Jean Lemaître
Jean Lemaître was a mechanical engineer from the Nord Belge Railway, who developed a Steam locomotive exhaust system.
The Lemaître Exhaust featured 5 nozzles in a circular pattern exhausting up a large-diameter stack, with a variable area nozzle exhausting up the center, and improved efficiency by about 10%.[1]
The design was later improved by Livio Dante Porta, who created the Lempor and Lemprex, named after a combination of their two names.