Physical Sciences and Mathematics Commons^™

Effects Of Warming On Decomposition Of Submerged Plant Litter And Associated Microorganisms In Streamside Channels, Kaity Ackerman

Electronic Theses and Dissertations

Surface air temperatures are predicted to increase in the near future, which will likely affect microbial activity and carbon flow in stream ecosystems. I performed an experiment in streamside channels at Coweeta Hydrological Laboratory, NC to assess responses of litter-associated microorganisms to moderate increases in water temperature (5 levels, ambient to +4°C). The objectives of the experiment were to determine: (1) if there are differences in the magnitude of responses to temperature among various microbial parameters and (2) whether microbial responses to temperature vary among plant litter of different carbon quality. Thus, I measured litter decomposition rate, fungal biomass (ergosterol), …

Polysaccharide And Silver Nanoparticles Based Hydrogels, Porous Materials, And Sensors, Muhammad R. Hossen

Electronic Theses and Dissertations

Cellulose based hydrogels and porous materials are gaining significant attention across a wide range of applications due to the natural abundance, biodegradability and physicochemical tunability of this polysaccharide. Cellulose nanofibrils (CNF) outperform cellulose fibers in terms of physicochemical tunability since CNF possess relatively high surface area. However, superior dispersibility of CNF in aqueous phase makes it challenging for traditional methods to dewater CNF suspensions to fabricate robust hydrogels and porous materials. In this dissertation, a novel scalable capillary based method to dewater CNF suspensions is invented as well as CNF hydrogels and porous materials with a broad range of porosity …

Using Saddlepoint Approximations And Likelihood-Based Methods To Conduct Statistical Inference For The Mean Of The Beta Distribution, Bryn Brakefield

Electronic Theses and Dissertations

The prevalence of conducting statistical inference for the mean of the beta distribution has been rising in various fields of academic research, such as in immunology that analyzes proportions of rare cell population subsets. For our purposes, we will address this statistical inference problem by using likelihood-based applications to hypothesis testing, along with a relatively new statistical method called saddlepoint approximations. Through simulation work, we will compare the performance of these statistical procedures and provide both the statistical and scientific communities with recommendations on best practices.

Uav 6dof Simulation And Kalman Filter For Localizing Radioactive Sources, John G. Goulet

Electronic Theses and Dissertations

Unmanned Aerial Vehicles (UAVs) expand the available mission-space for a wide range of budgets. Using MATLAB, this project has developed a six degree of freedom (6DOF) simulation of UAV flight, an Extended Kalman Filter (EKF), and an algorithm for localizing radioactive sources using low-cost hardware. The EKF uses simulated low-cost instruments in an effort to estimate the UAV state throughout simulated flight.

The 6DOF simulates aerodynamics, physics, and controls throughout the flight and provides outputs for each time step. Additionally, the 6DOF simulation offers the ability to control UAV flight via preset waypoints or in realtime via keyboard input.

Using …

Ontogenetic And Adult Shape Variation In The Endocast Of Tapirus: Implications For T. Polkensis From The Gray Fossil Site, Thomas M. Gaetano

Electronic Theses and Dissertations

Endocranial morphology provides evidence of sensory ecology and sociality of extinct vertebrates. The Earliest Pliocene Gray Fossil Site (GFS) of NE Tennessee features a conspicuous dominance of skeletal elements belonging to the dwarf tapir, Tapirus polkensis. Numerous individuals in one fossil locality often suggests gregarious behavior, but sociality in T. polkensis contradicts behavior documented for extant Tapirus species. I test T. polkensis for variation in sensory and social ecology using computed tomography and 3D digital endocasts from an ontogenetic sequence. I compare the T. polkensis endocasts with extant Tapirus species using Encephalization Quotients (EQs) and 3D geometric morphometrics. Results …

A Tale Of Two Species: Black-Tailed And White-Tailed Prairie Dog Biogeography From The Last Interglacial To 2070, April Dawn Bledsoe

Electronic Theses and Dissertations

Ecological niche models (ENMs) were created for White-tailed and Black-tailed prairie dogs and projected into the Last Interglacial (LI), the Last Glacial Maximum (LGM), and mid-Holocene (mid-H) to discern possible past suitable habitat for both species. Additionally, ENMs were projected into the future year 2070 representative concentration pathways (RCPs) 2.6 and 8.5 to discern how climate change may affect future habitat suitability. Kernel density estimations, minimum convex polygons, and median distribution centers of White-tailed and Black-tailed occurrence records were examined between time-periods to discern the effects of anthropogenic westward expansion on both species’ distributions. Current ENMs were constructed from commonly …

Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson

Electronic Theses and Dissertations

This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most …

Photocatalytic Carbon Dioxide Reduction With Zinc(Ii) Dipyrrin Photosensitizers And Iron Catalyst, Senan Rasheed

Electronic Theses and Dissertations

Much of the energy used in the United States and around the globe is obtained from petroleum, natural gas, and coal. Photocatalytic CO₂ reduction can be used to transform CO₂ to useful fuels and making fossil fuels more renewable. Input of energy is required, and the sun can provide the required energy for this transformation. Photosensitizer, catalyst, and electron donor are required for photocatalytic CO₂ reduction.

Due to lack of earth-abundant sensitizers, zinc dipyrrin complexes were synthesized by previous group members and have been used as photosensitizers in this research. The ground and excited state electrochemical properties …

Trees With Unique Italian Dominating Functions Of Minimum Weight, Alyssa England

Electronic Theses and Dissertations

An Italian dominating function, abbreviated IDF, of $G$ is a function $f \colon V(G) \rightarrow \{0, 1, 2\}$ satisfying the condition that for every vertex $v \in V(G)$ with $f(v)=0$, we have $\sum_{u \in N(v)} f(u) \ge 2$. That is, either $v$ is adjacent to at least one vertex $u$ with $f(u) = 2$, or to at least two vertices $x$ and $y$ with $f(x) = f(y) = 1$. The Italian domination number, denoted $\gamma_I$(G), is the minimum weight of an IDF in $G$. In this thesis, we use operations that join two trees with a single edge in order …

Computational Quantum Study Of Intermediates Formed During The Partial Oxidation Of Melatonin, Oladun Oladiran

Electronic Theses and Dissertations

Melatonin is a neurohormone produced by the pineal gland in the brain. It functions as an antioxidant to scavenge free radicals. Free radicals are reactive species; they often oxidize the cells leading to oxidative stress which may lead to severe health complications. Reaction of melatonin with free radicals is known to be stepwise, as such the stability of the intermediates can be examined. Thus, the possibility of using melatonin as an in vivo spin trap can be determined. Spin traps allow characterization of unstable radical species using electron spin resonance spectroscopy. In this research, ab initio quantum chemistry techniques were …

Changes In Land Use Land Cover (Lulc), Surface Water Quality And Modelling Surface Discharge In Beaver Creek Watershed, Northeast Tennessee And Southwest Virginia, Tosin James

Electronic Theses and Dissertations

Beaver Creek is an impaired streams that is not supporting its designated use for recreation due to Escherichia coli (E.coli), and sediment. To address this problem, this thesis was divided into two studies.

The first study explored changes in Land Use Land Cover (LULC), and its impact on surface water quality. Changes in E.coli load between 1997-2001 and 2014-2018 were analyzed. Also, Landsat data of 2001, and 2018 were examined in Terrset 18.31. Mann-Whitney test only showed a significant reduction in E.coli for one site. Negative correlation was established between E.coli load, and Developed LULC, Forest LULC, and …

An Analysis Of The First Passage To The Origin (Fpo) Distribution, Aradhana Soni

Electronic Theses and Dissertations

What is the probability that in a fair coin toss game (a simple random walk) we go bankrupt in n steps when there is an initial lead of some known or unknown quantity $m? What is the distribution of the number of steps N that it takes for the lead to vanish? This thesis explores some of the features of this first passage to the origin (FPO) distribution. First, we explore the distribution of N when m is known. Next, we compute the maximum likelihood estimators of m for a fixed n and also the posterior distribution of m when …

Investigation Of Multiple Imputation Methods For Categorical Variables, Samantha Miranda

Electronic Theses and Dissertations

We compare different multiple imputation methods for categorical variables using the MICE package in R. We take a complete data set and remove different levels of missingness and evaluate the imputation methods for each level of missingness. Logistic regression imputation and linear discriminant analysis (LDA) are used for binary variables. Multinomial logit imputation and LDA are used for nominal variables while ordered logit imputation and LDA are used for ordinal variables. After imputation, the regression coefficients, percent deviation index (PDI) values, and relative frequency tables were found for each imputed data set for each level of missingness and compared to …

