Ultrasonic flaw classification and sizing

Flaw classification (determination of the flaw type) and flaw sizing (prediction of the flaw shape, orientation and sizing parameters) are very important issues in ultrasonic nondestructive evaluation of materials. In this work, new techniques for both classification and sizing are described;In the area of flaw classification, a methodology is developed which can solve classification problems in weldments using probabilistic neural networks. In the area of flaw sizing, four new approaches are presented including (1) the determination of distance-gain-size (DGS) curves and frequency response curves for flat-bottom holes based on a theoretical ultrasonic scattering model, (2) a time-of-flight equivalent (TOFE) sizing method for relatively large (\u3e1 mm) flaws in materials, (3) an amplitude-based equivalent (ABE) sizing method and (4) a first moment (FM) sizing method. Both the third and fourth methods are shown to be new viable techniques for sizing relatively small (\u3c1 mm) flaws in materials

Comparison of Transition Matrices Between Metropolitan and Non-Metropolitan Areas in the State of Utah Using Juvenile Court Data

The purpose of this paper is to use Markov Chains for the study of youths referred to the juvenile court in the metropolitan and non-metropolitan areas of the state of Utah. Two computer programs were written for creating case histories for each person referred to the court and for testing for the significance of the difference among several transition matrices. Another computer program, which was written by Soo Hong Uh, was used for analyzing realizations of a Markov chains up to the 4th order; a third computer program, originally written by David White, was used for interpreting Markov chains. The paper is divided into SIX chapters: introduction and thesis goals, definition of SMSA (Standard Metropolitan Statistical Area), statistical background, methodology, analysis and summary and conclusions