Investigating the link between cyclist volumes and air pollution along bicycle facilities in a dense urban core

In this paper we explore the air pollution levels along types of bicycle facilities using a NO₂ land use model previously developed for Montreal. We explore potential associations between bicycle volumes through signalized intersections and pollution levels at those intersections. We further investigate this relationship through the comparison of over thirty cycling corridors as well as an evaluation of the potential exposure of cyclists to air pollution along five routes. We observe NO₂ concentrations to be positively correlated with bicycle flows at the intersection level. We also observe that corridors with either a bicycle path or cycle track generally rank higher in terms of bicycle volume and also have higher NO₂ concentrations than corridors without bicycle facilities. This indicates that intersections and bicycle facilities with a large number of cyclists are also those characterized with the highest air pollution levels.     

A review of the road safety strategy in hong kong

Since the mid-1990s, the effectiveness of road safety measures in Hong Kong has been weakening. Six administrations in Australia, California, Great Britain (GB), Japan, New Zealand and Sweden are selected to help review the road safety activities in Hong Kong. Nine main components of the road safety strategy, including vision, objectives, targets, action plan, evaluation and monitoring, research and development, quantitative modeling, institutional framework and funding are summarized from the road safety strategies of these overseas administrations and compared to that of Hong Kong. It is found that Hong Kong's road safety activities have to be restructured to make significant improvement. In the future, a new approach structured by the nine different road safety components is recommended. The lessons learnt can be generalized to smooth the progress of other administrations at the Intermediate Stage towards the Advanced Stage of road safety development by using the short-, medium- and long-term approaches.     

用于清管器收发球简上的新型快开门

介绍了一种适用于大口径、高压力管道用清管器收发球筒上的快开门机构.该快开门机构称为锁带嵌入式快开盲板.由直接承压部件(法兰型筒体及盲板盖)及其上的快速锁带收紧装置、安全卸压装置、特殊形式的密封圈及连接盲板盖与筒体的可微调转臂构成.该装置设计合理、动作灵活、操作简单、安全可靠,目前已少量生产并投入运行.     

Walking infrastructure design assessment by continuous space dynamic assignment modeling

For the planning and design of walking infrastructure, characterized by the fact that the pedestrians can choose their paths freely in two‐dimensional space, applicability of traditional discrete network models is limited. This contribution puts forward an approach for user‐optimal dynamic assignment in continuous time and space for analyzing for instance walking infrastructure in a two‐dimensional space. Contrary to network‐based approaches, the theory allows the traffic units to choose from an infinite non‐countable set of paths through the considered space. The approach first determines the continuous paths using a path choice model. Then, origin‐destination flows are assigned and traffic conditions are calculated. The approach to determine a user‐optimal assignment is heuristic and consists of a sequence of all‐or‐nothing assignments. An application example is presented, showing dynamic user equilibrium traffic flows through a realistic transfer station. The example is aimed at illustrating the dynamic aspects of the modeling approach, such as anticipation on expected flow conditions, and predicted behavior upon catching or missing a connection.     

Multimodal traveling and its impact on urban transit network design

Multimodal trip making, that is trips using a combination of several modes between origin and destination, is expected to be beneficial to society and might offer advantages to the traveler as well. This article looks at some of the implications of multi‐modality in trip making for the design of urban transit systems since these play an important role in multi‐modal transportation systems. In this respect, the article looks at the strategic design characteristics of urban transit networks, that is line density, stop density and service frequencies for the case of multimodal access to urban transit networks and for hierarchical network structures in urban transit systems. The analyses show that multimodal access does not require alternative network structures. For hierarchical network structures it is concluded that these are primarily determined by the hierarchy in demand densities and thus by hierarchy in urban structures.     

