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1.
文中以一起典型的VTS覆盖水域船舶碰撞危险事件为例,论述了碰撞危险局面下VTS值班员交通组织的依据、措施建议和值班用语规范,为规范VTS值班员的交通组织标准提供思路。 相似文献
2.
本文依托长江南槽一期深水航道整治工程,在深入研究现有块石水下抛填方法的基础上,研发了新型的开敞式深水快速高精度抛填和整平一体化新设备,对其可行性进行了多次测试试验,确定了装备的选型。并采用数值模拟、物模试验等结合的方法进行了结构的验算,确保设备的使用可靠性。该设备可以适应35m水深、2m/s流速,配有实时定位系统,可以实时采集抛填区域的施工效果,实现了抛填和夯平施工和质量检测一体化,通过施工数据分析,该设备达到了93%的抛填合格率,在精度提高至±20cm时合格率可达85%,整平精度可以达到5cm,创新了抛填施工的新装备,经鉴定,该装备达到了国际先进水平,可为类似设备建造选型提供借鉴。 相似文献
3.
Ing-Marie Gren Andreas Brutemark Annika K. Jägerbrand Jennie Barthel Svedén 《运输评论》2020,40(4):411-428
ABSTRACTThis study estimated the external cost of air pollution from shipping by means of a meta-regression analysis, which has not been made before. Three pollutants, which were included in most of the primary studies, were considered: nitrogen oxides (NOx), sulphur dioxides (SO2) and particulate matters with a diameter of max 2.5 micrometres (PM2.5). All primary studies included damages of health and a majority added impacts on agriculture and estimated the cost of air pollutants by transferring cost estimates from studies on costs of air emissions from transports in Europe. Different regression models and estimators were used and robust results were found of statistically significant emission elasticities of below one, i.e. total external costs increase by less than 1% when emissions increase by 1%. There was a small variation between the pollutants, with the highest elasticity for PM2.5 and lowest for NOx. Calculations of the marginal external cost of the pollutants showed the same pattern, with this cost being approximately six times higher for PM2.5 than for the other pollutants. Common to all pollutants was that the marginal external cost decreases when emission increases. Another robust result was a significant increase in the cost of studies published in journals compared with other publication outlets. These findings point out some caution when transferring constant external unit cost of air pollutant from shipping, which is much applied in the literature, and the cost functions estimated in this study could thus provide a complementary transfer mechanism. 相似文献
4.
ABSTRACTDue to the constant risk of piracy and terrorist attacks which cause disturbances within international shipping of goods, barriers to the adoption of maritime security guidelines (MSGs) at European ports have become prevalent. In this paper, a conceptual framework was created to explore the perceived barriers that prevent compliance with MSGs. To verify the conceptual framework, empirical data were collected using a mixed-methods approach, which was comprised of interviews with national experts and a survey of 47% of Swedish ports involved in the shipping of goods. According to the presented framework, the perceived barriers of Swedish ports to compliance with MSGs were linked to collaborations within the Swedish Maritime Security stakeholder network, available resources and educational knowledge about security culture. In addition, the perceived barriers of smaller ports were linked to the adaptation to MSGs at different levels and the absence of specific tools of maritime security management. Due to an increased interest in international shipping of goods, this paper is currently one of few that addresses the barriers to compliance with MSGs. Moreover, the paper presents a general conceptual framework, novel managerial implications and recommendations for future research. 相似文献
5.
This study explores the use of localized necking for failure modeling in maritime crash analysis, using large shell elements. The assumption that the failure of a large shell element occurs simultaneously with the onset of localized necking is revisited. This study particularly investigates the numerical implementation of the localized necking condition and its implications on the results of ship collision analysis involving not only plate rupture but also various failure mechanisms such as the crushing and tearing of web girders, stringers, and their intersections. Through a series of large-scale collision simulations, the effects of bending deformation on the initiation of necking, non-proportional loading paths, and ductile fractures not preceded by localized necking, are investigated. It is demonstrated that a localized necking-based fracture model provides a reasonable, relatively mesh-insensitive estimate of the onset of fracture in the outer hull panels; however, fracture propagation is very sensitive to the numerical implementation of the necking and fracture model, especially for the cases involving the crushing of web frames and stringers. 相似文献
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根据中小型水利工程项目分散、投资小、工期短的特点,介绍了当前中小型水利项目施工劳务管理的现状,分析当前中小型水利工程劳务市场建立困难的原因,提出在当前形势下中小型项目施工企业须遵守国家的法律法规,杜绝违法劳务分包,推进劳务市场的建立、成熟和完善。 相似文献
8.
介绍了非线性动力学理论在船舶横甩研究中的应用,总结了近年来横甩研究的主要方法和结论,最后指出了横甩问题尚需深入研究的几个方面。 相似文献
9.
肖旭 《大连铁道学院学报》2002,23(1):91-93
章从理论上分析了不完全竞争对经济过剩的影响,指出,当家庭在劳动市场上面临数量约束时,将导致对消费品需求减少,从而存在从劳动市场到产品市场的溢出效应;当厂商在商品市场上面临数量约束时,将导致对劳动需求减少,从而又存在从产品市场到高层到劳动市场的溢出效应,章从而个市场的关系出发,分析了乘数发挥作用的前提条件。 相似文献
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