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Full-Text Articles in Engineering

Characterizing Growth Rates And Growth Rate Dispersion Of Secondary Nuclei As A Function Of Supersaturation , Christopher Michael Jones Jan 1999

Characterizing Growth Rates And Growth Rate Dispersion Of Secondary Nuclei As A Function Of Supersaturation , Christopher Michael Jones

Retrospective Theses and Dissertations

The growth rates of secondary crystal nuclei determine the number of crystals that will reach a size large enough to contribute to the final product mass in a crystallization process. Contact nuclei were chosen for study because crystals nucleated under conditions of low supersaturation are formed by contact or secondary nucleation. High supersaturation levels are required for primary nucleation to occur. Growth rate dispersion complicates the prediction of growth rates and product size distributions. Having growth rate dispersion in a crystallizing system means that despite the population of crystals having all been nucleated and grown under identical conditions, they grow ...


Design Of A Bioartificial Nerve Graft , Gregory Edward Rutkowski Jan 1999

Design Of A Bioartificial Nerve Graft , Gregory Edward Rutkowski

Retrospective Theses and Dissertations

Nerve injuries complicate successful rehabilitation more than any other form of trauma because of loss of protective sensibility and tactile discrimination, denervation atrophy of muscles, and pain syndromes. While achieving full function and organ reinnervation after peripheral nerve injury is a challenge, a promising method of improving the rate and success of regeneration is the bioartificial nerve graft (BNG). The BNG developed in the laboratory consists of a porous bioresorbable tube containing cultured Schwann cells that help to direct and support nerve regeneration when used to bridge the gap between the ends of the severed nerve;To aid in the ...


Development And Scale-Up Of Particle Agglomeration Processes For Coal Beneficiation , Meiyu Shen Jan 1999

Development And Scale-Up Of Particle Agglomeration Processes For Coal Beneficiation , Meiyu Shen

Retrospective Theses and Dissertations

The development of two modified agglomeration processes for coal beneficiation is presented separately in Parts I and II of this dissertation. Part I is based on research which was conducted to study the mechanism and characteristics of a gas-promoted oil agglomeration process. Part II is based on research which was carried out to develop a newer and more innovative method for agglomerating coal particles with microscopic gas bubbles in aqueous suspensions;In Part I, the development of a gas-promoted oil agglomeration process for cleaning coal was carried out with scale model mixing systems in which aqueous suspensions of ultrafine coal ...


Metal Cluster Hydrodesulfurization Catalysts Based On Ternary Molybdenum Sulfides , Robert Kirk Thompson Jan 1999

Metal Cluster Hydrodesulfurization Catalysts Based On Ternary Molybdenum Sulfides , Robert Kirk Thompson

Retrospective Theses and Dissertations

Catalysts based on metal sulfide cluster compounds such as Chevrel phases (MxMo6S8) have been shown to possess high activity and selectivity for hydroprocessing reactions. Previous methods of preparing crystalline Chevrel phases have involved high temperature, solid-state synthetic routes which produce low surface area materials (0.1--1.0m2/gm). In our recent research, lower temperature syntheses via solution precursors have been explored as routes to these materials. The discovery of a new class of compounds, M2x/n n+(Mo6S8)Sx (n = 1--3) has resulted. These new reduced ternary molybdenum sulfides have been shown to have both high activity and selectivity in ...


Development Of An Empirical Model Of Human Sweating And A Semi-Empirical Model Of Human Thermoregulation , Jennifer Jane Walker Jan 1999

Development Of An Empirical Model Of Human Sweating And A Semi-Empirical Model Of Human Thermoregulation , Jennifer Jane Walker

Retrospective Theses and Dissertations

The physiology of the human thermoregulatory response to changes in environment and work load has been studied from the perspective of both the physiologist and the engineer. Both fields have brought certain skills and tools to the effort. An effort to bring together the understanding gained from these two perspectives has been lacking. In this work a model for the sweat response and a model for the thermoregulatory response to changes in room temperature were developed. These models were developed using the modeling tools of engineering and the knowledge contained in past experimental data;An empirical model of the sweat ...


