The Heat Transfer Memorial Award is bestowed on individuals who have made outstanding contributions to the field of heat transfer through teaching, research, practice, design, service, leadership, and inventions. It functions as a "lifetime achievement award" within the heat transfer community. Ruan was recognized "for the development of original theoretical and computational methods for atomistic and nanoscale heat transfer; for discovering novel heat transfer physics; and for inventions of thermal technologies that have generated significant societal impact and commercial interest."

Ruan studies a broad range of topics related to heat transport, nanotechnology, and machine learning. In 2012, he and Ph.D. student Tianli Feng (now assistant professor at the University of Washington) started tackling four-phonon scattering, a phenomenon which is fundamental to how a material conducts heat. They spent two years to establish the general formulation of four-phonon scattering, and another two years to develop its computational method and predict the importance of four-phonon scattering on thermal conductivity at high temperature. In 2016, they finally reported these findings in a groundbreaking paper on four-phonon scattering. In 2017, they published an influential further study, where they extended the method to first principles and predicted unexpected strong impact of four-phonon scattering on a high thermal conductivity semiconductor called boron arsenide, even at room temperature.

Since then, Ruan has published several other papers on the topic, including demonstrating four-phonon scattering in infrared and Raman spectra for the first time. He has been invited to give more than ten plenary, keynote, tutorial, or invited talks on this topic at ASME, MRS, SPIE, and other international conferences. Funding agencies have recognized the breakthrough by awarding Ruan and Feng significant grants where four-phonon scattering is a key capability; these include multiple awards from DARPA, NSF, and NASA. Ruan and Feng received the Brillouin Medal in 2023 from the International Phononics Society.

These theories have also contributed to Ruan's invention of the world's whitest paint, which has garnered huge media attention from around the world, as well as a Guinness World Records™ title.

The award, given at ASME's 2026 Summer Heat Transfer Conference, was made even more special by a second award given to Tianli Feng. Feng received the Bergles-Rohsenow Young Investigator Award, given to an engineer that is under 36 years of age committed to pursuing research in heat transfer, and demonstrating the potential to make significant contributions to the field of heat transfer. Other Purdue-affiliated researchers to receive this award in past years include David Warsinger, Amy Marconnet, Baratunde Cola, Laurent Pilon, and Andrei G. Fedorov.

Source: Xiulin Ruan, ruan@purdue.edu