Search Results (7,423)

Understanding the spatiotemporal evolution of rural settlements in ethnic minority regions is essential for coordinated rural development, cultural landscape conservation, and rural revitalization. Taking Fuxin Mongolian Autonomous County in Northeast China as a case study, this study examined rural settlement patterns and their driving mechanisms from 2000 to 2024 using GIS-based spatial analysis, landscape pattern metrics, and the optimal parameter-based geographical detector (OPGD) model. A multidimensional indicator system was constructed from four dimensions: natural environment, production-resource environment, ethnic–cultural environment, and socioeconomic environment. The results show that rural settlements remained significantly clustered, although clustering gradually weakened, with average nearest-neighbor ratios increasing from 0.7729 in 2000 to 0.8370 in 2024. High agglomeration was mainly concentrated in the southern and southeastern areas, whereas low agglomeration occurred in the western and northwestern areas. Annual average temperature had the strongest explanatory power (q = 0.2492), followed by road network density (q = 0.1786) and elevation (q = 0.1716), indicating that thermal conditions, transportation accessibility, and topographic constraints were dominant drivers. All two-factor interactions showed enhancement effects, suggesting a coupled rather than single-factor mechanism. Ethnic–cultural variables had relatively lower q-values but remain important for interpreting cultural continuity, heritage conservation value, and differentiated rural development. Full article

To improve the high-temperature service performance of cladding layers on DD5 single crystal superalloy, this study comparatively investigated the effects of two cobalt-based filler wires, PMet931 and PMet994, on the microstructural evolution, hardness, high-temperature tensile properties, and friction and wear behavior of the cladding layers. The results show that PMet931, with a higher Ni content, exhibits better compositional compatibility and interfacial metallurgical compatibility with the DD5 Ni-based substrate. In contrast, the higher W, C, and Cr contents in PMet994 promote the formation of W/Cr-rich secondary phases and grain refinement, resulting in higher hardness and better high-temperature strength retention. Both filler wires can form continuous cladding layers on the DD5 surface. The PMet931 cladding layer shows a more homogeneous microstructure and a smoother interfacial transition, whereas the PMet994 cladding layer contains more secondary phases and exhibits more pronounced strengthening features. Mechanical testing indicates that PMet931 provides a better strength ductility balance at room temperature, while PMet994 shows higher strength and hardness retention over the range of 800–1050 °C, with a tensile strength at 1050 °C approximately 53% higher than that of PMet931. The friction and wear results show that the wear rate of the PMet994 cladding layer was significantly lower than that of the PMet931 cladding layer at 800 °C, whereas the difference between the two cladding layers decreased at higher temperatures. This study demonstrates that filler wire composition significantly affects the high-temperature performance of DD5 cladding layers by regulating secondary phase precipitation, interfacial compatibility, and microstructural stability. Full article

Cylindrical LiFePO₄ batteries are increasingly used in 3C consumer electronics, including computers, communication devices, and consumer electronic products, owing to their favorable safety characteristics, structural robustness, and stable electrochemical performance. Nevertheless, these batteries may inevitably experience mechanical deformation during manufacturing, transportation, assembly, accidental dropping, collision, or vibration, which can compromise their structural integrity and trigger coupled electrochemical degradation. In this study, the structural-damage-induced failure behavior of cylindrical LiFePO₄ batteries for 3C consumer electronics was systematically investigated at 25 °C under different states of charge. By integrating mechanical response, in situ open-circuit voltage, surface temperature, and electrochemical impedance spectroscopy, the evolution of electro-mechanical failure during external loading was quantitatively characterized. The results reveal a pronounced State-of-Charge (SOC) dependent failure mechanism: the initial yield load increases with increasing state of charge, indicating improved resistance to mechanical deformation, whereas electrical failure occurs earlier at higher states of charge, accompanied by abrupt voltage collapse, abnormal voltage rebound, and unstable voltage oscillations. This phenomenon demonstrates a clear decoupling between mechanical strength and electrochemical stability under structural damage, suggesting that a higher state of charge enhances the apparent load-bearing capability while simultaneously aggravating internal electrical instability. These findings indicate that mechanical deformation thresholds alone are insufficient for evaluating the safety of LiFePO₄ batteries used in 3C consumer electronics, and that state of charge, voltage evolution, thermal response, and impedance variation should be jointly considered. This work provides mechanistic insight and experimental guidance for safety assessment, structural protection, and damage-tolerant design of LiFePO₄ batteries in portable electronic devices and other 3C consumer electronics applications. Full article

