Search Results (16,001)

The field study was conducted between 2016 and 2018 by the Department of Agronomy at Poznań University of Life Sciences. The experiment took place at the fields of the Research and Education Centre in Gorzyń, Złotniki branch. It was a single-factor trial involving six different sowing dates of an ultra-early maize cultivar: A1—12 April, A2—26 April, A3—10 May, A4—24 May, A5—7 June, and A6—21 June. The cultivar ‘Pyroxenia’ was used in the study. It is characterized by very early maturity (FAO 130), rapid early growth, and intensive stem elongation. In the present study, the optimal sowing time for the maize variety ‘Pyroxenia’ was late April (A2) and early May (A3). Later sowing of this variety resulted in a reduction in fresh and dry matter yields, as well as a reduction in the quality of the feed. The difference between the first (A1) and the last sowing date (A6) resulted in a 47% reduction in fresh weight and a 49% reduction in dry weight yield. No effect of sowing date was observed on starch content or structural carbohydrates, including crude fiber and its fractions (NDF, ADF, and ADL), in maize forage intended for ensiling. Data analysis for the years 2016–2018 showed that air temperature and precipitation had a significant effect on fresh and dry straw weight yields. Partial factor productivity of nitrogen (PFPF_N) decreased with delayed sowing of maize. On average, this parameter for maize sown in June compared with April, was lower by 38.8% for straw dry yield, 54.5% for ear dry yield, and 46.3% for whole-plant dry yield. Full article

In hybrid wire arc additive manufacturing with interlayer friction stir processing (UAMFSP), refined microstructures are produced in aluminum alloy builds; however, the thermal parameters governing layer-resolved defect evolution remain poorly understood. In this study, a correlative mechanistic framework is presented in which post-peak cooling rate is identified as a plausible controlling factor for porosity evolution in UAMFSP Al 4043 three-layer walls. A multi-scale characterization is performed by employing infrared thermography, quantitative optical grain morphology analysis (N  =  10,346 grains, Layers 1–3), scanning electron microscopy from 250× to 35,000×, and image-based porosity quantification from calibrated SEM fields. This primary quantitative comparison is established between L1 and L3 only; Layer 2 is excluded from the 250× quantitative analysis owing to its thermally distinct cooling regime and is treated separately. A counterintuitive layer-dependent porosity gradient is reported, wherein the upper layer (L3) exhibited 80% higher porosity (2.90 ± 1.18%) and 107% higher pore density (4283  ±  900 pores/mm²) than the bottom layer (L1), despite recording a 26% lower peak FSP surface temperature (195.1 vs. 263.2 °C) (n = three fields per layer; Cohen’s d ≈ 1.7). Based on these results, the post-peak cooling rate, rather than peak temperature, is identified as a plausible controlling factor for void consolidation quality, as evidenced by the observation that L3 cools at −12.3 °C/s versus −16.2 °C/s for L1, which is consistent with prolonged high-temperature dwell and reduced plastic-flow-assisted pore closure in the upper layer. The anomalously rapid cooling of L2 (−46.9 °C/s), attributed to a bilateral thermal gradient between the substrate and the air-cooled free surface, places it in a thermally distinct regime; accordingly, L2 is utilized exclusively for high-magnification SEM characterization in this study. High-magnification SEM imaging (12,000×–35,000×) revealed a frequent spatial co-location of sub-micron pores with fragmented Al–Si eutectic particles, which is consistent with preferential void persistence near particle–matrix interfaces. Grain morphology also exhibits non-monotonic evolution with build height, with mean circularity following the order L3 (0.645) > L1 (0.621) > L2 (0.569), and the equiaxed grain fraction ranging from 25.5% (L2) to 36.1% (L3) (ANOVA: F = 56.2, p = 5.15 × 10⁻²⁵), while the mean equivalent grain diameter remained below 3.4 μm across all layers. Overall, the outcomes of this study establish post-peak cooling rate, rather than peak temperature, as a plausible controlling factor for void consolidation quality in UAMFSP builds, with the caveat that complete causal isolation requires controlled single-variable experiments. These outcomes are presented as a first mechanistic framework for this class of hybrid process and are intended to motivate targeted controlled experiments, subsurface thermal characterization, and expanded porosity sampling in future investigations of multi-layer additive–deformation manufacturing of Al-based alloys. Full article

