Organic matter (OM), total nitrogen (TN), organic phosphorous (OP) and total phosphorous (TP)content of soil in northwest water-level fluctuating zone (WLFZ) of Lake Chaohu under natural and different artifi...Organic matter (OM), total nitrogen (TN), organic phosphorous (OP) and total phosphorous (TP)content of soil in northwest water-level fluctuating zone (WLFZ) of Lake Chaohu under natural and different artificial conditions were ana- lyzed to study the variation of OM, TN, OP and TP. It showed: Flooding and air- drying help to increase soil OM content in study area. Process of flooding and air- drying is conducive to soil adsorption of nitrogen and it can enhance spatial hetero- geneity of soil OM, TN, OP, process of flooding and air-drying also can reduce the difference of TP contents among different points. Riprap embankment is not con- ducive to maintaining soil organic matter under flooded conditions, emergent plants are conducive to maintaining soil organic matter under flooded conditions. Soil with high nitrogen content will release nitrogen to overlying water under flooded condi- tions. Under drying after flooding conditions, demand for phosphorus of vegetation growth will reduce TP content in soil, bare area will enrich phosphorus, when the next flood cover up a greater release of phosphorus will happen展开更多
Flooding stress is a major adverse condition during the emergence period of direct-seeded rice.This study investigated the use of wood vinegar as a seed soaking treatment to enhance rice seedling rates under flooding ...Flooding stress is a major adverse condition during the emergence period of direct-seeded rice.This study investigated the use of wood vinegar as a seed soaking treatment to enhance rice seedling rates under flooding stress,exploring both the methodology and physiological mechanisms involved.The optimal seed soaking concentration was determined through a gradient experiment,followed by a multi-cultivar validation test.The physiological mechanism of wood vinegar soaking on seedling emergence was analyzed by measuring the electrical conductivity of the flooding water,the changes in starch and soluble sugar contents in the grains and sprouts,and the dynamics ofα-amylase activity and antioxidant-related enzyme activities in the sprouts.The results showed that soaking rice seeds in a wood vinegar solution at a low concentration significantly enhanced the emergence of rice seedlings under flooding conditions,with a 100-fold dilution having the most pronounced effect,increasing seedling rates by 50.6%-60.0%.Further analysis indicated that wood vinegar treatment enhanced seedling establishment by inducing a significant increase inα-amylase activity,leading to a 74.9%-213.6%increase in soluble sugar content in the sprouts during 2-8 d after flooding stress compared with the control.Additionally,the treatment increased superoxide dismutase and peroxidase activities in the sprouts,mitigating lipid peroxidation of the cell membranes,and notably lower water electrical conductivity was observed in wood vinegar-treated seeds compared with the control.In conclusion,soaking rice seeds in a 100-fold diluted wood vinegar solution improves rice seedling rates under flooding stress by mitigating oxidative damage and maintaining energy supply.This approach is valuable for developing cost-effective seed treatment technologies and offering novel strategies to improve seedling rates and uniformity of direct-seeded rice under flooding conditions.展开更多
[Objective]Surface water flooding is caused by heavy rainfall,which has been the main type of flooding in many cities across the world.Real urban environments are highly complex,and there are numerous parameters influ...[Objective]Surface water flooding is caused by heavy rainfall,which has been the main type of flooding in many cities across the world.Real urban environments are highly complex,and there are numerous parameters influencing the rainfall-runoff processes,such as road width,orientation and building coverage.The main objective is to perform a parametric study concerning the rainfall-runoff processes in complex urban environments,in order to gain a better understanding of the impact of urban characteristics on the surface runoff.[Methods]Realistic urban layouts are generated by means of procedural modelling software,which parameterises the urban configurations using 11 independent variables,including the averaged street length,street orientation,street curvature,major street width,minor street width,park coverage,etc.A shock-capturing TVD MacCormack shallow water equations solver is used to undertake a large number of computational simulations regarding the rainfall-runoff processes over realistic urban layouts.The dominating urban parameters that influence the time of concentration is unveiled,which characterises the timescale of the flood formation.[Results]In order to generalise the research outcomes,the obtained hydrographs at the outlet of the catchment are normalised so that they are independent of the catchment area,slope or rainfall intensity.The dimensionless time of concentration is thus only the functions of 12 independent parameters,including 11 parameters that governing the urban layouts and the Manning roughness coefficient of the ground.A sensitivity analysis,based on the multiple linear regression method,is performed on the 2,994 simulation cases to quantify the influence of each parameter.[Conclusion]The results show that the ground roughness and the building coverage ratio are the two most important factors that influence the urban flood formation.Their influences on the dimensionless timescale of the urban catchments’response to rainfall are quantified by empirical formulae.The research findings can provide useful guidelines for the design of future flood-resilient urban environments and the improvement of existing drainage systems in cities.展开更多
Soil microorganisms and labile soil organic carbon(SOC)fractions are essential factors affecting greenhouse gas(GHG)emissions in paddy fields.However,the effects of labile SOC fractions and microorganisms on GHG emiss...Soil microorganisms and labile soil organic carbon(SOC)fractions are essential factors affecting greenhouse gas(GHG)emissions in paddy fields.However,the effects of labile SOC fractions and microorganisms on GHG emissions from flooding to drying after organic fertilizer replacing for chemical fertilizer remain unclear.Here,a long-term experiment was conducted with four treatments:chemical fertilization only(control),organic fertilizer substituting 25%of chemical N fertilizer(NM1),50%of chemical N fertilizer(NM2),and NM2combined with crop straw(NMS).GHG emissions were monitored,and soil samples were collected to determine labile SOC fractions and microorganisms.Results revealed the GHG emissions in the NM2 significantly increased by 196.88%from flooding to drying,mainly due to the higher CO_(2) emissions.The GHG emissions per kg of C input in NMS was the lowest with the value of 9.17.From flooding to drying,organic fertilizer application significantly increased the readily oxidizable organic carbon(ROC)contents and C lability;the NM2 and NMS dramatically increased the SOC and non-readily oxidizable organic carbon(NROC).The bacterial communities showed significant differences among different treatments in the flooding,while the significant difference was only found between the NMS and other treatments in the drying.From flooding to drying,changing soil moisture conditions causes C fractions and microbial communities to jointly affect carbon emissions,and the NMS promoted carbon sequestration and mitigated GHG emissions.Our findings highlight the importance of the labile SOC fractions and microorganisms linked to GHG emissions in paddy fields.展开更多
