Ayhan Demirbas is a full professor and Vice Rector at Sirnak University. He was Professor in Energy Technologies Science at Karadeniz Technical University between 1991 and 2001, at Selcuk University from 2003 to 2007, and at Sila Science and Energy from 2007 to 2009. His research is mainly concerned with renewable and sustainable energy.M. Fatih Demirbas became Associate Researcher at Sila Science and Energy in 2003 and is now a full professor with the same company. His research focuses on renewable energy sources, notable solar energy and biomass energy technologies (biodiesel; biofuels; biomass pyrolysis; liquefaction and gasification; and biohydrogen).