Hydrogen supplementation in compression-ignition diesel engines is increasingly investigated as a practical retrofit approach for reducing the environmental impact of existing marine and stationary diesel power systems. This study examines the effects of hydrogen enrichment on combustion stability, pressure behavior, harmonic response, fuel consumption, and exhaust emissions in a 1966 Deutz A12L 714 marine auxiliary generator-set. The engine was operated at 900, 1200, and 1500 rpm with hydrogen supplied through the intake-air stream at flow rates up to 130.15 L/min. Results indicate that hydrogen enrichment improved fuel consumption and combustion-related dynamic behavior without increasing peak cylinder pressure or exhaust-gas temperature. Low-order vibration harmonics, particularly the 1X and 3X components associated with torque ripple and cyclic combustion variability, decreased with hydrogen addition. COV(Pmax) remained below 0.27% across all operating conditions, indicating preserved combustion stability, while hydrocarbon emissions and fuel consumption decreased by approximately 30% and 13%, respectively, at the highest hydrogen enrichment conditions. Phase-averaged pressure traces obtained showed virtually unchanged combustion-cycle structure and periodicity under maximum hydrogen enrichment. The findings indicate that hydrogen enrichment improves combustion stability and overall engine performance without increasing combustion severity, supporting its potential application as a retrofit solution for marine auxiliary engines, distributed generators, and other legacy diesel-engine systems. Full article

Passive daytime radiative cooling (PDRC) materials require high solar reflectance and high atmospheric window emissivity. However, high solar reflectance achieved by scattering strategies often relies on porous structures, which can compromise the material’s mechanical reliability. To address this trade-off, we develop a layered alumina nanofiber membrane (LANM) by dual-nozzle electrospinning with programmed alternating deposition, in which alternating deposition and subsequent removal of alumina precursor layers and sacrificial polyvinyl alcohol (PVA) interlayers generate a continuously layered architecture with periodic interfaces and interlayer air gaps. This interfacial geometric design enables simultaneous regulation of solar-band scattering and bending load transfer within a single alumina system. Because photon flux attenuates with depth, shallow interfaces contribute more strongly than deeper ones; therefore, the micro-layered architecture enhances scattering while maintaining high emissivity in the atmospheric window. In outdoor testing, LANM achieved a maximum sub-ambient temperature reduction of ~5.8 °C, representing a further improvement of about 2.4 °C compared to Monolithic alumina nanofiber (ANM). Moreover, interlayer interfaces induce a multiple-neutral-axis mechanism and segmented stress transfer, thereby improving bending deformability rather than load-bearing strength. Full article

The carried-out microfield model research was aimed at identifying patterns in the dynamics of soil CO₂ effluxes depending on the locally occurring hydrothermal regimes of regenerated lawn ecosystems on peat–sand substrates with different peat contents. Monitoring was carried out every ten days from 21 April 2019 to 30 October 2019 and included measurements of soil and air temperature, soil moisture, and CO₂ efflux every 3 h during the day. The weather conditions of the 2019 growing season in Moscow, with air temperature close to the annual average and increased precipitation, made it possible to clarify quantitative patterns of the temperature influence on CO₂ efflux from lawn soils in case of their pronounced dynamics without real soil moisture deficit. To study relationships between CO₂ efflux and soil and air temperatures, three empirical CO₂ efflux models (Exponential, Raich–Hashimoto and Lloyd–Taylor) were used with comparative assessment of their results. The conducted investigation showed that both peat content, local hydrothermal regime, and type of vegetation cover play a significant role in efflux modulation, with the temperature factor dominating on both seasonal (72% impact) and intraday (51–94% impact) scales. The lawn substrate factor accounts for up to 10% of CO₂ efflux variability on the intraday scale. The lawn vegetation cover (with the lower and higher diversity) significantly affects the soil hydrothermal regime depending on the peat content (a higher impact with a lower peat content due to the soil pH difference). The denser vegetation reduces the soil temperature, providing better protection, and at the same time reduces soil moisture by transpiration, which provides the combined effect on the CO₂ efflux reduction (up to 1 g CO₂ m⁻² day⁻¹ reduction for the lower-pH soils). Full article

Single-phase oil immersion is a promising alternative to air cooling for high-power servers, but the high viscosity of dielectric fluids amplifies the bypass flow around the CPU heat sink via the adjacent random-access memory (RAM) channels, degrading thermal performance. A simplified hydraulic-thermal analysis shows that this bypass penalty cannot be eliminated by reducing the fin pitch of a rectangular-fin heat sink alone. A staggered pin-fin heat sink is therefore proposed, with pin diameter D, longitudinal pitch S_d, and transverse pitch S_t optimized by three-dimensional CFD using PAO-6. The optimum geometry is D = 2.8 mm, S_t = 6 mm, S_d = 8.45 mm. The heat sink is fabricated and tested in a commercial server at oil inlet temperatures of 30–45 °C and flow rates of 3–6 LPM. At 3 LPM, the pin-fin immersion server reduces the CPU thermal resistance by 22.29% relative to a rectangular-fin immersion server using the same oil, and by 38.37% relative to an air-cooled server. The partial Power Usage Effectiveness (pPUE) reaches 1.015, an 88.09% improvement over the air-cooled baseline (pPUE = 1.126), confirming that pin-fin geometries effectively mitigate the bypass penalty in single-phase oil immersion cooling. Full article