Synthesis And Characterization Of Carbon Monoxide Producers Bipyridine Flavonolate Palladium(Ii) And Platinum(Ii) Complexes: Potential Anti-Cancer Agents, Sarah Whitfield

Electronic Theses and Dissertations

Novel designed metal ligand complexes as prodrugs are useful in the effort to find more effective and selective anti-cancer treatments. Carbon monoxide, CO, is known to induce mitochondrial collapse in cancer cells. Herein is described the synthesis of seven novel bipyridine flavonolate palladium(II) and platinum(II) complexes with the property of releasing carbon monoxide, and their characterization with FTIR, UV-Vis, fluorescence, NMR, and ESI mass spectra. Their ability to release carbon monoxide was investigated through oxygenation reaction under various conditions of temperature and light irradiation. The nitroxygenation reaction of the palladium complexes was also studied with nitrosyl hydride, HNO, generated in …

Applications Of Digital Remote Sensing To Quantify Glacier Change In Glacier And Mount Rainier National Parks, Brianna Clark

Electronic Theses and Dissertations

Digital remote sensing and geographic information systems were employed in performing area and volume calculations on glacial landscapes. Characteristics of glaciers from two geographic regions, the Intermountain Region (between the Rocky Mountain and Cascade Ranges) and the Pacific Northwest, were estimated for the years 1985, 2000, and 2015. Glacier National Park was studied for the Intermountain Region whereas Mount Rainier National Park was representative of the glaciers in the Pacific Northwest. Within the thirty year period of the study, the glaciers in Glacier National Park decreased in area by 27.5 percent while those on Mount Rainier only decreased by 5.7 …

Functional Nanomaterials By Combining Aminooxy Chemistry And Iodine Activation At Momolayer Protected Clusters., Tirtha Raj Sibakoti

Electronic Theses and Dissertations

Aminooxy (-ONH₂) groups are most commonly known for their chemoselective reaction with carbonyl compounds (aldehydes/ketones) under mild reaction conditions. Aminooxy-based click chemistry is a versatile means of ligation as evidenced by broad application in material science, biology, biochemistry, analytical chemistry, and nanoscience. Our work exploits the facile reaction of aminooxy groups presented on the surface of gold (Au) or palladium (Pd) monolayer protected clusters (MPCs) with various aldehydes via oximation reactions, which form the robust oxime ether adducts. The functionalization of hexanethiolate-stabilized Au MPCs with a newly developed trifunctional amine-containing aminooxy alkanethiol ligand by thiol place-exchange affords aminooxylated …

Mesoporous Adsorbents For Perfluorinated Compounds, Bertha Lotsi

Electronic Theses and Dissertations

Effective adsorbents for polyfluorinated compounds (PFCs) were successfully prepared. And they were tested in the adsorption of perfluorooctanoic and perfluorooctanesulfonic acids. Bridged silsesquioxanes containing secondary and tertiary amino groups were synthesized by sol-gel condensation of bis[3-(trimethoxysilyl)propyl]amine and bis[3-(methylamino)propyl]-trimethoxysilane in acidic media with surfactants. Obtained materials are mesoporous with a high BET surface area. They combine high structural stability with a high concentration of surface amino groups serving as adsorption sites. Batch adsorption tests demonstrated their extremely high adsorption capacity on PFCs: in some experiments, it reached up to 88% of the adsorbent weight. Adsorption of PFCs changed the surfaces of …

An Unusual Mastodon Revisited: Providing A Regional Focus For Mammut Americanum (Proboscidea, Mammutidae) In The Southeast, Matthew Inabinett

Electronic Theses and Dissertations

A century ago, two large American mastodon Mammut americanum specimens from coastal South Carolina were mounted for display at Amherst College. Their robust build, broad and pentalophodont third molars, and well-developed mandibular tusks were noted as unusual. Here, these specimens are redescribed; three additional mastodon mandibles from the same region of South Carolina are also described. Though collection information on these specimens is sparse, they appear to span >150 ka in the Middle to Late Pleistocene, and probably include the first report of Mammut from the earliest-Rancholabrean Ten Mile Hill Formation. Some “unusual” features — moderately to extremely broad third …

Characterization Of Surface Karst Using Lidar And Field Traverses, Fort Hood Military Installation, Coryell County, Texas, Heather Jaclyn Dailey

Electronic Theses and Dissertations

The Fort Hood Military Installation is a karst landscape that has been significantly altered for training exercises that include heavy vehicle maneuvers and simulated combat. Traditional karst surveys are often time-consuming and require extensive field analyses to adequately characterize large areas. Bias is given to areas that are most easily accessible and false negatives are common. Previous studies conducted in the eastern and western portion of the base have understated the abundance and spatial distribution of karst, particularly in the western portion.

