Cândida Vilarinho, Department of Mechanical Engineering at the University of Minho, Guimarães, Portugal. Fernando Castro, Department of Mechanical Engineering at the University of Minho, Guimarães, Portugal. Margarida Goncalves, Faculty of Science and Technology, New University of Lisbon, Caparica, Portugal. Ana Luisa Fernando, Faculty of Science and Technology, New University of Lisbon, Caparica, Portugal.