Materials Handbook 15th ed - G. Brady_ H. Clauser_ J. Vaccari (McGraw-Hill_ 2002) Episode 12 pps

mixture which consists of a suspension of solid grains of the resin or gum in the liquid plasticizer. The plasticizer is in that sense a solvent, but unlike an ordinary solvent the plasticizer remains with the cured resin to give added properties to the materials, such as flexi- bility. Dibutyl phthalate, a water-white, oily liquid of specific gravity 1.048, boiling point 644°F (340°C), and composition C 16 H 22 O 4 , is a plasticizer for Buna N rubber and polyvinyl chloride plastics. Monoplex DOA, of Rohm & Haas Co., used to give flexibility to vinyl resins at low temperatures, is diisooctyl adipate. It has a flash point of 400°F (204°C) and freezing point of 131°F (55°C). Diiso-nonyl phthalate and diisodecyl phthalate are high-molecular-weight plasticizers for flexible polyvinyl chloride. An aprotic solvent is a sol- vent that contains no hydrogen, such as selenium oxychloride, a liq- uid of composition SeOCl 2 . Such solvents are used in electronic applications where the energy deflection of free protons would be undesirable. Phosphorus oxychloride, POCl 3 , is an aprotic solvent used with neodymium in liquid lasers to give high light-beam effi- ciency. SORBITOL. A hexahydric alcohol, (CH 2 OH) 5 CHOH, which occurs naturally in many fruits, but is now made on a large scale by the direct hydrogenation of corn sugar, or dextroglucose. It is a white, odorless, crystalline powder of faint sweet taste. It melts at 208°F (97.7°C) and is easily dissolved in water. It is used as a humectant, softener, and blending agent; for the production of synthetic resins, plasticizers, and drying oils; and as an emulsifier in cosmetics and pharmaceuticals. It is digestible and nutritive and is used in confec- tionery to improve texture and storage life by inhibiting crystal growth of the sugar, and in dietary foods as a substitute for sugar. Sorbo and Arlex, of ICI Americas, Inc., are water solutions of sor- bitol. Neosorb is a granular form from Roquette Corp. that is used for tabletting drugs. Mannitol is an isomer form of the alcohol and is produced in granular form for pharmaceuticals and foodstuffs as a binder. In the form of a free-flowing powder, it is used as an anticak- ing agent in pharmaceuticals and foodstuffs where a silica or other mineral-based agent is undesirable. The polysorbates are esters of sorbitol. Polysorbate 80, of Hodag Chemical Corp., is such a mater- ial used as an emulsifier in prepared mixed food for improving tex- ture and stability. Hex, a metal-cleaning and protective agent, is a phosphoric acid ester of sorbitol. Sorbitol additives are also used to impart clarity to polypropylene for packaging food and other products. EC-1, of EC Chemical of Japan and marketed outside Asia by Milliken Chemicals as Millad 3905, is based on dibenzylide technology. Though it provides excellent odor and 880 SORBITOL Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses taste quality, limited clarity and significant plateout (premature volatilization in processing) has retarded its use. Gell All MD, of New Japan Chemical, and Millad 3940, of Milliken, are based on dimethyl- benzylidine technology. They improve clarity and reduce plateout but pose odor and taste problems. Also based on this technology is Schering Polymer Additives’ (United Kingdom) Geniset MD. It improves clarity, reduces plateout, and lessens odor and taste prob- lems. NC-4, of Mitsui Toatsu of Japan and based on bis (p-ethylben- zylidene) technology, virtually eliminates plateout, significantly improves clarity, and, by removing alkyl impurities, improves odor and taste. Milliken’s Millad 3988, a sorbitol-acetal additive, also excels in terms of clarity, plateout, and odor and taste performance. SOUND AND VIBRATION INSULATORS. Materials used for reducing the transmission of noise. Insulators are used to impede the passage of sound waves, as distinct from isolators used under machines to absorb the vibrations that cause the sound. For factory use the walls, partitions, and ceilings offer the only media for the installation of sound insulators. All material substances offer resistance to the pas- sage of sound waves, and even glass windows may