1. Bulgarian Academy of Sciences; Institute of Chemical Engineering; Akad. G. Bonchev Str., bl. 103 1113 Sofia Bulgaria
2. European Polytechnic University; Pernik St. St. Kiril i Metodiy Str., 23 2300 Pernik Bulgaria
3. Technical University of Darmstadt, Department of Mechanical Engineering; Institute of Structural Mechanics; Franziska-Braun Str. 7 64287 Darmstadt Germany