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Future urban transport management

《工程管理前沿（英文）》页码 534-539 doi: 10.1007/s42524-023-0255-3

摘要： The incorporation of disruptive innovations into the transportation industry will inevitably cause major upheavals in the transportation sector. However, existing research lacks systematic theories and methodologies to represent the underlying characteristics of future urban transport systems. Furthermore, emerging modes in urban mobility have not been sufficiently studied. The National Natural Science Foundation of China (NSFC) officially approved the Basic Science Center project titled “Future Urban Transport Management” in 2022. The project members include leading scientists and engineers from Beijing Jiaotong University, Beihang University, and Beijing Transport Institute. Based on a wide range of previous projects by the consortium on urban mobility and sustainable cities, this project will encompass transdisciplinary and interdisciplinary research to explore critical issues affecting future urban traffic management. It aims to develop fundamental theories and methods based on social and technological developments in the near future and explores innovative solutions to implement alongside these emerging developments in urban mobility.

关键词： future urban transport management travel behavior characteristics transportation operations transportation emergency management transportation decision intelligence

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Understanding network travel time reliability with on-demand ride service data

Xiqun (Michael) CHEN, Xiaowei CHEN, Hongyu ZHENG, Chuqiao CHEN

《工程管理前沿（英文）》 2017年第4卷第4期页码 388-398 doi: 10.15302/J-FEM-2017046

摘要： Travel time reliability is of increasing importance for travelers, shippers, and transportation managers because traffic congestion has become worse in major urban areas in recent years. To better evaluate the urban network-wide travel time reliability, five indices based on the emerging on-demand ride service data are proposed: network free flow time rate (NFFTR), network travel time rate (NTTR), network planning time rate (NPTR), network buffer time rate (NBTR), and network buffer time rate index (NBTRI). These indices take into account the probability distribution of the travel time rate (i.e., travel time spent for the unit distance, in min/km) of each origin-destination (OD) pair in the road network. We use real-world data extracted from DiDi-Chuxing, which is the largest on-demand ride service platform in China. For demonstrative purposes, the network-wide travel time reliability of Beijing is analyzed in detail from two dimensions of time and space. The results show that the road network is more unreliable in AM/PM peaks than other time periods, and the most reliable time period is the early morning. Additionally, we can find that the central region is more unreliable than other regions of the city based on the spatial analysis results. The proposed network travel time reliability indices provide insights for the comprehensive evaluation of the road network traffic dynamics and day-to-day travel time variations.

关键词： network travel time reliability on-demand ride services travel time rate OD

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Pyrene partition behavior to the NOM: Effect of NOM characteristics and its modification by ozone preoxidation

Jin GUO, Jun MA

《环境科学与工程前沿（英文）》 2009年第3卷第1期页码 56-61 doi: 10.1007/s11783-009-0003-x

摘要： Hydrophobic organic contaminants (HOCs)—pyrene, and natural organic matters (NOM) from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’ partition to the NOM in this study. The effects of solution property, NOM characteristics, and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated. According to the fluorescence quenching method, the partition coefficient of pyrene to NOM was calculated, which was found to have a great relationship with the aromatic structures and hydrophobic functional groups of the NOM. The NOM characteristic modification corresponding to solution property could influence the interactions between the NOM and pyrene. Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease of pyrene.

关键词： natural organic matters (NOM) pyrene partition coefficient ozone

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Effect of anisotropic characteristics on the mechanical behavior of asphalt concrete overlay

Lingyun YOU, Zhanping YOU, Kezhen YAN

《结构与土木工程前沿（英文）》 2019年第13卷第1期页码 110-122 doi: 10.1007/s11709-018-0476-4

摘要： Asphalt concrete (AC) overlays placed over old asphalt pavement have become an alternative to repairing and reinforcing pavements. The strength contributed by the AC overlay is strongly influenced by the anisotropic properties of the pavement material. This study was conducted to analyze the influence of anisotropy, modulus gradient properties, and the condition of the AC overlay and old pavement contact plane on the mechanical behaviors of AC overlays, as well as to quantify the influence of the degree of anisotropy on the mechanical behaviors of AC overlay by a sensitivity analysis (SA). The mechanical behaviors of the AC overlay were numerically obtained using the three-dimensional finite element method with the aid of ABAQUS a commercial program. Variations in the AC overlay’s modulus as a function of temperature as well as the contact state between the AC overlay and AC layer were considered. The SA is based on standardized regression coefficients method. Comparing the mechanical behavior in terms of surface deflection, stress, and strain of the anisotropy model against those corresponding to the isotropic model under static loads show that the anisotropic properties had greater effects on the mechanical behavior of the AC overlay. In addition, the maximum shear stress in the AC overlay was the most significant output parameter affected by the degree of anisotropy. Therefore, future research concerning the reinforcement and repair of pavements should consider the anisotropic properties of the pavement materials.

