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Theses/Dissertations

Chemical engineering

1987

Articles 1 - 9 of 9

Full-Text Articles in Engineering

Measurement Of Agglomerate Strength Distributions In Agglomerated Powders , Muhsin Ciftcioglu Jan 1987

Measurement Of Agglomerate Strength Distributions In Agglomerated Powders , Muhsin Ciftcioglu

Retrospective Theses and Dissertations

A new technique for measuring the strength distributions of powder agglomerates was developed. It involves the use of a calibrated ultrasonic sound field. The strength distributions of hollow glass microspheres were determined independently by mercury porosimetry, and then used to calibrate the sound field; breaking pressures from 1 to 76 MPa could be obtained by varying the energy input to the ultrasonic transducer;Agglomerate strength distributions were measured for a variety of yttria and yttria-stabilized zirconia powders, which were prepared by solution precipitation methods. Different preparation methods were used in order to obtain powders containing agglomerates with different characteristics. Special ...


Use Of Sol-Gels In The Application Of Ceramic Oxide Thin Films , Bradley Alan Paulson Jan 1987

Use Of Sol-Gels In The Application Of Ceramic Oxide Thin Films , Bradley Alan Paulson

Retrospective Theses and Dissertations

Metal oxide sol-gels were produced through a controlled hydrolysis-condensation reaction of the metal alkoxide in alcohol using nitric acid as a catalyst. In obtaining sols of niobia, tantala, and titania, increasing either the water content or the system concentration increased the rate of gelation. However, while a sufficient amount of nitric acid was required to promote the condensation of the metal oxide and inhibit the precipitation, increasing the amount of nitric acid beyond that point slowed the gelation rate. A sufficient excess of water also lead to precipitation. These systematic parameter investigations were used to obtain sols of bismuth oxide ...


Low-Alumina Portland Cement From Lime-Soda Sinter Residue , Jason Allen Chesley Jan 1987

Low-Alumina Portland Cement From Lime-Soda Sinter Residue , Jason Allen Chesley

Retrospective Theses and Dissertations

A byproduct for the Ames Lime-Soda Sinter Process for recovering alumina from power plant fly ash was investigated as a cement raw material. This investigation dealt with a determination of the best method to utilize the process residue from both a clinker quality and an economic perspective. The experimental work was divided into 4 major areas: characterization of the sinter residue, laboratory burnability tests, physical testing of produced residue-cements, and a kinetic study of C[subscript]3S formation. Other important topics were considered such as the effect use of the sinter residue has on the energy requirements of a commercial ...


Protein Precipitation With Acids And Polyelectrolytes: The Effects Of Reactor Conditions And Models Of The Particle Size Distributions , Rod R. Fisher Jan 1987

Protein Precipitation With Acids And Polyelectrolytes: The Effects Of Reactor Conditions And Models Of The Particle Size Distributions , Rod R. Fisher

Retrospective Theses and Dissertations

The importance of the mixing environment during precipitation has been examined in two systems. In the first, isoelectric fractionation of the two major proteins of soy was characterized. Two extremes in the speed of acid addition (rapid, with no mixing, and slow, via acid dialysis, with complete mixing) are compared to determine their effects on the properties of the precipitate. Total protein yield, fraction composition, and aggregate microstructure did not depend significantly on the method of acid addition. Particle size distribution and hindered settling behavior did differ and were explained using a model of aggregate strength;In the second system ...


Measuring Effective Diffusivities In Porous Pellets: Experimental Procedures And Fft Calculations , James Edward Klein Jan 1987

Measuring Effective Diffusivities In Porous Pellets: Experimental Procedures And Fft Calculations , James Edward Klein

Retrospective Theses and Dissertations

The effective diffusivity, D[subscript] e, of He in N[subscript]2 in ZnS pellets was determined using a dynamic Wicke-Kallenbach diffusion cell at 1.5 atm and 23°C. Pellets were pressed from reagent powders in rings with internal diameters of 25.4 mm. Pellet lengths ranged from 3.43 to 23.34 mm;Diffusivities were calculated by minimizing the sum-of-squares error, in the frequency domain, between the experimental data and a model for diffusion through the pellet. The experimental data were transformed to the frequency domain via the fast Fourier transform (FFT) and the Laplace transform solution of ...


