Hanfried Ludloff

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Hanfried Ludloff (real name: Johann Friedrich Ludloff; in the USA then also: John Frederick Ludloff and HF Ludloff ) (born August 14, 1899 in Königsberg ; † August 9, 1987 in Los Angeles ) was a German - American physicist and university professor .

Life

Youth, military service and doctorate

Hanfried Ludloff was the only child of the orthopedist Karl Ludloff and Margarete Litten (* 1877), a sister of Fritz Litten . He spent his early childhood in Königsberg. The family later moved to Breslau , where the father had received a position as honorary professor at the local university. Ludloff attended the humanistic Johannesgymnasium in Breslau . During this time he made friends with Karl Friedrich Bonhoeffer , whose family had been with the Ludloffs since 1906. From 1914 - his father had meanwhile received a call to the newly founded University of Frankfurt am Main - he switched to the Goethe-Gymnasium in Frankfurt . After graduating from high school, Ludloff registered as a war volunteer in 1917 and served in the 2nd Nassau Field Artillery Regiment No. 63 . From June to November 1918, in his capacity as a gunner , he took part in the Battle of the Aisne and the Marne , among others . After Ludloff was discharged from the army as an ensign , he first studied mathematics and physics in Frankfurt from 1919 . He later moved to the Ludwig Maximilians University in Munich , where he was part of Arnold Sommerfeld's circle , who recommended him to Max Born in Göttingen in 1922 . In 1924 Ludloff received his doctorate from Ludwig Prandtl in Göttingen in the field of hydrodynamics on the subject of stability studies of the wave motion of a system of rotating fluid masses.

Assistant time

At Arnold Sommerfeld's instigation, Ludloff, who had a doctorate, became assistant to Adolf Kratzer in Münster in 1924 . According to Kratzers, the cooperation there proved to be fruitless and ended in 1925 with an early termination of the employment relationship by Kratzer. Ludloff then returned to Munich and worked there as a research assistant until he moved to Breslau. Ludloff himself does not mention any such turning point in his résumé. Another source writes that he was an assistant in Munich from 1924 to 1933.

From 1927 to 1933 he worked at the University of Breslau with Fritz Reiche , and from the beginning of 1928 he was part of the university's mathematics and physics department. In April 1931 he completed his habilitation in the field of theoretical physics with the title On the Question of Zero-Point Entropy of the Solid Body from the Standpoint of Quantum Statistics and thus received the right to teach at a university . To study with Werner Heisenberg , he was able to move to Leipzig from 1932 to 1933 thanks to a grant from the Notgemeinschaft der Deutschen Wissenschaft . After 1933 Ludloff became an assistant to Erwin Fues at the University of Breslau.

Exclusion

Because of his Jewish descent on his mother's side, the Nuremberg Laws passed by the National Socialists in 1935 made it impossible for Ludloff to advance further. Hanfried Ludloff contacted Hans Thirring through the surgeon Anton von Eiselsberg , who worked at the University of Vienna and a colleague of his father Karl Ludloff . He wanted to move to the University of Vienna, which turns out to be complicated, since u. a. According to Friedrich Kottler, the local offspring should be supported. He received support through letters of recommendation from Max von Laue , Erwin Fues and the work of Dean Egon Schweidler . While still working for Clemens Schaefer and Ludwig Bergmann in Breslau, he submitted his habilitation application for Austria in March 1936, together with the necessary positive report from Hans Thirring at the university there. In April 1936, the habilitation process was initially rejected by the Federal Ministry of Education due to a lack of special permits. In June 1936 a commission report was sent to the Federal Ministry, which approved the habilitation. This was followed by positive inquiries from the Federal Ministry to the University of Breslau regarding Ludloff. At the beginning of 1937 a commission from u. a. Egon Schweidler, Felix Ehrenhaft , Friedrich Kottler, Adalbert Prey and Hans Thirring recognized the habilitation thesis with the recommendation that the colloquium and the trial lecture should be waived. The subsequent vote had the result that although the colloquium was issued, a test lecture had to be held. In April 1937 the habilitation was confirmed by the Federal Ministry and, with it, the university license to teach as a lecturer in theoretical physics.

