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441.
442.
铁建设号 《铁路工程造价管理》2011,26(1):57-57
铁建设[2010]223号2010年11月20日各铁路局,各铁路公司(筹备组),投资、集装箱公司:现公布《铁路路基工程预算定额》、《铁路桥涵工程预算定额》、《铁路隧道工程预算定额》、 相似文献
443.
444.
Torque characteristics analysis for optimal design of a copper-layered eddy current brake system 总被引:1,自引:0,他引:1
An enhanced parametric model for a copper-layered eddy current electric machine (retarder) is introduced in this paper. The
modeled torque characteristics of the copper-layered electromagnetic retarders are based on the results from a detailed electromagnetic
finite element analysis (FEA) of these eddy current machines. The model uses a parameterized double-exponential function to
model the steady state speed-torque characteristics of the retarder. The parameters are adjusted for optimal braking performance
in conjunction with predicted speed-torque characteristics of a copper-layered retarder. A full vehicle model, along with
the proposed retarder speed-torque model has been used to simulate a series braking events. The simulation results show that
the peaks of the retarder speed-torque curves must be designed to occur within a specific range of speeds for optimal braking
performance. 相似文献
445.
446.
Sheldon H. Jacobson Douglas M. King 《Transportation Research Part D: Transport and Environment》2009,14(1):6-13
High rates of oil consumption and obesity in the US have become important socioeconomic concerns. While these concerns may seem unrelated at first, growing obesity rates in the US increase fuel consumption by adding passenger weight to vehicles. This paper estimates the additional amount of fuel (i.e., gasoline) consumed annually by noncommercial passenger highway vehicles in the US due to passenger overweight and obesity. The mathematical model presented in this paper estimates that as many as one billion additional gallons of gasoline are consumed each year due to overweight and obesity in the US, accounting for up to 0.8% of the fuel consumed by these vehicles annually. This additional fuel consumption causes carbon dioxide emissions of up to 20 billion pounds or more, accounting for up to 0.5% of the annual carbon dioxide emissions in the transportation sector. 相似文献
447.
FlexRay is a reliable and hard real-time in-vehicle communication protocol that is strongly promoted by car manufacturers as the de facto standard in the automotive domain. The protocol offers both a time-triggered and an eventtriggered architecture. This paper focuses on the optimal scheduling of the time-triggered component of FlexRay known as the static (ST) segment using a two-dimensional bin-packing technique. To maximize the bandwidth utilization in the ST segment, a fast heuristic as well as an efficient integer linear programming approach are proposed. Our methods directly schedule signals into slots including frame packing, according to signal-based data scheduling and the slot/ cycle multiplexing mechanisms presented by the latest version of the FlexRay protocol. The benefits of our proposed methods are demonstrated by extensive experiments on synthetic and an automotive X-by-wire system case study. An additional test case is examined to emphasize the superior performance of the proposed approach relative to that of existing optimal scheduling approaches. 相似文献
448.
449.
Experimental research results of surface damage accumulation in rail steel under rolling with slippage are presented. Hertz contact for two rollers made of rail and wheel steels was realized in the test. The influence of loading regime upon wear of rail is considered. The estimation of characteristics of surface fracture resistance for rail steel is made. The method to predict the life of rail steel under given conditions of regular loading is proposed. 相似文献
450.
I. C. Millar 《Maritime Policy and Management》2013,40(1):9-15
The paper questions why so little attention has been given to the primary control centre of a merchant ship, namely the bridge, when so many accidents at sea are caused by ‘human error’. The paper then suggests that there is a need for a policy which will draw the various threads of the problem together in a form suitable for international discussion and even legislation. The identified areas are those of training, bridge design, psychology and marine traffic discipline. 相似文献