Affiliation: | a Fakultät für Mathematik, Ruhr-Universität Bochum, Universitätsstraβe 150, 44780 Bochum, Germany b Department of Chemical and Process Engineering, University of Sheffeld, Mappin, Street, Sheffeld, S1 3JD, UK c Department of Physics and Technology, The University of Bergen, Allegaten 55, 5007 Bergen, Norway |