Materials Handbook 15th ed - G. Brady_ H. Clauser_ J. Vaccari (McGraw-Hill_ 2002) Episode 14 pptx

have made these alloys obsolete. The bearing alloy known in England as motor bronze is a babbitt with about twice the copper of a stan- dard babbitt. One analysis gives tin, 84%; antimony, 7.5; copper, 7.5; and bismuth 1. An old alloy, used in India for utensils and known as bidery metal, contained 31 parts zinc, 1 lead, and 2 copper, fluxed with resins. It was finished with a velvety-black color by treating with a solution of copper sulfate. A white metal sheet now much used for making stamped and formed parts for costume jewelry and electronic parts is zinc with up to 1.5% copper and up to 0.5 titanium. The titanium with the copper prevents coarse-grain formation, rais- ing the recrystallization temperature. The alloy weighs 2% less than copper, and it plates and solders easily. Zilloy-20 is pure zinc with no more than 1% of other elements. In rolled strip it has a tensile strength up to 27,000 lb/in 2 (186 MPa) and elongation of 35%. WILLOW. The wood of the trees Salix coerulea and S. alba, native to Europe, but grown in many other places. It is best known as a mater- ial for cricket bats made in England. The American willows are known as black willow, from the tree S. nigra, and western black willow, from the tree S. lasiandra. The wood is also employed for making artificial limbs and for articles where toughness and non- shrinking qualities are valued. The wood is brownish yellow; has a fine, open grain; and has a density of about 30 lb/ft 3 (481 kg/m 3 ). It is of the approximate hardness of cherry and birch. Japanese willow is from the tree S. urbaniana. It has a closer and finer texture and a browner color. Black willow has a maximum crushing strength paral- lel to the grain of about 1,500 lb/in 2 (10 MPa). Salicin, also called salicoside and saligenin, is a glucoside extracted from several species of willow bark of England and also from the American aspen. It is a colorless, crystalline material of composition (OH) 4 C 6 H 7 и OO и C 6 H 4 CH 2 OH, decomposing at 394°F (201°C) and soluble in water and in alcohol. It is used in medicine as an antipyretic and tonic, and as a reagent for nitric acid. It hydrolyzes to glucose and salicyl alcohol, and the latter is oxidized to salicylic acid, C 6 H 4 (OH)COOH. Aspirin, acetyl salicylic acid, is used as an antipyretic and anal- gesic. WIRE CLOTH. Stiff fabrics made of fine wire woven with plain, loose weave, used for screens to protect windows, for guards, and for sieves and filters. Steel and iron wire may be used—plain, painted, galva- nized, or rustproofed—or various nonferrous metal wires are employed. It is usually put up in rolls in widths from 18 to 48 in (46 to 122 cm). Screen cloth is usually 12, 14, 16, and 18 mesh, but wire cloth in copper, brass, or Monel metal is made regularly in meshes 1040 WILLOW 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 from 4 to 100. The size of wire is usually from 0.009 to 0.065 in (0.023 to 0.165 cm) in diameter. Wire cloth for fine filtering is made in very fine meshes. Mesh indicates the number of openings per inch and has no reference to the diameter of wire. A 200-mesh cloth has 200 open- ings each way on a square inch, or 40,000 openings per square inch (6.4 cm 2 ). Wire cloth as fine as 400 mesh, or having 160,000 openings per square inch (6.4 cm 2 ), is made by wedge-shaped weaving, although 250 wires of the size of 0.004 in (0.010 cm) when placed par- allel and in contact will fill the space of 1 in (2.5 cm). Very fine-mesh wire cloth must be woven at an angle since the globular nature of most liquids will not permit passage of the liquid through microscopic square openings. One wire screen cloth, for filtering and screening, has elongated openings. One way the 0.0055-in (0.0140-cm) wire count is 200 per inch (2.5 cm), while the other way the 0.007-in (0.018-cm) warp wire count is 40 per inch (2.5 cm). Wire fabrics for reentry parachutes are made of heat-resistant nickel-chromium alloys, and the wire is not larger than 0.005 in (0.013 cm) in diameter to give flexibility to the cloth. Wire fabrics for ion engines to operate in cesium vapor at temperatures to 2400°F (1316°C) are made with tantalum, molybdenum, or tungsten wire, 0.003 to 0.006 in (0.008 to 0.015 cm) in diameter, with a twill weave. Meshes to a fineness of 350 by 2,300 can be obtained. Porosity unifor- mity is controlled by pressure calendaring of the woven cloth, but for extremely fine meshes in wire cloth it is difficult to obtain the unifor- mity that can be obtained with porous sintered metals. Where accuracy of sizing is not important, as in gravel or ore screening, wire fabric is made with oblong or rectangular openings instead