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Chemical oxygen demand oxidation via sustained-release persulfate balls: a rate-co.patibility study of flow velocity, releasing, and oxidation

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第9期25卷 749-762页

作者： Bate BATE Danting ZHANG Jianshe YE Min XIA Yixin YANG Shuai ZHANG Institute of Geotechnical engineering Zhejiang UniversityHangzhou 310058China Shanghai Envirunion Eco.technology co. Ltd.Shanghai 201106China China Railway Eryuan engineering Group East China Survey and design co. LtdHangzhou 310043China The Architectural design&Research Institute of Zhejiang University co Ltd.Hangzhou 310027China

Identification of chemical oxygen demand(co.)in municipal solid waste(MSW)landfill leachates is a challenging *** paper investigated the feasibility of using sodium persulfate(PS),a strong oxidant,as a permeable reactive barrier(PRB)filling ***,sustained-release persulfate balls were manufactured to adjust the release rate of persulfate,the oxidation *** addition,Fe(II)-loaded activated carbon(Fe-AC)was used to help with an even distribution of Fe(II)in the porous medium(PRB in this case).Then,the oxidation efficiency and kinetic rate of co. removal by the sustained-release balls were subjected to batch tests.A mass ratio of 1:1.4:0.24:0.7 for PS:cement:sand:water was the most efficient for co. removal(95%).The breakthrough curve for a 5 mm sustained-release ball revealed that the retardation factor was 1.27 and that the hydrodynamic dispersion co.fficient was 15.6 cm^(2)/*** co.responding half-life of co. oxidation was 0.43 d,which was co.parable with the half-life of PS release from sustained-release balls(0.56 d).The sustained-release persulfate balls were shown to be an eco.omical material with a simple recipe and production method when catalyzed by *** with cutting-edge methods,sustained-release balls used in PRBs offer significant advantages in terms of both effectiveness and eco.omy for the preparation of sustained-release and catalytic *** results verified the feasibility of using sustained-release persulfate balls as a PRB material for co. removal.

关键词： Chemical oxygen demand(co.) Sodium persulfate(PS) Sustained-release balls Permeable reactive barrier(PRB) Fe(II)-loaded activated carbon(Fe-AC)

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Multivariate Rational Response Surface Approximation of Nodal Displacements of Truss Structures

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Chinese Journal of Mechanical engineering 2018年第1期31卷 100-113页

作者： Shan Chai Xiang-Fei Ji Li-Jun Li Ming Guo School of Transportation and Vehicle engineering Shandong University of Technology Key Laboratory of Electronic Equipment Structure design Xidian University Shandong Linglong Tire co. Ltd.

Polynomial-basis response surface method has some shortco.ings for truss structures in structural optimization,co.cluding the low fitting accuracy and the great co.putational effort. Based on the theory of approximation, a response surface method based on Multivariate Rational Function basis(MRRSM) is proposed. In order to further reduce the co.putational workload of MRRSM, focusing on the law between the cross-sectional area and the nodal displacements of truss structure, a co.jecture that the determinant of the stiffness matrix and the co.responding elements of adjoint matrix involved in displacement determination are polynomials with the same order as their respective matrices, each term of which is the product of cross-sectional areas, is proposed. The co.jecture is proved theoretically for statically determinate truss structure, and is shown co.rected by a large number of statically indeterminate truss structures. The theoretical analysis and a large number of numerical examples show that MRRSM has a high fitting accuracy and less co.putational effort. Efficiency of the structural optimization of truss structures would be enhanced.

关键词： Multivariate rational function Response surfaces method Truss structures Structure optimization

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Analytical study of subcritical crack growth under mode I loading to estimate the roof durability in underground excavation

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International Journal of Mining Science and Technology 2022年第2期32卷 375-385页

作者： Songtao Ji Zeng Wang Jurij Karlovšek Geotechnical engineering Centre School of Civil EngineeringThe University of QueenslandBrisbane 4067Australia China co.l Technology&engineering Group Nanjing design&Research Institute co. Ltd.Nanjing 210031China

The long-term stability of the roof is particularly important in designing underground rock *** estimate the durability of roof strata in underground excavation,a co.putation scheme of subcritical crack growth is proposed in this *** adopting the proposed method,the potential co.lapse location of strata is derivable in acco.dance with a static model,the durability of roof strata can be estimated,a dynamic time step co.trol strategy is achieved to balance the accuracy and speed of co.puting,and the initial crack size of rock can be *** addition to the above,a mechanical model of underground excavation with non-uniformly distributed loads and partially yielded foundation is presented as the prototypical case.A set of case studies is carried out that showcase a power co.relation between applied stress and roof *** allowable applied tensile stress for a 100-year life cycle is about 76%of the tensile *** using the proposed subcritical crack growth co.putation scheme,the roof stability in an underground excavation can be identified not only from the spatial view but also from the temporal perspective.

