Engineering Commons^™

Initial Surface Reactions And Nucleation Kinetics Of Boron On Atomically Clean Molybdenum Substrates, Richard Eugene Moore

Doctoral Dissertations

"A study of the chemical vapor deposition (CVD) of boron from boron triiodide (BI₃) on molybdenum has been done with field emission microscopy (FEM) and low energy electron diffraction (LEED).

A correlation of the efficiency by which BI₃ is effectively dissociated to form adsorbed boron, and the temperature of the substrate has been shown through work function measurements on the boron covered molybdenum field emitter surfaces. The boron-induced work function change of molybdenum has been shown to be in agreement with a theoretical model which predicts positive, as well as negative work functions for adsorbate-substrate systems. It …

Implementation Of Recursive Algorithms For Delay-Time Estimation Using The Fast Walsh Transform, Donald Robert Nelson

Doctoral Dissertations

"Use of the fast Walsh transform to resolve noisy signals into Walsh function series to digitally implement maximum-likelihood parameter estimators for real-time use is investigated. Realization of estimators which seek a null in the derivative of the log-likelihood function, instead of direct maximization, results in feedback algorithms which yield considerable savings in computation time and storage. Performance of these feedback delay-estimation algorithms is characterized in terms of mean-squared error (MSE) and response to a delay step by Monte Carlo simulation. The effect of changing the number of points in the transform on the MSE is also investigated. Hard limiting of …

Film Boiling Of Benzene, Freon 113, Freon 11, And Normal Pentane From Horizontal Surfaces At Atmospheric Pressure, Richard Stanley Kistler

Doctoral Dissertations

"A film boiling study was conducted with five different area flat plates at atmospheric pressure for benzene, Freon 113, Freon 11, and n-pentane. The heat transfer surface was horizontal for all tests.

The data were compared to the correlations commonly used for heat transfer. The common correlations were found to be in error for small surface sizes, but adequate for all fluids except benzene for the largest surface, a semi-empirical equation which correlates the available data as a function of surface diameter was derived and discussed"--Abstract, page iii.

Measurement Of Molecular Diffusivities Of Liquid Alkane Systems, James W. Moore

Doctoral Dissertations

"An unsteady-state porous frit method of diffusion coefficient measurement, recently developed in this laboratory, was improved and expanded upon. The experimental technique has been refined and documented. The unsteady-state diffusion of an initially 0.5 N NaCl solution into pure water (effective diffusivity -1.480 x 10^-5 cm²/sec) was employed as the calibration standard. An overall calibration precision of ±4% was obtained. Diffusion times of two hours or less were used for the non-aqueous diffusivity measurements. The validity of this measurement technique was confirmed by the agreement of the measured self-diffusion coefficient of n-heptane (25⁰C) with literature values.

A …

An Application Of Residual Relaxation To Mathematical Simulation Of Petroleum Reservoirs, Grufron Achmad

Doctoral Dissertations

"Stability and convergence have long been primary concerns in the application of numerical techniques to the simulation of petroleum reservoir performance. An iterative method based on sequentially reducing the residual to zero at each grid point has been developed. It has been shown analytically that this residual relaxation method is stable, convergent, and consistent.

A three-phase areal model was developed to simulate a hypothetical homogeneous petroleum reservoir, and various computational methods were tested with this model. The residual relaxation method developed in this study (RELAX) was found to converge as rapidly as SIP, and much faster than either LSOR or …

Investigation Of Roof Shales In Illinois Coal Mines, Peter J. Conroy

Doctoral Dissertations

"This thesis describes an investigation of the relationships among the composition, physical properties and the performance of roof shales in Illinois coal mines. The study included cataloging the physical and mineralogical properties of typical roof shales, determining the interrelationships of the properties and defining the factors in the rock which effect deterioration. From the results, a classification system has been developed which may provide a means for evaluating coal mine roof stability.

A coring apparatus was developed for obtaining in situ samples from mine roofs. Five coal mines with varying geologic and roof conditions were sampled. Precautions were taken to …

Parameter Identification Applied To Linear Quadratic Differential Games, John D. Corrigan

Doctoral Dissertations

"A two player zero-sum linear quadratic differential game is investigated for the case in which one of the players has incomplete a priori knowledge of the parameters of his opponent's dynamic system. This incomplete system parameter information game is shown to be playable since the ignorant player can make limiting estimates of the unknown parameters from the relative controllability condition for the game. Performance from the ignorant player's point of view is suboptimal.

