A damping device, consisting of an annular tail-pipe, has been developed. It is applicable in situations wherein acoustic damping is required in combination with low flow resistance. Examples are ventilation systems, turboengines, intake and exhaust systems for internal combustion engines. The device consists of a central tube surrounded by a narrow slit. The central tube has an acoustic mass w...

Impedance tube method is widely used to measure acoustic properties of materials. Although this yields reliable for soft textured materials, uncertainty levels measured hard including biocomposites, can be quite large, mainly due uncertain mounting conditions. Here, the effects conditions on biocomposites in an impedance are investigated. First, nominally identical biocomposite samples with a d...