The effect of high relative humidity on a network of water-sensitive particles (couscous) as revealed by <i>in situ</i> X-ray tomography

Vego, Ilija; Tengattini, Alessandro; Andò, Edward; Lenoir, Nicolas; Viggiani, Gioacchino

doi:10.1039/d2sm00322h

Cited by 7 publications

(1 citation statement)

References 26 publications

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“…These properties have rendered neutron imaging an attractive tool applicable to a wide array of scientific disciplines, spanning from materials science to biology, archaeology, and geology [2,7,8]. Notably, the measurement of hydrogen distribution, particularly water, holds significant interest and is relevant for many domains, ranging from fuel cells [9], electrolyzer [10], food industry [11], concrete and cement science [12,13], wood and plant research [4,14], fabrics [15], as well as studies of multiphase transport in porous media [16,17], to mention only a few.…”

Section: Introductionmentioning

confidence: 99%

Towards in-situ water quantification via neutron imaging: insights from NeXT-Grenoble

Nemati,

Lukić,

Tengattini

et al. 2024

Meas. Sci. Technol.

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Neutron imaging has gained increasing attention in recent years. A notable domain is the \emph{in-situ} study of flow and concentration of hydrogen-rich materials. This demands precise quantification of the evolving concentrations. Several implementations deviate from the ideal conditions that allow the direct applicability of the Beer-Lambert law to assess this concentration. The objective of this work is to address these deviations by applying both calibration and correction procedures to ensure and validate accurate quantitative measurements during 2D and 3D neutron imaging conducted at the cold neutron source at the NeXT instrument of the Institute Laue-Langevin (ILL), Grenoble, France. Linear attenuation coefficients and non-linear correlations have been proposed to measure the water concentration based on the sample-to-detector distance. Furthermore, the effectiveness of the black body (BB) grid correction method, introduced by Boillat et al. [1], is evaluated which accounts for spurious deviations arising from the scattering of neutrons from the sample and the surrounding environment. The applicability of the Beer-Lambert law without any data correction is found to be reasonable within limited equivalent thickness (e.g., below 4 mm of water) beyond which the correction algorithm proves highly effective in eliminating spurious effects. Notably, this correction method maintains its effectiveness even with transmissions below 1%. We examine here the impact of grid location and resolution with respect to sample heterogeneity.

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Section: Introductionmentioning

confidence: 99%

Towards in-situ water quantification via neutron imaging: insights from NeXT-Grenoble

Nemati,

Lukić,

Tengattini

et al. 2024

Meas. Sci. Technol.

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The influence of water sorption on the microstructure of a hydro-sensitive granular material (couscous) deduced from simultaneous neutron and X-ray tomography

et al. 2023

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The effects of water on the behaviour of granular materials can be significant. Besides capillary bridges, several other chemo-hydro-mechanical processes can affect the response of hydro-sensitive granular assemblies, when water sorption critically alters the individual particles properties (i.e., swelling, deterioration of mechanical properties). It is very common to find such materials in food and pharmaceutical industries, where water sorption can often lead to important resources waste while processing or storing the product. It is therefore necessary to understand the phenomena that affect the material’s functionality, often related to particle agglomeration and degradation. However, despite the relevance of the problem, our knowledge about these phenomena is still relatively poor. With this study we aim to explore the link between water content increase and particle, contacts and assembly scale phenomena. Simultaneous neutron and X-ray tomography allows us to investigate respectively the water uptake and microstructure evolution of two couscous assemblies exposed to high relative humidity while subjected to constant stress, a configuration chosen to simulate the conditions in an industrial silo-storage. We acquire a data-set of images, from which we follow and quantify the variations of water content distribution and the resulting volumetric response of thousands of particles through bespoke algorithms. Despite the abundance of water provided, we observe spatial gradients in water content distribution and consequently in particle swelling. We find that the relation between these two variables can be described as (quasi-)linear. The contact area growth also seems to follow a similar trend. Graphic abstract

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A combined SPH-DEM approach for extremely deformed granular packings: validation and compression tests

Castro

Radl

2023

Comp. Part. Mech.

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We present a novel smoothed particle hydrodynamics-discrete element method (SPH-DEM) approach for the simulation of deformable granular media. First, we show how the method converges to the analytical solution in a simple contact mechanics problem, namely the Hertz contact law for elastic spherical grains. Second, we analyze the evolution of a 2D packing of disks under uniaxial compression, displaying the evolution of key metrics of the packing such as the coordination number and the vertical stress. We show that the code produces data in quantitative agreement with what is known from literature. Finally, we demonstrate that our SPH-DEM coupling can be used to study packings of deformable grains from the onset of jamming to extremely compacted states, reaching packing fractions of $$\phi \simeq 0.995$$ ϕ ≃ 0.995 .

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The effect of high relative humidity on a network of water-sensitive particles (couscous) as revealed by in situ X-ray tomography

Abstract: Water significantly influences the mechanical behaviour of all granular materials but none as much as hygroscopic amorphous particles. With sufficiently high water content, particles can swell, agglomerate and their mechanical...

Cited by 7 publications

References 26 publications

Towards in-situ water quantification via neutron imaging: insights from NeXT-Grenoble

Towards in-situ water quantification via neutron imaging: insights from NeXT-Grenoble

The influence of water sorption on the microstructure of a hydro-sensitive granular material (couscous) deduced from simultaneous neutron and X-ray tomography

A combined SPH-DEM approach for extremely deformed granular packings: validation and compression tests

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