Engineering Commons^™

The Effect Of Transient Ionizing Radiation Upon Schottky Barrier Diodes, Robert H. Schnurr

Electrical and Computer Engineering ETDs

The theory of operation of the Schottky barrier diode was reviewed. The complications caused by a more accurate space charge formulation were discussed. Consideration of image effects, tunneling, interfacial dielectric layers, surface states, and minority carrier current was also included.

The interaction of ionizing radiation with semiconducting materials was reviewed. The behavior of a Schottky barrier diode in an ionizing radiation environment was considered. The resultant model for the Schottky barrier diode is analogous to a p-n diode with one side having a very high dopant concentration.

Tests were performed upon GaAs and silicon Schottky barrier diodes, using a 2 …

Analysis Of Traffic Loads On Bridges, Robert L. Lynch

Kentucky Transportation Center Research Report

This report contains information concerning:

1. The statistical determination of frequencies of critical axle loadings on highway bridges and
2. The adaptability and adaptability of historical loadometer and classification data in Kentucky to the recently adopted AASHO design criteria for evaluating the fatigue history of existing bridges.

The analysis of the fatigue history of a bridge consists of evaluating the distribution of instantaneous axle loadings over the applicable period. Because of the urgency, only historical records currently available were used as source data. This report is therefore divided into two sections: 1) a summary of quantitative results based on available data, and …

Construction And Interim Performance Report Of Experimental Salt (Nacl) Stabilization Of Plant-Mixed, Dense Graded Aggregate, Robert L. Florence

Kentucky Transportation Center Research Report

For some time the Department has been interested in building-up and retaining thicknesses of granular base course on rural roads through the use of various stabilizing additives and(or) the use of light asphalt seals or surfacings (1, 2, 3, 4, 5, 6). These efforts more or less recognize that the "stage construction" concept is frustrated by weather and traffic erosion of unbound and exposed granular base material. Thus, the motive in experimenting with and in utilizing these treatments is to find economical and effective means by which a granular base can be built and retained until such time that a …

The Dynamic Low Cycle Testing Machine: (Design And Calibration), Michael J. Shannon

Mechanical Engineering ETDs

The design and development of a loading device for subjecting a reversed shear specimen to a pulsed dynamic load is described. The development includes calibration technique to confirm that design criteria had been met. A relationship between plastic deformation and peak tensile load is presented.

Hq Amc Go 5, Missile Intelligence Directorate, Us Army Missile Command, Huntsville, Alabama, 19 January 1968., Headquarters Us Army Materiel Command, Robert Bolin , Depositor

United States Department of Defense Military Intelligence

This order established the Missile Intelligence Directorate (MID) as an intelligence agency assigned to the US Army Missile Command to “… develop, maintain, and disseminate foreign scientific and technical intelligence concerning ground forces, surface-to-surface, surface-to-air, and anti-ballistic missile systems in response to valid Department of Defense, Department of the Army, and Army Materiel Command production requirements.”

This order established the second intelligence production organization within the Army Materiel Command. The first being the US Army Foreign Science and Technology Center.

Specification For The Design Of Cold-Formed Steel Structural Members, American Iron And Steel Institute

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

No abstract provided.

Estimation Of Film Boiling Heat Transfer Coefficients For Cylindrical Heaters In Corresponding States Fluids, Gary Joseph Capone

Masters Theses

"An investigation of film boiling heat transfer was made with cylindrical heaters. The (0.75" O.D.) gold plated, copper heaters were positioned horizontally in pools of liquid argon, nitrogen, and carbon monoxide. A correlation for film boiling corresponding states fluids is derived and discussed. The correlation is a least squares fit of three variables: the diameter of the cylindrical heater, the reduced pressure of the system, and the temperature difference between the heater surface and the saturated pool"--Abstract, page iii.

Isotope Effect Of Interstitial Diffusion Of Carbon In A Dilute Fe-Si Alloy, Edward T. Yen

Masters Theses

"The isotope effect of carbon interstitial diffusion in a Fe-2.75at%Si alloy has been measured at -3.10°C using the disaccommodation technique. The disaccommodation has been analyzed in terms of two relaxation processes which are discussed on the basis of the reorientation mechanism of carbon interstitials at Fe-Fe sites and Fe-Si sites respectively. The ratios of the relaxation times [tau]₁₃/[tau]₁₂ are 1.0382 for the former and 1.0072 for the latter relaxation process. This result is discussed on the basis of many-body reaction rate theory"--Abstract, page ii.

