Picatinny Arsenal's process for making alumina coated nanoparticles of aluminum involves the conversion of gaseous aluminum, in the presence of helium carrier gas, to solid nanoparticles and their subsequent reaction with oxygen gas to form the oxide coating. Upon cooling, the aluminum precipitates to form solid nanoparticles. This part of the process can be described by the General Dynamic Equation for aerosols, which is the basis for mathematical modeling. The GDE was formulated as a set of numerical equations with particle volume and reactor holding time as the independent variables. The solution technique employs a set of numerical equations, which are solved explicitly. The solution requires that the integrals describing the ongoing coagulation processes be evaluated numerically at each grid point in the solution space. After all of the gaseous aluminum has solidified, a moment equation is employed to calculate the number of particles in each of the size distribution ranges.
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