Engineering Commons^™

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 …

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.

Effects Of Pressure On The Mechanical Properties Of Magnesium, Joseph George Hoeg

Masters Theses

"The data collected in an attempt to evaluate the pressure dependency of the mechanical properties of extruded AZ31B-F magnesium alloy are presented herein. This information was compiled from the results of compression tests run in hydraulic fluid environments pressurized to 50,000 psi, and tension tests run in the atmosphere. Specimen axial load and longitudinal strain were recorded and converted to effective stress and effective strain parameters for presentation. The term pressure is defined, in this report, as the negative average of the principal stresses or, essentially, the negative of the hydrostatic component of stress. The effective stress and strain, at …

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, …

Solid State Squib Simulator, Ernest Paul Lee

Masters Theses

"The simulators described in this paper allow checkout of the electrical control circuitry of pyrotechnic and related devices where the actual testing of the devices would be destructive. A simulator is described that is superior to the units now available for test purposes. Solid state components are used exclusively and hence it is very light weight and reliable. It is portable and requires no external power for indication of the control circuitry performance. The simulator presents a load that is adjustable between one and five ohms for a controlled length of time from one to one hundred milliseconds. Transients will …

Computer Simulation Of Radiation Damage In Fe₃Al, Roland Otto Jackson

Masters Theses

"A computer program, designed to simulate the ordered state of the B.C.C. alloy, Fe₃Al, was used to study the effects of irradiation on an order-disorder alloy. Twenty-six runs were made with this program representing a variety of initial conditions. In all cases, the final damaged state consisted of Frenkel defects, vacancy-interstitial pairs; and the distance separating these pairs was a sensitive function of the energy and direction imparted to the primary knock-on. Both the vacancy and the interstitial were found to be normal, stable defects, with the interstitial residing in a "split"-configuration oriented in the [110] direction. The threshold energies …

Behavior Of Reinforced Concrete Deep Slabs Subjected To A Uniform Load., Golden E. Lane Jr.

Civil Engineering ETDs

Within the last ten years a considerable amount of research has been conducted to determine the behavior of reinforced concrete deep

structures. The major portion of this recent research has been devoted to deep beams. The results have shown a marked difference in the behavior of deep beams as compared to beams of “normal” proportions. In

this context the word "deep" implies a small span-to-depth ratio. There is not a clear-cut distinction between a "normal-depth" and a deep struc­ture; however, span-to-depth ratios less than ten would suggest deep structures. The difference in behavior between deep beams and normal depth beams …

Analysis Of Semi-Conductor Ignition Systems With Emphasis On Design, Construction, And Operation Of The "Ideal" System, Frank P. Rundle

Masters Theses

No abstract provided by author.

Investigation By Neutron Diffraction Utilizing White Neutron Radiation, Arlen Ray Schade

Doctoral Dissertations

"The most probable reactor core neutron velocity was determined by analysis of data obtained from single crystals of copper and lithium fluoride. Derivation of the relationship between the maximum in experimental count rate and the most probable velocity, an error analysis of the method, and the computer routine are given for the method used to obtain the most probable velocity. The most probable velocity was used to index the maxwellian distributions from polycrystalline materials. Investigations were done with white neutron radiation of various silicon steel samples of different preferred orientation. A method is described by which the preferred orientation of …

The Effect Of Polymer Structure On Drag Reduction In Nonpolar Solvents, Gin Chain Liaw

Doctoral Dissertations

"The effects of polymer chain flexibility, molecular weight and entanglement capacity, and of polymer solution concentration on drag reduction in nonpolar solvents were studied in this investigation. Three samples of polydimethyl siloxane in toluene, five samples of polyethylene oxide in benzene, two samples of cis-polyisoprene in toluene, trans-polyisoprene in toluene, cis-polybutadiene in toluene, ethyl cellulose in toluene and a copolymer of epichlorohydrin and polyethylene oxide in toluene were studied. Molecular weights of all polymers were estimated from intrinsic viscosity, except for the molecular weight of the copolymer which was given by the manufacturer. Turbulent and laminar flow pressure drop data …

Distributed Parameter Rc Network Analysis, Robert C. Peirson

Doctoral Dissertations

"Methods of analyzing uniform and tapered distribute [sic] parameter RC networks are reviewed and correlated in this dissertation. Multilayer networks and simple three layer networks are considered. Analogies between two-wire transmission line theory and multilayer distributed network theory are developed, i.e., standing wave and traveling wave concepts. An accurate computer-aided steady state analysis procedure is presented which has a solution accuracy that can be determined prior to actual analysis computations. The impulsive response of the uniform RC network is investigated with the goal of measuring the network's parameters. Procedures to determine the parameters R and C of a uniform RC …