The intensification of the urban heat island effect poses a critical threat to the preservation and habitability of compact historic districts. The Alameda de Hércules in Seville exemplifies this vulnerability, where the intersection of heritage protection and extreme Mediterranean summers limits conventional climate adaptation. This study conducts a multi-temporal evaluation of the square’s climate resilience, spanning from its configuration prior to major 21st-century renovations to its current state and future projections, proposing future interventions. By integrating advanced microclimatic simulation and high-fidelity energy modeling, the research assesses a dual-function strategy: the improvement of the thermal environment while implementing non-intrusive photovoltaic pavements (PVPs) for energy generation. Environmental parameters, including air temperature, mean radiant temperature (MRT), and the universal thermal climate index (UTCI), were analyzed alongside the renewable energy potential of the site’s mobility infrastructure. Four heritage-sensitive interventions were tested: PV-integrated bicycle lanes, shading canopies, reflective pavement, and permeable paved grass. The results demonstrate that the canopies and paved grass zones can lower surface temperature up to 3.7–4.3 °C, reduce UTCI stress up to 2.3–3.0 °C, and decline MRT up to 10.6 °C. These values correspond to the maximum reductions achieved in specific zones. However, the PVP can locally increase surface temperature by about 4.7 °C and the reflective pavements increase MRT by around 10.4 °C, while generating an estimated annual energy yield of 174.19 MWh. The analysis under future climate projections suggests that these strategies remain equally effective under future scenarios. These findings confirm that PV-integrated urban surfaces offer a viable, reversible, and replicable approach to retrofitting historic public spaces, harmonizing climate-adaptive cooling with decentralized energy production without compromising the site’s cultural significance. Full article

Desertification is a serious environmental challenge in regions with desert landscapes, such as the Khorezm Oasis in the Republic of Uzbekistan. Low precipitation rates and shortages of irrigation water have driven dynamic changes in desert-related land use and land cover (LULC) classes, threatening environmental and food security. This study aims to assess desertification safety levels in the Khorezm oasis using geospatial technologies to better understand spatiotemporal dynamics and to support sustainable agricultural management. A multi-criteria decision-making (MCDM) approach was used for desertification assessment. Annual mean values of key indicators—land surface temperature, vegetation index, groundwater (GW) depth, wind speed, soil erodibility (K-factor), precipitation, normalized enhanced sand index, maximum air temperature, and LULC classes—were analyzed for the period 2000–2023. The results indicate that the normalized enhanced sand index and LULC classes exert the strongest influence on desertification processes. Areas classified as high to very high desertification hazard are predominantly concentrated in the Republic of Karakalpakstan, covering a total area of 2345.65 km². Ongoing water shortages in the Amu Darya River basin pose a significant risk of further expansion of desertified areas. The findings provide valuable insights for regional land management and desertification mitigation planning. Full article

Thermal energy storage (TES) is essential for improving the flexibility and efficiency of renewable and industrial energy systems. This study experimentally compares sensible and latent heat storage using basalt aggregate and an encapsulated phase change material (PCM), specifically 60 wt.% NaNO₃–40 wt.% KNO₃, as packed-bed materials under elevated-temperature operating conditions. Tests were conducted in an air-based TES rig at air flow rates of 60–120 kg/h, with packed bed temperatures exceeding 400 °C. Key parameters included temperature profiles, thermal power, energy storage, and recovery during charging and discharging phases. The results indicate that increasing the air flow rate accelerated thermal front propagation and improved charging and discharging power, but did not proportionally increase stored or recovered energy. The basalt bed achieved recovered volumetric energy densities of 108–160 MJ/m³ at about 150 °C and 351–405 MJ/m³ above 320 °C. The encapsulated solar salt bed reached higher values, from 412–508 MJ/m³ near 290 °C to 523–626 MJ/m³ at higher temperatures. Both materials showed high TES efficiencies, in the range of 80–94%. Encapsulated PCM significantly increased energy storage density in packed-bed TES systems, while basalt aggregate provides higher short-term thermal power output. Full article