of squares to give faster screening. High-manganese steel wire is used for rock screens. For window screening in tropical cli- mates or in corrosive atmospheres, plastic filaments are sometimes substituted for the standard copper or steel wire. Lumite screen cloth is woven of vinylidene chloride monofilament 0.015 in (0.038 cm) in diameter in 18 and 20 mesh. The impact strength of the plastic cloth is higher than that of metal wire cloth, but it cannot be used for screening very hot materials. Lektromesh is copper or nickel screen cloth of 40 to 200 mesh made in one piece by electrodeposition. It can be drawn or formed more readily than wire screen, and circular or other shapes can be made with an integral selvage edge. WIRE GLASS. A sheet glass used in building construction for windows, doors, floors, and skylights, having woven wire mesh embedded in the center of the plate. It does not splinter or fly apart as common glass when subjected to fire or shock, and it has higher strength than com- mon glass. It is made in standard thicknesses from 0.125 to 0.375 in WIRE GLASS 1041 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 (0.318 to 0.953 cm) and in plates 60 by 110 in (1.5 by 2.8 m) and 61 by 140 in (1.5 by 3.6 m). Underwriters’ specifications call for a minimum thickness of 0.25 in (0.635 cm). Wire glass is made with plain, rough, or polished surfaces, or with ribbed or cobweb surface on one side for diffusing the light and for decorative purposes. It is also obtainable in corrugated sheets, usually 27.75 in (70.5 cm) wide. Wire glass 0.25 in (0.635 cm) thick weighs 2.25 lb/ft 2 (11 kg/m 2 ). Plastic-coated wire mesh may be used to replace wire glass for hothouses or skylights where less weight and fuller penetration of light rays are desired. Cel-O-Glass, of Du Pont, is a plastic-coated wire mesh in sheet form. WOLLASTON WIRE. Any wire made by the Wollaston process of fine- wire drawing. It consists of inserting a length of bare drawn wire into a close-fitting tube of another metal, the tube and core then being treated as a single rod and drawn through dies down to the required size. The outside jacket of metal is then dissolved away by an acid that does not affect the core metal. Platinum wire as fine as 0.00005 in (0.00013 cm) in diameter is made commercially by this method, and gold wire as fine as 0.00001 in (0.00002 cm) in diameter is also drawn. Wires of this fineness are employed only in instruments. They are marketed as composite wires, the user dissolving off the jacket. Taylor process wire is a very fine wire made by the process of drawing in a glass tube. The process is used chiefly for obtaining fine wire from a material lacking ductility, such as antimony, or extremely fine wire from a ductile metal. The procedure is to melt the metal or alloy into a glass or quartz tube, and then draw down this tube with its contained material. Wire as fine as 0.00004 in (0.00012 cm) in diameter is made, but only in short lengths. WOOD. A general name applied to the cut material derived from trees. A tree, as distinguished from a bush, is designated by the U.S. Forest Service as a woody plant with a single erect stem 3 in (7.6 cm) or more in diameter at 4.5 ft (1.4 m) above the ground, and at least 12 ft (3.7 m) high. But this definition is merely empirical since in the cold climate of northern Canada, perfect, full-grown trees 10 to 15 years old may be only 6 in (15 cm) high. Timber, in general, refers to standing trees, while lumber is the sawed wood used for construction purposes. In construction work the word timber is often applied to large pieces of lumber used as beams. Wood is an organic chemical compound composed of approximately 49% carbon, 44 oxygen, 6 hydrogen, and 1 ash. It is largely cellulose and lignin. The wood of white pine is about 50% cellulose, 25 lignin, and the remainder sugars, resin, acetic acid, and other materials. Wood is produced in most trees by a progressive growth from the out- 1042 WOLLASTON WIRE 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 side. In the spring, when sap flows rapidly, a rapid formation of large cells takes place, followed by a slower growth of hard and close cells in summer. In some woods, such as oak, there is a considerable difference in quality and appearance between the spring and summer woods. In some long-lived trees, such as Douglas fir, there is a decrease in strength between the outside wood with narrow rings and the wide- ringed wood of the interior. Heartwood is the dark center of the tree which has become set, and through which the sap has ceased to flow. Sapwood is the outer, live wood of the tree; unless treated, it has low decay resistance. The grain of sawed lumber results from sawing across the annual growth rings, varied