I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28804]
Open Access
Abstract: Melt flow is critical to build quality during additive manufacturing (AM). When an external magnetic field is applied, it causes forces that alter the flow through the thermoelectric magnetohydrodynamic (TEMHD) effect, potentially altering the final microstructure. However, the extent of TEMHD forces and their underlying mechanisms, remain unclear. We trace the flow of tungsten particles using in situ high-speed synchrotron X-ray radiography and ex situ tomography to reveal the structure of TEMHD-induced flow during directed energy deposition AM (DED-AM). When no magnetic field is imposed, Marangoni convection dominates the flow, leading to a relatively even particle distribution. With a magnetic field parallel to the scan direction, TEMHD flow is induced, circulating in the cross-sectional plane, causing particle segregation to the bottom and side of the pool. Further, a downward magnetic field causes horizontal circulation, segregating particles to the other side. Our results demonstrate that TEMHD can disrupt melt pool flow during DED-AM.
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Jun 2023
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[16557]
Open Access
Abstract: Achilles tendon rupture is a common debilitating medical condition. The healing process is slow and can be affected by heterotopic ossification (HO), which occurs when pathologic bone-like tissue is deposited instead of the soft collagenous tendon tissue. Little is known about the temporal and spatial progression of HO during Achilles tendon healing. In this study we characterize HO deposition, microstructure, and location at different stages of healing in a rat model. We use phase contrast-enhanced synchrotron microtomography, a state-of-the-art technique that allows 3D imaging at high-resolution of soft biological tissues without invasive or time-consuming sample preparation. The results increase our understanding of HO deposition, from the early inflammatory phase of tendon healing, by showing that the deposition is initiated as early as one week after injury in the distal stump and mostly growing on preinjury HO deposits. Later, more deposits form first in the stumps and then all over the tendon callus, merging into large, calcified structures, which occupy up to 10% of the tendon volume. The HOs were characterized by a looser connective trabecular-like structure and a proteoglycan-rich matrix containing chondrocyte-like cells with lacunae. The study shows the potential of 3D imaging at high-resolution by phase-contrast tomography to better understand ossification in healing tendons.
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Jun 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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A.
Koko
,
S.
Singh
,
S.
Barhli
,
T.
Connolley
,
N. T.
Vo
,
T.
Wigger
,
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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Krios I-Titan Krios I at Diamond
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James M.
Parkhurst
,
Adam D.
Crawshaw
,
C. Alistair
Siebert
,
Maud
Dumoux
,
C. David
Owen
,
Pedro
Nunes
,
David
Waterman
,
Thomas
Glen
,
David I.
Stuart
,
James H.
Naismith
,
Gwyndaf
Evans
Open Access
Abstract: Three-dimensional electron diffraction (3DED) from nanocrystals of biological macromolecules requires the use of very small crystals. These are typically less than 300 nm-thick in the direction of the electron beam due to the strong interaction between electrons and matter. In recent years, focused-ion-beam (FIB) milling has been used in the preparation of thin samples for 3DED. These instruments typically use a gallium liquid metal ion source. Inductively coupled plasma (ICP) sources in principle offer faster milling rates. Little work has been done to quantify the damage these sources cause to delicate biological samples at cryogenic temperatures. Here, an analysis of the effect that milling with plasma FIB (pFIB) instrumentation has on lysozyme crystals is presented. This work evaluates both argon and xenon plasmas and compares them with crystals milled with a gallium source. A milling protocol was employed that utilizes an overtilt to produce wedge-shaped lamellae with a shallow thickness gradient which yielded very thin crystalline samples. 3DED data were then acquired and standard data-processing statistics were employed to assess the quality of the diffraction data. An upper bound to the depth of the pFIB-milling damage layer of between 42.5 and 50 nm is reported, corresponding to half the thickness of the thinnest lamellae that resulted in usable diffraction data. A lower bound of between 32.5 and 40 nm is also reported, based on a literature survey of the minimum amount of diffracting material required for 3DED.