be considered as insulators. But the term refers to the special materials placed in the walls for this specific purpose. Insulators may consist of mineral wool, hair felt, foamed plastics, fiber sheathing boards, or simple sheathing papers. Sound insulators are marketed under a variety of trade names, such as Celotex, made from bagasse, and Fibrofelt, made from flax or rye fiber. Wheat straw is also used for making insulating board. Sound insulators are often also heat insulators. Linofelt is a sound- and heat-insulating material used for walls. It consists of a quilt of flax fiber between tough waterproof paper. It comes in sheets 0.3125 to 0.75 in (0.80 to 1.91 cm) thick. Torofoleum is a German insulating material made from peat moss treated with a waterproof- ing agent. It withstands temperatures up to 230°F (110°C), is porous, and has a density of less than 1 lb/ft 3 (0.005 kg/m 3 ). Fiber metal, of Technetics Corp., comprises randomly interlocked similar metal fibers, with the fibers bonded by sintering at all contact points. Similar to nonwoven textile felts, its trade name is Feltmetal, and it is available in sheet form in various fibers, thickness, and porosity. Stainless steel (316 and 347) and aluminum-alloy fibers are used mainly for noise reduction of aircraft turbines, turbine blowers, and high-speed fans. Noise reduction is by resistive absorption, by which the amplitude of sound waves is reduced by converting most of the acoustic energy into heat. Other applications include abradable seals, using nickel alloy (Hastelloy X) fibers, and high-temperature thermal insulation, using an iron, chromium, aluminum, and yttrium alloy. SOUND AND VIBRATION INSULATORS 881 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses Vibration insulators, or isolators, to reduce vibrations that pro- duce noises, are usually felt or fiberboards placed between the machine base and the foundation, but for heavy pressures they may be metal wire helically wound or specially woven, deriving their effec- tiveness from the form rather than the material. Keldur, of Quimby & Co., is a fibrous insulating material made up in sheets 0.75 in (1.91 cm) thick, with a resilient binder. Korfund isolator, of Korfund Dynamics Co., is a resilient mat of cork treated with oil and bound in a steel frame. It will take loadings up to 4,000 lb/ft 2 (19,528 kg/m 2 ). Vibro-Insulator, of Karman Rubber Co., is an isolator of Ameripol synthetic rubber. Plastic foams in sheet or flexible tape form are also used as isolators for instruments. Isoloss, of E-A-R Specialty Composites, is a high-density urethane foam for shock absorption. Viscolas, of the same company, is sheet or molded viscoelastic poly- mers for shock absorption. Isodamp, also of E-A-R, is vinyl-based sheet and foam for vibration and shock control. SOYBEAN OIL. Also known as soya bean oil. A pale-yellow oil obtained by expression from the seeds of the plant Glycine soya, native to Manchuria but grown in the United States. Soybean oil is a linolenic acid oil; in contrast, the other three major oilseed oils—cottonseed, peanut, and sunflower—are oleic-linolenic acid oils, because they con- tain more than 50% of these fatty acids. It is primarily a food oil but has an undesirable off-flavor unless highly purified. It is also used as a drying oil for linoleum, paints, and varnishes, or for mixing with lin- seed oil, although the untreated oil has only half the drying power of linseed oil. It is also used in core oils and in soaps. The bean contains up to 20% oil. The average yield factor is 15%, but by trichlorethylene extraction a bushel of beans will yield 11 lb (5 kg) of oil and 46 lb (21 kg) of high-protein meal containing less than 1% oil. The oil content decreases in warm climates. Southern-grown soybeans contain 2 to 5% less oil than those grown in Illinois. The usual conversion factor is 8.5 lb (4 kg) of oil and 48 lb (22 kg) of meal per bushel of beans. The oil is easy to bleach, has good consistency as a food oil, and does not become rancid easily, but has less flavor stability than many other oils. There are 280 varieties of the bean grown in the United States and 2,500 varieties listed. The pods contain two or three beans which range in color from light straw through