Cavity curvature

Figure 2.2 Bubble activation (a) change of radius of curvature of a bubble as it grows out from a cavity (b) criterion for activation of ebullition site. (From Hsu and Graham, 1976. Copyright 1976 by Hemisphere Publishing Corp., New York. Reprinted with permission.)...

Equation (2-14) provides a way to calculate the liquid temperature in equilibrium with the ready-to-grow bubble if the saturation pressure or temperature, the value of B, and the cavity radius are known (Shai, 1967). Several modified versions of nucleation criteria have since been advanced. An example is the model proposed by Lorenta et al. (1974), which takes into account both the geometric shape of the cavity and the wettability of the surface (in terms of contact angle < >). Consider an idealized conical cavity with apex angle ip, and a liquid with a flat front penetrating into it (Fig. 2.3a). Assume that once the vapor is trapped in by the liquid front, the interface readjusts to form a cap with radius of curvature rn. Conservation of vapor... 

Usually, the zeolite inner surface characteristics are rather complex as a consequence of the (3D) character of the porous topologies of most of the zeolite types. The porous framework is a (3D) organization of cavities connected by channels. Inner surfaces are composed of several sorption sites characterized by their local geometry and curvature. Illustrative examples of such inner surface complexity are represented on Figures 1 and 2 they concern the Faujasite and Silicalite-I inner surfaces respectively. 

The main difference between carbon nanotubes and high surface area graphite is the curvature of the graphene sheets and the cavity inside the tube. In microporous solids with capillaries which have a width not exceeding a few molecular diameters, the potential fields from opposite walls will overlap so that the attractive force which acts upon adsorbate molecules will be increased in comparison with that on a flat carbon surface [16]. This phenomenon is the main motivation for the investigation of the interaction of hydrogen with carbon nanotubes (Figure 5.14). 

This is for a spherical cavity. For a cavity with two principle radii of curvature, rx and r2, Eq. (21) becomes3... 

The experimental arrangement is basically similar to that of Hansch et al. (4). A Spectra Physics Ar+ laser operating at 514.5 nm pumps a Rhodamine 6G dye laser tuned with a birefrin-gent filter. The linewidth is 25 to 30 GHz, and the wavelength is tuned between 585.0 nm and 585.2 nm. The output mirror has a 1 meter radius of curvature and a reflectivity of 98% at 585.0 nm. The dye laser cavity is 74 cm long, and the laser is always run TEMoo (this sometimes necessitates the use of an intracavity aperture). 

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