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Some Factors Affecting The Results In Cyclic Triaxial Tests, Suresh Kumar Chaudhary

Masters Theses

"A major cause of damage to structures and earth embankments during earthquakes or any other such dynamic vibrating loading conditions has been the liquefaction of saturated sands. There have been several investigations to establish a convenient and relatively simple laboratory test procedure and to study the nature of field conditions leading to sand liquefaction. This investigation evaluates the effects of sample size, testing frequency, and the method of sample preparation on the number of cycles to cause initial liquefaction in pulsating triaxial tests using standardized equipment and test procedures. It has been found that sample size does affect test results …

Contractor Quality Control: A Method Of Construction Inspection, John Scott Treadwell

Masters Theses

"It has become apparent in recent years that the United States Government's construction contract supervision and administration procedures are causing an increase in contractor claims and disputes and that the system itself is becoming prohibitively expensive. To deal with some of these problems, the Department of Defense is attempting to implement a new approach to construction inspection--Contractor Quality control. Under the Contractor Quality Control System the majority of the standard contract inspection and testing responsibilities are placed on the contractor, and the Government relinquishes its traditional step-by-step inspection and testing procedures and withdraws to a position of contract surveillance. The …

Shop Level Maintenance Of Inertial Platforms Without A Surveyed Site, Max E. Bott

Masters Theses

"The initial installation of a rotary tilt table for an aircraft inertial navigation system test facility includes accurately aligning the rotary tilt table to local level and true north coordinates. The survey techniques presently employed are an encumbrance during installation and complicate remote deployment. The objective of this thesis is to determine if an inertial platform or platforms can practically be used to replace the role of the survey techniques in the rotary tilt table alignment. The construction, capability and operation of a rotary tilt table are reviewed. The tests necessary to test and calibrate an inertial platform are outlined, …

The Effect Of 15% Mno On The Phase Relations In The System Cao-Feo-Sio₂ At 1450ºc, Aquil Ahmad

Masters Theses

"A study was made of the phase relations at 1450ºC in the systems CaO-FeO-SiO₂ and CaO-FeO-SiO₂ -15% MnO, in equilibrium with metallic iron. The stability region of different phases was determined by microscopic examination and electron-beam microprobe analysis of the quenched specimens. The effect of 15% MnO on the liquid saturation boundary of the system CaO-(FeO+MnO)-SiO₂ was discussed in terms of the effect of MnO on slag making reactions in the Basic Oxygen Furnace steelmaking process"--Abstract, page ii.

The Influence Of Temperature, Carbon Content, And Preloading On Secondary Consolidation Of A Clay, Richard Kai-Ming So

Masters Theses

"The effect of temperature, organic carbon content, and preloading on secondary consolidation of Bryce clay has been studied. A straight line plot of void ratio versus logarithm of time was established in secondary consolidation for long term loading periods up to one month. Temperature changes within the range of 5ºC. to 45ºC. were studied in the secondary consolidation phase at different stress levels and different carbon contents of the soil. Secondary consolidation in a preloading cycle at a stress level of 2 tsf unloaded to 1 tsf and reloaded to 2 tsf was studied. The preloading tests were at temperatures …

Triangular Signal Stabilization Of Nonlinear Systems, Kamaleddin Yadavar Nikravesh

Masters Theses

"Many nonlinear systems display self-sustained oscillations which are often undesirable. The stabilizing effect of a high frequency input signal on an oscillating system with one nonlinearity is determined by the characteristics of the nonlinear element in the system, the linear portion of the system and the amplitude of the signal. This investigation has been concerned with the effect of a triangular wave stabilizing signal on these self oscillations. The equivalent gains for several common nonlinearities are derived. The pseudo describing function introduced by Oldenburger and Boyer for sinusoidal stabilization has been extended to the triangular wave case, and it is …

An Experimental Determination Of The Effect Of The Axisymmetric Turbulent Wake On The Pressure Distribution On A Sphere, Martin Gardner Bowin

Masters Theses

"A study of the effect of the turbulent wake of a water drop on the motion of a smaller droplet is essential in order to gain an understanding of the behavior associated with the collision coalescence phenomena. The use of spheres of macroscopic size proves to be a valuable method in observing these effects. This experimental investigation centers on (1) a check on the validity of the instrumented sphere as a device to measure normal static pressure, and (2) the study of the effect of the turbulent wake of the test model sphere upon the instrumented sphere. Measurements were made …

The Effect Of Cathodic Protection On The Stress Corrosion Characteristics Of 300m Low Alloy Steel, John Pechonick

