Engineering Commons^™

Cylindrical Laser Resonators, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A general class of cylindrical laser resonators is described in which the radiation propagates partially in the radial direction. There is a strong focusing of energy at the axis of such resonators. The low-loss cavity modes are related to ordinary gaussian beam modes. Two limiting forms are the disk laser and the tube laser, and some applications are considered.

Teacher Education In Elementary School Industrial Arts, James Earl O'Bannon

Dissertations and Theses @ UNI

The purpose of this study was to (1) determine how many institutions of higher learning (ones listed in the 1972-73 Industrial Teacher Education Directory) offer courses in elementary school industrial arts, (2) to examine the status and content of industrial arts for the elementary school courses offered by these institutions of higher learning for elementary teachers, (3) to determine if they have changed since the last comprehensive study, (4) to compare the content of elementary school industrial arts courses with these standards set up by a National Conference on Elementary School Industrial Arts and other specialists in the area.

Flowware -- A Flow Charting Method To Describe Digital Systems, Wayne Everett Omohundro

Doctoral Dissertations

"FLOWWARE is an interactive, graphical language to aid in the understanding and design of digital networks. The language is based upon the concept of flow charting. The user specifies the register layout of the system and the sequential operation in the form of a diagram on a graphics terminal. FLOWWARE makes full use of a local minicomputer to perform editing and drawing functions, and a remote large computer to perform translation and simulation. This division of labor allows the user to build his description off-line without having the remote computer program active"--Abstract, page ii.

Convergence Of Material Balance In Mathematical Simulation Of Petroleum Reservoirs, Abdul Rashid Merchant

Doctoral Dissertations

One criterion for determining the precision of pressures calculated by a simulation model is the accuracy of the material balance. A high degree of precision in the calculated pressures is a necessary condition for elimination of error in prediction of fluid migration in the reservoir. However, this condition is not sufficient to guarantee accuracy of the simulation, since inaccuracies are introduced by truncation errors, machine round-off errors, and by the use of finite difference approximations to represent nonlinear partial differential equations.

A new procedure called Error Matrix Technique has been developed for reduction of material balance errors. This reduction is …

Numerical Simulation Of Individual Wells In A Field Simulation Model, Ali Mohammed Akbar

Doctoral Dissertations

"Conventional numerical simulation of hydrocarbon reservoirs is inadequate for the prediction of bottom-hole pressures at production wells. This problem can be overcome by using a special mathematical model which combines individual well simulation with reservoir simulation. Severe computational instability is commonly encountered in the radial models due to the relatively small grid-blocks and high fluid velocities in the vicinity of the well bore. This instability is found to be more pronounced during depletion of the reservoir when the pressure near the well bore is below bubble-point pressure. A new technique is introduced here for saturation calculations in the critical region …

Transient State Analysis Of Separated Flow Around A Sphere, Ching-Liang Lin

Doctoral Dissertations

"Transient state solution of the Navier Stokes equation was obtained for incompressible flow around a sphere accelerating from zero initial velocity to its terminal free falling velocity. By assuming rotational symmetry around the axis in the falling direction, the Navier Stokes equation and the continuity equation were simplified in terms of vorticity and stream function. The instantaneous acceleration of the falling sphere was calculated by considering the difference between the gravitational force and the drag force in a transient state. The governing partial differential equations were non-dimensionalized. A set of implicit finite difference equations was developed. In order to obtain …

Stability Of The Developing Laminar Flow In A Circular Tube, Lung-Mau Huang

Doctoral Dissertations

"An investigation is made of the linear stability of the developing laminar flow of an incompressible fluid in the entrance region of a circular tube. Both axisymmetric and non-axisymmetric small disturbances are considered in the analysis. The stability characteristics of the fully developed flow are also re-examined. The main flow velocity distribution used in the stability analysis is that from the solution of the linearized momentum equation. The governing equations for the disturbances and the boundary conditions constitute an eigenvalue problem which is solved by a direct numerical integration scheme along with an iteration technique. The solution starts with a …

Electro-Reduction Of Bromate On Mercury, Jaw-Shin Chang

Doctoral Dissertations

"The electrochemical reduction of BrO⁻₃ was studied on a stationary Hg electrode in neutral and basic solutions containing K⁺, Na⁺, and L⁺. Coulombic efficiency studies showed Br⁻ to be the predominant reduction product. The steady state kinetic parameters include Tafel slopes of ca. -0.120 V, approximate first order activity dependences for both BrO⁻₃ and the accompanying cation, and no pH dependence. A reaction scheme is proposed which involves BrO⁻₃ "bridged" to the electrode by the accompanying cation. It is suggested that the "bridging" is a result of ion-pairing in the electrical double-layer"--Abstract, page 1.

