scholarly journals Transport of Palladium Nanoparticles in Porous Media of Varying Grain Size with Synchrotron X-Ray Computerized Tomography

2020 ◽  
Author(s):  
Emily Saurette ◽  
Adam Lentz ◽  
Stuart Linley ◽  
Frank Gu ◽  
Mark Rivers ◽  
...  
Keyword(s):  
Grain Size ◽  
Porous Media ◽  
Computerized Tomography ◽  
Palladium Nanoparticles ◽  
X Ray

Contaminant migration in unsaturated porous media using X-ray computerized tomography (CT)

2013 ◽  
Vol 69 (5) ◽  
pp. 953-959 ◽  
Author(s):  
Nian Qing Zhou ◽  
Shan Zhao ◽  
Wei Song ◽  
Jun Otani
Keyword(s):  
Porous Media ◽  
Computerized Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Silica Sand ◽  
Unsaturated Porous Media ◽  
Contaminant Migration ◽  
X Ray ◽  
Before And After ◽  
Unsaturated Zones

Landfills are usually located in unsaturated zones. Contaminant leaking can easily infiltrate groundwater through these porous media and contribute to groundwater pollution. The main objective of this work is to study the leachate migration in unsaturated porous media using X-ray computerized tomography (CT) and image-processing software. Silica sand and Yamazuna sand (collected from Japan) with different particle sizes are considered. Potassium iodide (KI) solution is used as a contaminant and injected into sand specimens at appropriate rates. The specimens are scanned at each cross section before and after contaminant injection by X-ray CT. Subsequently, all CT images are transformed into mean CT values by Image J software. VGStudio software is then used to reconstruct the subtracted images into three-dimensional images. The results indicate that vertical migration is dominant in uniform sand and horizontal migration is the main behavior in well-graded sand. Meanwhile, it is also confirmed that CT scanning is an effective technology to study contaminant migration in unsaturated porous media with different grain sizes.

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

Water capillary absorption in porous media in different wettability conditions studied by quantitative MRI and X-ray CT

2007 ◽  
Vol 25 (4) ◽  
pp. 558-559
Author(s):  
M. Gombia ◽  
V. Bortolotti ◽  
P. Fantazzini ◽  
M. Camaiti ◽  
T. Schillaci ◽  
...  
Keyword(s):  
Porous Media ◽  
Quantitative Mri ◽  
Capillary Absorption ◽  
X Ray

Experimental investigation of solute transport in variably saturated porous media using x-ray computed tomography

2021 ◽  
Vol 33 (7) ◽  
pp. 076610
Author(s):  
Chunwei Zhang ◽  
Yun She ◽  
Yingxue Hu ◽  
Zijing Li ◽  
Weicen Wang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Experimental Investigation ◽  
Porous Media ◽  
Solute Transport ◽  
Saturated Porous Media ◽  
X Ray ◽  
X Ray Computed

Evaluating drilling fluid infiltration in porous media – Comparing NMR, gravimetric, and X-ray CT scan methods

2021 ◽  
Vol 198 ◽  
pp. 108242
Author(s):  
Badr S. Bageri ◽  
Abdulrauf R. Adebayo ◽  
Jaber Al Jaberi ◽  
Shirish Patil ◽  
Rahul B. Salin
Keyword(s):  
Porous Media ◽  
Ct Scan ◽  
Drilling Fluid ◽  
X Ray ◽  
Fluid Infiltration

scholarly journals Hyperpolarised xenon MRI and time-resolved X-ray computed tomography studies of structure-transport relationships in hierarchical porous media

2021 ◽  
Vol 405 ◽  
pp. 126750
Author(s):  
Fraser Hill-Casey ◽  
Thomas Hotchkiss ◽  
Katharine A. Hardstone ◽  
Iain Hitchcock ◽  
Vladimir Novak ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Porous Media ◽  
Time Resolved ◽  
X Ray ◽  
Hierarchical Porous ◽  
X Ray Computed ◽  
Hierarchical Porous Media

scholarly journals Preparation of high-entropy carbides by different sintering techniques

2021 ◽  
Vol 56 (19) ◽  
pp. 11237-11247 ◽  
Author(s):  
Johannes Pötschke ◽  
Manisha Dahal ◽  
Mathias Herrmann ◽  
Anne Vornberger ◽  
Björn Matthey ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Vacuum Sintering ◽  
X Ray ◽  
High Entropy ◽  
Mean Grain Size ◽  
The Mean ◽  
Gas Pressure Sintering ◽  
Hardness Values

AbstractDense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

scholarly journals Structural Changes in French VF Treatment Wetland Porous Media during the Rest Period: An Ex Situ Study Using X-ray Tomography

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 389
Author(s):  
German Dario Martinez-Carvajal ◽  
Laurent Oxarango ◽  
Jérôme Adrien ◽  
Pascal Molle ◽  
Nicolas Forquet
Keyword(s):  
Porous Media ◽  
Structural Changes ◽  
Rest Period ◽  
Treatment Wetlands ◽  
Ex Situ ◽  
Initial Value ◽  
Treatment Wetland ◽  
X Ray ◽  
The Impact ◽  
Deposit Layer

Clogging constitutes a major operational issue for treatment wetlands. The rest period is a key feature of French Vertical Flow (VF) treatment wetlands and serves to mitigate clogging. An ex-situ drying experiment was performed to mimic the rest period and record structural changes in the porous media using X-ray Computed Tomography (CT). Samples containing the deposit and gravel layers of a first stage French VF treatment wetland were extracted and left to dry in a control environment. Based on CT scans, three phases were identified (voids, biosolids, and gravels). The impact of the rest period was assessed by means of different pore-scale variables. Ultimately, the volume of biosolids had reduced to 58% of its initial value, the deposit layer thickness dropped to 68% of its initial value, and the void/biosolid specific surface area ratio increased from a minimum value of 1.1 to a maximum of 4.2. Cracks greater than 3 mm developed at the uppermost part of the deposit layer, while, in the gravel layer, the rise in void volume corresponds to pores smaller than 2 mm in diameter. Lastly, the air-filled microporosity is estimated to have increased by 0.11 v/v.

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