船舶照明系统的故障分析与检查

船舶照明系统的故障分析和及时排除对保证船舶的安全航行和船员的安全有着十分重要的作用。此文结合实际，对船舶照明系统的短路、接地和断路故障的现象、产生原因和排除故障的方法做了较为详细的介绍；根据STCW公约的要求，对船舶照明系统的维护周期和内容作了阐述，并着重介绍了船上荧光灯照明线路常见故障的分析方法。     

大功率LED照明系统电磁兼容问题的研究

文中介绍了大功率LED照明系统的发展现状及前景,详细描述了该系统的主要组成模块及其功能。并通过电磁干扰的三要素:干扰源、传输途径和敏感设备对此系统的电磁干扰情况进行了说明。     

新型船用照明灯具的研制

在舰艇特别是潜艇内部,照明系统是十分重要的部分.由于对舰艇安全性和艇员的舒适性具有影响,内部照明对于潜艇整体有着多方面的效应.本文论述了采用新型LED照明技术为潜艇设计的1个具有高可靠性和免于维护的照明系统以及相关的设计实现.装备了这一优化集成的照明系统之后,潜艇供电、照明系统工作负荷和发生故障的可能性得到降低.     

港口视频监控系统的防雷措施

介绍雷电对沿海港口视频监控系统的危害形式和途径，结合工程实例，提出港口视频监控系统防御雷电灾害的措施。     

LED灯具在船舶照明及智能照明系统中的优势应用

相较传统照明方式,LED具有寿命长、发光效率高、安全性高、体积小、环保等特点。LED的色温丰富、亮度可控制,是目前替代传统照明灯具的一种选择,随着智能船舶概念的兴起,LED在船舶智能照明系统中的应用前景十分广阔。     

新一代大功率中速柴油机增压系统的预研

文中提出了新一代大功率中速柴油机采用缸内膨胀回收功率系统的设想,讨论了该系统的特性和可行性,并简要介绍了MPC系统优化设计的计算方法,以及全工况优化控制的研究结果。     

一种新型港口自动化照明系统的设计与实践

港区照明用电是港口电力成本中一个重要的组成部分.照明系统的设计方案关系到港口照明系统的品质.不同的方案,造价不同,建成投运后的电力成本和维护成本也不同.照明系统的经济性指标和技术性能也就不同.港口照明系统技术经济性体现在设计方案中.基于这样一个认识,广州港在新沙8～10泊位的供电及照明系统改造的设计过程中,在注重照明系统的技术与经济性方面,做了一些有意义的尝试.     

舰船推进系统－－多种动力的联合系统

论述了联合推进系统，并且对舰船推进系统的过去、现在、未来进行详细讨论。     

云南新一代多普勒天气雷达业务系统防雷

气象业务系统的雷电防护工作是气象技术保障工作的重要组成部分,我国自1998年开始在全国布网的新一代多普勒天气雷达业务系统,云南省分别在昆明、昭通、文山、思茅、德宏、丽江等地布设.自2000年起,我省布设的新天气雷达逐步投入业务运行,经过初验和几个雷雨季节的考验,雷达工作运行正常.     

自升式海上油田多功能支持平台的三滑移系统

主要介绍了国内首制的＂海洋石油281/282＂平台的三滑移系统,包括三滑移液压系统、滑移系统的主要结构。相对于目前其他海上平台两滑移系统,三滑移系统具有实现平台多功能、节约钻井模块搬迁资源、增大可变载荷等技术创造性和先进性。     

Locomotion by mechanical pectoral fins

The objectives of this study were the development of a new device for maneuvering an underwater vehicle using the mechanism of a fish swimming, an experimental and theoretical analysis of the hydrodynamic characteristics of the device, and its application to maneuvering a fish robot. Observations and experimental analysis of the pectoral fins of a black bass (Micropterus salmoides) revealed that the locomotion of the fish, such as swimming forward at low speed, swimming backward, and turning in a horizontal plane is generated by using a combination of a feathering motion and a lead-lag motion of the pectoral fins. A mechanical pectoral fin making a feathering motion and a lead-lag motion generates a thrust force in a range of phase differences between both motions. The unsteady vortex lattice method, including the effect of viscosity, can express fairly well the unsteady forces acting on the mechanical pectoral fin in the range of phase differences where it exerts the thrust force. The fish robot, consisting of a model fish body and a pair of mechanical pectoral fins, can not only swim forward and turn in almost the same position, but can also swim in a lateral direction without changing the yaw angle. Translation of an article that appeared in the Journal of The Society of Naval Architects of Japan, vol. 182 (1997): The original article won the SNAJ prize, which is awarded annually to the best papers selected from the SNAJ Journal, JMST, or other quality journals in the field of naval architecture and ocean engineering.     

Vibration-assisted decommissioning of a slip joint: Application to an offshore wind turbine

An alternative option to the traditional grouted joint for wind turbines is a direct steel-to-steel connection, also known as slip joint. In a recently published work, a proof of concept of a vibration-assisted installation and decommissioning technique of a slip joint was illustrated. Leveraging on the obtained results, the current study shows for the first time a decommissioning campaign carried out using a vibration-assisted technique applied on a prototype hydraulic wind turbine tower located in the North Sea, and connected to the monopile through a slip joint. The key aspect of the dismounting procedure is a priori knowledge of the resonance frequency clusters corresponding to the slip joint’s cross-sectional modes. Therefore, field hammer tests and experimental modal analysis were carried out inside the wind turbine tower. The identified frequencies and mode shapes were then compared with numerical ones estimated by a finite element model of the investigated structure. The comparison showed that a set of frequency clusters can be directly selected from a detailed numerical model. The preparatory work of the slip joint decommissioning was then executed by installing electric shaker devices, based on the dynamic identification results, and hydraulic jacks mounted inside the wind turbine tower. A first decommissioning trial was carried out in May 2019, while the final decommissioning was performed in August 2019. After analysing the measurements of the hydraulic pressures, displacements and excitation frequencies during the decommissioning campaigns, the results showed that it is possible to disconnect the slip joint if, in combination to a vertical static force, one of the identified cross-sectional mode shapes is excited. The vibration-assisted decommissioning proved to be a successful technique to dismount the connection in a controlled and straightforward manner.     

船舶弃船决策系统分析

当船舶发生海难事故后,船舶弃船时机的正确决策关系到船舶安全尤其是海上人命安全,文中试运用决策理论与技术以及系统理论分析了该决策系统的目标与准则、决策环境、决策体制与决策者、决策方案等要素,以及这些要素的相互联系,对弃船时机的正确选择做一个初步分析,为进一步研究奠定一些基础。     

Optimal reefer slot conversion for container freight transportation

Given a fleet of container ships of varying capacity, a cost-efficient approach for improving fleet utilization and reducing the number of delayed containers is to optimize the sequence of container ships in a given string, a problem which belongs to the large ship-deployment class. A string sequence with ‘uniformly’ distributed ship capacity is more likely to accommodate a random container shipment demand. The number of one’s total ship slots acts as a gauge of the capacity of the container ships. Meanwhile, there are two types of ship slots: dry slots and reefer slots. A dry slot only accommodates a dry container, while a reefer slot can accommodate either a dry or a reefer container. The numbers of dry and reefer slots for ships in a string are different. Therefore, in this study, we propose a model that considers both dry and reefer slots and use it to elucidate the optimal ship-deployment sequence. The objective is to minimize the delay of dry and reefer containers when the demand is uncertain. Furthermore, based on the optimal sequence deduced, the study also investigates the need to convert some dry slots to reefer slots for the container ships.     

鹰式装置“万山号”总体设计概述

100kW鹰式波浪能发电装置工程样机“万山号”为一基多体式设计,四个鹰式吸波浮体共享水下附体、能量转换系统及锚泊系统。通过一系列模型试验,获得最优负载。根据模型试验结果,确定了实海况装置的出力参数。为稳定地获得标准电力与试验数据,设计了涵盖蓄能、发电、变电模块、电气监控模块、电源模块、浮态监控模块和岸基模块等多个模块的电气系统。通过锚泊系统计算与分析,确定了锚泊系统的选型参数。     

三体船型PCC风荷载的实验性研究(英文)

In recent years, demands for car transportation by a ship have been increasing with favorable economic conditions in auto sector, and the need of a pure car carrier (PCC) has grown quickly. A PCC needs huge parking space but smaller displacement since a car is comparatively light for its volume. As a result, almost all PCCs have wide breadth, shallow draft and huge structure above the water surface. These features cause some technical issues of a PCC, like lack of stability, effect of strong winds on its resistance, difficulty of course keeping in rough seas, difficulty of berthing in strong winds, and so on. To overcome these technical issues, one of the authors has proposed a new concept for a PCC. This is a trimaran PCC which has very limited transverse bulkheads in the center hull by using two side hulls as fenders. In the present research, wind forces acting on a scale model of the trimaran PCC were measured in the towing tank with a wind generator at Osaka Prefecture University. Furthermore, in order to clarify the characteristics of wind pressure on the trimaran, height and width of tunnels which are between a main hull and side hulls were changed. And then, in order to imitate a real ship, we used wind reduction technology of corner-cut design for accommodation house of the ship. Moreover, the wind pressure acting on the trimaran was compared with that on a mono-hull PCC. Using these experimental and theoretical results, an estimation method of wind pressure acting on the trimaran PCC is deduced.     

Numerical analysis on free surface waves and stern viscous flow of a ship model

This paper deals with numerical techniques for computing the viscous flow past a ship hull with and without a free surface using a Reynolds-averaged Navier-Stokes solver with global conservation. In the first technique, a coarse grid is used to find an approximate solution to the free surface problem. Interpolation of a fine grid is subsequently carried out, and a more exact solution, particularly in the boundary layer and wake, is obtained. In the second technique, a modified Baldwin-Lomax model is introduced to compute the viscous flow with and without a free surface. These numerical techniques are applied to simulations of the flow around a Series 60 and an SR196C ship model. The results are compared with measurement data, and the usefulness of the numerical techniques is demonstrated.     

Integrated optimisation design of a dynamic umbilical based on an approximate model

An optimised design of a dynamic umbilical requires an extreme cross-sectional stress to be maintained within an allowable limit and a fatigue life to be guaranteed to be sufficient. It should be noted that a dynamic umbilical is a typical geometric bi-scale structural system. It consists of a local cross-sectional scale and a global configuration scale, which are significantly different in terms of geometric sizes. In this study, we established an approximate model to achieve an optimised design of the dynamic umbilical by considering the parameters of local cross-sections and global configurations simultaneously. The design variables of a dynamic umbilical are independently identified and defined at both local sectional and global configuration scales in the approximate model. Furthermore, we selected the maximum tension strain and the maximum bending moment, for covering local and global properties, as the objectives to be minimised. The approximate model was observed to be effective in integrating the local and global responses into one loop so that the computational efficiency could be significantly increased. We implemented the optimisation framework on a dynamic umbilical with a lazy-wave configuration, which is considered to be a basis for a case study. Furthermore, we verified the feasibility and effectiveness of the integrated optimisation strategy by numerical simulations. Moreover, we compared the optimised dynamic umbilical properties with those without optimisation. It was observed that the fatigue life of the optimised dynamic umbilical was improved significantly, thereby indicating that the integrated optimisation methodology provides a new model and algorithm for an efficient design of the dynamic umbilical.     

Humpback Whales in Tonga: An Economic Resource for Tourism

The growth of whale-watching internationally has been spectacular. It now occurs in almost 100 countries and is estimated to be worth in excess of U.S.$1 billion each year in revenue. Thus, whales have become valuable as a resource for tourism. The Vava'u island group in the northern part of the Kingdom of Tonga in the South Pacific is an area with a growing reputation as a whale-watching destination. However, the industry is relatively new there and the impacts of whale-based tourism in these islands is, as yet, unknown. In addition, there has been a recent consideration of a return to hunting whales in Tonga. As a result, concerns regarding the value of these animals for tourism and the potential impact of a return to hunting have arisen. Consequently, a study was designed to provide a preliminary assessment of the economic impacts of these animals for the island community. This study estimates that humpback whales may be worth in excess of U.S.$700,000 annually as a tourism attraction and that there is significant potential for future growth. Furthermore, the study shows that current visitors are opposed to any resumption of whaling practices in the islands and that such a move would likely displace large numbers of tourists from Tonga. Thus, it is concluded that a resumption of whaling in Tonga would likely have a significant opportunity cost in terms of lost tourism revenues.     

Three-dimensional numerical wave tank simulations on fully nonlinear wave–current–body interactions

A finite-difference scheme and a marker-and-cell (MAC) method are used for numerical wave tank (NWT) simulations to investigate the characteristics of nonlinear wave motions and their interactions with a stationary three-dimensional body in the presence of steady uniform currents. The Navier–Stokes (NS) equation is solved in the computational domain, and the boundary values are updated at each time-step by a finite-difference time-marching scheme in the frame of a rectangular coordinate system. The fully nonlinear kinematic free-surface condition is satisfied by the marker–density function technique developed for two fluid layers. The incident waves are generated from the inflow boundary by prescribing a velocity profile resembling the motions of a flexible flap wavemaker, and the outgoing waves are numerically dissipated inside an artificial damping zone located at the end of the tank. Using the NS–MAC NWT, nonlinear wave and current interactions around a stationary vertical truncated circular cylinder are studied, and the results are compared with the experimental results of Mercier and Niedzwecki, a time-domain NWT based on linear potential theory, a fully nonlinear NWT, and a second-order diffraction computation. Received: July 3, 2001 / Accepted: September 25, 2001