gray and brown to nearly black. Most varieties are straw-colored or greenish yellow. The stalks and leaves of the plant contain much nitrogen, and about half of the crop is usu- ally plowed under for fertilizer. The specific gravity of the oil is about 0.925, iodine value 134, and it should have a maximum of not more than 1.5% free fatty acids and not more than 0.3 moisture and volatile matter. The fractionated oil 882 SOYBEAN OIL Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses yields 15% cut soybean oil of an iodine value of 70 to 90, used for soaps, lubricants, and rubber compounding; 72% selected-acid oil of an iodine value of 145 to 155, used for varnish and paint oils alone or in blends with other oils, or for glycerin making; 13% bottoms, used for soaps, lubricants, and giving a by-product pitch used in insulation and mastic flooring. Snowflake oil, of Archer-Daniels-Midland Co., is a heavy-bodied, oxidized soybean oil for paints. It has a specific gravity of 0.986 to 0.989 and iodine number from 64 to 95. Special kettle-bodied and blown grades for use in coatings, caulks, and put- ties are available from Werner G. Smith, Inc. Soyalene, of the same company, is an alkali-refined soybean oil for varnishes. The specific gravity is 0.924, and the iodine number is 130. Epoxidized soybean oil is used in vinyl and alkyd resins as a plasticizer and to increase heat resistance. A very large use of soybean oil is in the making of margarine. Soybean meal is the product obtained by grinding the soybean chips from the expeller process, or the soybean oil cake from the hydraulic process. The meal is marketed as stock feed or fertilizer. It is chiefly used as a protein feed for dairy cattle, but it is inferior to fish meal for poultry, as it lacks the mineral salts and vitamins of fish meal. Soybean meal hardened with formaldehyde is used as a filler with wood flour in plastics to give better flow in molding. Gelsoy is a protein gel extracted from soybean meal. It is used in foodstuffs as a thickening agent, and is also used as a strong adhesive. Genistein, found in soybean curd, called tofu, and in soy milk, soy protein iso- lates, and most soy flours, may be an anticarcinogen. Soy sauce does not contain the substance, but its principal flavor component contains a substance called HEMF, also a possible anticarcinogen. Soybean flour for bakery food products for the U.S. market is made from meal that has been treated by acidulated washing to remove the sol- uble enzymes and sugars that carry the taste. Meal produced by heat pro- cessing averages 40% protein and 20 fats, while meal from solvent extraction has 42 to 50 protein and a maximum of 2.5 fats. Further pro- cessing of the meal to remove sugars and other materials varies the final protein content of the flour, and meals from different types of beans vary in content. The protein content can be increased by removing the soy hulls before (front-end dehulling) or after (tail-end dehulling) solvent extraction. The Promax and Isopro soybean flours, of Griffith Laboratories, for high-protein additions to foodstuffs, contain 70% protein with all flavor removed, and are high in lysine. They have a pH of 5.5 and 7.0, respec- tively. Soy protein, of General Mills, used in canned soups and meat products, is toasted to eliminate all enzyme activity. It contains 50% pro- tein with 2 lecithin and 3 lysine. Promine, of Central Soya Co., is a 93% concentrate of soybean proteins, used for thickening and enriching soup SOYBEAN OIL 883 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses mixes. Supro 610, of Ralston Purina Co., is a spray-dried powder, 95% protein, with a light cream color and no bitter flavor. SPECULUM METAL. An alloy formerly used for mirrors and in optical instruments. It contains 65 to 67% copper, the balance tin. It takes a beautiful polish and is hard and tough. An old Roman mirror con- tained about 64% copper, 19 tin, and 17 lead; and an Egyptian mirror contained 85% copper, 14 tin, and 1 iron. The old Greek mirrors were carefully worked out with 32% tin and 68 copper. They had 70% of the reflecting power of silver, with a slight red excess of reflection that gave a warm glow, without the blue of nickel or antimony. This alloy is now plated