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A Soil Stress Gage Evaluation., Caryl Martin Reiff

Civil Engineering ETDs

The static evaluation of a recently developed soil-stress gage, primarily designed for laboratory use in dry cohesionless soils, is presented. Two variations of the same basic soil stress gage design are discussed. Tests were performed to evaluate the gage linearity, temperature sensitivity, and electrical response to applied soil pressure. The gage responded linearly to pressure and the calibration curves remained stable within ± 5 percent over a period of two years. With a 10 ma bridge current, the gage had an output sensitivity of 0.040 mv per psi. Temperature changes produced signals which could not be distinguished from pressure signals. …

A Study Of Delta Modulation And Its Application To Control Communication, Robert H. Maschhoff

Electrical and Computer Engineering ETDs

This thesis is a study of certain aspects of delta modulation which are of particular interest or significance in control system communication. Delta Modulation is a discrete difference encoding method in which the amplitude difference between the signals occurring at two points in time can be transmitted as a plus one or a minus one bit. Such a method of encoding has a rate of change capacity limit rather than a hard amplitude bound.

A determination of the sampling rates, and therefore bit rates, necess­ary to encode several types of signals is reported. Signals which themselves have a rate-limited characteristic …

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 …

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. …

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 …

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.

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 …

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 …

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 …

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 …

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 …

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 …

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.

An Experimental Study Of The Effects Of Welding On Cold-Worked And On Heat-Treated Steels As They Correlate To Tempering And Jominy Data, Kiran Patwari

Theses and Dissertations

Since Bernandos of Russia in 1887 applied an electric arc to weld metals, welding has become an important method of fabrication in industry. The ever increasing use of welding on a still widening variety of materials demands m ore and m ore understanding of the basic mechanisms of welding.

Transition From Laminar To Turbulent Flow For Dilute Guar Gum Solutions, Martin L. Palmer

Theses and Dissertations

Solutions of many natural and synthetic polymers have been found to reduce turbulent friction losses in flow through pipes. The basic mechanism causing these reductions is not entirely understood although two general theories have been advanced.

Design Of An Automatically Controlled-Feed, Constant Current Arc Generating Machine For Consumable Electrodes, Dhansukh J. Chauhan

Theses and Dissertations

Good welding research requires accurate control of the variables involved,to achieve consistent results. The variables involved in arc welding are of the dependent and independent type. Control of the independent variables such as arc current, arc voltage and welding velocity is necessary to control the independent variables such as penetration, electrode consumption rate, etc. The purpose of this thesis was to design, develop and test an automatic welding machine which controlled the above variables within the limits required for welding research.

Design Of An Apparatus For Study Of Stress Versus Strain As A Function Of Strain Rate In Plastics, Ashok B. Choksi

Theses and Dissertations

As new materials are developed, it is essential to study their mechanical properties experimentally. It is easy to find properties like ultimate strength, yield strength, hardness, etc., using standard techniques. It is not possible to observe the tensile behavior of materials at high strain rates using standard equipment. Plastics are often subjected to tensile loads at various rates of loading, such as when they are used to absorb impact.

Study Of Tensile Stress Versus Strain Characteristics Of Vinyl Plastic At Various Temperatures As A Function Of Strain Rate, Jitendra T. Parikh

Theses and Dissertations

The purpose of this thesis was to study the tensile-stress versus strain characteristics of vinyl plastic at various temperatures as a function of strain rate.

A Similarity Model For Flow In A Turbulent Boundary Layer, Earl Clark Lemmon

Theses and Dissertations

One of the basic goals in engineering is to generate models which will provide a means for analytically predicting observed phenomenon. Such a model is often modified several times to obtain better results. The purpose of this study was to generate a model for an equilibrium turbulent boundary layer for steady flow over a flat plate and compare the results obtained by using the model with experimental data. Part of the objective was to also suggest ways in which the model could be modified to obtain better results.

Developing Turbulent Flow In An Annulus, Dwight H. Kelly

Theses and Dissertations

Turbulent flows are encountered in nearly every case where fluid motion is involved. Since turbulent flow through relatively short annular sections occurs frequently in practical applications, e.g., flow through heat exchangers, axial flow turbomachinery and jet aircraft engines, there is a need for detailed information on this subject.

The Enrichment Of Hydro-Carbon Fuel By Aluminum Powder In An Open-Hearth Furnace, Rick Sung-Tao Lee

Theses and Dissertations

The objective of this thesis was to study theoretically the enrichment of hydrocarbon fuels with aluminum powder for an open-hearth furnace.

Electric Arc Welding Of Gray Cast Iron Without Preheating, Ramon Prestwich

Theses and Dissertations

Cast irons are iron-carbon alloys with greater than 1.7% carbon. Although white, malleable and ductile cast irons are used extensively for casting work, this study is concerned with only the gray cast irons.