关键词： asphalt concrete overlay anisotropy temperature gradients modulus gradients finite element simulation sensitivity analysis

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Appraisal of coastal recreational resources in Qingdao by travel cost method

Jingmei LI , Tieying LIU , Yuanyuan ZHANG , Lei LI ,

《环境科学与工程前沿（英文）》 2009年第3卷第3期页码 341-347 doi: 10.1007/s11783-009-0038-z

摘要： This paper serves to appraise the monetary cost of coastal recreational resources in Qingdao using the travel cost method (TCM), which is typically used in developed countries. The total revenue produced by Qingdao’s coastal recreational resources is about RMB 5.51×10 annually, based on questionnaires given at Qingdao’s major tourist destinations. These questionnaires establish correlation functions that factor in the number of tourists, travel expenses, etc. The data processing software named Eviews was used to determine the tourist demand regression curve and to calculate their residual and actual travel expenses. The results of this study can provide a scientific basis for applicable industries interested in development and management decision-making. Therefore, this study assesses the reasonable usage of coastal recreational resources.

关键词： coastal recreational resources travel cost method (TCM) regression analysis Qingdao China

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Characteristics of the stabilized/solidified municipal solid wastes incineration fly ash and the leachingbehavior of Cr and Pb

Yan SHAO,Haobo HOU,Guangxing WANG,Sha WAN,Min ZHOU

《环境科学与工程前沿（英文）》 2016年第10卷第1期页码 192-200 doi: 10.1007/s11783-014-0719-0

摘要： Fly ash is a hazardous byproduct of municipal solid wastes incineration (MSWI). An alkali activated blast furnace slag-based cementitious material was used to stabilize/solidify the fly ash at experimental level. The characteristics of the stabilized/solidified fly ash, including metal leachability, mineralogical characteristics and the distributions of metals in matrices, were tested by toxic characteristic leaching procedure (TCLP), X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) respectively. Continuous acid extraction was utilized to extract metal ions and characterize their leaching behavior. The stabilization/solidification procedure for MSWI fly ash demonstrates a strong fixing capacity for the metals by the formation of C-S-H phase, hydrated calcium aluminosilicate and ettringite. The stabilized/solidified fly ash shows a dense and homogeneous microstructure. Cr is mainly solidified in hydrated calcium aluminosilicate, C-S-H and ettringite phase through physical encapsulation, precipitation, adsorption or substitution mechanisms, and Pb is mainly solidified in C-S-H phase and absorbed in the Si-O structure.

关键词： municipal solid waste incineration (MSWI) fly ash blast furnace slag leaching behavior Cr Pb

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Charge and separation characteristics of nanofiltration membrane embracing dissociated functional groups

Zhun MA,Meng WANG,Xueli GAO,Congjie GAO

《环境科学与工程前沿（英文）》 2014年第8卷第5期页码 650-658 doi: 10.1007/s11783-013-0605-1

摘要： The current work focused on the investigation of charge and separation characteristics of nanofiltration (NF) membrane embracing dissociated functional groups under different electrolyte solutions. The electro-kinetic method was carried out to assess the membrane volume charge density ( ) with different salt concentrations ranging from 0.1 to 10 mol·m and different electrolyte species, such as type 1–1, type 2–1 and type 3–1. The Donnan steric pore model-dielectric exclusion (DSPM-DE) model was employed to evaluate the separation characteristics of the NF membrane for wide range of electrolyte concentration (from 25.7 to 598.9 mol·m ). The results indicated that the dissociation of the hydrophilic functional groups and the specific adsorption contributed to charge formation on membrane surface. The former played a dominant role in type 1–1 and type 2–1 electrolytes at dilute aqueous solutions (0.1–0.5 mol·m ). However, for type 3–1 electrolyte, specific adsorption should contribute to the charge effect to a large extent. Moreover, the correlation between the volume charge density and feed concentration was in accordance with Freundlich isotherm. Furthermore, it was found that the separation characteristic of NF membrane could be evaluated well by DSPM-DE model coupling with electro-kinetic method in a whole concentration range.

