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Climate Change:No Going Back

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China Today 2025年第1期74卷 42-44页

作者： ROBERT WALkER Beijing Normal University Royal Society of Arts Academy of Social Sciences in the U.k

With a commitment to reduce emissions,and its investment in green technology bringing down global costs,China is emerging as the leader in fighting climate *** knows that our world is getting *** also know *** out po... 详细信息

关键词： investment bringing fighting

Life-Cycle Bearing Capacity for Pre-Stressed T-beams Based on Full-Scale Destructive Test

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Structural Durability & Health Monitoring 2025年第1期19卷 145-166页

作者： Yushan Ye Tao Gao Liankun Wang Junjie Ma Yingchun Cai Heng Liu Xiaoge Liu China Construction Seventh Engineering Division Corp. Ltd.Zhengzhou450004China School of water Conservancy and Transportation Zhengzhou UniversityZhengzhou450001China

To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete *** on the measurement and ana-lysis of beam deﬂection,strain,and crack development under various loading levels during the research tests,combined with the veriﬁcation coefﬁcient indicators speciﬁed in the codes,the veriﬁcation coefﬁcients of bridges at different stages of damage can be *** results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test *** the complete linear elastic stage,both the deﬂection and bottom strain veriﬁcation coefﬁcients comply with the speciﬁcations,indicating a good structural load-bearing capacity no longer adheres to the code’s *** the non-linear stage,both coefﬁcients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing *** to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s speciﬁed *** strain veriﬁcation coefﬁcient sourced from the compression zone at the bottom of theﬂange is not recommended for assessing the bridge’s load-bearing capacity.

关键词： Pre-stressed T-beams whole process destructive test bearing capacity veriﬁcation coefﬁcient

Evaluating estimated sediment delivery by Revised Universal Soil Loss Equation(RUSLE)and Sediment Delivery Distributed(SEDD)in the Talar watershed,Iran

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Frontiers of Earth Science 2020年第1期14卷 50-62页

作者： Mohammad Saeid MIRAkHORLO Majid RAHIMZADEGAN Department of water Resources Faculty of Civil EngineeringK.N.Toosi University of TechnologyTehranIran

The performance of the Revised Universal Soil Loss Equation(RUSLE)as the most widely used soil erosion model is a challenging ***,the objective of this study is investigating the estimated sediment delivery by the RUSLE method and Sediment Delivery Distributed(SEDD)*** this end,the Talar watershed in Iran was selected as the study ***,700 paired sediment-discharge measurements at Valikbon and Shirgah-Talar hydrometric stations between the years 1991 and 2011 were collected and used in sediment rating *** procedures were investigated to produce the required RUSLE *** estimated soil erosion by RUSLE was evaluated using sediment rating curve data by two methods including least squares and quantile *** average annual suspended sediment load was calculated for each sub-watershed of the study area using the SEDD ***,a sediment rating curve was estimated by least squares and quantile regression methods using paired discharge-sediment *** average annual suspended sediment load values were calculated for two hydrometric stations and were further evaluated by the SEDD *** results indicated that the first considered procedure,which utilized 15-min rainfall measurements for the rainfall factor(R),and the classification method of SENTINEL-2 MSI image for the cover management factor(C),offered the best results in producing RUSLE ***,the results revealed the advantages of utilizing satellite images in producing cover management layer,which is required in the RUSLE method.

关键词： Revised Universal Soil Loss Equation(RUSLE) sediment rating curve quantile regression Geographic Information System(GIS)

Macro-mechanics and Microstructure of Nanomaterial-modified Geopolymer Concrete:A Comprehensive Review

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期 204-214页

作者：王涛范向前 GAO Changsheng QU Chiyu The National key Laboratory of water Disaster Prevention Nanjing Hydraulic Research Institute Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) School of water Conservancy and Transportation Zhengzhou University

