At the 14th of June 2013 the 9th Arnold Tross Colloquium was held at our university. More than 35 participants from several sectors of industry and universities visited the colloquium. A lively debate took place between the presentation and after the official part.As always the conference presents investigations of fundamental questions and applications in machine elements. A pleasurable atmosphere supported the exchange of ideas and enabled a discussion about new and surprising viewpoints.It was the second time that we welcomed researchers from University of Porto. A very intensively discussed paper came from University of Stuttgart. Dr. Bauer presented his work about Tribology of seals and delivered very interesting results.