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.
Causes of Vitiligo. Melanin is the pigment that gives the skin its characteristic color. Vitiligo is caused by a loss of pigment in the skin, due to destruction of pigment-forming cells known as melanocytes. The exact cause of the destruction of these cells is not known. One possible explanation might be that the body's immune system destroys the cells, as in other autoimmune conditions.
Vitiligo. 1  Overview Vitiligo: This skin disease often forms on both sides of the body as shown here on the knees. 2  Symptoms Vitiligo: It is common to have vitiligo on the hands. 3  Causes Vitiligo can affect your hair: The patch of white hair near this 22-year-old man's part is caused by vitiligo.