Search Results (3,171)

Urban green infrastructure is increasingly exposed to fine-scale thermal heterogeneity generated by anthropogenic point-source heat emissions, yet the leaf-level responses of adjacent vegetation to such localized stress remain poorly understood. Here, we examined whether air-conditioner (AC) exhaust, a widespread point-source heat emitter, is associated with functional trait shifts in Fraxinus chinensis street trees, and whether easily measurable leaf traits can serve as candidate indicators for ecological monitoring. Using a matched treatment–control field comparison, we compared trees located 2 m from operating AC units with unaffected controls and quantified nine leaf functional traits together with concurrent microclimate variables. AC exhaust created a distinct compound heat–drought–wind micro-environment at the 2 m patch scale, with higher air temperature (+6.3 °C), lower relative humidity (−12.3 percentage points), and higher wind speed (5.2-fold). Exposed trees showed a coordinated shift toward more resource-conservative leaf traits: leaf dry matter content (+14.8%), tissue density (+13.6%), leaf thickness (+6.3%), and stomatal density (+11.7%) increased significantly, whereas specific leaf area (−10.6%), leaf area (−12.5%), chlorophyll content index (−4.6%), and stomatal area (−10.4%) decreased significantly. The observed “small-and-numerous” stomatal configuration suggests altered stomatal regulation, although its implications for transpiration-driven cooling require direct physiological validation. Exploratory structural equation modeling suggested associations among AC-exhaust exposure, leaf economic strategy, and stomatal traits; stomatal regulation showed the highest proportion of model-explained variance (R² = 0.598), but this value should not be interpreted as direct evidence of impairment severity or restoration potential. Leaf dry matter content, specific leaf area, and stomatal density emerged as sensitive and practical candidate indicators of AC-exhaust-associated leaf functional shifts. These findings support precautionary management near AC exhaust outlets, while specific planting-distance thresholds and zoning frameworks require future validation through distance-gradient or manipulative experiments. Full article

Ceramic additive manufacturing offers strong potential for fabricating geometrically complex and application-specific components, yet achieving reliable dimensional fidelity remains challenging because dimensional deviation is governed by highly coupled material, process, thermal, and environmental factors. To address this problem, this study proposes an uncertainty-aware computational framework for dimensional error prediction in ceramic 3D printing under variable material and process conditions. The contribution is positioned as a system-level integration of established learning, uncertainty estimation, calibration, and reliability-interpretation components within a ceramic additive manufacturing dimensional-error prediction workflow, rather than as a fundamental methodological breakthrough. The validation is conducted using the publicly available Ceramic 3D Printing Process Control Dataset, a 1000-sample tabular dataset, and the resulting findings are therefore interpreted as dataset-specific computational evidence rather than direct proof of industrial deployment readiness. The methodology begins with a structured data-driven preprocessing pipeline that transforms the Ceramic 3D Printing Process Control Dataset into a multi-condition feature space through data cleaning, one-hot material encoding, min–max normalization, and engineered descriptors capturing extrusion–speed balance, thermal gradients, cooling intensity, deposition density, and material-conditioned interactions. A multi-branch deep computational architecture is then developed to encode material, process, thermal-environmental, and engineered-feature streams separately, followed by adaptive cross-condition fusion to learn nonlinear dependencies across ceramic printing regimes. To improve reliability beyond deterministic regression, the framework jointly models aleatoric and epistemic uncertainty and incorporates calibration refinement to align predictive confidence with observed error behavior, thereby enabling preliminary reliability-oriented interpretation of stable and high-risk operating conditions. Experimental results demonstrate that the full model achieves the best overall within-dataset performance, with a test MAE of 0.0118, RMSE of 0.0172, $R^2=0.999$, MAPE of 1.74%, calibration error of 0.003, PICP of 0.996, reliability score of 0.992, and a stable prediction rate of 98.7%. Although these values indicate strong predictive behavior under the current structured dataset, the exceptionally high $R^2$ should be interpreted cautiously because external experimental validation, larger measured datasets, and cross-machine ceramic printing trials are still required. These findings show that the proposed framework provides an effective system-level computational strategy for dataset-specific reliability-aware dimensional quality prediction in ceramic additive manufacturing and offers a preliminary data-driven foundation for uncertainty-aware intelligent process optimization. Full article

