1 Therefore, the idea is to use a set of optimum conditions to get the most efficient yield of ammonia and this involves getting a low % yield (e.g. 8% - 15% conversion) but fast. 2  Described below are the conditions to give the most economic production of ammonia.
A Dr. Mehmet Oz, MD , Cardiology (Cardiovascular Disease), answered. The white patches caused by the skin condition vitiligo can spread to other locations or can stay in one area. The course is unpredictable and varies from person to person. Some people with vitiligo say that new patches form on skin that is under pressure or exposed to friction. This can happen from shaving or rubbing from jewelry or clothing.
Sometimes the hair in these areas also turns white. It happens when the skin's pigment-producing cells called melanocytes die. White patches can appear anywhere on the body (generalized vitiligo) or just in one area (focal vitiligo). Researchers suspect that vitiligo is one of many autoimmune diseases.he exact cause of vitiligo is unknown at this time; however, scientists have several different theories. One theory suggests that vitiligo is an autoimmune disease in which the body destroys melanocytes for no known reason.