Engineering Commons^™

Determination Of Thermal Contact Resistance Between Metals Using A Pulse Technique, William Edward Stewart Jr.

Doctoral Dissertations

"This dissertation reports the results of an experimental and analytical investigation to determine the thermal contact resistance of several metal specimen pairs using a relatively new pulse technique. Metal specimens were aluminum 2024-T3, aluminum 6061-T6, aluminum 7075-T6, copper 110, stainless steel 304, molybdenum, and Armco iron. Thermal contact resistance was also determined for dissimilar metal specimen pairs of aluminum 6061-T6 - copper 110 and aluminum 7075-T6 - copper 110. Aluminum 7075-T6, copper 110, and stainless steel 304 specimens were tested to determine the variance of contact resistance with time after loading.

Specimens were circular cylindrical disks between .033 and .061 …

Distributed-Network Realizations For The Simulation Of Partial Differential Equations, Roy Dale Hensley

Doctoral Dissertations

"A method is developed for the simulation of the partial differential equation

-u_xx + k_ou_tt + k_lu_t +k₂u = g(t)

for various boundary conditions. The boundary conditions are used to classify the problems into types and the Laplace transformed solution of the most general problem of each type is obtained.

Synthesis techniques are presented for the realization of circuits containing distributed networks that can be used to simulate the partial differential equation for given boundary conditions. Several heat flow and vibrating string examples are included to illustrate the application of the …

Mass Transfer With Second-Order Chemical Reaction Inside Circulating Fluid Droplets, Roy James Brunson

Doctoral Dissertations

"The solution of a mathematical model is presented which describes mass transfer accompanied by a second-order chemical reaction inside a circulating, fluid sphere for the laminar flow region. The values for eight different mass transfer indices are presented as a function of the Peclet number, reaction number, diffusivity ratio, concentration ratio, and the dimensionless contact time. The results of this work are compared with the film and penetration theories for mass transfer with reaction as modified to apply inside a fluid sphere. This work corrects the three factors which limit the accuracy of applying previous theories to fluid spheres: geometrical …

Grain Boundary Diffusion In Ionic Crystals, Kulwant Singh Sabharwal

Doctoral Dissertations

"The diffusion of ¹³¹I in single crystals and along the tilt grain boundaries of pure and calcium chloride doped (142±5 ppm) bicrystals of sodium chloride, grown by Czochralski technique, was investigated using a microtome sectioning technique. Results on bulk diffusion in pure NaCl agree well with the results of earlier investigators and are represented by the D=(504 cm²/sec)exp (-2.27 ev/kT). Enhanced diffusion of ¹³¹I is observed along the grain boundaries and the presence of the dopant lowers the grain boundary diffusivity over the entire temperature range of 430ºC - 570ºC studied in the present investigation. Thermal activation and electrical polarization …

Computer Assisted Teaching Of Steel Design, Wendelin Henry Mueller Iii

Doctoral Dissertations

"A method for use in creating a university level course is presented. The specifics of each of the steps is given in general terms to allow its application to as many different topics as possible. This method is then specifically applied in the formation of a fundamental steel design course using the American Institute of Steel Construction Specification. The reasoning utilized in each phase of development is documented. A lecture style presentation complemented by a series of student oriented computer programs was chosen for use. The details of the course material in outline form is given along with the computer …

Hydro-Thermal Generation Unit Commitment And Dispatch Using A Dynamic Programming Approach, Warren Dean Graham

Doctoral Dissertations

"The problem of thermal unit commitment is solved with dynamic programming. A practical example is given which solves the problem for a six generator system over a one year time span. This long range solution is used with a hydro optimization procedure to give an optimized hydro-thermal unit commitment solution. From this, a worth of hydro value is computed for each month, which may be used in the daily dispatching of thermal units and hydro. Applications of the program are also shown for aiding in generator maintenance scheduling and evaluating purchase power contracts with neighboring utilities. Error analysis is made …

Effects Of Cr-Plating And Environment On The Cracking Of Low Alloy Steels At High Temperatures, Robert C. Tooke

