多级航道通过能力的数学模型研究

航道承载着具有OD点对的船舶组成的交通流,航道通过能力表示航道的交通承载能力。将多级航道中各港口视为网络模型中的节点,各航段视为网络模型中的连线,考虑与航道通过能力密切相关的航道货流OD结构,建立了以任意起点港和终点港之间货流量为变量,各货流量或货物周转量之和最大为目标函数,航段通过能力、港口设计通过能力及碍航建筑物通过能力为限制条件的OD结构网络模型,来测算多级航道通过能力。     

三峡库区大型散货出口码头结构型式和装卸工艺

三峡库区具有特殊的水文地质条件,散货出口码头结构型式和装卸工艺相对落后。文章结合重庆某专用矿石出口码头的建设,提出3种适用于大型散货出口码头的结构型式和相应的装卸工艺。研究认为架空直立墩式结构及相配套的装卸工艺具有占用岸线短、使用方便、装卸效率高和造价低等优点,适宜在三峡库区大型散货出口码头建设中推广应用。     

Formulating cargo inventory costs for liner shipping network design

This study examines how to incorporate the inventory costs of containerized cargoes into existing liner service planning models such that the designed networks could be improved while not causing extra modeling/computational burden. Two approaches are compared: (i) not considering the inventory costs at all and (ii) incorporating the inventory costs associated with onboard time and those related to transshipment by assuming a fixed connection time. The two models are compared with the ideal model capturing the exact inventory costs on a route choice problem and a capacity planning problem based on extensive randomly generated and practical numerical experiments. The results show that: first, ignoring the inventory costs in service planning models may lead to network design with much higher costs (poor network design decisions); second, in service planning models assuming weekly frequency, the inventory costs associated with onboard time could be formulated exactly, and those related to the connection time of weekly services could be approximated by assuming fixed connection time of 3.5 days for ports with 1 day’s minimum connection time and 4.5 days for ports with 2 days’ minimum connection time.     

30000方LNG船液货舱传热分析

针对国内第一艘在建中小型TYPE C型LNG船,提出了其货舱温度场的分析模型。基于工程传热学的原理,应用VBA计算程序,计算得到了各关键点的温度分布与热流密度,并与液货罐供应商TGE集团的报告对比。结果表明：若参数值相同,则计算值与报告值完全吻合。这说明,计算模型正确。这能够为TYPE C型液货舱的传热分析尤其是控制LNG蒸发率提供有力的指导。     

18万吨散货船船舶管系设计研究

以好望角型散货船为依托研究船舶管系的设计及计算,着重阐述货舱舱底水、压载、艏部污水及货舱进水等对船舶航行安全至关重要的四个系统,对系统组成、设备容量计算、设计要领及规范要求等进行研究,本着降低成本完善系统功能的原则完成设计,为今后类似船型的设计提供了参考依据。     

Wave responses of a coastal cargo ship consisting of unit modules

This article discusses the dynamic responses of a coastal cargo ship that consists of unit modules with advance forward speed in waves. We introduce a simple way of connecting the modules that has enough capability to link the modular parts of the ship as a unified whole. The flexible connection consists of male and female rubber fenders with additional pretensioned ropes. This kind of connection system is proposed for use in coastal regions with relatively calm waters wherein the modular ship can move at a moderate speed. The modules are assumed to be rigid compared to the connections. Computations were performed to investigate the vertical elastic responses of four modules connected end-to-end with the assumption that in the simple hinge, no gaps occur in the flexible rubber connections between adjacent modules. A simple method, which is an extension of the computational analysis we reported previously, is presented to study the hydroelasticity and rope tension forces of the modular ship with forward speed in waves. Experiments with a three-dimensional model at Froude numbers of 0 and 0.16 in head waves were performed to evaluate the effectiveness of the calculation method. In the experiments, deflections for each part were measured using calibrated potentiometers. Force transducers were used to measure the rope tension force between the modules of the articulated cargo ship. Some slight differences were observed, but generally the calculated results showed the same trends as the experimental values.     

中国沿海港口国际中转研究

在回顾目前内支线货物退税操作流程、中国沿海及附近国家港口中转货的情况、中国沿海港口通航条件的现状、助航设备的发展及相关研究成果的基础上,分析目前存在的问题并提出解决方案,对于中国沿海港口的定位和国际航运中心的建设具有一定的参考价值。     

Panama Canal expansion: alleviating global climate change

This paper quantifies likely changes in greenhouse gas emissions which contribute to anthropogenic climate change, resulting from the expansion of the Panama Canal and the consequent increase in ship-borne commercial transportation from east Asia to the US east coast. Ocean transportation offers higher fuel economy and lower pollutant emissions compared with land transport. Additionally, truck and train transportation of cargo along the US land bridge threatens to overwhelm existing highway and rail systems and limit economic growth. The alternate transportation route for easterly transit of the Panama Canal will reduce overland traffic congestion and enhance economic development by maintaining freight flow efficiency.     

