Coupled Dynamic Response Analysis of A Multi-Column Tension-Leg-Type Floating Wind Turbine

This paper presents a coupled dynamic response analysis of a multi-column tension-leg-type floating wind turbine (WindStar TLP system) under normal operation and parked conditions. Wind-only load cases, wave-only load cases and combined wind and wave load cases were analyzed separately for the WindStar TLP system to identify the dominant excitation loads. Comparisons between an NREL offshore 5-MW baseline wind turbine installed on land and the WindStar TLP system were performed. Statistics of selected response variables in specified design load cases (DLCs) were obtained and analyzed. It is found that the proposed WindStar TLP system has small dynamic responses to environmental loads and it thus has almost the same mean generator power output under operating conditions as the land-based system. The tension mooring system has a sufficient safety factor, and the minimum tendon tension is always positive in all selected DLCs. The ratio of ultimate load of the tower base fore-aft bending moment for the WindStar TLP system versus the land-based system can be as high as 1.9 in all of the DLCs considered. These results will help elucidate the dynamic characteristics of the proposed WindStar TLP system, identify the difference in load effect between it and land-based systems, and thus make relevant modifications to the initial design for the WindStar TLP system.     

导管架平台拆除过程稳定性及影响因素分析

现有服役海洋平台正逐步走向老龄化,海洋平台拆除成为海洋工程新的经济增长点。针对达到服役年限的导管架平台,基于数值分析方法模拟拆除过程,开展平台在不同拆除阶段和环境载荷等参数下的稳定性及影响规律研究。基于钢结构整体稳定性理论,以导管架平台拆除过程中顶点位移为参考,定义导管架平台拆除作业稳定性指标,提出拆除作业阶段划分方法,通过分析导管架平台在不同影响因素作用下拆除过程稳定性响应,给出拆除作业建议。选取我国南海某4裙12腿进行实例分析,结果表明:主桩腿对导管架平台起决定性承载作用,拆除部分主桩腿后需要引入外部支撑力,以保证拆除作业安全进行;拆除构件越多,来浪方向和环境载荷大小对平台影响越加显著。研究结果可为导管架平台拆除作业提供参考。     

甘肃省人工增雨防雹作业决策指挥系统

“甘肃省人工增雨防雹作业决策指挥系统”实现了作业装备的网络化管理,它以先进的监测系统为基础,依靠现代化的通信网络,应用3S集成技术,开发以甘肃省详细地理信息为背景,集成应用多种信息资料的人工影响天气地理分析平台,通过手机短信实现作业条件的自动报警和发布作业指令。     

Compliance costs and the small fisher: A study of exiters from the New Zealand fishery

Over 3000 predominantly small-scale fishers have exited the New Zealand's quota management system (QMS) between its inception in 1986 and 2000. This study, based on the Ministry of Fisheries database and a questionnaire sent to the exiters, establishes that compliance costs in general, and those specifically related to the QMS, were one of the most consistent reasons for exit. Uncertainty about future QMS policy and the high cost of quota were also significant factors. It appears that the small fishers’ perception of high compliance cost can be supported by industry data.     

DZJ2激光垂准仪使用方法及指标的校正

介绍了DZJ2激光垂准仪的性能及基本指标的校正方法,为用户在使用DZJ2激光垂准仪过程中几种基本指标参数的校正提供参考.     

Ethanol Production: Energy and Economic Issues Related to U.S. and Brazilian Sugarcane

For a thorough and up-to-date evaluation of all the fossil energy costs of ethanol production from sugarcane in both the U.S. and Brazil, every energy input in the biomass production and ultimate conversion process must be included. In this study, more than 12 energy inputs in average U.S. and Brazilian sugarcane production are evaluated. Then in the fermentation/distillation operation, nine more fossil fuel inputs are identified and included. Some energy and economic credits are given for the bagasse to reduce the energy inputs required for steam and electricity. Based on all the fossil energy inputs in U.S. sugarcane conversion process, a total of 1.12 kcal of ethanol is produced per 1 kcal of fossil energy expended. In Brazil a total of 1.38 kcal of ethanol is produced per 1 kcal of fossil energy expended. Some pro-ethanol investigators have overlooked various energy inputs in U.S. and Brazilian sugarcane production, including farm labor, farm machinery, processing machinery, and others. In other studies, unrealistic low energy costs were attributed to such energy inputs, as nitrogen fertilizer, insecticides, and herbicides. Both the U.S. and Brazil heavily subsidize ethanol production. Thus billions of dollars are invested in subsidies and this significantly increases the costs to the consumers. The environmental costs associated with producing ethanol in the U.S. and Brazil are significant but have been generally overlooked. The negative environmental impacts on the availability of cropland and freshwater, as well as on air pollution and public health, have yet to be carefully assessed. These environmental costs in terms of energy and economics should be calculated and included in future ethanol analyses so that sound assessments can be made. In addition, the production of ethanol in the U.S. and Brazil further confirms that the mission of converting biomass into ethanol will not replace oil. This mission is impossible. General concern has been expressed about taking food crops to produce ethanol for burning in automobiles instead of using these crops as food for the many malnourished people in the world. The World Health Organization reports that more than 3.7 billion humans are currently malnourished in the world—the largest number of malnourished ever in history.     

WZ25-20钻进机构操作系统的程序设计

介绍了应用单片机构成的一种钻进机构操作系统的程序设计。     

柴油机轴承设计、使用和维修的几个问题

在保证轴承安全而经济的运转条件下,轴承装配间隙取最小值,根据流体润滑理论,选择合适的润滑油;对于厚壁轴瓦,在磨合之后应调整到运转间隙。这样就可以充分利用轴承的使用寿命。     

海洋观测中的实时操作系统分析研究

海洋观测是获取海洋环境信息的重要方式,实时、可靠的操作系统是海洋观测中信息采集与处理系统的重要组成部分。实时操作系统计算的正确性不仅取决于计算的逻辑正确性,还取决于产生结果的时间。该系统具有高精度计时系统、多级中断嵌套机制和实时调度机制,这些特性保证任务在规定的时间内完成。文中对三个典型的操作系统(Wind River公司的Vx Works、BRTT公司的Antelope和开源的RTLinux)进行研究,并从功能、关键模块以及优缺点等方面进行分析论证,详细阐述了实时操作系统的功能特性以及实时操作系统在相关领域应用的重要性。     

Payments for Ecosystem Services (PES) in the face of external biophysical stressors

Economic instruments such as Payments for Ecosystem Services (PES) schemes are increasingly promoted to protect ecosystems (and their associated ecosystem services) that are threatened by processes of local and global change. Biophysical stressors external to a PES site, such as forest fires, pollution, sea level rise, and ocean acidification, may undermine ecosystem stability and sustained ecosystem service provision, yet their threats and impacts are difficult to account for within PES scheme design. We present a typology of external biophysical stressors, characterizing them in terms of stressor origin, spatial domain and temporal scale. We further analyse how external stressors can potentially impinge on key PES parameters, as they (1) threaten ecosystem service provision, additionality and permanence, (2) add challenges to the identification of PES providers and beneficiaries, and (3) add complexity and costs to PES mechanism design. Effective PES implementation under external stressors requires greater emphasis on the evaluation and mitigation of external stressors, and further instruments that can accommodate associated risks and uncertainties. A greater understanding of external stressors will increase our capacity to design multi-scale instruments to conserve important ecosystems in times of environmental change.