I12-JEEP: Joint Engineering, Environmental and Processing
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A.
Koko
,
S.
Singh
,
S.
Barhli
,
T.
Connolley
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N. T.
Vo
,
T.
Wigger
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D.
Liu
,
Y.
Fu
,
J.
Réthoré
,
J.
Lechambre
,
J.-Y.
Buffiere
,
T. J.
Marrow
Diamond Proposal Number(s):
[12585]
Open Access
Abstract: The propagation rate of a fatigue crack in a nodular cast iron, loaded in cyclic tension, has been studied in situ by X-ray computed tomography and digital volume correlation. The semi-elliptical crack initiated from an asymmetric corner notch and evolved to a semi-circular shape, initially with a higher growth rate towards one edge of the notch before the propagation rate along the crack front became essentially independent of po-sition. The phase congruency of the displacement field was used to measure the crack shape. The three-dimensional stress intensity factors were calculated via a linear elastic finite element model that used the displacement fields around the crack front as the boundary conditions. Closure of the crack tip region was observed. The cyclic change in the local mode I opening of the crack tip determined the local fatigue crack propaga-tion rate along the crack front.
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May 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[29710]
Open Access
Abstract: The origin of jaws and teeth remains contentious in vertebrate evolution. ‘Placoderms’ (Silurian-Devonian armoured jawed fishes) are central to debates on the origins of these anatomical structures. ‘Acanthothoracids’ are generally considered the most primitive ‘placoderms’. However, they are so far known mainly from disarticulated skeletal elements that are typically incomplete. The structure of the jaws—particularly the jaw hinge—is poorly known, leaving open questions about their jaw function and comparison with other placoderms and modern gnathostomes. Here we describe a near-complete ‘acanthothoracid’ upper jaw, allowing us to reconstruct the likely orientation and angle of the bite and compare its morphology with that of other known ‘placoderm’ groups. We clarify that the bite position is located on the upper jaw cartilage rather than on the dermal cheek and thus show that there is a highly conserved bite morphology among most groups of ‘placoderms’, regardless of their overall cranial geometry. Incorporation of the dermal skeleton appears to provide a sound biomechanical basis for jaw origins. It appears that ‘acanthothoracid’ dentitions were fundamentally similar in location to that of arthrodire ‘placoderms’, rather than resembling bony fishes. Irrespective of current phylogenetic uncertainty, the new data here resolve the likely general condition for ‘placoderms’ as a whole, and as such, ancestral morphology of known jawed vertebrates.
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Feb 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Open Access
Abstract: Deformation bands, or tabular zones of localised strain, are a common manifestation of deformation in upper crustal sedimentary rocks. Any mining or energy-related engineering applications must consider the possibility of reactivating these pre-existing failure planes because doing so can cause seismicity and compartmentalise the reservoir. However, there has only been a small amount of research done on laboratory-induced deformation in rocks with natural deformation features.
On a low porosity bioclastic calcarenite from the Cotiella Basin, Spanish Pyrenees, our current experimental work aims to capture, for the first time to our knowledge, the dominant failure mechanisms during the reactivation of natural deformation bands oriented at different angles to the principal stress direction. At the I12-JEEP beamline at the synchrotron facility of Diamond Light Source, UK, we carried out triaxial compression experiments using a modified version of the Mjolnir cell used by Cartwright-Taylor et al., (2022) to examine how these highly heterogeneous rocks respond to additional mechanical deformation. During the deformation experiments, 4D (time and space) x-ray tomography images (8 m voxel size resolution) were acquired. We tested confining pressures between 10 MPa and 30 MPa.
The mechanical data demonstrate that the existence of natural deformation features within the tested samples weakens the material. For instance, solid samples of the host rock subjected to the same confining pressures had higher peak differential stresses. Additionally, our findings demonstrate that new deformation bands form as their angle, θ, to σ1 increases, while the reactivation of pre-exiting deformation bands in this low porosity carbonate only occurs for dipping angles close to 70o. The spatio-temporal relationships between the naturally occurring and laboratory-induced deformation bands and fractures were investigated using time-resolved x-ray tomography and Digital Volume Correlation (DVC). Volumetric and shear strain fields were calculated using the SPAM software (Stamati et al., 2020). The orientation of the recently formed failure planes is influenced by the orientation of the pre-existing bands, as well as their width and the presence (or absence) of porosity along their length. Additionally, pre-existing secondary deformation features found in the tested material trigger additional mechanical damage that either promotes the development or deflects the new failure planes.
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Feb 2023
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I13-2-Diamond Manchester Imaging
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Abstract: Accurately estimating developmental age and life history traits in fossils is crucial for identifying
and classifying extinct species and understanding how biological attributes evolved. The
evolution of life history traits such as growth pattern is far from clear in birds, and development
has been studied in only a handful of modern species. The exceptionally rapid growth of
modern birds means ageing methods based on annual incremental growth lines, used in other
vertebrates, are inapplicable to birds and robust alternative methods remain to be established.
