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Development of Evacuated Tube Maglev transport Test Platform and Research Progress on Aerodynamic Characteristics inside the Tube

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Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 2025年第2期61卷 181-197页

作者： Deng, Zigang Hu, Xiao Wang, Xiaofei Li, Zongpeng Zhang, Weihua State Key Laboratory of rail Transit Vehicle System Southwest Jiaotong University Chengdu610031 China Research Center for Super-High-Speed Evacuated Tube Maglev transport Southwest Jiaotong University Chengdu610031 China Gansu Province Engineering Laboratory of rail Transit Mechanics Application Engineering Lanzhou Jiaotong University Lanzhou730070 China school of Mechanics and Aerospace Engineering Southwest Jiaotong University Chengdu610031 China

As a new type of transportation system, an evacuated tube transportation system combines maglev technology with low-pressure tube technology, which theoretically minimizes the frictional and aerodynamic resistance of trains during high-speed operation. This could potentially break the speed limits of ground rail transport, achieving speeds of 1 000 km/h or more for ultra-high-speed train. To promote the development of the evacuated tube maglev transport, this overview first summarizes the current research status of evacuated tube transport test platforms both domestically and internationally, including the U.S., South Korea, and China, where the highest model test speed has reached 1 152 km/h. It then focuses on the basic scientific issues of aerodynamics within the tube, analyzing research progress in five areas: flow states within the tube, aerodynamic loads, complex wave phenomena, aerodynamic heating, and aerodynamic noise. Finally, the outlook for the development of evacuated tube transportation is discussed, highlighting key areas for future research: refined numerical simulation methods, methods to mitigate or delay choked flow, heat dissipation pathways suitable for evacuated tube transportation system, and the evolution of flow field characteristics in the tube during prolonged train operations. © 2025 Chinese Mechanical Engineering Society. All rights reserved.

关键词： Aerodynamic heating

Empirical comparison of the effects of other party's vehicle type on motorcyclists' injury severity

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Journal of Traffic and transportation Engineering(English Edition) 2025年第01期 180-200页

作者： Thanapong Champahom Chamroeun Se Wimon Laphrom Duangdao Watthanaklang Sajjakaj Jomnonkwao Vatanavongs Ratanavaraha Department of Management Faculty of Business AdministrationRajamangala University of Technology Isan school of transportation Engineering Institute of EngineeringSuranaree University of Technology Department of Construction Engineering transport and Logistics Faculty of Industrial TechnologyNakhon Ratchasima Rajabhat University

This research explores the various factors influencing the severity of injuries motorcyclists sustain across different collision scenarios. The study considers the types of vehicles involved, including motorcycle(MC), cars, pickup trucks, vans, and trucks. The study is grounded in an analysis of road crashes in Thailand from 2016 to 2019. Recognizing the unique characteristics inherent in each collision type, the study categorizes crashes into six distinct models for a comprehensive analysis. Each model is constructed using the random parameter logit with unobserved heterogeneity in means. Notably, all models incorporate random parameters, with the exception of the MC vs. truck model. Despite some consistent factors across most models, there are noteworthy variations in parameters when comparing different vehicle types. In the context of single-motorcycle crashes,speed limit violation emerges as a critical factor. For the MC vs. MC model, crashes happening from midnight to early morning are significant. The presence of a passenger(pillion) is a key determinant in the MC vs. car model. Meanwhile, in the MC vs. pickup truck model, crashes occurring under poor light conditions from midnight to early morning are of particular importance. The MC vs. van model notably highlights the involvement of male riders. Lastly, the MC vs. truck model draws attention to crashes happening on weekends. By creating specific crash models for diverse vehicle types, this study enhances our understanding of motorcycle crashes. The findings provide valuable insights to inform the development of policies, the design of safety campaigns, the creation of training programs, and the evaluation of road safety.

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Analysis on the adjustment of transportation structure and the logistics transformation of railway freight

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railway Sciences 2025年第1期4卷 82-96页

作者： Chaohe Rong Xingchan Li Gaiping Zhang Xuecheng Wang school of Economics and Management Beijing Jiaotong UniversityBeijingChina International Logistics Supply Chain Promotion Center Global Sustainable Transport Innovation and Knowledge CenterBeijingChina school of Economics and Management North China University of TechnologyBeijingChina

Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into the modern logistics *** seeks to address the need for a more nuanced understanding of the“road to rail”policy,emphasizing the importance of intermodal collaboration and service of fragmented market ***/methodology/approach–The study employs a transport economics perspective to evaluate the achievements and shortcomings of China’s transportation structure *** bases its assessment of the current state of railway freight logistics,multi-modal transportation and the broader implications for the transportation service market on data *** methodology includes a review of existing policies,an examination of industry practices and a comparative analysis with global trends in railway ***–The research underscores the importance of focusing on the development of non-bulk materials,noting the insufficiency in the development of China’s rail multi-modal transportation and highlighting the instructive value of successful cases in open-top container road-rail intermodal *** study posits that the railway sector must enhance cooperation with other market entities,aligning with the lead enterprises in the logistics chain that are characterized by speed,high value and strong coordination capabilities,in order to better serve the transportation *** approach moves away from a reliance on the railway’s own capabilities ***/value–This paper offers original insights into the transformation of railway freight in China,contributing to the body of knowledge on transportation economics and *** provides valuable recommendations for policymakers and industry practitioners,emphasizing the strategic importance of railway logistics in the context of China’s economic development and intense co

