Mixing tendency toward

Complexes (191) and (192) are formed from dimethyldiazirine with carbonyls of chromium, molybdenum and tungsten. They show no tendency towards N—N cleavage (80JOM(193)57). Complex (193) is made from a mixed complex by displacement of norbor-nadiene. 

Consider two reactions for which ° shows that products are favored, one an exothermic reaction, and the other an endothermic reaction. For the exothermic reaction, when the reactants are mixed they are driven toward equilibrium in accord with the tendency toward minimum energy. Now contrast the endothermic reaction for which ° shows that equilibrium favors products. When these reactants are mixed, they approach equilibrium against the tendency toward minimum energy (since heat is absorbed). This reaction is driven by the tendency toward maximum randomness. 

The resultant material in many cases is not flowable , which means it tends to cake or agglomerate. It is then difficult to get good partide distribution which increases the tendency toward heterogeneity and means mixing of the material before sampling is critical. 

Disordered alloys may form when two metals are mixed if both have body-centered cubic structures and if their atomic radii do not differ by much (e.g. K and Rb). The formation of ordered alloys, however, is usually favored at higher temperatures the tendency towards disordered structures increases. Such an arrangement can even be adopted if metals are combined which do not crystallize with body-centered cubic packings themselves, on condition of the appropriate composition. /J-Brass (CuZn) is an example below 300 °C it has a CsCl structure, but between 300 °C and 500 °C a A type transformation takes place resulting in a disordered alloy with a body-centered cubic structure. 

Most particles acquire a surface electric charge when in contact with a polar medium. Ions of opposite charge (counter-ions) in the medium are attracted towards the surface and ions of like charge (co-ions) are repelled, and this process, together with the mixing tendency due to thermal motion, results in the creation of an electrical double-layer which comprises the charged surface and a neutralising excess of counter-ions over co-ions distributed in... 

Where the maintenance of a clear channel between sprue and the slowest freezing part of a charge is impractical, cavitation is avoided by casting charges in layers, each of which is allowed to crust over before pouring the next TNT melts at 81°. It forms eutectics with RDX, Tetryl (68°), PETN (76°), and other impurities in the mix and makes these materials more soluble at higher temps. Thus, there is a general tendency for the solid content and, hence, the apparent viscosity of most castable mixts to decrease as the temp is increased. However, a reversal of the tendency toward the reduction in viscosity has been noted in Comp B when it heated above 100°... 

The extent of reversibility of complexation depends mainly on the aqueous environment and the mixing conditions (Tolstoguzov, 1986 Galazka et al, 1999). The tendency towards non-equilibrium formation of an insoluble coacervate is enhanced at low ionic strength and at pH values significantly below the p/ of the protein. 

Finally, we note here that the dehydration of biopolymers associated with their attractive non-ionic interactions (dipole-dipole, hydrophobic) can increase the contribution of the mixing entropy. This in turn can lead to a tendency towards enhancement of the thermodynamically favourable interactions between them (Appelqvist and Debet, 1997 Cai and Arnt-field, 1997 Semenova a/., 1991b). 

Qualitatively, such positive deviations can be associated with phobicity between components (i.e., solute and solvent that are unhappy to mix ), corresponding to a tendency toward immiscibility. At the molecular level, this tendency is associated with like-molecule solute-solute or solvent-solvent interactions that are stronger than the corresponding solute-solvent interactions in solution, i.e.,... 

The mixed acid used in the nitration of cellulose has a compn dependent upon the type of cellulose nitrated, the degree of nitration desired, and the season of the year. During warm weather, it is necessary that the HN03 content be si greater than during winter, because of a tendency toward denitration of the mixed acid during warm weather. Variations in mixed... 

The strong adsorption of such materials at surfaces or interfaces in the form of an orientated monomolecular layer (or monolayer) is termed surface activity. Surface-active materials (or surfactants) consist of molecules containing both polar and non-polar parts (amphiphilic). Surface activity is a dynamic phenomenon, since the final state of a surface or interface represents a balance between this tendency towards adsorption and the tendency towards complete mixing due to the thermal motion of the molecules. 

A more expensive alternative is to use standard AutoAnalyser type systems, based on multichannel peristaltic pumps, to pump samples and reagents and/or diluents at the desired rates to give automatic mixing at the desired ratio. Flame photometric detectors have been used for many years with AutoAnalysers, especially in clinical laboratories. Curiously, in the past, this approach has less often been routinely used in environmental analytical laboratories employing flame spectrometry, perhaps because an attractive feature of flame spectrometry is the speed of response when used conventionally. Over the past few years, however, there has been an increasing tendency towards fully automated, unattended operation of flame spectrometers. This undoubtedly reflects, at least in part, the improvements in safety features in modern instruments, which often incorporate a comprehensive selection of fail-safe devices. It also reflects the impact of microprocessor control systems, which have greatly facilitated automation of periodic recalibration. 

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