共查询到20条相似文献,搜索用时 15 毫秒
1.
Roger B. Trent Alon Kvashny Edward S. Neumann Elizabeth Walukas John Halkias 《先进运输杂志》1986,20(3):275-285
Research literature suggests that aesthetic response toward a transportation system may be colored by non-aesthetic values. Photographic depictions of downtown street scenes with and without automated people mover guideways were shown to various community groups. Measures of external utilities—stakes in the local community and in public transportation—bore no relationship to aesthetic assessments of either guideway scenes or street scenes without a guideway. In contrast, aesthetic background and interests depressed evaluations of both guideway and non-guideway scenes. Aesthetic background evidently influences aesthetic assessments of elevated guideways in urban streets far more than do non-aesthetic utilities. This suggests that planners of new transportation systems need to address aesthetic impacts apart from other impacts and that aesthetic criteria will be applied more stringently by some community groups than by others. 相似文献
2.
J. Edward Anderson 《先进运输杂志》2000,34(1):3-29
The paper begins with a review of the rational for development of personal rapid transit, the reasons it has taken so long to develop, and the process needed to develop it. Next I show how the PRT concept can be derived from a system‐significant equation for life‐cycle cost per passenger‐mile as the system that minimizes this quantity. In the bulk of the paper I discuss the state‐of‐the‐art of a series of technical issues that had to be resolved during the development of an optimum PRT design. These include capacity, switching, the issue of hanging vs. supported vehicles, guideways, vehicles, control, station operations, system operations, reliability, availability, dependability, safety, the calculation of curved guideways, operational simulation, power and energy. The paper concludes with a listing of the implications for a city that deploys an optimized PRT system. 相似文献
3.
Edward S. Neumann 《先进运输杂志》1999,33(1):51-82
The evolution of urban cable propelled people mover technology from the early 1800′s through the 1990′s is reviewed, with emphasis on systems developed since 1980. Technologies can be classified by the means of vehicle support and the type of service provided. The simplest systems serve as shuttles moving back-and-forth between a pair of terminal stations; more complex systems feature vehicles which are launched continuously at short headways. Advances have occurred in the design and aesthetics of guideways, vehicle operating speed, the spectrum of capacities available, and automated features. The characteristics of the individual systems in urban environments throughout the world are described. 相似文献
4.
A new transportation system is described. CyberTran is a steel wheel on rail system designed to travel on elevated guideways, utilizing large numbers of 6 to 20 passenger automated vehicles weighing less than 10,000 pounds. The benefits from these light weight vehicles include dramatically reduced system cost and increased passenger appeal. The system described has been prototyped and tested at the Idaho National Engineering and Environmental Laboratory, a U. S. Department of Energy Research and Development Laboratory. 相似文献
5.
Roger L. Tobin 《运输规划与技术》2013,36(4):215-223
This paper develops an analytic approach for measuring the effect of vehicle scheduling and of metering methods required to balance entrance rates among stations on lane capacity utilization of automated automobile guideways. The scheduling process at each entrance is represented by a probabilistic model which generates a system of nonlinear equations. The solution of this system yields the maximum steady state input rates at the entrances to the guideway system. The method developed is applicable to network configurations in which a small number of merges must be scheduled for each vehicle before it enters the guideway. It is demonstrated by application to a corridor guideway serving a major activity center during peak inbound demand, and also it is shown how the approach may be extended to more complex networks. 相似文献
6.
Elsa Rosenblad 《先进运输杂志》1998,32(1):35-44
The potential user interest in PRT's and the conditions for their use were studied. As users are unable to express certain opinions about technology they don't know, assessment studies must be close to real life. One way to getting close to reality is through studies in Virtual Reality (VR). Passenger encounters with PRT was studied by in-depth interviews directly after a VR-simulated trip in a real vehicle. The aims of using VR-technology seems to have been achieved. Many of the subjects had the impression of a real trip, some of them also of having travelled high above ground. All subjects were in favour of PRT and thought they would utilize it. They had confidence in the automatic control devices, although they wanted more information and better design of the safety system. The greatest conflict was the encroachment on the cityscape. Many of the subjects did not accept the impact of the guideways on the old city environment. However these views contrast with the desired accessibility. 相似文献
7.
Embedded concrete-lined corrugated steel (CLCS) has been widely used in many fields such as cutand- cover tunnels and shed-tunnels. However, fewer research works have been done about CLCS, and the contribution of corrugated steel (CS) to the bearing capacity of CLCS is not considered, causing a greater concrete lining thickness and higher cost. In this study, the reinforcement effect of CS was analyzed with numerical simulations by comparing the two models, in one of which the bearing capacity of CS was considered while the other was not. It is found that the stresses and deflections at the trough section are larger than that at the crest and middle parts; the maximum tensile stress of CLCS from the spandrel to the vault is approaching to the tensile strength and the deflection is higher; the maximum compressive stress of CLCS from the arch foot to the spandrel is close to the compressive strength and the deflection is lower. Moreover, it is an obvious reduction of the stresses and deflections at different sections and circumferential positions due to the contribution of CS. This indicates the reinforcement effect of CS should be taken into account to reduce lining thickness. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
8.
地下轨道交通暖通空调系统的优化设计与地下轨道交通隧道围岩的热物理参数性质密切相关。文章以兰州地下轨道交通原状土样为研究对象,使用Hot Disk热常数分析仪探究了兰州地下轨道交通围岩的热物理性质。研究结果表明:兰州地下轨道交通围岩土样的导热系数随深度的增加而增加,深度13 m处的中砂层导热系数和热扩散系数最大,明显比其它深度处的黄土层和淤泥质土层的导热系数和热扩散系数大,而中砂层体积比热较小;围岩土样的导热系数随含水率增加呈线性增长,体积比热随含水率增加先降低后增高,热扩散系数随含水率增加先升高后缓慢降低。 相似文献
9.
