Composite structures can be designed with specific parameters for efficient sound absorption in frequency bands; however, determining the optimal and topology to maximize is a computationally challenging task. In this work, semi-empirical model constructed predict performance of composite consisting open-cell foam perforated plates. The calculated results are good agreement experimental carried...

A device is described which consists of a bonded Plexiglas-silicone rubber plate, perforated to hold capillary pipettes in register with the wells of a plastic tray to be inoculated. Pipette contents are simultaneously discharged by positive air pressure, initiated by closing an exhaust port with the thumb.