• 제목/요약/키워드: life testing

검색결과 1,297건 처리시간 0.029초

Applications of fiber optic sensors for structural health monitoring

  • Kesavan, K.;Ravisankar, K.;Parivallal, S.;Sreeshylam, P.
    • Smart Structures and Systems
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    • 제1권4호
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    • pp.355-368
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    • 2005
  • Large and complex structures are being built now-a-days and, they are required to be functional even under extreme loading and environmental conditions. In order to meet the safety and maintenance demands, there is a need to build sensors integrated structural system, which can sense and provide necessary information about the structural response to complex loading and environment. Sophisticated tools have been developed for the design and construction of civil engineering structures. However, very little has been accomplished in the area of monitoring and rehabilitation. The employment of appropriate sensor is therefore crucial, and efforts must be directed towards non-destructive testing techniques that remain functional throughout the life of the structure. Fiber optic sensors are emerging as a superior non-destructive tool for evaluating the health of civil engineering structures. Flexibility, small in size and corrosion resistance of optical fibers allow them to be directly embedded in concrete structures. The inherent advantages of fiber optic sensors over conventional sensors include high resolution, ability to work in difficult environment, immunity from electromagnetic interference, large band width of signal, low noise and high sensitivity. This paper brings out the potential and current status of technology of fiber optic sensors for civil engineering applications. The importance of employing fiber optic sensors for health monitoring of civil engineering structures has been highlighted. Details of laboratory studies carried out on fiber optic strain sensors to assess their suitability for civil engineering applications are also covered.

Water-Side Oxide Layer Thickness Measurement of the Irradiated PWR Fuel Rod by NDT Method

  • Park, Kwang-June;Park, Yoon-Kyu;Kim, Eun-Ka
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1995년도 추계학술발표회논문집(2)
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    • pp.680-686
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    • 1995
  • It has been known that water-side corrosion of fuel rods in nuclear reactor is accompanied with the loss of metallic wall thickness and pickup of hydrogen. This corrosion is one of the important limiting factors ill the operating life of fuel rods. In connection with the fuel cladding corrosion, a device to measure the water-side oxide layer thickness by means of the eddy-current method without destructing the fuel rod was developed by KAERI. The device was installed on the multi-function testing bench in the nondestructive test hot-cell and its calibration was carried out successfully for the standard rod attached with plastic thin films whose thicknesses are predetermined. It shows good precision within about 10% error. And a PWR fuel rod, one of the J-44 assembly discharged from Kori nuclear power plant Unit-2, has been selected for oxide layer thickness measurements. With the result of data analysis, it appeared that the oxide layer thicknesses of Zircaloy cladding vary with the length of the fuel rod, and their thicknesses were compared with those of the destructive test results to confirm the real thicknesses.

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의치상용 연성 이장재에 대한 mono-poly의 효과 (THE EFFECTS OF MONO-POLY ON THE SOFT DENTURE LINERS)

  • 허지현;진태호;조혜원
    • 대한치과보철학회지
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    • 제38권4호
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    • pp.484-491
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    • 2000
  • Soft denture liners or conditioners may be valuable therapeutic materials. The life of these liners is short and varies, but it can be extended by the use of a mono-poly(polymethyl methacrylate coating material). This study determined whether coating three temporary soft denture liners with mono-poly affected the resiliency of soft liners, and evaluated the ability of mono-poly to prevent water absorption and alcohol loss from the underlying soft liners. $20{\times}12mm$ cylindrical specimens of Coe-Soft, Soft-Liner, Coe-Comfort soft lining materials were made and divided into two groups of mono-poly uncoated(control) and mono-poly coated specimens. Specimens were immersed in water and compressed on an instron universal testing machine and weighed at initial, 24 hours, 1 week, 2 weeks, and 4 weeks. Resiliency was determined by measuring the energy absorbed by the soft liners when stressed to a specific yield point. Mono-poly coating significantly increased the resiliency of the Soft-Liner, but had no effect on the other soft liners. Among the 3 soft liners, Soft-Liner showed the hightest resiliency and modulus of elasticity. The weight loss in Soft-Liner was the least among the 3 liners, and the weight loss in Coe-Soft was decreased by monopoly coating.