In the meantime Ludloff had been expelled from the German Physical Society as a half-Jew , to which he had been a member since 1926. Despite a recommendation from Hans Thirring issued at the end of 1937, Ludloff's efforts to take on the post of institute librarian failed when Austria was annexed in March 1938. In addition, by decree of the Austrian Ministry of Education in April 1938, the award for his habilitation thesis was withdrawn and his teaching license was withdrawn for “important reasons of public welfare”. Ludloff then turned his back on Austria in 1939 and emigrated to the USA .

Professorship in America

In 1939 Ludloff became a postdoctoral fellow with Hans Bethe at Cornell University . From 1941 he taught and researched at City College New York and from 1943 as an assistant professor of physics and aerodynamics at Princeton University . He eventually became an American citizen in September 1944. From 1954 to 1962 he was (under the name John Frederick Ludloff ) as an assistant professor of physics at the State University of New York and in 1956 was appointed professor of aeronautical engineering at New York University College of Engineering by the associate professor .

From around 1950 he carried out work for the United States Air Force (1950 to 1960: Tests for the military fleet in Maryland , 1955: Missile research program in California ). In 1962, he finished teaching at New York University and focused entirely on military research. He then worked for the Navy at the Naval Missile Center, Point Mugu, until his retirement in 1972 .

Services

At the beginning of his career, Hanfried Ludloff's scientific work was critically assessed. In 1924, Prandtl told Sommerfeld that he found Ludloff, who had just completed his doctorate, “sympathetic”, but unsuitable for an academic career. The advantages of Ludloff would be more like "scientific computing". Adolf Kratzer was not very enthusiastic about his work and complained in a letter to Sommerfeld about the lack of independence, who answered him that he Ludloff to him by the above-cited estimate of Prandtl quasi "dumped" have. In 1935, Fritz Reiche wrote in his report on Ludloff's move to the University of Vienna that he “happily combined independent thinking with thorough knowledge of the subject”. Ludloff gave his friend Karl Friedrich Bonhoeffer in 1935 when he moved to the University of Vienna as a reference for his work and person.

From 1928 Ludloff researched in the field of molecule formation and band spectra . He was able to prove connections between the shading of the bands and the exchange degeneracy of the atoms. He had found that band spectra for compounds that have an even number of electrons shade towards red (example H 2 ), whereas with an odd number they shade towards violet (example CN ), and concluded from this that the internal bond of the molecules is qualitative depends exclusively on the external electrons. This consideration is also included in the Handbook of Astrophysics, Volume III, second half, Fundamentals of Astrophysics in 1930 .

In 1931, in his habilitation, he gave an example of the directional degeneration of atoms as a result of their arrangement in the atomic lattice using defined lattice terms and term systems. He was able to prove that the high degree of degeneracy of the atoms in the lattice, which can be represented using the lattice terms, leads to thermodynamically changed entropy values. Concerning. Based on these research results, Wolfgang Pauli assumes that Ludloff worked improperly with regard to the mathematical consideration and that Hans Bethe corrected this in his work. Hans Bethe is significantly inspired by Ludloff's work and represents the starting point for the Bethe approach . However, he points to a lack of clarity in Ludloff's work due to the assumption instead of a calculation of the eigenvalues.

During the commission vote on the habilitation procedure at the University of Vienna, the following is noted as the result (two votes were actually unusual, but illustrate the problematic case):

  • Personal suitability with 22 approvals, 14 refusals and 7 abstentions
  • Scientific suitability with 22 approvals, 15 rejections and 6 abstentions

The vote for the subsequent test lecture was with 39 votes in favor, with 9 refusals and 5 abstentions considerably more positively than the previous vote. Ultimately, the habilitation was completed with distinction.

