Search Results (541)

Currently, research on the hydrodynamic characteristics of artificial reef deployment still faces challenges such as insufficient environmental coupling, but accurate simulation of the deployment process holds significant engineering importance for optimizing deployment efficiency and ensuring reef stability. This study employs the Smoothed Particle Hydrodynamics (SPH) method to establish a 3D numerical model, focusing on the influence of key parameters—inflow velocity and water entry angle—on the hydrodynamic characteristics of cubic artificial reef deployment. The results indicate that under flow velocities of 0.4–0.5 m/s, pressure fluctuations are relatively minor, with peak pressure gradients below 15 kPa/m, exhibiting a gradual trend, while particle concentration remains high, and drag gradually increases. At flow velocities of 0.6–0.8 m/s, the maximum pressure at the bottom reaches up to 35 kPa, with low-pressure areas at the tail dropping to −10 kPa; particle concentration decreases compared to conditions at 0.4–0.5 m/s; settling time extends from 8.4 s to 12 s, representing a 42% increase. Under different water entry angles, drag varies nonlinearly with the angle, reaching its maximum at 20° and its minimum at 25°, with a reduction of approximately 47% compared to the maximum. The anti-sliding safety factor and anti-overturning safety factor are used to assess the stability of the cubic reef placed on the seabed. Across different inflow velocities, the anti-sliding safety factor of the cubic artificial reef significantly exceeds 1.2, whereas the anti-overturning safety factor is below 1.2 at 0.4 m/s but exceeds 1.2 at velocities of 0.5 m/s and above, indicating that the reef maintains stability under the majority of these flow conditions. Our findings provide a scientific basis for the deployment process, site selection, and geometric design of cubic artificial reefs, offering valuable insights for the precise deployment and structural optimization of artificial reefs in marine ranching construction. Full article

In the loess region, the hydraulic properties of the loess, used as either surrounding rock, backfilling or geoplomer material, are significant for engineering construction and agriculture development projects. This work investigated the soil-water characteristic curves (SWCC) of the undisturbed and remolded loess during the drying process using the tensiometer and psychrometer method. Based on the test results, SWCC was fitted using the Van Genuchten, and Fredlund and Xing models. Moreover, the permeability was comparatively calculated by the Childs and Collis-George, Van Genuchten, and Fredlund models, respectively. Results revealed that the SWCC of both the undisturbed and remolded loess exhibited three-stage characteristics in the relationship between the logarithmic matric suction and moisture, including the boundary effect zone, transition zone, and residual zone. The corrected Fredlund and Xing model provided an optimal calculation for the SWCC of the loess, while the Van Genuchten model showed suction deviations of about 103 kPa. Meanwhile, the undisturbed loess had a low water retention at the low (<103 kPa) suction range, which was attributed to the large pore structure of the undisturbed loess that reduces the air-entry value. This research clarified the differences in the water retention and permeability properties of the loess, providing a theoretical foundation for evaluating the hydraulic properties of the loess. Full article

Appliance recognition from aggregate household measurements is challenging under real deployment conditions, where multiple devices operate concurrently and sensor data are affected by imperfections such as noise, missing samples, and nonlinear meter response. In contrast to many studies that rely on curated or idealized datasets, this work investigates appliance recognition using real multimodal utility data (electricity, water, gas) collected at the building entry point, in the presence of substantial uninstrumented background activity. We present a case study evaluating transparent, rule-based detectors designed to exploit characteristic temporal dependencies between modalities while remaining interpretable and robust to sensing imperfections. Four household appliances—washing machine, dishwasher, tumble dryer, and kettle—are analyzed over six weeks of data. The proposed approach achieves reliable detection for structured, water-related appliances (22/30 washing cycles, 19/21 dishwashing cycles, and 23/27 drying cycles), while highlighting the limitations encountered for short, high-power events such as kettle usage. The results illustrate both the potential and the limitations of conservative rule-based detection under realistic conditions and provide a well-documented baseline for future hybrid systems combining interpretable rules with data-driven adaptation. Full article

