1. Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-97187 Luleå, Sweden
2. Microelectronics Research Group, University of Oulu, FI-90570 Oulu, Finland
3. Fibre and Particle Engineering Research Group, University of Oulu, FI-90570 Oulu, Finland
4. Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, ON M5S 3G8, Canada