Engineering Commons^™

Natural Convection In Shallow Inclined Enclosures, Effendy Arif

Mechanical & Aerospace Engineering Theses & Dissertations

A two dimensional natural convective flow in a shallow inclined enclosure has been considered. A mathematical model has been developed to simulate the flow. The system of governing equations has been solved using finite-differencing techniques and the alternating direction implicit method.

The effect of the Raleigh number, the enclosure aspect ratio and orientation on the heat transfer and flow development have been studied by determining the Nusselt numbers and analyzing a number of contour maps of temperature and stream function fields, and velocity profiles. The Nusselt number has been found to increase with the Raleigh number, the enclosure aspect ratio, …

Mechanical Properties And Microstructure Examinations Of Aluminium-Steel Composites, Mervet Ibrahim Shenouda

Archived Theses and Dissertations

No abstract provided.

Solidification Of Aluminium Alloy Ingots, Hassan Abdel Kader Abdel Salam

Archived Theses and Dissertations

No abstract provided.

Correlation Of Thixotropic Parameters And Related Tests Of Blood From Human Subjects, Walter Fabisiak

Dissertations

The flow behavior of human blood is an important facet of the circulatory system as it affects all of the organs of the body. The rheological properties of whole blood provide a means of analyzing the flow of red cells and plasma through the microcirculation. A recently observed rheological characteristic of whole human blood is thixotropy, a time-dependent phenomenon. This phenomenon is caused mainly by the redistribution of an aggregated form of erythrocytes, known as rouleaux, and the non-aggregated, single erythrocytes. In order to further define and analyze the thixotropic properties of blood, the Huang model is used to quantitatively …

Thixotropic Properties Of Whole Human Blood, Jen An Su

Dissertations

The rheological property of whole blood from various human subjects was studied with a Weissenberg Rheogonio-meter, modified with a continuously variable speed drive. Experimental data showed a hysteresis loop in the shear stress versus the shear rate plot and a torque-decay in the shear stress versus the shearing time plot which is under a constant shear rate. The rheological equation previously developed by Huang was employed to define the thixotropic parameters of each whole blood sample based upon the recorded rheograms.

The altered thixotropic parameters for the blood from patients with open heart surgery at different clinical stages were quantitatively …

The Minimum Maximal-Cube Covering Approach To Switching Theory, Yu-Tsang Gene Hwang

Dissertations

This dissertation is devoted to the construction of a new algebraic structure for the K-map so that algorithms and theorems can be derived for the minimization of Boolean functions and at the same time provide for the manipulation of Boolean functions as freely as one could on the K-map.

Computer programs have been included to demonstrate the theory and numerous examples of various complexity have been worked out in the appendices.

Impingement Of An Axi-Symmetric Jet On A Flat Surface, Amir J. Daibes

Theses

An incompressible, inviscid irrotational flow model was used to represent the normal impingement of a circular axisymmetric jet upon a flat plate. An analytical investigation was conducted to determine the free surface of the jet and the solution of the potential flow problem was obtained using finite difference techniques for jet height-to-nozzle radius ratio of 2.4.

The velocity and pressure distributions at the plate surface and along the jet centerline were obtained.

The results from the finite difference solution are in close agreement with other most recent results from available experimental, and approximate solutions to the potential flow problem.

Temperature Dependency Of The Group Interaction Parameters In The Agsm And Unifac Models For The Prediction Of Heats Of Mixing, Ignatius Okoronkwo Ojini

Theses

A four-parameter group-contribution model (UNIFAC) has been developed for the prediction of heats of mixing of non-electrolyte mixtures. Both the UNIFAC and AGSM models are evaluated over a wide range of temperature dependencies of the group interaction parameters. The UNIFAC model has been chosen over the AGSM model and an optimum parameter-temperature relationship has been established.

Adopting the optimum temperature dependency, group inter-action parameters have been calculated using UNIFAC for the prediction of four types of mixtures: n-Alcohols/n-Alkanes; Benzene/n-Alkanes; Nitriles/n-Alkanes; Amines/n-Alkanes.

