Digital Commons Network^™

Distributed-Network Realizations For The Simulation Of Partial Differential Equations, Roy Dale Hensley

Doctoral Dissertations

"A method is developed for the simulation of the partial differential equation

-u_xx + k_ou_tt + k_lu_t +k₂u = g(t)

for various boundary conditions. The boundary conditions are used to classify the problems into types and the Laplace transformed solution of the most general problem of each type is obtained.

Synthesis techniques are presented for the realization of circuits containing distributed networks that can be used to simulate the partial differential equation for given boundary conditions. Several heat flow and vibrating string examples are included to illustrate the application of the …

Digital Spectrum Analyzer Systems: A Model And System Implementation, Richard Ray Kuenzer

Doctoral Dissertations

"This thesis introduces digital spectrum analyzer systems and presents a generalized model which can be used to implement new systems. The model is presented using the Digital Design Language (DDL) to facilitate system programming. Three hardware systems are defined and their merits are considered. Procedures are given to aid in implementing an analyzer system on a wide range of hardware configurations. A digital spectrum analyzer system which was implemented at the University of Missouri - Rolla and is presently being used by electrical engineering students is presented. This system utilizes the IBM 360/SO computer located in the Computer Center at …

Mass Transfer With Second-Order Chemical Reaction Inside Circulating Fluid Droplets, Roy James Brunson

Doctoral Dissertations

"The solution of a mathematical model is presented which describes mass transfer accompanied by a second-order chemical reaction inside a circulating, fluid sphere for the laminar flow region. The values for eight different mass transfer indices are presented as a function of the Peclet number, reaction number, diffusivity ratio, concentration ratio, and the dimensionless contact time. The results of this work are compared with the film and penetration theories for mass transfer with reaction as modified to apply inside a fluid sphere. This work corrects the three factors which limit the accuracy of applying previous theories to fluid spheres: geometrical …

Grain Boundary Diffusion In Ionic Crystals, Kulwant Singh Sabharwal

Doctoral Dissertations

"The diffusion of ¹³¹I in single crystals and along the tilt grain boundaries of pure and calcium chloride doped (142±5 ppm) bicrystals of sodium chloride, grown by Czochralski technique, was investigated using a microtome sectioning technique. Results on bulk diffusion in pure NaCl agree well with the results of earlier investigators and are represented by the D=(504 cm²/sec)exp (-2.27 ev/kT). Enhanced diffusion of ¹³¹I is observed along the grain boundaries and the presence of the dopant lowers the grain boundary diffusivity over the entire temperature range of 430ºC - 570ºC studied in the present investigation. Thermal activation and electrical polarization …

A Learning Receiver For Communication In Three-Component Multipath Channels, Richard Paul Brueggemann

Doctoral Dissertations

"An adaptive receiver is designed for transmissions through a time-varying multipath channel which may include both specular and diffuse components. The design is based on the theory of unsupervised learning machines and the receiver is a recursive structure which does not grow in complexity with each new observation, but is Bayes' optimal at each instant of time. The multipath medium is modelled as an aggregate of L conditionally independent transmission paths, each consisting of random and/or fixed reflections, and is identified in terms of three components: (1) indirect diffuse scatter, (2) indirect specular reflection, and (3) direct transmission. The channel …

Iicads--Integrated Interactive Computer Aided Design System, Archie Golden Lambert

Doctoral Dissertations

"This research has three goals. The first goal is to develop a software interface (supervisor) to support and control a variety of interactive subsystem modules; thus eliminating manual scheduling of interactive jobs. The second goal is to develop a common methodology for interactive subsystem design. The third goal is to develop a linear systems analysis package using the facilities developed under the first two goals. A software interface (supervisor) to support and control a variety of interactive subsystem modules is described. The supervisor operates under the constraints of a large multiprogramming variable task operating system as opposed to a time …

