Digital Commons Network^™

Process Optimization By Flow Sheet Simulation, Larry Dale Gaines

Doctoral Dissertations

"PROPS, (Process Optimization System), has been used to simulate and optimize the Universal Oil Products solid phosphoric acid catalyst process for producing gasoline. PROPS, a modified version of CHESS (Chemical Engineering Simulation System), performs a complete design and economic evaluation of the process for each set of independent variables. The computational time during optimization was reduced by the use of a regression equation to determine K-values as a function of temperature and pressure. K-value data used for the regression was generated from the Chao-Seader correlation using mixtures of the gasoline components to be encountered during optimization. The regression equation produces …

Metal Salt Catalyzed Carbenoids Ii, Robert Stephen Mcdaniel Jr.

Doctoral Dissertations

"The interaction of diazomalonic esters with olefins in the presence of homogeneous Cu(II) catalyst species has been examined relating to olefin structure effects and catalyst structure effects using partial rate data as a method of determining the mechanistic aspects of the various reactions.

It has been possible to examine the mechanistic details of cyclopropanation, C-H insertion, and both "dimer" forming reactions.

Cyclopropanation proceeds via a transition state including olefin, copper (II), ligands, and carbene C-H insertion results from hydrogen abstraction prior to collapse of the transition state. "Dimer" is formed by the attack of diazo compound on the carbenoid carbon, …

Nucleate Boiling Of N-Pentane, N-Hexane And Several Mixtures Of The Two From Various Tube Arrays, Kenneth Wayne Wall

Doctoral Dissertations

"An investigation of nucleate boiling heat transfer in saturated pools of Normal Pentane, Normal Hexane and several mixtures of the two was conducted. The fluids were boiled from gold-plated, copper, cylindrical heat transfer surfaces, 4.96 inches long, and 1.048 inch in diameter. The heat transfer elements were boiled in varying vertical tube arrays at a pressure of 14.70 psia.

It was found that the mixtures boiled with a lower heat transfer coefficient than that for either pure component when boiled alone. When boiling in any of the tube bundle arrangements, the heat transfer coefficients for the upper tubes in the …

Methods And Applications Of The Mean-Variance Portfolio Selection Model, John W. Marsh

Doctoral Dissertations

"The Mean-Variance portfolio selection model, or Efficient Market model, is examined in terms of the small investor. The performance is first tested on the small sample space of the thirty Dow Jones Industrials. The results show that it is possible to outperform the market by investing in the minimum-variance, or safest, portfolio. The Critical-Line algorithm as developed by Markowitz and modified by Sharpe is used in this analysis.

Since the Critical-Line algorithm is very time-consuming and does not always converge to a solution, an alternate algorithm is developed. This algorithm, referred to as the “Simplified Algorithm”, is designed to find …

Kinetic And Thermodynamic Acidities Of Selected Weakly Acidic Hydrocarbons, Darrell R. Strait

Doctoral Dissertations

"The kinetic and thermodynamic acidities in methanol for bromoform and phenylacetylene have been determined at various temperatures. The thermodynamic acidities of phenylacetylene were obtained through a quench method which involved tritium tagging of the phenylacetylene anions present at equilibrium. With the use of this method, a pK_a of 18.34 for phenylacetylene at 0ºC was obtained. Through the use of these acidities, it was shown that the kinetics for these proton exchange processes are not diffusion controlled.

Isotope effects ( k_H/ k_D) were obtained for chloroform, bromoform and phenylacetylene at three temperatures (0ºC, -10ºC and -20ºC). …

On Integrability And L¹ Convergence Of Certain Cosine Sums, John William Garrett

Doctoral Dissertations

"Rees and Stanojevic altered the standard cosine series and obtained a necessary and sufficient condition for integrability of the altered sum. Here these sums are generalized, and it is shown that such sums converge in L¹-norm"--Abstract, page iv.

Numerical Modeling Of The Early Stage Of Cloud Formation In A Simulation Chamber, Adel Nassif Saad

Doctoral Dissertations

"A numerical model has been developed to simulate the growth of cloud droplets by condensation upon a spectrum of hygroscopic nuclei. The model is applicable to cloud simulation chamber conditions as well as to the study of the role of these nuclei on cloud base microstructure.

