Add to ORKGii ACKNOWLEDGMENTS I wish to express my gratitude to my advisor Prof. S. Nandi and to my collab-orator and friend Dr. C. Macesanu for all the guidance, encouragement and patience shown while I was a Ph.D. student. I would also like to extend my gratitude to my other committee members Prof. K. S. Babu, Prof. J. Mintmire, Prof. J. Chandler and Prof. B. Binegar, to the rest of the the members of the High Energy Physics group, to the Physics Department. I want to thank also to the US Department of Energy for providing part of my financial support. And last but by no means the least, many, many thanks to my family and friends from home for their support when I needed it the most. iii i