Physical Sciences and Mathematics Commons^™

Provenance, Redox Conditions, And Diagenesis Of Shales In Chang 7 Member Of Upper Triassic Yanchang Formation, Ordos Basin, China, Bin Sun

Doctoral Dissertations

“This study aims to decipher provenance, redox conditions, and burial history of shales in Chang 7 Member of Upper Triassic Yanchang Formation, Ordos Basin, China. The first paper discusses the origins of single-channeled, vertical, sinuous, and calcite-bitumen-filled cracks in the shales. Results show that in early diagenesis, unconsolidated mud was expanded open by escaping gases produced during organic matter maturation under hydrothermal influences. Calcite initially filled the cracks; bitumen and pyrite came in later and occupied the cracks in various ways. Compaction occurred next and folded the calcite- and bitumen-filled cracks into sinuous shapes. The second paper uses geochemical and …

Mass Spectrometry Analysis Of Contaminants Of Emerging Concern: Nanoparticles, Algal Toxins, And Cyanotoxins In Natural Waters And Their Potential Health Impacts, Ariel R. Donovan

Doctoral Dissertations

“The analysis of contaminants of emerging concern is critical to protecting environmental health. In the presented dissertation, two groups of contaminants of emerging concern were assessed using mass spectrometry methods: nanoparticles and algal and cyanotoxins.

Analysis of metal oxide nanoparticles in environmental matrices has been a challenging issue, as most traditional methods require complicated sample preparation methods or that can alter or destroy the nanoparticles in the system. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) methods were used to detect metal oxide nanoparticles in surface waters and their removal through drinking water treatment simulations while retaining all information regarding …

Design, Synthesis, Characterization And Anti-Cancer Effects Evaluation Of Interchain Cysteine Linked Antibody Drug Conjugates, Ke Li

Doctoral Dissertations

"Antibody drug conjugates (ADCs) are emerging therapeutic products specially designed for the treatment of cancers. Potent cytotoxic agents are linked to antibodies via linkers. Antibody drug conjugates, which take advantage of both antibodies and cytotoxic agents, showed high selectivity towards cancer cells. Cytotoxic agents are delivered to the cancer cells selectively and kill them from inside while leaving low or non-toxicity towards normal cells. Antibody drug conjugates are actually heterogeneous mixtures. The major heterogeneities mainly lie in the drug to antibody ratio (DAR) and drug linking positions, both of which potentially affect the therapeutic index of ADCs. In this research, …

The Benefit Of Precise Chemical Shift And Concentration Referencing In Nmr Applications, Ming Huang

Doctoral Dissertations

“In Nuclear Magnetic Resonance (NMR) spectroscopy, the chemical shift and intensity of NMR signals provide critical information about a sample's molecular structure, reaction conditions, and material properties. For the precise determination of structures and properties, it is critical to know sample or reaction conditions such as temperature, pH, concentration, or absolute amount of material. Chemical-shift and signal-intensity calibrations play a key role for extracting the maximum amount of information from NMR experiments. In this dissertation, internal and external reference standards are used to calibrate NMR spectra with respect to chemical shift and signal intensity. Sealed capillary tubes filled with specific …

Characterization Of A Green Electric Solid Propellant For Electric Propulsion, Matthew Scott Glascock

Doctoral Dissertations

"Electric solid propellants are advanced solid chemical rocket propellants that can be controlled (ignited, throttled and extinguished) through the application and removal of an electric current. These propellants are also being considered for use in ablative pulsed plasma thruster and multimode systems. In this work, the behavior and performance of a novel green electric solid propellant operating in an electrothermal ablation-fed pulsed plasma thruster was investigated. Using an inverted pendulum micro-Newton thrust stand, the impulse bit and specific impulse of the device using the electric solid propellant were measured for short-duration and long-duration runs to end-of-life, at energy levels of …

Modeling Of Hiv, Sir And Sis Epidemics On Time Scales And Oscillation Theory, Gülşah Yeni

Doctoral Dissertations

"We study higher dimensional systems of first order dynamic equations on time scales together with their applications. In particular, we focus on epidemic models such as HIV (Human Immunodeficiency Virus), SIS (Susceptible-Infected-Susceptible) and SIR (Susceptible-Infected-Recovered).

