沥青混凝土路面平整度差的成因及对策研究

结合G205、G312等沥青路面不同程度出现的沉陷、接缝台阶、波浪、车辙、桥涵与路面接茬不平、跳车等路面不平整现象,分析、探讨造成沥青路面平整度差的路基、桥涵、路面基层施工方面、材料方面以及路面摊铺、碾压等主要原因,并提出相应对策措施。     

The contribution of road traffic to particulate matter and metals in air pollution in the vicinity of an urban road

A detailed investigation was conducted to study the sources of particulate matter in the vicinity of an urban road in Žilina. To determine the amount of particulate matter (PM₁₀, PM_2.5 and PM₁) present in the ambient air, a reference gravimetric method was used. The main objective of this contribution was to identify the sources of these particles by means of statistical methods, specifically principal component analysis (PCA), factor analysis (FA), and absolute principal component scores (APCS), as well as using the presence of 17 metals in the particulate matter (Na, Mg, Al, Ca, V, Cr, Fe, Mn, Ni, Cu, Zn, As, Mo, Sb, Cd, Ba, Pb). To identify the metals in the particulate matter samples and to determine their abundances, spectroscopic methods were used, specifically inductively coupled plasma mass spectrometry (ICP-MS). Each of these metals may come from a specific source, such as the burning of fossil fuels in fossil fuel power plants; local heating of households; the burning of liquefied fossil fuels in the combustion engines of vehicles; the burning of coal and wood; non-combustion related emissions resulting from vehicular traffic; resuspension of traffic-related dust; and industry. Diesel vehicles and non-combustion emissions from road traffic have been identified as two key sources of the particulate matter. The results reveal that non-combustion emissions, which are associated with the elements Na, Fe, Mn, Ni, Zn, Mo, Sb, Cd, and Pb, are the major contributors, followed by combustion emissions from diesel vehicles, which are associated with the elements Mg, Ca, and Ba.     

长大深埋隧道(连载一)

因工程的复杂性、地质条件的不确定性及施工运营安全的严苛性,长大深埋隧道工程在规划、设计、施工、运营等方面面临诸多技术挑战。文章针对地质勘察、隧道系统方案选择、设计方案、开挖方法和支护系统、施工及运营安全、风险管理等方面提出了具体的建议,可为隧道工程技术人员提供借鉴、指导。     

The simple,compelling case for PRT

When compared with existing urban modes, Personal Rapid Transit (PRT) offers compelling advantages in every important respect. The desirable attributes of any urban mobility mode are well documented, such as minimal travel time, safety, comfort, low cost, and minimal impacts. These attributes are used to define a hypothetical, ideal urban mode. The ideal mode would possess characteristics such as no waiting, no stops, from anywhere to anywhere service, risk-free, non-polluting, and accessible to everyone at any time. Although not attainable in the real world, the ideal provides a model and benchmark for design much as the Carnot thermodynamic cycle guides the development of internal combustion engines, or ideal gases and perfect fluids are postulated in physics. A matrix format is used to present the characteristics of various modes against the desirable attributes of any mode. Modes presented are the ideal, walking, bicycles, motorcycles, automobiles, taxis, buses, rail transit, Automated Guideway Transit (AGT), and PRT. In all respects, PRT is shown to approach the ideal much more closely than competing modes.     

Are we ready to embrace connected and self-driving vehicles? A case study of Texans

While connected, highly automated, and autonomous vehicles (CAVs) will eventually hit the roads, their success and market penetration rates depend largely on public opinions regarding benefits, concerns, and adoption of these technologies. Additionally, the introduction of these technologies is accompanied by uncertainties in their effects on the carsharing market and land use patterns, and raises the need for tolling policies to appease the travel demand induced due to the increased convenience. To these ends, this study surveyed 1088 respondents across Texas to understand their opinions about smart vehicle technologies and related decisions. The key summary statistics indicate that Texans are willing to pay (WTP) $2910, $4607, $7589, and $127 for Level 2, Level 3, and Level 4 automation and connectivity, respectively, on average. Moreover, affordability and equipment failure are Texans’ top two concerns regarding AVs. This study also estimates interval regression and ordered probit models to understand the multivariate correlation between explanatory variables, such as demographics, built-environment attributes, travel patterns, and crash histories, and response variables, including willingness to pay for CAV technologies, adoption rates of shared AVs at different pricing points, home location shift decisions, adoption timing of automation technologies, and opinions about various tolling policies. The practically significant relationships indicate that more experienced licensed drivers and older people associate lower WTP values with all new vehicle technologies. Such parameter estimates help not only in forecasting long-term adoption of CAV technologies, but also help transportation planners in understanding the characteristics of regions with high or low future-year CAV adoption levels, and subsequently, develop smart strategies in respective regions.     

