scholarly journals Visualization and quantification of capillary drainage in the pore space of laminated sandstone by a porous plate method using differential imaging X-ray microtomography

2017 ◽  
Vol 53 (8) ◽  
pp. 7457-7468 ◽  
Author(s):  
Qingyang Lin ◽  
Branko Bijeljic ◽  
Holger Rieke ◽  
Martin J. Blunt
Keyword(s):  
Pore Space ◽  
Porous Plate ◽  
Plate Method ◽  
X Ray ◽  
Differential Imaging ◽  
Capillary Drainage

Structural aspects of the hisingerite-neotocite series

Clay Minerals ◽  
1983 ◽  
Vol 18 (1) ◽  
pp. 21-31 ◽  
Author(s):  
R. A. Eggleton ◽  
J. H. Pennington ◽  
R. S. Freeman ◽  
I. M. Threadgold
Keyword(s):  
Function Analysis ◽  
Pore Space ◽  
Hollow Spheres ◽  
X Ray ◽  
Broken Hill ◽  
Transmission Electron ◽  
X Ray Absorption ◽  
Interconnected Pore ◽  
Intermediate Member ◽  
Structural Aspects

AbstractTransmission electron microscopy, X-ray radial distribution function analysis, chemical analysis, X-ray absorption edge spectroscopy, and Mössbauer spectroscopy combine to confirm an amorphous or gel structure for minerals of the hisingerite-neotocite series: (Fe,Mn)0.8SiO3.1.2H2O. A framework of (Fe,Mn)O6 octahedra and [SiO4] tetrahedra form hollow spheres, 50–100 Å in diameter, cross-bonded into a physically isotropic solid with as much as 10% interconnected pore space. The outer 10–20 Å of the spheres has a rudimentary structure, possibly marking the onset of segregation into Si-rich and (Fe,Mn)-rich layers. The Broken Hill mineral ‘sturtite’ is an intermediate member of the hisingerite-neotocite series.

scholarly journals Reconstruction and Analysis of Tight Sandstone Digital Rock Combined with X-Ray CT Scanning and Multiple-Point Geostatistics Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yun Lei
Keyword(s):  
Pore Space ◽  
Full Range ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Multiple Point ◽  
Tight Sandstone ◽  
Sandstone Sample ◽  
X Ray ◽  
Digital Rock ◽  
Experimental Values

Unconventional rocks such as tight sandstone and shale usually develop multiscale complex pore structures, with dimensions ranging from nanometers to millimeters, and the full range can be difficult to characterize for natural samples. In this paper, we developed a new hybrid digital rock construction approach to mimic the pore space of tight sandstone by combining X-ray CT scanning and multiple-point geostatistics algorithm (MPGA). First, a three-dimensional macropore digital rock describing the macroscopic pore structure of tight sandstone was constructed by micro-CT scanning. Then, high-resolution scanning electron microscopy (SEM) was performed on the tight sandstone sample, and the three-dimensional micropore digital rock was reconstructed by MPGA. Finally, the macropore digital rock and the micropore digital rock were superimposed into the full-pore digital rock. In addition, the nuclear magnetic resonance (NMR) response of digital rocks is simulated using a random walk method, and seepage simulation was performed by the lattice Boltzmann method (LBM). The results show that the full-pore digital rock has the same anisotropy and good connectivity as the actual rock. The porosity, NMR response, and permeability are in good agreement with the experimental values.

scholarly journals Motion of dust particles in dry snow under temperature gradient metamorphism

2019 ◽  
Vol 13 (9) ◽  
pp. 2345-2359 ◽  
Author(s):  
Pascal Hagenmuller ◽  
Frederic Flin ◽  
Marie Dumont ◽  
François Tuzet ◽  
Isabel Peinke ◽  
...  
Keyword(s):  
Time Series ◽  
Temperature Gradient ◽  
Pore Space ◽  
Observational Evidence ◽  
Climate Forcing ◽  
Dust Particles ◽  
Snow Surface ◽  
X Ray ◽  
Arctic Regions ◽  
Radiative Impact

Abstract. The deposition of light-absorbing particles (LAPs) such as mineral dust and black carbon on snow is responsible for a highly effective climate forcing, through darkening of the snow surface and associated feedbacks. The interplay between post-depositional snow transformation (metamorphism) and the dynamics of LAPs in snow remains largely unknown. We obtained time series of X-ray tomography images of dust-contaminated samples undergoing dry snow metamorphism at around −2 ∘C. They provide the first observational evidence that temperature gradient metamorphism induces dust particle motion in snow, while no movement is observed under isothermal conditions. Under temperature gradient metamorphism, dust particles can enter the ice matrix due to sublimation–condensation processes and spread down mainly by falling into the pore space. Overall, such motions might reduce the radiative impact of dust in snow, in particular in arctic regions where temperature gradient metamorphism prevails.

