Effect of X-ray CT resolution on the quality of permeability computation for granular soils: definition of a criterion based on morphological properties

Soil Research ◽  
2019 ◽  
Vol 57 (6) ◽  
pp. 589 ◽  
Author(s):  
Miriam Patricia Ortega Ramírez ◽  
Laurent Oxarango ◽  
Alfonso Gastelum Strozzi
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Reference Value ◽  
Image Resolution ◽  
Morphological Properties ◽  
Morphological Description ◽  
Granular Soils ◽  
X Ray

In this study, the quality of soil permeability estimation based on computational fluid dynamics is discussed. Two types of three-dimensional geometries were considered: an image of Fontainebleau sand obtained from X-ray computed micro-tomography and a virtual pack of spheres. Numerical methods such as finite difference or lattice Boltzmann can conveniently use the image voxels as computational mesh elements. In this framework, the image resolution is directly associated with quality of the numerical computation. A higher resolution should promote both a better morphological description and discretisation. However, increasing the resolution may prevent the studied volume from being representative. Here, each sample was scaled and analysed at five resolutions. The dependence of soil properties with respect to the image resolution is discussed. As resolution decreased, the permeability and specific surface values tended to diverge from the reference value. This deterioration could be attributed to the shift of the pore size distribution towards badly resolved pores in the voxelised geometry. As long as granular soils are investigated, the volume fraction of pores smaller than six voxels in diameter should not exceed 50% to ensure the validity of permeability computation. In addition, based on an analysis of flow distribution, the volume fraction of pores smaller than four voxels should not exceed 25% in order to limit the flow rate occurring in badly discretised pores under 10%. For the Fontainebleau sand and virtual pack of spheres, the maximum voxel size meeting this criterion corresponded to 1/14 and 1/20 of the mean grain size respectively.

scholarly journals Three-dimensional propagation in near-field tomographic X-ray phase retrieval

2016 ◽  
Vol 72 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Aike Ruhlandt ◽  
Tim Salditt
Keyword(s):  
Phase Retrieval ◽  
Near Field ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Current Phase ◽  
Computationally Efficient ◽  
X Ray ◽  
Reconstruction Quality ◽  
Consistency Constraints

This paper presents an extension of phase retrieval algorithms for near-field X-ray (propagation) imaging to three dimensions, enhancing the quality of the reconstruction by exploiting previously unused three-dimensional consistency constraints. The approach is based on a novel three-dimensional propagator and is derived for the case of optically weak objects. It can be easily implemented in current phase retrieval architectures, is computationally efficient and reduces the need for restrictive prior assumptions, resulting in superior reconstruction quality.

Three-Dimensional Characterization of the Microstructure of Bioglass/Polyethylene Composite by X-Ray Microtomography

2007 ◽  
Vol 330-332 ◽  
pp. 503-506
Author(s):  
Xiao Wei Fu ◽  
Jie Huang ◽  
E.S. Thian ◽  
Serena Best ◽  
William Bonfield
Keyword(s):  
Spatial Distribution ◽  
Volume Fraction ◽  
Three Dimensional ◽  
X Ray ◽  
Polyethylene Composite ◽  
Bioactive Properties ◽  
Recent Developments ◽  
3D Information

A Bioglass® reinforced polyethylene (Bioglass®/polyethylene) composite has been prepared, which combines the high bioactivity of Bioglass® and the toughness of polyethylene. The spatial distribution of Bioglass® particles within the composite is important for the performance of composites in-vivo. Recent developments in X-ray microtomography (XμT) have made it possible to visualize internal and microstructural details with different X-ray absorbencies, nondestructively, and to acquire 3D information at high spatial resolution. In this study, the volume fraction and 3D spatial distribution of Bioglass® particles has been acquired quantitatively by XμT. The information obtained provides a foundation for understanding the mechanical and bioactive properties of the Bioglass®/polyethylene composites.

A modified discrete tomography for improving the reconstruction of unknown multi-gray-level material in the `missing wedge' situation

2018 ◽  
Vol 25 (6) ◽  
pp. 1847-1859 ◽  
Author(s):  
Jianhong Liu ◽  
Zhiting Liang ◽  
Yong Guan ◽  
Wenbin Wei ◽  
Haobo Bai ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Iteration Process ◽  
Reconstruction Technique ◽  
Morphological Operations ◽  
Algebraic Reconstruction Technique ◽  
Discrete Tomography ◽  
Boundary Extraction ◽  
X Ray ◽  
Dimensional Reconstruction

Full angular rotational projections cannot always be acquired in tomographic reconstructions because of the limited space in the experimental setup, leading to the `missing wedge' situation. In this paper, a recovering `missing wedge' discrete algebraic reconstruction technique algorithm (rmwDART) has been proposed to solve the `missing wedge' problem and improve the quality of the three-dimensional reconstruction without prior knowledge of the material component's number or the material's values. By using oversegmentation, boundary extraction and mathematical morphological operations, `missing wedge' artifact areas can be located. Then, in the iteration process, by updating the located areas and regions, high-quality reconstructions can be obtained from the simulations, and the reconstructed images based on the rmwDART algorithm can be obtained from soft X-ray nano-computed tomography experiments. The results showed that there is the potential for discrete tomography.

