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Articles 190471 - 190500 of 196433

Full-Text Articles in Engineering

Bridge Paint Specifications, Proposed Revisions, James H. Havens Jun 1968

Bridge Paint Specifications, Proposed Revisions, James H. Havens

Kentucky Transportation Center Research Report

During the past several years, I have devoted considerable attention and study to bridge-paint systems and specification -- in an attempt to keep abreast with developments and current practices throughout the country. My first proposal (July 30, 1958; copy appended) was motivated by development of a then-new rust-inhibitive pigment suggested by National Lead Company. The pigment had shown considerable promise as a substitute for red lead and appeared in many respects to be superior to red lead -- on of which was economy.


Construction And Performance Of Trial Section Of Treated Shoulders On The Mountain Parkway Extension, Robert L. Florence, Tommy C. Hopkins Jun 1968

Construction And Performance Of Trial Section Of Treated Shoulders On The Mountain Parkway Extension, Robert L. Florence, Tommy C. Hopkins

Kentucky Transportation Center Research Report

In October 1966, J.W. Spurrier, Assistant Operations Management Engineer, requested that the Research Division make a study of a two-mile section of the shoulders on the Mountain Parkway Extension in Wolfe County (from Mile Post 43.8 to Mile Post 45.8) and make recommendations for design and construction procedures for cement stabilization of the shoulders. In compliance with this request, in January 1967, Research Division personnel made a survey of the full length of shoulder on the Mountain Parkway Extension. Included in this survey were measurements of depth of the dense graded aggregate, penetrations of the shoulder subgrade soil and samples …


Investigation Of Use Of Preformed, Compressed Neoprene Seals In Joints Of Concrete Bridge Decks, Dennis L. Willaman Jun 1968

Investigation Of Use Of Preformed, Compressed Neoprene Seals In Joints Of Concrete Bridge Decks, Dennis L. Willaman

Kentucky Transportation Center Research Report

Progressive deterioration and staining of concrete bridge substructures and erosion of abutments may, in many instances, be attributed to the leakage of bridge deck joints. The primary difficulty in maintaining a properly sealed joint is the continual expansion and contraction of the bridge spans. Joint seals, of course, must remain in contact with both faces of the disjointed sections and remain flexible at all temperatures encountered.

A study was initiated by the Division of Research for the specific purpose of evaluating the performance of preformed, compressed neoprene seals and to compare the performance of these seals with the performance of …


The Development Of An Instrument For Three Dimensional Analysis Of Micron Quantities Of Tooth Movement, M. Clark Lamberton Jun 1968

The Development Of An Instrument For Three Dimensional Analysis Of Micron Quantities Of Tooth Movement, M. Clark Lamberton

Loma Linda University Electronic Theses, Dissertations & Projects

In order to quantitate initial tooth movement in response to forces applied to the tooth crown, an instrument for intraoral use has been developed. The photomicrometer consists of nine photosensitive cells mounted in an assembly of two layers. Eight of the cells were mounted to form X and Y axes, top layer and bottom layer, to measure horizontal movements. The ninth cell was mounted in the center of the bottom layer and was used for alignment and for measurements in the Z or vertical axis. The photocell assembly was approximately 10 mm diameter and 6 mm high. This assembly when …


X-Ray Irradiation Studies Of Lybian Desert Glass And Sand, Magdi M. Nasrallah Jun 1968

X-Ray Irradiation Studies Of Lybian Desert Glass And Sand, Magdi M. Nasrallah

Archived Theses and Dissertations

No abstract provided.


Design Of Linear Control Systems With Distributed Parameter Elements By Parameter Plane Techniques, Murray Weinberg May 1968

Design Of Linear Control Systems With Distributed Parameter Elements By Parameter Plane Techniques, Murray Weinberg

Dissertations

This dissertation extends the application of parameter plane techniques to a number of areas. Specifically, the parameter plane technique can now be used to determine absolute stability, relative stability, and the location of roots of the closed-loop characteristic equation of systems containing both lumped and distributed parameter elements. The advantages of utilizing this technique are that results can be obtained as two system parameters are varied simultaneously and higher order systems can be treated as easily as low order ones.

Investigation of the mapping of real roots resulted in the derivation of a theorem which relates the number of real …


Noise Spectral Density As A Diagnostic Tool For Reliability Of P-N Junctions, Young Duck Kim May 1968

Noise Spectral Density As A Diagnostic Tool For Reliability Of P-N Junctions, Young Duck Kim

Dissertations

The feasibility of choosing noise-voltage spectral density as a prediction parameter for the degradation of p-n junctions has been examined both theoretically and through a series of life-tests.

