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Consideration of the influence of supports in modeling the electromagnetic fields of 25 kV traction networks under emergency conditions

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Global Energy Interconnection 2024年第4期7卷 528-540页

作者： Konstantin Suslov Andrey Kryukov Ekaterina Voronina Pavel Ilyushin department of Hydropower and Renewable Energy National Research UniversityMoscow Power Engineering InstituteMoscow 11250Russia department of Power Supply and Electrical engineering Irkutsk National Research Technical UniversityIrkutsk 664074Russia department of transport Electric Power Irkutsk State Transport UniversityIrkutsk 664074Russia department of Research on the Relationship between Energy and the Economy Energy Research Institute of the Russian Academy of SciencesMoscow 117186Russia

Single-phase 25 kV traction networks of electrified alternating current(AC)railways create electromagnetic fields(EMFs)with significant levels of *** most intense magnetic fields occur when short circuits exist between the contact wire and rails or *** the short duration of exposure,they can adversely affect electronic devices and induce significant voltages in adjacent power lines,which is dangerous for operating *** numerous investigations have focused on modeling the EMF of traction networks and power lines,the challenge of determining the three-dimensional electromagnetic fields near metal supports during the flow of a short-circuit current through them is yet to be *** this case,the field has a complex spatial structure that significantly complicates the calculations of *** study proposes a methodology,algorithms,software,and digital models for determining the EMF in the described emergency *** the modeling process,the objects being studied were represented by segments of thin wires to analyze the distribution of the electric charge and calculate the intensities of the electric and magnetic *** approach was implemented in the Fazonord software,and the modeling results show a substantial increase in EMF levels close to the support,with a noticeable decrease in the levels as the distance from it *** procedure implemented in the commercial software Fazonord is universal and can be used to determine electromagnetic fields at any electrical power facility that includes live parts of limited *** on the proposed procedure,the EMF near the supports of overhead power lines and traction networks of various designs could be determined,the EMF levels at substations can be calculated,and the influence of metal structures located near traction networks,such as pedestrian crossings at railway stations,can be considered.

关键词： Power supply systems AC railways Emergency conditions Electromagnetic fields near supports Modeling Electromagnetic safety

Theoretical Analysis of Cooperative Driving at Idealized Unsignalized Intersections

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Tsinghua Science and Technology 2024年第1期29卷 257-270页

作者： Shen Li Jiawei Zhang Zhenwu Chen Li Li department of Civil engineering Tsinghua UniversityBeijing 100084China department of Automation Tsinghua UniversityBeijing 100084China Shenzhen Urban transport Planning Center Co. Ltd.Shenzhen 518000China

Cooperative driving is widely viewed as a promising method to better utilize limited road resources and alleviate traffic *** recent years,several cooperative driving approaches for idealized traffic scenarios(i.e.,uniform vehicle arrivals,lengths,and speeds)have been ***,theoretical analyses and comparisons of these approaches are *** this study,we propose a unified group-by-group zipper-style movement model to describe different approaches synthetically and evaluate their *** derive the maximum throughput for cooperative driving plans of idealized unsignalized intersections and discuss how to minimize the delay of *** obtained conclusions shed light on future cooperative driving studies.

关键词： cooperative driving connected and automated vehicles unsignalized intersection

Effects of Atmospheric Pressure on Developmental Characteristics and the Stability of Air Entraining Agent for Concrete

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 979-989页

作者：李立辉牛开民 TIAN Bo CHEN Xin FU Ziqian ZHU Xuwei School of Civil engineering Chongqing Jiaotong UniversityChongqing 400074China transportation Science and engineering Harbin Institute of TechnologyHarbin 150090China Research Institute of Highway Ministry of TransportBeijing 100088China

In order to ascertain the effects of atmospheric pressure on developmental characteristics and the stability of AEA(air-entraining agent)solution bubbles,AEA solution experiments and AEA solution bubble experiments were,respectively,conducted in Peking(50 m,101.2 kPa)and Lhasa(3,650 m,63.1 kPa).Surface tensions and inflection-point concentrations were tested based on AEA solutions,whilst developmental characteristics,thicknesses and elastic coefficients of liquid films were tested based on air bubbles of AEA *** study involved three types of AEAs,which were TM-O,226A,and *** experimental results show that initial sizes of TM-O,226A,and 226S are,respectively,increased by 43.5%,17.5%,and 3.8%.With the decrease of ambient pressure,the drainage rate and the drainage index of AEA solution bubbles *** experiments show that the liquid film thicknesses of all tested AEA solution bubbles are in micron *** the atmospheric pressure decreases from 101.2 to 63.1 kPa,the liquid film thicknesses of three types of AEA solutions decrease in various degrees;and film elasticities at critical thicknesses *** film of 226S solution bubbles is the most stable,presenting as a minimum thickness *** should be noted that elastic coefficient of liquid film only represents the level at critical thickness,thus it can not be applied as the only evaluating indicator of bubble *** a type of AEA,factors affecting the stability of its bubbles under low atmospheric pressure include initial bubbles size,liquid film thickness,liquid film elasticity,ambient temperature,etc.

