Energy values small radii

In general, the smallest values for and / are desirable. Based on (11), the two major variables that determine Rq are p/q and d/a-e, each of which should be small. Small resistivity and large heat transfer flux are obviously advantageous nevertheless, the most adjustable parameter is d/ae. For this reason, the conductor of an energy storage magnet is rippled to obtain a small radius of curvature a. 

We should remember that the principle that leads to Eq. 24.1 assumes that there is only one value of the surface energy the surface energy is assumed to be isotropic. When the particle size of the powder is small, the powder has a large surface area in comparison with a similar volume of bulk solid. We can say that a small particle, which is assumed to be a sphere, has surface properties that are different from those of a bulk solid because it has a large surface-to-volume ratio and because its surface has a small radius of curvature. 

A small radius of curvature in the fiber-fiber contact areas results in cohesive forces of a very small magnitude. This necessitates the use of highly precise methods and devices for measuring these small forces in contacts between individual fibers, under both normal rupture and shear. Such measurements provide one with the means for the evaluation of a contribution of molecular attraction to friction forces and allow one to obtain a thermodynamic value of the free energy of interaction. The latter is a general characteristic of interactions in a given medium, invariant with respect to the specimen geometry. 

We list in Table 11 the Gibbs free energies for hydration (35) AG° and hydration numbers n for the alkali metal cations (the values for n are a combination of experimental determinations (17,36,37) and of personal choice between conflicting results ). Just like the gas-phase value (Table 8, for instance) the AG° values vary regularly with the ionic radius, the smallest ions being more strongly hydrated. Lithium ion owes to its very small radius an unusually small coordination sphere, consisting of only four water molecules in the primary hydration shell (37). 

The strain energies of these five-membered heterocycles are relatively small with values of 23.5, 24.8 and S.SkJmoF estimated for tetrahydrofuran, pyrrolidine and tetrahy-drothiophene respectively (74PMH(6)199). The closeness of the values for the two former compounds reflects the almost identical covalent radii of oxygen (0.66 A) and nitrogen (0.70 A) atoms. The sulfur atom with a much larger covalent radius of 1.04 A causes a... 

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