Search Results (435)

Forest ecological connectedness is defined as the spatial continuity of forested patches and landscapes that facilitate the exchange of materials, biodiversity, and ecosystem services; it has become an important criterion for environmental quality and economic productivity in China. Although forest cover in China has been rapidly increasing since the 1990s, forest ecosystems remain fragmented across administrative regions, resulting in complex environmental effects. This study develops a robust provincial-level Forest Ecological Connectivity Index (FECI) by merging forest cover, fragmentation, functional corridor density, and carbon stock data for 30 Chinese provinces (excluding Tibet, Hong Kong, Macao, and Taiwan) between 2013 and 2023, using data from national forest inventory records, satellite-based forest-cover products, and published databases. We use panel data econometrics (fixed-effects models, spatial Durbin models (SDMs), mediation analysis) to analyze the effects of within-province FECI improvements and ecological spillovers across provinces on (i) air quality (PM_2.5 concentrations), (ii) hydrological regulation (annual surface runoff variability), (iii) regional GDP growth and green total factor productivity (GTFP), and (iv) carbon sequestration in neighboring provinces. Results indicate that a one-standard-deviation increase in FECI is associated with a 4.7 μg/m³ reduction in PM_2.5 in the same province (p < 0.01) and an 23.4% reduction in annual runoff variability (relative to sample mean) in the same province (p < 0.05), with a statistically significant positive impact within a spatial bandwidth of 300–500 km. Provinces with higher forest connectivity have lower per-unit-GDP carbon emissions and higher GTFP growth (β = 0.18, p < 0.01). Mediation analysis shows that forest connectivity’s overall economic impacts are driven by ecosystem services, with carbon sequestration and water-yield regulation as the main ones, accounting for about 42%. These empirical, data-driven insights are expected to strengthen spatial governance and carbon-neutrality policy frameworks in China by incorporating ecological connectivity planning. Full article

Indoor air temperature influences heat exchange between sleeping infants and indoor environments, yet its effects on convective and radiative dry heat transfer in ordinary ventilated rooms remain unclear. Using a previously validated three-dimensional CFD model of a realistic 9-month-old nude infant thermal manikin, this study simulated body-surface heat transfer at 18, 21, 23, 25, and 28 °C. A low-Re k-epsilon turbulence model was coupled with a surface-to-surface radiation model to calculate convective and radiative heat fluxes and heat transfer coefficients. Results showed that chamber airflow displaced the infant thermal plume toward the feet, exposing the head to cooler air and creating warmer microclimates around the lower limbs. At 18 °C, whole-body convective and radiative heat fluxes were 76.65 and 68.16 W/m², respectively; each 1 °C temperature increase reduced them by 5.24 and 3.74 W/m². Convection dominated at ≤21 °C, while radiation became dominant above 23 °C. The head showed the greatest temperature sensitivity, with convective and radiative heat fluxes decreasing by 61.08 and 41.66 W/m² from 18 to 28 °C. Empirical equations based on skin-to-environment temperature differences fitted most heat transfer coefficients well (R² > 0.93), providing boundary condition data for infant thermoregulation modeling and room thermal control. Full article

Coastal polynyas in the Kara–Laptev Seas regulate winter air–sea exchange and sea-ice production, but neighboring polynya systems can behave differently. This study examines January–April variability of the Ob–Yenisey (OY), western Laptev Sea (WLS), and eastern Laptev Sea (ELS) polynyas from 2003 to 2025 using passive-microwave sea-ice concentration, ERA5 winds and air temperature, AMSR-MPR sea-surface temperature, TOPAZ4b sea-ice thickness, and AO/ENSO indices. The three regions show distinct spatiotemporal variations. The OY exhibits the only significant increase in accumulated polynya area (+1.72 × 10⁴ km² day a⁻¹), the WLS has the largest interannual variability and the most frequent large-area events, and the ELS is most strongly concentrated in late March and April. NW has the clearest same-day or one-day-lead association with opening, consistent with wind-driven mechanical divergence, while coastline orientation and landfast-ice geometry are associated with differences in regional responses. Hierarchical partitioning (HP) assigns the largest daily relative statistical allocation to SST in the WLS and ELS; because this association is predominantly synchronous, it is interpreted as an ice–ocean state relationship rather than as a demonstrated antecedent control. Annual associations are more region dependent and include NW, T2M, SST, and SIT. AO is positively correlated with polynya activity, whereas ENSO has no consistent relationship. Full article

