scholarly journals Quantification of Lithological Heterogeneity Within Opalinus Clay: Toward a Uniform Subfacies Classification Scheme Using a Novel Automated Core Image Recognition Tool

2021 ◽  
Vol 9 ◽  
Author(s):  
Bruno Lauper ◽  
Géraldine N. Zimmerli ◽  
David Jaeggi ◽  
Gaudenz Deplazes ◽  
Stephan Wohlwend ◽  
...  
Keyword(s):  
Classification Scheme ◽  
Biological Properties ◽  
Opalinus Clay ◽  
Rock Properties ◽  
Small Scale ◽  
X Ray ◽  
Northern Switzerland ◽  
Sedimentary Characteristics ◽  
Mont Terri ◽  
Lithological Heterogeneity

The Opalinus Clay is notable in Switzerland as being the selected host rock for deep geological disposal of radioactive waste. Since the early 1990’s, this argillaceous mudstone formation of Jurassic age has been intensively studied within the framework of national and international projects to characterize its geological, hydrological, mechanical, thermal, chemical, and biological properties. While there is no formal stratigraphic subdivision, the Opalinus Clay lithology is classically divided into several, dam- to m-scale sub-units (or facies), depending on location. Recent multi-proxy studies (combining petrographic, petrophysical, geochemical, and mineralogical analyses) have however demonstrated that high, intra-facies, lithological heterogeneity occurs at the dm- to cm-scale. To constrain this small-scale heterogeneity into distinct lithological units (subfacies), the present study aims at defining and presenting a convenient subfacies classification scheme covering the overall Opalinus Clay lithology across northern Switzerland. Petrographic (macro- and microfacies), mineralogical (X-ray diffraction) and textural (image analysis, machine learning and 3D X-ray computed tomography) analyses are performed on diverse drill cores from the Mont Terri rock laboratory (northwestern Switzerland), and results are extended further to the east (Riniken, Weiach, and Benken). Most of the investigated Opalinus Clay can be described by the use of five distinctive subfacies types (SF1 to SF5), which are visually and quantitatively distinguishable by texture (grain size, bedding, fabric, and color) and composition (nature and mineralogy of components). The five subfacies types can be further refined by additional attributes and sedimentary characteristics (biogenic, diagenetic, and structural). Eventually, the widespread and consistent use of standardized Opalinus Clay subfacies types provides the means to harmonize petrographic descriptions within multidisciplinary research projects, enhance reproducibility of in situ experiments, and further evidence the tight relations between lithology and various rock properties.

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.

Tritium and Iodide Diffusion through Opalinus Clay

2000 ◽  
Vol 663 ◽  
Author(s):  
A. Yllera de Llano ◽  
M. Mingarro Sainz-Ezquerra ◽  
M. García Gutiérrez
Keyword(s):  
Methodological Approach ◽  
Time Lag ◽  
Tritiated Water ◽  
Effective Diffusion ◽  
Opalinus Clay ◽  
Small Scale ◽  
Northwestern Part ◽  
Large Variability ◽  
Rock Laboratory ◽  
Mont Terri

ABSTRACTThe International Mont Terri Project [1, 2] started in 1995 under the patronage of the Swiss National Hydrological and Geological Survey (SNHGS), and has the authorization of the République et Canton du Jura. The underground rock laboratory is located at the northwestern part of Switzerland (Canton Jura), in and beside the reconnaissance gallery of the Mont Terri motorway tunnel, one of the several tunnels of the A16 “Transjurane” motorway. The depth of overburden above the rock laboratory is approximately 300 meters.The project is aimed to investigate the geological, hydrogeological, geochemical and rock mechanical properties of the Opalinus Clay for assessing the feasibility and safety of a repository for radioactive waste placed in this type of host rock. One of the issues under study is radionuclide migration by diffusion through clays. As a part of this investigation, an interlaboratory comparison on small-scale diffusion experiments was carried out by three research laboratories: AEA Technology (UK), SCK·CEN (Belgium) and CIEMAT (Spain). The radionuclides investigated were tritium and iodine. This paper concerns to the methodological approach and results of the experiments undertaken by CIEMAT.The effective diffusion coefficients were measured for tritiated water and iodine (as I-), resulting larger for tritium [(1.7±0.4)×10−11 m2/s] than for iodide [(2.7±0.3)×10−12 m2/s]. The porosity available for diffusion was calculated by using the time-lag method, but some results seemed unrealistic and showed a large variability. In general, tritium exhibited higher values of porosity than iodide (17 to 26% and 12 to 17%, respectively), which were consistent with the anion exclusion affecting the distribution of iodide into the clay pores.

