WorldWideScience

Sample records for condition based maintenance

  1. On condition based maintenance policy

    Directory of Open Access Journals (Sweden)

    Jong-Ho Shin

    2015-04-01

    Full Text Available In the case of a high-valuable asset, the Operation and Maintenance (O&M phase requires heavy charges and more efforts than the installation (construction phase, because it has long usage life and any accident of an asset during this period causes catastrophic damage to an industry. Recently, with the advent of emerging Information Communication Technologies (ICTs, we can get the visibility of asset status information during its usage period. It gives us new challenging issues for improving the efficiency of asset operations. One issue is to implement the Condition-Based Maintenance (CBM approach that makes a diagnosis of the asset status based on wire or wireless monitored data, predicts the assets abnormality, and executes suitable maintenance actions such as repair and replacement before serious problems happen. In this study, we have addressed several aspects of CBM approach: definition, related international standards, procedure, and techniques with the introduction of some relevant case studies that we have carried out.

  2. Condition based maintenance in the context of opportunistic maintenance

    NARCIS (Netherlands)

    Koochaki, Javid; Bokhorst, Jos A. C.; Wortmann, Hans; Klingenberg, Warse

    2012-01-01

    Condition based maintenance (CBM) uses the operating condition of a component to predict a failure event. Compared to age based replacement (ABR), CBM usually results in higher availability and lower maintenance costs, since it tries to prevent unplanned downtime and avoid unnecessary preventive

  3. Collaborative learning in condition based maintenance

    NARCIS (Netherlands)

    Koochaki, J.; Ao, SI; Gelman, L; Hukins, DWL; Hunter, A; Korsunsky, AM

    2009-01-01

    In recent years, the importance of reliable and consistent production equipments has increased. As a result, companies are shifting their maintenance policy from preventive maintenance towards Condition Based Maintenance (CBM). Despite the growing trend in this area and success stories of CBM

  4. Advantages of condition-based maintenance approach

    International Nuclear Information System (INIS)

    Bareiss, J.; Roos, E.; Jovanovic, A.; Perunicic, M.; Balos, D.

    2004-01-01

    Pilot applications in EnBW steam boiler components and high-pressure pipe systems in the context of the European research project RIMAP (''Risk Based Inspection and Maintenance Procedures for European Industry'') showed that application of a risk-based maintenance strategy (e.g. RIMAP) will make the decision process more transparent and enable better condition-oriented maintenance. With regard to life management of the systems (availability, product quality), this appears to be more important than than the aspect of cost reduction in the maintenance sector, although the latter may not be unwelcome. (orig.) [de

  5. Condition based maintenance pilot projects at Pickering ND

    International Nuclear Information System (INIS)

    Zemdegs, R.T.

    1995-01-01

    Ontario Hydro has recognized that the approaches to maintenance have undergone significant changes to the past decades. The traditional break down maintenance approach has been replaced by preventative maintenance and more recently, by condition based maintenance. The nuclear plants of Ontario Hydro have evaluated on a number of alternative programs to improve their maintenance effectiveness and to reduce costs, including Reliability Centred Maintenance (RCM), call-up review, component-based PM programs, analysis of failure history and so on. Pickering ND (nuclear division) and Ontario Hydro's Nuclear Technologies Services Division, have embarked on a Condition Based Maintenance pilot project to address the above issues as a breakthrough solution for smarter maintenance. The Condition Based Maintenance pilot project will demonstrate an end-to-end process utilizing a Reliability Centred Maintenance structured approach to re-engineer and redefine the existing maintenance programs. The project emphasizes on-condition maintenance where justified, and utilizes an information management tool to provide the required records keeping and analysis infrastructure. This paper briefly describes the planned maintenance model at Pickering ND used to guide the CBM pilot, and an overview of the methodology used to develop on-condition equipment indicators as part of a re-engineered maintenance plan

  6. Application of condition based maintenance to nuclear power plants

    International Nuclear Information System (INIS)

    Sonoda, Yukio; Nakano, Tomohito; Shimizu, Shunichi; Iida, Jun; Atomura, Masakazu; Abe, Masahiro

    2002-01-01

    Device Karte management system which supports application of condition based maintenance to nuclear power plants has been developed. The purpose of this system is to support maintenance personnel in device inspection scheduling based on operating condition monitoring and maintenance histories. There are four functions: field database, degradation estimation, inspection time decision and maintenance planning. The authors have been applying this system to dozens of devices of Onagawa Nuclear Power Station Unit No. 1 for one year. This paper represents the system concept and its application experiences. (author)

  7. Discounted cost model for condition-based maintenance optimization

    International Nuclear Information System (INIS)

    Weide, J.A.M. van der; Pandey, M.D.; Noortwijk, J.M. van

    2010-01-01

    This paper presents methods to evaluate the reliability and optimize the maintenance of engineering systems that are damaged by shocks or transients arriving randomly in time and overall degradation is modeled as a cumulative stochastic point process. The paper presents a conceptually clear and comprehensive derivation of formulas for computing the discounted cost associated with a maintenance policy combining both condition-based and age-based criteria for preventive maintenance. The proposed discounted cost model provides a more realistic basis for optimizing the maintenance policies than those based on the asymptotic, non-discounted cost rate criterion.

  8. Knowledge Management for Large Scale Condition Based Maintenance

    Data.gov (United States)

    National Aeronautics and Space Administration — This presentation will review the use of knowledge management in the development and support of Condition Based Maintenance (CBM) systems for complex systems with...

  9. A proactive condition-based maintenance strategy with both perfect and imperfect maintenance actions

    International Nuclear Information System (INIS)

    Do, Phuc; Voisin, Alexandre; Levrat, Eric; Iung, Benoit

    2015-01-01

    This paper deals with a proactive condition-based maintenance (CBM) considering both perfect and imperfect maintenance actions for a deteriorating system. Perfect maintenance actions restore completely the system to the ‘as good as new’ state. Their related cost are however often high. The first objective of the paper is to investigate the impacts of imperfect maintenance actions. In fact, both positive and negative impacts are considered. Positive impact means that the imperfect maintenance cost is usually low. Negative impact implies that (i) the imperfect maintenance restores a system to a state between good-as-new and bad-as-old and (ii) each imperfect preventive action may accelerate the speed of the system's deterioration process. The second objective of the paper is to propose an adaptive maintenance policy which can help to select optimally maintenance actions (perfect or imperfect actions), if needed, at each inspection time. Moreover, the time interval between two successive inspection points is determined according to a remaining useful life (RUL) based-inspection policy. To illustrate the use of the proposed maintenance policy, a numerical example finally is introduced. - Highlights: • A new imperfect maintenance model for deterioration system is proposed. • Both positive and negative impacts of an imperfect maintenance action are investigated. • An adaptive condition-based maintenance policy is introduced. • The optimal number of useful imperfect maintenance actions for each life cycle is optimally provided

  10. A condition-based maintenance policy for stochastically deteriorating systems

    International Nuclear Information System (INIS)

    Grall, A.; Berenguer, C.; Dieulle, L.

    2002-01-01

    We focus on the analytical modeling of a condition-based inspection/replacement policy for a stochastically and continuously deteriorating single-unit system. We consider both the replacement threshold and the inspection schedule as decision variables for this maintenance problem and we propose to implement the maintenance policy using a multi-level control-limit rule. In order to assess the performance of the proposed maintenance policy and to minimize the long run expected maintenance cost per unit time, a mathematical model for the maintained system cost is derived, supported by the existence of a stationary law for the maintained system state. Numerical experiments illustrate the performance of the proposed policy and confirm that the maintenance cost rate on an infinite horizon can be minimized by a joint optimization of the maintenance structure thresholds, or equivalently by a joint optimization of a system replacement threshold and the aperiodic inspection schedule

  11. Development of electromagnetic induction diagnostics technology for condition based maintenance

    International Nuclear Information System (INIS)

    Mawatari, Shingo; Oeda, Kaoru; Yatogi, Hideo; Fukuchi, Taira; Ueno, Tadashi

    2008-01-01

    In ROKKASHO Reprocessing Plant (below, called 'RRP'), we have applied Condition Based Maintenance to rotating equipment with vibration diagnostics technology. However, a few rotating equipment are difficult to diagnose definitely, because have structural problems which exercise vibrational noise to peripheral and be impossible to install vibratory sensor. Electromagnetic induction diagnostics technology which measure magnetic fields to eddy current which is induced to rotary through static magnetic field, diagnose deterioration behavior such as abrasion and crack. As a result, it has possibilities to clear above problems. Therefore, we started our basic researches with this technology for Condition Based Maintenance. In this paper, it introduces basic data about 'Non-seal pump' that have installed in RRP. As a result, this technology is a possibility that be able to detect Condition Based Maintenance. (author)

  12. An Intelligent Fleet Condition-Based Maintenance Decision Making Method Based on Multi-Agent

    OpenAIRE

    Bo Sun; Qiang Feng; Songjie Li

    2012-01-01

    According to the demand for condition-based maintenance online decision making among a mission oriented fleet, an intelligent maintenance decision making method based on Multi-agent and heuristic rules is proposed. The process of condition-based maintenance within an aircraft fleet (each containing one or more Line Replaceable Modules) based on multiple maintenance thresholds is analyzed. Then the process is abstracted into a Multi-Agent Model, a 2-layer model structure containing host negoti...

  13. Corrosion Sensor Development for Condition-Based Maintenance of Aircraft

    Directory of Open Access Journals (Sweden)

    Gino Rinaldi

    2012-01-01

    Full Text Available Aircraft routinely operate in atmospheric environments that, over time, will impact their structural integrity. Material protection and selection schemes notwithstanding, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures. For aircraft operators, this becomes an important safety matter as corrosion found in a given aircraft must be assumed to be present in all of that type of aircraft. This safety protocol and its associated unscheduled maintenance requirement drive up the operational costs of the fleet and limit the availability of the aircraft. Hence, there is an opportunity at present for developing novel sensing technologies and schemes to aid in shifting time-based maintenance schedules towards condition-based maintenance procedures. In this work, part of the ongoing development of a multiparameter integrated corrosion sensor is presented. It consists of carbon nanotube/polyaniline polymer sensors and commercial-off-the-shelf sensors. It is being developed primarily for monitoring environmental and material factors for the purpose of providing a means to more accurately assess the structural integrity of aerospace aluminium alloys through fusion of multiparameter sensor data. Preliminary experimental test results are presented for chloride ion concentration, hydrogen gas evolution, humidity variations, and material degradation.

  14. Structural health monitoring methodology for aircraft condition-based maintenance

    Science.gov (United States)

    Saniger, Jordi; Reithler, Livier; Guedra-Degeorges, Didier; Takeda, Nobuo; Dupuis, Jean Pierre

    2001-06-01

    Reducing maintenance costs while keeping a constant level of safety is a major issue for Air Forces and airlines. The long term perspective is to implement condition based maintenance to guarantee a constant safety level while decreasing maintenance costs. On this purpose, the development of a generalized Structural Health Monitoring System (SHMS) is needed. The objective of such a system is to localize the damages and to assess their severity, with enough accuracy to allow low cost corrective actions. The present paper describes a SHMS based on acoustic emission technology. This choice was driven by its reliability and wide use in the aerospace industry. The described SHMS uses a new learning methodology which relies on the generation of artificial acoustic emission events on the structure and an acoustic emission sensor network. The calibrated acoustic emission events picked up by the sensors constitute the knowledge set that the system relies on. With this methodology, the anisotropy of composite structures is taken into account, thus avoiding the major cause of errors of classical localization methods. Moreover, it is adaptive to different structures as it does not rely on any particular model but on measured data. The acquired data is processed and the event's location and corrected amplitude are computed. The methodology has been demonstrated and experimental tests on elementary samples presented a degree of accuracy of 1cm.

  15. Clustering condition-based maintenance for a multi-unit system with aperiodic inspections

    NARCIS (Netherlands)

    Olde Keizer, Minou C.A.; Teunter, Ruud H.; Podofillini, Luca; Sudret, Bruno; Stojadinović, Božidar; Zio, Enrico; Kröger, Wolfgang

    2015-01-01

    Condition-Based Maintenance (CBM) is a predictive maintenance strategy, which bases the maintenance scheduling on condition measurements of the components. In this paper, we continue work on the CBM optimization approach proposed by Castanier, B., A. Grall & C. Bérenguer (2005). A condition-based

  16. Influencing factors for condition-based maintenance in railway tracks using knowledge-based approach

    NARCIS (Netherlands)

    Jamshidi, A.; Hajizadeh, S.; Naeimi, M.; Nunez Vicencio, Alfredo; Li, Z.

    2017-01-01

    In this paper, we present a condition-based maintenance decision method using
    knowledge-based approach for rail surface defects. A railway track may contain a considerable number of surface defects which influence track maintenance decisions. The proposed method is based on two sets of

  17. A basic condition-based maintenance strategy for air-cooled turbine generators

    International Nuclear Information System (INIS)

    Laird, T.; Griffith, G.; Hoof, M.

    2005-01-01

    This paper discusses the methods of using condition-based maintenance (CBM) for turbine generators. Even though it is focused on the maintenance strategy for air-cooled generators, all types of power producers can realize benefits from a better maintenance strategy at lower costs. A reliable assessment of the actual unit condition requires detailed knowledge of the unit design, operational weaknesses, cost of maintenance and operational capabilities. (author)

  18. Condition Based Maintenance of Space Exploration Vehicles Using Structural Health Monitoring, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Acellent Technologies proposes to develop an autonomous and automated diagnostic system for condition based maintenance (CBM) of safety critical structures for space...

  19. Condition-based maintenance at both scheduled and unscheduled opportunities

    NARCIS (Netherlands)

    Kalosi, S.; Kapodistria, S.; Resing, J.A.C.

    2016-01-01

    Motivated by original equipment manufacturer (OEM) service and maintenance practices we consider a single component subject to replacements at failure instances and two types of preventive maintenance opportunities: scheduled, which occur due to periodic system reviews of the equipment, and

  20. An Intelligent Fleet Condition-Based Maintenance Decision Making Method Based on Multi-Agent

    Directory of Open Access Journals (Sweden)

    Bo Sun

    2012-01-01

    Full Text Available According to the demand for condition-based maintenance online decision making among a mission oriented fleet, an intelligent maintenance decision making method based on Multi-agent and heuristic rules is proposed. The process of condition-based maintenance within an aircraft fleet (each containing one or more Line Replaceable Modules based on multiple maintenance thresholds is analyzed. Then the process is abstracted into a Multi-Agent Model, a 2-layer model structure containing host negotiation and independent negotiation is established, and the heuristic rules applied to global and local maintenance decision making is proposed. Based on Contract Net Protocol and the heuristic rules, the maintenance decision making algorithm is put forward. Finally, a fleet consisting of 10 aircrafts on a 3-wave continuous mission is illustrated to verify this method. Simulation results indicate that this method can improve the availability of the fleet, meet mission demands, rationalize the utilization of support resources and provide support for online maintenance decision making among a mission oriented fleet.

  1. The role of knowledge sharing and transactive memory system on condition based maintenance policy

    NARCIS (Netherlands)

    Koochaki, J.; Bouwhuis, I. M.

    2008-01-01

    Today, Condition Based Maintenance (CBM) has reached a sophisticated level in industry and the advantages of predictive maintenance are accepted globally. However, although lots of effort has been put into improving methods and techniques in CBM, most of predictive maintenance programs fail to

  2. A condition-based maintenance policy for multi-component systems with a high maintenance setup cost

    NARCIS (Netherlands)

    Zhu, Q.; Peng, H.; Houtum, van G.J.J.A.N.

    2015-01-01

    Condition-based maintenance (CBM) is becoming increasingly important due to the development of advanced sensor and information technology, which facilitates the remote collection of condition data. We propose a new CBM policy for multi-component systems with continuous stochastic deteriorations. To

  3. A condition-based maintenance policy for multi-component systems with a high maintenance setup cost

    NARCIS (Netherlands)

    Zhu, Q.; Peng, H.; Houtum, van G.J.J.A.N.

    2012-01-01

    Condition-based maintenance (CBM) is becoming increasingly important due to the development of advanced sensor and ICT technology, so that the condition data can be collected remotely. We propose a new CBM policy for multi-component systems with continuous stochastic deteriorations. To reduce the

  4. A novel integrated condition-based maintenance and stochastic flexible job shop scheduling problem

    DEFF Research Database (Denmark)

    Rahmati, Seyed Habib A.; Ahmadi, Abbas; Govindan, Kannan

    2018-01-01

    the level of the system optimization. By means of this equipment, managers can benefit from a condition-based maintenance (CBM) for monitoring and managing their system. The chief aim of the paper is to develop a stochastic maintenance problem based on CBM activities engaged with a complex applied......Integrated consideration of production planning and maintenance processes is a real world assumption. Specifically, by improving the monitoring equipment such as various sensors or product-embedded information devices in recent years, joint assessment of these processes is inevitable for enhancing...... production problem called flexible job shop scheduling problem (FJSP). This integrated problem considers two maintenance scenarios in terms of corrective maintenance (CM) and preventive maintenance (PM). The activation of scenario is done by monitoring the degradation condition of the system and comparing...

  5. Condition-based maintenance for complex systems : Coordinating maintenance and logistics planning for the process industries

    NARCIS (Netherlands)

    Olde Keizer, Minou Catharina Anselma

    2016-01-01

    Maintenance planning in the process industries is extremely complex for various reasons. Plants often run nonstop, allowing little time for performing preventive maintenance. Failures should be prevented, however, as they can lead to system downtime and high losses of revenue. Corrective maintenance

  6. Open system architecture for condition based maintenance applied to a hydroelectric power plant

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, E.J.; Alvares, A.J. [University of Brasilia (UnB), DF (Brazil). Mechanical and Mechatronic Dept.], Emails: eamaya@unb.br, alvares@AlvaresTech.com; Gudwin, R.R. [State University of Campinas (UNICAMP), SP (Brazil). Computer Engineering and Industrial Automation Dept.], E-mail: gudwin@dca.fee.unicamp.br

    2009-07-01

    The hydroelectric power plant of Balbina is implementing a condition based maintenance system applying an open, modular and scalable integrated architecture to provide comprehensive solutions and support to the end users like operational and maintenance team. The system called SIMPREBAL (Predictive Maintenance System of Balbina) is advocate of open standards, in particular through collaborative research programmers. In the developing is clearly understands the need for both, industry standards and a simple to use software development tool chain, supporting the development of complex condition based maintenance systems with multiple partners. The Open System Architecture for Condition Based Maintenance (OSA-CBM) is a standard that consider seven hierarchic layers that represent a logic transition or performed data flow from the data acquisition layer, through the intermediates layers as signal processing, condition monitor, health assessment, prognostics and decision support, to arrive to the presentation layer. SIMPREBAL is being implementing as an OSA-CBM software framework and tool set that allows the creation of truly integrated, comprehensive maintenance solutions through the internet. This paper identifies specific benefits of the application of the OSA-CBM in comprehensive solutions of condition based maintenance for a hydroelectric power plant. (author)

  7. Maintenance cost optimization in condition based maintenance: a case study for critical facilities

    OpenAIRE

    Filippo De Carlo; Maria Antonietta Arleo

    2013-01-01

    The increasing availability required to industrial plants and the limited budget often existing to assure it, require a careful formulation of maintenance optimization models. This need is primary for process plants, for which minimization of stops and maximization of their availability, are essential for ensuring targeted production and, therefore, profitability. In this context, the choice of the maintenance strategy is hence fundamental, depending on the system features and then on the eff...

  8. Bayesian based Diagnostic Model for Condition based Maintenance of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Asgarpour, Masoud; Sørensen, John Dalsgaard

    2018-01-01

    Operation and maintenance costs are a major contributor to the Levelized Cost of Energy for electricity produced by offshore wind and can be significantly reduced if existing corrective actions are performed as efficiently as possible and if future corrective actions are avoided by performing...... sufficient preventive actions. This paper presents an applied and generic diagnostic model for fault detection and condition based maintenance of offshore wind components. The diagnostic model is based on two probabilistic matrices; first, a confidence matrix, representing the probability of detection using...... for a wind turbine component based on vibration, temperature, and oil particle fault detection methods. The last part of the paper will have a discussion of the case study results and present conclusions....

  9. Joint optimization of condition-based maintenance and production lot-sizing

    NARCIS (Netherlands)

    Peng, H.; van Houtum, G.J.J.A.N.

    2016-01-01

    Due to the development of sensor technologies nowadays, condition-based maintenance (CBM) programs can be established and optimized based on the data collected through condition monitoring. The CBM activities can significantly increase the uptime of a machine. However, they should be conducted in a

  10. Basic Concept and Theoretical Study of Condition-based Maintenance for Power Transmission System

    Institute of Scientific and Technical Information of China (English)

    LIMing; HAN Xueshan; YANG Ming; GUO Zhihong

    2011-01-01

    The appropriate maintenance time for the single equipment can be found easily and efficiently under the background of condition-based maintenance. However, from the perspective of the whole power system, discrepancy between equipment individual and the whole power system would appear. Once this discrepancy can not be coordinated, it will certainly cause contradiction and conflict between individual equipment and the whole system, and lose the integral efficiency. To solve this contradiction and conflicts is of significant meaning.

  11. An open-source automated continuous condition-based maintenance platform for commercial buildings

    Energy Technology Data Exchange (ETDEWEB)

    Katipamula, Srinivas; Gowri, Krishnan; Hernandez, George

    2016-09-09

    This paper describes one such reference process that can be deployed to provide continuous automated conditioned-based maintenance management for buildings that have BIM, a building automation system (BAS) and a computerized maintenance management software (CMMS) systems. The process can be deployed using an open source transactional network platform, VOLTTRON™, designed for distributed sensing and controls and supports both energy efficiency and grid services.

  12. Development and Implementation of a Condition Based Maintenance Program for Geothermal Power Plants; FINAL

    International Nuclear Information System (INIS)

    Steve Miller; Jim Eddy; Murray Grande; Shawn Bratt; Manuchehr Shirmohamadi

    2002-01-01

    This report describes the development of the RCM team, identifying plant assets and developing an asset hierarchy, the development of sample Failure Mode Effects Analysis (FMEAs), identifying and prioritizing plant systems and components for RCM analysis, and identifying RCM/CBM software/hardware vendors. It also includes the Failure Mode Effects Analysis (FMEA) for all Class I Systems, Maintenance Task Assignments, use of Conditioned Based Maintenance (CBM) Tools and Displays of the RCM software System Development to date

  13. A model for determining condition-based maintenance policies for deteriorating multi-component systems

    NARCIS (Netherlands)

    Hontelez, J.A.M.; Wijnmalen, D.J.D.

    1993-01-01

    We discuss a method to determine strategies for preventive maintenance of systems consisting of gradually deteriorating components. A model has been developed to compute not only the range of conditions inducing a repair action, but also inspection moments based on the last known condition value so

  14. A Condition Based Maintenance Approach to Forecasting B-1 Aircraft Parts

    Science.gov (United States)

    2017-03-23

    Air Force Institute of Technology AFIT Scholar Theses and Dissertations 3-23-2017 A Condition Based Maintenance Approach to Forecasting B-1 Aircraft...component’s life history where reliability forecasts could be stipulated based on a component’s current condition . One of the major issues their report noted...Engine Condition Monitoring System Specification. Contract Number DOT-CG-80513-A. Grand Prairie, TX. Air Force Materiel Command. (2011) Requirements For

  15. A review on condition-based maintenance optimization models for stochastically deteriorating system

    International Nuclear Information System (INIS)

    Alaswad, Suzan; Xiang, Yisha

    2017-01-01

    Condition-based maintenance (CBM) is a maintenance strategy that collects and assesses real-time information, and recommends maintenance decisions based on the current condition of the system. In recent decades, research on CBM has been rapidly growing due to the rapid development of computer-based monitoring technologies. Research studies have proven that CBM, if planned properly, can be effective in improving equipment reliability at reduced costs. This paper presents a review of CBM literature with emphasis on mathematical modeling and optimization approaches. We focus this review on important aspects of the CBM, such as optimization criteria, inspection frequency, maintenance degree, solution methodology, etc. Since the modeling choice for the stochastic deterioration process greatly influences CBM strategy decisions, this review classifies the literature on CBM models based on the underlying deterioration processes, namely discrete- and continuous-state deterioration, and proportional hazard model. CBM models for multi-unit systems are also reviewed in this paper. This paper provides useful references for CBM management professionals and researchers working on CBM modeling and optimization. - Highlights: • A review on Condition-based maintenance (CBM) optimization models is presented. • The CBM models are classified based on the underlying deterioration processes. • Existing CBM models for both single- and multi-unit systems are reviewed. • Future essential research directions on CBM are identified.

  16. Cognitive Artificial Intelligence Method for Interpreting Transformer Condition Based on Maintenance Data

    Directory of Open Access Journals (Sweden)

    Karel Octavianus Bachri

    2017-07-01

    Full Text Available A3S(Arwin-Adang-Aciek-Sembiring is a method of information fusion at a single observation and OMA3S(Observation Multi-time A3S is a method of information fusion for time-series data. This paper proposes OMA3S-based Cognitive Artificial-Intelligence method for interpreting Transformer Condition, which is calculated based on maintenance data from Indonesia National Electric Company (PLN. First, the proposed method is tested using the previously published data, and then followed by implementation on maintenance data. Maintenance data are fused to obtain part condition, and part conditions are fused to obtain transformer condition. Result shows proposed method is valid for DGA fault identification with the average accuracy of 91.1%. The proposed method not only can interpret the major fault, it can also identify the minor fault occurring along with the major fault, allowing early warning feature. Result also shows part conditions can be interpreted using information fusion on maintenance data, and the transformer condition can be interpreted using information fusion on part conditions. The future works on this research is to gather more data, to elaborate more factors to be fused, and to design a cognitive processor that can be used to implement this concept of intelligent instrumentation.

  17. Bayesian Based Diagnostic Model for Condition Based Maintenance of Offshore Wind Farms

    Directory of Open Access Journals (Sweden)

    Masoud Asgarpour

    2018-01-01

    Full Text Available Operation and maintenance costs are a major contributor to the Levelized Cost of Energy for electricity produced by offshore wind and can be significantly reduced if existing corrective actions are performed as efficiently as possible and if future corrective actions are avoided by performing sufficient preventive actions. This paper presents an applied and generic diagnostic model for fault detection and condition based maintenance of offshore wind components. The diagnostic model is based on two probabilistic matrices; first, a confidence matrix, representing the probability of detection using each fault detection method, and second, a diagnosis matrix, representing the individual outcome of each fault detection method. Once the confidence and diagnosis matrices of a component are defined, the individual diagnoses of each fault detection method are combined into a final verdict on the fault state of that component. Furthermore, this paper introduces a Bayesian updating model based on observations collected by inspections to decrease the uncertainty of initial confidence matrix. The framework and implementation of the presented diagnostic model are further explained within a case study for a wind turbine component based on vibration, temperature, and oil particle fault detection methods. The last part of the paper will have a discussion of the case study results and present conclusions.

  18. Condition based monitoring, diagnosis and maintenance on operating equipments of a hydraulic generator unit

    International Nuclear Information System (INIS)

    Liu, X T; Feng, F Z; Si, A W

    2012-01-01

    According to performance characteristics of operating equipments in a hydraulic generator unit (HGU), the relative techniques on condition monitoring and fault diagnosis (CMFD) are introduced in this paper, especially the key technologies are emphasized, such as equipment monitoring, expert system (ES), intelligent diagnosis and condition based maintenance (CBM). Meanwhile, according to the instructor on CBM proposed by State electric power corporation, based on integrated mode, the main steps on implementation of CBM are discussed in this paper.

  19. Statistical Learning Framework with Adaptive Retraining for Condition-Based Maintenance

    International Nuclear Information System (INIS)

    An, Sang Ha; Chang, Soon Heung; Heo, Gyun Young; Seo, Ho Joon; Kim, Su Young

    2009-01-01

    As systems become more complex and more critical in our daily lives, the need for the maintenance based on the reliable monitoring and diagnosis has become more apparent. However, in reality, the general opinion has been that 'maintenance is a necessary evil' or 'nothing can be done to improve maintenance costs'. Perhaps these were true statements twenty years ago when many of the diagnostic technologies were not fully developed. The developments of microprocessor or computer based instrumentation that can be used to monitor the operating condition of plant equipment, machinery and systems have provided the means to manage the maintenance operation. They have provided the means to reduce or eliminate unnecessary repairs, prevent catastrophic machine failures and reduce the negative impact of the maintenance operation on the profitability of manufacturing and production plants. Condition-based maintenance (CBM) techniques help determine the condition of in-service equipment in order to predict when maintenance should be performed. Most of the statistical learning techniques are only valid as long as the physics of a system does not change. If any significant change such as the replacement of a component or equipment occurs in the system, the statistical learning model should be re-trained or re-developed to adapt the new system. In this research, authors will propose a statistical learning framework which can be applicable for various CBMs, and the concept of the adaptive retraining technique will be described to support the execution of the framework so that the monitoring system does not need to be re-developed or re-trained even though there are any significant changes in the system or component

  20. Earnings with Condition Based Maintenance; Ganhos com manutencao preditiva baseada em dados de processo em tempo real

    Energy Technology Data Exchange (ETDEWEB)

    Barabas, Elizabeth [Softbrasil Automacao, Sao Paulo, SP (Brazil)

    2008-07-01

    Keeping active in perfect functioning is essential for any company. Today, the maintenance has been performed in most of the stops for maintenance. In a modern industrial environment, where the systems provide data and process information in real time, it is possible bring the performance of the plant to a optimized level, through the maintenance based on condition of equipment. This work described the earnings with CBM (Condition Based Maintenance)

  1. The business case for condition-based maintenance: a hybrid (non-) financial approach

    NARCIS (Netherlands)

    Tiddens, W.W.; Tinga, T.; Braaksma, A.J.J.; Brouwer, O.; Cepin, Marko; Bris, Radim

    2017-01-01

    Although developing business cases is key for evaluating project success, the costs and benefits of condition-based maintenance (CBM) implementations are often not explicitly defined and evaluated. Using the design science methodology, we developed a hybrid business case approach to help managers

  2. Knowledge lost in data : Organizational impediments to condition-based maintenance in the process industry

    NARCIS (Netherlands)

    van de Kerkhof, Roland; Akkermans, Henk; Noorderhaven, Niels; Zijm, H.; Klumpp, M.; Clausen, U.; Ten Hompel, M.

    2016-01-01

    In this chapter we report on a pilot study of Condition-Based Maintenance (CBM) in the process industries, such as the steelmaking- and chemical industries, and propose a diagnostic instrument for systematically analysing the challenges to the successful implementation and execution of a CBM

  3. A condition-based maintenance policy for multi-component systems with Lévy copulas dependence

    International Nuclear Information System (INIS)

    Li, Heping; Deloux, Estelle; Dieulle, Laurence

    2016-01-01

    In this paper, we propose a new condition-based maintenance policy for multi-component systems taking into account stochastic and economic dependences. The stochastic dependence between components due to common environment is modelled by Lévy copulas. Its influence on the maintenance optimization is investigated with different dependence degrees. On the issue of economic dependence providing opportunities to group maintenance activities, a new maintenance decision rule is proposed which permits maintenance grouping. In order to evaluate the performance of the proposed maintenance policy, we compare it to the classical maintenance policies. - Highlights: • A new adaptive maintenance policy for grouping maintenance actions is proposed. • The impacts of both economic and stochastic dependences are investigated. • The performance of the proposed maintenance policy is evaluated under different system configurations. • The stochastic dependence is modelled by Lévy copulas. • The proposed maintenance decision rule can take full advantage of economic and stochastic dependences.

  4. Knowledge based maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, A [Hamburgische Electacitaets-Werke AG Hamburg (Germany)

    1998-12-31

    The establishment of maintenance strategies is of crucial significance for the reliability of a plant and the economic efficiency of maintenance measures. Knowledge about the condition of components and plants from the technical and business management point of view therefore becomes one of the fundamental questions and the key to efficient management and maintenance. A new way to determine the maintenance strategy can be called: Knowledge Based Maintenance. A simple method for determining strategies while taking the technical condition of the components of the production process into account to the greatest possible degree which can be shown. A software with an algorithm for Knowledge Based Maintenance leads the user during complex work to the determination of maintenance strategies for this complex plant components. (orig.)

  5. Knowledge based maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, A. [Hamburgische Electacitaets-Werke AG Hamburg (Germany)

    1997-12-31

    The establishment of maintenance strategies is of crucial significance for the reliability of a plant and the economic efficiency of maintenance measures. Knowledge about the condition of components and plants from the technical and business management point of view therefore becomes one of the fundamental questions and the key to efficient management and maintenance. A new way to determine the maintenance strategy can be called: Knowledge Based Maintenance. A simple method for determining strategies while taking the technical condition of the components of the production process into account to the greatest possible degree which can be shown. A software with an algorithm for Knowledge Based Maintenance leads the user during complex work to the determination of maintenance strategies for this complex plant components. (orig.)

  6. Single-stage Kanban system with deterioration failures and condition-based preventive maintenance

    International Nuclear Information System (INIS)

    Xanthopoulos, A.S.; Koulouriotis, D.E.; Botsaris, P.N.

    2015-01-01

    Despite the fact that the fields of pull type production control policies and condition-based preventive maintenance have much in common contextually, they have evolved independently up to now. In this investigation, an attempt is made to bridge the gap between these two branches of knowledge by introducing the single-stage Kanban system with deterioration failures and condition-based preventive maintenance. The formalism of continuous time Markov chains is used to model the system and expressions for eight performance metrics are derived. Two important, from a managerial perspective, constrained optimization problems for the proposed model are defined where the objective is the simultaneous optimization of the Kanban policy, the preventive maintenance policy and the inspection schedule under conflicting performance criteria. Multiple instances of each optimization problem are solved by means of the augmented Lagrangian genetic algorithm. The results from the optimization trials coupled by the results from extensive numerical examples facilitate the thorough investigation of the system’s behaviour. - Highlights: • Kanban system with deterioration failures and preventive maintenance is introduced. • The system is modeled as a continuous time Markov chain. • Expressions for eight performance metrics are derived. • The behavior of the system is studied through numerical examples. • Optimization results for selected performance metrics are presented

  7. An improved segmentation-based HMM learning method for Condition-based Maintenance

    International Nuclear Information System (INIS)

    Liu, T; Lemeire, J; Cartella, F; Meganck, S

    2012-01-01

    In the domain of condition-based maintenance (CBM), persistence of machine states is a valid assumption. Based on this assumption, we present an improved Hidden Markov Model (HMM) learning algorithm for the assessment of equipment states. By a good estimation of initial parameters, more accurate learning can be achieved than by regular HMM learning methods which start with randomly chosen initial parameters. It is also better in avoiding getting trapped in local maxima. The data is segmented with a change-point analysis method which uses a combination of cumulative sum charts (CUSUM) and bootstrapping techniques. The method determines a confidence level that a state change happens. After the data is segmented, in order to label and combine the segments corresponding to the same states, a clustering technique is used based on a low-pass filter or root mean square (RMS) values of the features. The segments with their labelled hidden state are taken as 'evidence' to estimate the parameters of an HMM. Then, the estimated parameters are served as initial parameters for the traditional Baum-Welch (BW) learning algorithms, which are used to improve the parameters and train the model. Experiments on simulated and real data demonstrate that both performance and convergence speed is improved.

  8. Heuristic hybrid game approach for fleet condition-based maintenance planning

    International Nuclear Information System (INIS)

    Feng, Qiang; Bi, Xiong; Zhao, Xiujie; Chen, Yiran; Sun, Bo

    2017-01-01

    The condition-based maintenance (CBM) method is commonly used to select appropriate maintenance opportunities according to equipment status over a period of time. The CBM of aircraft fleets is a fleet maintenance planning problem. In this problem, mission requirements, resource constraints, and aircraft statuses are considered to find an optimal strategy set. Given that the maintenance strategies for each aircraft are finite, fleet CBM can be treated as a combinatorial optimization problem. In this study, the process of making a decision on the CBM of military fleets is analyzed. The fleet CBM problem is treated as a two-stage dynamic decision-making problem. Aircraft are divided into dispatch and standby sets; thus, the problem scale is significantly reduced. A heuristic hybrid game (HHG) approach comprising a competition game and a cooperative game is proposed on the basis of heuristic rule. In the dispatch set, a competition game approach is proposed to search for a local optimal strategy matrix. A cooperative game method for the two sets is also proposed to ensure global optimization. Finally, a case study regarding a fleet comprising 20 aircraft is conducted, with the results proving that the approach efficiently generates outcomes that meet the mission risk-oriented schedule requirement. - Highlights: • A new heuristic hybrid game method for fleet condition-based maintenance is proposed. • The problem is simplified by hierarchical solving based on dispatch and standby set. • The local optimal solution is got by competition game algorithm for dispatch set. • The global optimal solution is got by cooperative game algorithm between two sets.

  9. Quantified Risk Ranking Model for Condition-Based Risk and Reliability Centered Maintenance

    Science.gov (United States)

    Chattopadhyaya, Pradip Kumar; Basu, Sushil Kumar; Majumdar, Manik Chandra

    2017-06-01

    In the recent past, risk and reliability centered maintenance (RRCM) framework is introduced with a shift in the methodological focus from reliability and probabilities (expected values) to reliability, uncertainty and risk. In this paper authors explain a novel methodology for risk quantification and ranking the critical items for prioritizing the maintenance actions on the basis of condition-based risk and reliability centered maintenance (CBRRCM). The critical items are identified through criticality analysis of RPN values of items of a system and the maintenance significant precipitating factors (MSPF) of items are evaluated. The criticality of risk is assessed using three risk coefficients. The likelihood risk coefficient treats the probability as a fuzzy number. The abstract risk coefficient deduces risk influenced by uncertainty, sensitivity besides other factors. The third risk coefficient is called hazardous risk coefficient, which is due to anticipated hazards which may occur in the future and the risk is deduced from criteria of consequences on safety, environment, maintenance and economic risks with corresponding cost for consequences. The characteristic values of all the three risk coefficients are obtained with a particular test. With few more tests on the system, the values may change significantly within controlling range of each coefficient, hence `random number simulation' is resorted to obtain one distinctive value for each coefficient. The risk coefficients are statistically added to obtain final risk coefficient of each critical item and then the final rankings of critical items are estimated. The prioritization in ranking of critical items using the developed mathematical model for risk assessment shall be useful in optimization of financial losses and timing of maintenance actions.

  10. Present state of condition based maintenance (CBM) and its future problem

    International Nuclear Information System (INIS)

    Hashimoto, Satoshi; Nogami, Takeki; Sugiyama, Naoki

    2008-01-01

    New inspection system of the nuclear power plant will be introduced from 2008. In this feature, eleven experts from electric utilities, venders and academia described their views or activities about Condition Based Maintenance (CBM) with a new inspection system attracting attention. These are titled as 'Electric utilities view on CBM and its technology', Deployment results of developed CBM technologies', 'Valve diagnostic analysis support system with wireless technology applied', 'Portable vibration checker', 'Tribology diagnosis with no overhaul', 'Infrared thermograph diagnosis', 'Pipewall thinning inspection and management' and, in addition, the US trend and also the development trend of the CBM advancement technology in the vender and university. CBM technology will be introduced step-by-step and contribute to establish reliability based maintenance. (T. Tanaka)

  11. Analysis of the possibility of applying a condition-based maintenance model on an example of tank weapons

    Directory of Open Access Journals (Sweden)

    Igor J. Epler

    2013-12-01

    Full Text Available For any modern army it is very important to continuously maintain a high degree of operational (combat readiness (availability in order to maximize the effectiveness of the use of technical systems. Since determination and prediction of technical states and failures of technical systems in engineering, especially in armament, are difficult due to the impossibility of continuous condition monitoring with appropriate measuring equipment there is a need for a maintenance model that would be most helpful in taking timely action maintenance. In this paper, the subject of research is a model of maintenance of the M-84 tank  weapoons systems.   IntroductionThe M-84 tank is one of the most promising technical systems in the Serbian Army. Its use and modifications are foreseen in the next ten years. The  M-84 is characterized by good tactical and technical characteristics. It has a powerful 125 mm cannon, coupled 7.62 mm machine gun and 12.7 mm anti-aircraft machine gun. The M-84 tank has an automatic battery charger and a fire control system. The fire control system enables fast target tracking and stabilization of the cannon barrel, which is a prerequisite for timely and favorable effect on the target. There are certain ambiguities in the existing model of maintenance of tank weapons.   Technical diagnostics Technical diagnostics, as a part of the process of condition-based maintenance, should determine technical conditions of components or technical systems with certain accuracy at a point in time.   Maintenance strategy A maintenance strategy can be defined as a variant of a maintenance system determined by a concept, organization and character of maintenance procedures, as well as the relationship between the various levels at which maintenance is performed. It is defined for technical system parts, individual technical systems and for system maintenance as a whole. The basic maintenance strategies implemented today are: -      corrective

  12. An Optimization Method for Condition Based Maintenance of Aircraft Fleet Considering Prognostics Uncertainty

    Directory of Open Access Journals (Sweden)

    Qiang Feng

    2014-01-01

    Full Text Available An optimization method for condition based maintenance (CBM of aircraft fleet considering prognostics uncertainty is proposed. The CBM and dispatch process of aircraft fleet is analyzed first, and the alternative strategy sets for single aircraft are given. Then, the optimization problem of fleet CBM with lower maintenance cost and dispatch risk is translated to the combinatorial optimization problem of single aircraft strategy. Remain useful life (RUL distribution of the key line replaceable Module (LRM has been transformed into the failure probability of the aircraft and the fleet health status matrix is established. And the calculation method of the costs and risks for mission based on health status matrix and maintenance matrix is given. Further, an optimization method for fleet dispatch and CBM under acceptable risk is proposed based on an improved genetic algorithm. Finally, a fleet of 10 aircrafts is studied to verify the proposed method. The results shows that it could realize optimization and control of the aircraft fleet oriented to mission success.

  13. Prognostics and Condition-Based Maintenance: A New Approach to Precursive Metrics

    International Nuclear Information System (INIS)

    Jarrell, Donald B.; Sisk, Daniel R.; Bond, Leonard J.

    2004-01-01

    The assumptions used in the design basis of process equipment have always been as much art as science. The usually imprecise boundaries of the equipments' operational envelope provide opportunities for two major improvements in the operations and maintenance (O and M) of process machinery: (a) the actual versus intended machine environment can be understood and brought into much better alignment and (b) the end goal can define O and M strategies in terms of life cycle and economic management of plant assets.Scientists at the Pacific Northwest National Laboratory (PNNL) have performed experiments aimed at understanding and controlling aging of both safety-specific nuclear plant components and the infrastructure that supports essential plant processes. In this paper we examine the development of aging precursor metrics and their correlation with degradation rate and projected machinery failure.Degradation-specific correlations have been developed at PNNL that will allow accurate physics-based diagnostic and prognostic determinations to be derived from a new view of condition-based maintenance. This view, founded in root cause analysis, is focused on quantifying the primary stressor(s) responsible for degradation in the component of interest and formulating a deterministic relationship between the stressor intensity and the resulting degradation rate. This precursive relationship between the performance, degradation, and underlying stressor set is used to gain a first-principles approach to prognostic determinations. A holistic infrastructure approach, as applied through a conditions-based maintenance framework, will allow intelligent, automated diagnostic and prognostic programming to provide O and M practitioners with an understanding of the condition of their machinery today and an assurance of its operational state tomorrow

  14. Improvement of condition-based maintenance technology by utilization of thermography

    International Nuclear Information System (INIS)

    Shimada, Hiroki

    2004-01-01

    In the United States, condition-based maintenance technology comprising IR thermography (hereafter ''thermography'' for short) has been regarded in recent years as the established means for effectively improvement the performance of accident-preventive measures for nuclear power stations. As very few nuclear power plants in Japan have been utilizing the technology, measures for allowing power station personnel to use the technology with ease have been studied on an empirical basis. First, in view of improving the measuring efficiency to determine temperatures more accurately with a single measurement, principal factors affecting the measured temperature values have been analyzed. As a result, it has been found effective for accurate temperature measurement to make use of the table to radiation rates that have been determined for each facility coating specification by using a black body tape and to determine the measuring spot by avoiding rear heat sources (influence of reflection ratio) and background noise (influence of scattered light). Concurrently, as a result of determining the IR attenuation in the atmosphere, thermographic measurement has been found feasible without any significant attenuation as long as the distance is below 10 meters. Further, every power station facility (mainly electrical facilities) that is immune to thermography has been identified. These study results have been documented in the form of the ''Thermography Measurement Manual'' by also including in it the descriptions on abnormal thermal images and the judgment criteria at elevated temperatures that have been used in the United States. Based on these accomplishments, condition-based maintenance technology employing thermography has been applied to on-site investigation of nuclear power stations, and the effectiveness of thermography-aided accident-prevention has been demonstrated by detecting locally temperature rising spots of power cable joints. Moreover, with respect to maintenance

  15. Optimal condition-based maintenance decisions for systems with dependent stochastic degradation of components

    International Nuclear Information System (INIS)

    Hong, H.P.; Zhou, W.; Zhang, S.; Ye, W.

    2014-01-01

    Components in engineered systems are subjected to stochastic deterioration due to the operating environmental conditions, and the uncertainty in material properties. The components need to be inspected and possibly replaced based on preventive or failure replacement criteria to provide the intended and safe operation of the system. In the present study, we investigate the influence of dependent stochastic degradation of multiple components on the optimal maintenance decisions. We use copula to model the dependent stochastic degradation of components, and formulate the optimal decision problem based on the minimum expected cost rule and the stochastic dominance rules. The latter is used to cope with decision maker's risk attitude. We illustrate the developed probabilistic analysis approach and the influence of the dependency of the stochastic degradation on the preferred decisions through numerical examples

  16. Comparative study of heuristics algorithms in solving flexible job shop scheduling problem with condition based maintenance

    Directory of Open Access Journals (Sweden)

    Yahong Zheng

    2014-05-01

    Full Text Available Purpose: This paper focuses on a classic optimization problem in operations research, the flexible job shop scheduling problem (FJSP, to discuss the method to deal with uncertainty in a manufacturing system.Design/methodology/approach: In this paper, condition based maintenance (CBM, a kind of preventive maintenance, is suggested to reduce unavailability of machines. Different to the simultaneous scheduling algorithm (SSA used in the previous article (Neale & Cameron,1979, an inserting algorithm (IA is applied, in which firstly a pre-schedule is obtained through heuristic algorithm and then maintenance tasks are inserted into the pre-schedule scheme.Findings: It is encouraging that a new better solution for an instance in benchmark of FJSP is obtained in this research. Moreover, factually SSA used in literature for solving normal FJSPPM (FJSP with PM is not suitable for the dynamic FJSPPM. Through application in the benchmark of normal FJSPPM, it is found that although IA obtains inferior results compared to SSA used in literature, it performs much better in executing speed.Originality/value: Different to traditional scheduling of FJSP, uncertainty of machines is taken into account, which increases the complexity of the problem. An inserting algorithm (IA is proposed to solve the dynamic scheduling problem. It is stated that the quality of the final result depends much on the quality of the pre-schedule obtained during the procedure of solving a normal FJSP. In order to find the best solution of FJSP, a comparative study of three heuristics is carried out, the integrated GA, ACO and ABC. In the comparative study, we find that GA performs best in the three heuristic algorithms. Meanwhile, a new better solution for an instance in benchmark of FJSP is obtained in this research.

  17. Safety constraints applied to an adaptive Bayesian condition-based maintenance optimization model

    International Nuclear Information System (INIS)

    Flage, Roger; Coit, David W.; Luxhøj, James T.; Aven, Terje

    2012-01-01

    A model is described that determines an optimal inspection and maintenance scheme for a deteriorating unit with a stochastic degradation process with independent and stationary increments and for which the parameters are uncertain. This model and resulting maintenance plans offers some distinct benefits compared to prior research because the uncertainty of the degradation process is accommodated by a Bayesian approach and two new safety constraints have been applied to the problem: (1) with a given subjective probability (degree of belief), the limiting relative frequency of one or more failures during a fixed time interval is bounded; or (2) the subjective probability of one or more failures during a fixed time interval is bounded. In the model, the parameter(s) of a condition-based inspection scheduling function and a preventive replacement threshold are jointly optimized upon each replacement and inspection such as to minimize the expected long run cost per unit of time, but also considering one of the specified safety constraints. A numerical example is included to illustrate the effect of imposing each of the two different safety constraints.

  18. Prognostics and Condition Based Maintenance: A New Approach to Precursive Metrics

    International Nuclear Information System (INIS)

    Jarrell, Donald B.; Sisk, Daniel R.; Bond, Leonard J.

    2002-01-01

    Scientists at the Pacific Northwest National Laboratory (PNNL) have examined the necessity for understanding and controlling the aging process of both safety-specific plant components and the infrastructure that supports these processes. In this paper we examine the preliminary development of aging precursor metrics and their correlation with degradation rate and projected machine failure. Degradation specific correlations are currently being developed at PNNL that will allow accurate physics-based diagnostic and prognostic determinations to be derived from a new view of condition based maintenance. This view, founded in root cause analysis, is focused on quantifying the primary stressor(s) responsible for degradation in the component of interest. The derivative relationship between the performance, degradation and the underlying stressor set is used to gain a first principles approach to prognostic determinations. The assumptions used for the design basis of process equipment have always been as much art as science and for this reason have been misused or relegated into obscurity in all but the nuclear industry. The ability to successfully link degradation and expected equipment life to stressor intensity level is valuable in that it quantifies the degree of machine stress for a given production level. This allows two major improvements in the O and M of process machinery: (1) the actual versus intended machine environment can be understood and brought into much better alignment, and (2) the end goal can define operations and maintenance strategies in terms of life cycle and economic management of plant assets. A holistic infrastructure approach, as applied through a CBM framework, will allow intelligent, automated diagnostic and prognostic programs to provide O and M practitioners with an understanding of the condition of their machinery today and an assurance of its operational state tomorrow

  19. Polyspectral signal analysis techniques for condition based maintenance of helicopter drive-train system

    Science.gov (United States)

    Hassan Mohammed, Mohammed Ahmed

    For an efficient maintenance of a diverse fleet of air- and rotorcraft, effective condition based maintenance (CBM) must be established based on rotating components monitored vibration signals. In this dissertation, we present theory and applications of polyspectral signal processing techniques for condition monitoring of critical components in the AH-64D helicopter tail rotor drive train system. Currently available vibration-monitoring tools are mostly built around auto- and cross-power spectral analysis which have limited performance in detecting frequency correlations higher than second order. Studying higher order correlations and their Fourier transforms, higher order spectra, provides more information about the vibration signals which helps in building more accurate diagnostic models of the mechanical system. Based on higher order spectral analysis, different signal processing techniques are developed to assess health conditions of different critical rotating-components in the AH-64D helicopter drive-train. Based on cross-bispectrum, quadratic nonlinear transfer function is presented to model second order nonlinearity in a drive-shaft running between the two hanger bearings. Then, quadratic-nonlinearity coupling coefficient between frequency harmonics of the rotating shaft is used as condition metric to study different seeded shaft faults compared to baseline case, namely: shaft misalignment, shaft imbalance, and combination of shaft misalignment and imbalance. The proposed quadratic-nonlinearity metric shows better capabilities in distinguishing the four studied shaft settings than the conventional linear coupling based on cross-power spectrum. We also develop a new concept of Quadratic-Nonlinearity Power-Index spectrum, QNLPI(f), that can be used in signal detection and classification, based on bicoherence spectrum. The proposed QNLPI(f) is derived as a projection of the three-dimensional bicoherence spectrum into two-dimensional spectrum that

  20. Data mining and statistical process control for condition-based maintenance; Datamining und statistische Prozesskontrolle zur zustandsorientierten Instandhaltung

    Energy Technology Data Exchange (ETDEWEB)

    Deeskow, Peter; Steinmetz, Urs; Hay, Martin [Evonik Energy Services, Essen (Germany)

    2008-07-01

    Optimum, condition-based maintenance should balance the commercial consequences of an efficiency loss or a component failure and the cost of maintenance. This requires an early and highly reliable detection of abnormalities of the component/unit behaviour. For this purpose key performance indicators (KPIs) can be used which are online calculated from operational measurements and which solely depend on the component condition and do not depend on other influencing factors such as operation mode, load or ambient conditions. Software tools using data mining methods can facilitate the definition and calculation of such KPIs. (orig.)

  1. Condition-based maintenance effectiveness for series–parallel power generation system—A combined Markovian simulation model

    International Nuclear Information System (INIS)

    Azadeh, A.; Asadzadeh, S.M.; Salehi, N.; Firoozi, M.

    2015-01-01

    Condition-based maintenance (CBM) is an increasingly applicable policy in the competitive marketplace as a means of improving equipment reliability and efficiency. Not only has maintenance a close relationship with safety but its costs also make it even more attractive issue for researchers. This study proposes a model to evaluate the effectiveness of CBM policy compared to two other maintenance policies: Corrective Maintenance (CM) and Preventive Maintenance (PM). Maintenance policies are compared through two system performance indicators: reliability and cost. To estimate the reliability and costs of the system, the proposed Markovian discrete-event simulation model is developed under each of these policies. The applicability and usefulness of the proposed Markovian simulation model is illustrated for a series–parallel power generation system. The simulated characteristics of CBM system include its prognostics efficiency to estimate remaining useful life of the equipment. Results show that with an efficient prognostics, CBM policy is an effective strategy compared to other maintenance strategies. - Highlights: • A model is developed to evaluate the effectiveness of CBM policy. • Maintenance policies are compared through reliability and cost. • A Markovian simulation model is developed. • A series–parallel power generation system is considered. • CBM is an effective strategy compared to others

  2. Experimental study on the plant state estimation for the condition-based maintenance

    International Nuclear Information System (INIS)

    Harada, J. I.; Takahashi, M.; Kitamura, M.; Wakabayashi, T.

    2006-01-01

    A framework of maintenance support system based on the plant state estimation using diverse methods has been proposed and the validity of the plant state estimation methods has been experimentally evaluated. The focus has been set on the construction of the BN for the objective system with the scale and complexity as same as real world systems. Another focus has been set on the other functions for maintenance support system such as signal processing tool and similarity matching. The validity of the proposed inference method has been confirmed through numerical experiments. (authors)

  3. Integrated Instrumentation and Sensor Systems Enabling Condition-Based Maintenance of Aerospace Equipment

    Directory of Open Access Journals (Sweden)

    Richard C. Millar

    2012-01-01

    Full Text Available The objective of the work reported herein was to use a systems engineering approach to guide development of integrated instrumentation/sensor systems (IISS incorporating communications, interconnections, and signal acquisition. These require enhanced suitability and effectiveness for diagnostics and health management of aerospace equipment governed by the principles of Condition-based maintenance (CBM. It is concluded that the systems engineering approach to IISS definition provided clear benefits in identifying overall system requirements and an architectural framework for categorizing and evaluating alternative architectures, relative to a bottom up focus on sensor technology blind to system level user needs. CBM IISS imperatives identified include factors such as tolerance of the bulk of aerospace equipment operational environments, low intrusiveness, rapid reconfiguration, and affordable life cycle costs. The functional features identified include interrogation of the variety of sensor types and interfaces common in aerospace equipment applications over multiplexed communication media with flexibility to allow rapid system reconfiguration to adapt to evolving sensor needs. This implies standardized interfaces at the sensor location (preferably to open standards, reduced wire/connector pin count in harnesses (or their elimination through use of wireless communications.

  4. Advanced maintenance strategies for power plant operators - introducing inter-plant life cycle management. ZES research focus 'condition-based maintenance in power engineering'

    Energy Technology Data Exchange (ETDEWEB)

    Graeber, U.

    2003-07-01

    The optimisation of maintenance activities observed in recent years can be attributed above all to the use and continuing development of testing and diagnostic techniques, to the increased level of system and component automation and to more efficient work organisation. Despite the considerable success of these efforts, the potential for further cost reductions is still far from exhausted. The risks connected to reliability, availability and safety need to be analysed in greater detail in order to ensure the sustainability of the savings already achieved as well as those yet to be realised. The systematic application of condition-based maintenance and the introduction of structured life cycle management are essential prerequisites. Within the framework of its ''Condition-Based Maintenance in Power Engineering'' research focus, the Energy Research Centre (ZES) has set up a specialist network in which experts from various institutes belonging to the Faculty of Mechanical Engineering and the Faculty of Informatic, Electrical Engineering and Information Technology can develop interdisciplinary solutions for advanced maintenance strategies. The ZES offers the industry a platform for cooperating on current issues relating to the supply of energy and supports the movement towards sustainable improvements to competitiveness through research and consulting activities. It applies professional project and quality management procedures to ensure that contracts covering interdisciplinary topics and projects are handled in a coherent manner. (orig.)

  5. Advanced maintenance strategies for power plant operators - introducing inter-plant life cycle management. ZES research focus 'condition-based maintenance in power engineering'

    International Nuclear Information System (INIS)

    Graeber, U.

    2003-01-01

    The optimisation of maintenance activities observed in recent years can be attributed above all to the use and continuing development of testing and diagnostic techniques, to the increased level of system and component automation and to more efficient work organisation. Despite the considerable success of these efforts, the potential for further cost reductions is still far from exhausted. The risks connected to reliability, availability and safety need to be analysed in greater detail in order to ensure the sustainability of the savings already achieved as well as those yet to be realised. The systematic application of condition-based maintenance and the introduction of structured life cycle management are essential prerequisites. Within the framework of its ''Condition-Based Maintenance in Power Engineering'' research focus, the Energy Research Centre (ZES) has set up a specialist network in which experts from various institutes belonging to the Faculty of Mechanical Engineering and the Faculty of Informatic, Electrical Engineering and Information Technology can develop interdisciplinary solutions for advanced maintenance strategies. The ZES offers the industry a platform for cooperating on current issues relating to the supply of energy and supports the movement towards sustainable improvements to competitiveness through research and consulting activities. It applies professional project and quality management procedures to ensure that contracts covering interdisciplinary topics and projects are handled in a coherent manner. (orig.)

  6. A condition-based maintenance policy with non-periodic inspections for a two-unit series system

    International Nuclear Information System (INIS)

    Castanier, B.; Grall, A.; Berenguer, C.

    2005-01-01

    This paper considers a condition-based maintenance policy for a two-unit deteriorating system. Each unit is subject to gradual deterioration and is monitored by sequential non-periodic inspections. It can be maintained by good as new preventive or corrective replacements. Every inspection or replacement entails a set-up cost and a component-specific unit cost but if actions on the two components are combined, the set-up cost is charged only once. A parametric maintenance decision framework is proposed to coordinate inspection/replacement of the two components and minimize the long-run maintenance cost of the system. A stochastic model is developed on the basis of the semi-regenerative properties of the maintained system state and the associated cost model is used to assess and optimize the performance of the maintenance model. Numerical experiments emphasize the interest of a control of the operation groupings

  7. Availability analysis of mechanical systems with condition-based maintenance using semi-Markov and evaluation of optimal condition monitoring interval

    Science.gov (United States)

    Kumar, Girish; Jain, Vipul; Gandhi, O. P.

