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Articles 481 - 510 of 711
Full-Text Articles in Engineering
An Experimental Determination Of The Effect Of The Axisymmetric Turbulent Wake On The Pressure Distribution On A Sphere, Martin Gardner Bowin
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 …
A Study Of Radiative Heat Transfer From A Spherical Layer, Hakimuddin Kalimuddin Khalil
A Study Of Radiative Heat Transfer From A Spherical Layer, Hakimuddin Kalimuddin Khalil
Masters Theses
"The problem of radiative heat transfer from a spherical layer of absorbing-emitting gas has been studied. First, the medium is assumed to be gray and then nongray. A thorough survey of literature from fields other than heat transfer, such as astrophysics and neutron transport has been made to stimulate further interest in this important area. To gain some insight into the effect of various parameters on the heat transfer, simple physical situations involving isothermal medium are considered. Comparison of the results obtained for the flux from the spherical and planar layers reveal that the curvature becomes increasingly important as the …
A Step-Wise Gray Approximation Of The Radiative Absorption Coefficient For An Isothermal Hydrogen Plasma, Keith Harlan Browne
A Step-Wise Gray Approximation Of The Radiative Absorption Coefficient For An Isothermal Hydrogen Plasma, Keith Harlan Browne
Masters Theses
"The radiative absorption coefficient of an isothermal hydrogen plasma is calculated using a step-wise gray approximation. The approximation retains a high degree of accuracy while significantly reducing the numerical computer time. The accuracy of the approximation depends on the spacing of the steps taken in the frequency spectrum as well as the number or steps used; 135 steps are used in this study. Plasma conditions of interest in this study are for temperatures between 5000 and 60,000ºK, densities between 10⁻⁵ and 10⁻⁷ gm/cm³, and thicknesses between 0.1 and 100 cm. Flux and intensity calculations are made for each case using …
Feed Drive Design For Numerically Controlled Machine Tools, Subash Bhatia
Feed Drive Design For Numerically Controlled Machine Tools, Subash Bhatia
Masters Theses
"The various types of feed drive control systems used in numerical control of machine tools have been broadly classified. Further a step by step design has been presented for the feed drive of a numerical contouring control milling machine. The aim has been to develop a consistent strategy for tackling a variety of such problems. Consequently stress has been laid on principles and not on design figures"--Abstract, page ii.
Magnetohydrodynamic Stability Of Laminar Flow In The Entrance Region Of A Parallel-Plate Channel, Thomas Eldon Eaton
Magnetohydrodynamic Stability Of Laminar Flow In The Entrance Region Of A Parallel-Plate Channel, Thomas Eldon Eaton
Masters Theses
"The hydrodynamic stability of laminar flow of an electrically conducting fluid flowing in a parallel-plate channel with an applied transverse magnetic field is investigated. The linear perturbation theory of hydrodynamic stability along with the assumption of low magnetic Reynolds number is applied to the governing equations to derive the governing rnagnetohydrodynarnic stability equation. A finite difference scheme is employed to numerically solve the magnetohydrodynamic stability equation. Neutral stability characteristics of the flow in the entrance region are obtained and presented. The neutral stability characteristics of the fully developed Hartmann flow are also re-examined and compared with those of a previous …
Interface Thermal Conductance With Metal Screens As Interstitial Material, William Edward Stewart Jr.
Interface Thermal Conductance With Metal Screens As Interstitial Material, William Edward Stewart Jr.
