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Articles 1 - 5 of 5

Full-Text Articles in Engineering

Fundamental Studies Of Hydrogen Interaction With Supported Metal And Bimetallic Catalysts , Sandeep Bhatia Jan 1993

Fundamental Studies Of Hydrogen Interaction With Supported Metal And Bimetallic Catalysts , Sandeep Bhatia

Retrospective Theses and Dissertations

An in situ [superscript]1H nuclear magnetic resonance (NMR) technique has been employed to study the interaction of hydrogen with silica supported metal and bimetallic catalysts. This technique was applied in the temperature range of 300 to 473 K and at pressures of 10[superscript]-5 to 760 Torr. On ruthenium and rhodium catalysts two distinct adsorbed resonances were detected. We have labelled these resonances as [alpha] and [beta]. The [beta] resonance is associated with a more weakly adsorbed species and was observable only at pressures greater than 100 Torr. Both these resonances represent adsorbed hydrogen interacting with the metal ...


Enhancement Of Polyelectrolyte Precipitation Through The Genetic Fusion Of Charged Polypeptides To Enzymes , Mark Quinn Niederauer Jan 1993

Enhancement Of Polyelectrolyte Precipitation Through The Genetic Fusion Of Charged Polypeptides To Enzymes , Mark Quinn Niederauer

Retrospective Theses and Dissertations

The focus of this work was to investigate the enhancement of polyelectrolyte precipitation through the genetic alteration of the target protein. The dissertation is divided into three primary chapters: a literature review of precipitation techniques which display high selectivity, experimental work including the characterization and precipitation of the fusion enzymes, and modeling of the precipitation process;The literature review of selective precipitation techniques focuses on those techniques for which relatively high purifications can be achieved. The techniques include precipitation with polyelectrolytes, affinity ligands, metal ions, and protein-binding dyes. Topics discussed include the mechanisms of selectivity and precipitation, degrees of purification ...


Electrochemical And Surface Topographic Studies Of Oxide Film Passivation Of Aluminum , Yongsug Tak Jan 1993

Electrochemical And Surface Topographic Studies Of Oxide Film Passivation Of Aluminum , Yongsug Tak

Retrospective Theses and Dissertations

Passivation of corroding surfaces in aluminum etch pits and tunnels was investigated by step reductions and cathodic pulses in applied etching current. Morphology study shows that, in the early stage of passivation, the corroding surface consisted of recessed patches, which are actively dissolving surface, and flat passive area. These active patches are found within the potential range between the potential of zero charge (E[subscript]PZC) and the repassivation potential, and the actively corroding area increases with potential, from zero near E[subscript]PZC to the entire surface at the repassivation potential. A mathematical model describing the progress of passivation ...


Visualizing Thermodynamic Stability And Phase Equilibrium Through Computer Graphics , Daniel Charles Coy Jan 1993

Visualizing Thermodynamic Stability And Phase Equilibrium Through Computer Graphics , Daniel Charles Coy

Retrospective Theses and Dissertations

In a landmark paper, J. W. Gibbs introduced a fundamental thermodynamic surface for pure materials and, later, expanded that analysis to mixtures. While Gibbs certainly had images of these surfaces in his mind, he described them in words rather than drawings. Since Gibbs time, a number of researchers have produced representations of these surfaces, but their studies have been limited because of the difficulty of creating and visualizing the data sets required. In this work, computer graphics has been used to visualize a variety of these models for pure, binary, and ternary systems;Fundamental-equation surfaces produced from Legendre transforms of ...


Charged Fusions For Enhanced Protein Purification And Immobilization By Ion-Exchange , Meng Hong Heng Jan 1993

Charged Fusions For Enhanced Protein Purification And Immobilization By Ion-Exchange , Meng Hong Heng

Retrospective Theses and Dissertations

This work was undertaken to investigate the enhanced binding of genetically engineered [beta]-galactosidase fusions in ion-exchange. The fusions used had a series of polyaspartate tails of the form: Gly-Asp-Pro-Met-Ala-(Asp)[subscript] n-Tyr fused to the carboxyl termini of the wild type [beta]-galactosidase (BGWT). The resulting fusions carried additional 1, 5, 11, and 16 negative charges and are designated as BGCD1, BGCD5, BGCD11, and BGCD16, respectively;The use of charged fusions for selective protein recovery was studied using hollow fiber ion-exchange membranes. The added tails allowed selective binding and release of [beta]-galactosidase in active form from Escherichia coli ...