Doctoral Dissertations

"The cracking of low alloy Cr-Mo-V steels under cyclic stress at 1000-1100°C. was studied using a specially designed test apparatus. The results obtained from specimens plated with hard chromium are compared to those of unplated specimens. Tests conducted in gas mixtures of carbon monoxide and carbon dioxide showed that a high CO/CO₂ ratio retards cracking in both plated and unplated specimens. Both external and internal oxidation are used to explain these results. Inherent microcracks in the hard chromium plating promoted cracking in all CO/CO₂ environments. It was also found that these steels are severely embrittled in the presence …

An Experimental Investigation Of The Effects Of Ambient And Heated Steady Flow And Intense Sound Levels On The Response Of Acoustic Filter Elements, Raymond H. Schaffart

Doctoral Dissertations

"The primary purpose of this research was to investigate the effects of flow and finite amplitude waves on the response of acoustic elements. A further purpose was to evaluate the effects of elevated temperatures and cross-sectional dimensions on element performance. As an integral part of this work various laboratory techniques were explored for their suitability.

Empirical models for the acoustic impedance of side branch resonators were developed for the two operational modes, i.e., flow past the resonator and finite amplitude wave inputs. A description of the complex variation of the acoustic resistance of the resonator with flow past and variable …

Secondary Techniques For Increasing Fault Coverage Of Fault Detection Test Sequences For Asynchronous Sequential Networks, Lewis Ronald Hoover

Doctoral Dissertations

"The generation of fault detection sequences for asynchronous sequential networks is considered here. Several techniques exist for the generation of fault detection sequences on combinational and clocked sequential networks. Although these techniques provide closed solutions for combinational and clocked networks, they meet with much less success when used as strategies on asynchronous networks. It is presently assumed that the general asynchronous problem defies closed solution. For this reason, a secondary procedure is presented here to facilitate increased fault coverage by a given fault detection test sequence. This procedure is successful on all types of logic networks but is, perhaps, most …

An Exact Analysis Of Two-Dimensional Radiative Transfer In An Absorbing And Emitting Gray Medium, William F. Breig

Doctoral Dissertations

"The exact formulations for the radiative flux and the emissive power are presented for a two-dimensional, finite, planar, absorbing and emitting, gray medium in radiative equilibrium. Exact expressions are obtained for the medium subjected to the following types of boundary conditions: (1) cosine varying diffuse, (2) cosine varying collimated, (3) constant temperature strip, and (4) the strip illuminated by a uniform collimated flux. The solutions for the physically unrealistic cosine varying models are used to construct the solutions for the more practical finite strip models. The two-dimensional equations are reduced to one-dimensional equations by the method of separation of variables. …

A Monte Carlo Calculation Of Neutron Reflection From Various Curved Surfaces, Charles Jack Kalter

Doctoral Dissertations

"Plane parallel neutron beams normally incident upon the curved surface of a solid reflector are studied with the Monte Carlo method. The geometries studied are cylindrical, parabolic, and hemispherical. It is shown that when the curved surface is cylindrical, a small "focusing effect" occurs in the reflected neutron beam. Parabolic and hemispherical surfaces do not show "focusing". A study of the factors which determine the spatial dependence of the reflected flux shows that the probability of emergence of a neutron, traveling a fixed distance from a point inside the reflector, depends upon the curvature of the surface. It is only …

Continuous Interfacial Polycondensation Of Nylon 6-6, Chandrakant A. Patel

Theses

Nylon 6-6 has been prepared by continuous interfacial polycondensation from hexamethylene diamine and adipyl chloride in a stirred system. The effect of monomer concentration and stirring on the intrinsic viscosity of polyamide 6-6 solution in formic acid (90%) was determined.

As stirring rate and monomer ratio increased, the intrinsic viscosity and polymer yield went through a maximum. Diffusion coefficient (D_AB) for hexamethylene diamine was calculated and from that J_D and mass transfer coefficient /D_AB were calculated. A relation between Reynolds number and J_D factor was established by correlation curve.

