scholarly journals A Mineral X-ray Linear Attenuation Coefficient Tool (MXLAC) to Assess Mineralogical Differentiation for X-ray Computed Tomography Scanning

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 441
Author(s):  
Lunga Bam ◽  
Jodie Miller ◽  
Megan Becker
Keyword(s):  
Computed Tomography ◽  
Attenuation Coefficient ◽  
Data Bank ◽  
Linear Attenuation Coefficient ◽  
Chemical Formula ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Computed Tomography Scanning ◽  
X Ray Computed ◽  
Tomography Scanning

X-ray computed tomography (XCT) is becoming one of the most important techniques in the geosciences. The technique relies on linear attenuation coefficient differences in order to reveal the internal structure of the rocks. In this work, we present a new excel macro tool, called MXLAC, which is a data bank with an excel interface that uses density, X-ray energy and the mineral chemical formula to allow users to calculate mineral linear attenuation coefficients that can then be used to determine discrimination between mineral pairs. Elements within a mineral and specified by the chemical formula, determine how the X-ray beam is attenuated. Analysis of a variety of scanned mineral pairs with similar densities and attenuation coefficients indicates that an attenuation coefficient difference of greater than or equal to 6% at 45.5 keV effective X-ray energy is required for effective discrimination between two minerals using XCT with single energy scanning. This means that mineral pairs, such as quartz and pyrophyllite cannot be discriminated using the current XCT instruments due to the fact that the attenuation coefficient difference is less than 1.9% at 45.5 keV effective X-ray energy. Garnets and a variety of other minerals were used as examples to illustrate the importance of knowing the actual chemical formula of the mineral to demonstrate whether they can be partially or fully discriminated from each other.

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.

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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