关键词： transportation structure optimization railway freight Logistics transformation Multi-modal transport

Turbulent Agglomeration of Microparticles in a Cylinder Wake Flow Using LES-DEM:Focusing on the Effect of the Reynolds Number

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Journal of Thermal Science 2025年第1期34卷 34-49页

作者： WANG Shuang MU Lin LI Xue XIE Jun DONG Ming school of Energy and Power Engineering Dalian University of TechnologyDalian 116024China school of Optical Information and Energy Engineering Wuhan Institute of TechnologyWuhan 430205China school of Energy and Environment Shenyang Aerospace UniversityShenyang 110136China

Turbulent agglomeration is viewed as a promising technology for enhancing fine particle removal *** better understand particle transport,agglomeration behaviors,and fluid-particle interactions,we numerically explored these phenomena under cylindrical vortex wake influence using a coupled large eddy simulation and discrete element method(LES-DEM)*** validity of the LES approach was verified by comparison with available direct numerical simulation(DNS)*** adopted the Johnson-Kendall-Roberts(JKR)contact model for particle-particle *** particle dispersion and agglomeration characteristics of particles with different diameters(d_(p)=2-20μm)in the laminar and transition of shear layer(TrSL)flow regimes were *** particles were concentrated at the vortex centers,while larger particles accumulated around the *** agglomeration efficiency exhibited an M-shaped profile spanwise(y-direction).With increasing Reynolds number,the agglomeration efficiency and turbulence intensity *** particle agglomeration efficiency peaks at a certain Reynolds ***,at higher Reynolds numbers,reducing the residence time of particles in the flow field decreases the agglomeration efficiency.

关键词： microparticle particle agglomeration discrete element method large eddy simulation

Modular assembly of Co4-thiacalix[4]arene units and Keggin-type SiW12O40 for visible-light photothermal conversion

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Tungsten 2025年第1期7卷 112-119页

作者： Jia-Hui Li Qing Zhao Dong-Ao Mao Kun Zhou Bao-Kuan Chen Yan-Feng Bi school of Petrochemical Engineering Liaoning Petrochemical University

The construction of metal-organic coordination clusters（MCCs） using modular secondary building units is an important method for preparing functional *** this study,two new MCCs modularly assembled from Keggin-type {SiW12O40}H4TC4A=p-tert-Butylthiacalix[4]arene(SiW12) units and thiacalixarene-supported Co4-thiacalix[4]arene(Co4-TC4A polynuclear second-building units（PSBUs,H4TC4A=p-tert-Butylthiacalix[4]arene） are *** two MCCs,abbreviated as Co4-SiW12and Co8-SiW12,were structurally characterized by single-crystal X-ray *** Co4-SiW12is a supramolecular structure involving cation-anion interactions between Co4-TC4A PSBUs and ***8-SiW12features "barbell-like" shapes with two Co4-TC4A coordinatively linked to a Keggin-type SiW12unit on opposite via W-O_t-Co *** coordination of Co4-TC4A to SiW12in Co8-SiW12resulted in significantly improved photothermal conversion performances compared with Co4-SiW12and pure SiW12or ***-gap determination and photophysical analysis combined with density functional theory calculations indicated the binding mode between Co4-TC4A PSBUs and SiW12,which considerably influences the way of electron transport and the conversion ability of visible light to heat.

关键词： Modular construction Photothermal conversion Polyoxometalate Thiacalixarene

Synchronous hybrid transport network design

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Journal of Central South University 2009年第2期16卷 332-338页

作者：李夏苗曾明华傅白白朱晓立 school of Traffic and transport Engineering Central South University State Key Laboratory of rail Traffic Control and Safety Beijing Jiaotong University

Delay,as an inevitable real-world phenomenon,is usually ignored in transport network design.A model of urban hybrid transport system with stochastic delay was created on the basis of the idealized public transport system *** formulating the total trip time cost composed of accessing time in the sub-region of the city,waiting time at the public transport station,and in-vehicle time in the public transit network,the analytical properties of the total trip time cost function were *** results show that in the urban hybrid transport network design,the total trip time cost reaches its approximate minimum in a δ-neighbourhood of buffer time of 1.5 min,and that through modelling optimal delay in hybrid transport system,the maximal synchronization can be achieved and operational efficiency and passenger satisfaction can be *** proposed modelling and analytical investigations are attempts to contribute to more realistic modelling of future idealized public transport system that involves more practical constraints.

