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Articles 511 - 540 of 696
Full-Text Articles in Mechanical Engineering
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 Some Interstitial Materials On The Thermal Contact Conductance, Jin-Tyan Lin
Influence Of Some Interstitial Materials On The Thermal Contact Conductance, Jin-Tyan Lin
Masters Theses
"Experiments have been conducted to investigate the effect of the interstitial materials at the interface of metals in contact. The test specimens were cylinders, axially aligned and loaded. Specimen materials were 606l-T6 aluminum alloy, and the contact fillers were stainless steel wire screens, aluminum foil, paper, and dielectric greases. The tests were conducted at atmospheric environment. The contact pressure ranged from 25 psi to 600 psi. The mean interface temperature ranged from 100 ºF to 200 ºF. Surface roughnesses of specimens were from 25 to 35 micro-inches, rms. The results of the investigation reveal that if the contact surfaces are …
Dynamic Analysis Of A Torsional Vibration Actuator, Narayandas Trikamdas Ashar
Dynamic Analysis Of A Torsional Vibration Actuator, Narayandas Trikamdas Ashar
Masters Theses
"The objective of this study is the evaluation of a mechanical system, which includes a Hooke's joint, as a possible torsional vibration actuator. The essential requirement of such a system is to produce a periodically varying angular motion superimposed upon a mean constant speed rotation. The basic kinematics of a Hooke's joint suggest that it could be used to generate the type of motion desired. The mechanical arrangement of a system incorporating a Hooke's joint is described and the governing differential equations are developed. These equations are simultaneous, differential equations of second order and are highly nonlinear. Values of typical …
Transient Response Of A Vibration Isolation System, Hemendra Shantilal Acharya
Transient Response Of A Vibration Isolation System, Hemendra Shantilal Acharya
Masters Theses
"A practical procedure for investigating the performance of a vibration isolation system under transient conditions is presented. For this investigation, an induction motor with an unbalanced rotor is studied during the period when it accelerates to its operating speed from rest. Using Newton's second law of motion, equations of motion are derived, first neglecting and then considering the effect of "inertia torque". This torque is produced by the inertia force resulting from vertical acceleration of the unbalanced mass. The equations are solved on a digital computer using the Runge-Kutta method of order 4. The results obtained are compared with those …
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 …
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 …
The Analysis Of R-S-S-R Spatial Four-Bar Mechanism, David Perng Chyi
The Analysis Of R-S-S-R Spatial Four-Bar Mechanism, David Perng Chyi
Masters Theses
"Although many methods are known for the kinematic analysis of spatial mechanisms, such as descriptive geometry, vector analysis, dual number theory, matrices, screw calculus, and various other methods, a better way to analyze the specific R-S-S-R four-bar mechanism is to use tensor methods in order to eliminate the apparently formidable and tedious tasks of mathematically formulating problems and obtaining solutions. The analysis described in this paper is developed basically by using tensor notations and operations, and the calculations take advantage of the capabilities of modern digital computers. A FORTRAN program for the IBM 360 Data Processing System which will analyze …
Method For Optimizing Multi-Layer Insulation, William Donald Morath
Method For Optimizing Multi-Layer Insulation, William Donald Morath
Masters Theses
"The use of multi-layer insulation can result in reduced material cost, weight, or volume. A method for selecting layer materials is described. Each layer material is selected to operate at its upper temperature limit and to contribute to the overall performance of the wall. The analyses required for optimizing flat and cylindrical walls are developed. Use of the digital computer makes it feasable [sic] to select layer materials from a large group of candidates. Fortran IV programs for optimizing flat and cylindrical walls are presented, and their use is demonstrated by the solution of example problems. Methods for improving the …
Design Of R-C-C-R Spatial Mechanism, Kao-Chien Hsei
Design Of R-C-C-R Spatial Mechanism, Kao-Chien Hsei
Masters Theses
"An analysis to design a particular R-C-C-R spatial mechanism was developed using tensor notations and operations. This specific R-C-C-R spatial mechanism can be used to couple two shafts intersected at a skew angle with constant rotating speed ratio. This skew angle, or bending angle of the two shaft, may vary from 30 up to 180 degrees. The governing equations of relative positions of the mechanism were formulated as a function of two variables: the bending angle of the shafts and the rotating angle of the input link. To exemplify the various design conditions, the design parameter versus the bending angle …
Analysis Of A Water Level Control, Bhupendra Girdharlal Shah
Analysis Of A Water Level Control, Bhupendra Girdharlal Shah
Masters Theses
"This thesis presents the analysis of a controller for a liquid level control system. The controller was built using an analog computer providing the ability to easily construct up to three modes of control. The controllers analyzed were: 1.) Proportional, 2.) Proportional plus reset, and 3.) Proportional plus reset plus preact. The system was tuned experimentally to provide satisfactory operation and root loci were also plotted to show the system stability for the three modes"--Abstract, page ii.
