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Dissertations and Theses

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Articles 121 - 130 of 130

Full-Text Articles in Mechanical Engineering

Liquid Transmission Line Pulser Circuit For Laser Excitation, Carl Stultz Jan 1983

Liquid Transmission Line Pulser Circuit For Laser Excitation, Carl Stultz

Dissertations and Theses

The subject of this thesis is the study of liquid dielectric transmission lines and their potential application as an excitation source in high speed, high-repetition rate laser designs. The design problems associated with the construction of high repetition rate (khz), short wavelength lasers have been reviewed and the major shortcomings of conventional electrical driving circuits identified. The identification of these shortcomings and a review of the available literature on electrical circuits for various types of lasers suggested that liquid dielectrics and transmission lines could potentially have significant advantages over more conventional circuitry used in high repetition rate, short wavelength lasers. …


Investigation Of Blood Pressure Measurement Using A Hydraulic Occlusive Cuff, Kusha R. Bhattarai Jan 1982

Investigation Of Blood Pressure Measurement Using A Hydraulic Occlusive Cuff, Kusha R. Bhattarai

Dissertations and Theses

This thesis presents an improved oscillotonometric system for the measurement of human blood pressure. The study included:

1. The design of a hydraulic occlusive cuff,

2. The investigation of the wave forms taken from the blood pressure measurements, and

3. The design of a mechanism for the simulation of human blood pressure pulse.

In this study, an experimental system consisting of a rigid shell occlusive cuff, a constant volume displacement pump, a transducer, and a chart recorder was designed and used for data collection.


Experimental Determination Of Post-Buckling Performance Of Steel Angles, Rupasiri Purasinghe Sep 1981

Experimental Determination Of Post-Buckling Performance Of Steel Angles, Rupasiri Purasinghe

Dissertations and Theses

An experimental testing program was conducted to determine the compression member performance in post-buckling region. These results are compared with an analytical computer program developed by Portland State University under Bonneville Power Administration Contract 79-80BP 24005. The paper presents the sensitivity of the performance of single angle compression members to various parameters such as length to radius of gyration ratio, eccentricity, end conditions and yield stress. The effect of local buckling on long member performance is also documented.


Reduction Of Capacitor Switching Transients By Controlled Closing, John Herman Brunke Jan 1980

Reduction Of Capacitor Switching Transients By Controlled Closing, John Herman Brunke

Dissertations and Theses

This thesis presents the theory, analysis, testing and implementation of a scheme to reduce shunt compensation capacitor switching transients. The described method is switch the capacitors very near the instant when the bus voltage is at a power frequency zero. This was accomplished with a vacuum breaker on a 230 kV shunt capacitor bank.


Computer Aided Optimal Design Of Helical Gears, S. N. Muthukrishnan Jan 1980

Computer Aided Optimal Design Of Helical Gears, S. N. Muthukrishnan

Dissertations and Theses

A random search method for optimum design of a pair of helical gears has been developed. The sequence of optimization consists of two principal components. The first is the selection phase, where the output is the starting solution for the design variables - module, facewidth, helix angle and number of teeth on the pinion. The input for the selection phase includes the application environment, approximate center distance, minimum helix angle, desired values of gear ratio, pinion speed and the power to be transmitted. The limits on each of the design variables and the constraints are imposed interactively during the first …


The Design And Construction Of A Flashlamp-Pumped Frequency-Doubled Dye Laser Applicable To Long Path Monitoring Of Air Pollutants, Joel Craig Johnson Mar 1979

The Design And Construction Of A Flashlamp-Pumped Frequency-Doubled Dye Laser Applicable To Long Path Monitoring Of Air Pollutants, Joel Craig Johnson

Dissertations and Theses

The subject of this thesis is the development of a laser light source which could be used in an air pollution monitor to measure the average concentration of sulfur dioxide gas over long paths (>1 km). Many of the problems encountered in designing a long-path pollutant monitor such as instrument cost and reliability, the selection of an optimum spectral region for making the measurement, and light losses due to scattering and turbulence, are considered. The result of these considerations together with a survey of available laser light sources suggested that a frequency-doubled dye laser possessed several advantages over other …


The Development And Testing Of A Fluidic/Pneumatic Position Servo, David Lyle Portin Sep 1977

The Development And Testing Of A Fluidic/Pneumatic Position Servo, David Lyle Portin

Dissertations and Theses

This thesis reviews the design and analysis of a fluidic/pneumatic position servo. Rolling diaphragm piston actuators are used for the system drive, and a hydrostatic gas journal bearing is used as the position sensor. The servo has a 1 inch range which is monitored using an electrical capacitive position transducer that was built as an integral part of the system.

Open-loop frequency response testing provides the basis for a mathematical model of the system.

The servo response is linear at frequencies up to 3 Hertz.

The frequency response appeared to be limited by the design of the gas bearing sensor, …


The Analysis Of The Deflection And Containment Of A Hot Plume By Side Draft Exhaust Hooding, Douglas H. Macgowan May 1976

The Analysis Of The Deflection And Containment Of A Hot Plume By Side Draft Exhaust Hooding, Douglas H. Macgowan

Dissertations and Theses

A common industrial ventilation and pollution problem results when a thermally buoyant polluted plume of air must be exhausted away from a work area to allow achievement of air pollution standards. Generally, a close fitting canopy hood is one of the most effective means of exhaust containment; however, physical restrictions or the operation itself often prevent such an arrangement, and a hood located to the side of the operation is required. This arrangement requires the exhaust to bend and contain the vertically rising plume with a horizontal sweep of exhaust air across the surface of the operation.

A review of …


Computer Solution To Inverse Problems Of Elliptic Form: V²U(X,Y) = G(A,U,X,Y), Frederick Alvin Jeter Dec 1971

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 …


Direct Design Of A Portal Frame, Angel Fajardo Ugaz May 1971

Direct Design Of A Portal Frame, Angel Fajardo Ugaz

Dissertations and Theses

This investigation was undertaken to develop plastic design aids to be used in the direct design of optimum frames. It uses the concept of minimum weight of plastically designed steel frames, and the concept of linear programming to obtain general solutions. Among the special characteristics of this study are: A. The integration of both gravity and combined loading conditions into one linear programming problem. B. The application of the revised simplex method to the dual of a parametric original problem. C. The application of A and B above in the development of design aids for the optimum design of symmetrical …