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In the case of the point defect in a crystal, the inverse Radon’s problem in X-ray diffraction microtomography has been solved. As is known, the crystal-lattice defect displacement field function f(r) = h·u(r) determines phases − (±h)-structure factors incorporated into the Takagi–Taupin equations and provides the 2D image patterns by diffracted and transmitted waves propagating through a crystal (h is the diffraction vector and u(r) is the displacement field crystal-lattice-defects vector). Beyond the semi-kinematical approach for obtaining the analytical problem solution, the difference-equations-scheme of the Takagi–Taupin equations that, in turn, yield numerically controlled-accuracy problem solutions has been first applied and tested. Addressing the inverse Radon’s problem solution, the χ2-target function optimization method using the Nelder–Mead algorithm has been employed and tested in an example of recovering the Coulomb-type point defect structure in a crystal Si(111). As has been shown in the cases of the 2D noise-free fractional and integrated image patterns, based on the Takagi–Taupin solutions in the semi-kinematical and difference-scheme approaches, both procedures provide the χ2-target function global minimum, even if the starting-values of the point-defect vector P1 is chosen rather far away from the reference up to 40% in relative units. In the cases of the 2D Poisson-noise image patterns with noise levels up to 5%, the figures-of-merit values of the optimization procedures by the Nelder–Mead algorithm turn out to be high enough; the lucky trials number is 85%; and in contrast, for the statistically denoised 2D image patterns, they reach 0.1%.

A central point of validity of computer X-ray diffraction micro tomography is to improve the digital contrast and spatial resolution of the 3D-recovered nano-scaled objects in crystals. In this respect, the denoising issue of the 2D image patterns data involved in the 3D high-resolution recovery processing has been treated. The Poisson-noise simulation of 2D image patterns data was performed; afterwards, it was employed for recovering nano-scaled crystal structures. By using the statistical average and geometric means methods of the acquired 2D image frames, we showed that the statistical average hypothesis works well, at least in the case of 2D Poisson-noise image data related to the Coulomb-type point defect in a crystal Si(111). The validation of results related to the de-noised 2D IPs data obtained was carried out by both the 3D recovery processing of the Coulomb-type point defect in a crystal Si(111) and using the peak signal-to-noise ratio (PSNR) criterion.

Powder-based inkjet 3D printing method is one of the most attractive solid free form techniques. It involves a sequential layering process through which 3D porous scaffolds can be directly produced from computer-generated models. 3D printed products' quality are controlled by the optimal build parameters. In this study, Calcium Sulfate based powders were used for porous scaffolds fabrication. The printed scaffolds of 0.8 mm pore size, with different layer thickness and printing orientation, were subjected to the depowdering step. The effects of four layer thicknesses and printing orientations, (parallel to X, Y and Z), on the physical and mechanical properties of printed scaffolds were investigated. It was observed that the compressive strength, toughness and Young's modulus of samples with 0.1125 and 0.125 mm layer thickness were more than others. Furthermore, the results of SEM and μCT analyses showed that samples with 0.1125 mm layer thickness printed in X direction have more dimensional accuracy and significantly close to CAD software based designs with predefined pore size, porosity and pore interconnectivity.

Multi-technique characterisation of sodium carbonate-activated blast furnace slag binders was conducted in order to determine the influence of the carbonate groups on the structural and chemical evolution of these materials. At early age (<4 days) there is a preferential reaction of Ca 2+ with the CO 3 2− from the activator, forming calcium carbonates and gaylussite, while the aluminosilicate component of the slag reacts separately with the sodium from the activator to form zeolite NaA. These phases do not give the high degree of cohesion necessary for development of high early mechanical strength, and the reaction is relatively gradual due to the slow dissolution of the slag under the moderate pH conditions introduced by the Na 2 CO 3 as activator. Once the CO 3 2− is exhausted, the activation reaction proceeds in similar way to an NaOH-activated slag binder, forming the typical binder phases calcium aluminium silicate hydrate and hydrotalcite, along with Ca-heulandite as a further (Ca,Al)-rich product. This is consistent with the significant gain in compressive strength and reduced porosity observed after 3 days of curing. The high mechanical strength and reduced permeability developed in these materials beyond 4 days of curing elucidate that Na 2 CO 3 -activated slag can develop desirable properties for use as a building material, although the slow early strength development is likely to be an issue in some applications. These results suggest that the inclusion of additions which could control the preferential consumption of Ca 2+ by the CO 3 2− might accelerate the reaction kinetics of Na 2 CO 3 -activated slag at early times of curing, enhancing the use of these materials in engineering applications.

