1. Department of Mechanics, Mathematics and Management, Politecnico di Bari, Bari, Italy
2. Department of Mechanical Engineering, Faculty of Engineering, Uludag University, Bursa, Turkey
3. Physics Department M Merlin, Institute for Photonics and Nanotechnologies (Consiglio Nazionale delle Ricerche), Bari, Italy
4. Department of Mechanical Engineering, Imperial College London, London, UK