Boron carbide (B₄C) holds significant application potential in the fields of lightweight, high-hardness protective and high-end wear-resistant components due to its low density and exceptional hardness. However, its strong covalent bonding leads to low sintering activity and weak grain-boundary cohesion, resulting in high brittleness and crack sensitivity. These inherent properties make it difficult to achieve simultaneous full densification and toughness enhancement, severely limiting the reliability of B₄C under complex service conditions. Although diamond is an attractive reinforcement because of its high elastic modulus and low coefficient of thermal expansion, the simultaneous realization of densification, graphitization suppression, and fracture-resistance improvement in diamond/B₄C composites remains insufficiently understood. In this study, diamond particles were introduced into the B₄C matrix and consolidated by rapid high-temperature and high-pressure (HTHP) sintering to synergistically promote densification and fracture toughening. The effects of sintering temperature and diamond content on phase evolution, densification, microstructure, and mechanical properties were systematically investigated, and the associated toughening mechanisms were analyzed. The results indicate that the hardness generally increases with rising sintering temperature and diamond content. The primary toughening mechanisms are identified as the pull-out of diamond particles and crack deflection induced by residual stresses generated during the cooling process. Although the composite with 20 wt.% diamond exhibits higher hardness, it also experiences severe macroscopic cracking. The composite with 10 wt.% diamond sintered at 1450 °C under 5.3 GPa for 4 min exhibits the optimal balance of properties, achieving a relative density of 98.85%, a Vickers hardness of 40.72 GPa, and a fracture toughness of 9.20 MPa·m^1/2. This work confirms the effectiveness of combining diamond reinforcement with HTHP sintering in simultaneously achieving densification and toughening of B₄C-based composites, providing a new pathway for developing high-performance lightweight protective ceramics. Full article

Soluble-boron-free designs for water-cooled small modular reactors offer advantages such as reduced corrosion and simplified systems. However, the absence of soluble boron necessitates higher total control rod worth for reactivity control and the shutdown margin, leading to excessive individual control rod worth, which can lead to severe power excursions during a rod ejection accident (REA), potentially threatening the fuel integrity and core-cooling capability. The analysis of a hypothetical REA for an equilibrium core design showed that the fuel rod cladding failed due to the high reactivity worth of the ejected control rod. To enlarge the safety margins of this design under accidental conditions, two strategies were adopted: implementing a hybrid control rod configuration to decrease the local reactivity worth within single fuel assembly and re-arranging the refuelling loading pattern to prevent fresh fuel clustering. Using an in-house CoreOptimizer tool, the CASMO5 and SIMULATE5 simulations were automatized to find out an optimized equilibrium core design. The results demonstrated that all safety parameters of the optimized equilibrium core designs are within regulatory limits during normal operation and under REA conditions. By reducing the individual control rod worth, power spikes are considerably mitigated, thereby ensuring fuel integrity during an REA. Full article

The slag from electric arc furnace (EAF) steelmaking has potential for various applications, but its safe use requires the assessment of heavy metals, such as chromium leaching, to meet environmental standards. This study investigates the microstructure of EAF slag cooled in a slag pot and its effect on Cr immobilization. Slag samples were collected at full scale using a representative sampling method, dividing the slag pot into six zones (internal and external, top to bottom). Microstructural analysis was performed using scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction, followed by leaching tests on the milled samples. Thermodynamic calculations were performed using FactSage 8.4 to evaluate phase stability and composition. The results indicate that cooling conditions inferred from slag-pot location, spinel size, and spinel zoning are correlated with variations in Cr leaching under neutral conditions. Slower cooling is associated with the formation of large, reverse-zoned spinel phases that may contribute to Cr stabilization, whereas rapid cooling is associated with smaller, homogeneous spinel phases that may increase leaching risk. These findings provide insights for the environmentally safe utilization of EAF slags and inform strategies to minimize Cr release during slag valorization. Full article

Precision glass molding is an economical and resource-efficient method for manufacturing precision optics in a replicative way, offering advantages over conventional manufacturing methods, particularly for complex geometries. However, challenges arise due to different thermal expansion coefficients between the mold and the glass, which lead to shape deviations during the cooling process and require high compensation efforts. This study investigates the machining behavior during ultra-precision grinding of an innovative MAX phase composite whose coefficient of thermal expansion can be specifically adapted to that of glass. The aim is to evaluate the influences of varying process parameters and material configurations on surface integrity and the suitability of ultra-precision grinding for mold manufacturing in the context of precision glass molding. Systematic grinding tests were carried out and complemented by force measurements. The resulting surfaces were characterized using optical measurement technology and atomic force microscopy; in addition, the edge zone was analyzed using transmission electron microscopy. The results confirm the basic suitability of ultra-precision grinding for the MAX phase composite but point to potential subsurface damage that could limit its usability in precision glass molding. Full article

Urban areas increasingly face summer overheating, highlighting the need for passive cooling strategies. Extensive green roofs offer cooling potential, but the individual roles of vegetation and irrigation remain insufficiently quantified. This study addresses this gap through a controlled field experiment using a 2 × 2 factorial design combining vegetated and non-vegetated surfaces with irrigated and non-irrigated conditions. Surface and waterproofing membrane temperatures were monitored during dry conditions and a three-day irrigation period and compared with a meteorologically similar reference day. A factor-based decomposition approach was applied to quantify the contributions of vegetation, irrigation, and their interaction. Results show that vegetation alone provides limited cooling under dry conditions, while irrigation acts as the dominant cooling factor by increasing substrate moisture and thermal capacity. The combined application achieved the most effective performance, reducing the 90th-percentile waterproofing membrane temperature (T_M,90) by 8.51 °C relative to the non-vegetated, non-irrigated reference configuration. The proposed framework supports performance-based design of green roofs under summer heat stress. Full article

Earth-based materials are promising candidates for balancing thermal performance, hygrothermal regulation, and environmental sustainability. The objective of this study is to evaluate and compare the hygrothermal behavior of two earthen materials, structural cob and lightweight insulating earth, against conventional reference concrete, taking into account not only their insulating properties but also their ability to regulate coupled heat and moisture transfers. Experimental tests show a significantly higher hygroscopic buffering capacity for earth-based materials, with an MBV of 2.23 g/(m²∙%RH) for the structural material and 1.21 g/(m²∙%RH) for the insulation material, compared to less than 0.5 g/(m²∙%RH) for concrete. The sorption isotherms confirm distinct water storage behaviors, with an average sensitivity to relative humidity of 10.47% for the insulation material, compared to 3.8% for concrete and 2.25% for the structural material, in addition to an average reduction of 26% in the adsorption capacity between 23 °C and 45 °C for both earthen materials. Coupled heat–moisture simulations in COMSOL quantitatively demonstrate the hygrothermal superiority of bio-based materials over conventional concrete, as concrete promotes interstitial moisture accumulation due to its low vapor permeability. The parametric sensitivity analysis highlights the effect of hygrothermal properties, where diffusivity controls transport kinetics and sorption governs water storage, while thermal conductivity modulates the spatial redistribution of thermo-hygric fields. The next and final step made it possible to link the phenomena observed at the material scale to the actual energy performance of the building, confirming the potential of the double-wall cob + lightweight earth system to reduce heating and cooling requirements and maintain stable indoor comfort, where the annual heating demand is reduced by approximately 24% compared to the conventional prototype. Full article

The northward shift in climate zones and the urban heat island effect demand passive cooling for building roofs in northern regions. Artificial turf is a lightweight candidate, but existing studies treat it as homogeneous material, overlooking blade morphology and roof-scale thermal performance. This study conducted a scaled indoor experiment using a 1 m³ building model. Three artificial turfs with different blade lengths (Type A long, Type B medium, Type C short) were compared against concrete and XPS roofs under simulated summer solar radiation. Results show that blade morphology governs thermal performance. Type A exhibited the lowest peak surface temperature (48.9 °C vs. 53.4 °C and 60.6 °C), and its interface temperature (37.0 °C) was 15.1–19.0 °C lower than Types B and C, attributed to a static air insulation layer and enhanced convection. Its cooling rate (0.98 °C/min) was 1.69–2.33 times faster. Compared to concrete and XPS, Type A had lower surface temperature, less downward heat conduction, and a 29.3 °C drop in 30 min (concrete: 22.3 °C; XPS: 21.7 °C), showing urban heat island mitigation potential. Its heat flux reduction ratio reached 42.9%, with equivalent thermal resistance of ~0.40 m²·K/W, reducing summer peak indoor temperature by 3–6 °C in aging buildings. Double-layer stacking underperformed a single long-blade layer due to heat accumulation. Optimised long-blade turf challenges the view that low albedo inevitably causes high temperature, offering dual benefits of insulation and rapid dissipation for passive cooling in urban renewal. Full article

