r---This work could not have been started, completed, or anything else without the help of my advisor! R.S. Michalski. Professors Robert E. Stepp and Arthur Baskin were also supportive, if not helpful, understanding, patient and downright nice guys. My fellow graduate students have always been an inspiration, particularly Carl Uhrik, and Stephen Borodkin, who not only gave useful advice but also were real regular nice guys. Also worth mentioning are Wayne Woodmansee and Bill Motzer of Boeing for supplying ultrasound images, who, although I didn't get to know too well, did seem like reasonably nice guys. And then there are all those whose contributions simply transcend the nice guy label: Richie, Maharishi, Gabriel, Michael and his eternal partner, D-E-F the second, Brother (in