Study on Imaging Arsenic Aggregates in Porous Media by X-Ray Difference Micro-Tomography

2011 ◽  
Vol 356-360 ◽  
pp. 2362-2366
Author(s):  
Dao Ping Peng ◽  
Tao Huang ◽  
Chun Xiao Meng
Keyword(s):  
Porous Media ◽  
Background Noise ◽  
3D Visualization ◽  
Pore Space ◽  
Fluvial Sediments ◽  
X Ray ◽  
The Media ◽  
Micro Tomography ◽  
Grain Surface ◽  
Post Deposition

In order to investigate the change of internal structure of porous media caused by arsenic deposition, X-ray difference micro-tomography was used to characterize the distribution of arsenic aggregates within porous media by scanning a series of arsenic samples prepared in the laboratory and arsenic-rich fluvial sediments from the Río Loa in Chile. After image processing, background noise in the tomograms was reduced and arsenic information was enhanced. Then the processed images were used to generate 3D spatial distribution datasets of arsenic in the media. Tools like Avizo6 and Blob3D were used to reconstruct and visualize the 3D datasets. 3D visualization showed that arsenic accumulated in the pore space and grain surface; arsenic aggregates of different sizes had distinctly different morphologies, which small aggregates tended to be spherical while big aggregates were relatively flat. These results show that difference micro-tomography can be used to observe the pre- and post-deposition structure of porous media, without any destruction to the samples.

scholarly journals Combining spectral induced polarization with X-ray tomography to investigate the importance of DNAPL geometry in sand samples

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. E173-E188 ◽  
Author(s):  
Sara Johansson ◽  
Matteo Rossi ◽  
Stephen A. Hall ◽  
Charlotte Sparrenbom ◽  
David Hagerberg ◽  
...  
Keyword(s):  
Image Analysis ◽  
Pore Space ◽  
Total Concentration ◽  
Data Interpretation ◽  
Induced Polarization ◽  
X Ray ◽  
Fine Grained ◽  
Surface Areas ◽  
Spectral Induced Polarization ◽  
The Individual

Although many studies have been performed to investigate the spectral induced polarization (SIP) response of nonaqueous phase liquid (NAPL)-contaminated soil samples, there are still many uncertainties in the interpretation of the data. A key issue is that altered pore space geometries due to the presence of a NAPL phase will change the measured IP spectra. However, without any information on the NAPL distribution in the pore space, assumptions are necessary for the SIP data interpretation. Therefore, experimental data of SIP signals directly associated with different NAPL distributions are needed. We used high-resolution X-ray tomography and 3D image processing to quantitatively assess NAPL distributions in samples of fine-grained sand containing different concentrations of tetrachloroethylene and link this to SIP measurements on the same samples. The total concentration of the sample constituents as well as the volumes of the individual NAPL blobs were calculated and used for the interpretation of the associated SIP responses. The X-ray tomography and image analysis showed that the real sample properties (porosity and NAPL distributions) differed from the targeted ones. Both contaminated samples contained less NAPL than expected from the manual sample preparation. The SIP results showed higher real conductivity and lower imaginary conductivity in the contaminated samples compared to a clean sample. This is interpreted as an effect of increased surface conductivity along interconnected NAPL blobs and decreased surface areas in the samples due to NAPL blobs larger than and enclosing grains. We conclude that the combination of SIP, X-ray tomography, and image analysis is a very promising approach to achieve a better understanding of the measured SIP responses of NAPL-contaminated samples.

X-ray Micro-CT: How Soil Pore Space Description Can Be Altered by Image Processing

2017 ◽  
Vol 17 (1) ◽  
pp. 160049 ◽  
Author(s):  
Sarah Smet ◽  
Erwan Plougonven ◽  
Angélique Leonard ◽  
Aurore Degré ◽  
Eléonore Beckers
Keyword(s):  
Image Processing ◽  
Pore Space ◽  
Micro Ct ◽  
X Ray ◽  
Soil Pore Space ◽  
Space Description

Fabrication and mechanical properties of Al/Al2O3 composite bodies by reactive infiltration of molten Al into SiO2 preform

