1. Department of Chemical Engineering, Rice University, Houston, Texas 77251
2. Syncrude Canada, Ltd., Edmonton Research Centre, 9421 17th Avenue, Edmonton, Alberta T6N 1H4, Canada
3. Institut Français du Petrole (IFP), 1 & 4, Avenue de Bois-Préau, 92852 Rueil−Malmaison Cedex, France