Physical Sciences and Mathematics Commons^™

Simple Photochemical Reduction Of Carbon Dioxide To Formate, Ovuokenye Omadoko

Electronic Theses and Dissertations

There is a need to develop techniques for conversion of carbon dioxide to other useful products such as methanol, formaldehyde, formic acid, formate, methane, and hydrocarbons. Carbon dioxide can be converted into these products using different methods such as photochemical, electrochemical, thermochemical and hydrogenation by bacteria. Formate is of interest due to its wide industrial applications which include it’s use in direct liquid fuel cells, as an additive in pyrolysis vapors, a precursor for biological fuels, and it is a key intermediate in methanogenesis breaking down complex organic compounds. In this work, conversion of carbon dioxide to formate was accomplished …

Roman Domination Cover Rubbling, Nicholas Carney

Electronic Theses and Dissertations

In this thesis, we introduce Roman domination cover rubbling as an extension of domination cover rubbling. We define a parameter on a graph $G$ called the \textit{Roman domination cover rubbling number}, denoted $\rho_{R}(G)$, as the smallest number of pebbles, so that from any initial configuration of those pebbles on $G$, it is possible to obtain a configuration which is Roman dominating after some sequence of pebbling and rubbling moves. We begin by characterizing graphs $G$ having small $\rho_{R}(G)$ value. Among other things, we also obtain the Roman domination cover rubbling number for paths and give an upper bound for the …

Immobilization Of Electrocatalytically Active Gold Nanoparticles On Nitrogen-Doped Carbon Fiber Electrodes, Daniel Mawudoku

Electronic Theses and Dissertations

Studies of single, isolated nanoparticles provide better understanding of the structure-function relationship of nanoparticles since they avoid complications like interparticle distance and nanoparticle loading that are typically associated with collections of nanoparticles distributed on electrode supports. However, interpretation of results obtained from single nanoparticle immobilization studies can be difficult to interpret since the underlying nanoelectrode platform can contribute to the measured current, or the immobilization technique can adversely affect electron transfer. Here, we immobilized ligand-free gold nanoparticles on relatively electrocatalytically inert nitrogen-doped carbon ultramicroelectrodes that were prepared via a soft nitriding method. Sizes of the particles were estimated by a …

Robustness Of Semi-Parametric Survival Model: Simulation Studies And Application To Clinical Data, Isaac Nwi-Mozu

Electronic Theses and Dissertations

An efficient way of analyzing survival clinical data such as cancer data is a great concern to health experts. In this study, we investigate and propose an efficient way of handling survival clinical data. Simulation studies were conducted to compare performances of various forms of survival model techniques using an R package ``survsim". Models performance was conducted with varying sample sizes as small ($n5000$). For small and mild samples, the performance of the semi-parametric outperform or approximate the performance of the parametric model. However, for large samples, the parametric model outperforms the semi-parametric model. We compared the effectiveness and reliability …

Peroxide Sensing Using Nitrogen-Doped And Platinum Nanoparticle-Modified Screen-Printed Carbon Electrodes, Chidiebere Ogbu

Electronic Theses and Dissertations

Nitrogen-doped carbon materials have garnered much interest due to their abilities to behave as electrocatalysts for reactions important in energy production (oxygen reduction) and biosensing (hydrogen peroxide reduction). Here, we demonstrate fabrication methods and determine electrocatalytic properties of nitrogen-doped screen-printed carbon (N-SPCE) electrodes. Nitrogen doping of graphite was achieved through a simple soft-nitriding technique which was then used in lab-formulated screen-printing inks to prepare N-SPCEs. N-SPCEs displayed good electrocatalytic activity, reproducibility and long term stability towards the electrochemical reduction of hydrogen peroxide. N-SPCEs exhibited a wide linear range (20 µM to 5.3 mM), reasonable limit of detection of 2.5 µM, …

Modification Of Chemical Vapor-Deposited Carbon Electrodes With Electrocatalytic Metal Nanoparticles Through A Soft Nitriding Technique, Enoch Amoah

Electronic Theses and Dissertations

Metal nanoparticles have been widely used for many catalytic and electrocatalytic applications due to their larger surface area-to-volume ratios and higher densities of active sites compared to bulk materials. This has resulted in much interest in understanding the electrocatalytic behavior of metal nanoparticles with respect to their structure. However, most research on this topic has employed collections of nanoparticles. Due to difficulties in controlling and characterizing particle loading and interparticle distance in nanoparticle ensembles, single nanoparticles studies have recently become a topic of great interest. In this study, a soft nitriding technique was applied to chemical vapor-deposited carbon ultramicroelectrodes (UMEs) …

