Search Results (69)

Suspended particulate matter (SPM) plays a pivotal role in marine source-to-sink sedimentary systems. Internal solitary waves (ISWs), a prevalent hydrodynamic phenomenon, significantly influence vertical mixing, cross-shelf material transport, and sediment resuspension. Acting as energetic nonlinear waves, ISWs can disrupt the settling trajectories of suspended particles, enhance lateral transport above the pycnocline, and generate nepheloid layers nearshore. Meanwhile, intense turbulent mixing induced by ISWs accumulates large quantities of SPM at both the leading surface and trailing bottom of the waves, thereby altering the structure and dynamics of the intermediate nepheloid layers. This review synthesizes recent advances in the in situ observational techniques for SPM under the influence of ISWs and highlights the key mechanisms governing their interactions. Particular attention is given to representative field cases in the SCS, where topographic complexity and strong stratification amplify ISWs–sediment coupling. Finally, current limitations in observational and modeling approaches are discussed, with suggestions for future interdisciplinary research directions that better integrate hydrodynamic and sediment transport processes. Full article

This study investigates the influence of cerium nitrate (Ce(NO₃)₃·6H₂O) content on the performance of Ce(III)/CF/BN/EPN coatings intended for heat exchangers. A series of Ce(III)/carbon fibre (CF)/boron nitride (BN)/epoxy phenolic (EPN) coatings are fabricated with varying concentrations of Ce(NO₃)₃·6H₂O. The results of SEM and EDS show that the dissolution of cerium nitrate in acetone due to the particulate form causes it to be distributed in a diffuse state in the coating. This diffuse distribution does not significantly alter the porosity or structural morphology of the coating. With the increase in cerium nitrate content, both the EIS test results and mechanical damage tests indicate a progressive improvement in the corrosion resistance and self-healing properties of the coatings, while the thermal conductivity (TC) remains largely unaffected. The Ce in the coating reacts with the water molecules penetrating into the coating to generate Ce₂O₃ and CeO₂ with protective properties to fill the permeable pores inside the coating or to form a passivation film at the damaged metal–coating interface, which enhances the anticorrosive and self-repairing properties of the coating. However, the incorporation of Ce(NO₃)₃·6H₂O does not change the distribution structure of the filler inside the coating. As a result, the phonon propagation path, rate, and distance remain unchanged, leading to negligible variation in the thermal conductivity. Therefore, at a cerium nitrate content of 2.5 wt%, the coating exhibits the best overall performance, characterised by a |Z|_0.1Hz value of 6.08 × 10⁹ Ω·cm² and a thermal conductivity of approximately 1.4 W/(m·K). Full article

This study aimed to investigate phytoplankton dynamics and water quality at three drinking water intakes (Duchang, Hukou, and Xingzi) in Poyang Lake through monthly monitoring from May 2023 to April 2024. The results showed that a total of 168 species of phytoplankton were identified in nine phyla, and there were significant spatial and temporal differences in the abundance of phytoplankton at the three waterworks intakes, with a spatial trend of annual mean values of Duchang > Xingzi > Hukou and a seasonal trend of summer and autumn > spring and winter. The dominant species of phytoplankton in the waterworks intakes of the three waterworks also showed obvious spatial and temporal differences. Cyanobacteria (particularly Pseudanabaena sp. and Microcystis sp.) dominated the phytoplankton communities during summer and autumn, demonstrating significant water degradation potential. In contrast, Cyclotella sp. prevailed in winter and spring assemblages. Based on water quality assessments at the three intake sites, the Duchang County intake exhibited year-round mild eutrophication with persistent mild cyanobacterial blooms (June–October), while the other two sites maintained no obvious bloom conditions. Further analyzing the toxic/odor-producing algal strains, the numbers of dominant species of Pseudanabaena sp. and Microcystis sp. in June–October in Duchang County both exceeded 1.0 × 10⁷ cells·L⁻¹. It is necessary to focus on their release of ATX-a (ichthyotoxin-a), 2MIB (2-Methylisoborneol), MCs (microcystins), etc., to ensure the safety of the water supply at the intake. Building upon these findings, we propose a generalized algal monitoring framework, encompassing three operational pillars: (1) key monitoring area identification, (2) high-risk period determination, and (3) harmful algal warnings. Each of these is substantiated by our empirical observations in Poyang Lake. Full article

Pockmarks are globally distributed geomorphic features exhibiting diverse morphologies. Their geometric characteristics are commonly quantified by the radius-to-depth ratio. The evolutionary process of these features typically follows a cyclical pattern comprising initiation, expansion, stabilization, and decline. Submarine groundwater discharge (SGD), a seasonally modulated land–sea exchange process, exerts a significant influence on the formation and evolution of pockmarks. This influence is mediated through hydrodynamic forcing effects, sediment redistribution, and coupled chemical–biological interactions. This review systematically examines the formation mechanisms, evolutionary patterns, and primary controlling factors of pockmarks induced by SGD. It integrates recent research developments and global case studies to elucidate the dynamic interplay of multiple influencing factors. This study emphasizes the significance of interdisciplinary approaches in marine geological research and identifies key areas for future investigation. These insights aim to enhance risk assessment frameworks for marine hazards and inform marine spatial planning strategies. Full article

The rapid development of wireless network technology and the continuous evolution of network service demands have raised higher requirements for congestion control algorithms. In 2016, Google proposed the Bottleneck Bandwidth and Round-trip propagation time (BBR) congestion control algorithm based on the Transmission Control Protocol (TCP) protocol. While BBR offers lower latency and higher throughput compared to traditional congestion control algorithms, it still faces challenges. These include the periodic triggering of the ProbeRTT phase, which impairs data transmission efficiency, data over-injection caused by the congestion window (CWND) value-setting policy, and the difficulty of coordinating resource allocation across multiple concurrent flows. These limitations make BBR less effective in multi-stream competition scenarios in high-speed wireless networks. This paper analyzes the design limitations of the BBR algorithm from a theoretical perspective and proposes the Adaptive-BBR (Ad-BBR) algorithm. The Ad-BBR algorithm incorporates real-time RTT and link queue-state information, introduces a new RTprop determination mechanism, and implements a finer-grained, RTT-based adaptive transmission rate adjustment mechanism to reduce data over-injection and improve RTT fairness. Additionally, the ProbeRTT phase-triggering mechanism is updated to ensure more stable and smoother data transmission. In the NS3, 5G, and Wi-Fi simulation experiments, Ad-BBR outperformed all comparison algorithms by effectively mitigating data over-injection and minimizing unnecessary entries into the ProbeRTT phase. Compared to the BBRv1 algorithm, Ad-BBR achieved a 17% increase in throughput and a 30% improvement in RTT fairness, along with a 13% reduction in the retransmission rate and an approximate 20% decrease in latency. Full article

Northeast China, a traditional heavy industrial base, faces significant carbon emissions challenges. This study analyzes the drivers of carbon emissions in 35 cities from 2000–2022, utilizing a machine-learning approach based on a stacking model. A stacking model, integrating random forest and eXtreme Gradient Boosting (XGBoost) as base learners and a support vector machine (SVM) as the meta-model, outperformed individual algorithms, achieving a coefficient of determination (R²) of 0.82. Compared to traditional methods, the stacking model significantly improves prediction accuracy and stability by combining the strengths of multiple algorithms. The Shapley additive explanations (SHAP) analysis identified key drivers: total energy consumption, urbanization rate, electricity consumption, and population positively influenced emissions, while sulfur dioxide (SO₂) emissions, smoke dust emissions, average temperature, and average humidity showed negative correlations. Notably, green coverage exhibited a complex, slightly positive relationship with emissions. Monte Carlo simulations of three scenarios (Baseline Scenario (BS), Aggressive De-coal Scenario (ADS), and Climate Resilience Scenario (CRS)) the projected carbon peak by 2030 under the ADS, with the lowest emissions fluctuation (standard deviation of 5) and the largest carbon emissions reduction (17.5–24.6%). The Baseline and Climate Resilience scenarios indicated a peak around 2039–2040. These findings suggest the important role of de-coalization. Targeted policy recommendations emphasize accelerating energy transition, promoting low-carbon industrial transformation, fostering green urbanization, and enhancing carbon sequestration to support Northeast China’s sustainable development and the achievement of dual-carbon goals. Full article

Soy protein concentrate (SPC) is a cost-effective alternative to fish meal (FM) in aquaculture, but its deficiency in essential amino acids, particularly methionine, limits its application. This study evaluated the effects of methionine supplementation on growth, liver and intestinal health, and muscle quality in hybrid sturgeon (Acipenser baerii ♀ × A. schrenckii ♂) fed SPC-based diets. Four diets were formulated: an FM control diet, and SPC diets supplemented with 0% (M0), 0.25% (M2.5), and 0.50% (M5) methionine. Replacing FM with SPC without methionine (M0) significantly reduced weight gain and the protein efficiency ratio (PER) while increasing the feed conversion ratio (FCR) and hepatic lipid accumulation. Methionine supplementation (M5) restored growth performance, the PER, and muscle texture to levels comparable to the FM group. Intestinal enzyme activities (lipase and trypsin), villus height, and goblet cell counts significantly improved in the M5 group. Gene expression analysis showed that M5 upregulated tight junction genes (claudin1, occludin) and anti-inflammatory genes (tgfβ, lysozyme) while reducing pro-inflammatory cytokines (il1β, il8). In the liver, M5 reduced oxidative stress markers such as malondialdehyde (MDA) and improved antioxidant enzyme activities (SOD, CAT) while optimizing lipid metabolism, as evidenced by lower triglyceride (TG) and total cholesterol (TC) levels. Muscle quality analysis showed that M5 significantly increased muscle hardness, chewiness, and fiber density compared to M0. In conclusion, methionine supplementation at 0.50% effectively mitigates the negative effects of SPC, improving growth, liver and intestinal health, and muscle quality in hybrid sturgeon. Full article

The tubular flocculation reactor is a new and efficient device for treating algae-containing wastewater. The introduction of bubbles during the reaction process can effectively shorten the time required for floc separation. However, the impact of bubbles on floc formation and removal in the tubular flocculation reactor is not well understood. To further clarify the effect of bubbles on the reactor’s operation, this study employed a uniform experimental design, varying the flow rate, chemical dosage, bubble reaction distance, and bubble injection rate in the reactor to examine the influence of bubbles under different operating conditions. The results indicated that as the bubble reaction distance increased from 0 m to 7.6 m, the removal efficiency increased from 60% to 70%, the floc size increased from 160 μm to 165 μm, and the fractal dimension decreased from 2.1 to 1.9. When the bubble volume increased from 5% to 30%, the removal efficiency increased from 50% to 80%. Under constant bubble conditions, the rising speed of the flocs increased from 0.4 mm·s⁻¹ to 1.2 mm·s⁻¹, while the removal efficiency increased from 30% to 90%. A logarithmic correlation was observed between the rising speed and removal efficiency. A linear relationship was found between the floc rising speed and the floc size, with floc size increasing from 200 μm to 800 μm and the rising speed increasing from 0.4 mm·s⁻¹ to 2.3 mm·s⁻¹. An exponential relationship was found between the fractal dimension and the rising speed, with the rising speed decreasing from 2.3 mm·s⁻¹ to 0.4 mm·s⁻¹, while the fractal dimension increased from 1.93 to 2.02. Full article

The seeds of Zanthoxylum bungeanum seeds, a high-quality vegetable protein source, encounter application limitations due to their high molecular weight and anti-nutritional factors. This study focused on optimizing the fermentation process by investigating key parameters such as inoculation amount, inoculation ratio, material-to-liquid ratio, fermentation temperature, and fermentation time. Both single-factor experiments and response surface methodology were used to determine the optimal conditions. The effects of fermentation on particle size, surface morphology (scanning electron microscopy), water holding capacity, oil holding capacity, solubility, and emulsification properties of Zanthoxylum bungeanum seed protein were analyzed. In addition, acute toxicity was investigated at doses of 1.5 g/kg, 3 g/kg, 6 g/kg, and 12 g/kg. The results showed that the optimal fermentation conditions were an inoculum concentration of 10%, a ratio of Bacillus subtilis to Lactobacillus plantarum of 1:1, a material-to-liquid ratio of 0.8:1, a temperature of 35 °C, and a fermentation period of 4 days. Under these optimized conditions, the soluble protein content reached 153.1 mg/g. After fermentation, the functional properties of Zanthoxylum bungeanum seed protein improved significantly: the water holding capacity increased by 89%, the oil holding capacity by 68%, while the emulsifying activity and stability indices improved by 6% and 17%, respectively. The macromolecular proteins in the seeds of Zanthoxylum bungeanum were effectively broken down into smaller fragments during fermentation, resulting in a more folded and porous surface structure. In acute toxicity tests, all mice treated with fermented Zanthoxum seed protein survived for more than 7 days after injection, and there were no significant differences in body weight, organ index, and hematological tests between groups, but FZBSP of 1.5 g/kg~12 g/kg caused varying degrees of steatosis and inflammatory damage in the heart and liver. In conclusion, this study confirms that follow-up pilot studies using 1.5 g/kg FZBSP have the potential for further development and utilization. Full article

