道路养护成本的分析

介绍了道路养护成本分析的计算方法、成本组成等,并通过实际的方案案例分析,证明养护方案成本对整个道路方案寿命周期成本及方案比选结果的重大影响．     

爱尔兰铁路用2900系新型内燃动车组

介绍了爱尔兰铁路采用的2900系新型内燃动车组的结构特点以及主要设备。     

Optimization of headways with stop‐skipping control: a case study of bus rapid transit system

Bus rapid transit system is designed to provide high‐quality and cost‐efficient passenger transportation services. In order to achieve this design objective, effective scheduling strategies are required. This research aims at improving the operation efficiency and service quality of a BRT system through integrated optimization of its service headways and stop‐skipping strategy. Based on cost analysis for both passengers and operation agencies, an optimization model is established. A genetic algorithms based algorithm and an application‐oriented solution method are developed. Beijing BRT Line 2 has been chosen as a case study, and the effectiveness of the optimal headways with stop‐skipping services under different demand levels has been analyzed. The results has shown that, at a certain demand level, the proposed operating strategy can be most advantageous for passengers with an accepted increase of operating costs, under which the optimum headway is between 3.5 and 5.5 min for stop‐skipping services during the morning peak hour depending on the demand with the provision of stop‐skipping services. The effectiveness of the optimal headways with stop‐skipping services is compared with those of existing headways and optimal headways without stop‐skipping services. The results show that operating strategies under the optimal headways with stop‐skipping services outperforms the other two operating strategies with respect to total costs and in‐vehicle time for passengers. Copyright © 2014 John Wiley & Sons, Ltd.     

沥青路面性能衰减规律的经验法预测模型探讨

沥青路面性能衰减规律的预测模型是进行路面预防性养护管理的重要内容,通过采用经验法预测模型对性能指标IRI、PCI进行分析,来预测路面的使用性能,总结出经验法预测模型的建模程序和使用特点.     

Real-time Monitoring of Subsea Gas Pipelines,Offshore Platforms,and Ship Inspection Scores Using an Automatic Identification System

The aim of this research is to develop an algorithm and application that can perform real-time monitoring of the safety operation of offshore platforms and subsea gas pipelines as well as determine the need for ship inspection using data obtained from automatic identification system (AIS). The research also focuses on the integration of shipping database, AIS data, and others to develop a prototype for designing a real-time monitoring system of offshore platforms and pipelines. A simple concept is used in the development of this prototype, which is achieved by using an overlaying map that outlines the coordinates of the offshore platform and subsea gas pipeline with the ship’s coordinates (longitude/latitude) as detected by AIS. Using such information, we can then build an early warning system (EWS) relayed through short message service (SMS), email, or other means when the ship enters the restricted and exclusion zone of platforms and pipelines. The ship inspection system is developed by combining several attributes. Then, decision analysis software is employed to prioritize the vessel’s four attributes, including ship age, ship type, classification, and flag state. Results show that the EWS can increase the safety level of offshore platforms and pipelines, as well as the efficient use of patrol boats in monitoring the safety of the facilities. Meanwhile, ship inspection enables the port to prioritize the ship to be inspected in accordance with the priority ranking inspection score.     

Particle flux, and composition of sedimenting matter, in the Greenland Sea

Vertical flux of particulate material was recorded with moored sediment traps during 1988/1989 in the Greenland Sea at 72°N, 10°W. This region exhibits pronounced seasonal variability in ice cover. Annual fluxes at 500 m water depth were 22. 79, 8.55, 2.39, 3.81 and 0.51 g m⁻² for total flux (dry weight), carbonate particulate biogenic silicate, particulate organic carbon and nitrogen, respectively. Fluxes increased in April, maximum rates of all compounds occurred in May–June, and consistently high total flux rates of around 100 mg m⁻²d⁻¹ prevailed the summer. The increasing flux of biogenic particles measured in April is indicative of an early onset of algal growth in spring. Small pennate diatoms dominated in the trap collections during April, and were still numerous during the high flux period when Thalassiosira species were the most abundant diatoms. During May–June, up to 22% of the Thalassiosira cells collected were viable-looking cells. The faecal pellet flux increased after the May–June event. Therefore we conclude that the diatoms settled as phytodetritus, most likely in rapidly sinking aggregates. From seasonal nutrient profiles it is concluded that diatoms contribute 25% to new production during spring and 50% on an annual basis. More than 50% of newly produced silicate particles are dissolved above the 500 m horizon. High new production during spring does not lead to a pronounced sedimentation pulse of organic matter during spring but elevated vertical export is observed during the entire growth period.     

影响球铁冲击、拉伸强度的因素

铸造高冲击强度的球铁时,获得持续稳定的结果是非常重要的,尤其是考虑到确保零件在使用末期的使用性能时.例如:在汽车业,必须保证所提供的铸造零件能经得起实际工况,例如寒冷的天气下在坑洼地带其连续冲击的性能.铸造厂最根本的问题是辨别哪里可能存在潜在的断裂源并在铸件"上路"前消除它们.     

DYNAMIC CHANGES IN Giα2 LEVELS IN THE RAT HEART ASSOCIATED WITH IMPAIRED CARDIAC FUNCTION FOLLOWING ACUTE MYOCARDIAL INFA RCT

ＤＹＮＡＭＩＣＣＨＡＮＧＥＳＩＮＧｉα２ＬＥＶＥＬＳＩＮＴＨＥＲＡＴＨＥＡＲＴＡＳＳＯＣＩＡＴＥＤＷＩＴＨＩＭＰＡＩＲＥＤＣＡＲＤＩＡＣＦＵＮＣＴＩＯＮＦＯＬＬＯＷＩＮＧＡＣＵＴＥＭＹＯＣＡＲＤＩＡＬＩＮＦＡＲＣＴＩＯＮＳｋｉＢｉｎｇ；Ｊ．Ｅ．Ｈｅａ...     

铌磷半钢在中磷铸铁闸瓦中应用的研究

本文通过对用铌磷半钢配制的中磷闸瓦的金相组织、力学性能、物理性能和摩擦-磨损特性的研究及其实际运行,证明:其质量指标和使用性能完全满足 TB1159-76标准,并超过普通中磷闸瓦的技术水平;可使中磷铸铁闸瓦的原材料成本降低10%左右.