1. Centre for Micro-Electro Mechanical Systems (MEMS), University of Minho, Guimarães, Portugal
2. MAHLE - Componentes de Motores S.A., Núcleo Industrial Murtede, Cantanhede, Portugal
3. GRF-CFUM, Department of Physics, University of Minho, Guimarães, Portugal
4. Mechanical Engineering Department, Universidade do Minho, Guimarães, Portugal