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The Influence Of Ion-Ion Correlations On Conductivity In Concentrated Ionic Systems, Md Dipu Ahmed

Masters Theses

This study delves into the fascinating realm of concentrated ionic systems, such as ionic liquids, superionic materials, organic ionic plastic crystals, and polyelectrolytes, which hold immense potential for energy storage applications. The focus is on understanding the intricate role of ionic correlations in shaping their ionic conductivity behavior. These correlations can either boost or impede conductivity, yet their underlying mechanisms remain elusive. Through extensive investigation of various materials, including ionic liquids with differing anionic masses, pure organic ionic plastic crystals, and doped systems, this research employs advanced techniques like dielectric spectroscopy and innovative momentum conservation models to quantify these correlations. …

Synthesis Of Block Copolymer Additives For Examining Phase Morphology And Improving Mechanical Properties Of Thermoplastics Elastomers., Bishal Upadhyay

Masters Theses

Polystyrene-block-poly(1,4-butaidene)-block-polystyrene (PS-PB-PS) triblock copolymers are one of the most widely studied thermoplastic elastomers (TPEs) due to their ease of synthesis, non-polar nature, and commercial applicability. Like many block copolymers, incompatibility between PS and PB causes these TPEs to undergo microphase segregation. Many studies have examined the mechanical properties of blends of TPEs and PS homopolymer additives. However, there have been few studies focused on understanding the morphology and mechanical properties of blends of TPEs and copolymer additives with different architectures. Herein, I describe the synthesis of linear and graft copolymer additives based on the random copolymers poly(methyl methacrylate-random-cyclohexyl methacrylate) (PrC). …

Expression And Purification Of Polyketide Synthase Domains To Investigate Protein-Protein Interactions In Polyketide Biosynthetic Pathways, Mujeeb Adeyinka Wakeel

Masters Theses

Polyketide synthases (PKSs) are multienzyme proteins catalyzing the production of the polyketide class of natural products with vast structural diversity. Type II PKSs catalyze polyketide biosynthesis using discrete (standalone) enzymes (domains), while type I PKSs use covalently linked enzymes arranged in a module to catalyze polyketide production. It is hypothesized that type II PKSs are the precursors to type I PKSs, proposing that the genes encoding individual discrete enzymes in type II PKSs fused to give the multienzyme modules of type I PKSs. We reasoned that the intramolecular-like reactions occurring in type I PKS modules might be a driving force …

Redox-Active Polymerization Catalysts And Their Applications, Nicholas M. Shawver

Masters Theses

Traditional catalyst systems are reliable means to produce polymers with well-defined architectures and thermomechanical properties; however, they are often limited by a narrow monomer scope and their ability access few, if any, advanced polymer architectures. To address this limitation, a new class of catalysts have recently emerged that feature redox-active moieties that may access advanced architectures through catalyst electronic modulation that arises from redox events occurring on the ligand scaffold or at the active metal center itself. For example, researchers have explored the ability of redox-active catalysts to impart “on-off” kinetic control during ring-opening polymerizations and their ability to access …

Development And Study Of Small Database For The Activation Of Nitrous Oxide Towards Formation Of Iron(Iv)-Oxo Species, Tobias Barthalomew Robertson

Masters Theses

Nitrous oxide (N₂O) can undergo an oxygen atom transfer (OAT) reaction resulting in inert nitrogen gas (N₂O) while transferring an oxygen atom to a molecular complex or material. This process is of catalytic importance since this OAT reaction can be leveraged to form iron(IV)-oxo sites, which are known to be catalytic intermediates. Here, an investigation of the ligand field effects on primarily iron(II) complexes for the formation of iron(IV)-oxo sites with nitrous oxide as the oxidant is reported. An initial database of sixty-four molecular complexes with ligand environments varying in field strength and coordination geometry was …

Understanding The Polymerization Of Ethyl Cyanoacrylate In The Superglue Fuming Of Latent Prints To Optimize Print Retrieval, Leondra Shawntae Lawson

Masters Theses

The cyanoacrylate fuming method (CFM) is a widespread process used in forensics to make latent prints visible for detection, acquisition, and analysis. CFM is governed by the reaction of ethyl cyanoacrylate (ECA) with biological components in fingerprints, which serve as initiators for this anionic polymerization. CFM is not a well-controlled polymerization and there are different outcomes that may result from lower temperature, one of which fits the generalization of creating more ion-pair initiators. Another effect could be minimizing termination through suppressing side reactions. Alternatively, when paired with humidity, lower temperatures may cause surface condensation, decreasing the quality of the print. …

