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991.
Gotthard Gauci 《WMU Journal of Maritime Affairs》2012,11(1):115-128
Whereas the Marine Insurance Act 1906 provides substantial detail about total losses, very little is provided in relation
to piracy in the said statute. The recent judgments in Masefield v Amlin by Steel J ([2010] 1Lloyd's Rep. IR 345) and then by the English Court of Appeal ([2011] EWCA Civ 24) have highlighted the
difficulties associated with determining whether a seizure of the subject-matter of insurance, in this case cargo, by pirates,
demanding a ransom, can give rise to a claim for a total loss. This is a very important matter which also raises issues of
legality and public policy. This article examines the implications of this judgment against the backdrop of the English marine
insurance definition of piracy and the intricacies of the law relating to constructive and actual total losses. The article
concludes with the suggestion that possibly the marine insurance definition of piracy should tally with that in the domain
of public international law, and further, that legislative intervention should be considered for the purpose of ascertaining
the point in time whether and when seizure by pirates can constitute a total loss. 相似文献
992.
Hans Liwång 《WMU Journal of Maritime Affairs》2017,16(3):385-403
Piracy is one of the most frequent maritime threats. However, despite the importance of how maritime piracy is to be reduced, it is substantially less investigated than maritime safety. Piracy off Somalia is the most investigated case of piracy, but those results are not necessarily generalizable. Piracy off West Africa has been shown to be more diverse, successful and dangerous. This study investigates and analyses piracy off West Africa with the aim to understand how different operations and security measures affect the consequences of piracy. This study has identified several different intents and shows that most attacks are relatively close to shore and correspond to areas of high ship density. Attacks with the intent of theft at night-time are generally performed close to shore, and more complicated attacks against ships under way are more common during daytime and farther from shore. Five types of measures are found to have high effectiveness if the attack is detected during approach; after boarding, only two measures have high effectiveness. Of the effective measures, it can be concluded that all but one are dependent on detecting the attack. Therefore, detecting the pirates is key but must be accompanied by a set of measures because no measure alone can protect a ship given the operational conditions off West Africa. The risks associated with piracy off West Africa are estimated to be of the same magnitude as the risks posed by Somali piracy at its peak. 相似文献
993.
Robust public transport networks are important, since disruptions decrease the public transport accessibility of areas. Despite this importance, the full passenger impacts of public transport network vulnerability have not yet been considered in science and practice. We have developed a methodology to identify the most vulnerable links in the total, multi-level public transport network and to quantify the societal costs of link vulnerability for these identified links. Contrary to traditional single-level network approaches, we consider the integrated, total multi-level PT network in the identification and quantification of link vulnerability, including PT services on other network levels which remain available once a disturbance occurs. We also incorporate both exposure to large, non-recurrent disturbances and the impacts of these disturbances explicitly when identifying and quantifying link vulnerability. This results in complete and realistic insights into the negative accessibility impacts of disturbances. Our methodology is applied to a case study in the Netherlands, using a dataset containing 2.5 years of disturbance information. Our results show that especially crowded links of the light rail/metro network are vulnerable, due to the combination of relatively high disruption exposure and relatively high passenger flows. The proposed methodology allows quantification of robustness benefits of measures, in addition to the costs of these measures. Showing the value of robustness, our work can support and rationalize the decision-making process of public transport operators and authorities regarding the implementation of robustness measures. 相似文献
994.
The deep understanding on sand and sand dunes scale can be useful to reveal the formation mechanism of the sandstorm for early sandstorm forecast. The current sandstorm observation methods are mainly based on conventional meteorological station and satellites remote sensing, which are difficult to acquire sand scale information. A wireless sensing network is implemented in the hinterland of desert, which includes ad hoc network, sensor, global positioning system (GPS) and system integration technology. The wireless network is a three-layer architecture and daisy chain topology network, which consists of control station, master robots and slave robots. Every three robots including one master robot and its two slave robots forms an ad hoc network. Master robots directly communicate with radio base station. Information will be sent to remote information center. Data sensing system including different kinds of sensors and desert robots is developed. A desert robot is designed and implemented as unmanned probing movable nodes and sensors’ carrier. A new optical fiber sensor is exploited to measure vibration of sand in particular. The whole system, which is delivered to the testing field in hinterland of desert (25 km far from base station), has been proved efficient for data acquisition. 相似文献
995.
