Physical Sciences and Mathematics Commons^™

The Pilot Knob Magnetite, Pilot Knob Hematite, And Shepherd Mountain Iron Oxide Deposits In Southeast Missouri -- Local Expressions Of A Magmatic-Hydrothermal Plumbing System?, Bolorchimeg N. Tunnell

Doctoral Dissertations

“The Southeast Missouri Iron Metallogenic Province in the Midwestern USA contains seven major and several minor IOA/IOCG-type deposits, all of which are spatially associated with the early Mesoproterozoic (1.50-1.44 Ga) magmatism in the St. Francois Mountains terrane. This Ph.D. project focuses on the Pilot Knob deposits, i.e., the deeper largely massive Pilot Knob Magnetite (PKM) and the shallower Pilot Knob Hematite (PKH) deposits, and the Shepherd Mountain deposit that are located less than 2.1 km distance from one another. The first precise age for the formation of the PKM ore is constrained at 1438±5.8 Ma using apatite U-Pb method. Petrographic …

Preclassic Cultural Eutrophication Of Lake Petén Itzá, Lowland Guatemala, By The Early Maya Of Nixtun-Ch'ich', Brooke A. Birkett

Masters Theses

"Paleolimnological evidence indicates the ancient Maya transformed lowland terrestrial ecosystems by felling forest vegetation to construct large civic-ceremonial centers and expand agriculture. The effects of prehistoric Maya land alterations on lake trophic status, however, remain poorly understood. We analyzed a 515-cm-long sediment core from Lake Petén Itzá, lowland Guatemala, to infer paleoenvironmental changes resulting from Maya occupation of the riparian archaeological site of Nixtun-Ch'ich'. Substantial increases in charcoal and fecal stanol concentrations indicate Maya occupation of the Candelaria Peninsula by the late Early Preclassic period beginning ca. 1400 cal yr Before the Common Era (hereafter BCE), despite scant archaeological evidence …

Predator Scent And Presence Alter Mammal Assemblages In The Missouri Ozarks, Usa, Cara Jean Yocom-Russell

Masters Theses

"Species that are vulnerable to predation exhibit a host of behavioral and physiological adaptations toward the avoidance of this outcome: Heightened awareness of surroundings through visual, olfactory, and auditory senses are common ways in which these species avoid detection by predators. While links between direct predator-prey relationships are well established, less is known about how predators can shape overall community structure or the populations of secondary or less frequently consumed prey items. As humans expand into rural areas, the frequency of wildlife conflicts rises. In response, humans look to prevent these events with a variety of methods. One such method …

Crustal And Upper Mantle Structure Beneath The Southeastern United States From Joint Inversion Of Rayleigh Wave Dispersion And Receiver Functions, Qiuyue Yang

Doctoral Dissertations

"In spite of numerous geophysical investigations have been conducted in southeastern United States, the structure and evolution of the crust and lithospheric mantle remain controversial due the thick sedimentary covers atop the crust of the coastal plains there. In this study, we use data from 186 broadband seismic stations belonging to the USArray Transportable Array to construct a 3-D shear wave velocity model for the southeastern United States for the top 180 km by a joint inversion of Rayleigh wave phase velocity dispersion and receiver functions. Our results show a clear spatial correspondence with major surficial geological features. A prominent …

Fabrication, Characterization And Environmental Monitoring Of Polymer-Based Materials For Biomedical And Structural Applications, Mousumi Bose

Doctoral Dissertations

"Polymers are versatile materials utilized for variety of applications. In biomedical field, luminescence quenching based optical oxygen sensors encapsulated in polymeric substances are gaining attention for early detection of surface wounds associated with tissue oxygen. A simple and low-cost fabrication technique was developed to produce sensor arrays for continuous two-dimensional oxygen tension measurement. Sensor patch along with smart phone-based readout technique is being evaluated as a smart bandage.

