Modeling Combined Fabric Evolution in an Anisometric Granular Material Driven by Particle-Scale X-Ray Measurements

2022 ◽  
Vol 148 (1) ◽  
Author(s):  
Rui Wang ◽  
Gustavo Pinzón ◽  
Edward Andò ◽  
Gioacchino Viggiani
2006 ◽  
Vol 54 (2) ◽  
pp. 191-196 ◽  
Author(s):  
S.A. McDonald ◽  
L.C.R. Schneider ◽  
A.C.F. Cocks ◽  
P.J. Withers

Solid Earth ◽  
2016 ◽  
Vol 7 (2) ◽  
pp. 651-658 ◽  
Author(s):  
Wolf-Achim Kahl ◽  
Christian Hansen ◽  
Wolfgang Bach

Abstract. A new flow-through reaction cell consisting of an X-ray-transparent semicrystalline thermoplastic has been developed for percolation experiments. Core holder, tubing and all confining parts are constructed using PEEK (polyetheretherketone) to allow concomitant surveillance of the reaction progress by X-ray microtomography (μ-CT). With this cell setup, corrosive or oversaturated fluids can be forced through rock cores (up to ∅ 19 mm) or powders at pressures up to 100 bar and temperatures up to 200 °C. The reaction progress of the experiment can be monitored without dismantling the sample from the core holder. The combination of this flow-through reaction cell setup with a laboratory X-ray μ-CT system facilitates on-demand monitoring of the reaction progress of (long-term) hydrothermal experiments in the own laboratory, keeping interruption times as short as possible. To demonstrate both the suitability of the cell construction material for X-ray imaging purposes and the experimental performance of the flow-through system, we report the virtually non-existent bias of the PEEK cell setup with distinctive X-ray observations (e.g., differing states of pore fillings: air vs. fluid; detection of delicate fabric elements: filigree zeolite crystals overgrowing weathered muscovite), and the monitoring of the gypsum/anhydrite transition as a case study of a 4-D fabric evolution.


2016 ◽  
Author(s):  
Wolf-Achim Kahl ◽  
Christian Hansen ◽  
Wolfgang Bach

Abstract. A new flow-through reaction cell consisting of an X-ray transparent semicrystalline thermoplastic has been developed for percolation experiments. Core holder, tubing and all confining parts are designed of PEEK (polyetheretherketone) to allow concomitant surveillance of the reaction progress by X-ray microtomography (μ-CT). With this cell setup, corrosive or oversaturated fluids can be forced through rock cores (up to ∅ 19 mm) or powders at pressures up to 100 bars and temperatures up to 200 °C. The reaction progress of the experiment can be monitored without dismantling the sample from the core holder. The combination of this flow-through reaction cell setup with a laboratory X-ray μ-CT system facilitates on-demand monitoring of the reaction progress of (long-term) hydrothermal experiments in the own laboratory, keeping interruption times as short as possible. To demonstrate both the suitability of the cell construction material for X-ray imaging purposes and the experimental performance of the flow-through system, we report the virtually non-existent bias of the PEEK cell setup with distinctive X-ray observations (e. g., differing states of pore fillings: air vs. fluid; detection of delicate fabric elements: filigree zeolitic crystals overgrowing weathered muscovite), and the monitoring of the gypsum/anhydrite transition as a case study of a 4D fabric evolution.


2017 ◽  
Vol 22 (2) ◽  
pp. 49-56
Author(s):  
Selam Waktola ◽  
Andre Bieberle ◽  
Frank Barthel ◽  
Martina Bieberle ◽  
Uwe Hampel ◽  
...  

Abstract This paper presents an application of an ultrafast electron beam X-ray CT scanner for investigating the gravitational flow behavior of granulates through cylindrical silo model. The CT scanner allows obtaining crosssectional images of the granular material distribution with a spatial resolution of approximately 1 mm and a time resolution of 2 kHz. In order to conduct a deep analysis of the granular flow concentration changes, two image processing algorithm steps were applied. The first step deals with preprocessing and re-centering stacks of raw images. The second step divides the preprocessed image into several concentric rings and calculates the mean value to study radial concentration changes. Independent analysis of granular concentration in each ring provides useful knowledge to study the silo discharging during mass flow and funnel flow.


2019 ◽  
Vol 92 ◽  
pp. 03001
Author(s):  
Max Wiebicke ◽  
Edward Andò ◽  
Ivo Herle ◽  
Gioacchino Viggiani

The behaviour of granular materials upon load reversal is not yet fully understood. In order to experimentally reveal the microstructure of a specimen subjected to load-unload cycles, a triaxial compression test on lentils is carried out in the x-ray scanner. Before analysing the acquired tomographies, a benchmark analysis is conducted to validate the image analysis tools that are used to extract the fabric from these images. The contact fabric evolves strongly with the shearing in the experiment on lentils. However, only very slight changes of the anisotropy within the cycles are observed.


2019 ◽  
Vol 16 (3) ◽  
Author(s):  
Yang Liu ◽  
Duo Zhang ◽  
Xiaoxiao Wang ◽  
Pengqiang Yu ◽  
Wei Hu

2005 ◽  
Vol 42 ◽  
pp. 47-52 ◽  
Author(s):  
Atsushi Miyamoto ◽  
Hitoshi Shoji ◽  
Akira Hori ◽  
Takeo Hondoh ◽  
Henrik B. Clausen ◽  
...  

AbstractTo better understand how ice fabric evolves in polar ice sheets, we use X-ray diffraction to measure ice crystal orientations. X-ray measurement equipment which can measure the orientation of the c axis and a axis of each crystal in a thin section with high measurement accuracy was developed. In this study, we present a-axes orientation distribution of the deep part of the GRIP (Greenland summit) ice core. At some depths, we find an anisotropic distribution of a-axes orientation. Long-term uniaxial compression tests are also carried out on the GRIP ice core to investigate the ice fabric evolution process. The c-axis orientation distribution develops into a stronger single maximum as the strain increases up to about 20% strain. We find that the a axes of each grain also tend to cluster close to nearly a mutual direction. We discuss the development process of ice fabrics, taking into consideration the distribution of the a-axis orientations. It is suggested that these fabrics may be attributed to a local simple shear deformation in the deep part of an ice sheet.


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