SEMDOK 2018 : 23rd international seminar of Ph.D. students under the auspices of prof. Dr. Ing. Milan Sága Dean of the Faculty of Mechanical Engineering of the University of Žilina : Western Tatras - Zuberec, Slovakia : January 24-26, 2018. (University of Žilina, Faculty of Mechanical Engineering, Department of Materials Engineering, 2018)