1. School of Mechanical Engineering and Safety Engineering, University of Wuppertal, Wuppertal, Germany;
2. Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich, Germany;
3. School of Architecture and Civil Engineering, University of Wuppertal, Wuppertal, Germany;
4. Institute for Theoretical Physics, University of Cologne, Cologne, Germany