sentences:  In 1929 she earned her doctorate in engineering, publishing her thesis on the mathematical theory of circular cylinders and heat conduction.Lotz went to work for the Aerodynamische Versuchsanstalt (AVA) in Göttingen, one of the most prominent aeronautical research institutions in Europe.She joined as a junior research engineer and worked closely with Ludwig Prandtl and Albert Betz, two of the leading German aerodynamicists of the time.