Engineering Commons^™

Investigation And Optimum Design Of The Generalized Second-Order Phase-Locked Loop, William Allen Novick

Dissertations

In this dissertation, a second-order phase-locked loop (PLL) in which the loop filter contains complex zeros is investigated in both its linear and nonlinear modes of operation; prior designs used a filter containing a simple zero on the negative real axis. This "generalized" second-order PLL had been heretofore essentially unexplored.

The basic characteristics of the generalized second-order PLL operating in the linear mode including the open and closed-loop responses and the corresponding root locus were generated and compared against those of the conventional second-order PLL. As in the conventional case, the generalized second-order PLL is found to be unconditionally stable. …

Preparation And Magnetic Properties Of Rare Earth Garnets And Apatites, Rostam Mondegarian

Dissertations

It has been found possible to prepare garnets with magnetic trivalent rare earth ions filling all or most dodecahedral sites while nonmagnetic Sc³⁺ ions fill all octahedral sites and magnetic Fe³⁺ ions fill all or most tetrahedral sites. Phase-pure garnets found include {RE_3-ySc_y}[Sc₂](Fe₃)O₁₂, where RE is Sm, Eu, Gd, Tb or Dy and y can be zero with Sm and Eu; {Nd₃}[Sc₂](Fe_zGa_3-z)O₁₂; and other Nd-Sc-Fe garnets of the type {Nd_3-(w+y)M_wS_cy}[Sc₂](Fe …

Separations Of Multicomponent Mixtures Via Thermal Parametric Pumping, John Daniel Stokes

Dissertations

This dissertation covers the separation of solutes from multicomponent solutions via direct mode thermal parametric pumping.

Dilute solution separations were predicted from existing binary equations by assuming the existence of pseudo binary systems, each system consisting of one solute and the common solvent. Two systems, toluene-aniline-n-heptane and toluene-acetophenone-n-heptane with a silica gel adsorbent were used to experimentally demonstrate the separation. Experimental results were in good agreement with the mathematical predictions.

For concentrated multicomponent solutions, the separation was demonstrated by the system, toluene-acetophenone-n-heptane on silica gel. The effects of mass transfer and nonlinear adsorption isotherms became significant and a numerical solution …

An Analysis Of The Passenger Vehicle Interface Of Street Transit Systems With Applications To Design Optimization, Walter H. Kraft

Dissertations

This research analyzes the Passenger Vehicle Interface of the street transit systems and presents applications for design optimization. The Passenger Vehicle Interface (PVI) is defined as the interaction between the passenger and vehicle elements of the street transit system.

Human observer and photographic studies were conducted in 17 cities in the United States and Canada to measure the time for queues of passengers to board various transit vehicles. The data were analyzed by considering seven factors that affect the Passenger Vehicle Interface: Human Factor, Modal Factor, Operating Practices, Operating Policies, Mobility, Climate and Weather, and Other System Elements. Those effects …

Deposition Of Suspensions In Laminar Flow In The Entrance Region Ofa Channel And In A Diffuser, Shawki Mahmoud Eldighidy

Dissertations

In this investigation, the deposition of suspensions in laminar flow in the entrance region of a channel and a diffuser was considered.

The particulate phase was considered to he under the action of the electric field force clue to electrostatic charges. In addition, a lift force acting on each particle at the wall arising from the fluid shear near the wall and an adhesive force between each particle and the wall due to the difference of the material properties for both particle and walls were considered as surface forces.

The suspension flow was assumed to be incompressible, laminar, dilute, and …

An Investigation Of The Optical Absorption Properties Of Silicon As Related To Its Electrical Conductivity, Onofrio Louis Russo

Dissertations

The purpose of this study is to demonstrate the feasibility of obtaining the electrical conductivity of band gap semiconductors, by considering the absorption of radiation in the visible region. The experimental evidence confirmed predictions that the conductivities of the silicon samples are related to the horizontal displacement of energy in the absorption curves. The material used in this study was p-doped silicon, although the approach should be valid in general for either elemental or compound semiconductors.

