Withering

T. W. Clyne and P. J. Withers, M Introduction to Metal Matrix Composites, Cambridge University Press, Cambridge, U.K., 1993. 

N. Ikekawa, in H. Danielsson and. Sjovah, eds.. Steroids andBile Acids, Elsevier Science Pubhshers BV, Amsterdam, the Nethedands, 1985, pp. 199—230 C. Djerassi, in P. Krogsgaard-Larsen, S. Brogger Christensen, and H. Kofod, eds., Alfred Benpon Symposium 20 Natural Products and Drug Development, Munksgaard, Copenhagen, Denmark, 1984, pp. 164—176 N. W. Withers, in P. J. Scheuer, ed.. Marine Natural Products, Vol. V, Academic Press, Inc., New York, 1983, pp. 87—130 C. Djerassi, Pure Appl Chem. 53, 873 (1981). 

BlackTea. The black tea manufacturing process has evolved over hundreds of years, until the early part of the twentieth century, Httie was known about the chemical changes. The process consists of the unit operations of withering, rolling, fermentation, firing, and sorting (4). 

Process Va.ria.tlons. The conventional techniques for tea manufacture have been replaced in part by newer processing methods adopted for a greater degree of automation and control. These newer methods include withering modification (78), different types of maceration equipment (79), closed systems for fermentation (80), and fluid-bed dryers (81). A thermal process has been described which utilizes decreased time periods for enzymatic reactions but depends on heat treatment at 50—65°C to develop black tea character (82). It is claimed that tannin—protein complex formation is decreased and, therefore, greater tannin extractabiUty is achieved. Tea value is beheved to be increased through use of this process. 

S. Guha, C. Kyriacou,J. C. Withers, and R. O. Loutfy, Development of a Tungsten Heavy Mlloj thatFalls by an Mdiabatic Shear Mechanism, Phase 1, Material Electrochemical Research Corp., Tucson, Ariz., ARL-CR-56, Order No. AD-A265867, 120 pp Avail., NTlS, 1993. 

The first report concerning barium compounds occurred in the early part of the seventeenth century when it was noted that the ignition of heavy spar gave a peculiar green light. A century later, Scheele reported that a precipitate formed when sulfuric acid was added to a solution of barium salts. The presence of natural barium carbonate, witherite [14941-39-0] BaCO, was noted in Scodand by Withering. 

Plant and Animal Nutrient. Copper is one of seven micronutrients that has been identified as essential to the proper growth of plants (87). Cereal crops are by far the most affected by copper deficiency (see Wheat and other cereal grains). Greenhouse studies have shown yield increases from 38% to over 500% for wheat, barley, and oats (88) using copper supplementation. A tenfold increase in the yield of oats was reported in France (89). Symptoms of copper deficiency vary depending on species, but often it is accompanied by withering or chlorosis in the leaves that is not ammenable to iron supplementation. In high concentrations, particularly in low pH sods, copper can be toxic to plants. 

Santi, D V, Pogolotti, A L Jr, Newman, E M, Wataya, T In Biomedia nal Aspects of Fluorine Chemistry, Filler, R, Kobayashi, Y, Eds, Kodan-shaLtd Tokyo, and Elsevier Biomedical Amsterdam, 1982, pp 123-142 Withers, S G, Street, I P,Percival, M D a Fluonnated Carbohydrates Chemical and Biological Aspects, Taylor, N F, Ed, ACS Symposium Senes 374, Amencan Chemical Society Washmgton, DC, 1988, pp 59 77... 

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