Search Results (1,751)

Calcite habit engineering offers a route to transform CO₂ mineralization from bulk sequestration into value-added nanomaterial production. Here, we demonstrate that additive chemistry and seeding strategy can serve as separable, recipe-level levers for directing calcite habit formation within a unified CaO/Ca(OH)₂ gas–liquid carbonation platform. This strategy highlights how solution-mediated habit control can bridge fundamental calcite crystallization mechanisms with scalable CO₂ utilization and value-added carbonate nanomaterial production. Sodium glutamate yielded ~100 nm rhombohedral nanoparticles, staged MgSO₄/ZnSO₄ dosing produced whisker-like crystalline nanorods with aspect ratios of 4–7, and two-step seeded carbonation with NH₄Cl generated fusiform spindle subunits that assembled into hierarchical rosette architectures. X-ray diffraction confirmed calcite as the only crystalline calcium carbonate phase detected under the present measurement conditions, with no detectable aragonite or vaterite reflections. SEM/TEM revealed distinct primary-subunit architectures, including internal striations in spindle particles indicative of oriented attachment. Thermogravimetry, N₂ physisorption, and EDS further distinguished the products and showed that Mg/Zn/S modifiers in the whisker route are retained predominantly at crystal surfaces rather than incorporated into the calcite lattice. These results define calcite habit control through two independent levers: additive-driven facet selectivity and kinetic decoupling of nucleation from growth/assembly. The platform links scalable synthesis, CO₂ utilization, and functional carbonate design. Full article

Protein crystal nucleation remains difficult to predict and control and is still a critical issue in structural biology, protein crystal formulations, and crystal engineering. Heterogeneous nucleants can regulate protein crystallization by providing solid interfaces, enriching protein molecules, and stabilizing prenucleation aggregates; however, their dominant action stage, particle-size effect, and interfacial interaction mechanism remain unclear. In this study, hen egg white lysozyme (HEWL) was selected as a model protein, and silica nanoparticles (SNPs) with average diameters of 80, 120, and 200 nm were prepared using the modified Stöber method. Under a constant total particle surface area, the effects of SNPs on HEWL crystallization, prenucleation aggregation, interfacial adsorption, and subsequent crystal growth were systematically investigated. The results showed that, under 30 mg·mL⁻¹ HEWL and 0.6 M NaCl conditions, all SNPs shortened the apparent induction time, with 200 nm SNPs showing the strongest effect. In contrast, 80 nm SNPs produced the largest crystal size at the fixed observation time of 72 h, suggesting that crystal size within a fixed incubation period is jointly affected by nucleation rate, nucleus number, local solute consumption, and subsequent crystal growth. Under low protein concentration and low NaCl concentration conditions, SNPs promoted crystal formation in systems with weak spontaneous nucleation. Zeta potential, UV-Vis, fluorescence, FT-IR, CD, and DLS results suggested that SNPs interacted with HEWL at the interface and promoted apparent aggregation behavior, whereas polarized optical microscopy indicated no detectable influence on the later linear growth of visible crystals. These results suggest that SNPs mainly affect processes before visible crystal formation and provide insight into their application as heterogeneous nucleants for protein crystallization. Full article