The absorption coefficient for silicon was measured in the radiation region between 2.0 and 3.0 ev. This region above the indirect band gap (= …

Optimal Control And Identification Of Stochastic Systems Using Differential Game Theory, Harry Marvin Burbank

Dissertations

This dissertation deals with linear systems subjected to stochastic disturbances. The class of stochastic processes considered is the class of second order stochastic processes characterized by having finite continuous covariance. The properties of the covariance provide means to formulate optimization problems without the difficulties present when the covariance is not finite or continuous.

The first aspect studied was several classes of optimal control problems. The effects of the stochastic processes were approximated by the effects of its first two moments. This procedure resulted in allowing optimal system controls to be found whatever the first two moments of the stochastic input …

Design And Analysis Of An Instrument System For Rheological Testing Of Whole Blood Samples, Robert Rimvydas Sinusas

Dissertations

The dissertation covers the conceptual design of a rheometer for testing whole blood samples through to the clotting state. While the design aims at increased measurement accuracy, the design employs well known technologies and available components.

The main reason for preoccupation with blood testing is that recent investigations have indicated that physiological disorders can be correlated with rheological properties of blood. The pursuit of an improved means of correlation is initiated with a survey of the rheological properties of blood. The relevance of these blood properties is then discussed. From this discussion a broader blood model is developed as a …

Characterization Of Thixotropic Materials And Modification Of The Weissenberg Rheogoniometer, Paul Joseph Orosz

Dissertations

A Weissenberg Rheogoniometer, Model R-18, was modified to give complete rheological curves without resetting the gearbox and generate hysteresis loops for time-dependent, non-Newtonian materials. This modified instrument was used to analyze a number of materials. Standard Newtonian and known time-independent, non-Newtonian materials were studied to insure the accuracy of the instrument. Results indicated that the instrument would reproduce known viscosities of these materials, give consistent results, and not display inherent hysteresis loops with non-thixotropic materials. Materials known and suspected to be thixotropic: silicone grease-oil mixture, montmorillonite clay, and blood were tested. All displayed the characteristic hysteresis loop usually associated with …

The Interpretation Of Infrared And Raman Spectra Using Pattern Recognition, John Martin Comerford

Dissertations

An automatic classification of chemical compounds by computer processing of digitized spectral data is presented. The classification system is based on a branch of artificial intelligence known as supervised learning, and used binary linear classifiers to identify compounds as alcohols, esters, ethers, ketones or compounds containing double bonds.

Each of the 1117 spectra in volume one of Sadtler's Standard Raman Spectra was coded using a scale from 0 to 9 in the range from 4000 to 200 cm^-1. One hundred and twelve readings were taken on each spectrum. These data were then examined using pattern recognition techniques, and …

The Theory Of Multiple Measurements Techniques In Distributed Parameter Systems, Babajimi Claudius Okunseinde

Dissertations

A comprehensive theory of multiple measurements for the optimum on-line state estimation and parameter identification in a class of noisy, dynamic distributed systems, is developed in this study. Often in practical monitoring and control problems, accurate measurements of a critical variable are not available in a desired form or at a desired sampling rate. Rather, noisy independent measurements of related forms of the variable may be available at different sampling rates. Multiple measurements theory thus involves the optimum weighting and combination of different types of available measurements. One of the contributions of this work is the development of a unique …

Synthetically-Generated Holographic Memory System Utilizing Partially Coherent Light, William A. Barrett

Dissertations

This dissertation proposes a novel form of optical ROM for the digital computer. This memory makes use of holographic techniques because of the advantages offered by holographic memories over conventional optical ones, especially with regard to dust and scratch sensitivity.

These advantages have long been recognized by workers in the field, indeed several holographic optical memories have already been proposed.