to produce different grains. Wood is seasoned either by exposing it to the air to dry or by kiln drying. The former method is considered to give superior quality, but it requires more time, is expensive, and is indefinite. Numerous tests made at the U.S. Forest Products Laboratory did not reveal any supe- riority in air-dried wood when kiln drying was well done. Solvent sea- soning is a rapid process consisting of circulating a hot solvent through the wood in a closed chamber. California redwood, when sea- soned with acetone at 130°F (54°C), yields tannin and some other chemicals as by-products. Seasoned wood, when dry, is always stronger than unseasoned wood. Tank woods are selected for resis- tance to the liquids to be contained. Tanks for vinegar and foodstuffs containing vinegar, such as pickles, are of white oak, cypress, or west- ern red cedar. Beer tanks are of white oak or cypress. Tanks for aging wine are of redwood, oak, or fir. The traditional violin woods are spruce and curly maple, although sugar maple is also used. The term log designates the tree trunk with the branches removed. Balk is a roughly squared log; plank is a piece cut to rectangular sec- tion 11 in (28 cm) wide; deal is a piece 9 in (23 cm) wide; and batten is a piece 7 in (18 cm) wide. Board is a thin piece of any width less than 2 in (5 cm). Flitch is half a balk, cut in two lengthwise. Scantling is a piece sawed on all sides. Shakes are longitudinal splits or cracks in the wood due to shrinkage or decay. All woods are divided into two major classes on the basis of the type of tree from which they are cut. Hardwoods are from broad-leaved, deciduous trees. Softwoods are from conifers, which have needle- or scalelike leaves and are, with few exceptions, evergreens. These terms do not refer to the relative hardnesses of the woods in these two classes. Hardwood lumber is available in three basic categories: fac- tory lumber; dimension lumber, or dimension parts; and fin- ished market products. The important difference between factory lumber and dimension parts is that factory lumber grades reflect the proportion of the pieces that can be cut into useful smaller pieces, while the dimension grades are based on use of the entire piece. WOOD 1043 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 Finished market products are graded for their end use with little or no remanufacturing. Examples of finished market products are flooring, siding, ties, timbers, trim, molding, stair treads, and risers. The rules adopted by the National Hardwood Lumber Association are considered standard in grading factory lumber. The grades from the highest to the lowest quality are as follows: firsts, the top quality, and seconds, both of which are usually marketed as one grade called firsts and seconds (FAS); selects; and common grades No. 1, No. 2, No. 3A, and No. 3B. Sometimes a grade is further specified, such as FAS one face, which means that only one face is of the FAS quality. Another designation, WHND, sometimes used, means that wormholes are not considered defects in determining the grade. Dimension lumber, generally graded under the rules of the Hardware Dimension Manufacturers Association, are of three classes: solid dimension flat stock, kiln-dried dimension flat stock, and solid dimension squares. Each class may be rough, semifabricated, or fabricated. Rough dimension blanks are usu- ally kiln-dried and are supplied sawn and ripped to size. Surfaced or semifabricated stock has been further processed by gluing, surfacing, etc. Fabricated stock has been completely processed for the end use. Solid dimension flat stock has five grades: clear—two faces, clear—one face, paint, core, and sound. Squares have three grades if rough (clear, select, sound) and four if surfaced (clear, select, paint, sound). There are two major categories of softwood lumber: construction and remanufacture. Construction lumber is of three general types: stress-graded; non-stress-graded, also referred to as yard lumber; and appearance lumber. Stress-graded lumber is structural lum- ber never less than 2 in (5 cm) thick, intended for use where definite strength requirements are specified. The allowable stresses specified for stress-graded lumber depend on the size, number, and placement of defects. Because the location of defects is important, the piece must be used in its entirety for the specified strength to be realized. Stress- graded products include timbers, posts, stringers, beams, decking, and some boards. Typical non-stress-graded lumber items include boards, lath, battens, cross-arms, planks, and foundation stock. Boards, some- times referred to as commons, are one of the more important non-stress-graded products. They are separated into three to five dif- ferent