With difficulties in maintaining multicomponent systems of wind turbines and formulating economical and reasonable maintenance strategies,a dynamic opportunistic maintenance strategy of multicomponent systems is appli...With difficulties in maintaining multicomponent systems of wind turbines and formulating economical and reasonable maintenance strategies,a dynamic opportunistic maintenance strategy of multicomponent systems is applied in terms of economic relevance and opportunistic maintenance among various components.A preventive maintenance model based on cost-effectiveness is proposed by incorporating cost-effectiveness analysis into the multicomponent preventive maintenance strategy.The failure rate recovery degree is used to describe the effects of imperfect maintenance and replacement.When the reliability of the component reaches the threshold of preventive or opportunistic maintenance,a reasonable maintenance method is selected on the basis of the cost-effectiveness ratio of the failure rate.A case study is conducted by taking four components of a wind turbine as the research object and comparing them with the opportunistic maintenance model without considering cost-effectiveness.Results show that the total maintenance cost is reduced by 373600 yuan,indicating that the preventive opportunistic maintenance based on cost-effectiveness is more economical and can provide a theoretical basis for formulating a preventive maintenance plan.展开更多
Land use change and its eco-environmental responses are foci in geographical research. As a region with uneven economic development, land use change and eco-environmental responses across Jiangsu Province are relevant...Land use change and its eco-environmental responses are foci in geographical research. As a region with uneven economic development, land use change and eco-environmental responses across Jiangsu Province are relevant to China＇s overall development pattern. The external function of regional land use changes during different stages of economic development. In this study, we proposed a novel classification system based on the dominant function of land use according to ＂production-ecology-life＂, and then analyzed land use change and regional eco-environmental responses from a functional perspective of regional development. The results showed that from 1985 to 2008, land use change features in Jiangsu were that productive land area decreased and eco- logical and living land areas increased. Land use changes in southern Jiangsu were the most dramatic. In southern and central parts of Jiangsu the agricultural production function weakened and urban life service function strengthened; in northern Jiangsu, the mining production function＇s comparative advantage highlighted that the rural life service function was weakening. Ecological environmental quality decreased slightly in Jiangsu and its three regions. The maximum contribution rate to ecological environmental change occurred in southern Jiangsu and the minimum rate was located in the north. Eco-environmental quality deteriorated in southern and central Jiangsu, related to expanding construction land in urban and rural areas. Ecological environmental quality deterioration in northern Jiangsu is probably due to land development and consolidation. The main reason for improvements in regional ecological environments is that agricultural production land was converted to water ecological land across Jiangsu.展开更多
基金The National Key Research and Development Program of China(No.2019YFB1707300).
文摘With difficulties in maintaining multicomponent systems of wind turbines and formulating economical and reasonable maintenance strategies,a dynamic opportunistic maintenance strategy of multicomponent systems is applied in terms of economic relevance and opportunistic maintenance among various components.A preventive maintenance model based on cost-effectiveness is proposed by incorporating cost-effectiveness analysis into the multicomponent preventive maintenance strategy.The failure rate recovery degree is used to describe the effects of imperfect maintenance and replacement.When the reliability of the component reaches the threshold of preventive or opportunistic maintenance,a reasonable maintenance method is selected on the basis of the cost-effectiveness ratio of the failure rate.A case study is conducted by taking four components of a wind turbine as the research object and comparing them with the opportunistic maintenance model without considering cost-effectiveness.Results show that the total maintenance cost is reduced by 373600 yuan,indicating that the preventive opportunistic maintenance based on cost-effectiveness is more economical and can provide a theoretical basis for formulating a preventive maintenance plan.
基金National Natural Science Foundation of China(71503117,41301651)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Land use change and its eco-environmental responses are foci in geographical research. As a region with uneven economic development, land use change and eco-environmental responses across Jiangsu Province are relevant to China＇s overall development pattern. The external function of regional land use changes during different stages of economic development. In this study, we proposed a novel classification system based on the dominant function of land use according to ＂production-ecology-life＂, and then analyzed land use change and regional eco-environmental responses from a functional perspective of regional development. The results showed that from 1985 to 2008, land use change features in Jiangsu were that productive land area decreased and eco- logical and living land areas increased. Land use changes in southern Jiangsu were the most dramatic. In southern and central parts of Jiangsu the agricultural production function weakened and urban life service function strengthened; in northern Jiangsu, the mining production function＇s comparative advantage highlighted that the rural life service function was weakening. Ecological environmental quality decreased slightly in Jiangsu and its three regions. The maximum contribution rate to ecological environmental change occurred in southern Jiangsu and the minimum rate was located in the north. Eco-environmental quality deteriorated in southern and central Jiangsu, related to expanding construction land in urban and rural areas. Ecological environmental quality deterioration in northern Jiangsu is probably due to land development and consolidation. The main reason for improvements in regional ecological environments is that agricultural production land was converted to water ecological land across Jiangsu.
