Flange Force Effects on the Motion of a Train Wheelset

The motion of a train wheelset is investigated using Hopf bifurcation theory. The method takes full account of the nonlinear effects of the flange-rail contact forces which are incorporated in the model; The numerical solution is obtained over a wide range of forward speeds by transforming the bifurcation problem into a regular nonlinear boundary value problem, which is solved by standard methods. This solution is shown to be orbitally, asymptotically stable. The algorithm supplies complete information on the lateral and yaw motions and on the period of oscillation, even for very high forward speeds.     

A Method to Analyse the Dynamic Behavior of a Motorcycle Front Suspension Equipped with Sequential Dampers

This work analyses the dynamic behavior of a motorcycle front suspension equipped with passive sequential hydraulic dampers, in some operative situations. The dampers, with non-linear and asymmetric characteristics, may be regulated in six different ways. Using experimental elasticity and damping data as reference parameters, and a simplified two-degrees-of-freedom model, some dynamic simulations were carried out in order to define damping parameters for optimal comfort and safety.     

Steel product flows: works-to-port: an application of the 'transportation problem'

The pattern of landward flows of steel products between manufacturing works and ports in the United Kingdom used for export is examined, and the spatial implications of various levels of hypothetical rationalization in the distribution of port facilities discussed. While extreme spatial concentration of port facilities for handling general steels would seem both impracticable and undesirable, the analysis suggests that a greater degree of rationalization than at present could be achieved without increasing overall landward transport costs.     

Establishing value of time for the inter-island passenger transport of the Western Visayas region,Philippines

Transportation infrastructure planning process requires cost–benefit analysis in the evaluation of project proposals. Value of time (VOT) facilitates the conversion of travel time savings, which is a significant proportion of benefits in monetary terms. In cases where VOT has not been established, planners resort to crude estimates that often results in erroneous or biased measurements of benefits. This is the case of the Western Visayas region in the Philippines where transportation studies are rare. Secondary cities and its peripheral regions have often been overlooked subjects of transportation studies. In this study, multinomial logit models using revealed preference data were estimated to facilitate the calculation of the VOT. The total cost, square of the total cost, and total time were identified as significant explanatory variables affecting mode choice. The square of the total cost term was introduced in the models in order to account for income effect. Results indicate that VOT estimates for the inter-island passenger transportation between Iloilo and Negros Occidental generally range from 78.15PHP to 179.15PHP (1.91USD to 4.37USD) depending on trip and traveller characteristics.     

EXPRESSION CLONING OF A PROTECTIVE LEISHMANIA ANTIGEN

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REGULATION OF THE INTERFERON－INDUCIBLE PROTEIN KINASEPKR AND2＇5＇ OLIGOADENYLATE SYNTHETASE BY A CATALYTICALLY INACTIVE PKR M

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视觉维生素

当知道兰博基尼现在推出Gallardo的双色特别版本时,我问自己:那有多出奇、多吸引眼球呢?应该只比你在沙漠找到一堆黄沙,抑或在动物园邂运一头大象多一点点惊喜吧?这特别版车款提供Giallo Midas、ArancioBorealis、Grigio Telesto、Bianco Monocerus及Blu     

12毫米厚铝合金板的搅拌摩擦焊研究(英文)

Most of the investigations regarding friction stir welding(FSW)of aluminum alloy plates have been limited to about 5 to 6mm thick plates.In prior work conducted the various aspects concerning the process parameters and the FSW tool geometry were studied utilizing friction stir welding of 12 mm thick commercial grade aluminum alloy.Two different simple-tomanufacture tool geometries were used.The effect of varying welding parameters and dwell time of FSW tool on mechanical properties and weld quality was examined.It was observed that in order to achieve a defect free welding on such thick aluminum alloy plates,tool having trapezoidal pin geometry was suitable.Adequate tensile strength and ductility can be achieved utilizing a combination of high tool rotational speed of about 2000 r/min and low speed of welding around 28 mm/min.At very low and high dwell time the ductility of welded joints are reduced significantly.     

Operating differential subsidies: problems and alternatives for the United States

In this paper a proposal for a Competitive Rate of Return (CRR) based operating-subsidy system is made as an alternative to the existing US foreign-cost parity ODS system. Such an alternative, if adopted, could be successful in meaningfully relating US government maritime subsidy programmes to the legitimate financial needs of the industry. From the operator's viewpoint, the risk of drastic revenue fluctuations is removed, yet adequate opportunities are provided for firms with above average performance to be rewarded for their efficiency in higher than average profits. similarly, poorly run firms have an opportunity to lose money, in spite of government subsidies.

From the government's viewpoint, the CRR programme guarantees the provision of essential shipping services at the lowest possible cost. Because of substantial incentives to the operator on both the revenue and cost side of his profit equation, it is more likely that long-run government operating subsidies can be reduced under CRR than under the present system.

Although the CRR system has been described for use in determining subsidies for both bulk and general cargo carriers, it has been recommended that this system be considered first for implementation in the case of bulk vessels, because of the newness of the bulk subsidy programme. In addition, the 1970 Act gives MarAd the flexibility to initiate such a programme for bulk vessels without the necessity of new legislation.