关于平行运动护舷设计的思考

平行运动护舷(PM护舷)是近年发展起来的新型护舷,在PM护舷承受偏心靠泊荷载冲击作用时基本上能保持竖直状态,从而减少桩基靠船墩等支撑结构的作用力.由于其结构比传统护舷更复杂,内部机构所承受的荷载也较难确定,在实际应用中曾发生过一些结构破坏.通过对模型试验结果的分析,水面下的锥形封闭式舷鼓可能是造成护舷结构破坏的原因之一.     

The effect of location,mobility and socio-demographic factors on task and time allocation of households

This paper investigates the role of location factors in task and time allocation at the household level. It is hypothesized that, if time constraints are less binding as a result of living in an urban area or owning more cars, spouses engage more often and longer in out-of-home activities and schedule their activities more independently. The hypotheses are tested with logistic and Cox regression models of activity participation and time allocation on a data set collected in the Amsterdam–Utrecht region in the Netherlands. Results suggest that the hypotheses are supported with respect to specific household activity scheduling decisions.     

Prediction of ship steering capabilities with a fully nonlinear ship motion model. Part 1: Maneuvering in calm water

This paper introduces a new method for the prediction of ship maneuvering capabilities. The new method is added to a nonlinear six-degrees-of-freedom ship motion model named the digital, self-consistent ship experimental laboratory (DiSSEL). Based on the first principles of physics, when the ship is steered, the additional surge and sway forces and the yaw moment from the deflected rudder are computed. The rudder forces and moments are computed using rudder parameters such as the rudder area and the local flow velocity at the rudder, which includes contributions from the ship velocity and the propeller slipstream. The rudder forces and moments are added to the forces and moments on the hull, which are used to predict the motion of the ship in DiSSEL. The resulting motions of the ship influence the inflow into the rudder and thereby influence the force and moment on the rudder at each time step. The roll moment and resulting heel angle on the ship as it maneuvers are also predicted. Calm water turning circle predictions are presented and correlated with model test data for NSWCCD model 5514, a pre-contract DDG-51 hull form. Good correlations are shown for both the turning circle track and the heel angle of the model during the turn. The prediction for a ship maneuvering in incident waves will be presented in Part 2. DiSSEL can be applied for any arbitrary hull geometry. No empirical parameterization is used, except for the influence of the propeller slipstream on the rudder, which is included using a flow acceleration factor.     

三足鼎立 经典老爷车对决

40多年前,Triumph TR5,Porsche 911和Alfa Romeo GTV纷纷使出自己的浑身解数,想在动力、天生的竞技综合能力以及人们所接受的1960年代车型风格等方面拔得头筹。如今,哪一台车值得装进你的车库中呢?     

Perceptions of Threats Facing Cabo de Palos - Islas Hormigas MPA and Potential Solutions

Many marine protected areas (MPAs) face a multitude of threats to the ecosystems that they have been established to conserve. This study is based on 111 interviews conducted in 2013–2014 designed to discover the perceptions of stakeholders about the threats, the causes of the threats, and their responses to the threats, to a well-established MPA – Cabo de Palos - Islas Hormigas (CPH-MPA). This MPA was created to safeguard fisheries and the associated artisanal fishers, but over time it has become a tourism “hotspot.” Resilience theory, which incorporates ecological resilience, social resilience, and individual resilience, helps us to analyze stakeholders' responses to threats by categorizing them into passive, adaptive, and transformative responses. We found respondents identified four main threats – over-fishing, excessive scuba diving, pollution, and invasive species; attributed the threats to three main causes – ineffective management, poor environmental stewardship, and climate change; and expressed three kinds of responses – do nothing, adapt, or transform – with a preference for adaptation and (especially) transformation. The lesson of this study is that it shows how, unless drastic action is taken to curb recreational diving activities, the CPH-MPA is in danger of changing from a fishing reserve to a largely unregulated leisure diving venue, which is unlikely to fulfill the requirements of resilience; ecological, social, or individual.     

