Toshio Hattori is Professor Emeritus of Gifu University. He obtained a Ph.D. from the Tokyo Institute of Technology. Hattori is a Fellow of the Japan Society of Mechanical Engineers and has received awards for his achievements in the Strength of Materials Division and the Mechanical Materials & Processing Division. His research focuses on strength and reliability design technology for rotating electrical machinery, including turbine generators and gas turbines. Hattori has contributed to education and research in material mechanics, plastic mechanics, industrial material science, plastology, industrial English, and thesis guidance. He is currently providing technical consultation and lectures to manufacturing companies and writing technical books.

Tomohiro Naruse is a Professional Engineer (Mechanical) in Japan. He received his bachelor's, master's, and Ph.D. in mechanical engineering from Osaka University. Naruse has received the Japan Society of Mechanical Engineers Medal for New Technology and the High Pressure Institute of Japan Promotion Award for Science and Technology. He specializes in strength and reliability technology for products and equipment, and has been involved in research at the Mechanical Engineering Research Laboratory at Hitachi, Ltd. Naruse also participates in the research committee of the Japan Research Institute for Screw Threads and Fasteners.