This study used field traverses and 0.5-meter Light Detection and Ranging (LiDAR) data to characterize surface karst depressions, …

A Novel Mathematical Model Of The Trojan Y-Chromosome Strategy With Optimal Control, Christopher Turner

Electronic Theses and Dissertations

Invasive species are a prevalent problem all over the world. Controlling and eradicating an invasive species is an even more diffcult problem. The Trojan Y Chromosome (TYC) eradication strategy is one control method. This method alters the female to male sex ratio by introducing sex reversed males called supermales. These sex reversed males can only produce male progeny. Mathematical models of this strategy have shown that a population can be driven to extinction with a continuous supply of these sex reversed males. There are many different mathematical models of this strategy, but most have serious flaws, such as negative solutions …

Novel Inference Methods For Generalized Linear Models Using Shrinkage Priors And Data Augmentation., Arinjita Bhattacharyya

Electronic Theses and Dissertations

Generalized linear models have broad applications in biostatistics and sociology. In a regression setup, the main target is to find a relevant set of predictors out of a large collection of covariates. Sparsity is the assumption that only a few of these covariates in a regression setup have a meaningful correlation with an outcome variate of interest. Sparsity is incorporated by regularizing the irrelevant slopes towards zero without changing the relevant predictors and keeping the resulting inferences intact. Frequentist variable selection and sparsity are addressed by popular techniques like Lasso, Elastic Net. Bayesian penalized regression can tackle the curse of …

Novel Bayesian Methodology For The Analysis Of Single-Cell Rna Sequencing Data., Michael Sekula

Electronic Theses and Dissertations

With single-cell RNA sequencing (scRNA-seq) technology, researchers are able to gain a better understanding of health and disease through the analysis of gene expression data at the cellular-level; however, scRNA-seq data tend to have high proportions of zero values, increased cell-to-cell variability, and overdispersion due to abnormally large expression counts, which create new statistical problems that need to be addressed. This dissertation includes three research projects that propose Bayesian methodology suitable for scRNA-seq analysis. In the first project, a hurdle model for identifying differentially expressed genes across cell types in scRNA-seq data is presented. This model incorporates a correlated random …

Electrochemical Reduction Of Carbon Dioxide And Carbon Monoxide For The Production Of Green Fuels And Chemicals., Jacob M. Strain

Electronic Theses and Dissertations

It has become apparent that closing the carbon cycle on this planet in order to mitigate disastrous consequences of runaway global warming has become one of the most pressing issues of our civilization. One of the ways we need to accomplish this goal is by finding news methods to generate fuels that will be carbon neutral. Renewable fuels and green chemicals will be a major component of closing the carbon cycle and restoring our planet’s ecosystem into a sense of balance. A method that can help achieve this goal is the reduction of CO₂. If CO₂ can …

Assessing Predictors Of Harmful Algal Blooms In The Western Lake Erie Basin., Katherine M. Weigle

Electronic Theses and Dissertations

Harmful algal blooms (HABs) have been a recurring issue in the Western Lake Erie Basin for more than a decade, despite policies implemented to improve the water quality of the Great Lakes. HABs describe algae that can be harmful to both ecosystem function and human health. The Western Lake Erie Basin, in particular, experiences Microcystis aeruginosa blooms in the summer months due to a multitude of factors leading to increased phosphorus and nitrogen loads in the contributing watersheds. In this study, lake water surface temperature, land cover, river discharge, and precipitation were examined as potential triggers for the occurrence and …

Computational Modeling Of Photolysis And Catalysis Reactions In Vitamin B12-Dependent Enzymes., Abdullah Al Mamun