Enhancing Chromatographic Separations Of Recombinant Proteins From Canola Extracts By Genetic Design And Characterization Of Protein Binding Regions , Chenming Zhang Jan 1999

Enhancing Chromatographic Separations Of Recombinant Proteins From Canola Extracts By Genetic Design And Characterization Of Protein Binding Regions , Chenming Zhang

Retrospective Theses and Dissertations

Canola was studied as an alternative source to traditional microbial systems as a recombinant protein production host. Various chromatographic methods were used in this work to systematically characterize the native canola protein elution profiles, and different genetically engineered proteins were selected to explore the opportunities presented for effective protein recovery;Native canola protein was eluted into two major peaks in linear salt gradient elution on cation-exchange chromatography. T4 lysozyme and its mutants, by both point mutation and fusion, were used as model proteins to investigate the charge effect on protein elution. It was found that the single mutant T4 lysozyme ...


Triphase Catalysis: Mass Transfer And Kinetic Studies , Holger Jürgen Glatzer Jan 1999

Triphase Catalysis: Mass Transfer And Kinetic Studies , Holger Jürgen Glatzer

Retrospective Theses and Dissertations

The importance of phase transfer catalysis (PTC) in the production of high value chemicals has grown immensely over the past few years. PTC may be a suitable method to synthesize a product whenever each reactant is miscible in a different phase. By addition of a PT catalyst, which functions as a ferrying agent between the phases, significant rate enhancements can be achieved;The PT catalyst (e.g. a quaternary ammonium salt) is usually used in soluble form. Alternatively, it can be bound to a solid support. The latter technique is called triphase catalysis (TPC). It has operational advantages over conventional ...


High Pressure Crystallization Of Purafect® Subtilisin , Ruta Yeshwant Waghmare Jan 1999

High Pressure Crystallization Of Purafect® Subtilisin , Ruta Yeshwant Waghmare

Retrospective Theses and Dissertations

The aim of this work was to study the effect of high pressure on kinetics of subtilisin crystallization and to use high pressure as a means to better understand the mechanism of crystallization;It is known that the effect of hydrostatic pressure on conformation varies with the protein being studied. To determine the effect of high pressure on the conformation of subtilisin, activity assays were used in addition to FTIR spectroscopy. Pressures up to 100 MPa were found to cause no irreversible conformational changes in subtilisin;To study the effect of high pressure on subtilisin crystallization, a factorial experiment was ...


In Situ Vibrational Spectroscopic Investigation Of C4 Hydrocarbon Selective Oxidation Over Vanadium-Phosphorus-Oxide Catalysts , Zhi-Yang Xue Jan 1999

In Situ Vibrational Spectroscopic Investigation Of C4 Hydrocarbon Selective Oxidation Over Vanadium-Phosphorus-Oxide Catalysts , Zhi-Yang Xue

Retrospective Theses and Dissertations

n-Butane selective oxidation over the VPO catalyst to maleic anhydride is the first and only commercialized process of light alkane selective oxidation. The mechanism of this reaction is still not well known despite over twenty years of extensive studies, which can be partially attributed to the extreme difficulties to characterize catalytic reactions real-time under typical reaction conditions. In situ spectroscopic characterization techniques such as infrared spectroscopy and laser Raman spectroscopy were used in the current mechanistic investigations of n-butane oxidation over VPO catalysts;To identify the reaction intermediates, oxidation of n-butane, 1,3-butadiene and related oxygenates on the VPO catalyst ...


A Knowledge-Based Approach For Data Reconciliation Of Process Networks , Maria Victoria Balagat Bascuñana Jan 1999

A Knowledge-Based Approach For Data Reconciliation Of Process Networks , Maria Victoria Balagat Bascuñana

Retrospective Theses and Dissertations

Because the area of gross error detection and data reconciliation has received a significant amount of attention in the past two decades, the problem is fairly well-defined but the solutions have yet to be perfected. Also, despite the proliferation of new methods that offer particular strengths and the potential economic value of this data analysis step, it has not been as widely performed in chemical manufacturing plants because of the difficulties, both mathematical and instrumental, that plant operators encounter. Hence, the focus of this dissertation is the simplification of the gross error detection and data reconciliation problems at hand using ...