First, we generalize the early studied continuous three dimensional linear model of drug therapy for HIV-1 decline on time scales in order to derive new discrete models that predict the total concentration of plasma virus as a function of time. We compare these models to explore the impact of the theory of time scales. After fitting the models to the data collected at a clinical …

Paleoenvironment And Paleoclimate Of Ne Pangea In Early Permian-Linking Chemo- And Cyclo-Stratigraphy, Bogda Mountains, Nw China, Xin Zhan

Doctoral Dissertations

"The overall objective of this study is to understand physical and chemical responses of Earth Systems to environmental and climatic perturbations of diverse magnitudes and time scales in Bogda Mountains, NE Pangea. Field investigations, petrographic observations, and geochemical analyses have been used to interpret paleoenvironment and paleoclimate in cm-m-scale high-order cycles (HCs: 0.1-100 kyrs), low-order cycles (LCs: 1-10 Myr), and critical events of late Paleozoic ice age (LPIA: 320-260 Myr ago). Four organo-facies are one-to-one correlated with the four lithofacies in the meter-scale HCs, suggesting litho- and organo-facies are genetically linked and fundamentally controlled by environmental changes associated with lake …

Investigating Blast Fume Propagation, Concentration And Clearance In Underground Mines Using Computational Fluid Dynamics (Cfd), Raymond Ninnang Tiile

Doctoral Dissertations

"Blasting activities using standard industry explosives is an essential component of underground hard rock mining operations. Blasting operations result in the release of noxious gases, presenting both safety and productivity threats. Overestimation of post-blast re-entry time results in production losses, while underestimation leads to injuries and fatalities. Research shows that most underground mines simply standardize post-blast re-entry times based on experiences and observations. Few underground mines use theoretical methods for calculating post-blast re-entry time. These theoretical methods, however, are unable to account for the variations in the blasting conditions. Literature review shows that: (i) there is currently no means of …

Privacy Preservation In Social Media Environments Using Big Data, Katrina Ward

Doctoral Dissertations

"With the pervasive use of mobile devices, social media, home assistants, and smart devices, the idea of individual privacy is fading. More than ever, the public is giving up personal information in order to take advantage of what is now considered every day conveniences and ignoring the consequences. Even seemingly harmless information is making headlines for its unauthorized use (18). Among this data is user trajectory data which can be described as a user's location information over a time period (6). This data is generated whenever users access their devices to record their location, query the location of a point …

High Level Thermochemical And Spectroscopic Computations For Molecules Relevant To Combustion And The Atmosphere, Bradley K. Welch

Doctoral Dissertations

"Computational thermochemistry can be a complicated multistep process, but in recent years has become an equal partner with experiment. Many important molecules in combustion systems or in the atmosphere (such as short-lived radicals) are difficult to study experimentally. Predicting highly accurate thermochemistry is a key aspect in understanding these species. In this project, computational thermochemistry was developed into an automated streamlined procedure and then used to understand the methyl and ethyl peroxy families of radicals. This effort involved optimizing a standard workflow for computational thermochemistry. Computational thermochemistry generally requires numerous individual calculations whose cost and scalings vary widely. Conducting such …

Receiver Function Investigations Of Mantle Transition Zone And Crustal Structure In East Africa And Northeast Asia, Muchen Sun

Doctoral Dissertations

"In spite of numerous geophysical studies have been conducted in East Africa and Northeast Asia, the structure and evolution of the crust, upper mantle, and the mantle transition zone (MTZ) are still controversial. The MTZ discontinuities beneath the study area are imaged by stacking an unprecedented volume of receiver functions (RFs). The normal MTZ thickness beneath the Western Branch of the EARS and Tanzania Craton indicates the absence of present-day thermal upwelling from the lower mantle. In contrast, beneath the Eastern Branch, a significant MTZ thinning reveals the existence of thermal upwelling from either the upper MTZ or the lower …

Electrodeposition Of Epitaxial Metal Thin Films On Silicon For Energy Conversion And Flexible Electronics, Qingzhi Chen

