| Abstract: | A structure includes a substrate and a coating applied over the
substrate, the coating containing particles sized between 30 and 250
micrometers. A proportion of the particles to the carrier is between 40
and 70 by volume percentage. In response to excitation of the structure
by a controllable excitation source, a first instrument monitors behavior
of the particles to determine a first condition of the structure thereby.
In response to an absence of excitation of the structure by the
controllable excitation source, a second instrument monitors behavior of
the particles to determine a second condition of the structure thereby. |