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Drinking water quality & health risk assessment of secondary water supply systems in residential neighborhoods

Frontiers of Environmental Science & Engineering 2024年第2期18卷 47-62页

作者： Yating Wei Dong Hu Chengsong ye heng Zhang Haoran Li Xin Yu College of the Environment&Ecology Xiamen UniversityXiamen 361102China School of Public Health Shandong First Medical University&Shandong Academy of Medical SciencesJinan 250117China

Secondary water supply systems(SWSSs)are important components of the water supply infrastructure that ensure residents’drinking water *** are characterized by long detention time,warm temperature,and unreasonable management,which may trigger the deterioration of water quality and increase *** this study,drinking water quality index(DWQI)and health risk assessment(HRA)were selected and modified to quantitatively assess the water quality and health risks of SWSSs in residential *** total,121 seasonal water samples were *** was observed that the water quality was excellent with the DWQI of 0.14±0.04,excluding one sample,which was extremely poor owing to its excessive total bacterial *** HRA results revealed that the health risks were low:negligible non-carcinogenic risk for any population;negligible and acceptable carcinogenic risk for children aged 6–17 and ***,samples revealed higher carcinogenic risk(7.63×10−5±3.29×10−6)for children aged 0–5,and arsenic was the major *** samples had poor water quality and higher health risks,which called for *** further investigate the water quality and health risks of SWSSs,monthly sampling was conducted during *** 24 water samples were qualified in Chinese standard(GB 5749-2022)and characterized as excellent *** HRA results were consistent with the seasonal samples’and the health risks were mainly concentrated in ***,our study provides a suitable framework for water quality security,advice for managers,and references for administrators in other cities.

关键词： Drinking water quality Water quality index Health risk assessment Secondary water supply systems Heavy metals

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Influence of vibration on the lubrication effect of a splash-lubricated gearbox

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 324-339页

作者： Yi LIU Kailin ZHANG Shuai SHAO Hongxu xiang Zhijian ye State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

In this study,we investigate the effect of rail vibrations on the lubrication and efficiency of a splash-lubricated gearbox;specifically,the gearbox of a rail-transit vehicle.A high-fidelity 3D numerical model of the gearbox in a moving reference system is described,as well as computational fluid dynamics(CFD)simulations of the gearbox with different vibration *** effects of rotational speed,oil-immersion depth,and different oil-injection volume rates on lubrication and efficiency are *** propose a method of evaluating the internal lubrication condition of a splash-lubricated gearbox and quantitatively compare the effects of different operating parameters on lubrication and ***,our experiment to verify the feasibility of the simulation method is *** results show that with vibration,the churning loss and oil supply for the bearings are significantly higher than those under static *** addition,among different vibrational directions,lateral vibration has the greatest influence on the lubrication condition and efficiency of the *** the studied railway-vehicle gearbox,the best lubrication condition is achieved at a rotational speed of 1600 r/min and an oil-immersion depth of two times the tooth height(***).Rotational speed is the operating parameter that has the most significant effect on the lubrication and efficiencyofthegearbox.

关键词： Comprehensive lubrication evaluation Churning loss Moving reference system Splash lubrication Vibrational excitation Gearbox

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Meta-Auto-Decoder:a Meta-Learning-Based Reduced Order Model for Solving Parametric Partial Differential Equations

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1096-1130页

作者： Zhanhong ye xiang Huang Hongsheng Liu Bin Dong Beijing International Center for Mathematical Research Peking UniversityBeijing 100871China School of Computer Science and Technology University of Science and Technology of ChinaHefei 230027AnhuiChina Central Software Institute Huawei Technologies Co.LtdHangzhou 310007ZhejiangChina Center for Machine Learning Research Peking UniversityBeijing 100871China

