Digital Commons Network^™

Current Density-Anodic Potential Curves Of Single Crystal Gaas At Low Currents In Koh, Martin E. Straumanis, J. P. Krumme, William Joseph James

Materials Science and Engineering Faculty Research & Creative Works

Single p-type, GaAs crystals of high purity, Zn doped, were used to determine whether or not the inverse octahedral {111} faces show potential differences and various rates of anodic dissolution. The Ga{111}, As{111}, {110}, and {100} faces, were polished, etched, and etch-polished with concentrated H₂SO₄ + H₂O₂, and immersed in IN KOH. The Ga{111} faces were found to be the most noble with respect to rest and anodic dissolution potentials. The potential difference between the inverse {111} faces was as large as 0.14v for the rest and 0.123v for the dissolution potentials. The …

Analysis And Synthesis Of Highway Pavement Design, Thomas R. Buick

JTRP Technical Reports

No abstract provided.

Economic Model For The Maintenance Of Traffic Signals: Technical Paper, Thorold G. Smith, Joseph C. Oppenlander

JTRP Technical Reports

No abstract provided.

Fortran Iv Programs To Develop Contour Maps Of 3-Dimensional Data : Progress Report, A. Keith Turner

JTRP Technical Reports

No abstract provided.

An Informational Manual On The Urban Transportation Planning Process For Technical Committees In Smaller Urban Areas : Progress Report, Ronald Jerome Hensen, William Louise Grecco

JTRP Technical Reports

No abstract provided.

Small Scale Reinforced Concrete Models, Robert C. Vansiclen

JTRP Technical Reports

No abstract provided.

Pore Studies Of Carbonate Aggregates By An Evaporation Technique : Informational Report, Harold Reid Brown

JTRP Technical Reports

No abstract provided.

Fracture Of Hardened Cement Paste, Steven John Hanna

JTRP Technical Reports

No abstract provided.

The Response Of Bituminous Mixtures To Dynamic And Static Loads Using Transfer Functions, S. A. Swami

JTRP Technical Reports

No abstract provided.

A Simplified Procedure For Major Thoroughfares Planning In Small Urban Areas : Progress Report, David Kent French

JTRP Technical Reports

No abstract provided.

Thermal Runaway In Power Transistors, Jerry H. Lee

Masters Theses

"Considerable work has been done on the theory of thermal runaway and the relationship between transistor junction temperature and collector power dissipation. The first part of this thesis is a review of literature. An equation for the normalized junction temperature and its peak value is developed. From this equation, the junction temperature at the thermal runaway point for a given maximum power dissipation could be determined. The second part of this thesis is experimental. The author examined the thermal runaway points for eight different transistors in the basic common emitter class A circuit which operated under no signal DC conditions"--Abstract, …

Urban Geology—A Need And A Challenge, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Urban land uses are rapidly converting open land into intensively used land. Generally, in planning those uses, a comprehensive study has included everything except an evaluation of the land in three dimensions. Geologists are eminently well equipped to supply the missing data, but they must also be aware of the needs of the urban community and the kinds of information needed by planners if they are to write reports usable by planners. Urban and environmental geology is a newly expanding field in the use of geologic data to help solve some urban problems in the planning stage. It is likely …

A Simple Design Algorithm For Synthesis Of Multilevel Combinational Networks, James H. Tracey

Electrical and Computer Engineering Faculty Research & Creative Works

An algorithm is presented for the synthesis of combinational networks with a constrained arrangement of ANDS, ORS, NANDS, NORS, and inverters. The algorithm is easily presented to students in an introductory logic design course and has considerable application in modern practical logic design. Many texts available for a first course in logic design give very limited practical guidance for synthesis of networks under constraints outlined here. It is suggested that the algorithm presented here be furnished as supplementary material in the introductory course. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.

Neutron Radiation Damage In Silicon Transistors, C. A. Goben, F. M. Smits, J. L. Wirth

Electrical and Computer Engineering Faculty Research & Creative Works

In the investigation of base and collector current as a function of the emitter-to-base voltage, previous studies have shown that neutron-induced base current has components originating in the emitter space charge region as well as the neutral base region. This study shows that while the low injection level neutron-induced base current is dominated by the space charge component, the high injection behavior appears to be controlled by recombination in the neutral base region. Additional experiments performed in special tetrode transistors and van der Pauw-type samples indicate that changes in collector current are dominated by recombination in the neutral base, while …

Design Of Truncated Sequential Tests For Rapidly Fading Radar Targets, Norval D. Wallace

Electrical and Computer Engineering Faculty Research & Creative Works

Curves and equations are presented from which the exact performance of truncated sequential tests can be determined for one important case: the biased square-law detector for the detection of rapidly fading targets. The method of generating functions is used to derive probability distributions for sample size. It is shown how these probability distributions can be used to determine truncation errors and the effects of multiple-resolution elements. Sample calculations are performed to determine the effects of a particular truncation procedure. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.