Comprehensive Calculations Of The Parameters Describing Proton Energy Loss In Matter, Joseph F. Janni

Nuclear Engineering ETDs

Extensive calculations have been made of the mean energy loss, pathlength, range, multiple scattering, and pathlength straggling of protons in many materials. Emphasis has been placed on obtaining accurate results, especially for heavy materials and protons of very low energy. Values of the energy loss between .01 and 1.0 Mev were obtained by smoothing and interpolating experimental information. Above 1.0 Mev, the Bethe equation with all the necessary shell corrections has been used. Values of the adjusted ionization potential have been determined by least squares fitting the Bethe equation to all available energy loss data. The polarization effect has been …

Free Vibration Of Plates Stiffened By Parallel Ribs., Charles Edward Bacchus

Civil Engineering ETDs

A method is presented to obtain the natural frequencies and related mode shapes of certain types of stiffened plate systems. Dynamic stiffness matrices, based on ordinary assumptions in beam and plate theory, are derived to relate the displacements at the edges of a system element to the edge forces. Both in-plane and transverse forces and displacements are considered. Compatibility and equilibrium conditions at the intersections of plate panels and stiffening elements are employed to derive the governing equations of the system.

For general systems, the result is a set of linear homogeneous algebraic equations which must be solved by trial-and-error. …

Theoretical And Experimental Study Of Explosive Closures Of 6061-0 Aluminum Pipes, Lyle E. Edwards

Mechanical Engineering ETDs

This thesis examines the use of explosives to collapse metal pipes from an applications point-of-view. A particular system is studied, both theoretically and experimentally, in order to facilitate the future design of such closures with the least possible physical testing. The calculations are based on a rigid-perfectly plastic model of the observed deformations of the tubes, and on various assumed am derived properties of the metal and sheet explosives under the dynamic conditions of closure. A computer program has been devised which simulates the actual motion of a pipe during collapse. Experimental work involved actual test firing of aluminum cylinders …

Techniques For Active 3he Activation Analysis For Carbon And Oxygen, William Mort Sanders

Nuclear Engineering ETDs

The surface and body concentrations of carbon and oxygen have been measured in various materials using ³He activation. Channeling techniques have been used to differentiate between interstitial and substitutional location of these impurities.

Thin target excitation functions were determined for (³He,p) reactions with carbon and oxygen over a ³He energy range from 2.5 to 9.0 MeV. These data were used to calculate the activation curves for various combinations of incident particle energy, impurity distributions, and material.

Information on several computer codes used during this study is presented.

Computer Solution To Inverse Problems Of Elliptic Form: V²U(X,Y) = G(A,U,X,Y), Frederick Alvin Jeter

Dissertations and Theses

One important aspect of our present age of monolithic high speed computers is the computer's capability to solve complex problems hitherto impossible to tackle due to their complexity. This paper explains how to use a. digital computer to solve a specific type of problem; specifically, to find the inverse solution of a in the elliptical equation V²U(x,y) = g(a,U,x,y), with appropriate boundary conditions. This equation is very useful in the electronics field. The knowns are the complete set of boundary values of U(x,y) and a set of observations taken on internal points of U(x,y). Given this information, plus …

Current Mechanical Fastener Specifications And Test Procedure, John Fraczek

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Pavement Roughness Measurement And Evaluation, Rolands L. Rizenbergs, James L. Burchett, Larry E. Davis

Kentucky Transportation Center Research Report

Vertical accelerations of a passenger in an automobile are automatically summed while traveling a section of road at 51.5 mph. A roughness index is obtained by summing the accelerations and dividing by the time elapsed during the test. The index is subjectively related to the riding quality of pavements. Continuity in measurements since 1957 has been preserved through correlations among successive vehicles involved and reference pavements.

In general, bituminous construction has yielded smoother-riding surfaces than concrete construction. No major improvements in construction were noted on bituminous pavements since 1962. The ride quality of concrete pavements, however, has improved on those …

Kentucky Pavement (Bituminous) Performance Evaluations And Design Studies, James H. Havens

Kentucky Transportation Center Research Report

No abstract provided.

Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

Lattice parameters, thermal expansion coefficients, and Grüneisen parameters of tungsten are determined by an x-ray method in the temperature range of 180-40 K without the use of liquid gases. Lattice parameters are expressed as a function of temperature. Thermal-expansion coefficients decrease with temperature and show no anomaly in contrast to a hypothesis proposed by Featherston and Neighbours. Grüneisen parameters γ are decreasing with temperature in accordance with the theoretical predictions. © 1971 The American Institute of Physics.

Field Identification Of Soils And Aggregates For County Roads, D. G. Shurig, Jean E. Hittle

Indiana Local Technical Assistance Program (LTAP) Publications

The primary purpose of this bulletin is to provide instruction to Indiana county road personnel on rating the quality of soils and pit-run materials used in the construction and maintenance of county roads. A system of soil classification is presented which provides the county highway engineer, road supervisor and inspector alike, with a common language for identifying soil types, properties and problems.

The Lure Of Home, Tim Brady

Publications

This article recounts an aircraft accident that could have been avoided. The pilot ignored flight manual warnings to not fly in icing conditions. The pilot disregarded all advice to stay on the ground but he was anxious to get home and celebrate an occasion with his family. All lives lost on the flight.

The Effect Of Variable Properties On The Laminar Flow Of Gases, Norman Shilling

Dissertations

The problem of heat transfer in laminar flow of a gas through a constant diameter cylindrical tube is treated. The gas is cooled by the tube walls held at constant temperature. Two tube inlet conditions are considered: (1) fully developed velocity and uniform temperature profiles (Graetz boundary condition) and (2) uniform velocity and temperature (UTV) profiles. Results of the theoretical and experimental phases of the work are presented.

The theoretical solution is based on the compressible boundary layer equations with varying transport and thermodynamic property terms retained. For the Graetz condition, an existing finite difference solution scheme is modified for …

The Pennsylvania State University

ACUTA: Other Publications

Attached is a draft of the charter membership 'letter we discussed at the meeting in Chicago last week. PLEASE. I have no special "pride of authorship" in this type of thing, so I implore you to be ruthless in your criticism, additions, deletions, etc. We want to entice a good membership drive, not put laurels on my head. So, if you'll go over this, make comments and return to me just as soon as possible, I compile the comments, prepare the final copy and have it printed.

Durability Of Traffic Paint On Portland Cement Concrete Pavements, Assaf S. Rahal

Kentucky Transportation Center Research Report

Performance of a series of transverse lines applied to a relatively new concrete pavement, utilizing primes and pretreatments, is reported. The report includes descriptions of the location of test lines and types of paint and pretreatments, performance histories, and analysis of results. Chlorinated rubber, epoxy, and urethane paints were the most durable. Neither pretreatment nor the use of primes significantly increased durability.

Holidays From Danger, Tim Brady

Publications

A reminder to be safe during holidays to prevent fires, avoid personal injury, and stay off the roads after drinking.

Dielectric Properties Of Atactic And Isotactic Polystyrene, Thaddeus F. Kroplinski

Theses

The purpose of this investigation was to determine the dielectric constant and dissipation factor of atactic and isotactic polystyrene at 25°C and at frequencies of 0.1, 1.0, 10, and 100 kilocycles per second. In addition, the effects of molecular weight and crystallinity on the dielectric properties of polystyrene mos also studied.

Polystyrene slabs of uniform thickness mere prepared by molding the polymer under heat and pressure. The isotactic polystyrene slabs Imre annealed at 175°g for various lengths of time to achieve varying degrees of crystallinity.

The molded polystyrene slabs were fitted with circular aluminum foil electrodes to form a three …

Front Matter, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

Turbulent Interface Detector Using A Multiple Array Of Single Hot Wires, W. H. Schwarz

Symposia on Turbulence in Liquids

Intermittency circuits can be used to experimentally determine some of the properties of the turbulent interface that occur in turbulent shear flows. The signal I(x,t) is unity if turbulence is present at x and zero otherwise. Using the signals obtained from detectors at one or more points, certain statistical measures of the interface position Y(x,t) can be determined. Also using a linear array of conventional single hot-wire probes, the position of the interface can be detected continuously to within some small error. The intent of this h-detector is similar to the wave-height detector used in studies of sea surfaces. The …