Conceptualizing Social Outcomes of Large Marine Protected Areas

There has been an assumption that because many large marine protected areas (LMPAs) are designated in areas with relatively few direct uses, they therefore have few stakeholders and negligible social outcomes. This article challenges this assumption with diverse examples of social outcomes that are distinctive in LMPAs. We define social outcomes as inclusive of both social change processes and social impacts, where “social” includes all perceptual or material human dimensions. We draw on five in-depth case studies to report social outcomes resulting from proposed or designated LMPAs in Bermuda, Rapa Nui (Easter Island), Kiribati, Palau, and the Commonwealth of the Northern Mariana Islands & Guam. We conclude: (1) social outcomes arise even in remote LMPAs; (2) LMPA efforts generate social outcomes at all stages of development; (3) LMPAs have the potential to produce outcomes at a higher level of social organization, which can change the scope and type of affected populations and, in some cases, the nature and stakes of the outcomes themselves; (4) the potential for LMPAs to impart distinctive social outcomes results from their unique geographies and/or intersection with high-level politics and policy processes; and (5) social outcomes of LMPAs may emerge in the form of social change processes and/or social impacts.     

A logistics and supply chain management approach to port performance measurement

Although there is widespread recognition of the potential of ports as logistics centres, widely accepted performance measurements for such centres have yet to be developed. The essence of logistics and supply chain management is an integrative approach to the interaction of different processes and functions within a firm extended to a network of organizations for the purpose of cost reduction and customer satisfaction [1]. The logistics approach often adopts a cost trade-off analysis between functions, processes and even supply chains [2]. This approach could be beneficial to port efficiency by directing port strategy towards relevant value-added logistics activities. This paper seeks to show that through conceptualizing ports from a logistics and supply chain management approach, it is possible to suggest a relevant framework of port performance. A proposed framework is tested in a survey of port managers and other international experts.     

The potential for British coastal shipping in a multimodal chain

A strategy to revitalize coastal shipping within Great Britain is investigated. An examination of the regulatory environment shows government, at both the EU and British levels, aware of the environmental benefits of coastal shipping compared to road freight transport, if only mildly supportive in tangible terms. The geography of Great Britain and the modern preference for just-in-time deliveries have severely restricted the ability of coastal shipping to compete effectively with road freight transport. The primary objective of the paper is to investigate whether coastal shipping could be integrated into a multimodal door-to-door supply chain, where it is currently hampered by high costs of transhipment, slow transport speeds, and the incongruity of load sizes between land and sea modes. Integration requires the co-operation of all organizations within the multi-modal supply chain. However, coastal shipping companies have been known to be individualistic and mistrusting of alliances. Therefore, a Delphi study is undertaken to investigate the standpoint of leading managers in such companies towards multimodal integration. The results of the Delphi study indicate that managers are in favour of multimodal developments, in particular cooperation between coastal shipping and road haulage. However, there was agreement that the business is highly competitive, and this may prevent the forms of collaboration required for multimodal systems. The secretive nature of the coastal shipping sector could impede joint marketing to promote a mode of transport that is often 'invisible' to shippers. There was little consensus on the relationship that should exist between coastal shipping and ports, a topic worthy of further investigation.     

Governance for Sustainable Coastal Futures

The mobile nature of soft coasts means that coastal communities face uncertainty in their property values and peace of mind when the existing coastal defense is lowered or removed. The acceptance by the U.K. government that coastal realignment in areas of low population density and limited ecological value is unavoidable means that the current state of affairs, where coastal residents have broadly come to assume that they will be defended if they make enough fuss, cannot continue. The government is currently unwilling to confront this consternation and continues to refuse to pay compensation for lost property value. This is creating an outcry over loss of fairness of treatment. This dispute raises important questions of governance for coastal change. This participatory research project worked closely with English Nature, North Norfolk District Council, local residents associations, the Environment Agency, and the Department for Environment, Food and Rural Affairs. What emerged in the analysis were unresolved tensions between national strategic frameworks, emerging planning arrangements, changing economic assessments, and the desirability of delivering, through a number of public and voluntary agencies, local flexibility in participation and in coastal design. This article reports on the research process, the challenges for coastal governance, and the scope for creative partnerships between science, planning, policy delivery, and public acceptance.