It is also shown that parameter identification techniques can be applied by the ignorant player in order to directly identify the smart player's closed-loop parameters in the …

Linear Stability Of Non-Parallel Flow In The Entrance Region Of Ducts, Francis Chung-Ti Shen

Doctoral Dissertations

"An investigation is made of the linear stability of the developing flow of an incompressible fluid in the entrance region of annular ducts, circular tubes, and parallel-plate channels. Small axisymmetric disturbances for annular duct and tube flows and small two-dimensional disturbances for channel flow are considered in the analysis. In formulating the stability problems, account is taken of the transverse velocity component of the mainflow. This results in the modified Orr-Sommerfeld equations, one for annular duct and tube flows and the other for channel flow. The mainflow velocity fields utilized in the stability analysis are those from the solutions of …

Rock Fragmentation By Subsurface Thermal Inclusions - A Finite Element Study, Mahendrakumar Ramkrishna Patel

Doctoral Dissertations

"Although rock tunneling machines are being used extensively with performance and cost advantages over traditional drill and blast methods, their usefulness for hard rock excavation is far from being practical due mainly to the inability of present day mechanical cutters to penetrate these rocks economically. Among various novel techniques that are being investigated, internal heating methods seem to be the most promising. This investigation is concerned with a feasibility study of thermal rock fragmentation using heat to create in-depth thermal inclusions.

The three-dimensional problem of in situ rock fragmentation involves parallel rows of equidistant holes drilled to a constant depth. …

A Study Of The Dynamic Loading Of Hydrodynamically Lubricated Journal Bearings, Nader Khorzad

Doctoral Dissertations

"The analytical and experimental investigation presented here examined the response of a full journal bearing to a unidirectional dynamic load. Frequency response of the bearing at different eccentricity ratios was investigated. It was concluded that the response of the bearing varies with eccentricity. The experimental data obtained was compared to an analytical model which considered inertial, damping, and elastic characteristics of the lubricant film. An investigation of film pressure revealed that the pressure due to journal center acceleration is smaller than the hydrodynamic and squeeze-film pressures"--Abstract, page 1.

Numerical Simulation Of Heat, Mass, And Momentum Transfer In An Atmospheric Boundary Layer, Darrell W. Pepper

Doctoral Dissertations

"Considerable interest has developed in recent years to understand transport phenomena in thermally stratified boundary layers. More complete knowledge in this field is needed to improve the prediction of the diffusion of air pollutants in the lower atmosphere as well as in forecasting air-water circulation for weather conditions.

The atmospheric boundary layer is modeled using the equations of continuity, momentum, energy, and concentration. Closure of this set of partial differential equations is hindered by the turbulence terms. Using turbulence kinetic energy, the system of equations is closed by internally determining the exchange coefficients of heat, mass, and momentum along with …

The Effects Of High Pressure And Temperature Environments On The Properties Of 6061-T651 Aluminum, Patrick George Davidson

Doctoral Dissertations

"During this experimental testing program the effects of the simultaneous application of high pressure and temperature environments on the mechanical properties of 6061-T651 aluminum were analyzed. From the data obtained at the yield and ultimate points a yield and ultimate model was developed based upon the parameters effective stress, effective strain, and the hydrostatic component of stress. This model was obtained solely from the data acquired from uniaxial tensile specimen tested at various pressures and temperatures. Two other loading paths--biaxial tension and torsion--were then used to verify the accuracy of the model. From the testing program, data were also obtained …

Dynamic Instability And Ultimate Capacity Of Inelastic Systems Parametrically Excited By Earthquakes, Wu-Hsiung Tseng

Doctoral Dissertations

"A procedure of analysis is presented for determining the dynamic instability and response of framed structures subjected to pulsating axial loads, time-dependent lateral forces, or foundation movements. Included in the analytical work are the instability criterion of a structural system, the finite element technique of structural matrix formulation, and the computer solution methods.

The dynamic instability is defined by a region in relation to transverse natural frequency, longitudinal forcing frequency and the magnitude of axial dynamic force. The axial pulsating load is expressed in terms of static buckling load for ensuring that the applied load is not greater than the …

Prebainitic Phenomena In Aisi 86b80 And 0.8c-5.3ni Steels, Chung Lim

Doctoral Dissertations

"An ultrasonic investigation shows that the prebainitic kinetics of AISI 86B80 and 0.8C-5.3Ni steels follow t^2/3 and or t¹ time laws in the lower bainite temperature region. The data analysis indicates that these kinetics signal carbon segregation to dislocations. The simple time laws are interrupted at the bainite start time. It is shown that at this time the carbon depleted regions around dislocations transform martensitically. The lower bainite reaction is thus initiated by the formation of supersaturated ferrite through carbon segregation and the subsequent local martensitic transformation"--Abstract, page iii.

Flowware -- A Flow Charting Method To Describe Digital Systems, Wayne Everett Omohundro

Doctoral Dissertations

"FLOWWARE is an interactive, graphical language to aid in the understanding and design of digital networks. The language is based upon the concept of flow charting. The user specifies the register layout of the system and the sequential operation in the form of a diagram on a graphics terminal. FLOWWARE makes full use of a local minicomputer to perform editing and drawing functions, and a remote large computer to perform translation and simulation. This division of labor allows the user to build his description off-line without having the remote computer program active"--Abstract, page ii.

