sentences:  From 1921, he was an ordinarius professor at the Danzig "Technische Hochschule".From 1928 to 1945 he was director of the research division of the "Allgemeine Elektrizitäts-Gesellschaft" (AEG), an electric combine with headquarters in Berlin and Frankfurt am Main.During the period 1931 to 1945, in addition to his position at AEG, he was honorary professor at the Berlin "Technische Hochschule"; the title meant that he was authorized to teach at the facility, but not required.