Many important problems in science and engineering require solving the so-called parametric partial differential equations(PDEs),i.e.,PDEs with different physical parameters,boundary conditions,shapes of computational domains,*** reduced order modeling techniques accelerate the solution of the parametric PDEs by projecting them onto a linear trial manifold constructed in the ofline *** methods often need a predefined mesh as well as a series of precomputed solution snapshots,and may struggle to balance between the efficiency and accuracy due to the limitation of the linear *** the nonlinear representation of neural networks(NNs),we propose the Meta-Auto-Decoder(MAD)to construct a nonlinear trial manifold,whose best possible performance is measured theoretically by the decoder *** on the meta-learning concept,the trial manifold can be learned in a mesh-free and unsupervised way during the pre-training *** adaptation to new(possibly heterogeneous)PDE parameters is enabled by searching on this trial manifold,and optionally fine-tuning the trial manifold at the same *** numerical experiments show that the MAD method exhibits a faster convergence speed without losing the accuracy than other deep learning-based methods.

关键词： Parametric partial differential equations(PDEs) Meta-learning Reduced order modeling Neural networks(NNs) Auto-decoder

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Preparation and Reinforcement Adaptability of Jute Fiber Reinforced Magnesium Phosphate Cement Based Composite Materials

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 999-1009页

作者：刘芯州郭远臣 WANG Rui xiang Kai WANG Xue ye Qing College of Civil Engineering Chongqing Three Gorges UniversityChongqing 404100China

To improve the brittleness characteristics of magnesium phosphate cement-based materials(MPC)and to promote its promotion and application in the field of structural reinforcement and repair,this study aimed to increase the toughness of MPC by adding jute fiber,explore the effects of different amounts of jute fiber on the working and mechanical properties of MPC,and prepare jute fiber reinforced magnesium phosphate cement-based materials(JFRMPC)to reinforce damaged *** improvement effect of beam performance before and after reinforcement was compared,and the strengthening and toughening mechanisms of jute fiber on MPC were explored through microscopic *** experimental results show that,as the content of jute fiber(JF)increases,the fluidity and setting time of MPC decrease continuously;When the content of jute fiber is 0.8%,the compressive strength,flexural strength,and bonding strength of MPC at 28 days reach their maximum values,which are increased by 18.0%,20.5%,and 22.6%compared to those of M0,*** beam strengthened with JFRMPC can withstand greater deformation,with a deflection of 2.3 times that of the unreinforced beam at *** strain of the steel bar is greatly reduced,and the initial crack and failure loads of the reinforced beam are increased by 192.1%and 16.1%,respectively,compared to those of the unreinforced *** JF added to the MPC matrix dissipates energy through tensile fracture and debonding pull-out,slowing down stress concentration and inhibiting the free development of cracks in the matrix,enabling JFRMPC to exhibit higher strength and better *** JF does not cause the hydration of MPC to generate new compounds but reduces the amount of hydration products generated.

关键词： magnesium phosphate cement jute fiber reinforcement of damaged beam flexural behavior

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Double-ring high-frequency common-mode switching oscillation current sensor for inverter-fed machine winding insulation monitoring

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Global Energy Interconnection 2024年第1期7卷 106-116页

作者： Lingqing Pan Xizhou Du Xing Lei Ting ye Dawei xiang Hao Li College of Electrical Power Engineering Shanghai University of Electric PowerShanghai 200090P.R.China State Grid Shanghai Municipal Electric Power Company Shanghai 200122P.R.China College of Electronics and Information Engineering Tongji UniversityShanghai 201804P.R.China

Insulation failure significantly contributes to the unpredictable shutdown of power *** to the partial discharge and high-frequency(HF)injection methods,the HF common-mode(CM)leakage current method offers a non-intrusive and highly sensitive ***,the detection of HF CM currents is susceptible to interference from differential-mode(DM)currents,which exhibit high-amplitude and multifrequency components during normal *** address this challenge,this paper proposes a double-ring current sensor based on the principle of magnetic shielding for inverter-fed machine winding insulation *** inner ring harnesses the magnetic aggregation effect to isolate the DM current magnetic field,whereas the outer ring serves as the magnetic core of the Rogowski current sensor,enabling HF CM current ***,the magnetic field distributions of the CM and DM currents were ***,a correlation between the sensor parameters and signal-to-noise ratio of the target HF CM current was ***,an experimental study was conducted on a 3-kW PMSM for *** results indicate that the proposed double-ring HF CM sensor can effectively mitigate DM current *** to a single-ring sensor,a reduction of approximately 40%in the DM component was achieved,which significantly enhanced the precision of online insulation monitoring.

