Figure 7.
Sound absorption coefficient for composite materials: (a) Hemp composite materials; (b) Materials containing sapropel, moss, and flax; (c) Materials containing sapropel, vermiculite, and flax.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.