1. MEtRICs, University of Minho Guimarães,Mechanical Engineering Department,Portugal
2. Instituto Superior de Eng. do Porto (ISEP), Portugal CMEMS-UMinho, Minho Univ.,Physics Dep.,Portugal
3. University of Strathclyde,Department of Mechanical and Aerospace Engineering,Glasgow,UK
4. MEtRICs, Univ. of Minho,Mechanical Engineering Dep.,Guimarães,Portugal
5. Center for MicroElectromechanical Systems (CMEMS-UMinho), University of Minho,Guimarães,Portugal