Edema has many possible causes: 1  Prolonged standing or sitting, especially in hot weather, can cause excess fluid to accumulate in the feet, ankles and lower legs. 2  Tiny valves inside the veins of the legs can become weakened, causing a common problem called venous insufficiency.
Cars with nitrous-equipped engines can be identified by the purge of the delivery system that most drivers perform prior to reaching the starting line. A separate electrically operated valve is used to release air and gaseous nitrous oxide trapped in the delivery system.
Diving with non-air gas mixtures: Nitrox, Heliox, Trimix what is nitrox? Nitrox is a gas mixture of oxygen and nitrogen, but with a higher oxygen percentage than found in ordinary air. As a result of its higher oxygen concentration, the percentage of nitrogen in nitrox is always lower than in air. There are two standard mixtures of Nitrox recognized by NOAA for diving: Nitrox I and Nitrox II (see Table 1).