We have described in detail the effects of nano-SiO2,nano-CaCO3,carbon nanotubes,and nano-Al2O3on geopolymer concrete from the perspectives of macro mechanics and *** existing research results show that the mechanism of nano-materials on geopolymer concrete mainly includes the filling effect,nucleation effect,and bridging effect,the appropriate amount of nano-materials can be used as fillers to reduce the porosity of geopolymer concrete,and can also react with Ca（OH）2to produce C-S-H gel,thereby improving the mechanical properties of geopolymer *** optimum content of nano-SiO2is between 1.0% and 2.0%.The optimum content of nano-CaCO3is between 2.0% and 3.0%.The optimum content of carbon nanotubes is between 0.1% and 0.2%.The optimum content of nano-Al2O3is between 1.0% and 2.0%.The main problems existing in the research and application of nanomaterial-modified geopolymer concrete are summarized,which lays a foundation for the further application of nanomaterial in geopolymer concrete.

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Evaluation of geochemical behavior and heavy metal distribution of sediments:The case study of the Tirumalairajan river estuary,southeast coast of India

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International Journal of Sediment Research 2015年第1期30卷 28-38页

作者： Senapathi VENkATRAMANAN Sang-yong CHUNG Thirunavukkarasu RAMkUMAR Gopalakrishnan GNANACHANDRASAMY Tae Hyung kIM Department of Earth & Environmental Sciences Institute of Environmental GeosciencesPukyong National University Department of Earth Sciences Annamalai University k-water Institute Korea Water Resources Corporation

The purpose of this study was to assess the chemical partitioning of selected heavy metals(Fe,Mn,Cu,Zn,Pb,Cr,Co and Ni) in 10 surface sediments at Tirumalairajan River Estuary in the southeastern coast of India.A five-step sequential extraction technique was used to assess the environmental status of heavy *** of metals were considered to be immobile due to the high availability in the residual fraction of heavy *** sediments of Tirumalairajan River estuary had not been polluted by heavy metals,and they didn’t pose any high ecological *** seasonal variations of heavy metals were slightly higher in summer than in monsoon *** analysis was also carned out to understand the associations of metals in different fractions with sand,silt,clay,organic matter,pH,salinity and other *** relationship between the Q-mode and R-mode cluster analyses was useful for identifying the pollution levels in both *** was proved that the enrichment of heavy metals was related with geogenic and anthropogenic *** information on total metal concentrations in sediments was not sufficient for assessing the metal behavior in the environment,but the sequential extraction technique was more effective in estimating the environmental impact of contaminated sediments.

关键词： Five-step sequential extraction Factor analyses Q-mode and R-mode cluster analysis Heavy metals Tiurmalairajan estuary

The hydraulic characteristics of end-dump closure with the assistance of backwater-sill in diversion channel

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Journal of Hydrodynamics 2016年第5期28卷 886-896页

作者：陆贺胡志根刘全吕国轩叶建群任金明 The State key Laboratory of water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China Huadong Engineering Corporation Limited of Powerchina Hangzhou 310014 China

The river closure is a key step in the water dam construction, and the end-dump closure is a general way to cut offthe river flow. The hydraulic characteristics at the closure gap are the main factors which affect the extent of closure difficulty. A method is proposed to reduce the difficulty of diversion channel closure by pre-building a closure structure called the backwater-sill at the downstream toe of the closure gap to change the flow pattern at the closure gap. The results of the physical model test and the three- dimensional numerical simulation indicate that the backwater-sill has the effects of raising the water level at the downstream toe of the closure gap, decreasing the water surface gradient, and reducing the closure drop and the flow velocity at the closure gap. The schemes with different dike widths, different closure gap widths, and different backwater-sill widths and heights are simulated. The results show that the height of the backwater-sill is the key factor affecting the hydro-indicators at the closure gap, while the influe- nce of the dike width, the closure gap width or the backwater-sill width can be ignored. The higher the backwater-sill is, the lower the hydro-indicators will be. Based on the numerical simulations and the physical model tests on the hydraulic characteristics at the closure gap of the backwater-sill assisted closure, the hydro-indicators and its calculation method are proposed to provide a theoreti- cal support for the river closure.

