Research and Application of Maintenance Decision Method of Complex Equipment in Nuclear Power Plant

The determination of maintenance mode of complex equipment in nuclear power plant is an essential work for reliability analysis and maintenance decision. Currently, the main decision method of maintenance mode is reliability centered maintenance( RCM) logic decision-making process, but the process is a qualitative analysis process. Based on a comprehensive analysis of factors affecting equipment reliability and maintenance work, it adopts a fuzzy synthesis decision method to establish a maintenance decision model,which uses the maximum subordination principle and expert assessment method to determine the maintenance mode of complex equipment. Combined with a concrete example of generators in nuclear power plant,a description of maintenance decision method was proposed in the application of complex equipment. The research shows that the method is feasible and reliable.

Procurement Method Selection for Building Maintenance Projects: The Case of Malaysian Public Universities

The purpose of this paper is to implement and validate a decision making framework for building maintenance projects. The growing importance of maintenance sector not only in Malaysia but al- so increasingly globalized, the difficulty in selecting an appropriate procurement method and lack of research in this area provide an impetus for this research. There were 19 procurement selection criteria identified. In addition, there were 4 types of procurements methods which include outsourcing by specialist term contract, outsourcing by tendered schedule term contract, out- sourcing by repair and maintenance contract and outsourcing by measured term contract identified to be the most popular procurement methods adapted by public universities currently and at the same time were considered most important. The decision making framework was developed based on AHP technique and principles. Expert Choice Software was employed as development tool where the criteria and alternatives were integrated into the framework. Finally, structured interview was conducted to validate the framework developed. The validation process was carried out through structured interview with selected public university.

Smart Society and Artificial Intelligence:Big Data Scheduling and the Global Standard Method Applied to Smart Maintenance

The implementation of artificial intelligence(AI)in a smart society,in which the analysis of human habits is mandatory,requires automated data scheduling and analysis using smart applications,a smart infrastructure,smart systems,and a smart network.In this context,which is characterized by a large gap between training and operative processes,a dedicated method is required to manage and extract the massive amount of data and the related information mining.The method presented in this work aims to reduce this gap with near-zero-failure advanced diagnostics(AD)for smart management,which is exploitable in any context of Society 5.0,thus reducing the risk factors at all management levels and ensuring quality and sustainability.We have also developed innovative applications for a humancentered management system to support scheduling in the maintenance of operative processes,for reducing training costs,for improving production yield,and for creating a human–machine cyberspace for smart infrastructure design.The results obtained in 12 international companies demonstrate a possible global standardization of operative processes,leading to the design of a near-zero-failure intelligent system that is able to learn and upgrade itself.Our new method provides guidance for selecting the new generation of intelligent manufacturing and smart systems in order to optimize human–machine interactions,with the related smart maintenance and education.

Ship System Maintenance Strategy Selection Based on DELPHI-AHP-TOPSIS Methodology

Maintenance decision problems generally involve multiple criteria which apparently are best addressed using Multi-Criteria Decision Making (MCDM) tools. This paper describes the use of a hybrid MCDM technique in prioritizing maintenance strategy for ship systems. The Hybrid MCDM technique combines Delphi method, AHP and TOPSIS methods. While the Delphi method and AHP are applied in screening of decision criteria and decision criteria weights determination respectively, the TOPSIS method is used in the ranking of alternative maintenance strategies. Five alternative maintenance strategies which include corrected maintenance, scheduled overhaul, scheduled replacement, continuous on-condition task and scheduled on-condition task are considered and the optimum maintenance strategy is selected based on twelve critical maintenance decision criteria. To demonstrate the suitability of the approach a case study of sea water pump of the central cooling system of a marine diesel engine is used.

