Forging penetration efficiency of steel H13 stepped shaft radial forging with GFM forging machine

The numerical thermal mechanical simulation of radial forging process of steel H13 stepped shaft with GFM (Gesellschaft fur Fertigungstechnik und Maschinenbau) forging machine was carried out by three-dimensional finite element code DEFORM 3D. According to the effective plastic strain, the mean stress and the mean plastic strain distribution of the radial forging, the forging penetration efficiency (FPE) was studied throughout each operation. The results show that the effective plastic strain in the center of the forging is always greater than zero for the desirable larger axial drawing velocity. The mean stress in the center of the workpiece is proposed to describe hydrostatic pressure in this paper. There is compressive strain layer beneath the surface of the workpiece to be found, while there is tensile strain core in the center of the workpiece. These results could be a valuable reference for designing the similar forging operations.     

Research on Energy Efficiency Design Index for Sea-going LNG Carriers

This paper describes the characteristics of liquefied natural gas （LNG） carriers briefly. The LNG carrier includes power plant selection, vapor treatment, liquid cargo tank type, etc. Two parameters fuel substitution rate and recovery of boil of gas （BOG） volume to energy efficiency design index （EEDI） formula are added, and EEDI formula of LNG carriers is established based on ship EEDI formula. Then, based on steam turbine propulsion device of LNG carriers, mathematical models of LNG carriers＇ reference line value are established in this paper. By verification, the EEDI formula of LNG carriers described in this paper can provide a reference for LNG carrier EEDI calculation and green shipbuilding.     

上海市道路货运结构的经济适应性评价

分析上海市道路货运结构与国民经济的适应性。采用DEA数据包络分析方法,通过选取国民经济指标及道路货运结构指标,评价上海市道路投入及经济产出的有效性,进而说明上海市现状的道路货运结构与国民经济的适应性。最后,通过模型结果分析上海市道路货运结构中存在的问题,并为道路货运结构的调整提供合理性建议。     

A translog cost function of the integrated air freight business: The case of FedEx and UPS

This paper analyzes the cost structure of the integrated air freight business by means of a translog cost function. This allows to extend knowledge on the supply side and to examine if strategies of integrators are consistent with cost structure. The cost function is based on quarterly time-series data from 1990 to 2010 for FedEx and UPS. A total and a variable model are estimated. In addition, a static as well as a dynamic approach is followed. We find that integrators exhibit strong scale and density economies in the short and the long term. This result is in line with the aggressive expansion and cooperation strategies pursued by integrators. Our results indicate that the concentration in the integrated air freight industry will continue: a concern for industry actors and regulatory agencies.     

Vehicle type choice under the influence of a tax reform and rising fuel prices

Differentiated vehicle taxes are considered by many a useful tool for promoting environmentally friendly vehicles. Various structures have been implemented in several countries, e.g. Ireland, France, The Czech Republic, and Denmark. In many countries the tax reforms have been followed by a steep change in new vehicle purchases toward more diesel vehicles and more fuel-efficient vehicles. The paper analyses to what extent a vehicle tax reform similar to the Danish 2007 reform may explain changes in purchasing behaviour. The paper investigates the effects of a tax reform, fuel price changes, and technological development on vehicle type choice using a mixed logit model. The model allows a simulation of the effect of car price changes that resemble those induced by the tax reform. This effect is compared to the effects of fuel price changes and technology improvements. The simulations show that the effect of the tax reform on fuel efficiency is similar to the effect of rising fuel prices while the effect of technological development is much larger. The conclusion is that while the tax reform appeared in the same year as a large increase in fuel efficiency, it seems likely that it only explains a small part of the shift in fuel efficiency that occurred and that the main driver was the technological development.     

Energy efficiency and time charter rates: Energy efficiency savings recovered by ship owners in the Panamax market

This paper presents the first analysis on how financial savings arising from energy efficient ships are allocated between owners and those hiring the ships. This as an important undertaking as allocation of financial savings is expected to have an impact on the incentives faced by ship owners to invest in more energy efficient vessels. We focus on the dry bulk Panamax segment as it contributes to around 50 Mt (5%) of total CO₂ emissions from shipping in 2007 and therefore its importance in terms of environmental impact should not be neglected. The time charter market represents a classical example of the principal–agent problem similar to the tenant–landlord problem in the buildings sector. We discovered that on average only 40% of the financial savings delivered by energy efficiency accrue to ship owner for the period 2008–2012. The finding that only part of the savings are recouped by shipowners affecting their incentives towards energy efficiency could consequently have implications on the type of emission reduction policies opted at both, global and regional levels.     

船舶涂装冲砂派工精细化研究

精细化管理是现代企业所追求的管理模式,在精细化管理下,员工个人能力得到合理安排,整体工作效率得到提升.冲砂作业是涂装作业中重要一环,其精细化派工的实现有利于涂装效率的提升.本文通过对冲砂作业进行分析,研究了不同因素对冲砂效率影响,其中着重研究了作业环境所造成工作人员不同姿势及其对效率的影响,综合分析冲砂作业在不同姿势下的作业效率,并对涂装设计提出改进建议,从而为精细化派工提供了依据.     

“潮汐式”可变航道方案研究与可行性分析

为提高航道整体通航效率,借鉴道路交通中的先进经验,提出“潮汐式”可变航道的概念.建立一种新型的双向航道分道通航模式,在高峰时段为重交通方向向左扩展航道,同时满足两侧通航需求.提出可变航道实施的方案,分析了可变航道实施的关键技术,即动态时间和动态空间的确定,并指出了这两个参数的进一步研究方向.以长江口深水航道为例,通过两种不同的设计船型对可变航道实施的可行性进行了验证.结果表明,可变航道具有广阔的研究和应用前景.初步研究了可变航道的实施和管理方案,为可变航道未来的实施发展奠定了基础.     

桩基透空式防波堤功效评判

在现有桩基透空堤功效评判研究成果的基础上,结合波浪模型试验和理论计算所得的数据,对现有计算公式进行分析总结,归纳出新的计算公式,在不同波要素、相对入水深度条件下进行验证分析,得出相关的结论供桩基透空堤结构选型参考.     

基于个体与协同效能的两栖攻击舰编队兵力选择模型

针对两栖攻击舰编队舰艇型号的选择问题,从舰艇个体效能和舰艇间的协同效能出发,构建兵力选择指标体系,分别建立了基于个体效能的兵力选择模型和基于协同效能的兵力选择模型。在此基础上,定义选择偏好系数,建立基于个体与协同效能的两栖攻击舰编队兵力选择模型。实例分析表明,该模型可以针对作战任务,灵活选择兵力型号。