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May 2023
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I13-1-Coherence
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Valerio
Bellucci
,
Marie-Christine
Zdora
,
Ladislav
Mikes
,
Šarlota
Birnšteinová
,
Peter
Oberta
,
Marco
Romagnoni
,
Andrea
Mazzolari
,
Pablo
Villanueva-Perez
,
Rajmund
Mokso
,
Christian
David
,
Mikako
Makita
,
Silvia
Cipiccia
,
Jozef
Ulicny
,
Alke
Meents
,
Adrian P.
Mancuso
,
Henry N.
Chapman
,
Patrik
Vagovic
Diamond Proposal Number(s):
[17739]
Open Access
Abstract: The characterisation of fast phenomena at the microscopic scale is required for the understanding of catastrophic responses of materials to loads and shocks, the processing of materials by optical or mechanical means, the processes involved in many key technologies such as additive manufacturing and microfluidics, and the mixing of fuels in combustion. Such processes are usually stochastic in nature and occur within the opaque interior volumes of materials or samples, with complex dynamics that evolve in all three dimensions at speeds exceeding many meters per second. There is therefore a need for the ability to record three-dimensional X-ray movies of irreversible processes with resolutions of micrometers and frame rates of microseconds. Here we demonstrate a method to achieve this by recording a stereo phase-contrast image pair in a single exposure. The two images are combined computationally to reconstruct a 3D model of the object. The method is extendable to more than two simultaneous views. When combined with megahertz pulse trains of X-ray free-electron lasers (XFELs) it will be possible to create movies able to resolve 3D trajectories with velocities of kilometers per second.
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May 2023
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[25756]
Open Access
Abstract: Caries is a chronic disease that causes the alteration of the structure of dental tissues by acid dissolution (in enamel, dentine and cementum) and proteolytic degradation (dentine and cementum) and generates an important cost of care. There is a need to visualise and characterise the acid dissolution process on enamel due to its hierarchical structure leading to complex structural modifications. The process starts at the enamel surface and progresses into depth, which necessitates the study of the internal enamel structure. Artificial demineralisation is usually employed to simulate the process experimentally. In the present study, the demineralisation of human enamel was studied using surface analysis carried out with atomic force microscopy as well as 3D internal analysis using synchrotron X-ray tomography during acid exposure with repeated scans to generate a time-lapse visualisation sequence. Two-dimensional analysis from projections and virtual slices and 3D analysis of the enamel mass provided details of tissue changes at the level of the rods and inter-rod substance. In addition to the visualisation of structural modifications, the rate of dissolution was determined, which demonstrated the feasibility and usefulness of these techniques. The temporal analysis of enamel demineralisation is not limited to dissolution and can be applied to other experimental conditions for the analysis of treated enamel or remineralisation.
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May 2023
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I13-2-Diamond Manchester Imaging
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Carles
Bosch
,
Joerg
Lindenau
,
Alexandra
Pacureanu
,
Christopher J.
Peddie
,
Marta
Majkut
,
Andrew C.
Douglas
,
Raffaella
Carzaniga
,
Alexander
Rack
,
Lucy
Collinson
,
Andreas T.
Schaefer
,
Heiko
Stegmann
Diamond Proposal Number(s):
[20274]
Open Access
Abstract: Correlative multimodal imaging is a useful approach to investigate complex structural relations in life sciences across multiple scales. For these experiments, sample preparation workflows that are compatible with multiple imaging techniques must be established. In one such implementation, a fluorescently labeled region of interest in a biological soft tissue sample can be imaged with light microscopy before staining the specimen with heavy metals, enabling follow-up higher resolution structural imaging at the targeted location, bringing context where it is required. Alternatively, or in addition to fluorescence imaging, other microscopy methods, such as synchrotron x-ray computed tomography with propagation-based phase contrast or serial blockface scanning electron microscopy, might also be applied. When combining imaging techniques across scales, it is common that a volumetric region of interest (ROI) needs to be carved from the total sample volume before high resolution imaging with a subsequent technique can be performed. In these situations, the overall success of the correlative workflow depends on the precise targeting of the ROI and the trimming of the sample down to a suitable dimension and geometry for downstream imaging. Here, we showcase the utility of a femtosecond laser (fs laser) device to prepare microscopic samples (1) of an optimized geometry for synchrotron x-ray tomography as well as (2) for volume electron microscopy applications and compatible with correlative multimodal imaging workflows that link both imaging modalities.