    2018-03-01

    Maintenance helps to extend equipment life by improving its condition and avoiding catastrophic failures. Appropriate model or mechanism is, thus, needed to quantify system availability vis-a-vis a given maintenance strategy, which will assist in decision-making for optimal utilization of maintenance resources. This paper deals with semi-Markov process (SMP) modeling for steady state availability analysis of mechanical systems that follow condition-based maintenance (CBM) and evaluation of optimal condition monitoring interval. The developed SMP model is solved using two-stage analytical approach for steady-state availability analysis of the system. Also, CBM interval is decided for maximizing system availability using Genetic Algorithm approach. The main contribution of the paper is in the form of a predictive tool for system availability that will help in deciding the optimum CBM policy. The proposed methodology is demonstrated for a centrifugal pump.

  8. A condition-based maintenance of a dependent degradation-threshold-shock model in a system with multiple degradation processes

    International Nuclear Information System (INIS)

    Caballé, N.C.; Castro, I.T.; Pérez, C.J.; Lanza-Gutiérrez, J.M.

    2015-01-01

    This paper proposes a condition-based maintenance strategy for a system subject to two dependent causes of failure: degradation and sudden shocks. The internal degradation is reflected by the presence of multiple degradation processes in the system. Degradation processes start at random times following a Non-homogeneous Poisson process and their growths are modelled by using a gamma process. When the deterioration level of a degradation process exceeds a predetermined value, we assume that a degradation failure occurs. Furthermore, the system is subject to sudden shocks that arrive at the system following a Doubly Stochastic Poisson Process. A sudden shock provokes the total breakdown of the system. Thus, the state of the system is evaluated at inspection times and different maintenance tasks can be carried out. If the system is still working at an inspection time, a preventive maintenance task is performed if the deterioration level of a degradation process exceeds a certain threshold. A corrective maintenance task is performed if the system is down at an inspection time. A preventive (corrective) maintenance task implies the replacement of the system by a new one. Under this maintenance strategy, the expected cost rate function is obtained. A numerical example illustrates the analytical results. - Highlights: • A condition-based maintenance model is proposed. • Two dependent causes of failure are considered: deterioration and external shocks. • Deterioration is given by multiple degradation processes growing by a gamma process. • The initiation of degradation processes follows a Non-homogeneous Poisson process. • External shocks arrive at the system by using a Doubly Stochastic Poisson Process

  9. A prediction method based on grey system theory in equipment condition based maintenance

    International Nuclear Information System (INIS)

    Yan, Shengyuan; Yan, Shengyuan; Zhang, Hongguo; Zhang, Zhijian; Peng, Minjun; Yang, Ming

    2007-01-01

    Grey prediction is a modeling method based on historical or present, known or indefinite information, which can be used for forecasting the development of the eigenvalues of the targeted equipment system and setting up the model by using less information. In this paper, the postulate of grey system theory, which includes the grey generating, the sorts of grey generating and the grey forecasting model, is introduced first. The concrete application process, which includes the grey prediction modeling, grey prediction, error calculation, equal dimension and new information approach, is introduced secondly. Application of a so-called 'Equal Dimension and New Information' (EDNI) technology in grey system theory is adopted in an application case, aiming at improving the accuracy of prediction without increasing the amount of calculation by replacing old data with new ones. The proposed method can provide a new way for solving the problem of eigenvalue data exploding in equal distance effectively, short time interval and real time prediction. The proposed method, which was based on historical or present, known or indefinite information, was verified by the vibration prediction of induced draft fan of a boiler of the Yantai Power Station in China, and the results show that the proposed method based on grey system theory is simple and provides a high accuracy in prediction. So, it is very useful and significant to the controlling and controllable management in safety production. (authors)

  10. Condition-based dynamic maintenance operations planning and grouping. Application to commercial heavy vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Bouvard, K., E-mail: keomany.bouvard@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France); Artus, S., E-mail: samuel.artus@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes - Institut Charles Delaunay and UMR CNRS 6279 - 12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Cocquempot, V., E-mail: vincent.cocquempot@univ-lille1.f [Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France)

    2011-06-15

    This paper aims at presenting a method to optimize the maintenance planning for a commercial heavy vehicle. Such a vehicle may be considered as a multi-components system. Grouping maintenance operations related to each component reduces the global maintenance cost of the system. Classically, the optimization problem is solved using a priori reliability characteristics of components. Two types of methods may be used, i.e. static or dynamic methods. Static methods provide a fixed maintenance planning, whereas dynamic methods redefine the groups of maintenance operations at each decision time. Dynamic procedures can incorporate component information such as component states or detected failures. For deteriorating systems, reliability characteristics of each component may be estimated thanks to deterioration models and may be updated when a degradation measure is available. This additional information on degradation features allows to better follow the real state of each component and to improve the maintenance planning.

  11. Application of T2 Control Charts and Hidden Markov Models in Condition-Based Maintenance at Thermoelectric Power Plants

    Directory of Open Access Journals (Sweden)

    Emilija Kisić

    2015-01-01

    Full Text Available An innovative approach to condition-based maintenance of coal grinding subsystems at thermoelectric power plants is proposed in the paper. Coal mill grinding tables become worn over time and need to be replaced through time-based maintenance, after a certain number of service hours. At times such replacement is necessary earlier or later than prescribed, depending on the quality of the coal and of the grinding table itself. Considerable financial losses are incurred when the entire coal grinding subsystem is shut down and the grinding table found to not actually require replacement. The only way to determine whether replacement is necessary is to shut down and open the entire subsystem for visual inspection. The proposed algorithm supports condition-based maintenance and involves the application of T2 control charts to distinct acoustic signal parameters in the frequency domain and the construction of Hidden Markov Models whose observations are coded samples from the control charts. In the present research, the acoustic signals were collected by coal mill monitoring at the thermoelectric power plant “Kostolac” in Serbia. The proposed approach provides information about the current condition of the grinding table.

  12. Computational framework for risk-based planning of inspections, maintenance, and condition monitoring using discrete Bayesian networks

    DEFF Research Database (Denmark)

    Nielsen, Jannie Sønderkær; Sørensen, John Dalsgaard

    2018-01-01

    This paper presents a computational framework for risk-based planning of inspections and repairs for deteriorating components. Two distinct types of decision rules are used to model decisions: simple decision rules that depend on constants or observed variables (e.g. inspection outcome...... expecte d life-cycle costs. For advanced decision rules, simulations are performed to estimate the expected costs, and dBNs are used within the simulations for decision-making. Information from inspections and condition monitoring are included if available. An example in the paper demonstrates...... the framework and the implemented strategies and decision rules, including various types of condition-based maintenance. The strategies using advanced decision rules lead to reduced costs compared to the simple decision rules when condition monitoring is applied, and the value of condition monitoring...

  13. The dynamic pressure measurements of the nuclear reactor coolant for condition-based maintenance of the reactor

    International Nuclear Information System (INIS)

    Es-Saheb, M.H.H.

    1990-01-01

    The condition-based maintenance of the nuclear reactor, by monitoring and measuring the instantaneous dynamic pressure distribution of the coolant (water) impact on the solid surfaces of the reactor during operation is presented. The behaviour of water domes (jets) produced by underwater explosions of small changes of P.E.T.N. at various depths in two different size cylindrical containers, which simulate the nuclear reactor, is investigated. Water surface domes (jets) from the underwater explosions are photographed. Depending on the depth of the charge, curved and flat top jets of up to 455 mm diameter and impact speeds of up to 70 m/sec. are observed. The instabilities in the dome surfaces are observed and the instantaneous profiles are analysed. It is found that, in all cases tested, the maximum pressure takes place at the center of the jet and could reach up to 3.0 times the on-dimensional impact pressure value. The use of their measurements, as online monitoring for condition-based maintenance and design-out maintenance is discussed. 18 refs

  14. Energy-autonomous wireless vibration sensor for condition-based maintenance of machinery

    NARCIS (Netherlands)

    Wang, Z.; Bouwens, F.; Vullers, R.; Petré, F.; Devos, S.

    2011-01-01

    This paper addresses the development of an energy-autonomous wireless vibration sensor for condition-based monitoring of machinery. Such technology plays an increasingly important role in modern manufacturing industry. In this work, energy harvesting is realized by resorting to a custom designed

  15. Condition-Based Maintenance Strategy for Production Systems Generating Environmental Damage

    Directory of Open Access Journals (Sweden)

    L. Tlili

    2015-01-01

    Full Text Available We consider production systems which generate damage to environment as they get older and degrade. The system is submitted to inspections to assess the generated environmental damage. The inspections can be periodic or nonperiodic. In case an inspection reveals that the environmental degradation level has exceeded the critical level U, the system is considered in an advanced deterioration state and will have generated significant environmental damage. A corrective maintenance action is then performed to renew the system and clean the environment and a penalty has to be paid. In order to prevent such an undesirable situation, a lower threshold level L is considered to trigger a preventive maintenance action to bring back the system to a state as good as new at a lower cost and without paying the penalty. Two inspection policies are considered (periodic and nonperiodic. For each one of them, a mathematical model and a numerical procedure are developed to determine simultaneously the preventive maintenance (PM threshold L∗ and the inspection sequence which minimize the average long-run cost per time unit. Numerical calculations are performed to illustrate the proposed maintenance policies and highlight their main characteristics with respect to relevant input parameters.

  16. Context-Dependent Prognostics and Health Assessment: A Condition-Based Maintenance Approach That Supports Mission Compliance

    Energy Technology Data Exchange (ETDEWEB)

    Allgood, G.O.; Kercel, S.W.

    1999-04-19

    In today's manufacturing environment, plants, systems, and equipment are being asked to perform at levels not thought possible a decade ago. The intent is to improve process operations and equipment reliability, availability, and maintainability without costly upgrades. Of course these gains must be achieved without impacting operational performance. Downsizing is also taking its toll on operations. Loss of personnel, particularly those who represent the corporate history, is depleting US industries of their valuable experiential base which has been relied on so heavily in the past. These realizations are causing companies to rethink their condition-based maintenance policies by moving away from reacting to equipment problems to taking a proactive approach by anticipating needs based on market and customer requirements. This paper describes a different approach to condition-based maintenance-context-dependent prognostics and health assessment. This diagnostic capability is developed around a context-dependent model that provides a capability to anticipate impending failures and determine machine performance over a protracted period of time. This prognostic capability links operational requirements to an economic performance model. In this context, a system may provide 100% operability with less than 100% functionality. This paradigm is used to facilitate optimal logistic supply and support.

  17. A Novel Idea for Optimizing Condition-Based Maintenance Using Genetic Algorithms and Continuous Event Simulation Techniques

    Directory of Open Access Journals (Sweden)

    Mansoor Ahmed Siddiqui

    2017-01-01

    Full Text Available Effective maintenance strategies are of utmost significance for system engineering due to their direct linkage with financial aspects and safety of the plants’ operation. At a point where the state of a system, for instance, level of its deterioration, can be constantly observed, a strategy based on condition-based maintenance (CBM may be affected; wherein upkeep of the system is done progressively on the premise of monitored state of the system. In this article, a multicomponent framework is considered that is continuously kept under observation. In order to decide an optimal deterioration stage for the said system, Genetic Algorithm (GA technique has been utilized that figures out when its preventive maintenance should be carried out. The system is configured into a multiobjective problem that is aimed at optimizing the two desired objectives, namely, profitability and accessibility. For the sake of reality, a prognostic model portraying the advancements of deteriorating system has been employed that will be based on utilization of continuous event simulation techniques. In this regard, Monte Carlo (MC simulation has been shortlisted as it can take into account a wide range of probable options that can help in reducing uncertainty. The inherent benefits proffered by the said simulation technique are fully utilized to display various elements of a deteriorating system working under stressed environment. The proposed synergic model (GA and MC is considered to be more effective due to the employment of “drop-by-drop approach” that permits successful drive of the related search process with regard to the best optimal solutions.

  18. Material degradation analysis and maintenance decisions based on material condition monitoring during in-service inspections

    International Nuclear Information System (INIS)

    Yacout, A.M.; Orechwa, Y.

    1996-03-01

    The degradation of the material in critical components is shown to be an effective measure which can be used to compute the risk adjusted economic penalty associated with different maintenance decisions. The approach of estimating the probability, with confidence interval, of the time that a prescribed degradation level is exceeded is shown to be practical, as demonstrated in the analysis of irradiated fuel cladding. The methodology for the estimation of the probability is predicated on the existence of a parsimonious and robust mixed-effects model of the evolution of the degradation. This model, in general, relates measured surrogates of the degradation level to computed or measured variables, which characterize the environment during the operating history of the component. We propose and demonstrate the efficacy of using an artificial neural network, constructed via a genetic supervisor, as an aid in developing the requisite mixed-effects model and testing its continued validity as new data are obtained

  19. Condition-based maintenance. With application on a heat exchanger and a pump; Tillstaandsbaserat underhaall. Med applikation paa en vaermevaexlare och en pump

    Energy Technology Data Exchange (ETDEWEB)

    Raaberg, Martin; Slaetteke, Ola

    2012-02-15

    Regular maintenance is required to extend the life of a plant's components and maintain optimum operation. Unnecessary outages from maintenance may inflict large monetary losses. Therefore, a cost-effective maintenance system should be condition-based rather than time-based. The optimal maintenance scheme requires a process model and a forecast of the operation conditions of this model. At least one of the model parameters should be affected by the maintenance. To determine the actual status of the plant, the model parameters should be estimated. This requires an analysis of available data to detect degradation of the critical components performance. Base load plants usually operate at maximum production or as close to maximum as possible at stabile conditions during long periods. Since the operating time is long and usually at high load in base load plants, advanced control systems and maintenance planning is most profitable in such plants. Advanced control and process optimization requires dynamic process models. Due to the long operating time of a base load plant, it is natural that its process characteristics change, such as wear and fouling. This means that models must be adapted continuously in order to generate a good approximation and thus a good basis for control and optimization. The problem is that the stable operation condition of a base load plant prevents a good estimate of model parameters through the lack of excitation of the process

  20. CH-47D Rotating System Fault Sensing for Condition Based Maintenance

    Science.gov (United States)

    2011-03-01

    aircraft. 8 Figure 2.3: CH-47D Rotor Trim Tab [10] Several methods are utilized to prevent this imbalance. Mechanical dampers filled with a viscous and...pressurized fluid , commonly referred to as lag dampers , link the rotor blades to the rotor hub and attempt to minimize this out-of-balance condition...and requires the use of a flap bearing. This flap bearing and the lag damper are both potential sources of vibration if they are not performing to

  1. Multipoint dynamically reconfigure adaptive distributed fiber optic acoustic emission sensor (FAESense) system for condition based maintenance

    Science.gov (United States)

    Mendoza, Edgar; Prohaska, John; Kempen, Connie; Esterkin, Yan; Sun, Sunjian; Krishnaswamy, Sridhar

    2010-09-01

    This paper describes preliminary results obtained under a Navy SBIR contract by Redondo Optics Inc. (ROI), in collaboration with Northwestern University towards the development and demonstration of a next generation, stand-alone and fully integrated, dynamically reconfigurable, adaptive fiber optic acoustic emission sensor (FAESense™) system for the in-situ unattended detection and localization of shock events, impact damage, cracks, voids, and delaminations in new and aging critical infrastructures found in ships, submarines, aircraft, and in next generation weapon systems. ROI's FAESense™ system is based on the integration of proven state-of-the-art technologies: 1) distributed array of in-line fiber Bragg gratings (FBGs) sensors sensitive to strain, vibration, and acoustic emissions, 2) adaptive spectral demodulation of FBG sensor dynamic signals using two-wave mixing interferometry on photorefractive semiconductors, and 3) integration of all the sensor system passive and active optoelectronic components within a 0.5-cm x 1-cm photonic integrated circuit microchip. The adaptive TWM demodulation methodology allows the measurement of dynamic high frequnency acoustic emission events, while compensating for passive quasi-static strain and temperature drifts. It features a compact, low power, environmentally robust 1-inch x 1-inch x 4-inch small form factor (SFF) package with no moving parts. The FAESense™ interrogation system is microprocessor-controlled using high data rate signal processing electronics for the FBG sensors calibration, temperature compensation and the detection and analysis of acoustic emission signals. Its miniaturized package, low power operation, state-of-the-art data communications, and low cost makes it a very attractive solution for a large number of applications in naval and maritime industries, aerospace, civil structures, the oil and chemical industry, and for homeland security applications.

  2. Maintenance cost avoidance through comprehensive condition monitoring

    International Nuclear Information System (INIS)

    Miller, G.P.; McClymonds, S.L.

    1990-01-01

    Condition monitoring, the measurement and trending of a critical parameter for predictive maintenance, has reached new levels of acceptance and application within the utility and manufacturing industry. Commercially available systems extend well beyond traditional vibration-monitoring systems to include such areas as online wear, crack and leak detection, and stress monitoring. The challenge facing industry is to integrate the information generated from condition monitoring. Current studies indicate that the effectiveness of predictive maintenance depends much more on the program that is established to apply the monitoring techniques than on the monitoring equipment itself. This paper presents a five-phase approach to developing a condition monitoring program

  3. Condition-based maintenance for a system subject to a non-homogeneous wear process with a wear rate transition

    Energy Technology Data Exchange (ETDEWEB)

    Fouladirad, Mitra, E-mail: mitra.fouladirad@utt.f [Universite de Technologie de Troyes, Institut Charles Delaunay, FRE CNRS 2848, 12 rue Marie Curie, 10010 Troyes (France); Grall, Antoine [Universite de Technologie de Troyes, Institut Charles Delaunay, FRE CNRS 2848, 12 rue Marie Curie, 10010 Troyes (France)

    2011-06-15

    The aim of this paper is to propose an adaptive maintenance model for a gradually deteriorating system. The system considered initially deteriorates with a nominal deterioration rate and at an unknown time the system's deterioration rate changes and the new deterioration rate is a time-dependent function. To deal with the transition of mode of deterioration in the framework of the maintenance decision rule an adequate online change detection algorithm is used. The maintenance decision rule is chosen in order to minimise the total maintenance cost including the cost of unavailability. The main result of this paper is to point out the interest of using a detection algorithm and hence the appreciation of a decision rule which takes into account transitions in the deterioration rate.

  4. Condition-based maintenance for a system subject to a non-homogeneous wear process with a wear rate transition

    International Nuclear Information System (INIS)

    Fouladirad, Mitra; Grall, Antoine

    2011-01-01

    The aim of this paper is to propose an adaptive maintenance model for a gradually deteriorating system. The system considered initially deteriorates with a nominal deterioration rate and at an unknown time the system's deterioration rate changes and the new deterioration rate is a time-dependent function. To deal with the transition of mode of deterioration in the framework of the maintenance decision rule an adequate online change detection algorithm is used. The maintenance decision rule is chosen in order to minimise the total maintenance cost including the cost of unavailability. The main result of this paper is to point out the interest of using a detection algorithm and hence the appreciation of a decision rule which takes into account transitions in the deterioration rate.

  5. A Bayesian network based approach for integration of condition-based maintenance in strategic offshore wind farm O&M simulation models

    DEFF Research Database (Denmark)

    Nielsen, Jannie Sønderkær; Sørensen, John Dalsgaard; Sperstad, Iver Bakken

    2018-01-01

    In the overall decision problem regarding optimization of operation and maintenance (O&M) for offshore wind farms, there are many approaches for solving parts of the overall decision problem. Simulation-based strategy models accurately capture system effects related to logistics, but model...... to generate failures and CBM tasks. An example considering CBM for wind turbine blades demonstrates the feasibility of the approach....

  6. A STEPPING STONE TOWARDS KNOWLEDGE BASED MAINTENANCE

    OpenAIRE

    G. Waeyenbergh; L. Pintelon; L. Gelders

    2012-01-01

    Maintenance decision making becomes more and more a management concern. Some decades ago, maintenance was still often considered as an unavoidable side effect of production. The perception of maintenance has evolved considerably. One of the current issues is the maintenance concept, being the mix of maintenance interventions and the general framework for determining this mix. In this paper we describe a modular framework, called Knowledge Based Maintenance, for developing a customised mainten...

  7. Gym-based exercise was more costly compared with home-based exercise with telephone support when used as maintenance programs for adults with chronic health conditions: cost-effectiveness analysis of a randomised trial

    Directory of Open Access Journals (Sweden)

    Paul Jansons

    2018-01-01

    Registration: ACTRN12610001035011. [Jansons P, Robins L, O’Brien L, Haines T (2018 Gym-based exercise was more costly compared with home-based exercise with telephone support when used as maintenance programs for adults with chronic health conditions: cost-effectiveness analysis of a randomised trial. Journal of Physiotherapy 64: 48–54

  8. Gym-based exercise and home-based exercise with telephone support have similar outcomes when used as maintenance programs in adults with chronic health conditions: a randomised trial

    Directory of Open Access Journals (Sweden)

    Paul Jansons

    2017-07-01

    Trial registration: ACTRN12610001035011. [Jansons P, Robins L, O’Brien L, Haines T (2017 Gym-based exercise and home-based exercise with telephone support have similar outcomes when used as maintenance programs in adults with chronic health conditions: a randomised trial. Journal of Physiotherapy 63: 154–160

  9. Maintenance Decision Making based on different types of data fusion

    OpenAIRE

    Galar, D.; Gustafson, A.; Tormos Martínez, Bernardo Vicente; Berges, Luis

    2012-01-01

    [EN] Over the last decade, system integration is applied more as it allows organizations to streamline business processes. A recent development in the asset engineering management is to leverage the investment already made in process control systems. This allows the operations, maintenance, and process control teams to monitor and determine new alarm level based on the physical condition data of the critical machines. Condition-based maintenance (CBM) is a maintenance philosophy base...

  10. Performance-based inspection and maintenance strategies

    International Nuclear Information System (INIS)

    Vesely, W.E.

    1995-01-01

    Performance-based inspection and maintenance strategies utilize measures of equipment performance to help guide inspection and maintenance activities. A relevant measure of performance for safety system components is component unavailability. The component unavailability can also be input into a plant risk model such as a Probabilistic Risk Assessment (PRA) to determine the associated plant risk performance. Based on the present and projected unavailability performance, or the present and projected risk performance, the effectiveness of current maintenance activities can be evaluated and this information can be used to plan future maintenance activities. A significant amount of information other than downtimes or failure times is collected or can be collected when an inspection or maintenance is conducted which can be used to estimate the component unavailability. This information generally involves observations on the condition or state of the component or component piecepart. The information can be detailed such as the amount of corrosion buildup or can be general such as the general state of the component described as ' high degradation', ' moderate degradation', or ' low degradation'. Much of the information collected in maintenance logs is qualitative and fuzzy. As part of an NRC Research program on performance-based engineering modeling, approaches have been developed to apply Fuzzy Set Theory to information collected on the state of the component to determine the implied component or component piecepart unavailability. Demonstrations of the applications of Fuzzy Set Theory are presented utilizing information from plant maintenance logs. The demonstrations show the power of Fuzzy Set Theory in translating engineering information to reliability and risk implications

  11. A STEPPING STONE TOWARDS KNOWLEDGE BASED MAINTENANCE

    Directory of Open Access Journals (Sweden)

    G. Waeyenbergh

    2012-01-01

    Full Text Available Maintenance decision making becomes more and more a management concern. Some decades ago, maintenance was still often considered as an unavoidable side effect of production. The perception of maintenance has evolved considerably. One of the current issues is the maintenance concept, being the mix of maintenance interventions and the general framework for determining this mix. In this paper we describe a modular framework, called Knowledge Based Maintenance, for developing a customised maintenance concept. After describing the general framework and its decision support use, some case experiences are given. This experience covers some elements of the proposed framework.

  12. Case Based Asset Maintenance for the Electric Equipment

    International Nuclear Information System (INIS)

    Kim, Ji-Hyeon; Jung, Jae-Cheon; Chang, Young-Woo; Chang, Hoon-Seon; Kim, Jae-Cheol; Kim, Hang-Bae; Kim, Kyu-Ho; Hur, Yong; Lee, Dong-Chul

    2006-01-01

    The electric equipment maintenance strategies are changing from PM(Preventive Maintenance) or CM(Corrective Maintenance) to CBM(Condition Based Maintenance). The main benefits of CBM are reduced possibility of service failures of critical equipment and reduced costs or maintenance work. In CBM, the equipment status need to be monitored continuously and a decision should be made whether an equipment need to be repaired or replaced. For the maintenance decision making, the CBR(Case Base Reasoning) system is introduced. The CBR system receives the current equipment status and retrieves the case based historic database to determine any possible equipment failure under current conditions. In retrieving the case based historic data, the suggested DSS(Decision Support System) uses a reasoning engine with an equipment/asset ontology that describes the equipment subsumption relationships

  13. Maintenance Planning of Offshore Wind Turbine using Condition Monitoring Information

    DEFF Research Database (Denmark)

    Ramírez, José G. Rangel; Sørensen, John Dalsgaard

    2009-01-01

    Deterioration processes such as fatigue and corrosion are typically affecting offshore structures. To "control" this deterioration, inspection and maintenance activities are developed. Probabilistic methodologies represent an important tool to identify the suitable strategy to inspect and control...... the deterioration in structures such as offshore wind turbines (OWT). Besides these methods, the integration of condition monitoring information (CMI) can optimize the mitigation activities as an updating tool. In this paper, a framework for risk-based inspection and maintenance planning (RBI) is applied for OWT....... With the integration of CMI by means Bayesian inference, a slightly change of first inspection times are coming up, influenced by the reduction of the uncertainty and harsher or milder external agents....

  14. Maintenance of electromechanical equipment in quality organization under operating conditions

    International Nuclear Information System (INIS)

    Mercier, J.P.

    1984-01-01

    The paper outlines the principles adopted by the Thermal Production Service of Electricite de France on the basis of the experience of the first years of operation of its 900 MW(e)PWR units for the purpose of improving quality organization in operating conditions in respect of the maintenance of electromechanical safety equipment. This organization is based on application of the usual principles for quality assurance, adapted in accordance with current French regulations. The paper first recalls the now traditional methods of applying the principles of quality organization in the area of equipment maintenance. It then defines particular so-called ''delicate'' activities which, in accordance with the above regulations, are subjected to additional quality organizational procedures; this applies in particular to the area of pre-maintenance preparation and studies and to the control exercised by the French safety authorities over the execution of those activities. The paper explains how the application of the regulations improves maintenance practices compared with standard quality organization. It describes how the attempt to establish a frontier between these two types of activity (current and ''delicate'') has led to the definition of a classification criterion which is technically correct and simple to use and is based on the professional skills of those performing each activity. The paper then describes in greater detail the principal rules for the performance of those tasks which come under the standard organization and those to which more stringent criteria apply. Lastly, it explains the thinking behind equipment surveillance programmes and the analysis of anomalies discovered through surveillance measures or brought to light by operating incidents, the aim of these being to benefit from the experience gained

  15. Ageing model considering effects of maintenance and working conditions

    International Nuclear Information System (INIS)

    Martorell, S.; Sanchez, A.; Serradell, V.

    1998-01-01

    Nowadays, there is some doubt about building new Nuclear Power Plants (NPPs). Instead, there is a growing interest in analyzing the possibility to extend current NPP operation where life management programs play an important role. The evolution of the NPP safety depends on the evolution of the reliability of its safety components as a function of their age along the NPP operational life. In this paper, a new age-dependent reliability model is presented, which includes parameters related to surveillance and maintenance effectiveness and working conditions, both environmental and operational, of the equipment. This model may be used to support NPP life management and life extension programs by improving or optimizing surveillance and maintenance tasks using risk and cost models based on such an age-dependent reliability model. The results of the sensitivity study in the application show that the selection of the most appropriate maintenance strategy would directly depend on the previous parameters and very important differences are expected to appear under certain circumstance. (Author) 7 refs

  16. An Aircraft Lifecycle Approach for the Cost-Benefit Analysis of Prognostics and Condition-Based Maintenance-Based on Discrete-Event Simulation

    Science.gov (United States)

    2014-10-02

    MPD. This manufacturer documentation contains maintenance tasks with specification of intervals and required man-hours that are to be carried out...failures, without consideration of false alarms and missed failures (see also section 4.1.3). The task redundancy rate is the percentage of preventive...Prognostics and Health Management ROI return on investment RUL remaining useful life TCG task code group SB Service Bulletin XML Extensible Markup

  17. Simulation based comparison of predictive maintenance policies

    NARCIS (Netherlands)

    Tinga, Tiedo; Janssen, R.H.P.; Steenbergen, R.; van Gelder, P.

    2013-01-01

    When an asset is operated in variable conditions, its operational efficiency can be improved significantly when the maintenance is performed in a dynamic manner. This means that variations in usage and operating environment are taken into account when deciding on the length of the maintenance

  18. Experience based reliability centered maintenance

    International Nuclear Information System (INIS)

    Haenninen, S.; Laakso, K.

    1993-03-01

    The systematic analysis and documentation of operating experiences should be included in a living NPP life management program. Failure mode and effects and maintenance effects analyses are suitable methods for analysis of the failure and corrective maintenance experiences of equipment. Combined use of the information on occurred functional failures and the decision tree logic of the reliability centered maintenance identifies applicable and effective preventive maintenance tasks of equipment in an old plant. In this study the electrical motor drives of closing and isolation valves (MOV) of TVO and Loviisa nuclear power plants were selected to serve as pilot study objects. The study was limited to valve drives having actuators manufactured by AUMA in Germany. The fault and maintenance history of MOVs from 1981 up to and including October 1991 in different safety and process systems at TVO 1 and 2 nuclear power units was at first analyzed in a systematic way. The scope of the components studied was 81 MOVs in safety-related systems and 127 other MOVs per each TVO unit. In the case of the Loviisa plant, the observation period was limited to three years, i.e. from February 1989 up to February 1992. The scope of the Loviisa 1 and 2 components studied was 44 respectively 95 MOVs. (25 refs., 22 figs., 8 tabs.)

  19. Ageing Management Based Maintenance at ETRR-II

    Energy Technology Data Exchange (ETDEWEB)

    Kamoon, A.; Ali, A., E-mail: akamoun2004@yahoo.com [Inshas Nuclear Research Centre, Egyptian Atomic Energy Authority (EAEA), Cairo (Egypt)

    2014-08-15

    The second research reactor of Egypt, ETRR-II, is an open pool type multi-purpose reactor of 22 MW that has been in operation since 1998. The main purposes of ETRR-II are the production of radioisotopes, personnel training, research and development. Ageing management of ETRR-II is based on the maintenance programme. This programme was planned to have a proactive maintenance strategy that mainly depends on adequate preventive and predictive maintenance. Screening of SSCs is based on safety classes, needs and quality levels. The operation condition and maintenance history are the basis to assess the level of degradation. The ultimate aim of the maintenance team is to perform adequate maintenance work only when it is really necessary. The objectives of the ageing management based maintenance are to maintain and improve equipment availability, confirm compliance with operational limits and conditions, and detect and correct any abnormal condition that might affect reactor safety. The programme also helps to detect trends in ageing so that a plan for mitigating ageing effects can be prepared and implemented. Reactor service conditions are monitored through many parameters and conditions such as conductivity and pH of coolant water, water radiochemical analysis, thermal and hydraulic parameters, a leak detection system, corrosion rate of piping, vibration level of rotating equipment and control rod drop time.

  20. Maintenance evaluation using risk based criteria

    International Nuclear Information System (INIS)

    Torres Valle, A.

    1996-01-01

    The maintenance evaluation is currently performed by using economic and, in some case, technical equipment failure criteria, however this is done to a specific equipment level. In general, when statistics are used the analysis for maintenance optimization are made isolated and whit a post mortem character; The integration provided by mean of Probabilistic Safety assessment (PSA) together with the possibilities of its applications, allow for evaluation of maintenance on the basis of broader scope criteria in regard to those traditionally used. The evaluate maintenance using risk based criteria, is necessary to follow a dynamic and systematic approach, in studying the maintenance strategy, to allow for updating the initial probabilistic models, for including operational changes that often take place during operation of complex facilities. This paper proposes a dynamic evaluation system of maintenance task. The system is illustrated by means of a practical example

  1. Sustainable resilience in property maintenance: encountering changing weather conditions

    DEFF Research Database (Denmark)

    Cox, Rimante Andrasiunaite; Nielsen, Susanne Balslev

    2014-01-01

    Purpose: The purpose of the study is to develop a methodological approach for project management to integrate sustainability and resilience planning in property maintenance as an incremental strategy for upgrading existing properties to meet new standards for sustainable and climate resilient...... buildings. Background: Current maintenance practice is focused on the technical standard of buildings, with little consideration of sustainability and resilience. There is a need to develop tools for incorporating sustainable resilience into maintenance planning. Approach: The study is primarily theoretical......, developing the concept of sustainable resilience for changing weather conditions Results: The paper suggests a decision support methodology that quantifies sustainable resilience for the analytical stages of property maintenance planning. Practical Implications: The methodology is generic and expected users...

  2. Operation and maintenance requirements of system design bases

    International Nuclear Information System (INIS)

    Banerjee, A.K.; Hanley, N.E.

    1989-01-01

    All system designs make assumptions about system operation testing, inspection, and maintenance. Existing industry codes and standards explicitly address design requirements of new systems, while issues related to system and plant reliability, life, design margins, effects of service conditions, operation, maintenance, etc., usually are implicit. However, system/component design documents of existing power plants often address the code requirements without considering the operation, maintenance, inspection, and testing (OMIT) requirements. The nuclear industry is expending major efforts at most nuclear power plants to reassemble and/or reconstitute system design bases. Stone ampersand Webster Engineering Corporation (SWEC) recently addressed the OMIT requirements of system/component design as an integral part of a utility's preventive maintenance program. For each component, SWEC reviewed vendor recommendations, NPRDS data/industry experience, the existing maintenance program, component service conditions, and actual plant experience. A maintenance program that considers component service conditions and plant experience ensures a connection between maintenance and design basis. Root cause analysis of failure and engineering evaluation of service condition are part of the program. System/component OMIT requirements also are compared against system design, service condition, degradation mechanism, etc., through system/component life-cycle evaluation

  3. Integrated reliability condition monitoring and maintenance of equipment

    CERN Document Server

    Osarenren, John

    2015-01-01

    Consider a Viable and Cost-Effective Platform for the Industries of the Future (IOF) Benefit from improved safety, performance, and product deliveries to your customers. Achieve a higher rate of equipment availability, performance, product quality, and reliability. Integrated Reliability: Condition Monitoring and Maintenance of Equipment incorporates reliable engineering and mathematical modeling to help you move toward sustainable development in reliability condition monitoring and maintenance. This text introduces a cost-effective integrated reliability growth monitor, integrated reliability degradation monitor, technological inheritance coefficient sensors, and a maintenance tool that supplies real-time information for predicting and preventing potential failures of manufacturing processes and equipment. The author highlights five key elements that are essential to any improvement program: improving overall equipment and part effectiveness, quality, and reliability; improving process performance with maint...

  4. Risk Based Maintenance in Electricity Network Organisations

    NARCIS (Netherlands)

    Mehairjan, R.P.Y.

    2016-01-01

    Presently, maintenance management of assets in infrastructure utilities such as electricity, gas and water are widely undergoing changes towards new working environments. These are mainly driven against the background of stringent regulatory regimes, an ageing asset base, increased customer demands

  5. The use of condition monitoring information for maintenance planning and decision-making

    Energy Technology Data Exchange (ETDEWEB)

    Laakso, K.; Rosqvist, T. [VTT Industrial Systems (Finland); Paulsen, J.L. [Risoe National Lab., Roskilde (Denmark)

    2002-12-01

    A survey is presented outlining the use of condition monitoring information in three Nordic nuclear power plants. The questions of the survey relate to the role of condition monitoring in strategic, as well as operative, maintenance planning and decision-making. The survey indicates that condition monitoring is increasingly implemented at nuclear power plants, but very selectively and in a rather slow pace for predictive maintenance. A combined strategy of condition based maintenance and predetermined preventive maintenance is applied for important equipment such as main circulation pumps and steam turbines. A realistic aim is to reduce the number of costly or error prone maintenance and disassembling inspection activities by condition monitoring given that the approach enables a good diagnosis and prediction. Systematic follow-up and analysis of such condition monitoring information followed by a case-specific planning and decision making of timely and rightly directed maintenance actions can justify an extension of the intervals of a number of predetermined inspection, maintenance or periodic testing tasks. (au)

  6. Condition monitoring a key component in the preventive maintenance

    International Nuclear Information System (INIS)

    Isar, C.

    2006-01-01

    The preventive maintenance programs are necessary to ensure that nuclear safety significant equipment will function when it is supposed to. Diesel generator, pumps, motor operated valves and air operated control valves are typically operated every three months. When you drive a car, you depend on lot of sounds, the feel of the steering wheel and gauges to determine if the car is running correctly. Similarly with operating equipment for a power plant - sounds or vibration of the equipment or the gauges and test equipment indicate a problem or degradation, actions are taken to correct the deficiency. Due to safety and economical reason diagnostic and monitoring systems are of growing interest in all complex industrial production. Diagnostic systems are requested to detect, diagnose and localize faulty operating conditions at an early stage in order to prevent severe failures and to enable predictive and condition oriented maintenance. In this context it is a need for using various on-line and off-line condition monitoring and diagnostics, non-destructive inspection techniques and surveillance. The condition monitoring technique used in nuclear power plant Cernavoda are presented in this paper. The selection of components and parameters to be monitored, monitoring and diagnostics techniques used are incorporated into a preventive maintenance program. Modern measurement technique in combination with advanced computerized data processing and acquisition show new ways in the field of machine surveillance. The diagnostic capabilities of predictive maintenance technologies have increased recently year with advances made in sensor technologies. The paper will focus on the following condition monitoring technique: - oil analysis - acoustic leakage monitoring - thermography - valve diagnostics: motor operated valve, air operated valve and check valve - motor current signature - vibration monitoring and rotating machine monitoring and diagnostics For each condition monitoring

  7. Conditions of job performance quality during nuclear reactor maintenance

    International Nuclear Information System (INIS)

    Babos, K.; Takacs, J.

    1991-01-01

    The education and training programs of the maintenance personnel at the Paks Nuclear Power Plant, Hungary are described. In addition to well trained personnel, the conditions of job quality involves the preparation of job by proper check lists and availability of documentation, and the inspection and checking of the accomplishment of job tasks. Such an inspection procedure is proposed. (R.P.) 2 figs

  8. The machines maintenance conditions assessment in the plastic industry

    Directory of Open Access Journals (Sweden)

    Stanisław Borkowski

    2015-12-01

    Full Text Available The purpose, methodology, main findings, the originality of the subject area (research, way of using. The main research analysis purpose is a presentation, an assessment and an interpretation of the research findings on the machines maintenance conditions in the plastic industry. The research analysis was carried out with applying Technology ABC method and TPM coefficients calculations connected with Techno pak machine components maintenance. The research was carried out in the chosen manufacturing enterprise of the plastic industry. Research findings interpretation results have been introduced in the analyzed enterprise in the form of the manufacturing processes improvement.

  9. Condition based maintenance of a 20 kV-PE/XLPE-insulated cable network using the IRC-Analysis; Zustandsorientierte Instandhaltung eines polymerisolierten 20-kV-Kabelnetzes mit der IRC-Analyse. Moderne Diagnostik reduziert Stoerungsrate

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, G.; Kranz, H.G. [BUGH Wuppertal (Germany). Labs. fuer Hochspannungstechnik; Beigert, M.; Petzold, F. [Seba Dynatronic Mess- und Ortungstechnik GmbH, Baunach (Germany); Kneissl, C. [Bereich Konzeption und Messtechnik, Lech Elektrizitaetswerke AG, Augsburg (Germany)

    2001-10-22

    For a preventive maintenance of a polymer insulated cable network a destruction free estimation of the status of the buried PE/XLPE-cables is needed. This contribution presents a condition based maintenance concept which is based on the IRC-Analysis. With this concept a major German utility was able to reduce the amount of failures in a part of the 20kV-cable network. The general tendency of increasing faults was broken. (orig.) [German] Die praeventive Instandhaltung in polymerisolierten Kabelnetzen setzt eine zerstoerungsfreie Zustandbestimmung von gelegten PE/VPE-isolierten Kabeln voraus. Die-Verfasser beschreiben ein zustandsorientiertes Wartungskonzept auf Basis der IRC-Analyse, mit dem es gelungen ist, in einem Teil des 20-kV-Kabelnetzes eines Energieversorgers die in der Vergangenheit stetig steigende Stoerungsrate drastisch zu reduzieren. (orig.)

  10. Tools to support maintenance strategies under soft soil conditions

    Directory of Open Access Journals (Sweden)

    J. W. M. Lambert

    2015-11-01

    Full Text Available Costs for maintenance of infrastructure in municipalities with soft soil underground conditions, are estimated to be almost 40 % higher than in others. As a result, these municipalities meet financial problems that cause overdue maintenance. In some cases municipalities are even afraid to be unable to offer a minimum service level in future. In common, traditional practice, roads and sewerage systems have been constructed in trenches that consist of sandy material that replaces the upper meters of the soft soil. Under influence of its weight, this causes accelerated settlements of the construction. A number of alternative constructions have been developed, e.g. using light-weight materials to limit settlement velocity. In order to limit future maintenance costs, improvement of maintenance strategies is desired. Tools have been and will be developed to support municipalities in improving their maintenance strategies and save money by doing that. A model (BALANS that weighs the attractiveness of alternative solutions under different soil, environmental and economic circumstances, will be presented.

  11. Condition monitoring and maintenance of nuclear power plant concrete structures

    International Nuclear Information System (INIS)

    Orr, R.; Prasad, N.

    1988-01-01

    Nuclear power plant concrete structures are potentially subject to deterioration due to several environmental conditions, including weather exposure, ground water exposure, and sustained high temperature and radiation levels. The nuclear power plant are generally licensed for a term of 40 years. In order to maximize the return from the existing plants, feasibility studies are in progress for continued operation of many of these plants beyond the original licensed life span. This paper describes a study that was performed with an objective to define appropriate condition monitoring and maintenance procedures. A timely implementation of a condition monitoring and maintenance program would provide a valuable database and would provide justification for extension of the plant's design life. The study included concrete structures such as the containment buildings, interior structures, basemats, intake structures and cooling towers. Age-related deterioration at several operating power plants was surveyed and the potential degradation mechanisms have been identified

  12. Risk-based Operation and Maintenance for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Nielsen, Jannie Jessen

    2011-01-01

    For offshore wind turbines, costs to Operation and Maintenance (OM) are substantial, and can be expected to increase when wind farms are placed at deeper water depths and in more harsh environments. Traditional strategies for OM include corrective and preventive (scheduled and condition...... statistics and costs of the different operations. The different OM strategies are described and compared in an illustrative example with focus on which types of information that are needed. Special focus is on comparison between risk-based maintenance strategies and the conventional maintenance planning...... and are often the driving mechanisms for failures / faults that need maintenance. Observations of the degree of damage can increase the reliability of predictions and decrease the costs of OM if integrated in a risk-based framework theoretically based on pre-posterior Bayesian decision theory. The mathematical...

  13. Risk based maintenance: Resource requirements and organizational challenges

    International Nuclear Information System (INIS)

    Weerakkody, S.D.

    2000-01-01

    10CFR50.65 'Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants' required licensees to monitor the performance or condition of structures, systems, or components (SSCs) against licensee established goals, in a manner sufficient to provide reasonable assurance that such SSCs are capable of fulfilling their intended functions. The goals were required to be commensurate with safety significance and operating experience. Northeast Utilities relied upon PRAs to implement 10CFR50.65, which is also referred to as the 'Maintenance Rule'. The Maintenance Rule changed some aspects of maintenance of structures, systems, and components (SSC) at nuclear power plants. One objective of the rule was to focus the maintenance resources based on risk significance of components. This paper will discuss the organizational challenges and resource requirements associated with implementation of the Maintenance Rule at nuclear facilities that are supported by the Northeast Utilities Services Company (NUSCo). The paper will discuss (a) how these challenges were addressed, (b) the resources required for ongoing efforts to support the Maintenance Rule, and (c) several key safety benefits derived from the implementation of the Maintenance Rule. (author)

  14. Improvement of railway ballast maintenance approach, incorporating ballast geometry and fouling conditions

    Science.gov (United States)

    Sadeghi, J.; Motieyan-Najar, M. E.; Zakeri, J. A.; Yousefi, B.; Mollazadeh, M.

    2018-04-01

    Ballast plays an important role in the stability of railway track systems. The effectiveness of the ballast in maintaining the track stability is very much dependent on its mechanical conditions. The available ballast maintenance approaches are mainly based on only track geometry conditions (such as track profile) which do not sufficiently reflect the ballast mechanical behaviors. That is, the ballast potential of degradation (i.e., ballast long term behaviors) has been omitted. This makes the effectiveness of the current ballast maintenance approach questionable, indicating a need for a more comprehensive and effective ballast conditions assessment technique. In response to this need, two ballast condition indices based on ballast geometry degradation (BGI) and the level of ballast fouling (BFI) as the main indicators of ballast mechanical behavior were developed. The BGI is a function of the standard deviations of track alignment, unevenness and twist. The BFI was developed based on the data obtained from the ground penetration radar (GPR). Making use of the new indices, a more reliable maintenance algorithm was developed. Through illustrations of the applicability of the new maintenance algorithm in a railway line, it was shown that the new algorithm causes a considerable improvement in the maintenance effectiveness and an increase in the life cycle of railway tracks by making more effective allocation of resources and more accurate maintenance planning.

  15. Risk-Based Operation and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nielsen, Jannie Sønderkær

    to oil and gas structures. In addition, condition monitoring systems are often available, and the information should be taken into account when making decisions. In this thesis, methods for risk-based maintenance planning using Bayesian methods are investigated, with the aim of making optimal decisions......, but presently maintenance is not planned using advanced methods taking all available information into account in a consistent manner. Maintenance decisions can be made based on risk-based methods, where the total expected life cycle costs are minimized. Methods have been developed for assessing the corrective...... considering all available information. First, a theoretical damage model is formulated, the model is then updated using condition monitoring data, and the updated model is used as basis for risk-based decision making. Several approaches for solving the decision problems have been considered: various types...

  16. A Real-Time Quantitative Condition Alerting and Analysis Support System for Aircraft Maintenance, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Financial constraints and the need for improved operational efficiency are requiring airlines to emphasize "on-condition" maintenance over scheduled maintenance...

  17. Machine and lubricant condition monitoring for extended equipment lifetimes and predictive maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, M; Anderson, D P [Spectro Incorporated, Littleton, Massachusetts (United States)

    1998-12-31

    Predictive maintenance has gained wide acceptance as a cost cutting strategy in modern industry. Condition monitoring by lubricant analysis is one of the basic tools of a predictive maintenance program along with vibration monitoring, performance monitoring and thermography. In today`s modern power generation, manufacturing, refinery, transportation, mining, and military operations, the cost of equipment maintenance, service, and lubricants are ever increasing. Parts, labor, equipment downtime and lubricant prices and disposal costs are a primary concern in a well run maintenance management program. Machine condition monitoring based on oil analysis has become a prerequisite in most maintenance programs. Few operations can afford not to implement a program if they wish to remain competitive, and in some cases, profitable. This presentation describes a comprehensive Machine Condition Monitoring Program based on oil analysis. Actual operational condition monitoring programs will be used to review basic components and analytical requirements. Case histories will be cited as examples of cost savings, reduced equipment downtime and increased efficiencies of maintenance programs through a well managed oil analysis program. (orig.)

  18. Machine and lubricant condition monitoring for extended equipment lifetimes and predictive maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, M.; Anderson, D.P. [Spectro Incorporated, Littleton, Massachusetts (United States)

    1997-12-31

    Predictive maintenance has gained wide acceptance as a cost cutting strategy in modern industry. Condition monitoring by lubricant analysis is one of the basic tools of a predictive maintenance program along with vibration monitoring, performance monitoring and thermography. In today`s modern power generation, manufacturing, refinery, transportation, mining, and military operations, the cost of equipment maintenance, service, and lubricants are ever increasing. Parts, labor, equipment downtime and lubricant prices and disposal costs are a primary concern in a well run maintenance management program. Machine condition monitoring based on oil analysis has become a prerequisite in most maintenance programs. Few operations can afford not to implement a program if they wish to remain competitive, and in some cases, profitable. This presentation describes a comprehensive Machine Condition Monitoring Program based on oil analysis. Actual operational condition monitoring programs will be used to review basic components and analytical requirements. Case histories will be cited as examples of cost savings, reduced equipment downtime and increased efficiencies of maintenance programs through a well managed oil analysis program. (orig.)

  19. Preventive maintenance: optimization of time - based discard decisions at the bruce nuclear generating station

    International Nuclear Information System (INIS)

    Doyle, E.K.; Jardine, A.K.S.

    2001-01-01

    The use of various maintenance optimization techniques at Bruce has lead to cost effective preventive maintenance applications for complex systems. As previously reported at ICONE 6 in New Orleans, 1996, several innovative practices reduced Reliability Centered Maintenance costs while maintaining the accuracy of the analysis. The optimization strategy has undergone further evolution and at the present an Integrated Maintenance Program (IMP) is in place where an Expert Panel consisting of all players/experts proceed through each system in a disciplined fashion and reach agreement on all items under a rigorous time frame. It is well known that there are essentially 3 maintenance based actions that can flow from a Maintenance Optimization Analysis: condition based maintenance, time based maintenance and time based discard. The present effort deals with time based discard decisions. Maintenance data from the Remote On-Power Fuel Changing System was used. (author)

  20. The Road Pavement Condition Index (PCI Evaluation and Maintenance: A Case Study of Yemen

    Directory of Open Access Journals (Sweden)

    Karim Fareed M. A.

    2016-12-01

    Full Text Available The pavement condition index (PCI is a simple, convenient and inexpensive way to monitor the condition of the surface of roads, identify maintenance and rehabilitation (M-and-R needs as well as ensure that road maintenance budgets are spent wisely. In this research, the pavement condition was evaluated in terms of the surface distresses existing at the time of the field evaluation. The PCI procedure was used in this research because it deals with the subject of pavement distress identification most comprehensively and is based on a sound statistical technique of pavement sampling.

  1. Remediation of Gremikha Coastal maintenance base - status of the project

    International Nuclear Information System (INIS)

    Pillette-Cousin, L.; Stepennov, B.S.; Gorbatchev, A.

    2008-01-01

    The former coastal maintenance base in Gremikha is located in the Kola Peninsula, along the Barents Sea, about 300 km east from Murmansk. There is no road or railway to get there, therefore the only possible connection is either by sea or by helicopter. Remediation of the Gremikha coastal maintenance base (CMB) is now one of the main priorities for Rosatom (the Agency for Atomic Energy of the Russian Federation) because nuclear and radioactive waste are currently stored in conditions which do not meet the up-to-date safety and regulatory requirements and it might represent an environmental hazard and a risk of misappropriation of the nuclear material stored there. (authors)

  2. Reliability-based maintenance evaluations and standard preventive maintenance programs

    International Nuclear Information System (INIS)

    Varno, M.; McKinley, M.

    1993-01-01

    Due to recent issuance of 10CFR50.65, the U.S. Nuclear Regulatory Commission maintenance rule (Rule), and the open-quotes Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plantsclose quotes prepared by the Nuclear Management and Resources Council, many utilities are undertaking review or evaluation of current preventive maintenance (PM) programs. Although PM optimization and documentation are not specifically required by the Rule, an appropriate and effective PM program (PMP) will be the cornerstone of the successful and cost-effective implementation of the Rule. Currently, a project is being conducted at the Vermont Yankee Nuclear Power Station (VYNPS) in conjunction with Quadrex Energy Services to evaluate, optimize, and document the PMP. The project began in March 1993 and is scheduled for completion in mid-1995. The initial scope for the project is the evaluation of those structures, systems, and components that are within the scope of the Rule. Because of the number of systems to be evaluated (∼50), the desired completion schedule, and cost considerations, a streamlined approach to PM optimization and documentation is being utilized

  3. Maintenance Staffing Standards for Zero-Based Budgeting.

    Science.gov (United States)

    Adams, Matthew C.; And Others

    1998-01-01

    Discusses school preventive maintenance and the variables associated with maintenance staffing standards that address a zero-based budgeting environment. Explores preventive-maintenance measurement for staffing requirements, defines staffing levels and job descriptions, and outlines the factors to consider when creating a maintenance program and…

  4. Cost savings from performance-based maintenance contracting

    NARCIS (Netherlands)

    Straub, A.

    2009-01-01

    New procurement approaches combined with performance-based building approaches should reduce costs, but empirical qualitative and quantitative studies are lacking. Performance-based maintenance contracts give maintenance suppliers incentives to improve their way of working. Innovative,

  5. Development the conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation

    Science.gov (United States)

    Milana; Khan, M. K.; Munive, J. E.

    2014-07-01

    The importance of maintenance has escalated significantly by the increasing of automation in manufacturing process. This condition switches traditional maintenance perspective of inevitable cost into the business competitive driver. Consequently, maintenance strategy and operation decision needs to be synchronized to business and manufacturing concerns. This paper shows the development of conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation (KBIMSO). The framework of KBIMSO is elaborated to show the process of how the KBIMSO works to reach the maintenance decision. By considering the multi-criteria of maintenance decision making, the KB system embedded with GAP and AHP to support integrated maintenance strategy and operation which is novel in this area. The KBIMSO is useful to review the existing maintenance system and give reasonable recommendation of maintenance decisions in respect to business and manufacturing perspective.

  6. Development the conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation

    International Nuclear Information System (INIS)

    Milana; Khan, M K; Munive, J E

    2014-01-01

    The importance of maintenance has escalated significantly by the increasing of automation in manufacturing process. This condition switches traditional maintenance perspective of inevitable cost into the business competitive driver. Consequently, maintenance strategy and operation decision needs to be synchronized to business and manufacturing concerns. This paper shows the development of conceptual design of Knowledge Based System for Integrated Maintenance Strategy and Operation (KBIMSO). The framework of KBIMSO is elaborated to show the process of how the KBIMSO works to reach the maintenance decision. By considering the multi-criteria of maintenance decision making, the KB system embedded with GAP and AHP to support integrated maintenance strategy and operation which is novel in this area. The KBIMSO is useful to review the existing maintenance system and give reasonable recommendation of maintenance decisions in respect to business and manufacturing perspective

  7. Equipment Maintenance management support system based on statistical analysis of maintenance history data

    International Nuclear Information System (INIS)

    Shimizu, S.; Ando, Y.; Morioka, T.

    1990-01-01

    Plant maintenance is recently becoming important with the increase in the number of nuclear power stations and in plant operating time. Various kinds of requirements for plant maintenance, such as countermeasures for equipment degradation and saving maintenance costs while keeping up plant reliability and productivity, are proposed. For this purpose, plant maintenance programs should be improved based on equipment reliability estimated by field data. In order to meet these requirements, it is planned to develop an equipment maintenance management support system for nuclear power plants based on statistical analysis of equipment maintenance history data. The large difference between this proposed new method and current similar methods is to evaluate not only failure data but maintenance data, which includes normal termination data and some degree of degradation or functional disorder data for equipment and parts. So, it is possible to utilize these field data for improving maintenance schedules and to evaluate actual equipment and parts reliability under the current maintenance schedule. In the present paper, the authors show the objectives of this system, an outline of this system and its functions, and the basic technique for collecting and managing of maintenance history data on statistical analysis. It is shown, from the results of feasibility tests using simulation data of maintenance history, that this system has the ability to provide useful information for maintenance and the design enhancement

  8. Maintenance Decision Based on Data Fusion of Aero Engines

    Directory of Open Access Journals (Sweden)

    Huawei Wang

    2013-01-01

    Full Text Available Maintenance has gained a great importance as a support function for ensuring aero engine reliability and availability. Cost-effectiveness and risk control are two basic criteria for accurate maintenance. Given that aero engines have much condition monitoring data, this paper presents a new condition-based maintenance decision system that employs data fusion for improving accuracy of reliability evaluation. Bayesian linear model has been applied, so that the performance degradation evaluation of aero engines could be realized. A reliability evaluation model has been presented based on gamma process, which achieves the accurate evaluation by information fusion. In reliability evaluation model, the shape parameter is estimated by the performance degradation evaluation result, and the scale parameter is estimated by failure, inspection, and repair information. What is more, with such reliability evaluation as input variables and by using particle swarm optimization (PSO, a stochastic optimization of maintenance decision for aircraft engines has been presented, in which the effectiveness and the accuracy are demonstrated by a numerical example.

  9. Virtual maintenance technology for reactor system based on PPR technology

    International Nuclear Information System (INIS)

    Wu Yaxiang; Ma Baiyong

    2009-01-01

    Based on the Product, Process and Resources (PPR) technology, the establishing technology of virtual maintenance environment for the reactor system and the process structure tree for virtual maintenance is studied, and the flow for the maintainability design and simulation for reactor system is put forward. Based on the subsection simulation of maintenance process and layered design of maintenance actions, the leveled structure of the reactor system virtual maintenance task is studied. The relation for the data of product, process and resource is described by Plan Evaluation and Review Technology (PERT) diagram to define the maintenance operation. (authors)

  10. Structuring AHP-based maintenance policy selection

    NARCIS (Netherlands)

    Goossens, Adriaan; Basten, Robertus Johannes Ida; Hummel, J. Marjan; van der Wegen, Leonardus L.M.

    2015-01-01

    We aim to structure the maintenance policy selection process for ships, using the Analytic Hierarchy Process (AHP). Maintenance is an important contributor to reach the intended life-time of capital technical assets, and it is gaining increasing interest and relevance. A maintenance policy is a

  11. A COMPUTER BASED MAINTENANCE MANAGEMENT SYSTEM ...

    African Journals Online (AJOL)

    ... programs to schedule for maintenance or replacement of machines has been designed such that it enables the maintenance department control all jobs associated with plant maintenance and breakdown. It predicts the time to failure of designated plants and caters for the replacement analysis of some capital equipment.

  12. Maintenance management sourcing strategies and the condition of ...

    African Journals Online (AJOL)

    In the face of the deplorable state of buildings across the various tertiary institutions in Nigeria, the need to deploy appropriate maintenance management strategy cannot be overemphasized. However, sourcing decision for maintenance services remains a tough one for decision makers as different sourcing option suit ...

  13. Age-dependent reliability model considering effects of maintenance and working conditions

    International Nuclear Information System (INIS)

    Martorell, Sebastian; Sanchez, Ana; Serradell, Vicente

    1999-01-01

    Nowadays, there is some doubt about building new nuclear power plants (NPPs). Instead, there is a growing interest in analyzing the possibility to extend current NPP operation, where life management programs play an important role. The evolution of the NPP safety depends on the evolution of the reliability of its safety components, which, in turn, is a function of their age along the NPP operational life. In this paper, a new age-dependent reliability model is presented, which includes parameters related to surveillance and maintenance effectiveness and working conditions of the equipment, both environmental and operational. This model may be used to support NPP life management and life extension programs, by improving or optimizing surveillance and maintenance tasks using risk and cost models based on such an age-dependent reliability model. The results of the sensitivity study in the example application show that the selection of the most appropriate maintenance strategy would directly depend on the previous parameters. Then, very important differences are expected to appear under certain circumstances, particularly, in comparison with other models that do not consider maintenance effectiveness and working conditions simultaneously

  14. Component-Based Data-Driven Predictive Maintenance to Reduce Unscheduled Maintenance Events

    NARCIS (Netherlands)

    Verhagen, W.J.C.; Curran, R.; de Boer, L.W.M.; Chen, C.H.; Trappey, A.C.; Peruzzini, M.; Stjepandić, J.; Wognum, N.