Background: Current ablation strategies for the treatment of cardiac arrhythmias remain suboptimal. Treating cardiac arrhythmias using epicardial pulsed field ablation (PFA) selectively targets ganglionated plexi (GPs) within epicardial fat, offering a promising alternative to thermal ablation. Previous computational studies lacked physiological realism, excluding catheter geometry, fluid flow and post-PFA thermal latency. This study aimed to develop a realistic 3D epicardial PFA model integrating a clinical catheter, clinical PFA parameters and a sequentially coupled electro-thermal-fluid dynamics model, including thermal latency, to assess electrical and thermal collateral effects near stented coronary arteries. Methods: The model included epicardial fat, myocardium, blood, and the left circumflex artery containing a metallic stent positioned 0.25 mm beneath the catheter electrodes. Pulses of 1000, 2000, and 2500 V (60 pulses × 100 µs, 1 Hz) were simulated to analyze electric field distribution, PFA-induced lesion volume, temperature evolution, and Arrhenius-based thermal damage, including a 90 s post-pulse period to account for thermal latency. The PFA-threshold of 1000 V/cm was considered. Results: The artery reduced PFA-induced lesion size mainly by occupying fat tissue volume, while the stent shielded the lumen without altering fat lesion volume. The presence of a stent produced localized electric field enhancement at the arterial wall, with up to 3.83% of the arterial wall volume affected by PFA in the worst-case configuration. At clinical settings (1000 V), temperature remained below 40 °C and no collateral damage occurred. Voltages > 2000 V increased arterial wall heating, with thermal damage expanding up to five-fold during latency in the epicardial fat. Myocardium remained unaffected in all cases. Conclusions: The computational model developed in this study indicates that clinically relevant PFA parameters (1000 V) produce localized electric field enhancement at the stent–artery interface, resulting in limited collateral electrical effects in the arterial wall, while avoiding collateral thermal effects and preserving the myocardium. However, the use of higher pulse voltages can lead to delayed thermal damage within the epicardial fat. Full article

The failures of semiconductor lasers are often linked to the emergence or growth of defects. However, most research mainly focuses on the postmortem failure analysis caused by defects, lacking dynamic process analysis of defect expansion. This limitation hinders the understanding of defect growth patterns and expansion. In this work, we establish a macroscopic phenomenological model based on the dynamic characteristics of defects in semiconductor lasers. The expansion of defects is regarded as the diffusion transfer process of lattice strain, and the diffusion-limited aggregation (DLA) model is used to describe the aggregation process of random morphology of defects. The effect of model parameters on the growth pattern is studied, and the phenomenological relation between model parameters and actual defect features is established. The model successfully replicated experimentally observed morphologies in a distributed feedback (DFB) laser under high-temperature and high-current excitation. It not only predicts the intermediate process of defect expansion but also reveals the accelerated process. This research provides a novel approach to describing the defect evolution process in semiconductor lasers, contributing to a deeper understanding of defect expansion modes and characteristics within semiconductor lasers. It holds significant guiding implications for improving device reliability. Full article