Measurement Of Molecular Diffusivities Of Liquid Alkane Systems, James W. Moore

Doctoral Dissertations

"An unsteady-state porous frit method of diffusion coefficient measurement, recently developed in this laboratory, was improved and expanded upon. The experimental technique has been refined and documented. The unsteady-state diffusion of an initially 0.5 N NaCl solution into pure water (effective diffusivity -1.480 x 10^-5 cm²/sec) was employed as the calibration standard. An overall calibration precision of ±4% was obtained. Diffusion times of two hours or less were used for the non-aqueous diffusivity measurements. The validity of this measurement technique was confirmed by the agreement of the measured self-diffusion coefficient of n-heptane (25⁰C) with literature values.

A …

Investigation Of Roof Shales In Illinois Coal Mines, Peter J. Conroy

Doctoral Dissertations

"This thesis describes an investigation of the relationships among the composition, physical properties and the performance of roof shales in Illinois coal mines. The study included cataloging the physical and mineralogical properties of typical roof shales, determining the interrelationships of the properties and defining the factors in the rock which effect deterioration. From the results, a classification system has been developed which may provide a means for evaluating coal mine roof stability.

A coring apparatus was developed for obtaining in situ samples from mine roofs. Five coal mines with varying geologic and roof conditions were sampled. Precautions were taken to …

The Effects Of High Pressure And Temperature Environments On The Properties Of 6061-T651 Aluminum, Patrick George Davidson

Doctoral Dissertations

"During this experimental testing program the effects of the simultaneous application of high pressure and temperature environments on the mechanical properties of 6061-T651 aluminum were analyzed. From the data obtained at the yield and ultimate points a yield and ultimate model was developed based upon the parameters effective stress, effective strain, and the hydrostatic component of stress. This model was obtained solely from the data acquired from uniaxial tensile specimen tested at various pressures and temperatures. Two other loading paths--biaxial tension and torsion--were then used to verify the accuracy of the model. From the testing program, data were also obtained …

Prebainitic Phenomena In Aisi 86b80 And 0.8c-5.3ni Steels, Chung Lim

Doctoral Dissertations

"An ultrasonic investigation shows that the prebainitic kinetics of AISI 86B80 and 0.8C-5.3Ni steels follow t^2/3 and or t¹ time laws in the lower bainite temperature region. The data analysis indicates that these kinetics signal carbon segregation to dislocations. The simple time laws are interrupted at the bainite start time. It is shown that at this time the carbon depleted regions around dislocations transform martensitically. The lower bainite reaction is thus initiated by the formation of supersaturated ferrite through carbon segregation and the subsequent local martensitic transformation"--Abstract, page iii.

Hydrostatic Extrusion Of Waste Glass And Plastic, Subhash Govind Kelkar

Doctoral Dissertations

"Waste glass and waste plastic combine to form a major portion of nonbiodegradable, solid waste. These waste products aggravate the already too serious problem of environmental pollution. Hence, a means is sought of utilizing this waste in the construction industry, thus solving two problems simultaneously - that of beautifying the environment, and of procuring inexpensive building materials.

Extrusion is not an uncommon process as far as the manufacture of original products is concerned. Hydrostatic extrusion is a modification of the process wherein a billet or slug of some material is forced to flow through a die under the influence of …

Applications Of Frequency Domain Stability Criteria In The Design Of Nonlinear Feedback Systems, Allen Joseph Rushing

Doctoral Dissertations

"The Popov criterion for absolute stability of nonlinear feedback systems is applied to several example problems. Model transformations such as pole shifting and zero shifting extend the class of systems to which the criterion applies. Extensions of the criterion having simple graphical interpretations yield stronger results for systems with constant monotonic slope-bounded nonlinearities. Additional extensions lacking simple graphical interpretations in the complex plane are also demonstrated by example.

Stability throughout a region in parameter space is discussed, and the Kalman conjecture is verified for a new class of systems. The Popov criterion is also used to prove BIBO stability, process …

Methods For Predicting The Influence Of Intense Sound, Steady Flow, And Elevated Temperature On The Acoustic Performance Of Automotive Exhaust System Components, Richard Chuka Oboka

Doctoral Dissertations

"The principal objective of this investigation was to study the feasibility of developing laboratory techniques for automobile-exhaust muffler design in order to reduce the amount of on-vehicle trial-and-error testing currently required. The investigation included (1) improving the capability of existing laboratory equipment to simulate the conditions in automobile exhaust (i.e., high-amplitude pressure waves, steady flow, and elevated temperature), and (2) theoretical and experimental studies of typical acoustic elements (side-branch resonators, expansion chambers, louvered tubes) used in muffler design. The sound fields used for these studies included pure tones, single pulses (tone bursts), random noise, and simulated automobile exhaust noise.