This study investigates the temperature-dependence performance of high-power lithium iron phosphate (LFP) cells for automotive starter batteries. Temperature effects on high-power LFP cells are contextualised based on pertinent literature in order to compare the typical capacity behaviour of lead–acid batteries with LFP. Experiments were conducted on five cylindrical LFP cell types in a thermal chamber across ambient temperatures from +45 °C to −30 °C using a 9 C discharge regime aligned with automotive standards. Electrical and thermal behaviours were analysed, including energy yield, power output, and surface temperature monitored by sensors and thermal imaging for room temperature. Energy output decreased exponentially with temperature but remained above 70% for most LFP cells at −18 °C, while only one cell type was functional at −30 °C. Thermal analysis at ambient temperature confirmed homogeneous temperature distribution without hotspots and low overall heating (from 2 °C to 14 °C), indicating no need for additional cooling for starter battery applications. A conservative power analysis indicated that 4 kW at −30 °C would require a 28P4S 26650 configuration, representing a lower-bound estimate. We argue that even this conservative figure suggests a potential for weight reduction compared with lead–acid systems. Energy-based Pb-equivalence factors of approximately 1.2 at −18 °C and 3 at −30 °C were derived. A preliminary guideline for cell dimensioning based on measurements at 25 °C is proposed to address discrepancies between data sheet specifications and actual performance for pack configuration based on required power. Full article

The economic viability of second-generation (2G) bioethanol production depends on the availability of robust, multistress-tolerant yeast strains capable of withstanding harsh industrial conditions. This study investigates animal manure as a novel ecological niche for discovering such strains, as microbes in these environments naturally adapt to high organic loading and fluctuating temperatures. From eighty-six initial isolates, twenty-nine demonstrated superior xylose fermentation at 37 °C. Eight high-performing isolates (C2-1, B1-2, B1-6, B2-6, B2-8, G1-4, G1-5, and G2-4) exhibited exceptional tolerance to ethanol, high temperatures, and lignocellulosic-derived inhibitors (acetic acid, formic acid, furfural, and vanillic acid). Molecular identification classified isolate C2-1 as Pichia kudriavzevii and the remaining seven as Candida tropicalis. In synthetic media, C. tropicalis B2-8 produced up to 16.33 g/L of ethanol using xylose (60 g/L) as the sole carbon source. While the undetoxified, highly acidic sugarcane bagasse hydrolysate completely inhibited yeast growth, the industrial potential of these strains was successfully validated using the concentrated, undetoxified enzymatic hydrolysate derived from the acid-pretreated sugarcane bagasse solids, which contained 30.15 g/L glucose and 25.58 g/L xylose. P. kudriavzevii C2-1 achieved ethanol titers of 6.02 g/L and 5.71 g/L at 37 °C and 40 °C, respectively. The C. tropicalis strains outperformed P. kudriavzevii, yielding 6.12–6.35 g/L at 37 °C and maintaining 5.75–6.19 g/L at 40 °C. These findings underscore the potential of manure-derived yeasts as resilient biocatalysts. Although their fermentation yields remain relatively low and require further metabolic optimization, their ability to survive and ferment in this concentrated, undetoxified enzymatic hydrolysate at elevated temperatures makes them promising candidates for further development in high-temperature ethanol fermentation (HTEF), offering a potential pathway toward reducing cooling costs associated with 2G biorefineries. Full article

