John W. Cahn, German-American metallurgist and academic (b. 1928)
John Werner Cahn (January 9, 1928 – March 14, 2016) was an American scientist and recipient of the 1998 National Medal of Science. Born in Cologne, Weimar Germany, he was a professor in the department of metallurgy at the Massachusetts Institute of Technology (MIT) from 1964 to 1978. From 1977, he held a position at the National Institute of Standards and Technology (formerly the National Bureau of Standards). Cahn had a profound influence on the course of materials research during his career. One of the foremost authorities on thermodynamics, Cahn applied the basic laws of thermodynamics to describe and predict a wide range of physical phenomena.