scholarly journals X-ray Computed Tomography Investigation of Structures in Opalinus Clay from Large Scale to Small Scale after Mechanical Testing

2016 ◽  
Author(s):  
Annette Kaufhold ◽  
Gerhard Zacher ◽  
Matthias Halisch ◽  
Stephan Kaufhold
Keyword(s):  
Computed Tomography ◽  
Mechanical Testing ◽  
Large Scale ◽  
Scanning Speed ◽  
Data Interpretation ◽  
Radioactive Waste Disposal ◽  
Opalinus Clay ◽  
Small Scale ◽  
X Ray ◽  
X Ray Computed

Abstract. In the past years X-ray Computed Tomography (CT) has became more and more common for geoscientific applications and is used from the µm-scale (e.g. for investigations of micro-fossils or pore scale structures) up to the dm-scale (full drill cores or soil columns). In this paper we present results from CT imaging and mineralogical investigations of an Opalinus Clay core on different scales and different regions of interest, emphasizing especially upon the 3D evaluation and distribution of cracks and their impact upon mechanical testing of such material. Enhanced knowledge of the testing behavior of the Opalinus Clay is of great interest, especially since this material is considered for a long term radioactive waste disposal and storage facility in Switzerland. Hence, results are compared regarding the mineral (i.e. phase) contrast resolution, the spatial resolution, and the overall scanning speed. With this extensive interdisciplinary top-down approach it has been possible to characterize the general fracture propagation in comparison to mineralogical and textural features of the Opalinus Clay. Additionally, and as far as we know, a so called mylonitic zone, located at the intersect of two main fractures, has been observed for the first time for an experimentally deformed Opalinus sample. The multi-scale results are in good accordance to data from naturally deformed Opalinus Clay samples, which enables to perform systematical research under controlled laboratory conditions. Accompanying 3D imaging greatly enhances the capability of data interpretation and assessment of such a material.

scholarly journals X-ray computed tomography investigation of structures in Opalinus Clay from large-scale to small-scale after mechanical testing

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1171-1183 ◽  
Author(s):  
Annette Kaufhold ◽  
Matthias Halisch ◽  
Gerhard Zacher ◽  
Stephan Kaufhold
Keyword(s):  
Computed Tomography ◽  
Mechanical Testing ◽  
Large Scale ◽  
Data Interpretation ◽  
Radioactive Waste Disposal ◽  
Opalinus Clay ◽  
Small Scale ◽  
X Ray ◽  
Scale Down ◽  
X Ray Computed

Abstract. In the past years X-ray computed tomography (CT) has became more and more common for geoscientific applications and is used from the µm-scale (e.g. for investigations of microfossils or pore-scale structures) up to the dm-scale (full drill cores or soil columns). In this paper we present results from CT imaging and mineralogical investigations of an Opalinus Clay core on different scales and different regions of interest, emphasizing especially the 3-D evaluation and distribution of cracks and their impact on mechanical testing of such material. Enhanced knowledge of the testing behaviour of the Opalinus Clay is of great interest, especially since this material is considered for a long-term radioactive waste disposal and storage facility in Switzerland. Hence, results are compared regarding the mineral (i.e. phase) contrast resolution, the spatial resolution, and the overall scanning speed.With this extensive interdisciplinary scale-down approach it has been possible to characterize the general fracture propagation in comparison to mineralogical and textural features of the Opalinus Clay. Additionally, and as far as we know, a so-called mylonitic zone, located at an intersect of two main fractures, has been observed for the first time for an experimentally deformed Opalinus sample. The multi-scale results are in good accordance to data from naturally deformed Opalinus Clay samples, which enables us to perform systematical research under controlled laboratory conditions. Accompanying 3-D imaging greatly enhances the capability of data interpretation and assessment of such a material.

scholarly journals X-ray Computed Tomography Investigation of Structures in Claystone at Large Scale and High Speed

2015 ◽  
Vol 2015 (1) ◽  
pp. 1-2
Author(s):  
Gerhard Zacher ◽  
Thomas Paul ◽  
Annette Kaufhold ◽  
Werner Grasle
Keyword(s):  
Computed Tomography ◽  
High Speed ◽  
Large Scale ◽  
X Ray ◽  
X Ray Computed

scholarly journals X-ray Computed Tomography for the ex-situ mechanical testing and simulation of additively manufactured IN718 samples