Masters Theses

"The objective of this investigation was to determine if stress corrosion failure of 300M steel is accelerated by the application of cathodic protection. Testing was conducted on notch tensile specimens that were coated with vacuum cadmium, electroplated cadmium, and vacuum aluminum. All specimens were stressed and placed in an aqueous sodium chloride environment. The failure times for the specimens were monitored and graphs were drawn which characterized the stress corrosion resistance of 300M steel and the cathodic protection systems. Fractography techniques were used to study the failure surfaces to determine the type of failure mechanism. The results of this thesis …

The Effect Of A Knurled Heat Transfer Surface Upon Pool Nucleate Boiling Of Normal Pentane, Jerry James Carr

Doctoral Dissertations

"The effect of knurling a nucleate boiling heat transfer surface was studied. The knurling utilized produced regular, four-sided, adjacent pyramids with an apex angle of 90 degrees. Four knurling densities were used ranging from 416 to 2591 pyramids per square inch. The transfer surface was gold-plated copper and the heaters used were electrically heated, ten-inch long, horizontal cylinders of one-inch diameter. The liquid boiled was normal pentane at its saturation temperature and a pressure of 760 millimeters mercury.

For some of the knurled surfaces the temperature difference required to produce a given heat flux was found to be less than …

An Investigation Of Subsequent Yield Phenomena, Joseph George Hoeg

Doctoral Dissertations

"A method utilizing high pressure fluid environments is described whereby a three-dimensional subsequent yield surface was determined for 304 stainless steel. Cylindrical parent specimens of this material were prestrained in axial compression under fluid pressure and then small sub-specimens were sectioned from these parent specimens. Finite element techniques were used to optimize the parent specimen size so that a zone of uniform axial stress would result during the prestraining. Longitudinal strains in this zone were monitored during the prestraining and the sub-specimens were cut from this region in a manner that did not allow the machining to appreciably affect the …

On-Line Economic Optimization Of A Chemical Reactor, Jesse Daniel Bennett

Doctoral Dissertations

"An economic optimizing control system for a continuous flow stirred tank chemical reactor is designed, simulated, and installed on a pilot scale reactor. The control scheme utilizes a reaction and reactor model to predict on-line the economic optimum of a reactant concentration. In this manner the control system manipulates the reactant flow rate to maintain the optimum concentration during changes in reaction-reactor parameters with time. Typical parameter changes include the decay of reaction catalyst activity. The optimizing controller will function in conjunction with various operating policies including control to maintain a specified production rate"--Abstract, page ii.

Response Surface Study Of A Characteristic Chemical Plant, John Thomas Mason Iii

Doctoral Dissertations

"Study of the return on investment response surface of a characteristic chemical plant indicates unimodality in the valid region, but the optimum design condition with this response surface is strongly affected by the correlation used for the investment. The method used for the design of this type of chemical plant incorporates the use of a simulation routine for preliminary estimates"--Abstract, page ii.

The Genesis Of Cellular Precipitation In Copper Rich Copper-Indium Alloys, Raymond Albert Fournelle

Doctoral Dissertations

"The morphology of cellular precipitation in a Cu-9.5at.%In alloy has been investigated by light and electron microscopy and x-ray and electron diffraction. Both cellular and general precipitation were observed to occur simultaneously in quenched and aged alloys while only cellular precipitation was observed to occur in isothermally aged alloys. Because of the presence of wide, vacancy depleted precipitate free zones in the vicinity of grain boundaries, general precipitation was observed to have no effect on the early development of cellular precipitation. Hence, the early development of cellular precipitation was found to be identical for both types of heat treatment. By …

Thermal Lattice Expansion Of Various Types Of Solids, Jayantkumar Shantilal Shah

Doctoral Dissertations

"Thermal lattice expansion studies of various types of solids were carried out in this investigation and were corelated to their crystallographic and various other properties. The advantages and limitations of various methods of studying thermal expansion are discussed in detail. A new design for a versatile low temperature camera to study expansion by an X-ray method is proposed. The thermal lattice expansion of silicon was negative below 119ºK. This behavior is discussed in terms of crystal structure and interatomic bonding. Diamond exhibits no anomalous thermal expansion. Lattice parameter data for many metals at low temperatures are reported for the first …

Surface Reactions Of Boron With Clean Tungsten Substrates, Thomas A. Flaim

Doctoral Dissertations

"A model developed to predict adsorbate-induced work-function changes for thermionic emitters is shown here to apply to a more general class of electron emission phenomena and a much broader range of adsorbates. This model predicts that chemically, vapor-deposited boron will increase the work function of a clean tungsten substrate at coverages between 0 and 1 monolayer. This is the first time that a single model has been shown to predict both positive and negative work function changes for different adsorbates. The reactions of chemically, vapor-deposited (CVD) boron with clean tungsten substrates were studied using field emission microscopy (FEM) and low …

Detection Of Delay Time And Filtering Using Sequency Domain Technique, Earl F. Richards