grades, depending upon the species and lumber manufacturing association involved. Grades may be described by number (No. 1, No. 2) or by descriptive terms (construction, standard). First-grade boards are usually graded primarily for serviceability, but appearance is also considered. Second- and third-grade boards are often used together for such purposes as subfloors and sheeting. Fourth-grade boards are selected not for appearance but for adequate strength. The appear- 1044 WOOD 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 ance category of construction lumber includes trim, siding, flooring, ceiling, paneling, casing, and finish boards. Most appearance lumber grades are designated by letters and combinations of letters, and are also often known as select grades. Typical grades of lumber remanu- facture are the factory grades and industrial clears. Factory select and select shop are typical high grades of factory lumber, followed by No. 1, No. 2, and No. 3 shop. Industrial clears are used for cabinet stock, door stock, and other products where excellent appearance, mechanical and physical properties, and finishing characteristics are important. The principal grades are B&BTR, C, and D. Metallized wood is wood treated with molten metal so that the cells of the wood are filled with the metal. Fusible alloys, with melt- ing points below the scorching point of the wood, are used. The wood is immersed in molten metal in a closed container under pressure. The hardness, compressive strength, and flexural strength of the wood are increased, and the wood becomes an electric conductor lengthwise of the grain. Woods are also metallized with a surface coating of metal by vacuum deposition. Sugar pine is one of the most widely used pattern woods for foundry patterns. It replaces eastern white pine, which is scarcer and now usually more costly. Poplar is used for patterns where a firmer wood is desired; cherry or maple is employed where the pattern is to be used frequently or will be subject to severe treatment. Densified wood is also used for patterns required to be very wear-resistant. Mahogany is used for small and intricate patterns where a firm tex- ture and freedom from warpage are needed. However, for small cast- ings made in quantities on gates, aluminum or brass is more frequently used. Excelsior is an old trade name, still used, for continuous, curly, fine wood shavings employed as a packing material for breakable articles. It is light and elastic, and it is also used as a cushioning and stuffing material. It is usually made from poplar, aspen, basswood, or cottonwood. A cord of wood produces about 1,500 lb (680 kg), but it may be made as a by-product from other woodworking. It is also called wood fiber and wood wool, but these terms more properly refer to fibers of controlled size and length used with a resin binder for molding into handles, knobs, and other imitation wood parts. Several plastics are suitable for imitation wood, also called synthetic wood and plastic lumber. And environmental concerns regarding global deforestation have increased prices of certain woods, making plastics more cost-competitive. Some wood for special purposes comes from roots or from bushes. The briar used for tobacco pipes is from the roots of the white heath, Erica arborea, of north Africa. Substitutes for briar are the WOOD 1045 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 burls of the laurel and rhododendron. Yareta, used for fuel in the cop- per region of Chile, is a mosslike, woody plant which grows on the sunny northern mountain slopes at altitudes above 12,000 ft (3,658 m) and requires several hundred years to reach a useful size. WOOD FLOUR. Finely ground dried wood employed as a filler and as reinforcing material in molding plastics and in linoleum, and as an absorbent for nitroglycerin. It is made largely from light-colored soft- woods, chiefly pine and spruce, but maple and ash flours are pre- ferred where no resin content is desired. Woods containing essential oils, such as cedar, are not suitable. Wood flour is produced from saw- dust and shavings by grinding in burr mills. It has the appearance of wheat flour. The sizes commonly used are 40, 60, and 80 mesh; the finest is 140 mesh. Grade 1, used as a filler in rubber and plastics, has a particle size of 60 mesh and a specific gravity of 1.25, but 80 and 100 mesh are also used for plastic filler. Since wood flour absorbs the resin or gums when mixed in molding plastics and sets hard, it is sometimes mixed with mineral powders to vary the hardness and toughness of the molded product. Vast quantities of sawdust are obtained in the sawmill areas. Besides being used as a fuel, it is employed for packing, for finishing metal parts in tumbling