Search Results (4,968)

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

This study investigates the preparation and characterization of tin micro- and nanoparticles with an emphasis on phase-transformation-induced particle formation and chemical purity. Microparticles were generated through repeated phase transformations between β-Sn (white tin) and α-Sn (gray tin), exploiting the associated volumetric changes to induce fragmentation and particle size reduction. The evolution of particle size distribution was systematically analyzed as a function of transformation cycles. The data were analyzed using the modified Johnson–Mehl–Avrami–Kolmogorov equation, and the saturation particle size corresponds to the grain size of the original tin sheet. The phase transformation was induced homogeneously by α-Sn particles and heterogeneously by InSb, and the results were comparable. The influence of the surrounding atmosphere was studied. The increase in oxygen content during repeated phase transformation was measured. In parallel, tin nanoparticles were synthesized via a solution-based route using ammonium hexachlorostannate as a precursor. The nanoparticles precipitated from this solution at mild temperatures during the β-Sn to α-Sn transformation at 13.2 °C. Both micro- and nanoparticles were characterized in terms of morphology and size distribution. The results provide insight into the relationship between phase transformation and particle size reduction mechanisms, and offer a controllable pathway for the preparation of tin particles across micro- and nanoscale regimes. Full article

Cast Al-3Cu-Li alloys are limited by coarse grains and non-uniform Cu-rich phases, but their traverse-speed-dependent response to friction stir processing (FSP) has not been systematically clarified. The effect of FSP traverse speed on the microstructural evolution and mechanical properties of an Al-3Cu-Li alloy was systematically investigated. The alloy was processed at traverse speeds of 20 mm/min and 100 mm/min, and the resulting microstructures were characterized by XRD, SEM, EDS, EBSD and TEM. The results show that FSP does not significantly change the main phase constitution of the alloy, which remains dominated by the α-Al matrix with Al-Cu-related secondary phases. However, FSP markedly modifies the grain structure and precipitate distribution. Compared with the as-cast alloy, both FSP-treated samples exhibit refined equiaxed grains formed through dynamic recrystallization. The FSP-20 sample shows a finer and more homogeneous recrystallized structure, with a mean grain size of 4.60 ± 0.62 μm based on 982 measured grains, whereas the FSP-100 sample exhibits a coarser grain structure with a mean grain size of 15.20 ± 2.17 μm based on 109 measured grains. EBSD analysis further reveals that the FSP-20 sample possesses lower grain orientation spread and more dispersed local misorientation, indicating more sufficient dynamic recrystallization and lower residual deformation. TEM observations confirm the presence of plate-like T₁ precipitates in both FSP samples, while the precipitates in the FSP-100 sample are relatively coarser. Mechanical testing showed that the microhardness, yield strength, ultimate tensile strength and elongation increased from 62.4 HV, 92.8 MPa, 178.5 MPa and 10.86% in the as-cast alloy to 85.5 HV, 170.0 MPa, 228.9 MPa and 20.41% in FSP-20, and to 78.2 HV, 166.8 MPa, 202.9 MPa and 17.63% in FSP-100, respectively. Fracture analysis indicates that FSP-20 is dominated by ductile dimpled fracture, whereas FSP-100 shows more obvious quasi-cleavage features associated with coarse precipitates. Full article

Vegetation recovery after forest fires is a vital indicator of ecosystem resilience. However, the specific differences between structural and functional recovery after fire have remained unclear. In this study, we quantified and compared post-fire recovery using two distinct vegetation indicators: the Enhanced Vegetation Index (EVI) for structural recovery and Solar-Induced Chlorophyll Fluorescence (SIF) for functional recovery. We analyzed the spatiotemporal dynamics and drivers of post-fire recovery. A Transformer model was used to simulate pre- and post-fire variations in EVI and SIF, while a Random Forest model was employed to identify the key drivers of recovery. We analyze the spatiotemporal dynamics and drivers of post-fire recovery. A Transformer model simulates pre- and post-fire variations in EVI and SIF, while a Random Forest model identifies key drivers of recovery. Our results show a steep decline in both indicators after fires, with SIF recovering more slowly than EVI. Three years after the fire, about 78% of burned areas regain at least 80% of their pre-fire EVI levels, but SIF recovery reaches only 70%. Bivariate dependency analysis indicates that precipitation and temperature promote recovery, whereas topography and the Differenced Normalized Burn Ratio (dNBR) have the opposite effect. This study advances a phased, analytical approach to post-fire forest vegetation recovery, offering a dual-perspective framework for understanding forest resilience and providing actionable insights for sustainable restoration and management. Full article