    2017-01-01

    Costs associated with unscheduled and preventive maintenance can contribute significantly to an airline's expenditure. Reliability analysis can help to identify and plan for maintenance events. Reliability analysis in industry is often limited to statistically based

  15. A Real-Time Quantitative Condition Alerting and Analysis Support System for Aircraft Maintenance, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Financial constraints, government recommendations, and the need for improved operational efficiency are requiring airlines to review their "on-condition" maintenance...

  16. Performance based regulation - The maintenance rule

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Richard P. [NRR/DOTS/TQMP, U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, M/S OWFN 10A19, Washington, D.C. 20555 (United States)

    1997-07-01

    The U.S. Nuclear Regulatory Commission has begun a transition from 'process-oriented' to 'results-oriented' regulations. The maintenance rule is a results-oriented rule that mandates consideration of risk and plant performance. The Maintenance Rule allows licensees to devise the most effective and efficient means of achieving the results described in the rule including the use of Probabilistic Risk (or Safety) Assessments. The NRC staff conducted a series of site visits to evaluate implementation of the Rule. Conclusions from the site visits indicated that the results-oriented Maintenance Rule can be successfully implemented and enforced. (author)

  17. Performance based regulation - The maintenance rule

    International Nuclear Information System (INIS)

    Correia, Richard P.

    1997-01-01

    The U.S. Nuclear Regulatory Commission has begun a transition from 'process-oriented' to 'results-oriented' regulations. The maintenance rule is a results-oriented rule that mandates consideration of risk and plant performance. The Maintenance Rule allows licensees to devise the most effective and efficient means of achieving the results described in the rule including the use of Probabilistic Risk (or Safety) Assessments. The NRC staff conducted a series of site visits to evaluate implementation of the Rule. Conclusions from the site visits indicated that the results-oriented Maintenance Rule can be successfully implemented and enforced. (author)

  18. Pavement condition assessment to forecast maintenance program on JKR state roads in Petaling district

    Science.gov (United States)

    Hamsan, R.; Hafiz, H.; Azlan, A.; Keprawi, M. F.; Malik, A. K. A.; Adamuddin, A.; Abdullah, A. H.; Shafie, A. M.

    2018-02-01

    This research allows local authorities to project road maintenance in term of activities and financial expenditure through pavement condition assessment and then Highway Development and Management (HDM-4) analysis. Current form of road maintenance carried out by local authority is on reactive manner where corrective actions were taken based on reports recorded. Some went unrecorded hence causing prolonged damages. This causes the local authority unable to project the required cost to maintain the roads. This affects the socio-economy of the surrounding routes. Hence, it is seen, as preventive maintenance of the roads will provide more feasible option in term of work force and finance to the local authority. To overcome this issue, a preventive model was introduced. This was done through pavement condition assessment (PCA) where analysis was done through HDM-4. Nondestructive test and destructive test were conducted in order to provide an indicator to the road's health. This were then analyzed in HDM-4 where the result was benchmarked with maintenance standard. The scope of this research is set to PCA where DT and NDT were performed on the routes of Petaling and the output is analyzed in HDM-4. The result of this research provides a 10 years forecast maintenance budget in maintaining the roads in Petaling. This allows the local authority to perform good practice in term of maintaining the roads while at the same time helps them in forecasting their budget for the upcoming years. This research will have a strong impact on the local socio-economy as well as local road user confidence towards the authority over good practices. This research can be further expanded to other type of roads as well as highway bridges.

  19. Health and safety conditions of building maintenance sites in Nigeria

    African Journals Online (AJOL)

    To identify the microorganisms, bulk samples were collected on timber buildings classified as maintenance sites over the country and then identify the microorganisms available using the cultivation technique. Eight hundred and fifty nutrient and Sabouraud dextrose agar dishes were prepared. The nutrient agar dishes were ...

  20. Performance-based maintenance of gas turbines for reliable control of degraded power systems

    Science.gov (United States)

    Mo, Huadong; Sansavini, Giovanni; Xie, Min

    2018-03-01

    Maintenance actions are necessary for ensuring proper operations of control systems under component degradation. However, current condition-based maintenance (CBM) models based on component health indices are not suitable for degraded control systems. Indeed, failures of control systems are only determined by the controller outputs, and the feedback mechanism compensates the control performance loss caused by the component deterioration. Thus, control systems may still operate normally even if the component health indices exceed failure thresholds. This work investigates the CBM model of control systems and employs the reduced control performance as a direct degradation measure for deciding maintenance activities. The reduced control performance depends on the underlying component degradation modelled as a Wiener process and the feedback mechanism. To this aim, the controller features are quantified by developing a dynamic and stochastic control block diagram-based simulation model, consisting of the degraded components and the control mechanism. At each inspection, the system receives a maintenance action if the control performance deterioration exceeds its preventive-maintenance or failure thresholds. Inspired by realistic cases, the component degradation model considers random start time and unit-to-unit variability. The cost analysis of maintenance model is conducted via Monte Carlo simulation. Optimal maintenance strategies are investigated to minimize the expected maintenance costs, which is a direct consequence of the control performance. The proposed framework is able to design preventive maintenance actions on a gas power plant, to ensuring required load frequency control performance against a sudden load increase. The optimization results identify the trade-off between system downtime and maintenance costs as a function of preventive maintenance thresholds and inspection frequency. Finally, the control performance-based maintenance model can reduce

  1. Information-Based Maintenance Optimization with Focus on Predictive Maintenance (Informatiegebaseerde onderhoudsoptimalisatie met focus op predictief onderhoud)

    OpenAIRE

    Van Horenbeek, Adriaan

    2013-01-01

    This dissertation presents an information-based maintenance optimization methodology for physical assets; with focus on, but not limited to, predictive maintenance (PdM). The overall concept of information-based maintenance is that of updating maintenance decisions based on evolving knowledge of operation history and anticipated usage of the machinery, as well as the physics and dynamics of material degradation in critical machinery components. Within this concept, predictive maintenance is a...

  2. Imperfect Preventive Maintenance Model Study Based On Reliability Limitation

    Directory of Open Access Journals (Sweden)

    Zhou Qian

    2016-01-01

    Full Text Available Effective maintenance is crucial for equipment performance in industry. Imperfect maintenance conform to actual failure process. Taking the dynamic preventive maintenance cost into account, the preventive maintenance model was constructed by using age reduction factor. The model regards the minimization of repair cost rate as final target. It use allowed smallest reliability as the replacement condition. Equipment life was assumed to follow two parameters Weibull distribution since it was one of the most commonly adopted distributions to fit cumulative failure problems. Eventually the example verifies the rationality and benefits of the model.

  3. Risk-based and maintenance systems for steam turbines

    International Nuclear Information System (INIS)

    Fujiyama, K.; Nagai, S.; Akikuni, Y.; Fujiwara, T.; Furuya, K.; Matsumoto, S.; Takagi, K.; Kawabata, T.

    2003-01-01

    The risk-based maintenance (RBM) system has been developed for steam turbine plants coupled with the quick inspection systems. The RBM system utilizes the field failure and inspection database accumulated over 30 years. The failure modes are determined for each component of steam turbines and the failure scenarios are described as event trees. The probability of failure is expressed in the form of unreliability functions of operation hours or start-up cycles through the cumulative hazard function method. The posterior unreliability is derived from the field data analysis according to the inspection information. Quick inspection can be conducted using air-cooled borescope and heat resistant ultrasonic sensors even if the turbine is not cooled down sufficiently. Another inspection information comes from degradation and damage measurement. The probabilistic life assessment using structural analysis and statistical material properties, the latter is estimated from hardness measurement, replica observation and embrittlement measurement. The risk function is calculated as the sum product of unreliability functions and expected monetary loss as the consequence of failure along event trees. The optimum maintenance plan is determined among simulated scenarios described through component breakdown trees, life cycle event trees and risk functions. Those methods are effective for total condition assessment and economical maintenance for operating plants. (orig.)

  4. Risk-based inspection and maintenance systems for steam turbines

    International Nuclear Information System (INIS)

    Fujiyama, Kazunari; Nagai, Satoshi; Akikuni, Yasunari; Fujiwara, Toshihiro; Furuya, Kenichiro; Matsumoto, Shigeru; Takagi, Kentaro; Kawabata, Taro

    2004-01-01

    The risk-based maintenance (RBM) system has been developed for steam turbine plants coupled with the quick inspection systems. The RBM system utilizes the field failure and inspection database accumulated over 30 years. The failure modes are determined for each component of steam turbines and the failure scenarios are described as event trees. The probability of failure is expressed in the form of unreliability functions of operation hours or start-up cycles through the cumulative hazard function method. The posterior unreliability is derived from the field data analysis according to the inspection information. Quick inspection can be conducted using air-cooled borescope and heat resistant ultrasonic sensors even if the turbine is not cooled down sufficiently. Another inspection information comes from degradation and damage measurement. The probabilistic life assessment using structural analysis and statistical material properties, the latter is estimated from hardness measurement, replica observation and embrittlement measurement. The risk function is calculated as the sum product of unreliability functions and expected monetary loss as the consequence of failure along event trees. The optimum maintenance plan is determined among simulated scenarios described through component breakdown trees, life cycle event trees and risk functions. Those methods are effective for total condition assessment and economical maintenance for operating plants

  5. Risk-Based Operation and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2009-01-01

    For offshore wind turbines costs to operation and maintenance are substantial. This paper describes a risk-based lifecycle approach for optimal planning of operation and maintenance. The approach is based on pre-posterior Bayesian decision theory. Deterioration mechanisms such as fatigue, corrosion...

  6. Optimization of maintenance programme at Daya Bay Nuclear Power Station based on RCM analysis results

    International Nuclear Information System (INIS)

    Liu Min

    2003-01-01

    This paper begins with an introduction to Guangdong Daya Bay Nuclear Power Station (GNPS) and gives a simple introduction to the operations and maintenance documentation system at GNPS. It then will review the maintenance program guidelines base and the associated problems prior to the application of reliability centered maintenance (RCM). How RCM was implemented at GNPS, how the results of RCM analysis were used to optimize the maintenance program and test program, and what is the interface between RCM and the existing maintenance program will be shown. Next, it will show the successful implementation of RCM at GNPS resulted in the following changes: A new understanding of equipment failure challenges operations and maintenance beliefs, maintenance concepts undergo a large change, maintenance program and periodic testing program are continuously modified and optimized, new on-condition maintenance technologies are introduced, non-productive scheduled overhauls are discarded, maintenance costs are effectively controlled, maintenance appropriateness has improved, management of hidden failures is more effective and timely. It will show the benefit of greater equipment reliability brought about by all of these changes, which in turn increases the reliability and safety of the entire power station. (author)

  7. Sensitivity of Risk-Based Maintenance Planning of Offshore Wind Turbine Farms

    DEFF Research Database (Denmark)

    Ambühl, Simon; Sørensen, John Dalsgaard

    2017-01-01

    Inspection and maintenance expenses cover a considerable part of the cost of energy from offshore wind turbines. Risk-based maintenance planning approaches are a powerful tool to optimize maintenance and inspection actions and decrease the total maintenance expenses. Risk-based planning is based...... on many input parameters, which are in reality often not completely known. This paper will assess the cost impact of this incomplete knowledge based on a case study following risk-based maintenance planning. The sensitivity study focuses on weather forecast uncertainties, incomplete knowledge about...... the needed repair time on the site as well as uncertainties about the operational range of the boat and helicopter used to access the broken wind turbine. The cost saving potential is estimated by running Crude Monte Carlo simulations. Furthermore, corrective and preventive (scheduled and condition...

  8. Risk-Based Operation and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nielsen, Jannie Sønderkær

    For offshore wind turbines, maintenance costs are substantial due to a large number of component failures. In addition to the repair costs, equipment costs and lost production costs are large due to limited accessibility to the turbines. In order to reduce the costs, preventive methods can be used......, but presently maintenance is not planned using advanced methods taking all available information into account in a consistent manner. Maintenance decisions can be made based on risk-based methods, where the total expected life cycle costs are minimized. Methods have been developed for assessing the corrective...... maintenance costs, and many studies have also been published for preventive maintenance. However, an important part is the modeling of the relationship between maintenance and reliability, which is typically not modeled in a consistent way. Therefore, the methods cannot be used directly for optimal...

  9. Control-limit preventive maintenance policies for components subject to imperfect preventive maintenance and variable operational conditions

    International Nuclear Information System (INIS)

    You Mingyi; Li Hongguang; Meng Guang

    2011-01-01

    This paper develops two component-level control-limit preventive maintenance (PM) policies for systems subject to the joint effect of partial recovery PM acts (imperfect PM acts) and variable operational conditions, and investigates the properties of the proposed policies. The extended proportional hazards model (EPHM) is used to model the system failure likelihood influenced by both factors. Several numerical experiments are conducted for policy property analysis, using real lifetime and operational condition data and typical characterization of imperfect PM acts and maintenance durations. The experimental results demonstrate the necessity of considering both factors when they do exist, characterize the joint effect of the two factors on the performance of an optimized PM policy, and explore the influence of the loading sequence of time-varying operational conditions on the performance of an optimized PM policy. The proposed policies extend the applicability of PM optimization techniques.

  10. Optimizing block-based maintenance under random machine usage

    NARCIS (Netherlands)

    de Jonge, Bram; Jakobsons, Edgars

    Existing studies on maintenance optimization generally assume that machines are either used continuously, or that times until failure do not depend on the actual usage. In practice, however, these assumptions are often not realistic. In this paper, we consider block-based maintenance optimization

  11. Model based decision support for planning of road maintenance

    NARCIS (Netherlands)

    van Harten, Aart; Worm, J.M.; Worm, J.M.

    1996-01-01

    In this article we describe a Decision Support Model, based on Operational Research methods, for the multi-period planning of maintenance of bituminous pavements. This model is a tool for the road manager to assist in generating an optimal maintenance plan for a road. Optimal means: minimising the

  12. A knowledge-based assistant for valve maintenance planning

    International Nuclear Information System (INIS)

    Winter, M.J.; Danofsky, R.A.; Spinrad, B.I.; Howard, K.

    1987-01-01

    A knowledge-based program is being developed to assist engineers in maintenance planning for safety related, motor-operated valves at a boiling water reactor. The purpose of this project is to develop the general framework for a prototype system that demonstrates the capabilities for diagnosing valve symptoms and prescribing corrective maintenance, completing a portion of the Corrective Maintenance Action Request (CMAR) form which must be prepared for each job, and managing an interactive valve data base. Minimizing user input and providing output in a form that is familiar to the maintenance planning engineer are important goals for the program. This paper describes the present features of the valve maintenance advisory system which is currently being tested

  13. Risk-based maintenance-Techniques and applications

    International Nuclear Information System (INIS)

    Arunraj, N.S.; Maiti, J.

    2007-01-01

    Plant and equipment, however well designed, will not remain safe or reliable if it is not maintained. The general objective of the maintenance process is to make use of the knowledge of failures and accidents to achieve the possible safety with the lowest possible cost. The concept of risk-based maintenance was developed to inspect the high-risk components usually with greater frequency and thoroughness and to maintain in a greater manner, to achieve tolerable risk criteria. Risk-based maintenance methodology provides a tool for maintenance planning and decision making to reduce the probability of failure of equipment and the consequences of failure. In this paper, the risk analysis and risk-based maintenance methodologies were identified and classified into suitable classes. The factors affecting the quality of risk analysis were identified and analyzed. The applications, input data and output data were studied to understand their functioning and efficiency. The review showed that there is no unique way to perform risk analysis and risk-based maintenance. The use of suitable techniques and methodologies, careful investigation during the risk analysis phase, and its detailed and structured results are necessary to make proper risk-based maintenance decisions

  14. The Issues of Track Maintenance Management in Indonesia (Based on Study of the British Railways

    Directory of Open Access Journals (Sweden)

    Tetria Yunik Dewi Pamungkas

    2017-01-01

    Full Text Available It is believed that there is merit in researching how the management of track maintenance is organized in the United Kingdom, in particular by Network Rail, and then evaluating how this can be applied to the benefit of Indonesian Railways. The purpose of this research was expected to provide recommendations for management improvement of track maintenance by researching the track maintenance management system in Network Rail. This research study is based on secondary data. The analysis was conducted by using comparison method which compares the British Railways management and Indonesia railway management related to track maintenance management. The track maintenance management system was studied by using Network Rail. The results were compared with track maintenance management system in Indonesia. The comparison will provide the data differences that evaluated so the problem can be identified. The final result of this analysis was the identification of problems and improvisation that can be done for the development of track maintenance management in Indonesia. Several management issues have been mapped to several groups: finance management, structure organization, and asset management. From the problems that have been mapped, some improvements are recommended as monopolist authority restriction, maintenance system contract extension, re-structuring organization hierarchy, business plan consideration, track monitoring strategy arrangement, and condition based maintenance strategy adoption.

  15. Design and evaluation of augmented reality for nuclear power plant maintenance based on Cognitive activity analysis

    International Nuclear Information System (INIS)

    Koo, Jwa Jin

    2008-02-01

    The goals of maintenance in nuclear power plants (NPPs) are to reduce the number of plant shutdowns, to decrease the shutdown time, to minimize the maintenance costs, and to improve nuclear safety. Furthermore, it is difficult for maintenance personnel to conduct work in NPPs due to the complexity of NPPs, safety issues and time constraints. Human errors should be prevented to achieve maintenance goals in NPPs. Therefore, it is necessary to improve working conditions by introducing support systems. Augmented Reality (AR) has the potential to assist with maintenance tasks and make maintenance personnel concentrate on the tasks, which will then the reduced human error and improve human performance. The working procedure for AR systems was designed based on the characteristics of cognitive activity, and an experiment was conducted to estimate the effectiveness of AR. The results indicated that a well-designed working procedure for AR systems was more effective than a conventional paper-based working procedure. In addition, participants made fewer errors using the designed working procedure. AR systems as maintenance support systems are beneficial technology that can improve maintenance performance by reducing cognitive loads and unnecessary movements. An AR application can be attractive and effective at supporting maintenance task

  16. Reliability-based performance simulation for optimized pavement maintenance

    International Nuclear Information System (INIS)

    Chou, Jui-Sheng; Le, Thanh-Son

    2011-01-01

    Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: →A novel algorithm using multi-objective particle swarm optimization technique. → Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. → A probabilistic model for regression parameters is employed to assess reliability-based performance. → The proposed approach can help decision makers to optimize roadway maintenance plans.

  17. Reliability-based performance simulation for optimized pavement maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Jui-Sheng, E-mail: jschou@mail.ntust.edu.tw [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China); Le, Thanh-Son [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China)

    2011-10-15

    Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: > A novel algorithm using multi-objective particle swarm optimization technique. > Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. > A probabilistic model for regression parameters is employed to assess reliability-based performance. > The proposed approach can help decision makers to optimize roadway maintenance plans.

  18. A Novel Short-Term Maintenance Strategy for Power Transmission and Transformation Equipment Based on Risk-Cost-Analysis

    Directory of Open Access Journals (Sweden)

    Hang Yang

    2017-11-01

    Full Text Available Current studies on preventive condition-based maintenance of power transmission and transformation equipment mainly focus on mid-term or long-term maintenance, and cannot meet the requirements of short-term especially temporary maintenance. In order to solve the defects of the present preventive maintenance strategies, according to the engineering application and based on risk-cost analysis, a short-term maintenance strategy is proposed in this manuscript. For the equipment working in bad health condition, its active maintenance costs and operation risk costs are evaluated, respectively. Then the latest maintenance time is calculated in accordance with the principle that its operation risk costs are no higher than active maintenance costs. Utilizing the latest maintenance time, the best maintenance time is calculated by setting the maximum relative earnings of postponing maintenance as the target, which provides the operation staffs with comprehensive maintenance-decision support. In the end, different cases on the IEEE 24-bus system are simulated. The effectiveness and advantages of the proposed strategy are demonstrated by the simulation results.

  19. A reliability program for emergency diesel generators at nuclear power plants: Maintenance, surveillance, and condition monitoring

    International Nuclear Information System (INIS)

    Lofgren, E.V.; Henderson, W.; Burghardt, D.; Kripps, L.; Rothleder, B.

    1988-12-01

    This report is a companion report on NUREG/CR-5078, Volume 1, ''A Reliability Program for Emergency Diesel Generators at Nuclear Power Plants: Program Structure.'' The purpose of this report is to provide technical findings and insights related to: failure evaluation, troubleshooting, maintenance, surveillance, and condition monitoring. Examples and recommendations are provided for each of these areas based on actual emergency diesel generator (EDG) operating experience and the opinions of diesel generator experts. This report expands the more general guidance provided in Volume 1. In addition, a discussion of EDG interactions with other plant systems (e.g., instrument, air, service water, dc power) is provided since experience has shown that these support systems and their operation can adversely affect EDG reliability. Portions of this report have been designed for use by onsite personnel for evaluating operational characteristics of EDGs. 5 refs., 8 figs., 7 tabs

  20. Reliability analysis and risk-based methods for planning of operation & maintenance of offshore wind turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2017-01-01

    for extreme and fatigue limit states are presented. Operation & Maintenance planning often follows corrective and preventive strategies based on information from condition monitoring and structural health monitoring systems. A reliability- and risk-based approach is presented where a life-cycle approach...

  1. Aging based maintenance and reinvestment scheduling of electric distribution

    Energy Technology Data Exchange (ETDEWEB)

    Korpijarvi, J.

    2012-07-01

    The maintenance of electric distribution network is a topical question for distribution system operators because of increasing significance of failure costs. In this dissertation the maintenance practices of the distribution system operators are analyzed and a theory for scheduling maintenance activities and reinvestment of distribution components is created. The scheduling is based on the deterioration of components and the increasing failure rates due to aging. The dynamic programming algorithm is used as a solving method to maintenance problem which is caused by the increasing failure rates of the network. The other impacts of network maintenance like environmental and regulation reasons are not included to the scope of this thesis. Further the tree trimming of the corridors and the major disturbance of the network are not included to the problem optimized in this thesis. For optimizing, four dynamic programming models are presented and the models are tested. Programming is made in VBA-language to the computer. For testing two different kinds of test networks are used. Because electric distribution system operators want to operate with bigger component groups, optimal timing for component groups is also analyzed. A maintenance software package is created to apply the presented theories in practice. An overview of the program is presented (orig.)

  2. The International Coal Statistics Data Base program maintenance guide

    International Nuclear Information System (INIS)

    1991-06-01

    The International Coal Statistics Data Base (ICSD) is a microcomputer-based system which contains information related to international coal trade. This includes coal production, consumption, imports and exports information. The ICSD is a secondary data base, meaning that information contained therein is derived entirely from other primary sources. It uses dBase III+ and Lotus 1-2-3 to locate, report and display data. The system is used for analysis in preparing the Annual Prospects for World Coal Trade (DOE/EIA-0363) publication. The ICSD system is menu driven and also permits the user who is familiar with dBase and Lotus operations to leave the menu structure to perform independent queries. Documentation for the ICSD consists of three manuals -- the User's Guide, the Operations Manual, and the Program Maintenance Manual. This Program Maintenance Manual provides the information necessary to maintain and update the ICSD system. Two major types of program maintenance documentation are presented in this manual. The first is the source code for the dBase III+ routines and related non-dBase programs used in operating the ICSD. The second is listings of the major component database field structures. A third important consideration for dBase programming, the structure of index files, is presented in the listing of source code for the index maintenance program. 1 fig

  3. Optimizing preventive maintenance with maintenance templates

    International Nuclear Information System (INIS)

    Dozier, I.J.

    1996-01-01

    Rising operating costs has caused maintenance professionals to rethink their strategy for preventive maintenance (PM) programs. Maintenance Templates are pre-engineered PM task recommendations for a component type based on application of the component. Development of the maintenance template considers the dominant failure cause of the component and the type of preventive maintenance that can predict or prevent the failure from occurring. Maintenance template development also attempts to replace fixed frequency tasks with condition monitoring tasks such as vibration analysis or thermography. For those components that have fixed frequency PM intervals, consideration is given to the maintenance drivers such as criticality, environment and usage. This helps to maximize the PM frequency intervals and maximize the component availability. Maintenance Templates have been used at PECO Energy's Limerick Generating Station during the Reliability Centered Maintenance (RCM) Process to optimize their PM program. This paper describes the development and uses of the maintenance templates

  4. Risk-Based Operation and Maintenance Planning for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2010-01-01

    Operation and maintenance (O&M) are large contributors to the cost of energy for offshore wind turbines. Optimal planning of O&M should include use of inspections and monitoring results to make decisions that minimize the expected costs through the lifetime of the structures. For offshore...... structures it is especially important because of the dependence on weather windows for inspections and repairs to be possible. A model has been developed to estimate the expected costs to corrective and condition based maintenance for a wind turbine with a single component. The deterioration of the component...... is simulated, and the expected costs are found for different strategies. An application example shows that condition based maintenance has the potential of reducing the costs, and a risk based approach can be used to find the optimal strategy for O&M. Further the influence of failure rate and damage parameters...

  5. Psychological Conditions of Engagement among Community College Maintenance Employees: A Cross-Sectional Study

    Science.gov (United States)

    Franks, Tammy T.

    2017-01-01

    This dissertation examined the relationship between employee engagement and the factors that may influence the three psychological conditions of engagement: meaningfulness, safety, and availability for the sector of employees classified as maintenance, grounds, and custodial employees in a community college setting. The factors for each of the…

  6. Pedagogical conditions of maintenance of integrity of process of socialization-individualization of children-orphans

    OpenAIRE

    Pronina A. N.

    2011-01-01

    Formation of the high-grade person of children of preschool age, without parental support should be carried out in complete process of socialization-individualization that assumes working out of the pedagogical conditions directed on maintenance of interrelation of processes of socialization and an individualization.

  7. Risk Based Maintenance of Offshore Wind Turbines Using Bayesian Networks

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2010-01-01

    This paper presents how Bayesian networks can be used to make optimal decisions for repairs of offshore wind turbines. The Bayesian network is an efficient tool for updating a deterioration model whenever new information becomes available from inspections/monitoring. The optimal decision is found...... such that the preventive maintenance effort is balanced against the costs to corrective maintenance including indirect costs to reduced production. The basis for the optimization is the risk based Bayesian decision theory. The method is demonstrated through an application example....

  8. Methadone maintenance therapy as evidence based drug abuse ...

    African Journals Online (AJOL)

    Methadone maintenance therapy as evidence based drug abuse planning in ... drugs are being used as artificial problem-solvers such as frustrations, stress or ... Drug use is a problem to users when it begins to cause some damage to their ...

  9. Performance-based maintenance procurement by Dutch housing associations

    NARCIS (Netherlands)

    Straub, A.

    2004-01-01

    OTB Research institute has established a long-term research program to performance-based maintenance procurement in the technical management of housing stock. Stakeholders: housing associations, contractors and the Dutch Building Research Foundation are directly involved in this research program.

  10. Risk-Based Operation and Maintenance Using Bayesian Networks

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2011-01-01

    This paper describes how risk-based decision making can be used for maintenance planning of components exposed to degradation such as fatigue in offshore wind turbines. In fatigue models, large epistemic uncertainties are usually present. These can be reduced if monitoring results are used to upd...

  11. Planning of operation & maintenance using risk and reliability based methods

    DEFF Research Database (Denmark)

    Florian, Mihai; Sørensen, John Dalsgaard

    2015-01-01

    Operation and maintenance (OM) of offshore wind turbines contributes with a substantial part of the total levelized cost of energy (LCOE). The objective of this paper is to present an application of risk- and reliability-based methods for planning of OM. The theoretical basis is presented...

  12. Maintenance management of railway infrastructures based on reliability analysis

    International Nuclear Information System (INIS)

    Macchi, Marco; Garetti, Marco; Centrone, Domenico; Fumagalli, Luca; Piero Pavirani, Gian

    2012-01-01

    Railway infrastructure maintenance plays a crucial role for rail transport. It aims at guaranteeing safety of operations and availability of railway tracks and related equipment for traffic regulation. Moreover, it is one major cost for rail transport operations. Thus, the increased competition in traffic market is asking for maintenance improvement, aiming at the reduction of maintenance expenditures while keeping the safety of operations. This issue is addressed by the methodology presented in the paper. The first step of the methodology consists of a family-based approach for the equipment reliability analysis; its purpose is the identification of families of railway items which can be given the same reliability targets. The second step builds the reliability model of the railway system for identifying the most critical items, given a required service level for the transportation system. The two methods have been implemented and tested in practical case studies, in the context of Rete Ferroviaria Italiana, the Italian public limited company for railway transportation.

  13. Prioritization of pavement maintenance sections using objective based Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Sarfaraz Ahmed

    2017-03-01

    Full Text Available The application of Analytic Hierarchy Process (AHP method for the prioritization of pavement maintenance sections is widespread now-a-days. Although the evaluation of pavement maintenance section through AHP method is simple, where the relative importance (on Saaty’s scale assigned to each parameter in the hierarchy varies between the experts (transportation professionals consulted, which leads to discrepancies in the final rankings of the sections’, due to the subjectivity in the process. Further, experts base their decisions solely on their experience while consideration is not given to the actual quantitative physical condition of the roads. To overcome these difficulties an objective based AHP method is proposed in this study, where pairwise comparison values are assigned based on the collected field data from a road network in Mumbai city, consisting of 28 road sections. The final ranking list of candidate sections takes into consideration the priority weight of alternatives, which reflect the road conditions. The solution of priority ratings of AHP method is compared with the corresponding solution of road condition index method, a traditional pavement maintenance procedure. The findings of the present study suggest that objective based AHP method is more suitable for the prioritization of pavement maintenance of roads. Keywords: Prioritization, Analytic Hierarchy Process, Road condition index, Objective method, Rating and ranking

  14. Reliability and risk-based planning of operation and maintenance of offshore wind turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Florian, Mihai; Berzonskis, Arvydas

    2016-01-01

    costly (and safe), and it is important to include in the reliability assessment the information obtained during operation (from condition monitoring and inspections) and the maintenance performed (incl. repairs and replacements). The paper presents a risk-based approach for optimal planning of Operation...

  15. Assessment of diagnostic and prognostic condition indices for efficient and robust maintenance decision-making of systems subject to stress corrosion cracking

    International Nuclear Information System (INIS)

    Huynh, K.T.; Grall, A.; Bérenguer, C.

    2017-01-01

    Seeking condition indices characterizing the health state of a system is a key problem in condition-based maintenance. For this purpose, diagnostic and prognostic models have been unceasingly developed and improved over the past few decades; nevertheless none of them explains thoroughly the impacts of such indices on the effectiveness of maintenance operations. As a complement to these efforts, this paper analyzes the effectiveness of some well-known diagnostic and prognostic indices for maintenance decision-making. The study is based on a system subject to competing risks due to multiple crack paths. A periodic inspection scheme is used to monitor the system health state. Each inspection returns the perfect diagnostic information: the number of cracks, corresponding crack sizes, and the system failure/working state. Based on this information, two kinds of prognostic condition indices are predicted: the average value and probability law of the system residual useful life. The associated condition-based maintenance strategies and cost models are then developed and compared with the ones whose maintenance decisions are based on diagnostic condition indices. The comparison results allow us to conclude on the performance and on the robustness of these strategies, hence giving some suggestions on the choice of reliable condition indices for maintenance decision-making. - Highlights: • Developing a new and generic degradation and failure model. • Synthesizing diagnostic and prognostic condition indices on the basis of the developed degradation and failure model. • Building diagnosis and prognosis-based maintenance strategies, and developing the associated cost models. • Assessing the performance and robustness of the considered strategies to find out reliable indices.

  16. A decision-making framework to integrate maintenance contract conditions with critical spares management

    International Nuclear Information System (INIS)

    Godoy, David R.; Pascual, Rodrigo; Knights, Peter

    2014-01-01

    Maintenance outsourcing is a strategic driver for asset intensive industries pursuing to enhance supply chain performance. Spare parts management plays a relevant role in this premise since its significant impact on equipment availability, and hence on business success. Designing critical spares policies might therefore seriously affect maintenance contracts profitability, yet service receivers and external providers traditionally attempt to benefit separately. To coordinate both chain parties, we investigated whether the spare components pool should be managed in-house or contracted out. This paper provides a decision-making framework to efficiently integrate contractual conditions with critical spares stockholding. Using an imperfect maintenance strategy over a finite horizon, the scheme maximizes chain returns whilst evaluating the impact of an additional part to stock. As result, an original joint value – preventive interval and stock level – sets the optimal agreement to profitably allocate the components pool within the service contract. Subsidization bonuses on preventive interventions and pooling costs are also estimated to induce the service provider to adjust its policy when needed. The proposed contractual conditions motivate stakeholders to continuously improve maintenance performance and supply practices, thus obtaining higher joint benefits

  17. Condition based spare parts supply

    NARCIS (Netherlands)

    Lin, X.; Basten, Robertus Johannes Ida; Kranenburg, A.A.; van Houtum, Geert-Jan

    2012-01-01

    We consider a spare parts stock point that serves an installed base of machines. Each machine contains the same critical component, whose degradation behavior is described by a Markov process. We consider condition based spare parts supply, and show that an optimal, condition based inventory policy

  18. Cernavoda NPP risk - Based test and maintenance planning - Methodology development

    International Nuclear Information System (INIS)

    Georgescu, G.; Popa, P.; Petrescu, A.; Naum, M.; Gutu, M.

    1997-01-01

    The Cernavoda Power Plant starts the commercial operation in November 1996. During operation of the nuclear power plant, several mandatory tests and maintenance are performed on stand-by safety system components to ensure their availability in case of accident. The basic purpose of such activities is the early detection of any failure and degradation, and timely correction of deteriorations. Because of the large number of such activities, emphasis on plant safety and allocation of resources becomes difficult. The probabilistic model and methodology can be effectively used to obtain the risk significance of these activities so that the resources are directed to the most important areas. The proposed Research Contract activity is strongly connected with other safety related areas under development. Since, the Cernavoda Probabilistic Safety Evaluation Level 1 PSA Study (CPSE) was performed and now the study is revised taking into account the as-built information, it is recommended to implement into the model the necessary modeling features to support further PSA application, especially related to Test and Maintenance optimization. Methods need to be developed in order to apply the PSA model including risk information together with other needed information for Test and Maintenance optimization. Also, in parallel with the CPSE study updating, the software interface for the PSA model is under development (Risk Monitor Software class), methods and models needing to be developed for the purpose of using it for qualified monitoring of Test and Maintenance Strategy efficiency. Similar, the Data Collection System need to be appropriate for the purpose of an ongoing implementation of a risk - based Test and Maintenance Strategy. (author). 4 refs, 1 fig

  19. Reliability-centered maintenance for ground-based large optical telescopes and radio antenna arrays

    Science.gov (United States)

    Marchiori, G.; Formentin, F.; Rampini, F.

    2014-07-01

    In the last years, EIE GROUP has been more and more involved in large optical telescopes and radio antennas array projects. In this frame, the paper describes a fundamental aspect of the Logistic Support Analysis (LSA) process, that is the application of the Reliability-Centered Maintenance (RCM) methodology for the generation of maintenance plans for ground-based large optical telescopes and radio antennas arrays. This helps maintenance engineers to make sure that the telescopes continue to work properly, doing what their users require them to do in their present operating conditions. The main objective of the RCM process is to establish the complete maintenance regime, with the safe minimum required maintenance, carried out without any risk to personnel, telescope and subsystems. At the same time, a correct application of the RCM allows to increase the cost effectiveness, telescope uptime and items availability, and to provide greater understanding of the level of risk that the organization is managing. At the same time, engineers shall make a great effort since the initial phase of the project to obtain a telescope requiring easy maintenance activities and simple replacement of the major assemblies, taking special care on the accesses design and items location, implementation and design of special lifting equipment and handling devices for the heavy items. This maintenance engineering framework is based on seven points, which lead to the main steps of the RCM program. The initial steps of the RCM process consist of: system selection and data collection (MTBF, MTTR, etc.), definition of system boundaries and operating context, telescope description with the use of functional block diagrams, and the running of a FMECA to address the dominant causes of equipment failure and to lay down the Critical Items List. In the second part of the process the RCM logic is applied, which helps to determine the appropriate maintenance tasks for each identified failure mode. Once

  20. Laser-Based Maintenance and Repair Technologies for Reactor Components

    International Nuclear Information System (INIS)

    Masaki Yoda; Naruhiko Mukai; Makoto Ochiai; Masataka Tamura; Satoshi Okada; Katsuhiko Sato; Motohiko Kimura; Yuji Sano; Noboru Saito; Seishi Shima; Tetsuo Yamamoto

    2004-01-01

    Toshiba has developed various laser-based maintenance and repair technologies and applied them to existing nuclear power plants. Laser-based technology is considered to be the best tool for remote processing in nuclear power plants, and particularly so for the maintenance and repair of reactor core components. Accessibility could be drastically improved by a simple handling system owing to the absence of reactive force against laser irradiation and the flexible optical fiber. For the preventive maintenance, laser peening (LP) technology was developed and applied to reactor components in operating BWR plants. LP is a novel process to improve residual stress from tensile to compressive on material surface layer by irradiating focused high-power laser pulses in water. We have developed a fiber-delivered LP system as a preventive maintenance measure against stress corrosion cracking (SCC). Laser ultrasonic testing (LUT) has a great potential to be applied to the remote inspection of reactor components. Laser-induced surface acoustic wave (SAW) inspection system was developed using a compact probe with a multi-mode optical fiber and an interferometer. The developed system successfully detected a micro slit of 0.5 mm depth on weld metal and heat-affected zone (HAZ). An artificial SCC was also detected by the system. We are developing a new LP system combined with LUT to treat the inner surface of bottom-mounted instruments (BMI) of PWR plants. Underwater laser seal welding (LSW) technology was also developed to apply surface crack. LSW is expected to isolate the crack tip from corrosive water environment and to stop the propagation of the crack. Rapid heating and cooling of the process minimize the heat effect, which extends the applicability to neutron-irradiated material. This paper describes recent advances in the development and application of such laser-based technologies. (authors)

  1. Optimizing Maintenance of Constraint-Based Database Caches

    Science.gov (United States)

    Klein, Joachim; Braun, Susanne

    Caching data reduces user-perceived latency and often enhances availability in case of server crashes or network failures. DB caching aims at local processing of declarative queries in a DBMS-managed cache close to the application. Query evaluation must produce the same results as if done at the remote database backend, which implies that all data records needed to process such a query must be present and controlled by the cache, i. e., to achieve “predicate-specific” loading and unloading of such record sets. Hence, cache maintenance must be based on cache constraints such that “predicate completeness” of the caching units currently present can be guaranteed at any point in time. We explore how cache groups can be maintained to provide the data currently needed. Moreover, we design and optimize loading and unloading algorithms for sets of records keeping the caching units complete, before we empirically identify the costs involved in cache maintenance.

  2. Improvement of testing and maintenance based on fault tree analysis

    International Nuclear Information System (INIS)

    Cepin, M.

    2000-01-01

    Testing and maintenance of safety equipment is an important issue, which significantly contributes to safe and efficient operation of a nuclear power plant. In this paper a method, which extends the classical fault tree with time, is presented. Its mathematical model is represented by a set of equations, which include time requirements defined in the house event matrix. House events matrix is a representation of house events switched on and off through the discrete points of time. It includes house events, which timely switch on and off parts of the fault tree in accordance with the status of the plant configuration. Time dependent top event probability is calculated by the fault tree evaluations. Arrangement of components outages is determined on base of minimization of mean system unavailability. The results show that application of the method may improve the time placement of testing and maintenance activities of safety equipment. (author)

  3. Lead particle size and its association with firing conditions and range maintenance: implications for treatment.

    Science.gov (United States)

    Dermatas, Dimitris; Chrysochoou, Maria

    2007-08-01

    Six firing range soils were analyzed, representing different environments, firing conditions, and maintenance practices. The particle size distribution and lead (Pb) concentration in each soil fraction were determined for samples obtained from the backstop berms. The main factors that were found to influence Pb fragment size were the type of soil used to construct the berms and the type of weapon fired. The firing of high velocity weapons, i.e., rifles, onto highly angular soils induced significant fragmentation of the bullets and/or pulverization of the soil itself. This resulted in the accumulation of Pb in the finer soil fractions and the spread of Pb contamination beyond the vicinity of the backstop berm. Conversely, the use of clay as backstop and the use of low velocity pistols proved to be favorable for soil clean-up and range maintenance, since Pb was mainly present as large metallic fragments that can be recovered by a simple screening process. Other factors that played important roles in Pb particle size distribution were soil chemistry, firing distance, and maintenance practices, such as the use of water spray for dust suppression and deflectors prior to impact. Overall, coarse Pb particles provide much easier and more cost-effective maintenance, soil clean-up, and remediation via physical separation. Fine Pb particles release Pb more easily, pose an airborne Pb hazard, and require the application of stabilization/solidification treatment methods. Thus, to ensure sustainable firing range operations by means of cost-effective design, maintenance, and clean-up, especially when high velocity weapons are used, the above mentioned factors should be carefully considered.

  4. Preventive maintenance plan of the air-conditioning duct using the ACM-sensor

    International Nuclear Information System (INIS)

    Fukuba, Kazushi; Ito, Takanobu; Kojima, Akiko; Tanji, Kazuhiro; Sato, Yuki

    2013-01-01

    Air-conditioning duct is difficult to predict the date to occur of corrosion such as affect the function. Therefore, the current conservation method is mostly corrective maintenance. Therefore, we used the test pieces of six types and ACM-sensor in order to solve the corrosion speed from corrosion environment and relationship of corrosion quantity of test pieces. In addition, was used the duct molded articles various in order to check the corrosion degree of when processed the duct. As a result, we were selected crust body constituting a duct and optimal combination of the flange by solve the corrosion speed of the test pieces various. Thus, it performs preventive disposal before to occur of corrosion such as affect the function by predicting the duct life from corrosion speed, and lead to stability and safe operating by appropriate maintenance of equipment. (author)

  5. Game-Theoretic Models for Usage-based Maintenance Contract

    Science.gov (United States)

    Husniah, H.; Wangsaputra, R.; Cakravastia, A.; Iskandar, B. P.

    2018-03-01

    A usage-based maintenance contracts with coordination and non coordination between two parties is studied in this paper. The contract is applied to a dump truck operated in a mining industry. The situation under study is that an agent offers service contract to the owner of the truck after warranty ends. This contract has only a time limit but no usage limit. If the total usage per period exceeds the maximum usage allowed in the contract, then the owner will be charged an additional cost. In general, the agent (Original Equipment Manufacturer/OEM) provides a full coverage of maintenance, which includes PM and CM under the lease contract. The decision problem for the owner is to select the best option offered that fits to its requirement, and the decision problem for the agent is to find the optimal maintenance efforts for a given price of the service option offered. We first find the optimal decisions using coordination scheme and then with non coordination scheme for both parties.

  6. A multi-agent based intelligent configuration method for aircraft fleet maintenance personnel

    OpenAIRE

    Feng, Qiang; Li, Songjie; Sun, Bo

    2014-01-01

    A multi-agent based fleet maintenance personnel configuration method is proposed to solve the mission oriented aircraft fleet maintenance personnel configuration problem. The maintenance process of an aircraft fleet is analyzed first. In the process each aircraft contains multiple parts, and different parts are repaired by personnel with different majors and levels. The factors and their relationship involved in the process of maintenance are analyzed and discussed. Then the whole maintenance...

  7. Geometric Process-Based Maintenance and Optimization Strategy for the Energy Storage Batteries

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-01-01

    Full Text Available Renewable energy is critical for improving energy structure and reducing environment pollution. But its strong fluctuation and randomness have a serious effect on the stability of the microgrid without the coordination of the energy storage batteries. The main factors that influence the development of the energy storage system are the lack of valid operation and maintenance management as well as the cost control. By analyzing the typical characteristics of the energy storage batteries in their life cycle, the geometric process-based model including the deteriorating system and the improving system is firstly built for describing the operation process, the preventive maintenance process, and the corrective maintenance process. In addition, this paper proposes an optimized management strategy, which aims to minimize the long-run average cost of the energy storage batteries by defining the time interval of the detection and preventive maintenance process as well as the optimal corrective maintenance times, subjected to the state of health and the reliability conditions. The simulation is taken under the built model by applying the proposed energy storage batteries’ optimized management strategy, which verifies the effectiveness and applicability of the management strategy, denoting its obvious practicality on the current application.

  8. A maintenance optimization model for mission-oriented systems based on Wiener degradation

    International Nuclear Information System (INIS)

    Guo, Chiming; Wang, Wenbin; Guo, Bo; Si, Xiaosheng

    2013-01-01

    Over the past few decades, condition-based maintenance (CBM) has attracted many researchers because of its effectiveness and practical significance. This paper deals with mission-oriented systems subject to gradual degradation modeled by a Wiener stochastic process within the context of CBM. For a mission-oriented system, the mission usually has constraints on availability/reliability, the opportunity for maintenance actions, and the monitoring type (continuous or discrete). Furthermore, in practice, a mission-oriented system may undertake some preventive maintenance (PM) and after such PM, the system may return to an intermediate state between an as-good-as new state and an as-bad-as old state, i.e., the PM is not perfect and only partially restores the system. However, very few CBM models integrated these mission constraints together with an imperfect nature of the PM into the course of optimizing the PM policy. This paper develops a model to optimize the PM policy in terms of the maintenance related cost jointly considering the mission constraints and the imperfect PM nature. A numerical example is presented to demonstrate the proposed model. The comparison with the simulated results and the sensitivity analysis show the usefulness of the optimization model for mission-oriented system maintenance presented in this paper.

  9. Hypertext-based integration for nuclear plant maintenance and operations

    International Nuclear Information System (INIS)

    Tsoukalas, L.H.; Upadhyaya, B.R.

    1991-01-01

    A methodology is presented that uses fuzzy graphs in the emerging paradigm of hypertext for the purpose of integrating data, information and multifaceted knowledge resources abounding in power plant operations and maintenance. A hypertext system is viewed as a set of nodes and links where with each link we associate membership functions embodying context-dependent criteria for navigating large information spaces. A general framework for navigation is outlined and graph-theory navigational tools are developed. A numerical example and a HyperCard-based prototype for monitoring special material in the MHTGR-NPR are included. 10 refs., 12 figs

  10. Optimisation of test and maintenance based on probabilistic methods

    International Nuclear Information System (INIS)

    Cepin, M.

    2001-01-01

    This paper presents a method, which based on models and results of probabilistic safety assessment, minimises the nuclear power plant risk by optimisation of arrangement of safety equipment outages. The test and maintenance activities of the safety equipment are timely arranged, so the classical static fault tree models are extended with the time requirements to be capable to model real plant states. A house event matrix is used, which enables modelling of the equipment arrangements through the discrete points of time. The result of the method is determination of such configuration of equipment outages, which result in the minimal risk. Minimal risk is represented by system unavailability. (authors)

  11. Failure and Maintenance Analysis Using Web-Based Reliability Database System

    International Nuclear Information System (INIS)

    Hwang, Seok Won; Kim, Myoung Su; Seong, Ki Yeoul; Na, Jang Hwan; Jerng, Dong Wook

    2007-01-01

    Korea Hydro and Nuclear Power Company has lunched the development of a database system for PSA and Maintenance Rule implementation. It focuses on the easy processing of raw data into a credible and useful database for the risk-informed environment of nuclear power plant operation and maintenance. Even though KHNP had recently completed the PSA for all domestic NPPs as a requirement of the severe accident mitigation strategy, the component failure data were only gathered as a means of quantification purposes for the relevant project. So, the data were not efficient enough for the Living PSA or other generic purposes. Another reason to build a real time database is for the newly adopted Maintenance Rule, which requests the utility to continuously monitor the plant risk based on its operation and maintenance performance. Furthermore, as one of the pre-condition for the Risk Informed Regulation and Application, the nuclear regulatory agency of Korea requests the development and management of domestic database system. KHNP is stacking up data of operation and maintenance on the Enterprise Resource Planning (ERP) system since its first opening on July, 2003. But, so far a systematic review has not been performed to apply the component failure and maintenance history for PSA and other reliability analysis. The data stored in PUMAS before the ERP system is introduced also need to be converted and managed into the new database structure and methodology. This reliability database system is a web-based interface on a UNIX server with Oracle relational database. It is designed to be applicable for all domestic NPPs with a common database structure and the web interfaces, therefore additional program development would not be necessary for data acquisition and processing in the near future. Categorization standards for systems and components have been implemented to analyze all domestic NPPs. For example, SysCode (for a system code) and CpCode (for a component code) were newly

  12. Risk based maintenance to increase safety and decrease costs

    International Nuclear Information System (INIS)

    Phillips, J.H.

    2000-01-01

    Risk-Based techniques have been developed for commercial nuclear power plants for the last eight years by a team working through the ASME Center for Research and Technology Development (CRTD). System boundaries and success criteria is defined using the Probabilistic Risk Analysis or Probabilistic Safety Analysis developed to meet the Individual Plant Evaluation. Final ranking of components is by a plant expert panel similar to the one developed for the Maintenance Rule. Components are identified as being high risk-significant or low risk-significant. Maintenance and resources are focused on those components that have the highest risk-significance. The techniques have been developed and applied at a number of plants. Results from the first risk-based inspection pilot plant indicates safety due to pipe failure can be doubled while the inspection reduced to about 80% when compared with current inspection programs. Pilot studies on risk-based testing indicate that about 60% of pumps and 25 to 30% of valves in plants are high safety-significant The reduction in inspection and testing reduces the person-rem exposure and resulting in further increases in safety. These techniques have been documented in publications by the ASME CRTD which are referenced. (author)

  13. Investigation of an innovative maintenance contracting strategy : the performance-based maintenance contract (PBMC).

    Science.gov (United States)

    2015-06-01

    One of the major responsibilities of state Departments of Transportation (DOTs) is to maintain their road assets so : that road users can travel cost effectively, safely, and in a timely manner. Maintenance projects can be performed : either by using...

  14. In vitro maintenance, under slow-growth conditions, of oil palm germplasm obtained by embryo rescue

    Directory of Open Access Journals (Sweden)

    Julcéia Camillo

    2015-05-01

    Full Text Available The objective of this work was to evaluate the in vitro maintenance of oil palm (Elaeis guineensis and E. oleifera accessions under slow-growth conditions. Plants produced by embryo rescue were subject to 1/2MS culture medium supplemented with the carbohydrates sucrose, mannitol, and sorbitol at 1, 2, and 3% under 20 and 25±2ºC. After 12 months, the temperature of 20°C reduced plant growth. Sucrose is the most appropriate carbohydrate for maintaining the quality of the plants, whereas mannitol and sorbitol result in a reduced plant survival.

  15. Framework for Risk-based Planning of Operation and Maintenance for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2009-01-01

    , and to sequential optimal decision making on planning of OM taking into account new information. Deterioration mechanisms such as fatigue, corrosion, wear and erosion are associated with significant uncertainty. Observations of the degree of damage can increase the reliability of predictions, especially......For offshore wind turbines, costs to operation and maintenance (OM) are substantial. This paper describes a risk-based life cycle approach for optimal planning of OM. The approach is based on pre-posterior Bayesian decision theory, and can be used both to overall, initial planning of OM...... in connection with condition-based maintenance. The approach can be used for gearboxes, generators, fatigue cracks, corrosion, etc. This paper also describes how probabilistic indicators can be used to quantify indirect information about the damage state for critical components, e.g. gearboxes....

  16. Utility based maintenance analysis using a Random Sign censoring model

    International Nuclear Information System (INIS)

    Andres Christen, J.; Ruggeri, Fabrizio; Villa, Enrique

    2011-01-01

    Industrial systems subject to failures are usually inspected when there are evident signs of an imminent failure. Maintenance is therefore performed at a random time, somehow dependent on the failure mechanism. A competing risk model, namely a Random Sign model, is considered to relate failure and maintenance times. We propose a novel Bayesian analysis of the model and apply it to actual data from a water pump in an oil refinery. The design of an optimal maintenance policy is then discussed under a formal decision theoretic approach, analyzing the goodness of the current maintenance policy and making decisions about the optimal maintenance time.

  17. A comprehensive approach to RCM-based preventive maintenance program development

    International Nuclear Information System (INIS)

    Hall, B.E.; Davis, T.; Pennington, A.J.

    1988-01-01

    In late 1986, Public Service Electric and Gas Company (PSE ampersand G) concluded that to support its vision and strategic planning it would be necessary to develop a consistent approach to maintenance for all nuclear units at the artificial island. General Physics Corporation was selected to lead a consultant team to support full-scale development of a preventive maintenance (PM) program for Salem and Hope Creek generating stations based on a reliability-centered maintenance (RCM) approach. RCM was selected because it represents a systematic approach to developing a PM program that provides a logical, consistent, and traceable methodology and produces a well-documented engineering basis for the program. Early in 1987, primary objectives for the PM program were defined. The Phase I tasks addressed key programmatic areas such as maintenance philosophy, procedures, condition monitoring, performance trending, equipment failure data base, ogranization, PM program effectiveness evaluation, RCM process, reliability/availability modeling, information management, training, spare parts, software/hardware, and commitments. Phase I of the PM program development project was completed in January 1988. Highlights of the Phase I work and the PM program manual are described

  18. Review on the Pavement-repairing Measures as a Condition for the Choice of Road-Maintenance Strategy

    Directory of Open Access Journals (Sweden)

    Nedevska Ivana

    2017-01-01

    Full Text Available The road-maintenance strategies vary from one country to another, and even between the road management authorities within a one single country. It is not surprising, as there is not best maintenance method, nor a universal set of strategies that can be applied equally everywhere. Generally, there are strategies acceptable in certain conditions, but the factors influencing the selection process are diverse and very complex. This paper will present a review of the various measures that can be applied on the roads, which is certainly the basic condition of selection of an appropriate maintenance strategy.

  19. Airbus A320 NEO Base Maintenance Concept SAS Operations

    OpenAIRE

    Dafgård, Oscar

    2017-01-01

    Detta arbete har utförts tillsammans med SAS, för att undersöka om ett base maintenance koncept med ett intervall på 36 månader skulle vara mer kostnadseffektivt än 24 månader för deras nya Airbus A320 NEO flotta. SAS, precis som alla andra flygbolag utnyttjar sina flygplan på sina egna och specifika vis. Eftersom inga flygbolag opererar på samma sätt kan inte heller underhållet skötas på samma sätt för en specifik flygplanstyp. Underhållsprogrammet behövde därför ses över för att optimeras g...

  20. Case-Base Maintenance for CCBR-Based Process Evolution

    NARCIS (Netherlands)

    Weber, B.; Reichert, M.U.; Wild, W.; Roth-Berghofer, T.; Göker, M.H.; Güvenir, H.A.

    2006-01-01

    The success of a company more and more depends on its ability to flexibly and quickly react to changes. Combining process management techniques and conversational case-based reasoning (CCBR) allows for flexibly aligning the business processes to new requirements by providing integrated process life

  1. Decommissioning and Dismantling of the Floating Maintenance Base 'Lepse' - 13316

    International Nuclear Information System (INIS)

    Field, D.; Mizen, K.

    2013-01-01

    The Lepse was built in Russia in 1934 and commissioned as a dry cargo ship. In 1961 she was re-equipped for use as a nuclear service ship (NSS), specifically a floating maintenance base (FMB), to support the operation of the civilian nuclear fleet (ice-breakers) of the USSR. In 1988 Lepse was taken out of service and in 1990 she was re-classified as a 'berth connected ship', located at a berth near the port of Murmansk under the ownership of Federal State Unitary Enterprise (FSUE) Atomflot. Lepse has special storage facilities for spent nuclear fuel assemblies (SFA) that have been used to store several hundred SFAs for nearly 40 years. High and intermediate-level liquid radioactive waste (LRW) is also present in the spent nuclear fuel assembly storage channels, in special tanks and also in the SFA cooling circuit. Many of the SFAs stored in Lepse are classified as damaged and cannot be removed using standard procedures. The removal of the SFA and LRW from the Lepse storage facilities is a hazardous task and requires specially designed tools, equipment and an infrastructure in which these can be deployed safely. Lepse is a significant environmental hazard in the North West of Russia. Storing spent nuclear fuel and high-level liquid radioactive waste on board Lepse in the current conditions is not acceptable with respect to Russian Federation health, safety and environmental standards and with international best practice. The approved concept design for the removal of the SFA and LRW and dismantling of Lepse requires that the ship be transported to Nerpa shipyard where specialist infrastructure will be constructed and equipment installed. One of the main complexities of the Project lies within the number of interested stakeholders involved in the Project. The Lepse project has been high focus on the international stage for many years with previous international efforts failing to make significant progress towards the objective of decommissioning Lepse. The Northern

  2. A cost effective degradation-based maintenance strategy under imperfect repair

    International Nuclear Information System (INIS)

    Wu, Fan; Niknam, Seyed A.; Kobza, John E.

    2015-01-01

    An optimization model is developed to minimize the total cost of imperfect degradation-based maintenance by determining an optimal interval of condition monitoring and the degradation level after imperfect preventive repairs. The decision model is based on a novel cost model that considers functional relationship between the expected degradation reduction and the cost of preventive repairs. The decision model is applied to simulated vibration signals with a variety of specifications of cost values and degradation model parameters. This study has initiated a new area for the research of cost effective maintenance strategies. The results clearly indicate the significance of the proposed model and the decision variables under the objective of minimal cost. For instance, the results indicate direct relationship between the optimal length of monitoring interval and the monitoring cost. However, longer monitoring interval increases the risk of failure, and therefore, more degradation reduction is needed. By increasing the slope of cumulative degradation, the cost effective strategy advocates taking more frequent monitoring. The optimal degradation level after each preventive repair is not so sensitive to the change in the degradation slope due to the uncertainty associated with degradation patterns. - Highlights: • Discuss the relationship of degradation reduction and maintenance cost. • Determine the optimal interval of condition monitoring with minimal cost. • Identify the optimal degradation level after imperfect preventive repairs. • Discuss the effects of change in the slope of cumulative degradation.

  3. The present condition of forest roads as a result of their past maintenance

    OpenAIRE

    Hribernik, Boštjan; Potočnik, Igor

    2006-01-01

    Forest roads are built for forest management purposes, to which planning of their use and maintenance is adapted. The increasing importance of non-forestry use of forest roads leads to higher maintenance standard, which by formed maintenance system causes permanent shortage of funds. Higher maintenance costs occur due to the past forest roads construction characteristics, which gave priority to quick opening of villages and farms, on the account of building quality. Other funds expenditure re...

