Engineering Commons^™

Further Development Of Preparation And Measurement Techniques For Triode-Sputtered Mercury Cadmium Telluride Thin Films, Tai-On Chan

Theses

The modified MRC 8800 R.F. triode sputtering system was used for mercury vapor sputtering (Hg^1-xCd^x)Te targets onto N-type (111) silicon substrates with a resistivity of 70 to 90 ohm-cm. Deposition rates were in the 2.6 to 3.6 A/sec range, A Hall mobility value, at 87°K, of 2550 Cm²/V•sec with a carrier concentration of 7(10¹⁵) cm^-3 was obtained for 9 μm thick films with an X-value of 0.25. Obtaining good sputtered films reliably was dependent on having targets that would not crack when bombarded with mercury ions. Improvements in the methods used …

Computer Analysis On Discontinuity Of Cylindrical Pressure Vessels With Various Heads, Ku-Shiang Sheu

Theses

This thesis uses FORTRAN programs to compute the maximum shear stresses of the cylindrical pressure vessel with various heads. They are cylindrical, spherical, ellipsoidal, flat and conic shapes. Also the maximum shear stresses for the bimetallic joints at the vessel wall and away from the vessel wall are analyzed. Numerical examples are given for each case to facilitate the applications.

Frequency Characterization Of A Thin Linear Antenna Using Diakoptic Theory, Howard Harold Smith

Theses

A frequency dependent analytical expression for the input impedance of a thin wire antenna is obtained using diakoptic theory. In diakoptic theory the linear antenna is seperated into electrically short segments where each segment is treated as a two-port network. This approach eliminates the need for an integral equation formulation. An impedance matrix is found which characterizes coupling between all segments. By expanding the free space Green's function in a power series in wavenumber k each entry in the resultant impedance matrix is obtained as a function of frequency. Enforcement of the continuity of currents and equality of scalar potentials …

Enhancement Of The Thermophysical Capability Of The Chemical Engineering Simulation System, Joydeep Banerjee

Theses

The CHESS (Chemical Engineering Emulation System) is a generalized steady-state, sequential-modular chemical process simulation program. In this thesis, the thermophysical data prediction capability of CHESS has been expanded by: incorporating more accurate thermodynamic phase-behavior models, by utilizing these models in generating a wider range of thermophysical properties, and providing an updated and expanded database for pure-component physical properties.

The overall performance of the simulation system's thermophysical package has been evaluated using the study of a subprocess consisting of various rotational equipment modules.

In this work, the Chao-Seader liquid phase activity coefficient model has been reinstalled in conjunction with the original …

A Study Of Parameters Indicating Microbial Activity In Mixed Aerobic Cultures, William Smith

Theses

Mixed liquor suspended solids (MLSS), oxygen uptake rate (OUR) and general dehydrogenase activity, as expressed by the reduction of the electron-acceptor Dye 3-(4',5'-dimethylthiazol-2-yl)-2, 4-diphenyltetra-zolium bromide (MTT), were compared for their ability to measure microbial activity in mixed aerobic cultures. A fourth parameter, specific enzyme activity, was dropped from consideration because of the difficulty of developing a satisfactory experimental technique. Measurement of the parameters was applied to the biodegradation of phenol and o-chlorophenol by activated sludge from a municipal sewage treatment plant, and by two commercially available bacterial preparations.

MLSS, although the most commonly used of the three parameters tested, is …

Laminar Flow Through A Porous Annulus With Surface Suction, Stelios C. Nicolaides

Theses

A theoretical investigation was conducted to obtain the velocity, pressure and shear stress distributions for incompressible, steady, fully developed, laminar flow through an annulus, with a uniformly porous inside tube wall. Suction at the walls is a result of the pressure difference across the porous wall.

The continuity equation, momentum equation and the Darcy's law for suction velocity are analysed with an integral method. The resulting differential equations were solved using a numerical technique.

For the same radii ratio, dimensionless inlet pressures on both sides of the porous wall and dimensionless porous resistance, the dimensionless length required to reach zero …

Present Reliability Of Liquid Crystal Display Devices, C. N. Suresh

Theses

The purpose of this Thesis is to study the life of liquid crystal display devices as at present available in the market place. To accomplish this, accelerated tempera-ture conditions at 77°C and 85°C were used.

During the last few years, there has grown a tremendous interest in wide range temperature operating and fast LCDs. It is therefore important to understand how LCDs behave under these conditions.

