**Author details**

Nicolae Vasiliu\*, Daniela Vasiliu, Constantin Drăgoi, Constantin Călinoiu and Toma Cojocaru-Greblea University POLITEHNICA of Bucharest, Bucharest, Romania

\*Address all correspondence to: nicolae.vasiliu@upb.ro

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
