1. Department of Earth & Environmental Engineering, Henry Krumb School of Mines, Columbia University, New York, NY 10027. Phone: 212-854-6390; E-mail: mc2352@columbia.edu
2. Department of Earth & Environmental Engineering, Henry Krumb School of Mines, Columbia University, New York, NY 10027
3. Department of Chemical Enigeering, University of California, Berkeley, Berkeley, CA 94720-1462