The reliability of a liquid crystal display is usually measured in terms of a quantative degradation in electrical performance and a degradation in visual appearance. The degradation in visual appear6knce may manifest itself as …

Analysis Of Bolted Rock By Computer Modeling, Niann-Chyun Wang

Theses

A computer model-based on VAX-ANSYS system was developed to model the behavior of multi-layer rock systems reinforced by pretensioned rock bolts. Three models were utilized for this study. The third model represents the friction between interlayers occuring due to the tensioned rock-bolts. Results obtained from this study compare favorably with those obtained from equations developed from model studies. An attempt has been made to study the effects of creep on the behavior of the rock-layer system.

The Effect Of Single Electrolytes On The Vapor-Liquid Equilibrium Of Mixed Solvents, Peggy Tomasula

Dissertations

A group-contribution model for the prediction of salt-effects on the vapor-liquid equilibria of multicomponent electrolytic solutions containing a single electrolyte is presented. Coulombic interactions are represented through a Pitzer term. Solvation effects and short-range interactions are represented through a UNIQUAC-type expression. An ion-size, a solvation and three ion-solvent interaction parameters per salt-solvent binary are required for multicomponent predictions.

All parameters are obtained only through the correlation of binary salt-solvent osmotic coefficient and vapor-pressure depression data at 25°C, in most cases, and binary solvent VLE data. The salt-solvent binary data were correlated with an average percent error in CD of 2.5 …

Ternary Ion Exchange In Fixed Beds : Equilibrium And Dynamics, David W. H. Roth

Dissertations

A model was developed to simulate ion exchange within fixed beds for ternary systems. Models of the fluid phase material balance, phase equilibria, and diffusion of ions through the film and within the resin phase incorporated the latest advances in ion exchange theory. The separate model elements were combined after testing into an overall general model. Non-linear regression support programs were developed to estimate equilibrium parameters and resin phase diffusion coefficients.

A computer program was developed to estimate axial dispersion coefficients from experimental data. General correlations derived from literature sources were tested, and axial dispersion terms were included in the …

Shear Induced Anisotropy In The Rheology Of Solids Dispersions, Nicholas G. Triantafillopoulos

Masters Theses

Under strong hydrodynamic forces, solids dispersions could no longer be considered isotropic fluid s but rather two-phase systems. The continuous (dispersing) phase was only sheared in side an effective gap determined in a Couette flow device by the presence of solid (dispersed) phase in to suspension. Three parameters, the effective gap, percent gap reduction and the relative shear volume, were incorporated to account for the influence of solids in the rheology of their suspension.

The objectives of this study were: (1) to investigate the role of solids volumetric concentration, particle size, nominal gap and continuous phase viscosity on Hercules Hi-Shear …

An Application Of A Heuristic Search Algorithm In Biomedical Images On The Magiscan Ii Image Analysis System, Patricia S. Humes

Masters Theses

The goal of this project was to successfully apply a heuristic search algorithm in the image analysis environment of the Magiscan II Image Analysis System. The purpose of this particular application was to enable the specific segmentation of a white blood cell image by outlining the boundary of the cell nucleus, a process not currently possible with the existing system software.

The method used involved tracing boundaries by choosing points based on a calculated cost factor. The cost factor has several input parameters that will enable it to be applied in a wide variety of applications. Several different cells' nuclei …

A Structural Study Of Some (H6-Arene)Ml2, First Row, Group Viii, Transition Metal Complexes And Their Derivatives, Stuart Kevin Janikowski

Theses and Dissertations

The structures of five organonickel compounds were determined using x-ray diffraction techniques. This study was conducted to ascertain the relationships between the compound's structures, bonding, and chemical properties. The first structural evidence for discrete complexes containing Ni-SiX3 bonds is (h6-mesitylene)Ni(SiCl3)2 and presented. The compounds (h6-toluene)Ni(SiF3)2, crystallize in space group P21/c with Z = 2. The lattice constants at 23° C are: a = 9.056(2), b = 14.426(1), c = 13. 3 0 3 ( 2) ~, {J = 10 0. 6 9 ( 1 )0 , and a = 11. 3 5 5 ( 3) , b = 11.268(4), c …

Analyses Of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena, Ajit Dhundiraj Kelkar

Mechanical & Aerospace Engineering Theses & Dissertations

Composite laminates have high strength to density ratios that make them attractive for use in aircraft structures. However, the damage tolerance of these materials is limited because they have very low ultimate strains, no plastic deformation range, and no usable strength in the thickness direction. These limitations are very obvious when laminates are subjected to impact loads. Due to these impact loads, laminates suffer visible and invisible damage. To improve the material performance in impact requires a better understanding of the deformation and damage mechanics under impact type loads.