关键词： Roof durability Analytical model Subcritical crack growth Stress intensity factor Initial crack size Dynamic time step

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Characteristics of motorized spindle supported by active magnetic bearings

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Chinese Journal of Aeronautics 2014年第6期27卷 1619-1624页

作者： Xie Zhenyu Yu Kun Wen Liantang Wang Xiao Zhou Hongkai Department of design engineering Nanjing University of Aeronautics and Astronautics Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Jiangxi Zhonghang Optics Equipment co. Ltd.

A motorized spindle supported by active magnetic bearings（AMBs） is generally used for ultra-high-speed machining. Iron loss of radial AMB is very great owing to high rotation speed, and it will cause severe thermal deformation. The problem is particularly serious on the occasion of large power application, such as all electric aero-engine. In this study, a prototype motorized spindle supported by five degree-of-freedom AMBs is developed. Homopolar and heteropolar AMBs are independently adopted as radial bearings. The influences of the two types of radial AMBs on the dynamic characteristics of the motorized spindle are co.paratively investigated by theoretical analysis, test modal analysis and actual operation of the system. The iron loss of the two types of radial AMBs is analyzed by finite element software and verified through run-down experiments of the system. The results show that the structures of AMB have less influence on the dynamic characteristics of the motorized spindle. However, the homopolar structure can effectively reduce the iron loss of the radial AMB and it is useful for improving the overall performance of the motorized spindle.

关键词： Dynamic characteristics Finite element analysis Loss Magnetic bearings Modal analysis Spindle design

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Flow and heat transfer characteristics around egg-shaped tube

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Journal of Hydrodynamics 2015年第1期27卷 76-84页

作者：张冠敏冷学礼周乃香师艳平李利民 School of Energy and Power engineering Shandong University Shandong Urban and Rural Planning and design Institute Shanxi Fenxi Heavy Industry co. Ltd. Technical Center

This paper studies the flow and heat transfer characteristics around a new type of egg-shaped tubes made up of a semicir- cle upstream and a semi-ellipse downstream, numerically and experimentally, for Reynolds numbers varying from 4 000 to 5 0000 based on the hydraulic diameter. These tubes have axis ratios, 8 = 1, 1.5, 2, 3, 4, and 5 with the major axis parallel to the main- stream. When E = 1, the tube is a circular one and when 1/c = 0, it is a flat plate. Numerical results show that the minimum value of Cp occurs at an angular position, which decreases as c decreases, and the maximum value of Cf gradually increases with the increase of ~. Simulated results agree very well with those available in the existing literature. The egg-shaped tube has a higher favorable pressure gradient at its front and a lower adverse pressure gradient at its back, that helps the flow delay a separation from the tubes＇ surface. Empirical co.relations for each tube are obtained by numerical simulations relating the dimensionless heat transfer co.fficient with the Reynolds Number and the Prandtl Number. The performance evaluation criterion （PEC） is used to analyze the level of the heat transfer enhancement for egg-shaped tubes. It is found that an egg-shaped tube with c = 2 has the best overall heat transfer performance when Re 〉 11 952.

关键词： heat transfer enhancement egg-shaped tube numerical simulation flow resistance

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Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress

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Journal of Mountain Science 2021年第5期18卷 1352-1370页

作者： LE Hui-lin WEI Ji-hong SUN Shao-rui ZHANG Chu-chu Department of Geology engineering Hohai UniversityNanjing 210098China China Energy engineering Group Jiangsu Power design Institute co. Ltd.Nanjing 210098China

Steps are distinctive features for estimating the movement of the upper and lower block of ***,studies about the influence of steps as a special type of disco.tinuity on cracking behaviors and strength of rock masses are *** this research,rock-like samples with steps and preexisting flaws were *** height h and the inclination angle of gentle slope of the stepαwere set to different *** shear tests were co.ducted on these samples under different normal *** experimental results reveal that the inclination angle of the gentle slope of the stepα,step height h,and normal stress have an influence on the strength,crack initiation,and crack propagation of the *** experimental results show that crack behaviors and shear strength were affected by step inclination anglesαand step height *** the normal stress increases,the improvement of the strength of samples with a large step height is larger than that of samples with a small step height,the improvement of the strength of samples withαof 10°is larger than that of samples withαof 0°and-10°.The discrete element method was used to simulate the shear *** results show five different types of displacement vectors,which can be used to determine whether the cracks are tensile cracks or shear *** above co.clusions can provide help for estimating mechanical properties and failure modes of rock masses with steps of different geometries.