Application of time series techniques for forecasting truck traffic attracted by the Bombay metropolitan region

Knowledge of future traffic flow is an essential input in the planning, implementation and development of a transportation system. It also helps in its operation, management and control. Time series analysis techniques have been extensively adopted for this purpose in the fields of economics, social sciences and in other fields of technology. An attempt has been made in this study to apply the techniques of time series analysis to goods traffic, particularly truck traffic. Four predominant corridors, N.H.3, N.H.4, N.H.8 and Lal Bahadur Shastri Road (L.B. S. Rd.), accounting for majority of truck movement in the Bombay Metropolitan Region (BMR), have been considered for modeling. Raw data was processed initially, to obtain an insight into the structure of time series. Ten candidate models of the Auto-Regressive Moving Average (ARMA) and Auto-Regressive Integrated Moving Average (ARIMA) family are investigated to represent each of the four corridors. Models finally proposed, to represent each of the four corridors have been selected based on Minimum Mean Square Error (MMSE) and Maximum Likelihood Rule (MLR) criteria. Models ARIMA (2, 1, 0), ARMA (1.0), ARMA (1, 1) and ARIMA (1, 1, 0) are proposed for N.H.3, N.H.4, N.H.8 and L.B.S. Rd. respectively, based on significant weekly periodicity.     

京张高铁八达岭长城站大跨度深埋三连拱隧道设计及施工方法研究

目前三连拱隧道衬砌荷载尚无成熟的计算方法且类似工程施工经验相对较少,以京张高铁八达岭长城站为例,研究在V级围岩地质条件下,大跨度深埋三连拱隧道设计计算方法及合理的施工工序。依据普氏平衡拱理论并借鉴双连拱隧道围岩荷载计算方法,提出深埋三连拱隧道围岩荷载模型,通过建立有限元模型,分析三连拱隧道的合理施工工序。研究表明:三连拱隧道围岩压力可以看作拱部松散土压力及中隔墙所承受的压力之和;三连拱施工工序推荐采用先侧洞后中洞的工序,对于施工过程中保持围岩及支护结构体系的稳定较为有利;通过右洞围岩压力计算结果与现场检测结果对比分析,围岩压力最大相对误差在10%以内,全施工阶段监测情况一切正常,验证了解析法计算结果的合理性及施工工序的优越性。     

�����еĶ�ά����ģ�ⷽ��Ӧ������

由于在模拟密集网络、宏观问题和方案阶段中的优势,连续性模拟方法应用到交通模型的模拟中,正在得到越来越多的关注。此论文意在为二维连续模拟方法的发展和应用提供综合的概括。首先讨论的是理论的发展和对特殊的或多变领域机理的模拟,然后再针对连续模拟方法应用到工厂选址、道路选择、人行道的规划、政策和社会经济分析进行评论。最后,预测其未来研究的前景。     

碱激发粉煤灰-矿渣基煤矸石透水混凝土制备及性能研究

为弥补煤矸石透水混凝土强度缺陷,加强煤矸石在透水混凝土中的资源化利用。以碱激发粉煤灰-矿渣胶凝材料替代水泥,煤矸石取代部分天然粗骨料,制备碱激发粉煤灰-矿渣基煤矸石透水混凝土(AFSGPC)。通过正交试验和极差分析,探究骨料级配、煤矸石取代率、水胶比、碱激发剂模数、目标孔隙率5个因素对AFSGPC力学性能和透水性能的影响程度;基于正交试验得到的基准配合比设计单因素优化试验,研究影响程度最显著的3个因素对AFSGPC力学性能和透水性能的作用效应及其机理,并确定最优配合比;结合X-射线衍射(XRD)、扫描电子显微镜(SEM)和能量色散光谱(EDS)分析AFSGPC的矿物成分变化和微观形貌。研究结果表明：正交试验下AFSGPC的28 d抗压强度最大值为22.59 MPa,此时的劈裂抗拉强度为2.62 MPa,透水系数为2.41 mm/s,有效孔隙率为19.7%;影响AFSGPC基本性能最显著的3个因素为煤矸石取代率、水胶比和目标孔隙率;基于这3个显著因素优化后的配合比为：采用5～10 mm单级配骨料,煤矸石取代率为35%,水胶比为0.32,碱激发剂模数为1,目标孔隙率为15%,该配合比能够在满足透水混凝土路用规范要求的前提下最大程度利用煤矸石;AFSGPC力学性能的提升主要得益于碱激发粉煤灰-矿渣胶凝材料高强度、高黏性特性以及胶凝材料对界面过渡区结构的改善。研究结果可为AFSGPC的制备及其工程应用提供一定的参考。