Analysis of avian intracortical bone microstructure, which varies both with age and tissue
deposition rate, is a promising approach already used in palaeobiology. However, current thin
section-based histological methods are destructive. Moreover, to date, most microstructural
studies in avian bone are qualitative, 2D, and involve a limited range of extant species. The
objective of this study was to investigate cortical bone microstructure and developmental age
and life history traits in living birds, to identify phenotypes which can then be applied to
examination of the fossil record, using minimally-destructive high-resolution 3D imaging.
First, the necessity of 3D measurement was tested: a combination of idealised, simulated
datasets and real synchrotron-based computed tomography (SR CT) datasets were used to
compare published methods for measuring key microstructural traits based on 2D sections and
3D volumes. Next, SR CT imaging and quantitative measurements were used to characterise
age-related changes in bone microstructure in a range of extant bird species: growth series
ducks and pheasants, and a smaller sample size in starlings, rock doves, partridges, and ostrich.
The methods tested in modern material were applied to fossils as a proof-of concept.
It was found that 3D quantification methods are required for measuring vascular canal
orientation and osteocyte lacunar shape and volume, though 2D sections could be used to
measure traits such as bone volume fraction (BV/TV) and osteocyte lacunar volume. In all
species studied, juvenile, subadult, and adult species could be distinguished by their values of
BV/TV, and further information could be added using measured values of vascular canal
diameter as well as qualitative assessment. Using a synchrotron-based CT system,
high-resolution 3D datasets comparable to modern bone samples were obtained from fossils,
and preliminary estimates of developmental age can be made.
Further work may reveal more changes within juvenile age stages, and better characterise the
variation within extant birds, allowing more accurate interpretation of the fossil record.
Therefore developmental studies in a greater number of extant bird species are required using
larger sample sizes, to support and add to the results presented in this thesis.
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Jan 2023
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[16205]
Open Access
Abstract: Methane (CH4) hydrate dissociation and CH4 release are potential geohazards currently investigated using X-ray computed tomography (XCT). Image segmentation is an important data processing step for this type of research. However, it is often time consuming, computing resource-intensive, operator-dependent, and tailored for each XCT dataset due to differences in greyscale contrast. In this paper, an investigation is carried out using U-Nets, a class of Convolutional Neural Network, to segment synchrotron XCT images of CH4-bearing sand during hydrate formation, and extract porosity and CH4 gas saturation. Three U-Net deployments previously untried for this task are assessed: (1) a bespoke 3D hierarchical method, (2) a 2D multi-label, multi-axis method and (3) RootPainter, a 2D U-Net application with interactive corrections. U-Nets are trained using small, targeted hand-annotated datasets to reduce operator time. It was found that the segmentation accuracy of all three methods surpass mainstream watershed and thresholding techniques. Accuracy slightly reduces in low-contrast data, which affects volume fraction measurements, but errors are small compared with gravimetric methods. Moreover, U-Net models trained on low-contrast images can be used to segment higher-contrast datasets, without further training. This demonstrates model portability, which can expedite the segmentation of large datasets over short timespans.
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Dec 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28603]
Open Access
Abstract: Small-diameter, thin-walled pipes have applications in a wide range of industries including high-energy physics, heat transfer, nuclear, medical and communications. There are no standards that exist for welds less than 0.5 mm in width, and as such it is difficult to determine the likely performance of a thin-walled pipe weld. Porosity is largely inevitable in fusion welded joints and is a determining factor in the performance of a connection.
This study focused on characterisation of the evolution of strains in soldered welds less than 0.5 mm in width, by incrementally tensile loading samples and studying them in-situ with Synchrotron X-Ray Computed Tomography and X-Ray Diffraction. Two sample geometries were studied, and porosity defects were present in both, although the levels of porosity size, number and area varied dramatically between the two samples.
Lattice strain interpretation showed that crack propagation for such samples is not driven by porosity but that crack evolution occurs at the same location and load levels irrespective of the presence of pores. Residual stresses of up to 0.3% from the fusion welding process were seen in both samples and appear to have a greater impact on locations of failure than porosity. Porosity does cause differences in strains across directions, however high strains alone did not appear to cause premature failure. Hence, efforts to improve weld strength should in future focus more on reducing residual stresses than reducing porosity.
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Dec 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Chu Lun Alex
Leung
,
Matthew D.
Wilson
,
Thomas
Connolley
,
Stephen P.
Collins
,
Oxana V.
Magdysyuk
,
Matthieu N.
Boone
,
Kosuke
Suzuki
,
Matthew C.