Crystallization can be exploited as an architecture-forming step for polymer membranes because it builds a load-bearing semicrystalline scaffold while simultaneously defining amorphous regions that later become transport pathways. Herein, we quantify how thermal history programs isotactic polystyrene (iPS) crystallization and translate the resulting microstructures into membrane-relevant design rules. Lux-calibrated digitally extracted pixel intensity (DPI) from polarized optical microscopy provides a quantitative, spatially resolved crystallinity proxy; benchmarking against differential scanning calorimetry confirms that the DPI proxy exhibits the same onset, peak, and completion signatures under matched temperature programs. The DPI–DSC agreement yielded R² = 0.98 under matched programs. We compared crystallization initiated from molten and glassy states across a wide range of melt pretreatments and crystallization temperatures. Molten-state pathways display pronounced melt-memory behavior: modest changes in melt pretreatment shift induction time and half-time and drive textures from dense, fine spherulitic fields to sparse, coarser morphologies. In contrast, glassy-state crystallization largely suppresses melt history, yielding overlapping sigmoidal crystallinity curves and stable kinetic parameters consistent with relaxation-mediated nucleation. Avrami analyses indicate three-dimensional growth in both routes but highlight the strong melt-history sensitivity of apparent rate constants in the molten state. The crystallization rate and half-life show bell-shaped temperature dependence. Finally, saturated nucleation density correlates with the melting response, providing a practical link between kinetic observables and morphology. The processing–morphology map provides membrane-relevant design rules by linking thermal history to nucleation density and scaffold texture, which are expected to influence transport and mechanical stability in downstream membrane fabrication. In this study, “membrane architecture” is used in a pre-fabrication sense to denote the crystallization-programmed semicrystalline scaffold expected to govern subsequent pore-generation behavior and mechanical stability. Accordingly, the present work establishes a quantitative process–structure map for iPS scaffold design. Full article

We demonstrate the molecular beam epitaxy growth of two-dimensional van der Waals ferromagnet Fe₃GaTe₂ films with precisely controlled thicknesses down to a single unit cell. Magneto-optical Kerr effect microscopy measurements reveal robust room-temperature ferromagnetism with perpendicular magnetic anisotropy persisting across all thicknesses, including finite coercivity in monolayer films. The magnetic domain structures show strong thickness dependence: ultrathin films exhibit near-single-domain states without resolved domain nucleation or domain wall propagation, while thicker films develop complex multi-domain configurations featuring bubble-like domains. These findings underscore the pivotal role of dimensional confinement in modulating the magnetic properties of Fe₃GaTe₂ and provide critical insights into thickness-dependent phenomena in two-dimensional magnets, advancing their prospects for room-temperature spintronic applications. Full article

Traumatic brain injury (TBI) is increasingly recognized as a relevant initiating factor in tau-related neurodegenerative processes, yet the quantitative link between a controlled mechanical insult and the long-term spatiotemporal evolution of tau pathology remains insufficiently defined. In the present study, a translational computational framework is proposed to predict post-traumatic tau accumulation by combining region-specific Avrami-type nucleation-growth kinetics with a finite-element simulation of controlled cortical impact (CCI) at human scale. The temporal component of the model is calibrated independently for cortex, hippocampus, and brainstem using experimental post-TBI tau-burden measurements derived from a tau-transgenic mouse model of CCI. The formulation preserves anatomical specificity by calibrating each region independently. The biomechanical component is built around a localized indentation framework designed to mimic the experimental CCI configuration. To transfer the loading concept from mouse to human, the indenter geometry is scaled using cortical thickness as the primary characteristic length, ensuring that the local indentation problem remains mechanically interpretable across species. The resulting strain field is then normalized and used to distribute tau spatially within each region while preserving the calibrated regional mean kinetics. The proposed framework provides a region-aware and mechanically grounded route for studying how a controlled cortical insult may trigger heterogeneous tau accumulation over time, thereby offering a computational basis for investigating early mechanobiological pathways relevant to trauma-associated tauopathy and chronic traumatic encephalopathy (CTE). Full article