An Experimental Study Of Photopolymerization In A Continuous Stirred Tank Reactor, Songvit Setthachayanon

Theses

An experimental study was carried out on the control of CSTR by on-off regulation of light intensity for the photo-sensitized polymerization of styrene. The controllability of the reaction temperature, the advantages of operating at metastable states, and the molecular weights of the polymer formed were discussed. The influence of feed temperatures, sensitizer concentrations, and residence times on the reactor performance characteristics were also discussed. Experimental results showed that polymer formed at the metastable state had a higher average chain length and narrower molecular weight distribution than that formed at the low stable state. While increasing the residence time shifted the …

A Microprocessor Based Digital Logic Simulator, Kevin Dresher

Theses

It is the intent of this thesis to acquaint the reader with a tool which is available for use in the digital circuit design field. The reader is now able to totally simulate via DLS the digital logic design he creates on paper before it ever takes a hardware form. The computer program accepts a detailed description of the schematic and creates timing diagrams, loading statistics, cross references, and various lists for future documentation.

The user needs no programming knowledge and will find the requirements to run a simulation with DLS extremely user oriented. The simulation descriptions and command language …

The Characterization Of The Oxygen Transfer Capabilities Of Fermentors, Joseph Stephen Adamca

Theses

A method of characterizing the oxygen mass transfer capabilities of fermentors was developed where volumetric oxygen mass transfer coefficients are obtained using a modified sulfite oxidation method in conjunction with on line digital data processing. Carboxymethylcellulose is used in the reaction media to simulate the viscosity of typical non-Newtonian fermentation broths. Using this method, instantaneous values of volumetric oxygen mass transfer coefficients can be obtained for various combinations of agitation and airflow rates in different fermentor configurations. This data is useful in the scale up or scale down of fermentors.

Data obtained using this method have revealed that for a …

Analysis Of Unsteady-State Heat Conduction In A Cylinder With The Finite Element Method, Richard F. Bernard

Theses

Unsteady-state heat conduction in a cylinder of finite dimensions with constant physical and thermal properties was analyzed with the finite element method. Symmetry of the cylinder and application of Newman's method reduced the problem to two independent one-dimensional problems. Finite element equations for the axial and radial dimensions were developed utilizing Galerkin's method of weighted residuals. Crank-Nicholson approximations were used for time derivatives. A computer program was written for solution of the finite element equations.

Solutions obtained were conditionally stable; dependent on the value of the ratio KΔt/ρCpl². For values of the ratio less than 1/3, errors in …

The Removal And Recovery Of Fluoborate From Plating Rinse Waters, Terrence A. Hunter

Theses

Fluoborate poses a problem to electroplaters when discharged in their wastestreams. Therefore, a method for removing fluoborate from rinse waters is necessary. An ion floatation technique using a surfactant was developed at N.J.I.T. to perform this job. However, this technique requires long time periods therefore other methods were investigated.

Ultrafiltration was investigated as a replacement for the ion floatation technique. It would cut down the time required for the fluoborate removal. Also, electrolysis and the addition of excess acetic acid were tried in an attempt to separate the fluoborate and the surfactant in the ultrafiltration retentate. This system was evaluated …

The Use Of Thermal Analysis In The Identification And Characterization Of Fibers Of Forensic Interest, Ronald J. Coffey

All-Inclusive List of Electronic Theses and Dissertations

This study investigates the use of thermal analysis for the identification and characterization of fibers for forensic purposes. Fibers such as polyesters, polyacrylics, polypropylenes and nylon were investigated by Differential Thermal Analysis (D.T.A.) and Thermogravimetric Analysis (T.G.A.) to see if their resulting thermograms were characteristic of each fiber. Also, infrared analysis was performed on each fiber. In addition, such factors as heating rate and sample size along with fiber blends were studied as to their effect on thermograms. As a result of this study several important conclusions may be drawn. Although it was found that for the most part D.T.A. …

Vector Optimization Decision Convergence Algorithm (Vodca), Thomas Ward Morgan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many professions occasionally involve the selection of an alternative from among many problem solutions which have impacts in multiple-interest areas; however, due to the very nature of his work, the practicing engineer, regardless of specialty, is unavoidably engaged in this selection process. The emergence of national concern for environmental and social consequences of technical enterprises, as reflected through legislative action, has accentuated the need for multicriteria design methodologies in some areas of engineering (i.e., automotive). Consequently, interest in the development of pragmatic and theoretically sound approaches to multi-impact design situations has been keen. Any approach to multicriteria design/decision problems involves …

Treatment Of Usu Dairy Wastewaters By Lagoon Intermittent Sand Filtration, Eric M. Claus

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study of the feasibility of lagoon-intermittent sand filter treatment of dairy wastewaters from the Utah State University dairy was performed from 1978 through 1980. The report also includes an analysis of alternative dairy wastewater treatment systems utilizing a computer model.

