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Modelling dynamic pantograph loads with combined numerical analysis

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Railway Engineering Science 2024年第1期32卷 81-94页

作者： F.F.jackson R.Mishra j.M.Rebelo j.Santos P.Antunes j.Pombo H.Magalhaes L.Wills M.Askill School of Computing and Engineering University of HuddersfieldHuddersfieldUK School of Computing and Engineering Institute of Railway ResearchUniversity of HuddersfieldHuddersfieldUK IDMEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal ISEL Instituto Politecnico de LisboaLisbonPortugal Hitachi Rail Newton AycliffeUK Wabtec/Brecknell Willis ChardUK

Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric *** heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile,and thus aerodynamic load changes significantly with operational *** research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations,such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact ***,computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting,such as that of the recessed cavity on a Class 800 *** an aerodynamic perspective,this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing,although the difference between the two is found to reduce with increasing pantograph *** the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph *** results obtained show how considering aerodynamic forces enhance the realism of the models,leading to behaviour of the pantograph-catenary contact forces closely matching that seen in experimental tests.

关键词： Pantograph-catenary interaction Pantograph aerodynamics Computational fluid dynamics Pantograph loads Current collection performance

Editorial for the Special Issue on Emerging Technology and Advanced Application of Nondestructive Detection for Power Equipment

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Chinese journal of Electrical Engineering 2024年第1期10卷 1-2页

作者： Li j. Mei H. Li S. Tianjin University China Tsinghua Shenzhen International Graduate School China Lanzhou jiaotong University China

The rapid development of clean and renewable energy technologies represented by wind and solar energy,as well as the continuous growth of load demand,have put forward higher requirements for the safe operation of the power *** performance of power equipment based on traditional dielectric materials is often limited by various defects generated during molding,transportation,assembly,and operation,which cannot meet the reliability requirements of power systems in the new *** detection is an essential technical method in industrial development,which can detect and evaluate the defect and damage status of in-service equipment,key components,and materials without damaging the object.

关键词： service Application operation

A quantitative analysis of the US materials flow methodology and comparison to the EU methodology for MSW statistics

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Waste Disposal and Sustainable Energy 2024年第1期6卷 85-94页

作者： Demetra Tsiamis Fabio Poretti Stefano Consonni Marco j.Castaldi Earth Engineering Center Department of Chemical EngineeringThe City College of New YorkNew YorkNYUSA Dipartimento Di Energetica Politecnico Di MilanoPiazza Leonardo da Vinci 3220133MilanItaly

The European Union(EU)and the United States(US)determine municipal solid waste(MSW)statistics *** EU applies a site-specific methodology that directly measures waste whereas the US employs a materials flow methodology that estimates MSW statistics indirectly based on production and recovery data from *** study dissects the materials flow methodology and presents quantitative materials flow Sankey diagrams for the primary MSW materials to highlight data gaps that can be addressed to improve the methodology’s *** industry plastics data were applied to the materials flow methodology,and the results were within 10%of the plastics statistics reported by the US Environmental Protection Agency(US EPA).Drawbacks to the methodologies include EU measurement inaccuracies due to double-counting and not accounting for residual waste in the *** latter may partially explain why landfilling tonnages reported by the US EPA were approximately 60%less than the tonnages reported by the Waste to Energy Research and Technology Council(WTERT)in its national MSW survey that applied the EU methodology in the *** the EU,there is no US national policy that requires states to measure and report state-level waste data to the US *** improvements in US MSW statistics rely heavily on the implementation of national policies to homogenize the measurement and collection of waste data from states.

关键词： Materials flow methodology Site-specific methodology United States European Union Municipal solid waste Discrepancy

Mathematical beauty and Palladian architecture:Measuring and comparing visual complexity and diversity

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Frontiers of Architectural Research 2024年第4期13卷 729-740页

作者： ju Hyun Lee Michael j.Ostwald School of Built Environment Faculty of ArtsDesign&ArchitectureThe University of New South WalesSydneyNSW 2052Australia

Palladio’s design principles,including proportion and harmony,have often been associated with mathematical definitions of ***,the geometric and semantic properties of his fac¸ades have rarely been analysed in a holistic *** is little evidence of how mathematical beauty may be embodied in his *** research investigates complexity(fractal dimension or D)and diversity(perplexity or PP)as aesthetic indices,aiming to capture distinct characteristics of Palladian *** D and PP values of 22 Palladian villa fac¸ades are measured and analysed,before being compared with those of three Renaissance facades by Sebastiano *** combination of D and PP captures the geometric and semantic aesthetic qualities of architectural ***,the developed scatter plot of D and PP results supports the identification of four distinct aesthetic types of Palladian fac¸ade *** novel combination of D and PP measures contributes to a better understanding of one definition of the mathematical beauty of architecture,wherein“the whole is other than the sum of the parts”in compositional terms(a famous Gestalt principle).Specifically,this research provides new mathematical insights into the visual character of Palladian architecture and compares two important measures thereof.

