Fractal dimension analysis of single, in-situ, restructured carbonaceous aggregates

Abstract

The fractal dimensiona (D) of progressively restructured carbonaceous aggregates was investigated, whereby a modified Millikan cell allowed the measurement of D for a single, in situ aggregate in three-dimensional space. The technique relies on simultaneous measurement of the volume equivalent diameter (d VE) and the aerodynamic diameter (d AE), hence allowing the number of primary spherules in the aggregate, the dynamic shape factor χ and D to be determined. Several stages of aggregate restructuring to a more spherical morphology, induced by reversal of the DC electric field, were observed and at each stage D was measured. Such electrostatic restructuring resulted in D exhibiting a limiting value, as high as 2.2 in some cases, beyond which additional increase by this method was not possible. © 1995 American Association for Aerosol Research Published by Elsevier Science Inc.