• Title/Summary/Keyword: Life Extension

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Evaluation of extension in service life and layer thickness reduction of stabilized flexible pavement

  • Nagrale, Prashant P.;Patil, Atulya
    • Advances in Computational Design
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    • v.3 no.2
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    • pp.201-212
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    • 2018
  • Decrease in availability of suitable subbase and base course materials for highway construction leads to a search for economic method of converting locally available troublesome soil to suitable one for highway construction. Present study insights on evaluation of benefits of stabilization of subgrade soils in term of extension in service life (TBR) and layer thickness reduction (LTR). Laboratory investigation consisting of Atterberg limit, Compaction, California Bearing Ratio, unconfined compressive strength and triaxial shear strength tests were carried out on two types of soil for varying percentages of stabilizers. Vertical compressive strains at the top of unstabilized and stabilized subgrade soils were found out by elastoplastic finite element analysis using commercial software ANSYS. The values of vertical compressive strains at the top of unstabilized and stabilized subgrade, were further used to estimate layer thickness reduction or extension in service life of the pavement due to stabilization. Finite element modeling of the flexible pavement layered structure provides modern technology and sophisticated characterization of materials that can be accommodated in the analysis and enhances the reliability for the prediction of pavement response for improved design methodology. If the pavement section is kept same for unstabilized and stabilized subgrade soils, pavement resting on lime, fly ash and fiber stabilized subgrade soil B will have service life 2.84, 1.84 and 1.67 times than that of unstabilized pavement respectively. The flexible pavement resting on stabilized subgrade is beneficial in reducing the construction material. Actual savings would depend on the option exercised by the designer for reducing the thickness of an individual layer.

Visit Care Workers of the Correlation between Job Satisfaction and Quality of Life: Focusing on Gyeonggi Province (방문요양보호사의 직무만족도와 삶의 질의 관계 -경기도 지역 중심으로-)

  • Lee, Hyun-Sim;Nam, Hee-Soo;Kim, Sun-An
    • Journal of Agricultural Extension & Community Development
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    • v.19 no.2
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    • pp.381-408
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    • 2012
  • The subjects of the research were 275 aged care nurses working in Gyeonggi regions. The analysis result showed: job satisfaction in overall situation was 2.87 on a 5 point scale, indicating the level of job satisfaction was lower than average: the quality of life was 2.97, as with job satisfaction, also low. On the other hand, the research outcomes to discern if it affects the lower level of the quality of life, it was found that variables affecting psychological health include job, pay, co-workers, organization, changing an occupation/job; Social environment include job, pay, and promotion (reward), The maintenance of social relations, pay, promotion(reward) and co-workers, changing an occupation/job; variables affecting physical health include job, pay, promotion(reward), changing an occupation/job; The research outcomes confirm that the job satisfaction of aged visit care workers is an important factor affecting their quality of life.

The study of retrofit method for the used control system of Power Plants to improve its reliability (발전소 제어설비의 신뢰성 평가를 이용한 최적 개조방안 도출(보령화력 사례))

  • Shin, Yoon-Oh;Jung, Chang-Ki
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.737-739
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    • 1999
  • All equipment generally has a specified design service life. As an equipment nears the end of its design service life, replacement must be considered. In some cases, it is possible and more economical to continue the usage of the existing equipment for a longer period. So, replacement should be carefully decided considering the feasibility and economic benefits of the existing equipments' life extension. In this paper, assessment procedure for deciding between life extension and replacement of the electronic control system is presented with an application example. In particular estimation of the electronic control system's remaining life is focused on.

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Shelf Life Extension of Korean Fresh Pasta by Modified Atmosphere Packaging

  • Lee, Dong-Sun;Paik, Hyun-Dong;Im, Geun-Hyung;Yeo, Ik-Hyun
    • Preventive Nutrition and Food Science
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    • v.6 no.4
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    • pp.240-243
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    • 2001
  • Fresh pasta was packaged in a modified atmosphere of 22% $CO_2$/78% $N_2$ and compared with a control air package for its quality changes during storage at 8$^{\circ}C$. The modified atmosphere packaging suppressed the microbial growth of total aerobic bacteria and yeasts/molds with a concomitant reduction in the rates of physical and chemical quality changes, and thus successfully extended the shelf life of fresh packs from 20 days of air packs to 40 days based on microbial criterion of 10$^{6}$ cfu/g. The shelf life extension was greater when the initial microbial quality of the product was better.