Film Boiling From Inclined Flat Surfaces, Charles Ernest Price
Film Boiling From Inclined Flat Surfaces, Charles Ernest Price
Masters Theses
"The object of this investigation was to determine the effect of inclination on the heat transfer for saturated film pool boiling from a flat plate heater. Nitrogen at atmospheric pressure was used as the test fluid. The test plate was oriented at various angles from the horizontal position and the convective film coefficient was determined for each angle. Tests were conducted for heater angles of 0°, 30°, 60°, and 90°. The heater strip was placed in a container of the liquid and was heated electrically. Heat transfer results were obtained for plate temperatures ranging from 100 to 800°F. As the …
A Computerized Method For Finding The Dynamic Response Of Multi-Mass Systems With Damping To Arbitrary Inputs, Bakulesh Balbhadra Patel
A Computerized Method For Finding The Dynamic Response Of Multi-Mass Systems With Damping To Arbitrary Inputs, Bakulesh Balbhadra Patel
Masters Theses
"A practical procedure for the systematic application of Foss's method to the solution of multi-degree-of-freedom damped systems is presented. It is relatively easy to determine the response of classically damped systems to various inputs. For non-classically damped systems the method proposed by K. A. Foss has been employed. This method gives an exact and complete solution for the response of linear multi-mass damped systems subjected to arbitrary inputs. Since the method requires lengthy and complex computations, the use of a digital computer is essential. In order to obtain the complete response of a multi-mass damped system to both sinusoidal and …
Apparatus And Techniques For The Plane Wave Analysis Of Acoustic Filters, Victor Hugo Simon
Apparatus And Techniques For The Plane Wave Analysis Of Acoustic Filters, Victor Hugo Simon
Masters Theses
"This thesis describes a method for determining the reflection and transmission characteristics of acoustic filters under static (i.e. no flow) conditions. These characteristics are obtained by the combination of linear plane wave acoustic theory with a sequential experimental procedure. The experimental data necessary for the calculation of the reflection characteristics were obtained from measurements made on the inlet side of the filter with a standing wave tube apparatus. In order to calculate the transmission characteristics of the filter, the standing wave measurements were augmented with measurements taken on both the inlet and outlet side of the filter. This was accomplished …
Investigation Of Free Convection Heat Transfer From An Inclined Flat Plate, Phairojna Sang-Urai
Investigation Of Free Convection Heat Transfer From An Inclined Flat Plate, Phairojna Sang-Urai
Masters Theses
"The experimental investigation was conducted to determine temperature distribution and convective heat transfer coefficients in terms of Nusselt number for an inclined heated flat plate in air. The heated surface of the aluminum flat plate was set facing upward and moved through seven positions from the vertical to the horizontal. The investigation shows that the local Nusselt number can be predicted by Kiekus's solution within 12 per cent for inclination angles from the vertical through 75° from the vertical. In the case of the vertical position, Eckert's solution gives a better prediction. For the horizontal position the results show good …
Application Of Approximate Transmission Matrices To Describe Transverse Beam Vibrations, Ranjit Kumar Roy
Application Of Approximate Transmission Matrices To Describe Transverse Beam Vibrations, Ranjit Kumar Roy
Masters Theses
"This paper is a report of an investigation of an approximate method for finding the principal mode frequency roots for beams in transverse vibration. The method utilizes approximate transmission matrices obtained by a power series expansion of the basic differential equation which governs the transmission matrix. Investigation has been carried out to examine the efficiency of the method in producing the first several normal mode frequency roots. This has been achieved by applying the method to several uniform and non-uniform beams and comparing the results with the exact solutions. The technique has further been applied to non-uniform beams of tapered …
A Theoretical Analysis Of The Free Vibrations Of A Clamped Circular Plate With Damping, Bhalchandra Krishnaji Vaidya
A Theoretical Analysis Of The Free Vibrations Of A Clamped Circular Plate With Damping, Bhalchandra Krishnaji Vaidya
Masters Theses
"A theoretical analysis of the free vibrations of a clamped circular plate was undertaken. The effects of transverse shear were considered for application to relatively thick plates in which there exist sharp transients and frequencies corresponding to higher modes. The method adopted by R. D. Mindlin was used to develope [sic] the differential equation of motion for the plate. The damping effect due to the resistance of the medium in which the plate vibrates was also considered. This damping was assumed to be due to the generation of pressure waves caused by the displacement of the plate...Since the solution requires …
The Use Of Turbulence Energy Equation In Boundary Layer Study, Ro-Chi Tai
The Use Of Turbulence Energy Equation In Boundary Layer Study, Ro-Chi Tai
Masters Theses