Together with his friend Fritz Reiche, Ludloff researched from 1946 until his death in 1969 in the fields of hydrodynamics and the transmission of electrical waves .

In the USA, Hanfried Ludloff studied the effects of ultrasound on matter and the aerodynamics of sound waves . He looked at z. B. the flow and reflection behavior of different surfaces in micro- and macro-structure with sound waves and described them on the basis of determined pressure and density fields. He was able to prove that the reflected shock is very weak, a slipstream exists in physical terms with a sound wave and the diffraction of the wave is influenced by differences in the shape of the impact surface. His work on this is z. B. cited in G. Ben-Dor and W. R. Sears.

His work on the aerodynamics of shock waves is especially cited with regard to the flow properties and load analysis of wings. A detailed classification of his work can be found in Srivastava.

Awards (selection)

Works (selection)

Book contribution

  • On Aerodynamics of Blasts. Advances in Applied Mechanics, Volume 3, Academic Press , 1953, pp. 109-144.

Publications

  • About a law in the shading of the band spectra. Die Naturwissenschaften , Volume 14, Issue 44, Springer, 1926, pp. 981–982.
  • On the question of the stability of the cyclone waves. Annalen der Physik , Volume 400, Issue 5, 1931, pp. 615-648.
  • On the principle question of the multiplicity of the lowest energy state. Zeitschrift für Physik , Volume 68, Issue 7/8, 1931, pp. 460–492.
  • Optical diffraction phenomena on vibrating crystals in reflected light. II. Theoretical part, session reports of the Prussian Academy of Sciences , Academy of Sciences, 1936, p. 245.
  • Ultrasonics and elasticity. The Journal of the Acoustical Society of America , 12, 1940, pp. 193-197.
  • Application of laser radar return to meteorological problems. Physics Letters A, Volume 28, No. 6, 1968, pp. 452-453.
  • Comparison of experimental and theoretical radar backscatter intensities. Physics Letters A, Volume 33, No. 3, 1970, pp. 181-182.

Co-author

  • Together with Erwin Fues: On the interpretation of the Schaefer-Bergmann interference figures on vibrating crystals. Physikalische Zeitschrift , 36, 1935, p. 214.
  • Together with Clemens Schaefer and Ludwig Bergmann: Optical diffraction phenomena on vibrating crystals in reflected light. I. Experimental part, session reports of the Prussian Academy of Sciences, Academy of Sciences, 1936, p. 245.
  • Together with Kolodner and Fritz Reiche : Corrections for drag, lift, and moment of an axially symmetrical body placed in a supersonic tunnel having a two-dimensional pressure gradient. National Advisory Committee for Aeronautics, Washington, DC, United States, 1952.
  • Together with L. Filler: Stability Analysis and Integration of the Viscous Equations of Motion. Mathematics of Computation , Vol. 15, No. 75, 1961, pp. 261-274.
  • Together with RW Claassen: Diffusion of contamination from a source of finite extent. Journal of Applied Physics 37, 1966, p. 447.

Military reports

  • Together with DF de Santo: Attempts at derivation of transition from laminar into turbulent flow along a flat plate. Air Force Office of Scientific Research, United States Air Force , 1960.
  • Three-dimensional, analytical solutions to the problems of diffusion of wind-driven contamination. Technical Memorandum No. PMR-TM-66-4, Point Mugu, Pacific Missile Range, 1966.

literature

  • Rudolf Friedrich Ludloff : History of the Ludolf-Ludloff family. Roßteutscher, 1910, pp. 70-71.
  • Daniela Claudia Angetter, Michael Martischnig: Biographies of Austrian (physicists) women. A selection. Austrian State Archives , 2005, p. 85.
  • Nobert Schmitz: Adolf Kratzer 1893–1983. Scientific writings of the WWU Münster, 2011, p. 49 ff.