The Electrochemical Reduction Of Fumaric Acid On Hg-Bi Cathodes, Chen Hwei Chi

Doctoral Dissertations

"The electrochemical reduction of fumaric acid was studied on Hg, Hg/1%Bi amalgam, and Bi at 60ºC in acidic solutions of various pH ranging from 0.3 to 3.7. The fumaric acid was reduced to succinic acid with high efficiency on each electrode. The steady state kinetic parameters included Tafel slopes of ca. 2.3 RT/F and first order concentration dependences for both undissociated fumaric acid and H⁺. Transient measurements indicated low coverages of adsorbed fumaric acid and no adsorbed hydrogen species in the potential region of the reaction. A reaction mechanism is proposed which involves a chemical rate determining step between an …

A Study Of The Solid Regions In The System Zr-Te, Frances Dolores Jenkins

Doctoral Dissertations

"Relative intensity measurements of X-ray powder diffraction lines were made of compositions in the region ZrTe₀.₅ to ZrTe₂.₀, fired between 600º and 817ºC in evacuated sealed tubes. The experimental relative intensities of samples between ZrTe and ZrTe₂ were compared with values calculated for several theoretical models with different Zr vacancy ordering schemes and Te vacancy concentrations. The most probable structural model for compositions in the range ZrTe to ZrTe₁.₅ is one in which the number of Zr vacancies located at z = 0 ranges from 0% to 30%, with the concentration of Te vacancies ranging from 0 to 35%. A …

Probabilistic Models For Construction Estimating And Bidding, James E. Spooner

Doctoral Dissertations

"Two probabilistic models are offered as a means for quantitatively determining contingency in a lump-sum bid. The first model is based on the isolated project and requires subjective evaluation of probabilities associated with the individual elements of the estimate. Contingency is defined as a function of the standard deviation of project field costs. Procedures are developed to obtain the variance of the total field cost from three-value estimates of the primary quantities. The second model considers the business as a stochastic process with an initial risk reserve and a positive risk loading, and contingency in this model is a function …

A Yield And Fracture Model For Ti-6al-4v Titanium And 7075-T6 Aluminum, Richard L. Pendleton

Doctoral Dissertations

"The objective of the research being reported in this thesis was to conduct a series of experiments on two commonly used structural metals in several different environmental pressures so that a graphical representation of the material response both to yielding and fracture could be ascertained. It was further intended to show that parameters herein defined and called effective stress, effective strain, and pressure are useful parameters for graphically representing the material response. The final goal of this research was to show that the graphical representation does, in fact, predict the yield and fracture for a simple forming process. The forming …

The Average Dissipation Curve Of An Attenuative Layered Earth Medium, Joong Hee Chun

Doctoral Dissertations

"A feasible method of estimating the attenuative properties of a layered earth medium from a reflection seismogram has been developed. An average attenuation factor of n layers in the least squares sense is designated as ß and its usefulness in real applications is investigated. Techniques of extracting dissipation factors from both noise free and noisy reflection seismic traces are discussed. In order to describe the change of the factors with an increase of depth, an average dissipation curve the form of which is similar to the average velocity of layered medium is also introduced. Both the ß and the average …

Secondary Techniques For Increasing Fault Coverage Of Fault Detection Test Sequences For Asynchronous Sequential Networks, Lewis Ronald Hoover

Doctoral Dissertations

"The generation of fault detection sequences for asynchronous sequential networks is considered here. Several techniques exist for the generation of fault detection sequences on combinational and clocked sequential networks. Although these techniques provide closed solutions for combinational and clocked networks, they meet with much less success when used as strategies on asynchronous networks. It is presently assumed that the general asynchronous problem defies closed solution. For this reason, a secondary procedure is presented here to facilitate increased fault coverage by a given fault detection test sequence. This procedure is successful on all types of logic networks but is, perhaps, most …

Synthesis And Characterization Of Poly-(P-Phenylene Pyromellitamic Acid), Constantine William Tsimpris

Doctoral Dissertations

"Poly-(p-phenylenepyromellitamic acid)s have been synthesized over the weight average molecular weight range from 8,000 to 22,000 by reaction of pyromellitic dianhydride and p-phenylenediamine in dimethylformamide. The polymers were recovered as amorphous yellow powders having planar dimensions of 3-4 x 1-2 µm with thicknesses of 0.1-0.2 µm and contained 20-30% associated dimethylformamide. Consumption of reactants and attainment of the ultimate molecular weight of the polymer was found to occur within one minute. Thermogravimetry of the solid poly(amic acid)s was used in a method developed to determine the amount of associated dimethylformamide, to study the cyclization of poly(amic acid) to polyimide, and …