"A turbulent boundary layer problem has been studied analytically and compared with an available experiment in the literature. Correlations of the experimental data were made to investigate the validity of the commonly used empirical relations on turbulent shear stresses. It was found that the model which related the local turbulent shear stress linearly with the local turbulent kinetic energy, as used by Bradshow et. al., appeared to be most reasonable. combining this model with the expression of turbulent viscosity given by Boussinesq, it was then possible to introduce the turbulence-energy equation in addition to the governing equations of continuity and …
Experimental Determination Of Dynamic Properties Of Aluminum Including Poisson's Ratio, Terry Lee Holman
Experimental Determination Of Dynamic Properties Of Aluminum Including Poisson's Ratio, Terry Lee Holman
Masters Theses
"Two rods of 7075-T651 aluminum are longitudinally impacted to investigate the material's dynamic properties. The test rod, initially at rest, is instrumented with strain gages to record the strain-time history after the impact rod, accelerated to uniform velocity by an air gun launcher, strikes the test rod. A camera records the strain-time pattern displayed on an oscilloscope. The experiment indicates a consistent rise time of approximately 9 µsec. Simple one-dimensional theory correlates well with the experimental data. Compensation is included for the transverse sensitivity of the gages used. The dynamic values for both the modulus of elasticity and Poisson's ratio …
A Comparison Of Lumped Parameter Models Commonly Used To Describe One-Dimensional Vibration Problems, Suresh Kumar Tolani
A Comparison Of Lumped Parameter Models Commonly Used To Describe One-Dimensional Vibration Problems, Suresh Kumar Tolani
Masters Theses
"Three lumped parameter model representations of the one-dimensional uniform continuous system in a vibration state are examined. The exact (continuous) solutions were used as a reference to evaluate the accuracy of the results obtained via these discrete element models. The model comparisons, carried out for both the principal modes and the systems under forced excitations, are based on the maximum strain energy. The effect of varying the number of segments in the model representation showed improvement in approximating the exact strain energy solution as the number of segments was increased. In general, the results of the model comparisons based on …
Dynamic Response Of A Gyrocompass, Subhash Govind Kelkar
Dynamic Response Of A Gyrocompass, Subhash Govind Kelkar
Masters Theses
"A gyrocompass with three degrees of freedom is studied and an attempt made to solve the exact equations of motion numerically. The equations are obtained by using the Lagrange formulation of the problem. The kinetic energy and the potential energy of the system are determined from the energies of the various components. These are then substituted into Lagrange's equation to obtain the three equations of motion for the three angular coordinates. As few restrictive assumptions as possible are made during this development. From these exact equations of motion an approximate analytical solution is obtained by making several assumptions and then …
The Design Of A Direct Current Generator Field Controller, Melvyn Elwin Downs
The Design Of A Direct Current Generator Field Controller, Melvyn Elwin Downs
Masters Theses
"A controller was built utilizing transistors and silicon controlled rectifiers to allow torque control of the General Electric dynamometer, type TLC-50. The current gain of the controller was approximately 10⁶ such that the field current could be controlled by an input current of zero to approximately two microaaperes. The transfer function for the controller-dynamometer system was experimentally determined. The results indicate that the gain of the open loop torque control system is constant for frequencies up to 1.1 radians per second. Satisfactory values of gain for proportional and proportional plus integral control, were experimentally determined by operating the closed loop …
Analytical And Experimental Methods For Determining The Properties Of Materials At Very High Rates Of Loading, A. G. Behring
Analytical And Experimental Methods For Determining The Properties Of Materials At Very High Rates Of Loading, A. G. Behring
Masters Theses
"In the following report, some of the properties of ALCOA 7075 T651 aluminum, when subjected to high rates of loading, are experimentally investigated by impacting two rods of the material longitudinally. One rod is accelerated to a uniform velocity with an air gun launcher. The stationary second rod is instrumented with strain gages on its lateral surface in order to determine the strain-time history following impact. A detailed description of the experimental equipment is included. Simple, one-dimensional theory is used to determine the dynamic, elastic modulus of the test material under the impact condition. Several observations regarding the behavior of …
A Study Of Swirling Air Flow In A Converging Nozzle, Charles William Lineberry
A Study Of Swirling Air Flow In A Converging Nozzle, Charles William Lineberry
Masters Theses
"A study was conducted to determine the behavior of swirling air flow in a converging nozzle. Special instrumentation was constructed to obtain radial traverses of the flow at four axial positions. the data collected consisted of velocity, static pressure, and stagnation temperature. The flow pattern demonstrated the Ranque-Hilsh effect and reversed axial flow in the core region. As the flow entered the nozzle, it had the characteristics of a free vortex. At the exit plane the characteristics were those of a forced vortex. The converging nozzle caused an increase in the magnitude of the axial velocity component"--Abstract, page ii.
