A blood alcohol concentration (BAC) or blood alcohol level (BAL) reflects the amount of alcohol in the body. Food, type and quantity of beverage, weight, sex, and rate of elimination determine the BAC after the consumption of alcohol.
The process of oxygen transfer in the gills of a fish is a good example of the benefits of countercurrent exchange. As oxygen poor blood meets an opposed flow of oxygen rich water, the oxygen begins to diffuse out of the water and into the blood stream.
Primary flow element. A primary flow element is the element of a flow meter that serves to indicate the quantity or velocity of flow. For example, in the case of an orifice flow meter, the differential pressure across the orifice plate is the primary flow element.