Doctoral Dissertations

"This research focuses on epitaxial electrodeposition of two coinage metals: Au and Ag thin films on the silicon surface and their applications in flexible electronics and energy conversion and storage. The first paper: Photoelectrochemistry of ultrathin, semi-transparent, and catalytic gold films electrodeposited epitaxially onto n-silicon (111) describes the epitaxial electrodeposition of Au thin films on n-type Si using a simple HAuCl4 bath and the photoelectrochemical properties of the Au-Si junction barrier. The effect of the Au layer on the interfacial energetics as well as the stability of the photoelectrode as a function of the Au coverage/thickness is determined in a …

Nanomorphology Dependent Optical And Mechanical Properties Of Aerogels, Chandana Mandal

Doctoral Dissertations

"Aerogels are very low density, light weight open pore materials. A hypothesis that is under intense current investigation by the scientific community states that the mechanical properties of nanostructured polymers depend on their nanomorphology. Aerogels are nanostructured ultra-lightweight nanoporous materials with skeletal frameworks that can display a wide range of nanomorphologies. Thereby aerogels comprise a suitable platform for testing not only that hypothesis but also a wide range of other properties such as light scattering for applications, for example, in thermally insulating windows.

To study the mechanical properties of nanostructured matter as a function of nanomorphology, various shape-memory polyurethane aerogels …

Origin Of Periclines In The Ozark Plateau, Missouri: A Field And Numerical Modeling, Chao Liu

Doctoral Dissertations

"A series upright sub-horizontal folds in sandstones of the early Ordovician Roubidoux Formation are exposed in road cuts along US Highway 63 in the northern part of the Salem Plateau of central Missouri for over a distance of approximately 10 km. These folds are in marked contrast to the more typical horizontal to sub-horizontal Ordovician strata of the Ozark Plateau. The origin of those folds remains enigmatic. The inspection of the characteristics of these folds using stereographic analysis revealed a non-cylindrical geometrical pattern than a near cylindrical fold. Structural data of 54 folds indicate an alternating basin and dome pattern. …

Accurate Monitoring Of X, Y, And Z Magnetization For Analysis Of Hardware And Pulse Sequence Performance In Nmr Spectroscopy, Emmalou Theresa Schmittzehe

Doctoral Dissertations

"A new nuclear magnetic resonance (NMR) imaging protocol has been developed to independently record the x, y, and z components of the nuclear net magnetization at any point in a pulse sequence while eliminating the observation of the other components. This protocol provides an experimental method of tracking magnetization which then can be used in conjunction with theoretical models to scrutinize the predicted outcome of each step in an NMR pulse sequence and potentially find further improvements to their effectiveness and efficiency. The protocol utilizes a rapid rotating-frame imaging pulse-train technique to obtain RF-field (B₁) and resonance-offset (ΔB …

Deep Neural Network Learning-Based Classifier Design For Big-Data Analytics, Krishnan Raghavan

Doctoral Dissertations

"In this digital age, big-data sets are commonly found in the field of healthcare, manufacturing and others where sustainable analysis is necessary to create useful information. Big-data sets are often characterized by high-dimensionality and massive sample size. High dimensionality refers to the presence of unwanted dimensions in the data where challenges such as noise, spurious correlation and incidental endogeneity are observed. Massive sample size, on the other hand, introduces the problem of heterogeneity because complex and unstructured data types must analyzed. To mitigate the impact of these challenges while considering the application of classification, a two step analysis approach is …

Fault Imaging Enhancement In Taranaki Basin, New Zealand And Rock Physics And Inversion Based Reservoir Characterization In The Central Gulf Coast Region Of Texas, Tianze Zhang

Doctoral Dissertations

"Fault imaging technique and reservoir characterization based on rock physics analysis and pre-stack inversion has been widely used hydrocarbon exploration. For the fault imaging technique, the ant tracking has been widely used in fault interpretation. However, the reliability of the results is highly dependent on appropriately choosing a signal processing method and volume attributes. In our study area, which lies in the southern Taranaki Basin, we applied Graphic Equalizer as the processing tool and the Chaos attribute before running the ant tracking algorithm. Results show that the procedure provides a better result and can map both the major and minor …

Three-Dimensional Nanotube Arrays For Solar Energy Harvesting And Production Of Solar Fuels, Wipula P. R. Liyanage

Doctoral Dissertations

"Over the past decade extensive research has been carried out on photovoltaic semiconductors to provide a solution towards a renewable energy future. Fabricating high-efficiency photovoltaic devices largely rely on nanostructuring the photoabsorber layers due to the ability of improving photoabsorption, photocurrent generation and transport in nanometer scale. Vertically aligned, highly uniform nanorods and nanowire arrays for solar energy conversion have been explored as potential candidates for solar energy conversion and solar-fuel generation owing to their enhanced photoconversion efficiencies.

