A process for converting a biomass material comprising a) converting a biomass material in one or more steps into one or more C3-C12 oxygenates; b) contacting the one or more C3-C12 oxygenates with hydrogen at a hydrogen partial pressure of more than 1. First, a polysilicon layer is formed to fill a contact hole between two adjacent insulating structures and cover the entire surface of a semiconductor substrate to a predetermined height, in which a sunken portion is formed in the polysilicon layer over the contact hole. The impact device comprises a working chamber and means for conveying pressure fluid as pressure pulses thereto such that a force is produced between the frame of the impact device and a tool to press the tool towards the material to be processed. The paired igniter pins are encased in alumina ceramic, a high dielectrichigh temperature housing positioned around the combustion chamber holding and insulating the electrodes relative to their position in reference to the combustion chamber.