USING FRACTAL SCALING AND 2-DIMENSIONAL PARTICLE-SIZE SPECTRA TO CALCULATE COAGULATION RATES FOR HETEROGENEOUS SYSTEMS

Fractal scaling is usually presented as a relationship between aggrega te mass and length. Such scaling can also be expressed as a relationsh ip between the lengths of two particles that collide and the length of the resulting aggregate. Emphasizing fractal scaling as a geometric p roperty allows the extension of fractal description to aggregates comp osed of more than one type of source particle. In particular, it allow s the development of more complete models of the role of coagulation i n marine ecosystems. The classical aggregation equations can be modifi ed to accommodate a two-dimensional particle size spectrum. This two-d imensional set of equations can be solved using a modification of the sectional approach. Because moving to two-dimensions vastly increases the number of possible interactions and makes solution more computatio nally costly, simplifications that decrease the allowable interactions considerably speed up the calculations for relatively little loss of accuracy. (C) 1998 Academic Press.