Selection of Water Transmission Method and Analysis of Pipe Network Zoning in Municipal Water Supply and Drainage Design

With the acceleration of urbanization,the demand for water supply and drainage pipe networks has increased significantly.In the planning of urban construction,it is necessary to optimize the design of the water supply and drainage system pipe network to effectively save energy while providing residents with more accessible water resources.Therefore,the municipal water supply and drainage system and the water transmission methods should be designed according to the geographical conditions of the city.In this paper,we mainly analyze the design of municipal water supply and drainage systems and the selection of water transmission methods.Besides,the optimization of the water supply and drainage network zoning process and pipe network maintenance is also discussed,so as to provide a reference for municipal water supply and drainage work.

Analysis of the Improvement Methods for Equipment Maintenance Support

According to military requirement, and based on the problems of equipmentmaintenance support methods in high-tech battles, each element supporting equipment maintenance isanalyzed, and the methods for improving equipment maintenance are proposed.

Suggestion of Maintenance Criteria for Electric Railroad Facilities Based on Fuzzy TOPSIS

This paper is on the suggestion of maintenance items for electric railway facility systems.With the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility systems are also increasing,but the railroad electrical facility system in Korea is rapidly aging.To solve this problem,various methodologies are applied to ensure operational reliability and stability for railroad electrical facility systems,but there is a lack of detailed evaluation criteria for railroad electrical facility system maintenance.Also,maintenance items must be selected in a scientific and systematic method.Therefore,railroad electrical facility systems are selected for study.Design StructureMatrix(DSM)is utilized to establish considerations tailored to the maintenance characteristics,and the Fuzzy-TOPSIS methodology is utilized for determining the maintenance detail evaluation item baseline weights,a multi-criteria decision-making problem.Studies show that degradation,insulation items have the highest weight of 14.63%,and capacity items have the lowest weight of 5.34%.The results of this may be contributed to the underlying research in carrying out maintenance activities to ensure the reliability and safety of railroad electrical facility systems.

Multiobjective maintenance optimization of the continuously monitored deterioration system

With the development of the monitoring technology,it is more and more common that the system is continuously monitored.Therefore,the research on the maintenance optimization of the continuously monitored deterioration system is important.The deterioration process of the discussed system is described by a Gamma process.The predictive maintenance is considered to be imperfect and formulated.The expected interval of two continuous preventive maintenances is derived.Then,the maintenance optimization model of the continuously monitored deterioration system is presented.In the model,the minimization of the expected operational cost per unit time and the maximization of the system availability are the optimization objectives.The improved ideal point method with the normalized objective functions is employed to solve the proposed model.The validity and sensitivity of the proposed multiobjective maintenance optimization model are analyzed by a numerical example.

Comprehensive Evaluation of Service Level of Transmission Equipment Maintenance Plan

With the interconnection of power grid, the increase of coupling, the rapid development of new energy, the inter-provincial cross-regional power market transactions, it is an important way that the integrated presentation of grid outage maintenance plan to ensure the safety of power grid, ensure the normal operation of the market, improve the efficiency of maintenance and reduce the cost of maintenance. Maintenance plan is in the annual, monthly, daily and other dimensions of time rolling management process. Maintenance planning level assessment can improve the service level of maintenance plan compilers and the efficiency of maintenance, it also achieves fine management of the power grid. This paper presents an evaluation model of maintenance business level, which is a comprehensive evaluation model of multi-index. The indexes in the model are based on the maintenance service level measurement, the efficiency of the maintenance plan, the emergencies of the maintenance plan and others Impact factors and other aspects of multi-angle assessment. The validity and correctness of the evaluation system and the comprehensive evaluation method are verified by the analysis of practical examples.

Modeling and Application of Maintenance Bill of Materials for Complex Equipment

In the industrial engineering, the maintenance and logistics support process is one of the key factors for the performance of equipment. Bill of materials( BOM) describes all the components in product and internal hierarchal relationships as a structured tree.In order to gain all required maintenance information for complex equipment which is complex,the modeling and the application of maintenance BOM are introduced in this paper. Because of the simple structure and the wide function,IDEF0 is presented to build the model of maintenance BOM. The modeling approach can gather the maintenance information conveniently based on other BOMs,and applications of maintenance BOM are widely,particularly,in maintenance and inventory management.

