Engineering Commons^™

Bit Penetration Into Rock - A Finite Element Study, Jaw-Kuang Wang

Doctoral Dissertations

"A finite element approach has been developed to simulate bit penetration from bit-rock interaction to chip formation. A mathematical rock failure model, based on a review of the existing literature on rock tests, has been proposed to represent post-failure rock behavior and applied in the penetration simulations. The finite element program has been developed for two dimensional plane strain problems with non-linear material properties, geometrical nonlinearities and fracture. An anisotropic element as well as variable stiffness and stress release methods have been used. An iteration method, using an incremental approach, has been applied for continuous penetration and modifications of material …

Simulation Of Nonisothermal Absorber-Reactors For Multicomponent Systems, Robert E. Schwab

Doctoral Dissertations

"There are various models available for calculations involving one transferring component with chemical reaction for isothermal conditions using linear equilibrium data. However, the differential equations for multicomponent mass and energy transfer with chemical reaction have not been developed or implemented. This work demonstrates the development of a reliable model describing multicomponent mass and energy transfer in a continuous two-phase absorber-reactor for Non isothermal conditions and demonstrates the feasibility of solving the differential equations numerically. The numerical solution, using nonlinear equilibrium data, is used to obtain the absorber-reactor column specifications"-- Abstract, p. 2

Optimizing Underground, Trackless Loading And Hauling Systems, Richard Lee Bullock

Doctoral Dissertations

"Determining the optimum system and equipment to be utilized in today's underground trackless haulage mine is a complex problem which was dealt with in this research by systems simulation. The computer program developed by the Caterpillar Tractor Company served as the starting point for simulating the equipment's capabilities to move material over a course in a prescribed time. Extensive time studies of the unsimulated events lead to structuring this program in the deterministic mode since it was felt to be more acceptable to the operating management which would eventually use the technique. Every phase of the simulation was successfully validated …

Corrosion And Electrochemical Behavior Of Indium And Indium-Bismuth Alloys In Hydrochloric Acid, Yar Ming Wang

Doctoral Dissertations

"The corrosion of In-Bi alloys was studied using X-ray, scanning electron microscopy, atomic absorption spectroscopy, and cyclic voltammetry techniques.

Calculated activation energy values indicated that the corrosion of In-Bi alloys was activation controlled. The effect of amine mixtures on the corrosion of In and In₂Bi (ß₁ phase) was studied. Morphological studies revealed that the porosity of the resulting physical surface structure was influential in determining the corrosion rate. In deaerated 3N HCl solutions, the selective dissolution of indium was the predominant mechanism in the corrosion of In-Bi alloys. The corrosion was always accompanied by a phase change …

Innovative Industrial Arts Programs At The Junior High/Middle School And The Continuation Of Those Programs At The Senior High School Level In Iowa, James L. Thiesse

Dissertations and Theses @ UNI

The purpose of this study was to determine the percentage of junior high/middle schools in the State of Iowa using selected. newly developed industrial arts curriculums and to determine if the senior high schools serviced by them were continuing to expand upon that base of knowledge.

Objectives of the Study.

1. To determine the percentage of Iowa junior high/ middle schools using one or more of the selected newly developed industrial arts curriculums.

2. To determine the percentage of senior high schools in Iowa which were using or building upon one of the selected industrial arts curriculums.

3. To inquire …

Split-Film Anemometry In A Drag-Reducing Solution, Jack Chosnek

Doctoral Dissertations

"Turbulence measurements were made in the tube flow of mineral oil and a 0.2% solution of polyisobutylene in the same oil. Velocity profiles, axial and radial turbulence intensities, and axial and radial energy spectra were obtained in both fluids using a split-film anemometer probe. In addition, velocity profiles and axial turbulence intensities were obtained in oil using a 0.001-in. cylinder probe, a cone probe and a parabolic-wedge probe. The measurements were made in a one-inch tube at a constant fluid temperature of 30.0°C, in the Reynolds-number range of 4,800 to 50,000.

