Strategies of state and local government in management of urban transport problems – A case of Delhi

In India, different layers of Government control different policy instruments to tackle transport externalities which might result in coordination problems and possible efficiency losses. This paper, therefore, addresses the coordination problem resulting from the division of policy instruments between two different government levels that face different types of externalities in varying degrees of magnitude in the urban transport sector by developing three types of theoretical models: the Full Control Centralised Model where the state government has full control over all pricing instrument; a Nash equilibrium model where each of the government levels controls only one instrument and takes the behaviour of the other as given; and a Stackelberg equilibrium mode where the behaviour of the state government is influenced by the fact that one of the price instruments is controlled by the local government. With an empirical illustration of the model for Delhi, the paper finds that since there are many interactions and many externalities between the two levels of government, a division of roles between them does not guarantee an efficient pricing outcome and the efficiency of pricing would depend on the institutional set up and on the correspondence between the objective functions of the two government levels.     

斗轮堆取料机行走电机的变频器调速设计

斗轮堆取料机是大型散货港口连续装卸系统的核心工具。本文介绍了斗轮机行走电机的变频器调速方法,降低了维护量,拥有较强的故障诊断功能,能够提高系统的可靠性,同时也可以降低生产经济成本。     

ABB ACS800 变频器常见故障及处理

ABB变频器ACS800变频器结构复杂,出现故障后的维修周期长,会造成设备长时间停车。本文通过总结近些年维修变频器的经验,分析变频器常见的故障及维修思路,从而保障了设备的正常运行。     

WC5R煤矿用防爆柴油机无轨胶轮指挥车设计

为积极响应国家政策,保障煤矿高产高效、安全生产,设计开发了WC5R煤矿用防爆柴油机无轨胶轮指挥车,介绍了其设计原理及总体结构。     

Remaining fatigue life assessment of corroded mooring chains using crack growth modelling

Failures caused by the combined actions of fatigue, corrosion and wear are important safety concerns for mooring chains used on floating structures in the oil and gas industry. Prediction of remaining corrosion fatigue life based on surface condition could therefore be a useful tool for the continued safe operation of corroded chains. This paper investigates the use of crack growth modelling for estimating the remaining corrosion fatigue life of mooring chains that exhibit significant pitting corrosion damage. A crack growth modelling approach is used to produce remaining fatigue life estimates for a selection of severely pitted mooring chains. Using fatigue crack growth rate test results for grade R4 high strength mooring chain steel, empirical crack growth laws are presented for free corrosion and cathodic protection conditions at load ratio R = 0.1. Two different methods for establishing equivalent cracks from surface scans of corrosion damage are presented. The mooring chains are proof loaded as part of their manufacturing process. Residual stresses introduced during this process have therefore been determined by finite element analysis and accounted for in the fatigue crack growth predictions. One of the equivalent crack models, accounting for the single dominant corrosion pit, provided quite accurate fatigue life predictions when compared with full scale test results.