Other possible F414 improvements include efforts to reduce engine noise by using either mechanical or fluidic chevrons and efforts to reduce emissions with a new trapped vortex combustor. Chevrons would reduce engine noise by inducing mixing between the cooler, slower bypass air and the hotter, faster core exhaust air. Mechanical chevrons would come in the form of triangular cutouts (or extensions) at the end of the nozzle, resulting in a "sharktooth" pattern. Fluidic chevrons would operate by injecting differential air flows around the exhaust to achieve the same ends as the mechanical variety. A new combustor would likely aim to reduce emissions by burning a higher percentage of the oxygen, thereby reducing the amount of oxygen available to bond with nitrogen forming the pollutant NOx.