As climate change intensifies heat extremes, the Urban Heat Island (UHI) effect amplifies local thermal stress. Assessing the UHI using robust observational data, whether ground- and/or satellite-based, is essential for climate risk assessment and evidence-based urban adaptation. Therefore, this study aims to provide a comprehensive climatological assessment of air temperature patterns and UHI intensity across the Lisbon Metropolitan Area (LMA) over a 26-year period (2000–2025). The methodology employs a dense, high-quality integrated network of in-situ weather stations from the Portuguese Institute for Sea and Atmosphere (IPMA) and the National Water Resources Information System (SNIRH). To bridge critical gaps in traditional climate assessments, this research implements a dual-perspective approach that combines the high temporal resolution of MSG-SEVIRI and the spatial precision of MODIS Land Surface Temperature (LST). This framework accurately captures the lag effects between surface heating and atmospheric response. Validation results demonstrate that satellite-derived LST is a robust proxy for monitoring the nocturnal UHI, with differences generally below 1 °C compared with near-surface air temperature observations (T2m). However, daytime LST significantly overestimates atmospheric temperatures, with deviations of 2–8 °C due to solar radiation and urban geometry. The selection of rural reference stations constitutes a critical methodological factor, as a baseline shift can alter perceived UHI intensities by more than 3 °C. Despite these sensitivities, the results unequivocally confirm a persistent and spatially heterogeneous UHI effect in Lisbon, which intensifies during extreme heat events by up to an additional 4 °C. Analysis of the 2003 and 2018 heatwaves reveals surface LST anomalies exceeding 10 °C and urban–rural thermal differentials reaching up to 7 °C under conditions of suppressed maritime breezes. These nocturnal anomalies are particularly pronounced in densely built-up areas, limiting thermal dissipation and preventing physiological recovery. Integrating multi-sensor satellite data with in-situ validation provides a new benchmark for climate risk assessments, delivering the reliable, reproducible data required to strengthen long-term urban resilience under increasingly frequent extreme heat events. Full article

Despite the widespread use of planar flow casting (PFC) for amorphous alloy ribbons, previous two-dimensional (2D) numerical studies have primarily focused on isolated flow or thermal behaviors, lacking a systematic quantification of how key casting parameters collectively influence melt puddle geometry and ribbon thickness. To fill this gap, this work establishes a coupled air–melt two-phase 2D Volume of Fluid (VOF) model based on the continuity, momentum, and energy equations. An analysis was conducted on how various parameters affect the melt puddle behavior and ribbon thickness. The results indicate that, as the roller speed (U) increases from 21 m/s to 30 m/s, the detachment length (Ln) decreases by 31%. Over the same interval, the puddle length (L) decreases by 30%. When the ejection speed (V) increases from 1.4 m/s to 2.0 m/s, the ejection temperature ($T_e$) increases from 1433 K to 1733 K, and the slit width (W) increases from 0.4 mm to 0.6 mm, Ln rises by roughly 39.7–133%, while L increases by approximately 32.3–112%. To produce thinner amorphous ribbons for loss reduction, high roller speed, low ejection speed, and small nozzle slit are crucial parameters. Full article

Ground-level ozone (O₃) has become a major air pollutant in China following PM_2.5, particularly in the southeastern coastal region, where the frequent interaction of typhoons and the subtropical high complicates pollution control. In this paper, spatial autocorrelation and a multiscale geographically weighted regression (MGWR) model were employed to estimate the spatiotemporal heterogeneity and driving mechanisms of O₃ in the Southeast Coastal urban agglomerations from 2015 to 2024. Temporally, the annual average O₃ concentration exhibited a fluctuating trend of an initial increase, followed by a decrease and a subsequent rebound. A bimodal monthly pattern was observed, with peaks in May–June and August–September and minima in winter. Diurnally, the concentration showed a consistent pattern of being higher in the daytime and lower at night, peaking in the afternoon, driven by solar radiation and temperature. Spatially, O₃ exhibited a distinct north–south gradient, with the highest in Jiangsu Province, followed by Shanghai, Zhejiang and Guangdong, and the lowest in Fujian. Significant spatial autocorrelation was detected, with hot spots in the Yangtze River Delta and cold spots in Fujian and adjacent areas. Seasonally, the most severe pollution with the greatest spatial heterogeneity, occurred in summer, contrasting with the uniformly low concentrations in winter. Compared with OLS and GWR, the MGWR demonstrated superior explanatory power. O₃ was jointly influenced by precursors, natural factors, and socioeconomic factors, with the influence intensity ranked as follows: NO₂ > average elevation > population density > annual precipitation> wind speed > built-up area > proportion of the secondary industry in GDP. Notably, the effects of NO₂, annual precipitation, and the proportion of the secondary industry exhibited strong spatial heterogeneity, operating at finer spatial scales. These findings provide scientific support for sustainable air quality management and region-specific O₃ control in southeastern coastal China. Full article

