Engineering Commons^™

Concluding Session, Multiple Authors

International Conference on Case Histories in Geotechnical Engineering

No abstract provided.

Laser-Induced Surface Diffusion, Cheng-Hsiao Wu, Jonathan I. Gittleman

Electrical and Computer Engineering Faculty Research & Creative Works

A Brownian motion model for laser-induced surface diffusion is proposed to account for the kinetics of surface transport of the evaporated molecules from a thin discontinuous film under a focused laser beam. The model is solved exactly where the evaporation rate of the molecules is assumed to be proportional to the temperature rise above the ambient of the absorber layer. The surface diffusion constant and molecular velocity are obtained by comparing the results of calculations with transmission electron micrographs of recorded pits in Te trilayer opticial discs. These values are in good agreement with Einstein's relation.

Designing Fire Protecton For Steel Beams, American Iron And Steel Institute, Subcommittee On Fire Technology Of The Committee On Construction Codes And Standards

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Steel Deck Institute, Inc. Design Manual For Composite Decks, Form Decks, And Roof Decks, Steel Deck Institute

Steel Deck Institute (SDI) Specifications and Manuals (1939 - present)

No abstract provided.

Proton Damage In Gaas Solar Cells, John W. Wilson, G. H. Walker, R. A. Outlaw

Mining Engineering Faculty Research & Creative Works

A simplified model for the short-circuit current reduction caused by proton-induced radiation damage is described. The model accounts for the nonuniformity of defect production within heteroface GaAs shallow junction solar cells. The results from the model show agreement with the strong energy dependence observed in proton radiation damage experiments.

Equivalent Electron Fluence For Space Qualification Of Shallow Junction Heteroface Gaas Solar Cells, John W. Wilson, L. V. Stock

Mining Engineering Faculty Research & Creative Works

It is desirable to perform qualification tests prior to deployment of solar cells in space power applications. Such test procedures are complicated by the complex mixture of differing radiation components in space which are difficult to simulate in ground test facilities. Although it has been shown that an equivalent electron fluence ratio cannot be uniquely defined for monoenergetic proton exposure of GaAs shallow junction cells, an equivalent electron fluence test can be defined for common spectral components of protons found in space. Equivalent electron fluence levels for the geosynchronous environment are presented.

Smemax? Caution!, Jerome A. Westphal

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The SMEMAX Transformation was tested on samples generated from log-Pearson Type III and Gumbel Extreme Value Type 1 distributions. Although the transformation results in a distribution with a skew near zero, it is not a true normal distribution. The coefficients of kurtosis for the transformed distributions are always less than three and when the parent distribution approaches a reverse-J shape, the transformed distribution is bimodal. When the skew coefficient of the logarithms of events is -0.5 or greater for samples from the log-Pearson Type III distribution, the SMEMAX procedure underestimates the magnitude of events with return periods of 50 yr …

On The Relation Between Triangular Matrix Decomposition And Linear Interpolation, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

The December 1983 Letter by C. W. Therrien Concerning the Relation between Triangular Matrix Decomposition and Linear Prediction is Extended to Include Linear Interpolation. © 1984 IEEE

A Microprocessor-Controlled Message Display System, Paul D. Stigall, Brian E. Lenharth

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Approximate Tolerance Limits And Confidence Limits On Reliability For The Gamma Distribution, Lee J. Bain, Max Engelhardt, Wei Kei Shiue

Mathematics and Statistics Faculty Research & Creative Works

No abstract provided.

Structural Analysis And Solution Of Systems Of Algebraic Design Equations, N. (Neil) L. Book, W. F. Ramirez

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new method for expressing the structure of a system of equations is developed using a type of occurrence matrix entitled the functionality matrix. The functionality matrix indicates not only the occurrence of variables in equations but also the functional form in which they occur. Since the difficulty of solving an equation for a variable is related to its functional form, analysis of the functionality matrix provides explicit information on the difficulty of solution of the solution of the equation. A methodology for the solution of design problems by digital computers is described. This methodology operates on the functionality matrix …

A Stochastic Model For A Small-Time-Interval-Intermittent Hydrologic Process, Charles Darwin Morris

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A methodology is developed for the generation of intermittent small-time-interval (15-min.) precipitation. This methodology consists of three components: a probabilistic wet-and-dry sequence component; a Markovian precipitation distribution component; and a regressive spatial-distribution component. The theory of stochastic hydrologic modeling is described and procedures by which this theory can be applied to a hydrologic time series are presented. In particular, the application of the procedures to small-time-interval-intermittent hydrologic processes is given. The methodology is demonstrated by application to an actual precipitation network, the Boneyard Creek raingage network in Champaign-Urbana, Illinois, U.S.A. The trend in frequency of precipitation amounts from the 89-yr. …

Generalized Root-Loci Theory For The Static Scherbius Drive, B. Lequesne, Aaron J. Miles

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Generalized root-loci techniques, developed in the mid 70's for squirrel cage motors, have been extended in the static Scherbius configuration to wound rotor, slip energy, recovery systems. This arrangement is now applied to large power drives in the 0.5 to 50 MW range. In this paper, general results applicable to all machines are presented for the open-loop control scheme, but only the sub synchronous mode of operation in which a voltage source type inverter is used is addressed. Copyright © 1984 by The Institute of Electrical and Electronics Engineers, Inc.