Overheating of polymeric cable materials is a major contributor to insulation aging, electrical failure, and fire risk in power systems, particularly in densely installed urban underground cable corridors where heat dissipation is limited and early-stage defects are difficult to identify. Although gas-detection approaches are promising for non-invasive overheating monitoring, their practical value depends on identifying material- and lay-er-specific volatile products and clarifying how their release evolves with temperature and time. Herein, volatile products released from the PVC outer jacket of a YJV22-8.7/15 kV-3 × 185 medium-voltage cable were investigated using headspace gas chromatography–mass spectrometry (GC-MS). Temperature- and time-dependent evolution was estimated for selected marker species, and the associated degradation behavior was correlated with chemical/structural and electrical changes using ATR-FTIR, KPFM, and dielectric measurements. The number and observed headspace levels of organic components increased substantially with severe overheating, reaching more than 20 dominant components at 200 °C. 2-Ethylhexanol (2-EH) was observed across the studied range and reached approximately 300 × 10⁻⁶ (volume fraction) at 200 °C for 60 min while remaining at or below approximately 50 × 10⁻⁶ at temperatures up to 140 °C. Benzene was observed mainly at severe overheating, whereas DOTP was first observed at 140 °C among the tested conditions, reaching approximately 40 × 10⁻⁶ at 140 °C for 5 min and exceeding 300 × 10⁻⁶ under more severe conditions. KPFM showed surface roughness increasing from 7.70 to 43.39 nm, and the real permittivity increased by up to 13.9% at 50 Hz. These results provide a temperature- and time-resolved headspace dataset for the tested cable outer jacket and relate its organic-gas profile to surface and dielectric changes. Full article

Grain-oriented silicon steel is a key soft magnetic material for transformer cores, and femtosecond laser scribing provides a potential approach for achieving high-precision magnetic-domain refinement while reducing thermal damage. However, the near-surface electronic response and charge-imbalance behavior of grain-oriented silicon steel during femtosecond laser irradiation are still not well understood. In this study, a two-temperature model coupled with an electron transport model was employed to investigate the evolution of electron temperature and net charge density under different laser fluences and pulse durations. The results showed that laser fluence and pulse duration jointly affected the near-surface electron-temperature response, electron-emission process, and net charge-density evolution in grain-oriented silicon steel. Increasing laser fluence enhanced electron excitation and the degree of charge-distribution imbalance. Meanwhile, increasing pulse duration promoted the extension of the net charge distribution along the depth direction, which indicated that there was a pulse-duration range that can simultaneously promote charge accumulation at the surface and in the near-surface region. These results provided comprehensive insight into the near-surface charge-imbalance behavior during femtosecond laser etching of grain-oriented silicon steel. Full article

Metal additive manufacturing (MAM) is extensively being utilized by aerospace and automobile industries to produce parts with complex geometries with minimum lead time, no material wastage, and higher dimensional accuracy. Additively manufactured (AMed) AlSi10Mg alloys are one of the most used alloys in lightweight structural applications due to their tailored microstructure and suitable mechanical properties for these applications. This review critically presents the recent and current developments on the AlSi10Mg alloys fabricated using various MAM methods such as laser powder bed fusion (LPBF), directed energy deposition (DED), and electron beam melting (EBM). Special attention is given to the establishment of linkage among the process–structure–property–performance of the AMed AlSi10Mg alloy. This review highlights that LPBF-fabricated AlSi10Mg alloys typically exhibit a finer cellular α-Al matrix with a continuous Si network and provide superior strength with lower ductility. DED samples showed a coarser dendritic microstructure and exhibited moderate strength and ductility. However, EBM fabrication leads to near-equilibrium microstructures and exhibits reduced strength with improved ductility due to higher processing temperatures and thermal gradients. The effects of MAM methods, build orientations, and their process parameters on the microstructural evolution and mechanical performance of AlSi10Mg alloy products are extensively investigated. The influence of post-processing methods is also discussed, which reveals their critical role in the anisotropy, ability to mitigate defects like porosity and a lack of fusion, surface irregularities and material strengths. Despite showing steady progress in this area, several challenges like residual stresses, process-induced porosity, and limited availability of universal standardizations remain unaddressed. Such issues raise doubts about the reproducibility and adoption of the fabricated components on a large scale. This review study is likely to help the aerospace and automobile industries in the printing of structural components using an optimized parameter range, leading to an optimized microstructure and balanced mechanical properties with minimum defects. This review provides a comprehensive comparison of the LPBF, DED, and EBM processing routes for AlSi10Mg alloys by correlating the processing parameters to the microstructural evolution, mechanical properties, and fatigue performance. It indicates that the optimization of process parameters and post-processing treatments are the key strategies to reduce defects, control the microstructure, and obtain a good balance between strength and ductility. The review also points out the existing research gaps and future directions towards reliable industrial implementation of AMed AlSi10Mg components. Full article