Equations are given for the growth by condensation of water vapor on a population of hygroscopic nuclei in a volume being cooled by expansion. The equations are integrated simultaneously, using Hamming's modified predictor-corrector method for given initial conditions, to obtain the droplet size distribution, temperature, pressure, supersaturation, and liquid water content. Temperature fluctuations, sedimentation …

Solvability Of Differential Systems Near Singular Points, Leon M. Hall

Doctoral Dissertations

"Functional analysis techniques are used to prove a theorem, analogous to the Harris-Sibuya-Weinberg theorem for ordinary differential equations, which yields as corollaries a number of existence theorems for holomorphic solutions of linear functional differential systems of the form z^Dy'(z) = A(z)y(z) + B(z)y(αz) + C(z)y'(αz) in the neighborhood of the singularity at z = 0"--Abstract, page 2.

The Look Of The Play: Dramatic Focus In Shakespeare's Early History Plays, Barbara Covington Hodgdon

Doctoral Dissertations

No abstract provided.

Solvent Effects Upon Substitution Reactions Of Metal Complexes, Dagoberto Pacheco Alvarez

Doctoral Dissertations

No abstract provided.

Removal Of Nutrients By Sorption On Activated Alumina, Checkman Michael Yue

Doctoral Dissertations

"The nutrient enrichment of surface, primarily impounded, water and the associated problems of accelerated eutrophication and prolific algal growth have become a nationwide concern. Phosphorus and nitrogen are considered to be the key elements in abating eutrophication and are contributed from many sources, natural and manmade; prominent among these is the discharge of domestic and industrial wastes.

The purpose of this study was to evaluate the removal of nutrients, primarily phosphorus and nitrogen, with activated alumina using a continuous-flow pilot plant system. Specific objectives were the: development and construction of appropriate bench and field-scale pilot plant units utilizing the rapid …

The Effect Of Contact Angle, Surface Roughness, And Adsorption Of Heterogeneous Nucleation Of Condensing Water, Prafulla Chandra Mahata

Doctoral Dissertations

"Condensation of water vapor on various surfaces was studied experimentally. It was found that supersaturations as high as 25% were required to initiate condensation on hydrophobic surfaces. The supersaturation data agreed qualitatively with the Volmer theory of heterogeneous nucleation. The influence of adsorption of water vapor was found to be small. Surface roughness caused a little reduction in the critical supersaturation"--Abstract, page iii.

Hydrodynamic Mixing Model Applied To A Continuous Stirred-Tank Reactor With And Without Second-Order Reaction, Leon L. Otte

Doctoral Dissertations

Paper 1: "A hydrodynamic mixing (HDM) model, used to calculate the steady-state spatial distribution of conversion for a second-order reaction in a continuous stirred-tank reactor (CSTR) for non-premixed reactants was developed and contrasted with other methods. The HDM model is based on a segmental description of the reactor and includes turbulent mixing effects in each segment. As a test of the model, the experimental results obtained from a tubular reactor were found to be very well represented for a range of reactant ratios. Spatial distributions of concentration and segregation intensity (degree of mixing) within the CSTR were determined for a …

Solid Transformations And Premelting Phenomena In Fluorite Structures And The System Srcl₂Bacl₂, Damri Sukhotanang

Doctoral Dissertations

"Thermal expansion and phase transformations in CaF₂, BaF₂, SrCl₂, and BaCl₂ were studied by high temperature x-ray diffractometry, differential thermal analysis, and thermodilatometric analysis. Thermal expansion characteristics of CaF₂, BaF₂ and SrCl₂ are very similar. The structures expand normally at lower temperatures and depart substantially from linearity at higher temperatures, because of formation of defects and disordering of anions. At high temperatures CaF₂ and BaF₂ react with water vapor, even at low humidities, forming oxides and emitting HF, leading to difficulty in observation of phase transformations. SrCl …

Surface Elastic Waves In Piezoelectric Semiconductors And Layered Media, Yu-Pin Han

Doctoral Dissertations

"The primary interest of this investigation is to understand the surface elastic wave properties in piezoelectric semiconductors and layered media. Generalized piezoelectric wave equations in piezoelectric semiconductors and layered media are derived. Systems considered are the piezoelectric semiconductor, the two layer piezoelectric insulator-semiconductor, the three layer piezoelectric insulator- gap-semiconductor and the four layer piezoelectric insulator-gap-semiconductor-dielectric substrate. The eigenwave expansion and the iteration methods in the complex domain are used to solve the problems. Mathematically, it represents a solution of the eigenvalue boundary value problem which involves iteration of functions in the complex domain. Solutions obtained are eigenvalues and eigenvectors which …

Towards A Design Of Hmo, An Integrated Hardware Microcode Optimizer, James Oliver Bondi