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청년층의 경제적 합리성으로 본 희망자녀수와 출산시기 : '저출산트랩'가설을 중심으로 (Testing the Economic Rationality Hypothesis of the Low Fertility Trap Among Korean Youths)

  • 유계숙
    • 가정과삶의질연구
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    • 제31권3호
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    • pp.141-151
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    • 2013
  • The purpose of this study is to test the economic rationality hypothesis of the low fertility trap among 412 college students at 13 private universities located in Seoul. The respondents were requested to complete the self-administered questionnaire, and the hierarchical multiple regression analyses were performed for analyzing the data. The major findings of this study were as follows: First, the students' views on the prospects for their future employability were 54.6% for big business, 64.51% for medium-sized business, and 49.63% for public sector. In the most employable job, the mean desired monthly salary was 3,505,400 won, while the mean expected monthly salary 2,753,600 won. Second, hierarchical regression analyses revealed that the family income in parental home was positively related to youths' consumption aspirations. Finally, the gap between youths' consumption aspirations and their expected income was negatively related to their desired number of children, while not significantly related to their planned age of first child birth. Thus, the low fertility trap hypothesis was supported in terms of birth rate drop, but not supported in terms of childbearing postponement. The implications of the study results are discussed.

결혼이주여성의 임신과 산후 적응 요구 측정도구 개발 (Development of a Scale to Assess Immigrant Women's Needs for Pregnancy and Postpartum Adaptation)

  • 김경원;정금희
    • 여성건강간호학회지
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    • 제19권4호
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    • pp.242-253
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    • 2013
  • Purpose: The purpose of this study was to develop a scale to assess immigrant women's needs for pregnancy and postpartum adaptation and to test the reliability and validity of the scale. Methods: To construct scale items, critical issues and difficulties associated with pregnancy and postpartum adaptation of immigrant women were identified and categorized through a literature review. Fifty-two scale items were constructed, and data for validity and reliability testing was collected with a questionnaire survey from 367 immigrant women. Data were analyzed with descriptive statistics, factor analysis, and reliability coefficients. Results: The final measurement scale to assess immigrant women's pregnancy and postpartum adaptation consisted of 48 items and 7 factors (adaptation to daily activity during pregnancy, cross-cultural understanding and personal respect, understanding of the process of pregnancy and delivery, baby rearing and family support, physical and emotional adaptation after childbirth, nutrition during pregnancy, and sexual life adaptation). The seven factors accounted for 64.26% of the variance, and Cronbach's ${\alpha}$ was .96. Conclusion: The scale developed by this study is a reliable and valid instrument and can be used to assess needs of pregnancy and postpartum adaptation and can be utilized in providing nursing interventions for immigrant women.

가속화 시험을 통한 페놀폼 단열재의 장기성능 비교분석에 관한 연구 (Study on Long-term Performance of Phenolic Foam Insulation through Accelerated Aging Test)

  • 김진희;김상명;김준태
    • 한국태양에너지학회 논문집
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    • 제40권2호
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    • pp.11-23
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    • 2020
  • The application of the high-performance insulation materials for buildings seems to be an essential measure for reducing energy use in buildings. Phenolic foam is a readily available insulation material with thermal conductivity of about 0.018 to 0.020 W/(mK). It has the advantage of higher thermal resistance and better fire resistance compared to other conventional building insulation materials. Insulation material used for building envelope is regarded as one of the decisive factors for building's energy load. Furthermore, the degradation of its thermal performance over time increasingly affects the building's energy use demand. Generally, the life span of conventionally built buildings is expected to be more than 50 years, so the long-term performance of insulation materials is critical. This paper aims to evaluate the long-term performance of phenolic form boards through an accelerated aging test. The tests were conducted according to BS EN 13166 and KS M ISO 11561. Based on the results of the accelerated aging test, the thermal performance variation of the material was analyzed, and then its aged value after 25 years was computed. Also, the characteristics of the phenolic foam board's long-term performance were also examined based on the standard testing methods adopted.

e-Learning 시스템의 성공요인에 대한 탐색적 연구 (Exploring the Success Factors of the e-Learning Systems)

  • 이문봉;김종원
    • 한국정보시스템학회지:정보시스템연구
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    • 제15권4호
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    • pp.171-188
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    • 2006
  • Information technology and the Internet have had a dramatic effect on education method and individual life. Universities and companies we making large investments in e-Learning applications but are hard to pressed to evaluate the success of their e-Learning systems. e-Learning can be seen as not only one of Internet based information systems which can provide education services but also one of teaching-teaming methods which can implement self-directed teaming. This paper tests the updated model of information system success proposed by Delone and McLean using a field study of a e-Learning. The five dimensions - information quality, system quality, service quality, user satisfaction, net benefit - of the updated model are parsimonious framework for organizing the e-learning success metrics identified in the literature. Questionaires are collected from 107 students who are enrolling a e-learning class using online survey. The model is tested using SPSS and LISREL. The results show that information quality and service quality are significant predictors of user satisfaction with the e-Learning system but system quality is not. Also user satisfaction is found to be a strong predictor of the learning performance. This strong association between user satisfaction and teaming performance suggests that user satisfaction may serve as a valid surrogate for teaming performance. Empirical testing of the updated DeLone & McLean model should therefore be extended to cover a wider variety of systems.