We show that halide evaporation during melt growth of ${\mathrm{CsPbBr}}_3$ on polycrystalline FTO under partially open conditions drives discrete phase selection between the line compounds of the CsBr–PbBr₂ system, producing a sharp ${\mathrm{CsPbBr}}_3/{\mathrm{CsPb}}_2{\mathrm{Br}}_5$ bilayer instead of compositional grading. In situ optical imaging shows that solidification begins with nucleation and lateral growth of a planar ${\mathrm{CsPbBr}}_3$ single crystal while the melt layer is still thick enough to average over the FTO relief. As the crystal thickens, the residual melt then becomes inhomogeneous and unstable, producing a buried porous layer of faceted ${\mathrm{CsPb}}_2{\mathrm{Br}}_5$ grains with a characteristic in-plane spacing of 1–10$\mathsf{\mu }\mathrm{m}$). This morphology is consistent with a faceted Mullins–Sekerka-type instability under a non-conservative evaporative boundary condition. Beneath the single-crystal cap, the first-formed faceted islands are large and become progressively smaller as the advancing front approaches the FTO pyramids, while elevated ambient halide partial pressure suppresses the instability, consistent with diffusion–capillarity selection under decreasing residual melt thickness and steepening local gradients, modified by evaporative flux. Oxygen associated with microvoids or the oxide substrate enables a secondary reaction–diffusion pathway forming Pb–Br–O crystallites without altering the primary length scale. These results identify evaporation as an active control parameter coupling phase equilibria and interfacial stability in volatile halide melts. In the buried, porous bilayer morphology observed here, the secondary phases and porosity reduce the active ${\mathrm{CsPbBr}}_3$ volume and are expected to degrade scintillation through increased trapping, nonradiative recombination, and light scattering. Full article

This study investigates the degradation and failure mechanisms of AISI 310S stainless steel conveyor belt wires operating under cyclic conditions up to 900 °C in a continuous carburizing furnace. Microstructural evolution and mechanical responses after service exposure were evaluated using optical microscopy, scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Vickers microhardness testing. Results indicate that initial exposure led to $\sigma$-phase nucleation and the formation of a protective Cr₂O₃-SiO₂ oxide scale. However, prolonged service led to scale degradation driven by Na-containing residues from pre-cleaning agents, which reacted to form Na₂SiO₃ and NaAlSiO₄ phases. This degradation accelerated the growth of non-protective iron oxides (Fe₂O₃, Fe₃O₄). Simultaneously, the $\sigma$-phase decomposed into massive, continuous M₂₃C₆ and M₇C₃ carbide networks along grain boundaries, inducing severe chromium sensitization. Consequently, the matrix embrittled significantly, with Vickers hardness increasing from 150 HV to 290–340 HV. Fracture analysis confirmed that brittle intergranular cracking initiated at these carbide networks, oxide inclusions, and matrix pores. Ultimately, the synergistic effects of oxide scale degradation, extensive carbide precipitation, and grain boundary depletion caused the premature catastrophic failure of the conveyor mesh under cyclic operational stress. Full article

This study provides a comprehensive characterization of carbon dust adhesion on the anode surface induced by the anode effect (AE) in the Hall–Héroult process. The primary objective was to verify the hypothesis of electrophoretic carbon particle transport and its subsequent stabilization on the electrode substrate. Unlike previous studies conducted in horizontal configurations where gravitational sedimentation could interfere with observations, this research employs a unique vertical electrode setup to provide direct physical evidence of purely electrophoretic transport. Authentic industrial carbon dust was used as a tracer material, its presence on the high-purity graphite surface being definitively confirmed through the detection of trace markers (Mg, Ca) via SEM-EDS. The multiscale structural analysis revealed that spike initiation occurs through a dynamic arc-induced nucleation mechanism. Morphological observations suggest that micro-arc discharges during the AE provide the extreme localized energy for direct carbon-to-carbon “welding,” creating a conductive, porous scaffold on the vertical anode wall. XRD analysis identified crystalline cryolite (Na₃AlF₆) and chiolite (Na₅Al₃F₁₄) within this structure. It was demonstrated that these fluoride phases represent the solidified product of molten, acidic electrolyte infiltration into the carbonaceous matrix via capillary action, rather than acting as binders that crystallize during the process. Raman spectroscopy confirmed the disordered, amorphous nature of the captured dust (high D-band intensity), distinguishing it from the highly ordered graphite substrate. Confocal microscopy visualized the topographical evolution from isolated clusters to interconnected three-dimensional “islands” as a function of AE duration. The results demonstrate that the anode effect serves as a critical flashpoint where synergistic electrophoretic forces and localized thermal anomalies initiate the growth of stable, conductive carbon–matrix composite spikes, providing new insights for mitigating current efficiency losses in industrial smelters. Full article