This study presents a meta-analysis of relatively high-resolution paleohydrological proxies derived from geological archives in Sardinia and in the Italian Peninsula–Sicily over the last 2000 years, with particular emphasis on the Medieval Warm Period (MWP) and the Little Ice Age (LIA). The investigated climate proxies, ranging from annual-decadal to centennial resolution, include terrestrial and marine sediment cores, glaciers, pollen spectra, speleothems, lake-level fluctuations, as well as sedimentary and geomorphological inventories. Such datasets were analyzed through holistic and stratigraphic approaches along West–East and North–South transects across the central Mediterranean. Limited temporal resolution and incomplete stratigraphic continuity of several paleoclimatic records from the investigated regions thwart full reconstructions of paleohydrological trends. Nevertheless, the presented meta-analysis has enabled: (1) the recognition of reliable paleoclimatic correlations between the two regions, which exhibit long-lasting anti-phase hydroclimatic trends (wetter conditions in Sardinia and drier conditions in central Italy during the MWP, with the opposite pattern during the LIA); and (2) the identification of the North Atlantic Oscillation (NAO) as the primary driver of these paleohydrological variations. The significance of this anti-phase pattern is discussed in the context of the North–South and West–East climatic dipoles identified in the Mediterranean region during the middle to late Holocene. Furthermore, we assessed the potential of the investigated paleohydrological network to: (1) compare reconstructed hydrological patterns with mean temperature and precipitation records derived from empirical and model-based climate reconstructions in southern Europe and the Mediterranean; and (2) identify gaps in data coverage that currently limit our understanding of high-resolution spatiotemporal hydrological variability and dynamics.The hydroclimatic pattern in Sardinia and in the Italian Peninsula–Sicily has exhibited marked spatio-temporal divergences, with major hydroclimatic transitions coincident with well-known solar minima over the last millennium, thus suggesting a possible cause-and-effect relationship. The interpretations presented in this study provide a framework for understanding how changes in the paleoclimatic variability of water resources may have influenced different regions of Italy since the Middle Ages, potentially affecting societal transitions as well as historical and socioeconomic dynamics. Comparison of the multidecadal-to-centennial reconstructions of paleohydrological patterns is presented for both areas, pending the development of new, higher-resolution, and more precisely dated proxies from the Italian records. Their importance is emphasized in order to improve reconstructions of past climate variability and to enhance assessments of future climate trajectories. Full article

Drought represents one of the major constraints limiting maize productivity in southeastern Europe, particularly under non-irrigated conditions. This study evaluated the effectiveness of foliar biostimulants derived from animal collagen and keratin hydrolysates in mitigating drought stress and improving maize performance in southern Romania during a six-year field experiment (2020–2025). During the screening phase (2020–2022), four formulations (FM1, FM2, KC, and K2) were applied at two rates (5 and 10 L ha⁻¹) and compared with an untreated control. Significant effects of biostimulant formulation and dose were identified for plant height and grain yield (p < 0.001). Duncan’s multiple range test showed that K2 applied at 10 L ha⁻¹ achieved the highest mean grain yield (87.71 q ha⁻¹), significantly exceeding the untreated control (70.94 q ha⁻¹). Based on these results, K2 was selected for long-term validation during 2023–2025 and subsequently evaluated across the entire six-year experimental period. Mean grain yield increased from 52.06 q ha⁻¹ in the untreated control to 58.74 and 64.91 q ha⁻¹ following K2 application at 5 and 10 L ha⁻¹, respectively. Yield improvements were particularly pronounced during years characterized by severe precipitation deficits, when relative yield increases reached up to 41.9%. Economic analysis demonstrated positive net returns in all experimental years, with average profits of 108.6 EUR ha⁻¹ and 206.9 EUR ha⁻¹ for the 5 and 10 L ha⁻¹ application rates, respectively. The results demonstrate that keratin-based biostimulants derived from industrial by-products can improve maize productivity, enhance drought resilience, and contribute to circular-economy approaches in sustainable agriculture. Full article