GeoSoilEnviroCARS (GSECARS) is a comprehensive analytical laboratory for Earth and environmental science research using X-ray beams from the Advanced Photon Source, Argonne National Laboratory. State-of-the-art instruments are available for (1) high-pressure/high- or low-temperature diffraction, total scattering, and spectroscopy (Brillouin, Raman, and VIS-IR) using the laser heated diamond anvil cell (DAC); (2) high-pressure/high-temperature diffraction, scattering, and imaging as well as acoustic emission (AE) and ultrasonics using the large-volume press (LVP); (3) powder, single crystal, and surface/interface diffraction; (4) X-ray absorption fine structure spectroscopy; (5) X-ray fluorescence microprobe analysis; and (6) microtomography. Experiments are facilitated by senior level staff who collaborate on all aspects of the analytical work including experiment design, sample preparation, data collection, data interpretation, and publication preparation. Both technical and scientific synergies occur as a result of the intimate association of the various techniques and scientists experienced in the applications of synchrotron radiation to Earth, environmental, and planetary science problems. The facility includes state-of-the-art instrumentation designed and built in-house, including custom X-ray optics, online and offline laser-based systems, specialized sample environments and positioning systems, as well as pixel-array and multi-crystal energy dispersive X-ray detectors, which are available to be shared among the experimental stations.

Turquoise is a well-known gemstone that has been used in artefacts across many cultures throughout history. However, due to its porosity it is often treated to enhance its color and beauty. One appreciated treatment is the patented Zachery process, although its details remain publicly undisclosed. Previous studies indicated that only a high K content distinguishes Zachery-treated from natural turquoises. In this study, natural and Zachery-treated turquoise samples from the famous Kingman mine, Arizona, USA, were analysed by means a multi-methodological approach, including standard gemological testing, electron microprobe (EMPA), scanning electron microscope with energy dispersive spectrometer (SEM–EDS) and X-ray diffraction (XRD), Fourier-Transform InfraRed (FTIR), non-destructive External Reflection-Fourier-Transform InfraRed (ER-FTIR) spectroscopy and X-ray computed microtomography (μCT). The results revealed new chemical–mineralogical and microstructural features that distinguish the Zackery-treated from the natural turquoise: higher specific gravity and lower porosity, associated with high and uneven concentrations of Cu, K and Na, the occurrence of tenorite (CuO), the presence and extension of reaction edges in the entire volume are distinctive of treated samples. Moreover, Cu-rich seeds and feldspar crystals may be interpreted as additional components used during the treatment. The hypothesis is that the Zachery treatment induces the re-crystallization of a new turquoise-like phase, which differs from the natural one from a chemical and microstructural point of view.

Understanding the mechanisms of kidney stone formation, development patterns and associated pathological features are gaining importance due to an increase in the prevalence of the disease and diversity in the presentation of the stone composition. Based on the microstructural characteristics of kidney stones, it may be possible to explain the differences in the pathogenesis of pure and mixed types of stones. In this study, the microstructure and distribution of mineral components of kidney stones of different mineralogy (pure and mixed types) were analyzed. The intact stones removed from patients were investigated using synchrotron radiation X-ray computed microtomography (SR-μCT) and the tomography slice images were reconstructed representing the density and structure distribution at various elevation planes. Infrared (IR) spectroscopes, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to confirm the bulk mineral composition in the thin section stones. Observations revealed differences in the micro-morphology of the kidney stones with similar composition in the internal 3-D structure. Calcium oxalate monohydrate stones showed well-organised layering patterns, while uric acid stones showed lower absorption signals with homogenous inner structure. Distinct mineral phases in the mixed types were identified based on the differential absorption rates. The 3-D quantitative analysis of internal porosity and spatial variation between nine different types of stones were compared. The diversity among the microstructure of similar and different types of stones shows that the stone formation is complex and may be governed by both physiological and micro-environmental factors. These factors may predispose a few towards crystal aggregation and stone growth, while, in others the crystals may not establish stable attachment and/or growth.