The Taklimakan Desert,located in the heart of central Asia,covers approximately 330000 km^(2),making it China's largest desert and the world's second-largest shifting desert(Dong et al.,2024).With an average a...The Taklimakan Desert,located in the heart of central Asia,covers approximately 330000 km^(2),making it China's largest desert and the world's second-largest shifting desert(Dong et al.,2024).With an average annual precipitation of less than 100 mm and evaporation rates ranging from 2000 to 3000 mm(Yang et al.,2020),it is recognized as one of the driest regions on Earth,often referred to as the“sea of death”.展开更多
Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer...Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.展开更多
Floods and storm surges pose significant threats to coastal regions worldwide,demanding timely and accurate early warning systems(EWS)for disaster preparedness.Traditional numerical and statistical methods often fall ...Floods and storm surges pose significant threats to coastal regions worldwide,demanding timely and accurate early warning systems(EWS)for disaster preparedness.Traditional numerical and statistical methods often fall short in capturing complex,nonlinear,and real-time environmental dynamics.In recent years,machine learning(ML)and deep learning(DL)techniques have emerged as promising alternatives for enhancing the accuracy,speed,and scalability of EWS.This review critically evaluates the evolution of ML models—such as Artificial Neural Networks(ANN),Convolutional Neural Networks(CNN),and Long Short-Term Memory(LSTM)—in coastal flood prediction,highlighting their architectures,data requirements,performance metrics,and implementation challenges.A unique contribution of this work is the synthesis of real-time deployment challenges including latency,edge-cloud tradeoffs,and policy-level integration,areas often overlooked in prior literature.Furthermore,the review presents a comparative framework of model performance across different geographic and hydrologic settings,offering actionable insights for researchers and practitioners.Limitations of current AI-driven models,such as interpretability,data scarcity,and generalization across regions,are discussed in detail.Finally,the paper outlines future research directions including hybrid modelling,transfer learning,explainable AI,and policy-aware alert systems.By bridging technical performance and operational feasibility,this review aims to guide the development of next-generation intelligent EWS for resilient and adaptive coastal management.展开更多
The paper aimed to better characterize how flood impacts have changed over time in Japan.It is hypothesized that different flood impact indicators vary in their sensitivity to significant changes.To test this hypothes...The paper aimed to better characterize how flood impacts have changed over time in Japan.It is hypothesized that different flood impact indicators vary in their sensitivity to significant changes.To test this hypothesis,change-point analysis was applied to various indicators,including flood-related deaths,the ratio of deaths to total flood victims,and a newly proposed composite indicator that integrates both loss of life and property damage.The analysis revealed that while the annual number of flood victims has remained statistically unchanged during the study period,the proportion of deaths among victims has increased.Similarly,although the annual number of completely damaged houses did not show a significant change,the proportion of completely damaged houses relative to the total number of flooded houses has risen.According to the newly developed composite indicator,the overall impact of flooding in Japan has shifted upward since 2004.The value of this study lies in its novel approach of combining loss of life with property damage in trend analysis,enabling policymakers and citizens to better understand the evolving risks posed by floods.These findings not only provide policymakers with a comprehensive reference for evaluating the effectiveness of flood management measures but also help promote public participation in flood mitigation efforts.展开更多
Flooding can lead to oxygen deprivation in rapeseed,negatively affecting its growth and development and ul-timately reducing yields.Vitreoscilla hemoglobin(VHb),a bacterial hemoglobin with a high oxygen-binding affini...Flooding can lead to oxygen deprivation in rapeseed,negatively affecting its growth and development and ul-timately reducing yields.Vitreoscilla hemoglobin(VHb),a bacterial hemoglobin with a high oxygen-binding affinity,plays a key role in enhancing oxygen uptake and metabolic efficiency under low-oxygen conditions.Through genetic transformation,we overexpressed the VHb gene in rapeseed,which resulted in significant im-provements in survival rate,root length,and biomass under submerged conditions.Additionally,we observed that transgenic plants developed adventitious roots in response to submergence stress.These transgenic plants also exhibited increased activities of ethanol dehydrogenase and pyruvate decarboxylase-enzymes associated with anaerobic respiration.Our findings indicate that VHb enhances flooding tolerance in rapeseed by promoting adventitious root formation and strengthening the plant's capacity for fermentation metabolism under anaerobic conditions.展开更多
Flooding in rice fields,especially in coastal regions and low-lying river basins,causes significant devastation to crops.Rice is highly susceptible to prolonged flooding,with a drastic decline in yields if inundation ...Flooding in rice fields,especially in coastal regions and low-lying river basins,causes significant devastation to crops.Rice is highly susceptible to prolonged flooding,with a drastic decline in yields if inundation persists for more than 7 d,especially during the reproductive stage.Although the SUB1 QTL,which confers tolerance to complete submergence during the vegetative stage,has been incorporated into breeding programs,the development of alternative sources is crucial.These alternatives would broaden the genetic base,mitigate the influence of the genomic background,and extend the efficacy of SUB1 QTL to withstand longer submergence periods(up to approximately 21 d).Contemporary breeding strategies predominantly target submergence stress at the vegetative stage.However,stagnant flooding(partial submergence of vegetative parts)during the reproductive phase inflicts severe damage on the rice crop,leading to reduced yields,heightened susceptibility to pests and diseases,lodging,and inferior grain quality.The ability to tolerate stagnant flooding can be ascribed to several adaptive traits:accelerated aerenchyma formation,efficient underwater photosynthesis,reduced radial oxygen loss in submerged tissues,reinforced culms,enhanced reactive oxygen species scavenging within cells,dehydration tolerance post-flooding,and resistance to pests and diseases.A thorough investigation of the genetics underlying these traits,coupled with the integration of key alleles into elite genetic backgrounds,can significantly enhance food and income security in flood-prone rice-growing regions,particularly in coastal high-rainfall areas and low-lying river basins.This review aims to delineate an innovative breeding strategy that employs genomic,phenomic,and traditional breeding methodologies to develop rice varieties resilient to various dimensions of flooding stress at both the vegetative and reproductive stages.展开更多
