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751.
Kenyon C. Lindeman Lauren E. Dame Christine B. Avenarius Benjamin P. Horton Jeffrey P. Donnelly D. Reide Corbett 《Coastal management》2015,43(5):555-574
To identify priority information needs for sea-level rise planning, we conducted workshops in Florida, North Carolina, and Massachusetts in the summer of 2012. Attendees represented professionals from five stakeholder groups: federal and state governments, local governments, universities, businesses, and nongovernmental organizations. Over 100 people attended and 96 participated in breakout groups. Text analysis was used to organize and extract most frequently occurring content from 16 total breakout groups. The most frequent key words/phrases were identified among priority topics within five themes: analytic tools, communications, land use, ecosystem management, and economics. Diverse technical and communication tools were identified to help effectively plan for change. In many communities, planning has not formally begun. Attendees sought advanced prediction tools yet simple messaging for decision-makers facing politically challenging planning questions. High frequency key words/phrases involved fine spatial scales and temporal scales of less than 50 years. Many needs involved communications and the phrase “simple messaging” appeared with the highest frequency. There was some evidence of geographic variation among regions. North Carolina breakout groups had a higher frequency of key words/phrases involving land use. The results reflect challenges and tractable opportunities for planning beyond current, geophysically brief, time scales (e.g., election cycles and mortgage periods). 相似文献
752.
本文研究了冷补沥青与基质沥青的基本性能和粘度的变化,进而得出冷补沥青的粘温曲线,指出冷补沥青的最佳拌合温度;基于沥青与集料的粘附力、液体表面张力理论以及沥青与集料接触角理论,通过接触角分析仪和表面张力仪试验测定冷补沥青与集料接触角、冷补沥青表面张力等数据,应用冷补沥青与集料的粘附功来定量地评价两者间的粘附性程度;为有效控制柴油型全天候冷补沥青的质量,根据大量试验结果和分析,制定出冷补沥青性能特性指标. 相似文献
753.
R. Conti E. Galardi E. Meli D. Nocciolini A. Rindi 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(5):651-671
Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components. 相似文献
754.
为在外海无掩护恶劣环境下安全、高效施工,开发了高桩墩台,采用预制安装与现浇相结合施工的新工艺.详细介绍施工方案的选择.新工艺投入使用后,大大缩短施工工期,减少海上施工费用. 相似文献
755.
Abstract The objective of this research is to develop and test a framework for efficiency assessment of road safety measures and evaluate its use in decision‐making. An exhaustive review of standard methodologies and practices related to cost‐effectiveness and cost–benefit analyses is carried out for that purpose. Moreover, a number of case studies are performed, concerning the efficiency assessment of various road safety measures in different countries, covering different types of road safety measures (user‐, vehicle‐ or infrastructure‐oriented, policy or enforcement, etc.), ranging from national to local levels of implementation and including both ex ante and ex post evaluations. From the results conclusions are drawn on the efficiency of different road safety measures and the related determinants. Furthermore, the case studies reveal a number of methodology and data issues for which further research is required. The procedures and barriers involved in the use of efficiency assessment techniques at different levels of decision‐making are also highlighted by means of feedback received during and after the various case studies. On the basis of these results, a framework for the promotion, implementation and evaluation of efficiency assessment in road safety decision‐making is proposed. A particular set of recommendations is also presented regarding the treatment of barriers (fundamental, institutional or technical) within the efficiency assessment itself and the related decision‐making process. 相似文献
756.
AbstractWe review a number of theories of motivation, and typologies of motivations, in psychological theory and in application to a variety of specific contexts, including shopping, eating, leisure, tourism, and travel. A recurring theme is the distinction between extrinsic (instrumental, utilitarian, functional) and intrinsic (autotelic, hedonic, experiential) motivations. We suggest that travel is a behavior to which intrinsic motivations apply, and that focusing exclusively on the extrinsic motivations to travel runs the risk of substantially underestimating the demand for travel, and the resistance to policies attempting to reduce it or to technologies (notably, information and communication technologies) expected to (partly) replace it. We offer a number of suggestions for improving standard travel surveys to help obtain the data needed to explore intrinsic motivations more fully. As better data become available, travel behavior models can be refined to partly account for such motivations. We believe that the resulting insights will be extremely valuable to policy-makers, planners, and behavioral scholars. 相似文献
757.
