On the thermophoretic sampling and TEM-based characterisation of soot particles in flames
| Autor: | John R. Agudelo, Maria L. Botero, Jethro Akroyd, Dongping Chen, Markus Kraft |
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| Přispěvatelé: | Chen, D [0000-0002-4232-3356], Apollo - University of Cambridge Repository, School of Chemical and Biomedical Engineering |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Microscope HRTEM Image quality 02 engineering and technology Electron 010402 general chemistry 01 natural sciences law.invention Image analysis Optics law Chemical technology [Engineering] Thermophoretic sampling General Materials Science High-resolution transmission electron microscopy business.industry Sampling (statistics) Thermophoretic Sampling General Chemistry 021001 nanoscience & nanotechnology Soot characterisation 0104 chemical sciences TEM Particle Transmission Electron Microscopy 0210 nano-technology Focus (optics) business Beam (structure) |
| DOI: | 10.17863/cam.58012 |
| Popis: | 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 min 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. National Research Foundation (NRF) The authors gratefully acknowledge the financial support provided by the Colombia Scientific Program within the framework of the call Ecosistema Cientifico (Contract No. FP44842-218-2018), and the National Research Foundation (NRF), Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme. Dr Botero thank COLCIENCIAS for the post-doctorate grant 784. |
| Databáze: | OpenAIRE |
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