China boasts abundant heavy oil resources,which is vital for its energy security.However,its heavy oil typically exhibits high viscosity,which severely hinders its flow and extraction.Enhancing heavy oil flowability i...China boasts abundant heavy oil resources,which is vital for its energy security.However,its heavy oil typically exhibits high viscosity,which severely hinders its flow and extraction.Enhancing heavy oil flowability is vital for its effective exploitation.This study independently developed a visualization experimental system and explored the mechanisms through which combined thermal flooding(a combination of heat,chemical agents and gas)enhances heavy oil flowability.Results indicate that combined thermal flooding,that is,synergistically integrating heat,chemical agents,and gas,can effectively enhance the recovery of heavy oil by improving its flowability.Its working mechanisms were explored from the aspects of thermal effects,emulsification,precursor film,profile control capacity,and CO_(2) solution and extraction effects.The emulsification was observed using a confocal laser scanning fluorescence microscope(CLSFM).Findings reveal that steam flooding can boost crude oil flowability by augmenting temperature,while a chemical system tends to produce low-viscosity oil-in-water emul-sions,thus further aiding the flow of crude oil.During CO_(2) flooding,the solvent initially reduced crude oil viscosity and formed foamy oil,followed by the pronounced component separation of the produced fluids in the later stage.This demonstrates the effectiveness of CO_(2) in viscosity reduction and component extraction.Additionally,the results of interfacial tension experiments indicate that surfactants can reduce the heavy oil's interfacial tension,fostering the formation of nano-scale precursor films.They can also thicken these films and diminish their spreading resistance,thus accelerating residual oil removal and promoting heavy oil production.This study further elaborated the mechanisms behind the combined thermal flooding's efficiency in enhancing heavy oil recovery,offering a theoretical foundation for its broader application.展开更多
The implementation of Countermeasure Techniques(CTs)in the context of Network-On-Chip(NoC)based Multiprocessor System-On-Chip(MPSoC)routers against the Flooding Denial-of-Service Attack(F-DoSA)falls under Multi-Criter...The implementation of Countermeasure Techniques(CTs)in the context of Network-On-Chip(NoC)based Multiprocessor System-On-Chip(MPSoC)routers against the Flooding Denial-of-Service Attack(F-DoSA)falls under Multi-Criteria Decision-Making(MCDM)due to the three main concerns,called:traffic variations,multiple evaluation criteria-based traffic features,and prioritization NoC routers as an alternative.In this study,we propose a comprehensive evaluation of various NoC traffic features to identify the most efficient routers under the F-DoSA scenarios.Consequently,an MCDM approach is essential to address these emerging challenges.While the recent MCDM approach has some issues,such as uncertainty,this study utilizes Fuzzy-Weighted Zero-Inconsistency(FWZIC)to estimate the criteria weight values and Fuzzy Decision by Opinion Score Method(FDOSM)for ranking the routers with fuzzy Single-valued Neutrosophic under names(SvN-FWZIC and SvN-FDOSM)to overcome the ambiguity.The results obtained by using the SvN-FWZIC method indicate that the Max packet count has the highest importance among the evaluated criteria,with a weighted score of 0.1946.In contrast,the Hop count is identified as the least significant criterion,with a weighted score of 0.1090.The remaining criteria fall within a range of intermediate importance,with enqueue time scoring 0.1845,packet count decremented and traversal index scoring 0.1262,packet count incremented scoring 0.1124,and packet count index scoring 0.1472.In terms of ranking,SvN-FDOSM has two approaches:individual and group.Both the individual and group ranking processes show that(Router 4)is the most effective router,while(Router 3)is the lowest router under F-DoSA.The sensitivity analysis provides a high stability in ranking among all 10 scenarios.This approach offers essential feedback in making proper decisions in the design of countermeasure techniques in the domain of NoC-based MPSoC.展开更多
To address the water sensitivity of conglomerate reservoirs,a series of core sensitivity tests were conducted to evaluate the effects of varying ionic content.These findings serve as a foundation for improving reservo...To address the water sensitivity of conglomerate reservoirs,a series of core sensitivity tests were conducted to evaluate the effects of varying ionic content.These findings serve as a foundation for improving reservoir fluid dynamics and optimizing the concentration of anti-swelling agents in water flooding operations.The experiments revealed a marked disparity in response between cores with differing permeabilities.In Core No.5,characterized by low permeability,a 0.5% anti-swelling agent achieved only a modest 7.47% reduction in water sensitivity.Conversely,in the higher-permeability Core No.8,a 5%anti-swelling agent significantly reduced the water sensitivity index by 44.84% while enhancing permeability.Further,two displacement strategies-gas flooding following water flooding and water flooding after gas injection-were tested to assess the potential of CO_(2)water-alternating-gas(WAG)displacement.CO_(2)injection after water flooding in Core No.5 increased oil recovery by 9.24%,though gas channeling,evidenced by a sharp rise in the gas-liquid ratio,emerged as a critical concern.In Core No.8,water flooding following gas injection failed to improve recovery,likely due to pronounced water sensitivity,reduced permeability,and the formation of dominant flow channels under high displacement pressure,which limited sweep efficiency.展开更多
Extensive research has been conducted on remaining oil in the Daqing Oilfield during high water cuts’late stage,but few studies have offered multi-level analyses from both macro and micro perspectives for remaining o...Extensive research has been conducted on remaining oil in the Daqing Oilfield during high water cuts’late stage,but few studies have offered multi-level analyses from both macro and micro perspectives for remaining oil under varying formation conditions and displacement methods.This article focuses on the remaining oil in the S,P,and G reservoirs of Daqing Oilfield by employing the frozen section analysis method on the cores from the S,P,and G oil layers.The research identifies patterns among them,revealing that the Micro Remaining Oil types in these cores primarily include pore surface thin film,corner,throat,cluster,intergranular adsorption,and particle adsorption.Among these,intergranular adsorption contains the highest amount of remaining oil(the highest proportion reaches 60%)and serves as the main target for development potential.The overall distribution pattern of the Micro Remaining Oil in the S,P,and G oil layers shows that as flooding intensity increases,the amount of free-state remaining oil gradually decreases,while bound-state remaining oil gradually increases.The study also examines eight typical coring wells for macroscopic remaining oil,finding four main types in the reservoir:interlayer difference,interlayer loss,interlayer interference,and injection-production imperfect types.Among these,the injection-production imperfect type has the highest remaining oil content and is the primary target for development potential.Analyzing the reservoir utilization status and oil flooding efficiency reveals that as water flooding intensifies,the oil displacement efficiency of the oil layer gradually decreases,while the efficiency of oil layer displacement improves.Strongly flooded cores exhibit less free-state remaining oil than weakly flooded cores,making displacement more challenging.This study aims to provide a foundation and support for the development of remaining oil in the S,P,and G oil layers.展开更多
Extensive flooding swept across large areas of Central Asia,mainly over Kazakhstan and southwestern Russia,from late March to April 2024.It was reported to be the worst flooding in the area in the past 70 years and ca...Extensive flooding swept across large areas of Central Asia,mainly over Kazakhstan and southwestern Russia,from late March to April 2024.It was reported to be the worst flooding in the area in the past 70 years and caused widespread devastation to society and infrastructure.However,the drivers of this record-breaking flood remain unexplored.Here,we show that the record-breaking floods were contributed by both long-term climate warming and interannual variability,with multiple climatic drivers at play across the synoptic to seasonal timescales.First,the heavy snowmelt in March 2024 was associated with above-normal preceding winter snow accumulation.Second,extreme rainfall was at a record-high during March 2024,in line with its increasing trend under climate warming.Third,the snowmelt and extreme rainfall in March were compounded by record-high soil moisture conditions in the preceding winter,which was a result of interannual variability and related to excessive winter rainfall over Central Asia.As climate warming continues,the interplay between the increasing trend of extreme rainfall,interannual variations in soil moisture pre-conditions,as well as shifting timing and magnitudes of spring snowmelt,will further increase and complicate spring flooding risks.This is a growing and widespread challenge for the mid-to high-latitude regions.展开更多
Oilfields worldwide are increasingly grappling with challenges such as early water breakthrough and high water production,yet direct,targeted solutions remain elusive.In recent years,chemical flooding techniques desig...Oilfields worldwide are increasingly grappling with challenges such as early water breakthrough and high water production,yet direct,targeted solutions remain elusive.In recent years,chemical flooding techniques designed for tertiary oil recovery have garnered significant attention,with microgel flooding emerging as a particularly prominent area of research.Despite its promise,the complex mechanisms underlying microgel flooding have been rarely investigated numerically.This study aims to address these gaps by characterizing the distribution of microgel concentration and viscosity within different pore structures.To enhance the accuracy of these characterizations,the viscosity of microgels is adjusted to account for the shear effects induced by flow rate and the swelling effects driven by salinity variations.The absolute permeability of the rock and the relative permeability of both oil and microgel are also analyzed to elucidate the mechanisms of microgel flooding.Additionally,a connectivity model is employed to achieve a quantitative representation of fluid flow capacity.The proposed model is validated through conceptual examples and applied to real oilfield blocks,demonstrating its accuracy and practical applicability.展开更多
This paper introduces a robust Distributed Denial-of-Service attack detection framework tailored for Software-Defined Networking based Internet of Things environments,built upon a novel,syntheticmulti-vector dataset g...This paper introduces a robust Distributed Denial-of-Service attack detection framework tailored for Software-Defined Networking based Internet of Things environments,built upon a novel,syntheticmulti-vector dataset generated in a Mininet-Ryu testbed using real-time flow-based labeling.The proposed model is based on the XGBoost algorithm,optimized with Principal Component Analysis for dimensionality reduction,utilizing lightweight flowlevel features extracted from Open Flow statistics to classify attacks across critical IoT protocols including TCP,UDP,HTTP,MQTT,and CoAP.The model employs lightweight flow-level features extracted from Open Flow statistics to ensure low computational overhead and fast processing.Performance was rigorously evaluated using key metrics,including Accuracy,Precision,Recall,F1-Score,False Alarm Rate,AUC-ROC,and Detection Time.Experimental results demonstrate the model’s high performance,achieving an accuracy of 98.93%and a low FAR of 0.86%,with a rapid median detection time of 1.02 s.This efficiency validates its superiority in meeting critical Key Performance Indicators,such as Latency and high Throughput,necessary for time-sensitive SDN-IoT systems.Furthermore,the model’s robustness and statistically significant outperformance against baseline models such as Random Forest,k-Nearest Neighbors,and Gradient Boosting Machine,validating through statistical tests using Wilcoxon signed-rank test and confirmed via successful deployment in a real SDN testbed for live traffic detection and mitigation.展开更多
Urban flooding in low-lying coastal regions(LCRs)is intensifying due to climate change and sea-level rise;however,the complex interplay of hydrological,climatic,and anthropogenic drivers remains poorly understood.This...Urban flooding in low-lying coastal regions(LCRs)is intensifying due to climate change and sea-level rise;however,the complex interplay of hydrological,climatic,and anthropogenic drivers remains poorly understood.This study investigates the specific meteo-hydrological factors linking climate-induced changes and human activities to the urban flooding event in My Tho City,a vulnerable coastal city in Vietnam's Tien Giang Province,from February 9 to 12,2024.Analyzing historical meteo-hydrological data(rainfall,monsoon winds,river discharge,and water levels),we examined the contributing factors.Our findings reveal that the flooding was predominantly driven by the combination of high astronomical tidal levels and significant water surges.These surges were amplified by northeast monsoon circulation.This situation was compounded by critically low Mekong River discharge during the dry season,which enhanced the inland penetration of tidal effects.Rainfall during the period was minimal and did not contribute significantly.We utilized a filtering technique to differentiate between astronomical tides and non-tidal surges in the water level data.These results provide empirical evidence demonstrating that climate-driven sea-level influences(manifesting as high tides and surges)and anthropogenic alterations to river flow governed the urban flooding dynamics.The study underscores the urgent need for integrated adaptation solutions addressing the complex land-ocean interactions, particularly in the context ofclimate change and relative sea-level rise.展开更多
