Parametric study of corn cob biochar (CCBc) yield via microwave pyrolysis Kristine Iannah Lawas, Stephen Doliente, Rowena Carpio, Veronica Migo and Catalino Alfafara MATEC Web Conf., 268 (2019) 04005 Published online: 20 February 2019 DOI: 10.1051/matecconf/201926804005