Supportive therapy with haemoadsorption is gaining popularity in critically ill patients, with the aim of reducing overinflammation triggered by the cytokine storm. The haemoadsorbers used are not specific for cytokines and also bind antibiotics. The aim of this study was to develop and validate a simple analytical method for the simultaneous determination of selected antibiotics and to develop an in vitro model for the quantification of their binding to the CytoSorb^® haemoadsorber under conditions simulating sepsis. Imipenem (IMI), amoxicillin (AMO), cefepime (CEF), meropenem (MERO), vancomycin (VAN) and piperacillin (PIP) were measured in bovine plasma via precipitation with acetonitrile and liquid–liquid extraction with dichloromethane. The aqueous phase was collected and analysed using a C18 HPLC system under gradient conditions, with modulation of organic solvent content and mobile phase pH, and detection performed using a UV/Vis detector. The method was linear (r² > 0.982) across investigated analytical ranges (1.0–100.0 µg/mL for AMO and VAN, 1.0–75.0 µg/mL for CEF, MERO and PIP and 2.5–100.0 µg/mL for IMI). Intra- and inter-day precision did not exceed 14% and accuracy ranged from 85.8% to 108.5%. Using the in vitro model, we showed that CytoSorb^® significantly removed VAN and PIP, but not MERO. Further clinical studies are needed to establish the clinical significance of these findings and their impact on antibiotic exposure. Full article

In the current work, the microstructural characteristics and corrosion performance of an Al-3.6Cu-1.0Li-0.40Mg-0.32Mn-0.12Zr alloy are correlated across different artificial aging regimes (150 °C, 160 °C, and 170 °C). In the under-aging stage, the corrosion depth increases with rising aging temperature, from 342.86 μm at 150 °C to 495.13 μm at 170 °C, indicating deteriorated corrosion resistance at higher temperatures. This trend is closely related to the significant increase in the proportion of the T1 phase in the matrix’s primary precipitate. Upon artificial aging for 24 h, the hardness increases gradually as the aging temperature rises. At higher aging temperatures, short-term aging hardness is higher, likely due to the formation of the T1 phase, which can also provide a strengthening effect. In contrast, the corrosion resistance of the alloy is enhanced at higher aging temperatures after 24 h of aging. These corrosion phenomena are closely related to the dominance of the θ″ phase during low-temperature aging and the gradual increase in the S′ phase during high-temperature aging. Furthermore, a transition from intergranular corrosion to pitting corrosion is identified at the high aging temperature of 170 °C with extended aging time. This corrosion mode transformation behavior is speculated to result from intermittent formation of magnesium segregation near the grain boundary, which alters the electrochemical heterogeneity between grain boundaries and the alloy matrix. Full article

This work systematically investigates the effects of pre-deformation, post-aging temperature, and aging time on the mechanical properties, corrosion behavior, and microstructure of a 2A97 Al-Cu-Li alloy. Microstructural characterization indicates that the main precipitates are T₁ (Al₂CuLi), δ′ (Al₃Li), θ′ (Al₂Cu), and S′ (Al₂CuMg). At 160 °C with 0% pre-deformation strain, increasing aging time increases the size and number density of T₁, changing the size and number density of δ′ and θ′ accordingly, whereas raising the aging temperature to 180 °C mainly coarsens precipitates. Increasing pre-deformation from 0% to 12% increases T₁ number density and refines its size. Significantly, after aging at 180 °C, θ′ is absent in the 8% and 12% pre-deformed alloys, and T₁ re-dissolves in the over-aged 12% alloy. Grain-boundary (GB) phases evolve from fine/discontinuous (under-aged) to fine/continuous (peak-aged) to coarse/discontinuous (over-aged). At the same time, higher pre-strain reduces their size, and higher aging temperature promotes coarsening. Higher aging temperature and pre-deformation accelerate age hardening and shorten the peak-aging time. In the peak-aged state, strength increases but elongation decreases with increasing pre-deformation or aging temperature. Among all, the 4% pre-deformed alloy aged at 160 °C for 30 h shows optimal room-temperature properties, i.e., ultimate tensile strength ~613 MPa, yield strength ~564 MPa, and total elongation ~6.91%. Corrosion resistance was closely related to microstructural evolution during aging, and both prolonged aging and increased pre-deformation decreased the susceptibility to intergranular corrosion. The results provide a basis for optimizing the thermomechanical processing of 2A97 Al-Cu-Li alloys. Full article

