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.
FLOW IN PIPES F luid flow in circular and noncircular pipes is commonly encountered inpractice. The hot and cold water that we use in our homes is pumpedthrough pipes. Water in a city is distributed by extensive piping net-works. Oil and natural gas are transported hundreds of miles by largepipelines.