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Numerical investigation of hydro-morphodynamic characteristics of a cascading failure of landslide dams

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Journal of Mountain Science 2024年第6期21卷 1868-1885页

作者： ZHONG Qiming CHEN Lingchun MEI Shengyao SHAN Yibo WU Hao ZHAO Kunpeng department of Geotechnical Engineering Nanjing Hydraulic Research InstituteNanjing 210024China National Key Laboratory of Water Disaster Prevention Nanjing 210098China Key Laboratory of Reservoir and Dam Safety of the Ministry of Water Resources Nanjing 210029China

A cascading failure of landslide dams caused by strong earthquakes or torrential rains in mountainous river valleys can pose great threats to people’s lives,properties,and *** this study,based on the three-dimensional Reynoldsaveraged Navier-Stokes equations(RANS),the renormalization group(RNG)k-εturbulence model,suspended and bed load transport equations,and the instability discriminant formula of dam breach side slope,and the explicit finite volume method(FVM),a detailed numerical simulation model for calculating the hydro-morphodynamic characteristics of cascading dam breach process has been *** developed numerical model can simulate the breach hydrograph and the dam breach morphology evolution during the cascading failure process of landslide dams.A model test of the breaches of two cascading landslide dams has been used as the validation *** comparison of the calculated and measured results indicates that the breach hydrograph and the breach morphology evolution process of the upstream and downstream dams are generally consistent with each other,and the relative errors of the key breaching parameters,i.e.,the peak breach flow and the time to peak of each dam,are less than±5%.Further,the comparison of the breach hydrographs of the upstream and downstream dams shows that there is an amplification effect of the breach flood on the cascading landslide dam *** key parameters,i.e.,the distance between the upstream and the downstream dams,the river channel slope,and the downstream dam height,have been used to study the flood amplification *** parameter sensitivity analyses show that the peak breach flow at the downstream dam decreases with increasing distance between the upstream and the downstream dams,and the downstream dam ***,the peak breach flow at the downstream dam first increases and then decreases with steepening of the river channel *** the flood caused by the upstream dam failure flows to the

关键词： Cascading landslide dams Cascading dam failure process Detailed numerical simulation model Flood amplification effect Parameter sensitivity analyses

Accounting for Quadratic and Cubic Invariants in Continuum Mechanics–An Overview

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Fluid Dynamics & Materials Processing 2024年第9期20卷 1925-1939页

作者： Artur V.Dmitrenko Vladislav M.Ovsyannikov department of Physics National Research Nuclear University(MEPhI)Kashirskoye Shosse 31Moscow115409Russian Federation department of Thermal Engineering and department of Waterways Ports and Hydraulic StructuresRussian University of Transport(MIIT)Obraztsova Street 9Moscow127994Russian Federation

The differential equations of continuum mechanics are the basis of an uncountable variety of phenomena and technological processes in fluid-dynamics and related *** equations contain derivatives of the first order with respect to *** derivation of the equations of continuum mechanics uses the limit transitions of the tendency of the volume increment and the time increment to *** are used to derive the wave *** differential wave equation is second order in ***,increments of volume and increments of time in continuum mechanics should be considered as small but finite quantities for problems of wave *** is important for calculating the generation of sound waves and water hammer ***,the Euler continuity equation with finite time increments is of *** finiteness of the time increment makes it possible to take into account the quadratic and cubic invariants of the strain rate *** is a new branch in *** and cubic invariants will be used in differential wave equations of the second and third order in time.

关键词： Quadratic invariant cubic invariant continuity equation generation of periodic waves N.E.Zhukovsky’s hydraulic shock turbulence

堆石混凝土坝概述及下一代混凝土坝施工技术展望

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Engineering 2024年第1期32卷 99-105页

作者： Feng Jin Duruo Huang Michel Lino Hu Zhou department of hydraulic Engineering Tsinghua UniversityBeijing 100084China ISL Ingénierie International Commission on Large DamsParis 75016France

Over the past few decades,one of the most significant advances in dam construction has been the inven-tion of the rock-filled concrete(RFC)dam,which is constructed by pouring high-performance self-compacting concrete(HSCC)to fill the voids in preplaced large *** innovative use of large rocks in dam construction provides engineers with a material that requires less cement consumption and hydration heat while enhancing construction efficiency and environmental ***,two fundamental scientific issues related to RFC need to be addressed:namely,the pouring compactness and the effect of large rocks on the mechanical and physical properties of *** article provides a timely review of fundamental research and innovations in the design,construction,and quality control of *** for next-generation concrete dams are discussed from the perspectives of envi-ronmental friendliness,intrinsic safety,and labor savings.