machines, for making particleboard, and for distilling to obtain resins, alcohols, sugars, and other chemicals. Some sawdust is pulped, and as much as 20% of such pulp can be used in kraft paper without loss of strength. Hickory, walnut, and oak sawdusts are used for meat smoking, or for the making of liq- uid smoke, which is produced by burning the sawdust and absorb- ing the smoke into water. For the rapid production of bacon and other meats, immersion in liquid smoke imitates the flavor of smoked meat. Some sawdust is used for agricultural mulch and fer- tilizer by chemical treatment to accelerate decay. Bark fuel is shredded bark, flash-dried and pelletized with powdered coal. Particleboard, made by compressing sawdust or wood particles with a resin binder into sheets, has uniform strength in all direc- tions, and a smooth, grainless surface. When used as a core for veneer panels, it requires no cross-laminating. Mechanical pulp for newsprint can be made from sawdust but the quantity available is usually not sufficient. The material known as ground wood, of fine-mesh fibers, is made from cord wood, about 1 ton of fibers being produced from one cord of pulpwood. Plastic wood, usually mar- keted as a paste in tubes for filling cavities or seams in wood prod- ucts, is wood flour or wood cellulose compounded with a synthetic resin of high molecular weight that will give good adhesion but not penetrate the wood particles to destroy their nature. The solvent is 1046 WOOD FLOUR 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 kept low to reduce shrinkage. When cured in place, the material can be machined, polished, and painted. WOOD PRESERVATIVES. These fall into two general classes: oils, such as creosote and petroleum solutions of pentachlorophenol; and waterborne salts that are applied as water solutions. Coal tar cre- osote, a black or brownish oil made by distilling coal tar, is the oldest and still one of the more important and useful wood preservatives. Because it has recently been classified as a carcinogen, its use is expected to decrease. Its advantages are high toxicity to wood-destroying organisms; relative insolubility in water and low volatility, which impart to it a great degree of permanence under the most varied use conditions; ease of application; ease with which its depth of penetration can be determined; general availability and rela- tively low cost; and long record of satisfactory use. Creosotes distilled from tars other than coal tar are used to some extent for wood preservation. For many years, either cold tar or petroleum oil has been mixed with cold tar creosote in various pro- portions to lower preservative costs. Water-repellent solutions containing chlorinate phenols, principally pentachlorophenol, in solvents of the mineral spirit type have been used in commercial treatment of wood by the millwork industry since about 1931. Pentachlorophenol solutions for wood preservation gener- ally contain 5% (by weight) of this chemical, although solutions with volatile solvents may contain lower or higher concentrations. Preservative systems containing water-repellent components are sold under various trade names, principally for the dip or equivalent treat- ment of window sash and other millwork. According to federal specifi- cations the preservative chemicals may not contain less than 5% pentachlorophenol. Standard wood preservatives used in water solution include acid copper chromate, ammoniacal copper arsenite, chromated cop- per arsenate, zinc naphthenate, chromated zinc chloride, and fluor chrome arsenate phenol. These preservatives are often employed when cleanliness and paintability of the treated wood are required. The chromated zinc chloride and fluor chrome arsenate phenol formulations resist leaching less than preservative oils, and are seldom used where a high degree of protection is required for wood in ground contact or for other wet installations. Several formulations involving combinations of copper, chromium, and arsenic have shown high resis- tance to leaching and very good performance in service. The ammonia- cal copper arsenite and chromated copper arsenate are included in specifications for such items as building foundations, building poles, utility poles, marine piling, and piling for land and freshwater use. WOOD PRESERVATIVES 1047 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 Organic sulfones are another class of wood preservatives offering high degrees of protection. One such product is diiodomethyl p-tolyl sul- fone, with trade name Amical, from Angus Chemical Co. WOOL. The fine, soft, curly hair or fleece of the sheep, alpaca, vicuña, certain goats, and a few other animals. The specific designation wool always means the wool of sheep. Sheep’s wool