Defect Structure Of Mg‐Doped Lacro3 Model And Thermogravimetric Measurements, B. K. Flandermeyer, M. M. Nasrallah, A. K. Agarwal, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Chemical stability and cation stoichiometry determine the applicability of LaCrO₃ as a high‐temperature oxide electrode. A model for the behavior of acceptor‐doped LaCrO₃, as a function of oxygen activity is proposed. The model is in agreement with experimental data on Mg‐doped LaCrO₃. Stability regimes and compensation mechanisms at various oxygen activities and temperature are presented. Copyright © 1984, Wiley Blackwell. All rights reserved

Experimental Investigation Of The Field And Stray Losses Of The End Bells Of An Induction Motor, Hu Ming-Zheng, George Mcpherson

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Distribution System Protection With Decentralized Generation Introduced Into The System, Behruz Fardanesh, Earl F. Richards

Electrical and Computer Engineering Faculty Research & Creative Works

Cogeneration from renewable energy sources has been universally proposed as a partial alternative to the solution of our nation's energy problems. New technical, safety, and operational problems are introduced when this generation is placed into a distribution grid. Addressed is the problem of distribution system protection with the introduction of cogeneration sources and the changes and modifications which may be required in the application of present-day protection devices. A sample system is considered, and system protection and coordination with and without cogeneration has been calculated through a digital fault and system protection coordination program. The results indicate through the study …

Electrogalvanizing And Drawing Of Steel Wires, Thomas Joseph O'Keefe Jr.

Masters Theses

"The effects of varying current density, temperature, Zn⁺² and licorice concentrations on the morphology of the zinc deposited on steel wire have been studied and compared. The plated wires were then drawn and evaluated in terms of required drawing energy and zinc loss during processing of up to 40% reduction in area. Scanning electron microscope and X-ray diffraction were used to evaluate the electrodeposits"--Abstract, page ii.

The Role Of Boron In So32 And So43 Steels, Sunil S. Moghe

Masters Theses

"In this project study was conducted with the goal of understanding the role of boron involved in structure-toughness property relationship for SO32 and SO43 steels. For a standard heat-treatment of austenitizing (1 hr.) at 1700°F, water quenching and 1 hr. tempering at 1150°F SO32 steel (with 37 ppm B) lacked in toughness, while SO43 steel (with 2 ppm B) showed good toughness. In both steels all the boron was present in the form of "soluble boron" i.e., Fe₂₃ (B,C)₆ borocarbide. Experiments were carried out to study the effect of various heat treatment parameters on the precipitation behavior of …

Thermally Stimulated Current Studies Of Barium Titanate Capacitors, Patrick Donald Martin

Masters Theses

"Thermally stimulated polarization current (TSPC) and thermally stimulated depolarization current (TSDC) measurements were used to study sample current behavior based on the thermally activated release of trapped charges and polarization mechanisms. Samples studied included laboratory-prepared barium titanate samples (the barium to titanium ratio ranging from 0.96 to 1.04) and commercial ceramic capacitors. Both TSPC and TSDC showed the current spectra of the barium titanate samples were a function of crystal structure and the Ba/Ti ratio. The TSPC/TSDC results of the ceramic capacitors showed differences between capacitor formulations. TSPC/TSDC results also showed differences between good capacitors (physically and electrically) and capacitors …

Generalized Root-Loci Theory For The Static Scherbius Drive, B. Lequesne, Aaron J. Miles

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Statistical Analysis Of Breakdown In Transformer Oil., J. Derald Morgan, M. A. Abdellah, Frank Ferracane

Electrical and Computer Engineering Faculty Research & Creative Works

The statistics of breakdown for transformer oil in a uniform field gap is an important design consideration. The theoretical probability distribution which closely fits the experimental data under 60 Hz ac voltage, positive and negative lightning impulses and positive and negative switching surges is evaluated and a statistical distribution is suggested.

Infiltration Formulas By Curve Number Procedure, Jerome A. Westphal

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

A Study On Fragmentation And Ground Vibration With Air Space In The Blasthole, Everett Ellsworth Bleakney Iii

Masters Theses

"The degree of fragmentation and the level of ground vibration from a bench blast employing standard full-column completely-coupled explosive charges are commonly controlled by varying one or more of the many dimensional variables of blast design. Blasting techniques such as decoupling and air-gapping, utilizing air space in the blasthole, have also been reported as having the potential to control rock fragmentation and ground vibration.