关键词： Sulfonated polyethersulfone nanofiltration membrane charge characteristics electro-kinetic method volume charge density separation behavior

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Characteristics of pollutants behavior in a stormwater constructed wetland during dry days

Jianghua YU, Kisoo PARK, Youngchul KIM

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 649-657 doi: 10.1007/s11783-012-0426-7

摘要： A stormwater wetland treating non-point source pollution (NPS) from a 64 ha agricultural watershed was monitored over a period of five months. The results indicated that pH and dissolved oxygen (DO) were increased in the wetland due to the algal growth. The highest total suspended solids (TSS) concentration was observed in the aeration pond due to the resuspension of solids, decreased in the wetland. The respective decreases in total nitrogen (TN) and total kjeldahl nitrogen (TKN) were 15.9% and 28.7% on passing through the wetland. The nitrate and ammonia were increased by 45.4% and decreased by 79.9%, respectively. These variations provided strong evidence for the existence of nitrification. The total phosphorus (TP) and phosphate had respective reductions of 52.3% and 58.2% over the wetland. The total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) were also decreased. Generally, the TN, TP and phosphate removal efficiencies were positive. These positive removal efficiencies were mainly due to microbial activities, uptake by plants, and chemical precipitation at high pH. Negative removal efficiencies can be caused by continuous rainfall activities, with short antecedent dry days (ADDs) and unstable hydraulic conditions, some other biogeochemical transformations and algal growth also being important parameters.

关键词： constructed stormwater wetland dry days nitrification and denitrification pollutants characteristic

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Mechatronic design of a novel linear compliant positioning stage with large travel range and high out-of-plane

Hua LIU, Xin XIE, Ruoyu TAN, Lianchao ZHANG, Dapeng FAN

《机械工程前沿（英文）》 2017年第12卷第2期页码 265-278 doi: 10.1007/s11465-017-0453-y

摘要：

Most of the XY positioning stages proposed in previous studies are mainly designed by considering only a single performance indicator of the stage. As a result, the other performance indicators are relatively weak. In this study, a 2-degree-of-freedom linear compliant positioning stage (LCPS) is developed by mechatronic design to balance the interacting performance indicators and realize the desired positioning stage. The key parameters and the coupling of the structure and actuators are completely considered in the design. The LCPS consists of four voice coil motors (VCMs), which are conformally designed for compactness, and six spatial leaf spring parallelograms. These parallelograms are serially connected for a large travel range and a high out-of-plane payload capacity. The mechatronic model is established by matrix structural analysis for structural modeling and by Kirchhoff’s law for the VCMs. The sensitivities of the key parameters are analyzed, and the design parameters are subsequently determined. The analytical model of the stage is confirmed by experiments. The stage has a travel range of 4.4 mm× 7.0 mm and a 0.16% area ratio of workspace to the outer dimension of the stage. The values of these performance indicators are greater than those of any existing stage reported in the literature. The closed-loop bandwidth is 9.5 Hz in both working directions. The stage can track a circular trajectory with a radius of 1.5 mm, with 40 mm error and a resolution of lower than 3 mm. The results of payload tests indicate that the stage has at least 20 kg out-of-plane payload capacity.

关键词： mechatronic design linear compliant positioning stage large travel range high out-of-plane payload capacity spatial parallelogram voice coil motor sensitivity analysis

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Middle East respiratory syndrome coronavirus: current situation and travel-associated concerns

null

《医学前沿（英文）》 2016年第10卷第2期页码 111-119 doi: 10.1007/s11684-016-0446-y

摘要：

The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 brought back memories of the occurrence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002. More than 1500 MERS-CoV cases were recorded in 42 months with a case fatality rate (CFR) of 40%. Meanwhile, 8000 cases of SARS-CoV were confirmed in six months with a CFR of 10%. The clinical presentation of MERS-CoV ranges from mild and non-specific presentation to progressive and severe pneumonia. No predictive signs or symptoms exist to differentiate MERS-CoV from community-acquired pneumonia in hospitalized patients. An apparent heterogeneity was observed in transmission. Most MERS-CoV cases were secondary to large outbreaks in healthcare settings. These cases were secondary to community-acquired cases, which may also cause family outbreaks. Travel-associated MERS infection remains low. However, the virus exhibited a clear tendency to cause large outbreaks outside the Arabian Peninsula as exemplified by the outbreak in the Republic of Korea. In this review, we summarize the current knowledge about MERS-CoV and highlight travel-related issues.