Experimental facts show that the noise-voltage spectral density, Sv(w), observed in a p-n junction under the breakdown condition tends to be "white" (which contradicts the 1/f-noise theory), and Sv(w) is inversely proportional to the breakdown current (which contradicts the shot-noise theory). Furthermore, some p-n junctions display one or more multiple peaks of Sv(w) at different current levels which can not be explained by any of the …


An Analysis Of The Effects Of Ionizing Radiation In One-Dimensional Metal-Oxide-Semiconductor Structures, Charles William Gwyn May 1968

An Analysis Of The Effects Of Ionizing Radiation In One-Dimensional Metal-Oxide-Semiconductor Structures, Charles William Gwyn

Electrical and Computer Engineering ETDs

Previous investigations of the radiation effects in Metal­Oxide-Semiconductor (MOS) devices have shown that ionizing radiation produces a trapped space charge in the oxide which causes a shift in the electrical characteristics of the device. Several models have been proposed to explain the observed change in the MOS device characteristics as a function of nuclear radiation exposure. Although these models have qualitatively explained the change in device characteristics, they have not adequately explained the physical processes producing the charge buildup nor have they considered the detailed conduction and charge trapping processes which exist in the various regions of an MOS structure. …


Magnetic Control Of Carrier Concentration In Semiconductors, S. Lee Hight May 1968

Magnetic Control Of Carrier Concentration In Semiconductors, S. Lee Hight

Electrical and Computer Engineering ETDs

Magnetic control of carrier lifetime in semiconductors has been examined from a standpoint of applying this phenomenon to low-voltage, high-current switching devices. The continuity equation is extensively examined for intrinsic semiconductors, and limits are derived on the magnitude of the switching effects in terms of material parameters. Experiments have been conducted on undoped indium antimonide which tend to verify these limits. A cursory examination is made of the control of the lifetime of injected carriers. The indications are that this effect may be useful in a wider range of materials than the effect in intrinsic semiconductors.


Electromagnetic Scattering From A Statistically Rough Spherical Surface With Shadowing, James Albert Doran May 1968

Electromagnetic Scattering From A Statistically Rough Spherical Surface With Shadowing, James Albert Doran

Electrical and Computer Engineering ETDs

Significant errors may be introduced into the theoretical calculation of scattered fields from a roughened sphere by the use of erroneously derived shadowing probabilities. These shadowing probabilities, of recent appearance in the literature, had been derived using an infinite plane as the mean surface. This paper undertakes the derivation of shadowing probabilities using a spherical mean surface. Although closed form expressions could not be obtained, computer evaluation of a "correction factor" showed that the errors incurred through use of the infinite plane probabilities (rather than the spherical surface) are insignificant. The class of rough surfaces considered was with a gaussian …


Measurement Of Deformations An A Large Displacement Gradient Field, Lowell P. Martin May 1968

Measurement Of Deformations An A Large Displacement Gradient Field, Lowell P. Martin

Mechanical Engineering ETDs

A summary of the general kinematical theory of finite deformations is presented together with analyses of the specific deformations of sim­ple shear, bending of a block and bending of an initially curved cuboid.

The moiré fringe equations for large homogeneous deformation are developed. The extension to the nonhomogeneous case is presented and specific analyses are given for the deformations noted above. The moiré theory is combined with the results of the large deformation analyses.

Theoretical results are verified by the study of geometrically produced moiré patterns, and by actual experiments conducted on syn­thetic rubber specimens. The experiments included the deformations …


Liquid Vapor Equilibrium In Nucleate And Film Boiling, Walter Henry Rothaug May 1968

Liquid Vapor Equilibrium In Nucleate And Film Boiling, Walter Henry Rothaug

Theses

Liquid vapor equilibrium data were obtained for several solutions and azeotropes under both nucleate and film boiling. The data were invariant between the two boiling regimes indicating that both nucleate and film boiling are equilibrium vaporizations rather than either diffusional or bulk vaporizations. Boiling heat transfer versus temperature data were taken in nucleate and film boiling for the solutions and azeotropes and for several pure liquids. The critical heat flux for methyl alcohol-benzene solutions rose sharply at first and then more moderately with increasing alcohol concentration. The critical heat flux was pratically constant regardless of concentration in ethyl alcohol-benzene solutions. …


Coagulation In Waste Water Treatment, Garret P. Westerhoff May 1968

Coagulation In Waste Water Treatment, Garret P. Westerhoff

Theses

This paper emphasizes a practical approach to the coagulation of domestic waste water. A portion of the paper is a synopsis of current published literature on the subject. Laboratory studies on the coagulation of raw domestic waste waters were conducted to provide the basis of a practical procedure for the evaluation and design of a coagulation process. Studies included the development of a relationship between the B.O.D. and the soluble and solids portion of two waste tests. The jar test was used for the studies on the coagulation process. The final section of the paper outlines the chemical cost factors …


The Effect Of Internal Combustion Engine Operation Upon The Viscometric Properties Of Polymer Thickened Multi-Viscosity Crankcase Oils, William Charles Philcox May 1968

The Effect Of Internal Combustion Engine Operation Upon The Viscometric Properties Of Polymer Thickened Multi-Viscosity Crankcase Oils, William Charles Philcox

Theses

The effects of engine mileage upon the viscometric properties of seven different brands of multi-viscosity engine oils were examined by subjecting each brand of oil to an average of 1500 miles of service in the crankcases of different passenger cars.