Web links

Individual evidence

  1. ^ J. Zutt, E. Straus, E. Scheller: Karl Bonhoeffer: For the hundredth birthday on March 31, 1968 . Springer-Verlag, 2013, ISBN 978-3-642-49941-8 , pp. 75 ( Google Books [accessed January 5, 2018]).
  2. ↑ a b c Hanfried Ludloff: curriculum vitae. 1935, p. 1 , accessed February 18, 2018 .
  3. ^ A b Nobert Schmidt: Adolf Kratzer 1893–1983. (No longer available online.) 2011, p. 49 ff. , Archived from the original on February 19, 2018 ; accessed on February 18, 2018 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / core.ac.uk
  4. ↑ a b c d e f g h Walter Höflechner: Materials for the development of physics and its "peripheral subjects" astronomy and meteorology at the Austrian universities 1752-1938. Part 2: Biographies. In: uni-graz.at. P. 179 , accessed on February 22, 2018 .
  5. ↑ a b c Hanfried Ludloff: curriculum vitae. 1935, p. 2 , accessed February 18, 2018 .
  6. ↑ Wolfgang L. Reiter: Departure and Destruction. On the history of natural sciences in Austria from 1850 to 1950 . Ed .: Friedrich Stadler. LIT Verlag Münster, 2017, ISBN 978-3-643-50825-6 , p. 37 ( Google Books [accessed February 18, 2018]).
  7. ^ Norbert Schmidt: Adolf Kratzer 1893–1983. (No longer available online.) 2011, p. 50 , archived from the original on February 19, 2018 ; accessed on February 22, 2018 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / core.ac.uk
  8. ^ Letter from Max v. Laue and Ernst Fuest to Hans Thirring (Berlin, August 13, 1935). Retrieved January 5, 2018 .
  9. ↑ Thirring, Hans: Expert opinion on the habilitation application from Dr. Hanfried Ludloff. Retrieved January 5, 2018 .
  10. ↑ Commission report on Dr. Johann Friedrich Ludloff (Theoretical Physics). 1937, Retrieved February 18, 2018 .
  11. ↑ a b c d e f Walter Höflechner: Materials for the development of physics and its "peripheral subjects" astronomy and meteorology at the Austrian universities 1752-1938. Part 2: Biographies. In: uni-graz.at. P. 180 , accessed on February 22, 2018 .
  12. ^ Letter from Ludloff, Hanfried to the Federal Chancellery in Vienna, Migration Office Department (Vienna, 1937-12-07). Retrieved January 5, 2018 .
  13. ^ Austria-Forum: Austrian Central Library for Physics - Beginnings of a joint establishment of a joint institute library in 1920 . In: Austria Forum . ( Online [accessed January 5, 2018]).
  14. ↑ a b c d Walter Höflechner: Materials for the development of physics and its "peripheral subjects" astronomy and meteorology at the Austrian universities 1752-1938. Part 2: Biographies. In: uni-graz.at. P. 181 , accessed February 22, 2018 .
  15. ↑ Friedrich Stadler (Ed.): Displaced Reason II. Emigration and Exile of Austrian Science 1930–1940 . LIT Verlag Münster, 1987, ISBN 978-3-8258-7373-8 , pp. 709 ( Google Books [accessed January 6, 2018]).
  16. ↑ Wolfgang L. Reiter: Awakening and Destruction: On the History of Natural Sciences in Austria 1850 to 1950 . LIT Verlag Münster, 2017, ISBN 978-3-643-50825-6 , p. 220 ( Google Books [accessed February 18, 2018]).
  17. ^ Dieter Hoffmann, Mark Walker: The German Physical Society in the Third Reich: Physicists between Autonomy and Accommodation . Cambridge University Press, 2012, ISBN 978-1-107-00684-3 , pp. 426 ( Google Books [accessed January 5, 2018]).
