Digital Commons Network^™

Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera

Doctoral Dissertations

In this work, a systematic computational study directed toward developing a molecular-level understanding of gas adsorption and diffusion characteristics in nano-porous materials is presented. Two different types of porous adsorbents were studied, one crystalline and the other amorphous. Physisorption and diffusion of hydrogen in ten iso-reticular metal-organic frameworks (IRMOFs) were investigated. A set of nine adsorbents taken from a class of novel, amorphous nano-porous materials composed of spherosilicate building blocks and isolated metal sites was also studied, with attention paid to the adsorptive and diffusive behavior of hydrogen, methane, carbon dioxide and their binary mixtures. Both classes of materials were …

Membrane And Performance Study In Polymer Electrolyte Membrane Fuel Cells And Hydrogen Bromine Redox Flow Batteries, Yujia Bai

Doctoral Dissertations

This dissertation represents the consideration of the problems of polymer electrolyte membrane fuel cells (PEMFC) and hydrogen-bromine redox flow batteries (RFB). Due to the importance of water management in PEMFCs, all the experiments were strictly controlled at different water hydration conditions. Water uptake and densities were measured for Nafion^® and a series of 3M ionomer membranes. The thermodynamics of water and polymer was analyzed based on water uptake experiment and calorimetry. Furthermore, partial molar volumes (PMV) of water/membrane system was defined for the first time and used to analyze the interaction between water and polymers. Three states of water …

A Study About Aqueous Reversible Air Electrode- Catalyst, Electrolyte And Structure, Ming Qi

Doctoral Dissertations

Developing a better high energy density rechargeable battery has becoming critically important for several industries. For building such kind of battery, reversible air electrode has been widely accepted as one of the key components. One of the major challenges for reversible air electrode is finding a good bifunctional catalyst to greatly reduce the recharge overpotential and increase the system efficiency. To achieve this goal, a new air battery chemistry based on cobalt salen modified Au catalyst is proposed in this dissertation as a very promising solution. The unique catalytic activity of this catalyst is found to be a two electron …

Development Of A Monitoring Framework For The Detection Of Diversion Of Intermediate Products In A Generic Natural Uranium Conversion Plant, Jennifer L. Ladd-Lively

Doctoral Dissertations

The objective of this work is the development of an on-line monitoring and data analysis framework that could detect the diversion of intermediate products such as uranium dioxide, uranium tetrafluoride, and uranium hexafluoride in a natural uranium conversion plant (NUCP) using a multivariate statistical approach. This was an initial effort to determine the feasibility of this approach for safeguards applications. This study was limited to a 100 metric ton of uranium (MTU) per year NUCP using the wet solvent extraction method for the purification of uranium ore concentrate. A key component in the multivariate statistical methodology was the Principal Component …

Structure And Energetics Of Nanoparticles And Ionomer Films In Fuel Cell Catalyst Layers, Qianping He

Doctoral Dissertations

Improving the durability and utilization efficiency of the platinum-on-carbon (Pt/C) catalyst is of vital importance to the commercialization of the polymer electrolyte membrane fuel cell (PEMFC). This body of work provides molecular level insights to aid the fulfillment of this goal. Chapter 1 describes the use of molecular dynamics (MD) simulation in an effort to understand the Pt/C degradation issue from the nano-adhesion point of view. The roles of catalyst nanoparticle size, shape, Pt/C surface oxidation and the extent of ionomer film hydration are investigated to study their effects on nano-particle adhesion. It is found that the adhesion force strengthens …

A Tale Of Two Protein Switches: Engineering, Characterizing, And Understanding A Novel And A Natural Switch, James Vincent Price

Doctoral Dissertations

Throughout nature, many proteins provide a specific function in response to some input signal (e.g., phosyphorylation, pH, etc.), a process that is oftentimes described as switching a protein “on” or “off.” The advent of protein engineering has allowed for the creation and understanding of chimeric proteins for uses in a number of applications such as therapeutics, biosensors and energy production. Two proteins, hemagglutinin (HA) of fowl plague influenza virus and a chimeric protein comprising a fusion between the LFA-1 I domain and the EF3 and EF4 hands of calmodulin, have been investigated in this dissertation. Both of these proteins undergo …