Four factors influenced the results in a greater manner …

Characterization Of Heat-Treated Nickel And Gold Films On Silicon Single Crystals, Ki Hyun Yoon

Doctoral Dissertations

"An experimental electron impact ionization source was used to determine the presence of various neutral atoms and molecules on metallized and bare surfaces of silicon wafers. The metallization consisted of thin films of nicke l and gold separately and in combination. The major surface contaminates on all samples were found to be F, Na, Cl, K, CO, and CO₂. The surface concentration of these species was found to be sensitive to the sample temperature up to 550 °C, the maximum temperature used in this study.

In the course of the mass spectrometric study, it was found that crystallites …

Effect Of Photoneutrons On Transients Of Beryllium Reflected Reactors, Safdar Ahmad Ali

Doctoral Dissertations

"An analytical model is developed to account for the photoneutron sources present in a beryllium reflector. The time-dependent, two- dimensional and three energy-group diffusion equations are written with an additional photoneutron source term. Then an approximate flux composed of two spatial shapes chosen beforehand, each having an unknown time coefficient, is inserted into time-dependent multigroup equations and the weighted residual criterion is applied. This yielded multimode kinetics equations with generalized definitions for conventional matrix parameters: generation time, reactivity, delayed neutron and delayed photoneutron fraction matrices.

Two transients are analyzed for the University of Missouri Research Reactor: simulation of rod drop …

Application Of Laser Holographic Interferometry To The Analysis Of Ground Movement Above Underground Openings, Duk-Won Park

Doctoral Dissertations

"A laser holographic interferometric technique has been recently developed and applied to research in several engineering fields. The technique has many possible applications in earth science and engineering. In this study it was shown that laser holographic ii interferometry can be used to study surface ground movements resulting from subsurface cavity collapse.

One of the most important advantages of the holographic interferometric technique is a rapid three-dimensional displacement measurement of a surface without contact or emplacement of instruments. The surface does not have to be flat or smooth allowing deflection contours to be generated on a granular surface. applied in …

Use Of Adaptive Linear Equalization And Maximum-Likelihood Sequence Estimation In Conjunction With Filtering To Improve Qpsk Communication In Intersymbol And Interchannel Interference Channels, Srinivasa H. R. Raghavan

Doctoral Dissertations

"At high data rates, bandwidth is more constraining than transmitting power. Twice the data can be transmitted in a given bandwidth by using quadrature phase-shift keyed (QPSK) modulation schemes as opposed to biphase phase-shift keyed (PSK) systems, with a corresponding factor of two increase in power required for identical bit-error-rate performance. At high data rates intersymbol interference due to media dispersion degrades receiver performance . Other degradation results from interchannel interference, co-channel interference and noise may also be present in typical situations.

Equalization is a technique by which the receiver performance in the presence of intersyrnbol interference can be improved. …

Application Of Voltammetry To Copper Electrodeposition, Louis Francis Toth Jr.

Doctoral Dissertations

"A study was undertaken to determine the feasibility of using voltammetry and scanning electron microscopy techniques to characterize copper deposition from an acid-sulfate electrolyte. The main process variables investigated were temperature and addition agents (chloride ion, glue, separan or thiourea) at different concentrations, over a range of current densities. Cathodes employed were either polycrystalline titanium or copper. Some long-time copper deposits were also made using Ti cathodes and the orientations of these deposits were determined by x-ray diffraction.

Observations of copper crystals produced during voltammetry scans, on a Ti cathode, indicated that a characteristic morphology was associated with each type …

Design, Fabrication, And Application Of Uniformly Distributed Rc Networks For Use In Electronic Circuits, Michael Flynn Kavanaugh

Doctoral Dissertations

"In the design of electronic circuits, both linear and non-linear, one of the goals is the reduction of the number of elements needed to complete the design. By using distributed RC networks a reduction in the number of elements by at least 50% is usually possible. This dissertation discusses several distributed RC networks, develops detailed design procedures for each, and applies them in the design of electronic circuits.

The indefinite admittance matrix (IAM) for the DRURC (double-resistive uniformly distributed RC network) and the URC (single-resistive uniformly distributed RC network) , which have been previously derived, are used as the starting …

Development Of Helicopter Flight Path Models Utilizing Modern Control Techniques, Alfred Fermelia

Doctoral Dissertations

"The nonlinear set of equations which represents helicopter motion are linearized about a prescribed nominal state. Once the linearized system is obtained it is validated by comparing the output of the nonlinear system to that of its linearized counterpart. Having obtained a linear model, linear system theory may then be applied in order to investigate the stability and control characteristics of the aircraft.