Training Needs For Metal Tradesmen In Iowa, Harlan E. Giese

Dissertations and Theses @ UNI

This study was undertaken to assist area schools and the State Board of Public Instruction by identifying the industrial training needs for semi-skilled and skilled metal tradesmen.

One of the problems confronting the administrators of the area community colleges, vocational schools, and high schools in Iowa is that of identifying the industrial training needs of manufacturers and business firms in the state. This need identification is necessary so that students trained in occupational curricula in the area-community colleges and vocational schools, and local high schools will find jobs available in their field of specialization when they graduate.

The area schools …

The Identification And Evaluation Of Toxic Effects Of Organic Micropollutants, John Warren Smith

Doctoral Dissertations

No abstract provided.

Film Boiling Of Nitrogen From A Spherical Heating Surface At Atmospheric Pressure And Standard Gravity, Juan Jorge MariáNyi

Masters Theses

"A steady state film boiling heat transfer study was conducted at atmospheric pressure, with a heated sphere as the heat transfer surface and liquid nitrogen as the boiling medium. Results indicate that the heat transfer rate in film boiling is not the same around the sphere. For the same heat flux, heat transfer at the sides of the sphere takes place at higher temperatures than at the bottom of the sphere. The data were compared with the equation of Frederking and Clark for spheres (1̲8̲), which was derived to predict steady state conditions at standard, fractional and near zero gravity. …

A Study Of A Model-Referenced Adaptive Control System, James William Graham

Masters Theses

"A model-referenced adaptive controller for a first-order plant with time-varying parameters is developed using Lyapunov's second method. The system is studied with the aid of analogue computer simulation and an oscillatory mode is encountered. A method of reducing the oscillations by addition of a compensating network is proposed. The compensation is obtained through the use of linearization and root locus techniques. The compensated system shows a much improved error response over the original system"--Abstract, page ii.

Transient Response Of A Class Of Distributed Systems, Jaw-Shyong Tzeng

Masters Theses

"The transient response of uniform distributed systems with any transfer function that is rational in w=e[square root of Ts] can be analyzed with the basic form of the transfer function [1 over (w-a)] after partial fraction expansion, where the pole a can be real or complex in the w plane. with the complex pole within the stable region in the w plane, there are only two possible combinations of the basic transfer function [1 over (w-a)], i.e. [1 over (w-a)] ł [1 over (w-a*)], for physical realizability. The imaginary part of the transient response of the basic transfer function [1 …

A Comparison Of Proportional And Nonproportional Damping In Multistory Shear Buildings, Edwin C. Bailey

Masters Theses

"The purpose of this study was to determine whether proportional damping could be used to satisfactorily simulate the more practical nonproportional damping condition in multistory shear buildings. To accomplish this one computer program was written to analyze proportionally damped systems and another to analyze nonproportionally damped systems, each giving as output the frequencies, mode shapes, displacements, shears and moments and the maximum shears and moments. Shear buildings of two, three and four stories were studied in which the damping coefficients were varied from one to ten percent of critical damping. Although the programs could handle various other types, only linearly …

Thixotropic Effects In A Clay-Water System, John Arthur Mathes

Masters Theses

"Fundamental aspects of thixotropic phenomena are described, and previous investigations of thixotropic behavior in soil systems are summarized. The complex nature of the thixotropic phenomena as well as its general occurrence in fine grained soils is described. As existing hypothesis for thixotropic behavior based on initial non-equilibrium conditions is examined. Experimental results, as determined from a testing program on the Putnam clay, verify this hypothesis. The rate and magnitude of thixotropic strength increases of the Putnam clay were determined. Shear strength determinations were made by the unconfined compression and laboratory vane shear tests. The results of the tests were compared …

An Ultrasonic Pulse Generator Using The Transducer As A Frequency Determining Element, Donald E. Watke

Masters Theses

"This paper describes the development of a method of ultrasonic pulse generation in which the transducer determines the frequency of oscillation. A definite advantage of this method is the ability of the frequency of oscillation to change with changes in the transducer mechanical resonant frequency. This maintains peak efficiency at all times. The method is demonstrated in a small sonar transmitter but could be applied to any area involving driven ultrasonic transducers"--Abstract, page ii.