The environmental concerns and limited petroleum supply demand for replacing petroleum-based polymers with renewable bio-based sources while maintaining comparable properties. A sustainable and green approach was adopted to synthesize soy polyol-derived rigid …

Modeling Time Series With Conditional Heteroscedastic Structure, Ratnayake Mudiyanselage Isuru Panduka Ratnayake

Doctoral Dissertations

"Models with a conditional heteroscedastic variance structure play a vital role in many applications, including modeling financial volatility. In this dissertation several existing formulations, motivated by the Generalized Autoregressive Conditional Heteroscedastic model, are further generalized to provide more effective modeling of price range data well as count data. First, the Conditional Autoregressive Range (CARR) model is generalized by introducing a composite range-based multiplicative component formulation named the Composite CARR model. This formulation enables a more effective modeling of the long and short-term volatility components present in price range data. It treats the long-term volatility as a stochastic component that in …

Receiver Function Imaging Of The 410 And 660 Km Discontinuities And Seismic Azimuthal Anisotropy Revealed By Shear Wave Splitting Beneath The Australian Continent, Kailun Ba

Doctoral Dissertations

"The Australian continent is composed the of Precambrian cratons in the west and Phanerozolc orogens in the east. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Australia. In this study, we used two techniques, receiver functions and shear wave splitting analyses, to investigate the topography of the mantle transition zone (MTZ) discontinuities and mantle seismic azimuthal anisotropy, respectively. We utilized P-to-S receiver functions to map the 410 and 660 km discontinuities bordering the MTZ. The discontinuity depths obtained show a systematic apparent uplifting for both discontinuities in central and western …

Improving The Data Quality In Gravitation-Wave Detectors By Mitigating Transient Noise Artifacts, Kentaro Mogushi

Doctoral Dissertations

“The existence of gravitational waves (GWs), small perturbations in spacetime produced by accelerating massive objects was first predicted in 1916 as solutions of Einstein’s Theory of General Relativity (Einstein, 1916). Detecting and analyzing GWs produced by sources allows us to probe astrophysical phenomena.

The era of GW astronomy began from the first direct detection of the coalescence of a binary black hole in 2015 by the collaboration of the advanced Laser Interferometer Gravitational-wave Observatory (LIGO) (Aasi et al., 2015) and advanced Virgo (Abbott et al., 2016a). Since 2015, LIGO-Virgo detected about 50 confident transient events of GW signals (Abbott et …

Critical Behavior In Evolutionary And Population Dynamics, Stephen Walter Ordway

Doctoral Dissertations

“This study is an exploration of phase transition behavior in evolutionary and population dynamics, and techniques for predicting population changes, across the disciplines of physics, biology, and computer science. Under the looming threat of climate change, it is imperative to understand the dynamics of populations under environmental stress and to identify early warning signals of population decline. These issues are explored here in (1) a computational model of evolutionary dynamics, (2) an experimental system of decaying populations under environmental stress, and (3) a machine learning approach to predict population changes based on environmental factors. Through the lens of critical phase …

Robustness Against Attacks And Uncertainties In Smart Cyber-Physical Systems, Prithwiraj Roy

Doctoral Dissertations

Cyber-Physical Systems (CPS) are sensing, processing, and communicating platforms, embedded with physical devices that provide real-time monitoring and control. Security challenges in CPS necessitate solutions that are robust against attacks and uncertainties and provide a seamless operation, especially when used in real-time applications to monitor and secure critical infrastructures. CPS mainly consists of a physical component for sensing or monitoring and a cyber component for processing and communicating. The quality of interactions between physical and cyber systems has direct impacts on the system’s performance and reliability.

CPS plays a major role in smart services and applications within a smart living …

Development Of High-Performance Hydrogels, Buddhabhushan Salunkhe

Doctoral Dissertations

Here, we present a systematic approach to design robust hydrogel compositions. The goal was to achieve excellent properties to open up new opportunities in especially two challenging applications not previously well-served by hydrogels.

The first part of this research will discuss the systematic screening of polymers for their hydrothermal stability under brine, acidic, neutral, and basic pH conditions followed by novel designs of hydrogel compositions. Certain hydrogel compositions withstand temperatures of up to 150 °C for more than 24 months in high salinity brines. This novel hydrogel composition fills a technology gap between the existing polyacrylamide-based preformed particle gels (PPGs) …

Secure Data Sharing In Cloud And Iot By Leveraging Attribute-Based Encryption And Blockchain, Md Azharul Islam

Doctoral Dissertations

“Data sharing is very important to enable different types of cloud and IoT-based services. For example, organizations migrate their data to the cloud and share it with employees and customers in order to enjoy better fault-tolerance, high-availability, and scalability offered by the cloud. Wearable devices such as smart watch share user’s activity, location, and health data (e.g., heart rate, ECG) with the service provider for smart analytic. However, data can be sensitive, and the cloud and IoT service providers cannot be fully trusted with maintaining the security, privacy, and confidentiality of the data. Hence, new schemes and protocols are required …

Development Of Intelligent Stimuli-Responsive Biomaterials And Nanodevices, Shuo Yang

