scholarly journals Orientational mapping of minerals in Pierre shale using X-ray diffraction tensor tomography

IUCrJ ◽  
2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Fredrik K. Mürer ◽  
Aldritt Scaria Madathiparambil ◽  
Kim Robert Tekseth ◽  
Marco Di Michiel ◽  
Pierre Cerasi ◽  
...  
Keyword(s):  
Orientation Distribution ◽  
Bedding Plane ◽  
Structural Features ◽  
Spatial Density ◽  
Structural Description ◽  
X Ray Diffraction ◽  
Crystallite Orientation ◽  
X Ray ◽  
Tensor Tomography ◽  
Pierre Shale

Shales have a complex mineralogy with structural features spanning several length scales, making them notoriously difficult to fully understand. Conventional attenuation-based X-ray computed tomography (CT) measures density differences, which, owing to the heterogeneity and sub-resolution features in shales, makes reliable interpretation of shale images a challenging task. CT based on X-ray diffraction (XRD-CT), rather than intensity attenuation, is becoming a well established technique for non-destructive 3D imaging, and is especially suited for heterogeneous and hierarchical materials. XRD patterns contain information about the mineral crystal structure, and crucially also crystallite orientation. Here, we report on the use of orientational imaging using XRD-CT to study crystallite-orientation distributions in a sample of Pierre shale. Diffraction-contrast CT data for a shale sample measured with its bedding-plane normal aligned parallel to a single tomographic axis perpendicular to the incoming X-ray beam are discussed, and the spatial density and orientation distribution of clay minerals in the sample are described. Finally, the scattering properties of highly attenuating inclusions in the shale bulk are studied, which are identified to contain pyrite and clinochlore. A path forward is then outlined for systematically improving the structural description of shales.

Mechanical and Structural Properties of Superhard TiAlSiN Coatings Deposited by Arc Ion Plating of Cylindrical Cathode

2014 ◽  
Vol 783-786 ◽  
pp. 1426-1431
Author(s):  
Wang Ryeol Kim ◽  
Min Chul Kwon ◽  
Jung Hoon Lee ◽  
Uoo Chang Jung ◽  
Won Sub Chung
Keyword(s):  
Structural Properties ◽  
Nitrogen Pressure ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Plating ◽  
Arc Current ◽  
Cathode Arc ◽  
Cathodic Arc ◽  
Tialsin Coating

TiAlSiN coatings were deposited on WC-Co metal by using a cathodic arc ion deposition method of cylindrical cathode. We used Ti / Al (50 / 50 at.%) arc target and silicon sputter target. The influence of the nitrogen pressure, TiAl cathode arc current, bias voltage, and deposition temperature on the mechanical and the structural properties of the films were investigated. The structural features of the films were investigation in detail using X-ray diffraction. And coatings were characterized by means of FE-SEM, nanoindentation, Scratch tester, Tribology tester, XRD and XPS. The hardness of the film reached 43 GPa at the cathode arc current of 230 A and decreased with a further increase of the arc current. And the adhesion of the film reached 34 N. The results showed that the TiAlSiN coating exhibited an excellent mechanical properties which application for tools and molds.

Textures Applied to Mechanical Processing Technology Assessment in Ancient Bronze

2005 ◽  
Vol 495-497 ◽  
pp. 719-724
Author(s):  
R.E. Bolmaro ◽  
B. Molinas ◽  
E. Sentimenti ◽  
A.L. Fourty
Keyword(s):  
Orientation Distribution ◽  
Distribution Functions ◽  
Archaeological Sites ◽  
Mechanical Processing ◽  
Post Processing ◽  
X Ray Diffraction ◽  
Mechanical Process ◽  
X Ray ◽  
Pole Figures ◽  
Microscopic Inspection