The Structural Behavior Of Cold-Formed Steel Members With Perforated Elements, Charles S. Davis

Doctoral Dissertations

"Analytical and experimental investigations have been conducted to study the influence of perforations on the structural behavior of cold-formed steel structural members. Since in many cases, the load-carrying capacity of cold-formed steel members depends on the buckling behavior of individual component elements, emphasis has been concentrated on the study of the instability and post-buckling strength of perforated elements. In this investigation, the buckling loads and post-buckling strength of stiffened and unstiffened compression elements having single circular and square holes have been studied analytically by using the finite element method. The effects of different holes on the buckling coefficient have been …

Computer Assisted Teaching Of Steel Design, Wendelin Henry Mueller Iii

Doctoral Dissertations

"A method for use in creating a university level course is presented. The specifics of each of the steps is given in general terms to allow its application to as many different topics as possible. This method is then specifically applied in the formation of a fundamental steel design course using the American Institute of Steel Construction Specification. The reasoning utilized in each phase of development is documented. A lecture style presentation complemented by a series of student oriented computer programs was chosen for use. The details of the course material in outline form is given along with the computer …

Synthesis And Properties Of Cadmium Manganese Ferrites, B. W. Jong

Doctoral Dissertations

"The formation sequence of (Cd,Mn,Fe) (Mn,Fe)₂O₄ from the individual oxides,x CdO + (1-x) MnCO₃ + α-Fe₂O₃,was found by X-Ray diffraction. Cd(Mn,Fe)₂O₄ was formed completely from CdO·Fe₂O₃ and CdO·Fe₂O₄ at 900°C and reacted with MnFe₂O₄ for 0 < x < 0.5 and with α-Fe₂O₃ for 0.5 < x < 1.0 to form a single phase of (Cd,Mn,Fe) (Mn,Fe)₂O₄ at 1150°C. This is the first time that the details involved in the formation sequence of CdMn-ferrite have been shown. A mixture of 0.5 CdO + 0.5 MnCO₃ + α-Fe₂O₃ was calcined at 900°C for 2 hrs forming Cd(Mn,Fe)₂O₄ with no Cd present in the other phases. Sintering was accomplished at 1150°C for 30 minutes forming a single phase of Cd₀.₅Mn₀.₅Fe₂O₄ with a bulk sintered density of 98-99% of the X-Ray density. The rate of changing density followed the relationship, p = K ln t + c, at temperatures between 1050°C and 1300°C. Magnetic properties of CdₓMn₁₋ₓFe₂O₄ were affected by composition x. A relationship, B = gx + h, was found between maximum magnetic flux density B and composition x at room temperature for 0 <̲ x <̲ 0.3. This was rationalized by a modification of Néel's theory. The maximum magnetic flux density decreased with increasing cadmium concentration for 0.3 < x <̲ 0.5. This decrease was attributed to the changing direction of the magnetic moment in the octahedral site sub-lattice according to the superexchange theory. No magnetic properties were observed due to the formation of a compensated antiferromagnetic phase for 0.5 < x <̲ 1.0. Maximum magnetic flux density increased with bulk density, while the coercive force decreased with the grain growth and the initial permeability increased with the bulk density and grain size. A stator core used for a-c electric motor application was formed by pre-sintering at 900⁰C for 2 hrs. Slots were then sawed with a tungsten carbide blade and final sintering was accomplished at 1150⁰C for 1 hr"--Abstract, pages iii-iv.

Methods And Applications Of Systems Identification, Allen Glenn Behring

Doctoral Dissertations

"A "Schmidt filter" is proposed to compute an optimal orthonormal basis for a set of "noisy" filter input functions. Procedures for determining the transfer function and inverse transfer function of the filter are given. The Schmidt filter is applied to the problem of determining mathematical models of discrete, stationary, linear, dynamic systems for the case where measurements may be corrupted by noise of unknown statistics. The identification problem is reconsidered for the case where noise and signal moments are specified. Procedures are given which insure unbiased, adaptive estimates of system order and parameters for this case. These theoretical propositions are …

Hydro-Thermal Generation Unit Commitment And Dispatch Using A Dynamic Programming Approach, Warren Dean Graham

Doctoral Dissertations

"The problem of thermal unit commitment is solved with dynamic programming. A practical example is given which solves the problem for a six generator system over a one year time span. This long range solution is used with a hydro optimization procedure to give an optimized hydro-thermal unit commitment solution. From this, a worth of hydro value is computed for each month, which may be used in the daily dispatching of thermal units and hydro. Applications of the program are also shown for aiding in generator maintenance scheduling and evaluating purchase power contracts with neighboring utilities. Error analysis is made …

Effects Of Cr-Plating And Environment On The Cracking Of Low Alloy Steels At High Temperatures, Robert C. Tooke

Doctoral Dissertations

"The cracking of low alloy Cr-Mo-V steels under cyclic stress at 1000-1100°C. was studied using a specially designed test apparatus. The results obtained from specimens plated with hard chromium are compared to those of unplated specimens. Tests conducted in gas mixtures of carbon monoxide and carbon dioxide showed that a high CO/CO₂ ratio retards cracking in both plated and unplated specimens. Both external and internal oxidation are used to explain these results. Inherent microcracks in the hard chromium plating promoted cracking in all CO/CO₂ environments. It was also found that these steels are severely embrittled in the presence …

An Experimental Investigation Of The Effects Of Ambient And Heated Steady Flow And Intense Sound Levels On The Response Of Acoustic Filter Elements, Raymond H. Schaffart

Doctoral Dissertations

"The primary purpose of this research was to investigate the effects of flow and finite amplitude waves on the response of acoustic elements. A further purpose was to evaluate the effects of elevated temperatures and cross-sectional dimensions on element performance. As an integral part of this work various laboratory techniques were explored for their suitability.

Empirical models for the acoustic impedance of side branch resonators were developed for the two operational modes, i.e., flow past the resonator and finite amplitude wave inputs. A description of the complex variation of the acoustic resistance of the resonator with flow past and variable …

Force Analysis Of Involute Spur Gears, Janakkumar Girjashanker Dave

Masters Theses

"This study is devoted to the fundamental action which occurs between spur gears with involute tooth profiles when power is transmitted at a constant angular velocity ratio. Various aspects of the interaction between two mating teeth are considered. Analytic expressions for the variation of the force transmitted between two teeth are derived. Two cases are considered which include and exclude the effects of sliding friction between the teeth. The parametric equations of the involute curves for two mating teeth are derived in terms of body-fixed coordinates. Analytical expressions for Hertz compressive stresses in the teeth were also obtained. The same …

Preliminary Studies With A Variable Transfer Composite Polymer Membrane., Samuel Walter Dortch

Masters Theses

"A preliminary study was done to determine the feasibility of using a compressed fibrous teflon (PTFE) silicone polymer membrane in extracorporeal oxygenation devices. A series of composite membranes were fabricated, using different concentrations of a dimethyl silicone polymer dissolved in petroleum ether, to give membranes having variable oxygen transfer properties. A gas-gas system was chosen to obtain the necessary transfer data. Data were obtained by transferring pure oxygen through the membranes into a mixture of 47 mole percent oxygen and 53 mole percent carbon dioxide. All analyses were obtained by chromatographic techniques. The results of these experiments show that membranes …

An Accurate Digital Instrument To Measure Reactor Period, Ernest Wayne Scott

Masters Theses

"At facilities having a research-training reactor, such as the University of Missouri-Rolla Reactor (UMRR), one finds it necessary to perform a large number of rod calibrations during the course of the year. In practice rod worths are determined by measuring the reactor period created by an incremental withdrawal of the rod under calibration. Period is then related to reactivity thru the use of a publication such as the AEC publication, TID-4500.