Doctoral Dissertations

"Structural DNA nanotechnology utilizes DNA molecules as building blocks to fabricate ordered artificial nanostructures at the molecular level. Among all DNA-based techniques, DNA origami has been considered as one of the most powerful tools for constructing artificial nanostructures with excellent programmability and addressability. Currently, most DNA origami nanostructures are static and do not have the ability to response to environmental stimulation. The development of environmental-responsive DNA origami nanostructures is a critical step towards the realization of intelligent dynamic DNA origami-based nanodevices. This research focuses on the design and fabrication process of both static and dynamic DNA origami nanostructures and their …

Novel Synthetic Methods And Applications Of Porous Materials: Aerogel Foams, Metallic Aerogels, Amorphous And Graphitic Carbon Aerogels, Rushi Soni

Doctoral Dissertations

"We report novel methods for the synthesis of porous materials such as polymeric aerogel foams, pure metallic aerogels, amorphous and graphitic carbon aerogels, and their applications. I. Polyurethane based aerogel foams were synthesized with an aliphatic triisocyanate and ethylene glycol through a pressurized (7 bar) sol-gel method. The foam-like structure is prepared without any chemical foaming agents or templates, resulting in less expensive, more efficient, readily adaptable, and environmentally friendly process. Those materials exhibited lower thermal conductivity (by 25%) and higher oil adsorption capacity (by 36% w/w) than their corresponding aerogels. II. Monolithic, pure metallic Co(0) aerogels were synthesized from …

Computational Intelligent Impact Force Modeling And Monitoring In Hislo Conditions For Maximizing Surface Mining Efficiency, Safety, And Health, Danish Ali

Doctoral Dissertations

"Shovel-truck systems are the most widely employed excavation and material handling systems for surface mining operations. During this process, a high-impact shovel loading operation (HISLO) produces large forces that cause extreme whole body vibrations (WBV) that can severely affect the safety and health of haul truck operators. Previously developed solutions have failed to produce satisfactory results as the vibrations at the truck operator seat still exceed the “Extremely Uncomfortable Limits”. This study was a novel effort in developing deep learning-based solution to the HISLO problem.

This research study developed a rigorous mathematical model and a 3D virtual simulation model to …

Exposure Assessment Of Emerging Contaminants: Rapid Screening And Modeling Of Plant Uptake, Majid Bagheri

Doctoral Dissertations

"With the advent of new chemicals and their increasing uses in every aspect of our life, considerable number of emerging contaminants are introduced to environment yearly. Emerging contaminants in forms of pharmaceuticals, detergents, biosolids, and reclaimed wastewater can cross plant roots and translocate to various parts of the plants. Long-term human exposure to emerging contaminants through food consumption is assumed to be a pathway of interest. Thus, uptake and translocation of emerging contaminants in plants are important for the assessment of health risks associated with human exposure to emerging contaminants. To have a better understanding over fate of emerging contaminants …

Neogene Dinoflagellate Cysts From The Tropical Americas, Damian Cardenas

Doctoral Dissertations

"Marine palynomorphs, mainly dinoflagellate cysts and acritarchs, constitute excellent proxies for biostratigraphic and paleoceanographic studies in neritic sequences. Neogene marine palynological studies have mostly focused on the Northern Hemisphere, resulting in the scarcity of dinoflagellate cysts and acritarchs from tropical latitudes. Forty samples encompassing the late Chattian-late Burgidalian time interval (~24.1- 17.3 Ma) in the Southern Caribbean were analyzed for their marine palynological contents. A biostratigraphic scheme for the region is proposed and includes the upper Chattian-lower Aquitanian Minisphaeridium latirictum Interval Zone (~23.9-22.0 Ma), the upper Aquitanian Achomosphaera alcicornu Interval Zone (~22.0-20.3 Ma), and the Burdigalian Cribroperidinium tenuitabulatum Interval Zone …

Prediction Intervals For Fractionally Integrated Time Series And Volatility Models, Rukman Ekanayake

Doctoral Dissertations

"The two of the main formulations for modeling long range dependence in volatilities associated with financial time series are fractionally integrated generalized autoregressive conditional heteroscedastic (FIGARCH) and hyperbolic generalized autoregressive conditional heteroscedastic (HYGARCH) models. The traditional methods of constructing prediction intervals for volatility models, either employ a Gaussian error assumption or are based on asymptotic theory. However, many empirical studies show that the distribution of errors exhibit leptokurtic behavior. Therefore, the traditional prediction intervals developed for conditional volatility models yield poor coverage. An alternative is to employ residual bootstrap-based prediction intervals. One goal of this dissertation research is to develop …

