 2016, Theological Studies
The Catholic Charismatic Movement, inheriting the use of the laying on of hands from the Neo-Pentecostal movement, was able to grow and flourish because the laying on of hands was seen as a channel by which one could experience a spiritual renewal. The Catholic Charismatic Movement’s own rationale behind the use of the laying on of hands has fallen short in assessing its value during the early growth of the movement. The appraisal of the laying on of hands as a symbolic gesture or a sacramental is challenged in this study, and a new interpretation of the use of the laying on of hands is offered: the laying on of hands is a charism that built up the Catholic Charismatic Movement. The personal spiritual journeys of William Storey and Ralph Keifer are analyzed to understand what led them to their encounter with the Protestant Pentecostal prayer group, where the Catholics first received the baptism in the Spirit by the laying on of hands. The subsequent “Duquesne Weekend” retreat and the growth of the movement on the campus of Notre Dame are also studied in respect to the prevalent use of and the sought-after nature of the laying on of hands. My interpretation of the laying on of hands as a charism relies on the pneumatology of Heribert Muhlen. Muhlen’s description of the Church as the continuation of the anointing of Jesus with the Spirit, and his understanding of the Spirit as the divine self-giving supports the idea that in the laying on of hands the two parties are surrendering to the church and the Spirit. Ultimately, the laying on of hands in this context is a charism for the community where the public witness of the act edifies and strengthens.

Committee:

Sandra Yocum, Ph.D. (Advisor); Meghan Henning, Ph.D. (Committee Member); Dennis Doyle, Ph.D. (Committee Member)

Subjects:

Biblical Studies; History; Religion; Theology

Keywords:

laying on of hands; renewal; catholic charismatic movement; william storey; ralph keifer; pentecostalism; Heribert Muhlen; duquesne weekend; charism; sacramentals; jervell; acts 8; wolfgang vondey; baptism in the Spirit; pneumatology; trinity; Laurentin;

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