Severe Cu and Pb enrichment in loess areas of northwestern China, mainly associated with mining and smelting activities, has increased the demand for efficient soil decontamination. Electrokinetic (EK) remediation is a promising in situ technology because it can drive ionic contaminants through low-permeability porous media with limited excavation and relatively low secondary disturbance. In this study, the effects of electric field strength, electrode type, and catholyte pH on Cu and Pb removal from contaminated loess were systematically evaluated using a large-scale EK reactor. The full name of EKG is electrokinetic geosynthetics. During treatment, pH, electrical conductivity, electric current, cumulative electroosmotic flow (EOF), and the spatial distributions of Cu and Pb were monitored. Increasing the electric field from 1.0 to 2.0 V cm⁻¹ increased current and EOF and accelerated anodic acid-front propagation, but it also strengthened cathodic alkalization and precipitation. Compared with graphite electrodes, electrokinetic geosynthetics (EKG) electrodes maintained higher current and EOF, generated stronger acidification, and increased Cu and Pb removal by approximately 25% and 5%, respectively. Among the tested catholyte conditions, pH 7.0 provided the best balance between electromigration and electroosmosis, achieving overall soil-phase removal efficiencies of approximately 19.0% for Cu and 8.0% for Pb. These results show that coordinated regulation of the electric field, electrode architecture, and electrolyte chemistry can mitigate the focusing effect in loess, although further enhancement is still required for field-scale decontamination. Full article

High-ammonium poultry digestate from thermophilic dry anaerobic digestion is often recycled, but excessive ammonia accumulation may inhibit anaerobic digestion and reduce process stability. This study developed a gas-driven ammonia stripping process coupled with gypsum-mediated absorption for digestate deammonification, nitrogen recovery, and CO₂-assisted carbonate formation. Laboratory stripping experiments were conducted using simulated biogas to evaluate the effects of pH, temperature, and gas–liquid ratio. Under the selected condition of pH 11, 65 °C, and a gas–liquid ratio of 2, NH₄⁺-N in 10 L digestate decreased from approximately 7980 to 1648 mg L⁻¹ within 12 h, corresponding to about 80% removal. In the absorption step, the slightly soluble CaSO₄ solution showed more stable NH₃ capture than the CaSO₄ suspension, and the corrected NH₃-N recovery reached approximately 90–95%. XRD, SEM-EDS, precipitate mass estimation, and gas-phase CO₂ variation supported the formation of CaCO₃-containing precipitates. Pilot-scale operation using real biogas further reduced NH₄⁺-N from approximately 8000 to 700–800 mg L⁻¹ during 36 h of extended pilot-scale operation. Overall, the coupled process provides a preliminary resource-recovery route integrating ammonia burden reduction, nitrogen recovery, sulfate transfer, and CO₂-assisted carbonate precipitation. However, full-scale sustainability still requires further long-term operation, complete nitrogen–carbon–calcium–sulfur mass balances, complete heat and energy-balance assessment, product-quality evaluation, and techno-economic or life-cycle assessment. Full article

The large-scale disposal of coal fly ash (CFA), coal bottom ash (CBA), and desulfurization gypsum (DG) from coal-fired power plants poses serious environmental challenges, driving the need for high-value utilization strategies. In this study, we propose a synergistic approach to prepare foam glass-ceramics from CFA, CBA, and DG via a sintering-foaming method. The effects of sintering temperature (1200–1230 °C) and DG content (0–5 wt.%) on phase composition, pore structure, and overall material properties were systematically investigated. The optimal sample, obtained at 1220 °C with 2 wt.% DG exhibits outstanding comprehensive performance: a bulk density of 1.0030 g/cm³, porosity of 62.09%, compressive strength of 9.66 MPa, and thermal conductivity of 0.6156 W/(m·K). Additionally, it demonstrates excellent chemical stability, with acid resistance exceeding 96% and alkali resistance over 98%, while the leaching concentrations of heavy metals (Pb, Cr, Cu, Zn) remain far below regulatory limits. Mechanistic analysis reveals a crystallization–foaming coupling effect. At an appropriate DG content (2 wt.%), a synergy is established: bubble formation provides heterogeneous nucleation sites that promote crystal precipitation, while moderate crystallization increases melt viscosity and stabilizes the pore structure. Conversely, excessive DG (3–5 wt.%) reduces melt viscosity, leading to bubble coalescence and rupture, suppressed crystallization, and consequently deteriorated material properties. This work provides a theoretical foundation for the synergistic utilization of multiple power plant wastes and the structure–property regulation of foam glass-ceramics. Full article