Characterization Techniques And Electrolyte Separator Performance Investigation For All Vanadium Redox Flow Battery, Zhijiang Tang

Doctoral Dissertations

The all-vanadium redox flow battery (VRFB) is an excellent prospect for large scale energy storage in an electricity grid level application. High battery performance has lately been achieved by using a novel cell configuration with advanced materials. However, more work is still required to better understand the reaction kinetics and transport behaviors in the battery to guide battery system optimization and new battery material development. The first part of my work is the characterization of the battery systems with flow-through or flow-by cell configurations. The configuration difference between two cell structures exhibit significantly different polarization behavior. The battery output can …

The Onset Of Purely Elastic And Thermo-Elastic Instabilities In The Taylor-Couette Flow: Influence Of Gap Ratio And Fluid Thermal Sensitivity, Mohammadreza Ghanbari

Masters Theses

Linear stability analysis of Taylor-Couette flow of dilute polymeric solutions has been performed by using two prototypical constitutive equations for polymeric solutions namely, the Oldroyd-B and the FENE-P models. The hydrodynamic stability characteristics of the flow in presence and absence of thermal effects and in the limit of vanishing fluid inertia have been determined using an eigenvalue analysis. Particular attention has been paid to accurate determination of the instability onset conditions as a function of fluid thermal sensitivity and gap ratio. We observe a reduction in the critical Deborah, Dec for the instability onset as the gap ratio and fluid …

Structure And Morphology Of Sulfonated Polysulfone And Perfluorosulfonic Acid Ionomers, Chen Wang

Doctoral Dissertations

The limitations of conventional perfluorosulfonic acid (PFSA) based membrane materials have provoked the search for alternative materials which can function as the electrolyte in PEM fuel cells operated at higher temperatures (> 100 °C) and without humidification. A novel class of sulfonated poly(phenylene) sulfone (sPSO2) ionomers have shown much higher proton conductivity than typical PFSA membranes at elevated temperatures. In this dissertation, both computational and experimental methods were used to investigate proton transfer, morphological and structural properties of sPSO2 and PFSA ionomers. We have undertaken ab initio electronic structure calculations to understand the primary hydration and the transfer of protons …

A Base Case Design And Capital Cost Analysis Of An All Vanadium Redox-Flow Battery, Mark Alan Moore

Masters Theses

Interest in the development of redox-flow batteries (RFBs) for large-scale grid storage is growing, and considerable investments have been made into the research and development of RFBs over the past few decades. Unfortunately, practical implementation has been hampered by various cost and performance issues typical of an immature state of development. One critical factor for the competitiveness of this technology is the installed cost. The purpose of this work is to develop an evolutionary procedure to be used for the base-case design of a Vanadium Redox-Flow Battery, and to incorporate recent developments in all-vanadium RFB research in order to present …

Filomicelle Functionalization And Stability Studies With Applications For Malaria Treatments, Megan Haoyun Yang

Masters Theses

Malaria is an infectious disease caused by the parasite Plasmodium that is transmitted by mosquitoes. It is estimated that malaria causes 1.1 million deaths per year globally. While anti-malarial drugs have been effective in treating infected individuals, new methodologies are needed. Treatments may benefit from approaches that encapsulate drugs in vehicles allowing for more effective delivery. To this end, the use of targeted drug delivery vehicles called filomicelles to treat malaria is proposed.