Spatiotemporal Variations Of Upper Crustal Anisotropy Along The San Jacinto Fault Zone In Southern California And The Fairview Region In Central Oklahoma, Enyuan Jiang

Doctoral Dissertations

"To discern spatial and explore the possible existence of temporal variations of upper crustal anisotropy along an ~15 km section of the San Jacinto Fault Zone (SJFZ) in California, and in the Fairview, Oklahoma, region, we conduct systematic shear wave splitting (SWS) investigations using local S-wave data recorded by seismic stations. Strong spatial variations in crustal anisotropy are revealed by 1694 and 405 pairs of splitting parameters (including the fast polarization orientation and the splitting time), respectively. For both areas, for raypaths traveling through the fault zones, the fast orientations are parallel to the faults and may be attributed to …

Integrating Snp Data And Imputation Methods Into The Dna Methylation Analysis Framework, Yuqing Su

Doctoral Dissertations

"DNA methylation is a widely studied epigenetic modification that can influence the expression and regulation of functional genes, especially those related to aging, cancer and other diseases. The common goal of methylation studies is to find differences in methylation levels between samples collected under different conditions. Differences can be detected at the site level, but regulated methylation targets are most commonly clustered into short regions. Thus, identifying differentially methylated regions (DMRs) between different groups is of prime interest. Despite advanced technology that enables measuring methylation genome-wide, misinterpretations in the readings can arise due to the existence of single nucleotide polymorphisms …

Fiber Optic Sensors For Industry And Military Applications, Yiyang Zhuang

Doctoral Dissertations

"Fiber optic sensors (FOSs) have been widely used for measuring various physical and chemical measurands owing to their unique advantages over traditional sensors such as small size, high resolution, distributed sensing capabilities, and immunity to electromagnetic interference. This dissertation focuses on the development of robust FOSs with ultrahigh sensitivity and their applications in industry and military areas.

Firstly, novel fiber-optic extrinsic Fabry-Perot interferometer (EFPI) inclinometers for one- and two-dimensional tilt measurements with 20 nrad resolution were demonstrated. Compared to in-line fiber optic inclinometers, an extrinsic sensing motif was used in our prototype inclinometer. The variations in tilt angle of the …

Development Of Tripodal And Bipodal Ligand Frameworks And First-Row Transition Metal Reagents For Selective C-N Bond Construction Methodologies, Anshika Kalra

Doctoral Dissertations

"We present a family of anionic Mn(II) reagents supported by trisphenylamido- amlne frameworks that offer guidance with regards to ligand selection for developing C—N bond construction methodologies (extensively used in the synthesis of petrochemicals, household chemicals) through nitrene- transfer chemistry. We subsequently extend the study to include the corresponding Fe(II), Co(II), and Ni(II) reagents, to gain insights in their comparative reactivity/selectivity patterns. Attenuated levels of electrophilicity of anionic complexes proved to be more suitable for discriminating aromatic from aliphatic olefins for aziridination purposes, especially for Mn(II) complexes. However, in the case of Co(II) reagents, we observe that additional stereoelectronic parameters …

Proper Orthogonal Decomposition: New Approximation Theory And A New Computational Approach, Sarah Katherine Locke

Doctoral Dissertations

“Proper orthogonal decomposition (POD) projection errors and error bounds for POD reduced order models of partial differential equations have been studied by many. In this research we obtain new results regarding POD data approximation theory and present a new difference quotient (DQ) approach for computing the POD modes of the data.

First, we improve on earlier results concerning POD projection errors by extending to a more general framework that allows for non-orthogonal POD projections and seminorms. We obtain new exact error formulas and convergence results for POD data approximation errors, and also prove new pointwise convergence results and error bounds …

Analysis Of The Primary Volatile Compositions In The Oort Cloud And Jupiter-Family Comets Towards The Goal Of Understanding Their Origin And Diversity, Mohammad Saki

Doctoral Dissertations

“Knowledge of the initial conditions present in the early solar nebula is required to understand the evolution and its current volatile content. Comets were some of the first objects to accrete in the solar nebula. They are among the most pristine (primitive) remnants of the solar system formation, and their present-day volatile composition likely reflects the composition and conditions where (and when) they formed. Therefore, they are fossils of the solar system formation. High-resolution near-infrared spectroscopy is a valuable tool for sampling the parent volatile (i.e., ices subliming directly from the nucleus) composition of comets via analysis of fluorescence emission …