Doctoral Dissertations

"A procedure is presented by which it is possible to detect a known signal of unknown delay in a noisy medium contaminated by noise. From the results the characteristics of a sequency digital filter which would be required to remove the noise contamination is indicated. The Walsh functions are discussed and the sequency domain, which is analogous to the continuous frequency domain, is used in the spectral analysis of signals. The binary nature of the Walsh functions and their ease of generation makes processing of signals easier than the Fourier analysis approach. The applications of fast forward and inverse Walsh …

An Investigation Of The Radiation Polymerization Of Methyl Methacrylate-Kaolin Clay Composites, James Jackson Beeson

Doctoral Dissertations

"A kinetic and characterization study has been made on the effects of gamma-rays (Co⁶⁰) on the polymerization of a 50-50 weight mixture methyl methacrylate (MMA) kaolin clay system. The effect of dose rate (7.35 - 24.9 rads per second), temperature (25 to 75ºC) and total dose on the percentage conversion of monomer to polymer was studied. The rate of formation of polymer at 25ºC in the composite system was found to be faster when compared to a bulk MMA system at the same experimental conditions. This acceleration showed that the clay had a catalytic effect on the formation of polymer. …

Use Of The Turbulence Kinetic Energy Equation In Analyzing Turbulent Near Wakes, James Edward Auiler

Doctoral Dissertations

"A general method is presented for analyzing turbulent flow fields in the near wake regions of two-dimensional and axisymmetric bodies. The governing partial differential equations of continuity, momentum and turbulence kinetic energy are expressed in elliptic form in terms of the dependent variables stream function, vorticity and turbulence kinetic energy. An iterative finite-difference technique is used to solve the governing equations simultaneously. Numerical solutions are obtained for the following physical problems: 1. Laminar near wake: Only stream function and vorticity are considered for laminar flow. Solutions are compared with available analytical results for uniform flow over a sphere. 2. Turbulent …

An Age Hardening Study Of Magnesium-Thorium-Manganese Alloys, Kuldip Singh Chopra

Doctoral Dissertations

"The age hardening processes in Mg-3.5 wt.% Th-1.0 wt.% Mn and Mg-1.0 wt.% Th-1.0 wt.% Mn alloys have been studied by light and electron microscopy, and by electron and X-ray diffraction. At aging temperatures of 300ºC and below, G.P. zone formation rapidly hardens these alloys followed by the precipitation of disc shaped plates during averaging. During aging above 300ºC, no G.P. zones form and the disc shaped precipitate grows to very large sizes. The combined results of X-ray and electron diffraction indicate that the disc shaped precipitate has a Mg₃Cd (DO₁₉) type structure. The basal plane of the Mg₃Th discs …

A Measurement Of Complex Viscosity With Large Amplitudes, Kuo-Shein Shen

Doctoral Dissertations

"In order to study the viscoelastic properties of polymer solutions and greases, a dynamic apparatus was built for making measurements of complex viscosity. Characteristic impedance was measured by a force transducer, an accelerometer and a phase meter. Large amplitudes to 0.5 inch can be obtained with this apparatus. The largest amplitude used was 1.27 x10⁻¹ cm. The frequency range was 30 Hz - 1500Hz. The lowest dynamic viscosity to be measured was 0.5 poise. In order to determine the capabilities of the instrument, complex viscosities of polymer solutions and greases were measured. The polymer solutions studied were polyisobutylene (PIB) L-80, …

Internal Friction Of Ion Exchanged Li₂O•Al₂O₃•2sio₂ Glasses, A. Ismail A. Abdel-Latif

Doctoral Dissertations

"Li₂O•Al₂O₂•2SiO₂ glass fibers were ion-exchanged from 1 to 300 minutes in a sodium nitrate bath at 366ºC. The internal friction was measured along with the lithium and sodium concentration profiles. As sodium progressively replaced lithium, the alkali internal friction peak became smaller while a new peak (mixed alkali peak) appeared and increased in magnitude. These changes in the internal friction are similar to those that occur upon the addition of a second alkali to glasses prepared by conventional melting. The magnitude of both internal friction peaks in ion exchanged glasses was dependent on the overall glass composition. The magnitude of …

Statistical Study Of Rock Drilling By Hypervelocity Jets From Explosive Shaped Charges, John William Brown

Doctoral Dissertations

"The drilling effect in rock of hypervelocity jets from explosive shaped charges was investigated experimentally to supplement a rapid excavation concept. The effects of the design factors of the charge and the mechanical properties of eight rock types were studied. Experiments were both designed and analyzed upon statistical principles. A full factorial experimental design was used for each of seven rock types. An analysis of variance and the k-ratio least significant-difference test were applied to the results.