A survey of the state of the art of digital computer memories is offered in the introductory part of the thesis. Particular emphasis is placed on optical memories. A brief review of basic holographic theory is also included for reference. …

A Nonlinear Viscoelastic Model, Yon-Li Shangkuan

Dissertations

A nonlinear viscoelastic model has been developed to describe the non-Newtonian viscosities and the primary normal stress differences of high polymers at steady-state shearing flow.

It has been demonstrated that the Huang-Shangkuan model gives the best representation of the experimental data for a wide range of shear rates. In the high shear rate region the Huang-Shangkuan model is distinguished among other models by its capability to predict the nonNewtonian viscosities and the primary normal stress differences Which the other models fail to predict.

Continuum mechanics, Lodge's network theory and Rouse's theory provide specific information in developing our model. The theoretical …

Optimal Planning Of Fixed Route Bus Transit Systems : A Systems Approach, Young Lee

Dissertations

A new bus transit planning tool is developed for application in determining operating policies of a fixed-route bus transit system. The objective of the study is to model a bus transit system which functions under time-varying passenger demands and service characteristics.

The two phase transit model developed in this research is intended for use as a mass transit planning tool, to solve transit problems confronting the mass transit planner. The model is used to compute cost differentials in transit system options. These alternatives of expanding, abandoning or modifying service depend upon the service frequency, fleet size and other system attributes …

Effect Of Gas Temperature Gradients And Radiant Heat Transmission On Kinetic Model Behavior, Richard W. J. Robertson

Dissertations

Satisfactory methods to predict radiant heat transmission in enclosures containing a radiating gas at uniform temperature are available. These methods have been traditionally used in solutions of kinetic models.

Kinetic models are strongly temperature dependent with a difference of 10°K able to double the reaction rate. In the present investigation, calculation techniques which make allowance for the non-uniformity of gas temperatures in an enclosure are applied to the kinetic models. The furnace problem considers only the radiation section with the assumption that detailed knowledge of combustion and fluid flow pattern within the enclosure is available.

If the gas space in …

Dynamics Of Interconnected Systems With Pulse Frequency Modulators, Halil Ozcan Gulcur

Dissertations

The objective of this dissertation is to study the dynamics of systems consisting of interconnections of an arbitrary number of complete-reset pulse frequency modulators (CRPFM's) and linear dynamical subsystems (in general, time-varying, lumped and/or distributed). CRPFM, which represents a generalization of several types of pulse frequency modulators (PFM's), consists of two basic components; a multi-input dynamic element, called the timing-filter (TF) and a threshold device (TD). Whenever the output of the TF reaches a given threshold value the TD generates an impulse and, at the same time, resets all the states of the TF to zero. This dissertation is devoted …

Adaptive, Differential Pulse-Code Modulation For Speech Processing, Peter Cummiskey

Dissertations

The objective of the research reported here is the design of efficient speech coders that can easily be implemented in integrated circuit hardware. Companding techniques like those introduced by M. R. Winkler, J. A. Greefkes, F. DeJager, A. Tomozawa and H. Kaneko were explored along with a large body of theory concerning the application of linear prediction to speech coding.

The best features of the speech signal to be measured and coded are the overall amplitude, the resonant frequencies and dampings of the vocal cavity and the fundamental frequency of the vocal cord oscillations. Adaptive quantization was used to track …

A Simulation Modeling Approach To Central City Dynamics, Leonard William Schaper Jr.

Dissertations

This dissertation describes a computer simulation model of a central city with emphasis on its application to Newark, New Jersey. The work begins with a review of the Forrester Urban Dynamics Model; the first attempt to simulate the entire system of the city. The objections to this model which have appeared in the literature are discussed, and the model is viewed in the light of other work in the field. A set of guidelines to aid the "second generation" model building effort is developed. The actual construction of a model which attempts to follow these guidelines is described. First, the …

Representation And Characterization Of Thixotropic Fluids, Huei-Hsiung Wang

Dissertations

Thixotropy is a time-dependent rheological behavior of a group of fluids which are characterized by an isothermal reversible breakdown induced by a mechanical disturbance. Based on this definition, a mathematical model of reversible degradation kinetics is set up. Its development leads to two equations which represent quantitatively the hysteresis loop and torque-decay curve. These equations consist of five independent parameters with their physical meanings. These parameters can be used to characterize the properties of thixotropic materials.