Zener Disaccommodation In Dilute F.C.C. Co-Ti Alloys, H. B. Aaron, M. (Manfred) Wuttig, H. K. Birnbaum

Materials Science and Engineering Faculty Research & Creative Works

The magnetic Dis accommodation, i.e., the time dependence of the low field magnetic permeability, was investigated in cobalt base alloys containing 0-5.1 at.% (0-4.2 wt.%) titanium in the temperature range 400-700°C. A strong temperature dependence of the Dis accommodation observed in the range 430-530°C could be accounted for predominantly by a single first order relaxation process. Analyzing the data in terms of (a) a single exponential relaxation, (b) a lognormal distribution of relaxation times, and (c) a sum of exponential relaxations, it was shown that the relaxation strength varies as the square of the titanium concentration and that the relaxation …

West Midlands Development : Erosion Prevention And Control, G W. Spencer

Journal of the Department of Agriculture, Western Australia, Series 4

THE prevention of soil erosion is essentially a matter of using each soil according to its potential, and treating it according to its needs.

Good land use and sound management practices are the best preventive measures.

West Midlands Development : Development Techniques, Department Of Agriculture, Western Australia

Journal of the Department of Agriculture, Western Australia, Series 4

Most clearing in the West Midlands is carried out by chaining, though the method chosen will depend on the country being cleared and on the resources of the farmer.

Concrete In Dairies, D Roger Buchanan

Journal of the Department of Agriculture, Western Australia, Series 4

PRIME requirements for exposed concrete surfaces in dairies are that they should be easily cleansed and should not deteriorate in contact with milk and milk products.

In milking stalls, animal races and on loading platforms hardwearing surfaces which offer good foothold are also necessary.

The Damage Assessment Of Thermally Shocked High Density, High Purity Aluminum Oxide, John H. Ainsworth

Doctoral Dissertations

"The traditional approach to thermal shock testing in brittle materials has been to determine the temperature difference required to nucleate cracks in these materials. Recent work has indicated that the degree of damage after crack nucleation should be an additional consideration. The degree of damage resulting from cooling thermal shocks has been the primary consideration of the present work. Test specimens of two geometries: long, solid rods and short, solid cylinders were quenched from selected temperatures into ice water. The degree of damage was determined through strength measurements and sonic damping analysis. Initial damage occurred at a temperature difference above …

Hrva - A Velocity Analysis Technique For Seismic Data, John Charles Robinson

Doctoral Dissertations

"A High-Resolution Velocity Analysis (HRVA) has been developed for the determination of the root-mean-square subsurface-velocity energy spectrum from gated seismic data which has been normal-moveout corrected. All calculations are performed in the frequency-space or frequency-wavenumber domain; seismic gates are transformed from the time-space domain via the Fast Fourier Transform algorithm. HRVA is not restricted to the investigation of apparent horizontal velocities which have associated stepout values that are integral multiples of the time sampling interval, as are the existing correlation techniques. The technique liberally exploits the inexistence of significant energy in the higher frequency harmonies of seismic data, resulting in …

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

Doctoral Dissertations

No abstract provided.

Prediction Of Drag Reduction With A Viscoelastic Model, Gary Kent Patterson, J. L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

Numerical Differentiation Of Equally Spaced And Not Equally Spaced Experimental Data [3], Harry C. Hershey, Jacques L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

Transport Of ⁸⁵Sr And ¹³⁷Cs Under Induced Clay Suspensions, Purush Terkonda

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

“The purpose of this study was to evaluate the effect of induced clay suspensions on the transport of ⁸⁵Sr and ¹³⁷Cs in an aqueous environment.

An instrumented flume was used as a model river to simulate an environment typical of a slow-moving, unpolluted, turbid stream. Modified longitudinal dispersion relationships were used to describe the transport of radionuclides in turbid streams. Data were derived from instantaneous release of ⁸⁵Sr and ¹³⁷Cs with suspended Attapulgite and Kaolinite clays. Continuous release of ¹³⁷Cs with an Attapulgite clay suspension helped to establish uptake and transport characteristics for one environmental …

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 …

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 …

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.

A Direct Method Of Measuring Stray Load Loss In Dc Machines, Kanaiyalal R. Shah, George Mcpherson

Electrical and Computer Engineering Faculty Research & Creative Works

Stray load loss in dc machines is denned as the difference between the actual loss under load and the well-recognized loss. This paper describes a simple, reliable, and direct method of measuring this loss by means of a proposed short-circuit test with a correction factor for uncompensated-type dc machines. It also describes the sources and components of stray load losses as they occur under short-circuit test. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.