Pump start-up and shutdown, flow-rate adjustment, and tripping operations during drilling can induce bottomhole pressure fluctuations. These fluctuations may alter fracture aperture and change the development of lost-circulation pathways. To investigate the dynamic evolution of fracture aperture under fluctuating pressure, a thermo-hydro-mechanical (THM) coupled numerical model was established using ABAQUS. Bottomhole pressure fluctuations were induced by applying periodic perturbations to the inlet flow rate. The effects of fluctuation amplitude, fluctuation duration, and drilling-fluid temperature were then analyzed. The results indicate that fracture aperture exhibits a transient response before reaching a stable state. The fluctuation amplitude has a significant effect on the maximum transient fracture aperture. When the fluctuation amplitude increases to 30%, the maximum fracture aperture increases by 44%. In contrast, the fracture that has already formed may undergo reclosure during the low-pressure stage. The fluctuation duration mainly affects the persistence of the fracture opening and reclosure process, but has a relatively weak effect on the maximum fracture aperture. A decrease in drilling-fluid temperature promotes fracture opening and tip propagation. When the formation temperature is 100 °C, low-temperature drilling fluid increases the maximum fracture aperture by 3.06% and the fracture length by 13.89% compared with the isothermal reference case. These findings indicate that fracture aperture under fluctuating pressure cannot be characterized only by its stabilized value. The maximum transient fracture aperture, minimum fracture aperture, and temperature-induced changes in fracture morphology should also be considered. This study provides a numerical insight into the transient response of fracture aperture to bottomhole pressure fluctuations and drilling-fluid temperature during drilling in stress-sensitive fractured formations. Full article

Polylactic acid (PLA) remains poorly mineralized under mesophilic conditions relevant to home and decentralized composting. This study assessed whether bioaugmentation with Amycolatopsis orientalis, protein-based biostimulation with skimmed milk powder, or their combined application could enhance the mineralization of compression-molded amorphous PLA fragments at 28 °C in activated vermiculite. Closed respirometric bioreactors were monitored for 90 days, and the PLA mineralization extent was calculated from the cumulative CO₂ evolution after correction using treatment-specific blanks. The recovered PLA fragments were further analyzed by FTIR-ATR and DSC to provide complementary physicochemical monitoring. The final mineralization remained low, reaching 1.19 ± 1.88% for bioaugmentation, 3.49 ± 1.82% for biostimulation, and 8.75 ± 4.31% for the combined treatment. The combined treatment gave the highest mean value, which was significantly higher than bioaugmentation alone, but the individual biological replicates followed heterogeneous trajectories. In particular, BABS-3 reached 13.19% mineralization, indicating that higher responses can occur at the individual bioreactor level, although they were not consistently reproduced. FTIR-ATR and DSC revealed treatment- and replicate-dependent physicochemical changes but did not provide evidence of extensive bulk PLA transformation. These results contrast those of previous reports of higher PLA mineralization under warmer, mature compost conditions, emphasizing the complexity of the combined influence of temperature and matrix. Overall, the tested strategies were insufficient to achieve effective home compostability of PLA at 28 °C. Full article

Sea surface temperature (SST) anomalies represent a critical threat to the operational safety and productivity of marine ranching systems. Taking a typical marine ranching area in the Northern Yellow Sea as the study area, this study developed a lightweight two-stage field-to-site forecasting framework. In the first stage, a Convolutional Long Short-Term Memory network (ConvLSTM) was employed to generate 1–5 days regional SST forecasts. Through experiments involving 24 input configurations, the combination of Optimum Interpolation Sea Surface Temperature (OISST), seasonal and trend components, and ERA5 meteorological variables was identified as an optimal configuration, providing spatial-evolution constraints for the target location. In the second stage, the 5-day target-site forecasts were concatenated with OISST to construct a 60-day sequence, which was then used to drive a lightweight Gated Recurrent Unit (GRU) for extended forecasts from days 6 to 15. This strategy reformulates the forecasting task into a spatially constrained 10-day extension forecast, thereby suppressing long-lead error accumulation. The results showed that, in the regional forecasting stage, an RMSE of 0.83 °C and MAE of 0.63 °C were achieved on Day 5, while in the extended-forecasting stage, an RMSE of 0.89 °C and MAE of 0.69 °C were achieved on Day 15. Compared with single-stage ConvLSTM and GRU models performing direct 15-day forecasting, the field-to-site strategy reduced RMSE by approximately 25.21% and 9.18%, respectively, and reduced MAE by approximately 24.18% and 8.00%, respectively. Independent validation against in situ buoy observations further showed that the proposed framework introduced only limited additional errors comparable to the inherent discrepancy between OISST and buoy observations. Additional tests under representative marine heatwave (MHW) conditions showed that the framework retained useful forecasting skill under anomalous warming conditions. Furthermore, its extended application experiments at five additional marine ranching sites in the Northern Yellow Sea produced consistent forecasting performance, with mean RMSE and MAE ranging from 0.71 °C to 0.75 °C and from 0.53 °C to 0.56 °C, respectively. The proposed method can therefore provide a risk-warning window of at least two weeks for marine ranching management and support timely operational decisions for temperature-related risk mitigation and refined aquaculture management. Full article

Inorganic thermal-insulation mortars can effectively reduce the energy consumption and carbon emissions of both existing and new buildings while maintaining the thermal stability of building envelopes. Compared with conventional mortars, these materials exhibit more pronounced multiscale coupling during curing, and their microstructural evolution and macroscopic properties are highly sensitive to environmental variables, particularly temperature, humidity, and ionic concentration. This review systematically summarizes the effects of high-temperature curing, high-humidity curing, artificially introduced ions, and special curing regimes on the mechanical properties, durability, thermal conductivity, and fire resistance of inorganic thermal-insulation mortars. The reviewed studies indicate that hydration, geopolymerization, and CO₂-curing reactions can all promote microstructural densification and thus enhance mechanical performance and durability. Elevated temperature and humidity generally accelerate reaction kinetics, intensify internal hydration, and facilitate the generation and deposition of gel products, thereby refining the pore structure and improving strength development. However, the same densification process may also increase the continuity of the solid phase and form more effective heat-transfer pathways, which is unfavorable for thermal-insulation performance. Mildly alkaline curing environments can further stimulate binder reactions and improve matrix compactness, although excessive ionic activity may negatively affect pore stability and long-term performance. Among the coupled curing conditions, wet–dry cycling appears to provide a more favorable balance between mechanical-property development and pore-structure preservation, because periodic humidity gradients can enhance strength formation, stabilize the interfacial transition zone, and reduce cracking sensitivity. Overall, the effect of curing on inorganic thermal-insulation mortars is governed by the competition and balance between reaction enhancement, pore-structure evolution, and interfacial stabilization. Future curing design should therefore focus on system-dependent optimization to achieve a rational balance among mechanical performance, thermal insulation, and fire resistance. Full article