Debris-Slide Susceptibility Modelling Using Gis Technology In The Great Smoky Mountains National Park, Raja Das

Electronic Theses and Dissertations

Debris-slides are one of the most frequently occurring geological hazards in metasedimentary rocks of the Anakeesta ridge in Great Smoky Mountains National Park (GRSM), which often depends on the influence of multiple causing factors or geo-factors such as geological structures, slope, topographic elevation, land use, soil type etc. or a combination of these factors. The main objective of the study was to understand the control of geo-factors in initiating debris-slides using different knowledge and data-driven methods in GIS platform. The study was performed in three steps: (1) Evaluation of geometrical relationship between geological discontinuity and topographic orientation in initiation of …

Modeling Extreme Heat Events Using Global Reanalysis Data: An Assessment Of Current Climate Data And The Need For Improved Weather Station Data In Tennessee, John Reasons

Electronic Theses and Dissertations

Wet Bulb Globe Temperature (WBGT) is used to assess categorical heat stress risk factors for individuals working in outdoor environments and to provide guidelines for work/rest ratios and water intake. The variables required to compute WBGT are used by meteorologists for many purposes and are available through the Copernicus Program which was implemented by European Centre for Medium-Range Weather Forecasts (ECMWF) to provide users access to ECMWF Re-Analysis (ERA) historical database. WBGT values for Tennessee during National Weather Service (NWS) issued excessive heat warnings were calculated to determine the need for additional advisories based on WBGT guidelines. Monthly average WBGT …

A Log And Core Analysis Of The Marmaton Group, Granite Wash Fan Delta In The Anadarko Basin, Washita County, Oklahoma, Cole A. Hatchel

Electronic Theses and Dissertations

The Pennsylvanian Marmaton Group Granite Wash located in the southern Anadarko Basin is a fan delta system that consists of stacked arkosic sandstones, conglomerates, and shale, and within Washita County, Oklahoma, are known to be a prolific hydrocarbon producer. The Marmaton Group in Washita County, though, has a variable and largely unestablished stratigraphic framework and sudden changes in lithology throughout the region, both horizontally and laterally. This combined with a lack of core or outcrop data has created confusion in the subsurface, and the Marmaton Group has remained largely unstudied in southern Washita County, OK.

This study examined two sets …

Soil Amelioration And Plant Establishment On Sodium Affected Soils On Galveston Island, Texas, Elaine Harris

Electronic Theses and Dissertations

The storm surge from Hurricane Ike in 2008 inundated much of Galveston Island, Texas, causing lasting below-ground impacts in the form of elevated soil sodium (Na+) concentrations. The Na+ initially killed much of the vegetation on the Island and its persistence in soils and groundwater slowed revegetation with some species. Soil amelioration techniques aimed at reducing soil Na+ concentrations were evaluated on an area affected by the storm surge. The treatments were: constructed raised beds composed of uncontaminated soil, incorporation of organic mulch, gypsum application, and combinations of these treatments. Inputs of Na+ from sea-spray aerosols were also quantified using …

Aerobic Photolysis Mecbl: Structure And Electronic Properties Of Cbl-O-O-Ch3 Intermediate., Aida Bazarganpour

Electronic Theses and Dissertations

The photolysis of methylcobalamin (coenzyme B₁₂) results in homolytic cleavage of the Co-C bond, forming cob(II)alamin and the Co(II)/CH₃ radical pair (RP) which further react with O₂ to form the intermediate (R-O-O-Cbl) that involves in the aerobic photolysis. It has been suggested that the key intermediate (R-O-O-Cbl) involves in aerobic photolysis is the insertion of O₂ between the Co-C bond. Clearly, the exposure of light is needed to induce the activation Co-C bond for generating the Co(II)/CH₃ radical pair (RP). The intermediate (R-O-O-Cbl) undergoes further decomposition to aldehyde as the final product of aerobic …

Designing And Sample Size Calculation In Presence Of Heterogeneity In Biological Studies Involving High-Throughput Data., Sudhir Srivastava