Masters Theses
"This thesis reports the results of an experimental investigation to determine the thermal conductance at the interface of metal specimens separated by wire mesh. Sets of metal specimens of copper, 2024-T4 aluminum, and 304 stainless steel were used. The specimens were cylindrical, axially aligned, and hydraulically loaded. All tests were conducted in an air environment. Pressure applied to the specimens ranged from 50 to 500 psig. Surface roughness of the interfaces varied from 5 to 20 micro inches. The wire mesh separators were of 304 stainless steel in 20, 30, 40, and 50 mesh. Results of the experiments show that: …
Influence Of Film Thickness On The Performance Of Solid Lubricants, Sunil Vishwanath Mahale
Influence Of Film Thickness On The Performance Of Solid Lubricants, Sunil Vishwanath Mahale
Masters Theses
"The object of this investigation was to determine the effect of lubricant film thickness on the coefficient of friction and on the wear life of solid lubricants. Bonded molybdenum disulphide and bonded graphite were the lubricants tested. Dow Corning's LFW-1 and Falex lubricant tester were the two machines used for testing these lubricants. The lubricants were sprayed on the specimen surface. Pretreatment, spraying and curlng were done according to standard or manufacturer's recommended procedures. During the entire research, the procedure for experimentation was followed according to ASTM No. 2625 on Falex and CRC recommendations on LFW-1 machine. It was found …
An Investigation Of Nucleate And Film Boiling Heat Transfer From Copper Spheres, William David Hardin
An Investigation Of Nucleate And Film Boiling Heat Transfer From Copper Spheres, William David Hardin
Doctoral Dissertations
"This study consisted primarily of a laboratory investigation involving nucleate and film boiling heat transfer from copper spheres with saturated liquid nitrogen at atmospheric pressure. An initial study was directed towards obtaining reproducible boiling heat flux versus ΔT curves in the nucleate boiling region from surface conditions created by single and/or multiple glass bead peenings. The variables of bead size, nozzle line operating pressure, and distance a copper surface should be placed from the nozzle outlet were checked. The results indicated that a final peening of the surface with 0.0017-0.0035 inch diameter glass beads, a nozzle line pressure of approximately …
Development And Application Of Cartesian Tensor Mathematics For Kinematic Analysis Of Spatial Mechanisms, Robert Myrl Crane
Development And Application Of Cartesian Tensor Mathematics For Kinematic Analysis Of Spatial Mechanisms, Robert Myrl Crane
Doctoral Dissertations
"The complexity of spatial mechanisms in themselves and the absence of an attractive analytical tool for their study has left this field of engineering analysis largely unexplored. In recent years several analytic methods have emerged. One of the most attractive of these is the tensor method. Literature surveys reveal that the tensor method is largely unexploited in the U.S.A., with regard to spatial mechanisms as well as simpler kinematic problems. The purpose of this work is to develop tensor mathematics for application to the kinematic analysis of spatial mechanisms. Methods are developed for position solutions and the determination of velocities …
Bound-Free Continuum Radiation From Non-Gray Nonisothermal Shock Layers, Chu Yih Wang
Bound-Free Continuum Radiation From Non-Gray Nonisothermal Shock Layers, Chu Yih Wang
Masters Theses
"This study investigates the continuum radiative flux from nonisothermal stagnation shock layers composed of atomic gases. The general equations for the composition are derived and the Rankine-Hugoniot equations are simplified and solved to give the thermodynamic conditions of the shock layers. To accurately model the stagnation shock layer, the plasma must be considered to be nonisothermal. In the current study, linear shock layer temperature profiles are assumed. Consequently, the fluid dynamics and the radiation are uncoupled. The radiation model assumes one-dimensional radiative energy transport and considers only continuum processes. The radiative flux is calculated by considereing ground to free state …
Mutually Dependent Heat And Mass Transfer In Laminar Tube Flow, Gary Alfred Scheffel
Mutually Dependent Heat And Mass Transfer In Laminar Tube Flow, Gary Alfred Scheffel
Masters Theses
"An investigation is performed of the mutually dependent heat and mass transfer in laminar and hydrodynamically fully developed gas flow in a tube. Sublimation of mass occurs at the tube wall so that heat and mass transfer take place between the wall and the flowing gas stream. The wall of the tube is thermally insulated from the external environment with the result that the heat of sublimation is supplied by convective transport from the gas. The solution of this problem requires the simultaneous consideration of the energy and diffusion equations, with coupling provided by the boundary conditions. Mathematical expressions are …
Vibration Of A Rotating Cantilever Beam With An Independently Rotating Disk On The Free End, Darrell Blaine Crimmins
Vibration Of A Rotating Cantilever Beam With An Independently Rotating Disk On The Free End, Darrell Blaine Crimmins
Masters Theses
"This thesis provides a vibration analysis of a rotating cantilever beam with an independently rotating thin circular disk on the free end. The exact differential equations of the system as defined by classical Bernoulli-Euler beam theory are written using the methods of the calculus of variations. The exact equations are not solved, but two different approximations are found by assuming a cubic polynomial deflection curve and applying the equation of Lagrange. The solutions are restricted to small deflections of the beam and a shaft stiffness which permits a deflection in only a single plane. Nonlinear differential equations result in the …
Analysis Of Elastic Thermal Stresses By Station-Function Collocation Methods, Jaw-Kuang Wang
Analysis Of Elastic Thermal Stresses By Station-Function Collocation Methods, Jaw-Kuang Wang
Masters Theses
"An approximate method for the solution of thermal stress problems is presented. The method makes use of polynomial approximations to reduce the partial differential equation to a system of linear algebraic equations or a set of first-order ordinary differential equations. This results in satisfying the differential equation at a finite number of stations. The boundary conditions are satisfied identically. Two examples of the method, presented in detail, indicate that the solutions of the biharmonic equation for the stress function and the Fourier equation for the temperature distribution have good accuracy with a minimum of labor. A generalized method is derived …
A Computer Simulation Of The Internal Ballistics Of Recoilless-Rifle Rocket Launchers, John Edd Mosier
A Computer Simulation Of The Internal Ballistics Of Recoilless-Rifle Rocket Launchers, John Edd Mosier
Masters Theses
"A computer program has been developed to simulate the basic mechanics and gas dynamics associated with launching a solid propellant rocket from a recoilless rifle. This program, entitled "KICKIT," may be used to predict the performance and evaluate many of the pertinent design parameters of both conventional recoilless rifles and a recoilless rocket launcher system. This program is a valuable analytical tool which enables the designer either to optimize the system design or predict the behavior of the system under off-design conditions"--Abstract, Page ii.
