Characterisation of flame-generated soot and soot-in-oil using electron tomography volume reconstructions and comparison with traditional 2D-TEM measurements

Orhan, Osman; Haffner-Staton, Ephraim; Rocca, A. La; Fay, Michael W.

doi:10.1016/j.triboint.2016.09.015

Cited by 30 publications

(27 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additionally, previous works (including that of the authors) have considered the discrepancy between 2D‐ and 3D‐derived morphological parameters via 3D models of simulated (Rogak & Flagan, ; Martos et al ., ) and real soot agglomerates (van Poppel et al ., ; Orhan et al ., ). Van Poppel observed that values of surface area and volume from 2D methods were up to 16 and 125 times larger (respectively) than the real 3D‐derived values (van Poppel et al ., ).…”

Section: Emphasis For 3d Characterizationmentioning

confidence: 97%

“…Rogak's study of simulated agglomerates observed that fractal dimension was generally underestimated by 10–20% when using 2D methods (Rogak & Flagan, ). Our own study found agreement with Rogak's work and additionally that volume could be underestimated by up 40% via 2D methods (Orhan et al ., ). Recently, Martos’ study of a large number of simulated agglomerates found that 2D‐derived radius of gyration underestimated the true values by over 45%, leading to a corresponding overestimation of fractal dimension (Martos et al ., ).…”

Section: Emphasis For 3d Characterizationmentioning

confidence: 97%

“…The algorithms range from computationally cheap and, in theory, less accurate, to more sophisticated and time consuming iterative methods. Weighted back‐projection (WBP) is one of the simplest and most widely used algorithms, and depending on the software, hardware and number of pixels in the tilt series images, can complete in under a minute (Orhan et al ., ). The simultaneous iterative reconstruction technique (SIRT) is another widely used method that involves some degree of back‐projection, and depending on the number of iterations can take several hours to complete (Fernandez, ).…”

Section: Emphasis For 3d Characterizationmentioning

confidence: 97%

“…Oil samples were diluted in heptane at a ratio of 1:60, then deposited onto the grid before further washing with diethyl ether. Further details of this procedure can be found in previous publications (La Rocca et al ., ; Orhan et al ., ). Colloidal gold nanoparticles in aqueous suspension were deposited onto the grid to aid alignment of images.…”

Section: Experimental Setup and Sample Preparationmentioning

confidence: 97%

See 3 more Smart Citations

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Haffner-Staton

Rocca

Fay

2018

Journal of Microscopy

Self Cite

View full text Add to dashboard Cite

The aim of this work is to make progress towards the development of 3D reconstruction as a legitimate alternative to traditional 2D characterization of soot. Time constraints are the greatest opposition to its implementation, as currently reconstruction of a single soot particle takes around 5-6 h to complete. As such, the accuracy and detail gains are currently insufficient to challenge 2D characterization of a representative sample (e.g. 200 particles). This work is a consideration of the optimization of the steps included within the computational reconstruction and manual segmentation of soot particles. Our optimal process reduced the time required by over 70% in comparison to a typical procedure, whilst producing models with no appreciable decrease in quality.

show abstract

Section: Emphasis For 3d Characterizationmentioning

confidence: 97%

Section: Emphasis For 3d Characterizationmentioning

confidence: 97%

Section: Emphasis For 3d Characterizationmentioning

confidence: 97%

Section: Experimental Setup and Sample Preparationmentioning

confidence: 97%

See 2 more Smart Citations

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Haffner-Staton

Rocca

Fay

2018

Journal of Microscopy

Self Cite

View full text Add to dashboard Cite

show abstract

“…Issues of lengthy sample preparation and extensive data analysis, often taking several days per sample measured, make TEM analysis of soot a time consuming and expensive technique. Furthermore, large uncertainties have been recently reported in 2D-measured morphological parameters, such as the radius of gyration and the fractal dimension of soot agglomerates [18], related to the 01/01/2018 approximation and correction factors intrinsically embedded in the calculation of such parameters, as well as the imaging of two dimensional projections of three-dimensional structures. Circularity, defined as a function of area and perimeter, does not require use of correction factors [19] and will be used in this study to characterise the geometrical features of soot agglomerates.…”

Section: Introductionmentioning

confidence: 99%

Morphological Characterisation of Diesel Soot in Oil and the Associated Extraction Dependence

Key¹,

Rocca²,

Fay³

et al. 2018

SAE Technical Paper Series

View full text Add to dashboard Cite

The size and morphology of soot particles and agglomerates extracted from lubricating oil drawn from the sump of a diesel engine have been investigated and compared using Transmission Electron Microscopy (TEM) and Nanoparticle Tracking Analysis (NTA). Samples were prepared for electron microscopy imaging by both centrifugation and solvent extraction to investigate the impact of these procedures on the morphological characteristics, such as skeleton length and width and circularity, of the obtained soot. It was shown that centrifugation increases the extent of agglomeration within the sample, with 15% of the agglomerates above 200 nm compared to only 11% in the solvent extracted soot. It was also observed that the width of centrifugation extracted soot was typically 10 nm to 20 nm larger than that of solvent extracted soot, suggesting that centrifugation forces the individual agglomerate chains together. Moreover, centrifugation fails to extract a large percentage of particles below 50 nm, with only 4% of the agglomerates smaller than 50 nm in the centrifugation extracted soot, whereas agglomerates in this size range accounted for 19 % using solvent extraction. As TEM represents a comparatively time and cost expensive characterisation tool, unsuitable for high throughput testing required by industry, NTA was explored as a low cost, rapid alternative method for measuring particle size. It was found that results generated by NTA, within the limits of detection, correlated well with those obtained using TEM. This correlative electron microscopy and light scattering approach was further used to appraise the morphological characteristics of two commercial sources of carbon black (CB), enabling the selection of the most suitable soot surrogate, essential for the further development of oils with optimised functional properties.

show abstract

3‐D X‐ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

et al. 2021

View full text Add to dashboard Cite

Catalyst deactivation involves a complex interplay of processes taking place at different length and time scales. Understanding this phenomenon is one of the grand challenges in solid catalyst characterization. A process contributing to deactivation is carbon deposition (i. e., coking), which reduces catalyst activity by limiting diffusion and blocking active sites. However, characterizing coke formation and its effects remains challenging as it involves both the organic and inorganic phase of the catalytic process and length scales from the atomic scale to the scale of the catalyst body. Here we present a combination of hard X-ray imaging techniques able to visualize in 3-D the distribution, effect and nature of carbon deposits in the macropore space of an entire industrially used catalyst particle. Our findings provide direct evidence for coke promoting effects of metal poisons, pore clogging by coke, and a correlation between carbon nature and its location. These results provide a better understanding of the coking process, its relation to catalyst deactivation and new insights into the efficiency of the industrial scale process of fluid catalytic cracking.

show abstract

Characterisation of flame-generated soot and soot-in-oil using electron tomography volume reconstructions and comparison with traditional 2D-TEM measurements

Cited by 30 publications

References 58 publications

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

Morphological Characterisation of Diesel Soot in Oil and the Associated Extraction Dependence

3‐D X‐ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Contact Info

Product

Resources

About