Search Results (64,235)

Ultra-long pool structures used in mine water treatment projects are typical large-volume concrete structures that are highly susceptible to cracking due to the combined effects of cement hydration heat, seasonal temperature variations, and internal water pressure. Such cracking can compromise the durability and long-term service performance of the structure. In this study, distributed fiber optic sensing and finite element analysis were conducted to observe the response of ultra-long pool structures under thermal–load effects. System comparison shows that the average error between the monitored peak thermal strain values and the corresponding simulated values is within 9%. Parametric analysis using the validated simulation model indicates that the hydration protocol with temperatures of 15 °C (casting), 55 °C (peak), and 15 °C (stable), a temperature drop of −20 °C, and loading conditions in sub-pools 3+6 and sub-pools 1+3+5 are the most unfavorable scenarios for inducing tensile stress. When a temperature drop of −20 °C is combined with loading conditions in sub-pools 3+6 or sub-pools 1+3+5, the tensile stress in the pool structure increases by 30% compared to the stress induced by loading alone. This indicates that during the service life of the pool structure, extreme temperature variations combined with mechanical loading may result in localized cracking. This study provides a comprehensive understanding of ultra-long pool behavior during construction and service phases, supporting effective maintenance and long-term durability. Full article

Atmospheric water harvesting, as an emerging water collection technology, is expected to mitigate water resource crises. Adsorption-based atmospheric water harvesting technology offers distinct advantages, including geographical independence and reduced reliance on ambient humidity levels. Herein, a thermoresponsive gel (PNIPAM/TO-CNF) integrated with lithium chloride was constructed to achieve accelerated moisture sorption and rapid desorption capabilities. In the designated PNIPAM/TO-CNF/LiCl gel, PNIPAM provided a temperature-responsive hydrophilic–hydrophobic transition network; the hydrophilicity and structural strength were enhanced by TO-CNF, the moisture absorption capacity was dramatically elevated by hygroscopic salt LiCl, and pore-forming agent polyethylene glycol created a favorable porous structure. This synergistic design endows the gel with an optimized hydrophilic network, temperature-responsive behavior, and a porous architecture conducive to water vapor transportation, thereby achieving rapid moisture absorption and desorption. Under 60% relative humidity, the gel exhibited a water vapor adsorption capacity of 144% within 1 h, reaching its maximum absorption capacity of 178% after 140 min. The gel exhibited an even more superior desorption performance: when heated to 70 °C, its moisture content rapidly decreased to 16% of its initial weight within 1 h, corresponding to the desorption of 91% of the total absorbed water. A simplified pore-forming methodology that enables the integration of temperature-responsive properties with efficient moisture transfer channels was reported in this paper, providing a viable design pathway for achieving accelerated adsorption–desorption cycles in atmospheric water harvesting. Full article

Drought, a complex and frequent natural hazard in the context of global change, poses a major threat to key forest ecosystems in the carbon cycle. However, current research lacks a systematic and quantitative analysis of the multi-factor drivers of drought sensitivity based on lagged and accumulative effects. To address this gap, a drought sensitivity model was established by integrating both lagged and accumulative effects derived from long-term remote sensing datasets. To leverage both predictive power and interpretability, the XGBoost–SHAP framework was employed to model nonlinear associations and identify the threshold effects of driving factors. In addition, the Geodetector model was applied to examine spatially explicit interactions among multiple drivers, thereby uncovering the coupling effects that jointly shape forest drought sensitivity across China. The results reveal the following: (1) Drought had lagged and accumulative effects on 99.52% and 95.55% of forest GPP, with evergreen broadleaf forest showing the strongest effects and deciduous needleleaf forest the weakest. (2) Evergreen needleleaf forests have the highest proportion of extremely high drought sensitivity (16.94%), while deciduous needleleaf forests have the least (1.02%), and the drought sensitivity index declined in 67.12% of forests over decades. (3) Temperature and precipitation are the primary drivers of drought sensitivity, with clear threshold effects. Evergreen forests are mainly driven by climatic factors, while forest age is a key driver in deciduous needleleaf forests. (4) Interactive effects among multiple factors significantly amplify spatial variations in drought sensitivity, with water–heat coupling dominating in evergreen forests and structure–climate interactions prevailing in deciduous forests. Full article