A simple and inexpensive method of dairy wastewater treatment is needed so that the small (50- 300 cows) dairy farmer can meet the 30 mg/ ~ of BODs federal effluent standard and still earn a profit. The influent to the USU dairy treatment system, the lagoon effluent and the filter effluent were sampled during the summers of 1978 and …

A Cavity Absorber For A Focusing Solar Collector, Andrew W. Crapo

Retrospective Theses and Dissertations

The concept of a cavity absorber for use with a focusing parabolic trough is developed in this paper. A mathematical model is formulated and used to compare different absorber geometries. Limitations of the model are discussed and within the range of materials and fabrication methods available, the choice of a cylindrical cavity is substantiated. Relative sizes of the gap and cylinder are chosen for a given mirror arc length, focal length, and alignment error. The model is used to optimize these parameters and predict absorber and collector efficiency. The processes of building and testing the absorber are detailed, and test …

Analysis Of Traffic Accidents At Daytona Beach In Volusia County, State Of Florida, Mohammad Reza Hajian

Retrospective Theses and Dissertations

Anyone who has been tempted to cross a beach or walk along a beach is aware of the potential conflicts that can arise between pedestrians and vehicles. The competing use of the beach space results in conflicts between vehicles and pedestrians; many times the pedestrian's disregard for signed pedestrian safety provisions in the close vicinity and on the space allocated for car lanes results in avoidable conflicts. This report addresses the pedestrian and vehicle interaction at Daytona Beach in Volusia County of the State of Florida. This report has consolidated accident data for the period January 1, 1977 through July …

Statistical Fading Of A Spherical Optical Wave In Atmospheric Turbulence, Lorraine M. Locke

Retrospective Theses and Dissertations

A formula for the average fade time of the intensity of a spherical optical wave travelling through atmospheric turbulence is developed. The model employed involves isotropic, homogeneous statistics using a lognormal distribution for the channel. The analysis is based on the fact that the logarithm of the irradiance is normally distributed and uses the work of S. O. Rice who developed such an expression for a zero mean, Gaussian process. The analysis employs the covariance function and the Taylor frozen turbulence hypothesis which results in an expression for the autocorrelation function.

Electromagnetic Wave Scattering From A Rough Surface, Elie G. Nacouzi

Retrospective Theses and Dissertations

This was a study to measure surface roughness using scattering of electromagnetic waves in the Ka and X microwave frequency bands. The detected fluctuations of the reflected field intensity is a measure of surface roughness. The reflected field intensity depends on the wavelength, the angle of incidence and the electrical properties of the media. Since the surface presents irregularities with randomly distributed facets, the characteristics of the rough-surface reflected wave can only be described by the statistical properties of the field intensity. The dependence of the normalized moments of the returned scatter on distance from the rough surface to the …

Noise Description And Noise Control At The Federal, State, And Local Level, Bobby L. Henning

Retrospective Theses and Dissertations

Noise, that undesirable portion of the ever-present sounds of our environment, has until the last decade, been considered as an unavoidable by-product of our rapid population growth and its accompanying mechanization. As awareness of adverse health effects from noise exposure grew, the Federal government, as protector of the public health and welfare, took the initial steps to control noise pollution. Federal legislation, beginning with the Clean Air Amendments of 1970, has been promulgated to control major offenders and to assist State and local governments in their endeavors to provide the public with an environment free from harmful noise levels. This …

Speed Control Of Dc Shunt Motor For Electric Car Use, Mahmood Shahi

Retrospective Theses and Dissertations

This report describes the speed characteristic and various methods of speed control of DC shunt (separately excited) motors, especially for application in electrical vehicles. The basic behavior of the DC motor is discussed, along with traditional and modern techniques of speed control. As an example, a speed controller for a shunt motor (built and tested by the author) is discussed. Two types of speed controllers for electric cars are discussed, and the performance results for an experimental electric car are presented. Finally, a design for a 24 HP car motor controller using both armature and field control was simulated on …

The Effects Of Introducing Skewness Into Capital Rationing Decision Models, Edet Jonathan Ekere

Retrospective Theses and Dissertations

When investment projects are described by subjective probability distributions, the measure of investment worth becomes a difficult task. One of the basic assumptions underlying investment analysis under risk is that decision makers would base their decisions on only the first two statistical moments of the probability distribution of returns. However, the mean and variance can adequately describe only certain symmetric distributions such as the normal and the uniform distributions. As a result, if probability distributions of investment returns are actually asymmetric, the classic first two moments analysis ignores information (skewness) that is needed to make a better investment decision. Even …

Optimum Monotonic Step Response Filters, Peter H. Halpern

Retrospective Theses and Dissertations

The problem of designing sharp cutoff filters with monotonic step responses is addressed. The impulse responses of the filters are expanded in terms of finite duration trigonometric polynomials. The coefficients of the trigonometric polynomials are obtained, for arbitrary frequency penalty functions, by solving a generalized eigenvalue problem. Once the trigonometric polynomial is specified the network can be synthesized with known techniques. Two theorems which assist in the numerical solution are proven.

