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 - Influence of the number of blade in hydro microturbine due to flow velocity