Digital Commons Network^™

Carbon Cycling And Critical Zone Dynamics In An Urbanized Karst Groundwater System, Amy Hourigan

Masters Theses & Specialist Projects

Increasing atmospheric CO₂ concentrations are correlated to rising global temperatures. Investigating the cumulative global carbon cycling processes is important to understand and quantify the global carbon cycle. By investigating basic geochemical parameters, EpCO₂, DIC, and δ¹³C_DIC, at four sites along Lost River Cave (LRC), in Bowling Green, Kentucky, concentrations, fluxes and sources of C dissolved in groundwater were determined. Urban karst groundwater systems, compared to more natural karst landscapes, typically exhibit widespread impervious, heat-absorbing surfaces, urban heat island effects, and increased anthropogenic groundwater inputs and localized CO₂ emissions. Carbonate hydrogeochemical …

An Integrated Gis & Flood Vulnerability Index Approach To Evaluating Risk & Environmental Equity In Urban Karst Communities, Chloe Cooper

Masters Theses & Specialist Projects

This study examines how the usage of an integrated GIS (Geographic Information Systems), flood vulnerability assessment, and management approaches can aid in hazard response planning in karst groundwater systems, particularly in urban environments. In order to also better understand the impacts of flood events on socially vulnerable groups, this research was focused on historically excluded communities. Additionally, place-based vulnerabilities were primarily assessed based upon three main factors in the vulnerability framework and how these components intersect: social, environmental conditions, and economic. By understanding which areas of the City of Bowling Green, an iconic urban karst area, are most vulnerable and …

Robust Sensor Design For The Novel Reduced Models Of The Mead-Marcus Sandwich Beam Equation, Ahmet Aydin

Masters Theses & Specialist Projects

Novel space-discretized Finite Differences-based model reductions are proposed for the partial differential equations (PDE) model of a multi-layer Mead-Marcus-type beam with (i) hinged-hinged and (ii) clamped-free boundary conditions. The PDE model describes transverse vibrations for a sandwich beam whose alternating outer elastic layers constrain viscoelastic core layers, which allow transverse shear. The major goal of this project is to design a single boundary sensor, placed at the tip of the beam, to control the overall dynamics on the beam.

For (i), it is first shown that the PDE model is exactly observable by the so-called nonharmonic Fourier series approach. However, …

Evaluation Of Silver Nanoparticles Attached To Methylene Blue As An Antimicrobial Agent And Its Cytotoxicity, Somon Hakimov

Masters Theses & Specialist Projects

Antibiotics resistance is considered as one of the greatest public health challenges of our time. In this work, we have synthesized silver nanoparticles (Ag NPs) using pulsed liquid ablation in different medium of growth and later combined with methylene blue (MB) to evaluate its potential as an effective photodynamic therapy agent. Ag NPs were synthesized by pulsed laser ablation technique in Polyvinylpyrrolidone (PVP), citrate, and Polyvinyl alcohol (PVA). The Ag NPs were characterized using transmission electron microscopy (TEM), UV-Visible (UV-Vis), and photoluminescence (PL) spectra. Next, Ag NPs were coupled with MB and used to deactivate the Gram-negative bacteria, Escherichia coli …

Canary: An Automated Approach To Security Scanning And Remediation, David Wiles

Masters Theses & Specialist Projects

Modern software has a smaller attack surface today than in the past. Memory-safe languages, container runtimes, virtual machines, and a mature web stack all contribute to the relative safety of the web and software in general compared to years ago. Despite this, we still see high-profile bugs, hacks, and outages which affect major companies and widely-used technologies. The extensive work that has gone into hardening virtualization, containerization, and commonly used applications such as Nginx still depends on the end-user to configure correctly to prevent a compromised machine.

In this paper, I introduce a tool, which I call Canary, which can …

Towards The Determination Of Estrone And 17Β-Estradiol In Dairy Cattle Waste Using Solid Phase And Stir Bar Sorptive Extractions With Liquid Chromatography-Mass Spectrometry And Gas Chromatography-Mass Spectrometry, Pallavi Ragi

Masters Theses & Specialist Projects

Steroidal hormones are naturally produced as a part of many physiological processes and are excreted in the urine and feces of animals and humans. Farm animals in concentrated animal feeding operations (CAFOs) are routinely implanted with synthetic and natural hormones to enhance growth and production, contributing significantly to environmental steroid hormone contamination. Every year around 49 tons of estrogens are generated by livestock waste in the United States alone. Due to rainfall and runoff, these steroid hormones reach the environment when animal waste is applied as manure. Studies show that estrogens and other steroidal hormones present in the surface waters …

Real-Time Monitoring Of Paraquat Photodegradation Using Colloidal Gold Surface Enhanced Raman Spectroscopy, Nathan Wilson

Masters Theses & Specialist Projects

Monitoring chemical reactions in aqueous solution is a challenge because most instrumental techniques either are not suited for the rapid timescales, are not sensitive enough to detect products at low concentrations, or do not have sufficient structure-to-spectrum relationships. Raman spectroscopy is a promising method to monitor reactions, as it is fast, dependent on chemical structure, and has little interference from water. However, Raman scattering is generally very weak. Surface-enhanced Raman spectroscopy (SERS) improves the signal strength of Raman spectroscopy by using a metal surface plasmon, or oscillation of the surface’s electrons, to allow for highly selective and sensitive detection and …

Generation & Kinetic Studies Of Porphyrin Chromium-Oxo Intermediates, Iyanu Olumide Ojo

Masters Theses & Specialist Projects

Recent emerging applications of chromium porphyrin complexes are generating increasing interest in oxidation chemistry and catalysis. Its recent application as metal-organic frames in spintronic devices supports the rich electronic system of chromium metal. Through the past decades, first-row transition metalloporphyrins have served as biomimetic oxidation catalysts and models of cytochrome P450 enzymes. However, the oxygen atom transfer mechanism of chromium porphyrin complexes, most especially in sulfide oxidation reactions, has been scarcely investigated.

