Information needs of the continuing urban transportation planning process

Urban transportation is identified as a functional element in the broader context of urban facilities and services. From this point of view, the relative merits of separate information systems for transportation planning and general urban planning, as contrasted to unified systems for all urban management functions, are discussed. The overriding need to make the most effective use of urban resources argues strongly for the unification of urban information systems to the greatest possible extent consistent with the special data requirements of various functional programs. The need to identify and correlate data items for very small areal units and to keep current records of the constantly shifting patterns of social and economic activities in urban areas present difficult, but not insurmountable technical problems. However, the most serious barrier to the development and implementation of comprehensive urban information systems is concluded to be institutional, rather than technical, in nature.     

用γ射线料位计监控胶带输送机物料堵塞

在港口胶带输送机系统中,随着输送生产率的提高和胶带运行速度的加快,转接料斗中物料堵塞的现象时常发生.输送过程中,若对堵塞现象不能及时监控并采取有效防范措施,就会导致系统的各种故障,如物料撒落、胶带破损或断裂,甚至有可能造成整个控制系统的误动作,其后果极其严重.目前,尽管很多使用单位在转接料斗处都安装有防堵塞监测装置,但还是经常发生因物料堵塞所造成的各种恶性事故.经分析认为,绝大多数是因其所设置的堵塞监测装置失效造成的.     

Optimal synthesis of function generation in steering linkages

This paper presents an approach to optimize planar mechanisms for function generation synthesis. It is applied to the design of different steering linkages used in road vehicles where the Ackermann condition is formulated as the objective function. Four different mechanisms are kinematically defined and synthesized in terms of the proposed method. Limitations of the size of the elements are also considered by means of inequality constraints. Solutions are presented as the difference between desired behaviour, established by Ackermann, and actual generated performance. The results show that the accuracy achieved by the proposed procedure is satisfactory for working conditions in this type of linkages.     

Modelling journey‐to‐work fuel consumption: a case study of Bayridge subdivision

Fuel consumption is calculated using a modelling procedure for automobiles travelling on three alternative street patterns designed for a subdivision in Kingston Township, Ontario. The modelling procedure is described. The results indicate that grid and solar superblock street patterns, compared to the existing street pattern, offer small fuel savings to a tripmaker in the portion of the work trip travelled in the subdivision.     

舰船EMC数模软件/仿真研究及应用

系统地分析研究了舰船总体电磁兼容性(EMC)数模分析预测软件的建模原理、分析预测功能和工程应用,着重讨论了舰上发射机和非线性结构的"锈蚀螺栓效应"的互调产物等干扰源的数学模型.由于舰船电磁环境的复杂性,预测软件应能够对多参数进行分析.本文详细介绍了该软件的4个模块:天线最佳布置性能分析模块、电缆耦合干扰分析模块、各设备(或分系统)间电磁兼容性分析模块、大功率设备辐射近场场强分布分析模块.工程实践证明,该软件预测精度满足要求.     

道路交通事故紧急救援保障体系与技术支持

我国汽车保有量仅占全球汽车保有量的3%,而每年死于交通事故的人数约占全球死于交通事故人数的15%20%,尤其交通事故致死率是日本等国家的1020倍。本文就此现象进行基本原因的分析,并着重对交通事故紧急救援保障体系与技术支持问题进行探讨。     

Protecting Rhode Island's coastal salt ponds: An economic assessment of downzoning

Abstract

In southern Rhode Island, there is growing concern that housing and recreational demands will soon overwhelm the capacity of the coastal salt ponds to absorb wastes, produce seafood, and maintain scenic qualities. As a result, coastal towns have been studying the feasibility of using land controls such as downzoning to protect these coastal amenities. The paper presents an economic analysis of the downzoning program proposed in the town of South Kingstown. Hedonic price and contingent valuation methods are used to value coastal amenities. The estimated net present value of “swimmable” water is shown to be $3.1 million.     

RP2000抗车辙沥青混合料在朔州的应用研究

通过RP2000沥青混合料的试验可知,RP2000可显著提高沥青混合料的高温抗车辙性能,同时改善低温抗变形能力。综合高低温性能,RP2000的最佳掺加量为沥青混合料的4‰～6‰。