  4. An evaluation of the Browns Ferry Nuclear Plant preventive maintenance program based on reliability centered maintenance analysis

    International Nuclear Information System (INIS)

    McCullough, C.L.; McCullough, C.A.

    1989-01-01

    Reliability centered maintenance (RCM) techniques were used to support a preventative maintenance (PM) upgrade program (PMUP) performed at TVA Browns Ferry Nuclear Plant (BFNP). The purpose of the RCM analysis was to identify critical equipment based on risk and economic importance and to evaluate the PM activities applicable to that equipment. The analysis may be conveniently divided into three steps, which will be outlined in the Approach section of this paper. The net benefit of the RCM approach was a prioritization of the focus of the PM upgrade program so that plant components receive attention proportional to their importance, and assurance that PM activities properly address the most likely component failure causes

  5. Continuous improvement of operation and maintenance conditions of french PWR nuclear islands

    International Nuclear Information System (INIS)

    Bitsch, D.

    1985-05-01

    Improvement of the nuclear island design, to facilitate maintenance and working conditions during plant shutdown, has been a subject of particular attention within the French PWR program. Standardization and industrial concentration created an unusually favourable context for approaching this objective. Progress efforts supported by the feedback of actual operating experience were pursued in the areas of plant layout-equipment installation, and on the design and technology of the component themselves. The progress efforts on the design and technology of the components were pursued along several paths including: - the resistance increase of specific parts submitted to various forms of in-service damage, - the reduction of the extent and duration of work during plant outages and - the reduction of the Occupational Radiation Exposure (ORE), one of the most important axes of development, through the appropriate selection of less releasing materials, the implementation of more efficient decontamination systems and by the use of robots

  6. Maintenance strategy for tilting table of rolling mill based on reliability considerations

    International Nuclear Information System (INIS)

    Deshpande, V.S.; Modak, J.P.

    2003-01-01

    tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices

  7. PSO Based Optimization of Testing and Maintenance Cost in NPPs

    Directory of Open Access Journals (Sweden)

    Qiang Chou

    2014-01-01

    Full Text Available Testing and maintenance activities of safety equipment have drawn much attention in Nuclear Power Plant (NPP to risk and cost control. The testing and maintenance activities are often implemented in compliance with the technical specification and maintenance requirements. Technical specification and maintenance-related parameters, that is, allowed outage time (AOT, maintenance period and duration, and so forth, in NPP are associated with controlling risk level and operating cost which need to be minimized. The above problems can be formulated by a constrained multiobjective optimization model, which is widely used in many other engineering problems. Particle swarm optimizations (PSOs have proved their capability to solve these kinds of problems. In this paper, we adopt PSO as an optimizer to optimize the multiobjective optimization problem by iteratively trying to improve a candidate solution with regard to a given measure of quality. Numerical results have demonstrated the efficiency of our proposed algorithm.

  8. Online Condition Monitoring of Bearings to Support Total Productive Maintenance in the Packaging Materials Industry.

    Science.gov (United States)

    Gligorijevic, Jovan; Gajic, Dragoljub; Brkovic, Aleksandar; Savic-Gajic, Ivana; Georgieva, Olga; Di Gennaro, Stefano

    2016-03-01

    The packaging materials industry has already recognized the importance of Total Productive Maintenance as a system of proactive techniques for improving equipment reliability. Bearing faults, which often occur gradually, represent one of the foremost causes of failures in the industry. Therefore, detection of their faults in an early stage is quite important to assure reliable and efficient operation. We present a new automated technique for early fault detection and diagnosis in rolling-element bearings based on vibration signal analysis. Following the wavelet decomposition of vibration signals into a few sub-bands of interest, the standard deviation of obtained wavelet coefficients is extracted as a representative feature. Then, the feature space dimension is optimally reduced to two using scatter matrices. In the reduced two-dimensional feature space the fault detection and diagnosis is carried out by quadratic classifiers. Accuracy of the technique has been tested on four classes of the recorded vibrations signals, i.e., normal, with the fault of inner race, outer race, and ball operation. The overall accuracy of 98.9% has been achieved. The new technique can be used to support maintenance decision-making processes and, thus, to increase reliability and efficiency in the industry by preventing unexpected faulty operation of bearings.

  9. Online Condition Monitoring of Bearings to Support Total Productive Maintenance in the Packaging Materials Industry

    Directory of Open Access Journals (Sweden)

    Jovan Gligorijevic

    2016-03-01

    Full Text Available The packaging materials industry has already recognized the importance of Total Productive Maintenance as a system of proactive techniques for improving equipment reliability. Bearing faults, which often occur gradually, represent one of the foremost causes of failures in the industry. Therefore, detection of their faults in an early stage is quite important to assure reliable and efficient operation. We present a new automated technique for early fault detection and diagnosis in rolling-element bearings based on vibration signal analysis. Following the wavelet decomposition of vibration signals into a few sub-bands of interest, the standard deviation of obtained wavelet coefficients is extracted as a representative feature. Then, the feature space dimension is optimally reduced to two using scatter matrices. In the reduced two-dimensional feature space the fault detection and diagnosis is carried out by quadratic classifiers. Accuracy of the technique has been tested on four classes of the recorded vibrations signals, i.e., normal, with the fault of inner race, outer race, and ball operation. The overall accuracy of 98.9% has been achieved. The new technique can be used to support maintenance decision-making processes and, thus, to increase reliability and efficiency in the industry by preventing unexpected faulty operation of bearings.

  10. Risk based test interval and maintenance optimisation - Application and uses

    International Nuclear Information System (INIS)

    Sparre, E.

    1999-10-01

    The project is part of an IAEA co-ordinated Research Project (CRP) on 'Development of Methodologies for Optimisation of Surveillance Testing and Maintenance of Safety Related Equipment at NPPs'. The purpose of the project is to investigate the sensitivity of the results obtained when performing risk based optimisation of the technical specifications. Previous projects have shown that complete LPSA models can be created and that these models allow optimisation of technical specifications. However, these optimisations did not include any in depth check of the result sensitivity with regards to methods, model completeness etc. Four different test intervals have been investigated in this study. Aside from an original, nominal, optimisation a set of sensitivity analyses has been performed and the results from these analyses have been compared to the original optimisation. The analyses indicate that the result of an optimisation is rather stable. However, it is not possible to draw any certain conclusions without performing a number of sensitivity analyses. Significant differences in the optimisation result were discovered when analysing an alternative configuration. Also deterministic uncertainties seem to affect the result of an optimisation largely. The sensitivity of failure data uncertainties is important to investigate in detail since the methodology is based on the assumption that the unavailability of a component is dependent on the length of the test interval

  11. PLC based control system and maintenance activities at NCAR, Bilaspur

    International Nuclear Information System (INIS)

    Dewangan, Jaidev; Trivedi, T.; Patel, Shiv P.; Malik, C.; Kumar, Rakesh; Gupta, Santosh Kumar; Bajpai, P.K.

    2015-01-01

    A 3.0 MV high current low energy Pelletron Accelerator facility (Model 9SDH-4, NEC, USA) with TORUIS (ion source for H + and He 2+ beam current H + ion ∼ 50μA @ 6 MeV, He 2+ at ∼ 10μA) and SNICS-II ion source for heavy ions has been commissioned as 'National Centre for Accelerator Based Research' in the Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya. In this paper, we detail out the control system developed and implemented at NCAR. The basic idea of controlling the machine is by providing the output signal through PLC to ACPC of accelerator using user interface points provided by the manufacturer. The PLC based system generates output signal once it receives the feedback signals from search and secure switches, door lock switches and scram switches interlocked with PLC. The output is controlled by ladder logic and is activated only when all the radiation monitors are in healthy state and outside radiations monitor having low radiation level. The details of control system and maintenance activities will be discussed in the paper

  12. 45 CFR 310.20 - What are the conditions for funding the installation, operation, maintenance and enhancement of...

    Science.gov (United States)

    2010-10-01

    ... Tribal IV-D Systems and Office Automation § 310.20 What are the conditions for funding the installation... 45 Public Welfare 2 2010-10-01 2010-10-01 false What are the conditions for funding the installation, operation, maintenance and enhancement of Computerized Tribal IV-D Systems and Office Automation...

  13. A multi-agent based intelligent configuration method for aircraft fleet maintenance personnel

    Directory of Open Access Journals (Sweden)

    Feng Qiang

    2014-04-01

    Full Text Available A multi-agent based fleet maintenance personnel configuration method is proposed to solve the mission oriented aircraft fleet maintenance personnel configuration problem. The maintenance process of an aircraft fleet is analyzed first. In the process each aircraft contains multiple parts, and different parts are repaired by personnel with different majors and levels. The factors and their relationship involved in the process of maintenance are analyzed and discussed. Then the whole maintenance process is described as a 3-layer multi-agent system (MAS model. A communication and reasoning strategy among the agents is put forward. A fleet maintenance personnel configuration algorithm is proposed based on contract net protocol (CNP. Finally, a fleet of 10 aircraft is studied for verification purposes. A mission type with 3 waves of continuous dispatch is imaged. Compared with the traditional methods that can just provide configuration results, the proposed method can provide optimal maintenance strategies as well.

  14. A Data Warehouse to Support Condition Based Maintenance (CBM)

    Science.gov (United States)

    2005-05-01

    Application ( VBA ) code sequence to import the original MAST-generated CSV and then create a single output table in DBASE IV format. The DBASE IV format...database architecture (Oracle, Sybase, MS- SQL , etc). This design includes table definitions, comments, specification of table attributes, primary and foreign...built queries and applications. Needs the application developers to construct data views. No SQL programming experience. b. Power Database User - knows

  15. Mathematical Frameworks for Diagnostics, Prognostics and Condition Based Maintenance Problems

    Science.gov (United States)

    2008-08-15

    frequency than its less constrained counterpart. This phenomenon is similar to the effect seen when tightening a guitar string. A tighter string vibrates...English speaking countries are required to have a minimum score of 500 on the Test of English as a Foreign Language (TOEFL). Unconditional Admission...have passed the National Council of Examiners for Engineering and Surveying (NCEES) Fundamentals of Engineering Examination, and • Minimum GRE scores

  16. Costs of performance based maintenance for local roads: Case study Albania

    Science.gov (United States)

    Jokanović, Igor; Grujić, Bojana; Zeljić, Dragana; Grujić, Žarko; Svilar, Mila

    2017-12-01

    The provision and maintenance of road infrastructure is a major global business, consequently it is essential that road maintenance services are provided in the most cost effective manner. Without regular maintenance, roads can rapidly fall into disrepair, preventing realization of the longer term impacts of road improvements on development, such as increased agricultural production and growth in school enrollment, which is of particular importance for a network of local (access) roads. Inadequate local roads maintenance in Albania is proposed to be solved by implementing performance based maintenance approach for which the costing exercise is presented within the paper.

  17. The development of web based power plant maintenance management system

    International Nuclear Information System (INIS)

    Kim, Bum Shin; Kim, Eui Hyun; Jang, Dong Sik; Cho, Jae Min; Chae, Gil Seok; Jung, Gyu Chol

    2004-01-01

    Most power plants have operated many independent computerize systems for maintenance. Independence of systems have caused complexity of business process and inconvenience of computer system management. Because the equipment and material master data is not standardize and structurize, it is difficult to manage equipment maintenance history and material delivery. Especially equipment classification criterion is important for standardization of every maintenance information. It is necessary to integrate function of independent systems for business process simplification and rapid work flow. This paper provides equipment classification criterion design and system integration method with the case of live system development

  18. The-Abstraction-Hierarchy-based Mobile PC Display Design for NPP Maintenance

    International Nuclear Information System (INIS)

    Kim, In; Kim, Bo Gyung; Seong, Poong Hyun; Ha, Jun Su

    2010-01-01

    Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. For improved and effective use of an MMA display design method based on abstraction hierarchy (AH) is proposed and its design considerations are discussed in this study. Six levels of abstraction hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using AH, maintenance information can be used effectively by users with either high or low levels of expertise. When information classification has been finished, the information for MMA design is selected and designed. With the considerations of MMA design analysis and guidelines, AH-based MMA is designed for the maintenance tasks. An experiment is conducted using the AH-based MMA in order to estimate the effectiveness of the proposed method for the maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that an AH-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the AH-based manual was estimated less than the conventional manual for subjects with low level of expertise. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become pervasive in NPP maintenance fields, AH-model applied MMAs can be used as an effective maintenance supporting tool

  19. Model-based fault diagnosis framework for effective predictive maintenance / B.B. Akindele

    OpenAIRE

    Akindele, Babatunde Babajide

    2010-01-01

    Predictive maintenance is a proactive maintenance strategy that is aimed at preventing the unexpected failure of equipment through condition monitoring of the health and performance of the equipment. Incessant equipment outage resulting in low availability of production facilities is a major issue in the Nigerian manufacturing environment. Improving equipment availability in Nigeria industry through institution of a full featured predictive maintenance has been suggested by many authors. T...

  20. Health risk air-conditioning system; Insufficient maintenance increases the risk of illness. Gesundheitsrisiko Klimaanlagen; Unzureichende Wartung erhoeht das Erkrankungsrisiko

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1994-01-01

    In Germany every fifth employee who works in air-conditioned rooms complains about headache, an increased proneness to colds and influenza infections as well as allergic reactions. These troubles are often caused by the insufficient maintenance of air-conditioning systems. At present only 15% of the estimated annual demand for maintenance of space hvac-systems is actually carried out. Problematic in case of air-conditioning systems are the so-called air washers used for air humidification which can become an ideal cultur medium for microorganisms. A second problematic area are the often very dirty filters. But health risks can be avoided with regular expert maintenance alone. As first step an analysis of the causes of faults is proposed. (BWI)

  1. Implementation strategies and tools for condition based monitoring at nuclear power plants

    International Nuclear Information System (INIS)

    2007-05-01

    There is now an acute need to optimize maintenance to improve both reliability and competitiveness of nuclear power plant operation. There is an increasing tendency to move from the preventive (time based) maintenance concept to one dependent on plant and component conditions. In this context, various on-line and off-line condition monitoring and diagnostics, nondestructive inspection techniques and surveillance are used. Component selection for condition based maintenance, parameter selection for monitoring condition, evaluation of condition monitoring results are issues influencing the effectiveness of condition based maintenance. All these selections of components and parameters to be monitored, monitoring and diagnostics techniques to be used, acceptance criteria and trending for condition evaluation, and the economic aspect of predictive maintenance and condition monitoring should be incorporated into an integrated, effective condition based maintenance programme, which is part of the plant's overall maintenance optimization programme. This publication collects and analyses proven condition based maintenance strategies and techniques (engineering and organizational) in Member States. It includes selected papers on maintenance optimization presented during its preparation. This report was prepared under IAEA project on integrated NPP life cycle management including decommissioning. The main objective of an integrated life cycle management programme is to enable NPP's to compete, without compromising safety, successfully in the changing energy markets throughout their service life and to facilitate life extension and eventual decommissioning through improved engineering, technological, economic and managerial actions. The technical working group on NPP life management and other advisory groups nominated by the Member States provide recommendations on high priority needs of Member States in this area

  2. Preventive Maintenance Interval Prediction: a Spare Parts Inventory Cost and Lost Earning Based Model

    Directory of Open Access Journals (Sweden)

    O. A. Adebimpe

    2015-06-01

    Full Text Available In this paper, some preventive maintenance parameters in manufacturing firms were identified and used to develop cost based functions in terms of machine preventive maintenance. The proposed cost based model considers system’s reliability, cost of keeping spare parts inventory and lost earnings in deriving optimal maintenance interval. A case of a manufacturing firm in Nigeria was observed and the data was used to evaluate the model.

  3. An Abstraction Hierarchy based mobile PC display design in NPP maintenance considering the level of expertise

    International Nuclear Information System (INIS)

    Yim, Ho Bin; Kim, In; Seong, Poong Hyun

    2011-01-01

    Research highlights: → Six levels of Abstraction Hierarchy based information for maintenance were proposed. → Errors and workload with AH based information display were reduced for LL subjects. → Design concerns discovered can be applied to practical use of mobile maintenance aids. - Abstract: Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. For improved and effective use of an MMA display design method based on the hierarchy is proposed and its design considerations are discussed in this study. Six levels of hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using the hierarchy, maintenance information can be used effectively by users with either high or low levels of expertise. When information classification has been finished, the information for MMA design is selected and designed. With the considerations of MMA design analysis and guidelines, a hierarchy-based MMA is designed for the maintenance tasks. An experiment is conducted using the hierarchy-based MMA in order to estimate the effectiveness of the proposed method for the maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that a hierarchy-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the hierarchy-based manual was estimated less than the conventional manual for subjects with low level of expertise. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become pervasive in NPP maintenance fields, the hierarchy model applied MMAs can be used as an effective maintenance supporting tool.

  4. Mathematical thinking of maintenance. Problem setting and solving bases

    International Nuclear Information System (INIS)

    2007-01-01

    Plant or mechanical facility for maintenance became more complicated than before and consisted of many subsystems made of various equipments or facilities with parts, which were a system having complicated and hierarchical structure. Maintenance was required to be properly implemented to assure reliability of a system for a long period so as for each equipment to play a specified role for a stable operation of plant. Mathematical thinking using probability theory was rational to optimize maintenance action with failure rate function of system or part of equipment. Reliability function, maintainability function and availability of plant and equipment were defined. Unreliability function was called failure time distribution function (F(t)) and failure rate function (λ(t)) was defined as the ratio of failure time density distribution function (dF(t)/dt) to reliability function (1-F(t)). λ(t) could be expressed as a simple equation with Weibull parameter. Availability at steady state was attributed to ratio of average operating time to sum of operating time and maintenance time, i.e. MTBF/(MTBF+MTTR) where MTBF was mean time between failures and MTTR was mean time to repair. Optimization of system risk and maintenance action was encouraged using computational science simulating material degradation. (T. Tanaka)

  5. The limiting conditional probability distribution in a stochastic model of T cell repertoire maintenance.

    Science.gov (United States)

    Stirk, Emily R; Lythe, Grant; van den Berg, Hugo A; Hurst, Gareth A D; Molina-París, Carmen

    2010-04-01

    The limiting conditional probability distribution (LCD) has been much studied in the field of mathematical biology, particularly in the context of epidemiology and the persistence of epidemics. However, it has not yet been applied to the immune system. One of the characteristic features of the T cell repertoire is its diversity. This diversity declines in old age, whence the concepts of extinction and persistence are also relevant to the immune system. In this paper we model T cell repertoire maintenance by means of a continuous-time birth and death process on the positive integers, where the origin is an absorbing state. We show that eventual extinction is guaranteed. The late-time behaviour of the process before extinction takes place is modelled by the LCD, which we prove always exists for the process studied here. In most cases, analytic expressions for the LCD cannot be computed but the probability distribution may be approximated by means of the stationary probability distributions of two related processes. We show how these approximations are related to the LCD of the original process and use them to study the LCD in two special cases. We also make use of the large N expansion to derive a further approximation to the LCD. The accuracy of the various approximations is then analysed. (c) 2009 Elsevier Inc. All rights reserved.

  6. Optimal, Risk-based Operation and Maintenance Planning for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2008-01-01

    For offshore wind turbines costs to operation and maintenance are substantial. This paper describes a risk-based life-cycle approach for optimal planning of operation and maintenance. The approach is based on pre-posterior Bayesian decision theory. Deterioration mechanisms such as fatigue...

  7. Design of Mobile Operation and Maintenance System Based on Power GIS and GPS

    Directory of Open Access Journals (Sweden)

    Jing TAO

    2017-01-01

    Full Text Available In order to solve the low efficiency of operation and maintenance and the problems of management coordination caused by the coexistence of off-line operation and maintenance and multi system coexistence in current power telecommunication operation and maintenance, this paper proposes a mobile operation and maintenance system based on power GIS and GPS location technology. The system is based on the C/S architecture, and the mobile operation and maintenance terminal is connected with the operation and maintenance management terminal through wireless and wired network. In addition to meeting basic business requirements, the system integrates power GIS functions to visually demonstrate communication resources, personnel, and failures. The staff can use the wireless mobile terminal which integrated GPS module for to operate and maintain, and can locate accurately in real time.

  8. Risk-Based Predictive Maintenance for Safety-Critical Systems by Using Probabilistic Inference

    Directory of Open Access Journals (Sweden)

    Tianhua Xu

    2013-01-01

    Full Text Available Risk-based maintenance (RBM aims to improve maintenance planning and decision making by reducing the probability and consequences of failure of equipment. A new predictive maintenance strategy that integrates dynamic evolution model and risk assessment is proposed which can be used to calculate the optimal maintenance time with minimal cost and safety constraints. The dynamic evolution model provides qualified risks by using probabilistic inference with bucket elimination and gives the prospective degradation trend of a complex system. Based on the degradation trend, an optimal maintenance time can be determined by minimizing the expected maintenance cost per time unit. The effectiveness of the proposed method is validated and demonstrated by a collision accident of high-speed trains with obstacles in the presence of safety and cost constrains.

  9. Regulatory requirements related to risk-based inspection and maintenance

    International Nuclear Information System (INIS)

    Schroeder, H.C.; Kauer, R.

    2003-01-01

    By asking the question why new inspection and maintenance strategies have to be developed one can often be made aware that there is always a continue demand for cost reduction and optimisation. In this framework, general trends involving staff reduction, outsourcing, benchmarking etc. can often be observed nearly everywhere. Since inspection and maintenance are amongst the few cost factors, which could be actively influenced in the short term, and in combination with the recent regulatory fundamental changes (e.g. PED) yielding to considerably greater responsibilities for the operator of a plant, also the demand for documentation and comprehensibility of measures will increase. (orig.)

  10. The safety monitor and RCM workstation as complementary tools in risk based maintenance optimization

    International Nuclear Information System (INIS)

    Rawson, P.D.

    2000-01-01

    Reliability Centred Maintenance (RCM) represents a proven technique for rendering maintenance activities safer, more effective, and less expensive, in terms of systems unavailability and resource management. However, it is believed that RCM can be enhanced by the additional consideration of operational plant risk. This paper discusses how two computer-based tools, i.e., the RCM Workstation and the Safety Monitor, can complement each other in helping to create a living preventive maintenance strategy. (author)

  11. Monitoring based maintenance utilizing actual stress sensory technology

    Science.gov (United States)

    Sumitro, Sunaryo; Kurokawa, Shoji; Shimano, Keiji; Wang, Ming L.

    2005-06-01

    In recent years, many infrastructures have been deteriorating. In order to maintain sustainability of those infrastructures which have significant influence on social lifelines, economical and rational maintenance management should be carried out to evaluate the life cycle cost (LCC). The development of structural health monitoring systems, such as deriving evaluation techniques for the field structural condition of existing structures and identification techniques for the significant engineering properties of new structures, can be considered as the first step in resolving the above problem. New innovative evaluation methods need to be devised to identify the deterioration of infrastructures, e.g. steel tendons, cables in cable-stayed bridges and strands embedded in pre- or post-tensioned concrete structures. One of the possible solutions that show 'AtoE' characteristics, i.e., (a)ccuracy, (b)enefit, (c)ompendiousness, (d)urability and (e)ase of operation, elasto-magnetic (EM) actual stress sensory technology utilizing the sensitivity of incremental magnetic permeability to stress change, has been developed. Numerous verification tests on various steel materials have been conducted. By comparing with load cell, strain gage and other sensory technology measurement results, the actual stresses of steel tendons in a pre-stressed concrete structure at the following stages have been thoroughly investigated: (i) pre-stress change due to set-loss (anchorage slippage) at the tendon fixation stage; (ii) pre-stress change due to the tendon relaxation stage; (iii) concrete creep and shrinkage at the long term pre-stressing stage; (iv) pre-stress change in the cyclic fatigue loading stage; and (v) pre-stress change due to the re-pre-stress setting stage. As the result of this testing, it is confirmed that EM sensory technology enables one to measure actual stress in steel wire, strands and steel bars precisely without destroying the polyethylene covering sheath and enables

  12. Multi-criteria weighted order based maintenance decision making

    NARCIS (Netherlands)

    Dhanisetty, V.S.V.; Verhagen, W.J.C.; Curran, R.

    2017-01-01

    Decision making in daily maintenance requires consideration of multiple factors. The importance of each of the factors fluctuates depending on the repair scenario and the needs of the maintainer. In order to include the prioritisation of multiple criteria, a weighted decision making model is

  13. Research of nuclear power plant in-service maintenance based on virtual reality

    International Nuclear Information System (INIS)

    Wang Yong; Kuang Weijun

    2015-01-01

    This paper presents a method of constructing nuclear power plant in-service maintenance virtual simulation scene and virtual maintenance process. Taking air baffles dismantling process of CAP1400(China Advanced Passive 1400) nuclear power plant as an instance, this paper discusses ergonomics, space analysis, time assessment based on virtual reality in the process of in-service maintenance. It demonstrates the advantage of using VR technology to design and verify in-service maintenance process of nuclear power plant compared to the conventional way. (author)

  14. Analytical method for optimization of maintenance policy based on available system failure data

    International Nuclear Information System (INIS)

    Coria, V.H.; Maximov, S.; Rivas-Dávalos, F.; Melchor, C.L.; Guardado, J.L.

    2015-01-01

    An analytical optimization method for preventive maintenance (PM) policy with minimal repair at failure, periodic maintenance, and replacement is proposed for systems with historical failure time data influenced by a current PM policy. The method includes a new imperfect PM model based on Weibull distribution and incorporates the current maintenance interval T 0 and the optimal maintenance interval T to be found. The Weibull parameters are analytically estimated using maximum likelihood estimation. Based on this model, the optimal number of PM and the optimal maintenance interval for minimizing the expected cost over an infinite time horizon are also analytically determined. A number of examples are presented involving different failure time data and current maintenance intervals to analyze how the proposed analytical optimization method for periodic PM policy performances in response to changes in the distribution of the failure data and the current maintenance interval. - Highlights: • An analytical optimization method for preventive maintenance (PM) policy is proposed. • A new imperfect PM model is developed. • The Weibull parameters are analytically estimated using maximum likelihood. • The optimal maintenance interval and number of PM are also analytically determined. • The model is validated by several numerical examples

  15. 14 CFR 119.47 - Maintaining a principal base of operations, main operations base, and main maintenance base...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Maintaining a principal base of operations, main operations base, and main maintenance base; change of address. 119.47 Section 119.47 Aeronautics... Under Part 121 or Part 135 of This Chapter § 119.47 Maintaining a principal base of operations, main...

  16. Development of maintenance tools based on tribology for nuclear power plant

    International Nuclear Information System (INIS)

    Iwai, Yoshiro; Honda, Tomomi; Yoshinaga, Shigeki

    2007-01-01

    Many tribological problems occur in the maintenance of nuclear power plants. In this paper, we introduced our developed maintenance tools based on tribology such as a particle counter and wear sensors. Their principals were shown briefly and their usefulness was clarified by the experiments on monitoring of wear. (author)

  17. Maintenance of algal endosymbionts in Paramecium bursaria: a simple model based on population dynamics.

    Science.gov (United States)

    Iwai, Sosuke; Fujiwara, Kenji; Tamura, Takuro

    2016-09-01

    Algal endosymbiosis is widely distributed in eukaryotes including many protists and metazoans, and plays important roles in aquatic ecosystems, combining phagotrophy and phototrophy. To maintain a stable symbiotic relationship, endosymbiont population size in the host must be properly regulated and maintained at a constant level; however, the mechanisms underlying the maintenance of algal endosymbionts are still largely unknown. Here we investigate the population dynamics of the unicellular ciliate Paramecium bursaria and its Chlorella-like algal endosymbiont under various experimental conditions in a simple culture system. Our results suggest that endosymbiont population size in P. bursaria was not regulated by active processes such as cell division coupling between the two organisms, or partitioning of the endosymbionts at host cell division. Regardless, endosymbiont population size was eventually adjusted to a nearly constant level once cells were grown with light and nutrients. To explain this apparent regulation of population size, we propose a simple mechanism based on the different growth properties (specifically the nutrient requirements) of the two organisms, and based from this develop a mathematical model to describe the population dynamics of host and endosymbiont. The proposed mechanism and model may provide a basis for understanding the maintenance of algal endosymbionts. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Rock mechanical conditions at the Aespoe HRL. A study of the correlation between geology, tunnel maintenance and tunnel shape

    International Nuclear Information System (INIS)

    Andersson, Christer; Soederhaell, Joergen

    2001-12-01

    Maintenance records including scaling, shotcreting and bolting have been kept since the excavation start of Aespoe HRL 1990 together with records of groundwater flow and all other activities taking place in the tunnels. When the facility was constructed one objective was to limit the rock support as much as possible. The reason for this was that it should be possible to go back and easily study the exposed rock surface. Support during the operational phase has only been carried out where and when necessary. This type of maintenance and its location is documented in the digital database each time. The maintenance records have been compiled and areas requiring more maintenance than average noted. An interview has also been held with one of the miners conducting scaling and bolting in the tunnel. His experiences together with the study of the database maintenance records led to the selection of certain areas in the tunnel to be studied by numerical modelling. The probable reason for the need of additional maintenance in all areas, not only these numerically modelled, has been investigated. Almost all maintenance in the main tunnel both during construction and the operational phase has been located in the widened curves of the access tunnel. The maintenance is also located in areas containing veins or intrusions of Smaaland granite or fine-grained granite. These areas are often located in fracture zones of different sizes or show an increasing fracture frequency. The areas numerically modelled indicate stress concentrations or unloaded stress conditions. The stress concentrations are created by the geometry of the niches and side-tunnels in relation to the in situ stress field. The angle between the tunnel and the major principal stress has an impact on the need for maintenance. The areas with the largest angles towards the principal stress direction need more maintenance than the areas almost parallel to the major principal stress direction. The maintenance work in

  19. Identification of National Road Maintenance Needs Based on Strategic Plan of Directorate General of Bina Marga (2015-2019

    Directory of Open Access Journals (Sweden)

    Rizky Ardhiarini

    2016-05-01

    Full Text Available The enhancement of connectivity between the main corridors of the economy in South Sumatera, as a purpose of the Strategic Plan of Directorate General Bina Marga and also an objective of MP3EI, Master Plan for Acceleration and expansion of Indonesia's Economic Development which is an ambitious plan by the Indonesian government to accelerate the realization of becoming a developed country would be able to achieve on the requirement of good condition on performance and pavement. In order to support the optimal condition of the road, the identification of road management was conducted to determine the necessity of road maintenance based on technical conditions and importance level of development of the road traversed. The management program proposed is expected to be used as a baseline in determining the maintenance of the road network in South Sumatera from 2015 until 2019. This research used Multi-criteria Analysis (MCA method, which consists of: (1 road network performance, covering width of roadways, traffic flow, V/C ratio, travel speed and travel time of the vehicle, and (2 pavement condition, with IRI, SDI, and the proportion of good pavement condition as a parameter. Multi-criteria analysis used combined road condition assessment score and importance level of development of the area traversed by. This analysis was conducted from 2015 until 2019. The research concluded that maintenance necessity in 2015 were dominated by routine maintenance (95.86% of the total length, then in 2016 until 2019 the needs were dominated by routine maintenance (near 100% of the total length. As the maintenance applied, a vast amount of total road length fulfilled as an achievement target. The results are follows: (a 100% with width of roadways ≥ 7 meter, (b 97.83% with V/C ratio  60km/hour, (d 17.32% with travel time (TT 95%, (f 90.37% with IRI < 4 m/Km, and (g 91.59 with SDI < 50. Yet with the achievement of 100% of total road length with a

  20. Regulatory oversight of maintenance activities at nuclear power plants

    International Nuclear Information System (INIS)

    Pape, M.

    1997-01-01

    Regulation of nuclear safety in the UK is based on monitoring of compliance with licence conditions. This paper discusses legislation aspects, license conditions, license requirements for maintenance and maintenance activities in the UK. It also addresses the regulator utility interaction, the regulatory inspection of maintenance and the trends in maintenance. (author)

  1. The virtual maintenance system: a computer-based support tool for robust design, product monitoring, fault diagnosis and maintenance planning

    NARCIS (Netherlands)

    van Houten, Frederikus J.A.M.; Kimura, F.

    2000-01-01

    Digital (geometric) product models can be used for maintainability analysis and maintenance planning. It is not feasible to build digital product models for maintenance purposes only, but if a digital product model is available, it may be used to support many maintenance-related engineering tasks.

  2. Knowledge-based machine indexing from natural language text: Knowledge base design, development, and maintenance

    Science.gov (United States)

    Genuardi, Michael T.

    1993-01-01

    One strategy for machine-aided indexing (MAI) is to provide a concept-level analysis of the textual elements of documents or document abstracts. In such systems, natural-language phrases are analyzed in order to identify and classify concepts related to a particular subject domain. The overall performance of these MAI systems is largely dependent on the quality and comprehensiveness of their knowledge bases. These knowledge bases function to (1) define the relations between a controlled indexing vocabulary and natural language expressions; (2) provide a simple mechanism for disambiguation and the determination of relevancy; and (3) allow the extension of concept-hierarchical structure to all elements of the knowledge file. After a brief description of the NASA Machine-Aided Indexing system, concerns related to the development and maintenance of MAI knowledge bases are discussed. Particular emphasis is given to statistically-based text analysis tools designed to aid the knowledge base developer. One such tool, the Knowledge Base Building (KBB) program, presents the domain expert with a well-filtered list of synonyms and conceptually-related phrases for each thesaurus concept. Another tool, the Knowledge Base Maintenance (KBM) program, functions to identify areas of the knowledge base affected by changes in the conceptual domain (for example, the addition of a new thesaurus term). An alternate use of the KBM as an aid in thesaurus construction is also discussed.

  3. Global optimization of maintenance and surveillance testing based on reliability and probabilistic safety assessment. Research project

    International Nuclear Information System (INIS)

    Martorell, S.; Serradell, V.; Munoz, A.; Sanchez, A.

    1997-01-01

    Background, objective, scope, detailed working plan and follow-up and final product of the project ''Global optimization of maintenance and surveillance testing based on reliability and probabilistic safety assessment'' are described

  4. Developing Mobile- and BIM-Based Integrated Visual Facility Maintenance Management System

    Directory of Open Access Journals (Sweden)

    Yu-Cheng Lin

    2013-01-01

    Full Text Available Facility maintenance management (FMM has become an important topic for research on the operation phase of the construction life cycle. Managing FMM effectively is extremely difficult owing to various factors and environments. One of the difficulties is the performance of 2D graphics when depicting maintenance service. Building information modeling (BIM uses precise geometry and relevant data to support the maintenance service of facilities depicted in 3D object-oriented CAD. This paper proposes a new and practical methodology with application to FMM using BIM technology. Using BIM technology, this study proposes a BIM-based facility maintenance management (BIMFMM system for maintenance staff in the operation and maintenance phase. The BIMFMM system is then applied in selected case study of a commercial building project in Taiwan to verify the proposed methodology and demonstrate its effectiveness in FMM practice. Using the BIMFMM system, maintenance staff can access and review 3D BIM models for updating related maintenance records in a digital format. Moreover, this study presents a generic system architecture and its implementation. The combined results demonstrate that a BIMFMM-like system can be an effective visual FMM tool.

  5. Are air-conditioning maintenance personnel at increased risk of Legionellosis?

    Science.gov (United States)

    Goldman, W D; Marr, J S

    1980-07-01

    We surveyed by use of medical questionnaires and blood tests 21 maintenance workers involved with cleaning and servicing cooling towers and evaporative condensers at a large company to determine the frequency of pneumonia and antibody levels against Legionella pneumophila serogroup 1. The 21 high-risk workers were compared with 27 low-risk workers, persons who were not directly involved in service or maintenance for the company. The overall prevalence of titers greater than or equal to 128 for the 21 high-risk workers was 19.0% compared with 22.2% for the low-risk group. There were no significant differences in the history of pneumonia between these groups. Possible explanations for these findings are discussed.

  6. Addressing imperfect maintenance modelling uncertainty in unavailability and cost based optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Ana [Department of Statistics and Operational Research, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain); Carlos, Sofia [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain); Martorell, Sebastian [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain)], E-mail: smartore@iqn.upv.es; Villanueva, Jose F. [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera, s/n, 46071 Valencia (Spain)

    2009-01-15

    Optimization of testing and maintenance activities performed in the different systems of a complex industrial plant is of great interest as the plant availability and economy strongly depend on the maintenance activities planned. Traditionally, two types of models, i.e. deterministic and probabilistic, have been considered to simulate the impact of testing and maintenance activities on equipment unavailability and the cost involved. Both models present uncertainties that are often categorized as either aleatory or epistemic uncertainties. The second group applies when there is limited knowledge on the proper model to represent a problem, and/or the values associated to the model parameters, so the results of the calculation performed with them incorporate uncertainty. This paper addresses the problem of testing and maintenance optimization based on unavailability and cost criteria and considering epistemic uncertainty in the imperfect maintenance modelling. It is framed as a multiple criteria decision making problem where unavailability and cost act as uncertain and conflicting decision criteria. A tolerance interval based approach is used to address uncertainty with regard to effectiveness parameter and imperfect maintenance model embedded within a multiple-objective genetic algorithm. A case of application for a stand-by safety related system of a nuclear power plant is presented. The results obtained in this application show the importance of considering uncertainties in the modelling of imperfect maintenance, as the optimal solutions found are associated with a large uncertainty that influences the final decision making depending on, for example, if the decision maker is risk averse or risk neutral.

  7. Addressing imperfect maintenance modelling uncertainty in unavailability and cost based optimization

    International Nuclear Information System (INIS)

    Sanchez, Ana; Carlos, Sofia; Martorell, Sebastian; Villanueva, Jose F.

    2009-01-01

    Optimization of testing and maintenance activities performed in the different systems of a complex industrial plant is of great interest as the plant availability and economy strongly depend on the maintenance activities planned. Traditionally, two types of models, i.e. deterministic and probabilistic, have been considered to simulate the impact of testing and maintenance activities on equipment unavailability and the cost involved. Both models present uncertainties that are often categorized as either aleatory or epistemic uncertainties. The second group applies when there is limited knowledge on the proper model to represent a problem, and/or the values associated to the model parameters, so the results of the calculation performed with them incorporate uncertainty. This paper addresses the problem of testing and maintenance optimization based on unavailability and cost criteria and considering epistemic uncertainty in the imperfect maintenance modelling. It is framed as a multiple criteria decision making problem where unavailability and cost act as uncertain and conflicting decision criteria. A tolerance interval based approach is used to address uncertainty with regard to effectiveness parameter and imperfect maintenance model embedded within a multiple-objective genetic algorithm. A case of application for a stand-by safety related system of a nuclear power plant is presented. The results obtained in this application show the importance of considering uncertainties in the modelling of imperfect maintenance, as the optimal solutions found are associated with a large uncertainty that influences the final decision making depending on, for example, if the decision maker is risk averse or risk neutral

  8. PRM-based patterns for knowledge formalisation of industrial systems to support maintenance strategies assessment

    International Nuclear Information System (INIS)

    Medina-Oliva, G.; Weber, P.; Iung, B.

    2013-01-01

    The production system and its maintenance system must be now developed on “system thinking” paradigm in order to guarantee that Key Performance Indicators (KPI) will be optimized all along the production system (operation) life. In a recursive way, maintenance system engineering has to integrate also KPI considerations with regards to its own enabling systems. Thus this paper develops a system-based methodology wherein a set of KPIs is computed in order to verify if the objectives of the production and maintenance systems are satisfied. In order to help the decision-making process for maintenance managers, a “unified” generic model have been developed. This model integrates (a) the interactions of the maintenance system with its enabling systems, (b) the impact of the maintenance strategies through the computation of some key performance indicators, and (c) different kinds of knowledge regarding the maintenance system and the system of interest, including quantitative and qualitative knowledge. This methodology is based on an executable unified model built with Probabilistic Relational Model (PRM). PRM allows a modular representation and inferences computation of large size models. The methodology added-value is shown on a test-bench

  9. Application of genetic algorithms to the maintenance scheduling optimization in a nuclear system basing on reliability

    International Nuclear Information System (INIS)

    Lapa, Celso M. Franklin; Pereira, Claudio M.N.A.; Mol, Antonio C. de Abreu

    1999-01-01

    This paper presents a solution based on genetic algorithm and probabilistic safety analysis that can be applied in the optimization of the preventive maintenance politic of nuclear power plant safety systems. The goal of this approach is to improve the average availability of the system through the optimization of the preventive maintenance scheduling politic. The auxiliary feed water system of a two loops pressurized water reactor is used as a sample case, in order to demonstrate the effectiveness of the proposed method. The results, when compared to those obtained by some standard maintenance politics, reveal quantitative gains and operational safety levels. (author)

  10. A maintenance policy for two-unit parallel systems based on imperfect monitoring information

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Anne [Department Genie des Systems Industiels (GSI), Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes, Cedex (France)]. E-mail: anne.barros@utt.fr; Berenguer, Christophe [Department Genie des Systems Industiels (GSI), Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes, Cedex (France); Grall, Antoine [Department Genie des Systems Industiels (GSI), Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes, Cedex (France)

    2006-02-01

    In this paper a maintenance policy is optimised for a two-unit system with a parallel structure and stochastic dependences. Monitoring problems are taken into account in the optimisation scheme: the failure time of each unit can be not detected with a given probability. Conditions on the system parameters (unit failure rates) and on the non-detection probabilities must be verified to make the optimisation scheme valid. These conditions are clearly identified. Numerical experiments allow to show the relevance of taking into account monitoring problems in the maintenance model.

  11. A maintenance policy for two-unit parallel systems based on imperfect monitoring information

    International Nuclear Information System (INIS)

    Barros, Anne; Berenguer, Christophe; Grall, Antoine

    2006-01-01

    In this paper a maintenance policy is optimised for a two-unit system with a parallel structure and stochastic dependences. Monitoring problems are taken into account in the optimisation scheme: the failure time of each unit can be not detected with a given probability. Conditions on the system parameters (unit failure rates) and on the non-detection probabilities must be verified to make the optimisation scheme valid. These conditions are clearly identified. Numerical experiments allow to show the relevance of taking into account monitoring problems in the maintenance model

  12. Structural maintenance planning based on historical data of corroded deck plates of tankers

    International Nuclear Information System (INIS)

    Garbatov, Y.; Guedes Soares, C.

    2009-01-01

    A probabilistic maintenance and repair analysis of tanker deck plates subjected to general corrosion is presented. The decisions about when to perform maintenance and repair on the structure are studied. Different practical scenarios are analyzed and optimum repair times are proposed. The optimum repair age and intervals are defined based on the statistical analysis of operational data using the Weibull model and some assumptions about the inspection and time needed for repair. The total cost is calculated in normalized form.

  13. A Costing Analysis for Decision Making Grid Model in Failure-Based Maintenance

    Directory of Open Access Journals (Sweden)

    Burhanuddin M. A.

    2011-01-01

    Full Text Available Background. In current economic downturn, industries have to set good control on production cost, to maintain their profit margin. Maintenance department as an imperative unit in industries should attain all maintenance data, process information instantaneously, and subsequently transform it into a useful decision. Then act on the alternative to reduce production cost. Decision Making Grid model is used to identify strategies for maintenance decision. However, the model has limitation as it consider two factors only, that is, downtime and frequency of failures. We consider third factor, cost, in this study for failure-based maintenance. The objective of this paper is to introduce the formulae to estimate maintenance cost. Methods. Fish bone analysis conducted with Ishikawa model and Decision Making Grid methods are used in this study to reveal some underlying risk factors that delay failure-based maintenance. The goal of the study is to estimate the risk factor that is, repair cost to fit in the Decision Making Grid model. Decision Making grid model consider two variables, frequency of failure and downtime in the analysis. This paper introduces third variable, repair cost for Decision Making Grid model. This approaches give better result to categorize the machines, reduce cost, and boost the earning for the manufacturing plant. Results. We collected data from one of the food processing factories in Malaysia. From our empirical result, Machine C, Machine D, Machine F, and Machine I must be in the Decision Making Grid model even though their frequency of failures and downtime are less than Machine B and Machine N, based on the costing analysis. The case study and experimental results show that the cost analysis in Decision Making Grid model gives more promising strategies in failure-based maintenance. Conclusions. The improvement of Decision Making Grid model for decision analysis with costing analysis is our contribution in this paper for

  14. Feature-based and object-based attention orientation during short-term memory maintenance.

    Science.gov (United States)

    Ku, Yixuan

    2015-12-01

    Top-down attention biases the short-term memory (STM) processing at multiple stages. Orienting attention during the maintenance period of STM by a retrospective cue (retro-cue) strengthens the representation of the cued item and improves the subsequent STM performance. In a recent article, Backer et al. (Backer KC, Binns MA, Alain C. J Neurosci 35: 1307-1318, 2015) extended these findings from the visual to the auditory domain and combined electroencephalography to dissociate neural mechanisms underlying feature-based and object-based attention orientation. Both event-related potentials and neural oscillations explained the behavioral benefits of retro-cues and favored the theory that feature-based and object-based attention orientation were independent. Copyright © 2015 the American Physiological Society.

  15. Risk-based equipment removal guide for on-line maintenance at PSE ampersand G

    International Nuclear Information System (INIS)

    Knoll, A.; Smith, C.; Pollock, J.

    1995-01-01

    On-line maintenance plays an important role in achieving safe and reliable power generation in a nuclear power plant. However, maintenance, if not properly planned and performed, may also be an important contributor to plant risk. Therefore, plant-specific procedures are needed for equipment removal from service to enhance the benefits of on-line maintenance and minimize the risks involved. The problem is to identify and implement the most effective on-line maintenance policy in the form of a proceduralized guide to assure plant safety under various operation and maintenance constraints. This paper presents a methodology to develop plant-specific on-line maintenance strategies and acceptance criteria using a multivariate safety approach based on risk assessment. Based on plant-specific data as modeled in the individual plant evaluation (IPE) and the updated probabilistic safety assessment (PSA), the risk-based methodology is currently being applied to the development of proceduralized equipment removal guides at Hope Creek and Salem units 1 and 2 of Public Service Electric and Gas Company (PSE ampersand G)

  16. Consistency maintenance for constraint in role-based access control model

    Institute of Scientific and Technical Information of China (English)

    韩伟力; 陈刚; 尹建伟; 董金祥

    2002-01-01

    Constraint is an important aspect of role-based access control and is sometimes argued to be the principal motivation for role-based access control (RBAC). But so far few authors have discussed consistency maintenance for constraint in RBAC model. Based on researches of constraints among roles and types of inconsistency among constraints, this paper introduces corresponding formal rules, rule-based reasoning and corresponding methods to detect, avoid and resolve these inconsistencies. Finally, the paper introduces briefly the application of consistency maintenance in ZD-PDM, an enterprise-oriented product data management (PDM) system.

  17. Computer-Based Simulations for Maintenance Training: Current ARI Research. Technical Report 544.

    Science.gov (United States)

    Knerr, Bruce W.; And Others

    Three research efforts that used computer-based simulations for maintenance training were in progress when this report was written: Game-Based Learning, which investigated the use of computer-based games to train electronics diagnostic skills; Human Performance in Fault Diagnosis Tasks, which evaluated the use of context-free tasks to train…

  18. Development of a knowledge-based information management system for plant maintenance

    International Nuclear Information System (INIS)

    Yim, Hyung Sang; Park, Young Jae; Lee, Sang Min; Choi, Jae Boong; Kim, Young Jin; Roh, Eun Chul; Lee, Byung Ine

    2003-01-01

    Recently, the importance of Plant Maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as Risk-Based Inspection(RBI), Fitness For Service guidelines(FFS), Plant Lifecycle Management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance

  19. Development of a knowledge-based information management system for plant maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Hyung Sang; Park, Young Jae; Lee, Sang Min; Choi, Jae Boong; Kim, Young Jin [Sungkyunkwan Univ., Seoul (Korea, Republic of); Roh, Eun Chul; Lee, Byung Ine [Pohang Iron and Steel Company, Pohang (Korea, Republic of)

    2003-07-01

    Recently, the importance of Plant Maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as Risk-Based Inspection(RBI), Fitness For Service guidelines(FFS), Plant Lifecycle Management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.

  20. Dynamic decision-making for reliability and maintenance analysis of manufacturing systems based on failure effects

    Science.gov (United States)

    Zhang, Ding; Zhang, Yingjie

    2017-09-01

    A framework for reliability and maintenance analysis of job shop manufacturing systems is proposed in this paper. An efficient preventive maintenance (PM) policy in terms of failure effects analysis (FEA) is proposed. Subsequently, reliability evaluation and component importance measure based on FEA are performed under the PM policy. A job shop manufacturing system is applied to validate the reliability evaluation and dynamic maintenance policy. Obtained results are compared with existed methods and the effectiveness is validated. Some vague understandings for issues such as network modelling, vulnerabilities identification, the evaluation criteria of repairable systems, as well as PM policy during manufacturing system reliability analysis are elaborated. This framework can help for reliability optimisation and rational maintenance resources allocation of job shop manufacturing systems.

  1. Research on gesture recognition of augmented reality maintenance guiding system based on improved SVM

    Science.gov (United States)

    Zhao, Shouwei; Zhang, Yong; Zhou, Bin; Ma, Dongxi

    2014-09-01

    Interaction is one of the key techniques of augmented reality (AR) maintenance guiding system. Because of the complexity of the maintenance guiding system's image background and the high dimensionality of gesture characteristics, the whole process of gesture recognition can be divided into three stages which are gesture segmentation, gesture characteristic feature modeling and trick recognition. In segmentation stage, for solving the misrecognition of skin-like region, a segmentation algorithm combing background mode and skin color to preclude some skin-like regions is adopted. In gesture characteristic feature modeling of image attributes stage, plenty of characteristic features are analyzed and acquired, such as structure characteristics, Hu invariant moments features and Fourier descriptor. In trick recognition stage, a classifier based on Support Vector Machine (SVM) is introduced into the augmented reality maintenance guiding process. SVM is a novel learning method based on statistical learning theory, processing academic foundation and excellent learning ability, having a lot of issues in machine learning area and special advantages in dealing with small samples, non-linear pattern recognition at high dimension. The gesture recognition of augmented reality maintenance guiding system is realized by SVM after the granulation of all the characteristic features. The experimental results of the simulation of number gesture recognition and its application in augmented reality maintenance guiding system show that the real-time performance and robustness of gesture recognition of AR maintenance guiding system can be greatly enhanced by improved SVM.

  2. A study on human performance enhancement plan in maintenance field by survey on actual condition of human performance tools - 15035

    International Nuclear Information System (INIS)

    Park, J.; Jeong, H.; Kim, Y.

    2015-01-01

    Human errors in nuclear power plant are one of the important factors that may cause reactor trip. Most operating companies of nuclear power plants manage human factor systematically through tools like HPES (Human Performance Enhancement), PSR (Periodic Safety Review), OE (Operating Experience), human performance tools, safety culture assessment and CAP (Corrective Action Program). But human factors are managed passively in maintenance field, because maintenance works are carrying out by partner companies. KHNP also contracts the maintenance work to the partner companies, and advise them to use human performance tools. But the actual condition on partner companies has not been surveyed. This paper suggests some plans that can improve human performance by analyzing the opinion of partner company employees about the causes and solutions of human errors, by analyzing utilization of human performance tools and by comparing the results of the partner companies survey with the results of the operating company survey. The survey is conducted to 3 partner companies by similar contents and categories in order to compare partner company with operating company, and the main analysis fields are the following: -1) Level of understanding and utilization of the human performance tools, -2) Difficulties of applying the human performance tools, -3) Level of employee's training (or education) in the use of the human performance tools, and -4) Root causes of human errors and countermeasures. (authors)

  3. Consistency maintenance for constraint in role-based access control model

    Institute of Scientific and Technical Information of China (English)

    韩伟力; 陈刚; 尹建伟; 董金祥

    2002-01-01

    Constraint is an important aspect of role-based access control and is sometimes argued to be the principal motivation for role-based access control (RBAC). But so far'few authors have discussed consistency maintenance for constraint in RBAC model. Based on researches of constraints among roles and types of inconsistency among constraints, this paper introduces correaponding formal rules, rulebased reasoning and corresponding methods to detect, avoid and resolve these inconsistencies. Finally,the paper introduces briefly the application of consistency maintenance in ZD-PDM, an enterprise-ori-ented product data management (PDM) system.

  4. Comparison of the effects of two anesthesia maintenance methods by remifentanil or halothane on endoscopic sinus surgery condition

    Directory of Open Access Journals (Sweden)

    Seyed mojtaba Karimi

    2008-07-01

    Full Text Available Introduction: Endoscopic surgery is a new standard method of treatment for chronic sinusitis. During this operation even small amount of bleeding may reduce the visual field of surgeon significantly and make the procedure troublesome. In this study we have compared the operative condition between patients who receive either remifentanil or halothane for general anesthesia. Materials and Methods: Endoscopic sinus surgery was performed in 60 patents. Pre- medication was done by fentanil and midazolam and induction was done by propofol and atracurium. Halothane or remifentanil was used in two groups of patients respectively for anesthesia maintenance. Monitoring was performed during anesthesia. Bleeding volume was measured and operation field condition was assessed by the surgeon. Results: Personal characteristics such as age and sex were the same in both groups. Intra- operative systolic blood pressures was significantly lower in remifentanil group but diastolic and mean blood pressure and heart rate didn’t change after induction and during maintenance in both groups. Recovery time in remifentanil group was also significantly shorter than halothane group. Finally bleeding volume was lower and operation field condition was better significantly in remifentanil group. Conclusion: Remifentanil is a good choice to maintain an ideal anesthesia for endoscopic sinus surgery.    

  5. Routine maintenance: safety term based work selection; Selecao de trabalho baseado no prazo seguro

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Albair de; Filho, Antnio S.; Brendler, Fabiano E.; Adamatti, Gilberto A.; Naruto, Itiro; Araujo, Luiz C.F.; Puerari, Roberto [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    This work has objective to present the experience of improvement of routine maintenance system in some refineries of the PETROBRAS system, with the purpose to increase the efficiency in the Industrial Maintenance Management (cost), Utilization and HSE (Health, Safety and Environment), key of success of a petroleum company. The new system is based on the implantation of the culture of work selection in the safe period, through elaboration of new maintenance procedure, with emphasis in decisions shared between Operation and Maintenance Team, resulting in reduction of emergencies, making possible contract of services of maintenance for packages and improved allocation of resources. This work treat about improvement of the system in use, in view of that it has already taken in consideration the consequence of fail in the maintenance with participation of the operators. Besides of these challenge, this modification was made without causing riots in the process of implantation of SAP. As main result, financial profits had got better of resources with increase of safety, considering that they are analyzed in a way it that systematized potential risks. (author)

  6. PERFORMANCE-BASED CONTRACTING IN CONSTRUCTION PHASE AND MAINTENANCE PHASE OF PAVEMENT

    Science.gov (United States)

    Yoshida, Takeshi

    Performance-based contracting for pavement in Japan started as performance warranties in construction phase, in 1999. Recently, road agencies have recognized the applicability of this type of contracting in outsourcing of maintenance activities. The objectives of this study are to clarify the issues of performance specifying in construction phase and maintenance phase of pavement, and to propose measures to be taken. This paper, with the recognition that the life of each pavement depends on performance standards for various attributes, reviews domestic and foreign examples of performance-based contracting. A performance standard based on the average of current practices can enhance product quality and service life with a warranty contract. Repair thresholds and response time for each deficiency should be considered as performance standards in maintenance phase.

  7. A risk-based model for maintenance decision support of civil structures using RAMS

    NARCIS (Netherlands)

    Viana Da Rocha, T. C.; Stipanovic, I.; Hartmann, A.; Bakker, J.

    2017-01-01

    As a cornerstone of transportation asset management, risk-based approaches have been used to support maintenance decisions of civil structures. However, ambiguous and subjective risk criteria and inconsistency on the use of risk-based approaches can lead to a fuzzy understanding of the risks

  8. 49 CFR Appendix E to Part 238 - General Principles of Reliability-Based Maintenance Programs

    Science.gov (United States)

    2010-10-01

    ... STANDARDS Pt. 238, App. E Appendix E to Part 238—General Principles of Reliability-Based Maintenance... 49 Transportation 4 2010-10-01 2010-10-01 false General Principles of Reliability-Based... the design level of safety and reliability of the equipment; (2) To restore safety and reliability to...

  9. Maintenance of polygenic sex determination in a fluctuating environment: an individual-based model.

    Science.gov (United States)

    Bateman, A W; Anholt, B R

    2017-05-01

    R. A. Fisher predicted that individuals should invest equally in offspring of both sexes, and that the proportion of males and females produced (the primary sex ratio) should evolve towards 1:1 when unconstrained. For many species, sex determination is dependent on sex chromosomes, creating a strong tendency for balanced sex ratios, but in other cases, multiple autosomal genes interact to determine sex. In such cases, the maintenance of multiple sex-determining alleles at multiple loci and the consequent among-family variability in sex ratios presents a puzzle, as theory predicts that such systems should be unstable. Theory also predicts that environmental influences on sex can complicate outcomes of genetic sex determination, and that population structure may play a role. Tigriopus californicus, a copepod that lives in splash-pool metapopulations and exhibits polygenic and environment-dependent sex determination, presents a test case for relevant theory. We use this species as a model for parameterizing an individual-based simulation to investigate conditions that could maintain polygenic sex determination. We find that metapopulation structure can delay the degradation of polygenic sex determination and that periods of alternating frequency-dependent selection, imposed by seasonal fluctuations in environmental conditions, can maintain polygenic sex determination indefinitely. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  10. Risk-Based Maintenance Assessment in the Manufacturing Industry: Minimisation of Suboptimal Prioritisation

    Directory of Open Access Journals (Sweden)

    Ratnayake R.M. Chandima

    2017-03-01

    Full Text Available Manufacturing firms continuously strive to increase the efficiency and effectiveness in the maintenance management processes. Focus is placed on eliminating the unexpected failures which cause unnecessary costs and the production losses. Risk-based maintenance (RBM strategies enable to address the above through the identification of probability and consequences of potential failures whilst providing a way for prioritisation of maintenance actions based on the risk of possible failures. Such prioritisations enable to identify the optimal maintenance strategy, intervals of maintenance tasks, and optimal level of spare parts inventory. However, the risk assessment activities are performed with the support of a risk matrix. Suboptimal classifications and/or prioritisations arise due to the inherent nature of the risk matrix. This is caused by the fact that there are no means to incorporate actual circumstances at the boundary of the input ranges or at the levels of linguistic data and risk categories. In this paper, a risk matrix is first developed in collaboration with one of the manufacturing firms in Poland. Then, it illustrates the use of fuzzy logic for minimisation of suboptimal prioritisation and/or classifications using a fuzzy inference system (FIS together with illustrative membership functions and a rule base. Finally, an illustrative risk assessment is also demonstrated to illustrate the methodology.

