06413_19 - S SabatierSenderens process A method of organic...

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S Sabatier–Senderens process A method of organic synthesis employing hydrogenation and a heated nickel cata- lyst. It is employed commercially for hy- drogenating unsaturated vegetable oils to make margarine. It is named after Paul Sabatier (1854–1941) and Jean-Baptiste Senderens (1856–1937). saccharide See sugar . saccharin A white crystalline solid, C 7 H 5 NO 3 S, m.p. 224 ° C. It is made from a compound of toluene, derived from petroleum or coal tar. It is a well-known arti Ü cial sweetener, being some 500 times as sweet as sugar (sucrose), and is usually marketed as its sodium salt. Be- cause of an association with cancer in lab- oratory animals, its use is restricted in some countries. Saccharomyces An industrially impor- tant genus of yeasts. S. cerevisiae , of which there are at least 1000 strains, is used in baking ( see baker’s yeast ), brewing, and wine making; it is also used in the pro- duction of * single-cell protein and ergos- terol, a steroid. The other main yeast used in the production of beer is S. uvarum (or carlsbergensis ); it is distin- guished from S. cerevisiae by its ability to ferment the disaccharide melibose using α -galactosidase, an enzyme not produced by S. cerevisiae . saccharose See sucrose . sacculus (saccule) A chamber of the * inner ear from which the * cochlea arises in reptiles, birds, and mammals. It bears patches of sensory epithelium con- cerned with balance ( see macula ). Sachse reaction A reaction of methane at high temperature to produce ethyne: 2CH 4 C 2 H 2 + 3H 2 The reaction occurs at about 1500 ° C, the high temperature being obtained by burning part of the methane in air. Sachs–Wolfe effect A phenomenon, predicted in 1967 by R. K. Sachs and A. M. Wolfe, in which density Û uctuations asso- ciated with quantum-mechanical effects in the early universe caused ‘ripples’ in the cosmic microwave background radia- tion. It was Ü rst observed by the * COBE satellite and analysed in detail by * WMAP. sacral vertebrae The vertebrae that lie between the lumbar and the caudal verte- brae in the * vertebral column. The func- tion of the sacral vertebrae is to articulate securely with the * pelvic girdle, and they are usually fused to form a single bone (the sacrum ) to provide a Ü rm support. The number of sacral vertebrae varies from animal to animal. Amphibians have a single sacral vertebra, reptiles have two, and mammals have three or more. sacri Ü cial protection (cathodic protec- tion) The protection of iron or steel against corrosion ( see rusting ) by using a more reactive metal. A common form is galvanizing ( see galvanized iron ), in which the iron surface is coated with a layer of zinc. Even if the zinc layer is scratched, the iron does not rust because zinc ions are formed in solution in prefer- ence to iron ions. Pieces of magnesium alloy are similarly used in protecting pipelines, etc.
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This note was uploaded on 05/29/2009 for the course CIVIL ENG 12345 taught by Professor Xhfxfh during the Spring '09 term at Amirkabir University of Technology.

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06413_19 - S SabatierSenderens process A method of organic...

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