AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Automated Primary Particle Sizing of Nanoparticle Aggregates by TEM Image Analysis
Ramin Dastanpour, STEVEN ROGAK, University of British Columbia
Abstract Number: 716 Working Group: Combustion
Abstract Nanoparticle aggregates formed in colloidal or aerosol processes have complex morphology that is commonly characterized by Transmission Electron Microscopy (TEM). Soot, for example, is formed as aggregates of primary particles. Soot properties are influenced by the diameter and the arrangement of its constitutive primary particles. TEM is an accurate method commonly used for the characterization of soot morphology, but manual analysis of the micrographs is extremely labour-intensive. Here, a new method is developed for automatic determination of the average primary particles diameter based on the variation of the 2-D pair correlation function at different distances measured from the main skeleton of the aggregates. It is assumed that the value of the pair correlation function at the average radius of the primary particles is nearly constant. The method has been applied to real soot particles collected from several operating conditions of a gasoline direct injection engine and a heavy-duty compression-ignition engine. Using a constant value for the pair correlation function at the radius of the primary particles (determined from the analysis of TEM images) results in primary particle sizing errors (relative to manual sizing) of ~13% for single aggregates. Correlating the value of the pair correlation function at the radius of the primary particles to the particle shape yields ~14% error in the primary particle sizing. The ensemble-mean average primary particle diameter for manual and automatic sizing differed by ~4%.