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.
Signs and symptoms of SSIs. Any SSI may cause redness, delayed healing, fever, pain, tenderness, warmth, or swelling. These are the additional signs and symptoms for specific types of SSI: A superficial incisional SSI may produce pus, which doctors call purulent discharge, from the wound site.