Clouds susceptibility

Platnick and Twomey (1994) have applied Eq. (KK) to marine clouds off the coast of California and southern Africa, to fogs in central California, and to ship tracks. Figure 14.42 shows a typical range of susceptibilities as a function of cloud droplet size. The measured susceptibilities in these studies covered three orders of magnitude, from 5 X 10-5 cm3 for fogs to 0.8 X 10-3 cm3 for marine clouds off south Africa and 2 X 10 2 cm3 for thin stratus clouds off the California coast. Similarly, Taylor and McHaffie (1994) report cloud susceptibilities in the range from 10-4 to >8 X 10-3 at various locations around the world. The highest susceptibilities were those with the smallest aerosol particle concentrations below the cloud base. As the particle concentration increased beyond 500 cm3, the susceptibility was relatively constant at 5 X 10"4 cm3. This means that the addition of new particles to a relatively clean air mass is far more effective than for a polluted one in terms of the effect on clouds. In short,... 

FIGURE 14-42 Cloud susceptibilities (logarithmic scale) and cloud droplet radii for stratus clouds off Africa and California and from fogs in California (adapted from Platnick and Twomey, 1994). 

One of the results of this variety in hydrogen-defect reaction pathways is that it largely clouds one of the hopes of the hydrogenation experiments, namely that the susceptibility of deactivation could provide information on the defect microstructure and the nature of the bonding with hydrogen. 

Additional evidence on electron-cloud radii is given by diamagnetic susceptibility and by refractive index. For the well-known Larmor-Langevin theory of diamagnetism (11—13) gives for the molecular diamagnetic susceptibility —Xm the formula... 

The molecular susceptibility Xm gives therefore directly the root-mean-square radiusyrms of the electron-cloud in 1918 and earlier years this formula provided one of the best ways of estimating atomic radii" (14) which are obviously electron-cloud radii y and not structural radii r. 

The next Table investigates these questions more fully. The second column shows the diamagnetic susceptibility, and the third the inner-electron effect calculated as before (75). Subtracting this effect, the ms electron-cloud radii follow immediately from Eq. (1). 

If the electron-cloud radius yrms were exactly equal to the structural radius r, Wasastjerna s criterion would be obviously true. But in fact, for ions r ce. 2 yrms (Table 3). Hence the criterion needs justification. It is obviously most probable for isoelectronic ions (cp. Eauling (/)), but the electron-cloud radii should refer to the ions in the crystals, not to the free ions. For, with a gross difference between crystal and free-ion electron-cloud radii for the hydride ion, there may be significant differences for others 40). For the crystals the electron-cloud radii could be obtained either from polarizeability or from magnetic susceptibility. The theory of polarizeability is less certain and there is a considerable correction to infinite wavelength. We therefore adopt the magnetic evidence. But this must be corrected for the inner shell contribution (Table 3). 

The focal helds set up a polarization in the material. In the case of CARS, we are interested in the polarization resulting from the combined action of the pump (of frequency co ) and Stokes (of frequency coj beams, which induce motions in the electron clouds that oscillate at frequency 2co - co, the anti-Stokes frequency. The ability of the material to oscillate at the anti-Stokes frequency when the pump and Stokes helds are present is given by the third-order nonlinear susceptibility The strength of the polarization is furthermore determined by the amplitude of the pump (E ) and Stokes (E ) driving helds. In the tensorial notation, where and I denote the polarization components of the nonlinear susceptibility, the third-order polarization in the polarization direction i is given as... 

The nonresonant contributions pertain to electron cloud oscillations that oscillate at the anti-Stokes frequency but do not couple to the nuclear eigenfrequencies. These oscillatory motions follow the driving fields without retardation at all frequencies. The material response can, therefore, be described by a susceptibility that is purely real and does not depend on the frequencies of the driving fields. The resonant contributions, on the other hand, are induced by electron cloud oscillations that are enhanced by the presence of Raman active nuclear modes. The presence of nuclear oscillatory motion introduces retardation effects relative to the driving fields i.e., there is phase shift between the driving fields and the material oscillatory response. 

An unprotected person exposed to H vapor will suffer simultaneously from skin burns, eye injury, and irritation of the respiratory tract.20 The acute effects of H depend on the concentration of the gas, the duration of exposure, the ambient temperature, the extent of protection, and the susceptibility of the person.23 Clothing will be contaminated and become a secondary source of poisoning even after a gas cloud has blown away. 

Pincus, R., and M. B. Baker, Effect of Precipitation on the Albedo Susceptibility of Clouds in the Marine Boundary Layer, Nature, 372, 250-252 (1994). 

Platnick, S., and S. Twomey, Determining the Susceptibility of Cloud Albedo to Changes in Droplet Concentration with the Advanced Very High Resolution Radiometer, J. Appl. Meteorol., 33, 334-347 (1994). 

The production of sweet table wines at home presents many more problems than does the production of dry wines. Low alcohol (10-13 vol % ) sweet wines are susceptible to further fermentation, and the sugar is also capable of supporting the growth of several undesirable types of bacteria. When these further transformations occur after the wine has been put into bottles, the result is the production of unsightly clouds, the trapping of the generated C02, and the production of unpleasant flavors. 

If steps are not taken to stabilize cloud, most citrus juices will clarify when allowed to stand. Clarification occurs when native PE lowers the ester content of juice soluble pectin until it becomes susceptible to precipitation as insoluble pectates (23). If pectin levels are high enough, as in concentrates, these pectates may form a gel. 

Aromatic Hydrocarbons. The rr-election cloud of the aromatic ring is much more susceptible to electron removal than a saturated hydrocarbon. Thus, benzene is oxidized at +2.45 V versus SCE electron-donating substituents reduce... 

Let us look at the benzene-cyclohexane separation more closely as we summarize how GC works. The boiling points of benzene and cyclohexane are nearly the same, 80.1 and 81.4°C respectively. Any GC separation will have to depend on differences in the intermolecular interactions between the stationary phase and these two analytes, both of which are nonpolar hydrocarbons. What differences could be exploited with GC Benzene has a -n-electron cloud, which should make it more susceptible to induction effects and perhaps dispersion attractions (Chapter 3). Therefore we should choose a stationary liquid phase that would accentuate this difference—a polar one also, using the like-dissolves-like rule we might choose an aromatic compound that would interact more with benzene than with cyclohexane. One possible liquid phase that meets these criteria is dinonylphthalate, and it has been used to separate benzene and cyclohexane. The relative retention has been found to be 1.6, which represents a very good separation.1... 

If KSt values are not known, sometimes the potential explosibility of a dust cloud can still be estimated. Chemical groups such as organic peroxides and some nitro compounds are especially susceptible, as are materials containing significant quantities of oxygen readily available for combustion. With the following basic reaction... 

Complexation has a marked effect on reactivity because it removes electron density from the 7i-cloud. This makes both the ring and the side chain of the arene acidic and therefore susceptible to nucleophilic attack. The electron-withdrawing effect of the chromium is comparable to that of a nitro group (see Chapter 7). 

Caldeira K., and Kasting J. F. (1992) Susceptibility of the early Earth to irreversible glaciation caused by carbon dioxide clouds. Nature 359, 226—228. 

A comprehensive theory of electric polarizabilities and magnetic susceptibilities has been developed [4-6], which accounts for the electromagnetic moments induced in the electron cloud by the switching on of an external time-dependent perturbation. 

The minimum ignition energy (MIE) test determines the lowest electrostatic spark energy that is capable of igniting a dust cloud at its optimum concentration for ignition. The test is used primarily to assess the potential susceptibility of dust clouds to ignition by electrostatic discharges. 

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