Large -scale

Usually prepared on the large scale by caustic soda fusion of sodium naphthalene-1-sulphonate, but can also be obtained by high-temperature alkaline digestion of... 

The features created by crustal movements may be mountain chains, like the Himalayas, where collision of continents causes extensive compression. Conversely, the depressions of the Red Sea and East African Rift Basin are formed by extensional plate movements. Both type of movements form large scale depressions into which sediments from the surrounding elevated areas ( highs ) are transported. These depressions are termed sedimentary basins (Fig. 2.3). The basin fill can attain a thickness of several kilometres. 

Both survey methods are mainly employed to define large scale structures such as basins. Based on the resulting maps, seismic surveys are then carried out. 

A karst structure . e. a limestone formation which has been eroded resulting in a large scale, open system comparable to a cave... 

Deimis,J.J. and Woods,D.J., New Computing Environments Microcomputers in Large-Scale Computing, SIAM, New York, pp. 116-122, 1987... 

A very important but rather complex application of surface chemistry is to the separation of various types of solid particles from each other by what is known as flotation. The general method is of enormous importance to the mining industry it permits large-scale and economic processing of crushed ores whereby the desired mineral is separated from the gangue or non-mineral-containing material. Originally applied only to certain sulfide and oxide ores. 

Figure Al.7.2. Large-scale (5000 Atimes 5000 A) scanning tiimielling microscope image of a stepped Si (111)-(7 X 7) surface showing flat terraces separated by step edges (courtesy of Alison Baski).

Gain G 2000 Large-scale electronic structure calculations using linear scaling methods Status Solidi B 217 231... 

Iterative approaches, including time-dependent methods, are especially successfiil for very large-scale calculations because they generally involve the action of a very localized operator (the Hamiltonian) on a fiinction defined on a grid. The effort increases relatively mildly with the problem size, since it is proportional to the number of points used to describe the wavefiinction (and not to the cube of the number of basis sets, as is the case for methods involving matrix diagonalization). Present computational power allows calculations... 

Roos B 1972 A new method for large-scale Cl calculations Chem. Phys. Lett. 15 153... 

An important step in tire progress of colloid science was tire development of monodisperse polymer latex suspensions in tire 1950s. These are prepared by emulsion polymerization, which is nowadays also carried out industrially on a large scale for many different polymers. Perhaps tire best-studied colloidal model system is tliat of polystyrene (PS) latex [9]. This is prepared with a hydrophilic group (such as sulphate) at tire end of each molecule. In water tliis produces well defined spheres witli a number of end groups at tire surface, which (partly) ionize to... 

The relations pertain to the fine, small-scale time variations in the phase and the log modulus, not to their large-scale changes. 

Worth and Cederbaum [100], propose to facilitate the search for finding a conical intersection if the two states have different symmetiies If they cross along a totally symmetric nuclear coordinate, then the crossing point is a conical intersection. Even this simplifying criterion leaves open a large number of possibilities in any real system. Therefore, Worth and Cederbaum base their search on large scale nuclear motions that have been identified experimentally to be important in the evolution of the system after photoexcitation. 

Large-scale methods of producing hydrogen are considered in a later chapter... 

The hydroxides M (OH)2 are generally less soluble and are of lower base strength. The Group I hydroxides are almost unique in possessing good solubility—most metal hydroxides are insoluble or sparingly soluble hence sodium hydroxide and, to a lesser extent potassium hydroxide, are widely used as sources of the hydroxide ion OH" both in the laboratory and on a large scale. 

Aluminium is obtained on a large scale by the electrolysis of the oxide, dissolved in fused cryolite The oxide, occurring naturally as bauxite, AI2O3.2H2O, usually contains silica and iron(III) oxide as impurities. These must be removed first, since aluminium, once prepared, cannot be freed of other metals (which will be deposited on electrolysis) by refining it. The crude oxide is dissolved under pressure in caustic soda solution the aluminium oxide and silica dissolve and the ironflll) oxide is left ... 

On the large scale, nitric acid is now made in large quantities by the catalytic oxidation of ammonia, employing the reaction ... 

By boiling, as explained above a method too expensive for use on a large scale. 

On a large scale, hydrogen peroxide is produced by the electrolysis of ammonium hydrogensulphate, using a platinum anode and a lead cathode separated by a diaphragm. The essential process occurring is ... 

On a large scale chlorine is obtained in several ways. 

This reaction is also used on a large scale, to obtain iodine from seaweed. The ash from burnt seaweed ( kelp ) is extracted with water, concentrated, and the salts other than iodides (sulphates and chlorides) crystallise out. The more soluble iodides remain and the liquor is mixed with sulphuric acid and manganese dioxide added the evolved iodine distils off and is condensed. 

Hydrogen fluoride is the most important compound of fluorine. It is prepared in the laboratory, and on the large scale, by the reaction of calcium fluoride with concentrated sulphuric acid. ... 

Electrolysis of hydrochloric acid yields hydrogen at the cathode and oxygen at the anode from the dilute acid, but chlorine at the anode (of carbon) from the concentrated acid. Electrolysis of the concentrated acid is used on the large scale to recover chlorine. 

Sodium dichromate is prepared on the large scale by heating powdered chromite with sodium carbonate, with free access of air the sodium chromate first formed is treated with acid ... 

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