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Study Of Additives Used In A Copper Via Filling Chemistry, Sheik Ansar Usman Ibrahim

Master's Theses and Capstones

An experimental study on the effect of additives used in a copper via-filling chemistry is carried out by electroanalytical techniques. These include potential or current pulse reversal deposition and cyclic voltammetry methods. Suppression of electrodeposition caused by polyethylene glycol (PEG) and by a commercial suppressor was examined. Effect of bis-(3-sulfopropyl)-disulfide (SPS) and a combination with the suppressor was also examined. A model based on free accelerant complex formation was used to design the experiments. Contrast in the chemical environment between the bottom and the surface of the vias was simulated on a rotating disk electrode (RDE) by variation of rotation …

Cellulose Hydrolysis By Immobilized T Reesei Cellulase, Paetrice Jones

Master's Theses and Capstones

In the production of cellulosic ethanol, the pretreatment and enzymatic hydrolysis steps are the most influential in determining final ethanol yield and both steps require lower costs to be economically viable. In this work, the use of an ionic liquid (IL), 1-ethyl-3-methylimidazolium diethyl phosphate (EMIM-DEP), as a pretreatment for cellulose as well as four types of immobilized T. Reesei cellulase are investigated. EMIM-DEP is a low viscosity ionic liquid capable of cellulose dissolution. The addition of 2% (v/v) EMIM-DEP during hydrolysis resulted in an initial reaction rate that was 2.7 times higher than hydrolysis rates using no ionic liquid. The …

Optical Measurements In Gas-Liquid Stirred Tanks, Sean Mueller

All Theses and Dissertations (ETDs)

This dissertation outlines the development of novel, in-situ and relatively inexpensive optical measurement techniques for use in opaque multiphase reactors at elevated temperature: 350 ┬░C) and pressure: 180 bar) environments where conventional measurement techniques either cannot be used or are difficult or expensive to implement. Important parameters: such as gas holdup, specific interfacial area, bubble velocity, bubble chord lengths, liquid level, and phase transition) in opaque, multiphase reactors at industrially relevant conditions are lacking in the literature. A miniaturized 4-point probe is developed and methodology outlined that can simultaneously capture local gas holdup, interfacial area, size, and velocities of bubbles …

Zeolites For Cleaner Processes: Alkylation Of Isobutane And N-Butene, Subramanya Nayak

All Theses and Dissertations (ETDs)

Large pore beta zeolite with straight and zig-zag channels and USY zeolite with super cages have shown potential to replace toxic and hazardous mineral acids as catalysts in alkylation processes. However, due to rapid deactivation of these zeolites, their acceptance in industrial alkylation has been delayed. In this study we seek a deeper understanding of the kinetics, transport, and sorption of organic molecules used in alkylation processes in nano-porous zeolites. A six lump kinetic model that considers the key reactions for the zeolite catalyzed alkylation process is presented. The influence of different reactions and rate limiting steps on catalyst, and …

Enzymatic Enhancement Of Water Removal In The Dry Grind Corn To Ethanol Process, Ana Beatriz Thomas

All Theses and Dissertations (ETDs)

The removal of water from coproducts in the fuel ethanol process requires a significant energy input. The drying of the coproducts is responsible for as much as 32% of the total utilities cost of the process. In this study, improvements in the energy and water balances of the corn to ethanol process and a decrease in ethanol production costs were achieved. Significant reductions in water-binding capacity of whole stillage were found for two, commercially available, cell wall degrading enzymes, GC220 and MGC. The addition of a protease, GC106, during fermentation was found to significantly enhance ethanol production rates as well …

Oxygen-Enhanced Combustion: Theory And Applications, Scott Skeen

All Theses and Dissertations (ETDs)