  11. A preventive maintenance policy based on dependent two-stage deterioration and external shocks

    International Nuclear Information System (INIS)

    Yang, Li; Ma, Xiaobing; Peng, Rui; Zhai, Qingqing; Zhao, Yu

    2017-01-01

    This paper proposes a preventive maintenance policy for a single-unit system whose failure has two competing and dependent causes, i.e., internal deterioration and sudden shocks. The internal failure process is divided into two stages, i.e. normal and defective. Shocks arrive according to a non-homogeneous Poisson process (NHPP), leading to the failure of the system immediately. The occurrence rate of a shock is affected by the state of the system. Both an age-based replacement and finite number of periodic inspections are schemed simultaneously to deal with the competing failures. The objective of this study is to determine the optimal preventive replacement interval, inspection interval and number of inspections such that the expected cost per unit time is minimized. A case study on oil pipeline maintenance is presented to illustrate the maintenance policy. - Highlights: • A maintenance model based on two-stage deterioration and sudden shocks is developed. • The impact of internal system state on external shock process is studied. • A new preventive maintenance strategy combining age-based replacements and periodic inspections is proposed. • Postponed replacement of a defective system is provided by restricting the number of inspections.

  12. Bayesian based Prognostic Model for Predictive Maintenance of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Asgarpour, Masoud; Sørensen, John Dalsgaard

    2018-01-01

    The operation and maintenance costs of offshore wind farms can be significantly reduced if existing corrective actions are performed as efficient as possible and if future corrective actions are avoided by performing sufficient preventive actions. In this paper a prognostic model for degradation...... monitoring, fault prediction and predictive maintenance of offshore wind components is defined. The diagnostic model defined in this paper is based on degradation, remaining useful lifetime and hybrid inspection threshold models. The defined degradation model is based on an exponential distribution...

  13. Bayesian based Prognostic Model for Predictive Maintenance of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Asgarpour, Masoud; Sørensen, John Dalsgaard

    2018-01-01

    monitoring, fault prediction and predictive maintenance of offshore wind components is defined. The diagnostic model defined in this paper is based on degradation, remaining useful lifetime and hybrid inspection threshold models. The defined degradation model is based on an exponential distribution......The operation and maintenance costs of offshore wind farms can be significantly reduced if existing corrective actions are performed as efficient as possible and if future corrective actions are avoided by performing sufficient preventive actions. In this paper a prognostic model for degradation...

  14. Bayesian based Prognostic Model for Predictive Maintenance of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Asgarpour, Masoud

    2017-01-01

    monitoring, fault detection and predictive maintenance of offshore wind components is defined. The diagnostic model defined in this paper is based on degradation, remaining useful lifetime and hybrid inspection threshold models. The defined degradation model is based on an exponential distribution......The operation and maintenance costs of offshore wind farms can be significantly reduced if existing corrective actions are performed as efficient as possible and if future corrective actions are avoided by performing sufficient preventive actions. In this paper a prognostic model for degradation...

  15. Incorrect modeling of the failure process of minimally repaired systems under random conditions: The effect on the maintenance costs

    International Nuclear Information System (INIS)

    Pulcini, Gianpaolo

    2015-01-01

    This note investigates the effect of the incorrect modeling of the failure process of minimally repaired systems that operates under random environmental conditions on the costs of a periodic replacement maintenance. The motivation of this paper is given by a recently published paper, where a wrong formulation of the expected cost for unit time under a periodic replacement policy is obtained. This wrong formulation is due to the incorrect assumption that the intensity function of minimally repaired systems that operate under random conditions has the same functional form as the failure rate of the first failure time. This produced an incorrect optimization of the replacement maintenance. Thus, in this note the conceptual differences between the intensity function and the failure rate of the first failure time are first highlighted. Then, the correct expressions of the expected cost and of the optimal replacement period are provided. Finally, a real application is used to measure how severe can be the economical consequences caused by the incorrect modeling of the failure process.

  16. CANDU plant maintenance: Recent developments

    International Nuclear Information System (INIS)

    Charlebois, P.

    2000-01-01

    CANDU units have long been recognized for their exceptional safety and reliability. Continuing development in the maintenance area has played a key role in achieving this performance level. For over two decades, safety system availability has been monitored closely and system maintenance programs adjusted accordingly to maintain high levels of performance. But as the plants approach mid life in a more competitive environment and component aging becomes a concern, new methods and techniques are necessary. As a result, recent developments are moving the maintenance program largely from a corrective and preventive approach to predictive and condition based maintenance. The application of these techniques is also being extended to safety related systems. These recent developments include use of reliability centred methods to define system maintenance requirements and strategies. This approach has been implemented on a number of systems at Canadian CANDU plants with positive results. The pilot projects demonstrated that the overall maintenance effort remained relatively constant while the system performance improved. It was also possible to schedule some of the redundant component maintenance during plant operation without adverse impact on system availability. The probabilistic safety assessment was found to be useful in determining the safety implications of component outages. These new maintenance strategies are now making use of predictive and condition based maintenance techniques to anticipate equipment breakdown and schedule preventive maintenance as the need arises rather than time based. Some of these techniques include valve diagnostics, vibration monitoring, oil analysis, thermography. Of course, these tools and techniques must form part of an overall maintenance management system to ensure that maintenance becomes a living program. To facilitate this process and contain costs, new information technology tools are being introduced to provide system engineers

  17. BIM authoring for an image-based bridge maintenance system of existing cable-supported bridges

    Science.gov (United States)

    Dang, N. S.; Shim, C. S.

    2018-04-01

    Infrastructure nowadays is increasingly become the main backbone for the metropolitan development in general. Along with the rise of new facilities, the demand in term of maintenance for the existing bridges is indispensable. Recently, the terminology of “preventive maintenance” is not unfamiliar with the engineer, literally is the use of a bridge maintenance system (BMS) based on a BIM-oriented model. In this paper, the process of generating a BMS based on BIM model is introduced in detail. Data management for this BMS is separated into two modules: site inspection system and information management system. The noteworthy aspect of this model lays on the closed and automatic process of “capture image, generate the technical damage report, and upload/feedback to the BMS” in real-time. A pilot BMS system for a cable-supported bridge is presented which showed a good performance and potential to further development of preventive maintenance.

  18. Integrated vibration-based maintenance: an approach for continuous reduction in LCC. A case study

    Energy Technology Data Exchange (ETDEWEB)

    Najjar, B. [ER Konsult Utveckling AB, Vaexjoe (Sweden)

    1998-12-31

    The biggest thread in achieving and maintaining high equipment effectiveness can be stated as: whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery, and following defect development at an early stage to increase machine mean effective life and improve company`s economics. The effect of TQMain on LCC of machinery and company`s economics is discussed. A case study to reveal savings in maintenance cost when a vibration-based policy involved, is presented. Using TQMain, company`s economics can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes. (orig.) 14 refs.

  19. Integrated vibration-based maintenance: an approach for continuous reduction in LCC. A case study

    Energy Technology Data Exchange (ETDEWEB)

    Najjar, B [ER Konsult Utveckling AB, Vaexjoe (Sweden)

    1999-12-31

    The biggest thread in achieving and maintaining high equipment effectiveness can be stated as: whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery, and following defect development at an early stage to increase machine mean effective life and improve company`s economics. The effect of TQMain on LCC of machinery and company`s economics is discussed. A case study to reveal savings in maintenance cost when a vibration-based policy involved, is presented. Using TQMain, company`s economics can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes. (orig.) 14 refs.

  20. Maintenance and Drainage Guidance for the Scott Base Transition, Antarctica

    Science.gov (United States)

    2014-10-01

    albedo and quickens the melt. Several strategies reduce the amount of dirt tracked on- to the ice shelf: 1. Any vehicles using the ice shelf should...the Ice Transition segment of the SBT is to keep the snow albedo high (keep snow white). This reduces roadway and road-base disin- tegration (i.e...closest to the cliff was 38 ft (11.6 m) deep, and all but the furthest seaward hole encountered sediment (presumably the sea floor or the under- ice

  1. Tolerability and Healthcare Utilization in Maintenance Hemodialysis Patients Undergoing Treatment for Tuberculosis-Related Conditions.

    Science.gov (United States)

    Hamadah, Abdurrahman M; Beaulieu, Lynn M; Wilson, John W; Aksamit, Timothy R; Gregoire, James R; Williams, Amy W; Dillon, John J; Albright, Robert C; Onuigbo, Macaulay; Iyer, Venkateshwaran K; Hickson, LaTonya J

    2016-01-01

    The incidence of tuberculosis (TB) in end-stage renal disease is significantly higher than that in the general population. Among those with kidney dysfunction, anti-TB treatment is associated with increased side effects, but the effect on healthcare utilization is unknown. Methods/Aim: To assess patient-reported symptoms, adverse effects and describe changes in healthcare utilization patterns during treatment for TB, we conducted a case series (n = 12) of patients receiving maintenance hemodialysis (HD) from Mayo Clinic Dialysis Services and concurrent drug therapy for TB from January 2002 through May 2014. Healthcare utilization (hospitalizations and emergency department (ED) visits independent of hospital admission) was compared before and during treatment. Patients were treated for latent (n = 7) or active (n = 5) TB. The majority of patients with latent disease were treated with isoniazid (n = 5, 71%), while active-disease patients received a 4-drug regimen. Adverse effects were reported in 83% of patients. Compared to measurements prior to drug initiation, serum albumin and dialysis weights were similar at 3 months. Commonly reported anti-TB drug toxicities were described. More than half (58%) of the patients were hospitalized at least once. No ED or hospital admissions occurred in the period prior to drug therapy, but healthcare utilization increased during treatment in the latent disease group (hospitalization rate per person-month: pre 0 vs. post 1). Among HD patients, anti-TB therapy is associated with frequently reported symptoms and increased healthcare utilization. Among this subset, patients receiving treatment for latent disease may be those with greatest increase in healthcare use. Careful monitoring and early complication detection may help optimize medication adherence and minimize hospitalizations. © 2016 S. Karger AG, Basel.

  2. Home-based care, technology, and the maintenance of selves.

    Science.gov (United States)

    Parks, Jennifer A

    2015-06-01

    In this paper, I will argue that there is a deep connection between home-based care, technology, and the self. Providing the means for persons (especially older persons) to receive care at home is not merely a kindness that respects their preference to be at home: it is an important means of extending their selfhood and respecting the unique selves that they are. Home-based technologies like telemedicine and robotic care may certainly be useful tools in providing care for persons at home, but they also have important implications for sustaining selfhood in ways that are of value to individuals and those who care for them. I will argue, by appealing to Hilde Lindemann's notion of "holding" persons' identities in place, that technological interventions are not only useful tools for improving and sustaining health and good care at home, but that they may also help to extend our personal identities and relational capacities in ways that are practically and ethically good. Because of these important goods, I will claim that there is a prima facie moral duty to do this "holding" work and that it is best done by family members and loved ones who are well suited to the job because of their history and relationship with the individual that needs to be "held" in place.

  3. Remote condition-based monitoring of turbines

    International Nuclear Information System (INIS)

    2005-01-01

    specific point in time; Timewave: Amount of motion and symmetry of wave shape (i.e., a truncated wave can be an indication of a rub); Orbits: A cross-sectional view of shaft movement; DC Gap Voltage: A measurement of the distance (e.g., gap) between the shaft and the proximity probes. This value is useful in determining bearing wear of shaft centerline location. Daily monitoring of these metrics will not only warn of impending failure, but provide valuable information regarding the possible cause of the impending failure and an approximate indication of time to failure. In the event of a sudden problem and subsequent trip of a turbine, this data helps determine the root cause of the failure. This results in faster problem resolution and a quicker restart of the turbine. Additionally, daily monitoring of these metrics allows companies to watch a problematic turbine's health until the next scheduled outage. Azima's remote, condition-based monitoring system and diagnostics service is an effective way to collect and trend these metrics on a daily basis, as well as supply expert advice in the event of any anomalies. The Azima system aggregates the analog data from the proximity probes mounted on the turbine at a sensor hub. The sensor hub digitizes the analog data and then, either wirelessly or through a wired Ethernet connection, sends the data via the Internet to a hosted server. The hosted server maintains the software that trends the data (e.g., vibration, spectrum, timewave, DC gap voltage, and orbits) and provides automatic alerting. The data can be accessed anywhere, anytime through a standard Web browser. The advantages of daily, remote, condition-based monitoring include: Daily monitoring of vital turbine health metrics to detect impending problems before they become critical; Automatic alerting when a change in condition is detected; Anywhere, anytime access via a standard Web browser. This allows multiple groups at different locations to simultaneously review and

  4. Boundary Conditions for the Maintenance of Memory by PKM[zeta] in Neocortex

    Science.gov (United States)

    Shema, Reul; Hazvi, Shoshi; Sacktor, Todd C.; Dudai, Yadin

    2009-01-01

    We report here that ZIP, a selective inhibitor of the atypical protein kinase C isoform PKM[zeta], abolishes very long-term conditioned taste aversion (CTA) associations in the insular cortex of the behaving rat, at least 3 mo after encoding. The effect of ZIP is not replicated by a general serine/threonine protein kinase inhibitor that is…

  5. Technical requirements on knowledge base and instrumentation system for decision making in plant operation and maintenance

    International Nuclear Information System (INIS)

    Kitamura, Masaharu; Yoshikawa, Shinji; Hasegawa, Makoto

    1998-03-01

    A series of technical surveys and studies are described in this report to examine and identify technical requirements to be posed on knowledge base and instrumentation system as the fundamental in high reliability computational decision making in operation and maintenance of nuclear power plants. Monitoring and diagnosis are focused as the important tasks among the operation/maintenance-related tasks. A concrete monitoring and diagnosis system configuration has been proposed consisting of distributed symptom database and of on-demand measurement subsystem. An prototype of the proposed system configuration has been successfully verified. (author)

  6. On risk-based operation and maintenance of offshore wind turbine components

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2011-01-01

    Operation and maintenance are significant contributors to the cost of energy for offshore wind turbines. Optimal planning could rationally be based on Bayesian pre-posterior decision theory, and all costs through the lifetime of the structures should be included. This paper contains a study...... of a generic case where the costs are evaluated for a single wind turbine with a single component. Costs due to inspections, repairs, and lost production are included in the model. The costs are compared for two distinct maintenance strategies, namely with and without inclusion of periodic imperfect...

  7. An overview of the recent advances in delay-time-based maintenance modelling

    International Nuclear Information System (INIS)

    Wang, Wenbin

    2012-01-01

    Industrial plant maintenance is an area which has enormous potential to be improved. It is also an area attracted significant attention from mathematical modellers because of the random phenomenon of plant failures. This paper reviews the recent advances in delay-time-based maintenance modelling, which is one of the mathematical techniques for optimising inspection planning and related problems. The delay-time is a concept that divides a plant failure process into two stages: from new until the point of an identifiable defect, and then from this point to failure. The first stage is called the normal working stage and the second stage is called the failure delay-time stage. If the distributions of the two stages can be quantified, the relationship between the number of failures and the inspection interval can be readily established. This can then be used for optimizing the inspection interval and other related decision variables. In this review, we pay particular attention to new methodological developments and industrial applications of the delay-time-based models over the last few decades. The use of the delay-time concept and modeling techniques in other areas rather than in maintenance is also reviewed. Future research directions are also highlighted. - Highlights: ► Reviewed the recent advances in delay-time-based maintenance models and applications. ► Compared the delay-time-based models with other models. ► Focused on methodologies and applications. ► Pointed out future research directions.

  8. Automotive Maintenance Data Base for Model Years 1976-1979. Part II : Appendix E and F

    Science.gov (United States)

    1980-12-01

    An update of the existing data base was developed to include life cycle maintenance costs of representative vehicles for the model years 1976-1979. Repair costs as a function of time are also developed for a passenger car in each of the compact, subc...

  9. No functional role of attention-based rehearsal in maintenance of spatial working memory representations

    NARCIS (Netherlands)

    Belopolsky, A.V.; Theeuwes, J.

    2009-01-01

    The present study systematically examined the role of attention in maintenance of spatial representations in working memory as proposed by the attention-based rehearsal hypothesis [Awh, E., Jonides, J., & Reuter-Lorenz, P. A. (1998). Rehearsal in spatial working memory. Journal of Experimental

  10. Automotive Maintenance Data Base for Model Years 1976-1979. Part I

    Science.gov (United States)

    1980-12-01

    An update of the existing data base was developed to include life cycle maintenance costs of representative vehicles for the model years 1976-1979. Repair costs as a function of time are also developed for a passenger car in each of the compact, subc...

  11. An Enhanced Preventive Maintenance Optimization Model Based on a Three-Stage Failure Process

    Directory of Open Access Journals (Sweden)

    Ruifeng Yang

    2015-01-01

    Full Text Available Nuclear power plants are highly complex systems and the issues related to their safety are of primary importance. Probabilistic safety assessment is regarded as the most widespread methodology for studying the safety of nuclear power plants. As maintenance is one of the most important factors for affecting the reliability and safety, an enhanced preventive maintenance optimization model based on a three-stage failure process is proposed. Preventive maintenance is still a dominant maintenance policy due to its easy implementation. In order to correspond to the three-color scheme commonly used in practice, the lifetime of system before failure is divided into three stages, namely, normal, minor defective, and severe defective stages. When the minor defective stage is identified, two measures are considered for comparison: one is that halving the inspection interval only when the minor defective stage is identified at the first time; the other one is that if only identifying the minor defective stage, the subsequent inspection interval is halved. Maintenance is implemented immediately once the severe defective stage is identified. Minimizing the expected cost per unit time is our objective function to optimize the inspection interval. Finally, a numerical example is presented to illustrate the effectiveness of the proposed models.

  12. Managing wind turbine reliability and maintenance via performance-based contract

    DEFF Research Database (Denmark)

    Jin, Tongdan; Ding, Yi; Guo, Huairui

    2012-01-01

    between system cost, reliability and spare parts stocking. This analytical insight into the system performance allows the turbine manufacturer to optimize design, production, and after-sales services. The study aims to create a theoretical basis to facilitate the transition of the maintenance paradigm......Performance-based contracting (PBC) is reshaping the acquisition, operation, and maintenance of capital equipment. Under the PBC scheme, we propose a holistic approach for lowering the cost of wind turbine ownership while meeting the availability requirement. Our effects are focused on integrated...... firms who design and market wind turbines, and also provide maintenance and repair service. PBC differs from conventional service contracts in that the wind farmers compensate the service provider for the system performance, not the spare parts and repair labor. We explore the analytical relationship...

  13. Longitudinal Relationship between Plasma Reactive Oxygen Metabolites and Periodontal Condition in the Maintenance Phase of Periodontal Treatment

    Directory of Open Access Journals (Sweden)

    Tatsuya Machida

    2014-01-01

    Full Text Available Aim. The present cohort study describes the longitudinal relationship between plasma oxidative status and periodontitis progression during the maintenance phase of treatment. Materials and Methods. Forty-five patients (mean age 58.8 years were monitored from 2008 to 2013. Periodontal conditions, including probing pocket depth (PPD and clinical attachment level (CAL, were recorded. Measurements of plasma reactive oxygen metabolites (ROM and biologic antioxidant potential (BAP were performed to evaluate plasma oxidative status. The patients were assigned into 2 groups as low and high plasma ROM level using a cut-off value which was median of plasma ROM level at baseline. Results. In the subjects with low plasma ROM level at baseline, changes in mean CAL were positively correlated with changes in plasma ROM levels, bleeding on probing, and plaque control record, but not with PPD. In the subjects with high plasma ROM at baseline, changes in CAL were significantly associated with only PPD at baseline. On the other hands there were no significant associations between changes in CAL and those in plasma BAP levels. Conclusions. When plasma ROM level in periodontitis patients was low, increases in plasma ROM level were associated with those in CAL during the maintenance phase of treatment.

  14. Maintenance management for nuclear power plant 'Integrated valve maintenance'

    International Nuclear Information System (INIS)

    Gerner, P.; Zanner, G.

    2001-01-01

    The deregulation of Europe's power market does force many utilities, and especially nuclear power plant operators, to introduce extensive cost-cutting measures in order to be able to compete within this new environment. The optimization of plant outages provides considerable potential for raising plant availability but can also lower operating costs by reducing e.g. expenditure on maintenance. Siemens Nuclear Power GmbH, in cooperation with plant operators, is currently implementing new and improved service concepts which can have a major effect on the way in which maintenance will be performed in the future. Innovative service packages for maintenance in nuclear power plants are available which can be used to perform a time- and cost-effective maintenance. The concepts encompass optimization of the overall sequence from planning in advance to the individual measures including reduction of the scope of maintenance activities, identification of cost cutting potential and bundling of maintenance activities. The main features of these maintenance activities are illustrated here using the examples of outage planning and integrated valve maintenance. In nuclear power plants approx. 5000 valves are periodically preventively, condition-based or breakdown-based maintained. Because of this large number of valves to be maintained a high potential of improvements and cost reductions can be achieved by performing an optimized, cost-effective maintenance based on innovative methods and tools. Siemens Nuclear Power GmbH has developed and qualified such tools which allow to reduce service costs while maintaining high standards of safety and availability. By changing from preventive to predictive (condition-based) maintenance - the number of valves to be maintained may be reduced considerably. The predictive maintenance is based on the Siemens Nuclear Power GmbH diagnostic and evaluation method (ADAM). ADAM is used to monitor the operability of valves by analytical verification of

  15. Concept design of CFETR superconducting magnet system based on different maintenance ports

    International Nuclear Information System (INIS)

    Zheng, Jinxing; Liu, Xufeng; Song, Yuntao; Wan, Yuanxi; Li, Jiangang; Wu, Sontao; Wan, Baonian; Ye, Minyou; Wei, Jianghua; Xu, Weiwei; Liu, Sumei; Weng, Peide; Lu, Kun; Luo, Zhengping

    2013-01-01

    Highlights: • This article discussed the concept design of the magnet system of CFETR based on different maintenance port cases. • The major and minor radius of plasma is 5.7 m and 1.6 m, and the central magnetic field was designed as 4.5/5.0 T. • The different maintenance ports design have little impact on the design of TF and CS coils’ design, but have certain impact on the PF coils’ design. -- Abstract: CFETR which stands for “China Fusion Engineering Test Reactor” is a new tokamak device. Its magnet system includes the Toroidal Field (TF) winding, Center solenoid winding (CS) and Poloidal Field (PF) winding. The main goal of the project is to build a fusion engineering Tokamak reactor with its fusion power is 50–200 MW and should be self-sufficiency by blanket. In order to ensure the maintenance ports design and maintenance method, this article discussed the concept design of the magnet system based on different maintenance port cases. The paper detailed studied the magnet system of CFETR including the electromagnetic analysis and parameters for TF (CS)PF. Besides, the volt-seconds of ohmic field are presented as detailed as possible in this paper. In addition, the calculations and optimizations of equilibrium field which should guarantee the plasma discharge of single null shape is carried out. The design work reported here illustrates that the present maintenance ports will not have a great impact on the design of the magnet system. The concept design of the magnet system can meet the requirement of the physical target

  16. Integrated maintenance program (IMP)

    International Nuclear Information System (INIS)

    Zemdegs, R.T.; Chout, Q.B.

    1998-01-01

    Approaches to the maintenance of nuclear power plants have undergone significant change in the past several decades. The traditional breakdown approach has been displaced by preventive (calendar-based) maintenance and more recently, by condition-based maintenance (CBM). This is largely driven by the fact that traditional maintenance programs, derived primarily from equipment vendor recommendations, are generally unsuccessful in controlling maintenance costs or equipment failures. Many advances in the maintenance field have taken place since the maintenance plans for Ontario Hydro's nuclear plants were initially established. Ontario Hydro nuclear plant operating costs can be substantially reduced and Incapability Factor improved with the application of modern maintenance processes and tools. Pickering is designated as the lead station for IMP. Of immediate concern is the fact that Pickering Nuclear Division has been experiencing a significant backlog of Operating Preventive Maintenance Callups. This backlog, over 2000, is unacceptable to both station management and the nuclear regulator, the Atomic Energy Control Board. In addition there are over 500 callups in various stages of revision (in hyperspace) without an adequate control nor reporting system to manage their completion. There is also considerable confusion about the classification of l icensing c allups, e.g. callups which are mandatory as a result of legal requirements. Furthermore the ineffectiveness of the Preventive Maintenance (PM) has been the subject of peer audits and Atomic Energy Control Board (AECB) findings over the past several years. The current preventive maintenance ratio PM2 /(PM+CM3) at Pickering ND is less than 20%, due to the current high load of equipment breakdown. This past summer, an Independent Integrated Performance Assessment (IIPA) review at Ontario Hydro confirmed these concerns. Over the past several years, Ontario Hydro nuclear staff have evaluated several programs to improve

  17. Boundary conditions for the maintenance of memory by PKMzeta in neocortex.

    Science.gov (United States)

    Shema, Reut; Hazvi, Shoshi; Sacktor, Todd C; Dudai, Yadin

    2009-02-01

    We report here that ZIP, a selective inhibitor of the atypical protein kinase C isoform PKMzeta, abolishes very long-term conditioned taste aversion (CTA) associations in the insular cortex of the behaving rat, at least 3 mo after encoding. The effect of ZIP is not replicated by a general serine/threonine protein kinase inhibitor that is relatively ineffective toward PKMzeta, is independent of the intensity of training and the perceptual quality of the taste saccharin (conditioned stimulus, CS), and does not affect the ability of the insular cortex to re-encode the same specific CTA association again. The memory trace is, however, insensitive to ZIP during or immediately after training. This implies that the experience-dependent cellular plasticity mechanism targeted by ZIP is established following a brief time window after encoding, consistent with the standard period of cellular consolidation, but then, once established, does not consolidate further to gain immunity to the amnesic agent. Hence, we conclude that PKMzeta is not involved in short-term CTA memory, but is a critical component of the cortical machinery that stores long- and very long-term CTA memories.

  18. The role of the restructured Mobile Remote Service Base System (MBS) in support of Space Station maintenance and servicing

    Science.gov (United States)

    Darlington, T.; Krukewich, K.

    1992-08-01

    The critical parameters resulting from the restructuring of Space Station Freedom which necessitated the redesign of the Mobile Remote Service Base System (MBS) are described. These include optimization of robotic attachment locations for access to the Space Station truss-mounted orbital replacement units, transport of logistics carriers to the maintenance sites, minimization of EVA overhead associated with maintenance, self-maintenance of other mobile servicing system (MSS) elements on the MBS, and balancing of station EVA and extravehicular robotics in a complementary fashion to minimize maintenance overhead in general. Consideration is given to the configuration of the resulting MBS, which provides the program with maximum flexibility to utilize the assets of the MSS and optimizes end-to-end maintenance with regard to the use of station resources such as crew time and power. Maintenance and servicing scenarios which are instrumental to the reconfigured MBS as well as the results of improved maintenance capability are presented.

  19. Advanced Maintenance Simulation by Means of Hand-Based Haptic Interfaces

    Science.gov (United States)

    Nappi, Michele; Paolino, Luca; Ricciardi, Stefano; Sebillo, Monica; Vitiello, Giuliana

    Aerospace industry has been involved in virtual simulation for design and testing since the birth of virtual reality. Today this industry is showing a growing interest in the development of haptic-based maintenance training applications, which represent the most advanced way to simulate maintenance and repair tasks within a virtual environment by means of a visual-haptic approach. The goal is to allow the trainee to experiment the service procedures not only as a workflow reproduced at a visual level but also in terms of the kinaesthetic feedback involved with the manipulation of tools and components. This study, conducted in collaboration with aerospace industry specialists, is aimed to the development of an immersive virtual capable of immerging the trainees into a virtual environment where mechanics and technicians can perform maintenance simulation or training tasks by directly manipulating 3D virtual models of aircraft parts while perceiving force feedback through the haptic interface. The proposed system is based on ViRstperson, a virtual reality engine under development at the Italian Center for Aerospace Research (CIRA) to support engineering and technical activities such as design-time maintenance procedure validation, and maintenance training. This engine has been extended to support haptic-based interaction, enabling a more complete level of interaction, also in terms of impedance control, and thus fostering the development of haptic knowledge in the user. The user’s “sense of touch” within the immersive virtual environment is simulated through an Immersion CyberForce® hand-based force-feedback device. Preliminary testing of the proposed system seems encouraging.

  20. MOVES: A knowledge-based system for maintenance planning for motor-operated valves

    International Nuclear Information System (INIS)

    Winter, M.

    1987-01-01

    Over the past several years, knowledge-based expert systems have emerged as an important part of the general research area known as artificial intelligence. This paper describes a cooperative effort between faculty members at Iowa State University and engineers at the Duane Arnold Energy Center [a 545-MW(electric) boiling water reactor operated by Iowa Electric Light and Power Company] to explore the development of an advisory system for valve maintenance planning. This knowledge-based program, known as Motor-Operated Valves Expert System (MOVES), has a data base that currently includes safety-related motor-operated valves (∼117 valves). Valve maintenance was selected as the subject for the expert system because of the importance of valves in nuclear plant and their impact of plant availability. MOVES is being developed using the microcomputer-(IBM compatible) based expert system tool INSIGHT2+. The authors have found that the project benefits both the university and the utility

  1. Methodology for reliability based condition assessment

    International Nuclear Information System (INIS)

    Mori, Y.; Ellingwood, B.

    1993-08-01

    Structures in nuclear power plants may be exposed to aggressive environmental effects that cause their strength to decrease over an extended period of service. A major concern in evaluating the continued service for such structures is to ensure that in their current condition they are able to withstand future extreme load events during the intended service life with a level of reliability sufficient for public safety. This report describes a methodology to facilitate quantitative assessments of current and future structural reliability and performance of structures in nuclear power plants. This methodology takes into account the nature of past and future loads, and randomness in strength and in degradation resulting from environmental factors. An adaptive Monte Carlo simulation procedure is used to evaluate time-dependent system reliability. The time-dependent reliability is sensitive to the time-varying load characteristics and to the choice of initial strength and strength degradation models but not to correlation in component strengths within a system. Inspection/maintenance strategies are identified that minimize the expected future costs of keeping the failure probability of a structure at or below an established target failure probability during its anticipated service period

  2. EFFECTIVENESS OF DIFFERENT TRAINING PROGRAMS FOR PHYSICAL PERFORMANCE MAINTENANCE IN THE CONDITION OF LOW MOTOR ACTIVITY.

    Science.gov (United States)

    Fomina, E V; Uskov, K V

    Investigations made by the World Health Organization showed that lack. of physical activity and sedentary lifestyle are among ten major causes for death and disability. Typially, studies of the negative effects of reduced physical activity and their prevention face difficulties of providing standard conditions. These issues were obviated successfully in experiment MARS-500 on simulation of a space exploration mission. Human subjects were 6 men from Russia, France, Italy and China who spent 520 days in isolation. To prevent the negative effects of low physical activity, the volunteers performed resistive and cyclic exercises in different periods of isolation. The study was designed with two pauses in the training program. Physical performance was evaluated with an incremental loading test, maximal voluntary effort test (Russian-Austrian MDS resistive exercise system), and PWC-170 (bicycle ergometer). Level of physical performance of the subjects in this experiment never degraded to below baseline values. The proposed training system comprising different kinds of exercise ensured stability or improvement of subjects' physical performance as compared with baseline level.

  3. Optimal Medical Equipment Maintenance Service Proposal Decision Support System combining Activity Based Costing (ABC) and the Analytic Hierarchy Process (AHP).

    Science.gov (United States)

    da Rocha, Leticia; Sloane, Elliot; M Bassani, Jose

    2005-01-01

    This study describes a framework to support the choice of the maintenance service (in-house or third party contract) for each category of medical equipment based on: a) the real medical equipment maintenance management system currently used by the biomedical engineering group of the public health system of the Universidade Estadual de Campinas located in Brazil to control the medical equipment maintenance service, b) the Activity Based Costing (ABC) method, and c) the Analytic Hierarchy Process (AHP) method. Results show the cost and performance related to each type of maintenance service. Decision-makers can use these results to evaluate possible strategies for the categories of equipment.

  4. The improvement of maintenance service for traction networks equipment on the base of process approach

    Directory of Open Access Journals (Sweden)

    D. V. Mironov

    2014-12-01

    Full Text Available Purpose. The new methods development for improving the maintenance service for equipment of traction networks in order to increase its efficiency and quality. Methodology. In world practice of solving problems related to the quality of products and services is usually achieved by introducing quality management system in to the enterprises. The provisions of quality management system were used for solving the problem. The technologies of process engineering were used for describing the main stages of maintenance service. Findings. The development of high-speed movement and growth of its intensity, the use of electric rolling stock of a new generation require the introduction of new methods diagnostics of equipment technical state and improvement of the existing maintenance system and repair of power supply. Developing a model of business-processes, their optimization with using techniques of process engineering and system management is needed for the transition to the management system based on the process approach. From the standpoint of the process approach and in accordance with the requirements of the quality management system (ISO 9001-2009, the operation of the E (Department of electrification and power supply infrastructure sector is represented as a scheme of business-processes in which the guaranteed supply with electricity of railway and third-party consumers is defined as the main business-process of management. Each of the sub-process of power supply for consumers is described in details. The use methods and main stages of process approach for sample management system reorganization were investigated. The methodology and the application method of PDCA (Plan-Do-Check-Act closed loop to the equipment maintenance system were described. The monitoring process of traction networks maintenance using the process approach was divided into components after investigations. The technical documentation of maintenance service was investigated in

  5. Upgrade of maintenance technologies of Nuclear Power Plants

    International Nuclear Information System (INIS)

    Kamada, Kazuaki

    2005-01-01

    In order to enhance long-term safe and stable operation of Ikata Nuclear Power Plants (NPPs) in more efficient way, maintenance technology upgrade project was started aiming at establishment of simplified and efficient self-maintenance system with affiliated companies. Maintenance technique and supervisor qualification system was introduced after improvement and reinforcement of personnel education and training. Reflecting investigation of maintenance activities of US NPPs and productivity improvement in other industries, preventive maintenance optimization project had been performed such as introduction of key performance indicator (KPI), new system incorporating reliability-centered maintenance (RCM) and condition-based maintenance (CBM), and on-line monitoring and maintenance (OLM) based on risk assessment. Enterprise asset management (EAM) to establish information data base and total productive maintenance (TPM) action for every personnel to participate in self-maintenance was also introduced. (T. Tanaka)

  6. Analyzing maintenance strategies by agent-based simulations: A feasibility study

    International Nuclear Information System (INIS)

    Kaegi, M.; Mock, R.; Kroeger, W.

    2009-01-01

    Thoroughly planned and implemented maintenance strategies save time and cost. However, the integration of maintenance work into reliability analysis is difficult as common modeling techniques are often not applicable due to state explosion which calls for restrictive model assumptions and oversimplification. From authors' point of view, agent-based modeling (ABM) of technical and organizational systems is a promising approach to overcome such problems. But since ABM is not well established in reliability analysis its feasibility in this area still has to be demonstrated. For this purpose ABM is compared with Markov chains, namely by analyzing the reliability of a maintained n-unit system with dependent repair events, applying both modeling approaches. Although ABM and Markov chains lead to the same numerical results, the former points out the potentiality of an improved system state handling. This is demonstrated by extending the ABM with operators as additional 'agents' featuring their location (x;y) availability (0;1) and different maintenance strategies. This extension highlights the capability of ABM to analyze complex emergent system behavior and allows a systematic refinement and optimization of the maintenance strategies.

  7. A reliability-based preventive maintenance methodology for the projection spot welding machine

    Directory of Open Access Journals (Sweden)

    Fayzimatov Ulugbek

    2018-06-01

    Full Text Available An effective operations of a projection spot welding (PSW machine is closely related to the effec-tiveness of the maintenance. Timely maintenance can prevent failures and improve reliability and maintainability of the machine. Therefore, establishing the maintenance frequency for the welding machine is one of the most important tasks for plant engineers. In this regard, reliability analysis of the welding machine can be used to establish preventive maintenance intervals (PMI and to identify the critical parts of the system. In this reliability and maintainability study, analysis of the PSW machine was carried out. The failure and repair data for analysis were obtained from automobile manufacturing company located in Uzbekistan. The machine was divided into three main sub-systems: electrical, pneumatic and hydraulic. Different distributions functions for all sub-systems was tested and their parameters tabulated. Based on estimated parameters of the analyzed distribu-tions, PMI for the PSW machines sub-systems at different reliability levels was calculated. Finally, preventive measures for enhancing the reliability of the PSW machine sub-systems are suggested.

  8. VICKEY: Mining Conditional Keys on Knowledge Bases

    DEFF Research Database (Denmark)

    Symeonidou, Danai; Prado, Luis Antonio Galarraga Del; Pernelle, Nathalie

    2017-01-01

    A conditional key is a key constraint that is valid in only a part of the data. In this paper, we show how such keys can be mined automatically on large knowledge bases (KBs). For this, we combine techniques from key mining with techniques from rule mining. We show that our method can scale to KBs...

  9. A method for accounting for maintenance costs in flux balance analysis improves the prediction of plant cell metabolic phenotypes under stress conditions.

    Science.gov (United States)

    Cheung, C Y Maurice; Williams, Thomas C R; Poolman, Mark G; Fell, David A; Ratcliffe, R George; Sweetlove, Lee J

    2013-09-01

    Flux balance models of metabolism generally utilize synthesis of biomass as the main determinant of intracellular fluxes. However, the biomass constraint alone is not sufficient to predict realistic fluxes in central heterotrophic metabolism of plant cells because of the major demand on the energy budget due to transport costs and cell maintenance. This major limitation can be addressed by incorporating transport steps into the metabolic model and by implementing a procedure that uses Pareto optimality analysis to explore the trade-off between ATP and NADPH production for maintenance. This leads to a method for predicting cell maintenance costs on the basis of the measured flux ratio between the oxidative steps of the oxidative pentose phosphate pathway and glycolysis. We show that accounting for transport and maintenance costs substantially improves the accuracy of fluxes predicted from a flux balance model of heterotrophic Arabidopsis cells in culture, irrespective of the objective function used in the analysis. Moreover, when the new method was applied to cells under control, elevated temperature and hyper-osmotic conditions, only elevated temperature led to a substantial increase in cell maintenance costs. It is concluded that the hyper-osmotic conditions tested did not impose a metabolic stress, in as much as the metabolic network is not forced to devote more resources to cell maintenance. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  10. Condition-based inspection/replacement policies for non-monotone deteriorating systems with environmental covariates

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xuejing [Universite de Technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279, 12 rue Marie Curie, 10010 Troyes (France); School of mathematics and statistics, Lanzhou University, Lanzhou 730000 (China); Fouladirad, Mitra, E-mail: mitra.fouladirad@utt.f [Universite de Technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279, 12 rue Marie Curie, 10010 Troyes (France); Berenguer, Christophe [Universite de Technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279, 12 rue Marie Curie, 10010 Troyes (France); Bordes, Laurent [Universite de Pau et des Pays de l' Adour, LMA UMR CNRS 5142, 64013 PAU Cedex (France)

    2010-08-15

    The aim of this paper is to discuss the problem of modelling and optimising condition-based maintenance policies for a deteriorating system in presence of covariates. The deterioration is modelled by a non-monotone stochastic process. The covariates process is assumed to be a time-homogenous Markov chain with finite state space. A model similar to the proportional hazards model is used to show the influence of covariates on the deterioration. In the framework of the system under consideration, an appropriate inspection/replacement policy which minimises the expected average maintenance cost is derived. The average cost under different conditions of covariates and different maintenance policies is analysed through simulation experiments to compare the policies performances.

  11. Condition-based inspection/replacement policies for non-monotone deteriorating systems with environmental covariates

    International Nuclear Information System (INIS)

    Zhao Xuejing; Fouladirad, Mitra; Berenguer, Christophe; Bordes, Laurent

    2010-01-01

    The aim of this paper is to discuss the problem of modelling and optimising condition-based maintenance policies for a deteriorating system in presence of covariates. The deterioration is modelled by a non-monotone stochastic process. The covariates process is assumed to be a time-homogenous Markov chain with finite state space. A model similar to the proportional hazards model is used to show the influence of covariates on the deterioration. In the framework of the system under consideration, an appropriate inspection/replacement policy which minimises the expected average maintenance cost is derived. The average cost under different conditions of covariates and different maintenance policies is analysed through simulation experiments to compare the policies performances.

  12. VICKEY: Mining Conditional Keys on Knowledge Bases

    OpenAIRE

    Symeonidou , Danai; Galárraga , Luis; Pernelle , Nathalie; Saïs , Fatiha; Suchanek , Fabian

    2017-01-01

    International audience; A conditional key is a key constraint that is valid in only a part of the data. In this paper, we show how such keys can be mined automatically on large knowledge bases (KBs). For this, we combine techniques from key mining with techniques from rule mining. We show that our method can scale to KBs of millions of facts. We also show that the conditional keys we mine can improve the quality of entity linking by up to 47 percentage points.

  13. Establishment of effective maintenance method based on the superior inspection technique for the deteriorating hot laboratory exhaust stack

    International Nuclear Information System (INIS)

    Mizukoshi, Yasutaka; Yasu, Tetsunori

    2012-06-01

    The Materials Monitoring Facility is equipped with an exhaust stack to emit air from a controlled area (the hot laboratory) into the atmosphere. Cracks and exfoliation have been observed for the surface of the exhaust stack, which is made of reinforced concrete and was constructed on the seacoast about 25 years ago, so exposed to a salt-corrosive condition. In order to get details of the present condition of the exhaust stack, an inspection was carried out using an electromagnetic wave radar method and chloride content method. Cracks and exfoliation were observed for the whole stack surface, especially for high positions. Moreover, salt damage was observed for the outer surface of the exhaust stack, and it was estimated that the infiltration of the chloride content was about 17 mm. Based on this detailed inspection of the exhaust stack, maintenance and repair work were carried out. (author)

  14. Reliability-Based Planning of Inspection, Operation and Maintenance for Offshore Oil & Gas Structures and Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2011-01-01

    Reliability-based cost-optimal planning of inspection, maintenance and operation has many applications. In this paper applications for planning of inspections for oil & gas jacket structures and of operation and maintenance of offshore wind turbines are described and illustrated by examples....

  15. An All-Recombinant Protein-Based Culture System Specifically Identifies Hematopoietic Stem Cell Maintenance Factors

    Directory of Open Access Journals (Sweden)

    Aki Ieyasu

    2017-03-01

    Full Text Available Hematopoietic stem cells (HSCs are considered one of the most promising therapeutic targets for the treatment of various blood disorders. However, due to difficulties in establishing stable maintenance and expansion of HSCs in vitro, their insufficient supply is a major constraint to transplantation studies. To solve these problems we have developed a fully defined, all-recombinant protein-based culture system. Through this system, we have identified hemopexin (HPX and interleukin-1α as responsible for HSC maintenance in vitro. Subsequent molecular analysis revealed that HPX reduces intracellular reactive oxygen species levels within cultured HSCs. Furthermore, bone marrow immunostaining and 3D immunohistochemistry revealed that HPX is expressed in non-myelinating Schwann cells, known HSC niche constituents. These results highlight the utility of this fully defined all-recombinant protein-based culture system for reproducible in vitro HSC culture and its potential to contribute to the identification of factors responsible for in vitro maintenance, expansion, and differentiation of stem cell populations.

  16. On risk-based operation and maintenance of offshore wind turbine components

    International Nuclear Information System (INIS)

    Jessen Nielsen, Jannie; Dalsgaard Sorensen, John

    2011-01-01

    Operation and maintenance are significant contributors to the cost of energy for offshore wind turbines. Optimal planning could rationally be based on Bayesian pre-posterior decision theory, and all costs through the lifetime of the structures should be included. This paper contains a study of a generic case where the costs are evaluated for a single wind turbine with a single component. Costs due to inspections, repairs, and lost production are included in the model. The costs are compared for two distinct maintenance strategies, namely with and without inclusion of periodic imperfect inspections. Finally the influence of different important parameters, e.g. failure rate, reliability of inspections, inspection interval, and decision rule for repairs, is evaluated.

  17. Statistical models based on conditional probability distributions

    International Nuclear Information System (INIS)

    Narayanan, R.S.

    1991-10-01

    We present a formulation of statistical mechanics models based on conditional probability distribution rather than a Hamiltonian. We show that it is possible to realize critical phenomena through this procedure. Closely linked with this formulation is a Monte Carlo algorithm, in which a configuration generated is guaranteed to be statistically independent from any other configuration for all values of the parameters, in particular near the critical point. (orig.)

  18. VERSHINA – A POLISH VILLAGE IN SIBERIA. FACTORS INFLUENCING LANGUAGE MAINTENANCE UNDER CHANGING SOCIAL, CULTURAL, ECONOMIC AND POLITICAL CONDITIONS

    Directory of Open Access Journals (Sweden)

    Michał Głuszkowski

    2011-01-01

    Full Text Available The article discusses factors influencing language maintenance under changing social, cultural, economic and political conditions of Polish minority in Siberia. The village of Vershina was founded in 1910 by Polish voluntary settlers from Little Poland.During its first three decades Vershina preserved Polish language,traditions, farming methods and machines and also the Roman Catholic religion. The changes came to a village in taiga in the1930s. Vershina lost its ethnocultural homogeneity because of Russian and Buryat workers in the local kolkhoz. Nowadays the inhabitants of Vershina regained their minority rights: religious, educational and cultural. However, during the years of sovietization and ateization, their culture and customs became much more similar to other Siberian villages. Polish language in Vershina is under strong influence of Russian, which is the language of education,administration, and surrounding villages. Children from Polish-Russian families become monolingual and use Polish very rare, only asa school subject and in contacts with grandparents. The process of abandoning mother tongue in Vershina is growing rapidly. However,there are some factors which may hinder the actual changes:the activity of local Polish organisations and Roman Catholic parish as well as folk group “Jazhumbek”.

  19. An overview of a knowledge based system for preventive maintenance support of nuclear power plants

    International Nuclear Information System (INIS)

    Terano, Takao; Nishiyama, Takuya; Yokoo, Takeshi

    1984-01-01

    In recent years, much interest has been paid to knowledge engineering techniques for new vehicles of advanced information processing. As a practical application in electric power industry, this report discusses a knowledge based system for supporting preventive maintenance of nuclear power plants. To support preventive maintenance tasks, the system must have facilities to reason failures and accidents of the plants, to evaluate their significance, to predict any possible troubles, and to indentify appropriate preventive countermeasures for them. This report describes the overview of the prototype system from a viewpoint of knowledge engineering. The results of the study are as follows: (1) The knowledge base of the prototype system consists of a data-base on plants and a rule-base derived from experts' knowledge. Using the information in the knowledge base, the system diagnoses the plant without real-time interaction with operational plants. (2) Expert's knowledge in the rule-base is represented in the non-procedural declarative forms. These rules are organized in some hierarchical structure so as to be used efficiently and used in conjunction with the corresponding set of plant information in the data-base. (3) The prototype system is incrementally developed with the rapid prototyping techniques, that is, the processes of design, implementation and evaluation are repeated several times. (author)

  20. Using systematic aging assessments to improve effectiveness of plant maintenance programs

    International Nuclear Information System (INIS)

    Watson, P.; Yang, J.X.; Dam, R.F.; Nickerson, J.H.

    2003-01-01

    Nuclear plant equipment aging assessment studies provided by AECL include life assessments, condition assessments or systematic assessments of maintenance. AECL has developed several tools to apply the results of aging assessment studies to improve the effectiveness of actual plant maintenance programs. The Systematic Assessment of Maintenance and the SYSTMS tool generate maintenance tasks for a system. The System Maintenance Datastore tool assesses the maintenance resources on a system basis, and can thus quantify the savings realized by optimizing the maintenance program. Long term trends in condition-based maintenance due to component aging can be predicted, and resource savings due to optimum timing of component replacement or general plant refurbishment can be quantified. The System based Adaptive Maintenance Process ensures the maintenance program is continually updated to reflect the latest plant equipment condition and maintenance strategy information. (author)

  1. A framework for the design of a voice-activated, intelligent, and hypermedia-based aircraft maintenance manual

    Science.gov (United States)

    Patankar, Manoj Shashikant

    Federal Aviation Regulations require Aviation Maintenance Technicians (AMTs) to refer to approved maintenance manuals when performing maintenance on airworthy aircraft. Because these manuals are paper-based, larger the size of the aircraft, more cumbersome are the manuals. Federal Aviation Administration (FAA) recognized the difficulties associated with the use of large manuals and conducted studies on the use of electronic media as an alternative to the traditional paper format. However, these techniques do not employ any artificial intelligence technologies and the user interface is limited to either a keyboard or a stylus pen. The primary emphasis of this research was to design a generic framework that would allow future development of voice-activated, intelligent, and hypermedia-based aircraft maintenance manuals. A prototype (VIHAMS-Voice-activated, Intelligent, and Hypermedia-based Aircraft Maintenance System) was developed, as a secondary emphasis, using the design and development techniques that evolved from this research. An evolutionary software design approach was used to design the proposed framework and the structured rapid prototyping technique was used to produce the VIHAMS prototype. VoiceAssist by Creative Labs was used to provide the voice interface so that the users (AMTs) could keep their hands free to work on the aircraft while maintaining complete control over the computer through discrete voice commands. KnowledgePro for Windows sp{TM}, an expert system shell, provided "intelligence" to the prototype. As a result of this intelligence, the system provided expert guidance to the user. The core information contained in conventional manuals was available in a hypermedia format. The prototype's operating hardware included a notebook computer with a fully functional audio system. An external microphone and the built-in speaker served as the input and output devices (along with the color monitor), respectively. Federal Aviation Administration

  2. Instrumentation maintenance

    International Nuclear Information System (INIS)

    Mack, D.A.

    1976-09-01

    It is essential to any research activity that accurate and efficient measurements be made for the experimental parameters under consideration for each individual experiment or test. Satisfactory measurements in turn depend upon having the necessary instruments and the capability of ensuring that they are performing within their intended specifications. This latter requirement can only be achieved by providing an adequate maintenance facility, staffed with personnel competent to understand the problems associated with instrument adjustment and repair. The Instrument Repair Shop at the Lawrence Berkeley Laboratory is designed to achieve this end. The organization, staffing and operation of this system is discussed. Maintenance policy should be based on studies of (1) preventive vs. catastrophic maintenance, (2) records indicating when equipment should be replaced rather than repaired and (3) priorities established to indicate the order in which equipment should be repaired. Upon establishing a workable maintenance policy, the staff should be instructed so that they may provide appropriate scheduled preventive maintenance, calibration and corrective procedures, and emergency repairs. The education, training and experience of the maintenance staff is discussed along with the organization for an efficient operation. The layout of the various repair shops is described in the light of laboratory space and financial constraints

  3. Bridge Condition Assessment based on Vibration Responses of Passenger Vehicle

    International Nuclear Information System (INIS)

    Miyamoto, Ayaho; Yabe, Akito

    2011-01-01

    In this paper, we propose a new method of assessing the condition of existing short- and medium-span reinforced/prestressed concrete bridges based on vibration monitoring data obtained from a public bus. This paper not only describes details of a prototype monitoring system that uses information technology and sensors capable of providing more accurate knowledge of bridge performance than conventional ways but also shows a few specific examples of bridge condition assessment based on vehicle vibrations measured by using an in-service public bus equipped with vibration measurement instrumentation. This paper also describes a sensitivity analysis of deteriorating bridges based on simulation of the acceleration response of buses conducted by the 'substructure method' employing a finite element model to verify the above bridge performance results. The main conclusions obtained in this study can be summarized as follows: (1) Because the vibration responses of passenger vehicles, such as buses, have a good linear relationship with the vibration responses of the target bridges, the proposed system can be used as a practical monitoring system for bridge condition assessment. (2) The results of sensitivity analysis performed by the substructure method show that bus vibration responses are useful for evaluating target bridge performance. (3) The proposed method was applied to a network of real bridges in a local area to evaluate its effectiveness. The results indicate that the proposed method can be used to prioritize the repair/strengthening works of existing bridges based on various vibration information in order to help bridge administrators establish rational maintenance strategies.

  4. Assessment of skeletal muscle fatigue of road maintenance workers based on heart rate monitoring and myotonometry

    Directory of Open Access Journals (Sweden)

    Kalkis Henrijs

    2006-07-01

    Full Text Available Abstract Objective This research work is dedicated to occupational health problems caused by ergonomic risks. The research object was road building industry, where workers have to work very intensively, have long work hours, are working in forced/constrained work postures and overstrain during the work specific parts of their bodies. The aim of this study was to evaluate the work heaviness degree and to estimate the muscle fatigue of workers after one week work cycle. The study group consisted of 10 road construction and maintenance workers and 10 pavers aged between 20 and 60 years. Methods Physical load were analyzed by measuring heart rate (HR, work postures (OWAS and perceived exertion (RPE. Assessments of the muscles strain and functional state (tone were carried out using myotonometric (MYO measurements. The reliability of the statistical processing of heart rate monitoring and myotonometry data was determined using correlating analysis. Results This study showed that that road construction and repairing works should be considered as a hard work according to average metabolic energy consumption 8.1 ± 1.5 kcal/min; paving, in its turn, was a moderately hard work according to 7.2 ± 1.1 kcal/min. Several muscle tone levels were identified allowing subdivision of workers into three conditional categories basing on muscle tone and fatigue: I – absolute muscle relaxation and ability to relax; II – a state of equilibrium, when muscles are able to adapt to the work load and are partly able to relax; and III – muscle fatigue and increased tone. It was also found out that the increase of muscle tone and fatigue mainly depend on workers physical preparedness and length of service, and less – on their age. Conclusion We have concluded that a complex ergonomic analysis consisting of heart rate monitoring, assessment of compulsive working postures and myotonometry is appropriate to assess the work heaviness degree and can provide prognosis of

  5. Maintenance strategy based on reliability functions for an oil centrifugal pump

    Directory of Open Access Journals (Sweden)

    Denis Carlos Mengue

    2013-06-01

    Full Text Available The purpose of this article was to define the most appropriate maintenance strategy for a centrifugal pump (preventive, predictive, corrective or emergency, based on reliability calculation. The research method was the quantitative modeling, applied in a petroleum plant. The study may contribute to the development of a strategic model for the management of the industrial plant maintenance. In the company's information system, records of eleven years have been gathered on times between failures and times for repair of the equipment. These times were modeled by probability distributions. From the results obtained were calculated Reliability and Maintainability functions R(t and M(t. By combining their expected values (MTBF and MTTR, Av availability was calculated. The figures for MTBF, MTTR and Av were respectively 3,936 hours, 133 hours and 96.73%. The most likely shape factor of the Weibull distribution which modeled the time between failures was 0.69. So, it was possible to affirm that the pump is in the infant mortality phase. The theoretical framework of RCM indicated corrective  maintenance as the strategy for the item. This strategy aims to eliminate the defects of equipment design, reinforce items that usually break and remove the causes of the failures.

  6. Probability-based assessment and maintenance of welded joints damaged by fatigue

    International Nuclear Information System (INIS)

    Cremona, C.; Lukic, M.

    1998-01-01

    This paper presents a probabilistic reliability assessment procedure for steel components damaged by fatigue. The study combines the structural reliability theory with a maintenance strategy. The fatigue assessment model is based on a modelisation of the fatigue phenomenon issued from the principles of fracture mechanics theory. The safety margin includes the crack growth propagation and allows to treat fatigue damage in a general manner. Damaging cycles and non damaging cycles are distinguished. The sensitivity study of the different parameters shows that some variables can be taken as deterministic. Applications are made on a welded joint 'stiffener/bottom-plate' of a typical steel bridge. The model is then used for taking into account inspection results. Non destructive inspection (NDI) techniques are also used for updating failure probabilities. The results show their ability to be inserted in a maintenance strategy for optimizing the next inspection time. This has led to define cost functions related to the total maintenance cost; this cost is then minimized for determining the optimal next inspection time. An example of welded joint cracked by fatigue highlights the different concepts. The approach presented in the paper is not only restrained to fatigue problems, but can be applied to a wide variety of degrading phenomena. (orig.)

  7. Partial maintenance of auditory-based cognitive training benefits in older adults

    Science.gov (United States)

    Anderson, Samira; White-Schwoch, Travis; Choi, Hee Jae; Kraus, Nina

    2014-01-01

    The potential for short-term training to improve cognitive and sensory function in older adults has captured the public’s interest. Initial results have been promising. For example, eight weeks of auditory-based cognitive training decreases peak latencies and peak variability in neural responses to speech presented in a background of noise and instills gains in speed of processing, speech-in-noise recognition, and short-term memory in older adults. But while previous studies have demonstrated short-term plasticity in older adults, we must consider the long-term maintenance of training gains. To evaluate training maintenance, we invited participants from an earlier training study to return for follow-up testing six months after the completion of training. We found that improvements in response peak timing to speech in noise and speed of processing were maintained, but the participants did not maintain speech-in-noise recognition or memory gains. Future studies should consider factors that are important for training maintenance, including the nature of the training, compliance with the training schedule, and the need for booster sessions after the completion of primary training. PMID:25111032

  8. Quaternion Based Thermal Condition Monitoring System

    Science.gov (United States)

    Wong, Wai Kit; Loo, Chu Kiong; Lim, Way Soong; Tan, Poi Ngee

    In this paper, we will propose a new and effective machine condition monitoring system using log-polar mapper, quaternion based thermal image correlator and max-product fuzzy neural network classifier. Two classification characteristics namely: peak to sidelobe ratio (PSR) and real to complex ratio of the discrete quaternion correlation output (p-value) are applied in the proposed machine condition monitoring system. Large PSR and p-value observe in a good match among correlation of the input thermal image with a particular reference image, while small PSR and p-value observe in a bad/not match among correlation of the input thermal image with a particular reference image. In simulation, we also discover that log-polar mapping actually help solving rotation and scaling invariant problems in quaternion based thermal image correlation. Beside that, log-polar mapping can have a two fold of data compression capability. Log-polar mapping can help smoother up the output correlation plane too, hence makes a better measurement way for PSR and p-values. Simulation results also show that the proposed system is an efficient machine condition monitoring system with accuracy more than 98%.

  9. The Maintenance of Heating, Ventilating and Air-Conditioning Systems and Indoor Air Quality in Schools: A Guide for School Facility Managers. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.

    To help maintain good indoor air quality (IAQ) in schools, guidance for the development and implementation of an effective program for maintenance and operation of heating, ventilating, and air-conditioning (HVAC) systems are discussed. Frequently, a building's occupants will complain about IAQ when the temperature or humidity are at uncomfortable…

  10. Evaluation of environmental and economic effectiveness of the Cross Compliance 4.3 Standards "Maintenance of olive groves and vineyards in good vegetative conditions"

    Directory of Open Access Journals (Sweden)

    Luigi Sansone

    2015-11-01

    Full Text Available This paper reports the first observations made in three farms of the Council for Agricultural Research and Economics (CREA relating to the environmental monitoring of the standard 4.3 maintenance of olive groves and vineyards in good vegetative conditions and analysis of differential of competitiveness  for both crops.

