1. K. P. Johnston and K. L. Harrison, Department of Chemical Engineering, University of Texas, Austin, TX 78712, USA.
2. M. J. Clarke and S. M. Howdle, Department of Chemistry, University of Nottingham, Nottingham NG72RD, UK.
3. M. P. Heitz and F. V. Bright, Department of Chemistry, State University of New York, Buffalo, NY 14250, USA.
4. C. Carlier and T. W. Randolph, Chemical Engineering Department, University of Colorado, Boulder, CO 80309, USA.