General techniques for simulating helicopter pilot response for inclusion in a flight path simulation program have been devised. To provide the desired flight goal, a nominal flight trajectory is obtained from an existing nonlinear model. With this …

Excitation Of Source Electromagnetic Waves At Microwave Frequencies Using Optical Techniques, M. Davarpanah

Doctoral Dissertations

"The coupling efficiencies for the excitation of surface electromagnetic waves (SEW} for both the prism and the grating techniques have been studied experimentally in the microwave frequency range. The grating experiments included studies of the SEW coupling efficiencies as functions of the frequency, the angle of incidence, the grating constant, the number of grating bars, and the position of the grating bar at which the maximum radiation field of the antenna was aimed. For the prism coupling technique, the coupling efficiency was studied as functions of the angle of incidence, the aiming point of the transmitting antenna on the prism …

Influence Of Initial Turbulence Intensity On The Heat And Moisture Transfer Through A Recirculated Air Curtain, Nguyen Quang Van

Doctoral Dissertations

"An air curtain is a directed jet of air separating a controlled space from an environment of different temperature and humidity. This investigation describes the development and verification of an eddy viscosity model which accounts for the influence of the initial turbulence intensity on the transfer of heat and moisture across a recirculated air curtain. The control of the turbulence intensity at the nozzle exit of an air curtain permits control of heat and moisture transfer and therefore the energy required to operate the air curtain.

Both theoretical and experimental studies were made of the recirculated air curtain. An explicit …

Design And Analysis Of An Instrument System For Rheological Testing Of Whole Blood Samples, Robert Rimvydas Sinusas

Dissertations

The dissertation covers the conceptual design of a rheometer for testing whole blood samples through to the clotting state. While the design aims at increased measurement accuracy, the design employs well known technologies and available components.

The main reason for preoccupation with blood testing is that recent investigations have indicated that physiological disorders can be correlated with rheological properties of blood. The pursuit of an improved means of correlation is initiated with a survey of the rheological properties of blood. The relevance of these blood properties is then discussed. From this discussion a broader blood model is developed as a …

Problem Oriented Teaching, Concept And Implementation, Beat Victor

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Reconstruction Work Upon Solima Pier, K Alibhai

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Committee For Relations With Industry - Its Role In The Training Of Engineers, A Shayo

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Industrial Projects Recommended By The Faculty Of Engineering Udsm, W Kreuser

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Frontal Instruction Or Group Work, Hans Wagner

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Books To Make Electronics Easy, P Mynott

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

The Fate Of The Developing Economies, F Mtalo

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

New Directions In Engineering Communications, H Mckague

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

The Development Of The Faculty Of Engineering, Udsm, W Kreuser

Tanzania Journal of Engineering and Technology (TJET)

Although gome of the buildings have not yet been completed, the Faculty has already moved into the new premises. The training workshops where all students spend nearly 5$ of their time during the first year of the undergraduate course are in full owing 'Ince 1973, the first laboratorleg will be ready for operation early 1975. The admi'ßion of students to the four years undergraduate eourøe and the distribution to the departments are represented on the table below.

Technology As General Subject In The Tanzanian Education, A Kanyilili

Tanzania Journal of Engineering and Technology (TJET)

There is no Coubt in Tango-nia tc-'d?.y that wc have accepted as T22tte-r• of policy thc need to el.1ÜhT.size Technology in our (Sce Ilycrcre: -Education for Self—Reliance, education system. Mn,rch 1974; Qanu Directive on Snall Scale Industries, M T.rch 1973 and Resolution 29 of the 16th Party Conference, October 1973) • In spite of all. thcsc ?ronounecnents, howcver, it Is very saa to note that there • very stroma doubt as to whether our education rnd nonpower planners, ond the policy nakers themselves are fully awn.rc of thc corn-plexities orecml— zation required to run a vinyl c, successful TechnolchUca11y based …

Dissemination Of Appropriate Technologies, H Dickinson

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Practical Training Of Students At The Faculty Of Engineering, Udsm, G Roesch

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Construction Of Pile Foundation For Hall Seven, Udsm, K Swai

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

Plough Parts Production At Ubungo Farm Implements, F Kavishe

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions