Search Results (5,425)

We compare the ionic transport properties of six LiFeO₂ polymorphs side by side to assess their potential as intercalation cathodes for lithium-ion batteries (LIBs). Employing two established methods, Bond Valence Site Energy (BVSE) calculations and Crystal Analysis by Voronoi Decomposition (CAVD), with identical settings for all six structures, we analyze how structural variations affect Li-ion diffusion pathways, dimensionalities, and migration barriers. Within this comparison, the ordered rock salt phase shows the most favorable transport characteristics, combining the lowest energy barriers of the six polymorphs with three-dimensional Li-ion conduction. The tetrahedral polymorph also has a three-dimensional void network, but its lowest-energy migration is one-dimensional, and the network connects in all three dimensions only at considerably higher energy. In contrast, layered and corrugated structures enable quasi-two-dimensional diffusion but are limited by high out-of-plane barriers. The goethite and $\gamma$ phases are the most constrained. Goethite confines low-energy migration to a single axis, and in $\gamma$-LiFeO₂, high barriers in every direction leave the geometrically connected network kinetically ineffective. Together, the results provide a consistent structure–transport comparison across the six polymorphs that can guide the choice of LiFeO₂ phases for further cathode development. Full article

Fischer–Tropsch (FT) wax is widely used as an organic warm-mix asphalt (WMA) additive, lowering binder viscosity during construction while improving high-temperature deformation resistance in service; however, the comparative responses of SBS-modified asphalt to different FT wax grades remain insufficiently understood. Sasobit and three FT waxes with different carbon-chain ranges (FT 80, FT 90, FT 100) were incorporated into SBS-modified asphalt at about 7.0 wt%, and their effects on macroscopic performance, rheology, molecular packing, and diffusion were evaluated using physical-property tests, rotational viscosity, dynamic shear rheometer (DSR) testing, and molecular dynamics (MD) simulation. In the MD analysis, the wax additives were represented by linear alkane molecules with different chain lengths, and the systems were subjected to structural optimization, annealing, and NPT equilibration using the COMPASS III force field before the molecular descriptors were evaluated. The experimental results showed that all four additives produced a trade-off between increased high-temperature stiffness and reduced low-temperature ductility. Sasobit gave the strongest viscosity reduction (>70% above 165 °C), while FT 90 and FT 100 showed more stable, predictable viscosity–temperature behavior favorable for a wider construction window. DSR results showed higher complex modulus and lower phase angle for all modified binders at low frequencies, suggesting an increased elastic contribution and greater resistance to deformation under the tested rheological conditions; FT 80 produced the greatest stiffening but also the largest free volume and loosest molecular packing, whereas FT 100 increased cohesive energy density and reduced free volume, reflecting denser packing and stronger intermolecular cohesion. MD simulations revealed that FT wax enhanced short-time local molecular mobility and segment diffusion in its molten state (explaining the warm-mix viscosity reduction), whereas macroscopic stiffening and ductility loss at ambient temperatures were dictated by wax microcrystallization and physical network constraints that restricted long-range chain relaxation. By comparing three FT wax grades and Sasobit under the same experimental dosage and testing framework, this study provides a controlled assessment of the relationships among wax-grade characteristics, binder-scale rheological responses, and MD-derived molecular descriptors. Full article

The development of high-performance anode materials remains a key challenge for advancing lithium-ion battery (LIB) technology. In this work, an oxy-bridged polymer cobalt phthalocyanine (Poly-CoPc) and its single-walled carbon nanotube-modified composite (Poly-CoPc/SWCNT) were successfully synthesized and systematically investigated as potential anode materials. The structural, chemical, and morphological properties of the materials were thoroughly characterized using Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM) techniques. Morphological studies demonstrated a uniform dispersion of Poly-CoPc over the SWCNT network, leading to an interconnected conductive structure with enhanced surface area. Electrochemical performance was evaluated and compared with pristine Poly-CoPc. Compared to pristine Poly-CoPc, the Poly-CoPc/SWCNT composite exhibited significantly improved electrochemical behavior, including higher specific capacity, enhanced rate performance, and superior cycling stability. The composite delivered a high initial discharge capacity of 2016 mA g⁻¹ and maintained an excellent reversible capacity of 1047 mA g⁻¹ after 100 cycles at 0.1 A g⁻¹. Furthermore, it demonstrated outstanding rate capability, retaining a capacity of 855 mA g⁻¹ at 0.5 A g⁻¹. This enhanced performance is attributed to the synergistic effect between the redox-active Poly-CoPc and the highly conductive SWCNT network, which facilitates efficient electron transport, improves ion diffusion, and stabilizes the electrode structure during cycling. These results highlight that SWCNT-modified Poly-CoPc is a promising candidate for next-generation high-performance LIB anodes. Full article

Microalgal growth-promoting bacteria (MGPBs) represent a promising strategy to enhance biomass productivity, yet the mechanistic basis of these mutualistic interactions remains poorly understood. Here, we isolated a new MGPB, Cupriavidus oxalaticus MEYA8, and characterized its mutualistic interaction with the model microalga Chlamydomonas reinhardtii. Co-cultivation at an optimal MEYA8: Chlamydomonas ratio greatly enhanced microalgal cell density and chlorophyll content, which reached 2.1-fold and 1.6-fold those of the control, respectively, with markedly improved photosynthetic efficiency across both photosystems. Transwell assays confirmed that this promotion is mediated by diffusible metabolites rather than direct cell contact. Metabolites and multi-omics analyses revealed that MEYA8 can produce compounds similar to indole-3-acetic acid (IAA) and is adapted to the microalgal phycosphere by preferentially utilizing organic acids and amino acid derivatives. In response, Chlamydomonas upregulated proteins involved in photosynthetic electron transport, energy metabolism, and nitrogen assimilation, consistent with the observed enhancement in photosynthetic performance. These findings suggest a metabolically reciprocal interaction model: MEYA8 supplies diffusible growth-promoting factors such as IAA-like compounds to enhance Chlamydomonas photosynthesis and growth, while Chlamydomonas provides organic substrates that sustain bacterial proliferation. Our work provides new insights into algal–bacterial mutualism and may provide a new microbial resource for engineering microalgal and beneficial bacterial consortia. Full article

Blending hydrogen into existing natural-gas pipeline networks provides a practicable route toward future low-carbon applications. A Venturi-type mixer is a classical high-efficiency static gas-mixing device, and clarifying the effects of its structural parameters is important for efficient transport and downstream combustion stability. In this study, numerical simulations were performed in ANSYS Fluent 2024 R1. The contraction angle, throat length, and diffuser angle were selected as representative structural variables. First, the independent effects of these variables on the mixing process were examined through single-factor simulations. Then, three key levels of the three structural parameters were selected to establish a Box–Behnken experimental matrix for response-surface modeling. Based on the numerical results, entropy weighting and a genetic algorithm were used for multi-objective optimization, and the final solution was verified using the TOPSIS method. The results show that the optimized Venturi-type mixing device with optimized parameters of a contraction angle of 20.7°, a throat length of 60 mm, and a diffuser angle of 5° can reduce flow energy loss while maintaining high mixing uniformity. The diffuser angle is the dominant geometric parameter affecting both energy loss and mixing behavior. Compared with the reference central-point structure design, the overall TOPSIS score of the optimized structure increased from 0.41 to 0.82; the pressure loss decreased from 258.94 Pa to 206 Pa, corresponding to a reduction of approximately 20%; and the final-section mixing uniformity decreased only slightly, from 97.85% to 97.43%. Full article

The effect of internal pressure on the layered microstructural evolution of N36 zirconium alloy cladding tubes was systematically studied under simulated loss-of-coolant accident (LOCA) biaxial creep conditions at 900 °C. The tested specimens were characterized by electron channeling contrast imaging, energy-dispersive X-ray spectroscopy, electron backscatter diffraction, and transmission electron microscopy. The results show that all specimens formed a typical layered cross-sectional structure consisting of an oxide film, an oxygen-rich α-Zr (α(O)) layer, and a prior-β transformed layer. The thickness of the α(O) layer and the oxygen diffusion depth changed markedly with internal pressure. The thickness of the α(O) layer was approximately 21 μm for the 0.8 MPa specimen and 11 μm for the 1.9 MPa specimen, respectively. The lower-pressure specimen exhibited a wider oxygen-affected region, whereas the higher-pressure specimen showed a steeper oxygen gradient. In the prior-β transformed layer, lath-like α structures formed under both conditions, but their spatial arrangement and orientation distribution were different. Under lower internal pressure, the laths were more regularly arranged and showed a more complete colony structure. Under higher internal pressure, the laths were more interwoven, and the orientation distribution became more scattered. Meanwhile, the high-pressure specimen retained a higher local orientation gradient and a higher degree of lattice distortion. These results indicate that the above microstructural differences mainly arise from the effect of internal pressure on the high-temperature exposure history. A higher internal pressure causes earlier instability of the specimen, thereby shortening the effective time for oxygen diffusion and microstructural evolution, rather than directly changing the oxidation or phase transformation process. Full article

We examine energetic electron distributions in the region of the diffuse aurora using a two-dimensional bi-Maxwellian model, applied to electron flux data at a single geomagnetic equator (L = 6.5). Electron flux is analyzed as a function of energy and pitch angle and transformed into velocity space to reconstruct the distribution function. An unweighted log-space least-squares fit of the bi-Maxwellian model to the reconstructed distribution yields a reduced residual measure of ${\chi }_v^2=1.000053$, a mean absolute residual of $|\Delta {\log }_{10}f|=0.0469$ dex, an anisotropy factor, $A_T=0.9886\pm 0.0016$, and no statistically significant bulk drift. These results show that, at this location, the bi-Maxwellian model reproduces the observed velocity-space structure with good quantitative accuracy and reveals a quasi-isotropic, near-equilibrium electron population. Full article

Laser-based Optical Wireless Power Transmission (OWPT) enables highly directional long-distance energy delivery. However, atmospheric turbulence near the ground significantly degrades transmission efficiency, particularly during daytime when beam scintillation becomes more severe. In this study, a diffractive optical element (DOE) was employed at the transmitter for beam shaping, while receiver-side disturbance mitigation was achieved using a transmissive diffuser-based homogenizer, a reflector-based optical confinement structure, and a bypass-capacitor-based smoothing circuit. Photovoltaic (PV) cells fabricated by laser cutting commercially available crystalline silicon solar cells were connected in series to construct a 600 mm × 600 mm PV panel. Without receiver-side disturbance mitigation, the output power decreased by more than 50% as the atmospheric structure constant (Cn²) increased from 10⁻¹⁴ to 10⁻¹³ m^−2⁄3. In contrast, the proposed receiver-side techniques effectively suppressed turbulence-induced performance degradation and maintained nearly constant output power. Furthermore, the combination of the homogenizer and the smoothing circuit increased the receiver output power by approximately a factor of 2.2 under a turbulence condition of Cn² ≈ 3 × 10⁻¹⁴ m^−2⁄3. Using these techniques, 150 W of electrical power was generated over a 1 km outdoor optical link with a 1035 W, 1070 nm near-infrared laser. These results demonstrate that receiver-side disturbance mitigation is an effective approach for improving the efficiency and stability of practical long-distance OWPT systems. Full article

Natural gas hydrates, with their vast reserves and high gas storage density, have emerged as a highly promising alternative energy source and technology for gas storage and transportation. Wettability, as a core surface property of porous media, directly influences hydrate nucleation, growth, occurrence morphology, and flow behavior. In this study, quartz sand with varying surface properties was prepared with the octyltrimethoxysilane (OTMS) silane coupling agent via surface chemical reactions. The methane hydrate (MH) equilibrium conditions as well as the formation kinetics in silica sand were measured, and the mechanism and potential of the surface modification for enhancing methane hydrate storage capacity were analyzed. The experimental results indicate that surface modification of quartz sand has no significant effect on the MH equilibrium condition. Hydrophobic modification of quartz sand provides more gas–liquid interfaces, increases the contact area, and thereby significantly enhances mass transfer under high-water-saturation conditions and accelerates the MH formation rate. However, excessively high surface hydrophobicity may reduce the effective gas–liquid interfacial area and limit the overall hydrate formation rate. Due to the influences of the hydrate distribution and aggregation, as well as gas diffusion on hydrate formation, the effect of the initial formation pressure on MH formation is only observed during the early stages of MH formation, while the temperature effect is less pronounced than that of formation pressure. It is suggested to further consider combining stirring with continuous gas injection to enhance gas–liquid flow and improve gas–liquid contact, thereby increasing the formation rate of hydrates. Full article

This study investigates the effect of carbon nanotube (CNT) addition on the densification behavior, activation energy, microstructural evolution, and mechanical performance of WC-Co cemented carbides processed by liquid-phase sintering. WC-Co and WC-Co reinforced with 5 vol.% CNT were fabricated by powder metallurgy and sintered under argon atmosphere at temperatures between 1380 and 1400 °C using different holding times. Relative density measurements, dilatometric analysis, scanning electron microscopy, and Vickers hardness and fracture toughness evaluations were performed to assess the influence of CNT incorporation on the sintering response and resulting microstructure. The results showed that increasing sintering temperature and holding time promoted densification and microstructural consolidation in both systems. Although CNT addition slightly reduced the final relative density, it promoted a finer and more homogeneous carbide distribution. Dilatometric analysis revealed that CNT incorporation modified the densification kinetics and increased the apparent activation energy from 99.36 ± 8 kJ/mol for WC-Co to 126.47 kJ/mol for WC-Co + 5 vol.% CNT, corresponding to an increase of approximately 27%, indicating significant changes in the diffusion-controlled mass transport mechanisms governing liquid-phase sintering. Furthermore, the CNT-reinforced material exhibited improved mechanical performance, reaching hardness and fracture toughness values of approximately 1090 kgf/mm² and 10.5 MPa·m^1/2, respectively, compared with 995 kgf/mm² and 8.6 MPa·m^1/2 for the unreinforced WC-Co system. Enhanced fracture resistance was further supported by reduced crack propagation after Vickers indentation. The results demonstrate that CNT incorporation acts not only as a reinforcing phase but also as a microstructural and kinetic modifier, providing an effective strategy for controlling densification behavior and improving the performance of WC-Co cemented carbides processed by liquid-phase sintering. Full article

Node classification is a central graph data mining task, yet repeated message passing can over-smooth representations and degrade frozen graph neural network (GNN) predictions after deployment. We present SETTA (Spectral-Energy Test-Time Adaptation), a prediction-level graph test-time adaptation framework that refines frozen outputs without test labels, gradients, parameter updates, or learnable adaptation parameters. SETTA denoises features for semantic-neighbor construction, adds complementary semantic routes while preserving observed edges, monitors a smoothness-energy proxy during diffusion, and accepts refinements through entropy-based gating. Configurations are fixed by a dataset-level protocol or selected using validation data only. Across six mostly homophilic benchmarks with 2708–19,717 nodes, SETTA improved a frozen two-layer GCN on every dataset and achieved the highest mean accuracy among the evaluated methods on five, with gains of 4.61, 3.08, and 2.01 percentage points on Cora, CiteSeer, and PubMed, respectively. Positive mean gains were also observed across all 30 dataset–backbone settings. Ablations and transition analyses indicate that semantic injection is most beneficial on sparse citation graphs and that selective refinement limits harmful changes. The current dense implementation supports benchmark-scale, amortized refinement; scalability and robustness on heterophilic graphs remain open. Full article

This study investigates the atomic-scale effects of hydrogen concentration and Ni content on crack propagation in Fe-Ni alloy models using molecular dynamics methods. A Mode I crack model with a (001)[100] orientation was constructed, and hydrogen atoms were locally introduced at the crack tip with concentrations of 5.3 at.% and 14.3 at.%. Fe-Ni alloy models with 5%, 10%, 15%, and 20% Ni were compared in terms of crack growth, dislocation evolution, stacking fault energy, and hydrogen diffusion. The results show that local hydrogen introduction has a limited effect on the peak stress–strain response, while hydrogen clearly accelerates crack propagation in the middle stage, especially at high concentrations. For the 10% Ni model, the middle-stage crack growth rate increases to 0.36 Å/ps under 14.3 at.% crack-tip hydrogen. Crack growth in all models shows three stages. The 15% Ni model exhibits a clear plateau in the second stage and the shortest final crack length. Further analysis shows that Ni content regulates dislocation behavior through stacking fault energy. At 15% Ni, sustained dislocation entanglement and high-density dislocation multiplication occur near the crack tip, which helps dissipate local stress. Hydrogen diffusion analysis indicates that hydrogen mobility is lower in the 15% Ni model, which may be related to hydrogen retention near dislocation-rich regions. A normalized comparison based on hydrogen diffusion and middle-stage crack growth rate further identifies 15% Ni as the lowest crack propagation tendency composition among the studied models. These results provide atomic-scale data for Ni-content optimization in hydrogen-resistant alloys, although the direct engineering transfer of the findings is limited by the length and time scales of molecular dynamics simulations. Full article

