Among the most famous of graduates from TU Wien are Christian Doppler (Doppler effect), Joseph Loschmidt (Loschmidt constant), architect Otto Wagner, Nobel Prizewinner for Chemistry Richard Zsigmondy, Viktor Kaplan (Kaplan turbine), Alexander Meissner (vacuum tube amplifier), computer pioneer Heinz Zemanek (first complete transistorised computer in Europe, known as “Mailüfterl”), Gottfried Ungerböck (trellis modulation) as well as composers Josef and Johann Strauß, author Fritz von Herzmanovsky-Orlando and the founder of anthroposophy, Rudolf Steiner.