One of the most important standards that the API has set is the method used for measuring the density of petroleum. This standard is called the API gravity. Specific gravity is a ratio of the density of one substance to the density of a reference substance, usually water.
The most common symptoms of RSI include: 1  Pain. 2  Tingling. 3  A feeling of restlessness in the joint. 4  Weakness. 5  Throbbing. 6  Stiffness or cramp.
Early symptoms of SCD may include: 1  Painful swelling of the hands and feet, known as dactylitis. 2  Fatigue or fussiness from anemia. 3  A yellowish color of the skin, known as jaundice, or whites of the eyes, known as icteris, that occurs when a large number of red cells hemolyze.