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.
Hardness versus loading rate. The mean and standard deviation and number of indentations are shown for each test set. Much of the variability in an individual hardness result is due to the standard uncertainty (±1 standard deviation) of the average diagonal length measurement as shown on the left of each data set.