Veale
,
Enzo
Liotti
,
Frederic
Van Assche
,
Andrew
Lui
,
Chun
Huang
Diamond Proposal Number(s):
[23400]
Open Access
Abstract: Increasing electrode thickness is gaining more attention as a potential route to increase energy density for Li ion batteries although the realizable capacity and rate capability are usually limited by Li+ ion diffusion during (dis)charge, especially at increased (dis)charge rates. It remains challenging to visualize and quantify the low atomic number Li+ chemical stoichiometry distribution inside the electrode within commercially standard battery geometry, e.g., coin cells with stainless steel casings. Here, we map the distribution of Li+ chemical stoichiometry in the electrode microstructure inside a working coin cell battery to show the amount of electrode materials contributing to energy storage performance using innovative in situ correlative full-field X-ray Compton scattering imaging (XCS-I) and X-ray computed tomography (XCT). We design and fabricate an ultra-thick (∼1 mm) cathode of LiNi0.8Mn0.1Co0.1O2 with a microstructure containing vertically oriented pore arrays using a directional ice templating method. This novel technique paves a new way to map low atomic number elements in 3D structures and study how the microstructure improves Li+ ion diffusivity and energy storage performance.
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Dec 2022
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[28574]
Open Access
Abstract: We present a flyscan compatible acquisition scheme for three-modal X-Ray Computed Tomography (CT) with two-dimensional phase sensitivity. Our approach is demonstrated using a “beam tracking” setup, through which a sample’s attenuation, phase (refraction) and scattering properties can be measured from a single frame, providing three complementary contrast channels. Up to now, such setups required the sample to be stepped at each rotation angle to sample signals at an adequate rate, to prevent resolution losses, anisotropic resolution, and under-sampling artefacts. However, the need for stepping necessitated a step-and-shoot implementation, which is affected by motors’ overheads and increases the total scan time. By contrast, our proposed scheme, by which continuous horizontal and vertical translations of the sample are integrated with its rotation (leading to a “cycloidal-spiral” trajectory), is fully compatible with continuous scanning (flyscans). This leads to greatly reduced scan times while largely preserving image quality and isotropic resolution.
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Dec 2022
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I13-2-Diamond Manchester Imaging
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Francesca
Palermo
,
Nicola
Pieroni
,
Alessia
Sanna
,
Benedetta
Parodi
,
Consuelo
Venturi
,
Ginevra
Begani Provinciali
,
Lorenzo
Massimi
,
Laura
Maugeri
,
Gian Paolo
Marra
,
Elena
Longo
,
Lorenzo
D’amico
,
Giulia
Saccomano
,
Jonathan
Perrin
,
Giuliana
Tromba
,
Inna
Bukreeva
,
Michela
Fratini
,
Giuseppe
Gigli
,
Nicole
Kerlero De Rosbo
,
Alessia
Cedola
Diamond Proposal Number(s):
[23997]
Open Access
Abstract: The 3D complexity of biological tissues and intricate structural-functional connections call for state-of-the-art X-ray imaging approaches to overcome limitations of classical imaging. Unlike other imaging techniques, X-ray phase-contrast tomography (XPCT) offers a highly sensitive 3D imaging approach to investigate different disease-relevant networks at levels ranging from single cell through to intact organ. We present here a concomitant study of the evolution of tissue damage and inflammation in different organs affected by the disease in the murine model for multiple sclerosis, a demyelinating autoimmune disorder of the central nervous system. XPCT identifies and monitors structural and cellular alterations throughout the central nervous system, but also in the gut, and eye, of mice induced to develop multiple sclerosis-like disease and sacrificed at pre-symptomatic and symptomatic time points. This study details the sequential evolution of multi-organ damages in the murine multiple sclerosis model showing the disease development and progression which is of relevance for the human case.
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Nov 2022
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[16557]
Open Access
Abstract: Skeletal muscle contractions are critical for normal skeletal growth and morphogenesis but it is unclear how the detrimental effects of absent muscle on the bones and joints change over time. Joint shape and cavitation as well as rudiment length and mineralisation were assessed in multiple rudiments at two developmental stages [Theiler stage (TS)24 and TS27] in the splotch-delayed “muscle-less limb” mouse model and littermate controls. Chondrocyte morphology was quantified in 3D in the distal humerus at the same stages. As development progressed, the effects of absent muscle on all parameters except for cavitation become less severe. All major joints in muscle-less limbs were abnormally shaped at TS24, while, by TS27, most muscle-less limb joint shapes were normal or nearly normal. In contrast, any joints that were fused at TS24 did not cavitate by TS27. At TS24, chondrocytes in the distal humerus were significantly smaller in the muscle-less limbs than in controls, while by TS27, chondrocyte volume was similar between the two groups, offering a cell-level mechanism for the partial recovery in shape of muscle-less limbs. Mineralisation showed the most pronounced changes over gestation. At TS24, all muscle-less rudiments studied had less mineralisation than the controls, while at TS27, muscle-less limb rudiments had mineralisation extents equivalent to controls. In conclusion, the effects of muscle absence on prenatal murine skeletogenesis reduced in severity over gestation. Understanding how mammalian bones and joints continue to develop in an environment with abnormal fetal movements provides insights into conditions including hip dysplasia and arthrogryposis.
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Nov 2022
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