This review focuses on the effects of trace and residual rare-earth elements on inclusion evolution and Nb–Ti–V precipitation behavior in microalloyed steels. Existing studies indicate that trace rare-earth elements can transform conventional Al₂O₃- and MnS-type inclusions into rare-earth oxides, oxysulfides, and sulfides, while also modifying local interfacial states and solute distributions through segregation and interfacial activity. These changes further affect the nucleation sites, growth behavior, coarsening tendency, and spatial distribution of NbC, TiN, VC, and related carbonitrides. To explain the seemingly contradictory precipitation responses reported in the literature, this review examines rare-earth effects from the perspectives of inclusion inheritance, heterogeneous nucleation, interfacial energy modification, local solute redistribution, and thermomechanical processing history. The available evidence suggests that the metallurgical role of trace rare-earth elements cannot be attributed solely to inclusion modification. Instead, their effects arise from the combined influence of inclusion evolution, interfacial activity, local chemical heterogeneity, and precipitation kinetics under specific processing conditions. These insights provide practical guidance for alloy and process design by linking rare-earth addition, inclusion control, and Nb–Ti–V precipitation regulation in microalloyed steels. Full article

High-index silicon surfaces provide anisotropic step networks, reconstruction states, and facet-adjacent geometries that can modify the first stages of III–V heteroepitaxy. This critical review examines GaAs/AlGaAs growth on Si$\left(hhl\right)$ surfaces, with emphasis on the coupled roles of substrate orientation, surface preparation, first-monolayer initiation, and molecular beam epitaxy kinetics. The central viewpoint is that high-index Si can act as an active interfacial template: its anisotropy can bias early nucleation, relaxation, and faceting pathways before any intentional lithographic patterning is introduced. The discussion is anchored in two recent GaAs/Si studies. The first is a matched-condition benchmark comparing Si(001), Si(113), Si(111), and Si(331) under Ga-first and As-first initiation. The second is a Si(331) case study in which Ga pre-exposure followed by low-rate GaAs nucleation yields laterally ordered nanocorrugation/faceting and measurable in-plane optical anisotropy under the explored conditions. Surface-science precedents from adsorbate-induced reconstructions provide additional context for treating the first atomic layer as a meaningful growth variable. These studies point to a broader opportunity: using high-index Si$\left(hhl\right)$ surfaces to link interface chemistry, anisotropic morphology, structural relaxation, and optical response within a common framework for GaAs/Si integration. Full article

This paper investigates the valorization of peanut shell powder (PSP), an abundant agro-industrial residue, as a biofiller for the development of sustainable 3D printable PLA-based composites for food packaging applications. A low-filled biocomposite containing 2.5 wt.% PSP was successfully processed into filament with dimensional tolerances suitable for fused deposition modeling printing. Thermal and melt flow analyses demonstrated that PSP marginally reduced the thermal stability of PLA while preserving its thermal transition temperatures and increasing the melt flow rate up to 51%. Differential scanning calorimetry revealed a slight increase in crystallinity in biocomposite filament compared to neat PLA pellets, mainly associated with thermo-mechanical processing of the extrusion, while the lower crystallinity degree relative to PLA extrudate suggested a negligible nucleating effect of PSP. To optimize print quality, different extrusion temperatures and infill flow rates were evaluated. The best mechanical performance was achieved at 200 °C and 130% flow rate, where reduced inter-filament porosity (5.2%) resulted in improved tensile strength and stiffness compared with the other printing conditions. Although mechanical properties remained lower than neat PLA, the material proved suitable for non-structural packaging applications. Prototype packaging boxes were fabricated and tested for the storage of fresh-cut melon. Compared with neat PLA packaging, the PLA-PSP system better preserved fruit firmness over 10 days, inhibited fungal growth, and delayed visible deterioration, highlighting the potential active role of PSP in food preservation. Anaerobic biodegradation tests conducted under mesophilic conditions confirmed that the addition of PSP did not hinder PLA biodegradability and slightly enhanced methane production. Overall, the results demonstrate that peanut shell waste can be effectively upcycled into functional 3D-printable biocomposites for sustainable packaging solutions. Full article

