• Title/Summary/Keyword: Periodic maintenance program

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Software Development for the Construction of Periodic Maintenance System (정기보전체계 구축을 위한 소프트웨어개발)

  • 김재중;김원중
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.18 no.35
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    • pp.115-122
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    • 1995
  • This paper is developed with software system for the construction of periodic maintenance. The system includes records of equipment, maintenance work, failure mode analysis and work standards of maintenability, inspection & repair to establish periodic maintenance system. And the software program is designed with user-oriented to analyze maintenance data and maintenance system of periodic interval times. Also machine operator can easily apply maintenance management system in production & manufacturing field. Visual Basic in the environment of Window system is used as computer program language for graphics and data base management in IBM PC.

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Study on tooth mortality after periodontal therapy (치주 치료 후 치아 상실에 관한 연구)

  • Kim, Hyung-Seop;Seok, Jeong-Jin;Kim, Hyun-Chul;Lee, Su-Jeong;Choi, Seoung-Hwan
    • Journal of Periodontal and Implant Science
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    • v.33 no.2
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    • pp.215-223
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    • 2003
  • The main goal of periodontal treatment is the long-term maintenance of teeth. Periodic maintenance program is need to prevent periodontal disease and maintain healthy periodontium. Hirschfeld and Wasserman(1978) studied 600 treated periodontal patients. This study categorized periodontal patients using well-maintained, downhill, extreme downhill groups. The purpose of our study is to evaluate effect of periodontal treatment and analyse tooth loss after periodontal treatment using this classification. The study population of j9 patients had been treated and maintained for mean 5.8 years. All patients were on a periodic maintenance program at 2-, 3-, 4, or 6-month intends. The avenge age of the patients at the time of original therapy was 49.6 years. To analyse tooth loss, modified classification was used on the basis of response to therapy using by Hirschfeld and Wasserman in 1978. The results were as follows : 1. 59 treated patients were lost mean 1.42 teeth per patient for 5.8 years of maintenance period. 2. Maxillary first molars were most frequently lost but mandibular lateral incisors were lost no tooth during maintenance period. 3. Tooth mortality received surgical treatment had similar to received nonsurgical treatment. 4. Tooth loss was more frequent in maxillary teeth than mandibular teeth, and posterior teeth than anterior teeth, and more frequent tendency in male than female.

A Study on Periodic Buffer Allocation for Program Master Schedule (프로그램 공정계획을 위한 주기적 버퍼 설치에 관한 고찰)

  • Koo Kyo-Jin
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • autumn
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    • pp.81-87
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    • 2001
  • In a dynamically changing environment, the manager of a maintenance and remodeling (M/R) program is confronted with an increasing complexity of coordinating and cooperating multi-resource constrained multiple projects. The root causes of the complexity, uncertainty and interdependence, cause an internal disruption of an activity and chain reactions of disturbance propagation that deteriorate the stability and manageability of the program. This paper evaluates previous endeavors to apply production control and management techniques to the construction industry, and investigates the possibility of applying other management concepts and theories to organizational program management. In particular, this paper proposes a buffer allocation model by which periodic buffers are allocated in the flows of program constraint resources to stabilize a program master schedule instead of protecting individual activities. Comparative experiments by Monte Carlo simulations illustrate improved performance of the proposed model in terms of program's goals: productivity, flexibility, and long-term stability.

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Survey on Operation and Maintenance of Hot-wire Anemometers (열선풍속계 보유 및 관리 실태조사와 효율적 관리방안)

  • Ha, Hyun-Chul;Kim, Tae-Hyeung;Kim, Jong-Chul;Shim, Kwang-Jin;Kim, Eun-A;Song, Se-Wook;Oh, Jung-Ryong;Jung, Ho-Keun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.9 no.2
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    • pp.123-134
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    • 1999
  • Hot-wire anemometers are most commonly used in measuring hood capture velocities due to their accuracy and convenience. But it was ques tionable whether they have an appropriate accuracy and they are well maintained. To answer these questions, as eries of survey and the performance test were performed. The average error turns out to be 16.93%. Many of them were out of order due to bad maintenance. They were not frequently calibrated even though the users of anemometers think the periodic calibration is necessary for maintaining the accuracy of anemometers. A possible efficient maintenance program was thus discussed.

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Damage assessment of structures - an US air force office of scientific research structural mechanics perspective

  • Giurgiutiu, Victor
    • Smart Structures and Systems
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    • v.6 no.2
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    • pp.135-146
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    • 2010
  • This paper presents the perspective of the Structural Mechanics program of the Air Force Office of Scientific Research (AFOSR) on the damage assessment of structures for the period 2006-2009 when the author was serving as Program Manager at AFOSR. It is found that damage assessment of structures plays a very important role in assuring the safety and operational readiness of US Air Force fleet. The current fleet has many aging aircraft, which poses a considerable challenge for the operators and maintainers. The nondestructive evaluation technology is rather mature and able to detect damage with considerable reliability during the periodic maintenance inspections. The emerging structural health monitoring methodology has great potential, because it will use on-board damage detection sensors and systems, will be able to offer on-demand structural health bulletins. Considerable fundamental and applied research is still needed to enable the development, implementation, and dissemination of structural health monitoring technology.