基金Supported by the Major Science and Technology Program for Water Pollution Control and Treatment(2012ZX07103-0042012ZX07103-003-03)~~
文摘Organic matter (OM), total nitrogen (TN), organic phosphorous (OP) and total phosphorous (TP)content of soil in northwest water-level fluctuating zone (WLFZ) of Lake Chaohu under natural and different artificial conditions were ana- lyzed to study the variation of OM, TN, OP and TP. It showed: Flooding and air- drying help to increase soil OM content in study area. Process of flooding and air- drying is conducive to soil adsorption of nitrogen and it can enhance spatial hetero- geneity of soil OM, TN, OP, process of flooding and air-drying also can reduce the difference of TP contents among different points. Riprap embankment is not con- ducive to maintaining soil organic matter under flooded conditions, emergent plants are conducive to maintaining soil organic matter under flooded conditions. Soil with high nitrogen content will release nitrogen to overlying water under flooded condi- tions. Under drying after flooding conditions, demand for phosphorus of vegetation growth will reduce TP content in soil, bare area will enrich phosphorus, when the next flood cover up a greater release of phosphorus will happen
基金supported by the National Key Research and Development Program of China(Grant No.2023YFD2301300)the National Rice Industry Technology System,China(Grant No.CARS-01).
文摘Flooding stress is a major adverse condition during the emergence period of direct-seeded rice.This study investigated the use of wood vinegar as a seed soaking treatment to enhance rice seedling rates under flooding stress,exploring both the methodology and physiological mechanisms involved.The optimal seed soaking concentration was determined through a gradient experiment,followed by a multi-cultivar validation test.The physiological mechanism of wood vinegar soaking on seedling emergence was analyzed by measuring the electrical conductivity of the flooding water,the changes in starch and soluble sugar contents in the grains and sprouts,and the dynamics ofα-amylase activity and antioxidant-related enzyme activities in the sprouts.The results showed that soaking rice seeds in a wood vinegar solution at a low concentration significantly enhanced the emergence of rice seedlings under flooding conditions,with a 100-fold dilution having the most pronounced effect,increasing seedling rates by 50.6%-60.0%.Further analysis indicated that wood vinegar treatment enhanced seedling establishment by inducing a significant increase inα-amylase activity,leading to a 74.9%-213.6%increase in soluble sugar content in the sprouts during 2-8 d after flooding stress compared with the control.Additionally,the treatment increased superoxide dismutase and peroxidase activities in the sprouts,mitigating lipid peroxidation of the cell membranes,and notably lower water electrical conductivity was observed in wood vinegar-treated seeds compared with the control.In conclusion,soaking rice seeds in a 100-fold diluted wood vinegar solution improves rice seedling rates under flooding stress by mitigating oxidative damage and maintaining energy supply.This approach is valuable for developing cost-effective seed treatment technologies and offering novel strategies to improve seedling rates and uniformity of direct-seeded rice under flooding conditions.
文摘[Objective]Surface water flooding is caused by heavy rainfall,which has been the main type of flooding in many cities across the world.Real urban environments are highly complex,and there are numerous parameters influencing the rainfall-runoff processes,such as road width,orientation and building coverage.The main objective is to perform a parametric study concerning the rainfall-runoff processes in complex urban environments,in order to gain a better understanding of the impact of urban characteristics on the surface runoff.[Methods]Realistic urban layouts are generated by means of procedural modelling software,which parameterises the urban configurations using 11 independent variables,including the averaged street length,street orientation,street curvature,major street width,minor street width,park coverage,etc.A shock-capturing TVD MacCormack shallow water equations solver is used to undertake a large number of computational simulations regarding the rainfall-runoff processes over realistic urban layouts.The dominating urban parameters that influence the time of concentration is unveiled,which characterises the timescale of the flood formation.[Results]In order to generalise the research outcomes,the obtained hydrographs at the outlet of the catchment are normalised so that they are independent of the catchment area,slope or rainfall intensity.The dimensionless time of concentration is thus only the functions of 12 independent parameters,including 11 parameters that governing the urban layouts and the Manning roughness coefficient of the ground.A sensitivity analysis,based on the multiple linear regression method,is performed on the 2,994 simulation cases to quantify the influence of each parameter.[Conclusion]The results show that the ground roughness and the building coverage ratio are the two most important factors that influence the urban flood formation.Their influences on the dimensionless timescale of the urban catchments’response to rainfall are quantified by empirical formulae.The research findings can provide useful guidelines for the design of future flood-resilient urban environments and the improvement of existing drainage systems in cities.
基金the support of the National Natural Science Foundation of China(No.42107247)the National Key Research and Development Project(No.2022YFD1901605)+1 种基金the Natural Science Foundation of Sichuan Province(Nos.2025YFHZ0142 and 2024NSFSC0800)the Tobacco Science Foundation of Sichuan Province(No.SCYC202407)。
文摘Soil microorganisms and labile soil organic carbon(SOC)fractions are essential factors affecting greenhouse gas(GHG)emissions in paddy fields.However,the effects of labile SOC fractions and microorganisms on GHG emissions from flooding to drying after organic fertilizer replacing for chemical fertilizer remain unclear.Here,a long-term experiment was conducted with four treatments:chemical fertilization only(control),organic fertilizer substituting 25%of chemical N fertilizer(NM1),50%of chemical N fertilizer(NM2),and NM2combined with crop straw(NMS).GHG emissions were monitored,and soil samples were collected to determine labile SOC fractions and microorganisms.Results revealed the GHG emissions in the NM2 significantly increased by 196.88%from flooding to drying,mainly due to the higher CO_(2) emissions.The GHG emissions per kg of C input in NMS was the lowest with the value of 9.17.From flooding to drying,organic fertilizer application significantly increased the readily oxidizable organic carbon(ROC)contents and C lability;the NM2 and NMS dramatically increased the SOC and non-readily oxidizable organic carbon(NROC).The bacterial communities showed significant differences among different treatments in the flooding,while the significant difference was only found between the NMS and other treatments in the drying.From flooding to drying,changing soil moisture conditions causes C fractions and microbial communities to jointly affect carbon emissions,and the NMS promoted carbon sequestration and mitigated GHG emissions.Our findings highlight the importance of the labile SOC fractions and microorganisms linked to GHG emissions in paddy fields.
