Digital Commons Network^™

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 …

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 …

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, …

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 …

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 …

Kalman Filter Equalization For Qpsk Communications, Tze-Shen Lee

Doctoral Dissertations

"The discrete complex Kalman filter is considered as an equalizer for quadrature phase shift keyed (QPSK) systems in the presence of additive noise and intersymbol interference (ISI). For a known linear time-invariant channel with finite duration impulse response, the finite n-dimension complex Kalman filter equalizer is able to reduce the degradation caused by ISI. When the channel is unknown, an adaptive Kalman equalizer is used in which the channel complex tap gains are estimated by decision feedback. A two component multipath channel QPSK system is used as an example. Using the Chernoff upper bound to calculate the error probabilities, the …

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 …

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 …

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 …

In Vitro Studies Of Lipid Uptake By Medical Grade Silicone Rubbers Used For Heart Valve Balls, Shu Hua Wu

Doctoral Dissertations

"Various chemical and physical aspects of high lipid absorption by medical grade silicone rubber and the dynamic mechanical properties of lipid-rubber systems were studied in order to provide an insight into the problem of 'variance' of these materials when subjected to 'in vitro' and 'in vivo' environments. Wide variations of post cure procedures of the silicone rubber were studied. Different post cures did not appreciably affect the mechanical properties of the silicone rubber. Mass transfer studies demonstrated that the diffusion of linolenic acid into a silicone rubber slab is a purely physical diffusion process (D = 3.2 x 10^{-3 …}

A Finite Element Method For Three-Dimensional Analysis Of Metal Forming, Nguyen Don Phu

Doctoral Dissertations

"The importance of metal forming by extrusion was reviewed. A Finite Element Approach was developed to analyze extrusion processes. A brick type linear element and the Upper Bound theorem were used to analyze the extrusion of a cylindrical billet into a square cross-section prism. A minimization technique for a non-linear functional with linear constraints was developed. Different types of boundary conditions were also formulated. A frictionless extrusion was simulated using the computer program developed. Velocity profiles at different sections of the deforming solid were obtained and an average extrusion pressure was predicted for a given area reduction ratio.

Extrusions from …

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) …

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 …

Transition Boiling Of Normal Pentane From A Horizontal Flat Gold Surface, Ronald M. Canon

Doctoral Dissertations

"The characteristic boiling curve for Normal Pentane was determined at 1 atmosphere pressure with particular attention devoted to the transition boiling region. The heat transfer surface was a horizontal, gold-plated, copper disc.

Stability analysis was employed to demonstrate why previous investigators have had only limited success in collecting data in the transition region and to provide a valid basis for equipment designed to operate in this region.

A method of predicting the transition region boiling curve from the nucleate curve and the Liedenfrost point is presented. The method was found to predict the transition boiling of Normal Pentane, Freon 12, …

Structural Behavior Of Cold-Formed Steel Members Made Of Thick Sheets And Plates, Ai-Shen Liu

Doctoral Dissertations

"It is well-known that the current AlSI Specification for the design of cold-formed steel structural members has been developed mainly for thin steel sections. In order to extend the applicability of the specification for the design of cold-formed steel members thicker than 1/4 in., both analytical and experimental investigations have recently been conducted with special emphases on the effects of cold work on the mechanical properties of corners and the strength of bolted connections.

For the effects of cold work, previous investigations have shown that the phenomena of strain hardening and strain aging are main factors which affect the mechanical …

Double Reflection Dips - From Grating Ruled Semiconductors, Le-Fu Teng

Doctoral Dissertations

"The double dips, previously observed by Fischer, Anderson, et al., which appeared in the reflection spectra of grating surfaces on the Te-doped semiconductors GaAs and InSb around the plasmon and phonon frequencies have been measured in more detail. In the plasmon region, several possible explanations of the phenomenon are discussed. A simple equation checked with the rigorous theory is proposed and is shown to fit the data well. In the phonon region, the extra dip is calculated and identified as being caused by surface phonons"--Abstract, page ii.

On Interaction In The Two-Way Aov Model Without Replication Including Power Comparisons Of Two Tests For Non-Additivity, Victor John Hegemann

Doctoral Dissertations

"Data analysts have long been concerned with the problem of giving a complete analysis of the two-way crossed classification design with one observation per cell when interaction is present in the data. Conventional tests of hypotheses and statistical inferences are not applicable in this case since an estimate of the error variance is not available. Transformation of the data to additive data has been one solution to this problem; however, interpretation of the physical units of the transformed data is difficult. Recent contributions to the analysis of this design include a test for interaction, a test for testing differences in …

Direct And Inverse Heat Conduction In Rock Materials Using The Finite Element Method, Vernon Dale Allen

Doctoral Dissertations

"A finite element method is presented for solution of direct and inverse heat conduction problems in rock materials. Finite element programs for direct and inverse heat conduction problems were developed and demonstrated. Flow charts are given for the finite element programs.

The direct finite element heat conduction program changes material properties with temperature to approximate the temperature dependent properties of rock materials. An example problem was solved by the finite element method and also using Kirchoff's transformation. The finite element solution compared quite well with the Kirchoff transformation solution.

The inverse method utilizes the direct finite element heat conduction program …

Dropwise Condensation As Affected By Vapor Diffusion And Molecular Sticking, Salil K. Banerjee

Doctoral Dissertations

"Experimental values of heat flux in dropwise condensation on a gold plated vertical copper surface were determined in presence and absence of (or minute traces of) noncondensable gas. The noncondensable gas concentration varied from 0.0045% to 7.5% over a range of subcooling from 2.155 to 17.13°F and system pressure of 4.124 to 16.67 psia. The calculated heat transfer coefficient ranged from 1,545 to 11,135 Btu/hr-ft²-°F. In the part of the experiment where precautions were taken to avoid the presence of noncondensable gas in the water vapor, much higher values of heat flux were observed. Values of heat transfer coefficient ranging …

Mathematical Simulation Of Gas And Water Coning In Petroleum Reservoirs By The Dynamic Material Balance Technique, Visheshwar Nath Simlote

Doctoral Dissertations

"The prediction of coning behavior at a producing oil well is one of the most difficult numerical simulation problems. Because of the convergent flow patterns and small sizes of the inner grid blocks, the radial coordinate models used to study the problem have a tendency to become unstable. Since several hundred pore volumes may flow through the inner grid blocks during a rather small time interval, instabilities are likely to occur in the saturation calculations for these grid blocks. The dynamic approach to saturation calculations is a method which first computes the correct material balance and then calculates the saturation …

Measurements Of Condensation Coefficient Exhibited By Water Drops Grown On Rural Cloud Nuclei, Abbas M. Sinnarwalla

Doctoral Dissertations

"Values of condensation coefficient, ß, were experimentally determined for water drops grown on cloud nuclei in atmospheric air samples. The measured quantities were supersaturation, final drop size (6 to 7.5 µm radius), and time to grow from near dry radius to final radius. The drops were grown in a vertical-flow thermal diffusion chamber, at supersaturations near 0.5 and 1.0%. The final drop sizes were large enough so that ß did not depend upon the size of the nucleus producing a given drop. The average value of ß was 0.025 with a standard deviation of about 0.01"--Abstract, page 2.

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 …

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 …

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 …

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 …

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 …

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.