However, controlled fabrication of nanorod and especially nanotube arrays with uniform size and shape and a pre-determined distribution density is still a …

Novel Statistical Modeling Of Sleep Patterns In Drosophila Melanogaster, Luyang Wang

Doctoral Dissertations

”Sleep is one of the most important behaviors in animals, yet many aspects of sleep are not well understood. In humans, sleep has been shown to impact different aspects of health and cognitive performance. The fruit fly, Drosophila melanogaster, can be used as a model organism to investigate sleep patterns over an entire lifespan. The sleep-wake status can be recorded every minute over the life of individual flies, resulting in a wealth of data for identifying meaningful aspects of sleep. In this work, a framework based on statistical modeling methods is developed for sleep data collected on fruit flies …

Volumetric Error Compensation For Industrial Robots And Machine Tools, Le Ma

Doctoral Dissertations

“A more efficient and increasingly popular volumetric error compensation method for machine tools is to compute compensation tables in axis space with tool tip volumetric measurements. However, machine tools have high-order geometric errors and some workspace is not reachable by measurement devices, the compensation method suffers a curve-fitting challenge, overfitting measurements in measured space and losing accuracy around and out of the measured space. Paper I presents a novel method that aims to uniformly interpolate and extrapolate the compensation tables throughout the entire workspace. By using a uniform constraint to bound the tool tip error slopes, an optimal model with …

Development Of A Switchable Radioisotope Generator, Kyle Mitchell Paaren

Doctoral Dissertations

The Switchable Radioisotope Generator utilizes alpha-induced reactions to produce a combination of photons, neutrons, and protons with varying fluxes dependent on target materials and source geometry. The activity/strength of the secondary radiation is further controlled by manipulating the number of alpha particles that can interact with the target material(s). Analytical equations were solved to confirm secondary radiation production from target materials using average cross sections from TENDL data. TENDL and JENDL data was confirmed by analytically solving for the total alpha-induced cross sections. This information was used to produce the provisional and utility Patent No: US20190013109A1. TENDL data was then …

Ferrite Characterization Techniques & Particle Simulations For Semiconductor Devices, Nicholas Erickson

Doctoral Dissertations

"This dissertation is divided into three papers, covering two major topics. The first topic, techniques for ferrite characterization, is discussed over the course of two papers. The second topic, particle simulations for semiconductor devices, is discussed in the last paper. In the first paper, the method for extracting permeability from ferrite materials is discussed for the Keysight 16454A permeability extraction fixture, where the ferrite material to be characterized is assumed to be homogeneous. Then the method is updated to account for layered materials. The updated method is verified through full-wave simulations. In the second paper, a planar printed circuit board …

Reliability Analysis For Systems With Outsourced Components, Zhengwei Hu

Doctoral Dissertations

"The current business model for many industrial firms is to function as system integrators, depending on numerous outsourced components from outside component suppliers. This practice has resulted in tremendous cost savings; it makes system reliability analysis, however, more challenging due to the limited component information available to system designers. The component information is often proprietary to component suppliers. Motivated by the need of system reliability prediction with outsourced components, this work aims to explore feasible ways to accurately predict the system reliability during the system design stage. Four methods are proposed. The first method reconstructs component reliability functions using limited …

The Dynamical State Of A Young Stellar Cluster, Timothy Sullivan

Doctoral Dissertations

"The dynamical state of the young star-forming cluster Rho Ophiuchi is considered, with emphasis on the L1688 cloud. Radial velocities are derived for 32 YSOs, with some being multi-epoch, using Markov-Chain Monte Carlo routines based upon the package emcee. Sources are chosen based upon their spectral index to focus on the earlier stages of star formation, in this case, Class I and Flat spectrum objects, and compared with a sample of Class II and III objects from the same embedded cluster. It is found that the radial velocity dispersion for these younger objects is Δv = 2.8 ± 0:6 …

Pressure Versus Impulse Graph For Blast-Induced Traumatic Brain Injury And Correlation To Observable Blast Injuries, Barbara Rutter

Doctoral Dissertations

"With the increased use of explosive devices in combat, blast induced traumatic brain injury (bTBI) has become one of the signature wounds in current conflicts. Animal studies have been conducted to understand the mechanisms in the brain and a pressure versus time graph has been produced. However, the role of impulse in bTBIs has not been thoroughly investigated for animals or human beings.