The intensification of poultry production, associated with climate change, has increased the occurrence of heat stress, compromising animal welfare and productive efficiency. Despite recent advances, studies quantifying heat exchange in quail under different environmental and dietary conditions from an integrated bioenergetic perspective remain scarce, particularly regarding the shift between sensible and latent heat dissipation mechanisms. In this context, this study aimed to quantify and model sensible and latent heat exchange, together with associated physiological responses, in Japanese quail (Coturnix coturnix japonica) subjected to different air temperatures and dietary inclusion levels of the macroalga Gracilaria birdiae. A total of 864 quail were distributed in a completely randomized design, arranged in a 4 × 3 factorial design with four macroalgae inclusion levels (0.00, 3.00, 6.00, and 9.00%) and three air temperature levels (25.00, 29.00, and 33.00 °C), and maintained in climate-controlled chambers. Heat exchange was estimated using biophysical models integrating convective, radiative, and evaporative heat fluxes. Increasing air temperature reduced sensible heat exchange and intensified latent heat losses (p < 0.0001). During the growing phase, approximately 73.18% of sensible heat exchange was dissipated through radiation. In the laying phase, reductions of up to 59.96% in sensible heat exchange were observed, along with increases exceeding 50.00% in latent heat losses and reductions of up to 26.00% in total heat exchange. Increasing air temperature promoted higher respiratory rate (p < 0.0001), whereas surface and cloacal temperatures remained within the physiological range required to maintain homeothermy. Dietary inclusion of up to 9.00% G. birdiae exerted only limited effects on the quantified heat exchange pathways and did not impair physiological thermoregulation under the experimental conditions evaluated. No significant interaction between air temperature and dietary supplementation was observed for the heat exchange variables (p > 0.05). These findings show that heat stress was the primary determinant of bioenergetic heat exchange, whereas dietary supplementation with G. birdiae exerted only limited effects. Full article

Waterlogging restricts root-zone oxygen availability and can impair seedling growth and leaf quality in mulberry. Root-zone aeration may reduce waterlogging injury, but its effects on root anaerobic metabolism, photosynthesis, oxidative stress, and leaf functional quality have not been well integrated. In this study, Morus alba L. ‘Longsang No. 1’ seedlings were subjected to four treatments: normal moisture without aeration (CK), normal moisture with intermittent root-zone aeration (RA), waterlogging without aeration (WL), and waterlogging with intermittent root-zone aeration (WL+RA). Waterlogging was maintained with a water layer 1–2 cm above the substrate surface, and root-zone aeration was supplied using an air pump and microporous aeration stones for 30 min every 4 h. Root-zone dissolved oxygen, growth traits, root activity, root fermentative indicators, root and leaf oxidative injury, gas exchange, chlorophyll fluorescence, antioxidant enzyme activities, and leaf quality-related traits were measured after 14 d of treatment. Waterlogging decreased root-zone dissolved oxygen from 6.62 to 1.69 mg L⁻¹. It also reduced plant height, total leaf area, shoot and root dry weight, root activity, Pn, Fv/Fm, Y(II), and ETR. In contrast, WL increased ADH and PDC activities, lactate and ethanol contents, MDA, H₂O₂, electrolyte leakage, and NPQ. Leaf 1-DNJ, polysaccharides, total phenolics, total flavonoids, DPPH, ABTS, and FRAP were also reduced under WL. Intermittent aeration increased root-zone dissolved oxygen to 4.64 mg L⁻¹ under waterlogging and partially alleviated many of these changes. WL+RA showed higher growth, root activity, photosynthetic performance, PSII photochemical efficiency, antioxidant enzyme activities, and leaf functional quality than WL. These results indicate that intermittent root-zone aeration was associated with better mulberry seedling performance under waterlogging, together with changes in root-zone oxygen status, fermentation metabolism, photosynthesis, oxidative balance, and leaf quality. Full article

