An apparatus or system includes a component that generates or transfers noise having a frequency within a noise frequency range. The component may include a boundary. The apparatus or system may be an engine in some examples. The engine may additionally in...

A multistage Stirling engine 1 mounted on an automobile provided with an internal combustion engine has two cylinders 4 and 5. Displacer pistons 6 and 7 and power pistons 8 and 9 are slidably fitted in the two cylinders 4 and 5, respectively. The exhaust g...