is one of the most important commercial fibers because of its good physical qualities and its insulating value, especially for clothing, but it now constitutes only about 10% of the textile fiber market. It is best known for its use in clothing fabrics, called woolens. These are designated under a variety of very old general trade names such as a loosely woven fabric called flannel, or the fine, smooth fabric known as broadcloth. Cheviot is a close-napped, twill-woven fabric, and tweed is a woolen fabric with a coarse surface, usually with a herringbone-twill weave. Serge is a twill-woven worsted fabric. Worsteds are wool fabrics made from combed-wool yarn, usually from long, smooth wool. Wool is also employed for packings and for insulation, either loose or felted, and for making felts. The average amount of wool shorn from sheep in the United States is 8.1 lb (3.7 kg) per animal. Wool differs from hair in fineness and its felting and spinning prop- erties. The latter are due to the fine scales of the wool fibers. The finest short-staple wool has as many as 4,000 scales to the inch (2.5 cm), and the average long-staple wool has about 2,000 scales per inch (2.5 cm). These scales give wool its cohesive qualities. Some animals have both wool and hair, while others have wool only when young. There is no sharp dividing line between wool and hair. Wool quality is by fineness, softness, length, and scaliness. Fiber diameters vary from 0.0025 to 0.005 in (0.0064 to 0.013 cm). Long wools are generally heavy. Fibers below 3 in (7.6 cm) in length are known as clothing wool, and those from 3 to 7 in (7.6 to 17.8 cm) are called combing wools. Long wools are fibers longer than 7 in (17.8 cm). The term apparel wool generally means clothing wool of fine weaving quality from known sources. Fleece wool is the unscoured fiber. It may contain as much as 65% grease and dirt, but this is the form in which wool is normally shipped because it then has the pro- tection of the wool fat until it is manufactured. Wool is very absorbent to moisture and will take up about 33% of its weight of water, and in some areas moisture and dirty grease are added to fleece wool to increase weight. Carpet wools are usually long, nonresilient fibers from sheep bred in severe climates, such as the Mongolian wool. The only breed of sheep developed for wool alone is the merino. In Australia the corriedale and the polworth sheep are dual-purpose animals for wool and meat. 1048 WOOL 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 The finest of sheep wools come from the merino sheep, but these vary according to the age of breeding of the animal. The Lincoln sheep produces the longest fiber. It is lustrous but very coarse. Luster of wool depends upon the size and smoothness of the scales, but the chemical composition is important. The molecular chains are linked with sulfur, and when sulfur is fed to the sheep, in some defi- cient areas the quality of the wool is improved. Crimpiness in wool is due to the open formation of the scales. A fine merino will have 24 crimps per inch (2.5 cm), whereas a coarse crossbreed will have only 6 per inch (2.5 cm). Strength of wool fibers often depends upon the health of the animal and the feeding. One-quarter of the world production of wool is in Australia. Argentina ranks second in production, with the United States third. But the United States is a lamb-eating nation, and a large proportion of the animals are slaughtered when 4 to 8 months old, and most of the others are kept only one season for one crop of wool. New Zealand, Uruguay, Russia, and England are also important producers. England is the center of wool-sheep breeding, with more varieties than any other country. In general, warm climates produce fine wools, and hot climates produce thin, wiry wools, but the fundamental differences come from the type of animal and the feeding. The reused wool from old cloth was originally called shoddy, but the name has an opprobri- ous signification in the United States, and is not used by manufactur- ers to designate the fabrics made from reclaimed wool. Shoddy is used in mixtures with new wool for clothing and other fabrics. Extract wool is shoddy that is recovered by dissolving out the cotton fibers of the old cloth with sulfuric acid. Short fibers of shoddy, less than 0.5 in (1.27 cm), are known as mungo fibers. They are used in woolen blends to obtain a napped effect. Reprocessed wool is fiber obtained from waste fabric which has not been used. Noils are short fibers pro- duced in the combining of wool tops for making worsteds. They are used for woolen goods and felt. Zeset, of Du Pont, a shrinkproofing agent for wools, is a variant of Surlyn T, a terpolymer of 70% ethyl- ene, 6 methacryloyl chloride, and 24 vinyl acetate. It prevents shrink- age and pilling under ordinary laundry methods, does not affect color, and increases the tensile strength of the fiber. But all resinous addi- tives tend to harden the fiber and lessen the drape and feel. Conversely, each dry cleaning of wool fabric decreases the natural oil content and hardens the fiber. WOOL GREASE. A brownish, waxy fat of a faint, disagreeable odor, obtained as a by-product in the scouring of wool. The purified grease was formerly known as degras and was used for leather dressing, in lubricating and slushing oils, and in soaps and ointments; but it is now WOOL GREASE 1049 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 [...]