Optical microfibers are fabricated by pulling classical silica fibers until reaching diameters of a few micrometers or less. These devices are significantly exploited in many science and engineering fields, ranging from fundamental research to practical applications. Despite their many attractive advantages, a major technological challenge remains: heating caused by laser absorption from surface defects and contaminants. In the present study, we propose, for the first time to our knowledge, a novel method to measure the temperature evolution of laser self-heated microfibers in air at a wavelength of 1.48 µm. This method, simple and fast, enables us to investigate the influence of the diameters and lengths of the microfibers. We found that the temperature of the microfibers increases linearly with the power and measured a rise of 70 °C for a 1 µm diameter and 20 mm length microfiber at a moderate power of 160 mW. A numerical model considering the microscale and the heat exchange with air is proposed and is adjusted with experimental data, providing values for the thermal transfer coefficient. By investigating power scaling, this work enables the prediction of temperature increases in self-heated microfibers in air, paving the way for new insights into the self-cleaning of microfiber-based devices and for optimized control of light propagation at high power levels. Full article

The evaluation of heat transfer in a back-pass channel for an industrial circulating fluidized bed (CFB) reactor was studied. The authors proposed a heat transfer model taking into account (i) convective heat transfer on the tube side, (ii) convective heat transfer on the shell side, and (iii) radiative heat transfer on the shell side. The analysis of heat transfer is based on measured data from tubular heat exchangers (superheater SH Ia, reheaters RH Ia and RH Ib, and economizer ECO). Performance tests were conducted over a wide range of CFB reactor loads (from 40% MCR to 100% MCR) and also at a secondary air-to-primary air ratio of 0.11. The experimental data as a function of flue gas temperature, maximum flue gas velocity, CO₂ partial pressure, fly ash concentration, and particle size are discussed. During performance tests, the temperature and velocity of flue gas are no more than 1206 K and 16.3 m/s, respectively. As the CFB reactor load decreases from 100% MCR to 40% MCR, the overall heat transfer coefficient of tubular heat exchangers decreases from 60.61 W/(m² × K) to 30.1 W/(m² × K). The overall heat transfer coefficient was higher when the fly ash concentration was higher (from 0.0412 kg/m³ to 0.0612 kg/m³) in the back-pass channel of the CFB reactor. Mean particle size of fly ash corresponds to the maximum overall heat transfer coefficient at bigger (d₅₀ = 0.038 mm) and smaller (d₅₀ = 0.015 mm) particle diameters. Achieved heat transfer findings were calculated at carbon dioxide partial pressure varied between 8.48 kPa and 11.53 kPa. Research studies conducted on an industrial CFB reactor showed that the thermodynamic parameters of steam also influenced heat transfer. The geometry of the heat exchange surfaces affected heat transfer augmentation in the back-pass channel of the CFB reactor. For practicality, the relationships between the heat transfer data and other operational parameters are proposed using regression analysis. Comparing the operational data and the model results, the average absolute error is 19.23%. The heat transfer findings may be used in data-driven design, scale-up, commissioning, and operation of commercial CFB reactors. Full article