  18. ^ Silvan S. Schweber, SS Schweber: Nuclear Forces: The Making of the Physicist Hans Bethe . Harvard University Press, 2012, ISBN 978-0-674-06553-6 , pp. 314 ( Google Books [accessed January 5, 2018]).
  19. ↑ Wolfgang L. Reiter: Awakening and Destruction: On the History of Natural Sciences in Austria 1850 to 1950 . LIT Verlag Münster, 2017, ISBN 978-3-643-50825-6 , p. 263 ( Google Books [accessed January 5, 2018]).
  20. ^ Aeronautical Engineering Review . Institute of the Aeronautical Sciences, July 1956, pp. 178 ( Google Book [accessed January 5, 2018]).
  21. ^ Friedrich Stadler: Displaced reason: Emigration and exile of Austrian science . LIT Verlag Münster, 1987, ISBN 978-3-8258-7373-8 , pp. 668 ( Google Books [accessed February 18, 2018]).
  22. ^ Opinion by Fritz Reiche for Ludloff's transfer to the University of Vienna. 1935, p. 4 , accessed February 18, 2018 .
  23. ^ Wolfgang Pauli: Scientific correspondence with Bohr, Einstein, Heisenberg et al. Volume II: 1930-1939 / Scientific Correspondence with Bohr, Einstein, Heisenberg ao Volume II: 1930-1939 . Springer-Verlag, 2008, ISBN 978-3-540-78801-0 , p. 94 ( Google Books [accessed January 5, 2018]).
  24. ^ Silvan S. Schweber, SS Schweber: Nuclear Forces: The Making of the Physicist Hans Bethe . Harvard University Press, 2012, ISBN 978-0-674-06553-6 , pp. 200 ( Google Books [accessed February 18, 2018]).
  25. ↑ Benjamin Bederson: Fritz Reiche and the Emergency Committee in Aid of Displaced Foreign Scholars. (No longer available online.) In: Phys. perspective. 7. 2005, pp. 461 + 470 , archived from the original on November 27, 2009 ; accessed on February 19, 2018 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / bederson.org
  26. ↑ Gabi Ben-Dor: Shock Wave Reflection Phenomena . Springer Science & Business Media, 1992, ISBN 978-1-4757-4279-4 , pp. 286 ( Google Books [accessed February 15, 2018]).
  27. ^ William Rees Sears: Small Perturbation Theory . Princeton University Press, 2015, ISBN 978-1-4008-7902-1 , pp. 63 ( Google Books [accessed February 15, 2018]).
  28. ↑ LG Gvozdeva, SA Gavrenkov: Formation of triple shock configurations with negative reflection angle in steady flows . In: Technical Physics Letters . tape 38 , no. 4 , April 1, 2012, ISSN  1063-7850 , p. 372-374 , doi : 10.1134 / S1063785012040232 .
  29. ^ Howard W. Emmons: Fundamentals of Gas Dynamics . Princeton University Press, 2015, ISBN 978-1-4008-7753-9 , pp. 522 ff . ( Google Books [accessed February 15, 2018]).
  30. ^ RS Srivastava: Interaction of Shock Waves . Springer Science & Business Media, 2012, ISBN 978-94-011-1086-0 ( Google Books [accessed February 15, 2018]).
  31. ^ Corrections for drag, lift, and moment of an axially symmetrical body placed in a supersonic tunnel having a two-dimensional pressure gradient. Retrieved January 5, 2018 .

Remarks

  1. ↑ The date and place of death are incorrectly stated in some sources as "1965, Vienna". Ludloff died in America, which is clearly proven by his death certificate with the correct date and place of birth and the correct details of the parents.
personal data
SURNAME Ludloff, Hanfried
ALTERNATIVE NAMES Ludloff, Johann Friedrich (full name)
BRIEF DESCRIPTION German-American physicist and university professor
DATE OF BIRTH August 14, 1899
PLACE OF BIRTH Koenigsberg
DATE OF DEATH August 9, 1987
Place of death los Angeles