关键词： air-entraining agent surface tension bubble size liquid film thickness liquid film elasticity atmospheric pressure

Examining the characteristics between time and distance gaps of secondary crashes

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transportation Safety and Environment 2024年第1期6卷 116-131页

作者： Xinyuan Liu Jinjun Tang Chen Yuan Fan Gao Xizhi Ding Smart transport Key Laboratory of Hunan Province School of Transport and Transportation EngineeringCentral South UniversityChangsha 410075China department of Computer Science City University of Hong Kong999077Kowloon TongHong KongChina department of Geography and Resource Management The Chinese University of Hong KongShatinNT 999077Hong KongChina

Understanding the characteristics of time and distance gaps between the primary(PC)and secondary crashes(SC)is crucial for preventing SC ccurrences and improving road *** previous studies have tried to analyse the variation of gaps,there is limited evidence in quantifying the relationships between different gaps and various influential *** study proposed a two-layer stacking framework to discuss the time and distance ***,the framework took random forests(RF),gradient boosting decision tree(GBDT)and eXtreme gradient boosting as the base classifiers in the first layer and applied logistic regression(LR)as a combiner in the second *** this basis,the local interpretable model-agnostic explanations(LIME)technology was used to interpret the output of the stacking model from both local and global *** SC dentification and feature selection,346 SCs and 22 crash-related factors were collected from California interstate *** results showed that the stacking model outperformed base models evaluated by accuracy,precision,and recall *** explanations based on LIME suggest that collision type,distance,speed and volume are the critical features that affect the time and distance *** volume can prolong queue length and increase the distance gap from the SCs to *** collision types,peak periods,workday,truck involved and tow away likely induce a long-distance ***,there is a shorter distance gap when secondary roads run in the same direction and are close to the primary *** speed is a significant factor resulting in a long-time gap,while the higher speed is correlated with a short-time *** results are expected to provide insights into how contributory features affect the time and distance gaps and help decision-makers develop accurate decisions to prevent SCs.

关键词： secondary crash(SC) time and distance gaps stacking framework local interpretable model-agnostic explanations(LIME)

Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction

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Deep Underground Science and engineering 2024年第2期3卷 247-254页

作者： Shunyu Yue Ruifeng Miao Huihang Cheng Maohua Zhong Xiujun Yang department of engineering Physics Institute of Public Safety ResearchTsinghua UniversityBeijingChina Shanxi Province Expressway Group Limited Liability Company Shanxi Expressway Group Shuoshen Co. LtdShuozhouChina Research Institute of Highway Ministry of transport RIOH Transport ConsultantsLtdBeijingChina

The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea *** solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust *** order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were *** changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were *** this basis,the optimal smoke control strategy was proposed for different fire *** research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels.

关键词： sidewall smoke extraction system small‐scale fire tests smoke control

Accounting for Quadratic and Cubic Invariants in Continuum Mechanics–An Overview

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Fluid Dynamics & Materials Processing 2024年第9期20卷 1925-1939页

作者： Artur V.Dmitrenko Vladislav M.Ovsyannikov department of Physics National Research Nuclear University(MEPhI)Kashirskoye Shosse 31Moscow115409Russian Federation department of Thermal engineering and department of Waterways Ports and Hydraulic StructuresRussian University of Transport(MIIT)Obraztsova Street 9Moscow127994Russian Federation

The differential equations of continuum mechanics are the basis of an uncountable variety of phenomena and technological processes in fluid-dynamics and related *** equations contain derivatives of the first order with respect to *** derivation of the equations of continuum mechanics uses the limit transitions of the tendency of the volume increment and the time increment to *** are used to derive the wave *** differential wave equation is second order in ***,increments of volume and increments of time in continuum mechanics should be considered as small but finite quantities for problems of wave *** is important for calculating the generation of sound waves and water hammer ***,the Euler continuity equation with finite time increments is of *** finiteness of the time increment makes it possible to take into account the quadratic and cubic invariants of the strain rate *** is a new branch in *** and cubic invariants will be used in differential wave equations of the second and third order in time.

关键词： Quadratic invariant cubic invariant continuity equation generation of periodic waves N.E.Zhukovsky’s hydraulic shock turbulence

Synergistic effect of adsorption and photocatalytic degradation of oilfield-produced water by electrospun photocatalytic fibers of Polystyrene/Nanorod-Graphitic carbon nitride

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Journal of Environmental Sciences 2024年第7期141卷 287-303页

作者： Parisa Azmoon Mehrdad Farhadian Alireza Pendashteh Amir H.Navarchian department of Chemical engineering Faculty of EngineeringUniversity of IsfahanIsfahanIran department of Chemical engineering Faculty of EngineeringUniversity of GuilanRashtIran department of Water and Environmental engineering Caspian Sea Basin Research CenterUniversity of GuilanRashtIran

