Professor Sridhar has solved an outstanding problem in macromolecular science by conceiving the filament stretching rheometer for measuring extensional viscosity. This significant breakthrough led to counterintuitive results and a new understanding of macromolecular chain conformation during deformation and triggered work in new areas. Several universities and industrial laboratories have adopted this technique. His contribution to multi-phase reaction engineering illuminates, in an incisive way, the inter-relationship between mass transfer and chemical reaction, in industrially important reactions. He has provided new strategies for using laboratory experiments for astute reaction design in which the local reaction environment can be tailored to meet specific goals.