Analytic And Experimental Studies Of A True Airspeed Sensor, Joseph Yao-Cheng Shen

Mechanical & Aerospace Engineering Theses & Dissertations

The objective of this study was to analyze and design a true airspeed sensor which will replace the conventional pitot-static pressure transducer. This sensor should have the following characteristics: the flow phenomenon is vortex procession, or the "vortex whistle", it should have no moving parts, and also is to be independent of temperature, density, altitude or humidity changes. This sensor has been designed mainly for small commercial aircraft with the airspeed up to 321.9 km/hr (200 mph).

In an attempt to model the complicated fluid mechanics of the vortex precession, three-dimensional, inviscid, unsteady, incompressible fluid flow was studied by using …

Influence Of Nonequilibrium Radiation And Shape Change On The Flowfield Of A Jupiter Probe With Ablation And Mass Injection, Sundaresa Venkata Subramanian

Mechanical & Aerospace Engineering Theses & Dissertations

The influence of nonequilibrium radiative energy transfer and the effect of probe configuration changes on the flow phenomena around a Jovian entry body is investigated. The radiating shock-layer flow is assumed to be axisymmetric, viscous, laminar and in chemical equilibrium. The radiative transfer equations are derived under nonequilibrium conditions which include multi-level energy transitions. The equilibrium radiative transfer is calculated with an existing nongray radiation model which accounts for molecular band, atomic line and continuum transitions. The nonequilibrium results are obtained with and without ablation injection in the shock layer. The nonequilibrium results are found to be influenced greatly by …

The Development Of A Stepped Frequency Microwave Radiometer And Its Application To Remote Sensing Of The Earth, Richard Forrest Harrington

Electrical & Computer Engineering Theses & Dissertations

The design, development, application, and capabilities of a variable frequency microwave radiometer are described. This radiometer has demonstrated the versatility, accuracy, and stability required to provide contributions to the geophysical understanding of ocean and ice processes. The design technique utilized a closed-loop feedback method, whereby noise pulses were added to the received electromagnetic radiation to achieve a null balance in a Dicke switched radiometer. Stability was achieved through the use of a constant temperature enclosure around the low loss microwave front end. The Dicke reference temperature was maintained to an absolute accuracy of 0.1 K using a closed-loop proportional temperature …

The Significance Of Peel Stresses In Cyclic Debonding, Richard A. Everett Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

One of the possible failure modes in adhesively bonded joints is cyclic debonding -- progressive separation of the adherends by cyclic failure of the adhesive bond. In this study cyclic debonding in an adhesively bonded crack-lap shear specimen has been investigated by means of a linear elastic finite-element analysis and a series of constant­ amplitude axial fatigue tests. The primary purpose of this study was to test the hypothesis that cyclic debonding is due largely to tensile peel stresses in the adhesive.

The results of this study have indicated that not all of the tensile peel stresses in the adhesive …

A Dimensionality Reduction Algorithm For The Karhunen Loeve Transform, Salomi T. Charalambous

Computational Modeling & Simulation Engineering Theses & Dissertations

The Karhunen Loeve Transform has conclusively been shown to be the optimum data compression algorithm for signals belonging to the same second order stationary process. Consequently, researchers have been searching for a fast implementation for the transform. Fast imple­mentation methods similar to those developed for other orthogonal transforms are generally not applicable to the Karhunen Loeve Transform (KLT). Also, since the basis vectors composing the transformation matrix of the KLT are the eigenvectors of the covariance matrix of the input process, they must be computed first. The research re­ ported here is an attempt to reduce the dimensionality of the …

The Effect Of Residual Stress Distribution On The Ultimate Strength Of Tubular Beam-Columns, Steven L. Barrett

Dissertations and Theses

Using data for the longitudinal residual stress distribution in welded steel tubes, curves describing these distributions are selected for study. Each of these curves are checked for static balance across the tube cross section. The curves that exhibit an imbalance are adjusted by a combination of a simplified model for each and the use of a computer program that is developed to calculate the resulting forces and moments on the cross section. The residual stress in the area of the tube wall opposite the longitudinal weld is found to be the most important in the adjustment to obtain exact equilibrium. …