Character definition

P.M. de Wolff, B. Gruber, Niggli lattice characters Definition and graphical representation, Acta Cryst. A47,29 (1991)... 

In most organometallic compounds the M —C bond has, to a significant degree, covalent character. Definite ionic character of this bond is generally manifested only in compounds of the alkali and alkaline earth metals. The ionic or covalent contribution to the bond depends on ionization potential of the metal, the size of a resulting ion, the ratio of the ionic charge to its radius, and tr-donor, (j-acceptor, 7c-donor, and 7c-acceptor properties of ligands and their structure. 

A flavor contributory item is an additive that when smelled and/or tasted helps to create, enhance, or potentiate the named flavor. It is not characteristic of the flavor, but essential in that it acts with other substances to produce a definite character. 

Sediment. The sediment test consists of filtering a definite quantity of milk through a white cotton sediment test disk and observing the character and amount of residue. Efficient use of single-service strainers on dairy farms has reduced the use of sediment tests on milk as deflvered to receiving plants. Although the presence of sediment in milk indicates unsanitary production or handling, its absence does not prove that sanitary conditions always existed. 

No single method or algorithm of optimization exists that can be apphed efficiently to all problems. The method chosen for any particular case will depend primarily on (I) the character of the objective function, (2) the nature of the constraints, and (3) the number of independent and dependent variables. Table 8-6 summarizes the six general steps for the analysis and solution of optimization problems (Edgar and Himmelblau, Optimization of Chemical Processes, McGraw-HiU, New York, 1988). You do not have to follow the cited order exac tly, but vou should cover all of the steps eventually. Shortcuts in the procedure are allowable, and the easy steps can be performed first. Steps I, 2, and 3 deal with the mathematical definition of the problem ideutificatiou of variables and specification of the objective function and statement of the constraints. If the process to be optimized is very complex, it may be necessaiy to reformulate the problem so that it can be solved with reasonable effort. Later in this section, we discuss the development of mathematical models for the process and the objec tive function (the economic model). 

The indolinol character of eseretholemethine is indicated by the fact that the methiodide on treatment with picric acid yields a diquaternary pierate (m.p. 170°) with the loss of the hydroxyl group. More definite proof is afforded by the oxidation of eseretholemethine with ammoniaeal silver nitrate or potassium ferricyanide, when a dehydroeseretholemethine (oxyeseretholemethine of Polonovski), pierate, m.p. 199°, is produced which is assumed to have formula (VI), since on exhaustive methylation it yields trimethylamine and an unsaturated product (deep-red pierate, m.p. 103°), which absorbs two atoms of hydrogen, forming 5-ethoxy-l 8-dimethyl-S-ethyl-2-indolinone (VII), colourless cubes, m.p. 68°. The... 

On the basis of the reaction of alkyl radicals with a number of polycyclic aromatics, Szwarc and Binks calculated the relative selectivities of several radicals methyl, 1 (by definition) ethyl, 1.0 n-propyl, 1.0 trichloromethyl, 1.8. The relative reactivities of the three alkyl radicals toward aromatics therefore appears to be the same. On the other hand, quinoline (the only heterocyclic compound so far examined in reactions with alkyl radicals other than methyl) shows a steady increase in its reactivity toward methyl, ethyl, and n-propyl radicals. This would suggest that the nucleophilic character of the alkyl radicals increases in the order Me < Et < n-Pr, and that the selectivity of the radical as defined by Szwarc is not necessarily a measure of its polar character. 

Firpene is a terpene, which may be a chemical individual, but which may be an impure terpene not yet definitely characterised. It was isolated from the turpentine of the Western fir, by Frankforter and Frary, who found it to have the following physical characters —... 

What is an engineering standard Webster s New International Dictionary contains the following definition Standard That which is established by authority, custom, or general consent, as a model or example, criteria, text. In general, a definitive level, degree, material, character, quality, or the like, viewed as that which is proper and adequate for a given purpose. 

However, serious difficulties appeared later when efforts were made to attack more general problems not necessarily of the nearly-linear character. In terms of the van der Pol equation this occurs when the parameter is not small. Here the progress was far more difficult and the results less definite moreover there appeared two distinct theories, one of which was formulated by physicists along the lines of the theory of shocks in mechanics, and the other which was analytical and involved the use of the asymptotic expansions (Part IV of this chapter). The latter, however, turned out to be too complicated for practical purposes, and has not been extended sufficiently to be of general usefulness. 

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