Particle size spectrum

The present study begins with Zhdanov s results and describes the influences of the alkali, Si02 source, K ions and temperature on the progress of the reaction and particle size spectrum of zeolite A. Comprehensive evaluation of these kinetic investigations permits predictions about nu-cleation and crystal growth which are not restricted to the formation of zeolite A, which had been chosen as a model reaction in the present case. 

Figure 4.6. Spray nozzle and atmospheric particle size spectrum. (BETE Fog Nozzle, Inc., 1994).

As described above, wet and dry particle-bound deposition are likely important for the accumulation of the higher chlorinated PCDD/Fs in aerial vegetation. The accumulation of particle-bound PCDD/Fs in plants is a function of a myriad of factors. The deposition rate itself is influenced by the particle size spectrum in the atmosphere and the distribution of the PCDD/Fs on the different particle size fractions, and further by the atmospheric turbulence, the canopy and plant properties, and the frequency and intensity of precipitation. The retention of the contaminants on the plant surface depends on the degree to which the particles are permanently retained on the plant and, for those particles which are not retained, the degree of transfer of PCDD/Fs from the particles to the plant cuticle. This is a very complex system that is not yet well understood. One approach that... 

Important issue for urban dispersion modelling is the characteristics of the release, e.g., radiochemical composition, density for gases, size distribution for aerosols, etc. For radioactive aerosols the particle size distribution (e.g., number of modes, distribution type, average diameter and standard deviation for each mode, density, and nuclides) varies significantly for different release types and from one nuclide to another. The particle size spectrum could be very broad, e.g. 0.001-200 fim. 

Walter (1973) has studied the evolution of the particle size spectrum by coagulation for the case where new particles with a radius of 1.2 x 10-3 j.m are continuously generated by nucleation processes. Some of his results are shown in Fig. 7-5. The left-hand side shows the evolution of the size spectrum when other particles are initially absent. A secondary maximum develops... 

Friedlander, S. K. On the Particle-Size Spectrum of Atmospheric Aero-... 

Particle size and size distribution are important factors in determining the usability of the extender. The particle size spectrum produced by micronization corresponds to a Gaussian distribution. The size spectrum is numerically characterized by the mean particle size the fines, an upper limit, and by the screen oversize. 

The FIDs rely only on the amount of combustible material present, rather than light absorption or refraction characteristics of the solvent. This should make Aem respond more uniformly to mass over the particle size spectrum than RI or UV detectors. However, the literature indicates that nonuniformities are still a problem. Saturates and aromatics gave different response factors, possibly as a result of different carbon-hydrogen ratios in the materials. The differences in response were comparable to those in RI or UV detectors. These detectors are generally more expensive and more difficult to operate than RI or UV detectors, however. 

Friedlander, S. K., Similarity Considerations for the Particle Size Spectrum of Coagulating, Sedimenting Aerosol, J. Meteor., 17, 479-483, (1960). 

Friedlander, S.K. (1961). Theoretical considerations for the particle size spectrum of the stratospheric aerosol. Am. Meteor. Soc. J. Meteor. 18, 753-759. 

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