- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A material added to paint formulations to facilitate the oxidation of oils. Linseed oil in its pure state normally requires about 3 days to dry to a hard film; linseed oil with driers added dries to a hard film in about 4 h.
Industry:Science
A material capable of fastening together two other materials by means of surface attachment. The terms glue, mucilage, mastic, and cement are synonymous with adhesive. In a generic sense, an adhesive is any material capable of fastening by means of surface attachment, and thus includes inorganic materials such as portland cement and solder. Practically, however, adhesives are a broad set of materials composed of organic, primarily polymeric materials that can be used to fasten two other materials together. The materials being fastened are often called adherends, and the resulting assembly is called an adhesive joint or adhesive bond.
Industry:Science
A material composed of gas bubbles separated from one another by liquid or solid sheets (or lamellae). Foam densities range from nearly zero to about 43 lb/ft<sup>3</sup> (0.7 g/cm<sup>3</sup>), above which gas emulsions rather than foams are formed. The bubbles are spherical when the lamellae that separate the bubbles are thick (approximately 0.04 in. or 1 mm); the bubbles are polyhedral when the lamellae are thin (approximately 0.0004 in. or 0.01 mm). Pure liquids do not foam; that is, they cannot produce liquid lamellae of any permanence. Relatively permanent lamellae are created only when a substance is present that is adsorbed at the surface of the liquid. Such substances may be in true solution in the liquid, or they may be particles of a finely divided solid which, because of poor wetting by the liquid, remain at the surface. In both cases, surface layers rich in the added substance are formed. The inability of the adsorbed substance to enter the bulk of the liquid preserves the surface and so confers stability on the foam lamellae. However, this stability is transient. Gravity drains solution out of the lamellae, and the solubility of gas in the solution, although slight, allows gas to diffuse out of the foam. These destabilizing factors tend to separate the liquid and the gas phases of the foam and so destroy it.
Industry:Science
A material in which a continuous metallic phase (the matrix) is combined with another phase (the reinforcement) that constitutes a few percent to around 50% of the material's total volume. In the strictest sense, metal matrix composite materials are not produced by conventional alloying. This feature differentiates most metal matrix composites from many other multiphase metallic materials, such as pearlitic steels or hypereutectic aluminum-silicon alloys.
Industry:Science
A material in which one spatial dimension, thickness, is much smaller than the other two. Films can be conveniently classified as those that support themselves and those that exist only as layers on top of a supporting substrate. The latter are known as thin films and have their own specialized science and technology.
Industry:Science
A material made mainly of natural or synthetic fibers. Modern textile products may be prepared from a number of combinations of fibers, yarns, films, sheets, foams, furs, or leather. They are found in apparel, household and commercial furnishings, vehicles, and industrial products. Materials made solely from plastic sheet or film, leather, fur, or metal are not usually considered to be textiles.
Industry:Science
A material of extreme hardness that is used to shape other materials by a grinding or abrading action. Abrasive materials may be used either as loose grains, as grinding wheels, or as coatings on cloth or paper. They may be formed into ceramic cutting tools that are used for machining metal in the same way that ordinary machine tools are used. Because of their superior hardness and refractory properties, they have advantages in speed of operation, depth of cut, and smoothness of finish.
Industry:Science
A material processing method which utilizes the high power density available from focused laser sources to melt metal coatings and a portion of the underlying substrate. Since the melting occurs in a very short time and only at the surface, the bulk of the material remains cool, thus serving as an intimate heat sink. Large temperature gradients exist across the boundary between the melted surface region and the underlying solid substrate. The result is rapid self-quenching and resolidification.
Industry:Science
A material structure assembled from a layer or cluster of atoms with size of the order of nanometers. Interest in the physics of condensed matter at size scales larger than that of atoms and smaller than that of bulk solids (mesoscopic physics) has grown rapidly since the 1970s, owing to the increasing realization that the properties of these mesoscopic atomic ensembles are different from those of conventional solids. As a consequence, interest in artificially assembling materials from nanometer-sized building blocks, whether layers or clusters of atoms, arose from discoveries that by controlling the sizes in the range of 1–100 nm and the assembly of such constituents it was possible to begin to alter and prescribe the properties of the assembled nanostructures. (Many examples of naturally formed nanostructures can be found in biological systems, from sea shells to the human body.)
Industry:Science
A material system composed of a mixture or combination of two or more macroconstituents that differ in form or material composition and are essentially insoluble in each other. This definition is considered to be too broad by some engineers because it includes many materials that are not usually thought of as composites. For example, in many of the particulate-type composites, such as dispersion-hardened alloys and cermets, the composite structure is microscopic rather than macroscopic. Also, this definition does not draw the line between composite materials and composite structures. However, instead of trying to establish a distinction between materials and structures, it is more useful to make a distinction between mill composites (such as nonmetallic laminates, clad metals, and honeycomb) and specialty composites (such as tires, rocket nose cones, and glass-reinforced plastic boats).
Industry:Science
