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Matière Molle & Verres
(122) Production(s) de l'année 2016
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Dynamics of colloid accumulation under flow over porous obstacles
Auteur(s): Robert De Saint Vincent Matthieu, Abkarian M., Tabuteau Hervé
(Article) Publié:
Soft Matter, vol. 12 p.1041-1050 (2016)
PMID 26573173
DOI: 10.1039/c5sm01952d
WoS: 000369747900007
18 Citations
Résumé: The accumulation of colloidal particles to build dense structures from dilute suspensions may follow distinct routes. The mechanical, structural and geometrical properties of these structures depend on local hydrodynamics and colloidal interactions. Using model suspensions flowing into microfabricated porous obstacles, we investigate this interplay by tuning both the flow pattern and the ionic strength. We observe the formation of a large diversity of shapes, and demonstrate that growing structures in turn influence the local velocity pattern, favouring particle deposition either locally or over a wide front. We also show that these structures are labile, stabilised by the flow pushing on them, in low ionic strength conditions, or cohesive, in a gel-like state, at higher ionic strength. The interplay between aggregate cohesion and erosion thus selects preferential growth modes and therefore dictates the final shape of the structure.[on SciFinder (R)]
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Heterodyne holography with full control of both the signal and reference arms
Auteur(s): Gross M.
(Article) Publié:
Applied Optics, vol. 55 p.A8-A16 (2016)
Texte intégral en Openaccess :
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Measuring enhanced optical correlations induced by transmission open channels in a slab geometry
Auteur(s): Verrier N., Depreater L, Felbacq D., Gross M.
(Article) Publié:
Physical Review B, vol. 93 p.161114 (2016)
Texte intégral en Openaccess :
Ref HAL: hal-01181347_v2
Ref Arxiv: 1507.08399
DOI: 10.1103/PhysRevB.93.161114
WoS: WOS:000374952800001
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
5 Citations
Résumé: Due to the existence of open channels, light could theoretically be transmitted through disorderedmedia with 100% efficiency. However, because of the large number of channels to be controlledor measured, this has been never observed experimentally. To avoid this difficulty we considerobservables easier to handle experimentally. By measuring the correlations of the field transmittedthrough a disordered medium, we were able to count the number of channels involved in transmissionand to compare this number with theory. For a sample of transmission 1=25, we get a number ofmodes about 15 times smaller than for free space propagation. This figure is in good agreementwith theoretical prediction.
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