Penetration effects

First, the eddy current density is damped while penetrating into the conductor (penetration effect). Here the frequency dependence of the penetration depth implies that for deep lying cracks low frequencies must be used for obtaining a sufficient current density in the vicinity of the crack. Secondly, due to the induction law the induced current density at the surface jco is diminished when using lower frequencies. Therefore, in total, there is a certain excitation frequency which results in a maximum response field from the crack. 

Type V isotherms of water on carbon display a considerable variety of detail, as may be gathered from the representative examples collected in Fig. 5.14. Hysteresis is invariably present, but in some cases there are well defined loops (Fig. 5.14(b). (t ), (capillary-condensed water. Extreme low-pressure hysteresis, as in Fig. 5.14(c) is very probably due to penetration effects of the kind discussed in Chapter 4. 

This cieam also contains zinc naphthenate, terpineol, chloiciesol, and methyl salicylate [119-36-8J.S The latter has a deeply penetrative effect. It combines... 

Pellets, slugs or flechettes made of U have very good powers of penetration. However, U is softer than steel so that in the process of penetrating an armored steel plate it is partially pulverized. Since in this form U is pyrophoric (self-igniting), such projectiles have an incendiary as well as a penetrating effect. According to one account of flechettes made of depleted U ... 

As the SIBFA approach relies on the use of distributed multipoles and on approximation derived form localized MOs, it is possible to generalize the philosophy to a direct use of electron density. That way, the Gaussian electrostatic model (GEM) [2, 14-16] relies on ab initio-derived fragment electron densities to compute the components of the total interaction energy. It offers the possibility of a continuous electrostatic model going from distributed multipoles to densities and allows a direct inclusion of short-range quantum effects such as overlap and penetration effects in the molecular mechanics energies. 

Jurinak, J.J. (1966) Surface chemistry of hematite Anion penetration effect on water adsorption. Soil Sci. Soc. Am. Proc. 30 559-562... 

When diesel fuel is injected into the high-pressure environment of a combustion chamber, it must fully penetrate into the pressurized air in order to completely combust. Fuel with a low viscosity does not have enough thrust to penetrate effectively through the pressurized air and disperse completely. The result is a soft, nonpenetrating spray which does not spread throughout the chamber. Poor combustion efficiency and engine power result. 

The early the rinsing, the least need to counter the penetration effect. 

A few years after the discovery that the treating of cellulose with nitric acid converts it into a combustible substance, the idea arose of using nitrocellulose as a propellant instead of blackpowder. Schonbein s experiments [1], repeated by Pelouze [2], showed the high energy of nitrocellulose. It was found that a charge of nitrocellulose endows a projectile with a penetrating effect similar to that of a triple charge of blackpowder. 

It is also possible to visualize, in a qualitative way, that this penetration effect alone will lead to a non-linear molecule. Let us suppose that we put three positive charges in a sphere uniformly filled with negative charges. The three charges will be attracted to the centre of the sphere and at the same time will repel one another. 

Another type of interaction is the penetration of a surface-active constituent of the substrate into a spread monolayer. Penetration effects can be studied by injecting a solution of the surface-active material into the substrate immediately beneath the monolayer a) if there is no association between the injected material and the monolayer, tt and AK will both remain unaltered (b) if the injected material adsorbs on to the underside of the monolayer without actual penetration, AK will change appreciably but tt will alter very little (c) if the injected material penetrates into the monolayer (i.e. when there is association between both polar and non-polar parts of the injected and original monolayer materials), ir will change significantly and A V will assume an intermediate value between AV of the original monolayer and AV of a monolayer of injected material. Penetration is less likely to occur when the monolayer is tightly packed. 

In the NDDO scheme, two-center contributions involve also the penetration effects defined in [56] as the difference between the potential induced on the AOs of the atom M by the nucleus of atom K and by the electron distribution around atom K. The corresponding integrals are taken to be proportional to two-center Coulomb integrals ... 

Cossi, M., Rega N., Scalmani G. and Barone V., Polarizable dielectric model of solvation with inclusion of charge penetration effects. J. Chem.Phys. (2001) 114 5691—5701. 

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