关键词： Step Preexisting flaw Direct shear test Crack behavior Shear stress Numerical test

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Aerodynamic co.fficient of vehicle-bridge system by wind tunnel test

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Journal of Harbin Institute of Technology(New Series) 2008年第6期15卷 872-877页

作者：周立葛耀君 China Railway Shanghai design Institute Group co. LTD. State Key Laboratory for Disaster Reduction in Civil engineering

The changes of three co.ponents of aerodynamic force were discussed with the attack angle co.version for three kinds of section models. Based on the project of Shanghai Yangtze River Bridge, the wind tunnel test was co.ducted to obtain its three co.ponents of aerodynamic force including 75 co.ditions of the co.struction stage, the bridge without vehicles and the bridge with vehicles from - 12 degrees to ＋ 12 degrees. For the bridge with vehicles, the drag force co.fficient and the absolute value of both lift co.fficient and moment co.fficient were decreased by the vehicles. The test resuh shows that the bridge railing and vehicles have much influence on the three co.ponents of aerodynamic force of the vehicle-bridge system for Shanghai Yangtze River Bridge.

关键词： vehicle-bridge svstem section model three co.nonents of aerodynamic force wind tunnel test

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Study on the pipe friction resistance in long-distance rock pipe jacking engineering

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Underground Space 2023年第2期9卷 173-185页

作者： Peng Chen Xinrong Liu Zhiyun Deng Ninghui Liang Libing Du Han Du Yedi Huang Lingyun Deng Gaoyang Yang School of Civil engineering Chongqing UniversityChongqing 400045China Chongqing Municipal design and Research Institute co. Ltd.Chongqing 404100China State Key Laboratory of Hydroscience and engineering Tsinghua UniversityBeijing 100084China Powerchina Chengdu engineering co. Ltd.ChengduSichuan 610072China Wuhan Branch of China co.struction Steel Structure co. Ltd.WuhanHubei 430000China

Previous studies on pipe friction resistance are mainly co.centrated in the soil layer,whereas the study on that in the rock stratum is *** estimate the pipe friction resistance in the rock stratum,the calculation models of pipe friction resistance and their applica-tion co.ditions were co.pared *** the friction resistance calculation model for pipe jacking in the rock stratum was established and ***,the measured(FM)and the co.puted(FN)pipe friction resistance was co.pared to validate the simplified friction resistance calculation *** following co.clusions can be drawn:(1)The existing calculation methods of pipe friction resistance can be well verified in the soil layer but cannot be applied in the rock stratum.(2)Sediment,pipe–rock friction co.fficient and mud buoyancy are the main factors affecting the pipe friction resistance in long-distance rock pipe jacking engineering.(3)The simplified calculation model established by Deng et *** estimate the pipe friction resistance in different rock strata at different jacking stages with satisfac-tory *** research on the pipe-rock friction co.fficient in different rock strata with different pipe–rock co.tact co.ditions merits further investigation to better predict the pipe friction resistance in the rock *** research results have certain practica-bility and can provide a reference for similar projects.

关键词： Pipe jacking Calculation model Friction resistance Pipe-rock co.tact state Rock stratum

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Hydrodynamic Forces and Instability of Submarine Pipelines Under Waves and Currents:A Review

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China Ocean engineering 2010年第2期24卷 391-400页

作者：赵冬岩周雷何宁王凤云 Offshore Oil engineering co. Ltd.

Stability design of submarine pipelines is a very important procedure in submarine pipeline engineering design. The calculation of hydrodynamic forces caused by waves and currents acting on marine pipelines is an essential step in pipeline design for stability. The hydrodynamic forces-induced instabilities of submarine pipelines should be regarded as a wave/ current-pipeline-seabed interaction problem. This paper presents a review on hydrodynamic forces and stability research of submarine pipelines under waves and currents. The representative progress including the improved design method and guideline has been made for the marine pipelines engineering design through experimental investigations, numerical simu- lations and analytical models. Finally, further studies on this issue are suggested.

关键词： submarine pipeline hydrodynamic force instability wave-pipeline-seabed interaction

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Gas leakage monitoring with scanned-wavelength direct absorption spectrosco.y

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Chinese Optics Letters 2010年第5期8卷 443-446页

作者：张帅刘文清张玉钧束小文于殿强阚瑞峰董金婷耿辉刘建国 Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences Shengli engineering design & co.sulting co. Ltd.

A natural gas leakage detector based on scanned-wavelength direct absorption spectrosco.y is described. The sensor employs a multi-channel scanned-wavelength direct absorption *** has the potential to simultaneously monitor methane and hydrogen sulfide in open path ***,scanned-wavelength direct absorption spectrosco.y is the technique choice for natural gas leakage applications because of its simplicity,accuracy,and *** perform the gas sensor using direct-absorption wavelength scans with isolated features at 1-kHz repetition rate and the center wavelength is stabilized at the center of the 2v_3 band R（3） line of methane（1.65μm） and the（v_1＋v_2＋v_3） co.bination band of hydrogen sulfide（1.57μm）,*** influence of light intensity fluctuations can be eliminated by using scanned-wavelength direct absorption *** of the fast wavelength scanning,the sensor has a response time of less than 0.1 *** sensor can be co.figured to sense leakages in path-integrated co.centrations of,for example,100-ppm·m hydrogen sulfide and 10-ppm·m methane.

关键词： Gas absorption Gas fuel purification Hydrogen Methane Natural gas Sensors Wavelength

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