Chromium (Cr) toxicity poses a significant challenge to agricultural productivity, human health, and food security. Biochar (BC) is a versatile amendment employed to alleviate Cr toxicity. Chromium stress impairs growth by inducing membrane damage and cellular oxidation, as well as inhibiting chlorophyll synthesis, photosynthetic efficiency, water uptake, and nutrient absorption. This review consolidates information on the mechanisms through which BC mitigates Cr stress. Biochar facilitates Cr immobilization by reduction, adsorption, precipitation, and complexation processes. It enhances growth by improving photosynthetic efficiency, water and nutrient uptake, osmolyte synthesis, and hormonal balance. Additionally, biochar promotes resilient bacterial communities that reduce Cr and enhance nutrient cycling. The effectiveness of BC is not universal and largely depends on its feedstock properties and pyrolysis temperature. This review provides insights into soil quality, plant function, and human health, which contribute to providing a comprehensive assessment of the capacity of BC to mitigate Cr toxicity. This review highlights that BC application can reduce Cr entry into the food chain, thus decreasing its health risk. This review also identifies knowledge gaps and outlines future research directions to increase the efficiency of BC in mitigating Cr toxicity. This review also offers insights into the development of eco-friendly measures to remediate Cr-polluted soils. Full article

The oblique water-entry stability of hollow projectiles with different aperture ratios (d/D) and aspect ratios (L/D) is investigated numerically in this study. The effects of aperture and aspect ratios on cavity evolution, hydrodynamic forces, and projectile motion are disclosed and discussed. When aperture ratios vary from 0.2 to 0.7, a larger aperture ratio results in a longer through-hole jet, earlier cavity closure, and a smaller cavity with less vapor. The best water-entry stability with minimal projectile deflection occurs at d/D = 0.3. For d/D > 0.4, the projectile tends to rotate clockwise and touch the surrounding cavity with a rapid increase in the lift, drag, and moment coefficients, accelerating the velocity decay. When aspect ratios vary from 2 to 7, the transition from stability to instability in the projectile motion is predicted at L/D = 2.75~3. A lower aspect ratio (L/D = 2) promotes stable motion with a steady drag coefficient (C_d ≈ 0.9) and negligible lift and moment. In contrast, the instability occurs at L/D = 3. However, when L/D > 3, the water-entry stability is enhanced with the increasing aspect ratio due to greater projectile mass. The inflection points in the hydrodynamic forces are also delayed and the hollow projectiles penetrate further. Full article

Significant achievements have been made in the control of point source pollution. However, agricultural non-point source pollution (AGNPSP) has become a serious threat to ecological environment quality and is now the main source of pollution in the Yangtze River Basin. The topographical features of the upper Yangtze River region are primarily characterised by hilly and mountainous terrain, marked by steep slopes and pronounced undulations. This renders the land susceptible to soil erosion, thereby becoming a significant conduit for the entry of AGNPSP into water bodies. Consequently, there is an urgent need to identify critical sources, areas and periods of AGNPSP and to promote the effective prevention and control of such pollution. The present study adopted the Yongchuan District of Chongqing, a region characterised by hilly and mountainous terrain in the upper reaches of the Yangtze River, as a case study. The research, conducted from 2018 to 2021, sought to identify the “critical sources—areas—periods“ of AGNPSP. In order to surmount the challenge posed by the absence of fundamental data, the study constructed and integrated three models. The export coefficient model was used to calculate the pollution load, the pollutant load intensity model was used for spatial analysis, and the equal-scale pollution load equation was used to assess the contribution degree of different pollutants. Furthermore, the study developed a monthly pollutant flux model to accurately identify the critical pollution periods within the year. In conclusion, the research results have indicated the necessity of a governance strategy that is to be implemented with utmost priority. This strategy is to be based on the following hierarchy: critical sources, areas, and periods. The results of the study indicate the following: (1) The pollutants that exhibit the greatest contribution in Yongchuan District are total nitrogen (TN)and chemical oxygen demand (COD), accounting for 34% and 33%, respectively. The primary source of pollution is attributed to livestock and poultry breeding, accounting for 49.7% of the total pollution load. (2) The critical area of AGNPSP in Yongchuan District is located in the south of the district and primarily comprises Zhutuo Town, Hegeng Town and Xianlong Town. Among the critical areas identified, livestock and poultry farming accounts for 68% of the pollution load. (3) The monthly variation of pollutant fluxes demonstrates a single peak pattern, with the peak occurring in June. The data indicates that the flux of pollutants in June and July accounted for 37% of the total, thus identifying these months as critical periods for the management of AGNPSP in Yongchuan District. The critical source–area–period analysis indicates that the comprehensive management strategy for AGNPSP should focus on critical sources, areas and periods. Furthermore, it should adopt a prioritised, zoned and phased management approach. This approach has the potential to promote cost-effective and efficient prevention and control, thereby facilitating the achievement of sustainable agricultural development. Full article

