1 Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-von-Liebig-Weg6, 18059 Rostock, Germany; Deutsches Biomasseforschungszentrum gGmbH, the German Centre for Biomass Research, Torgauer Straße 116, 04347 Leipzig, Germany. Electronic address: michael.nelles@uni-rostock.de.
2 ICEA, Department of Civil, Environmental and Architectural Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy. Electronic address: alberto.pivato@unipd.it.