  11. A Wavelet Bicoherence-Based Quadratic Nonlinearity Feature for Translational Axis Condition Monitoring

    Directory of Open Access Journals (Sweden)

    Yong Li

    2014-01-01

    Full Text Available The translational axis is one of the most important subsystems in modern machine tools, as its degradation may result in the loss of the product qualification and lower the control precision. Condition-based maintenance (CBM has been considered as one of the advanced maintenance schemes to achieve effective, reliable and cost-effective operation of machine systems, however, current vibration-based maintenance schemes cannot be employed directly in the translational axis system, due to its complex structure and the inefficiency of commonly used condition monitoring features. In this paper, a wavelet bicoherence-based quadratic nonlinearity feature is proposed for translational axis condition monitoring by using the torque signature of the drive servomotor. Firstly, the quadratic nonlinearity of the servomotor torque signature is discussed, and then, a biphase randomization wavelet bicoherence is introduced for its quadratic nonlinear detection. On this basis, a quadratic nonlinearity feature is proposed for condition monitoring of the translational axis. The properties of the proposed quadratic nonlinearity feature are investigated by simulations. Subsequently, this feature is applied to the real-world servomotor torque data collected from the X-axis on a high precision vertical machining centre. All the results show that the performance of the proposed feature is much better than that of original condition monitoring features.

  12. Machinery prognostics and prognosis oriented maintenance management

    CERN Document Server

    Yan, Jihong

    2014-01-01

    This book gives a complete presentatin of the basic essentials of machinery prognostics and prognosis oriented maintenance management, and takes a look at the cutting-edge discipline of intelligent failure prognosis technologies for condition-based maintenance.  Latest research results and application methods are introduced for signal processing, reliability moelling, deterioration evaluation, residual life prediction and maintenance-optimization as well as applications of these methods.

  13. Risk-Based Operation and Maintenance of Offshore Wind Turbines using Bayesian Networks

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2011-01-01

    the lifetime. Two different approaches are used; one uses a threshold value of the failure probability, and one uses a Limited Memory Influence Diagram. Both methods are tested for an application example using MonteCarlo sampling, and they are both found to be efficient and equally good.......For offshore wind farms, the costs due to operation and maintenance are large, and more optimal planning has the potential of reducing these costs. This paper presents how Bayesian networks can be used for risk-based inspection planning, where the inspection plans are updated each year through...

  14. Reliability-based optimization of maintenance scheduling of mechanical components under fatigue

    Science.gov (United States)

    Beaurepaire, P.; Valdebenito, M.A.; Schuëller, G.I.; Jensen, H.A.

    2012-01-01

    This study presents the optimization of the maintenance scheduling of mechanical components under fatigue loading. The cracks of damaged structures may be detected during non-destructive inspection and subsequently repaired. Fatigue crack initiation and growth show inherent variability, and as well the outcome of inspection activities. The problem is addressed under the framework of reliability based optimization. The initiation and propagation of fatigue cracks are efficiently modeled using cohesive zone elements. The applicability of the method is demonstrated by a numerical example, which involves a plate with two holes subject to alternating stress. PMID:23564979

  15. Risk-based evaluation tool for safety-related maintenance involving scaffolding

    International Nuclear Information System (INIS)

    Stevens, C.; Azizi, M.; Massman, M.

    1988-01-01

    The US Nuclear Regulatory Commission (NRC) has expressed a general concern that transient materials in and around safety systems at nuclear power plants represent a seismic safety hazard to the plant, in particular, the uncontrolled use of scaffolding during maintenance activities. Currently, most plants perform a seismic safety analysis for all uses of scaffolding near safety-related equipment to determine appropriate tie-down locations, scaffolding reinforcements, etc. This is both time-consuming and, for the most part, unnecessary. A workable engineering solution based on risk analysis techniques has been developed and is being used at the Palo Verde nuclear generating station (PVNGS)

  16. Optimization of photovoltaic maintenance plan by means of a FMEA approach based on real data

    International Nuclear Information System (INIS)

    Villarini, Mauro; Cesarotti, Vittorio; Alfonsi, Lucrezia; Introna, Vito

    2017-01-01

    Highlights: • Application of RCM, based on FMEA, to photovoltaic systems. • MBS and FMEA determine RPN. • New maintenance plan aimed to reduce fixed RPN of criticalities. • Lower values of RPN by FMEA and major reliability of system obtained. - Abstract: There have been many scientific advances in the improvement of renewable energy systems. Recently, considerable interest has been given to their optimized management during their service life due to a large increase in the number of new renewable energy source power plants. High reliability levels are as important as high yields in order to maximize the useful green energy produced. Solar energy has been one of the most popular and exploited renewable sources in the market and therefore improvements in its efficiency and reliability have had a considerable impact. All energy systems require an increase in their conversion efficiency to reduce the consumption of primary energy. Moreover, the optimization of the performance of photovoltaic systems has increased their incidence as renewable sources in global power generation and has boosted their profitability. A failure of the components and sub-components of a working energy system cause two main issues; the first direct implication for the plant is the damage of the components and sub-components, and the second indirect implication is the consequent lack of energy production due to the plant being out of order. Furthermore, unforeseen failures of the components increase the uncontrollability of photovoltaic power systems, which worsens electric grid dispatching. The work presented here provides, for the first time, a complete and new assessment of Reliability Centered Maintenance carried out using a failure mode and effect analysis approach to photovoltaic systems. We use a large volume of data derived from a database of real maintenance activities carried out by a multinational company. These data were interpreted by the opinions of experts with specialist

  17. Research and Development of a Network-Based Intelligent Maintenance Information System

    Institute of Scientific and Technical Information of China (English)

    ZANG Tie-gang; YANG Ming-zhong; GUO Shun-sheng

    2003-01-01

    A maintenance information system is an important part of equipment management. An intelli gent maintenance information system ( IMIS) is a synthesis of network technology, information technology and intelligent technology. The IMIS is used to finish flexible maintenance decision-making and fast maintenance planning, which helps enterprises to effectively reduce maintenance cost and increase working efficiency. Because the IMIS integrates advanced technologies, its performance is better than a traditional one.The difference between an IMIS and a traditional maintenance information system, and the functions, structure, important realizations, and application of an IMIS are discussed in this paper.

  18. Bridge condition assessment based on long-term strain monitoring

    Science.gov (United States)

    Sun, LiMin; Sun, Shouwang

    2011-04-01

    In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

  19. Residual life management. Maintenance improvement

    International Nuclear Information System (INIS)

    Sainero Garcia, J.; Hevia Ruperez, F.

    1995-01-01

    The terms Residual Life Management, Life Cycle Management and Long-Term Management are synonymous with a concept which aims to establish efficient maintenance for the profitable and safe operation of a power plant for as long as possible. A Residual Life Management programme comprises a number of stages, of which Maintenance Evaluation focuses on how power plant maintenance practices allow the mitigation and control of component ageing. with this objective in mind, a methodology has been developed for the analysis of potential degradative phenomena acting on critical components in terms of normal power plant maintenance practices. This methodology applied to maintenance evaluation enables the setting out of a maintenance programme based on the Life Management concept, and the programme's subsequent up-dating to allow for new techniques and methods. Initial applications have shown that although, in general terms, power plant maintenance is efficient, the way in which Residual Life Management is approached requires changes in maintenance practices. These changes range from modifications to existing inspection and surveillance methods or the establishment of new ones, to the monitoring of trends or the performance of additional studies, the purpose of which is to provide an accurate evaluation of the condition of the installations and the possibility of life extension. (Author)

  20. Towards a Risk-based Decision Support for Offshore Wind Turbine Installation and Operation & Maintenance

    DEFF Research Database (Denmark)

    Gintautas, Tomas; Sørensen, John Dalsgaard; Vatne, Sigrid Ringdalen

    2016-01-01

    Costs of operation & maintenance, assembly, transport and installation of offshore wind turbines contribute significantly to the total cost of offshore wind farm. These operations are mostly carried out by specific ships that have to be hired for the operational phase and for duration of installa......Costs of operation & maintenance, assembly, transport and installation of offshore wind turbines contribute significantly to the total cost of offshore wind farm. These operations are mostly carried out by specific ships that have to be hired for the operational phase and for duration...... of installation process, respectively. Duration, and therefore ship hiring costs is, among others, driven by waiting time for weather windows for weather-sensitive operations. Today, state of the art decision making criteria for weather-sensitive operations are restrictions to the significant wave height...... and the average wind velocity at reference height. However, actual limitations are physical, related to response of equipment used e.g. crane wire tension, rotor assembly motions while lifting, etc. Transition from weather condition limits to limits on physical equipment response in decision making would improve...

  1. Pacific Northwest Laboratory Maintenance Implementation plan

    International Nuclear Information System (INIS)

    Bright, J.D.

    1992-06-01

    This Maintenance Implementation plan has been developed for Pacific Northwest Laboratory's (PNL) Nuclear Facilities: 306W, 324, 325, 327 and 329NMF. It is based on a graded approach, self-assessment of the existing maintenance program(s) per the requirements specified by US Department of Energy (DOE) Order 4330.4A, Chapter II, Change number-sign 3. The results of this assessment were evaluated to determine needed improvements in PNL Craft Services' current maintenance program. The objective of this implementation plan is to provide baseline information for compliance to the DOE 4330.4A, and for needed improvements. The prime consideration in applying a graded approach to the Order has been to maintain safe and reliable operations, environmental compliance, safeguards and security, programmatic mission, facility preservation, and/or other facility-specific requirements. Using the results of the self-assessment, PNL has selected nine of the 18 elements of the Maintenance Program defined by DOE Order 4330.4A for improvement. The elements selected for improvement are Training and Qualification of Maintenance Personnel; Maintenance Procedures; Planning, Scheduling, and Coordination of Maintenance; Control of Maintenance Activities; Post-Maintenance Testing; Facility Condition Inspection; Management Involvement; Maintenance History; and Additional Maintenance Requirements. Based upon graded approach and current funding, those elements considered most important have been selected as goals for earliest compliance. Commitment dates for these elements have been established for compliance. The remaining elements of noncompliance will be targeted for implementation during later budget periods

  2. Maintenance-based prognostics of nuclear plant equipment for long-term operation

    Energy Technology Data Exchange (ETDEWEB)

    Welz, Zachary; Coble, Jamie; Upadhyaya, Belle; Hines, Wes [University of Tennessee, Knoxville (United States)

    2017-08-15

    While industry understands the importance of keeping equipment operational and well maintained, the importance of tracking maintenance information in reliability models is often overlooked. Prognostic models can be used to predict the failure times of critical equipment, but more often than not, these models assume that all maintenance actions are the same or do not consider maintenance at all. This study investigates the influence of integrating maintenance information on prognostic model prediction accuracy. By incorporating maintenance information to develop maintenance-dependent prognostic models, prediction accuracy was improved by more than 40% compared with traditional maintenance-independent models. This study acts as a proof of concept, showing the importance of utilizing maintenance information in modern prognostics for industrial equipment.

  3. Data Base Development of Automobile and Light Truck Maintenance : Volume II. Appendix E.

    Science.gov (United States)

    1978-08-01

    The document contains the scheduled maintenance data sheets and total cost summaries--both scheduled and unscheduled maintenance (Life cycle cost for Dealers, life cycle cost for Service Stations, life cycle cost for Independent Repair, and scheduled...

  4. Data Base Development of Automobile and Light Truck Maintenance : Volume III. Appendix F.

    Science.gov (United States)

    1978-08-01

    The document contains the scheduled maintenance data sheets and total cost summaries--both scheduled and unscheduled maintenance (Life cycle cost for Dealers, life cycle cost for Service Stations, life cycle cost for Independent Repair, and scheduled...

  5. Advanced maintenance research programs

    International Nuclear Information System (INIS)

    Marston, T.U.; Gelhaus, F.; Burke, R.

    1985-01-01

    The purpose of this paper is to provide the reader with an idea of the advanced maintenance research program at the Electric Power Research Institute (EPRI). A brief description of the maintenance-related activities is provided as a foundation for the advanced maintenance research projects. The projects can be divided into maintenance planning, preventive maintenance program development and implementation, predictive (or conditional) maintenance, and innovative maintenance techniques. The projects include hardware and software development, human factors considerations, and technology promotion and implementation. The advanced concepts include: the incorporation of artificial intelligence into outage planning; turbine and pump maintenance; rotating equipment monitoring and diagnostics with the aid of expert systems; and the development of mobile robots for nuclear power plant maintenance

  6. Incorporation of Outcome-Based Contract Requirements in a Real Options Approach for Maintenance Planning

    Science.gov (United States)

    2016-04-30

    corrective maintenance (which increases as the RUL is used up), while maximizing the revenue earned during the RUL (which increases as the RUL is used up...running the system to failure, then performing corrective maintenance The value from exercising the option is the sum of the cumulative revenue loss...and the avoided corrective maintenance cost. The cumulative revenue loss is what the system would earn between the predictive maintenance event and

  7. Application and issues of online maintenance for equipment of nuclear power plants

    International Nuclear Information System (INIS)

    Higasa, Hisakazu

    2011-01-01

    The maintenance systems for long-term safety and repair costs reduction of equipment of nuclear power plants are stated. Planned maintenance contained the breakdown maintenance (BM) and the preventive maintenance, which consists of the time based maintenance (MBM) and the condition based maintenance (CBM). Explained are the characteristics of equipments, maintenance methods, maintenance solutions and the self-evaluation maintenance power, damage mechanism and solutions, and monitoring tools and application. Stated are the maintenance system and application of monitoring technology, periodical maintenance, application of diagnosis, vibration monitoring techniques, decision of vibration monitoring, and application of monitoring techniques for improvement of maintenance. Illustrated are realization of planned maintenance by reorganization of maintenance, a trend of maintenance of equipments, table of classified maintenance systems, change of maintenance program, maintenance data and investigation of damage mechanism, examples of self-evaluation maintenance power, examples of analysis of damage of parts of equipments, evaluation of rotating machines by vibration method, examples of results of diagnosis of bearing of rotating machines, online maintenance system of Asahi Kasei Engineering Corporation, degradation pattern of pomp, estimation of lifetime by total vibration and vibration on acceleration, and improvement of equipments. (S.Y.)

  8. Performance-based maintenance procurement by Dutch housing associations - Working paper ¿

    NARCIS (Netherlands)

    Straub, A.; van Mossel, H.J.

    2005-01-01

    Maintenance works are component services that are part of the final housing service to the tenant. Because main building maintenance works are designed each time again, it can be compared to product (service) development. With different types of cooperation with maintenance contractors, the degree

  9. Challenges of a community based pragmatic, randomised controlled trial of weight loss maintenance.

    Science.gov (United States)

    Randell, Elizabeth; McNamara, Rachel; Shaw, Christine; Espinasse, Aude; Simpson, Sharon Anne

    2015-12-18

    Randomised controlled trials (RCTs) have a reputation for being inherently difficult to deliver as planned and often face unforeseen challenges and delays, particularly in relation to organisational and governance difficulties, participant interest, constraints due to allocation of costs, local investigator interest and lengthy bureaucracy. Recruitment is often difficult and the challenges faced often impact on the cost and delivery of a successful trial within the funded period. This paper reflects upon the challenges faced in delivering a pragmatic RCT of weight loss maintenance in a community setting and suggests some potential solutions. The weight loss maintenance in adults trial aimed to evaluate the impact of a 12 month, individually tailored weight maintenance intervention on BMI 3 years from randomisation. Participants were recruited primarily from participant identification centres (PICs)-GP surgeries, exercise on referral schemes and slimming world. The intervention was delivered in community settings. A recruitment strategy implementation plan was drafted to address and monitor poor recruitment. Delays in opening and recruitment were experienced early on. Some were beyond the control of the study team such as; disagreement over allocation of national health service costs and PIC classification as well as difficulties in securing support from research networks. That the intervention was delivered in community settings was often at the root of these issues. Key items to address at the design stage of future trials include feasibility of eligibility criteria. The most effective element of the recruitment implementation plan was to refocus sources of recruitment and target only those who could fulfil the eligibility criteria immediately. Learnings from this trial should be kept in mind by those designing similar studies in the future. Considering potential governance, cost and research network support implications at the design stage of pragmatic trials of

  10. Priority of road maintenance management based on halda reading range on NAASRA method

    Science.gov (United States)

    Surbakti, M.; Doan, A.

    2018-02-01

    The road pavement, constantly experiencing stress-strain due to traffic load through it, can cause damage to the pavement. Therefore, early detection and repair of the damage will be able to prevent more severe damage that can develop into pavement failure. A road condition survey is one of the earliest attempts to detect the initial damage of a pavement. In this case the driving comfort is the most important part for the driver in assessing road conditions that are affected by the level of road surface roughness. To determine the level of roughness of the road, one of the methods developed is the measurement using the NAASRA method. In this method the roughness of the road is an accumulation of the average unevenness of the road, with the general setting on halda of 100 m. However, with this 100-meter setting, in some places the final value of the roughness value is too large or too small so that it will result in the priority of the road maintenance. This is what underlies roughness research by comparing halda settings at 50 m and 200 m different from the general settings above.This study uses the International Roughness Index (IRI) method in determining the level of road stability concerning driving discomfort. IRI score obtained from direct survey in field by using Roughometer-NAASRA.The final result shows that there is a significant difference between the reading of halda which is set at 100 m reading with halda set with 50 and 200 meter readings. This may lead to differences in handling priorities, which may impact on the sustainability of road network maintenance management (Sustainaible Road Management)

  11. Bearing Fault Classification Based on Conditional Random Field

    Directory of Open Access Journals (Sweden)

    Guofeng Wang

    2013-01-01

    Full Text Available Condition monitoring of rolling element bearing is paramount for predicting the lifetime and performing effective maintenance of the mechanical equipment. To overcome the drawbacks of the hidden Markov model (HMM and improve the diagnosis accuracy, conditional random field (CRF model based classifier is proposed. In this model, the feature vectors sequences and the fault categories are linked by an undirected graphical model in which their relationship is represented by a global conditional probability distribution. In comparison with the HMM, the main advantage of the CRF model is that it can depict the temporal dynamic information between the observation sequences and state sequences without assuming the independence of the input feature vectors. Therefore, the interrelationship between the adjacent observation vectors can also be depicted and integrated into the model, which makes the classifier more robust and accurate than the HMM. To evaluate the effectiveness of the proposed method, four kinds of bearing vibration signals which correspond to normal, inner race pit, outer race pit and roller pit respectively are collected from the test rig. And the CRF and HMM models are built respectively to perform fault classification by taking the sub band energy features of wavelet packet decomposition (WPD as the observation sequences. Moreover, K-fold cross validation method is adopted to improve the evaluation accuracy of the classifier. The analysis and comparison under different fold times show that the accuracy rate of classification using the CRF model is higher than the HMM. This method brings some new lights on the accurate classification of the bearing faults.

  12. Reliability Assessment and Reliability-Based Inspection and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramirez, José Rangel

    actions are the most relevant and effective means of control of deterioration. The risk-based inspection planning methodology, based on Bayesian decision theory, represents an important tool to identify the suitable strategy to inspect and control the deterioration in structures such as offshore wind...... performance during the life cycle. The deterioration processes, such as fatigue and corrosion, are typically affecting offshore structural systems. This damage decreases the system performance and increases the risk of failure, thus not fulfilling the established safety criteria. Inspection and maintenance...... to their offshore location, no pollution risks and low human risks since they are unmanned. This allows the allocation of lower reliability level compared to e.g. oil & gas installations. With the incursion to water depths between 20 and 50 meters, the use of jacket and tripod structures represents a feasible...

  13. Maintenance planning support method for nuclear power plants based on collective decision making

    International Nuclear Information System (INIS)

    Shimizu, Shunichi; Sakurai, Shoji; Takaoka, Kazushi; Kanemoto, Shigeru; Fukutomi, Shigeki

    1992-01-01

    Inspection and maintenance planning in nuclear power plants is conducted by decision making based on experts' collective consensus. However, since a great deal of time and effort is required to reach a consensus among expert judgments, the establishment of effective decision making methods is necessary. Therefore, the authors developed a method for supporting collective decision making, based on a combination of three types of decision making methods; the Characteristic Diagram method, Interpretative Structural Modeling method, and the Analytic Hierarchy Process method. The proposed method enables us to determine the evaluation criteria systematically for collective decision making, and also allows extracting collective decisions using simplified questionnaires. The proposed method can support reaching a consensus of groups effectively through the evaluation of collective decision structural models and their characteristics. In this paper, the effectiveness of the proposed method was demonstrated through its application to the decision making problem concerning whether or not the improved ultrasonic testing equipment should be adopted at nuclear power plants. (author)

  14. OPTIMIZING MAINTENANCE PROCESSES ON CUSTOMER SITE IN A DECENTRALIZED ORGANIZATION BASED ON MULTI-SITE TEAMS

    Directory of Open Access Journals (Sweden)

    Jorge Moutinho

    2015-03-01

    Full Text Available This lecture focuses on the complexity to manage and optimize maintenance processes, operations and service tasks to equipments and systems installed at customer sites. Different locations, access and working environment may compromise any standardization of setup's and operations. Multi-site teams based on geographic strategic locations, adds complexity to trainning, communication, supervising and monitoring processes. Logistics and information systems assume relevant rolls to consolidate global performance. Beside efficiency, effectiveness productivity and flexibility, field teams need skills on autonomy responsibility and proactivity. This lecture also explores the needed adaptation of most part of available literature, normally based on production sites, as also of Lean- Kaizen principles to the fact that services can not be stocked, quality is normally more difficult to measure and customer is normally present when and where service is produced.

  15. Evaluation of artillery equipment maintenance support capability based on grey clustering

    Science.gov (United States)

    Zhai, Mei-jie; Gao, Peng

    2017-12-01

    This paper, the theory and method of evaluating the capability of equipment maintenance support in China and abroad are studied, from the point of view of the combat task of artillery troops and the strategic attachment in the future military struggle. This paper establishes the framework of the evaluation Index system of the equipment maintenance support capability of the artillery units, and applies the grey clustering method to the evaluation of the equipment maintenance support capability of the artillery units, and finally evaluates the equipment maintenance and support capability of the artillery brigade as an example, and analyzes the evaluation results. This paper finds out the outstanding problems existing in the maintenance and support of military equipment, and puts forward some constructive suggestions, in order to improve the status of military equipment maintenance and support and improve the level of future equipment maintenance.

  16. Ethnicity- and sex-based discrimination and the maintenance of self-esteem.

    Science.gov (United States)

    Lönnqvist, Jan-Erik; Hennig-Schmidt, Heike; Walkowitz, Gari

    2015-01-01

    The psychological underpinnings of labor market discrimination were investigated by having participants from Israel, the West Bank and Germany (N = 205) act as employers in a stylized employment task in which they ranked, set wages, and imposed a minimum effort level on applicants. State self-esteem was measured before and after the employment task, in which applicant ethnicity and sex were salient. The applicants were real people and all behavior was monetarily incentivized. Supporting the full self-esteem hypothesis of the social identity approach, low self-esteem in women was associated with assigning higher wages to women than to men, and such behavior was related to the maintenance of self-esteem. The narrower hypothesis that successful intergroup discrimination serves to protect self-esteem received broader support. Across all participants, both ethnicity- and sex-based discrimination of out-groups were associated with the maintenance of self-esteem, with the former showing a stronger association than the latter.

  17. No functional role of attention-based rehearsal in maintenance of spatial working memory representations.

    Science.gov (United States)

    Belopolsky, Artem V; Theeuwes, Jan

    2009-10-01

    The present study systematically examined the role of attention in maintenance of spatial representations in working memory as proposed by the attention-based rehearsal hypothesis [Awh, E., Jonides, J., & Reuter-Lorenz, P. A. (1998). Rehearsal in spatial working memory. Journal of Experimental Psychology--Human Perception and Performance, 24(3), 780-790]. Three main issues were examined. First, Experiments 1-3 demonstrated that inhibition and not facilitation of visual processing is often observed at the memorized location during the retention interval. This inhibition was caused by keeping a location in memory and not by the exogenous nature of the memory cue. Second, Experiment 4 showed that inhibition of the memorized location does not lead to any significant impairment in memory accuracy. Finally, Experiment 5 connected current results to the previous findings and demonstrated facilitation of processing at the memorized location. Importantly, facilitation of processing did not lead to more accurate memory performance. The present results challenge the functional role of attention in maintenance of spatial working memory representations.

  18. Ethnicity- and Sex-Based Discrimination and the Maintenance of Self-Esteem

    Science.gov (United States)

    2015-01-01

    The psychological underpinnings of labor market discrimination were investigated by having participants from Israel, the West Bank and Germany (N = 205) act as employers in a stylized employment task in which they ranked, set wages, and imposed a minimum effort level on applicants. State self-esteem was measured before and after the employment task, in which applicant ethnicity and sex were salient. The applicants were real people and all behavior was monetarily incentivized. Supporting the full self-esteem hypothesis of the social identity approach, low self-esteem in women was associated with assigning higher wages to women than to men, and such behavior was related to the maintenance of self-esteem. The narrower hypothesis that successful intergroup discrimination serves to protect self-esteem received broader support. Across all participants, both ethnicity- and sex-based discrimination of out-groups were associated with the maintenance of self-esteem, with the former showing a stronger association than the latter. PMID:25978646

  19. Program integration of predictive maintenance with reliability centered maintenance

    International Nuclear Information System (INIS)

    Strong, D.K. Jr; Wray, D.M.

    1990-01-01

    This paper addresses improving the safety and reliability of power plants in a cost-effective manner by integrating the recently developed reliability centered maintenance techniques with the traditional predictive maintenance techniques of nuclear power plants. The topics of the paper include a description of reliability centered maintenance (RCM), enhancing RCM with predictive maintenance, predictive maintenance programs, condition monitoring techniques, performance test techniques, the mid-Atlantic Reliability Centered Maintenance Users Group, test guides and the benefits of shared guide development

  20. Improving the TRIGA facility maintenance by predictive maintenance techniques

    International Nuclear Information System (INIS)

    Preda, M.; Sabau, C.; Barbalata, E.

    1997-01-01

    This work deals with the specific operation of equipment in radioactive environment or in conditions allowing radioactive contamination. The requirements of remote operation ensuring the operators' protection are presented. Also, the requirements of international standards issued by IAEA-Vienna are reviewed. The organizational withdraws of the maintenance activities, based on the standards and maintenance and repair directives still in force, are shown. It is emphasized the fact that this type of maintenance was adequate to a given level of technical development, characteristic for pre-computerized industry, but, at present, it is obsolete and uneconomic both in utilization and maintenance. Such a system constitutes already a burden hindering the efforts of maximizing the availability, maintenance, prolongation the service life of equipment and utilities, finally, of increasing the efficiency of complex installations. Moreover, the predictive maintenance techniques are strongly requested by the character of radioactive installations precluding the direct access in given zones (a potential risk of irradiation or radioactive contamination) of installations during operation. The results obtained by applying the predictive maintenance techniques in the operation of the double circuit irradiation loop, used in the TRIGA reactors, are presented

  1. Using stationary image based data collection method for evaluation of traffic sign condition

    Directory of Open Access Journals (Sweden)

    Majid Khalilikhah

    2016-12-01

    Full Text Available Transportation asset management helps monitor the transportation systems and optimize the construction, operation, and maintenance of assets. Many state Department of Transportations (DOTs have already established asset management systems for high cost and low quantity assets, e.g., bridge and tunnel assets. However, due to the sheer number of traffic signs deployed by DOTs, statewide sign inventory and condition information are not well developed. Currently, using handheld devices is the most selected method by agencies to measure signs. To address safety challenge and high cost of data collection, an innovative stationary image based method has recently been proposed. This paper discusses the advantages and disadvantages of such image based method over using handheld devices in terms of the accuracy, possibility and consistency of data, speed, safety, maintenance, and cost. At its completion, this study provides suggestions to tackle the issues associated with image based method.

  2. Heuristic guidelines and experimental evaluation of effective augmented-reality based instructions for maintenance in nuclear power plants

    International Nuclear Information System (INIS)

    Yim, Ho Bin; Seong, Poong Hyun

    2010-01-01

    Research highlights: → Augmented reality (AR) instructions were built for NPPs maintenance personnel. → 4-5 pieces of information at a time were optimum for AR instructions in this study. → A large variance in mode no. 5 implies these were also found to be critical amount. → Heuristic guidelines were suggested to make AR instructions more effective. - Abstract: As industrial plants and factories age, their maintenance requirements increase. Because maintenance mistakes directly increase the operating costs of a power plant, maintenance quality is significant concern to plant management. By law, all personnel working with nuclear technology must be re-trained every three years in Korea; however, as the statistical data show, the number of shutdown accidents at nuclear power plants (NPPs) due to maintenance failure is still high and needs to be reduced. Industries have started to adopt various technologies to increase the speed and accuracy of maintenance. Among those technologies, augmented reality (AR) is the latest multimedia presentation technology to be applied to plant maintenance, and it offers superior intuitiveness and user interactivity over other conventional multimedia. This empirical study aims to measure the optimum amounts of information to be delivered at a time and to identify what types of information enhance the learning ability of novices and to suggest heuristic guidelines by which to make effective AR training instructions. In the first experiment, the optimum amount of information in an AR learning environment for novices was found to be 4-5 pieces of information in a chunk by comparing results between a pre-test and an after-test. This result implies that intentionally made chunks help novices learn more effectively. In the second experiment, the AR training instruction based on the suggested heuristic guidelines was slightly more effective than other AR training instructions. Maintenance in nuclear power plants can be more reliable

  3. Development of diagnosis and maintenance support system for nuclear power plants with flexible inference function and knowledge base edition support function

    International Nuclear Information System (INIS)

    Fujii, Makoto; Seki, Eiji; Tai, Ichiro; Morioka, Toshihiko

    1988-01-01

    For the reliable and efficient diagnosis and inspection work of the nuclear power plant equipments, 'Diagnosis and Maintenance Support System' has been developed. This system has functions to assist operators or engineers to observe and evaluate equipment conditions based on the experts' knowledge. These functions are carried out through dialogue between the system and users. This system has two subsystems: diagnosis subsystem and knowledge base edition support subsystem. To achieve the functions of diagnosis subsystem, a new method of knowledge processing for equipment diagnosis is adopted. This method is based on the concept of 'Cause Generation and Checking'. Knowledge for diagnosis is represented with modularized production rules. And each rule module consists of four different type rules with hierarchical structure. With this approach, the system is equipped with sufficient performance not only in diagnosis function but also in flexible man-machine interface. Knowledge base edition support subsystem (Graphical Rule Editor) is provided for this system. This editor has functions to display and edit the contents of knowledge base with tree structures through the graphic display. With these functions, the efficiency of constructing expert system is highly improved. By applying this system to the maintenance support of neutron monitoring system, it is proved that this system has satisfactory performance as a diagnosis and maintenance support system. (author)

  4. Conference on the exploitation, maintenance and resale of ground-based photovoltaic plants

    International Nuclear Information System (INIS)

    Roesner, Sven; Christmann, Ralf; Bozonnat, Cedric; Le Pivert, Xavier; Vaassen, Willi; Dumoulin, Cedric; Kiefer, Klaus; Semmel, Andreas; Doose, Eckhard; Bion, Alain; Sanches, Frederico; Daval, Xavier; Pampouille, Antoine; Goetze, Holger; Stahl, Wolf-Ruediger; Merere, Karine

    2017-11-01

    This document gathers contributions and debate contents of a conference. A first set of contributions addressed the situation and recent developments of ground-based photovoltaic power plants in France and in Germany with presentations of legal frameworks in these both countries. The second set addressed the optimisation of such power plants: meteorological prediction and follow-up at the service of production, risks to which these power plants are exposed during operation, and the issue of right price and good practices for maintenance contracts for these plants. A round table addressed the issue of the balance between optimisation and established practices in a new economic framework. The next set of contributions addressed reasons for and effects of the resale of photovoltaic fleet during their exploitation: actors and financing solutions, value components, point of attention and legal view on re-financing contracts. A round table discussed trends and success factors for the re-financing of photovoltaic projects

  5. Fault Detection for Large-Scale Railway Maintenance Equipment Base on Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Junfu Yu

    2014-04-01

    Full Text Available Focusing on the fault detection application for large-scale railway maintenance equipment with the specialties of low-cost, energy efficiency, collecting data of the function units. This paper proposed energy efficiency, convenient installation fault detection application using Sigsbee wireless sensor networks, which Sigsbee is the most widely used protocol based on IEEE 802.15.4. This paper proposed a systematic application from hardware design using STM32F103 chips as processer, to software system. Fault detection application is the basic part of the fault diagnose system, wireless sensor nodes of the fault detection application with different kinds of sensors for verities function units communication by Sigsbee to collecting and sending basic working status data to the home gateway, then data will be sent to the fault diagnose system.

  6. The use of advanced scale conditioning agents for maintenance of the secondary side of nuclear plant steam generators

    International Nuclear Information System (INIS)

    Battaglia, P.J.; Rogosky, D.L.

    2006-01-01

    Maintaining the secondary side of steam generators within a pressurized water reactor (PWR) free of deposited corrosion products and corrosion-inducing contaminants is key to ensuring their long-term operation. New cleaning processes have become available to aid nuclear plant personnel in optimizing secondary side maintenance strategies. These strategies include both maintaining nuclear steam generators corrosion free while maintaining full power operation. The conference presentation will discuss ASCA use and the major field experience acquired in the last several years in the United States and in Japan. Hokkaido Electric, Dominion Engineering, Inc. and Westinghouse cosponsored the development of ASCAs for use in the Nuclear Utility industry, and all three are active in field use programs. Westinghouse owns the worldwide rights for ASCA implementation except in Japan where MHI and NEL have been granted licenses to apply ASCAs. Dominion Engineering Inc., owns the ASCA patents and performs the laboratory qualification testing associated with the ASCA programs, and Hokkaido Electric are joint patent holders for ASCAs and have been implementing their use at the Tomari plants for cleaning and thermal hydraulic performance enhancements. The specific experience discussed in the presentation will include: 1. Full Bundle Maintenance ASCAs at Vogtle Units 2 and 2 and Wolf Creek (USA). 2. Top of the Tubesheet ASCAs with high pressure sludge lancing at Wolf Creek and UEC at Vogtle Units 1 and 2 (USA). 3. Thermal Hydraulic Recovery and Maintenance ASCAs at the Hokkaido Electric Tomari Units 1 and 2 (Japan). (author)

  7. A fuzzy knowledge based method for maintenance planning in a power system

    International Nuclear Information System (INIS)

    Sergaki, Amalia; Kalaitzakis, Kostas

    2002-01-01

    The inspection planning in electric power industry is used to assess the safety and reliability of system components and to increase the ability of failure situation identification before it actually occurs. It reflects the implications of the available information on the operational and maintenance history of the system. The output is a ranked list of components, with the most critical ones at the top, which indicates the selection of the components to be inspected. In this paper, we demonstrate the use of a fuzzy relational database model for manipulating the data required for the criticality component ranking in thermal power systems inspection planning, incorporating criteria concerning aspects of safety and reliability, economy, variable operational conditions and environmental impacts. Often, qualitative thresholds and linguistic terms are used for the component criticality analysis. Fuzzy linguistic terms for criteria definitions along with fuzzy inference mechanisms allow the exploitation of the operators' expertise. The proposed database model ensures the representation and handling of the aforementioned fuzzy information and additionally offers to the user the functionality for specifying the precision degree by which the conditions involved in a query are satisfied. In order to illustrate the behavior of the model, a case study is given using real inspection data

  8. Developing optimized prioritizing road maintenance

    Directory of Open Access Journals (Sweden)

    Ewadh Hussein Ali

    2018-01-01

    Full Text Available Increased demand for efficient maintenance of the existing roadway system needs optimal usage of the allocated funds. The paper demonstrates optimized methods for prioritizing maintenance implementation projects. A selected zone of roadway system in Kerbala city represents the study area to demonstrate the application of the developed prioritization process. Paver system PAVER integrated with GIS is used to estimate and display the pavement condition index PCI, thereby to establish a priority of maintenance. In addition to simple ranking method by PCI produced by the output of PAVER, the paper introduces PCI measure for each section of roadway. The paper introduces ranking by multiple measures investigated through expert knowledge about measures that affect prioritization and their irrespective weights due to a predesigned questionnaire. The maintenance priority index (MPI is related to cost of suitable proposed maintenance, easiness of proposed maintenance, average daily traffic and functional classification of the roadway in addition to PCI. Further, incremental benefit-cost analysis ranking provide an optimized process due to benefit and cost of maintenance. The paper introduces efficient display of layout and ranking for the selected zone of roadway system based on MPI index and incremental BCR method. Although the two developed methods introduce different layout display for priority, statistical test shows that no significant difference between ranking of all methods of prioritization.

  9. Using Field Data for Energy Efficiency Based on Maintenance and Operational Optimisation. A Step towards PHM in Process Plants

    Directory of Open Access Journals (Sweden)

    Micaela Demichela

    2018-03-01

    Full Text Available Energy saving is an important issue for any industrial sector; in particular, for the process industry, it can help to minimize both energy costs and environmental impact. Maintenance optimization and operational procedures can offer margins to increase energy efficiency in process plants, even if they are seldom explicitly taken into account in the predictive models guiding the energy saving policies. To ensure that the plant achieves the desired performance, maintenance operations and maintenance results should be monitored, and the connection between the inputs and the outcomes of the maintenance process, in terms of total contribution to manufacturing performance, should be explicit. In this study, a model for the energy efficiency analysis was developed, based on cost and benefits balance. It is aimed at supporting the decision making in terms of technical and operational solutions for energy efficiency, through the optimization of maintenance interventions and operational procedures. A case study is here described: the effects on energy efficiency of technical and operational optimization measures for bituminous materials production process equipment. The idea of the Conservation Supply Curve (CSC was used to capture both the cost effectiveness of the measures and the energy efficiency effectiveness. The optimization was thus based on the energy consumption data registered on-site: data collection and modelling of the relevant data were used as a base to implement a prognostic and health management (PHM policy in the company. Based on the results from the analysis, efficiency measures for the industrial case study were proposed, also in relation to maintenance optimization and operating procedures. In the end, the impacts of the implementation of energy saving measures on the performance of the system, in terms of technical and economic feasibility, were demonstrated. The results showed that maintenance optimization could help in reaching

  10. Costs of performance based maintenance for local roads: Case study Albania

    OpenAIRE

    Jokanović Igor; Grujić Bojana; Zeljić Dragana; Grujić Žarko; Svilar Mila

    2017-01-01

    The provision and maintenance of road infrastructure is a major global business, consequently it is essential that road maintenance services are provided in the most cost effective manner. Without regular maintenance, roads can rapidly fall into disrepair, preventing realization of the longer term impacts of road improvements on development, such as increased agricultural production and growth in school enrollment, which is of particular importance for a network of local (access) roads. Inade...

  11. A Costing Analysis for Decision Making Grid Model in Failure-Based Maintenance

    OpenAIRE

    M. A., Burhanuddin; Halawani, Sami M.; Ahmad, A. R.

    2011-01-01

    Background. In current economic downturn, industries have to set good control on production cost, to maintain their profit margin. Maintenance department as an imperative unit in industries should attain all maintenance data, process information instantaneously, and subsequently transform it into a useful decision. Then act on the alternative to reduce production cost. Decision Making Grid model is used to identify strategies for maintenance decision. However, the model has limitation as it c...

  12. Decommissioning and Dismantling of the Floating Maintenance Base 'Lepse' - 13316

    Energy Technology Data Exchange (ETDEWEB)

    Field, D.; Mizen, K. [Nuvia Limited (United Kingdom)

    2013-07-01

    The Lepse was built in Russia in 1934 and commissioned as a dry cargo ship. In 1961 she was re-equipped for use as a nuclear service ship (NSS), specifically a floating maintenance base (FMB), to support the operation of the civilian nuclear fleet (ice-breakers) of the USSR. In 1988 Lepse was taken out of service and in 1990 she was re-classified as a 'berth connected ship', located at a berth near the port of Murmansk under the ownership of Federal State Unitary Enterprise (FSUE) Atomflot. Lepse has special storage facilities for spent nuclear fuel assemblies (SFA) that have been used to store several hundred SFAs for nearly 40 years. High and intermediate-level liquid radioactive waste (LRW) is also present in the spent nuclear fuel assembly storage channels, in special tanks and also in the SFA cooling circuit. Many of the SFAs stored in Lepse are classified as damaged and cannot be removed using standard procedures. The removal of the SFA and LRW from the Lepse storage facilities is a hazardous task and requires specially designed tools, equipment and an infrastructure in which these can be deployed safely. Lepse is a significant environmental hazard in the North West of Russia. Storing spent nuclear fuel and high-level liquid radioactive waste on board Lepse in the current conditions is not acceptable with respect to Russian Federation health, safety and environmental standards and with international best practice. The approved concept design for the removal of the SFA and LRW and dismantling of Lepse requires that the ship be transported to Nerpa shipyard where specialist infrastructure will be constructed and equipment installed. One of the main complexities of the Project lies within the number of interested stakeholders involved in the Project. The Lepse project has been high focus on the international stage for many years with previous international efforts failing to make significant progress towards the objective of decommissioning Lepse. The

  13. Optimization of surface maintenance

    International Nuclear Information System (INIS)

    Oeverland, E.

    1990-01-01

    The present conference paper deals with methods of optimizing the surface maintenance of steel-made offshore installations. The paper aims at identifying important approaches to the problems regarding the long-range planning of an economical and cost effective maintenance program. The methods of optimization are based on the obtained experiences from the maintenance of installations on the Norwegian continental shelf. 3 figs

  14. A risk based model supporting long term maintenance and reinvestment strategy decision making

    Energy Technology Data Exchange (ETDEWEB)

    Sand, Kjell; Montard, Julien; Tremoen, Tord H.

    2010-02-15

    This Technical Report is a product from the project Risk-Based Distribution System Asset Management (short: RISK DSAM) - Work Package 3 Risk exposure on company/strategic level. In the report a concept for portfolio distribution system asset management is presented. The approach comprises four main steps: 1. Decide the asset base. 2. Divide the asset base into relevant archetypes. 3. Develop or select relevant maintenance and reinvestment strategies for the different archetypes. 4. Estimate risks and costs for each archetype for the relevant strategies. For the different steps guidelines are given and a proposal for implementation of the concept is given in terms of a proposed IT system architecture.To evaluate the feasibility of such a concept, a prototype was developed in by using Visual Basic macros in Excel using real technical data from a small DSO. The experience from using the prototype shows that the concept is realistic. All assets are included and depending of the ambition of the risk analysis both simple simulation models and more advanced might be embedded. Presentations of the concept for a utility engineers have receive positive feedback indicating that the concept is regarded as a practical way to develop risk based asset management strategies for the asset fleet. It should be noted that the concept should be applied on a company strategic level and is thus not designed to be applied for a specific project or asset decisions. For this, more detailed models with area specific information, topology etc. are needed. (Author)

  15. AIRCRAFT MAINTENANCE HANGAR

    Directory of Open Access Journals (Sweden)

    GEAMBASU Gabriel George

    2017-05-01

    Full Text Available The paper presents the maintenance process that is done on an airplane, at a certain period of time, or after a number of flight hours or cycles and describes the checks performed behind each inspection. The first part of research describes the aircraft maintenance process that has to be done after an updated maintenance manual according with aircraft type, followed by a short introduction about maintenance hangar. The second part of the paper presents a hangar design with a foldable roof and walls, which can be folded or extended, over an airplane when a maintenance process is done, or depending on weather condition.

  16. Condition Monitoring for Roller Bearings of Wind Turbines Based on Health Evaluation under Variable Operating States

    Directory of Open Access Journals (Sweden)

    Lei Fu

    2017-10-01

    Full Text Available Condition monitoring (CM is used to assess the health status of wind turbines (WT by detecting turbine failure and predicting maintenance needs. However, fluctuating operating conditions cause variations in monitored features, therefore increasing the difficulty of CM, for example, the frequency-domain analysis may lead to an inaccurate or even incorrect prediction when evaluating the health of the WT components. In light of this challenge, this paper proposed a method for the health evaluation of WT components based on vibration signals. The proposed approach aimed to reduce the evaluation error caused by the impact of the variable operating condition. First, the vibration signal was decomposed into a set of sub-signals using variational mode decomposition (VMD. Next, the sub-signal energy and the probability distribution were obtained and normalized. Finally, the concept of entropy was introduced to evaluate the health condition of a monitored object to provide an effective guide for maintenance. In particular, the health evaluation for CM was based on a performance review over a range of operating conditions, rather than at a certain single operating condition. Experimental investigations were performed which verified the efficiency of the evaluation method, as well as a comparison with the previous method.

  17. A dynamic predictive maintenance policy for complex multi-component systems

    International Nuclear Information System (INIS)

    Van Horenbeek, Adriaan; Pintelon, Liliane

    2013-01-01

    The use of prognostic methods in maintenance in order to predict remaining useful life is receiving more attention over the past years. The use of these techniques in maintenance decision making and optimization in multi-component systems is however a still underexplored area. The objective of this paper is to optimally plan maintenance for a multi-component system based on prognostic/predictive information while considering different component dependencies (i.e. economic, structural and stochastic dependence). Consequently, this paper presents a dynamic predictive maintenance policy for multi-component systems that minimizes the long-term mean maintenance cost per unit time. The proposed maintenance policy is a dynamic method as the maintenance schedule is updated when new information on the degradation and remaining useful life of components becomes available. The performance, regarding the objective of minimal long-term mean cost per unit time, of the developed dynamic predictive maintenance policy is compared to five other conventional maintenance policies, these are: block-based maintenance, age-based maintenance, age-based maintenance with grouping, inspection condition-based maintenance and continuous condition-based maintenance. The ability of the predictive maintenance policy to react to changing component deterioration and dependencies within a multi-component system is quantified and the results show significant cost savings

  18. A methodology based in particle swarm optimization algorithm for preventive maintenance focused in reliability and cost

    International Nuclear Information System (INIS)

    Luz, Andre Ferreira da

    2009-01-01

    In this work, a Particle Swarm Optimization Algorithm (PSO) is developed for preventive maintenance optimization. The proposed methodology, which allows the use flexible intervals between maintenance interventions, instead of considering fixed periods (as usual), allows a better adaptation of scheduling in order to deal with the failure rates of components under aging. Moreover, because of this flexibility, the planning of preventive maintenance becomes a difficult task. Motivated by the fact that the PSO has proved to be very competitive compared to other optimization tools, this work investigates the use of PSO as an alternative tool of optimization. Considering that PSO works in a real and continuous space, it is a challenge to use it for discrete optimization, in which scheduling may comprise variable number of maintenance interventions. The PSO model developed in this work overcome such difficulty. The proposed PSO searches for the best policy for maintaining and considers several aspects, such as: probability of needing repair (corrective maintenance), the cost of such repairs, typical outage times, costs of preventive maintenance, the impact of maintaining the reliability of systems as a whole, and the probability of imperfect maintenance. To evaluate the proposed methodology, we investigate an electro-mechanical system consisting of three pumps and four valves, High Pressure Injection System (HPIS) of a PWR. Results show that PSO is quite efficient in finding the optimum preventive maintenance policies for the HPIS. (author)

  19. Study on risk-based operation and maintenance using the living PSA system

    International Nuclear Information System (INIS)

    Kurisaka, K.

    2000-01-01

    The objective of this study is to contribute to an improvement of fast reactor plant operation and maintenance from the standpoint of risk assessment. An effort was made to analyze a relationship between the valve failure probability and the standby time based on the component reliability database and statistical analysis system (CORDS). According to the analysis result, the following issues were examined: the surveillance test interval (STI), timing and the allowable outage time (AOT) of redundant valve system in a fast reactor model plant. An examination was performed based on the failure probability non-linearly dependent on the standby time using the risk importance measures and technique to optimize the AOT which are incorporated in the living PSA system (LIPSAS). The case study showed that consideration of non-linear time trend of the failure probability made the recommended STI and AOT longer under the same risk limitation. It is recommended to apply the nonlinear expression of demand failure probability in estimating the STI and AOT based on the risk measures. (author)

  20. Designing a future Conditions Database based on LHC experience

    CERN Document Server

    Formica, Andrea; The ATLAS collaboration; Gallas, Elizabeth; Govi, Giacomo; Lehmann Miotto, Giovanna; Pfeiffer, Andreas

    2015-01-01

    The ATLAS and CMS Conditions Database infrastructures have served each of the respective experiments well through LHC Run 1, providing efficient access to a wide variety of conditions information needed in online data taking and offline processing and analysis. During the long shutdown between Run 1 and Run 2, we have taken various measures to improve our systems for Run 2. In some cases, a drastic change was not possible because of the relatively short time scale to prepare for Run 2. In this process, and in the process of comparing to the systems used by other experiments, we realized that for Run 3, we should consider more fundamental changes and possibilities. We seek changes which would streamline conditions data management, improve monitoring tools, better integrate the use of metadata, incorporate analytics to better understand conditions usage, as well as investigate fundamental changes in the storage technology, which might be more efficient while minimizing maintenance of the data as well as simplif...

  1. Prediction of Combine Economic Life Based on Repair and Maintenance Costs Model

    Directory of Open Access Journals (Sweden)

    A Rohani

    2014-09-01

    Full Text Available Farm machinery managers often need to make complex economic decisions on machinery replacement. Repair and maintenance costs can have significant impacts on this economic decision. The farm manager must be able to predict farm machinery repair and maintenance costs. This study aimed to identify a regression model that can adequately represent the repair and maintenance costs in terms of machine age in cumulative hours of use. The regression model has the ability to predict the repair and maintenance costs for longer time periods. Therefore, it can be used for the estimation of the economic life. The study was conducted using field data collected from 11 John-Deer 955 combine harvesters used in several western provinces of Iran. It was found that power model has a better performance for the prediction of combine repair and maintenance costs. The results showed that the optimum replacement age of John-Deer 955 combine was 54300 cumulative hours.

  2. Outcomes From Pediatric Gastroenterology Maintenance of Certification Using Web-based Modules.

    Science.gov (United States)

    Sheu, Josephine; Chun, Stanford; O'Day, Emily; Cheung, Sara; Cruz, Rusvelda; Lightdale, Jenifer R; Fishman, Douglas S; Bousvaros, Athos; Huang, Jeannie S

    2017-05-01

    Beginning in 2013, the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) sponsored and developed subspecialty field-specific quality improvement (QI) activities to provide Part 4 Maintenance of Certification (MOC) credit for ongoing certification of pediatric gastroenterologists by the American Board of Pediatrics. Each activity was a Web-based module that measured clinical practice data repeatedly over at least 3 months as participants implemented rapid cycle change. Here, we examine existing variations in clinical practice among participating pediatric gastroenterologists and determine whether completion of Web-based MOC activities improves patient care processes and outcomes. We performed a cross-sectional and prospective analysis of physician and parent-reported clinical practice data abstracted from Web-based MOC modules on the topics of upper endoscopy, colonoscopy, and informed consent collected from pediatric gastroenterologists from North America from 2013 to 2016. Among 134 participating pediatric gastroenterologists, 56% practitioners practiced at an academic institution and most (94%) were NASPGHAN members. Participating physicians reported data from 6300 procedures. At baseline, notable practice variation across measured activities was demonstrated. Much of the rapid cycle changes implemented by participants involved individual behaviors, rather than system/team-based improvement activities. Participants demonstrated significant improvements on most targeted process and quality care outcomes. Pediatric gastroenterologists and parents reported baseline practice variation, and improvement in care processes and outcomes measured during NASPGHAN-sponsored Web-based MOC QI activities. Subspecialty-oriented Web-based MOC QI activities can reveal targets for reducing unwarranted variation in clinical pediatric practice, and can effectively improve care and patient outcomes.

  3. Development of transport mechanical engineering as the condition of maintenance of social and economic security of region

    Directory of Open Access Journals (Sweden)

    Vsevolod Petrovich Babushkin

    2012-12-01

    Full Text Available In the article, the transport role in the decision of problems of innovative and scientifically-technological development of territory is defined. Dependence of quality, completeness and timeliness of granting of transport services on replenishment and updating of park of locomotives, cars, i.e. from a level of development of domestic transport mechanical engineering is shown. The basic problems of development given branches –low competitiveness of made production are revealed. The basic accent in the course of such analysis is made on research of competitive possibilities of the enterprises of railway mechanical engineering of Sverdlovsk area. Such enterprises play the increasing role, become points of development of region’s economy and maintenance of its social and economic safety. The cooperation communications, which have developed in an industrial complex of Sverdlovsk area on the basis of development of modern manufacture on building of electric locomotives, have allowed to generate in region cluster railway mechanical engineering. The structure cluster is shown, development prospects, the estimation of its influence on the economy of Sverdlovsk area and maintenance of its social and economic security is given

  4. Signal Analysis of Automotive Engine Spark Ignition System using Case-Based Reasoning (CBR) and Case-based Maintenance (CBM)

    International Nuclear Information System (INIS)

    Huang, H.; Vong, C. M.; Wong, P. K.

    2010-01-01

    With the development of modern technology, modern vehicles adopt electronic control system for injection and ignition. In traditional way, whenever there is any malfunctioning in an automotive engine, an automotive mechanic usually performs a diagnosis in the ignition system of the engine to check any exceptional symptoms. In this paper, we present a case-based reasoning (CBR) approach to help solve human diagnosis problem. Nevertheless, one drawback of CBR system is that the case library will be expanded gradually after repeatedly running the system, which may cause inaccuracy and longer time for the CBR retrieval. To tackle this problem, case-based maintenance (CBM) framework is employed so that the case library of the CBR system will be compressed by clustering to produce a set of representative cases. As a result, the performance (in retrieval accuracy and time) of the whole CBR system can be improved.

  5. Explaining variations in state foster care maintenance rates and the implications for implementing new evidence-based programs

    Science.gov (United States)

    Goldhaber-Fiebert, Jeremy D.; Babiarz, Kimberly S.; Garfield, Rachel L.; Wulczyn, Fred; Landsverk, John; Horwitz, Sarah M.

    2013-01-01

    Background U.S. Child Welfare systems are involved in the lives of millions of children, and total spending exceeds $26 billion annually. Out-of-home foster care is a critical and expensive Child Welfare service, a major component of which is the maintenance rate paid to support housing and caring for a foster child. Maintenance rates vary widely across states and over time, but reasons for this variation are not well understood. As evidence-based programs are disseminated to state Child Welfare systems, it is important to understand what may be the important drivers in the uptake of these practices including state spending on core system areas. Data and methods We assembled a unique, longitudinal, state-level panel dataset (1990–2008) for all 50 states with annual data on foster care maintenance rates and measures of child population in need, poverty, employment, urbanicity, proportion minority, political party control of the state legislature and governorship, federal funding, and lawsuits involving state foster care systems. All monetary values were expressed in per-capita terms and inflation adjusted to 2008 dollars. We used longitudinal panel regressions with robust standard errors and state and year fixed effects to estimate the relationship between state foster care maintenance rates and the other factors in our dataset, lagging all factors by one year to mitigate the possibility that maintenance rates influenced their predictors. Exploratory analyses related maintenance rates to Child Welfare outcomes. Findings State foster care maintenance rates have increased in nominal terms, but in many states, have not kept pace with inflation, leading to lower real rates in 2008 compared to those in 1991 for 54% of states for 2 year-olds, 58% for 9 year-olds, and 65% for 16 year-olds. In multivariate analyses including socioeconomic, demographic, and political factors, monthly foster care maintenance rates declined $15 for each 1% increase in state unemployment and

  6. Condition Monitoring for DC-link Capacitors Based on Artificial Neural Network Algorithm

    DEFF Research Database (Denmark)

    Soliman, Hammam Abdelaal Hammam; Wang, Huai; Gadalla, Brwene Salah Abdelkarim

    2015-01-01

    hardware will reduce the cost, and therefore could be more promising for industry applications. A condition monitoring method based on Artificial Neural Network (ANN) algorithm is therefore proposed in this paper. The implementation of the ANN to the DC-link capacitor condition monitoring in a back......In power electronic systems, capacitor is one of the reliability critical components . Recently, the condition monitoring of capacitors to estimate their health status have been attracted by the academic research. Industry applications require more reliable power electronics products...... with preventive maintenance. However, the existing capacitor condition monitoring methods suffer from either increased hardware cost or low estimation accuracy, being the challenges to be adopted in industry applications. New development in condition monitoring technology with software solutions without extra...

  7. Preserved intention maintenance and impaired execution of prospective memory responses in schizophrenia: evidence from an event-based prospective memory study

    Directory of Open Access Journals (Sweden)

    Gyula eDemeter

    2016-04-01

    Full Text Available Executive system dysfunction and impaired prospective memory (PM are widely documented in schizophrenia. However, it is not yet clarified which components of PM function are impaired in this disorder. Two plausible target components are the maintenance of delayed intentions and the execution of PM responses. Furthermore, it is debated whether the impaired performance on frequently used executive tasks is associated with deficit in PM functions. The aim of our study was twofold. First, we aimed to investigate the specific processes involved in event-based PM function, mainly focusing on difference between maintenance of intention and execution of PM responses. Second, we aimed to unfold the possible connections between executive functions, clinical symptoms, and PM performance. An event-based PM paradigm was applied with three main conditions: baseline (with no expectation of PM stimuli, and without PM stimuli, expectation condition (participants were told that PM stimuli might occur, though none actually did, and execution condition (participants were told that PM stimuli might occur, and PM stimuli did occur. This procedure allowed us to separately investigate performances associated with intention maintenance and execution of PM responses. We assessed working memory and set-shifting executive functions by memory span tasks and by the Wisconsin Card Sorting Test (WCST, respectively. Twenty patients diagnosed with schizophrenia and 20 healthy control subjects (matched according to age and education took part in the study. It was hypothesized that patients would manifest different levels of performance in the expectation and execution conditions of the PM task. Our results confirmed that the difference between baseline performance and performance in the execution condition (execution cost was significantly larger for participants diagnosed with schizophrenia in comparison with matched healthy control group. However, this difference was not

  8. Maintenance of Certification Part 4 Credit and recruitment for practice-based research.

    Science.gov (United States)

    Gorzkowski, Julie A; Klein, Jonathan D; Harris, Donna L; Kaseeska, Kristen R; Whitmore Shaefer, Regina M; Bocian, Alison B; Davis, James B; Gotlieb, Edward M; Wasserman, Richard C

    2014-10-01

    Competing priorities in pediatric practice have created challenges for practice-based research. To increase recruitment success, researchers must design studies that provide added value to participants. This study evaluates recruitment of pediatricians into a study, before and after the development and addition of a quality improvement (QI) curriculum approved for American Board of Pediatrics Maintenance of Certification (MOC) Part 4 Credit as an enrollment incentive. Researchers implemented multiple outreach methods to enroll pediatric practices over 28 months. Field note review revealed that many physicians declined enrollment, stating that they prioritized MOC Part 4 projects over research studies. A QI curriculum meeting standards for MOC Part 4 Credit was developed and added to the study protocol as an enrollment incentive. Enrollment rates and characteristics of practitioners enrolled pre- and post-MOC were compared. Pre-MOC enrollment contributed 48% of practices in 22 months; post-MOC enrollment contributed 49% of practices in 6 months. An average of 3.5 practices enrolled per month pre-MOC, compared with 13.1 per month post-MOC (P recruitment success and increased enrollment of pediatricians working in underserved areas. Including QI initiatives meeting MOC Part 4 criteria in practice-based research protocols may enhance participation and aid in recruiting diverse practice and patient populations. Copyright © 2014 by the American Academy of Pediatrics.