Use Of The Turbulence Kinetic Energy Equation In Prediction Of Nonequilibrium Turbulent Boundary Layers, William Madison Byrne Jr.
Use Of The Turbulence Kinetic Energy Equation In Prediction Of Nonequilibrium Turbulent Boundary Layers, William Madison Byrne Jr.
Doctoral Dissertations
"A differential method is proposed for the prediction of a broad range of turbulent boundary layers of engineering and scientific interest. A digital computer program is presented which is applicable to boundary layers with positive, negative, and zero pressure gradient in the main-stream direction as well as boundary layers with suction, blowing or zero mass addition at the wall. The turbulence kinetic energy equation is solved simultaneously with the longitudinal momentum and continuity equations to provide an independent means for determining the effective viscosity which makes allowance for "history" effects in the flow. It is shown that the prediction method …
Optimizing Diesel Engine Efficiency Using The Controllability Of A Variable Ratio Hydrostatic Transmission, Gordon Wright
Optimizing Diesel Engine Efficiency Using The Controllability Of A Variable Ratio Hydrostatic Transmission, Gordon Wright
Doctoral Dissertations
"A linear mathematical model of a diesel engine, hydrostatic transmission, and electric dynamometer system was developed. This model was used as an aid in designing a single input controller which regulates engine speed to optimize efficiency while maintaining constant transmission output speed under changing load conditions. Compensation was necessary to stabilize the system because of positive feedback in the engine control system. The compensated system's response was compared to that which was predicted analytically. The analytical model was then extended to design the control system parameters to operate the engine and transmission in a representative vehicle"--Abstract, page ii.
An Investigation Of The Stiffness Of Shafts With Integral Disks, Richard King Riley
An Investigation Of The Stiffness Of Shafts With Integral Disks, Richard King Riley
Doctoral Dissertations
"The results of an investigation of the effect of an integral disk on the torsional elastic stiffness of an axisymmetric shaft are presented. Various configurations of disk diameters and widths on a shaft of specified diameter were investigated, using a finite element method of calculation verified by experimentation. The finite element method is presented for the elastic solution of a general axisymmetric body under all possible axisymmetric load conditions. The axisymmetric body is idealized as an assemblage of triangular cross-sectioned torii representing both the normal and shear properties. The elastic stiffness is used to obtain the equilibrium equations of the …
Ionization Of Air Produced By Strong Shocks, Howard Sajon Joyner
Ionization Of Air Produced By Strong Shocks, Howard Sajon Joyner
Doctoral Dissertations
"This dissertation provides theoretical predictions along with experimental results for electron concentrations behind a shock as a function of Mach number over a range from 11 to 20 using a combustion driven shock tube operating in air. These theoretical predictions represent an upper bound for chemical equilibrium. The model for air was 78.0880% nitrogen, 20.949% oxygen, 0.0300% carbon dioxide, 0 .9300% argon, 0.0025%neon, and 0.0005% helium. Also the theory of a double diaphragm shock tube with corresponding pressure ratio vs. Mach number relationships is provided. A computor [sic] program using iterative techniques for a succinct presentation covering the modifications and …
On The Flow Near An Enclosed Rotating Blade In The Neighborhood Of The Ground, Tze-Lien Liang
On The Flow Near An Enclosed Rotating Blade In The Neighborhood Of The Ground, Tze-Lien Liang
Masters Theses
"The flow in the vicinity of an enclosed rotating blade near the ground was studied both analytically and experimentally. Experimental results were obtained by making pitot tube traverses across the face of the housing but gave only a qualitative indication of the velocity distribution. Tufts of strings were used to locate the flow directions in the vicinity of the ground and the housing. The two dimensional potential flow solution was found to yield unreasonable results for this flow configuration due to viscous and rotative effects. The three-dimensional Navier-Stokes equations were solved numerically by using the successive underrelaxation method. The results …
A Digital Computer Program For Studying Elasto-Plastic Structural Behavior Due To Cyclic Loading, Rameshchandra Chandulal Hazariwala
A Digital Computer Program For Studying Elasto-Plastic Structural Behavior Due To Cyclic Loading, Rameshchandra Chandulal Hazariwala
