The use of differential pressure as an inferred measurement of a liquid's rate of flow is well known. Differential pressure flowmeters are, by far, the most common units in use today. Estimates are that over 50 percent of all liquid flow measurement applications use this type of unit.
Between 1% and 15% of people globally are affected by kidney stones at some point in their life. In 2013, 49 million cases of occurred, resulting in about 15,000 deaths. They have become more common in the Western world since the 1970s. Generally, more men are affected than women.
1 Nephrolithiasis is the medical term for kidney stones. 2  One in every 20 people develop kidney stones at some point in their life. 3  Kidney stones form when there is a decrease in urine volume and/or an excess of stone-forming substances in the urine.  Dehydration is a major risk factor for kidney stone formation.