Impact Of Cover Crop Species Diversity On Soil Nutrient Availability And Crop Productivity, Amanda Kramer

Masters Theses

Cover crops provide multiple environmental benefits that improve both soil and water quality; however, farmers only utilize them on approximately 5% of harvested U.S. cropland. Low adoption rates are attributed to yield impact concerns, seed and planting costs, and lack of advocacy. This study, which began in October 2019, assessed the effects of nitrogen rate and cover crop diversity on weed biomass, soil coverage, in-situ residue decomposition, soil nitrogen and phosphorus availability, and cash crop yield to better understand the costs and benefits of cover crop adoption at two locations in Tennessee (Milan and Spring Hill). Treatments were replicated 4 …

Synthesis And Characterization Of 2,6-Diisopropylphenoxy Tetrapyrazinoporphyrazines As Potential Molecular Qubits, Benjamin Marx

Masters Theses

This thesis reports the synthesis of metal-free and metal-containing phthalocyanine derivatives using methods typical for that class of functional dyes. A mixture of the target compounds prepared here, one paramagnetic and one diamagnetic tetrapyrazinoporphyrazine, will be tested for their potential use in spintronics – the application of spin-active species in molecular electronics. Phthalocyanines and their derivatives are well-known for their ease of preparation and tunability; they have been utilized as sensitizers for photodynamic therapy of cancer and solar cells, as well as in catalysis and chemical sensing. Tetrapyrazinoporphyrazine complexes are compared with the parent phthalocyanine as their chemistry is similar …

Influence Of Physical Variability Of Highly Weathered Sedimentary Rock On Nitrate In Area 3 Of The Enigma Field Research Site At Y-12, Erin Kelly

Masters Theses

Uranium processing and waste storage in unlined waste ponds leached contaminants into the groundwater at Y-12, Oak Ridge, Tennessee, from the 1950s to 1980s. Groundwater wells near the S-3 ponds have had the highest nitrate concentrations of groundwater anywhere in the world (>10,000 mg/L). For reference, the maximum contaminant level for nitrate in drinking water set by the U.S. Environmental Protection Agency is 10 mg/L. Since 2012, the ENIGMA (Ecosystems and Networks Integrated with Genes and Molecular Assemblies) group has been characterizing, monitoring, and conducting field experiments to understand the interactions between contaminants, microbes, and the subsurface. The goals …

Designing Polymer Materials For Improved Additive Manufacturing, Kaizhong Guan

Masters Theses

Currently, two of the most used additive manufacturing methods for polymers are selective laser sintering (SLS) and fused filament fabrication (FFF). Although at high market size, they both have imperfections. The materials for SLS are limited and the objects manufactured by FFF existing anisotropic behavior. Targeting on these drawbacks, this thesis has proposed a novel method to prepare polypropylene (PP) microsphere which is suitable for SLS with low cost and scalable potential; and a novel material with polycarbonate as matrix that has shown a decrease in anisotropy after FFF printing.

The PP microsphere in this thesis was prepared via liquid-liquid …

Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown

Masters Theses

A substantial societal shift towards environmental awareness has focused research efforts on the impacts of pollution on natural landscapes. Improvements to pollutant regulations and technology have resulted in sizeable reductions of atmospheric deposition of anthropogenic acids, especially nitrates and sulfates, which has altered the role of these ions in the environment. As such, understandings of environmental chemistry dynamics have required regular updating.