关键词： transport network design delay synchronization total trip time cost

Molecular dynamics simulations of helium transport through inorganic mineral nanopores

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Science China Earth Sciences 2025年第1期68卷 237-252页

作者： Dandan SONG Ping GUAN Chi ZHANG Jiahao REN school of Earth and Space Sciences Peking UniversityBeijing100871China

Helium transport through nanoscale inorganic mineral pores and pore throats is essential for its overall *** elucidate helium's transport dynamics within nanopores,we employed equilibrium and non-equilibrium molecular dynamics simulations to investigate helium's static self-diffusion and pressure-driven flow in quartz slit-shaped *** also introduced water and various gases,including hydrogen,methane,ethane,nitrogen,and carbon dioxide,into the nanopores to assess their influence on helium *** findings indicate minimal helium adsorption on quartz pore *** conditions where the pore size is less than 5 nm and the pressure under 10 MPa,environmental factors markedly influence helium *** pore sizes,high temperatures,and low gas pressures enhance helium desorption and facilitate faster *** observed a positive correlation between helium flow velocity and factors such as pore size,pressure gradient,and surface smoothness of the ***,the presence of pore water and carrier gases in quartz nanopores,which diffuse more slowly than helium,tends to reduce helium surface adsorption and slow its *** the carrier gases studied,nitrogen showed similar adsorption capacity,diffusivity,and stability to helium,while carbon dioxide displayed the highest adsorption capacity and the slowest diffusion rate,markedly differing from *** on the simulation results,we concluded that water and carrier gases primarily function as transport mediums in helium migration,moving together with ***,which shares similar properties with helium,effectively assists in this co-migration ***,carbon dioxide,due to its high adsorption capacity and slow diffusion,tends to be lost during *** a result,gas reservoirs with high nitrogen levels and low carbon dioxide levels are more likely to have higher helium ***,the smaller pore sizes and higher gas pressures in caproc

关键词： Helium transport Slit nanopores Molecular dynamics simulations Diffusion Flow carriers

Synthesis of ternary geopolymers using prediction for effective solidification of mercury in tailings

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Journal of Environmental Sciences 2025年第1期147卷 392-403页

作者： Xuan Lu Jinfa Guo Fang Chen Mengkui Tian school of Chemistry and Chemical Engineering Guizhou UniversityGuiyang 550025China

This study used steel slag,fly ash,and metakaolin as raw materials(SFM materials)to create silica-alumina-based geopolymers that can solidify Hg^(2+)when activated with sodiumbased water *** experiments began with a triangular lattice point mixing design experiment,and the results were fitted,analyzed,and *** optimum SFM material mass ratio was found to be 70%steel slag,25%fly ash,and 5%*** optimum modulus of the activator was identified by comparing the unconfined compressive strength and solidifying impact on Hg^(2+)of geosynthetics with different *** SFM geopolymer was then applied in the form of potting to cure the granulated mercury *** inclusion of 50%SFM material generated a geosynthetic that reduced mercury transport to the surface soil by roughly 90%.The mercury concentration of herbaceous plant samples was also reduced by 78%.It indicates that the SFM material can effectively attenuate the migration transformation of ***,characterization methods such as XPS and FTIR were used to investigate the mechanism of Hg^(2+)solidification by geopolymers generated by SFM *** possible solidification mechanisms were proposed as alkaline environment-induced mercury precipitation,chemical bonding s,surface adsorption of Hg^(2+)and its precipitates by the geopolymer,and physical encapsulation.

关键词： Mercury Geopolymer Solidification Tailings

Effect of sea surface temperature during critical early life history stages of Portunus trituberculatus on later yield

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Journal of Oceanology and Limnology 2025年第1期43卷 313-325页

作者： Kaiming XIA Baogui LIU Jiale QIAO Yingbin WANG school of Fishery Zhejiang Ocean UniversityZhoushan 316022China

The early life stages of marine organisms are pivotal in shaping community dynamics and resource *** this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy,and examined the effect of sea surface temperature(SST)in its critical early life stages on subsequent *** analyze the correlation between SST in different larval stages and the corresponding yield of ***,we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments(LPTE).In the five years(2014,2015,2016,2019,and 2020),particles were transported in a northwestern direction and moved in the direction of low *** distribution of particles in the megalopa stage(M stage)were located in the region of the lower *** 2017,2018,and 2021,the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years,and the particles in the last M stage were located in the region where the SST was at the peak of the time *** 2022,the distribution was observed for most of the particles in the southwestern part of Zhejiang coast,a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang *** correlations between the SST at each stage of larvae with the corresponding year's yield showed that the yield of *** decreased significantly(R=-0.772,P=0.015)with increasing SST at the M *** study preliminarily explains the correlation between SST at the larval stage and the yield of *** and provides essential information for scientific stock enhancement in the future.

关键词： East China Sea swimming crab(Portunus trituberculatus) larval stage development Lagrangian particle tracking spatial-temporal dynamics sea surface temperature