Crystal size distributions (CSDs) of metamorphic minerals provide quantitative constraints on nucleation-growth kinetics and metamorphic thermal regimes. Early interpretations linked CSD shape to type of metamorphism, associating near-linear CSDs with rapid-contact metamorphism and bell-shaped CSDs with prolonged regional metamorphism. Subsequent works showed that diffusion-controlled nucleation and growth can also produce bell-shaped CSDs without annealing, leaving unresolved how contrasting thermal regimes are expressed in interface-controlled systems. The Fangshan tectonic dome at the northern margin of the North China Craton comprises multiple metamorphic zones, recording Mesozoic contact metamorphism of Fangshan plutons and a concealed pluton in the Nanjiao area. We employed high-resolution X-ray micro-computed tomography (micro-CT) to quantify the 3D crystal size distributions of garnets of contact metamorphic samples from the Nanjiao area and the Fangshan contact aureole. Integrated 3D CSDs with spatial statistics, reconstructed nucleation curves, garnet compositional zoning, and thermodynamic phase equilibrium modeling were used to decipher crystallization kinetics in interface-controlled systems. Nucleation and growth of garnets from the Nanjiao area, and one sample from the Fangshan contact aureole, which is separated from the main heat source by an earlier intruded magma body, are interface-controlled, and display bell-shaped CSDs together with sigmoidal nucleation curves that record a progressive increase followed by a gradual decline in nucleation rate. Phase equilibrium modeling and garnet compositional profiles of a sample from Nanjiao demonstrate that the late-stage deceleration of nucleation in interface-controlled systems is fundamentally driven by whole-rock constituents’ exhaustion rather than the geometric impingement of diffusion halos. In contrast, another contact sample, which is collected near the main heat source, is diffusion-controlled, and displays a steep J-shaped nucleation curve with a delayed, broad peak nucleation rate followed by rapid late-stage suppression. The 3D textures of these metamorphic rocks suggest that contact and regional thermal regime alone do not determine garnet population characteristics; bell-shaped CSDs can be produced in contact metamorphic environments. We propose that heating rate is the primary control on the resulting crystal size distributions. Full article

Copper azides are promising energetic materials for miniaturized pyrotechnic devices and micro explosive trains owing to their short detonation growth distance and high initiation energy. However, controllable preparation of copper nanoparticle precursors and their in situ conversion to copper azides under mild conditions remains challenging. In this study, copper nanoparticles were synthesized via a coordination-assisted aqueous reduction method at room temperature under air atmosphere using nitrilotriacetic acid disodium salt (NTA·H·2Na) as the complexing agent. The resulting nanoparticles were pressed into polyester rings to construct confined precursor structures, and copper azide micro-charges were prepared through in situ gas–solid reaction with HN₃ gas generated from NaN₃ and concentrated phosphoric acid at 60 °C. SEM characterization revealed that the morphological evolution of copper azides followed a three-stage pattern: “product island nucleation, branch/block coalescence growth, and continuous product layer formation and structural reconstruction”. Detonation velocity tests using the electrical probe method showed an average value of (5.10 ± 0.07) × 10³ m/s. Flyer impact initiation tests demonstrated that, with a charge thickness of 1.00 mm, both a 30 μm polyimide flyer and a 40 μm titanium flyer could successfully initiate a HNS–IV explosive. The preparation methodology and performance characterization established in this work provide an experimental basis for the application of copper azides in micro-initiation systems. Full article