10.
随着使用年限的增长,预应力混凝土斜拉桥结构状态与安全问题越来越受到关注。文章针对具体实桥,进行荷载试验与应变监测,并根据设计与施工资料建立三维有限元模型对各施工阶段进行模拟。通过将模型计算值与实测挠度、应变与频率各参数对比,校正后得到反映桥梁实际工作状态的力学分析模型,以复核桥梁实际承载能力。结果表明,此方法实用可行。 相似文献
11.
Standards for fuel consumption and carbon dioxide emissions are implemented worldwide in most light-duty vehicle markets. Regulatory drive cycles, defined as specific time-speed patterns, are used to measure levels of fuel consumption and emissions. These measurements should realistically reflect real world driving performance, however there is increasing concern about their adequacy due to the discrepancies observed between certified and real world consumption and emissions values. One of the main reasons for the discrepancy is that current testing protocols do not account for non-mechanical vehicle energy needs, such as passengers’ thermal comfort needs and the use of electric auxiliaries on-board. Cabin heating and cooling can especially lead to considerable increase in vehicle energy consumption. This paper presents a simulation-based assessment framework to account for the additional fuel consumption related to the cabin thermal energy and auxiliary needs under the worldwide-harmonized light vehicles test procedure (WLTP). A vehicle cabin model is developed and the thermal comfort energy needs are derived for cooling and heating, depending on ambient external temperature under cold, moderate and warm climates. A modification to the WLTP is proposed by including the generated power profiles for thermal comfort and auxiliary needs. Dynamic programming is used to compute the fuel consumption on the modified WLTP for a rechargeable series hybrid electric vehicle (SHEV) architecture. Results show consumption increases of 20% to 96% compared to the currently adopted WLTP, depending on the considered climate. 相似文献
12.
13.
In this study, particulate matter was investigated as the primary pollutant in the air quality of Beijing Metro transfer stations, and passenger thermal comfort during the transfer process was evaluated by using the relative warmth index (RWI). Passenger thermal comfort level is not ideal in 87% of the measured space and is slightly hot overall, with an RWI range of 0.20–0.43. Although 20% of the measured space has lower values than ASHRAE’s cooling comfort class, the thermal comfort level of most measured space is good in winter morning rush hours, with an RWI range from −0.18 to 0.28. The particulate matter (PM) concentration is related not only to the season and spatial depth but also to the transfer design of the metro station. During the morning rush period, the concentration ranges difference of PM10 and PM2.5 in winter are 262.9 μg/m3 and 125.5 μg/m3, respectively, which are 1.43 and 1.46 times higher than those of in summer. There are significant differences in the PM concentration and RWI values between the island and lateral platforms of Beijing Metro transfer stations, and the design of the lateral platform is superior to that of the island platform. Another exploratory experiment is conducted to determine if the PM concentration has a potential effect on human metabolic rate. The data in this paper provide a valuable reference for further comfort research and environmental control in metro station, and the conclusions may guide the further underground space design of metro transfer stations. 相似文献
14.
This paper studies changes in people’s travel mode use from one year to the next. It is informed by three distinct discourses: travel behaviour change, the mobility biographies approach, and cohort analysis. The data used is the German Mobility Panel (GMP) 1994–2008 in which households and their members are asked three times in three subsequent years to report the trips they made over a week. The changes reported are regressed to key events over the life course, cohort effects and period effects, while various sociodemographic and spatial attributes are controlled. Due to the non-independent nature of panel observations, a cluster-robust regression approach is used. The findings suggest that behind the aggregate stability in travel mode use over time there is much change ‘under the surface’, induced by life course changes, individual and household sociodemographic, and spatial context. The changes found induced by life course related key events favour the notion of mobility biographies. However, taken over all key events seem to be relatively loosely associated with mode use changes. Nonetheless, various significant effects of baseline variables suggest that mode use may change even in the absence of a key event. 相似文献
15.
16.
17.
18.
文章通过对主要类型锂离子电池技术指标和特性进行梳理,研究了锂离子电池的热管理技术、安全性、火灾消防技术等应用重点环节的技术要点,分析了锂电池在船舶动力系统中的作用及全电池动力系统和混合动力系统的技术特点,为应用锂电池的新能源船舶研发提供参考。最后介绍了目前国内外应用储能电池动力船舶的多个典型案例,简要阐述了各个案例中的船舶核心参数和主要特点,总结了当前电池动力船舶的主要应用船型、锂电池类型、应用市场及政策、规范现状,认为锂电池动力船舶的发展前景光明,但在相关政策和船舶规范研究方面尚需进一步完善。 相似文献
19.
20.
文章针对砂砾地层电力顶管施工引起的地面变形开展研究。首先,基于现有散粒土的沉降理论计算公式,进行某砂砾地层电力隧道顶管施工引起地面变形的理论计算和分析;其次,通过理论分析和现场实测,得到砂砾地层顶管施工引起的地面变形规律;最后,在现有理论计算公式和监测数据的基础上,利用规划求解,提出适用于砂砾地层顶管施工引起地面变形的沉降槽宽度系数计算公式。研究结果表明,土体损失是引起地面沉降的主要影响因素,沉降计算时必须考虑土体损失在顶进过程中的动态变化;修正沉降槽宽度系数计算公式能够较好地适用于砂砾地层中顶管施工引起的地面沉降计算。 相似文献