on metals for reflectors. A modern telescope mirror con- tains 70% copper and 30 tin. Chinese speculum contains about 8% antimony and 10 tin. Speculum plate, which has been advocated by the Tin Research Institute for electroplating, to give a hard, white, corrosion-resistant surface for food processing equipment and optical reflectors, has 55% copper and 45 tin. It is harder than nickel and retains its reflectivity better than silver. SPERM OIL. The waxy oil extracted from the head cavity of the sperm whale, Physeter breviceps and P. catadon, and the Bottlenose whale, P. macrocephalus. Sperm whales have teeth and feed in deep water on squid and large animal life. The male sperm whale attains a length of 60 ft (18 m) and the female about 38 ft (12 m). The spermaceti is first separated out, leaving a clear, yellow oil. It is purified by being pressed at a low temperature. It is graded according to the temperature of pressing. A good grade of sperm oil has a specific gravity of 0.875 to 0.885 and a flash point above 440°F (227°C). Oils from other whale species, such as the humpback, fin, and sulfurbottom, have a specific gravity of 0.91 to 0.93. Inferior grades of sperm oil may be from sperm whale blubber. Commercial sperm oil is likely to be one-third head oil and two-thirds body oil. Sperm oil differs from fish oil and whale oil in consisting chiefly of liquid waxes of the higher fatty alcohol esters and not fats. Sperm oil absorbs very little oxygen from the atmosphere and resists decomposition even at temperatures above 400°F (204°C), and it will pour below its cloud point of 38 to 45°F (3 to 7°C). It wets metal sur- faces easily. It is thus a valuable lubricating oil. It was formerly used as a lamp oil, burning with a white shining flame. It is also an excellent soap oil. Sperm 42, of Werner G. Smith, Inc., is a sperm oil with carbon chains of C 10 to C 22 , and it is emulsifiable in cold or warm water. Sulfonated sperm oil is used as a wetting agent for textiles, and it is also valued for cutting oils, crankcase oil, and high-pressure lubricants. Smithol 25, of the same company, is a 884 SPECULUM METAL Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses synthetic fatty-acid oil resembling sperm oil and having the same uses. It is a light-colored, odorless oil with high viscosity, a low pour point of Ϫ16°F (Ϫ27°C), and an iodine value of 105. Maysperm is a sulfurized sperm-oil replacement from Mayco Oil & Chemical Co. It is used as a lubricant additive. Spermaceti is the white, crystalline flakes of fatty substance, or wax, that separate out from sperm oil on cooling after boiling. It is cetyl palmitate, a true wax, and does not yield glycerin when saponified. It is purified by pressing, and the triple-refined is snow white. It is also separated out from dolphin-head oil. Spermaceti is odorless and tasteless, has a melting point of 43°C, and is insoluble in water, but soluble in hot alcohol. It burns with a bright flame. It was formerly used for candles but now is employed chiefly as a fine wax for ointments and compounds. Sperm oil and spermaceti are inedible and indigestible. Cetyl alcohol, C 16 H 33 OH, originally obtained from spermaceti, is now made synthetically from ethyl palmitate. A synthetic spermaceti wax from Sherex Chemical Co., called Starfol Wax GG, is used in cosmetic emollients, drawing compounds, finishing aids, lubricants, and leather treatment. Synaceti 116 is a fine-chemical and pharmaceutical grade from Werner G. Smith, Inc. White flakes of a 90% cetyl palmitate grade, Kessco 653, from Stepan Chemical Co., are employed as a viscosity modifier. Straplitz is a similar material from Strahl & Pitsch, Inc. A substitute wax that is compositionally different from spermaceti is extracted from the jojoba plant. Hydroba-70 is such a material, produced by Jojoba Growers & Processors, Inc. SPICE. An aromatic vegetable substance, generally a solid used in powdered form, employed for flavoring foods. There is no sharp divid- ing line between flavors and spices, but in general a spice is a material that is used to stimulate the appetite and increase the flow of gastric juices. Spices are not classified as foods in themselves, having little food value, but as food accessories. Pepper is