关键词： Rock-filled concrete dam Pouring compactness Effect of large rocks Intelligent quality control Unmanned dam construction

Survey on digital twins for Internet of Vehicles:Fundamentals,challenges,and opportunities

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Digital Communications and Networks 2024年第2期10卷 237-247页

作者： Jiajie Guo Muhammad Bilal Yuying Qiu Cheng Qian Xiaolong Xu Kim-Kwang Raymond Choo School of Computer and Software Nanjing University of Information Science and TechnologyNanjing210044China department of Computer Engineering Hankuk University of Foreign StudiesGyeonggi-do17035South Korea Jiangsu hydraulic Research Institute Nanjing210044China department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX78249-0631USA

As autonomous vehicles and the other supporting infrastructures(e.g.,smart cities and intelligent transportation systems)become more commonplace,the Internet of Vehicles(IoV)is getting increasingly *** have been attempts to utilize Digital Twins(DTs)to facilitate the design,evaluation,and deployment of IoV-based systems,for example by supporting high-fidelity modeling,real-time monitoring,and advanced predictive ***,the literature review undertaken in this paper suggests that integrating DTs into IoV-based system design and deployment remains an understudied *** addition,this paper explains how DTs can benefit IoV system designers and implementers,as well as describes several challenges and opportunities for future researchers.

关键词： Internet of vehicles Digital twin Simulation Traffic systems

Spatial correlations in time and frequency domains between chlorophyll-a concentration and environmental factors in the Bohai Sea

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Journal of Oceanology and Limnology 2024年第4期42卷 1143-1156页

作者： Wan XU Di MU Zhenteng YANG Dekui YUAN department of Mechanics Tianjin UniversityTianjin 300350China Engineering Research Center of Seawater Utilization of Ministry of Education School of Chemical Engineering and TechnologyHebei University of TechnologyTianjin 300130China State Key Laboratory of hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Based on the reconstructed MODIS data and ECMWF reanalysis data from 2003 to 2021,spatial correlations between chlorophyll a(Chl a)and sea surface temperature(SST),photosynthetically available radiation(PAR),aerosol optical thickness(AOT),and wind speed(WS)in the Bohai Sea were analyzed from the perspective of time domain and frequency *** indicate that the frequency domain analysis was more conducive to revealing the correlations between Chl a and environmental *** spatial pattern of time-domain correlations was similar to the isobaths of the Bohai Sea,which was positive in shallow waters and negative in deep waters for SST,PAR,and AOT,and was reversed for ***-domain correlations were obtained by performing Fourier Transform and were higher than correlations in time *** spatial distributions indicated that the effects of SST and PAR on Chl a were greater than AOT and WS in the Bohai ***,cross-spectrum analysis was applied to explore the response relationships.A depth-dependent pattern was shown in correlations and time lags,indicating that the influential mechanism of environmental factors on Chl-a concentration is related to seawater depth.

关键词： chlorophyll a(Chl a) frequency domain spatial correlation Bohai Sea

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

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Natural Resources 2024年第1期15卷 1-16页

作者： Abdou Khafor Ndiaye Falilou Coundoul Abdoulaye Deme Antonina Torrens Armengol Abdoulaye Senghor UFR of Applied Sciences and Technology Gaston Berger University of Senegal Saint-Louis Senegal Polytechnic Institute of Saint-Louis (IPSL) Gaston Berger University of Saint-Louis Saint-Louis Senegal department of Biology Healthcare and Environment Faculty of Pharmacy and Food Sciences University of Barcelona Barcelona Spain sanitation department Ministry in Charge of Sanitation Dakar Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

关键词： Constructed Wetlands Horizontal Flow Reed Beds Wastewater Treatment Phragmites and Typha Plants Physicochemical Pollutant Removal Microbiological Indicators Fecal Coliforms and Helminth Eggs Water Quality Improvement Senegal Water Reuse Standards Sustainable Water Management Agricultural Irrigation Reuse Nutrient Removal Efficiency Environmental Engineering Ecological sanitation Systems

Effect of the sloping seabed on 3D soil-spudcan interaction using a material point-finite element(MPM-FEM)model

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1436-1454页

作者： Zhengda Lei Guangtian Zeng Huaihui Ren Bisheng Wu Yuxin Jie State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijingChina Key Laboratory of the Hydrosphere Sciences of the Ministry of Water Resources BeijingChina Institute of Ocean Engineering Tsinghua UniversityBeijingChina Longyuan (Beijing) Wind Power Engineering Technology Co. Ltd.BeijingChina

The sloping seabed affects the bearing capacity and failure mechanism of soil,which may compromise the stability and safety of offshore structures such as jack-up *** paper employs a coupled model combining the material point method and finite element method(MPM-FEM)to analyze the impact of sloping seabeds on the three-dimensional soil-spudcan *** MPM-FEM model implements the B¯approach to solve the challenge of volumetric locking due to the incompressibility constraints imposed by yield *** is validated against the centrifuge *** effects of sloping seabeds on penetration resistance,soil flow pattern,lateral response,stress distribution,and failure mechanism are *** soil mainly undergoes overall failure when the ratio of penetration depth to spudcan diameter(i.e.D P/D)is between 0 and *** the slope angle increases,the soil on the side of lower slope is expelled further,resulting in an asymmetric stress distribution and a larger horizontal sliding force of *** D P/D increases to 0.75,the soil transitions to localized plastic flow failure,and the range of soil flow affected by the spudcan penetration *** results show that,when the slope angle increases,the lateral displacement and stress distribution on the lower slope of a sloping seabed is significantly larger than that of a horizontal seabed,impacting the spudcan and surrounding soil *** study suggests that the seabed slope significantly affects the range of soil flow and failure at shallow penetration,indicating that the slope angle should be taken into account in the design and installation of offshore jack-up rigs,particularly in areas with sloping seabeds.