Empirical …

Film Boiling Of Freon 113, Normal Pentane, Cyclopentane, And Benzene From Cylindrical Surfaces At Moderate Pressures, Gary Joseph Capone

Doctoral Dissertations

"An investigation of film boiling heat transfer in saturated pools of liquid Freon 113, Normal Pentane, Cyclopentane, and Benzene was made. The fluids were boiled from copper, cylindrical heat transfer surfaces, 3 inches long, and 0.55, 0.75, and 1.00 inch in diameter. The heat transfer elements were positioned horizontally in an autoclave and tested at moderate pressures of up to a pressure of 242.5 psia for Normal Pentane.

The experimental data are discussed and compared with known film boiling correlations. The known correlations were found to be inadequate in predicting heat transfer coefficients as a function of pressure, temperature difference …

Analysis Of Continuous Curvilinear Structures By Infinite Matrix Series Methods, Trinh-Ngoc Rang

Doctoral Dissertations

"The objective of this dissertation is to present two methods of structural analysis for continuous curvilinear frames by using infinite matrix series as an extension of the well-known moment-distribution method. The sum of all unbalanced moments and thrusts relaxed at joints of a continuous system can be expressed in a compact and exact mathematical expression, which is in terms of the sum of a convergent infinite matrix series. With these unbalanced forces at joints, the final support forces may be calculated in a single stage of distribution and carry-over. The convergence of the balancing process is also demonstrated. Approximate results …

Nonlinear Optimum Design Of Dynamic Damped Structures, Mark E. Botkin

Doctoral Dissertations

"A method to optimize the weight of plane frames subjected to dynamic loads is presented. Restrictions are imposed upon the maximum dynamic stresses and displacements, desirable section moduli of the constituent members, and the range of values allowed for natural frequencies. Various considerations for rigid frame design include damping, the P-Δ effect, static girder loads, static column loads and girder shears transferred to the columns. A finite difference approach is presented to evaluate the shock spectrum which is used in conjunction with modal superposition to obtain the peak upperbound dynamic displacements and stresses for multistory and multibay frames. The displacement …

Initial Surface Reactions And Nucleation Kinetics Of Boron On Atomically Clean Molybdenum Substrates, Richard Eugene Moore

Doctoral Dissertations

"A study of the chemical vapor deposition (CVD) of boron from boron triiodide (BI₃) on molybdenum has been done with field emission microscopy (FEM) and low energy electron diffraction (LEED).

A correlation of the efficiency by which BI₃ is effectively dissociated to form adsorbed boron, and the temperature of the substrate has been shown through work function measurements on the boron covered molybdenum field emitter surfaces. The boron-induced work function change of molybdenum has been shown to be in agreement with a theoretical model which predicts positive, as well as negative work functions for adsorbate-substrate systems. It …

Implementation Of Recursive Algorithms For Delay-Time Estimation Using The Fast Walsh Transform, Donald Robert Nelson

Doctoral Dissertations

"Use of the fast Walsh transform to resolve noisy signals into Walsh function series to digitally implement maximum-likelihood parameter estimators for real-time use is investigated. Realization of estimators which seek a null in the derivative of the log-likelihood function, instead of direct maximization, results in feedback algorithms which yield considerable savings in computation time and storage. Performance of these feedback delay-estimation algorithms is characterized in terms of mean-squared error (MSE) and response to a delay step by Monte Carlo simulation. The effect of changing the number of points in the transform on the MSE is also investigated. Hard limiting of …

Film Boiling Of Benzene, Freon 113, Freon 11, And Normal Pentane From Horizontal Surfaces At Atmospheric Pressure, Richard Stanley Kistler

Doctoral Dissertations

"A film boiling study was conducted with five different area flat plates at atmospheric pressure for benzene, Freon 113, Freon 11, and n-pentane. The heat transfer surface was horizontal for all tests.

The data were compared to the correlations commonly used for heat transfer. The common correlations were found to be in error for small surface sizes, but adequate for all fluids except benzene for the largest surface, a semi-empirical equation which correlates the available data as a function of surface diameter was derived and discussed"--Abstract, page iii.

An Application Of Residual Relaxation To Mathematical Simulation Of Petroleum Reservoirs, Grufron Achmad

Doctoral Dissertations

"Stability and convergence have long been primary concerns in the application of numerical techniques to the simulation of petroleum reservoir performance. An iterative method based on sequentially reducing the residual to zero at each grid point has been developed. It has been shown analytically that this residual relaxation method is stable, convergent, and consistent.

