PARTICLE SIZE MEASUREMENT BY ELECTRIC BIREFRINGENCE TECHNIQUE AND THEIR COMPARISONS WITH DYNAMIC LIGHT SCATTERING AND CENTRIFUGE DATA.

The pulse electric field birefringences measurements have been carried out for iron oxide particles for the determination of the aspect ratio and rotational diffusion coefficient. Data obtained with this technique are compared with those determined by dynamic light scattering, cylindrical aerosol centrifuge and cascade impactors. The significant agreement between these different sizing methods shows the reliability of this pulse electric light scattering method. Although the orientation mechanism needs further investigations, the general results show that this electro-optical setup can be used as a real time instrument to measure the size of anisometric particles. The translational and rotational diffusion coefficients of fibrous aerosols of average length ratios of 40 to 50 with different thicknesses have been investigated. It can generally be concluded that pulse electric light scattering can be applied to aerosols as a very straight forward method to measure the size distribution of irregularly shaped particles.