Electronic Theses and Dissertations

The designing and determination of sample size are important for conducting high-throughput biological experiments such as proteomics experiments and RNA-Seq expression studies, thus leading to better understanding of complex mechanisms underlying various biological processes. The variations in the biological data or technical approaches to data collection lead to heterogeneity for the samples under study. We critically worked on the issues of technical and biological heterogeneity. The quantitative measurements based on liquid chromatography (LC) coupled with mass spectrometry (MS) often suffer from the problem of missing values (MVs) and data heterogeneity. We considered a proteomics data set generated from human kidney …

Formally Designing And Implementing Cyber Security Mechanisms In Industrial Control Networks., Mehdi Sabraoui

Electronic Theses and Dissertations

This dissertation describes progress in the state-of-the-art for developing and deploying formally verified cyber security devices in industrial control networks. It begins by detailing the unique struggles that are faced in industrial control networks and why concepts and technologies developed for securing traditional networks might not be appropriate. It uses these unique struggles and examples of contemporary cyber-attacks targeting control systems to argue that progress in securing control systems is best met with formal verification of systems, their specifications, and their security properties. This dissertation then presents a development process and identifies two technologies, TLA+ and seL4, that can be …

Novel Bayesian Methodology In Multivariate Problems., Debamita Kundu

Electronic Theses and Dissertations

This dissertation involves developing novel Bayesian methodology for multivariate problems. In particular, it focuses on two contexts: shrinkage based variable selection in multivariate regression and simultaneous covariance estimation of multiple groups. Both these projects are centered around fully Bayesian inference schemes based on hierarchical modeling to capture context-specific features of the data and the development of computationally efficient estimation algorithm. Variable selection over a potentially large set of covariates in a linear model is quite popular. In the Bayesian context, common prior choices can lead to a posterior expectation of the regression coefficients that is a sparse (or nearly sparse) …

A Study Of Big Field Multivariate Cryptography., Ryann Cartor

Electronic Theses and Dissertations

As the world grapples with the possibility of widespread quantum computing, the cryptosystems of the day need to be up to date. Multivariate Public Key Cryptography is a leading option for security in a post quantum society. One goal of this work is to classify the security of multivariate schemes, especially C*variants. We begin by introducing Multivariate Public Key Cryptography and will then discuss different multivariate schemes and the main types of attacks that have been proven effective against multivariate schemes. Once we have developed an appropriate background, we analyze security of different schemes against particular attacks. Specifically, we …

Algebraic Properties Of Neural Codes., Katie C. Christensen

Electronic Theses and Dissertations

The neural rings and ideals as algebraic tools for analyzing the intrinsic structure of neural codes were introduced by C. Curto, V. Itskov, A. Veliz-Cuba, and N. Youngs in 2013. Since then they have been investigated in several papers, including the 2017 paper by S. G\"unt\"urk\"un, J. Jeffries, and J. Sun, in which the notion of polarization of neural ideals was introduced. We extend their ideas by introducing the polarization of motifs and neural codes, and show that these notions have very nice properties which allow the studying of the intrinsic structure of neural codes of length $n$ via the …

Characterizing Majority Rule On Various Discrete Models Of Consensus., Trevor Leach

Electronic Theses and Dissertations

In any social structure, there is often a need to reach decisions, not only within a group but between groups as well, sometimes even urgently so. Each of the individuals constituting these groups has their own preference for the decision to be made. We will discuss the problem of aggregating individual preferences into a collective preference and under what conditions we are required to select a collective majority. In this dissertation we will look at three models of consensus and show the conditions vary based on the model.

Evaluating Fluid Fluxes From Deep-Sea Seepage Habitats, Leigha E. Peterson

Electronic Theses and Dissertations

The permanently dark deep-sea, located at oceanic water depths greater than 200 m, represents the largest potential habitat space on Earth. The physicochemical conditions of the planet’s largest biome are tightly coupled to the exchange of matter and energy from terrestrial and sea-floor end-members. In fact, global ocean and climate systems are significantly impacted by deep-sea processes. Seafloor vents and seeps appear to act as geologic exchange conduits, returning recycled materials to the hydrosphere to sustain another generation of life. Despite submarine seepage having control on global elemental cycling, it is estimated that less than 1% of the deep-sea has …

Unconventional Oil And Gas Extraction In Ohio: Regulations, Production And Water Quality, Brittany Garman