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 In-situ diffusion of HTO, 22Na+, Cs+ and I- in Opalinus Clay at the Mont Terri underground rock laboratory

2004 ◽  
Vol 92 (9-11) ◽  
Author(s):  
Luc R. Van Loon ◽  
P. Wersin ◽  
J. M. Soler ◽  
J. Eikenberg ◽  
Th. Gimmi ◽  
...  
Keyword(s):  
Research Laboratory ◽  
Opalinus Clay ◽  
Small Scale ◽  
Diffusion Data ◽  
Rock Laboratory ◽  
In Situ Diffusion ◽  
Mont Terri ◽  
Underground Research Laboratory ◽  
Diffusion Properties

SummaryThe diffusion properties of the Opalinus Clay were studied in the underground research laboratory at Mont Terri (Canton Jura, Switzerland) and the results were compared with diffusion data measured in the laboratory on small-scale samples. The diffusion of HTO,

scholarly journals QPOs in compact binaries from small scale eruptions in an inner magnetized disk

2020 ◽  
Author(s):  
Nicolas Scepi ◽  
Mitchell C Begelman ◽  
Jason Dexter
Keyword(s):  
Rapid Heating ◽  
Small Scale ◽  
Type B ◽  
Periodic Oscillations ◽  
X Ray ◽  
Compact Binaries ◽  
Heating And Cooling ◽  
Low Mass ◽  
X Ray Binaries ◽  
Standard Disk

Abstract Dwarf novæ (DNe) and low mass X-ray binaries (LMXBs) are compact binaries showing variability on time scales from years to less than seconds. Here, we focus on explaining part of the rapid fluctuations in DNe, following the framework of recent studies on the monthly eruptions of DNe that use a hybrid disk composed of an outer standard disk and an inner magnetized disk. We show that the ionization instability, that is responsible for the monthly eruptions of DNe, is also able to operate in the inner magnetized disk. Given the low density and the fast accretion time scale of the inner magnetized disk, the ionization instability generates small, rapid heating and cooling fronts propagating back and forth in the inner disk. This leads to quasi-periodic oscillations (QPOs) with a period of the order of 1000 s. A strong prediction of our model is that these QPOs can only develop in quiescence or at the beginning/end of an outburst. We propose that these rapid fluctuations might explain a subclass of already observed QPOs in DNe as well as a, still to observe, subclass of QPOs in LMXBs. We also extrapolate to the possibility that the radiation pressure instability might be related to Type B QPOs in LMXBs.

scholarly journals Non-Invasive Technical Investigation of English Portrait Miniatures Attributed to Nicholas Hilliard and Isaac Oliver

Heritage ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 1165-1181
Author(s):  
Flavia Fiorillo ◽  
Lucia Burgio ◽  
Christine Slottved Kimbriel ◽  
Paola Ricciardi
Keyword(s):  
Fluorescence Spectroscopy ◽  
Scientific Methodology ◽  
Small Scale ◽  
Artistic Practice ◽  
X Ray ◽  
Non Invasive ◽  
Miniature Painting ◽  
Entire Career ◽  
Similarities And Differences ◽  
Victoria And Albert Museum

This study presents the results of the technical investigation carried out on several English portrait miniatures painted in the 16th and 17th century by Nicholas Hilliard and Isaac Oliver, two of the most famous limners working at the Tudor and Stuart courts. The 23 objects chosen for the analysis, spanning almost the entire career of the two artists, belong to the collections of the Victoria and Albert Museum (London) and the Fitzwilliam Museum (Cambridge). A non-invasive scientific methodology, comprising of stereo and optical microscopies, Raman microscopy, and X-ray fluorescence spectroscopy, was required for the investigation of these small-scale and fragile objects. The palettes and working techniques of the two artists were characterised, focusing in particular on the examination of flesh tones, mouths, and eyes. These findings were also compared to the information written in the treatises on miniature painting circulating during the artists’ lifetime. By identifying the materials and techniques most widely employed by the two artists, this study provides information about similarities and differences in their working methods, which can help to understand their artistic practice as well as contribute to matters of attribution.

scholarly journals Small scale materials behavior from X-ray microdiffraction and imaging: Part II

JOM ◽  
2011 ◽  
Vol 63 (7) ◽  
pp. 60-60 ◽  
Author(s):  
Rozaliya I. Barabash
Keyword(s):  
Small Scale ◽  
X Ray ◽  
Materials Behavior
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