AIP Conference Proceedings [AIP Publishing EXPLORING RESOURCES, PROCESS AND DESIGN FOR SUSTAINABLE URBAN DEVELOPMENT: Proceedings of the 5th International Conference on Engineering, Technology, and Industrial Application (ICETIA) 2018 - Surakarta, Indonesia (12–13 December 2018)] EXPLORING RESOURCES, PROCESS AND DESIGN FOR SUSTAINABLE URBAN DEVELOPMENT: Proceedings of the 5th International Conference on Engineering, Technology, and Industrial Application (ICETIA) 2018 - The effect of 5% ethanol in 88, 92, and 98 RON gasoline on motorcycle engine performance