This research proposes a new method of presenting bTBI data by using a pressure versus impulse (P-I) graph. P-I graphs have been found useful in presenting lung lethality regions and building damage thresholds. To present the animal …

Provenance And Depositional Environments Of The Upper Permian-Lowermost Triassic Fluvial And Lacustrine Sandstones, Wutonggou Low-Order Cycle, Bogda Mountains, Nw China, Dongyu Zheng

Doctoral Dissertations

"This work integrates petrographic and fieldwork studies and documents the spatial and temporal distributions of compositions and textures of the upper Permian-lowermost Triassic fluvial-lacustrine sandstones, Wutonggou low-order cycle (WTG LC), Bogda Mountains, NW China. In the first part, three petrofacies are identified on the basis of the relative abundances of quartz, feldspar, and lithics and conglomerate compositions and paleocurrent directions are documented. These data indicate that rocks of the eastern North Tianshan Suture (ENTS) and rift shoulders were the provenance lithology. Moreover, the upsection changes of petrofacies and conglomerate compositions suggest that the lithology of ENTS changed. During approximately Wuchiapingian, …

Coherent Effects In Wave Propagation Through Complex Media, Milan Koirala

Doctoral Dissertations

"Diffusion is a powerful and versatile description of a typical wave propagation in a random scattering medium that disregards phase and, thus, a possibility of interference. Speckle, transmission fluctuations, wave localization, non-local correlations, and transmission eigenchannels are examples of persistent interference effects, which arise in the course of deterministic propagation. Such wave phenomena contain a wealth of information about the medium and the source of waves, enabling sensing and coherent control of the propagation. The nonlocal correlations and speckle statistics of the partially coherent light are used to uncover an object hidden by a diffusive cloak inside a strong scattering …

Synthesis And Applications Of Ceramic (Silicon Carbide And Silicon Nitride), Metallic (Cobalt(0)) And Polymeric (Polyurethane) Aerogels, Parwani M. Rewatkar

Doctoral Dissertations

"A new method has been demonstrated for the synthesis of monolithic ceramic and purely metallic aerogels from xerogel powder compacts, and the use of polyurethane aerogels based on cyclodextrins as efficient desiccants.

I. Highly porous ( > 80%) monolithic SiC and Si₃N₄, aerogels were prepared from compressed compacts of polyurea-crosslinked silica xerogel powders. The process is time efficient as solvent-exchange through powders is fast, and energy efficient as it bypasses drying with supercritical fluids. The final ceramic objects were chemically pure, sturdy, with compressive moduli at 37 ±7 MPa and 59 ± 7 MPa, and thermal conductivities …

Polyurea Aerogels: From Nanoscopic To Macroscopic Properties, Tahereh Taghvaee

Doctoral Dissertations

"The morphology of a material is intrinsically a qualitative property and in order to relate nanomorphology to synthetic conditions, it is necessary to express nano/micro-structure quantitatively. In this context, polyurea aerogels were chosen as a model system with demonstrated potential for rich nanomorphology and being guided by a statistical Design-of-Experiments model, a large array of materials (208) with identical chemical composition, but quite different nanostructures were prepared. By reflecting upon the SEM images, it was realized that our first pre-verbal impression about a nanostructure is related to its openness and texture; the former is quantified by porosity (Π), and the …

Decoding The History Of The Early Solar System Using Comet Volatile Compositions, Nathaniel Xavier Roth

Doctoral Dissertations

"Understanding the evolution of the solar system, as well as its current volatile content, requires knowledge of the initial conditions present in the solar nebula. As some of the first objects to accrete in the solar nebula, cometary nuclei are among the most primitive remnants of solar system formation, and their present-day volatile composition likely reflects the composition and conditions where (and when) they formed. As such, the volatile compositions of cometary nuclei may serve as 'fossils' of solar system formation. High-resolution near-infrared spectroscopy offers a valuable tool for sampling the primary volatile (i.e., ices subliming directly from the nucleus) …