Certain amphiphilic diblock copolymers self-assemble into filomicelles (long and stable cylindrical micelles), which are capable of carrying hydrophobic drugs in the bodies of rodents. It is shown …

The Impact Of Selective Solvents On The Structure And Function Evolution In Solvent Annealed Organic Photovoltaics, Sheng Hu

Masters Theses

The role of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) solubility on the evolution of structure and function in solvent annealed organic photovoltaics is quantitatively investigated. ODCB solvent vapor distribution during the solvent uptake process is simulated on a 3-D profile. Determination of solvent uptake in the P3HT/PCBM mixture shows that the evolution of the morphology during solvent annealing (SVA) takes much longer than the diffusion of the solvent vapor into the sample. The evolution of P3HT crystallinity, as well as the growth of PCBM aggregates, in the solvent annealed thin films is observed by Grazing Incidence Wide …

Application Of Synthetic Biology For Increasing Anaerobic Biodiesel Production In Escherichia Coli, Michael Christopher Wierzbicki

Masters Theses

The ever-increasing demand for transportation biofuels requires new and novel approaches to solve the complexities associated with efficient biofuel production. Ethanol, the most common biofuel, has physical limitation associated with difficulty of separations and issues with water contamination and as such is not a long-term transportation fuel solution. (Lou & Singh, 2010; Wheals, Basso, Alves, & Amorim, 1999) Biodiesel is seen as a possible alternative to ethanol due to its hydrophobicity and also has comparable energy density and cetane number to its petroleum derived counterpart. (Kalscheuer, Stölting, & Steinbüchel, 2006) Because of feedstock limitations, biodiesel produced from vegetable oils is …

Studies Of Reaction Processes For Voloxidation Methods, Jared Allen Johnson

Doctoral Dissertations

Various facets of the voloxidation process and processes that have been derived from the voloxidation process have been investigated since its development over four decades ago. Despite the numerous studies performed, gaps remain in understanding of particular fundamental aspects of the reaction processes. In this work, several of these specific aspects of the oxidation processes for standard voloxidation and NO₂ [nitrogen dioxide] voloxidation are studied experimentally and modeled.

In the case of standard voloxidation, the oxidation rates of simulant UO_­2 [uranium dioxide] pressurized water reactor pellets in oxygen-rich environments were studied with an emphasis on the controlling phenomena …

The Impact Of Biodiesel-Based Na On The Durability Of Cu-Zeolite Scr Catalysts And Other Diesel Aftertreatment Devices, Daniel William Brookshear

Doctoral Dissertations

Biodiesel fuel has increased in popularity in recent years as an alternative fuel choice, but there are concerns related to the impact it will have on diesel engines and aftertreatment systems relative to conventional diesel fuel. One major concern is the presence of sodium (Na) in finished biodiesel fuel due to the use of Na-hydroxyl as a liquid-phase catalyst during biodiesel synthesis. The current study focuses on determining the impact of biodiesel-based Na on the performance and materials characterization of diesel aftertreatment devices including lean NOx traps (LNT), diesel oxidation catalysts (DOC), diesel particulate filters (DPF), and Cu-zeolite selective catalytic …

Industrial Robustness: Understanding The Mechanism Of Tolerance For The Populus Hydrolysate Tolerant Strain Of Clostridium Thermocellum, Jessica Leigh Linville

Doctoral Dissertations

An industrially robust microorganism that can efficiently degrade and convert lignocellulosic biomass into ethanol and next-generation fuels is required to economically produce future sustainable liquid transportation fuels. The anaerobic, thermophilic, cellulolytic bacterium Clostridium thermocellum is a candidate microorganism for such conversions but it, like many bacteria, is sensitive to potential toxic inhibitors developed in the hydrolysate produced during biomass processing. Microbial processes leading to tolerance of the inhibitory compounds found in the pretreated biomass hydrolysate are likely complex and involve multiple genes. In this study, a 17.5% v/v Populus hydrolysate tolerant mutant strain of C. thermocellum was developed by directed …

Economic Report On Vanadium Redox Flow Battery With Optimization Of Flow Rate, Kevin Spellman, Kendrick Stiles, Ian Little

Chancellor’s Honors Program Projects

No abstract provided.

Characterization Of Influenza Hemagglutinin Mutants For The Elucidation Of Key Residues’ Effect On Activation, Morgan Baltz

Chancellor’s Honors Program Projects

No abstract provided.

Study Level Design Of A Vanadium Redox Flow Battery, Katie Lutes

Chancellor’s Honors Program Projects

No abstract provided.