Inert gas asphyxiation are more uncomfortable in low-oxygen environments that result from inert gas exposure; however, the experience is still less aversive than CO exposure. A typical human breathes between 12 and 20 times per minute at a rate primarily influenced by carbon dioxide concentration, and thus pH, in the blood. With each breath, a volume of about 0.6 litres is exchanged from an active lung volume (tidal volume + functional residual capacity) of about 3 litres. Normal Earth atmosphere is about 78% nitrogen, 21% oxygen, and 1% argon, carbon dioxide, and other gases. After just two or three breaths of nitrogen, the
Gas turbine gas-turbine powered ship was the U.S. Coast Guard's , a cutter commissioned in 1961 that was powered by two turbines utilizing controllable-pitch propellers. The larger High Endurance Cutters, was the first class of larger cutters to utilize gas turbines, the first of which () was commissioned in 1967. Since then, they have powered the U.S. Navy's s, and s, and guided missile cruisers. , a modified , is to be the Navy's first amphibious assault ship powered by gas turbines. The marine gas turbine operates in a more corrosive atmosphere due to the presence of sea salt in air and