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Apr 2023
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B16-Test Beamline
DIAD-Dual Imaging and Diffraction Beamline
E01-JEM ARM 200CF
E02-JEM ARM 300CF
I08-Scanning X-ray Microscopy beamline (SXM)
I12-JEEP: Joint Engineering, Environmental and Processing
I13-1-Coherence
I13-2-Diamond Manchester Imaging
I14-Hard X-ray Nanoprobe
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Open Access
Abstract: Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical–chemical–structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.
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Apr 2023
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Krios I-Titan Krios I at Diamond
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Xinrui
Huang
,
Iratxe
Torre
,
Michele
Chiappi
,
Zhan
Yin
,
Anupama
Vydyanath
,
Shuangyi
Cao
,
Oliver
Raschdorf
,
Morgan
Beeby
,
Bonnie
Quigley
,
Pieter P.
De Tombe
,
Jun
Liu
,
Edward P.
Morris
,
Pradeep K.
Luther
Diamond Proposal Number(s):
[18092]
Open Access
Abstract: Myosin binding protein C (MyBP-C) is an accessory protein of the thick filament in vertebrate cardiac muscle arranged over 9 stripes of intervals of 430 Å in each half of the A-band in the region called the C-zone. Mutations in cardiac MyBP-C are a leading cause of hypertrophic cardiomyopathy the mechanism of which is unknown. It is a rod-shaped protein composed of 10 or 11 immunoglobulin- or fibronectin-like domains labelled C0 to C10 which binds to the thick filament via its C-terminal region. MyBP-C regulates contraction in a phosphorylation dependent fashion that may be through binding of its N-terminal domains with myosin or actin. Understanding the 3D organisation of MyBP-C in the sarcomere environment may provide new light on its function. We report here the fine structure of MyBP-C in relaxed rat cardiac muscle by cryo-electron tomography and subtomogram averaging of refrozen Tokuyasu cryosections. We find that on average MyBP-C connects via its distal end to actin across a disc perpendicular to the thick filament. The path of MyBP-C suggests that the central domains may interact with myosin heads. Surprisingly MyBP-C at Stripe 4 is different; it has weaker density than the other stripes which could result from a mainly axial or wavy path. Given that the same feature at Stripe 4 can also be found in several mammalian cardiac muscles and in some skeletal muscles, our finding may have broader implication and significance. In the D-zone, we show the first demonstration of myosin crowns arranged on a uniform 143 Å repeat.
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Apr 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28804]
Open Access
Abstract: Directed energy deposition (DED) is a promising additive manufacturing technique for repair; however, DED is prone to surface waviness (humping) in thin-walled sections, which increases residual stresses and crack susceptibility, and lowers fatigue performance. Currently, the crack formation mechanism in DED is not well understood due to a lack of operando monitoring methods with high spatiotemporal resolution. Here, we use inline coherent imaging (ICI) to optically monitor surface topology and detect cracking in situ, coupled with synchrotron X-ray imaging for observing sub-surface crack healing and growth. For the first time, ICI was aligned off-axis (24° relative to laser), enabling integration into a DED machine with no alterations to the laser delivery optics. We achieved accurate registration laterally (<10 µm) and in depth (<3 µm) between ICI measurements and the laser beam position using a single-element MEMS scanner and a custom calibration plate. ICI surface topology is verified with corresponding radiographs (correlation >0.93), directly tracking surface roughness and waviness. We intentionally seed humping into thin-wall builds of nickel super-alloy CM247LC, locally inducing cracking in surface valleys. Crack openings as small as 7 µm were observed in situ using ICI, including sub-surface signal. By quantifying both humping and cracking, we demonstrate that ICI is a viable tool for in situ crack detection.
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Apr 2023
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