In the broadest sense, oxygen-enhanced combustion: OEC) refers to the use of oxygen to improve combustion and/or process characteristics. When a stream of oxygen is available, a wide range of flame configurations is possible. This work considers two specific configurations of OEC and is divided into two parts. In Part I, fundamental experimental and numerical flame studies explore the combustion of gaseous fuel/inert mixtures in oxygen-enriched air or pure oxygen under well-defined conditions. Part II targets a more practical application by considering the combustion of solid fuels in a variety of oxygen/carbon dioxide mixing scenarios. For gaseous non-premixed flames, combining …

Metal Oxide Semiconductors For Solar Energy Harvesting, Elijah Thimsen

All Theses and Dissertations (ETDs)

The correlation between energy consumption and human development illustrates the importance of this societal resource. We will consume more energy in the future. In light of issues with the status quo, such as climate change, long-term supply and security, solar energy is an attractive source. It is plentiful, virtually inexhaustible, and can provide more than enough energy to power society. However, the issue with producing electricity and fuels from solar energy is that it is expensive, primarily from the materials: silicon) used in building the cells. Metal oxide semiconductors are an attractive class of materials that are extremely low cost …

Getting To The Point: Bridging The Gap Between Simple And Complex Catalytic Systems Using Temporal Analysis Of Products (Tap), Xiaolin Zheng

All Theses and Dissertations (ETDs)

One of the key issues in the field of catalysis is to relate the catalyst structure/composition to its activity/selectivity. One way to understand this relationship is to understand the individual role each catalyst component plays in the chemical reaction. Industrial catalysts can be extremely complex in structure and to understand their reaction kinetics, researchers often study simpler surfaces such as single crystals using surface science techniques. This introduces a well-known problem in the field of catalysis commonly referred to as the "pressure and materials gap." Typically, industrial catalyst research is performed under process conditions, which means operating pressures of one …

Mathematical And Experimental Analysis Of The Steady States In A Simple Microvascular Network System, Ekta Suman

Master's Theses and Capstones

In this paper, a three node network topology with one inlet and two outlets is studied for the existence of the steady state solutions. Both mathematical stimulation and in-vitro experimental methods are studied. The solution for the steady state is found numerically using MATLAB software. The experimental data are studied to verify the stimulation results.

In-vitro experiments are performed on two different diameter (35 micrometers and 50 micrometers) dimension microchannel devices using red blood cells flow. Closing material balance on the feed hematocrit is successfully attained. The results follow the trend of the results obtained from the numerical stimulation. However, …

Effect Of Organic Solvents And Cosolvents On Lipase-Catalyzed Transesterification Of Canola Oil, Boyi Fu

Master's Theses and Capstones

In this thesis, the effect of organic solvents and cosolvents on enzymatic transesterification of canola oil by Candida antarctica lipase was investigated. Twenty-eight organic solvents were assessed and hydrophobic iso-octane was found to be the ideal solvent. Relatively high product yields were also obtained with several hydrophilic solvents possessing high miscibility with methanol. Various solvent-cosolvent mixtures were established to enhance both enzyme activity and mass transfer of substrates. Each mixture comprised a hydrophobic solvent and a hydrophilic cosolvent. At low cosolvent concentrations, biodiesel yield may be enhanced due to improvement in the dispersion of methanol in the cosolvent media. However, …

Enzymatic Reactions In Microdevices, Michael O'Connor

Master's Theses and Capstones

Enzyme reactions conducted in microdevices for diagnostic applications minimize the enzyme usage. In this research, polydimethylsiloxane microdevices were fabricated and used to study the well studied hydrogen peroxide decomposition reaction using bovine liver catalase. Soft lithography techniques were developed to fabricate custom-made microdevices in-house. High resolution photomasks and oxygen plasma treatment followed by baking for 2--3 hours yielded microdevices with vertical walls that did not leak easily. Flow experiments were conducted with free enzyme, enzyme immobilized on microdevice walls, and carrier-free enzyme aggregates. For free enzyme and carrier-free enzyme aggregate reactions, the average reaction rate showed a maxima at ∼80 …