distinctly a spice, though not grouped with the spices. Some spices are also used widely as fla- vors and in perfumes, and in medicine either for antiseptic or other val- ues or to disguise the unpleasant taste of drugs. A condiment is a strong spice, or a spice of sharp taste, although the word is often erro- neously applied to any spice. A savory is a fragrant herb or seed used for flavor in cooking. Spices are obtained from the stalks, bark, fruits, flowers, seeds, or roots of plants. Microground spices, used to give uniform distribution in the quantity manufacture of foodstuffs, are spices ground to microscopic fineness in a roller mill. The most popular spices in the United States, in the order of quantity used, are: cinna- mon, nutmeg, ginger, cloves, allspice, poppy seed, and caraway seed. SPICE 885 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses Since ground spices lose flavor rapidly by the loss of volatile oils, the particles are sometimes coated with dextrose or a water-soluble gum. Spisoseals are ground spices with coated particles. Allspice, also known as pimento and Jamaica pepper, is the dried, unripe fruit of the small evergreen tree Pimenta officinalis of the myrtle family growing in the West Indies and tropical America. The fruit is a small berry which when dried is wrinkled and reddish brown. It has a flavor much like a combination of clove, nutmeg, and cinnamon. Pimento oil is a fragrant essential oil distilled from the berries, which contain 4%. It contains eugenol and cineol and is used in flavors, in bay rum, and in carnation perfumes. Coriander is the dried fruit of the perennial plant Coriandrum sativum grown in the Mediterranean countries and India. It is one of the oldest spices and has a pleasant, aromatic taste. Oil of coriander, extracted from the dried seed, is used in medicine, beverages, and flavoring extracts. It has a higher aromatic flavor than the fruit. Savory is a fragrant herb of the mint family, Satureia hortensis, used in cooking, and in medi- cine as a carminative. It contains carvacrol, a complex phenol also occurring in caraway and camphor. The word savory also designates other herbs used directly in foods as flavors. Celery seed, used as a savory, is from the plant Apium graveolens. The best-quality leafstalks, known as celery, are bleached white and eaten raw or cooked. The plant is widely grown for seed in France and Spain. Celery-seed oil is a pale-yellow oil extracted from the seeds and used as a flavor and in perfumery. Fennel is the dried, oval seed of the perennial plants Foeniculum vulgare and F. dulce. The stalks of the latter are blanched and eaten as a vegetable in Europe. Fennel is used as a flavoring in confectionery and liqueurs, and as a carminative in medicine. Fennel oil is a pale yellowish essential oil with specific gravity of 0.975, distilled from the seed. It has an aromatic odor and a camphorlike taste with a secondary sweetish, spicy taste. It contains fenchone, C 10 H 16 O, an isomer of camphor, with also pinene, cam- phene, and anethole, or anise camphor, C 3 H 5 C 6 H 4 OCH 3 . The latter is used in dentifrices and pharmaceuticals. Fenugreek is the seed from the long pods of the annual legume Trigonella foenum-graecum, native to southern Europe. It is used in curries, in medicine, and for making artificial maple flavor. Oregano, used as an ingredient in chili powder and as a spice in a variety of dishes, is the pungent herb Coleus amboinica. Dill seed, from the herb Anethum graveolens, of the parsley family, is used as a condiment for pickles. Dill leaves are used as seasoning for soups, sauces, and pickles. Dill oil, extracted from the whole herb, is used as a flavor in the food industry. It resembles caraway oil and has a finer flavor than dill-seed oil, which is more plentiful, but dill flavor prepared from the whole seed is stronger. Dill is grown in the 886 SPICE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses central United States and in central Europe. Cardamon is the highly aromatic and delicately flavored seeds of the large perennial herb Elettaria cardamomum, of India, Ceylon, and Central America. The seeds are used in pickles, curries, and cakes, and the oil is employed as a flavor. Garlic is the root