Masters Theses
"A computer program has been developed to study the behavior of plane stress structures under cyclic loading. Such phenomena as thermal ratcheting, alternate plasticity, shake-down and the Bauschinger effect may be considered. The incremental theory of plasticity has been used. The program deals with realistic conditions such as nonlinear strain hardening, nonlinear temperature distribution and occurrence of both compressive and tensile plastic flow. The concept of an average material property has been used. Thermal ratcheting of a beam subjected to a constant bending moment and a temperature cycle has been studied in detail. The analysis shows analytically that the rate …
A Transient Method Of Negligible Internal Thermal Resistance For Determining Thermal Contact Conductance In A Vacuum, Richard Chuka Oboka
A Transient Method Of Negligible Internal Thermal Resistance For Determining Thermal Contact Conductance In A Vacuum, Richard Chuka Oboka
Masters Theses
"A transient method for experimentally determining the interface conductance between metallic surfaces in contact is developed. The method applies the theory of negligible internal thermal resistance of one of the materials which form the interface. The method is applicable when the interface conductance is very low, a situation which exists when low conductance interstitial materials are used between contacting surfaces for purposes of thermal isolation. In this investigation, stainless steel wire screens of 10 and 100 mesh were used as interstitial materials between aluminum surfaces in a vacuum environment of 10⁻⁵ to 10⁻⁶ Torr. The interface pressure ranged from 40 …
Effect Of Surface Conditions On Nucleate Pool Boiling Of Refrigerant-11, Abbas M. Sinnarwalla
Effect Of Surface Conditions On Nucleate Pool Boiling Of Refrigerant-11, Abbas M. Sinnarwalla
Masters Theses
"The purpose of this investigation was to determine the effect of surface conditions on the heat transfer for nucleate pool boiling from flat horizontal surfaces. Experiments were carried out using Refrigerant-11 at atmospheric pressure as the test fluid with Inconel-600 as the heater material. The heat transfer coefficient was determined for mirror finished, chemically etched, glass beaded and sandpaper roughened heater surfaces over heat flux ranging for 0 to 18000 BTU/HR SQ FT. At a given heat flux, the heat transfer coefficient was found to be the lowest for mirror finished surface and the highest for sandpaper roughened surface"--Abstract, page …
A Study Of The Design And Construction Of A Full Scale Aircraft Component Demonstration Fatigue Test, Stephen Andrew Wright
A Study Of The Design And Construction Of A Full Scale Aircraft Component Demonstration Fatigue Test, Stephen Andrew Wright
Masters Theses
"The objective of this project was to design and build a full scale demonstration fatigue test for a Piper Aztec stabilator. A general discussion of the construction is included in this report. The Fourier series method of the aerodynamic theory of spanwise loading was used to determine the load distribution. The results show a close relationship with data furnished by Piper Aircraft Corporation. Fatigue theory is discussed in order to provide background for fatigue testing. The test specimen, methods and procedures of testing, known loading methods and systems, safety, etc., are discussed. Federal requirements for regulating and testing of aircraft …
Effect Of Inclination On Film Boiling, Shih-Chang Lin
Effect Of Inclination On Film Boiling, Shih-Chang Lin
Masters Theses
"The object of this investigation was to determine the effect of inclination on the heat transfer for film pool boiling. The test plate used as the heater was made of Inconel-600 and heated electrically. Liquid nitrogen at atmospheric pressure was used as the test fluid. The heater was oriented at various angles from the horizontal position with the heater surface facing both upward and downward and the heat transfer coefficient was determined for each angle over temperature differences ranging from 450ºF to 750ºF. As the heater angle was increased from 0º (horizontal) to 90º (vertical), the heat transfer coefficient increased …
The Design And Construction Of An Inertia Welder, Arthur Ferdinand Grimm
The Design And Construction Of An Inertia Welder, Arthur Ferdinand Grimm
Masters Theses