热管--一种高效实用的散热方法 总被引:1,自引:0,他引:1
任何电子器件冷却的热电路都是由3个最基本的热阻组成的:结-壳热阻Rj-c;壳-散热器热阻Rc-s和散热器至周围介质的热阻Rs-a.为降低这些热阻的临界值,许多工程师费尽心血.文章讨论采用热管有助于降低热阻Rs-a至最小值.散热器至周围介质的热阻是由传导、对流/辐射和被加热的冷却介质形成的3个热阻组成的.典型的风冷散热器中,空气温升的热阻是通风量的直接函数,对流热阻是散热表面积的函数,传导热阻是散热器材料的热导率和几何尺寸的函数.热管能把传导损耗降至最小值,它允许加大散热表面,而且使给定风速下的流量最大,从而有效降低散热器的3个主热阻.文章讨论了能降低风冷散热器热阻的热管. 相似文献
996.
R.S. Sharp D.A. Wilson 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1990,19(6):353-363
Input correlations involving time delays are common in active vehicle suspension system problems. One approach to control law derivation fur such systems is to restrict attention to slate feedback laws in the interests of practicality and it is then of interest to determine the law which is, in some sense, the best. Under assumptions which are common in this area. relating to input, system and cost Function forms, a new derivation of the expression for the cost, accounting for time delays, is given. The use of the expression in numerical procedures for determining effective control gains is discussed and an example for a half car planar vehicle model is described. By comparing results with existing ones which are truly optimal, an estimate is made of the loss of performance which results from the restriction of the control law form in this case. Some generalisation of the results is attempted and they are placed in a contemporary context at the conclusion. 相似文献
997.
998.
Many porting systems for internal combustion engines have been tried and tested over the years, however the basic spring actuated
poppet valve system has prevailed over the last century. In the goal to lower engine output parasitic losses, a simple rotary
valve porting system design is proposed and analyzed. The proposed design concept takes into consideration and combines all
the prominent advantages of many ealier mutlitiple design variations over the past century. The inherent primary advantage
of such a rotary porting system is the elimination of reciprocating components, thus lowering vibration, and removal of highly
stiff springs which contribute to considerable system power loss. Comparable sized 3-D representations of both systems are
constructed in CAD (Computer Aided Design) software in order to run mechanical and fluid simulations to validate the efficiency
advantage of a rotary valve porting system. Using Pro/Engineer Mechanism Dynamics module, the minimum torque required to actuate
both systems at 2000 rpm and 3000 rpm is determined. Fluid simulations are performed using a commercial software CFDesign
V10. Volumetric flow rates are compared during the intake stroke as well as turbulence intensity factors which characterizes
a systems ability to properly mix the Air/Fuel mixture and the combustion efficiency. Some possible improvement on the rotary
geometry is suggested. 相似文献
999.
The hybridization of the conventional thermal vehicles nowadays constitutes a paramount importance for car manufacturers,
facing the challenge of minimizing the consumption of the road transport. Although hybrid power train technologies did not
converge towards a single solution, series/parallel power trains with power-split electromechanical transmissions prove to
be the most promising hybrid technology. In fact, these power trains show maximum power train overall efficiency and maximum
fuel reduction in almost all driving conditions compared to the conventional and other hybrid power trains. This paper addresses
the model and design of the electro-mechanical configuration of one of the most effective HEV power trains: case study of
the 2nd generation Prius. It presents the simulation work of the overall operation of the Toyota Hybrid System (THS-II) of
the Prius, and explores not only its power-split eCVT innovative transmission system but also its overall supervision controller
for energy management. The kinematic and dynamic behaviors of the THS-II power train are explained based on the power-split
aspect of its transmission through a planetary gear train. Then, the possible regular driving functionalities that result
from its eCVT operation and the energy flow within its power train are outlined. A feed-forward dynamic model of the studied
power train is next proposed, supervised by a rule-based engineering intuition controller. The energy consumption of the THS-II
proposed model has been validated by comparing simulation results to published results on European, American and Japanese
regulatory driving cycles. 相似文献
1000.
Aircraft Landing Gear Dynamics: Simulation and Control 总被引:2,自引:0,他引:2
W. Krü ger I. Besselink D. Cowling D.B. Doan W. Kortü m W. Krabacher 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1997,28(2):119-158
The landing gear is an inevitable system for the aircraft. It absorbs the energy of the landing impact and carries the aircraft weight at all ground operations, including take off, taxiing, and towing. Numerical simulation has become an invaluable tool for the assessment of landing gear dynamics as well as of aircraft/landing gear interaction. This paper gives an overview of the landing gear requirements and illustrates landing gear operational conditions, i.e., the shimmy problem, the dynamics at touch down and at ground roll. Furthermore, three software packages used in the simulation of aircraft ground dynamics are presented. A look at flight simulators and landing gear test facilities follows. Finally, the possible application of controlled landing gears is discussed. 相似文献