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만성질환 자가간호 중범위이론 검증: 성인 중증고혈압환자를 대상으로 (Testing a Middle-Range Theory of Self-Care of Chronic Illness: A Validation for Korean Adult Patients with Severe Hypertension)

  • 길은하;오희영
    • 대한간호학회지
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    • 제48권5호
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    • pp.521-533
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    • 2018
  • Purpose: The aims of this study are to provide a theoretical framework for improving the self-care of adults with severe hypertension and to examine the practical suitability of a middle-range theory of self-care for chronic illness by validating the structural model. Methods: Data were collected at a university hospital in D metropolitan city from July 1 to August 14, 2015. A total of 224 Korean adult patients with severe hypertension were recruited. Data were analyzed using SPSS 22.0 and AMOS 22.0. Results: The results show that the fit index of the hypothetical model meets the recommended level; 7 out of 8 hypothetical model paths were statistically significant. Motivation, self-efficacy, support from others, and accessibility to care showed statistical significance and explained 67.3% of the self-care process. The self-care process explained 45.3%, 63.6%, and 26.5% of quality of life, health, and illness stability, respectively. Conclusion: This model can be used as a theoretical framework for improving self-care among adult Korean patients with severe hypertension. Moreover, the practical suitability and validity of the middle-range theory of self-care for chronic illness is secured.

초등 예비교사들의 해양학적 소양과 해양 관련 주제의 교수 전략에 대한 의견 분석 (An Analysis of Pre-service Elementary Teachers' Oceanographic Literacy and Opinions on Teaching Strategies for Ocean-related Topics)

  • 김동렬
    • 수산해양교육연구
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    • 제29권2호
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    • pp.396-408
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    • 2017
  • This study aims to analyze pre-service elementary teachers' oceanographic literacy, understanding of ocean environmental problems and opinions on teaching strategies for ocean topics. As survey participants, this study selected 126 pre-service elementary teachers. Firstly, as a result of testing their oceanographic literacy, this study found out that out of all the basic principles, 'Oceans Largely Unexplored' was highest in the mean score, followed by 'Human Connections', 'Ocean & Its Life Shape Earth', 'Habitability', 'Biodiversity', 'Weather & Climate' and 'Size of Ocean'. Besides, regarding environmental problems affecting all the aspects of ocean, they mentioned oil spills caused by vessel accidents, so called 'Oil Pollution', as the most serious marine environmental problem. Regarding environmental problems affecting coral reefs, they considered over-fishing as the most serious problem. Secondly, as a result of analyzing their opinions on effective teaching strategies for ocean-related topics in elementary science textbooks, this study found out that regarding topics about understanding the undersea topography in the chapter of the earth and moon, they proposed 'Making an Undersea Topographic Model with Sand' most as an effective teaching strategy. As an effective teaching strategy for the chapter of animals' lives, they proposed 'Classifying Animals with Marine Animal Cards' most. As an effective teaching strategy for the chapter of ground surface changes, they proposed 'Making and Simulating Seashore Topography' most.

A Study on Quality Management and Assessment Model for System-Integration Organization

  • Lee, Byung Yong;Jung, Soo Il
    • 산업경영시스템학회지
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    • 제24권68호
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    • pp.85-94
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    • 2001
  • Most of customers want to know how to develop the computer system they want to get to use according to the their requirements. This study presents a Computer Integration management System for Quality (CISQ) model for system-integration organizations, which need to demonstrate their capability to consistently provide computer integrated system that meets customer satisfaction and applicable regulatory requirements. The Plan.Do.Check.Act(PDCA) cycle called by Doming wheel expresses the basic concept of continuous improvement action in order to emphasize on achieving business goal. It is useful for providing full competence of a system-integration organization to integrate management systems based on the international management system, and to take an advantage in its market. This study specifies International Certification Network Business Excellence Concept(IBEC) approach to ensure a harmonized integration of the variety of management systems and thereby produce synergy effect. The end part of this study specifies a Assessment Model including an assessment concept adding to the compliance audit according to the CISQ for the continuous improvement. A simple application on Failure Modes and Effects Analysis(FMEA) in testing phase in project life cycle has been done.

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