1. Max-Planck-Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, D-39106 Magdeburg, Germany, Institut für Automatisierungstechnik, Otto-von-Guericke Universität, D-39106 Magdeburg, Germany, and Department of Chemical Engineering, Indian Institute of TechnologyBombay, Powai, 400076 Mumbai, India