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Boeing B787 - Dreamliner

As part of its "Quiet Technology Demonstrator 2" project, Boeing adopted several engine noise-reducing technologies for the 787. Among these are a redesigned air inlet containing sound-absorbing materials and redesigned exhaust duct covers whose rims are tipped in a toothed or chevron pattern to allow for quieter mixing of exhaust and outside air.
www.boeing.com

Design: Boeing