| 摘要 |
<p>The acoustic barrier (10) includes an acoustic insulation body (20) composed of a substantial proportion of uncomminuted rice hulls and a casing (13) enclosing the body of rice hulls. The casing (13) provides strength, permeability to sound waves, and inhibits access of vermin and birds to the body (20). The rice hulls may be bonded together or not. The density of the body (20) can be chosen to attenuate expected noise frequencies. Multiple layers of different densities are possible. Perforations (17) in the casing faces (11, 12) pass sound to the body (20) and impede bird and vermin access. An air gap (22) between the casing (13) and body (20), and an intervening screen or membrane can be provided. A method of noise reduction is also provided.</p> |