Some ancient metallic art craft, utensils, silverware and weapons are externally undistinguishable from modern ones. Not only the general aspect and shape but also some uses have not changed through the ages. Moreover, when just some small pieces can be recovered from archaeological sites, the samples can not easily be ascribed to any known use and consequently identified. It is clear that mechanical processing has changed along history but frequently only a "microscopic" inspection can distinguish among different techniques. Some bronze samples have been collected from the Quarto d’Altino (Veneto) archaeological area in Italy (paleovenetian culture) and some model samples have been prepared by a modern artisan. The sample textures have been measured by X-ray Diffraction techniques. (111), (200) and (220) pole figures were used to calculate Orientation Distribution Functions and further recalculate pole figures and inverse pole figures. The results were compared with modern forging technology results. Textures are able to discern between hammering ancient techniques for sheet production and modern industrial rolling procedures. However, as it is demonstrated in the present work, forgery becomes difficult to detect if the goldsmith, properly warned, proceeds to erase the texture history with some hammering post-processing. The results of this contribution can offer to the archaeologists the opportunity to take into consideration the texture techniques in order to discuss the origin (culture) of the pieces and the characteristic mechanical process developed by the ancient artisan. Texture can also help the experts when discussing the originality of a certain piece keeping however in mind the cautions indicated in this publication.

Texture Development in a Model Al-Li Alloy Subjected to Severe Plastic Deformation

2006 ◽  
Vol 114 ◽  
pp. 337-344 ◽  
Author(s):  
Bogusława Adamczyk-Cieślak ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Extrusion ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
Technological Parameters ◽  
Initial State ◽  
Texture Characteristic ◽  
X Ray ◽  
Ultrafine Grained

The texture of Al – 0.7 wt. % Li alloy processed by two different methods of severe plastic deformation (SPD) has been investigated by X-ray diffraction, and analyzed in terms of the orientation distribution function (ODF). It was found that severe plastic deformation by both Equal Channel Angular extrusion (ECAE) and Hydrostatic Extrusion (HE) resulted in an ultrafine grained structure in an Al – 0.7 wt. % Li alloy. The microstructure, grain shape and size, of materials produced by SPD strongly depend on the technological parameters and methods applied. The texture of the investigated alloy differed because of the different modes of deformation. In the initial state the alloy exhibited a very strong texture consisting of {111} fibre component. A similar fibrous texture characteristic was also found after HE whereas after the ECAE the initial texture was completely changed.

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

scholarly journals Mechanochemical Synthesis of Fluorapatite-Zinc Oxide (FAp-ZnO) Composite Nanopowders

ISRN Ceramics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Bahman Nasiri-Tabrizi ◽  
Abbas Fahami
Keyword(s):  
Zinc Oxide ◽  
Average Crystallite Size ◽  
Structural Features ◽  
Morphological Features ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Remarkable Change ◽  
X Ray ◽  
Process Characterization ◽  
Ft Ir

Fluorapatite-zinc oxide (FAp-ZnO) composite nanopowders were successfully prepared via mechanochemical process. Characterization of the products was carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) analysis, energy dispersive X-ray spectroscopy (EDX), and field-emission scanning electron microscopy (FE-SEM) techniques. Results revealed that in the absence of ZnO which produced by hydrothermal method, the single-phase FAp had high-crystalline structure with appropriate morphological features. Furthermore, after 5 h of milling in the presence of 5 wt.% ZnO, FAp-5 wt.% ZnO, composite nanopowders with no impurity phase was obtained. Structural studies illustrated that the milling up to 5 h was not accompanied by a remarkable change in the structural features. Moreover, the gained composite powders presented an average crystallite size of about 40 nm for FAp. The FE-SEM observations indicated that the experimental outcome had a cluster-like structure which consisted of several small particles. Finally, results propose a new approach to prepare commercial amounts of novel FAp-based composite nanopowders with high quality and suitable structural and morphological features.

scholarly journals Structural characterization of the N-terminal part of the MERS-CoV nucleocapsid by X-ray diffraction and small-angle X-ray scattering

2016 ◽  
Vol 72 (2) ◽  
pp. 192-202 ◽  
Author(s):  
Nicolas Papageorgiou ◽  
Julie Lichière ◽  
Amal Baklouti ◽  
François Ferron ◽  
Marion Sévajol ◽  
...  
Keyword(s):  
Structural Model ◽  
Structural Features ◽  
Terminal Region ◽  
X Ray Diffraction ◽  
Terminal Part ◽  
Multifunctional Protein ◽  
X Ray ◽  
N Protein ◽  
Intrinsically Disordered ◽  
X Ray Scattering