In this study, the author investigated the wake characteristics of a shrouded wind turbine and performed a high-resolution large-eddy simulation (LES) investigation using a supercomputer. The turbulent kinetic energy (TKE) of the shrouded wind turbine was significantly greater than that of a conventional wind turbine (non-shrouded wind turbine) in the range of x/D = 0 to 5 (where x is the distance downstream of the hub center and D is the rotor diameter), due to large-scale vortices generated and released from the brim of the shrouded wind turbine and the separated flow from the nacelle. For example, the TKE was 4.4 times larger at x/D = 2. Significant differences were also observed in the wake width. The wake width of the shrouded wind turbine was approximately 2.4 times wider than that of the conventional wind turbine. In contrast, the shrouded and conventional wind turbines exhibited nearly similar behaviors in the far-wake region downstream of x/D = 5. Furthermore, a calculation was performed for the shrouded wind turbine while omitting the brim connected to the diffuser. While flow separation from the diffuser is clearly observed, the numerical results for the shrouded wind turbine without the brim connected to the diffuser showed a flow pattern very similar to that of a conventional wind turbine. Full article

Developing fiber-shaped supercapacitors (FSCs) with high capacitance, high energy density, and exceptional rate performance is crucial for reliable, stable and high-performance wearable electronics. Here, a polyaniline (PANI) @ MXene Ti₃C₂T_x/graphene (PTG) aerogel fiber was rationally fabricated via a confined hydrothermal method followed by freeze-drying treatment. The graphene sheets construct the skeleton of the aerogel fiber, which possesses a porous and interlinked structure, providing interconnected diffusion channels and a high specific surface area that promote electrolyte migration and abundant ion adsorption sites. Moreover, the covalent modification between PANI nanoparticles and Ti₃C₂T_x sheets can significantly improve interfacial coupling and provide abundant redox sites, resulting in a reduced energy barrier of electron transfer, good interfacial stability and superior H⁺ storage capability. As a consequence, the PTG aerogel fiber electrode delivers an excellent specific mass capacitance of 484.8 F g⁻¹, impressive rate properties (244.4 F g⁻¹ at 10 A g⁻¹) and exceptional cycle ability (85.2% after 5000 cycles). Additionally, the fabricated symmetrical FSC exhibits considerable electrochemical performance, including high capacitance and good energy density. This work depicts a novel route to prepare a graphene fiber-based electrode for high-performance FSCs in an intelligent wearable system. Full article

Artificial intelligence (AI) is increasingly recognised for its transformative implications for sustainability transitions. Yet little is known about how AI co-evolves with green technological innovation systems and whether institutional adaptation keeps pace with technological diffusion. This study maps 3357 peer-reviewed publications between 2003 and 2025 using transformer-based topic modelling and cross-model triangulation to characterise structural evolution across enabling technologies, sectoral applications, and governance domains. Results reveal a reproducible triadic configuration consistent with innovation-system layering, alongside pronounced asymmetry in growth trajectories. While AI-enabled application domains (e.g., energy systems, waste and circularity, agriculture, and urban mobility) exhibit sustained expansion and increasing specialisation, governance and institutional strands demonstrate thinner density, greater model sensitivity, and delayed acceleration. These patterns are consistent with an asynchronous relationship between technological capability and institutional oversight, echoing the innovation-regulation lag observed in other technology-diffusion processes. The findings contribute to technological change literature by providing systematic evidence on the thematic structure and evolution of AI-enabled sustainability research and by proposing a co-evolution diagnostic framework for monitoring alignment between technological expansion and governance attention. Full article