Allergic diseases are increasing globally, particularly among children, who are highly vulnerable due to critical windows of immune development. This review examines climate change as a key environmental determinant driving the rising burden of pediatric allergic diseases, including asthma, allergic rhinitis (AR), atopic dermatitis (AD), and food allergy (FA). Climate change influences disease risk through interconnected pathways, such as increased air pollution, altered aeroallergen patterns, and more frequent extreme weather events. Elevated carbon dioxide (CO₂) levels and rising temperatures prolong pollen seasons and enhance allergenicity, while pollutants such as ozone (O₃) and particulate matter (PM) exacerbate airway inflammation and immune dysregulation. Emerging evidence emphasizes the role of early-life exposure, particularly during prenatal and early postnatal periods, when environmental insults can induce long-term effects via epigenetic modifications and immune reprogramming. These mechanisms may increase susceptibility to allergic sensitization and subsequent disease development. Epidemiological studies consistently link exposure to air pollution, including PM_2.5 (PM with aerodynamic diameter < 2.5 μm) and nitrogen dioxide (NO₂), with increased risk of allergic diseases in children. Additionally, climate change-related events such as wildfires, sand and dust storms, and thunderstorms further elevate exposure to allergens and pollutants, contributing to acute exacerbations and disease progression. Climate change may also contribute to allergic diseases through microbiome dysbiosis, as altered environmental microbial exposures, biodiversity loss, air pollution, and antibiotic-associated microbial disruption may impair immune tolerance and promote allergic sensitization in children. Addressing this growing public health challenge requires integrated mitigation strategies to reduce greenhouse gas (GHG) emissions and improve air quality, alongside adaptive interventions to enhance resilience and reduce exposure. Understanding these mechanisms is essential for developing targeted prevention strategies and protecting child health in a changing climate. Full article

This work evaluates a high-voltage stacked piezoelectric actuator designed for high force and high power, via silicone oil as both the primary dielectric insulator and thermal management medium. The proposed stacked actuator consists of 10 active lead zirconate titanate (PZT) discs, each 2 mm thick and 50 mm in diameter, wired in parallel and mechanically stacked in series. Quasi-static displacement measurements confirm successful operation up to 2.5 kV/mm with a measured free displacement of 25 µm at 5000 V, in agreement with the constitutive displacement relationship, demonstrating that silicone oil provides effective dielectric insulation at the intended field level. Steady-state thermal measurements across drive conditions ranging from 600 V to 1000 V and 2000 Hz to 5000 Hz show consistent surface temperature reductions of 5 °F to 15 °F with the addition of static silicone oil compared to air. Additional results and discussion are disclosed. Full article

With global warming and rapid urbanization, short-duration summer rainstorms are becoming more intense and localized, posing growing challenges to urban flood resilience. However, their spatiotemporal characteristics, vertical structures, and environmental drivers remain poorly understood. Here, we combine multi-source remote sensing datasets and China’s new-generation satellite-borne dual-frequency precipitation radar observations to investigate summer rainstorms in Nanjing, China, during 2017–2024. Results reveal pronounced spatiotemporal heterogeneity, with higher rainfall intensities concentrated over urban and adjacent areas. During the study period, rainstorm intensity and duration increased by 7.44% and 38.63%, respectively, while the affected area decreased by 8.18%, indicating a transition toward more localized yet more intense rainfall events. Environmental analyses suggest that large-scale thermodynamic conditions and regional topographic forcing provide a favorable background for convection development, while local urban thermal effects may further modulate rainfall enhancement. Three-dimensional radar detection of an illustrative rainstorm event indicates an inverted-cone vertical structure, suggesting a mixed convective-stratiform precipitation structure involving both warm-rain and ice-phase processes. An Explainable Bayesian-Optimized XGBoost (EBOX) model further identifies near-surface air temperature and specific humidity as the primary environmental factors associated with rainstorm occurrence and development. Overall, this study highlights the value of integrating satellite remote sensing with explainable artificial intelligence to improve understanding of urban extreme rainfall and provide new insights into how climate change, topography, and urbanization jointly shape precipitation extremes in rapidly urbanizing monsoon regions. Full article