基于DEMATEL-ISM方法的水电站机组检修作业安全事故致因链分析

针对水电站机组检修作业种类和危险因素多、安全事故频发等问题,通过文献挖掘与专家访谈方式,对水电站机组检修作业安全影响因素类别进行了划分。基于DEMATEL-ISM方法,构建了安全事故致因多层次递阶ISM模型来确定事故致因因素层级,通过剖析事故致因因素的中心度和权重,挖掘关键致因因素和推求事故致因链的路径权重,厘定关键致因链。采用该模型对某水电站致因链进行了分析,结果表明,安全检查不到位为关键致因因素,“安全检查不到位→违规作业→设备的问题→粉尘、油漆等有害物质”为关键致因链。

费曼式学习法在低年资护士儿童PICC维护培训中的应用

目的:探讨费曼式学习法在低年资护士儿童经外周静脉置入中心静脉导管(PICC)维护培训中的应用。方法:2022年3月—12月选取无锡市儿童医院80名低年资护士参与儿童PICC导管维护培训,采用随机数字表法将其分为观察组及对照组,每组40人。对照组行规范性培训,观察组应用费曼式学习法,比较两组护士规范化培训参与率、PICC置管知识及技能考核评分、护士自主学习能力及PICC知信行评分。结果:观察组护士第4次~第6次培训参与率明显高于对照组(P<0.05);观察组培训结束时PICC置管知识评分、技能考核评分、护士自主学习能力评分及PICC知信行评分高于对照组(P<0.05)。结论:费曼式学习法可提升低年资护士参与儿童PICC维护培训参与率,改善低年资护士自主学习能力及PICC维护知信行水平,有助于护士PICC维护知识及维护技能的提升。

热障涂层在航空发动机涡轮叶片上的应用、失效与维护

航空发动机涡轮叶片热障涂层对延长涡轮叶片的使用寿命具有至关重要的作用。首先概述了航空发动机热障涂层的重要性,其次归纳了航空发动机涡轮叶片热障涂层的制备技术及应用特点,主要对大气等离子、电子束物理气相沉积、等离子喷涂-物理气相沉积等3种热障涂层进行了论述。在此基础上,重点阐述了热障涂层在航空发动机涡轮叶片中的典型失效形式,包括高温氧化失效、热腐蚀失效及颗粒物冲击,对以上失效形式的失效机理进行了重点论述。最后结合发动机状态监控及涡轮叶片孔探技术,对涡轮叶片热障涂层的常见典型失效给出了工程案例分析与建议。

基于冲突划分的位图多版本增量创建算法

根据位图操作间的冲突关系对待执行操作在位图版本中的冲突像素区域进行冲突划分,将属于相同冲突的像素区域独立成一个冲突像素集。使用多版本方法解决冲突,即对于每一个冲突像素集,将位图版本增量复制后,分别在冲突像素集中所包含的像素区域执行冲突操作的操作效果得到增量创建的位图版本,以达到一致性维护的目的。最后对方法的正确性和有效性进行了证明。在自定义的数据集上进行实验,结果表明,所提出的CDBMVIC算法产生的位图版本数量和冗余位图版本数量都比BTMVIC算法少。

基于层次分析与改进模糊评价的水电机组检修效果综合评价

为综合评价水电机组检修效果,考虑水电机组工况多变的特点,提出了基于层次分析法(AHP)与改进模糊评价法的水电机组检修效果综合评价模型,首先依据实际电站建立了水电机组检修效果综合评价指标体系;然后,结合AHP主观权重法和Critic方法构建了权重综合计算模型,获取各层指标综合权重;接着研究了水电机组设备检修效果评价指标量化方法,将量化的水电机组设备检修效果评价指标应用于模糊评价模型中,求解各指标模糊评判矩阵,给出水电机组检修前后综合得分,实现水电机组检修效果定量评估;最后以实际电站机组为例,利用多工况下的监测数据,验证了所提方法的有效性。