Concentration polarization is a common phenomenon in membrane separation processes and generally impairs mass transfer efficiency. Electrodialysis (ED) is considered a promising technology for concentrating high-salinity solutions used in air-conditioning systems; however, concentration polarization under high-concentration operating conditions remains insufficiently understood. In this study, a numerical framework combining a simplified model and a coupled transport model was developed to characterize concentration distributions within an ED concentrate channel. The effects of flow velocity, current density, and feed concentration on concentration profiles were systematically investigated. The results show that transmembrane water transport plays an important role in concentration polarization, and neglecting this effect leads to significant overestimation of ion concentration near the membrane surface. Although ion concentration increases markedly in the vicinity of the ion-exchange membranes, it remains nearly constant in the bulk region along the flow direction. Based on this non-uniform concentration distribution, a conceptual ED configuration with separated flow channels was proposed and evaluated. The results indicate that selectively extracting the enriched boundary-layer region can enhance the outlet concentration of the product stream, whereas increasing the intermediate channel width reduces volumetric yield, revealing a clear trade-off between concentration enhancement and production capacity. Full article

This study evaluates winter in-car microclimate and aerosol conditions in a Prague Metro line C M1.3 car under real operation. Five Letňany–Háje runs were divided into 19 inter-station segments. TDC, PM₁₀, PM₄, PM_2.5, PM₁, CO₂, air temperature, relative humidity, A-weighted sound pressure level, and occupancy were recorded. Aerosol fractions were measured in separate runs and treated as operational optical estimates, not as reference-equivalent or simultaneous size-distribution data. Temperature, relative humidity, CO₂, sound level, and occupancy were aggregated to one value per run and segment and analyzed by randomized-block ANOVA with run as the block. Significant segment effects were found for occupancy, CO₂, relative humidity, and air temperature; L_A showed no stable segment effect. Central segments showed passenger-related CO₂ and heat accumulation, whereas aerosol maxima did not coincide with maximum occupancy. Larger cut-point PM runs showed greater dispersion and episodic peaks, consistent with surface–tunnel exchange, resuspension, and station/ventilation pathways. Across 19 segment means, occupancy correlated more strongly with CO₂ than with air temperature (r = 0.837 vs. 0.633); after Run adjustment, the slopes were 8.494 ppm/passenger and 0.011 °C/passenger, respectively. An overnight Vltavská–Florenc transect provided qualitative evidence of local ventilation influence near Štvanice. The study is a winter, vehicle-specific segmental case study. Full article

Inadequate ventilation in university dormitories risks microbial exposure, but its association with pathogen prevalence in dust across indoor surfaces remains unclear. In this study, we monitored nocturnal air exchange rates (AERs) over a year in dormitory rooms and collected settled dust samples from beds, desks, and floors across four seasons. Based on the World Health Organization (WHO) priority bacterial and fungal pathogen lists, 34 pathogenic species were initially identified from gene sequencing data. We built multivariate regression models to evaluate the associations of daily cumulative ventilation status before dust sampling with the distribution of these pathogens. The results indicated a low compliance rate (AER ≥ 0.7 h⁻¹, 43.2–52.1%) for ventilation in the dormitories. Fusarium and Acremonium were detected in most samples (92.3–99.5%). The modulatory effect of nighttime cumulative ventilation varied heavily across pathogen species and surface types. The relative abundance of Candida tropicalis on bed dust exhibited a stable negative correlation with long-term cumulative AER (β: −0.42 to −0.50), whereas the relative abundance of Salmonella correlated positively with higher AERs. This study demonstrates that ventilation is not a universal pathogen-control measure, revealing its temporal cumulative characteristics and spatial heterogeneity of ventilation in modulating indoor pathogens, and provides a theoretical foundation for implementing precision ventilation strategies in university dormitory environments. Full article