The optimum design of shaped charges for drilling was found to be independent of rock type and rock properties. For composition C-4 charges …

Finite Difference Solutions Of Axisymmetric Infiltration Through Partially Saturated Porous Media, Chi-Yuan Wei, Roland W. Jeppson

Reports

Solutions are obtained to the problem of steady-state partially saturated infiltration of moisture applied over a horizontal source circle which moved through homogeneous soils toward a water table. A commonly accepted relationship between relative permeability and capillary pressure has been utilized in conjunction wit Darcy’s law to formulate the mathematical model. The solutions have utilized an inverse formulation and have been obtained by finite difference. The inverse formulation considers the magnitudes of the cylindrical coordinates r and z as the dependent variables and the potential function and the Stokes’ stream function as the independent variables (i.e the problem is solved …

The Behavior Of Pvc Pipe Under The Action Of Water Hammer Pressure Waves, Gary Z. Watters

Reports

Introduction: Hydraulic transients, commonly referred to as water hammer, occur in a hydraulic system whenver the velocity of flow in any one of the pipes in the system is caused to change. The magnitude of the pressure waves generated by a given change in velocity depends on the geometry of the pipe system, the magnitude of the velocity change and the elastic wave velocity in the system componenets. In turn, the elastic wave velocity depends on the modulus of elasticity of the fluid and the pipe material, the size and thickness of the pipe, the method by which the pipe …

A Computer Model Of The Quantity And Chemical Quality Of Return Flow, Jimmie L. Thomas, J. Paul Riley, Eugene K. Israelsen

Reports

A hybrid computer program is developed to predict the water and salt outflow from a river basin in which irrigation is the major water user. A chemical model which predicts the quality of water percolated through a soil profile is combined with a general hydrologic model into form the system simulation model. The chemical model considers the reactions that occur in the soil, including the exchange of calcium, magnesium, and sodium cations on the soil complex, and the dissolution and precipitation of gypsum and lime. The chemical composition of the outflow is a function of these chemical processes within the …

Inverse Solutions To Three-Dimensional Free Surface Potential Flows, Roland W. Jeppson

Reports

Methods are developed and defined for obtaining numerical solutions to three-dimensional, free surface, invisvid, incompressible fluid flows and three-dimensional free surface Darcian flow in porous media. Since those boundaries consisting of free surface are unknown a priori, a solution to the space boundary value problem resulting from a formulation in the physical space is very difficult, if not impossible, to obtain. Consequently, the methods described herein are based on a formulation in a space defined by a potential function and two mutually orthogonal stream surfaces whose intersections define the streamlines of the flow. In this space the positions of free …

The Effect Of Carbon On Algal Growth--Its Relationship To Eutrophication, Joel C. Goldman, Donald B. Porcella, Joe E. Middlebrooks, Daniel F. Toerien

Reports

Introduction: Natural and cultural eutrophication (enrichment with nutrients) frequnetly results in excessive algal growths thereby reducing the beneficial uses of surface waters (Hasler, 1947; Thomas, 1955, Edmondson et al., 1956, Oswald and Golueke, 1966, Skulberg, 1967, Mackenthun et al., 1968, Goldman and Armstrong, 1969, McGauhey et al., 1968,1969, 1970a, 1970b). Recent reviews emphsize that the prevention of further reduction in the quality of water resources requires the implementation of effective control measures (Goldman, 1965, Steward and Rohlich, 1967, Middlebrooks et al., 1969, Rohlich, 1969). Effective control of cultural eutrophication must involve the manipulation of those factors which affect algal growth, …

Development Of A Procedure For Determining Spacial And Time Variations Of Precipitation In Venezuela, Luis E. Ramirez

Reports

An analysis of the influence of the length of the record in the reliability of mean values of precipitation was made for the Caracus-Cagigal Station in Venezuela. Ten series of values were obtained for 10, 15, 20, 25, 30, and 35-year periods, extracted for sliding intervals for the overall record of 75 years. The reliability of mean values computer from Figure 3 was quite low for 10, 15, and 20- year periods. The long term record means had higher reliability, increasing with the number of years in the records, but the differences are not important in terms of accuracy. Precipitation …

Detergent And Non-Detergent Phosphorus In Sewage, Donald B. Porcella, E. J. Middlebrooks

Reports

Introduction: Quantitative data on nutrient levels in sewage from homes which are using heavy-duty detergents and which have been restrcited from using such detergents is necessary before rational decisions on the removal of phosphorus from detergetn can be made. Furthermore, the effect of various standard sewage treatment schemes on phosphorus levels should be evaluated to determine the relative cost of such treatment. Then the cost (to society, the environment, and to the taxpayer) of phosphorus removal from detergent and/or from sewage effluents can be estimated and such data utilized to make the appropriate policy decisions. The report herein presented is …

Water Resources Planning And Social Goals: Conceptualization Toward A New Methodology, D. Peterson, H. Caulfield, R. D'Arge, D. Gordon, M Marts, T. Roefs, R. Roelofs

Reports

A modeling concept relating water resource use to