A three-phase areal model was developed to simulate a hypothetical homogeneous petroleum reservoir, and various computational methods were tested with this model. The residual relaxation method developed in this study (RELAX) was found to converge as rapidly as SIP, and much faster than either LSOR or …

Linear Stability Of Non-Parallel Flow In The Entrance Region Of Ducts, Francis Chung-Ti Shen

Doctoral Dissertations

"An investigation is made of the linear stability of the developing flow of an incompressible fluid in the entrance region of annular ducts, circular tubes, and parallel-plate channels. Small axisymmetric disturbances for annular duct and tube flows and small two-dimensional disturbances for channel flow are considered in the analysis. In formulating the stability problems, account is taken of the transverse velocity component of the mainflow. This results in the modified Orr-Sommerfeld equations, one for annular duct and tube flows and the other for channel flow. The mainflow velocity fields utilized in the stability analysis are those from the solutions of …

Rock Fragmentation By Subsurface Thermal Inclusions - A Finite Element Study, Mahendrakumar Ramkrishna Patel

Doctoral Dissertations

"Although rock tunneling machines are being used extensively with performance and cost advantages over traditional drill and blast methods, their usefulness for hard rock excavation is far from being practical due mainly to the inability of present day mechanical cutters to penetrate these rocks economically. Among various novel techniques that are being investigated, internal heating methods seem to be the most promising. This investigation is concerned with a feasibility study of thermal rock fragmentation using heat to create in-depth thermal inclusions.

The three-dimensional problem of in situ rock fragmentation involves parallel rows of equidistant holes drilled to a constant depth. …

A Study Of The Dynamic Loading Of Hydrodynamically Lubricated Journal Bearings, Nader Khorzad

Doctoral Dissertations

"The analytical and experimental investigation presented here examined the response of a full journal bearing to a unidirectional dynamic load. Frequency response of the bearing at different eccentricity ratios was investigated. It was concluded that the response of the bearing varies with eccentricity. The experimental data obtained was compared to an analytical model which considered inertial, damping, and elastic characteristics of the lubricant film. An investigation of film pressure revealed that the pressure due to journal center acceleration is smaller than the hydrodynamic and squeeze-film pressures"--Abstract, page 1.

Numerical Simulation Of Heat, Mass, And Momentum Transfer In An Atmospheric Boundary Layer, Darrell W. Pepper

Doctoral Dissertations

"Considerable interest has developed in recent years to understand transport phenomena in thermally stratified boundary layers. More complete knowledge in this field is needed to improve the prediction of the diffusion of air pollutants in the lower atmosphere as well as in forecasting air-water circulation for weather conditions.

The atmospheric boundary layer is modeled using the equations of continuity, momentum, energy, and concentration. Closure of this set of partial differential equations is hindered by the turbulence terms. Using turbulence kinetic energy, the system of equations is closed by internally determining the exchange coefficients of heat, mass, and momentum along with …

Premartensitic Elasticity Of Fe-Ni Invars, Bryce Linn Shriver

Doctoral Dissertations

"The premartensitic temperature dependence of ultrasonic wave propagation in Fe-30 pct Ni polycrystals and Fe-32 pct Ni single crystals was measured by using a continuous wave technique. As the temperature was lowered to within 10°C of the M_s, a nonlinear decrease of the relative shear velocity was observed. This effect is related to dislocation stacking fault instabilities which may trigger the martensitic phase transformation. In addition, the single crystals show a frequency dependence of the shear elastic constant C' well above the M_s. The dispersion is believed to be caused by fluctuations in the anisotropic molecular …

Dynamic Instability And Ultimate Capacity Of Inelastic Systems Parametrically Excited By Earthquakes, Wu-Hsiung Tseng

Doctoral Dissertations

"A procedure of analysis is presented for determining the dynamic instability and response of framed structures subjected to pulsating axial loads, time-dependent lateral forces, or foundation movements. Included in the analytical work are the instability criterion of a structural system, the finite element technique of structural matrix formulation, and the computer solution methods.

The dynamic instability is defined by a region in relation to transverse natural frequency, longitudinal forcing frequency and the magnitude of axial dynamic force. The axial pulsating load is expressed in terms of static buckling load for ensuring that the applied load is not greater than the …

Nucleate Boiling From Polymer Coated Surfaces., David Franklin Warner

Doctoral Dissertations

"This study consisted of an examination of both the effects of nucleate boiling on polymer coated surfaces and the effects of the polymer coated surfaces on the nucleate boiling curve. The nucleate boiling curve (the curve resulting from plotting heat transferred per unit area versus the temperature difference between the boiling surface and the liquid pool) of the polymer coated surfaces were compared with the nucleate boiling curve of gold-plated surfaces with no polymer coat and it was found that the thicker the polymer coat, the more the curve deviated from that of the metal uncoated surfaces.

All surfaces were …

Evaluation Of Safety Improvements At Highway - Railway Grade Crossings : Interim Report, Thomas Allan Butcher

JTRP Technical Reports

No abstract provided.