首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6篇
  免费   0篇
公路运输   2篇
水路运输   3篇
综合运输   1篇
  2018年   1篇
  2013年   4篇
  2001年   1篇
排序方式: 共有6条查询结果,搜索用时 31 毫秒
1
1.
According to the terms of the Ministerial Declaration on the Protection of the North Sea, input of the nutrients phosphorus (P) and nitrogen (N) to the coast from the Norwegian‐Swedish border to Lindesnes should be reduced by about 50% between 1985 and 1995. The State Pollution Control Authority (SFT) has analyzed how Norway can achieve this reduction in the most cost‐effective way and at the same time achieve the greatest possible improvement in water quality along the Norwegian coast and in its watercourses.

Two alternative sets of measures were analyzed, both of which would meet the requirements of the Declaration. The lowest‐cost alternative would have average annual costs of about NKr 930 million (U.S.S150 million), and investments of about NKr 4000 million (U.S. $643 million). However, this set of measures would not take account of local water quality, and measures would therefore not always be introduced where the need is most pressing. SFT proposed that an alternative set of measures be implemented, almost all of which would also help to achieve local goals for water quality. This alternative will have annual costs of about NKr 980 million (U.S.$158 million), and investments of about NKr 4100 million (U.S.$659 million).  相似文献   
2.
In this article a theoretical investigation of the dynamics of a railway bogie running on a tangent track with a periodic disturbance of the lateral track geometry is presented. The dynamics is computed for two values of the speed of the vehicle in combination with different values of the wavelength and amplitude of the disturbance. Depending on the combinations of the speed, the wavelength and the amplitude, straight line forward motion, different modes of symmetric or asymmetric periodic oscillations or aperiodic motions, which are presumably chaotic, are found. Statistical methods are applied for the investigation. In the case of sinusoidal oscillations they provide information about the phase shift between the different variables and the amplitudes of the oscillations. In the case of an aperiodic motion the statistical measures indicate some non-smooth transitions.  相似文献   
3.
The Finnish maritime cluster is an important sector of Finland's economy. However, literature on innovative activities within the cluster is limited. This article focuses on Finnish shipbuilding and marine industry firms. Several innovation types are identified. These are analyzed according to general characteristics of firms. The data is from a survey of 148 shipbuilding and marine industry companies; most of the variables are ordinal scale and are analyzed with standard statistical survey methods. Considering the significance and past technological achievements of the sector the results indicate surprisingly low radical innovation related-activity and attitudes towards it. As well, the results provide no evidence to support previous research, suggesting that the shipbuilding and marine industry produces more organizational than technological innovations. The innovativeness of the firms varies according to distinct characteristics such as size, intensity of in-house and collaborative R&D activities, and level of internationalization. The empirical results provide a platform for policy implications and directions for future research; innovations concerning environmental efficiency are raised as an important future area of development.  相似文献   
4.
A unified engine torque actuator for heavy-duty vehicles is developed in this paper. Based on averaging and identification of the instantaneous torque response for changes in brake valve timing and fuel flow, we derive a control oriented engine model of a six cylinder, 350 Hp turbocharged diesel engine, equipped with a compression brake. This work bridges the gap between the detailed compression crank angle based models developed in the engine design community, and the first order lag representation of diesel engine torque response used in the vehicle dynamics community. Moreover, we integrate the compression brake actuator with the service brakes and design a PI-controller that emulates the driver's actions during long descends on grades. The controller simply uses the engine speed measurement to activate the service brakes only when needed.  相似文献   
5.
We modeled the projections of the major atmospheric emissions from shipping of the European sulphur emission control area that includes the Baltic Sea, the North Sea, and the English Channel until 2040. Emission projections were calculated separately for every ship on annual basis, and the model took into account traffic growth, fleet renewal, and the forthcoming regulations. The regulation on sulfur content of ship fuels will drastically decrease the emissions of sulfur oxides and particulate matter (PM2.5). As the regulation on nitrogen oxides (NO x ) only affects the new diesel engines, the decrease in emissions will be seen parallel with the fleet renewal. Globally internalized limits will turn NO x emissions to decrease with moderate traffic growth. However, by designating the Baltic Sea and the North Sea as NO x emission control areas, more drastic decrease would occur. CO2 emissions will stay almost constant through the studied timeline. Results show that European Commission's CO2 target for 2050 will not be reached without implementation of market based measures among the North Sea and the Baltic Sea fleets. Results present new information for decision makers to further develop international regulations of shipping especially in the Baltic Sea and the North Sea.  相似文献   
6.
Global climate change will affect road networks during this century. The effects will be different in various parts of the world due to differences in local climate change and in the structure and properties of roads. In this paper, climate change projections are presented for climate variables that are most likely to affect the long-term performance of road networks in Europe. We apply four regional climate simulations up to the year 2100 using two plausible future emission scenarios. The results show that the changing climate will require significant adaptation measures in the near future in order to maintain the operability of the European road network.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号