Forest cover change alters land–atmosphere exchanges of energy, water, and carbon, thereby influencing local and regional climate. This study assessed climatic patterns associated with afforestation in Khyber Pakhtunkhwa, Pakistan, from 2003 to 2023 using remote sensing data and Google Earth Engine. Land surface temperature (LST) was treated as the primary response variable, while evapotranspiration (ET) was analyzed as a secondary response variable. Air temperature; precipitation; vegetation indices, including the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI); and elevation were used as supporting variables to interpret the broader climatic and biophysical responses of afforestation. MODIS land-cover, LST, ET, and vegetation-index products, together with climate research unit (CRU) climate data and ALOS-PALSAR DEM, were used to evaluate spatiotemporal trends and variable relationships. The results showed that mean LST increased by 0.520 ± 0.070 °C across KP during 2003–2023; however, areas classified as forest gain showed a localized cooling pattern of 0.490 ± 0.050 °C during the 2013–2023 forest-cover transition assessment window. Afforested areas also exhibited increased ET, whereas forest-loss areas showed reduced ET and higher LST. Specifically, ET increased by 0.013 ± 0.002 mm/8-day in afforested areas, whereas forest-loss areas showed a decline of 0.005 ± 0.001 mm/8-day. CRU-derived regional air temperature showed an increasing tendency of 0.310 ± 0.050 °C, whereas precipitation showed only a weak and statistically non-significant regional tendency; therefore, precipitation was used only as background climatic context. The NDVI and the EVI were negatively correlated with daytime LST, and elevation showed a strong negative relationship with LST. Overall, the findings indicate that forest-cover gain was associated with localized surface cooling patterns and improved vegetation–climate regulation indicators in the study area. Full article

Buildings account for a substantial share of global energy consumption and greenhouse gas emissions, while a large proportion of the existing building stock remains energy inefficient. Thermal transmittance is a fundamental indicator for assessing the thermal performance of historic building envelopes. This study investigates the application of UAV-based quantitative infrared thermography (UAV-QIRT) for in situ U-value measurement as an alternative to conventional methods. This study proposes a structured workflow for UAV-QIRT-based U-value measurement, developed in accordance with BS EN ISO 6781-1:2023. The study evaluates four U-value calculation formulas using thermographic data acquired during an in situ case study and compares the resulting estimates with a reference U-value obtained using the heat flow meter (HFM) method. The results demonstrate that the reliability of UAV-QIRT-based U-value estimation strongly depends on outdoor thermal boundary conditions and the physical assumptions embedded within the heat balance model. In this case, the measured exterior wall surface temperature was lower than the outdoor air temperature, causing simplified formulas to produce physically unrealistic negative U-values. In contrast, the complete heat balance model, which accounts for radiative exchanges with the sky, surroundings, and ground, as well as convective heat transfer, generated more plausible estimates. Nevertheless, significant discrepancies were observed between the UAV-QIRT and HFM estimates. Sensitivity analysis revealed a high dependence of UAV-QIRT-derived U-values on environmental boundary conditions, including wind speed, outdoor air temperature, and exterior surface temperature. Full article

River water temperature connects hydrodynamic processes, air–water heat exchange, and aquatic ecological responses. Although data-driven models are increasingly used for short-term water-temperature forecasting, input-variable choice still influences both predictive skill and the interpretation of model errors. This study examined daily water-temperature forecasting at nine hydrological stations in the upper and middle reaches of the Yangtze River. The stations were grouped according to natural hydro-meteorological background, reservoir regulation, and compound disturbance. Based on surface-water heat balance and order-of-magnitude analysis, antecedent water temperature, air temperature, and discharge were selected as process-related candidate inputs and tested using LSTM and xLSTM models. The experiments considered input-window length, learning rate, batch size, and the inclusion of discharge. Under the no-discharge scheme, learning rate had the clearest effect on the predicted water-temperature series. For LSTM, the median predicted-temperature differences caused by changes in window length, learning rate, and batch size were 0.055, 0.077, and 0.056 °C, respectively; the corresponding values for xLSTM were 0.089, 0.102, and 0.073 °C. One-day-ahead forecasts for the selected representative dates produced mean RMSE values of 0.160 °C for LSTM and 0.165 °C for xLSTM, compared with 0.183 °C for a persistence baseline. The reservoir regulation impact group showed the lowest errors, whereas the compound disturbance impact group had higher errors and clear within-group differences. The contribution of discharge varied among stations and models: for LSTM, RMSE decreased at Batang, Panzhihua, and Huanglingmiao, but increased or changed little at Gangtuo, Yichang, and Cuntan; for xLSTM, the average RMSE did not decrease after discharge was added at the seven stations with discharge data. xLSTM showed local advantages at Huanglingmiao and Cuntan. These findings show that process-informed input selection offers a consistent basis for comparing multi-site water-temperature forecasts and for interpreting error differences among stations and input schemes. Full article