关键词： Magnetic shielding Double-ring Common-mode current Maxwell simulation

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Investigation on cavitating turbulent flow for the twisted NACA66 hydrofoil using a PANS model with helicity modification

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Journal of Hydrodynamics 2024年第2期36卷 219-231页

作者： Chen Geng Zhao-hui Qian Ke-xin Zheng Wei-xiang ye Xian-wu Luo State Key Laboratory of Hydroscience cand Engineering Deparment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

In the present paper,the unsteady cavitating turbulent flow over the twisted NACA66 hydrofoil is investigated based on an modified shear stress transfer k-ωpartially averaged Navier-Stokes(MSST PANS)model,i.e.,new MSST PANS(NMSST PANS)model,where the production term of kinetic energy in the turbulence model is modified with *** with the experimental data,cavitation evolution and its characteristic frequency are satisfactorily predicted by the proposed NMSST PANS *** is revealed that the interaction among the main flow,the reentrant jets,and sheet cavitation causes the formation of the primary shedding cavity near the mid-span and the secondary shedding cavity at each side of the twisted hydrofoil,and further induces the remarkable pressure gradient around shedding *** with the development of the primary and the secondary shedding cavities,the great pressure gradient associated with large cavity volume variation promotes the vortical flow generation and the spatial deformation of vortex structure during cavitation evolution,and results in the primary and the secondary U-type ***,dynamic mode decomposition(DMD)analysis is utilized to confirm the interaction among the main flow,the main reentrant jet and two side reentrant jets,and *** results indicate that the proposed NMSST PANS model is suitable to simulate the complicated cavitating turbulent flow for various engineering applications.

关键词： Cavitating turbulent flow partially averaged Navier-Stokes(PANS)model hydrofoil numerical simulation

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Preparation and Rheological Characterization of Long Chain Branching Polyglycolide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-Lin Liu Ming-Fu Lyu heng-Yuan Zhang Jian-ye Liu Shi-Jun Zhang Beijing University of Chemical Technology Beijing 100029China SINOPEC(Beijing)Research Institute of Chemical Industry Co. Ltd.Beijing 100013China

The long chain branching(LCB)polyglycolide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of LCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher viscosity and the more notable strain hardening behavior of modified PGA indicates the LCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical CO_(2)foaming can be carried out successfully.

关键词： Polyglycolide(PGA) Long chain branching(LCB) Rheology

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An in-situ study of static recrystallization in Mg using high temperature EBSD

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Journal of Magnesium and Alloys 2024年第4期12卷 1419-1430页

作者： Xu ye Zhe Suo Zhonghao heng Biao Chen Qiuming Wei Junko Umeda Katsuyoshi Kondoh Jianghua Shen School of Aeronautics Northwestern Polytechnical UniversityXi’anShaanxiChina Shaanxi Key Laboratory of Impact Dynamic and Its Engineering Application Xi’anShaanxiChina School of Mechanical Engineering Qinghai UniversityXiningQinghaiChina School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’anShaanxiChina Department of Mechanical Engineering University of North Carolina at CharlotteCharlotteNCUSA Joining and Welding Research Institute Osaka University11-1 MihogaokaOsakaJapan