2000 ◽  
Vol 15 (11) ◽  
pp. 2314-2321 ◽  
Author(s):  
Noboru Yoshikawa ◽  
Singo Funahashi ◽  
Shoji Taniguchi ◽  
Atsushi Kikuchi
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Sintering Temperature ◽  
Pore Space ◽  
Pressure Infiltration ◽  
X Ray ◽  
Reactive Infiltration ◽  
Pore Size Distributions ◽  
Different Temperatures ◽  
Si Content

Al/Al2O3 composites were fabricated by a displacement reaction between SiO2 and molten Al. In this study, fabrication of Al/Al2O3 composites was attempted by means of reactive infiltration to provide variation of their mechanical properties. SiO2 preforms having various porosities and pore size distributions were prepared by sintering the powder at different temperatures between 1273 and 1723 K. Molten Al was infiltrated at 1373 K without application of pressure. Infiltration kinetics were studied and the microstructures of the composite bodies were observed by means of scanning electron microscopy (with energy dispersive x-ray microanalysis), wave dispersive x-ray microanalysis, and x-ray diffractions. The infiltrated specimens were mainly composed of Al and α–Al2O3 phases, and the Si content was less than 5 at.%. Volume fraction of Al phase in the composite bodies was not altered very much with the porosities of the SiO2 preforms because of the difficulty in filling out the entire pore space. Properties and microstructures of Al/Al2O3 composites, however, were dependent on the sintering temperature of the SiO2 preforms. In the case of low sintering temperature, a thick Al channel existed, which deformed upon compression. In the case of high sintering temperature, the microstructure became homogeneous and had thinner Al channels. The composite bodies became brittle. The deformation behavior was shown to be changed from ductile to brittle as an increase of the sintering temperature of the preforms.

scholarly journals Pore-Scale Imaging of the Oil Cluster Dynamic during Drainage and Imbibition Using In Situ X-Ray Microtomography

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Junjian Li ◽  
Yajun Gao ◽  
Hanqiao Jiang ◽  
Yang Liu ◽  
Hu Dong
Keyword(s):  
Specific Surface ◽  
Capillary Pressure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Space ◽  
Relative Volume ◽  
Pore Scale ◽  
X Ray ◽  
Cluster Dynamic ◽  
Remaining Oil

We imaged water-wet and oil-wet sandstones under two-phase flow conditions for different flooding states by means of X-ray computed microtomography (μCT) with a spatial resolution of 2.1 μm/pixel. We systematically study pore-scale trapping of the nonwetting phase as well as size and distribution of its connected clusters and disconnected globules. We found a lower Sor, 19.8%, for the oil-wet plug than for water-wet plug (25.2%). Approximate power-law distributions of the water and oil cluster sizes were observed in the pore space. Besides, the τ value of the wetting phase gradually decreased and the nonwetting phase gradually increased during the core-flood experiment. The remaining oil has been divided into five categories; we explored the pore fluid occupancies and studied size and distribution of the five types of trapped oil clusters during different drainage stage. The result shows that only the relative volume of the clustered oil is reduced, and the other four types of remaining oil all increased. Pore structure, wettability, and its connectivity have a significant effect on the trapped oil distribution. In the water sandstone, the trapped oil tends to occupy the center of the larger pores during the water imbibition process, leading to a stable specific surface area and a gradually decreasing oil capillary pressure. Meanwhile, in oil-wet sandstone, the trapped oil blobs that tend to occupy the pores corner and attach to the walls of the pores have a large specific surface area, and the change of the oil capillary pressure was not obvious. These results have revealed the well-known complexity of multiphase flow in rocks and preliminarily show the pore-level displacement physics of the process.

scholarly journals Differential Imaging of [Fe X] in IC 443

1988 ◽  
Vol 101 ◽  
pp. 407-410
Author(s):  
Larry Brown ◽  
Bruce E. Woodgate ◽  
Robert Petre
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
Temperature Region ◽  
Supernova Remnant ◽  
Coronal Line ◽  
X Ray ◽  
Imaging Camera ◽  
Differential Imaging ◽  
Einstein Observatory ◽  
Gas Pressures

AbstractThis paper presents images of two areas of the supernova remnant IC443 showing emission from the [Fe X] 6374Å red coronal line taken with an emission line differential imaging camera. The areas are in the vicinity of strong soft X-ray emission as observed with the Einstein Observatory. The [Fe X] emission is patchy on the scale of seconds of arc. For the highest emission regions we find an electron density of approximately 100 cm−3 and gas pressures of 108cm−3K. No correlation is found between the X-ray and [Fe X] knots, and the results support a clumpy, multi-temperature region where the [Fe X] knots are balanced between collapse and evaporation.

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