The link between the structural organization of the fibrillar components of lung extracellular matrix (ECM), local tissue stiffness and global viscoelastic behaviour is not known. Here we investigated the effect of injurious mechanical ventilation on the local lung tissue stiffness using 4D synchrotron phase-contrast micro-CT, in normal lung and 7 days after intratracheal bleomycin induced lung injury in anesthetized rats. Quantitative maps of local lung strain (ε) were computed within aerated lung acini, using a stepwise image registration method. Fibrillar organization of collagen and elastin at the nanoscale was measured using synchrotron small-angle x-ray scattering (SAXS). Local microscopic tissue ε was reduced in the aerated acini of normal lungs post injurious ventilation and in bleomycin-injured lungs and was associated with an increase in dynamic elastance (H). The scattering peak angle (q) which is inversely related to fibril D-spacing, was decreased by injurious ventilation indicating an elongation of the collagen fibril spacing in both normal and bleomycin-injured lung. There was a positive relationship between collagen periodicity and global tissue elastance, while an inverse relation was observed with tissue hysteresis. Our data demonstrate the effect of both bleomycin-induced lung injury and high-strain mechanical ventilation on the nanoscale fibrillar organization of collagen and for the first time, a link between collagen D-spacing and global lung tissue stiffening and viscoelastic behaviour.

The performance of dental resin-based composites (RBCs) heavily depends on the characteristic properties of the individual filler fraction. As specific information regarding the properties of the filler fraction is often missing, the current study aims to characterize the filler fractions of several contemporary computer-aided design/computer-aided manufacturing (CAD/CAM) RBCs from a material science point of view. The filler fractions of seven commercially available CAD/CAM RBCs featuring different translucency variants were analysed using Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Micro-X-ray Computed Tomography (µXCT), Thermogravimetric Analysis (TG) and X-ray Diffractometry (XRD). All CAD/CAM RBCs investigated included midifill hybrid type filler fractions, and the size of the individual particles was clearly larger than the individual specifications of the manufacturer. The fillers in Shofu Block HC featured a sphericity of ≈0.8, while it was <0.7 in all other RBCs. All RBCs featured only X-ray amorphous phases. However, in Lava Ultimate, zircon crystals with low crystallinity were detected. In some CAD/CAM RBCs, inhomogeneities (X-ray opaque fillers or pores) with a size <80 µm were identified, but the effects were minor in relation to the total volume (<0.01 vol.%). The characteristic parameters of the filler fraction in RBCs are essential for the interpretation of the individual material’s mechanical and optical properties.

Mild hypophosphatasia (HPP) can be difficult to distinguish from other bone disorders in the absence of typical symptoms such as the premature loss of primary teeth. Therefore, this study aimed to analyze the crystallinity of hydroxyapatite (HAp) and the three-dimensional structure of collagen in HPP teeth at the molecular level and to search for new biomarkers of HPP. Raman spectroscopy was used to investigate the molecular structure, composition, and mechanical properties of primary teeth from healthy individuals and patients with HPP. The results showed that the crystallinity of HAp decreased and the carbonate apatite content increased in the region near the dentin–enamel junction (DEJ) of HPP primary teeth. X-ray diffraction (XRD) analyses confirmed a decrease in HAp crystallinity near the DEJ, and micro-computed tomography (CT) scanning revealed a decrease in mineral density in this region. These results suggest incomplete calcification in HPP primary dentin and may contribute to the development of diagnostic and therapeutic agents.