11,932 research outputs found

    Perspectives on trading cost and availability for corrective maintenance at the equipment type level

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    Characterising maintenance costs has always been challenging due to a lack of accurate prior cost data and the uncertainties around equipment usage and reliability. Since preventive maintenance does not completely prevent corrective repairs in demanding environments, any unscheduled maintenance can have a large impact on the overall maintenance costs. This introduces the requirement to set up support contracts with minimum baseline solutions that warrant the target demand within certain costs and risks. This article investigates a process that has been developed to estimate performance based support contract costs attributed to corrective maintenance. These can play a dominant role in the through-life support of high values assets. The case context for the paper is the UK Ministry of Defence. The developed approach allows benchmarking support contract solutions, and enabling efficient planning decisions. Emphasis is placed on learning from feedback, testing and validating current methodologies for estimating corrective maintenance costs and availability at the Equipment Type level. These are interacting sub-equipment's that have unique availability requirements and hence have a much larger impact on the capital maintenance expenditure. The presented case studies demonstrate the applicability of the approach towards adequate savings and improved availability estimates

    Choosing policy instruments for pollution control : a review

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    This paper presents the design of cost effective interventions to protect the environment from excessive pollution in developing countries. The concept of intervention is motivated by the typical explanation for environmental problems in economic theory--external effects. The aim of the paper is to review the relevant theoretical and empirical economic literature in order: (a) to distill the principal lessons and evaluate general rules of thumb; and (b) to identify gaps that need to be filled in order to make them more accessible and relevant to developing countries. The paper defines broadly the range of policy instruments that can be used to address pollution problems in developing countries. It includes instruments that have traditionally been in the realm of public finance, such as taxes, prices and subsidies. But it also covers regulations and other instruments designed to affect the amount of pollution or to mitigate its damage. To limit the scope of this paper, the authors treat pollution control policies, but not policies to address other environmental problems, such as soil erosion, deforestation, desertification or other natural resource problems. Many of the principles presented, however, broadly relate to the problem of correcting for external effects, and can be applied to these other problems as well. It also focuses on domestic problems and does not deal explicitly with trans-national or global pollution externalities.Economic Theory&Research,Water and Industry,Health Monitoring&Evaluation,Pollution Management&Control,Environmental Economics&Policies

    Evaluación del sistema de mantenimiento de la máquina de inyección de plástico mediante el método TOPSIS

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    The following document talks about the parameters of the maintenance system implemented in plastic injection machines of a maquiladora company located in Ciudad Juarez Chihuahua. The method used in this investigation is essentially ulti-criteria decision making, the technique for the order of preference for similarity to the ideal TOPSIS solution. Therefore, an evaluation of the maintenance system is carried out, using measurable collected in said company. With this evaluation the plastic injection machine is determined in better conditions, as well as the machine in worse conditions, which helps management to make better decisions regarding each machine. The objective of this research is to address the study of decision-making in the industrial field specifically in the maintenance system of plastic injection molding machines.El siguiente documento habla sobre los parámetros del sistema de mantenimiento implementado en las máquinas de inyección de plástico de una empresa maquiladora ubicada en Ciudad Juárez Chihuahua. El método utilizado en esta investigación es esencialmente la toma de decisiones multicriterio,  la  técnica  para  el  orden  de  preferencia  por  la  similitud  con  la  solución  ideal  de  TOPSIS.  Por  lo  tanto,  se  realiza  una  evaluación  del  sistema  de  mantenimiento,  utilizando datos medibles recogidos en dicha empresa. Con esta evaluación se determina la máquina de inyección de plástico en mejores condiciones, así como la máquina en peores condiciones, lo que ayuda a la dirección a tomar mejores decisiones respecto a cada máquina. El objetivo de esta investigación es abordar el estudio de la toma de decisiones en el campo industrial específicamente en  el  sistema  de  mantenimiento  de  las  máquinas  de  moldeo  por  inyección  de  plástic

    Developing an academic programme of machinery maintenance for ship crew and shore personnel in Mozambique

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    DECISION SUPPORT MODEL IN FAILURE-BASED COMPUTERIZED MAINTENANCE MANAGEMENT SYSTEM FOR SMALL AND MEDIUM INDUSTRIES

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    Maintenance decision support system is crucial to ensure maintainability and reliability of equipments in production lines. This thesis investigates a few decision support models to aid maintenance management activities in small and medium industries. In order to improve the reliability of resources in production lines, this study introduces a conceptual framework to be used in failure-based maintenance. Maintenance strategies are identified using the Decision-Making Grid model, based on two important factors, including the machines’ downtimes and their frequency of failures. The machines are categorized into three downtime criterions and frequency of failures, which are high, medium and low. This research derived a formula based on maintenance cost, to re-position the machines prior to Decision-Making Grid analysis. Subsequently, the formula on clustering analysis in the Decision-Making Grid model is improved to solve multiple-criteria problem. This research work also introduced a formula to estimate contractor’s response and repair time. The estimates are used as input parameters in the Analytical Hierarchy Process model. The decisions were synthesized using models based on the contractors’ technical skills such as experience in maintenance, skill to diagnose machines and ability to take prompt action during troubleshooting activities. Another important criteria considered in the Analytical Hierarchy Process is the business principles of the contractors, which includes the maintenance quality, tools, equipments and enthusiasm in problem-solving. The raw data collected through observation, interviews and surveys in the case studies to understand some risk factors in small and medium food processing industries. The risk factors are analysed with the Ishikawa Fishbone diagram to reveal delay time in machinery maintenance. The experimental studies are conducted using maintenance records in food processing industries. The Decision Making Grid model can detect the top ten worst production machines on the production lines. The Analytical Hierarchy Process model is used to rank the contractors and their best maintenance practice. This research recommends displaying the results on the production’s indicator boards and implements the strategies on the production shop floor. The proposed models can be used by decision makers to identify maintenance strategies and enhance competitiveness among contractors in failure-based maintenance. The models can be programmed as decision support sub-procedures in computerized maintenance management systems