LNG船液货装卸系统分析软件平台研究

提出了一种基于VC＋＋平台和数据库技术的LNG船液货装卸系统设计及分析的软件平台系统,详细介绍了其内容、结构和实现方法。该系统配有与管路阻力计算相关的管道、阀件、液货舱、附件等的数据库,能够按目标船的装卸要求,直接组态设计液货装卸系统管网系统。设计人员可以在每一个模型设计完成后直接进行优化并确定液货泵的排量、压头、液货管路的管径、长度等设计信息,仿真计算装卸过程中各时间段上的的流量、节点压力、剩余舱内液体容积等各项参数。不仅简化了液货装卸系统的设计过程和计算校核的时间,而且更加方便灵活。     

散杂货堆场平面图系统的开发

针对港口物流企业散杂货堆放不规则的特点,应用数据库技术和 VB6． 0平台,设计了一种能直观 反映散杂货外形尺寸及堆放位置的堆场平面图系统,以实现堆场平面图的管理,达到充分利用堆场,提高通过能力 的目的。     

A nested logit model of mode choice for inland movement of export shipments: A case study of containerised export cargo from India

Predominance of containerised mode of transport for export of general cargo has influenced the mode choices on the inland segment. Prior to containerisation the general cargo for export moved to ports invariably on road in break bulk form. Growth of containerisation led to development of inland terminals enabling an exporter to obtain export clearance at the inland points. This process facilitated an exporter to move cargo either in break bulk or in containerised form, and as inland terminals facilitated aggregation an exporter could move cargo either by road or rail. Thus containerisation increased the inland transport options for an exporter from one to three. The paper develops discrete choice models in the Indian context for inland movement of containerised export cargo. Primary data was collected from 124 export firms through a structured questionnaire. This data is supplemented with data from transport firms and terminal operators. Using the above data, a nested logit model with rail container and road truck in one branch was found to predict the mode choice behaviour best. Amongst the transport attributes, total cost and total transit time were found to be influencing the mode choices significantly. The study however did not find the effect of reliability and loss and damage significant. In addition, the model also predicts that non transport attributes - like the percentage of letters of credit that materialise with inland way bills and the value of export benefits that materialise after export - are important in the mode choice decision.     

Independent Baltic State ports: the outlook for commercial viability?

This study employs the 'shift-share' technique to assay the status of seaport in the newly-independent Baltic States in terms of their prospects for commercial viability. It delineates the material, economic and political conditions confrontiger port managers and policy makers in these states. Each must deal with the consequences of disruption of long-standing trade dependencis and the transition from opeation within 'the Rouble zone' to free market structures integrated with western trade systems. These problems are compounded by Russia's appaent policy decision to re-route transit cargo away from Baltic State ports, the traditional 'window on the West'. to ports located in Russia itselft. Disruption of traditional hinterlands and transit cargo volumes for Baltic State ports will impact their ability to invest in essntial modernization and expansion projects, necessitated by emerging competitive pressures. It is speculated that one potential strategy available for capturing a niche and reclaiming the role of the East-West commercial bridge is through participation in the Trans-Siberian Railway 'land-bridge' trade.     

32000DWT散货船货舱段结构强度分析

利用MSC／Patran、MSC／Nastran软件分析了32000DWT散货船货舱段强度。给出了外载荷的计算方法和边界条件的施加方法,计算了典型的3种工况下32000DWT散货船的强度。通过有限元强度分析得到的结论可用于散货船的结构设计和优化。计算结果表明,本船的结构强度满足规范要求。     

Research on probability distribution of port cargo throughput

In order to more accurately examine developing trends in gross cargo throughput, we have modeled the probability distribution of cargo throughput. Gross cargo throughput is determined by the time spent by cargo ships in the port and the operating efficiency of handling equipment. Gross cargo throughput is the sum of all compound variables determining each aspect of cargo throughput for every cargo ship arriving at the port. Probability distribution was determined using the Wald equation. The results show that the variability of gross cargo throughput primarily depends on the different times required by different cargo ships arriving at the port. This model overcomes the shortcoming of previous models： inability to accurately determine the probability of a specific value of future gross cargo throughput. Our proposed model of cargo throughput depends on the relationship between time required by a cargo ship arriving at the port and the operational capacity of handling equipment at the port. At the same time, key factors affecting gross cargo throughput are analyzed. In order to test the efficiency of the model, the cargo volume of a port in Shandong Province was used as an example. In the case study the actual results matched our theoretical analysis.     