An Experimental Method Of Determining The Thermal Accommodation Coefficients Of Metallic Surfaces, Raymond John Dethorne
An Experimental Method Of Determining The Thermal Accommodation Coefficients Of Metallic Surfaces, Raymond John Dethorne
Masters Theses
"In the free molecule regime, Knudsen number greater than 10, heat is transferred from a solid by radiation and conduction. The ability of a surface to emit radiant energy is governed by a surface property called emittance while the surface property which apparently regulates the amount of heat transferred by conduction is called the thermal accommodation coefficient. This thesis presents the results of an experimental investigation to determine a relationship between these two properties, emittance and thermal accommodation coefficient. A test apparatus was constructed to measure both the radiation and conduction contributions between two concentric cylinders. cylinders of aluminum and …
Investigation Of Thermal Resistance At The Interface Of Dissimilar And Similar Metals, Ching-Liang Lin
Investigation Of Thermal Resistance At The Interface Of Dissimilar And Similar Metals, Ching-Liang Lin
Masters Theses
"Experiments have been conducted to investigate the resistance and the effect of the directional heat flow at the interface of metals in contact. The test specimens were cylinders, axially aligned and dead weight loaded. Specimen materials were aluminum, bronze, and steel. The tests were conducted at environment pressures of 5x10⁻⁵ Torr. or less. The dead weight load was kept at 10 lbs. for all tests and the surface roughness for all specimens was from 6 to 8x10⁻⁶ inch. The results of the investigation reveal that the resistance to heat flow at the interface of metals decreases as the interface temperature …
Instrumentation Of A Shock Tube Facility, James Everett West
Instrumentation Of A Shock Tube Facility, James Everett West
Masters Theses
"The theory of schlieren and interferometer systems was described and related to studies of shock waves in a shock tube. An interferometer was procured and a schlieren system was modified for use with the UMR shock tube facility. The design and construction of a base for the systems and window assemblies for the shock tube comprised the major portion of the work on this project. A short series of tests were run to ascertain the compatibility of the instrumentation to the UMR shock tube facility. While no schlieren photograph of the shock wave was obtained, the system was shown to …
Constant Horizontal Force Machining Through Flash Welded Steel Bars Of Varying Hardness, Donald Naeger
Constant Horizontal Force Machining Through Flash Welded Steel Bars Of Varying Hardness, Donald Naeger
Masters Theses
"The purpose of this experiment was to determine the effect of a constant horizontal force applied to the carriage of a lathe as it turned a piece of stock which consisted of two steel bars, of different hardness, flash welded together. This experiment was performed on a lathe to which a pulley system with a mechanical advantage of six was attached to the carriage. The strain on the tool was measured both in the horizontal and vertical directions by a tool dynamometer on which eight strain gages were mounted. The strain gages were calibrated on a Tinius-Olsen testing machine. The …
Coupled Transport Of Heat And Mass In Laminar Tube Flow, Lung-Mau Huang
Coupled Transport Of Heat And Mass In Laminar Tube Flow, Lung-Mau Huang
Masters Theses
"The object of this investigation is to study the mutual dependence of heat and mass transport in laminar and hydrodynamically developed tube flow. Consideration is given to gas flow through a tube whose wall is coated with a sublimable materials so that heat and mass transfers take place between the wall and the flowing gas stream. The tube wall is thermally insulated from the external environment, with the result that the latent heat required by the sublimation process at the wall is supplied solely by convective transfer from the gas. The analysis of the problem requires simultaneous solution of the …