Electronic Theses and Dissertations

Vitamin B₁₂ is a complex organometallic molecule, the derivatives of which such as adenosylcobalamin (AdoCbl) and methylcobalamin (CH₃Cbl) act as a cofactor in numerous enzymatic reactions. These two biologically active cofactors contain a unique organometallic Co-C σ bond. Important feature of this Co-C bond is that it can be activated by both thermally and photolytically inside the enzymatic environment as well as in the solution. In the case of enzymatic reactions where AdoCbl molecule act as a cofactor, the cleavage of the Co-C bond constitutes the key catalytic step. The most intriguing features of this cleavage is …

Analyzing The Effects Of Of Seasonal Land Cover And Precipitation On The Sediment Delivery Ratio Of An Agriculture Dominated Watershed., Jonah Liebman

Electronic Theses and Dissertations

Soil erosion is of escalating importance as increasing population and climate change have put increasing pressures on agricultural food production. Vegetation and precipitation are two factors that control the amount of soil erosion extant within a region. Sediment delivery ratios (SDRs) assess the ratio of soil eroded from a watershed system that is permanently removed from the system through stream sediment discharge. Using 1) river discharge and sediment concentration data and 2) the Revised Universal Soil Loss Equation (RUSLE), this thesis analyzes fluctuations in monthly SDRs for an average hydroclimatological crop-harvest season for the Senachwine Creek watershed, IL. Through calculating …

Stacking The Odds For Better Gpr: An Antenna Comparison, Montana Kruske

Electronic Theses and Dissertations

Ground penetrating radar (GPR) is limited by depth penetration and signal-to-noise ratio (SNR), impacting the ability to resolve subsurface features. Stacking, a process of averaging multiple scans in the same location, improves SNR. Digital antennas are capable of stacking at much higher rates than analog antennas. Four sites were examined using a GSSI SIR-4000 GPR unit with a 400 MHz analog antenna and a 350 MHz digital “hyperstacking” (350 HS) antenna. Sites represent various soil conditions, with known features. Data were compared qualitatively and quantitatively for differences in antenna outputs. Visual inspection of radargrams indicate a reduction in noise in …

Knot Flow Classification And Its Applications In Vehicular Ad-Hoc Networks (Vanet), David Schmidt

Electronic Theses and Dissertations

Intrusion detection systems (IDSs) play a crucial role in the identification and mitigation for attacks on host systems. Of these systems, vehicular ad hoc networks (VANETs) are difficult to protect due to the dynamic nature of their clients and their necessity for constant interaction with their respective cyber-physical systems. Currently, there is a need for a VANET-specific IDS that meets this criterion. To this end, a spline-based intrusion detection system has been pioneered as a solution. By combining clustering with spline-based general linear model classification, this knot flow classification method (KFC) allows for robust intrusion detection to occur. Due its …

Storm Sampling To Assess Inclement Weather Impacts On Water Quality In A Karst Watershed: Sinking Creek, Watauga Watershed, East Tennessee, Porcha Mccurdy

Electronic Theses and Dissertations

Escherichia coli changes in Sinking Creek, an impaired water body in the Watauga watershed of northeast Tennessee, were assessed during storm events using water samples collected with ISCO automated samplers during eight storms at two locations. Turbidity and electrical conductivity (EC) data loggers were deployed in the creek, and dissolved oxygen (DO) was measured in situ to test the stream’s water quality and reaction to inclement weather. Cotton fabric was deployed at both locations and sent to an external lab to test for the presence of Optical Brighteners (OB), which are indicators of residential wastewater. E. coli and turbidity at …

Immobilization Of Phosphotungstic Acid On Silica Surface For Catalytic Alkylation Of Aromatic Compounds, Anastasia Kuvayskaya

Electronic Theses and Dissertations

Superacidic mesoporous materials containing covalently embedded PTA were synthesized by sol-gel method. Tetraethyl orthosilicate (TEOS) and phosphotungstic acid (PTA) were used as precursors in the synthesis, ionic and nonionic surfactants were used as pore-forming agents, the reaction proceeded in acidic media. TEM images revealed mesoporous structure with embedded PTA clusters. FT-IR spectra of obtained materials contained characteristic bands of PTA at 957 cm-1. Synthesized catalysts had high BET surface area and high concentration of acidic sites. Alkylation of 1,3,5-trimethylbenzene by 1-decene demonstrated high catalytic activity. The catalyst obtained with Pluronic P123 as a template was the most effective and resulted …