An Analysis Of Dirac Delta Generated Spherical Waves In An Infinite Maxwell Medium, William F. Breig

Masters Theses

"It is an accepted fact that the simple Maxwell and Voigt models do not usually represent the behavior of real materials. In order to make the results of a model more realistic, other combinations of springs and dashpots must be considered. To understand the more complicated models, it is desirable to have a knowledge of the Maxwell model since this element usually occurs either in series or in parallel in the advanced models. This investigation reports solutions of the spherical wave equation in both the elastic and viscoelastic media. Laplace transform techniques are used to obtain the parameters; stress, velocity, …

Synchronization Of Pulse Code Modulation Telemetry, Lawrence J. Mueller

Masters Theses

"Pulse Code Modulation (PCM) is one of the most widely utilized radio telemetry techniques for the recovery of test data from aerospace vehicles. Synchronization of the receiver with the transmitted data is perhaps the prime requisite of a PCM telemetry system. In this paper the frame synchronization process is analyzed by developing equations which define the three modes of synchronizer operation (SEARCH, VERIFY, and LOCK) in terms of the relative probabilities of operation. The criteria employed to optimize the synchronization process are the mean time to acquire true synchronization, the probability of true synchronization after verification of the synchronization decision, …

A Simulation Of The Transistor By Computer Using The Linvill Diffusion Model, Clifford D. Skouby

Masters Theses

"This investigation involves the construction of an analog computer model of the transistor. The computer model is based upon the Linvill diffusion model. The equations for the Linvill diffusion model were programmed on the computer by making certain approximations. Different models, using different approximations, were used for the different regions of operation of the transistor. A composite analog model was constructed by combining the models for the restricted regions, giving a general model good for all regions of transistor operation. This analog diffusion model was modified to account for the effects of junction capacitance and base resistance. The modified analog …

Electric Field Investigations And A Model Of Electrical Spraying Of Liquids, Wallace Deshon

Masters Theses

"The equation E = [2 V] [over] [N 1n(4d/N] has been used for determining the electric field at the liquid tip in electrical spraying of liquids. Data were taken at the instant of spraying in an attempt to experimentally verify this equation. The results indicate that the value given by the equation needs to be increased by about 20% in the normal range of operation. A model for the spraying mechanism of the liquid is also proposed"--Abstract, page ii.

Computer Simulation Of Scraper-Pusher Behavior During Early Open Pit Mining Operations, Martin Alan Thieme

Masters Theses

"A method has been developed for study and evaluation of overburden removal systems in open pit mining. The computer simulation method shows the effect of vehicle and course characteristics and the control of loading time on overall production and cost per unit of overburden removed. Data are available from vehicle manufacturers and from past mining experience. The data are punched onto processing cards and the system is then simulated and analyzed using a digital computer. The products of the system simulation consist of a tabulated listing of all control variables after each simulated vehicle loading and a system summary predicting …

Recombination Statistics For Neutron Bombarded Silicon Transistors, M. C. Chow, J. L. Azarewiczt, C. A. Goben

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a recombination statistical model for the neutron-induced base current component reported previously. The derivation was based on the following: 1) the current equation for the induced current component developed previously; 2) the Shockley-Read-Hall statistics for holes and electrons; and 3) the recombination statistics derived by Sah, Noyce and Shockley for sites in the bulk space-charge region. The recombination statistics model depends on the diffusion potential, the junction voltage, the activation energy, temperature, and the ratio of capture cross-sections for holes and electrons. The utility of such a recombination statistical model is illustrated by using measured parameters to …

Heat Transfer Between A Turbulent Round Jet And A Segmented Flat Plate Perpendicular To It, John Edward Chamberlain

Theses

Heat transfer between a room temperature, turbulent round jet and a segmented flat plate perpendicular to it has been investigated.

The heat transfer surface consisted of invar rings insulated from each other with silicone rubber. The source of heat was steam at atmospheric pressure condensing on the back of the heat transfer surface.

Since data were taken over a wide range of vertical distances between the nozzle and the flat surface both the potential cone and the fully developed regions of the jet were observed interacting with the heated plate.

It was determined that two modes of heat transfer occur; …