关键词： Soil-spudcan interaction Centrifuge tests MPM-FEM model B—approach Sloping seabeds Offshore structures

Molecular characterization of an outbreak-involved Bacillus anthracis strain confirms the spillover of anthrax from West Africa

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Infectious Diseases of Poverty 2024年第1期13卷 93-94页

作者： Shuchao Wang Roland Suluku Mohamed B.Jalloh Ahmed F.Samba Baogui Jiang Yubiao Xie Doris Harding Mengyao Zhang Foday Sahr Mahmud E.Sesay James S.Squire Mohamed A.Vandi Moinina N.Kallon Shoufeng Zhang Rongliang Hu Yuee Zhao Zhiqiang Mi Changchun Veterinary Research Institute Chinese Academy of Agricultural Sciences Changchun China department of Animal Sciences School of Agriculture and Food Sciences Njala University Njala Sierra Leone department of Microbiology College of Medicine and Allied Health Sciences University of Sierra Leone Freetown Sierra Leone Ministry of Agriculture and Food Sciences Freetown Sierra Leone Beijing Institute of Microbiology and Epidemiology Beijing China Ministry of Health and sanitation Freetown Sierra Leone Beijing Institute of Biotechnology Beijing China

Background Anthrax,a zoonotic disease caused by the spore-forming bacterium Bacillus anthracis,remains a major global public health concern,especially in countries with limited *** Leone,a West African country historically plagued by anthrax,has almost been out of report on this disease in recent *** this study,we described a large-scale anthrax outbreak affecting both animals and humans and attempted to characterize the *** The causative agent of the animal outbreak in Port Loko District,Sierra Leone,between March and May 2022 was identified using the nanopore sequencing technique.A nationwide active surveillance was implemented from May 2022 to June 2023 to monitor the occurrence of anthrax-specific symptoms in *** cases were subsequently verified using quantitative polymerase chain ***-genome sequencing was accomplished by combining long-read and short-read sequencing *** phylogenetic analysis was performed based on the full-chromosome single nucleotide *** The outbreak in Port Loko District,Sierra Leone,led to the death of 233 animals between March 26th and May 16th,*** ruled out the initial suspicion of Anaplasma species and successfully identified *** as the causative agent of the *** a result of the government's prompt response,out of the 49 suspected human cases identifed during the one-year active surveillance,only 6 human cases tested positive,all within the frst month after the official declaration of the *** phylogenetic analysis indicated that the BaSL2022 isolate responsible for the outbreak was positioned in the ***.153 clade within the TransEuroAsian group of *** We successfully identifed a large-scale anthrax outbreak in Sierra *** causative isolate of ***,BaSL2022,phylogenetically bridged other lineages in ***.153 clade and neighboring genetic groups,***.144 and ***.148,

关键词： Molecular identification Anthrax Bacillus anthracis Sierra Leone Phylogeny Single nucleotide polymorphism

Characterization of geological uncertainties from limited boreholes using copula-based coupled Markov chains for underground construction

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Underground Space 2024年第3期16卷 94-105页

作者： Fan Wang Heng Li Gang Li Zheng-Jun You Elton J.Chen National Center of Technology Innovation for Digital Construction Huazhong University of Science and TechnologyWuhan 430074China department of Civil and hydraulic Engineering Huazhong University of Science and TechnologyWuhan 430074China department of Building and Real Estate The Hong Kong Polytechnic UniversityKowloon 999077Hong KongChina Shanghai Tunnel Engineering Co. Ltd.Shanghai 200032China Wuhan Metro Group Co.Ltd. Wuhan 430070China

This paper proposes an efficient method for quantifying the stratigraphic uncertainties and modeling the geological formations based on *** Markov chains are used to describe the soil transitions along different directions,and the transition probability matrices(TPMs)of the Markov chains are analytically expressed by *** copula expression is efficient since it can represent a large TPM by a few unknown *** to the analytical expression of the TPMs,the likelihood function of the Markov chain model is given in an explicit *** estimation of the TPMs is then re-casted as a multi-objective constrained optimization problem that aims to maximize the likelihoods of two independent Markov chains subject to a set of parameter *** the method which determines the TPMs by counting the number of transitions between soil types,the proposed method is more statistically ***,a random path sampling method is presented to avoid the directional effect problem in *** soil type at a location is inferred from its nearest known neighbors along the cardinal directions.A general form of the conditional probability,based on Pickard’s theorem and Bayes rule,is presented for the soil type *** proposed stratigraphic characterization and simulation method is applied to real borehole data collected from a construction site in Wuhan,*** is illustrated that the proposed method is accurate in prediction and does not show an inclination during simulation.

关键词： Geological stratigraphy Markov chain Transition probability matrix Statistical method Copula