Under the impact of global climate change and human activities, the occurrence of compound disasters such as cascading landslides and flash floods caused by heavy rainfall is increasing. In response to these compound disaster events, it is important to simultaneously transport emergency resources from multiple emergency rescue points to the disaster sites to promptly control the cascading development of disasters and reduce the areas affected by the disasters and associated adverse impacts. This study proposes a dynamic game model for emergency resources dispatch to comprehensively consider the evolution of the compound disaster states and the timely dispatch of emergency resources from the rescue points to the disaster site. The dynamic game model is exemplarily applied to the emergency resource dispatch for a rainstorm-induced compound disaster that occurs in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA). Starting with the analysis of the characteristics of emergency resource management and the attributes of a cascading of heavy rainstorms, landslides, and flash floods, the game model simulates the dynamic game process between the “disaster state” and the “emergency resource manager” in the rescue operations. A two-stage dynamic game model can support decision-making with the objectives of minimal time cost and sufficient resource dispatch for the disaster sites. Game results show that the united emergency resource dispatch in the three GBA metropolitan areas can efficiently respond to compound disasters that occur within the GBA metropolitan area. The dynamic game model could be extended for compound disaster emergency responses with more complicated compound effects and resource constraints. Full article

The sintering process of Cu nanoparticle (Cu NP)/graphene nanoplatelet (GNP) composite solder paste was thoroughly investigated in this work through molecular dynamics simulations. The tensile properties of the sintered Cu NP/GNP composite solder paste were considered by using the uniaxial quasi-static tensile simulation method. The impact of sintering temperature, strain rate, and GNP addition on the tensile properties of Cu NP/GNP sintered structures was thoroughly investigated. The lattice structure, dislocation evolution, and atomic diffusion of the molecular dynamics results were analyzed using the common neighbor analysis (CNA), dislocation extraction algorithm (DXA), and mean square displacement (MSD) methods. The results of the post-processing analysis showed that the addition of GNP and the sintering temperature have an important influence on the mechanical properties of Cu NP/GNP sintered structures. In addition, the incorporation of GNP can significantly improve the mechanical properties of sintered Cu NP/GNP composite solder paste. More specifically, the tensile strength and fracture strain of the sintered composite solder paste will be increased by increasing the tensile strain rate. The strengthening mechanism of the sintered Cu NP/GNP composite solder paste can be attributed to the dislocation strengthening mechanism. Our study provides valuable insight for the development of high-performance composite solder paste with enhanced mechanical properties. Full article

In recent years, high-ductility concrete (HDC) has gradually become popular in the construction industry because of its excellent ductility and crack resistance. Concrete itself is a kind of building material with poor tensile properties, and it is necessary to add a large number of steel bars to improve its tensile properties, which increases the construction cost of buildings. However, most of the research studies on high-ductility concrete are scattered. In this paper, the basic mechanical properties of high-ductility concrete and the effects of dry and wet cycles, freeze–thaw cycles, and salt erosion on the durability of high-ductility concrete are obtained by comprehensive analysis. The results show that the tensile properties of HDC can be significantly improved by adding appropriate fiber. When the volume fraction of steel fiber is 2.0%, the splitting tensile strength of concrete is increased by 98.3%. The crack width threshold of concrete chloride erosion is 55–80 μm, and when the crack width threshold is exceeded, the diffusion of CL-1 will be accelerated, and the HDC can control the crack within the threshold, thereby improving the durability of the concrete. Finally, the current research status of high-ductility concrete is analyzed, and the future development of high-ductility concrete is proposed. Full article

The timely and accurate mapping of crop types is crucial for agricultural insurance, futures, and assessments of food security risks. However, crop mapping is currently focused on the post-harvest period, and less attention has been paid to early crop mapping. In this study, the feasibility of using Sentinel-1 (S1) and Sentinel-2 (S2) data for the earliest identifiable time (EIT) for major crops (sunflower, maize, spring wheat, and melon) was explored in the Hetao Irrigation District (HID) of China, based on the Google Earth Engine (GEE) platform. An early crop identification strategy based on the Random Forest (RF) model for HID was proposed, and the performance of the model transfer was evaluated. First, the median synthesis, linear shift interpolation, and the Savitzky–Golay (SG) filter methods were used to reconstruct the time series of S1 and S2. Subsequently, the sensitivity of different input features, time intervals, and data integration to different early crop identifications was evaluated based on the RF model. Finally, the model with optimal parameters was evaluated in terms of its transfer capacity and used for the early mapping of crops in the HID area. The results showed that the features extracted from S2 images synthesized at 10-day intervals performed well in obtaining crop EITs. Sunflower, maize, spring wheat, and melon could be identified 90, 90, 70, and 40 days earlier than the harvest date. The identification accuracy, measured by the F1-score, could reach 0.97, 0.95, 0.98, and 0.90, respectively. The performance of the model transfer is good, with the F1-score decreasing from 0 to 0.04 and no change in EIT for different crops. It was also found that the EIT of crops obtained using S1 data alone was 50–90 days later than that obtained using S2 data alone. Additionally, when S1 and S2 were used jointly, S1 data contributed little to early crop identification. This study highlights the potential of early crop mapping using satellite data, which provides a feasible solution for the early identification of crops in the HID area and valuable information for food security assurance in the region. Full article