基金supported by the National Natural Science Foundation of China(No.42072211)the National Natural Science Foundation of China(No.42401048)the Third Xinjiang Scientific Expedition and Research Program(No.2021xjkk0302)。
文摘The Taklimakan Desert,located in the heart of central Asia,covers approximately 330000 km^(2),making it China's largest desert and the world's second-largest shifting desert(Dong et al.,2024).With an average annual precipitation of less than 100 mm and evaporation rates ranging from 2000 to 3000 mm(Yang et al.,2020),it is recognized as one of the driest regions on Earth,often referred to as the“sea of death”.
基金supported by the National Natural Science Foundation of China(52104049)the Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology(BYESS2023262)。
文摘Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.
文摘Floods and storm surges pose significant threats to coastal regions worldwide,demanding timely and accurate early warning systems(EWS)for disaster preparedness.Traditional numerical and statistical methods often fall short in capturing complex,nonlinear,and real-time environmental dynamics.In recent years,machine learning(ML)and deep learning(DL)techniques have emerged as promising alternatives for enhancing the accuracy,speed,and scalability of EWS.This review critically evaluates the evolution of ML models—such as Artificial Neural Networks(ANN),Convolutional Neural Networks(CNN),and Long Short-Term Memory(LSTM)—in coastal flood prediction,highlighting their architectures,data requirements,performance metrics,and implementation challenges.A unique contribution of this work is the synthesis of real-time deployment challenges including latency,edge-cloud tradeoffs,and policy-level integration,areas often overlooked in prior literature.Furthermore,the review presents a comparative framework of model performance across different geographic and hydrologic settings,offering actionable insights for researchers and practitioners.Limitations of current AI-driven models,such as interpretability,data scarcity,and generalization across regions,are discussed in detail.Finally,the paper outlines future research directions including hybrid modelling,transfer learning,explainable AI,and policy-aware alert systems.By bridging technical performance and operational feasibility,this review aims to guide the development of next-generation intelligent EWS for resilient and adaptive coastal management.
文摘The paper aimed to better characterize how flood impacts have changed over time in Japan.It is hypothesized that different flood impact indicators vary in their sensitivity to significant changes.To test this hypothesis,change-point analysis was applied to various indicators,including flood-related deaths,the ratio of deaths to total flood victims,and a newly proposed composite indicator that integrates both loss of life and property damage.The analysis revealed that while the annual number of flood victims has remained statistically unchanged during the study period,the proportion of deaths among victims has increased.Similarly,although the annual number of completely damaged houses did not show a significant change,the proportion of completely damaged houses relative to the total number of flooded houses has risen.According to the newly developed composite indicator,the overall impact of flooding in Japan has shifted upward since 2004.The value of this study lies in its novel approach of combining loss of life with property damage in trend analysis,enabling policymakers and citizens to better understand the evolving risks posed by floods.These findings not only provide policymakers with a comprehensive reference for evaluating the effectiveness of flood management measures but also help promote public participation in flood mitigation efforts.
基金supported by National Key Research and Development Program of China(2023YFD1201403)The Science and Technology Innovation Program of Hunan Province(2023RC1077)+2 种基金Key Research and Development Projects of Hunan Provincial(2023NK2012)Hunan Provincial Science and Technology Talent Promotion Project(2023 TJ-Z09)The Hunan Agricultural Science and Technology Innovation Fund Project(2024CX096).
文摘Flooding can lead to oxygen deprivation in rapeseed,negatively affecting its growth and development and ul-timately reducing yields.Vitreoscilla hemoglobin(VHb),a bacterial hemoglobin with a high oxygen-binding affinity,plays a key role in enhancing oxygen uptake and metabolic efficiency under low-oxygen conditions.Through genetic transformation,we overexpressed the VHb gene in rapeseed,which resulted in significant im-provements in survival rate,root length,and biomass under submerged conditions.Additionally,we observed that transgenic plants developed adventitious roots in response to submergence stress.These transgenic plants also exhibited increased activities of ethanol dehydrogenase and pyruvate decarboxylase-enzymes associated with anaerobic respiration.Our findings indicate that VHb enhances flooding tolerance in rapeseed by promoting adventitious root formation and strengthening the plant's capacity for fermentation metabolism under anaerobic conditions.
基金the University Grants Commission(UGC),Government of India for the UGC-Non-NET Fellowship during the PhD degree program(Grant No.R/Dev/IX-Sch/BHU-Res-Sch/2022-23/51137).
文摘Flooding in rice fields,especially in coastal regions and low-lying river basins,causes significant devastation to crops.Rice is highly susceptible to prolonged flooding,with a drastic decline in yields if inundation persists for more than 7 d,especially during the reproductive stage.Although the SUB1 QTL,which confers tolerance to complete submergence during the vegetative stage,has been incorporated into breeding programs,the development of alternative sources is crucial.These alternatives would broaden the genetic base,mitigate the influence of the genomic background,and extend the efficacy of SUB1 QTL to withstand longer submergence periods(up to approximately 21 d).Contemporary breeding strategies predominantly target submergence stress at the vegetative stage.However,stagnant flooding(partial submergence of vegetative parts)during the reproductive phase inflicts severe damage on the rice crop,leading to reduced yields,heightened susceptibility to pests and diseases,lodging,and inferior grain quality.The ability to tolerate stagnant flooding can be ascribed to several adaptive traits:accelerated aerenchyma formation,efficient underwater photosynthesis,reduced radial oxygen loss in submerged tissues,reinforced culms,enhanced reactive oxygen species scavenging within cells,dehydration tolerance post-flooding,and resistance to pests and diseases.A thorough investigation of the genetics underlying these traits,coupled with the integration of key alleles into elite genetic backgrounds,can significantly enhance food and income security in flood-prone rice-growing regions,particularly in coastal high-rainfall areas and low-lying river basins.This review aims to delineate an innovative breeding strategy that employs genomic,phenomic,and traditional breeding methodologies to develop rice varieties resilient to various dimensions of flooding stress at both the vegetative and reproductive stages.
