**Author details**

Ancuta M. Magurean, Octavian G. Pop, Adrian G. Pocola, Alexandru Serban and Mugur C. Balan\* Technical University of Cluj-Napoca, Cluj-Napoca, Romania

\*Address all correspondence to: mugur.balan@termo.utcluj.ro

© 2019 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.