Nucleate Boiling From Polymer Coated Surfaces., David Franklin Warner

Doctoral Dissertations

"This study consisted of an examination of both the effects of nucleate boiling on polymer coated surfaces and the effects of the polymer coated surfaces on the nucleate boiling curve. The nucleate boiling curve (the curve resulting from plotting heat transferred per unit area versus the temperature difference between the boiling surface and the liquid pool) of the polymer coated surfaces were compared with the nucleate boiling curve of gold-plated surfaces with no polymer coat and it was found that the thicker the polymer coat, the more the curve deviated from that of the metal uncoated surfaces.

All surfaces were …

Design And Operation Of A Microprogrammed Branch Driver For A Pdp-11 Computer., Lavon R. Biswell

Electrical and Computer Engineering ETDs

A Microprogramned Branch Driver (MBD) is the interface between Digital Equipment Corporation (DEC) PDP-11 series computers and a multicrate CAMAC system. The MBD is a microprocessor-controlled multiple, direct memory access (DMA) channel branch driver.

The requirements for an MBD are discussed in the introduction and stem from a Los Alamos Scientific Laboratory (LASL) study group report on the design of the Clinton P. Anderson Meson Physics Facility (LAMPF) data acquisition system. Because of the desire for the standard system, the types of experiments and data rates, and the varying complexity of the data acquisition systems, it was decided that a …

A Probabilistic Approach To The Design Of Heat Pipes, Charles C. Roberts Jr.

Mechanical Engineering ETDs

The design of heat pipes involves knowledge of phenomena such as surface tension forces, wick permeability, and fluid vaporization and condensation. Considerable variability in these phenomena has been observed in heat pipe experiments. Thus, a probabilistic design model for predicting heat pipe heat transfer rate has been developed taking into consideration uncertainty in the prediction of the above phenomena. The probabilistic model yields a mean, a standard deviation, and the distribution of heat transfer rate based on the means, standard deviations, and distributions of the design parameters. The probabilistic method is compared to experimental data from heat pipes with wire …

The Dynamic Response Of Continuous Beams And Plates, Robert L. Dineen

Civil Engineering ETDs

The objective of this investigation is to determine the complete response of undamped structural systems to time-dependent loads. Two systems, continuous beams and plates with equally spaced interior supports, are examined. Both have distributed mass and experience small linearly elastic deflections. The problems are formulated using the discrete mechanics method in which the response of a typical element of the system is first determined. A difference equation for the moments at the support locations is then derived by satisfying the force and compatibility conditions between adjacent elements. Finally, a closed form solution of this equation is obtained in terms of …

Elastic-Plastic Poisson's Ratio Of Borsic-Reinforced Aluminium Composites, Ronald Edward Allred

Nuclear Engineering ETDs

Poisson's ratio as a function of tensile strain has been examined for four volume fractions of unidirectional Borsic-reinforced aluminum composites. Linear relationships were found between Poisson's ratio and fiber volume fraction during Stage I (elastic filaments-elastic matrix) and Stage II (elastic filaments-plastic matrix) deformation which confirms that rule-of-mixtures equations may be used to predict Poisson's ratios for metal-matrix composites. These equations must be used with care, however, due to differences in the Poisson's ratio behavior of the components of the composite when tested alone and in situ in the composite. These differences are attributed to the triaxial stress field generated …

The Safety Barrier Dilemma, James H. Havens, Don L. Cornette, William M. Seymour

Kentucky Transportation Center Research Report

"Ran-off-the-road" fatal accidents currently account for approximately 65 percent of all freeway fatalities (1). Accordingly, ever-increasing emphasis has been given to the development of effective safety barrier systems, from guardrails to earth berms to median barriers to energy absorbing barriers and mires. However, highway designers have also recognized that safety barriers are hazards in themselves, misfits in the highway environment, and that they are items to be eliminated wherever possible. In a study of fatal accidents on the Interstate Highway System, it was found that fixed object collisions have been the leading source of fatalities, accounting for 43 percent …

Characteristics Of Outdoor Recreational Travel, Jerry G. Pigman, John A. Deacon, Robert C. Deen

Kentucky Transportation Center Research Report

The purpose of this investigation was to examine the characteristics of travel to outdoor recreational areas in Kentucky. Data were obtained by means of a license-plate, origin-destination survey at 160 sites within 42 recreational areas and by means of a continuous vehicle counting program at eight of these sites. A computer algorithm was developed for error detection and subsequent adjustment of the volume data as necessitated by occasional malfunction of the traffic recorders and vandalism. Vehicle occupancy was found to depend of the type of recreational area, distance traveled, and vehicle type. Occupancy increased with increasing distance and was greatest …

Tar Concrete Pavement Construction And Performance, Jerry G. Rose

Kentucky Transportation Center Research Report

In 1969, a 6.6-mile section of relocated KY 15 in Perry and Knott Counties was paved utilizing coal-tar (RT-12) concrete base and surface. This project was authorized under the Appalachian Regional Development Act of 1965 and was designated as experimental as a means of implementing a section of the Act.