This frequent measurement of period makes it desirable to have a simple, automatic and accurate method to make such measurements. At UMRR we have designed, constructed and installed such …

Analysis And Measurement Of A Zener Diode Voltage-Reference, Armond C. Maxeiner

Masters Theses

"Output voltage sensitivity equations are derived for a zener voltage-reference circuit. The circuit consists of a DC-DC converter, a voltage-resistor current generator, and a zener diode. The performance of the voltage-reference is calculated using the sensitivity equations and compared to measurement data taken from a laboratory model of the circuit. The results are in reasonable agreement.

It was concluded that with careful selection of components, two of three major sources of error can be predicted and controlled; these are changes due to input voltage and changes due to temperature. The third, changes due to time, requires calibration against a voltage …

An Experimental Study Of Power Systems, Nguyen Quang Duoc

Masters Theses

"For three phase AC power systems consisting of synchronous machines interconnected by transmission lines and other electrical transmission equipment, the power transmitted and the stability of the system depend upon the constants of synchronous machine and the characteristics of the transmission lines. The purpose of this work is to design and set up a model of a power system in the laboratory, measure the constants of synchronous machines, the power angles and power flows of the system. An investigation of the effects of the saturated machines is based upon the laboratory data.

This work is intended primarily as a tool …

Design Of A Digital Control Unit For A Seismic Digital Tape System, Cao-Van Chung

Masters Theses

"This paper describes the interface between the NOVA digital computer and the Texas Instrument tape unit which handles field data recorded simultaneously from a maximum of 31 channels. The interface is the means through which the NOVA computer can control the tape unit and recover data. To provide necessary background information a review of the characteristics of the tape unit and the input-output operation of the NOVA computer are given. As the first part of the design, the general interface design is presented and the functions of its units are described. After discussion of functional assignment of each unit, coordination …

A Sensitive Temperature Measuring System, Larry Dean Morris

Masters Theses

"A sensitive temperature measuring system, providing an analog output proportional to sensor temperature, has been designed for use in the wall temperature control system of a cloud simulation chamber. A platinum resistance element is the sensor, and a precision wirewound resistor is the reference in a bridge circuit which uses four low cost operational amplifiers arranged to provide two precision 1000 Hz current sources. Problems with an initial bridge amplifier design were corrected in the final design by the use of a low Q bandpass amplifier for the bridge signal followed by a phase detector and an output low pass …

High Speed Magnetically Supported Vehicles For Reducing Transportation's Degradations Of The Environment, Pravinchandra Shukla

Masters Theses

"The development of new techniques for higher speed transportation is desirable to satisfy the environmental, conservation, and economic requirements of society. Some of the important factors are presented for developing magnetically supported vehicles. A new method for improving the ratio of lift force to drag force is suggested and discussed. An application of the new technique to vehicles that would ride on a carpet of magnetism and would operate with less waste of energy is suggested "--Abstract, page ii.

A Study Of Plane Wave Filter Analysis With Flow, Thomas Valle Huber

Masters Theses

"The purpose of this investigation is to determine the effect of slow steady flow on the reflection and transmission characteristics of acoustic filters.

A standing wave tube and transmission tube apparatus, designed and built by a previous investigator, was modified to accept slow steady flow. Reflection characteristics were determined from measurements made on the inlet side of the filters investigated. These data along with measurements taken with the transmission tube apparatus were used to determine transmission characteristics. The calculations were simplified by terminating the filters anechoically. The filters used in this investigation were an expansion chamber, an automobile type muffler …

Digital Registration Of Stereo Images Using The Fast Fourier Transform, Victor Francis Wilreker Jr.

Masters Theses

"The exact alignment of multispectral imagery is a requirement of any image classification system. This investigation develops a system of programs which result in a technique that corrects for the translational and rotational misalignment of two images. Rotational and translational components are determined by using the fast Fourier transform to find the points of maximum correlation between the two images. The registration of two equal but misaligned boxes is given as an example of how the transform technique is used in correlating the images. The results of registering two digitized images that were obtained by scanning a pair of color …