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.

High-energy high-dose microfocus X-ray computed tomography driven by high-average-current photo-injector

2021 ◽  
pp. 1-12
Author(s):  
Dongcai Hu ◽  
Zheng Zhou ◽  
Jianxin Wang ◽  
Dexin Xiao ◽  
Kui Zhou ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Focal Spot ◽  
Spot Size ◽  
High Energy ◽  
High Density ◽  
High Dose ◽  
Focal Spot Size ◽  
X Ray ◽  
Average Current ◽  
X Ray Computed

High-energy, high-dose, microfocus X-ray computed tomography (HHM CT) is one of the most effective methods for high-resolution X-ray radiography inspection of high-density samples with fine structures. Minimizing the effective focal spot size of the X-ray source can significantly improve the spatial resolution and the quality of the sample images, which is critical and important for the performance of HHM CT. The objective of this study is to present a 9 MeV HHM CT prototype based on a high-average-current photo-injector in which X-rays with about 70μm focal spot size are produced via using tightly focused electron beams with 65/66μm beam size to hit an optimized tungsten target. In digital radiography (DR) experiment using this HHM CT, clear imaging of a standard 0.1 mm lead DR resolution phantom reveals a resolution of 6 lp/mm (line pairs per mm), while a 5 lp/mm resolution is obtained in CT mode using another resolution phantom made of 10 mm ferrum. Moreover, comparing with the common CT systems, a better turbine blade prototype image was obtained with this HHM CT system, which also indicates the promising application potentials of HHM CT in non-destructive inspection or testing for high-density fine-structure samples.

The identity of Monomia argentata (Crustacea : Brachyura : Portunidae) resolved by X-ray, computed tomography scanning and molecular comparisons

2017 ◽  
Vol 31 (6) ◽  
pp. 797 ◽  
Author(s):  
Milan Koch ◽  
Seyit A. Kamanli ◽  
Oliver Crimmen ◽  
Chia-Wei Lin ◽  
Paul F. Clark ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Dna Sequences ◽  
Species Complex ◽  
British Museum ◽  
Scanning Electron Micrographs ◽  
X Ray ◽  
Computed Tomography Scanning ◽  
X Ray Computed ◽  
Associated Species ◽  
Tomography Scanning

In his catalogue of British Museum Crustacea, Adam White listed two swimming crabs from Borneo as a new species, Amphitrite argentata, but he did not provide a description and therefore the name was a nomen nudum. Later, Alphonse Milne-Edwards described the larger of these male specimens as Neptunus argentatus and credited the species to White. Now assigned to Monomia Gistel, 1848, M. argentata was recently considered to represent a species-complex; however, its nomenclature and taxonomy have been confused over a long period of time. Furthermore, the larger syntype examined by Alphonse Milne-Edwards is no longer extant. The present study compared the smaller extant M. argentata male of White, here designated as the lectotype, with the description by A. Milne-Edwards. This dried specimen was re-examined using X-ray and computed tomography scanning techniques in order to reveal the general morphology of the first male gonopod (G1). Fresh material was collected and identified with confidence as M. argentata. This species was redescribed to modern standards including illustrations, details of coloration and new scanning electron micrographs of the G1 were provided. The validity of this species was further endorsed by comparing DNA sequences with congeners from the South China Sea. To conclude, the type status, authority and associated species-complex of M. argentata are discussed.

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