bulb of the lily Allium sativum, used as a condiment, and also used in medicine as an expectorant under the name of allium. It contains allyl sulfide, a liquid of composition (CH 2 :CHCH 2 ) 2 S, which gives it a pungent odor and taste. Allicine, extracted from garlic, is used in medicine as an antibacterial. It is an oily liquid with a sharp garlic odor. Cumin is the seed of Cuminum cyminum, the true cumin, and Nigella sativa, the black cumin, both of India. The seed is used in confectionery and in curries. A kind of black cumin known as shiah zira, from the plant Carum indicum of India, is superior in taste and fragrance to ordinary cumin. Caraway is the spicy seed of the bien- nial herb C. carvi of Europe and north Africa. The seeds are used on cookies. Caraway oil, distilled from the seeds, contains carvone and limonene, and in combination with cassia gives a pleasant odor. It is used in soap, perfumes, and mouthwashes. Sage is the grayish-green, hairy leaves of the shrublike plant Salvia officinalis used as a spice. It is cultivated extensively in the Mediterranean region. Oil of sage is used in perfumery. Clary sage oil is distilled from the flowers of S. sclarea of France, Italy, and north Africa. It has the odor of a mixture of ambergris, neroli, and lavender, and is used in flavoring vermouth liquor and muscatel wines, and in eau de cologne. Sassafras is some- times classified as a spice but is a flavor. It is the aromatic spicy bark of the root of the tree Sassafras albidum which grows wild in the eastern United States. It is used mostly for making root beer, but also for flavoring tobacco, and in patent medicines. Sassafras oil is an oil extracted from the whole roots, which contain 2% of the yellow oil, and is used in medicine, perfumery, and soaps. It produces artificial heliotrope. The oil contains safrol, C 10 H 10 O 2 , also produced from brown camphor oil. Brazilian sassafras oil, or ocotea oil, is dis- tilled from the root of the tree Ocotea cymbarum, also of the laurel family. The root yields about 1% of an oil which contains 90% safrol, and has the odor and flavor of American sassafras oil. Sarsaparilla is an oil obtained from the long brown roots of the climbing vine Smilax regellii of Honduras, S. aristolochiaefolia of Mexico, and other species, all growing in tropical jungles. The roots are used in medi- cine. The oil is used as a flavor. It is odorless, but has an acrid sweet taste. It contains saponins. Wintergreen oil is from the leaves of the small evergreen plant Gaultheria procumbens of the middle Atlantic states. The oil does not exist in the plant but is formed by the reaction between a glucoside and an enzyme when the chopped leaves are steeped in water. It is SPICE 887 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses largely methyl salicylate, C 8 H 8 O 3 . It is used in flavoring candies and soft drinks and in medicine. Hop oil, used to give hop flavor to cereal beverages, and also in perfumes, is obtained from lupulin, a glandular powder found in the female inflorescence of the hop plant, Humulus lupulus. Hops are used directly in making beer, and the oil is produced from the discard hops which contain 0.75% oil. Anise seed is from the annual plant Pimpinella anisum grown in the Mediterranean countries and in India. The best grades come from Spain. The seed is used in flavoring in the baking industry. The dis- tilled oil, anise oil, is used in perfumes and in soaps, and in the liqueur known as anisette. The oil contains choline and is used in medicine as a carminative and expectorant. SPINEL. A magnesium aluminate, MgO и Al 2 O 3 , occurring as octa- hedral crystals of varying colors due to impurities of iron, manganese, or chromium. The best transparent stones are used as gems. Spinel is found as crystals or rolled pebbles in gem gravels with corundum stones; the ruby spinel often occurs with the true ruby. It has a deep-red color, but the variety almandine is violet. Synthetic spinel was originally made in Germany to replace ruby and sapphire for instrument bearings because it is easier to cut and thus conserves diamond abrasive. Spinel is produced by Linde in the forms of drawing dies, gages, wearing parts, orifices, and balls. The composition is MgO и 3.5Al 