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.
With the closed cell design, cell geometry connects consistently throughout forming complete and bridging cells. With expansion, the individual cells do not merge to form larger open areas. All connections should connect at least three elements. With the open cell design, cell geometry does not connect consistently throughout, forming incomplete and non-bridged cells. With expansion, the individual cells merge to form larger open areas.
