Fractal Dimension Analysis of Single, In-Situ, Restructured Carbonaceous Aggregates

The fractal dimension (DJ 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 (dAE ), hence allowing the number of primary spherules in the aggregate, the dynamic shape factor X 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.