a
Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, USA
E-mail: hnulwala@andrew.cmu.edu
;
Fax: +1-412 929-8102
;
Tel: +1-412 268-5927
b
National Energy Technology Laboratory, United States Department of Energy, P. O. Box 10940, Pittsburgh, USA
c
Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, USA