Tensioning: advantages

We noted in Section VII-2B that, given the set of surface tension values for various crystal planes, the Wulff theorem allowed the construction of fhe equilibrium or minimum firee energy shape. This concept may be applied in reverse small crystals will gradually take on their equilibrium shape upon annealing near their melting point and likewise, small air pockets in a crystal will form equilibrium-shaped voids. The latter phenomenon offers the possible advantage that adventitious contamination of the solid-air interface is less likely. 

The choice of the solvent also has a profound influence on the observed sonochemistry. The effect of vapor pressure has already been mentioned. Other Hquid properties, such as surface tension and viscosity, wiU alter the threshold of cavitation, but this is generaUy a minor concern. The chemical reactivity of the solvent is often much more important. No solvent is inert under the high temperature conditions of cavitation (50). One may minimize this problem, however, by using robust solvents that have low vapor pressures so as to minimize their concentration in the vapor phase of the cavitation event. Alternatively, one may wish to take advantage of such secondary reactions, for example, by using halocarbons for sonochemical halogenations. With ultrasonic irradiations in water, the observed aqueous sonochemistry is dominated by secondary reactions of OH- and H- formed from the sonolysis of water vapor in the cavitation zone (51—53). 

As the production methods of MWCNTs is very efficient [8] (see Chaps. 2 and 12), it is an advantage to implement a filling procedure after the synthesis. A promising approach to fill CNT cavities, could exploit the capillary properties that have been revealed by Ajayan and lijima [9]. Subsequent studies by Dujardin et al.[10] allowed the estimations of a surface tension threshold in order to select materials that are good candidates to wet and fill CNTs. 

For a situation where large torques are involved, such as a bicycle drive, a chain linkage is superior to a belt. A person putting all his or her weight on a pedal probably would make most belt systems slip. Another advantage of a chain over a belt is that a chain is more efficient, mainly because it does not require any ambient tension. The return side of a chain drive has only enongh tension to snpport itself. Furthermore, the chain links are equipped with rollers, which can rotate as they contact the teeth, reducing the frictional forces and wear. 

CMCs of LAS-AOS mixtures in water that contained no calcium or magnesium ions were determined by Suri et al. [3] by means of the surface tension method. The purpose of this work was to study the advantage of LAS-AOS synergism in prototype phosphate-free carbonate-built formulations for use in the Indian market. The authors have used a commercial C10-C14 LAS sample with an average molecular weight of 343 and a commercial C16-C18 AOS sample with an average molecular weight of 350. 

In the case of epoxide cements at temperatures lower than 20° C, the viscosity increases so much that pumping becomes difficult [342]. Small amounts of aromatic solvents reduce the viscosity satisfactorily. Ethylene glycol butyl ether also changes the interfacial tension so that the polymer may penetrate into hairline cracks and fine capillaries. This is advantageous in blocking liquid or gas migration. 

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