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.
Flowback water (aka backflow water) is the murky, salty water from fracing natural gas wells. It consists of frac fluid which returns to the surface (aka the frac load recovery) as well as produced water. This water contains clay, dirt, metals, chemicals and even diesel that may have been added. The frac load recovery can be anywhere from 15-40% percent of the volume of fluid that is injected, that is forced down a well, and it flows back over a period of 3-4 weeks after fracing--most of it within 7 to 10 days. More than half of the frac fluid remains in the formation.