Through the National Park Service Vital Signs monitoring program, increases in precipitation pH observed in Great Smoky Mountains National Park (GRSM) has been attributed to the reduction of inorganic acid concentrations. Unfortunately, these improvements have not been uniformly …

Application Of Titrations For Verification Of Small Molecule Interaction In Relation To Amidoximated Fibers For Uranium Extraction From Seawater, Kc Michael Mote

Masters Theses

Nuclear energy is a promising substitute for fossil fuels due to possessing low carbon emissions and providing scalable base-load power. However, one major drawback of using nuclear fuel as an energy source is that it needs a steady source of uranium. While the most economical method of obtaining uranium is through conventional terrestrial mining of the ore uranite, mining uranium ores is both harmful to the environment and limited by the terrestrial uranium supply, which is estimated at only 100 more years. However, more than 1000× more uranium is dissolved in seawater than is reasonably inferred and assured in terrestrial …

Utilization Of Raman Spectroscopic Techniques For Forensic Science Applications, Alyssa Rose Daniel

Masters Theses

In the field of forensic science, it is important to have reliable, accurate, and nondestructive testing methods for evidence collection and testing. Current methods, such as gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC), are destructive to evidence and require lengthy sample preparation. Because of its nondestructive nature, specificity, and portability, Raman spectroscopy has been increasingly improving forensic science. The goal of this work is to expand on the growing pool of knowledge of forensics related Raman applications.

One problem that has plagued forensic scientists for years is how to accurately identify the time since death, or post-mortem interval. …

Synthesis Of Well-Defined Binary Mixed Brushes On 20 Nm Silica Nanoparticles And Asymmetrically End- Functionalized Semicrystalline Poly(Ε-Caprolactone)S, Andrew J. Chancellor

Masters Theses

Well-defined polymers and polymer brushes play an important role in the understanding of their behavior under various conditions and in the fabrication of nanostructured functional materials. This Master’s thesis work focuses the synthesis of two well-defined systems: binary mixed homopolymer brushes grafted on 20 nm silica nanoparticles (NPs) for understanding their microphase separation behavior and asymmetrically end-functionalized semicrystalline poly(- caprolactone) polymers for use in the fabrication of multicomponent polymer brushes on flat substrates with various architectures. While theoretical and simulation studies have revealed intriguing morphologies of mixed homopolymer brushes grafted on nanospheres with a size similar to those of grafted …

Synthesis And Biological Evaluation Of Azide- Tagged Biomimetic Probes For Global Labeling Of The Saccharomyces Cerevisiae Glycerolipidome, Matthew R. Johnson

Masters Theses

Lipid metabolism is an extremely complex, interconnected process that, when dysregulated, is strongly linked to cellular disease states including cancer. Study of these metabolic processes is complicated by the characteristic intricacy of these systems; nonetheless, it is achievable through metabolic labeling. Visualization of biosynthesis is an advantage offered by metabolic labeling through the incorporation of fluorescent tags. In this technique, synthetic probes bearing a clickable tag such as azide are fed into live cells where they are directly incorporated using the native enzymatic and cellular processes to metabolically label lipid products. These labeled lipid products are capable of being studied …

Investigating The Effects Of Tethered, Axial Lewis Base Coordination On Rhodium(Ii) Paddlewheel Complexes, William A. Sheffield

Masters Theses

Dirhodium(II) paddlewheel complexes are highly renowned for their use in diazo decomposition to form a metallic-carbenoid species. This species has been used for a diverse range of chemical transformations including cyclopropanation, cycloproprenation, C-H functionalization, and X-H (Si, S, O, N) insertion reactions. Modulation of these catalysts traditionally involve the exchange of bridging ligands which have profound effects on the catalyst’s reactivity, chemo, and enantioselectivity. Recent interest has turned towards to modifying the axial sites present in the complex as an additional means of modulating catalytic activity. These sites normally serve as the active site of the catalyst, but coordination of …

Sustained Release Of Persulfate And Iron(Ii) Ions From Inert Inorganic Materials For Groundwater Remediation, Peter Pham

Masters Theses

Contamination of groundwater, initiated from years of human negligence, continues to persist despite major advancements in water remediation technologies. The generated groundwater plumes can continuously replenish contaminants such as dense nonaqueous phase liquids (DNAPLs) through the aid of slow-moving water. Thus, long-term treatment of this flow system has proven to be problematic. A selection of sophisticated sustained diffusion technologies is needed to help prevent further damage to this prominent freshwater source.

Here, a novel in-situ chemical oxidation (ISCO) method was designed to incorporate persulfate into silica mediums such as zeolite, diatom, and silica flour for the treatment of groundwater contaminants …

The Effect Of Plant Source On Lignin-Based Polyurethanes And The Interdiffusion Dynamics Of Semi-Rigid Polymers, Jason Michael Lang

Masters Theses

The work reported in this thesis increases our understanding of the effect of lignin plant source on the mechanical and morphological properties of lignin-based polyurethanes and the interdiffusion of glassy/liquid bilayer thin films. The interdiffusion of glassy/liquid polymer pairs has received much less attention than liquid/liquid bilayers, leading to conflicting results and unresolved discrepancies. Therefore, the reported study of interdiffusion between polysulfone glassy/liquid polymer layers provides insight into the dynamics of these systems.

