A research agenda for increasing safety belt use in the United States

On November 13-14, 2003, a symposium on high-visibility safety belt use enforcement in Raleigh, NC: (a) celebrated the 10th anniversary of North Carolina's Click It or Ticket program; (b) documented current knowledge regarding safety belt use; (c) proposed strategies to increase use further; and (d) discussed research to support these strategies.     

Study on convection and dispersion characteristics of dense gases in urban environment considering trees

Although several studies on the dispersion of heavy toxic gas released from ruptured tanks on vehicles during transportation have considered complex terrain such as urban buildings, the influence of trees on the flow field in urban areas during gas dispersion tends to be ignored. In this study, a Computational Fluid Dynamics (CFD) model was proposed to investigate the characteristics of gas release and dispersion from loaded vehicle in the urban environment. In this model, the tree crown was treated as a porous medium, and the influence of drag due to the crown was incorporated into the model by a momentum source term through a user-defined function. In this study, the dynamic characteristics of chlorine (Cl₂) dispersion under the conditions of building distribution, tree species and porosities were comprehensively analysed, to cover the influence of urban complexity, leaf density, and tree planting configuration. The results show that compared with flat terrain, the presence of urban buildings will prolong the dense gas retention time and increase the dangerous distance. It is found that the horizontal dispersion distance can increase by 63% and the isosurface of 25 ppm hazardous gas can increase by 130% with the introduction of buildings. Compared with the terrain with only buildings, the introduction of arbors or shrubs can result in a 147% or 359% increase in the maximum concentration. Also, trees will prolong the dispersion duration. It is also found that the higher the porosity, the less the wind blocking effect, and the weaker the ability of capturing gas. The wind field affected by arbores and shrubs are different in height, and arbores capture more Cl₂. Planting short shrubs around buildings can effectively reduce the spread of harmful gases.     

简易升降类机械式停车设备安全隐患探析

随着人们生活水平的提高,单个家庭购买多部汽车的情况在逐年增加,停车位一位难求的矛盾比较突出。住宅小区家庭用户购买的单个平面停车位向立体2个停车位拓展情况成为趋势。本文从防载车板坠落装置设置、同步检测装置、载车板升降过程中视线盲区三个方面分析其安全隐患,并有针对性地提出一些建议,旨在减少简易升降类机械式停车设备的安全隐患提供有益帮助。     

Reducing emissions from in-use vehicles: an evaluation of the Phoenix inspection and maintenance program using test results and independent emissions measurements

Various federal regulations require states to evaluate the effectiveness of their vehicle inspection and maintenance (I/M) programs in reducing in-use emissions. One method to evaluate program effectiveness is to compare initial and final program test results of individual vehicles. Unscheduled emissions measurements, from remote sensing measurement or roadside pullover testing, can also be used to provide an independent assessment of program effectiveness. We compared emissions reductions from the Arizona IM240 program measured by program data and a large set of remote sensing measurements. Remote sensing measurements indicate smaller emission reductions from the program than those calculated directly from program test results. We discuss some possible causes of the differences obtained from the two sets of measurements.     

不同类型机动车尾气中芳香烃化合物含量分析

首次对北京市9种车辆、5种燃料在不同工况下排放芳香烃化合物的特征．进行了定量研究。结果表明,车型、燃料、净化器及工况等因素对排放量产生影响,电喷车比化油器车芳香烃化合物排放量低;汽油车排放量最高,柴油车其次,LPG及CNG车排放量最低;使用净化器可以降低芳香烃排放量;不同工况对排放量的影响随车型,燃料类型的不同而不同。     

机动车尾气排放检测方法对比分析

通过怠速、双怠速法对机动车尾气检测试验和数据对比分析表明,不同车龄段的电喷型轿车采用怠速法检测尾气达标率在73.3%～93.5%之间;双怠速法检测尾气达标率在40.0%～82.6%之间.不同车龄段的化油器型轿车采用怠速法检测尾气达标率在25.0%～57.1%之间;双怠速法检测尾气达标率在18.8%～57.1%之间.指出双怠速法对化油器车辆尾气控制同样有效果,双怠速法对筛选高污染车辆比怠速法更严格和科学.     

美国资产证券化中的政府作用对我国的借鉴

美国政府在资产证券化创设过程中发挥了巨大的作用。为推动我国资产证券化的开展，我国政府可借鉴美国做法，采取修订法律、营造金融环境、设置政府机构等措施。     

福州市机动车污染及其控制对策

通过对福州市城区道路的车流量及车辆构成状况的调查，估算城市中心区域机动车排气CO、THC和NO2的污染物排放量，分析不同车型的机动车排气污染和贡献率，提出对机动车排气污染的控制对策措施。     

车轮通用打字模设计

根据本单位生产设备特点及车轮的工艺要求，进行工艺分析，设计实用、可靠、灵活、操作简便的通用打字模。     

Buses retrofitting with diesel particle filters: Real-world fuel economy and roadworthiness test considerations

Retrofitting older vehicles with diesel particulate filter(DPF) is a cost-effective measure to quickly and efficiently reduce particulate matter emissions. This study experimentally analyzes real-world performance of buses retrofitted with CRT DPFs. 18 in-use Euro III technology urban and intercity buses were investigated for a period of 12 months. The influence of the DPF and of the vehicle natural aging on buses fuel economy are analyzed and discussed. While the effect of natural deterioration is about 1.2%–1.3%, DPF contribution to fuel economy penalty is found to be 0.6% to 1.8%, depending on the bus type. DPF filtration efficiency is analyzed throughout the study and found to be in average 96% in the size range of 23–560 nm. Four different load and non-load engine operating modes are investigated on their appropriateness for roadworthiness tests. High idle is found to be the most suitable regime for PN diagnostics considering particle number filtration efficiency.