The Internet of Vehicles (IoV) is reshaping intelligent transportation through pervasive connectivity, real-time data exchange, cooperative perception, and vehicle–edge–cloud services, while also expanding cybersecurity and privacy risks across heterogeneous cyber–physical environments. This paper presents a PRISMA 2020-informed systematic review of IoV security and privacy protection research. A cross-layer and lifecycle-oriented analytical framework is developed by integrating a four-layer IoV architecture—sensing layer, network access layer, coordinative computing layer, and application layer—with a five-stage data lifecycle covering data collection, transmission, storage, usage, and disposal. Based on this framework, the paper examines representative threat surfaces, vehicle-to-everything (V2X) communication security, public key infrastructure (PKI) based authentication, trust management, privacy-preserving data sharing, intrusion detection, active defense, and AI-assisted security analytics. Privacy-preserving mechanisms, including differential privacy, federated learning, blockchain, homomorphic encryption, and secure multi-party computation, are further compared in terms of deployment layer, lifecycle stage, real-time suitability, and representative performance evidence. In addition, the review discusses the engineering relevance of UNECE WP.29 R155/R156, ISO/SAE 21434, and related national standards, with emphasis on compliance evidence, over-the-air (OTA) governance, supply-chain coordination, and lifecycle cybersecurity management. The review shows that no single protection mechanism can simultaneously satisfy the requirements of real-time performance, scalability, privacy preservation, trustworthiness, and regulatory compliance in dynamic IoV environments. Future research should emphasize lightweight and adaptive protection, cross-layer trust coordination, privacy–utility co-optimization, trustworthy AI-assisted security operations, and evidence-based lifecycle governance. This review provides a structured reference for researchers and a practical basis for secure and privacy-aware IoV system design. Full article

In this study, we report the results of the structural characterization and electrochemical evaluation of novel cobalt-free layered Ruddlesden–Popper (RP) oxides, La₂SrFe₂O_7−δ and La₂SrFe_1.8Ga_0.2O_7−δ, as electrode materials for intermediate-temperature solid oxide cells. X-ray diffraction confirmed the formation of RP phases and phase stability after reducing treatment. The materials showed compatible thermal expansion behavior, with slightly lower thermal expansion coefficients for the Ga-doped composition. Oxygen pressure relaxation measurements demonstrated that the oxygen surface exchange coefficient increases with temperature and pO₂, while Ga substitution slightly reduces the O₂/oxide exchange rate, which may be associated with a lower concentration of oxygen vacancies. The electrical conductivity in air was higher for La₂SrFe₂O_7−δ than for the Ga-doped sample, while both compositions showed much lower conductivity under reducing conditions. Symmetrical cell impedance spectroscopy showed high polarization resistance for the electrodes, which was substantially reduced by applying a Ag current collector (0.43 Ω cm² for La₂SrFe₂O_7−δ and 0.73 Ω cm² for La₂SrFe_1.8Ga_0.2O_7−δ at 800 °C), consistent with the limited electronic conductivity of the oxide layers. Overall, both oxides exhibit structural stability, acceptable thermomechanical compatibility, and measurable oxygen exchange activity, making them promising candidates for further development as cobalt-free electrodes in solid oxide cells. Full article