This thesis first reports the correlation between the mechanical properties of lignin-based polyurethanes and the lignin plant source. Lignin is a molecule that can be used as …

Development Of Nuclear Underground Engineered Test Surrogates For Technical Nuclear Forensics Exploitation, Robert Boone Gilbreath

Masters Theses

A method for formulation and production of Nuclear UnderGround Engineered Test Surrogates (NUGETS) based on notional improvised nuclear device (IND) detonations in an underground environment analogous to the Nevada National Security Site (NNSS) is presented. Extensive statistical analyses of precursory geochemical and geophysical characteristics are combined with an augmented surrogate debris cooling technique and predictive IND contributions from the ORIGEN Fallout Analysis Tool. Precursory and resultant elemental compositions, cooling curve calculations, and visual comparison of NUGETS to genuine underground debris are reported. Application of NUGETS methodology to future studies in urban, underground post-detonation technical nuclear forensic (TNF) analysis is suggested.

Three Body Interactions Of Rare Gas Solids Calculated Within The Einstein Model, Dan D'Andrea

Masters Theses

Three body interactions can become important in solids at higher pressures and densities as the molecules can come into close contact. At low temperatures, accurate studies of three body interactions in solids require averaging the three-body terms over the molecules' zero point motions. An efficient, but approximate, averaging approach is based on a polynomial approximation of the three-body term. The polynomial approximation can be developed as a function of the symmetry coordinates of a triangle displaced from its average geometry and also as a function of the Cartesian zero point displacements from each atom’s average position. The polynomial approximation approach …

Synthesis And Characterization Of Novel Ligand For Use On Rhodium Paddlewheel Complexes, Gavin J. Rustin

Masters Theses

Dirhodium (II) paddlewheel complexes have proven to be useful catalysts in many transformations including C-H insertions, cyclopropanation, and silane insertion reactions. One deficiency of these catalysts is the inability to modulate the enantioselectivity with reactive diazo compounds. One avenue for potential improvement of paddlewheel complexes is coordinating ligands in the axial site to increase enantioselectivity. The axial site has been occupied by various ligands including Nheterocyclic carbenes, nitrogen compounds, and phosphorous compounds. This work examines compounds that can be used as ligands on dirhodium complexes that have a pendant chain containing a dibenzyl phosphite and dibenzyl phosphate, both of which …

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …

Incorporating Carbon Nanotubes Into Carbon Fiber Via Surface Modification, Robert Benjamin Ripy

Masters Theses

Ever more advanced materials need to be designed to further the exploration of avenues of science and engineering. Metals and traditional composites are not meeting the needs of today’s stringent demands for lightweight and strong materials. There is a need for advanced materials that are lighter and stronger to replace conventional materials; carbon fiber composites became the obvious choice because of their outstanding mechanical properties. Polyacrylonitrile (PAN) based carbon fiber has reached its apex in terms of its strength to weight ratio. Carbon nanotubes (CNTs) offer a lightweight and potentially stronger alternative to PAN based fibers. However, it is difficult …

Developing Synthetic Methods To Prepare Discrete Metal-Organic Nanotubes, Derek L. Mull

Masters Theses

Metal-organic nanotubes (MONTs) are an emerging class of discrete materials that are the 1D variant of metal-organic frameworks (MOFs). MONTs have potential to become an alternative 1D material to carbon nanotubes, metal oxide nanotubes, and boron nitride nanotubes because they possess an organic ligand that can be functionalized and tuned for specific applications. Despite this potential, only a handful of structures have been reported and only two examples of discrete MONTs exist in the literature. It is thus imperative to develop general methods to prepare and characterize discrete MONTs to bring them to the forefront of the scientific literature.

