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Articles 1 - 6 of 6

Full-Text Articles in Biomedical Engineering and Bioengineering

Computational Analysis Of The Phylogeny And Thermodynamics Of Glycoside Hydrolases, John Blakely Mertz Jan 2008

Computational Analysis Of The Phylogeny And Thermodynamics Of Glycoside Hydrolases, John Blakely Mertz

Graduate Theses and Dissertations

My research has focused on using computation by means of phylogenetic analysis and molecular mechanics docking studies to further extend knowledge of glycoside hydrolases (GHs). Phylogenetic analysis was used to crystallize the fundamental differences between specific types of cellulases in GH family 6 (GH6). Cellulase enzymes were then examined for functional divergence in order to determine the cause of substrate specificity, finding that very often, active site amino acid residues were highly retained, but surface residues had changed over time, most likely to help interact with other enzymes or larger substrates. Automated docking was able to provide support for the ...


A Study Of The Multi-Environment Conditional Probability-Density Model For Turbulent Non-Premixed Combustion, Sean Thomas Smith Jan 2008

A Study Of The Multi-Environment Conditional Probability-Density Model For Turbulent Non-Premixed Combustion, Sean Thomas Smith

Graduate Theses and Dissertations

The multi-environment conditional probability density function (MECPDF) model is a mathematical description of the turbulent mixing of two streams of chemical reactants along with the complex sequence of chemical reactions that follow. The processes of mixing and chemical reactions can be intricately connected and complex, particularly when the rates of both processes are nearly equal. Furthermore mixing has the potential to completely determine the outcome of the chemical reactions. Mixing will have the strongest effect on chemical reactions when there are multiple reactions with competing pathways that proceed at different rates. As multiple reactions with competing pathways progress, with interaction ...


Steam Reforming Of Bio-Oil: Effect Of Bio-Oil Composition And Stability, Pedro J, Ortiz-Toral Jan 2008

Steam Reforming Of Bio-Oil: Effect Of Bio-Oil Composition And Stability, Pedro J, Ortiz-Toral

Graduate Theses and Dissertations

Hydrogen can be obtained from biomass pyrolysis liquids by catalytic steam reforming. Catalyst deactivation by coking and the formation of carbon deposits are the major known limitations although the specific causes are unidentified. It is proposed that these limitations could be reduced by selectively reforming specific fractions of the bio-oil. The hydrophobic fraction mainly composed of heavy oligomers can be separated by water extraction as a high-value product. In the current work, the particular interest is on efficient hydrogen production from the residual aqueous fractions. There are certain challenges introduced due to the complexity of these mixtures. An improved understanding ...


High-Activity Fuel Cell Catalyst Layers Via Block Copolymer Nanocomposites, Toheeb Bola Alabi Jan 2008

High-Activity Fuel Cell Catalyst Layers Via Block Copolymer Nanocomposites, Toheeb Bola Alabi

Graduate Theses and Dissertations

Current polymer electrolyte membrane fuel cell (PEMFC) catalyst layers are disordered blends of carbon-supported platinum catalyst in an ionomeric matrix. The objective of this research was to design preliminary materials for a self-assembling Pt/SWNT/block copolymer catalyst nanocomposite system for use in a PEMFC catalyst layer. Initial work toward this goal was conducted. Platinum nanoparticles were deposited on SWNTs by way of facile reduction in ethylene glycol, as proven by TGA and TEM. Graft polymerizations of polystyrene from oxidized SWNTs via ATRP reaction and pristine SWNTs via anionic polymerization were successful. The polystyrene brushes displayed improved solubility in organic ...


Development And Testing Of A Combined Catalyst/Sorbent Core-In-Shell Material For The Production Of High Concentration Hydrogen, Karl O. Albrecht Jan 2008

Development And Testing Of A Combined Catalyst/Sorbent Core-In-Shell Material For The Production Of High Concentration Hydrogen, Karl O. Albrecht

Graduate Theses and Dissertations

A combined catalyst and sorbent for the production of hydrogen from CH4 or CO was developed and tested. The combined catalyst and sorbent was a spherical multi-layered material having a CaO-based sorbent core and an outer shell composed mainly of alumina. The CaO sorbent core was employed to absorb CO2, one of the reaction products. The alumina shell protected the friable CaO core and also supported a Ni catalyst. The development of the material focused separately on the development of the core and shell. First, since the CO2 absorption capacity of CaO-based sorbents diminishes as they are ...


Luminescent Water-Soluble Quantum Dots: Improved Stability Through Surface Functionalization, Manuela Aseye Ayele Ayee Jan 2008

Luminescent Water-Soluble Quantum Dots: Improved Stability Through Surface Functionalization, Manuela Aseye Ayele Ayee

Graduate Theses and Dissertations

Colloidally prepared semiconductor nanocrystal quantum dots (QDs) are inherently incompatible with biological systems because of the native hydrophobic molecules that coat their surfaces. Post-synthetic techniques such as ligand exchange and encapsulation are therefore employed to make them soluble in aqueous media while preserving their valuable properties such as bright photoluminescence and stability. Small hydrophilic organic molecules like dihydrolipoic acid and tris(hydroxypropyl)phosphine are used to displace the hydrophobic surface ligands, and derivatization by carbodiimide bioconjugation can enhance pH stability. Several QD encapsulation methods in polymer shells are covered, with the most promising one involving the use of a four-stream ...