关键词： coronavirus MERS Middle East respiratory syndrome

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超声速客机计划再次登上历史舞台

Sean O’Neill

《工程（英文）》 2022年第10卷第3期页码 1-3 doi: 10.1016/j.eng.2022.01.004

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Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

《结构与土木工程前沿（英文）》 2012年第6卷第3期页码 210-216 doi: 10.1007/s11709-012-0165-7

摘要： A uniaxial tension test is commonly used to determine the mechanical properties of steel, but it has no meaning for the response of the material in a structure. The test was developed as a consensus solution by producers, fabricators, designers and code writers, to have a standard by which similar materials could be compared to a common base. It does not represent the actual behavior of the steel in a structure, and was never intended to do so. To study the true behavior of the structure and how the material responds it would be better to determine the strains and deformations that will take place during actual service condition. Such characteristics reflect the real behavior, whether in the elastic or inelastic range. If stresses or forces are needed, these are easily determined by the value of the strain and the relevant material modulus, along with the type of cross section, whether elastic or inelastic. The paper addresses the properties of a range of structural steels, how these are incorporated into design standards and how the standards define deformation characteristics and demands for bolted and welded connections.

关键词： steel stress-strain characteristics tension test strain design actual behavior improved design codes

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全球旅行和接触限制对减缓COVID-19 疫情大流行作用的评估 Article

赖圣杰, Nick W. Ruktanonchai, Alessandra Carioli, Corrine W. Ruktanonchai, Jessica R. Floyd, Olivia Prosper, 张弛, 杜向军, 杨维中, Andrew J. Tatem

《工程（英文）》 2021年第7卷第7期页码 914-923 doi: 10.1016/j.eng.2021.03.017

摘要：

为了减缓新冠病毒肺炎（COVID-19）疫情的大流行，全球已广泛实施了旅行限制和保持社交距离的措施，但这些干预措施在不同地区和时间方面的有效性尚待深入研究。基于2020年第一波疫情期间135个国家或地区手机定位数据获得的人口流动指标，我们构建了一个元人口流行病学模型（metapopulation epidemiological model），用于评估全球旅行和接触限制对遏制不同地区COVID-19传播的影响。研究发现，如果未采取这些干预措施，截至2020年5月31日，研究地区（135个国家或地区）的累计COVID-19病例数可能已增加97倍（四分位距为79~116）。然而，这些措施的有效性取决于干预的及时性、强度和持续时长，并且不同人群、地区和季节的发病严重程度有所差异。此外，本研究结果强调，在放松干预措施期间，并且在有效的疫苗普及和实现群体免疫之前，在一定程度上，仍需采取减少人员接触的措施，以避免下一波疫情的快速出现和再次采取全面封锁措施。

关键词： COVID-19 大流行人口流动旅行限制保持社交距离

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Study on Big Data-based Behavior Modification in Metro Construction

Lie-yun Ding,Sheng-yu Guo

《工程管理前沿（英文）》 2015年第2卷第2期页码 131-136 doi: 10.15302/J-FEM-2015037

摘要： With the rapid development of metro construction in China, construction accidents frequently happen, which are significantly attributable to workers’ unsafe behavior. Behavior-based safety (BBS) is an effective method to modify workers’ unsafe behavior. This paper introduces the study on big data-based metro construction behavior modification, aiming to solve the problem of current research without consideration of workers’ personal characters. First, the behavior modification pushing mechanism based on content-based personalized recommendation is studied. Secondly, the development of behavior modification system of metro construction (BMSMC) is introduced. Thirdly, BMSMC practical applications using the unsafe behavior rate, as a measuring indicator is implemented. Observations at one metro construction site in Wuhan indicate that the unsafe behavior rate of modified scaffolders at this work place decreased by 69.3%. At the same time, as of unmodified scaffolders at another work place for comparison, the unsafe behavior rate decreased by 56.9%, which validates the effectiveness of this system.

关键词： big data unsafe behavior behavior modification behavior-based safety (BBS) unsafe behavior rate

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Flow behavior of non-spherical particle flowing in hopper

He TAO,Wenqi ZHONG,Baosheng JIN

《能源前沿（英文）》 2014年第8卷第3期页码 315-321 doi: 10.1007/s11708-014-0331-9

摘要： Ellipsoidal particles flowing in the hopper were simulated by using the discrete element method (DEM), and described by the multi-element method. The contact detection algorithm and equations for ellipsoidal particle motion in hopper were developed. And the simulation results were confirmed by experiment. Additionally, the mass flow rate, pressure distribution and velocity distribution of two kinds of particles were examined. The results show that the mass flow rate of ellipsoidal particles is smaller than that of spherical particles. There is a maximum value of pressure drop at the top of the junction. Besides, the pressure drop decreases with the discharging time increasing. The velocity of spherical particle is larger than that of ellipsoidal.

关键词： discrete element method ellipsoidal particle flow behavior hopper