2021 ◽  
pp. 102070
Author(s):  
Grzegorz Ziółkowski ◽  
Konrad Gruber ◽  
Emilia Tokarczyk ◽  
Robert Roszak ◽  
Matthias Ziegenhorn
Keyword(s):  
Computed Tomography ◽  
Mechanical Testing ◽  
Ex Situ ◽  
X Ray ◽  
X Ray Computed

scholarly journals How little data is enough? Phase-diagram analysis of sparsity-regularized X-ray computed tomography

2015 ◽  
Vol 373 (2043) ◽  
pp. 20140387 ◽  
Author(s):  
J. S. Jørgensen ◽  
E. Y. Sidky
Keyword(s):  
Computed Tomography ◽  
Phase Diagram ◽  
Large Scale ◽  
Total Variation Regularization ◽  
X Ray ◽  
Standard Tool ◽  
X Ray Computed ◽  
Improved Performance ◽  
Diagram Analysis ◽  
Theoretical Results

We introduce phase-diagram analysis, a standard tool in compressed sensing (CS), to the X-ray computed tomography (CT) community as a systematic method for determining how few projections suffice for accurate sparsity-regularized reconstruction. In CS, a phase diagram is a convenient way to study and express certain theoretical relations between sparsity and sufficient sampling. We adapt phase-diagram analysis for empirical use in X-ray CT for which the same theoretical results do not hold. We demonstrate in three case studies the potential of phase-diagram analysis for providing quantitative answers to questions of undersampling. First, we demonstrate that there are cases where X-ray CT empirically performs comparably with a near-optimal CS strategy, namely taking measurements with Gaussian sensing matrices. Second, we show that, in contrast to what might have been anticipated, taking randomized CT measurements does not lead to improved performance compared with standard structured sampling patterns. Finally, we show preliminary results of how well phase-diagram analysis can predict the sufficient number of projections for accurately reconstructing a large-scale image of a given sparsity by means of total-variation regularization.

scholarly journals Benefits of applying X-ray computed tomography in bentonite based material research focussed on geological disposal of radioactive waste

2020 ◽  
Vol 27 (31) ◽  
pp. 38407-38421 ◽  
Author(s):  
Heini Maria Reijonen ◽  
Jukka Kuva ◽  
Pasi Heikkilä
Keyword(s):  
Computed Tomography ◽  
Radioactive Waste ◽  
Radioactive Waste Disposal ◽  
Material Research ◽  
X Ray ◽  
Spatial Coverage ◽  
X Ray Computed ◽  
Third Dimension ◽  
High Level

Abstract Bentonite-based geomaterials are included in the designs of geological repository planning in most countries, especially in high-level radioactive waste disposal. Physical integrity of the bentonite sealant is key in assuring its hydraulic and retention properties, which affect the long-term performance of the repositories. Examination of the internal textures and structures of bentonite has been challenging until recently. Here, X-ray computed tomography (XCT) is applied to improve the textural and structural characterization of natural and man-made bentonite samples. Based on these initial analyses, clear benefits have been identified compared with conventional bentonite research methods. First, applying XCT prior to destructive analytical methods provides means to distinguish secondary features or in situ textures. It allows to eliminate false interpretations due to sample deformation and guides subsampling. Second, XCT images add the third dimension to analyses, allowing larger spatial coverage in less time. Overall, findings support the application of XCT for reducing uncertainties related to physical characterization of bentonite samples, both natural and industrial. They also show that XCT has potential to be developed to support quality assurance processes for bentonite sealant manufacturing.

scholarly journals First ptychographic X-ray computed tomography experiment on the NanoMAX beamline

2020 ◽  
Vol 53 (6) ◽  
pp. 1444-1451
Author(s):  
Maik Kahnt ◽  
Simone Sala ◽  
Ulf Johansson ◽  
Alexander Björling ◽  
Zhimin Jiang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Scanning Speed ◽  
Fourth Generation ◽  
X Ray ◽  
Radiation Sources ◽  
X Ray Computed ◽  
Synchrotron Light ◽  
Set Up

Ptychographic X-ray computed tomography is a quantitative three-dimensional imaging technique offered to users of multiple synchrotron radiation sources. Its dependence on the coherent fraction of the available X-ray beam makes it perfectly suited to diffraction-limited storage rings. Although MAX IV is the first, and so far only, operating fourth-generation synchrotron light source, none of its experimental stations is currently set up to offer this technique to its users. The first ptychographic X-ray computed tomography experiment has therefore been performed on the NanoMAX beamline. From the results, information was gained about the current limitations of the experimental setup and where attention should be focused for improvement. The extracted parameters in terms of scanning speed, size of the imaged volume and achieved resolutions should provide a baseline for future users designing nano-tomography experiments on the NanoMAX beamline.

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