GPS-derived floating car data (FCD) provide spatially continuous urban traffic observations without fixed-sensor infrastructure. This study develops a spatiotemporal baseline framework jointly modelling day type and precipitation for 1189 junction-level nodes in Budapest. A six-phase pipeline—GPS preprocessing, coordinate reprojection, FME (Feature Manipulation Engine, Safe Software Inc., Surrey, BC, Canada)-based map-matching, junction-level aggregation, Voronoi meteorological allocation, and dataset assembly—was applied to 44.1 million 10 s records from approximately 1100 probe vehicles (November 2024–December 2025). Public holidays form a structurally distinct traffic flow pattern compared to Sundays (r = 0.71) and to regular workdays (r = 0.42); morning peak shifts to 09:00–11:00 and pooling holidays with Sundays introduces reference errors of 15–25%. Precipitation raises morning peak volumes by 6–17% across all zones while afternoon peaks remain statistically unchanged, consistent with commuter inertia; Saturday volumes fall by 7–15%. Rainy Wednesdays reach 109–112% of the Monday dry reference in inner zones, attributed to hybrid workers advancing their office day. Pairwise junction correlations show a non-monotonic distance-decay pattern, and time-lagged cross-correlation identifies 23 anticipative junction pairs with 60–90 min lead times. The results could potentially help decision making when developing city-wide infrastructure and tuning traffic signals so that traffic can be optimised and adapt to both real-time natural and social effects. The resulting baselines map onto DATEX II (Data Exchange standard, CEN EN 16157) ElaboratedDataPublication fields, supporting metadata publication on the Hungarian National Access Point under EU Regulation 2022/670/EU. Full article

Understanding vegetation sustainability is crucial for ensuring ecological security in dryland interior river systems. Focusing on the Manas River Basin in Xinjiang, our research extracted Landsat time-series data from 2000 to 2024 via Google Earth Engine, employing statistical approaches alongside Geodetector modeling to quantitatively evaluate the spatiotemporal dynamics of vegetation sustainability and its influencing factors. Our findings reveal that the basin’s Normalized Difference Vegetation Index (NDVI) displayed a significant upward trajectory (Sen’s slope = 0.010/yr, R² = 0.95, p < 0.01), with distinct temporal phases: the period 2000–2013 was characterized by rapid oasis expansion driven by cultivated land, while the period 2014–2024 was characterized by systematic vegetation improvement with a stabilizing land use pattern. Spatially, areas exhibiting extremely significant improvement accounted for 56.24% of the total basin area (concentrated mainly in artificial oases and the mid-mountain zone), and non-significant degradation accounted for only 1.89%. Land use type and soil texture were identified as the dominant spatial differentiation factors, followed by annual precipitation, with all pairwise factor interactions exhibiting enhancement effects. By identifying the optimal thresholds for vegetation growth (annual average temperature of 0.82–3.96 °C, elevation of 1826–2598 m, and loamy sand), this study defines the boundaries for sustainable vegetation development. These findings deliver a theoretical foundation for zonation management and habitat rehabilitation planning, supplying decision-making support for safeguarding regional ecological security and fostering sustainable development of oasis systems in arid Central Asia. Full article

Yttrium is one of the lesser-known critical elements, but it has recently gained significant market attention due to a dramatic price increase of up to 1400% in Europe. Although its primary application is in phosphors (e.g., in LEDs), modern society heavily depends on these technologies, making yttrium indispensable. However, the limited availability of yttrium raises concerns about its long-term supply. Therefore, there is a need for efficient techniques to recover yttrium from secondary materials to ensure a stable supply. While the wastes contain only trace amounts of yttrium and often have complex elemental compositions, they are more readily available than primary sources. The yttrium content ranges from a few percent in spent phosphors to several hundred ppm in red mud, around a few dozen ppm in phosphogypsum, and up to several ppm in coal and coal fly ashes. Although conventional hydrometallurgical methods are commonly used, they lack selectivity for yttrium recovery. In contrast, unconventional solvometallurgical and bioleaching approaches currently play a relatively minor role in recovery applications. This review discusses a range of methods investigated for yttrium recovery from different types of secondary resources, including pretreatment (where applicable), leaching, and subsequent yttrium recovery from the resulting leachates. Although the chemical and phase compositions of yttrium-bearing waste materials differ substantially, necessitating tailored treatment strategies, acid leaching remains the predominant extraction route and is most commonly followed by solvent extraction and/or oxalate precipitation. Most studies reported to date have been conducted at the laboratory scale. Despite progress and the development of promising recovery concepts, the efficient separation of high-purity yttrium from other rare earth elements and co-existing impurities continues to represent the key obstacle to commercial-scale application. Full article