... blades are Y-TZP and can be used when the delicate taste of raw fish would be tainted by slicing with metal-blade knives Tungsten-carbide-reinforced Y-TZP, developed by Toray Industries and Nippon Tungsten Co of Japan, has five times the thermal conductivity of Y-TZP and high hardness, strength, toughness, and heat resistance Magnesia-stabilized PSZ, Mg-PSZ, is fired at a higher temperature than Y-TZP and,... more creep-resistant at room and elevated temperatures The most recent casting alloys are three high-aluminum zinc casting alloys for sand and permanent-mold casting: ZA-8, ZA-12, and ZA-27, the numerals in the designations indicating approximate aluminum content They also contain more copper than AG40A and AC41A, from 0.5 to 1.2% in ZA-12 to 2 to 2.5 in ZA-27, and a bit less magnesium As sand-cast, ultimate... website Materials, Their Properties and Uses 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 Source: Materials Handbook Part 2 Structure and Properties of Materials Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)... for wood, and railway crossties treated with the material were called Burnettized wood But it is highly soluble and leaches out of the wood, and is now chromated and copperized with sodium bichromate and cupric chloride Copperized CZC, of Koppers Co., Inc., for treating wood against rot and termites, is copperized chromated zinc chloride zinc chloride is also used for vulcanizing fiber, as a mordant,... must be stabilized or partially stabilized to prevent a monoclinic-tetragonal phase change Stabilization involves the addition of calcia, magnesia, or yttria followed 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... substituted Merchant bar iron is an old name for wrought-iron bars and rods made by faggoting and forging Iron-fibered steel is soft steel with fine iron wire worked into it Staybolt iron may be wrought iron, but was originally puddled charcoal iron Lewis iron, for staybolts, is highly Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill... vapor, which has limited Y-TZP to moisturefree valve applications Another zirconia ceramic–developed material is zirconia-toughened alumina (ZTA) ZTA zirconia is a composite polycrystalline ceramic containing ZrO2 as a dispersed phase (typically about 15 volume %) Close control of initial starting-powder sizes and sintering schedules is thus necessary in order to attain the desired ZrO2 particle dimensions... acetylated lanolin is hydrophobic and oil-soluble, and is used as an odorless, nontacky emollient in cosmetics Acylan, from Croda Chemicals, is a soft solid with a bland odor that is employed in baby products, hair grooms, creams, and pharma- Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any... MATTER 1071 ments, expelling the detached electrons, and when captured are deposited as helium These usually come from outer-ring spherons and not necessarily from the inner nucleus The expelled electrons are beta rays When these collide with a nucleus, high-frequency X-rays break off Gamma rays are emitted from some radioactive elements The difference between X-rays and gamma rays is their origin and... 40.08 12.00 140 .13 132.91 35.457 52.01 58.94 92.91 63.57 162.46 167.64 152.0 19.00 223 157.3 69.72 72.60 197.2 178.6 4.002 163.5 1.0078 147 .0 114. 76 126.92 192.9 55.84 83.7 138.92 207.22 6.940 175.0 Melting point, °C 143 0 660.0 630.5 Ϫ189.3 814 470 704 1280 271.3 2300 Ϫ7.2 320.9 850 3700 798 28 Ϫ101 1800 149 0 2000 1083.0 141 2 1529 822 Ϫ223 …… 1312 29.78 958 1063.0 1700 Ϫ271.4 147 4 Ϫ259.2 156.4 114 2447 . the zinc-air battery, which, for powering electric vehi- 1054 ZINC Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill. between the outside wood with narrow rings and the wide- ringed wood of the interior. Heartwood is the dark center of the tree which has become set, and through which the sap has ceased to flow. Sapwood. Since the zinc alloys can be cast easily in high-speed machines, producing parts that weigh less than brass and have high accuracy and smooth surfaces that require minimum machining and finishing,