Hybrid thermoelectric generators (HTEGs) play a pivotal role in sustainable energy conversion by harnessing waste heat through the Seebeck effect, contributing to global efforts in energy efficiency and environmental sustainability. In practical sustainable energy systems, HTEG output performance is significantly influenced by uncertainties in the operational parameters (such as temperature differences and load resistance), material properties (including Seebeck coefficient and resistance), and structural configurations (like the number of series/parallel thermoelectric components), which impact both efficiency and system stability. This study employs the Sobol-sequence-sampling method to characterize these parameter uncertainties, analyzing their effects on HTEG output power and conversion efficiency using mean values and standard deviations as evaluation metrics. The results show that higher temperature differences enhance output performance but reduce stability, a larger load resistance decreases performance while improving stability, thermoelectric materials with high Seebeck coefficients and low resistance boost efficiency at the expense of stability, increasing series-connected components elevates performance but reduces stability, parallel configurations enhance power output yet decrease efficiency and stability, and greater contact thermal resistances diminish performance while enhancing system robustness. This research provides theoretical guidance for optimizing HTEGs in sustainable energy applications, enabling the development of more reliable, efficient, and eco-friendly thermoelectric systems that balance performance with environmental resilience for long-term sustainable operation. Full article

Over the last several years, a significant advancement in high-voltage electronic packaging techniques has paved the way for next-generation power electronics. However, controlling the thermal properties of these new packaging solutions is still a major challenge. The utilization of wide bandgap semiconductors such as SiC and GaN offers effective methods to minimize thermal inefficiencies caused by conduction losses through high-frequency switching topologies. Nevertheless, the need for high voltage in electrical systems continues to pose significant barriers, as heat generation remains one of the most significant obstacles to widespread implementation. The trend of electronics design miniaturization has driven the development of high-performance cooling concepts to address the needs of high-power-density systems. As a result, the design of effective cooling systems has emerged as a crucial aspect for successful implementation, requiring seamless integration with electronic packaging to achieve optimal performance. This review article explores various thermal management approaches demonstrated in electronic systems. This paper aims to provide a comprehensive overview of heat transfer enhancement techniques employed in electronics thermal management, focusing on core concepts. The review categorizes these techniques into concepts based on fin design, microchannel cooling, jet impingement, phase change materials, nanofluids, and hybrid designs. Recent advancements in high-power density devices, alongside innovative cooling systems such as phase change materials and nanofluids, demonstrate potential for enhanced heat dissipation in power electronics. Improved designs in finned heat sinks, microchannel cooling, and jet impingement techniques have enabled more efficient thermal management in high-density power electronics. By fixing key insights into one reference, this review serves as a valuable resource for researchers and engineers navigating the complex landscape of high-performance cooling for modern electronic systems. Full article

There is increasing interest in the role of parks as potential cool refuges in the age of climate change. Such potential refuges result from the Park Cool Island (PCI) effect, reflecting the temperature differential between the park and surrounding urban areas. However, this study of different park typologies in Perth, Australia, illustrates that while surface temperatures are 10–15 °C lower in parks during summer afternoons (much less than at other times), air temperatures are generally no different from the adjacent streetscape for the smaller parks. Only the largest park in the study had 1–2 °C lower morning and mid-afternoon air temperature differentials. The study illustrates that while the PCI is a real phenomenon, the magnitude in terms of air temperature is small, and it is of less relevance to the conditions felt by humans in average summer daytime conditions than the direct effects of solar radiation. Many studies have assessed the PCI effect, an indicator that has shown a wide range across different studies and measurement techniques. However, this novel paper utilises satellite remote-sensed land surface temperatures, on-ground measurements of surface temperatures, air temperatures, and humidity, as well as modelling using the microclimatic simulation software ENVI-met version 5.0. A reliance on land surface temperature, which in isolation has a marginal correlation with human experience of thermal comfort, has led some researchers to overstate the PCI effect and its influence on adjoining urban areas. The research reported in this paper illustrates that it is the shade provided by the canopy in parks, rather than parks themselves, that provides meaningful thermal comfort benefits. Accordingly, adaptation to increasing temperatures requires the creation of a continuous canopy, ideally over parks, streetscapes, and private lots in an interconnected network. Full article