Automation In The Design Of Asynchronous Sequential Circuits, Richard T. Smith, James H. Tracey, W. L. Schoeffel, G. K. Maki

Electrical and Computer Engineering Faculty Research & Creative Works

Sequential switching circuits are commonly classified as being either synchronous or asynchronous. Clock pulses synchronize the operations of the synchronous circuit. The operation of an asynchronous circuit is usually assumed to be independent of such clocks. The operating speed of an asynchronous circuit is thus limited only by basic device speed. One disadvantage of asynchronous circuit design has been the complexity of the synthesis procedures for large circuits.

Ptimal Feedback Control Of The Radioactive Voltage Standard, David William Braudaway

Electrical and Computer Engineering ETDs

The quest for new and different techniques of establishing and maintaining the electrical values is continual Among the techniques desired are those for producing highly predictable sources of voltage. Described in this dissertation is a working device developed around one such technique, the research done to define the system and the synthesis of the automatic control which makes it practical. In this system, the reproducibility of the voltage output is derived from the predictability of the decay of a radioactive heat source.

Problems In Structural Diaphragm Bracing 1. Beams Continuously Braced By Diaphragms 2. I-Section Columns Braced By Girts And A Diaphragm, T. V. S. R. Apparao, S. J. Errera, Gordon P. Fisher

CCFSS Library (1939 - present)

Shear-resistant light-gage metal diaphragms can be very effective in increasing the load carrying capacity of beams continuously braced by diaphragms, or of columns braced by girts which in turn are braced by diaphragms, if proper connections are made between the individual elements. In this thesis, behavior of diaphragm-braced I-beams, channel beams, and Z-beams under uniform moments, and the behavior of axially loaded I-section columns braced by girts which in turn are braced by diaphragms are investigated.

Load-deflection relationships of diaphragm-braced beams are obtained taking into consideration the initial imperfections of the beams and using the equilibrium method. Critical moments of …

The Dynamic Behavior Of Steel Frame And Truss Buildings, Dixon Rea, Jack G. Bouwkamp, R. W. Clough

CCFSS Library (1939 - present)

This report describes experimental and analytical studies of the dynamic behavior of the East Building of the University of California's new Medical Center at San Francisco, California. It also describes experimental tests conducted on the East Building's mechanical service tower and on an adjacent elevator tower. Experimental tests on the East Building were conducted in the summers of 1964 and 1965. Vibrations were produced by eccentric-masstype vibration generators. Frequency responses, time responses, and mode shapes were observed. In the summer 1964 tests, the first mode east-west had 2% of critical damping and the first mode north-south had 1.8%; the values …

Structural Behavior Of Small-Scale Steel Models, William A. Litle, David C. Foster, Duke Oakes, Philip A. Falcone, Richard B. Reimer

CCFSS Library (1939 - present)

No abstract provided.

Transient Pulse Transmission Using Impedance Loaded Cyclindrical Antennas, David E. Merewether

Electrical and Computer Engineering ETDs

Two aspects of the problem of pulse transmission using impedance loaded cylindrical antennas have been considered. First, an approximate solution is obtained for the current distribution on a thin cylindrical antenna driven at an arbitrary point along its length. This solution may be applied to an antenna of any length, and its simplicity makes the current distribution rapidly computable. This solution is ideal for the prediction of the transient electromagnetic field radiated when an arbitrary voltage transient is impressed across the input terminals of a long, thin, cylindrical antenna loaded with lumped im­pedances. Second, an antenna synthesis procedure was evolved. …

Deformation And Energy Absorption Capacity Of Steel Structures In The Inelastic Range, Theodore V. Galambos

CCFSS Library (1939 - present)

This report summarizes the status of knowledge on the inelastic deformability of steel members and frames. It demonstrates that the inelastic response of planar beams, beamcolumns, connections and frames is well understood and can be adequately, though conservatively, predicted by theory provided the loading is static, proportional and monotonic, and adequate provisions are made to inhibit premature local and lateral-torsional instability. The report reviews the available theoretical work, and examines the experimental evidence. It shows that the inelastic rotation capacity, which defines also the "ductility factor" and the inelastic energy absorption capacity, is both predictable and large enough to meet …

A High Current Density Pulse-Mode Proton Source: Preliminary Study, Warren D. Smith

Electrical and Computer Engineering ETDs

A neutron source which produces high density pulses is useful, for example, in the simulation of an atomic blast or in neutron activation chemical analysis. Rather than forming pulses by deflecting the deuteron beam emitted from a continuous source of deuterons onto and off of a tritium target, it was decided to investigate the possibility of transient deuteron production. Proton sources were studied in place of deuteron sources because of the availability of hydrogen gas for experimentation. An experimental system was set up in which transient electrical discharges through hydrogen could take place. It was hoped that discharges could be …