Efforts …

Magnetron Sputtering And Corrosion Of Ti-Al-C And Cr-Al-C Coatings For Zr-Alloy Nuclear Fuel Cladding, Devin Alan Roberts

Masters Theses

The disaster at the Fukushima Daiichi Nuclear Power Plant in March 2011 bought renewed focus to the issue of corrosion in nuclear fuel cladding applications. This thesis reports on the background behind these issues, the investigation strategy, and the analysis of experiments focused on mitigating oxidation of Zr-alloy fuel cladding. This thesis seeks to develop magnetron sputtered Ti-Al-C and Cr-Al-C coatings for Zr-alloy substrates and characterize the as-deposited and corroded samples.

Ti-Al-C and Cr-Al-C coatings were deposited onto ZIRLO, Si, and Al₂O₃ [Aluminum Oxide] substrates under various sputtering conditions. A combinatorial sputtering method was employed to refine …

Cd Transport In Eutectic Licl-Kcl And Contamination Of Zr Metal And Thermal Dehydration Of Bulk Licl-Kcl, Nicholas Azoy Earle

Masters Theses

Researchers at Idaho National Labs have noted unexpectedly high Cd content in empty cladding hulls after processing in the Mark-IV ER. It has been theorized that Cd metal is transporting from the LCC pool through the eutectic LiCl-KCl salt bath to the anode baskets containing the empty hull where it is retained as a Zr-Cd intermetallic. This study sought to replicate the Cd contamination in a dry Ar glovebox using small-scale analogue of the Mark-IV ER salt-Cd metal system.

Anhydrous eutectic LiCl-KCl was an essential regent in this research and experiments were conducted to investigate the feasibility of dehydrating nominally …

Optical Sensors For The Analysis Of Alcohols In Fuels, Kendhl Kate Witt

Masters Theses

This thesis reports the development of optical sensors to analyze alcohols in fuel samples. One optical sensor enables the analysis of phenol in aviation fuels and cellulosic biofuels. It is critical to monitor the concentration of phenols in fuels because they increase the presence of solid oxidative deposits and lower the thermal stability of fuels. Preliminary studies of another optical sensor have been conducted to detect ethanol in E10 gasoline samples. Gasoline containing ethanol is widely available and used, but the exact percentage of ethanol is not specified and varies between samples and regions. Higher concentrations of ethanol in gasoline …

Siloxane And Silane-Functionalized Polynorbornenes As Membranes For Passive Carbon Dioxide Separation, Eunice Koheun Hong

Masters Theses

In 2012, carbon dioxide (CO₂) [carbon dioxide] accounted for approximately 82% [percent] of all U.S greenhouse gas emissions.¹ These excessive CO2 levels have been attributed to climate changes that have a range of negative effects on human health and welfare.1 In an effort to decrease these emissions, polymeric membranes consisting of silane- and siloxane-functionalized norbornene units have been targeted as a potential solution for the passive separation of CO2 from other non-greenhouse gases. These substituted norbornene-based polymers were synthesized via vinyl-addition polymerization. Through a series of catalyst trials, commercially available palladium and nickel catalysts were compared along …

Rapid Dissolution For Destructive Assay Of Nuclear Melt Glass, Jonathan Allen Gill

Masters Theses

This study evaluates four methods for dissolving complex glassy debris resulting from nuclear detonations. The samples of interest simulate the glassy debris generated from a nuclear detonation’s fireball coming in contact with solid masses. Each method attempts to achieve dissolution through different approaches involving either acid digestion, alkaline digestion, or molten salt fusion. Two of the four methods were modified to retain all elements of the debris or surrogate debris. This retention is critical to the proportional relationships used in identifying fuel types and designs of nuclear weapons. Analysis is conducted with an inductively coupled time of flight mass spectrometer …

Preparation And Characterization Of Thermodynamically Controlled Polymer Nanocomposites, Jiadi Hou

Masters Theses

The mechanical and physical properties of polymeric materials can be greatly improved by adding nanoscale additives. To mediate the dispersion of nanoparticles in polymers, it is often necessary to modify their surfaces to prevent aggregation. While polymer nanocomposites system consisting of homopolymer-grafted nanoparticles are well understood, copolymer-functionalized nanoparticles are less well understood but provide additional ways to alter dispersion through the use of chemically different comonomers. In this thesis, polystyrene nanocomposites blended with copolymer-grafted nanoparticles were prepared and studied. The particular comonomers used were methyl methacrylate and cyclohexyl methacrylate, which provides miscibility with polystyrene. Polymers with varying comonomer ratios were …