Professor Kees Rietema died at the age of almost 72; the Dutch scientific community thus lost a remarkable character. Kees Rietema may be described as a scientist through and through, and one of the pioneers of physical technology-which he himself preferred to call process science. Rietema studied physics at the Groningen State University and took his doctorate under Professor Heertjes at the Technical University of Delft in 1952. After joining Shell, he carried out some ground-breaking work on the hydrodynamics of cyclones. He rapidly .rose to prominence, partly through his work at Shell, and partly through his involvement in the burgeoning activities of the European Federation of Chemical Engineering (the first symposium on Chemical Reaction Engineering was held in Amsterdam in 1957). Not surprisingly, therefore, he was appointed as the newly established Technical University of Eindhoven's first lecturer in physical technology in June 1959.
The following year, his new laboratories ready, Kees Rietema began teaching. For his students, his lectures were an eye-opening experience. He always asserted that his discipline was essentially very simple and that all you really needed was plenty of common sense even if in practice things seem different. He instilled in his students the idea that they had to learn to think independently about elementary physical mechanisms, quite an experience once the collection of data and information was complete.