Biomedical subjects

F Gruy

Publications and source records attributed to F Gruy.

3 recordsLinked to original sources

PubMed2004

Experimental study of small aggregate settling.

The drag coefficient and hydrodynamic radius of particles are important parameters needed in crystallization science. Small aggregates of micrometric primary particles are mainly produced in stirred crystallizers. We present experimental results on the drag coefficient of macroscopic aggregates consisting of glass beads in the number range [2,100]. The drag coefficient is calculated from settling measurements in glycerol in order to preserve the Stokesian nature of typical flow around particles in a crystallizer. We show that the hydrodynamic radius of these aggregates is almost the radius based on the average projected area over all orientations. This result is extended to larger and more porous aggregates.

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PubMed2000

Turbulent Aggregation of Titania in Water.

This paper deals with the application of two in situ particle sizing methods to the study of aggregation of titanium dioxide in turbulent aqueous solutions. Turbidity measurements are used to characterize aggregation of diluted suspensions (solid volume fraction less than 10(-4)). Analysis of backscattered light can be applied to highly concentrated suspensions. Because in situ measurements are possible, the aggregation process can be followed from its beginning to the final steady state which is always observed. The influences of stirring rate and solid volume fraction on the aggregation dynamics are presented. They are interpreted in the framework of a model of aggregation which takes into account the morphology and the related optical properties of the aggregates and the physical and hydrodynamic interactions between aggregates. The complex relationship between aggregate restructuring and aggregation on one hand, and fragmentation on the other hand, is considered. Copyright 2000 Academic Press.

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PubMed1997

Turbulent Coagulation Efficiency

The coagulation of small particles in a turbulent flow is considered. A kinetic equation based on Levich's theory is proposed. It takes into account the physicochemical and hydrodynamic interactions. The predicted coagulation efficiency is compared to experimental and other theoretical works. Thanks to its compact expression, the coagulation efficiency is much easier to calculate and to manipulate than the relationships derived from other models.

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