Gross calorific values
the gross heating values were measured by an oxygen bombcalorimeter (model AC-350, LECO Corporation, USA) according toASTM D 240 [33]. A crucible was used to place the biofuels insidethe calorimeter to test the heating value and to collect carbonresidual after burning the tested fuel. The heat of combustionwas calculated by the measured temperature increase of the waterbath surrounding the bomb