基金The authors thank the National Natural Science Foundation of China(Grant No.U20B6003)for their financial support to carry out this research.
文摘China boasts abundant heavy oil resources,which is vital for its energy security.However,its heavy oil typically exhibits high viscosity,which severely hinders its flow and extraction.Enhancing heavy oil flowability is vital for its effective exploitation.This study independently developed a visualization experimental system and explored the mechanisms through which combined thermal flooding(a combination of heat,chemical agents and gas)enhances heavy oil flowability.Results indicate that combined thermal flooding,that is,synergistically integrating heat,chemical agents,and gas,can effectively enhance the recovery of heavy oil by improving its flowability.Its working mechanisms were explored from the aspects of thermal effects,emulsification,precursor film,profile control capacity,and CO_(2) solution and extraction effects.The emulsification was observed using a confocal laser scanning fluorescence microscope(CLSFM).Findings reveal that steam flooding can boost crude oil flowability by augmenting temperature,while a chemical system tends to produce low-viscosity oil-in-water emul-sions,thus further aiding the flow of crude oil.During CO_(2) flooding,the solvent initially reduced crude oil viscosity and formed foamy oil,followed by the pronounced component separation of the produced fluids in the later stage.This demonstrates the effectiveness of CO_(2) in viscosity reduction and component extraction.Additionally,the results of interfacial tension experiments indicate that surfactants can reduce the heavy oil's interfacial tension,fostering the formation of nano-scale precursor films.They can also thicken these films and diminish their spreading resistance,thus accelerating residual oil removal and promoting heavy oil production.This study further elaborated the mechanisms behind the combined thermal flooding's efficiency in enhancing heavy oil recovery,offering a theoretical foundation for its broader application.
文摘The implementation of Countermeasure Techniques(CTs)in the context of Network-On-Chip(NoC)based Multiprocessor System-On-Chip(MPSoC)routers against the Flooding Denial-of-Service Attack(F-DoSA)falls under Multi-Criteria Decision-Making(MCDM)due to the three main concerns,called:traffic variations,multiple evaluation criteria-based traffic features,and prioritization NoC routers as an alternative.In this study,we propose a comprehensive evaluation of various NoC traffic features to identify the most efficient routers under the F-DoSA scenarios.Consequently,an MCDM approach is essential to address these emerging challenges.While the recent MCDM approach has some issues,such as uncertainty,this study utilizes Fuzzy-Weighted Zero-Inconsistency(FWZIC)to estimate the criteria weight values and Fuzzy Decision by Opinion Score Method(FDOSM)for ranking the routers with fuzzy Single-valued Neutrosophic under names(SvN-FWZIC and SvN-FDOSM)to overcome the ambiguity.The results obtained by using the SvN-FWZIC method indicate that the Max packet count has the highest importance among the evaluated criteria,with a weighted score of 0.1946.In contrast,the Hop count is identified as the least significant criterion,with a weighted score of 0.1090.The remaining criteria fall within a range of intermediate importance,with enqueue time scoring 0.1845,packet count decremented and traversal index scoring 0.1262,packet count incremented scoring 0.1124,and packet count index scoring 0.1472.In terms of ranking,SvN-FDOSM has two approaches:individual and group.Both the individual and group ranking processes show that(Router 4)is the most effective router,while(Router 3)is the lowest router under F-DoSA.The sensitivity analysis provides a high stability in ranking among all 10 scenarios.This approach offers essential feedback in making proper decisions in the design of countermeasure techniques in the domain of NoC-based MPSoC.
文摘To address the water sensitivity of conglomerate reservoirs,a series of core sensitivity tests were conducted to evaluate the effects of varying ionic content.These findings serve as a foundation for improving reservoir fluid dynamics and optimizing the concentration of anti-swelling agents in water flooding operations.The experiments revealed a marked disparity in response between cores with differing permeabilities.In Core No.5,characterized by low permeability,a 0.5% anti-swelling agent achieved only a modest 7.47% reduction in water sensitivity.Conversely,in the higher-permeability Core No.8,a 5%anti-swelling agent significantly reduced the water sensitivity index by 44.84% while enhancing permeability.Further,two displacement strategies-gas flooding following water flooding and water flooding after gas injection-were tested to assess the potential of CO_(2)water-alternating-gas(WAG)displacement.CO_(2)injection after water flooding in Core No.5 increased oil recovery by 9.24%,though gas channeling,evidenced by a sharp rise in the gas-liquid ratio,emerged as a critical concern.In Core No.8,water flooding following gas injection failed to improve recovery,likely due to pronounced water sensitivity,reduced permeability,and the formation of dominant flow channels under high displacement pressure,which limited sweep efficiency.