关键词： Palladian architecture Complexity Diversity Mathematical beauty Perplexity Fac¸ade design

Stable diffusion gradients in microfluidic conduits bounded by fluid walls

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Microsystems & Nanoengineering 2024年第3期10卷 357-367页

作者： Federico Nebuloni Cyril Deroy Peter R.Cook Edmond j.Walsh Department of Engineering Science Osney Thermo-Fluids InstituteUniversity of OxfordOxford OX20ESUK Sir William Dunn School of Pathology University of OxfordOxford OX13REUK

Assays mimicking in vitro the concentration gradients triggering biological responses like those involved in fighting infections and blood clotting are essential for biomedical *** assays prove especially attractive as they allow precise control of gradient shape allied to a reduction in *** microfluidic devices are fabricated using solid plastics that prevent direct access to responding ***-walled microfluidics allows the manufacture of circuits on standard Petri dishes in seconds,coupled to simple operating methods;cell-culture medium sitting in a standard dish is confined to circuits by fluid walls made of an immiscible *** develop and experimentally validate an analytical model of diffusion between two or more aqueous streams flowing at different rates into a fluid-walled conduit with the cross-section of a circular *** solid walls,fluid walls morph during flows as pressures fall,with wall shape changing down the *** model is validated experimentally for Fourier numbersng fluorescein diffusing between laminar *** enables a priori prediction of concentration gradients throughout a conduit,so allowing rapid circuit design as well as providing bioscientists with an accurate way of predicting local concentrations of bioactive molecules around responsive and nonresponsive cells.

关键词： walls diffusion attractive

Semitransparent organic solar cells with high light utilization efficiency and color rendering index

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Science China Chemistry 2024年第7期67卷 2248-2256页

作者： Ni Gao Haijun Bin Shangrong Wu RenéA.j.janssen Yongfang Li Laboratory of Advanced Optoelectronic Materials Suzhou Key Laboratory of Novel Semiconductor Materials and DevicesCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySuzhou 215123China Molecular Materials and Nanosystems&Institute for Complex Molecular Systems Eindhoven University of TechnologyEindhoven 5600 MBthe Netherlands

Semitransparent organic solar cells(ST-OSCs)have garnered considerable attention as promising renewable energy technology for integrating photovoltaics into ***,there is a trade-off between power conversion efficiency(PCE)and average visible transmittance(AVT),which hinders the achievement of a high light utilization efficiency(LUE).In this study,we propose a valuable method to address this challenge by replacing the transparent top electrode,Ag,with a 20 nm layer of *** ST-OSCs based on the 20 nm Au electrode demonstrate superior exciton extraction,more efficient charge collection,and higher color-rendering index(CRI)due to their smoother surface,higher conductivity,and enhanced visible light transmittance,resulting in a significantly higher PCE of 13.67%and an enhanced AVT of 30.17%,contributing to a high LUE of 4.15%.Additionally,optically transparent dielectric layers,applied on the front and back sides of the ST-OSCs to further boost performance,delivered an impressive LUE of 4.93%,with PCE and AVT values reaching 14.44%and 34.12%,***,the champion ST-OSCs also exhibited a favorable CRI value of *** achievements represent the bestperforming ST-OSCs to date with both high LUE and CRI and hold significant implications for the prospective commercialization of ST-OSCs.

关键词： semitransparent organic solar cells power conversion efficiency average visible transmittance light utilization efficiency color-rendering index

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.jeong S.W.Lee W.j.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

A marathon,not a sprint:Increasing population physical activity as a legacy of sports mega-events

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journal of Sport and Health Science 2024年第6期13卷 732-735页

作者： Fiona C.Bull Paul j.Simpson Physical Activity Unit Department of Health PromotionWorld Health OrganizationGeneva CH-1211Switzerland The BMj London WC1H 9JPUK

*** matters The withdrawal of Australia as hosts for the Commonwealth Games in 2026 demonstrates that large international sporting events are more than just sporting mastery,medals,and *** also matters.1 The cost of hosting a major international tournament is eye-wateringly *** governments need to show that the billions of dollars of investment deliver a return beyond sporting glory to justify the resources that are spent.

关键词： return dollar sport

Physical activity with or without dietary intervention for the prevention of cardiovascular diseases

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journal of Sport and Health Science 2024年第6期13卷 753-755页

作者： Carl j.Lavie Salvatore Carbone Leandro Slipczuk The john Ochsner Heart and Vascular Institute Ochsner Clinical Schoolthe University of Queensland School of MedicineNew OrleansLA 70121USA Department of Kinesiology and Health Sciences College of Humanities and SciencesVirginia Commonwealth UniversityRichmondVA 23284USA Montefiore Health System/Albert Einstein College of Medicine BronxNY 10461USA

We and others have published extensively on the benefits of physical activity(PA),exercise training,and cardiorespiratory fitness(CRF)to decrease the prevalence of cardiovascular diseases(CVDs)and CVD and all-cause morbidity and mortality.^(1-5)Both PA and CRF are important;however,CRF,which is mostly obtained through PA,although there is a genetic component,seems to be even more important than PA for predicting prognosis.^(1,4-6)Certainly,the wealth of data from across the world has indicated that increasing PA to enhance CRF while mitigating sedentary behavior would go a long way to lessen the world-wide obesity epidemic and reduce CVD and all-cause mortality.

关键词： mortality prevention diseases