1. Department of Mechanical Engineering, Faculty of Engineering, Universitas Muhammadiyah Surakarta, Jl. A. Yani Tromol Pos 1 Pabelan Kartasura, Surakarta 57102, Indonesia
2. Akademi Maritim Nusantara Cilacap, Jl. Kendeng 307 Sidanegara, Cilacap 53223, Indonesia