A review of vehicle fuel consumption models to evaluate eco-driving and eco-routing

Fuel consumption models have been widely used to predict fuel consumption and evaluate new vehicle technologies. However, due to the uncertainty and high nonlinearity of fuel systems, it is difficult to develop an accurate fuel consumption model for real-time calculations. Additionally, whether the developed fuel consumption models are suitable for eco-routing and eco-driving systems is unknown. To address these issues, a systematic review of fuel consumption models and the factors that influence fuel economy is presented. First, the primary factors that affect fuel economy, including travel-related, weather-related, vehicle-related, roadway-related, traffic-related, and driver-related factors, are discussed. Then, state-of-the-art fuel consumption models developed after 2000 are summarized and classified into three broad types based on transparency, i.e., white-box, grey-box and black-box models. Consequently, the limitations and potential possibilities of fuel consumption modelling are highlighted in this review.     

德国柏林职业教育模式的启示

文章从德国柏林政府、企业、学校、行会在职业教育中的关系、地位、职责和作用入手,介绍了德国柏林职业教育运行的体制机制情况,并针对我国国情与职业教育现状,提出了加强和改进我国职业教育工作的措施建议。     

基于在线监测的轨道交通网络运营设备维护管理研究

提出对运营设备要注重维护管理,包括设备的前期规划管理、维修模式、管理组织形式、技术管理、信息技术管理、安全管理、备件管理、节能与环保、风险管理、人才培训等方面,简要论述城市轨道交通运营设备综合管理工作的特点,以提高设备维护管理水平。     

海底管道单项高风险因素分析

为了准确掌握海底管道在运行阶段面临的各种单项高风险因素,通过采用相应模型计算和OLGA模拟等方法,以某管道为例,得到了对管道安全影响较大的单项高风险因素为海底管道埋深、海床变化、析蜡可能性、水合物堵塞可能性、结垢、沥青质沉积、抛锚与拖网干扰等、腐蚀、悬跨影响等。文中给出了相应的风险减缓措施,为解决生产实践中海底管道存在的安全隐患提供了依据,预防海底管道事故的发生。     

基于LEAP模型的城市客运交通能耗和污染物排放预测

我国交通运输业能源消耗量与污染物排放量日益增多,交通部门的节能减排措施研究迫在眉睫。本论文基于LEAP模型构建了某城市客运交通能耗与污染物排放模型,并预测了基准情景、政策情景、技术情景及综合情景下该城市客运交通2014-2030年之间的能耗及污染物排放情况。研究表明,三种发展情景下该城市能源需求量及污染物排放较基准情景均有减少,其中综合情景效果最佳,综合情景在2030年的能源消耗与CO2排放可分别减少56.98%和54.55%,CO、HC、NOx与PM2.5可分别减排67.39%、67.27%、51.43%与75.38%。因此应大力发展公共交通,尤其是轨道交通,同时限制私家车的无节制发展,并推广节能环保技术以改善终端利用层次能源结构。     

沿海九省港航发展情况定位分析

通过对沿海辽宁、河北、山东、江苏、浙江、福建、广东、广西和海南等九省2001、2006和2007三年揭示港航发展状态数据的灰色聚类分析,得出了广东的港航发展一直位居第一,浙江已经跃居第二,江苏第三,山东始终排在第四和辽宁正在逐步攀升等重要结论。其结论和揭示的内涵对山东和沿海各省的港航在落实科学发展观、推动现代化发展等方面具有参考价值。     

Panel analysis in transportation planning: An overview

The advantages, disadvantages, and issues involved in the panel analysis of travel behavior are discussed. Increased statistical efficiency, possibility of improved prediction, and the ability to observe changes and examine behavioral dynamics, are among the advantages panel data offer. Their disadvantages, on the other hand, stem from the added biases and costs of panel survey, and increased complexity involved in the analysis. Following a discussion of response lags, leads, and other dynamic elements of travel behavior, the paper offers a brief review of statistical methods available for the analysis of panel data. Use of panel data and dynamic models for demand forecasting is then described, followed by sample size, interview frequency, and other considerations in panel survey design and administration.     

航班快速恢复建模与仿真研究

随着民用航空的发展与竞争,航班延误不仅影响航空飞行的安全与正常,更与航空公司的运营效率、运营成本及乘客利益息息相关。针对某一恶劣天气影响,对某公司受影响航班进行重新调配,考虑到航班的备降、盘旋等待、延误、取消等多种状态,以总成本最小为目标函数,建立航班快速恢复模型,通过MATLAB运用遗传算法设计航班恢复算法进行求解,得出最经济的航班恢复方案。     

