1. Department of Mechanical and Materials Engineering Faculty of Technology University of Turku Turku FI-20014 Finland
2. Department of Applied Physics School of Science Aalto University Espoo FI-00076 Finland
3. Department of Bioproducts and Biosystems School of Chemical Engineering Aalto University Espoo FI-00076 Finland
4. Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA