Determination of an effective pore dimension for microporous media

Johansson, M. V.; Testa, Fabrice; Perrier, Pierre; Vicente, Jérôme; Bonnet, J.P.; Moulin, Philippe; Graur, Irina

doi:10.1016/j.ijheatmasstransfer.2019.07.062

Cited by 11 publications

(10 citation statements)

References 31 publications

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“…The aperture map has been previously used for the 3D morphological evaluation of porous materials in different fields [ 26 , 28 , 29 ] and was applied here for 2D images. This approach, compared to the commonly used mean intercept length technique, provides local information with a subvoxel precision [ 26 , 30 ].…”

Section: Methodsmentioning

confidence: 99%

Assessment of Bone Microarchitecture in Fresh Cadaveric Human Femurs: What Could Be the Clinical Relevance of Ultra-High Field MRI

et al. 2022

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MRI could be applied for bone microarchitecture assessment; however, this technique is still suffering from low resolution compared to the trabecular dimension. A clear comparative analysis between MRI and X-ray microcomputed tomography (μCT) regarding microarchitecture metrics is still lacking. In this study, we performed a comparative analysis between μCT and 7T MRI with the aim of assessing the image resolution effect on the accuracy of microarchitecture metrics. We also addressed the issue of air bubble artifacts in cadaveric bones. Three fresh cadaveric femur heads were scanned using 7T MRI and µCT at high resolution (0.051 mm). Samples were submitted to a vacuum procedure combined with vibration to reduce the volume of air bubbles. Trabecular interconnectivity, a new metric, and conventional histomorphometric parameters were quantified using MR images and compared to those derived from µCT at full resolution and downsized resolutions (0.102 and 0.153 mm). Correlations between bone morphology and mineral density (BMD) were evaluated. Air bubbles were reduced by 99.8% in 30 min, leaving partial volume effects as the only source of bias. Morphological parameters quantified with 7T MRI were not statistically different (p > 0.01) to those computed from μCT images, with error up to 8% for both bone volume fraction and trabecular spacing. No linear correlation was found between BMD and all morphological parameters except trabecular interconnectivity (R2 = 0.69 for 7T MRI-BMD). These results strongly suggest that 7T MRI could be of interest for in vivo bone microarchitecture assessment, providing additional information about bone health and quality.

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Section: Methodsmentioning

confidence: 99%

Assessment of Bone Microarchitecture in Fresh Cadaveric Human Femurs: What Could Be the Clinical Relevance of Ultra-High Field MRI

et al. 2022

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“…The aperture map has been previously used for the 3D morphological evaluation of porous materials in different fields [ 19 , 28 ]. The aperture map approach, compared to the commonly used mean intercept length technique, provides local information with a sub-voxel precision [ 28 , 30 ].…”

Section: Methodsmentioning

confidence: 99%

Validation and Optimization of Proximal Femurs Microstructure Analysis Using High Field and Ultra-High Field MRI

et al. 2021

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Trabecular bone could be assessed non-invasively using MRI. However, MRI does not yet provide resolutions lower than trabecular thickness and a comparative analysis between different MRI sequences at different field strengths and X-ray microtomography (μCT) is still missing. In this study, we compared bone microstructure parameters and bone mineral density (BMD) computed using various MRI approaches, i.e., turbo spin echo (TSE) and gradient recalled echo (GRE) images used at different magnetic fields, i.e., 7T and 3T. The corresponding parameters computed from μCT images and BMD derived from dual-energy X-ray absorptiometry (DXA) were used as the ground truth. The correlation between morphological parameters, BMD and fracture load assessed by mechanical compression tests was evaluated. Histomorphometric parameters showed a good agreement between 7T TSE and μCT, with 8% error for trabecular thickness with no significative statistical difference and a good intraclass correlation coefficient (ICC > 0.5) for all the extrapolated parameters. No correlation was found between DXA-BMD and all morphological parameters, except for trabecular interconnectivity (R2 > 0.69). Good correlation (p-value < 0.05) was found between failure load and trabecular interconnectivity (R2 > 0.79). These results suggest that MRI could be of interest for bone microstructure assessment. Moreover, the combination of morphological parameters and BMD could provide a more comprehensive view of bone quality.

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“…The data on the mass flow rate are not really presented, but these data are used to determine the effective pore size in Section VI B 2 following the methodology developed in Ref. 13.…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Ref. 13, the gas rarefaction in a porous medium can nevertheless be qualified by a single dimension, the characteristic flow dimension, which, furthermore, gives morphological information of the porous structure. FIG.…”

Section: Introductionmentioning

confidence: 99%

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Low-pressure gas flow properties of sintered stainless steel microporous media

et al. 2022

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The gas flows through the low permeable porous media are of great interest, especially in vacuum technology for filtering, separation processes, protection, and flow control. They can combine a high mass flow rate and a high level of rarefaction. The transient experimental technique, developed previously for the mass flow rate measurements through the microchannels [Rojas Cardenas et al., Phys. Fluids 23, 031702 (2011)], is generalized to obtain the permeability and conductance directly from the pressure variation measurements. The present experimental methodology, allowing for step by step data verification, leads to higher accuracy than the similar and commonly used method such as “pulse-decay” techniques [W. F. Brace and R. J. Martin, Int. J. Rock Mech. Min. Sci. 5, 415–426 (1968)]. The measured data are fitted according to the exponential function with the pressure relaxation time as a single fitting parameter. The permeability and conductance of the sintered stainless steel microporous medium are measured for different gases. By using the methodology proposed by Johansson et al. [Int. J. Heat Mass Transfer 142, 118412 (2019)], the characteristic pore size of the sample was determined to be equal to 1.5 micrometers. It was found that free molecular flow constant conductance is achieved at a pressure below 30 mbar for helium. This property makes this kind of porous media particularly suitable as a leak element by taking advantage of the constancy of conductance in the free molecular flow regime, for example, for calibration of ionization gauges or mass spectrometers [Yoshida et al., Measurement 45(10), 2452–2455 (2012)].

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Determination of an effective pore dimension for microporous media

Cited by 11 publications

References 31 publications

Assessment of Bone Microarchitecture in Fresh Cadaveric Human Femurs: What Could Be the Clinical Relevance of Ultra-High Field MRI

Assessment of Bone Microarchitecture in Fresh Cadaveric Human Femurs: What Could Be the Clinical Relevance of Ultra-High Field MRI

Validation and Optimization of Proximal Femurs Microstructure Analysis Using High Field and Ultra-High Field MRI

Low-pressure gas flow properties of sintered stainless steel microporous media

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