Repository logo
 

On the thermophoretic sampling and TEM-based characterisation of soot particles in flames

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Botero, ML 
Akroyd, J 
Kraft, M 
Agudelo, JR 

Abstract

Thermophoretic sampling and TEM imaging are common techniques used to characterise soot particles in flames. In this paper, we present a multi-scale evaluation of operating conditions and methodological aspects of these techniques, and based on our own experimental observations, show how these can influence the characterisation of the particles. Regarding the thermophoretic sampling of soot particles in flames, we evaluated the influence of exposure time, transit times, multiple-insertions, probe design and vibrations in the capture of representative samples, and present a series of recommendations. For the nano-structural characterisation of soot particles using HRTEM combined with fringe analysis we evaluated the influence of microscope alignment and image quality in the mapping of fringes and the calculation of metrics, concluding that the fringe lengths and inter-fringe spacing are very sensitive to particle focus. Also, the parameters used in the image transformation process are critical and require optimisation for different magnifications and microscopes. Finally, the effect of beam damage was studied, confirming a time of approximately 6 minutes during which both nascent and mature particles can be imaged without noticeable nano-structural damage. The use of lower microscope electron voltage can further minimise the impact of beam damage.

Description

Keywords

Thermophoretic sampling, TEM, Image analysis, Soot characterisation, HRTEM

Journal Title

Carbon

Conference Name

Journal ISSN

0008-6223
1873-3891

Volume Title

171

Publisher

Elsevier BV