  9. Crack Growth-Based Predictive Methodology for the Maintenance of the Structural Integrity of Repaired and Nonrepaired Aging Engine Stationary Components

    National Research Council Canada - National Science Library

    Barron, Michael

    1999-01-01

    .... Specifically, the FAA's goal was to develop "Crack Growth-Based Predictive Methodologies for the Maintenance of the Structural Integrity of Repaired and Nonrepaired Aging Engine Stationary Components...

  10. APPLICATION OF ROUGH SET THEORY TO MAINTENANCE LEVEL DECISION-MAKING FOR AERO-ENGINE MODULES BASED ON INCREMENTAL KNOWLEDGE LEARNING

    Institute of Scientific and Technical Information of China (English)

    陆晓华; 左洪福; 蔡景

    2013-01-01

    The maintenance of an aero-engine usually includes three levels ,and the maintenance cost and period greatly differ depending on the different maintenance levels .To plan a reasonable maintenance budget program , airlines would like to predict the maintenance level of aero-engine before repairing in terms of performance parame-ters ,which can provide more economic benefits .The maintenance level decision rules are mined using the histori-cal maintenance data of a civil aero-engine based on the rough set theory ,and a variety of possible models of upda-ting rules produced by newly increased maintenance cases added to the historical maintenance case database are in-vestigated by the means of incremental machine learning .The continuously updated rules can provide reasonable guidance suggestions for engineers and decision support for planning a maintenance budget program before repai-ring .The results of an example show that the decision rules become more typical and robust ,and they are more accurate to predict the maintenance level of an aero-engine module as the maintenance data increase ,which illus-trates the feasibility of the represented method .

  11. Value maximizing maintenance policies under general repair

    International Nuclear Information System (INIS)

    Marais, Karen B.

    2013-01-01

    One class of maintenance optimization problems considers the notion of general repair maintenance policies where systems are repaired or replaced on failure. In each case the optimality is based on minimizing the total maintenance cost of the system. These cost-centric optimizations ignore the value dimension of maintenance and can lead to maintenance strategies that do not maximize system value. This paper applies these ideas to the general repair optimization problem using a semi-Markov decision process, discounted cash flow techniques, and dynamic programming to identify the value-optimal actions for any given time and system condition. The impact of several parameters on maintenance strategy, such as operating cost and revenue, system failure characteristics, repair and replacement costs, and the planning time horizon, is explored. This approach provides a quantitative basis on which to base maintenance strategy decisions that contribute to system value. These decisions are different from those suggested by traditional cost-based approaches. The results show (1) how the optimal action for a given time and condition changes as replacement and repair costs change, and identifies the point at which these costs become too high for profitable system operation; (2) that for shorter planning horizons it is better to repair, since there is no time to reap the benefits of increased operating profit and reliability; (3) how the value-optimal maintenance policy is affected by the system's failure characteristics, and hence whether it is worthwhile to invest in higher reliability; and (4) the impact of the repair level on the optimal maintenance policy. -- Highlights: •Provides a quantitative basis for maintenance strategy decisions that contribute to system value. •Shows how the optimal action for a given condition changes as replacement and repair costs change. •Shows how the optimal policy is affected by the system's failure characteristics. •Shows when it is

  12. Maintenance for the Millennium: Another Approach

    International Nuclear Information System (INIS)

    Sculthorpe, Barruy R.

    2002-01-01

    Nuclear units nationwide are struggling to increase plant reliability and availability while at the same time reduce their operating and maintenance costs. Some very costly investments have been made in programs such as Reliability Centered Maintenance [RCM]. Florida Power and Light's approach at the St. Lucie Nuclear Plant has taken a slightly different approach. Building on our knowledge of the RCM process and an already existing 'World Class' Predictive Maintenance Program, a 'Condition-Based' Maintenance Program that takes advantage of the RCM philosophy and our toolbox full of advanced and highly successful predictive maintenance technologies. These tools currently consist of vibration analysis, lubricant analysis (both physical property and wear metals analysis, thermographic analysis, motor current signature analysis, tribology and process parameter trending. All employed with the intent to evaluate a machines health. This machine health check allows the forecasting of future preventative maintenance [PM's] tasks and the revision of existing PM's to maximize machine performance and eliminate 'no-value-added' maintenance activities/costs. Within the last year, the Condition-Based Maintenance Program has produced a cost saving of approximately $1.5 million dollars. As the program matures, these cost savings will accumulate well into the millennium. (authors)

  13. Data Base Development of Automobile and Light Truck Maintenance : Volume I. Test and Appendixes A-D

    Science.gov (United States)

    1978-08-01

    The volume describes the development of the life cycle maintenance costs for 212 sales-leading 1970 through 1975 passenger cars and light trucks. These costs provide a data base for the Department of Transportation, which describes the costs for part...

  14. ON THE NECESSITY OF CHANGES IN THE STRATEGY OF UTILIZATION SHIP BOILER TECHNICAL CONDITION MAINTENANCE IN THE ASPECT OF LNG APPLIED AS FUEL

    Directory of Open Access Journals (Sweden)

    Andrzej ADAMKIEWICZ

    2017-01-01

    Full Text Available Heavy oils (HFO fuels used on ships play a part in degradation of technical condition of heat exchange surfaces of utiliza-tion boilers especially on the exhaust gas side. Presence of sulphur in these fuels is the main factor favouring degrada-tion. The upper limit for sulphur content in the fuel used outside the SECA areas equal to 3.5% is currently in force, at least until the year 2020 or 2025. The recommended by classification societies overhauls of utilization boilers are, there-fore characterized by a specially chosen strategy thanks to which it is possible to maintain their appropriate technical condition. The requirement to use fuels with low sulphur content (LSFO, which are significantly more expensive than MDO fuels, in the areas of controlled sulphur emissions also led to a further introduction of alternative fuels, such as methanol and above all liquefied natural gas (LNG, onto ships. That is especially valid for the ship owners whose vessels e.g. ferries sail mainly within SCECA This article analyses the consequences of the introduced fuel change on utilization boiler maintenance. A change in the technical condition maintenance strategy for utilization boilers has been suggested.

  15. CALiPER Retail Lamps Study RRL3.2 Lumen and Chromaticity Maintenance of LED A lamps Operated in Steady-State Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Royer, Michael P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCullough, Jeffrey J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tucker, Joseph C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    The lumen depreciation and color shift of 17 different A lamps (15 LED, 1 CFL, 1 halogen) was monitored in the automated long-term test apparatus (ALTA) for more than 7,500 hours. Ten samples of each lamp model were tested, with measurements recorded on a weekly basis. The lamps were operated continuously at an ambient temperature of 45°C (-1°C). Importantly, the steady-state test conditions were not optimized for inducing catastrophic failure for any of the lamp technologies—to which thermal cycling is a strong contributor— and are not typical of normal use patterns—which usually include off periods where the lamp cools down. Further, the test conditions differ from those used in standardized long-term test methods (i.e., IES LM-80, IES LM-84), so the results should not be directly compared. On the other hand, the test conditions are similar to those used by ENERGY STAR (when elevated temperature testing is called for). Likewise, the conditions and assumptions used by manufacturers to generated lifetime claims may vary; the CALiPER long-term data is informative, but cannot necessarily be used to discredit manufacturer claims. The test method used for this investigation should be interpreted as one more focused on the long-term effects of elevated temperature operation, at an ambient temperature that is not uncommon in luminaires. On average, the lumen maintenance of the LED lamps monitored in the ALTA was better than benchmark lamps, but there was considerable variation from lamp model to lamp model. While three lamp models had average lumen maintenance above 99% at the end of the study period, two products had average lumen maintenance below 65%, constituting a parametric failure. These two products, along with a third, also exhibited substantial color shift, another form of parametric failure. While none of the LED lamps exhibited catastrophic failure—and all of the benchmarks did—the early degradation of performance is concerning, especially with a

  16. Factors associated with interest in receiving prison-based methadone maintenance therapy in Malaysia.

    Science.gov (United States)

    Mukherjee, Trena I; Wickersham, Jeffrey A; Desai, Mayur M; Pillai, Veena; Kamarulzaman, Adeeba; Altice, Frederick L

    2016-07-01

    Methadone maintenance therapy (MMT) is crucial for HIV prevention and treatment in people who inject opioids. In Malaysia, a large proportion of the prison population is affected by both HIV and opioid use disorders. This study assessed individual preferences and factors associated with interest in receiving MMT among male prisoners meeting criteria for opioid dependence in Malaysia. A convenience sample of 96 HIV-positive and 104 HIV-negative incarcerated men who met pre-incarceration criteria for opioid dependence was interviewed using a structured questionnaire to examine participant characteristics and attitudes toward MMT. Factors associated with interest in prison-based MMT initiation were identified using logistic regression analysis. Among all participants, 85 (42.5%) were interested in receiving MMT within prison. Independent correlates of interest in prison-based MMT were being previously married (AOR=4.15, 95% CI: 1.15, 15.02), previously incarcerated (AOR=5.68, 95% CI: 1.54, 21.02), depression (AOR=3.66, 95% CI: 1.68, 7.98), daily heroin use in the 30days prior to incarceration (AOR=5.53, 95% CI: 1.65, 18.58), and more favorable attitudes toward MMT (AOR=19.82, 95% CI: 6.07, 64.74). Overall, interest in receiving prison-based MMT was low, and was associated with adverse social, mental health, and drug use consequences. Incarceration provides a unique opportunity to initiate MMT for those who need it, however, optimal scale-up efforts must be systemic and address modifiable factors like improving attitudes toward and motivation for MMT. Informed or shared decision-making tools may be useful in improving expectations and acceptability of MMT. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Laboratory equipment maintenance contracts.

    Science.gov (United States)

    Boudreau, D A; Scheer, W D; Catrou, P G

    1985-12-01

    The increasing level of technical sophistication and complexity found in clinical laboratory instrumentation today more than ever demands careful attention to maintenance service needs. The time-worn caution for careful definition of requirements for acquisition of a system should also carry over to acquisition of maintenance service. Guidelines are presented for specifications of terms and conditions for maintenance service from the perspective of the laboratorian in the automated clinical laboratory.

  18. Tiger: knowledge based gas turbine condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Trave-Massuyes, L. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Quevedo, J. [University of Catalonia, (Spain); Milne, R.; Nicol, Ch.

    1995-12-31

    Exxon petrochemical plant in Scotland requires continuous ethylene supply from offshore site in North Sea. The supply is achieved thanks to compressors driven by a 28 MW gas turbine, whose monitoring is of major importance. The TIGER fault diagnostic system is a knowledge base system containing a prediction model. (D.L.) 11 refs.

  19. Tiger: knowledge based gas turbine condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Trave-Massuyes, L [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Quevedo, J [University of Catalonia, (Spain); Milne, R; Nicol, Ch

    1996-12-31

    Exxon petrochemical plant in Scotland requires continuous ethylene supply from offshore site in North Sea. The supply is achieved thanks to compressors driven by a 28 MW gas turbine, whose monitoring is of major importance. The TIGER fault diagnostic system is a knowledge base system containing a prediction model. (D.L.) 11 refs.

  20. Predictive maintenance: A new approach in maintenance of nuclear power plants

    International Nuclear Information System (INIS)

    Benvenuto, F.; Ferrari, L.

    2005-01-01

    The maintenance services for a Nuclear Power Plant are in general aimed at reaching the following goals: - Increase component availability and consequently decrease intervention frequency; - Reduce unexpected costs from unexpected repairs; - Progressively decrease the time of each intervention; - Improve the spare parts supply efficiency; - Improve spare parts and consumable warehouse managing; - Decrease maintenance costs. Most of the currently used maintenance activities refer to run-to-failure or preventive approaches: - Run-to-failure or Corrective Maintenance means that work is only carried out when a component or system is faulty and unable to perform its critical function. Non critical components such as filters or components with spare may be maintained in this way; - Preventive or Scheduled Maintenance involves a regular pre-set schedule programme of maintenance work. Programme outlined by the manufacturer of the component in question based on the design life of the component and based on past experience by operation. One step further than Preventive Maintenance is represented by Predictive Maintenance. Whereas Preventive Maintenance bases its schedules on past performance data, a predictive system acquires condition data from the machine to be maintained whilst the machine is in operation. The information obtained from this analysis indicates the condition in real time, provides a diagnosis of wear and shows any trend towards critical conditions. Predictive maintenance mainly consists of the following interventions: - Lubricant analysis; - Collection / analysis of functional parameters, such as motor absorption, flow rate, pressure, temperature, noise, vibration of rotating equipment, thermal efficiency, etc; - Periodical test of lifting systems; - Other operations to acquire sensitive equipment parameters. Predictive Maintenance can reduce the accidental intervention and extend the components life, and, in the end, is increasing the global availability

  1. Road Edge of Pavement, Pavement Condition Ratings and Maintenance Designations per Street Centerline. Updated frequently by Public Works Streets Division, Published in 2006, 1:1200 (1in=100ft) scale, City of Asheville Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Road Edge of Pavement dataset current as of 2006. Pavement Condition Ratings and Maintenance Designations per Street Centerline. Updated frequently by Public Works...

  2. Employment-based abstinence reinforcement as a maintenance intervention for the treatment of cocaine dependence: post-intervention outcomes

    Science.gov (United States)

    DeFulio, Anthony; Silverman, Kenneth

    2011-01-01

    Aims Due to the chronicity of cocaine dependence, practical and effective maintenance interventions are needed to sustain long-term abstinence. We sought to assess the effects of long-term employment-based reinforcement of cocaine abstinence after discontinuation of the intervention. Design Participants who initiated sustained opiate and cocaine abstinence during a 6-month abstinence reinforcement and training program worked as data entry operators and were randomly assigned to a group that could work independent of drug use (Control, n = 24), or an abstinence-contingent employment (n = 27) group that was required to provide cocaine- and opiate-negative urine samples to work and maintain maximum rate of pay. Setting A nonprofit data entry business. Participants Unemployed welfare recipients who persistently used cocaine while in methadone treatment. Measurements Urine samples and self-reports were collected every six months for 30 months. Findings During the employment year, abstinence-contingent employment participants provided significantly more cocaine-negative samples than controls (82.7% and 54.2%; P = .01, OR = 4.61). During the follow-up year, the groups had similar rates of cocaine-negative samples (44.2% and 50.0%; P = .93), and HIV-risk behaviors. Participants’ social, employment, economic, and legal conditions were similar in the two groups across all phases of the study. Conclusions Employment-based reinforcement effectively maintains long-term cocaine abstinence, but many patients relapse to use when the abstinence contingency is discontinued, even after a year of abstinence-contingent employment. Relapse could be prevented in many patients by leaving employment-based abstinence reinforcement in place indefinitely, which could be facilitated by integrating it into typical workplaces. PMID:21226886

  3. Vision based condition assessment of structures

    International Nuclear Information System (INIS)

    Uhl, Tadeusz; Kohut, Piotr; Holak, Krzysztof; Krupinski, Krzysztof

    2011-01-01

    In this paper, a vision-based method for measuring a civil engineering construction's in-plane deflection curves is presented. The displacement field of the analyzed object which results from loads was computed by means of a digital image correlation coefficient. Image registration techniques were introduced to increase the flexibility of the method. The application of homography mapping enabled the deflection field to be computed from two images of the structure, acquired from two different points in space. An automatic shape filter and a corner detector were implemented to calculate the homography mapping between the two views. The developed methodology, created architecture and the capabilities of software tools, as well as experimental results obtained from tests made on a lab set-up and civil engineering constructions, are discussed.

  4. Vision based condition assessment of structures

    Energy Technology Data Exchange (ETDEWEB)

    Uhl, Tadeusz; Kohut, Piotr; Holak, Krzysztof; Krupinski, Krzysztof, E-mail: tuhl@agh.edu.pl, E-mail: pko@agh.edu.pl, E-mail: holak@agh.edu.pl, E-mail: krzysiek.krupinski@wp.pl [Department of Robotics and Mechatronics, AGH-University of Science and Technology, Al.Mickiewicza 30, 30-059 Cracow (Poland)

    2011-07-19

    In this paper, a vision-based method for measuring a civil engineering construction's in-plane deflection curves is presented. The displacement field of the analyzed object which results from loads was computed by means of a digital image correlation coefficient. Image registration techniques were introduced to increase the flexibility of the method. The application of homography mapping enabled the deflection field to be computed from two images of the structure, acquired from two different points in space. An automatic shape filter and a corner detector were implemented to calculate the homography mapping between the two views. The developed methodology, created architecture and the capabilities of software tools, as well as experimental results obtained from tests made on a lab set-up and civil engineering constructions, are discussed.

  5. Use of knowledge based systems for rational reliability analysis based inspection and maintenance planning for offshore structures

    International Nuclear Information System (INIS)

    Tang, M.X.; Dharmavasan, S.; Peers, S.M.C.

    1994-01-01

    The structural integrity of fixed offshore platforms is ensured by periodic inspections. In the past, decisions made as to when, where and how to inspect have been made by engineers using rules-of-thumb and general planning heuristics. It is now hoped that more rational inspection and maintenance scheduling may be carried out by applying recently developed techniques based on structural reliability methods. However, one of the problems associated with a theoretical approach is that it is not always possible to incorporate all the constraints that are present in a practical situation. These constraints modify the decisions made for analysis data input and the interpretation of the analysis results. Knowledge based systems provide a mean of encapsulating several different forms of information and knowledge within a computer system and hence can overcome this problem. In this paper, a prototype system being developed for integrating reliability based analysis with other constraints for inspection scheduling will be described. In addition, the scheduling model and the algorithms to carry out the scheduling will be explained. Furthermore, implementation details are also given

  6. e-Learning Content Design for Corrective Maintenance of Toshiba BMC 80.5 based on Knowledge Conversion using SECI Method: A Case Study in Aerospace Company

    Science.gov (United States)

    Permata Shabrina, Ayu; Pramuditya Soesanto, Rayinda; Kurniawati, Amelia; Teguh Kurniawan, Mochamad; Andrawina, Luciana

    2018-03-01

    Knowledge is a combination of experience, value, and information that is based on the intuition that allows an organization to evaluate and combine new information. In an organization, knowledge is not only attached to document but also in routine value creating activities, therefore knowledge is an important asset for the organization. X Corp is a company that focused on manufacturing aerospace components. In carrying out the production process, the company is supported by various machines, one of the machines is Toshiba BMC 80.5. The machine is used occasionally and therefore maintenance activity is needed, especially corrective maintenance. Corrective maintenance is done to make a breakdown machine back to work. Corrective maintenance is done by maintenance operator whose retirement year is close. The long term experience of the maintenance operator needs to be captured by the organization and shared across maintenance division. E-learning is one type of media that can support and assist knowledge sharing. This research purpose is to create the e-learning content for best practice of corrective maintenance activity for Toshiba BMC 80.5 by extracting the knowledge and experience from the operator based on knowledge conversion using SECI method. The knowledge source in this research is a maintenance supervisor and a senior maintenance engineer. From the evaluation of the e-learning content, it is known that the average test score of the respondents who use the e-learning increases from 77.5 to 87.5.

  7. A qualitative phenomenological study: Enhanced, risk-based FAA oversight on part 145 maintenance practices

    Science.gov (United States)

    Sheehan, Bryan G.

    The purpose of this qualitative phenomenological study was to examine the phenomenon of enhanced, risk-based Federal Aviation Administration (FAA) oversight of Part 145 repair stations that performed aircraft maintenance for Part 121 air carriers between 2007 and 2014 in Oklahoma. Specifically, this research was utilized to explore what operational changes have occurred in the domestic Part 145 repair station industry such as variations in management or hiring practices, training, recordkeeping and technical data, inventory and aircraft parts supply-chain logistics, equipment, and facilities. After interviewing 12 managers from Part 145 repair stations in Oklahoma, six major theme codes emerged from the data: quality of oversight before 2007, quality of oversight after 2007, advantages of oversight, disadvantages of oversight, status quo of oversight, and process improvement . Of those six major theme codes, 17 subthemes appeared from the data that were used to explain the phenomenon of enhanced oversight in the Part 145 repair station industry. Forty-two percent of the participants indicated a weak FAA oversight system that has hindered the continuous process improvement program in their repair stations. Some of them were financially burdened after hiring additional full-time quality assurance inspectors to specifically manage enhanced FAA oversight. Notwithstanding, the participants of the study indicated that the FAA must apply its surveillance on a more standardized and consistent basis. They want to see this standardization in how FAA inspectors interpret regulations and practice the same quality of oversight for all repair stations, particularly those that are repeat violators and fail to comply with federal aviation regulations. They believed that when the FAA enforces standardization on a consistent basis, repair stations can become more efficient and safer in the performance of their scope of work for the U.S. commercial air transportation industry.

  8. INCREASING THE AIRCRAFT AIRWORTHINESS MAINTENANCE EFICIENCY BASED ON THE PROJECT MANAGEMENT METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Alexander Abramovich Itskovich

    2017-01-01

    Full Text Available The interrelation between aircraft airworthiness maintenance process (AAMP and the process of project man- agement methodology application is demonstrated.A project portfolio can be formed based on the strategic objectives. The projects with the highest priority are car- ried out, including those which strive to improve the efficiency of AAMP. The proposed approach allows to find the priori- ties of specific projects realization, which are included in the airline project portfolio.The project aimed to improve the efficiency of the AAMP of AN-124-100 of "Volga-Dnepr Airlines" is presented as an example. The statistical data analysis of failures of AN-124-100 fleet has demonstrated that wing components most frequently fail, especially spoiler sections, which are subjected to honeycomb skin mass exfoliation and need to be modi- fied. One of the expected project results should be the К1000 reduction of the wing spoilers not less than for 40 % and, respectively, the plane in total - not less than for 4 %.The work is executed in full compliance with the standards of project management. The passport of the project is given, which contains all the necessary information about the project: its goals, outcomes, results, timelines, action plan, budget and participants. A special attention is paid to the risks of the project, their probability assessment and the actions for overcoming possible consequences. It is shown that the implementation of the project "Introduction of aircraft AN-124-100 spoilers technology modi- fication" allows to improve a number of production and technical efficiency indicators, with material, financial and organi- zational resources optimization.

  9. The use of probabilistic safety assessment (PSA) based maintenance indicators to increase the availability of safety related systems in nuclear power plants

    International Nuclear Information System (INIS)

    Kirchsteiger, C.

    1991-04-01

    This work describes the theoretical development of a Probabilistic Safety Assessment (PSA) based Performance Indicator (PI) model for a comprehensive Maintenance Efficiency Analysis (MEA) and its practical application to past operational history data of a certain nuclear power plant. Plant specific equipment history and maintenance work on data have been collected and analysed using various advanced statistical procedures (nonparametric methods, multivariate analysis in order to be able to estimate safety system related equipment and maintenance process trends. The main results of such a MEA case study are the trends in the (in)effectiveness of the performance of a selected safety system and its dominant components as well as the detection of the dominant maintenance related causes of its bad (good) equipment performance. Finally, the therefrom gained results are used to propose a new set of safety system-based and maintenance-related performance indicators, including suggestions for a corresponding plant specific maintenance data collection system. (author)

  10. The use of probabilistic safety assessment based maintenance indicators to increase the availability of safety related systems in nuclear power plants

    International Nuclear Information System (INIS)

    Kirchsteiger, C.

    1991-04-01

    This work describes the theoretical development of a Probabilistic Safety Assessment (PSA) based Performance Indicator (PI) model for a comprehensive Maintenance Efficiency Analysis (MEA) and its practical application to past operational history data of a certain Nuclear Power Plant. Plant specific equipment history and maintenance work order data have been collected and analysed using various advanced statistical procedures (nonparametric methods, multivariate analysis) in order to be able to estimate safety system related equipment and maintenance process trends. The main results of such a MEA case study are the trends in the (in)effectiveness of the performance of a selected safety system and its dominant maintenance related causes of its bad (good) equipment performance. Finally, the therefrom gained results are used to propose a new set of safety system based and maintenance related Performance Indicators, including suggestions for a corresponding plant specific maintenance data collection system. (author)

  11. Effectiveness of the GAEC cross compliance standard Maintenance of olive groves in good vegetative condition in avoiding the deterioration of habitats and land abandonment

    Directory of Open Access Journals (Sweden)

    Elena Santilli

    2011-08-01

    Full Text Available The last CAP reform (Council Regulation (EC n. 1782/2003, coincided with the mandatory obligations of the principles of cross compliance, under which all compensatory payments given in the context of the former reform packages were replaced by a Single Payment Scheme (SPS, bound to fulfillment of certain requirements and minimum standards regarding the environment and animal welfare, as well as maintaining the land in good agricultural and environmental conditions. For the olive sector, where potential risks are mainly associated to the abandonment of groves in marginal areas with consequent negative environmental impact, it has been specifically established the standard 4.3 of the Good Agricultural and Environmental Conditions (GAEC which concerns the Maintenance of olive groves and vines in good vegetative conditions. This GAEC standard was formulated to ensure a minimum level of land maintenance and to avoid the deterioration of habitats. To achieve these objectives it should be considered that a good vegetative development is strictly related to the care of the soil in which the plants grow. Erosion, organic matter and soil structure decay are the most commonly identified impacts for olive orchards, 30% of which are localized in areas with difficult orographic conditions. In this sense, proper hydraulic and mechanical techniques, cover cropping, green manuring and timely pruning turns, are essential to minimize losses due to soil erosion, to limit the leaching of nutrients and to maintain the plant productivity. Furthermore, grinded pruning residues should be spread in situ and weeds, watersprouts and suckers should be periodically cut off in order to increase the atmospheric CO2 sequestration and soil organic matter (OM and to prevent wildfires risk and nutrients competition. The application of the standard 4.3 requires further investigations, because, while numerous studies have shown that pruning is essential for the production, there are

  12. Knowledge engineering thinking of maintenance

    International Nuclear Information System (INIS)

    2007-01-01

    Maintenance optimization problem could not always settled mathematically and was obliged to use quasi-optimum solution with omitting non-formulated limiting condition or neglecting part of optimization object. In such a case knowledge engineering thinking was encouraged. Maintenance of complicated plant and artificial system should be considered from artificial object (equipment/facility hardware and system), technical information and knowledge base, and organizational and human aspect or society and institution. Comprehensive management system in organization and society was necessary not only for assuring integrity of equipment but also for attaining higher performance, reliability and economics of system. For better judgment it was important to share mechanism to make use of more information with organization or whole society. It was required to create database and data mining for knowledge base management system of maintenance. Maintenance was called 'last fortress' to assure quality such as reliability and safety of required function of equipment. Strategic approach to develop maintenance technology under cooperation was considered. Life extension R and D road map was launched in 2005. (T. Tanaka)

  13. Condition Based Maintenance Technology Impacts Study for the Military Land Environment

    Science.gov (United States)

    2014-08-01

    approach for quantifying retrospective energy savings, clean energy advances, and market effects. US Department of Energy, July 2007, 12 pages. 16...documentation costs, research costs (TRAs, BOPs, market surveys, etc.) Reduced administrative costs associated with delays in implementation Suppliers, ADF... armoured vehicles became combat ineffective after arriving in combat theatre, due to the rough terrain and the environment (temperature related). Many

  14. Condition Based Maintenance Technology Impact Study: Assessment Methods, Study Design and Interim Results

    Science.gov (United States)

    2014-07-01

    vibrations, dust, dirt, impact) and psychological parameters (operational tempo, level of threat, etc.) under which the technology will be...information through published references and via validation by SMEs. Further coding of both inputs and outputs on the map (using colours , shapes, and

  15. Predictive Condition-Based Maintenance for Vertical Lift Vehicles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has invested significant effort in the past decade in developing and maturing technologies that enable efficient and effective use of Next-generation (NextGen)...

  16. A Methodical Development of Measures of Effectiveness for a Condition-Based Maintenance Management System

    Science.gov (United States)

    2014-06-01

    Metal products 10 11.5% Manufacturing- Food , beverages , tobacco 7 8.0% Utilities-Electricity Generation 7 8.0% Manufacturing-Petroleum refining...drivers “Critical success factors that determine whether business and marketing objectives are achieved” (SensaCom n.d.). power user A user who...responses were sought to the survey, and 87 valid responses were received from a wide range of individuals working across a variety of industries . The

  17. Abrasive wear based predictive maintenance for systems operating in sandy conditions

    NARCIS (Netherlands)

    Woldman, M.; Tinga, T.; Heide, E. van der; Masen, M.A.

    2015-01-01

    Machines operating in sandy environments are damaged by the abrasive action of sand particles that enter the machine and become entrapped between components and contacting surfaces. In the case of the military services the combination of a sandy environment and the wide range of tasks to be

  18. Modeling of Engine Parameters for Condition-Based Maintenance of the MTU Series 2000 Diesel Engine

    Science.gov (United States)

    2016-09-01

    particles in the analysis of engine oil samples (Jiang and Yan 2008). Lee monitors the exhaust gas temperature of the diesel engine for a roll-on...roll-off-passenger commercial vessel (Lee 2013). Jardine, Lin and Banjevic note other monitoring parameters, such as acoustic, moisture , humidity...expressed in terms of a constant y- intercept , , a disturbance, , an independent variable, , their past, −

  19. Health Monitoring for Condition-Based Maintenance of a HMMWV using an Instrumented Diagnostic Cleat

    Science.gov (United States)

    2008-10-15

    identify faults in the bearings, shaft , etc. In wheeled ground vehicles, loading varies significantly as mentioned above. If loads acting on the...vehicle could be fully measured or controlled in terms of the terrain input motions and/or spindle forces/moments, fault identification in wheeled...diagnostic results. - Vehicle speed traversing the cleat can be controlled. - Configuration of cleats can be designed to develop specific tests for

  20. Improving Legacy Aircraft Systems Through Condition-Based Maintenance: An H-60 Case Study

    Science.gov (United States)

    2014-09-01

    level functions. These decompositions are equivalent to a detailed design effort in systems engineering. NAMPSOPs have a common architectural structure...Assembly Power Available Spindle Cables No.1 Engine Load Demand Spindle Control Cables Engine Pneumatic Starters Auxiliary Power Unit IRCM FLIR Mission...Analysis Fuel System Main Rotor Head Main Module Main Gear Box Radiator Engine Output Shaft Auxiliary Power Unit Flight Control Cables Tail Landing

  1. Perceived benefits and barriers to exercise among persons with physical disabilities or chronic health conditions within action or maintenance stages of exercise.

    Science.gov (United States)

    Malone, Laurie A; Barfield, J P; Brasher, Joel D

    2012-10-01

    Information regarding factors that affect the initial step to exercise behavior change among persons with physical disabilities or chronic health conditions is available in the literature but much less is known regarding perceived benefits and barriers to exercise among those who are regularly active. The purpose of this study was to examine the perceived benefits and barriers to exercise among persons with physical disabilities or chronic health conditions within action or maintenance stages of exercise. Participants (n = 152) completed the Exercise Benefits and Barriers Scale (EBBS). For data analyses, disabilities and health conditions were grouped as neuromuscular, orthopedic, cardiovascular/pulmonary, or multiple conditions. Multivariate analysis of variance (MANOVA) was conducted to determine if mean differences on EBBS benefits and barriers scores existed among disability types, between sexes, among age groups, and between physical activity levels. Sum scores were computed to determine the strongest benefit and barrier responses. No significant mean differences in EBBS scores were found between disability types, sexes, age groups, or physical activity levels (p > 0.05). Strongest benefit responses varied by group. Strongest barrier responses were the same for all demographic groups: "Exercise tires me," "Exercise is hard work for me," and "I am fatigued by exercise." EBBS scores were similar across disability/health condition, sex, age, and physical activity level. Primary benefits reported were in the areas of improved physical performance and psychological outlook whereas the primary barriers were in the area of physical exertion. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. For whom does it work? moderators of outcome on the effect of a transdiagnostic internet-based maintenance treatment after inpatient psychotherapy: randomized controlled trial.

    Science.gov (United States)

    Ebert, David Daniel; Gollwitzer, Mario; Riper, Heleen; Cuijpers, Pim; Baumeister, Harald; Berking, Matthias

    2013-10-10

    Recent studies provide evidence for the effectiveness of Internet-based maintenance treatments for mental disorders. However, it is still unclear which participants might or might not profit from this particular kind of treatment delivery. The study aimed to identify moderators of treatment outcome in a transdiagnostic Internet-based maintenance treatment (TIMT) offered to patients after inpatient psychotherapy for mental disorders in routine care. Using data from a randomized controlled trial (N=400) designed to test the effectiveness of TIMT, we performed secondary analyses to identify factors moderating the effects of TIMT (intervention) when compared with those of a treatment-as-usual control condition. TIMT involved an online self-management module, asynchronous patient-therapist communication, a peer support group, and online-based progress monitoring. Participants in the control condition had unstructured access to outpatient psychotherapy, standardized outpatient face-to-face continuation treatment, and psychotropic management. Self-reports of psychopathological symptoms and potential moderators were assessed at the start of inpatient treatment (T1), at discharge from inpatient treatment/start of TIMT (T2), and at 3-month (T3) and 12-month follow-up (T4). Education level, positive outcome expectations, and diagnoses significantly moderated intervention versus control differences regarding changes in outcomes between T2 and T3. Only education level moderated change differences between T2 and T4. The effectiveness of the intervention (vs control) was more pronounced among participants with a low (vs high) education level (T2-T3: B=-0.32, SE 0.16, P=.049; T2-T4: B=-0.42, SE 0.21, P=.049), participants with high (vs low) positive outcome expectations (T2-T3: B=-0.12, SE 0.05, P=.02) and participants with anxiety disorder (vs mood disorder) (T2-T3: B=-0.43, SE 0.21, P=.04). Simple slope analyses revealed that despite some subgroups benefiting less from the

  3. JRR-3 maintenance program utilizing accumulated maintenance data

    International Nuclear Information System (INIS)

    Izumo, Hironobu; Kato, Tomoaki; Kinase, Masami; Torii, Yoshiya; Murayama, Yoji

    2007-07-01

    JRR-3(Japan Research Reactor No.3) has been operated for more than 15 years after the modification, without significant troubles by carrying out maintenance such as the preventive maintenance (mainly time-based maintenance) for the safety-grade equipments and the breakdown maintenance for the non-safety-grade equipments. Unscheduled shutdowns causes by aged non-safety-grade equipments have been increasing, and the resources such as budgets have been decreasing year by year. In this situation, JRR-3 maintenance program was reviewed about safety, reliability and economic efficiency. This report offers the policy of the maintenance review and the future direction of maintenance programs. (author)

  4. Maintenance methods

    International Nuclear Information System (INIS)

    Sanchis, H.; Aucher, P.

    1990-01-01

    The maintenance method applied at the Hague is summarized. The method was developed in order to solve problems relating to: the different specialist fields, the need for homogeneity in the maintenance work, the equipment diversity, the increase of the materials used at the Hague's new facilities. The aim of the method is to create a knowhow formalism, to facilitate maintenance, to ensure the running of the operations and to improve the estimation of the maintenance cost. One of the method's difficulties is the demonstration of the profitability of the maintenance operations [fr

  5. Challenges for Risk-based Maintenance Planning for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nielsen, Jannie Jessen; Sørensen, John Dalsgaard

    2011-01-01

    This paper concerns the development of a probabilistic model for riskbased maintenance planning for offshore wind turbines. A prior damage model can be combined with data to give an updated estimate of the probability of failure. For indicators, an indicator model is needed, and this paper presents...... how Bayesian networks can be used to learn such a model when past data is available....

  6. Tailoring a Web-Based Weight Maintenance Intervention for Northern Plains American Indian Public University Students

    Science.gov (United States)

    Hemmingson, Kaitlyn; Lucchesi, Roxanne; Droke, Elizabeth; Kattelmann, Kendra K.

    2016-01-01

    Objective: High levels of obesity-related health disparities are common among US American Indian (AI) populations. AI public university students often face unique challenges that may contribute to weight gain and related consequences. Few weight maintenance interventions have been developed that meet the needs of AI public university students. The…

  7. An Approach to Folksonomy-Based Ontology Maintenance for Learning Environments

    Science.gov (United States)

    Gasevic, D.; Zouaq, Amal; Torniai, Carlo; Jovanovic, J.; Hatala, Marek

    2011-01-01

    Recent research in learning technologies has demonstrated many promising contributions from the use of ontologies and semantic web technologies for the development of advanced learning environments. In spite of those benefits, ontology development and maintenance remain the key research challenges to be solved before ontology-enhanced learning…

  8. An integrated model of statistical process control and maintenance based on the delayed monitoring

    International Nuclear Information System (INIS)

    Yin, Hui; Zhang, Guojun; Zhu, Haiping; Deng, Yuhao; He, Fei

    2015-01-01

    This paper develops an integrated model of statistical process control and maintenance decision. The proposal of delayed monitoring policy postpones the sampling process till a scheduled time and contributes to ten-scenarios of the production process, where equipment failure may occur besides quality shift. The equipment failure and the control chart alert trigger the corrective maintenance and the predictive maintenance, respectively. The occurrence probability, the cycle time and the cycle cost of each scenario are obtained by integral calculation; therefore, a mathematical model is established to minimize the expected cost by using the genetic algorithm. A Monte Carlo simulation experiment is conducted and compared with the integral calculation in order to ensure the analysis of the ten-scenario model. Another ordinary integrated model without delayed monitoring is also established as comparison. The results of a numerical example indicate satisfactory economic performance of the proposed model. Finally, a sensitivity analysis is performed to investigate the effect of model parameters. - Highlights: • We develop an integrated model of statistical process control and maintenance. • We propose delayed monitoring policy and derive an economic model with 10 scenarios. • We consider two deterioration mechanisms, quality shift and equipment failure. • The delayed monitoring policy will help reduce the expected cost

  9. Development of predictive models for estimating warfarin maintenance dose based on genetic and clinical factors.

    Science.gov (United States)

    Yang, Lu; Linder, Mark W

    2013-01-01

    In this chapter, we use calculation of estimated warfarin maintenance dosage as an example to illustrate how to develop a multiple linear regression model to quantify the relationship between several independent variables (e.g., patients' genotype information) and a dependent variable (e.g., measureable clinical outcome).

  10. Actual Condition of Paddy Field Levee Maintenance by Various Farm Households including Large-scale Farming in the Developed Land Renting Area

    Science.gov (United States)

    Sakata, Yasuyo

    The survey of interview, resource acquisition, photographic operation, and questionnaire were carried out in the “n” Community in the “y” District in Hakusan City in Ishikawa Prefecture to investigate the actual condition of paddy field levee maintenance in the area where land-renting market was proceeding, large-scale farming was dominant, and the problems of geographically scattered farm-land existed. In the study zone, 1) an agricultural production legal person rent-cultivated some of the paddy fields and maintained the levees, 2) another agricultural production legal person rent-cultivated some of the soy bean fields for crop changeover and land owners maintained the levees. The results indicated that sufficient maintenance was executed on the levees of the paddy fields cultivated by the agricultural production legal person, the soy bean fields for crop changeover, and the paddy fields cultivated by the land owners. Each reason is considered to be the managerial strategy, the economic incentive, the mutual monitoring and cross-regulatory mechanism, etc.

  11. Software evolution and maintenance

    CERN Document Server

    Tripathy, Priyadarshi

    2014-01-01

    Software Evolution and Maintenance: A Practitioner's Approach is an accessible textbook for students and professionals, which collates the advances in software development and provides the most current models and techniques in maintenance.Explains two maintenance standards: IEEE/EIA 1219 and ISO/IEC14764Discusses several commercial reverse and domain engineering toolkitsSlides for instructors are available onlineInformation is based on the IEEE SWEBOK (Software Engineering Body of Knowledge)

  12. A preventive maintenance model with a two-level inspection policy based on a three-stage failure process

    International Nuclear Information System (INIS)

    Wang, Wenbin; Zhao, Fei; Peng, Rui

    2014-01-01

    Inspection is always an important preventive maintenance (PM) activity and can have different depths and cover all or part of plant systems. This paper introduces a two-level inspection policy model for a single component plant system based on a three-stage failure process. Such a failure process divides the system′s life into three stages: good, minor defective and severe defective stages. The first level of inspection, the minor inspection, can only identify the minor defective stage with a certain probability, but can always reveal the severe defective stage. The major inspection can however identify both defective stages perfectly. Once the system is found to be in the minor defective stage, a shortened inspection interval is adopted. If however the system is found to be in the severe defective stage, we may delay the maintenance action if the time to the next planned PM window is less than a threshold level, but otherwise, replace immediately. This corresponds to the well adopted maintenance policy in practice such as periodic inspections with planned PMs. A numerical example is presented to demonstrate the proposed model by comparing with other models. - Highlights: • The system′s deterioration goes through a three-stage process, namely, normal, minor defective and severe defective. • Two levels of inspections are proposed, e.g., minor and major inspections. • Once the minor defective stage is found, instead of taking a maintenance action, a shortened inspection interval is recommended. • When the severe defective stage is found, we delay the maintenance according to the threshold to the next PM. • The decision variables are the inspection intervals and the threshold to PM

  13. Using the system maintenance datastore to characterize lifetime maintenance for PLiM

    International Nuclear Information System (INIS)

    Watson, P.; Dam, R.; Nickerson, J.

    2004-01-01

    A comprehensive Plant Life Management (PLiM) program involves evaluating a large amount of information. For any plant, there are numerous maintenance, surveillance and inspection programs for the important systems, structures and components. There is extensive industry experience on component failure modes, degradation mechanisms and recommended maintenance practices. This information forms the basis of the aging assessment work, through which improvements to these plant programs are identified. AECL has developed several tools to manage the quantities of information required in aging assessment studies, such as the SYSTMS (SYtematic approach for the development of STrategy for Maintenance and Surveillance) tool and the System Maintenance Datastore (SMD). The SMD has been developed to serve as a hub to a Systematic based Adaptive Maintenance Program (SAMP), by storing maintenance resource requirements for recommended maintenance tasks for use by the other processes in a SAMP. The SMD can be used to (a) quantify the savings or cost of optimising a maintenance program, (b) characterize and understand long term trends in condition-based maintenance due to component aging, (c) quantify the resource savings due to optimum timing of component replacement or general plant refurbishment, and (d) provide aging assessment cost information for input to plant asset evaluation. The SMD contains data for regular maintenance program tasks, plant condition assessment recommendations, and equipment refurbishment costs. A prototype SMD has been developed with data tables populated with information from operating CANDU stations. The SMD is now available to be used either with a SYSTMS evaluation or with a plant's database of maintenance tasks. (author)

  14. Seismic Analysis Code (SAC): Development, porting, and maintenance within a legacy code base

    Science.gov (United States)

    Savage, B.; Snoke, J. A.

    2017-12-01

    The Seismic Analysis Code (SAC) is the result of toil of many developers over almost a 40-year history. Initially a Fortran-based code, it has undergone major transitions in underlying bit size from 16 to 32, in the 1980s, and 32 to 64 in 2009; as well as a change in language from Fortran to C in the late 1990s. Maintenance of SAC, the program and its associated libraries, have tracked changes in hardware and operating systems including the advent of Linux in the early 1990, the emergence and demise of Sun/Solaris, variants of OSX processors (PowerPC and x86), and Windows (Cygwin). Traces of these systems are still visible in source code and associated comments. A major concern while improving and maintaining a routinely used, legacy code is a fear of introducing bugs or inadvertently removing favorite features of long-time users. Prior to 2004, SAC was maintained and distributed by LLNL (Lawrence Livermore National Lab). In that year, the license was transferred from LLNL to IRIS (Incorporated Research Institutions for Seismology), but the license is not open source. However, there have been thousands of downloads a year of the package, either source code or binaries for specific system. Starting in 2004, the co-authors have maintained the SAC package for IRIS. In our updates, we fixed bugs, incorporated newly introduced seismic analysis procedures (such as EVALRESP), added new, accessible features (plotting and parsing), and improved the documentation (now in HTML and PDF formats). Moreover, we have added modern software engineering practices to the development of SAC including use of recent source control systems, high-level tests, and scripted, virtualized environments for rapid testing and building. Finally, a "sac-help" listserv (administered by IRIS) was setup for SAC-related issues and is the primary avenue for users seeking advice and reporting bugs. Attempts are always made to respond to issues and bugs in a timely fashion. For the past thirty-plus years

  15. Framework for Maintenance Planning

    DEFF Research Database (Denmark)

    Soares, C. Guedes; Duarte, J. Caldeira; Garbatov, Y.

    2010-01-01

    the design and during the whole life span of operational use, within an integrated framework founded on risk and reliability based techniques. The document addresses designers, decision makers and professionals responsible for or involved in establishing maintenance plans. The purpose of this document......The present document presents a framework for maintenance planning. Maintenance plays a fundamental role in counteracting degradation effects, which are present in all infrastructure and industrial products. Therefore, maintenance planning is a very critical aspect to consider both during...... is to present maintenance as an integrated approach that needs to be planned, designed, engineered, and controlled by proper qualitative and quantitative techniques. This document outlines the basic premises for maintenance planning and provides the general philosophies that can be followed and points to a best...

  16. Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

    Science.gov (United States)

    Blazej, Ryszard; Jurdziak, Leszek

    2017-12-01

    In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

  17. On maintenance management of wind and nuclear power plants

    International Nuclear Information System (INIS)

    Nilsson, Julia

    2009-11-01

    Electrical production in Sweden today is mainly from nuclear and hydro power. However, there is large increase in renewable energy like wind power and the installed new capacity goals are large. Several electrical production sources are important for the sustainability of the energy system. Maintenance is an approach for keeping a system sustainable. The importance of structured maintenance for reliable electrical production systems triggers the development of qualitative and quantitative maintenance management methods. Examples of these methods are Reliability-Centered Maintenance (RCM) which is a structured qualitative approach that focuses on reliability when planning maintenance, and Reliability Centered Asset Management (RCAM) which is a development of RCM into a quantitative approach with the aim to relate preventive maintenance to total maintenance cost and system reliability. This thesis presents models, as applications of RCAM, based on the methods of Life Cycle Cost (LCC) and mathematical optimization, applied to wind and nuclear power plants. Both deterministic and stochastic approaches have been used and the proposed models are based on the Total Cost model, which summarizes costs for maintenance and production loss, and the Aircraft model, which is an opportunistic maintenance optimization model. Opportunistic maintenance is preventive maintenance performed at opportunities. The wind power applications in this study show on different ways to cover costs of condition monitoring systems (CMS) and further on economic benefits of these when uncertainties of times to failure are included in the model. The nuclear power applications show on that the optimization model is dependent on the discount rate and that a high discount rate gives more motivation for opportunistic replacements. When put into a stochastic framework and compared to other maintenance strategies it is shown that an extended opportunistic maintenance optimization model has a good overall

  18. Evaluation of cable aging degradation based on plant operating condition

    International Nuclear Information System (INIS)

    Kim, Jong-Seog

    2005-01-01

    Extending the lifetime of nuclear power plant [(hereafter referred simply as ''NPP'')] is one of the most important concerns in the world nuclear industry. Cables are one of the long live items which have not been considered to be replaced during the design life of NPP. To extend the cable life beyond the design life, we need to prove that the design life is too conservative compared with the actual aging. Condition monitoring is one of the useful ways for evaluating the aging condition of cable. In order to simulate the natural aging in nuclear power plant, a study on accelerated aging needs to be conducted first. In this paper, evaluations of mechanical aging degradation for cable jacket were performed after accelerated aging under the continuous heating and intermittent heating. Contrary to general expectation, the intermittent heating to cable jacket showed low aging degradation, 50% break-elongation and 60% indenter modulus, compared with continuous heating. With the plant maintenance period of 1 month after every 12 or 18 months operation, we can easily deduce that the life time of cable jacket can be extended much longer than estimated through the general EQ (Environmental Qualification) test, which adopts continuous accelerated aging for determining cable life. Therefore, a systematic approach which considers the actual environment condition of nuclear power plant is required for determining the life of cables. (author)

  19. A reliability-based maintenance technicians' workloads optimisation model with stochastic consideration

    Science.gov (United States)

    Ighravwe, D. E.; Oke, S. A.; Adebiyi, K. A.

    2016-06-01

    The growing interest in technicians' workloads research is probably associated with the recent surge in competition. This was prompted by unprecedented technological development that triggers changes in customer tastes and preferences for industrial goods. In a quest for business improvement, this worldwide intense competition in industries has stimulated theories and practical frameworks that seek to optimise performance in workplaces. In line with this drive, the present paper proposes an optimisation model which considers technicians' reliability that complements factory information obtained. The information used emerged from technicians' productivity and earned-values using the concept of multi-objective modelling approach. Since technicians are expected to carry out routine and stochastic maintenance work, we consider these workloads as constraints. The influence of training, fatigue and experiential knowledge of technicians on workload management was considered. These workloads were combined with maintenance policy in optimising reliability, productivity and earned-values using the goal programming approach. Practical datasets were utilised in studying the applicability of the proposed model in practice. It was observed that our model was able to generate information that practicing maintenance engineers can apply in making more informed decisions on technicians' management.

  20. COMPARISON OF NON-COLIFORM BACTERIA IN BALI CATTLE FAECES BASED ON LEVEL OF MATURITY AND MAINTENANCE PATTERN

    Directory of Open Access Journals (Sweden)

    Kadek Andre Sulaksana

    2017-08-01

    Full Text Available This study aim was to determine the effect of maintenance type and maturity level of bali cattle to the total of non coliform bacteria in bali cattle. A total of 24 samples of bali cattle’s feces were used. This study was a Factorial 2 x 3 of group-randomised design, contained of two type maintenance (TPA Suwung and Sobangan and three levels of cattle maturity (calves, heifers, and adult. The groups were based on time sampling. The data then analyzed using Analysis of Variance Test and continued by using Least Significant Different test. The results showed that the amount of non-coliform bacteria in adult bali cattle feces were higher then heifers and calves. Total of non coliform bacteria in bali cattle in  landfill was higher then the cattle that reared in captivity in Bali Cattle Breeding Center, the Sobangan village of Mengwi Badung regency.

  1. PREVENTIVE MAINTENANCE. HONEYWELL PLANNING GUIDE.

    Science.gov (United States)

    Honeywell, Inc., Minneapolis, Minn.

    THIS HONEYWELL PAMPHLET DISCUSSES SOME ASPECTS OF PREVENTIVE MAINTENANCE OF AUTOMATIC CONTROLS, HEATING, VENTILATING, AND AIR CONDITIONING, AND COMPARES IN-PLANT WITH CONTRACT SERVICE, CONCLUDING THAT CONTRACT SERVICE IS PREFERABLE AND DESCRIBING A NUMBER OF MAINTENANCE PLANS WHICH THEY FURNISH. PREVENTIVE MAINTENANCE PROVIDES--(1) MORE EFFICIENT…

  2. Comparison of Content on the American Board of Internal Medicine Maintenance of Certification Examination With Conditions Seen in Practice by General Internists.

    Science.gov (United States)

    Gray, Bradley; Vandergrift, Jonathan; Lipner, Rebecca S; Green, Marianne M

    2017-06-13

    Success on the internal medicine (IM) examination is a central requirement of the American Board of Internal Medicine's (ABIM's) Maintenance of Certification program (MOC). Therefore, it is important to understand the degree to which this examination reflects conditions seen in practice, one dimension of content validity, which focuses on the match between content in the discipline and the topics on the examination questions. To assess whether the frequency of questions on IM-MOC examinations were concordant with the frequency of conditions seen in practice. The 2010-2013 IM-MOC examinations were used to calculate the percentage of questions for 186 medical condition categories from the examination blueprint, which balances examination content by considering importance and frequency of conditions seen in practice. Nationally representative estimates of conditions seen in practice by general internists were estimated from the primary diagnosis for 13 832 office visits (2010-2013 National Ambulatory Medical Care Surveys) and 108 472 hospital stays (2010 National Hospital Discharge Survey). Prevalence of conditions included on the IM-MOC examination questions. The outcome measure was the concordance between the percentages of IM-MOC examination questions and the percentages of conditions seen in practice during either office visits or hospital stays for each of 186 condition categories (eg, diabetes mellitus, ischemic heart disease, liver disease). The concordance thresholds were 0.5 SD of the weighted mean percentages of the applicable 186 conditions seen in practice (0.74% for office visits; 0.51% for hospital stays). If the absolute differences between the percentages of examination questions and the percentages of office visit conditions or hospital stay conditions seen were less than the applicable concordance threshold, then the condition category was judged to be concordant. During the 2010-2013 IM-MOC examination periods, 3600 questions (180 questions per

  3. Long-term maintenance of reducing conditions in a spent nuclear fuel repository. A re-examination of critical factors

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, M. [Gascoyne GeoProjects Inc, Pinawa, MB (Canada)

    1999-04-01

    Penetration of oxidising groundwaters to depths of 500 m in a permeable bedrock, over a glacial/interglacial cycle, may compromise the stability of a spent nuclear fuel repository and cause the release and migration towards the surface of actinides and associated fission products. This report examines the potential for the penetration of oxygen (O{sub 2}) to depths of 500 m in a fractured crystalline rock environment, typical of the Fennoscandian Shield. Previous studies performed for the Swedish program of nuclear waste disposal (principally the SITE-94 safety assessment) have indicated that O{sub 2} might reach repository depths during a deglaciation when melt-water from the base of an ice sheet could enter the bedrock, driven by strong hydraulic gradients. This report re-examines aspects of this scenario and finds that: 1. The capacity of flow-path minerals to scavenge O{sub 2} from recharging groundwater may be lower than expected due to a previously unrecognised depletion of Fe(II)-bearing minerals in the active flow-paths in a fractured crystalline rock. 2. Assumptions in the SITE-94 assessment, such as the use of a continental-scale flow model, the lack of structural controls on groundwater flow, a preferred horizontal permeability, and the use of permeabilities to depths of 10 km that are up to two orders of magnitude greater than comparable environments, are disproportionately simplistic and represent an extremely conservative case. 3. Assumptions of a thin, discontinuous permafrost, a warm-based ice sheet, and high-O{sub 2} content melt-water at the repository site are unrealistic and overly conservative. A more realistic scenario, which includes a greater influence of permafrost, a cold based ice sheet, lower bedrock permeabilities and a more-limited, regional-scale flow path, is recommended as being more appropriate for use in the safety assessment. Under this revised scenario, it is believed that O{sub 2} will not penetrate to repository depths over

  4. Long-term maintenance of reducing conditions in a spent nuclear fuel repository. A re-examination of critical factors

    International Nuclear Information System (INIS)

    Gascoyne, M.

    1999-04-01

    Penetration of oxidising groundwaters to depths of 500 m in a permeable bedrock, over a glacial/interglacial cycle, may compromise the stability of a spent nuclear fuel repository and cause the release and migration towards the surface of actinides and associated fission products. This report examines the potential for the penetration of oxygen (O 2 ) to depths of 500 m in a fractured crystalline rock environment, typical of the Fennoscandian Shield. Previous studies performed for the Swedish program of nuclear waste disposal (principally the SITE-94 safety assessment) have indicated that O 2 might reach repository depths during a deglaciation when melt-water from the base of an ice sheet could enter the bedrock, driven by strong hydraulic gradients. This report re-examines aspects of this scenario and finds that: 1. The capacity of flow-path minerals to scavenge O 2 from recharging groundwater may be lower than expected due to a previously unrecognised depletion of Fe(II)-bearing minerals in the active flow-paths in a fractured crystalline rock. 2. Assumptions in the SITE-94 assessment, such as the use of a continental-scale flow model, the lack of structural controls on groundwater flow, a preferred horizontal permeability, and the use of permeabilities to depths of 10 km that are up to two orders of magnitude greater than comparable environments, are disproportionately simplistic and represent an extremely conservative case. 3. Assumptions of a thin, discontinuous permafrost, a warm-based ice sheet, and high-O 2 content melt-water at the repository site are unrealistic and overly conservative. A more realistic scenario, which includes a greater influence of permafrost, a cold based ice sheet, lower bedrock permeabilities and a more-limited, regional-scale flow path, is recommended as being more appropriate for use in the safety assessment. Under this revised scenario, it is believed that O 2 will not penetrate to repository depths over the next 100,000 years

  5. An experimental maintenance management system.

    Science.gov (United States)

    1979-01-01

    The purpose of this study was to evaluate Virginia's maintenance management system and to recommend modifications directed at improving it. The study revealed that (1) the current system of allocating maintenance monies is based upon centerline milea...

  6. The design and use of proficiency based BWR reactor maintenance and refuelling training mockups

    International Nuclear Information System (INIS)

    Ford, G.J.

    1996-01-01

    The purpose of this paper is to describe the ABB experience with the design and use of boiling water reactor training facilities. The training programs were developed and implemented in cooperation with the nuclear utilities. ABB operates two facilities, the ABB ATOM Light Water Reactor Service Center located in Vasteras, Sweden, and the ABB Combustion Engineering Nuclear Operations BWR Training Center located in Chattanooga, Tennessee, USA. The focus of the training centers are reactor maintenance and refueling activities plus the capability to develop and qualify tools, procedures and repair techniques

  7. Preventative Maintenance.

    Science.gov (United States)

    Migliorino, James

    Boards of education must be convinced that spending money up front for preventive maintenance will, in the long run, save districts' tax dollars. A good program of preventive maintenance can minimize disruption of service; reduce repair costs, energy consumption, and overtime; improve labor productivity and system equipment reliability; handle…

  8. Condition-dependence, pleiotropy and the handicap principle of sexual selection in melanin-based colouration.

    Science.gov (United States)

    Roulin, Alexandre

    2016-05-01

    The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.

  9. Simulation-based man-machine interface evaluation for plant maintenance facilities

    International Nuclear Information System (INIS)

    Nakagawa, Takashi; Kitamura, Masashi; Nakatani, Yoshio; Umeda, Yoshikazu

    1998-01-01

    Although a lot of human errors has occurred in the maintenance of power plants, systematic approaches to the reduction of human error are not sufficient compared with those applied to operations. The authors propose a new method of evaluating and analyzing human interface design from the viewpoint of human error reduction, and have implemented the method on the DIAS system. This system consists of maintenance personnel and equipment interface simulators, and it generates a dynamic interaction between humans and the working environment. The DIAS system can calculate the human error rate and their weighted calculations according to dangerousness, the influence on the equipment, and the influence on the plant of each task by THERP, and can carry out the dynamic analysis of the panel selection error index if there is similar equipment in the neighborhood, the working time, the distance of movement, and the distance of eye movement. The authors applied this system to evaluate the interface design of actual Transformer Protection Relay Panels and their layout in a room in a nuclear power plant. Our customer accepted our evaluation and proposals modifying the panel design. (author)

  10. Selection of optimum maintenance strategies based on a fuzzy analytic hierarchy process

    Directory of Open Access Journals (Sweden)

    Aida Azizi

    2014-05-01

    Full Text Available This paper presents an empirical investigation to rank different factors influencing on maintenance strategies on Iranian oil terminals’ company. The study determines four main factors, production quality, reliability, cost and safety. Using fuzzy analytical process, the study determines various factors associated with each main factor and ranks them by performing pair-wise comparisons. The results indicate that reliability ranks first (0.255, followed by production quality (0.252, cost (0.25 and safety (0.244. In terms of reliability, the best utilization of resources is number one priority followed by increase access to maintenance tools, reduction in production interruption are among the most important issues. In terms of production quality, reduction in system failure as well as reworks is the most important factors followed by customer satisfaction and defects. In terms of cost items, ease of access to accessories and consulting are important factors followed by necessary software, hardware and training programs. Finally, in terms of safety factors, external, internal and employee services are the most important issues, which are needed to be considered.

