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941.
In this paper we describe the shift in membership of the Marine Engineers' Beneficial Association (MEBA), the major us marine engneer labour union, and the problems asssociated with this change. The problematic nature of this change is examined by describing the changing membership of MEBA: demonstrating a relationship between the occupational socialzation of members prior to entering the union and their behaviour as members; and by explaining how the actions of MEBA led to the creation of the problem and the policy it implemented to alleviate the sitution. Data are gathared from participant observation, interviews with union officials and marine engineers. Implications for the formation of sentient groups are discussed. 相似文献
942.
J. Venkatesan G. Nagarajan R. V. Seeniraj R. Murugan 《International Journal of Automotive Technology》2010,11(3):317-322
Mathematical simulation is the process of designing a model of a real system and then conducting experiments with the simulation
to understand the system’s behavior. Mathematical simulation is widely used for investigating and designing compressors, and
with a minimal number of simplifying assumptions, mathematical models can be used in conjunction with modern computing tools
to solve complicated problems. A considerable amount of previous research has focused on the mathematical modeling of reciprocating
air compressors used in automotive braking. The aim of the present work was to experimentally validate the mathematical model
for such compressors. We present a simplified and effective mathematical model for estimating compressor performance, and
this model can easily be executed using personal computers. Parameters such as compressor speed, discharge pressure and clearance
volume were evaluated in terms of their effect on the thermodynamic behavior of compressors. The model can predict cylinder
pressure, cylinder volume, cylinder temperature, valve lift and resultant torque at different crank angles; it can also predict
the free air delivered and the indicated power of the compressor. Therefore, the model has been validated using experimental
results. 相似文献
943.
T. Ciobotaru D. Frunzeti L. Jäntschi 《International Journal of Automotive Technology》2010,11(2):167-172
This paper presents a method for analyzing epicyclic gearboxes by evaluating the speeds, torques and power of the external
elements in epicyclic gear mechanisms, as well as the total ratios of the gear box. The method is based on the equations that
describe each epicyclic gear mechanism and rules that assign appropriate codes to the external elements. The method emphasizes
how power flows are transmitted through the epicyclic gears, as well as power losses. Analysis of an epicyclic gear box is
performed to illustrate the proposed method. 相似文献
944.
Considerations on Rail Corrugation 总被引:4,自引:0,他引:4
945.
通过对广州地铁3号线与北延段信号系统接驳方案的分析,提出该方案在安全可行性、施工步骤和施工方法方面的一些见解,尤其对其硬件实施步骤做了详细分析。 相似文献
946.
通过对计量技术机构的职能分析,结合铁路运输企业的实际情况,阐述计量技术机构如何在铁路跨越式发挥中发挥更大的作用。 相似文献
947.
Alfred J. Baird 《Maritime Policy and Management》2004,31(4):375-391
Seaports are recognized for their importance in facilitating trade growth and associated economic development. These attributes often give rise to the notion that seaports, or infrastructure elements of seaports, are public goods. Public goods are regarded as goods or services which a market acting in isolation might have difficulty in providing, or at least providing in sufficient quantity and/or at a competitive price. An important element of a public good relates to its non-rival consumption, the implication being that it is impossible to exclude anyone, whether they pay or not. Key questions this paper seeks to address are, what constitutes public goods in seaports, to what extent is it necessary for the public sector to provide these goods, and can such intervention lead to market distortion in respect of competing ports? The paper describes the more common examples of public goods in seaports. This is followed by discussion of public and private sector investment at major north European seaports. The paper considers the potential for market distortion due to public sector expenditure on so-called public goods in seaports, and proposes that a more cohesive policy for major ports, particularly those very large containerports serving a common European hinterland, is necessary in order to deliver a sustainable transport system in the long term. 相似文献
948.
949.
950.
M. Hatzopoulou E.J. Miller 《Transportation Research Part D: Transport and Environment》2010,15(6):315-325
This paper describes the development of an integrated approach for assessing ambient air quality and population exposure as a result of road passenger transportation in large urban areas. A microsimulation activity-based travel demand model for the Greater Toronto Area – the Travel Activity Scheduler for Household Agents – is extended with capabilities for modelling and mapping of traffic emissions and atmospheric dispersion. Hourly link-based emissions and zone-based soak emissions were estimated. In addition, hourly roadway emissions were dispersed at a high spatial resolution and the resulting ambient air concentrations were linked with individual time-activity patterns derived from the model to assess person-level daily exposure. The method results in an explicit representation of the temporal and spatial variation in emissions, ambient air quality, and population exposure. 相似文献