Remediating cadmium (Cd) contamination in aquatic and terrestrial environments has become an urgent environmental priority. Biochar has been widely employed for heavy metal removal due to its wide availability, strong adsorption capacity, and potential for recycling agricultural waste. In this study, samples of alkali–Fe-modified biochar (Fe@NaOH-SBC, Fe@NaOH-HBC, and Fe@NaOH-MBC) were prepared from agricultural wastes (ginger straw, Sichuan pepper branches, and kiwi leaves) through NaOH and FeCl₃·6H₂O modification. A comprehensive characterization confirmed that the alkali–Fe-modified biochar exhibits a higher specific surface area, richer functional groups, and successful incorporation of the iron oxides Fe₃O₄ and α-FeOOH. The fitting parameter qmax from the Langmuir model indicates that the alkali–Fe modification of carbon significantly enhanced its maximum capacity for Cd²⁺ adsorption. Furthermore, a synergistic effect was observed between iron oxide loading and alkali modification, outperforming alkali modification alone. Furthermore, a 30-day soil incubation experiment revealed that the application of alkali–Fe-modified biochar significantly increased soil pH, SOM, and CEC while reducing the available cadmium content by 13.34–33.94%. The treatment also facilitated the transformation of highly bioavailable cadmium species into more stable, less bioavailable forms, thereby mitigating their potential entry into the food chain and the associated human health risks. Moreover, short-term spinach seed germination experiments confirmed that treatments with varying additions of alkali–Fe-modified biochar mitigated the inhibition of seed physiological processes by high concentrations of available cadmium to varying degrees. Overall, this study provides a sustainable and effective strategy for utilizing agricultural waste in the remediation of cadmium-contaminated water and soil systems. Full article

Accurate evaluation of unsaturated shear strength remains a significant challenge in geotechnical engineering because of the nonlinear interaction between matric suction and shear strength. Existing models often assume a linear contribution of suction and are generally restricted to low suction ranges, limiting their predictive capability under highly unsaturated conditions. This study investigated the nonlinear response of unsaturated shear strength through single-stage direct shear tests conducted under constant water content. Two soil types: a high-plasticity clay and a low-plasticity silty clay were examined across a wide suction range extending beyond the air-entry value (AEV). The results revealed a nonlinear behavior expressed as a distinct bi-linear trend, with shear strength increasing with suction up to the optimal moisture condition and then exhibiting a clearly altered rate of increase at higher suction levels. To capture this nonlinear behavior of unsaturated shear strength with suction, an exponential shear strength equation was proposed and validated using eight additional published datasets encompassing different soil classifications and suction magnitudes. The proposed formulation demonstrates that accounting for non-linearity is essential for accurately estimating the unsaturated shear strength of the soil. Moreover, the proposed exponential model outperforms both the well-established linear model of Fredlund and the nonlinear power law model of Abramento and Carvalho, thereby providing a unified framework for capturing the nonlinear interaction of matric suction on unsaturated shear strength. Full article

The enormous applications of various nanoparticles (NPs) have raised the possibility that humans may be simultaneously exposed to mixtures of them in real life. Realistically, this situation may apply to plastic NPs, mainly derived from the breakdown of larger plastics, and to silver NPs, both of which are among the most frequently detected NPs in the envirnment due to their applications in healthcare, consumer products, and water purification. Although numerous studies have examined the toxicity of plastic and silver NPs individually, knowledge of their combined toxicity remains limited. Hence, the main objective of our study was to investigate the toxicity of high-density polyethene nanoparticles (HDPE NPs), thermally isolated from food-cooking bags, in combination with citrate-stabilised silver nanoparticles (AgNPcit) to Caco-2 and HT29MTX cells growing in 2D monoculture or in 3D triple-culture with Raji cells. Cellular uptake of NPs was quantified from the side-scatter (SSC) signal in flow cytometry; toxicity was evaluated by the neutral red assay; apoptosis was evaluated by the Annexin V method; and induction of oxidative stress was evaluated by a fluorescent method using DCFDA and DHR probes. Both cell lines took up both types of NPs; however, HT29MTX cells were more effective in the NPs’ uptake. Interestingly, HDPE NPs and AgNPcit mutually inhibited each other’s uptake, which suggests a similar mechanism of entry. Both types of NPs were toxic to both cell lines growing in monoculture; Caco-2 cells were more susceptible than HT29MTX. The toxicity was attributed to the induction of oxidative stress and associated apoptosis. In line with the mutual inhibition of the NPs’ uptake, the toxic effect of both NPs in the mixture was less than that expected as the sum of individual treatments. The toxic effects of both NPs or their mixture were less pronounced in the triple-culture Caco-2/HT29MTX/Raji, than in Caco-2 and HT29MTX growing in monoculture. Full article

