基于可靠性为中心的航空保障系统特种装置维修决策研究

目的研究航空保障系统维修决策。方法通过对俄罗斯航母航空保障系统特种装置主要功能和系统组成的分析,探索特种装置维修技术保障特点,并以可靠性为中心的维修理论,研究航空保障特种装置重要功能部件,分析其故障模式及产生原因。结果通过RCM进行逻辑决断,确定了航空保障特种装置预防性维修工作类型、维修等级和维修间隔期等。结论 RCM可有效应用于航空保障特种装置维修分析中,为机关决策提供理论参考。     

战场电磁兼容预测中的干扰发射机模型研究

目的建立战场电磁兼容预测中的电磁干扰发射机数学模型。方法分析电磁干扰发射机模型的组成和发射原理,建立基波、谐波、非谐波和互调发射的幅度和频谱(功率谱)模型,并探讨模型中的参数获取方法。结果给出了较为完备的发射机模型,基波调制包络模型分段折线拟合方法,和模型相关参数的测量方法。结论利用上述数学模型,可以进行战场电磁干扰源(发射机)的建模,为战场电磁兼容预测分析与仿真奠定基础。     

“烟塔合一”脱硫技术应用中应注意的问题

以山阴电厂2×300MW机组烟气排放系统采用的烟囱、间冷塔、吸收塔"三塔合一"项目为例,分析了湿法脱硫技术运用在烟塔合一项目中的特点及所需要注意的问题。     

应急救援中紧急冲淋设备的研讨

随着国家经济的飞速发展,减少作业人员在事故发生时所受到的职业危害尤为重要。本文对紧急冲淋设备的技术性能、作用进行了一定探讨与描述,希望对企业正确的配备紧急冲淋设备有所帮助。     

Predicting Bird Species Distributions in Reconstructed Landscapes

Abstract:  Landscape optimization for biodiversity requires prediction of species distributions under alternative revegetation scenarios. We used Bayesian model averaging with logistic regression to predict probabilities of occurrence for 61 species of birds within highly fragmented box–ironbark forests of central Victoria, Australia. We used topographic, edaphic, and climatic variables as predictors so that the models could be applied to areas where vegetation has been cleared but may be replanted. Models were evaluated with newly acquired, independent data collected in large blocks of remnant native vegetation. Successful predictions were obtained for 18 of 45 woodland species (40%). Model averaging produced more accurate predictions than "single best" models. Models were most successful for smaller-bodied species that probably depend on particular vegetation types. Predictions for larger, generalist species, and seasonal migrants were less successful, partly because of changes in species distributions between model building (1995–1997) and validation (2004–2005) surveys. We used validated models to project occurrence probabilities for individual species across a 12,000-km² region, assuming native vegetation was present. These predictions are intended to be used as inputs, along with landscape context and temporal dynamics, into optimization algorithms to prioritize revegetation. Longer-term data sets to accommodate temporal dynamics are needed to improve the predictive accuracy of models.     

精馏过程动态建模与安全控制研究进展

介绍了精馏过程的动态建模与安全控制等方面的研究现状,提出了基于塔板力学模型动态建模与安全分析技术,通过对精馏塔动态特性分析,可准确反映精馏过程的动态变化。根据动态响应规律,建立基于智能调控的先进性控制系统,指导精馏塔、阀门、泵等设备进行变频调节,从而保证精馏塔的稳定运行。     

泵群无线监测系统在石化装置中的应用

介绍了机泵无线监测系统的系统架构、监测方案,并结合具体诊断案例详细说明了其在某千万吨级炼化企业的应用情况。结果表明,该系统能准确评估机泵运行状态,并及时发布报警提示和维护建议,使用该系统事后维修占比由41%降到了15%,预知性维修由不足10%上升到近50%。     

基于备件分析的飞机最经济飞行强度选择

飞机作为航空产品,使用维护成本在全寿命周期费用中占据了相当大的比例。将使用维护成本折算为备件的采购和维修成本,在设计阶段通过基于备件的分析,分类计算在不同飞行强度下各种备件的采购和维修费用,从而确定飞机在满足用户需求的前提下所能执行的最经济的飞行强度。以某型飞机为例,提出了一种最经济飞行强度的计算方法,有助于在设计阶段规划飞机的使用和维护保障。     

Optimal post-warranty maintenance contracts for wind turbines considering availability

ABSTRACT

Outsourcing maintenance is an economical way for wind farm owners to address sophisticated and expensive maintenance operations of wind turbines. This paper proposes three options for the post-warranty maintenance contract of wind turbines from the perspective of service providers. Option 1 involves corrective maintenance only. In option 2, the first preventive maintenance is performed at a certain time point and after that periodic maintenance is carried out. Option 3 initiates with a preventive replacement and performs periodic maintenance subsequently. An availability target is set over the contract period and failing to satisfy the target incurs a penalty from the service provider. The objective is to determine the optimal preventive maintenance programs of option 2 and option 3 that minimize the contract servicing cost. Numerical examples are provided to illustrate the proposed policies. The results show that option 2 and option 3 are more effective than option 1 and their effectiveness grows when warranty and contract coverages increase.