Doctoral Dissertations

"This paper discusses an algorithm for optimizing the density and parallelism of microcoded routines in micro-programmable machines. Besides presenting the algorithm itself, this research also analyzes the algorithm's uses, design integration problems, architectural requirements, and adaptability to conventional machine characteristics. Even though the paper proposes a hardware implementation of the algorithm, the algorithm is viewed as an integral part of the entire microcode generation and usage process, from initial high-level input into a software microcode compiler down to machine-level execution of the resultant microcode on the host machine. It is believed that, by removing much of the traditionally time-consuming and …

An Analytical And Experimental Study Of The Dynamic Response Of A Press, Woosoon Bai

Doctoral Dissertations

"This dissertation presents a simplified mathematical model and computer simulation of the vertical motion of a press. The model is verified by comparing simulation results with actual field measurements.

Using this model, the computer simulation is then extended to study the dynamic response of a bolted press, one with loosened anchor bolts, and one which is isolated. Press performance, in terms of acceleration of the press, velocity of its foundation, and forces transmitted to the foundation, is analyzed in relation to the foundation mass and the stiffness of the isolators, where applicable. Comparative performances of the presses secured by the …

Phase Equilibria And Transformations In Potassium Sulfate, Chromate, Molybdate, And Tungstate, Roy Richard Ramey

Doctoral Dissertations

"Thermal expansion and transformations of K₂SO₄, K₂CrO₄, K₂MoO₄, and K₂WO₄ were studied by high temperature diffractometry, differential thermal analysis, and dilatometry. K₂SO₄ and K₂CrO₄ transform from an orthorhombic to a hexagonal structure at 580°C and 670°C respectively, with initiation of the transformation probably related to increased amplitude of S-O tetrahedral vibrations. K₂MoO₄ and K₂WO₄ transform from a monoclinic to an orthorhombic structure at 300° and 370°C respectively. A minor K₂MoO_{4 …}

Cross Sections For Photoionization Of The 6²P-Fine Structure Levels Of Cesium, John Daniel Jones

Doctoral Dissertations

"The cross sections for photoionization of excited cesium from the 6²P_3/2- and 6²P_1/2-fine structure levels have been measured using a triple crossed-beam apparatus. Two photon beams, one for excitation and one for ionization, impinge upon an atomic beam and produce ions at the point of intersection. The relative cross section is determined from a knowledge of the ion count rate and the relative photon flux of the ionization light. The results are normalized to available theoretical calculations and compared with recombination measurements in cesium plasmas. The present cross sections are found to decrease with …

State-Space Analysis And Synthesis Of Active Rlc Networks, Wen-Pao Lee

Doctoral Dissertations

"This dissertation provides theoretical foundations for the state-space analysis and synthesis of linear active RLC networks containing all four types of controlled sources. The analysis portion is concerned with an explicit representation of the state model and the order of complexity of a general linear active RLC network. The problem considered in the synthesis portion is the realization of a given A-matrix with an active nondegenerate RLC-ladder network or an active RLC network without any particular structure.

The general active RLC network state model representations are explicitly expressed in terms of the fundamental circuit submatrices, the network element submatrices, and …

Parameter Identification Of Nonuniform Distributed Rc Networks, Roger Allen Hayes

Doctoral Dissertations

"The problem of the unique parameter identification of nonuniform distributed RC networks is addressed in this dissertation. Previous literature provides for the equivalence of distributed networks with respect to the terminal characteristics. Therefore, the question is whether unique parameter identification is even possible. This work settles that question by presenting the sufficient conditions to insure a unique solution to the parameter identification problem. One theorem requires the knowledge of a driving-point impedance, the knowledge of the physical length, and the constraint that the r(x)c(x) product remains constant to insure uniqueness of the parameters r(x) and c(x). Relaxation of the r(x)c(x) …

A Study Of The Kinetic And Thermodynamic Properties Of Carbon Acids In Methanol, Dennis L. Filger

Doctoral Dissertations

The thermodynamic acidity (pK_a) of iodoform in methanol was determined at 25°C and 35°C; the values are 18.74 and 18.05, respectively . These acidity constants were determined by a modification of the equilibrium quenching technique which involves the conversion of the conjugate base of iodoform, present at equilibrium, to the radioactively labelled acid.