2 O 3 , and the crystal structure is cubic. The specific gravity is 3.61, the melting point is about 3704°F (2040°C), and the Mohs hardness is 8. Like corundum, it is not attacked by common acids or by sodium hydroxide. The spinel pow- der from which the crystals are flame-grown is made by calcining a mixture of pure ammonium sulfate and ammonium magnesium sul- fate. Much synthetic spinel is used for synthetic gems, the colors being obtained with metal oxides. Small amounts of chromic oxide give the tinted crystals of sapphire, while up to 6% is used for the dark ruby colors. Blue is obtained with oxides of iron and titania, and green is from cobalt oxide. Golden topaz is colored with nickel and magnesium oxides. The aquamarine spinel is tinted with a complex mixture of nickel, cobalt, vanadium, and titanium oxides. SPODUMENE. A mineral of composition Li 2 O и Al 2 O 3 и 4SiO 2 , with some potassium and sodium oxides. It is the chief ore of the metal lithium, but it requires a higher temperature for sintering than lepi- dolite, and the sinter is more difficult to leach. It is found in South Dakota and the Carolinas, and has an average content of 4% Li 2 O, ranging from 2.9 to 7.6%. Crystals of spodumene in South Dakota are 8 to 10 ft (2 to 3 m) long and 1 ft (0.3 m) in thickness, appearing like 888 SPINEL Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses logs of wood, with as high as 6.5% lithium. The specific gravity is 3.13 to 3.20, and the melting point is 2543 to 2597°F (1395 to 1425°C). Spodumene is three times more active than feldspar as a flux in ceramics, giving fluidity, increasing surface tension, and eliminating pinholes. A mixture of 25% spodumene with 75 feldspar is an active vitrifying agent in ceramics. The melting point of the mixture is 2030°F (1110°C), which is below the usual minimum temperature used for chinaware; it thus forms a glaze. Lithospar is a name for feldspar and spodumene from the pegmatites of King’s Mountain, North Carolina. In Germany lithium is obtained from the lithium mica zinnwaldite, which is a mixture of potassium-aluminum orthosilicate and lithium orthosilicate with some iron, and contains less than 3% Li 2 O. Kryolithionite, a mineral found in Greenland, has composition Na 3 Li 3 (AlF 6 ) 2 and contains up to 11.5% Li 2 O. It has a crystal structure resembling garnet. A transparent, emerald-green spodumene in small crystals, known as hiddenite, is found in North Carolina and is cut into gemstones. SPONGE. The cellular skeleton of a marine animal of the genus Spongia, of which there are about 3,000 known species, only 13 of which are of commercial importance. It is employed chiefly for wiping and cleaning, as it will hold a great quantity of water in proportion to its weight, but it also has many industrial uses such as applying glaze to pottery. Sponges grow like plants, attached to rocks on the sea bottom. They are prepared for use by crushing to kill them, scrap- ing off the rubbery skin, macerating in water to remove the gelati- nous matter, and bleaching in the sun. Tarpon Springs, Florida, is the center of U.S. sponge fishing, but most of the best sponges have come from the Mediterranean and Red Seas. The prepared sponge is an elastic, fibrous structure chemically allied to silk. It has sievelike membranes with small pores leading into pear-shaped chambers. The best sponges are spheroidal, regular, and soft. Commercial sponges for the U.S. market must have a diameter of 4.5 in (11.4 cm) or more. Most of the Florida sponges are the sheepswool sponge, Euspongia lachne, used for cleaning and industrial sponging. The Rock Island sponge, from Florida, and the Key wool sponge are superior in texture and durability to the Bahama wool sponge, which is coarser, more open, and less absorbent. The Key yellow sponge is the finest grade. The grass sponge, E. graminea, of the Caribbean, is inferior in shape and texture. The fine honeycomb sponge, Hippiospongia equina, of the Mediterranean Sea, is of superior grade and has been preferred as a bath sponge. About 80% of the north African catch consists of honey- comb sponges, with the remainder Turkey cup sponge, E. officinalis, SPONGE 889 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Materials, Their Properties and Uses [...]