"The purpose of this investigation was the design and fabrication of a machine to bond metal to metal using the inertia method of friction welding. This method of bonding is considered far superior to the heretofore employed friction welding processes as will be explained later. The inertia method controls the energy imparted to the weld by using a flywheel which has been brought to a state of predetermined kinetic energy due to rotation. This energy is then transferred to the weld zone in the form of heat due to rotational friction. Hollow specimens with a cross-sectional area of 0.306 square …
Light Scattering As A Means Of Probing Particulate Systems, Arwind Krishna Gore
Light Scattering As A Means Of Probing Particulate Systems, Arwind Krishna Gore
Masters Theses
"The primary purpose of this investigation is to provide basic data needed in determining the size distribution of water-droplets in cloud chambers, sprays, dust clouds, etc. A critique of the classical Mie scattering theory is made to evaluate the influence of the properties such as size, shape and refractive index and of the particulate concentration on the scattering functions. Using He-Ne gas laser radiation of 6328 Å wavelength as the source, the angular intensity functions are tabulated for water-drops up to 20 microns in diameter, dispersed in air at 25ºC. A size interval of 0.2 microns and an angular interval …
Efficiency And Loss Mechanism Of The Electro-Fluid Dynamic Momentum Transfer Process Applied To Propulsion Systems Using Atmospheric Air As The Working Fluid, Roger Coy Crites
Efficiency And Loss Mechanism Of The Electro-Fluid Dynamic Momentum Transfer Process Applied To Propulsion Systems Using Atmospheric Air As The Working Fluid, Roger Coy Crites
Masters Theses
"The general equations governing EFD (electrofluid dynamic) flow are established, simplified, and solved in closed form to provide a mathematical model of an ideal EFD propulsion system. This mathematical model, in conjunction with an analysis of ion-neutral and neutral-neutral molecular collision phenomena, indicates that the cause of inefficiency in the EFD propulsion system is the system entropy increase associated with the diffusion of ion momentum through the neutral fluid. This loss mechanism is shown to be analogous to resistive heating losses in a constant voltage linear electrical network and can be minimized by obtaining minimum ion mobility. It is shown …
The Influence Of A Carbon Ablation Layer On Radiation From A Hydrogen Shock Layer, Birbal Singh
The Influence Of A Carbon Ablation Layer On Radiation From A Hydrogen Shock Layer, Birbal Singh
Masters Theses
"The effect of ablation heat shields on the radiative heat transfer to vehicles entering hydrogen atmospheres at thermo-dynamic conditions similar to those expected in Jovian atmospheres is investigated. The shock layer is assumed to consist of two plane parallel layers, one consisting of pure hydrogen species, and the other consisting of carbon species only. Each layer is assumed to be in local thermodynamic equilibrium at its respective temperature. The thermodynamic conditions in the hydrogen layer are arrived at by solving the Rankine-Hugoniot Equations across the shock. The temperature of carbon layer is taken as (3000, 5000, and 7000ºK) to cover …
Heat Transfer Through A Spherical Gas Shell, Adel Nassif Saad
Heat Transfer Through A Spherical Gas Shell, Adel Nassif Saad
Masters Theses
"The radiative transfer through an absorbing-emitting gas shell contained within black concentric spheres at uniform but different temperatures was investigated. A close form exact solution and an approximate solution were derived for the case of isothermal gas layer. The two solutions appear to compare well specially at low diameter ratios, and both agree with the radiative equilibrium solution in the thin limit. An approximate method was developed for the radiative equilibrium, non-isothermal gas layer, of the above problem. The method is based on the assumption of a hyperbolic emissive power distribution through the gas shell. The jump boundary conditions were …
Numerical Solutions Of The Torsional Oscillations Of A Shaft-Flywheel System, Mahendrakumar Ramkrishna Patel
Numerical Solutions Of The Torsional Oscillations Of A Shaft-Flywheel System, Mahendrakumar Ramkrishna Patel
Masters Theses
"The application of the finite-difference technique, the Fourier transform, and the Laplace transform for the solution of a system governed by the one-dimensional wave equation is examined. A specific example consisting of a continuous shaft-flywheel system acted upon by an exciting torque applied at a specific section of the shaft is studied. The exact solution to this example is obtained using the classical method of superposition of modes, and is used as a reference to evaluate the accuracy (in terms of the rms error) and relative efficiency (based on computer time) of three approximate solution methods. A sinusoidal excitation was …