Three-dimensional magnetophotonic crystals based on artificial opals: fabrication and properties

2004 ◽  
Vol 834 ◽  
Author(s):  
A. V. Baryshev ◽  
T. Kodama ◽  
K. Nishimura ◽  
H. Uchida ◽  
M. Inoue
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Visible Region ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Dramatic Decrease ◽  
X Ray ◽  
Magnetophotonic Crystals ◽  
Magnetophotonic Crystal ◽  
Structural And Magnetic Properties

ABSTRACTWe have fabricated three-dimensional magnetophotonic (3D MPCs) crystals based on artificial opals. Structural and magnetic properties of 3D MPCs were studied by field emission scanning electron microscopy, x-ray diffraction analysis, and vibrating sample magnetometer. It was shown that increase of volume fraction of magnetite in the opal lattice leads to a dramatic decrease of transmitted light intensity in the visible region. We also found considerable changes in the Faraday rotation inside the (111) photonic bandgap of an opal—magnetite magnetophotonic crystal.

scholarly journals Three-dimensional Construction of Micrometer Level in Rat Stomach by Synchrotron RadiationThree-dimensional Construction of Micrometer Level in Rat Stomach by Synchrotron Radiation

2020 ◽  
Author(s):  
Qiang Tao ◽  
Chen-Chen Gao ◽  
Xue-Hong Tong ◽  
Shizhen Yuan ◽  
Tian-tian Wang ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Image Resolution ◽  
Phase Contrast Imaging ◽  
Imaging Method ◽  
Rat Stomach ◽  
Contrast Imaging ◽  
X Ray ◽  
3 Dimensional

Abstract Objectives This article shows an imaging method of the stomach that does not use imaging agents. X-ray phase-contrast images of different stages of gastric development were taken using X-ray in-line phase-contrast imaging (XILPCI). The aim of the study was to demonstrate that XILPCI is a micron imaging method for gastric structures. Methods The stomachs of 4-, 6- and 12-week-old rats were removed and cleaned. XILPCI has 1000 times greater soft tissue contrast than that of X-ray traditional absorption radiography. The projection images of the rats’ stomachs were recorded by an XILPCI charge coupled device (CCD) at 9 μm image resolution. Results The X-ray in-line phase-contrast images of the different stages of rat gastric specimens clearly showed the gastric architectures and the details of the gastroduodenal region. 3-dimensional stomach anatomical structure images were reconstruction. Conclusion The reconstructed gastric 3D images can clearly display the internal structure of the stomach. XILPCI may be a useful method for medical research in the future. Keywords: Synchrotron radiation phase-contrast imaging, 3-dimensional gastric structure images

INVESTIGATION OF POLYMER COMPOSITE MATERIAL SAMPLES BY X-RAY COMPUTED TOMOGRAPHY AND PROCESSING OF TOMOGRAMS WITH THE IMAGE OF THE VOLUME FRACTION OF POROSITY

2021 ◽  
pp. 105-113
Author(s):  
A.A. Demidov ◽  
◽  
O.A. Krupnina ◽  
N.A. Mikhaylova ◽  
E.I. Kosarina ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Polymer Composite ◽  
Volume Fraction ◽  
Filter Material ◽  
Polymer Composite Material ◽  
Tomographic Images ◽  
X Ray ◽  
X Ray Computed ◽  
Porosity Volume Fraction

The question of the quality of samples made of polymer composite materials and its verification by x-ray computed tomography is considered. The capabilities of North Star Imaging X5000 tomograph were studied and the samples from PCM were examined for detection and evaluation of the porosity volume fraction. The factors influencing the accuracy of the estimation of the porosity volume fraction are investigated. Namely the size voxel, a filter material, quantity of projections. On the other hand, the size вокселя defines resolution of the digital image, the relation depends on a material of the applied filter a signal/noise, productivity of control worsens with growth of quantity of projections. The choice of optimum values of the listed parametres is necessary for satisfactory quality received tomographic images.

scholarly journals Worldwide Protein Data Bank validation information: usage and trends

2018 ◽  
Vol 74 (3) ◽  
pp. 237-244 ◽  
Author(s):  
Oliver S. Smart ◽  
Vladimír Horský ◽  
Swanand Gore ◽  
Radka Svobodová Vařeková ◽  
Veronika Bendová ◽  
...  
Keyword(s):  
Protein Data Bank ◽  
Three Dimensional ◽  
Data Bank ◽  
Resonance Spectroscopy ◽  
X Ray ◽  
Validation Metrics ◽  
Task Forces ◽  
X Ray Crystallography ◽  
Structure Properties

