1. Department of Chemical EngineeringUniversity of Patras & FORTH‐ICE/HT Patras GR 26504 Greece
2. Institute of Materials ScienceUniversity of Stuttgart Heisenbergstr. 3 Stuttgart 70569 Germany
3. Department of Mechanical and Process EngineeringParticle Technology LaboratoryETH Zürich Sonneggstrasse 3, ML F 14.2 Zürich CH‐8092 Switzerland