It has been a common method to improve the mechanical properties of metals by manipulating their microstructures via static recrystallization,i.e.,through heat ***,the knowledge of recrystallization and grain growth is critical to the success of the *** the present work,by using in-situ high temperature EBSD,the mechanisms that control recrystallization and grain growth of an extruded pure Mg were *** experimental results revealed that the grains of priority for dynamic recrystallization exhibit fading competitiveness under static *** is also found that grain boundary movement or grain growth is likely to show an inverse energy gradient effect,i.e.,low energy grains tend to swallow or grow into high energy grains,and grain boundaries of close to 30°exhibit superior growth advantage to *** finding is that{10-12}tensile twin boundaries are sites of hardly observed for recrystallization,and are finally swallowed by adjacent recrystallized *** above findings may give comprehensive insights of static recrystallization and grain growth of Mg,and may guide the design of advanced materials processing in microstructural engineering.

关键词： Pure Mg In-situ HT-EBSD Recrystallization Grain growth

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Atroposelective Synthesis of 2-Arylindoles via Chiral Phosphoric Acid-Catalyzed Direct Amination of Indoles

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Chinese Journal of Chemistry 2024年第7期42卷 731-735页

作者： Wen Bao ye-Hui Chen Yu-Wei Liu Shao-Hua xiang Bin Tan School of Pharmacy&StateKey Laboratory of Applied Organic Chemistry Lanzhou UniversityLanzhouGansu 730000China Shenzhen Grubbs Institute Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong 518055China

Indole-based atropisomers are a very important class of axially chiral ***,the atroposelective synthesis of axially chiral 2-arylindole remains largely *** this study,we report the successful synthesis of atropisomeric 2-arylindoles using direct amination of indoles with p-quinonediimines in the presence of chiral phosphoric acid as a *** acts as an aminating reagent through formal polarity inversion of *** malonate group on the 2-aryl of 2-indoles was found to be essen-tial for high enantioselectivity of the *** could be due to the additional interaction between the ester group and the cata-lyst,as well as the intramolecular hydrogen *** findings provide a new strategy for the asymmetric construction of 2-arylindole atropisomers.

关键词： Chiral phosphoric acid Quinonediimines Direct amination Nucleophilic addition Asymmetric catalysis Enantioselectivity Axially chiral 2-arylindole Atroposelective synthesis

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Large-scale model testing of high-pressure grouting reinforcement for bedding slope with rapid-setting polyurethane

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Journal of Mountain Science 2024年第9期21卷 3083-3093页

作者： ZHANG Zhichao TANG Xuefeng LIU Kan ye Longzhen HE xiang Key Laboratory of Geohazard Prevention of Hilly Mountains Ministry of Natural Resources of ChinaFujian Geological Engineering Survey InstituteFuzhou 350002China Technology Innovation Center for Monitoring and Restoration Engineering of Ecological Fragile Zone in Southeast China Ministry of Natural ResourcesFuzhou 350001China School of Civil and Environmental Engineering Nanyang Technological UniversitySingapore 639798Singapore

Bedding slope is a typical heterogeneous slope consisting of different soil/rock layers and is likely to slide along the weakest *** slope protection methods for bedding slopes,such as retaining walls,stabilizing piles,and anchors,are time-consuming and labor-and *** study proposes an innovative polymer grout method to improve the bearing capacity and reduce the displacement of bedding slopes.A series of large-scale model tests were carried out to verify the effectiveness of polymer grout in protecting bedding ***,load-displacement relationships and failure patterns were analyzed for different testing slopes with various dosages of *** show the great potential of polymer grout in improving bearing capacity,reducing settlement,and protecting slopes from being crushed under *** polymer-treated slopes remained structurally intact,while the untreated slope exhibited considerable damage when subjected to loads surpassing the bearing *** is also found that polymer-cemented soils concentrate around the injection pipe,forming a fan-shaped sheet-like *** study proves the improvement of polymer grouting for bedding slope treatment and will contribute to the development of a fast method to protect bedding slopes from landslides.

关键词： Polyurethane Bedding slope Grouting Slope protection Large-scale model test

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