Antibiotics are widely used in medicine, livestock and other fields, leading to increasingly prominent enrichment, transformation and potential ecological risks in the global water environment. This poses a serious threat to ecological balance and public health, making the development of efficient and economical treatment technologies a research hotspot for addressing water antibiotic pollution. This paper systematically analyzes the current status of global water antibiotic pollution, migration and transformation characteristics, and research progress in removal technologies. We summarize the main types of antibiotics in water and their spatial distribution across different global water bodies, explore their primary entry pathways into the water environment, and elaborate on transformation behaviors such as migration, adsorption and degradation, as well as residual risks to aquatic ecosystems and human health. We also focus on existing artificial removal technologies, including physical methods like adsorption and membrane separation, chemical methods centered on advanced oxidation, and biological methods utilizing microbial metabolism. And we discuss emerging technologies such as microbial fuel cells and biocatalyst remediation, along with hybrid processes, regarding their development status and application potential. Finally, we outline key challenges in practical application of current technologies, provide an outlook on future research directions and engineering applications, aiming to offer references for water antibiotic pollution control. Full article

Landslide impacts into water generate impulse waves that, in confined basins and along steep coasts, escalate swiftly into hazardous near-shore surges. In this study, we present a scenario-aware workflow using gradient boosting and k-means clustering, and explain them using Shapley additive explanations (SHAPs). Two cases are addressed: forecasting at water entry (Scenario I) with predictors Froude number $Fr$, relative effective mass M, and relative thickness S; and pre-event assessment (Scenario II) with predictors Bingham number $Bi$, relative moving length L, and relative initial mass $Mi$. Using 270 controlled physical-model experiments, we benchmark six learning algorithms under 5-fold cross-validation. Gradient boosting delivers the best overall accuracy and cross-scenario robustness, with XGBoost close behind. Scenario I attains a coefficient of determination $R^2$ of 0.941, while Scenario II achieves $R^2=0.865$. Residual analyses indicate narrower spreads and lighter tails for the top models. SHAP reveals physics-consistent controls: M and $Fr$ dominate Scenario I, whereas initial mass and the $Bi$ dominate Scenario II; interactions $Fr\times S$ and $Mi\times Bi$ clarify non-linear amplification of wave amplitude and height. The cluster–predict–explain framework couples predictive skill with physical transparency and is directly applicable to coastal hazard screening and integration into shoreline early-warning workflows. Full article

The construction of urban ecological security patterns (ESPs) is an effective approach for managing ecological space and preventing the uncontrolled expansion of urban areas, thereby safeguarding the ecological security of urban agglomerations. This study focuses on the Changsha–Zhuzhou–Xiangtan Urban Agglomeration (CZTUA), utilizing an ESP framework based on ecosystem services, ecological sensitivity, landscape connectivity, and resistance surfaces (SSCR). The spatio-temporal evolution and driving forces of ESP were analyzed for 2010, 2015, and 2020. Based on this, the ecological control zones of the CZTUA were delineated according to ecosystem importance, and appropriate ecological improvement strategies were proposed. The findings revealed the following: (1) The number of ecological sources in the CZTUA decreased from 26 to 23, while their total area expanded from 1113.6 km² to 3013.96 km², indicating a “point-to-patch” development trend. Ecological corridors showed a “decrease–increase”trend in number, but their total length consistently contracted from 1025.69 km to 536.25 km, with greater emphasis on the efficiency and effectiveness of connecting habitats. Ecological nodes decreased from 14 to 5, while their aggregate area increased from 290.6 km² to 1796.48 km², mirroring changes in ecological sources. (2) Ecological sources, corridors, and nodes in the CZTUA are primarily located in the eastern mountainous and hilly regions, with a trend of expansion toward the western areas. The spatial distribution of corridors and nodes is shaped by these sources, with dense areas exhibiting short-distance networks and dispersal areas showing long-distance linear patterns. Node distribution shifts from entry/exit areas of ecological sources and corridors to the sources themselves. (3) The spatio-temporal evolution of the ESP in the CZTUA is driven by a dual-wheel mechanism of “natural foundation-policy regulation,” where precipitation and potential evapotranspiration serve as the primary natural drivers, manifested through water conservation. (4) The region is divided into three control levels: the core protected areas focus on ecological protection in the eastern mountainous and hilly regions; the ecological buffer areas emphasize ecological coordination in transitional landforms such as hills, medium-undulating mountains, and platforms; the intensive development areas, mostly located in platform, plain, and some hilly areas, prioritize ecological optimization. The three-tier control zones implement strategies of strict protection, buffering and coordination, and optimized development, respectively, providing a direct basis for the refined management of ecological spaces. Full article

