This paper discusses the role which maintenance plays in ecological balance and sustainable development, and the emphasis of the paper is how to achieve the objective to maintain ecological balance and sustainable dev...This paper discusses the role which maintenance plays in ecological balance and sustainable development, and the emphasis of the paper is how to achieve the objective to maintain ecological balance and sustainable development by the product design and maintenance strategies.展开更多
Rockfall risk is often mitigated and managed by employing defensive structures to catch falling blocks(i.e.,passive works).Due to the widely spread nature of rockfall,the presence of such defensive structures is a com...Rockfall risk is often mitigated and managed by employing defensive structures to catch falling blocks(i.e.,passive works).Due to the widely spread nature of rockfall,the presence of such defensive structures is a common sight,especially in mountain areas.The most common passive defensive structures are rockfall flexible barriers,due to their significant flexibility and cost-effectiveness.The protective performance of said structures,though,can be severely reduced by prolonged exposure to weathering agents,vegetation growth,and rockfall impacts:these issues must be addressed by performing maintenance.With a view to optimizing the maintenance procedure,the need arises for a tool capable of providing useful information regarding the condition of existing rockfall barriers,in the simplest yet most complete and comprehensive way possible.The present work provides such a tool,alongside the required instruments for it to function properly.Basically,it consists of a survey spreadsheet to be used to collect raw data based on visual inspection of the barriers,coupled with the methodology to score their conditions and to produce a database with which to manage and plan their maintenance.An application to a suitable case study in the Central Italian Alps,featuring a number of barriers in different conditions,is then presented,and its results are discussed.展开更多
The requirement for reliable electrical energy supply increases continuously because of its vital role in our lives.However,events due to various factors in the power grid can cause energy supply to be interrupted.One...The requirement for reliable electrical energy supply increases continuously because of its vital role in our lives.However,events due to various factors in the power grid can cause energy supply to be interrupted.One of these factors is human error and thus human reliability analysis is a serious element in the industry.The first step is to identify the roots of human error,on which there has been limited research in this area.In this paper,the potential and actual causes of human error in maintenance teams of power transmission system protection are identified and predicted within a framework of human factors analysis and classification system method.Then,human error factors are ranked to help improve human reliability.The proposed method is implemented in the Fars Electricity Maintenance Company.展开更多
The European Standard EN 1504 ＂Products and systems for protection and repair of concrete structures -- Definitions, requirements, quality control and evaluation of conformity＂ can be considered a real milestone for...The European Standard EN 1504 ＂Products and systems for protection and repair of concrete structures -- Definitions, requirements, quality control and evaluation of conformity＂ can be considered a real milestone for the companies involved in the rehabilitation of buildings, bridges, piers, pipelines, and other civil or industrial concrete structures. However in some cases the examination and, even more, the practical application of the proposed guidelines are made difficult by a complicated sub-division in principles and methods, and by a confusing and repetitive layout. The paper deals in particular with the principles and methods for the rehabilitation of concrete damage due to reinforcement corrosion, often strictly connected, anyway, to those adopted in order to rehabilitate the concrete itself. Suggestions are given for a possible future update of the Standard, based on the personal experience of the Authors.展开更多
Aiming at digital relay protection system, a novel hidden failure Markov reliability model is presented for a single main protection and double main protection systems according to hidden failure and protection functi...Aiming at digital relay protection system, a novel hidden failure Markov reliability model is presented for a single main protection and double main protection systems according to hidden failure and protection function under Condition-Based Maintenance (CBM) circumstance and reliability indices such as probability of protection system hidden failure state are calculated. Impacts of different parameters (containing impacts of human errors) to hidden failure state probability and the optimal measures to improve reliability by variable parameter method are also analyzed. It’s demonstrated here that: Compared to a single main protection, double main protection system has an increased hidden failure probability, thus the real good state probability decreases, two main protections’ reliability must be improved at the same time, so configuration of the whole protection system for the component being protected can’t be complicated. Through improving means of on-line self-checking and monitoring system in digital protection system and human reliability, the real application of CBM can decrease hidden failure state probability. Only through this way can we assure that the protection systems work in good state. It has a certain reference value to protection system reliability engineering.展开更多
Objective To explore the routes and factors associated with HIV new infection of heroin addicts who had been attending the methadone maintenance treatment(MMT)program.Methods A 1∶1 nested case-control study was imple...Objective To explore the routes and factors associated with HIV new infection of heroin addicts who had been attending the methadone maintenance treatment(MMT)program.Methods A 1∶1 nested case-control study was implemented with the cases(new HIV infections)and controls(HIV negative)selected from the treatment cohort of China MMT clients.展开更多
文摘This paper discusses the role which maintenance plays in ecological balance and sustainable development, and the emphasis of the paper is how to achieve the objective to maintain ecological balance and sustainable development by the product design and maintenance strategies.