This investigation, using reduced-scale in situ bench blasts, examined the degree of fragmentation and the level of ground vibrations produced from the standard full-column completely-coupled, air-gapped, and decoupled methods of blasting to:

1. Compare the effectiveness …

A Thermal Contact Conductance Correlation For Mechanically Expanded Finned Tube Heat Exchangers, Mahmoud Ahmed Abu Ebid

Masters Theses

"Tests were conducted in dry vacuum environment, on eight mechanically expanded finned tube heat exchangers (with 3/8 inch outer diameter tubes) with different geometries including variation in fin thickness, fin collar length, and net interference. One of the eight heat exchangers was also tested under wet conditions. A mathematical model was used to calculate the thermal contact conductance from the experimental data. An error analysis was performed to estimate the range of error in determining the thermal contact conductance. A correlation of the dry contact conductance in terms of fin number (actual fin collar length in contact with the tubes), …

Preparation And Properties Of Phosphorus Oxynitride Glasses, Mary R. Reidmeyer

Masters Theses

"The preparation techniques and properties of phosphorus oxynitride glasses produced from sodium metaphosphate and nitride compounds are reported. A preliminary survey of possible nitride additives to sodium metaphosphate is presented along with an extended study of the two most promising nitrides, AIN and Mg₃N₂. Properties reported include: nitrogen content, dissolution rate in water, thermal expansion coefficient, softening point, glass transformation temperature, density, refractive index, microhardness, and infrared absorption"--Abstract, page 1.

The Compositional And Temperature Dependence Of Radiation-Induced Void Nucleation And Swelling In Austenitic Alloys, Bahram Esmailzadeh

Masters Theses

"The objective of this study is to introduce a model which can demonstrate the major features of the compositional and temperature dependence of radiation-induced swelling of austenitic alloys. The effective vacancy diffusion coefficient, D_V^eff, is the prime variable explored in this study. Variations in D_V^eff with composition and/or irradiation temperature are used along with the KWR nucleation theory to determine the subsequent effects of these variables on the void nucleation rate and the duration of the transient regime. The materials chosen for this study are nickel (Ni) and the Ni-Si, Fe-Ni-Cr and Fe-Ni-Cr-Si alloy systems. …

An Investigation Of Methods Of Surface Estimation With Application To The Interpolation Of Antenna Patterns, Paul Matthew Niall Feehan

Masters Theses

"The problem of estimating a surface from a set of discrete measurements lying along straight lines is considered. This situation arises when one attempts to determine the S-Band antenna gain pattern for the Space Shuttle, from measurements taken at several ground stations. The results of previous investigators concerned with the performance of surface approximation techniques for the present application, are extended in this study by examining the case where the data samples are corrupted by measurement noise. Results have been obtained using least-squares approximation with bicubic B-spline basis functions, and for an interpolation algorithm in conjunction with a spatial smoothing …

Solid Solubility Of Sulfur In Transition Metal Oxides And Stability Of Sulfates Relevant To Roasting Processes, Zeynal Karakus

Masters Theses

"Two types of sulfur equilibration experiments were carried out in this study using either a conventional thermal gravimetric analysis (TGA) technique or a horizontal tube furnace apparatus. Samples were equilibrated with flowing SO₂-O₂ gas mixtures of either 58% SO₂ or 10% SO₂.

The types of experiments were:
1. Investigation of the extent of solid solution of sulfur in ZnO, NiO, CuO, and Fe₂O₃ over a wide range of temperature.
2. Studies of compound or solid solution formation between binary sulfate mixtures of Fe-Zn, Cu-Zn, Ni-Zn, Fe-Cr, and Cd-Zn by TGA.

The …

Structural Behavior Of Cold-Formed Steel Beam Webs Subjected To Partial Edge Loading, Shin-Hua Lin

Masters Theses

"An extensive experimental investigation has been conducted to study the load-carrying capacity of cold-formed steel web elements subjected to partial edge loading which may cause web crippling or web buckling. In this experimental work emphasis was concentrated on the cold-formed steel structural members having single unreinforced webs with stiffened flanges.

In 1980, American Iron and Steel Institute (AISI) revised its "Specification for the Design of Cold-Formed Steel Structural Members.” For the design of beam webs, Section 3.5.1 of the AISI Specification provides the design criteria for web crippling. This thesis discusses the experimental work including some specimens with small length-to-depth …

Ion Implantation For Improvement Of Wear Properties Of Steels, Kenneth W. Burris

Masters Theses

"Previous research on ion implantation at U.M.R. has dealt with the development of a modified Falex Lubricant Tester as a valid wear test and its use in dose curve determination. Our recent work uses Auger surface analysis and scanning electron microscopy to gather support for a model that will tie together some of the many theories proposed as to why ion-implantation improves the surface related mechanical properties of steels"--Abstract, page ii.