The original Weissenberg Rheogoniometer was modified to measure the thixotropic behavior of blood with the step change and the ramboid change of shear rate. …

The Effect Of Ultrasonic Vibrations On Heterogeneous Catalysis, William Lintner

Dissertations

The effect of ultrasonic vibrations on the vapor phase decomposition of cumene to benzene and propylene was investigated employing silica-aluminum cracking catalyst.

The catalytic reactor consisted of a 1 cm. diameter stainless steel tube containing a 20 in. long preheater and a 4 in. long catalyst chamber. The catalyst bed was irradiated from above by means of an ultrasonic horn which transmitted acoustical energy directly into the vapor.

The reactor was run at temperatures of 650°F. and 1050°F., frequencies of 26,000 cps and 39,000 cps, feed rates of 20 to 600 gms./hr., power outputs of 0.5 to 1.3 watts/cm.^{2 …}

The Preparation Of Cis- And Trans-1,2-Dimethoxyethylene. The Study Of The Cis-Trans-Rearrangement And Evaluation Of Equilibrium Constants, James T. Waldron

Dissertations

Equilibrium constants for the mercuric acetate-catalyzed reaction, cis-CH₃ OCH=CHOCH₃ D trans-CH₃ OCH=CHOCH₃, have been determined in the liquid and vapor phase over the temperature range 30° - 175°C by gas chromatography analysis. A novel synthesis of the cis- and trans-isomers of 1,2-dimethoxyethylene is discussed. From a screening of 29 catalysts, mercuric acetate, mercuric benzoate, and mercuric salicylate were found to be favorable isomerization catalysts. For the liquid phase reaction,

ln K = -779.8/T + 0.6748

with ΔH° = +1.549 ± 0.019 Kcal/mole
and ΔS° = +1.34 ± 0.05 e.u./mole

Similarly, for the vapor phase reaction, …

Structure And Magnetic Properties Of Rare Earth Garnets, Milan R. Kokta

Dissertations

This study deals with preparation and magnetic properties of garnet compounds containing rare earth ions and scandium ions on two crystallographic sites: the dodecahedral and the octahedral. A number of compounds of the types {R_3-yr_y}[r_x Ga_2-x](Ga₃) O_12' {R₃}[Sc₂](Fe_z Ga_3-x) O_12' {R_3-y Sc_y}[Sc₂] (Fe₃) O_12' and {R_3-y r_y)[r₂ (Fe_z Ga_3-z) O_12' where R stands for large rare earth ions such as Nd³⁺ and Pr³⁺, …

Electromagnetic Wave Propagation In Nonuniform Waveguides With Perfect Conducting Walls, Irwin Share

Dissertations

The analysis of nonuniform waveguides is formulated in terms of non-orthogonal generalized coordinates by utilizing the Hertz vector potentials and the Riemann metric tensor.

When the Hertz potential is expressible as a function of the propagation coordinate times a function of the transverse coordinates, then the nonuniform waveguide may be represented by transverse equations and a set of uncoupled nonuniform transmission lines. This decomposition facilitates studying propagation along the propagation coordinate. Sufficient conditions to achieve this decomposition are investigated. It is demonstrated that these constraints may provide guidelines for selecting a useful coordinate system to describe the nonuniform waveguide. In …

An Investigation Of The Neuromuscular Command In The Control Of Respiration, Nirmal Kumar Mishra

Dissertations

The purpose of the investigation is to study the signals involved in the respiratory system and to obtain a model for the dynamics including the activity of the phrenic nerve as the input and the transpulmonary pressure, air flow and the volume as the response.

