Dr. Radoslav Paulen and PhD candidate Martin Mojto conducted a research exchange stay at Technische Universität Dortmund, Germany from August, 31 to September, 11. During the stay, Dr. Paulen gave a seminar on "Optimal Control of Batch Membrane Processes" a Mr. Mojto presented his research work in the lecture "Control structure analysis and design of inferentials for an industrial depropanizer column".