The analysis of time variation of size distribution of large particles observed on Minami-torishima Is. (24 ° 18' N, 152 ° 58' E) is shown. In the observation, an optical particle counter is used which is similar to the Royco counter in principle. The counter gives the size distribution of particles with a diameter of 0.5 to 10 μm (in the ambient humidity) in 15 size intervals, assuming spherical particles with an optical refractive index of 1.4. In the analysis, emphasis was laid on estimating the deposition velocity and production rate of sea-salt particles from the foam belt encircling the Island, as a function of particle size. The inferred production rate of seawater droplets of diameter intervals of 0.9 ∼ 1.8, 1.8 ∼ 3.5, 3.5 ∼ 7.6 and 7.6 μm is 1.2, 0.7, 0.5 and 0.07 × 103 droplets s-1 per 1 cm2 of the foamy area, respectively.
The three theoretical flow models, simple source flow model, impaction flow model and efflux flow model, were developed to predict the inertial capture of aerosol particles during bubble formation. The collection efficiencies of the bubble columns with perforated plate of 0.3 mm and 0.5 mm in diameter were measured under various conditions of aerosol flow rate and submergence, using the monodisperse latex aerosols. The collection efficiency corresponding to zero submergence was assumed to be the collection efficiency during bubble formation. The obtained collection efficiencies were compared with theoretical model predictions. The efflux flow model was found to give the better agreement with experiments than other models.
A series of experiments was carried out to prepare the ultrafine particle of stannic oxide via gas phase chemical reaction. The effect of reaction conditions, such as the partial pressure of SnCl4 vapor and of O2 or H2O, reaction temperature and the residence time, was investigated. The identification, mean size, size distribution and shape of particles were studied by X-ray diffraction, T. E. M. observation and B. E. T. specific surface area measurement. The products were identified as stannic oxide, white in color, several tens of nm in size, platelike in shape. The average size of oxide particles become smaller with lower PSnCl4 and higher PH2O and higher temperature. The residence time had materially no effect.