A total of as many as 900 test steel and concrete test panels, held in specially designed frames, are hanging in the boisterous waters of the lower Columbia to test the resilience over time of three silicon-based coatings.
A total of as many as 900 test steel and concrete test panels, held in specially designed frames, are hanging in the boisterous waters of the lower Columbia to test the resilience over time of three silicon-based coatings.