1. Department of Chemical Engineering; Jeju National University; Jeju 690-756 Korea
2. Department of Mathematics; Indian Institute of Technology Roorkee; Roorkee India
3. Institute of Computer Applications; Manglayatan University; Aligarh India
4. Department of Chemical Engineering; University of Texas; Austin TX 78713 USA
5. School of Mechanical Engineering; Yonsei University; Seoul 120-749 South Korea