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A co.laborative strategy for enhanced reduction of Cr(Ⅵ) by Fe(0) in the presence of oxalate under sunlight:Performance and mechanism

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Journal of Environmental Sciences 2020年第4期32卷 385-394页

作者： Qi Zhou Yang Li Heng Yang Yun Gao co.lege of Chemistry and Chemical Engineering Anhui UniversityHefei 230601China Guangzhou Key Laboratory of Environmental Catalysis and Pollution co.trol School of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China chengdu Integrated Testing Center of Rocks and Ores Sichuan Geology and Mineral Exploration and Development BureauChengdu 610081China Anhui Electric Power construction Seco.d Engineering co.Ltd. China Energy Construction GroupHefei 230000China

Nanometer-size zero-valent iron(NZVI)is an efficient reducing agent,but its surface is easily passivated with an oxide layer,leading to reaction *** our study,oxalate(OA)was introduced into this heterogeneous system of NZVI,which co.ld form ferrioxalate co.plexes with the NZVI surface-bound Fe3+and dissolved Fe3+in the *** of ferrioxalate co.plexes can facilitate the generation of Fe2+from Fe3+and co.·-radical,both species have strong reduction ***,a"photo-oxalate-Fe(0)"system through sunlight induction was established,which not only prohibited the formation of a surface passivation layer,but also displayed a synergetic mechanism of ferrioxalate photolysis to enhance reduction,exhibiting remarkably higher degradation activity(several times faster)toward the model pollutant Cr(Ⅵ)than the mechanism with NZVI *** tests suggested that both NZVI dosage and OA co.tent markedly affected the reduction *** pH was beneficial to the reduction ***,recyclability experiment showed that the reduction rate decreased from 0.21706 to 0.03977 min-1 after three cycles of reuse due to the NZVI losing reaction activity generally,but the system still maintained co.siderable reduction ***,a mechanism was revealed whereby NZVI would transform to Fe oxides after the exhaustion of its reductive power,and the photolysis of ferrioxalate to promote the cycling of iron species played the predominant role in providing extra reduction *** features co.firm that introduction of OA into Cr(Ⅵ)reduction by NZVI through sunlight induction is advantageous and promising.

关键词： Nanometer-size zero-valent iron Oxalate Sun irradiation Photolysis of ferrioxalate Cycling of surface iron Synergetic mechanism

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Research and application of thermal insulation effect of natural gas hydrate freezing co.er based on the wireline-co.ing principle

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Petroleum Science 2022年第3期19卷 1291-1304页

作者： Yun-Qi Hu Jing Xie Shou-Ning Xue Meng Xu Cheng-Hang Fu Hui-Lan He Zhi-Qiang Liu Shao-Ming Ma Si-Qing Sun Chuan-Liu Wang School of Mechanical Engineering Sichuan UniversityChengdu610065China MOE Key Laboratory of Deep Underground Science and Engineering Sichuan UniversityCollege of Water Resource and HydropowerSichuan UniversityChengdu610065China Zhensha Hydropower construction Management Branch of Guoneng Dadu River Basin Hydropower development co.Ltd Leshan614700SichuanChina Jin Shi Drill Tech co. LtdTangshan063004HebeiChina Xi'an Research Institute China Coal Technology&Engineering Group CorpXi'an710077ShaanxiChina

Natural gas hydrate(NGH)holds great promise as a source of clean *** is critical for acquiring the largest possible in situ NGH co.e for NGH eigen features and resource ***,the existing NGH co.ing technology has limitations,such as temperature increments,limited co.ing diameters,low co.ing rates,and co.plex co.ing ***,this study designs and proposes an NGH freezing co.ing(NGHFC)method and verifies the freezing and co.ing capacities of the NGHFC method in laboratories and experimental *** suggest that NGHFC shows good freezing and heat-retention properties.A freezing co.e heat transfer model is *** to the actual air temperature and operating time,the optimum initial temperature of the co.d source can be determined using this *** average co.ing rate of NGHFC can reach 77.86%.The research results will provide a new idea of co.ing gas hydrates.

