A disaggregated land use—transport model for Delhi,India

A Lowry-type land use-transport model stratified both by socio-economic group and urban sub-region is described. The parameters of this model are calibrated from a 1969 urban travel survey conducted in Delhi. Parameter magnitudes are estimated for several versions of the model and the qualities of these calibrations are reported. Applications of the calibrated models to the analysis of alternative development concepts for the Delhi urban region are described.     

Consequences of service reduction in municipal transit: San Francisco’s muni

Urban transit in the United States is going through a crisis of rising costs, increasing fares, falling patronage, and concomitant service reductions; typical of the pattern is San Francisco’s Municipal Railway, the agency in charge of all the City’s transit. From a basic fare of 15c in 1969, two increases brought the fare to 25c by 1972, and cut sharply into a previously stable patronage. The “Muni”, in an effort to reduce costs and meet its budgeted deficit, attempted to reduce service by ten to fifteen percent. From an analysis of the data which could be obtained, it appears that neither efficiency not equity in the City would have been served by the proposed cutbacks. The analysis draws from a variety of sources and methods in exploring the interactions within the transportation system and within the city budget.     

A Note on the Lyapunov Stability Analysis of a Linear Railway Wheelset

In this paper a Lyapunov function is generated for the linearized equations governing a steel wheelset on steel rails. Thus the authors attack the asymmetric problem, and successfully apply Ingwerson's method for constructing Lyapunov functions. The stability criteria applied to this function yield a closed-form expression for the critical forward speed of the wheelset. Thus the authors retain the advantage of Lyapunov's direct method by obtaining an explicit solution for the critical speed. And, although this linearized result has been obtained by other methods, the result is provocative because it suggests that a similar attack on the intractable nonlinear problem (currently being mounted by the authors) may indeed bear fruit.     

The development of ro/ro services in Marseilles: Part 1

This paper discusses the growth of ro-ro services operating to and from Marseilles and the adaption of port structures to facilitate this growth. The concluding section of Part 1 of the paper analyses throughput performance.     

采用异步牵引传动的ЭТ2A型电动车组

电动车组的故障中,40%是发生在牵引电动机和电气设备上.因此应采用更经济、更安全、对旅客和维护人员都更方便的新型电动车组代替已经老化的、使用寿命已到期的直流近郊列车.ЭТ2A型就是新型电动车组之一.文章介绍了其技术参数,分析了其电路原理和技术特点.     

IGBT牵引变流器的发展

简述了IGBT牵引变流器的发展沿革,比较了IGBT与GTO等元件的功率要求和工作特性,分析了IGBT牵引变流器的发展前景,介绍了IGBT牵引变流器的应用实例,得出了在各功率等级的牵引变流器中,IGBT将完全取代GTO晶闸管的结论.     

The Mediterranean Sea, coastal and deep-sea signatures of climatic and environmental changes

At great scales of time and space, the dynamics of the Mediterranean Sea, a concentration basin, are mainly linked to its freshwater budget. This budget is subject to evolutions due to man's use of freshwater and to climatic changes affecting precipitation and/or evaporation. Marine dynamics and Atlantic, atmospheric and terrestrial inputs are strong constraints for the geochemical behaviour of the Mediterranean Sea. From measurements made during the last decades in the deep western water, it appeared that temperature, salinity, nutrients and trace metal concentrations were changing with time. In spite of its depth, the Mediterranean Sea looks like a coastal ocean, according to its coast length, watershed and number of inhabitants and to its fast response to climatic and environmental changes. The changes discovered in deep homogeneous waters are signatures of evolutions occurred in the surface layer. But in this layer and particularly in coastal waters, climatic and/or environmental trends may be masked by seasonal and interannual variabilities of not only physical and chemical characteristics but also climatic forcing or anthropic inputs. Analyses of river runoff, atmospheric inputs or climatic trends together with marine evolutions indicate constraints concerning probable changes in the coastal sea and/or in the surface water and processes involved at the interfaces. Moreover, changes observed in coastal or deep-water constitute new constraints for the modelling of the marine circulation and the transfer of matter.     

Notes on the internationalization process in the maritime sector

In this paper the author traces the evolution of state subsidization of national shipping enterprises, and analyses the processes whereby such enterprises are dependent (to an increasing extent as time passes) on international factors.     

轮缘等离子强化

随着铁路车轮轮缘等离子强化有效性讨论的不断深入，必须仔细研究该强化过程的一些特点和车轮强化后的使用效果。强化工作的问题之一就是要了解车轮轮缘在作强化之前的硬度值是多少。科研人员对此所作的试验表明：为了能使钢轨用钢和轮缘用钢相互间的接触疲劳寿命得到保证，其硬度值应该相似。因此，在讲轮缘强化硬度时必须明白，表面强化工艺会使得强化表面某些区域的局部硬度(显微组织)达到最大值。     

Some aspects of the structural design of a mat foundation for various soil conditions

There are several important structural design parameters in the analysis of a mat type structure for a jackup mobile offshore drilling unit. These consist of dimensions for the mat, soil foundation types, and structural loads. Methods for determining the proper dimension of the mat structure, modeling the structure and its loading cases, modeling the soil conditions and a method for identifying critical load cases for each element and load case is presented. By using a database approach for the finite element output for all of the various loading cases, a rational approach is presented which solves the problem of sorting and analyzing all of the elements and load cases, ensuring that all are included and none of the critical cases are missed.