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Abstract: Background/Objectives: Trabecular bone exhibits brittle behaviour governed by microscale deformation and damage, yet quantifying crack progression is difficult because classical fracture-mechanics approaches do not apply to architecturally discontinuous porous tissue. This pilot study evaluates whether synchrotron X-ray computed tomography (XCT) combined with digital volume correlation (DVC) can provide a practical, geometry-normalised approach for quantifying crack-opening behaviour in human trabecular bone. Methods: Semicylindrical specimens from femoral heads of hip-fracture donors (n = 5) and non-fracture controls (n = 5) underwent stepwise three-point bending during XCT imaging. Full-field displacement maps were used to measure crack mouth opening displacement (CMOD), crack length (a), and their ratio CMOD/a, used here as a geometry-normalised comparative descriptor of brittle response rather than an intrinsic material property. Automated phase-congruency crack detection (PCCD) was compared with manual measurement. Results: XCT–DVC resolved three-dimensional displacement discontinuities during crack initiation and propagation in all specimens. Hip-fracture donors exhibited significantly lower critical crack-opening ratios (CMOD/a)* than Controls (median 0.31 vs. 0.47; p = 0.008) and reached instability at lower applied loads. Total crack extension (Δa*) was similar between groups. Automated crack tracking using phase-congruency-based segmentation showed excellent agreement with manual measurements (r2 = 0.98), supporting reliable extraction of crack geometry from DVC displacement fields. Conclusions: In this small pilot sample, XCT–DVC provided a feasible, geometry-normalised approach for comparing crack-opening behaviour where classical fracture-mechanics parameters cannot be applied. The close agreement between automated and manual crack measurements supports the reproducibility of the displacement-based measurement pipeline. The lower critical CMOD/a in hip-fracture specimens may indicate a more brittle comparative response. However, given the small sample, differing sex distribution, and lower bone volume fraction in the hip-fracture group, these findings are preliminary and require confirmation in larger cohorts. Establishing whether the observed difference reflects intrinsic tissue brittleness, architectural factors, or both is an important objective for future work in microstructure-matched cohorts.

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Abstract: Utilizing green and renewable materials derived from biological sources is crucial for reducing environmental pollution. Natural wood is a clean and sustainable material. Densification methods have been shown to greatly enhance the mechanical properties of wood. However, the inherent hydrophilic and hygroexpansion characteristics of wood significantly limit the application of densified wood in various engineering fields. This study aimed to investigate the water absorption behavior and dimensional stability of natural and densified pine through water absorption experiments. The results showed that densified pine exhibited a similar three-stage water absorption behavior to that of natural pine. The water absorption behavior of densified pine caused by diffusion of water molecules as bound water in the cell wall (stage I), conforming to the Fickian model. In the subsequent stage II, excess water in the cell wall diffused into the cell lumen as free water. The water absorption behavior then deviated from the Fickian model and followed the Langmuir model. The significant reduction in the equilibrium moisture content of densified pine, compared to natural pine, can be attributed to a decrease in hemicellulose as well as smaller cell interstices and lumens. Moreover, unlike natural pine, where hygroexpansion was only in stage Ⅰ, densified pine expanded further in stage Ⅱ due to partial recovery of the cell lumen. Nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), Scanning electron microscopy (SEM) and X-ray computed tomography and diffraction techniques were employed to elucidate the effect of densification on dimensional stability and water absorption behavior of pine.

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Abstract: The deposition of functional coatings on open-cell foam substrates using magnetron sputtering is gaining popularity, particularly for applications like Oxygen Evolution Reaction (OER)/Hydrogen Evolution Reaction (HER) catalysis, batteries, and supercapacitors. While most research focuses on performance, little attention has been paid to the coating growth mechanisms or properties within the foam, which could significantly impact device performance. This work investigates the properties and growth mechanisms of TiO₂ coatings inside porous foams, using experimental and modeling techniques. The structure, composition and thickness of the coating on the outermost surface of the foam are studied using Focused Ion Beam (FIB), Scanning Transmission Electron Microscopy (STEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Selected Area Electron Diffraction (SAED) and High-Resolution Transmission Electron Microscopy (HRTEM). The experimental results reveal the formation of a dense, (quasi- )stoichiometric and crystalline coating. Numerical simulations and experiments highlight the transport of plasma particles in the foam. Interestingly, Direct Simulation Monte Carlo (DSMC)/Particle-In-Cell Monte Carlo (PICMC) models, coupled with Mass-Energy Analyzer (MEA) experiments, demonstrate that the particle flux is reduced, but the particle energy distribution is not Accepted Manuscript affected while traveling inside the foam. Using kinetic Monte Carlo (kMC) thin film growth models provided by Virtual CoaterTM, the physical properties of the coating inside the foam have been modeled, and the drop in coating thickness as well as the impact of bias voltage on densification, resistivity, and optical absorption are confirmed. Synchrotron X-Ray Diffraction (SXRD) analyses of the foam demonstrate that the same crystalline phase is obtained along the foam thickness, but it can be tailored with bias voltages. The decrease in the recorded SXRD signal with increasing depth inside the foam also suggests a drop in coating thickness. The new insights on the properties of coatings inside open-cell foams presented in this study can be used to improve future foam-based devices.

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Abstract: Fibrous plaster (FP) ceilings, prevalent in late 19th- and early 20th-century UK theatres, are suspended using ‘wads’. Wads are hangers made of Plaster of Paris, reinforced with twisted woven jute fabric. Several recent collapses in historic fibrous plaster ceilings have been attributed to tensile failures in wads. To understand the failure mechanisms involved, tensile tests were performed on laboratory-produced wad-like samples at the I12 beamline of the UK Diamond Light Source. The tested samples were designed with a dog bone shape and mounted with clevis-grips at each end, to ensure controlled failures along the gauge length. The beamline offered the opportunity to conduct simultaneous synchrotron X-ray computed tomography (sCT) and diffraction measurements during loading, enabling the monitoring of internal crack formation and strain propagation at the microstructural scale. Simultaneously, acoustic emission (AE) and digital image correlation (DIC) measurements were conducted. Preliminary results from these datasets are discussed in this paper. The datasets will provide useful information to validate the ongoing development of algorithms which can categorise the internal failure mechanisms and damage state of wads using only AE signals.

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Abstract: The capacity of polygranular graphite to accommodate strain is important to its use within structural components. This study has used in situ neutron and synchrotron X-ray experiments to demonstrate that reorientation of crystal domains accompanies the accommodation of applied mechanical strain in unirradiated Gilsocarbon (GCMB/IM24) graphite. Orientation changes were observed using 3D X-ray Diffraction, and local changes in neutron scattering were also observed with energy-resolved Bragg-edge neutron imaging. In both cases, this behaviour at the crystal level was partially recovered when the load was removed. This study provides new evidence for crystal deformation mechanisms that contribute to polycrystalline graphite's elastic non-linearity and the development of permanent set, which may also explain the effects of fast neutron irradiation on graphite elastic behaviour.