The rate constants for the methoxide-catalyzed hydrogentritium exchange of chloroform, iodoform, 9-phenylfluorene and indene were determined in methanol at various temperatures. The second-order rate constants obtained from these studies were shown to be the rate constants for removal of a triton. The activation parameters (ΔH …

Rc-Gyrator Ladder And Rlc Symmetrical Lattice Network Synthesis - A State-Space Approach, Tien Hua

Doctoral Dissertations

"This dissertation presents two network realization procedures using the state-space approach. The first procedure is the realization of a transfer function. A state model (A,B,C,D) is obtained from the given transfer function by inspection, where A is a companion matrix. Through a similarity transformation T, another state model (F,G,H,J) is obtained, where F is a tridiagonal matrix and can be realized by a RC-gyrator ladder network. The input source is inserted in the proper position of the ladder network, and the output is obtained through a summing circuit. It is a unified procedure and uses simple algebraic computation. A general …

Base-Induced Reactions Of P-Nitrobenzyl Compounds, Paul Henry Ruehle

Doctoral Dissertations

"The base-induced reactions of several p-nitrobenzyl compounds were studied. The products varied with changes in the leaving groups. With relatively poor leaving groups (Cl, S⁺(Me)₂), p,p'- dinitrostilbene was produced in good yield. The products of the reaction of p-nitrobenzyl chloride and hydroxide ion in 50% aqueous dioxane were 52.0% p,p'-dinitrostilbene, 43.9% cis- and trans-p,p'-dinitrostilbene oxides, 3.2% p-nitrobenzyl alcohol, and traces of other compounds. With dissolved oxygen, no stilbene was produced; the main product was 88% cis- and trans-p,p'-dinitrostilbene oxides. The addition of small amounts of di-t-butyl nitroxide caused a decrease in both the rate of the reaction and the amount …

A Study Of Exothermic Chemical Reaction In A Porous Catalyst Wedge, Joseph Michael Schardl Jr.

Doctoral Dissertations

"Temperature and composition were measured at various locations in a system where ethylene is hydrogenated to ethane on a 1/4 inch porous catalyst wedge made of nickel supported on alumina. 'When the wedge of catalyst was bathed in hydrogen, experimental results indicated a high temperature rise from the feed temperature to the catalyst which is implied by the diffusion controlled regime for solid catalyzed, highly exothermic reactions. This high activity was reversibly reduced by bathing the catalyst wedge in nitrogen for extended time periods (greater than 24 hours). This nitrogen soaking changed the experimental conditions from those of diffusion controlled …

Surface Electromagnetic Waves With Damping I. Isotropic Media Ii. Anisotropic Media, Gary Shannon Kovener

Doctoral Dissertations

Paper 1: “Surface electromagnetic wave (SEW) dispersion curves are usually calculated using a simple equation derived from Maxwell’s equations and boundary conditions. When complex dielectric functions are used for the two media, the component of the propagation vector along the surface k_x becomes infinite as the frequency ω approaches the surface polariton frequency ω_s if ω is considered complex and k_x real. On the other hand, if k_x is considered complex and ω real, the dispersion curves bend back toward smaller k_x as ω approaches ω_s. We have previously demonstrated that both types …

The Morphology Of Cellular Precipitation In Magnesium Rich Magnesium-Aluminum Alloys, Jyong Shi Cho

Doctoral Dissertations

"The morphology of cellular precipitation in a Mg-9wt. %AI alloy has been investigated by light and electron microscopy. A study of the early stages of the cellular precipitation process indicated that cellular precipitate structure forms in Mg-Al alloys by Fournelle and Clark mechanism. "Replacive" motion indicative of the Tu and Turnbull mechanism for cellular precipitation was not seen"--Abstract, page 1.

Methods For Predicting The Influence Of Intense Sound, Steady Flow, And Elevated Temperature On The Acoustic Performance Of Automotive Exhaust System Components, Richard Chuka Oboka

Doctoral Dissertations

"The principal objective of this investigation was to study the feasibility of developing laboratory techniques for automobile-exhaust muffler design in order to reduce the amount of on-vehicle trial-and-error testing currently required. The investigation included (1) improving the capability of existing laboratory equipment to simulate the conditions in automobile exhaust (i.e., high-amplitude pressure waves, steady flow, and elevated temperature), and (2) theoretical and experimental studies of typical acoustic elements (side-branch resonators, expansion chambers, louvered tubes) used in muffler design. The sound fields used for these studies included pure tones, single pulses (tone bursts), random noise, and simulated automobile exhaust noise.

Empirical …

Not Another Poetess: A Study Of Female Experience In Modern American Poetry, Jeannine Dobbs

Doctoral Dissertations

No abstract provided.

Physiological Ecology Of Four Species Of Polysiphonia, Richard A. Fralick

Doctoral Dissertations

No abstract provided.