Marbles

Limestone varieties differ greatly from one another in their texture and the impurities they contain, and consequently they also differ in color. The color of limestone may vary from white (when it contains practically no impurities) to off-white and even to intensely colored. Minor inclusions within the limestone structure are often of silica, usually in a concentration below 5%, as well as feldspar and clay in still lesser amounts. Many types of limestone also include embedded fossils. Much limestone deposits in the outer crust of the earth are altered during geologic metamorphic processes that involve mainly pressure and heat but also liquids and gases. Marble, for example, a metamorphic rock derived from calcium carbonate, is white when composed only of this substance colored metal ions and other impurities impart to marble a wide range of colors such as red, yellow, and green and also give 

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In classical mechanics, it is certainly possible for a system subject to dissipative forces such as friction to come to rest. For example, a marble rolling in a parabola lined with sandpaper will eventually lose its kinetic energy and come to rest at the bottom. Rather remarkably, making a measurement of E that coincides with... 

Before use, the marble chips are washed repeatedly with hot water, and then de-aerated by first etching them with concentrated hydrochloric acid and then boiling them with air-free water under reduced pressure. The chips are then rapidly transferred to the generator small chips should be used and the bulb... 

The relatively concentrated hydrochloric acid is employed so that with ordinary use of the apparatus, spent liquor does not accumulate very rapidly the concentrated acid also ensures a brisk and delicately controlled flow of gas. When the generator is replenished with acid, marble or both, the de-aeration procedure detailed above is repeated until a sufficiently air-free gas supply is obtained. 

Carbon dioxide. This gas is conveniently generated from marble and dilute hydrochloric acid (1 1) in a Kipp s apparatus it should be passed through a wash bottle containing water or sodium bicarbonate solution to remove acid spray and, if required dry, through two further wash bottles charged with concentrated sulphuric acid. 

Marble polishing Marble simulation Marcaine Marcasite... 

Synthetic lubricants Synthetic marble Synthetic membranes Synthetic methanol Synthetic musk Synthetic natural gas... 

Fats can be an important source of lubrication in the preparation and consumption of foods (30). Marble slabs on which hot candy is poured are lubricated with fat to prevent sticking. Also, bread and cake pans are treated with heatstable edible oil. 

Similarly, those proteins can be combined with uncolored ingredients to imitate marbling and form pet foods with chunk-meat appearance. This processing is commonly used in semimoist pet foods. 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

Although the use of simple diluents and adulterants almost certainly predates recorded history, the use of fillers to modify the properties of a composition can be traced as far back as eady Roman times, when artisans used ground marble in lime plaster, frescoes, and po22olanic mortar. The use of fillers in paper and paper coatings made its appearance in the mid-nineteenth century. Functional fillers, which introduce new properties into a composition rather than modify pre-existing properties, were commercially developed eady in the twentieth century when Goodrich added carbon black to mbber and Baekeland formulated phenol— formaldehyde plastics with wood dour. 

When a question exists about whether the carving is ancient, an examination under uv illumination can be very helpful. For example, an aged marble surface exhibits, under a properly filtered mercury lamp, a mellow, brownish fluorescence, whereas a fresh surface, under the same conditions, appears purple. It is not uncommon that old carvings have been sharpened this is detectable with the microscope and under uv examination. 

For marble provenance studies, the most successful technique seems to be the measurement, through mass spectrometry, of the abundance ratios of the stable isotopes of carbon and oxygen (116). However, no single technique appears to provide unequivocal results, especially in cases such as the different Mediterranean sources, and a combination is often necessary to arrive at an approximate place of origin (117). 

Marble. Art Historical and Scientific Perspectives on Ancient Sculpture, The J. Paul Getty Museum, MaHbu, Calif., 1990. 

N. Her2 and M. Waelkens, ed.. Classical Marble Geochemisty, Technology andTrade, Vol. 153, NATO Advanced Science Institute, Series E AppHed Sciences, Kluwer, Dordrecht, 1988. 

Manufacturers of alumina trihydtate include Solem Industries, Aluchem, Alcoa, Custom Grinding Sales, R. J. Marshall, Georgia Marble, and Hitax. 

The weatherabihty and hydrolytic stabiUty of unsaturated polyesters based on neopentyl glycol have made it a popular intermediate for use in formulations exposed to severe conditions, eg, in gel coats for cultured marble and marine appHcations (see Coatings, marine) (13). 

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