Integrating biomass gasification with solid oxide fuel cells: Effect of real product gas tars, fluctuations and particulates on Ni-GDC anode - Hofmann, Ph; Panopoulos, Kyriakos D.; Fryda, Lydia Emilie; Schweiger, A; Ouweltjes, Jan Pieter; Karl, Jürgen (International Journal of Hydrogen Energy, 2008)