Reveal Wind Loading Of Tornadoes And Hurricanes On Civil Structures Towards Hazard-Resistant Design, Ryan Honerkamp

Doctoral Dissertations

"Extreme winds impacting civil structures lead to death and destruction in all regions of the world. Specifically, tornadoes and hurricanes impact communities with severe devastation. On average, 1200 tornadoes occur in the United States every year. Tornadoes occur predominantly in the Central and Southeastern United States, accounting for an annual $1 billion in economic losses, 1500 injuries, and 90 deaths. The Joplin, MO Tornado in 2011 killed 161 people, injured more than 1000, destroyed more than 8000 structures, and caused $2.8 billion of property loss. Hurricanes occur predominantly on the United States East coast regions and along the coast of …

Spatial Variations Of Teleseismic P-Wave Attenuation And Scattering Beneath The Southeastern United States And The Malawi And Luangwa Rift Zones In East Africa, Ashutosh Shrivastava

Doctoral Dissertations

"Seismic attenuation is an important physical parameter for characterizing subsurface morphology and the thermal structure of the Earth’s crust and mantle. In this study, teleseismic P-wave amplitude spectra are used to examine the seismic attenuation beneath the southeastern United States and the Malawi and Luangwa rift zones in east African. The resulting seismic attenuation parameters (Δt*) reveal a systematic contrast between the Appalachian Mountains and the Gulf of Mexico Coastal Plain exhibiting high and low attenuation, respectively. Spatial coherency analysis of the Δt* observations suggests that the center of the low-attenuation layer is located within the uppermost mantle at about …

Computational Studies Of Carbon Nanocluster Solidification, Chathuri Chandani Silva

Doctoral Dissertations

“A subset of micron-size meteoritic carbon particles formed in red giant atmospheres show a core-rim structure, likely condensed from a vapor phase into super-cooled carbon droplets that nucleated graphene sheets (~40Å) on randomly oriented 5-atom loops during solidification, followed by coating with a graphite rim. Similar particles form during slow cooling of carbon vapor in the lab.

Here we investigate the nucleation and growth of carbon rings and graphene sheets using density functional theory (DFT). Our objectives: (1). explore different computational techniques in DFT-VASP for various carbon structures and compare the results with literature, (2). investigate the nucleation and growth …

Mantle Flow Systems Associated With Slab Subduction And Absolute Plate Motion In Alaska Constrained By Shear Wave Splitting Analyses, Yuchen Yang

Doctoral Dissertations

"Alaska has long been recognized as a geologically complex region with a sharp contrast in tectonic activity between southern and northern Alaska. While the former is characterized by the subduction of the geometrically varying Pacific-Yakutat plate beneath the North American plate, the latter has a mostly stable cratonic setting. To investigate the mantle flow fields beneath Alaska and understand the influence of the subduction process on regional mantle dynamics, a total of 2790 pairs of well-defined teleseismic shear wave splitting (SWS) measurements recorded from 379 stations are obtained and analyzed. In addition, 247 pairs of SWS results from local earthquake …

Count Data Time Series Models And Their Applications, Yi Zhang

Doctoral Dissertations

“Due to fast developments of advanced sensors, count data sets have become ubiquitous in many fields. Modeling and forecasting such time series have generated great interest. Modeling can shed light on the behavior of the count series and to see how they are related to other factors such as the environmental conditions under which the data are generated. In this research, three approaches to modeling such count data are proposed.

First, a periodic autoregressive conditional Poisson (PACP) model is proposed as a natural generalization of the autoregressive conditional Poisson (ACP) model. By allowing for cyclical variations in the parameters of …

Complete Experiments On Multi-Photon Ionizations Of Ultra-Cold And Polarized Atoms, Bishnu Prasad Acharya

Doctoral Dissertations

“Fundamental atomic processes such as collision-induced ionization are of relevance in many scientific fields. Describing these reactions can still pose a substantial challenge due to the well-known “few-body problem”, which entails that there is no analytical solution of the equations of motion for systems of more the 2 mutually interacting particle. Novel experimental tools and advancements in theorical methods enable to obtain detailed information on atomic dynamics providing insight into both, the phase as well as the amplitude of the quantum-mechanical wave functions of the particles. In this project, we developed experimental techniques studying multi-photon ionization of lithium in femto-second …