  11. A pharmacogenetics-based warfarin maintenance dosing algorithm from Northern Chinese patients.

    Directory of Open Access Journals (Sweden)

    Jinxing Chen

    Full Text Available Inconsistent associations with warfarin dose were observed in genetic variants except VKORC1 haplotype and CYP2C9*3 in Chinese people, and few studies on warfarin dose algorithm was performed in a large Chinese Han population lived in Northern China. Of 787 consenting patients with heart-valve replacements who were receiving long-term warfarin maintenance therapy, 20 related Single nucleotide polymorphisms were genotyped. Only VKORC1 and CYP2C9 SNPs were observed to be significantly associated with warfarin dose. In the derivation cohort (n = 551, warfarin dose variability was influenced, in decreasing order, by VKORC1 rs7294 (27.3%, CYP2C9*3(7.0%, body surface area(4.2%, age(2.7%, target INR(1.4%, CYP4F2 rs2108622 (0.7%, amiodarone use(0.6%, diabetes mellitus(0.6%, and digoxin use(0.5%, which account for 45.1% of the warfarin dose variability. In the validation cohort (n = 236, the actual maintenance dose was significantly correlated with predicted dose (r = 0.609, P<0.001. Our algorithm could improve the personalized management of warfarin use in Northern Chinese patients.

  12. A Pharmacogenetics-Based Warfarin Maintenance Dosing Algorithm from Northern Chinese Patients

    Science.gov (United States)

    Luo, Fang; Wang, Jin'e; Shi, Yi; Tan, Yu; Chen, Qianlong; Zhang, Yu; Hui, Rutai; Wang, Yibo

    2014-01-01

    Inconsistent associations with warfarin dose were observed in genetic variants except VKORC1 haplotype and CYP2C9*3 in Chinese people, and few studies on warfarin dose algorithm was performed in a large Chinese Han population lived in Northern China. Of 787 consenting patients with heart-valve replacements who were receiving long-term warfarin maintenance therapy, 20 related Single nucleotide polymorphisms were genotyped. Only VKORC1 and CYP2C9 SNPs were observed to be significantly associated with warfarin dose. In the derivation cohort (n = 551), warfarin dose variability was influenced, in decreasing order, by VKORC1 rs7294 (27.3%), CYP2C9*3(7.0%), body surface area(4.2%), age(2.7%), target INR(1.4%), CYP4F2 rs2108622 (0.7%), amiodarone use(0.6%), diabetes mellitus(0.6%), and digoxin use(0.5%), which account for 45.1% of the warfarin dose variability. In the validation cohort (n = 236), the actual maintenance dose was significantly correlated with predicted dose (r = 0.609, Pwarfarin use in Northern Chinese patients. PMID:25126975

  13. Excellence through maintenance mastering

    International Nuclear Information System (INIS)

    Lamarche, M.; Guillot, M.; Monier, M.

    1987-01-01

    To improve the overall availability factor of nuclear power plants you have to cut either the forced outage role and the planned outage time or you need to reduce simultaneously the failures and the efforts devoted to avoiding them. Among other results, this goal leads to a decrease in the number of real or anticipated problems. Electricite de France policy, in this matter, is to focus on decreasing the compoents' maintenance needs through a comprehensive modification program, targeted to eliminating the weak points as revealed by the operation. Thereby one may reach, for simple equipment, a nearly maintenance-free condition in which the only maintenance needed is surveillance, which provides assurance that everything is operating properly. A good example of this type of equipment is the family of static components, drums, and pipes whose corrective maintenance is almost nil when their initial condition is good

  14. Catalog of 199 register-based definitions of chronic conditions

    DEFF Research Database (Denmark)

    Hvidberg, Michael F; Johnsen, Søren P; Glümer, Charlotte

    2016-01-01

    INTRODUCTION: The aim of the current study was to present and discuss a broad range of register-based definitions of chronic conditions for use in register research, as well as the challenges and pitfalls when defining chronic conditions by the use of registers. MATERIALS AND METHODS: The definit......INTRODUCTION: The aim of the current study was to present and discuss a broad range of register-based definitions of chronic conditions for use in register research, as well as the challenges and pitfalls when defining chronic conditions by the use of registers. MATERIALS AND METHODS......: The definitions were defined based on information from nationwide Danish public healthcare registers. Medical and epidemiological specialists identified and grouped relevant diagnosis codes that covered chronic conditions, using the International Classification System version 10 (ICD-10). Where relevant...... definitions were proposed based on record linkage between multiple registers, including registers of prescribed drugs and use of general practitioners' services. CONCLUSIONS THIS STUDY PROVIDED A CATALOG OF REGISTER-BASED DEFINITIONS FOR CHRONIC CONDITIONS FOR USE IN HEALTHCARE PLANNING AND RESEARCH, WHICH IS...

  15. Two Innovative Steps for Training on Maintenance: 'VIRMAN' Spanish Project based on Virtual Reality 'STARMATE' European Project based on Augmented Reality

    International Nuclear Information System (INIS)

    Gonzalez Anez, Francisco

    2002-01-01

    This paper presents two development projects (STARMATE and VIRMAN) focused on supporting training on maintenance. Both projects aim at specifying, designing, developing, and demonstrating prototypes allowing computer guided maintenance of complex mechanical elements using Augmented and Virtual Reality techniques. VIRMAN is a Spanish development project. The objective is to create a computer tool for maintenance training course elaborations and training delivery based on 3D virtual reality models of complex components. The training delivery includes 3D record displays on maintenance procedures with all complementary information for intervention understanding. Users are requested to perform the maintenance intervention trying to follow up the procedure. Users can be evaluated about the level of knowledge achieved. Instructors can check the evaluation records left during the training sessions. VIRMAN is simple software supported by a regular computer and can be used in an Internet framework. STARMATE is a forward step in the area of virtual reality. STARMATE is a European Commission project in the frame of 'Information Societies Technologies'. A consortium of five companies and one research institute shares their expertise in this new technology. STARMATE provides two main functionalities (1) user assistance for achieving assembly/de-assembly and following maintenance procedures, and (2) workforce training. The project relies on Augmented Reality techniques, which is a growing area in Virtual Reality research. The idea of Augmented Reality is to combine a real scene, viewed by the user, with a virtual scene, generated by a computer, augmenting the reality with additional information. The user interface is see-through goggles, headphones, microphone and an optical tracking system. All these devices are integrated in a helmet connected with two regular computers. The user has his hands free for performing the maintenance intervention and he can navigate in the virtual

  16. Physical activity maintenance among Spanish-speaking Latinas in a randomized controlled trial of an Internet-based intervention.

    Science.gov (United States)

    Hartman, Sheri J; Dunsiger, Shira I; Bock, Beth C; Larsen, Britta A; Linke, Sarah; Pekmezi, Dori; Marquez, Becky; Gans, Kim M; Mendoza-Vasconez, Andrea S; Marcus, Bess H

    2017-06-01

    Spanish-speaking Latinas have some of the lowest rates of meeting physical activity guidelines in the U.S. and are at high risk for many related chronic diseases. The purpose of the current study was to examine the maintenance of a culturally and individually-tailored Internet-based physical activity intervention for Spanish-speaking Latinas. Inactive Latinas (N  =  205) were randomly assigned to a 6-month Tailored Physical Activity Internet Intervention or a Wellness Contact Control Internet Group, with a 6-month follow-up. Maintenance was measured by assessing group differences in minutes per week of self-reported and accelerometer measured moderate to vigorous physical activity (MVPA) at 12 months after baseline and changes in MVPA between the end of the active intervention (month 6) and the end of the study (month 12). Potential moderators of the intervention were also examined. Data were collected between 2011 and 2014, and were analyzed in 2015 at the University of California, San Diego. The Intervention Group engaged in significantly more minutes of MVPA per week than the Control Group at the end of the maintenance period for both self-reported (mean diff. = 30.68, SE = 11.27, p = .007) and accelerometer measured (mean diff. = 11.47, SE = 3.19, p = .01) MVPA. There were no significant between- or within-group changes in MVPA from month 6 to 12. Greater intervention effects were seen for those with lower BMI (BMI × intervention = -6.67, SE = 2.88, p = .02) and lower perceived places to walk to in their neighborhood (access × intervention = -43.25, SE = 19.07, p = .02), with a trend for less family support (social support × intervention = -3.49, SE = 2.05, p = .08). Acculturation, health literacy, and physical activity related psychosocial variables were not significant moderators of the intervention effect during the maintenance period. Findings from the current study support the efficacy of an Internet

  17. An integrated motivational interviewing and cognitive-behavioural intervention promoting physical activity maintenance for adults with chronic health conditions: A feasibility study.

    Science.gov (United States)

    Scott, Sarah E; Breckon, Jeff D; Copeland, Robert J

    2018-01-01

    Objectives Physical activity is recommended for managing chronic health conditions but is rarely maintained. This feasibility study aimed to evaluate the preliminary efficacy of a motivational interviewing and cognitive-behavioural intervention for long-term physical activity for adults with chronic health conditions. Methods Participants ( N = 37) with stable conditions (e.g. diabetes) were randomized into a three-month motivational interviewing and cognitive-behavioural group ( N = 20) or usual care ( N = 17) after completing a physical activity referral scheme. Participants completed physical activity (e.g. average steps per day and kilocalorie expenditure), psychological (e.g. self-efficacy) and epidemiological (e.g. body mass index) standardized measures at baseline, three- and six-month follow-up. Treatment fidelity and feasibility were assessed. Results Thirty-five participants completed the study (96% retention). The motivational interviewing and cognitive-behavioural group maintained kilocalorie expenditure at three ( p = 0.009) and six months ( p = 0.009). Exercise barrier self-efficacy ( p = 0.03), physical ( p = 0.02) and psychological ( p = 0.01) physical activity experiences were increased at three months only. No difference was found for average steps/day, social support, coping skills and epidemiological factors. Discussion This is the first study to demonstrate the feasibility and preliminary efficacy of motivational interviewing and cognitive-behavioural interventions for promoting physical activity maintenance in a clinical population. A large-scale trial with a longer follow-up (≥6 months) is warranted with treatment fidelity assessment.

  18. Evaluation of reliability of on-site A.C. power systems based on maintenance records

    International Nuclear Information System (INIS)

    Basso, G.; Pia, S.; Fusari, W.; Soressi, G.; Vaccari, G.

    1986-01-01

    To the end of ascertain in what extent the evaluation of reliability of emergency diesel generators (D.G.) can be improved by means of a deeper knowledge of their operating history a study has been carried-out on 21 D.G. sets: 4 D.G. of the Caorso nuclear plant (BWR, 870 MWe) and 17 D.G. in service at 6 steam-electric fossil-fuelled plants. The major points of interest resulting from this study are: 1) reliability assessments of A.C. on-site power Systems, made on the basis of outcomes of surveillance tests, may lead to results which overestimate the real performance. 2) the unreliability of a redundant System of stand-by components is determined in large extent by unavailabilities due to scheduled and unscheduled maintenance, latent failures, tests. (authors)

  19. Evaluation of reliability of on-site A.C. power systems based on maintenance records

    Energy Technology Data Exchange (ETDEWEB)

    Basso, G.; Pia, S. [ENEA/TERM/VAOEC, C.R.E. Casaccla via Anguillarese, 00100 Roma/Rome (Italy); Fusari, W. [ENEL, Rome (Italy); Soressi, G.; Vaccari, G. [ENEL, Centro di Ricerca Termica e Nucl., Via Rubattino, 54, 1-20134 Mllano/Milan (Italy)

    1986-02-15

    To the end of ascertain in what extent the evaluation of reliability of emergency diesel generators (D.G.) can be improved by means of a deeper knowledge of their operating history a study has been carried-out on 21 D.G. sets: 4 D.G. of the Caorso nuclear plant (BWR, 870 MWe) and 17 D.G. in service at 6 steam-electric fossil-fuelled plants. The major points of interest resulting from this study are: 1) reliability assessments of A.C. on-site power Systems, made on the basis of outcomes of surveillance tests, may lead to results which overestimate the real performance. 2) the unreliability of a redundant System of stand-by components is determined in large extent by unavailabilities due to scheduled and unscheduled maintenance, latent failures, tests. (authors)

  20. Study of maintenance skill-work based on PSFs and error category

    International Nuclear Information System (INIS)

    Nagata, Manabu; Yukimachi, Takeo; Hasegawa, Toshio

    2001-01-01

    In this investigation, the skill-types of skill-work are clarified according to the human error data on the maintenance works at nuclear power plants. At first, the causal PSFs of the errors are extracted from the data and some of the skill-types are characterized as results from factor analysis. Moreover, the skill-work model is reexamined on the basis of the contents of the human error data and the error category corresponding to the data. Furthermore, integrating the tendency of the causal PSFs and the actual error category concerning each skill-type, an extended skill-work model was developed with a flow-chart representation as a tentative stage of the investigation. (author)

  1. Tampering by office-based methadone maintenance patients with methadone take home privileges: a pilot study

    Directory of Open Access Journals (Sweden)

    Frank Nathan

    2007-10-01

    Full Text Available Abstract Methadone Maintenance Treatment (MMT is among the most widely studied treatments for opiate dependence with proven benefits for patients and society. When misused, however, methadone can also be lethal. The issue of methadone diversion is a major concern for all MMT programs. A potential source for such diversion is from those MMT patients who receive daily take home methadone doses. Using a reverse phase high performance liquid chromatography method, seven of the nine patients who were randomly selected to have all of their remaining methadone take home doses (within a 24 hour period analyzed, returned lower than expected quantities of methadone. This finding suggests the possibility that such patients may have tampered with their daily take home doses. Larger prospective observational studies are clearly needed to test the supposition of this pilot study.

  2. Fault Diagnosis approach based on a model-based reasoner and a functional designer for a wind turbine. An approach towards self-maintenance

    Science.gov (United States)

    Echavarria, E.; Tomiyama, T.; van Bussel, G. J. W.

    2007-07-01

    The objective of this on-going research is to develop a design methodology to increase the availability for offshore wind farms, by means of an intelligent maintenance system capable of responding to faults by reconfiguring the system or subsystems, without increasing service visits, complexity, or costs. The idea is to make use of the existing functional redundancies within the system and sub-systems to keep the wind turbine operational, even at a reduced capacity if necessary. Re-configuration is intended to be a built-in capability to be used as a repair strategy, based on these existing functionalities provided by the components. The possible solutions can range from using information from adjacent wind turbines, such as wind speed and direction, to setting up different operational modes, for instance re-wiring, re-connecting, changing parameters or control strategy. The methodology described in this paper is based on qualitative physics and consists of a fault diagnosis system based on a model-based reasoner (MBR), and on a functional redundancy designer (FRD). Both design tools make use of a function-behaviour-state (FBS) model. A design methodology based on the re-configuration concept to achieve self-maintained wind turbines is an interesting and promising approach to reduce stoppage rate, failure events, maintenance visits, and to maintain energy output possibly at reduced rate until the next scheduled maintenance.

  3. Fault Diagnosis approach based on a model-based reasoner and a functional designer for a wind turbine. An approach towards self-maintenance

    International Nuclear Information System (INIS)

    Echavarria, E; Tomiyama, T; Bussel, G J W van

    2007-01-01

    The objective of this on-going research is to develop a design methodology to increase the availability for offshore wind farms, by means of an intelligent maintenance system capable of responding to faults by reconfiguring the system or subsystems, without increasing service visits, complexity, or costs. The idea is to make use of the existing functional redundancies within the system and sub-systems to keep the wind turbine operational, even at a reduced capacity if necessary. Re-configuration is intended to be a built-in capability to be used as a repair strategy, based on these existing functionalities provided by the components. The possible solutions can range from using information from adjacent wind turbines, such as wind speed and direction, to setting up different operational modes, for instance re-wiring, re-connecting, changing parameters or control strategy. The methodology described in this paper is based on qualitative physics and consists of a fault diagnosis system based on a model-based reasoner (MBR), and on a functional redundancy designer (FRD). Both design tools make use of a function-behaviour-state (FBS) model. A design methodology based on the re-configuration concept to achieve self-maintained wind turbines is an interesting and promising approach to reduce stoppage rate, failure events, maintenance visits, and to maintain energy output possibly at reduced rate until the next scheduled maintenance

  4. Intelligent control and maintenance of management integrated system based on multi-agents for coal preparation plant

    Energy Technology Data Exchange (ETDEWEB)

    Meng, F.; Wang, Y. [China University of Mining and technology, Xuzhou (China). School of Information and Electrical Engineering

    2006-06-15

    This paper discusses the progress of computer integrated processing (CIPS) of coal preparation and then presents an intelligence controlled production process, device-maintenance and production-management system of coal preparation based on multi-agents (IICMMS-CP). The construction of the IICMMS-CP, the distributed network control system based on live intelligence control stations and the strategy of implementing a distributed intelligence control system are studied in order to overcome the disadvantages brought about by the wide use of the PLC system by coal preparation plants. The software frame, based on a Multi-Agent Intelligence Control and Maintenance Management integrated system, is studied and the implementation methods of IICMMS-CP are discussed. The characteristics of distributed architecture, cooperation and parallel computing meet the needs of integrated control of coal preparation plants with large-scale spatial production distribution, densely-related processes and complex systems. Its application further improves the reliability and precision of process control, accuracy of fault identification and intelligence of production adjustment, establishes a technical basis for system integration and flexible production. The main function of the system has been tested in a coal preparation plant to good effect in stabilizing product quality, improving efficiency and reducing consumption. 17 refs., 4 figs.

  5. Advances in safety related maintenance

    International Nuclear Information System (INIS)

    2000-03-01

    The maintenance of systems, structures and components in nuclear power plants (NPPs) plays an important role in assuring their safe and reliable operation. Worldwide, NPP maintenance managers are seeking to reduce overall maintenance costs while maintaining or improving the levels of safety and reliability. Thus, the issue of NPP maintenance is one of the most challenging aspects of nuclear power generation. There is a direct relation between safety and maintenance. While maintenance alone (apart from modifications) will not make a plant safer than its original design, deficient maintenance may result in either an increased number of transients and challenges to safety systems or reduced reliability and availability of safety systems. The confidence that NPP structures, systems and components will function as designed is ultimately based on programmes which monitor both their reliability and availability to perform their intended safety function. Because of this, approaches to monitor the effectiveness of maintenance are also necessary. An effective maintenance programme ensures that there is a balance between the improvement in component reliability to be achieved and the loss of component function due to maintenance downtime. This implies that the safety level of an NPP should not be adversely affected by maintenance performed during operation. The nuclear industry widely acknowledges the importance of maintenance in NPP safety and operation and therefore devotes great efforts to develop techniques, methods and tools to aid in maintenance planning, follow-up and optimization, and in assuring the effectiveness of maintenance

  6. CALiPER Report 20.4: Lumen and Chromaticity Maintenance of LED PAR38 Lamps Operated in Steady-State Conditions

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-12-30

    This CALiPER report focuses on lumen maintenance, chromaticity maintenance, and catastrophic failure in 32 of the Series 20 LED PAR38 lamps and 8 benchmark lamps, which were monitored for nearly 14,000 hours at ambient temperatures between 44°C and 45°C.

  7. Habit-based interventions for weight loss maintenance in adults with overweight and obesity: a randomized controlled trial.

    Science.gov (United States)

    Cleo, Gina; Glasziou, Paul; Beller, Elaine; Isenring, Elisabeth; Thomas, Rae

    2018-04-23

    The objective of this study was to determine whether habit-based interventions are clinically beneficial in achieving long-term (12-month) weight loss maintenance and explore whether making new habits or breaking old habits is more effective. Volunteer community members aged 18-75 years who had overweight or obesity (BMI ≥ 25 kg/m 2 ) were randomized in a single-blind, three-arm, randomized controlled trial. Ten Top Tips (TTT), Do Something Different (DSD), and the attention-only waitlist (WL) control groups were conducted for 12 weeks from July to October 2015. Participants were followed up post-intervention (all groups) and at 6 and 12-month post-intervention (Ten Top Tips and Do Something Different only). The primary outcome was weight-loss maintenance at 12-month follow-up. Secondary outcomes included weight loss at all time points, fruit and vegetable consumption, exercise, wellbeing, depression, anxiety, habit strength, and openness to change. Of the 130 participants assessed for eligibility, 75 adults (mean BMI 34.5 kg/m 2 [SD 6.2]), with a mean age of 51 years were recruited. Assessments were completed post-intervention by 66/75 (88%) of participants and by 43/50 (86%) at 12 months. At post-intervention, participants in the Ten Top Tips (-3.3 kg; 95% CI -5.2, -1.4) and Do Something Different (-2.9 kg; 95% CI -4.3, -1.4) interventions lost significantly more weight (P = Habit-based weight-loss interventions-forming new habits (TTT) and breaking old habits (DSD), resulted in clinically important weight-loss maintenance at 12-month follow-up.

  8. Maintenance and Outage Management Assessment (MOMA)

    International Nuclear Information System (INIS)

    2005-01-01

    a small team of experienced nuclear experts/specialists in the world. It can be requested for a single area or multiple ones, such as a) In-Service Inspection program review and optimization, including inspection qualification and risk informed inspection, b) maintenance program optimization by means of equipment reliability, performance based approach, risk informed on-line maintenance, condition based maintenance, c) outage improvement be means of streamlined integration of technologies and process, work planning and scheduling, plant modifications and configuration control, indicators and operating experience feedback system, safety culture, outsourcing and contract management, and spare parts

  9. Reliability centred maintenance of nuclear power plant facilities

    International Nuclear Information System (INIS)

    Kovacs, Zoltan; Novakova, Helena; Hlavac, Pavol; Janicek, Frantisek

    2011-01-01

    A method for the optimization of preventive maintenance nuclear power plant equipment, i.e. reliability centred maintenance, is described. The method enables procedures and procedure schedules to be defined such as allow the maintenance cost to be minimized without compromising operational safety or reliability. Also, combinations of facilities which remain available and ensure reliable operation of the reactor unit during the maintenance of other pieces of equipment are identified. The condition-based maintenance concept is used in this process, thereby preventing unnecessary operator interventions into the equipment, which are often associated with human errors. Where probabilistic safety assessment is available, the most important structures, systems and components with the highest maintenance priority can be identified. (orig.)

  10. Some problems of maintenance regulation at Ukrainian nuclear power plants

    International Nuclear Information System (INIS)

    Koltakov, V.

    1997-01-01

    Among all the possible problems arising in a connection with provision of NPP power units safe operation, the maintenance and repair at the Ukrainian NPPs possess an important place. System of maintenance and repair at the Ukrainian NPPs is presently still traditional one, based on the former USSR' document ''Rules of the NPPs Equipment Maintenance and Repair Arrangement'' (RD.53.025.002-088). For to provide technical systems reliability and safety in an accordance with ''General Provisions on NPP Safety'' (OPB-82) (presently OPB-95 is in underway in Ukraine) nuclear operators are implementing their maintenance and repair. These procedures are obligatory conditions for NPP operation during all the life term. To implement an equipment maintenance and repair there are appropriate divisions in NPP structure envisaged such as departments, laboratories, sections, shops, etc. composing an NPP maintenance and repair service. There are also another specific enterprises engaged in such activities. (author). 2 tabs, 4 diagrams

  11. On the Use of Time-Limited Information for Maintenance Decision Support: A Predictive Approach under Maintenance Constraints

    Directory of Open Access Journals (Sweden)

    E. Khoury

    2013-01-01

    Full Text Available This paper deals with a gradually deteriorating system operating under an uncertain environment whose state is only known on a finite rolling horizon. As such, the system is subject to constraints. Maintenance actions can only be planned at imposed times called maintenance opportunities that are available on a limited visibility horizon. This system can, for example, be a commercial vehicle with a monitored critical component that can be maintained only in some specific workshops. Based on the considered system, we aim to use the monitoring data and the time-limited information for maintenance decision support in order to reduce its costs. We propose two predictive maintenance policies based, respectively, on cost and reliability criteria. Classical age-based and condition-based policies are considered as benchmarks. The performance assessment shows the value of the different types of information and the best way to use them in maintenance decision making.

  12. Maintenance Mentor

    National Research Council Canada - National Science Library

    Jacobs, John

    2003-01-01

    Maintenance Mentor (MXM) is a research effort conducted by a joint AFRL/HESR and Northrop Grumman Information Technology team to identify the basic, high-level requirements necessary for improving flight line diagnostic capabilities...

  13. Web-Based Information Management System for the Investigation, Reporting, and Analysis of Human Error in Naval Aviation Maintenance

    National Research Council Canada - National Science Library

    Boex, Anthony

    2001-01-01

    .... The Human Factors Analysis and Classification System-Maintenance Extension (HFACS-ME) taxonomy, a framework for classifying and analyzing the presence of maintenance errors that lead to mishaps, is the foundation of this tool...

  14. Vibration-based condition monitoring industrial, aerospace and automotive applications

    CERN Document Server

    Randall, Robert Bond

    2010-01-01

    ""Without doubt the best modern and up-to-date text on the topic, wirtten by one of the world leading experts in the field. Should be on the desk of any practitioner or researcher involved in the field of Machine Condition Monitoring"" Simon Braun, Israel Institute of Technology Explaining complex ideas in an easy to understand way, Vibration-based Condition Monitoring provides a comprehensive survey of the application of vibration analysis to the condition monitoring of machines. Reflecting the natural progression of these systems by presenting the fundamental material

  15. Pavement maintenance procedures with and without milling materials

    Directory of Open Access Journals (Sweden)

    Rafiqul A. Tarefder

    2016-01-01

    Full Text Available This study evaluates maintenance treatment followed by different Districts of New Mexico Department of Transportation (NMDOT. In addition, two case studies on the use of old pavement materials, called the “millings”, in maintenance projects are reported. Based on this study, it is observed that none of the Districts have a written procedure for maintenance work. Rather Districts rely on the experience of the maintenance crew for conducting maintenance projects. All Districts prefer to use chip seal for maintenance irrespective of distress conditions of the pavements. Patching and crack sealing are usually done before chip sealing to extend the life of the chip seals. Sand seal, scrub seal, and slurry seal projects are not done by District maintenance crews but by outside contractors. It is also observed that all Districts are interested in using millings in maintenance projects and most have already used millings in at least one maintenance project with some success and failure. Most of the Districts have used coarse fraction of millings in chip seal projects successfully. However, they failed to find a proper way to process the fine fractions of millings. Case Study I shows that fine millings can be used to construct thin overlay when mixed with emulsion in pug mill or hot drums. Case Study II concludes that fine millings can be used as fine/sand seal successfully following the same procedure and using the same equipment as chip seal. Keywords: Millings, Maintenance, Emulsion, Rutting, Pug-mill

  16. Generation maintenance scheduling based on multiple ob jectives and their relationship analysis

    Institute of Scientific and Technical Information of China (English)

    Jun-peng ZHAN; Chuang-xin GUO; Qing-hua WU; Lu-liang ZHANG; Hong-jun FU

    2014-01-01

    In a market environment of power systems, each producer pursues its maximal profit while the independent system operator is in charge of the system reliability and the minimization of the total generation cost when generating the generation maintenance scheduling (GMS). Thus, the GMS is inherently a multi-objective optimization problem as its objectives usually conflict with each other. This paper proposes a multi-objective GMS model in a market environment which includes three types of objectives, i.e., each producer’s profit, the system reliability, and the total generation cost. The GMS model has been solved by the group search optimizer with multiple producers (GSOMP) on two test systems. The simulation results show that the model is well solved by the GSOMP with a set of evenly distributed Pareto-optimal solutions obtained. The simulation results also illustrate that one producer’s profit conflicts with another one’s, that the total generation cost does not conflict with the profit of the producer possessing the cheapest units while the total generation cost conflicts with the other producers’ profits, and that the reliability objective conflicts with the other objectives.

  17. Building a new predictor for multiple linear regression technique-based corrective maintenance turnaround time.

    Science.gov (United States)

    Cruz, Antonio M; Barr, Cameron; Puñales-Pozo, Elsa

    2008-01-01

    This research's main goals were to build a predictor for a turnaround time (TAT) indicator for estimating its values and use a numerical clustering technique for finding possible causes of undesirable TAT values. The following stages were used: domain understanding, data characterisation and sample reduction and insight characterisation. Building the TAT indicator multiple linear regression predictor and clustering techniques were used for improving corrective maintenance task efficiency in a clinical engineering department (CED). The indicator being studied was turnaround time (TAT). Multiple linear regression was used for building a predictive TAT value model. The variables contributing to such model were clinical engineering department response time (CE(rt), 0.415 positive coefficient), stock service response time (Stock(rt), 0.734 positive coefficient), priority level (0.21 positive coefficient) and service time (0.06 positive coefficient). The regression process showed heavy reliance on Stock(rt), CE(rt) and priority, in that order. Clustering techniques revealed the main causes of high TAT values. This examination has provided a means for analysing current technical service quality and effectiveness. In doing so, it has demonstrated a process for identifying areas and methods of improvement and a model against which to analyse these methods' effectiveness.

  18. An operator training simulator based on interactive virtual teleoperation: nuclear facilities maintenance applications

    International Nuclear Information System (INIS)

    Kim, Ki Ho; Kim, Seung Ho

    1997-01-01

    Remote manipulation in nuclear hazardous environment is very often complex and difficult to operate and requires excessively careful preparation. Remote slave manipulators for unstructured work are manually controlled by a human operator. Small errors made by the operator via the master manipulator during operation can cause the slave to be surffered from excessive forces and result in considerable damages to the slave iteself and its environment. In this paper, we present a prototype of an operator training simulator for use in nuclear facilities maintenance applications, as part of the ongoing Nuclear Robotics Development Program at Korea Atomic Energy Research Institute (KAERI). The operator training simulator provides a means by which, in virtual task simulation, the operator can try out and train for expected remote tasks that the real slave manipulator will perform in advance. The operator interacts with both the virtual slave and task environment through the real master. Virtual interaction force feedback is provided to the operator. We also describe a man-in-the loop control scheme to realize bilateral force reflection in virtual teleoperation

  19. Condition-based Human Reliability Assessment for digitalized control room

    International Nuclear Information System (INIS)

    Kang, H. G.; Jang, S. C.; Eom, H. S.; Ha, J. J.

    2005-04-01

    In safety-critical systems, the generation failure of an actuation signal is caused by the concurrent failures of the automated systems and an operator action. These two sources of safety signals are complicatedly correlated. The failures of sensors or automated systems will cause a lack of necessary information for a human operator and result in error-forcing contexts such as the loss of corresponding alarms and indications. In the conventional analysis, the Human Error Probabilities (HEP) are estimated based on the assumption of 'normal condition of indications and alarms'. In order to construct a more realistic signal-generation failure model, we have to consider more complicated conditions in a more realistic manner. In this study, we performed two kinds of investigation for addressing this issue. We performed the analytic calculations for estimating the effect of sensors failures on the system unavailability and plant risk. For the single-parameter safety signals, the analysis result reveals that the quantification of the HEP should be performed by focusing on the 'no alarm from the automatic system and corresponding indications unavailable' situation. This study also proposes a Condition-Based Human Reliability Assessment (CBHRA) method in order to address these complicated conditions in a practical way. We apply the CBHRA method to the manual actuation of the safety features such as a reactor trip and auxiliary feedwater actuation in Korean Standard Nuclear Power Plants. In the case of conventional single HEP method, it is very hard to consider the multiple HE conditions. The merit of CBHRA is clearly shown in the application to the AFAS generation where no dominating HE condition exits. In this case, even if the HE conditions are carefully investigated, the single HEP method cannot accommodate the multiple conditions in a fault tree. On the other hand, the application result of the reactor trip in SLOCA shows that if there is a dominating condition, the use

  20. Maintenance optimization after RCM

    International Nuclear Information System (INIS)

    Doyle, E.K.; Lee, C.-G.; Cho, D.

    2005-01-01

    Variant forms of RCM (Reliability Centered Maintenance) have been the maintenance optimizing tools of choice in industry for the last 20 years. Several such optimization techniques have been implemented at the Bruce Nuclear Station. Further cost refinement of the Station preventive maintenance strategy whereby decisions are based on statistical analysis of historical failure data are now being evaluated. The evaluation includes a requirement to demonstrate that earlier optimization projects have long term positive impacts. This proved to be a significant challenge. Eventually a methodology was developed using Crowe/AMSAA (Army Materials Systems Analysis Activity) plots to justify expenditures on further optimization efforts. (authors)

  1. Improving regulatory oversight of maintenance programs

    International Nuclear Information System (INIS)

    Cook, S.

    2008-01-01

    Safe nuclear power plant operation requires that risks due to failure or unavailability of Structures, Systems and Components (SSCs) be minimized. Implementation of an effective maintenance program is a key means for achieving this goal. In its regulatory framework, the important relationship between maintenance and safety is acknowledged by the CNSC. A high level maintenance program requirement is included in the Class I Facilities Regulations. In addition, the operating licence contains a condition based on the principle that the design function and performance of SSCs needs to remain consistent with the plant's design and analysis documents. Nuclear power plant licensees have the primary responsibility for safe operation of their facilities and consequently for implementation of a successful maintenance program. The oversight role of the Canadian Nuclear Safety Commission (CNSC) is to ensure that the licensee carries out that responsibility. The challenge for the CNSC is how to do this consistently and efficiently. Three opportunities for improvement to regulatory maintenance oversight are being pursued. These are related to the regulatory framework, compliance verification inspection activities and monitoring of self-reporting. The regulatory framework has been improved by clarifying expectations through the issuance of S-210 'Maintenance Programs for Nuclear Power Plants'. Inspection activities have been improved by introducing new maintenance inspections into the baseline program. Monitoring is being improved by making better use of self-reported and industry produced maintenance related performance indicators. As with any type of program change, the challenge is to ensure the consistent and optimal application of regulatory activities and resources. This paper is a summary of the CNSC's approach to improving its maintenance oversight strategy. (author)

  2. Employment-Based Abstinence Reinforcement as a Maintenance Intervention for the Treatment of Cocaine Dependence: A Randomized Controlled Trial

    Science.gov (United States)

    DeFulio, Anthony; Donlin, Wendy D.; Wong, Conrad J.; Silverman, Kenneth

    2009-01-01

    Context: Due to the chronic nature of cocaine dependence, long-term maintenance treatments may be required to sustain abstinence. Abstinence reinforcement is among the most effective means of initiating cocaine abstinence. Practical and effective means of maintaining abstinence reinforcement programs over time are needed. Objective: Determine whether employment-based abstinence reinforcement can be an effective long-term maintenance intervention for cocaine dependence. Design: Participants (N=128) were enrolled in a 6-month job skills training and abstinence initiation program. Participants who initiated abstinence, attended regularly, and developed needed job skills during the first six months were hired as operators in a data entry business and randomly assigned to an employment only (Control, n = 24) or abstinence-contingent employment (n = 27) group. Setting: A nonprofit data entry business. Participants: Unemployed welfare recipients who persistently used cocaine while enrolled in methadone treatment in Baltimore. Intervention: Abstinence-contingent employment participants received one year of employment-based contingency management, in which access to employment was contingent on provision drug-free urine samples under routine and then random drug testing. If a participant provided drug-positive urine or failed to provide a mandatory sample, then that participant received a temporary reduction in pay and could not work until urinalysis confirmed recent abstinence. Main Outcome Measure: Cocaine-negative urine samples at monthly assessments across one year of employment. Results: During the one-year of employment, abstinence-contingent employment participants provided significantly more cocaine-negative urine samples than employment only participants (79.3% and 50.7%, respectively; p = 0.004, OR = 3.73, 95% CI = 1.60 – 8.69). Conclusions: Employment-based abstinence reinforcement that includes random drug testing is effective as a long-term maintenance

  3. NaviCell: a web-based environment for navigation, curation and maintenance of large molecular interaction maps.

    Science.gov (United States)

    Kuperstein, Inna; Cohen, David P A; Pook, Stuart; Viara, Eric; Calzone, Laurence; Barillot, Emmanuel; Zinovyev, Andrei

    2013-10-07

    Molecular biology knowledge can be formalized and systematically represented in a computer-readable form as a comprehensive map of molecular interactions. There exist an increasing number of maps of molecular interactions containing detailed and step-wise description of various cell mechanisms. It is difficult to explore these large maps, to organize discussion of their content and to maintain them. Several efforts were recently made to combine these capabilities together in one environment, and NaviCell is one of them. NaviCell is a web-based environment for exploiting large maps of molecular interactions, created in CellDesigner, allowing their easy exploration, curation and maintenance. It is characterized by a combination of three essential features: (1) efficient map browsing based on Google Maps; (2) semantic zooming for viewing different levels of details or of abstraction of the map and (3) integrated web-based blog for collecting community feedback. NaviCell can be easily used by experts in the field of molecular biology for studying molecular entities of interest in the context of signaling pathways and crosstalk between pathways within a global signaling network. NaviCell allows both exploration of detailed molecular mechanisms represented on the map and a more abstract view of the map up to a top-level modular representation. NaviCell greatly facilitates curation, maintenance and updating the comprehensive maps of molecular interactions in an interactive and user-friendly fashion due to an imbedded blogging system. NaviCell provides user-friendly exploration of large-scale maps of molecular interactions, thanks to Google Maps and WordPress interfaces, with which many users are already familiar. Semantic zooming which is used for navigating geographical maps is adopted for molecular maps in NaviCell, making any level of visualization readable. In addition, NaviCell provides a framework for community-based curation of maps.

  4. Designing a future Conditions Database based on LHC experience

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00064378; Formica, Andrea; Gallas, Elizabeth; Lehmann Miotto, Giovanna; Pfeiffer, A.; Govi, G.

    2015-01-01

    We describe a proposal for a new Conditions Database infrastructure that ATLAS and CMS (or other) experiments could use starting on the timescale of Run 3. This proposal is based on the experience that both experiments accumulated during Run 1. We will present the identified relevant data flows for conditions data and underline the common use cases that lead to a joint effort for the development of a new system. Conditions data are needed in any scientific experiment. It includes any ancillary data associated with primary data taking such as detector configuration, state or calibration or the environment in which the detector is operating. In any non-trivial experiment, conditions data typically reside outside the primary data store for various reasons (size, complexity or availability) and are best accessed at the point of processing or analysis (including for Monte Carlo simulations). The ability of any experiment to produce correct and timely results depends on the complete and efficient availability of ne...

  5. Comparative Effectiveness of Tacrolimus-Based Steroid Sparing versus Steroid Maintenance Regimens in Kidney Transplantation: Results from Discrete Event Simulation.

    Science.gov (United States)

    Desai, Vibha C A; Ferrand, Yann; Cavanaugh, Teresa M; Kelton, Christina M L; Caro, J Jaime; Goebel, Jens; Heaton, Pamela C

    2017-10-01

    Corticosteroids used as immunosuppressants to prevent acute rejection (AR) and graft loss (GL) following kidney transplantation are associated with serious cardiovascular and other adverse events. Evidence from short-term randomized controlled trials suggests that many patients on a tacrolimus-based immunosuppressant regimen can withdraw from steroids without increased AR or GL risk. To measure the long-term tradeoff between GL and adverse events for a heterogeneous-risk population and determine the optimal timing of steroid withdrawal. A discrete event simulation was developed including, as events, AR, GL, myocardial infarction (MI), stroke, cytomegalovirus, and new onset diabetes mellitus (NODM), among others. Data from the United States Renal Data System were used to estimate event-specific parametric regressions, which accounted for steroid-sparing regimen (avoidance, early 7-d withdrawal, 6-mo withdrawal, 12-mo withdrawal, and maintenance) as well as patients' demographics, immunologic risks, and comorbidities. Regression-equation results were used to derive individual time-to-event Weibull distributions, used, in turn, to simulate the course of patients over 20 y. Patients on steroid avoidance or an early-withdrawal regimen were more likely to experience AR (45.9% to 55.0% v. 33.6%, P events and other outcomes with no worsening of AR or GL rates compared with steroid maintenance.

  6. End user interface and knowledge base editing system of CSPAR: a knowledge-based consultation system for preventive maintenance in nuclear plants

    International Nuclear Information System (INIS)

    Sinohara, Yasusi; Terano, Takao; Nishiyama, Takuya

    1988-01-01

    Consultation System for Prevention of Abnormal-event Recurrence (CSPAR) is a knowledge-based system to analyze the same kind of events to a given fault reported on a nuclear power plant and to give users some informations for effective measures preventing them. This report discusses the interfaces of CSPAR for both end-users and knowledge-base editors. The interfaces are highly interactive and multi-window oriented. The features are as follows: (1) The end-user interfaces has Japanese language processing facility, which enables the users to consult CSPAR with various synonims and related terms for knowledge-base handling; (2) The knowledge-base editing system is used by knowledge-base editors for maintaining the knowledge on both plants' equipments and abnormal events sequences. It has facilities for easy maintenance of knowledge-bases, which includes a graphic oriented browser, a knowledge-base retriever, and a knowledge-base checker. (author)

  7. Fuzzy Based Decision Support System for Condition Assessment and Rating of Bridges

    Science.gov (United States)

    Srinivas, Voggu; Sasmal, Saptarshi; Karusala, Ramanjaneyulu

    2016-09-01

    In this work, a knowledge based decision support system has been developed to efficiently handle the issues such as distress diagnosis, assessment of damages and condition rating of existing bridges towards developing an exclusive and robust Bridge Management System (BMS) for sustainable bridges. The Knowledge Based Expert System (KBES) diagnoses the distresses and finds the cause of distress in the bridge by processing the data which are heuristic and combined with site inspection results, laboratory test results etc. The coupling of symbolic and numeric type of data has been successfully implemented in the expert system to strengthen its decision making process. Finally, the condition rating of the bridge is carried out using the assessment results obtained from the KBES and the information received from the bridge inspector. A systematic procedure has been developed using fuzzy mathematics for condition rating of bridges by combining the fuzzy weighted average and resolution identity technique. The proposed methodologies and the decision support system will facilitate in developing a robust and exclusive BMS for a network of bridges across the country and allow the bridge engineers and decision makers to carry out maintenance of bridges in a rational and systematic way.

  8. Maintenance Process Strategic Analysis

    Science.gov (United States)

    Jasiulewicz-Kaczmarek, M.; Stachowiak, A.

    2016-08-01

    The performance and competitiveness of manufacturing companies is dependent on the availability, reliability and productivity of their production facilities. Low productivity, downtime, and poor machine performance is often linked to inadequate plant maintenance, which in turn can lead to reduced production levels, increasing costs, lost market opportunities, and lower profits. These pressures have given firms worldwide the motivation to explore and embrace proactive maintenance strategies over the traditional reactive firefighting methods. The traditional view of maintenance has shifted into one of an overall view that encompasses Overall Equipment Efficiency, Stakeholders Management and Life Cycle assessment. From practical point of view it requires changes in approach to maintenance represented by managers and changes in actions performed within maintenance area. Managers have to understand that maintenance is not only about repairs and conservations of machines and devices, but also actions striving for more efficient resources management and care for safety and health of employees. The purpose of the work is to present strategic analysis based on SWOT analysis to identify the opportunities and strengths of maintenance process, to benefit from them as much as possible, as well as to identify weaknesses and threats, so that they could be eliminated or minimized.

  9. Use of probabilistic risk assessment in maintenance activities at Palo Verde

    International Nuclear Information System (INIS)

    Lindquist, R.C.; Pobst, D.S.

    1993-01-01

    Probabilistic risk assessment (PRA) is an important tool in addressing various maintenance activities. At the Palo Verde nuclear generating station (PVNGS), the PRA has been used in a variety of ways to support a wide and diverse selection of maintenance-related activities. For on-line or at-power maintenance, the PRA was used to evaluate combinations of maintenance activities possible with the 12-week or floating maintenance schedule. The maintenance schedule was evaluated to identify any higher risk, undesirable combinations of equipment outages, such as the sole steam-driven auxiliary feedwater pump and the same train emergency diesel generator. Table I is a sampling of the results from the maintenance schedule evaluation in terms of increase in conditional core damage frequency (CDF) above the base- line value due to maintenance on some important key safety systems and combinations thereof. The baseline CDF is 7.4 x 10 -7 per 72 h

  10. Interval of Routine Maintenance and Maintenance Performance: A Literature Review

    Directory of Open Access Journals (Sweden)

    Au-Yong Cheong Peng

    2016-01-01

    Full Text Available In high-rise residential buildings, the quality of facilities management services is significant to the normal operation of the facilities. Unfortunately, lack of concern towards building maintenance, especially preventive maintenance, happens in domestic housing industry in Malaysia. Majority of the maintenance operations of condominiums suffer from lack of planning, lack of proactive maintenance plan, and lack of proper implementation. Thus, this paper reviews the implementation of preventive maintenance strategy, routine maintenance in specific. An extensive review of literature published in 1987 to 2014 is performed for the purpose of this research. The publications are sourced from journal articles, conference proceedings and books. The literature analysis confirms that the routine maintenance of facilities and building services is vital and it can be influential towards the maintenance performance. Subsequently, a theoretical framework is developed, which shows the relationship between routine maintenance of building facilities & services and maintenance performance. The building facilities & services are divided into two categories. They are essential facilities & services that ensure the safety, health, habitability, and operability of buildings; while value-added facilities & services deal with property value, return on investment, and quality living of buildings. Based on the findings, a future research is proposed, which aims to identify the appropriate routine of maintenance for the facilities and services in high-rise residential buildings to improve the maintenance performance.

  11. Effects of citrate-enriched bicarbonate based dialysate on anticoagulation and dialyzer reuse in maintenance hemodialysis patients.

    Science.gov (United States)

    Rocha, Amanda D; Padua, Vanessa C; Oliveira, Esther; Guimaraes, Márcia M; Lugon, Jocemir R; Strogoff de Matos, Jorge P

    2014-04-01

    Systemic anticoagulation with unfractionated heparin is commonly used in maintenance hemodialysis (HD), but it increases the risk of bleeding complications. We investigated whether the use of citrate-enriched bicarbonate based dialysate (CD) would reduce systemic anticoagulation without compromising the efficacy of reprocessed dialyzers. This is a crossover study in which half of a total of 30 patients initially underwent HD with acetate-enriched bicarbonate based dialysate and a standard heparin dose of ∼ 100 IU/kg (Treatment A), whereas the remaining patients were treated with CD and a 30% reduced heparin dose (Treatment B). After 12 consecutive HD sessions in each treatment, the dialysate and heparin doses were reversed, then followed for another period of 12 HD sessions. The two treatment phases were split by a washout period of six HD sessions using acetate-enriched bicarbonate based dialysate and standard heparin dose. Systemic anticoagulation was higher in Treatment A. The activated partial thromboplastin time at the end of HD session was 68 ± 36 seconds in Treatment A and 47 ± 16 seconds in Treatment B (P = 0.005). Sixty-eight percent of the dialyzers remained adequate until the 12th use in Treatment A and 61% did so in Treatment B (P = 0.63). Patients had three and 24 cramps episodes during Treatment A and B, respectively (P < 0.001). Nine and 26 symptomatic intradialytic hypotension episodes were seen in Treatment A and B, respectively, (P = 0.003). In conclusion, the use of CD had a favorable effect on anticoagulation in the extracorporeal circuit in patients on maintenance HD, but it was also associated with more hypotension and cramps. © 2013 International Society for Hemodialysis.

  12. Maintenance of nuclear medicine instruments

    Energy Technology Data Exchange (ETDEWEB)

    Ambro, P

    1993-12-31

    Maintenance of instruments is generally of two kinds: (a) corrective maintenance, on a non-scheduled basis, to restore equipment to a functional status by repairs; (b) preventive maintenance, to keep equipment in a specified functional condition by providing systematic inspection, quality control, detection and correction of early malfunctions. Most of the instruments used in nuclear medicine are rather complex systems built from mechanical, electrical and electronic parts. Any one of these components is liable to fail at some time or other. Repair could be done only by a specialist who is able to evaluate the condition of the various parts ranging from cables to connectors, from scintillators to photomultipliers, from microprocessors to microswitches. The knowledge of the intricacies of the various electronic components required for their repairs is quite wide and varied. The electronics industry turns out more and more multi-purpose chips which can carry out the functions of many parts used in the instruments of the earlier generation. This provides protection against unauthorized copying of the circuits but it serves another purpose as well of inhibiting repairs by non-factory personnel. These trends of the instrument design should be taken into consideration when a policy has to be developed for the repairs of the hospital based equipment 1 fig., 1 tab

  13. Maintenance of nuclear medicine instruments

    International Nuclear Information System (INIS)

    Ambro, P.

    1992-01-01

    Maintenance of instruments is generally of two kinds: (a) corrective maintenance, on a non-scheduled basis, to restore equipment to a functional status by repairs; (b) preventive maintenance, to keep equipment in a specified functional condition by providing systematic inspection, quality control, detection and correction of early malfunctions. Most of the instruments used in nuclear medicine are rather complex systems built from mechanical, electrical and electronic parts. Any one of these components is liable to fail at some time or other. Repair could be done only by a specialist who is able to evaluate the condition of the various parts ranging from cables to connectors, from scintillators to photomultipliers, from microprocessors to microswitches. The knowledge of the intricacies of the various electronic components required for their repairs is quite wide and varied. The electronics industry turns out more and more multi-purpose chips which can carry out the functions of many parts used in the instruments of the earlier generation. This provides protection against unauthorized copying of the circuits but it serves another purpose as well of inhibiting repairs by non-factory personnel. These trends of the instrument design should be taken into consideration when a policy has to be developed for the repairs of the hospital based equipment

  14. Managed maintenance, the next step in power plant maintenance

    International Nuclear Information System (INIS)

    Butterworth, G.; Anderson, T.M.

    1984-01-01

    The Westinghouse Nuclear Services Integration Division managed maintenance services are described. Essential to the management and control of a total plant maintenance programme is the development of a comprehensive maintenance specification. During recent years Westinghouse has jointly developed total plant engineering-based maintenance specifications with a number of utilities. The process employed and the experience to date are described. To efficiently implement the maintenance programme Westinghouse has developed a computer software program specifically designed for day to day use at the power plant by maintenance personnel. This program retains an equipment maintenance history, schedules maintenance activities, issues work orders and performs a number of sophisticated analyses of the maintenance backlog and forecast, equipment failure rates, etc. The functions of this software program are described and details of Westinghouse efforts to support the utilities in reducing outage times through development of predefined outage plans for critical report maintenance activities are given. Also described is the experience gained in the training of specialized maintenance personnel, employing competency-based training techniques and equipment mock-ups, and the benefits experienced, in terms of improved quality and productivity of maintenance performed. The success experienced with these methods has caused Westinghouse to expand the use of these training techniques to the more routine skill areas of power plant maintenance. A significant reduction in the operating costs of nuclear power plants will only be brought about by a significant improvement in the quality of maintenance. Westinghouse intends to effect this change by expanding its international service capabilities and to make major investments in order to promote technological developments in the area of power plant maintenance. (author)

  15. A Methodology for Modeling Nuclear Power Plant Passive Component Aging in Probabilistic Risk Assessment under the Impact of Operating Conditions, Surveillance and Maintenance Activities

    Science.gov (United States)

    Guler Yigitoglu, Askin

    In the context of long operation of nuclear power plants (NPPs) (i.e., 60-80 years, and beyond), investigation of the aging of passive systems, structures and components (SSCs) is important to assess safety margins and to decide on reactor life extension as indicated within the U.S. Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program. In the traditional probabilistic risk assessment (PRA) methodology, evaluating the potential significance of aging of passive SSCs on plant risk is challenging. Although passive SSC failure rates can be added as initiating event frequencies or basic event failure rates in the traditional event-tree/fault-tree methodology, these failure rates are generally based on generic plant failure data which means that the true state of a specific plant is not reflected in a realistic manner on aging effects. Dynamic PRA methodologies have gained attention recently due to their capability to account for the plant state and thus address the difficulties in the traditional PRA modeling of aging effects of passive components using physics-based models (and also in the modeling of digital instrumentation and control systems). Physics-based models can capture the impact of complex aging processes (e.g., fatigue, stress corrosion cracking, flow-accelerated corrosion, etc.) on SSCs and can be utilized to estimate passive SSC failure rates using realistic NPP data from reactor simulation, as well as considering effects of surveillance and maintenance activities. The objectives of this dissertation are twofold: The development of a methodology for the incorporation of aging modeling of passive SSC into a reactor simulation environment to provide a framework for evaluation of their risk contribution in both the dynamic and traditional PRA; and the demonstration of the methodology through its application to pressurizer surge line pipe weld and steam generator tubes in commercial nuclear power plants. In the proposed methodology, a

  16. A probabilistic maintenance model for diesel engines

    Science.gov (United States)

    Pathirana, Shan; Abeygunawardane, Saranga Kumudu

    2018-02-01

    In this paper, a probabilistic maintenance model is developed for inspection based preventive maintenance of diesel engines based on the practical model concepts discussed in the literature. Developed model is solved using real data obtained from inspection and maintenance histories of diesel engines and experts' views. Reliability indices and costs were calculated for the present maintenance policy of diesel engines. A sensitivity analysis is conducted to observe the effect of inspection based preventive maintenance on the life cycle cost of diesel engines.

  17. Operational experience of air washer based ventilation system for power conditioning system of Indus-2

    International Nuclear Information System (INIS)

    Pandey, R.M.; Baghel, S.L.; Parate, J.K.; Ahlawat, Sandeep; Rawlani, B.K.; Chouksey, Sanjay

    2015-01-01

    Indus-2 Synchrotron Accelerator requires high quality conditioned uninterrupted AC mains power for their smooth and reliable operation. Three units of 1670 kVA and one unit of 1100 kVA capacity rotary uninterruptible power conditioning systems (UPS) were installed and commissioned. These UPS units require dust free and cool ambient conditions for smooth operation. In order to meet the ventilation requirements, an evaporative cooling system of 80000 cubic meter/hour capacity with filtration units was designed, installed and commissioned in February 2011 and is operational on round-the-clock basis. Evaporative cooling scheme was chosen as has various advantages over a refrigerated system like lower initial capital costs, lower energy usage, lower running costs, less greenhouse gas and it does not contribute to ozone depletion. The ventilation system filters the environment air in stages up to 5 micron level and being conditioned with an automatic controlled soft water circulating system with cooling pads. An instrumentation and control scheme is included in the system to provide the automation requirements for operating 24 x 7 through the year. All the mechanical, hydraulic and electrical devices are maintained by providing preventive maintenance work without affecting the accelerator machine operation. Availability and reliability of the system was analysed based on the failure data. In Year 2014, the ventilation system was upgraded to accommodate standby blower unit, coupling unit and improved quality of supply air with new air conditioning devices. The control panel monitors the condition of air in the UPS hall and maintainsup to 28°C air temperature and 85% maximum relative humidity in round-the clock shift with more than 98% operational reliability. In this paper, we present design philosophy, installation, instrumentation, testing, operation experience and availability of the ventilation system for Power Conditioning System, Indus complex. (author)

  18. Chinese National Condition Based Power Dispatching Optimization in Microgrids

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2018-01-01

    Full Text Available This paper proposed a study on the power dispatching optimization in the microgrid aiming at Chinese national condition based on PSO algorithm. The whole work is on the basis of the weighted factor variation of the objective function due to different weather conditions. Three cases including the good contamination-diffusing weather condition, the smog weather condition, and the normal condition are considered, respectively. In the case of smog weather, the new energy generation and the battery system will be all out to use as less power as possible from the primary grid so that the pollution produced by coal consumption in the thermal power plants can be upmost reduced. However, in the case of perfect contamination-diffusing weather, the battery is not used to reserve its lifetime, while a large amount of exchanged power from the primary grid is used to obtain a most economic-efficient effect. In normal condition, the power dispatching is performed in a most balanced way considering not only the cost but also the environmental management. The case study in Suzhou Industrial Part confirms the effectiveness of the proposed method in this paper.

  19. Predication of Crane Condition Parameters Based on SVM and AR

    International Nuclear Information System (INIS)

    Xu Xiuzhong; Hu Xiong; Zhou Congxiao

    2011-01-01

    Through statistic analysis of vibration signals of motor on the container crane hoisting mechanism in a port, the feature vectors with vibration are obtained. Through data preprocessing and training data, Training models of condition parameters based on support vector machine (SVM) are established. The testing data of condition monitoring parameters can be predicted by the training models. During training the models, the penalty parameter and kernel function of model are optimized by cross validation. In order to analysis the accurate of SVM model, autoregressive model is used to predict the trend of vibration. The research showed the predicted results of model using SVM are better than the results by autoregressive (AR) modeling.

  20. Comparing Weight Loss-Maintenance Outcomes of a Worksite-Based Lifestyle Program Delivered via DVD and Face-to-Face: A Randomized Trial.

    Science.gov (United States)

    Ing, Claire Townsend; Miyamoto, Robin E S; Fang, Rui; Antonio, Mapuana; Paloma, Diane; Braun, Kathryn L; Kaholokula, Joseph Keawe'aimoku

    2018-03-01

    Native Hawaiians and other Pacific Islanders have high rates of overweight and obesity compared with other ethnic groups in Hawai'i. Effective weight loss and weight loss-maintenance programs are needed to address obesity and obesity-related health inequities for this group. Compare the effectiveness of a 9-month, worksite-based, weight loss-maintenance intervention delivered via DVD versus face-to-face in continued weight reduction and weight loss maintenance beyond the initial weight loss phase. We tested DVD versus face-to-face delivery of the PILI@Work Program's 9-month, weight loss-maintenance phase in Native Hawaiian-serving organizations. After completing the 3-month weight loss phase, participants ( n = 217) were randomized to receive the weight loss-maintenance phase delivered via trained peer facilitators or DVDs. Participant assessments at randomization and postintervention included weight, height, blood pressure, physical functioning, exercise frequency, and fat intake. Eighty-three face-to-face participants were retained at 12 months (74.1%) compared with 73 DVD participants (69.5%). There was no significant difference between groups in weight loss or weight loss maintenance. The number of lessons attended in Phase 1 of the intervention (β = 0.358, p = .022) and baseline systolic blood pressure (β = -0.038, p = .048) predicted percent weight loss at 12 months. Weight loss maintenance was similar across groups. This suggests that low-cost delivery methods for worksite-based interventions targeting at-risk populations can help address obesity and obesity-related disparities. Additionally, attendance during the weight loss phase and lower baseline systolic blood pressure predicted greater percent weight loss during the weight loss-maintenance phase, suggesting that early engagement and initial physical functioning improve long-term weight loss outcomes.