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Theses/Dissertations

Chemical engineering

1989

Articles 1 - 6 of 6

Full-Text Articles in Engineering

Fundamental Studies Of Hydrocarbon Conversions Over Supported Bimetallic Catalysts , Mark Wilton Smale Jan 1989

Fundamental Studies Of Hydrocarbon Conversions Over Supported Bimetallic Catalysts , Mark Wilton Smale

Retrospective Theses and Dissertations

The reactions of ethane and ethylene over selected silica-supported group VIII metal catalysts have been investigated using reaction studies and nuclear magnetic resonance (NMR) spectroscopy. The activity of the ruthenium-group IB bimetallic system for the ethane hydrogenolysis reaction was investigated as a function of group IB metal content and ethane and hydrogen partial pressures, while the reactions of ethylene over silica-supported platinum catalysts were studied using NMR;The turnover frequency of the silica-supported ruthenium catalysts for ethane hydrogenolysis as either copper or silver was added tended to change as the group IB metal was first added until a critical point ...


Studies On The Structure And Thermodynamics Of Electrolyte Solutions , Pelin Gevher Özler Jan 1989

Studies On The Structure And Thermodynamics Of Electrolyte Solutions , Pelin Gevher Özler

Retrospective Theses and Dissertations

The theoretical and simulation methods of statistical thermodynamics aim to develope a relationship between the intermolecular potential and various structural and thermodynamic properties for the fluids. Most of the previous work in the literature of electrolyte solutions either depend on primitive model in which only the ionic species are described on a molecular basis or employ sophisticated solvent models to describe the real electrolyte solutions;It has been found that the primitive model does not provide a realistic description for the structure and thermodynamics of electrolyte solutions in a wide range of concentrations. The computer simulations with sophisticated models give ...


Continuous Precipitation Of Yttrium Hydroxycarbonate Spheres Of Narrow Size Distribution , Harold Ray Jouett Ii Jan 1989

Continuous Precipitation Of Yttrium Hydroxycarbonate Spheres Of Narrow Size Distribution , Harold Ray Jouett Ii

Retrospective Theses and Dissertations

Submicron spherical particles of the yttria precursor Y(OH)CO[subscript]3·H[subscript]2O were continuously precipitated in three types of reactors: (1) mixed-suspension mixed-product removal (MSMPR), (2) semi-batch, and (3) packed bed. The homogeneous precipitation occurred as a result of the thermal decomposition of urea in an aqueous yttrium nitrate solution;A wide variety of particle size distributions were produced from these reactors. Mathematical models, which assumed that particle growth was by a diffusion mechanism, successfully allowed the size and shape of the particle size distributions to be predicted and controlled. It was shown that the concentration of ...


An Investigation Of Active And Selective Oxygen In Vanadium Phosphorus Oxide Catalysts For N-Butane Conversion To Maleic Anhydride , Mark Edward Lashier Jan 1989

An Investigation Of Active And Selective Oxygen In Vanadium Phosphorus Oxide Catalysts For N-Butane Conversion To Maleic Anhydride , Mark Edward Lashier

Retrospective Theses and Dissertations

The role of lattice oxygens in two model catalysts, [beta]-VOPO[subscript]4 and (VO)[subscript]2P[subscript]2O[subscript]7, was investigated for the selective and nonselective oxidation of C[subscript]4 hydrocarbons to maleic anhydride and combustion products. Specific catalytic oxygen sites in each model catalyst were labeled with specific amounts of [superscript]18O. Labeled sites were identified by laser Raman spectroscopy and Fourier transform infrared spectroscopy. The level of [superscript]18O enrichment in each site was estimated from the laser Raman spectra and the stoichiometry of reactions involved in the synthesis of the labeled catalysts. Products of ...


Direct Numerical Simulations Of Chemically Reacting Turbulent Flows , Andy David Leonard Jan 1989

Direct Numerical Simulations Of Chemically Reacting Turbulent Flows , Andy David Leonard

Retrospective Theses and Dissertations

This dissertation considers, in three parts, problems concerning mixing and chemical reactions in homogeneous turbulent flows. Direct numerical simulations of finite-rate chemical reactions occurring in moderate Reynolds number turbulence were used to provide data that are difficult to measure experimentally. In the first two parts, models for two phenomena contributing to unknown terms in statistical treatments of reacting flows are considered. In Part I models that are used in the solution of probability density function (pdf) equations are examined, whereas in Part II models used in moment methods for the mean reaction rate are evaluated. In Part III, results of ...


Laser Photodeposition Of Molybdenum Oxide Thin Films From Organometallic Precursors , Kurt Andrew Olson Jan 1989

Laser Photodeposition Of Molybdenum Oxide Thin Films From Organometallic Precursors , Kurt Andrew Olson

Retrospective Theses and Dissertations

Thin films of molybdenum oxides, MoO[subscript] X where 2 ≤ x < 3, were prepared on silicon substrates by laser induced chemical vapor deposition. An excimer laser operating at 193 nm was used to dissociate Mo(CO)[subscript]6 in an oxygen containing atmosphere. The dependence of film properties, such as stoichiometry, morphology, and crystallinity, on various deposition parameters, such as substrate temperature, oxygen concentration, laser pulse rate, pulse intensity, and beam orientation, was investigated. Deposited films were analyzed using Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, Auger electron microscopy, and X-ray diffraction. Raman spectra of solid MoO[subscript]2, [gamma]-Mo[subscript]4O[subscript]11, [eta]-Mo[subscript]4O[subscript]11, [alpha]-MoO[subscript]3, and [beta]-MoO[subscript]3 are reported;Polycrystalline thin films (approximately 600 A) of the electrically and optically anisotropic [gamma]-Mo[subscript]4O[subscript]11 compound were deposited on 100°C substrates. On 60°C substrates, powdery MoO[subscript]2 deposits, indicative of a diffusion limited deposition process, were formed. The process was determined to be photolytically initiated in the gas phase, with perpendicular incidence of the laser beam being necessary to form crystalline films. Various steps in the process leading to [gamma]-Mo[subscript]4O[subscript]11 are discussed;Novel apparatus, designed for performing laser photodeposition and thin film Raman spectroscopy, is presented. Alternative organometallic molybdenum compounds, such as Mo( C[subscript]3H[subscript]5)[subscript]4 and Mo[subscript]2( CF[subscript]3CO[subscript]2)[subscript]4, were prepared and evaluated as precursors for laser photodeposition processes.