When lean meets green Dr I.S. Jawahir of the University of Kentucky Center for Manufacturing tells Martin Ashcroft how the concept of sustainable manufacturing has evolved from lean, through green, collecting more Rs as it grows. If you are a certain age you may remember when the three Rs stood for reading, writing and arithmetic (or, as some said, reckoning). It required a little linguistic license, perhaps, but the phrase has been a popular idiom for many years. How the world has changed!