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.
In segmental vitiligo, the white patches are usually exclusive to only one side of the body, and do not usually spread or worsen after the first six months of appearance. Focal. In this type, the depigmentation is limited to one or only few areas of the body.itiligo. Vitiligo is a chronic disease that causes skin depigmentation. The disease promotes the development of unsightly white patches, and can severely alter ones appearance. The body's white blood cells attack the skin's pigment cells due to a genetic mutation.