The configuration of beam–column joints in precast concrete (PC) building structures varies widely, and different connection methods significantly affect the progressive collapse resistance of the structure. This study investigates the progressive collapse resistance of an innovative beam–column connection node frame. Finite element models of four-story, two-span space frame structures made of reinforced concrete (RC) and PC were developed using ANSYS 14.0/LS-DYNA R5.x software, employing nonlinear dynamic and static analysis to examine structural collapse behavior under bottom middle or corner column damage. Numerical results indicate that following the failure of the middle or corner column due to explosion loading, the vertical displacement and collapse rate of the PC structure with the novel connection method are less than those of the RC structure during collapse progression. Furthermore, upon removal of the middle or corner column, the residual load-carrying capacity of the PC structure with the innovative connection increased by 7% and 3.7%, respectively, compared to the RC structure. This suggests that PC structures with this type of connection demonstrate superior performance in resisting progressive collapse, offering valuable insights for future engineering applications. Full article

The cultivation of drip-irrigated rice has resulted in lower yields. However, the decrease in rice yield under drip irrigation and its relationship with the existing water and N regime have not been fully explained. Research and development of optimized water and N-management techniques are crucial for increasing rice yield under drip irrigation. In this study, two irrigation treatments were set: conventional drip irrigation (DIO) and drip irrigation with water stress (DIS). Each irrigation treatment contained four N rates: urea N 240 kg ha⁻¹ (LN), urea N 300 kg ha⁻¹ (MN), urea N 360 kg ha⁻¹ (HN), and ammonium sulfate N 300 kg ha⁻¹ (AN). The soil’s ammonium and nitrate contents were measured on the 2nd and 28th days after N application at panicle initiation stage. At anthesis, the aboveground and root biomass of rice were measured. In heading and maturity stage the N content of aboveground was measured and the yield, yield components, and NPFP were assessed at maturity stage. The results showed the following: (1) On the second day after N application, the contents of soil NO₃⁻-N and NH₄⁺-N in the 0–10 cm soil layer were highest for both the DIO and DIS. On the 28th day after N application, the soil NO₃⁻-N content was highest at the 20–40 cm depth, while the soil NH₄⁺-N content was still highest at the 0–10 cm depth. (2) The aboveground and root biomass in DIO treatment were significantly higher than in DIS. Furthermore, the root biomass at the 0–10 cm depth was significantly greater than at the 10–50 cm depth for both the DIO and DIS treatments. In the DIO treatment, the root biomass at the 10–50 cm depth was significantly higher with the HN and AN treatments compared to MN. However, in the DIS treatment, the root biomass at the 10–50 cm depth did not show significant differences between the MN, HN, and AN. (3) N accumulation in rice was significantly higher for the DIO treatment compared to the DIS treatment. Under the same irrigation treatment, the N accumulation in rice was highest in the AN and lowest in the LN. The PrNTA and PrNTC in DIS were significantly higher than in DIO, while the PoNAA and PoNAC were significantly lower in DIS. (4) The number of panicles, spikelets per panicle, seed-setting rate, 1000-grain weight, and grain yield were significantly lower in DIS. Under the DIS, these parameters were not significantly different among the MN, HN, and AN. In the DIO, the seed-setting rate, 1000-grain weight, and yield were not significantly different between the HN and AN, but were significantly higher than in the MN and LN. (5) NPFP was significantly higher in the DIO compared to the DIS. Among the different N rates, NPFP was highest with the AN treatment and lowest with the LN. In summary, under drip irrigation, there was a mismatch between soil mineral N and the distribution of rice roots, leading to reduced N accumulation and utilization in rice, ultimately impacting yield formation. Increasing N application and soil ammonium nutrition can improve rice yield under drip irrigation. However, optimizing N fertilizer management may not increase rice yield further when irrigation is further limited. Full article