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Full-Text Articles in Physics

Study Of Beamforming Techniques For Ultrasound Imaging In Nondestructive Testing , Sleiman Riad Ghorayeb Jan 1992

Study Of Beamforming Techniques For Ultrasound Imaging In Nondestructive Testing , Sleiman Riad Ghorayeb

Retrospective Theses and Dissertations

Many of the innovations in modern materials testing technology make use of ultrasound. Therefore, the theory and application of ultrasound have become of extreme importance in nondestructive inspection of complete engineered systems. However, despite the fact that most of these ultrasound inspection techniques are based on well-established phenomena, two key problems pertaining to their application still remain unresolved. These problems can be identified as (1) the material being tested is assumed to be isotropic and homogeneous by nature, and (2) the scanning/data collection process, prior to the reconstruction scheme, is very time consuming. As a result, techniques for fast ...


Characteristics And Applications Of The Short External Cavity Laser Diode , Jin-Yong Kim Jan 1992

Characteristics And Applications Of The Short External Cavity Laser Diode , Jin-Yong Kim

Retrospective Theses and Dissertations

The characteristics of the external cavity laser diode are investigated. Emphasis is placed on the short external cavity configuration. The general governing model equations which include the multiple reflection effect are derived. It is shown that the coupling coefficient becomes a complex function of the external cavity length and the near field beam size of the laser diode due to the diffraction loss of an open resonator. The validity of this open resonator model is proven experimentally by the asymmetry in optical power versus external cavity length characteristic curve. For analysis of the ultra short external cavity laser, it is ...


Theory Of Eddy Current Inspection Of Layered Metals , Erol Uzal Jan 1992

Theory Of Eddy Current Inspection Of Layered Metals , Erol Uzal

Retrospective Theses and Dissertations

Some forward and inverse problems related to layer sizing in eddy current nondestructive evaluation (NDE) were examined and experimental tests were done. An air-core or ferrite-core eddy current probe coil above a half space is considered. The half space's conductivity changes only as a function of depth, but otherwise it is arbitrary. A numerical method for the computation of coil impedance based on the exact solution of Cheng, Dodd and Deeds (International Jour. of Nondestructive Testing, 3, 109-130,1971) is described. Also, for a specific conductivity profile involving the hyperbolic tangent function, the exact solution for the impedance is ...


A Comparison And Evaluation Of The Effectiveness Of Computer Simulated Laboratory Instruction Versus Traditional Laboratory Instruction In Solid State Electronics Circuitry , Mahmoud Arshadi Nejad Jan 1992

A Comparison And Evaluation Of The Effectiveness Of Computer Simulated Laboratory Instruction Versus Traditional Laboratory Instruction In Solid State Electronics Circuitry , Mahmoud Arshadi Nejad

Retrospective Theses and Dissertations

This study was designed to compare and evaluate the effectiveness of computer simulated laboratory instruction versus traditional laboratory instruction (utilizing actual electronics components) for educating college students about solid state electronics circuitry. The study also examined the students' attitude toward computer simulated laboratory instruction versus traditional laboratory instruction as a means of conducting laboratory activities;A pretest-posttest control group design was used in this experiment. In this study, the researcher randomly assigned subjects to particular groups. The experimental group received the pretests, experimental treatment, posttest I, traditional treatment, posttest II, and the posttests, while the control group received the pretests ...