Moruzzi, RB;
de Oliveira, AL;
da Conceicao, FT;
Gregory, J;
Campos, LC;
(2017)
Fractal dimension of large aggregates under different flocculation conditions.
Science of The Total Environment
, 609
pp. 807-814.
10.1016/j.scitotenv.2017.07.194.
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Abstract
The two-dimensional fractal dimension (Df) of large aggregates of kaolin (> 540 μm) during the shear flocculation process for kaolin solution was investigated using non-intrusive in situ image-based acquisition system. Separate experiments were also carried out for three different sized sub-ranges of large aggregates (0.540–1.125 mm; 1.125–1.750 mm; 1.750–2.375 mm). Digital images were taken at a frequency of 10 Hz for 10 s for each different pairs of gradients of velocity (Gf) of 20 and 60 s− 1 and flocculation times of 2; 3; 4; 5; 10; 20; 30; 60; 120 and 180 min. For the same conditions, particle size distribution (PSD) was also determined. Under the investigated conditions, the lowest Gf produced the greatest Df (1.69) at a flocculation time of 30 min for the whole range of aggregates. Also, the evolution of the longest length of aggregate (l) and Df with time, showed that the dynamic steady-state was reached at different times for each shear rate and l ranges. However, Df varied for each size sub-range (ca. 1.1 to 1.8). Finally, the behavior of the aggregate structure may be understood by the predominance of different aggregation mechanisms such as cluster-cluster for Gf of 60 s− 1 and particle-cluster for Gf of 20 s− 1.
| Type: | Article |
|---|---|
| Title: | Fractal dimension of large aggregates under different flocculation conditions |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.scitotenv.2017.07.194 |
| Publisher version: | http://doi.org/10.1016/j.scitotenv.2017.07.194 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Flocculation,Fractal dimension,Shear rate,Aggregates |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10050637 |
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