by

First of all I would like to express my heartfelt and deepest appreciation to my advisor and major professor Dr. Ernest A. Mendrela for his invaluable suggestions and constant guidance. I also thank Dr. Hsiao-Chun Wu and Dr. Ashok Srivastava for sparing their time to be a part of my defense committee. I would also thank Dr. Hallie Dozier and Dr. Chunyan Li, for supporting me through out my stay here at LSU. I would like to express my gratitude towards my family members for their suppor