Microplastics (MPs) are increasingly recognized as emerging contaminants in aquatic environments; however, their occurrence and fate in tropical wastewater treatment systems remain poorly understood. This study provides the first inland–island comparison of MP removal in wastewater treatment plants (WWTPs) across Thailand’s Eastern Economic Corridor. Influent and effluent samples were collected from six WWTPs, encompassing five treatment types: oxidation ditch, aerated lagoon, stabilization pond, aerated tank, and sand filtration combined with reverse osmosis. Polymeric composition and size distribution were examined in parallel with conventional water quality indicators. Across all sites, polyethylene (PE) and polypropylene dominated influent MPs, together accounting for 57–92% of total abundance. Inland plants received heterogeneous municipal wastewater, including domestic inputs and agricultural runoff. In contrast, island facilities consistently showed PE-enriched influents (45–60%) in site F, reflecting tourism-driven reliance on single-use plastics and personal care products. In addition, several minor polymers were identified, including poly (vinyl stearate) (up to 26%), polyamide, polytetrafluoroethylene and ethylene–butyl acrylate, highlighting overlooked pathways of MP entry into WWTPs. Fine MPs (100–300 μm) comprised over two-thirds of influent particles, with stabilization ponds reaching 16,000 MP m⁻³. Removal efficiency ranged from 86.0% to 98.5%. Spearman’s correlation and multiple linear regression analyses revealed strong positive relationships between MPs and both total suspended solids (TSS) and turbidity. Suspended solids parameters emerged as the most reliable predictor of MP abundance (adjusted R² = 0.91, p = 0.001). This finding highlights TSS coupled with turbidity as a practical, cost-effective indicator for monitoring MPs in tropical WWTPs. To achieve greater accuracy, a larger dataset should be built and further analyzed. Full article

Urban green spaces are essential components of city ecosystems, providing environmental and social benefits while simultaneously serving as potential entry points for invasive plant pathogens. In recent years, increasing attention has been directed toward the role of urban environments as reservoirs and transmission corridors for oomycetes, a group of highly destructive microorganisms affecting trees and shrubs. This study aimed to investigate the diversity and potential introduction pathways of oomycetes in three Warsaw parks representing distinct ecological settings: a historical city park, a large landscape park with aquatic features, and a newly constructed linear park. Samples of soil, and surface water were collected and analysed using standard isolation and molecular identification methods. Four species were identified: Phytophthora cactorum, P. cambivora, Phytopythium vexans, and Ph. montanum—the latter two representing first records for urban parks in Poland. The results indicate that nursery plant material, surface water systems, and wildlife activity, particularly birds, are likely contributors to the introduction and spread of these pathogens in city landscapes. The findings underscore the growing phytosanitary risk associated with urban greenery, where the interplay of anthropogenic disturbance, high plant turnover, and complex hydrological networks facilitates pathogen establishment. This research highlights the urgent need to integrate urban biosecurity strategies with routine molecular monitoring, nursery inspections, and wildlife surveillance to limit further dissemination of invasive oomycetes and enhance the resilience of urban tree populations. Full article

The study examines the use of environmentally friendly materials, such as metakaolin and cement, in various proportions to stabilize expansive plastic soils and assess their effects on the soil–water characteristic curve (SWCC). Metakaolin, a supplementary cementitious material with a lower carbon footprint than ordinary cement, enhances soil behavior through pozzolanic reactions. The incorporation of metakaolin and cement reduced the fitting parameter “a,” linked to the air-entry value (AEV), indicating that treated soils desaturate at lower suction values due to improved aggregate formation and pore structure. With increasing stabilizer content, the SWCC shifted toward lower suction values, reflecting improved hydraulic performance and reduced moisture sensitivity. The fitting parameter “n,” representing desaturation capacity and pore size distribution, increased with stabilizer content, suggesting a more uniform and durable soil structure. Overall, using metakaolin and cement enhances expansive soils’ structural and hydraulic behavior while conserving cement and reducing CO₂ emissions. Machine learning models, Random Forest (RF), Decision Tree (DT), and Artificial Neural Network (ANN), were developed to predict SWCC. The RF model achieved the best accuracy (R² = 0.9063, adjusted R² = 0.8631), demonstrating the reliability of ML in evaluating green soil stabilization methods. Full article