    Development of hazard analysis and critical control points (HACCP) procedures to control organic chemical hazards in the agricultural production of raw food commodities

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    Hazard Analysis by Critical Control Points (HACCP) is a systematic approach to the identification, assessment and control of hazards in the food chain. Effective HACCP requires the consideration of all possible hazards, i.e., chemical, microbiological and physical. However, current procedures focus primarily upon microbiological and physical hazards, and, to date, chemical aspects of HACCP have received relatively little attention. Consequently, this report discusses the application of HACCP to organic chemical contaminants and the particular problems that are likely to encounter within the agricultural sector. It also presents generic templates for the development of organic chemical contaminant HACCP procedures for selected raw food commodities, i.e., cereal crops, raw meats and milk

    Environmental taxes and policies for developing countries

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    Increasing urbanization and industrialization can exacerbate pollution problems in developing countries. Tax revenues in developing countries are too low to support adequate infrastructure for treating and disposing of wastes, but the problem is also attributable to the classic problem of externalities in productiion and consumption."Externalities"means that the costs of environmental degradation are not considered by the private decisionmakers undertaking the activities that cause the problems. Two types of policies are commonly considered to correct this market failure and improve the allocation of resources: command-and-control policies (such as emmission and abatement standards) and market-based incentive policies (such as emissions charges, taxes on production and consumption, and marketable pollution quotas), which raise the price of such activities for the perpetrators. Market based incentives theoretically reduce pollution at least cost and increase government revenues, but may require costly monitoring to be effective, and are usually implemented in an environment of imperfect information about the costs of abatement. Sometimes command and control policies make more economic sense in this environment. Efficiency gains from curbing pollution in developing countries may be large. Some polluting activities are subsidized, so curtailing them brings both fiscal and environmental benefits. Taxing polluting inputs and outputs is a particularly attractive policy in developing countries which often lack experience in administering and enforcing other types of environmental regulation. Corrective taxes make use of existing administrative structures and increase tax revenues, which can be spent on public goods to improve environmental quality (including treatment facilities for water and sewage, waste disposal, and sanitation) or can be used to reduce other taxes (which are often highly distortionary in countries with a narrow tax base). Which goods and inputs to single out for corrective taxation depends on the main sources of pollution, which varies from country to country. Air pollution from vehicles is growing in many countries where increased fuel taxes, perhaps coupled with improved regulations for vehicle maintenance, may be desirable. Higher taxes on high sulphur coal would curb both industiral and household emissions of sulphur dioxide. Charges can be implemented for fixed site easy to monitor industrial emissions. Subsidies to industries that cause pollution should be phased out and those industries should be subjected to higher than average tax rates.Water and Industry,Economic Theory&Research,Urban Services to the Poor,Urban Services to the Poor,Environmental Economics&Policies

    Current and forthcoming issues in the South African electricity sector

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    One of the contentious issues in electricity reform is whether there are significant gains from restructuring systems that are moderately well run. South Africa's electricity system is a case in point. The sector's state-owned utility, Eskom, has been generating some of the lowest-priced electricity in the world, has largely achieved revenue adequacy, and has financed the bulk of the government's ambitious electrification program. Moreover, the key technical performance indicators of Eskom's generation plants have reached world-class levels. Yet the sector is confronted today with serious challenges. South Africa's electricity system is currently facing a tight demand/supply balance, and the distribution segment of the industry is in serious financial trouble. This paper provides a careful diagnostic assessment of the industry and identifies a range of policy and restructuring options to improve its performance. It suggests removing distribution from municipal control and privatizing it, calls for vertical and horizontal unbundling, and argues that the cost-benefit analysis of different structural options should focus on investment incentives and not just current operating efficiency.Energy Production and Transportation,Electric Power,Environment and Energy Efficiency,Energy and Environment,Infrastructure Economics

    TOWARD AGRICULTURAL ENVIRONMENTAL MANAGEMENT: APPLYING LESSONS FROM CORPORATE ENVIRONMENTAL MANAGEMENT

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    Many business firms both in the U.S. and abroad are practicing corporate environmental management. They are committed to improving the efficiency of material use, energy use and water use; to recycle; to make safer products and processes and to reduce their overall impact on the environment. In pursuing corporate environmental management, some businesses have found that the presumed tradeoff between profits and environmental quality does not always apply. Instead, by innovating and redesigning their products, processes, corporate culture, and organizational strategy, these firms have been able to improve environmental performance and add to profits. These improved profits are sometimes referred to as "innovation offsets" because they result from technological changes to reduce pollution which also reduce production costs (and/or improve productivity) and thereby "offset" the costs of compliance. The necessary technological innovation is pursued when firms take a dynamic investment perspective rather than presume a static tradeoff between profits and environmental quality.Environmental Economics and Policy,
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