In thin composite laminates, the first level of visible damage occurs …

Electronic Absorption Spectra Of Ni (Ii) In Sodium Phosphate And Sodium Fluorophosphate Glasses, Tarek Mostafa Sami Genena

Archived Theses and Dissertations

No abstract provided.

The Unification And Decomposition Of Processing Structures Using Lattice Theoretic Methods, David L. Livingston

Electrical & Computer Engineering Theses & Dissertations

The purpose of this dissertation is to demonstrate that lattice theoretic methods can be used to decompose and unify computational structures over a variety of processing systems. The unification arguments provide a better understanding of the intricacies of the development of processing system decomposition. Since abstract algebraic techniques are used, the decomposition process is systematized which makes it conducive to the use of computers as tools for decomposition. A general algorithm using the lattice theoretic method is developed to examine the structures and therefore decomposition properties of integer and polynomial rings. Two fundamental representations, the Sino-correspondence and the weighted radix …

Color Display Of Vowel Spectra As A Training Aid For The Deaf, Amir Jalali Jagharghi

Electrical & Computer Engineering Theses & Dissertations

The objective of this research was to develop a transformation for mapping speech parameters to color parameter. This transformation is done in real-time, and the resulting color parameter are continuously displayed on a color monitor. This visual speech display is to be used as a speech articulation training aid for the deaf. The conversion of speech acoustic signals into speech parameter was accomplished using special -purpose electronics. The real-time conversion of speech parameter to display parameter was controlled by an 8086/8088 microprocessor operating in an S-100 bus structure. The coefficients of the Karhunen-Loeve series expansion of speech power spectra were …

Analog Computer Simulation With Automatic Scaling By Digital Computer, Mark Anthony Motter

Electrical & Computer Engineering Theses & Dissertations

A computer-aided design approach for the simplification of analog computer simulation is presented. The simulation configuration consists of an EAI 2000 analog computer with serial communications link to a PDP — 11/24 digital computer. Under control of the PDP-11, the analog simulations are realized with appropriate time and magnitude scaling which adjusts the range of the simulation coefficients and prevents overloads of the analog components. The analog computer hardware configuration accommodates both stable plants up to eighth order and closed-loop systems up to tenth order. Cascade compensation is provided for the closed-loop systems.

The plant may be described by either …

Removing Fluoride From Drinking Water By Organic Polymers, Eleni Davou Achilleos

Civil & Environmental Engineering Theses & Dissertations

Fluoride is a substance that can provide beneficial or detrimental effects depending on the total amount ingested. Naturally occurring high fluoride concentrations exist in many drinking water supplies. The fluoride removal methods developed in the past have been found to be either impractical and/or not cost effective.

The purpose of this study was to determine whether organic polymers can effectively remove fluoride. The water used in this study contained naturally occurring fluoride concentrations between 4.5 to 5.5 mg/1 and it was collected from the City of Franklin, Virginia, water supply system. Laboratory jar test procedures, which simulated a conventional water …

Investigation Of Pre-Detection Signal Processing Of Pseudonoise Communication Signals In The Presence Of Additive White Gaussian Noise And Cw And Bursty Interference, Israel Mayk

Dissertations

By comparison to conventional communication systems, spread-spectrum systems are known to be less affected by interference because of their large dimensionality in signal space. Nevertheless, significant performance degradation is experienced when large interference exists in a few or even one signal coordinates. In this case, interference reduction techniques are also known to provide additional processing gain. A novel class of pseudonoise (PN) invariant algorithms is derived to reduce the impact of interference and restore much of the structure of PN signals received in the presence of interference and noise. A PN signal received by a pre-detection signal process (PDSP) implementing …

Deformation And Fracture Of Nodular And Grey Ferritic Cast Irons, Maha El Koshairi

Archived Theses and Dissertations

No abstract provided.

Kinetic Modeling Of A Laminar-Flow Reactor, Shih-Hsin Chang

Dissertations

The laminar-flow reactor considering radial dispersion for a species incurring first-order homogeneous (bulk) and heterogeneous (wall) chemical reactions was mathematically modeled. The equation was solved both analytically, and by the Crank-Nicolson finite-difference technique.

The response surface method was used to obtain the optimum values of the two rate constants. The optimum values interact because the wall and bulk reactions proceed in parallel. Varied reactor diameters serve to decouple the bulk and wall reactions to locate the true values of the rate constants.

