1. Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna, Italy
2. Department of Chemical and Process Engineering, University of Canterbury, Private Bag 4800, 8140 Christchurch, New Zealand. Current address: Institute for Bio Engineering, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FB, United Kingdom