关键词： Natural gas hydrate co.ing co.d source freezing In situ temperature and pressure

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An overview of Hadoop applications in transportation big data

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第5期10卷 900-917页

作者： Changxi Ma Mingxi Zhao Yongpeng Zhao School of Traffic and Transportation Lanzhou Jiaotong UniversityLanzhou 730070China Key Laboratory of Railway lndustry on Plateau Railway Transportation Intelligent Management and co.trol Lanzhou Jiaotong UniversityLanzhou 730070China Gansu highway Traffic construction Group co. Ltd.Lanzhou 730000China

As an open-source cloud co.puting platform,Hadoop is extensively employed in a variety of sectors because of its high dependability,high scalability,and co.siderable benefits in processing and analyzing massive amounts of ***,to derive valuable insights from transportation big data,it is essential to leverage the Hadoop big data platform for analysis and *** summarize the latest research progress on the application of Hadoop to transportation big data,we co.ducted a co.prehensive review of 98 relevant articles published from 2012 to the ***,a bibliometric analysis was performed using VOSviewer software to identify the evolution trend of ***,we introduced the co.e co.ponents of ***,we systematically reviewed the98 articles,identified the latest research progress,and classified the main application scenarios of Hadoop and its optimization *** on our analysis,we identified the research gaps and future work in this *** review of the available research highlights that Hadoop has played a significant role in transportation big data research over the past ***,the focus has been on transportation infrastructure monitoring,taxi operation management,travel feature analysis,traffic flow prediction,transportation big data analysis platform,traffic event monitoring and status discrimination,license plate reco.nition,and the shortest ***,the optimization framework of Hadoop has been studied in two main areas:the optimization of the co.putational model of Hadoop and the optimization of Hadoop co.bined with *** research results have been achieved in the field of transportation big ***,there is less systematic research on the co.e technology of Hadoop,and the breadth and depth of the integration development of Hadoop and transportation big data are not *** the future,it is suggested that Hadoop may be co.bined with other big data frameworks such a

关键词： Information technology Transportation big data Hadoop Intelligent transportation Cloud co.puting

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Fuzzy-support vector machine geotechnical risk analysis method based on Bayesian network

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Journal of Mountain Science 2019年第8期16卷 1975-1985页

作者： LIU Yang ZHANG Jian-jing ZHU Chong-hao XIANG Bo WANG Dong School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Sichuan Provincial Transport Department highway Planning SurveyDesign and Research instituteChengdu 610041China

Machine learning method has been widely used in various geotechnical engineering risk analysis in recent years. However, the overfitting problem often occurs due to the small number of samples obtained in history. This paper proposes the FuzzySVM(support vector machine) geotechnical engineering risk analysis method based on the Bayesian network. The proposed method utilizes the fuzzy set theory to build a Bayesian network to reflect prior knowledge, and utilizes the SVM to build a Bayesian network to reflect historical samples. Then a Bayesian network for evaluation is built in Bayesian estimation method by co.bining prior knowledge with historical samples. Taking seismic damage evaluation of slopes as an example, the steps of the method are stated in detail. The proposed method is used to evaluate the seismic damage of 96 slopes along roads in the area affected by the Wenchuan earthquake. The evaluation results show that the method can solve the overfitting problem, which often occurs if the machine learning methods are used to evaluate risk of geotechnical engineering, and the performance of the method is much better than that of the previous machine learning methods. Moreover,the proposed method can also effectively evaluate various geotechnical engineering risks in the absence of some influencing factors.

关键词： Geotechnical evaluation Overfitting problem Bayesian network Prior knowledge Fuzzy set theory Support vector machine

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Deformation mechanism and co.lapse treatment of the rock surrounding a shallow tunnel based on on-site monitoring

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Journal of Mountain Science 2020年第12期17卷 2897-2914页

作者： QIU Hong-zhi CHEN Xiao-qing WU Qi-hong WANG Ren-chao ZHAO Wan-yu QIAN Ke-jiang School of Architecture and Civil Engineering Chengdu UniversityChengdu 610106China Key Laboratory of Mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Hunan International Scientific and Technological Innovation co.peration Base of Advanced construction and Maintenance Technology of highway Changsha University of Science&TechnologyChangsha 410114China School of co.puter Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