Four dimensionless variables were defined and used to characterize the reacting system. In addition, their values were shown …

The Effect Of A Higher Order Pole On The Optimum Design Of Minimum Threshold Phase Locked Detectors, Bernard Zivotofsky

Dissertations

The phase lockedloop is widely used as an FM demodulator known as a phaselocked detector (PLD). It is particularly useful in the detection of weak signals because lower threshold is possible with a PLD than with a conventional limiter discriminator. An enhanced version PLD known as an extended range phaselocked detector (ERPLD) is capable of further threshold reduction. The most popular PLD is a second order type I system employing a loop filter having one real pole and one real zero.

One implementation of an ERPLD calls for the addition of a differentiator to the standard loop filter which replaces …

Protective Laboratory Measures For The Flexible Wall Permeameter And The Atterberg Limits Tests Using Hazardous And Toxic Chemicals, Robert A. Tetla

Theses

Safety procedures for performing geotechnical testing with hazardous and toxic materials, excluding radioactive wastes, are developed for the Flexible Wall Permeameter and the Atterberg Limits Tests. The tests were evaluated in detail to determine the critical points at which the technician would be exposed to the hazardous and/or toxic permeant. It was found that the following safety measures should always be taken; 1) the apparatus and all testing should be undertaken in a sliding sash hood using the proper face velocity, 2) air monitoring using a personal dosimeter and/or a detector tube is required to assure that the concentration of …

Improving The Capabilities Of The Chemical Engineering Simulation System (Chess) Computer Program, Thomas Zvolensky

Theses

Chemical process simulation programs have become an indispensable tool to chemical engineers in the preparation of heat and material balances, and energy conservation studies. Since the 1960's several dozen process simulators have been developed which are in use today within companies and through computer service bureaus. Due to advances in the areas of unit operation analysis and thermodynamic relations, these programs require periodic modification. This thesis describes the programming modifications made to the Chemical Engineering Simulation System (CHESS) version 2.0, computer program. This undertaking was considered warranted since no improvements have been made to CHESS since its release in 1971. …

Putting The Lid On Spares : A New Estimating Concept, George Zahodnick

Theses

Government standards and regulations, such as the CASB and FAR can be used as a guide by Contractors in preparation for negotiating orders for spare parts. More recently, in response to bad publicity involving spares, Contractors and Government officials have shown a trend toward greater micromanagement in the military acquisition process.

Spares proposal preparation, which was already often time consuming relative to dollars proposed for parts, has become an extremely serious subject often requiring additional levels of internal review and comprehensive supporting documentation. As a result, a considerable amount of new business expenditures can be associated with preparing proposals for …

Managing The Transition Of An Army Program From Engineering Development Into Production, Thomas Joseph Thomas

Theses

An overview of the entire Army Research, Development, and Acquisition process is presented. The research, development, test and evaluation phases are detailed. Special emphasis is placed on the Army Producibility Engineering and Planning Program. Examples of the different elements of our Army Production program are described. Finally, the focal point during the transition, the Milestone III and the events surrounding it, are discussed.

Application Of Manufacturing Resources Planning To Repetitive Manufacturing Environments, Irma L. Yuen

Theses

Most of the methodology for Manufacturing Systems has been devoted to Job Shops. Frequently the assumption has been made that, because Job Shops are the most complicated their methodology should fit Repetitive Manufacturing as well.

For years the Repetitive producers had been ignored as Production and Inventory Control Techniques were developed, implemented and refined to assist discrete Job Shops environments with Material Planning problems.

The application of modern Production and Inventory Control Techniques especially MRP II in the Repetitive Manufacturing Industries is receiving increasing attention from experts in the Production and Inventory Control field.

During the research for this Thesis …

Buckling Of Some Grooved Columns, Clovis Georges Baaklini

Theses

Columns with two types of transverse grooves are analyzed: a one-sided groove whose bottom is parallel to a vertical plane and cross-section is constant, and a concentric uniform groove. Then, for illustration and to be more specific, round columns are selected such that the cross-section becomes partially circular, for one-sided grooves and totally circular for a concentric groove. The columns are simply supported at both ends and subjected to a compressive eccentric load P at eccentricity e. The static equilibrium of such columns is studied via two types of solutions: the solution to three-segment column and a substantially simpler but …

An Integrated, Interactive Analysis And Design Of High-Rise Buildings On Micro-Computers, Vijayakumar Balusu

Theses

The implementation of Computer-Aided-Software, coupled with matrix and finite element techniques permitted the analysis and design of structures to the desired degree of accuracy and modelling. The successfulness of micro-computers in a vastly business oriented market has prompted the structural engineer to take advantage of cheaper and efficient micro-computers in the analysis and design of structures particularly the high-rise buildings. The availability of a comprehensive, integrated software for the analysis and design of high-rise building frames that can be operated on a micro-computer is either not currently available in the market or the available software programs do not fulfill the …