A planning methodology for intelligent urban transportation systems

Recent developments in intelligent transportation systems pose new challenges and opportunities for urban transportation planning. To meet these challenges and to exploit these opportunities, a framework for a new transportation planning methodology has been developed. The methodology operates in a computer environment, called PLANiTS (Planning and Analysis Integration for Intelligent Transportation Systems), designed to facilitate the entire planning process form problem identification, through idea generation and analysis, on to prioritization and programming. To assist in problem identification, PLANiTS provides graphic representation of current conditions, including traffic, air pollution, accidents, and projections of future conditions. A computerized knowledge base, containing information about possible strategies and their effects, and a model base, containing transportation and other analysis models, are used to guide the user in identifying potentially effective strategies and performing the appropriate analysis. To facilitate the use of these tools, PLANiTS provides computer support of group processes such as brainstorming, deliberation, and consensus seeking. PLANiTS is designed for use in urban transportation planning at the local, regional, and state levels; it is intended to support a variety of participants in the planning process including transportation professionals, decision makers in transportation agencies (often local elected officials), citizens, and interest groups. Recognizing that transportation planning is essentially a deliberative, political process, PLANiTS is designed to inform and facilitate, but not replace, the political decision-making process.     

隧道粉尘颗粒物的危害及控制措施分析

目前我国隧道大规模快速的发展,而钻爆法以其高效、经济的特点在隧道建设过程中起着至关重要的作用。然而,施工期隧道钻孔、爆破、喷射混凝土、出渣等施工工艺都会扬起大量粉尘颗粒物,严重危害现场人员的身体健康,降低施工现场的能见度影响施工效率和安全,同时大量颗粒物加剧机械设备磨损,在一定程度上影响了设备的使用寿命。结合隧道开挖过程,根据粉尘在隧道内分布规律,粉尘产生因素及运移机理,通过比较隧道减尘、降尘、排尘、除尘、阻尘五种控制措施的特点,提出与现场相适应的粉尘颗粒物综合防治措施,从而减小粉尘的危害,提高现场施工环境质量。     

液化天然气(LNG)汽车日常检查方法及维护技术综述

天然气是一种优质的替代燃料,具有污染小、安全系数高、运行费用低等优点。天然气已经成为城市公共交通领域应用最为成功和广泛的车辆替代燃料技术,为推动交通运输行业的节能减排做出了显著的贡献。液化天然气汽车,作为天然气汽车的一种类型,与传统汽柴油车相比,液化天然气汽车安装了包括液化天然气气瓶、气管路及各种控制阀门和仪表在内的专用装置,在对液化天然气汽车进行日常检查时需要针对液化天然气汽车的专用装置进行重点检查。本文则针对液化天然气汽车的特点,对液化天然气汽车的正确使用方法、日常检查方法及维护技术要求、以及相关注意事项三个方面进行了解读,为指导液化天然气汽车进行日常检查与定期维护提供了技术参考。     

西部地区公路快速客运系统关键技术研究

本篇依托＂西部地区公路快速客运系统关键技术研究＂项目,介绍了公路快速客运的概念、构成要素、服务对象、特征、发展现状及存在的主要问题,指出了公路快速客运系统的车辆、站场、服务、管理、信息等方面的关键技术,形成了公路快速客运系统评价模型,并提出了相应的快速客运发展对策及建议,为我国西部地区的公路快速客运系统建设与发展提供参考依据。     

Well-to-wheel costs,primary energy demand,and greenhouse gas emissions for the production and operation of conventional and alternative vehicles

This study provides a comprehensive comparison of well-to-wheel (WTW) energy demand, WTW GHG emissions, and costs for conventional ICE and alternative passenger car powertrains, including full electric, hybrid, and fuel cell powertrains. Vehicle production, operation, maintenance, and disposal are considered, along with a range of hydrogen production processes, electricity mixes, ICE fuels, and battery types. Results are determined based on a reference vehicle, powertrain efficiencies, life cycle inventory data, and cost estimations. Powertrain performance is measured against a gasoline ICE vehicle. Energy carrier and battery production are found to be the largest contributors to WTW energy demand, GHG emissions, and costs; however, electric powertrain performance is highly sensitive to battery specific energy. ICE and full hybrid vehicles using alternative fuels to gasoline, and fuel cell vehicles using natural gas hydrogen production pathways, are the only powertrains which demonstrate reductions in all three evaluation categories simultaneously (i.e., WTW energy demand, emissions, and costs). Overall, however, WTW emission reductions depend more on the energy carrier production pathway than on the powertrain; hence, alternative energy carriers to gasoline for an ICE-based fleet (including hybrids) should be emphasized from a policy perspective in the short-term. This will ease the transition towards a low-emission fleet in Switzerland.     

The future of transit technology: Lessons from EXPO 86

Expo 86, the World Exposition held last year in Vancouver, Canada, was the largest, special-category world's fair ever staged, with 54 international participants. Given the designated theme of transportation and communications, it is interesting to interpret the statements made by the participants in regard to particular sub-theme areas such as urban transit. This paper reviews the presentations (exhibits, demonstrations, conferences, and seminars) developed by all participants in Expo 86 in regard to urban transit technology, and assesses the significance and direction of technological developments in the areas of vehicle and terminal design, network and system operation and control, and planning and management systems.