Two nearby sections of KY 15, containing asphalt (PAC-5) concrete base and surface, were designated as control sections and used for comparison purposes. With the exception of the bituminous material, the experimental and control sections were purposefully made equal in all other respects. A design soil CBR of 9 was …

A Pavement Design Schema, James H. Havens, Robert C. Deen, Herbert F. Southgate

Kentucky Transportation Center Research Report

Elastic theory and 40 years of empirical flexible pavement design in Kentucky have been joined into the design system presented herein. A brief discussion is presented of the coupling mechanisms relating experience to theoretical analyses. An annotated design procedure is presented as a guide for pavement designers. Design nomographs account for a wide range of input parameters and permit the designer a wide choice of alternative thickness designs.

Mercury-Filled Settlement Gage, Tommy C. Hopkins, Robert C. Deen

Kentucky Transportation Center Research Report

A description is given of a remote sensing, multiple-point, mercury-filled settlement gage designed for measuring in-place settlements. The gage consists of settlement units positioned at locations where settlement measurements are desired and a monitoring unit located outside of construction limits. Settlement readings are observed on a mercury manometer located at the monitoring site and are· equal to the differences in initial and subsequent pressure head readings. Comparisons of measurements obtained at a highway construction site from mercury gage settlement units and conventional settlement platforms are presented and show very good agreement. With the mercury gage, a large amount of settlement …

Elements Of Median Design In Relation To Accident Occurrence, Gordon R. Garner, Robert C. Deen

Kentucky Transportation Center Research Report

The purpose of this study was to compare the accident histories of different median types and to provide verification of generally recommended median widths and slopes. A major limitation of the analyses was the small number of possible combinations of median width and cross slope available for study.

The analyses reported provided evidence from accident histories to support the general requirement that wider medians are safer medians. It was indicated that medians should be a minimum of 30-40 feet wide for high speed facilities and that flat slopes should be provided; 4:1 slopes are inadequate for medians less than 60 …

A Quantitative Analysis By Emission Spectroscopy Of The Metallic Constituents Of Biological Samples After Treatment By A Carcinogenic Agent, Charles R. Frydrych

Masters Theses

No abstract provided.

The Effect Of Porosity On Transverse Tensile Strength Of Filament Wound/Cvd Carbon-Carbon Composites., Gilbert William Brassell

Nuclear Engineering ETDs

Filament wound/CVD (Chemical Vapor Deposition) carbon­carbon composites have received considerable attention within the past few years due to desirable characteristics such as high heat of ablation, thermal shock resistance, strength improvement at elevated temperatures, and chemical inertness. However, poor mechanical properties in the trans­verse direction have hampered the total effectiveness of these composites in some applications and a study of the effects of porosity on transverse tensile strength of filament wound/CVD carbon carbon composites has been conducted.

Two types of filament wound/CVD carbon carbon composites were studied. A standard filament wound/CVD carbon composite, and a composite similar to the standard …

Kinetics And Dynamics Of Continuous Crystallization, Karichangal C. Parthasarathy

Chemical and Biological Engineering ETDs

A design correlation is presented for the prediction of steady state product size distributions resulting from a continuous crystal­lizer, based upon a single experimental determination. This has been accomplished by the definition of a new parameter called the "degree of crystallization," which has been related to the experimental nuclea­tion and growth rates in a salting-out crystallizer. The correlation resulted from the detection of variations in the suspension density of the mother liquor which has previously been assumed constant in cer­tain power law models. The degree of crystallization has also been described in terms of dimensionless number, length and area moments …

Conference System User's Guide, Rod L. Renner, United States. General Services Administration. Office Of Preparedness. Mathematics And Computation Laboratory.

Computerized Conferencing and Communications Center Reports

This paper describes three methods of group communication utilizing computer terminals as the vehicle for conducting a group discussion. The system that provides; these methods was developed by OEP for a UNIVAC 1108 as a convenient form of communication among geographically dispersed individuals and/or as an adjunct to oral communications. Completely normal language is used. Use of the computer permits maintaining a written record automatically and allowing discussions in which participants need not talk and listen in synchronism (in contrast to conventional meetings and telephone conference calls). In two of the methods, the discussants need not even be participating simultaneously. …