Graphitic carbon nitride with nanorod structure(Nr-GCN)was synthesized using melamine as a precursor without any other reagents by hydrothermal pretreatment ***,FTIR,SEM,N_(2)adsorption-desorption from BET,UV-Vis DRS spectroscopy,and photoluminescence were used to characterize the prepared ***,the photoelectrochemical behavior of nanoparticles was studied by photocurrent transient response and cyclic voltammetry ***(PS)fibrous mat was fabricated by electrospinning technique and used as a support for the stabilization of the *** performance of the synthesized nanoparticles and photocatalytic fibers(PS/Nr-GCN)was evaluated in oilfield-produced water treatment under visible light *** this process,oil contaminants were adsorbed by hydrophobic polystyrene fibers and simultaneously degraded by *** removal efficiency of chemical oxygen demand(COD)has been obtained 96.6%and 98.4%by Nr-GCN and PS/Nr-GCN,respectively,at the optimum conditions of pH4,photocatalyst dosage 0.5 g/L,COD initial concentration 550 mg/L,and illumination time 150 *** gas chromatography-mass spectroscopy analysis results showed 99.3%removal of total petroleum hydrocarbons using photocatalytic fibers of PS/*** results demonstrated that the GCN has outstanding features like controllable morphology,visible-light-driven,and showing high potential in oily wastewater ***,the synergistic effect of adsorption and photocatalytic degradation is an effective technique in oilfield-produced water treatment.

关键词： Graphitic carbon nitride(GCN) Nanorod structure Polystyrene fibrous mat Photocatalytic fibers Oilfield-produced water(OPW)

Underwater inertial error rectification with limited acoustic observations

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Satellite Navigation 2024年第1期5卷 207-223页

作者： Hongqiong Tang Hongyang He Fangneng Li Jiangning Xu department of Navigation engineering Naval University of EngineeringWuhan430000China

Underwater inertial navigation is particularly difficult for the long-durance operations as many navigation systems such global satellite navigation systems are *** acoustic signal is a marvelous choice for underwater inertial error rectification due to its underwater penetration ***,the traditional Acoustic Positioning Systems(APS)are expensive and incapable of positioning with limited acoustic *** novel underwater inertial error rectification algorithms with limited acoustic observations are *** first one is the single acoustic-beacon Range-only Matching Aided Navigation(RMAN)method,which is inspired by matching navigation without reference maps and presented for the first *** second is the improved single acoustic-beacon Virtual Long Baseline(VLBL)method,which considers the impact of indicated relative position increments on virtual beacon *** RMAN and improved VLBL are further developed when multi acoustic-beacons are available,named mAB-RMAN and *** comprehensive simulations and field investigations were *** results demonstrated that the proposed methods achieved excellent accuracy and stability compared to the baseline,specifically,the mAB-RMAN and mAB-VLBL can reduce the inertial error by more than 90%and 98%when using single and double acoustic-beacons,*** proposed techniques will provide new perspectives for underwater positioning,navigation,and timing.

关键词： Underwater PNT Range-only matching aided navigation Virtual long baseline Inertial error rectification

Artificial Intelligence Prediction of One-Part Geopolymer Compressive Strength for Sustainable Concrete

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Computer Modeling in engineering & Sciences 2024年第10期141卷 525-543页

作者： Mohamed Abdel-Mongy Mudassir Iqbal M.Farag Ahmed.M.Yosri Fahad Alsharari Saif Eldeen A.S.Yousef department of Civil engineering College of EngineeringJouf UniversitySakaka72388Saudi Arabia department of Civil engineering University of Engineering and TechnologyPeshawar54890Pakistan Civil engineering department Faculty of EngineeringAl-Azhar UniversityCairo11884Egypt Civil engineering department Faculty of EngineeringAswan UniversityAswan81528Egypt

Alkali-activated materials/geopolymer(AAMs),due to their low carbon emission content,have been the focus of recent studies on ecological *** terms of performance,fly ash and slag are preferredmaterials for precursors for developing a one-part ***,determining the optimum content of the input parameters to obtain adequate performance is quite challenging and scarcely ***,in this study,machine learning methods such as artificial neural networks(ANN)and gene expression programming(GEP)models were developed usingMATLAB and GeneXprotools,respectively,for the prediction of compressive strength under variable input materials and content for fly ash and slag-based one-part *** database for this study contains 171 points extracted from literature with input parameters:fly ash concentration,slag content,calcium hydroxide content,sodium oxide dose,water binder ratio,and curing *** performance of the two models was evaluated under various statistical indices,namely correlation coefficient(R),mean absolute error(MAE),and rootmean square error(RMSE).In terms of the strength prediction efficacy of a one-part geopolymer,ANN outperformed *** and parametric analysis were also performed to identify the significant contributor to *** to a sensitivity analysis,the activator and slag contents had the most effects on the compressive strength at 28 *** water binder ratio was shown to be directly connected to activator percentage,slag percentage,and calcium hydroxide percentage and inversely related to compressive strength at 28 days and curing temperature.

关键词： Artificial intelligence techniques one-part geopolymer artificial neural network gene expression modelling sustainable construction polymers