文摘Rockfall risk is often mitigated and managed by employing defensive structures to catch falling blocks(i.e.,passive works).Due to the widely spread nature of rockfall,the presence of such defensive structures is a common sight,especially in mountain areas.The most common passive defensive structures are rockfall flexible barriers,due to their significant flexibility and cost-effectiveness.The protective performance of said structures,though,can be severely reduced by prolonged exposure to weathering agents,vegetation growth,and rockfall impacts:these issues must be addressed by performing maintenance.With a view to optimizing the maintenance procedure,the need arises for a tool capable of providing useful information regarding the condition of existing rockfall barriers,in the simplest yet most complete and comprehensive way possible.The present work provides such a tool,alongside the required instruments for it to function properly.Basically,it consists of a survey spreadsheet to be used to collect raw data based on visual inspection of the barriers,coupled with the methodology to score their conditions and to produce a database with which to manage and plan their maintenance.An application to a suitable case study in the Central Italian Alps,featuring a number of barriers in different conditions,is then presented,and its results are discussed.
文摘The requirement for reliable electrical energy supply increases continuously because of its vital role in our lives.However,events due to various factors in the power grid can cause energy supply to be interrupted.One of these factors is human error and thus human reliability analysis is a serious element in the industry.The first step is to identify the roots of human error,on which there has been limited research in this area.In this paper,the potential and actual causes of human error in maintenance teams of power transmission system protection are identified and predicted within a framework of human factors analysis and classification system method.Then,human error factors are ranked to help improve human reliability.The proposed method is implemented in the Fars Electricity Maintenance Company.
文摘The European Standard EN 1504 ＂Products and systems for protection and repair of concrete structures -- Definitions, requirements, quality control and evaluation of conformity＂ can be considered a real milestone for the companies involved in the rehabilitation of buildings, bridges, piers, pipelines, and other civil or industrial concrete structures. However in some cases the examination and, even more, the practical application of the proposed guidelines are made difficult by a complicated sub-division in principles and methods, and by a confusing and repetitive layout. The paper deals in particular with the principles and methods for the rehabilitation of concrete damage due to reinforcement corrosion, often strictly connected, anyway, to those adopted in order to rehabilitate the concrete itself. Suggestions are given for a possible future update of the Standard, based on the personal experience of the Authors.
文摘Aiming at digital relay protection system, a novel hidden failure Markov reliability model is presented for a single main protection and double main protection systems according to hidden failure and protection function under Condition-Based Maintenance (CBM) circumstance and reliability indices such as probability of protection system hidden failure state are calculated. Impacts of different parameters (containing impacts of human errors) to hidden failure state probability and the optimal measures to improve reliability by variable parameter method are also analyzed. It’s demonstrated here that: Compared to a single main protection, double main protection system has an increased hidden failure probability, thus the real good state probability decreases, two main protections’ reliability must be improved at the same time, so configuration of the whole protection system for the component being protected can’t be complicated. Through improving means of on-line self-checking and monitoring system in digital protection system and human reliability, the real application of CBM can decrease hidden failure state probability. Only through this way can we assure that the protection systems work in good state. It has a certain reference value to protection system reliability engineering.
文摘Objective To explore the routes and factors associated with HIV new infection of heroin addicts who had been attending the methadone maintenance treatment(MMT)program.Methods A 1∶1 nested case-control study was implemented with the cases(new HIV infections)and controls(HIV negative)selected from the treatment cohort of China MMT clients.