Oil samples were taken every 500 miles after the oil was put in the crankcase. The control oil sample was taken from a can of oil at the time the oil was put in the engine.

The viscosity indices and kinematic viscosities at 100° F and 210° F were calculated for each sample of oil. The percent change in viscosity …


The Effects Of Air-Water Two Phase Flow On The Performance Of A Centrifugal Pump, Karnig Ekizian May 1968

The Effects Of Air-Water Two Phase Flow On The Performance Of A Centrifugal Pump, Karnig Ekizian

Theses

This study investigates the performance of a 1-inch long 4-vane open impeller centrifugal pump under two phase flow conditions. The paddle wheel pump, as branded by its manufacturer the Worthington Corporation, had a specific speed of 3400 (based on gallons per minute, feet of water and revolutions per minute) corresponding to a 7-inch impeller diameter. A 1/8-inch perforated steel pipe carried the compressed air to within four inches of the impeller eye where the air was injected into the water stream (See figures 18 and 20).

The three variable inputs were, water flow rate, pump speed and air flow rate. …


A Study Of The Properties Of The Biconical Antenna, Kurt Frank Hafner Jr. May 1968

A Study Of The Properties Of The Biconical Antenna, Kurt Frank Hafner Jr.

Theses

Expressions are found for the fields produced by TM and TEM modes along a finitely conducting biconical antenna. Expressions are also found for the TM and TEM fileds along a biconical antenna having a lossy dielectric coating. It is shown that the antenna losses produce an anntenuation of the the fields along the antenna. It is found that because there is a dispersion of the fields along the biconical antenna, the attenuation produced by the losses is, in genaral, not characterized by simple exponential.

A solution is obtained for the fields of the TEM wave along a biconical antenna coated …


Reliability Considerations For Communication Satellites, Frank Polizzi May 1968

Reliability Considerations For Communication Satellites, Frank Polizzi

Theses

A detailed program covering all phases of reliability for a communication satellite was presented. In long mission programs such as this one, reliability is the prime consideration in assuring a successful accomplishment of the stringent goals set forth. Reliability principles and methods were incorporated in delineating each major task in the program. These principles and methods not only aided the reliability personnel in performing their duties better, but also assisted the design group, manufacturing personnel, and the testing and evaluation group in performing their jobs efficiently by being aware and knowledgeable of reliability engineering.

Various reliability disciplines were imposed, as …


Fault Protection With A Digital Computer, George D. Rockefeller May 1968

Fault Protection With A Digital Computer, George D. Rockefeller

Theses

A fundamental basis has been developed for the use of a time-shared stored-program digital computer to perform many of the electrical power-system protective-relay functions in a substation. Logic operations are given to detect a fault, locate it and initiate the opening of the appropriate circuit breakers, whether the fault is in the station or on lines radiating from the station.

The instantaneous value of the station voltages and currents are sampled at a 0.5 ms rate, converted to digital form and stored for computer main-frame use. Operating times are compatible with the 25 ms breaker trip capability of modern two-cycle …


Response Of A Nonlinear System To Random Vibration, James Darrell Gibson May 1968

Response Of A Nonlinear System To Random Vibration, James Darrell Gibson

Mechanical Engineering ETDs

Response statistics are obtained for a nonlinear, single-degree-of-freedom system subjected to a Gaussian, white noise random excitation. The system has nonlinear damping as well as nonlinear stiffness. The stationary joint probability density function is obtained as the numerical solution to the appropriate Fokker-Planck equation for the nonlinear system being considered. The first order probability density function, the mean square displacement, the average frequency of the response, and the average number of crossings of an arbitrary displacement level are subsequently obtained. These response statistics are compared with those obtained experimentally by simulating the nonlinear system under investigation on a solid state …


Test 977: David Brown Selectamatic 990 (Diesel), Nebraska Tractor Test Lab May 1968

Test 977: David Brown Selectamatic 990 (Diesel), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …


Stress Fluid In The Vicinity Of A Crack, Alfred S. Arcache May 1968

Stress Fluid In The Vicinity Of A Crack, Alfred S. Arcache

Mechanical Engineering ETDs

The purpose of this investigation was to apply the logarithmic hypothesis of the plane elastic dislocation theory to approximate a plane fracture problem. The region of study is essentially elastic except for a very small region in the neighborhood of the crack which is at some undefined plastic state. The model is a large, thin plate, tensile specimen bounded at the interior by a circular hole from which two stable natural cracks are originated. The experimental model was developed by Ju and Shafer, who also obtained the dislocation function along the crack used in the analysis.

