排序方式: 共有32条查询结果,搜索用时 187 毫秒
1.
Ben Abdelouahab N. Gossard A. Ma X. Dialla H. Maillet B. Rodts S. Coussot P. 《Cellulose (London, England)》2021,28(9):5321-5334
Cellulose - This study concerns the spatial evolution of the internal components of a macroscopic sample of cellulose slurry during its convective drying. In a first stage, some water is extracted... 相似文献
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Alexandre Ragouilliaux Benjamin Herzhaft François Bertrand Philippe Coussot 《Rheologica Acta》2006,46(2):261-271
To have a better knowledge of problems occurring with drilling fluids in complex wells, we carried out a detailed rheological analysis of a typical drilling mud at low shear rates using both conventional rheometry and MRI velocimetry. We show the existence of a viscosity bifurcation effect: Below a critical stress value, the mud tends to completely stop flowing, whereas beyond this critical stress, it reaches an apparent shear rate larger than a finite (critical) value, and no stable flows can be obtained between this critical shear rate value and zero. These results are confirmed by MRI velocity profiles, which exhibit a slope break at the interface between the solid and the liquid phases inside the Couette geometry. Moreover, this viscosity bifurcation is a transient phenomenon, the progressive development of which can be observed by MRI. A further examination of MRI data shows that, in the transient regime, the shear rate does not vary monotonously in the rheometer gap and is particularly large along the outer (rough) cylinder, which might be at the origin of the development of a region of constant shear rate in the apparent flow curve. 相似文献
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Coussot G Perrin C Moreau T Dobrijevic M Le Postollec A Vandenabeele-Trambouze O 《Analytical and bioanalytical chemistry》2011,399(3):1061-1069
The covalent immobilization of synthetic or natural macromolecular compounds containing amino groups onto polystyrene (PS)
solid surfaces is of great interest in diagnostic applications. A sensitive assay allowing the determination of reactive end
groups is therefore a powerful tool for predicting the performance of the active surface. Recently, we reported the use of
the Coomassie brilliant blue (CBB) colorimetric reagent to quantify protonated groups (N+) in linear and dendritic structures in solution (Coussot et al., Polym Int 58(5):511–518, 2009). In this work, a simple method using CBB dye for the characterization of PS aminated solid surfaces is developed. The proposed
amino density estimation by colorimetric assay (ADECA) method is based on the reversible complexation of the dye with the
N+ groups on solid surfaces. The assay measures the released dye thanks to the use of a unique sodium carbonate–methanol buffer.
Thereby, for the first time, the same surface can be used for characterization and for further coupling applications. A surface
density of four N+ groups per square nanometer can be measured in PS microwell format, the whole characterization being done within 30 min.
Performances of this new colorimetric-based method are detailed. The ADECA method is further demonstrated to be useful for
the characterization of aminated polypropylene and glass materials with various sizes and shapes. 相似文献
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Jammed systems all have a yield stress. Among these materials some have been shown to shear-band but it is as yet unclear
why some materials develop shear-band and some others do not. In order to rationalize existing data concerning the flow characteristics
of jammed systems and in particular understand the physical origin of such a difference, we propose a simple approach for
describing the steady flow behaviour of yield stress fluids, which retains only basic physical ingredients. Within this framework
we show that in the liquid regime the behaviour of jammed systems turns from that of a simple yield stress fluid (exhibiting
homogeneous flows) to a shear-banding material when the ratio of a characteristic relaxation time of the system to a restructuring
time becomes smaller than 1, thus suggesting a possible physical origin of these trends. 相似文献
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Transport in Porous Media - We study the impact, on the drying rate, of the presence of suspended elements, such as calcium sulfate ions, in the interstitial fluid of a porous medium. In order to... 相似文献
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Coussot P 《Physical review letters》2005,95(7):078303
Brownian motion in soft-jammed systems (pastes) is directly described by taking into account the specific mechanical characteristics of the material surrounding the moving object. In particular we obtain explicit forms for the fluctuation-dissipation equation and the specific characteristics of diffusion through a soft-jammed system. 相似文献
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General probabilistic approach to the filtration process 总被引:1,自引:0,他引:1
We show experimentally that clogging is basically a matter of the probability of the presence of particles. We describe this process as a function of the main variables of the process, namely, the ratio of particle to mesh hole size, the solid fraction, and the number of grains arriving at each mesh hole during one test, with the help of a simple model, the predictions of which are in very good agreement with our experimental data. 相似文献
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Coussot G Faye C Ibrahim A Ramonda M Dobrijevic M Le Postollec A Granier F Vandenabeele-Trambouze O 《Analytical and bioanalytical chemistry》2011,399(6):2295-2302
The functionalization of surfaces with amino groups is used in many application areas such as in industrial biocatalytic processes
for the development of medical biomaterials and in the environment for removing pollutants from water. Amino group density
and grafting stability are often related to functionalized material performances; thus, their characterizations are of prime
importance. The determination of amino density and grafting stability on polymeric material (e.g. polypropylene, polystyrene
and cylco olefin copolymer) is often time consuming and sometimes presents technical constraints, more particularly with non-flat
materials. In this paper, we report a novel colorimetric assay using the Coomassie Brilliant Blue dye for both amino density
determination and grafting stability measurement. The assay named ADECA for “Amino Density Estimation by Colorimetric Assay”
is sensitive, rapid, robust and versatile. We demonstrate that ADECA makes the evaluation of aminated materials performances
possible for numerous material compositions, formats and chemistries used for grafting. Our study focuses on dendrigraft of
poly-l-lysine and poly(amidoamine) dendrimers dendritic materials. 相似文献
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