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Application of High Performance Coatings for Service Life Extension of Steel Bridge Coatings

  • Lee, Chan-Young
    • Corrosion Science and Technology
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    • v.20 no.4
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    • pp.169-174
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    • 2021
  • In this study, performance tests, a field evaluation, and a life cycle cost (LCC) analysis for high performance coating systems were conducted to prepare a plan to reduce the cost of maintenance coating and contribute to the service life extension of steel bridges by applying high performance coatings to steel bridges that will be constructed in the future. From the deterioration models based on the field evaluation for chlorinated rubber and urethane topcoat systems, which have been applied often, the mean service lives were derived as 20.8 and 26.6 years, respectively. For the other coating systems that have not been applied in practice, the coordination factors were differentially applied with evaluation items. The most durable coating system was predicted to be thermal spray coating (TSC) primer/epoxy intermediate coat/fluoride resin topcoat, with a predicted value as long as 42.2 years. The LCC analysis indicates that partial application of high performance coating, such as TSC and fluoride resin, to specific parts vulnerable to corrosion and ultraviolet ray (UV) is more advantageous than the use of general coating systems.

Self-Esteem and Social Support as Predictors of Adjustment to College Students (대학생의 자아존중감과 사회적지지가 대학생활적응에 미치는 영향 - 평택대학교 학생을 중심으로 -)

  • Lim, Kwang-Myeong
    • Journal of Agricultural Extension & Community Development
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    • v.26 no.3
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    • pp.127-141
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    • 2019
  • Self-esteem and social supports are important variable influencing adjustment to college life. This study aims to identify the factors influencing adjustment to college life. Data were collected from 265 usable questionnaires among college students in Pyeongtek University. Results of a factor analysis yielded three dimensions of self-esteem which were talent/attitude and capacity/pride. And results of factor analysis also yielded three dimensions of social supports which were family, friends, and professor supports. Hierarchical regression analysis revealed that capacity/pride and all of social support factors affected significantly for adjustment to college life. And female and aptitude for students' major had a positive affect on adjustment to college life. It was suggested that self-esteem, social supports, and aptitude for students' major should be considered in college management policy.

Self-Efficacy and Social Support as Predictors of Adjustment to College Students (지역 대학생의 자기효능감과 사회적지지가 대학생활 적응에 미치는 영향)

  • Lim, Kwang-Myeong
    • Journal of Agricultural Extension & Community Development
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    • v.28 no.4
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    • pp.175-190
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    • 2021
  • Self-efficacy and social supports are important variable influencing adjustment to college life. This study aims to identify the factors influencing adjustment to college life. Data were collected from 265 usable questionnaires among college students in Pyeongtek University. Results of a factor analysis yielded three dimensions of self-efficacy which were ability to start promotion/ social ability/ ability to carry out activities/ability to overcome hate experiences/ social sustainability. And results of factor analysis also yielded three dimensions of social supports which were family, friends, and professor supports. Hierarchical regression analysis revealed that social ability/ ability to carry out activities/ability to overcome hate experiences and all of social support factors affected significantly for adjustment to college life. And female and attitude for students' major had a positive affect on adjustment to college life. Results suggested that self-efficacy, social supports, and aptitude for students' major should be considered in college management policy.

The effect of TiN and coating parameters on the tool life extension (TiN 및 TiCN 코팅 특성이 공구수명에 미치는 영향에 대한 연구)

  • 백영남;정우창
    • Journal of the Korean institute of surface engineering
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    • v.31 no.6
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    • pp.317-324
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    • 1998
  • TiN and TiCN films were deposited on the high speed steel by Cathode Arc Ion Plating(CAIP) Process to investigate the tool life extension effect. The experiment variables were bias voltage and deposit time for the TiN coating and reactive gas flow rate ($CH_4:N_2$) under fixing deposit pressure, are current, bias voltage for the TiCN coating respectively. The micro structure and mechanical properties were investigated and compared for among the coating conditions using various methods and machining practice.

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