Experiments were done on anasthetized dogs under natural breathing, with steady state response to various levels of CO2 in the inspired air, and under electrophrenic stimulation. Bipolar electrodes were used at the phrenic nerve, in the cervical region, either for recording the phrenic neurogram or for supramaximal unilateral (or bilateral) stimulation using pulse frequency modulated …

Methods For Acoustic Holography And Acoustic Measurements, Wolfgang Fischer

Dissertations

In this dissertation, a novel "four-step acoustical holographic imaging system" is described and several means for its implementation are analyzed both theoretically and experimentally. This system is compared with other methods of acoustical holography, (ie. permitting to obtain a visible, 3-D image of an object insonified with supersonic waves) and some of its advantages are indicated.

The use of optical holographic techniques to convert an arbitrary acoustic image to a visible image is investigated and a new method - the "holographic sound image converter" - is introduced and analyzed. This converter consists of the "holographic interferometer" and an appropriate "coupler". …

Vibration And Buckling Of Elastic Plates With Shear And Rotatory Inertia, Bomi Batiwalla

Dissertations

The effects of shear, rotatory inertia and inplane forces on the transverse vibration of thin plates are studied. In addition, the effect of shear on the buckling of thin plates is examined. A general differential equation of motion is derived for an isotropic thin plate subjected to normal and inplane forces with the consideration of shear and rotatory inertia. The method of internal constraints and Hamilton's principle are utilized.

The resulting fourth order differential equation is solved for simply supported plates of various shapes by employing a finite difference technique. The shapes examined are a square, a circle, a circular …

The Effect Of Variable Properties On The Laminar Flow Of Gases, Norman Shilling

Dissertations

The problem of heat transfer in laminar flow of a gas through a constant diameter cylindrical tube is treated. The gas is cooled by the tube walls held at constant temperature. Two tube inlet conditions are considered: (1) fully developed velocity and uniform temperature profiles (Graetz boundary condition) and (2) uniform velocity and temperature (UTV) profiles. Results of the theoretical and experimental phases of the work are presented.

The theoretical solution is based on the compressible boundary layer equations with varying transport and thermodynamic property terms retained. For the Graetz condition, an existing finite difference solution scheme is modified for …

The Oxidation Of Carbon Monoxide By Magnesium Aluminate, James A. Whelan

Dissertations

In this research the catalytic oxidation of carbon monoxide was investigated on magnesium aluminate catalysts, MgO:xAl₂O₃, with five different compositions, x, ranging from 1.0 to 3.0. The reaction was run at temperatures ranging from 500 to 600 °C. with radioactive carbon monoxide as the tracer. An experimental technique has been devised for the analysis of unreacted CO which takes into account a correction for the solubility of CO in CO₂.

Four mathematical models were postulated to explain the mechanism of reaction. The models were examined against experimental data by means of non-linear least squares …

Centering In Parallel Channel Systems, Allen Katz

Dissertations

Several types of signal processing systems in which the signal flows along parallel channels in a fashion similar to the auditory system have been investigated. The effect of excitation with signals containing both single and multiple spectral peaks (formants) was considered. In particular, the effect of nonlinear interaction between channels, referred to as centering, in the presence of noise was studied.

These systems were investigated for their value, both as information processing networks and as models of the auditory system.

The analysis indicates that parallel channel systems, in general, exhibit excellent performance in the presence of noise, and that a …

Sidelobe Suppression In Chirp Radar Systems, Stephen N. Honickman

Dissertations

Pulse radars extend target range detection by increasing the transmitted pulse width. On the other hand, target resolution is enhanced by reducing the system pulse width. These dichotomous requirements led to the invention of chirp radar systems which achieve greater target resolution for a given detectable range by frequency modulating the carrier frequency of the transmitted pulse. Along with the advent of chirp radars came the extremely simple and reliable technique of chirp signal generation known as "passive generation". However, one of the undesirable features of "passive generation" lies in the infinite time required for transmission of the resultant pulse, …