关键词： diversion channel closure closure structure end-dump closure backwater-sill hydraulic characteristics

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Evaluating the impacts of converting grain to vegetable fields on nitrate transport in the deep vadose zone of the North China Plain

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Journal of Geographical Sciences 2025年第1期 189-212页

作者： LIU Meiying MIN Leilei WU Lin ZHANG Yucui QI Yongqing WANG Shiqin LIU Binbin GENG Di SHEN Yanjun Hebei key Laboratory of water-Saving Agriculture Key Laboratory of Agricultural Water ResourcesCenter for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyCAS School of Advanced Agricultural Sciences University of Chinese Academy of Sciences

Nitrate （NO3-） accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO3-content in intensive agricultural *** land-use change （ALUC）,typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing *** study evaluated the changes in NO3-accumulation and transport in the deep vadose zone （DVZ,below the root zone）,and the groundwater NO3-content associated with ALUC from grain to vegetable fields in the North China Plain （NCP）.The ALUC from grain to vegetable resulted in nitrate–nitrogen （NO3--N） accumulation in DVZ increased by 235.5 kg ha-1m-1（163.2%） in the piedmont plain and 224.9 kg ha-1m-1（102.7%） in the central plain,*** change accelerated downward transport velocity in the DVZ (from 0.81±0.47 to 0.89±0.55 m yr-1in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr-1in the central plain) and increased NO3-leaching *** transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont *** impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.

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MODELING OF FREE JUMPS DOWNSTREAM SYMMETRIC AND ASYMMETRIC EXPANSIONS:THEORITICAL ANALYSIS AND METHOD OF STOCHASTIC GRADIENT BOOSTING

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Journal of Hydrodynamics 2010年第1期22卷 110-120页

作者： MOHAMED A.Nassar water and water Structures Engineering Department Faculty of EngineeringZagazig University

The general computational approach of Stochastic Gradient Boosting （SGB） is seen as one of the most powerful methods in predictive data mining. Its applications include regression analysis, classification problems with/without continuous categorical predictors. The present theoretical and experimental study aims to model the free hydraulic jump created through rectangular Channels Downstream （DS） symmetric and asymmetric expansions using SGB. A theoretical model for prediction of the depth ratio of jumps is developed using the governing flow equations. At the same time, statistical models using linear regression are also developed. Three different parameters of the hydraulic jump are investigated experimentally using modified angled-guide walls. The results from the modified SGB model indicate a significant improvement on the original models. The present study shows the possibility of applying the modified SGB method in engineering designs and other practical applications.

关键词： Stochastic Gradient Boosting (SGB) free jump symmetric asymmetric theoretical regression experiment

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A New Duplex Reverse Transcription PCR for Simultaneous Detection of Viable Cryptosporidium parvum Oocysts and Giardia duodenalis Cysts

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Biomedical and Environmental Sciences 2010年第2期23卷 146-150页

作者： SEHEE NAM GYUCHEOL LEE water Analysis and Research Center K-water Daejeon 306-711 Republic of Korea

Objective To simultaneously detect viable Cryptosporidium parvum oocysts and Giardia duodenalis cysts for the purpose of reducing time and cost spent. Methods A duplex reverse transcription polymerase chain reaction （RT-PCR） method was newly developed. Results Using duplex RT-PCR method for the hsp70 gene, viable （oo）cyst concentrations of 10^1 and l0^3 （oo）cysts/100 *** could be detected for C. parvum and G duodenalis, respectively. However, after heat-shock stimulation the expression of hsp70 mRNAs was detectable at 10^0 and 10^1 （oo）cysts/100 μL concentrations of C. parvum and G. duodenalis, respectively. Thus, the detection sensitivity was significantly increased when the viable （oo）cysts were exposed to heat shock. Conclusion This study describes a new duplex RT-PCR method for hsp70 gene to detect the viable （oo）cysts of the C. parvum and G duodenalis with less time consumed and at a lower cost. This newly developed duplex RT-PCR method may be used to detect these parasites not only in aquatic environments but also in clinical samples.

关键词： Cryptosporidiumparvum Giardia duodenalis Heat-shock RT-PCR

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