Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Coussot, Philippe

doi:10.1007/s00348-020-03037-y

Cited by 24 publications

(14 citation statements)

References 159 publications

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“…By means of Inverse Laplace Transform (ILT) with a procedure of non‐negative least square fit to the data with Tikhonov regularization (similar to the “Contin” method as in (Provencher, 1982; Whittall & MacKay, 1969)), the transverse relaxation time T 2 distribution can be resolved. We refer to (Coussot, 2020; Faure & Rodts, 2008; Valori et al., 2013) for more details on NMR. Note that the 1D profile and CPMG experiments were carried out intermittently in a loop function, leading to an effective time resolution of around 9.9 min.…”

Section: Methodsmentioning

confidence: 99%

Towards the End of Drying of Granular Materials: Enhanced Evaporation and Drying‐Induced Collapse

Wang

Maillet

Pereira

et al. 2021

Water Resources Research

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Drying of porous media is essential in relation with many applications, such as drugs and cosmetics synthesis in the pharmaceutical industry, thermally enhanced oil recovery, and drying of textiles, grains, and food. Particularly, soil drying is of great environmental importance, as it controls the water, energy and solutes transfer between the atmosphere and subsurface. The basic mechanisms of drying of saturated porous media have been identified as two distinguishable stages (

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Section: Methodsmentioning

confidence: 99%

Towards the End of Drying of Granular Materials: Enhanced Evaporation and Drying‐Induced Collapse

Wang

Maillet

Pereira

et al. 2021

Water Resources Research

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“…The nuclear magnetic resonance imaging (MRI), as a non-invasive and non-destructive method, has proven effective in probing the evolution of saturation profile during the evaporation process [8,31,32]. Here, the drying experiments were also conducted to obtain the evolution of 1D saturation profile using MRI (Bruker Minispec mq20 equipped with a field gradient) under similar experimental conditions as a supplement to provide qualitative characterization of the drying process.…”

Section: Mri Profiling Experimentmentioning

confidence: 99%

“…By means of Inverse Laplace Transform (ILT) with a procedure of non-negative least square fit to the data with Tikhonov regularization (similar to the "Contin" method as in [34,35]), the transverse relaxation time T 2 distribution can be resolved. We refer to [32,36,37] for more details on NMR. Note that the 1D profile and CPMG experiments were carried out intermittently in a loop function, leading to an effective time resolution of around 9.9 minutes.…”

Section: Mri Profiling Experimentmentioning

confidence: 99%

Towards the end of drying of granular materials: enhanced evaporation and drying-induced collapse

Wang

Maillet

Pereira

et al. 2021

Preprint

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We experimentally study the drying of loosely packed wet glass beads at low initial water content. The drying rate is found to decrease at the start, corresponding to the decreasing rate period controlled by vapor diffusion, followed by a deviation in drying rate from the diffusion limited evaporation. The propagation of drying front associated with a sharp saturation gradient is identified through both image analysis and magnetic resonance imaging technique. The drying-induced collapse of granular medium is observed and quantified. The concentrated collapse at the end of drying suggests the existence of liquid in the form of liquid bridges in the apparent dry region until the end of drying process. Collapse event is found to be local, i.e., a clear boundary can be identified for each collapse event, below which the loosely packed medium remains intact. This indicates the existence of a saturation gradient in the apparent dry region. The drying dynamics and collapse statistics suggest that the observed transition of drying regimes is due to Kelvin effect. This work demonstrates for the first time the drying enhancement phenomenon due to Kelvin effect even for grains with size of hundreds of micrometers, and provides insights on the drying process of partially saturated granular materials, especially near the final period of evaporation.

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“…The characterization of laminar flow, including average velocity and velocity profile, is of considerable value in chemical and allied processing industries [2][3][4]. Various fluids exhibit different flow behaviours under laminar conditions, dependent on fluid rheological properties [5][6][7][8]. Laminar flow characterization is therefore helpful to characterize the rheological properties.…”

Section: Introductionmentioning

confidence: 99%

Laminar flow characterization using low-field magnetic resonance techniques

et al. 2021

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Laminar flow velocity profiles depend heavily on fluid rheology. Developing methods of laminar flow characterization, based on low-field magnetic resonance (MR), contributes to the widespread industrial application of the MR technique in rheology.In this paper, we designed a low-cost, palm-sized permanent magnet with a 1 H resonance frequency of 20.48 MHz to measure laminar flow. The magnet consists of two disk magnets, which were each tilted at an angle of 1˚ from a starting separation of 1.4 cm to generate a constant gradient, 65 gauss/cm, in the direction of flow.Subsequently, a series of process methods, for MR measurements, were proposed to characterize Newtonian and non-Newtonian fluid flows in a pipe, including phasebased method, magnitude-based method, and velocity spectrum method. The accuracies of the proposed methods were validated by simulations, and experiments of Poiseuille flow and shear-thinning flow on the designed magnet. The new velocity profile methods proposed are advantageous because the MR instrumentation and measurement methods are simple and portable. The sophistication is found in the analysis although the physical principles are straight forward.

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Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Cited by 24 publications

References 159 publications

Towards the End of Drying of Granular Materials: Enhanced Evaporation and Drying‐Induced Collapse

Towards the End of Drying of Granular Materials: Enhanced Evaporation and Drying‐Induced Collapse

Towards the end of drying of granular materials: enhanced evaporation and drying-induced collapse

Laminar flow characterization using low-field magnetic resonance techniques

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