For his leadership in separations science and technology; for improving nuclear fuel recycling and waste removal; and for leading the development process that was instrumental in the cleanup of waste at the Savannah River Site.
For environmental-effects research related to energy technologies and their use, focusing on the impacts of climate and atmospheric changes on the physiology, growth, and biogeochemical cycles of North American forest ecosystems.
For pioneering research and development of new materials for advanced energy technologies, including materials for (a) the storage of nuclear waste, (b) the solid-state generation of electrical power directly from heat, and (c) the lossless transport of electricity.
For internationally recognized contributions in distributed and cluster computing, including the development of the Parallel Virtual Machine and the Message Passing Interface standard now widely used in science to solve computational problems in biology, physics, chemistry, and materials science.
For applying molecular beam techniques to study chemically reactive collisions, helping to lay the foundation for the present field of chemical dynamics, and for pioneering studies in accelerator-based atomic physics, ion-solid interactions, and the channeling of ions, electrons and positrons in crystalline solids.
For discoveries of fundamental importance in mammalian genetics, as well as for studies of genetic and developmental effects in mice, which have provided a broad basis for assessment of the genetic risk to humans from radiation and chemicals, including the development of genetic and early developmental tests now used worldwide.
For original studies of the genetic effects of radiation in mammals. A world authority on mammalian mutagenesis, he and co-workers provided the experimental basis for estimating the genetic hazards of radiation to man and for the corresponding recommendations of national and international standards bodies