The present fracture analysis …


Test 976: David Brown Selectamatic 1200 (Diesel), Nebraska Tractor Test Lab May 1968

Test 976: David Brown Selectamatic 1200 (Diesel), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …


Low-Cycle Fatigue Damage In Structures Subjected To Earthquake Excitation., Iyadurai Kasiraj May 1968

Low-Cycle Fatigue Damage In Structures Subjected To Earthquake Excitation., Iyadurai Kasiraj

Civil Engineering ETDs

The object of this investigation is to ascertain the possibility of having low-cycle fatigue failure of structures resulting from earthquake loads. In addition, a comparison is made between criteria of failure for maximum displacement and low-cycle fatigue.

The relationship between applied load, deflection and maximum strain in a shear type simple frame with rectangular columns have been analyzed for reversals of loadings. Two interrelated hysteresis loops, namely load-maximum strain curve and deflection-maximum strain curve, are proposed to give the upper-bound safety of the structure having columns with an average wide-flange (WF) section. These hysteresis loops are utilized for finding the …


Trends Of Suspended Sediments In The Upper Rio Grande Basin In New Mexico., Vernon W. Norman May 1968

Trends Of Suspended Sediments In The Upper Rio Grande Basin In New Mexico., Vernon W. Norman

Civil Engineering ETDs

Man has been troubled by the sediment in streams for many thousands of years. Any information toward understanding the nature of this sediment should benefit man in his endeavor to cope with it. Available information was used to determine if trends in the annual quantities of suspended sediment exist in the Upper Rio Grande Bas in in New Mexico. The study revealed that trends do exist and quantitative values were determined for the different trend periods. An effort was made to determine the most probable cause or causes for the changes that occurred in the trends. Eighteen years of suspended …


Test 975: Minneapolis-Moline G1000 Vista (Lpg), Nebraska Tractor Test Lab May 1968

Test 975: Minneapolis-Moline G1000 Vista (Lpg), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …


A Technique For Determining Transistor Spall Thresholds., Herbert L. Floyd Jr. May 1968

A Technique For Determining Transistor Spall Thresholds., Herbert L. Floyd Jr.

Electrical and Computer Engineering ETDs

ABSTRACT

The purpose of the work described in this report was to develop a technique for determining the mechanical robustness of small electronic components when subjected to short duration stress waves. Techniques employed by other experimenters., which include flyer­plate impaction and pulsed-electron deposition., are difficult to control and to analyze. The procedure described herein overcomes these difficulties by restricting the variables that control accuracy to those which can be precisely measured.

The wave equation was derived and solved for deformable bodies subjected to unidimensional strain. In addition to providing insight into the dependence of high-tensile stress es on stress -wave …


Test 974: Minneapolis-Moline G1000 Vista (Diesel), Nebraska Tractor Test Lab May 1968

Test 974: Minneapolis-Moline G1000 Vista (Diesel), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …


Test 973: Ford 8000 (Diesel), Nebraska Tractor Test Lab May 1968

Test 973: Ford 8000 (Diesel), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …


Investigation Of Implicit Methods For Solution Of The Fourier Equation, Kjell Steinar Gundersen May 1968

Investigation Of Implicit Methods For Solution Of The Fourier Equation, Kjell Steinar Gundersen

Theses and Dissertations

In recent years there has been an extensive development of finite difference techniques for solution of the transient heat conduction equation due to the availability of high-speed digital computers. It is the purpose of this paper to investigate and compare several implicit methods for the solution of the Fourier equation with regards to truncation error, round-off error and computer time which probably are among the most important factors to be considered in choosing a method.


Hot-Mix Coal-Tar Concrete Pavement And Multiple, Coal-Tar Seals On Shoulders, Robert L. Florence May 1968

Hot-Mix Coal-Tar Concrete Pavement And Multiple, Coal-Tar Seals On Shoulders, Robert L. Florence

Kentucky Transportation Center Research Report

It is proposed to construct an experimental section of roadway, 6.6 miles in length, using coal-tar concrete for base and surface, and to use multiple, coal-tar seals (3 seals) with coverstone on the shoulders. A section of pavement, 5.1 miles in length, incorporating the same structural thicknesses and types of courses but containing normal asphaltic binders, to be constructed on the same route will be designated for comparison and control purposes. The use of the coal-tar will be in compliance with Section 201(e) of the Appalachian Regional Development Acts of 1965.