Risk assessment framework for exposure of cargo and ports to natural hazards and climate extremes

There is an increase in risks and catastrophic losses in maritime transport including ports and cargo. Significant losses have been associated with large scale natural hazards, such as earthquakes, tsunami, cyclones, and other extreme weather events. This paper identifies the main gaps in understanding maritime risks in transportation research. The gaps are attributed to insufficient empirical work available from the maritime transport and logistics research community to guide multi-risk and natural hazards impact assessment on seaport and cargo. In addition, disaster studies communities have barely made adequate efforts to understand and assess port and cargo risks arising from multi-hazards and disaster events. This paper examines existing conceptual frameworks concerning exposure and risk assessments of natural catastrophe’s impacts. Furthermore, the paper identifies trends and gaps in risk assessment frameworks in the field of disaster studies that can be beneficial for maritime risk research. The authors propose a new risk assessment framework that can guide future research and multi-hazard risk assessment processes at different scales of maritime risks.     

液化天然气船货舱内部压力研究

LNG船的货舱内部压力应按照IGC规则的要求进行计算。其中,无因次加速度合成方法和横稳心高(GM值)是影响货舱内部压力的重要因素。IGC规则允许采用2种方法来进行无因次加速度的合成:二维加速度椭圆合成法和三维加速度椭球合成法。针对某22万m3薄膜型LNG船,编制了载荷计算电子表格,比较了这2种加速度合成方法导致的货舱内部压力的差异,电子表格计算结果与船级社相应计算软件的结果相一致。另外,就GM值对货舱内部压力的影响进行了讨论。     

大型散货船船体损伤事故及对策研究

该文对近年来发生的大量大型散货船船体损伤及沉船事故的结构力学原因及管理原因进行了全面研究分析，指出了船体结构设计缺陷部位和管理不善的要点。具体描述了破损发展过程。提出了新散货船船体结构型式的改进方案；提出了现有散货船船体结构的加强措施；提出了加强管理的具体意见。     

Assessment criteria for the sustainable competitive advantage of the national merchant fleet from a resource-based view

To determine the competitive advantage of the national merchant fleet, based on the resource-based view, we collect competitive advantage assessment factors from literature, and use the analytic hierarchy process methodology to compare the importance of assessment dimensions and variables. The article's conclusions include a recommendation that the government review the current allocation of resources and implement measures to reinforce the national merchant fleet. This study's findings can be summarized as follows: (1) Criteria dimensions are ranked in the order of competitive strength, organizational capability, tangible assets, and intangible assets. (2) Criteria variables can be ranked in the order of freight revenue, cargo loading ratio, accuracy of shipping schedule, dead weight tonnage, number of vessels, standard of customer service, reputation of shipping company, cargo transportation volume, gross tonnage, sailing frequency, shipping knowledge, fleet specialization, number of crewmen, and fleet technological level. (3) The government should review existing maritime regulations and measures in order to formulate specific and transparent policies, and seek to adopt optimal alternatives from other countries concerning such issues as tonnage tax, bilateral income tax reduction or exemption agreements, second-registration mechanisms and shipbuilding basis, etc.     

Impact of container chassis management practices in the United States on terminal operational efficiency: An operations and mitigation policy analysis

Existing policies designed to mitigate the environmental and social impacts of truck queuing at maritime terminals often focus on congestion problems outside of the terminal gate, targeting a reduction in the waiting and turn time of trucks as the measure of success. This paper evaluates the impact that intra-terminal truck and equipment movements have on the terminal’s overall performance and the implications that these movements have on the effectiveness of current mitigation policies. Through a simulation of terminal processes occurring at Southern California ports it is shown that measures driving reductions in truck turn times impose greater operational loads on terminal equipment, essentially transferring savings in truck turn time rather than eliminating it in terms of the overall system. Consequently, the paper finds that total truck and cargo handling equipment movement and operational time constitutes a more accurate measure of the effectiveness of policies seeking to mitigate the impacts of truck operations at marine terminals.     

散货船破舱稳性计算研究及软件实现

阐述近年来航运业面临的散货船海损事故,根据SOLAS修正案"散货船的安全措施"及"货船分舱和破舱稳性"的条款的要求,对船舶分舱及破舱稳性的计算方法进行研究。利用Visual Basic编制了破舱稳性计算软件,并介绍了其功能。