This study analyzes surface air temperature (SAT) trends at 158 stations located on or above the Arctic Circle over the 2000–2024 period, aiming to assess whether recent temperature shifts could serve as indirect indicators of a slowing Atlantic Meridional Overturning Circulation (AMOC). Regression analysis reveals that only 40% of stations show statistically significant warming trends (p < 0.05), while 33% exhibit no significant trend. Applying the Pettitt and Buishand tests, we detect abrupt regime shifts at 38 stations, with breakpoints concentrated between 2009 and 2014. Notably, 36 of these stations display a weakening of the warming trend after the breakpoint: at 13 stations (including key Arctic archipelagos and the White Sea coast), an initial increase shifts to a decrease; at 17 stations, warming continues but at a slower rate; and at 6 stations (near the Bering Strait), a decrease intensifies. These spatial patterns suggest a potential fingerprint of AMOC slowdown, consistent with recent modeling studies that predict cooling in northwestern Europe and possible Little Ice Age-type environmental conditions. Our findings have implications for assessing future Arctic navigation, coastal infrastructure, and resource extraction under changing climate regimes. Full article

Rising demand for high-performance battery thermal management systems (BTMSs) has rendered single-mode cooling insufficient for advanced lithium-ion batteries (LIBs) in new energy vehicles (NEVs), particularly under high discharge rates. This study proposes a synergistic hybrid BTMS integrating composite phase-change material (CPCM)–aluminum foam with liquid cooling to enhance thermal regulation of cylindrical battery modules under 5 C discharge conditions. Multiple liquid-cooled plate (LCP) configurations, including serpentine, straight, and leaf-shaped designs, together with different flow channel topologies (FCTs), were systematically investigated and optimized. The effects of coolant flow speed (CFS) and ambient temperature were also analyzed. Results indicate that the optimized leaf-shaped LCP with FCT #2 delivers superior performance, limiting the maximum temperature to 309.98 K, reducing temperature difference by 7.6%, and decreasing pressure drop by 88.79% compared to the serpentine configuration. Increasing CFS improves heat dissipation and delays PCM melting, although it raises pressure losses. Furthermore, the proposed system maintains a cell-to-cell temperature difference below 0.51 K, indicating excellent thermal uniformity. Compared to a CPCM-only system, the hybrid BTMS reduces peak temperature by 8.81 K under elevated ambient conditions (309.15 K), demonstrating strong potential for reliable and efficient thermal management in demanding operating environments. Full article

Molecular dynamics simulations were conducted to investigate the thermal stability and structural evolution of Li-Mg alloys subjected to thermal cycling between 100 K and 400 K. Alloy compositions containing 0, 5, 10, and 20 at.% Mg were analyzed using a modified embedded-atom method interatomic potential. Structural characterization was performed through radial distribution functions, Polyhedral Template Matching (PTM), and mean squared displacement (MSD) calculations. The results showed that heating promoted the temporary formation of HCP, FCC, and other local atomic environments, indicating partial loss of crystalline ordering even below the melting temperature of Li. Nevertheless, the BCC structure remained dominant for all compositions, and the structural changes were reversible during cooling. Increasing Mg concentration improved the thermal stability of the alloys by reducing the formation of non-BCC atomic structures and decreasing atomic mobility during thermal cycling. In particular, the 20 at.% Mg alloy preserved more than 90% of the BCC population throughout the simulations. In addition, the energy variations between cycles remained very small, indicating stable thermodynamic behavior during heating and cooling. These findings provide atomistic insight into the temperature-dependent behavior of Li-Mg alloys that may be useful in works related to lithium-metal battery applications. Full article

This paper investigates the potential of localized air-curtain microclimate control to reduce HVAC energy consumption in electric vehicles while maintaining occupant thermal comfort. The study compares conventional full-cabin cooling with driver-focused and passenger-focused air-curtain configurations under controlled ambient conditions of 32 °C. The experimental framework combines analytical airflow and heat-transfer modeling with comparative HVAC performance evaluation using power consumption, time to reach thermal comfort, and Predicted Mean Vote (PMV) analysis. The results show that the air-curtain configurations reduce HVAC power consumption from 3.2 kW for conventional cooling to 2.3 kW and 2.5 kW for the driver- and passenger-focused configurations, corresponding to energy savings of approximately 22–28%. In addition, localized airflow significantly accelerates thermal comfort attainment, reducing stabilization time from 8 min to 4–5 min while maintaining PMV values within acceptable comfort limits. The findings demonstrate that occupant-centered air-curtain microclimate strategies can improve HVAC energy efficiency, reduce auxiliary energy demand, and support more sustainable and range-efficient operation of next-generation electric vehicles. Full article