便携式在役锚索预应力检测设备研制及应用

现有的锚索预应力检测设备要求锚索外露段长度>70 cm,不适应于运维期的在役锚索检测,且质量大都在150 kg以上,对于高陡边坡锚索检测显得笨重。为此研制了HRAD-300型便携式在役锚索预应力智能检测仪,可适用于钢绞线外露长度>7 cm的在役锚索预应力检测。检测仪位移量程200 mm,测量误差0.01 mm;测力量程300 kN,测量误差±1%FS,单件质量<15 kg,总质量<40 kg。基于反拉法原理及检测曲线形态,提出锚下有效预应力算法,并编制了相关软件。室内试验表明,检测曲线形态多为拐点不明显型,计算值与原始锁定值基本一致。使用该设备对邛崃市天台山景区凤凰岩不稳定斜坡锚固工程进行检测,结果表明,现场锚索检测曲线多为拐点明显型,具有明显的突变点及陡降;锚索运行状态良好,持续发挥功效,2号锚索预应力损失较为明显,可以采取补偿张拉方式;同一锚索的不同钢绞线存在受力不均的情况。便携式在役锚索预应力检测仪智能、轻便,可为锚固工程健康评价提供数据支撑。

基于Wiener退化过程的动车组部件状态-机会维修模型分析与研究

针对动车组多部件存在运行维修成本高、欠维修或过维修的现象以及故障影响范围大等问题,提出一种基于Wiener退化过程的部件状态-机会维修优化模型。该模型利用Wiener过程描述部件在运行过程中的劣化程度,通过基于指数分布的随机几何过程反映不完全维修后部件的劣化损伤,同时利用定期检测获取部件的实际劣化值。从随机过程和拓扑的角度,分析不同类型维修策略之间的区别与联系。结合单部件状态维修优化策略,求得各部件的最优状态阈值和维修检测周期。引入机会阈值与状态阈值的比值,结合部件退化过程与状态阈值、机会阈值之间的关系,推导部件状态、机会维修次数期望值的数学表达式,建立状态-机会维修策略模型,采用蒙特卡洛算法进行模拟,确定各部件的最佳机会阈值,达到优化维修费用率的目标。以某型号动车组牵引供电系统为例,通过仿真验证,表明采取状态-机会维修模型,可以有效减少停机次数,降低维修费用率。

我国农村生活污水与农田退水面源氮磷污染生态净化技术现状与研究进展

当前,我国农村生活污水与农田退水面源氮磷污染尚未得到有效治理,解决此类污染的代表措施——“生态净化技术”的发展广受关注。本文从技术发展、技术标准、技术体系三个角度切入,对农村生活污水与农田退水氮磷污染生态净化技术进行梳理分析。技术发展从分析和介绍当前热门生态净化技术的研究进展开始,通过调研整理这些技术在我国的推广和应用,梳理其在我国不同区域的发展特征,归纳出当前生态净化技术应用所面临的困难。当前相关部门对生态净化工程的监管仅关注出水水质的达标率,缺乏有效的后期维护及意见调查反馈。在技术标准方面,本文梳理了关于已发布实施的生态净化工程的的系列标准,认为应引入综合效益评价方法,以完善我国生态净化工程的评价体系。在技术体系方面,以生态净化技术的拦截性和修复性为依据对单一技术进行分类,并分别针对农村生活污水、农田退水提出了对应的技术联用体系。

超大深基坑工程基坑围护体系设计研究

文章以某项目深基坑支护结构选型为例,结合工程地质水文条件以及施工进度和成本等综合因素,通过分析基坑主要特点、基坑需主要解决问题,对基坑支护总体方案进行比选,在确保基坑本身及周边环境安全的前提下,分别从整体顺作法、分区顺作法、逆作法三个方面对工期及费用进行综合分析,确定最佳围护体系,确保基坑施工稳定安全。