When tunnels are co.structed at shallow depths in areas with poor geological co.ditions,such as portal sections,valleys and hillsides in regions with granitic bedrock,co.siderable excavation-induced deformation of the surrounding rock may occur,potentially resulting in tunnel *** main reason for these problems is the lack of understanding of the deformation mechanism and evolution of the soft granitic rock surrounding the tunnel and the adoption of inappropriate construction technology and *** article analyzes the deformation mechanism of the rock surrounding a shallow tunnel based on in situ monitoring data as a case study and suggests that certain measures should be taken to effectively co.trol the deformation of the surrounding rock and to minimize the potential for tunnel *** results show that the deformation of the granitic soil surrounding the tunnel can be divided into three stages:the rapid deformation stage,the slow deformation stage and the stabilization *** construction methods should be carefully selected to ensure safety during tunnel excavation in the first *** avoid seco.dary disasters caused by tunnel co.lapses,three treatment measures may be implemented as part of safety management:enhancing the monitoring of the surrounding rock deformation,adjusting the construction methods and optimizing the support *** particular,accurate monitoring data and timely information feedback play a vital role in tunnel ***,engineers with co.siderable engineering experience and professional knowledge are needed to analyze the monitoring data and make accurate predictions of tunnel deformation to ensure that reasonable measures are taken in the process of shallow tunnel excavation.

关键词： Shallow tunnel Surrounding rock deformation Field monitoring Treatment for co.lapse Information feedback

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Dynamic Design and construction of highway Cut Slopes in Huangshan Area, China

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Journal of Mountain Science 2011年第2期8卷 154-165页

作者： JU Nengpan ZHAO Jianjun HUANG Runqiu DUAN Haipeng State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China Anhui Provincial co.munication-Investment Group co. Ltd. Hefe 230088China

Deformation and failure of high slope impact the construction and operation safety of highway in the mountainous areas. The deformation and failure are mainly caused by poor design which normally has not well co.bined with the geological co.ditions and unplanned construction. Therefore, effective design and construction management should be co.ducted for ensuring a successful construction without damage and risk. In light of the reality of high slope construction along highway in the Huangshan area, this paper proposes a technical procedure for dynamic design and construction management of high slopes along highway in the mountainous area. The proposed construction management scheme is divided into three phases, i.e., 1) design phase, 2) preparation phase of excavation, and 3) construction phase. During the design phase, experiences and lessons learnt from the design and construction of other high slopes along highway in the same region are summarized. The number of slopes and slope height should be optimized from the aspects of route selection and route form. During the preparation phase of excavation, "Excavation Permit Management System" should be adopted, and construction scheme should be made by the construction unit, then the scientific research and design unit determine whether it guarantees slope stability and makes optimization measures. During the construction phase, the scientific research unit would make proposal of optimization design, and apply the achievements of scientific research into practice through co.mon efforts of various units based on the understanding of excavation and investigation. The management system mentioned above is adopted to co.duct dynamic design and construction management for more than 90 slopes along the Huangshan - Taling - Taolin Expressway, and successful results of application have been achieved.

关键词： highway cut slopes Dynamic design and construction Excavation Permit Management System Slope stability

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Different Curing Systems on Mechanical Properties of Ultra-High Performance co.crete with co.rse Aggregate

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Journal of Donghua University(English Edition) 2017年第4期34卷 492-497页

作者：赵秋杨明庄一舟聂宇 co.lege of Civil Engineering Fuzhou University CCCC Seco.d highway co.sultants co. Ltd.

High durability and high tensile strength makes ultra-high performance co.crete( UHPC) an ideal material for bridges,while its early shrinkage in the construction of cast-in-situ mass co.crete leads structure crack-easily,which restricts the application of UHPC in deck system. Whether reasonable amount of co.rse aggregate can influence the strength of UHPC and improve the shrinkage performance or reduce the co.t is still in doubt. Besides,in order to improve its co.structability and workability, whether autoclaved curing system of UHPC can be changed remains to be further researched. In response to these circumstances, a systematic experimental study on the strength of UHPC mixed with co.rse aggregate in different ratios has been presented in this paper. The three curing systems,namely standard curing,180-200 ℃/1. 1 MPa autoclaved curing,and hot water curing were tested to reveal the relationship between UHPC's properties and curing systems,and the UHPC ' s microstructure was also preliminarily studied by scanning electron microsco.e( SEM). The experimental research can draw the following co.clusions. Under the co.dition of the same mix ratio, autoclaved curing guarantees the highest co.pressive strength,followed by hot water curing and standard curing. The co.pressive strength of co.crete increases with the temperature in the range of 25 to 90 ℃ hot water curing,and high temperature in precuring period can speed up the strength development of UHPC,but the sequence of precuring period does not obviously affect the results. In 90 ℃ hot water and autoclaved curing,the strength is over 150 MPa,and it has little relation with gravel ratio. While the value increases first and then decreases in a lower temperature curing with the increasing of gravel amount,even only about 80 MPa at room temperature. The strength increases moderately along with the increase of the curing age by standard curing,especially in the initial stage.

关键词： ultra-high performance co.crete(UHPC) co.rse aggregate curing system strength microstructure

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Application study on the first cable-stayed bridge with CFRP cables in China

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Journal of Traffic and Transportation Engineering(English Edition) 2015年第4期2卷 242-248页

作者： Kuihua Mei Yajuan Li Zhitao Lu School of highway Chang'an University CCCC First highway co.sultants co. Ltd. School of Civil Engineering Southeast University Chinese Academy of Engineering

In order to push forvcard the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main co.ponents of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During co.structing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge co.ld meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values acco.d well with the calculated values. Further, creep deforma- tion of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

关键词： Cable-stayed bridgeFinite element methodCFRP cableBond-type anchorage

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Advances in thermokarst lake research in permafrost regions

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Research in co.d and Arid Regions 2014年第4期6卷 388-397页

作者： FuJun Niu GuoDong Cheng Jing Luo ZhanJu Lin State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Key Laboratory of highway construction & Maintenance Technology in Permafrost Region Ministry of TransportFirst Highway Consultants Co. Ltd. of China Communications Construction Company University of Chinese Academy of Sciences

A thermokarst lake is defined as a lake occupying a closed depression formed by ground settlement following thawing of ice-rich permafrost or the melting of massive ice. As it is the most visible morphologic landscape developed during the process of permafrost degradation, we reviewed recent literature on thermokarst studies, and summarized the main study topics as： development and temporal evolution, carbon release, and eco.ogical and engineering influence of thermokarst lakes. The climate warming, forest fires, surface water pooling, geotectonic fault and anthropogenic activity are the main influencing factors that cause an increase of ground temperatures and melting of ice-rich permafrost, resulting in thermokarst lake formation. Normally a thermokarst lake develops in 3–5 stages from initiation to permafrost reco.ery. Geo-rectified aerial photographs and remote sensing images show that thermokarst lakes have been mainly experiencing the process of shrinkage or disappearance in most regions of the Arctic, while both lake numbers and areas on the Qinghai-Tibet Plateau have increased. Field studies and modeling indicates that carbon release from thermokarst lakes can feedback significantly to global warming, thus enhancing our understanding of the influences of thermokarst lakes on the eco.ogical environment, and on regional groundwater through drainage. Based on field monitoring and numerical simulations, infrastructure stability can be affected by thermal erosion of nearby thermokarst lakes. This review was undertaken to enhance our understanding of thermokarst lakes, and providing references for future co.prehensive studies on thermokarst lakes.

关键词： thermokarst lake permafrost ground ice environment engineering influence

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Effects of co.l mining and tunnel excavation on groundwater flow system in karst areas by modeling:A case study in Zhongliang Mountain,Chongqing,Southwest China

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Journal of Groundwater Science and Engineering 2023年第4期11卷 391-407页

作者： Qing-shan Li Xiao-bing Kang Mo Xu Bang-yan Mao Sichuan Tianshengyuan Environmental Service co. LtdChengdu 610036China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China China Railway Eryuan Engineering Group co. Ltd.Chengdu 610031China

A karst groundwater system ranks among the most sensitive and vulnerable types of groundwater *** mining and tunnel excavation can greatly change the natural hydrogeological flow system,groundwater-dependent vegetation,soil,as well as hydrology of surface water *** co.l mine caves and proposed highway tunnels may have significant influences on groundwater *** study employs MODFLOW,a 3D finite-difference groundwater model software,to simulate the groundwater system's response to co.l mining and tunnel excavation impact in Zhongliang Mountain,Chongqing,from 1948 to *** results show a regional decline in groundwater levels within the study area following mining and tunnel *** groundwater flow system in the study area evolves from the Jialing River groundwater flow system to enco.pass the Jialing River,Moxinpo highway tunnel,Moxinpo,and the Liujiagou co.l mine cave groundwater flow systems between 1948 and *** the co.pletion of tunnel construction,the groundwater level at the top of the tunnel is gradually restored to the water level in the natural *** model also predicts groundwater level variations between 2025 and *** groundwater level will rise further initially,however,it may take about 10 years for the system to stabilize and reach a new *** light of these findings,it is advised that changes in groundwater flow systems caused by tunnel construction should be modeled prior to the practical *** approach is crucial for evaluating potential engineering and environmental implications.

关键词： Human activities Aquifer system Evolution of groundwater system Numerical modeling

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