Oxidative degradation stands as the principal cause of gear oil failure and transmission system malfunctions in wind turbines. Electrochemical impedance spectroscopy (EIS) offers a novel technical avenue for the condition monitoring of gear oil. This research centers on the evolution mechanism of electrochemical properties during the oxidative degradation process, utilizing high-viscosity gear oil commonly employed in wind turbines as the research subject. Through a combination of accelerated oxidation tests, broadband EIS measurements, and equivalent circuit fitting, the study examines the variations in the electrochemical response of gear oil with respect to oxidation temperature and duration. The findings reveal that oxidative degradation does not modify the single-relaxation dielectric characteristics of the gear oil; however, various electrochemical parameters undergo systematic evolution. Following oxidation at temperatures ranging from 90 to 120 °C, the charge transfer resistance escalates by approximately 5.9-fold; the base resistance diminishes by 10% to 20%; both the admittance constant and dispersion index of the constant phase element (CPE) exhibit changes of less than 5%, indicating that the system retains its capacitive properties. During constant-temperature oxidation at 90 °C for durations spanning 50 to 175 h, the charge transfer resistance increases in an approximately linear fashion with oxidation time, while the base resistance continues to decline, and the CPE parameters remain largely stable. Various electrochemical parameters evolve monotonically with the extent of oxidation, with charge transfer resistance demonstrating the highest sensitivity to thermal oxidation and thus serving as a pivotal indicator for evaluating the degree of thermal oxidative degradation in gear oil. This study lays an experimental foundation for the application of EIS technology in the realm of online gear oil monitoring. Full article

The firing of traditional gray pottery relies on complex physicochemical reactions governing its color, dimensional accuracy, and structural stability. Unclear kiln-transformation mechanisms restrict standardized and digital production of this Chinese intangible cultural heritage. Herein, direct ink writing (DIW) was used to fabricate Hejin gray pottery green bodies from local ternary raw materials. Thermodynamic calculations, TG–DTG/DSC, XRD, XRF, and atmosphere-controlled firing tests were combined to reveal coupled phase evolution and reduction color-forming mechanisms during sintering. Two interrelated kiln-transformation processes were identified. First, sequential mineral reconstruction occurs at four critical temperatures: free water loss at 119.8 °C, two-stage dehydroxylation of hydrous silicates at 270.5 °C and 767.9 °C, and CaCO₃ decomposition at 547.9 °C. Uneven shrinkage and gas release at these temperatures induce cracking, blistering, and deformation of printed bodies. Micron-sized CaCO₃ (equivalent radius ≈ 1.31 μm) exhibits high surface energy and significantly reduces its decomposition temperature, consistent with experimental observations. Second, reducing atmospheres trigger competitive phase formation. Distinct from the conventional Fe₂O₃ → Fe₃O₄ → FeO reduction pathway, Fe oxides preferentially react with abundant Al₂O₃ to form thermodynamically stable FeAl₂O₄ spinel, yielding uniform celadon-gray tones. The final color is nearly independent of 20–90 vol% CO, and air-isolated cooling below 600 °C is mandatory to prevent secondary oxidation and reddening. This work establishes a thermodynamic framework for DIW-printed Hejin gray pottery kiln transformation, clarifies microscale defect and color-evolution mechanisms, and offers theoretical guidance for atmosphere-controlled firing and digital mass production of heritage ceramics. Full article

Vacuum induction melting (VIM) of recycled powder with bulk master alloy represents an industrialized approach for recycling metallic waste. However, the intrinsic mechanisms governing the co-melting behavior of materials with distinct melting characteristics, such as powder bed and bulk alloy, remain insufficiently understood. To address this, a coupled multiphysics model was developed to simulate the evolution of induction melting involving homogeneous alloys with different morphologies. This model integrates magnetic, electric, and phase-field dynamics while incorporating melt convective heat transfer, thereby establishing a fully coupled electromagnetic-thermo-hydrodynamic framework. Through this modeling approach, the entire VIM process of melting homogeneous alloy with different morphologies can be comprehensively analyzed. The validity of the model was verified via small-scale VIM experiments using FGH96 powder/bulk composite, supported by infrared temperature measurements. This simulation methodology is not only applicable to small-scale recycling but can also be extended to large-scale industrial production, providing a reliable theoretical foundation for the recycling of powder materials. Full article