Characterization, Kinetics, And Subsite Mapping Of Aspergillus Niger Glucoamylases I And Ii, And Partial Purification And Characterization Of A Chainia Endo-Xylanase , Michael Martin Meagher Jan 1987

Characterization, Kinetics, And Subsite Mapping Of Aspergillus Niger Glucoamylases I And Ii, And Partial Purification And Characterization Of A Chainia Endo-Xylanase , Michael Martin Meagher

Retrospective Theses and Dissertations

This dissertation is the account of investigations into the kinetic characterization and subsite mapping of two forms of glucoamylase from Aspergillus niger, and the partial purification and physical and kinetic characterization of an endo-xylanase from the genus Chainia;Glucoamylase I (GAI) and glucoamylase II (GAII) were initially purified from a commercial preparation by ammonium sulfate precipitation and separated from each other by anion-exchange column chromatography with a decreasing linear pH gradient. The two forms were free of transglycosylase, but exhibited microheterogeneity upon disc gel electrophoresis, sodium dodecyl sulfate electrophoresis, and isoelectric focusing;Both forms were subsite-mapped by determining their maximum ...


Investigation Of The Catalytic Behavior And Chemical Nature Of Alkali Promoted Copper And Copper-Cobalt-Chromium Oxide Catalysts For The Conversion Of Synthesis Gas To Methanol And Higher Alcohols , Gordon R. Sheffer Jan 1987

Investigation Of The Catalytic Behavior And Chemical Nature Of Alkali Promoted Copper And Copper-Cobalt-Chromium Oxide Catalysts For The Conversion Of Synthesis Gas To Methanol And Higher Alcohols , Gordon R. Sheffer

Retrospective Theses and Dissertations

The work completed for this dissertation has endeavored to identify the active phase(s) for the synthesis of normal alcohols by carbon monoxide hydrogenation with the alkali promoted copper-cobalt-chromium catalyst system patented by the Institut Francais du Petrole. Initial work investigated the effects of a variety of preparation parameters on catalytic activity and selectivity. It was found that special attention must be paid to catalyst calcination temperature. At low calcination temperatures, alcohol selectivities as great as 70 wt % with a production yield of 0.12 g alcohol/g catalyst/hr were obtained. This is the greatest selectivity and yield yet ...


Prediction Of Ionic Structure In Hydrocarbon Flames , Ahmet Nedim Eraslan Jan 1987

Prediction Of Ionic Structure In Hydrocarbon Flames , Ahmet Nedim Eraslan

Retrospective Theses and Dissertations

The objective of this research is to model the appearance and behavior of combustion-generated ions in hydrocarbon flames. An understanding of ionic phenomena is important to the development of advanced combustion technology including electrical control of flame structure and suppression of soot formation. Computer models have been developed to evaluate the formation and behavior of ions in acetylene flames;The results of computations are compared to experimental data of other researchers. Several important qualitative features have been successfully modeled. Peak ion concentrations of 10('9) to 10('11) cm('-3) are consistent with experimental measurements. The ratio of large ions ...


Thermodynamics Of Embryogenesis , Scott D. Pearson Jan 1987

Thermodynamics Of Embryogenesis , Scott D. Pearson

Retrospective Theses and Dissertations

Many investigators have attempted to gain insight into the thermodynamics and energetics of growth by correlating various parameters with metabolic activity. Interpretation of these expressions was often difficult. Frequently terms without physical meaning appear. The purpose of this research project is to develop mathematical relationships that adequately describe embryonic energetics, both within the growing organism and in the surrounding microenvironment, using fundamental chemical principles;In this work two growth models are proposed: one is formulated from equilibrium thermodynamics and kinetics while the other utilizes nonequilibrium thermodynamic principles. The models are based on a small set of basic metabolic reactions that ...