Electronic Theses and Dissertations

The Utica shale play is the main target for unconventional oil and gas extraction in Ohio. Over 2,000 wells have been drilled since the first in 2011. This rapid expansion has led to concerns over the availability of information and potential environmental impacts. An assessment of readily available data was done through an examination of the ODNR website for oil and gas regulations, permits, spud and completion reports, water usage and waste data, and complaints, as well as brine and de-icer application. Water quality testing of an exceptional warm water tributary in the Captina Creek watershed in Belmont County, Ohio …

Water Quality Assessment Of Deer Lakes County Park Before, During And After Unconventional Shale Gas Drilling, Daniel Robinson

Electronic Theses and Dissertations

Allegheny County, Pennsylvania, signed a lease to allow unconventional natural gas extraction from Marcellus Shale beneath Deer Lakes County Park in 2014. The park has three man-made lakes and four waterways that eventually flow into the Allegheny River. Drilling commenced in early 2016, and there are now five producing wells. The park has an extensive abandoned coal mine network and several abandoned oil and gas wells. Thus, an independent water quality study was undertaken beginning in July 2015. Samples from seven different sites in the park were used to establish a water quality baseline prior to the drilling. Monthly sampling …

The Effects Of Constructed Wetlands On Metal Solubilization And Bioavailability In Passive Mine Remediation, Elizabeth Cochran

Electronic Theses and Dissertations

The legacy of coal mining in Appalachia has left many watersheds impacted by abandoned mine drainage. The drainage degrades streams, groundwater and habitats with acidity and toxic heavy metals. The Lowber Passive Remediation System has been in operation since 2004 to remediate high amounts of dissolved Fe, SO₄, Al, and Mn. The site consists of six settling ponds and an extensive wetlands at the finish. This study investigated the resolubilization of Fe and Mn in the wetlands and the role of bacteria in resolubilization. During three seasons, field measurements of water quality and lab analysis of Fe, Mn, …

Synthesis, Characterization And Crystal Growth Of I2-Ii-Iv-Vi4 And I4-Ii-Iv2-Vi7 Diamond-Like Semiconductors With Potential In Ir-Nlo Applications, Jennifer Glenn

Electronic Theses and Dissertations

In this dissertation, several new and existing diamond-like semiconductors (DLSs) were synthesized and investigated for their potential in infrared nonlinear optical (IR-NLO) applications. In Chapter 2 growth of large single crystals of Li₂MnGeS₄ was carried out using iodine vapor transport and a newly created graphite-tube containment system. This crystallization method produced sizable single crystals on the scale of 2x1x1 mm³, that were used to determine the material’s magnetic properties. Magnetization data indicate that the compound is antiferromagnetic with a Néel temperature of 10 K and an effective magnetic moment of 5.6 /f.u.. The specific heat …

Nontraditional Hydrogen Bonding In Asymmetric Lewis Acid Catalysis, Brandon Vernier

Electronic Theses and Dissertations

In the field of asymmetric induction, there is a shift from the synthesis of reaction

specific chiral auxiliaries towards a broader mechanistic approach. Our approach is to

develop a theory of asymmetric catalyst design from first principles. The Diels-Alder

reaction of 2-methacrolein and 1,3-cyclopentadiene in the presence of 15 mole % lmenthoxy

aluminum dichloride, reported by Koga, achieved the (S)-exo-Diels-Alder

cycloadduct with 72% ee (0% ee Endo for acrolein). The dramatic change from 72% to 0%

ee is a significant fact that has been overlooked in practical organic synthesis.

In the first phase of this work, the conformational landscape of …

Unconventional Gas Extraction In Southwestern Pennsylvania: Complaints, Production, And Water Quality, Dannielle Pratt

Electronic Theses and Dissertations

The dramatic rise in unconventional oil and gas extraction in Pennsylvania has presented a challenge to the Pennsylvania Department of Environmental Protection in managing regulatory required data, and the uniformity of public access via their online databases. This study analyzed over a decade of all the oil and gas complaints and unconventional gas production in Washington County. Of the 1,811 wells drilled between 2004 and 2018, 1,683 are producing, 74 are plugged, 52 regulatory inactive, and 2 abandoned. The PADEP received 10,389 complaints from 2004 to 2018. Only 2,420 of 4,489 water quality complaints were resolved within the legally required …

Microplastics In The Digestive System Of The Atlantic Sharpnose Shark (Rhizoprionodon Terraenovae) In Winyah Bay, Sc, Elise Virginia Pullen