Analysis Of A Focus Log Electrode In A Non Homogeneous Medium, John Julian Zenor

Doctoral Dissertations

"The mathematical model presented for the focused logging system is applicable to any resistance logging tool of the electrode type. Horizontal or cylindrical resistance interfaces may be included in any combinations. The tool and its environment are compartmentalized, and the integral form of the condition for continuity of current is applied to each compartment. Acceleration methods are applied to the iterative solution of the resulting large-scale system of linear equations. Two specific models are presented, one for the study of the effects of invasion and the other for the study of the effects of bed thickness on the apparent resistivity …

Effect Of Micelles On Flotation Of Metal Ions, Uriel Michael Oko

Doctoral Dissertations

"A study of the anionic surfactant, sodium dodecyl sulfate (SDS), and the dependency of the adsorption of divalent metal counterions such as copper and zinc at the air-water interface on its concentration in the solution, was undertaken in order to better understand the process of ion flotation. The study is divided into two broad categories, the first of which consists of the evaluation of the extent of aggregation of the surfactant molecules into micelles, and the effect of the divalent metal counterion concentration on this aggregation and on the critical concentration at which micelles start forming (cmc). This was accomplished …

A Study Of The Anodic Oxidation Of Ethylene On Gold And Gold-Platinum Alloys, San-Cheng Lai

Doctoral Dissertations

"The distinctive features of electrochemical energy conversion is the direct conversion of the chemical energy of a reaction into electrical energy without going through the intermediary of heat, thereby avoiding the Carnot limitation. Since it is theoretically possible to obtain electrical energy to the extent of the free energy change of the chemical reaction, the overall thermal efficiencies expected are nearly 100 percent. However, the observed efficiencies of most electrochemical energy converters are considerably lower than this due to a slowness of one or more of the intermediate steps of the overall reaction. There has been a recent surge of …

A Numerical Simulation Of Pressure Distribution And Radius Of Drainage In Infinite Radial Aquifers - Constant Rate Case, Alton John Nute

Doctoral Dissertations

"The diffusivity equation for the transient flow of slightly-compressible liquids has been solved for infinite radial aquifers, subject to constant terminal rates, by employing a Romberg integration of the Van Everdingen - Hurst explicitly solution over the transformed integral limits for .01̲TD>500, the classical solutions presented by Carslaw and Jaeger, Mortada, Theis, and others are incorporated in the digital analysis to yield dimensionless pressures for 40 selected dimensionless radius (RD) ratios between 1 and 64 for dimensionless time values of .0005 to 1000.0. A new expression for dimensionless pressure-distribution, PD'(RD, TD), as a fraction of well bore pressure drop …

Optical Reflectance Spectra Of Chromium (Iii) In Mgo-Ss, Thomas Spencer Montgomery

Doctoral Dissertations

"The valence state and coordination site of the transition-metal ion, chromium, was investigated in a MgO host lattice. The chromium ion incorporated into poly-crystalline MgO by quenching from elevated temperatures allowed investigation of a single crystalline phase, MgO-solid solution (ss). The chromium ion was confirmed to occur in the trivalent state and to occupy octahedral cation sites in the MgO lattice by the use of optical reflectance spectroscopy. The effect of the concentration of the chromium ion on the crystal field splitting energy, 10 Dq, permitted analysis over a range of Dq/B values. In conjunction, MgO-ss lattice parameters examined as …

Multiport Synthesis With Multi-Layered Distributed Parameter Rc Networks, Walter Ronald Koenig

Doctoral Dissertations

"Synthesis and design techniques for multiport, multilayered, distributed parameter RC networks are investigated in this dissertation. The basic building block is a network section of uniform width consisting of alternate layers of resistive and dielectric materials on top of a perfectly conducting plane. The resulting network is composed of a cascade of these sections with all access terminals at one end of the cascaded network. The terminals at the other end are either open circuited or short circuited. A method is discussed for synthesizing a network from a prescribed network admittance matrix. An approximation technique is given for obtaining a …

Decomposition Of Cr(Oh)₃ To Form Active Cr₂C₃, Timothy A. Clancy

Doctoral Dissertations

"This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per …

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 …

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; …

A Method For The Calculation Of The Electric Microfield Distribution In A System Of Charged Hard Spheres, Ronald M. Flegal

Masters Theses

No abstract provided.

