1. “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
2. Department of Biological and Agricultural Engineering, Louisiana State University Agricultural Center, 149 E. B. Doran, Baton Rouge, LA 70803-4505, USA
3. Department of Energy Production and Use, University Politehnica of Bucharest, 313 Splaiul Independentei, 060042 Bucharest, Romania