Giant particles

Integral equations have been developed for inhomogeneous fluids. One such integral equation is that of Henderson, Abraham and Barker (HAB) [88] who assumed the OZ equation for a mixture and regarded the surface as a giant particle. For planar geometry they obtained... 

Eq. (101) is the multidensity Ornstein-Zernike equation for the bulk, one-component dimerizing fluid. Eqs. (102) and (103) are the associative analog of the singlet equation (31). The last equation of the set, Eq. (104), describes the correlations between two giant particles and may be important for theories of colloid dispersions. The partial correlation functions yield three... 

Meszaros A., Vertical profile of large and giant particles in the lower troposphere. In Proc. Int. Conf. on Condensation and Ice Nuclei, September 18-24, 1969. Prague, Vienna, 1979, pp. 86-90. 

This division is very convenient from the point of view of particle characterization and measurement. Thus, in the range of Aitken particles diffusion effects are significant and particle coagulation is rapid. However, in case of giant particles these phenomena can be neglected and the behaviour of aerosol particles is mostly determined by their sedimentation due to gravitation. The large particles constitute... 

Nomenclature / Aitken Large particles jarticles Giant particles / ... 

Finally, many viruses, bacteria, pollens and spores can be found in the lower atmosphere. The size of viruses and bacteria is small, while the pollens and spores are in the giant size range. According to A. Meszaros (1977), on an average 20 of the giant particles in clean continental air are composed of pollen and spores during the appropriate seasons. The biological importance of these airborne materials is obvious. 

On the basis of his atmospheric impactor measurements Junge (1963) proposed a power law to describe the size distribution of large and giant particles ... 

Size distribution of large and giant particles at various altitudes (BlifTord, 1970). (By courtesy of the... 

In the upper troposphere the size distribution of large and giant particles was investigated by Soviet (Kondratyev et al.. 1969) and American (Blifford. 1970) research workers. Particles were collected by impactors in both cases. Figure 29 shows Blifford s size distributions for different altitudes, obtained over Nebraska, U.S.A. An interesting feature emerging from the distributions presented is the decrease in the steepness of the slope in the distributions (that is the value of fi in equation [4.12] decreases). It is very difficult to explain this peculiarity of aerosol behaviour. However, it is believed that the removal of aerosol particles by cloud elements (Chapter 5) plays an important role in control of the size distribution of aerosol particles in the troposphere. 

Concentration aid vertical profile of large aad giant particles... 

Mass concentration (M) of various soluble components in the giant particle size range under different geographical conditions (Junge, 1963). Curve (h) gives sulfate concentrations calculated from ammonium concentrations and the stoichiometric ratio of SO4 to NH4 in ammonium sulfate. (By courtesy of... 

The raindrop will wash out a fraction eMt of this mass, where e is the impaction efficiency as defined in Subsection 4.1.2 (for its numerical value see Mason, 1957). If the drop radius lies between 50-2000 pm the impaction efficiency is 1 for 10 pm g r < R and decreases with decreasing particle size. It ranges from 0.5 to 0.1 if the particle radius varies between 5 pm and 2 pm. This indicates that only giant particles in the coarse mode (Subsection 4.3.2) are significantly washed out below the clouds. Let us multiply the right-hand side of equation [5.16] by e and divide the result by the volume of the raindrop. This yields the trace concentration in the drop (C2a) due to the capture of aerosol particles ... 

Figure 7-7 shows further that the marine aerosol features a more pronounced growth with relative humidity than continental aerosols. The reason is the greater content of water-soluble material. For giant particles, the growth... 

Fig. 8-7. Washout coefficients according to Slinn and Hales (1971) are shown in curves A and B (left-hand scale). They are based on rain drop size spectra of Zimin (1964) with r,max = 0.2 and 1 mm, respectively, and a precipitation rate of 10 mm/h (10 kg/m2 h). Curve C represents the first term and curves D and E the second term in the bracket of Eq. (8-6) in nonintegrated form (right-hand scale applies). These latter three curves are based on the mass-size distribution for the rural continental aerosol in Fig. 7-3. Curve C was calculated with eA(r2)=l for r2>0.5 ra and eA < I for r2<0.5(im, decreasing linearly toward zero at r2 = 0.06 p.m. This leads to eA = 0.8. Curves D and E were obtained by using the washout coefficients of curves A and B, respectively. Note that below-cloud scavenging (curves D and E) affect only giant particles, whereas nucleation scavenging (curve C) incorporates also submicrometer particles.

The Stanford Linear Accelerator Center has three giant particle spectrometers, which are used to detect subatomic particles of different energies. This is the largest linear accelerator in the world. 

De Leeuw, G. (1986) Vertical profiles of giant particles close above the sea surface, Tellus 38B, 51-61. 

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