Realising the importance of assessing the quality of the biomolecular structures deposited in the Protein Data Bank (PDB), the Worldwide Protein Data Bank (wwPDB) partners established Validation Task Forces to obtain advice on the methods and standards to be used to validate structures determined by X-ray crystallography, nuclear magnetic resonance spectroscopy and three-dimensional electron cryo-microscopy. The resulting wwPDB validation pipeline is an integral part of the wwPDB OneDep deposition, biocuration and validation system. The wwPDB Validation Service webserver (https://validate.wwpdb.org) can be used to perform checks prior to deposition. Here, it is shown how validation metrics can be combined to produce an overall score that allows the ranking of macromolecular structures and domains in search results. The ValTrendsDBdatabase provides users with a convenient way to access and analyse validation information and other properties of X-ray crystal structures in the PDB, including investigating trends in and correlations between different structure properties and validation metrics.

scholarly journals Reconstruction of crystal shapes by X-ray nanodiffraction from three-dimensional superlattices

2014 ◽  
Vol 47 (6) ◽  
pp. 2030-2037 ◽  
Author(s):  
Mojmír Meduňa ◽  
Claudiu V. Falub ◽  
Fabio Isa ◽  
Daniel Chrastina ◽  
Thomas Kreiliger ◽  
...  
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Semiconductor Layer ◽  
Dimensional Structure ◽  
Solid State Lasers ◽  
X Ray ◽  
Nondestructive Imaging ◽  
Low Dimensional

Quantitative nondestructive imaging of structural properties of semiconductor layer stacks at the nanoscale is essential for tailoring the device characteristics of many low-dimensional quantum structures, such as ultrafast transistors, solid state lasers and detectors. Here it is shown that scanning nanodiffraction of synchrotron X-ray radiation can unravel the three-dimensional structure of epitaxial crystals containing a periodic superlattice underneath their faceted surface. By mapping reciprocal space in all three dimensions, the superlattice period is determined across the various crystal facets and the very high crystalline quality of the structures is demonstrated. It is shown that the presence of the superlattice allows the reconstruction of the crystal shape without the need of any structural model.

Effect of Reinforcements on the Ultraprecision Performance of SiC Reinforced Aluminium Matrix Composites

2010 ◽  
Vol 154-155 ◽  
pp. 1342-1347
Author(s):  
Da Zhen Wang ◽  
Pei Feng Feng ◽  
Ling You
Keyword(s):  
Cutting Forces ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Aluminium Matrix ◽  
Matrix Composites ◽  
Aluminium Matrix Composites ◽  
Average Value ◽  
Sic Whiskers ◽  
Machined Surfaces

The experiments on ultraprecision turning of SiC reinforced aluminium composites have been done by using polycrystalloid diamond (PCD) tool with the three-dimensional cutting forces measured with a Kistler dynamometer, the quality of the machined surfaces was examined under Atom Force Microscope (AFM) and Scanning Electron Microscope (SEM) and the roughness of the machined surfaces was measured with roughometer of Talysurf-6. The experimental results show that the quality of the machined surfaces of SiC reinforced aluminium composites is predominantly controlled by the deformation mechanisms of SiC reinforcements, and the quality of the machined surfaces is better when reinforcements deform in the form of direct cutoff than in the form of pullout. The higher the volume fraction of SiC reinforcements, the worse the quality of the machined surfaces and the greater the amplitude of vibration and the average value of the cutting forces. On the same condition of volume fraction and cutting, the quality of the machined surfaces of SiC whiskers reinforced aluminium matrix composites is better than that of SiC particles reinforced aluminium matrix composites.

scholarly journals Wavefront Modulation and Beam Shaping into Arbitrary Three-Dimensional Intensity Distributions

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 179
Author(s):  
Tatiana Latychevskaia
Keyword(s):  
Three Dimensional ◽  
Beam Shaping ◽  
Intensity Modulation ◽  
Particle Trapping ◽  
X Ray ◽  
3D Structures ◽  
Spherical Waves

In this study the methods of three-dimensional (3D) wavefront intensity modulation by employing contrast-inverted holography, previously introduced as Gabor inverted holography, are further investigated. The present study provides the recipes for creating 3D wavefront intensity modulations using phase-only and amplitude-only modulators and compares the results. The 3D wavefront modulation using spherical waves is also demonstrated, and the miniaturization of 3D intensity beams is discussed; it is shown that both the resolution and the size of the created 3D structures are ultimately given by the wavelength of the employed radiation. The manuscript also addresses the quality of the formed 3D intensity curves and determines the parameters that provide the best smooth appearance of the 3D curves. The presented methods of 3D intensity wavefront modulation can be realized for all kinds of waves: light, X-ray, electron, etc, provided the modulator can be manufactured for the corresponding wavelength. The methods of 3D intensity wavefront modulation can be applied in various techniques: lithography, micro-robotics, particle trapping, etc.

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