I would like to thank, Prof. Ricardo Luís Doretto, for the orientation, patience and all needed support to the realization of this thesis;Unicamp and IFGW for the welcoming and supporting environment for the students; the university structure that makes my work not only possible but extremely comfortable; all IFGW staff, specially for CPG and DFMC for the excellent support; CNPq for the given opportunity of this Ph.D. scholarship; my wife Ingrid for all her support and inspiration; and to my family and friends, near and distant, who have always supported me in my journey.