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An Experimental Investigation Of The Hole-Drilling Technique For Measuring Residual Stresses In Welded Fabricated Steel Tubes, Chau Mong Tran

Dissertations and Theses

Among semi-destructive methods of measuring residual stresses in elastic materials, the blind hole-drilling strain-gage method is one of the best because it is simple, economical and accurate. It is based on the measurement of strains disturbed by machining a small diameter shallow hole in the test piece. The strains measured in three known directions permit the determination of the direction and magnitude of principal stresses and subsequently of any stress in any direction.

This thesis presents the investigation of residual stresses in the longitudinal direction of a welded fabricated steel tube of 22 inch diameter, relating to a series of …

Light Extinction In Polydisperse Particulate Systems, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Analytic methods are developed for determining the attenuation characteristics of light beams propagating through ensembles of scattering particles including those with complex index of refraction. The methods are applicable to a wide range of practical particulate systems, and the results are expressed explicitly in terms of elementary functions. Propagation through fog and clouds is considered as an example, and it is found that absorption by the liquid lengths. water in such ensembles affects strongly the extinction for ir wave-lengths

Assessment Of Feasibility Of Proposed Bolted Connections For Tubular Structures, John Henry Tausch

Dissertations and Theses

The search for new and additional sources of energy -- from sun, wind, waves, and ocean currents -- is necessitating the development of structures in the open environment of the oceans as well as on land. The advantages of round or tubular members for use in such structures are shown; and to avoid the uncertainties of welded joints, two bolted connections are proposed and their feasibility explored.

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, …

Error Codes In Digital Data Communication Systems, Robert Hadley Cravens

Dissertations and Theses

Today’s digital communication systems perform data transfers at the rate of millions of bits per minute, with data errors in the order of 1/6th error per day. This magnitude of errorless communication is now possible because of sophisticated error correcting codes. Many types of error codes are employed today in three distinct areas of digital data communication: human to computer; data source to computer; computer to computer; and intra-computer; we are concerned here with intra-computer communication.

This research is primarily a mathematical study of error codes in general to explore the possibilities of each major type for the purpose of …

Limit Design Of Unbraced Reinforced Concrete Frames, Thomas Joseph Gavin

Dissertations and Theses

The main objective of this study was to determine whether Limit Design could be applied to low-rise unbraced concrete frames. The investigation was carried out both analytically and experimentally.

In the analytical part, two mathematical models were used to determine the behavior of unbraced frames. The first method used a nonlinear computer program, which takes into account the material and geometric nonlinearities of concrete frames. Several cases of frames with different reinforcement ratios and under different beam to column load ratios were investigated. For each frame the gravity loads were increased proportionately to 3/4 of the ultimate frame capacity. Then, …

An Experimental Investigation Of Unbraced Reinforced Concrete Frames, Nourollah Samiee Nejad

Dissertations and Theses

The main objective of this investigation is to study experimentally the behavior of rectangular reinforced concrete frames subject to a combination of low column loads, beam loads, and lateral load. The analytical tool used in this investigation is a computer program which is a generalized computational method for non linear force deformation relationship and secondary forces due to displacement of the joints during loading.

In the experimental portion of this investigation, two rectangular frames, one design by the Ultimate Strength Design method and the other by a Limit Design method were prepared and tested to failure with short time loading. …

Single Particle Scattering With Focused Laser Beams, Lee W. Casperson, Cavour W. Yeh

Electrical and Computer Engineering Faculty Publications and Presentations

A scattering technique is described in which the incident laser beam is tightly focused to isolate the effects of a single particle. In this way the individual particles may be studied in their natural environment, and experiments with latex spheres are in agreement with the theory.

Threshold Characteristics Of Mirrorless Lasers, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Detailed analytical expressions are developed for the output power and spectral characteristics of high‐gain mirrorless laser amplifiers. With regard to intensity variations and spectral narrowing, such lasers are similar in behavior to conventional laser oscillators. A threshold transition region is apparent as saturation sets in, and spectral rebroadening occurs in inhomogeneously broadened laser systems. These solutions take full account of saturation by both the right and left propagating radiation, and the results agree with experiments that have been reported.