Acknowledgements

This thesis would not have been completed without the help, inspiration and advise of many indi-viduals. Some of the names I might forget to mention here but each one of them have played a role in fulfillment of this work. First and foremost, I am forever indebted to Dr. Kirti Chandra Sahu, my advisor, and Dr. Harish Dixit, my co-advisor for motivating and guiding me along this memorable journey. They remains and will remain, first source of advice and a constant source of inspiration, both in research and in life. They are the fist ones in my life who taught me the alphabets of research.The numerous discussions I had with them in their offices are the priceless lectures for which I will remain ever grateful to them. I am very much thankful to our Director, Prof. U. B. Desai, for providing us with an environment to carry out our research without any hurdles. I would like to express my sincere gratitude to our Head of the Department, Dr. Vinod Janarthanan, who support us in every possible way for the completion of this project. I am very much grateful to all the members of my committee, Dr. Raja Banerjee and Dr.venkatsubhaiya, for their invaluable suggestion which helped me enormously during this work. I would like to thank all the faculty members of Department of Chemical Engineering, IIT Hyder