**Author details**

Florica Manea<sup>1</sup> \* and Corina Orha<sup>2</sup>

\*Address all correspondence to: florica.manea@upt.ro

1 Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University of Timisoara, Timisoara, Romania

2 Condensed Matter Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Romania