A Study Of A Differential Equation Found In Wave Propagation And Scattering Theory, Larry W. Thacker

Electrical and Computer Engineering ETDs

The study of a differential equation that is found in the study of the scattering of waves from an inhomogeneous media and in atomic collision theory is presented. Several integral formulations for obtaining approximations to the solution are discussed and studied. Means of determining the phase shift in electron scattering problems are presented, and two methods for obtaining the reflection and transmission coefficients are developed and discussed.

A Study Of The Operating Characteristics Of An Adiabatic Calorimeter, Carl L. Wheeler Jr.

Mechanical Engineering ETDs

1.1 General Problem

New technological developments in the areas of arc testing, hypersonic flow, rocket propulsion, and re-entry heat shield design require new thermophysical data on heat resistant materials. The present investigation is concerned with the development of a calorimeter which has the capabilities for obtaining specific and latent heat data on these materials in the temperature range of ambient to 1,000° C. The criteria for this development are

a. that operation be easy: the calorimeter should be operated by only one observer;

b. that data be rapidly determined: no more than two to eight hours should be required to …

Numerical Studies Of An Inverse Pinch Device, John Richard Freeman

Electrical and Computer Engineering ETDs

The inverse pinch configuration has been recognized as a possible means of producing stable, repeatable shock waves in a plasma for laboratory investigation. The simple geometry permits investigation of cases with or without an initial transverse magnetic field in an un-ionized or pre-ionized medium. Previous analytic work for this geometry has been restricted to a snowplow model, sometimes including coupling with the external circuitry. The solution presented here consists of a finite difference, Lagrangian coordinate system solution for a one-fluid hydromagnetic model. The hydromagnetic model chosen includes the effects of a variable degree of ionization, assuming a hydrogenic plasma. Complete …

The Overall Force-Deformation Relations Of Latticed Frames, Syamal C. Dasgupta

Civil Engineering ETDs

Most elastic bodies in the field of civil engineering are composed of discrete elements which are interconnected in some way. A distinct characteristic of such systems is the presence of jump discontinuity in the physical properties of the systems. Trusses, ribbed shells, multi­story frames, continuous and folded plates, built-in columns, etc. are a few examples of this kind. From the conventional methods of analysis of these systems, it can be realized that considerable effort is being expended to approximate the actual system by .means of a relatively simpler system. Most of the established methods of analysis of such systems involve …

Compensating Techniques For Reducing The Response Of Transistor Circiuts In A Transient Radiation Environment., Goebel Davis Jr.

Electrical and Computer Engineering ETDs

The effect of transient radiation on electronic components has become a vital concern of the military. It is mandatory that certain critical ground installations, aircraft, and missile systems for the military be both reliable and effective and if possible not be rendered temporarily or permanently inoperative due to exposure to a pulse of gamma radiation.

The Development And Use Of A Double Beam Photoelectric Polarimeter For The Study Of The Faraday Effect, John Norman Rowe

Masters Theses

No abstract provided.

A Study Of Frictional Drag Force Reduction On A Flat Plate By The Injection Of A Dilute Solution Of Guar Gum Into The Boundary Layer, Neil Henry Clay

Theses and Dissertations

The study of frictional drag force reduction has been the subject of much research for many years. One of the significant developments in the field of frictional drag force reduction has been the discovery of the effectiveness of dilute polymer solutions in reducing drag. By using dilute high-polymer solutions frictional drag forces in pipe flow have been reduced by as much as 70 per cent.

A Study Of Thermal Responses Of A Body Of Complex Geometry To A Moving Heat Source, J. Norman Smith

Theses and Dissertations

The effect of the fusion welding process upon the metals being welded is a matter of great interest and has been the subject of much investigation, both theoretical and experimental. The properties of metals are determined by the structure of their crystals (within limits for any given metal), and the crystalline structure is determined by heating and cooling rates. Thus the knowledge of temperatures, and heating and cooling rates, becomes the key to understanding these effects of heating. Since the greatest part of fusion welding is done using a gas torch or an electric arc, the necessary theoretical study is …

Model Study And Analysis Of The Flow Elements Of A Recirculation Mixing System, Albert Warren Berg

Theses and Dissertations

The term water clarifier as used in this text refers to a versatile water treatment unit which combines flocculation and coagulation, clarification and positive sludge removal in a single tank. Water clarifiers are very compact units which are being used in municipal and industrial water treatment for the removal of turbidity, algae, color, iron and silica; lime or lime-soda softening; magnesium precipitation; brine clarification; and waste water clarification with or without chemicals. Water clarifier units have found wide use in the sanitary field, providing high removals in the pre-treatment of sewage and in secondary sewage treatment through addition of coagulants.