... used in prepared mixes Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 912 STARCH for foam-type cakes and pie crusts to improve texture, add volume, and reduce the amount of shortening needed... be kept uniform For flat or spiral springs that are not heat-treated after manufacture, hard-drawn or rolled steels are used These may be tempered in the mill shape Music wire is widely employed for making small spiral springs A much-used straight-carbon spring steel has 1% carbon and 0.30 to 0.40 manganese, but becomes brittle when overstressed ASTM carbon steel for flat springs has 0.70 to 0.80% carbon... amounts of silicon, carbon, and nitrogen The specialty ferritics also include two kinds of virtually nickel-free stainless steel 18Cr-2Mo alloys: (1) low-interstitial, titanium- and/or columbium-stabilized sheet alloys and (2) resulfurized free-machining bar alloys The low-interstitial type, also designated stainless steel 444, is insensitive to intergranular corrosion after welding or exposure to high temperatures,... tailored for superior machinability More-machinable grades from Ugine Stainless and Alloy contain the ternary oxide CaO-Al2O3-SiO2, which, for 303-type grades, increases cutting speed from about 120 0 ft/min (366 m/min) to 2000 to 2300 ft/min (610 to 701 m/min) Cast stainless steels are divided into two classes: those intended primarily for uses requiring corrosion resistance and those intended mainly... and heat-treating fixtures, turbine blades, and molds for glass There are many specialty wrought ferritic stainless steels Crucible Stainless Steel’s Sea-Cure is a low-carbon titanium-stabilized alloy containing 26% chromium, 3 molybdenum, and 2.5 nickel developed for seawater condenser tubing A still-higher-chromium (29%) alloy for such applications is Allegheny Ludlum’s vacuuminduction-melted stainless... separators, and the finely divided iron briquetted Unbriquetted sponge iron, with a specific gravity of 2, is difficult to melt because of the oxidation, but briquetted material, with a specific gravity of 6, can be melted in electric furnaces Sponge iron, to replace scrap in steelmaking, is also made from low-grade ores by reducing the ore with coke-oven gas or natural gas It is not melted, but the oxygen is... common True semiaustenitic PH stainless steels include Armco’s PH 1 4-8 Mo, PH 1 5-7 Mo, and 1 7-7 PH Allegheny Ludlum’s AM-350 and AM-355 are also so classified, although they are said not to truly have a precipitation-hardening reaction The Armco steels are lowest in carbon content (0.04% nominally in PH 1 4-8 Mo, 0.07 in the others) PH 1 4-8 Mo also nominally contains 15.1% chromium, 8.2 nickel, 2.2 molybdenum,... applications where resistance to high temperatures is required, stainless steel and high-alloy steels are used But while these may have the names and approximate compositions of standard stainless steels, for spring-wire use their manufacture is usually closely controlled For example, when the carbon content is raised in high-chromium steels to obtain the needed spring qualities, the carbide tends to collect... the United States it is valued for adhesives and coatings, and only a small proportion in globules and flakes, known as pearl tapioca, is used in foodstuffs Gaplek, used for cattle feed in Asia, is not the starch, but is dried and sliced cassava root Tapioca starch may be sold under trade names Kreamgel, used as a thickener for canned soups, sauces, and pastries, is refined tapioca that gives clear... as nitrobenzene or dead oil, was called rack-a-rock It is a mixture of 79% chlorate and 21 nitrobenzene Rack-a-rock special contains, in addition, 12 to 16% picric acid Sprengle explosives were formerly used as military explosives, are very sensitive to friction and heat, and are now valued only for mining or when it is desired to economize on nitrates Cheddite is a French explosive consisting of a . be undesirable. Phosphorus oxychloride, POCl 3 , is an aprotic solvent used with neodymium in liquid lasers to give high light-beam effi- ciency. SORBITOL. A hexahydric alcohol, (CH 2 OH) 5 CHOH, which occurs naturally. SPONGE IRON Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the. Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the