Intense thunderstorms known as Nor’westers develop in the Eastern and North Eastern parts of India and Bangladesh before the monsoon season (March to May). The associated severe weather can cause extensive damage to property and livestock. This study uses the pre-monsoon volumetric data of S-band radar from 2013 to 2018 located in Kolkata to investigate the diurnal variation in the characteristics of the storms over Gangetic West Bengal. The cell initiation, echo top heights, maximum reflectivity, and core convective area are determined by using a flexible feature tracking algorithm (PyFLEXTRKR). The variation of the parameters in diurnal scale is examined from 211,503 individual cell tracks. The distribution of the severe weather phenomena based on radar based thresholds in spatial and temporal scale is also determined. The results show that new cell initiation peaks in the late evening and early morning, displaying bimodal variability. Most of these cells have a short lifespan of 0 to 3 h, with fewer than 5 percent of storms lasting beyond 3 h. The occurrence of hail is much greater in the afternoon due to intense surface heating than at other times. In contrast, the occurrence of lightning is higher in the late evening hours when the cell initiation reaches its peak. The convective rains are generally accompanied by lightning, exhibiting a similar diurnal temporal variability but are more widespread. The findings will assist operational weather forecasters in identifying locations that need targeted observation at certain times of the day to enhance the accuracy of severe weather nowcasting. Full article

The growing demand for sustainable and antibiotic-free animal production has intensified interest in probiotics as functional feed additives. In this study, novel strains of Weizmannia coagulans (WC412 and WC413) were isolated from pickle water—a previously unexplored source for probiotic screening. These isolates, along with three reference strains (W. coagulans S8, S15, and S17), were evaluated for their tolerance to heat, acid, and bile salts. Strain WC412 exhibited superior environmental resilience, as validated by principal component analysis (PCA) for comprehensive stress-tolerance assessment, and was selected for further investigations. A murine model was employed to assess the physiological and microbiological impacts of WC412 supplementation at varying doses. Medium-dose (1 × 10⁷ CFU·mL⁻¹) administration significantly improved body weight gain by 13% (p < 0.05), modulated serum lipid profiles, and increased antioxidant enzyme activity and IgG/IL-2 levels (p < 0.05). Notably, WC412 uniquely enriched beneficial genera (e.g., Fructilactobacillus and Limosilactobacillus) and promoted metabolic pathways linked to short-chain fatty acid production, as revealed by 16S rDNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. These findings highlight WC412 as a robust probiotic candidate for enhancing animal growth performance and gut health through novel microbiota-mediated mechanisms. Full article

As urbanization accelerates, a host of negative ecological impacts have become increasingly prominent. Green roofs, as a sustainable solution, can effectively mitigate the urban heat island effect and reduce carbon footprints. However, the lack of datasets on plant species suitable for green roofs in China has hindered the advancement of relevant research and practical applications. Therefore, this study constructed a diversified dataset of plant species for green roofs in China, using data sources from the China National Knowledge Infrastructure (CNKI) and Web of Science (WoS). Generated by integrating the Kimi large language model (Kimi LLM) API with knowledge graph technology, the dataset contains 2248 plant records. It specifically includes a statistical CSV file with detailed plant information, a CSV file of species combinations, a CSV file linking plant combinations to cities, and original plant data extracted from research papers. Technical experiments have validated the accuracy and efficiency of this dataset in acquiring plant species. Suitable for plant selection in green roof projects, this dataset will provide strong support for in-depth research and wider applications in the field of urban sustainability. Full article