文摘Extensive research has been conducted on remaining oil in the Daqing Oilfield during high water cuts’late stage,but few studies have offered multi-level analyses from both macro and micro perspectives for remaining oil under varying formation conditions and displacement methods.This article focuses on the remaining oil in the S,P,and G reservoirs of Daqing Oilfield by employing the frozen section analysis method on the cores from the S,P,and G oil layers.The research identifies patterns among them,revealing that the Micro Remaining Oil types in these cores primarily include pore surface thin film,corner,throat,cluster,intergranular adsorption,and particle adsorption.Among these,intergranular adsorption contains the highest amount of remaining oil(the highest proportion reaches 60%)and serves as the main target for development potential.The overall distribution pattern of the Micro Remaining Oil in the S,P,and G oil layers shows that as flooding intensity increases,the amount of free-state remaining oil gradually decreases,while bound-state remaining oil gradually increases.The study also examines eight typical coring wells for macroscopic remaining oil,finding four main types in the reservoir:interlayer difference,interlayer loss,interlayer interference,and injection-production imperfect types.Among these,the injection-production imperfect type has the highest remaining oil content and is the primary target for development potential.Analyzing the reservoir utilization status and oil flooding efficiency reveals that as water flooding intensifies,the oil displacement efficiency of the oil layer gradually decreases,while the efficiency of oil layer displacement improves.Strongly flooded cores exhibit less free-state remaining oil than weakly flooded cores,making displacement more challenging.This study aims to provide a foundation and support for the development of remaining oil in the S,P,and G oil layers.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42422502,42275038)the China Meteorological Administration Climate Change Special Program(Grant No.QBZ202306)。
文摘Extensive flooding swept across large areas of Central Asia,mainly over Kazakhstan and southwestern Russia,from late March to April 2024.It was reported to be the worst flooding in the area in the past 70 years and caused widespread devastation to society and infrastructure.However,the drivers of this record-breaking flood remain unexplored.Here,we show that the record-breaking floods were contributed by both long-term climate warming and interannual variability,with multiple climatic drivers at play across the synoptic to seasonal timescales.First,the heavy snowmelt in March 2024 was associated with above-normal preceding winter snow accumulation.Second,extreme rainfall was at a record-high during March 2024,in line with its increasing trend under climate warming.Third,the snowmelt and extreme rainfall in March were compounded by record-high soil moisture conditions in the preceding winter,which was a result of interannual variability and related to excessive winter rainfall over Central Asia.As climate warming continues,the interplay between the increasing trend of extreme rainfall,interannual variations in soil moisture pre-conditions,as well as shifting timing and magnitudes of spring snowmelt,will further increase and complicate spring flooding risks.This is a growing and widespread challenge for the mid-to high-latitude regions.
基金supported by the National Natural Science Foundation project“Micro-Scale Effect of Oil-Gas Flow and the Mechanism of Enhancing Shale Oil Recovery by Natural Gas Injection”(No.52074317)。
文摘Oilfields worldwide are increasingly grappling with challenges such as early water breakthrough and high water production,yet direct,targeted solutions remain elusive.In recent years,chemical flooding techniques designed for tertiary oil recovery have garnered significant attention,with microgel flooding emerging as a particularly prominent area of research.Despite its promise,the complex mechanisms underlying microgel flooding have been rarely investigated numerically.This study aims to address these gaps by characterizing the distribution of microgel concentration and viscosity within different pore structures.To enhance the accuracy of these characterizations,the viscosity of microgels is adjusted to account for the shear effects induced by flow rate and the swelling effects driven by salinity variations.The absolute permeability of the rock and the relative permeability of both oil and microgel are also analyzed to elucidate the mechanisms of microgel flooding.Additionally,a connectivity model is employed to achieve a quantitative representation of fluid flow capacity.The proposed model is validated through conceptual examples and applied to real oilfield blocks,demonstrating its accuracy and practical applicability.
文摘This paper introduces a robust Distributed Denial-of-Service attack detection framework tailored for Software-Defined Networking based Internet of Things environments,built upon a novel,syntheticmulti-vector dataset generated in a Mininet-Ryu testbed using real-time flow-based labeling.The proposed model is based on the XGBoost algorithm,optimized with Principal Component Analysis for dimensionality reduction,utilizing lightweight flowlevel features extracted from Open Flow statistics to classify attacks across critical IoT protocols including TCP,UDP,HTTP,MQTT,and CoAP.The model employs lightweight flow-level features extracted from Open Flow statistics to ensure low computational overhead and fast processing.Performance was rigorously evaluated using key metrics,including Accuracy,Precision,Recall,F1-Score,False Alarm Rate,AUC-ROC,and Detection Time.Experimental results demonstrate the model’s high performance,achieving an accuracy of 98.93%and a low FAR of 0.86%,with a rapid median detection time of 1.02 s.This efficiency validates its superiority in meeting critical Key Performance Indicators,such as Latency and high Throughput,necessary for time-sensitive SDN-IoT systems.Furthermore,the model’s robustness and statistically significant outperformance against baseline models such as Random Forest,k-Nearest Neighbors,and Gradient Boosting Machine,validating through statistical tests using Wilcoxon signed-rank test and confirmed via successful deployment in a real SDN testbed for live traffic detection and mitigation.
基金supported by the Vietnam National University,Ho Chi Minh City(VNU-HCM)project entitled“Identifying and quantifying drivers causing water level fluctuations in the Vietnamese Mekong Delta”grant number[B2024-18-01].
文摘Urban flooding in low-lying coastal regions(LCRs)is intensifying due to climate change and sea-level rise;however,the complex interplay of hydrological,climatic,and anthropogenic drivers remains poorly understood.This study investigates the specific meteo-hydrological factors linking climate-induced changes and human activities to the urban flooding event in My Tho City,a vulnerable coastal city in Vietnam's Tien Giang Province,from February 9 to 12,2024.Analyzing historical meteo-hydrological data(rainfall,monsoon winds,river discharge,and water levels),we examined the contributing factors.Our findings reveal that the flooding was predominantly driven by the combination of high astronomical tidal levels and significant water surges.These surges were amplified by northeast monsoon circulation.This situation was compounded by critically low Mekong River discharge during the dry season,which enhanced the inland penetration of tidal effects.Rainfall during the period was minimal and did not contribute significantly.We utilized a filtering technique to differentiate between astronomical tides and non-tidal surges in the water level data.These results provide empirical evidence demonstrating that climate-driven sea-level influences(manifesting as high tides and surges)and anthropogenic alterations to river flow governed the urban flooding dynamics.The study underscores the urgent need for integrated adaptation solutions addressing the complex land-ocean interactions, particularly in the context ofclimate change and relative sea-level rise.