This work was sponsored by the U.S. Air Force Office of Scientific Research under Contract F49620-82-K-0021;
and was submitted by the first author as partial fulfillment of the requirements for the degree of Doctor of Philosophy. The technical assistance of T. Lovelace;
F;
Galimba;
G;
Cartwright;
W;
Heckman;
and B. Bain is gratefully acknowledged;