Development of a Leading Performance Indicator from Operational Experience and Resilience in a Nuclear Power Plant

  • Nelson, Pamela F.;Martin-Del-Campo, Cecilia;Hallbert, Bruce;Mosleh, Ali
    • Nuclear Engineering and Technology
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    • v.48 no.1
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    • pp.114-128
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    • 2016
  • The development of operational performance indicators is of utmost importance for nuclear power plants, since they measure, track, and trend plant operation. Leading indicators are ideal for reducing the likelihood of consequential events. This paper describes the operational data analysis of the information contained in the Corrective Action Program. The methodology considers human error and organizational factors because of their large contribution to consequential events. The results include a tool developed from the data to be used for the identification, prediction, and reduction of the likelihood of significant consequential events. This tool is based on the resilience curve that was built from the plant's operational data. The stress is described by the number of unresolved condition reports. The strain is represented by the number of preventive maintenance tasks and other periodic work activities (i.e., baseline activities), as well as, closing open corrective actions assigned to different departments to resolve the condition reports (i.e., corrective action workload). Beyond the identified resilience threshold, the stress exceeds the station's ability to operate successfully and there is an increased likelihood that a consequential event will occur. A performance indicator is proposed to reduce the likelihood of consequential events at nuclear power plants.

The effect of supportive periodontal therapy after periodontal treatment : A 1-year follow up. (치주치료 후 유지치주치료의 효과에 관한 평가 : 1년 관찰)

  • Kim, Shin-Young;Kim, Yong-Gun
    • The Journal of the Korean dental association
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    • v.55 no.1
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    • pp.22-29
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    • 2017
  • Purpose : Preservation of the periodontal health of the treated patient requires supportive periodontal therapy for the elimination of periodontal disease. After Phase I therapy is completed, patients are placed on a schedule of periodic recall visits for maintenance care to prevent recurrence of the disease. The amount of tooth loss would be the most relevant criterion in an evaluation of the effect of periodontal treatment, but this would require studies with extremely long follow-up periods. Thus the most commonly used outcome criteria in clinical research have been clinical attachment level change, reduction of pocket depth and bleeding frequency. The purpose of this case study is to identify the effect of supportive periodontal therapy after periodontal flap surgery. Materials & Methods : Following routine hygienic phase of treatment, patients with chronic periodontitis received surgical periodontal treatment. Bleeding on probing, pocket depth and clinical attachment level were measured at baseline, pre-operation and 1 year follow up. All procedures were performed by one operator. Results : One year a total of 28 patients (58sites) to recheck remained, when conducted maintenance program after periodontal flap surgery was observed reduction of bleeding frequency, pocket depth and improvement of clinical attachment level. Conclusion : The results from this study indicate that supportive periodontal therapy after periodontal flap surgery is effective for reduction of bleeding frequency, pocket depth and gain of clinical attachment level.

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A Study on the Diagnosis of Thermal Performance in the Steam Turbine for Generation (발전용 증기터빈 열성능 진단에 관한 연구)

  • Kim, Kwang-Hong;Hong, Eun-Kee;Hwang, Kwang-Won;Jang, Chul-Ho;Kim, Si-Moon
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3236-3240
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    • 2007
  • This paper describes the results of steam turbine performance tests. The objectives of performance test is to exactly evaluate the degradation(decrease in performance) of the coal-fired steam turbine generator in order to provide plant information to help performance engineers identify problems, improve performance, and make economic decisions about scheduling maintenance and optimizing operation. To achieve these goals, the periodic thermal performance tests have been carried out since the initial operation period, 1997. We made the calculation program and guidelines for the tests and developed the performance index of the turbine cycle on the basis of the ASME PTC. By comparing the performance changes throughout the whole operation period, we confirmed the performance reliabilities of the turbine and its conditions.

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Comparative Study on the Technical Standards for the In-Service Inspection of Nuclear Power Plant Components in Several Countries (원전의 가동중검사 관련 각국의 기술기준 비교고찰)

  • Shin, Ho-Sang;Kim, Kyung-Jo;Jang, Chang-Heui;Kang, Suk-Chull
    • Journal of the Korean Society for Nondestructive Testing
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    • v.24 no.2
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    • pp.186-196
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    • 2004
  • In each country, the periodic ISI(In-Service Inspection) is required by the law to protect the public health and property from the potential accident of the nuclear facilities. To support the implementation of ISI program, the prescriptive ISI technical standards have been established. As the key parts of the ISI program, the non-destructive examination techniques are widely used to identify the degree of degradation of the pressure boundary components and welds. Recently, the risk informed-ISI program has been developed and implemented in several countries. Nonetheless, the existing ISI program which prescriptively decides the scope of inspection still has its own significance. In this article, the technical standards of ISI in leading countries like US, france, Canada, and Japan are reviewed and compared with the safety guide by IAEA. An outline to revise the domestic technical standards of ISI has been suggested.

A periodic case study of diesel vehicle drivers exposed to diesel particulate matter in an underground coal mine

  • Lee, Sugil;Jankewicz, Ganyk;Kim, Jung-Hee;Chung, Kwang Bo
    • Environmental Engineering Research
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    • v.23 no.3
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    • pp.265-270
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    • 2018
  • This study was to measure the exposure of diesel vehicle drivers to elemental carbon (EC) as an indicator of diesel particulate matter (DPM) emitted from diesel vehicles in an underground coal mine over 3 years as per NIOSH Method 5040. Our study results (range $10{\mu}g/m^3-377{\mu}g/m^3$ for the loader drivers, $19{\mu}g/m^3-162{\mu}g/m^3$ for the SMV drivers) were similar or less than previous study results (range $5{\mu}g/m^3-2,200{\mu}g/m^3$) for normal mine operations. From this study results, it appeared that the exposures decreased in the second and the third year. It is thought that the reasons for the decreased personal DPM (EC) exposures over the 3 years were related to the following recommendations; more frequent monitoring and maintenance of the diesel vehicles and their DPM filtration systems, more consistent monitoring of the mine's ventilation system and changes of work practices such as minimizing the opening of diesel vehicle windows. An educational program on adverse health effects of exposure to DPM and use of respiratory protection (P2 respirators) also assisted in minimizing driver exposure to DPM.