The N protein of coronaviruses is a multifunctional protein that is organized into several domains. The N-terminal part is composed of an intrinsically disordered region (IDR) followed by a structured domain called the N-terminal domain (NTD). In this study, the structure determination of the N-terminal region of the MERS-CoV N proteinviaX-ray diffraction measurements is reported at a resolution of 2.4 Å. Since the first 30 amino acids were not resolved by X-ray diffraction, the structural study was completed by a SAXS experiment to propose a structural model including the IDR. This model presents the N-terminal region of the MERS-CoV as a monomer that displays structural features in common with other coronavirus NTDs.

Core-Shell SiO2/Ag Composite Spheres Prepared by Electrical Exploding Wire Plasma Technique: Synthesis and Characterization

2021 ◽  
Vol 19 (10) ◽  
pp. 82-88
Author(s):  
Duaa A. Uamran ◽  
Qasim Hassan Ubaid ◽  
Hammad R. Humud
Keyword(s):  
Laser Pulse ◽  
Laser Pulses ◽  
Structural Features ◽  
Optical Absorption Spectroscopy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Photocatalytic Activities ◽  
Core Shell Nanoparticles

Core-shell nanoparticles (SiO2/Ag) were manufactured by using a two-step process: Electric detonation of Ag. Wire in colloidal solution particles then by using laser pulses, nanoparticles are released. The structural features of these nanoparticles were checked by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The (XRD) study showed the progressive coverage of SiO2/Ag by nanoparticles according to the energies of the laser pulse. Measurements of morphology and EDX confirmed the Core/shell structure with particle size at the nano level. It confirmed that preliminary analysis consists of a SiO2 core and an Ag shell from FESEM. The surface of the microscopic balls (SiO2) has been covered completely and homogeneously with Ag nanoparticles, Moreover, Ultraviolet-Visible, and by optical absorption spectroscopy, the Nanoparticles with core crust SiO2/Ag showed excellent photocatalytic activities at various concentrations and laser pulse energy.

New Intermetallic Compounds RE4Co2Mg3 (RE = Pr, Gd, Tb, Dy) – Syntheses, Structure, and Chemical Bonding

2007 ◽  
Vol 62 (2) ◽  
pp. 162-168 ◽  
Author(s):  
Selcan Tuncel ◽  
Ute Ch. Rodewald ◽  
Samir F. Matar ◽  
Bernard Chevalier ◽  
Rainer Pöttgena
Keyword(s):  
Single Crystal ◽  
Intermetallic Compounds ◽  
Chemical Bonding ◽  
Structural Features ◽  
Induction Melting ◽  
Geometrical Constraint ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bonding Analysis ◽  
Magnesium Compounds

The magnesium compounds RE4Co2Mg3 (RE = Pr, Gd, Tb, Dy) were prepared by induction melting of the elements in sealed tantalum tubes. The samples were studied by powder X-ray diffraction. The structures of the gadolinium and of the terbium compound were refined from single crystal diffractometer data: Nd4Co2Mg3-type, P2/m, Z = 1, a = 754.0(4), b = 374.1(1), c = 822.5(3) pm, β = 109.65(4)°, wR2 = 0.0649, 730 F2 values for Gd4Co2Mg3 and a = 750.4(2), b = 372.86(6), c = 819.5(2) pm, β = 109.48(3)°, wR2 = 0.0398, 888 F2 values for Tb4Co2Mg3 with 30 variables each. The RE4Co2Mg3 structures are 3 : 1 intergrowth variants of distorted CsCl and AlB2 related slabs of compositions REMg and RECo2. Characteristic structural features (exemplary for Tb4Co2Mg3) are relatively short Tb-Co (271 pm), Co-Co (232 pm) and Mg-Mg (314 pm) distances. The latter are a geometrical constraint of the distortion of the REMg and RECo2 slabs. Chemical bonding analysis (ELF and ECOV data) for Gd4Co2Mg3 reveals strong Gd-Co bonding followed by Mg-Co, while the Mg-Mg interactions can be considered as weak. The Co-Co contacts are only weakly bonding. The bonding and antibonding states are almost filled.

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