Electronic Theses and Dissertations

The digestive tracts and livers of adult male Atlantic sharpnose sharks (N=16), Rhizoprionodon terraenovae, from Winyah Bay, South Carolina were examined for ingested microplastics. R. terraenovae is a small, locally abundant, coastal mesopredatory elasmobranch belonging to the family Carcharhinidae. Microfibers comprised the largest categories of plastics (94% of the total), and were found in 100% of sharks examined. The number of micro- and other plastics ranged from 34 to 75 per individual and totaled 927. The majority of plastics (40%) were blue in coloration, and 55% were <1 mm in length. Microplastics were observed on both the interior and exterior of the organs examined, and three microfibers were embedded within the stomach lining, an observation not previously reported in marine vertebrates and one which represents a potential pathway for the translocation of ingested microplastics.

Engineering Noble-Metal Nanostructures For Biosensing Applications, Haihang Ye

Electronic Theses and Dissertations

The ability to engineer noble-metal nanostructures (NMNSs) in a controllable manner and to understand the structure-dependent properties greatly boost our knowledge in rational design of biosensing technologies. In particular, as a type of highly efficient peroxidase mimics, NMNSs hold promising potential to break through the bottleneck of conventional enzyme-based in vitro diagnostics. During the time of my Ph.D. study, I have successfully: 1) directed a two-step method involving seed-mediated growth and chemical etching for the synthesis of Ru nanoframes (RuNFs) with face-centered cubic crystal phase and enhanced catalytic activities; 2) demonstrated, for the first time, the inherent peroxidase-like activity of …

Leaning Robust Sequence Features Via Dynamic Temporal Pattern Discovery, Hao Hu

Electronic Theses and Dissertations

As a major type of data, time series possess invaluable latent knowledge for describing the real world and human society. In order to improve the ability of intelligent systems for understanding the world and people, it is critical to design sophisticated machine learning algorithms for extracting robust time series features from such latent knowledge. Motivated by the successful applications of deep learning in computer vision, more and more machine learning researchers put their attentions on the topic of applying deep learning techniques to time series data. However, directly employing current deep models in most time series domains could be problematic. …

Methodological Improvements In The Mrna Profiling Assays For Incorporation Into Dna Casework Workflows, Paris Volk

Electronic Theses and Dissertations

Currently, DNA profiling is the gold standard to identify an individual. However, determining body fluid origin is important in criminal investigations, offering additional information surrounding the circumstances of a crime. However, crime labs can only definitively identify blood and semen and presumptively saliva using techniques that consume time and sample and do not simultaneously identify all forensically relevant body fluids. This causes many crime labs to want to bypass body fluid identification altogether. Therefore, advances into more definitive molecular-based body fluid methods are necessary. One such technique is mRNA profiling because it provides a highly sensitive and specific approach to …

Analysis Of Hydrodynamic And Bathymetric Gradients In Canaveral National Seashore Following Living Shoreline And Oyster Restorations, David Spiering

Electronic Theses and Dissertations

Coastal vulnerability has been gaining recognition as a critical issue, especially with the increasing predictions of sea level rise. Susceptibility to extreme events, eutrophication, and shoreline modification has left many coastal regions in a degraded state. Shoreline protection has traditionally taken the form of seawalls and offshore breakwaters which can be detrimental to both the local ecosystems and adjoining shorelines. The objective of this thesis is to analyze the hydrodynamic and bathymetric variation that occurs within Mosquito Lagoon, Florida following living shoreline and oyster reef restorations. The shoreline sites were sampled using a Before-After-Control-Impact (BACI) design and data were analyzed …

Use Of Anodic Stripping Voltammetry To Study The Size-Selective Electrophoretic Deposition And Aggregation-Dependent Oxidation Of Metal Nanoparticles., Stacy L. Allen

Electronic Theses and Dissertations

This dissertation describes how anodic stripping voltammetry (ASV) was used to study size-controlled electrophoretic deposition (EPD) and the aggregation-dependent oxidation properties of citrate-stabilized Au nanoparticles (NPs). EPD of citrate-coated Au NPs occurs in the presence of hydroquinone (HQ) onto indium-tin-oxide-coated glass electrodes (glass/ITO) at potentials positive of the HQ oxidation potential. HQ oxidation produces protons at the electrode surface, which serve to neutralize the citrate molecules that electrostatically stabilize the Au NPs. Neutralization leads to the loss of stabilization and deposition onto the electrode. EPD in the presence of ferrocyanide, a non-proton-producing molecule, at oxidation potentials resulted in no deposition …