1. Department of Mechanical Engineering; Materials Technology Institute, Eindhoven University of Technology; P.O. Box 513 Eindhoven MB 5600 the Netherlands
2. Department of Chemistry and Industrial Chemistry; University of Genova; Via Dodecaneso 31 Genova Italy
3. Faculty of Engineering Technology; University of Twente; P.O. Box 217 Enschede AE 7500 the Netherlands