In this study, high-valent chromium-oxo porphyrin species, namely Cr^IV-oxo and Cr^V-oxo species, with electron-donating tetramesitylporphyrin(TMP) ligand were successfully generated and characterized with UV-vis, ESI-MS, …

Factors Influencing Tree Growth In A Bottomland Hardwood Along The Green River In Kentucky, Caleb Miller

Masters Theses & Specialist Projects

In bottomland hardwood forests, large fluctuations in moisture availability can lead to stress from both flooded and drought conditions. These forests can have a complex species composition with different water use and drought strategies. The bottomlands in which these species co-occur can have a complex spatial distribution of alluvial sediments due to the meandering and migration of river or stream channels, which may impact the hydrology, nutrient dynamics, and productivity. At Western Kentucky University's Green River Preserve, approximately 9 ha of bottomland hardwood forest were planted in 2006. Although these hardwoods have received equal amounts of sunlight, rainfall, and wind, …

Liquid Chromatography With Tandem Mass Spectrometry Method Development For The Determination Of Β–Defensins In Bovine Milk, Symone T. Whalin

Masters Theses & Specialist Projects

Bovine mastitis, caused by a wide array of pathogens, results in a substantial economic loss for the dairy cattle livestock industry. β-defensins are a part of the bovine’s innate immune system and act as the first line of defense against mastitis. Only foundational research has been done on β-defensins’ ability to treat and prevent mastitis. There have been no analytical methods reported in the literature for analyzing β-defensins in bovine milk. This research aims to create an analytical approach to determine β-defensins in bovine milk. It is challenging to determine an analyte in a complex sample matrix, and milk is …

Towards Semiconductor Nanorods With Nickel/Iron Cocatalyst., Kehinde Ayorinde

Masters Theses & Specialist Projects

The adverse effects associated with the utilization of fossil fuels has led to the need to provide an alternative cleaner energy. Photocatalytic hydrogen evolution reaction via water splitting provides a renewable pathway to generating energy. Our photocatalyst system includes a semiconductor component (CdSe/CdS core/shell nanorods) to capture light and an attached metal (cocatalyst) for the hydrogen evolution reaction. Platinum is an effective metal catalyst for this reaction due to strong proton binding energy that easily facilitates the reduction of water to produce hydrogen gas. However, due to the high cost of platinum, there is a need to find a less …

Semantic Completeness Of Intuitionistic Predicate Logic In A Fully Constructive Meta-Theory, Ian Ray

Masters Theses & Specialist Projects

A constructive proof of the semantic completeness of intuitionistic predicate logic is explored using set-generated complete Heyting Algebra. We work in a constructive set theory that avoids impredicative axioms; for this reason the result is not only intuitionistic but fully constructive. We provide background that makes the thesis accessible to the uninitiated.

A Monte Carlo Analysis Of Seven Dichotomous Variable Confidence Interval Equations, Morgan Juanita Dubose

Masters Theses & Specialist Projects

Department of Psychological Sciences Western Kentucky University There are two options to estimate a range of likely values for the population mean of a continuous variable: one for when the population standard deviation is known and another for when the population standard deviation is unknown. There are seven proposed equations to calculate the confidence interval for the population mean of a dichotomous variable: normal approximation interval, Wilson interval, Jeffreys interval, Clopper-Pearson, Agresti-Coull, arcsine transformation, and logit transformation. In this study, I compared the percent effectiveness of each equation using a Monte Carlo analysis and the interval range over a range …

Reinforcement Learning With Deep Q-Networks, Caleb Cassady

Masters Theses & Specialist Projects

In the past decade, machine learning strategies centered on the use of Deep Neural Networks (DNNs) have caught the interest of researchers due to their success in complicated classification and prediction problems. More recently, these DNNs have been applied to reinforcement learning tasks with state of- the-art results using Deep Q-Networks (DQNs) based on the Q-Learning algorithm. However, the DQN training process is different from standard DNNs and poses significant challenges for certain reinforcement learning environments. This paper examines some of these challenges, compares proposed solutions, and offers novel solutions based on previous research. Experiment implementation available at https://github.com/caleb98/dqlearning.

K-Means Clustering Using Gravity Distance, Ajinkya Vishwas Indulkar

Masters Theses & Specialist Projects

Clustering is an important topic in data modeling. K-means Clustering is a well-known partitional clustering algorithm, where a dataset is separated into groups sharing similar properties. Clustering an unbalanced dataset is a challenging problem in data modeling, where some group has a much larger number of data points than others. When a K-means clustering algorithm with Euclidean distance is applied to such data, the algorithm fails to form good clusters. The standard K-means tends to split data into smaller clusters during a clustering process evenly.

We propose a new K-means clustering algorithm to overcome the disadvantage by introducing a different …

Synthetic, Photophysical, And Catalytic Studies Of Light-Harvesting Macrocyclic Complexes, Fox Bratcher

Masters Theses & Specialist Projects

Chromophores are an important class of compounds in Nature and industry, with several hundred thousand tons produced annually as dyes and pigments. Alone, these compounds absorb light unto themselves; however, several of these compounds can be combined to produce a beneficial cascading transfer of energy to a core chromophore.

In this study, photophysical properties of several covalent and axially borondipyrromethene (BODIPY)-conjugated complexes of porphyrin and salphen scaffolds have been evaluated in a series of emission and catalytic studies. In the porphyrin systems, a beneficial excited energy transfer (EET) from the BODIPY moieties to the porphyrin core was observed; however, only …