The flow and heat transfer in a rotating disk cavity with dual axial inlets are investigated under a range of operating conditions. A full 360° computational fluid dynamics model is employed, with 40 simulation cases varying the rotational Reynolds number (Re_ω= 1.9 × 10⁶–3.1 × 10⁶) and axial throughflow Reynolds number (Re_z = 7.3 × 10⁵–1.2 × 10⁶). The results show that elevated rotation intensifies turbulent mixing and significantly enhances convective cooling on the upstream disk, whereas increasing throughflow improves heat transfer on the downstream disk by promoting deeper coolant penetration. However, an excessive axial flow rate can induce local thermal stratification near the upstream disk, which offsets its heat transfer gains, and strong rotation diminishes the marginal benefits of higher throughflow on downstream cooling. Overall, the study reveals distinct cooling behaviors on the upstream and downstream disk surfaces governed by the interplay between rotation and throughflow. These findings provide insight into optimizing dual-inlet cavity designs and underscore the importance of balancing rotational speed and coolant flow distribution for effective thermal management in gas turbine disk cavities. Full article

Ready-to-eat products are very popular and controversial due to their microbial safety. The main processing steps in obtaining a safe, edible product is heat treatment. The traditional manufacturing of meatballs, which conducts unhealthy compounds related to deep-fat-fried foods like the oil oxidation of harmful substances and polycyclic aromatic hydrocarbons, has been replaced with baking (180 °C) and steaming (94 °C). The addition of aqueous extract from two herbs, lemon balm (Melissa officinalis L.) or wild thyme (Thymus serpyllum L.), has led to twelve variants of meatballs, obtained from the tenderloin of three different animal species (pork, turkey, and beef). During processing, the food components go through conformational changes that affect the texture of the final product. In this study, differential scanning calorimetry for detecting and characterizing the thermal changes in meatballs was used. In addition, the influence of heat treatments on the textural and rheological parameters of meatballs was evaluated using instrumental methods. The cooking yield registered values of 61.21 ± 0.25% for steamed beef samples and 81.36 ± 0.86% for steamed turkey samples. The latest samples also showed the lowest firmness value, 3.41 ± 0.79 N. In this study, the addition of aqueous extracts did not considerably affect the texture and rheological behavior, which were influenced mainly by the heat treatment and meat type. Generally, steaming determined a firmer texture compared to baking. Full article

The article discusses the current challenges facing the energy sector in the context of climate policy, technological transformation, and the urgent need to increase energy efficiency while reducing greenhouse gas emissions. Modern thermal energy conversion technologies are analyzed, including supercritical steam and gas–steam cycles, as well as distributed systems using renewable fuels and microturbines. Particular attention is given to innovative systems with isothermal expansion, which theoretically allow operation close to the efficiency limit defined by the Carnot cycle. The study presents calculation results for conventional systems (steam, gas with regeneration, and Organic Rankine Cycle) and proposes a novel isothermal air turbine cycle. In a combined gas–steam configuration, the proposed cycle achieved an efficiency exceeding 43% at a relatively low heat source temperature of 700 K, clearly outperforming conventional steam and ORC systems under the same thermal conditions. The use of a simple working medium (air), combined with the potential for integration with renewable energy sources, makes this concept a promising and viable alternative to traditional Rankine and Brayton cycles in thermally constrained applications. Full article

Rising global temperatures are increasingly affecting plant performance, leading to reduced growth, altered metabolism, and compromised membrane integrity. Although plant growth-promoting bacteria (PGPB) show promise in enhancing thermotolerance, the underlying mechanisms remain insufficiently explored. Therefore, this study investigated the effects of PGPB inoculation on Zea mays under control (26 °C) and heat stress (36 °C) conditions. Maize plants were inoculated with two thermotolerant bacterial strains and their effects were compared to non-inoculated plants through morphometric, biochemical, and lipidomic analyses. Heat stress negatively affected germination (−35.9%), increased oxidative stress (+46% for LPO, +57% for SOD, +68% for GPx), and altered leaf lipid composition, particularly fatty acids, glycerolipids, and sphingolipids. Inoculation with Pantoea sp. improved germination by 15% for seeds exposed to heat stress, increased growth (+28% shoot and +17% root), enhanced antioxidant defenses (+35% for CAT and +38% for APx), and reduced membrane damage by 65% compared with the control. Lipidomic profiling revealed that inoculation mitigated temperature-induced lipid alterations by reducing triacylglycerol accumulation and preserving the levels of polyunsaturated galactolipids and hexosylceramides. Notably, Pantoea sp.-inoculated plants under heat stress exhibited lipid profiles that were more similar to those of control plants, suggesting enhanced heat resilience. These results underscore the importance of specific plant–microbe interactions in mitigating heat stress and highlight PGPB inoculation as a promising strategy to enhance crop performance and resilience under projected climate warming scenarios. Full article

Urban green spaces (UGSs) are a vital component of urban landscapes nowadays, with an impact on energy distribution in cities and local climate regulation. This study aims to quantify the thermal and optical behavior of various materials in a small-scale Mediterranean UGS and provide insights into the use of green and artificial materials in urban parks. The analysis also includes the changes in the UGS’s optical and thermal properties following its restoration in 2024. The thermal comfort in the UGS is assessed for the 2020–2024 period, along with the reflectivity and surface temperatures of the different materials pre- (in 2022) and post-restoration (in 2024), using in situ measurements. The results show notable seasonal and interannual variability in the thermal comfort of the site. The impact of vegetation on the UGS was critical. The vegetation-covered surfaces exhibited surface temperatures close to ambient air temperature, highlighting their effective thermal regulation. During summer mornings, the average temperatures of the vegetation-covered surfaces were around 30.5 °C, lower compared to artificial or non-green materials, like asphalt, concrete, gravel, and dry bare soil, which were above 42 °C. The vegetation albedo was relatively lower (around 0.19), while artificial covers showed a greater reflectance (up to 0.35), thus boosting the heat retention. These results highlight the essential importance of green infrastructure incorporation to boost the thermal dynamics of urban open spaces and mitigate climate change effects. Full article

The intensification of urban heat in high-density cities has raised growing concerns for public health, infrastructural resilience, and environmental sustainability. As large-scale, multi-functional open spaces, sports stadiums play an underexplored role in shaping urban thermal patterns. This study investigates the spatial and temporal thermal characteristics of eight representative stadiums in central Shanghai and the Pudong New Area from 2018 to 2023. A dual-framework approach is proposed: the Stadium-based Urban Island Regulation (SUIR) model conceptualizes stadiums as active cooling agents across micro to macro spatial scales, while the Multi-source Thermal Cognition System (MTCS) integrates multi-sensor satellite data—Landsat, MODIS, Sentinel-1/2—with anthropogenic and ecological indicators to diagnose surface temperature dynamics. Remote sensing fusion and machine learning analyses reveal clear intra-stadium thermal heterogeneity: track zones consistently recorded the highest land surface temperatures (up to 37.5 °C), while grass fields exhibited strong cooling effects (as low as 29.8 °C). Buffer analysis shows that cooling effects were most pronounced within 300–500 m, varying with local morphology. A spatial diffusion model further demonstrates that stadiums with large, vegetated buffers or proximity to water bodies exert a broader regional cooling influence. Correlation and Random Forest regression analyses identify the building volume (r = 0.81), NDVI (r = −0.53), nighttime light intensity, and traffic density as key thermal drivers. These findings offer new insight into the role of stadiums in urban heat mitigation and provide practical implications for scale-sensitive, climate-adaptive urban planning strategies. Full article