The results of a multiscale study of fault and fracture geometry, distribution, density, and intensity are reported for Mesozoic platform carbonates cropping out along the axial zones of the southern Apennines fold-and-thrust belt, Italy. By integrating field structural observations with digital outcrop analysis, the study focuses on Cretaceous limestone rocks exposed along natural creeks and artificial trails of the Castelsaraceno area, Raparo Mt., southern Italy. There, the limestone beds are bounded by mm- to cm-thick marly–clayey interbeds, forming a well-layered succession made up of a few m-thick bed packages bounded by several cm-thick clayish interlayers. The carbonate multilayer was first affected by thrust tectonics, with the formation of low-angle intra-carbonate thrust faults and fault bend-folding. Then, the multilayer was crosscut by extensional–transtensional high-angle faults, which displaced the previously formed contractional structural elements, and allowed carbonate exhumation from shallow crustal depths. At outcrop scales, thrust-related deformation was solved by low-angle joints and veins, rare high-angle stylolites, and low-angle sheared fractures displaying reverse kinematics. Quantitative analyses of fracture density (P20) and intensity (P21) conducted on selected portions of the thrust fault zones indicate that the low-angle joints and veins attain their highest values in the vicinity of the main slip surfaces, whereas they are almost absent in the surrounding carbonate host rocks. Plio-Quaternary transtensional deformation was solved by NW–SE- and NE–SW striking faults. The latter fault set, nicely exposed along the flanks of the Raganello Creek, was characterized by right-lateral components of slip. Incipient faults, with ca. 1 cm throw, are made up of vertically discontinuous slip surfaces, which crosscut single bed packages and abut against clayish interlayers. The slip surfaces form conjugate geometries, and are associated to high-angle fractures and veins striking NE–SW, dissecting the bed packages. The fault core is virtually absent, whereas the damage zones are very discontinuous along dip. The P20 values computed for the high-angle fractures and veins increase toward the slip surfaces, whereas the P21 values remain nearly constant. These data are interpreted as being due to fault nucleation processes associated with fracture nucleation within the limestone rocks. NE–SW striking small faults displaying throws between 10 and 60 cm are comprised of through-going main slip surfaces crosscutting multiple bed packages, and poorly developed, discontinuous fault cores flanked by m-thick damage zones. The damage zones include sub-parallel high-angle shear fractures, fractures and veins showing a positive correlation between P20 and P21, whose values increase in the vicinity of the main slip surfaces. Such a positive correlation is interpreted as due to fault growth by linkage and coalescence of pre-existing high-angle fractures, and formation of fault-related joints and veins at the extensional quadrants of single shear fractures. Similarly, large-scale NE–SW striking mature faults with throws on the order of tens of meters, made up of a m-thick fault core and 10 s of m-thick damage zones including sub-parallel fractures and veins, also show a positive P20 and P21 correlation. The main outputs of this work are synthesized into a conceptual model illustrating the transition from thrust-related deformation to extensional–transtensional faulting, documenting the evolution of fracture networks from incipient-to-small-to-mature faults. Full article

Six different twin boundary interface models were constructed by molecular dynamics simulations to investigate the effect of biaxial load ratio on the fracture behavior of titanium twin boundaries. Analysis of microstructural evolution indicates that twin boundaries exhibit a dual role during crack propagation. On one hand, they serve as preferential sites for void nucleation, promoting crack propagation along the twin boundary; on the other hand, they provide favorable sites for dislocation nucleation, inducing local plastic deformation at the crack tip, altering the crack path, and thereby hindering crack propagation. The crack propagation behavior in the ($\overline{1}0$11) and ($\overline{1}0$13) twin boundary models shows evident asymmetry: the crack on the left side mainly propagates through the void nucleation mechanism and exhibits a faster growth rate, while the right-side twin boundary inhibits crack propagation by favoring dislocation nucleation. In contrast, the crack propagation behavior in the ($\overline{1}0$12), ($\overline{2}1$11), ($\overline{2}1$12) and ($\overline{2}1$14) twin boundary models is largely symmetric on both sides, showing no significant difference in propagation rate. Stress field analysis further reveals that the differences in crack propagation behavior among the various twin boundary models mainly originate from the disparity in dislocation activity on both sides of the crack, resulting in different levels of stress concentration at the crack tip. When void nucleation occurs at the twin boundary interface, the stress concentration between the main crack and the void intensifies, promoting their coalescence and further propagation. Meanwhile, with an increase in biaxial load ratio, the stress concentration at the crack tip becomes more pronounced, further accelerating crack propagation. Full article