P.E. Canning S.J. Hughes E.E. Hellawell B.C.M. Gatersleben C.J. Fairhead 《运输规划与技术》2013,36(8):733-745
Abstract Carpooling, the process by which individuals share a private vehicle for a particular journey or journeys, has been undertaken both formally and informally for a great number of years. A variety of computational methods for undertaking the ‘ride-matching’ element for the formation of carpools have been developed and subsequently made into integrated tools to allow the formation of multiple carpools. Such tools are commonly used by both Local Authorities and employers who are looking to establish and operate their own formal carpool scheme, increasingly using a web-based interface. The aim of this paper is to understand how users enrolled with employer-led carpool schemes perceive the importance of several different factors in their decision to participate. It is a further aim to determine the importance they attach to employer provided priority parking spaces. A survey-based approach investigates the perceptions of users from six different employer operated carpool schemes in the UK. The paper suggests that saving money was perceived as the most important reason for an individual's decision to use a formal employer-led carpool scheme – even amongst carpool schemes where the employer provides significant incentives to participate. No regular access to their own vehicle and ‘more sociable travel’ were generally perceived as less important reasons to participate. For employers who offer priority parking to carpoolers, this was generally valued as important by participants, even when the employment location did not have significant parking pressures. 相似文献
758.
ABSTRACTThis narrative review synthesised the limited work that has been carried out into road safety education targeting parents. Parent education appeared to have a positive impact on child safety seat use and children’s bike helmet use, but results regarding the impact of parent education on pedestrian safety were mixed. The review highlighted important gaps in the literature. A key gap being identifying effective ways to engage parents of low socioeconomic and ethnic minority backgrounds. Further, another gap is understanding effective ways to engage and support parents of children with additional needs to build their children’s road safety skills. There is some evidence that parent education has a positive impact on these “at-risk” groups, but little work on how to engage with these groups and the type of parent education required. 相似文献
759.
I. Youn M. A. Khan N. Uddin E. Youn M. Tomizuka 《International Journal of Automotive Technology》2017,18(2):307-316
This research investigates stochastic estimation of a look-ahead sensor scheme using the optimal preview control for an active suspension system of a full tracked vehicle (FTV). In this scheme, wheel disturbance input to the front wheels are estimated using the dynamic equations of the system. The estimated road disturbance input at the front wheels are utilized as preview information for the control of subsequently following wheels of FTV. The design of optimal preview control is used as a classical linear quadratic Gaussian problem by combining dynamics of the original system and estimation of previewed road inputs. The effectiveness of the preview controller is evaluated by comparing the estimated information with the measured information for different road profiles, where Kalman filter is used for the state-variables estimation of the FTV. This research also considers the reduced order estimation using commonly available sensors in order to decrease the number of sensors and measurements. The simulation results’ using an active suspension system with different preview information shows that the proposed system can be beneficial for the improvement of ride comfort of tracked vehicles without using any specialized sensors for preview information calculation. 相似文献
760.
Y. Bai L. Y. Fan X. Z. Ma H. L. Peng E. Z. Song 《International Journal of Automotive Technology》2016,17(4):567-579
In this paper, the bond graph model of common rail injector was proposed in consideration of the effects of variable liquid capacitance and fuel physical property on the injection characteristics of the injector. State equations were derived based on the model, which were numerically solved by programming in Matlab. Comparisons between the simulation results and the experimental data show that the numerical model can effectively predict the injection quantity of the system. Effect of variation of delivery chamber diameter, needle seat semi-angle, needle cone semi-angle, ball valve seat semi-angle, nozzle hole diameter, inlet orifice diameter and outlet orifice diameter on fuel injection quantity had been analyzed. The influence rules of various parameters on the fuel injection quantity had been established. The experiments were conducted using face centered central composite design. A second order polynomial response surface model had been developed for predicting fuel injection quantity, as a function of the independent variables. Analysis of variation was used to determine the significance interactions which primarily affect the fuel injection quantity. It had been concluded that six interaction factors including delivery chamber diameter with nozzle hole diameter, needle seat semi-angle with needle cone semi-angle, needle seat semi-angle with nozzle hole diameter, needle cone semi-angle with nozzle hole diameter, nozzle hole diameter with inlet orifice diameter, and nozzle hole diameter with outlet orifice diameter have significant effect on the fuel injection quantity of the system. 相似文献