2.670 professor Douglas P. Hart adjusts Alison S. Greenlee's '09 Stirling engine just before the final spin-off on Friday, Feb. 2. Eric D. Schmiedl—The Tech May. 8, 2016 Facebook Twitter Reddit Print 2.670 professor Douglas P. Hart adjusts Alison S. Greenlee's '09 Stirling engine just before the final spin-off on Friday, Feb. 2. Eric D. Schmiedl—The Tech