1. CEMAT and Department of Mathematics, Instituto Superior Técnico (TULisbon), Lisbon, Portugal
2. Department of Mechanical Engineering, Military Institute of Engineering, Rio de Janeiro, RJ, Brazil
3. ICIST and Department of Civil Engineering and Archit., Instituto Superior Técnico (TULisbon), Lisboa, Portugal
4. CEMAT-IST and Department of Mathematics, Fac. Ciências e Tecnologia (UNLisbon), Quinta da Torre, Caparica, Portugal
5. Department of Mechanical Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
6. Program of Nuclear Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil