scholarly journals Using X-Ray CT Scanning to Study the Failure Mechanism of Concrete under Static and Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Guangyu Lei ◽  
Jichang Han ◽  
Faning Dang
Keyword(s):  
Computed Tomography ◽  
Failure Mechanism ◽  
Static Load ◽  
Ct Scanning ◽  
Ct Images ◽  
X Ray ◽  
Dynamic Loadings ◽  
Ultimate Failure ◽  
X Ray Computed ◽  
Straight Lines

X-ray images can be used to nondestructively monitor the initiation, extension, and combination of cracks in concrete. In this study, real-time X-ray computed tomography (CT) scanning of concrete specimens under static and dynamic loadings was done. The CT images showed the growth, propagation, and penetration of the cracks and showed the ultimate failure of the concrete samples. Analysis of the CT images and CT numbers showed that the failure followed the structure’s areas of weakness under the static load, but for dynamic loading, the cracks formed very rapidly along straight lines through the aggregate.

Automatic Knot Detection in Coarse-Resolution Cone-Beam Computed Tomography Images of Softwood Logs

2019 ◽  
Vol 69 (3) ◽  
pp. 185-187
Author(s):  
Magnus Fredriksson ◽  
Julie Cool ◽  
Stavros Avramidis
Keyword(s):  
Computed Tomography ◽  
Exploratory Study ◽  
Ct Scanning ◽  
Detection Algorithm ◽  
Cone Beam ◽  
X Ray ◽  
Coarse Resolution ◽  
Computed Tomography Images ◽  
X Ray Computed ◽  
Accurate Position

Abstract X-ray computed tomography (CT) scanning of sawmill logs is associated with costly and complex machines. An alternative scanning solution was developed, but its data have not been evaluated regarding detection of internal features. In this exploratory study, a knot detection algorithm was applied to images of four logs to evaluate its performance in terms of knot position and size. The results were a detection rate of 67 percent, accurate position, and inaccurate size. Although the sample size was small, it was concluded that automatic knot detection in coarse resolution CT images of softwoods is feasible, albeit for knots of sufficient size.

scholarly journals Analysis of Coal Swelling Deformation Caused by Carbon Dioxide Adsorption Based on X-Ray Computed Tomography

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Xiangrong Nie ◽  
Junbin Chen ◽  
Yi Cao ◽  
Diguang Gong ◽  
Hao Deng
Keyword(s):  
Computed Tomography ◽  
Carbon Dioxide ◽  
Ct Scanning ◽  
Geologic Sequestration ◽  
Carbon Dioxide Adsorption ◽  
X Ray ◽  
Coal Beds ◽  
Coal Swelling ◽  
X Ray Computed ◽  
As Adsorption

The geologic sequestration of carbon dioxide by coal beds leads to the swelling deformation of coal. In order to investigate the swelling deformation characteristics at the microscopic scale, X-ray computed tomography (CT) scanning technology was used. X-ray CT scanning technology detects the internal structure, deformation, and porosity of coal at different gas pressures. Results show that swelling deformation is nonuniform, which is caused by the heterogeneity of the coal structure. Through quantitative measurement of the distance between fractures and pseudocolor processing of CT images, we observed that fractures gradually close with the increase of adsorption pressure. As adsorption pressure increases, the porosity of coal decreases, and the density of coal increases.

Visualization of diffusion phenomena in porous media by means of X-ray computed tomography (CT) scanning

2015 ◽  
Vol 52 (10) ◽  
pp. 1448-1456 ◽  
Author(s):  
Akira Sato ◽  
Koichi Ikeda
Keyword(s):  
Computed Tomography ◽  
Porous Materials ◽  
Diffusion Coefficients ◽  
Image Data ◽  
Ct Scanning ◽  
One Dimensional ◽  
X Ray ◽  
Water Permeation ◽  
X Ray Computed ◽  
Stone Structures

The migration of water and contamination materials in rock structures is a significant issue in projects that utilize deep underground locations such as “carbon-dioxide capture and storage” (CCS) and disposal of high-level nuclear waste. These phenomena are also important in the area of preservation of stone structures of cultural heritage signficance, as such stone structures are usually located outside, exposed to wind and rain. The migration of contamination materials in the underground environment, especially in porous rock mass, is governed mainly by water permeation and diffusion. In this study, one-dimensional diffusion testing was conducted and the process in the porous materials was visualized by X-ray computed tomography (CT) scanning. Diffusion is the process caused by the concentrate or density gradient, and is a suitable phenomenon for X-ray CT analysis. In this paper, information related to diffusion is extracted from X-ray CT image data and the distribution of concentration is estimated. From the obtained density distribution, diffusion coefficients are evaluated. One-dimensional permeation tests were also conducted and intrinsic permeabilities of porous materials are evaluated, then the relation between diffusion coefficients and intrinsic permeability is discussed.

scholarly journals Evaluation of Microstructure and Transport Properties of Deteriorated Cementitious Materials from Their X-ray Computed Tomography (CT) Images

Materials ◽  
2016 ◽  
Vol 9 (5) ◽  
pp. 388 ◽  
Author(s):  
Michael Promentilla ◽  
Shermaine Cortez ◽  
Regina Papel ◽  
Bernadette Tablada ◽  
Takafumi Sugiyama
Keyword(s):  
Computed Tomography ◽  
Transport Properties ◽  
Cementitious Materials ◽  
Ct Images ◽  
X Ray ◽  
X Ray Computed

scholarly journals The anatomy of the palate in Early Triassic Chaohusaurus brevifemoralis (Reptilia: Ichthyosauriformes) based on digital reconstruction

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11727
Author(s):  
Ya-Lei Yin ◽  
Cheng Ji ◽  
Min Zhou
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Ct Scanning ◽  
Lower Triassic ◽  
Early Triassic ◽  
Single Row ◽  
X Ray ◽  
Digital Reconstruction ◽  
X Ray Computed ◽  
First Time

The palatal anatomy of ichthyosauriforms remains largely unknown. Here, the complete palate of the early-branching ichthyosauriform Chaohusaurus brevifemoralis is reconstructed and described for the first time with the assistance of high-resolution X-ray computed tomography (CT) scanning on the basis of the three-dimensionally preserved skull of its paratype (GMPKU-P-3086) from the Lower Triassic of South China. The reconstruction reveals new palatal features of C. brevifemoralis. The palatine contacts the jugal directly, which is observed in ichthyosauriforms for the first time. A single row of denticles is present on each side of the palate. The vomer exceeds the anterior and posterior margins of the internal naris. The pterygoid is posterior to the internal naris. The epipterygoid is present and the ectopterygoid is absent.

scholarly journals Finding fossils in Malapa breccia – medical CT scanning or micro-CT scanning?

2017 ◽  
Vol 113 (11/12) ◽  
Author(s):  
Jacqueline S. Smilg
Keyword(s):  
Computed Tomography ◽  
Lower Energy ◽  
Ct Scanning ◽  
Cost Effective ◽  
High Energy ◽  
X Rays ◽  
Micro Ct ◽  
X Ray ◽  
Mechanical Preparation ◽  
X Ray Computed

Computed tomography (CT) imaging of fossils has revolutionised the field of palaeontology, allowing researchers to gain a better understanding of fossil anatomy, preservation and conservation. Micro focus X-ray computed tomography (μXCT) has been far more extensively used for these purposes than medical CT (XCT) – mostly because of the exquisite detail that the μXCT scanning modality, using slices of micron thicknesses, can produce. High energy X-rays can potentially penetrate breccia more effectively than lower energy beams. This study demonstrates that lower energy beams produce superior images for prioritising breccia for preparation. Additionally, XCT scanners are numerous, accessible, fast and relatively cost-effective when compared to μXCT scanners – the latter are not freely available, scanning times are much longer and there are significant limitations on the size and weight of scannable objects. Breccia blocks from Malapa were scanned at high and lower energy and images were analysed for image quality, artifact and certainty of diagnosis. Results show that lower energy images are deemed superior to higher energy images for this particular application. This finding, taken together with the limitations associated with the use of μXCT for the imaging of the large breccia from Malapa, shows that XCT is the better modality for this specific application. The ability to choose fossil-bearing breccia, ahead of manual mechanical preparation by laboratory technicians, would allow for the optimal use of limited resources, manual preparatory skills as well as the curtailment of costs.

scholarly journals A Design and Fabrication Method for Wood-Inspired Composites by Micro X-Ray Computed Tomography and 3D Printing

2020 ◽  
Vol 10 (4) ◽  
pp. 1400
Author(s):  
Yubo Tao ◽  
Zelong Li ◽  
Peng Li
Keyword(s):  
Computed Tomography ◽  
3D Printing ◽  
Region Of Interest ◽  
Ct Scanning ◽  
Quality Factors ◽  
Elementary Model ◽  
Wood Structures ◽  
X Ray ◽  
X Ray Computed ◽  
3D Volume

Developments in 3D printing and CT scanning technologies have facilitated the imitation of natural wood structures. However, creating composites from the elementary features of anisotropic wood structures remains a new frontier. This paper aims to investigate the potential of constructing and 3D printing mechanically customizable composites by combining anisotropic elementary models reconstructed from the micro X-ray computed tomography (μ-CT) scanning of wood. In this study, an arbitrary region of interest selected from the μ-CT scanning of a sample of Manchurian walnut (Juglans mandshurica) was reconstructed into isosurfaces that constituted the 3D model of an elementary model. Elementary models were combined to form the wood-inspired composites in various arrangements. The surface and interior structures of the elementary model were found to be customizable through adjusting the image Threshold and Surface Quality Factors during 3D volume reconstruction. Compressional simulations and experiments performed on the elementary model (digital and 3D printed) revealed that its compressive behavior was wood-like and anisotropic. Numerical analysis established a preliminary link between the arrangements of elementary models and the compressive stiffness of respective composites, showing that it is possible to control the compressive behaviors of the composites through the design of specific elementary model arrangements.

Effect of X-Ray Computed Tomography Scanning Parameters on the Estimated Porosity of Foam Specimens

2011 ◽  
Vol 110-116 ◽  
pp. 808-815 ◽  
Author(s):  
Jagadeesha Kumar ◽  
Abdul Hadi G. Abulrub ◽  
Alex Attridge ◽  
Mark A. Williams
Keyword(s):  
Computed Tomography ◽  
Focal Spot ◽  
Ct Scanning ◽  
Spot Size ◽  
Voxel Size ◽  
X Ray ◽  
Computed Tomography Scanning ◽  
X Ray Computed ◽  
Tomography Scanning ◽  
Segmentation Threshold

X-Ray Computed Tomography (CT) scanning is an effective method for estimating the porosity of various engineering materials and biomedical specimens such as tissue scaffolds and bones. However, the scanning and analysis parameters play a significant role in the accuracy of the porosity value determined from CT scan. This paper presents details of an investigation carried out to understand the effect of system parameters, namely the voxel size, X-ray focal spot size and segmentation threshold, on the estimated porosity by taking an example of safety-critical foam used for impact protection applications. Different voxel resolutions and focal spot sizes are selected in a total of 12 scanning tests and the effect of segmentation threshold is analyzed on each of these tests. The study indicates that the obtained porosity value is greatly influenced by the choice of voxel size at larger spot sizes and less influenced at smaller spot sizes. The threshold also has significant effect on the porosity value, especially at larger voxel sizes.

FOSSIL SECRETS REVEALED: X-RAY CT SCANNING AND APPLICATIONS IN PALEONTOLOGY

2016 ◽  
Vol 22 ◽  
pp. 21-38 ◽  
Author(s):  
Rachel Racicot
Keyword(s):  
Computed Tomography ◽  
General Public ◽  
Ct Scanning ◽  
Morphological Data ◽  
X Ray ◽  
Evolution And Development ◽  
X Ray Computed ◽  
Processing And Storage ◽  
And Storage ◽  
Digital Record

AbstractX-ray computed tomography (CT) provides a nondestructive means of studying the inside and outside of objects. It allows accurate visualization and measurement of internal features, that are otherwise impossible to obtain nondestructively, and is a lasting digital record that can be made available to future researchers, museums, and the general public. Here, an overview of CT scanning methodologies and protocol is provided, as well as some recent examples of how this technology is allowing paleontologists to make new inroads into understanding the ecology, evolution, and development of both extant and extinct organisms. Lastly, some frontiers and outstanding questions in the acquisition, processing, and storage of digital 3-D morphological data are highlighted.

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