Radiation And Annealing Characteristics Of Neutron Bombarded Silicon Transistors, L. S. Su, G. E. Gassner, C. A. Goben

Electrical and Computer Engineering Faculty Research & Creative Works

Operating a silicon planar epitaxial transistor in the inverse configuration allows one to demonstrate clearly the importance of the neutron-induced base current component and its degradation of the emitter efficiency, and, because of the much larger depletion layer, to compute a volume dependent damage constant applicable to all silicon p-n junctions. The importance of minimizing the absolute change versus relative change in radiation hardening studies is clearly illustrated. Surface effects were found to be significant for transistors mounted in gas-filled cans. The diffusion potential was predicted, on theoretical grounds, to vary with neutron fluence, and the theory was experimentally confirmed. …

Waveform Distortion Caused By A Plasma Sheath, James R. Carl

Masters Theses

"A short burst of electromagnetic energy that propagates into and through a plasma medium can react with the plasma medium in several different ways depending on both the characteristics of the plasma and of the pulse. This thesis derives approximations for the plasma transfer function at low pressure (high altitude) and at high pressure (low altitude). The mechanisms that can change the shape of a waveform, in general, are dispersion and breakdown. dispersive distortion at low altitude is shown to exist for electron concentrations well above the resonant concentration for plasma sheaths that are thin compared to one wavelength. Several …

Influence Of Continuous Precipitation Upon The Growth Kinetics Of The Cellular Reaction In An Al-Ag Alloy, H. I. Aaronson, J. B. Clark

Materials Science and Engineering Faculty Research & Creative Works

The influence of the prior formation of a continuous precipitate upon the growth kinetics of the cellular reaction has been evaluated in an Al-17.9 wt. % Ag alloy. The continuous precipitate, in the form of intragranular plates of the γ′ transition phase, was shown to have reduced the upper bound of the driving force for the cellular reaction from the silver content of the untransformed alloy to that corresponding to the coherent solvus. When this reduction (≥ 98 %) is taken into account, the growth of cells is found to be controlled by cell boundary rather than by volume diffusion …

Age Hardening In A Mg-9 Wt.% Al Alloy, J. Beverley Clark

Materials Science and Engineering Faculty Research & Creative Works

The precipitation process and age hardening mechanism in a Mg-9 wt.% Al alloy were studied principally by transmission electron microscopy. This alloy age hardens by the general precipitation of plates of the equilibrium Mg₁₇Al₁₂ phase on the basal plane of the magnesium solid solution matrix. No evidence for the formation of either G.P. zones or a transition lattice of the Mg₁₇Al₁₂ precipitate was obtained. Cellular precipitation occurs competitively with the general precipitation at nearly all age hardening temperatures. In the solution treated condition, basal slip and {101̄2} twins are the principal deformation modes. Precipitation …

Application Of Stanford Watershed Model Concepts To Predict Flood Peaks For Small Drainage Areas, K. D. Clarke

Kentucky Transportation Center Research Report

This report embodies two principal objectives: 1) updating rainfall intensity-duration curves for the hydraulic design of culverts and 2) adaptation of the Stanford Watershed Model concept to small drainage basins in Kentucky. The first objective is familiar -- the curves presently being used for the rational method of design were established from an earlier Department study made by E. M. West and W. H. Sammons, issued in July, 1955 (Report No. 2, "A Study of Runoff from Small Drainage Areas and the Openings in Attendant Drainage Structures"), and were based on rainfall records then available through 1951. The second objective …

Water Quality Telemetry First Annual Progress Report, Duard S. Woffinden, Allen D. Kartchner

Reports

No abstract provided.

Feasibility Of Rating Current Meters In A Velocity Field, Gaylord V. Skogerboe, Lloyd H. Austin, Roland W. Jeppson, Chi-Yuan Wei

Reports

Preliminary studies employed an 8-inch (outlet diameter) contracting cone and an 8-inch converging nozzle. The design of the cone is based on an electromagnetic analogy reported by Smith and Wang, while the nozzle was designed assuming potential flow and using numerical methods to obtain the solution. Both designs yielded fairly uniform velocity fields, any deviations being primarily due to either construction or measurement techniques. The towing tank rating for a Pygmy current meter was compared with the submerged jet rating, the difference being 1 or 2 percent. A Prototype system was constructed using a 16-inch contracting cone (d). Two Type …

Hydraulic Characteristics Of A Modified Venturi Section, Muhammad Aslam Rasheed

Reports

The measurement of water in open channels on extremely flat grades is difficult because of the head loss that is necessary. A modified venture section, the contraction of which is provided by a top cover section mounted in a rectangular flume, is proposed to meet the requirements of a suitable measuring device for use in canals of flat gradients. The method of finite differences has been used for the mathematical solution to the idealized inviscid flow problem. This was followed by a laboratory investigation to ascertain the hydraulic characteristics of the proposed design. The experiments were conducted in a 3 …